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, 8168f48381SSuren Baghdasaryan unsigned long end, bool mm_wr_locked); 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_flags(struct vma_iterator *vmi, struct vm_area_struct *brkvma, 184763ecb03SLiam R. Howlett unsigned long addr, unsigned long request, unsigned long flags); 1856a6160a7SHeiko Carstens SYSCALL_DEFINE1(brk, unsigned long, brk) 1861da177e4SLinus Torvalds { 1879bc8039eSYang Shi unsigned long newbrk, oldbrk, origbrk; 1881da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 1892e7ce7d3SLiam R. Howlett struct vm_area_struct *brkvma, *next = NULL; 190a5b4592cSJiri Kosina unsigned long min_brk; 191128557ffSMichel Lespinasse bool populate; 1929bc8039eSYang Shi bool downgraded = false; 193897ab3e0SMike Rapoport LIST_HEAD(uf); 19492fed820SLiam R. Howlett struct vma_iterator vmi; 1951da177e4SLinus Torvalds 196d8ed45c5SMichel Lespinasse if (mmap_write_lock_killable(mm)) 197dc0ef0dfSMichal Hocko return -EINTR; 1981da177e4SLinus Torvalds 1999bc8039eSYang Shi origbrk = mm->brk; 2009bc8039eSYang Shi 201a5b4592cSJiri Kosina #ifdef CONFIG_COMPAT_BRK 2025520e894SJiri Kosina /* 2035520e894SJiri Kosina * CONFIG_COMPAT_BRK can still be overridden by setting 2045520e894SJiri Kosina * randomize_va_space to 2, which will still cause mm->start_brk 2055520e894SJiri Kosina * to be arbitrarily shifted 2065520e894SJiri Kosina */ 2074471a675SJiri Kosina if (current->brk_randomized) 2085520e894SJiri Kosina min_brk = mm->start_brk; 2095520e894SJiri Kosina else 2105520e894SJiri Kosina min_brk = mm->end_data; 211a5b4592cSJiri Kosina #else 212a5b4592cSJiri Kosina min_brk = mm->start_brk; 213a5b4592cSJiri Kosina #endif 214a5b4592cSJiri Kosina if (brk < min_brk) 2151da177e4SLinus Torvalds goto out; 2161e624196SRam Gupta 2171e624196SRam Gupta /* 2181e624196SRam Gupta * Check against rlimit here. If this check is done later after the test 2191e624196SRam Gupta * of oldbrk with newbrk then it can escape the test and let the data 2201e624196SRam Gupta * segment grow beyond its set limit the in case where the limit is 2211e624196SRam Gupta * not page aligned -Ram Gupta 2221e624196SRam Gupta */ 2238764b338SCyrill Gorcunov if (check_data_rlimit(rlimit(RLIMIT_DATA), brk, mm->start_brk, 2248764b338SCyrill Gorcunov mm->end_data, mm->start_data)) 2251e624196SRam Gupta goto out; 2261e624196SRam Gupta 2271da177e4SLinus Torvalds newbrk = PAGE_ALIGN(brk); 2281da177e4SLinus Torvalds oldbrk = PAGE_ALIGN(mm->brk); 2299bc8039eSYang Shi if (oldbrk == newbrk) { 2309bc8039eSYang Shi mm->brk = brk; 2319bc8039eSYang Shi goto success; 2329bc8039eSYang Shi } 2331da177e4SLinus Torvalds 2349bc8039eSYang Shi /* 2359bc8039eSYang Shi * Always allow shrinking brk. 23627b26701SLiam R. Howlett * do_vma_munmap() may downgrade mmap_lock to read. 2379bc8039eSYang Shi */ 2381da177e4SLinus Torvalds if (brk <= mm->brk) { 2399bc8039eSYang Shi int ret; 2409bc8039eSYang Shi 2412e7ce7d3SLiam R. Howlett /* Search one past newbrk */ 24292fed820SLiam R. Howlett vma_iter_init(&vmi, mm, newbrk); 24392fed820SLiam R. Howlett brkvma = vma_find(&vmi, oldbrk); 244f5ad5083SJason A. Donenfeld if (!brkvma || brkvma->vm_start >= oldbrk) 2452e7ce7d3SLiam R. Howlett goto out; /* mapping intersects with an existing non-brk vma. */ 2469bc8039eSYang Shi /* 2472e7ce7d3SLiam R. Howlett * mm->brk must be protected by write mmap_lock. 24827b26701SLiam R. Howlett * do_vma_munmap() may downgrade the lock, so update it 24927b26701SLiam R. Howlett * before calling do_vma_munmap(). 2509bc8039eSYang Shi */ 2519bc8039eSYang Shi mm->brk = brk; 25227b26701SLiam R. Howlett ret = do_vma_munmap(&vmi, brkvma, newbrk, oldbrk, &uf, true); 2532e7ce7d3SLiam R. Howlett if (ret == 1) { 2542e7ce7d3SLiam R. Howlett downgraded = true; 2552e7ce7d3SLiam R. Howlett goto success; 2562e7ce7d3SLiam R. Howlett } else if (!ret) 2572e7ce7d3SLiam R. Howlett goto success; 2582e7ce7d3SLiam R. Howlett 2599bc8039eSYang Shi mm->brk = origbrk; 2601da177e4SLinus Torvalds goto out; 2611da177e4SLinus Torvalds } 2621da177e4SLinus Torvalds 2632e7ce7d3SLiam R. Howlett if (check_brk_limits(oldbrk, newbrk - oldbrk)) 2642e7ce7d3SLiam R. Howlett goto out; 2652e7ce7d3SLiam R. Howlett 2662e7ce7d3SLiam R. Howlett /* 2672e7ce7d3SLiam R. Howlett * Only check if the next VMA is within the stack_guard_gap of the 2682e7ce7d3SLiam R. Howlett * expansion area 2692e7ce7d3SLiam R. Howlett */ 27092fed820SLiam R. Howlett vma_iter_init(&vmi, mm, oldbrk); 27192fed820SLiam R. Howlett next = vma_find(&vmi, newbrk + PAGE_SIZE + stack_guard_gap); 2721be7107fSHugh Dickins if (next && newbrk + PAGE_SIZE > vm_start_gap(next)) 2731da177e4SLinus Torvalds goto out; 2741da177e4SLinus Torvalds 27592fed820SLiam R. Howlett brkvma = vma_prev_limit(&vmi, mm->start_brk); 2761da177e4SLinus Torvalds /* Ok, looks good - let it rip. */ 27792fed820SLiam R. Howlett if (do_brk_flags(&vmi, brkvma, oldbrk, newbrk - oldbrk, 0) < 0) 2781da177e4SLinus Torvalds goto out; 2792e7ce7d3SLiam R. Howlett 2801da177e4SLinus Torvalds mm->brk = brk; 2819bc8039eSYang Shi 2829bc8039eSYang Shi success: 283128557ffSMichel Lespinasse populate = newbrk > oldbrk && (mm->def_flags & VM_LOCKED) != 0; 2849bc8039eSYang Shi if (downgraded) 285d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 2869bc8039eSYang Shi else 287d8ed45c5SMichel Lespinasse mmap_write_unlock(mm); 288897ab3e0SMike Rapoport userfaultfd_unmap_complete(mm, &uf); 289128557ffSMichel Lespinasse if (populate) 290128557ffSMichel Lespinasse mm_populate(oldbrk, newbrk - oldbrk); 291128557ffSMichel Lespinasse return brk; 292128557ffSMichel Lespinasse 2931da177e4SLinus Torvalds out: 294d8ed45c5SMichel Lespinasse mmap_write_unlock(mm); 295b7204006SAdrian Huang return origbrk; 2961da177e4SLinus Torvalds } 2971da177e4SLinus Torvalds 298d4af56c5SLiam R. Howlett #if defined(CONFIG_DEBUG_VM_MAPLE_TREE) 299d4af56c5SLiam R. Howlett extern void mt_validate(struct maple_tree *mt); 300d4af56c5SLiam R. Howlett extern void mt_dump(const struct maple_tree *mt); 3011da177e4SLinus Torvalds 302d4af56c5SLiam R. Howlett /* Validate the maple tree */ 303d4af56c5SLiam R. Howlett static void validate_mm_mt(struct mm_struct *mm) 304d4af56c5SLiam R. Howlett { 305d4af56c5SLiam R. Howlett struct maple_tree *mt = &mm->mm_mt; 306763ecb03SLiam R. Howlett struct vm_area_struct *vma_mt; 307d4af56c5SLiam R. Howlett 308d4af56c5SLiam R. Howlett MA_STATE(mas, mt, 0, 0); 309d4af56c5SLiam R. Howlett 310d4af56c5SLiam R. Howlett mt_validate(&mm->mm_mt); 311d4af56c5SLiam R. Howlett mas_for_each(&mas, vma_mt, ULONG_MAX) { 312763ecb03SLiam R. Howlett if ((vma_mt->vm_start != mas.index) || 313763ecb03SLiam R. Howlett (vma_mt->vm_end - 1 != mas.last)) { 314d4af56c5SLiam R. Howlett pr_emerg("issue in %s\n", current->comm); 315d4af56c5SLiam R. Howlett dump_stack(); 316d4af56c5SLiam R. Howlett dump_vma(vma_mt); 317d4af56c5SLiam R. Howlett pr_emerg("mt piv: %p %lu - %lu\n", vma_mt, 318d4af56c5SLiam R. Howlett mas.index, mas.last); 319d4af56c5SLiam R. Howlett pr_emerg("mt vma: %p %lu - %lu\n", vma_mt, 320d4af56c5SLiam R. Howlett vma_mt->vm_start, vma_mt->vm_end); 321d4af56c5SLiam R. Howlett 322d4af56c5SLiam R. Howlett mt_dump(mas.tree); 323d4af56c5SLiam R. Howlett if (vma_mt->vm_end != mas.last + 1) { 324d4af56c5SLiam R. Howlett pr_err("vma: %p vma_mt %lu-%lu\tmt %lu-%lu\n", 325d4af56c5SLiam R. Howlett mm, vma_mt->vm_start, vma_mt->vm_end, 326d4af56c5SLiam R. Howlett mas.index, mas.last); 327d4af56c5SLiam R. Howlett mt_dump(mas.tree); 328d4af56c5SLiam R. Howlett } 329d4af56c5SLiam R. Howlett VM_BUG_ON_MM(vma_mt->vm_end != mas.last + 1, mm); 330d4af56c5SLiam R. Howlett if (vma_mt->vm_start != mas.index) { 331d4af56c5SLiam R. Howlett pr_err("vma: %p vma_mt %p %lu - %lu doesn't match\n", 332d4af56c5SLiam R. Howlett mm, vma_mt, vma_mt->vm_start, vma_mt->vm_end); 333d4af56c5SLiam R. Howlett mt_dump(mas.tree); 334d4af56c5SLiam R. Howlett } 335d4af56c5SLiam R. Howlett VM_BUG_ON_MM(vma_mt->vm_start != mas.index, mm); 336d4af56c5SLiam R. Howlett } 337d4af56c5SLiam R. Howlett } 338d4af56c5SLiam R. Howlett } 3391da177e4SLinus Torvalds 340eafd4dc4SRashika Kheria static void validate_mm(struct mm_struct *mm) 3411da177e4SLinus Torvalds { 3421da177e4SLinus Torvalds int bug = 0; 3431da177e4SLinus Torvalds int i = 0; 344763ecb03SLiam R. Howlett struct vm_area_struct *vma; 345763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 346ff26f70fSAndrew Morton 347524e00b3SLiam R. Howlett validate_mm_mt(mm); 348524e00b3SLiam R. Howlett 349763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 350524e00b3SLiam R. Howlett #ifdef CONFIG_DEBUG_VM_RB 35112352d3cSKonstantin Khlebnikov struct anon_vma *anon_vma = vma->anon_vma; 352ed8ea815SMichel Lespinasse struct anon_vma_chain *avc; 353ff26f70fSAndrew Morton 35412352d3cSKonstantin Khlebnikov if (anon_vma) { 35512352d3cSKonstantin Khlebnikov anon_vma_lock_read(anon_vma); 356ed8ea815SMichel Lespinasse list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 357ed8ea815SMichel Lespinasse anon_vma_interval_tree_verify(avc); 35812352d3cSKonstantin Khlebnikov anon_vma_unlock_read(anon_vma); 35912352d3cSKonstantin Khlebnikov } 360524e00b3SLiam R. Howlett #endif 3611da177e4SLinus Torvalds i++; 3621da177e4SLinus Torvalds } 3635a0768f6SMichel Lespinasse if (i != mm->map_count) { 364763ecb03SLiam R. Howlett pr_emerg("map_count %d mas_for_each %d\n", mm->map_count, i); 3655a0768f6SMichel Lespinasse bug = 1; 3665a0768f6SMichel Lespinasse } 36796dad67fSSasha Levin VM_BUG_ON_MM(bug, mm); 3681da177e4SLinus Torvalds } 369524e00b3SLiam R. Howlett 370524e00b3SLiam R. Howlett #else /* !CONFIG_DEBUG_VM_MAPLE_TREE */ 371d4af56c5SLiam R. Howlett #define validate_mm_mt(root) do { } while (0) 3721da177e4SLinus Torvalds #define validate_mm(mm) do { } while (0) 373524e00b3SLiam R. Howlett #endif /* CONFIG_DEBUG_VM_MAPLE_TREE */ 374d3737187SMichel Lespinasse 375bf181b9fSMichel Lespinasse /* 376bf181b9fSMichel Lespinasse * vma has some anon_vma assigned, and is already inserted on that 377bf181b9fSMichel Lespinasse * anon_vma's interval trees. 378bf181b9fSMichel Lespinasse * 379bf181b9fSMichel Lespinasse * Before updating the vma's vm_start / vm_end / vm_pgoff fields, the 380bf181b9fSMichel Lespinasse * vma must be removed from the anon_vma's interval trees using 381bf181b9fSMichel Lespinasse * anon_vma_interval_tree_pre_update_vma(). 382bf181b9fSMichel Lespinasse * 383bf181b9fSMichel Lespinasse * After the update, the vma will be reinserted using 384bf181b9fSMichel Lespinasse * anon_vma_interval_tree_post_update_vma(). 385bf181b9fSMichel Lespinasse * 386c1e8d7c6SMichel Lespinasse * The entire update must be protected by exclusive mmap_lock and by 387bf181b9fSMichel Lespinasse * the root anon_vma's mutex. 388bf181b9fSMichel Lespinasse */ 389bf181b9fSMichel Lespinasse static inline void 390bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(struct vm_area_struct *vma) 391bf181b9fSMichel Lespinasse { 392bf181b9fSMichel Lespinasse struct anon_vma_chain *avc; 393bf181b9fSMichel Lespinasse 394bf181b9fSMichel Lespinasse list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 395bf181b9fSMichel Lespinasse anon_vma_interval_tree_remove(avc, &avc->anon_vma->rb_root); 396bf181b9fSMichel Lespinasse } 397bf181b9fSMichel Lespinasse 398bf181b9fSMichel Lespinasse static inline void 399bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(struct vm_area_struct *vma) 400bf181b9fSMichel Lespinasse { 401bf181b9fSMichel Lespinasse struct anon_vma_chain *avc; 402bf181b9fSMichel Lespinasse 403bf181b9fSMichel Lespinasse list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 404bf181b9fSMichel Lespinasse anon_vma_interval_tree_insert(avc, &avc->anon_vma->rb_root); 405bf181b9fSMichel Lespinasse } 406bf181b9fSMichel Lespinasse 407e8420a8eSCyril Hrubis static unsigned long count_vma_pages_range(struct mm_struct *mm, 408e8420a8eSCyril Hrubis unsigned long addr, unsigned long end) 409e8420a8eSCyril Hrubis { 4102e3af1dbSMatthew Wilcox (Oracle) VMA_ITERATOR(vmi, mm, addr); 411e8420a8eSCyril Hrubis struct vm_area_struct *vma; 4122e3af1dbSMatthew Wilcox (Oracle) unsigned long nr_pages = 0; 413e8420a8eSCyril Hrubis 4142e3af1dbSMatthew Wilcox (Oracle) for_each_vma_range(vmi, vma, end) { 4152e3af1dbSMatthew Wilcox (Oracle) unsigned long vm_start = max(addr, vma->vm_start); 4162e3af1dbSMatthew Wilcox (Oracle) unsigned long vm_end = min(end, vma->vm_end); 417e8420a8eSCyril Hrubis 4182e3af1dbSMatthew Wilcox (Oracle) nr_pages += PHYS_PFN(vm_end - vm_start); 419e8420a8eSCyril Hrubis } 420e8420a8eSCyril Hrubis 421e8420a8eSCyril Hrubis return nr_pages; 422e8420a8eSCyril Hrubis } 423e8420a8eSCyril Hrubis 424c154124fSLiam R. Howlett static void __vma_link_file(struct vm_area_struct *vma, 425c154124fSLiam R. Howlett struct address_space *mapping) 4261da177e4SLinus Torvalds { 4271da177e4SLinus Torvalds if (vma->vm_flags & VM_SHARED) 428cf508b58SMiaohe Lin mapping_allow_writable(mapping); 4291da177e4SLinus Torvalds 4301da177e4SLinus Torvalds flush_dcache_mmap_lock(mapping); 4316b2dbba8SMichel Lespinasse vma_interval_tree_insert(vma, &mapping->i_mmap); 4321da177e4SLinus Torvalds flush_dcache_mmap_unlock(mapping); 4331da177e4SLinus Torvalds } 4341da177e4SLinus Torvalds 435763ecb03SLiam R. Howlett static int vma_link(struct mm_struct *mm, struct vm_area_struct *vma) 4361da177e4SLinus Torvalds { 43779e4f2caSLiam R. Howlett VMA_ITERATOR(vmi, mm, 0); 4381da177e4SLinus Torvalds struct address_space *mapping = NULL; 4391da177e4SLinus Torvalds 44079e4f2caSLiam R. Howlett if (vma_iter_prealloc(&vmi)) 441d4af56c5SLiam R. Howlett return -ENOMEM; 442d4af56c5SLiam R. Howlett 44364ac4940SHuang Shijie if (vma->vm_file) { 4441da177e4SLinus Torvalds mapping = vma->vm_file->f_mapping; 44583cde9e8SDavidlohr Bueso i_mmap_lock_write(mapping); 44664ac4940SHuang Shijie } 4471da177e4SLinus Torvalds 44879e4f2caSLiam R. Howlett vma_iter_store(&vmi, vma); 4491da177e4SLinus Torvalds 450c154124fSLiam R. Howlett if (mapping) { 451c154124fSLiam R. Howlett __vma_link_file(vma, mapping); 45283cde9e8SDavidlohr Bueso i_mmap_unlock_write(mapping); 453c154124fSLiam R. Howlett } 4541da177e4SLinus Torvalds 4551da177e4SLinus Torvalds mm->map_count++; 4561da177e4SLinus Torvalds validate_mm(mm); 457d4af56c5SLiam R. Howlett return 0; 4581da177e4SLinus Torvalds } 4591da177e4SLinus Torvalds 4601da177e4SLinus Torvalds /* 46168cefec5SLiam R. Howlett * init_multi_vma_prep() - Initializer for struct vma_prepare 46268cefec5SLiam R. Howlett * @vp: The vma_prepare struct 46368cefec5SLiam R. Howlett * @vma: The vma that will be altered once locked 46468cefec5SLiam R. Howlett * @next: The next vma if it is to be adjusted 46568cefec5SLiam R. Howlett * @remove: The first vma to be removed 46668cefec5SLiam R. Howlett * @remove2: The second vma to be removed 46768cefec5SLiam R. Howlett */ 46868cefec5SLiam R. Howlett static inline void init_multi_vma_prep(struct vma_prepare *vp, 46968cefec5SLiam R. Howlett struct vm_area_struct *vma, struct vm_area_struct *next, 47068cefec5SLiam R. Howlett struct vm_area_struct *remove, struct vm_area_struct *remove2) 47168cefec5SLiam R. Howlett { 47268cefec5SLiam R. Howlett memset(vp, 0, sizeof(struct vma_prepare)); 47368cefec5SLiam R. Howlett vp->vma = vma; 47468cefec5SLiam R. Howlett vp->anon_vma = vma->anon_vma; 47568cefec5SLiam R. Howlett vp->remove = remove; 47668cefec5SLiam R. Howlett vp->remove2 = remove2; 47768cefec5SLiam R. Howlett vp->adj_next = next; 47868cefec5SLiam R. Howlett if (!vp->anon_vma && next) 47968cefec5SLiam R. Howlett vp->anon_vma = next->anon_vma; 48068cefec5SLiam R. Howlett 48168cefec5SLiam R. Howlett vp->file = vma->vm_file; 48268cefec5SLiam R. Howlett if (vp->file) 48368cefec5SLiam R. Howlett vp->mapping = vma->vm_file->f_mapping; 48468cefec5SLiam R. Howlett 48568cefec5SLiam R. Howlett } 48668cefec5SLiam R. Howlett 48768cefec5SLiam R. Howlett /* 48868cefec5SLiam R. Howlett * init_vma_prep() - Initializer wrapper for vma_prepare struct 48968cefec5SLiam R. Howlett * @vp: The vma_prepare struct 49068cefec5SLiam R. Howlett * @vma: The vma that will be altered once locked 49168cefec5SLiam R. Howlett */ 49268cefec5SLiam R. Howlett static inline void init_vma_prep(struct vma_prepare *vp, 49368cefec5SLiam R. Howlett struct vm_area_struct *vma) 49468cefec5SLiam R. Howlett { 49568cefec5SLiam R. Howlett init_multi_vma_prep(vp, vma, NULL, NULL, NULL); 49668cefec5SLiam R. Howlett } 49768cefec5SLiam R. Howlett 49868cefec5SLiam R. Howlett 49968cefec5SLiam R. Howlett /* 500440703e0SLiam R. Howlett * vma_prepare() - Helper function for handling locking VMAs prior to altering 501440703e0SLiam R. Howlett * @vp: The initialized vma_prepare struct 502440703e0SLiam R. Howlett */ 503440703e0SLiam R. Howlett static inline void vma_prepare(struct vma_prepare *vp) 504440703e0SLiam R. Howlett { 50510fca64aSSuren Baghdasaryan vma_start_write(vp->vma); 50610fca64aSSuren Baghdasaryan if (vp->adj_next) 50710fca64aSSuren Baghdasaryan vma_start_write(vp->adj_next); 50810fca64aSSuren Baghdasaryan /* vp->insert is always a newly created VMA, no need for locking */ 50910fca64aSSuren Baghdasaryan if (vp->remove) 51010fca64aSSuren Baghdasaryan vma_start_write(vp->remove); 51110fca64aSSuren Baghdasaryan if (vp->remove2) 51210fca64aSSuren Baghdasaryan vma_start_write(vp->remove2); 51310fca64aSSuren Baghdasaryan 514440703e0SLiam R. Howlett if (vp->file) { 515440703e0SLiam R. Howlett uprobe_munmap(vp->vma, vp->vma->vm_start, vp->vma->vm_end); 516440703e0SLiam R. Howlett 517440703e0SLiam R. Howlett if (vp->adj_next) 518440703e0SLiam R. Howlett uprobe_munmap(vp->adj_next, vp->adj_next->vm_start, 519440703e0SLiam R. Howlett vp->adj_next->vm_end); 520440703e0SLiam R. Howlett 521440703e0SLiam R. Howlett i_mmap_lock_write(vp->mapping); 522440703e0SLiam R. Howlett if (vp->insert && vp->insert->vm_file) { 523440703e0SLiam R. Howlett /* 524440703e0SLiam R. Howlett * Put into interval tree now, so instantiated pages 525440703e0SLiam R. Howlett * are visible to arm/parisc __flush_dcache_page 526440703e0SLiam R. Howlett * throughout; but we cannot insert into address 527440703e0SLiam R. Howlett * space until vma start or end is updated. 528440703e0SLiam R. Howlett */ 529440703e0SLiam R. Howlett __vma_link_file(vp->insert, 530440703e0SLiam R. Howlett vp->insert->vm_file->f_mapping); 531440703e0SLiam R. Howlett } 532440703e0SLiam R. Howlett } 533440703e0SLiam R. Howlett 534440703e0SLiam R. Howlett if (vp->anon_vma) { 535440703e0SLiam R. Howlett anon_vma_lock_write(vp->anon_vma); 536440703e0SLiam R. Howlett anon_vma_interval_tree_pre_update_vma(vp->vma); 537440703e0SLiam R. Howlett if (vp->adj_next) 538440703e0SLiam R. Howlett anon_vma_interval_tree_pre_update_vma(vp->adj_next); 539440703e0SLiam R. Howlett } 540440703e0SLiam R. Howlett 541440703e0SLiam R. Howlett if (vp->file) { 542440703e0SLiam R. Howlett flush_dcache_mmap_lock(vp->mapping); 543440703e0SLiam R. Howlett vma_interval_tree_remove(vp->vma, &vp->mapping->i_mmap); 544440703e0SLiam R. Howlett if (vp->adj_next) 545440703e0SLiam R. Howlett vma_interval_tree_remove(vp->adj_next, 546440703e0SLiam R. Howlett &vp->mapping->i_mmap); 547440703e0SLiam R. Howlett } 548440703e0SLiam R. Howlett 549440703e0SLiam R. Howlett } 550440703e0SLiam R. Howlett 551440703e0SLiam R. Howlett /* 552440703e0SLiam R. Howlett * vma_complete- Helper function for handling the unlocking after altering VMAs, 553440703e0SLiam R. Howlett * or for inserting a VMA. 554440703e0SLiam R. Howlett * 555440703e0SLiam R. Howlett * @vp: The vma_prepare struct 556440703e0SLiam R. Howlett * @vmi: The vma iterator 557440703e0SLiam R. Howlett * @mm: The mm_struct 558440703e0SLiam R. Howlett */ 559440703e0SLiam R. Howlett static inline void vma_complete(struct vma_prepare *vp, 560440703e0SLiam R. Howlett struct vma_iterator *vmi, struct mm_struct *mm) 561440703e0SLiam R. Howlett { 562440703e0SLiam R. Howlett if (vp->file) { 563440703e0SLiam R. Howlett if (vp->adj_next) 564440703e0SLiam R. Howlett vma_interval_tree_insert(vp->adj_next, 565440703e0SLiam R. Howlett &vp->mapping->i_mmap); 566440703e0SLiam R. Howlett vma_interval_tree_insert(vp->vma, &vp->mapping->i_mmap); 567440703e0SLiam R. Howlett flush_dcache_mmap_unlock(vp->mapping); 568440703e0SLiam R. Howlett } 569440703e0SLiam R. Howlett 570440703e0SLiam R. Howlett if (vp->remove && vp->file) { 571440703e0SLiam R. Howlett __remove_shared_vm_struct(vp->remove, vp->file, vp->mapping); 572440703e0SLiam R. Howlett if (vp->remove2) 573440703e0SLiam R. Howlett __remove_shared_vm_struct(vp->remove2, vp->file, 574440703e0SLiam R. Howlett vp->mapping); 575440703e0SLiam R. Howlett } else if (vp->insert) { 576440703e0SLiam R. Howlett /* 577440703e0SLiam R. Howlett * split_vma has split insert from vma, and needs 578440703e0SLiam R. Howlett * us to insert it before dropping the locks 579440703e0SLiam R. Howlett * (it may either follow vma or precede it). 580440703e0SLiam R. Howlett */ 581440703e0SLiam R. Howlett vma_iter_store(vmi, vp->insert); 582440703e0SLiam R. Howlett mm->map_count++; 583440703e0SLiam R. Howlett } 584440703e0SLiam R. Howlett 585440703e0SLiam R. Howlett if (vp->anon_vma) { 586440703e0SLiam R. Howlett anon_vma_interval_tree_post_update_vma(vp->vma); 587440703e0SLiam R. Howlett if (vp->adj_next) 588440703e0SLiam R. Howlett anon_vma_interval_tree_post_update_vma(vp->adj_next); 589440703e0SLiam R. Howlett anon_vma_unlock_write(vp->anon_vma); 590440703e0SLiam R. Howlett } 591440703e0SLiam R. Howlett 592440703e0SLiam R. Howlett if (vp->file) { 593440703e0SLiam R. Howlett i_mmap_unlock_write(vp->mapping); 594440703e0SLiam R. Howlett uprobe_mmap(vp->vma); 595440703e0SLiam R. Howlett 596440703e0SLiam R. Howlett if (vp->adj_next) 597440703e0SLiam R. Howlett uprobe_mmap(vp->adj_next); 598440703e0SLiam R. Howlett } 599440703e0SLiam R. Howlett 600440703e0SLiam R. Howlett if (vp->remove) { 601440703e0SLiam R. Howlett again: 602440703e0SLiam R. Howlett if (vp->file) { 603440703e0SLiam R. Howlett uprobe_munmap(vp->remove, vp->remove->vm_start, 604440703e0SLiam R. Howlett vp->remove->vm_end); 605440703e0SLiam R. Howlett fput(vp->file); 606440703e0SLiam R. Howlett } 607440703e0SLiam R. Howlett if (vp->remove->anon_vma) 608440703e0SLiam R. Howlett anon_vma_merge(vp->vma, vp->remove); 609440703e0SLiam R. Howlett mm->map_count--; 610440703e0SLiam R. Howlett mpol_put(vma_policy(vp->remove)); 611440703e0SLiam R. Howlett if (!vp->remove2) 612440703e0SLiam R. Howlett WARN_ON_ONCE(vp->vma->vm_end < vp->remove->vm_end); 613440703e0SLiam R. Howlett vm_area_free(vp->remove); 614440703e0SLiam R. Howlett 615440703e0SLiam R. Howlett /* 616440703e0SLiam R. Howlett * In mprotect's case 6 (see comments on vma_merge), 6175ff783f1SVlastimil Babka * we are removing both mid and next vmas 618440703e0SLiam R. Howlett */ 619440703e0SLiam R. Howlett if (vp->remove2) { 620440703e0SLiam R. Howlett vp->remove = vp->remove2; 621440703e0SLiam R. Howlett vp->remove2 = NULL; 622440703e0SLiam R. Howlett goto again; 623440703e0SLiam R. Howlett } 624440703e0SLiam R. Howlett } 625440703e0SLiam R. Howlett if (vp->insert && vp->file) 626440703e0SLiam R. Howlett uprobe_mmap(vp->insert); 627440703e0SLiam R. Howlett } 628440703e0SLiam R. Howlett 629440703e0SLiam R. Howlett /* 63004241ffeSLiam R. Howlett * dup_anon_vma() - Helper function to duplicate anon_vma 63104241ffeSLiam R. Howlett * @dst: The destination VMA 63204241ffeSLiam R. Howlett * @src: The source VMA 63304241ffeSLiam R. Howlett * 63404241ffeSLiam R. Howlett * Returns: 0 on success. 63504241ffeSLiam R. Howlett */ 63604241ffeSLiam R. Howlett static inline int dup_anon_vma(struct vm_area_struct *dst, 63704241ffeSLiam R. Howlett struct vm_area_struct *src) 63804241ffeSLiam R. Howlett { 63904241ffeSLiam R. Howlett /* 64004241ffeSLiam R. Howlett * Easily overlooked: when mprotect shifts the boundary, make sure the 64104241ffeSLiam R. Howlett * expanding vma has anon_vma set if the shrinking vma had, to cover any 64204241ffeSLiam R. Howlett * anon pages imported. 