Commit d7950be1 authored by Guo Ren's avatar Guo Ren
Browse files

csky: ftrace call graph supported. 



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

Signed-off-by: default avatarGuo Ren <ren_guo@c-sky.com>
parent 230c77a5

arch/csky/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -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

arch/csky/abiv2/mcount.S

+108 −8
Original line number Diff line number Diff line
@@ -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

.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

arch/csky/include/asm/ftrace.h

+5 −1
Original line number Diff line number Diff line
@@ -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 */

arch/csky/kernel/ftrace.c

+37 −11
Original line number Diff line number Diff line
@@ -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*);

#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;

	unsigned long old;



	if (unlikely(atomic_read(&current->tracing_graph_pause)))

		return;



noinline void __naked ftrace_stub(unsigned long ip, unsigned long parent_ip,

				  struct ftrace_ops *op, struct pt_regs *regs)

{

	asm volatile ("\n");

}

	old = *parent;



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 (!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);