Re: [PATCH v3 02/10] arm/domain: Get rid of READ/WRITE_SYSREG32

[Julien Grall <julien@xxxxxxx>]

Hi Michal,

On 05/05/2021 08:43, Michal Orzel wrote:
> AArch64 registers are 64bit whereas AArch32 registers
> are 32bit or 64bit. MSR/MRS are expecting 64bit values thus
> we should get rid of helpers READ/WRITE_SYSREG32
> in favour of using READ/WRITE_SYSREG.
> We should also use register_t type when reading sysregs
> which can correspond to uint64_t or uint32_t.
> Even though many AArch64 registers have upper 32bit reserved
> it does not mean that they can't be widen in the future.
>
> Modify type of register cntkctl to register_t.
>
> Modify accesses to thumbee registers to use READ/WRITE_SYSREG.
> Thumbee registers are only usable by a 32bit domain and in fact
> should be only accessed on ARMv7 as they were retrospectively dropped
> on ARMv8.
Sorry for not replying on v2. How about:

"
Thumbee registers are only usable by a 32-bit domain and therefore we 
can just store the bottom 32-bit (IOW there is no type change). In fact, 
this could technically be restricted to Armv7 HW (the support was 
dropped retrospectively in Armv8) but leave it as-is for now.
"

If you are happy with it, I will do it on commit.

Cheers,

--
Julien Grall