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 <asm/fpu/api.h> 27 28 #include "i915_memcpy.h" 29 30 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG) 31 #define CI_BUG_ON(expr) BUG_ON(expr) 32 #else 33 #define CI_BUG_ON(expr) BUILD_BUG_ON_INVALID(expr) 34 #endif 35 36 static DEFINE_STATIC_KEY_FALSE(has_movntdqa); 37 38 static void __memcpy_ntdqa(void *dst, const void *src, unsigned long len) 39 { 40 kernel_fpu_begin(); 41 42 while (len >= 4) { 43 asm("movntdqa (%0), %%xmm0\n" 44 "movntdqa 16(%0), %%xmm1\n" 45 "movntdqa 32(%0), %%xmm2\n" 46 "movntdqa 48(%0), %%xmm3\n" 47 "movaps %%xmm0, (%1)\n" 48 "movaps %%xmm1, 16(%1)\n" 49 "movaps %%xmm2, 32(%1)\n" 50 "movaps %%xmm3, 48(%1)\n" 51 :: "r" (src), "r" (dst) : "memory"); 52 src += 64; 53 dst += 64; 54 len -= 4; 55 } 56 while (len--) { 57 asm("movntdqa (%0), %%xmm0\n" 58 "movaps %%xmm0, (%1)\n" 59 :: "r" (src), "r" (dst) : "memory"); 60 src += 16; 61 dst += 16; 62 } 63 64 kernel_fpu_end(); 65 } 66 67 static void __memcpy_ntdqu(void *dst, const void *src, unsigned long len) 68 { 69 kernel_fpu_begin(); 70 71 while (len >= 4) { 72 asm("movntdqa (%0), %%xmm0\n" 73 "movntdqa 16(%0), %%xmm1\n" 74 "movntdqa 32(%0), %%xmm2\n" 75 "movntdqa 48(%0), %%xmm3\n" 76 "movups %%xmm0, (%1)\n" 77 "movups %%xmm1, 16(%1)\n" 78 "movups %%xmm2, 32(%1)\n" 79 "movups %%xmm3, 48(%1)\n" 80 :: "r" (src), "r" (dst) : "memory"); 81 src += 64; 82 dst += 64; 83 len -= 4; 84 } 85 while (len--) { 86 asm("movntdqa (%0), %%xmm0\n" 87 "movups %%xmm0, (%1)\n" 88 :: "r" (src), "r" (dst) : "memory"); 89 src += 16; 90 dst += 16; 91 } 92 93 kernel_fpu_end(); 94 } 95 96 /** 97 * i915_memcpy_from_wc: perform an accelerated *aligned* read from WC 98 * @dst: destination pointer 99 * @src: source pointer 100 * @len: how many bytes to copy 101 * 102 * i915_memcpy_from_wc copies @len bytes from @src to @dst using 103 * non-temporal instructions where available. Note that all arguments 104 * (@src, @dst) must be aligned to 16 bytes and @len must be a multiple 105 * of 16. 106 * 107 * To test whether accelerated reads from WC are supported, use 108 * i915_memcpy_from_wc(NULL, NULL, 0); 109 * 110 * Returns true if the copy was successful, false if the preconditions 111 * are not met. 112 */ 113 bool i915_memcpy_from_wc(void *dst, const void *src, unsigned long len) 114 { 115 if (unlikely(((unsigned long)dst | (unsigned long)src | len) & 15)) 116 return false; 117 118 if (static_branch_likely(&has_movntdqa)) { 119 if (likely(len)) 120 __memcpy_ntdqa(dst, src, len >> 4); 121 return true; 122 } 123 124 return false; 125 } 126 127 /** 128 * i915_unaligned_memcpy_from_wc: perform a mostly accelerated read from WC 129 * @dst: destination pointer 130 * @src: source pointer 131 * @len: how many bytes to copy 132 * 133 * Like i915_memcpy_from_wc(), the unaligned variant copies @len bytes from 134 * @src to @dst using * non-temporal instructions where available, but 135 * accepts that its arguments may not be aligned, but are valid for the 136 * potential 16-byte read past the end. 137 */ 138 void i915_unaligned_memcpy_from_wc(void *dst, void *src, unsigned long len) 139 { 140 unsigned long addr; 141 142 CI_BUG_ON(!i915_has_memcpy_from_wc()); 143 144 addr = (unsigned long)src; 145 if (!IS_ALIGNED(addr, 16)) { 146 unsigned long x = min(ALIGN(addr, 16) - addr, len); 147 148 memcpy(dst, src, x); 149 150 len -= x; 151 dst += x; 152 src += x; 153 } 154 155 if (likely(len)) 156 __memcpy_ntdqu(dst, src, DIV_ROUND_UP(len, 16)); 157 } 158 159 void i915_memcpy_init_early(struct drm_i915_private *dev_priv) 160 { 161 /* 162 * Some hypervisors (e.g. KVM) don't support VEX-prefix instructions 163 * emulation. So don't enable movntdqa in hypervisor guest. 164 */ 165 if (static_cpu_has(X86_FEATURE_XMM4_1) && 166 !boot_cpu_has(X86_FEATURE_HYPERVISOR)) 167 static_branch_enable(&has_movntdqa); 168 } 169