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powerpc/powernv: Fix opal_exit tracepoint opcode

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commit a7e0fb6c20 upstream.

Currently the opal_exit tracepoint usually shows the opcode as 0:

  <idle>-0     [047] d.h.   635.654292: opal_entry: opcode=63
  <idle>-0     [047] d.h.   635.654296: opal_exit: opcode=0 retval=0
  kopald-1209  [019] d...   636.420943: opal_entry: opcode=10
  kopald-1209  [019] d...   636.420959: opal_exit: opcode=0 retval=0

This is because we incorrectly load the opcode into r0 before calling
__trace_opal_exit(), whereas it expects the opcode in r3 (first function
parameter). In fact we are leaving the retval in r3, so opcode and
retval will always show the same value.

Instead load the opcode into r3, resulting in:

  <idle>-0     [040] d.h.   636.618625: opal_entry: opcode=63
  <idle>-0     [040] d.h.   636.618627: opal_exit: opcode=63 retval=0

Fixes: c49f63530b ("powernv: Add OPAL tracepoints")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Michael Ellerman
2017-02-07 21:01:01 +11:00
committed by Greg Kroah-Hartman
parent 2b58bb1682
commit fed4400cd4
1 changed files with 1 additions and 1 deletions
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2
arch/powerpc/platforms/powernv/opal-wrappers.S
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@@ -148,7 +148,7 @@ opal_tracepoint_entry:
opal_tracepoint_return:
std r3,STK_REG(R31)(r1)
mr r4,r3
ld r0,STK_REG(R23)(r1)
ld r3,STK_REG(R23)(r1)
bl __trace_opal_exit
ld r3,STK_REG(R31)(r1)
addi r1,r1,STACKFRAMESIZE