Hi Michal,
On Tue, 2 Oct 2018 at 12:37, Michal Simek michal.simek@xilinx.com wrote:
On 18.9.2018 08:37, Firoz Khan wrote:
On 9 August 2018 at 12:18, Michal Simek michal.simek@xilinx.com wrote:
On 9.8.2018 07:27, Firoz Khan wrote:
__NR_syscalls macro holds the number of system call exist in this architecture. This macro is currently the part of asm/unistd.h file. We have 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.
Update __NR_syscalls in asm/unistd.h manually by counting the no.of system calls. No need to update __NR_syscalls untill we either add a new system call or delete an existing system call.
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 moved the NR_syscalls macro from asm/unistd.h to uapi/asm/unistd.h. The macro name also 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.
This macro was in unistd.h in past but it was moved out because it was causing problem with strace.
commit 40c2702a02b755e0183b702778331b351f3be20c Author: Michal Simek michal.simek@xilinx.com AuthorDate: Mon Jul 8 09:50:24 2013 +0200 Commit: Michal Simek michal.simek@xilinx.com CommitDate: Wed Jul 10 07:32:09 2013 +0200
microblaze: Move __NR_syscalls from uapiThat's why I don't think this is the right thing to do. I have grepped strace and glibc and none is using this macro that's why I think it shouldn't be exported via uapi.
Thanks for you reply :) Sorry for the delayed response :(
I would like to keep __NR_syscalls macro to uapi header in order to simplify the system call table generation script. Otherwise the __NR_syscalls macro need to update manually. That become a problem.
Please check the below implementation in uapi file make sense? It is an easy workaround to leave __NR_syscalls macro in uapi/asm/unistd.h and enclose it in #ifdef __KERNEL__
... ... #define __NR_pkey_free 397 #define __NR_statx 398
#ifdef __KERNEL__ #define __NR_syscalls 399 #endif ... ...
This should be fine.
Thanks for the confirmation!
- Firoz
M