[ARM] 5416/1: Use unused address in v6_early_abort

The target of the strex instruction to clear the exlusive monitor
is currently the top of the stack.  If the store succeeeds this
corrupts r0 in pt_regs.  Use the next stack location instead of
the current one to prevent any chance of corrupting an in-use
address.

Signed-off-by: Seth Forshee <seth.forshee@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/mm/abort-ev6.S b/arch/arm/mm/abort-ev6.S
index 8a7f65b..94077fb 100644 (file)
--- a/arch/arm/mm/abort-ev6.S
+++ b/arch/arm/mm/abort-ev6.S
@@ -23,7 +23,8 @@ ENTRY(v6_early_abort)
 #ifdef CONFIG_CPU_32v6K
        clrex
 #else
-       strex   r0, r1, [sp]                    @ Clear the exclusive monitor
+       sub     r1, sp, #4                      @ Get unused stack location
+       strex   r0, r1, [r1]                    @ Clear the exclusive monitor
 #endif
        mrc     p15, 0, r1, c5, c0, 0           @ get FSR
        mrc     p15, 0, r0, c6, c0, 0           @ get FAR