kernel/Documentation/driver-api/index.rst, branch linux-rolling-stable

Merge tag 'mm-nonmm-stable-2025-12-06-11-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-12-06T22:01:20Z

Pull non-MM updates from Andrew Morton: - "panic: sys_info: Refactor and fix a potential issue" (Andy Shevchenko) fixes a build issue and does some cleanup in ib/sys_info.c - "Implement mul_u64_u64_div_u64_roundup()" (David Laight) enhances the 64-bit math code on behalf of a PWM driver and beefs up the test module for these library functions - "scripts/gdb/symbols: make BPF debug info available to GDB" (Ilya Leoshkevich) makes BPF symbol names, sizes, and line numbers available to the GDB debugger - "Enable hung_task and lockup cases to dump system info on demand" (Feng Tang) adds a sysctl which can be used to cause additional info dumping when the hung-task and lockup detectors fire - "lib/base64: add generic encoder/decoder, migrate users" (Kuan-Wei Chiu) adds a general base64 encoder/decoder to lib/ and migrates several users away from their private implementations - "rbree: inline rb_first() and rb_last()" (Eric Dumazet) makes TCP a little faster - "liveupdate: Rework KHO for in-kernel users" (Pasha Tatashin) reworks the KEXEC Handover interfaces in preparation for Live Update Orchestrator (LUO), and possibly for other future clients - "kho: simplify state machine and enable dynamic updates" (Pasha Tatashin) increases the flexibility of KEXEC Handover. Also preparation for LUO - "Live Update Orchestrator" (Pasha Tatashin) is a major new feature targeted at cloud environments. Quoting the cover letter: This series introduces the Live Update Orchestrator, a kernel subsystem designed to facilitate live kernel updates using a kexec-based reboot. This capability is critical for cloud environments, allowing hypervisors to be updated with minimal downtime for running virtual machines. LUO achieves this by preserving the state of selected resources, such as memory, devices and their dependencies, across the kernel transition. As a key feature, this series includes support for preserving memfd file descriptors, which allows critical in-memory data, such as guest RAM or any other large memory region, to be maintained in RAM across the kexec reboot. Mike Rappaport merits a mention here, for his extensive review and testing work. - "kexec: reorganize kexec and kdump sysfs" (Sourabh Jain) moves the kexec and kdump sysfs entries from /sys/kernel/ to /sys/kernel/kexec/ and adds back-compatibility symlinks which can hopefully be removed one day - "kho: fixes for vmalloc restoration" (Mike Rapoport) fixes a BUG which was being hit during KHO restoration of vmalloc() regions * tag 'mm-nonmm-stable-2025-12-06-11-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (139 commits) calibrate: update header inclusion Reinstate "resource: avoid unnecessary lookups in find_next_iomem_res()" vmcoreinfo: track and log recoverable hardware errors kho: fix restoring of contiguous ranges of order-0 pages kho: kho_restore_vmalloc: fix initialization of pages array MAINTAINERS: TPM DEVICE DRIVER: update the W-tag init: replace simple_strtoul with kstrtoul to improve lpj_setup KHO: fix boot failure due to kmemleak access to non-PRESENT pages Documentation/ABI: new kexec and kdump sysfs interface Documentation/ABI: mark old kexec sysfs deprecated kexec: move sysfs entries to /sys/kernel/kexec test_kho: always print restore status kho: free chunks using free_page() instead of kfree() selftests/liveupdate: add kexec test for multiple and empty sessions selftests/liveupdate: add simple kexec-based selftest for LUO selftests/liveupdate: add userspace API selftests docs: add documentation for memfd preservation via LUO mm: memfd_luo: allow preserving memfd liveupdate: luo_file: add private argument to store runtime state mm: shmem: export some functions to internal.h ...

