From d2bb0762993e11363d8343127516b8fe88f9006f Mon Sep 17 00:00:00 2001 From: Wu Zhangjin Date: Fri, 20 Nov 2009 20:34:29 +0800 Subject: MIPS: Tracing: Add static function tracer support for MIPS 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 MIPS 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. and -ffunction-sections is incompatible with -pg, so, disable it when ftracer is enabled. Signed-off-by: Wu Zhangjin Reviewed-by: Steven Rostedt Cc: Nicholas Mc Guire Cc: zhangfx@lemote.com Cc: Wu Zhangjin Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Frederic Weisbecker Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Patchwork: http://patchwork.linux-mips.org/patch/672/ Signed-off-by: Ralf Baechle --- arch/mips/Kconfig | 1 + arch/mips/Makefile | 2 + arch/mips/include/asm/ftrace.h | 25 ++++++++++++- arch/mips/kernel/Makefile | 6 +++ arch/mips/kernel/mcount.S | 83 ++++++++++++++++++++++++++++++++++++++++++ arch/mips/kernel/mips_ksyms.c | 5 +++ 6 files changed, 121 insertions(+), 1 deletion(-) create mode 100644 arch/mips/kernel/mcount.S (limited to 'arch') diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index 435838ec959..632dba2ac30 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -5,6 +5,7 @@ config MIPS select HAVE_IDE select HAVE_OPROFILE select HAVE_ARCH_KGDB + select HAVE_FUNCTION_TRACER # Horrible source of confusion. Die, die, die ... select EMBEDDED select RTC_LIB if !MACH_LOONGSON diff --git a/arch/mips/Makefile b/arch/mips/Makefile index 0a7e6146bb4..3725ee923d0 100644 --- a/arch/mips/Makefile +++ b/arch/mips/Makefile @@ -48,7 +48,9 @@ ifneq ($(SUBARCH),$(ARCH)) endif endif +ifndef CONFIG_FUNCTION_TRACER cflags-y := -ffunction-sections +endif cflags-y += $(call cc-option, -mno-check-zero-division) ifdef CONFIG_32BIT diff --git a/arch/mips/include/asm/ftrace.h b/arch/mips/include/asm/ftrace.h index 40a8c178f10..5f8ebcf9fa6 100644 --- a/arch/mips/include/asm/ftrace.h +++ b/arch/mips/include/asm/ftrace.h @@ -1 +1,24 @@ -/* empty */ +/* + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive for + * more details. + * + * Copyright (C) 2009 DSLab, Lanzhou University, China + * Author: Wu Zhangjin + */ + +#ifndef _ASM_MIPS_FTRACE_H +#define _ASM_MIPS_FTRACE_H + +#ifdef CONFIG_FUNCTION_TRACER + +#define MCOUNT_ADDR ((unsigned long)(_mcount)) +#define MCOUNT_INSN_SIZE 4 /* sizeof mcount call */ + +#ifndef __ASSEMBLY__ +extern void _mcount(void); +#define mcount _mcount + +#endif /* __ASSEMBLY__ */ +#endif /* CONFIG_FUNCTION_TRACER */ +#endif /* _ASM_MIPS_FTRACE_H */ diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile index f442de804d8..1340ba3dd38 100644 --- a/arch/mips/kernel/Makefile +++ b/arch/mips/kernel/Makefile @@ -10,6 +10,10 @@ obj-y += cpu-probe.o branch.o entry.o genex.o irq.o process.o \ ptrace.o reset.o setup.o signal.o syscall.o \ time.o topology.o traps.o