Hello all;
After quite some effort investigation and discussion on the crossgcc
mailing group.
I decided to bring my problem here.
I am trying to compile a kernel module for a mips32 chip.
I am having problems with the <asm/uaccess.h> (asm-mips/uaccess) inline
assembly routines for both get_user() and put_user().
Both of these generate inline assembly. In specific a line:
j 2b
My mips compiler does not like this very much and complains loudly:
/tmp/ccw6NzZv.s: Assembler messages:
/tmp/ccw6NzZv.s:128: Error: Cannot branch to symbol in another
section.
Is this a correct MIPS32 instruction? It doesn't seem to be according
to the ISA.
This program seems to compile FINE on x86 since the x86 assembly seems
to have been re-written and put in arch/i386/lib/getuser.S and the
functions __get_user() in <asm-x86/uaccess.h> seems to be obsolete.
I have included a sample module using one of these calls to demonstrate
the problem. I have tried several different cross-compilers and one
native mips compiler all giving the same complaint on the "j 2b"
instruction.
I am definitely NOT a mips assembly expert, but have done my best to
track down the problem and give a sample program.
Any help would be much appreciated.
Cheers,
-=chris
x86 -> x86: (works)
-------------
gcc -I/location_of_my_kernel_includes -DMODULE -D__KERNEL__ -c
moduletest.c
x86 -> mips: (doesn't work)
-------------
mipsel-unknown-linux-gnu-gcc -I/location_of_my_kernel_includes -DMODULE
-D__KERNEL__ -mips32 -c moduletest.c
mips -> mips: (doesn't work)
-------------
gcc -I/location_of_my_kernel_inclues -mips32 -DMODULE -D__KERNEL__ -c
moduletest.c
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/ppp_channel.h>
int init_module() {
int j=1;
unsigned long data;
int foo = 1024;
data = &foo;
//OFFENDING k_call -> get_user() : See <asm/uaccess.h>
// Generates "j 2b" assembly
get_user(j,(int *)data);
return 0;
}
void cleanup_module() {
}
--
Chris Jones | Software Developer | Sutus, Inc.
t: +1.604.987.8866 x 2204 | e: cjones@xxxxxxxxx
