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/system.h>
  20 #include <asm/tlbflush.h>
  21
  22 #include "mm.h"
  23
  24 #ifdef CONFIG_CPU_CACHE_VIPT
  25
  26 #define ALIAS_FLUSH_START       0xffff4000
  27
  28 static void flush_pfn_alias(unsigned long pfn, unsigned long vaddr)
  29 {
  30         unsigned long to = ALIAS_FLUSH_START + (CACHE_COLOUR(vaddr) << PAGE_SHIFT);
  31         const int zero = 0;
  32
  33         set_pte_ext(TOP_PTE(to), pfn_pte(pfn, PAGE_KERNEL), 0);
  34         flush_tlb_kernel_page(to);
  35
  36         asm(    "mcrr   p15, 0, %1, %0, c14\n"
  37         "       mcr     p15, 0, %2, c7, c10, 4"
  38             :
  39             : "r" (to), "r" (to + PAGE_SIZE - L1_CACHE_BYTES), "r" (zero)
  40             : "cc");
  41 }
  42
  43 static void flush_icache_alias(unsigned long pfn, unsigned long vaddr, unsigned long len)
  44 {
  45         unsigned long colour = CACHE_COLOUR(vaddr);
  46         unsigned long offset = vaddr & (PAGE_SIZE - 1);
  47         unsigned long to;
  48
  49         set_pte_ext(TOP_PTE(ALIAS_FLUSH_START) + colour, pfn_pte(pfn, PAGE_KERNEL), 0);
  50         to = ALIAS_FLUSH_START + (colour << PAGE_SHIFT) + offset;
  51         flush_tlb_kernel_page(to);
  52         flush_icache_range(to, to + len);
  53 }
  54
  55 void flush_cache_mm(struct mm_struct *mm)
  56 {
  57         if (cache_is_vivt()) {
  58                 vivt_flush_cache_mm(mm);
  59                 return;
  60         }
  61
  62         if (cache_is_vipt_aliasing()) {
  63                 asm(    "mcr    p15, 0, %0, c7, c14, 0\n"
  64                 "       mcr     p15, 0, %0, c7, c10, 4"
  65                     :
  66                     : "r" (0)
  67                     : "cc");
  68         }
  69 }
  70
  71 void flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned long end)
  72 {
  73         if (cache_is_vivt()) {
  74                 vivt_flush_cache_range(vma, start, end);
  75                 return;
  76         }
  77
  78         if (cache_is_vipt_aliasing()) {
  79                 asm(    "mcr    p15, 0, %0, c7, c14, 0\n"
  80                 "       mcr     p15, 0, %0, c7, c10, 4"
  81                     :
  82                     : "r" (0)
  83                     : "cc");
  84         }
  85
  86         if (vma->vm_flags & VM_EXEC)
  87                 __flush_icache_all();
  88 }
  89
  90 void flush_cache_page(struct vm_area_struct *vma, unsigned long user_addr, unsigned long pfn)
  91 {
  92         if (cache_is_vivt()) {
  93                 vivt_flush_cache_page(vma, user_addr, pfn);
  94                 return;
  95         }
  96
  97         if (cache_is_vipt_aliasing()) {
  98                 flush_pfn_alias(pfn, user_addr);
  99                 __flush_icache_all();
 100         }
 101
 102         if (vma->vm_flags & VM_EXEC && icache_is_vivt_asid_tagged())
 103                 __flush_icache_all();
 104 }
 105
 106 #else
 107 #define flush_pfn_alias(pfn,vaddr)              do { } while (0)
 108 #define flush_icache_alias(pfn,vaddr,len)       do { } while (0)
 109 #endif
 110
 111 static void flush_ptrace_access_other(void *args)
 112 {
 113         __flush_icache_all();
 114 }
 115
 116 static
 117 void flush_ptrace_access(struct vm_area_struct *vma, struct page *page,
 118                          unsigned long uaddr, void *kaddr, unsigned long len)
 119 {
 120         if (cache_is_vivt()) {
 121                 if (cpumask_test_cpu(smp_processor_id(), mm_cpumask(vma->vm_mm))) {
 122                         unsigned long addr = (unsigned long)kaddr;
 123                         __cpuc_coherent_kern_range(addr, addr + len);
 124                 }
 125                 return;
 126         }
 127
 128         if (cache_is_vipt_aliasing()) {
 129                 flush_pfn_alias(page_to_pfn(page), uaddr);
 130                 __flush_icache_all();
 131                 return;
 132         }
 133
 134         /* VIPT non-aliasing D-cache */
 135         if (vma->vm_flags & VM_EXEC) {
 136                 unsigned long addr = (unsigned long)kaddr;
 137                 if (icache_is_vipt_aliasing())
 138                         flush_icache_alias(page_to_pfn(page), uaddr, len);
 139                 else
 140                         __cpuc_coherent_kern_range(addr, addr + len);
 141                 if (cache_ops_need_broadcast())
 142                         smp_call_function(flush_ptrace_access_other,
 143                                           NULL, 1);
 144         }
 145 }
 146
 147 /*
 148  * Copy user data from/to a page which is mapped into a different
 149  * processes address space.  Really, we want to allow our "user
 150  * space" model to handle this.
