From 06ca2188eccbd7932636ac5bde2837297800480e Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 22 Dec 2010 16:42:56 +0000 Subject: powerpc/ppc32/tracing: Add stack frame to calls of trace_hardirqs_on/off 32-bit variant of the previous patch for 64-bit: << When an interrupt occurs in userspace, we can call trace_hardirqs_on/off() With one level stack. But if we have irqsoff tracing enabled, it checks both CALLER_ADDR0 and CALLER_ADDR1. The second call goes two stack frames up. If this is from user space, then there may not exist a second stack.... >> Signed-off-by: Steven Rostedt Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kernel/entry_32.S | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'arch') diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S index c22dc1ec1c9..56212bc0ab0 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -880,7 +880,18 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_TYPE_47x) */ andi. r10,r9,MSR_EE beq 1f + /* + * Since the ftrace irqsoff latency trace checks CALLER_ADDR1, + * which is the stack frame here, we need to force a stack frame + * in case we came from user space. + */ + stwu r1,-32(r1) + mflr r0 + stw r0,4(r1) + stwu r1,-32(r1) bl trace_hardirqs_on + lwz r1,0(r1) + lwz r1,0(r1) lwz r9,_MSR(r1) 1: #endif /* CONFIG_TRACE_IRQFLAGS */ -- cgit v1.2.3