[ARM SMP] Clear the exclusive monitor on ARMv6 CPUs on context switch

Ensure that the exclusive monitor is cleared on context switch with
ARMv6 CPUs.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 7 insertions, 0 deletions

diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index 39a6c1b0b9a3..7152bfbee581 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -533,6 +533,13 @@ ENTRY(__switch_to)
         ldr     r3, [r2, #TI_TP_VALUE]
         stmia   ip!, {r4 - sl, fp, sp, lr}      @ Store most regs on stack
         ldr     r6, [r2, #TI_CPU_DOMAIN]!
+#if __LINUX_ARM_ARCH__ >= 6
+#ifdef CONFIG_CPU_MPCORE
+        clrex
+#else
+        strex   r3, r4, [ip]                    @ Clear exclusive monitor
+#endif
+#endif
 #if defined(CONFIG_CPU_XSCALE) && !defined(CONFIG_IWMMXT)
         mra     r4, r5, acc0
         stmia   ip, {r4, r5}