1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * This file contains the routines setting up the linux page tables. 4 * -- paulus 5 * 6 * Derived from arch/ppc/mm/init.c: 7 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) 8 * 9 * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au) 10 * and Cort Dougan (PReP) (cort@cs.nmt.edu) 11 * Copyright (C) 1996 Paul Mackerras 12 * 13 * Derived from "arch/i386/mm/init.c" 14 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds 15 */ 16 17 #include <linux/kernel.h> 18 #include <linux/module.h> 19 #include <linux/types.h> 20 #include <linux/mm.h> 21 #include <linux/vmalloc.h> 22 #include <linux/init.h> 23 #include <linux/highmem.h> 24 #include <linux/memblock.h> 25 #include <linux/slab.h> 26 27 #include <asm/pgtable.h> 28 #include <asm/pgalloc.h> 29 #include <asm/fixmap.h> 30 #include <asm/io.h> 31 #include <asm/setup.h> 32 #include <asm/sections.h> 33 34 #include <mm/mmu_decl.h> 35 36 unsigned long ioremap_bot; 37 EXPORT_SYMBOL(ioremap_bot); /* aka VMALLOC_END */ 38 39 extern char etext[], _stext[], _sinittext[], _einittext[]; 40 41 void __iomem * 42 ioremap(phys_addr_t addr, unsigned long size) 43 { 44 pgprot_t prot = pgprot_noncached(PAGE_KERNEL); 45 46 return __ioremap_caller(addr, size, prot, __builtin_return_address(0)); 47 } 48 EXPORT_SYMBOL(ioremap); 49 50 void __iomem * 51 ioremap_wc(phys_addr_t addr, unsigned long size) 52 { 53 pgprot_t prot = pgprot_noncached_wc(PAGE_KERNEL); 54 55 return __ioremap_caller(addr, size, prot, __builtin_return_address(0)); 56 } 57 EXPORT_SYMBOL(ioremap_wc); 58 59 void __iomem * 60 ioremap_wt(phys_addr_t addr, unsigned long size) 61 { 62 pgprot_t prot = pgprot_cached_wthru(PAGE_KERNEL); 63 64 return __ioremap_caller(addr, size, prot, __builtin_return_address(0)); 65 } 66 EXPORT_SYMBOL(ioremap_wt); 67 68 void __iomem * 69 ioremap_coherent(phys_addr_t addr, unsigned long size) 70 { 71 pgprot_t prot = pgprot_cached(PAGE_KERNEL); 72 73 return __ioremap_caller(addr, size, prot, __builtin_return_address(0)); 74 } 75 EXPORT_SYMBOL(ioremap_coherent); 76 77 void __iomem * 78 ioremap_prot(phys_addr_t addr, unsigned long size, unsigned long flags) 79 { 80 pte_t pte = __pte(flags); 81 82 /* writeable implies dirty for kernel addresses */ 83 if (pte_write(pte)) 84 pte = pte_mkdirty(pte); 85 86 /* we don't want to let _PAGE_USER and _PAGE_EXEC leak out */ 87 pte = pte_exprotect(pte); 88 pte = pte_mkprivileged(pte); 89 90 return __ioremap_caller(addr, size, pte_pgprot(pte), __builtin_return_address(0)); 91 } 92 EXPORT_SYMBOL(ioremap_prot); 93 94 void __iomem * 95 __ioremap(phys_addr_t addr, unsigned long size, unsigned long flags) 96 { 97 return __ioremap_caller(addr, size, __pgprot(flags), __builtin_return_address(0)); 98 } 99 100 void __iomem * 101 __ioremap_caller(phys_addr_t addr, unsigned long size, pgprot_t prot, void *caller) 102 { 103 unsigned long v, i; 104 phys_addr_t p; 105 int err; 106 107 /* 108 * Choose an address to map it to. 109 * Once the vmalloc system is running, we use it. 110 * Before then, we use space going down from IOREMAP_TOP 111 * (ioremap_bot records where we're up to). 112 */ 113 p = addr & PAGE_MASK; 114 size = PAGE_ALIGN(addr + size) - p; 115 116 /* 117 * If the address lies within the first 16 MB, assume it's in ISA 118 * memory space 119 */ 120 if (p < 16*1024*1024) 121 p += _ISA_MEM_BASE; 122 123 #ifndef CONFIG_CRASH_DUMP 124 /* 125 * Don't allow anybody to remap normal RAM that we're using. 