Hi Arnd,
On Mon, 19 Nov 2018 at 21:22, Arnd Bergmann arnd@arndb.de wrote:
On Thu, Nov 15, 2018 at 7:14 AM Firoz Khan firoz.khan@linaro.org wrote:
The 2nd option will be the recommended one. For that, I added the __NR_syscalls macro in uapi/asm/unistd.h along with __NR_Linux_syscalls. The macro __NR_syscalls also added for making the name convention same across all architecture. While __NR_syscalls isn't strictly part of the uapi, having it as part of the generated header to simplifies the implementation. We also need to enclose this macro with #ifdef __KERNEL__ to avoid side effects.
I fear this doesn't work the way you hoped:
--- a/arch/mips/include/uapi/asm/unistd.h +++ b/arch/mips/include/uapi/asm/unistd.h @@ -391,16 +391,19 @@ #define __NR_rseq (__NR_Linux + 367) #define __NR_io_pgetevents (__NR_Linux + 368)
+#ifdef __KERNEL__ +#define __NR_syscalls 368 +#endif
We now have three different definitions of __NR_syscalls, one for each ABI. User space previously saw the correct one (now it doesn't see any, but that's ok).
/*
- Offset of the last Linux o32 flavoured syscall
*/ -#define __NR_Linux_syscalls 368 +#define __NR_Linux_syscalls __NR_syscalls
so this part part again is ok.
#endif /* _MIPS_SIM == _MIPS_SIM_ABI32 */
#define __NR_O32_Linux 4000 -#define __NR_O32_Linux_syscalls 368 +#define __NR_O32_Linux_syscalls __NR_syscalls
but this part is not: Now __NR_O32_Linux_syscalls is defined to __NR_syscalls, which may be one of the three values. Any usage of __NR_O32_Linux_syscalls in a 64-bit kernel is then clearly wrong.
#endif /* _MIPS_SIM == _MIPS_SIM_NABI32 */
#define __NR_N32_Linux 6000 -#define __NR_N32_Linux_syscalls 332 +#define __NR_N32_Linux_syscalls __NR_syscalls
Same for this one.
Thanks for the feedback. Will address all the comments.
Firoz
Arnd