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