Commit Graph

12 Commits

Author SHA1 Message Date
Alexandre Ghiti
e79be4bea5 Documentation: riscv: Add early boot document
This document describes the constraints and requirements of the early
boot process in a RISC-V kernel.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Sunil V L <sunilvl@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Song Shuai <songshuaishuai@tinylab.org>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20230817130734.10387-2-alexghiti@rivosinc.com
2023-08-18 11:04:05 -06:00
Palmer Dabbelt
5177978ee0
RISC-V: Document the ISA string parsing rules for ACPI
We've had a ton of issues around the ISA string parsing rules elsewhere
in RISC-V, so let's at least be clear about what the rules are so we can
try and avoid more issues.

Link: https://lore.kernel.org/r/CAK9=C2Vy-4V9kgnga98tiC3TeHkR2LFPakyBbS8s_h3_Z=ieyQ@mail.gmail.com/
Link: https://lore.kernel.org/r/20230629031705.15575-1-palmer@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-07-06 10:25:17 -07:00
Andy Chiu
04a4722eee
riscv: Add documentation for Vector
This patch add a brief documentation of the userspace interface in
regard to the RISC-V Vector extension.

Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Reviewed-by: Greentime Hu <greentime.hu@sifive.com>
Reviewed-by: Vincent Chen <vincent.chen@sifive.com>
Co-developed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Link: https://lore.kernel.org/r/20230605110724.21391-26-andy.chiu@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-08 07:16:57 -07:00
Evan Green
ea3de9ce8a
RISC-V: Add a syscall for HW probing
We don't have enough space for these all in ELF_HWCAP{,2} and there's no
system call that quite does this, so let's just provide an arch-specific
one to probe for hardware capabilities.  This currently just provides
m{arch,imp,vendor}id, but with the key-value pairs we can pass more in
the future.

Co-developed-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Evan Green <evan@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Tested-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Reviewed-by: Paul Walmsley <paul.walmsley@sifive.com>
Link: https://lore.kernel.org/r/20230407231103.2622178-3-evan@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-04-18 15:48:14 -07:00
Palmer Dabbelt
06267eb2de
doc: RISC-V: Document that misaligned accesses are supported
The RISC-V ISA manual used to mandate that misaligned accesses were
supported in user mode, but that requirement was removed in 2018 via
riscv-isa-manual commit 61cadb9 ("Provide new description of misaligned
load/store behavior compatible with privileged architecture.").  Since
the Linux uABI was already frozen at that point it's just been demoted
to part of the uABI, but that was never written down.

Link: https://lore.kernel.org/r/20220728210715.17214-1-palmer@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-10-12 08:58:10 -07:00
Bagas Sanjaya
8933e7f2e3
Documentation: riscv: remove non-existent directory from table of contents
This subdir no longer exists: it was there to document some of the
quirks and paths forward for handling them, but those have been dealt
with as of Atish's recent patch set.

Fixes: 23b1f18326 ("Documentation: riscv: Remove the old documentation")
Link: https://lore.kernel.org/linux-next/20220329133412.591d6882@canb.auug.org.au/
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
[Palmer: commit text]
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-03-31 16:18:56 -07:00
Alexandre Ghiti
2a433cf8f3
Documentation: riscv: Add documentation that describes the VM layout
This new document presents the RISC-V virtual memory layout and is based
one the x86 one: it describes the different limits of the different regions
of the virtual address space.

Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-04-26 08:25:05 -07:00
Mauro Carvalho Chehab
ed13a92d0f docs: archis: add a per-architecture features list
Add a feature list matrix for each architecture to their
respective Kernel books.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/9c39d4dd93e05c0008205527d2c3450912f029ed.1606748711.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-12-03 15:10:15 -07:00
Paul Walmsley
0e194d9da1 Documentation: riscv: add patch acceptance guidelines
Formalize, in kernel documentation, the patch acceptance policy for
arch/riscv.  In summary, it states that as maintainers, we plan to
only accept patches for new modules or extensions that have been
frozen or ratified by the RISC-V Foundation.

We've been following these guidelines for the past few months.  In the
meantime, we've received quite a bit of feedback that it would be
helpful to have these guidelines formally documented.

Based on a suggestion from Matthew Wilcox, we also add a link to this
file to Documentation/process/index.rst, to make this document easier
to find.  The format of this document has also been changed to align
to the format outlined in the maintainer entry profiles, in accordance
with comments from Jon Corbet and Dan Williams.

Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Krste Asanovic <krste@berkeley.edu>
Cc: Andrew Waterman <waterman@eecs.berkeley.edu>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
2020-01-04 21:49:01 -08:00
Mauro Carvalho Chehab
638b642f82 docs: riscv: convert boot-image-header.txt to ReST
Convert this small file to ReST format by:
   - Using a proper markup for the document title;
   - marking a code block as such;
   - use tags for Author and date;
   - use tables for bit map fields.

While here, fix a broken reference for a document with is
planned but is not here yet.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2019-07-31 13:01:47 -06:00
Mauro Carvalho Chehab
159a5e78bd docs: add arch doc directories to the index
Now that several arch documents were converted to ReST,
add their indexes to Documentation/index.rst and remove the
:orphan:  from them.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
2019-07-15 11:03:01 -03:00
Mauro Carvalho Chehab
bdf3a950fb docs: riscv: convert docs to ReST and rename to *.rst
The conversion here is trivial:
 - Adjust the document title's markup
 - Do some whitespace alignment;
 - mark literal blocks;
 - Use ReST way to markup indented lists.

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 14:31:32 -06:00