/proc/cpuinfoでcpuの機能を表示するflagsのところってどうやって名称設定してんだろ？と思ったので調べてみたメモです。調べたカーネルのバージョンはv4.14.12です。
↓これですね
/proc/cpuinfoのopen処理
これはfs/proc/cpuinfo.cにあるcpuinfo_open()が担当します。と言っても、実際の処理はseq_operations構造体のcpuinfo_opに関数がセットされていて、それらが実行されます。
extern const struct seq_operations cpuinfo_op;
static int cpuinfo_open(struct inode *inode, struct file *file)
{
return seq_open(file, &cpuinfo_op);
}
ここからはアーキテクチャ固有になります。我らがx86_64ではarch/x86/kernel/cpu/proc.cにて以下のように設定を行っています。
onst struct seq_operations cpuinfo_op = {
.start = c_start,
.next = c_next,
.stop = c_stop,
.show = show_cpuinfo,
};
名前からしてshow_cpuinfo()を見れば良さそうに思えるのでこれを見てみます。
show_cpuinfo()
show_cpuinfo()が実際にcpuの情報を表示する関数です。
上から見ていくとこのようなところがみつかります。ここがflagsを出しているとこですね。
seq_puts(m, "flags\t\t:");
for (i = 0; i < 32*NCAPINTS; i++)
if (cpu_has(c, i) && x86_cap_flags[i] != NULL)
seq_printf(m, " %s", x86_cap_flags[i]);
seq_printf()はフォーマット指定子に%sを使っていて、引数はx86_cap_flags[i]なので、配列のx86_cap_flagsに名称が入ってるのがわかります。
そしたらx86_cap_flagsがどこで設定されてるか調べればOKですね。
x86_cap_flags配列
この配列ですが使ってるファイルは3ファイルです。
で、実際にこの配列に値を設定している箇所はmakeの実行前には存在しません(´・ω・`) なので、elixir.free-electrons.comだと見れないんですね。
x86_cap_flags配列の設定
ここで手元のカーネルになるので4.15.0-rc7になるんですが、arch/x86/kernel/cpu/capflags.cが設定している感じですね。
masami@saga:~/linux-kernel (test %)$ find arch/x86 -name "*.c" -o -name "*.h" | xargs grep -n "x86_cap_flags"
arch/x86/kernel/cpu/proc.c:102: if (cpu_has(c, i) && x86_cap_flags[i] != NULL)
arch/x86/kernel/cpu/proc.c:103: seq_printf(m, " %s", x86_cap_flags[i]);
arch/x86/kernel/cpu/capflags.c:5:const char * const x86_cap_flags[NCAPINTS*32] = {
arch/x86/boot/mkcpustr.c:32: str = x86_cap_flags[i*32+j];
arch/x86/include/asm/cpufeature.h:35:extern const char * const x86_cap_flags[NCAPINTS*32];
arch/x86/include/asm/cpufeature.h:38:#define x86_cap_flag(flag) x86_cap_flags[flag]
このファイルはこんな内容です。
#ifndef _ASM_X86_CPUFEATURES_H
#include <asm/cpufeatures.h>
#endif
const char * const x86_cap_flags[NCAPINTS*32] = {
[X86_FEATURE_FPU] = "fpu",
[X86_FEATURE_VME] = "vme",
[X86_FEATURE_DE] = "de",
[X86_FEATURE_PSE] = "pse",
[X86_FEATURE_TSC] = "tsc",
[X86_FEATURE_MSR] = "msr",
[X86_FEATURE_PAE] = "pae",
[X86_FEATURE_MCE] = "mce",
[X86_FEATURE_CX8] = "cx8",
[X86_FEATURE_APIC] = "apic",
