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sh: Function graph tracer support

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Add both dynamic and static function graph tracer support for sh.

Signed-off-by: Matt Fleming <matt@console-pimps.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Matt Fleming 2009-07-11 00:29:03 +00:00 committed by Paul Mundt
parent b99610fb9c
commit 327933f5d6
7 changed files with 244 additions and 1 deletions
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1
arch/sh/Kconfig
View file

@ -33,6 +33,7 @@ config SUPERH32
select HAVE_DYNAMIC_FTRACE
select HAVE_FUNCTION_TRACE_MCOUNT_TEST
select HAVE_FTRACE_SYSCALLS
select HAVE_FUNCTION_GRAPH_TRACER
select HAVE_ARCH_KGDB
select ARCH_HIBERNATION_POSSIBLE if MMU

3
arch/sh/include/asm/ftrace.h
View file

@ -13,8 +13,11 @@ extern void mcount(void);
#ifdef CONFIG_DYNAMIC_FTRACE
#define CALL_ADDR ((long)(ftrace_call))
#define STUB_ADDR ((long)(ftrace_stub))
#define GRAPH_ADDR ((long)(ftrace_graph_call))
#define CALLER_ADDR ((long)(ftrace_caller))
#define MCOUNT_INSN_OFFSET ((STUB_ADDR - CALL_ADDR) - 4)
#define GRAPH_INSN_OFFSET ((CALLER_ADDR - GRAPH_ADDR) - 4)
struct dyn_arch_ftrace {
/* No extra data needed on sh */

1
arch/sh/kernel/Makefile_32
View file

@ -30,6 +30,7 @@ obj-$(CONFIG_KPROBES) += kprobes.o
obj-$(CONFIG_GENERIC_GPIO) += gpio.o
obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o
obj-$(CONFIG_FTRACE_SYSCALLS) += ftrace.o
obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o
obj-$(CONFIG_DUMP_CODE) += disassemble.o
obj-$(CONFIG_HIBERNATION) += swsusp.o

122
arch/sh/kernel/ftrace.c
View file

@ -16,11 +16,13 @@
#include <linux/string.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <asm/ftrace.h>
#include <asm/cacheflush.h>
#include <asm/unistd.h>
#include <trace/syscall.h>
#ifdef CONFIG_DYNAMIC_FTRACE
static unsigned char ftrace_replaced_code[MCOUNT_INSN_SIZE];
static unsigned char ftrace_nop[4];
@ -133,6 +135,126 @@ int __init ftrace_dyn_arch_init(void *data)
return 0;
}
#endif /* CONFIG_DYNAMIC_FTRACE */
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
#ifdef CONFIG_DYNAMIC_FTRACE
extern void ftrace_graph_call(void);
static int ftrace_mod(unsigned long ip, unsigned long old_addr,
unsigned long new_addr)
{
unsigned char code[MCOUNT_INSN_SIZE];
if (probe_kernel_read(code, (void *)ip, MCOUNT_INSN_SIZE))
return -EFAULT;
if (old_addr != __raw_readl((unsigned long *)code))
return -EINVAL;
__raw_writel(new_addr, ip);
return 0;
}
int ftrace_enable_ftrace_graph_caller(void)
{
unsigned long ip, old_addr, new_addr;
ip = (unsigned long)(&ftrace_graph_call) + GRAPH_INSN_OFFSET;
old_addr = (unsigned long)(&skip_trace);
new_addr = (unsigned long)(&ftrace_graph_caller);
return ftrace_mod(ip, old_addr, new_addr);
}
int ftrace_disable_ftrace_graph_caller(void)
{
unsigned long ip, old_addr, new_addr;
ip = (unsigned long)(&ftrace_graph_call) + GRAPH_INSN_OFFSET;
old_addr = (unsigned long)(&ftrace_graph_caller);
new_addr = (unsigned long)(&skip_trace);
return ftrace_mod(ip, old_addr, new_addr);
}
#endif /* CONFIG_DYNAMIC_FTRACE */
/*
* Hook the return address and push it in the stack of return addrs
* in the current thread info.
*
* This is the main routine for the function graph tracer. The function
* graph tracer essentially works like this:
*
* parent is the stack address containing self_addr's return address.
* We pull the real return address out of parent and store it in
* current's ret_stack. Then, we replace the return address on the stack
* with the address of return_to_handler. self_addr is the function that
* called mcount.
*
* When self_addr returns, it will jump to return_to_handler which calls
* ftrace_return_to_handler. ftrace_return_to_handler will pull the real
* return address off of current's ret_stack and jump to it.
*/
void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
{
unsigned long old;
int faulted, err;
struct ftrace_graph_ent trace;
unsigned long return_hooker = (unsigned long)&return_to_handler;
if (unlikely(atomic_read(&current->tracing_graph_pause)))
return;
/*
* Protect against fault, even if it shouldn't
* happen. This tool is too much intrusive to
* ignore such a protection.
*/
__asm__ __volatile__(
"1: \n\t"
"mov.l @%2, %0 \n\t"
"2: \n\t"
"mov.l %3, @%2 \n\t"
"mov #0, %1 \n\t"
"3: \n\t"
".section .fixup, \"ax\" \n\t"
"4: \n\t"
"mov.l 5f, %0 \n\t"
"jmp @%0 \n\t"
" mov #1, %1 \n\t"
".balign 4 \n\t"
"5: .long 3b \n\t"
".previous \n\t"
".section __ex_table,\"a\" \n\t"
".long 1b, 4b \n\t"
".long 2b, 4b \n\t"
".previous \n\t"
: "=&r" (old), "=r" (faulted)
: "r" (parent), "r" (return_hooker)
);
if (unlikely(faulted)) {
ftrace_graph_stop();
WARN_ON(1);
return;
}
err = ftrace_push_return_trace(old, self_addr, &trace.depth, 0);
if (err == -EBUSY) {
__raw_writel(old, parent);
return;
}
trace.func = self_addr;
/* Only trace if the calling function expects to */
if (!ftrace_graph_entry(&trace)) {
current->curr_ret_stack--;
__raw_writel(old, parent);
}
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
#ifdef CONFIG_FTRACE_SYSCALLS

