linux-kernel - Re: [PATCH v4.4-rc8 1/4] x86/microcode/intel: save_mc_for

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Date:	Mon, 18 Jan 2016 11:10:04 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	tim.gardner@...onical.com, Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>
Cc:	x86@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4.4-rc8 1/4] x86/microcode/intel: save_mc_for_early:
 Squelch frame size warning

On Thu, Jan 07, 2016 at 07:59:56AM -0700, tim.gardner@...onical.com wrote:
> From: Tim Gardner <tim.gardner@...onical.com>
> 
> arch/x86/kernel/cpu/microcode/intel.c: In function 'save_mc_for_early':
> arch/x86/kernel/cpu/microcode/intel.c:516:1: warning: the frame size of 1032 bytes is larger than 1024 bytes [-Wframe-larger-than=]

Ok, so this looks like a 32-bit warning to me.

Hmm, so, on the one hand we do have:

$ git grep CONFIG_FRAME_WARN arch/x86/
arch/x86/configs/i386_defconfig:291:CONFIG_FRAME_WARN=2048

which came in with:

5cb04df8d3f0 ("x86: defconfig updates")

and OTOH:

config FRAME_WARN
        int "Warn for stack frames larger than (needs gcc 4.4)"
        range 0 8192
        default 0 if KASAN
        default 1024 if !64BIT
		^^^^

        default 2048 if 64BIT
        help
          Tell gcc to warn at build time for stack frames larger than this.
          Setting this too low will cause a lot of warnings.
          Setting it to 0 disables the warning.
          Requires gcc 4.4

which is still 1024.

tip guys, maybe it is time to update lib/Kconfig.debug too?

-- 
Regards/Gruss,
    Boris.

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