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Date:   Sun, 6 Dec 2020 13:30:48 +0200
From:   Mike Rapoport <rppt@linux.ibm.com>
To:     Andrew Morton <akpm@linux-foundation.org>
Cc:     Mike Rapoport <rppt@kernel.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Andy Lutomirski <luto@kernel.org>,
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        Dave Hansen <dave.hansen@linux.intel.com>,
        David Hildenbrand <david@redhat.com>,
        Elena Reshetova <elena.reshetova@intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
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Subject: Re: [PATCH v14 09/10] arch, mm: wire up memfd_secret system call
 were relevant
Message-ID: <20201206113048.GC123287@linux.ibm.com>
References: <20201203062949.5484-1-rppt@kernel.org>
 <20201203062949.5484-10-rppt@kernel.org>
 <20201203153916.91f0f80dcb8a0fa81fc341fa@linux-foundation.org>
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On Thu, Dec 03, 2020 at 03:39:16PM -0800, Andrew Morton wrote:
> 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?
 
I quite blindly copied it from clone3. I agree there is no real need for
it and sys_ni handles this just fine.

-- 
Sincerely yours,
Mike.