vmcoreinfo: track and log recoverable hardware errors

2025-11-27T22:24:44Z

Introduce a generic infrastructure for tracking recoverable hardware errors (HW errors that are visible to the OS but does not cause a panic) and record them for vmcore consumption. This aids post-mortem crash analysis tools by preserving a count and timestamp for the last occurrence of such errors. On the other side, correctable errors, which the OS typically remains unaware of because the underlying hardware handles them transparently, are less relevant for crash dump and therefore are NOT tracked in this infrastructure. Add centralized logging for sources of recoverable hardware errors based on the subsystem it has been notified. hwerror_data is write-only at kernel runtime, and it is meant to be read from vmcore using tools like crash/drgn. For example, this is how it looks like when opening the crashdump from drgn. >>> prog['hwerror_data'] (struct hwerror_info[1]){ { .count = (int)844, .timestamp = (time64_t)1752852018, }, ... This helps fleet operators quickly triage whether a crash may be influenced by hardware recoverable errors (which executes a uncommon code path in the kernel), especially when recoverable errors occurred shortly before a panic, such as the bug fixed by commit ee62ce7a1d90 ("page_pool: Track DMA-mapped pages and unmap them when destroying the pool") This is not intended to replace full hardware diagnostics but provides a fast way to correlate hardware events with kernel panics quickly. Rare machine check exceptions—like those indicated by mce_flags.p5 or mce_flags.winchip—are not accounted for in this method, as they fall outside the intended usage scope for this feature's user base. [leitao@debian.org: add hw-recoverable-errors to toctree] Link: https://lkml.kernel.org/r/20251127-vmcoreinfo_fix-v1-1-26f5b1c43da9@debian.org Link: https://lkml.kernel.org/r/20251010-vmcore_hw_error-v5-1-636ede3efe44@debian.org Signed-off-by: Breno Leitao Suggested-by: Tony Luck Suggested-by: Shuai Xue Reviewed-by: Shuai Xue Reviewed-by: Hanjun Guo [APEI] Cc: Bjorn Helgaas Cc: Bob Moore Cc: Borislav Betkov Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: James Morse Cc: Konrad Rzessutek Wilk Cc: Len Brown Cc: Mahesh Salgaonkar Cc: Mauro Carvalho Chehab Cc: "Oliver O'Halloran" Cc: Omar Sandoval Cc: Thomas Gleinxer Signed-off-by: Andrew Morton

genpt: Add Documentation/ files

2025-11-05T08:07:07Z

Add some general description and pull in the kdoc comments from the source file to index most of the useful functions. Reviewed-by: Kevin Tian Reviewed-by: Pasha Tatashin Reviewed-by: Samiullah Khawaja Tested-by: Alejandro Jimenez Tested-by: Pasha Tatashin Signed-off-by: Jason Gunthorpe Signed-off-by: Joerg Roedel

tsm-mr: Add TVM Measurement Register support

2025-05-09T02:17:33Z

Introduce new TSM Measurement helper library (tsm-mr) for TVM guest drivers to expose MRs (Measurement Registers) as sysfs attributes, with Crypto Agility support. Add the following new APIs (see include/linux/tsm-mr.h for details): - tsm_mr_create_attribute_group(): Take on input a `struct tsm_measurements` instance, which includes one `struct tsm_measurement_register` per MR with properties like `TSM_MR_F_READABLE` and `TSM_MR_F_WRITABLE`, to determine the supported operations and create the sysfs attributes accordingly. On success, return a `struct attribute_group` instance that will typically be included by the guest driver into `miscdevice.groups` before calling misc_register(). - tsm_mr_free_attribute_group(): Free the memory allocated to the attrubute group returned by tsm_mr_create_attribute_group(). tsm_mr_create_attribute_group() creates one attribute for each MR, with names following this pattern: MRNAME[:HASH] - MRNAME - Placeholder for the MR name, as specified by `tsm_measurement_register.mr_name`. - :HASH - Optional suffix indicating the hash algorithm associated with this MR, as specified by `tsm_measurement_register.mr_hash`. Support Crypto Agility by allowing multiple definitions of the same MR (i.e., with the same `mr_name`) with distinct HASH algorithms. NOTE: Crypto Agility, introduced in TPM 2.0, allows new hash algorithms to be introduced without breaking compatibility with applications using older algorithms. CC architectures may face the same challenge in the future, needing new hashes for security while retaining compatibility with older hashes, hence the need for Crypto Agility. Signed-off-by: Cedric Xing Reviewed-by: Dan Williams Acked-by: Dionna Amalie Glaze [djbw: fixup bin_attr const conflict] Link: https://patch.msgid.link/20250509020739.882913-1-dan.j.williams@intel.com Signed-off-by: Dan Williams

Documentation: extcon: add documentation for Extcon subsystem

2024-12-08T12:59:40Z

The Extcon (External Connector) subsystem driver lacked proper documentation. This commit adds comprehensive documentation explaining the purpose, key components, and usage of the Extcon framework. The new documentation includes: - An overview of the Extcon subsystem - Descriptions of key structures - Explanations of core functions - Information on the sysfs interface - A usage example for driver developers Link: https://lore.kernel.org/lkml/20241103025436.69196-1-yesanishhere@gmail.com/ Acked-by: MyungJoo Ham Signed-off-by: anish kumar Signed-off-by: Chanwoo Choi

Documentation: add a driver API doc for the power sequencing subsystem

2024-08-22T13:29:29Z

Describe what the subsystem does, how the consumers and providers work and add API reference generated from kerneldocs. Acked-by: Jonathan Corbet Link: https://lore.kernel.org/r/20240821100818.13763-1-brgl@bgdev.pl Signed-off-by: Bartosz Golaszewski

docs: rework the driver-api top-level page

2024-01-30T20:47:53Z

Add subsections in an attempt to bring a bit order to this page; also sort most subsections into alphabetical order. With luck all this will help to prevent merge conflicts on this page due to everybody adding entries at the end. Signed-off-by: Jonathan Corbet Link: https://lore.kernel.org/r/87plxtm2oo.fsf@meer.lwn.net

Merge tag 'docs-6.8' of git://git.lwn.net/linux

2024-01-12T03:46:52Z

Pull documentation update from Jonathan Corbet: "Another moderately busy cycle for documentation, including: - The minimum Sphinx requirement has been raised to 2.4.4, following a warning that was added in 6.2 - Some reworking of the Documentation/process front page to, hopefully, make it more useful - Various kernel-doc tweaks to, for example, make it deal properly with __counted_by annotations - We have also restored a warning for documentation of nonexistent structure members that disappeared a while back. That had the delightful consequence of adding some 600 warnings to the docs build. A sustained effort by Randy, Vegard, and myself has addressed almost all of those, bringing the documentation back into sync with the code. The fixes are going through the appropriate maintainer trees - Various improvements to the HTML rendered docs, including automatic links to Git revisions and a nice new pulldown to make translations easy to access - Speaking of translations, more of those for Spanish and Chinese ... plus the usual stream of documentation updates and typo fixes" * tag 'docs-6.8' of git://git.lwn.net/linux: (57 commits) MAINTAINERS: use tabs for indent of CONFIDENTIAL COMPUTING THREAT MODEL A reworked process/index.rst ring-buffer/Documentation: Add documentation on buffer_percent file Translated the RISC-V architecture boot documentation. Docs: remove mentions of fdformat from util-linux Docs/zh_CN: Fix the meaning of DEBUG to pr_debug() Documentation: move driver-api/dcdbas to userspace-api/ Documentation: move driver-api/isapnp to userspace-api/ Documentation/core-api : fix typo in workqueue Documentation/trace: Fixed typos in the ftrace FLAGS section kernel-doc: handle a void function without producing a warning scripts/get_abi.pl: ignore some temp files docs: kernel_abi.py: fix command injection scripts/get_abi: fix source path leak CREDITS, MAINTAINERS, docs/process/howto: Update man-pages' maintainer docs: translations: add translations links when they exist kernel-doc: Align quick help and the code MAINTAINERS: add reviewer for Spanish translations docs: ignore __counted_by attribute in structure definitions scripts: kernel-doc: Clarify missing struct member description ..

Merge tag 'v6.8-p1' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6

2024-01-10T20:23:43Z

Pull crypto updates from Herbert Xu: "API: - Add incremental lskcipher/skcipher processing Algorithms: - Remove SHA1 from drbg - Remove CFB and OFB Drivers: - Add comp high perf mode configuration in hisilicon/zip - Add support for 420xx devices in qat - Add IAA Compression Accelerator driver" * tag 'v6.8-p1' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (172 commits) crypto: iaa - Account for cpu-less numa nodes crypto: scomp - fix req->dst buffer overflow crypto: sahara - add support for crypto_engine crypto: sahara - remove error message for bad aes request size crypto: sahara - remove unnecessary NULL assignments crypto: sahara - remove 'active' flag from sahara_aes_reqctx struct crypto: sahara - use dev_err_probe() crypto: sahara - use devm_clk_get_enabled() crypto: sahara - use BIT() macro crypto: sahara - clean up macro indentation crypto: sahara - do not resize req->src when doing hash operations crypto: sahara - fix processing hash requests with req->nbytes < sg->length crypto: sahara - improve error handling in sahara_sha_process() crypto: sahara - fix wait_for_completion_timeout() error handling crypto: sahara - fix ahash reqsize crypto: sahara - handle zero-length aes requests crypto: skcipher - remove excess kerneldoc members crypto: shash - remove excess kerneldoc members crypto: qat - generate dynamically arbiter mappings crypto: qat - add support for ring pair level telemetry ...

Documentation: move driver-api/dcdbas to userspace-api/

2024-01-03T21:17:40Z

This file documents a sysfs interface that is intended for systems management software. It does NOT document any kind of kernel driver API. It is also not meant to be used directly by system administrators or users. Cc: Stuart Hayes Cc: platform-driver-x86@vger.kernel.org Signed-off-by: Vegard Nossum Acked-by: Hans de Goede Reviewed-by: Randy Dunlap Signed-off-by: Jonathan Corbet Link: https://lore.kernel.org/r/20231221124816.2978000-3-vegard.nossum@oracle.com