From 6d32ab2d8a982ffd46c4dcad9739292f57bc26de Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Wed, 30 Sep 2015 12:05:17 +0100 Subject: 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 Signed-off-by: Marc Zyngier --- Documentation/arm64/booting.txt | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) 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 -- cgit v1.2.3