From f32c053b9806e42209d40e9ce7ed6f7f8be3be3b Mon Sep 17 00:00:00 2001 From: Kristina Martsenko Date: Tue, 9 May 2023 15:22:28 +0100 Subject: [PATCH] arm64: mops: document boot requirements for MOPS FEAT_MOPS introduces new instructions, we require that these instructions not execute as UNDEFINED when we identify that the feature is supported. Signed-off-by: Kristina Martsenko Link: https://lore.kernel.org/r/20230509142235.3284028-5-kristina.martsenko@arm.com Signed-off-by: Catalin Marinas --- Documentation/arm64/booting.rst | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/Documentation/arm64/booting.rst b/Documentation/arm64/booting.rst index ffeccdd6bdac9..b3bbf330ed0ab 100644 --- a/Documentation/arm64/booting.rst +++ b/Documentation/arm64/booting.rst @@ -379,6 +379,12 @@ 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. + 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 -- 2.30.2