1457c8996SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 21da177e4SLinus Torvalds /* 31da177e4SLinus Torvalds * mm/mmap.c 41da177e4SLinus Torvalds * 51da177e4SLinus Torvalds * Written by obz. 61da177e4SLinus Torvalds * 7046c6884SAlan Cox * Address space accounting code <alan@lxorguk.ukuu.org.uk> 81da177e4SLinus Torvalds */ 91da177e4SLinus Torvalds 10b1de0d13SMitchel Humpherys #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 11b1de0d13SMitchel Humpherys 12e8420a8eSCyril Hrubis #include <linux/kernel.h> 131da177e4SLinus Torvalds #include <linux/slab.h> 144af3c9ccSAlexey Dobriyan #include <linux/backing-dev.h> 151da177e4SLinus Torvalds #include <linux/mm.h> 1617fca131SArnd Bergmann #include <linux/mm_inline.h> 171da177e4SLinus Torvalds #include <linux/shm.h> 181da177e4SLinus Torvalds #include <linux/mman.h> 191da177e4SLinus Torvalds #include <linux/pagemap.h> 201da177e4SLinus Torvalds #include <linux/swap.h> 211da177e4SLinus Torvalds #include <linux/syscalls.h> 22c59ede7bSRandy.Dunlap #include <linux/capability.h> 231da177e4SLinus Torvalds #include <linux/init.h> 241da177e4SLinus Torvalds #include <linux/file.h> 251da177e4SLinus Torvalds #include <linux/fs.h> 261da177e4SLinus Torvalds #include <linux/personality.h> 271da177e4SLinus Torvalds #include <linux/security.h> 281da177e4SLinus Torvalds #include <linux/hugetlb.h> 29c01d5b30SHugh Dickins #include <linux/shmem_fs.h> 301da177e4SLinus Torvalds #include <linux/profile.h> 31b95f1b31SPaul Gortmaker #include <linux/export.h> 321da177e4SLinus Torvalds #include <linux/mount.h> 331da177e4SLinus Torvalds #include <linux/mempolicy.h> 341da177e4SLinus Torvalds #include <linux/rmap.h> 35cddb8a5cSAndrea Arcangeli #include <linux/mmu_notifier.h> 3682f71ae4SKonstantin Khlebnikov #include <linux/mmdebug.h> 37cdd6c482SIngo Molnar #include <linux/perf_event.h> 38120a795dSAl Viro #include <linux/audit.h> 39b15d00b6SAndrea Arcangeli #include <linux/khugepaged.h> 402b144498SSrikar Dronamraju #include <linux/uprobes.h> 411640879aSAndrew Shewmaker #include <linux/notifier.h> 421640879aSAndrew Shewmaker #include <linux/memory.h> 43b1de0d13SMitchel Humpherys #include <linux/printk.h> 4419a809afSAndrea Arcangeli #include <linux/userfaultfd_k.h> 45d977d56cSKonstantin Khlebnikov #include <linux/moduleparam.h> 4662b5f7d0SDave Hansen #include <linux/pkeys.h> 4721292580SAndrea Arcangeli #include <linux/oom.h> 4804f5866eSAndrea Arcangeli #include <linux/sched/mm.h> 491da177e4SLinus Torvalds 507c0f6ba6SLinus Torvalds #include <linux/uaccess.h> 511da177e4SLinus Torvalds #include <asm/cacheflush.h> 521da177e4SLinus Torvalds #include <asm/tlb.h> 53d6dd61c8SJeremy Fitzhardinge #include <asm/mmu_context.h> 541da177e4SLinus Torvalds 55df529cabSJaewon Kim #define CREATE_TRACE_POINTS 56df529cabSJaewon Kim #include <trace/events/mmap.h> 57df529cabSJaewon Kim 5842b77728SJan Beulich #include "internal.h" 5942b77728SJan Beulich 603a459756SKirill Korotaev #ifndef arch_mmap_check 613a459756SKirill Korotaev #define arch_mmap_check(addr, len, flags) (0) 623a459756SKirill Korotaev #endif 633a459756SKirill Korotaev 64d07e2259SDaniel Cashman #ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS 65d07e2259SDaniel Cashman const int mmap_rnd_bits_min = CONFIG_ARCH_MMAP_RND_BITS_MIN; 66d07e2259SDaniel Cashman const int mmap_rnd_bits_max = CONFIG_ARCH_MMAP_RND_BITS_MAX; 67d07e2259SDaniel Cashman int mmap_rnd_bits __read_mostly = CONFIG_ARCH_MMAP_RND_BITS; 68d07e2259SDaniel Cashman #endif 69d07e2259SDaniel Cashman #ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS 70d07e2259SDaniel Cashman const int mmap_rnd_compat_bits_min = CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MIN; 71d07e2259SDaniel Cashman const int mmap_rnd_compat_bits_max = CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MAX; 72d07e2259SDaniel Cashman int mmap_rnd_compat_bits __read_mostly = CONFIG_ARCH_MMAP_RND_COMPAT_BITS; 73d07e2259SDaniel Cashman #endif 74d07e2259SDaniel Cashman 75f4fcd558SKonstantin Khlebnikov static bool ignore_rlimit_data; 76d977d56cSKonstantin Khlebnikov core_param(ignore_rlimit_data, ignore_rlimit_data, bool, 0644); 77d07e2259SDaniel Cashman 78763ecb03SLiam R. Howlett static void unmap_region(struct mm_struct *mm, struct maple_tree *mt, 79e0da382cSHugh Dickins struct vm_area_struct *vma, struct vm_area_struct *prev, 80763ecb03SLiam R. Howlett struct vm_area_struct *next, unsigned long start, 81763ecb03SLiam R. Howlett unsigned long end); 82e0da382cSHugh Dickins 8364e45507SPeter Feiner static pgprot_t vm_pgprot_modify(pgprot_t oldprot, unsigned long vm_flags) 8464e45507SPeter Feiner { 8564e45507SPeter Feiner return pgprot_modify(oldprot, vm_get_page_prot(vm_flags)); 8664e45507SPeter Feiner } 8764e45507SPeter Feiner 8864e45507SPeter Feiner /* Update vma->vm_page_prot to reflect vma->vm_flags. */ 8964e45507SPeter Feiner void vma_set_page_prot(struct vm_area_struct *vma) 9064e45507SPeter Feiner { 9164e45507SPeter Feiner unsigned long vm_flags = vma->vm_flags; 926d2329f8SAndrea Arcangeli pgprot_t vm_page_prot; 9364e45507SPeter Feiner 946d2329f8SAndrea Arcangeli vm_page_prot = vm_pgprot_modify(vma->vm_page_prot, vm_flags); 956d2329f8SAndrea Arcangeli if (vma_wants_writenotify(vma, vm_page_prot)) { 9664e45507SPeter Feiner vm_flags &= ~VM_SHARED; 976d2329f8SAndrea Arcangeli vm_page_prot = vm_pgprot_modify(vm_page_prot, vm_flags); 9864e45507SPeter Feiner } 99c1e8d7c6SMichel Lespinasse /* remove_protection_ptes reads vma->vm_page_prot without mmap_lock */ 1006d2329f8SAndrea Arcangeli WRITE_ONCE(vma->vm_page_prot, vm_page_prot); 10164e45507SPeter Feiner } 10264e45507SPeter Feiner 1031da177e4SLinus Torvalds /* 104c8c06efaSDavidlohr Bueso * Requires inode->i_mapping->i_mmap_rwsem 1051da177e4SLinus Torvalds */ 1061da177e4SLinus Torvalds static void __remove_shared_vm_struct(struct vm_area_struct *vma, 1071da177e4SLinus Torvalds struct file *file, struct address_space *mapping) 1081da177e4SLinus Torvalds { 1091da177e4SLinus Torvalds if (vma->vm_flags & VM_SHARED) 1104bb5f5d9SDavid Herrmann mapping_unmap_writable(mapping); 1111da177e4SLinus Torvalds 1121da177e4SLinus Torvalds flush_dcache_mmap_lock(mapping); 1136b2dbba8SMichel Lespinasse vma_interval_tree_remove(vma, &mapping->i_mmap); 1141da177e4SLinus Torvalds flush_dcache_mmap_unlock(mapping); 1151da177e4SLinus Torvalds } 1161da177e4SLinus Torvalds 1171da177e4SLinus Torvalds /* 1186b2dbba8SMichel Lespinasse * Unlink a file-based vm structure from its interval tree, to hide 119a8fb5618SHugh Dickins * vma from rmap and vmtruncate before freeing its page tables. 1201da177e4SLinus Torvalds */ 121a8fb5618SHugh Dickins void unlink_file_vma(struct vm_area_struct *vma) 1221da177e4SLinus Torvalds { 1231da177e4SLinus Torvalds struct file *file = vma->vm_file; 1241da177e4SLinus Torvalds 1251da177e4SLinus Torvalds if (file) { 1261da177e4SLinus Torvalds struct address_space *mapping = file->f_mapping; 12783cde9e8SDavidlohr Bueso i_mmap_lock_write(mapping); 1281da177e4SLinus Torvalds __remove_shared_vm_struct(vma, file, mapping); 12983cde9e8SDavidlohr Bueso i_mmap_unlock_write(mapping); 1301da177e4SLinus Torvalds } 131a8fb5618SHugh Dickins } 132a8fb5618SHugh Dickins 133a8fb5618SHugh Dickins /* 134763ecb03SLiam R. Howlett * Close a vm structure and free it. 135a8fb5618SHugh Dickins */ 136763ecb03SLiam R. Howlett static void remove_vma(struct vm_area_struct *vma) 137a8fb5618SHugh Dickins { 138a8fb5618SHugh Dickins might_sleep(); 1391da177e4SLinus Torvalds if (vma->vm_ops && vma->vm_ops->close) 1401da177e4SLinus Torvalds vma->vm_ops->close(vma); 141e9714acfSKonstantin Khlebnikov if (vma->vm_file) 142a8fb5618SHugh Dickins fput(vma->vm_file); 143f0be3d32SLee Schermerhorn mpol_put(vma_policy(vma)); 1443928d4f5SLinus Torvalds vm_area_free(vma); 1451da177e4SLinus Torvalds } 1461da177e4SLinus Torvalds 147b62b633eSLiam R. Howlett static inline struct vm_area_struct *vma_prev_limit(struct vma_iterator *vmi, 148b62b633eSLiam R. Howlett unsigned long min) 149b62b633eSLiam R. Howlett { 150b62b633eSLiam R. Howlett return mas_prev(&vmi->mas, min); 151b62b633eSLiam R. Howlett } 152b62b633eSLiam R. Howlett 153b62b633eSLiam R. Howlett static inline int vma_iter_clear_gfp(struct vma_iterator *vmi, 154b62b633eSLiam R. Howlett unsigned long start, unsigned long end, gfp_t gfp) 155b62b633eSLiam R. Howlett { 156b62b633eSLiam R. Howlett vmi->mas.index = start; 157b62b633eSLiam R. Howlett vmi->mas.last = end - 1; 158b62b633eSLiam R. Howlett mas_store_gfp(&vmi->mas, NULL, gfp); 159b62b633eSLiam R. Howlett if (unlikely(mas_is_err(&vmi->mas))) 160b62b633eSLiam R. Howlett return -ENOMEM; 161b62b633eSLiam R. Howlett 162b62b633eSLiam R. Howlett return 0; 163b62b633eSLiam R. Howlett } 164b62b633eSLiam R. Howlett 1652e7ce7d3SLiam R. Howlett /* 1662e7ce7d3SLiam R. Howlett * check_brk_limits() - Use platform specific check of range & verify mlock 1672e7ce7d3SLiam R. Howlett * limits. 1682e7ce7d3SLiam R. Howlett * @addr: The address to check 1692e7ce7d3SLiam R. Howlett * @len: The size of increase. 1702e7ce7d3SLiam R. Howlett * 1712e7ce7d3SLiam R. Howlett * Return: 0 on success. 1722e7ce7d3SLiam R. Howlett */ 1732e7ce7d3SLiam R. Howlett static int check_brk_limits(unsigned long addr, unsigned long len) 1742e7ce7d3SLiam R. Howlett { 1752e7ce7d3SLiam R. Howlett unsigned long mapped_addr; 1762e7ce7d3SLiam R. Howlett 1772e7ce7d3SLiam R. Howlett mapped_addr = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED); 1782e7ce7d3SLiam R. Howlett if (IS_ERR_VALUE(mapped_addr)) 1792e7ce7d3SLiam R. Howlett return mapped_addr; 1802e7ce7d3SLiam R. Howlett 1812e7ce7d3SLiam R. Howlett return mlock_future_check(current->mm, current->mm->def_flags, len); 1822e7ce7d3SLiam R. Howlett } 18392fed820SLiam R. Howlett static int do_brk_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma, 1842e7ce7d3SLiam R. Howlett unsigned long newbrk, unsigned long oldbrk, 185bb177a73SMichal Hocko struct list_head *uf); 18692fed820SLiam R. Howlett static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *brkvma, 187763ecb03SLiam R. Howlett unsigned long addr, unsigned long request, unsigned long flags); 1886a6160a7SHeiko Carstens SYSCALL_DEFINE1(brk, unsigned long, brk) 1891da177e4SLinus Torvalds { 1909bc8039eSYang Shi unsigned long newbrk, oldbrk, origbrk; 1911da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 1922e7ce7d3SLiam R. Howlett struct vm_area_struct *brkvma, *next = NULL; 193a5b4592cSJiri Kosina unsigned long min_brk; 194128557ffSMichel Lespinasse bool populate; 1959bc8039eSYang Shi bool downgraded = false; 196897ab3e0SMike Rapoport LIST_HEAD(uf); 19792fed820SLiam R. Howlett struct vma_iterator vmi; 1981da177e4SLinus Torvalds 199d8ed45c5SMichel Lespinasse if (mmap_write_lock_killable(mm)) 200dc0ef0dfSMichal Hocko return -EINTR; 2011da177e4SLinus Torvalds 2029bc8039eSYang Shi origbrk = mm->brk; 2039bc8039eSYang Shi 204a5b4592cSJiri Kosina #ifdef CONFIG_COMPAT_BRK 2055520e894SJiri Kosina /* 2065520e894SJiri Kosina * CONFIG_COMPAT_BRK can still be overridden by setting 2075520e894SJiri Kosina * randomize_va_space to 2, which will still cause mm->start_brk 2085520e894SJiri Kosina * to be arbitrarily shifted 2095520e894SJiri Kosina */ 2104471a675SJiri Kosina if (current->brk_randomized) 2115520e894SJiri Kosina min_brk = mm->start_brk; 2125520e894SJiri Kosina else 2135520e894SJiri Kosina min_brk = mm->end_data; 214a5b4592cSJiri Kosina #else 215a5b4592cSJiri Kosina min_brk = mm->start_brk; 216a5b4592cSJiri Kosina #endif 217a5b4592cSJiri Kosina if (brk < min_brk) 2181da177e4SLinus Torvalds goto out; 2191e624196SRam Gupta 2201e624196SRam Gupta /* 2211e624196SRam Gupta * Check against rlimit here. If this check is done later after the test 2221e624196SRam Gupta * of oldbrk with newbrk then it can escape the test and let the data 2231e624196SRam Gupta * segment grow beyond its set limit the in case where the limit is 2241e624196SRam Gupta * not page aligned -Ram Gupta 2251e624196SRam Gupta */ 2268764b338SCyrill Gorcunov if (check_data_rlimit(rlimit(RLIMIT_DATA), brk, mm->start_brk, 2278764b338SCyrill Gorcunov mm->end_data, mm->start_data)) 2281e624196SRam Gupta goto out; 2291e624196SRam Gupta 2301da177e4SLinus Torvalds newbrk = PAGE_ALIGN(brk); 2311da177e4SLinus Torvalds oldbrk = PAGE_ALIGN(mm->brk); 2329bc8039eSYang Shi if (oldbrk == newbrk) { 2339bc8039eSYang Shi mm->brk = brk; 2349bc8039eSYang Shi goto success; 2359bc8039eSYang Shi } 2361da177e4SLinus Torvalds 2379bc8039eSYang Shi /* 2389bc8039eSYang Shi * Always allow shrinking brk. 2392e7ce7d3SLiam R. Howlett * do_brk_munmap() may downgrade mmap_lock to read. 2409bc8039eSYang Shi */ 2411da177e4SLinus Torvalds if (brk <= mm->brk) { 2429bc8039eSYang Shi int ret; 2439bc8039eSYang Shi 2442e7ce7d3SLiam R. Howlett /* Search one past newbrk */ 24592fed820SLiam R. Howlett vma_iter_init(&vmi, mm, newbrk); 24692fed820SLiam R. Howlett brkvma = vma_find(&vmi, oldbrk); 247f5ad5083SJason A. Donenfeld if (!brkvma || brkvma->vm_start >= oldbrk) 2482e7ce7d3SLiam R. Howlett goto out; /* mapping intersects with an existing non-brk vma. */ 2499bc8039eSYang Shi /* 2502e7ce7d3SLiam R. Howlett * mm->brk must be protected by write mmap_lock. 2512e7ce7d3SLiam R. Howlett * do_brk_munmap() may downgrade the lock, so update it 2522e7ce7d3SLiam R. Howlett * before calling do_brk_munmap(). 2539bc8039eSYang Shi */ 2549bc8039eSYang Shi mm->brk = brk; 25592fed820SLiam R. Howlett ret = do_brk_munmap(&vmi, brkvma, newbrk, oldbrk, &uf); 2562e7ce7d3SLiam R. Howlett if (ret == 1) { 2572e7ce7d3SLiam R. Howlett downgraded = true; 2582e7ce7d3SLiam R. Howlett goto success; 2592e7ce7d3SLiam R. Howlett } else if (!ret) 2602e7ce7d3SLiam R. Howlett goto success; 2612e7ce7d3SLiam R. Howlett 2629bc8039eSYang Shi mm->brk = origbrk; 2631da177e4SLinus Torvalds goto out; 2641da177e4SLinus Torvalds } 2651da177e4SLinus Torvalds 2662e7ce7d3SLiam R. Howlett if (check_brk_limits(oldbrk, newbrk - oldbrk)) 2672e7ce7d3SLiam R. Howlett goto out; 2682e7ce7d3SLiam R. Howlett 2692e7ce7d3SLiam R. Howlett /* 2702e7ce7d3SLiam R. Howlett * Only check if the next VMA is within the stack_guard_gap of the 2712e7ce7d3SLiam R. Howlett * expansion area 2722e7ce7d3SLiam R. Howlett */ 27392fed820SLiam R. Howlett vma_iter_init(&vmi, mm, oldbrk); 27492fed820SLiam R. Howlett next = vma_find(&vmi, newbrk + PAGE_SIZE + stack_guard_gap); 2751be7107fSHugh Dickins if (next && newbrk + PAGE_SIZE > vm_start_gap(next)) 2761da177e4SLinus Torvalds goto out; 2771da177e4SLinus Torvalds 27892fed820SLiam R. Howlett brkvma = vma_prev_limit(&vmi, mm->start_brk); 2791da177e4SLinus Torvalds /* Ok, looks good - let it rip. */ 28092fed820SLiam R. Howlett if (do_brk_flags(&vmi, brkvma, oldbrk, newbrk - oldbrk, 0) < 0) 2811da177e4SLinus Torvalds goto out; 2822e7ce7d3SLiam R. Howlett 2831da177e4SLinus Torvalds mm->brk = brk; 2849bc8039eSYang Shi 2859bc8039eSYang Shi success: 286128557ffSMichel Lespinasse populate = newbrk > oldbrk && (mm->def_flags & VM_LOCKED) != 0; 2879bc8039eSYang Shi if (downgraded) 288d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 2899bc8039eSYang Shi else 290d8ed45c5SMichel Lespinasse mmap_write_unlock(mm); 291897ab3e0SMike Rapoport userfaultfd_unmap_complete(mm, &uf); 292128557ffSMichel Lespinasse if (populate) 293128557ffSMichel Lespinasse mm_populate(oldbrk, newbrk - oldbrk); 294128557ffSMichel Lespinasse return brk; 295128557ffSMichel Lespinasse 2961da177e4SLinus Torvalds out: 297d8ed45c5SMichel Lespinasse mmap_write_unlock(mm); 298b7204006SAdrian Huang return origbrk; 2991da177e4SLinus Torvalds } 3001da177e4SLinus Torvalds 301d4af56c5SLiam R. Howlett #if defined(CONFIG_DEBUG_VM_MAPLE_TREE) 302d4af56c5SLiam R. Howlett extern void mt_validate(struct maple_tree *mt); 303d4af56c5SLiam R. Howlett extern void mt_dump(const struct maple_tree *mt); 3041da177e4SLinus Torvalds 305d4af56c5SLiam R. Howlett /* Validate the maple tree */ 306d4af56c5SLiam R. Howlett static void validate_mm_mt(struct mm_struct *mm) 307d4af56c5SLiam R. Howlett { 308d4af56c5SLiam R. Howlett struct maple_tree *mt = &mm->mm_mt; 309763ecb03SLiam R. Howlett struct vm_area_struct *vma_mt; 310d4af56c5SLiam R. Howlett 311d4af56c5SLiam R. Howlett MA_STATE(mas, mt, 0, 0); 312d4af56c5SLiam R. Howlett 313d4af56c5SLiam R. Howlett mt_validate(&mm->mm_mt); 314d4af56c5SLiam R. Howlett mas_for_each(&mas, vma_mt, ULONG_MAX) { 315763ecb03SLiam R. Howlett if ((vma_mt->vm_start != mas.index) || 316763ecb03SLiam R. Howlett (vma_mt->vm_end - 1 != mas.last)) { 317d4af56c5SLiam R. Howlett pr_emerg("issue in %s\n", current->comm); 318d4af56c5SLiam R. Howlett dump_stack(); 319d4af56c5SLiam R. Howlett dump_vma(vma_mt); 320d4af56c5SLiam R. Howlett pr_emerg("mt piv: %p %lu - %lu\n", vma_mt, 321d4af56c5SLiam R. Howlett mas.index, mas.last); 322d4af56c5SLiam R. Howlett pr_emerg("mt vma: %p %lu - %lu\n", vma_mt, 323d4af56c5SLiam R. Howlett vma_mt->vm_start, vma_mt->vm_end); 324d4af56c5SLiam R. Howlett 325d4af56c5SLiam R. Howlett mt_dump(mas.tree); 326d4af56c5SLiam R. Howlett if (vma_mt->vm_end != mas.last + 1) { 327d4af56c5SLiam R. Howlett pr_err("vma: %p vma_mt %lu-%lu\tmt %lu-%lu\n", 328d4af56c5SLiam R. Howlett mm, vma_mt->vm_start, vma_mt->vm_end, 329d4af56c5SLiam R. Howlett mas.index, mas.last); 330d4af56c5SLiam R. Howlett mt_dump(mas.tree); 331d4af56c5SLiam R. Howlett } 332d4af56c5SLiam R. Howlett VM_BUG_ON_MM(vma_mt->vm_end != mas.last + 1, mm); 333d4af56c5SLiam R. Howlett if (vma_mt->vm_start != mas.index) { 334d4af56c5SLiam R. Howlett pr_err("vma: %p vma_mt %p %lu - %lu doesn't match\n", 335d4af56c5SLiam R. Howlett mm, vma_mt, vma_mt->vm_start, vma_mt->vm_end); 336d4af56c5SLiam R. Howlett mt_dump(mas.tree); 337d4af56c5SLiam R. Howlett } 338d4af56c5SLiam R. Howlett VM_BUG_ON_MM(vma_mt->vm_start != mas.index, mm); 339d4af56c5SLiam R. Howlett } 340d4af56c5SLiam R. Howlett } 341d4af56c5SLiam R. Howlett } 3421da177e4SLinus Torvalds 343eafd4dc4SRashika Kheria static void validate_mm(struct mm_struct *mm) 3441da177e4SLinus Torvalds { 3451da177e4SLinus Torvalds int bug = 0; 3461da177e4SLinus Torvalds int i = 0; 347763ecb03SLiam R. Howlett struct vm_area_struct *vma; 348763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 349ff26f70fSAndrew Morton 350524e00b3SLiam R. Howlett validate_mm_mt(mm); 351524e00b3SLiam R. Howlett 352763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 353524e00b3SLiam R. Howlett #ifdef CONFIG_DEBUG_VM_RB 35412352d3cSKonstantin Khlebnikov struct anon_vma *anon_vma = vma->anon_vma; 355ed8ea815SMichel Lespinasse struct anon_vma_chain *avc; 356ff26f70fSAndrew Morton 35712352d3cSKonstantin Khlebnikov if (anon_vma) { 35812352d3cSKonstantin Khlebnikov anon_vma_lock_read(anon_vma); 359ed8ea815SMichel Lespinasse list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 360ed8ea815SMichel Lespinasse anon_vma_interval_tree_verify(avc); 36112352d3cSKonstantin Khlebnikov anon_vma_unlock_read(anon_vma); 36212352d3cSKonstantin Khlebnikov } 363524e00b3SLiam R. Howlett #endif 3641da177e4SLinus Torvalds i++; 3651da177e4SLinus Torvalds } 3665a0768f6SMichel Lespinasse if (i != mm->map_count) { 367763ecb03SLiam R. Howlett pr_emerg("map_count %d mas_for_each %d\n", mm->map_count, i); 3685a0768f6SMichel Lespinasse bug = 1; 3695a0768f6SMichel Lespinasse } 37096dad67fSSasha Levin VM_BUG_ON_MM(bug, mm); 3711da177e4SLinus Torvalds } 372524e00b3SLiam R. Howlett 373524e00b3SLiam R. Howlett #else /* !CONFIG_DEBUG_VM_MAPLE_TREE */ 374d4af56c5SLiam R. Howlett #define validate_mm_mt(root) do { } while (0) 3751da177e4SLinus Torvalds #define validate_mm(mm) do { } while (0) 376524e00b3SLiam R. Howlett #endif /* CONFIG_DEBUG_VM_MAPLE_TREE */ 377d3737187SMichel Lespinasse 378bf181b9fSMichel Lespinasse /* 379bf181b9fSMichel Lespinasse * vma has some anon_vma assigned, and is already inserted on that 380bf181b9fSMichel Lespinasse * anon_vma's interval trees. 381bf181b9fSMichel Lespinasse * 382bf181b9fSMichel Lespinasse * Before updating the vma's vm_start / vm_end / vm_pgoff fields, the 383bf181b9fSMichel Lespinasse * vma must be removed from the anon_vma's interval trees using 384bf181b9fSMichel Lespinasse * anon_vma_interval_tree_pre_update_vma(). 385bf181b9fSMichel Lespinasse * 386bf181b9fSMichel Lespinasse * After the update, the vma will be reinserted using 387bf181b9fSMichel Lespinasse * anon_vma_interval_tree_post_update_vma(). 388bf181b9fSMichel Lespinasse * 389c1e8d7c6SMichel Lespinasse * The entire update must be protected by exclusive mmap_lock and by 390bf181b9fSMichel Lespinasse * the root anon_vma's mutex. 391bf181b9fSMichel Lespinasse */ 392bf181b9fSMichel Lespinasse static inline void 393bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(struct vm_area_struct *vma) 394bf181b9fSMichel Lespinasse { 395bf181b9fSMichel Lespinasse struct anon_vma_chain *avc; 396bf181b9fSMichel Lespinasse 397bf181b9fSMichel Lespinasse list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 398bf181b9fSMichel Lespinasse anon_vma_interval_tree_remove(avc, &avc->anon_vma->rb_root); 399bf181b9fSMichel Lespinasse } 400bf181b9fSMichel Lespinasse 401bf181b9fSMichel Lespinasse static inline void 402bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(struct vm_area_struct *vma) 403bf181b9fSMichel Lespinasse { 404bf181b9fSMichel Lespinasse struct anon_vma_chain *avc; 405bf181b9fSMichel Lespinasse 406bf181b9fSMichel Lespinasse list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 407bf181b9fSMichel Lespinasse anon_vma_interval_tree_insert(avc, &avc->anon_vma->rb_root); 408bf181b9fSMichel Lespinasse } 409bf181b9fSMichel Lespinasse 410e8420a8eSCyril Hrubis static unsigned long count_vma_pages_range(struct mm_struct *mm, 411e8420a8eSCyril Hrubis unsigned long addr, unsigned long end) 412e8420a8eSCyril Hrubis { 4132e3af1dbSMatthew Wilcox (Oracle) VMA_ITERATOR(vmi, mm, addr); 414e8420a8eSCyril Hrubis struct vm_area_struct *vma; 4152e3af1dbSMatthew Wilcox (Oracle) unsigned long nr_pages = 0; 416e8420a8eSCyril Hrubis 4172e3af1dbSMatthew Wilcox (Oracle) for_each_vma_range(vmi, vma, end) { 4182e3af1dbSMatthew Wilcox (Oracle) unsigned long vm_start = max(addr, vma->vm_start); 4192e3af1dbSMatthew Wilcox (Oracle) unsigned long vm_end = min(end, vma->vm_end); 420e8420a8eSCyril Hrubis 4212e3af1dbSMatthew Wilcox (Oracle) nr_pages += PHYS_PFN(vm_end - vm_start); 422e8420a8eSCyril Hrubis } 423e8420a8eSCyril Hrubis 424e8420a8eSCyril Hrubis return nr_pages; 425e8420a8eSCyril Hrubis } 426e8420a8eSCyril Hrubis 427c154124fSLiam R. Howlett static void __vma_link_file(struct vm_area_struct *vma, 428c154124fSLiam R. Howlett struct address_space *mapping) 4291da177e4SLinus Torvalds { 4301da177e4SLinus Torvalds if (vma->vm_flags & VM_SHARED) 431cf508b58SMiaohe Lin mapping_allow_writable(mapping); 4321da177e4SLinus Torvalds 4331da177e4SLinus Torvalds flush_dcache_mmap_lock(mapping); 4346b2dbba8SMichel Lespinasse vma_interval_tree_insert(vma, &mapping->i_mmap); 4351da177e4SLinus Torvalds flush_dcache_mmap_unlock(mapping); 4361da177e4SLinus Torvalds } 4371da177e4SLinus Torvalds 438d4af56c5SLiam R. Howlett /* 439d4af56c5SLiam R. Howlett * vma_mas_store() - Store a VMA in the maple tree. 440d4af56c5SLiam R. Howlett * @vma: The vm_area_struct 441d4af56c5SLiam R. Howlett * @mas: The maple state 442d4af56c5SLiam R. Howlett * 443d4af56c5SLiam R. Howlett * Efficient way to store a VMA in the maple tree when the @mas has already 444d4af56c5SLiam R. Howlett * walked to the correct location. 445d4af56c5SLiam R. Howlett * 446d4af56c5SLiam R. Howlett * Note: the end address is inclusive in the maple tree. 447d4af56c5SLiam R. Howlett */ 448d4af56c5SLiam R. Howlett void vma_mas_store(struct vm_area_struct *vma, struct ma_state *mas) 449d4af56c5SLiam R. Howlett { 450d4af56c5SLiam R. Howlett trace_vma_store(mas->tree, vma); 451d4af56c5SLiam R. Howlett mas_set_range(mas, vma->vm_start, vma->vm_end - 1); 452d4af56c5SLiam R. Howlett mas_store_prealloc(mas, vma); 453d4af56c5SLiam R. Howlett } 454d4af56c5SLiam R. Howlett 455d4af56c5SLiam R. Howlett /* 456d4af56c5SLiam R. Howlett * vma_mas_remove() - Remove a VMA from the maple tree. 457d4af56c5SLiam R. Howlett * @vma: The vm_area_struct 458d4af56c5SLiam R. Howlett * @mas: The maple state 459d4af56c5SLiam R. Howlett * 460d4af56c5SLiam R. Howlett * Efficient way to remove a VMA from the maple tree when the @mas has already 461d4af56c5SLiam R. Howlett * been established and points to the correct location. 