Linux2011.03.22 09:37
fpu Onboard (x87) Floating Point Unit
vme Virtual Mode Extension
de Debugging Extensions
pse Page Size Extensions
tsc Time Stamp Counter: support for RDTSC and WRTSC instructions
msr Model-Specific Registers
pae Physical Address Extensions: ability to access 64GB of memory; only 4GB can be accessed at a time though
mce Machine Check Architecture
cx8 CMPXCHG8 instruction
apic Onboard Advanced Programmable Interrupt Controller
sep Sysenter/Sysexit Instructions; SYSENTER is used for jumps to kernel memory during system calls, and SYSEXIT is used for jumps back to the user code
mtrr Memory Type Range Registers
pge Page Global Enable
mca Machine Check Architecture
cmov CMOV instruction
pat Page Attribute Table
pse36 36-bit Page Size Extensions: allows to map 4 MB pages into the first 64GB RAM, used with PSE.
pn Processor Serial-Number; only available on Pentium 3
clflush CLFLUSH instruction
dtes Debug Trace Store
acpi ACPI via MSR
mmx MultiMedia Extension
fxsr FXSAVE and FXSTOR instructions
sse Streaming SIMD Extensions. Single instruction multiple data. Lets you do a bunch of the same operation on different pieces of input in a single clock tick.
sse2 Streaming SIMD Extensions-2. More of the same.
selfsnoop CPU self snoop
acc Automatic Clock Control
IA64 IA-64 processor Itanium.
ht HyperThreading. Introduces an imaginary second processor that doesn’t do much but lets you run threads in the same process a bit quicker.
nx No Execute bit. Prevents arbitrary code running via buffer overflows.
pni Prescott New Instructions aka. SSE3
vmx Intel Vanderpool hardware virtualization technology
svm AMD “Pacifica” hardware virtualization technology
lm “Long Mode,” which means the chip supports the AMD64 instruction set
tm “Thermal Monitor” Thermal throttling with IDLE instructions.
      Usually hardware controlled in response to CPU temperature.
tm2 “Thermal Monitor 2″ Decrease speed by reducing multipler and vcore.
est “Enhanced SpeedStep” 

 \flags           : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc arch_perfmon pebs bts aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm lahf_lm tpr_shadow  

커널소스에 내용이 들어있다고 하는데 알아볼수가 없네 -_- 
아무튼 아래는 2.6.38 버전의 /usr/include/asm/cpufeature.h 파일내용
/*
 * Defines x86 CPU feature bits
 */
#ifndef _ASM_X86_CPUFEATURE_H
#define _ASM_X86_CPUFEATURE_H

#include "asm/required-features.h"

#define NCAPINTS	10	/* N 32-bit words worth of info */

/*
 * Note: If the comment begins with a quoted string, that string is used
 * in /proc/cpuinfo instead of the macro name.  If the string is "",
 * this feature bit is not displayed in /proc/cpuinfo at all.
 */

