linux-kernel - Re: [PATCH 206/208] x86/fpu: Add CONFIG_X86_DEBUG

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Date:	Tue, 5 May 2015 21:41:16 +0200
From:	Borislav Petkov <bp@...en8.de>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	linux-kernel@...r.kernel.org,
	Andy Lutomirski <luto@...capital.net>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	Fenghua Yu <fenghua.yu@...el.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Oleg Nesterov <oleg@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH 206/208] x86/fpu: Add CONFIG_X86_DEBUG_FPU=y FPU
 debugging code

On Tue, May 05, 2015 at 07:58:30PM +0200, Ingo Molnar wrote:
> There are various internal FPU state debugging checks that never
> trigger in practice, but which are useful for FPU code development.
> 
> Separate these out into CONFIG_X86_DEBUG_FPU=y, and also add a
> couple of new ones.
> 
> The size difference is about 0.5K of code on defconfig:
> 
>    text        data     bss          filename
>    15028906    2578816  1638400      vmlinux
>    15029430    2578816  1638400      vmlinux
> 
> ( Keep this enabled by default until the new FPU code is debugged. )
> 
> Cc: Andy Lutomirski <luto@...capital.net>
> Cc: Borislav Petkov <bp@...en8.de>
> Cc: Dave Hansen <dave.hansen@...ux.intel.com>
> Cc: Fenghua Yu <fenghua.yu@...el.com>
> Cc: H. Peter Anvin <hpa@...or.com>
> Cc: Linus Torvalds <torvalds@...ux-foundation.org>
> Cc: Oleg Nesterov <oleg@...hat.com>
> Cc: Thomas Gleixner <tglx@...utronix.de>
> Signed-off-by: Ingo Molnar <mingo@...nel.org>

...

> diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
> index a4c1b7dbf70e..d2a281bd5f45 100644
> --- a/arch/x86/include/asm/fpu/internal.h
> +++ b/arch/x86/include/asm/fpu/internal.h
> @@ -59,6 +59,15 @@ extern void fpu__clear(struct fpu *fpu);
>  extern void fpu__init_check_bugs(void);
>  extern void fpu__resume_cpu(void);
>  
> +/*
> + * Debugging facility:
> + */
> +#ifdef CONFIG_X86_DEBUG_FPU
> +# define WARN_ON_FPU(x) WARN_ON_ONCE(x)
> +#else
> +# define WARN_ON_FPU(x) ({ 0; })

Shouldn't this be called FPU_WARN_ON() ?

-- 
Regards/Gruss,
    Boris.

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