Age | Commit message (Collapse) | Author | Files | Lines |
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Remove the 'code-block:: none' labels and switch to the shorter '::' to
reduce noise.
Remove a unneeded level of indentation, as that reduces the chance that
readers have to scroll sideways in some of the code blocks.
No text changes. Rendered html output looks like before, except for the
different level of indentation.
CC: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/755afbeafc8e1457154cb4b30ff4397f34326679.1714367921.git.linux@leemhuis.info
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Fine-tuning:
* s/Linus' tree/Linux mainline/, as mainline is the term used elsewhere
in the document.
* Provide a better example for the 'delayed backporting' case that uses
a fixed rather than a relative reference point, which makes it easier
to handle for the stable team.
Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/0a120573ea827aee12d45e7bd802ba85c09884da.1714367921.git.linux@leemhuis.info
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Explain the general concept once in the intro to keep things somewhat
shorter in the individual points.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/106e21789e2bf02d174e1715b49cd4d30886d51f.1714367921.git.linux@leemhuis.info
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Support of kprobes and kretprobes for riscv was introduced 3 years ago
by the following change:
commit c22b0bcb1dd0 ("riscv: Add kprobes supported")
Add riscv to the list of supported architectures.
Signed-off-by: Ivan Orlov <ivan.orlov@codethink.co.uk>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240429155735.68781-1-ivan.orlov@codethink.co.uk
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Fix spelling and grammar in Docs descriptions
Signed-off-by: Remington Brasga <rbrasga@uci.edu>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240429225527.2329-1-rbrasga@uci.edu
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Running "make htmldocs" on a newly installed Sphinx 7.3.7 ends up in
a build error:
Sphinx parallel build error:
AttributeError: module 'docutils.nodes' has no attribute 'reprunicode'
docutils 0.21 has removed nodes.reprunicode, quote from release note [1]:
* Removed objects:
docutils.nodes.reprunicode, docutils.nodes.ensure_str()
Python 2 compatibility hacks
Sphinx 7.3.0 supports docutils 0.21 [2]:
kernel_include.py, whose origin is misc.py of docutils, uses reprunicode.
Upstream docutils removed the offending line from the corresponding file
(docutils/docutils/parsers/rst/directives/misc.py) in January 2022.
Quoting the changelog [3]:
Deprecate `nodes.reprunicode` and `nodes.ensure_str()`.
Drop uses of the deprecated constructs (not required with Python 3).
Do the same for kernel_include.py.
Tested against:
- Sphinx 2.4.5 (docutils 0.17.1)
- Sphinx 3.4.3 (docutils 0.17.1)
- Sphinx 5.3.0 (docutils 0.18.1)
- Sphinx 6.2.1 (docutils 0.19)
- Sphinx 7.2.6 (docutils 0.20.1)
- Sphinx 7.3.7 (docutils 0.21.2)
Link: http://www.docutils.org/RELEASE-NOTES.html#release-0-21-2024-04-09 [1]
Link: https://www.sphinx-doc.org/en/master/changes.html#release-7-3-0-released-apr-16-2024 [2]
Link: https://github.com/docutils/docutils/commit/c8471ce47a24 [3]
Signed-off-by: Akira Yokosawa <akiyks@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/faf5fa45-2a9d-4573-9d2e-3930bdc1ed65@gmail.com
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Catch up the update made in commit e49ad8530de9 ("CREDITS, MAINTAINERS,
docs/process/howto: Update man-pages' maintainer").
