1 /************************************************************************** 2 * 3 * Copyright (c) 2006-2007 Tungsten Graphics, Inc., Cedar Park, TX., USA 4 * All Rights Reserved. 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a 7 * copy of this software and associated documentation files (the 8 * "Software"), to deal in the Software without restriction, including 9 * without limitation the rights to use, copy, modify, merge, publish, 10 * distribute, sub license, and/or sell copies of the Software, and to 11 * permit persons to whom the Software is furnished to do so, subject to 12 * the following conditions: 13 * 14 * The above copyright notice and this permission notice (including the 15 * next paragraph) shall be included in all copies or substantial portions 16 * of the Software. 17 * 18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 20 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL 21 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, 22 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR 23 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE 24 * USE OR OTHER DEALINGS IN THE SOFTWARE. 25 * 26 **************************************************************************/ 27 /* 28 * Authors: Thomas Hellström <thomas-at-tungstengraphics-dot-com> 29 */ 30 31 #include <linux/dma-buf-map.h> 32 #include <linux/export.h> 33 #include <linux/highmem.h> 34 #include <linux/mem_encrypt.h> 35 #include <xen/xen.h> 36 37 #include <drm/drm_cache.h> 38 39 /* A small bounce buffer that fits on the stack. */ 40 #define MEMCPY_BOUNCE_SIZE 128 41 42 #if defined(CONFIG_X86) 43 #include <asm/smp.h> 44 45 /* 46 * clflushopt is an unordered instruction which needs fencing with mfence or 47 * sfence to avoid ordering issues. For drm_clflush_page this fencing happens 48 * in the caller. 49 */ 50 static void 51 drm_clflush_page(struct page *page) 52 { 53 uint8_t *page_virtual; 54 unsigned int i; 55 const int size = boot_cpu_data.x86_clflush_size; 56 57 if (unlikely(page == NULL)) 58 return; 59 60 page_virtual = kmap_atomic(page); 61 for (i = 0; i < PAGE_SIZE; i += size) 62 clflushopt(page_virtual + i); 63 kunmap_atomic(page_virtual); 64 } 65 66 static void drm_cache_flush_clflush(struct page *pages[], 67 unsigned long num_pages) 68 { 69 unsigned long i; 70 71 mb(); /*Full memory barrier used before so that CLFLUSH is ordered*/ 72 for (i = 0; i < num_pages; i++) 73 drm_clflush_page(*pages++); 74 mb(); /*Also used after CLFLUSH so that all cache is flushed*/ 75 } 76 #endif 77 78 /** 79 * drm_clflush_pages - Flush dcache lines of a set of pages. 80 * @pages: List of pages to be flushed. 81 * @num_pages: Number of pages in the array. 82 * 83 * Flush every data cache line entry that points to an address belonging 84 * to a page in the array. 85 */ 86 void 87 drm_clflush_pages(struct page *pages[], unsigned long num_pages) 88 { 89 90 #if defined(CONFIG_X86) 91 if (static_cpu_has(X86_FEATURE_CLFLUSH)) { 92 drm_cache_flush_clflush(pages, num_pages); 93 return; 94 } 95 96 if (wbinvd_on_all_cpus()) 97 pr_err("Timed out waiting for cache flush\n"); 98 99 #elif defined(__powerpc__) 100 unsigned long i; 101 102 for (i = 0; i < num_pages; i++) { 103 struct page *page = pages[i]; 104 void *page_virtual; 105 106 if (unlikely(page == NULL)) 107 continue; 108 109 page_virtual = kmap_atomic(page); 110 flush_dcache_range((unsigned long)page_virtual, 111 (unsigned long)page_virtual + PAGE_SIZE); 112 kunmap_atomic(page_virtual); 113 } 114 #else 115 pr_err("Architecture has no drm_cache.c support\n"); 116 WARN_ON_ONCE(1); 117 #endif 118 } 119 EXPORT_SYMBOL(drm_clflush_pages); 120 121 /** 122 * drm_clflush_sg - Flush dcache lines pointing to a scather-gather. 