[SPARC64]: More fully work around Spitfire Errata 51.
It appears that a memory barrier soon after a mispredicted
branch, not just in the delay slot, can cause the hang
condition of this cpu errata.
So move them out-of-line, and explicitly put them into
a "branch always, predict taken" delay slot which should
fully kill this problem.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/sparc64/kernel/signal32.c b/arch/sparc64/kernel/signal32.c
index b1ed230..aecccd0 100644
--- a/arch/sparc64/kernel/signal32.c
+++ b/arch/sparc64/kernel/signal32.c
@@ -877,11 +877,12 @@
unsigned long page = (unsigned long)
page_address(pte_page(*ptep));
- __asm__ __volatile__(
- " membar #StoreStore\n"
- " flush %0 + %1"
- : : "r" (page), "r" (address & (PAGE_SIZE - 1))
- : "memory");
+ wmb();
+ __asm__ __volatile__("flush %0 + %1"
+ : /* no outputs */
+ : "r" (page),
+ "r" (address & (PAGE_SIZE - 1))
+ : "memory");
}
pte_unmap(ptep);
preempt_enable();
@@ -1292,11 +1293,12 @@
unsigned long page = (unsigned long)
page_address(pte_page(*ptep));
- __asm__ __volatile__(
- " membar #StoreStore\n"
- " flush %0 + %1"
- : : "r" (page), "r" (address & (PAGE_SIZE - 1))
- : "memory");
+ wmb();
+ __asm__ __volatile__("flush %0 + %1"
+ : /* no outputs */
+ : "r" (page),
+ "r" (address & (PAGE_SIZE - 1))
+ : "memory");
}
pte_unmap(ptep);
preempt_enable();