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cpuinfo: x86 -- Rework cpuinfo features fetching
Instead of parsing procfs lets use native cpuid(), it's a way faster. The dark side is that the kernel may disable some of features via bootline options even if they are present on hardware but for us it's fine -- we will be testing hardware cpu for features anyway. The X86_FEATURE_ bits are gathered from two sources: linux kernel and cpu specifications. Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
This commit is contained in:
Cyrill Gorcunov
Pavel Emelyanov
parent
2581dcfb22
commit
de770e023a
2 changed files with 180 additions and 21 deletions
180
arch/x86/cpu.c
180
arch/x86/cpu.c
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@ -22,41 +22,181 @@
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#undef LOG_PREFIX
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#define LOG_PREFIX "cpu: "
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const char * const x86_cap_flags[NCAPINTS_BITS] = {
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[X86_FEATURE_FPU] = "fpu",
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[X86_FEATURE_FXSR] = "fxsr",
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[X86_FEATURE_XSAVE] = "xsave",
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};
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static struct cpuinfo_x86 rt_cpu_info;
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static DECLARE_BITMAP(cpu_features, NCAPINTS_BITS);
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static void cpu_set_feature(unsigned int feature)
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static void set_cpu_cap(struct cpuinfo_x86 *c, unsigned int feature)
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{
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if (likely(feature < NCAPINTS_BITS))
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set_bit(feature, cpu_features);
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set_bit(feature, (unsigned long *)c->x86_capability);
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}
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static void clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int feature)
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{
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if (likely(feature < NCAPINTS_BITS))
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clear_bit(feature, (unsigned long *)c->x86_capability);
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}
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static int test_cpu_cap(struct cpuinfo_x86 *c, unsigned int feature)
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{
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if (likely(feature < NCAPINTS_BITS))
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return test_bit(feature, (unsigned long *)c->x86_capability);
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return 0;
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}
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bool cpu_has_feature(unsigned int feature)
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{
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if (likely(feature < NCAPINTS_BITS))
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return test_bit(feature, cpu_features);
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return false;
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return test_cpu_cap(&rt_cpu_info, feature);
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}
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static int proc_cpuinfo_match(char *tok)
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static int cpu_init_cpuid(struct cpuinfo_x86 *c)
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{
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if (!strcmp(tok, x86_cap_flags[X86_FEATURE_FXSR]))
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cpu_set_feature(X86_FEATURE_FXSR);
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else if (!strcmp(tok, x86_cap_flags[X86_FEATURE_XSAVE]))
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cpu_set_feature(X86_FEATURE_XSAVE);
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else if (!strcmp(tok, x86_cap_flags[X86_FEATURE_FPU]))
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cpu_set_feature(X86_FEATURE_FPU);
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/*
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* See cpu_detect() in the kernel, also
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* read cpuid specs not only from general
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* SDM but for extended instructions set
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* reference.
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*/
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/* Get vendor name */
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cpuid(0x00000000,
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(unsigned int *)&c->cpuid_level,
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(unsigned int *)&c->x86_vendor_id[0],
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(unsigned int *)&c->x86_vendor_id[8],
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(unsigned int *)&c->x86_vendor_id[4]);
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if (!strcmp(c->x86_vendor_id, "GenuineIntel")) {
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c->x86_vendor = X86_VENDOR_INTEL;
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} else if (!strcmp(c->x86_vendor_id, "AuthenticAMD")) {
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c->x86_vendor = X86_VENDOR_AMD;
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} else {
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pr_err("Unsupported CPU vendor %s\n",
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c->x86_vendor_id);
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return -1;
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}
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c->x86_family = 4;
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/* Intel-defined flags: level 0x00000001 */
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if (c->cpuid_level >= 0x00000001) {
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u32 eax, ebx, ecx, edx;
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cpuid(0x00000001, &eax, &ebx, &ecx, &edx);
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c->x86_family = (eax >> 8) & 0xf;
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c->x86_model = (eax >> 4) & 0xf;
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c->x86_mask = eax & 0xf;
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if (c->x86_family == 0xf)
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c->x86_family += (eax >> 20) & 0xff;
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if (c->x86_family >= 0x6)
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c->x86_model += ((eax >> 16) & 0xf) << 4;
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c->x86_capability[0] = edx;
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c->x86_capability[4] = ecx;
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}
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/* Additional Intel-defined flags: level 0x00000007 */
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if (c->cpuid_level >= 0x00000007) {
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u32 eax, ebx, ecx, edx;
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cpuid_count(0x00000007, 0, &eax, &ebx, &ecx, &edx);
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c->x86_capability[9] = ebx;
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c->x86_capability[11] = ecx;
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}
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/* Extended state features: level 0x0000000d */
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if (c->cpuid_level >= 0x0000000d) {
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u32 eax, ebx, ecx, edx;
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cpuid_count(0x0000000d, 1, &eax, &ebx, &ecx, &edx);
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c->x86_capability[10] = eax;
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}
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/* AMD-defined flags: level 0x80000001 */
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c->extended_cpuid_level = cpuid_eax(0x80000000);
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if ((c->extended_cpuid_level & 0xffff0000) == 0x80000000) {
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if (c->extended_cpuid_level >= 0x80000001) {
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c->x86_capability[1] = cpuid_edx(0x80000001);
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c->x86_capability[6] = cpuid_ecx(0x80000001);
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}
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}
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/*
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* We're don't care about scattered features for now,
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* otherwise look into init_scattered_cpuid_features()
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* in kernel.
