Commit ee61f36d authored Apr 12, 2021 by Mark Brown Committed by Catalin Marinas Apr 30, 2021

arm64: Relax booting requirements for configuration of traps



Currently we require that a number of system registers be configured to
disable traps when starting the kernel. Add an explicit note that the
requirement is that the system behave as if the traps are disabled so
transparent handling of the traps is fine, this should be implicit for
people familiar with working with standards documents but it doesn't hurt
to be explicit.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210412151955.16078-2-broonie@kernel.org


Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

parent f6334b17

Documentation/arm64/booting.rst

+4 −1

Original line number	Diff line number	Diff line
		@@ -279,7 +279,10 @@ Before jumping into the kernel, the following conditions must be met:

		The requirements described above for CPU mode, caches, MMUs, architected
		timers, coherency and system registers apply to all CPUs. All CPUs must
		enter the kernel in the same exception level.
		enter the kernel in the same exception level. Where the values documented
		disable traps it is permissible for these traps to be enabled so long as
		those traps are handled transparently by higher exception levels as though
		the values documented were set.

		The boot loader is expected to enter the kernel on each CPU in the
		following manner: