Hi,
On 17/10/2023 15:07, Michal Orzel wrote:
On 17/10/2023 14:52, Julien Grall wrote:
The macro load_paddr() requires to know the offset between the
physical location of Xen and the virtual location.
When using the MPU, x20 will always be 0. Rather than wasting
a register for a compile-time constant value, it would be best if
we can avoid using load_paddr() altogher in the common head.S code.
s/altogher/altogether/
I will fix it.
The current use of load_paddr() are equivalent to adr_l() because
the MMU is off.
All the use of load_paddr() in arm64/head.S are now replaced with
adr_l(). With that, load_paddr() can now be moved in arm64/mmu/head.S.
For now, x20 is still unconditionally set. But this could change
in the future if needed.
Signed-off-by: Julien Grall <[email protected]>
Reviewed-by: Michal Orzel <[email protected]>
Side note:
Looking at all the uses of load_paddr(), none of them takes place after
enabling MMU
which would indicate that we actually don't need this macro at all. Do you
agree?
I agree they are none today called after enabling the MMU. But,
create_table_entry() used to be called after and I can't rule out this
will not happen again.
So I don't think we should replace the use in create_table_entry() with
adr_l. We could consider to open-code code though.
Cheers,
--
Julien Grall