/* Intel-defined CPU features, CPUID level 0x00000001 (edx), word 0 */
#define X86_FEATURE_FPU		(0*32+ 0) /* Onboard FPU */
#define X86_FEATURE_VME		(0*32+ 1) /* Virtual Mode Extensions */
#define X86_FEATURE_DE		(0*32+ 2) /* Debugging Extensions */
#define X86_FEATURE_PSE		(0*32+ 3) /* Page Size Extensions */
#define X86_FEATURE_TSC		(0*32+ 4) /* Time Stamp Counter */
#define X86_FEATURE_MSR		(0*32+ 5) /* Model-Specific Registers */
#define X86_FEATURE_PAE		(0*32+ 6) /* Physical Address Extensions */
#define X86_FEATURE_MCE		(0*32+ 7) /* Machine Check Exception */
#define X86_FEATURE_CX8		(0*32+ 8) /* CMPXCHG8 instruction */
#define X86_FEATURE_APIC	(0*32+ 9) /* Onboard APIC */
#define X86_FEATURE_SEP		(0*32+11) /* SYSENTER/SYSEXIT */
#define X86_FEATURE_MTRR	(0*32+12) /* Memory Type Range Registers */
#define X86_FEATURE_PGE		(0*32+13) /* Page Global Enable */
#define X86_FEATURE_MCA		(0*32+14) /* Machine Check Architecture */
#define X86_FEATURE_CMOV	(0*32+15) /* CMOV instructions */
					  /* (plus FCMOVcc, FCOMI with FPU) */
#define X86_FEATURE_PAT		(0*32+16) /* Page Attribute Table */
#define X86_FEATURE_PSE36	(0*32+17) /* 36-bit PSEs */
#define X86_FEATURE_PN		(0*32+18) /* Processor serial number */
#define X86_FEATURE_CLFLSH	(0*32+19) /* "clflush" CLFLUSH instruction */
#define X86_FEATURE_DS		(0*32+21) /* "dts" Debug Store */
#define X86_FEATURE_ACPI	(0*32+22) /* ACPI via MSR */
#define X86_FEATURE_MMX		(0*32+23) /* Multimedia Extensions */
#define X86_FEATURE_FXSR	(0*32+24) /* FXSAVE/FXRSTOR, CR4.OSFXSR */
#define X86_FEATURE_XMM		(0*32+25) /* "sse" */
#define X86_FEATURE_XMM2	(0*32+26) /* "sse2" */
#define X86_FEATURE_SELFSNOOP	(0*32+27) /* "ss" CPU self snoop */
#define X86_FEATURE_HT		(0*32+28) /* Hyper-Threading */
#define X86_FEATURE_ACC		(0*32+29) /* "tm" Automatic clock control */
#define X86_FEATURE_IA64	(0*32+30) /* IA-64 processor */
#define X86_FEATURE_PBE		(0*32+31) /* Pending Break Enable */

/* AMD-defined CPU features, CPUID level 0x80000001, word 1 */
/* Don't duplicate feature flags which are redundant with Intel! */
#define X86_FEATURE_SYSCALL	(1*32+11) /* SYSCALL/SYSRET */
#define X86_FEATURE_MP		(1*32+19) /* MP Capable. */
#define X86_FEATURE_NX		(1*32+20) /* Execute Disable */
#define X86_FEATURE_MMXEXT	(1*32+22) /* AMD MMX extensions */
#define X86_FEATURE_FXSR_OPT	(1*32+25) /* FXSAVE/FXRSTOR optimizations */
#define X86_FEATURE_GBPAGES	(1*32+26) /* "pdpe1gb" GB pages */
#define X86_FEATURE_RDTSCP	(1*32+27) /* RDTSCP */
#define X86_FEATURE_LM		(1*32+29) /* Long Mode (x86-64) */
#define X86_FEATURE_3DNOWEXT	(1*32+30) /* AMD 3DNow! extensions */
#define X86_FEATURE_3DNOW	(1*32+31) /* 3DNow! */

/* Transmeta-defined CPU features, CPUID level 0x80860001, word 2 */
#define X86_FEATURE_RECOVERY	(2*32+ 0) /* CPU in recovery mode */
#define X86_FEATURE_LONGRUN	(2*32+ 1) /* Longrun power control */
#define X86_FEATURE_LRTI	(2*32+ 3) /* LongRun table interface */

