projects/linux·blob uaccess-cleanups · refs

353 lines · 9.5 KiB

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 */
50static void
51drm_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
66static 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 */
86void
87drm_clflush_pages(struct page *pages[], unsigned long num_pages)
88{
89
90#if defined(CONFIG_X86)
91 if (cpu_feature_enabled(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}
117EXPORT_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 */
126void
127drm_clflush_sg(struct sg_table *st)
128{
129#if defined(CONFIG_X86)
130 if (cpu_feature_enabled(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}
146EXPORT_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 */
156void
157drm_clflush_virt_range(void *addr, unsigned long length)
158{
159#if defined(CONFIG_X86)
160 if (cpu_feature_enabled(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}
178EXPORT_SYMBOL(drm_clflush_virt_range);
179
180bool 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}
209EXPORT_SYMBOL(drm_need_swiotlb);
210
211static 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
247static DEFINE_STATIC_KEY_FALSE(has_movntdqa);
248
249static 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 */
284static 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 */
302void 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}
324EXPORT_SYMBOL(drm_memcpy_from_wc);
325
326/*
327 * drm_memcpy_init_early - One time initialization of the WC memcpy code
328 */
329void 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 (cpu_feature_enabled(X86_FEATURE_XMM4_1) &&
336 !boot_cpu_has(X86_FEATURE_HYPERVISOR))
337 static_branch_enable(&has_movntdqa);
338}
339#else
340void 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}
348EXPORT_SYMBOL(drm_memcpy_from_wc);
349
350void drm_memcpy_init_early(void)
351{
352}
353#endif /* CONFIG_X86 */