arch/arm/mm/flush.c

   1 /*
   2  *  linux/arch/arm/mm/flush.c
   3  *
   4  *  Copyright (C) 1995-2002 Russell King
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10 #include <linux/module.h>
  11 #include <linux/mm.h>
  12 #include <linux/pagemap.h>
  13 #include <linux/highmem.h>
  14
  15 #include <asm/cacheflush.h>
  16 #include <asm/cachetype.h>
  17 #include <asm/highmem.h>
  18 #include <asm/smp_plat.h>
  19 #include <asm/tlbflush.h>
  20 #include <linux/hugetlb.h>
  21
  22 #include "mm.h"
  23
  24 #ifdef CONFIG_CPU_CACHE_VIPT
  25
  26 static void flush_pfn_alias(unsigned long pfn, unsigned long vaddr)
  27 {
  28         unsigned long to = FLUSH_ALIAS_START + (CACHE_COLOUR(vaddr) << PAGE_SHIFT);
  29         const int zero = 0;
  30
  31         set_top_pte(to, pfn_pte(pfn, PAGE_KERNEL));
  32
  33         asm(    "mcrr   p15, 0, %1, %0, c14\n"
  34         "       mcr     p15, 0, %2, c7, c10, 4"
  35             :
  36             : "r" (to), "r" (to + PAGE_SIZE - L1_CACHE_BYTES), "r" (zero)
  37             : "cc");
  38 }
  39
  40 static void flush_icache_alias(unsigned long pfn, unsigned long vaddr, unsigned long len)
  41 {
  42         unsigned long va = FLUSH_ALIAS_START + (CACHE_COLOUR(vaddr) << PAGE_SHIFT);
  43         unsigned long offset = vaddr & (PAGE_SIZE - 1);
  44         unsigned long to;
  45
  46         set_top_pte(va, pfn_pte(pfn, PAGE_KERNEL));
  47         to = va + offset;
  48         flush_icache_range(to, to + len);
  49 }
  50
  51 void flush_cache_mm(struct mm_struct *mm)
  52 {
  53         if (cache_is_vivt()) {
  54                 vivt_flush_cache_mm(mm);
  55                 return;
  56         }
  57
  58         if (cache_is_vipt_aliasing()) {
  59                 asm(    "mcr    p15, 0, %0, c7, c14, 0\n"
  60                 "       mcr     p15, 0, %0, c7, c10, 4"
  61                     :
  62                     : "r" (0)
  63                     : "cc");
  64         }
  65 }
  66
  67 void flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned long end)
  68 {
  69         if (cache_is_vivt()) {
  70                 vivt_flush_cache_range(vma, start, end);
  71                 return;
  72         }
  73
  74         if (cache_is_vipt_aliasing()) {
  75                 asm(    "mcr    p15, 0, %0, c7, c14, 0\n"
  76                 "       mcr     p15, 0, %0, c7, c10, 4"
  77                     :
  78                     : "r" (0)
  79                     : "cc");
  80         }
  81
  82         if (vma->vm_flags & VM_EXEC)
  83                 __flush_icache_all();
  84 }
  85
  86 void flush_cache_page(struct vm_area_struct *vma, unsigned long user_addr, unsigned long pfn)
  87 {
  88         if (cache_is_vivt()) {
  89                 vivt_flush_cache_page(vma, user_addr, pfn);
  90                 return;
  91         }
  92
  93         if (cache_is_vipt_aliasing()) {
  94                 flush_pfn_alias(pfn, user_addr);
  95                 __flush_icache_all();
  96         }
  97
  98         if (vma->vm_flags & VM_EXEC && icache_is_vivt_asid_tagged())
  99                 __flush_icache_all();
 100 }
 101
 102 #else
 103 #define flush_pfn_alias(pfn,vaddr)              do { } while (0)
 104 #define flush_icache_alias(pfn,vaddr,len)       do { } while (0)
 105 #endif
 106
 107 #define FLAG_PA_IS_EXEC 1
 108 #define FLAG_PA_CORE_IN_MM 2
 109
 110 static void flush_ptrace_access_other(void *args)
 111 {
 112         __flush_icache_all();
 113 }
 114
 115 static inline
 116 void __flush_ptrace_access(struct page *page, unsigned long uaddr, void *kaddr,
 117                            unsigned long len, unsigned int flags)
 118 {
 119         if (cache_is_vivt()) {
 120                 if (flags & FLAG_PA_CORE_IN_MM) {
 121                         unsigned long addr = (unsigned long)kaddr;
 122                         __cpuc_coherent_kern_range(addr, addr + len);
 123                 }
 124                 return;
 125         }
 126
 127         if (cache_is_vipt_aliasing()) {
