Re: [PATCH 0/2] Support compiling out the prctl syscall

[Josh Triplett]

On Wed, Nov 09, 2016 at 01:26:53AM +0100, Arnd Bergmann wrote:
> On Tuesday, November 8, 2016 4:17:47 PM CET Josh Triplett wrote:
> > Some embedded systems can do without the prctl syscall, saving some space.
> > 
> > This also avoids regular increases in tinyconfig size as people add more
> > non-optional functionality to prctl (observed via the 0-day kernel
> > infrastructure).
> > 
> > The first patch moves prctl and all its helpers into a separate source file,
> > kernel/prctl.c, to allow making it optional via the Makefile without any
> > ifdefs.  The second patch adds the Kconfig option to make prctl optional.
> > 
> > Josh Triplett (2):
> >   kernel: Move prctl and helpers from kernel/sys.c to new kernel/prctl.c
> >   kernel: Support compiling out the prctl syscall
> > 
> 
> Both of these look really nice to me. Another syscall that comes to
> mind as a candidate to be made optional is ptrace, and I've added
> Nicolas Pitre to Cc here, as he has looked into this before.

I've looked at that as well; it's a rather more complex patch, as
several other bits of the kernel hook into ptrace or otherwise depend on
ptrace.  (And ptrace_may_access will need to stick around even when
ptrace doesn't.)

- Josh Triplett