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2025-03-29Merge tag 'for-linus-fwctl' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma Pull fwctl subsystem from Jason Gunthorpe: "fwctl is a new subsystem intended to bring some common rules and order to the growing pattern of exposing a secure FW interface directly to userspace. Unlike existing places like RDMA/DRM/VFIO/uacce that are exposing a device for datapath operations fwctl is focused on debugging, configuration and provisioning of the device. It will not have the necessary features like interrupt delivery to support a datapath. This concept is similar to the long standing practice in the "HW" RAID space of having a device specific misc device to manage the RAID controller FW. fwctl generalizes this notion of a companion debug and management interface that goes along with a dataplane implemented in an appropriate subsystem. There have been three LWN articles written discussing various aspects of this: https://lwn.net/Articles/955001/ https://lwn.net/Articles/969383/ https://lwn.net/Articles/990802/ This includes three drivers to launch the subsystem: - CXL provides a vendor scheme for executing commands and a way to learn the 'command effects' (ie the security properties) of such commands. The fwctl driver allows access to these mechanism within the fwctl security model - mlx5 is family of networking products, the driver supports all current Mellanox HW still receiving FW feature updates. This includes RDMA multiprotocol NICs like ConnectX and the Bluefield family of Smart NICs. - AMD/Pensando Distributed Services card is a multi protocol Smart NIC with a multi PCI function design. fwctl works on the management PCI function following a 'command effects' model similar to CXL" * tag 'for-linus-fwctl' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma: (30 commits) pds_fwctl: add Documentation entries pds_fwctl: add rpc and query support pds_fwctl: initial driver framework pds_core: add new fwctl auxiliary_device pds_core: specify auxiliary_device to be created pds_core: make pdsc_auxbus_dev_del() void cxl: Fixup kdoc issues for include/cxl/features.h fwctl/cxl: Add documentation to FWCTL CXL cxl/test: Add Set Feature support to cxl_test cxl/test: Add Get Feature support to cxl_test cxl: Add support to handle user feature commands for set feature cxl: Add support to handle user feature commands for get feature cxl: Add support for fwctl RPC command to enable CXL feature commands cxl: Move cxl feature command structs to user header cxl: Add FWCTL support to CXL mlx5: Create an auxiliary device for fwctl_mlx5 fwctl/mlx5: Support for communicating with mlx5 fw fwctl: Add documentation fwctl: FWCTL_RPC to execute a Remote Procedure Call to device firmware taint: Add TAINT_FWCTL ...
2025-03-12Documentation: dma-buf: heaps: Add heap name definitionsMaxime Ripard
Following a recent discussion at last Plumbers, John Stultz, Sumit Sewal, TJ Mercier and I came to an agreement that we should document what the dma-buf heaps names are expected to be, and what the buffers attributes you'll get should be documented. Let's create that doc to make sure those attributes and names are guaranteed going forward. Reviewed-by: T.J. Mercier <tjmercier@google.com> Signed-off-by: Maxime Ripard <mripard@kernel.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Link: https://lore.kernel.org/r/20250306135114.1943738-1-mripard@kernel.org
2025-03-06fwctl: Add documentationJason Gunthorpe
Document the purpose and rules for the fwctl subsystem. Link in kdocs to the doc tree. Link: https://patch.msgid.link/r/6-v5-642aa0c94070+4447f-fwctl_jgg@nvidia.com Nacked-by: Jakub Kicinski <kuba@kernel.org> Link: https://lore.kernel.org/r/20240603114250.5325279c@kernel.org Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://lore.kernel.org/r/ZrHY2Bds7oF7KRGz@phenom.ffwll.local Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Reviewed-by: Shannon Nelson <shannon.nelson@amd.com> Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
2025-01-27Merge tag 'char-misc-6.14-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc Pull Char/Misc/IIO driver updates from Greg KH: "Here is the "big" set of char/misc/iio and other smaller driver subsystem updates for 6.14-rc1. Loads of different things in here this development cycle, highlights are: - ntsync "driver" to handle Windows locking types enabling Wine to work much better on many workloads (i.e. games). The driver framework was in 6.13, but now it's enabled and fully working properly. Should make many SteamOS users happy. Even comes with tests! - Large IIO driver updates and bugfixes - FPGA driver updates - Coresight driver updates - MHI driver updates - PPS driver updatesa - const bin_attribute reworking for many drivers - binder driver updates - smaller driver updates and fixes All of these have been in linux-next for a while with no reported issues" * tag 'char-misc-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (311 commits) ntsync: Fix reference leaks in the remaining create ioctls. spmi: hisi-spmi-controller: Drop duplicated OF node assignment in spmi_controller_probe() spmi: Set fwnode for spmi devices ntsync: fix a file reference leak in drivers/misc/ntsync.c scripts/tags.sh: Don't tag usages of DECLARE_BITMAP dt-bindings: interconnect: qcom,msm8998-bwmon: Add SM8750 CPU BWMONs dt-bindings: interconnect: OSM L3: Document sm8650 OSM L3 compatible dt-bindings: interconnect: qcom-bwmon: Document QCS615 bwmon compatibles interconnect: sm8750: Add missing const to static qcom_icc_desc memstick: core: fix kernel-doc notation intel_th: core: fix kernel-doc warnings binder: log transaction code on failure iio: dac: ad3552r-hs: clear reset status flag iio: dac: ad3552r-common: fix ad3541/2r ranges iio: chemical: bme680: Fix uninitialized variable in __bme680_read_raw() misc: fastrpc: Fix copy buffer page size misc: fastrpc: Fix registered buffer page address misc: fastrpc: Deregister device nodes properly in error scenarios nvmem: core: improve range check for nvmem_cell_write() nvmem: qcom-spmi-sdam: Set size in struct nvmem_config ...
