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From: Stuart Yoder <stuart.yoder@freescale.com>
To: <benh@kernel.crashing.org>
Cc: sfr@canb.auug.org.au, Stuart Yoder <stuart.yoder@freescale.com>,
	paulus@samba.org, linuxppc-dev@lists.ozlabs.org, agraf@suse.de
Subject: [PATCH] powerpc: set stack limit properly in crit_transfer_to_handler
Date: Mon, 16 Jul 2012 14:06:48 -0500	[thread overview]
Message-ID: <1342465608-20596-1-git-send-email-stuart.yoder@freescale.com> (raw)

From: Stuart Yoder <stuart.yoder@freescale.com>

without setting the stack limit like this there is the possibility
of stack overflow which corrupts the thread info but
is not detected by stack overflow detection

Signed-off-by: Stuart Yoder <stuart.yoder@freescale.com>
---
 arch/powerpc/kernel/entry_32.S |   12 ++++++++++--
 1 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 5207d5a..ead5016 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -89,10 +89,14 @@ crit_transfer_to_handler:
 	mfspr	r0,SPRN_SRR1
 	stw	r0,_SRR1(r11)
 
+	/* set the stack limit to the current stack
+	 * and set the limit to protect the thread_info
+	 * struct
+	 */
 	mfspr	r8,SPRN_SPRG_THREAD
 	lwz	r0,KSP_LIMIT(r8)
 	stw	r0,SAVED_KSP_LIMIT(r11)
-	CURRENT_THREAD_INFO(r0, r1)
+	rlwimi	r0,r1,0,0,(31-THREAD_SHIFT)
 	stw	r0,KSP_LIMIT(r8)
 	/* fall through */
 #endif
@@ -109,10 +113,14 @@ crit_transfer_to_handler:
 	mfspr	r0,SPRN_SRR1
 	stw	r0,crit_srr1@l(0)
 
+	/* set the stack limit to the current stack
+	 * and set the limit to protect the thread_info
+	 * struct
+	 */
 	mfspr	r8,SPRN_SPRG_THREAD
 	lwz	r0,KSP_LIMIT(r8)
 	stw	r0,saved_ksp_limit@l(0)
-	CURRENT_THREAD_INFO(r0, r1)
+	rlwimi	r0,r1,0,0,(31-THREAD_SHIFT)
 	stw	r0,KSP_LIMIT(r8)
 	/* fall through */
 #endif
-- 
1.7.3.4

             reply	other threads:[~2012-07-16 19:07 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-07-16 19:06 Stuart Yoder [this message]
2012-07-16 20:36 ` [PATCH] powerpc: set stack limit properly in crit_transfer_to_handler Kumar Gala
2012-07-16 21:20   ` Yoder Stuart-B08248

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