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authorWu Zhangjin <wuzhangjin@gmail.com>2009-11-20 20:34:29 +0800
committerRalf Baechle <ralf@linux-mips.org>2009-12-17 01:57:21 +0000
commitd2bb0762993e11363d8343127516b8fe88f9006f (patch)
treef210c4c4b0234a776977e6d2b749384e1d3699c1 /arch/mips/include/asm/ftrace.h
parent8922f79ee56e9dab6fc144defc0bc901ff0a7f8a (diff)
downloadlinux-2.6.34-ux500-d2bb0762993e11363d8343127516b8fe88f9006f.tar.gz
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/include/asm/ftrace.h')
-rw-r--r--arch/mips/include/asm/ftrace.h25
1 files changed, 24 insertions, 1 deletions
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 <wuzj@lemote.com>
+ */
+
+#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 */