Re: [Xenomai] Mayday mechanism broken on x86-64 - simpler approach feasible?

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2015-02-12 17:36, Jan Kiszka wrote:
>> As I mentioned earlier, I'd rather fix the MAYDAY implementation for
>> x86_64 instead of forking the implementation between MMU-enabled and
>> MMU-less architectures, also affecting powerpc, arm and x86_32 in the
>> same move. Fortunately, the current implementation allows very specific
>> tweaks to be applied on a per-architecture basis. This one fixes the
>> issue for Cobalt on x86_64, and could be easily backported to 2.6.x:
>>
>> http://git.xenomai.org/xenomai-3.git/commit/?h=next&id=6db20901963d634b9786467c711c2ba526db48a2
> 
> Looks almost good - except for the detail that some bits of the
> instruction pointer are lost on return from the syscall (int vs. long
> return type). Patches in the making.

Will take longer - I need to convert all cobalt syscalls.

We have a sleeping bug there, though likely not seen in practice, with
syscalls returning values > INT_MAX (size_t...). The problem is that
handle_head/root_syscall only forwarded 32-bits so far.

Jan

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