2025-01-08docs: ntsync: Add documentation for the ntsync uAPI.Elizabeth Figura
Add an overall explanation of the driver architecture, and complete and precise specification for its intended behaviour. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20241213193511.457338-30-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-18exec: Add a new AT_EXECVE_CHECK flag to execveat(2)Mickaël Salaün
Add a new AT_EXECVE_CHECK flag to execveat(2) to check if a file would be allowed for execution. The main use case is for script interpreters and dynamic linkers to check execution permission according to the kernel's security policy. Another use case is to add context to access logs e.g., which script (instead of interpreter) accessed a file. As any executable code, scripts could also use this check [1]. This is different from faccessat(2) + X_OK which only checks a subset of access rights (i.e. inode permission and mount options for regular files), but not the full context (e.g. all LSM access checks). The main use case for access(2) is for SUID processes to (partially) check access on behalf of their caller. The main use case for execveat(2) + AT_EXECVE_CHECK is to check if a script execution would be allowed, according to all the different restrictions in place. Because the use of AT_EXECVE_CHECK follows the exact kernel semantic as for a real execution, user space gets the same error codes. An interesting point of using execveat(2) instead of openat2(2) is that it decouples the check from the enforcement. Indeed, the security check can be logged (e.g. with audit) without blocking an execution environment not yet ready to enforce a strict security policy. LSMs can control or log execution requests with security_bprm_creds_for_exec(). However, to enforce a consistent and complete access control (e.g. on binary's dependencies) LSMs should restrict file executability, or measure executed files, with security_file_open() by checking file->f_flags & __FMODE_EXEC. Because AT_EXECVE_CHECK is dedicated to user space interpreters, it doesn't make sense for the kernel to parse the checked files, look for interpreters known to the kernel (e.g. ELF, shebang), and return ENOEXEC if the format is unknown. Because of that, security_bprm_check() is never called when AT_EXECVE_CHECK is used. It should be noted that script interpreters cannot directly use execveat(2) (without this new AT_EXECVE_CHECK flag) because this could lead to unexpected behaviors e.g., `python script.sh` could lead to Bash being executed to interpret the script. Unlike the kernel, script interpreters may just interpret the shebang as a simple comment, which should not change for backward compatibility reasons. Because scripts or libraries files might not currently have the executable permission set, or because we might want specific users to be allowed to run arbitrary scripts, the following patch provides a dynamic configuration mechanism with the SECBIT_EXEC_RESTRICT_FILE and SECBIT_EXEC_DENY_INTERACTIVE securebits. This is a redesign of the CLIP OS 4's O_MAYEXEC: https://github.com/clipos-archive/src_platform_clip-patches/blob/f5cb330d6b684752e403b4e41b39f7004d88e561/1901_open_mayexec.patch This patch has been used for more than a decade with customized script interpreters. Some examples can be found here: https://github.com/clipos-archive/clipos4_portage-overlay/search?q=O_MAYEXEC Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Kees Cook <keescook@chromium.org> Acked-by: Paul Moore <paul@paul-moore.com> Reviewed-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Jeff Xu <jeffxu@chromium.org> Tested-by: Jeff Xu <jeffxu@chromium.org> Link: https://docs.python.org/3/library/io.html#io.open_code [1] Signed-off-by: Mickaël Salaün <mic@digikod.net> Link: https://lore.kernel.org/r/20241212174223.389435-2-mic@digikod.net Signed-off-by: Kees Cook <kees@kernel.org>
2024-07-19Merge tag 'iommu-updates-v6.11' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/iommu/linux Pull iommu updates from Will Deacon: "Core: - Support for the "ats-supported" device-tree property - Removal of the 'ops' field from 'struct iommu_fwspec' - Introduction of iommu_paging_domain_alloc() and partial conversion of existing users - Introduce 'struct iommu_attach_handle' and provide corresponding IOMMU interfaces which will be used by the IOMMUFD subsystem - Remove stale documentation - Add missing MODULE_DESCRIPTION() macro - Misc cleanups Allwinner Sun50i: - Ensure bypass mode is disabled on H616 SoCs - Ensure page-tables are allocated below 4GiB for the 32-bit page-table walker - Add new device-tree compatible strings AMD