lkml.org 
[lkml]   [2013]   [Jan]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC PATCH v1 14/31] ARC: syscall support
On Thursday 15 November 2012 06:05 PM, Arnd Bergmann wrote:
> On Thursday 15 November 2012, Vineet Gupta wrote:
>> So the primary concern here is not breaking the userspace ABI - right ?
>>
>> For syscalls I agree that we will indeed need to fix the ABI - by fixing
>> uClibc. And if uClibc doesn't merge the fixes we can stay out of tree
>> for uClibc - as we currently already are.
>
> I'm sure we can find a solution for uClibc. We already have seven
> architectures using the generic syscalls, including at least one
> (arm64) that is going to run on a large number of installations
> in the future.
>
>> For gdbserver, the kernel provides the complete regset ABI. However it
>> also provides a very limited version of old ABI - i.e. ptrace with
>> PEEKUSR/POKEUSR. Note that latter is just a shim layer and it reuses the
>> regset callbacks. This allows us to support the legacy gdbserver. If and
>> when gdbserver upgrades it can switch over to new interface. So all
>> along there will be NO ABI breakage at all. The cost is couple extra
>> functions in kernel which we might have to maintain for some foreseeable
>> future. Agree ?
>
> It's more a question of principle. The rule is that we don't break user
> space, and ptrace is just another user space interface is this. If
> we merge it now, we will keep it around forever, taking it out later
> is not an option IMHO. My preference would be not to merge the backwards
> compatibility layer for ptrace at all, but I'm willing to listen to
> other people that support your view if you want to keep it. In one
> way, ptrace is less critical than the other system calls, and that is
> because it's already architecture specific.
>
> Arnd
>

OK as of now the legacy syscall ABI and ptrace PEEKUSR/POKEUSR are taken out of
submissions tree - we'll carry these out-of-tree for sometime before eventually
moving to newer uClibc/gdbserver which don't need these O-O-T patches.

-Vineet


\
 
 \ /
  Last update: 2013-01-17 07:01    [W:0.108 / U:0.064 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site