 151  *
 152  * Note that this code needs to run on the current CPU.
 153  */
 154 void copy_to_user_page(struct vm_area_struct *vma, struct page *page,
 155                        unsigned long uaddr, void *dst, const void *src,
 156                        unsigned long len)
 157 {
 158 #ifdef CONFIG_SMP
 159         preempt_disable();
 160 #endif
 161         memcpy(dst, src, len);
 162         flush_ptrace_access(vma, page, uaddr, dst, len);
 163 #ifdef CONFIG_SMP
 164         preempt_enable();
 165 #endif
 166 }
 167
 168 void __flush_dcache_page(struct address_space *mapping, struct page *page)
 169 {
 170         /*
 171          * Writeback any data associated with the kernel mapping of this
 172          * page.  This ensures that data in the physical page is mutually
 173          * coherent with the kernels mapping.
 174          */
 175         if (!PageHighMem(page)) {
 176                 __cpuc_flush_dcache_area(page_address(page), PAGE_SIZE);
 177         } else {
 178                 void *addr = kmap_high_get(page);
 179                 if (addr) {
 180                         __cpuc_flush_dcache_area(addr, PAGE_SIZE);
 181                         kunmap_high(page);
 182                 } else if (cache_is_vipt()) {
 183                         /* unmapped pages might still be cached */
 184                         addr = kmap_atomic(page);
 185                         __cpuc_flush_dcache_area(addr, PAGE_SIZE);
 186                         kunmap_atomic(addr);
 187                 }
 188         }
 189
 190         /*
 191          * If this is a page cache page, and we have an aliasing VIPT cache,
 192          * we only need to do one flush - which would be at the relevant
 193          * userspace colour, which is congruent with page->index.
 194          */
 195         if (mapping && cache_is_vipt_aliasing())
 196                 flush_pfn_alias(page_to_pfn(page),
 197                                 page->index << PAGE_CACHE_SHIFT);
 198 }
 199
 200 static void __flush_dcache_aliases(struct address_space *mapping, struct page *page)
 201 {
 202         struct mm_struct *mm = current->active_mm;
 203         struct vm_area_struct *mpnt;
 204         struct prio_tree_iter iter;
 205         pgoff_t pgoff;
 206
 207         /*
 208          * There are possible user space mappings of this page:
 209          * - VIVT cache: we need to also write back and invalidate all user
 210          *   data in the current VM view associated with this page.
 211          * - aliasing VIPT: we only need to find one mapping of this page.
 212          */
 213         pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
 214
 215         flush_dcache_mmap_lock(mapping);
 216         vma_prio_tree_foreach(mpnt, &iter, &mapping->i_mmap, pgoff, pgoff) {
 217                 unsigned long offset;
 218
 219                 /*
 220                  * If this VMA is not in our MM, we can ignore it.