unaligned.o watch.o +ifdef CONFIG_FUNCTION_TRACER +CFLAGS_REMOVE_early_printk.o = -pg +endif + obj-$(CONFIG_CEVT_BCM1480) += cevt-bcm1480.o obj-$(CONFIG_CEVT_R4K_LIB) += cevt-r4k.o obj-$(CONFIG_MIPS_MT_SMTC) += cevt-smtc.o @@ -27,6 +31,8 @@ obj-$(CONFIG_SYNC_R4K) += sync-r4k.o obj-$(CONFIG_STACKTRACE) += stacktrace.o obj-$(CONFIG_MODULES) += mips_ksyms.o module.o +obj-$(CONFIG_FUNCTION_TRACER) += mcount.o + obj-$(CONFIG_CPU_LOONGSON2) += r4k_fpu.o r4k_switch.o obj-$(CONFIG_CPU_MIPS32) += r4k_fpu.o r4k_switch.o obj-$(CONFIG_CPU_MIPS64) += r4k_fpu.o r4k_switch.o diff --git a/arch/mips/kernel/mcount.S b/arch/mips/kernel/mcount.S new file mode 100644 index 00000000000..cebcc3c1130 --- /dev/null +++ b/arch/mips/kernel/mcount.S @@ -0,0 +1,83 @@ +/* + * MIPS specific _mcount support + * + * 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. + * + * Copyright (C) 2009 Lemote Inc. & DSLab, Lanzhou University, China + * Author: Wu Zhangjin + */ + +#include +#include +#include + + .text + .set noreorder + .set noat + + .macro MCOUNT_SAVE_REGS + PTR_SUBU sp, PT_SIZE + PTR_S ra, PT_R31(sp) + PTR_S AT, PT_R1(sp) + PTR_S a0, PT_R4(sp) + PTR_S a1, PT_R5(sp) + PTR_S a2, PT_R6(sp) + PTR_S a3, PT_R7(sp) +#ifdef CONFIG_64BIT + PTR_S a4, PT_R8(sp) + PTR_S a5, PT_R9(sp) + PTR_S a6, PT_R10(sp) + PTR_S a7, PT_R11(sp) +#endif + .endm + + .macro MCOUNT_RESTORE_REGS + PTR_L ra, PT_R31(sp) + PTR_L AT, PT_R1(sp) + PTR_L a0, PT_R4(sp) + PTR_L a1, PT_R5(sp) + PTR_L a2, PT_R6(sp) + PTR_L a3, PT_R7(sp) +#ifdef CONFIG_64BIT + PTR_L a4, PT_R8(sp) + PTR_L a5, PT_R9(sp) + PTR_L a6, PT_R10(sp) + PTR_L a7, PT_R11(sp) +#endif +#ifdef CONFIG_64BIT + PTR_ADDIU sp, PT_SIZE +#else + PTR_ADDIU sp, (PT_SIZE + 8) +#endif +.endm + + .macro RETURN_BACK + jr ra + move ra, AT + .endm + +NESTED(_mcount, PT_SIZE, ra) + PTR_LA t0, ftrace_stub + PTR_L t1, ftrace_trace_function /* Prepare t1 for (1) */ + bne t0, t1, static_trace + nop + b ftrace_stub + nop + +static_trace: + MCOUNT_SAVE_REGS + + move a0, ra /* arg1: next ip, selfaddr */ + jalr t1 /* (1) call *ftrace_trace_function */ + move a1, AT /* arg2: the caller's next ip, parent */ + + MCOUNT_RESTORE_REGS + .globl ftrace_stub +ftrace_stub: + RETURN_BACK + END(_mcount) + + .set at + .set reorder diff --git a/arch/mips/kernel/mips_ksyms.c b/arch/mips/kernel/mips_ksyms.c index 225755d0c1f..1d04807874d 100644 --- a/arch/mips/kernel/mips_ksyms.c +++ b/arch/mips/kernel/mips_ksyms.c @@ -13,6 +13,7 @@ #include #include #include +#include extern void *__bzero(void *__s, size_t __count); extern long __strncpy_from_user_nocheck_asm(char *__to, @@ -51,3 +52,7 @@ EXPORT_SYMBOL(csum_partial_copy_nocheck); EXPORT_SYMBOL(__csum_partial_copy_user); EXPORT_SYMBOL(invalid_pte_table); +#ifdef CONFIG_FUNCTION_TRACER +/* _mcount is defined in arch/mips/kernel/mcount.S */ +EXPORT_SYMBOL(_mcount); +#endif -- cgit v1.2.3