[PATCH v2 2/7] ia64: replace NR_syscalls macro from asm/unistd.h

From: Firoz Khan <firoz.khan@linaro.org>
To: linux-ia64@vger.kernel.org, Tony Luck <tony.luck@intel.com>,
	Fenghua Yu <fenghua.yu@intel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Philippe Ombredanne <pombredanne@nexb.com>,
	Kate Stewart <kstewart@linuxfoundation.org>
Cc: y2038@lists.linaro.org, linux-kernel@vger.kernel.org,
	linux-arch@vger.kernel.org, arnd@arndb.de,
	deepa.kernel@gmail.com, marcin.juszkiewicz@linaro.org,
	firoz.khan@linaro.org
Subject: [PATCH v2 2/7] ia64: replace NR_syscalls macro from asm/unistd.h
Date: Thu, 27 Sep 2018 19:45:15 +0530	[thread overview]
Message-ID: <1538057720-3392-3-git-send-email-firoz.khan@linaro.org> (raw)
In-Reply-To: <1538057720-3392-1-git-send-email-firoz.khan@linaro.org>

NR_syscalls macro holds the number of system call exist in IA64
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 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 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 uapi/asm/unistd.h. The macro
name changed form NR_syscalls to __NR_syscalls 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/ia64/include/asm/unistd.h      | 4 +---
 arch/ia64/include/uapi/asm/unistd.h | 4 ++++
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/ia64/include/asm/unistd.h b/arch/ia64/include/asm/unistd.h
index ffb705d..397b143 100644
--- a/arch/ia64/include/asm/unistd.h
+++ b/arch/ia64/include/asm/unistd.h
@@ -10,9 +10,7 @@
 
 #include <uapi/asm/unistd.h>
 
-
-
-#define NR_syscalls			326 /* length of syscall table */
+#define NR_syscalls		__NR_syscalls /* length of syscall table */
 
 /*
  * The following defines stop scripts/checksyscalls.sh from complaining about
diff --git a/arch/ia64/include/uapi/asm/unistd.h b/arch/ia64/include/uapi/asm/unistd.h
index 4d590c9..4186dc2 100644
--- a/arch/ia64/include/uapi/asm/unistd.h
+++ b/arch/ia64/include/uapi/asm/unistd.h
@@ -341,4 +341,8 @@
 #define __NR_preadv2			1348
 #define __NR_pwritev2			1349
 
+#ifdef __KERNEL__
+#define __NR_syscalls			326
+#endif
+
 #endif /* _UAPI_ASM_IA64_UNISTD_H */
-- 
1.9.1

