On Sun, 2012-04-22 at 18:16 -0700, Brendan Conoboy wrote: > As we get closer to having 100% package coverage in F17-ARM we're > running into harder build failures due to the limitations of the chips > we're building for. The problem I've noticed on many of the recent > failures is due to the lack of atomic operations (These didn't arrive > until ARMv6). What are some examples of these? > How do we want to handle this? I see a few options: > > 1. Abandon armv5 and move to armv6 where some of the operations we need > are available. This will still support the raspberry pi- what about > kirkwood *plugs? That would kill the older plugs -- anything below a d2plug. However: do we care? Much? Going to v6 would let us optimize better for the Raspi, which will have greater market penetration than the plugs when existing orders are filled. Otoh, it's a whole 'nuther rebuild. > 2. Excludearch armv5tel from the affected packages since they'll never > work atomically. > > 3. Accept that these packages simply won't be available to 32 bit Fedora > systems (this is the result of inaction). > > 4. Pretend operations are atomic when they are not. > > 5. Create magic patch that implements atomic operations through software. 6. There is the kernel's "user space atomic helper" (kuser_cmpxchg64) at 0xffff0f60, see Documentation/arm/kernel_user_helpers.txt. The kernel puts an instruction sequence here tuned for the current arch that can be called by userland to provide an atomic compare/exchange -- if it can be done natively, the instruction sequence does that, otherwise it does a syscall (with IRQ protection etc). Would this solve the problems you've identified? -Chris _______________________________________________ arm mailing list arm@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/arm
