Hi Christophe,
Thanks for your work enabling DYNAMIC_FTRACE_WITH_ARGS on powerpc. Sorry
for the late review on this series, but I have a few comments below.
Christophe Leroy wrote:
In order to implement CONFIG_DYNAMIC_FTRACE_WITH_ARGS, change ftrace_caller()
to handle LIVEPATCH the same way as frace_caller_regs().
Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu>
---
.../powerpc/kernel/trace/ftrace_64_mprofile.S | 25 ++++++++++++++-----
1 file changed, 19 insertions(+), 6 deletions(-)
I think we also need to save r1 into pt_regs so that the stack pointer
is available in the callbacks.
Other than that, a few minor nits below...
diff --git a/arch/powerpc/kernel/trace/ftrace_64_mprofile.S
b/arch/powerpc/kernel/trace/ftrace_64_mprofile.S
index d636fc755f60..f6f787819273 100644
--- a/arch/powerpc/kernel/trace/ftrace_64_mprofile.S
+++ b/arch/powerpc/kernel/trace/ftrace_64_mprofile.S
@@ -172,14 +172,19 @@ _GLOBAL(ftrace_caller)
addi r3, r3, function_trace_op@toc@l
ld r5, 0(r3)
+#ifdef CONFIG_LIVEPATCH_64
+ SAVE_GPR(14, r1)
+ mr r14,r7 /* remember old NIP */
^ add a space
+#endif
Please add a blank line here, to match the formatting for the rest of
this file.
/* Calculate ip from nip-4 into r3 for call below */
subi r3, r7, MCOUNT_INSN_SIZE
/* Put the original return address in r4 as parent_ip */
+ std r0, _LINK(r1)
mr r4, r0
- /* Set pt_regs to NULL */
- li r6, 0
+ /* Load &pt_regs in r6 for call below */
+ addi r6, r1 ,STACK_FRAME_OVERHEAD
^^ incorrect spacing
/* ftrace_call(r3, r4, r5, r6) */
.globl ftrace_call
@@ -189,6 +194,10 @@ ftrace_call:
ld r3, _NIP(r1)
mtctr r3
Another blank line here.
+#ifdef CONFIG_LIVEPATCH_64
+ cmpd r14, r3 /* has NIP been altered? */
+ REST_GPR(14, r1)
+#endif
/* Restore gprs */
REST_GPRS(3, 10, r1)
@@ -196,13 +205,17 @@ ftrace_call:
/* Restore callee's TOC */
ld r2, 24(r1)
+ /* Restore possibly modified LR */
+ ld r0, _LINK(r1)
+ mtlr r0
+
/* Pop our stack frame */
addi r1, r1, SWITCH_FRAME_SIZE
- /* Reload original LR */
- ld r0, LRSAVE(r1)
- mtlr r0
-
+#ifdef CONFIG_LIVEPATCH_64
+ /* Based on the cmpd above, if the NIP was altered handle livepatch */
+ bne- livepatch_handler
+#endif
Here too.
/* Handle function_graph or go back */
b ftrace_caller_common
- Naveen
