Re: [PATCH 2/2] fs: Wire up sendfd() syscall (all architectures)

From: Geert Uytterhoeven
Date: Tue Dec 02 2014 - 09:38:29 EST


Hi Alex,

On Tue, Dec 2, 2014 at 3:31 PM, Alex Dubov <alex.dubov@xxxxxxxxx> wrote:
> On Tue, Dec 2, 2014 at 10:42 PM, Michal Simek <monstr@xxxxxxxxx> wrote:
>> On 12/02/2014 09:01 AM, Geert Uytterhoeven wrote:
>>> This really needs a CC to linux-arch (added).
>>>
>>> On Tue, Dec 2, 2014 at 5:35 AM, Alex Dubov <alex.dubov@xxxxxxxxx> wrote:
>>>> Signed-off-by: Alex Dubov <oakad@xxxxxxxxx>
>>>> ---
>
>> The same for microblaze here
>> arch/microblaze/include/asm/unistd.h
>
> This invites the question as to why the __NR_syscalls macro is not
> defined in uapi/asm/unistd.h on those architectures, where it will be
> easier to spot? After all, asm/unistd.h includes uapi/asm/unistd.h
> unconditionally.

Because it's not part of the ABI?

There may be multiple ABIs, with multiple syscall ranges.
Userspace only needs to know if a syscall is available, not what the
valid syscall number range is.
The kernel does need to know the size of the full syscall table.

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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