This option was never meant to be used in production because it solely
clears the X86_FEATURE kernel-internal representation of what CPUID bits
it has detected and doesn't do any *proper* feature disablement like
clearing CR4.CET in the user shadow stack case, for example.
So remove its documentation so that it doesn't get used in production
and people get silly ideas. It is meant strictly for debugging; and if
a chicken bit for properly disabling a feature is warranted, then that
would need proper enablement.
No functional changes.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Mathias Krause <minipli@grsecurity.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://patch.msgid.link/20260520202508.160112-1-bp@kernel.org
Pull misc x86 updates from Dave Hansen:
"The usual smattering of x86/misc changes.
The IPv6 patch in here surprised me in a couple of ways. First, the
function it inlines is able to eat a lot more CPU time than I would
have expected. Second, the inlining does not seem to bloat the kernel,
at least in the configs folks have tested.
- Inline x86-specific IPv6 checksum helper
- Update IOMMU docs to use stable identifiers
- Print unhashed pointers on fatal stack overflows"
* tag 'x86_misc_for_7.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/traps: Print unhashed pointers on stack overflow
Documentation/x86: Update IOMMU spec references to use stable identifiers
x86/lib: Inline csum_ipv6_magic()
Pull documentation updates from Jonathan Corbet:
"A slightly calmer cycle for docs this time around, though there is
still a fair amount going on, including:
- Some signs of life on the long-moribund Japanese translation
- Documentation on policies around the use of generative tools for
patch submissions, and a separate document intended for consumption
by generative tools
- The completion of the move of the documentation tools to
tools/docs. For now we're leaving a /scripts/kernel-doc symlink
behind to avoid breaking scripts
- Ongoing build-system work includes the incorporation of
documentation in Python code, better support for documenting
variables, and lots of improvements and fixes
- Automatic linking of man-page references -- cat(1), for example --
to the online pages in the HTML build
...and the usual array of typo fixes and such"
* tag 'docs-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/docs/linux: (107 commits)
doc: development-process: add notice on testing
tools: sphinx-build-wrapper: improve its help message
docs: sphinx-build-wrapper: allow -v override -q
docs: kdoc: Fix pdfdocs build for tools
docs: ja_JP: process: translate 'Obtain a current source tree'
docs: fix 're-use' -> 'reuse' in documentation
docs: ioctl-number: fix a typo in ioctl-number.rst
docs: filesystems: ensure proc pid substitutable is complete
docs: automarkup.py: Skip common English words as C identifiers
Documentation: use a source-read extension for the index link boilerplate
docs: parse_features: make documentation more consistent
docs: add parse_features module documentation
docs: jobserver: do some documentation improvements
docs: add jobserver module documentation
docs: kabi: helpers: add documentation for each "enum" value
docs: kabi: helpers: add helper for debug bits 7 and 8
docs: kabi: system_symbols: end docstring phrases with a dot
docs: python: abi_regex: do some improvements at documentation
docs: python: abi_parser: do some improvements at documentation
docs: add kabi modules documentation
...
Pull x86 platform driver fixes from Ilpo Järvinen:
- acer-wmi:
- Extend support for Acer Nitro AN515-58
- Fix missing capability check
- amd/wbrf: Fix memory leak in wbrf_record()
- asus-armoury:
- Fix GA403U* matching
- Fix FA608UM TDP data
- Add many models
- asus-wmi: Move OOBE presence check outside deprecation ifdef
- hp-bioscfg:
- Fix kernel panic in GET_INSTANCE_ID macro
- Fix kobject warnings for empty attribute names
- Correct GUID to uppercase (lowercase letter prevented autoloading
the module)
- mellanox: Fix SN5640/SN5610 LED platform data
- docs:
- alienware-wmi: Typo fix
- amd_hsmp: Fix document link
* tag 'platform-drivers-x86-v6.19-3' of git://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86: (21 commits)
platform/x86: acer-wmi: Fix missing capability check
platform/x86: acer-wmi: Extend support for Acer Nitro AN515-58
platform/x86: asus-armoury: add support for GA403WW
platform/x86: asus-armoury: keep the list ordered alphabetically
platform/x86: asus-armoury: add support for G835L
platform/x86: asus-armoury: fix ppt data for FA608UM
platform/x86: hp-bioscfg: Fix automatic module loading
platform/x86: hp-bioscfg: Fix kernel panic in GET_INSTANCE_ID macro
platform/x86: hp-bioscfg: Fix kobject warnings for empty attribute names
platform/x86: asus-wmi: fix sending OOBE at probe
platform/x86: asus-armoury: add support for FA617XT
platform/x86: asus-armoury: add support for FA401UV
platform/x86: asus-armoury: add support for GV302XV
platform/x86: asus-armoury: Add power limits for Asus G513QY
platform/x86/amd: Fix memory leak in wbrf_record()
platform/mellanox: Fix SN5640/SN5610 LED platform data
docs: fix PPR for AMD EPYC broken link
docs: alienware-wmi: fix typo
platform/x86: asus-armoury: add support for GA403UV
asus-armoury: fix ppt data for GA403U* renaming to GA403UI
...