123 * @st: struct sg_table. 124 * 125 * Flush every data cache line entry that points to an address in the 126 * sg. 127 */ 128 void 129 drm_clflush_sg(struct sg_table *st) 130 { 131 #if defined(CONFIG_X86) 132 if (static_cpu_has(X86_FEATURE_CLFLUSH)) { 133 struct sg_page_iter sg_iter; 134 135 mb(); /*CLFLUSH is ordered only by using memory barriers*/ 136 for_each_sgtable_page(st, &sg_iter, 0) 137 drm_clflush_page(sg_page_iter_page(&sg_iter)); 138 mb(); /*Make sure that all cache line entry is flushed*/ 139 140 return; 141 } 142 143 if (wbinvd_on_all_cpus()) 144 pr_err("Timed out waiting for cache flush\n"); 145 #else 146 pr_err("Architecture has no drm_cache.c support\n"); 147 WARN_ON_ONCE(1); 148 #endif 149 } 150 EXPORT_SYMBOL(drm_clflush_sg); 151 152 /** 153 * drm_clflush_virt_range - Flush dcache lines of a region 154 * @addr: Initial kernel memory address. 155 * @length: Region size. 156 * 157 * Flush every data cache line entry that points to an address in the 158 * region requested. 159 */ 160 void 161 drm_clflush_virt_range(void *addr, unsigned long length) 162 { 163 #if defined(CONFIG_X86) 164 if (static_cpu_has(X86_FEATURE_CLFLUSH)) { 165 const int size = boot_cpu_data.x86_clflush_size; 166 void *end = addr + length; 167 168 addr = (void *)(((unsigned long)addr) & -size); 169 mb(); /*CLFLUSH is only ordered with a full memory barrier*/ 170 for (; addr < end; addr += size) 171 clflushopt(addr); 172 clflushopt(end - 1); /* force serialisation */ 173 mb(); /*Ensure that every data cache line entry is flushed*/ 174 return; 175 } 176 177 if (wbinvd_on_all_cpus()) 178 pr_err("Timed out waiting for cache flush\n"); 179 #else 180 pr_err("Architecture has no drm_cache.c support\n"); 181 WARN_ON_ONCE(1); 182 #endif 183 } 184 EXPORT_SYMBOL(drm_clflush_virt_range); 185 186 bool drm_need_swiotlb(int dma_bits) 187 { 188 struct resource *tmp; 189 resource_size_t max_iomem = 0; 190 191 /* 192 * Xen paravirtual hosts require swiotlb regardless of requested dma 193 * transfer size. 194 * 195 * NOTE: Really, what it requires is use of the dma_alloc_coherent 196 * allocator used in ttm_dma_populate() instead of 197 * ttm_populate_and_map_pages(), which bounce buffers so much in 198 * Xen it leads to swiotlb buffer exhaustion. 199 */ 200 if (xen_pv_domain()) 201 return true; 202 203 /* 204 * Enforce dma_alloc_coherent when memory encryption is active as well 205 * for the same reasons as for Xen paravirtual hosts. 206 */ 207 if (mem_encrypt_active()) 208 return true; 209 210 for (tmp = iomem_resource.child; tmp; tmp = tmp->sibling) 211 max_iomem = max(max_iomem, tmp->end); 212 213 return max_iomem > ((u64)1 << dma_bits); 214 } 215 EXPORT_SYMBOL(drm_need_swiotlb); 216 217 static void memcpy_fallback(struct dma_buf_map *dst, 218 const struct dma_buf_map *src, 219 unsigned long len) 220 { 221 if (!dst->is_iomem && !src->is_iomem) { 222 memcpy(dst->vaddr, src->vaddr, len); 223 } else if (!src->is_iomem) { 224 dma_buf_map_memcpy_to(dst, src->vaddr, len); 225 } else if (!dst->is_iomem) { 226 memcpy_fromio(dst->vaddr, src->vaddr_iomem, len); 227 } else { 228 /* 229 * Bounce size is not performance tuned, but using a 230 * bounce buffer like this is significantly faster than 231 * resorting to ioreadxx() + iowritexx(). 