[X86_FEATURE_SEP] = "sep",
[X86_FEATURE_MTRR] = "mtrr",
[X86_FEATURE_PGE] = "pge",
[X86_FEATURE_MCA] = "mca",
[X86_FEATURE_CMOV] = "cmov",
[X86_FEATURE_PAT] = "pat",
[X86_FEATURE_PSE36] = "pse36",
[X86_FEATURE_PN] = "pn",
[X86_FEATURE_CLFLUSH] = "clflush",
[X86_FEATURE_DS] = "dts",
[X86_FEATURE_ACPI] = "acpi",
[X86_FEATURE_MMX] = "mmx",
[X86_FEATURE_FXSR] = "fxsr",
[X86_FEATURE_XMM] = "sse",
[X86_FEATURE_XMM2] = "sse2",
[X86_FEATURE_SELFSNOOP] = "ss",
[X86_FEATURE_HT] = "ht",
[X86_FEATURE_ACC] = "tm",
[X86_FEATURE_IA64] = "ia64",
[X86_FEATURE_PBE] = "pbe",
[X86_FEATURE_SYSCALL] = "syscall",
[X86_FEATURE_MP] = "mp",
[X86_FEATURE_NX] = "nx",
[X86_FEATURE_MMXEXT] = "mmxext",
[X86_FEATURE_FXSR_OPT] = "fxsr_opt",
[X86_FEATURE_GBPAGES] = "pdpe1gb",
[X86_FEATURE_RDTSCP] = "rdtscp",
[X86_FEATURE_LM] = "lm",
[X86_FEATURE_3DNOWEXT] = "3dnowext",
[X86_FEATURE_3DNOW] = "3dnow",
[X86_FEATURE_RECOVERY] = "recovery",
[X86_FEATURE_LONGRUN] = "longrun",
[X86_FEATURE_LRTI] = "lrti",
[X86_FEATURE_CXMMX] = "cxmmx",
[X86_FEATURE_K6_MTRR] = "k6_mtrr",
[X86_FEATURE_CYRIX_ARR] = "cyrix_arr",
[X86_FEATURE_CENTAUR_MCR] = "centaur_mcr",
[X86_FEATURE_CONSTANT_TSC] = "constant_tsc",
[X86_FEATURE_UP] = "up",
[X86_FEATURE_ART] = "art",
[X86_FEATURE_ARCH_PERFMON] = "arch_perfmon",
[X86_FEATURE_PEBS] = "pebs",
[X86_FEATURE_BTS] = "bts",
[X86_FEATURE_REP_GOOD] = "rep_good",
[X86_FEATURE_ACC_POWER] = "acc_power",
[X86_FEATURE_NOPL] = "nopl",
[X86_FEATURE_XTOPOLOGY] = "xtopology",
[X86_FEATURE_TSC_RELIABLE] = "tsc_reliable",
[X86_FEATURE_NONSTOP_TSC] = "nonstop_tsc",
[X86_FEATURE_CPUID] = "cpuid",
[X86_FEATURE_EXTD_APICID] = "extd_apicid",
[X86_FEATURE_AMD_DCM] = "amd_dcm",
[X86_FEATURE_APERFMPERF] = "aperfmperf",
[X86_FEATURE_NONSTOP_TSC_S3] = "nonstop_tsc_s3",
[X86_FEATURE_TSC_KNOWN_FREQ] = "tsc_known_freq",
[X86_FEATURE_XMM3] = "pni",
[X86_FEATURE_PCLMULQDQ] = "pclmulqdq",
[X86_FEATURE_DTES64] = "dtes64",
[X86_FEATURE_MWAIT] = "monitor",
[X86_FEATURE_DSCPL] = "ds_cpl",
[X86_FEATURE_VMX] = "vmx",
[X86_FEATURE_SMX] = "smx",
[X86_FEATURE_EST] = "est",
[X86_FEATURE_TM2] = "tm2",
[X86_FEATURE_SSSE3] = "ssse3",
[X86_FEATURE_CID] = "cid",
[X86_FEATURE_SDBG] = "sdbg",
