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ARM: ftrace: function graph tracer support 

Cc: Tim Bird <tim.bird@am.sony.com>
[rabin@rab.in: rebase on top of latest code,
	       keep code in ftrace.c instead of separate file,
	       check for ftrace_graph_entry also]
Signed-off-by: Rabin Vincent <rabin@rab.in>
This commit is contained in:
Tim Bird 2010-10-09 22:24:38 +05:30 committed by Rabin Vincent
parent d3b9dc9dd2
commit 376cfa8730
3 changed files with 82 additions and 1 deletions
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3
arch/arm/kernel/Makefile
View File

@ -5,7 +5,7 @@
CPPFLAGS_vmlinux.lds := -DTEXT_OFFSET=$(TEXT_OFFSET)
AFLAGS_head.o := -DTEXT_OFFSET=$(TEXT_OFFSET)
ifdef CONFIG_DYNAMIC_FTRACE
ifdef CONFIG_FUNCTION_TRACER
CFLAGS_REMOVE_ftrace.o = -pg
endif
@ -33,6 +33,7 @@ obj-$(CONFIG_SMP) += smp.o
obj-$(CONFIG_HAVE_ARM_SCU) += smp_scu.o
obj-$(CONFIG_HAVE_ARM_TWD) += smp_twd.o
obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o
obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o
obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o
obj-$(CONFIG_KPROBES) += kprobes.o kprobes-decode.o
obj-$(CONFIG_ATAGS_PROC) += atags.o

46
arch/arm/kernel/entry-common.S
View File

@ -148,6 +148,20 @@ ENDPROC(ret_from_fork)
adr r0, .Lftrace_stub
cmp r0, r2
bne 1f
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
ldr r1, =ftrace_graph_return
ldr r2, [r1]
cmp r0, r2
bne ftrace_graph_caller\suffix
ldr r1, =ftrace_graph_entry
ldr r2, [r1]
ldr r0, =ftrace_graph_entry_stub
cmp r0, r2
bne ftrace_graph_caller\suffix
#endif
mcount_exit
1: mcount_get_lr r1 @ lr of instrumented func
@ -172,6 +186,15 @@ ftrace_call\suffix:
mcount_exit
.endm
.macro __ftrace_graph_caller
sub r0, fp, #4 @ &lr of instrumented routine (&parent)
mov r1, lr @ instrumented routine (func)
sub r1, r1, #MCOUNT_INSN_SIZE
mov r2, fp @ frame pointer
bl prepare_ftrace_return
mcount_exit
.endm
#ifdef CONFIG_OLD_MCOUNT
/*
* mcount
@ -206,6 +229,12 @@ ENTRY(ftrace_caller_old)
ENDPROC(ftrace_caller_old)
#endif
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
ENTRY(ftrace_graph_caller_old)
__ftrace_graph_caller
ENDPROC(ftrace_graph_caller_old)
#endif
.purgem mcount_enter
.purgem mcount_get_lr
.purgem mcount_exit
@ -244,10 +273,27 @@ ENTRY(ftrace_caller)
ENDPROC(ftrace_caller)
#endif
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
ENTRY(ftrace_graph_caller)
__ftrace_graph_caller
ENDPROC(ftrace_graph_caller)
#endif
.purgem mcount_enter
.purgem mcount_get_lr
.purgem mcount_exit
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
.globl return_to_handler
return_to_handler:
stmdb sp!, {r0-r3}
mov r0, fp @ frame pointer
bl ftrace_return_to_handler
mov lr, r0 @ r0 has real ret addr
ldmia sp!, {r0-r3}
mov pc, lr
#endif
ENTRY(ftrace_stub)
.Lftrace_stub:
mov pc, lr

34
arch/arm/kernel/ftrace.c
View File

@ -24,6 +24,7 @@
#define NOP 0xe8bd4000 /* pop {lr} */
#endif
#ifdef CONFIG_DYNAMIC_FTRACE
#ifdef CONFIG_OLD_MCOUNT
#define OLD_MCOUNT_ADDR ((unsigned long) mcount)
#define OLD_FTRACE_ADDR ((unsigned long) ftrace_caller_old)
@ -193,3 +194,36 @@ int __init ftrace_dyn_arch_init(void *data)
return 0;
}
#endif /* CONFIG_DYNAMIC_FTRACE */
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
unsigned long frame_pointer)
{
unsigned long return_hooker = (unsigned long) &return_to_handler;
struct ftrace_graph_ent trace;
unsigned long old;
int err;
if (unlikely(atomic_read(&current->tracing_graph_pause)))
return;
old = *parent;
*parent = return_hooker;
err = ftrace_push_return_trace(old, self_addr, &trace.depth,
frame_pointer);
if (err == -EBUSY) {
*parent = old;
return;
}
trace.func = self_addr;
/* Only trace if the calling function expects to */
if (!ftrace_graph_entry(&trace)) {
current->curr_ret_stack--;
*parent = old;
}
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */