Commit 5779e3c0 authored by Donglin Peng's avatar Donglin Peng Committed by Steven Rostedt (Google)
Browse files

LoongArch: ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL 

The previous patch ("function_graph: Support recording and printing
the return value of function") has laid the groundwork for the for
the funcgraph-retval, and this modification makes it available on
the LoongArch platform.

We introduce a new structure called fgraph_ret_regs for the LoongArch
platform to hold return registers and the frame pointer. We then fill
its content in the return_to_handler and pass its address to the
function ftrace_return_to_handler to record the return value.

Link: https://lkml.kernel.org/r/c5462255e435fab363895c2d7433bc0f5a140411.1680954589.git.pengdonglin@sangfor.com.cn



Reviewed-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
Signed-off-by: default avatarDonglin Peng <pengdonglin@sangfor.com.cn>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent d938ba17

arch/loongarch/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -103,6 +103,7 @@ config LOONGARCH 
	select HAVE_FTRACE_MCOUNT_RECORD

	select HAVE_FUNCTION_ARG_ACCESS_API

	select HAVE_FUNCTION_ERROR_INJECTION

	select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER

	select HAVE_FUNCTION_GRAPH_TRACER

	select HAVE_FUNCTION_TRACER

	select HAVE_GENERIC_VDSO

arch/loongarch/include/asm/ftrace.h

+22 −0
Original line number Diff line number Diff line
@@ -100,4 +100,26 @@ __arch_ftrace_set_direct_caller(struct pt_regs *regs, unsigned long addr) 


#endif /* CONFIG_FUNCTION_TRACER */



#ifndef __ASSEMBLY__

#ifdef CONFIG_FUNCTION_GRAPH_TRACER

struct fgraph_ret_regs {

	/* a0 - a1 */

	unsigned long regs[2];



	unsigned long fp;

	unsigned long __unused;

};



static inline unsigned long fgraph_ret_regs_return_value(struct fgraph_ret_regs *ret_regs)

{

	return ret_regs->regs[0];

}



static inline unsigned long fgraph_ret_regs_frame_pointer(struct fgraph_ret_regs *ret_regs)

{

	return ret_regs->fp;

}

#endif /* ifdef CONFIG_FUNCTION_GRAPH_TRACER */

#endif



#endif /* _ASM_LOONGARCH_FTRACE_H */

arch/loongarch/kernel/asm-offsets.c

+14 −1
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include <asm/cpu-info.h>

#include <asm/ptrace.h>

#include <asm/processor.h>

#include <asm/ftrace.h>



void output_ptreg_defines(void)

{
@@ -272,3 +273,15 @@ void output_pbe_defines(void) 
	BLANK();

}

#endif



#ifdef CONFIG_FUNCTION_GRAPH_TRACER

void output_fgraph_ret_regs_defines(void)

{

	COMMENT("LoongArch fgraph_ret_regs offsets.");

	OFFSET(FGRET_REGS_A0, fgraph_ret_regs, regs[0]);

	OFFSET(FGRET_REGS_A1, fgraph_ret_regs, regs[1]);

	OFFSET(FGRET_REGS_FP, fgraph_ret_regs, fp);

	DEFINE(FGRET_REGS_SIZE, sizeof(struct fgraph_ret_regs));

	BLANK();

}

#endif

arch/loongarch/kernel/mcount.S

+8 −6
Original line number Diff line number Diff line
@@ -79,18 +79,20 @@ SYM_FUNC_START(ftrace_graph_caller) 
SYM_FUNC_END(ftrace_graph_caller)



SYM_FUNC_START(return_to_handler)

	PTR_ADDI	sp, sp, -2 * SZREG

	PTR_S		a0, sp, 0

	PTR_S		a1, sp, SZREG

	PTR_ADDI	sp, sp, -FGRET_REGS_SIZE

	PTR_S		a0, sp, FGRET_REGS_A0

	PTR_S		a1, sp, FGRET_REGS_A1

	PTR_S		zero, sp, FGRET_REGS_FP



	move		a0, sp

	bl		ftrace_return_to_handler



	/* Restore the real parent address: a0 -> ra */

	move		ra, a0



	PTR_L		a0, sp, 0

	PTR_L		a1, sp, SZREG

	PTR_ADDI	sp, sp, 2 * SZREG

	PTR_L		a0, sp, FGRET_REGS_A0

	PTR_L		a1, sp, FGRET_REGS_A1

	PTR_ADDI	sp, sp, FGRET_REGS_SIZE

	jr		ra

SYM_FUNC_END(return_to_handler)

#endif /* CONFIG_FUNCTION_GRAPH_TRACER */

arch/loongarch/kernel/mcount_dyn.S

+8 −7
Original line number Diff line number Diff line
@@ -136,18 +136,19 @@ SYM_CODE_END(ftrace_graph_caller) 


SYM_CODE_START(return_to_handler)

	/* Save return value regs */

	PTR_ADDI 	sp, sp, -2 * SZREG

	PTR_S		a0, sp, 0

	PTR_S		a1, sp, SZREG

	PTR_ADDI	sp, sp, -FGRET_REGS_SIZE

	PTR_S		a0, sp, FGRET_REGS_A0

	PTR_S		a1, sp, FGRET_REGS_A1

	PTR_S		zero, sp, FGRET_REGS_FP



	move		a0, zero

	move		a0, sp

	bl		ftrace_return_to_handler

	move		ra, a0



	/* Restore return value regs */

	PTR_L		a0, sp, 0

	PTR_L		a1, sp, SZREG

	PTR_ADDI 	sp, sp, 2 * SZREG

	PTR_L		a0, sp, FGRET_REGS_A0

	PTR_L		a1, sp, FGRET_REGS_A1

	PTR_ADDI	sp, sp, FGRET_REGS_SIZE



	jr		ra

SYM_CODE_END(return_to_handler)