[PATCH 04/10] arm64: mops: document boot requirements for MOPS
From: Kristina Martsenko <hidden>
Date: 2023-02-16 16:01:57
Also in:
kvmarm, lkml
Subsystem:
documentation, the rest · Maintainers:
Jonathan Corbet, Linus Torvalds
FEAT_MOPS introduces new instructions, we require that these instructions not execute as UNDEFINED when we identify that the feature is supported. Additionally, the instructions may generate a Memory Copy or Memory Set exception, we require that the exception be taken to EL1 in case EL2 is not able to correctly handle it. Signed-off-by: Kristina Martsenko <redacted> --- Documentation/arm64/booting.rst | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/Documentation/arm64/booting.rst b/Documentation/arm64/booting.rst
index ffeccdd6bdac..f3913ee94c42 100644
--- a/Documentation/arm64/booting.rst
+++ b/Documentation/arm64/booting.rst@@ -379,6 +379,14 @@ Before jumping into the kernel, the following conditions must be met: - SMCR_EL2.EZT0 (bit 30) must be initialised to 0b1. + For CPUs with Memory Copy and Memory Set instructions (FEAT_MOPS): + + - If the kernel is entered at EL1 and EL2 is present: + + - HCRX_EL2.MSCEn (bit 11) must be initialised to 0b1. + + - HCRX_EL2.MCE2 (bit 10) must be initialised to 0b0. + 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. Where the values documented
--
2.25.1
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