[PATCH 10/13] powerpc: Fix register clobbering when accumulating stolen time
flat view
STALE5337d
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: 2012-03-05 02:52:47
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
Revision v2 of 2 in this series.
Revisions (2)
- v1 [diff vs current]
- v2 current
When running under a hypervisor that supports stolen time accounting, we may call C code from the macro EXCEPTION_PROLOG_COMMON in the exception entry path, which clobbers CR0. However, the FPU and vector traps rely on CR0 indicating whether we are coming from userspace or kernel to decide what to do. So we need to restore that value after the C call Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- arch/powerpc/include/asm/ppc_asm.h | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/include/asm/ppc_asm.h b/arch/powerpc/include/asm/ppc_asm.h
index 368f72f..50f73aa 100644
--- a/arch/powerpc/include/asm/ppc_asm.h
+++ b/arch/powerpc/include/asm/ppc_asm.h@@ -60,6 +60,8 @@ BEGIN_FW_FTR_SECTION; \ cmpd cr1,r11,r10; \ beq+ cr1,33f; \ bl .accumulate_stolen_time; \ + ld r12,_MSR(r1); \ + andi. r10,r12,MSR_PR; /* Restore cr0 (coming from user) */ \ 33: \ END_FW_FTR_SECTION_IFSET(FW_FEATURE_SPLPAR)
--
1.7.9