462d4af56c5SLiam R. Howlett * Note: the end address is inclusive in the maple tree. 463d4af56c5SLiam R. Howlett */ 464d4af56c5SLiam R. Howlett void vma_mas_remove(struct vm_area_struct *vma, struct ma_state *mas) 465d4af56c5SLiam R. Howlett { 466d4af56c5SLiam R. Howlett trace_vma_mas_szero(mas->tree, vma->vm_start, vma->vm_end - 1); 467d4af56c5SLiam R. Howlett mas->index = vma->vm_start; 468d4af56c5SLiam R. Howlett mas->last = vma->vm_end - 1; 469d4af56c5SLiam R. Howlett mas_store_prealloc(mas, NULL); 470d4af56c5SLiam R. Howlett } 471d4af56c5SLiam R. Howlett 472d4af56c5SLiam R. Howlett /* 473d4af56c5SLiam R. Howlett * vma_mas_szero() - Set a given range to zero. Used when modifying a 474d4af56c5SLiam R. Howlett * vm_area_struct start or end. 475d4af56c5SLiam R. Howlett * 4764a423440SIan Cowan * @mas: The maple tree ma_state 477d4af56c5SLiam R. Howlett * @start: The start address to zero 478d4af56c5SLiam R. Howlett * @end: The end address to zero. 479d4af56c5SLiam R. Howlett */ 480d4af56c5SLiam R. Howlett static inline void vma_mas_szero(struct ma_state *mas, unsigned long start, 481d4af56c5SLiam R. Howlett unsigned long end) 482d4af56c5SLiam R. Howlett { 483d4af56c5SLiam R. Howlett trace_vma_mas_szero(mas->tree, start, end - 1); 484d4af56c5SLiam R. Howlett mas_set_range(mas, start, end - 1); 485d4af56c5SLiam R. Howlett mas_store_prealloc(mas, NULL); 486d4af56c5SLiam R. Howlett } 487d4af56c5SLiam R. Howlett 488763ecb03SLiam R. Howlett static int vma_link(struct mm_struct *mm, struct vm_area_struct *vma) 4891da177e4SLinus Torvalds { 49079e4f2caSLiam R. Howlett VMA_ITERATOR(vmi, mm, 0); 4911da177e4SLinus Torvalds struct address_space *mapping = NULL; 4921da177e4SLinus Torvalds 49379e4f2caSLiam R. Howlett if (vma_iter_prealloc(&vmi)) 494d4af56c5SLiam R. Howlett return -ENOMEM; 495d4af56c5SLiam R. Howlett 49664ac4940SHuang Shijie if (vma->vm_file) { 4971da177e4SLinus Torvalds mapping = vma->vm_file->f_mapping; 49883cde9e8SDavidlohr Bueso i_mmap_lock_write(mapping); 49964ac4940SHuang Shijie } 5001da177e4SLinus Torvalds 50179e4f2caSLiam R. Howlett vma_iter_store(&vmi, vma); 5021da177e4SLinus Torvalds 503c154124fSLiam R. Howlett if (mapping) { 504c154124fSLiam R. Howlett __vma_link_file(vma, mapping); 50583cde9e8SDavidlohr Bueso i_mmap_unlock_write(mapping); 506c154124fSLiam R. Howlett } 5071da177e4SLinus Torvalds 5081da177e4SLinus Torvalds mm->map_count++; 5091da177e4SLinus Torvalds validate_mm(mm); 510d4af56c5SLiam R. Howlett return 0; 5111da177e4SLinus Torvalds } 5121da177e4SLinus Torvalds 5131da177e4SLinus Torvalds /* 5144dd1b841SLiam R. Howlett * vma_expand - Expand an existing VMA 5154dd1b841SLiam R. Howlett * 5164dd1b841SLiam R. Howlett * @mas: The maple state 5174dd1b841SLiam R. Howlett * @vma: The vma to expand 5184dd1b841SLiam R. Howlett * @start: The start of the vma 5194dd1b841SLiam R. Howlett * @end: The exclusive end of the vma 5204dd1b841SLiam R. Howlett * @pgoff: The page offset of vma 5214dd1b841SLiam R. Howlett * @next: The current of next vma. 5224dd1b841SLiam R. Howlett * 5234dd1b841SLiam R. Howlett * Expand @vma to @start and @end. Can expand off the start and end. Will 5244dd1b841SLiam R. Howlett * expand over @next if it's different from @vma and @end == @next->vm_end. 5254dd1b841SLiam R. Howlett * Checking if the @vma can expand and merge with @next needs to be handled by 5264dd1b841SLiam R. Howlett * the caller. 5274dd1b841SLiam R. Howlett * 5284dd1b841SLiam R. Howlett * Returns: 0 on success 5294dd1b841SLiam R. Howlett */ 530*3c441ab7SLiam R. Howlett inline int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma, 5314dd1b841SLiam R. Howlett unsigned long start, unsigned long end, pgoff_t pgoff, 5324dd1b841SLiam R. Howlett struct vm_area_struct *next) 5334dd1b841SLiam R. Howlett { 5344dd1b841SLiam R. Howlett struct mm_struct *mm = vma->vm_mm; 5354dd1b841SLiam R. Howlett struct address_space *mapping = NULL; 5364dd1b841SLiam R. Howlett struct rb_root_cached *root = NULL; 5374dd1b841SLiam R. Howlett struct anon_vma *anon_vma = vma->anon_vma; 5384dd1b841SLiam R. Howlett struct file *file = vma->vm_file; 5394dd1b841SLiam R. Howlett bool remove_next = false; 5404dd1b841SLiam R. Howlett 5414dd1b841SLiam R. Howlett if (next && (vma != next) && (end == next->vm_end)) { 5424dd1b841SLiam R. Howlett remove_next = true; 5434dd1b841SLiam R. Howlett if (next->anon_vma && !vma->anon_vma) { 5444dd1b841SLiam R. Howlett int error; 5454dd1b841SLiam R. Howlett 5464dd1b841SLiam R. Howlett anon_vma = next->anon_vma; 5474dd1b841SLiam R. Howlett vma->anon_vma = anon_vma; 5484dd1b841SLiam R. Howlett error = anon_vma_clone(vma, next); 5494dd1b841SLiam R. Howlett if (error) 5504dd1b841SLiam R. Howlett return error; 5514dd1b841SLiam R. Howlett } 5524dd1b841SLiam R. Howlett } 5534dd1b841SLiam R. Howlett 5544dd1b841SLiam R. Howlett /* Not merging but overwriting any part of next is not handled. */ 5554dd1b841SLiam R. Howlett VM_BUG_ON(next && !remove_next && next != vma && end > next->vm_start); 5564dd1b841SLiam R. Howlett /* Only handles expanding */ 5574dd1b841SLiam R. Howlett VM_BUG_ON(vma->vm_start < start || vma->vm_end > end); 5584dd1b841SLiam R. Howlett 559*3c441ab7SLiam R. Howlett if (vma_iter_prealloc(vmi)) 5604dd1b841SLiam R. Howlett goto nomem; 5614dd1b841SLiam R. Howlett 5624dd1b841SLiam R. Howlett vma_adjust_trans_huge(vma, start, end, 0); 5634dd1b841SLiam R. Howlett 5644dd1b841SLiam R. Howlett if (file) { 5654dd1b841SLiam R. Howlett mapping = file->f_mapping; 5664dd1b841SLiam R. Howlett root = &mapping->i_mmap; 5674dd1b841SLiam R. Howlett uprobe_munmap(vma, vma->vm_start, vma->vm_end); 5684dd1b841SLiam R. Howlett i_mmap_lock_write(mapping); 5694dd1b841SLiam R. Howlett } 5704dd1b841SLiam R. Howlett 5714dd1b841SLiam R. Howlett if (anon_vma) { 5724dd1b841SLiam R. Howlett anon_vma_lock_write(anon_vma); 5734dd1b841SLiam R. Howlett anon_vma_interval_tree_pre_update_vma(vma); 5744dd1b841SLiam R. Howlett } 5754dd1b841SLiam R. Howlett 5764dd1b841SLiam R. Howlett if (file) { 5774dd1b841SLiam R. Howlett flush_dcache_mmap_lock(mapping); 5784dd1b841SLiam R. Howlett vma_interval_tree_remove(vma, root); 5794dd1b841SLiam R. Howlett } 5804dd1b841SLiam R. Howlett 5814dd1b841SLiam R. Howlett vma->vm_start = start; 5824dd1b841SLiam R. Howlett vma->vm_end = end; 5834dd1b841SLiam R. Howlett vma->vm_pgoff = pgoff; 584*3c441ab7SLiam R. Howlett vma_iter_store(vmi, vma); 5854dd1b841SLiam R. Howlett 5864dd1b841SLiam R. Howlett if (file) { 5874dd1b841SLiam R. Howlett vma_interval_tree_insert(vma, root); 5884dd1b841SLiam R. Howlett flush_dcache_mmap_unlock(mapping); 5894dd1b841SLiam R. Howlett } 5904dd1b841SLiam R. Howlett 5914dd1b841SLiam R. Howlett /* Expanding over the next vma */ 592763ecb03SLiam R. Howlett if (remove_next && file) { 5934dd1b841SLiam R. Howlett __remove_shared_vm_struct(next, file, mapping); 5944dd1b841SLiam R. Howlett } 5954dd1b841SLiam R. Howlett 5964dd1b841SLiam R. Howlett if (anon_vma) { 5974dd1b841SLiam R. Howlett anon_vma_interval_tree_post_update_vma(vma); 5984dd1b841SLiam R. Howlett anon_vma_unlock_write(anon_vma); 5994dd1b841SLiam R. Howlett } 6004dd1b841SLiam R. Howlett 6014dd1b841SLiam R. Howlett if (file) { 6024dd1b841SLiam R. Howlett i_mmap_unlock_write(mapping); 6034dd1b841SLiam R. Howlett uprobe_mmap(vma); 6044dd1b841SLiam R. Howlett } 6054dd1b841SLiam R. Howlett 6064dd1b841SLiam R. Howlett if (remove_next) { 6074dd1b841SLiam R. Howlett if (file) { 6084dd1b841SLiam R. Howlett uprobe_munmap(next, next->vm_start, next->vm_end); 6094dd1b841SLiam R. Howlett fput(file); 6104dd1b841SLiam R. Howlett } 6114dd1b841SLiam R. Howlett if (next->anon_vma) 6124dd1b841SLiam R. Howlett anon_vma_merge(vma, next); 6134dd1b841SLiam R. Howlett mm->map_count--; 6144dd1b841SLiam R. Howlett mpol_put(vma_policy(next)); 6154dd1b841SLiam R. Howlett vm_area_free(next); 6164dd1b841SLiam R. Howlett } 6174dd1b841SLiam R. Howlett 6184dd1b841SLiam R. Howlett validate_mm(mm); 6194dd1b841SLiam R. Howlett return 0; 6204dd1b841SLiam R. Howlett 6214dd1b841SLiam R. Howlett nomem: 6224dd1b841SLiam R. Howlett return -ENOMEM; 6234dd1b841SLiam R. Howlett } 6244dd1b841SLiam R. Howlett 6254dd1b841SLiam R. Howlett /* 6261da177e4SLinus Torvalds * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that 6271da177e4SLinus Torvalds * is already present in an i_mmap tree without adjusting the tree. 6281da177e4SLinus Torvalds * The following helper function should be used when such adjustments 6291da177e4SLinus Torvalds * are necessary. The "insert" vma (if any) is to be inserted 6301da177e4SLinus Torvalds * before we drop the necessary locks. 6311da177e4SLinus Torvalds */ 632e86f15eeSAndrea Arcangeli int __vma_adjust(struct vm_area_struct *vma, unsigned long start, 633e86f15eeSAndrea Arcangeli unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert, 634e86f15eeSAndrea Arcangeli struct vm_area_struct *expand) 6351da177e4SLinus Torvalds { 6361da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 6371cd916d0SAndrew Morton struct vm_area_struct *next_next = NULL; /* uninit var warning */ 6381cd916d0SAndrew Morton struct vm_area_struct *next = find_vma(mm, vma->vm_end); 639524e00b3SLiam R. Howlett struct vm_area_struct *orig_vma = vma; 6401da177e4SLinus Torvalds struct address_space *mapping = NULL; 641f808c13fSDavidlohr Bueso struct rb_root_cached *root = NULL; 642012f1800SRik van Riel struct anon_vma *anon_vma = NULL; 6431da177e4SLinus Torvalds struct file *file = vma->vm_file; 644524e00b3SLiam R. Howlett bool vma_changed = false; 6451da177e4SLinus Torvalds long adjust_next = 0; 6461da177e4SLinus Torvalds int remove_next = 0; 647d4af56c5SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 648734537c9SKirill A. Shutemov struct vm_area_struct *exporter = NULL, *importer = NULL; 649287d97acSLinus Torvalds 650d4af56c5SLiam R. Howlett if (next && !insert) { 6511da177e4SLinus Torvalds if (end >= next->vm_end) { 6521da177e4SLinus Torvalds /* 6531da177e4SLinus Torvalds * vma expands, overlapping all the next, and 6541da177e4SLinus Torvalds * perhaps the one after too (mprotect case 6). 65586d12e47SAndrea Arcangeli * The only other cases that gets here are 656e86f15eeSAndrea Arcangeli * case 1, case 7 and case 8. 657e86f15eeSAndrea Arcangeli */ 658e86f15eeSAndrea Arcangeli if (next == expand) { 659e86f15eeSAndrea Arcangeli /* 660e86f15eeSAndrea Arcangeli * The only case where we don't expand "vma" 661e86f15eeSAndrea Arcangeli * and we expand "next" instead is case 8. 662e86f15eeSAndrea Arcangeli */ 663e86f15eeSAndrea Arcangeli VM_WARN_ON(end != next->vm_end); 664e86f15eeSAndrea Arcangeli /* 665e86f15eeSAndrea Arcangeli * remove_next == 3 means we're 666e86f15eeSAndrea Arcangeli * removing "vma" and that to do so we 667e86f15eeSAndrea Arcangeli * swapped "vma" and "next". 668e86f15eeSAndrea Arcangeli */ 669e86f15eeSAndrea Arcangeli remove_next = 3; 670e86f15eeSAndrea Arcangeli VM_WARN_ON(file != next->vm_file); 671e86f15eeSAndrea Arcangeli swap(vma, next); 672e86f15eeSAndrea Arcangeli } else { 673e86f15eeSAndrea Arcangeli VM_WARN_ON(expand != vma); 674e86f15eeSAndrea Arcangeli /* 675e86f15eeSAndrea Arcangeli * case 1, 6, 7, remove_next == 2 is case 6, 676e86f15eeSAndrea Arcangeli * remove_next == 1 is case 1 or 7. 6771da177e4SLinus Torvalds */ 678734537c9SKirill A. Shutemov remove_next = 1 + (end > next->vm_end); 679d4af56c5SLiam R. Howlett if (remove_next == 2) 680d4af56c5SLiam R. Howlett next_next = find_vma(mm, next->vm_end); 681d4af56c5SLiam R. Howlett 682e86f15eeSAndrea Arcangeli VM_WARN_ON(remove_next == 2 && 683763ecb03SLiam R. Howlett end != next_next->vm_end); 684e86f15eeSAndrea Arcangeli } 685e86f15eeSAndrea Arcangeli 686287d97acSLinus Torvalds exporter = next; 6871da177e4SLinus Torvalds importer = vma; 688734537c9SKirill A. Shutemov 689734537c9SKirill A. Shutemov /* 690734537c9SKirill A. Shutemov * If next doesn't have anon_vma, import from vma after 691734537c9SKirill A. Shutemov * next, if the vma overlaps with it. 692734537c9SKirill A. Shutemov */ 69397a42cd4SAndrea Arcangeli if (remove_next == 2 && !next->anon_vma) 694763ecb03SLiam R. Howlett exporter = next_next; 695734537c9SKirill A. Shutemov 6961da177e4SLinus Torvalds } else if (end > next->vm_start) { 6971da177e4SLinus Torvalds /* 6981da177e4SLinus Torvalds * vma expands, overlapping part of the next: 6991da177e4SLinus Torvalds * mprotect case 5 shifting the boundary up. 7001da177e4SLinus Torvalds */ 701f9d86a60SWei Yang adjust_next = (end - next->vm_start); 702287d97acSLinus Torvalds exporter = next; 7031da177e4SLinus Torvalds importer = vma; 704e86f15eeSAndrea Arcangeli VM_WARN_ON(expand != importer); 7051da177e4SLinus Torvalds } else if (end < vma->vm_end) { 7061da177e4SLinus Torvalds /* 7071da177e4SLinus Torvalds * vma shrinks, and !insert tells it's not 7081da177e4SLinus Torvalds * split_vma inserting another: so it must be 7091da177e4SLinus Torvalds * mprotect case 4 shifting the boundary down. 7101da177e4SLinus Torvalds */ 711f9d86a60SWei Yang adjust_next = -(vma->vm_end - end); 712287d97acSLinus Torvalds exporter = vma; 7131da177e4SLinus Torvalds importer = next; 714e86f15eeSAndrea Arcangeli VM_WARN_ON(expand != importer); 7151da177e4SLinus Torvalds } 7161da177e4SLinus Torvalds 7175beb4930SRik van Riel /* 7185beb4930SRik van Riel * Easily overlooked: when mprotect shifts the boundary, 7195beb4930SRik van Riel * make sure the expanding vma has anon_vma set if the 7205beb4930SRik van Riel * shrinking vma had, to cover any anon pages imported. 7215beb4930SRik van Riel */ 722287d97acSLinus Torvalds if (exporter && exporter->anon_vma && !importer->anon_vma) { 723c4ea95d7SDaniel Forrest int error; 724c4ea95d7SDaniel Forrest 725287d97acSLinus Torvalds importer->anon_vma = exporter->anon_vma; 726b800c91aSKonstantin Khlebnikov error = anon_vma_clone(importer, exporter); 7273fe89b3eSLeon Yu if (error) 728b800c91aSKonstantin Khlebnikov return error; 729b800c91aSKonstantin Khlebnikov } 7305beb4930SRik van Riel } 73137f9f559SKirill A. Shutemov 732c5d5546eSVernon Yang if (mas_preallocate(&mas, GFP_KERNEL)) 733d4af56c5SLiam R. Howlett return -ENOMEM; 734d4af56c5SLiam R. Howlett 735d4af56c5SLiam R. Howlett vma_adjust_trans_huge(orig_vma, start, end, adjust_next); 7361da177e4SLinus Torvalds if (file) { 7371da177e4SLinus Torvalds mapping = file->f_mapping; 7381da177e4SLinus Torvalds root = &mapping->i_mmap; 739cbc91f71SSrikar Dronamraju uprobe_munmap(vma, vma->vm_start, vma->vm_end); 740682968e0SSrikar Dronamraju 741682968e0SSrikar Dronamraju if (adjust_next) 74227ba0644SKirill A. Shutemov uprobe_munmap(next, next->vm_start, next->vm_end); 743682968e0SSrikar Dronamraju 74483cde9e8SDavidlohr Bueso i_mmap_lock_write(mapping); 745c154124fSLiam R. Howlett if (insert && insert->vm_file) { 7461da177e4SLinus Torvalds /* 7476b2dbba8SMichel Lespinasse * Put into interval tree now, so instantiated pages 7481da177e4SLinus Torvalds * are visible to arm/parisc __flush_dcache_page 7491da177e4SLinus Torvalds * throughout; but we cannot insert into address 7501da177e4SLinus Torvalds * space until vma start or end is updated. 7511da177e4SLinus Torvalds */ 752c154124fSLiam R. Howlett __vma_link_file(insert, insert->vm_file->f_mapping); 7531da177e4SLinus Torvalds } 7541da177e4SLinus Torvalds } 7551da177e4SLinus Torvalds 756012f1800SRik van Riel anon_vma = vma->anon_vma; 757bf181b9fSMichel Lespinasse if (!anon_vma && adjust_next) 758bf181b9fSMichel Lespinasse anon_vma = next->anon_vma; 759bf181b9fSMichel Lespinasse if (anon_vma) { 760e86f15eeSAndrea Arcangeli VM_WARN_ON(adjust_next && next->anon_vma && 761e86f15eeSAndrea Arcangeli anon_vma != next->anon_vma); 7624fc3f1d6SIngo Molnar anon_vma_lock_write(anon_vma); 763bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(vma); 764bf181b9fSMichel Lespinasse if (adjust_next) 765bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(next); 766bf181b9fSMichel Lespinasse } 767012f1800SRik van Riel 7680fc48a6eSWei Yang if (file) { 7691da177e4SLinus Torvalds flush_dcache_mmap_lock(mapping); 7706b2dbba8SMichel Lespinasse vma_interval_tree_remove(vma, root); 7711da177e4SLinus Torvalds if (adjust_next) 7726b2dbba8SMichel Lespinasse vma_interval_tree_remove(next, root); 7731da177e4SLinus Torvalds } 7741da177e4SLinus Torvalds 775d3737187SMichel Lespinasse if (start != vma->vm_start) { 7763b0e81a1SLiam R. Howlett if ((vma->vm_start < start) && 7773b0e81a1SLiam R. Howlett (!insert || (insert->vm_end != start))) { 778524e00b3SLiam R. Howlett vma_mas_szero(&mas, vma->vm_start, start); 7793b0e81a1SLiam R. Howlett VM_WARN_ON(insert && insert->vm_start > vma->vm_start); 7803b0e81a1SLiam R. Howlett } else { 781524e00b3SLiam R. Howlett vma_changed = true; 7823b0e81a1SLiam R. Howlett } 7831da177e4SLinus Torvalds vma->vm_start = start; 784d3737187SMichel Lespinasse } 785d3737187SMichel Lespinasse if (end != vma->vm_end) { 7863b0e81a1SLiam R. Howlett if (vma->vm_end > end) { 7873b0e81a1SLiam R. Howlett if (!insert || (insert->vm_start != end)) { 788524e00b3SLiam R. Howlett vma_mas_szero(&mas, end, vma->vm_end); 789763ecb03SLiam R. Howlett mas_reset(&mas); 7903b0e81a1SLiam R. Howlett VM_WARN_ON(insert && 7913b0e81a1SLiam R. Howlett insert->vm_end < vma->vm_end); 7923b0e81a1SLiam R. Howlett } 7933b0e81a1SLiam R. Howlett } else { 794524e00b3SLiam R. Howlett vma_changed = true; 7953b0e81a1SLiam R. Howlett } 7961da177e4SLinus Torvalds vma->vm_end = end; 797d3737187SMichel Lespinasse } 798d4af56c5SLiam R. Howlett 799524e00b3SLiam R. Howlett if (vma_changed) 800d4af56c5SLiam R. Howlett vma_mas_store(vma, &mas); 801d4af56c5SLiam R. Howlett 8021da177e4SLinus Torvalds vma->vm_pgoff = pgoff; 8031da177e4SLinus Torvalds if (adjust_next) { 804f9d86a60SWei Yang next->vm_start += adjust_next; 805f9d86a60SWei Yang next->vm_pgoff += adjust_next >> PAGE_SHIFT; 806d4af56c5SLiam R. Howlett vma_mas_store(next, &mas); 8071da177e4SLinus Torvalds } 8081da177e4SLinus Torvalds 8090fc48a6eSWei Yang if (file) { 8101da177e4SLinus Torvalds if (adjust_next) 8116b2dbba8SMichel Lespinasse vma_interval_tree_insert(next, root); 8126b2dbba8SMichel Lespinasse vma_interval_tree_insert(vma, root); 8131da177e4SLinus Torvalds flush_dcache_mmap_unlock(mapping); 8141da177e4SLinus Torvalds } 8151da177e4SLinus Torvalds 816763ecb03SLiam R. Howlett if (remove_next && file) { 8171da177e4SLinus Torvalds __remove_shared_vm_struct(next, file, mapping); 818d4af56c5SLiam R. Howlett if (remove_next == 2) 819d4af56c5SLiam R. Howlett __remove_shared_vm_struct(next_next, file, mapping); 8201da177e4SLinus Torvalds } else if (insert) { 8211da177e4SLinus Torvalds /* 8221da177e4SLinus Torvalds * split_vma has split insert from vma, and needs 8231da177e4SLinus Torvalds * us to insert it before dropping the locks 8241da177e4SLinus Torvalds * (it may either follow vma or precede it). 8251da177e4SLinus Torvalds */ 826763ecb03SLiam R. Howlett mas_reset(&mas); 827763ecb03SLiam R. Howlett vma_mas_store(insert, &mas); 828763ecb03SLiam R. Howlett mm->map_count++; 8291da177e4SLinus Torvalds } 8301da177e4SLinus Torvalds 831bf181b9fSMichel Lespinasse if (anon_vma) { 832bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(vma); 833bf181b9fSMichel Lespinasse if (adjust_next) 834bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(next); 83508b52706SKonstantin Khlebnikov anon_vma_unlock_write(anon_vma); 836bf181b9fSMichel Lespinasse } 8371da177e4SLinus Torvalds 8380fc48a6eSWei Yang if (file) { 839808fbdbeSWei Yang i_mmap_unlock_write(mapping); 8407b2d81d4SIngo Molnar uprobe_mmap(vma); 8412b144498SSrikar Dronamraju 8422b144498SSrikar Dronamraju if (adjust_next) 8437b2d81d4SIngo Molnar uprobe_mmap(next); 8442b144498SSrikar Dronamraju } 8452b144498SSrikar Dronamraju 8461da177e4SLinus Torvalds if (remove_next) { 847d4af56c5SLiam R. Howlett again: 848925d1c40SMatt Helsley if (file) { 849cbc91f71SSrikar Dronamraju uprobe_munmap(next, next->vm_start, next->vm_end); 8501da177e4SLinus Torvalds fput(file); 851925d1c40SMatt Helsley } 8525beb4930SRik van Riel if (next->anon_vma) 8535beb4930SRik van Riel anon_vma_merge(vma, next); 8541da177e4SLinus Torvalds mm->map_count--; 8553964acd0SOleg Nesterov mpol_put(vma_policy(next)); 856524e00b3SLiam R. Howlett if (remove_next != 2) 857524e00b3SLiam R. Howlett BUG_ON(vma->vm_end < next->vm_end); 8583928d4f5SLinus Torvalds vm_area_free(next); 859524e00b3SLiam R. Howlett 8601da177e4SLinus Torvalds /* 8611da177e4SLinus Torvalds * In mprotect's case 6 (see comments on vma_merge), 862763ecb03SLiam R. Howlett * we must remove next_next too. 8631da177e4SLinus Torvalds */ 864734537c9SKirill A. Shutemov if (remove_next == 2) { 865734537c9SKirill A. Shutemov remove_next = 1; 866763ecb03SLiam R. Howlett next = next_next; 8671da177e4SLinus Torvalds goto again; 868fb8c41e9SAndrea Arcangeli } 8691da177e4SLinus Torvalds } 8702b144498SSrikar Dronamraju if (insert && file) 8717b2d81d4SIngo Molnar uprobe_mmap(insert); 8721da177e4SLinus Torvalds 8733b0e81a1SLiam R. Howlett mas_destroy(&mas); 8741da177e4SLinus Torvalds validate_mm(mm); 875763ecb03SLiam R. Howlett 8765beb4930SRik van Riel return 0; 8771da177e4SLinus Torvalds } 8781da177e4SLinus Torvalds 8791da177e4SLinus Torvalds /* 8801da177e4SLinus Torvalds * If the vma has a ->close operation then the driver probably needs to release 8811da177e4SLinus Torvalds * per-vma resources, so we don't attempt to merge those. 8821da177e4SLinus Torvalds */ 8831da177e4SLinus Torvalds static inline int is_mergeable_vma(struct vm_area_struct *vma, 88419a809afSAndrea Arcangeli struct file *file, unsigned long vm_flags, 8859a10064fSColin Cross struct vm_userfaultfd_ctx vm_userfaultfd_ctx, 8865c26f6acSSuren Baghdasaryan struct anon_vma_name *anon_name) 8871da177e4SLinus Torvalds { 88834228d47SCyrill Gorcunov /* 88934228d47SCyrill Gorcunov * VM_SOFTDIRTY should not prevent from VMA merging, if we 89034228d47SCyrill Gorcunov * match the flags but dirty bit -- the caller should mark 89134228d47SCyrill Gorcunov * merged VMA as dirty. If dirty bit won't be excluded from 8928bb4e7a2SWei Yang * comparison, we increase pressure on the memory system forcing 89334228d47SCyrill Gorcunov * the kernel to generate new VMAs when old one could be 89434228d47SCyrill Gorcunov * extended instead. 89534228d47SCyrill Gorcunov */ 89634228d47SCyrill Gorcunov if ((vma->vm_flags ^ vm_flags) & ~VM_SOFTDIRTY) 8971da177e4SLinus Torvalds return 0; 8981da177e4SLinus Torvalds if (vma->vm_file != file) 8991da177e4SLinus Torvalds return 0; 9001da177e4SLinus Torvalds if (vma->vm_ops && vma->vm_ops->close) 9011da177e4SLinus Torvalds return 0; 90219a809afSAndrea Arcangeli if (!is_mergeable_vm_userfaultfd_ctx(vma, vm_userfaultfd_ctx)) 90319a809afSAndrea Arcangeli return 0; 9045c26f6acSSuren Baghdasaryan if (!anon_vma_name_eq(anon_vma_name(vma), anon_name)) 9059a10064fSColin Cross return 0; 9061da177e4SLinus Torvalds return 1; 9071da177e4SLinus Torvalds } 9081da177e4SLinus Torvalds 9091da177e4SLinus Torvalds static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1, 910965f55deSShaohua Li struct anon_vma *anon_vma2, 911965f55deSShaohua Li struct vm_area_struct *vma) 9121da177e4SLinus Torvalds { 913965f55deSShaohua Li /* 914965f55deSShaohua Li * The list_is_singular() test is to avoid merging VMA cloned from 915965f55deSShaohua Li * parents. This can improve scalability caused by anon_vma lock. 916965f55deSShaohua Li */ 917965f55deSShaohua Li if ((!anon_vma1 || !anon_vma2) && (!vma || 918965f55deSShaohua Li list_is_singular(&vma->anon_vma_chain))) 919965f55deSShaohua Li return 1; 920965f55deSShaohua Li return anon_vma1 == anon_vma2; 9211da177e4SLinus Torvalds } 9221da177e4SLinus Torvalds 9231da177e4SLinus Torvalds /* 9241da177e4SLinus Torvalds * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) 9251da177e4SLinus Torvalds * in front of (at a lower virtual address and file offset than) the vma. 9261da177e4SLinus Torvalds * 9271da177e4SLinus Torvalds * We cannot merge two vmas if they have differently assigned (non-NULL) 9281da177e4SLinus Torvalds * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. 9291da177e4SLinus Torvalds * 9301da177e4SLinus Torvalds * We don't check here for the merged mmap wrapping around the end of pagecache 93145e55300SPeter Collingbourne * indices (16TB on ia32) because do_mmap() does not permit mmap's which 9321da177e4SLinus Torvalds * wrap, nor mmaps which cover the final page at index -1UL. 9331da177e4SLinus Torvalds */ 9341da177e4SLinus Torvalds static int 9351da177e4SLinus Torvalds can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags, 93619a809afSAndrea Arcangeli struct anon_vma *anon_vma, struct file *file, 93719a809afSAndrea Arcangeli pgoff_t vm_pgoff, 9389a10064fSColin Cross struct vm_userfaultfd_ctx vm_userfaultfd_ctx, 9395c26f6acSSuren Baghdasaryan struct anon_vma_name *anon_name) 9401da177e4SLinus Torvalds { 9419a10064fSColin Cross if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx, anon_name) && 942965f55deSShaohua Li is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { 9431da177e4SLinus Torvalds if (vma->vm_pgoff == vm_pgoff) 9441da177e4SLinus Torvalds return 1; 9451da177e4SLinus Torvalds } 9461da177e4SLinus Torvalds return 0; 9471da177e4SLinus Torvalds } 9481da177e4SLinus Torvalds 9491da177e4SLinus Torvalds /* 9501da177e4SLinus Torvalds * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) 9511da177e4SLinus Torvalds * beyond (at a higher virtual address and file offset than) the vma. 9521da177e4SLinus Torvalds * 9531da177e4SLinus Torvalds * We cannot merge two vmas if they have differently assigned (non-NULL) 9541da177e4SLinus Torvalds * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. 9551da177e4SLinus Torvalds */ 9561da177e4SLinus Torvalds static int 9571da177e4SLinus Torvalds can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, 95819a809afSAndrea Arcangeli struct anon_vma *anon_vma, struct file *file, 95919a809afSAndrea Arcangeli pgoff_t vm_pgoff, 9609a10064fSColin Cross struct vm_userfaultfd_ctx vm_userfaultfd_ctx, 9615c26f6acSSuren Baghdasaryan struct anon_vma_name *anon_name) 9621da177e4SLinus Torvalds { 9639a10064fSColin Cross if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx, anon_name) && 964965f55deSShaohua Li is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { 9651da177e4SLinus Torvalds pgoff_t vm_pglen; 966d6e93217SLibin vm_pglen = vma_pages(vma); 9671da177e4SLinus Torvalds if (vma->vm_pgoff + vm_pglen == vm_pgoff) 9681da177e4SLinus Torvalds return 1; 9691da177e4SLinus Torvalds } 9701da177e4SLinus Torvalds return 0; 9711da177e4SLinus Torvalds } 9721da177e4SLinus Torvalds 9731da177e4SLinus Torvalds /* 9749a10064fSColin Cross * Given a mapping request (addr,end,vm_flags,file,pgoff,anon_name), 9759a10064fSColin Cross * figure out whether that can be merged with its predecessor or its 9769a10064fSColin Cross * successor. Or both (it neatly fills a hole). 