kernel/linux.git/Documentation/userspace-api/index.rst, branch v7.0.10

Merge tag 'sched-core-2026-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2026-02-10T20:50:10+00:00

Pull scheduler updates from Ingo Molnar: "Scheduler Kconfig space updates: - Further consolidate configurable preemption modes (Peter Zijlstra) Reduce the number of architectures that are allowed to offer PREEMPT_NONE and PREEMPT_VOLUNTARY, reducing the number of preemption models from four to just two: 'full' and 'lazy' on up-to-date architectures (arm64, loongarch, powerpc, riscv, s390, x86). None and voluntary are only available as legacy features on platforms that don't implement lazy preemption yet, or which don't even support preemption. The goal is to eventually remove cond_resched() and voluntary preemption altogether. RSEQ based 'scheduler time slice extension' support (Thomas Gleixner and Peter Zijlstra): This allows a thread to request a time slice extension when it enters a critical section to avoid contention on a resource when the thread is scheduled out inside of the critical section. - Add fields and constants for time slice extension - Provide static branch for time slice extensions - Add statistics for time slice extensions - Add prctl() to enable time slice extensions - Implement sys_rseq_slice_yield() - Implement syscall entry work for time slice extensions - Implement time slice extension enforcement timer - Reset slice extension when scheduled - Implement rseq_grant_slice_extension() - entry: Hook up rseq time slice extension - selftests: Implement time slice extension test - Allow registering RSEQ with slice extension - Move slice_ext_nsec to debugfs - Lower default slice extension - selftests/rseq: Add rseq slice histogram script Scheduler performance/scalability improvements: - Update rq->avg_idle when a task is moved to an idle CPU, which improves the scalability of various workloads (Shubhang Kaushik) - Reorder fields in 'struct rq' for better caching (Blake Jones) - Fair scheduler SMP NOHZ balancing code speedups (Shrikanth Hegde): - Move checking for nohz cpus after time check - Change likelyhood of nohz.nr_cpus - Remove nohz.nr_cpus and use weight of cpumask instead - Avoid false sharing for sched_clock_irqtime (Wangyang Guo) - Cleanups (Yury Norov): - Drop useless cpumask_empty() in find_energy_efficient_cpu() - Simplify task_numa_find_cpu() - Use cpumask_weight_and() in sched_balance_find_dst_group() DL scheduler updates: - Add a deadline server for sched_ext tasks (by Andrea Righi and Joel Fernandes, with fixes by Peter Zijlstra) RT scheduler updates: - Skip currently executing CPU in rto_next_cpu() (Chen Jinghuang) Entry code updates and performance improvements (Jinjie Ruan) This is part of the scheduler tree in this cycle due to inter- dependencies with the RSEQ based time slice extension work: - Remove unused syscall argument from syscall_trace_enter() - Rework syscall_exit_to_user_mode_work() for architecture reuse - Add arch_ptrace_report_syscall_entry/exit() - Inline syscall_exit_work() and syscall_trace_enter() Scheduler core updates (Peter Zijlstra): - Rework sched_class::wakeup_preempt() and rq_modified_*() - Avoid rq->lock bouncing in sched_balance_newidle() - Rename rcu_dereference_check_sched_domain() => rcu_dereference_sched_domain() - : Add the __signed_scalar_typeof() helper Fair scheduler updates/refactoring (Peter Zijlstra and Ingo Molnar): - Fold the sched_avg update - Change rcu_dereference_check_sched_domain() to rcu-sched - Switch to rcu_dereference_all() - Remove superfluous rcu_read_lock() - Limit hrtick work - Join two #ifdef CONFIG_FAIR_GROUP_SCHED blocks - Clean up comments in 'struct cfs_rq' - Separate se->vlag from se->vprot - Rename cfs_rq::avg_load to cfs_rq::sum_weight - Rename cfs_rq::avg_vruntime to ::sum_w_vruntime & helper functions - Introduce and use the vruntime_cmp() and vruntime_op() wrappers for wrapped-signed aritmetics - Sort out 'blocked_load*' namespace noise Scheduler debugging code updates: - Export hidden tracepoints to modules (Gabriele Monaco) - Convert copy_from_user() + kstrtouint() to kstrtouint_from_user() (Fushuai Wang) - Add assertions to QUEUE_CLASS (Peter Zijlstra) - hrtimer: Fix tracing oddity (Thomas Gleixner) Misc fixes and cleanups: - Re-evaluate scheduling when migrating queued tasks out of throttled cgroups (Zicheng Qu) - Remove task_struct->faults_disabled_mapping (Christoph Hellwig) - Fix math notation errors in avg_vruntime comment (Zhan Xusheng) - sched/cpufreq: Use %pe format for PTR_ERR() printing (zenghongling)" * tag 'sched-core-2026-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (64 commits) sched: Re-evaluate scheduling when migrating queued tasks out of throttled cgroups sched/cpufreq: Use %pe format for PTR_ERR() printing sched/rt: Skip currently executing CPU in rto_next_cpu() sched/clock: Avoid false sharing for sched_clock_irqtime selftests/sched_ext: Add test for DL server total_bw consistency selftests/sched_ext: Add test for sched_ext dl_server sched/debug: Fix dl_server (re)start conditions sched/debug: Add support to change sched_ext server params sched_ext: Add a DL server for sched_ext tasks sched/debug: Stop and start server based on if it was active sched/debug: Fix updating of ppos on server write ops sched/deadline: Clear the defer params entry: Inline syscall_exit_work() and syscall_trace_enter() entry: Add arch_ptrace_report_syscall_entry/exit() entry: Rework syscall_exit_to_user_mode_work() for architecture reuse entry: Remove unused syscall argument from syscall_trace_enter() sched: remove task_struct->faults_disabled_mapping sched: Update rq->avg_idle when a task is moved to an idle CPU selftests/rseq: Add rseq slice histogram script hrtimer: Fix trace oddity ...

Documentation: use a source-read extension for the index link boilerplate

2026-01-23T18:59:34+00:00

The root document usually has a special :ref:`genindex` link to the generated index. This is also the case for Documentation/index.rst. The other index.rst files deeper in the directory hierarchy usually don't. For SPHINXDIRS builds, the root document isn't Documentation/index.rst, but some other index.rst in the hierarchy. Currently they have a ".. only::" block to add the index link when doing SPHINXDIRS html builds. This is obviously very tedious and repetitive. The link is also added to all index.rst files in the hierarchy for SPHINXDIRS builds, not just the root document. Put the boilerplate in a sphinx-includes/subproject-index.rst file, and include it at the end of the root document for subproject builds in an ad-hoc source-read extension defined in conf.py. For now, keep having the boilerplate in translations, because this approach currently doesn't cover translated index link headers. Cc: Jonathan Corbet Cc: Mauro Carvalho Chehab Cc: Randy Dunlap Signed-off-by: Jani Nikula Tested-by: Mauro Carvalho Chehab Reviewed-by: Mauro Carvalho Chehab [jc: did s/doctree/kern_doc_dir/ ] Signed-off-by: Jonathan Corbet Message-ID: <20260123143149.2024303-1-jani.nikula@intel.com>

rseq: Add fields and constants for time slice extension

2026-01-22T10:11:16+00:00

Aside of a Kconfig knob add the following items: - Two flag bits for the rseq user space ABI, which allow user space to query the availability and enablement without a syscall. - A new member to the user space ABI struct rseq, which is going to be used to communicate request and grant between kernel and user space. - A rseq state struct to hold the kernel state of this - Documentation of the new mechanism Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Link: https://patch.msgid.link/20251215155708.669472597@linutronix.de

