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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: Borislav Petkov <bp@suse.de>
[ Slightly prettified. ]
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Borislav 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: Ingo Molnar <mingo@kernel.org>
hifive-unleashed-5.1
Borislav Petkov 2017-01-18 11:15:37 -08:00 committed by Ingo Molnar
parent a5828ed3d0
commit 78d1b29684
2 changed files with 5 additions and 4 deletions
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2
arch/x86/include/asm/cpufeatures.h
View File

@ -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 */

7
arch/x86/kernel/cpu/common.c
View File

@ -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);