Commit 2fd7c761 authored by Michal Simek's avatar Michal Simek
Browse files

microblaze: ftrace: add static function tracer 



If -pg of gcc is enabled with CONFIG_FUNCTION_TRACER=y. a calling to
_mcount will be inserted into each kernel function. so, there is a
possibility to trace the kernel functions in _mcount.

This patch add the specific _mcount support for static function
tracing. by default, ftrace_trace_function is initialized as
ftrace_stub(an empty function), so, the default _mcount will introduce
very little overhead. after enabling ftrace in user-space, it will jump
to a real tracing function and do static function tracing for us.

Commit message from Wu Zhangjin <wuzhangjin@gmail.com>

Signed-off-by: default avatarMichal Simek <monstr@monstr.eu>
parent a3cd613b

arch/microblaze/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ mainmenu "Linux/Microblaze Kernel Configuration" 
config MICROBLAZE

	def_bool y

	select HAVE_LMB

	select HAVE_FUNCTION_TRACER

	select USB_ARCH_HAS_EHCI

	select ARCH_WANT_OPTIONAL_GPIOLIB

arch/microblaze/include/asm/ftrace.h

+14 −0
Original line number Diff line number Diff line 
#ifndef _ASM_MICROBLAZE_FTRACE

#define _ASM_MICROBLAZE_FTRACE



#ifdef CONFIG_FUNCTION_TRACER



#define MCOUNT_ADDR		((long)(_mcount))

#define MCOUNT_INSN_SIZE	8 /* sizeof mcount call */



#ifndef __ASSEMBLY__

extern void _mcount(void);

extern void ftrace_call_graph(void);

#endif



#endif /* CONFIG_FUNCTION_TRACER */

#endif /* _ASM_MICROBLAZE_FTRACE */

arch/microblaze/kernel/Makefile

+11 −0
Original line number Diff line number Diff line
@@ -2,6 +2,16 @@ 
# Makefile

#



ifdef CONFIG_FUNCTION_TRACER

# Do not trace early boot code and low level code

CFLAGS_REMOVE_timer.o = -pg

CFLAGS_REMOVE_intc.o = -pg

CFLAGS_REMOVE_early_printk.o = -pg

CFLAGS_REMOVE_selfmod.o = -pg

CFLAGS_REMOVE_heartbeat.o = -pg

CFLAGS_REMOVE_ftrace.o = -pg

endif



extra-y := head.o vmlinux.lds



obj-y += exceptions.o \
@@ -17,5 +27,6 @@ obj-$(CONFIG_HEART_BEAT) += heartbeat.o 
obj-$(CONFIG_MODULES)		+= microblaze_ksyms.o module.o

obj-$(CONFIG_MMU)		+= misc.o

obj-$(CONFIG_STACKTRACE)	+= stacktrace.o

obj-$(CONFIG_FUNCTION_TRACER)	+= mcount.o



obj-y	+= entry$(MMU).o

arch/microblaze/kernel/cpu/Makefile

+4 −0
Original line number Diff line number Diff line
@@ -2,6 +2,10 @@ 
# Build the appropriate CPU version support

#



ifdef CONFIG_FUNCTION_TRACER

CFLAGS_REMOVE_cache.o = -pg

endif



EXTRA_CFLAGS += -DCPU_MAJOR=$(CPU_MAJOR) -DCPU_MINOR=$(CPU_MINOR) \

		-DCPU_REV=$(CPU_REV)

arch/microblaze/kernel/mcount.S

0 → 100644
+105 −0
Original line number Diff line number Diff line 
/*

 * Low-level ftrace handling

 *

 * Copyright (C) 2009 Michal Simek <monstr@monstr.eu>

 * Copyright (C) 2009 PetaLogix

 *

 * This file is subject to the terms and conditions of the GNU General

 * Public License. See the file COPYING in the main directory of this

 * archive for more details.

 */



#include <linux/linkage.h>



#define NOALIGN_ENTRY(name)	.globl name; name:



/* FIXME MS: I think that I don't need to save all regs */

#define SAVE_REGS		\

	addik	r1, r1, -120;	\

	swi	r2, r1, 4;	\

	swi	r3, r1, 8;	\

	swi	r4, r1, 12;	\

	swi	r5, r1, 116;	\

	swi	r6, r1, 16;	\

	swi	r7, r1, 20;	\

	swi	r8, r1, 24;	\

	swi	r9, r1, 28;	\

	swi	r10, r1, 32;	\

	swi	r11, r1, 36;	\

	swi	r12, r1, 40;	\

	swi	r13, r1, 44;	\

	swi	r14, r1, 48;	\

	swi	r16, r1, 52;	\

	swi	r17, r1, 56;	\

	swi	r18, r1, 60;	\

	swi	r19, r1, 64;	\

	swi	r20, r1, 68;	\

	swi	r21, r1, 72;	\

	swi	r22, r1, 76;	\

	swi	r23, r1, 80;	\

	swi	r24, r1, 84;	\

	swi	r25, r1, 88;	\

	swi	r26, r1, 92;	\

	swi	r27, r1, 96;	\

	swi	r28, r1, 100;	\

	swi	r29, r1, 104;	\

	swi	r30, r1, 108;	\

	swi	r31, r1, 112;



#define RESTORE_REGS		\

	lwi	r2, r1, 4;	\

	lwi	r3, r1, 8;	\

	lwi	r4, r1, 12;	\

	lwi	r5, r1, 116;	\

	lwi	r6, r1, 16;	\

	lwi	r7, r1, 20;	\

	lwi	r8, r1, 24;	\

	lwi	r9, r1, 28;	\

	lwi	r10, r1, 32;	\

	lwi	r11, r1, 36;	\

	lwi	r12, r1, 40;	\

	lwi	r13, r1, 44;	\

	lwi	r14, r1, 48;	\

	lwi	r16, r1, 52;	\

	lwi	r17, r1, 56;	\

	lwi	r18, r1, 60;	\

	lwi	r19, r1, 64;	\

	lwi	r20, r1, 68;	\

	lwi	r21, r1, 72;	\

	lwi	r22, r1, 76;	\

	lwi	r23, r1, 80;	\

	lwi	r24, r1, 84;	\

	lwi	r25, r1, 88;	\

	lwi	r26, r1, 92;	\

	lwi	r27, r1, 96;	\

	lwi	r28, r1, 100;	\

	lwi	r29, r1, 104;	\

	lwi	r30, r1, 108;	\

	lwi	r31, r1, 112;	\

	addik	r1, r1, 120;



ENTRY(ftrace_stub)

	rtsd	r15, 8;

	nop;



ENTRY(_mcount)

	SAVE_REGS

	swi	r15, r1, 0;

	/* MS: test function trace if is taken or not */

	lwi	r20, r0, ftrace_trace_function;

	addik	r6, r0, ftrace_stub;

	cmpu	r5, r20, r6; /* ftrace_trace_function != ftrace_stub */

	beqid	r5, end; /* MS: not taken -> jump over */

	nop;

/* static normal trace */

	lwi	r6, r1, 120; /* MS: load parent addr */

	addik	r5, r15, 0; /* MS: load current function addr */

	/* MS: here is dependency on previous code */

	brald	r15, r20; /* MS: jump to ftrace handler */

	nop;

end:

	lwi	r15, r1, 0;

	RESTORE_REGS



	rtsd	r15, 8; /* MS: jump back */

	nop;