docs: add luo documentation

2025-11-27T22:24:39+00:00

Add the documentation files for the Live Update Orchestrator Link: https://lkml.kernel.org/r/20251125165850.3389713-9-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin Reviewed-by: Mike Rapoport (Microsoft) Reviewed-by: Pratyush Yadav Tested-by: David Matlack Cc: Aleksander Lobakin Cc: Alexander Graf Cc: Alice Ryhl Cc: Andriy Shevchenko Cc: anish kumar Cc: Anna Schumaker Cc: Bartosz Golaszewski Cc: Bjorn Helgaas Cc: Borislav Betkov Cc: Chanwoo Choi Cc: Chen Ridong Cc: Chris Li Cc: Christian Brauner Cc: Daniel Wagner Cc: Danilo Krummrich Cc: Dan Williams Cc: David Hildenbrand Cc: David Jeffery Cc: David Rientjes Cc: Greg Kroah-Hartman Cc: Guixin Liu Cc: "H. Peter Anvin" Cc: Hugh Dickins Cc: Ilpo Järvinen Cc: Ingo Molnar Cc: Ira Weiny Cc: Jann Horn Cc: Jason Gunthorpe Cc: Jens Axboe Cc: Joanthan Cameron Cc: Joel Granados Cc: Johannes Weiner Cc: Jonathan Corbet Cc: Lennart Poettering Cc: Leon Romanovsky Cc: Leon Romanovsky Cc: Lukas Wunner Cc: Marc Rutland Cc: Masahiro Yamada Cc: Matthew Maurer Cc: Miguel Ojeda Cc: Myugnjoo Ham Cc: Parav Pandit Cc: Pratyush Yadav Cc: Randy Dunlap Cc: Roman Gushchin Cc: Saeed Mahameed Cc: Samiullah Khawaja Cc: Song Liu Cc: Steven Rostedt Cc: Stuart Hayes Cc: Tejun Heo Cc: Thomas Gleinxer Cc: Thomas Weißschuh Cc: Vincent Guittot Cc: William Tu Cc: Yoann Congal Cc: Zhu Yanjun Cc: Zijun Hu Signed-off-by: Andrew Morton

Merge tag 'for-linus-fwctl' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma

2025-03-29T17:45:20+00:00

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 ...

Documentation: dma-buf: heaps: Add heap name definitions

2025-03-12T22:49:02+00:00

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 Signed-off-by: Maxime Ripard Signed-off-by: Jonathan Corbet Link: https://lore.kernel.org/r/20250306135114.1943738-1-mripard@kernel.org

fwctl: Add documentation

2025-03-06T19:13:13+00:00

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 Link: https://lore.kernel.org/r/20240603114250.5325279c@kernel.org Acked-by: Daniel Vetter Link: https://lore.kernel.org/r/ZrHY2Bds7oF7KRGz@phenom.ffwll.local Reviewed-by: Jonathan Cameron Reviewed-by: Dave Jiang Reviewed-by: Shannon Nelson Reviewed-by: Bagas Sanjaya Signed-off-by: Jason Gunthorpe

Merge tag 'char-misc-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

2025-01-28T00:51:51+00:00

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 ...

docs: ntsync: Add documentation for the ntsync uAPI.

2025-01-08T12:18:12+00:00

Add an overall explanation of the driver architecture, and complete and precise specification for its intended behaviour. Signed-off-by: Elizabeth Figura Link: https://lore.kernel.org/r/20241213193511.457338-30-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman

exec: Add a new AT_EXECVE_CHECK flag to execveat(2)

2024-12-19T01:00:29+00:00

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 Cc: Christian Brauner Cc: Kees Cook Acked-by: Paul Moore Reviewed-by: Serge Hallyn Reviewed-by: Jeff Xu Tested-by: Jeff Xu Link: https://docs.python.org/3/library/io.html#io.open_code [1] Signed-off-by: Mickaël Salaün Link: https://lore.kernel.org/r/20241212174223.389435-2-mic@digikod.net Signed-off-by: Kees Cook