In a vain attempt to consolidate the email zoo switch everything to the
kernel.org account.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Direct URLs to vendor specifications for Intel VT-d and AMD IOMMU
are frequently changed by vendors, leading to broken links in the
documentation.
Replace the fragile URLs with persistent identifiers, providing the
official document titles and IDs. This ensures users can locate the
relevant specifications regardless of vendor website restructuring.
Signed-off-by: Richard Lyu <richard.lyu@suse.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://patch.msgid.link/20260106052815.46114-1-richard.lyu@suse.com
Sphinx reports htmldocs warnings:
Documentation/arch/x86/boot.rst:437: ERROR: Malformed table.
Text in column margin in table line 2.
The table header defined the first column width as 2 characters ("=="),
which is too narrow for entries like "0x10" and "0x13". This caused the
text to spill into the margin, triggering a docutils parsing failure.
Fix it by extending the first column of assigned boot loader ID to 4
characters ("====") to fit the widest entries.
Fixes: 1c3377bee2 ("x86/boot/Documentation: Prefix hexadecimal literals with 0x")
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Swaraj Gaikwad <swarajgaikwad1925@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Link: https://patch.msgid.link/20251210092814.9986-1-swarajgaikwad1925@gmail.com
Pull x86 fixes from Ingo Molnar:
"Miscellaneous documentation fixes"
* tag 'x86-urgent-2025-12-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/boot/Documentation: Prefix hexadecimal literals with 0x
x86/boot/Documentation: Spell 'ID' consistently
x86/platform: Fix and extend kernel-doc comments in <asm/x86_init.h>
The x86 bootloader ID specification text uses hexadecimal
values without a 0x prefix:
D kexec-tools
E Extended (see ext_loader_type)
F Special (0xFF = undefined)
10 Reserved
11 Minimal Linux Bootloader
<http://sebastian-plotz.blogspot.de>
12 OVMF UEFI virtualization stack
13 barebox
Which beyond the ambiguity of '13' in isolation, also
made me fail a grep -wi '0xd' when I was looking for
the kexec bootloader ID definition and caused quite
a bit of head-scratching before I found out why it
didn't show up.
Furthermore, the actual explanatory text uses the 0x
prefix:
For boot loader IDs above T = 0xD, write T = 0xE to this field and
write the extended ID minus 0x10 to the ext_loader_type field.
Similarly, the ext_loader_ver field can be used to provide more than
four bits for the bootloader version.
So make it all both unambiguous, easy to grep and consistent
across the entire documentation by prefixing the IDs with 0x.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: linux-kernel@vger.kernel.org
The bootloader ID specification text uses 2 capitalization
variants for the same thing: 'id', 'ids', 'ID' and 'IDs'.
Use 'ID/IDs' consistently.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: linux-kernel@vger.kernel.org
Since the Handover Protocol was deprecated, the recommended approach is
to provide an initrd using a UEFI boot service with the
LINUX_EFI_INITRD_MEDIA_GUID device path. Documentation for the new
approach has been no more than an admonition with a link to an existing
implementation.
Provide a short explanation of this functionality, to ease future
implementations without having to reverse engineer existing ones.
[Bagas: Don't use :ref: link to EFI stub documentation and refer to
OVMF/edk2 implementation]
Signed-off-by: Hugo Osvaldo Barrera <hugo@whynothugo.nl>
Link: https://lore.kernel.org/r/20250428131206.8656-2-hugo@whynothugo.nl
Co-developed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20251013085718.27085-1-bagasdotme@gmail.com>
Pull x86 TDX updates from Dave Hansen:
"The biggest change here is making TDX and kexec play nicely together.
