linux-kernel - Re: [PATCH 3/4] x86/cpufeature: Remove unused and seldomly used cpu_has

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Message-ID: <alpine.DEB.2.11.1512051938260.3595@nanos>
Date:	Sat, 5 Dec 2015 19:50:11 +0100 (CET)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Borislav Petkov <bp@...en8.de>
cc:	X86 ML <x86@...nel.org>, LKML <linux-kernel@...r.kernel.org>,
	David Sterba <dsterba@...e.com>,
	Herbert Xu <herbert@...dor.apana.org.au>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Matt Mackall <mpm@...enic.com>, Chris Mason <clm@...com>,
	Josef Bacik <jbacik@...com>
Subject: Re: [PATCH 3/4] x86/cpufeature: Remove unused and seldomly used
 cpu_has_xx macros

On Tue, 1 Dec 2015, Borislav Petkov wrote:
>  #if __GNUC__ >= 4
>  extern void warn_pre_alternatives(void);
> diff --git a/arch/x86/include/asm/xor_32.h b/arch/x86/include/asm/xor_32.h
> index 5a08bc8bff33..ccca77dad474 100644
> --- a/arch/x86/include/asm/xor_32.h
> +++ b/arch/x86/include/asm/xor_32.h
> @@ -553,7 +553,7 @@ do {							\
>  	if (cpu_has_xmm) {				\
>  		xor_speed(&xor_block_pIII_sse);		\
>  		xor_speed(&xor_block_sse_pf64);		\
> -	} else if (cpu_has_mmx) {			\
> +	} else if (static_cpu_has_safe(X86_FEATURE_MMX)) { \

This one can be boot_cpu_has. It's only used in crypto init for
testing the fastest xor algo.

> diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
> index 3b533cf37c74..8f2ef910c7bf 100644
> --- a/arch/x86/kernel/cpu/mtrr/generic.c
> +++ b/arch/x86/kernel/cpu/mtrr/generic.c
> @@ -349,7 +349,7 @@ static void get_fixed_ranges(mtrr_type *frs)
>  
>  void mtrr_save_fixed_ranges(void *info)
>  {
> -	if (cpu_has_mtrr)
> +	if (static_cpu_has_safe(X86_FEATURE_MTRR))
>  		get_fixed_ranges(mtrr_state.fixed_ranges);

This one is not really hotpath either. Its called from cpu_up and from
hibernation code.

Thanks,

	tglx
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