Re: [PATCH 2/2 v2] x86: make 32-bit "emergency stack" better documented

From: Pavel Machek <pavel@ucw.cz>
To: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>, Oleg Nesterov <oleg@redhat.com>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Alexei Starovoitov <ast@plumgrid.com>,
	Will Drewry <wad@chromium.org>, Kees Cook <keescook@chromium.org>,
	x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2 v2] x86: make 32-bit "emergency stack" better documented
Date: Sat, 14 Mar 2015 17:00:42 +0100	[thread overview]
Message-ID: <20150314160042.GA1338@xo-6d-61-c0.localdomain> (raw)
In-Reply-To: <1425912738-559-2-git-send-email-dvlasenk@redhat.com>

Hi!

>  arch/x86/kernel/asm-offsets_32.c | 2 +-
>  arch/x86/kernel/cpu/common.c     | 3 ++-
>  3 files changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
> index 48a61c1..9e65cf8 100644
> --- a/arch/x86/include/asm/processor.h
> +++ b/arch/x86/include/asm/processor.h
> @@ -276,9 +276,9 @@ struct tss_struct {
>  	unsigned long		io_bitmap[IO_BITMAP_LONGS + 1];
>  
>  	/*
> -	 * .. and then another 0x100 bytes for the emergency kernel stack:
> +	 * and then space for temporary SYSENTER stack:
>  	 */
> -	unsigned long		stack[64];
> +	unsigned long		SYSENTER_stack[64];

Would it make sense to make it unsigned char ...stack[256], like the comment said?

Or is it supposed to be different size on 64bit, and comment was wrong?

									Pavel
-- 
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