Before this, the memory encryption hardware (which doesn't respect
cache coherency) could write back old cachelines on top of data in the
new kernel, so kexec and TDX were made mutually exclusive. This
removes the limitation.
There is also some work to tighten up a hardware bug workaround and
some MAINTAINERS updates.
- Make TDX and kexec work together
- Skip TDX bug workaround when the bug is not present
- Update maintainers entries"
* tag 'x86_tdx_for_6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/virt/tdx: Use precalculated TDVPR page physical address
KVM/TDX: Explicitly do WBINVD when no more TDX SEAMCALLs
x86/virt/tdx: Update the kexec section in the TDX documentation
x86/virt/tdx: Remove the !KEXEC_CORE dependency
x86/kexec: Disable kexec/kdump on platforms with TDX partial write erratum
x86/virt/tdx: Mark memory cache state incoherent when making SEAMCALL
x86/sme: Use percpu boolean to control WBINVD during kexec
x86/kexec: Consolidate relocate_kernel() function parameters
x86/tdx: Skip clearing reclaimed pages unless X86_BUG_TDX_PW_MCE is present
x86/tdx: Tidy reset_pamt functions
x86/tdx: Eliminate duplicate code in tdx_clear_page()
MAINTAINERS: Add KVM mail list to the TDX entry
MAINTAINERS: Add Rick Edgecombe as a TDX reviewer
MAINTAINERS: Update the file list in the TDX entry.
Pull documentation updates from Jonathan Corbet:
"It has been a relatively busy cycle in docsland, with changes all
over:
- Bring the kernel memory-model docs into the Sphinx build in the
"literal include" mode.
- Lots of build-infrastructure work, further cleaning up long-term
kernel-doc technical debt. The sphinx-pre-install tool has been
converted to Python and updated for current systems.
- A new tool to detect when documents have been moved and generate
HTML redirects; this can be used on kernel.org (or any other site
hosting the rendered docs) to avoid breaking links.
- Automated processing of the YAML files describing the netlink
protocol.
- A significant update of the maintainer's PGP guide.
... and a seemingly endless series of typo fixes, build-problem fixes,
etc"
* tag 'docs-6.18' of git://git.lwn.net/linux: (193 commits)
Documentation/features: Update feature lists for 6.17-rc7
docs: remove cdomain.py
Documentation/process: submitting-patches: fix typo in "were do"
docs: dev-tools/lkmm: Fix typo of missing file extension
Documentation: trace: histogram: Convert ftrace docs cross-reference
Documentation: trace: histogram-design: Wrap introductory note in note:: directive
Documentation: trace: historgram-design: Separate sched_waking histogram section heading and the following diagram
Documentation: trace: histogram-design: Trim trailing vertices in diagram explanation text
Documentation: trace: histogram: Fix histogram trigger subsection number order
docs: driver-api: fix spelling of "buses".
Documentation: fbcon: Use admonition directives
Documentation: fbcon: Reindent 8th step of attach/detach/unload
Documentation: fbcon: Add boot options and attach/detach/unload section headings
docs: filesystems: sysfs: add remaining top level sysfs directory descriptions
docs: filesystems: sysfs: clarify symlink destinations in dev and bus/devices descriptions
docs: filesystems: sysfs: remove top level sysfs net directory
docs: maintainer: Fix ambiguous subheading formatting
docs: kdoc: a few more dump_typedef() tweaks
docs: kdoc: remove redundant comment stripping in dump_typedef()
docs: kdoc: remove some dead code in dump_typedef()
...
