Re: [PATCH v2 12/13] powerpc/ftrace: Prepare ftrace_64_mprofile.S for reuse by PPC32
From: Naveen N. Rao
Date: Mon Feb 14 2022 - 12:52:34 EST
Christophe Leroy wrote:
PPC64 mprofile versions and PPC32 are very similar.
Modify PPC64 version so that if can be reused for PPC32.
Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
---
.../powerpc/kernel/trace/ftrace_64_mprofile.S | 73 +++++++++++++------
1 file changed, 51 insertions(+), 22 deletions(-)
While I agree that ppc32 and -mprofile-kernel ftrace code are very
similar, I think this patch adds way too many #ifdefs. IMHO, this
makes the resultant code quite difficult to follow.
- Naveen
diff --git a/arch/powerpc/kernel/trace/ftrace_64_mprofile.S b/arch/powerpc/kernel/trace/ftrace_64_mprofile.S
index 6071e0122797..56da60e98327 100644
--- a/arch/powerpc/kernel/trace/ftrace_64_mprofile.S
+++ b/arch/powerpc/kernel/trace/ftrace_64_mprofile.S
@@ -34,13 +34,16 @@
*/
_GLOBAL(ftrace_regs_caller)
/* Save the original return address in A's stack frame */
- std r0,LRSAVE(r1)
+#ifdef CONFIG_MPROFILE_KERNEL
+ PPC_STL r0,LRSAVE(r1)
+#endif
/* Create our stack frame + pt_regs */
- stdu r1,-SWITCH_FRAME_SIZE(r1)
+ PPC_STLU r1,-SWITCH_FRAME_SIZE(r1)
/* Save all gprs to pt_regs */
SAVE_GPR(0, r1)
+#ifdef CONFIG_PPC64
SAVE_GPRS(2, 11, r1)
/* Ok to continue? */
@@ -49,10 +52,13 @@ _GLOBAL(ftrace_regs_caller)
beq ftrace_no_trace
SAVE_GPRS(12, 31, r1)
+#else
+ stmw r2, GPR2(r1)
+#endif
/* Save previous stack pointer (r1) */
addi r8, r1, SWITCH_FRAME_SIZE
- std r8, GPR1(r1)
+ PPC_STL r8, GPR1(r1)
/* Load special regs for save below */
mfmsr r8
@@ -63,10 +69,11 @@ _GLOBAL(ftrace_regs_caller)
/* Get the _mcount() call site out of LR */
mflr r7
/* Save it as pt_regs->nip */
- std r7, _NIP(r1)
+ PPC_STL r7, _NIP(r1)
/* Save the read LR in pt_regs->link */
- std r0, _LINK(r1)
+ PPC_STL r0, _LINK(r1)
+#ifdef CONFIG_PPC64
/* Save callee's TOC in the ABI compliant location */
std r2, 24(r1)
ld r2,PACATOC(r13) /* get kernel TOC in r2 */
@@ -74,8 +81,12 @@ _GLOBAL(ftrace_regs_caller)
addis r3,r2,function_trace_op@toc@ha
addi r3,r3,function_trace_op@toc@l
ld r5,0(r3)
+#else
+ lis r3,function_trace_op@ha
+ lwz r5,function_trace_op@l(r3)
+#endif
-#ifdef CONFIG_LIVEPATCH
+#ifdef CONFIG_LIVEPATCH_64
mr r14,r7 /* remember old NIP */
#endif
/* Calculate ip from nip-4 into r3 for call below */
@@ -85,10 +96,10 @@ _GLOBAL(ftrace_regs_caller)
mr r4, r0
/* Save special regs */
- std r8, _MSR(r1)
- std r9, _CTR(r1)
- std r10, _XER(r1)
- std r11, _CCR(r1)
+ PPC_STL r8, _MSR(r1)
+ PPC_STL r9, _CTR(r1)
+ PPC_STL r10, _XER(r1)
+ PPC_STL r11, _CCR(r1)
/* Load &pt_regs in r6 for call below */
addi r6, r1 ,STACK_FRAME_OVERHEAD
@@ -100,27 +111,32 @@ ftrace_regs_call:
nop
