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
  14 #include <asm/cacheflush.h>
  15 #include <asm/system.h>
  16 #include <asm/tlbflush.h>
  17
  18 #include "mm.h"
  19
  20 #ifdef CONFIG_CPU_CACHE_VIPT
  21
  22 #define ALIAS_FLUSH_START       0xffff4000
  23
  24 static void flush_pfn_alias(unsigned long pfn, unsigned long vaddr)
  25 {
  26         unsigned long to = ALIAS_FLUSH_START + (CACHE_COLOUR(vaddr) << PAGE_SHIFT);
  27         const int zero = 0;
  28
  29         set_pte_ext(TOP_PTE(to), pfn_pte(pfn, PAGE_KERNEL), 0);
  30         flush_tlb_kernel_page(to);
  31
  32         asm(    "mcrr   p15, 0, %1, %0, c14\n"
  33         "       mcr     p15, 0, %2, c7, c10, 4\n"
  34         "       mcr     p15, 0, %2, c7, c5, 0\n"
  35             :
  36             : "r" (to), "r" (to + PAGE_SIZE - L1_CACHE_BYTES), "r" (zero)
  37             : "cc");
  38 }
  39
  40 void flush_cache_mm(struct mm_struct *mm)
  41 {
  42         if (cache_is_vivt()) {
  43                 if (cpu_isset(smp_processor_id(), mm->cpu_vm_mask))
  44                         __cpuc_flush_user_all();
  45                 return;
  46         }
  47
  48         if (cache_is_vipt_aliasing()) {
  49                 asm(    "mcr    p15, 0, %0, c7, c14, 0\n"
  50                 "       mcr     p15, 0, %0, c7, c5, 0\n"
  51                 "       mcr     p15, 0, %0, c7, c10, 4"
  52                     :
  53                     : "r" (0)
  54                     : "cc");
  55         }
  56 }
  57
  58 void flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned long end)
  59 {
  60         if (cache_is_vivt()) {
  61                 if (cpu_isset(smp_processor_id(), vma->vm_mm->cpu_vm_mask))
  62                         __cpuc_flush_user_range(start & PAGE_MASK, PAGE_ALIGN(end),
  63                                                 vma->vm_flags);
  64                 return;
  65         }
  66
  67         if (cache_is_vipt_aliasing()) {
  68                 asm(    "mcr    p15, 0, %0, c7, c14, 0\n"
  69                 "       mcr     p15, 0, %0, c7, c5, 0\n"
  70                 "       mcr     p15, 0, %0, c7, c10, 4"
  71                     :
  72                     : "r" (0)
  73                     : "cc");
  74         }
  75 }
  76
  77 void flush_cache_page(struct vm_area_struct *vma, unsigned long user_addr, unsigned long pfn)
  78 {
  79         if (cache_is_vivt()) {
  80                 if (cpu_isset(smp_processor_id(), vma->vm_mm->cpu_vm_mask)) {
  81                         unsigned long addr = user_addr & PAGE_MASK;
  82                         __cpuc_flush_user_range(addr, addr + PAGE_SIZE, vma->vm_flags);
  83                 }
  84                 return;
  85         }
  86
  87         if (cache_is_vipt_aliasing())
  88                 flush_pfn_alias(pfn, user_addr);
  89 }
  90
  91 void flush_ptrace_access(struct vm_area_struct *vma, struct page *page,
  92                          unsigned long uaddr, void *kaddr,
  93                          unsigned long len, int write)
  94 {
  95         if (cache_is_vivt()) {
  96                 if (cpu_isset(smp_processor_id(), vma->vm_mm->cpu_vm_mask)) {
  97                         unsigned long addr = (unsigned long)kaddr;
  98                         __cpuc_coherent_kern_range(addr, addr + len);
  99                 }
 100                 return;
 101         }
 102
 103         if (cache_is_vipt_aliasing()) {
 104                 flush_pfn_alias(page_to_pfn(page), uaddr);
 105                 return;
 106         }
 107
 108         /* VIPT non-aliasing cache */
 109         if (cpu_isset(smp_processor_id(), vma->vm_mm->cpu_vm_mask) &&
 110             vma->vm_flags & VM_EXEC) {
 111                 unsigned long addr = (unsigned long)kaddr;
 112                 /* only flushing the kernel mapping on non-aliasing VIPT */
 113                 __cpuc_coherent_kern_range(addr, addr + len);
 114         }
 115 }
 116 #else
 117 #define flush_pfn_alias(pfn,vaddr)      do { } while (0)
 118 #endif
 119
 120 void __flush_dcache_page(struct address_space *mapping, struct page *page)
 121 {
 122         /*
 123          * Writeback any data associated with the kernel mapping of this
 124          * page.  This ensures that data in the physical page is mutually
 125          * coherent with the kernels mapping.
