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_FXSR, X86_FEATURE_FPU }, 24 { X86_FEATURE_XSAVEOPT, X86_FEATURE_XSAVE }, 25 { X86_FEATURE_XSAVEC, X86_FEATURE_XSAVE }, 26 { X86_FEATURE_XSAVES, X86_FEATURE_XSAVE }, 27 { X86_FEATURE_AVX, X86_FEATURE_XSAVE }, 28 { X86_FEATURE_PKU, X86_FEATURE_XSAVE }, 29 { X86_FEATURE_MPX, X86_FEATURE_XSAVE }, 30 { X86_FEATURE_XGETBV1, X86_FEATURE_XSAVE }, 31 { X86_FEATURE_APX, X86_FEATURE_XSAVE }, 32 { X86_FEATURE_CMOV, X86_FEATURE_FXSR }, 33 { X86_FEATURE_MMX, X86_FEATURE_FXSR }, 34 { X86_FEATURE_MMXEXT, X86_FEATURE_MMX }, 35 { X86_FEATURE_FXSR_OPT, X86_FEATURE_FXSR }, 36 { X86_FEATURE_XSAVE, X86_FEATURE_FXSR }, 37 { X86_FEATURE_XMM, X86_FEATURE_FXSR }, 38 { X86_FEATURE_XMM2, X86_FEATURE_XMM }, 39 { X86_FEATURE_XMM3, X86_FEATURE_XMM2 }, 40 { X86_FEATURE_XMM4_1, X86_FEATURE_XMM2 }, 41 { X86_FEATURE_XMM4_2, X86_FEATURE_XMM2 }, 42 { X86_FEATURE_XMM3, X86_FEATURE_XMM2 }, 43 { X86_FEATURE_PCLMULQDQ, X86_FEATURE_XMM2 }, 44 { X86_FEATURE_SSSE3, X86_FEATURE_XMM2, }, 45 { X86_FEATURE_F16C, X86_FEATURE_XMM2, }, 46 { X86_FEATURE_AES, X86_FEATURE_XMM2 }, 47 { X86_FEATURE_SHA_NI, X86_FEATURE_XMM2 }, 48 { X86_FEATURE_GFNI, X86_FEATURE_XMM2 }, 49 { X86_FEATURE_AVX_VNNI, X86_FEATURE_AVX }, 50 { X86_FEATURE_FMA, X86_FEATURE_AVX }, 51 { X86_FEATURE_VAES, X86_FEATURE_AVX }, 52 { X86_FEATURE_VPCLMULQDQ, X86_FEATURE_AVX }, 53 { X86_FEATURE_AVX2, X86_FEATURE_AVX, }, 54 { X86_FEATURE_AVX512F, X86_FEATURE_AVX, }, 55 { X86_FEATURE_AVX512IFMA, X86_FEATURE_AVX512F }, 56 { X86_FEATURE_AVX512PF, X86_FEATURE_AVX512F }, 57 { X86_FEATURE_AVX512ER, X86_FEATURE_AVX512F }, 58 { X86_FEATURE_AVX512CD, X86_FEATURE_AVX512F }, 59 { X86_FEATURE_AVX512DQ, X86_FEATURE_AVX512F }, 60 { X86_FEATURE_AVX512BW, X86_FEATURE_AVX512F }, 61 { X86_FEATURE_AVX512VL, X86_FEATURE_AVX512F }, 62 { X86_FEATURE_AVX512VBMI, X86_FEATURE_AVX512F }, 63 { X86_FEATURE_AVX512_VBMI2, X86_FEATURE_AVX512VL }, 64 { X86_FEATURE_AVX512_VNNI, X86_FEATURE_AVX512VL }, 65 { X86_FEATURE_AVX512_BITALG, X86_FEATURE_AVX512VL }, 66 { X86_FEATURE_AVX512_4VNNIW, X86_FEATURE_AVX512F }, 67 { X86_FEATURE_AVX512_4FMAPS, X86_FEATURE_AVX512F }, 68 { X86_FEATURE_AVX512_VPOPCNTDQ, X86_FEATURE_AVX512F }, 69 { X86_FEATURE_AVX512_VP2INTERSECT, X86_FEATURE_AVX512VL }, 70 { X86_FEATURE_CQM_OCCUP_LLC, X86_FEATURE_CQM_LLC }, 71 { X86_FEATURE_CQM_MBM_TOTAL, X86_FEATURE_CQM_LLC }, 72 { X86_FEATURE_CQM_MBM_LOCAL, X86_FEATURE_CQM_LLC }, 73 { X86_FEATURE_BMEC, X86_FEATURE_CQM_MBM_TOTAL }, 74 { X86_FEATURE_BMEC, X86_FEATURE_CQM_MBM_LOCAL }, 75 { X86_FEATURE_AVX512_BF16, X86_FEATURE_AVX512VL }, 76 { X86_FEATURE_AVX512_FP16, X86_FEATURE_AVX512BW }, 77 { X86_FEATURE_ENQCMD, X86_FEATURE_XSAVES }, 78 { X86_FEATURE_PER_THREAD_MBA, X86_FEATURE_MBA }, 79 { X86_FEATURE_SGX_LC, X86_FEATURE_SGX }, 80 { X86_FEATURE_SGX1, X86_FEATURE_SGX }, 81 { X86_FEATURE_SGX2, X86_FEATURE_SGX1 }, 82 { X86_FEATURE_SGX_EDECCSSA, X86_FEATURE_SGX1 }, 83 { X86_FEATURE_XFD, X86_FEATURE_XSAVES }, 84 { X86_FEATURE_XFD, X86_FEATURE_XGETBV1 }, 85 { X86_FEATURE_AMX_TILE, X86_FEATURE_XFD }, 86 { X86_FEATURE_AMX_FP16, X86_FEATURE_AMX_TILE }, 87 { X86_FEATURE_AMX_BF16, X86_FEATURE_AMX_TILE }, 88 { X86_FEATURE_AMX_INT8, X86_FEATURE_AMX_TILE }, 89 { X86_FEATURE_SHSTK, X86_FEATURE_XSAVES }, 90 { X86_FEATURE_FRED, X86_FEATURE_LKGS }, 91 { X86_FEATURE_SPEC_CTRL_SSBD, X86_FEATURE_SPEC_CTRL }, 92 {} 93 }; 94 95 static inline void clear_feature(struct cpuinfo_x86 *c, unsigned int feature) 96 { 97 /* 98 * Note: This could use the non atomic __*_bit() variants, but the 99 * rest of the cpufeature code uses atomics as well, so keep it for 100 * consistency. Cleanup all of it separately. 101 */ 102 if (!c) { 103 clear_cpu_cap(&boot_cpu_data, feature); 104 set_bit(feature, (unsigned long *)cpu_caps_cleared); 105 } else { 106 clear_bit(feature, (unsigned long *)c->x86_capability); 107 } 108 } 109 110 /* Take the capabilities and the BUG bits into account */ 111 #define MAX_FEATURE_BITS ((NCAPINTS + NBUGINTS) * sizeof(u32) * 8) 112 113 static void do_clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int feature) 114 { 115 DECLARE_BITMAP(disable, MAX_FEATURE_BITS); 116 const struct cpuid_dep *d; 117 bool changed; 118 119 if (WARN_ON(feature >= MAX_FEATURE_BITS)) 120 return; 121 122 if (boot_cpu_has(feature)) 123 WARN_ON(alternatives_patched); 124 125 clear_feature(c, feature); 126 127 /* Collect all features to disable, handling dependencies */ 128 memset(disable, 0, sizeof(disable)); 129 __set_bit(feature, disable); 130 131 /* Loop until we get a stable state. */ 132 do { 133 changed = false; 134 for (d = cpuid_deps; d->feature; d++) { 135 if (!test_bit(d->depends, disable)) 136 continue; 137 if (__test_and_set_bit(d->feature, disable)) 138 continue; 139 140 changed = true; 141 clear_feature(c, d->feature); 142 } 143 } while (changed); 144 } 145 146 void clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int feature) 147 { 148 do_clear_cpu_cap(c, feature); 149 } 150 151 void setup_clear_cpu_cap(unsigned int feature) 152 { 153 do_clear_cpu_cap(NULL, feature); 154 } 155 156 /* 157 * Return the feature "name" if available, otherwise return 158 * the X86_FEATURE_* numerals to make it easier to identify 159 * the feature. 160 */ 161 static const char *x86_feature_name(unsigned int feature, char *buf) 162 { 163 if (x86_cap_flags[feature]) 164 return x86_cap_flags[feature]; 165 166 snprintf(buf, 16, "%d*32+%2d", feature / 32, feature % 32); 167 168 return buf; 169 } 170 171 void check_cpufeature_deps(struct cpuinfo_x86 *c) 172 { 173 char feature_buf[16], depends_buf[16]; 174 const struct cpuid_dep *d; 175 176 for (d = cpuid_deps; d->feature; d++) { 177 if (cpu_has(c, d->feature) && !cpu_has(c, d->depends)) { 178 /* 179 * Only warn about the first unmet dependency on the 180 * first CPU where it is encountered to avoid spamming 181 * the kernel log. 182 */ 183 pr_warn_once("x86 CPU feature dependency check failure: CPU%d has '%s' enabled but '%s' disabled. Kernel might be fine, but no guarantees.\n", 184 smp_processor_id(), 185 x86_feature_name(d->feature, feature_buf), 186 x86_feature_name(d->depends, depends_buf)); 187 } 188 } 189 } 190