[PATCH v10 1/3] arm64: Add __NR_* definitions for compat syscalls

Arnd Bergmann arnd at arndb.de
Fri Jul 4 04:17:43 PDT 2014

On Friday 04 July 2014 20:05:47 AKASHI Takahiro wrote:
> On 07/04/2014 07:06 PM, Arnd Bergmann wrote:
> > On Friday 04 July 2014 16:28:29 AKASHI Takahiro wrote:
> >> From: Catalin Marinas <catalin.marinas at arm.com>
> >>
> >> This patch adds __NR_* definitions to asm/unistd32.h, moves the
> >> __NR_compat_* definitions to asm/unistd.h and removes all the explicit
> >> unistd32.h includes apart from the one building the compat syscall
> >> table. The aim is to have the compat __NR_* definitions available but
> >> without colliding with the native syscall definitions.
> >>
> >> And adds more syscall definitions for 3.16.
> >
> > Can you explain in more detail why you want to add those macros? I've
> > looked at all three patches in the series but can't find any code using
> > them.
> Right. "unistd32.h" is not used by this patch, but by lib/compat_audit.c.
> when I thought of adding audit support for arm64, there was duplicated code
> of auditing compat system calls across many architectures.
> lib/compat_audit.c fixes this issue but at the same time it also requires
> __NR_* macros for a couple of compat system calls which arm64 didn't have.
> In the first implementation, I generated an extra generated/asm/unistd_32.h
> from the original asm/unist32.h by using a sed script. But Catalin suggested
> (agreed?) to modify unistd32.h for this purpose.
> See
> http://lists.infradead.org/pipermail/linux-arm-kernel/2014-January/228992.html

Ok, thanks for the explanation. It would be good to have that in the changeset
comment as well, in case other people wonder about the same question.


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