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/cachetype.h>
  16 #include <asm/system.h>
  17 #include <asm/tlbflush.h>
  18
  19 #include "mm.h"
  20
  21 #ifdef CONFIG_CPU_CACHE_VIPT
  22
  23 #define ALIAS_FLUSH_START       0xffff4000
  24
  25 static void flush_pfn_alias(unsigned long pfn, unsigned long vaddr)
  26 {
  27         unsigned long to = ALIAS_FLUSH_START + (CACHE_COLOUR(vaddr) << PAGE_SHIFT);
  28         const int zero = 0;
  29
  30         set_pte_ext(TOP_PTE(to), pfn_pte(pfn, PAGE_KERNEL), 0);
  31         flush_tlb_kernel_page(to);
  32
  33         asm(    "mcrr   p15, 0, %1, %0, c14\n"
  34         "       mcr     p15, 0, %2, c7, c10, 4\n"
  35         "       mcr     p15, 0, %2, c7, c5, 0\n"
  36             :
  37             : "r" (to), "r" (to + PAGE_SIZE - L1_CACHE_BYTES), "r" (zero)
  38             : "cc");
  39 }
  40
  41 void flush_cache_mm(struct mm_struct *mm)
  42 {
  43         if (cache_is_vivt()) {
  44                 if (cpu_isset(smp_processor_id(), mm->cpu_vm_mask))
  45                         __cpuc_flush_user_all();
  46                 return;
  47         }
  48
  49         if (cache_is_vipt_aliasing()) {
  50                 asm(    "mcr    p15, 0, %0, c7, c14, 0\n"
  51                 "       mcr     p15, 0, %0, c7, c5, 0\n"
  52                 "       mcr     p15, 0, %0, c7, c10, 4"
  53                     :
  54                     : "r" (0)
  55                     : "cc");
  56         }
  57 }
  58
  59 void flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned long end)
  60 {
  61         if (cache_is_vivt()) {
  62                 if (cpu_isset(smp_processor_id(), vma->vm_mm->cpu_vm_mask))
  63                         __cpuc_flush_user_range(start & PAGE_MASK, PAGE_ALIGN(end),
  64                                                 vma->vm_flags);
  65                 return;
  66         }
  67
  68         if (cache_is_vipt_aliasing()) {
  69                 asm(    "mcr    p15, 0, %0, c7, c14, 0\n"
  70                 "       mcr     p15, 0, %0, c7, c5, 0\n"
  71                 "       mcr     p15, 0, %0, c7, c10, 4"
  72                     :
  73                     : "r" (0)
  74                     : "cc");
  75         }
  76 }
  77
  78 void flush_cache_page(struct vm_area_struct *vma, unsigned long user_addr, unsigned long pfn)
  79 {
  80         if (cache_is_vivt()) {
  81                 if (cpu_isset(smp_processor_id(), vma->vm_mm->cpu_vm_mask)) {
  82                         unsigned long addr = user_addr & PAGE_MASK;
  83                         __cpuc_flush_user_range(addr, addr + PAGE_SIZE, vma->vm_flags);
  84                 }
  85                 return;
  86         }
  87
  88         if (cache_is_vipt_aliasing())
  89                 flush_pfn_alias(pfn, user_addr);
  90 }
  91
  92 void flush_ptrace_access(struct vm_area_struct *vma, struct page *page,
  93                          unsigned long uaddr, void *kaddr,
  94                          unsigned long len, int write)
  95 {
  96         if (cache_is_vivt()) {
  97                 if (cpu_isset(smp_processor_id(), vma->vm_mm->cpu_vm_mask)) {
  98                         unsigned long addr = (unsigned long)kaddr;
  99                         __cpuc_coherent_kern_range(addr, addr + len);
 100                 }
 101                 return;
 102         }
 103
 104         if (cache_is_vipt_aliasing()) {
 105                 flush_pfn_alias(page_to_pfn(page), uaddr);
 106                 return;
 107         }
 108
 109         /* VIPT non-aliasing cache */
 110         if (cpu_isset(smp_processor_id(), vma->vm_mm->cpu_vm_mask) &&
 111             vma->vm_flags & VM_EXEC) {
 112                 unsigned long addr = (unsigned long)kaddr;
 113                 /* only flushing the kernel mapping on non-aliasing VIPT */
 114                 __cpuc_coherent_kern_range(addr, addr + len);
 115         }
 116 }
 117 #else
 118 #define flush_pfn_alias(pfn,vaddr)      do { } while (0)
 119 #endif
 120
 121 void __flush_dcache_page(struct address_space *mapping, struct page *page)
 122 {
 123         /*
 124          * Writeback any data associated with the kernel mapping of this
 125          * page.  This ensures that data in the physical page is mutually
 126          * coherent with the kernels mapping.
