Commit Graph

13 Commits

Author SHA1 Message Date
Mark Brown ca940790d2 arm64: Document requirement for access to FEAT_HCX
v8.7 of the architecture introduced FEAT_HCX which adds an additional
hypervisor configuration register HCRX_EL2. Even though Linux does not
currently make use of this feature let's document that the EL3 trap for
access to the register should be disabled so that we are able to make
use of it in future.

Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210512162350.20349-1-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
2021-05-25 19:05:28 +01:00
Mark Brown ff1c42cdfb arm64: Explicitly document boot requirements for SVE
We do not currently document the requirements for configuration of the
SVE system registers when booting the kernel, let's do so for completeness.

We don't have a hard requirement that the vector lengths configured on
different CPUs on initial boot be consistent since we have logic to
constrain to the minimum supported value but we will reject any late CPUs
which can't support the current maximum and introducing the concept of
late CPUs seemed more complex than was useful so we require that all CPUs
use the same value.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210412151955.16078-4-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-04-30 18:53:43 +01:00
Mark Brown b30dbf4d93 arm64: Explicitly require that FPSIMD instructions do not trap
We do not explicitly require that systems with FPSIMD support and EL3 have
disabled EL3 traps when the kernel is started, while it is unlikely that
systems will get this wrong for the sake of completeness let's spell it
out.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210412151955.16078-3-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-04-30 18:53:43 +01:00
Mark Brown ee61f36d3e arm64: Relax booting requirements for configuration of traps
Currently we require that a number of system registers be configured to
disable traps when starting the kernel. Add an explicit note that the
requirement is that the system behave as if the traps are disabled so
transparent handling of the traps is fine, this should be implicit for
people familiar with working with standards documents but it doesn't hurt
to be explicit.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210412151955.16078-2-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-04-30 18:53:42 +01:00
Mark Brown 230800cd31 arm64: Require that system registers at all visible ELs be initialized
Currently we require that software at a higher exception level initialise
all registers at the exception level the kernel will be entered prior to
starting the kernel in order to ensure that there is nothing uninitialised
which could result in an UNKNOWN state while running the kernel. The
expectation is that the software running at the highest exception levels
will be tightly coupled to the system and can ensure that all available
features are appropriately initialised and that the kernel can initialise
anything else.

There is a gap here in the case where new registers are added to lower
exception levels that require initialisation but the kernel does not yet
understand them. Extend the requirement to also include exception levels
below the one where the kernel is entered to cover this.

Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210401180942.35815-4-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-04-08 18:39:18 +01:00
Mark Brown 3e237387bb arm64: Document requirements for fine grained traps at boot
The arm64 FEAT_FGT extension introduces a set of traps to EL2 for accesses
to small sets of registers and instructions from EL1 and EL0, access to
which is controlled by EL3.  Require access to it so that it is
available to us in future and so that we can ensure these traps are
disabled during boot.

Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210401180942.35815-2-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-04-08 18:39:17 +01:00
Linus Torvalds b23c4771ff A fair amount of stuff this time around, dominated by yet another massive
set from Mauro toward the completion of the RST conversion.  I *really*
 hope we are getting close to the end of this.  Meanwhile, those patches
 reach pretty far afield to update document references around the tree;
 there should be no actual code changes there.  There will be, alas, more of
 the usual trivial merge conflicts.
 
 Beyond that we have more translations, improvements to the sphinx
 scripting, a number of additions to the sysctl documentation, and lots of
 fixes.
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Merge tag 'docs-5.8' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "A fair amount of stuff this time around, dominated by yet another
  massive set from Mauro toward the completion of the RST conversion. I
  *really* hope we are getting close to the end of this. Meanwhile,
  those patches reach pretty far afield to update document references
  around the tree; there should be no actual code changes there. There
  will be, alas, more of the usual trivial merge conflicts.

  Beyond that we have more translations, improvements to the sphinx
  scripting, a number of additions to the sysctl documentation, and lots
  of fixes"

* tag 'docs-5.8' of git://git.lwn.net/linux: (130 commits)
  Documentation: fixes to the maintainer-entry-profile template
  zswap: docs/vm: Fix typo accept_threshold_percent in zswap.rst
  tracing: Fix events.rst section numbering
  docs: acpi: fix old http link and improve document format
  docs: filesystems: add info about efivars content
  Documentation: LSM: Correct the basic LSM description
  mailmap: change email for Ricardo Ribalda
  docs: sysctl/kernel: document unaligned controls
  Documentation: admin-guide: update bug-hunting.rst
  docs: sysctl/kernel: document ngroups_max
  nvdimm: fixes to maintainter-entry-profile
  Documentation/features: Correct RISC-V kprobes support entry
  Documentation/features: Refresh the arch support status files
  Revert "docs: sysctl/kernel: document ngroups_max"
  docs: move locking-specific documents to locking/
  docs: move digsig docs to the security book
  docs: move the kref doc into the core-api book
  docs: add IRQ documentation at the core-api book
  docs: debugging-via-ohci1394.txt: add it to the core-api book
  docs: fix references for ipmi.rst file
  ...
2020-06-01 15:45:27 -07:00
Will Deacon e24e03aa00 arm64: docs: Mandate that the I-cache doesn't hold stale kernel text
Although we require that the loaded kernel Image has been cleaned to the
PoC, we neglect to spell out the state of the I-cache. Although this
should be reasonably obvious, it doesn't hurt to be explicit.

