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From: Arnd Bergmann <>
To: Steven Rostedt <>,
	Ingo Molnar <>,
	Thomas Gleixner <>,
	Borislav Petkov <>,
Cc: Arnd Bergmann <>, "H. Peter Anvin" <>,
	Masami Hiramatsu <>,
Subject: [PATCH] x86/ftrace: avoid an unused-function warning
Date: Mon,  4 Mar 2019 21:07:39 +0100
Message-ID: <> (raw)

Depending on the configuration, ftrace_jmp_replace() sometimes
has no callers at all, since one of the users was removed:

arch/x86/kernel/ftrace.c:669:23: error: 'ftrace_jmp_replace' defined but not used [-Werror=unused-function]

Rather than trying to figure out the correct #ifdef check for this
time, just mark it __maybe_unused and let the compiler drop it

Fixes: d2a68c4effd8 ("x86/ftrace: Do not call function graph from dynamic trampolines")
Signed-off-by: Arnd Bergmann <>
 arch/x86/kernel/ftrace.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 3e3789c8f8e1..905056240411 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -665,8 +665,7 @@ int __init ftrace_dyn_arch_init(void)
 	return 0;
-#if defined(CONFIG_X86_64) || defined(CONFIG_FUNCTION_GRAPH_TRACER)
-static unsigned char *ftrace_jmp_replace(unsigned long ip, unsigned long addr)
+static __maybe_unused unsigned char *ftrace_jmp_replace(unsigned long ip, unsigned long addr)
 	static union ftrace_code_union calc;
@@ -679,7 +678,6 @@ static unsigned char *ftrace_jmp_replace(unsigned long ip, unsigned long addr)
 	return calc.code;
 /* Currently only x86_64 supports dynamic trampolines */
 #ifdef CONFIG_X86_64

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Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-04 20:07 Arnd Bergmann [this message]
2019-03-04 21:43 ` Steven Rostedt
2019-03-05  7:52   ` Arnd Bergmann

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