/* Other features, Linux-defined mapping, word 3 */
/* This range is used for feature bits which conflict or are synthesized */
#define X86_FEATURE_CXMMX	(3*32+ 0) /* Cyrix MMX extensions */
#define X86_FEATURE_K6_MTRR	(3*32+ 1) /* AMD K6 nonstandard MTRRs */
#define X86_FEATURE_CYRIX_ARR	(3*32+ 2) /* Cyrix ARRs (= MTRRs) */
#define X86_FEATURE_CENTAUR_MCR	(3*32+ 3) /* Centaur MCRs (= MTRRs) */
/* cpu types for specific tunings: */
#define X86_FEATURE_K8		(3*32+ 4) /* "" Opteron, Athlon64 */
#define X86_FEATURE_K7		(3*32+ 5) /* "" Athlon */
#define X86_FEATURE_P3		(3*32+ 6) /* "" P3 */
#define X86_FEATURE_P4		(3*32+ 7) /* "" P4 */
#define X86_FEATURE_CONSTANT_TSC (3*32+ 8) /* TSC ticks at a constant rate */
#define X86_FEATURE_UP		(3*32+ 9) /* smp kernel running on up */
#define X86_FEATURE_FXSAVE_LEAK (3*32+10) /* "" FXSAVE leaks FOP/FIP/FOP */
#define X86_FEATURE_ARCH_PERFMON (3*32+11) /* Intel Architectural PerfMon */
#define X86_FEATURE_PEBS	(3*32+12) /* Precise-Event Based Sampling */
#define X86_FEATURE_BTS		(3*32+13) /* Branch Trace Store */
#define X86_FEATURE_SYSCALL32	(3*32+14) /* "" syscall in ia32 userspace */
#define X86_FEATURE_SYSENTER32	(3*32+15) /* "" sysenter in ia32 userspace */
#define X86_FEATURE_REP_GOOD	(3*32+16) /* rep microcode works well */
#define X86_FEATURE_MFENCE_RDTSC (3*32+17) /* "" Mfence synchronizes RDTSC */
#define X86_FEATURE_LFENCE_RDTSC (3*32+18) /* "" Lfence synchronizes RDTSC */
#define X86_FEATURE_11AP	(3*32+19) /* "" Bad local APIC aka 11AP */
#define X86_FEATURE_NOPL	(3*32+20) /* The NOPL (0F 1F) instructions */
					  /* 21 available, was AMD_C1E */
#define X86_FEATURE_XTOPOLOGY	(3*32+22) /* cpu topology enum extensions */
#define X86_FEATURE_TSC_RELIABLE (3*32+23) /* TSC is known to be reliable */
#define X86_FEATURE_NONSTOP_TSC	(3*32+24) /* TSC does not stop in C states */
#define X86_FEATURE_CLFLUSH_MONITOR (3*32+25) /* "" clflush reqd with monitor */
#define X86_FEATURE_EXTD_APICID	(3*32+26) /* has extended APICID (8 bits) */
#define X86_FEATURE_AMD_DCM     (3*32+27) /* multi-node processor */
#define X86_FEATURE_APERFMPERF	(3*32+28) /* APERFMPERF */

/* Intel-defined CPU features, CPUID level 0x00000001 (ecx), word 4 */
#define X86_FEATURE_XMM3	(4*32+ 0) /* "pni" SSE-3 */
#define X86_FEATURE_PCLMULQDQ	(4*32+ 1) /* PCLMULQDQ instruction */
#define X86_FEATURE_DTES64	(4*32+ 2) /* 64-bit Debug Store */
#define X86_FEATURE_MWAIT	(4*32+ 3) /* "monitor" Monitor/Mwait support */
#define X86_FEATURE_DSCPL	(4*32+ 4) /* "ds_cpl" CPL Qual. Debug Store */
#define X86_FEATURE_VMX		(4*32+ 5) /* Hardware virtualization */
#define X86_FEATURE_SMX		(4*32+ 6) /* Safer mode */
#define X86_FEATURE_EST		(4*32+ 7) /* Enhanced SpeedStep */
#define X86_FEATURE_TM2		(4*32+ 8) /* Thermal Monitor 2 */
#define X86_FEATURE_SSSE3	(4*32+ 9) /* Supplemental SSE-3 */
#define X86_FEATURE_CID		(4*32+10) /* Context ID */
#define X86_FEATURE_FMA		(4*32+12) /* Fused multiply-add */
#define X86_FEATURE_CX16	(4*32+13) /* CMPXCHG16B */
#define X86_FEATURE_XTPR	(4*32+14) /* Send Task Priority Messages */
#define X86_FEATURE_PDCM	(4*32+15) /* Performance Capabilities */
#define X86_FEATURE_DCA		(4*32+18) /* Direct Cache Access */
#define X86_FEATURE_XMM4_1	(4*32+19) /* "sse4_1" SSE-4.1 */
#define X86_FEATURE_XMM4_2	(4*32+20) /* "sse4_2" SSE-4.2 */
#define X86_FEATURE_X2APIC	(4*32+21) /* x2APIC */
#define X86_FEATURE_MOVBE	(4*32+22) /* MOVBE instruction */
#define X86_FEATURE_POPCNT      (4*32+23) /* POPCNT instruction */
#define X86_FEATURE_AES		(4*32+25) /* AES instructions */
#define X86_FEATURE_XSAVE	(4*32+26) /* XSAVE/XRSTOR/XSETBV/XGETBV */
#define X86_FEATURE_OSXSAVE	(4*32+27) /* "" XSAVE enabled in the OS */
#define X86_FEATURE_AVX		(4*32+28) /* Advanced Vector Extensions */
#define X86_FEATURE_F16C	(4*32+29) /* 16-bit fp conversions */
#define X86_FEATURE_RDRND	(4*32+30) /* The RDRAND instruction */
#define X86_FEATURE_HYPERVISOR	(4*32+31) /* Running on a hypervisor */

