On 22/04/2021 12:47, Michal Orzel wrote:
Hi Julien,
Hi Michal,
On 20.04.2021 15:37, Julien Grall wrote:
Hi Michal,
On 20/04/2021 08:08, Michal Orzel wrote:
AArch64 system registers are 64bit whereas AArch32 ones
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 sysregs have upper 32bit reserved
it does not mean that they can't be widen in the future.
Modify SCTLR_EL2 accesses to use READ/WRITE_SYSREG.
SCTLR_EL2 already has bits defined in the range [32:63]. So this change is
going to have a side effect as AFAICT head.S will not touch those bits. So they
are now going to be preserved.
The Arm Arm defines them as unknown if implemented. Therefore shouldn't we zero
them somewhere else?
SCTLR_EL2 is set in head.S using SCTLR_EL2_SET which means that we are zeroing
the upper 32bit half.
Ah! I couldn't find the place doing it. Thanks!
I think it is important to point in the commit message this is just a
latent bug because the top 32-bit was not used by Xen. Can you update
the commit message?
Cheers,
--
Julien Grall
