diff options
| author | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2008-03-31 07:49:27 +1100 |
|---|---|---|
| committer | Paul Mackerras <paulus@samba.org> | 2008-04-03 22:11:11 +1100 |
| commit | b991f05f1326fd9e6212851d0f2099875906dd16 (patch) | |
| tree | 3ed9768f865989ab221bcbfbfb8df930997cb3b6 | |
| parent | ff3da2e0938bae36d10d69c22bce0177b067a9e2 (diff) | |
[POWERPC] Fix deadlock with mmu_hash_lock in hash_page_sync
hash_page_sync() takes and releases the low level mmu hash
lock in order to sync with other processors disposing of page
tables. Because that lock can be needed to service hash misses
triggered by interrupt handlers, taking it must be done with
interrupts off. However, hash_page_sync() appears to be called
with interrupts enabled, thus causing occasional deadlocks.
We fix it by making sure hash_page_sync() masks interrupts while
holding the lock.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
| -rw-r--r-- | arch/powerpc/mm/hash_low_32.S | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/arch/powerpc/mm/hash_low_32.S b/arch/powerpc/mm/hash_low_32.S index 7f830a4888d..e10d76a860d 100644 --- a/arch/powerpc/mm/hash_low_32.S +++ b/arch/powerpc/mm/hash_low_32.S @@ -44,6 +44,9 @@ mmu_hash_lock: #ifdef CONFIG_SMP .text _GLOBAL(hash_page_sync) + mfmsr r10 + rlwinm r0,r10,0,17,15 /* clear bit 16 (MSR_EE) */ + mtmsr r0 lis r8,mmu_hash_lock@h ori r8,r8,mmu_hash_lock@l lis r0,0x0fff @@ -60,8 +63,9 @@ _GLOBAL(hash_page_sync) eieio li r0,0 stw r0,0(r8) - blr -#endif + mtmsr r10 + blr +#endif /* CONFIG_SMP */ /* * Load a PTE into the hash table, if possible. |