9771da177e4SLinus Torvalds * 9781da177e4SLinus Torvalds * In most cases - when called for mmap, brk or mremap - [addr,end) is 9791da177e4SLinus Torvalds * certain not to be mapped by the time vma_merge is called; but when 9801da177e4SLinus Torvalds * called for mprotect, it is certain to be already mapped (either at 9811da177e4SLinus Torvalds * an offset within prev, or at the start of next), and the flags of 9821da177e4SLinus Torvalds * this area are about to be changed to vm_flags - and the no-change 9831da177e4SLinus Torvalds * case has already been eliminated. 9841da177e4SLinus Torvalds * 9851da177e4SLinus Torvalds * The following mprotect cases have to be considered, where AAAA is 9861da177e4SLinus Torvalds * the area passed down from mprotect_fixup, never extending beyond one 9871da177e4SLinus Torvalds * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after: 9881da177e4SLinus Torvalds * 9895d42ab29SWei Yang * AAAA AAAA AAAA 9905d42ab29SWei Yang * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN 9915d42ab29SWei Yang * cannot merge might become might become 9925d42ab29SWei Yang * PPNNNNNNNNNN PPPPPPPPPPNN 9935d42ab29SWei Yang * mmap, brk or case 4 below case 5 below 9945d42ab29SWei Yang * mremap move: 9955d42ab29SWei Yang * AAAA AAAA 9965d42ab29SWei Yang * PPPP NNNN PPPPNNNNXXXX 9975d42ab29SWei Yang * might become might become 9985d42ab29SWei Yang * PPPPPPPPPPPP 1 or PPPPPPPPPPPP 6 or 9995d42ab29SWei Yang * PPPPPPPPNNNN 2 or PPPPPPPPXXXX 7 or 10005d42ab29SWei Yang * PPPPNNNNNNNN 3 PPPPXXXXXXXX 8 10011da177e4SLinus Torvalds * 10028bb4e7a2SWei Yang * It is important for case 8 that the vma NNNN overlapping the 1003e86f15eeSAndrea Arcangeli * region AAAA is never going to extended over XXXX. Instead XXXX must 1004e86f15eeSAndrea Arcangeli * be extended in region AAAA and NNNN must be removed. This way in 1005e86f15eeSAndrea Arcangeli * all cases where vma_merge succeeds, the moment vma_adjust drops the 1006e86f15eeSAndrea Arcangeli * rmap_locks, the properties of the merged vma will be already 1007e86f15eeSAndrea Arcangeli * correct for the whole merged range. Some of those properties like 1008e86f15eeSAndrea Arcangeli * vm_page_prot/vm_flags may be accessed by rmap_walks and they must 1009e86f15eeSAndrea Arcangeli * be correct for the whole merged range immediately after the 1010e86f15eeSAndrea Arcangeli * rmap_locks are released. Otherwise if XXXX would be removed and 1011e86f15eeSAndrea Arcangeli * NNNN would be extended over the XXXX range, remove_migration_ptes 1012e86f15eeSAndrea Arcangeli * or other rmap walkers (if working on addresses beyond the "end" 1013e86f15eeSAndrea Arcangeli * parameter) may establish ptes with the wrong permissions of NNNN 1014e86f15eeSAndrea Arcangeli * instead of the right permissions of XXXX. 10151da177e4SLinus Torvalds */ 10161da177e4SLinus Torvalds struct vm_area_struct *vma_merge(struct mm_struct *mm, 10171da177e4SLinus Torvalds struct vm_area_struct *prev, unsigned long addr, 10181da177e4SLinus Torvalds unsigned long end, unsigned long vm_flags, 10191da177e4SLinus Torvalds struct anon_vma *anon_vma, struct file *file, 102019a809afSAndrea Arcangeli pgoff_t pgoff, struct mempolicy *policy, 10219a10064fSColin Cross struct vm_userfaultfd_ctx vm_userfaultfd_ctx, 10225c26f6acSSuren Baghdasaryan struct anon_vma_name *anon_name) 10231da177e4SLinus Torvalds { 10241da177e4SLinus Torvalds pgoff_t pglen = (end - addr) >> PAGE_SHIFT; 1025eef19944SJakub Matěna struct vm_area_struct *mid, *next, *res; 1026eef19944SJakub Matěna int err = -1; 1027eef19944SJakub Matěna bool merge_prev = false; 1028eef19944SJakub Matěna bool merge_next = false; 10291da177e4SLinus Torvalds 10301da177e4SLinus Torvalds /* 10311da177e4SLinus Torvalds * We later require that vma->vm_flags == vm_flags, 10321da177e4SLinus Torvalds * so this tests vma->vm_flags & VM_SPECIAL, too. 10331da177e4SLinus Torvalds */ 10341da177e4SLinus Torvalds if (vm_flags & VM_SPECIAL) 10351da177e4SLinus Torvalds return NULL; 10361da177e4SLinus Torvalds 1037763ecb03SLiam R. Howlett next = find_vma(mm, prev ? prev->vm_end : 0); 1038eef19944SJakub Matěna mid = next; 1039eef19944SJakub Matěna if (next && next->vm_end == end) /* cases 6, 7, 8 */ 1040763ecb03SLiam R. Howlett next = find_vma(mm, next->vm_end); 10411da177e4SLinus Torvalds 1042e86f15eeSAndrea Arcangeli /* verify some invariant that must be enforced by the caller */ 1043e86f15eeSAndrea Arcangeli VM_WARN_ON(prev && addr <= prev->vm_start); 1044eef19944SJakub Matěna VM_WARN_ON(mid && end > mid->vm_end); 1045e86f15eeSAndrea Arcangeli VM_WARN_ON(addr >= end); 1046e86f15eeSAndrea Arcangeli 1047eef19944SJakub Matěna /* Can we merge the predecessor? */ 10481da177e4SLinus Torvalds if (prev && prev->vm_end == addr && 10491da177e4SLinus Torvalds mpol_equal(vma_policy(prev), policy) && 10501da177e4SLinus Torvalds can_vma_merge_after(prev, vm_flags, 105119a809afSAndrea Arcangeli anon_vma, file, pgoff, 10529a10064fSColin Cross vm_userfaultfd_ctx, anon_name)) { 1053eef19944SJakub Matěna merge_prev = true; 10541da177e4SLinus Torvalds } 1055eef19944SJakub Matěna /* Can we merge the successor? */ 10561da177e4SLinus Torvalds if (next && end == next->vm_start && 10571da177e4SLinus Torvalds mpol_equal(policy, vma_policy(next)) && 10581da177e4SLinus Torvalds can_vma_merge_before(next, vm_flags, 105919a809afSAndrea Arcangeli anon_vma, file, pgoff+pglen, 10609a10064fSColin Cross vm_userfaultfd_ctx, anon_name)) { 1061eef19944SJakub Matěna merge_next = true; 1062eef19944SJakub Matěna } 1063eef19944SJakub Matěna /* Can we merge both the predecessor and the successor? */ 1064eef19944SJakub Matěna if (merge_prev && merge_next && 1065eef19944SJakub Matěna is_mergeable_anon_vma(prev->anon_vma, 1066eef19944SJakub Matěna next->anon_vma, NULL)) { /* cases 1, 6 */ 1067eef19944SJakub Matěna err = __vma_adjust(prev, prev->vm_start, 1068eef19944SJakub Matěna next->vm_end, prev->vm_pgoff, NULL, 1069eef19944SJakub Matěna prev); 1070eef19944SJakub Matěna res = prev; 1071eef19944SJakub Matěna } else if (merge_prev) { /* cases 2, 5, 7 */ 1072eef19944SJakub Matěna err = __vma_adjust(prev, prev->vm_start, 1073eef19944SJakub Matěna end, prev->vm_pgoff, NULL, prev); 1074eef19944SJakub Matěna res = prev; 1075eef19944SJakub Matěna } else if (merge_next) { 10761da177e4SLinus Torvalds if (prev && addr < prev->vm_end) /* case 4 */ 1077e86f15eeSAndrea Arcangeli err = __vma_adjust(prev, prev->vm_start, 1078e86f15eeSAndrea Arcangeli addr, prev->vm_pgoff, NULL, next); 1079eef19944SJakub Matěna else /* cases 3, 8 */ 1080eef19944SJakub Matěna err = __vma_adjust(mid, addr, next->vm_end, 1081e86f15eeSAndrea Arcangeli next->vm_pgoff - pglen, NULL, next); 1082eef19944SJakub Matěna res = next; 10831da177e4SLinus Torvalds } 10841da177e4SLinus Torvalds 1085eef19944SJakub Matěna /* 1086eef19944SJakub Matěna * Cannot merge with predecessor or successor or error in __vma_adjust? 1087eef19944SJakub Matěna */ 1088eef19944SJakub Matěna if (err) 10891da177e4SLinus Torvalds return NULL; 1090eef19944SJakub Matěna khugepaged_enter_vma(res, vm_flags); 1091eef19944SJakub Matěna return res; 10921da177e4SLinus Torvalds } 10931da177e4SLinus Torvalds 10941da177e4SLinus Torvalds /* 1095b4f315b4SEthon Paul * Rough compatibility check to quickly see if it's even worth looking 1096d0e9fe17SLinus Torvalds * at sharing an anon_vma. 1097d0e9fe17SLinus Torvalds * 1098d0e9fe17SLinus Torvalds * They need to have the same vm_file, and the flags can only differ 1099d0e9fe17SLinus Torvalds * in things that mprotect may change. 1100d0e9fe17SLinus Torvalds * 1101d0e9fe17SLinus Torvalds * NOTE! The fact that we share an anon_vma doesn't _have_ to mean that 1102d0e9fe17SLinus Torvalds * we can merge the two vma's. For example, we refuse to merge a vma if 1103d0e9fe17SLinus Torvalds * there is a vm_ops->close() function, because that indicates that the 1104d0e9fe17SLinus Torvalds * driver is doing some kind of reference counting. But that doesn't 1105d0e9fe17SLinus Torvalds * really matter for the anon_vma sharing case. 1106d0e9fe17SLinus Torvalds */ 1107d0e9fe17SLinus Torvalds static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *b) 1108d0e9fe17SLinus Torvalds { 1109d0e9fe17SLinus Torvalds return a->vm_end == b->vm_start && 1110d0e9fe17SLinus Torvalds mpol_equal(vma_policy(a), vma_policy(b)) && 1111d0e9fe17SLinus Torvalds a->vm_file == b->vm_file && 11126cb4d9a2SAnshuman Khandual !((a->vm_flags ^ b->vm_flags) & ~(VM_ACCESS_FLAGS | VM_SOFTDIRTY)) && 1113d0e9fe17SLinus Torvalds b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT); 1114d0e9fe17SLinus Torvalds } 1115d0e9fe17SLinus Torvalds 1116d0e9fe17SLinus Torvalds /* 1117d0e9fe17SLinus Torvalds * Do some basic sanity checking to see if we can re-use the anon_vma 1118d0e9fe17SLinus Torvalds * from 'old'. The 'a'/'b' vma's are in VM order - one of them will be 1119d0e9fe17SLinus Torvalds * the same as 'old', the other will be the new one that is trying 1120d0e9fe17SLinus Torvalds * to share the anon_vma. 1121d0e9fe17SLinus Torvalds * 11225b449489SFlorian Rommel * NOTE! This runs with mmap_lock held for reading, so it is possible that 1123d0e9fe17SLinus Torvalds * the anon_vma of 'old' is concurrently in the process of being set up 1124d0e9fe17SLinus Torvalds * by another page fault trying to merge _that_. But that's ok: if it 1125d0e9fe17SLinus Torvalds * is being set up, that automatically means that it will be a singleton 1126d0e9fe17SLinus Torvalds * acceptable for merging, so we can do all of this optimistically. But 11274db0c3c2SJason Low * we do that READ_ONCE() to make sure that we never re-load the pointer. 1128d0e9fe17SLinus Torvalds * 1129d0e9fe17SLinus Torvalds * IOW: that the "list_is_singular()" test on the anon_vma_chain only 1130d0e9fe17SLinus Torvalds * matters for the 'stable anon_vma' case (ie the thing we want to avoid 1131d0e9fe17SLinus Torvalds * is to return an anon_vma that is "complex" due to having gone through 1132d0e9fe17SLinus Torvalds * a fork). 1133d0e9fe17SLinus Torvalds * 1134d0e9fe17SLinus Torvalds * We also make sure that the two vma's are compatible (adjacent, 1135d0e9fe17SLinus Torvalds * and with the same memory policies). That's all stable, even with just 11365b449489SFlorian Rommel * a read lock on the mmap_lock. 1137d0e9fe17SLinus Torvalds */ 1138d0e9fe17SLinus Torvalds static struct anon_vma *reusable_anon_vma(struct vm_area_struct *old, struct vm_area_struct *a, struct vm_area_struct *b) 1139d0e9fe17SLinus Torvalds { 1140d0e9fe17SLinus Torvalds if (anon_vma_compatible(a, b)) { 11414db0c3c2SJason Low struct anon_vma *anon_vma = READ_ONCE(old->anon_vma); 1142d0e9fe17SLinus Torvalds 1143d0e9fe17SLinus Torvalds if (anon_vma && list_is_singular(&old->anon_vma_chain)) 1144d0e9fe17SLinus Torvalds return anon_vma; 1145d0e9fe17SLinus Torvalds } 1146d0e9fe17SLinus Torvalds return NULL; 1147d0e9fe17SLinus Torvalds } 1148d0e9fe17SLinus Torvalds 1149d0e9fe17SLinus Torvalds /* 11501da177e4SLinus Torvalds * find_mergeable_anon_vma is used by anon_vma_prepare, to check 11511da177e4SLinus Torvalds * neighbouring vmas for a suitable anon_vma, before it goes off 11521da177e4SLinus Torvalds * to allocate a new anon_vma. It checks because a repetitive 11531da177e4SLinus Torvalds * sequence of mprotects and faults may otherwise lead to distinct 11541da177e4SLinus Torvalds * anon_vmas being allocated, preventing vma merge in subsequent 11551da177e4SLinus Torvalds * mprotect. 11561da177e4SLinus Torvalds */ 11571da177e4SLinus Torvalds struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma) 11581da177e4SLinus Torvalds { 1159763ecb03SLiam R. Howlett MA_STATE(mas, &vma->vm_mm->mm_mt, vma->vm_end, vma->vm_end); 1160a67c8caaSMiaohe Lin struct anon_vma *anon_vma = NULL; 1161763ecb03SLiam R. Howlett struct vm_area_struct *prev, *next; 11621da177e4SLinus Torvalds 1163a67c8caaSMiaohe Lin /* Try next first. */ 1164763ecb03SLiam R. Howlett next = mas_walk(&mas); 1165763ecb03SLiam R. Howlett if (next) { 1166763ecb03SLiam R. Howlett anon_vma = reusable_anon_vma(next, vma, next); 1167d0e9fe17SLinus Torvalds if (anon_vma) 1168d0e9fe17SLinus Torvalds return anon_vma; 1169a67c8caaSMiaohe Lin } 11701da177e4SLinus Torvalds 1171763ecb03SLiam R. Howlett prev = mas_prev(&mas, 0); 1172763ecb03SLiam R. Howlett VM_BUG_ON_VMA(prev != vma, vma); 1173763ecb03SLiam R. Howlett prev = mas_prev(&mas, 0); 1174a67c8caaSMiaohe Lin /* Try prev next. */ 1175763ecb03SLiam R. Howlett if (prev) 1176763ecb03SLiam R. Howlett anon_vma = reusable_anon_vma(prev, prev, vma); 1177a67c8caaSMiaohe Lin 11781da177e4SLinus Torvalds /* 1179a67c8caaSMiaohe Lin * We might reach here with anon_vma == NULL if we can't find 1180a67c8caaSMiaohe Lin * any reusable anon_vma. 11811da177e4SLinus Torvalds * There's no absolute need to look only at touching neighbours: 11821da177e4SLinus Torvalds * we could search further afield for "compatible" anon_vmas. 11831da177e4SLinus Torvalds * But it would probably just be a waste of time searching, 11841da177e4SLinus Torvalds * or lead to too many vmas hanging off the same anon_vma. 11851da177e4SLinus Torvalds * We're trying to allow mprotect remerging later on, 11861da177e4SLinus Torvalds * not trying to minimize memory used for anon_vmas. 11871da177e4SLinus Torvalds */ 1188a67c8caaSMiaohe Lin return anon_vma; 11891da177e4SLinus Torvalds } 11901da177e4SLinus Torvalds 11911da177e4SLinus Torvalds /* 119240401530SAl Viro * If a hint addr is less than mmap_min_addr change hint to be as 119340401530SAl Viro * low as possible but still greater than mmap_min_addr 119440401530SAl Viro */ 119540401530SAl Viro static inline unsigned long round_hint_to_min(unsigned long hint) 119640401530SAl Viro { 119740401530SAl Viro hint &= PAGE_MASK; 119840401530SAl Viro if (((void *)hint != NULL) && 119940401530SAl Viro (hint < mmap_min_addr)) 120040401530SAl Viro return PAGE_ALIGN(mmap_min_addr); 120140401530SAl Viro return hint; 120240401530SAl Viro } 120340401530SAl Viro 12046aeb2542SMike Rapoport int mlock_future_check(struct mm_struct *mm, unsigned long flags, 1205363ee17fSDavidlohr Bueso unsigned long len) 1206363ee17fSDavidlohr Bueso { 1207363ee17fSDavidlohr Bueso unsigned long locked, lock_limit; 1208363ee17fSDavidlohr Bueso 1209363ee17fSDavidlohr Bueso /* mlock MCL_FUTURE? */ 1210363ee17fSDavidlohr Bueso if (flags & VM_LOCKED) { 1211363ee17fSDavidlohr Bueso locked = len >> PAGE_SHIFT; 1212363ee17fSDavidlohr Bueso locked += mm->locked_vm; 1213363ee17fSDavidlohr Bueso lock_limit = rlimit(RLIMIT_MEMLOCK); 1214363ee17fSDavidlohr Bueso lock_limit >>= PAGE_SHIFT; 1215363ee17fSDavidlohr Bueso if (locked > lock_limit && !capable(CAP_IPC_LOCK)) 1216363ee17fSDavidlohr Bueso return -EAGAIN; 1217363ee17fSDavidlohr Bueso } 1218363ee17fSDavidlohr Bueso return 0; 1219363ee17fSDavidlohr Bueso } 1220363ee17fSDavidlohr Bueso 1221be83bbf8SLinus Torvalds static inline u64 file_mmap_size_max(struct file *file, struct inode *inode) 1222be83bbf8SLinus Torvalds { 1223be83bbf8SLinus Torvalds if (S_ISREG(inode->i_mode)) 1224423913adSLinus Torvalds return MAX_LFS_FILESIZE; 1225be83bbf8SLinus Torvalds 1226be83bbf8SLinus Torvalds if (S_ISBLK(inode->i_mode)) 1227be83bbf8SLinus Torvalds return MAX_LFS_FILESIZE; 1228be83bbf8SLinus Torvalds 122976f34950SIvan Khoronzhuk if (S_ISSOCK(inode->i_mode)) 123076f34950SIvan Khoronzhuk return MAX_LFS_FILESIZE; 123176f34950SIvan Khoronzhuk 1232be83bbf8SLinus Torvalds /* Special "we do even unsigned file positions" case */ 1233be83bbf8SLinus Torvalds if (file->f_mode & FMODE_UNSIGNED_OFFSET) 1234be83bbf8SLinus Torvalds return 0; 1235be83bbf8SLinus Torvalds 1236be83bbf8SLinus Torvalds /* Yes, random drivers might want more. But I'm tired of buggy drivers */ 1237be83bbf8SLinus Torvalds return ULONG_MAX; 1238be83bbf8SLinus Torvalds } 1239be83bbf8SLinus Torvalds 1240be83bbf8SLinus Torvalds static inline bool file_mmap_ok(struct file *file, struct inode *inode, 1241be83bbf8SLinus Torvalds unsigned long pgoff, unsigned long len) 1242be83bbf8SLinus Torvalds { 1243be83bbf8SLinus Torvalds u64 maxsize = file_mmap_size_max(file, inode); 1244be83bbf8SLinus Torvalds 1245be83bbf8SLinus Torvalds if (maxsize && len > maxsize) 1246be83bbf8SLinus Torvalds return false; 1247be83bbf8SLinus Torvalds maxsize -= len; 1248be83bbf8SLinus Torvalds if (pgoff > maxsize >> PAGE_SHIFT) 1249be83bbf8SLinus Torvalds return false; 1250be83bbf8SLinus Torvalds return true; 1251be83bbf8SLinus Torvalds } 1252be83bbf8SLinus Torvalds 125340401530SAl Viro /* 12543e4e28c5SMichel Lespinasse * The caller must write-lock current->mm->mmap_lock. 12551da177e4SLinus Torvalds */ 12561fcfd8dbSOleg Nesterov unsigned long do_mmap(struct file *file, unsigned long addr, 12571da177e4SLinus Torvalds unsigned long len, unsigned long prot, 125845e55300SPeter Collingbourne unsigned long flags, unsigned long pgoff, 125945e55300SPeter Collingbourne unsigned long *populate, struct list_head *uf) 12601da177e4SLinus Torvalds { 12611da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 126245e55300SPeter Collingbourne vm_flags_t vm_flags; 126362b5f7d0SDave Hansen int pkey = 0; 12641da177e4SLinus Torvalds 1265524e00b3SLiam R. Howlett validate_mm(mm); 126641badc15SMichel Lespinasse *populate = 0; 1267bebeb3d6SMichel Lespinasse 1268e37609bbSPiotr Kwapulinski if (!len) 1269e37609bbSPiotr Kwapulinski return -EINVAL; 1270e37609bbSPiotr Kwapulinski 12711da177e4SLinus Torvalds /* 12721da177e4SLinus Torvalds * Does the application expect PROT_READ to imply PROT_EXEC? 12731da177e4SLinus Torvalds * 12741da177e4SLinus Torvalds * (the exception is when the underlying filesystem is noexec 12751da177e4SLinus Torvalds * mounted, in which case we dont add PROT_EXEC.) 12761da177e4SLinus Torvalds */ 12771da177e4SLinus Torvalds if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) 127890f8572bSEric W. Biederman if (!(file && path_noexec(&file->f_path))) 12791da177e4SLinus Torvalds prot |= PROT_EXEC; 12801da177e4SLinus Torvalds 1281a4ff8e86SMichal Hocko /* force arch specific MAP_FIXED handling in get_unmapped_area */ 1282a4ff8e86SMichal Hocko if (flags & MAP_FIXED_NOREPLACE) 1283a4ff8e86SMichal Hocko flags |= MAP_FIXED; 1284a4ff8e86SMichal Hocko 12857cd94146SEric Paris if (!(flags & MAP_FIXED)) 12867cd94146SEric Paris addr = round_hint_to_min(addr); 12877cd94146SEric Paris 12881da177e4SLinus Torvalds /* Careful about overflows.. */ 12891da177e4SLinus Torvalds len = PAGE_ALIGN(len); 12909206de95SAl Viro if (!len) 12911da177e4SLinus Torvalds return -ENOMEM; 12921da177e4SLinus Torvalds 12931da177e4SLinus Torvalds /* offset overflow? */ 12941da177e4SLinus Torvalds if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) 12951da177e4SLinus Torvalds return -EOVERFLOW; 12961da177e4SLinus Torvalds 12971da177e4SLinus Torvalds /* Too many mappings? */ 12981da177e4SLinus Torvalds if (mm->map_count > sysctl_max_map_count) 12991da177e4SLinus Torvalds return -ENOMEM; 13001da177e4SLinus Torvalds 13011da177e4SLinus Torvalds /* Obtain the address to map to. we verify (or select) it and ensure 13021da177e4SLinus Torvalds * that it represents a valid section of the address space. 13031da177e4SLinus Torvalds */ 13041da177e4SLinus Torvalds addr = get_unmapped_area(file, addr, len, pgoff, flags); 1305ff68dac6SGaowei Pu if (IS_ERR_VALUE(addr)) 13061da177e4SLinus Torvalds return addr; 13071da177e4SLinus Torvalds 1308a4ff8e86SMichal Hocko if (flags & MAP_FIXED_NOREPLACE) { 130935e43c5fSLiam Howlett if (find_vma_intersection(mm, addr, addr + len)) 1310a4ff8e86SMichal Hocko return -EEXIST; 1311a4ff8e86SMichal Hocko } 1312a4ff8e86SMichal Hocko 131362b5f7d0SDave Hansen if (prot == PROT_EXEC) { 131462b5f7d0SDave Hansen pkey = execute_only_pkey(mm); 131562b5f7d0SDave Hansen if (pkey < 0) 131662b5f7d0SDave Hansen pkey = 0; 131762b5f7d0SDave Hansen } 131862b5f7d0SDave Hansen 13191da177e4SLinus Torvalds /* Do simple checking here so the lower-level routines won't have 13201da177e4SLinus Torvalds * to. we assume access permissions have been handled by the open 13211da177e4SLinus Torvalds * of the memory object, so we don't do any here. 13221da177e4SLinus Torvalds */ 132345e55300SPeter Collingbourne vm_flags = calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) | 13241da177e4SLinus Torvalds mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; 13251da177e4SLinus Torvalds 1326cdf7b341SHuang Shijie if (flags & MAP_LOCKED) 13271da177e4SLinus Torvalds if (!can_do_mlock()) 13281da177e4SLinus Torvalds return -EPERM; 1329ba470de4SRik van Riel 1330363ee17fSDavidlohr Bueso if (mlock_future_check(mm, vm_flags, len)) 13311da177e4SLinus Torvalds return -EAGAIN; 13321da177e4SLinus Torvalds 13331da177e4SLinus Torvalds if (file) { 1334077bf22bSOleg Nesterov struct inode *inode = file_inode(file); 13351c972597SDan Williams unsigned long flags_mask; 13361c972597SDan Williams 1337be83bbf8SLinus Torvalds if (!file_mmap_ok(file, inode, pgoff, len)) 1338be83bbf8SLinus Torvalds return -EOVERFLOW; 1339be83bbf8SLinus Torvalds 13401c972597SDan Williams flags_mask = LEGACY_MAP_MASK | file->f_op->mmap_supported_flags; 1341077bf22bSOleg Nesterov 13421da177e4SLinus Torvalds switch (flags & MAP_TYPE) { 13431da177e4SLinus Torvalds case MAP_SHARED: 13441c972597SDan Williams /* 13451c972597SDan Williams * Force use of MAP_SHARED_VALIDATE with non-legacy 13461c972597SDan Williams * flags. E.g. MAP_SYNC is dangerous to use with 13471c972597SDan Williams * MAP_SHARED as you don't know which consistency model 13481c972597SDan Williams * you will get. We silently ignore unsupported flags 13491c972597SDan Williams * with MAP_SHARED to preserve backward compatibility. 13501c972597SDan Williams */ 13511c972597SDan Williams flags &= LEGACY_MAP_MASK; 1352e4a9bc58SJoe Perches fallthrough; 13531c972597SDan Williams case MAP_SHARED_VALIDATE: 13541c972597SDan Williams if (flags & ~flags_mask) 13551c972597SDan Williams return -EOPNOTSUPP; 1356dc617f29SDarrick J. Wong if (prot & PROT_WRITE) { 1357dc617f29SDarrick J. Wong if (!(file->f_mode & FMODE_WRITE)) 13581da177e4SLinus Torvalds return -EACCES; 1359dc617f29SDarrick J. Wong if (IS_SWAPFILE(file->f_mapping->host)) 1360dc617f29SDarrick J. Wong return -ETXTBSY; 1361dc617f29SDarrick J. Wong } 13621da177e4SLinus Torvalds 13631da177e4SLinus Torvalds /* 13641da177e4SLinus Torvalds * Make sure we don't allow writing to an append-only 13651da177e4SLinus Torvalds * file.. 13661da177e4SLinus Torvalds */ 13671da177e4SLinus Torvalds if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE)) 13681da177e4SLinus Torvalds return -EACCES; 13691da177e4SLinus Torvalds 13701da177e4SLinus Torvalds vm_flags |= VM_SHARED | VM_MAYSHARE; 13711da177e4SLinus Torvalds if (!(file->f_mode & FMODE_WRITE)) 13721da177e4SLinus Torvalds vm_flags &= ~(VM_MAYWRITE | VM_SHARED); 1373e4a9bc58SJoe Perches fallthrough; 13741da177e4SLinus Torvalds case MAP_PRIVATE: 13751da177e4SLinus Torvalds if (!(file->f_mode & FMODE_READ)) 13761da177e4SLinus Torvalds return -EACCES; 137790f8572bSEric W. Biederman if (path_noexec(&file->f_path)) { 137880c5606cSLinus Torvalds if (vm_flags & VM_EXEC) 137980c5606cSLinus Torvalds return -EPERM; 138080c5606cSLinus Torvalds vm_flags &= ~VM_MAYEXEC; 138180c5606cSLinus Torvalds } 138280c5606cSLinus Torvalds 138372c2d531SAl Viro if (!file->f_op->mmap) 138480c5606cSLinus Torvalds return -ENODEV; 1385b2c56e4fSOleg Nesterov if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) 1386b2c56e4fSOleg Nesterov return -EINVAL; 13871da177e4SLinus Torvalds break; 13881da177e4SLinus Torvalds 13891da177e4SLinus Torvalds default: 13901da177e4SLinus Torvalds return -EINVAL; 13911da177e4SLinus Torvalds } 13921da177e4SLinus Torvalds } else { 13931da177e4SLinus Torvalds switch (flags & MAP_TYPE) { 13941da177e4SLinus Torvalds case MAP_SHARED: 1395b2c56e4fSOleg Nesterov if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) 1396b2c56e4fSOleg Nesterov return -EINVAL; 1397ce363942STejun Heo /* 1398ce363942STejun Heo * Ignore pgoff. 1399ce363942STejun Heo */ 1400ce363942STejun Heo pgoff = 0; 14011da177e4SLinus Torvalds vm_flags |= VM_SHARED | VM_MAYSHARE; 14021da177e4SLinus Torvalds break; 14031da177e4SLinus Torvalds case MAP_PRIVATE: 14041da177e4SLinus Torvalds /* 14051da177e4SLinus Torvalds * Set pgoff according to addr for anon_vma. 14061da177e4SLinus Torvalds */ 14071da177e4SLinus Torvalds pgoff = addr >> PAGE_SHIFT; 14081da177e4SLinus Torvalds break; 14091da177e4SLinus Torvalds default: 14101da177e4SLinus Torvalds return -EINVAL; 14111da177e4SLinus Torvalds } 14121da177e4SLinus Torvalds } 14131da177e4SLinus Torvalds 1414c22c0d63SMichel Lespinasse /* 1415c22c0d63SMichel Lespinasse * Set 'VM_NORESERVE' if we should not account for the 1416c22c0d63SMichel Lespinasse * memory use of this mapping. 