如何给MIPS架构的kernel添加系统调用

首先在arch/mips模块里添加新系统调用getposition的实现：

arch/mips/kernel/scall32-o32.S

sys sys_ni_syscall 0

sys sys_ni_syscall 0

sys sys_ni_syscall 0

sys sys_ioprio_set 3

sys sys_ioprio_get 2 /* 4315 */

+ sys sys_getposition 0 /* 4316 */

.endm

arch/mips/kernel/syscall.c

+ asmlinkage int sys_getposition()

+ {

+ return 0;

+ }

然后在头文件里给系统调用分配调用号：

include/asm-mips/unistd.h

#define __NR_ioprio_set (__NR_Linux + 314)

#define __NR_ioprio_get (__NR_Linux + 315)

+ #define __NR_getposition (__NR_Linux + 316)

/*

* Offset of the last Linux o32 flavoured syscall

*/

- #define __NR_Linux_syscalls 315

+ #define __NR_Linux_syscalls 316

#endif /* _MIPS_SIM == _MIPS_SIM_ABI32 */

#define __NR_O32_Linux 4000

- #define __NR_O32_Linux_syscalls 315

+ #define __NR_O32_Linux_syscalls 316

编译内核。。。。

完成后，测试新的系统调用：

test.c

#include <linux/unistd.h>

_syscall0(int, getposition)

int main()

{

int i = getposition();

...

return 0;

}

完成！