ARM: 7823/1: errata: workaround Cortex-A15 erratum 773022
On Cortex-A15 CPUs up to and including r0p4, in certain rare sequences
of code, the loop buffer may deliver incorrect instructions. This
workaround disables the loop buffer to avoid the erratum.
Signed-off-by: Will Deacon <will.deacon@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 5c6d5a3..e7d45d5 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -329,7 +329,19 @@
1:
#endif
-3: mov r10, #0
+ /* Cortex-A15 Errata */
+3: ldr r10, =0x00000c0f @ Cortex-A15 primary part number
+ teq r0, r10
+ bne 4f
+
+#ifdef CONFIG_ARM_ERRATA_773022
+ cmp r6, #0x4 @ only present up to r0p4
+ mrcle p15, 0, r10, c1, c0, 1 @ read aux control register
+ orrle r10, r10, #1 << 1 @ disable loop buffer
+ mcrle p15, 0, r10, c1, c0, 1 @ write aux control register
+#endif
+
+4: mov r10, #0
mcr p15, 0, r10, c7, c5, 0 @ I+BTB cache invalidate
dsb
#ifdef CONFIG_MMU