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 #include <linux/cc_platform.h> 31 #include <linux/export.h> 32 #include <linux/highmem.h> 33 #include <linux/ioport.h> 34 #include <linux/iosys-map.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 wbinvd_on_all_cpus(); 97 98 #elif defined(__powerpc__) 99 unsigned long i; 100 101 for (i = 0; i < num_pages; i++) { 102 struct page *page = pages[i]; 103 void *page_virtual; 104 105 if (unlikely(page == NULL)) 106 continue; 107 108 page_virtual = kmap_atomic(page); 109 flush_dcache_range((unsigned long)page_virtual, 110 (unsigned long)page_virtual + PAGE_SIZE); 111 kunmap_atomic(page_virtual); 112 } 113 #else 114 WARN_ONCE(1, "Architecture has no drm_cache.c support\n"); 115 #endif 116 } 117 EXPORT_SYMBOL(drm_clflush_pages); 118 119 /** 120 * drm_clflush_sg - Flush dcache lines pointing to a scather-gather. 121 * @st: struct sg_table. 122 * 123 * Flush every data cache line entry that points to an address in the 124 * sg. 125 */ 126 void 127 drm_clflush_sg(struct sg_table *st) 128 { 129 #if defined(CONFIG_X86) 130 if (static_cpu_has(X86_FEATURE_CLFLUSH)) { 131 struct sg_page_iter sg_iter; 132 133 mb(); /*CLFLUSH is ordered only by using memory barriers*/ 134 for_each_sgtable_page(st, &sg_iter, 0) 135 drm_clflush_page(sg_page_iter_page(&sg_iter)); 136 mb(); /*Make sure that all cache line entry is flushed*/ 137 138 return; 139 } 140 141 wbinvd_on_all_cpus(); 142 #else 143 WARN_ONCE(1, "Architecture has no drm_cache.c support\n"); 144 #endif 145 } 146 EXPORT_SYMBOL(drm_clflush_sg); 147 148 /** 149 * drm_clflush_virt_range - Flush dcache lines of a region 150 * @addr: Initial kernel memory address. 151 * @length: Region size. 152 * 153 * Flush every data cache line entry that points to an address in the 154 * region requested. 155 */ 156 void 157 drm_clflush_virt_range(void *addr, unsigned long length) 158 { 159 #if defined(CONFIG_X86) 160 if (static_cpu_has(X86_FEATURE_CLFLUSH)) { 161 const int size = boot_cpu_data.x86_clflush_size; 162 void *end = addr + length; 163 164 addr = (void *)(((unsigned long)addr) & -size); 165 mb(); /*CLFLUSH is only ordered with a full memory barrier*/ 166 for (; addr < end; addr += size) 167 clflushopt(addr); 168 clflushopt(end - 1); /* force serialisation */ 169 mb(); /*Ensure that every data cache line entry is flushed*/ 170 return; 171 } 172 173 wbinvd_on_all_cpus(); 174 #else 175 WARN_ONCE(1, "Architecture has no drm_cache.c support\n"); 176 #endif 177 } 178 EXPORT_SYMBOL(drm_clflush_virt_range); 179 180 bool drm_need_swiotlb(int dma_bits) 181 { 182 struct resource *tmp; 183 resource_size_t max_iomem = 0; 184 185 /* 186 * Xen paravirtual hosts require swiotlb regardless of requested dma 187 * transfer size. 188 * 189 * NOTE: Really, what it requires is use of the dma_alloc_coherent 190 * allocator used in ttm_dma_populate() instead of 191 * ttm_populate_and_map_pages(), which bounce buffers so much in 192 * Xen it leads to swiotlb buffer exhaustion. 193 */ 194 if (xen_pv_domain()) 195 return true; 196 197 /* 198 * Enforce dma_alloc_coherent when memory encryption is active as well 199 * for the same reasons as for Xen paravirtual hosts. 200 */ 201 if (cc_platform_has(CC_ATTR_MEM_ENCRYPT)) 202 return true; 203 204 for (tmp = iomem_resource.child; tmp; tmp = tmp->sibling) 205 max_iomem = max(max_iomem, tmp->end); 206 207 return max_iomem > ((u64)1 << dma_bits); 208 } 209 EXPORT_SYMBOL(drm_need_swiotlb); 210 211 static void memcpy_fallback(struct iosys_map *dst, 212 const struct iosys_map *src, 213 unsigned long len) 214 { 215 if (!dst->is_iomem && !src->is_iomem) { 216 memcpy(dst->vaddr, src->vaddr, len); 217 } else if (!src->is_iomem) { 218 iosys_map_memcpy_to(dst, 0, src->vaddr, len); 219 } else if (!dst->is_iomem) { 220 memcpy_fromio(dst->vaddr, src->vaddr_iomem, len); 221 } else { 222 /* 223 * Bounce size is not performance tuned, but using a 224 * bounce buffer like this is significantly faster than 225 * resorting to ioreadxx() + iowritexx(). 