Require that the I-cache doesn't hold any stale entries for the kernel
Image at boot.

Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20200423093658.10602-1-will@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
2020-04-28 14:24:10 +01:00
Mauro Carvalho Chehab 877a37d31e docs: arm64: booting.rst: get rid of some warnings
Get rid of those warnings:

    Documentation/arm64/booting.rst:253: WARNING: Unexpected indentation.
    Documentation/arm64/booting.rst:259: WARNING: Block quote ends without a blank line; unexpected unindent.

By adding an extra blank lines where needed.

While here, use list markups on some places, as otherwise Sphinx
will consider the next lines as continuation of the privious ones.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/121b267be0a102fde73498c31792e5a9309013cc.1586881715.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-20 15:45:23 -06:00
Ionela Voinescu 6abde90881 Documentation: arm64: document support for the AMU extension
The activity monitors extension is an optional extension introduced
by the ARMv8.4 CPU architecture.

Add initial documentation for the AMUv1 extension:
 - arm64/amu.txt: AMUv1 documentation
 - arm64/booting.txt: system registers initialisation

Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2020-03-06 16:02:50 +00:00
Marc Zyngier 7e3a57fa6c arm64: Document ICC_CTLR_EL3.PMHE setting requirements
It goes without saying, but better saying it: the kernel expects
ICC_CTLR_EL3.PMHE to have the same value across all CPUs, and
for that setting not to change during the lifetime of the kernel.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2019-10-15 12:26:15 +01:00
Linus Torvalds d06e415643 Devicetree updates for v5.3:
- DT binding schema examples are now validated against the schemas.
   Various examples are fixed due to that.
 
 - Sync dtc with upstream version v1.5.0-30-g702c1b6c0e73
 
 - Initial schemas for networking bindings. This includes ethernet, phy
   and mdio common bindings with several Allwinner and stmmac converted
   to the schema.
 
 - Conversion of more Arm top-level SoC/board bindings to DT schema
 
 - Conversion of PSCI binding to DT schema
 
 - Rework Arm CPU schema to coexist with other CPU schemas
 
 - Add a bunch of missing vendor prefixes and new ones for SoChip,
   Sipeed, Kontron, B&R Industrial Automation GmbH, and Espressif
 
 - Add Mediatek UART RX wakeup support to binding
 
 - Add reset to ST UART binding
 
 - Remove some Linuxisms from the endianness common-properties.txt
   binding
 
 - Make the flattened DT read-only after init
 
 - Ignore disabled reserved memory nodes
 
 - Clean-up some dead code in FDT functions
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Merge tag 'devicetree-for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux

Pull Devicetree updates from Rob Herring:

 - DT binding schema examples are now validated against the schemas.
   Various examples are fixed due to that.

 - Sync dtc with upstream version v1.5.0-30-g702c1b6c0e73

 - Initial schemas for networking bindings. This includes ethernet, phy
   and mdio common bindings with several Allwinner and stmmac converted
   to the schema.

 - Conversion of more Arm top-level SoC/board bindings to DT schema

 - Conversion of PSCI binding to DT schema

 - Rework Arm CPU schema to coexist with other CPU schemas

 - Add a bunch of missing vendor prefixes and new ones for SoChip,
   Sipeed, Kontron, B&R Industrial Automation GmbH, and Espressif

 - Add Mediatek UART RX wakeup support to binding

 - Add reset to ST UART binding

 - Remove some Linuxisms from the endianness common-properties.txt
   binding

 - Make the flattened DT read-only after init

 - Ignore disabled reserved memory nodes

 - Clean-up some dead code in FDT functions

* tag 'devicetree-for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: (56 commits)
  dt-bindings: vendor-prefixes: add Sipeed
  dt-bindings: vendor-prefixes: add SoChip
  dt-bindings: 83xx-512x-pci: Drop cell-index property
  dt-bindings: serial: add documentation for Rx in-band wakeup support
  dt-bindings: arm: Convert RDA Micro board/soc bindings to json-schema
  of: unittest: simplify getting the adapter of a client
  of/fdt: pass early_init_dt_reserve_memory_arch() with bool type nomap
  of/platform: Drop superfluous cast in of_device_make_bus_id()
  dt-bindings: usb: ehci: Fix example warnings
  dt-bindings: net: Use phy-mode instead of phy-connection-type
  dt-bindings: simple-framebuffer: Add requirement for pipelines
  dt-bindings: display: Fix simple-framebuffer example
  dt-bindings: net: mdio: Add child nodes
  dt-bindings: net: mdio: Add address and size cells
  dt-bindings: net: mdio: Add a nodename pattern
  dt-bindings: mtd: sunxi-nand: Drop 'maxItems' from child 'reg' property
  dt-bindings: arm: Limit cpus schema to only check Arm 'cpu' nodes
  dt-bindings: backlight: lm3630a: correct schema validation
  dt-bindings: net: dwmac: Deprecate the PHY reset properties
  dt-bindings: net: sun8i-emac: Convert the binding to a schemas
  ...
2019-07-11 18:35:30 -07:00
Mauro Carvalho Chehab b693d0b372 docs: arm64: convert docs to ReST and rename to .rst
The documentation is in a format that is very close to ReST format.

The conversion is actually:
  - add blank lines in order to identify paragraphs;
  - fixing tables markups;
  - adding some lists markups;
  - marking literal blocks;
  - adjust some title markups.

At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2019-06-14 14:20:27 -06:00