Signed-off-by: Akira Yokosawa <akiyks@gmail.com>
Cc: Tsugikazu Shibata <shibata@linuxfoundation.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240502085610.111739-1-akiyks@gmail.com
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Translation for the following patches
commit 6e55b1cbf05d ("docs: try to encourage (netdev?) reviewers")
commit e49ad8530de9 ("CREDITS, MAINTAINERS, docs/process/howto: Update man-pages' maintainer")
commit 44ac5abac86b ("Documentation/security-bugs: move from admin-guide/ to process/")
commit 5a602de99797 ("Add .editorconfig file for basic formatting")
commit 129027b78c49 ("docs: deprecated.rst: Update an example")
commit efc0a7cfe9ec ("Docs/process/changes: Consolidate NFS-utils update links")
commit 383f30882197 ("Docs/process/changes: Replace http:// with https://")
commit 80fe9e51510b ("rust: upgrade to Rust 1.74.1")
commit c584476d477e ("doc: Add tar requirement to changes.rst")
commit b230235b3865 ("docs: Set minimal gtags / GNU GLOBAL version to 6.6.5")
commit 3e893e16af55 ("docs: Raise the minimum Sphinx requirement to 2.4.4")
commit 08ab786556ff ("rust: bindgen: upgrade to 0.65.1")
commit 185ea7676ef3 ("Documentation: coding-style: Update syntax highlighting for code-blocks")
commit 932be49b71e7 ("Documentation: coding-style: Fix indentation in code-blocks")
commit 5c7944ca7b13 ("coding-style: Add guidance to prefer dev_dbg")
commit c15ec3d1a287 ("Documentation: doc-guide: use '%' constant indicator in Return: examples")
commit 329ac9af902e ("docs: submitting-patches: Discuss interleaved replies")
commit 5382774515d4 ("(docs-next) A reworked process/index.rst")
Signed-off-by: Federico Vaga <federico.vaga@vaga.pv.it>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240316225400.22590-1-federico.vaga@vaga.pv.it
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Translate process/cve.rst into Chinese and add it to
Documentation/translations/zh_CN directory.
Signed-off-by: Dongliang Mu <dzm91@hust.edu.cn>
Reviewed-by: Alex Shi <alexs@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240422041115.2439166-1-dzm91@hust.edu.cn
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In the near future, I will not have access to the email address I used as
maintainer of a number of things, mostly in the documentation. Update that
address to my personal email address (see Link) so I can continue
contributing and update .mailmap.
Link: https://lore.kernel.org/all/BL1PR12MB58749FF2BFEDB817DE1FE6CBF82A2@BL1PR12MB5874.namprd12.prod.outlook.com/
Signed-off-by: Carlos Bilbao <carlos.bilbao@amd.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/139b8cab-009c-4688-be41-c4c526532ea1@amd.com
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kernel-doc emits a warning on struct_group_tagged() if you describe your
struct group member:
include/net/libeth/rx.h:69: warning: Excess struct member 'fp' description in 'libeth_fq'
The code:
/**
* struct libeth_fq - structure representing a buffer queue
* @fp: hotpath part of the structure
* @pp: &page_pool for buffer management
[...]
*/
struct libeth_fq {
struct_group_tagged(libeth_fq_fp, fp,
struct page_pool *pp;
[...]
);
When a struct_group_tagged() is encountered, we need to build a
`struct TAG NAME;` from it, so that it will be treated as a valid
embedded struct.
Decouple the regex and do the replacement there. As far as I can see,
this doesn't produce any new warnings on the current mainline tree.
Reported-by: Jakub Kicinski <kuba@kernel.org>
Closes: https://lore.kernel.org/netdev/20240405212513.0d189968@kernel.org
Fixes: 50d7bd38c3aa ("stddef: Introduce struct_group() helper macro")
Signed-off-by: Kees Cook <keescook@chromium.org>
Co-developed-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240411093208.2483580-1-aleksander.lobakin@intel.com
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Commit 1e596d5eff3d ("docs: Detect variable fonts and suggest denylisting
them") adds the new script check-variable-fonts.sh and intends to refer to
it in the DOCUMENTATION section in MAINTAINERS. However, the file entry
refers to scripts/check-variable-font.sh. Note the missing "s".
Hence, ./scripts/get_maintainer.pl --self-test=patterns complains about a
broken reference.
Repair this new file entry in the DOCUMENTATION section.
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@redhat.com>
Reviewed-by: Akira Yokosawa <akiyks@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240417101429.240495-1-lukas.bulwahn@redhat.com
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Translate dev-tools/kcov into Chinese and add it in
dev-tools/zh_CN/index.rst.
