diff options
Diffstat (limited to 'arch/x86/kernel/cpu/cpuid-deps.c')
| -rw-r--r-- | arch/x86/kernel/cpu/cpuid-deps.c | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/cpuid-deps.c b/arch/x86/kernel/cpu/cpuid-deps.c new file mode 100644 index 000000000000..146f6f8b0650 --- /dev/null +++ b/arch/x86/kernel/cpu/cpuid-deps.c @@ -0,0 +1,192 @@ +/* Declare dependencies between CPUIDs */ +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/module.h> +#include <asm/cpufeature.h> + +struct cpuid_dep { + unsigned int feature; + unsigned int depends; +}; + +/* + * Table of CPUID features that depend on others. + * + * This only includes dependencies that can be usefully disabled, not + * features part of the base set (like FPU). + * + * Note this all is not __init / __initdata because it can be + * called from cpu hotplug. It shouldn't do anything in this case, + * but it's difficult to tell that to the init reference checker. + */ +static const struct cpuid_dep cpuid_deps[] = { + { X86_FEATURE_FXSR, X86_FEATURE_FPU }, + { X86_FEATURE_XSAVEOPT, X86_FEATURE_XSAVE }, + { X86_FEATURE_XSAVEC, X86_FEATURE_XSAVE }, + { X86_FEATURE_XSAVES, X86_FEATURE_XSAVE }, + { X86_FEATURE_AVX, X86_FEATURE_XSAVE }, + { X86_FEATURE_PKU, X86_FEATURE_XSAVE }, + { X86_FEATURE_MPX, X86_FEATURE_XSAVE }, + { X86_FEATURE_XGETBV1, X86_FEATURE_XSAVE }, + { X86_FEATURE_APX, X86_FEATURE_XSAVE }, + { X86_FEATURE_CMOV, X86_FEATURE_FXSR }, + { X86_FEATURE_MMX, X86_FEATURE_FXSR }, + { X86_FEATURE_MMXEXT, X86_FEATURE_MMX }, + { X86_FEATURE_FXSR_OPT, X86_FEATURE_FXSR }, + { X86_FEATURE_XSAVE, X86_FEATURE_FXSR }, + { X86_FEATURE_XMM, X86_FEATURE_FXSR }, + { X86_FEATURE_XMM2, X86_FEATURE_XMM }, + { X86_FEATURE_XMM3, X86_FEATURE_XMM2 }, + { X86_FEATURE_XMM4_1, X86_FEATURE_XMM2 }, + { X86_FEATURE_XMM4_2, X86_FEATURE_XMM2 }, + { X86_FEATURE_XMM3, X86_FEATURE_XMM2 }, + { X86_FEATURE_PCLMULQDQ, X86_FEATURE_XMM2 }, + { X86_FEATURE_SSSE3, X86_FEATURE_XMM2, }, + { X86_FEATURE_F16C, X86_FEATURE_XMM2, }, + { X86_FEATURE_AES, X86_FEATURE_XMM2 }, + { X86_FEATURE_SHA_NI, X86_FEATURE_XMM2 }, + { X86_FEATURE_GFNI, X86_FEATURE_XMM2 }, + { X86_FEATURE_AVX_VNNI, X86_FEATURE_AVX }, + { X86_FEATURE_FMA, X86_FEATURE_AVX }, + { X86_FEATURE_VAES, X86_FEATURE_AVX }, + { X86_FEATURE_VPCLMULQDQ, X86_FEATURE_AVX }, + { X86_FEATURE_AVX2, X86_FEATURE_AVX, }, + { X86_FEATURE_AVX512F, X86_FEATURE_AVX, }, + { X86_FEATURE_AVX512IFMA, X86_FEATURE_AVX512F }, + { X86_FEATURE_AVX512PF, X86_FEATURE_AVX512F }, + { X86_FEATURE_AVX512ER, X86_FEATURE_AVX512F }, + { X86_FEATURE_AVX512CD, X86_FEATURE_AVX512F }, + { X86_FEATURE_AVX512DQ, X86_FEATURE_AVX512F }, + { X86_FEATURE_AVX512BW, X86_FEATURE_AVX512F }, + { X86_FEATURE_AVX512VL, X86_FEATURE_AVX512F }, + { X86_FEATURE_AVX512VBMI, X86_FEATURE_AVX512F }, + { X86_FEATURE_AVX512_VBMI2, X86_FEATURE_AVX512VL }, + { X86_FEATURE_AVX512_VNNI, X86_FEATURE_AVX512VL }, + { X86_FEATURE_AVX512_BITALG, X86_FEATURE_AVX512VL }, + { X86_FEATURE_AVX512_4VNNIW, X86_FEATURE_AVX512F }, + { X86_FEATURE_AVX512_4FMAPS, X86_FEATURE_AVX512F }, + { X86_FEATURE_AVX512_VPOPCNTDQ, X86_FEATURE_AVX512F }, + { X86_FEATURE_AVX512_VP2INTERSECT, X86_FEATURE_AVX512VL }, + { X86_FEATURE_CQM_OCCUP_LLC, X86_FEATURE_CQM_LLC }, + { X86_FEATURE_CQM_MBM_TOTAL, X86_FEATURE_CQM_LLC }, + { X86_FEATURE_CQM_MBM_LOCAL, X86_FEATURE_CQM_LLC }, + { X86_FEATURE_BMEC, X86_FEATURE_CQM_MBM_TOTAL }, + { X86_FEATURE_BMEC, X86_FEATURE_CQM_MBM_LOCAL }, + { X86_FEATURE_SDCIAE, X86_FEATURE_CAT_L3 }, + { X86_FEATURE_AVX512_BF16, X86_FEATURE_AVX512VL }, + { X86_FEATURE_AVX512_FP16, X86_FEATURE_AVX512BW }, + { X86_FEATURE_ENQCMD, X86_FEATURE_XSAVES }, + { X86_FEATURE_PER_THREAD_MBA, X86_FEATURE_MBA }, + { X86_FEATURE_SGX_LC, X86_FEATURE_SGX }, + { X86_FEATURE_SGX1, X86_FEATURE_SGX }, + { X86_FEATURE_SGX2, X86_FEATURE_SGX1 }, + { X86_FEATURE_SGX_EUPDATESVN, X86_FEATURE_SGX1 }, + { X86_FEATURE_SGX_EDECCSSA, X86_FEATURE_SGX1 }, + { X86_FEATURE_XFD, X86_FEATURE_XSAVES }, + { X86_FEATURE_XFD, X86_FEATURE_XGETBV1 }, + { X86_FEATURE_AMX_TILE, X86_FEATURE_XFD }, + { X86_FEATURE_AMX_FP16, X86_FEATURE_AMX_TILE }, + { X86_FEATURE_AMX_BF16, X86_FEATURE_AMX_TILE }, + { X86_FEATURE_AMX_INT8, X86_FEATURE_AMX_TILE }, + { X86_FEATURE_SHSTK, X86_FEATURE_XSAVES }, + { X86_FEATURE_FRED, X86_FEATURE_LKGS }, + { X86_FEATURE_SPEC_CTRL_SSBD, X86_FEATURE_SPEC_CTRL }, + { X86_FEATURE_LASS, X86_FEATURE_SMAP }, + {} +}; + +static inline void clear_feature(struct cpuinfo_x86 *c, unsigned int feature) +{ + /* + * Note: This could use the non atomic __*_bit() variants, but the + * rest of the cpufeature code uses atomics as well, so keep it for + * consistency. Cleanup all of it separately. + */ + if (!c) { + clear_cpu_cap(&boot_cpu_data, feature); + set_bit(feature, (unsigned long *)cpu_caps_cleared); + } else { + clear_bit(feature, (unsigned long *)c->x86_capability); + } +} + +/* Take the capabilities and the BUG bits into account */ +#define MAX_FEATURE_BITS ((NCAPINTS + NBUGINTS) * sizeof(u32) * 8) + +static void do_clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int feature) +{ + DECLARE_BITMAP(disable, MAX_FEATURE_BITS); + const struct cpuid_dep *d; + bool changed; + + if (WARN_ON(feature >= MAX_FEATURE_BITS)) + return; + + if (boot_cpu_has(feature)) + WARN_ON(alternatives_patched); + + clear_feature(c, feature); + + /* Collect all features to disable, handling dependencies */ + memset(disable, 0, sizeof(disable)); + __set_bit(feature, disable); + + /* Loop until we get a stable state. */ + do { + changed = false; + for (d = cpuid_deps; d->feature; d++) { + if (!test_bit(d->depends, disable)) + continue; + if (__test_and_set_bit(d->feature, disable)) + continue; + + changed = true; + clear_feature(c, d->feature); + } + } while (changed); +} + +void clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int feature) +{ + do_clear_cpu_cap(c, feature); +} + +void setup_clear_cpu_cap(unsigned int feature) +{ + do_clear_cpu_cap(NULL, feature); +} + +/* + * Return the feature "name" if available, otherwise return + * the X86_FEATURE_* numerals to make it easier to identify + * the feature. + */ +static const char *x86_feature_name(unsigned int feature, char *buf) +{ + if (x86_cap_flags[feature]) + return x86_cap_flags[feature]; + + snprintf(buf, 16, "%d*32+%2d", feature / 32, feature % 32); + + return buf; +} + +void check_cpufeature_deps(struct cpuinfo_x86 *c) +{ + char feature_buf[16], depends_buf[16]; + const struct cpuid_dep *d; + + for (d = cpuid_deps; d->feature; d++) { + if (cpu_has(c, d->feature) && !cpu_has(c, d->depends)) { + /* + * Only warn about the first unmet dependency on the + * first CPU where it is encountered to avoid spamming + * the kernel log. + */ + 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", + smp_processor_id(), + x86_feature_name(d->feature, feature_buf), + x86_feature_name(d->depends, depends_buf)); + } + } +} |