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@arm.com Signed-off-by: Christoffer Dall christoffer.dall@linaro.org
FWIW: Acked-by: Marc Zyngier marc.zyngier@arm.com
M.