Signed-off-by: Haoyang Liu <tttturtleruss@hust.edu.cn>
Reviewed-by: Yanteng Si <siyanteng@loongson.cn>
Reviewed-by: Alex Shi <alexs@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240421142021.19504-1-tttturtleruss@hust.edu.cn
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Commit 839195352d82 ("mm/shuffle: remove dynamic reconfiguration")
removed the dynamic reconfiguration capabilities from the shuffle page
allocator. This means that, now, we don't have any perspective of an
"autodetection of memory-side-cache" that triggers the enablement of the
shuffle page allocator.
Therefore, let the documentation reflect that the only way to enable
the shuffle page allocator is by setting `page_alloc.shuffle=1`.
Signed-off-by: Maíra Canal <mcanal@igalia.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240422142007.1062231-1-mcanal@igalia.com
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sched_core_share_pid() copies the cookie to userspace with
put_user(id, (u64 __user *)uaddr), expecting 64 bits of space.
The "unsigned long" datatype that is documented in core-scheduling.rst
however is only 32 bits large on 32 bit architectures.
Document "unsigned long long" as the correct data type that is always
64bits large.
This matches what the selftest cs_prctl_test.c has been doing all along.
Fixes: 0159bb020ca9 ("Documentation: Add usecases, design and interface for core scheduling")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/util-linux/df7a25a0-7923-4f8b-a527-5e6f0064074d@t-8ch.de/
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Chris Hyser <chris.hyser@oracle.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240423-core-scheduling-cookie-v1-1-5753a35f8dfc@weissschuh.net
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Translate dev-tools/kmemleak.rst into Chinese and add it into
zh_CN/dev-tools/index.rst.
Signed-off-by: Haoyang Liu <tttturtleruss@hust.edu.cn>
Reviewed-by: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240406083643.5056-1-tttturtleruss@hust.edu.cn
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Quoting of the '"no regressions" rule' expression differs between
occurrences, sometimes being presented as '"no regressions rule"'. Unify
the quoting using the first form which seems semantically correct or is
at least used dominantly, albeit marginally.
One of the occurrences is obviously missing the 'rule' part -- add it.
Signed-off-by: Karel Balej <balejk@matfyz.cz>
Reviewed-by: Thorsten Leemhuis <linux@leemhuis.info>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240328194342.11760-2-balejk@matfyz.cz
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Fedora and openSUSE has started deploying "variable font" [1] format
Noto CJK fonts [2, 3]. "CJK" here stands for "Chinese, Japanese,
and Korean".
Unfortunately, XeTeX/XeLaTeX doesn't understand those fonts for
historical reasons and builds of translations.pdf end up in errors
if such fonts are present on the build host.
To help developers work around the issue, add a script to check the
presence of "variable font" Noto CJK fonts and to emit suggestions.
The script is invoked in the error path of "make pdfdocs" so that the
suggestions are made only when a PDF build actually fails.
The first suggestion is to denylist those "variable font" files by
activating a per-user and command-local fontconfig setting.
For further info and backgrounds, please refer to the header comment
of scripts/check-variable-font.sh newly added in this commit.
Link: [1] https://en.wikipedia.org/wiki/Variable_font
Link: [2] https://fedoraproject.org/wiki/Changes/Noto_CJK_Variable_Fonts
Link: [3] https://build.opensuse.org/request/show/1157217
Reported-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/8734tqsrt7.fsf@meer.lwn.net/
Reported-by: Иван Иванович <relect@bk.ru>
Link: https://lore.kernel.org/linux-doc/1708585803.600323099@f111.i.mail.ru/
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Akira Yokosawa <akiyks@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240406020416.25096-1-akiyks@gmail.com
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Translate dev-tools/ubsan.rst into Chinese, add it into
zh_CN/dev-tools/index.rst.
Signed-off-by: Dongliang Mu <dzm91@hust.edu.cn>
Reviewed-by: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240302140058.1527765-1-dzm91@hust.edu.cn
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Translate Documentation/process/2.Process.rst into Spanish
Signed-off-by: Avadhut Naik <avadhut.naik@amd.com>
Reviewed-by: Carlos Bilbao <carlos.bilbao@amd.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240305221839.2764380-5-avadhut.naik@amd.com
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Translate Documentation/process/1.Intro.rst into Spanish
In order to avoid broken links in the translated document, empty files
have been created for documents which have not yet been translated.