/* VIA/Cyrix/Centaur-defined CPU features, CPUID level 0xC0000001, word 5 */
#define X86_FEATURE_XSTORE	(5*32+ 2) /* "rng" RNG present (xstore) */
#define X86_FEATURE_XSTORE_EN	(5*32+ 3) /* "rng_en" RNG enabled */
#define X86_FEATURE_XCRYPT	(5*32+ 6) /* "ace" on-CPU crypto (xcrypt) */
#define X86_FEATURE_XCRYPT_EN	(5*32+ 7) /* "ace_en" on-CPU crypto enabled */
#define X86_FEATURE_ACE2	(5*32+ 8) /* Advanced Cryptography Engine v2 */
#define X86_FEATURE_ACE2_EN	(5*32+ 9) /* ACE v2 enabled */
#define X86_FEATURE_PHE		(5*32+10) /* PadLock Hash Engine */
#define X86_FEATURE_PHE_EN	(5*32+11) /* PHE enabled */
#define X86_FEATURE_PMM		(5*32+12) /* PadLock Montgomery Multiplier */
#define X86_FEATURE_PMM_EN	(5*32+13) /* PMM enabled */

/* More extended AMD flags: CPUID level 0x80000001, ecx, word 6 */
#define X86_FEATURE_LAHF_LM	(6*32+ 0) /* LAHF/SAHF in long mode */
#define X86_FEATURE_CMP_LEGACY	(6*32+ 1) /* If yes HyperThreading not valid */
#define X86_FEATURE_SVM		(6*32+ 2) /* Secure virtual machine */
#define X86_FEATURE_EXTAPIC	(6*32+ 3) /* Extended APIC space */
#define X86_FEATURE_CR8_LEGACY	(6*32+ 4) /* CR8 in 32-bit mode */
#define X86_FEATURE_ABM		(6*32+ 5) /* Advanced bit manipulation */
#define X86_FEATURE_SSE4A	(6*32+ 6) /* SSE-4A */
#define X86_FEATURE_MISALIGNSSE (6*32+ 7) /* Misaligned SSE mode */
#define X86_FEATURE_3DNOWPREFETCH (6*32+ 8) /* 3DNow prefetch instructions */
#define X86_FEATURE_OSVW	(6*32+ 9) /* OS Visible Workaround */
#define X86_FEATURE_IBS		(6*32+10) /* Instruction Based Sampling */
#define X86_FEATURE_XOP		(6*32+11) /* extended AVX instructions */
#define X86_FEATURE_SKINIT	(6*32+12) /* SKINIT/STGI instructions */
#define X86_FEATURE_WDT		(6*32+13) /* Watchdog timer */
#define X86_FEATURE_LWP		(6*32+15) /* Light Weight Profiling */
#define X86_FEATURE_FMA4	(6*32+16) /* 4 operands MAC instructions */
#define X86_FEATURE_NODEID_MSR	(6*32+19) /* NodeId MSR */
#define X86_FEATURE_TBM		(6*32+21) /* trailing bit manipulations */
#define X86_FEATURE_TOPOEXT	(6*32+22) /* topology extensions CPUID leafs */

