linux-kernel - [PATCH 5/5 -v2] x86, head

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Date:	Sat,  9 Feb 2013 23:08:49 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	"H. Peter Anvin" <hpa@...or.com>
Cc:	X86 ML <x86@...nel.org>, LKML <linux-kernel@...r.kernel.org>,
	Borislav Petkov <bp@...e.de>
Subject: [PATCH 5/5 -v2] x86, head_32: Clear DF much earlier

From: Borislav Petkov <bp@...e.de>

All GCC versions expect the direction flag to be cleared (DF=0) so move
this to the default entry point for each core.

Signed-off-by: Borislav Petkov <bp@...e.de>
---
 arch/x86/kernel/head_32.S | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index 75e96d7e4e5f..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
+
 /*
  * New page tables may be in 4Mbyte page mode and may be using the global pages.
  *
@@ -463,7 +464,6 @@ is486:
 	xorl %eax,%eax			# Clear LDT
 	lldt %ax
 
-	cld			# gcc2 wants the direction flag cleared at all times
 	pushl $0		# fake return address for unwinder
 	jmp *(initial_code)
 
-- 
1.8.1.3.535.ga923c31

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