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Date:   Fri, 02 Apr 2021 12:40:08 +0000
To:     Kees Cook <keescook@chromium.org>
From:   Alexander Lobakin <alobakin@pm.me>
Cc:     Jessica Yu <jeyu@kernel.org>, Miroslav Benes <mbenes@suse.cz>,
        Emil Velikov <emil.l.velikov@gmail.com>,
        Sami Tolvanen <samitolvanen@google.com>,
        Sean Christopherson <seanjc@google.com>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Alexander Lobakin <alobakin@pm.me>,
        linux-hardening@vger.kernel.org, linux-kbuild@vger.kernel.org,
        linux-kernel@vger.kernel.org
Reply-To: Alexander Lobakin <alobakin@pm.me>
Subject: [PATCH] kbuild: merge module sections under CONFIG_LD_DEAD_CODE_DATA_ELIMINATION too
Message-ID: <20210402123959.5143-1-alobakin@pm.me>
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Precedence: bulk

When building with CONFIG_LD_DEAD_CODE_DATA_ELIMINATION,
-fdata-sections and -ffunction-sections are being enabled by the
top-level Makefile, and module section merging is also needed.
Expand the ifdef (and the comment block) to cover that case too.

Fixes: 6a3193cdd5e5 ("kbuild: lto: Merge module sections if and only if CON=
FIG_LTO_CLANG is enabled")
Signed-off-by: Alexander Lobakin <alobakin@pm.me>
---
 scripts/module.lds.S | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/scripts/module.lds.S b/scripts/module.lds.S
index 2c52535f9b56..d6bbdfc55e08 100644
--- a/scripts/module.lds.S
+++ b/scripts/module.lds.S
@@ -20,11 +20,14 @@ SECTIONS {

 =09__patchable_function_entries : { *(__patchable_function_entries) }

-#ifdef CONFIG_LTO_CLANG
+#if defined(CONFIG_LD_DEAD_CODE_DATA_ELIMINATION) || defined(CONFIG_LTO_CL=
ANG)
 =09/*
 =09 * With CONFIG_LTO_CLANG, LLD always enables -fdata-sections and
-=09 * -ffunction-sections, which increases the size of the final module.
-=09 * Merge the split sections in the final binary.
+=09 * -ffunction-sections. With CONFIG_LD_DEAD_CODE_DATA_ELIMINATION,
+=09 * -fdata-sections and -ffunction-sections are being enabled by
+=09 * the top-level Makefile.
+=09 * This increases the size of the final module. Merge the split
+=09 * sections in the final binary.
 =09 */
 =09.bss : {
 =09=09*(.bss .bss.[0-9a-zA-Z_]*)
--
2.31.1