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Commit a1808257 authored by Zong Li's avatar Zong Li Committed by Greentime Hu
Browse files

nds32/ftrace: Support static function tracer 



This patch support the static function tracer. On nds32 ABI, we need to
always push return address to stack for __builtin_return_address can
work correctly, otherwise, it will get the wrong value of $lp at leaf
function.

Signed-off-by: default avatarZong Li <zong@andestech.com>
Acked-by: default avatarGreentime Hu <greentime@andestech.com>
Signed-off-by: default avatarGreentime Hu <greentime@andestech.com>
parent 487913ab

arch/nds32/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -40,6 +40,7 @@ config NDS32 
	select NO_IOPORT_MAP

	select RTC_LIB

	select THREAD_INFO_IN_TASK

	select HAVE_FUNCTION_TRACER

	help

	  Andes(nds32) Linux support.

arch/nds32/Makefile

+4 −0
Original line number Diff line number Diff line
@@ -5,6 +5,10 @@ KBUILD_DEFCONFIG := defconfig 


comma = ,



ifdef CONFIG_FUNCTION_TRACER

arch-y += -malways-save-lp -mno-relax

endif



KBUILD_CFLAGS	+= $(call cc-option, -mno-sched-prolog-epilog)

KBUILD_CFLAGS	+= -mcmodel=large

arch/nds32/include/asm/ftrace.h

0 → 100644
+20 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */



#ifndef __ASM_NDS32_FTRACE_H

#define __ASM_NDS32_FTRACE_H



#ifdef CONFIG_FUNCTION_TRACER



#define HAVE_FUNCTION_GRAPH_FP_TEST



#define MCOUNT_ADDR ((unsigned long)(_mcount))

/* mcount call is composed of three instructions:

 * sethi + ori + jral

 */

#define MCOUNT_INSN_SIZE 12



extern void _mcount(unsigned long parent_ip);



#endif /* CONFIG_FUNCTION_TRACER */



#endif /* __ASM_NDS32_FTRACE_H */

arch/nds32/kernel/Makefile

+6 −0
Original line number Diff line number Diff line
@@ -21,3 +21,9 @@ extra-y := head.o vmlinux.lds 




obj-y				+= vdso/



obj-$(CONFIG_FUNCTION_TRACER)   += ftrace.o



ifdef CONFIG_FUNCTION_TRACER

CFLAGS_REMOVE_ftrace.o = $(CC_FLAGS_FTRACE)

endif

arch/nds32/kernel/ftrace.c

0 → 100644
+28 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0



#include <linux/ftrace.h>

#include <linux/uaccess.h>

#include <asm/cacheflush.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)

{

	__asm__ ("");  /* avoid to optimize as pure function */

}



noinline void _mcount(unsigned long parent_ip)

{

	/* save all state by the compiler prologue */



	unsigned long ip = (unsigned long)__builtin_return_address(0);



	if (ftrace_trace_function != ftrace_stub)

		ftrace_trace_function(ip - MCOUNT_INSN_SIZE, parent_ip,

				      NULL, NULL);



	/* restore all state by the compiler epilogue */

}

EXPORT_SYMBOL(_mcount);