64304241ffeSLiam R. Howlett */ 64404241ffeSLiam R. Howlett if (src->anon_vma && !dst->anon_vma) { 64504241ffeSLiam R. Howlett dst->anon_vma = src->anon_vma; 64604241ffeSLiam R. Howlett return anon_vma_clone(dst, src); 64704241ffeSLiam R. Howlett } 64804241ffeSLiam R. Howlett 64904241ffeSLiam R. Howlett return 0; 65004241ffeSLiam R. Howlett } 65104241ffeSLiam R. Howlett 65204241ffeSLiam R. Howlett /* 6539303d3e1SLiam R. Howlett * vma_expand - Expand an existing VMA 6549303d3e1SLiam R. Howlett * 6559303d3e1SLiam R. Howlett * @vmi: The vma iterator 6569303d3e1SLiam R. Howlett * @vma: The vma to expand 6579303d3e1SLiam R. Howlett * @start: The start of the vma 6589303d3e1SLiam R. Howlett * @end: The exclusive end of the vma 6599303d3e1SLiam R. Howlett * @pgoff: The page offset of vma 6609303d3e1SLiam R. Howlett * @next: The current of next vma. 6619303d3e1SLiam R. Howlett * 6629303d3e1SLiam R. Howlett * Expand @vma to @start and @end. Can expand off the start and end. Will 6639303d3e1SLiam R. Howlett * expand over @next if it's different from @vma and @end == @next->vm_end. 6649303d3e1SLiam R. Howlett * Checking if the @vma can expand and merge with @next needs to be handled by 6659303d3e1SLiam R. Howlett * the caller. 6669303d3e1SLiam R. Howlett * 6679303d3e1SLiam R. Howlett * Returns: 0 on success 6689303d3e1SLiam R. Howlett */ 6697c9813e8SLiam R. Howlett int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma, 6709303d3e1SLiam R. Howlett unsigned long start, unsigned long end, pgoff_t pgoff, 6719303d3e1SLiam R. Howlett struct vm_area_struct *next) 6729303d3e1SLiam R. Howlett { 67368cefec5SLiam R. Howlett bool remove_next = false; 6749303d3e1SLiam R. Howlett struct vma_prepare vp; 6759303d3e1SLiam R. Howlett 6769303d3e1SLiam R. Howlett if (next && (vma != next) && (end == next->vm_end)) { 67704241ffeSLiam R. Howlett int ret; 6789303d3e1SLiam R. Howlett 67904241ffeSLiam R. Howlett remove_next = true; 68004241ffeSLiam R. Howlett ret = dup_anon_vma(vma, next); 68104241ffeSLiam R. Howlett if (ret) 68204241ffeSLiam R. Howlett return ret; 6839303d3e1SLiam R. Howlett } 6849303d3e1SLiam R. Howlett 68568cefec5SLiam R. Howlett init_multi_vma_prep(&vp, vma, NULL, remove_next ? next : NULL, NULL); 6869303d3e1SLiam R. Howlett /* Not merging but overwriting any part of next is not handled. */ 6879303d3e1SLiam R. Howlett VM_WARN_ON(next && !vp.remove && 6889303d3e1SLiam R. Howlett next != vma && end > next->vm_start); 6899303d3e1SLiam R. Howlett /* Only handles expanding */ 6909303d3e1SLiam R. Howlett VM_WARN_ON(vma->vm_start < start || vma->vm_end > end); 6919303d3e1SLiam R. Howlett 6929303d3e1SLiam R. Howlett if (vma_iter_prealloc(vmi)) 6939303d3e1SLiam R. Howlett goto nomem; 6949303d3e1SLiam R. Howlett 695ccf1d78dSSuren Baghdasaryan vma_prepare(&vp); 6969303d3e1SLiam R. Howlett vma_adjust_trans_huge(vma, start, end, 0); 6979303d3e1SLiam R. Howlett /* VMA iterator points to previous, so set to start if necessary */ 6989303d3e1SLiam R. Howlett if (vma_iter_addr(vmi) != start) 6999303d3e1SLiam R. Howlett vma_iter_set(vmi, start); 7009303d3e1SLiam R. Howlett 7019303d3e1SLiam R. Howlett vma->vm_start = start; 7029303d3e1SLiam R. Howlett vma->vm_end = end; 7039303d3e1SLiam R. Howlett vma->vm_pgoff = pgoff; 7049303d3e1SLiam R. Howlett /* Note: mas must be pointing to the expanding VMA */ 7059303d3e1SLiam R. Howlett vma_iter_store(vmi, vma); 7069303d3e1SLiam R. Howlett 7079303d3e1SLiam R. Howlett vma_complete(&vp, vmi, vma->vm_mm); 7089303d3e1SLiam R. Howlett validate_mm(vma->vm_mm); 7099303d3e1SLiam R. Howlett return 0; 7109303d3e1SLiam R. Howlett 7119303d3e1SLiam R. Howlett nomem: 7129303d3e1SLiam R. Howlett return -ENOMEM; 7139303d3e1SLiam R. Howlett } 714cf51e86dSLiam R. Howlett 715cf51e86dSLiam R. Howlett /* 716cf51e86dSLiam R. Howlett * vma_shrink() - Reduce an existing VMAs memory area 717cf51e86dSLiam R. Howlett * @vmi: The vma iterator 718cf51e86dSLiam R. Howlett * @vma: The VMA to modify 719cf51e86dSLiam R. Howlett * @start: The new start 720cf51e86dSLiam R. Howlett * @end: The new end 721cf51e86dSLiam R. Howlett * 722cf51e86dSLiam R. Howlett * Returns: 0 on success, -ENOMEM otherwise 723cf51e86dSLiam R. Howlett */ 724cf51e86dSLiam R. Howlett int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma, 725cf51e86dSLiam R. Howlett unsigned long start, unsigned long end, pgoff_t pgoff) 726cf51e86dSLiam R. Howlett { 727cf51e86dSLiam R. Howlett struct vma_prepare vp; 728cf51e86dSLiam R. Howlett 729cf51e86dSLiam R. Howlett WARN_ON((vma->vm_start != start) && (vma->vm_end != end)); 730cf51e86dSLiam R. Howlett 731cf51e86dSLiam R. Howlett if (vma_iter_prealloc(vmi)) 732cf51e86dSLiam R. Howlett return -ENOMEM; 733cf51e86dSLiam R. Howlett 734cf51e86dSLiam R. Howlett init_vma_prep(&vp, vma); 735cf51e86dSLiam R. Howlett vma_prepare(&vp); 736ccf1d78dSSuren Baghdasaryan vma_adjust_trans_huge(vma, start, end, 0); 737cf51e86dSLiam R. Howlett 738cf51e86dSLiam R. Howlett if (vma->vm_start < start) 739cf51e86dSLiam R. Howlett vma_iter_clear(vmi, vma->vm_start, start); 740cf51e86dSLiam R. Howlett 741cf51e86dSLiam R. Howlett if (vma->vm_end > end) 742cf51e86dSLiam R. Howlett vma_iter_clear(vmi, end, vma->vm_end); 743cf51e86dSLiam R. Howlett 744cf51e86dSLiam R. Howlett vma->vm_start = start; 745cf51e86dSLiam R. Howlett vma->vm_end = end; 746cf51e86dSLiam R. Howlett vma->vm_pgoff = pgoff; 747cf51e86dSLiam R. Howlett vma_complete(&vp, vmi, vma->vm_mm); 748cf51e86dSLiam R. Howlett validate_mm(vma->vm_mm); 749cf51e86dSLiam R. Howlett return 0; 750cf51e86dSLiam R. Howlett } 751cf51e86dSLiam R. Howlett 7529303d3e1SLiam R. Howlett /* 7531da177e4SLinus Torvalds * If the vma has a ->close operation then the driver probably needs to release 754714965caSVlastimil Babka * per-vma resources, so we don't attempt to merge those if the caller indicates 755714965caSVlastimil Babka * the current vma may be removed as part of the merge. 7561da177e4SLinus Torvalds */ 7572dbf4010SVlastimil Babka static inline bool is_mergeable_vma(struct vm_area_struct *vma, 75819a809afSAndrea Arcangeli struct file *file, unsigned long vm_flags, 7599a10064fSColin Cross struct vm_userfaultfd_ctx vm_userfaultfd_ctx, 760714965caSVlastimil Babka struct anon_vma_name *anon_name, bool may_remove_vma) 7611da177e4SLinus Torvalds { 76234228d47SCyrill Gorcunov /* 76334228d47SCyrill Gorcunov * VM_SOFTDIRTY should not prevent from VMA merging, if we 76434228d47SCyrill Gorcunov * match the flags but dirty bit -- the caller should mark 76534228d47SCyrill Gorcunov * merged VMA as dirty. If dirty bit won't be excluded from 7668bb4e7a2SWei Yang * comparison, we increase pressure on the memory system forcing 76734228d47SCyrill Gorcunov * the kernel to generate new VMAs when old one could be 76834228d47SCyrill Gorcunov * extended instead. 76934228d47SCyrill Gorcunov */ 77034228d47SCyrill Gorcunov if ((vma->vm_flags ^ vm_flags) & ~VM_SOFTDIRTY) 7712dbf4010SVlastimil Babka return false; 7721da177e4SLinus Torvalds if (vma->vm_file != file) 7732dbf4010SVlastimil Babka return false; 774714965caSVlastimil Babka if (may_remove_vma && vma->vm_ops && vma->vm_ops->close) 7752dbf4010SVlastimil Babka return false; 77619a809afSAndrea Arcangeli if (!is_mergeable_vm_userfaultfd_ctx(vma, vm_userfaultfd_ctx)) 7772dbf4010SVlastimil Babka return false; 7785c26f6acSSuren Baghdasaryan if (!anon_vma_name_eq(anon_vma_name(vma), anon_name)) 7792dbf4010SVlastimil Babka return false; 7802dbf4010SVlastimil Babka return true; 7811da177e4SLinus Torvalds } 7821da177e4SLinus Torvalds 7832dbf4010SVlastimil Babka static inline bool is_mergeable_anon_vma(struct anon_vma *anon_vma1, 7842dbf4010SVlastimil Babka struct anon_vma *anon_vma2, struct vm_area_struct *vma) 7851da177e4SLinus Torvalds { 786965f55deSShaohua Li /* 787965f55deSShaohua Li * The list_is_singular() test is to avoid merging VMA cloned from 788965f55deSShaohua Li * parents. This can improve scalability caused by anon_vma lock. 789965f55deSShaohua Li */ 790965f55deSShaohua Li if ((!anon_vma1 || !anon_vma2) && (!vma || 791965f55deSShaohua Li list_is_singular(&vma->anon_vma_chain))) 7922dbf4010SVlastimil Babka return true; 793965f55deSShaohua Li return anon_vma1 == anon_vma2; 7941da177e4SLinus Torvalds } 7951da177e4SLinus Torvalds 7961da177e4SLinus Torvalds /* 7971da177e4SLinus Torvalds * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) 7981da177e4SLinus Torvalds * in front of (at a lower virtual address and file offset than) the vma. 7991da177e4SLinus Torvalds * 8001da177e4SLinus Torvalds * We cannot merge two vmas if they have differently assigned (non-NULL) 8011da177e4SLinus Torvalds * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. 8021da177e4SLinus Torvalds * 8031da177e4SLinus Torvalds * We don't check here for the merged mmap wrapping around the end of pagecache 80445e55300SPeter Collingbourne * indices (16TB on ia32) because do_mmap() does not permit mmap's which 8051da177e4SLinus Torvalds * wrap, nor mmaps which cover the final page at index -1UL. 806714965caSVlastimil Babka * 807714965caSVlastimil Babka * We assume the vma may be removed as part of the merge. 8081da177e4SLinus Torvalds */ 8092dbf4010SVlastimil Babka static bool 8101da177e4SLinus Torvalds can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags, 81119a809afSAndrea Arcangeli struct anon_vma *anon_vma, struct file *file, 8122dbf4010SVlastimil Babka pgoff_t vm_pgoff, struct vm_userfaultfd_ctx vm_userfaultfd_ctx, 8135c26f6acSSuren Baghdasaryan struct anon_vma_name *anon_name) 8141da177e4SLinus Torvalds { 815714965caSVlastimil Babka if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx, anon_name, true) && 816965f55deSShaohua Li is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { 8171da177e4SLinus Torvalds if (vma->vm_pgoff == vm_pgoff) 8182dbf4010SVlastimil Babka return true; 8191da177e4SLinus Torvalds } 8202dbf4010SVlastimil Babka return false; 8211da177e4SLinus Torvalds } 8221da177e4SLinus Torvalds 8231da177e4SLinus Torvalds /* 8241da177e4SLinus Torvalds * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) 8251da177e4SLinus Torvalds * beyond (at a higher virtual address and file offset than) the vma. 8261da177e4SLinus Torvalds * 8271da177e4SLinus Torvalds * We cannot merge two vmas if they have differently assigned (non-NULL) 8281da177e4SLinus Torvalds * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. 829714965caSVlastimil Babka * 830714965caSVlastimil Babka * We assume that vma is not removed as part of the merge. 8311da177e4SLinus Torvalds */ 8322dbf4010SVlastimil Babka static bool 8331da177e4SLinus Torvalds can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, 83419a809afSAndrea Arcangeli struct anon_vma *anon_vma, struct file *file, 8352dbf4010SVlastimil Babka pgoff_t vm_pgoff, struct vm_userfaultfd_ctx vm_userfaultfd_ctx, 8365c26f6acSSuren Baghdasaryan struct anon_vma_name *anon_name) 8371da177e4SLinus Torvalds { 838714965caSVlastimil Babka if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx, anon_name, false) && 839965f55deSShaohua Li is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { 8401da177e4SLinus Torvalds pgoff_t vm_pglen; 841d6e93217SLibin vm_pglen = vma_pages(vma); 8421da177e4SLinus Torvalds if (vma->vm_pgoff + vm_pglen == vm_pgoff) 8432dbf4010SVlastimil Babka return true; 8441da177e4SLinus Torvalds } 8452dbf4010SVlastimil Babka return false; 8461da177e4SLinus Torvalds } 8471da177e4SLinus Torvalds 8481da177e4SLinus Torvalds /* 8499a10064fSColin Cross * Given a mapping request (addr,end,vm_flags,file,pgoff,anon_name), 8509a10064fSColin Cross * figure out whether that can be merged with its predecessor or its 8519a10064fSColin Cross * successor. Or both (it neatly fills a hole). 8521da177e4SLinus Torvalds * 8531da177e4SLinus Torvalds * In most cases - when called for mmap, brk or mremap - [addr,end) is 8541da177e4SLinus Torvalds * certain not to be mapped by the time vma_merge is called; but when 8551da177e4SLinus Torvalds * called for mprotect, it is certain to be already mapped (either at 8561da177e4SLinus Torvalds * an offset within prev, or at the start of next), and the flags of 8571da177e4SLinus Torvalds * this area are about to be changed to vm_flags - and the no-change 8581da177e4SLinus Torvalds * case has already been eliminated. 8591da177e4SLinus Torvalds * 860fcfccd91SLorenzo Stoakes * The following mprotect cases have to be considered, where **** is 8611da177e4SLinus Torvalds * the area passed down from mprotect_fixup, never extending beyond one 862fcfccd91SLorenzo Stoakes * vma, PPPP is the previous vma, CCCC is a concurrent vma that starts 863fcfccd91SLorenzo Stoakes * at the same address as **** and is of the same or larger span, and 864fcfccd91SLorenzo Stoakes * NNNN the next vma after ****: 8651da177e4SLinus Torvalds * 866fcfccd91SLorenzo Stoakes * **** **** **** 867fcfccd91SLorenzo Stoakes * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPCCCCCC 8685d42ab29SWei Yang * cannot merge might become might become 869fcfccd91SLorenzo Stoakes * PPNNNNNNNNNN PPPPPPPPPPCC 8705d42ab29SWei Yang * mmap, brk or case 4 below case 5 below 8715d42ab29SWei Yang * mremap move: 872fcfccd91SLorenzo Stoakes * **** **** 873fcfccd91SLorenzo Stoakes * PPPP NNNN PPPPCCCCNNNN 8745d42ab29SWei Yang * might become might become 8755d42ab29SWei Yang * PPPPPPPPPPPP 1 or PPPPPPPPPPPP 6 or 876fcfccd91SLorenzo Stoakes * PPPPPPPPNNNN 2 or PPPPPPPPNNNN 7 or 877fcfccd91SLorenzo Stoakes * PPPPNNNNNNNN 3 PPPPNNNNNNNN 8 8781da177e4SLinus Torvalds * 879fcfccd91SLorenzo Stoakes * It is important for case 8 that the vma CCCC overlapping the 880fcfccd91SLorenzo Stoakes * region **** is never going to extended over NNNN. Instead NNNN must 881fcfccd91SLorenzo Stoakes * be extended in region **** and CCCC must be removed. This way in 8820503ea8fSLiam R. Howlett * all cases where vma_merge succeeds, the moment vma_merge drops the 883e86f15eeSAndrea Arcangeli * rmap_locks, the properties of the merged vma will be already 884e86f15eeSAndrea Arcangeli * correct for the whole merged range. Some of those properties like 885e86f15eeSAndrea Arcangeli * vm_page_prot/vm_flags may be accessed by rmap_walks and they must 886e86f15eeSAndrea Arcangeli * be correct for the whole merged range immediately after the 887fcfccd91SLorenzo Stoakes * rmap_locks are released. Otherwise if NNNN would be removed and 888fcfccd91SLorenzo Stoakes * CCCC would be extended over the NNNN range, remove_migration_ptes 889e86f15eeSAndrea Arcangeli * or other rmap walkers (if working on addresses beyond the "end" 890fcfccd91SLorenzo Stoakes * parameter) may establish ptes with the wrong permissions of CCCC 891fcfccd91SLorenzo Stoakes * instead of the right permissions of NNNN. 8920503ea8fSLiam R. Howlett * 8930503ea8fSLiam R. Howlett * In the code below: 8940503ea8fSLiam R. Howlett * PPPP is represented by *prev 895fcfccd91SLorenzo Stoakes * CCCC is represented by *curr or not represented at all (NULL) 896fcfccd91SLorenzo Stoakes * NNNN is represented by *next or not represented at all (NULL) 897fcfccd91SLorenzo Stoakes * **** is not represented - it will be merged and the vma containing the 8989e8a39d2SVlastimil Babka * area is returned, or the function will return NULL 8991da177e4SLinus Torvalds */ 9009760ebffSLiam R. Howlett struct vm_area_struct *vma_merge(struct vma_iterator *vmi, struct mm_struct *mm, 9011da177e4SLinus Torvalds struct vm_area_struct *prev, unsigned long addr, 9021da177e4SLinus Torvalds unsigned long end, unsigned long vm_flags, 9031da177e4SLinus Torvalds struct anon_vma *anon_vma, struct file *file, 90419a809afSAndrea Arcangeli pgoff_t pgoff, struct mempolicy *policy, 9059a10064fSColin Cross struct vm_userfaultfd_ctx vm_userfaultfd_ctx, 9065c26f6acSSuren Baghdasaryan struct anon_vma_name *anon_name) 9071da177e4SLinus Torvalds { 908b0729ae0SLorenzo Stoakes struct vm_area_struct *curr, *next, *res; 9090503ea8fSLiam R. Howlett struct vm_area_struct *vma, *adjust, *remove, *remove2; 9100173db4fSLorenzo Stoakes struct vma_prepare vp; 9110173db4fSLorenzo Stoakes pgoff_t vma_pgoff; 9120173db4fSLorenzo Stoakes int err = 0; 913eef19944SJakub Matěna bool merge_prev = false; 914eef19944SJakub Matěna bool merge_next = false; 9150503ea8fSLiam R. Howlett bool vma_expanded = false; 9160503ea8fSLiam R. Howlett unsigned long vma_start = addr; 9170173db4fSLorenzo Stoakes unsigned long vma_end = end; 9180173db4fSLorenzo Stoakes pgoff_t pglen = (end - addr) >> PAGE_SHIFT; 9190173db4fSLorenzo Stoakes long adj_start = 0; 9201da177e4SLinus Torvalds 9210503ea8fSLiam R. Howlett validate_mm(mm); 9221da177e4SLinus Torvalds /* 9231da177e4SLinus Torvalds * We later require that vma->vm_flags == vm_flags, 9241da177e4SLinus Torvalds * so this tests vma->vm_flags & VM_SPECIAL, too. 9251da177e4SLinus Torvalds */ 9261da177e4SLinus Torvalds if (vm_flags & VM_SPECIAL) 9271da177e4SLinus Torvalds return NULL; 9281da177e4SLinus Torvalds 92900cd00a6SLorenzo Stoakes /* Does the input range span an existing VMA? (cases 5 - 8) */ 93000cd00a6SLorenzo Stoakes curr = find_vma_intersection(mm, prev ? prev->vm_end : 0, end); 9311da177e4SLinus Torvalds 93200cd00a6SLorenzo Stoakes if (!curr || /* cases 1 - 4 */ 93300cd00a6SLorenzo Stoakes end == curr->vm_end) /* cases 6 - 8, adjacent VMA */ 93400cd00a6SLorenzo Stoakes next = vma_lookup(mm, end); 93500cd00a6SLorenzo Stoakes else 93600cd00a6SLorenzo Stoakes next = NULL; /* case 5 */ 9379e8a39d2SVlastimil Babka 9380503ea8fSLiam R. Howlett if (prev) { 9390503ea8fSLiam R. Howlett vma_start = prev->vm_start; 9400503ea8fSLiam R. Howlett vma_pgoff = prev->vm_pgoff; 9410173db4fSLorenzo Stoakes 942eef19944SJakub Matěna /* Can we merge the predecessor? */ 9430173db4fSLorenzo Stoakes if (addr == prev->vm_end && mpol_equal(vma_policy(prev), policy) 9440503ea8fSLiam R. Howlett && can_vma_merge_after(prev, vm_flags, anon_vma, file, 9450503ea8fSLiam R. Howlett pgoff, vm_userfaultfd_ctx, anon_name)) { 946eef19944SJakub Matěna merge_prev = true; 94718b098afSLiam R. Howlett vma_prev(vmi); 9481da177e4SLinus Torvalds } 9490503ea8fSLiam R. Howlett } 950b0729ae0SLorenzo Stoakes 951eef19944SJakub Matěna /* Can we merge the successor? */ 95200cd00a6SLorenzo Stoakes if (next && mpol_equal(policy, vma_policy(next)) && 9530173db4fSLorenzo Stoakes can_vma_merge_before(next, vm_flags, anon_vma, file, pgoff+pglen, 9549a10064fSColin Cross vm_userfaultfd_ctx, anon_name)) { 955eef19944SJakub Matěna merge_next = true; 956eef19944SJakub Matěna } 9570503ea8fSLiam R. Howlett 9580173db4fSLorenzo Stoakes if (!merge_prev && !merge_next) 9590173db4fSLorenzo Stoakes return NULL; /* Not mergeable. */ 9600173db4fSLorenzo Stoakes 9610173db4fSLorenzo Stoakes res = vma = prev; 9620503ea8fSLiam R. Howlett remove = remove2 = adjust = NULL; 9630173db4fSLorenzo Stoakes 9640173db4fSLorenzo Stoakes /* Verify some invariant that must be enforced by the caller. */ 9650173db4fSLorenzo Stoakes VM_WARN_ON(prev && addr <= prev->vm_start); 9660173db4fSLorenzo Stoakes VM_WARN_ON(curr && (addr != curr->vm_start || end > curr->vm_end)); 9670173db4fSLorenzo Stoakes VM_WARN_ON(addr >= end); 9680173db4fSLorenzo Stoakes 969eef19944SJakub Matěna /* Can we merge both the predecessor and the successor? */ 970eef19944SJakub Matěna if (merge_prev && merge_next && 9710503ea8fSLiam R. Howlett is_mergeable_anon_vma(prev->anon_vma, next->anon_vma, NULL)) { 9725ff783f1SVlastimil Babka remove = next; /* case 1 */ 9730503ea8fSLiam R. Howlett vma_end = next->vm_end; 97450dac011SVlastimil Babka err = dup_anon_vma(prev, next); 975fcfccd91SLorenzo Stoakes if (curr) { /* case 6 */ 976fcfccd91SLorenzo Stoakes remove = curr; 9775ff783f1SVlastimil Babka remove2 = next; 9785ff783f1SVlastimil Babka if (!next->anon_vma) 979fcfccd91SLorenzo Stoakes err = dup_anon_vma(prev, curr); 9800503ea8fSLiam R. Howlett } 9810173db4fSLorenzo Stoakes } else if (merge_prev) { /* case 2 */ 982fcfccd91SLorenzo Stoakes if (curr) { 983fcfccd91SLorenzo Stoakes err = dup_anon_vma(prev, curr); 984fcfccd91SLorenzo Stoakes if (end == curr->vm_end) { /* case 7 */ 985fcfccd91SLorenzo Stoakes remove = curr; 9860503ea8fSLiam R. Howlett } else { /* case 5 */ 987fcfccd91SLorenzo Stoakes adjust = curr; 988fcfccd91SLorenzo Stoakes adj_start = (end - curr->vm_start); 9890503ea8fSLiam R. Howlett } 9900503ea8fSLiam R. Howlett } 9910173db4fSLorenzo Stoakes } else { /* merge_next */ 992eef19944SJakub Matěna res = next; 9930503ea8fSLiam R. Howlett if (prev && addr < prev->vm_end) { /* case 4 */ 9940503ea8fSLiam R. Howlett vma_end = addr; 995183b7a60SVlastimil Babka adjust = next; 9961e76454fSVlastimil Babka adj_start = -(prev->vm_end - addr); 997183b7a60SVlastimil Babka err = dup_anon_vma(next, prev); 9980503ea8fSLiam R. Howlett } else { 999b0729ae0SLorenzo Stoakes /* 1000b0729ae0SLorenzo Stoakes * Note that cases 3 and 8 are the ONLY ones where prev 1001b0729ae0SLorenzo Stoakes * is permitted to be (but is not necessarily) NULL. 1002b0729ae0SLorenzo Stoakes */ 10030503ea8fSLiam R. Howlett vma = next; /* case 3 */ 10040503ea8fSLiam R. Howlett vma_start = addr; 10050503ea8fSLiam R. Howlett vma_end = next->vm_end; 1006097d70c6SVlastimil Babka vma_pgoff = next->vm_pgoff; 1007fcfccd91SLorenzo Stoakes if (curr) { /* case 8 */ 1008fcfccd91SLorenzo Stoakes vma_pgoff = curr->vm_pgoff; 1009fcfccd91SLorenzo Stoakes remove = curr; 1010fcfccd91SLorenzo Stoakes err = dup_anon_vma(next, curr); 10110503ea8fSLiam R. Howlett } 10120503ea8fSLiam R. Howlett } 10131da177e4SLinus Torvalds } 10141da177e4SLinus Torvalds 10150173db4fSLorenzo Stoakes /* Error in anon_vma clone. */ 1016eef19944SJakub Matěna if (err) 10171da177e4SLinus Torvalds return NULL; 10180503ea8fSLiam R. Howlett 10190503ea8fSLiam R. Howlett if (vma_iter_prealloc(vmi)) 10200503ea8fSLiam R. Howlett return NULL; 10210503ea8fSLiam R. Howlett 10220503ea8fSLiam R. Howlett init_multi_vma_prep(&vp, vma, adjust, remove, remove2); 10230503ea8fSLiam R. Howlett VM_WARN_ON(vp.anon_vma && adjust && adjust->anon_vma && 10240503ea8fSLiam R. Howlett vp.anon_vma != adjust->anon_vma); 10250503ea8fSLiam R. Howlett 10260503ea8fSLiam R. Howlett vma_prepare(&vp); 1027ccf1d78dSSuren Baghdasaryan vma_adjust_trans_huge(vma, vma_start, vma_end, adj_start); 10280503ea8fSLiam R. Howlett if (vma_start < vma->vm_start || vma_end > vma->vm_end) 10290503ea8fSLiam R. Howlett vma_expanded = true; 10300503ea8fSLiam R. Howlett 10310503ea8fSLiam R. Howlett vma->vm_start = vma_start; 10320503ea8fSLiam R. Howlett vma->vm_end = vma_end; 10330503ea8fSLiam R. Howlett vma->vm_pgoff = vma_pgoff; 10340503ea8fSLiam R. Howlett 10350503ea8fSLiam R. Howlett if (vma_expanded) 10360503ea8fSLiam R. Howlett vma_iter_store(vmi, vma); 10370503ea8fSLiam R. Howlett 10381e76454fSVlastimil Babka if (adj_start) { 10391e76454fSVlastimil Babka adjust->vm_start += adj_start; 10401e76454fSVlastimil Babka adjust->vm_pgoff += adj_start >> PAGE_SHIFT; 10411e76454fSVlastimil Babka if (adj_start < 0) { 10420503ea8fSLiam R. Howlett WARN_ON(vma_expanded); 10430503ea8fSLiam R. Howlett vma_iter_store(vmi, next); 10440503ea8fSLiam R. Howlett } 10450503ea8fSLiam R. Howlett } 10460503ea8fSLiam R. Howlett 10470503ea8fSLiam R. Howlett vma_complete(&vp, vmi, mm); 10480503ea8fSLiam R. Howlett vma_iter_free(vmi); 10490503ea8fSLiam R. Howlett validate_mm(mm); 1050eef19944SJakub Matěna khugepaged_enter_vma(res, vm_flags); 10511da177e4SLinus Torvalds 10529760ebffSLiam R. Howlett return res; 1053f2ebfe43SLiam R. Howlett } 1054f2ebfe43SLiam R. Howlett 10551da177e4SLinus Torvalds /* 1056b4f315b4SEthon Paul * Rough compatibility check to quickly see if it's even worth looking 1057d0e9fe17SLinus Torvalds * at sharing an anon_vma. 1058d0e9fe17SLinus Torvalds * 1059d0e9fe17SLinus Torvalds * They need to have the same vm_file, and the flags can only differ 1060d0e9fe17SLinus Torvalds * in things that mprotect may change. 