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author | Linus Torvalds <torvalds@linux-foundation.org> | 2023-11-01 17:11:41 -1000 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2023-11-01 17:11:41 -1000 |
commit | babe393974de0351c0e6cca50f5f84edaf8d7fa1 (patch) | |
tree | 0893d62d555675d8bcfacc5d8e3965ef377791cd /Documentation/arch/riscv/uabi.rst | |
parent | 7dc0e9c7dda66bd91eeada00d90033e3eb647fc3 (diff) | |
parent | cf63348b4c45384d02126f86676d5afc75d661a7 (diff) |
Merge tag 'docs-6.7' of git://git.lwn.net/linux
Pull documentation updates from Jonathan Corbet:
"The number of commits for documentation is not huge this time around,
but there are some significant changes nonetheless:
- Some more Spanish-language and Chinese translations
- The much-discussed documentation of the confidential-computing
threat model
- Powerpc and RISCV documentation move under Documentation/arch -
these complete this particular bit of documentation churn
- A large traditional-Chinese documentation update
- A new document on backporting and conflict resolution
- Some kernel-doc and Sphinx fixes
Plus the usual smattering of smaller updates and typo fixes"
* tag 'docs-6.7' of git://git.lwn.net/linux: (40 commits)
scripts/kernel-doc: Fix the regex for matching -Werror flag
docs: backporting: address feedback
Documentation: driver-api: pps: Update PPS generator documentation
speakup: Document USB support
doc: blk-ioprio: Bring the doc in line with the implementation
docs: usb: fix reference to nonexistent file in UVC Gadget
docs: doc-guide: mention 'make refcheckdocs'
Documentation: fix typo in dynamic-debug howto
scripts/kernel-doc: match -Werror flag strictly
Documentation/sphinx: Remove the repeated word "the" in comments.
docs: sparse: add SPDX-License-Identifier
docs/zh_CN: Add subsystem-apis Chinese translation
docs/zh_TW: update contents for zh_TW
docs: submitting-patches: encourage direct notifications to commenters
docs: add backporting and conflict resolution document
docs: move riscv under arch
docs: update link to powerpc/vmemmap_dedup.rst
mm/memory-hotplug: fix typo in documentation
docs: move powerpc under arch
PCI: Update the devres documentation regarding to pcim_*()
...
Diffstat (limited to 'Documentation/arch/riscv/uabi.rst')
-rw-r--r-- | Documentation/arch/riscv/uabi.rst | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/Documentation/arch/riscv/uabi.rst b/Documentation/arch/riscv/uabi.rst new file mode 100644 index 000000000000..8960fac42c40 --- /dev/null +++ b/Documentation/arch/riscv/uabi.rst @@ -0,0 +1,48 @@ +.. SPDX-License-Identifier: GPL-2.0 + +RISC-V Linux User ABI +===================== + +ISA string ordering in /proc/cpuinfo +------------------------------------ + +The canonical order of ISA extension names in the ISA string is defined in +chapter 27 of the unprivileged specification. +The specification uses vague wording, such as should, when it comes to ordering, +so for our purposes the following rules apply: + +#. Single-letter extensions come first, in canonical order. + The canonical order is "IMAFDQLCBKJTPVH". + +#. All multi-letter extensions will be separated from other extensions by an + underscore. + +#. Additional standard extensions (starting with 'Z') will be sorted after + single-letter extensions and before any higher-privileged extensions. + +#. For additional standard extensions, the first letter following the 'Z' + conventionally indicates the most closely related alphabetical + extension category. If multiple 'Z' extensions are named, they will be + ordered first by category, in canonical order, as listed above, then + alphabetically within a category. + +#. Standard supervisor-level extensions (starting with 'S') will be listed + after standard unprivileged extensions. If multiple supervisor-level + extensions are listed, they will be ordered alphabetically. + +#. Standard machine-level extensions (starting with 'Zxm') will be listed + after any lower-privileged, standard extensions. If multiple machine-level + extensions are listed, they will be ordered alphabetically. + +#. Non-standard extensions (starting with 'X') will be listed after all standard + extensions. If multiple non-standard extensions are listed, they will be + ordered alphabetically. + +An example string following the order is:: + + rv64imadc_zifoo_zigoo_zafoo_sbar_scar_zxmbaz_xqux_xrux + +Misaligned accesses +------------------- + +Misaligned accesses are supported in userspace, but they may perform poorly. |