diff mbox

powerpc: Initialise paca->kstack before early_setup_secondary

Message ID 4C64ED14.9070602@ozlabs.org (mailing list archive)
State Accepted, archived
Commit f761622e59433130bc33ad086ce219feee9eb961
Delegated to: Benjamin Herrenschmidt
Headers show

Commit Message

Matt Evans Aug. 13, 2010, 6:58 a.m. UTC
As early setup calls down to slb_initialize(), we must have kstack
initialised before checking "should we add a bolted SLB entry for our kstack?"

Failing to do so means stack access requires an SLB miss exception to refill
an entry dynamically, if the stack isn't accessible via SLB(0) (kernel text
& static data).  It's not always allowable to take such a miss, and
intermittent crashes will result.

Primary CPUs don't have this issue; an SLB entry is not bolted for their
stack anyway (as that lives within SLB(0)).  This patch therefore only
affects the init of secondaries.

Signed-off-by: Matt Evans <matt@ozlabs.org>
Cc: stable <stable@kernel.org>
---
 arch/powerpc/kernel/head_64.S |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
diff mbox

Patch

diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index 844a44b..4d6681d 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -572,9 +572,6 @@  __secondary_start:
 	/* Set thread priority to MEDIUM */
 	HMT_MEDIUM
 
-	/* Do early setup for that CPU (stab, slb, hash table pointer) */
-	bl	.early_setup_secondary
-
 	/* Initialize the kernel stack.  Just a repeat for iSeries.	 */
 	LOAD_REG_ADDR(r3, current_set)
 	sldi	r28,r24,3		/* get current_set[cpu#]	 */
@@ -582,6 +579,9 @@  __secondary_start:
 	addi	r1,r1,THREAD_SIZE-STACK_FRAME_OVERHEAD
 	std	r1,PACAKSAVE(r13)
 
+	/* Do early setup for that CPU (stab, slb, hash table pointer) */
+	bl	.early_setup_secondary
+
 	/* Clear backchain so we get nice backtraces */
 	li	r7,0
 	mtlr	r7