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From: "H. Peter Anvin" <hpa@linux.intel.com>
To: linux-kernel@vger.kernel.org
Cc: vgoyal@redhat.com, hbabu@us.ibm.com, kexec@lists.infradead.org,
	ying.huang@intel.com, mingo@elte.hu, tglx@linutronix.de,
	ebiederm@xmission.com, sam@ravnborg.org,
	"H. Peter Anvin" <hpa@zytor.com>
Subject: [PATCH 12/14] x86, boot: zero EFLAGS on 32 bits
Date: Thu,  7 May 2009 15:27:00 -0700	[thread overview]
Message-ID: <1241735222-6640-13-git-send-email-hpa@linux.intel.com> (raw)
In-Reply-To: <1241735222-6640-1-git-send-email-hpa@linux.intel.com>

From: H. Peter Anvin <hpa@zytor.com>

The 64-bit code already clears EFLAGS as soon as it has a stack.  This
seems like a reasonable precaution, so do it on 32 bits as well.

[ Impact: extra paranoia ]

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
 arch/x86/boot/compressed/head_32.S |   10 ++++++++--
 1 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/x86/boot/compressed/head_32.S b/arch/x86/boot/compressed/head_32.S
index 47636b3..48c2047 100644
--- a/arch/x86/boot/compressed/head_32.S
+++ b/arch/x86/boot/compressed/head_32.S
@@ -12,9 +12,9 @@
  * the page directory. [According to comments etc elsewhere on a compressed
  * kernel it will end up at 0x1000 + 1Mb I hope so as I assume this. - AC]
  *
- * Page 0 is deliberately kept safe, since System Management Mode code in 
+ * Page 0 is deliberately kept safe, since System Management Mode code in
  * laptops may need to access the BIOS data stored there.  This is also
- * useful for future device drivers that either access the BIOS via VM86 
+ * useful for future device drivers that either access the BIOS via VM86
  * mode.
  */
 
@@ -84,6 +84,12 @@ ENTRY(startup_32)
 	leal boot_stack_end(%ebx), %esp
 
 /*
+ * Zero EFLAGS
+ */
+	pushl $0
+	popfl
+
+/*
  * Copy the compressed kernel to the end of our buffer
  * where decompression in place becomes safe.
  */
-- 
1.6.0.6


WARNING: multiple messages have this Message-ID (diff)
From: "H. Peter Anvin" <hpa@linux.intel.com>
To: linux-kernel@vger.kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>,
	kexec@lists.infradead.org, hbabu@us.ibm.com,
	ebiederm@xmission.com, ying.huang@intel.com, mingo@elte.hu,
	sam@ravnborg.org, tglx@linutronix.de, vgoyal@redhat.com
Subject: [PATCH 12/14] x86, boot: zero EFLAGS on 32 bits
Date: Thu,  7 May 2009 15:27:00 -0700	[thread overview]
Message-ID: <1241735222-6640-13-git-send-email-hpa@linux.intel.com> (raw)
In-Reply-To: <1241735222-6640-1-git-send-email-hpa@linux.intel.com>

From: H. Peter Anvin <hpa@zytor.com>

The 64-bit code already clears EFLAGS as soon as it has a stack.  This
seems like a reasonable precaution, so do it on 32 bits as well.

[ Impact: extra paranoia ]

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
 arch/x86/boot/compressed/head_32.S |   10 ++++++++--
 1 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/x86/boot/compressed/head_32.S b/arch/x86/boot/compressed/head_32.S
index 47636b3..48c2047 100644
--- a/arch/x86/boot/compressed/head_32.S
+++ b/arch/x86/boot/compressed/head_32.S
@@ -12,9 +12,9 @@
  * the page directory. [According to comments etc elsewhere on a compressed
  * kernel it will end up at 0x1000 + 1Mb I hope so as I assume this. - AC]
  *
- * Page 0 is deliberately kept safe, since System Management Mode code in 
+ * Page 0 is deliberately kept safe, since System Management Mode code in
  * laptops may need to access the BIOS data stored there.  This is also
- * useful for future device drivers that either access the BIOS via VM86 
+ * useful for future device drivers that either access the BIOS via VM86
  * mode.
  */
 
@@ -84,6 +84,12 @@ ENTRY(startup_32)
 	leal boot_stack_end(%ebx), %esp
 
 /*
+ * Zero EFLAGS
+ */
+	pushl $0
+	popfl
+
+/*
  * Copy the compressed kernel to the end of our buffer
  * where decompression in place becomes safe.
  */
-- 
1.6.0.6


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  parent reply	other threads:[~2009-05-07 22:32 UTC|newest]

