@@ -1281,7 +1281,7 @@ config ARM_ERRATA_743622
config ARM_ERRATA_751472
bool "ARM errata: Interrupted ICIALLUIS may prevent completion of broadcasted operation"
- depends on CPU_V7 && SMP
+ depends on CPU_V7
help
This option enables the workaround for the 751472 Cortex-A9 (prior
to r3p0) erratum. An interrupted ICIALLUIS operation may prevent the
@@ -363,11 +363,13 @@ __v7_setup:
orreq r10, r10, #1 << 6 @ set bit #6
mcreq p15, 0, r10, c15, c0, 1 @ write diagnostic register
#endif
-#ifdef CONFIG_ARM_ERRATA_751472
- cmp r6, #0x30 @ present prior to r3p0
+#if defined(CONFIG_ARM_ERRATA_751472) && defined(CONFIG_SMP)
+ ALT_SMP(cmp r6, #0x30) @ present prior to r3p0
+ ALT_UP_B(1f)
mrclt p15, 0, r10, c15, c0, 1 @ read diagnostic register
orrlt r10, r10, #1 << 11 @ set bit #11
mcrlt p15, 0, r10, c15, c0, 1 @ write diagnostic register
+1:
#endif
3: mov r10, #0
Activation conditions for a workaround should not be encoded in the workaround's direct dependencies if this makes otherwise reasonable configuration choices impossible. This patches uses the SMP/UP patching facilities instead to compile out the workaround if the configuration means that it is definitely not needed. This means that configs for buggy silicon can simply select ARM_ERRATA_751472, without preventing a UP kernel from being built or duplicatiing knowledge about when to activate the workaround. This seems the correct why to do things, because the erratum is a property of the silicon, irrespective of what the kernel config happens to be. Signed-off-by: Dave Martin <dave.martin@linaro.org> --- Changes since v1: v2: Fix incorrect use of ALT_SMP()/ALT_UP_B(): they must be used in the correct order, otherwise the fixup will reference the wrong ALT_SMP() block and get applied in the wrong place. Make the whole erratum workaround #ifdef CONFIG_SMP so that we don't leave some dead code and an unnecessary branch in the image when building a uniprocessor kernel. arch/arm/Kconfig | 2 +- arch/arm/mm/proc-v7.S | 6 ++++-- 2 files changed, 5 insertions(+), 3 deletions(-)