 128                 flush_pfn_alias(page_to_pfn(page), uaddr);
 129                 __flush_icache_all();
 130                 return;
 131         }
 132
 133         /* VIPT non-aliasing D-cache */
 134         if (flags & FLAG_PA_IS_EXEC) {
 135                 unsigned long addr = (unsigned long)kaddr;
 136                 if (icache_is_vipt_aliasing())
 137                         flush_icache_alias(page_to_pfn(page), uaddr, len);
 138                 else
 139                         __cpuc_coherent_kern_range(addr, addr + len);
 140                 if (cache_ops_need_broadcast())
 141                         smp_call_function(flush_ptrace_access_other,
 142                                           NULL, 1);
 143         }
 144 }
 145
 146 static
 147 void flush_ptrace_access(struct vm_area_struct *vma, struct page *page,
 148                          unsigned long uaddr, void *kaddr, unsigned long len)
 149 {
 150         unsigned int flags = 0;
 151         if (cpumask_test_cpu(smp_processor_id(), mm_cpumask(vma->vm_mm)))
 152                 flags |= FLAG_PA_CORE_IN_MM;
 153         if (vma->vm_flags & VM_EXEC)
 154                 flags |= FLAG_PA_IS_EXEC;
 155         __flush_ptrace_access(page, uaddr, kaddr, len, flags);
 156 }
 157
 158 void flush_uprobe_xol_access(struct page *page, unsigned long uaddr,
 159                              void *kaddr, unsigned long len)
 160 {
 161         unsigned int flags = FLAG_PA_CORE_IN_MM|FLAG_PA_IS_EXEC;
 162
 163         __flush_ptrace_access(page, uaddr, kaddr, len, flags);
 164 }
 165
 166 /*
 167  * Copy user data from/to a page which is mapped into a different
 168  * processes address space.  Really, we want to allow our "user
 169  * space" model to handle this.
 170  *
 171  * Note that this code needs to run on the current CPU.
 172  */
 173 void copy_to_user_page(struct vm_area_struct *vma, struct page *page,
 174                        unsigned long uaddr, void *dst, const void *src,
 175                        unsigned long len)
 176 {
 177 #ifdef CONFIG_SMP
 178         preempt_disable();
 179 #endif
 180         memcpy(dst, src, len);
 181         flush_ptrace_access(vma, page, uaddr, dst, len);
 182 #ifdef CONFIG_SMP
 183         preempt_enable();
 184 #endif
 185 }
 186
 187 void __flush_dcache_page(struct address_space *mapping, struct page *page)
 188 {
 189         /*
 190          * Writeback any data associated with the kernel mapping of this
 191          * page.  This ensures that data in the physical page is mutually
 192          * coherent with the kernels mapping.
 193          */
 194         if (!PageHighMem(page)) {
 195                 size_t page_size = PAGE_SIZE << compound_order(page);
 196                 __cpuc_flush_dcache_area(page_address(page), page_size);
 197         } else {
 198                 unsigned long i;
 199                 if (cache_is_vipt_nonaliasing()) {
 200                         for (i = 0; i < (1 << compound_order(page)); i++) {
 201                                 void *addr = kmap_atomic(page + i);
 202                                 __cpuc_flush_dcache_area(addr, PAGE_SIZE);
 203                                 kunmap_atomic(addr);
 204                         }
 205                 } else {
 206                         for (i = 0; i < (1 << compound_order(page)); i++) {
 207                                 void *addr = kmap_high_get(page + i);
 208                                 if (addr) {
 209                                         __cpuc_flush_dcache_area(addr, PAGE_SIZE);
 210                                         kunmap_high(page + i);
 211                                 }
 212                         }
 213                 }
 214         }
 215
 216         /*
 217          * If this is a page cache page, and we have an aliasing VIPT cache,
 218          * we only need to do one flush - which would be at the relevant
 219          * userspace colour, which is congruent with page->index.