Vi: - Use try_cmpxchg64() instead of cmpxchg64() when updating pte Arm SMMUv2: - Print much more useful information on context faults - Fix Qualcomm TBU probing when CONFIG_ARM_SMMU_QCOM_DEBUG=n - Add new Qualcomm device-tree bindings Arm SMMUv3: - Support for hardware update of access/dirty bits and reporting via IOMMUFD - More driver rework from Jason, this time updating the PASID/SVA support to prepare for full IOMMUFD support - Add missing MODULE_DESCRIPTION() macro - Minor fixes and cleanups NVIDIA Tegra: - Fix for benign fwspec initialisation issue exposed by rework on the core branch Intel VT-d: - Use try_cmpxchg64() instead of cmpxchg64() when updating pte - Use READ_ONCE() to read volatile descriptor status - Remove support for handling Execute-Requested requests - Avoid calling iommu_domain_alloc() - Minor fixes and refactoring Qualcomm MSM: - Updates to the device-tree bindings" * tag 'iommu-updates-v6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/iommu/linux: (72 commits) iommu/tegra-smmu: Pass correct fwnode to iommu_fwspec_init() iommu/vt-d: Fix identity map bounds in si_domain_init() iommu: Move IOMMU_DIRTY_NO_CLEAR define dt-bindings: iommu: Convert msm,iommu-v0 to yaml iommu/vt-d: Fix aligned pages in calculate_psi_aligned_address() iommu/vt-d: Limit max address mask to MAX_AGAW_PFN_WIDTH docs: iommu: Remove outdated Documentation/userspace-api/iommu.rst arm64: dts: fvp: Enable PCIe ATS for Base RevC FVP iommu/of: Support ats-supported device-tree property dt-bindings: PCI: generic: Add ats-supported property iommu: Remove iommu_fwspec ops OF: Simplify of_iommu_configure() ACPI: Retire acpi_iommu_fwspec_ops() iommu: Resolve fwspec ops automatically iommu/mediatek-v1: Clean up redundant fwspec checks RDMA/usnic: Use iommu_paging_domain_alloc() wifi: ath11k: Use iommu_paging_domain_alloc() wifi: ath10k: Use iommu_paging_domain_alloc() drm/msm: Use iommu_paging_domain_alloc() vhost-vdpa: Use iommu_paging_domain_alloc() ...
2024-07-09docs: iommu: Remove outdated Documentation/userspace-api/iommu.rstMark-PK Tsai
The Documentation/userspace-api/iommu.rst file has become outdated due to the removal of associated structures and APIs. Specifically, struct such as iommu_cache_invalidate_info and guest pasid related uapi were removed in commit 0c9f17877891 ("iommu: Remove guest pasid related interfaces and definitions"). And the corresponding uapi/linux/iommu.h file was removed in commit 00a9bc607043 ("iommu: Move iommu fault data to linux/iommu.h"). Signed-off-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com> Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Link: https://lore.kernel.org/r/20240702120617.26882-1-mark-pk.tsai@mediatek.com [will: Remove stale reference to 'iommu' from index.rst] Signed-off-by: Will Deacon <will@kernel.org>
2024-06-15mm/memfd: add documentation for MFD_NOEXEC_SEAL MFD_EXECJeff Xu
When MFD_NOEXEC_SEAL was introduced, there was one big mistake: it didn't have proper documentation. This led to a lot of confusion, especially about whether or not memfd created with the MFD_NOEXEC_SEAL flag is sealable. Before MFD_NOEXEC_SEAL, memfd had to explicitly set MFD_ALLOW_SEALING to be sealable, so it's a fair question. As one might have noticed, unlike other flags in memfd_create, MFD_NOEXEC_SEAL is actually a combination of multiple flags. The idea is to make it easier to use memfd in the most common way, which is NOEXEC + F_SEAL_EXEC + MFD_ALLOW_SEALING. This works with sysctl vm.noexec to help existing applications move to a more secure way of using memfd. Proposals have been made to put MFD_NOEXEC_SEAL non-sealable, unless MFD_ALLOW_SEALING is set, to be consistent with other flags [1], Those are based on the viewpoint that each flag is an atomic unit, which is a reasonable assumption. However, MFD_NOEXEC_SEAL was designed with the intent of promoting the most secure method of using memfd, therefore a combination of multiple functionalities into one bit. Furthermore, the MFD_NOEXEC_SEAL has been added for more than one year, and multiple applications and distributions have backported and utilized it. Altering ABI now presents a degree of risk and may lead to disruption. MFD_NOEXEC_SEAL is a new flag, and applications must change their code to use it. There is no backward compatibility problem. When sysctl vm.noexec == 1 or 2, applications that don't set MFD_NOEXEC_SEAL or MFD_EXEC will get MFD_NOEXEC_SEAL memfd. And old-application might break, that is by-design, in such a system vm.noexec = 0 shall be used. Also no backward compatibility problem. I propose to include this documentation patch to assist in