1061d0e9fe17SLinus Torvalds * 1062d0e9fe17SLinus Torvalds * NOTE! The fact that we share an anon_vma doesn't _have_ to mean that 1063d0e9fe17SLinus Torvalds * we can merge the two vma's. For example, we refuse to merge a vma if 1064d0e9fe17SLinus Torvalds * there is a vm_ops->close() function, because that indicates that the 1065d0e9fe17SLinus Torvalds * driver is doing some kind of reference counting. But that doesn't 1066d0e9fe17SLinus Torvalds * really matter for the anon_vma sharing case. 1067d0e9fe17SLinus Torvalds */ 1068d0e9fe17SLinus Torvalds static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *b) 1069d0e9fe17SLinus Torvalds { 1070d0e9fe17SLinus Torvalds return a->vm_end == b->vm_start && 1071d0e9fe17SLinus Torvalds mpol_equal(vma_policy(a), vma_policy(b)) && 1072d0e9fe17SLinus Torvalds a->vm_file == b->vm_file && 10736cb4d9a2SAnshuman Khandual !((a->vm_flags ^ b->vm_flags) & ~(VM_ACCESS_FLAGS | VM_SOFTDIRTY)) && 1074d0e9fe17SLinus Torvalds b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT); 1075d0e9fe17SLinus Torvalds } 1076d0e9fe17SLinus Torvalds 1077d0e9fe17SLinus Torvalds /* 1078d0e9fe17SLinus Torvalds * Do some basic sanity checking to see if we can re-use the anon_vma 1079d0e9fe17SLinus Torvalds * from 'old'. The 'a'/'b' vma's are in VM order - one of them will be 1080d0e9fe17SLinus Torvalds * the same as 'old', the other will be the new one that is trying 1081d0e9fe17SLinus Torvalds * to share the anon_vma. 1082d0e9fe17SLinus Torvalds * 10835b449489SFlorian Rommel * NOTE! This runs with mmap_lock held for reading, so it is possible that 1084d0e9fe17SLinus Torvalds * the anon_vma of 'old' is concurrently in the process of being set up 1085d0e9fe17SLinus Torvalds * by another page fault trying to merge _that_. But that's ok: if it 1086d0e9fe17SLinus Torvalds * is being set up, that automatically means that it will be a singleton 1087d0e9fe17SLinus Torvalds * acceptable for merging, so we can do all of this optimistically. But 10884db0c3c2SJason Low * we do that READ_ONCE() to make sure that we never re-load the pointer. 1089d0e9fe17SLinus Torvalds * 1090d0e9fe17SLinus Torvalds * IOW: that the "list_is_singular()" test on the anon_vma_chain only 1091d0e9fe17SLinus Torvalds * matters for the 'stable anon_vma' case (ie the thing we want to avoid 1092d0e9fe17SLinus Torvalds * is to return an anon_vma that is "complex" due to having gone through 1093d0e9fe17SLinus Torvalds * a fork). 1094d0e9fe17SLinus Torvalds * 1095d0e9fe17SLinus Torvalds * We also make sure that the two vma's are compatible (adjacent, 1096d0e9fe17SLinus Torvalds * and with the same memory policies). That's all stable, even with just 10975b449489SFlorian Rommel * a read lock on the mmap_lock. 1098d0e9fe17SLinus Torvalds */ 1099d0e9fe17SLinus Torvalds static struct anon_vma *reusable_anon_vma(struct vm_area_struct *old, struct vm_area_struct *a, struct vm_area_struct *b) 1100d0e9fe17SLinus Torvalds { 1101d0e9fe17SLinus Torvalds if (anon_vma_compatible(a, b)) { 11024db0c3c2SJason Low struct anon_vma *anon_vma = READ_ONCE(old->anon_vma); 1103d0e9fe17SLinus Torvalds 1104d0e9fe17SLinus Torvalds if (anon_vma && list_is_singular(&old->anon_vma_chain)) 1105d0e9fe17SLinus Torvalds return anon_vma; 1106d0e9fe17SLinus Torvalds } 1107d0e9fe17SLinus Torvalds return NULL; 1108d0e9fe17SLinus Torvalds } 1109d0e9fe17SLinus Torvalds 1110d0e9fe17SLinus Torvalds /* 11111da177e4SLinus Torvalds * find_mergeable_anon_vma is used by anon_vma_prepare, to check 11121da177e4SLinus Torvalds * neighbouring vmas for a suitable anon_vma, before it goes off 11131da177e4SLinus Torvalds * to allocate a new anon_vma. It checks because a repetitive 11141da177e4SLinus Torvalds * sequence of mprotects and faults may otherwise lead to distinct 11151da177e4SLinus Torvalds * anon_vmas being allocated, preventing vma merge in subsequent 11161da177e4SLinus Torvalds * mprotect. 11171da177e4SLinus Torvalds */ 11181da177e4SLinus Torvalds struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma) 11191da177e4SLinus Torvalds { 1120763ecb03SLiam R. Howlett MA_STATE(mas, &vma->vm_mm->mm_mt, vma->vm_end, vma->vm_end); 1121a67c8caaSMiaohe Lin struct anon_vma *anon_vma = NULL; 1122763ecb03SLiam R. Howlett struct vm_area_struct *prev, *next; 11231da177e4SLinus Torvalds 1124a67c8caaSMiaohe Lin /* Try next first. */ 1125763ecb03SLiam R. Howlett next = mas_walk(&mas); 1126763ecb03SLiam R. Howlett if (next) { 1127763ecb03SLiam R. Howlett anon_vma = reusable_anon_vma(next, vma, next); 1128d0e9fe17SLinus Torvalds if (anon_vma) 1129d0e9fe17SLinus Torvalds return anon_vma; 1130a67c8caaSMiaohe Lin } 11311da177e4SLinus Torvalds 1132763ecb03SLiam R. Howlett prev = mas_prev(&mas, 0); 1133763ecb03SLiam R. Howlett VM_BUG_ON_VMA(prev != vma, vma); 1134763ecb03SLiam R. Howlett prev = mas_prev(&mas, 0); 1135a67c8caaSMiaohe Lin /* Try prev next. */ 1136763ecb03SLiam R. Howlett if (prev) 1137763ecb03SLiam R. Howlett anon_vma = reusable_anon_vma(prev, prev, vma); 1138a67c8caaSMiaohe Lin 11391da177e4SLinus Torvalds /* 1140a67c8caaSMiaohe Lin * We might reach here with anon_vma == NULL if we can't find 1141a67c8caaSMiaohe Lin * any reusable anon_vma. 11421da177e4SLinus Torvalds * There's no absolute need to look only at touching neighbours: 11431da177e4SLinus Torvalds * we could search further afield for "compatible" anon_vmas. 11441da177e4SLinus Torvalds * But it would probably just be a waste of time searching, 11451da177e4SLinus Torvalds * or lead to too many vmas hanging off the same anon_vma. 11461da177e4SLinus Torvalds * We're trying to allow mprotect remerging later on, 11471da177e4SLinus Torvalds * not trying to minimize memory used for anon_vmas. 11481da177e4SLinus Torvalds */ 1149a67c8caaSMiaohe Lin return anon_vma; 11501da177e4SLinus Torvalds } 11511da177e4SLinus Torvalds 11521da177e4SLinus Torvalds /* 115340401530SAl Viro * If a hint addr is less than mmap_min_addr change hint to be as 115440401530SAl Viro * low as possible but still greater than mmap_min_addr 115540401530SAl Viro */ 115640401530SAl Viro static inline unsigned long round_hint_to_min(unsigned long hint) 115740401530SAl Viro { 115840401530SAl Viro hint &= PAGE_MASK; 115940401530SAl Viro if (((void *)hint != NULL) && 116040401530SAl Viro (hint < mmap_min_addr)) 116140401530SAl Viro return PAGE_ALIGN(mmap_min_addr); 116240401530SAl Viro return hint; 116340401530SAl Viro } 116440401530SAl Viro 11656aeb2542SMike Rapoport int mlock_future_check(struct mm_struct *mm, unsigned long flags, 1166363ee17fSDavidlohr Bueso unsigned long len) 1167363ee17fSDavidlohr Bueso { 1168363ee17fSDavidlohr Bueso unsigned long locked, lock_limit; 1169363ee17fSDavidlohr Bueso 1170363ee17fSDavidlohr Bueso /* mlock MCL_FUTURE? */ 1171363ee17fSDavidlohr Bueso if (flags & VM_LOCKED) { 1172363ee17fSDavidlohr Bueso locked = len >> PAGE_SHIFT; 1173363ee17fSDavidlohr Bueso locked += mm->locked_vm; 1174363ee17fSDavidlohr Bueso lock_limit = rlimit(RLIMIT_MEMLOCK); 1175363ee17fSDavidlohr Bueso lock_limit >>= PAGE_SHIFT; 1176363ee17fSDavidlohr Bueso if (locked > lock_limit && !capable(CAP_IPC_LOCK)) 1177363ee17fSDavidlohr Bueso return -EAGAIN; 1178363ee17fSDavidlohr Bueso } 1179363ee17fSDavidlohr Bueso return 0; 1180363ee17fSDavidlohr Bueso } 1181363ee17fSDavidlohr Bueso 1182be83bbf8SLinus Torvalds static inline u64 file_mmap_size_max(struct file *file, struct inode *inode) 1183be83bbf8SLinus Torvalds { 1184be83bbf8SLinus Torvalds if (S_ISREG(inode->i_mode)) 1185423913adSLinus Torvalds return MAX_LFS_FILESIZE; 1186be83bbf8SLinus Torvalds 1187be83bbf8SLinus Torvalds if (S_ISBLK(inode->i_mode)) 1188be83bbf8SLinus Torvalds return MAX_LFS_FILESIZE; 1189be83bbf8SLinus Torvalds 119076f34950SIvan Khoronzhuk if (S_ISSOCK(inode->i_mode)) 119176f34950SIvan Khoronzhuk return MAX_LFS_FILESIZE; 119276f34950SIvan Khoronzhuk 1193be83bbf8SLinus Torvalds /* Special "we do even unsigned file positions" case */ 1194be83bbf8SLinus Torvalds if (file->f_mode & FMODE_UNSIGNED_OFFSET) 1195be83bbf8SLinus Torvalds return 0; 1196be83bbf8SLinus Torvalds 1197be83bbf8SLinus Torvalds /* Yes, random drivers might want more. But I'm tired of buggy drivers */ 1198be83bbf8SLinus Torvalds return ULONG_MAX; 1199be83bbf8SLinus Torvalds } 1200be83bbf8SLinus Torvalds 1201be83bbf8SLinus Torvalds static inline bool file_mmap_ok(struct file *file, struct inode *inode, 1202be83bbf8SLinus Torvalds unsigned long pgoff, unsigned long len) 1203be83bbf8SLinus Torvalds { 1204be83bbf8SLinus Torvalds u64 maxsize = file_mmap_size_max(file, inode); 1205be83bbf8SLinus Torvalds 1206be83bbf8SLinus Torvalds if (maxsize && len > maxsize) 1207be83bbf8SLinus Torvalds return false; 1208be83bbf8SLinus Torvalds maxsize -= len; 1209be83bbf8SLinus Torvalds if (pgoff > maxsize >> PAGE_SHIFT) 1210be83bbf8SLinus Torvalds return false; 1211be83bbf8SLinus Torvalds return true; 1212be83bbf8SLinus Torvalds } 1213be83bbf8SLinus Torvalds 121440401530SAl Viro /* 12153e4e28c5SMichel Lespinasse * The caller must write-lock current->mm->mmap_lock. 12161da177e4SLinus Torvalds */ 12171fcfd8dbSOleg Nesterov unsigned long do_mmap(struct file *file, unsigned long addr, 12181da177e4SLinus Torvalds unsigned long len, unsigned long prot, 121945e55300SPeter Collingbourne unsigned long flags, unsigned long pgoff, 122045e55300SPeter Collingbourne unsigned long *populate, struct list_head *uf) 12211da177e4SLinus Torvalds { 12221da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 122345e55300SPeter Collingbourne vm_flags_t vm_flags; 122462b5f7d0SDave Hansen int pkey = 0; 12251da177e4SLinus Torvalds 1226524e00b3SLiam R. Howlett validate_mm(mm); 122741badc15SMichel Lespinasse *populate = 0; 1228bebeb3d6SMichel Lespinasse 1229e37609bbSPiotr Kwapulinski if (!len) 1230e37609bbSPiotr Kwapulinski return -EINVAL; 1231e37609bbSPiotr Kwapulinski 12321da177e4SLinus Torvalds /* 12331da177e4SLinus Torvalds * Does the application expect PROT_READ to imply PROT_EXEC? 12341da177e4SLinus Torvalds * 12351da177e4SLinus Torvalds * (the exception is when the underlying filesystem is noexec 12361da177e4SLinus Torvalds * mounted, in which case we dont add PROT_EXEC.) 12371da177e4SLinus Torvalds */ 12381da177e4SLinus Torvalds if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) 123990f8572bSEric W. Biederman if (!(file && path_noexec(&file->f_path))) 12401da177e4SLinus Torvalds prot |= PROT_EXEC; 12411da177e4SLinus Torvalds 1242a4ff8e86SMichal Hocko /* force arch specific MAP_FIXED handling in get_unmapped_area */ 1243a4ff8e86SMichal Hocko if (flags & MAP_FIXED_NOREPLACE) 1244a4ff8e86SMichal Hocko flags |= MAP_FIXED; 1245a4ff8e86SMichal Hocko 12467cd94146SEric Paris if (!(flags & MAP_FIXED)) 12477cd94146SEric Paris addr = round_hint_to_min(addr); 12487cd94146SEric Paris 12491da177e4SLinus Torvalds /* Careful about overflows.. */ 12501da177e4SLinus Torvalds len = PAGE_ALIGN(len); 12519206de95SAl Viro if (!len) 12521da177e4SLinus Torvalds return -ENOMEM; 12531da177e4SLinus Torvalds 12541da177e4SLinus Torvalds /* offset overflow? */ 12551da177e4SLinus Torvalds if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) 12561da177e4SLinus Torvalds return -EOVERFLOW; 12571da177e4SLinus Torvalds 12581da177e4SLinus Torvalds /* Too many mappings? */ 12591da177e4SLinus Torvalds if (mm->map_count > sysctl_max_map_count) 12601da177e4SLinus Torvalds return -ENOMEM; 12611da177e4SLinus Torvalds 12621da177e4SLinus Torvalds /* Obtain the address to map to. we verify (or select) it and ensure 12631da177e4SLinus Torvalds * that it represents a valid section of the address space. 12641da177e4SLinus Torvalds */ 12651da177e4SLinus Torvalds addr = get_unmapped_area(file, addr, len, pgoff, flags); 1266ff68dac6SGaowei Pu if (IS_ERR_VALUE(addr)) 12671da177e4SLinus Torvalds return addr; 12681da177e4SLinus Torvalds 1269a4ff8e86SMichal Hocko if (flags & MAP_FIXED_NOREPLACE) { 127035e43c5fSLiam Howlett if (find_vma_intersection(mm, addr, addr + len)) 1271a4ff8e86SMichal Hocko return -EEXIST; 1272a4ff8e86SMichal Hocko } 1273a4ff8e86SMichal Hocko 127462b5f7d0SDave Hansen if (prot == PROT_EXEC) { 127562b5f7d0SDave Hansen pkey = execute_only_pkey(mm); 127662b5f7d0SDave Hansen if (pkey < 0) 127762b5f7d0SDave Hansen pkey = 0; 127862b5f7d0SDave Hansen } 127962b5f7d0SDave Hansen 12801da177e4SLinus Torvalds /* Do simple checking here so the lower-level routines won't have 12811da177e4SLinus Torvalds * to. we assume access permissions have been handled by the open 12821da177e4SLinus Torvalds * of the memory object, so we don't do any here. 12831da177e4SLinus Torvalds */ 128445e55300SPeter Collingbourne vm_flags = calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) | 12851da177e4SLinus Torvalds mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; 12861da177e4SLinus Torvalds 1287cdf7b341SHuang Shijie if (flags & MAP_LOCKED) 12881da177e4SLinus Torvalds if (!can_do_mlock()) 12891da177e4SLinus Torvalds return -EPERM; 1290ba470de4SRik van Riel 1291363ee17fSDavidlohr Bueso if (mlock_future_check(mm, vm_flags, len)) 12921da177e4SLinus Torvalds return -EAGAIN; 12931da177e4SLinus Torvalds 12941da177e4SLinus Torvalds if (file) { 1295077bf22bSOleg Nesterov struct inode *inode = file_inode(file); 12961c972597SDan Williams unsigned long flags_mask; 12971c972597SDan Williams 1298be83bbf8SLinus Torvalds if (!file_mmap_ok(file, inode, pgoff, len)) 1299be83bbf8SLinus Torvalds return -EOVERFLOW; 1300be83bbf8SLinus Torvalds 13011c972597SDan Williams flags_mask = LEGACY_MAP_MASK | file->f_op->mmap_supported_flags; 1302077bf22bSOleg Nesterov 13031da177e4SLinus Torvalds switch (flags & MAP_TYPE) { 13041da177e4SLinus Torvalds case MAP_SHARED: 13051c972597SDan Williams /* 13061c972597SDan Williams * Force use of MAP_SHARED_VALIDATE with non-legacy 13071c972597SDan Williams * flags. E.g. MAP_SYNC is dangerous to use with 13081c972597SDan Williams * MAP_SHARED as you don't know which consistency model 13091c972597SDan Williams * you will get. We silently ignore unsupported flags 13101c972597SDan Williams * with MAP_SHARED to preserve backward compatibility. 13111c972597SDan Williams */ 13121c972597SDan Williams flags &= LEGACY_MAP_MASK; 1313e4a9bc58SJoe Perches fallthrough; 13141c972597SDan Williams case MAP_SHARED_VALIDATE: 13151c972597SDan Williams if (flags & ~flags_mask) 13161c972597SDan Williams return -EOPNOTSUPP; 1317dc617f29SDarrick J. Wong if (prot & PROT_WRITE) { 1318dc617f29SDarrick J. Wong if (!(file->f_mode & FMODE_WRITE)) 13191da177e4SLinus Torvalds return -EACCES; 1320dc617f29SDarrick J. Wong if (IS_SWAPFILE(file->f_mapping->host)) 1321dc617f29SDarrick J. Wong return -ETXTBSY; 1322dc617f29SDarrick J. Wong } 13231da177e4SLinus Torvalds 13241da177e4SLinus Torvalds /* 13251da177e4SLinus Torvalds * Make sure we don't allow writing to an append-only 13261da177e4SLinus Torvalds * file.. 13271da177e4SLinus Torvalds */ 13281da177e4SLinus Torvalds if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE)) 13291da177e4SLinus Torvalds return -EACCES; 13301da177e4SLinus Torvalds 13311da177e4SLinus Torvalds vm_flags |= VM_SHARED | VM_MAYSHARE; 13321da177e4SLinus Torvalds if (!(file->f_mode & FMODE_WRITE)) 13331da177e4SLinus Torvalds vm_flags &= ~(VM_MAYWRITE | VM_SHARED); 1334e4a9bc58SJoe Perches fallthrough; 13351da177e4SLinus Torvalds case MAP_PRIVATE: 13361da177e4SLinus Torvalds if (!(file->f_mode & FMODE_READ)) 13371da177e4SLinus Torvalds return -EACCES; 133890f8572bSEric W. Biederman if (path_noexec(&file->f_path)) { 133980c5606cSLinus Torvalds if (vm_flags & VM_EXEC) 134080c5606cSLinus Torvalds return -EPERM; 134180c5606cSLinus Torvalds vm_flags &= ~VM_MAYEXEC; 134280c5606cSLinus Torvalds } 134380c5606cSLinus Torvalds 134472c2d531SAl Viro if (!file->f_op->mmap) 134580c5606cSLinus Torvalds return -ENODEV; 1346b2c56e4fSOleg Nesterov if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) 1347b2c56e4fSOleg Nesterov return -EINVAL; 13481da177e4SLinus Torvalds break; 13491da177e4SLinus Torvalds 13501da177e4SLinus Torvalds default: 13511da177e4SLinus Torvalds return -EINVAL; 13521da177e4SLinus Torvalds } 13531da177e4SLinus Torvalds } else { 13541da177e4SLinus Torvalds switch (flags & MAP_TYPE) { 13551da177e4SLinus Torvalds case MAP_SHARED: 1356b2c56e4fSOleg Nesterov if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) 1357b2c56e4fSOleg Nesterov return -EINVAL; 1358ce363942STejun Heo /* 1359ce363942STejun Heo * Ignore pgoff. 1360ce363942STejun Heo */ 1361ce363942STejun Heo pgoff = 0; 13621da177e4SLinus Torvalds vm_flags |= VM_SHARED | VM_MAYSHARE; 13631da177e4SLinus Torvalds break; 13641da177e4SLinus Torvalds case MAP_PRIVATE: 13651da177e4SLinus Torvalds /* 13661da177e4SLinus Torvalds * Set pgoff according to addr for anon_vma. 13671da177e4SLinus Torvalds */ 13681da177e4SLinus Torvalds pgoff = addr >> PAGE_SHIFT; 13691da177e4SLinus Torvalds break; 13701da177e4SLinus Torvalds default: 13711da177e4SLinus Torvalds return -EINVAL; 13721da177e4SLinus Torvalds } 13731da177e4SLinus Torvalds } 13741da177e4SLinus Torvalds 1375c22c0d63SMichel Lespinasse /* 1376c22c0d63SMichel Lespinasse * Set 'VM_NORESERVE' if we should not account for the 1377c22c0d63SMichel Lespinasse * memory use of this mapping. 1378c22c0d63SMichel Lespinasse */ 1379c22c0d63SMichel Lespinasse if (flags & MAP_NORESERVE) { 1380c22c0d63SMichel Lespinasse /* We honor MAP_NORESERVE if allowed to overcommit */ 1381c22c0d63SMichel Lespinasse if (sysctl_overcommit_memory != OVERCOMMIT_NEVER) 1382c22c0d63SMichel Lespinasse vm_flags |= VM_NORESERVE; 1383c22c0d63SMichel Lespinasse 1384c22c0d63SMichel Lespinasse /* hugetlb applies strict overcommit unless MAP_NORESERVE */ 1385c22c0d63SMichel Lespinasse if (file && is_file_hugepages(file)) 1386c22c0d63SMichel Lespinasse vm_flags |= VM_NORESERVE; 1387c22c0d63SMichel Lespinasse } 1388c22c0d63SMichel Lespinasse 1389897ab3e0SMike Rapoport addr = mmap_region(file, addr, len, vm_flags, pgoff, uf); 139009a9f1d2SMichel Lespinasse if (!IS_ERR_VALUE(addr) && 139109a9f1d2SMichel Lespinasse ((vm_flags & VM_LOCKED) || 139209a9f1d2SMichel Lespinasse (flags & (MAP_POPULATE | MAP_NONBLOCK)) == MAP_POPULATE)) 139341badc15SMichel Lespinasse *populate = len; 1394bebeb3d6SMichel Lespinasse return addr; 13950165ab44SMiklos Szeredi } 13966be5ceb0SLinus Torvalds 1397a90f590aSDominik Brodowski unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len, 1398a90f590aSDominik Brodowski unsigned long prot, unsigned long flags, 1399a90f590aSDominik Brodowski unsigned long fd, unsigned long pgoff) 140066f0dc48SHugh Dickins { 140166f0dc48SHugh Dickins struct file *file = NULL; 14021e3ee14bSChen Gang unsigned long retval; 140366f0dc48SHugh Dickins 140466f0dc48SHugh Dickins if (!(flags & MAP_ANONYMOUS)) { 1405120a795dSAl Viro audit_mmap_fd(fd, flags); 140666f0dc48SHugh Dickins file = fget(fd); 140766f0dc48SHugh Dickins if (!file) 14081e3ee14bSChen Gang return -EBADF; 14097bba8f0eSZhen Lei if (is_file_hugepages(file)) { 1410af73e4d9SNaoya Horiguchi len = ALIGN(len, huge_page_size(hstate_file(file))); 14117bba8f0eSZhen Lei } else if (unlikely(flags & MAP_HUGETLB)) { 1412493af578SJörn Engel retval = -EINVAL; 1413493af578SJörn Engel goto out_fput; 14147bba8f0eSZhen Lei } 141566f0dc48SHugh Dickins } else if (flags & MAP_HUGETLB) { 1416c103a4dcSAndrew Morton struct hstate *hs; 1417af73e4d9SNaoya Horiguchi 141820ac2893SAnshuman Khandual hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); 1419091d0d55SLi Zefan if (!hs) 1420091d0d55SLi Zefan return -EINVAL; 1421091d0d55SLi Zefan 1422091d0d55SLi Zefan len = ALIGN(len, huge_page_size(hs)); 142366f0dc48SHugh Dickins /* 142466f0dc48SHugh Dickins * VM_NORESERVE is used because the reservations will be 142566f0dc48SHugh Dickins * taken when vm_ops->mmap() is called 142666f0dc48SHugh Dickins */ 1427af73e4d9SNaoya Horiguchi file = hugetlb_file_setup(HUGETLB_ANON_FILE, len, 142842d7395fSAndi Kleen VM_NORESERVE, 142983c1fd76Szhangyiru HUGETLB_ANONHUGE_INODE, 143042d7395fSAndi Kleen (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); 143166f0dc48SHugh Dickins if (IS_ERR(file)) 143266f0dc48SHugh Dickins return PTR_ERR(file); 143366f0dc48SHugh Dickins } 143466f0dc48SHugh Dickins 14359fbeb5abSMichal Hocko retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff); 1436493af578SJörn Engel out_fput: 143766f0dc48SHugh Dickins if (file) 143866f0dc48SHugh Dickins fput(file); 143966f0dc48SHugh Dickins return retval; 144066f0dc48SHugh Dickins } 144166f0dc48SHugh Dickins 1442a90f590aSDominik Brodowski SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, 1443a90f590aSDominik Brodowski unsigned long, prot, unsigned long, flags, 1444a90f590aSDominik Brodowski unsigned long, fd, unsigned long, pgoff) 1445a90f590aSDominik Brodowski { 1446a90f590aSDominik Brodowski return ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff); 1447a90f590aSDominik Brodowski } 1448a90f590aSDominik Brodowski 1449a4679373SChristoph Hellwig #ifdef __ARCH_WANT_SYS_OLD_MMAP 1450a4679373SChristoph Hellwig struct mmap_arg_struct { 1451a4679373SChristoph Hellwig unsigned long addr; 1452a4679373SChristoph Hellwig unsigned long len; 1453a4679373SChristoph Hellwig unsigned long prot; 1454a4679373SChristoph Hellwig unsigned long flags; 1455a4679373SChristoph Hellwig unsigned long fd; 1456a4679373SChristoph Hellwig unsigned long offset; 1457a4679373SChristoph Hellwig }; 1458a4679373SChristoph Hellwig 1459a4679373SChristoph Hellwig SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg) 1460a4679373SChristoph Hellwig { 1461a4679373SChristoph Hellwig struct mmap_arg_struct a; 1462a4679373SChristoph Hellwig 1463a4679373SChristoph Hellwig if (copy_from_user(&a, arg, sizeof(a))) 1464a4679373SChristoph Hellwig return -EFAULT; 1465de1741a1SAlexander Kuleshov if (offset_in_page(a.offset)) 1466a4679373SChristoph Hellwig return -EINVAL; 1467a4679373SChristoph Hellwig 1468a90f590aSDominik Brodowski return ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, 1469a4679373SChristoph Hellwig a.offset >> PAGE_SHIFT); 1470a4679373SChristoph Hellwig } 1471a4679373SChristoph Hellwig #endif /* __ARCH_WANT_SYS_OLD_MMAP */ 1472a4679373SChristoph Hellwig 14734e950f6fSAlexey Dobriyan /* 14748bb4e7a2SWei Yang * Some shared mappings will want the pages marked read-only 14754e950f6fSAlexey Dobriyan * to track write events. If so, we'll downgrade vm_page_prot 14764e950f6fSAlexey Dobriyan * to the private version (using protection_map[] without the 14774e950f6fSAlexey Dobriyan * VM_SHARED bit). 14784e950f6fSAlexey Dobriyan */ 14796d2329f8SAndrea Arcangeli int vma_wants_writenotify(struct vm_area_struct *vma, pgprot_t vm_page_prot) 14804e950f6fSAlexey Dobriyan { 1481ca16d140SKOSAKI Motohiro vm_flags_t vm_flags = vma->vm_flags; 14828a04446aSKirill A. Shutemov const struct vm_operations_struct *vm_ops = vma->vm_ops; 14834e950f6fSAlexey Dobriyan 14844e950f6fSAlexey Dobriyan /* If it was private or non-writable, the write bit is already clear */ 14854e950f6fSAlexey Dobriyan if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED))) 14864e950f6fSAlexey Dobriyan return 0; 14874e950f6fSAlexey Dobriyan 14884e950f6fSAlexey Dobriyan /* The backer wishes to know when pages are first written to? */ 14898a04446aSKirill A. Shutemov if (vm_ops && (vm_ops->page_mkwrite || vm_ops->pfn_mkwrite)) 14904e950f6fSAlexey Dobriyan return 1; 14914e950f6fSAlexey Dobriyan 149264e45507SPeter Feiner /* The open routine did something to the protections that pgprot_modify 149364e45507SPeter Feiner * won't preserve? */ 14946d2329f8SAndrea Arcangeli if (pgprot_val(vm_page_prot) != 14956d2329f8SAndrea Arcangeli pgprot_val(vm_pgprot_modify(vm_page_prot, vm_flags))) 14964e950f6fSAlexey Dobriyan return 0; 14974e950f6fSAlexey Dobriyan 1498f96f7a40SDavid Hildenbrand /* 1499f96f7a40SDavid Hildenbrand * Do we need to track softdirty? hugetlb does not support softdirty 1500f96f7a40SDavid Hildenbrand * tracking yet. 1501f96f7a40SDavid Hildenbrand */ 1502f96f7a40SDavid Hildenbrand if (vma_soft_dirty_enabled(vma) && !is_vm_hugetlb_page(vma)) 150364e45507SPeter Feiner return 1; 150464e45507SPeter Feiner 150551d3d5ebSDavid Hildenbrand /* Do we need write faults for uffd-wp tracking? */ 150651d3d5ebSDavid Hildenbrand if (userfaultfd_wp(vma)) 150751d3d5ebSDavid Hildenbrand return 1; 150851d3d5ebSDavid Hildenbrand 15094e950f6fSAlexey Dobriyan /* Specialty mapping? */ 15104b6e1e37SKonstantin Khlebnikov if (vm_flags & VM_PFNMAP) 15114e950f6fSAlexey Dobriyan return 0; 15124e950f6fSAlexey Dobriyan 15134e950f6fSAlexey Dobriyan /* Can the mapping track the dirty pages? */ 15144e950f6fSAlexey Dobriyan return vma->vm_file && vma->vm_file->f_mapping && 1515f56753acSChristoph Hellwig mapping_can_writeback(vma->vm_file->f_mapping); 15164e950f6fSAlexey Dobriyan } 15174e950f6fSAlexey Dobriyan 1518fc8744adSLinus Torvalds /* 1519fc8744adSLinus Torvalds * We account for memory if it's a private writeable mapping, 15205a6fe125SMel Gorman * not hugepages and VM_NORESERVE wasn't set. 1521fc8744adSLinus Torvalds */ 1522ca16d140SKOSAKI Motohiro static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags) 1523fc8744adSLinus Torvalds { 15245a6fe125SMel Gorman /* 15255a6fe125SMel Gorman * hugetlb has its own accounting separate from the core VM 15265a6fe125SMel Gorman * VM_HUGETLB may not be set yet so we cannot check for that flag. 15275a6fe125SMel Gorman */ 15285a6fe125SMel Gorman if (file && is_file_hugepages(file)) 15295a6fe125SMel Gorman return 0; 15305a6fe125SMel Gorman 1531fc8744adSLinus Torvalds return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE; 1532fc8744adSLinus Torvalds } 1533fc8744adSLinus Torvalds 15343499a131SLiam R. Howlett /** 15353499a131SLiam R. Howlett * unmapped_area() - Find an area between the low_limit and the high_limit with 15363499a131SLiam R. Howlett * the correct alignment and offset, all from @info. Note: current->mm is used 15373499a131SLiam R. Howlett * for the search. 