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authorVineet Gupta <vgupta@synopsys.com>2013-07-24 13:53:45 -0700
committerVineet Gupta <vgupta@synopsys.com>2013-08-30 21:42:18 +0530
commit3daa48d1d9bc44baa079d65e72ef2e3f1139ac03 (patch)
tree2e659049c5ee5584c789cc42643aa653cfdb307d /arch/arc/mm
parent5bd87adf9b2ae5fa1bb469c68029b4eec06d6e03 (diff)
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 <vgupta@synopsys.com>
Diffstat (limited to 'arch/arc/mm')
-rw-r--r--arch/arc/mm/tlb.c13
1 files changed, 7 insertions, 6 deletions
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);
}