From: Namhyung Kim <namhyung@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: x86@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>,
"H. Peter Anvin" <hpa@linux.intel.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH] ftrace/x86: Add comment on static function tracing
Date: Tue, 17 Nov 2015 09:43:24 +0900 [thread overview]
Message-ID: <1447721004-2551-1-git-send-email-namhyung@kernel.org> (raw)
There was a confusion between update_ftrace_function() and static
function tracing trampoline regarding 3rd parameter (ftrace_ops).
Add a comment for clarification.
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
arch/x86/kernel/mcount_64.S | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/x86/kernel/mcount_64.S b/arch/x86/kernel/mcount_64.S
index 94ea120fa21f..87e1762e2bca 100644
--- a/arch/x86/kernel/mcount_64.S
+++ b/arch/x86/kernel/mcount_64.S
@@ -278,6 +278,12 @@ GLOBAL(ftrace_stub)
/* save_mcount_regs fills in first two parameters */
save_mcount_regs
+ /*
+ * When DYNAMIC_FTRACE is not defined, ARCH_SUPPORTS_FTRACE_OPS is not
+ * set (see include/asm/ftrace.h and include/linux/ftrace.h). Only the
+ * ip and parent ip are used and the list function is called when
+ * function tracing is enabled.
+ */
call *ftrace_trace_function
restore_mcount_regs
--
2.6.2
next reply other threads:[~2015-11-17 0:43 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-17 0:43 Namhyung Kim [this message]
2015-11-17 2:03 ` [PATCH] ftrace/x86: Add comment on static function tracing Steven Rostedt
2015-11-19 10:12 ` [tip:x86/urgent] x86/ftrace: " tip-bot for Namhyung Kim
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