15383499a131SLiam R. Howlett * 153982b24936SVernon Yang * @info: The unmapped area information including the range [low_limit - 154082b24936SVernon Yang * high_limit), the alignment offset and mask. 15413499a131SLiam R. Howlett * 15423499a131SLiam R. Howlett * Return: A memory address or -ENOMEM. 15433499a131SLiam R. Howlett */ 1544baceaf1cSJaewon Kim static unsigned long unmapped_area(struct vm_unmapped_area_info *info) 1545db4fbfb9SMichel Lespinasse { 15463499a131SLiam R. Howlett unsigned long length, gap; 1547db4fbfb9SMichel Lespinasse 15483499a131SLiam R. Howlett MA_STATE(mas, ¤t->mm->mm_mt, 0, 0); 1549db4fbfb9SMichel Lespinasse 1550db4fbfb9SMichel Lespinasse /* Adjust search length to account for worst case alignment overhead */ 1551db4fbfb9SMichel Lespinasse length = info->length + info->align_mask; 1552db4fbfb9SMichel Lespinasse if (length < info->length) 1553db4fbfb9SMichel Lespinasse return -ENOMEM; 1554db4fbfb9SMichel Lespinasse 15553499a131SLiam R. Howlett if (mas_empty_area(&mas, info->low_limit, info->high_limit - 1, 15563499a131SLiam R. Howlett length)) 15573499a131SLiam R. Howlett return -ENOMEM; 15583499a131SLiam R. Howlett 1559d4af56c5SLiam R. Howlett gap = mas.index; 1560d4af56c5SLiam R. Howlett gap += (info->align_offset - gap) & info->align_mask; 15613499a131SLiam R. Howlett return gap; 1562db4fbfb9SMichel Lespinasse } 1563db4fbfb9SMichel Lespinasse 15643499a131SLiam R. Howlett /** 15653499a131SLiam R. Howlett * unmapped_area_topdown() - Find an area between the low_limit and the 156682b24936SVernon Yang * high_limit with the correct alignment and offset at the highest available 15673499a131SLiam R. Howlett * address, all from @info. Note: current->mm is used for the search. 15683499a131SLiam R. Howlett * 156982b24936SVernon Yang * @info: The unmapped area information including the range [low_limit - 157082b24936SVernon Yang * high_limit), the alignment offset and mask. 15713499a131SLiam R. Howlett * 15723499a131SLiam R. Howlett * Return: A memory address or -ENOMEM. 15733499a131SLiam R. Howlett */ 1574baceaf1cSJaewon Kim static unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info) 1575db4fbfb9SMichel Lespinasse { 15763499a131SLiam R. Howlett unsigned long length, gap; 1577d4af56c5SLiam R. Howlett 15783499a131SLiam R. Howlett MA_STATE(mas, ¤t->mm->mm_mt, 0, 0); 1579db4fbfb9SMichel Lespinasse /* Adjust search length to account for worst case alignment overhead */ 1580db4fbfb9SMichel Lespinasse length = info->length + info->align_mask; 1581db4fbfb9SMichel Lespinasse if (length < info->length) 1582db4fbfb9SMichel Lespinasse return -ENOMEM; 1583db4fbfb9SMichel Lespinasse 15843499a131SLiam R. Howlett if (mas_empty_area_rev(&mas, info->low_limit, info->high_limit - 1, 15853499a131SLiam R. Howlett length)) 15863499a131SLiam R. Howlett return -ENOMEM; 15873499a131SLiam R. Howlett 1588d4af56c5SLiam R. Howlett gap = mas.last + 1 - info->length; 1589d4af56c5SLiam R. Howlett gap -= (gap - info->align_offset) & info->align_mask; 15903499a131SLiam R. Howlett return gap; 1591db4fbfb9SMichel Lespinasse } 1592db4fbfb9SMichel Lespinasse 1593baceaf1cSJaewon Kim /* 1594baceaf1cSJaewon Kim * Search for an unmapped address range. 1595baceaf1cSJaewon Kim * 1596baceaf1cSJaewon Kim * We are looking for a range that: 1597baceaf1cSJaewon Kim * - does not intersect with any VMA; 1598baceaf1cSJaewon Kim * - is contained within the [low_limit, high_limit) interval; 1599baceaf1cSJaewon Kim * - is at least the desired size. 1600baceaf1cSJaewon Kim * - satisfies (begin_addr & align_mask) == (align_offset & align_mask) 1601baceaf1cSJaewon Kim */ 1602baceaf1cSJaewon Kim unsigned long vm_unmapped_area(struct vm_unmapped_area_info *info) 1603baceaf1cSJaewon Kim { 1604df529cabSJaewon Kim unsigned long addr; 1605df529cabSJaewon Kim 1606baceaf1cSJaewon Kim if (info->flags & VM_UNMAPPED_AREA_TOPDOWN) 1607df529cabSJaewon Kim addr = unmapped_area_topdown(info); 1608baceaf1cSJaewon Kim else 1609df529cabSJaewon Kim addr = unmapped_area(info); 1610df529cabSJaewon Kim 1611df529cabSJaewon Kim trace_vm_unmapped_area(addr, info); 1612df529cabSJaewon Kim return addr; 1613baceaf1cSJaewon Kim } 1614f6795053SSteve Capper 16151da177e4SLinus Torvalds /* Get an address range which is currently unmapped. 16161da177e4SLinus Torvalds * For shmat() with addr=0. 16171da177e4SLinus Torvalds * 16181da177e4SLinus Torvalds * Ugly calling convention alert: 16191da177e4SLinus Torvalds * Return value with the low bits set means error value, 16201da177e4SLinus Torvalds * ie 16211da177e4SLinus Torvalds * if (ret & ~PAGE_MASK) 16221da177e4SLinus Torvalds * error = ret; 16231da177e4SLinus Torvalds * 16241da177e4SLinus Torvalds * This function "knows" that -ENOMEM has the bits set. 16251da177e4SLinus Torvalds */ 16261da177e4SLinus Torvalds unsigned long 16274b439e25SChristophe Leroy generic_get_unmapped_area(struct file *filp, unsigned long addr, 16284b439e25SChristophe Leroy unsigned long len, unsigned long pgoff, 16294b439e25SChristophe Leroy unsigned long flags) 16301da177e4SLinus Torvalds { 16311da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 16321be7107fSHugh Dickins struct vm_area_struct *vma, *prev; 1633db4fbfb9SMichel Lespinasse struct vm_unmapped_area_info info; 16342cb4de08SChristophe Leroy const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags); 16351da177e4SLinus Torvalds 1636f6795053SSteve Capper if (len > mmap_end - mmap_min_addr) 16371da177e4SLinus Torvalds return -ENOMEM; 16381da177e4SLinus Torvalds 163906abdfb4SBenjamin Herrenschmidt if (flags & MAP_FIXED) 164006abdfb4SBenjamin Herrenschmidt return addr; 164106abdfb4SBenjamin Herrenschmidt 16421da177e4SLinus Torvalds if (addr) { 16431da177e4SLinus Torvalds addr = PAGE_ALIGN(addr); 16441be7107fSHugh Dickins vma = find_vma_prev(mm, addr, &prev); 1645f6795053SSteve Capper if (mmap_end - len >= addr && addr >= mmap_min_addr && 16461be7107fSHugh Dickins (!vma || addr + len <= vm_start_gap(vma)) && 16471be7107fSHugh Dickins (!prev || addr >= vm_end_gap(prev))) 16481da177e4SLinus Torvalds return addr; 16491da177e4SLinus Torvalds } 16501da177e4SLinus Torvalds 1651db4fbfb9SMichel Lespinasse info.flags = 0; 1652db4fbfb9SMichel Lespinasse info.length = len; 16534e99b021SHeiko Carstens info.low_limit = mm->mmap_base; 1654f6795053SSteve Capper info.high_limit = mmap_end; 1655db4fbfb9SMichel Lespinasse info.align_mask = 0; 165609ef5283SJaewon Kim info.align_offset = 0; 1657db4fbfb9SMichel Lespinasse return vm_unmapped_area(&info); 16581da177e4SLinus Torvalds } 16594b439e25SChristophe Leroy 16604b439e25SChristophe Leroy #ifndef HAVE_ARCH_UNMAPPED_AREA 16614b439e25SChristophe Leroy unsigned long 16624b439e25SChristophe Leroy arch_get_unmapped_area(struct file *filp, unsigned long addr, 16634b439e25SChristophe Leroy unsigned long len, unsigned long pgoff, 16644b439e25SChristophe Leroy unsigned long flags) 16654b439e25SChristophe Leroy { 16664b439e25SChristophe Leroy return generic_get_unmapped_area(filp, addr, len, pgoff, flags); 16674b439e25SChristophe Leroy } 16681da177e4SLinus Torvalds #endif 16691da177e4SLinus Torvalds 16701da177e4SLinus Torvalds /* 16711da177e4SLinus Torvalds * This mmap-allocator allocates new areas top-down from below the 16721da177e4SLinus Torvalds * stack's low limit (the base): 16731da177e4SLinus Torvalds */ 16741da177e4SLinus Torvalds unsigned long 16754b439e25SChristophe Leroy generic_get_unmapped_area_topdown(struct file *filp, unsigned long addr, 167643cca0b1SYang Fan unsigned long len, unsigned long pgoff, 167743cca0b1SYang Fan unsigned long flags) 16781da177e4SLinus Torvalds { 16791be7107fSHugh Dickins struct vm_area_struct *vma, *prev; 16801da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 1681db4fbfb9SMichel Lespinasse struct vm_unmapped_area_info info; 16822cb4de08SChristophe Leroy const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags); 16831da177e4SLinus Torvalds 16841da177e4SLinus Torvalds /* requested length too big for entire address space */ 1685f6795053SSteve Capper if (len > mmap_end - mmap_min_addr) 16861da177e4SLinus Torvalds return -ENOMEM; 16871da177e4SLinus Torvalds 168806abdfb4SBenjamin Herrenschmidt if (flags & MAP_FIXED) 168906abdfb4SBenjamin Herrenschmidt return addr; 169006abdfb4SBenjamin Herrenschmidt 16911da177e4SLinus Torvalds /* requesting a specific address */ 16921da177e4SLinus Torvalds if (addr) { 16931da177e4SLinus Torvalds addr = PAGE_ALIGN(addr); 16941be7107fSHugh Dickins vma = find_vma_prev(mm, addr, &prev); 1695f6795053SSteve Capper if (mmap_end - len >= addr && addr >= mmap_min_addr && 16961be7107fSHugh Dickins (!vma || addr + len <= vm_start_gap(vma)) && 16971be7107fSHugh Dickins (!prev || addr >= vm_end_gap(prev))) 16981da177e4SLinus Torvalds return addr; 16991da177e4SLinus Torvalds } 17001da177e4SLinus Torvalds 1701db4fbfb9SMichel Lespinasse info.flags = VM_UNMAPPED_AREA_TOPDOWN; 1702db4fbfb9SMichel Lespinasse info.length = len; 17032afc745fSAkira Takeuchi info.low_limit = max(PAGE_SIZE, mmap_min_addr); 1704f6795053SSteve Capper info.high_limit = arch_get_mmap_base(addr, mm->mmap_base); 1705db4fbfb9SMichel Lespinasse info.align_mask = 0; 170609ef5283SJaewon Kim info.align_offset = 0; 1707db4fbfb9SMichel Lespinasse addr = vm_unmapped_area(&info); 1708b716ad95SXiao Guangrong 17091da177e4SLinus Torvalds /* 17101da177e4SLinus Torvalds * A failed mmap() very likely causes application failure, 17111da177e4SLinus Torvalds * so fall back to the bottom-up function here. This scenario 17121da177e4SLinus Torvalds * can happen with large stack limits and large mmap() 17131da177e4SLinus Torvalds * allocations. 17141da177e4SLinus Torvalds */ 1715de1741a1SAlexander Kuleshov if (offset_in_page(addr)) { 1716db4fbfb9SMichel Lespinasse VM_BUG_ON(addr != -ENOMEM); 1717db4fbfb9SMichel Lespinasse info.flags = 0; 1718db4fbfb9SMichel Lespinasse info.low_limit = TASK_UNMAPPED_BASE; 1719f6795053SSteve Capper info.high_limit = mmap_end; 1720db4fbfb9SMichel Lespinasse addr = vm_unmapped_area(&info); 1721db4fbfb9SMichel Lespinasse } 17221da177e4SLinus Torvalds 17231da177e4SLinus Torvalds return addr; 17241da177e4SLinus Torvalds } 17254b439e25SChristophe Leroy 17264b439e25SChristophe Leroy #ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN 17274b439e25SChristophe Leroy unsigned long 17284b439e25SChristophe Leroy arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr, 17294b439e25SChristophe Leroy unsigned long len, unsigned long pgoff, 17304b439e25SChristophe Leroy unsigned long flags) 17314b439e25SChristophe Leroy { 17324b439e25SChristophe Leroy return generic_get_unmapped_area_topdown(filp, addr, len, pgoff, flags); 17334b439e25SChristophe Leroy } 17341da177e4SLinus Torvalds #endif 17351da177e4SLinus Torvalds 17361da177e4SLinus Torvalds unsigned long 17371da177e4SLinus Torvalds get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, 17381da177e4SLinus Torvalds unsigned long pgoff, unsigned long flags) 17391da177e4SLinus Torvalds { 174006abdfb4SBenjamin Herrenschmidt unsigned long (*get_area)(struct file *, unsigned long, 174106abdfb4SBenjamin Herrenschmidt unsigned long, unsigned long, unsigned long); 174207ab67c8SLinus Torvalds 17439206de95SAl Viro unsigned long error = arch_mmap_check(addr, len, flags); 17449206de95SAl Viro if (error) 17459206de95SAl Viro return error; 17469206de95SAl Viro 17479206de95SAl Viro /* Careful about overflows.. */ 17489206de95SAl Viro if (len > TASK_SIZE) 17499206de95SAl Viro return -ENOMEM; 17509206de95SAl Viro 175107ab67c8SLinus Torvalds get_area = current->mm->get_unmapped_area; 1752c01d5b30SHugh Dickins if (file) { 1753c01d5b30SHugh Dickins if (file->f_op->get_unmapped_area) 175407ab67c8SLinus Torvalds get_area = file->f_op->get_unmapped_area; 1755c01d5b30SHugh Dickins } else if (flags & MAP_SHARED) { 1756c01d5b30SHugh Dickins /* 1757c01d5b30SHugh Dickins * mmap_region() will call shmem_zero_setup() to create a file, 1758c01d5b30SHugh Dickins * so use shmem's get_unmapped_area in case it can be huge. 175945e55300SPeter Collingbourne * do_mmap() will clear pgoff, so match alignment. 1760c01d5b30SHugh Dickins */ 1761c01d5b30SHugh Dickins pgoff = 0; 1762c01d5b30SHugh Dickins get_area = shmem_get_unmapped_area; 1763c01d5b30SHugh Dickins } 1764c01d5b30SHugh Dickins 176507ab67c8SLinus Torvalds addr = get_area(file, addr, len, pgoff, flags); 176607ab67c8SLinus Torvalds if (IS_ERR_VALUE(addr)) 176707ab67c8SLinus Torvalds return addr; 176807ab67c8SLinus Torvalds 17691da177e4SLinus Torvalds if (addr > TASK_SIZE - len) 17701da177e4SLinus Torvalds return -ENOMEM; 1771de1741a1SAlexander Kuleshov if (offset_in_page(addr)) 17721da177e4SLinus Torvalds return -EINVAL; 177306abdfb4SBenjamin Herrenschmidt 17749ac4ed4bSAl Viro error = security_mmap_addr(addr); 17759ac4ed4bSAl Viro return error ? error : addr; 17761da177e4SLinus Torvalds } 17771da177e4SLinus Torvalds 17781da177e4SLinus Torvalds EXPORT_SYMBOL(get_unmapped_area); 17791da177e4SLinus Torvalds 1780be8432e7SLiam R. Howlett /** 1781abdba2ddSLiam R. Howlett * find_vma_intersection() - Look up the first VMA which intersects the interval 1782abdba2ddSLiam R. Howlett * @mm: The process address space. 1783abdba2ddSLiam R. Howlett * @start_addr: The inclusive start user address. 1784abdba2ddSLiam R. Howlett * @end_addr: The exclusive end user address. 1785abdba2ddSLiam R. Howlett * 1786abdba2ddSLiam R. Howlett * Returns: The first VMA within the provided range, %NULL otherwise. Assumes 1787abdba2ddSLiam R. Howlett * start_addr < end_addr. 1788abdba2ddSLiam R. Howlett */ 1789abdba2ddSLiam R. Howlett struct vm_area_struct *find_vma_intersection(struct mm_struct *mm, 1790abdba2ddSLiam R. Howlett unsigned long start_addr, 1791abdba2ddSLiam R. Howlett unsigned long end_addr) 1792abdba2ddSLiam R. Howlett { 1793abdba2ddSLiam R. Howlett unsigned long index = start_addr; 1794abdba2ddSLiam R. Howlett 1795abdba2ddSLiam R. Howlett mmap_assert_locked(mm); 17967964cf8cSLiam R. Howlett return mt_find(&mm->mm_mt, &index, end_addr - 1); 1797abdba2ddSLiam R. Howlett } 1798abdba2ddSLiam R. Howlett EXPORT_SYMBOL(find_vma_intersection); 1799abdba2ddSLiam R. Howlett 1800abdba2ddSLiam R. Howlett /** 1801be8432e7SLiam R. Howlett * find_vma() - Find the VMA for a given address, or the next VMA. 1802be8432e7SLiam R. Howlett * @mm: The mm_struct to check 1803be8432e7SLiam R. Howlett * @addr: The address 1804be8432e7SLiam R. Howlett * 1805be8432e7SLiam R. Howlett * Returns: The VMA associated with addr, or the next VMA. 1806be8432e7SLiam R. Howlett * May return %NULL in the case of no VMA at addr or above. 1807be8432e7SLiam R. Howlett */ 18081da177e4SLinus Torvalds struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) 18091da177e4SLinus Torvalds { 1810be8432e7SLiam R. Howlett unsigned long index = addr; 18111da177e4SLinus Torvalds 18125b78ed24SLuigi Rizzo mmap_assert_locked(mm); 18137964cf8cSLiam R. Howlett return mt_find(&mm->mm_mt, &index, ULONG_MAX); 18141da177e4SLinus Torvalds } 18151da177e4SLinus Torvalds EXPORT_SYMBOL(find_vma); 18161da177e4SLinus Torvalds 18177fdbd37dSLiam R. Howlett /** 18187fdbd37dSLiam R. Howlett * find_vma_prev() - Find the VMA for a given address, or the next vma and 18197fdbd37dSLiam R. Howlett * set %pprev to the previous VMA, if any. 18207fdbd37dSLiam R. Howlett * @mm: The mm_struct to check 18217fdbd37dSLiam R. Howlett * @addr: The address 18227fdbd37dSLiam R. Howlett * @pprev: The pointer to set to the previous VMA 18237fdbd37dSLiam R. Howlett * 18247fdbd37dSLiam R. Howlett * Note that RCU lock is missing here since the external mmap_lock() is used 18257fdbd37dSLiam R. Howlett * instead. 18267fdbd37dSLiam R. Howlett * 18277fdbd37dSLiam R. Howlett * Returns: The VMA associated with @addr, or the next vma. 18287fdbd37dSLiam R. Howlett * May return %NULL in the case of no vma at addr or above. 18296bd4837dSKOSAKI Motohiro */ 18301da177e4SLinus Torvalds struct vm_area_struct * 18311da177e4SLinus Torvalds find_vma_prev(struct mm_struct *mm, unsigned long addr, 18321da177e4SLinus Torvalds struct vm_area_struct **pprev) 18331da177e4SLinus Torvalds { 18346bd4837dSKOSAKI Motohiro struct vm_area_struct *vma; 18357fdbd37dSLiam R. Howlett MA_STATE(mas, &mm->mm_mt, addr, addr); 18361da177e4SLinus Torvalds 18377fdbd37dSLiam R. Howlett vma = mas_walk(&mas); 18387fdbd37dSLiam R. Howlett *pprev = mas_prev(&mas, 0); 18397fdbd37dSLiam R. Howlett if (!vma) 18407fdbd37dSLiam R. Howlett vma = mas_next(&mas, ULONG_MAX); 18416bd4837dSKOSAKI Motohiro return vma; 18421da177e4SLinus Torvalds } 18431da177e4SLinus Torvalds 18441da177e4SLinus Torvalds /* 18451da177e4SLinus Torvalds * Verify that the stack growth is acceptable and 18461da177e4SLinus Torvalds * update accounting. This is shared with both the 18471da177e4SLinus Torvalds * grow-up and grow-down cases. 18481da177e4SLinus Torvalds */ 18491be7107fSHugh Dickins static int acct_stack_growth(struct vm_area_struct *vma, 18501be7107fSHugh Dickins unsigned long size, unsigned long grow) 18511da177e4SLinus Torvalds { 18521da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 18531be7107fSHugh Dickins unsigned long new_start; 18541da177e4SLinus Torvalds 18551da177e4SLinus Torvalds /* address space limit tests */ 185684638335SKonstantin Khlebnikov if (!may_expand_vm(mm, vma->vm_flags, grow)) 18571da177e4SLinus Torvalds return -ENOMEM; 18581da177e4SLinus Torvalds 18591da177e4SLinus Torvalds /* Stack limit test */ 186024c79d8eSKrzysztof Opasiak if (size > rlimit(RLIMIT_STACK)) 18611da177e4SLinus Torvalds return -ENOMEM; 18621da177e4SLinus Torvalds 18631da177e4SLinus Torvalds /* mlock limit tests */ 1864c5d8a364SMiaohe Lin if (mlock_future_check(mm, vma->vm_flags, grow << PAGE_SHIFT)) 18651da177e4SLinus Torvalds return -ENOMEM; 18661da177e4SLinus Torvalds 18670d59a01bSAdam Litke /* Check to ensure the stack will not grow into a hugetlb-only region */ 18680d59a01bSAdam Litke new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start : 18690d59a01bSAdam Litke vma->vm_end - size; 18700d59a01bSAdam Litke if (is_hugepage_only_range(vma->vm_mm, new_start, size)) 18710d59a01bSAdam Litke return -EFAULT; 18720d59a01bSAdam Litke 18731da177e4SLinus Torvalds /* 18741da177e4SLinus Torvalds * Overcommit.. This must be the final test, as it will 18751da177e4SLinus Torvalds * update security statistics. 18761da177e4SLinus Torvalds */ 187705fa199dSHugh Dickins if (security_vm_enough_memory_mm(mm, grow)) 18781da177e4SLinus Torvalds return -ENOMEM; 18791da177e4SLinus Torvalds 18801da177e4SLinus Torvalds return 0; 18811da177e4SLinus Torvalds } 18821da177e4SLinus Torvalds 188346dea3d0SHugh Dickins #if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64) 18841da177e4SLinus Torvalds /* 188546dea3d0SHugh Dickins * PA-RISC uses this for its stack; IA64 for its Register Backing Store. 188646dea3d0SHugh Dickins * vma is the last one with address > vma->vm_end. Have to extend vma. 18871da177e4SLinus Torvalds */ 188846dea3d0SHugh Dickins int expand_upwards(struct vm_area_struct *vma, unsigned long address) 18891da177e4SLinus Torvalds { 189009357814SOleg Nesterov struct mm_struct *mm = vma->vm_mm; 18911be7107fSHugh Dickins struct vm_area_struct *next; 18921be7107fSHugh Dickins unsigned long gap_addr; 189312352d3cSKonstantin Khlebnikov int error = 0; 1894d4af56c5SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 18951da177e4SLinus Torvalds 18961da177e4SLinus Torvalds if (!(vma->vm_flags & VM_GROWSUP)) 18971da177e4SLinus Torvalds return -EFAULT; 18981da177e4SLinus Torvalds 1899bd726c90SHelge Deller /* Guard against exceeding limits of the address space. */ 19001be7107fSHugh Dickins address &= PAGE_MASK; 190137511fb5SHelge Deller if (address >= (TASK_SIZE & PAGE_MASK)) 190212352d3cSKonstantin Khlebnikov return -ENOMEM; 1903bd726c90SHelge Deller address += PAGE_SIZE; 190412352d3cSKonstantin Khlebnikov 19051be7107fSHugh Dickins /* Enforce stack_guard_gap */ 19061be7107fSHugh Dickins gap_addr = address + stack_guard_gap; 1907bd726c90SHelge Deller 1908bd726c90SHelge Deller /* Guard against overflow */ 1909bd726c90SHelge Deller if (gap_addr < address || gap_addr > TASK_SIZE) 1910bd726c90SHelge Deller gap_addr = TASK_SIZE; 1911bd726c90SHelge Deller 1912763ecb03SLiam R. Howlett next = find_vma_intersection(mm, vma->vm_end, gap_addr); 1913763ecb03SLiam R. Howlett if (next && vma_is_accessible(next)) { 19141be7107fSHugh Dickins if (!(next->vm_flags & VM_GROWSUP)) 19151be7107fSHugh Dickins return -ENOMEM; 19161be7107fSHugh Dickins /* Check that both stack segments have the same anon_vma? */ 19171be7107fSHugh Dickins } 19181be7107fSHugh Dickins 1919c5d5546eSVernon Yang if (mas_preallocate(&mas, GFP_KERNEL)) 19201da177e4SLinus Torvalds return -ENOMEM; 19211da177e4SLinus Torvalds 1922d4af56c5SLiam R. Howlett /* We must make sure the anon_vma is allocated. */ 1923d4af56c5SLiam R. Howlett if (unlikely(anon_vma_prepare(vma))) { 1924d4af56c5SLiam R. Howlett mas_destroy(&mas); 1925d4af56c5SLiam R. Howlett return -ENOMEM; 1926d4af56c5SLiam R. Howlett } 1927d4af56c5SLiam R. Howlett 19281da177e4SLinus Torvalds /* 19291da177e4SLinus Torvalds * vma->vm_start/vm_end cannot change under us because the caller 1930c1e8d7c6SMichel Lespinasse * is required to hold the mmap_lock in read mode. We need the 19311da177e4SLinus Torvalds * anon_vma lock to serialize against concurrent expand_stacks. 19321da177e4SLinus Torvalds */ 193312352d3cSKonstantin Khlebnikov anon_vma_lock_write(vma->anon_vma); 19341da177e4SLinus Torvalds 19351da177e4SLinus Torvalds /* Somebody else might have raced and expanded it already */ 19361da177e4SLinus Torvalds if (address > vma->vm_end) { 19371da177e4SLinus Torvalds unsigned long size, grow; 19381da177e4SLinus Torvalds 19391da177e4SLinus Torvalds size = address - vma->vm_start; 19401da177e4SLinus Torvalds grow = (address - vma->vm_end) >> PAGE_SHIFT; 19411da177e4SLinus Torvalds 194242c36f63SHugh Dickins error = -ENOMEM; 194342c36f63SHugh Dickins if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) { 19441da177e4SLinus Torvalds error = acct_stack_growth(vma, size, grow); 19453af9e859SEric B Munson if (!error) { 19464128997bSMichel Lespinasse /* 1947524e00b3SLiam R. Howlett * We only hold a shared mmap_lock lock here, so 1948524e00b3SLiam R. Howlett * we need to protect against concurrent vma 1949524e00b3SLiam R. Howlett * expansions. anon_vma_lock_write() doesn't 1950524e00b3SLiam R. Howlett * help here, as we don't guarantee that all 1951524e00b3SLiam R. Howlett * growable vmas in a mm share the same root 1952524e00b3SLiam R. Howlett * anon vma. So, we reuse mm->page_table_lock 1953524e00b3SLiam R. Howlett * to guard against concurrent vma expansions. 