lkml.org 
[lkml]   [2015]   [May]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: powerpc: Enabling sys_kcmp for CRIU
Date
On Tue, 2015-05-05 at 15:30:21 UTC, Laurent Dufour wrote:
> The commit 8170a83f15ee ("powerpc: Wireup the kcmp syscall to sys_ni") has
> disabled the kcmp syscall for powerpc. This has been done due to the use
> of unsigned long parameters which may require a dedicated wrapper to handle
> 32bit process on top of 64bit kernel. However in the kcmp() case, the 2
> unsigned long parameters are currently only used to carry file descriptors
> from user space to the kernel. Since such a parameter is passed through
> register, and file descriptor doesn't need to get extended, there is,
> today, no need for a wrapper.
>
> In the case there will be a need to pass address in or out of this system
> call, then a wrapper could be required, it will then be to care of it.
>
> As today this is not the case, it is safe to enable kcmp() on powerpc.

That's mostly convincing. Though I see that s390 does have a compat wrapper,
i386 doesn't. So who knows what that means.

But, there's a selftest in tools/testing/selftests/kcmp. So can you run that as
32-bit and confirm it works? Then I'd be 100% convinced :)

cheers


\
 
 \ /
  Last update: 2015-05-11 12:41    [W:0.039 / U:4.108 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site