gem5: Add support for gem5's extended GIC mode

gem5's GIC model contains a gem5-specific extension that enables
support for up to 255 CPUs. When enabled, the GIC interprets registers
where a CPU bitmask would normally be present as a CPU ID.

This extensions need to be enabled by setting the OF compatible string
to "gem5,gic".

Kudos to Matt Evans for the original version of this patch.

Change-Id: I1a8776f1adcbfcd97813573050a8595176de6a7e
Signed-off-by: Andreas Sandberg <>
Reviewed-by: Stephan Diestelhorst <>
Reviewed-by: Curtis Dunham <>
[Ported to 4.4]
Signed-off-by: Andreas Sandberg <>
[ Ported to 4.9 and merged initialization fixup from 4.4.]
Signed-off-by: Andreas Sandberg <>
1 file changed