Commit 89c7e4b8 authored by Will Deacon's avatar Will Deacon Committed by Russell King
Browse files

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: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 862c588f

arch/arm/kernel/smp.c

+1 −0
Original line number Diff line number Diff line
@@ -285,6 +285,7 @@ asmlinkage void __cpuinit secondary_start_kernel(void) 
	 * switch away from it before attempting any exclusive accesses.

	 */

	cpu_switch_mm(mm->pgd, mm);

	local_flush_bp_all();

	enter_lazy_tlb(mm, current);

	local_flush_tlb_all();

arch/arm/kernel/suspend.c

+1 −0
Original line number Diff line number Diff line
@@ -68,6 +68,7 @@ int cpu_suspend(unsigned long arg, int (*fn)(unsigned long)) 
	ret = __cpu_suspend(arg, fn);

	if (ret == 0) {

		cpu_switch_mm(mm->pgd, mm);

		local_flush_bp_all();

		local_flush_tlb_all();

	}

arch/arm/mm/context.c

+3 −1
Original line number Diff line number Diff line
@@ -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));

arch/arm/mm/idmap.c

+1 −0
Original line number Diff line number Diff line
@@ -141,6 +141,7 @@ void setup_mm_for_reboot(void) 
{

	/* Switch to the identity mapping. */

	cpu_switch_mm(idmap_pgd, &init_mm);

	local_flush_bp_all();



#ifdef CONFIG_CPU_HAS_ASID

	/*

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