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Commit 78d1b296 authored by Borislav Petkov's avatar Borislav Petkov Committed by Ingo Molnar
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x86/cpu: Add X86_FEATURE_CPUID 



Add a synthetic CPUID flag denoting whether the CPU sports the CPUID
instruction or not. This will come useful later when accomodating
CPUID-less CPUs.

Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
[ Slightly prettified. ]
Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Reviewed-by: default avatarBorislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Whitehead <tedheadster@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/dcb355adae3ab812c79397056a61c212f1a0c7cc.1484705016.git.luto@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent a5828ed3

arch/x86/include/asm/cpufeatures.h

+1 −1
Original line number Diff line number Diff line
@@ -100,7 +100,7 @@ 
#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 */

/* free, was #define X86_FEATURE_CLFLUSH_MONITOR ( 3*32+25) * "" clflush reqd with monitor */

#define X86_FEATURE_CPUID	( 3*32+25) /* CPU has CPUID instruction itself */

#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 */

arch/x86/kernel/cpu/common.c

+4 −3
Original line number Diff line number Diff line
@@ -801,14 +801,12 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c) 
	memset(&c->x86_capability, 0, sizeof c->x86_capability);

	c->extended_cpuid_level = 0;



	if (!have_cpuid_p())

		identify_cpu_without_cpuid(c);



	/* cyrix could have cpuid enabled via c_identify()*/

	if (have_cpuid_p()) {

		cpu_detect(c);

		get_cpu_vendor(c);

		get_cpu_cap(c);

		setup_force_cpu_cap(X86_FEATURE_CPUID);



		if (this_cpu->c_early_init)

			this_cpu->c_early_init(c);
@@ -818,6 +816,9 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c) 


		if (this_cpu->c_bsp_init)

			this_cpu->c_bsp_init(c);

	} else {

		identify_cpu_without_cpuid(c);

		setup_clear_cpu_cap(X86_FEATURE_CPUID);

	}



	setup_force_cpu_cap(X86_FEATURE_ALWAYS);