Re: patches for test-and-set without ll/sc (Re: thread-ready ABIs)

[Andreas Jaeger <aj at suse dot de>]

Ulrich Drepper <drepper@redhat.com> writes:

> Machida Hiroyuki <machida@sm.sony.co.jp> writes:
>
>>   * glibc change:
>> 
>> 	We implement  test_and_set(addr, val) as follows,
>> 
>> 		Do mmap /dev/tst to _TST_START_MAGIC, if not yet mapped.
>> 		call _TST_START_MAGIC(addr, val)
>> 	
>> 	If we can't open /dev/tst then, use sysmips() as final resort.
>
> First, the patch as it is unacceptable.  A file with copyright Sony?
> All the code must be copyrighted by the FSF.  Sony will have to assign
> the copyright for the code to the FSF.
>
> Also, no such change can be accepted until the necessary kernel
> changes are in the official kernel sources.  I cannot make any
> exceptions since otherwise all kinds of people want to see support for
> their local hack added.
>
> Furthermore, the symbols were not available in version 2.2.  Therefore
> they cannot be exported with this version.  It'll either be 2.2.6 (if
> their ever will be such a release) or 2.3.
>
> And finally, the patch should be sent to the glibc MIPS maintainer for
> review.  The question is who feels responsible...

I'll look into it later in more detail.

But for now, let me just tell that I agree with Ulrich's comments.
Additionally I'd like to wait with adding this patch until:
- a solution for the thread register is found for MIPS (and those
  solution should not conflict with this patch)
- the kernel side patches have been adopted.

Therefore please discuss this with the kernel and ABI folks, and then
let's look again at the issues.

Andreas
-- 
 Andreas Jaeger
  SuSE Labs aj@suse.de
   private aj@arthur.inka.de
    http://www.suse.de/~aj