0
arch/sh/kernel/vmlinux_64.lds.S Normal file
View file

1
arch/sh/lib/Makefile
View file

@ -25,6 +25,7 @@ memcpy-$(CONFIG_CPU_SH4) := memcpy-sh4.o
lib-$(CONFIG_MMU) += copy_page.o clear_page.o
lib-$(CONFIG_FUNCTION_TRACER) += mcount.o
lib-$(CONFIG_FUNCTION_GRAPH_TRACER) += mcount.o
lib-y += $(memcpy-y) $(udivsi3-y)
EXTRA_CFLAGS += -Werror

117
arch/sh/lib/mcount.S
View file

@ -111,14 +111,62 @@ mcount_call:
jsr @r6
nop
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
mov.l .Lftrace_graph_return, r6
mov.l .Lftrace_stub, r7
cmp/eq r6, r7
bt 1f
mov.l .Lftrace_graph_caller, r0
jmp @r0
nop
1:
mov.l .Lftrace_graph_entry, r6
mov.l .Lftrace_graph_entry_stub, r7
cmp/eq r6, r7
bt skip_trace
mov.l .Lftrace_graph_caller, r0
jmp @r0
nop
.align 2
.Lftrace_graph_return:
.long ftrace_graph_return
.Lftrace_graph_entry:
.long ftrace_graph_entry
.Lftrace_graph_entry_stub:
.long ftrace_graph_entry_stub
.Lftrace_graph_caller:
.long ftrace_graph_caller
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
.globl skip_trace
skip_trace:
MCOUNT_LEAVE()
.align 2
.Lftrace_trace_function:
.long ftrace_trace_function
.long ftrace_trace_function
#ifdef CONFIG_DYNAMIC_FTRACE
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
/*
* NOTE: Do not move either ftrace_graph_call or ftrace_caller
* as this will affect the calculation of GRAPH_INSN_OFFSET.
*/
.globl ftrace_graph_call
ftrace_graph_call:
mov.l .Lskip_trace, r0
jmp @r0
nop
.align 2
.Lskip_trace:
.long skip_trace
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
.globl ftrace_caller
ftrace_caller:
mov.l .Lfunction_trace_stop, r0
@ -136,7 +184,12 @@ ftrace_call:
jsr @r6
nop
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
bra ftrace_graph_call
nop
#else
MCOUNT_LEAVE()
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
#endif /* CONFIG_DYNAMIC_FTRACE */
/*
@ -188,3 +241,65 @@ stack_panic:
.Lpanic_str:
.string "Stack error"
#endif /* CONFIG_STACK_DEBUG */
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
.globl ftrace_graph_caller
ftrace_graph_caller:
mov.l 2f, r0
mov.l @r0, r0
tst r0, r0
bt 1f
mov.l 3f, r1
jmp @r1
nop
1:
/*
* MCOUNT_ENTER() pushed 5 registers onto the stack, so
* the stack address containing our return address is
* r15 + 20.
*/
mov #20, r0
add r15, r0
mov r0, r4
mov.l .Lprepare_ftrace_return, r0
jsr @r0
nop
MCOUNT_LEAVE()
.align 2
2: .long function_trace_stop
3: .long skip_trace
.Lprepare_ftrace_return:
.long prepare_ftrace_return
.globl return_to_handler
return_to_handler:
/*
* Save the return values.
*/
mov.l r0, @-r15
mov.l r1, @-r15
mov #0, r4
mov.l .Lftrace_return_to_handler, r0
jsr @r0
nop
/*
* The return value from ftrace_return_handler has the real
* address that we should return to.
*/
lds r0, pr
mov.l @r15+, r1
rts
mov.l @r15+, r0
.align 2
.Lftrace_return_to_handler:
.long ftrace_return_to_handler
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */