[PATCH v2 0/4] arm64: Booting clarifications and fine grained traps setup
Mark Brown
broonie at kernel.org
Thu Apr 1 19:09:38 BST 2021
Currently there are a number of areas where we are not explicit about
how system registers should be configured when booting the kernel,
provide more detailed guidance to help ensure people get things right.
I'm not entirely happy with the wording on use of specified reset values
so it is a separate patch at the end, I worry that the requirement is
too strict.
This was triggered by noticing that it was in spec to leave fine grained
traps to EL2 enabled so explicitly disable them at boot, this is sent as
part of the same series since doing so means we require that EL3 provide
access to fine grained traps in the same document.
v2:
- Pull booting and FGT setup into a single series.
- Require system registers at or below the level the kernel is entered
to be initialised, not just those at that level.
- Rather than documenting the desired EL2 setup for FGT add a general
statement about how we expect registers to be set up.
- Reorder register initialisation in el2_setup.h.
- Document requirement for SCR_EL3.FGTEn to be 1.
Mark Brown (4):
arm64: Document requirements for fine grained traps at boot
arm64: Disable fine grained traps on boot
arm64: Require that system registers at all visible ELs be initialized
arm64: Document values for system registers on boot
Documentation/arm64/booting.rst | 15 ++++++++++++---
arch/arm64/include/asm/el2_setup.h | 21 +++++++++++++++++++++
arch/arm64/include/asm/sysreg.h | 6 ++++++
3 files changed, 39 insertions(+), 3 deletions(-)
base-commit: 1e28eed17697bcf343c6743f0028cc3b5dd88bf0
--
2.20.1
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