On 18.9.2018 08:37, Firoz Khan wrote: > On 9 August 2018 at 12:18, Michal Simek <michal.simek@xxxxxxxxxx> 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. >>> >>> 1. 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. >>> >>> 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 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@xxxxxxxxxx> >> AuthorDate: Mon Jul 8 09:50:24 2013 +0200 >> Commit: Michal Simek <michal.simek@xxxxxxxxxx> >> CommitDate: Wed Jul 10 07:32:09 2013 +0200 >> >> microblaze: Move __NR_syscalls from uapi >> >> >> That'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. M
