linux-kernel - [PATCH 32/42] tools/nolibc: move exported functions to their own section

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Date:   Mon,  7 Feb 2022 17:23:44 +0100
From:   Willy Tarreau <w@....eu>
To:     "Paul E . McKenney" <paulmck@...nel.org>
Cc:     Mark Brown <broonie@...nel.org>, linux-kernel@...r.kernel.org,
        Willy Tarreau <w@....eu>
Subject: [PATCH 32/42] tools/nolibc: move exported functions to their own section

Some functions like raise() and memcpy() are permanently exported because
they're needed by libgcc on certain platforms. However most of the time
they are not needed and needlessly take space.

Let's move them to their own sub-section, called .text.nolibc_<function>.
This allows ld to get rid of them if unused when passed --gc-sections.

Signed-off-by: Willy Tarreau <w@....eu>
---
 tools/include/nolibc/stdlib.h | 2 +-
 tools/include/nolibc/string.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/include/nolibc/stdlib.h b/tools/include/nolibc/stdlib.h
index 4cc1fdf6791e..da08ff30c15a 100644
--- a/tools/include/nolibc/stdlib.h
+++ b/tools/include/nolibc/stdlib.h
@@ -314,7 +314,7 @@ int msleep(unsigned int msecs)
 }
 
 /* This one is not marked static as it's needed by libgcc for divide by zero */
-__attribute__((weak,unused))
+__attribute__((weak,unused,section(".text.nolibc_raise")))
 int raise(int signal)
 {
 	return sys_kill(sys_getpid(), signal);
diff --git a/tools/include/nolibc/string.h b/tools/include/nolibc/string.h
index c550c9ba8f4c..c1661589cb3c 100644
--- a/tools/include/nolibc/string.h
+++ b/tools/include/nolibc/string.h
@@ -69,7 +69,7 @@ void *memmove(void *dst, const void *src, size_t len)
 }
 
 /* must be exported, as it's used by libgcc on ARM */
-__attribute__((weak,unused))
+__attribute__((weak,unused,section(".text.nolibc_memcpy")))
 void *memcpy(void *dst, const void *src, size_t len)
 {
 	return _nolibc_memcpy_up(dst, src, len);
-- 
2.35.1