126 * mem_init() sets high_memory so only do the check after that. 127 */ 128 if (slab_is_available() && p <= virt_to_phys(high_memory - 1) && 129 page_is_ram(__phys_to_pfn(p))) { 130 printk("__ioremap(): phys addr 0x%llx is RAM lr %ps\n", 131 (unsigned long long)p, __builtin_return_address(0)); 132 return NULL; 133 } 134 #endif 135 136 if (size == 0) 137 return NULL; 138 139 /* 140 * Is it already mapped? Perhaps overlapped by a previous 141 * mapping. 142 */ 143 v = p_block_mapped(p); 144 if (v) 145 goto out; 146 147 if (slab_is_available()) { 148 struct vm_struct *area; 149 area = get_vm_area_caller(size, VM_IOREMAP, caller); 150 if (area == 0) 151 return NULL; 152 area->phys_addr = p; 153 v = (unsigned long) area->addr; 154 } else { 155 v = (ioremap_bot -= size); 156 } 157 158 /* 159 * Should check if it is a candidate for a BAT mapping 160 */ 161 162 err = 0; 163 for (i = 0; i < size && err == 0; i += PAGE_SIZE) 164 err = map_kernel_page(v + i, p + i, prot); 165 if (err) { 166 if (slab_is_available()) 167 vunmap((void *)v); 168 return NULL; 169 } 170 171 out: 172 return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK)); 173 } 174 EXPORT_SYMBOL(__ioremap); 175 176 void iounmap(volatile void __iomem *addr) 177 { 178 /* 179 * If mapped by BATs then there is nothing to do. 180 * Calling vfree() generates a benign warning. 181 */ 182 if (v_block_mapped((unsigned long)addr)) 183 return; 184 185 if (addr > high_memory && (unsigned long) addr < ioremap_bot) 186 vunmap((void *) (PAGE_MASK & (unsigned long)addr)); 187 } 188 EXPORT_SYMBOL(iounmap); 189 190 static void __init *early_alloc_pgtable(unsigned long size) 191 { 192 void *ptr = memblock_alloc(size, size); 193 194 if (!ptr) 195 panic("%s: Failed to allocate %lu bytes align=0x%lx\n", 196 __func__, size, size); 197 198 return ptr; 199 } 200 201 static pte_t __init *early_pte_alloc_kernel(pmd_t *pmdp, unsigned long va) 202 { 203 if (pmd_none(*pmdp)) { 204 pte_t *ptep = early_alloc_pgtable(PTE_FRAG_SIZE); 205 206 pmd_populate_kernel(&init_mm, pmdp, ptep); 207 } 208 return pte_offset_kernel(pmdp, va); 209 } 210 211 212 int __ref map_kernel_page(unsigned long va, phys_addr_t pa, pgprot_t prot) 213 { 214 pmd_t *pd; 215 pte_t *pg; 216 int err = -ENOMEM; 217 218 /* Use upper 10 bits of VA to index the first level map */ 219 pd = pmd_offset(pud_offset(pgd_offset_k(va), va), va); 220 /* Use middle 10 bits of VA to index the second-level map */ 221 if (likely(slab_is_available())) 222 pg = pte_alloc_kernel(pd, va); 223 else 224 pg = early_pte_alloc_kernel(pd, va); 225 if (pg != 0) { 226 err = 0; 227 /* The PTE should never be already set nor present in the 228 * hash table 229 */ 230 BUG_ON((pte_present(*pg) | pte_hashpte(*pg)) && pgprot_val(prot)); 231 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, prot)); 232 } 233 smp_wmb(); 234 return err; 235 } 236 237 /* 238 * Map in a chunk of physical memory starting at start. 239 */ 240 static void __init __mapin_ram_chunk(unsigned long offset, unsigned long top) 241 { 242 unsigned long v, s; 243 phys_addr_t p; 244 int ktext; 245 246 s = offset; 247 v = PAGE_OFFSET + s; 248 p = memstart_addr + s; 249 for (; s < top; s += PAGE_SIZE) { 250 ktext = ((char *)v >= _stext && (char *)v < etext) || 251 ((char *)v >= _sinittext && (char *)v < _einittext); 252 map_kernel_page(v, p, ktext ? PAGE_KERNEL_TEXT : PAGE_KERNEL); 253 #ifdef CONFIG_PPC_BOOK3S_32 254 if (ktext) 255 hash_preload(&init_mm, v, false, 0x300); 256 #endif 257 v += PAGE_SIZE; 258 p += PAGE_SIZE; 259 } 260 } 261 262 void __init mapin_ram(void) 263 { 264 struct memblock_region *reg; 265 266 for_each_memblock(memory, reg) { 267 phys_addr_t base = reg->base; 268 phys_addr_t top = min(base + reg->size, total_lowmem); 269 270 if (base >= top) 271 continue; 272 base = mmu_mapin_ram(base, top); 273 if (IS_ENABLED(CONFIG_BDI_SWITCH)) 274 __mapin_ram_chunk(reg->base, top); 275 else 276 __mapin_ram_chunk(base, top); 277 } 278 } 279 280 /* Scan the real Linux page tables and return a PTE pointer for 281 * a virtual address in a context. 