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authorSteven Rostedt <rostedt@goodmis.org>2010-12-22 16:42:56 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2011-01-21 14:08:33 +1100
commit06ca2188eccbd7932636ac5bde2837297800480e (patch)
tree6eecdd819e8a96f04eda7fab9d85b04af9bdb06d /arch/powerpc
parent3cb5f1a3e58c0bd70d47d9907cc5c65192281dee (diff)
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 <rostedt@goodmis.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/kernel/entry_32.S11
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index c22dc1ec1c94..56212bc0ab08 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 */