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SubjectRe: [PATCH] perf/x86/intel/pt: Use boot_cpu_has() because it's there
On Wed, Apr 06, 2016 at 05:35:07PM +0300, Alexander Shishkin wrote:
> At the moment, initialization path is using test_cpu_cap(&boot_cpu_data),
> to detect PT, which is just open coding boot_cpu_has(). Use the latter
> instead.
>
> Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> ---
> arch/x86/events/intel/pt.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/events/intel/pt.c b/arch/x86/events/intel/pt.c
> index 32b613e863..7c7f09a8fe 100644
> --- a/arch/x86/events/intel/pt.c
> +++ b/arch/x86/events/intel/pt.c
> @@ -1159,7 +1159,7 @@ static __init int pt_init(void)
>
> BUILD_BUG_ON(sizeof(struct topa) > PAGE_SIZE);
>
> - if (!test_cpu_cap(&boot_cpu_data, X86_FEATURE_INTEL_PT))
> + if (!boot_cpu_has(X86_FEATURE_INTEL_PT))
> return -ENODEV;
>
> get_online_cpus();
> --

Acked-by: Borislav Petkov <bp@suse.de>

Btw, there's another wonderful gem in the tree:

arch/x86/kernel/cpu/cyrix.c:201: if (test_cpu_cap(c, 1*32+24)) {

Jeez, and a naked number at that which is not even a define in
arch/x86/include/asm/cpufeatures.h

Ah, I need to look at the whole thing:

/* Cyrix used bit 24 in extended (AMD) CPUID for Cyrix MMX extensions */
if (test_cpu_cap(c, 1*32+24)) {
clear_cpu_cap(c, 1*32+24);
set_cpu_cap(c, X86_FEATURE_CXMMX);
}

So it is actually a correction for "smart" hw.

--
Regards/Gruss,
Boris.

ECO tip #101: Trim your mails when you reply.

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