282 * Returns true (1) if PTE was found, zero otherwise. The pointer to 283 * the PTE pointer is unmodified if PTE is not found. 284 */ 285 static int 286 get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp) 287 { 288 pgd_t *pgd; 289 pud_t *pud; 290 pmd_t *pmd; 291 pte_t *pte; 292 int retval = 0; 293 294 pgd = pgd_offset(mm, addr & PAGE_MASK); 295 if (pgd) { 296 pud = pud_offset(pgd, addr & PAGE_MASK); 297 if (pud && pud_present(*pud)) { 298 pmd = pmd_offset(pud, addr & PAGE_MASK); 299 if (pmd_present(*pmd)) { 300 pte = pte_offset_map(pmd, addr & PAGE_MASK); 301 if (pte) { 302 retval = 1; 303 *ptep = pte; 304 if (pmdp) 305 *pmdp = pmd; 306 /* XXX caller needs to do pte_unmap, yuck */ 307 } 308 } 309 } 310 } 311 return(retval); 312 } 313 314 static int __change_page_attr_noflush(struct page *page, pgprot_t prot) 315 { 316 pte_t *kpte; 317 pmd_t *kpmd; 318 unsigned long address; 319 320 BUG_ON(PageHighMem(page)); 321 address = (unsigned long)page_address(page); 322 323 if (v_block_mapped(address)) 324 return 0; 325 if (!get_pteptr(&init_mm, address, &kpte, &kpmd)) 326 return -EINVAL; 327 __set_pte_at(&init_mm, address, kpte, mk_pte(page, prot), 0); 328 pte_unmap(kpte); 329 330 return 0; 331 } 332 333 /* 334 * Change the page attributes of an page in the linear mapping. 335 * 336 * THIS DOES NOTHING WITH BAT MAPPINGS, DEBUG USE ONLY 337 */ 338 static int change_page_attr(struct page *page, int numpages, pgprot_t prot) 339 { 340 int i, err = 0; 341 unsigned long flags; 342 struct page *start = page; 343 344 local_irq_save(flags); 345 for (i = 0; i < numpages; i++, page++) { 346 err = __change_page_attr_noflush(page, prot); 347 if (err) 348 break; 349 } 350 wmb(); 351 local_irq_restore(flags); 352 flush_tlb_kernel_range((unsigned long)page_address(start), 353 (unsigned long)page_address(page)); 354 return err; 355 } 356 357 void mark_initmem_nx(void) 358 { 359 struct page *page = virt_to_page(_sinittext); 360 unsigned long numpages = PFN_UP((unsigned long)_einittext) - 361 PFN_DOWN((unsigned long)_sinittext); 362 363 if (v_block_mapped((unsigned long)_stext) + 1) 364 mmu_mark_initmem_nx(); 365 else 366 change_page_attr(page, numpages, PAGE_KERNEL); 367 } 368 369 #ifdef CONFIG_STRICT_KERNEL_RWX 370 void mark_rodata_ro(void) 371 { 372 struct page *page; 373 unsigned long numpages; 374 375 if (v_block_mapped((unsigned long)_sinittext)) { 376 mmu_mark_rodata_ro(); 377 return; 378 } 379 380 page = virt_to_page(_stext); 381 numpages = PFN_UP((unsigned long)_etext) - 382 PFN_DOWN((unsigned long)_stext); 383 384 change_page_attr(page, numpages, PAGE_KERNEL_ROX); 385 /* 386 * mark .rodata as read only. Use __init_begin rather than __end_rodata 387 * to cover NOTES and EXCEPTION_TABLE. 388 */ 389 page = virt_to_page(__start_rodata); 390 numpages = PFN_UP((unsigned long)__init_begin) - 391 PFN_DOWN((unsigned long)__start_rodata); 392 393 change_page_attr(page, numpages, PAGE_KERNEL_RO); 394 395 // mark_initmem_nx() should have already run by now 396 ptdump_check_wx(); 397 } 398 #endif 399 400 #ifdef CONFIG_DEBUG_PAGEALLOC 401 void __kernel_map_pages(struct page *page, int numpages, int enable) 402 { 403 if (PageHighMem(page)) 404 return; 405 406 change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0)); 407 } 408 #endif /* CONFIG_DEBUG_PAGEALLOC */ 409