[X86_FEATURE_FMA] = "fma",
[X86_FEATURE_CX16] = "cx16",
[X86_FEATURE_XTPR] = "xtpr",
[X86_FEATURE_PDCM] = "pdcm",
[X86_FEATURE_PCID] = "pcid",
[X86_FEATURE_DCA] = "dca",
[X86_FEATURE_XMM4_1] = "sse4_1",
[X86_FEATURE_XMM4_2] = "sse4_2",
[X86_FEATURE_X2APIC] = "x2apic",
[X86_FEATURE_MOVBE] = "movbe",
[X86_FEATURE_POPCNT] = "popcnt",
[X86_FEATURE_TSC_DEADLINE_TIMER] = "tsc_deadline_timer",
[X86_FEATURE_AES] = "aes",
[X86_FEATURE_XSAVE] = "xsave",
[X86_FEATURE_AVX] = "avx",
[X86_FEATURE_F16C] = "f16c",
[X86_FEATURE_RDRAND] = "rdrand",
[X86_FEATURE_HYPERVISOR] = "hypervisor",
[X86_FEATURE_XSTORE] = "rng",
[X86_FEATURE_XSTORE_EN] = "rng_en",
[X86_FEATURE_XCRYPT] = "ace",
[X86_FEATURE_XCRYPT_EN] = "ace_en",
[X86_FEATURE_ACE2] = "ace2",
[X86_FEATURE_ACE2_EN] = "ace2_en",
[X86_FEATURE_PHE] = "phe",
[X86_FEATURE_PHE_EN] = "phe_en",
[X86_FEATURE_PMM] = "pmm",
[X86_FEATURE_PMM_EN] = "pmm_en",
[X86_FEATURE_LAHF_LM] = "lahf_lm",
[X86_FEATURE_CMP_LEGACY] = "cmp_legacy",
[X86_FEATURE_SVM] = "svm",
[X86_FEATURE_EXTAPIC] = "extapic",
[X86_FEATURE_CR8_LEGACY] = "cr8_legacy",
[X86_FEATURE_ABM] = "abm",
[X86_FEATURE_SSE4A] = "sse4a",
[X86_FEATURE_MISALIGNSSE] = "misalignsse",
[X86_FEATURE_3DNOWPREFETCH] = "3dnowprefetch",
[X86_FEATURE_OSVW] = "osvw",
[X86_FEATURE_IBS] = "ibs",
[X86_FEATURE_XOP] = "xop",
[X86_FEATURE_SKINIT] = "skinit",
[X86_FEATURE_WDT] = "wdt",
[X86_FEATURE_LWP] = "lwp",
[X86_FEATURE_FMA4] = "fma4",
[X86_FEATURE_TCE] = "tce",
[X86_FEATURE_NODEID_MSR] = "nodeid_msr",
[X86_FEATURE_TBM] = "tbm",
[X86_FEATURE_TOPOEXT] = "topoext",
[X86_FEATURE_PERFCTR_CORE] = "perfctr_core",
[X86_FEATURE_PERFCTR_NB] = "perfctr_nb",
[X86_FEATURE_BPEXT] = "bpext",
[X86_FEATURE_PTSC] = "ptsc",
[X86_FEATURE_PERFCTR_LLC] = "perfctr_llc",
[X86_FEATURE_MWAITX] = "mwaitx",
[X86_FEATURE_RING3MWAIT] = "ring3mwait",
[X86_FEATURE_CPUID_FAULT] = "cpuid_fault",
[X86_FEATURE_CPB] = "cpb",
[X86_FEATURE_EPB] = "epb",
[X86_FEATURE_CAT_L3] = "cat_l3",
[X86_FEATURE_CAT_L2] = "cat_l2",
[X86_FEATURE_CDP_L3] = "cdp_l3",
[X86_FEATURE_INVPCID_SINGLE] = "invpcid_single",
[X86_FEATURE_HW_PSTATE] = "hw_pstate",
[X86_FEATURE_PROC_FEEDBACK] = "proc_feedback",
[X86_FEATURE_SME] = "sme",