clarifying the semantics of MFD_NOEXEC_SEAL, thereby preventing any potential future confusion. Finally, I would like to express my gratitude to David Rheinsberg and Barnabás Pőcze for initiating the discussion on the topic of sealability. [1] https://lore.kernel.org/lkml/20230714114753.170814-1-david@readahead.eu/ [jeffxu@chromium.org: updates per Randy] Link: https://lkml.kernel.org/r/20240611034903.3456796-2-jeffxu@chromium.org [jeffxu@chromium.org: v3] Link: https://lkml.kernel.org/r/20240611231409.3899809-2-jeffxu@chromium.org Link: https://lkml.kernel.org/r/20240607203543.2151433-2-jeffxu@google.com Signed-off-by: Jeff Xu <jeffxu@chromium.org> Reviewed-by: Randy Dunlap <rdunlap@infradead.org> Cc: Aleksa Sarai <cyphar@cyphar.com> Cc: Barnabás Pőcze <pobrn@protonmail.com> Cc: Daniel Verkamp <dverkamp@chromium.org> Cc: David Rheinsberg <david@readahead.eu> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jorge Lucangeli Obes <jorgelo@chromium.org> Cc: Kees Cook <keescook@chromium.org> Cc: Shuah Khan <skhan@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-05-23mseal: add documentationJeff Xu
Add documentation for mseal(). Link: https://lkml.kernel.org/r/20240415163527.626541-5-jeffxu@chromium.org Signed-off-by: Jeff Xu <jeffxu@chromium.org> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Guenter Roeck <groeck@chromium.org> Cc: Jann Horn <jannh@google.com> Cc: Jeff Xu <jeffxu@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jorge Lucangeli Obes <jorgelo@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Muhammad Usama Anjum <usama.anjum@collabora.com> Cc: Pedro Falcato <pedro.falcato@gmail.com> Cc: Stephen Röttger <sroettger@google.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Amer Al Shanawany <amer.shanawany@gmail.com> Cc: Javier Carrasco <javier.carrasco.cruz@gmail.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-03-13Merge tag 'gpio-updates-for-v6.9-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux Pull gpio updates from Bartosz Golaszewski: "The biggest feature is the locking overhaul. Up until now the synchronization in the GPIO subsystem was broken. There was a single spinlock "protecting" multiple data structures but doing it wrong (as evidenced by several places where it would be released when a sleeping function was called and then reacquired without checking the protected state). We tried to use an RW semaphore before but the main issue with GPIO is that we have drivers implementing the interfaces in both sleeping and non-sleeping ways as well as user-facing interfaces that can be called both from process as well as atomic contexts. Both ends converge in the same code paths that can use neither spinlocks nor mutexes. The only reasonable way out is to use SRCU and go mostly lockless. To that end: we add several SRCU structs in relevant places and use them to assure consistency between API calls together with atomic reads and writes of GPIO descriptor flags where it makes sense. This code has spent several weeks in next and has received several fixes in the first week or two after which it stabilized nicely. The GPIO subsystem is now resilient to providers being suddenly unbound. We managed to also remove the existing character device RW semaphore and the obsolete global spinlock. Other than the locking rework we have one new driver (for Chromebook EC), much appreciated documentation improvements from Kent and the regular driver improvements, DT-bindings updates and GPIOLIB core tweaks. Serialization rework: - use SRCU to serialize access to the global GPIO device list, to GPIO device structs themselves and to GPIO descriptors - make the GPIO subsystem resilient to the GPIO providers being unbound while the API calls are in progress - don't dereference the SRCU-protected chip pointer if the information we need can be obtained from the GPIO device structure - move some of the information contained in struct gpio_chip to struct gpio_device to further reduce the need to dereference the former - pass the GPIO device struct instead of the GPIO chip to sysfs callback to, again, reduce the need for accessing the latter - get GPIO descriptors from the GPIO device, not from the chip for the same reason - allow for mostly lockless operation of the GPIO driver API: assure consistency with SRCU and atomic operations - remove the global GPIO spinlock - remove the character device RW semaphore Core GPIOLIB: - constify pointers in GPIO API where applicable - unify the GPIO counting APIs for ACPI and OF - provide a macro for iterating over all GPIOs, not only the ones that are requested - remove leftover typedefs - pass the