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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/kernel/mips_ksyms.c
parent8922f79ee56e9dab6fc144defc0bc901ff0a7f8a (diff)
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/mips_ksyms.c')
-rw-r--r--arch/mips/kernel/mips_ksyms.c5
1 files changed, 5 insertions, 0 deletions
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 <asm/checksum.h>
#include <asm/pgtable.h>
#include <asm/uaccess.h>
+#include <asm/ftrace.h>
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