Signed-off-by: Avadhut Naik <avadhut.naik@amd.com>
Reviewed-by: Carlos Bilbao <carlos.bilbao@amd.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240305221839.2764380-4-avadhut.naik@amd.com
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Translate Documentation/process/development-process.rst into Spanish
Signed-off-by: Avadhut Naik <avadhut.naik@amd.com>
Reviewed-by: Carlos Bilbao <carlos.bilbao@amd.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240305221839.2764380-3-avadhut.naik@amd.com
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Commit 329ac9af902e (docs: submitting-patches: Discuss interleaved replies)
updates the original Documentation/process/submitting-patches.rst file.
Translate and add the updates to its corresponding version in Spanish.
Signed-off-by: Avadhut Naik <avadhut.naik@amd.com>
Reviewed-by: Carlos Bilbao <carlos.bilbao@amd.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240305221839.2764380-2-avadhut.naik@amd.com
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Use the correct relative pronoun.
Signed-off-by: Sarat Mandava <mandavasarat@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240321112757.17502-1-mandavasarat@gmail.com
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- ReStructured Text should be exactly reStructuredText
- "reStructuredText" is ONE word, not two! according to https://docutils.sourceforge.io/rst.html
Signed-off-by: Maki Hatano <Maki.Y.Hatano@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240323062141.14863-1-Maki.Y.Hatano@gmail.com
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Extend commit 84b4cc8189f2 ("docs: scripts: sphinx-pre-install: Fix
building docs with pyyaml package") and add pyyaml as an optional
package to Mageia, ArchLinux, and Gentoo.
The Python module pyyaml is required to build the docs, but it is only
listed in Documentation/sphinx/requirements.txt and is therefore missing
when Sphinx is installed as a package and not via pip/pypi.
Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240323125837.2022-2-thorsten.blum@toblux.com
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On Arch Linux, xelatex is installed in the texlive-xetex package.
Signed-off-by: Li Hua <lihua@email.com>
Link: https://lore.kernel.org/r/20240326104515.40346-1-lihua@email.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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The updates from commit ae67ee6c5e1d5b6a ("docs: fix Co-Developed-by
docs") in v5.0 were never applied to the Chinese translations.
In addition:
- "Cc" used wrong case,
- "Co-developed-by" lacked a dash,
- "Signed-off-by" was misspelled.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Hu Haowen <2023002089@link.tyut.edu.cn>
Reviewed-by: Alex Shi <alexs@kernel.org>
Reviewed-by: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/22892a8ab5c17d7121ef5b85f7d18d8b1f41e434.1711715655.git.geert+renesas@glider.be
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There are bunch of codes in driver like
if (dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64)))
dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32))
Actually it is wrong because if dma_set_mask_and_coherent(64) fails,
dma_set_mask_and_coherent(32) will fail for the same reason.
And dma_set_mask_and_coherent(64) never returns failure.
According to the definition of dma_set_mask(), it indicates the width of
address that device DMA can access. If it can access 64-bit address, it
must access 32-bit address inherently. So only need set biggest address
width.
See below code fragment:
dma_set_mask(mask)
{
mask = (dma_addr_t)mask;
if (!dev->dma_mask || !dma_supported(dev, mask))
return -EIO;
arch_dma_set_mask(dev, mask);
*dev->dma_mask = mask;
return 0;
}
dma_supported() will call dma_direct_supported or iommux's dma_supported
call back function.
int dma_direct_supported(struct device *dev, u64 mask)
{
u64 min_mask = (max_pfn - 1) << PAGE_SHIFT;
/*
* Because 32-bit DMA masks are so common we expect every architecture
* to be able to satisfy them - either by not supporting more physical
* memory, or by providing a ZONE_DMA32. If neither is the case, the
* architecture needs to use an IOMMU instead of the direct mapping.
*/
if (mask >= DMA_BIT_MASK(32))
return 1;
...
}
The iommux's dma_supported() actually means iommu requires devices's
minimized dma capability.
An example:
static int sba_dma_supported( struct device *dev, u64 mask)()
{
...
* check if mask is >= than the current max IO Virt Address
* The max IO Virt address will *always* < 30 bits.