/*
 * Auxiliary flags: Linux defined - For features scattered in various
 * CPUID levels like 0x6, 0xA etc, word 7
 */
#define X86_FEATURE_IDA		(7*32+ 0) /* Intel Dynamic Acceleration */
#define X86_FEATURE_ARAT	(7*32+ 1) /* Always Running APIC Timer */
#define X86_FEATURE_CPB		(7*32+ 2) /* AMD Core Performance Boost */
#define X86_FEATURE_EPB		(7*32+ 3) /* IA32_ENERGY_PERF_BIAS support */
#define X86_FEATURE_XSAVEOPT	(7*32+ 4) /* Optimized Xsave */
#define X86_FEATURE_PLN		(7*32+ 5) /* Intel Power Limit Notification */
#define X86_FEATURE_PTS		(7*32+ 6) /* Intel Package Thermal Status */
#define X86_FEATURE_DTS		(7*32+ 7) /* Digital Thermal Sensor */

/* Virtualization flags: Linux defined, word 8 */
#define X86_FEATURE_TPR_SHADOW  (8*32+ 0) /* Intel TPR Shadow */
#define X86_FEATURE_VNMI        (8*32+ 1) /* Intel Virtual NMI */
#define X86_FEATURE_FLEXPRIORITY (8*32+ 2) /* Intel FlexPriority */
#define X86_FEATURE_EPT         (8*32+ 3) /* Intel Extended Page Table */
#define X86_FEATURE_VPID        (8*32+ 4) /* Intel Virtual Processor ID */
#define X86_FEATURE_NPT		(8*32+ 5) /* AMD Nested Page Table support */
#define X86_FEATURE_LBRV	(8*32+ 6) /* AMD LBR Virtualization support */
#define X86_FEATURE_SVML	(8*32+ 7) /* "svm_lock" AMD SVM locking MSR */
#define X86_FEATURE_NRIPS	(8*32+ 8) /* "nrip_save" AMD SVM next_rip save */
#define X86_FEATURE_TSCRATEMSR  (8*32+ 9) /* "tsc_scale" AMD TSC scaling support */
#define X86_FEATURE_VMCBCLEAN   (8*32+10) /* "vmcb_clean" AMD VMCB clean bits support */
#define X86_FEATURE_FLUSHBYASID (8*32+11) /* AMD flush-by-ASID support */
#define X86_FEATURE_DECODEASSISTS (8*32+12) /* AMD Decode Assists support */
#define X86_FEATURE_PAUSEFILTER (8*32+13) /* AMD filtered pause intercept */
#define X86_FEATURE_PFTHRESHOLD (8*32+14) /* AMD pause filter threshold */


/* Intel-defined CPU features, CPUID level 0x00000007:0 (ebx), word 9 */
#define X86_FEATURE_FSGSBASE	(9*32+ 0) /* {RD/WR}{FS/GS}BASE instructions*/

#if defined(__KERNEL__) && !defined(__ASSEMBLY__)

#include "asm/asm.h"
#include "linux/bitops.h"

extern const char * const x86_cap_flags[NCAPINTS*32];
extern const char * const x86_power_flags[32];

#define test_cpu_cap(c, bit)						\
	 test_bit(bit, (unsigned long *)((c)->x86_capability))

#define cpu_has(c, bit)							\
	(__builtin_constant_p(bit) &&					\
	 ( (((bit)>>5)==0 && (1UL<<((bit)&31) & REQUIRED_MASK0)) ||	\
	   (((bit)>>5)==1 && (1UL<<((bit)&31) & REQUIRED_MASK1)) ||	\
	   (((bit)>>5)==2 && (1UL<<((bit)&31) & REQUIRED_MASK2)) ||	\
	   (((bit)>>5)==3 && (1UL<<((bit)&31) & REQUIRED_MASK3)) ||	\
	   (((bit)>>5)==4 && (1UL<<((bit)&31) & REQUIRED_MASK4)) ||	\
	   (((bit)>>5)==5 && (1UL<<((bit)&31) & REQUIRED_MASK5)) ||	\
	   (((bit)>>5)==6 && (1UL<<((bit)&31) & REQUIRED_MASK6)) ||	\
	   (((bit)>>5)==7 && (1UL<<((bit)&31) & REQUIRED_MASK7)) ||	\
	   (((bit)>>5)==8 && (1UL<<((bit)&31) & REQUIRED_MASK8)) ||	\
	   (((bit)>>5)==9 && (1UL<<((bit)&31) & REQUIRED_MASK9)) )	\
	  ? 1 :								\
	 test_cpu_cap(c, bit))

#define boot_cpu_has(bit)	cpu_has(&boot_cpu_data, bit)

