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>
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index c22dc1ec..56212bc 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -880,7 +880,18 @@
*/
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 */