*/
return((int)(mask >= (ioc->ibase - 1 +
(ioc->pdir_size / sizeof(u64) * IOVP_SIZE) )));
...
}
1 means supported. 0 means unsupported.
Correct document to make it more clear and provide correct sample code.
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
[jc: fixed then/than typo]
Link: https://lore.kernel.org/r/20240401174159.642998-1-Frank.Li@nxp.com
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Format the shell commands as code block to keep the documentation in the
same style
Signed-off-by: Weiji Wang <nebclllo0444@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240319114253.2647-1-nebclllo0444@gmail.com
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kernel-parameters.txt incorrectly states that workings of
kernel.tracepoint_printk sysctl depends on "tracepoint_printk kernel
cmdline option", this is a bit misleading for new users since the actual
cmdline option name is tp_printk.
Fixes: 0daa2302968c ("tracing: Add tp_printk cmdline to have tracepoints go to printk()")
Signed-off-by: Vitaly Chikunov <vt@altlinux.org>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240323231704.1217926-1-vt@altlinux.org
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kernel-doc doesn't handle bitfields that are specified with symbolic
name, e.g. u32 cs_index_mask : SPI_CS_CNT_MAX
This results in the following warnings when running `make htmldocs`:
include/linux/spi/spi.h:246: warning: Function parameter or struct member 'cs_index_mask:SPI_CS_CNT_MAX' not described in 'spi_device'
include/linux/spi/spi.h:246: warning: Excess struct member 'cs_index_mask' description in 'spi_device'
Update the regexp for bitfields to accept all word chars, not just
digits.
Signed-off-by: Donald Hunter <donald.hunter@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240326173825.99190-1-donald.hunter@gmail.com
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I could not remember the name of this system and it's pretty hard to
find without the right keywords. I had to ask an LLM!
Drop a breadcrumb to help people find it in the future.
Signed-off-by: Brendan Jackman <jackmanb@google.com>
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240328124947.2107524-1-jackmanb@google.com
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Check if get_next_variable() is actually valid pointer before
calling it. In kdump kernel this method is set to NULL that causes
panic during the kexec-ed kernel boot.
Tested with QEMU and OVMF firmware.
Fixes: bad267f9e18f ("efi: verify that variable services are supported")
Signed-off-by: Oleksandr Tymoshenko <ovt@google.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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Clearing BSS should only be done once, at the very beginning.
efi_pe_entry() is the entrypoint from the firmware, which may not clear
BSS and so it is done explicitly. However, efi_pe_entry() is also used
as an entrypoint by the mixed mode startup code, in which case BSS will
already have been cleared, and doing it again at this point will corrupt
global variables holding the firmware's GDT/IDT and segment selectors.
So make the memset() conditional on whether the EFI stub is running in
native mode.
Fixes: b3810c5a2cc4a666 ("x86/efistub: Clear decompressor BSS in native EFI entrypoint")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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Normally, the EFI stub calls into the EFI boot services using the stack
that was live when the stub was entered. According to the UEFI spec,
this stack needs to be at least 128k in size - this might seem large but
all asynchronous processing and event handling in EFI runs from the same
stack and so quite a lot of space may be used in practice.
In mixed mode, the situation is a bit different: the bootloader calls
the 32-bit EFI stub entry point, which calls the decompressor's 32-bit
entry point, where the boot stack is set up, using a fixed allocation
of 16k. This stack is still in use when the EFI stub is started in
64-bit mode, and so all calls back into the EFI firmware will be using
the decompressor's limited boot stack.
Due to the placement of the boot stack right after the boot heap, any
stack overruns have gone unnoticed. However, commit
5c4feadb0011983b ("x86/decompressor: Move global symbol references to C code")
moved the definition of the boot heap into C code, and now the boot
stack is placed right at the base of BSS, where any overruns will
corrupt the end of the .data section.
While it would be possible to work around this by increasing the size of
the boot stack, doing so would affect all x86 systems, and mixed mode
systems are a tiny (and shrinking) fraction of the x86 installed base.
So instead, record the firmware stack pointer value when entering from
the 32-bit firmware, and switch to this stack every time a EFI boot
service call is made.