#define set_cpu_cap(c, bit)	set_bit(bit, (unsigned long *)((c)->x86_capability))
#define clear_cpu_cap(c, bit)	clear_bit(bit, (unsigned long *)((c)->x86_capability))
#define setup_clear_cpu_cap(bit) do { \
	clear_cpu_cap(&boot_cpu_data, bit);	\
	set_bit(bit, (unsigned long *)cpu_caps_cleared); \
} while (0)
#define setup_force_cpu_cap(bit) do { \
	set_cpu_cap(&boot_cpu_data, bit);	\
	set_bit(bit, (unsigned long *)cpu_caps_set);	\
} while (0)

#define cpu_has_fpu		boot_cpu_has(X86_FEATURE_FPU)
#define cpu_has_vme		boot_cpu_has(X86_FEATURE_VME)
#define cpu_has_de		boot_cpu_has(X86_FEATURE_DE)
#define cpu_has_pse		boot_cpu_has(X86_FEATURE_PSE)
#define cpu_has_tsc		boot_cpu_has(X86_FEATURE_TSC)
#define cpu_has_pae		boot_cpu_has(X86_FEATURE_PAE)
#define cpu_has_pge		boot_cpu_has(X86_FEATURE_PGE)
#define cpu_has_apic		boot_cpu_has(X86_FEATURE_APIC)
#define cpu_has_sep		boot_cpu_has(X86_FEATURE_SEP)
#define cpu_has_mtrr		boot_cpu_has(X86_FEATURE_MTRR)
#define cpu_has_mmx		boot_cpu_has(X86_FEATURE_MMX)
#define cpu_has_fxsr		boot_cpu_has(X86_FEATURE_FXSR)
#define cpu_has_xmm		boot_cpu_has(X86_FEATURE_XMM)
#define cpu_has_xmm2		boot_cpu_has(X86_FEATURE_XMM2)
#define cpu_has_xmm3		boot_cpu_has(X86_FEATURE_XMM3)
#define cpu_has_aes		boot_cpu_has(X86_FEATURE_AES)
#define cpu_has_ht		boot_cpu_has(X86_FEATURE_HT)
#define cpu_has_mp		boot_cpu_has(X86_FEATURE_MP)
#define cpu_has_nx		boot_cpu_has(X86_FEATURE_NX)
#define cpu_has_k6_mtrr		boot_cpu_has(X86_FEATURE_K6_MTRR)
#define cpu_has_cyrix_arr	boot_cpu_has(X86_FEATURE_CYRIX_ARR)
#define cpu_has_centaur_mcr	boot_cpu_has(X86_FEATURE_CENTAUR_MCR)
#define cpu_has_xstore		boot_cpu_has(X86_FEATURE_XSTORE)
#define cpu_has_xstore_enabled	boot_cpu_has(X86_FEATURE_XSTORE_EN)
#define cpu_has_xcrypt		boot_cpu_has(X86_FEATURE_XCRYPT)
#define cpu_has_xcrypt_enabled	boot_cpu_has(X86_FEATURE_XCRYPT_EN)
#define cpu_has_ace2		boot_cpu_has(X86_FEATURE_ACE2)
#define cpu_has_ace2_enabled	boot_cpu_has(X86_FEATURE_ACE2_EN)
#define cpu_has_phe		boot_cpu_has(X86_FEATURE_PHE)
#define cpu_has_phe_enabled	boot_cpu_has(X86_FEATURE_PHE_EN)
#define cpu_has_pmm		boot_cpu_has(X86_FEATURE_PMM)
#define cpu_has_pmm_enabled	boot_cpu_has(X86_FEATURE_PMM_EN)
#define cpu_has_ds		boot_cpu_has(X86_FEATURE_DS)
#define cpu_has_pebs		boot_cpu_has(X86_FEATURE_PEBS)
#define cpu_has_clflush		boot_cpu_has(X86_FEATURE_CLFLSH)
#define cpu_has_bts		boot_cpu_has(X86_FEATURE_BTS)
#define cpu_has_gbpages		boot_cpu_has(X86_FEATURE_GBPAGES)
#define cpu_has_arch_perfmon	boot_cpu_has(X86_FEATURE_ARCH_PERFMON)
#define cpu_has_pat		boot_cpu_has(X86_FEATURE_PAT)
#define cpu_has_xmm4_1		boot_cpu_has(X86_FEATURE_XMM4_1)
#define cpu_has_xmm4_2		boot_cpu_has(X86_FEATURE_XMM4_2)
#define cpu_has_x2apic		boot_cpu_has(X86_FEATURE_X2APIC)
#define cpu_has_xsave		boot_cpu_has(X86_FEATURE_XSAVE)
#define cpu_has_hypervisor	boot_cpu_has(X86_FEATURE_HYPERVISOR)
#define cpu_has_pclmulqdq	boot_cpu_has(X86_FEATURE_PCLMULQDQ)

