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 } 339