path: root/arch
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authorMichael Neuling <mikey@neuling.org>2013-06-28 18:17:09 +1000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2013-06-30 15:49:43 +1000
commit090b9284d72561644d17a6e568d29c9e472c9865 (patch)
treeabaa4ab0c0f59bd15c1748192a863095af2f3296 /arch
parent80aa0fb4940bf8ee52bcb574d74459a7aea45621 (diff)
powerpc/tm: Clear MSR RI in non-recoverable TM code
When we treclaim and trecheckpoint there's an unavoidable period when r1 will not be a valid kernel stack pointer. This patch clears the MSR recoverable interrupt (RI) bit over these regions to indicate we have an invalid kernel stack pointer. For treclaim, the region over which we clear MSR RI is larger than required to avoid the need for an extra costly mtmsrd. Thanks to Paulus for suggesting this change. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch')
1 files changed, 16 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/tm.S b/arch/powerpc/kernel/tm.S
index 2da67e7a16d5..51be8fb24803 100644
--- a/arch/powerpc/kernel/tm.S
+++ b/arch/powerpc/kernel/tm.S
@@ -112,9 +112,18 @@ _GLOBAL(tm_reclaim)
std r3, STACK_PARAM(0)(r1)
+ /* We need to setup MSR for VSX register save instructions. Here we
+ * also clear the MSR RI since when we do the treclaim, we won't have a
+ * valid kernel pointer for a while. We clear RI here as it avoids
+ * adding another mtmsr closer to the treclaim. This makes the region
+ * maked as non-recoverable wider than it needs to be but it saves on
+ * inserting another mtmsrd later.
+ */
mfmsr r14
mr r15, r14
ori r15, r15, MSR_FP
+ li r16, MSR_RI
+ andc r15, r15, r16
oris r15, r15, MSR_VEC@h
@@ -349,9 +358,10 @@ restore_gprs:
mtcr r5
mtxer r6
- /* MSR and flags: We don't change CRs, and we don't need to alter
- * MSR.
+ /* Clear the MSR RI since we are about to change R1. EE is already off
+ li r4, 0
+ mtmsrd r4, 1
REST_4GPRS(0, r7) /* GPR0-3 */
REST_GPR(4, r7) /* GPR4-6 */
@@ -377,6 +387,10 @@ restore_gprs:
+ /* R1 is restored, so we are recoverable again. EE is still off */
+ li r4, MSR_RI
+ mtmsrd r4, 1
addi r1, r1, TM_FRAME_SIZE