iw: set retain atrribute on sections

Message ID	20210424003131.2165866-1-manojgupta@google.com
State	New
Headers	show Return-Path: <linux-wireless-owner@kernel.org> Date: Fri, 23 Apr 2021 17:31:31 -0700 In-Reply-To: <20210422182545.726897-1-manojgupta@google.com> Message-Id: <20210424003131.2165866-1-manojgupta@google.com> Mime-Version: 1.0 References: <20210422182545.726897-1-manojgupta@google.com> Subject: [PATCH] iw: set retain atrribute on sections From: Manoj Gupta <manojgupta@google.com> To: Johannes Berg <johannes@sipsolutions.net> Cc: llozano@google.com, manojgupta@google.com, linux-wireless@vger.kernel.org, Fangrui Song <maskray@google.com>, stable@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk
Series	iw: set retain atrribute on sections \| expand iw: set retain atrribute on sections

Message ID

20210424003131.2165866-1-manojgupta@google.com

State

New

Headers

Date: Fri, 23 Apr 2021 17:31:31 -0700
In-Reply-To: <20210422182545.726897-1-manojgupta@google.com>
Message-Id: <20210424003131.2165866-1-manojgupta@google.com>
Mime-Version: 1.0
References: <20210422182545.726897-1-manojgupta@google.com>
Subject: [PATCH] iw: set retain atrribute on sections
From: Manoj Gupta <manojgupta@google.com>
To: Johannes Berg <johannes@sipsolutions.net>
Cc: llozano@google.com, manojgupta@google.com,
	linux-wireless@vger.kernel.org, Fangrui Song <maskray@google.com>,
	stable@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Series

iw: set retain atrribute on sections | expand

Commit Message

Manoj Gupta April 24, 2021, 12:31 a.m. UTC

LLD 13 and GNU ld 2.37 support -z start-stop-gc which allows garbage
collection of C identifier name sections despite the __start_/__stop_
references.  Simply set the retain attribute so that GCC 11 (if
configure-time binutils is 2.36 or newer)/Clang 13 will set the
SHF_GNU_RETAIN section attribute to prevent garbage collection.

Without the patch, there are linker errors like the following with -z
start-stop-gc:
ld.lld: error: undefined symbol: __stop___cmd
>>> referenced by iw.c:418
>>>               iw.o:(__handle_cmd)

Suggested-by: Fangrui Song <maskray@google.com>

Cc: stable@vger.kernel.org

Signed-off-by: Manoj Gupta <manojgupta@google.com>
---
 iw.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/iw.h b/iw.h
index 7f7f4fc..67aa00c 100644
--- a/iw.h
+++ b/iw.h
@@ -118,8 +118,9 @@  struct chandef {
 		.parent = _section,					\
 		.selector = (_sel),					\
 	};								\
+	_Pragma("GCC diagnostic ignored \"-Wattributes\"") 		\
 	static struct cmd *__cmd ## _ ## _symname ## _ ## _handler ## _ ## _nlcmd ## _ ## _idby ## _ ## _hidden ## _p \
-	__attribute__((used,section("__cmd"))) =			\
+	__attribute__((used,retain,section("__cmd"))) =			\
 	&__cmd ## _ ## _symname ## _ ## _handler ## _ ## _nlcmd ## _ ## _idby ## _ ## _hidden
 #define __ACMD(_section, _symname, _name, _args, _nlcmd, _flags, _hidden, _idby, _handler, _help, _sel, _alias)\
 	__COMMAND(_section, _symname, _name, _args, _nlcmd, _flags, _hidden, _idby, _handler, _help, _sel);\

iw: set retain atrribute on sections

Commit Message

Patch