This is a note to let you know that I've just added the patch titled
ARM: 7876/1: clear Thumb-2 IT state on exception handling
to the 3.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm-7876-1-clear-thumb-2-it-state-on-exception-handling.patch
and it can be found in the queue-3.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From e16b31bf47738f4498d7ce632e12d7d2a6a2492a Mon Sep 17 00:00:00 2001
From: Marc Zyngier <Marc.Zyngier@xxxxxxx>
Date: Mon, 4 Nov 2013 11:42:29 +0100
Subject: ARM: 7876/1: clear Thumb-2 IT state on exception handling
From: Marc Zyngier <Marc.Zyngier@xxxxxxx>
commit e16b31bf47738f4498d7ce632e12d7d2a6a2492a upstream.
The exception handling code fails to clear the IT state, potentially
leading to incorrect execution of the fixup if the size of the IT
block is more than one.
Let fixup_exception do the IT sanitizing if a fixup has been found,
and restore CPSR from the stack when returning from a data abort.
Cc: Will Deacon <will.deacon@xxxxxxx>
Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm/kernel/entry-armv.S | 1 +
arch/arm/mm/extable.c | 7 ++++++-
2 files changed, 7 insertions(+), 1 deletion(-)
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -192,6 +192,7 @@ __dabt_svc:
svc_entry
mov r2, sp
dabt_helper
+ THUMB( ldr r5, [sp, #S_PSR] ) @ potentially updated CPSR
svc_exit r5 @ return from exception
UNWIND(.fnend )
ENDPROC(__dabt_svc)
--- a/arch/arm/mm/extable.c
+++ b/arch/arm/mm/extable.c
@@ -9,8 +9,13 @@ int fixup_exception(struct pt_regs *regs
const struct exception_table_entry *fixup;
fixup = search_exception_tables(instruction_pointer(regs));
- if (fixup)
+ if (fixup) {
regs->ARM_pc = fixup->fixup;
+#ifdef CONFIG_THUMB2_KERNEL
+ /* Clear the IT state to avoid nasty surprises in the fixup */
+ regs->ARM_cpsr &= ~PSR_IT_MASK;
+#endif
+ }
return fixup != NULL;
}
Patches currently in stable-queue which might be from Marc.Zyngier@xxxxxxx are
queue-3.12/arm-7876-1-clear-thumb-2-it-state-on-exception-handling.patch
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