 126          */
 127         __cpuc_flush_dcache_page(page_address(page));
 128
 129         /*
 130          * If this is a page cache page, and we have an aliasing VIPT cache,
 131          * we only need to do one flush - which would be at the relevant
 132          * userspace colour, which is congruent with page->index.
 133          */
 134         if (mapping && cache_is_vipt_aliasing())
 135                 flush_pfn_alias(page_to_pfn(page),
 136                                 page->index << PAGE_CACHE_SHIFT);
 137 }
 138
 139 static void __flush_dcache_aliases(struct address_space *mapping, struct page *page)
 140 {
 141         struct mm_struct *mm = current->active_mm;
 142         struct vm_area_struct *mpnt;
 143         struct prio_tree_iter iter;
 144         pgoff_t pgoff;
 145
 146         /*
 147          * There are possible user space mappings of this page:
 148          * - VIVT cache: we need to also write back and invalidate all user
 149          *   data in the current VM view associated with this page.
 150          * - aliasing VIPT: we only need to find one mapping of this page.
 151          */
 152         pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
 153
 154         flush_dcache_mmap_lock(mapping);
 155         vma_prio_tree_foreach(mpnt, &iter, &mapping->i_mmap, pgoff, pgoff) {
 156                 unsigned long offset;
 157
 158                 /*
 159                  * If this VMA is not in our MM, we can ignore it.
 160                  */
 161                 if (mpnt->vm_mm != mm)
 162                         continue;
 163                 if (!(mpnt->vm_flags & VM_MAYSHARE))
 164                         continue;
 165                 offset = (pgoff - mpnt->vm_pgoff) << PAGE_SHIFT;
 166                 flush_cache_page(mpnt, mpnt->vm_start + offset, page_to_pfn(page));
 167         }
 168         flush_dcache_mmap_unlock(mapping);
 169 }
 170
 171 /*
 172  * Ensure cache coherency between kernel mapping and userspace mapping
 173  * of this page.
 174  *
 175  * We have three cases to consider:
 176  *  - VIPT non-aliasing cache: fully coherent so nothing required.
 177  *  - VIVT: fully aliasing, so we need to handle every alias in our
 178  *          current VM view.
 179  *  - VIPT aliasing: need to handle one alias in our current VM view.
 180  *
 181  * If we need to handle aliasing:
 182  *  If the page only exists in the page cache and there are no user
 183  *  space mappings, we can be lazy and remember that we may have dirty
 184  *  kernel cache lines for later.  Otherwise, we assume we have
 185  *  aliasing mappings.
 186  *
 187  * Note that we disable the lazy flush for SMP.
 188  */
 189 void flush_dcache_page(struct page *page)
 190 {
 191         struct address_space *mapping = page_mapping(page);
 192
 193 #ifndef CONFIG_SMP
 194         if (mapping && !mapping_mapped(mapping))
 195                 set_bit(PG_dcache_dirty, &page->flags);
 196         else
 197 #endif
 198         {
 199                 __flush_dcache_page(mapping, page);
 200                 if (mapping && cache_is_vivt())
 201                         __flush_dcache_aliases(mapping, page);
 202         }
 203 }
 204 EXPORT_SYMBOL(flush_dcache_page);
 205
 206 /*
 207  * Flush an anonymous page so that users of get_user_pages()
 208  * can safely access the data.  The expected sequence is:
 209  *
 210  *  get_user_pages()
 211  *    -> flush_anon_page
 212  *  memcpy() to/from page
 213  *  if written to page, flush_dcache_page()
 214  */
 215 void __flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
 216 {
 217         unsigned long pfn;
 218
 219         /* VIPT non-aliasing caches need do nothing */
 220         if (cache_is_vipt_nonaliasing())
 221                 return;
 222
 223         /*
 224          * Write back and invalidate userspace mapping.
 225          */
 226         pfn = page_to_pfn(page);
 227         if (cache_is_vivt()) {
 228                 flush_cache_page(vma, vmaddr, pfn);
 229         } else {
 230                 /*
 231                  * For aliasing VIPT, we can flush an alias of the
 232                  * userspace address only.
 233                  */
 234                 flush_pfn_alias(pfn, vmaddr);
 235         }
 236
 237         /*
 238          * Invalidate kernel mapping.  No data should be contained
 239          * in this mapping of the page.  FIXME: this is overkill
 240          * since we actually ask for a write-back and invalidate.
 241          */
 242         __cpuc_flush_dcache_page(page_address(page));
 243 }