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authorMarc Zyngier <marc.zyngier@arm.com>2015-09-30 14:05:17 +0300
committerMarc Zyngier <marc.zyngier@arm.com>2015-10-10 00:16:57 +0300
commit6d32ab2d8a982ffd46c4dcad9739292f57bc26de (patch)
tree9acf0cba051715af0af4c43c32f279ded3b8d4ea /Documentation/arm64/booting.txt
parent76e52dd01cabc340c1a58f540c9d6bf0e79c6b23 (diff)
downloadlinux-6d32ab2d8a982ffd46c4dcad9739292f57bc26de.tar.xz
arm64: Update booting requirements for GICv3 in GICv2 mode
The current requirements do not describe the case where a GICv3 system gets booted with system register access disabled, and expect the kernel to drive GICv3 in GICv2 mode. Describe the expected settings for that particular case. Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'Documentation/arm64/booting.txt')
-rw-r--r--Documentation/arm64/booting.txt11
1 files changed, 10 insertions, 1 deletions
diff --git a/Documentation/arm64/booting.txt b/Documentation/arm64/booting.txt
index 7d9d3c2286b2..369a4f48eb0d 100644
--- a/Documentation/arm64/booting.txt
+++ b/Documentation/arm64/booting.txt
@@ -173,13 +173,22 @@ Before jumping into the kernel, the following conditions must be met:
the kernel image will be entered must be initialised by software at a
higher exception level to prevent execution in an UNKNOWN state.
- For systems with a GICv3 interrupt controller:
+ For systems with a GICv3 interrupt controller to be used in v3 mode:
- If EL3 is present:
ICC_SRE_EL3.Enable (bit 3) must be initialiased to 0b1.
ICC_SRE_EL3.SRE (bit 0) must be initialised to 0b1.
- If the kernel is entered at EL1:
ICC.SRE_EL2.Enable (bit 3) must be initialised to 0b1
ICC_SRE_EL2.SRE (bit 0) must be initialised to 0b1.
+ - The DT or ACPI tables must describe a GICv3 interrupt controller.
+
+ For systems with a GICv3 interrupt controller to be used in
+ compatibility (v2) mode:
+ - If EL3 is present:
+ ICC_SRE_EL3.SRE (bit 0) must be initialised to 0b0.
+ - If the kernel is entered at EL1:
+ ICC_SRE_EL2.SRE (bit 0) must be initialised to 0b0.
+ - The DT or ACPI tables must describe a GICv2 interrupt controller.
The requirements described above for CPU mode, caches, MMUs, architected
timers, coherency and system registers apply to all CPUs. All CPUs must