[PATCH 00/11] support SCTLR2_ELx

Yeoreum Yun yeoreum.yun at arm.com
Mon Aug 4 05:17:13 PDT 2025


This series introduces initial support for the SCTLR2_ELx registers in Linux.
The feature is optional starting from ARMv8.8/ARMv9.3,
and becomes mandatory from ARMv8.9/ARMv9.4.

Currently, Linux has no strict need to modify SCTLR2_ELx—
at least assuming that firmware initializes
these registers to reasonable defaults.

However, several upcoming architectural features will require configuring
control bits in these registers.
Notable examples include FEAT_PAuth_LR and FEAT_CPA2.

This series is based on v6.16 and probably KVM-safe but
Not tested yet:
  - nVHE boot.

Yeoreum Yun (11):
  arm64/sysreg: add system registers SCTLR2_EL2
  arm64: make SCTLR2_EL1 accessible
  arm64: initialise SCTLR2_ELx register at boot time
  arm64: cpufeature: add FEAT_SCTLR2 feature
  arm64: save/restore SCTLR2_EL1 when cpu_suspend()/resume()
  arm64: init SCTLR2_EL1 at cpu_soft_restart()
  arm64: make the per-task SCTLR2_EL1
  KVM: arm64: initialise SCTLR2_EL1 at __kvm_host_psci_cpu_entry()
  KVM: arm64: support SCTLR2_EL1 for guest
  KVM: arm64: nv: support SCTLR2_ELx on nv
  KVM: arm64: expose FEAT_SCTLR2 feature to guest

 arch/arm64/include/asm/el2_setup.h         | 14 +++++++++++-
 arch/arm64/include/asm/kvm_host.h          |  7 ++++++
 arch/arm64/include/asm/processor.h         |  5 +++++
 arch/arm64/include/asm/suspend.h           |  2 +-
 arch/arm64/include/asm/sysreg.h            | 22 ++++++++++++++++++
 arch/arm64/include/asm/vncr_mapping.h      |  1 +
 arch/arm64/kernel/cpu-reset.S              |  6 +++++
 arch/arm64/kernel/cpufeature.c             |  8 +++++++
 arch/arm64/kernel/head.S                   |  5 ++++-
 arch/arm64/kernel/process.c                |  9 ++++++++
 arch/arm64/kvm/emulate-nested.c            |  2 ++
 arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h | 16 +++++++++++++
 arch/arm64/kvm/hyp/nvhe/psci-relay.c       |  3 +++
 arch/arm64/kvm/hyp/vhe/sysreg-sr.c         |  6 +++++
 arch/arm64/kvm/nested.c                    | 13 +++++++++++
 arch/arm64/kvm/sys_regs.c                  | 25 +++++++++++++++++++--
 arch/arm64/mm/proc.S                       | 26 +++++++++++++++-------
 arch/arm64/tools/cpucaps                   |  1 +
 arch/arm64/tools/sysreg                    | 17 ++++++++++++++
 19 files changed, 175 insertions(+), 13 deletions(-)


base-commit: 038d61fd642278bab63ee8ef722c50d10ab01e8f
--
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}




More information about the linux-arm-kernel mailing list