From: "H. Peter Anvin" <hpa@zytor.com>
To: Borislav Petkov <bp@alien8.de>, X86 ML <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>, Borislav Petkov <bp@suse.de>
Subject: Re: [PATCH 5/5] x86, head_32: Remove an old gcc2 fix
Date: Sat, 09 Feb 2013 14:23:36 -0800 [thread overview]
Message-ID: <5116CC68.3090804@zytor.com> (raw)
In-Reply-To: <20130209212342.GA5556@pd.tnic>
On 02/09/2013 01:23 PM, Borislav Petkov wrote:
> On Sat, Feb 09, 2013 at 12:52:01PM -0800, H. Peter Anvin wrote:
>> However... DF should have been cleared long before this...
>
> How about we do this at the beginning of default_entry where we clear
> EFLAGS too:
>
> diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
> index fc56613224c3..8b2a8a824fc6 100644
> --- a/arch/x86/kernel/head_32.S
> +++ b/arch/x86/kernel/head_32.S
> @@ -322,10 +322,11 @@ default_entry:
> * debugger if this code is traced. Best to initialize before switching to
> * protected mode.
> */
> -
> pushl $0
> popfl
>
> + cld # GCC wants DF=0 at all times
> +
The pushfl/popfl sequence clears DF too...
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
next prev parent reply other threads:[~2013-02-09 22:24 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-09 19:52 [PATCH 0/5] x86, head_32: Some cleanups, -v2 Borislav Petkov
2013-02-09 19:52 ` [PATCH 1/5] x86, head_32: Remove i386 pieces Borislav Petkov
2013-02-09 19:52 ` [PATCH 2/5] x86: Detect CPUID support early at boot Borislav Petkov
2013-02-09 19:52 ` [PATCH 3/5] x86, head_32: Remove second CPUID detection from default_entry Borislav Petkov
2013-02-09 19:52 ` [PATCH 4/5] x86, head_32: Give the 6 label a real name Borislav Petkov
2013-02-09 19:52 ` [PATCH 5/5] x86, head_32: Remove an old gcc2 fix Borislav Petkov
2013-02-09 20:51 ` H. Peter Anvin
2013-02-09 20:52 ` H. Peter Anvin
2013-02-09 21:23 ` Borislav Petkov
2013-02-09 22:08 ` [PATCH 5/5 -v2] x86, head_32: Clear DF much earlier Borislav Petkov
2013-02-09 22:23 ` H. Peter Anvin [this message]
2013-02-09 23:13 ` [PATCH 5/5] x86, head_32: Remove an old gcc2 fix Borislav Petkov
2013-02-09 23:16 ` [PATCH 2/5 -v2.1] x86: Detect CPUID support early at boot Borislav Petkov
2013-02-10 4:34 ` H. Peter Anvin
2013-02-10 8:36 ` Borislav Petkov
2013-02-10 15:10 ` H. Peter Anvin
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