ARM: 7757/1: mm: don't flush icache in switch_mm with hardware broadcasting
When scheduling an mm on a CPU where it hasn't previously been used, we
flush the icache on that CPU so that any code loaded previously on
a different core can be safely executed.
For cores with hardware broadcasting of cache maintenance operations,
this is clearly unnecessary, since the inner-shareable invalidation in
__sync_icache_dcache will affect all CPUs.
This patch conditionalises the icache flush in switch_mm based on
cache_ops_need_broadcast().
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Albin Tonnerre <albin.tonnerre@arm.com>
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/include/asm/mmu_context.h b/arch/arm/include/asm/mmu_context.h
index a7b85e0..2a45c33 100644
--- a/arch/arm/include/asm/mmu_context.h
+++ b/arch/arm/include/asm/mmu_context.h
@@ -18,6 +18,7 @@
#include <asm/cacheflush.h>
#include <asm/cachetype.h>
#include <asm/proc-fns.h>
+#include <asm/smp_plat.h>
#include <asm-generic/mm_hooks.h>
void __check_vmalloc_seq(struct mm_struct *mm);
@@ -98,12 +99,16 @@
#ifdef CONFIG_MMU
unsigned int cpu = smp_processor_id();
-#ifdef CONFIG_SMP
- /* check for possible thread migration */
- if (!cpumask_empty(mm_cpumask(next)) &&
+ /*
+ * __sync_icache_dcache doesn't broadcast the I-cache invalidation,
+ * so check for possible thread migration and invalidate the I-cache
+ * if we're new to this CPU.
+ */
+ if (cache_ops_need_broadcast() &&
+ !cpumask_empty(mm_cpumask(next)) &&
!cpumask_test_cpu(cpu, mm_cpumask(next)))
__flush_icache_all();
-#endif
+
if (!cpumask_test_and_set_cpu(cpu, mm_cpumask(next)) || prev != next) {
check_and_switch_context(next, tsk);
if (cache_is_vivt())