Cc: <stable@kernel.org> # v6.1+
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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Commit 63bed9660420 ("x86/startup_64: Defer assignment of 5-level paging
global variables") moved assignment of 5-level global variables to later
in the boot in order to avoid having to use RIP relative addressing in
order to set them. However, when running with 5-level paging and SME
active (mem_encrypt=on), the variables are needed as part of the page
table setup needed to encrypt the kernel (using pgd_none(), p4d_offset(),
etc.). Since the variables haven't been set, the page table manipulation
is done as if 4-level paging is active, causing the system to crash on
boot.
While only a subset of the assignments that were moved need to be set
early, move all of the assignments back into check_la57_support() so that
these assignments aren't spread between two locations. Instead of just
reverting the fix, this uses the new RIP_REL_REF() macro when assigning
the variables.
Fixes: 63bed9660420 ("x86/startup_64: Defer assignment of 5-level paging global variables")
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/2ca419f4d0de719926fd82353f6751f717590a86.1711122067.git.thomas.lendacky@amd.com
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When running with 5-level page tables, the kernel mapping PGD entry is
updated to point to the P4D table. The assignment uses _PAGE_TABLE_NOENC,
which, when SME is active (mem_encrypt=on), results in a page table
entry without the encryption mask set, causing the system to crash on
boot.
Change the assignment to use _PAGE_TABLE instead of _PAGE_TABLE_NOENC so
that the encryption mask is set for the PGD entry.
Fixes: 533568e06b15 ("x86/boot/64: Use RIP_REL_REF() to access early_top_pgt[]")
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/8f20345cda7dbba2cf748b286e1bc00816fe649a.1711122067.git.thomas.lendacky@amd.com
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This one is the regular laptop CPU.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20240322161725.195614-1-tony.luck@intel.com
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Commit 672365477ae8 ("x86/fpu: Update XFD state where required") and
commit 8bf26758ca96 ("x86/fpu: Add XFD state to fpstate") introduced a
per CPU variable xfd_state to keep the MSR_IA32_XFD value cached, in
order to avoid unnecessary writes to the MSR.
On CPU hotplug MSR_IA32_XFD is reset to the init_fpstate.xfd, which
wipes out any stale state. But the per CPU cached xfd value is not
reset, which brings them out of sync.
As a consequence a subsequent xfd_update_state() might fail to update
the MSR which in turn can result in XRSTOR raising a #NM in kernel
space, which crashes the kernel.
To fix this, introduce xfd_set_state() to write xfd_state together
with MSR_IA32_XFD, and use it in all places that set MSR_IA32_XFD.
Fixes: 672365477ae8 ("x86/fpu: Update XFD state where required")
Signed-off-by: Adamos Ttofari <attofari@amazon.de>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240322230439.456571-1-chang.seok.bae@intel.com
Closes: https://lore.kernel.org/lkml/20230511152818.13839-1-attofari@amazon.de
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The memory bandwidth software controller uses 2^20 units rather than
10^6. See mbm_bw_count() which computes bandwidth using the "SZ_1M"
Linux define for 0x00100000.
Update the documentation to use MiB when describing this feature.
It's too late to fix the mount option "mba_MBps" as that is now an
established user interface.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20240322182016.196544-1-tony.luck@intel.com
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The APIC address is registered twice. First during the early detection and
afterwards when actually scanning the table for APIC IDs. The APIC and
topology core warn about the second attempt.
Restrict it to the early detection call.
Fixes: 81287ad65da5 ("x86/apic: Sanitize APIC address setup")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20240322185305.297774848@linutronix.de
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If there is no local APIC enumerated and registered then the topology
bitmaps are empty. Therefore, topology_init_possible_cpus() will die with
a division by zero exception.
Prevent this by registering a fake APIC id to populate the topology
bitmap. This also allows to use all topology query interfaces
unconditionally. It does not affect the actual APIC code because either
the local APIC address was not registered or no local APIC could be
detected.
Fixes: f1f758a80516 ("x86/topology: Add a mechanism to track topology via APIC IDs")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20240322185305.242709302@linutronix.de
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The local APICs have not yet been enumerated so the logical ID evaluation
from the topology bitmaps does not work and would return an error code.
Skip the evaluation during the early boot CPUID evaluation and only apply
it on the final run.
