Re: [PATCH 12/12] userfaultfd: register uapi generic syscall (aarch64)

[Mathieu Desnoyers <mathieu.desnoyers@efficios.com>]

----- On Sep 15, 2015, at 4:02 PM, Andrew Morton akpm@linux-foundation.org wrote:

> On Tue,  8 Sep 2015 22:43:30 +0200 Andrea Arcangeli <aarcange@redhat.com> wrote:
> 
>> From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
>> 
>> Add the userfaultfd syscalls to uapi asm-generic, it was tested with
>> postcopy live migration on aarch64 with both 4k and 64k pagesize kernels.
>> 
>> ...
>>
>> --- a/include/uapi/asm-generic/unistd.h
>> +++ b/include/uapi/asm-generic/unistd.h
>> @@ -709,9 +709,11 @@ __SYSCALL(__NR_memfd_create, sys_memfd_create)
>>  __SYSCALL(__NR_bpf, sys_bpf)
>>  #define __NR_execveat 281
>>  __SC_COMP(__NR_execveat, sys_execveat, compat_sys_execveat)
>> +#define __NR_userfaultfd 282
>> +__SYSCALL(__NR_userfaultfd, sys_userfaultfd)
>>  
>>  #undef __NR_syscalls
>> -#define __NR_syscalls 282
>> +#define __NR_syscalls 283
> 
> sys_membarrier got there first.  Does this version look OK?

Hi Andrew,

Since userfaultfd also made it into 4.3-rc1, bumping the system
call number of sys_membarrier in asm-generic seems to be a good
approach to handle this conflict. We can probably expect conflicts
on other architectures too when architecture maintainers wire up
membarrier and userfaultfd.

Thanks!

Mathieu

> 
> From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> Subject: userfaultfd: register uapi generic syscall (aarch64)
> 
> Add the userfaultfd syscalls to uapi asm-generic, it was tested with
> postcopy live migration on aarch64 with both 4k and 64k pagesize kernels.
> 
> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
> 
> include/uapi/asm-generic/unistd.h |    8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff -puN
> include/uapi/asm-generic/unistd.h~userfaultfd-register-uapi-generic-syscall-aarch64
> include/uapi/asm-generic/unistd.h
> ---
> a/include/uapi/asm-generic/unistd.h~userfaultfd-register-uapi-generic-syscall-aarch64
> +++ a/include/uapi/asm-generic/unistd.h
> @@ -709,17 +709,19 @@ __SYSCALL(__NR_memfd_create, sys_memfd_c
> __SYSCALL(__NR_bpf, sys_bpf)
> #define __NR_execveat 281
> __SC_COMP(__NR_execveat, sys_execveat, compat_sys_execveat)
> -#define __NR_membarrier 282
> +#define __NR_userfaultfd 282
> +__SYSCALL(__NR_userfaultfd, sys_userfaultfd)
> +#define __NR_membarrier 283
> __SYSCALL(__NR_membarrier, sys_membarrier)
> 
> #undef __NR_syscalls
> -#define __NR_syscalls 283
> +#define __NR_syscalls 284
> 
> /*
>  * All syscalls below here should go away really,
>  * these are provided for both review and as a porting
>  * help for the C library version.
> -*
> + *
>  * Last chance: are any of these important enough to
>  * enable by default?
>  */
> _

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com

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