1417c22c0d63SMichel Lespinasse */ 1418c22c0d63SMichel Lespinasse if (flags & MAP_NORESERVE) { 1419c22c0d63SMichel Lespinasse /* We honor MAP_NORESERVE if allowed to overcommit */ 1420c22c0d63SMichel Lespinasse if (sysctl_overcommit_memory != OVERCOMMIT_NEVER) 1421c22c0d63SMichel Lespinasse vm_flags |= VM_NORESERVE; 1422c22c0d63SMichel Lespinasse 1423c22c0d63SMichel Lespinasse /* hugetlb applies strict overcommit unless MAP_NORESERVE */ 1424c22c0d63SMichel Lespinasse if (file && is_file_hugepages(file)) 1425c22c0d63SMichel Lespinasse vm_flags |= VM_NORESERVE; 1426c22c0d63SMichel Lespinasse } 1427c22c0d63SMichel Lespinasse 1428897ab3e0SMike Rapoport addr = mmap_region(file, addr, len, vm_flags, pgoff, uf); 142909a9f1d2SMichel Lespinasse if (!IS_ERR_VALUE(addr) && 143009a9f1d2SMichel Lespinasse ((vm_flags & VM_LOCKED) || 143109a9f1d2SMichel Lespinasse (flags & (MAP_POPULATE | MAP_NONBLOCK)) == MAP_POPULATE)) 143241badc15SMichel Lespinasse *populate = len; 1433bebeb3d6SMichel Lespinasse return addr; 14340165ab44SMiklos Szeredi } 14356be5ceb0SLinus Torvalds 1436a90f590aSDominik Brodowski unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len, 1437a90f590aSDominik Brodowski unsigned long prot, unsigned long flags, 1438a90f590aSDominik Brodowski unsigned long fd, unsigned long pgoff) 143966f0dc48SHugh Dickins { 144066f0dc48SHugh Dickins struct file *file = NULL; 14411e3ee14bSChen Gang unsigned long retval; 144266f0dc48SHugh Dickins 144366f0dc48SHugh Dickins if (!(flags & MAP_ANONYMOUS)) { 1444120a795dSAl Viro audit_mmap_fd(fd, flags); 144566f0dc48SHugh Dickins file = fget(fd); 144666f0dc48SHugh Dickins if (!file) 14471e3ee14bSChen Gang return -EBADF; 14487bba8f0eSZhen Lei if (is_file_hugepages(file)) { 1449af73e4d9SNaoya Horiguchi len = ALIGN(len, huge_page_size(hstate_file(file))); 14507bba8f0eSZhen Lei } else if (unlikely(flags & MAP_HUGETLB)) { 1451493af578SJörn Engel retval = -EINVAL; 1452493af578SJörn Engel goto out_fput; 14537bba8f0eSZhen Lei } 145466f0dc48SHugh Dickins } else if (flags & MAP_HUGETLB) { 1455c103a4dcSAndrew Morton struct hstate *hs; 1456af73e4d9SNaoya Horiguchi 145720ac2893SAnshuman Khandual hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); 1458091d0d55SLi Zefan if (!hs) 1459091d0d55SLi Zefan return -EINVAL; 1460091d0d55SLi Zefan 1461091d0d55SLi Zefan len = ALIGN(len, huge_page_size(hs)); 146266f0dc48SHugh Dickins /* 146366f0dc48SHugh Dickins * VM_NORESERVE is used because the reservations will be 146466f0dc48SHugh Dickins * taken when vm_ops->mmap() is called 146566f0dc48SHugh Dickins */ 1466af73e4d9SNaoya Horiguchi file = hugetlb_file_setup(HUGETLB_ANON_FILE, len, 146742d7395fSAndi Kleen VM_NORESERVE, 146883c1fd76Szhangyiru HUGETLB_ANONHUGE_INODE, 146942d7395fSAndi Kleen (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); 147066f0dc48SHugh Dickins if (IS_ERR(file)) 147166f0dc48SHugh Dickins return PTR_ERR(file); 147266f0dc48SHugh Dickins } 147366f0dc48SHugh Dickins 14749fbeb5abSMichal Hocko retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff); 1475493af578SJörn Engel out_fput: 147666f0dc48SHugh Dickins if (file) 147766f0dc48SHugh Dickins fput(file); 147866f0dc48SHugh Dickins return retval; 147966f0dc48SHugh Dickins } 148066f0dc48SHugh Dickins 1481a90f590aSDominik Brodowski SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, 1482a90f590aSDominik Brodowski unsigned long, prot, unsigned long, flags, 1483a90f590aSDominik Brodowski unsigned long, fd, unsigned long, pgoff) 1484a90f590aSDominik Brodowski { 1485a90f590aSDominik Brodowski return ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff); 1486a90f590aSDominik Brodowski } 1487a90f590aSDominik Brodowski 1488a4679373SChristoph Hellwig #ifdef __ARCH_WANT_SYS_OLD_MMAP 1489a4679373SChristoph Hellwig struct mmap_arg_struct { 1490a4679373SChristoph Hellwig unsigned long addr; 1491a4679373SChristoph Hellwig unsigned long len; 1492a4679373SChristoph Hellwig unsigned long prot; 1493a4679373SChristoph Hellwig unsigned long flags; 1494a4679373SChristoph Hellwig unsigned long fd; 1495a4679373SChristoph Hellwig unsigned long offset; 1496a4679373SChristoph Hellwig }; 1497a4679373SChristoph Hellwig 1498a4679373SChristoph Hellwig SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg) 1499a4679373SChristoph Hellwig { 1500a4679373SChristoph Hellwig struct mmap_arg_struct a; 1501a4679373SChristoph Hellwig 1502a4679373SChristoph Hellwig if (copy_from_user(&a, arg, sizeof(a))) 1503a4679373SChristoph Hellwig return -EFAULT; 1504de1741a1SAlexander Kuleshov if (offset_in_page(a.offset)) 1505a4679373SChristoph Hellwig return -EINVAL; 1506a4679373SChristoph Hellwig 1507a90f590aSDominik Brodowski return ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, 1508a4679373SChristoph Hellwig a.offset >> PAGE_SHIFT); 1509a4679373SChristoph Hellwig } 1510a4679373SChristoph Hellwig #endif /* __ARCH_WANT_SYS_OLD_MMAP */ 1511a4679373SChristoph Hellwig 15124e950f6fSAlexey Dobriyan /* 15138bb4e7a2SWei Yang * Some shared mappings will want the pages marked read-only 15144e950f6fSAlexey Dobriyan * to track write events. If so, we'll downgrade vm_page_prot 15154e950f6fSAlexey Dobriyan * to the private version (using protection_map[] without the 15164e950f6fSAlexey Dobriyan * VM_SHARED bit). 15174e950f6fSAlexey Dobriyan */ 15186d2329f8SAndrea Arcangeli int vma_wants_writenotify(struct vm_area_struct *vma, pgprot_t vm_page_prot) 15194e950f6fSAlexey Dobriyan { 1520ca16d140SKOSAKI Motohiro vm_flags_t vm_flags = vma->vm_flags; 15218a04446aSKirill A. Shutemov const struct vm_operations_struct *vm_ops = vma->vm_ops; 15224e950f6fSAlexey Dobriyan 15234e950f6fSAlexey Dobriyan /* If it was private or non-writable, the write bit is already clear */ 15244e950f6fSAlexey Dobriyan if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED))) 15254e950f6fSAlexey Dobriyan return 0; 15264e950f6fSAlexey Dobriyan 15274e950f6fSAlexey Dobriyan /* The backer wishes to know when pages are first written to? */ 15288a04446aSKirill A. Shutemov if (vm_ops && (vm_ops->page_mkwrite || vm_ops->pfn_mkwrite)) 15294e950f6fSAlexey Dobriyan return 1; 15304e950f6fSAlexey Dobriyan 153164e45507SPeter Feiner /* The open routine did something to the protections that pgprot_modify 153264e45507SPeter Feiner * won't preserve? */ 15336d2329f8SAndrea Arcangeli if (pgprot_val(vm_page_prot) != 15346d2329f8SAndrea Arcangeli pgprot_val(vm_pgprot_modify(vm_page_prot, vm_flags))) 15354e950f6fSAlexey Dobriyan return 0; 15364e950f6fSAlexey Dobriyan 1537f96f7a40SDavid Hildenbrand /* 1538f96f7a40SDavid Hildenbrand * Do we need to track softdirty? hugetlb does not support softdirty 1539f96f7a40SDavid Hildenbrand * tracking yet. 1540f96f7a40SDavid Hildenbrand */ 1541f96f7a40SDavid Hildenbrand if (vma_soft_dirty_enabled(vma) && !is_vm_hugetlb_page(vma)) 154264e45507SPeter Feiner return 1; 154364e45507SPeter Feiner 154451d3d5ebSDavid Hildenbrand /* Do we need write faults for uffd-wp tracking? */ 154551d3d5ebSDavid Hildenbrand if (userfaultfd_wp(vma)) 154651d3d5ebSDavid Hildenbrand return 1; 154751d3d5ebSDavid Hildenbrand 15484e950f6fSAlexey Dobriyan /* Specialty mapping? */ 15494b6e1e37SKonstantin Khlebnikov if (vm_flags & VM_PFNMAP) 15504e950f6fSAlexey Dobriyan return 0; 15514e950f6fSAlexey Dobriyan 15524e950f6fSAlexey Dobriyan /* Can the mapping track the dirty pages? */ 15534e950f6fSAlexey Dobriyan return vma->vm_file && vma->vm_file->f_mapping && 1554f56753acSChristoph Hellwig mapping_can_writeback(vma->vm_file->f_mapping); 15554e950f6fSAlexey Dobriyan } 15564e950f6fSAlexey Dobriyan 1557fc8744adSLinus Torvalds /* 1558fc8744adSLinus Torvalds * We account for memory if it's a private writeable mapping, 15595a6fe125SMel Gorman * not hugepages and VM_NORESERVE wasn't set. 1560fc8744adSLinus Torvalds */ 1561ca16d140SKOSAKI Motohiro static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags) 1562fc8744adSLinus Torvalds { 15635a6fe125SMel Gorman /* 15645a6fe125SMel Gorman * hugetlb has its own accounting separate from the core VM 15655a6fe125SMel Gorman * VM_HUGETLB may not be set yet so we cannot check for that flag. 15665a6fe125SMel Gorman */ 15675a6fe125SMel Gorman if (file && is_file_hugepages(file)) 15685a6fe125SMel Gorman return 0; 15695a6fe125SMel Gorman 1570fc8744adSLinus Torvalds return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE; 1571fc8744adSLinus Torvalds } 1572fc8744adSLinus Torvalds 15733499a131SLiam R. Howlett /** 15743499a131SLiam R. Howlett * unmapped_area() - Find an area between the low_limit and the high_limit with 15753499a131SLiam R. Howlett * the correct alignment and offset, all from @info. Note: current->mm is used 15763499a131SLiam R. Howlett * for the search. 15773499a131SLiam R. Howlett * 157882b24936SVernon Yang * @info: The unmapped area information including the range [low_limit - 157982b24936SVernon Yang * high_limit), the alignment offset and mask. 15803499a131SLiam R. Howlett * 15813499a131SLiam R. Howlett * Return: A memory address or -ENOMEM. 15823499a131SLiam R. Howlett */ 1583baceaf1cSJaewon Kim static unsigned long unmapped_area(struct vm_unmapped_area_info *info) 1584db4fbfb9SMichel Lespinasse { 15853499a131SLiam R. Howlett unsigned long length, gap; 1586db4fbfb9SMichel Lespinasse 15873499a131SLiam R. Howlett MA_STATE(mas, ¤t->mm->mm_mt, 0, 0); 1588db4fbfb9SMichel Lespinasse 1589db4fbfb9SMichel Lespinasse /* Adjust search length to account for worst case alignment overhead */ 1590db4fbfb9SMichel Lespinasse length = info->length + info->align_mask; 1591db4fbfb9SMichel Lespinasse if (length < info->length) 1592db4fbfb9SMichel Lespinasse return -ENOMEM; 1593db4fbfb9SMichel Lespinasse 15943499a131SLiam R. Howlett if (mas_empty_area(&mas, info->low_limit, info->high_limit - 1, 15953499a131SLiam R. Howlett length)) 15963499a131SLiam R. Howlett return -ENOMEM; 15973499a131SLiam R. Howlett 1598d4af56c5SLiam R. Howlett gap = mas.index; 1599d4af56c5SLiam R. Howlett gap += (info->align_offset - gap) & info->align_mask; 16003499a131SLiam R. Howlett return gap; 1601db4fbfb9SMichel Lespinasse } 1602db4fbfb9SMichel Lespinasse 16033499a131SLiam R. Howlett /** 16043499a131SLiam R. Howlett * unmapped_area_topdown() - Find an area between the low_limit and the 160582b24936SVernon Yang * high_limit with the correct alignment and offset at the highest available 16063499a131SLiam R. Howlett * address, all from @info. Note: current->mm is used for the search. 16073499a131SLiam R. Howlett * 160882b24936SVernon Yang * @info: The unmapped area information including the range [low_limit - 160982b24936SVernon Yang * high_limit), the alignment offset and mask. 16103499a131SLiam R. Howlett * 16113499a131SLiam R. Howlett * Return: A memory address or -ENOMEM. 16123499a131SLiam R. Howlett */ 1613baceaf1cSJaewon Kim static unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info) 1614db4fbfb9SMichel Lespinasse { 16153499a131SLiam R. Howlett unsigned long length, gap; 1616d4af56c5SLiam R. Howlett 16173499a131SLiam R. Howlett MA_STATE(mas, ¤t->mm->mm_mt, 0, 0); 1618db4fbfb9SMichel Lespinasse /* Adjust search length to account for worst case alignment overhead */ 1619db4fbfb9SMichel Lespinasse length = info->length + info->align_mask; 1620db4fbfb9SMichel Lespinasse if (length < info->length) 1621db4fbfb9SMichel Lespinasse return -ENOMEM; 1622db4fbfb9SMichel Lespinasse 16233499a131SLiam R. Howlett if (mas_empty_area_rev(&mas, info->low_limit, info->high_limit - 1, 16243499a131SLiam R. Howlett length)) 16253499a131SLiam R. Howlett return -ENOMEM; 16263499a131SLiam R. Howlett 1627d4af56c5SLiam R. Howlett gap = mas.last + 1 - info->length; 1628d4af56c5SLiam R. Howlett gap -= (gap - info->align_offset) & info->align_mask; 16293499a131SLiam R. Howlett return gap; 1630db4fbfb9SMichel Lespinasse } 1631db4fbfb9SMichel Lespinasse 1632baceaf1cSJaewon Kim /* 1633baceaf1cSJaewon Kim * Search for an unmapped address range. 1634baceaf1cSJaewon Kim * 1635baceaf1cSJaewon Kim * We are looking for a range that: 1636baceaf1cSJaewon Kim * - does not intersect with any VMA; 1637baceaf1cSJaewon Kim * - is contained within the [low_limit, high_limit) interval; 1638baceaf1cSJaewon Kim * - is at least the desired size. 1639baceaf1cSJaewon Kim * - satisfies (begin_addr & align_mask) == (align_offset & align_mask) 1640baceaf1cSJaewon Kim */ 1641baceaf1cSJaewon Kim unsigned long vm_unmapped_area(struct vm_unmapped_area_info *info) 1642baceaf1cSJaewon Kim { 1643df529cabSJaewon Kim unsigned long addr; 1644df529cabSJaewon Kim 1645baceaf1cSJaewon Kim if (info->flags & VM_UNMAPPED_AREA_TOPDOWN) 1646df529cabSJaewon Kim addr = unmapped_area_topdown(info); 1647baceaf1cSJaewon Kim else 1648df529cabSJaewon Kim addr = unmapped_area(info); 1649df529cabSJaewon Kim 1650df529cabSJaewon Kim trace_vm_unmapped_area(addr, info); 1651df529cabSJaewon Kim return addr; 1652baceaf1cSJaewon Kim } 1653f6795053SSteve Capper 16541da177e4SLinus Torvalds /* Get an address range which is currently unmapped. 16551da177e4SLinus Torvalds * For shmat() with addr=0. 16561da177e4SLinus Torvalds * 16571da177e4SLinus Torvalds * Ugly calling convention alert: 16581da177e4SLinus Torvalds * Return value with the low bits set means error value, 16591da177e4SLinus Torvalds * ie 16601da177e4SLinus Torvalds * if (ret & ~PAGE_MASK) 16611da177e4SLinus Torvalds * error = ret; 16621da177e4SLinus Torvalds * 16631da177e4SLinus Torvalds * This function "knows" that -ENOMEM has the bits set. 16641da177e4SLinus Torvalds */ 16651da177e4SLinus Torvalds unsigned long 16664b439e25SChristophe Leroy generic_get_unmapped_area(struct file *filp, unsigned long addr, 16674b439e25SChristophe Leroy unsigned long len, unsigned long pgoff, 16684b439e25SChristophe Leroy unsigned long flags) 16691da177e4SLinus Torvalds { 16701da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 16711be7107fSHugh Dickins struct vm_area_struct *vma, *prev; 1672db4fbfb9SMichel Lespinasse struct vm_unmapped_area_info info; 16732cb4de08SChristophe Leroy const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags); 16741da177e4SLinus Torvalds 1675f6795053SSteve Capper if (len > mmap_end - mmap_min_addr) 16761da177e4SLinus Torvalds return -ENOMEM; 16771da177e4SLinus Torvalds 167806abdfb4SBenjamin Herrenschmidt if (flags & MAP_FIXED) 167906abdfb4SBenjamin Herrenschmidt return addr; 168006abdfb4SBenjamin Herrenschmidt 16811da177e4SLinus Torvalds if (addr) { 16821da177e4SLinus Torvalds addr = PAGE_ALIGN(addr); 16831be7107fSHugh Dickins vma = find_vma_prev(mm, addr, &prev); 1684f6795053SSteve Capper if (mmap_end - len >= addr && addr >= mmap_min_addr && 16851be7107fSHugh Dickins (!vma || addr + len <= vm_start_gap(vma)) && 16861be7107fSHugh Dickins (!prev || addr >= vm_end_gap(prev))) 16871da177e4SLinus Torvalds return addr; 16881da177e4SLinus Torvalds } 16891da177e4SLinus Torvalds 1690db4fbfb9SMichel Lespinasse info.flags = 0; 1691db4fbfb9SMichel Lespinasse info.length = len; 16924e99b021SHeiko Carstens info.low_limit = mm->mmap_base; 1693f6795053SSteve Capper info.high_limit = mmap_end; 1694db4fbfb9SMichel Lespinasse info.align_mask = 0; 169509ef5283SJaewon Kim info.align_offset = 0; 1696db4fbfb9SMichel Lespinasse return vm_unmapped_area(&info); 16971da177e4SLinus Torvalds } 16984b439e25SChristophe Leroy 16994b439e25SChristophe Leroy #ifndef HAVE_ARCH_UNMAPPED_AREA 17004b439e25SChristophe Leroy unsigned long 17014b439e25SChristophe Leroy arch_get_unmapped_area(struct file *filp, unsigned long addr, 17024b439e25SChristophe Leroy unsigned long len, unsigned long pgoff, 17034b439e25SChristophe Leroy unsigned long flags) 17044b439e25SChristophe Leroy { 17054b439e25SChristophe Leroy return generic_get_unmapped_area(filp, addr, len, pgoff, flags); 17064b439e25SChristophe Leroy } 17071da177e4SLinus Torvalds #endif 17081da177e4SLinus Torvalds 17091da177e4SLinus Torvalds /* 17101da177e4SLinus Torvalds * This mmap-allocator allocates new areas top-down from below the 17111da177e4SLinus Torvalds * stack's low limit (the base): 17121da177e4SLinus Torvalds */ 17131da177e4SLinus Torvalds unsigned long 17144b439e25SChristophe Leroy generic_get_unmapped_area_topdown(struct file *filp, unsigned long addr, 171543cca0b1SYang Fan unsigned long len, unsigned long pgoff, 171643cca0b1SYang Fan unsigned long flags) 17171da177e4SLinus Torvalds { 17181be7107fSHugh Dickins struct vm_area_struct *vma, *prev; 17191da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 1720db4fbfb9SMichel Lespinasse struct vm_unmapped_area_info info; 17212cb4de08SChristophe Leroy const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags); 17221da177e4SLinus Torvalds 17231da177e4SLinus Torvalds /* requested length too big for entire address space */ 1724f6795053SSteve Capper if (len > mmap_end - mmap_min_addr) 17251da177e4SLinus Torvalds return -ENOMEM; 17261da177e4SLinus Torvalds 172706abdfb4SBenjamin Herrenschmidt if (flags & MAP_FIXED) 172806abdfb4SBenjamin Herrenschmidt return addr; 172906abdfb4SBenjamin Herrenschmidt 17301da177e4SLinus Torvalds /* requesting a specific address */ 17311da177e4SLinus Torvalds if (addr) { 17321da177e4SLinus Torvalds addr = PAGE_ALIGN(addr); 17331be7107fSHugh Dickins vma = find_vma_prev(mm, addr, &prev); 1734f6795053SSteve Capper if (mmap_end - len >= addr && addr >= mmap_min_addr && 17351be7107fSHugh Dickins (!vma || addr + len <= vm_start_gap(vma)) && 17361be7107fSHugh Dickins (!prev || addr >= vm_end_gap(prev))) 17371da177e4SLinus Torvalds return addr; 17381da177e4SLinus Torvalds } 17391da177e4SLinus Torvalds 1740db4fbfb9SMichel Lespinasse info.flags = VM_UNMAPPED_AREA_TOPDOWN; 1741db4fbfb9SMichel Lespinasse info.length = len; 17422afc745fSAkira Takeuchi info.low_limit = max(PAGE_SIZE, mmap_min_addr); 1743f6795053SSteve Capper info.high_limit = arch_get_mmap_base(addr, mm->mmap_base); 1744db4fbfb9SMichel Lespinasse info.align_mask = 0; 174509ef5283SJaewon Kim info.align_offset = 0; 1746db4fbfb9SMichel Lespinasse addr = vm_unmapped_area(&info); 1747b716ad95SXiao Guangrong 17481da177e4SLinus Torvalds /* 17491da177e4SLinus Torvalds * A failed mmap() very likely causes application failure, 17501da177e4SLinus Torvalds * so fall back to the bottom-up function here. This scenario 17511da177e4SLinus Torvalds * can happen with large stack limits and large mmap() 17521da177e4SLinus Torvalds * allocations. 17531da177e4SLinus Torvalds */ 1754de1741a1SAlexander Kuleshov if (offset_in_page(addr)) { 1755db4fbfb9SMichel Lespinasse VM_BUG_ON(addr != -ENOMEM); 1756db4fbfb9SMichel Lespinasse info.flags = 0; 1757db4fbfb9SMichel Lespinasse info.low_limit = TASK_UNMAPPED_BASE; 1758f6795053SSteve Capper info.high_limit = mmap_end; 1759db4fbfb9SMichel Lespinasse addr = vm_unmapped_area(&info); 1760db4fbfb9SMichel Lespinasse } 17611da177e4SLinus Torvalds 17621da177e4SLinus Torvalds return addr; 17631da177e4SLinus Torvalds } 17644b439e25SChristophe Leroy 17654b439e25SChristophe Leroy #ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN 17664b439e25SChristophe Leroy unsigned long 17674b439e25SChristophe Leroy arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr, 17684b439e25SChristophe Leroy unsigned long len, unsigned long pgoff, 17694b439e25SChristophe Leroy unsigned long flags) 17704b439e25SChristophe Leroy { 17714b439e25SChristophe Leroy return generic_get_unmapped_area_topdown(filp, addr, len, pgoff, flags); 17724b439e25SChristophe Leroy } 17731da177e4SLinus Torvalds #endif 17741da177e4SLinus Torvalds 17751da177e4SLinus Torvalds unsigned long 17761da177e4SLinus Torvalds get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, 17771da177e4SLinus Torvalds unsigned long pgoff, unsigned long flags) 17781da177e4SLinus Torvalds { 177906abdfb4SBenjamin Herrenschmidt unsigned long (*get_area)(struct file *, unsigned long, 178006abdfb4SBenjamin Herrenschmidt unsigned long, unsigned long, unsigned long); 178107ab67c8SLinus Torvalds 17829206de95SAl Viro unsigned long error = arch_mmap_check(addr, len, flags); 17839206de95SAl Viro if (error) 17849206de95SAl Viro return error; 17859206de95SAl Viro 17869206de95SAl Viro /* Careful about overflows.. */ 17879206de95SAl Viro if (len > TASK_SIZE) 17889206de95SAl Viro return -ENOMEM; 17899206de95SAl Viro 179007ab67c8SLinus Torvalds get_area = current->mm->get_unmapped_area; 1791c01d5b30SHugh Dickins if (file) { 1792c01d5b30SHugh Dickins if (file->f_op->get_unmapped_area) 179307ab67c8SLinus Torvalds get_area = file->f_op->get_unmapped_area; 1794c01d5b30SHugh Dickins } else if (flags & MAP_SHARED) { 1795c01d5b30SHugh Dickins /* 1796c01d5b30SHugh Dickins * mmap_region() will call shmem_zero_setup() to create a file, 1797c01d5b30SHugh Dickins * so use shmem's get_unmapped_area in case it can be huge. 179845e55300SPeter Collingbourne * do_mmap() will clear pgoff, so match alignment. 1799c01d5b30SHugh Dickins */ 1800c01d5b30SHugh Dickins pgoff = 0; 1801c01d5b30SHugh Dickins get_area = shmem_get_unmapped_area; 1802c01d5b30SHugh Dickins } 1803c01d5b30SHugh Dickins 180407ab67c8SLinus Torvalds addr = get_area(file, addr, len, pgoff, flags); 180507ab67c8SLinus Torvalds if (IS_ERR_VALUE(addr)) 180607ab67c8SLinus Torvalds return addr; 180707ab67c8SLinus Torvalds 18081da177e4SLinus Torvalds if (addr > TASK_SIZE - len) 18091da177e4SLinus Torvalds return -ENOMEM; 1810de1741a1SAlexander Kuleshov if (offset_in_page(addr)) 18111da177e4SLinus Torvalds return -EINVAL; 181206abdfb4SBenjamin Herrenschmidt 18139ac4ed4bSAl Viro error = security_mmap_addr(addr); 18149ac4ed4bSAl Viro return error ? error : addr; 18151da177e4SLinus Torvalds } 18161da177e4SLinus Torvalds 18171da177e4SLinus Torvalds EXPORT_SYMBOL(get_unmapped_area); 18181da177e4SLinus Torvalds 1819be8432e7SLiam R. Howlett /** 1820abdba2ddSLiam R. Howlett * find_vma_intersection() - Look up the first VMA which intersects the interval 1821abdba2ddSLiam R. Howlett * @mm: The process address space. 1822abdba2ddSLiam R. Howlett * @start_addr: The inclusive start user address. 1823abdba2ddSLiam R. Howlett * @end_addr: The exclusive end user address. 1824abdba2ddSLiam R. Howlett * 1825abdba2ddSLiam R. Howlett * Returns: The first VMA within the provided range, %NULL otherwise. Assumes 1826abdba2ddSLiam R. Howlett * start_addr < end_addr. 1827abdba2ddSLiam R. Howlett */ 1828abdba2ddSLiam R. Howlett struct vm_area_struct *find_vma_intersection(struct mm_struct *mm, 1829abdba2ddSLiam R. Howlett unsigned long start_addr, 1830abdba2ddSLiam R. Howlett unsigned long end_addr) 1831abdba2ddSLiam R. Howlett { 1832abdba2ddSLiam R. Howlett unsigned long index = start_addr; 1833abdba2ddSLiam R. Howlett 1834abdba2ddSLiam R. Howlett mmap_assert_locked(mm); 18357964cf8cSLiam R. Howlett return mt_find(&mm->mm_mt, &index, end_addr - 1); 1836abdba2ddSLiam R. Howlett } 1837abdba2ddSLiam R. Howlett EXPORT_SYMBOL(find_vma_intersection); 1838abdba2ddSLiam R. Howlett 1839abdba2ddSLiam R. Howlett /** 1840be8432e7SLiam R. Howlett * find_vma() - Find the VMA for a given address, or the next VMA. 1841be8432e7SLiam R. Howlett * @mm: The mm_struct to check 1842be8432e7SLiam R. Howlett * @addr: The address 1843be8432e7SLiam R. Howlett * 1844be8432e7SLiam R. Howlett * Returns: The VMA associated with addr, or the next VMA. 1845be8432e7SLiam R. Howlett * May return %NULL in the case of no VMA at addr or above. 1846be8432e7SLiam R. Howlett */ 18471da177e4SLinus Torvalds struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) 18481da177e4SLinus Torvalds { 1849be8432e7SLiam R. Howlett unsigned long index = addr; 18501da177e4SLinus Torvalds 18515b78ed24SLuigi Rizzo mmap_assert_locked(mm); 18527964cf8cSLiam R. Howlett return mt_find(&mm->mm_mt, &index, ULONG_MAX); 18531da177e4SLinus Torvalds } 18541da177e4SLinus Torvalds EXPORT_SYMBOL(find_vma); 18551da177e4SLinus Torvalds 18567fdbd37dSLiam R. Howlett /** 18577fdbd37dSLiam R. Howlett * find_vma_prev() - Find the VMA for a given address, or the next vma and 18587fdbd37dSLiam R. Howlett * set %pprev to the previous VMA, if any. 18597fdbd37dSLiam R. Howlett * @mm: The mm_struct to check 18607fdbd37dSLiam R. Howlett * @addr: The address 18617fdbd37dSLiam R. Howlett * @pprev: The pointer to set to the previous VMA 18627fdbd37dSLiam R. Howlett * 18637fdbd37dSLiam R. Howlett * Note that RCU lock is missing here since the external mmap_lock() is used 18647fdbd37dSLiam R. Howlett * instead. 18657fdbd37dSLiam R. Howlett * 18667fdbd37dSLiam R. Howlett * Returns: The VMA associated with @addr, or the next vma. 18677fdbd37dSLiam R. Howlett * May return %NULL in the case of no vma at addr or above. 18686bd4837dSKOSAKI Motohiro */ 18691da177e4SLinus Torvalds struct vm_area_struct * 18701da177e4SLinus Torvalds find_vma_prev(struct mm_struct *mm, unsigned long addr, 18711da177e4SLinus Torvalds struct vm_area_struct **pprev) 18721da177e4SLinus Torvalds { 18736bd4837dSKOSAKI Motohiro struct vm_area_struct *vma; 18747fdbd37dSLiam R. Howlett MA_STATE(mas, &mm->mm_mt, addr, addr); 18751da177e4SLinus Torvalds 18767fdbd37dSLiam R. Howlett vma = mas_walk(&mas); 18777fdbd37dSLiam R. Howlett *pprev = mas_prev(&mas, 0); 18787fdbd37dSLiam R. Howlett if (!vma) 18797fdbd37dSLiam R. Howlett vma = mas_next(&mas, ULONG_MAX); 18806bd4837dSKOSAKI Motohiro return vma; 18811da177e4SLinus Torvalds } 18821da177e4SLinus Torvalds 18831da177e4SLinus Torvalds /* 18841da177e4SLinus Torvalds * Verify that the stack growth is acceptable and 18851da177e4SLinus Torvalds * update accounting. This is shared with both the 18861da177e4SLinus Torvalds * grow-up and grow-down cases. 