All of lore.kernel.org
 help / color / mirror / Atom feed
From: Nicholas Piggin <npiggin@gmail.com>
To: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Nicholas Piggin <npiggin@gmail.com>,
	linux-arch@vger.kernel.org, linux-kbuild@vger.kernel.org,
	linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v2 2/4] kbuild: LD_DEAD_CODE_DATA_ELIMINATION no -ffunction-sections/-fdata-sections for module build
Date: Wed,  9 May 2018 22:59:59 +1000	[thread overview]
Message-ID: <20180509130001.24276-3-npiggin@gmail.com> (raw)
In-Reply-To: <20180509130001.24276-1-npiggin@gmail.com>

Modules do not tend to cope with -ffunction-sections, even though they
do not link with -gc-sections. It may be possible for unused symbols to
be trimmed from modules, but in general that would take much more work
in architecture module linker scripts.

For now, enable these only for kernel build.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 Makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index 619a85ad716b..9dcbfb353f81 100644
--- a/Makefile
+++ b/Makefile
@@ -799,8 +799,8 @@ KBUILD_CFLAGS += $(call cc-option, -fno-inline-functions-called-once)
 endif
 
 ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION
-KBUILD_CFLAGS	+= $(call cc-option,-ffunction-sections,)
-KBUILD_CFLAGS	+= $(call cc-option,-fdata-sections,)
+KBUILD_CFLAGS_KERNEL	+= $(call cc-option,-ffunction-sections,)
+KBUILD_CFLAGS_KERNEL	+= $(call cc-option,-fdata-sections,)
 endif
 
 # arch Makefile may override CC so keep this after arch Makefile is included
-- 
2.17.0


WARNING: multiple messages have this Message-ID (diff)
From: Nicholas Piggin <npiggin@gmail.com>
To: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: linux-arch@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	Nicholas Piggin <npiggin@gmail.com>,
	linux-kbuild@vger.kernel.org
Subject: [PATCH v2 2/4] kbuild: LD_DEAD_CODE_DATA_ELIMINATION no -ffunction-sections/-fdata-sections for module build
Date: Wed,  9 May 2018 22:59:59 +1000	[thread overview]
Message-ID: <20180509130001.24276-3-npiggin@gmail.com> (raw)
In-Reply-To: <20180509130001.24276-1-npiggin@gmail.com>

Modules do not tend to cope with -ffunction-sections, even though they
do not link with -gc-sections. It may be possible for unused symbols to
be trimmed from modules, but in general that would take much more work
in architecture module linker scripts.

For now, enable these only for kernel build.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 Makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index 619a85ad716b..9dcbfb353f81 100644
--- a/Makefile
+++ b/Makefile
@@ -799,8 +799,8 @@ KBUILD_CFLAGS += $(call cc-option, -fno-inline-functions-called-once)
 endif
 
 ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION
-KBUILD_CFLAGS	+= $(call cc-option,-ffunction-sections,)
-KBUILD_CFLAGS	+= $(call cc-option,-fdata-sections,)
+KBUILD_CFLAGS_KERNEL	+= $(call cc-option,-ffunction-sections,)
+KBUILD_CFLAGS_KERNEL	+= $(call cc-option,-fdata-sections,)
 endif
 
 # arch Makefile may override CC so keep this after arch Makefile is included
-- 
2.17.0

  parent reply	other threads:[~2018-05-09 13:00 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-09 12:59 [PATCH v2 0/4] LD_DEAD_CODE_DATA_ELIMINATION fixes and enabling for powerpc Nicholas Piggin
2018-05-09 12:59 ` Nicholas Piggin
2018-05-09 12:59 ` [PATCH v2 1/4] kbuild: Fix asm-generic/vmlinux.lds.h for LD_DEAD_CODE_DATA_ELIMINATION Nicholas Piggin
2018-05-09 12:59   ` Nicholas Piggin
2018-05-09 12:59 ` Nicholas Piggin [this message]
2018-05-09 12:59   ` [PATCH v2 2/4] kbuild: LD_DEAD_CODE_DATA_ELIMINATION no -ffunction-sections/-fdata-sections for module build Nicholas Piggin
2018-05-09 13:00 ` [PATCH v2 3/4] kbuild: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selectable if enabled Nicholas Piggin
2018-05-09 13:00   ` Nicholas Piggin
2018-05-09 13:00 ` [PATCH v2 4/4] powerpc: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selected Nicholas Piggin
2018-05-09 13:00   ` Nicholas Piggin
2018-05-14  2:05   ` Michael Ellerman
2018-05-14  2:05     ` Michael Ellerman
2018-05-14  2:05     ` Michael Ellerman
2018-05-14  6:06   ` Mathieu Malaterre
2018-05-14  6:06     ` Mathieu Malaterre
2018-05-14  0:08 ` [PATCH v2 0/4] LD_DEAD_CODE_DATA_ELIMINATION fixes and enabling for powerpc Masahiro Yamada
2018-05-14  0:08   ` Masahiro Yamada

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20180509130001.24276-3-npiggin@gmail.com \
    --to=npiggin@gmail.com \
    --cc=linux-arch@vger.kernel.org \
    --cc=linux-kbuild@vger.kernel.org \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=yamada.masahiro@socionext.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.