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 <asm/fpu/api.h> 29 30 #include "i915_memcpy.h" 31 32 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG) 33 #define CI_BUG_ON(expr) BUG_ON(expr) 34 #else 35 #define CI_BUG_ON(expr) BUILD_BUG_ON_INVALID(expr) 36 #endif 37 38 static DEFINE_STATIC_KEY_FALSE(has_movntdqa); 39 40 static void __memcpy_ntdqa(void *dst, const void *src, unsigned long len) 41 { 42 kernel_fpu_begin(); 43 44 while (len >= 4) { 45 asm("movntdqa (%0), %%xmm0\n" 46 "movntdqa 16(%0), %%xmm1\n" 47 "movntdqa 32(%0), %%xmm2\n" 48 "movntdqa 48(%0), %%xmm3\n" 49 "movaps %%xmm0, (%1)\n" 50 "movaps %%xmm1, 16(%1)\n" 51 "movaps %%xmm2, 32(%1)\n" 52 "movaps %%xmm3, 48(%1)\n" 53 :: "r" (src), "r" (dst) : "memory"); 54 src += 64; 55 dst += 64; 56 len -= 4; 57 } 58 while (len--) { 59 asm("movntdqa (%0), %%xmm0\n" 60 "movaps %%xmm0, (%1)\n" 61 :: "r" (src), "r" (dst) : "memory"); 62 src += 16; 63 dst += 16; 64 } 65 66 kernel_fpu_end(); 67 } 68 69 static void __memcpy_ntdqu(void *dst, const void *src, unsigned long len) 70 { 71 kernel_fpu_begin(); 72 73 while (len >= 4) { 74 asm("movntdqa (%0), %%xmm0\n" 75 "movntdqa 16(%0), %%xmm1\n" 76 "movntdqa 32(%0), %%xmm2\n" 77 "movntdqa 48(%0), %%xmm3\n" 78 "movups %%xmm0, (%1)\n" 79 "movups %%xmm1, 16(%1)\n" 80 "movups %%xmm2, 32(%1)\n" 81 "movups %%xmm3, 48(%1)\n" 82 :: "r" (src), "r" (dst) : "memory"); 83 src += 64; 84 dst += 64; 85 len -= 4; 86 } 87 while (len--) { 88 asm("movntdqa (%0), %%xmm0\n" 89 "movups %%xmm0, (%1)\n" 90 :: "r" (src), "r" (dst) : "memory"); 91 src += 16; 92 dst += 16; 93 } 94 95 kernel_fpu_end(); 96 } 97 98 /** 99 * i915_memcpy_from_wc: perform an accelerated *aligned* read from WC 100 * @dst: destination pointer 101 * @src: source pointer 102 * @len: how many bytes to copy 103 * 104 * i915_memcpy_from_wc copies @len bytes from @src to @dst using 105 * non-temporal instructions where available. Note that all arguments 106 * (@src, @dst) must be aligned to 16 bytes and @len must be a multiple 107 * of 16. 108 * 109 * To test whether accelerated reads from WC are supported, use 110 * i915_memcpy_from_wc(NULL, NULL, 0); 111 * 112 * Returns true if the copy was successful, false if the preconditions 113 * are not met. 114 */ 115 bool i915_memcpy_from_wc(void *dst, const void *src, unsigned long len) 116 { 117 if (unlikely(((unsigned long)dst | (unsigned long)src | len) & 15)) 118 return false; 119 120 if (static_branch_likely(&has_movntdqa)) { 121 if (likely(len)) 122 __memcpy_ntdqa(dst, src, len >> 4); 123 return true; 124 } 125 126 return false; 127 } 128 129 /** 130 * i915_unaligned_memcpy_from_wc: perform a mostly accelerated read from WC 131 * @dst: destination pointer 132 * @src: source pointer 133 * @len: how many bytes to copy 134 * 135 * Like i915_memcpy_from_wc(), the unaligned variant copies @len bytes from 136 * @src to @dst using * non-temporal instructions where available, but 137 * accepts that its arguments may not be aligned, but are valid for the 138 * potential 16-byte read past the end. 139 */ 140 void i915_unaligned_memcpy_from_wc(void *dst, const void *src, unsigned long len) 141 { 142 unsigned long addr; 143 144 CI_BUG_ON(!i915_has_memcpy_from_wc()); 145 146 addr = (unsigned long)src; 147 if (!IS_ALIGNED(addr, 16)) { 148 unsigned long x = min(ALIGN(addr, 16) - addr, len); 149 150 memcpy(dst, src, x); 151 152 len -= x; 153 dst += x; 154 src += x; 155 } 156 157 if (likely(len)) 158 __memcpy_ntdqu(dst, src, DIV_ROUND_UP(len, 16)); 159 } 160 161 void i915_memcpy_init_early(struct drm_i915_private *dev_priv) 162 { 163 /* 164 * Some hypervisors (e.g. KVM) don't support VEX-prefix instructions 165 * emulation. So don't enable movntdqa in hypervisor guest. 166 */ 167 if (static_cpu_has(X86_FEATURE_XMM4_1) && 168 !boot_cpu_has(X86_FEATURE_HYPERVISOR)) 169 static_branch_enable(&has_movntdqa); 170 } 171