18871da177e4SLinus Torvalds */ 18881be7107fSHugh Dickins static int acct_stack_growth(struct vm_area_struct *vma, 18891be7107fSHugh Dickins unsigned long size, unsigned long grow) 18901da177e4SLinus Torvalds { 18911da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 18921be7107fSHugh Dickins unsigned long new_start; 18931da177e4SLinus Torvalds 18941da177e4SLinus Torvalds /* address space limit tests */ 189584638335SKonstantin Khlebnikov if (!may_expand_vm(mm, vma->vm_flags, grow)) 18961da177e4SLinus Torvalds return -ENOMEM; 18971da177e4SLinus Torvalds 18981da177e4SLinus Torvalds /* Stack limit test */ 189924c79d8eSKrzysztof Opasiak if (size > rlimit(RLIMIT_STACK)) 19001da177e4SLinus Torvalds return -ENOMEM; 19011da177e4SLinus Torvalds 19021da177e4SLinus Torvalds /* mlock limit tests */ 1903c5d8a364SMiaohe Lin if (mlock_future_check(mm, vma->vm_flags, grow << PAGE_SHIFT)) 19041da177e4SLinus Torvalds return -ENOMEM; 19051da177e4SLinus Torvalds 19060d59a01bSAdam Litke /* Check to ensure the stack will not grow into a hugetlb-only region */ 19070d59a01bSAdam Litke new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start : 19080d59a01bSAdam Litke vma->vm_end - size; 19090d59a01bSAdam Litke if (is_hugepage_only_range(vma->vm_mm, new_start, size)) 19100d59a01bSAdam Litke return -EFAULT; 19110d59a01bSAdam Litke 19121da177e4SLinus Torvalds /* 19131da177e4SLinus Torvalds * Overcommit.. This must be the final test, as it will 19141da177e4SLinus Torvalds * update security statistics. 19151da177e4SLinus Torvalds */ 191605fa199dSHugh Dickins if (security_vm_enough_memory_mm(mm, grow)) 19171da177e4SLinus Torvalds return -ENOMEM; 19181da177e4SLinus Torvalds 19191da177e4SLinus Torvalds return 0; 19201da177e4SLinus Torvalds } 19211da177e4SLinus Torvalds 192246dea3d0SHugh Dickins #if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64) 19231da177e4SLinus Torvalds /* 192446dea3d0SHugh Dickins * PA-RISC uses this for its stack; IA64 for its Register Backing Store. 192546dea3d0SHugh Dickins * vma is the last one with address > vma->vm_end. Have to extend vma. 19261da177e4SLinus Torvalds */ 192746dea3d0SHugh Dickins int expand_upwards(struct vm_area_struct *vma, unsigned long address) 19281da177e4SLinus Torvalds { 192909357814SOleg Nesterov struct mm_struct *mm = vma->vm_mm; 19301be7107fSHugh Dickins struct vm_area_struct *next; 19311be7107fSHugh Dickins unsigned long gap_addr; 193212352d3cSKonstantin Khlebnikov int error = 0; 1933d4af56c5SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 19341da177e4SLinus Torvalds 19351da177e4SLinus Torvalds if (!(vma->vm_flags & VM_GROWSUP)) 19361da177e4SLinus Torvalds return -EFAULT; 19371da177e4SLinus Torvalds 1938bd726c90SHelge Deller /* Guard against exceeding limits of the address space. */ 19391be7107fSHugh Dickins address &= PAGE_MASK; 194037511fb5SHelge Deller if (address >= (TASK_SIZE & PAGE_MASK)) 194112352d3cSKonstantin Khlebnikov return -ENOMEM; 1942bd726c90SHelge Deller address += PAGE_SIZE; 194312352d3cSKonstantin Khlebnikov 19441be7107fSHugh Dickins /* Enforce stack_guard_gap */ 19451be7107fSHugh Dickins gap_addr = address + stack_guard_gap; 1946bd726c90SHelge Deller 1947bd726c90SHelge Deller /* Guard against overflow */ 1948bd726c90SHelge Deller if (gap_addr < address || gap_addr > TASK_SIZE) 1949bd726c90SHelge Deller gap_addr = TASK_SIZE; 1950bd726c90SHelge Deller 1951763ecb03SLiam R. Howlett next = find_vma_intersection(mm, vma->vm_end, gap_addr); 1952763ecb03SLiam R. Howlett if (next && vma_is_accessible(next)) { 19531be7107fSHugh Dickins if (!(next->vm_flags & VM_GROWSUP)) 19541be7107fSHugh Dickins return -ENOMEM; 19551be7107fSHugh Dickins /* Check that both stack segments have the same anon_vma? */ 19561be7107fSHugh Dickins } 19571be7107fSHugh Dickins 1958c5d5546eSVernon Yang if (mas_preallocate(&mas, GFP_KERNEL)) 19591da177e4SLinus Torvalds return -ENOMEM; 19601da177e4SLinus Torvalds 1961d4af56c5SLiam R. Howlett /* We must make sure the anon_vma is allocated. */ 1962d4af56c5SLiam R. Howlett if (unlikely(anon_vma_prepare(vma))) { 1963d4af56c5SLiam R. Howlett mas_destroy(&mas); 1964d4af56c5SLiam R. Howlett return -ENOMEM; 1965d4af56c5SLiam R. Howlett } 1966d4af56c5SLiam R. Howlett 19671da177e4SLinus Torvalds /* 19681da177e4SLinus Torvalds * vma->vm_start/vm_end cannot change under us because the caller 1969c1e8d7c6SMichel Lespinasse * is required to hold the mmap_lock in read mode. We need the 19701da177e4SLinus Torvalds * anon_vma lock to serialize against concurrent expand_stacks. 19711da177e4SLinus Torvalds */ 197212352d3cSKonstantin Khlebnikov anon_vma_lock_write(vma->anon_vma); 19731da177e4SLinus Torvalds 19741da177e4SLinus Torvalds /* Somebody else might have raced and expanded it already */ 19751da177e4SLinus Torvalds if (address > vma->vm_end) { 19761da177e4SLinus Torvalds unsigned long size, grow; 19771da177e4SLinus Torvalds 19781da177e4SLinus Torvalds size = address - vma->vm_start; 19791da177e4SLinus Torvalds grow = (address - vma->vm_end) >> PAGE_SHIFT; 19801da177e4SLinus Torvalds 198142c36f63SHugh Dickins error = -ENOMEM; 198242c36f63SHugh Dickins if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) { 19831da177e4SLinus Torvalds error = acct_stack_growth(vma, size, grow); 19843af9e859SEric B Munson if (!error) { 19854128997bSMichel Lespinasse /* 1986524e00b3SLiam R. Howlett * We only hold a shared mmap_lock lock here, so 1987524e00b3SLiam R. Howlett * we need to protect against concurrent vma 1988524e00b3SLiam R. Howlett * expansions. anon_vma_lock_write() doesn't 1989524e00b3SLiam R. Howlett * help here, as we don't guarantee that all 1990524e00b3SLiam R. Howlett * growable vmas in a mm share the same root 1991524e00b3SLiam R. Howlett * anon vma. So, we reuse mm->page_table_lock 1992524e00b3SLiam R. Howlett * to guard against concurrent vma expansions. 19934128997bSMichel Lespinasse */ 199409357814SOleg Nesterov spin_lock(&mm->page_table_lock); 199587e8827bSOleg Nesterov if (vma->vm_flags & VM_LOCKED) 199609357814SOleg Nesterov mm->locked_vm += grow; 199784638335SKonstantin Khlebnikov vm_stat_account(mm, vma->vm_flags, grow); 1998bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(vma); 19991da177e4SLinus Torvalds vma->vm_end = address; 2000d4af56c5SLiam R. Howlett /* Overwrite old entry in mtree. */ 2001d4af56c5SLiam R. Howlett vma_mas_store(vma, &mas); 2002bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(vma); 200309357814SOleg Nesterov spin_unlock(&mm->page_table_lock); 20044128997bSMichel Lespinasse 20053af9e859SEric B Munson perf_event_mmap(vma); 20063af9e859SEric B Munson } 20071da177e4SLinus Torvalds } 200842c36f63SHugh Dickins } 200912352d3cSKonstantin Khlebnikov anon_vma_unlock_write(vma->anon_vma); 2010c791576cSYang Shi khugepaged_enter_vma(vma, vma->vm_flags); 2011d4af56c5SLiam R. Howlett mas_destroy(&mas); 20121da177e4SLinus Torvalds return error; 20131da177e4SLinus Torvalds } 201446dea3d0SHugh Dickins #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */ 201546dea3d0SHugh Dickins 20161da177e4SLinus Torvalds /* 20171da177e4SLinus Torvalds * vma is the first one with address < vma->vm_start. Have to extend vma. 20181da177e4SLinus Torvalds */ 2019524e00b3SLiam R. Howlett int expand_downwards(struct vm_area_struct *vma, unsigned long address) 20201da177e4SLinus Torvalds { 202109357814SOleg Nesterov struct mm_struct *mm = vma->vm_mm; 2022763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, vma->vm_start, vma->vm_start); 20231be7107fSHugh Dickins struct vm_area_struct *prev; 20240a1d5299SJann Horn int error = 0; 20251da177e4SLinus Torvalds 20268869477aSEric Paris address &= PAGE_MASK; 20270a1d5299SJann Horn if (address < mmap_min_addr) 20280a1d5299SJann Horn return -EPERM; 20298869477aSEric Paris 20301be7107fSHugh Dickins /* Enforce stack_guard_gap */ 2031763ecb03SLiam R. Howlett prev = mas_prev(&mas, 0); 20321be7107fSHugh Dickins /* Check that both stack segments have the same anon_vma? */ 203332e4e6d5SOleg Nesterov if (prev && !(prev->vm_flags & VM_GROWSDOWN) && 20343122e80eSAnshuman Khandual vma_is_accessible(prev)) { 203532e4e6d5SOleg Nesterov if (address - prev->vm_end < stack_guard_gap) 203632e4e6d5SOleg Nesterov return -ENOMEM; 20371be7107fSHugh Dickins } 20381be7107fSHugh Dickins 2039c5d5546eSVernon Yang if (mas_preallocate(&mas, GFP_KERNEL)) 204012352d3cSKonstantin Khlebnikov return -ENOMEM; 20411da177e4SLinus Torvalds 2042d4af56c5SLiam R. Howlett /* We must make sure the anon_vma is allocated. */ 2043d4af56c5SLiam R. Howlett if (unlikely(anon_vma_prepare(vma))) { 2044d4af56c5SLiam R. Howlett mas_destroy(&mas); 2045d4af56c5SLiam R. Howlett return -ENOMEM; 2046d4af56c5SLiam R. Howlett } 2047d4af56c5SLiam R. Howlett 20481da177e4SLinus Torvalds /* 20491da177e4SLinus Torvalds * vma->vm_start/vm_end cannot change under us because the caller 2050c1e8d7c6SMichel Lespinasse * is required to hold the mmap_lock in read mode. We need the 20511da177e4SLinus Torvalds * anon_vma lock to serialize against concurrent expand_stacks. 20521da177e4SLinus Torvalds */ 205312352d3cSKonstantin Khlebnikov anon_vma_lock_write(vma->anon_vma); 20541da177e4SLinus Torvalds 20551da177e4SLinus Torvalds /* Somebody else might have raced and expanded it already */ 20561da177e4SLinus Torvalds if (address < vma->vm_start) { 20571da177e4SLinus Torvalds unsigned long size, grow; 20581da177e4SLinus Torvalds 20591da177e4SLinus Torvalds size = vma->vm_end - address; 20601da177e4SLinus Torvalds grow = (vma->vm_start - address) >> PAGE_SHIFT; 20611da177e4SLinus Torvalds 2062a626ca6aSLinus Torvalds error = -ENOMEM; 2063a626ca6aSLinus Torvalds if (grow <= vma->vm_pgoff) { 20641da177e4SLinus Torvalds error = acct_stack_growth(vma, size, grow); 20651da177e4SLinus Torvalds if (!error) { 20664128997bSMichel Lespinasse /* 2067524e00b3SLiam R. Howlett * We only hold a shared mmap_lock lock here, so 2068524e00b3SLiam R. Howlett * we need to protect against concurrent vma 2069524e00b3SLiam R. Howlett * expansions. anon_vma_lock_write() doesn't 2070524e00b3SLiam R. Howlett * help here, as we don't guarantee that all 2071524e00b3SLiam R. Howlett * growable vmas in a mm share the same root 2072524e00b3SLiam R. Howlett * anon vma. So, we reuse mm->page_table_lock 2073524e00b3SLiam R. Howlett * to guard against concurrent vma expansions. 20744128997bSMichel Lespinasse */ 207509357814SOleg Nesterov spin_lock(&mm->page_table_lock); 207687e8827bSOleg Nesterov if (vma->vm_flags & VM_LOCKED) 207709357814SOleg Nesterov mm->locked_vm += grow; 207884638335SKonstantin Khlebnikov vm_stat_account(mm, vma->vm_flags, grow); 2079bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(vma); 20801da177e4SLinus Torvalds vma->vm_start = address; 20811da177e4SLinus Torvalds vma->vm_pgoff -= grow; 2082d4af56c5SLiam R. Howlett /* Overwrite old entry in mtree. */ 2083d4af56c5SLiam R. Howlett vma_mas_store(vma, &mas); 2084bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(vma); 208509357814SOleg Nesterov spin_unlock(&mm->page_table_lock); 20864128997bSMichel Lespinasse 20873af9e859SEric B Munson perf_event_mmap(vma); 20881da177e4SLinus Torvalds } 20891da177e4SLinus Torvalds } 2090a626ca6aSLinus Torvalds } 209112352d3cSKonstantin Khlebnikov anon_vma_unlock_write(vma->anon_vma); 2092c791576cSYang Shi khugepaged_enter_vma(vma, vma->vm_flags); 2093d4af56c5SLiam R. Howlett mas_destroy(&mas); 20941da177e4SLinus Torvalds return error; 20951da177e4SLinus Torvalds } 20961da177e4SLinus Torvalds 20971be7107fSHugh Dickins /* enforced gap between the expanding stack and other mappings. */ 20981be7107fSHugh Dickins unsigned long stack_guard_gap = 256UL<<PAGE_SHIFT; 20991be7107fSHugh Dickins 21001be7107fSHugh Dickins static int __init cmdline_parse_stack_guard_gap(char *p) 21011be7107fSHugh Dickins { 21021be7107fSHugh Dickins unsigned long val; 21031be7107fSHugh Dickins char *endptr; 21041be7107fSHugh Dickins 21051be7107fSHugh Dickins val = simple_strtoul(p, &endptr, 10); 21061be7107fSHugh Dickins if (!*endptr) 21071be7107fSHugh Dickins stack_guard_gap = val << PAGE_SHIFT; 21081be7107fSHugh Dickins 2109e6d09493SRandy Dunlap return 1; 21101be7107fSHugh Dickins } 21111be7107fSHugh Dickins __setup("stack_guard_gap=", cmdline_parse_stack_guard_gap); 21121be7107fSHugh Dickins 2113b6a2fea3SOllie Wild #ifdef CONFIG_STACK_GROWSUP 2114b6a2fea3SOllie Wild int expand_stack(struct vm_area_struct *vma, unsigned long address) 2115b6a2fea3SOllie Wild { 2116b6a2fea3SOllie Wild return expand_upwards(vma, address); 2117b6a2fea3SOllie Wild } 2118b6a2fea3SOllie Wild 2119b6a2fea3SOllie Wild struct vm_area_struct * 2120b6a2fea3SOllie Wild find_extend_vma(struct mm_struct *mm, unsigned long addr) 2121b6a2fea3SOllie Wild { 2122b6a2fea3SOllie Wild struct vm_area_struct *vma, *prev; 2123b6a2fea3SOllie Wild 2124b6a2fea3SOllie Wild addr &= PAGE_MASK; 2125b6a2fea3SOllie Wild vma = find_vma_prev(mm, addr, &prev); 2126b6a2fea3SOllie Wild if (vma && (vma->vm_start <= addr)) 2127b6a2fea3SOllie Wild return vma; 21284d45e75aSJann Horn if (!prev || expand_stack(prev, addr)) 2129b6a2fea3SOllie Wild return NULL; 2130cea10a19SMichel Lespinasse if (prev->vm_flags & VM_LOCKED) 2131fc05f566SKirill A. Shutemov populate_vma_page_range(prev, addr, prev->vm_end, NULL); 2132b6a2fea3SOllie Wild return prev; 2133b6a2fea3SOllie Wild } 2134b6a2fea3SOllie Wild #else 2135b6a2fea3SOllie Wild int expand_stack(struct vm_area_struct *vma, unsigned long address) 2136b6a2fea3SOllie Wild { 2137b6a2fea3SOllie Wild return expand_downwards(vma, address); 2138b6a2fea3SOllie Wild } 2139b6a2fea3SOllie Wild 21401da177e4SLinus Torvalds struct vm_area_struct * 21411da177e4SLinus Torvalds find_extend_vma(struct mm_struct *mm, unsigned long addr) 21421da177e4SLinus Torvalds { 21431da177e4SLinus Torvalds struct vm_area_struct *vma; 21441da177e4SLinus Torvalds unsigned long start; 21451da177e4SLinus Torvalds 21461da177e4SLinus Torvalds addr &= PAGE_MASK; 21471da177e4SLinus Torvalds vma = find_vma(mm, addr); 21481da177e4SLinus Torvalds if (!vma) 21491da177e4SLinus Torvalds return NULL; 21501da177e4SLinus Torvalds if (vma->vm_start <= addr) 21511da177e4SLinus Torvalds return vma; 21521da177e4SLinus Torvalds if (!(vma->vm_flags & VM_GROWSDOWN)) 21531da177e4SLinus Torvalds return NULL; 21541da177e4SLinus Torvalds start = vma->vm_start; 21551da177e4SLinus Torvalds if (expand_stack(vma, addr)) 21561da177e4SLinus Torvalds return NULL; 2157cea10a19SMichel Lespinasse if (vma->vm_flags & VM_LOCKED) 2158fc05f566SKirill A. Shutemov populate_vma_page_range(vma, addr, start, NULL); 21591da177e4SLinus Torvalds return vma; 21601da177e4SLinus Torvalds } 21611da177e4SLinus Torvalds #endif 21621da177e4SLinus Torvalds 2163e1d6d01aSJesse Barnes EXPORT_SYMBOL_GPL(find_extend_vma); 2164e1d6d01aSJesse Barnes 21652c0b3814SHugh Dickins /* 2166763ecb03SLiam R. Howlett * Ok - we have the memory areas we should free on a maple tree so release them, 2167763ecb03SLiam R. Howlett * and do the vma updates. 21681da177e4SLinus Torvalds * 21692c0b3814SHugh Dickins * Called with the mm semaphore held. 21701da177e4SLinus Torvalds */ 2171763ecb03SLiam R. Howlett static inline void remove_mt(struct mm_struct *mm, struct ma_state *mas) 21721da177e4SLinus Torvalds { 21734f74d2c8SLinus Torvalds unsigned long nr_accounted = 0; 2174763ecb03SLiam R. Howlett struct vm_area_struct *vma; 21754f74d2c8SLinus Torvalds 2176365e9c87SHugh Dickins /* Update high watermark before we lower total_vm */ 2177365e9c87SHugh Dickins update_hiwater_vm(mm); 2178763ecb03SLiam R. Howlett mas_for_each(mas, vma, ULONG_MAX) { 2179ab50b8edSHugh Dickins long nrpages = vma_pages(vma); 21801da177e4SLinus Torvalds 21814f74d2c8SLinus Torvalds if (vma->vm_flags & VM_ACCOUNT) 21824f74d2c8SLinus Torvalds nr_accounted += nrpages; 218384638335SKonstantin Khlebnikov vm_stat_account(mm, vma->vm_flags, -nrpages); 2184763ecb03SLiam R. Howlett remove_vma(vma); 2185763ecb03SLiam R. Howlett } 21864f74d2c8SLinus Torvalds vm_unacct_memory(nr_accounted); 21871da177e4SLinus Torvalds validate_mm(mm); 21881da177e4SLinus Torvalds } 21891da177e4SLinus Torvalds 21901da177e4SLinus Torvalds /* 21911da177e4SLinus Torvalds * Get rid of page table information in the indicated region. 21921da177e4SLinus Torvalds * 2193f10df686SPaolo 'Blaisorblade' Giarrusso * Called with the mm semaphore held. 21941da177e4SLinus Torvalds */ 2195763ecb03SLiam R. Howlett static void unmap_region(struct mm_struct *mm, struct maple_tree *mt, 2196e0da382cSHugh Dickins struct vm_area_struct *vma, struct vm_area_struct *prev, 2197763ecb03SLiam R. Howlett struct vm_area_struct *next, 2198e0da382cSHugh Dickins unsigned long start, unsigned long end) 21991da177e4SLinus Torvalds { 2200d16dfc55SPeter Zijlstra struct mmu_gather tlb; 22011da177e4SLinus Torvalds 22021da177e4SLinus Torvalds lru_add_drain(); 2203a72afd87SWill Deacon tlb_gather_mmu(&tlb, mm); 2204365e9c87SHugh Dickins update_hiwater_rss(mm); 2205763ecb03SLiam R. Howlett unmap_vmas(&tlb, mt, vma, start, end); 2206763ecb03SLiam R. Howlett free_pgtables(&tlb, mt, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS, 22076ee8630eSHugh Dickins next ? next->vm_start : USER_PGTABLES_CEILING); 2208ae8eba8bSWill Deacon tlb_finish_mmu(&tlb); 22091da177e4SLinus Torvalds } 22101da177e4SLinus Torvalds 22111da177e4SLinus Torvalds /* 2212def5efe0SDavid Rientjes * __split_vma() bypasses sysctl_max_map_count checking. We use this where it 2213def5efe0SDavid Rientjes * has already been checked or doesn't make sense to fail. 22141da177e4SLinus Torvalds */ 2215def5efe0SDavid Rientjes int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma, 22161da177e4SLinus Torvalds unsigned long addr, int new_below) 22171da177e4SLinus Torvalds { 22181da177e4SLinus Torvalds struct vm_area_struct *new; 2219e3975891SChen Gang int err; 2220d4af56c5SLiam R. Howlett validate_mm_mt(mm); 22211da177e4SLinus Torvalds 2222dd3b614fSDmitry Safonov if (vma->vm_ops && vma->vm_ops->may_split) { 2223dd3b614fSDmitry Safonov err = vma->vm_ops->may_split(vma, addr); 222431383c68SDan Williams if (err) 222531383c68SDan Williams return err; 222631383c68SDan Williams } 22271da177e4SLinus Torvalds 22283928d4f5SLinus Torvalds new = vm_area_dup(vma); 22291da177e4SLinus Torvalds if (!new) 2230e3975891SChen Gang return -ENOMEM; 22311da177e4SLinus Torvalds 22321da177e4SLinus Torvalds if (new_below) 22331da177e4SLinus Torvalds new->vm_end = addr; 22341da177e4SLinus Torvalds else { 22351da177e4SLinus Torvalds new->vm_start = addr; 22361da177e4SLinus Torvalds new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT); 22371da177e4SLinus Torvalds } 22381da177e4SLinus Torvalds 2239ef0855d3SOleg Nesterov err = vma_dup_policy(vma, new); 2240ef0855d3SOleg Nesterov if (err) 22415beb4930SRik van Riel goto out_free_vma; 22421da177e4SLinus Torvalds 2243c4ea95d7SDaniel Forrest err = anon_vma_clone(new, vma); 2244c4ea95d7SDaniel Forrest if (err) 22455beb4930SRik van Riel goto out_free_mpol; 22465beb4930SRik van Riel 2247e9714acfSKonstantin Khlebnikov if (new->vm_file) 22481da177e4SLinus Torvalds get_file(new->vm_file); 22491da177e4SLinus Torvalds 22501da177e4SLinus Torvalds if (new->vm_ops && new->vm_ops->open) 22511da177e4SLinus Torvalds new->vm_ops->open(new); 22521da177e4SLinus Torvalds 22531da177e4SLinus Torvalds if (new_below) 22545beb4930SRik van Riel err = vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff + 22551da177e4SLinus Torvalds ((addr - new->vm_start) >> PAGE_SHIFT), new); 22561da177e4SLinus Torvalds else 22575beb4930SRik van Riel err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new); 22581da177e4SLinus Torvalds 22595beb4930SRik van Riel /* Success. */ 22605beb4930SRik van Riel if (!err) 22611da177e4SLinus Torvalds return 0; 22625beb4930SRik van Riel 2263d4af56c5SLiam R. Howlett /* Avoid vm accounting in close() operation */ 2264d4af56c5SLiam R. Howlett new->vm_start = new->vm_end; 2265d4af56c5SLiam R. Howlett new->vm_pgoff = 0; 22665beb4930SRik van Riel /* Clean everything up if vma_adjust failed. */ 226758927533SRik van Riel if (new->vm_ops && new->vm_ops->close) 22685beb4930SRik van Riel new->vm_ops->close(new); 2269e9714acfSKonstantin Khlebnikov if (new->vm_file) 22705beb4930SRik van Riel fput(new->vm_file); 22712aeadc30SAndrea Arcangeli unlink_anon_vmas(new); 22725beb4930SRik van Riel out_free_mpol: 2273ef0855d3SOleg Nesterov mpol_put(vma_policy(new)); 22745beb4930SRik van Riel out_free_vma: 22753928d4f5SLinus Torvalds vm_area_free(new); 2276d4af56c5SLiam R. Howlett validate_mm_mt(mm); 22775beb4930SRik van Riel return err; 22781da177e4SLinus Torvalds } 22791da177e4SLinus Torvalds 2280659ace58SKOSAKI Motohiro /* 2281659ace58SKOSAKI Motohiro * Split a vma into two pieces at address 'addr', a new vma is allocated 2282659ace58SKOSAKI Motohiro * either for the first part or the tail. 2283659ace58SKOSAKI Motohiro */ 2284659ace58SKOSAKI Motohiro int split_vma(struct mm_struct *mm, struct vm_area_struct *vma, 2285659ace58SKOSAKI Motohiro unsigned long addr, int new_below) 2286659ace58SKOSAKI Motohiro { 2287659ace58SKOSAKI Motohiro if (mm->map_count >= sysctl_max_map_count) 2288659ace58SKOSAKI Motohiro return -ENOMEM; 2289659ace58SKOSAKI Motohiro 2290659ace58SKOSAKI Motohiro return __split_vma(mm, vma, addr, new_below); 2291659ace58SKOSAKI Motohiro } 2292659ace58SKOSAKI Motohiro 2293763ecb03SLiam R. Howlett static inline int munmap_sidetree(struct vm_area_struct *vma, 2294763ecb03SLiam R. Howlett struct ma_state *mas_detach) 22951da177e4SLinus Torvalds { 2296763ecb03SLiam R. Howlett mas_set_range(mas_detach, vma->vm_start, vma->vm_end - 1); 2297763ecb03SLiam R. Howlett if (mas_store_gfp(mas_detach, vma, GFP_KERNEL)) 2298763ecb03SLiam R. Howlett return -ENOMEM; 229911f9a21aSLiam R. Howlett 2300763ecb03SLiam R. Howlett if (vma->vm_flags & VM_LOCKED) 2301763ecb03SLiam R. Howlett vma->vm_mm->locked_vm -= vma_pages(vma); 230211f9a21aSLiam R. Howlett 2303763ecb03SLiam R. Howlett return 0; 230411f9a21aSLiam R. Howlett } 230511f9a21aSLiam R. Howlett 230611f9a21aSLiam R. Howlett /* 2307183654ceSLiam R. Howlett * do_vmi_align_munmap() - munmap the aligned region from @start to @end. 2308183654ceSLiam R. Howlett * @vmi: The vma iterator 230911f9a21aSLiam R. Howlett * @vma: The starting vm_area_struct 231011f9a21aSLiam R. Howlett * @mm: The mm_struct 231111f9a21aSLiam R. Howlett * @start: The aligned start address to munmap. 231211f9a21aSLiam R. Howlett * @end: The aligned end address to munmap. 231311f9a21aSLiam R. Howlett * @uf: The userfaultfd list_head 23148651a137SLorenzo Stoakes * @downgrade: Set to true to attempt a write downgrade of the mmap_lock 231511f9a21aSLiam R. Howlett * 231611f9a21aSLiam R. Howlett * If @downgrade is true, check return code for potential release of the lock. 231711f9a21aSLiam R. Howlett */ 231811f9a21aSLiam R. Howlett static int 2319183654ceSLiam R. Howlett do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma, 232011f9a21aSLiam R. Howlett struct mm_struct *mm, unsigned long start, 232111f9a21aSLiam R. Howlett unsigned long end, struct list_head *uf, bool downgrade) 232211f9a21aSLiam R. Howlett { 2323763ecb03SLiam R. Howlett struct vm_area_struct *prev, *next = NULL; 2324763ecb03SLiam R. Howlett struct maple_tree mt_detach; 2325763ecb03SLiam R. Howlett int count = 0; 2326d4af56c5SLiam R. Howlett int error = -ENOMEM; 2327763ecb03SLiam R. Howlett MA_STATE(mas_detach, &mt_detach, 0, 0); 2328763ecb03SLiam R. Howlett mt_init_flags(&mt_detach, MT_FLAGS_LOCK_EXTERN); 2329763ecb03SLiam R. Howlett mt_set_external_lock(&mt_detach, &mm->mmap_lock); 2330524e00b3SLiam R. Howlett 23311da177e4SLinus Torvalds /* 23321da177e4SLinus Torvalds * If we need to split any vma, do it now to save pain later. 23331da177e4SLinus Torvalds * 23341da177e4SLinus Torvalds * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially 23351da177e4SLinus Torvalds * unmapped vm_area_struct will remain in use: so lower split_vma 23361da177e4SLinus Torvalds * places tmp vma above, and higher split_vma places tmp vma below. 23371da177e4SLinus Torvalds */ 2338763ecb03SLiam R. Howlett 2339763ecb03SLiam R. Howlett /* Does it split the first one? */ 2340146425a3SHugh Dickins if (start > vma->vm_start) { 2341659ace58SKOSAKI Motohiro 2342659ace58SKOSAKI Motohiro /* 2343659ace58SKOSAKI Motohiro * Make sure that map_count on return from munmap() will 2344659ace58SKOSAKI Motohiro * not exceed its limit; but let map_count go just above 2345659ace58SKOSAKI Motohiro * its limit temporarily, to help free resources as expected. 2346659ace58SKOSAKI Motohiro */ 2347659ace58SKOSAKI Motohiro if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count) 2348d4af56c5SLiam R. Howlett goto map_count_exceeded; 2349659ace58SKOSAKI Motohiro 2350659ace58SKOSAKI Motohiro error = __split_vma(mm, vma, start, 0); 23511da177e4SLinus Torvalds if (error) 2352763ecb03SLiam R. Howlett goto start_split_failed; 235311f9a21aSLiam R. Howlett 2354183654ceSLiam R. Howlett vma_iter_set(vmi, start); 2355183654ceSLiam R. Howlett vma = vma_find(vmi, end); 23561da177e4SLinus Torvalds } 23571da177e4SLinus Torvalds 2358183654ceSLiam R. Howlett prev = vma_prev(vmi); 2359763ecb03SLiam R. Howlett if (unlikely((!prev))) 2360183654ceSLiam R. Howlett vma_iter_set(vmi, start); 236111f9a21aSLiam R. Howlett 2362763ecb03SLiam R. Howlett /* 2363763ecb03SLiam R. Howlett * Detach a range of VMAs from the mm. Using next as a temp variable as 2364763ecb03SLiam R. Howlett * it is always overwritten. 