[X86_FEATURE_PTI] = "pti",
[X86_FEATURE_INTEL_PPIN] = "intel_ppin",
[X86_FEATURE_INTEL_PT] = "intel_pt",
[X86_FEATURE_AVX512_4VNNIW] = "avx512_4vnniw",
[X86_FEATURE_AVX512_4FMAPS] = "avx512_4fmaps",
[X86_FEATURE_MBA] = "mba",
[X86_FEATURE_TPR_SHADOW] = "tpr_shadow",
[X86_FEATURE_VNMI] = "vnmi",
[X86_FEATURE_FLEXPRIORITY] = "flexpriority",
[X86_FEATURE_EPT] = "ept",
[X86_FEATURE_VPID] = "vpid",
[X86_FEATURE_VMMCALL] = "vmmcall",
[X86_FEATURE_FSGSBASE] = "fsgsbase",
[X86_FEATURE_TSC_ADJUST] = "tsc_adjust",
[X86_FEATURE_BMI1] = "bmi1",
[X86_FEATURE_HLE] = "hle",
[X86_FEATURE_AVX2] = "avx2",
[X86_FEATURE_SMEP] = "smep",
[X86_FEATURE_BMI2] = "bmi2",
[X86_FEATURE_ERMS] = "erms",
[X86_FEATURE_INVPCID] = "invpcid",
[X86_FEATURE_RTM] = "rtm",
[X86_FEATURE_CQM] = "cqm",
[X86_FEATURE_MPX] = "mpx",
[X86_FEATURE_RDT_A] = "rdt_a",
[X86_FEATURE_AVX512F] = "avx512f",
[X86_FEATURE_AVX512DQ] = "avx512dq",
[X86_FEATURE_RDSEED] = "rdseed",
[X86_FEATURE_ADX] = "adx",
[X86_FEATURE_SMAP] = "smap",
[X86_FEATURE_AVX512IFMA] = "avx512ifma",
[X86_FEATURE_CLFLUSHOPT] = "clflushopt",
[X86_FEATURE_CLWB] = "clwb",
[X86_FEATURE_AVX512PF] = "avx512pf",
[X86_FEATURE_AVX512ER] = "avx512er",
[X86_FEATURE_AVX512CD] = "avx512cd",
[X86_FEATURE_SHA_NI] = "sha_ni",
[X86_FEATURE_AVX512BW] = "avx512bw",
[X86_FEATURE_AVX512VL] = "avx512vl",
[X86_FEATURE_XSAVEOPT] = "xsaveopt",
[X86_FEATURE_XSAVEC] = "xsavec",
[X86_FEATURE_XGETBV1] = "xgetbv1",
[X86_FEATURE_XSAVES] = "xsaves",
[X86_FEATURE_CQM_LLC] = "cqm_llc",
[X86_FEATURE_CQM_OCCUP_LLC] = "cqm_occup_llc",
[X86_FEATURE_CQM_MBM_TOTAL] = "cqm_mbm_total",
[X86_FEATURE_CQM_MBM_LOCAL] = "cqm_mbm_local",
[X86_FEATURE_CLZERO] = "clzero",
[X86_FEATURE_IRPERF] = "irperf",
[X86_FEATURE_XSAVEERPTR] = "xsaveerptr",
[X86_FEATURE_DTHERM] = "dtherm",
[X86_FEATURE_IDA] = "ida",
[X86_FEATURE_ARAT] = "arat",
[X86_FEATURE_PLN] = "pln",
[X86_FEATURE_PTS] = "pts",
[X86_FEATURE_HWP] = "hwp",
[X86_FEATURE_HWP_NOTIFY] = "hwp_notify",
[X86_FEATURE_HWP_ACT_WINDOW] = "hwp_act_window",
[X86_FEATURE_HWP_EPP] = "hwp_epp",
[X86_FEATURE_HWP_PKG_REQ] = "hwp_pkg_req",
[X86_FEATURE_NPT] = "npt",
[X86_FEATURE_LBRV] = "lbrv",
[X86_FEATURE_SVML] = "svm_lock",
[X86_FEATURE_NRIPS] = "nrip_save",