 127          */
 128         __cpuc_flush_dcache_page(page_address(page));
 129
 130         /*
 131          * If this is a page cache page, and we have an aliasing VIPT cache,
 132          * we only need to do one flush - which would be at the relevant
 133          * userspace colour, which is congruent with page->index.
 134          */
 135         if (mapping && cache_is_vipt_aliasing())
 136                 flush_pfn_alias(page_to_pfn(page),
 137                                 page->index << PAGE_CACHE_SHIFT);
 138 }
 139
 140 static void __flush_dcache_aliases(struct address_space *mapping, struct page *page)
 141 {
 142         struct mm_struct *mm = current->active_mm;
 143         struct vm_area_struct *mpnt;
 144         struct prio_tree_iter iter;
 145         pgoff_t pgoff;
 146
 147         /*
 148          * There are possible user space mappings of this page:
 149          * - VIVT cache: we need to also write back and invalidate all user
 150          *   data in the current VM view associated with this page.
 151          * - aliasing VIPT: we only need to find one mapping of this page.
 152          */
 153         pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
 154
 155         flush_dcache_mmap_lock(mapping);
 156         vma_prio_tree_foreach(mpnt, &iter, &mapping->i_mmap, pgoff, pgoff) {
 157                 unsigned long offset;
 158
 159                 /*
 160                  * If this VMA is not in our MM, we can ignore it.
 161                  */
 162                 if (mpnt->vm_mm != mm)
 163                         continue;
 164                 if (!(mpnt->vm_flags & VM_MAYSHARE))
 165                         continue;
 166                 offset = (pgoff - mpnt->vm_pgoff) << PAGE_SHIFT;
 167                 flush_cache_page(mpnt, mpnt->vm_start + offset, page_to_pfn(page));
 168         }
 169         flush_dcache_mmap_unlock(mapping);
 170 }
 171
 172 /*
 173  * Ensure cache coherency between kernel mapping and userspace mapping
 174  * of this page.
 175  *
 176  * We have three cases to consider:
 177  *  - VIPT non-aliasing cache: fully coherent so nothing required.
 178  *  - VIVT: fully aliasing, so we need to handle every alias in our
 179  *          current VM view.
 180  *  - VIPT aliasing: need to handle one alias in our current VM view.
 181  *
 182  * If we need to handle aliasing:
 183  *  If the page only exists in the page cache and there are no user
 184  *  space mappings, we can be lazy and remember that we may have dirty
 185  *  kernel cache lines for later.  Otherwise, we assume we have
 186  *  aliasing mappings.
 187  *
 188  * Note that we disable the lazy flush for SMP.
 189  */
 190 void flush_dcache_page(struct page *page)
 191 {
 192         struct address_space *mapping = page_mapping(page);
 193
 194 #ifndef CONFIG_SMP
 195         if (mapping && !mapping_mapped(mapping))
 196                 set_bit(PG_dcache_dirty, &page->flags);
 197         else
 198 #endif
 199         {
 200                 __flush_dcache_page(mapping, page);
 201                 if (mapping && cache_is_vivt())
 202                         __flush_dcache_aliases(mapping, page);
 203                 else if (mapping)
 204                         __flush_icache_all();
 205         }
 206 }
 207 EXPORT_SYMBOL(flush_dcache_page);
 208
 209 /*
 210  * Flush an anonymous page so that users of get_user_pages()
 211  * can safely access the data.  The expected sequence is:
 212  *
 213  *  get_user_pages()
 214  *    -> flush_anon_page
 215  *  memcpy() to/from page
 216  *  if written to page, flush_dcache_page()
 217  */
 218 void __flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
 219 {
 220         unsigned long pfn;
 221
 222         /* VIPT non-aliasing caches need do nothing */
 223         if (cache_is_vipt_nonaliasing())
 224                 return;
 225
 226         /*
 227          * Write back and invalidate userspace mapping.
 228          */
 229         pfn = page_to_pfn(page);
 230         if (cache_is_vivt()) {
 231                 flush_cache_page(vma, vmaddr, pfn);
 232         } else {
 233                 /*
 234                  * For aliasing VIPT, we can flush an alias of the
 235                  * userspace address only.
 236                  */
 237                 flush_pfn_alias(pfn, vmaddr);
 238         }
 239
 240         /*
 241          * Invalidate kernel mapping.  No data should be contained
 242          * in this mapping of the page.  FIXME: this is overkill
 243          * since we actually ask for a write-back and invalidate.
 244          */
 245         __cpuc_flush_dcache_page(page_address(page));
 246 }