[ARM] 5487/1: ARM errata: Stale prediction on replaced interworking branch
This patch adds the workaround for the 430973 Cortex-A8 (r1p0..r1p2)
erratum. The BTAC/BTB is now flushed at every context switch.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index d1ebec4..fc81159 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -95,6 +95,9 @@
mov r2, #0
ldr r1, [r1, #MM_CONTEXT_ID] @ get mm->context.id
orr r0, r0, #TTB_FLAGS
+#ifdef CONFIG_ARM_ERRATA_430973
+ mcr p15, 0, r2, c7, c5, 6 @ flush BTAC/BTB
+#endif
mcr p15, 0, r2, c13, c0, 1 @ set reserved context ID
isb
1: mcr p15, 0, r0, c2, c0, 0 @ set TTB 0
@@ -180,6 +183,11 @@
stmia r12, {r0-r5, r7, r9, r11, lr}
bl v7_flush_dcache_all
ldmia r12, {r0-r5, r7, r9, r11, lr}
+#ifdef CONFIG_ARM_ERRATA_430973
+ mrc p15, 0, r10, c1, c0, 1 @ read aux control register
+ orr r10, r10, #(1 << 6) @ set IBE to 1
+ mcr p15, 0, r10, c1, c0, 1 @ write aux control register
+#endif
mov r10, #0
#ifdef HARVARD_CACHE
mcr p15, 0, r10, c7, c5, 0 @ I+BTB cache invalidate