[PATCH 4/5] powerpc/kprobes: Setup consistent pt_regs across kprobes, optprobes and KPROBES_ON_FTRACE

["Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>]

Ensure a more consistent pt_regs across kprobes, optprobes and
KPROBES_ON_FTRACE:
- Drop setting trap to 0x700 under optprobes. This is not accurate and
  is unnecessary. Instead, zero it out for both optprobes and
  KPROBES_ON_FTRACE.
- Save irq soft mask in the ftrace handler, similar to what we do in
  optprobes and trap-based kprobes.
- Drop setting orig_gpr3 and result to zero in optprobes. These are not
  relevant under kprobes and should not be used by the handlers.

Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
---
 arch/powerpc/kernel/optprobes_head.S        | 5 +----
 arch/powerpc/kernel/trace/ftrace_mprofile.S | 6 ++++++
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/kernel/optprobes_head.S b/arch/powerpc/kernel/optprobes_head.S
index cd4e7bc32609d3..06df09b4e8b155 100644
--- a/arch/powerpc/kernel/optprobes_head.S
+++ b/arch/powerpc/kernel/optprobes_head.S
@@ -49,11 +49,8 @@ optprobe_template_entry:
 	/* Save SPRS */
 	mfmsr	r5
 	PPC_STL	r5,_MSR(r1)
-	li	r5,0x700
-	PPC_STL	r5,_TRAP(r1)
 	li	r5,0
-	PPC_STL	r5,ORIG_GPR3(r1)
-	PPC_STL	r5,RESULT(r1)
+	PPC_STL	r5,_TRAP(r1)
 	mfctr	r5
 	PPC_STL	r5,_CTR(r1)
 	mflr	r5
diff --git a/arch/powerpc/kernel/trace/ftrace_mprofile.S b/arch/powerpc/kernel/trace/ftrace_mprofile.S
index d031093bc43671..f82004089426e6 100644
--- a/arch/powerpc/kernel/trace/ftrace_mprofile.S
+++ b/arch/powerpc/kernel/trace/ftrace_mprofile.S
@@ -107,6 +107,12 @@
 	PPC_STL	r9, _CTR(r1)
 	PPC_STL	r10, _XER(r1)
 	PPC_STL	r11, _CCR(r1)
+#ifdef CONFIG_PPC64
+	lbz     r7, PACAIRQSOFTMASK(r13)
+	std     r7, SOFTE(r1)
+#endif
+	li	r8, 0
+	PPC_STL	r8, _TRAP(r1)
 	.endif
 
 	/* Load &pt_regs in r6 for call below */
-- 
2.38.0