svn commit: r221550 - head/sys/powerpc/conf

[Attilio Rao]

2011/5/6 Attilio Rao <attilio at freebsd.org>:
> 2011/5/6 Nathan Whitehorn <nwhitehorn at freebsd.org>:
>> Author: nwhitehorn
>> Date: Fri May  6 20:43:02 2011
>> New Revision: 221550
>> URL: http://svn.freebsd.org/changeset/base/221550
>>
>> Log:
>>  SMP has worked perfectly for a very long time on 32-bit PowerPC on both
>>  UP and SMP hardware. Enable it in GENERIC.
>>
>
> While working on largeSMP, I think there is a breakage in atomic.h.
> More specifically, atomic_store_rel_long() (and related functions) are
> not going to properly work because powerpc defines them as:
>
> atomic_store_rel_long -> atomic_store_rel_32(volatile u_int *p, u_int v)
>
> while this should really follow the long arguments.
>
> This happens because powerpc doesn't follow the other architectures
> semantic on defining the "similar" atomic operations.
> Other arches define an hardcode version of _type version of the
> function and than make a macro the _32 (or whatever) version.
> In other words this is what they do:
>
> void
> atomic_store_rel_32()
> {
> ...
> }
>
> #define atomic_store_rel_int atomic_store_rel_32
>
> which si clearly dangerous for cases as reported above. Maybe that
> could be fixed by passing sized types, rather than simply int or long
> in numbered version, but I'd really prefer to follow the semantic by
> other architectures and then have:
>
> void
> atomic_store_rel_int()
> {
> ...
> }
>
> #define atomic_store_rel_32 atomic_store_rel_int
>
> I fixed the ATOMIC_STORE_LOAD case in my code, because I needed it,
> but the final cleanup is much bigger.
> I can make a patch tomorrow if you can test it.
>

Can you please test and review this patch?:
http://www.freebsd.org/~attilio/largeSMP/atomic-powerpc.diff

Unfortunately I'm having issues with the toolchains in atm, so I can't
really neither test compile it.

Let me know,
Attilio


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