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

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.


Julien Grall



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