2365763ecb03SLiam R. Howlett */ 2366183654ceSLiam R. Howlett for_each_vma_range(*vmi, next, end) { 2367763ecb03SLiam R. Howlett /* Does it split the end? */ 2368763ecb03SLiam R. Howlett if (next->vm_end > end) { 2369763ecb03SLiam R. Howlett struct vm_area_struct *split; 237011f9a21aSLiam R. Howlett 2371763ecb03SLiam R. Howlett error = __split_vma(mm, next, end, 1); 23721da177e4SLinus Torvalds if (error) 2373763ecb03SLiam R. Howlett goto end_split_failed; 237411f9a21aSLiam R. Howlett 2375183654ceSLiam R. Howlett vma_iter_set(vmi, end); 2376183654ceSLiam R. Howlett split = vma_prev(vmi); 2377763ecb03SLiam R. Howlett error = munmap_sidetree(split, &mas_detach); 2378763ecb03SLiam R. Howlett if (error) 2379763ecb03SLiam R. Howlett goto munmap_sidetree_failed; 2380763ecb03SLiam R. Howlett 2381763ecb03SLiam R. Howlett count++; 2382763ecb03SLiam R. Howlett if (vma == next) 2383763ecb03SLiam R. Howlett vma = split; 2384763ecb03SLiam R. Howlett break; 238511f9a21aSLiam R. Howlett } 2386763ecb03SLiam R. Howlett error = munmap_sidetree(next, &mas_detach); 2387763ecb03SLiam R. Howlett if (error) 2388763ecb03SLiam R. Howlett goto munmap_sidetree_failed; 2389763ecb03SLiam R. Howlett 2390763ecb03SLiam R. Howlett count++; 2391763ecb03SLiam R. Howlett #ifdef CONFIG_DEBUG_VM_MAPLE_TREE 2392763ecb03SLiam R. Howlett BUG_ON(next->vm_start < start); 2393763ecb03SLiam R. Howlett BUG_ON(next->vm_start > end); 2394763ecb03SLiam R. Howlett #endif 2395763ecb03SLiam R. Howlett } 2396763ecb03SLiam R. Howlett 2397763ecb03SLiam R. Howlett if (!next) 2398183654ceSLiam R. Howlett next = vma_next(vmi); 23991da177e4SLinus Torvalds 24002376dd7cSAndrea Arcangeli if (unlikely(uf)) { 24012376dd7cSAndrea Arcangeli /* 24022376dd7cSAndrea Arcangeli * If userfaultfd_unmap_prep returns an error the vmas 2403f0953a1bSIngo Molnar * will remain split, but userland will get a 24042376dd7cSAndrea Arcangeli * highly unexpected error anyway. This is no 24052376dd7cSAndrea Arcangeli * different than the case where the first of the two 24062376dd7cSAndrea Arcangeli * __split_vma fails, but we don't undo the first 24072376dd7cSAndrea Arcangeli * split, despite we could. This is unlikely enough 24082376dd7cSAndrea Arcangeli * failure that it's not worth optimizing it for. 24092376dd7cSAndrea Arcangeli */ 241069dbe6daSLiam R. Howlett error = userfaultfd_unmap_prep(mm, start, end, uf); 241111f9a21aSLiam R. Howlett 24122376dd7cSAndrea Arcangeli if (error) 2413d4af56c5SLiam R. Howlett goto userfaultfd_error; 24142376dd7cSAndrea Arcangeli } 24152376dd7cSAndrea Arcangeli 2416763ecb03SLiam R. Howlett #if defined(CONFIG_DEBUG_VM_MAPLE_TREE) 2417763ecb03SLiam R. Howlett /* Make sure no VMAs are about to be lost. */ 2418763ecb03SLiam R. Howlett { 2419763ecb03SLiam R. Howlett MA_STATE(test, &mt_detach, start, end - 1); 2420763ecb03SLiam R. Howlett struct vm_area_struct *vma_mas, *vma_test; 2421763ecb03SLiam R. Howlett int test_count = 0; 2422763ecb03SLiam R. Howlett 2423183654ceSLiam R. Howlett vma_iter_set(vmi, start); 2424763ecb03SLiam R. Howlett rcu_read_lock(); 2425763ecb03SLiam R. Howlett vma_test = mas_find(&test, end - 1); 2426183654ceSLiam R. Howlett for_each_vma_range(*vmi, vma_mas, end) { 2427763ecb03SLiam R. Howlett BUG_ON(vma_mas != vma_test); 2428763ecb03SLiam R. Howlett test_count++; 2429763ecb03SLiam R. Howlett vma_test = mas_next(&test, end - 1); 2430763ecb03SLiam R. Howlett } 2431763ecb03SLiam R. Howlett rcu_read_unlock(); 2432763ecb03SLiam R. Howlett BUG_ON(count != test_count); 2433763ecb03SLiam R. Howlett } 2434763ecb03SLiam R. Howlett #endif 24350378c0a0SLiam R. Howlett /* Point of no return */ 2436183654ceSLiam R. Howlett vma_iter_set(vmi, start); 2437183654ceSLiam R. Howlett if (vma_iter_clear_gfp(vmi, start, end, GFP_KERNEL)) 24380378c0a0SLiam R. Howlett return -ENOMEM; 24390378c0a0SLiam R. Howlett 2440763ecb03SLiam R. Howlett mm->map_count -= count; 244111f9a21aSLiam R. Howlett /* 244211f9a21aSLiam R. Howlett * Do not downgrade mmap_lock if we are next to VM_GROWSDOWN or 244311f9a21aSLiam R. Howlett * VM_GROWSUP VMA. Such VMAs can change their size under 244411f9a21aSLiam R. Howlett * down_read(mmap_lock) and collide with the VMA we are about to unmap. 244511f9a21aSLiam R. Howlett */ 244611f9a21aSLiam R. Howlett if (downgrade) { 2447763ecb03SLiam R. Howlett if (next && (next->vm_flags & VM_GROWSDOWN)) 244811f9a21aSLiam R. Howlett downgrade = false; 244911f9a21aSLiam R. Howlett else if (prev && (prev->vm_flags & VM_GROWSUP)) 245011f9a21aSLiam R. Howlett downgrade = false; 245111f9a21aSLiam R. Howlett else 2452d8ed45c5SMichel Lespinasse mmap_write_downgrade(mm); 245311f9a21aSLiam R. Howlett } 2454dd2283f2SYang Shi 2455763ecb03SLiam R. Howlett unmap_region(mm, &mt_detach, vma, prev, next, start, end); 2456763ecb03SLiam R. Howlett /* Statistics and freeing VMAs */ 2457763ecb03SLiam R. Howlett mas_set(&mas_detach, start); 2458763ecb03SLiam R. Howlett remove_mt(mm, &mas_detach); 2459763ecb03SLiam R. Howlett __mt_destroy(&mt_detach); 24601da177e4SLinus Torvalds 2461524e00b3SLiam R. Howlett 2462524e00b3SLiam R. Howlett validate_mm(mm); 2463dd2283f2SYang Shi return downgrade ? 1 : 0; 2464d4af56c5SLiam R. Howlett 2465d4af56c5SLiam R. Howlett userfaultfd_error: 2466763ecb03SLiam R. Howlett munmap_sidetree_failed: 2467763ecb03SLiam R. Howlett end_split_failed: 2468763ecb03SLiam R. Howlett __mt_destroy(&mt_detach); 2469763ecb03SLiam R. Howlett start_split_failed: 2470763ecb03SLiam R. Howlett map_count_exceeded: 2471d4af56c5SLiam R. Howlett return error; 24721da177e4SLinus Torvalds } 24731da177e4SLinus Torvalds 247411f9a21aSLiam R. Howlett /* 2475183654ceSLiam R. Howlett * do_vmi_munmap() - munmap a given range. 2476183654ceSLiam R. Howlett * @vmi: The vma iterator 247711f9a21aSLiam R. Howlett * @mm: The mm_struct 247811f9a21aSLiam R. Howlett * @start: The start address to munmap 247911f9a21aSLiam R. Howlett * @len: The length of the range to munmap 248011f9a21aSLiam R. Howlett * @uf: The userfaultfd list_head 248111f9a21aSLiam R. Howlett * @downgrade: set to true if the user wants to attempt to write_downgrade the 24828651a137SLorenzo Stoakes * mmap_lock 248311f9a21aSLiam R. Howlett * 248411f9a21aSLiam R. Howlett * This function takes a @mas that is either pointing to the previous VMA or set 248511f9a21aSLiam R. Howlett * to MA_START and sets it up to remove the mapping(s). The @len will be 248611f9a21aSLiam R. Howlett * aligned and any arch_unmap work will be preformed. 248711f9a21aSLiam R. Howlett * 248811f9a21aSLiam R. Howlett * Returns: -EINVAL on failure, 1 on success and unlock, 0 otherwise. 248911f9a21aSLiam R. Howlett */ 2490183654ceSLiam R. Howlett int do_vmi_munmap(struct vma_iterator *vmi, struct mm_struct *mm, 249111f9a21aSLiam R. Howlett unsigned long start, size_t len, struct list_head *uf, 249211f9a21aSLiam R. Howlett bool downgrade) 249311f9a21aSLiam R. Howlett { 249411f9a21aSLiam R. Howlett unsigned long end; 249511f9a21aSLiam R. Howlett struct vm_area_struct *vma; 249611f9a21aSLiam R. Howlett 249711f9a21aSLiam R. Howlett if ((offset_in_page(start)) || start > TASK_SIZE || len > TASK_SIZE-start) 249811f9a21aSLiam R. Howlett return -EINVAL; 249911f9a21aSLiam R. Howlett 250011f9a21aSLiam R. Howlett end = start + PAGE_ALIGN(len); 250111f9a21aSLiam R. Howlett if (end == start) 250211f9a21aSLiam R. Howlett return -EINVAL; 250311f9a21aSLiam R. Howlett 250411f9a21aSLiam R. Howlett /* arch_unmap() might do unmaps itself. */ 250511f9a21aSLiam R. Howlett arch_unmap(mm, start, end); 250611f9a21aSLiam R. Howlett 250711f9a21aSLiam R. Howlett /* Find the first overlapping VMA */ 2508183654ceSLiam R. Howlett vma = vma_find(vmi, end); 250911f9a21aSLiam R. Howlett if (!vma) 251011f9a21aSLiam R. Howlett return 0; 251111f9a21aSLiam R. Howlett 2512183654ceSLiam R. Howlett return do_vmi_align_munmap(vmi, vma, mm, start, end, uf, downgrade); 251311f9a21aSLiam R. Howlett } 251411f9a21aSLiam R. Howlett 251511f9a21aSLiam R. Howlett /* do_munmap() - Wrapper function for non-maple tree aware do_munmap() calls. 251611f9a21aSLiam R. Howlett * @mm: The mm_struct 251711f9a21aSLiam R. Howlett * @start: The start address to munmap 251811f9a21aSLiam R. Howlett * @len: The length to be munmapped. 251911f9a21aSLiam R. Howlett * @uf: The userfaultfd list_head 252011f9a21aSLiam R. Howlett */ 2521dd2283f2SYang Shi int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, 2522dd2283f2SYang Shi struct list_head *uf) 2523dd2283f2SYang Shi { 2524183654ceSLiam R. Howlett VMA_ITERATOR(vmi, mm, start); 252511f9a21aSLiam R. Howlett 2526183654ceSLiam R. Howlett return do_vmi_munmap(&vmi, mm, start, len, uf, false); 2527dd2283f2SYang Shi } 2528dd2283f2SYang Shi 2529e99668a5SLiam R. Howlett unsigned long mmap_region(struct file *file, unsigned long addr, 2530e99668a5SLiam R. Howlett unsigned long len, vm_flags_t vm_flags, unsigned long pgoff, 2531e99668a5SLiam R. Howlett struct list_head *uf) 2532e99668a5SLiam R. Howlett { 2533e99668a5SLiam R. Howlett struct mm_struct *mm = current->mm; 2534e99668a5SLiam R. Howlett struct vm_area_struct *vma = NULL; 2535e99668a5SLiam R. Howlett struct vm_area_struct *next, *prev, *merge; 2536e99668a5SLiam R. Howlett pgoff_t pglen = len >> PAGE_SHIFT; 2537e99668a5SLiam R. Howlett unsigned long charged = 0; 2538e99668a5SLiam R. Howlett unsigned long end = addr + len; 2539e99668a5SLiam R. Howlett unsigned long merge_start = addr, merge_end = end; 2540e99668a5SLiam R. Howlett pgoff_t vm_pgoff; 2541e99668a5SLiam R. Howlett int error; 2542183654ceSLiam R. Howlett VMA_ITERATOR(vmi, mm, addr); 2543e99668a5SLiam R. Howlett 2544e99668a5SLiam R. Howlett /* Check against address space limit. */ 2545e99668a5SLiam R. Howlett if (!may_expand_vm(mm, vm_flags, len >> PAGE_SHIFT)) { 2546e99668a5SLiam R. Howlett unsigned long nr_pages; 2547e99668a5SLiam R. Howlett 2548e99668a5SLiam R. Howlett /* 2549e99668a5SLiam R. Howlett * MAP_FIXED may remove pages of mappings that intersects with 2550e99668a5SLiam R. Howlett * requested mapping. Account for the pages it would unmap. 2551e99668a5SLiam R. Howlett */ 2552e99668a5SLiam R. Howlett nr_pages = count_vma_pages_range(mm, addr, end); 2553e99668a5SLiam R. Howlett 2554e99668a5SLiam R. Howlett if (!may_expand_vm(mm, vm_flags, 2555e99668a5SLiam R. Howlett (len >> PAGE_SHIFT) - nr_pages)) 2556e99668a5SLiam R. Howlett return -ENOMEM; 2557e99668a5SLiam R. Howlett } 2558e99668a5SLiam R. Howlett 2559e99668a5SLiam R. Howlett /* Unmap any existing mapping in the area */ 2560183654ceSLiam R. Howlett if (do_vmi_munmap(&vmi, mm, addr, len, uf, false)) 2561e99668a5SLiam R. Howlett return -ENOMEM; 2562e99668a5SLiam R. Howlett 2563e99668a5SLiam R. Howlett /* 2564e99668a5SLiam R. Howlett * Private writable mapping: check memory availability 2565e99668a5SLiam R. Howlett */ 2566e99668a5SLiam R. Howlett if (accountable_mapping(file, vm_flags)) { 2567e99668a5SLiam R. Howlett charged = len >> PAGE_SHIFT; 2568e99668a5SLiam R. Howlett if (security_vm_enough_memory_mm(mm, charged)) 2569e99668a5SLiam R. Howlett return -ENOMEM; 2570e99668a5SLiam R. Howlett vm_flags |= VM_ACCOUNT; 2571e99668a5SLiam R. Howlett } 2572e99668a5SLiam R. Howlett 2573183654ceSLiam R. Howlett next = vma_next(&vmi); 2574183654ceSLiam R. Howlett prev = vma_prev(&vmi); 2575e99668a5SLiam R. Howlett if (vm_flags & VM_SPECIAL) 2576e99668a5SLiam R. Howlett goto cannot_expand; 2577e99668a5SLiam R. Howlett 2578e99668a5SLiam R. Howlett /* Attempt to expand an old mapping */ 2579e99668a5SLiam R. Howlett /* Check next */ 2580e99668a5SLiam R. Howlett if (next && next->vm_start == end && !vma_policy(next) && 2581e99668a5SLiam R. Howlett can_vma_merge_before(next, vm_flags, NULL, file, pgoff+pglen, 2582e99668a5SLiam R. Howlett NULL_VM_UFFD_CTX, NULL)) { 2583e99668a5SLiam R. Howlett merge_end = next->vm_end; 2584e99668a5SLiam R. Howlett vma = next; 2585e99668a5SLiam R. Howlett vm_pgoff = next->vm_pgoff - pglen; 2586e99668a5SLiam R. Howlett } 2587e99668a5SLiam R. Howlett 2588e99668a5SLiam R. Howlett /* Check prev */ 2589e99668a5SLiam R. Howlett if (prev && prev->vm_end == addr && !vma_policy(prev) && 2590e99668a5SLiam R. Howlett (vma ? can_vma_merge_after(prev, vm_flags, vma->anon_vma, file, 2591e99668a5SLiam R. Howlett pgoff, vma->vm_userfaultfd_ctx, NULL) : 2592e99668a5SLiam R. Howlett can_vma_merge_after(prev, vm_flags, NULL, file, pgoff, 2593e99668a5SLiam R. Howlett NULL_VM_UFFD_CTX, NULL))) { 2594e99668a5SLiam R. Howlett merge_start = prev->vm_start; 2595e99668a5SLiam R. Howlett vma = prev; 2596e99668a5SLiam R. Howlett vm_pgoff = prev->vm_pgoff; 2597e99668a5SLiam R. Howlett } 2598e99668a5SLiam R. Howlett 2599e99668a5SLiam R. Howlett 2600e99668a5SLiam R. Howlett /* Actually expand, if possible */ 2601e99668a5SLiam R. Howlett if (vma && 2602*3c441ab7SLiam R. Howlett !vma_expand(&vmi, vma, merge_start, merge_end, vm_pgoff, next)) { 2603e99668a5SLiam R. Howlett khugepaged_enter_vma(vma, vm_flags); 2604e99668a5SLiam R. Howlett goto expanded; 2605e99668a5SLiam R. Howlett } 2606e99668a5SLiam R. Howlett 2607e99668a5SLiam R. Howlett cannot_expand: 2608e99668a5SLiam R. Howlett /* 2609e99668a5SLiam R. Howlett * Determine the object being mapped and call the appropriate 2610e99668a5SLiam R. Howlett * specific mapper. the address has already been validated, but 2611e99668a5SLiam R. Howlett * not unmapped, but the maps are removed from the list. 2612e99668a5SLiam R. Howlett */ 2613e99668a5SLiam R. Howlett vma = vm_area_alloc(mm); 2614e99668a5SLiam R. Howlett if (!vma) { 2615e99668a5SLiam R. Howlett error = -ENOMEM; 2616e99668a5SLiam R. Howlett goto unacct_error; 2617e99668a5SLiam R. Howlett } 2618e99668a5SLiam R. Howlett 2619e99668a5SLiam R. Howlett vma->vm_start = addr; 2620e99668a5SLiam R. Howlett vma->vm_end = end; 2621e99668a5SLiam R. Howlett vma->vm_flags = vm_flags; 2622e99668a5SLiam R. Howlett vma->vm_page_prot = vm_get_page_prot(vm_flags); 2623e99668a5SLiam R. Howlett vma->vm_pgoff = pgoff; 2624e99668a5SLiam R. Howlett 2625e99668a5SLiam R. Howlett if (file) { 2626e99668a5SLiam R. Howlett if (vm_flags & VM_SHARED) { 2627e99668a5SLiam R. Howlett error = mapping_map_writable(file->f_mapping); 2628e99668a5SLiam R. Howlett if (error) 2629e99668a5SLiam R. Howlett goto free_vma; 2630e99668a5SLiam R. Howlett } 2631e99668a5SLiam R. Howlett 2632e99668a5SLiam R. Howlett vma->vm_file = get_file(file); 2633e99668a5SLiam R. Howlett error = call_mmap(file, vma); 2634e99668a5SLiam R. Howlett if (error) 2635e99668a5SLiam R. Howlett goto unmap_and_free_vma; 2636e99668a5SLiam R. Howlett 2637a57b7051SLiam Howlett /* 2638a57b7051SLiam Howlett * Expansion is handled above, merging is handled below. 2639a57b7051SLiam Howlett * Drivers should not alter the address of the VMA. 2640e99668a5SLiam R. Howlett */ 2641a57b7051SLiam Howlett if (WARN_ON((addr != vma->vm_start))) { 2642a57b7051SLiam Howlett error = -EINVAL; 2643a57b7051SLiam Howlett goto close_and_free_vma; 2644a57b7051SLiam Howlett } 2645183654ceSLiam R. Howlett vma_iter_set(&vmi, addr); 2646e99668a5SLiam R. Howlett 2647e99668a5SLiam R. Howlett /* 2648e99668a5SLiam R. Howlett * If vm_flags changed after call_mmap(), we should try merge 2649e99668a5SLiam R. Howlett * vma again as we may succeed this time. 2650e99668a5SLiam R. Howlett */ 2651e99668a5SLiam R. Howlett if (unlikely(vm_flags != vma->vm_flags && prev)) { 2652e99668a5SLiam R. Howlett merge = vma_merge(mm, prev, vma->vm_start, vma->vm_end, vma->vm_flags, 2653e99668a5SLiam R. Howlett NULL, vma->vm_file, vma->vm_pgoff, NULL, NULL_VM_UFFD_CTX, NULL); 2654e99668a5SLiam R. Howlett if (merge) { 2655e99668a5SLiam R. Howlett /* 2656e99668a5SLiam R. Howlett * ->mmap() can change vma->vm_file and fput 2657e99668a5SLiam R. Howlett * the original file. So fput the vma->vm_file 2658e99668a5SLiam R. Howlett * here or we would add an extra fput for file 2659e99668a5SLiam R. Howlett * and cause general protection fault 2660e99668a5SLiam R. Howlett * ultimately. 2661e99668a5SLiam R. Howlett */ 2662e99668a5SLiam R. Howlett fput(vma->vm_file); 2663e99668a5SLiam R. Howlett vm_area_free(vma); 2664e99668a5SLiam R. Howlett vma = merge; 2665e99668a5SLiam R. Howlett /* Update vm_flags to pick up the change. */ 2666e99668a5SLiam R. Howlett vm_flags = vma->vm_flags; 2667e99668a5SLiam R. Howlett goto unmap_writable; 2668e99668a5SLiam R. Howlett } 2669e99668a5SLiam R. Howlett } 2670e99668a5SLiam R. Howlett 2671e99668a5SLiam R. Howlett vm_flags = vma->vm_flags; 2672e99668a5SLiam R. Howlett } else if (vm_flags & VM_SHARED) { 2673e99668a5SLiam R. Howlett error = shmem_zero_setup(vma); 2674e99668a5SLiam R. Howlett if (error) 2675e99668a5SLiam R. Howlett goto free_vma; 2676e99668a5SLiam R. Howlett } else { 2677e99668a5SLiam R. Howlett vma_set_anonymous(vma); 2678e99668a5SLiam R. Howlett } 2679e99668a5SLiam R. Howlett 2680b507808eSJoey Gouly if (map_deny_write_exec(vma, vma->vm_flags)) { 2681b507808eSJoey Gouly error = -EACCES; 2682b507808eSJoey Gouly if (file) 2683b507808eSJoey Gouly goto close_and_free_vma; 2684b507808eSJoey Gouly else if (vma->vm_file) 2685b507808eSJoey Gouly goto unmap_and_free_vma; 2686b507808eSJoey Gouly else 2687b507808eSJoey Gouly goto free_vma; 2688b507808eSJoey Gouly } 2689b507808eSJoey Gouly 2690e99668a5SLiam R. Howlett /* Allow architectures to sanity-check the vm_flags */ 2691e99668a5SLiam R. Howlett if (!arch_validate_flags(vma->vm_flags)) { 2692e99668a5SLiam R. Howlett error = -EINVAL; 2693e99668a5SLiam R. Howlett if (file) 2694deb0f656SCarlos Llamas goto close_and_free_vma; 2695cc674ab3SLi Zetao else if (vma->vm_file) 2696cc674ab3SLi Zetao goto unmap_and_free_vma; 2697e99668a5SLiam R. Howlett else 2698e99668a5SLiam R. Howlett goto free_vma; 2699e99668a5SLiam R. Howlett } 2700e99668a5SLiam R. Howlett 2701183654ceSLiam R. Howlett if (vma_iter_prealloc(&vmi)) { 2702e99668a5SLiam R. Howlett error = -ENOMEM; 2703e99668a5SLiam R. Howlett if (file) 27045789151eSMike Kravetz goto close_and_free_vma; 2705cc674ab3SLi Zetao else if (vma->vm_file) 2706cc674ab3SLi Zetao goto unmap_and_free_vma; 2707e99668a5SLiam R. Howlett else 2708e99668a5SLiam R. Howlett goto free_vma; 2709e99668a5SLiam R. Howlett } 2710e99668a5SLiam R. Howlett 2711e99668a5SLiam R. Howlett if (vma->vm_file) 2712e99668a5SLiam R. Howlett i_mmap_lock_write(vma->vm_file->f_mapping); 2713e99668a5SLiam R. Howlett 2714183654ceSLiam R. Howlett vma_iter_store(&vmi, vma); 2715e99668a5SLiam R. Howlett mm->map_count++; 2716e99668a5SLiam R. Howlett if (vma->vm_file) { 2717e99668a5SLiam R. Howlett if (vma->vm_flags & VM_SHARED) 2718e99668a5SLiam R. Howlett mapping_allow_writable(vma->vm_file->f_mapping); 2719e99668a5SLiam R. Howlett 2720e99668a5SLiam R. Howlett flush_dcache_mmap_lock(vma->vm_file->f_mapping); 2721e99668a5SLiam R. Howlett vma_interval_tree_insert(vma, &vma->vm_file->f_mapping->i_mmap); 2722e99668a5SLiam R. Howlett flush_dcache_mmap_unlock(vma->vm_file->f_mapping); 2723e99668a5SLiam R. Howlett i_mmap_unlock_write(vma->vm_file->f_mapping); 2724e99668a5SLiam R. Howlett } 2725e99668a5SLiam R. Howlett 2726e99668a5SLiam R. Howlett /* 2727e99668a5SLiam R. Howlett * vma_merge() calls khugepaged_enter_vma() either, the below 2728e99668a5SLiam R. Howlett * call covers the non-merge case. 2729e99668a5SLiam R. Howlett */ 2730e99668a5SLiam R. Howlett khugepaged_enter_vma(vma, vma->vm_flags); 2731e99668a5SLiam R. Howlett 2732e99668a5SLiam R. Howlett /* Once vma denies write, undo our temporary denial count */ 2733e99668a5SLiam R. Howlett unmap_writable: 2734e99668a5SLiam R. Howlett if (file && vm_flags & VM_SHARED) 2735e99668a5SLiam R. Howlett mapping_unmap_writable(file->f_mapping); 2736e99668a5SLiam R. Howlett file = vma->vm_file; 2737e99668a5SLiam R. Howlett expanded: 2738e99668a5SLiam R. Howlett perf_event_mmap(vma); 2739e99668a5SLiam R. Howlett 2740e99668a5SLiam R. Howlett vm_stat_account(mm, vm_flags, len >> PAGE_SHIFT); 2741e99668a5SLiam R. Howlett if (vm_flags & VM_LOCKED) { 2742e99668a5SLiam R. Howlett if ((vm_flags & VM_SPECIAL) || vma_is_dax(vma) || 2743e99668a5SLiam R. Howlett is_vm_hugetlb_page(vma) || 2744e99668a5SLiam R. Howlett vma == get_gate_vma(current->mm)) 2745e99668a5SLiam R. Howlett vma->vm_flags &= VM_LOCKED_CLEAR_MASK; 2746e99668a5SLiam R. Howlett else 2747e99668a5SLiam R. Howlett mm->locked_vm += (len >> PAGE_SHIFT); 2748e99668a5SLiam R. Howlett } 2749e99668a5SLiam R. Howlett 2750e99668a5SLiam R. Howlett if (file) 2751e99668a5SLiam R. Howlett uprobe_mmap(vma); 2752e99668a5SLiam R. Howlett 2753e99668a5SLiam R. Howlett /* 2754e99668a5SLiam R. Howlett * New (or expanded) vma always get soft dirty status. 2755e99668a5SLiam R. Howlett * Otherwise user-space soft-dirty page tracker won't 2756e99668a5SLiam R. Howlett * be able to distinguish situation when vma area unmapped, 2757e99668a5SLiam R. Howlett * then new mapped in-place (which must be aimed as 2758e99668a5SLiam R. Howlett * a completely new data area). 2759e99668a5SLiam R. Howlett */ 2760e99668a5SLiam R. Howlett vma->vm_flags |= VM_SOFTDIRTY; 2761e99668a5SLiam R. Howlett 2762e99668a5SLiam R. Howlett vma_set_page_prot(vma); 2763e99668a5SLiam R. Howlett 2764e99668a5SLiam R. Howlett validate_mm(mm); 2765e99668a5SLiam R. Howlett return addr; 2766e99668a5SLiam R. Howlett 2767deb0f656SCarlos Llamas close_and_free_vma: 2768deb0f656SCarlos Llamas if (vma->vm_ops && vma->vm_ops->close) 2769deb0f656SCarlos Llamas vma->vm_ops->close(vma); 2770e99668a5SLiam R. Howlett unmap_and_free_vma: 2771e99668a5SLiam R. Howlett fput(vma->vm_file); 2772e99668a5SLiam R. Howlett vma->vm_file = NULL; 2773e99668a5SLiam R. Howlett 2774e99668a5SLiam R. Howlett /* Undo any partial mapping done by a device driver. */ 2775183654ceSLiam R. Howlett unmap_region(mm, &mm->mm_mt, vma, prev, next, vma->vm_start, vma->vm_end); 2776cc674ab3SLi Zetao if (file && (vm_flags & VM_SHARED)) 2777e99668a5SLiam R. Howlett mapping_unmap_writable(file->f_mapping); 2778e99668a5SLiam R. Howlett free_vma: 2779e99668a5SLiam R. Howlett vm_area_free(vma); 2780e99668a5SLiam R. Howlett unacct_error: 2781e99668a5SLiam R. Howlett if (charged) 2782e99668a5SLiam R. Howlett vm_unacct_memory(charged); 2783e99668a5SLiam R. Howlett validate_mm(mm); 2784e99668a5SLiam R. Howlett return error; 2785e99668a5SLiam R. Howlett } 2786e99668a5SLiam R. Howlett 2787dd2283f2SYang Shi static int __vm_munmap(unsigned long start, size_t len, bool downgrade) 2788a46ef99dSLinus Torvalds { 2789a46ef99dSLinus Torvalds int ret; 2790bfce281cSAl Viro struct mm_struct *mm = current->mm; 2791897ab3e0SMike Rapoport LIST_HEAD(uf); 2792183654ceSLiam R. Howlett VMA_ITERATOR(vmi, mm, start); 2793a46ef99dSLinus Torvalds 2794d8ed45c5SMichel Lespinasse if (mmap_write_lock_killable(mm)) 2795ae798783SMichal Hocko return -EINTR; 2796ae798783SMichal Hocko 2797183654ceSLiam R. Howlett ret = do_vmi_munmap(&vmi, mm, start, len, &uf, downgrade); 2798dd2283f2SYang Shi /* 2799c1e8d7c6SMichel Lespinasse * Returning 1 indicates mmap_lock is downgraded. 2800dd2283f2SYang Shi * But 1 is not legal return value of vm_munmap() and munmap(), reset 2801dd2283f2SYang Shi * it to 0 before return. 2802dd2283f2SYang Shi */ 2803dd2283f2SYang Shi if (ret == 1) { 2804d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 2805dd2283f2SYang Shi ret = 0; 2806dd2283f2SYang Shi } else 2807d8ed45c5SMichel Lespinasse mmap_write_unlock(mm); 2808dd2283f2SYang Shi 2809897ab3e0SMike Rapoport userfaultfd_unmap_complete(mm, &uf); 2810a46ef99dSLinus Torvalds return ret; 2811a46ef99dSLinus Torvalds } 2812dd2283f2SYang Shi 2813dd2283f2SYang Shi int vm_munmap(unsigned long start, size_t len) 2814dd2283f2SYang Shi { 2815dd2283f2SYang Shi return __vm_munmap(start, len, false); 2816dd2283f2SYang Shi } 2817a46ef99dSLinus Torvalds EXPORT_SYMBOL(vm_munmap); 2818a46ef99dSLinus Torvalds 28196a6160a7SHeiko Carstens SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) 28201da177e4SLinus Torvalds { 2821ce18d171SCatalin Marinas addr = untagged_addr(addr); 2822dd2283f2SYang Shi return __vm_munmap(addr, len, true); 28231da177e4SLinus Torvalds } 28241da177e4SLinus Torvalds 2825c8d78c18SKirill A. Shutemov 2826c8d78c18SKirill A. Shutemov /* 2827c8d78c18SKirill A. Shutemov * Emulation of deprecated remap_file_pages() syscall. 2828c8d78c18SKirill A. Shutemov */ 2829c8d78c18SKirill A. Shutemov SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size, 2830c8d78c18SKirill A. Shutemov unsigned long, prot, unsigned long, pgoff, unsigned long, flags) 2831c8d78c18SKirill A. Shutemov { 2832c8d78c18SKirill A. Shutemov 2833c8d78c18SKirill A. Shutemov struct mm_struct *mm = current->mm; 2834c8d78c18SKirill A. Shutemov struct vm_area_struct *vma; 2835c8d78c18SKirill A. Shutemov unsigned long populate = 0; 2836c8d78c18SKirill A. Shutemov unsigned long ret = -EINVAL; 2837c8d78c18SKirill A. Shutemov struct file *file; 2838c8d78c18SKirill A. Shutemov 2839ee65728eSMike Rapoport pr_warn_once("%s (%d) uses deprecated remap_file_pages() syscall. See Documentation/mm/remap_file_pages.rst.\n", 2840c8d78c18SKirill A. Shutemov current->comm, current->pid); 2841c8d78c18SKirill A. Shutemov 2842c8d78c18SKirill A. Shutemov if (prot) 2843c8d78c18SKirill A. Shutemov return ret; 2844c8d78c18SKirill A. Shutemov start = start & PAGE_MASK; 2845c8d78c18SKirill A. Shutemov size = size & PAGE_MASK; 2846c8d78c18SKirill A. Shutemov 2847c8d78c18SKirill A. Shutemov if (start + size <= start) 2848c8d78c18SKirill A. Shutemov return ret; 2849c8d78c18SKirill A. Shutemov 2850c8d78c18SKirill A. Shutemov /* Does pgoff wrap? */ 2851c8d78c18SKirill A. Shutemov if (pgoff + (size >> PAGE_SHIFT) < pgoff) 2852c8d78c18SKirill A. Shutemov return ret; 2853c8d78c18SKirill A. Shutemov 2854d8ed45c5SMichel Lespinasse if (mmap_write_lock_killable(mm)) 2855dc0ef0dfSMichal Hocko return -EINTR; 2856dc0ef0dfSMichal Hocko 28579b593cb2SLiam R. Howlett vma = vma_lookup(mm, start); 2858c8d78c18SKirill A. Shutemov 2859c8d78c18SKirill A. Shutemov if (!vma || !