csky: ftrace call graph supported.

With csky-gcc -pg -mbacktrace, ftrace call graph supported.

Signed-off-by: Guo Ren <ren_guo@c-sky.com>
This commit is contained in:
Guo Ren 2018-12-15 21:04:27 +08:00
parent 230c77a5e9
commit d7950be145
4 changed files with 152 additions and 21 deletions

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@ -30,6 +30,7 @@ config CSKY
select GENERIC_SMP_IDLE_THREAD
select HAVE_ARCH_TRACEHOOK
select HAVE_FUNCTION_TRACER
select HAVE_FUNCTION_GRAPH_TRACER
select HAVE_GENERIC_DMA_COHERENT
select HAVE_KERNEL_GZIP
select HAVE_KERNEL_LZO

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@ -2,23 +2,123 @@
// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
#include <linux/linkage.h>
#include <asm/ftrace.h>
ENTRY (_mcount)
subi sp, 20
/*
* csky-gcc with -pg will put the following asm after prologue:
* push r15
* jsri _mcount
*
* stack layout after mcount_enter in _mcount():
*
* current sp => 0:+-------+
* | a0-a3 | -> must save all argument regs
* +16:+-------+
* | lr | -> _mcount lr (instrumente function's pc)
* +20:+-------+
* | fp=r8 | -> instrumented function fp
* +24:+-------+
* | plr | -> instrumented function lr (parent's pc)
* +-------+
*/
.macro mcount_enter
subi sp, 24
stw a0, (sp, 0)
stw a1, (sp, 4)
stw a2, (sp, 8)
stw a3, (sp, 12)
stw lr, (sp, 16)
mov a1, lr
ldw a0, (sp, 20)
jsri csky_mcount
stw r8, (sp, 20)
.endm
.macro mcount_exit
ldw a0, (sp, 0)
ldw a1, (sp, 4)
ldw a2, (sp, 8)
ldw a3, (sp, 12)
ldw t1, (sp, 16)
ldw lr, (sp, 20)
addi sp, 24
ldw r8, (sp, 20)
ldw lr, (sp, 24)
addi sp, 28
jmp t1
END (_mcount)
.endm
.macro save_return_regs
subi sp, 16
stw a0, (sp, 0)
stw a1, (sp, 4)
stw a2, (sp, 8)
stw a3, (sp, 12)
.endm
.macro restore_return_regs
mov lr, a0
ldw a0, (sp, 0)
ldw a1, (sp, 4)
ldw a2, (sp, 8)
ldw a3, (sp, 12)
addi sp, 16
.endm
ENTRY(ftrace_stub)
jmp lr
END(ftrace_stub)
ENTRY(_mcount)
mcount_enter
/* r26 is link register, only used with jsri translation */
lrw r26, ftrace_trace_function
ldw r26, (r26, 0)
lrw a1, ftrace_stub
cmpne r26, a1
bf skip_ftrace
mov a0, lr
subi a0, MCOUNT_INSN_SIZE
ldw a1, (sp, 24)
jsr r26
#ifndef CONFIG_FUNCTION_GRAPH_TRACER
skip_ftrace:
mcount_exit
#else
skip_ftrace:
lrw a0, ftrace_graph_return
ldw a0, (a0, 0)
lrw a1, ftrace_stub
cmpne a0, a1
bt ftrace_graph_caller
lrw a0, ftrace_graph_entry
ldw a0, (a0, 0)
lrw a1, ftrace_graph_entry_stub
cmpne a0, a1
bt ftrace_graph_caller
mcount_exit
#endif
END(_mcount)
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
ENTRY(ftrace_graph_caller)
mov a0, sp
addi a0, 24
ldw a1, (sp, 16)
subi a1, MCOUNT_INSN_SIZE
mov a2, r8
lrw r26, prepare_ftrace_return
jsr r26
mcount_exit
END(ftrace_graph_caller)
ENTRY(return_to_handler)
save_return_regs
mov a0, r8
jsri ftrace_return_to_handler
restore_return_regs
jmp lr
END(return_to_handler)
#endif

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@ -4,6 +4,10 @@
#ifndef __ASM_CSKY_FTRACE_H
#define __ASM_CSKY_FTRACE_H
extern void _mcount(unsigned long from_pc);
#define MCOUNT_INSN_SIZE 4
#define HAVE_FUNCTION_GRAPH_FP_TEST
#define HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
#endif /* __ASM_CSKY_FTRACE_H */

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@ -4,21 +4,47 @@
#include <linux/ftrace.h>
#include <linux/uaccess.h>
extern void (*ftrace_trace_function)(unsigned long, unsigned long,
struct ftrace_ops*, struct pt_regs*);
noinline void __naked ftrace_stub(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *regs)
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
unsigned long frame_pointer)
{
asm volatile ("\n");
}
unsigned long return_hooker = (unsigned long)&return_to_handler;
unsigned long old;
noinline void csky_mcount(unsigned long from_pc, unsigned long self_pc)
{
if (ftrace_trace_function != ftrace_stub)
ftrace_trace_function(self_pc, from_pc, NULL, NULL);
if (unlikely(atomic_read(&current->tracing_graph_pause)))
return;
old = *parent;
if (!function_graph_enter(old, self_addr,
*(unsigned long *)frame_pointer, parent)) {
/*
* For csky-gcc function has sub-call:
* subi sp, sp, 8
* stw r8, (sp, 0)
* mov r8, sp
* st.w r15, (sp, 0x4)
* push r15
* jl _mcount
* We only need set *parent for resume
*
* For csky-gcc function has no sub-call:
* subi sp, sp, 4
* stw r8, (sp, 0)
* mov r8, sp
* push r15
* jl _mcount
* We need set *parent and *(frame_pointer + 4) for resume,
* because lr is resumed twice.
*/
*parent = return_hooker;
frame_pointer += 4;
if (*(unsigned long *)frame_pointer == old)
*(unsigned long *)frame_pointer = return_hooker;
}
}
#endif
/* _mcount is defined in abi's mcount.S */
extern void _mcount(void);
EXPORT_SYMBOL(_mcount);