1 /* 2 * Copyright © 2016 Intel Corporation 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a 5 * copy of this software and associated documentation files (the "Software"), 6 * to deal in the Software without restriction, including without limitation 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 8 * and/or sell copies of the Software, and to permit persons to whom the 9 * Software is furnished to do so, subject to the following conditions: 10 * 11 * The above copyright notice and this permission notice (including the next 12 * paragraph) shall be included in all copies or substantial portions of the 13 * Software. 14 * 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 21 * IN THE SOFTWARE. 22 * 23 */ 24 25 #include <linux/kernel.h> 26 #include <linux/string.h> 27 #include <linux/cpufeature.h> 28 #include <linux/bug.h> 29 #include <linux/build_bug.h> 30 #include <asm/fpu/api.h> 31 32 #include "i915_memcpy.h" 33 34 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG) 35 #define CI_BUG_ON(expr) BUG_ON(expr) 36 #else 37 #define CI_BUG_ON(expr) BUILD_BUG_ON_INVALID(expr) 38 #endif 39 40 static DEFINE_STATIC_KEY_FALSE(has_movntdqa); 41 42 static void __memcpy_ntdqa(void *dst, const void *src, unsigned long len) 43 { 44 kernel_fpu_begin(); 45 46 while (len >= 4) { 47 asm("movntdqa (%0), %%xmm0\n" 48 "movntdqa 16(%0), %%xmm1\n" 49 "movntdqa 32(%0), %%xmm2\n" 50 "movntdqa 48(%0), %%xmm3\n" 51 "movaps %%xmm0, (%1)\n" 52 "movaps %%xmm1, 16(%1)\n" 53 "movaps %%xmm2, 32(%1)\n" 54 "movaps %%xmm3, 48(%1)\n" 55 :: "r" (src), "r" (dst) : "memory"); 56 src += 64; 57 dst += 64; 58 len -= 4; 59 } 60 while (len--) { 61 asm("movntdqa (%0), %%xmm0\n" 62 "movaps %%xmm0, (%1)\n" 63 :: "r" (src), "r" (dst) : "memory"); 64 src += 16; 65 dst += 16; 66 } 67 68 kernel_fpu_end(); 69 } 70 71 static void __memcpy_ntdqu(void *dst, const void *src, unsigned long len) 72 { 73 kernel_fpu_begin(); 74 75 while (len >= 4) { 76 asm("movntdqa (%0), %%xmm0\n" 77 "movntdqa 16(%0), %%xmm1\n" 78 "movntdqa 32(%0), %%xmm2\n" 79 "movntdqa 48(%0), %%xmm3\n" 80 "movups %%xmm0, (%1)\n" 81 "movups %%xmm1, 16(%1)\n" 82 "movups %%xmm2, 32(%1)\n" 83 "movups %%xmm3, 48(%1)\n" 84 :: "r" (src), "r" (dst) : "memory"); 85 src += 64; 86 dst += 64; 87 len -= 4; 88 } 89 while (len--) { 90 asm("movntdqa (%0), %%xmm0\n" 91 "movups %%xmm0, (%1)\n" 92 :: "r" (src), "r" (dst) : "memory"); 93 src += 16; 94 dst += 16; 95 } 96 97 kernel_fpu_end(); 98 } 99 100 /** 101 * i915_memcpy_from_wc: perform an accelerated *aligned* read from WC 102 * @dst: destination pointer 103 * @src: source pointer 104 * @len: how many bytes to copy 105 * 106 * i915_memcpy_from_wc copies @len bytes from @src to @dst using 107 * non-temporal instructions where available. Note that all arguments 108 * (@src, @dst) must be aligned to 16 bytes and @len must be a multiple 109 * of 16. 110 * 111 * To test whether accelerated reads from WC are supported, use 112 * i915_memcpy_from_wc(NULL, NULL, 0); 113 * 114 * Returns true if the copy was successful, false if the preconditions 115 * are not met. 116 */ 117 bool i915_memcpy_from_wc(void *dst, const void *src, unsigned long len) 118 { 119 if (unlikely(((unsigned long)dst | (unsigned long)src | len) & 15)) 120 return false; 121 122 if (static_branch_likely(&has_movntdqa)) { 123 if (likely(len)) 124 __memcpy_ntdqa(dst, src, len >> 4); 125 return true; 126 } 127 128 return false; 129 } 130 131 /** 132 * i915_unaligned_memcpy_from_wc: perform a mostly accelerated read from WC 133 * @dst: destination pointer 134 * @src: source pointer 135 * @len: how many bytes to copy 136 * 137 * Like i915_memcpy_from_wc(), the unaligned variant copies @len bytes from 138 * @src to @dst using * non-temporal instructions where available, but 139 * accepts that its arguments may not be aligned, but are valid for the 140 * potential 16-byte read past the end. 141 */ 142 void i915_unaligned_memcpy_from_wc(void *dst, const void *src, unsigned long len) 143 { 144 unsigned long addr; 145 146 CI_BUG_ON(!i915_has_memcpy_from_wc()); 147 148 addr = (unsigned long)src; 149 if (!IS_ALIGNED(addr, 16)) { 150 unsigned long x = min(ALIGN(addr, 16) - addr, len); 151 152 memcpy(dst, src, x); 153 154 len -= x; 155 dst += x; 156 src += x; 157 } 158 159 if (likely(len)) 160 __memcpy_ntdqu(dst, src, DIV_ROUND_UP(len, 16)); 161 } 162 163 void i915_memcpy_init_early(struct drm_i915_private *dev_priv) 164 { 165 /* 166 * Some hypervisors (e.g. KVM) don't support VEX-prefix instructions 167 * emulation. So don't enable movntdqa in hypervisor guest. 168 */ 169 if (static_cpu_has(X86_FEATURE_XMM4_1) && 170 !boot_cpu_has(X86_FEATURE_HYPERVISOR)) 171 static_branch_enable(&has_movntdqa); 172 } 173