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| author | Wu Zhangjin <wuzhangjin@gmail.com> | 2009-11-20 15:34:29 +0300 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2009-12-17 04:57:21 +0300 |
| commit | d2bb0762993e11363d8343127516b8fe88f9006f (patch) | |
| tree | f210c4c4b0234a776977e6d2b749384e1d3699c1 /arch/mips/kernel/mcount.S | |
| parent | 8922f79ee56e9dab6fc144defc0bc901ff0a7f8a (diff) | |
| download | linux-d2bb0762993e11363d8343127516b8fe88f9006f.tar.xz | |
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>
Diffstat (limited to 'arch/mips/kernel/mcount.S')
| -rw-r--r-- | arch/mips/kernel/mcount.S | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/arch/mips/kernel/mcount.S b/arch/mips/kernel/mcount.S new file mode 100644 index 000000000000..cebcc3c11305 --- /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 <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) + 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 |