(vma->vm_flags & VM_SHARED)) 2860c8d78c18SKirill A. Shutemov goto out; 2861c8d78c18SKirill A. Shutemov 286248f7df32SKirill A. Shutemov if (start + size > vma->vm_end) { 2863763ecb03SLiam R. Howlett VMA_ITERATOR(vmi, mm, vma->vm_end); 2864763ecb03SLiam R. Howlett struct vm_area_struct *next, *prev = vma; 286548f7df32SKirill A. Shutemov 2866763ecb03SLiam R. Howlett for_each_vma_range(vmi, next, start + size) { 286748f7df32SKirill A. Shutemov /* hole between vmas ? */ 2868763ecb03SLiam R. Howlett if (next->vm_start != prev->vm_end) 286948f7df32SKirill A. Shutemov goto out; 287048f7df32SKirill A. Shutemov 287148f7df32SKirill A. Shutemov if (next->vm_file != vma->vm_file) 287248f7df32SKirill A. Shutemov goto out; 287348f7df32SKirill A. Shutemov 287448f7df32SKirill A. Shutemov if (next->vm_flags != vma->vm_flags) 287548f7df32SKirill A. Shutemov goto out; 287648f7df32SKirill A. Shutemov 28771db43d3fSLiam Howlett if (start + size <= next->vm_end) 28781db43d3fSLiam Howlett break; 28791db43d3fSLiam Howlett 2880763ecb03SLiam R. Howlett prev = next; 288148f7df32SKirill A. Shutemov } 288248f7df32SKirill A. Shutemov 288348f7df32SKirill A. Shutemov if (!next) 2884c8d78c18SKirill A. Shutemov goto out; 2885c8d78c18SKirill A. Shutemov } 2886c8d78c18SKirill A. Shutemov 2887c8d78c18SKirill A. Shutemov prot |= vma->vm_flags & VM_READ ? PROT_READ : 0; 2888c8d78c18SKirill A. Shutemov prot |= vma->vm_flags & VM_WRITE ? PROT_WRITE : 0; 2889c8d78c18SKirill A. Shutemov prot |= vma->vm_flags & VM_EXEC ? PROT_EXEC : 0; 2890c8d78c18SKirill A. Shutemov 2891c8d78c18SKirill A. Shutemov flags &= MAP_NONBLOCK; 2892c8d78c18SKirill A. Shutemov flags |= MAP_SHARED | MAP_FIXED | MAP_POPULATE; 2893fce000b1SLiam Howlett if (vma->vm_flags & VM_LOCKED) 2894c8d78c18SKirill A. Shutemov flags |= MAP_LOCKED; 289548f7df32SKirill A. Shutemov 2896c8d78c18SKirill A. Shutemov file = get_file(vma->vm_file); 289745e55300SPeter Collingbourne ret = do_mmap(vma->vm_file, start, size, 2898897ab3e0SMike Rapoport prot, flags, pgoff, &populate, NULL); 2899c8d78c18SKirill A. Shutemov fput(file); 2900c8d78c18SKirill A. Shutemov out: 2901d8ed45c5SMichel Lespinasse mmap_write_unlock(mm); 2902c8d78c18SKirill A. Shutemov if (populate) 2903c8d78c18SKirill A. Shutemov mm_populate(ret, populate); 2904c8d78c18SKirill A. Shutemov if (!IS_ERR_VALUE(ret)) 2905c8d78c18SKirill A. Shutemov ret = 0; 2906c8d78c18SKirill A. Shutemov return ret; 2907c8d78c18SKirill A. Shutemov } 2908c8d78c18SKirill A. Shutemov 29091da177e4SLinus Torvalds /* 291092fed820SLiam R. Howlett * brk_munmap() - Unmap a full or partial vma. 291192fed820SLiam R. Howlett * @vmi: The vma iterator 29122e7ce7d3SLiam R. Howlett * @vma: The vma to be modified 29132e7ce7d3SLiam R. Howlett * @newbrk: the start of the address to unmap 29142e7ce7d3SLiam R. Howlett * @oldbrk: The end of the address to unmap 29152e7ce7d3SLiam R. Howlett * @uf: The userfaultfd list_head 29162e7ce7d3SLiam R. Howlett * 29172e7ce7d3SLiam R. Howlett * Returns: 1 on success. 29182e7ce7d3SLiam R. Howlett * unmaps a partial VMA mapping. Does not handle alignment, downgrades lock if 29192e7ce7d3SLiam R. Howlett * possible. 29201da177e4SLinus Torvalds */ 292192fed820SLiam R. Howlett static int do_brk_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma, 29222e7ce7d3SLiam R. Howlett unsigned long newbrk, unsigned long oldbrk, 29232e7ce7d3SLiam R. Howlett struct list_head *uf) 29242e7ce7d3SLiam R. Howlett { 29252e7ce7d3SLiam R. Howlett struct mm_struct *mm = vma->vm_mm; 29262e7ce7d3SLiam R. Howlett int ret; 29272e7ce7d3SLiam R. Howlett 29282e7ce7d3SLiam R. Howlett arch_unmap(mm, newbrk, oldbrk); 2929183654ceSLiam R. Howlett ret = do_vmi_align_munmap(vmi, vma, mm, newbrk, oldbrk, uf, true); 29302e7ce7d3SLiam R. Howlett validate_mm_mt(mm); 29312e7ce7d3SLiam R. Howlett return ret; 29322e7ce7d3SLiam R. Howlett } 29332e7ce7d3SLiam R. Howlett 29342e7ce7d3SLiam R. Howlett /* 29352e7ce7d3SLiam R. Howlett * do_brk_flags() - Increase the brk vma if the flags match. 293692fed820SLiam R. Howlett * @vmi: The vma iterator 29372e7ce7d3SLiam R. Howlett * @addr: The start address 29382e7ce7d3SLiam R. Howlett * @len: The length of the increase 29392e7ce7d3SLiam R. Howlett * @vma: The vma, 29402e7ce7d3SLiam R. Howlett * @flags: The VMA Flags 29412e7ce7d3SLiam R. Howlett * 29422e7ce7d3SLiam R. Howlett * Extend the brk VMA from addr to addr + len. If the VMA is NULL or the flags 29432e7ce7d3SLiam R. Howlett * do not match then create a new anonymous VMA. Eventually we may be able to 29442e7ce7d3SLiam R. Howlett * do some brk-specific accounting here. 29452e7ce7d3SLiam R. Howlett */ 294692fed820SLiam R. Howlett static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma, 2947763ecb03SLiam R. Howlett unsigned long addr, unsigned long len, unsigned long flags) 29481da177e4SLinus Torvalds { 29491da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 29502e7ce7d3SLiam R. Howlett 2951d4af56c5SLiam R. Howlett validate_mm_mt(mm); 29522e7ce7d3SLiam R. Howlett /* 29532e7ce7d3SLiam R. Howlett * Check against address space limits by the changed size 29542e7ce7d3SLiam R. Howlett * Note: This happens *after* clearing old mappings in some code paths. 29552e7ce7d3SLiam R. Howlett */ 295616e72e9bSDenys Vlasenko flags |= VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; 295784638335SKonstantin Khlebnikov if (!may_expand_vm(mm, flags, len >> PAGE_SHIFT)) 29581da177e4SLinus Torvalds return -ENOMEM; 29591da177e4SLinus Torvalds 29601da177e4SLinus Torvalds if (mm->map_count > sysctl_max_map_count) 29611da177e4SLinus Torvalds return -ENOMEM; 29621da177e4SLinus Torvalds 2963191c5424SAl Viro if (security_vm_enough_memory_mm(mm, len >> PAGE_SHIFT)) 29641da177e4SLinus Torvalds return -ENOMEM; 29651da177e4SLinus Torvalds 29661da177e4SLinus Torvalds /* 29672e7ce7d3SLiam R. Howlett * Expand the existing vma if possible; Note that singular lists do not 29682e7ce7d3SLiam R. Howlett * occur after forking, so the expand will only happen on new VMAs. 29691da177e4SLinus Torvalds */ 29706c28ca64SLiam Howlett if (vma && vma->vm_end == addr && !vma_policy(vma) && 29716c28ca64SLiam Howlett can_vma_merge_after(vma, flags, NULL, NULL, 29726c28ca64SLiam Howlett addr >> PAGE_SHIFT, NULL_VM_UFFD_CTX, NULL)) { 297392fed820SLiam R. Howlett if (vma_iter_prealloc(vmi)) 2974675eaca1SAlistair Popple goto unacct_fail; 297528c5609fSLiam Howlett 297628c5609fSLiam Howlett vma_adjust_trans_huge(vma, vma->vm_start, addr + len, 0); 29772e7ce7d3SLiam R. Howlett if (vma->anon_vma) { 29782e7ce7d3SLiam R. Howlett anon_vma_lock_write(vma->anon_vma); 29792e7ce7d3SLiam R. Howlett anon_vma_interval_tree_pre_update_vma(vma); 29801da177e4SLinus Torvalds } 29812e7ce7d3SLiam R. Howlett vma->vm_end = addr + len; 29822e7ce7d3SLiam R. Howlett vma->vm_flags |= VM_SOFTDIRTY; 298392fed820SLiam R. Howlett vma_iter_store(vmi, vma); 29842e7ce7d3SLiam R. Howlett 29852e7ce7d3SLiam R. Howlett if (vma->anon_vma) { 29862e7ce7d3SLiam R. Howlett anon_vma_interval_tree_post_update_vma(vma); 29872e7ce7d3SLiam R. Howlett anon_vma_unlock_write(vma->anon_vma); 29882e7ce7d3SLiam R. Howlett } 29892e7ce7d3SLiam R. Howlett khugepaged_enter_vma(vma, flags); 29902e7ce7d3SLiam R. Howlett goto out; 29912e7ce7d3SLiam R. Howlett } 29922e7ce7d3SLiam R. Howlett 29932e7ce7d3SLiam R. Howlett /* create a vma struct for an anonymous mapping */ 29942e7ce7d3SLiam R. Howlett vma = vm_area_alloc(mm); 29952e7ce7d3SLiam R. Howlett if (!vma) 2996675eaca1SAlistair Popple goto unacct_fail; 29971da177e4SLinus Torvalds 2998bfd40eafSKirill A. Shutemov vma_set_anonymous(vma); 29991da177e4SLinus Torvalds vma->vm_start = addr; 30001da177e4SLinus Torvalds vma->vm_end = addr + len; 30012e7ce7d3SLiam R. Howlett vma->vm_pgoff = addr >> PAGE_SHIFT; 30021da177e4SLinus Torvalds vma->vm_flags = flags; 30033ed75eb8SColy Li vma->vm_page_prot = vm_get_page_prot(flags); 300492fed820SLiam R. Howlett if (vma_iter_store_gfp(vmi, vma, GFP_KERNEL)) 30052e7ce7d3SLiam R. Howlett goto mas_store_fail; 3006d4af56c5SLiam R. Howlett 30072e7ce7d3SLiam R. Howlett mm->map_count++; 30081da177e4SLinus Torvalds out: 30093af9e859SEric B Munson perf_event_mmap(vma); 30101da177e4SLinus Torvalds mm->total_vm += len >> PAGE_SHIFT; 301184638335SKonstantin Khlebnikov mm->data_vm += len >> PAGE_SHIFT; 3012128557ffSMichel Lespinasse if (flags & VM_LOCKED) 3013ba470de4SRik van Riel mm->locked_vm += (len >> PAGE_SHIFT); 3014d9104d1cSCyrill Gorcunov vma->vm_flags |= VM_SOFTDIRTY; 3015763ecb03SLiam R. Howlett validate_mm(mm); 30165d22fc25SLinus Torvalds return 0; 3017d4af56c5SLiam R. Howlett 30182e7ce7d3SLiam R. Howlett mas_store_fail: 3019d4af56c5SLiam R. Howlett vm_area_free(vma); 3020675eaca1SAlistair Popple unacct_fail: 30212e7ce7d3SLiam R. Howlett vm_unacct_memory(len >> PAGE_SHIFT); 30222e7ce7d3SLiam R. Howlett return -ENOMEM; 30231da177e4SLinus Torvalds } 30241da177e4SLinus Torvalds 3025bb177a73SMichal Hocko int vm_brk_flags(unsigned long addr, unsigned long request, unsigned long flags) 3026e4eb1ff6SLinus Torvalds { 3027e4eb1ff6SLinus Torvalds struct mm_struct *mm = current->mm; 30282e7ce7d3SLiam R. Howlett struct vm_area_struct *vma = NULL; 3029bb177a73SMichal Hocko unsigned long len; 30305d22fc25SLinus Torvalds int ret; 3031128557ffSMichel Lespinasse bool populate; 3032897ab3e0SMike Rapoport LIST_HEAD(uf); 303392fed820SLiam R. Howlett VMA_ITERATOR(vmi, mm, addr); 3034e4eb1ff6SLinus Torvalds 3035bb177a73SMichal Hocko len = PAGE_ALIGN(request); 3036bb177a73SMichal Hocko if (len < request) 3037bb177a73SMichal Hocko return -ENOMEM; 3038bb177a73SMichal Hocko if (!len) 3039bb177a73SMichal Hocko return 0; 3040bb177a73SMichal Hocko 3041d8ed45c5SMichel Lespinasse if (mmap_write_lock_killable(mm)) 30422d6c9282SMichal Hocko return -EINTR; 30432d6c9282SMichal Hocko 30442e7ce7d3SLiam R. Howlett /* Until we need other flags, refuse anything except VM_EXEC. */ 30452e7ce7d3SLiam R. Howlett if ((flags & (~VM_EXEC)) != 0) 30462e7ce7d3SLiam R. Howlett return -EINVAL; 30472e7ce7d3SLiam R. Howlett 30482e7ce7d3SLiam R. Howlett ret = check_brk_limits(addr, len); 30492e7ce7d3SLiam R. Howlett if (ret) 30502e7ce7d3SLiam R. Howlett goto limits_failed; 30512e7ce7d3SLiam R. Howlett 3052183654ceSLiam R. Howlett ret = do_vmi_munmap(&vmi, mm, addr, len, &uf, 0); 30532e7ce7d3SLiam R. Howlett if (ret) 30542e7ce7d3SLiam R. Howlett goto munmap_failed; 30552e7ce7d3SLiam R. Howlett 305692fed820SLiam R. Howlett vma = vma_prev(&vmi); 305792fed820SLiam R. Howlett ret = do_brk_flags(&vmi, vma, addr, len, flags); 3058128557ffSMichel Lespinasse populate = ((mm->def_flags & VM_LOCKED) != 0); 3059d8ed45c5SMichel Lespinasse mmap_write_unlock(mm); 3060897ab3e0SMike Rapoport userfaultfd_unmap_complete(mm, &uf); 30615d22fc25SLinus Torvalds if (populate && !ret) 3062128557ffSMichel Lespinasse mm_populate(addr, len); 3063e4eb1ff6SLinus Torvalds return ret; 30642e7ce7d3SLiam R. Howlett 30652e7ce7d3SLiam R. Howlett munmap_failed: 30662e7ce7d3SLiam R. Howlett limits_failed: 30672e7ce7d3SLiam R. Howlett mmap_write_unlock(mm); 30682e7ce7d3SLiam R. Howlett return ret; 3069e4eb1ff6SLinus Torvalds } 307016e72e9bSDenys Vlasenko EXPORT_SYMBOL(vm_brk_flags); 307116e72e9bSDenys Vlasenko 307216e72e9bSDenys Vlasenko int vm_brk(unsigned long addr, unsigned long len) 307316e72e9bSDenys Vlasenko { 307416e72e9bSDenys Vlasenko return vm_brk_flags(addr, len, 0); 307516e72e9bSDenys Vlasenko } 3076e4eb1ff6SLinus Torvalds EXPORT_SYMBOL(vm_brk); 30771da177e4SLinus Torvalds 30781da177e4SLinus Torvalds /* Release all mmaps. */ 30791da177e4SLinus Torvalds void exit_mmap(struct mm_struct *mm) 30801da177e4SLinus Torvalds { 3081d16dfc55SPeter Zijlstra struct mmu_gather tlb; 3082ba470de4SRik van Riel struct vm_area_struct *vma; 30831da177e4SLinus Torvalds unsigned long nr_accounted = 0; 3084763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 3085763ecb03SLiam R. Howlett int count = 0; 30861da177e4SLinus Torvalds 3087d6dd61c8SJeremy Fitzhardinge /* mm's last user has gone, and its about to be pulled down */ 3088cddb8a5cSAndrea Arcangeli mmu_notifier_release(mm); 3089d6dd61c8SJeremy Fitzhardinge 3090bf3980c8SSuren Baghdasaryan mmap_read_lock(mm); 30919480c53eSJeremy Fitzhardinge arch_exit_mmap(mm); 30929480c53eSJeremy Fitzhardinge 3093763ecb03SLiam R. Howlett vma = mas_find(&mas, ULONG_MAX); 309464591e86SSuren Baghdasaryan if (!vma) { 309564591e86SSuren Baghdasaryan /* Can happen if dup_mmap() received an OOM */ 3096bf3980c8SSuren Baghdasaryan mmap_read_unlock(mm); 30979480c53eSJeremy Fitzhardinge return; 309864591e86SSuren Baghdasaryan } 30999480c53eSJeremy Fitzhardinge 31001da177e4SLinus Torvalds lru_add_drain(); 31011da177e4SLinus Torvalds flush_cache_mm(mm); 3102d8b45053SWill Deacon tlb_gather_mmu_fullmm(&tlb, mm); 3103901608d9SOleg Nesterov /* update_hiwater_rss(mm) here? but nobody should be looking */ 3104763ecb03SLiam R. Howlett /* Use ULONG_MAX here to ensure all VMAs in the mm are unmapped */ 3105763ecb03SLiam R. Howlett unmap_vmas(&tlb, &mm->mm_mt, vma, 0, ULONG_MAX); 3106bf3980c8SSuren Baghdasaryan mmap_read_unlock(mm); 3107bf3980c8SSuren Baghdasaryan 3108bf3980c8SSuren Baghdasaryan /* 3109bf3980c8SSuren Baghdasaryan * Set MMF_OOM_SKIP to hide this task from the oom killer/reaper 3110b3541d91SSuren Baghdasaryan * because the memory has been already freed. 3111bf3980c8SSuren Baghdasaryan */ 3112bf3980c8SSuren Baghdasaryan set_bit(MMF_OOM_SKIP, &mm->flags); 3113bf3980c8SSuren Baghdasaryan mmap_write_lock(mm); 3114763ecb03SLiam R. Howlett free_pgtables(&tlb, &mm->mm_mt, vma, FIRST_USER_ADDRESS, 3115763ecb03SLiam R. Howlett USER_PGTABLES_CEILING); 3116ae8eba8bSWill Deacon tlb_finish_mmu(&tlb); 31171da177e4SLinus Torvalds 3118763ecb03SLiam R. Howlett /* 3119763ecb03SLiam R. Howlett * Walk the list again, actually closing and freeing it, with preemption 3120763ecb03SLiam R. Howlett * enabled, without holding any MM locks besides the unreachable 3121763ecb03SLiam R. Howlett * mmap_write_lock. 3122763ecb03SLiam R. Howlett */ 3123763ecb03SLiam R. Howlett do { 31244f74d2c8SLinus Torvalds if (vma->vm_flags & VM_ACCOUNT) 31254f74d2c8SLinus Torvalds nr_accounted += vma_pages(vma); 3126763ecb03SLiam R. Howlett remove_vma(vma); 3127763ecb03SLiam R. Howlett count++; 31280a3b3c25SPaul E. McKenney cond_resched(); 3129763ecb03SLiam R. Howlett } while ((vma = mas_find(&mas, ULONG_MAX)) != NULL); 3130763ecb03SLiam R. Howlett 3131763ecb03SLiam R. Howlett BUG_ON(count != mm->map_count); 3132d4af56c5SLiam R. Howlett 3133d4af56c5SLiam R. Howlett trace_exit_mmap(mm); 3134d4af56c5SLiam R. Howlett __mt_destroy(&mm->mm_mt); 313564591e86SSuren Baghdasaryan mmap_write_unlock(mm); 31364f74d2c8SLinus Torvalds vm_unacct_memory(nr_accounted); 31371da177e4SLinus Torvalds } 31381da177e4SLinus Torvalds 31391da177e4SLinus Torvalds /* Insert vm structure into process list sorted by address 31401da177e4SLinus Torvalds * and into the inode's i_mmap tree. If vm_file is non-NULL 3141c8c06efaSDavidlohr Bueso * then i_mmap_rwsem is taken here. 31421da177e4SLinus Torvalds */ 31431da177e4SLinus Torvalds int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) 31441da177e4SLinus Torvalds { 3145d4af56c5SLiam R. Howlett unsigned long charged = vma_pages(vma); 31461da177e4SLinus Torvalds 3147d4af56c5SLiam R. Howlett 3148d0601a50SLiam R. Howlett if (find_vma_intersection(mm, vma->vm_start, vma->vm_end)) 3149c9d13f5fSChen Gang return -ENOMEM; 3150d4af56c5SLiam R. Howlett 3151c9d13f5fSChen Gang if ((vma->vm_flags & VM_ACCOUNT) && 3152d4af56c5SLiam R. Howlett security_vm_enough_memory_mm(mm, charged)) 3153c9d13f5fSChen Gang return -ENOMEM; 3154c9d13f5fSChen Gang 31551da177e4SLinus Torvalds /* 31561da177e4SLinus Torvalds * The vm_pgoff of a purely anonymous vma should be irrelevant 31571da177e4SLinus Torvalds * until its first write fault, when page's anon_vma and index 31581da177e4SLinus Torvalds * are set. But now set the vm_pgoff it will almost certainly 31591da177e4SLinus Torvalds * end up with (unless mremap moves it elsewhere before that 31601da177e4SLinus Torvalds * first wfault), so /proc/pid/maps tells a consistent story. 31611da177e4SLinus Torvalds * 31621da177e4SLinus Torvalds * By setting it to reflect the virtual start address of the 31631da177e4SLinus Torvalds * vma, merges and splits can happen in a seamless way, just 31641da177e4SLinus Torvalds * using the existing file pgoff checks and manipulations. 31658332326eSLiao Pingfang * Similarly in do_mmap and in do_brk_flags. 31661da177e4SLinus Torvalds */ 31678a9cc3b5SOleg Nesterov if (vma_is_anonymous(vma)) { 31681da177e4SLinus Torvalds BUG_ON(vma->anon_vma); 31691da177e4SLinus Torvalds vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT; 31701da177e4SLinus Torvalds } 31712b144498SSrikar Dronamraju 3172763ecb03SLiam R. Howlett if (vma_link(mm, vma)) { 3173d4af56c5SLiam R. Howlett vm_unacct_memory(charged); 3174d4af56c5SLiam R. Howlett return -ENOMEM; 3175d4af56c5SLiam R. Howlett } 3176d4af56c5SLiam R. Howlett 31771da177e4SLinus Torvalds return 0; 31781da177e4SLinus Torvalds } 31791da177e4SLinus Torvalds 31801da177e4SLinus Torvalds /* 31811da177e4SLinus Torvalds * Copy the vma structure to a new location in the same mm, 31821da177e4SLinus Torvalds * prior to moving page table entries, to effect an mremap move. 31831da177e4SLinus Torvalds */ 31841da177e4SLinus Torvalds struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, 318538a76013SMichel Lespinasse unsigned long addr, unsigned long len, pgoff_t pgoff, 318638a76013SMichel Lespinasse bool *need_rmap_locks) 31871da177e4SLinus Torvalds { 31881da177e4SLinus Torvalds struct vm_area_struct *vma = *vmap; 31891da177e4SLinus Torvalds unsigned long vma_start = vma->vm_start; 31901da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 31911da177e4SLinus Torvalds struct vm_area_struct *new_vma, *prev; 3192948f017bSAndrea Arcangeli bool faulted_in_anon_vma = true; 31931da177e4SLinus Torvalds 3194d4af56c5SLiam R. Howlett validate_mm_mt(mm); 31951da177e4SLinus Torvalds /* 31961da177e4SLinus Torvalds * If anonymous vma has not yet been faulted, update new pgoff 31971da177e4SLinus Torvalds * to match new location, to increase its chance of merging. 31981da177e4SLinus Torvalds */ 3199ce75799bSOleg Nesterov if (unlikely(vma_is_anonymous(vma) && !vma->anon_vma)) { 32001da177e4SLinus Torvalds pgoff = addr >> PAGE_SHIFT; 3201948f017bSAndrea Arcangeli faulted_in_anon_vma = false; 3202948f017bSAndrea Arcangeli } 32031da177e4SLinus Torvalds 3204763ecb03SLiam R. Howlett new_vma = find_vma_prev(mm, addr, &prev); 3205763ecb03SLiam R. Howlett if (new_vma && new_vma->vm_start < addr + len) 32066597d783SHugh Dickins return NULL; /* should never get here */ 3207524e00b3SLiam R. Howlett 32081da177e4SLinus Torvalds new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags, 320919a809afSAndrea Arcangeli vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma), 32105c26f6acSSuren Baghdasaryan vma->vm_userfaultfd_ctx, anon_vma_name(vma)); 32111da177e4SLinus Torvalds if (new_vma) { 32121da177e4SLinus Torvalds /* 32131da177e4SLinus Torvalds * Source vma may have been merged into new_vma 32141da177e4SLinus Torvalds */ 3215948f017bSAndrea Arcangeli if (unlikely(vma_start >= new_vma->vm_start && 3216948f017bSAndrea Arcangeli vma_start < new_vma->vm_end)) { 3217948f017bSAndrea Arcangeli /* 3218948f017bSAndrea Arcangeli * The only way we can get a vma_merge with 3219948f017bSAndrea Arcangeli * self during an mremap is if the vma hasn't 3220948f017bSAndrea Arcangeli * been faulted in yet and we were allowed to 3221948f017bSAndrea Arcangeli * reset the dst vma->vm_pgoff to the 3222948f017bSAndrea Arcangeli * destination address of the mremap to allow 3223948f017bSAndrea Arcangeli * the merge to happen. mremap must change the 3224948f017bSAndrea Arcangeli * vm_pgoff linearity between src and dst vmas 3225948f017bSAndrea Arcangeli * (in turn preventing a vma_merge) to be 3226948f017bSAndrea Arcangeli * safe. It is only safe to keep the vm_pgoff 3227948f017bSAndrea Arcangeli * linear if there are no pages mapped yet. 3228948f017bSAndrea Arcangeli */ 322981d1b09cSSasha Levin VM_BUG_ON_VMA(faulted_in_anon_vma, new_vma); 323038a76013SMichel Lespinasse *vmap = vma = new_vma; 3231108d6642SMichel Lespinasse } 323238a76013SMichel Lespinasse *need_rmap_locks = (new_vma->vm_pgoff <= vma->vm_pgoff); 32331da177e4SLinus Torvalds } else { 32343928d4f5SLinus Torvalds new_vma = vm_area_dup(vma); 3235e3975891SChen Gang if (!new_vma) 3236e3975891SChen Gang goto out; 32371da177e4SLinus Torvalds new_vma->vm_start = addr; 32381da177e4SLinus Torvalds new_vma->vm_end = addr + len; 32391da177e4SLinus Torvalds new_vma->vm_pgoff = pgoff; 3240ef0855d3SOleg Nesterov if (vma_dup_policy(vma, new_vma)) 3241523d4e20SMichel Lespinasse goto out_free_vma; 3242523d4e20SMichel Lespinasse if (anon_vma_clone(new_vma, vma)) 3243523d4e20SMichel Lespinasse goto out_free_mempol; 3244e9714acfSKonstantin Khlebnikov if (new_vma->vm_file) 32451da177e4SLinus Torvalds get_file(new_vma->vm_file); 32461da177e4SLinus Torvalds if (new_vma->vm_ops && new_vma->vm_ops->open) 32471da177e4SLinus Torvalds new_vma->vm_ops->open(new_vma); 3248763ecb03SLiam R. Howlett if (vma_link(mm, new_vma)) 3249524e00b3SLiam R. Howlett goto out_vma_link; 325038a76013SMichel Lespinasse *need_rmap_locks = false; 32511da177e4SLinus Torvalds } 3252d4af56c5SLiam R. Howlett validate_mm_mt(mm); 32531da177e4SLinus Torvalds return new_vma; 32545beb4930SRik van Riel 3255524e00b3SLiam R. Howlett out_vma_link: 3256524e00b3SLiam R. Howlett if (new_vma->vm_ops && new_vma->vm_ops->close) 3257524e00b3SLiam R. Howlett new_vma->vm_ops->close(new_vma); 325892b73996SLiam Howlett 325992b73996SLiam Howlett if (new_vma->vm_file) 326092b73996SLiam Howlett fput(new_vma->vm_file); 326192b73996SLiam Howlett 326292b73996SLiam Howlett unlink_anon_vmas(new_vma); 32635beb4930SRik van Riel out_free_mempol: 3264ef0855d3SOleg Nesterov mpol_put(vma_policy(new_vma)); 32655beb4930SRik van Riel out_free_vma: 32663928d4f5SLinus Torvalds vm_area_free(new_vma); 3267e3975891SChen Gang out: 3268d4af56c5SLiam R. Howlett validate_mm_mt(mm); 32695beb4930SRik van Riel return NULL; 32701da177e4SLinus Torvalds } 3271119f657cSakpm@osdl.org 3272119f657cSakpm@osdl.org /* 3273119f657cSakpm@osdl.org * Return true if the calling process may expand its vm space by the passed 3274119f657cSakpm@osdl.org * number of pages 3275119f657cSakpm@osdl.org */ 327684638335SKonstantin Khlebnikov bool may_expand_vm(struct mm_struct *mm, vm_flags_t flags, unsigned long npages) 3277119f657cSakpm@osdl.org { 327884638335SKonstantin Khlebnikov if (mm->total_vm + npages > rlimit(RLIMIT_AS) >> PAGE_SHIFT) 327984638335SKonstantin Khlebnikov return false; 3280119f657cSakpm@osdl.org 3281d977d56cSKonstantin Khlebnikov if (is_data_mapping(flags) && 3282d977d56cSKonstantin Khlebnikov mm->data_vm + npages > rlimit(RLIMIT_DATA) >> PAGE_SHIFT) { 3283f4fcd558SKonstantin Khlebnikov /* Workaround for Valgrind */ 3284f4fcd558SKonstantin Khlebnikov if (rlimit(RLIMIT_DATA) == 0 && 3285f4fcd558SKonstantin Khlebnikov mm->data_vm + npages <= rlimit_max(RLIMIT_DATA) >> PAGE_SHIFT) 3286f4fcd558SKonstantin Khlebnikov return true; 328757a7702bSDavid Woodhouse 328857a7702bSDavid Woodhouse pr_warn_once("%s (%d): VmData %lu exceed data ulimit %lu. Update limits%s.\n", 3289d977d56cSKonstantin Khlebnikov current->comm, current->pid, 3290d977d56cSKonstantin Khlebnikov (mm->data_vm + npages) << PAGE_SHIFT, 329157a7702bSDavid Woodhouse rlimit(RLIMIT_DATA), 329257a7702bSDavid Woodhouse ignore_rlimit_data ? "" : " or use boot option ignore_rlimit_data"); 329357a7702bSDavid Woodhouse 329457a7702bSDavid Woodhouse if (!ignore_rlimit_data) 3295d977d56cSKonstantin Khlebnikov return false; 3296d977d56cSKonstantin Khlebnikov } 3297119f657cSakpm@osdl.org 329884638335SKonstantin Khlebnikov return true; 329984638335SKonstantin Khlebnikov } 330084638335SKonstantin Khlebnikov 330184638335SKonstantin Khlebnikov void vm_stat_account(struct mm_struct *mm, vm_flags_t flags, long npages) 330284638335SKonstantin Khlebnikov { 33037866076bSPeng Liu WRITE_ONCE(mm->total_vm, READ_ONCE(mm->total_vm)+npages); 330484638335SKonstantin Khlebnikov 3305d977d56cSKonstantin Khlebnikov if (is_exec_mapping(flags)) 330684638335SKonstantin Khlebnikov mm->exec_vm += npages; 3307d977d56cSKonstantin Khlebnikov else if (is_stack_mapping(flags)) 330884638335SKonstantin Khlebnikov mm->stack_vm += npages; 3309d977d56cSKonstantin Khlebnikov else if (is_data_mapping(flags)) 331084638335SKonstantin Khlebnikov mm->data_vm += npages; 3311119f657cSakpm@osdl.org } 3312fa5dc22fSRoland McGrath 3313b3ec9f33SSouptick Joarder static vm_fault_t special_mapping_fault(struct vm_fault *vmf); 3314a62c34bdSAndy Lutomirski 3315a62c34bdSAndy Lutomirski /* 3316a62c34bdSAndy Lutomirski * Having a close hook prevents vma merging regardless of flags. 