From 53545131ecea3a41f4b1b4f6d8b04c8a2a78ac35 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Mon, 25 Jul 2016 14:26:51 +1000 Subject: [PATCH] powerpc/tm: do not use r13 for tabort_syscall 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 Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/kernel/entry_64.S | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index a94f155db78e..edba294620db 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -334,13 +334,13 @@ syscall_exit_work: 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, @@ -348,8 +348,8 @@ 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 -- 2.20.1