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/* 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_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_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_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_SHSTK, X86_FEATURE_XSAVES },
{ X86_FEATURE_FRED, X86_FEATURE_LKGS },
{}
};
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));
}
}
}
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