From be0ddf5293a7895a8c9096e1a8560930c6a0ab3f Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Tue, 1 Nov 2022 11:27:14 +0000 Subject: [PATCH] arm64: booting: Document our requirements for fine grained traps with SME With SME we require that fine grained traps on access to TPIDR2_EL0 and SMPRI_EL1 are disabled but did not document that fact. Add the relevant register bits. Signed-off-by: Mark Brown Reviewed-by: Oliver Upton Acked-by: Catalin Marinas Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20221101112716.52035-2-broonie@kernel.org --- Documentation/arm64/booting.rst | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/Documentation/arm64/booting.rst b/Documentation/arm64/booting.rst index 8aefa1001ae5..8c324ad638de 100644 --- a/Documentation/arm64/booting.rst +++ b/Documentation/arm64/booting.rst @@ -340,6 +340,14 @@ Before jumping into the kernel, the following conditions must be met: - SMCR_EL2.LEN must be initialised to the same value for all CPUs the kernel will execute on. + - HWFGRTR_EL2.nTPIDR2_EL0 (bit 55) must be initialised to 0b01. + + - HWFGWTR_EL2.nTPIDR2_EL0 (bit 55) must be initialised to 0b01. + + - HWFGRTR_EL2.nSMPRI_EL1 (bit 54) must be initialised to 0b01. + + - HWFGWTR_EL2.nSMPRI_EL1 (bit 54) must be initialised to 0b01. + For CPUs with the Scalable Matrix Extension FA64 feature (FEAT_SME_FA64) - If EL3 is present: -- 2.20.1