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Commit 06ca2188 authored by Steven Rostedt's avatar Steven Rostedt Committed by Benjamin Herrenschmidt
Browse files

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: default avatarSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 3cb5f1a3

arch/powerpc/kernel/entry_32.S

+11 −0
Original line number Diff line number Diff line
@@ -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 */