Pull x86 platform updates from Ingo Molnar:
"This adds support for the AMD hardware feedback interface (HFI), by
Perry Yuan"
* tag 'x86-platform-2025-07-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/itmt: Add debugfs file to show core priorities
platform/x86/amd: hfi: Add debugfs support
platform/x86/amd: hfi: Set ITMT priority from ranking data
cpufreq/amd-pstate: Disable preferred cores on designs with workload classification
x86/process: Clear hardware feedback history for AMD processors
platform/x86: hfi: Add power management callback
platform/x86: hfi: Add online and offline callback support
platform/x86: hfi: Init per-cpu scores for each class
platform/x86: hfi: Parse CPU core ranking data from shared memory
platform/x86: hfi: Introduce AMD Hardware Feedback Interface Driver
x86/msr-index: Add AMD workload classification MSRs
MAINTAINERS: Add maintainer entry for AMD Hardware Feedback Driver
Documentation/x86: Add AMD Hardware Feedback Interface documentation
Pull hardening updates from Kees Cook:
- Introduce and start using TRAILING_OVERLAP() helper for fixing
embedded flex array instances (Gustavo A. R. Silva)
- mux: Convert mux_control_ops to a flex array member in mux_chip
(Thorsten Blum)
- string: Group str_has_prefix() and strstarts() (Andy Shevchenko)
- Remove KCOV instrumentation from __init and __head (Ritesh Harjani,
Kees Cook)
- Refactor and rename stackleak feature to support Clang
- Add KUnit test for seq_buf API
- Fix KUnit fortify test under LTO
* tag 'hardening-v6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (22 commits)
sched/task_stack: Add missing const qualifier to end_of_stack()
kstack_erase: Support Clang stack depth tracking
kstack_erase: Add -mgeneral-regs-only to silence Clang warnings
init.h: Disable sanitizer coverage for __init and __head
kstack_erase: Disable kstack_erase for all of arm compressed boot code
x86: Handle KCOV __init vs inline mismatches
arm64: Handle KCOV __init vs inline mismatches
s390: Handle KCOV __init vs inline mismatches
arm: Handle KCOV __init vs inline mismatches
mips: Handle KCOV __init vs inline mismatch
powerpc/mm/book3s64: Move kfence and debug_pagealloc related calls to __init section
configs/hardening: Enable CONFIG_INIT_ON_FREE_DEFAULT_ON
configs/hardening: Enable CONFIG_KSTACK_ERASE
stackleak: Split KSTACK_ERASE_CFLAGS from GCC_PLUGINS_CFLAGS
stackleak: Rename stackleak_track_stack to __sanitizer_cov_stack_depth
stackleak: Rename STACKLEAK to KSTACK_ERASE
seq_buf: Introduce KUnit tests
string: Group str_has_prefix() and strstarts()
kunit/fortify: Add back "volatile" for sizeof() constants
acpi: nfit: intel: avoid multiple -Wflex-array-member-not-at-end warnings
...
In preparation for adding Clang sanitizer coverage stack depth tracking
that can support stack depth callbacks:
- Add the new top-level CONFIG_KSTACK_ERASE option which will be
implemented either with the stackleak GCC plugin, or with the Clang
stack depth callback support.
- Rename CONFIG_GCC_PLUGIN_STACKLEAK as needed to CONFIG_KSTACK_ERASE,
but keep it for anything specific to the GCC plugin itself.
- Rename all exposed "STACKLEAK" names and files to "KSTACK_ERASE" (named
for what it does rather than what it protects against), but leave as
many of the internals alone as possible to avoid even more churn.
While here, also split "prev_lowest_stack" into CONFIG_KSTACK_ERASE_METRICS,
since that's the only place it is referenced from.
Suggested-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20250717232519.2984886-1-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>
Introduce a new documentation file, `amd_hfi.rst`, which delves into the
implementation details of the AMD Hardware Feedback Interface and its
associated driver, `amd_hfi`. This documentation describes how the driver
provides hint to the OS scheduling which depends on the capability of core
performance and efficiency ranking data.
This documentation describes:
* The design of the driver
* How the driver provides hints to the OS scheduling
* How the driver interfaces with the kernel for efficiency ranking data.
Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Acked-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/20250609200518.3616080-2-superm1@kernel.org
Borislav Petkov (AMD)andIngo Molnar
Sean Christopherson
Linus Torvalds
Rhys TumeltyandJonathan Corbet
Thomas GleixnerandLinus Torvalds
Richard LyuandDave Hansen
Haiyue WangandIlpo Järvinen
Swaraj GaikwadandIngo Molnar
Hugo Osvaldo BarreraandJonathan Corbet
K Prateek NayakandIngo Molnar
Kai HuangandDave Hansen
Ranganath V NandJonathan Corbet
Kees Cook
Perry YuanandBorislav Petkov (AMD)