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         pgoff_t pgoff;
 200
 201         /*
 202          * There are possible user space mappings of this page:
 203          * - VIVT cache: we need to also write back and invalidate all user
 204          *   data in the current VM view associated with this page.
 205          * - aliasing VIPT: we only need to find one mapping of this page.
 206          */
 207         pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
 208
 209         flush_dcache_mmap_lock(mapping);
 210         vma_interval_tree_foreach(mpnt, &mapping->i_mmap, pgoff, pgoff) {
 211                 unsigned long offset;
 212
 213                 /*
 214                  * If this VMA is not in our MM, we can ignore it.
 215                  */
 216                 if (mpnt->vm_mm != mm)
 217                         continue;
 218                 if (!(mpnt->vm_flags & VM_MAYSHARE))
 219                         continue;
 220                 offset = (pgoff - mpnt->vm_pgoff) << PAGE_SHIFT;
 221                 flush_cache_page(mpnt, mpnt->vm_start + offset, page_to_pfn(page));
 222         }
 223         flush_dcache_mmap_unlock(mapping);
 224 }
 225
 226 #if __LINUX_ARM_ARCH__ >= 6
 227 void __sync_icache_dcache(pte_t pteval)
 228 {
 229         unsigned long pfn;
 230         struct page *page;
 231         struct address_space *mapping;
 232
 233         if (cache_is_vipt_nonaliasing() && !pte_exec(pteval))
 234                 /* only flush non-aliasing VIPT caches for exec mappings */
 235                 return;
 236         pfn = pte_pfn(pteval);
 237         if (!pfn_valid(pfn))
 238                 return;
 239
 240         page = pfn_to_page(pfn);
 241         if (cache_is_vipt_aliasing())
 242                 mapping = page_mapping(page);
 243         else
 244                 mapping = NULL;
 245
 246         if (!test_and_set_bit(PG_dcache_clean, &page->flags))
 247                 __flush_dcache_page(mapping, page);
 248
 249         if (pte_exec(pteval))
 250                 __flush_icache_all();
 251 }
 252 #endif
 253
 254 /*
 255  * Ensure cache coherency between kernel mapping and userspace mapping
 256  * of this page.
 257  *
 258  * We have three cases to consider:
 259  *  - VIPT non-aliasing cache: fully coherent so nothing required.
 260  *  - VIVT: fully aliasing, so we need to handle every alias in our
 261  *          current VM view.
 262  *  - VIPT aliasing: need to handle one alias in our current VM view.
 263  *
 264  * If we need to handle aliasing:
 265  *  If the page only exists in the page cache and there are no user
 266  *  space mappings, we can be lazy and remember that we may have dirty
 267  *  kernel cache lines for later.  Otherwise, we assume we have
 268  *  aliasing mappings.
 269  *
 270  * Note that we disable the lazy flush for SMP configurations where
 271  * the cache maintenance operations are not automatically broadcasted.
 272  */
 273 void flush_dcache_page(struct page *page)
 274 {
 275         struct address_space *mapping;
 276
 277         /*
 278          * The zero page is never written to, so never has any dirty
 279          * cache lines, and therefore never needs to be flushed.
 280          */
 281         if (page == ZERO_PAGE(0))
 282                 return;
 283
 284         mapping = page_mapping(page);
 285
 286         if (!cache_ops_need_broadcast() &&
 287             mapping && !mapping_mapped(mapping))
 288                 clear_bit(PG_dcache_clean, &page->flags);
 289         else {
 290                 __flush_dcache_page(mapping, page);
 291                 if (mapping && cache_is_vivt())
 292                         __flush_dcache_aliases(mapping, page);
 293                 else if (mapping)
 294                         __flush_icache_all();
 295                 set_bit(PG_dcache_clean, &page->flags);
 296         }
 297 }
 298 EXPORT_SYMBOL(flush_dcache_page);
 299
 300 /*
 301  * Flush an anonymous page so that users of get_user_pages()
 302  * can safely access the data.  The expected sequence is:
 303  *
 304  *  get_user_pages()
 305  *    -> flush_anon_page
 306  *  memcpy() to/from page
 307  *  if written to page, flush_dcache_page()
 308  */
 309 void __flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
 310 {
 311         unsigned long pfn;
 312
 313         /* VIPT non-aliasing caches need do nothing */
 314         if (cache_is_vipt_nonaliasing())
 315                 return;
 316
 317         /*
 318          * Write back and invalidate userspace mapping.
 319          */
 320         pfn = page_to_pfn(page);
 321         if (cache_is_vivt()) {
 322                 flush_cache_page(vma, vmaddr, pfn);
 323         } else {
 324                 /*
 325                  * For aliasing VIPT, we can flush an alias of the
 326                  * userspace address only.
 327                  */
 328                 flush_pfn_alias(pfn, vmaddr);
 329                 __flush_icache_all();
 330         }
 331
 332         /*
 333          * Invalidate kernel mapping.  No data should be contained
 334          * in this mapping of the page.  FIXME: this is overkill
 335          * since we actually ask for a write-back and invalidate.
 336          */
 337         __cpuc_flush_dcache_area(page_address(page), PAGE_SIZE);
 338 }