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 #include <linux/hugetlb.h> 21 22 #include "mm.h" 23 24 #ifdef CONFIG_CPU_CACHE_VIPT 25 26 static void flush_pfn_alias(unsigned long pfn, unsigned long vaddr) 27 { 28 unsigned long to = FLUSH_ALIAS_START + (CACHE_COLOUR(vaddr) << PAGE_SHIFT); 29 const int zero = 0; 30 31 set_top_pte(to, pfn_pte(pfn, PAGE_KERNEL)); 32 33 asm( "mcrr p15, 0, %1, %0, c14\n" 34 " mcr p15, 0, %2, c7, c10, 4" 35 : 36 : "r" (to), "r" (to + PAGE_SIZE - L1_CACHE_BYTES), "r" (zero) 37 : "cc"); 38 } 39 40 static void flush_icache_alias(unsigned long pfn, unsigned long vaddr, unsigned long len) 41 { 42 unsigned long va = FLUSH_ALIAS_START + (CACHE_COLOUR(vaddr) << PAGE_SHIFT); 43 unsigned long offset = vaddr & (PAGE_SIZE - 1); 44 unsigned long to; 45 46 set_top_pte(va, pfn_pte(pfn, PAGE_KERNEL)); 47 to = va + offset; 48 flush_icache_range(to, to + len); 49 } 50 51 void flush_cache_mm(struct mm_struct *mm) 52 { 53 if (cache_is_vivt()) { 54 vivt_flush_cache_mm(mm); 55 return; 56 } 57 58 if (cache_is_vipt_aliasing()) { 59 asm( "mcr p15, 0, %0, c7, c14, 0\n" 60 " mcr p15, 0, %0, c7, c10, 4" 61 : 62 : "r" (0) 63 : "cc"); 64 } 65 } 66 67 void flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned long end) 68 { 69 if (cache_is_vivt()) { 70 vivt_flush_cache_range(vma, start, end); 71 return; 72 } 73 74 if (cache_is_vipt_aliasing()) { 75 asm( "mcr p15, 0, %0, c7, c14, 0\n" 76 " mcr p15, 0, %0, c7, c10, 4" 77 : 78 : "r" (0) 79 : "cc"); 80 } 81 82 if (vma->vm_flags & VM_EXEC) 83 __flush_icache_all(); 84 } 85 86 void flush_cache_page(struct vm_area_struct *vma, unsigned long user_addr, unsigned long pfn) 87 { 88 if (cache_is_vivt()) { 89 vivt_flush_cache_page(vma, user_addr, pfn); 90 return; 91 } 92 93 if (cache_is_vipt_aliasing()) { 94 flush_pfn_alias(pfn, user_addr); 95 __flush_icache_all(); 96 } 97 98 if (vma->vm_flags & VM_EXEC && icache_is_vivt_asid_tagged()) 99 __flush_icache_all(); 100 } 101 102 #else 103 #define flush_pfn_alias(pfn,vaddr) do { } while (0) 104 #define flush_icache_alias(pfn,vaddr,len) do { } while (0) 105 #endif 106 107 static void flush_ptrace_access_other(void *args) 108 { 109 __flush_icache_all(); 110 } 111 112 static 113 void flush_ptrace_access(struct vm_area_struct *vma, struct page *page, 114 unsigned long uaddr, void *kaddr, unsigned long len) 115 { 116 if (cache_is_vivt()) { 117 if (cpumask_test_cpu(smp_processor_id(), mm_cpumask(vma->vm_mm))) { 118 unsigned long addr = (unsigned long)kaddr; 119 __cpuc_coherent_kern_range(addr, addr + len); 120 } 121 return; 122 } 123 124 if (cache_is_vipt_aliasing()) { 125 flush_pfn_alias(page_to_pfn(page), uaddr); 126 __flush_icache_all(); 127 return; 128 } 129 130 /* VIPT non-aliasing D-cache */ 131 if (vma->vm_flags & VM_EXEC) { 132 unsigned long addr = (unsigned long)kaddr; 133 if (icache_is_vipt_aliasing()) 134 flush_icache_alias(page_to_pfn(page), uaddr, len); 135 else 136 __cpuc_coherent_kern_range(addr, addr + len); 137 if (cache_ops_need_broadcast()) 138 smp_call_function(flush_ptrace_access_other, 139 NULL, 1); 140 } 141 } 142 143 /* 144 * Copy user data from/to a page which is mapped into a different 145 * processes address space. Really, we want to allow our "user 146 * space" model to handle this. 147 * 148 * Note that this code needs to run on the current CPU. 149 */ 150 void copy_to_user_page(struct vm_area_struct *vma, struct page *page, 151 