[PATCH v3 1/6] mips: add __NR_syscalls along with __NR_Linux_syscalls

Firoz Khan
2018-11-29T08:44:22Z

__NR_Linux_syscalls macro holds the number of system call
exist in mips architecture. We have to change the value of
__NR_Linux_syscalls, if we add or delete a system call.

One of the patch in this patch series has a script which
will generate a uapi header based on syscall.tbl file.
The syscall.tbl file contains the total number of system
calls information. So we have two option to update __NR-
_Linux_syscalls value.

1. Update __NR_Linux_syscalls in asm/unistd.h manually
by counting the no.of system calls. No need to update
__NR_Linux_syscalls until we either add a new system
call or delete existing system call.

2. We can keep this feature it above mentioned script,
that will count the number of syscalls and keep it in
a generated file. In this case we don't need to expli-
citly update __NR_Linux_syscalls in asm/unistd.h file.

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.

Signed-off-by: Firoz Khan <firoz.khan@linaro.org>
---
arch/mips/include/uapi/asm/unistd.h | 17 ++++++++++++++---
1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/arch/mips/include/uapi/asm/unistd.h b/arch/mips/include/uapi/asm/unistd.h
index f25dd1d..6914be5 100644
--- a/arch/mips/include/uapi/asm/unistd.h
+++ b/arch/mips/include/uapi/asm/unistd.h
@@ -391,11 +391,14 @@
#define __NR_rseq (__NR_Linux + 367)
#define __NR_io_pgetevents (__NR_Linux + 368)

+#ifdef __KERNEL__
+#define __NR_syscalls 368
+#endif

/*
* Offset of the last Linux o32 flavoured syscall
*/
-#define __NR_Linux_syscalls 368
+#define __NR_Linux_syscalls __NR_syscalls

#endif /* _MIPS_SIM == _MIPS_SIM_ABI32 */

@@ -738,10 +741,14 @@
#define __NR_rseq (__NR_Linux + 327)
#define __NR_io_pgetevents (__NR_Linux + 328)

+#ifdef __KERNEL__
+#define __NR_syscalls 328
+#endif
+
/*
* Offset of the last Linux 64-bit flavoured syscall
*/
-#define __NR_Linux_syscalls 328
+#define __NR_Linux_syscalls __NR_syscalls

#endif /* _MIPS_SIM == _MIPS_SIM_ABI64 */

@@ -1088,10 +1095,14 @@
#define __NR_rseq (__NR_Linux + 331)
#define __NR_io_pgetevents (__NR_Linux + 332)

+#ifdef __KERNEL__
+#define __NR_syscalls 332
+#endif
+
/*
* Offset of the last N32 flavoured syscall
*/
-#define __NR_Linux_syscalls 332
+#define __NR_Linux_syscalls __NR_syscalls

#endif /* _MIPS_SIM == _MIPS_SIM_NABI32 */

--
1.9.1