19544128997bSMichel Lespinasse */ 195509357814SOleg Nesterov spin_lock(&mm->page_table_lock); 195687e8827bSOleg Nesterov if (vma->vm_flags & VM_LOCKED) 195709357814SOleg Nesterov mm->locked_vm += grow; 195884638335SKonstantin Khlebnikov vm_stat_account(mm, vma->vm_flags, grow); 1959bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(vma); 19601da177e4SLinus Torvalds vma->vm_end = address; 1961d4af56c5SLiam R. Howlett /* Overwrite old entry in mtree. */ 1962fbcc3104SLiam R. Howlett mas_set_range(&mas, vma->vm_start, address - 1); 1963fbcc3104SLiam R. Howlett mas_store_prealloc(&mas, vma); 1964bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(vma); 196509357814SOleg Nesterov spin_unlock(&mm->page_table_lock); 19664128997bSMichel Lespinasse 19673af9e859SEric B Munson perf_event_mmap(vma); 19683af9e859SEric B Munson } 19691da177e4SLinus Torvalds } 197042c36f63SHugh Dickins } 197112352d3cSKonstantin Khlebnikov anon_vma_unlock_write(vma->anon_vma); 1972c791576cSYang Shi khugepaged_enter_vma(vma, vma->vm_flags); 1973d4af56c5SLiam R. Howlett mas_destroy(&mas); 19741da177e4SLinus Torvalds return error; 19751da177e4SLinus Torvalds } 197646dea3d0SHugh Dickins #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */ 197746dea3d0SHugh Dickins 19781da177e4SLinus Torvalds /* 19791da177e4SLinus Torvalds * vma is the first one with address < vma->vm_start. Have to extend vma. 19801da177e4SLinus Torvalds */ 1981524e00b3SLiam R. Howlett int expand_downwards(struct vm_area_struct *vma, unsigned long address) 19821da177e4SLinus Torvalds { 198309357814SOleg Nesterov struct mm_struct *mm = vma->vm_mm; 1984763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, vma->vm_start, vma->vm_start); 19851be7107fSHugh Dickins struct vm_area_struct *prev; 19860a1d5299SJann Horn int error = 0; 19871da177e4SLinus Torvalds 19888869477aSEric Paris address &= PAGE_MASK; 19890a1d5299SJann Horn if (address < mmap_min_addr) 19900a1d5299SJann Horn return -EPERM; 19918869477aSEric Paris 19921be7107fSHugh Dickins /* Enforce stack_guard_gap */ 1993763ecb03SLiam R. Howlett prev = mas_prev(&mas, 0); 19941be7107fSHugh Dickins /* Check that both stack segments have the same anon_vma? */ 199532e4e6d5SOleg Nesterov if (prev && !(prev->vm_flags & VM_GROWSDOWN) && 19963122e80eSAnshuman Khandual vma_is_accessible(prev)) { 199732e4e6d5SOleg Nesterov if (address - prev->vm_end < stack_guard_gap) 199832e4e6d5SOleg Nesterov return -ENOMEM; 19991be7107fSHugh Dickins } 20001be7107fSHugh Dickins 2001c5d5546eSVernon Yang if (mas_preallocate(&mas, GFP_KERNEL)) 200212352d3cSKonstantin Khlebnikov return -ENOMEM; 20031da177e4SLinus Torvalds 2004d4af56c5SLiam R. Howlett /* We must make sure the anon_vma is allocated. */ 2005d4af56c5SLiam R. Howlett if (unlikely(anon_vma_prepare(vma))) { 2006d4af56c5SLiam R. Howlett mas_destroy(&mas); 2007d4af56c5SLiam R. Howlett return -ENOMEM; 2008d4af56c5SLiam R. Howlett } 2009d4af56c5SLiam R. Howlett 20101da177e4SLinus Torvalds /* 20111da177e4SLinus Torvalds * vma->vm_start/vm_end cannot change under us because the caller 2012c1e8d7c6SMichel Lespinasse * is required to hold the mmap_lock in read mode. We need the 20131da177e4SLinus Torvalds * anon_vma lock to serialize against concurrent expand_stacks. 20141da177e4SLinus Torvalds */ 201512352d3cSKonstantin Khlebnikov anon_vma_lock_write(vma->anon_vma); 20161da177e4SLinus Torvalds 20171da177e4SLinus Torvalds /* Somebody else might have raced and expanded it already */ 20181da177e4SLinus Torvalds if (address < vma->vm_start) { 20191da177e4SLinus Torvalds unsigned long size, grow; 20201da177e4SLinus Torvalds 20211da177e4SLinus Torvalds size = vma->vm_end - address; 20221da177e4SLinus Torvalds grow = (vma->vm_start - address) >> PAGE_SHIFT; 20231da177e4SLinus Torvalds 2024a626ca6aSLinus Torvalds error = -ENOMEM; 2025a626ca6aSLinus Torvalds if (grow <= vma->vm_pgoff) { 20261da177e4SLinus Torvalds error = acct_stack_growth(vma, size, grow); 20271da177e4SLinus Torvalds if (!error) { 20284128997bSMichel Lespinasse /* 2029524e00b3SLiam R. Howlett * We only hold a shared mmap_lock lock here, so 2030524e00b3SLiam R. Howlett * we need to protect against concurrent vma 2031524e00b3SLiam R. Howlett * expansions. anon_vma_lock_write() doesn't 2032524e00b3SLiam R. Howlett * help here, as we don't guarantee that all 2033524e00b3SLiam R. Howlett * growable vmas in a mm share the same root 2034524e00b3SLiam R. Howlett * anon vma. So, we reuse mm->page_table_lock 2035524e00b3SLiam R. Howlett * to guard against concurrent vma expansions. 20364128997bSMichel Lespinasse */ 203709357814SOleg Nesterov spin_lock(&mm->page_table_lock); 203887e8827bSOleg Nesterov if (vma->vm_flags & VM_LOCKED) 203909357814SOleg Nesterov mm->locked_vm += grow; 204084638335SKonstantin Khlebnikov vm_stat_account(mm, vma->vm_flags, grow); 2041bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(vma); 20421da177e4SLinus Torvalds vma->vm_start = address; 20431da177e4SLinus Torvalds vma->vm_pgoff -= grow; 2044d4af56c5SLiam R. Howlett /* Overwrite old entry in mtree. */ 2045fbcc3104SLiam R. Howlett mas_set_range(&mas, address, vma->vm_end - 1); 2046fbcc3104SLiam R. Howlett mas_store_prealloc(&mas, vma); 2047bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(vma); 204809357814SOleg Nesterov spin_unlock(&mm->page_table_lock); 20494128997bSMichel Lespinasse 20503af9e859SEric B Munson perf_event_mmap(vma); 20511da177e4SLinus Torvalds } 20521da177e4SLinus Torvalds } 2053a626ca6aSLinus Torvalds } 205412352d3cSKonstantin Khlebnikov anon_vma_unlock_write(vma->anon_vma); 2055c791576cSYang Shi khugepaged_enter_vma(vma, vma->vm_flags); 2056d4af56c5SLiam R. Howlett mas_destroy(&mas); 20571da177e4SLinus Torvalds return error; 20581da177e4SLinus Torvalds } 20591da177e4SLinus Torvalds 20601be7107fSHugh Dickins /* enforced gap between the expanding stack and other mappings. */ 20611be7107fSHugh Dickins unsigned long stack_guard_gap = 256UL<<PAGE_SHIFT; 20621be7107fSHugh Dickins 20631be7107fSHugh Dickins static int __init cmdline_parse_stack_guard_gap(char *p) 20641be7107fSHugh Dickins { 20651be7107fSHugh Dickins unsigned long val; 20661be7107fSHugh Dickins char *endptr; 20671be7107fSHugh Dickins 20681be7107fSHugh Dickins val = simple_strtoul(p, &endptr, 10); 20691be7107fSHugh Dickins if (!*endptr) 20701be7107fSHugh Dickins stack_guard_gap = val << PAGE_SHIFT; 20711be7107fSHugh Dickins 2072e6d09493SRandy Dunlap return 1; 20731be7107fSHugh Dickins } 20741be7107fSHugh Dickins __setup("stack_guard_gap=", cmdline_parse_stack_guard_gap); 20751be7107fSHugh Dickins 2076b6a2fea3SOllie Wild #ifdef CONFIG_STACK_GROWSUP 2077b6a2fea3SOllie Wild int expand_stack(struct vm_area_struct *vma, unsigned long address) 2078b6a2fea3SOllie Wild { 2079b6a2fea3SOllie Wild return expand_upwards(vma, address); 2080b6a2fea3SOllie Wild } 2081b6a2fea3SOllie Wild 2082b6a2fea3SOllie Wild struct vm_area_struct * 2083b6a2fea3SOllie Wild find_extend_vma(struct mm_struct *mm, unsigned long addr) 2084b6a2fea3SOllie Wild { 2085b6a2fea3SOllie Wild struct vm_area_struct *vma, *prev; 2086b6a2fea3SOllie Wild 2087b6a2fea3SOllie Wild addr &= PAGE_MASK; 2088b6a2fea3SOllie Wild vma = find_vma_prev(mm, addr, &prev); 2089b6a2fea3SOllie Wild if (vma && (vma->vm_start <= addr)) 2090b6a2fea3SOllie Wild return vma; 20914d45e75aSJann Horn if (!prev || expand_stack(prev, addr)) 2092b6a2fea3SOllie Wild return NULL; 2093cea10a19SMichel Lespinasse if (prev->vm_flags & VM_LOCKED) 2094fc05f566SKirill A. Shutemov populate_vma_page_range(prev, addr, prev->vm_end, NULL); 2095b6a2fea3SOllie Wild return prev; 2096b6a2fea3SOllie Wild } 2097b6a2fea3SOllie Wild #else 2098b6a2fea3SOllie Wild int expand_stack(struct vm_area_struct *vma, unsigned long address) 2099b6a2fea3SOllie Wild { 2100b6a2fea3SOllie Wild return expand_downwards(vma, address); 2101b6a2fea3SOllie Wild } 2102b6a2fea3SOllie Wild 21031da177e4SLinus Torvalds struct vm_area_struct * 21041da177e4SLinus Torvalds find_extend_vma(struct mm_struct *mm, unsigned long addr) 21051da177e4SLinus Torvalds { 21061da177e4SLinus Torvalds struct vm_area_struct *vma; 21071da177e4SLinus Torvalds unsigned long start; 21081da177e4SLinus Torvalds 21091da177e4SLinus Torvalds addr &= PAGE_MASK; 21101da177e4SLinus Torvalds vma = find_vma(mm, addr); 21111da177e4SLinus Torvalds if (!vma) 21121da177e4SLinus Torvalds return NULL; 21131da177e4SLinus Torvalds if (vma->vm_start <= addr) 21141da177e4SLinus Torvalds return vma; 21151da177e4SLinus Torvalds if (!(vma->vm_flags & VM_GROWSDOWN)) 21161da177e4SLinus Torvalds return NULL; 21171da177e4SLinus Torvalds start = vma->vm_start; 21181da177e4SLinus Torvalds if (expand_stack(vma, addr)) 21191da177e4SLinus Torvalds return NULL; 2120cea10a19SMichel Lespinasse if (vma->vm_flags & VM_LOCKED) 2121fc05f566SKirill A. Shutemov populate_vma_page_range(vma, addr, start, NULL); 21221da177e4SLinus Torvalds return vma; 21231da177e4SLinus Torvalds } 21241da177e4SLinus Torvalds #endif 21251da177e4SLinus Torvalds 2126e1d6d01aSJesse Barnes EXPORT_SYMBOL_GPL(find_extend_vma); 2127e1d6d01aSJesse Barnes 21282c0b3814SHugh Dickins /* 2129763ecb03SLiam R. Howlett * Ok - we have the memory areas we should free on a maple tree so release them, 2130763ecb03SLiam R. Howlett * and do the vma updates. 21311da177e4SLinus Torvalds * 21322c0b3814SHugh Dickins * Called with the mm semaphore held. 21331da177e4SLinus Torvalds */ 2134763ecb03SLiam R. Howlett static inline void remove_mt(struct mm_struct *mm, struct ma_state *mas) 21351da177e4SLinus Torvalds { 21364f74d2c8SLinus Torvalds unsigned long nr_accounted = 0; 2137763ecb03SLiam R. Howlett struct vm_area_struct *vma; 21384f74d2c8SLinus Torvalds 2139365e9c87SHugh Dickins /* Update high watermark before we lower total_vm */ 2140365e9c87SHugh Dickins update_hiwater_vm(mm); 2141763ecb03SLiam R. Howlett mas_for_each(mas, vma, ULONG_MAX) { 2142ab50b8edSHugh Dickins long nrpages = vma_pages(vma); 21431da177e4SLinus Torvalds 21444f74d2c8SLinus Torvalds if (vma->vm_flags & VM_ACCOUNT) 21454f74d2c8SLinus Torvalds nr_accounted += nrpages; 214684638335SKonstantin Khlebnikov vm_stat_account(mm, vma->vm_flags, -nrpages); 2147763ecb03SLiam R. Howlett remove_vma(vma); 2148763ecb03SLiam R. Howlett } 21494f74d2c8SLinus Torvalds vm_unacct_memory(nr_accounted); 21501da177e4SLinus Torvalds validate_mm(mm); 21511da177e4SLinus Torvalds } 21521da177e4SLinus Torvalds 21531da177e4SLinus Torvalds /* 21541da177e4SLinus Torvalds * Get rid of page table information in the indicated region. 21551da177e4SLinus Torvalds * 2156f10df686SPaolo 'Blaisorblade' Giarrusso * Called with the mm semaphore held. 21571da177e4SLinus Torvalds */ 2158763ecb03SLiam R. Howlett static void unmap_region(struct mm_struct *mm, struct maple_tree *mt, 2159e0da382cSHugh Dickins struct vm_area_struct *vma, struct vm_area_struct *prev, 2160763ecb03SLiam R. Howlett struct vm_area_struct *next, 216168f48381SSuren Baghdasaryan unsigned long start, unsigned long end, bool mm_wr_locked) 21621da177e4SLinus Torvalds { 2163d16dfc55SPeter Zijlstra struct mmu_gather tlb; 21641da177e4SLinus Torvalds 21651da177e4SLinus Torvalds lru_add_drain(); 2166a72afd87SWill Deacon tlb_gather_mmu(&tlb, mm); 2167365e9c87SHugh Dickins update_hiwater_rss(mm); 216868f48381SSuren Baghdasaryan unmap_vmas(&tlb, mt, vma, start, end, mm_wr_locked); 2169763ecb03SLiam R. Howlett free_pgtables(&tlb, mt, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS, 21706ee8630eSHugh Dickins next ? next->vm_start : USER_PGTABLES_CEILING); 2171ae8eba8bSWill Deacon tlb_finish_mmu(&tlb); 21721da177e4SLinus Torvalds } 21731da177e4SLinus Torvalds 21741da177e4SLinus Torvalds /* 2175def5efe0SDavid Rientjes * __split_vma() bypasses sysctl_max_map_count checking. We use this where it 2176def5efe0SDavid Rientjes * has already been checked or doesn't make sense to fail. 21770fd5a9e2SLiam R. Howlett * VMA Iterator will point to the end VMA. 21781da177e4SLinus Torvalds */ 21799760ebffSLiam R. Howlett int __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma, 21801da177e4SLinus Torvalds unsigned long addr, int new_below) 21811da177e4SLinus Torvalds { 2182b2b3b886SLiam R. Howlett struct vma_prepare vp; 21831da177e4SLinus Torvalds struct vm_area_struct *new; 2184e3975891SChen Gang int err; 21859760ebffSLiam R. Howlett 21869760ebffSLiam R. Howlett validate_mm_mt(vma->vm_mm); 21871da177e4SLinus Torvalds 2188b2b3b886SLiam R. Howlett WARN_ON(vma->vm_start >= addr); 2189b2b3b886SLiam R. Howlett WARN_ON(vma->vm_end <= addr); 2190b2b3b886SLiam R. Howlett 2191dd3b614fSDmitry Safonov if (vma->vm_ops && vma->vm_ops->may_split) { 2192dd3b614fSDmitry Safonov err = vma->vm_ops->may_split(vma, addr); 219331383c68SDan Williams if (err) 219431383c68SDan Williams return err; 219531383c68SDan Williams } 21961da177e4SLinus Torvalds 21973928d4f5SLinus Torvalds new = vm_area_dup(vma); 21981da177e4SLinus Torvalds if (!new) 2199e3975891SChen Gang return -ENOMEM; 22001da177e4SLinus Torvalds 2201b2b3b886SLiam R. Howlett err = -ENOMEM; 2202b2b3b886SLiam R. Howlett if (vma_iter_prealloc(vmi)) 2203b2b3b886SLiam R. Howlett goto out_free_vma; 2204b2b3b886SLiam R. Howlett 2205b2b3b886SLiam R. Howlett if (new_below) { 22061da177e4SLinus Torvalds new->vm_end = addr; 2207b2b3b886SLiam R. Howlett } else { 22081da177e4SLinus Torvalds new->vm_start = addr; 22091da177e4SLinus Torvalds new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT); 22101da177e4SLinus Torvalds } 22111da177e4SLinus Torvalds 2212ef0855d3SOleg Nesterov err = vma_dup_policy(vma, new); 2213ef0855d3SOleg Nesterov if (err) 2214b2b3b886SLiam R. Howlett goto out_free_vmi; 22151da177e4SLinus Torvalds 2216c4ea95d7SDaniel Forrest err = anon_vma_clone(new, vma); 2217c4ea95d7SDaniel Forrest if (err) 22185beb4930SRik van Riel goto out_free_mpol; 22195beb4930SRik van Riel 2220e9714acfSKonstantin Khlebnikov if (new->vm_file) 22211da177e4SLinus Torvalds get_file(new->vm_file); 22221da177e4SLinus Torvalds 22231da177e4SLinus Torvalds if (new->vm_ops && new->vm_ops->open) 22241da177e4SLinus Torvalds new->vm_ops->open(new); 22251da177e4SLinus Torvalds 2226b2b3b886SLiam R. Howlett init_vma_prep(&vp, vma); 2227b2b3b886SLiam R. Howlett vp.insert = new; 2228b2b3b886SLiam R. Howlett vma_prepare(&vp); 2229ccf1d78dSSuren Baghdasaryan vma_adjust_trans_huge(vma, vma->vm_start, addr, 0); 22301da177e4SLinus Torvalds 2231b2b3b886SLiam R. Howlett if (new_below) { 2232b2b3b886SLiam R. Howlett vma->vm_start = addr; 2233b2b3b886SLiam R. Howlett vma->vm_pgoff += (addr - new->vm_start) >> PAGE_SHIFT; 2234b2b3b886SLiam R. Howlett } else { 2235b2b3b886SLiam R. Howlett vma->vm_end = addr; 22369760ebffSLiam R. Howlett } 22375beb4930SRik van Riel 2238b2b3b886SLiam R. Howlett /* vma_complete stores the new vma */ 2239b2b3b886SLiam R. Howlett vma_complete(&vp, vmi, vma->vm_mm); 2240b2b3b886SLiam R. Howlett 2241b2b3b886SLiam R. Howlett /* Success. */ 2242b2b3b886SLiam R. Howlett if (new_below) 2243b2b3b886SLiam R. Howlett vma_next(vmi); 2244b2b3b886SLiam R. Howlett validate_mm_mt(vma->vm_mm); 2245b2b3b886SLiam R. Howlett return 0; 2246b2b3b886SLiam R. Howlett 22475beb4930SRik van Riel out_free_mpol: 2248ef0855d3SOleg Nesterov mpol_put(vma_policy(new)); 2249b2b3b886SLiam R. Howlett out_free_vmi: 2250b2b3b886SLiam R. Howlett vma_iter_free(vmi); 22515beb4930SRik van Riel out_free_vma: 22523928d4f5SLinus Torvalds vm_area_free(new); 22539760ebffSLiam R. Howlett validate_mm_mt(vma->vm_mm); 22545beb4930SRik van Riel return err; 22551da177e4SLinus Torvalds } 22561da177e4SLinus Torvalds 2257659ace58SKOSAKI Motohiro /* 2258659ace58SKOSAKI Motohiro * Split a vma into two pieces at address 'addr', a new vma is allocated 2259659ace58SKOSAKI Motohiro * either for the first part or the tail. 2260659ace58SKOSAKI Motohiro */ 22619760ebffSLiam R. Howlett int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma, 2262659ace58SKOSAKI Motohiro unsigned long addr, int new_below) 2263659ace58SKOSAKI Motohiro { 22649760ebffSLiam R. Howlett if (vma->vm_mm->map_count >= sysctl_max_map_count) 2265659ace58SKOSAKI Motohiro return -ENOMEM; 2266659ace58SKOSAKI Motohiro 22679760ebffSLiam R. Howlett return __split_vma(vmi, vma, addr, new_below); 2268f2ebfe43SLiam R. Howlett } 2269f2ebfe43SLiam R. Howlett 2270763ecb03SLiam R. Howlett static inline int munmap_sidetree(struct vm_area_struct *vma, 2271763ecb03SLiam R. Howlett struct ma_state *mas_detach) 22721da177e4SLinus Torvalds { 2273*73046fd0SSuren Baghdasaryan vma_start_write(vma); 2274763ecb03SLiam R. Howlett mas_set_range(mas_detach, vma->vm_start, vma->vm_end - 1); 2275763ecb03SLiam R. Howlett if (mas_store_gfp(mas_detach, vma, GFP_KERNEL)) 2276763ecb03SLiam R. Howlett return -ENOMEM; 227711f9a21aSLiam R. Howlett 2278763ecb03SLiam R. Howlett if (vma->vm_flags & VM_LOCKED) 2279763ecb03SLiam R. Howlett vma->vm_mm->locked_vm -= vma_pages(vma); 228011f9a21aSLiam R. Howlett 2281763ecb03SLiam R. Howlett return 0; 228211f9a21aSLiam R. Howlett } 228311f9a21aSLiam R. Howlett 228411f9a21aSLiam R. Howlett /* 2285183654ceSLiam R. Howlett * do_vmi_align_munmap() - munmap the aligned region from @start to @end. 2286183654ceSLiam R. Howlett * @vmi: The vma iterator 228711f9a21aSLiam R. Howlett * @vma: The starting vm_area_struct 228811f9a21aSLiam R. Howlett * @mm: The mm_struct 228911f9a21aSLiam R. Howlett * @start: The aligned start address to munmap. 229011f9a21aSLiam R. Howlett * @end: The aligned end address to munmap. 229111f9a21aSLiam R. Howlett * @uf: The userfaultfd list_head 22928651a137SLorenzo Stoakes * @downgrade: Set to true to attempt a write downgrade of the mmap_lock 229311f9a21aSLiam R. Howlett * 229411f9a21aSLiam R. Howlett * If @downgrade is true, check return code for potential release of the lock. 229511f9a21aSLiam R. Howlett */ 229611f9a21aSLiam R. Howlett static int 2297183654ceSLiam R. Howlett do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma, 229811f9a21aSLiam R. Howlett struct mm_struct *mm, unsigned long start, 229911f9a21aSLiam R. Howlett unsigned long end, struct list_head *uf, bool downgrade) 230011f9a21aSLiam R. Howlett { 2301763ecb03SLiam R. Howlett struct vm_area_struct *prev, *next = NULL; 2302763ecb03SLiam R. Howlett struct maple_tree mt_detach; 2303763ecb03SLiam R. Howlett int count = 0; 2304d4af56c5SLiam R. Howlett int error = -ENOMEM; 2305763ecb03SLiam R. Howlett MA_STATE(mas_detach, &mt_detach, 0, 0); 2306763ecb03SLiam R. Howlett mt_init_flags(&mt_detach, MT_FLAGS_LOCK_EXTERN); 2307763ecb03SLiam R. Howlett mt_set_external_lock(&mt_detach, &mm->mmap_lock); 2308524e00b3SLiam R. Howlett 23091da177e4SLinus Torvalds /* 23101da177e4SLinus Torvalds * If we need to split any vma, do it now to save pain later. 23111da177e4SLinus Torvalds * 23121da177e4SLinus Torvalds * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially 23131da177e4SLinus Torvalds * unmapped vm_area_struct will remain in use: so lower split_vma 23141da177e4SLinus Torvalds * places tmp vma above, and higher split_vma places tmp vma below. 23151da177e4SLinus Torvalds */ 2316763ecb03SLiam R. Howlett 2317763ecb03SLiam R. Howlett /* Does it split the first one? */ 2318146425a3SHugh Dickins if (start > vma->vm_start) { 2319659ace58SKOSAKI Motohiro 2320659ace58SKOSAKI Motohiro /* 2321659ace58SKOSAKI Motohiro * Make sure that map_count on return from munmap() will 2322659ace58SKOSAKI Motohiro * not exceed its limit; but let map_count go just above 2323659ace58SKOSAKI Motohiro * its limit temporarily, to help free resources as expected. 2324659ace58SKOSAKI Motohiro */ 2325659ace58SKOSAKI Motohiro if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count) 2326d4af56c5SLiam R. Howlett goto map_count_exceeded; 2327659ace58SKOSAKI Motohiro 23289760ebffSLiam R. Howlett error = __split_vma(vmi, vma, start, 0); 23291da177e4SLinus Torvalds if (error) 2330763ecb03SLiam R. Howlett goto start_split_failed; 233111f9a21aSLiam R. Howlett 23320fd5a9e2SLiam R. Howlett vma = vma_iter_load(vmi); 23331da177e4SLinus Torvalds } 23341da177e4SLinus Torvalds 2335183654ceSLiam R. Howlett prev = vma_prev(vmi); 2336763ecb03SLiam R. Howlett if (unlikely((!prev))) 2337183654ceSLiam R. Howlett vma_iter_set(vmi, start); 233811f9a21aSLiam R. Howlett 2339763ecb03SLiam R. Howlett /* 2340763ecb03SLiam R. Howlett * Detach a range of VMAs from the mm. Using next as a temp variable as 2341763ecb03SLiam R. Howlett * it is always overwritten. 2342763ecb03SLiam R. Howlett */ 2343183654ceSLiam R. Howlett for_each_vma_range(*vmi, next, end) { 2344763ecb03SLiam R. Howlett /* Does it split the end? */ 2345763ecb03SLiam R. Howlett if (next->vm_end > end) { 23466b73cff2SLiam R. Howlett error = __split_vma(vmi, next, end, 0); 23471da177e4SLinus Torvalds if (error) 2348763ecb03SLiam R. Howlett goto end_split_failed; 234911f9a21aSLiam R. Howlett } 2350763ecb03SLiam R. Howlett error = munmap_sidetree(next, &mas_detach); 2351763ecb03SLiam R. Howlett if (error) 2352763ecb03SLiam R. Howlett goto munmap_sidetree_failed; 2353763ecb03SLiam R. Howlett 2354763ecb03SLiam R. Howlett count++; 2355763ecb03SLiam R. Howlett #ifdef CONFIG_DEBUG_VM_MAPLE_TREE 2356763ecb03SLiam R. Howlett BUG_ON(next->vm_start < start); 2357763ecb03SLiam R. Howlett BUG_ON(next->vm_start > end); 2358763ecb03SLiam R. Howlett #endif 2359763ecb03SLiam R. Howlett } 2360763ecb03SLiam R. Howlett 2361183654ceSLiam R. Howlett next = vma_next(vmi); 23622376dd7cSAndrea Arcangeli if (unlikely(uf)) { 23632376dd7cSAndrea Arcangeli /* 23642376dd7cSAndrea Arcangeli * If userfaultfd_unmap_prep returns an error the vmas 2365f0953a1bSIngo Molnar * will remain split, but userland will get a 23662376dd7cSAndrea Arcangeli * highly unexpected error anyway. This is no 23672376dd7cSAndrea Arcangeli * different than the case where the first of the two 23682376dd7cSAndrea Arcangeli * __split_vma fails, but we don't undo the first 23692376dd7cSAndrea Arcangeli * split, despite we could. This is unlikely enough 23702376dd7cSAndrea Arcangeli * failure that it's not worth optimizing it for. 23712376dd7cSAndrea Arcangeli */ 237269dbe6daSLiam R. Howlett error = userfaultfd_unmap_prep(mm, start, end, uf); 237311f9a21aSLiam R. Howlett 23742376dd7cSAndrea Arcangeli if (error) 2375d4af56c5SLiam R. Howlett goto userfaultfd_error; 23762376dd7cSAndrea Arcangeli } 23772376dd7cSAndrea Arcangeli 2378763ecb03SLiam R. Howlett #if defined(CONFIG_DEBUG_VM_MAPLE_TREE) 2379763ecb03SLiam R. Howlett /* Make sure no VMAs are about to be lost. */ 2380763ecb03SLiam R. Howlett { 2381763ecb03SLiam R. Howlett MA_STATE(test, &mt_detach, start, end - 1); 2382763ecb03SLiam R. Howlett struct vm_area_struct *vma_mas, *vma_test; 2383763ecb03SLiam R. Howlett int test_count = 0; 2384763ecb03SLiam R. Howlett 2385183654ceSLiam R. Howlett vma_iter_set(vmi, start); 2386763ecb03SLiam R. Howlett rcu_read_lock(); 2387763ecb03SLiam R. Howlett vma_test = mas_find(&test, end - 1); 2388183654ceSLiam R. Howlett for_each_vma_range(*vmi, vma_mas, end) { 2389763ecb03SLiam R. Howlett BUG_ON(vma_mas != vma_test); 2390763ecb03SLiam R. Howlett test_count++; 2391763ecb03SLiam R. Howlett vma_test = mas_next(&test, end - 1); 2392763ecb03SLiam R. Howlett } 2393763ecb03SLiam R. Howlett rcu_read_unlock(); 2394763ecb03SLiam R. Howlett BUG_ON(count != test_count); 2395763ecb03SLiam R. Howlett } 2396763ecb03SLiam R. Howlett #endif 23970378c0a0SLiam R. Howlett /* Point of no return */ 2398183654ceSLiam R. Howlett vma_iter_set(vmi, start); 2399183654ceSLiam R. Howlett if (vma_iter_clear_gfp(vmi, start, end, GFP_KERNEL)) 24000378c0a0SLiam R. Howlett return -ENOMEM; 24010378c0a0SLiam R. Howlett 2402763ecb03SLiam R. Howlett mm->map_count -= count; 240311f9a21aSLiam R. Howlett /* 240411f9a21aSLiam R. Howlett * Do not downgrade mmap_lock if we are next to VM_GROWSDOWN or 240511f9a21aSLiam R. Howlett * VM_GROWSUP VMA. Such VMAs can change their size under 240611f9a21aSLiam R. Howlett * down_read(mmap_lock) and collide with the VMA we are about to unmap. 