consumer device to GPIO core in devm_fwnode_gpiod_get_index() for improved logging - constify the GPIO bus type - don't warn about removing GPIO chips with descriptors still held by users as we can now handle this situation gracefully - remove unused logging helpers - unexport functions that are only used internally in the GPIO subsystem - set the device type (assign the relevant struct device_type) for GPIO devices New drivers: - add the ChromeOS EC GPIO driver Driver improvements: - allow building gpio-vf610 with COMPILE_TEST as well as disabling it in menuconfig (before it was always built for i.MX cofigs) - count the number of EICs using the device properties instead of hard-coding it in gpio-eic-sprd - improve the device naming, extend the debugfs output and add lockdep asserts to gpio-sim DT bindings: - document the 'label' property for gpio-pca9570 - convert aspeed,ast2400-gpio bindings to DT schema - disallow unevaluated properties for gpio-mvebu - document a new model in renesas,rcar-gpio Documentation: - improve the character device kerneldocs in user-space headers - add proper documentation for the character device uAPI (both v1 and v2) - move the sysfs and gpio-mockup docs into the "obsolete" section - improve naming consistency for GPIO terms - clarify the line values description for sysfs - minor docs improvements - improve the driver API contract for setting GPIO direction - mark unsafe APIs as deprecated in kerneldocs and suggest replacements Other: - remove an obsolete test from selftests" * tag 'gpio-updates-for-v6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux: (79 commits) gpio: sysfs: repair export returning -EPERM on 1st attempt selftest: gpio: remove obsolete gpio-mockup test gpiolib: Deduplicate cleanup for-loop in gpiochip_add_data_with_key() dt-bindings: gpio: aspeed,ast2400-gpio: Convert to DT schema gpio: acpi: Make acpi_gpio_count() take firmware node as a parameter gpio: of: Make of_gpio_get_count() take firmware node as a parameter gpiolib: Pass consumer device through to core in devm_fwnode_gpiod_get_index() gpio: sim: use for_each_hwgpio() gpio: provide for_each_hwgpio() gpio: don't warn about removing GPIO chips with active users anymore gpio: sim: delimit the fwnode name with a ":" when generating labels gpio: sim: add lockdep asserts gpio: Add ChromeOS EC GPIO driver gpio: constify of_phandle_args in of_find_gpio_device_by_xlate() gpio: fix memory leak in gpiod_request_commit() gpio: constify opaque pointer "data" in gpio_device_find() gpio: cdev: fix a NULL-pointer dereference with DEBUG enabled gpio: uapi: clarify default_values being logical gpio: sysfs: fix inverted pointer logic gpio: don't let lockdep complain about inherently dangerous RCU usage ...
2024-01-30Documentation: userspace-api: Document perf ring buffer mechanismLeo Yan
In the Linux perf tool, the ring buffer serves not only as a medium for transferring PMU event data but also as a vital mechanism for hardware tracing using technologies like Intel PT and Arm CoreSight, etc. Consequently, the ring buffer mechanism plays a crucial role by ensuring high throughput for data transfer between the kernel and user space while avoiding excessive overhead caused by the ring buffer itself. This commit documents the ring buffer mechanism in detail. It explains the implementation of both the regular ring buffer and the AUX ring buffer. Additionally, it covers how these ring buffers support various tracing modes and explains the synchronization with memory barriers. Signed-off-by: Leo Yan <leo.yan@linaro.org> Reviewed-by: James Clark <james.clark@arm.com> Reviewed-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Link: https://lore.kernel.org/r/20240102085001.228815-1-leo.yan@linaro.org
2024-01-30docs: rework the userspace-api top pageJonathan Corbet
Add some subsection headings and reorder entries so that the page makes a bit more sense. With luck, adding some ordering will also reduce merge conflicts due to everybody adding new entries at the end. Signed-off-by: Jonathan Corbet <corbet@lwn.net> Link: https://lore.kernel.org/r/87ttn5m2q1.fsf@meer.lwn.net
2024-01-22Documentation: gpio: add chardev userspace API documentationKent Gibson
Add documentation for the GPIO character device userspace API. Added to the userspace-api book, but also provide a link from the admin-guide book, as historically the GPIO documentation has been there. Signed-off-by: Kent Gibson <warthog618@gmail.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
2024-01-11Merge tag 'docs-6.8' of git://git.lwn.net/linuxLinus Torvalds
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 ..
