sunxi: arm64: boot0.h: move fel_stash_addr variable to the front

To be able to return to the BootROM when booting via the FEL USB
protocol, we need to save the CPU state very early, which we need to do
in the embedded AArch32 code. At the moment the pointer to the buffer for
that state is located *after* the code, which makes the PC relative
code fragile: adding or removing instructions will change the distance
to that pointer variable.
The "new" Allwinner A523 SoC requires more state to be saved (GICv3
system registers), but we must do that *only* on that SoC. Conditional
compilation sounds like the easiest solution, but would mean that the
distance to that pointer would change.

Solve this rather easily by moving the pointer to the *front* of the
code: we load that pointer in the first instructions, so the distance
would always stay the same. Later in the code we won't need PC relative
addressing anymore, so this code can grow or shrink easily, for instance
due to conditional compilation.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
1 file changed