#if defined(CONFIG_X86_INVLPG) || defined(CONFIG_X86_64)
# define cpu_has_invlpg		1
#else
# define cpu_has_invlpg		(boot_cpu_data.x86 > 3)
#endif

#ifdef CONFIG_X86_64

#undef  cpu_has_vme
#define cpu_has_vme		0

#undef  cpu_has_pae
#define cpu_has_pae		___BUG___

#undef  cpu_has_mp
#define cpu_has_mp		1

#undef  cpu_has_k6_mtrr
#define cpu_has_k6_mtrr		0

#undef  cpu_has_cyrix_arr
#define cpu_has_cyrix_arr	0

#undef  cpu_has_centaur_mcr
#define cpu_has_centaur_mcr	0

#endif /* CONFIG_X86_64 */

#if __GNUC__ >= 4
/*
 * Static testing of CPU features.  Used the same as boot_cpu_has().
 * These are only valid after alternatives have run, but will statically
 * patch the target code for additional performance.
 *
 */
static __always_inline __pure bool __static_cpu_has(u16 bit)
{
#if __GNUC__ > 4 || __GNUC_MINOR__ >= 5
		asm goto("1: jmp %l[t_no]\n"
			 "2:\n"
			 ".section .altinstructions,\"a\"\n"
			 _ASM_ALIGN "\n"
			 _ASM_PTR "1b\n"
			 _ASM_PTR "0\n" 	/* no replacement */
			 " .word %P0\n"		/* feature bit */
			 " .byte 2b - 1b\n"	/* source len */
			 " .byte 0\n"		/* replacement len */
			 ".previous\n"
			 /* skipping size check since replacement size = 0 */
			 : : "i" (bit) : : t_no);
		return true;
	t_no:
		return false;
#else
		u8 flag;
		/* Open-coded due to __stringify() in ALTERNATIVE() */
		asm volatile("1: movb $0,%0\n"
			     "2:\n"
			     ".section .altinstructions,\"a\"\n"
			     _ASM_ALIGN "\n"
			     _ASM_PTR "1b\n"
			     _ASM_PTR "3f\n"
			     " .word %P1\n"		/* feature bit */
			     " .byte 2b - 1b\n"		/* source len */
			     " .byte 4f - 3f\n"		/* replacement len */
			     ".previous\n"
			     ".section .discard,\"aw\",@progbits\n"
			     " .byte 0xff + (4f-3f) - (2b-1b)\n" /* size check */
			     ".previous\n"
			     ".section .altinstr_replacement,\"ax\"\n"
			     "3: movb $1,%0\n"
			     "4:\n"
			     ".previous\n"
			     : "=qm" (flag) : "i" (bit));
		return flag;
#endif
}

#define static_cpu_has(bit)					\
(								\
	__builtin_constant_p(boot_cpu_has(bit)) ?		\
		boot_cpu_has(bit) :				\
	__builtin_constant_p(bit) ?				\
		__static_cpu_has(bit) :				\
		boot_cpu_has(bit)				\
)
#else
/*
 * gcc 3.x is too stupid to do the static test; fall back to dynamic.
 */
#define static_cpu_has(bit) boot_cpu_has(bit)
#endif

#endif /* defined(__KERNEL__) && !defined(__ASSEMBLY__) */

#endif /* _ASM_X86_CPUFEATURE_H */



[링크 : http://kernelstudy.tistory.com/64]
[링크 : http://www.gentoo-wiki.info/Gentoo:/proc/cpuinfo]

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