 220          */
 221         if (mapping && cache_is_vipt_aliasing())
 222                 flush_pfn_alias(page_to_pfn(page),
 223                                 page->index << PAGE_CACHE_SHIFT);
 224 }
 225
 226 static void __flush_dcache_aliases(struct address_space *mapping, struct page *page)
 227 {
 228         struct mm_struct *mm = current->active_mm;
 229         struct vm_area_struct *mpnt;
 230         pgoff_t pgoff;
 231
 232         /*
 233          * There are possible user space mappings of this page:
 234          * - VIVT cache: we need to also write back and invalidate all user
 235          *   data in the current VM view associated with this page.
 236          * - aliasing VIPT: we only need to find one mapping of this page.
 237          */
 238         pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
 239
 240         flush_dcache_mmap_lock(mapping);
 241         vma_interval_tree_foreach(mpnt, &mapping->i_mmap, pgoff, pgoff) {
 242                 unsigned long offset;
 243
 244                 /*
 245                  * If this VMA is not in our MM, we can ignore it.
 246                  */
 247                 if (mpnt->vm_mm != mm)
 248                         continue;
 249                 if (!(mpnt->vm_flags & VM_MAYSHARE))
 250                         continue;
 251                 offset = (pgoff - mpnt->vm_pgoff) << PAGE_SHIFT;
 252                 flush_cache_page(mpnt, mpnt->vm_start + offset, page_to_pfn(page));
 253         }
 254         flush_dcache_mmap_unlock(mapping);
 255 }
 256
 257 #if __LINUX_ARM_ARCH__ >= 6
 258 void __sync_icache_dcache(pte_t pteval)
 259 {
 260         unsigned long pfn;
 261         struct page *page;
 262         struct address_space *mapping;
 263
 264         if (cache_is_vipt_nonaliasing() && !pte_exec(pteval))
 265                 /* only flush non-aliasing VIPT caches for exec mappings */
 266                 return;
 267         pfn = pte_pfn(pteval);
 268         if (!pfn_valid(pfn))
 269                 return;
 270
 271         page = pfn_to_page(pfn);
 272         if (cache_is_vipt_aliasing())
 273                 mapping = page_mapping(page);
 274         else
 275                 mapping = NULL;
 276
 277         if (!test_and_set_bit(PG_dcache_clean, &page->flags))
 278                 __flush_dcache_page(mapping, page);
 279
 280         if (pte_exec(pteval))
 281                 __flush_icache_all();
 282 }
 283 #endif
 284
 285 /*
 286  * Ensure cache coherency between kernel mapping and userspace mapping
 287  * of this page.
 288  *
 289  * We have three cases to consider:
 290  *  - VIPT non-aliasing cache: fully coherent so nothing required.
 291  *  - VIVT: fully aliasing, so we need to handle every alias in our
 292  *          current VM view.
 293  *  - VIPT aliasing: need to handle one alias in our current VM view.
 294  *
 295  * If we need to handle aliasing:
 296  *  If the page only exists in the page cache and there are no user
 297  *  space mappings, we can be lazy and remember that we may have dirty
 298  *  kernel cache lines for later.  Otherwise, we assume we have
 299  *  aliasing mappings.
 300  *
 301  * Note that we disable the lazy flush for SMP configurations where
 302  * the cache maintenance operations are not automatically broadcasted.
 303  */
 304 void flush_dcache_page(struct page *page)
 305 {
 306         struct address_space *mapping;
 307
 308         /*
 309          * The zero page is never written to, so never has any dirty
 310          * cache lines, and therefore never needs to be flushed.