3317a62c34bdSAndy Lutomirski */ 3318a62c34bdSAndy Lutomirski static void special_mapping_close(struct vm_area_struct *vma) 3319a62c34bdSAndy Lutomirski { 3320a62c34bdSAndy Lutomirski } 3321a62c34bdSAndy Lutomirski 3322a62c34bdSAndy Lutomirski static const char *special_mapping_name(struct vm_area_struct *vma) 3323a62c34bdSAndy Lutomirski { 3324a62c34bdSAndy Lutomirski return ((struct vm_special_mapping *)vma->vm_private_data)->name; 3325a62c34bdSAndy Lutomirski } 3326a62c34bdSAndy Lutomirski 332714d07113SBrian Geffon static int special_mapping_mremap(struct vm_area_struct *new_vma) 3328b059a453SDmitry Safonov { 3329b059a453SDmitry Safonov struct vm_special_mapping *sm = new_vma->vm_private_data; 3330b059a453SDmitry Safonov 3331280e87e9SDmitry Safonov if (WARN_ON_ONCE(current->mm != new_vma->vm_mm)) 3332280e87e9SDmitry Safonov return -EFAULT; 3333280e87e9SDmitry Safonov 3334b059a453SDmitry Safonov if (sm->mremap) 3335b059a453SDmitry Safonov return sm->mremap(sm, new_vma); 3336280e87e9SDmitry Safonov 3337b059a453SDmitry Safonov return 0; 3338b059a453SDmitry Safonov } 3339b059a453SDmitry Safonov 3340871402e0SDmitry Safonov static int special_mapping_split(struct vm_area_struct *vma, unsigned long addr) 3341871402e0SDmitry Safonov { 3342871402e0SDmitry Safonov /* 3343871402e0SDmitry Safonov * Forbid splitting special mappings - kernel has expectations over 3344871402e0SDmitry Safonov * the number of pages in mapping. Together with VM_DONTEXPAND 3345871402e0SDmitry Safonov * the size of vma should stay the same over the special mapping's 3346871402e0SDmitry Safonov * lifetime. 3347871402e0SDmitry Safonov */ 3348871402e0SDmitry Safonov return -EINVAL; 3349871402e0SDmitry Safonov } 3350871402e0SDmitry Safonov 3351a62c34bdSAndy Lutomirski static const struct vm_operations_struct special_mapping_vmops = { 3352a62c34bdSAndy Lutomirski .close = special_mapping_close, 3353a62c34bdSAndy Lutomirski .fault = special_mapping_fault, 3354b059a453SDmitry Safonov .mremap = special_mapping_mremap, 3355a62c34bdSAndy Lutomirski .name = special_mapping_name, 3356af34ebebSDmitry Safonov /* vDSO code relies that VVAR can't be accessed remotely */ 3357af34ebebSDmitry Safonov .access = NULL, 3358871402e0SDmitry Safonov .may_split = special_mapping_split, 3359a62c34bdSAndy Lutomirski }; 3360a62c34bdSAndy Lutomirski 3361a62c34bdSAndy Lutomirski static const struct vm_operations_struct legacy_special_mapping_vmops = { 3362a62c34bdSAndy Lutomirski .close = special_mapping_close, 3363a62c34bdSAndy Lutomirski .fault = special_mapping_fault, 3364a62c34bdSAndy Lutomirski }; 3365fa5dc22fSRoland McGrath 3366b3ec9f33SSouptick Joarder static vm_fault_t special_mapping_fault(struct vm_fault *vmf) 3367fa5dc22fSRoland McGrath { 336811bac800SDave Jiang struct vm_area_struct *vma = vmf->vma; 3369b1d0e4f5SNick Piggin pgoff_t pgoff; 3370fa5dc22fSRoland McGrath struct page **pages; 3371fa5dc22fSRoland McGrath 3372f872f540SAndy Lutomirski if (vma->vm_ops == &legacy_special_mapping_vmops) { 3373a62c34bdSAndy Lutomirski pages = vma->vm_private_data; 3374f872f540SAndy Lutomirski } else { 3375f872f540SAndy Lutomirski struct vm_special_mapping *sm = vma->vm_private_data; 3376f872f540SAndy Lutomirski 3377f872f540SAndy Lutomirski if (sm->fault) 337811bac800SDave Jiang return sm->fault(sm, vmf->vma, vmf); 3379f872f540SAndy Lutomirski 3380f872f540SAndy Lutomirski pages = sm->pages; 3381f872f540SAndy Lutomirski } 3382a62c34bdSAndy Lutomirski 33838a9cc3b5SOleg Nesterov for (pgoff = vmf->pgoff; pgoff && *pages; ++pages) 3384b1d0e4f5SNick Piggin pgoff--; 3385fa5dc22fSRoland McGrath 3386fa5dc22fSRoland McGrath if (*pages) { 3387fa5dc22fSRoland McGrath struct page *page = *pages; 3388fa5dc22fSRoland McGrath get_page(page); 3389b1d0e4f5SNick Piggin vmf->page = page; 3390b1d0e4f5SNick Piggin return 0; 3391fa5dc22fSRoland McGrath } 3392fa5dc22fSRoland McGrath 3393b1d0e4f5SNick Piggin return VM_FAULT_SIGBUS; 3394fa5dc22fSRoland McGrath } 3395fa5dc22fSRoland McGrath 3396a62c34bdSAndy Lutomirski static struct vm_area_struct *__install_special_mapping( 3397a62c34bdSAndy Lutomirski struct mm_struct *mm, 3398fa5dc22fSRoland McGrath unsigned long addr, unsigned long len, 339927f28b97SChen Gang unsigned long vm_flags, void *priv, 340027f28b97SChen Gang const struct vm_operations_struct *ops) 3401fa5dc22fSRoland McGrath { 3402462e635eSTavis Ormandy int ret; 3403fa5dc22fSRoland McGrath struct vm_area_struct *vma; 3404fa5dc22fSRoland McGrath 3405d4af56c5SLiam R. Howlett validate_mm_mt(mm); 3406490fc053SLinus Torvalds vma = vm_area_alloc(mm); 3407fa5dc22fSRoland McGrath if (unlikely(vma == NULL)) 34083935ed6aSStefani Seibold return ERR_PTR(-ENOMEM); 3409fa5dc22fSRoland McGrath 3410fa5dc22fSRoland McGrath vma->vm_start = addr; 3411fa5dc22fSRoland McGrath vma->vm_end = addr + len; 3412fa5dc22fSRoland McGrath 3413d9104d1cSCyrill Gorcunov vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND | VM_SOFTDIRTY; 34141fc09228SHugh Dickins vma->vm_flags &= VM_LOCKED_CLEAR_MASK; 34153ed75eb8SColy Li vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); 3416fa5dc22fSRoland McGrath 3417a62c34bdSAndy Lutomirski vma->vm_ops = ops; 3418a62c34bdSAndy Lutomirski vma->vm_private_data = priv; 3419fa5dc22fSRoland McGrath 3420462e635eSTavis Ormandy ret = insert_vm_struct(mm, vma); 3421462e635eSTavis Ormandy if (ret) 3422462e635eSTavis Ormandy goto out; 3423fa5dc22fSRoland McGrath 342484638335SKonstantin Khlebnikov vm_stat_account(mm, vma->vm_flags, len >> PAGE_SHIFT); 3425fa5dc22fSRoland McGrath 3426cdd6c482SIngo Molnar perf_event_mmap(vma); 3427089dd79dSPeter Zijlstra 3428d4af56c5SLiam R. Howlett validate_mm_mt(mm); 34293935ed6aSStefani Seibold return vma; 3430462e635eSTavis Ormandy 3431462e635eSTavis Ormandy out: 34323928d4f5SLinus Torvalds vm_area_free(vma); 3433d4af56c5SLiam R. Howlett validate_mm_mt(mm); 34343935ed6aSStefani Seibold return ERR_PTR(ret); 34353935ed6aSStefani Seibold } 34363935ed6aSStefani Seibold 34372eefd878SDmitry Safonov bool vma_is_special_mapping(const struct vm_area_struct *vma, 34382eefd878SDmitry Safonov const struct vm_special_mapping *sm) 34392eefd878SDmitry Safonov { 34402eefd878SDmitry Safonov return vma->vm_private_data == sm && 34412eefd878SDmitry Safonov (vma->vm_ops == &special_mapping_vmops || 34422eefd878SDmitry Safonov vma->vm_ops == &legacy_special_mapping_vmops); 34432eefd878SDmitry Safonov } 34442eefd878SDmitry Safonov 3445a62c34bdSAndy Lutomirski /* 3446c1e8d7c6SMichel Lespinasse * Called with mm->mmap_lock held for writing. 3447a62c34bdSAndy Lutomirski * Insert a new vma covering the given region, with the given flags. 3448a62c34bdSAndy Lutomirski * Its pages are supplied by the given array of struct page *. 3449a62c34bdSAndy Lutomirski * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated. 3450a62c34bdSAndy Lutomirski * The region past the last page supplied will always produce SIGBUS. 3451a62c34bdSAndy Lutomirski * The array pointer and the pages it points to are assumed to stay alive 3452a62c34bdSAndy Lutomirski * for as long as this mapping might exist. 3453a62c34bdSAndy Lutomirski */ 3454a62c34bdSAndy Lutomirski struct vm_area_struct *_install_special_mapping( 3455a62c34bdSAndy Lutomirski struct mm_struct *mm, 3456a62c34bdSAndy Lutomirski unsigned long addr, unsigned long len, 3457a62c34bdSAndy Lutomirski unsigned long vm_flags, const struct vm_special_mapping *spec) 3458a62c34bdSAndy Lutomirski { 345927f28b97SChen Gang return __install_special_mapping(mm, addr, len, vm_flags, (void *)spec, 346027f28b97SChen Gang &special_mapping_vmops); 3461a62c34bdSAndy Lutomirski } 3462a62c34bdSAndy Lutomirski 34633935ed6aSStefani Seibold int install_special_mapping(struct mm_struct *mm, 34643935ed6aSStefani Seibold unsigned long addr, unsigned long len, 34653935ed6aSStefani Seibold unsigned long vm_flags, struct page **pages) 34663935ed6aSStefani Seibold { 3467a62c34bdSAndy Lutomirski struct vm_area_struct *vma = __install_special_mapping( 346827f28b97SChen Gang mm, addr, len, vm_flags, (void *)pages, 346927f28b97SChen Gang &legacy_special_mapping_vmops); 34703935ed6aSStefani Seibold 347114bd5b45SDuan Jiong return PTR_ERR_OR_ZERO(vma); 3472fa5dc22fSRoland McGrath } 34737906d00cSAndrea Arcangeli 34747906d00cSAndrea Arcangeli static DEFINE_MUTEX(mm_all_locks_mutex); 34757906d00cSAndrea Arcangeli 3476454ed842SPeter Zijlstra static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma) 34777906d00cSAndrea Arcangeli { 3478f808c13fSDavidlohr Bueso if (!test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_root.rb_node)) { 34797906d00cSAndrea Arcangeli /* 34807906d00cSAndrea Arcangeli * The LSB of head.next can't change from under us 34817906d00cSAndrea Arcangeli * because we hold the mm_all_locks_mutex. 34827906d00cSAndrea Arcangeli */ 3483da1c55f1SMichel Lespinasse down_write_nest_lock(&anon_vma->root->rwsem, &mm->mmap_lock); 34847906d00cSAndrea Arcangeli /* 34857906d00cSAndrea Arcangeli * We can safely modify head.next after taking the 34865a505085SIngo Molnar * anon_vma->root->rwsem. If some other vma in this mm shares 34877906d00cSAndrea Arcangeli * the same anon_vma we won't take it again. 34887906d00cSAndrea Arcangeli * 34897906d00cSAndrea Arcangeli * No need of atomic instructions here, head.next 34907906d00cSAndrea Arcangeli * can't change from under us thanks to the 34915a505085SIngo Molnar * anon_vma->root->rwsem. 34927906d00cSAndrea Arcangeli */ 34937906d00cSAndrea Arcangeli if (__test_and_set_bit(0, (unsigned long *) 3494f808c13fSDavidlohr Bueso &anon_vma->root->rb_root.rb_root.rb_node)) 34957906d00cSAndrea Arcangeli BUG(); 34967906d00cSAndrea Arcangeli } 34977906d00cSAndrea Arcangeli } 34987906d00cSAndrea Arcangeli 3499454ed842SPeter Zijlstra static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping) 35007906d00cSAndrea Arcangeli { 35017906d00cSAndrea Arcangeli if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { 35027906d00cSAndrea Arcangeli /* 35037906d00cSAndrea Arcangeli * AS_MM_ALL_LOCKS can't change from under us because 35047906d00cSAndrea Arcangeli * we hold the mm_all_locks_mutex. 35057906d00cSAndrea Arcangeli * 35067906d00cSAndrea Arcangeli * Operations on ->flags have to be atomic because 35077906d00cSAndrea Arcangeli * even if AS_MM_ALL_LOCKS is stable thanks to the 35087906d00cSAndrea Arcangeli * mm_all_locks_mutex, there may be other cpus 35097906d00cSAndrea Arcangeli * changing other bitflags in parallel to us. 35107906d00cSAndrea Arcangeli */ 35117906d00cSAndrea Arcangeli if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags)) 35127906d00cSAndrea Arcangeli BUG(); 3513da1c55f1SMichel Lespinasse down_write_nest_lock(&mapping->i_mmap_rwsem, &mm->mmap_lock); 35147906d00cSAndrea Arcangeli } 35157906d00cSAndrea Arcangeli } 35167906d00cSAndrea Arcangeli 35177906d00cSAndrea Arcangeli /* 35187906d00cSAndrea Arcangeli * This operation locks against the VM for all pte/vma/mm related 35197906d00cSAndrea Arcangeli * operations that could ever happen on a certain mm. This includes 35207906d00cSAndrea Arcangeli * vmtruncate, try_to_unmap, and all page faults. 35217906d00cSAndrea Arcangeli * 3522c1e8d7c6SMichel Lespinasse * The caller must take the mmap_lock in write mode before calling 35237906d00cSAndrea Arcangeli * mm_take_all_locks(). The caller isn't allowed to release the 3524c1e8d7c6SMichel Lespinasse * mmap_lock until mm_drop_all_locks() returns. 35257906d00cSAndrea Arcangeli * 3526c1e8d7c6SMichel Lespinasse * mmap_lock in write mode is required in order to block all operations 35277906d00cSAndrea Arcangeli * that could modify pagetables and free pages without need of 352827ba0644SKirill A. Shutemov * altering the vma layout. It's also needed in write mode to avoid new 35297906d00cSAndrea Arcangeli * anon_vmas to be associated with existing vmas. 35307906d00cSAndrea Arcangeli * 35317906d00cSAndrea Arcangeli * A single task can't take more than one mm_take_all_locks() in a row 35327906d00cSAndrea Arcangeli * or it would deadlock. 35337906d00cSAndrea Arcangeli * 3534bf181b9fSMichel Lespinasse * The LSB in anon_vma->rb_root.rb_node and the AS_MM_ALL_LOCKS bitflag in 35357906d00cSAndrea Arcangeli * mapping->flags avoid to take the same lock twice, if more than one 35367906d00cSAndrea Arcangeli * vma in this mm is backed by the same anon_vma or address_space. 35377906d00cSAndrea Arcangeli * 353888f306b6SKirill A. Shutemov * We take locks in following order, accordingly to comment at beginning 353988f306b6SKirill A. Shutemov * of mm/rmap.c: 354088f306b6SKirill A. Shutemov * - all hugetlbfs_i_mmap_rwsem_key locks (aka mapping->i_mmap_rwsem for 354188f306b6SKirill A. Shutemov * hugetlb mapping); 354288f306b6SKirill A. Shutemov * - all i_mmap_rwsem locks; 354388f306b6SKirill A. Shutemov * - all anon_vma->rwseml 354488f306b6SKirill A. Shutemov * 354588f306b6SKirill A. Shutemov * We can take all locks within these types randomly because the VM code 354688f306b6SKirill A. Shutemov * doesn't nest them and we protected from parallel mm_take_all_locks() by 354788f306b6SKirill A. Shutemov * mm_all_locks_mutex. 35487906d00cSAndrea Arcangeli * 35497906d00cSAndrea Arcangeli * mm_take_all_locks() and mm_drop_all_locks are expensive operations 35507906d00cSAndrea Arcangeli * that may have to take thousand of locks. 35517906d00cSAndrea Arcangeli * 35527906d00cSAndrea Arcangeli * mm_take_all_locks() can fail if it's interrupted by signals. 35537906d00cSAndrea Arcangeli */ 35547906d00cSAndrea Arcangeli int mm_take_all_locks(struct mm_struct *mm) 35557906d00cSAndrea Arcangeli { 35567906d00cSAndrea Arcangeli struct vm_area_struct *vma; 35575beb4930SRik van Riel struct anon_vma_chain *avc; 3558763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 35597906d00cSAndrea Arcangeli 3560325bca1fSRolf Eike Beer mmap_assert_write_locked(mm); 35617906d00cSAndrea Arcangeli 35627906d00cSAndrea Arcangeli mutex_lock(&mm_all_locks_mutex); 35637906d00cSAndrea Arcangeli 3564763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 35657906d00cSAndrea Arcangeli if (signal_pending(current)) 35667906d00cSAndrea Arcangeli goto out_unlock; 356788f306b6SKirill A. Shutemov if (vma->vm_file && vma->vm_file->f_mapping && 356888f306b6SKirill A. Shutemov is_vm_hugetlb_page(vma)) 356988f306b6SKirill A. Shutemov vm_lock_mapping(mm, vma->vm_file->f_mapping); 357088f306b6SKirill A. Shutemov } 357188f306b6SKirill A. Shutemov 3572763ecb03SLiam R. Howlett mas_set(&mas, 0); 3573763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 357488f306b6SKirill A. Shutemov if (signal_pending(current)) 357588f306b6SKirill A. Shutemov goto out_unlock; 357688f306b6SKirill A. Shutemov if (vma->vm_file && vma->vm_file->f_mapping && 357788f306b6SKirill A. Shutemov !is_vm_hugetlb_page(vma)) 3578454ed842SPeter Zijlstra vm_lock_mapping(mm, vma->vm_file->f_mapping); 35797906d00cSAndrea Arcangeli } 35807cd5a02fSPeter Zijlstra 3581763ecb03SLiam R. Howlett mas_set(&mas, 0); 3582763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 35837cd5a02fSPeter Zijlstra if (signal_pending(current)) 35847cd5a02fSPeter Zijlstra goto out_unlock; 35857cd5a02fSPeter Zijlstra if (vma->anon_vma) 35865beb4930SRik van Riel list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 35875beb4930SRik van Riel vm_lock_anon_vma(mm, avc->anon_vma); 35887cd5a02fSPeter Zijlstra } 35897cd5a02fSPeter Zijlstra 3590584cff54SKautuk Consul return 0; 35917906d00cSAndrea Arcangeli 35927906d00cSAndrea Arcangeli out_unlock: 35937906d00cSAndrea Arcangeli mm_drop_all_locks(mm); 3594584cff54SKautuk Consul return -EINTR; 35957906d00cSAndrea Arcangeli } 35967906d00cSAndrea Arcangeli 35977906d00cSAndrea Arcangeli static void vm_unlock_anon_vma(struct anon_vma *anon_vma) 35987906d00cSAndrea Arcangeli { 3599f808c13fSDavidlohr Bueso if (test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_root.rb_node)) { 36007906d00cSAndrea Arcangeli /* 36017906d00cSAndrea Arcangeli * The LSB of head.next can't change to 0 from under 36027906d00cSAndrea Arcangeli * us because we hold the mm_all_locks_mutex. 36037906d00cSAndrea Arcangeli * 36047906d00cSAndrea Arcangeli * We must however clear the bitflag before unlocking 3605bf181b9fSMichel Lespinasse * the vma so the users using the anon_vma->rb_root will 36067906d00cSAndrea Arcangeli * never see our bitflag. 36077906d00cSAndrea Arcangeli * 36087906d00cSAndrea Arcangeli * No need of atomic instructions here, head.next 36097906d00cSAndrea Arcangeli * can't change from under us until we release the 36105a505085SIngo Molnar * anon_vma->root->rwsem. 36117906d00cSAndrea Arcangeli */ 36127906d00cSAndrea Arcangeli if (!__test_and_clear_bit(0, (unsigned long *) 3613f808c13fSDavidlohr Bueso &anon_vma->root->rb_root.rb_root.rb_node)) 36147906d00cSAndrea Arcangeli BUG(); 361508b52706SKonstantin Khlebnikov anon_vma_unlock_write(anon_vma); 36167906d00cSAndrea Arcangeli } 36177906d00cSAndrea Arcangeli } 36187906d00cSAndrea Arcangeli 36197906d00cSAndrea Arcangeli static void vm_unlock_mapping(struct address_space *mapping) 36207906d00cSAndrea Arcangeli { 36217906d00cSAndrea Arcangeli if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { 36227906d00cSAndrea Arcangeli /* 36237906d00cSAndrea Arcangeli * AS_MM_ALL_LOCKS can't change to 0 from under us 36247906d00cSAndrea Arcangeli * because we hold the mm_all_locks_mutex. 36257906d00cSAndrea Arcangeli */ 362683cde9e8SDavidlohr Bueso i_mmap_unlock_write(mapping); 36277906d00cSAndrea Arcangeli if (!test_and_clear_bit(AS_MM_ALL_LOCKS, 36287906d00cSAndrea Arcangeli &mapping->flags)) 36297906d00cSAndrea Arcangeli BUG(); 36307906d00cSAndrea Arcangeli } 36317906d00cSAndrea Arcangeli } 36327906d00cSAndrea Arcangeli 36337906d00cSAndrea Arcangeli /* 3634c1e8d7c6SMichel Lespinasse * The mmap_lock cannot be released by the caller until 36357906d00cSAndrea Arcangeli * mm_drop_all_locks() returns. 36367906d00cSAndrea Arcangeli */ 36377906d00cSAndrea Arcangeli void mm_drop_all_locks(struct mm_struct *mm) 36387906d00cSAndrea Arcangeli { 36397906d00cSAndrea Arcangeli struct vm_area_struct *vma; 36405beb4930SRik van Riel struct anon_vma_chain *avc; 3641763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 36427906d00cSAndrea Arcangeli 3643325bca1fSRolf Eike Beer mmap_assert_write_locked(mm); 36447906d00cSAndrea Arcangeli BUG_ON(!mutex_is_locked(&mm_all_locks_mutex)); 36457906d00cSAndrea Arcangeli 3646763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 36477906d00cSAndrea Arcangeli if (vma->anon_vma) 36485beb4930SRik van Riel list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 36495beb4930SRik van Riel vm_unlock_anon_vma(avc->anon_vma); 36507906d00cSAndrea Arcangeli if (vma->vm_file && vma->vm_file->f_mapping) 36517906d00cSAndrea Arcangeli vm_unlock_mapping(vma->vm_file->f_mapping); 36527906d00cSAndrea Arcangeli } 36537906d00cSAndrea Arcangeli 36547906d00cSAndrea Arcangeli mutex_unlock(&mm_all_locks_mutex); 36557906d00cSAndrea Arcangeli } 36568feae131SDavid Howells 36578feae131SDavid Howells /* 36583edf41d8Sseokhoon.yoon * initialise the percpu counter for VM 36598feae131SDavid Howells */ 36608feae131SDavid Howells void __init mmap_init(void) 36618feae131SDavid Howells { 366200a62ce9SKOSAKI Motohiro int ret; 366300a62ce9SKOSAKI Motohiro 3664908c7f19STejun Heo ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL); 366500a62ce9SKOSAKI Motohiro VM_BUG_ON(ret); 36668feae131SDavid Howells } 3667c9b1d098SAndrew Shewmaker 3668c9b1d098SAndrew Shewmaker /* 3669c9b1d098SAndrew Shewmaker * Initialise sysctl_user_reserve_kbytes. 3670c9b1d098SAndrew Shewmaker * 3671c9b1d098SAndrew Shewmaker * This is intended to prevent a user from starting a single memory hogging 3672c9b1d098SAndrew Shewmaker * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER 3673c9b1d098SAndrew Shewmaker * mode. 3674c9b1d098SAndrew Shewmaker * 3675c9b1d098SAndrew Shewmaker * The default value is min(3% of free memory, 128MB) 3676c9b1d098SAndrew Shewmaker * 128MB is enough to recover with sshd/login, bash, and top/kill. 3677c9b1d098SAndrew Shewmaker */ 36781640879aSAndrew Shewmaker static int init_user_reserve(void) 3679c9b1d098SAndrew Shewmaker { 3680c9b1d098SAndrew Shewmaker unsigned long free_kbytes; 3681c9b1d098SAndrew Shewmaker 3682c41f012aSMichal Hocko free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); 3683c9b1d098SAndrew Shewmaker 3684c9b1d098SAndrew Shewmaker sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17); 3685c9b1d098SAndrew Shewmaker return 0; 3686c9b1d098SAndrew Shewmaker } 3687a64fb3cdSPaul Gortmaker subsys_initcall(init_user_reserve); 36884eeab4f5SAndrew Shewmaker 36894eeab4f5SAndrew Shewmaker /* 36904eeab4f5SAndrew Shewmaker * Initialise sysctl_admin_reserve_kbytes. 36914eeab4f5SAndrew Shewmaker * 36924eeab4f5SAndrew Shewmaker * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin 36934eeab4f5SAndrew Shewmaker * to log in and kill a memory hogging process. 36944eeab4f5SAndrew Shewmaker * 36954eeab4f5SAndrew Shewmaker * Systems with more than 256MB will reserve 8MB, enough to recover 36964eeab4f5SAndrew Shewmaker * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will 36974eeab4f5SAndrew Shewmaker * only reserve 3% of free pages by default. 36984eeab4f5SAndrew Shewmaker */ 36991640879aSAndrew Shewmaker static int init_admin_reserve(void) 37004eeab4f5SAndrew Shewmaker { 37014eeab4f5SAndrew Shewmaker unsigned long free_kbytes; 37024eeab4f5SAndrew Shewmaker 3703c41f012aSMichal Hocko free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); 37044eeab4f5SAndrew Shewmaker 37054eeab4f5SAndrew Shewmaker sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13); 37064eeab4f5SAndrew Shewmaker return 0; 37074eeab4f5SAndrew Shewmaker } 3708a64fb3cdSPaul Gortmaker subsys_initcall(init_admin_reserve); 37091640879aSAndrew Shewmaker 37101640879aSAndrew Shewmaker /* 37111640879aSAndrew Shewmaker * Reinititalise user and admin reserves if memory is added or removed. 37121640879aSAndrew Shewmaker * 37131640879aSAndrew Shewmaker * The default user reserve max is 128MB, and the default max for the 37141640879aSAndrew Shewmaker * admin reserve is 8MB. These are usually, but not always, enough to 37151640879aSAndrew Shewmaker * enable recovery from a memory hogging process using login/sshd, a shell, 37161640879aSAndrew Shewmaker * and tools like top. It may make sense to increase or even disable the 37171640879aSAndrew Shewmaker * reserve depending on the existence of swap or variations in the recovery 37181640879aSAndrew Shewmaker * tools. So, the admin may have changed them. 37191640879aSAndrew Shewmaker * 37201640879aSAndrew Shewmaker * If memory is added and the reserves have been eliminated or increased above 37211640879aSAndrew Shewmaker * the default max, then we'll trust the admin. 37221640879aSAndrew Shewmaker * 37231640879aSAndrew Shewmaker * If memory is removed and there isn't enough free memory, then we 37241640879aSAndrew Shewmaker * need to reset the reserves. 37251640879aSAndrew Shewmaker * 37261640879aSAndrew Shewmaker * Otherwise keep the reserve set by the admin. 37271640879aSAndrew Shewmaker */ 37281640879aSAndrew Shewmaker static int reserve_mem_notifier(struct notifier_block *nb, 37291640879aSAndrew Shewmaker unsigned long action, void *data) 37301640879aSAndrew Shewmaker { 37311640879aSAndrew Shewmaker unsigned long tmp, free_kbytes; 37321640879aSAndrew Shewmaker 37331640879aSAndrew Shewmaker switch (action) { 37341640879aSAndrew Shewmaker case MEM_ONLINE: 37351640879aSAndrew Shewmaker /* Default max is 128MB. Leave alone if modified by operator. */ 37361640879aSAndrew Shewmaker tmp = sysctl_user_reserve_kbytes; 37371640879aSAndrew Shewmaker if (0 < tmp && tmp < (1UL << 17)) 37381640879aSAndrew Shewmaker init_user_reserve(); 37391640879aSAndrew Shewmaker 37401640879aSAndrew Shewmaker /* Default max is 8MB. Leave alone if modified by operator. */ 37411640879aSAndrew Shewmaker tmp = sysctl_admin_reserve_kbytes; 37421640879aSAndrew Shewmaker if (0 < tmp && tmp < (1UL << 13)) 37431640879aSAndrew Shewmaker init_admin_reserve(); 37441640879aSAndrew Shewmaker 37451640879aSAndrew Shewmaker break; 37461640879aSAndrew Shewmaker case MEM_OFFLINE: 3747c41f012aSMichal Hocko free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); 37481640879aSAndrew Shewmaker 37491640879aSAndrew Shewmaker if (sysctl_user_reserve_kbytes > free_kbytes) { 37501640879aSAndrew Shewmaker init_user_reserve(); 37511640879aSAndrew Shewmaker pr_info("vm.user_reserve_kbytes reset to %lu\n", 37521640879aSAndrew Shewmaker sysctl_user_reserve_kbytes); 37531640879aSAndrew Shewmaker } 37541640879aSAndrew Shewmaker 37551640879aSAndrew Shewmaker if (sysctl_admin_reserve_kbytes > free_kbytes) { 37561640879aSAndrew Shewmaker init_admin_reserve(); 37571640879aSAndrew Shewmaker pr_info("vm.admin_reserve_kbytes reset to %lu\n", 37581640879aSAndrew Shewmaker sysctl_admin_reserve_kbytes); 37591640879aSAndrew Shewmaker } 37601640879aSAndrew Shewmaker break; 37611640879aSAndrew Shewmaker default: 37621640879aSAndrew Shewmaker break; 37631640879aSAndrew Shewmaker } 37641640879aSAndrew Shewmaker return NOTIFY_OK; 37651640879aSAndrew Shewmaker } 37661640879aSAndrew Shewmaker 37671640879aSAndrew Shewmaker static int __meminit init_reserve_notifier(void) 37681640879aSAndrew Shewmaker { 37691eeaa4fdSLiu Shixin if (hotplug_memory_notifier(reserve_mem_notifier, DEFAULT_CALLBACK_PRI)) 3770b1de0d13SMitchel Humpherys pr_err("Failed registering memory add/remove notifier for admin reserve\n"); 37711640879aSAndrew Shewmaker 37721640879aSAndrew Shewmaker return 0; 37731640879aSAndrew Shewmaker } 3774a64fb3cdSPaul Gortmaker subsys_initcall(init_reserve_notifier); 3775