/* Load ctr with the possibly modified NIP */
- ld r3, _NIP(r1)
+ PPC_LL r3, _NIP(r1)
mtctr r3
-#ifdef CONFIG_LIVEPATCH
+#ifdef CONFIG_LIVEPATCH_64
cmpd r14, r3 /* has NIP been altered? */
#endif
/* Restore gprs */
- REST_GPR(0, r1)
+#ifdef CONFIG_PPC64
REST_GPRS(2, 31, r1)
+#else
+ lmw r2, GPR2(r1)
+#endif
/* Restore possibly modified LR */
- ld r0, _LINK(r1)
+ PPC_LL r0, _LINK(r1)
mtlr r0
+#ifdef CONFIG_PPC64
/* Restore callee's TOC */
ld r2, 24(r1)
+#endif
/* Pop our stack frame */
addi r1, r1, SWITCH_FRAME_SIZE
-#ifdef CONFIG_LIVEPATCH
+#ifdef CONFIG_LIVEPATCH_64
/* Based on the cmpd above, if the NIP was altered handle livepatch */
bne- livepatch_handler
#endif
@@ -129,6 +145,7 @@ ftrace_regs_call:
_GLOBAL(ftrace_stub)
blr
+#ifdef CONFIG_PPC64
ftrace_no_trace:
mflr r3
mtctr r3
@@ -136,25 +153,31 @@ ftrace_no_trace:
addi r1, r1, SWITCH_FRAME_SIZE
mtlr r0
bctr
+#endif
_GLOBAL(ftrace_caller)
/* Save the original return address in A's stack frame */
- std r0, LRSAVE(r1)
+#ifdef CONFIG_MPROFILE_KERNEL
+ PPC_STL r0, LRSAVE(r1)
+#endif
/* Create our stack frame + pt_regs */
- stdu r1, -SWITCH_FRAME_SIZE(r1)
+ PPC_STLU r1, -SWITCH_FRAME_SIZE(r1)
/* Save all gprs to pt_regs */
SAVE_GPRS(3, 10, r1)
+#ifdef CONFIG_PPC64
lbz r3, PACA_FTRACE_ENABLED(r13)
cmpdi r3, 0
beq ftrace_no_trace
+#endif
/* Get the _mcount() call site out of LR */
mflr r7
- std r7, _NIP(r1)
+ PPC_STL r7, _NIP(r1)
+#ifdef CONFIG_PPC64
/* Save callee's TOC in the ABI compliant location */
std r2, 24(r1)
ld r2, PACATOC(r13) /* get kernel TOC in r2 */
@@ -162,6 +185,10 @@ _GLOBAL(ftrace_caller)
addis r3, r2, function_trace_op@toc@ha
addi r3, r3, function_trace_op@toc@l
ld r5, 0(r3)
+#else
+ lis r3,function_trace_op@ha
+ lwz r5,function_trace_op@l(r3)
+#endif
#ifdef CONFIG_LIVEPATCH_64
SAVE_GPR(14, r1)
@@ -171,7 +198,7 @@ _GLOBAL(ftrace_caller)
subi r3, r7, MCOUNT_INSN_SIZE
/* Put the original return address in r4 as parent_ip */
- std r0, _LINK(r1)
+ PPC_STL r0, _LINK(r1)
mr r4, r0
/* Load &pt_regs in r6 for call below */
@@ -183,7 +210,7 @@ ftrace_call:
bl ftrace_stub
nop
- ld r3, _NIP(r1)
+ PPC_LL r3, _NIP(r1)
mtctr r3
#ifdef CONFIG_LIVEPATCH_64
cmpd r14, r3 /* has NIP been altered? */
@@ -193,11 +220,13 @@ ftrace_call:
/* Restore gprs */
REST_GPRS(3, 10, r1)
+#ifdef CONFIG_PPC64
/* Restore callee's TOC */
ld r2, 24(r1)
+#endif
/* Restore possibly modified LR */
- ld r0, _LINK(r1)
+ PPC_LL r0, _LINK(r1)
mtlr r0
/* Pop our stack frame */
@@ -209,7 +238,7 @@ ftrace_call:
#endif
bctr /* jump after _mcount site */
-#ifdef CONFIG_LIVEPATCH
+#ifdef CONFIG_LIVEPATCH_64
/*
* This function runs in the mcount context, between two functions. As
* such it can only clobber registers which are volatile and used in
--
2.33.1