unsigned long uaddr, void *dst, const void *src, 152 unsigned long len) 153 { 154 #ifdef CONFIG_SMP 155 preempt_disable(); 156 #endif 157 memcpy(dst, src, len); 158 flush_ptrace_access(vma, page, uaddr, dst, len); 159 #ifdef CONFIG_SMP 160 preempt_enable(); 161 #endif 162 } 163 164 void __flush_dcache_page(struct address_space *mapping, struct page *page) 165 { 166 /* 167 * Writeback any data associated with the kernel mapping of this 168 * page. This ensures that data in the physical page is mutually 169 * coherent with the kernels mapping. 170 */ 171 if (!PageHighMem(page)) { 172 size_t page_size = PAGE_SIZE << compound_order(page); 173 __cpuc_flush_dcache_area(page_address(page), page_size); 174 } else { 175 unsigned long i; 176 if (cache_is_vipt_nonaliasing()) { 177 for (i = 0; i < (1 << compound_order(page)); i++) { 178 void *addr = kmap_atomic(page); 179 __cpuc_flush_dcache_area(addr, PAGE_SIZE); 180 kunmap_atomic(addr); 181 } 182 } else { 183 for (i = 0; i < (1 << compound_order(page)); i++) { 184 void *addr = kmap_high_get(page); 185 if (addr) { 186 __cpuc_flush_dcache_area(addr, PAGE_SIZE); 187 kunmap_high(page); 188 } 189 } 190 } 191 } 192 193 /* 194 * If this is a page cache page, and we have an aliasing VIPT cache, 195 * we only need to do one flush - which would be at the relevant 196 * userspace colour, which is congruent with page->index. 197 */ 198 if (mapping && cache_is_vipt_aliasing()) 199 flush_pfn_alias(page_to_pfn(page), 200 page->index << PAGE_CACHE_SHIFT); 201 } 202 203 static void __flush_dcache_aliases(struct address_space *mapping, struct page *page) 204 { 205 struct mm_struct *mm = current->active_mm; 206 struct vm_area_struct *mpnt; 207 pgoff_t pgoff; 208 209 /* 210 * There are possible user space mappings of this page: 211 * - VIVT cache: we need to also write back and invalidate all user 212 * data in the current VM view associated with this page. 213 * - aliasing VIPT: we only need to find one mapping of this page. 214 */ 215 pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); 216 217 flush_dcache_mmap_lock(mapping); 218 vma_interval_tree_foreach(mpnt, &mapping->i_mmap, pgoff, pgoff) { 219 unsigned long offset; 220 221 /* 222 * If this VMA is not in our MM, we can ignore it. 223 */ 224 if (mpnt->vm_mm != mm) 225 continue; 226 if (!(mpnt->vm_flags & VM_MAYSHARE)) 227 continue; 228 offset = (pgoff - mpnt->vm_pgoff) << PAGE_SHIFT; 229 flush_cache_page(mpnt, mpnt->vm_start + offset, page_to_pfn(page)); 230 } 231 flush_dcache_mmap_unlock(mapping); 232 } 233 234 #if __LINUX_ARM_ARCH__ >= 6 235 void __sync_icache_dcache(pte_t pteval) 236 { 237 unsigned long pfn; 238 struct page *page; 239 struct address_space *mapping; 240 241 if (cache_is_vipt_nonaliasing() && !pte_exec(pteval)) 242 /* only flush non-aliasing VIPT caches for exec mappings */ 243 return; 244 pfn = pte_pfn(pteval); 245 if (!pfn_valid(pfn)) 246 return; 247 248 page = pfn_to_page(pfn); 249 if (cache_is_vipt_aliasing()) 250 mapping = page_mapping(page); 251 else 252 mapping = NULL; 253 254 if (!test_and_set_bit(PG_dcache_clean, &page->flags)) 255 __flush_dcache_page(mapping, page); 256 257 if (pte_exec(pteval)) 258 __flush_icache_all(); 259 } 260 #endif 261 262 /* 263 * Ensure cache coherency between kernel mapping and userspace mapping 264 * of this page. 265 * 266 * We have three cases to consider: 267 * - VIPT non-aliasing cache: fully coherent so nothing required. 