Some bits in CPTR are defined as RES1 in the architecture.  Setting
these bits to zero may unintentionally enable future architecture
extensions, allowing guests to use them without supervision by the host.

This would be bad: for forwards compatibility, this patch makes
sure the affected bits are always written with 1, not 0.

This patch only addresses CPTR_EL2.  Initialisation of other system
registers may still need review.
Reviewed-by: NMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

As we've now switched to the new world switch implementation,
remove the weak attributes, as nobody is supposed to override
it anymore.
Acked-by: NChristoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

So far, we've implemented the new world switch with a completely
different namespace, so that we could have both implementation
compiled in.

Let's take things one step further by adding weak aliases that
have the same names as the original implementation. The weak
attributes allows the new implementation to be overriden by the
old one, and everything still work.

At a later point, we'll be able to simply drop the old code, and
everything will hopefully keep working, thanks to the aliases we
have just added. This also saves us repainting all the callers.
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
Acked-by: NChristoffer Dall <christoffer.dall@linaro.org>

Add the panic handler, together with the small bits of assembly
code to call the kernel's panic implementation.
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
Reviewed-by: NChristoffer Dall <christoffer.dall@linaro.org>

Implement the fpsimd save restore, keeping the lazy part in
assembler (as returning to C would be overkill).
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
Reviewed-by: NChristoffer Dall <christoffer.dall@linaro.org>

Implement the core of the world switch in C. Not everything is there
yet, and there is nothing to re-enter the world switch either.

But this already outlines the code structure well enough.
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
Reviewed-by: NChristoffer Dall <christoffer.dall@linaro.org>