On Wed, 2024-06-26 at 09:53 +0200, Jan Beulich wrote: > On 25.06.2024 23:10, Andrew Cooper wrote: > > On 25/06/2024 3:49 pm, Jan Beulich wrote: > > > On 25.06.2024 15:51, Oleksii Kurochko wrote: > > > > --- a/xen/arch/riscv/include/asm/cmpxchg.h > > > > +++ b/xen/arch/riscv/include/asm/cmpxchg.h > > > > @@ -18,6 +18,20 @@ > > > > : "r" (new) \ > > > > : "memory" ); > > > > > > > > +/* > > > > + * Binutils < 2.37 doesn't understand ANDN. If the toolchain > > > > is too > > > > +ld, form > > > Same question: Why's 2.37 suddenly of interest? > > > > You deleted the commit message which explains why: > > Not really. My whole point is that while the intention of the change > looks > okay, description and comment describe things insufficiently, to say > the > least. > > > > RISC-V does a conditional toolchain test for the Zbb extension > > > (xen/arch/riscv/rules.mk), but unconditionally uses the ANDN > > > instruction in emulate_xchg_1_2(). > > > > Either Zbb needs to be mandatory (both in the toolchain and the > > board > > running Xen), or emulate_xchg_1_2() needs to not use the ANDN > > instruction. > > > > I opted for the latter. > > And I agree with that. Okay, then I'll update that in the next patch version.
~ Oleksii
