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Date: Mon, 20 Dec 2021 16:38:35 +0000
From: Christophe Leroy <christophe.leroy@...roup.eu>
To: Josh Poimboeuf <jpoimboe@...hat.com>,
Jiri Kosina <jikos@...nel.org>,
Miroslav Benes <mbenes@...e.cz>,
Petr Mladek <pmladek@...e.com>,
Joe Lawrence <joe.lawrence@...hat.com>,
Steven Rostedt <rostedt@...dmis.org>,
Ingo Molnar <mingo@...hat.com>,
"Naveen N . Rao" <naveen.n.rao@...ux.vnet.ibm.com>
CC: Christophe Leroy <christophe.leroy@...roup.eu>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
"live-patching@...r.kernel.org" <live-patching@...r.kernel.org>
Subject: [PATCH v2 11/13] powerpc/ftrace: directly call of function graph
tracer by ftrace caller
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@...roup.eu>
---
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
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