2024-01-03Documentation: move driver-api/dcdbas to userspace-api/Vegard Nossum
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 <stuart.w.hayes@gmail.com> Cc: platform-driver-x86@vger.kernel.org Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> Acked-by: Hans de Goede <hdegoede@redhat.com> Reviewed-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Link: https://lore.kernel.org/r/20231221124816.2978000-3-vegard.nossum@oracle.com
2024-01-03Documentation: move driver-api/isapnp to userspace-api/Vegard Nossum
driver-api/isapnp documents /proc interfaces for interfacing directly with ISA Plug & Play devices, not any kind of API for kernel developers, and should thus also live under userspace-api/. Also fix a few issues while we're at it. Cc: Jaroslav Kysela <perex@perex.cz> Cc: Mauro Carvalho Chehab <mchehab@kernel.org> Cc: Alexandre Belloni <alexandre.belloni@bootlin.com> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> Reviewed-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Link: https://lore.kernel.org/r/20231221124816.2978000-2-vegard.nossum@oracle.com
2023-12-08Documentation: Destage TEE subsystem documentationSumit Garg
Add a separate documentation directory for TEE subsystem since it is a standalone subsystem which already offers devices consumed by multiple different subsystem drivers. Split overall TEE subsystem documentation modularly where: - The userspace API has been moved to Documentation/userspace-api/tee.rst. - The driver API has been moved to Documentation/driver-api/tee.rst. - The first module covers the overview of TEE subsystem. - The further modules are dedicated to different TEE implementations like: - OP-TEE - AMD-TEE - and so on for future TEE implementation support. Acked-by: Rijo Thomas <Rijo-john.Thomas@amd.com> Acked-by: Jens Wiklander <jens.wiklander@linaro.org> Signed-off-by: Sumit Garg <sumit.garg@linaro.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Link: https://lore.kernel.org/r/20231128072352.866859-1-sumit.garg@linaro.org
2023-11-17Merge branch 'vegard' into docs-mwJonathan Corbet
Vegard Nossum writes: This patch series replaces some instances of 'class:: toc-title' with toctree's :caption: attribute, see the last patch in the series for some more rationale/explanation.
2023-11-17doc: userspace-api: properly format ToC headingsVegard Nossum
"class:: toc-title" was a workaround for older Sphinx versions that are no longer supported. The canonical way to add a heading to the ToC is to use :caption:. Do that. Cc: Rui Li <me@lirui.org> Cc: Yanteng Si <siyanteng@loongson.cn> Cc: Wu XiangCheng <bobwxc@email.cn> Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Link: https://lore.kernel.org/r/20231027081830.195056-3-vegard.nossum@oracle.com
2023-11-12LSM: Identify modules by more than nameCasey Schaufler
Create a struct lsm_id to contain identifying information about Linux Security Modules (LSMs). At inception this contains the name of the module and an identifier associated with the security module. Change the security_add_hooks() interface to use this structure. Change the individual modules to maintain their own struct lsm_id and pass it to security_add_hooks(). The values are for LSM identifiers are defined in a new UAPI header file linux/lsm.h. Each existing LSM has been updated to include it's LSMID in the lsm_id. The LSM ID values are sequential, with the oldest module LSM_ID_CAPABILITY being the lowest value and the existing modules numbered in the order they were included in the main line kernel. This is an arbitrary convention for assigning the values, but none better presents itself. The value 0 is defined as being invalid. The values 1-99 are reserved for any special case uses which may arise in the future. This may include attributes of the LSM infrastructure itself, possibly related to namespacing or network attribute management. A special range is identified for such attributes to help reduce confusion for developers unfamiliar with LSMs. LSM attribute values are defined for the attributes presented by modules that are available today. As with the LSM IDs, The value 0 is defined as being invalid. The values 1-99 are reserved for any special case uses which may arise in the future. Cc: linux-security-module <linux-security-module@vger.kernel.org> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Mickael Salaun <mic@digikod.net> Reviewed-by: John Johansen <john.johansen@canonical.com> Signed-off-by: Kees Cook <keescook@chromium.org> Nacked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> [PM: forward ported beyond v6.6 due merge window changes] Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-08-21doc: uapi: Add document describing dma-buf semanticsDaniel Stone
Since there's a lot of confusion around this, document both the rules and the best practices around negotiating, allocating, importing, and using buffers when crossing context/process/device/subsystem boundaries. This ties up all of dma-buf, formats and modifiers, and their usage. Signed-off-by: Daniel Stone <daniels@collabora.com> Signed-off-by: Simon Ser <contact@emersion.fr> Reviewed-by: Simon Ser <contact@emersion.fr> Reviewed-by: Sui Jingfeng <suijingfeng@loongson.cn> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20230803154908.105124-4-daniels@collabora.com
2023-04-20ELF: document some de-facto PT_* ABI quirksAlexey Dobriyan