268 * - VIVT: fully aliasing, so we need to handle every alias in our 269 * current VM view. 270 * - VIPT aliasing: need to handle one alias in our current VM view. 271 * 272 * If we need to handle aliasing: 273 * If the page only exists in the page cache and there are no user 274 * space mappings, we can be lazy and remember that we may have dirty 275 * kernel cache lines for later. Otherwise, we assume we have 276 * aliasing mappings. 277 * 278 * Note that we disable the lazy flush for SMP configurations where 279 * the cache maintenance operations are not automatically broadcasted. 280 */ 281 void flush_dcache_page(struct page *page) 282 { 283 struct address_space *mapping; 284 285 /* 286 * The zero page is never written to, so never has any dirty 287 * cache lines, and therefore never needs to be flushed. 288 */ 289 if (page == ZERO_PAGE(0)) 290 return; 291 292 mapping = page_mapping(page); 293 294 if (!cache_ops_need_broadcast() && 295 mapping && !page_mapped(page)) 296 clear_bit(PG_dcache_clean, &page->flags); 297 else { 298 __flush_dcache_page(mapping, page); 299 if (mapping && cache_is_vivt()) 300 __flush_dcache_aliases(mapping, page); 301 else if (mapping) 302 __flush_icache_all(); 303 set_bit(PG_dcache_clean, &page->flags); 304 } 305 } 306 EXPORT_SYMBOL(flush_dcache_page); 307 308 /* 309 * Ensure cache coherency for the kernel mapping of this page. We can 310 * assume that the page is pinned via kmap. 311 * 312 * If the page only exists in the page cache and there are no user 313 * space mappings, this is a no-op since the page was already marked 314 * dirty at creation. Otherwise, we need to flush the dirty kernel 315 * cache lines directly. 316 */ 317 void flush_kernel_dcache_page(struct page *page) 318 { 319 if (cache_is_vivt() || cache_is_vipt_aliasing()) { 320 struct address_space *mapping; 321 322 mapping = page_mapping(page); 323 324 if (!mapping || mapping_mapped(mapping)) { 325 void *addr; 326 327 addr = page_address(page); 328 /* 329 * kmap_atomic() doesn't set the page virtual 330 * address for highmem pages, and 331 * kunmap_atomic() takes care of cache 332 * flushing already. 333 */ 334 if (!IS_ENABLED(CONFIG_HIGHMEM) || addr) 335 __cpuc_flush_dcache_area(addr, PAGE_SIZE); 336 } 337 } 338 } 339 EXPORT_SYMBOL(flush_kernel_dcache_page); 340 341 /* 342 * Flush an anonymous page so that users of get_user_pages() 343 * can safely access the data. The expected sequence is: 344 * 345 * get_user_pages() 346 * -> flush_anon_page 347 * memcpy() to/from page 348 * if written to page, flush_dcache_page() 349 */ 350 void __flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr) 351 { 352 unsigned long pfn; 353 354 /* VIPT non-aliasing caches need do nothing */ 355 if (cache_is_vipt_nonaliasing()) 356 return; 357 358 /* 359 * Write back and invalidate userspace mapping. 360 */ 361 pfn = page_to_pfn(page); 362 if (cache_is_vivt()) { 363 flush_cache_page(vma, vmaddr, pfn); 364 } else { 365 /* 366 * For aliasing VIPT, we can flush an alias of the 367 * userspace address only. 368 */ 369 flush_pfn_alias(pfn, vmaddr); 370 __flush_icache_all(); 371 } 372 373 /* 374 * Invalidate kernel mapping. No data should be contained 375 * in this mapping of the page. FIXME: this is overkill 376 * since we actually ask for a write-back and invalidate. 377 */ 378 __cpuc_flush_dcache_area(page_address(page), PAGE_SIZE); 379 } 380