[PATCH v2] ARM: KVM: Fix 64-bit coprocessor handling
Marc Zyngier
marc.zyngier at arm.com
Thu Aug 8 04:22:00 EDT 2013
On 06/08/13 19:40, Christoffer Dall wrote:
> The PAR was exported as CRn == 7 and CRm == 0, but in fact the primary
> coprocessor register number was determined by CRm for 64-bit coprocessor
> registers as the user space API was modeled after the coprocessor
> access instructions (see the ARM ARM rev. C - B3-1445).
>
> However, just changing the CRn to CRm breaks the sorting check when
> booting the kernel, because the internal kernel logic always treats CRn
> as the primary register number, and it makes the table sorting
> impossible to understand for humans.
>
> Alternatively we could change the logic to always have CRn == CRm, but
> that becomes unclear in the number of ways we do look up of a coprocessor
> register. We could also have a separate 64-bit table but that feels
> somewhat over-engineered. Instead, keep CRn the primary representation
> of the primary coproc. register number in-kernel and always export the
> primary number as CRm as per the existing user space ABI.
>
> Note: The TTBR registers just magically worked because they happened to
> follow the CRn(0) regs and were considered CRn(0) in the in-kernel
> representation.
>
> Cc: Marc Zyngier <marc.zyngier at arm.com>
> Signed-off-by: Christoffer Dall <christoffer.dall at linaro.org>
FWIW: Acked-by: Marc Zyngier <marc.zyngier at arm.com>
M.
--
Jazz is not dead. It just smells funny...
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