 221                  */
 222                 if (mpnt->vm_mm != mm)
 223                         continue;
 224                 if (!(mpnt->vm_flags & VM_MAYSHARE))
 225                         continue;
 226                 offset = (pgoff - mpnt->vm_pgoff) << PAGE_SHIFT;
 227                 flush_cache_page(mpnt, mpnt->vm_start + offset, page_to_pfn(page));
 228         }
 229         flush_dcache_mmap_unlock(mapping);
 230 }
 231
 232 #if __LINUX_ARM_ARCH__ >= 6
 233 void __sync_icache_dcache(pte_t pteval)
 234 {
 235         unsigned long pfn;
 236         struct page *page;
 237         struct address_space *mapping;
 238
 239         if (!pte_present_user(pteval))
 240                 return;
 241         if (cache_is_vipt_nonaliasing() && !pte_exec(pteval))
 242                 /* only flush non-aliasing VIPT caches for exec mappings */
 243                 return;
 244         pfn = pte_pfn(pteval);
 245         if (!pfn_valid(pfn))
 246                 return;
 247
 248         page = pfn_to_page(pfn);
 249         if (cache_is_vipt_aliasing())
 250                 mapping = page_mapping(page);
 251         else
 252                 mapping = NULL;
 253
 254         if (!test_and_set_bit(PG_dcache_clean, &page->flags))
 255                 __flush_dcache_page(mapping, page);
 256
 257         if (pte_exec(pteval))
 258                 __flush_icache_all();
 259 }
 260 #endif
 261
 262 /*
 263  * Ensure cache coherency between kernel mapping and userspace mapping
 264  * of this page.
 265  *
 266  * We have three cases to consider:
 267  *  - VIPT non-aliasing cache: fully coherent so nothing required.
 268  *  - VIVT: fully aliasing, so we need to handle every alias in our
 269  *          current VM view.
 270  *  - VIPT aliasing: need to handle one alias in our current VM view.
 271  *
 272  * If we need to handle aliasing:
 273  *  If the page only exists in the page cache and there are no user
 274  *  space mappings, we can be lazy and remember that we may have dirty
 275  *  kernel cache lines for later.  Otherwise, we assume we have
 276  *  aliasing mappings.
 277  *
 278  * Note that we disable the lazy flush for SMP configurations where
 279  * the cache maintenance operations are not automatically broadcasted.
 280  */
 281 void flush_dcache_page(struct page *page)
 282 {
 283         struct address_space *mapping;
 284
 285         /*
 286          * The zero page is never written to, so never has any dirty
 287          * cache lines, and therefore never needs to be flushed.
 288          */
 289         if (page == ZERO_PAGE(0))
 290                 return;
 291
 292         mapping = page_mapping(page);
 293
 294         if (!cache_ops_need_broadcast() &&
 295             mapping && !mapping_mapped(mapping))
 296                 clear_bit(PG_dcache_clean, &page->flags);
 297         else {
 298                 __flush_dcache_page(mapping, page);
 299                 if (mapping && cache_is_vivt())
 300                         __flush_dcache_aliases(mapping, page);
 301                 else if (mapping)
 302                         __flush_icache_all();
 303                 set_bit(PG_dcache_clean, &page->flags);
 304         }
 305 }
 306 EXPORT_SYMBOL(flush_dcache_page);
 307
 308 /*
 309  * Flush an anonymous page so that users of get_user_pages()
 310  * can safely access the data.  The expected sequence is:
 311  *
 312  *  get_user_pages()
 313  *    -> flush_anon_page
 314  *  memcpy() to/from page
 315  *  if written to page, flush_dcache_page()
 316  */
 317 void __flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
 318 {
 319         unsigned long pfn;
 320
 321         /* VIPT non-aliasing caches need do nothing */
 322         if (cache_is_vipt_nonaliasing())
 323                 return;
 324
 325         /*
 326          * Write back and invalidate userspace mapping.
 327          */
 328         pfn = page_to_pfn(page);
 329         if (cache_is_vivt()) {
 330                 flush_cache_page(vma, vmaddr, pfn);
 331         } else {
 332                 /*
 333                  * For aliasing VIPT, we can flush an alias of the
 334                  * userspace address only.
 335                  */
 336                 flush_pfn_alias(pfn, vmaddr);
 337                 __flush_icache_all();
 338         }
 339
 340         /*
 341          * Invalidate kernel mapping.  No data should be contained
 342          * in this mapping of the page.  FIXME: this is overkill
 343          * since we actually ask for a write-back and invalidate.
 344          */
 345         __cpuc_flush_dcache_area(page_address(page), PAGE_SIZE);
 346 }