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authorMichael Neuling <mikey@neuling.org>2010-08-25 21:04:25 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2010-08-31 11:35:13 +1000
commit54a834043314c257210db2a9d59f8cc605571639 (patch)
tree7743a708fd13626c79f4773b81c39e8246cc973a /arch/powerpc/kernel/head_64.S
parentb0d278b7d3ae9115939ddcea93f516308cc367e2 (diff)
powerpc: Don't use kernel stack with translation off
In f761622e59433130bc33ad086ce219feee9eb961 we changed early_setup_secondary so it's called using the proper kernel stack rather than the emergency one. Unfortunately, this stack pointer can't be used when translation is off on PHYP as this stack pointer might be outside the RMO. This results in the following on all non zero cpus: cpu 0x1: Vector: 300 (Data Access) at [c00000001639fd10] pc: 000000000001c50c lr: 000000000000821c sp: c00000001639ff90 msr: 8000000000001000 dar: c00000001639ffa0 dsisr: 42000000 current = 0xc000000016393540 paca = 0xc000000006e00200 pid = 0, comm = swapper The original patch was only tested on bare metal system, so it never caught this problem. This changes __secondary_start so that we calculate the new stack pointer but only start using it after we've called early_setup_secondary. With this patch, the above problem goes away. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/kernel/head_64.S')
-rw-r--r--arch/powerpc/kernel/head_64.S12
1 files changed, 9 insertions, 3 deletions
diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index 4d6681dce81..c571cd3c145 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -575,13 +575,19 @@ __secondary_start:
/* Initialize the kernel stack. Just a repeat for iSeries. */
LOAD_REG_ADDR(r3, current_set)
sldi r28,r24,3 /* get current_set[cpu#] */
- ldx r1,r3,r28
- addi r1,r1,THREAD_SIZE-STACK_FRAME_OVERHEAD
- std r1,PACAKSAVE(r13)
+ ldx r14,r3,r28
+ addi r14,r14,THREAD_SIZE-STACK_FRAME_OVERHEAD
+ std r14,PACAKSAVE(r13)
/* Do early setup for that CPU (stab, slb, hash table pointer) */
bl .early_setup_secondary
+ /*
+ * setup the new stack pointer, but *don't* use this until
+ * translation is on.
+ */
+ mr r1, r14
+
/* Clear backchain so we get nice backtraces */
li r7,0
mtlr r7