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powerpc/ftrace: directly call of function graph tracer by ftrace caller

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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@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/04d196585ff81bde06a000bd9c633a33a5b21130.1640017960.git.christophe.leroy@csgroup.eu
This commit is contained in:
Christophe Leroy 2021-12-20 16:38:35 +00:00 committed by Michael Ellerman
parent 0c81ed5ed4
commit 830213786c
4 changed files with 20 additions and 114 deletions
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6
arch/powerpc/include/asm/ftrace.h
View File

@ -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__ */

11
arch/powerpc/kernel/trace/ftrace.c
View File

@ -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

53
arch/powerpc/kernel/trace/ftrace_32.S
View File

@ -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)

64
arch/powerpc/kernel/trace/ftrace_64_mprofile.S
View File

@ -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 */