[PATCH v2 11/13] powerpc/ftrace: directly call of function graph tracer by ftrace caller
From: Christophe Leroy
Date: Mon Dec 20 2021 - 11:39:05 EST
Modify function graph tracer to be handled directly by the standard
ftrace caller.
This is made possible as powerpc now supports
CONFIG_DYNAMIC_FTRACE_WITH_ARGS.
This change simplifies the call of function graph ftrace.
Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
---
arch/powerpc/include/asm/ftrace.h | 6 ++
arch/powerpc/kernel/trace/ftrace.c | 11 ++++
arch/powerpc/kernel/trace/ftrace_32.S | 53 +--------------
.../powerpc/kernel/trace/ftrace_64_mprofile.S | 64 +------------------
4 files changed, 20 insertions(+), 114 deletions(-)
diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h
index 45c3d6f11daa..70b457097098 100644
--- a/arch/powerpc/include/asm/ftrace.h
+++ b/arch/powerpc/include/asm/ftrace.h
@@ -38,6 +38,12 @@ static __always_inline void ftrace_instruction_pointer_set(struct ftrace_regs *f
{
regs_set_return_ip(&fregs->regs, ip);
}
+
+struct ftrace_ops;
+
+#define ftrace_graph_func ftrace_graph_func
+void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
+ struct ftrace_ops *op, struct ftrace_regs *fregs);
#endif
#endif /* __ASSEMBLY__ */
diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c
index ce673764cb69..74a176e394ef 100644
--- a/arch/powerpc/kernel/trace/ftrace.c
+++ b/arch/powerpc/kernel/trace/ftrace.c
@@ -917,6 +917,9 @@ static int ftrace_modify_ftrace_graph_caller(bool enable)
unsigned long stub = (unsigned long)(&ftrace_graph_stub);
ppc_inst_t old, new;
+ if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_ARGS))
+ return 0;
+
old = ftrace_call_replace(ip, enable ? stub : addr, 0);
new = ftrace_call_replace(ip, enable ? addr : stub, 0);
@@ -955,6 +958,14 @@ unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip,
out:
return parent;
}
+
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS
+void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
+ struct ftrace_ops *op, struct ftrace_regs *fregs)
+{
+ fregs->regs.link = prepare_ftrace_return(parent_ip, ip, fregs->regs.gpr[1]);
+}
+#endif
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
#ifdef PPC64_ELF_ABI_v1
diff --git a/arch/powerpc/kernel/trace/ftrace_32.S b/arch/powerpc/kernel/trace/ftrace_32.S
index c4055b41af5f..2b425da97a6b 100644
--- a/arch/powerpc/kernel/trace/ftrace_32.S
+++ b/arch/powerpc/kernel/trace/ftrace_32.S
@@ -59,13 +59,6 @@ ftrace_call:
mtlr r0
addi r1, r1, INT_FRAME_SIZE
-ftrace_caller_common:
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-.globl ftrace_graph_call
-ftrace_graph_call:
- b ftrace_graph_stub
-_GLOBAL(ftrace_graph_stub)
-#endif
/* old link register ends up in ctr reg */
bctr
@@ -135,52 +128,10 @@ ftrace_regs_call:
/* Pop our stack frame */
addi r1, r1, INT_FRAME_SIZE
-
- b ftrace_caller_common
-
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-_GLOBAL(ftrace_graph_caller)
- stwu r1,-48(r1)
- stw r3, 12(r1)
- stw r4, 16(r1)
- stw r5, 20(r1)
- stw r6, 24(r1)
- stw r7, 28(r1)
- stw r8, 32(r1)
- stw r9, 36(r1)
- stw r10,40(r1)
-
- addi r5, r1, 48
- mfctr r4 /* ftrace_caller has moved local addr here */
- stw r4, 44(r1)
- mflr r3 /* ftrace_caller has restored LR from stack */
- subi r4, r4, MCOUNT_INSN_SIZE
-
- bl prepare_ftrace_return
- nop
-
- /*
- * prepare_ftrace_return gives us the address we divert to.
- * Change the LR in the callers stack frame to this.
- */
- stw r3,52(r1)
- mtlr r3
- lwz r0,44(r1)
- mtctr r0
-
- lwz r3, 12(r1)
- lwz r4, 16(r1)
- lwz r5, 20(r1)
- lwz r6, 24(r1)
- lwz r7, 28(r1)
- lwz r8, 32(r1)
- lwz r9, 36(r1)
- lwz r10,40(r1)
-
- addi r1, r1, 48
-
+ /* old link register ends up in ctr reg */
bctr
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
_GLOBAL(return_to_handler)
/* need to save return values */
stwu r1, -16(r1)
diff --git a/arch/powerpc/kernel/trace/ftrace_64_mprofile.S b/arch/powerpc/kernel/trace/ftrace_64_mprofile.S
index f6f787819273..6071e0122797 100644
--- a/arch/powerpc/kernel/trace/ftrace_64_mprofile.S
+++ b/arch/powerpc/kernel/trace/ftrace_64_mprofile.S
@@ -124,15 +124,6 @@ ftrace_regs_call:
/* Based on the cmpd above, if the NIP was altered handle livepatch */
bne- livepatch_handler
#endif
-
-ftrace_caller_common:
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-.globl ftrace_graph_call
-ftrace_graph_call:
- b ftrace_graph_stub
-_GLOBAL(ftrace_graph_stub)
-#endif
-
bctr /* jump after _mcount site */
_GLOBAL(ftrace_stub)
@@ -216,8 +207,7 @@ ftrace_call:
/* Based on the cmpd above, if the NIP was altered handle livepatch */
bne- livepatch_handler
#endif
- /* Handle function_graph or go back */
- b ftrace_caller_common
+ bctr /* jump after _mcount site */
#ifdef CONFIG_LIVEPATCH
/*
@@ -286,55 +276,3 @@ livepatch_handler:
/* Return to original caller of live patched function */
blr
#endif /* CONFIG_LIVEPATCH */
-
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-_GLOBAL(ftrace_graph_caller)
- stdu r1, -112(r1)
- /* with -mprofile-kernel, parameter regs are still alive at _mcount */
- std r10, 104(r1)
- std r9, 96(r1)
- std r8, 88(r1)
- std r7, 80(r1)
- std r6, 72(r1)
- std r5, 64(r1)
- std r4, 56(r1)
- std r3, 48(r1)
-
- /* Save callee's TOC in the ABI compliant location */
- std r2, 24(r1)
- ld r2, PACATOC(r13) /* get kernel TOC in r2 */
-
- addi r5, r1, 112
- mfctr r4 /* ftrace_caller has moved local addr here */
- std r4, 40(r1)
- mflr r3 /* ftrace_caller has restored LR from stack */
- subi r4, r4, MCOUNT_INSN_SIZE
-
- bl prepare_ftrace_return
- nop
-
- /*
- * prepare_ftrace_return gives us the address we divert to.
- * Change the LR to this.
- */
- mtlr r3
-
- ld r0, 40(r1)
- mtctr r0
- ld r10, 104(r1)
- ld r9, 96(r1)
- ld r8, 88(r1)
- ld r7, 80(r1)
- ld r6, 72(r1)
- ld r5, 64(r1)
- ld r4, 56(r1)
- ld r3, 48(r1)
-
- /* Restore callee's TOC */
- ld r2, 24(r1)
-
- addi r1, r1, 112
- mflr r0
- std r0, LRSAVE(r1)
- bctr
-#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
--
2.33.1