Re: [PATCH v14 09/10] arch, mm: wire up memfd_secret system call were relevant

On Thu, 3 Dec 2020 08:29:48 +0200 Mike Rapoport rppt@kernel.org wrote:

From: Mike Rapoport rppt@linux.ibm.com

Wire up memfd_secret system call on architectures that define ARCH_HAS_SET_DIRECT_MAP, namely arm64, risc-v and x86.

...

--- a/include/uapi/asm-generic/unistd.h +++ b/include/uapi/asm-generic/unistd.h @@ -861,9 +861,13 @@ __SYSCALL(__NR_faccessat2, sys_faccessat2) __SYSCALL(__NR_process_madvise, sys_process_madvise) #define __NR_watch_mount 441 __SYSCALL(__NR_watch_mount, sys_watch_mount) +#ifdef __ARCH_WANT_MEMFD_SECRET +#define __NR_memfd_secret 442 +__SYSCALL(__NR_memfd_secret, sys_memfd_secret) +#endif

Why do we add the ifdef? Can't we simply define the syscall on all architectures and let sys_ni do its thing?