From 3daa48d1d9bc44baa079d65e72ef2e3f1139ac03 Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Wed, 24 Jul 2013 13:53:45 -0700 Subject: ARC: [ASID] get_new_mmu_context() to conditionally allocate new ASID ASID allocation changes/1 This patch does 2 things: (1) get_new_mmu_context() NOW moves mm->ASID to a new value ONLY if it was from a prev allocation cycle/generation OR if mm had no ASID allocated (vs. before would unconditionally moving to a new ASID) Callers desiring unconditional update of ASID, e.g.local_flush_tlb_mm() (for parent's address space invalidation at fork) need to first force the parent to an unallocated ASID. (2) get_new_mmu_context() always sets the MMU PID reg with unchanged/new ASID value. The gains are: - consolidation of all asid alloc logic into get_new_mmu_context() - avoiding code duplication in switch_mm() for PID reg setting - Enables future change to fold activate_mm() into switch_mm() Signed-off-by: Vineet Gupta --- arch/arc/mm/tlb.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) (limited to 'arch/arc/mm') diff --git a/arch/arc/mm/tlb.c b/arch/arc/mm/tlb.c index a4ad68c4b50d..b5c5e0aa0aaa 100644 --- a/arch/arc/mm/tlb.c +++ b/arch/arc/mm/tlb.c @@ -258,13 +258,14 @@ noinline void local_flush_tlb_mm(struct mm_struct *mm) return; /* - * Workaround for Android weirdism: - * A binder VMA could end up in a task such that vma->mm != tsk->mm - * old code would cause h/w - s/w ASID to get out of sync + * - Move to a new ASID, but only if the mm is still wired in + * (Android Binder ended up calling this for vma->mm != tsk->mm, + * causing h/w - s/w ASID to get out of sync) + * - Also get_new_mmu_context() new implementation allocates a new + * ASID only if it is not allocated already - so unallocate first */ - if (current->mm != mm) - destroy_context(mm); - else + destroy_context(mm); + if (current->mm == mm) get_new_mmu_context(mm); } -- cgit v1.2.3