[PATCH 3.18 115/183] powernv: Fix OPAL tracepoint code

Greg Kroah-Hartman
2015-01-25T18:39:45Z

From: Anton Blanchard <anton@samba.org>

commit bfe5fda8e7ced129716f5741cf7ed2592a338824 upstream.

Patch c49f63530bb6 ("powernv: Add OPAL tracepoints") has a spurious
store to the stack:

ld r12,opal_tracepoint_refcount@toc(r2); \
std r12,32(r1); \

The store was originally used to save the current tracepoint status
so the entry and the exit tracepoints were always balanced. In the
end I just created a separate path when tracepoints are enabled.

The offset on the stack used for this store is not valid for ABIv2
and it causes strange issues. I noticed it because OPAL console input
was broken.

Fixes: c49f63530bb6 ("powernv: Add OPAL tracepoints")
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/powerpc/platforms/powernv/opal-wrappers.S | 1 -
1 file changed, 1 deletion(-)

--- a/arch/powerpc/platforms/powernv/opal-wrappers.S
+++ b/arch/powerpc/platforms/powernv/opal-wrappers.S
@@ -40,7 +40,6 @@ BEGIN_FTR_SECTION; \
b 1f; \
END_FTR_SECTION(0, 1); \
ld r12,opal_tracepoint_refcount@toc(r2); \
- std r12,32(r1); \
cmpdi r12,0; \
bne- LABEL; \
1: