Patch from Christophe Massiot:

    Hello,

    When using uClibc to compile the modutils for a MIPS target, the linker
    outputs an "undefined symbol: _flush_cache". After some digging, it's
    a syscall only available on the MIPS architecture, and the _flush_cache
    symbol is in the GNU libc.

    Attached patch defines it in uClibc as well. I'm not sure if I made it
    the right way, though, but it works for me.

libc/sysdeps/linux/mips/Makefile

@@ -26,7 +26,7 @@ CRT0_OBJ = crt0.o crt1.o
 SSRC=bsd-_setjmp.S bsd-setjmp.S setjmp.S clone.S fork.S syscall.S
 SOBJS=$(patsubst %.S,%.o, $(SSRC))
 
-CSRC=__longjmp.c  brk.c vfork.c setjmp_aux.c _mmap.c pipe.c __syscall_error.c
+CSRC=__longjmp.c  brk.c vfork.c setjmp_aux.c _mmap.c pipe.c __syscall_error.c cacheflush.c
 COBJS=$(patsubst %.c,%.o, $(CSRC))
 
 OBJS=$(SOBJS) $(MOBJ) $(COBJS)

libc/sysdeps/linux/mips/cacheflush.c

@@ -0,0 +1,27 @@
+/* brk system call for Linux/MIPS.
+   Copyright (C) 2000 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <errno.h>
+#include <unistd.h>
+#include <sys/syscall.h>
+
+_syscall3(int, cacheflush, void *, addr, const int, nbytes, const int, op);
+weak_alias(cacheflush, _flush_cache)
+_syscall3(int, cachectl, void *, addr, const int, nbytes, const int, op);
+