240711f9a21aSLiam R. Howlett */ 240811f9a21aSLiam R. Howlett if (downgrade) { 2409763ecb03SLiam R. Howlett if (next && (next->vm_flags & VM_GROWSDOWN)) 241011f9a21aSLiam R. Howlett downgrade = false; 241111f9a21aSLiam R. Howlett else if (prev && (prev->vm_flags & VM_GROWSUP)) 241211f9a21aSLiam R. Howlett downgrade = false; 241311f9a21aSLiam R. Howlett else 2414d8ed45c5SMichel Lespinasse mmap_write_downgrade(mm); 241511f9a21aSLiam R. Howlett } 2416dd2283f2SYang Shi 241768f48381SSuren Baghdasaryan /* 241868f48381SSuren Baghdasaryan * We can free page tables without write-locking mmap_lock because VMAs 241968f48381SSuren Baghdasaryan * were isolated before we downgraded mmap_lock. 242068f48381SSuren Baghdasaryan */ 242168f48381SSuren Baghdasaryan unmap_region(mm, &mt_detach, vma, prev, next, start, end, !downgrade); 2422763ecb03SLiam R. Howlett /* Statistics and freeing VMAs */ 2423763ecb03SLiam R. Howlett mas_set(&mas_detach, start); 2424763ecb03SLiam R. Howlett remove_mt(mm, &mas_detach); 2425763ecb03SLiam R. Howlett __mt_destroy(&mt_detach); 24261da177e4SLinus Torvalds 2427524e00b3SLiam R. Howlett 2428524e00b3SLiam R. Howlett validate_mm(mm); 2429dd2283f2SYang Shi return downgrade ? 1 : 0; 2430d4af56c5SLiam R. Howlett 2431d4af56c5SLiam R. Howlett userfaultfd_error: 2432763ecb03SLiam R. Howlett munmap_sidetree_failed: 2433763ecb03SLiam R. Howlett end_split_failed: 2434763ecb03SLiam R. Howlett __mt_destroy(&mt_detach); 2435763ecb03SLiam R. Howlett start_split_failed: 2436763ecb03SLiam R. Howlett map_count_exceeded: 2437d4af56c5SLiam R. Howlett return error; 24381da177e4SLinus Torvalds } 24391da177e4SLinus Torvalds 244011f9a21aSLiam R. Howlett /* 2441183654ceSLiam R. Howlett * do_vmi_munmap() - munmap a given range. 2442183654ceSLiam R. Howlett * @vmi: The vma iterator 244311f9a21aSLiam R. Howlett * @mm: The mm_struct 244411f9a21aSLiam R. Howlett * @start: The start address to munmap 244511f9a21aSLiam R. Howlett * @len: The length of the range to munmap 244611f9a21aSLiam R. Howlett * @uf: The userfaultfd list_head 244711f9a21aSLiam R. Howlett * @downgrade: set to true if the user wants to attempt to write_downgrade the 24488651a137SLorenzo Stoakes * mmap_lock 244911f9a21aSLiam R. Howlett * 245011f9a21aSLiam R. Howlett * This function takes a @mas that is either pointing to the previous VMA or set 245111f9a21aSLiam R. Howlett * to MA_START and sets it up to remove the mapping(s). The @len will be 245211f9a21aSLiam R. Howlett * aligned and any arch_unmap work will be preformed. 245311f9a21aSLiam R. Howlett * 245411f9a21aSLiam R. Howlett * Returns: -EINVAL on failure, 1 on success and unlock, 0 otherwise. 245511f9a21aSLiam R. Howlett */ 2456183654ceSLiam R. Howlett int do_vmi_munmap(struct vma_iterator *vmi, struct mm_struct *mm, 245711f9a21aSLiam R. Howlett unsigned long start, size_t len, struct list_head *uf, 245811f9a21aSLiam R. Howlett bool downgrade) 245911f9a21aSLiam R. Howlett { 246011f9a21aSLiam R. Howlett unsigned long end; 246111f9a21aSLiam R. Howlett struct vm_area_struct *vma; 246211f9a21aSLiam R. Howlett 246311f9a21aSLiam R. Howlett if ((offset_in_page(start)) || start > TASK_SIZE || len > TASK_SIZE-start) 246411f9a21aSLiam R. Howlett return -EINVAL; 246511f9a21aSLiam R. Howlett 246611f9a21aSLiam R. Howlett end = start + PAGE_ALIGN(len); 246711f9a21aSLiam R. Howlett if (end == start) 246811f9a21aSLiam R. Howlett return -EINVAL; 246911f9a21aSLiam R. Howlett 247011f9a21aSLiam R. Howlett /* arch_unmap() might do unmaps itself. */ 247111f9a21aSLiam R. Howlett arch_unmap(mm, start, end); 247211f9a21aSLiam R. Howlett 247311f9a21aSLiam R. Howlett /* Find the first overlapping VMA */ 2474183654ceSLiam R. Howlett vma = vma_find(vmi, end); 247511f9a21aSLiam R. Howlett if (!vma) 247611f9a21aSLiam R. Howlett return 0; 247711f9a21aSLiam R. Howlett 2478183654ceSLiam R. Howlett return do_vmi_align_munmap(vmi, vma, mm, start, end, uf, downgrade); 247911f9a21aSLiam R. Howlett } 248011f9a21aSLiam R. Howlett 248111f9a21aSLiam R. Howlett /* do_munmap() - Wrapper function for non-maple tree aware do_munmap() calls. 248211f9a21aSLiam R. Howlett * @mm: The mm_struct 248311f9a21aSLiam R. Howlett * @start: The start address to munmap 248411f9a21aSLiam R. Howlett * @len: The length to be munmapped. 248511f9a21aSLiam R. Howlett * @uf: The userfaultfd list_head 248611f9a21aSLiam R. Howlett */ 2487dd2283f2SYang Shi int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, 2488dd2283f2SYang Shi struct list_head *uf) 2489dd2283f2SYang Shi { 2490183654ceSLiam R. Howlett VMA_ITERATOR(vmi, mm, start); 249111f9a21aSLiam R. Howlett 2492183654ceSLiam R. Howlett return do_vmi_munmap(&vmi, mm, start, len, uf, false); 2493dd2283f2SYang Shi } 2494dd2283f2SYang Shi 2495e99668a5SLiam R. Howlett unsigned long mmap_region(struct file *file, unsigned long addr, 2496e99668a5SLiam R. Howlett unsigned long len, vm_flags_t vm_flags, unsigned long pgoff, 2497e99668a5SLiam R. Howlett struct list_head *uf) 2498e99668a5SLiam R. Howlett { 2499e99668a5SLiam R. Howlett struct mm_struct *mm = current->mm; 2500e99668a5SLiam R. Howlett struct vm_area_struct *vma = NULL; 2501e99668a5SLiam R. Howlett struct vm_area_struct *next, *prev, *merge; 2502e99668a5SLiam R. Howlett pgoff_t pglen = len >> PAGE_SHIFT; 2503e99668a5SLiam R. Howlett unsigned long charged = 0; 2504e99668a5SLiam R. Howlett unsigned long end = addr + len; 2505e99668a5SLiam R. Howlett unsigned long merge_start = addr, merge_end = end; 2506e99668a5SLiam R. Howlett pgoff_t vm_pgoff; 2507e99668a5SLiam R. Howlett int error; 2508183654ceSLiam R. Howlett VMA_ITERATOR(vmi, mm, addr); 2509e99668a5SLiam R. Howlett 2510e99668a5SLiam R. Howlett /* Check against address space limit. */ 2511e99668a5SLiam R. Howlett if (!may_expand_vm(mm, vm_flags, len >> PAGE_SHIFT)) { 2512e99668a5SLiam R. Howlett unsigned long nr_pages; 2513e99668a5SLiam R. Howlett 2514e99668a5SLiam R. Howlett /* 2515e99668a5SLiam R. Howlett * MAP_FIXED may remove pages of mappings that intersects with 2516e99668a5SLiam R. Howlett * requested mapping. Account for the pages it would unmap. 2517e99668a5SLiam R. Howlett */ 2518e99668a5SLiam R. Howlett nr_pages = count_vma_pages_range(mm, addr, end); 2519e99668a5SLiam R. Howlett 2520e99668a5SLiam R. Howlett if (!may_expand_vm(mm, vm_flags, 2521e99668a5SLiam R. Howlett (len >> PAGE_SHIFT) - nr_pages)) 2522e99668a5SLiam R. Howlett return -ENOMEM; 2523e99668a5SLiam R. Howlett } 2524e99668a5SLiam R. Howlett 2525e99668a5SLiam R. Howlett /* Unmap any existing mapping in the area */ 2526183654ceSLiam R. Howlett if (do_vmi_munmap(&vmi, mm, addr, len, uf, false)) 2527e99668a5SLiam R. Howlett return -ENOMEM; 2528e99668a5SLiam R. Howlett 2529e99668a5SLiam R. Howlett /* 2530e99668a5SLiam R. Howlett * Private writable mapping: check memory availability 2531e99668a5SLiam R. Howlett */ 2532e99668a5SLiam R. Howlett if (accountable_mapping(file, vm_flags)) { 2533e99668a5SLiam R. Howlett charged = len >> PAGE_SHIFT; 2534e99668a5SLiam R. Howlett if (security_vm_enough_memory_mm(mm, charged)) 2535e99668a5SLiam R. Howlett return -ENOMEM; 2536e99668a5SLiam R. Howlett vm_flags |= VM_ACCOUNT; 2537e99668a5SLiam R. Howlett } 2538e99668a5SLiam R. Howlett 2539183654ceSLiam R. Howlett next = vma_next(&vmi); 2540183654ceSLiam R. Howlett prev = vma_prev(&vmi); 2541e99668a5SLiam R. Howlett if (vm_flags & VM_SPECIAL) 2542e99668a5SLiam R. Howlett goto cannot_expand; 2543e99668a5SLiam R. Howlett 2544e99668a5SLiam R. Howlett /* Attempt to expand an old mapping */ 2545e99668a5SLiam R. Howlett /* Check next */ 2546e99668a5SLiam R. Howlett if (next && next->vm_start == end && !vma_policy(next) && 2547e99668a5SLiam R. Howlett can_vma_merge_before(next, vm_flags, NULL, file, pgoff+pglen, 2548e99668a5SLiam R. Howlett NULL_VM_UFFD_CTX, NULL)) { 2549e99668a5SLiam R. Howlett merge_end = next->vm_end; 2550e99668a5SLiam R. Howlett vma = next; 2551e99668a5SLiam R. Howlett vm_pgoff = next->vm_pgoff - pglen; 2552e99668a5SLiam R. Howlett } 2553e99668a5SLiam R. Howlett 2554e99668a5SLiam R. Howlett /* Check prev */ 2555e99668a5SLiam R. Howlett if (prev && prev->vm_end == addr && !vma_policy(prev) && 2556e99668a5SLiam R. Howlett (vma ? can_vma_merge_after(prev, vm_flags, vma->anon_vma, file, 2557e99668a5SLiam R. Howlett pgoff, vma->vm_userfaultfd_ctx, NULL) : 2558e99668a5SLiam R. Howlett can_vma_merge_after(prev, vm_flags, NULL, file, pgoff, 2559e99668a5SLiam R. Howlett NULL_VM_UFFD_CTX, NULL))) { 2560e99668a5SLiam R. Howlett merge_start = prev->vm_start; 2561e99668a5SLiam R. Howlett vma = prev; 2562e99668a5SLiam R. Howlett vm_pgoff = prev->vm_pgoff; 2563e99668a5SLiam R. Howlett } 2564e99668a5SLiam R. Howlett 2565e99668a5SLiam R. Howlett 2566e99668a5SLiam R. Howlett /* Actually expand, if possible */ 2567e99668a5SLiam R. Howlett if (vma && 25683c441ab7SLiam R. Howlett !vma_expand(&vmi, vma, merge_start, merge_end, vm_pgoff, next)) { 2569e99668a5SLiam R. Howlett khugepaged_enter_vma(vma, vm_flags); 2570e99668a5SLiam R. Howlett goto expanded; 2571e99668a5SLiam R. Howlett } 2572e99668a5SLiam R. Howlett 2573e99668a5SLiam R. Howlett cannot_expand: 2574e99668a5SLiam R. Howlett /* 2575e99668a5SLiam R. Howlett * Determine the object being mapped and call the appropriate 2576e99668a5SLiam R. Howlett * specific mapper. the address has already been validated, but 2577e99668a5SLiam R. Howlett * not unmapped, but the maps are removed from the list. 2578e99668a5SLiam R. Howlett */ 2579e99668a5SLiam R. Howlett vma = vm_area_alloc(mm); 2580e99668a5SLiam R. Howlett if (!vma) { 2581e99668a5SLiam R. Howlett error = -ENOMEM; 2582e99668a5SLiam R. Howlett goto unacct_error; 2583e99668a5SLiam R. Howlett } 2584e99668a5SLiam R. Howlett 25850fd5a9e2SLiam R. Howlett vma_iter_set(&vmi, addr); 2586e99668a5SLiam R. Howlett vma->vm_start = addr; 2587e99668a5SLiam R. Howlett vma->vm_end = end; 25881c71222eSSuren Baghdasaryan vm_flags_init(vma, vm_flags); 2589e99668a5SLiam R. Howlett vma->vm_page_prot = vm_get_page_prot(vm_flags); 2590e99668a5SLiam R. Howlett vma->vm_pgoff = pgoff; 2591e99668a5SLiam R. Howlett 2592e99668a5SLiam R. Howlett if (file) { 2593e99668a5SLiam R. Howlett if (vm_flags & VM_SHARED) { 2594e99668a5SLiam R. Howlett error = mapping_map_writable(file->f_mapping); 2595e99668a5SLiam R. Howlett if (error) 2596e99668a5SLiam R. Howlett goto free_vma; 2597e99668a5SLiam R. Howlett } 2598e99668a5SLiam R. Howlett 2599e99668a5SLiam R. Howlett vma->vm_file = get_file(file); 2600e99668a5SLiam R. Howlett error = call_mmap(file, vma); 2601e99668a5SLiam R. Howlett if (error) 2602e99668a5SLiam R. Howlett goto unmap_and_free_vma; 2603e99668a5SLiam R. Howlett 2604a57b7051SLiam Howlett /* 2605a57b7051SLiam Howlett * Expansion is handled above, merging is handled below. 2606a57b7051SLiam Howlett * Drivers should not alter the address of the VMA. 2607e99668a5SLiam R. Howlett */ 2608a57b7051SLiam Howlett error = -EINVAL; 2609cc8d1b09SLiam R. Howlett if (WARN_ON((addr != vma->vm_start))) 2610a57b7051SLiam Howlett goto close_and_free_vma; 2611e99668a5SLiam R. Howlett 2612cc8d1b09SLiam R. Howlett vma_iter_set(&vmi, addr); 2613e99668a5SLiam R. Howlett /* 2614e99668a5SLiam R. Howlett * If vm_flags changed after call_mmap(), we should try merge 2615e99668a5SLiam R. Howlett * vma again as we may succeed this time. 2616e99668a5SLiam R. Howlett */ 2617e99668a5SLiam R. Howlett if (unlikely(vm_flags != vma->vm_flags && prev)) { 26189760ebffSLiam R. Howlett merge = vma_merge(&vmi, mm, prev, vma->vm_start, 26199760ebffSLiam R. Howlett vma->vm_end, vma->vm_flags, NULL, 26209760ebffSLiam R. Howlett vma->vm_file, vma->vm_pgoff, NULL, 26219760ebffSLiam R. Howlett NULL_VM_UFFD_CTX, NULL); 2622e99668a5SLiam R. Howlett if (merge) { 2623e99668a5SLiam R. Howlett /* 2624e99668a5SLiam R. Howlett * ->mmap() can change vma->vm_file and fput 2625e99668a5SLiam R. Howlett * the original file. So fput the vma->vm_file 2626e99668a5SLiam R. Howlett * here or we would add an extra fput for file 2627e99668a5SLiam R. Howlett * and cause general protection fault 2628e99668a5SLiam R. Howlett * ultimately. 2629e99668a5SLiam R. Howlett */ 2630e99668a5SLiam R. Howlett fput(vma->vm_file); 2631e99668a5SLiam R. Howlett vm_area_free(vma); 2632e99668a5SLiam R. Howlett vma = merge; 2633e99668a5SLiam R. Howlett /* Update vm_flags to pick up the change. */ 2634e99668a5SLiam R. Howlett vm_flags = vma->vm_flags; 2635e99668a5SLiam R. Howlett goto unmap_writable; 2636e99668a5SLiam R. Howlett } 2637e99668a5SLiam R. Howlett } 2638e99668a5SLiam R. Howlett 2639e99668a5SLiam R. Howlett vm_flags = vma->vm_flags; 2640e99668a5SLiam R. Howlett } else if (vm_flags & VM_SHARED) { 2641e99668a5SLiam R. Howlett error = shmem_zero_setup(vma); 2642e99668a5SLiam R. Howlett if (error) 2643e99668a5SLiam R. Howlett goto free_vma; 2644e99668a5SLiam R. Howlett } else { 2645e99668a5SLiam R. Howlett vma_set_anonymous(vma); 2646e99668a5SLiam R. Howlett } 2647e99668a5SLiam R. Howlett 2648b507808eSJoey Gouly if (map_deny_write_exec(vma, vma->vm_flags)) { 2649b507808eSJoey Gouly error = -EACCES; 2650b507808eSJoey Gouly goto close_and_free_vma; 2651b507808eSJoey Gouly } 2652b507808eSJoey Gouly 2653e99668a5SLiam R. Howlett /* Allow architectures to sanity-check the vm_flags */ 2654e99668a5SLiam R. Howlett error = -EINVAL; 2655cc8d1b09SLiam R. Howlett if (!arch_validate_flags(vma->vm_flags)) 2656deb0f656SCarlos Llamas goto close_and_free_vma; 2657e99668a5SLiam R. Howlett 2658e99668a5SLiam R. Howlett error = -ENOMEM; 2659cc8d1b09SLiam R. Howlett if (vma_iter_prealloc(&vmi)) 26605789151eSMike Kravetz goto close_and_free_vma; 2661e99668a5SLiam R. Howlett 2662e99668a5SLiam R. Howlett if (vma->vm_file) 2663e99668a5SLiam R. Howlett i_mmap_lock_write(vma->vm_file->f_mapping); 2664e99668a5SLiam R. Howlett 2665183654ceSLiam R. Howlett vma_iter_store(&vmi, vma); 2666e99668a5SLiam R. Howlett mm->map_count++; 2667e99668a5SLiam R. Howlett if (vma->vm_file) { 2668e99668a5SLiam R. Howlett if (vma->vm_flags & VM_SHARED) 2669e99668a5SLiam R. Howlett mapping_allow_writable(vma->vm_file->f_mapping); 2670e99668a5SLiam R. Howlett 2671e99668a5SLiam R. Howlett flush_dcache_mmap_lock(vma->vm_file->f_mapping); 2672e99668a5SLiam R. Howlett vma_interval_tree_insert(vma, &vma->vm_file->f_mapping->i_mmap); 2673e99668a5SLiam R. Howlett flush_dcache_mmap_unlock(vma->vm_file->f_mapping); 2674e99668a5SLiam R. Howlett i_mmap_unlock_write(vma->vm_file->f_mapping); 2675e99668a5SLiam R. Howlett } 2676e99668a5SLiam R. Howlett 2677e99668a5SLiam R. Howlett /* 2678e99668a5SLiam R. Howlett * vma_merge() calls khugepaged_enter_vma() either, the below 2679e99668a5SLiam R. Howlett * call covers the non-merge case. 2680e99668a5SLiam R. Howlett */ 2681e99668a5SLiam R. Howlett khugepaged_enter_vma(vma, vma->vm_flags); 2682e99668a5SLiam R. Howlett 2683e99668a5SLiam R. Howlett /* Once vma denies write, undo our temporary denial count */ 2684e99668a5SLiam R. Howlett unmap_writable: 2685e99668a5SLiam R. Howlett if (file && vm_flags & VM_SHARED) 2686e99668a5SLiam R. Howlett mapping_unmap_writable(file->f_mapping); 2687e99668a5SLiam R. Howlett file = vma->vm_file; 2688e99668a5SLiam R. Howlett expanded: 2689e99668a5SLiam R. Howlett perf_event_mmap(vma); 2690e99668a5SLiam R. Howlett 2691e99668a5SLiam R. Howlett vm_stat_account(mm, vm_flags, len >> PAGE_SHIFT); 2692e99668a5SLiam R. Howlett if (vm_flags & VM_LOCKED) { 2693e99668a5SLiam R. Howlett if ((vm_flags & VM_SPECIAL) || vma_is_dax(vma) || 2694e99668a5SLiam R. Howlett is_vm_hugetlb_page(vma) || 2695e99668a5SLiam R. Howlett vma == get_gate_vma(current->mm)) 2696e430a95aSSuren Baghdasaryan vm_flags_clear(vma, VM_LOCKED_MASK); 2697e99668a5SLiam R. Howlett else 2698e99668a5SLiam R. Howlett mm->locked_vm += (len >> PAGE_SHIFT); 2699e99668a5SLiam R. Howlett } 2700e99668a5SLiam R. Howlett 2701e99668a5SLiam R. Howlett if (file) 2702e99668a5SLiam R. Howlett uprobe_mmap(vma); 2703e99668a5SLiam R. Howlett 2704e99668a5SLiam R. Howlett /* 2705e99668a5SLiam R. Howlett * New (or expanded) vma always get soft dirty status. 2706e99668a5SLiam R. Howlett * Otherwise user-space soft-dirty page tracker won't 2707e99668a5SLiam R. Howlett * be able to distinguish situation when vma area unmapped, 2708e99668a5SLiam R. Howlett * then new mapped in-place (which must be aimed as 2709e99668a5SLiam R. Howlett * a completely new data area). 2710e99668a5SLiam R. Howlett */ 27111c71222eSSuren Baghdasaryan vm_flags_set(vma, VM_SOFTDIRTY); 2712e99668a5SLiam R. Howlett 2713e99668a5SLiam R. Howlett vma_set_page_prot(vma); 2714e99668a5SLiam R. Howlett 2715e99668a5SLiam R. Howlett validate_mm(mm); 2716e99668a5SLiam R. Howlett return addr; 2717e99668a5SLiam R. Howlett 2718deb0f656SCarlos Llamas close_and_free_vma: 2719cc8d1b09SLiam R. Howlett if (file && vma->vm_ops && vma->vm_ops->close) 2720deb0f656SCarlos Llamas vma->vm_ops->close(vma); 2721cc8d1b09SLiam R. Howlett 2722cc8d1b09SLiam R. Howlett if (file || vma->vm_file) { 2723e99668a5SLiam R. Howlett unmap_and_free_vma: 2724e99668a5SLiam R. Howlett fput(vma->vm_file); 2725e99668a5SLiam R. Howlett vma->vm_file = NULL; 2726e99668a5SLiam R. Howlett 2727e99668a5SLiam R. Howlett /* Undo any partial mapping done by a device driver. */ 2728cc8d1b09SLiam R. Howlett unmap_region(mm, &mm->mm_mt, vma, prev, next, vma->vm_start, 272968f48381SSuren Baghdasaryan vma->vm_end, true); 2730cc8d1b09SLiam R. Howlett } 2731cc674ab3SLi Zetao if (file && (vm_flags & VM_SHARED)) 2732e99668a5SLiam R. Howlett mapping_unmap_writable(file->f_mapping); 2733e99668a5SLiam R. Howlett free_vma: 2734e99668a5SLiam R. Howlett vm_area_free(vma); 2735e99668a5SLiam R. Howlett unacct_error: 2736e99668a5SLiam R. Howlett if (charged) 2737e99668a5SLiam R. Howlett vm_unacct_memory(charged); 2738e99668a5SLiam R. Howlett validate_mm(mm); 2739e99668a5SLiam R. Howlett return error; 2740e99668a5SLiam R. Howlett } 2741e99668a5SLiam R. Howlett 2742dd2283f2SYang Shi static int __vm_munmap(unsigned long start, size_t len, bool downgrade) 2743a46ef99dSLinus Torvalds { 2744a46ef99dSLinus Torvalds int ret; 2745bfce281cSAl Viro struct mm_struct *mm = current->mm; 2746897ab3e0SMike Rapoport LIST_HEAD(uf); 2747183654ceSLiam R. Howlett VMA_ITERATOR(vmi, mm, start); 2748a46ef99dSLinus Torvalds 2749d8ed45c5SMichel Lespinasse if (mmap_write_lock_killable(mm)) 2750ae798783SMichal Hocko return -EINTR; 2751ae798783SMichal Hocko 2752183654ceSLiam R. Howlett ret = do_vmi_munmap(&vmi, mm, start, len, &uf, downgrade); 2753dd2283f2SYang Shi /* 2754c1e8d7c6SMichel Lespinasse * Returning 1 indicates mmap_lock is downgraded. 2755dd2283f2SYang Shi * But 1 is not legal return value of vm_munmap() and munmap(), reset 2756dd2283f2SYang Shi * it to 0 before return. 2757dd2283f2SYang Shi */ 2758dd2283f2SYang Shi if (ret == 1) { 2759d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 2760dd2283f2SYang Shi ret = 0; 2761dd2283f2SYang Shi } else 2762d8ed45c5SMichel Lespinasse mmap_write_unlock(mm); 2763dd2283f2SYang Shi 2764897ab3e0SMike Rapoport userfaultfd_unmap_complete(mm, &uf); 2765a46ef99dSLinus Torvalds return ret; 2766a46ef99dSLinus Torvalds } 2767dd2283f2SYang Shi 2768dd2283f2SYang Shi int vm_munmap(unsigned long start, size_t len) 2769dd2283f2SYang Shi { 2770dd2283f2SYang Shi return __vm_munmap(start, len, false); 2771dd2283f2SYang Shi } 2772a46ef99dSLinus Torvalds EXPORT_SYMBOL(vm_munmap); 2773a46ef99dSLinus Torvalds 27746a6160a7SHeiko Carstens SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) 27751da177e4SLinus Torvalds { 2776ce18d171SCatalin Marinas addr = untagged_addr(addr); 2777dd2283f2SYang Shi return __vm_munmap(addr, len, true); 27781da177e4SLinus Torvalds } 27791da177e4SLinus Torvalds 2780c8d78c18SKirill A. Shutemov 2781c8d78c18SKirill A. Shutemov /* 2782c8d78c18SKirill A. Shutemov * Emulation of deprecated remap_file_pages() syscall. 2783c8d78c18SKirill A. Shutemov */ 2784c8d78c18SKirill A. Shutemov SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size, 2785c8d78c18SKirill A. Shutemov unsigned long, prot, unsigned long, pgoff, unsigned long, flags) 2786c8d78c18SKirill A. Shutemov { 2787c8d78c18SKirill A. Shutemov 2788c8d78c18SKirill A. Shutemov struct mm_struct *mm = current->mm; 2789c8d78c18SKirill A. Shutemov struct vm_area_struct *vma; 2790c8d78c18SKirill A. Shutemov unsigned long populate = 0; 2791c8d78c18SKirill A. Shutemov unsigned long ret = -EINVAL; 2792c8d78c18SKirill A. Shutemov struct file *file; 2793c8d78c18SKirill A. Shutemov 2794ee65728eSMike Rapoport pr_warn_once("%s (%d) uses deprecated remap_file_pages() syscall. See Documentation/mm/remap_file_pages.rst.\n", 2795c8d78c18SKirill A. Shutemov current->comm, current->pid); 2796c8d78c18SKirill A. Shutemov 2797c8d78c18SKirill A. Shutemov if (prot) 2798c8d78c18SKirill A. Shutemov return ret; 2799c8d78c18SKirill A. Shutemov start = start & PAGE_MASK; 2800c8d78c18SKirill A. Shutemov size = size & PAGE_MASK; 2801c8d78c18SKirill A. Shutemov 2802c8d78c18SKirill A. Shutemov if (start + size <= start) 2803c8d78c18SKirill A. Shutemov return ret; 2804c8d78c18SKirill A. Shutemov 2805c8d78c18SKirill A. Shutemov /* Does pgoff wrap? */ 2806c8d78c18SKirill A. Shutemov if (pgoff + (size >> PAGE_SHIFT) < pgoff) 2807c8d78c18SKirill A. Shutemov return ret; 2808c8d78c18SKirill A. Shutemov 2809d8ed45c5SMichel Lespinasse if (mmap_write_lock_killable(mm)) 2810dc0ef0dfSMichal Hocko return -EINTR; 2811dc0ef0dfSMichal Hocko 28129b593cb2SLiam R. Howlett vma = vma_lookup(mm, start); 2813c8d78c18SKirill A. Shutemov 2814c8d78c18SKirill A. Shutemov if (!vma || !(vma->vm_flags & VM_SHARED)) 2815c8d78c18SKirill A. Shutemov goto out; 2816c8d78c18SKirill A. Shutemov 281748f7df32SKirill A. Shutemov if (start + size > vma->vm_end) { 2818763ecb03SLiam R. Howlett VMA_ITERATOR(vmi, mm, vma->vm_end); 2819763ecb03SLiam R. Howlett struct vm_area_struct *next, *prev = vma; 282048f7df32SKirill A. Shutemov 2821763ecb03SLiam R. Howlett for_each_vma_range(vmi, next, start + size) { 282248f7df32SKirill A. Shutemov /* hole between vmas ? */ 2823763ecb03SLiam R. Howlett if (next->vm_start != prev->vm_end) 282448f7df32SKirill A. Shutemov goto out; 282548f7df32SKirill A. Shutemov 282648f7df32SKirill A. Shutemov if (next->vm_file != vma->vm_file) 282748f7df32SKirill A. Shutemov goto out; 282848f7df32SKirill A. Shutemov 282948f7df32SKirill A. Shutemov if (next->vm_flags != vma->vm_flags) 283048f7df32SKirill A. Shutemov goto out; 283148f7df32SKirill A. Shutemov 28321db43d3fSLiam Howlett if (start + size <= next->vm_end) 28331db43d3fSLiam Howlett break; 28341db43d3fSLiam Howlett 2835763ecb03SLiam R. Howlett prev = next; 283648f7df32SKirill A. Shutemov } 283748f7df32SKirill A. Shutemov 283848f7df32SKirill A. Shutemov if (!next) 2839c8d78c18SKirill A. Shutemov goto out; 2840c8d78c18SKirill A. Shutemov } 2841c8d78c18SKirill A. Shutemov 2842c8d78c18SKirill A. Shutemov prot |= vma->vm_flags & VM_READ ? PROT_READ : 0; 2843c8d78c18SKirill A. Shutemov prot |= vma->vm_flags & VM_WRITE ? PROT_WRITE : 0; 2844c8d78c18SKirill A. Shutemov prot |= vma->vm_flags & VM_EXEC ? PROT_EXEC : 0; 2845c8d78c18SKirill A. Shutemov 2846c8d78c18SKirill A. Shutemov flags &= MAP_NONBLOCK; 2847c8d78c18SKirill A. Shutemov flags |= MAP_SHARED | MAP_FIXED | MAP_POPULATE; 2848fce000b1SLiam Howlett if (vma->vm_flags & VM_LOCKED) 2849c8d78c18SKirill A. Shutemov flags |= MAP_LOCKED; 285048f7df32SKirill A. Shutemov 2851c8d78c18SKirill A. Shutemov file = get_file(vma->vm_file); 285245e55300SPeter Collingbourne ret = do_mmap(vma->vm_file, start, size, 2853897ab3e0SMike Rapoport prot, flags, pgoff, &populate, NULL); 2854c8d78c18SKirill A. Shutemov fput(file); 2855c8d78c18SKirill A. Shutemov out: 2856d8ed45c5SMichel Lespinasse mmap_write_unlock(mm); 2857c8d78c18SKirill A. Shutemov if (populate) 2858c8d78c18SKirill A. Shutemov mm_populate(ret, populate); 2859c8d78c18SKirill A. Shutemov if (!IS_ERR_VALUE(ret)) 2860c8d78c18SKirill A. Shutemov ret = 0; 2861c8d78c18SKirill A. Shutemov return ret; 2862c8d78c18SKirill A. Shutemov } 2863c8d78c18SKirill A. Shutemov 28641da177e4SLinus Torvalds /* 286527b26701SLiam R. Howlett * do_vma_munmap() - Unmap a full or partial vma. 286627b26701SLiam R. Howlett * @vmi: The vma iterator pointing at the vma 286727b26701SLiam R. Howlett * @vma: The first vma to be munmapped 286827b26701SLiam R. Howlett * @start: the start of the address to unmap 286927b26701SLiam R. Howlett * @end: The end of the address to unmap 28702e7ce7d3SLiam R. Howlett * @uf: The userfaultfd list_head 287127b26701SLiam R. Howlett * @downgrade: Attempt to downgrade or not 28722e7ce7d3SLiam R. Howlett * 287327b26701SLiam R. Howlett * Returns: 0 on success and not downgraded, 1 on success and downgraded. 