226 */ 227 char bounce[MEMCPY_BOUNCE_SIZE]; 228 void __iomem *_src = src->vaddr_iomem; 229 void __iomem *_dst = dst->vaddr_iomem; 230 231 while (len >= MEMCPY_BOUNCE_SIZE) { 232 memcpy_fromio(bounce, _src, MEMCPY_BOUNCE_SIZE); 233 memcpy_toio(_dst, bounce, MEMCPY_BOUNCE_SIZE); 234 _src += MEMCPY_BOUNCE_SIZE; 235 _dst += MEMCPY_BOUNCE_SIZE; 236 len -= MEMCPY_BOUNCE_SIZE; 237 } 238 if (len) { 239 memcpy_fromio(bounce, _src, MEMCPY_BOUNCE_SIZE); 240 memcpy_toio(_dst, bounce, MEMCPY_BOUNCE_SIZE); 241 } 242 } 243 } 244 245 #ifdef CONFIG_X86 246 247 static DEFINE_STATIC_KEY_FALSE(has_movntdqa); 248 249 static void __memcpy_ntdqa(void *dst, const void *src, unsigned long len) 250 { 251 kernel_fpu_begin(); 252 253 while (len >= 4) { 254 asm("movntdqa (%0), %%xmm0\n" 255 "movntdqa 16(%0), %%xmm1\n" 256 "movntdqa 32(%0), %%xmm2\n" 257 "movntdqa 48(%0), %%xmm3\n" 258 "movaps %%xmm0, (%1)\n" 259 "movaps %%xmm1, 16(%1)\n" 260 "movaps %%xmm2, 32(%1)\n" 261 "movaps %%xmm3, 48(%1)\n" 262 :: "r" (src), "r" (dst) : "memory"); 263 src += 64; 264 dst += 64; 265 len -= 4; 266 } 267 while (len--) { 268 asm("movntdqa (%0), %%xmm0\n" 269 "movaps %%xmm0, (%1)\n" 270 :: "r" (src), "r" (dst) : "memory"); 271 src += 16; 272 dst += 16; 273 } 274 275 kernel_fpu_end(); 276 } 277 278 /* 279 * __drm_memcpy_from_wc copies @len bytes from @src to @dst using 280 * non-temporal instructions where available. Note that all arguments 281 * (@src, @dst) must be aligned to 16 bytes and @len must be a multiple 282 * of 16. 283 */ 284 static void __drm_memcpy_from_wc(void *dst, const void *src, unsigned long len) 285 { 286 if (unlikely(((unsigned long)dst | (unsigned long)src | len) & 15)) 287 memcpy(dst, src, len); 288 else if (likely(len)) 289 __memcpy_ntdqa(dst, src, len >> 4); 290 } 291 292 /** 293 * drm_memcpy_from_wc - Perform the fastest available memcpy from a source 294 * that may be WC. 295 * @dst: The destination pointer 296 * @src: The source pointer 297 * @len: The size of the area o transfer in bytes 298 * 299 * Tries an arch optimized memcpy for prefetching reading out of a WC region, 300 * and if no such beast is available, falls back to a normal memcpy. 301 */ 302 void drm_memcpy_from_wc(struct iosys_map *dst, 303 const struct iosys_map *src, 304 unsigned long len) 305 { 306 if (WARN_ON(in_interrupt())) { 307 memcpy_fallback(dst, src, len); 308 return; 309 } 310 311 if (static_branch_likely(&has_movntdqa)) { 312 __drm_memcpy_from_wc(dst->is_iomem ? 313 (void __force *)dst->vaddr_iomem : 314 dst->vaddr, 315 src->is_iomem ? 316 (void const __force *)src->vaddr_iomem : 317 src->vaddr, 318 len); 319 return; 320 } 321 322 memcpy_fallback(dst, src, len); 323 } 324 EXPORT_SYMBOL(drm_memcpy_from_wc); 325 326 /* 327 * drm_memcpy_init_early - One time initialization of the WC memcpy code 328 */ 329 void drm_memcpy_init_early(void) 330 { 331 /* 332 * Some hypervisors (e.g. KVM) don't support VEX-prefix instructions 333 * emulation. So don't enable movntdqa in hypervisor guest. 334 */ 335 if (static_cpu_has(X86_FEATURE_XMM4_1) && 336 !boot_cpu_has(X86_FEATURE_HYPERVISOR)) 337 static_branch_enable(&has_movntdqa); 338 } 339 #else 340 void drm_memcpy_from_wc(struct iosys_map *dst, 341 const struct iosys_map *src, 342 unsigned long len) 343 { 344 WARN_ON(in_interrupt()); 345 346 memcpy_fallback(dst, src, len); 347 } 348 EXPORT_SYMBOL(drm_memcpy_from_wc); 349 350 void drm_memcpy_init_early(void) 351 { 352 } 353 #endif /* CONFIG_X86 */ 354