From mboxrd@z Thu Jan 1 00:00:00 1970 From: will.deacon@arm.com (Will Deacon) Date: Mon, 25 Feb 2013 15:21:28 +0000 Subject: [PATCH 2/2] ARM: mm: perform explicit branch predictor maintenance when required In-Reply-To: <1361805688-8886-1-git-send-email-will.deacon@arm.com> References: <1361805688-8886-1-git-send-email-will.deacon@arm.com> Message-ID: <1361805688-8886-2-git-send-email-will.deacon@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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. Cc: Signed-off-by: Will Deacon --- arch/arm/kernel/smp.c | 1 + arch/arm/kernel/suspend.c | 1 + arch/arm/mm/context.c | 4 +++- arch/arm/mm/idmap.c | 1 + 4 files changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 5f73f70..6f00f3c 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -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(); diff --git a/arch/arm/kernel/suspend.c b/arch/arm/kernel/suspend.c index 358bca3..c59c97e 100644 --- a/arch/arm/kernel/suspend.c +++ b/arch/arm/kernel/suspend.c @@ -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(); } diff --git a/arch/arm/mm/context.c b/arch/arm/mm/context.c index 44d4ee5..a5a4b2bc 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)); diff --git a/arch/arm/mm/idmap.c b/arch/arm/mm/idmap.c index 2dffc01..5ee505c 100644 --- a/arch/arm/mm/idmap.c +++ b/arch/arm/mm/idmap.c @@ -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 /* -- 1.8.0