1 /* Declare dependencies between CPUIDs */ 2 #include <linux/kernel.h> 3 #include <linux/init.h> 4 #include <linux/module.h> 5 #include <asm/cpufeature.h> 6 7 struct cpuid_dep { 8 unsigned int feature; 9 unsigned int depends; 10 }; 11 12 /* 13 * Table of CPUID features that depend on others. 14 * 15 * This only includes dependencies that can be usefully disabled, not 16 * features part of the base set (like FPU). 17 * 18 * Note this all is not __init / __initdata because it can be 19 * called from cpu hotplug. It shouldn't do anything in this case, 20 * but it's difficult to tell that to the init reference checker. 21 */ 22 static const struct cpuid_dep cpuid_deps[] = { 23 { X86_FEATURE_XSAVEOPT, X86_FEATURE_XSAVE }, 24 { X86_FEATURE_XSAVEC, X86_FEATURE_XSAVE }, 25 { X86_FEATURE_XSAVES, X86_FEATURE_XSAVE }, 26 { X86_FEATURE_AVX, X86_FEATURE_XSAVE }, 27 { X86_FEATURE_PKU, X86_FEATURE_XSAVE }, 28 { X86_FEATURE_MPX, X86_FEATURE_XSAVE }, 29 { X86_FEATURE_XGETBV1, X86_FEATURE_XSAVE }, 30 { X86_FEATURE_FXSR_OPT, X86_FEATURE_FXSR }, 31 { X86_FEATURE_XMM, X86_FEATURE_FXSR }, 32 { X86_FEATURE_XMM2, X86_FEATURE_XMM }, 33 { X86_FEATURE_XMM3, X86_FEATURE_XMM2 }, 34 { X86_FEATURE_XMM4_1, X86_FEATURE_XMM2 }, 35 { X86_FEATURE_XMM4_2, X86_FEATURE_XMM2 }, 36 { X86_FEATURE_XMM3, X86_FEATURE_XMM2 }, 37 { X86_FEATURE_PCLMULQDQ, X86_FEATURE_XMM2 }, 38 { X86_FEATURE_SSSE3, X86_FEATURE_XMM2, }, 39 { X86_FEATURE_F16C, X86_FEATURE_XMM2, }, 40 { X86_FEATURE_AES, X86_FEATURE_XMM2 }, 41 { X86_FEATURE_SHA_NI, X86_FEATURE_XMM2 }, 42 { X86_FEATURE_FMA, X86_FEATURE_AVX }, 43 { X86_FEATURE_AVX2, X86_FEATURE_AVX, }, 44 { X86_FEATURE_AVX512F, X86_FEATURE_AVX, }, 45 { X86_FEATURE_AVX512IFMA, X86_FEATURE_AVX512F }, 46 { X86_FEATURE_AVX512PF, X86_FEATURE_AVX512F }, 47 { X86_FEATURE_AVX512ER, X86_FEATURE_AVX512F }, 48 { X86_FEATURE_AVX512CD, X86_FEATURE_AVX512F }, 49 { X86_FEATURE_AVX512DQ, X86_FEATURE_AVX512F }, 50 { X86_FEATURE_AVX512BW, X86_FEATURE_AVX512F }, 51 { X86_FEATURE_AVX512VL, X86_FEATURE_AVX512F }, 52 { X86_FEATURE_AVX512VBMI, X86_FEATURE_AVX512F }, 53 { X86_FEATURE_AVX512_VBMI2, X86_FEATURE_AVX512VL }, 54 { X86_FEATURE_GFNI, X86_FEATURE_AVX512VL }, 55 { X86_FEATURE_VAES, X86_FEATURE_AVX512VL }, 56 { X86_FEATURE_VPCLMULQDQ, X86_FEATURE_AVX512VL }, 57 { X86_FEATURE_AVX512_VNNI, X86_FEATURE_AVX512VL }, 58 { X86_FEATURE_AVX512_BITALG, X86_FEATURE_AVX512VL }, 59 { X86_FEATURE_AVX512_4VNNIW, X86_FEATURE_AVX512F }, 60 { X86_FEATURE_AVX512_4FMAPS, X86_FEATURE_AVX512F }, 61 { X86_FEATURE_AVX512_VPOPCNTDQ, X86_FEATURE_AVX512F }, 62 {} 63 }; 64 65 static inline void clear_feature(struct cpuinfo_x86 *c, unsigned int feature) 66 { 67 /* 68 * Note: This could use the non atomic __*_bit() variants, but the 69 * rest of the cpufeature code uses atomics as well, so keep it for 70 * consistency. Cleanup all of it separately. 71 */ 72 if (!c) { 73 clear_cpu_cap(&boot_cpu_data, feature); 74 set_bit(feature, (unsigned long *)cpu_caps_cleared); 75 } else { 76 clear_bit(feature, (unsigned long *)c->x86_capability); 77 } 78 } 79 80 /* Take the capabilities and the BUG bits into account */ 81 #define MAX_FEATURE_BITS ((NCAPINTS + NBUGINTS) * sizeof(u32) * 8) 82 83 static void do_clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int feature) 84 { 85 DECLARE_BITMAP(disable, MAX_FEATURE_BITS); 86 const struct cpuid_dep *d; 87 bool changed; 88 89 if (WARN_ON(feature >= MAX_FEATURE_BITS)) 90 return; 91 92 clear_feature(c, feature); 93 94 /* Collect all features to disable, handling dependencies */ 95 memset(disable, 0, sizeof(disable)); 96 __set_bit(feature, disable); 97 98 /* Loop until we get a stable state. */ 99 do { 100 changed = false; 101 for (d = cpuid_deps; d->feature; d++) { 102 if (!test_bit(d->depends, disable)) 103 continue; 104 if (__test_and_set_bit(d->feature, disable)) 105 continue; 106 107 changed = true; 108 clear_feature(c, d->feature); 109 } 110 } while (changed); 111 } 112 113 void clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int feature) 114 { 115 do_clear_cpu_cap(c, feature); 116 } 117 118 void setup_clear_cpu_cap(unsigned int feature) 119 { 120 do_clear_cpu_cap(NULL, feature); 121 } 122