fatload USB was reported to fail on the Sheevaplug. Debugging showed that
this was caused by an incorrect unaligned write to memory in
path_to_uefi().
UEFI on ARM requires that unaligned memory access is enabled.
* ARMv5 does not support unaligned access at all.
* ARMv6 supports unaligned access when we clear the A flag and set the
U flag.
* On ARMv7 unaligned access is possible when clearing the aligned flag,
which we do in function allow_unaligned() (arch/arm/cpu/armv7/sctlr.S).
For none of the other cpus in arch/arm/cpu/ we have implemented a
similar function.
* ARMv8 allows unaligned access.
Let EFI_LOADER on ARM depend on SYS_CPU=armv7 or SYS_CPU=armv8.
Once we have implemented allow_unaligned() for other ARM CPUs we can add
these to Kconfig.
Reported-by: Gray Remlin <gryrmln@gmail.com>
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
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