[PATCH v6 1/5] powerpc: add __NR_syscalls along with NR_syscalls

From: Firoz Khan
Date: Mon Dec 17 2018 - 05:41:25 EST

NR_syscalls macro holds the number of system call exist
in powerpc architecture. We have to change the value of
NR_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 number of system call
information. So we have two option to update NR_syscalls

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

2. We can keep this feature in 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_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_syscalls asm/unistd.h. 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@xxxxxxxxxx>
arch/powerpc/include/asm/unistd.h | 3 +--
arch/powerpc/include/uapi/asm/unistd.h | 5 ++++-
2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/include/asm/unistd.h b/arch/powerpc/include/asm/unistd.h
index b0de85b..a3c35e6 100644
--- a/arch/powerpc/include/asm/unistd.h
+++ b/arch/powerpc/include/asm/unistd.h
@@ -11,8 +11,7 @@

#include <uapi/asm/unistd.h>

-#define NR_syscalls 389
+#define NR_syscalls __NR_syscalls

#define __NR__exit __NR_exit

diff --git a/arch/powerpc/include/uapi/asm/unistd.h b/arch/powerpc/include/uapi/asm/unistd.h
index 985534d..7195868 100644
--- a/arch/powerpc/include/uapi/asm/unistd.h
+++ b/arch/powerpc/include/uapi/asm/unistd.h
@@ -10,7 +10,6 @@

#define __NR_restart_syscall 0
#define __NR_exit 1
#define __NR_fork 2
@@ -401,4 +400,8 @@
#define __NR_rseq 387
#define __NR_io_pgetevents 388

+#ifdef __KERNEL__
+#define __NR_syscalls 389