232 */ 233 char bounce[MEMCPY_BOUNCE_SIZE]; 234 void __iomem *_src = src->vaddr_iomem; 235 void __iomem *_dst = dst->vaddr_iomem; 236 237 while (len >= MEMCPY_BOUNCE_SIZE) { 238 memcpy_fromio(bounce, _src, MEMCPY_BOUNCE_SIZE); 239 memcpy_toio(_dst, bounce, MEMCPY_BOUNCE_SIZE); 240 _src += MEMCPY_BOUNCE_SIZE; 241 _dst += MEMCPY_BOUNCE_SIZE; 242 len -= MEMCPY_BOUNCE_SIZE; 243 } 244 if (len) { 245 memcpy_fromio(bounce, _src, MEMCPY_BOUNCE_SIZE); 246 memcpy_toio(_dst, bounce, MEMCPY_BOUNCE_SIZE); 247 } 248 } 249 } 250 251 #ifdef CONFIG_X86 252 253 static DEFINE_STATIC_KEY_FALSE(has_movntdqa); 254 255 static void __memcpy_ntdqa(void *dst, const void *src, unsigned long len) 256 { 257 kernel_fpu_begin(); 258 259 while (len >= 4) { 260 asm("movntdqa (%0), %%xmm0\n" 261 "movntdqa 16(%0), %%xmm1\n" 262 "movntdqa 32(%0), %%xmm2\n" 263 "movntdqa 48(%0), %%xmm3\n" 264 "movaps %%xmm0, (%1)\n" 265 "movaps %%xmm1, 16(%1)\n" 266 "movaps %%xmm2, 32(%1)\n" 267 "movaps %%xmm3, 48(%1)\n" 268 :: "r" (src), "r" (dst) : "memory"); 269 src += 64; 270 dst += 64; 271 len -= 4; 272 } 273 while (len--) { 274 asm("movntdqa (%0), %%xmm0\n" 275 "movaps %%xmm0, (%1)\n" 276 :: "r" (src), "r" (dst) : "memory"); 277 src += 16; 278 dst += 16; 279 } 280 281 kernel_fpu_end(); 282 } 283 284 /* 285 * __drm_memcpy_from_wc copies @len bytes from @src to @dst using 286 * non-temporal instructions where available. Note that all arguments 287 * (@src, @dst) must be aligned to 16 bytes and @len must be a multiple 288 * of 16. 289 */ 290 static void __drm_memcpy_from_wc(void *dst, const void *src, unsigned long len) 291 { 292 if (unlikely(((unsigned long)dst | (unsigned long)src | len) & 15)) 293 memcpy(dst, src, len); 294 else if (likely(len)) 295 __memcpy_ntdqa(dst, src, len >> 4); 296 } 297 298 /** 299 * drm_memcpy_from_wc - Perform the fastest available memcpy from a source 300 * that may be WC. 301 * @dst: The destination pointer 302 * @src: The source pointer 303 * @len: The size of the area o transfer in bytes 304 * 305 * Tries an arch optimized memcpy for prefetching reading out of a WC region, 306 * and if no such beast is available, falls back to a normal memcpy. 307 */ 308 void drm_memcpy_from_wc(struct dma_buf_map *dst, 309 const struct dma_buf_map *src, 310 unsigned long len) 311 { 312 if (WARN_ON(in_interrupt())) { 313 memcpy_fallback(dst, src, len); 314 return; 315 } 316 317 if (static_branch_likely(&has_movntdqa)) { 318 __drm_memcpy_from_wc(dst->is_iomem ? 319 (void __force *)dst->vaddr_iomem : 320 dst->vaddr, 321 src->is_iomem ? 322 (void const __force *)src->vaddr_iomem : 323 src->vaddr, 324 len); 325 return; 326 } 327 328 memcpy_fallback(dst, src, len); 329 } 330 EXPORT_SYMBOL(drm_memcpy_from_wc); 331 332 /* 333 * drm_memcpy_init_early - One time initialization of the WC memcpy code 334 */ 335 void drm_memcpy_init_early(void) 336 { 337 /* 338 * Some hypervisors (e.g. KVM) don't support VEX-prefix instructions 339 * emulation. So don't enable movntdqa in hypervisor guest. 340 */ 341 if (static_cpu_has(X86_FEATURE_XMM4_1) && 342 !boot_cpu_has(X86_FEATURE_HYPERVISOR)) 343 static_branch_enable(&has_movntdqa); 344 } 345 #else 346 void drm_memcpy_from_wc(struct dma_buf_map *dst, 347 const struct dma_buf_map *src, 348 unsigned long len) 349 { 350 WARN_ON(in_interrupt()); 351 352 memcpy_fallback(dst, src, len); 353 } 354 EXPORT_SYMBOL(drm_memcpy_from_wc); 355 356 void drm_memcpy_init_early(void) 357 { 358 } 359 #endif /* CONFIG_X86 */ 360