287427b26701SLiam R. Howlett * unmaps a VMA mapping when the vma iterator is already in position. 287527b26701SLiam R. Howlett * Does not handle alignment. 28761da177e4SLinus Torvalds */ 287727b26701SLiam R. Howlett int do_vma_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma, 287827b26701SLiam R. Howlett unsigned long start, unsigned long end, 287927b26701SLiam R. Howlett struct list_head *uf, bool downgrade) 28802e7ce7d3SLiam R. Howlett { 28812e7ce7d3SLiam R. Howlett struct mm_struct *mm = vma->vm_mm; 28822e7ce7d3SLiam R. Howlett int ret; 28832e7ce7d3SLiam R. Howlett 288427b26701SLiam R. Howlett arch_unmap(mm, start, end); 288527b26701SLiam R. Howlett ret = do_vmi_align_munmap(vmi, vma, mm, start, end, uf, downgrade); 28862e7ce7d3SLiam R. Howlett validate_mm_mt(mm); 28872e7ce7d3SLiam R. Howlett return ret; 28882e7ce7d3SLiam R. Howlett } 28892e7ce7d3SLiam R. Howlett 28902e7ce7d3SLiam R. Howlett /* 28912e7ce7d3SLiam R. Howlett * do_brk_flags() - Increase the brk vma if the flags match. 289292fed820SLiam R. Howlett * @vmi: The vma iterator 28932e7ce7d3SLiam R. Howlett * @addr: The start address 28942e7ce7d3SLiam R. Howlett * @len: The length of the increase 28952e7ce7d3SLiam R. Howlett * @vma: The vma, 28962e7ce7d3SLiam R. Howlett * @flags: The VMA Flags 28972e7ce7d3SLiam R. Howlett * 28982e7ce7d3SLiam R. Howlett * Extend the brk VMA from addr to addr + len. If the VMA is NULL or the flags 28992e7ce7d3SLiam R. Howlett * do not match then create a new anonymous VMA. Eventually we may be able to 29002e7ce7d3SLiam R. Howlett * do some brk-specific accounting here. 29012e7ce7d3SLiam R. Howlett */ 290292fed820SLiam R. Howlett static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma, 2903763ecb03SLiam R. Howlett unsigned long addr, unsigned long len, unsigned long flags) 29041da177e4SLinus Torvalds { 29051da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 2906287051b1SLiam R. Howlett struct vma_prepare vp; 29072e7ce7d3SLiam R. Howlett 2908d4af56c5SLiam R. Howlett validate_mm_mt(mm); 29092e7ce7d3SLiam R. Howlett /* 29102e7ce7d3SLiam R. Howlett * Check against address space limits by the changed size 29112e7ce7d3SLiam R. Howlett * Note: This happens *after* clearing old mappings in some code paths. 29122e7ce7d3SLiam R. Howlett */ 291316e72e9bSDenys Vlasenko flags |= VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; 291484638335SKonstantin Khlebnikov if (!may_expand_vm(mm, flags, len >> PAGE_SHIFT)) 29151da177e4SLinus Torvalds return -ENOMEM; 29161da177e4SLinus Torvalds 29171da177e4SLinus Torvalds if (mm->map_count > sysctl_max_map_count) 29181da177e4SLinus Torvalds return -ENOMEM; 29191da177e4SLinus Torvalds 2920191c5424SAl Viro if (security_vm_enough_memory_mm(mm, len >> PAGE_SHIFT)) 29211da177e4SLinus Torvalds return -ENOMEM; 29221da177e4SLinus Torvalds 29231da177e4SLinus Torvalds /* 29242e7ce7d3SLiam R. Howlett * Expand the existing vma if possible; Note that singular lists do not 29252e7ce7d3SLiam R. Howlett * occur after forking, so the expand will only happen on new VMAs. 29261da177e4SLinus Torvalds */ 29276c28ca64SLiam Howlett if (vma && vma->vm_end == addr && !vma_policy(vma) && 29286c28ca64SLiam Howlett can_vma_merge_after(vma, flags, NULL, NULL, 29296c28ca64SLiam Howlett addr >> PAGE_SHIFT, NULL_VM_UFFD_CTX, NULL)) { 293092fed820SLiam R. Howlett if (vma_iter_prealloc(vmi)) 2931675eaca1SAlistair Popple goto unacct_fail; 293228c5609fSLiam Howlett 2933287051b1SLiam R. Howlett init_vma_prep(&vp, vma); 2934287051b1SLiam R. Howlett vma_prepare(&vp); 2935ccf1d78dSSuren Baghdasaryan vma_adjust_trans_huge(vma, vma->vm_start, addr + len, 0); 29362e7ce7d3SLiam R. Howlett vma->vm_end = addr + len; 29371c71222eSSuren Baghdasaryan vm_flags_set(vma, VM_SOFTDIRTY); 293892fed820SLiam R. Howlett vma_iter_store(vmi, vma); 29392e7ce7d3SLiam R. Howlett 2940287051b1SLiam R. Howlett vma_complete(&vp, vmi, mm); 29412e7ce7d3SLiam R. Howlett khugepaged_enter_vma(vma, flags); 29422e7ce7d3SLiam R. Howlett goto out; 29432e7ce7d3SLiam R. Howlett } 29442e7ce7d3SLiam R. Howlett 29452e7ce7d3SLiam R. Howlett /* create a vma struct for an anonymous mapping */ 29462e7ce7d3SLiam R. Howlett vma = vm_area_alloc(mm); 29472e7ce7d3SLiam R. Howlett if (!vma) 2948675eaca1SAlistair Popple goto unacct_fail; 29491da177e4SLinus Torvalds 2950bfd40eafSKirill A. Shutemov vma_set_anonymous(vma); 29511da177e4SLinus Torvalds vma->vm_start = addr; 29521da177e4SLinus Torvalds vma->vm_end = addr + len; 29532e7ce7d3SLiam R. Howlett vma->vm_pgoff = addr >> PAGE_SHIFT; 29541c71222eSSuren Baghdasaryan vm_flags_init(vma, flags); 29553ed75eb8SColy Li vma->vm_page_prot = vm_get_page_prot(flags); 295692fed820SLiam R. Howlett if (vma_iter_store_gfp(vmi, vma, GFP_KERNEL)) 29572e7ce7d3SLiam R. Howlett goto mas_store_fail; 2958d4af56c5SLiam R. Howlett 29592e7ce7d3SLiam R. Howlett mm->map_count++; 29601da177e4SLinus Torvalds out: 29613af9e859SEric B Munson perf_event_mmap(vma); 29621da177e4SLinus Torvalds mm->total_vm += len >> PAGE_SHIFT; 296384638335SKonstantin Khlebnikov mm->data_vm += len >> PAGE_SHIFT; 2964128557ffSMichel Lespinasse if (flags & VM_LOCKED) 2965ba470de4SRik van Riel mm->locked_vm += (len >> PAGE_SHIFT); 29661c71222eSSuren Baghdasaryan vm_flags_set(vma, VM_SOFTDIRTY); 2967763ecb03SLiam R. Howlett validate_mm(mm); 29685d22fc25SLinus Torvalds return 0; 2969d4af56c5SLiam R. Howlett 29702e7ce7d3SLiam R. Howlett mas_store_fail: 2971d4af56c5SLiam R. Howlett vm_area_free(vma); 2972675eaca1SAlistair Popple unacct_fail: 29732e7ce7d3SLiam R. Howlett vm_unacct_memory(len >> PAGE_SHIFT); 29742e7ce7d3SLiam R. Howlett return -ENOMEM; 29751da177e4SLinus Torvalds } 29761da177e4SLinus Torvalds 2977bb177a73SMichal Hocko int vm_brk_flags(unsigned long addr, unsigned long request, unsigned long flags) 2978e4eb1ff6SLinus Torvalds { 2979e4eb1ff6SLinus Torvalds struct mm_struct *mm = current->mm; 29802e7ce7d3SLiam R. Howlett struct vm_area_struct *vma = NULL; 2981bb177a73SMichal Hocko unsigned long len; 29825d22fc25SLinus Torvalds int ret; 2983128557ffSMichel Lespinasse bool populate; 2984897ab3e0SMike Rapoport LIST_HEAD(uf); 298592fed820SLiam R. Howlett VMA_ITERATOR(vmi, mm, addr); 2986e4eb1ff6SLinus Torvalds 2987bb177a73SMichal Hocko len = PAGE_ALIGN(request); 2988bb177a73SMichal Hocko if (len < request) 2989bb177a73SMichal Hocko return -ENOMEM; 2990bb177a73SMichal Hocko if (!len) 2991bb177a73SMichal Hocko return 0; 2992bb177a73SMichal Hocko 2993d8ed45c5SMichel Lespinasse if (mmap_write_lock_killable(mm)) 29942d6c9282SMichal Hocko return -EINTR; 29952d6c9282SMichal Hocko 29962e7ce7d3SLiam R. Howlett /* Until we need other flags, refuse anything except VM_EXEC. */ 29972e7ce7d3SLiam R. Howlett if ((flags & (~VM_EXEC)) != 0) 29982e7ce7d3SLiam R. Howlett return -EINVAL; 29992e7ce7d3SLiam R. Howlett 30002e7ce7d3SLiam R. Howlett ret = check_brk_limits(addr, len); 30012e7ce7d3SLiam R. Howlett if (ret) 30022e7ce7d3SLiam R. Howlett goto limits_failed; 30032e7ce7d3SLiam R. Howlett 3004183654ceSLiam R. Howlett ret = do_vmi_munmap(&vmi, mm, addr, len, &uf, 0); 30052e7ce7d3SLiam R. Howlett if (ret) 30062e7ce7d3SLiam R. Howlett goto munmap_failed; 30072e7ce7d3SLiam R. Howlett 300892fed820SLiam R. Howlett vma = vma_prev(&vmi); 300992fed820SLiam R. Howlett ret = do_brk_flags(&vmi, vma, addr, len, flags); 3010128557ffSMichel Lespinasse populate = ((mm->def_flags & VM_LOCKED) != 0); 3011d8ed45c5SMichel Lespinasse mmap_write_unlock(mm); 3012897ab3e0SMike Rapoport userfaultfd_unmap_complete(mm, &uf); 30135d22fc25SLinus Torvalds if (populate && !ret) 3014128557ffSMichel Lespinasse mm_populate(addr, len); 3015e4eb1ff6SLinus Torvalds return ret; 30162e7ce7d3SLiam R. Howlett 30172e7ce7d3SLiam R. Howlett munmap_failed: 30182e7ce7d3SLiam R. Howlett limits_failed: 30192e7ce7d3SLiam R. Howlett mmap_write_unlock(mm); 30202e7ce7d3SLiam R. Howlett return ret; 3021e4eb1ff6SLinus Torvalds } 302216e72e9bSDenys Vlasenko EXPORT_SYMBOL(vm_brk_flags); 302316e72e9bSDenys Vlasenko 302416e72e9bSDenys Vlasenko int vm_brk(unsigned long addr, unsigned long len) 302516e72e9bSDenys Vlasenko { 302616e72e9bSDenys Vlasenko return vm_brk_flags(addr, len, 0); 302716e72e9bSDenys Vlasenko } 3028e4eb1ff6SLinus Torvalds EXPORT_SYMBOL(vm_brk); 30291da177e4SLinus Torvalds 30301da177e4SLinus Torvalds /* Release all mmaps. */ 30311da177e4SLinus Torvalds void exit_mmap(struct mm_struct *mm) 30321da177e4SLinus Torvalds { 3033d16dfc55SPeter Zijlstra struct mmu_gather tlb; 3034ba470de4SRik van Riel struct vm_area_struct *vma; 30351da177e4SLinus Torvalds unsigned long nr_accounted = 0; 3036763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 3037763ecb03SLiam R. Howlett int count = 0; 30381da177e4SLinus Torvalds 3039d6dd61c8SJeremy Fitzhardinge /* mm's last user has gone, and its about to be pulled down */ 3040cddb8a5cSAndrea Arcangeli mmu_notifier_release(mm); 3041d6dd61c8SJeremy Fitzhardinge 3042bf3980c8SSuren Baghdasaryan mmap_read_lock(mm); 30439480c53eSJeremy Fitzhardinge arch_exit_mmap(mm); 30449480c53eSJeremy Fitzhardinge 3045763ecb03SLiam R. Howlett vma = mas_find(&mas, ULONG_MAX); 304664591e86SSuren Baghdasaryan if (!vma) { 304764591e86SSuren Baghdasaryan /* Can happen if dup_mmap() received an OOM */ 3048bf3980c8SSuren Baghdasaryan mmap_read_unlock(mm); 30499480c53eSJeremy Fitzhardinge return; 305064591e86SSuren Baghdasaryan } 30519480c53eSJeremy Fitzhardinge 30521da177e4SLinus Torvalds lru_add_drain(); 30531da177e4SLinus Torvalds flush_cache_mm(mm); 3054d8b45053SWill Deacon tlb_gather_mmu_fullmm(&tlb, mm); 3055901608d9SOleg Nesterov /* update_hiwater_rss(mm) here? but nobody should be looking */ 3056763ecb03SLiam R. Howlett /* Use ULONG_MAX here to ensure all VMAs in the mm are unmapped */ 305768f48381SSuren Baghdasaryan unmap_vmas(&tlb, &mm->mm_mt, vma, 0, ULONG_MAX, false); 3058bf3980c8SSuren Baghdasaryan mmap_read_unlock(mm); 3059bf3980c8SSuren Baghdasaryan 3060bf3980c8SSuren Baghdasaryan /* 3061bf3980c8SSuren Baghdasaryan * Set MMF_OOM_SKIP to hide this task from the oom killer/reaper 3062b3541d91SSuren Baghdasaryan * because the memory has been already freed. 3063bf3980c8SSuren Baghdasaryan */ 3064bf3980c8SSuren Baghdasaryan set_bit(MMF_OOM_SKIP, &mm->flags); 3065bf3980c8SSuren Baghdasaryan mmap_write_lock(mm); 3066763ecb03SLiam R. Howlett free_pgtables(&tlb, &mm->mm_mt, vma, FIRST_USER_ADDRESS, 3067763ecb03SLiam R. Howlett USER_PGTABLES_CEILING); 3068ae8eba8bSWill Deacon tlb_finish_mmu(&tlb); 30691da177e4SLinus Torvalds 3070763ecb03SLiam R. Howlett /* 3071763ecb03SLiam R. Howlett * Walk the list again, actually closing and freeing it, with preemption 3072763ecb03SLiam R. Howlett * enabled, without holding any MM locks besides the unreachable 3073763ecb03SLiam R. Howlett * mmap_write_lock. 3074763ecb03SLiam R. Howlett */ 3075763ecb03SLiam R. Howlett do { 30764f74d2c8SLinus Torvalds if (vma->vm_flags & VM_ACCOUNT) 30774f74d2c8SLinus Torvalds nr_accounted += vma_pages(vma); 3078763ecb03SLiam R. Howlett remove_vma(vma); 3079763ecb03SLiam R. Howlett count++; 30800a3b3c25SPaul E. McKenney cond_resched(); 3081763ecb03SLiam R. Howlett } while ((vma = mas_find(&mas, ULONG_MAX)) != NULL); 3082763ecb03SLiam R. Howlett 3083763ecb03SLiam R. Howlett BUG_ON(count != mm->map_count); 3084d4af56c5SLiam R. Howlett 3085d4af56c5SLiam R. Howlett trace_exit_mmap(mm); 3086d4af56c5SLiam R. Howlett __mt_destroy(&mm->mm_mt); 308764591e86SSuren Baghdasaryan mmap_write_unlock(mm); 30884f74d2c8SLinus Torvalds vm_unacct_memory(nr_accounted); 30891da177e4SLinus Torvalds } 30901da177e4SLinus Torvalds 30911da177e4SLinus Torvalds /* Insert vm structure into process list sorted by address 30921da177e4SLinus Torvalds * and into the inode's i_mmap tree. If vm_file is non-NULL 3093c8c06efaSDavidlohr Bueso * then i_mmap_rwsem is taken here. 30941da177e4SLinus Torvalds */ 30951da177e4SLinus Torvalds int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) 30961da177e4SLinus Torvalds { 3097d4af56c5SLiam R. Howlett unsigned long charged = vma_pages(vma); 30981da177e4SLinus Torvalds 3099d4af56c5SLiam R. Howlett 3100d0601a50SLiam R. Howlett if (find_vma_intersection(mm, vma->vm_start, vma->vm_end)) 3101c9d13f5fSChen Gang return -ENOMEM; 3102d4af56c5SLiam R. Howlett 3103c9d13f5fSChen Gang if ((vma->vm_flags & VM_ACCOUNT) && 3104d4af56c5SLiam R. Howlett security_vm_enough_memory_mm(mm, charged)) 3105c9d13f5fSChen Gang return -ENOMEM; 3106c9d13f5fSChen Gang 31071da177e4SLinus Torvalds /* 31081da177e4SLinus Torvalds * The vm_pgoff of a purely anonymous vma should be irrelevant 31091da177e4SLinus Torvalds * until its first write fault, when page's anon_vma and index 31101da177e4SLinus Torvalds * are set. But now set the vm_pgoff it will almost certainly 31111da177e4SLinus Torvalds * end up with (unless mremap moves it elsewhere before that 31121da177e4SLinus Torvalds * first wfault), so /proc/pid/maps tells a consistent story. 31131da177e4SLinus Torvalds * 31141da177e4SLinus Torvalds * By setting it to reflect the virtual start address of the 31151da177e4SLinus Torvalds * vma, merges and splits can happen in a seamless way, just 31161da177e4SLinus Torvalds * using the existing file pgoff checks and manipulations. 31178332326eSLiao Pingfang * Similarly in do_mmap and in do_brk_flags. 31181da177e4SLinus Torvalds */ 31198a9cc3b5SOleg Nesterov if (vma_is_anonymous(vma)) { 31201da177e4SLinus Torvalds BUG_ON(vma->anon_vma); 31211da177e4SLinus Torvalds vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT; 31221da177e4SLinus Torvalds } 31232b144498SSrikar Dronamraju 3124763ecb03SLiam R. Howlett if (vma_link(mm, vma)) { 3125d4af56c5SLiam R. Howlett vm_unacct_memory(charged); 3126d4af56c5SLiam R. Howlett return -ENOMEM; 3127d4af56c5SLiam R. Howlett } 3128d4af56c5SLiam R. Howlett 31291da177e4SLinus Torvalds return 0; 31301da177e4SLinus Torvalds } 31311da177e4SLinus Torvalds 31321da177e4SLinus Torvalds /* 31331da177e4SLinus Torvalds * Copy the vma structure to a new location in the same mm, 31341da177e4SLinus Torvalds * prior to moving page table entries, to effect an mremap move. 31351da177e4SLinus Torvalds */ 31361da177e4SLinus Torvalds struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, 313738a76013SMichel Lespinasse unsigned long addr, unsigned long len, pgoff_t pgoff, 313838a76013SMichel Lespinasse bool *need_rmap_locks) 31391da177e4SLinus Torvalds { 31401da177e4SLinus Torvalds struct vm_area_struct *vma = *vmap; 31411da177e4SLinus Torvalds unsigned long vma_start = vma->vm_start; 31421da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 31431da177e4SLinus Torvalds struct vm_area_struct *new_vma, *prev; 3144948f017bSAndrea Arcangeli bool faulted_in_anon_vma = true; 3145076f16bfSLiam R. Howlett VMA_ITERATOR(vmi, mm, addr); 31461da177e4SLinus Torvalds 3147d4af56c5SLiam R. Howlett validate_mm_mt(mm); 31481da177e4SLinus Torvalds /* 31491da177e4SLinus Torvalds * If anonymous vma has not yet been faulted, update new pgoff 31501da177e4SLinus Torvalds * to match new location, to increase its chance of merging. 31511da177e4SLinus Torvalds */ 3152ce75799bSOleg Nesterov if (unlikely(vma_is_anonymous(vma) && !vma->anon_vma)) { 31531da177e4SLinus Torvalds pgoff = addr >> PAGE_SHIFT; 3154948f017bSAndrea Arcangeli faulted_in_anon_vma = false; 3155948f017bSAndrea Arcangeli } 31561da177e4SLinus Torvalds 3157763ecb03SLiam R. Howlett new_vma = find_vma_prev(mm, addr, &prev); 3158763ecb03SLiam R. Howlett if (new_vma && new_vma->vm_start < addr + len) 31596597d783SHugh Dickins return NULL; /* should never get here */ 3160524e00b3SLiam R. Howlett 31619760ebffSLiam R. Howlett new_vma = vma_merge(&vmi, mm, prev, addr, addr + len, vma->vm_flags, 316219a809afSAndrea Arcangeli vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma), 31635c26f6acSSuren Baghdasaryan vma->vm_userfaultfd_ctx, anon_vma_name(vma)); 31641da177e4SLinus Torvalds if (new_vma) { 31651da177e4SLinus Torvalds /* 31661da177e4SLinus Torvalds * Source vma may have been merged into new_vma 31671da177e4SLinus Torvalds */ 3168948f017bSAndrea Arcangeli if (unlikely(vma_start >= new_vma->vm_start && 3169948f017bSAndrea Arcangeli vma_start < new_vma->vm_end)) { 3170948f017bSAndrea Arcangeli /* 3171948f017bSAndrea Arcangeli * The only way we can get a vma_merge with 3172948f017bSAndrea Arcangeli * self during an mremap is if the vma hasn't 3173948f017bSAndrea Arcangeli * been faulted in yet and we were allowed to 3174948f017bSAndrea Arcangeli * reset the dst vma->vm_pgoff to the 3175948f017bSAndrea Arcangeli * destination address of the mremap to allow 3176948f017bSAndrea Arcangeli * the merge to happen. mremap must change the 3177948f017bSAndrea Arcangeli * vm_pgoff linearity between src and dst vmas 3178948f017bSAndrea Arcangeli * (in turn preventing a vma_merge) to be 3179948f017bSAndrea Arcangeli * safe. It is only safe to keep the vm_pgoff 3180948f017bSAndrea Arcangeli * linear if there are no pages mapped yet. 3181948f017bSAndrea Arcangeli */ 318281d1b09cSSasha Levin VM_BUG_ON_VMA(faulted_in_anon_vma, new_vma); 318338a76013SMichel Lespinasse *vmap = vma = new_vma; 3184108d6642SMichel Lespinasse } 318538a76013SMichel Lespinasse *need_rmap_locks = (new_vma->vm_pgoff <= vma->vm_pgoff); 31861da177e4SLinus Torvalds } else { 31873928d4f5SLinus Torvalds new_vma = vm_area_dup(vma); 3188e3975891SChen Gang if (!new_vma) 3189e3975891SChen Gang goto out; 31901da177e4SLinus Torvalds new_vma->vm_start = addr; 31911da177e4SLinus Torvalds new_vma->vm_end = addr + len; 31921da177e4SLinus Torvalds new_vma->vm_pgoff = pgoff; 3193ef0855d3SOleg Nesterov if (vma_dup_policy(vma, new_vma)) 3194523d4e20SMichel Lespinasse goto out_free_vma; 3195523d4e20SMichel Lespinasse if (anon_vma_clone(new_vma, vma)) 3196523d4e20SMichel Lespinasse goto out_free_mempol; 3197e9714acfSKonstantin Khlebnikov if (new_vma->vm_file) 31981da177e4SLinus Torvalds get_file(new_vma->vm_file); 31991da177e4SLinus Torvalds if (new_vma->vm_ops && new_vma->vm_ops->open) 32001da177e4SLinus Torvalds new_vma->vm_ops->open(new_vma); 3201d6ac235dSSuren Baghdasaryan vma_start_write(new_vma); 3202763ecb03SLiam R. Howlett if (vma_link(mm, new_vma)) 3203524e00b3SLiam R. Howlett goto out_vma_link; 320438a76013SMichel Lespinasse *need_rmap_locks = false; 32051da177e4SLinus Torvalds } 3206d4af56c5SLiam R. Howlett validate_mm_mt(mm); 32071da177e4SLinus Torvalds return new_vma; 32085beb4930SRik van Riel 3209524e00b3SLiam R. Howlett out_vma_link: 3210524e00b3SLiam R. Howlett if (new_vma->vm_ops && new_vma->vm_ops->close) 3211524e00b3SLiam R. Howlett new_vma->vm_ops->close(new_vma); 321292b73996SLiam Howlett 321392b73996SLiam Howlett if (new_vma->vm_file) 321492b73996SLiam Howlett fput(new_vma->vm_file); 321592b73996SLiam Howlett 321692b73996SLiam Howlett unlink_anon_vmas(new_vma); 32175beb4930SRik van Riel out_free_mempol: 3218ef0855d3SOleg Nesterov mpol_put(vma_policy(new_vma)); 32195beb4930SRik van Riel out_free_vma: 32203928d4f5SLinus Torvalds vm_area_free(new_vma); 3221e3975891SChen Gang out: 3222d4af56c5SLiam R. Howlett validate_mm_mt(mm); 32235beb4930SRik van Riel return NULL; 32241da177e4SLinus Torvalds } 3225119f657cSakpm@osdl.org 3226119f657cSakpm@osdl.org /* 3227119f657cSakpm@osdl.org * Return true if the calling process may expand its vm space by the passed 3228119f657cSakpm@osdl.org * number of pages 3229119f657cSakpm@osdl.org */ 323084638335SKonstantin Khlebnikov bool may_expand_vm(struct mm_struct *mm, vm_flags_t flags, unsigned long npages) 3231119f657cSakpm@osdl.org { 323284638335SKonstantin Khlebnikov if (mm->total_vm + npages > rlimit(RLIMIT_AS) >> PAGE_SHIFT) 323384638335SKonstantin Khlebnikov return false; 3234119f657cSakpm@osdl.org 3235d977d56cSKonstantin Khlebnikov if (is_data_mapping(flags) && 3236d977d56cSKonstantin Khlebnikov mm->data_vm + npages > rlimit(RLIMIT_DATA) >> PAGE_SHIFT) { 3237f4fcd558SKonstantin Khlebnikov /* Workaround for Valgrind */ 3238f4fcd558SKonstantin Khlebnikov if (rlimit(RLIMIT_DATA) == 0 && 3239f4fcd558SKonstantin Khlebnikov mm->data_vm + npages <= rlimit_max(RLIMIT_DATA) >> PAGE_SHIFT) 3240f4fcd558SKonstantin Khlebnikov return true; 324157a7702bSDavid Woodhouse 324257a7702bSDavid Woodhouse pr_warn_once("%s (%d): VmData %lu exceed data ulimit %lu. Update limits%s.\n", 3243d977d56cSKonstantin Khlebnikov current->comm, current->pid, 3244d977d56cSKonstantin Khlebnikov (mm->data_vm + npages) << PAGE_SHIFT, 324557a7702bSDavid Woodhouse rlimit(RLIMIT_DATA), 324657a7702bSDavid Woodhouse ignore_rlimit_data ? "" : " or use boot option ignore_rlimit_data"); 324757a7702bSDavid Woodhouse 324857a7702bSDavid Woodhouse if (!ignore_rlimit_data) 3249d977d56cSKonstantin Khlebnikov return false; 3250d977d56cSKonstantin Khlebnikov } 3251119f657cSakpm@osdl.org 325284638335SKonstantin Khlebnikov return true; 325384638335SKonstantin Khlebnikov } 325484638335SKonstantin Khlebnikov 325584638335SKonstantin Khlebnikov void vm_stat_account(struct mm_struct *mm, vm_flags_t flags, long npages) 325684638335SKonstantin Khlebnikov { 32577866076bSPeng Liu WRITE_ONCE(mm->total_vm, READ_ONCE(mm->total_vm)+npages); 325884638335SKonstantin Khlebnikov 3259d977d56cSKonstantin Khlebnikov if (is_exec_mapping(flags)) 326084638335SKonstantin Khlebnikov mm->exec_vm += npages; 3261d977d56cSKonstantin Khlebnikov else if (is_stack_mapping(flags)) 326284638335SKonstantin Khlebnikov mm->stack_vm += npages; 3263d977d56cSKonstantin Khlebnikov else if (is_data_mapping(flags)) 326484638335SKonstantin Khlebnikov mm->data_vm += npages; 3265119f657cSakpm@osdl.org } 3266fa5dc22fSRoland McGrath 3267b3ec9f33SSouptick Joarder static vm_fault_t special_mapping_fault(struct vm_fault *vmf); 3268a62c34bdSAndy Lutomirski 3269a62c34bdSAndy Lutomirski /* 3270a62c34bdSAndy Lutomirski * Having a close hook prevents vma merging regardless of flags. 3271a62c34bdSAndy Lutomirski */ 3272a62c34bdSAndy Lutomirski static void special_mapping_close(struct vm_area_struct *vma) 3273a62c34bdSAndy Lutomirski { 3274a62c34bdSAndy Lutomirski } 3275a62c34bdSAndy Lutomirski 3276a62c34bdSAndy Lutomirski static const char *special_mapping_name(struct vm_area_struct *vma) 3277a62c34bdSAndy Lutomirski { 3278a62c34bdSAndy Lutomirski return ((struct vm_special_mapping *)vma->vm_private_data)->name; 3279a62c34bdSAndy Lutomirski } 3280a62c34bdSAndy Lutomirski 328114d07113SBrian Geffon static int special_mapping_mremap(struct vm_area_struct *new_vma) 3282b059a453SDmitry Safonov { 3283b059a453SDmitry Safonov struct vm_special_mapping *sm = new_vma->vm_private_data; 3284b059a453SDmitry Safonov 3285280e87e9SDmitry Safonov if (WARN_ON_ONCE(current->mm != new_vma->vm_mm)) 3286280e87e9SDmitry Safonov return -EFAULT; 3287280e87e9SDmitry Safonov 3288b059a453SDmitry Safonov if (sm->mremap) 3289b059a453SDmitry Safonov return sm->mremap(sm, new_vma); 3290280e87e9SDmitry Safonov 3291b059a453SDmitry Safonov return 0; 3292b059a453SDmitry Safonov } 3293b059a453SDmitry Safonov 3294871402e0SDmitry Safonov static int special_mapping_split(struct vm_area_struct *vma, unsigned long addr) 3295871402e0SDmitry Safonov { 3296871402e0SDmitry Safonov /* 3297871402e0SDmitry Safonov * Forbid splitting special mappings - kernel has expectations over 3298871402e0SDmitry Safonov * the number of pages in mapping. Together with VM_DONTEXPAND 3299871402e0SDmitry Safonov * the size of vma should stay the same over the special mapping's 3300871402e0SDmitry Safonov * lifetime. 