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From: Arnd Bergmann <arnd@arndb.de>
To: Masahiro Yamada <yamada.masahiro@socionext.com>,
	Michal Marek <mmarek@suse.com>
Cc: Nicholas Piggin <npiggin@gmail.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Namhyung Kim <namhyung.with.foss@gmail.com>,
	linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] [SUBMITTED 20170314] [v333kbuild: disable -ffunction-sections on gcc-4.7 with ftrace
Date: Tue, 14 Mar 2017 22:37:15 +0100	[thread overview]
Message-ID: <20170314213724.3836900-1-arnd@arndb.de> (raw)
In-Reply-To: <20170314213410.3762842-1-arnd@arndb.de>

When ftrace is enabled and we build with gcc-4.7 or older, we
get a warning for each file on architectures that select
CONFIG_LD_DEAD_CODE_DATA_ELIMINATION:

warning: -ffunction-sections disabled; it makes profiling impossible [enabled by default]

This turns off function sections in that specific case, leaving
it enabled for all other configurations.

Fixes: b67067f1176d ("kbuild: allow archs to select link dead code/data elimination")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Namhyung Kim <namhyung.with.foss@gmail.com>
---
v2: accidentally resend the same patch as before
v3: send the exact same patch once more, without doing the change I wanted
v4: actually fixed version number in check as pointed out by Namhyung Kim (I hope)
---
 Makefile | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Makefile b/Makefile
index 6e7e644a0b84..3a964fa3a787 100644
--- a/Makefile
+++ b/Makefile
@@ -662,7 +662,11 @@ KBUILD_CFLAGS	+= -Wextra
 KBUILD_CFLAGS	+= $(call cc-disable-warning,frame-address,)
 
 ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION
+ifdef CONFIG_FUNCTION_TRACER
+KBUILD_CFLAGS	+= $(call cc-ifversion, -ge,0408,$(call cc-option,-ffunction-sections,))
+else
 KBUILD_CFLAGS	+= $(call cc-option,-ffunction-sections,)
+endif
 KBUILD_CFLAGS	+= $(call cc-option,-fdata-sections,)
 endif
 
-- 
2.9.0

  parent reply	other threads:[~2017-03-14 21:37 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-14 21:33 [PATCH] [v2] kbuild: disable -ffunction-sections on gcc-4.7 with ftrace Arnd Bergmann
2017-03-14 21:35 ` [PATCH] [v333kbuild: " Arnd Bergmann
2017-03-14 21:37 ` Arnd Bergmann [this message]
2017-03-29  2:07   ` [PATCH] [SUBMITTED 20170314] " Masahiro Yamada
2017-03-29  9:30     ` Arnd Bergmann
2017-03-30 15:42       ` Masahiro Yamada
2017-03-31  8:48         ` Arnd Bergmann
     [not found]           ` <CAFzeTN3-=a6n-PEKP5ssCUszYYPu5R5_6uf9DEdptPKEuWOsrQ@mail.gmail.com>
2017-03-31 20:39             ` Arnd Bergmann

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