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: Michal Simek <monstr@monstr.eu>
This commit is contained in:
Michal Simek 2009-11-16 09:40:14 +01:00
parent a3cd613b2e
commit 2fd7c761a2
6 changed files with 140 additions and 0 deletions

View file

@ -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

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@ -1 +1,15 @@
#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 */

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@ -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

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@ -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)

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@ -0,0 +1,105 @@
/*
* 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;

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@ -18,6 +18,7 @@
#include <linux/io.h>
#include <asm/page.h>
#include <asm/system.h>
#include <linux/ftrace.h>
#include <linux/uaccess.h>
/*
@ -47,3 +48,7 @@ extern void __umodsi3(void);
EXPORT_SYMBOL(__umodsi3);
extern char *_ebss;
EXPORT_SYMBOL_GPL(_ebss);
#ifdef CONFIG_FUNCTION_TRACER
extern void _mcount(void);
EXPORT_SYMBOL(_mcount);
#endif