Fixes: 380414be78bf ("x86/cpu/topology: Use topology logical mapping mechanism")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20240322185305.186943142@linutronix.de
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The boot sequence evaluates CPUID information twice:
1) During early boot
2) When finalizing the early setup right before
mitigations are selected and alternatives are patched.
In both cases the evaluation is stored in boot_cpu_data, but on UP the
copying of boot_cpu_data to the per CPU info of the boot CPU happens
between #1 and #2. So any update which happens in #2 is never propagated to
the per CPU info instance.
Consolidate the whole logic and copy boot_cpu_data right before applying
alternatives as that's the point where boot_cpu_data is in it's final
state and not supposed to change anymore.
This also removes the voodoo mb() from smp_prepare_cpus_common() which
had absolutely no purpose.
Fixes: 71eb4893cfaf ("x86/percpu: Cure per CPU madness on UP")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20240322185305.127642785@linutronix.de
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The current message for telling the user that their compiler does not
support the counted_by attribute in the FAM_BOUNDS test does not make
much sense either grammatically or semantically. Fix it to make it
correct in both aspects.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20240321-lkdtm-improve-lack-of-counted_by-msg-v1-1-0fbf7481a29c@kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
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The norm should be flexible array structures with __counted_by
annotations, so DEFINE_FLEX() is updated to expect that. Rename
the non-annotated version to DEFINE_RAW_FLEX(), and update the
few existing users. Additionally add selftests for the macros.
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20240306235128.it.933-kees@kernel.org
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
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Following warning is sometimes observed while booting my servers:
[ 3.594838] DMA: preallocated 4096 KiB GFP_KERNEL pool for atomic allocations
[ 3.602918] swapper/0: page allocation failure: order:10, mode:0xcc1(GFP_KERNEL|GFP_DMA), nodemask=(null),cpuset=/,mems_allowed=0-1
...
[ 3.851862] DMA: preallocated 1024 KiB GFP_KERNEL|GFP_DMA pool for atomic allocation
If 'nokaslr' boot option is set, the warning always happens.
On x86, ZONE_DMA is small zone at the first 16MB of physical address
space. When this problem happens, most of that space seems to be used by
decompressed kernel. Thereby, there is not enough space at DMA_ZONE to
meet the request of DMA pool allocation.
The commit 2f77465b05b1 ("x86/efistub: Avoid placing the kernel below
LOAD_PHYSICAL_ADDR") tried to fix this problem by introducing lower
bound of allocation.
But the fix is not complete.
efi_random_alloc() allocates pages by following steps.
1. Count total available slots ('total_slots')
2. Select a slot ('target_slot') to allocate randomly
3. Calculate a starting address ('target') to be included target_slot
4. Allocate pages, which starting address is 'target'
In step 1, 'alloc_min' is used to offset the starting address of memory
chunk. But in step 3 'alloc_min' is not considered at all. As the
result, 'target' can be miscalculated and become lower than 'alloc_min'.
When KASLR is disabled, 'target_slot' is always 0 and the problem
happens everytime if the EFI memory map of the system meets the
condition.
Fix this problem by calculating 'target' considering 'alloc_min'.
Cc: linux-efi@vger.kernel.org
Cc: Tom Englund <tomenglund26@gmail.com>
Cc: linux-kernel@vger.kernel.org
Fixes: 2f77465b05b1 ("x86/efistub: Avoid placing the kernel below LOAD_PHYSICAL_ADDR")
Signed-off-by: Kazuma Kondo <kazuma-kondo@nec.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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Read from an unsafe address with copy_from_kernel_nofault() in
arch_adjust_kprobe_addr() because this function is used before checking
the address is in text or not. Syzcaller bot found a bug and reported
the case if user specifies inaccessible data area,
arch_adjust_kprobe_addr() will cause a kernel panic.
[ mingo: Clarified the comment. ]
Fixes: cc66bb914578 ("x86/ibt,kprobes: Cure sym+0 equals fentry woes")
Reported-by: Qiang Zhang <zzqq0103.hey@gmail.com>
Tested-by: Jinghao Jia <jinghao7@illinois.edu>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/171042945004.154897.2221804961882915806.stgit@devnote2
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