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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2011-02-24 10:47:32 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2011-03-02 14:56:48 +1100
commitf342552b917a18a7a1fa2c10625df85fac828c36 (patch)
tree236fc598d5c4342bd69c0098547ad6df51557990 /arch/powerpc
parentdd9c1549edef02290edced639f67b54a25abbe0e (diff)
downloadlinux-2.6.38-lt-ux500-f342552b917a18a7a1fa2c10625df85fac828c36.tar.gz
powerpc/mm: Make hpte_need_flush() safe for preemption
hpte_need_flush() might be called outside of a preempt section when manipulating the kernel page tables, so we need to use the appopriate variants of per-cpu variable accesses. There should be no risk of being in the middle of a batch and a context switch will flush any pending batch. [Patch extracted from a larger patch in Peter's preemptible mmu_gather series] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/mm/tlb_hash64.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/powerpc/mm/tlb_hash64.c b/arch/powerpc/mm/tlb_hash64.c
index 1ec06576f61..c14d09f614f 100644
--- a/arch/powerpc/mm/tlb_hash64.c
+++ b/arch/powerpc/mm/tlb_hash64.c
@@ -38,13 +38,11 @@ DEFINE_PER_CPU(struct ppc64_tlb_batch, ppc64_tlb_batch);
* neesd to be flushed. This function will either perform the flush
* immediately or will batch it up if the current CPU has an active
* batch on it.
- *
- * Must be called from within some kind of spinlock/non-preempt region...
*/
void hpte_need_flush(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, unsigned long pte, int huge)
{
- struct ppc64_tlb_batch *batch = &__get_cpu_var(ppc64_tlb_batch);
+ struct ppc64_tlb_batch *batch = &get_cpu_var(ppc64_tlb_batch);
unsigned long vsid, vaddr;
unsigned int psize;
int ssize;
@@ -99,6 +97,7 @@ void hpte_need_flush(struct mm_struct *mm, unsigned long addr,
*/
if (!batch->active) {
flush_hash_page(vaddr, rpte, psize, ssize, 0);
+ put_cpu_var(ppc64_tlb_batch);
return;
}
@@ -127,6 +126,7 @@ void hpte_need_flush(struct mm_struct *mm, unsigned long addr,
batch->index = ++i;
if (i >= PPC64_TLB_BATCH_NR)
__flush_tlb_pending(batch);
+ put_cpu_var(ppc64_tlb_batch);
}
/*