Thread overview: 90+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-07 22:26 [PATCH 00/14] RFC: x86: relocatable kernel changes H. Peter Anvin
2009-05-07 22:26 ` H. Peter Anvin
2009-05-07 22:26 ` [PATCH 01/14] x86, boot: align the .bss section in the decompressor H. Peter Anvin
2009-05-07 22:26   ` H. Peter Anvin
2009-05-08  7:17   ` Sam Ravnborg
2009-05-08  7:17     ` Sam Ravnborg
2009-05-08  8:18     ` Eric Dumazet
2009-05-08  8:18       ` Eric Dumazet
2009-05-08 16:54     ` H. Peter Anvin
2009-05-08 16:54       ` H. Peter Anvin
2009-05-08  7:53   ` Cyrill Gorcunov
2009-05-08  7:53     ` Cyrill Gorcunov
2009-05-08 17:03     ` H. Peter Anvin
2009-05-08 17:03       ` H. Peter Anvin
2009-05-08 17:15       ` Cyrill Gorcunov
2009-05-08 17:15         ` Cyrill Gorcunov
2009-05-08 17:21         ` H. Peter Anvin
2009-05-08 17:21           ` H. Peter Anvin
2009-05-07 22:26 ` [PATCH 02/14] x86, boot: honor CONFIG_PHYSICAL_START when relocatable H. Peter Anvin
2009-05-07 22:26   ` H. Peter Anvin
2009-05-08  7:34   ` Sam Ravnborg
2009-05-08  7:34     ` Sam Ravnborg
2009-05-08 16:58     ` H. Peter Anvin
2009-05-08 16:58       ` H. Peter Anvin
2009-05-07 22:26 ` [PATCH 03/14] x86, config: change defaults PHYSICAL_START and PHYSICAL_ALIGN H. Peter Anvin
2009-05-07 22:26   ` H. Peter Anvin
2009-05-08  7:36   ` Sam Ravnborg
2009-05-08  7:36     ` Sam Ravnborg
2009-05-08  9:47     ` Ingo Molnar
2009-05-08  9:47       ` Ingo Molnar
2009-05-08 17:01     ` H. Peter Anvin
2009-05-08 17:01       ` H. Peter Anvin
2009-05-07 22:26 ` [PATCH 04/14] x86, boot: unify use LOAD_PHYSICAL_ADDR and LOAD_PHYSICAL_ALIGN H. Peter Anvin
2009-05-07 22:26   ` H. Peter Anvin
2009-05-07 22:26 ` [PATCH 05/14] kbuild: allow compressors (gzip, bzip2, lzma) to take multiple inputs H. Peter Anvin
2009-05-07 22:26   ` H. Peter Anvin
2009-05-08  7:42   ` Sam Ravnborg
2009-05-08  7:42     ` Sam Ravnborg
2009-05-08 20:18     ` H. Peter Anvin
2009-05-08 20:18       ` H. Peter Anvin
2009-05-08 20:47       ` Sam Ravnborg
2009-05-08 20:47         ` Sam Ravnborg
2009-05-08 20:49         ` H. Peter Anvin
2009-05-08 20:49           ` H. Peter Anvin
2009-05-08 21:33           ` Sam Ravnborg
2009-05-08 21:33             ` Sam Ravnborg
2009-05-07 22:26 ` [PATCH 06/14] x86: add a Kconfig symbol for when relocations are needed H. Peter Anvin
2009-05-07 22:26   ` H. Peter Anvin
2009-05-07 22:26 ` [PATCH 07/14] x86, boot: simplify arch/x86/boot/compressed/Makefile H. Peter Anvin
2009-05-07 22:26   ` H. Peter Anvin
2009-05-08  7:45   ` Sam Ravnborg
2009-05-08  7:45     ` Sam Ravnborg
2009-05-07 22:26 ` [PATCH 08/14] x86, boot: use BP_scratch in arch/x86/boot/compressed/head_*.S H. Peter Anvin
2009-05-07 22:26   ` H. Peter Anvin
2009-05-07 22:26 ` [PATCH 09/14] x86, boot: add new runtime_address and runtime_size bzImage fields H. Peter Anvin
2009-05-07 22:26   ` H. Peter Anvin
2009-05-08  7:55   ` Sam Ravnborg
2009-05-08  7:55     ` Sam Ravnborg
2009-05-08 21:09     ` H. Peter Anvin
2009-05-08 21:09       ` H. Peter Anvin
2009-05-08 21:35       ` Sam Ravnborg
2009-05-08 21:35         ` Sam Ravnborg
2009-05-07 22:26 ` [PATCH 10/14] x86, doc: document the runtime_start " H. Peter Anvin
2009-05-07 22:26   ` H. Peter Anvin
2009-05-07 22:26 ` [PATCH 11/14] x86, boot: use rep movsq to move kernel on 64 bits H. Peter Anvin
2009-05-07 22:26   ` H. Peter Anvin
2009-05-07 22:27 ` H. Peter Anvin [this message]
2009-05-07 22:27   ` [PATCH 12/14] x86, boot: zero EFLAGS on 32 bits H. Peter Anvin
2009-05-07 22:27 ` [PATCH 13/14] x86: make CONFIG_RELOCATABLE the default H. Peter Anvin
2009-05-07 22:27   ` H. Peter Anvin
2009-05-07 22:27 ` [PATCH 14/14] x86, defconfig: update defconfigs to relocatable H. Peter Anvin
2009-05-07 22:27   ` H. Peter Anvin
2009-05-08  1:23 ` [PATCH 00/14] RFC: x86: relocatable kernel changes Eric W. Biederman
2009-05-08  1:23   ` Eric W. Biederman
2009-05-08  5:31   ` H. Peter Anvin
2009-05-08  5:31     ` H. Peter Anvin
2009-05-08  6:54     ` Eric W. Biederman
2009-05-08  6:54       ` Eric W. Biederman
2009-05-08 18:04       ` H. Peter Anvin
2009-05-08 18:04         ` H. Peter Anvin
2009-05-08 18:47       ` H. Peter Anvin
2009-05-08 18:47         ` H. Peter Anvin
2009-05-11  5:18         ` RFC: x86: relocatable kernel changes (revised spec) H. Peter Anvin
2009-05-11  5:18           ` H. Peter Anvin
2009-05-11 11:54           ` Eric W. Biederman
2009-05-11 11:54             ` Eric W. Biederman
2009-05-11 16:03             ` H. Peter Anvin
2009-05-11 16:03               ` H. Peter Anvin
2009-05-11 17:56             ` RFC: x86: relocatable kernel changes (revised spec v2) H. Peter Anvin
2009-05-11 17:56               ` H. Peter Anvin

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