Turns out rules about PT_INTERP, PT_GNU_STACK and PT_GNU_PROPERTY program headers are slightly different. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Link: https://lore.kernel.org/r/88d3f1bb-f4e0-4c40-9304-3843513a1262@p183 Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2022-11-30iommufd: Document overview of iommufdKevin Tian
Add iommufd into the documentation tree, and supply initial documentation. Much of this is linked from code comments by kdoc. Link: https://lore.kernel.org/r/5-v6-a196d26f289e+11787-iommufd_jgg@nvidia.com Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Signed-off-by: Kevin Tian <kevin.tian@intel.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
2022-08-23docs: netlink: basic introduction to NetlinkJakub Kicinski
Provide a bit of a brain dump of netlink related information as documentation. Hopefully this will be useful to people trying to navigate implementing YAML based parsing in languages we won't be able to help with. I started writing this doc while trying to figure out what it'd take to widen the applicability of YAML to good old rtnl, but the doc grew beyond that as it usually happens. In all honesty a lot of this information is new to me as I usually follow the "copy an existing example, drink to forget" process of writing netlink user space, so reviews will be much appreciated. Reviewed-by: Jacob Keller <jacob.e.keller@intel.com> Acked-by: Jonathan Corbet <corbet@lwn.net> Link: https://lore.kernel.org/r/20220819200221.422801-2-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-10-07futex2: Documentation: Document sys_futex_waitv() uAPIAndré Almeida
Create userspace documentation for futex_waitv() syscall, detailing how the arguments are used. Signed-off-by: André Almeida <andrealmeid@collabora.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20210923171111.300673-23-andrealmeid@collabora.com
2021-09-06Documentation: Add documentation for VDUSEXie Yongji
VDUSE (vDPA Device in Userspace) is a framework to support implementing software-emulated vDPA devices in userspace. This document is intended to clarify the VDUSE design and usage. Signed-off-by: Xie Yongji <xieyongji@bytedance.com> Acked-by: Jason Wang <jasowang@redhat.com> Link: https://lore.kernel.org/r/20210831103634.33-14-xieyongji@bytedance.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2021-05-01Merge tag 'landlock_v34' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security Pull Landlock LSM from James Morris: "Add Landlock, a new LSM from Mickaël Salaün. Briefly, Landlock provides for unprivileged application sandboxing. From Mickaël's cover letter: "The goal of Landlock is to enable to restrict ambient rights (e.g. global filesystem access) for a set of processes. Because Landlock is a stackable LSM [1], it makes possible to create safe security sandboxes as new security layers in addition to the existing system-wide access-controls. This kind of sandbox is expected to help mitigate the security impact of bugs or unexpected/malicious behaviors in user-space applications. Landlock empowers any process, including unprivileged ones, to securely restrict themselves. Landlock is inspired by seccomp-bpf but instead of filtering syscalls and their raw arguments, a Landlock rule can restrict the use of kernel objects like file hierarchies, according to the kernel semantic. Landlock also takes inspiration from other OS sandbox mechanisms: XNU Sandbox, FreeBSD Capsicum or OpenBSD Pledge/Unveil. In this current form, Landlock misses some access-control features. This enables to minimize this patch series and ease review. This series still addresses multiple use cases, especially with the combined use of seccomp-bpf: applications with built-in sandboxing, init systems, security sandbox tools and security-oriented APIs [2]" The cover letter and v34 posting is here: https://lore.kernel.org/linux-security-module/20210422154123.13086-1-mic@digikod.net/ See also: https://landlock.io/ This code has had extensive design discussion and review over several years" Link: https://lore.kernel.org/lkml/50db058a-7dde-441b-a7f9-f6837fe8b69f@schaufler-ca.com/ [1] Link: https://lore.kernel.org/lkml/f646e1c7-33cf-333f-070c-0a40ad0468cd@digikod.net/ [2] * tag 'landlock_v34' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: landlock: Enable user space to infer supported features landlock: Add user and kernel documentation samples/landlock: Add a sandbox manager example selftests/landlock: Add user space tests landlock: Add syscall implementations arch: Wire up Landlock syscalls fs,security: Add sb_delete hook landlock: Support filesystem access-control LSM: Infrastructure management of the superblock landlock: Add ptrace restrictions landlock: Set up the security framework and manage credentials landlock: Add ruleset and domain management landlock: Add object management
2021-04-22landlock: Add user and kernel documentationMickaël Salaün
Add a first document describing userspace API: how to define and enforce a Landlock security policy. This is explained with a simple example. The Landlock system calls are described with their expected behavior and current limitations. Another document is dedicated to kernel developers, describing guiding principles and some important kernel structures. This documentation can be built with the Sphinx framework. Cc: James Morris <jmorris@namei.org> Cc: Jann Horn <jannh@google.com> Cc: Serge E. Hallyn <serge@hallyn.com> Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com> Reviewed-by: Vincent Dagonneau <vincent.dagonneau@ssi.gouv.fr> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20210422154123.13086-13-mic@digikod.net Signed-off-by: James Morris <jamorris@linux.microsoft.com>
