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linux_old1/arch/mips/kernel/mcount.S

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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 <wuzhangjin@gmail.com> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Cc: Nicholas Mc Guire <der.herr@hofr.at> Cc: zhangfx@lemote.com Cc: Wu Zhangjin <wuzhangjin@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> 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 <ralf@linux-mips.org>
2009-11-20 20:34:29 +08:00
/*
* 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 <wuzj@lemote.com>
*/
#include <asm/regdef.h>
#include <asm/stackframe.h>
#include <asm/ftrace.h>
.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)
MIPS: Tracing: Enable HAVE_FUNCTION_TRACE_MCOUNT_TEST for MIPS There is an exisiting common ftrace_test_stop_func() in kernel/trace/ftrace.c, which is used to check the global variable ftrace_trace_stop to determine whether stop the function tracing. This patch implepment the MIPS specific one to speedup the procedure. Thanks goes to Zhang Le for Cleaning it up. Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Nicholas Mc Guire <der.herr@hofr.at> Cc: zhangfx@lemote.com Cc: Wu Zhangjin <wuzhangjin@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Patchwork: http://patchwork.linux-mips.org/patch/673/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2009-11-20 20:34:30 +08:00
lw t0, function_trace_stop
bnez t0, ftrace_stub
nop
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 <wuzhangjin@gmail.com> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Cc: Nicholas Mc Guire <der.herr@hofr.at> Cc: zhangfx@lemote.com Cc: Wu Zhangjin <wuzhangjin@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> 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 <ralf@linux-mips.org>
2009-11-20 20:34:29 +08:00
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