4.7-stable review patch. If anyone has any objections, please let me know.
------------------
From: Nicholas Piggin <npig...@gmail.com>
commit cc7786d3ee7e3c979799db834b528db2c0834c2e upstream.
tabort_syscall runs with RI=1, so a nested recoverable machine
check will load the paca into r13 and overwrite what we loaded
it with, because exceptions returning to privileged mode do not
restore r13.
Fixes: b4b56f9ecab4 (powerpc/tm: Abort syscalls in active transactions)
Signed-off-by: Nick Piggin <npig...@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
arch/powerpc/kernel/entry_64.S | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -368,13 +368,13 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
tabort_syscall:
/* Firstly we need to enable TM in the kernel */
mfmsr r10
- li r13, 1
- rldimi r10, r13, MSR_TM_LG, 63-MSR_TM_LG
+ li r9, 1
+ rldimi r10, r9, MSR_TM_LG, 63-MSR_TM_LG
mtmsrd r10, 0
/* tabort, this dooms the transaction, nothing else */
- li r13, (TM_CAUSE_SYSCALL|TM_CAUSE_PERSISTENT)
- TABORT(R13)
+ li r9, (TM_CAUSE_SYSCALL|TM_CAUSE_PERSISTENT)
+ TABORT(R9)
/*
* Return directly to userspace. We have corrupted user register state,
@@ -382,8 +382,8 @@ tabort_syscall:
* resume after the tbegin of the aborted transaction with the
* checkpointed register state.
*/
- li r13, MSR_RI
- andc r10, r10, r13
+ li r9, MSR_RI
+ andc r10, r10, r9
mtmsrd r10, 1
mtspr SPRN_SRR0, r11
mtspr SPRN_SRR1, r12