[X86_FEATURE_TSCRATEMSR] = "tsc_scale",
[X86_FEATURE_VMCBCLEAN] = "vmcb_clean",
[X86_FEATURE_FLUSHBYASID] = "flushbyasid",
[X86_FEATURE_DECODEASSISTS] = "decodeassists",
[X86_FEATURE_PAUSEFILTER] = "pausefilter",
[X86_FEATURE_PFTHRESHOLD] = "pfthreshold",
[X86_FEATURE_AVIC] = "avic",
[X86_FEATURE_V_VMSAVE_VMLOAD] = "v_vmsave_vmload",
[X86_FEATURE_VGIF] = "vgif",
[X86_FEATURE_AVX512VBMI] = "avx512vbmi",
[X86_FEATURE_UMIP] = "umip",
[X86_FEATURE_PKU] = "pku",
[X86_FEATURE_OSPKE] = "ospke",
[X86_FEATURE_AVX512_VBMI2] = "avx512_vbmi2",
[X86_FEATURE_GFNI] = "gfni",
[X86_FEATURE_VAES] = "vaes",
[X86_FEATURE_VPCLMULQDQ] = "vpclmulqdq",
[X86_FEATURE_AVX512_VNNI] = "avx512_vnni",
[X86_FEATURE_AVX512_BITALG] = "avx512_bitalg",
[X86_FEATURE_AVX512_VPOPCNTDQ] = "avx512_vpopcntdq",
[X86_FEATURE_LA57] = "la57",
[X86_FEATURE_RDPID] = "rdpid",
[X86_FEATURE_OVERFLOW_RECOV] = "overflow_recov",
[X86_FEATURE_SUCCOR] = "succor",
[X86_FEATURE_SMCA] = "smca",
};
const char * const x86_bug_flags[NBUGINTS*32] = {
[X86_BUG_F00F - NCAPINTS*32] = "f00f",
[X86_BUG_FDIV - NCAPINTS*32] = "fdiv",
[X86_BUG_COMA - NCAPINTS*32] = "coma",
[X86_BUG_AMD_TLB_MMATCH - NCAPINTS*32] = "tlb_mmatch",
[X86_BUG_AMD_APIC_C1E - NCAPINTS*32] = "apic_c1e",
[X86_BUG_11AP - NCAPINTS*32] = "11ap",
[X86_BUG_FXSAVE_LEAK - NCAPINTS*32] = "fxsave_leak",
[X86_BUG_CLFLUSH_MONITOR - NCAPINTS*32] = "clflush_monitor",
[X86_BUG_SYSRET_SS_ATTRS - NCAPINTS*32] = "sysret_ss_attrs",
[X86_BUG_NULL_SEG - NCAPINTS*32] = "null_seg",
[X86_BUG_SWAPGS_FENCE - NCAPINTS*32] = "swapgs_fence",
[X86_BUG_MONITOR - NCAPINTS*32] = "monitor",
[X86_BUG_AMD_E400 - NCAPINTS*32] = "amd_e400",
[X86_BUG_CPU_MELTDOWN - NCAPINTS*32] = "cpu_meltdown",
};
そして、このファイルがどのように作られるかと言うと、./arch/x86/kernel/cpu/Makefileの以下の部分です。mkcapflags.shというシェルスクリプトを実行してそこからファイルを作ってます。
ifdef CONFIG_X86_FEATURE_NAMES
quiet_cmd_mkcapflags = MKCAP $@
cmd_mkcapflags = $(CONFIG_SHELL) $(srctree)/$(src)/mkcapflags.sh $< $@
cpufeature = $(src)/../../include/asm/cpufeatures.h
targets += capflags.c
$(obj)/capflags.c: $(cpufeature) $(src)/mkcapflags.sh FORCE
$(call if_changed,mkcapflags)
endif
まとめ
flagsに表示する機能の名前は配列で定義されていて、その配列はカーネルのコンパイル中に作られます。
