ARM: 7661/1: mm: perform explicit branch predictor maintenance when required

The ARM ARM requires branch predictor maintenance if, for a given ASID,
the instructions at a specific virtual address appear to change.

From the kernel's point of view, that means:

	- Changing the kernel's view of memory (e.g. switching to the
	  identity map)
	- ASID rollover (since ASIDs will be re-allocated to new tasks)

This patch adds explicit branch predictor maintenance when either of the
two conditions above are met.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 3 insertions, 1 deletions

diff --git a/arch/arm/mm/context.c b/arch/arm/mm/context.c
index 44d4ee52f3e2..a5a4b2bc42ba 100644
--- a/arch/arm/mm/context.c
+++ b/arch/arm/mm/context.c
@@ -212,8 +212,10 @@ void check_and_switch_context(struct mm_struct *mm, struct task_struct *tsk)
 		atomic64_set(&mm->context.id, asid);
 	}
 
-	if (cpumask_test_and_clear_cpu(cpu, &tlb_flush_pending))
+	if (cpumask_test_and_clear_cpu(cpu, &tlb_flush_pending)) {
+		local_flush_bp_all();
 		local_flush_tlb_all();
+	}
 
 	atomic64_set(&per_cpu(active_asids, cpu), asid);
 	cpumask_set_cpu(cpu, mm_cpumask(mm));