2021-03-04docs/bpf: Add bpf() syscall command referenceJoe Stringer
Generate the syscall command reference from the UAPI header file and include it in the main bpf docs page. Signed-off-by: Joe Stringer <joe@cilium.io> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Quentin Monnet <quentin@isovalent.com> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/bpf/20210302171947.2268128-15-joe@cilium.io
2020-12-30Documentation: Add documentation for new platform_profile sysfs attributeMark Pearson
On modern systems the platform performance, temperature, fan and other hardware related characteristics are often dynamically configurable. The profile is often automatically adjusted to the load by some automatic-mechanism (which may very well live outside the kernel). These auto platform-adjustment mechanisms often can be configured with one of several 'platform-profiles', with either a bias towards low-power consumption or towards performance (and higher power consumption and thermals). Introduce a new platform_profile sysfs API which offers a generic API for selecting the performance-profile of these automatic-mechanisms. Co-developed-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Mark Pearson <markpearson@lenovo.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-10-28docs: userspace-api: add iommu.rst to the index fileMauro Carvalho Chehab
There's a new uAPI doc for IOMMU. Add it to the index file. Should address this warning: .../Documentation/userspace-api/iommu.rst: WARNING: document isn't included in any toctree Fixes: d0023e3ee28d ("docs: IOMMU user API") Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/cc55219a551e29848e2282cd8939a4115067234c.1603791716.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-14media: docs: get rid of Documentation/media/Mauro Carvalho Chehab
Now that everything got moved, we can get rid of the old media directory. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2019-10-10docs: Move the user-space ioctl() docs to userspace-apiJonathan Corbet
This is strictly user-space material at this point, so put it with the other user-space API documentation. Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2019-07-15docs: ocxl.rst: add it to the uAPI bookMauro Carvalho Chehab
The content of this file is user-faced. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Acked-by: Andrew Donnellan <ajd@linux.ibm.com>
2018-05-03prctl: Add speculation control prctlsThomas Gleixner
Add two new prctls to control aspects of speculation related vulnerabilites and their mitigations to provide finer grained control over performance impacting mitigations. PR_GET_SPECULATION_CTRL returns the state of the speculation misfeature which is selected with arg2 of prctl(2). The return value uses bit 0-2 with the following meaning: Bit Define Description 0 PR_SPEC_PRCTL Mitigation can be controlled per task by PR_SET_SPECULATION_CTRL 1 PR_SPEC_ENABLE The speculation feature is enabled, mitigation is disabled 2 PR_SPEC_DISABLE The speculation feature is disabled, mitigation is enabled If all bits are 0 the CPU is not affected by the speculation misfeature. If PR_SPEC_PRCTL is set, then the per task control of the mitigation is available. If not set, prctl(PR_SET_SPECULATION_CTRL) for the speculation misfeature will fail. PR_SET_SPECULATION_CTRL allows to control the speculation misfeature, which is selected by arg2 of prctl(2) per task. arg3 is used to hand in the control value, i.e. either PR_SPEC_ENABLE or PR_SPEC_DISABLE. The common return values are: EINVAL prctl is not implemented by the architecture or the unused prctl() arguments are not 0 ENODEV arg2 is selecting a not supported speculation misfeature PR_SET_SPECULATION_CTRL has these additional return values: ERANGE arg3 is incorrect, i.e. it's not either PR_SPEC_ENABLE or PR_SPEC_DISABLE ENXIO prctl control of the selected speculation misfeature is disabled The first supported controlable speculation misfeature is PR_SPEC_STORE_BYPASS. Add the define so this can be shared between architectures. Based on an initial patch from Tim Chen and mostly rewritten. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2017-05-18doc: ReSTify no_new_privs.txtKees Cook
This updates no_new_privs documentation to ReST markup and adds it to the user-space API documentation. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2017-05-18doc: ReSTify seccomp_filter.txtKees Cook
This updates seccomp_filter.txt for ReST markup, and moves it under the user-space API index, since it describes how application author can use seccomp. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2017-04-02docs: Convert unshare.txt to RST and add to the user-space API manualJonathan Corbet
This is a straightforward conversion, without any real textual changes. Since this document has seen no substantive changes since its addition in 2006, some such changes are probably warranted. Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2017-04-02docs: Create a user-space API guideJonathan Corbet
This is meant to be the place for documentation relevant to application developers. It's empty for the moment, but at least we have a place now! Signed-off-by: Jonathan Corbet <corbet@lwn.net>