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*/
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if (c->extended_cpuid_level >= 0x80000004) {
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unsigned int *v;
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char *p, *q;
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v = (unsigned int *)c->x86_model_id;
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cpuid(0x80000002, &v[0], &v[1], &v[2], &v[3]);
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cpuid(0x80000003, &v[4], &v[5], &v[6], &v[7]);
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cpuid(0x80000004, &v[8], &v[9], &v[10], &v[11]);
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c->x86_model_id[48] = 0;
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/*
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* Intel chips right-justify this string for some dumb reason;
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* undo that brain damage:
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*/
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p = q = &c->x86_model_id[0];
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while (*p == ' ')
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p++;
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if (p != q) {
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while (*p)
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*q++ = *p++;
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while (q <= &c->x86_model_id[48])
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*q++ = '\0'; /* Zero-pad the rest */
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}
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}
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/* On x86-64 NOP is always present */
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set_cpu_cap(c, X86_FEATURE_NOPL);
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switch (c->x86_vendor) {
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case X86_VENDOR_INTEL:
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/*
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* Strictly speaking we need to read MSR_IA32_MISC_ENABLE
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* here but on ring3 it's impossible.
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*/
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if (c->x86_family == 15) {
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clear_cpu_cap(c, X86_FEATURE_REP_GOOD);
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clear_cpu_cap(c, X86_FEATURE_ERMS);
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} else if (c->x86_family == 6) {
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/* On x86-64 rep is fine */
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set_cpu_cap(c, X86_FEATURE_REP_GOOD);
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}
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/* See filter_cpuid_features in kernel */
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if ((s32)c->cpuid_level < (s32)0x0000000d)
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clear_cpu_cap(c, X86_FEATURE_XSAVE);
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break;
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case X86_VENDOR_AMD:
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/*
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* Bit 31 in normal CPUID used for nonstandard 3DNow ID;
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* 3DNow is IDd by bit 31 in extended CPUID (1*32+31) anyway
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*/
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clear_cpu_cap(c, 0 * 32 + 31);
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if (c->x86_family >= 0x10)
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set_cpu_cap(c, X86_FEATURE_REP_GOOD);
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if (c->x86_family == 0xf) {
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u32 level;
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/* On C+ stepping K8 rep microcode works well for copy/memset */
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level = cpuid_eax(1);
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if ((level >= 0x0f48 && level < 0x0f50) || level >= 0x0f58)
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set_cpu_cap(c, X86_FEATURE_REP_GOOD);
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}
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break;
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}
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return 0;
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}
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int cpu_init(void)
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{
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if (parse_cpuinfo_features(proc_cpuinfo_match))
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if (cpu_init_cpuid(&rt_cpu_info))
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return -1;
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BUILD_BUG_ON(sizeof(struct xsave_struct) != XSAVE_SIZE);
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@ -176,7 +176,26 @@ static inline unsigned int cpuid_edx(unsigned int op)
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return edx;
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}
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extern const char * const x86_cap_flags[NCAPINTS_BITS];
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#define X86_FEATURE_VERSION 1
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enum {
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X86_VENDOR_INTEL = 0,
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X86_VENDOR_AMD = 1,
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X86_VENDOR_MAX
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};
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struct cpuinfo_x86 {
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u8 x86_family;
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u8 x86_vendor;
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u8 x86_model;
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u8 x86_mask;
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u32 x86_capability[NCAPINTS];
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u32 extended_cpuid_level;
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int cpuid_level;
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char x86_vendor_id[16];
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char x86_model_id[64];
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};
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extern bool cpu_has_feature(unsigned int feature);
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extern int cpu_init(void);
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