Re: [PATCH 07/10] riscv: add ISA extension parsing for Zcmop

[Deepak Gupta <debug@rivosinc.com>]

On Wed, Apr 10, 2024 at 11:27:16PM +0100, Conor Dooley wrote:
>On Wed, Apr 10, 2024 at 11:16:11PM +0100, Conor Dooley wrote:
>> On Wed, Apr 10, 2024 at 02:32:41PM -0700, Deepak Gupta wrote:
>> > On Wed, Apr 10, 2024 at 11:11:00AM +0200, Clément Léger wrote:
>> > > Add parsing for Zcmop ISA extension which was ratified in commit
>> > > b854a709c00 ("Zcmop is ratified/1.0") of the riscv-isa-manual.
>> > >
>> > > Signed-off-by: Clément Léger <cleger@rivosinc.com>
>> > > ---
>> > > arch/riscv/include/asm/hwcap.h | 1 +
>> > > arch/riscv/kernel/cpufeature.c | 1 +
>> > > 2 files changed, 2 insertions(+)
>> > >
>> > > diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
>> > > index b7551bad341b..cff7660de268 100644
>> > > --- a/arch/riscv/include/asm/hwcap.h
>> > > +++ b/arch/riscv/include/asm/hwcap.h
>> > > @@ -86,6 +86,7 @@
>> > > #define RISCV_ISA_EXT_ZCB		77
>> > > #define RISCV_ISA_EXT_ZCD		78
>> > > #define RISCV_ISA_EXT_ZCF		79
>> > > +#define RISCV_ISA_EXT_ZCMOP		80
>> > >
>> > > #define RISCV_ISA_EXT_XLINUXENVCFG	127
>> > >
>> > > diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
>> > > index 09dee071274d..f1450cd7231e 100644
>> > > --- a/arch/riscv/kernel/cpufeature.c
>> > > +++ b/arch/riscv/kernel/cpufeature.c
>> > > @@ -265,6 +265,7 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
>> > > 	__RISCV_ISA_EXT_DATA(zcb, RISCV_ISA_EXT_ZCB),
>> > > 	__RISCV_ISA_EXT_DATA(zcd, RISCV_ISA_EXT_ZCD),
>> > > 	__RISCV_ISA_EXT_DATA(zcf, RISCV_ISA_EXT_ZCF),
>> > > +	__RISCV_ISA_EXT_DATA(zcmop, RISCV_ISA_EXT_ZCMOP),
>> >
>> > As per spec zcmop is dependent on zca. So perhaps below ?
>> >
>> > __RISCV_ISA_EXT_SUPERSET(zicboz, RISCV_ISA_EXT_ZCMOP, RISCV_ISA_EXT_ZCA)
>>
>> What's zicboz got to do with it, copy-pasto I guess?

Yes, copy-pasta :-)

>> If we're gonna imply stuff like this though I think we need some
>> comments explaining why it's okay.
>
>Also, I'm inclined to call that out specifically in the binding, I've
>not yet checked if dependencies actually work for elements of a string
>array like the do for individual properties. I'll todo list that..

Earlier examples of specifying dependency on envcfg actually had functional
use case.
So you are right, I am not sure if its actually needed in this particular case.

And yes definitley, dependency should be mentioned in binding.