Re: [PATCH/RFC] m68k: Add -ffreestanding to KBUILD_CFLAGS

Michal Marek
2013-04-10T15:22:32Z

On Wed, Apr 10, 2013 at 04:19:14PM +0200, Geert Uytterhoeven wrote:
> Thanks for the patch, but modpost still fails with
>
> ERROR: "strlen" [net/ipv4/ip_tunnel.ko] undefined!

OK OK, I am convinced. Then how about this? If you prefer speed over
size, the the other option is to add

size_t strlen(const char *s)
{
return __kernel_strlen(s);
}
EXPORT_SYMBOL(strlen);

to arch/m68k/lib/string.c. On a related note, arch/m68k/lib/string.c is
built only in the CONFIG_MMU case, whereas asm/string.h is shared.

Michal

From 1b89666d246bcc2bfc4c9e1bdfd1dbd1dafe2e2f Mon Sep 17 00:00:00 2001
From: Michal Marek <mmarek@suse.cz>
Date: Wed, 10 Apr 2013 16:45:21 +0200
Subject: [PATCH] m68k: Remove inline strlen() implementation

GCC can replace a strncat() call with constant second argument into a
strlen + store, which results in a link error:

ERROR: "strlen" [net/ipv4/ip_tunnel.ko] undefined!

The inline function is a simple for loop in C. Other architectures
either use an asm optimized variant, or use the generic function from
lib/string.c.

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>
---
arch/m68k/include/asm/string.h | 14 --------------
arch/m68k/lib/string.c | 2 +-
2 files changed, 1 insertion(+), 15 deletions(-)

diff --git a/arch/m68k/include/asm/string.h b/arch/m68k/include/asm/string.h
index 3219845..9aea9f1 100644
--- a/arch/m68k/include/asm/string.h
+++ b/arch/m68k/include/asm/string.h
@@ -4,15 +4,6 @@
#include <linux/types.h>
#include <linux/compiler.h>

-static inline size_t __kernel_strlen(const char *s)
-{
- const char *sc;
-
- for (sc = s; *sc++; )
- ;
- return sc - s - 1;
-}
-
static inline char *__kernel_strcpy(char *dest, const char *src)
{
char *xdest = dest;
@@ -27,11 +18,6 @@ static inline char *__kernel_strcpy(char *dest, const char *src)

#ifndef __IN_STRING_C

-#define __HAVE_ARCH_STRLEN
-#define strlen(s) (__builtin_constant_p(s) ? \
- __builtin_strlen(s) : \
- __kernel_strlen(s))
-
#define __HAVE_ARCH_STRNLEN
static inline size_t strnlen(const char *s, size_t count)
{
diff --git a/arch/m68k/lib/string.c b/arch/m68k/lib/string.c
index b9a57ab..4d61fa8 100644
--- a/arch/m68k/lib/string.c
+++ b/arch/m68k/lib/string.c
@@ -17,6 +17,6 @@ EXPORT_SYMBOL(strcpy);

char *strcat(char *dest, const char *src)
{
- return __kernel_strcpy(dest + __kernel_strlen(dest), src);
+ return __kernel_strcpy(dest + strlen(dest), src);
}
EXPORT_SYMBOL(strcat);
--
1.7.10.4