 311          */
 312         if (page == ZERO_PAGE(0))
 313                 return;
 314
 315         mapping = page_mapping(page);
 316
 317         if (!cache_ops_need_broadcast() &&
 318             mapping && !page_mapped(page))
 319                 clear_bit(PG_dcache_clean, &page->flags);
 320         else {
 321                 __flush_dcache_page(mapping, page);
 322                 if (mapping && cache_is_vivt())
 323                         __flush_dcache_aliases(mapping, page);
 324                 else if (mapping)
 325                         __flush_icache_all();
 326                 set_bit(PG_dcache_clean, &page->flags);
 327         }
 328 }
 329 EXPORT_SYMBOL(flush_dcache_page);
 330
 331 /*
 332  * Ensure cache coherency for the kernel mapping of this page. We can
 333  * assume that the page is pinned via kmap.
 334  *
 335  * If the page only exists in the page cache and there are no user
 336  * space mappings, this is a no-op since the page was already marked
 337  * dirty at creation.  Otherwise, we need to flush the dirty kernel
 338  * cache lines directly.
 339  */
 340 void flush_kernel_dcache_page(struct page *page)
 341 {
 342         if (cache_is_vivt() || cache_is_vipt_aliasing()) {
 343                 struct address_space *mapping;
 344
 345                 mapping = page_mapping(page);
 346
 347                 if (!mapping || mapping_mapped(mapping)) {
 348                         void *addr;
 349
 350                         addr = page_address(page);
 351                         /*
 352                          * kmap_atomic() doesn't set the page virtual
 353                          * address for highmem pages, and
 354                          * kunmap_atomic() takes care of cache
 355                          * flushing already.
 356                          */
 357                         if (!IS_ENABLED(CONFIG_HIGHMEM) || addr)
 358                                 __cpuc_flush_dcache_area(addr, PAGE_SIZE);
 359                 }
 360         }
 361 }
 362 EXPORT_SYMBOL(flush_kernel_dcache_page);
 363
 364 /*
 365  * Flush an anonymous page so that users of get_user_pages()
 366  * can safely access the data.  The expected sequence is:
 367  *
 368  *  get_user_pages()
 369  *    -> flush_anon_page
 370  *  memcpy() to/from page
 371  *  if written to page, flush_dcache_page()
 372  */
 373 void __flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
 374 {
 375         unsigned long pfn;
 376
 377         /* VIPT non-aliasing caches need do nothing */
 378         if (cache_is_vipt_nonaliasing())
 379                 return;
 380
 381         /*
 382          * Write back and invalidate userspace mapping.
 383          */
 384         pfn = page_to_pfn(page);
 385         if (cache_is_vivt()) {
 386                 flush_cache_page(vma, vmaddr, pfn);
 387         } else {
 388                 /*
 389                  * For aliasing VIPT, we can flush an alias of the
 390                  * userspace address only.
 391                  */
 392                 flush_pfn_alias(pfn, vmaddr);
 393                 __flush_icache_all();
 394         }
 395
 396         /*
 397          * Invalidate kernel mapping.  No data should be contained
 398          * in this mapping of the page.  FIXME: this is overkill
 399          * since we actually ask for a write-back and invalidate.
 400          */
 401         __cpuc_flush_dcache_area(page_address(page), PAGE_SIZE);
 402 }
 403
 404 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 405 #ifdef CONFIG_HAVE_RCU_TABLE_FREE
 406 void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
 407                           pmd_t *pmdp)
 408 {
 409         pmd_t pmd = pmd_mksplitting(*pmdp);
 410         VM_BUG_ON(address & ~PMD_MASK);
 411         set_pmd_at(vma->vm_mm, address, pmdp, pmd);
 412
 413         /* dummy IPI to serialise against fast_gup */
 414         kick_all_cpus_sync();
 415 }
 416 #endif /* CONFIG_HAVE_RCU_TABLE_FREE */
 417 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */