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authorMarc Zyngier <Marc.Zyngier@arm.com>2013-11-04 10:42:29 (GMT)
committerRussell King <rmk+kernel@arm.linux.org.uk>2013-11-07 00:15:49 (GMT)
commite16b31bf47738f4498d7ce632e12d7d2a6a2492a (patch)
tree32816ec7e20243cdfc3266a07f514e8b002664d3
parent384b38b66947b06999b3e39a596d4f2fb94f77e4 (diff)
downloadlinux-e16b31bf47738f4498d7ce632e12d7d2a6a2492a.tar.xz
ARM: 7876/1: clear Thumb-2 IT state on exception handling
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@arm.com> Cc: stable@vger.kernel.org Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
-rw-r--r--arch/arm/kernel/entry-armv.S1
-rw-r--r--arch/arm/mm/extable.c7
2 files changed, 7 insertions, 1 deletions
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index 9cbe70c..ec3e5cf 100644
--- 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)
diff --git a/arch/arm/mm/extable.c b/arch/arm/mm/extable.c
index 9d28562..312e15e 100644
--- 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;
}