On Fri, Dec 06, 2019 at 11:46:11PM +1100, Michael Ellerman wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA256 > > Hi Linus, > > Please pull another powerpc update for 5.5. > > As you'll see from the diffstat this is mostly not powerpc code. In order to do > KASAN instrumentation of bitops we needed to juggle some of the generic bitops > headers. > > Because those changes potentially affect several architectures I wasn't > confident putting them directly into my tree, so I've had them sitting in a > topic branch. That branch (topic/kasan-bitops) has been in linux-next for a > month, and I've not had any feedback that it's caused any problems. > > So I think this is good to merge, but it's a standalone pull so if anyone does > object it's not a problem. No objections, but here: https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?h=topic/kasan-bitops&id=81d2c6f81996e01fbcd2b5aeefbb519e21c806e9 you write: "Currently bitops-instrumented.h assumes that the architecture provides atomic, non-atomic and locking bitops (e.g. both set_bit and __set_bit). This is true on x86 and s390, but is not always true: there is a generic bitops/non-atomic.h header that provides generic non-atomic operations, and also a generic bitops/lock.h for locking operations." Is there any actual benefit for PPC to using their own atomic bitops over bitops/lock.h ? I'm thinking that the generic code is fairly optimal for most LL/SC architectures. I've been meaning to audit the various architectures and move them over, but alas, it's something I've not yet had time for...
