On Wed, Mar 19, 2025 at 7:56 PM Alexei Starovoitov <alexei.starovoitov@xxxxxxxxx> wrote: > > On Wed, Mar 19, 2025 at 9:06 AM Uros Bizjak <ubizjak@xxxxxxxxx> wrote: > > > > On Wed, Mar 19, 2025 at 3:55 PM Alexei Starovoitov > > <alexei.starovoitov@xxxxxxxxx> wrote: > > > > > > On Wed, Mar 19, 2025 at 7:36 AM Kumar Kartikeya Dwivedi > > > <memxor@xxxxxxxxx> wrote: > > > > > > > > > > > > > > > > I've sent a fix [0], but unfortunately I was unable to reproduce the > > > > > > problem with an LLVM >= 19 build, idk why. I will try with GCC >= 14 > > > > > > as the patches require to confirm, but based on the error I am 99% > > > > > > sure it will fix the problem. > > > > > > > > > > Probably because __seg_gs has CC_HAS_NAMED_AS depends on CC_IS_GCC. > > > > > Let me give it a go with GCC. > > > > > > > > > > > > > Can confirm now that this fixes it, I just did a build with GCC 14 > > > > where Uros's __percpu checks kick in. > > > > > > Great. Thanks for checking and quick fix. > > > > > > btw clang supports it with __attribute__((address_space(256))), > > > so CC_IS_GCC probably should be relaxed. > > > > https://github.com/llvm/llvm-project/issues/93449 > > > > needs to be fixed first. Also, the feature has to be thoroughly tested > > (preferably by someone having a deep knowledge of clang) before it is > > enabled by default. > > clang error makes sense to me. It is not an error, but an internal compiler error. This should never happen. > What does it even mean to do addr space cast from percpu to normal address: > > __typeof__(int __seg_gs) const_pcpu_hot; > void *__attribute____UNIQUE_ID___addressable_const_pcpu_hot612 = > (void *)(long)&const_pcpu_hot; Please see [1] for an explanation. [1] https://gcc.gnu.org/onlinedocs/gcc/Named-Address-Spaces.html#x86-Named-Address-Spaces Uros.
