[PATCH v3 2/5] m68k: replace NR_syscalls macro from asm/unistd.h

From: Firoz Khan
Date: Mon Oct 01 2018 - 08:38:52 EST


NR_syscalls macro holds the number of system call exist in m68k
architecture. This macro is currently the part of asm/unistd.h file.
We have to change the value of NR_syscalls, if we add or delete a
system call.

One of 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 value.

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

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

The 2nd option will be the recommended one. For that, I come up
with another macro - __NR_syscalls which will be updated by the
script and it will be present in api/asm/unistd.h. While __NR_syscalls
isn't strictly part of the uapi, having it as part of the generated
header to simplifies the implementation. So we need to enclose this
macro with #ifdef __KERNEL__ to avoid side effects.

Signed-off-by: Firoz Khan <firoz.khan@xxxxxxxxxx>
---
arch/m68k/include/asm/unistd.h | 3 +--
arch/m68k/include/uapi/asm/unistd.h | 4 ++++
2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/m68k/include/asm/unistd.h b/arch/m68k/include/asm/unistd.h
index 30d0d3f..5072e94 100644
--- a/arch/m68k/include/asm/unistd.h
+++ b/arch/m68k/include/asm/unistd.h
@@ -4,8 +4,7 @@

#include <uapi/asm/unistd.h>

-
-#define NR_syscalls 380
+#define NR_syscalls __NR_syscalls

#define __ARCH_WANT_OLD_READDIR
#define __ARCH_WANT_OLD_STAT
diff --git a/arch/m68k/include/uapi/asm/unistd.h b/arch/m68k/include/uapi/asm/unistd.h
index de3054f..ba4176aa 100644
--- a/arch/m68k/include/uapi/asm/unistd.h
+++ b/arch/m68k/include/uapi/asm/unistd.h
@@ -387,4 +387,8 @@
#define __NR_pwritev2 378
#define __NR_statx 379

+#ifdef __KERNEL__
+#define __NR_syscalls 380
+#endif
+
#endif /* _UAPI_ASM_M68K_UNISTD_H_ */
--
1.9.1