3301871402e0SDmitry Safonov */ 3302871402e0SDmitry Safonov return -EINVAL; 3303871402e0SDmitry Safonov } 3304871402e0SDmitry Safonov 3305a62c34bdSAndy Lutomirski static const struct vm_operations_struct special_mapping_vmops = { 3306a62c34bdSAndy Lutomirski .close = special_mapping_close, 3307a62c34bdSAndy Lutomirski .fault = special_mapping_fault, 3308b059a453SDmitry Safonov .mremap = special_mapping_mremap, 3309a62c34bdSAndy Lutomirski .name = special_mapping_name, 3310af34ebebSDmitry Safonov /* vDSO code relies that VVAR can't be accessed remotely */ 3311af34ebebSDmitry Safonov .access = NULL, 3312871402e0SDmitry Safonov .may_split = special_mapping_split, 3313a62c34bdSAndy Lutomirski }; 3314a62c34bdSAndy Lutomirski 3315a62c34bdSAndy Lutomirski static const struct vm_operations_struct legacy_special_mapping_vmops = { 3316a62c34bdSAndy Lutomirski .close = special_mapping_close, 3317a62c34bdSAndy Lutomirski .fault = special_mapping_fault, 3318a62c34bdSAndy Lutomirski }; 3319fa5dc22fSRoland McGrath 3320b3ec9f33SSouptick Joarder static vm_fault_t special_mapping_fault(struct vm_fault *vmf) 3321fa5dc22fSRoland McGrath { 332211bac800SDave Jiang struct vm_area_struct *vma = vmf->vma; 3323b1d0e4f5SNick Piggin pgoff_t pgoff; 3324fa5dc22fSRoland McGrath struct page **pages; 3325fa5dc22fSRoland McGrath 3326f872f540SAndy Lutomirski if (vma->vm_ops == &legacy_special_mapping_vmops) { 3327a62c34bdSAndy Lutomirski pages = vma->vm_private_data; 3328f872f540SAndy Lutomirski } else { 3329f872f540SAndy Lutomirski struct vm_special_mapping *sm = vma->vm_private_data; 3330f872f540SAndy Lutomirski 3331f872f540SAndy Lutomirski if (sm->fault) 333211bac800SDave Jiang return sm->fault(sm, vmf->vma, vmf); 3333f872f540SAndy Lutomirski 3334f872f540SAndy Lutomirski pages = sm->pages; 3335f872f540SAndy Lutomirski } 3336a62c34bdSAndy Lutomirski 33378a9cc3b5SOleg Nesterov for (pgoff = vmf->pgoff; pgoff && *pages; ++pages) 3338b1d0e4f5SNick Piggin pgoff--; 3339fa5dc22fSRoland McGrath 3340fa5dc22fSRoland McGrath if (*pages) { 3341fa5dc22fSRoland McGrath struct page *page = *pages; 3342fa5dc22fSRoland McGrath get_page(page); 3343b1d0e4f5SNick Piggin vmf->page = page; 3344b1d0e4f5SNick Piggin return 0; 3345fa5dc22fSRoland McGrath } 3346fa5dc22fSRoland McGrath 3347b1d0e4f5SNick Piggin return VM_FAULT_SIGBUS; 3348fa5dc22fSRoland McGrath } 3349fa5dc22fSRoland McGrath 3350a62c34bdSAndy Lutomirski static struct vm_area_struct *__install_special_mapping( 3351a62c34bdSAndy Lutomirski struct mm_struct *mm, 3352fa5dc22fSRoland McGrath unsigned long addr, unsigned long len, 335327f28b97SChen Gang unsigned long vm_flags, void *priv, 335427f28b97SChen Gang const struct vm_operations_struct *ops) 3355fa5dc22fSRoland McGrath { 3356462e635eSTavis Ormandy int ret; 3357fa5dc22fSRoland McGrath struct vm_area_struct *vma; 3358fa5dc22fSRoland McGrath 3359d4af56c5SLiam R. Howlett validate_mm_mt(mm); 3360490fc053SLinus Torvalds vma = vm_area_alloc(mm); 3361fa5dc22fSRoland McGrath if (unlikely(vma == NULL)) 33623935ed6aSStefani Seibold return ERR_PTR(-ENOMEM); 3363fa5dc22fSRoland McGrath 3364fa5dc22fSRoland McGrath vma->vm_start = addr; 3365fa5dc22fSRoland McGrath vma->vm_end = addr + len; 3366fa5dc22fSRoland McGrath 3367e430a95aSSuren Baghdasaryan vm_flags_init(vma, (vm_flags | mm->def_flags | 3368e430a95aSSuren Baghdasaryan VM_DONTEXPAND | VM_SOFTDIRTY) & ~VM_LOCKED_MASK); 33693ed75eb8SColy Li vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); 3370fa5dc22fSRoland McGrath 3371a62c34bdSAndy Lutomirski vma->vm_ops = ops; 3372a62c34bdSAndy Lutomirski vma->vm_private_data = priv; 3373fa5dc22fSRoland McGrath 3374462e635eSTavis Ormandy ret = insert_vm_struct(mm, vma); 3375462e635eSTavis Ormandy if (ret) 3376462e635eSTavis Ormandy goto out; 3377fa5dc22fSRoland McGrath 337884638335SKonstantin Khlebnikov vm_stat_account(mm, vma->vm_flags, len >> PAGE_SHIFT); 3379fa5dc22fSRoland McGrath 3380cdd6c482SIngo Molnar perf_event_mmap(vma); 3381089dd79dSPeter Zijlstra 3382d4af56c5SLiam R. Howlett validate_mm_mt(mm); 33833935ed6aSStefani Seibold return vma; 3384462e635eSTavis Ormandy 3385462e635eSTavis Ormandy out: 33863928d4f5SLinus Torvalds vm_area_free(vma); 3387d4af56c5SLiam R. Howlett validate_mm_mt(mm); 33883935ed6aSStefani Seibold return ERR_PTR(ret); 33893935ed6aSStefani Seibold } 33903935ed6aSStefani Seibold 33912eefd878SDmitry Safonov bool vma_is_special_mapping(const struct vm_area_struct *vma, 33922eefd878SDmitry Safonov const struct vm_special_mapping *sm) 33932eefd878SDmitry Safonov { 33942eefd878SDmitry Safonov return vma->vm_private_data == sm && 33952eefd878SDmitry Safonov (vma->vm_ops == &special_mapping_vmops || 33962eefd878SDmitry Safonov vma->vm_ops == &legacy_special_mapping_vmops); 33972eefd878SDmitry Safonov } 33982eefd878SDmitry Safonov 3399a62c34bdSAndy Lutomirski /* 3400c1e8d7c6SMichel Lespinasse * Called with mm->mmap_lock held for writing. 3401a62c34bdSAndy Lutomirski * Insert a new vma covering the given region, with the given flags. 3402a62c34bdSAndy Lutomirski * Its pages are supplied by the given array of struct page *. 3403a62c34bdSAndy Lutomirski * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated. 3404a62c34bdSAndy Lutomirski * The region past the last page supplied will always produce SIGBUS. 3405a62c34bdSAndy Lutomirski * The array pointer and the pages it points to are assumed to stay alive 3406a62c34bdSAndy Lutomirski * for as long as this mapping might exist. 3407a62c34bdSAndy Lutomirski */ 3408a62c34bdSAndy Lutomirski struct vm_area_struct *_install_special_mapping( 3409a62c34bdSAndy Lutomirski struct mm_struct *mm, 3410a62c34bdSAndy Lutomirski unsigned long addr, unsigned long len, 3411a62c34bdSAndy Lutomirski unsigned long vm_flags, const struct vm_special_mapping *spec) 3412a62c34bdSAndy Lutomirski { 341327f28b97SChen Gang return __install_special_mapping(mm, addr, len, vm_flags, (void *)spec, 341427f28b97SChen Gang &special_mapping_vmops); 3415a62c34bdSAndy Lutomirski } 3416a62c34bdSAndy Lutomirski 34173935ed6aSStefani Seibold int install_special_mapping(struct mm_struct *mm, 34183935ed6aSStefani Seibold unsigned long addr, unsigned long len, 34193935ed6aSStefani Seibold unsigned long vm_flags, struct page **pages) 34203935ed6aSStefani Seibold { 3421a62c34bdSAndy Lutomirski struct vm_area_struct *vma = __install_special_mapping( 342227f28b97SChen Gang mm, addr, len, vm_flags, (void *)pages, 342327f28b97SChen Gang &legacy_special_mapping_vmops); 34243935ed6aSStefani Seibold 342514bd5b45SDuan Jiong return PTR_ERR_OR_ZERO(vma); 3426fa5dc22fSRoland McGrath } 34277906d00cSAndrea Arcangeli 34287906d00cSAndrea Arcangeli static DEFINE_MUTEX(mm_all_locks_mutex); 34297906d00cSAndrea Arcangeli 3430454ed842SPeter Zijlstra static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma) 34317906d00cSAndrea Arcangeli { 3432f808c13fSDavidlohr Bueso if (!test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_root.rb_node)) { 34337906d00cSAndrea Arcangeli /* 34347906d00cSAndrea Arcangeli * The LSB of head.next can't change from under us 34357906d00cSAndrea Arcangeli * because we hold the mm_all_locks_mutex. 34367906d00cSAndrea Arcangeli */ 3437da1c55f1SMichel Lespinasse down_write_nest_lock(&anon_vma->root->rwsem, &mm->mmap_lock); 34387906d00cSAndrea Arcangeli /* 34397906d00cSAndrea Arcangeli * We can safely modify head.next after taking the 34405a505085SIngo Molnar * anon_vma->root->rwsem. If some other vma in this mm shares 34417906d00cSAndrea Arcangeli * the same anon_vma we won't take it again. 34427906d00cSAndrea Arcangeli * 34437906d00cSAndrea Arcangeli * No need of atomic instructions here, head.next 34447906d00cSAndrea Arcangeli * can't change from under us thanks to the 34455a505085SIngo Molnar * anon_vma->root->rwsem. 34467906d00cSAndrea Arcangeli */ 34477906d00cSAndrea Arcangeli if (__test_and_set_bit(0, (unsigned long *) 3448f808c13fSDavidlohr Bueso &anon_vma->root->rb_root.rb_root.rb_node)) 34497906d00cSAndrea Arcangeli BUG(); 34507906d00cSAndrea Arcangeli } 34517906d00cSAndrea Arcangeli } 34527906d00cSAndrea Arcangeli 3453454ed842SPeter Zijlstra static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping) 34547906d00cSAndrea Arcangeli { 34557906d00cSAndrea Arcangeli if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { 34567906d00cSAndrea Arcangeli /* 34577906d00cSAndrea Arcangeli * AS_MM_ALL_LOCKS can't change from under us because 34587906d00cSAndrea Arcangeli * we hold the mm_all_locks_mutex. 34597906d00cSAndrea Arcangeli * 34607906d00cSAndrea Arcangeli * Operations on ->flags have to be atomic because 34617906d00cSAndrea Arcangeli * even if AS_MM_ALL_LOCKS is stable thanks to the 34627906d00cSAndrea Arcangeli * mm_all_locks_mutex, there may be other cpus 34637906d00cSAndrea Arcangeli * changing other bitflags in parallel to us. 34647906d00cSAndrea Arcangeli */ 34657906d00cSAndrea Arcangeli if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags)) 34667906d00cSAndrea Arcangeli BUG(); 3467da1c55f1SMichel Lespinasse down_write_nest_lock(&mapping->i_mmap_rwsem, &mm->mmap_lock); 34687906d00cSAndrea Arcangeli } 34697906d00cSAndrea Arcangeli } 34707906d00cSAndrea Arcangeli 34717906d00cSAndrea Arcangeli /* 34727906d00cSAndrea Arcangeli * This operation locks against the VM for all pte/vma/mm related 34737906d00cSAndrea Arcangeli * operations that could ever happen on a certain mm. This includes 34747906d00cSAndrea Arcangeli * vmtruncate, try_to_unmap, and all page faults. 34757906d00cSAndrea Arcangeli * 3476c1e8d7c6SMichel Lespinasse * The caller must take the mmap_lock in write mode before calling 34777906d00cSAndrea Arcangeli * mm_take_all_locks(). The caller isn't allowed to release the 3478c1e8d7c6SMichel Lespinasse * mmap_lock until mm_drop_all_locks() returns. 34797906d00cSAndrea Arcangeli * 3480c1e8d7c6SMichel Lespinasse * mmap_lock in write mode is required in order to block all operations 34817906d00cSAndrea Arcangeli * that could modify pagetables and free pages without need of 348227ba0644SKirill A. Shutemov * altering the vma layout. It's also needed in write mode to avoid new 34837906d00cSAndrea Arcangeli * anon_vmas to be associated with existing vmas. 34847906d00cSAndrea Arcangeli * 34857906d00cSAndrea Arcangeli * A single task can't take more than one mm_take_all_locks() in a row 34867906d00cSAndrea Arcangeli * or it would deadlock. 34877906d00cSAndrea Arcangeli * 3488bf181b9fSMichel Lespinasse * The LSB in anon_vma->rb_root.rb_node and the AS_MM_ALL_LOCKS bitflag in 34897906d00cSAndrea Arcangeli * mapping->flags avoid to take the same lock twice, if more than one 34907906d00cSAndrea Arcangeli * vma in this mm is backed by the same anon_vma or address_space. 34917906d00cSAndrea Arcangeli * 349288f306b6SKirill A. Shutemov * We take locks in following order, accordingly to comment at beginning 349388f306b6SKirill A. Shutemov * of mm/rmap.c: 349488f306b6SKirill A. Shutemov * - all hugetlbfs_i_mmap_rwsem_key locks (aka mapping->i_mmap_rwsem for 349588f306b6SKirill A. Shutemov * hugetlb mapping); 349688f306b6SKirill A. Shutemov * - all i_mmap_rwsem locks; 349788f306b6SKirill A. Shutemov * - all anon_vma->rwseml 349888f306b6SKirill A. Shutemov * 349988f306b6SKirill A. Shutemov * We can take all locks within these types randomly because the VM code 350088f306b6SKirill A. Shutemov * doesn't nest them and we protected from parallel mm_take_all_locks() by 350188f306b6SKirill A. Shutemov * mm_all_locks_mutex. 35027906d00cSAndrea Arcangeli * 35037906d00cSAndrea Arcangeli * mm_take_all_locks() and mm_drop_all_locks are expensive operations 35047906d00cSAndrea Arcangeli * that may have to take thousand of locks. 35057906d00cSAndrea Arcangeli * 35067906d00cSAndrea Arcangeli * mm_take_all_locks() can fail if it's interrupted by signals. 35077906d00cSAndrea Arcangeli */ 35087906d00cSAndrea Arcangeli int mm_take_all_locks(struct mm_struct *mm) 35097906d00cSAndrea Arcangeli { 35107906d00cSAndrea Arcangeli struct vm_area_struct *vma; 35115beb4930SRik van Riel struct anon_vma_chain *avc; 3512763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 35137906d00cSAndrea Arcangeli 3514325bca1fSRolf Eike Beer mmap_assert_write_locked(mm); 35157906d00cSAndrea Arcangeli 35167906d00cSAndrea Arcangeli mutex_lock(&mm_all_locks_mutex); 35177906d00cSAndrea Arcangeli 3518763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 35197906d00cSAndrea Arcangeli if (signal_pending(current)) 35207906d00cSAndrea Arcangeli goto out_unlock; 352188f306b6SKirill A. Shutemov if (vma->vm_file && vma->vm_file->f_mapping && 352288f306b6SKirill A. Shutemov is_vm_hugetlb_page(vma)) 352388f306b6SKirill A. Shutemov vm_lock_mapping(mm, vma->vm_file->f_mapping); 352488f306b6SKirill A. Shutemov } 352588f306b6SKirill A. Shutemov 3526763ecb03SLiam R. Howlett mas_set(&mas, 0); 3527763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 352888f306b6SKirill A. Shutemov if (signal_pending(current)) 352988f306b6SKirill A. Shutemov goto out_unlock; 353088f306b6SKirill A. Shutemov if (vma->vm_file && vma->vm_file->f_mapping && 353188f306b6SKirill A. Shutemov !is_vm_hugetlb_page(vma)) 3532454ed842SPeter Zijlstra vm_lock_mapping(mm, vma->vm_file->f_mapping); 35337906d00cSAndrea Arcangeli } 35347cd5a02fSPeter Zijlstra 3535763ecb03SLiam R. Howlett mas_set(&mas, 0); 3536763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 35377cd5a02fSPeter Zijlstra if (signal_pending(current)) 35387cd5a02fSPeter Zijlstra goto out_unlock; 35397cd5a02fSPeter Zijlstra if (vma->anon_vma) 35405beb4930SRik van Riel list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 35415beb4930SRik van Riel vm_lock_anon_vma(mm, avc->anon_vma); 35427cd5a02fSPeter Zijlstra } 35437cd5a02fSPeter Zijlstra 3544584cff54SKautuk Consul return 0; 35457906d00cSAndrea Arcangeli 35467906d00cSAndrea Arcangeli out_unlock: 35477906d00cSAndrea Arcangeli mm_drop_all_locks(mm); 3548584cff54SKautuk Consul return -EINTR; 35497906d00cSAndrea Arcangeli } 35507906d00cSAndrea Arcangeli 35517906d00cSAndrea Arcangeli static void vm_unlock_anon_vma(struct anon_vma *anon_vma) 35527906d00cSAndrea Arcangeli { 3553f808c13fSDavidlohr Bueso if (test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_root.rb_node)) { 35547906d00cSAndrea Arcangeli /* 35557906d00cSAndrea Arcangeli * The LSB of head.next can't change to 0 from under 35567906d00cSAndrea Arcangeli * us because we hold the mm_all_locks_mutex. 35577906d00cSAndrea Arcangeli * 35587906d00cSAndrea Arcangeli * We must however clear the bitflag before unlocking 3559bf181b9fSMichel Lespinasse * the vma so the users using the anon_vma->rb_root will 35607906d00cSAndrea Arcangeli * never see our bitflag. 35617906d00cSAndrea Arcangeli * 35627906d00cSAndrea Arcangeli * No need of atomic instructions here, head.next 35637906d00cSAndrea Arcangeli * can't change from under us until we release the 35645a505085SIngo Molnar * anon_vma->root->rwsem. 35657906d00cSAndrea Arcangeli */ 35667906d00cSAndrea Arcangeli if (!__test_and_clear_bit(0, (unsigned long *) 3567f808c13fSDavidlohr Bueso &anon_vma->root->rb_root.rb_root.rb_node)) 35687906d00cSAndrea Arcangeli BUG(); 356908b52706SKonstantin Khlebnikov anon_vma_unlock_write(anon_vma); 35707906d00cSAndrea Arcangeli } 35717906d00cSAndrea Arcangeli } 35727906d00cSAndrea Arcangeli 35737906d00cSAndrea Arcangeli static void vm_unlock_mapping(struct address_space *mapping) 35747906d00cSAndrea Arcangeli { 35757906d00cSAndrea Arcangeli if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { 35767906d00cSAndrea Arcangeli /* 35777906d00cSAndrea Arcangeli * AS_MM_ALL_LOCKS can't change to 0 from under us 35787906d00cSAndrea Arcangeli * because we hold the mm_all_locks_mutex. 35797906d00cSAndrea Arcangeli */ 358083cde9e8SDavidlohr Bueso i_mmap_unlock_write(mapping); 35817906d00cSAndrea Arcangeli if (!test_and_clear_bit(AS_MM_ALL_LOCKS, 35827906d00cSAndrea Arcangeli &mapping->flags)) 35837906d00cSAndrea Arcangeli BUG(); 35847906d00cSAndrea Arcangeli } 35857906d00cSAndrea Arcangeli } 35867906d00cSAndrea Arcangeli 35877906d00cSAndrea Arcangeli /* 3588c1e8d7c6SMichel Lespinasse * The mmap_lock cannot be released by the caller until 35897906d00cSAndrea Arcangeli * mm_drop_all_locks() returns. 35907906d00cSAndrea Arcangeli */ 35917906d00cSAndrea Arcangeli void mm_drop_all_locks(struct mm_struct *mm) 35927906d00cSAndrea Arcangeli { 35937906d00cSAndrea Arcangeli struct vm_area_struct *vma; 35945beb4930SRik van Riel struct anon_vma_chain *avc; 3595763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 35967906d00cSAndrea Arcangeli 3597325bca1fSRolf Eike Beer mmap_assert_write_locked(mm); 35987906d00cSAndrea Arcangeli BUG_ON(!mutex_is_locked(&mm_all_locks_mutex)); 35997906d00cSAndrea Arcangeli 3600763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 36017906d00cSAndrea Arcangeli if (vma->anon_vma) 36025beb4930SRik van Riel list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 36035beb4930SRik van Riel vm_unlock_anon_vma(avc->anon_vma); 36047906d00cSAndrea Arcangeli if (vma->vm_file && vma->vm_file->f_mapping) 36057906d00cSAndrea Arcangeli vm_unlock_mapping(vma->vm_file->f_mapping); 36067906d00cSAndrea Arcangeli } 36077906d00cSAndrea Arcangeli 36087906d00cSAndrea Arcangeli mutex_unlock(&mm_all_locks_mutex); 36097906d00cSAndrea Arcangeli } 36108feae131SDavid Howells 36118feae131SDavid Howells /* 36123edf41d8Sseokhoon.yoon * initialise the percpu counter for VM 36138feae131SDavid Howells */ 36148feae131SDavid Howells void __init mmap_init(void) 36158feae131SDavid Howells { 361600a62ce9SKOSAKI Motohiro int ret; 361700a62ce9SKOSAKI Motohiro 3618908c7f19STejun Heo ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL); 361900a62ce9SKOSAKI Motohiro VM_BUG_ON(ret); 36208feae131SDavid Howells } 3621c9b1d098SAndrew Shewmaker 3622c9b1d098SAndrew Shewmaker /* 3623c9b1d098SAndrew Shewmaker * Initialise sysctl_user_reserve_kbytes. 3624c9b1d098SAndrew Shewmaker * 3625c9b1d098SAndrew Shewmaker * This is intended to prevent a user from starting a single memory hogging 3626c9b1d098SAndrew Shewmaker * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER 3627c9b1d098SAndrew Shewmaker * mode. 3628c9b1d098SAndrew Shewmaker * 3629c9b1d098SAndrew Shewmaker * The default value is min(3% of free memory, 128MB) 3630c9b1d098SAndrew Shewmaker * 128MB is enough to recover with sshd/login, bash, and top/kill. 3631c9b1d098SAndrew Shewmaker */ 36321640879aSAndrew Shewmaker static int init_user_reserve(void) 3633c9b1d098SAndrew Shewmaker { 3634c9b1d098SAndrew Shewmaker unsigned long free_kbytes; 3635c9b1d098SAndrew Shewmaker 3636c41f012aSMichal Hocko free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); 3637c9b1d098SAndrew Shewmaker 3638c9b1d098SAndrew Shewmaker sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17); 3639c9b1d098SAndrew Shewmaker return 0; 3640c9b1d098SAndrew Shewmaker } 3641a64fb3cdSPaul Gortmaker subsys_initcall(init_user_reserve); 36424eeab4f5SAndrew Shewmaker 36434eeab4f5SAndrew Shewmaker /* 36444eeab4f5SAndrew Shewmaker * Initialise sysctl_admin_reserve_kbytes. 36454eeab4f5SAndrew Shewmaker * 36464eeab4f5SAndrew Shewmaker * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin 36474eeab4f5SAndrew Shewmaker * to log in and kill a memory hogging process. 36484eeab4f5SAndrew Shewmaker * 36494eeab4f5SAndrew Shewmaker * Systems with more than 256MB will reserve 8MB, enough to recover 36504eeab4f5SAndrew Shewmaker * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will 36514eeab4f5SAndrew Shewmaker * only reserve 3% of free pages by default. 36524eeab4f5SAndrew Shewmaker */ 36531640879aSAndrew Shewmaker static int init_admin_reserve(void) 36544eeab4f5SAndrew Shewmaker { 36554eeab4f5SAndrew Shewmaker unsigned long free_kbytes; 36564eeab4f5SAndrew Shewmaker 3657c41f012aSMichal Hocko free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); 36584eeab4f5SAndrew Shewmaker 36594eeab4f5SAndrew Shewmaker sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13); 36604eeab4f5SAndrew Shewmaker return 0; 36614eeab4f5SAndrew Shewmaker } 3662a64fb3cdSPaul Gortmaker subsys_initcall(init_admin_reserve); 36631640879aSAndrew Shewmaker 36641640879aSAndrew Shewmaker /* 36651640879aSAndrew Shewmaker * Reinititalise user and admin reserves if memory is added or removed. 36661640879aSAndrew Shewmaker * 36671640879aSAndrew Shewmaker * The default user reserve max is 128MB, and the default max for the 36681640879aSAndrew Shewmaker * admin reserve is 8MB. These are usually, but not always, enough to 36691640879aSAndrew Shewmaker * enable recovery from a memory hogging process using login/sshd, a shell, 36701640879aSAndrew Shewmaker * and tools like top. It may make sense to increase or even disable the 36711640879aSAndrew Shewmaker * reserve depending on the existence of swap or variations in the recovery 36721640879aSAndrew Shewmaker * tools. So, the admin may have changed them. 36731640879aSAndrew Shewmaker * 36741640879aSAndrew Shewmaker * If memory is added and the reserves have been eliminated or increased above 36751640879aSAndrew Shewmaker * the default max, then we'll trust the admin. 36761640879aSAndrew Shewmaker * 36771640879aSAndrew Shewmaker * If memory is removed and there isn't enough free memory, then we 36781640879aSAndrew Shewmaker * need to reset the reserves. 36791640879aSAndrew Shewmaker * 36801640879aSAndrew Shewmaker * Otherwise keep the reserve set by the admin. 36811640879aSAndrew Shewmaker */ 36821640879aSAndrew Shewmaker static int reserve_mem_notifier(struct notifier_block *nb, 36831640879aSAndrew Shewmaker unsigned long action, void *data) 36841640879aSAndrew Shewmaker { 36851640879aSAndrew Shewmaker unsigned long tmp, free_kbytes; 36861640879aSAndrew Shewmaker 36871640879aSAndrew Shewmaker switch (action) { 36881640879aSAndrew Shewmaker case MEM_ONLINE: 36891640879aSAndrew Shewmaker /* Default max is 128MB. Leave alone if modified by operator. */ 36901640879aSAndrew Shewmaker tmp = sysctl_user_reserve_kbytes; 36911640879aSAndrew Shewmaker if (0 < tmp && tmp < (1UL << 17)) 36921640879aSAndrew Shewmaker init_user_reserve(); 36931640879aSAndrew Shewmaker 36941640879aSAndrew Shewmaker /* Default max is 8MB. Leave alone if modified by operator. */ 36951640879aSAndrew Shewmaker tmp = sysctl_admin_reserve_kbytes; 36961640879aSAndrew Shewmaker if (0 < tmp && tmp < (1UL << 13)) 36971640879aSAndrew Shewmaker init_admin_reserve(); 36981640879aSAndrew Shewmaker 36991640879aSAndrew Shewmaker break; 37001640879aSAndrew Shewmaker case MEM_OFFLINE: 3701c41f012aSMichal Hocko free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); 37021640879aSAndrew Shewmaker 37031640879aSAndrew Shewmaker if (sysctl_user_reserve_kbytes > free_kbytes) { 37041640879aSAndrew Shewmaker init_user_reserve(); 37051640879aSAndrew Shewmaker pr_info("vm.user_reserve_kbytes reset to %lu\n", 37061640879aSAndrew Shewmaker sysctl_user_reserve_kbytes); 37071640879aSAndrew Shewmaker } 37081640879aSAndrew Shewmaker 37091640879aSAndrew Shewmaker if (sysctl_admin_reserve_kbytes > free_kbytes) { 37101640879aSAndrew Shewmaker init_admin_reserve(); 37111640879aSAndrew Shewmaker pr_info("vm.admin_reserve_kbytes reset to %lu\n", 37121640879aSAndrew Shewmaker sysctl_admin_reserve_kbytes); 37131640879aSAndrew Shewmaker } 37141640879aSAndrew Shewmaker break; 37151640879aSAndrew Shewmaker default: 37161640879aSAndrew Shewmaker break; 37171640879aSAndrew Shewmaker } 37181640879aSAndrew Shewmaker return NOTIFY_OK; 37191640879aSAndrew Shewmaker } 37201640879aSAndrew Shewmaker 37211640879aSAndrew Shewmaker static int __meminit init_reserve_notifier(void) 37221640879aSAndrew Shewmaker { 37231eeaa4fdSLiu Shixin if (hotplug_memory_notifier(reserve_mem_notifier, DEFAULT_CALLBACK_PRI)) 3724b1de0d13SMitchel Humpherys pr_err("Failed registering memory add/remove notifier for admin reserve\n"); 37251640879aSAndrew Shewmaker 37261640879aSAndrew Shewmaker return 0; 37271640879aSAndrew Shewmaker } 3728a64fb3cdSPaul Gortmaker subsys_initcall(init_reserve_notifier); 3729