Linux kernel documentation tree maintained by Jonathan Corbet http://mirrors.hust.edu.cn/git/lwn.git/atom?h=master 2026-04-17T21:09:02+00:00 2026-04-17T21:09:02+00:00 Linus Torvalds torvalds@linux-foundation.org 2026-04-17T21:09:02+00:00 urn:sha1:e2d10998e4293a27c0389870b5fdf736a71d61ef Pull devicetree updates from Rob Herring: "DT core: - Cleanup of the reserved memory code to keep CMA specifics in CMA code - Add and convert several users to new of_machine_get_match() helper - Validate nul termination in string properties - Update dtc to upstream v1.7.2-69-g53373d135579 - Limit matching reserved memory devices to /reserved-memory nodes - Fix some UAF in unittests - Remove Baikal SoC bus driver - Fix false DT_SPLIT_BINDING_PATCH checkpatch warning - Allow fw_devlink device-tree on x86 - Fix kerneldoc return description for of_property_count_elems_of_size() DT bindings: - Add fsl,imx25-aips, fsl,imx25-tcq, qcom,eliza-pdc, qcom,eliza-spmi-pmic-arb, qcom,hawi-imem, qcom,milos-imem, qcom,hawi-pdc, and lg,sw49410 bindings - Convert arm,vexpress-scc to DT schema - Deprecate Qualcomm generic CPU compatibles. Add Apple M3 CPU cores. - Move some dual-link display panels to the dual-link schema - Drop mux controller node name constraints - Remove Baikal SoC bus bindings - Fix a false warning in the thermal trip node binding" * tag 'devicetree-for-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: (39 commits) dt-bindings: display: panel: panel-simple: Add lg,sw49410 compatible dt-bindings: display: ti, am65x-dss: Fix AM62L DSS reg and clock constraints dt-bindings: display: simple: Move Innolux G156HCE-L01 panel to dual-link dt-bindings: display: simple: Move AUO 21.5" FHD to dual-link dt-bindings: thermal: Fix false warning with 'phandle' in trips nodes of: unittest: fix use-after-free in testdrv_probe() of: unittest: fix use-after-free in of_unittest_changeset() dt-bindings: qcom,pdc: document the Hawi Power Domain Controller dt-bindings: ARM: arm,vexpress-scc: convert to DT schema drivers/of: fdt: validate flat DT string properties before string use drivers/of: fdt: validate stdout-path properties before parsing them dt-bindings: sram: Document qcom,hawi-imem compatible dt-bindings: sram: Allow multiple-word prefixes to sram subnode dt-bindings: sram: Document qcom,milos-imem scripts/dtc: Update to upstream version v1.7.2-69-g53373d135579 of: property: Allow fw_devlink device-tree on x86 dt-bindings: arm: cpus: Add Apple M3 CPU core compatibles dt-bindings: display: lt8912b: Drop redundant endpoint properties dt-bindings: opp-v2: Fix example 3 CPU reg value dt-bindings: connector: add pd-disable dependency ... 2026-04-17T16:43:12+00:00 Linus Torvalds torvalds@linux-foundation.org 2026-04-17T16:43:12+00:00 urn:sha1:cb30bf881c5b4ee8b879558a2fce93d7de652955 Pull tracing updates from Steven Rostedt: - Fix printf format warning for bprintf sunrpc uses a trace_printk() that triggers a printf warning during the compile. Move the __printf() attribute around for when debugging is not enabled the warning will go away - Remove redundant check for EVENT_FILE_FL_FREED in event_filter_write() The FREED flag is checked in the call to event_file_file() and then checked again right afterward, which is unneeded - Clean up event_file_file() and event_file_data() helpers These helper functions played a different role in the past, but now with eventfs, the READ_ONCE() isn't needed. Simplify the code a bit and also add a warning to event_file_data() if the file or its data is not present - Remove updating file->private_data in tracing open All access to the file private data is handled by the helper functions, which do not use file->private_data. Stop updating it on open - Show ENUM names in function arguments via BTF in function tracing When showing the function arguments when func-args option is set for function tracing, if one of the arguments is found to be an enum, show the name of the enum instead of its number - Add new trace_call__##name() API for tracepoints Tracepoints are enabled via static_branch() blocks, where when not enabled, there's only a nop that is in the code where the execution will just skip over it. When tracing is enabled, the nop is converted to a direct jump to the tracepoint code. Sometimes more calculations are required to be performed to update the parameters of the tracepoint. In this case, trace_##name##_enabled() is called which is a static_branch() that gets enabled only when the tracepoint is enabled. This allows the extra calculations to also be skipped by the nop: if (trace_foo_enabled()) { x = bar(); trace_foo(x); } Where the x=bar() is only performed when foo is enabled. The problem with this approach is that there's now two static_branch() calls. One for checking if the tracepoint is enabled, and then again to know if the tracepoint should be called. The second one is redundant Introduce trace_call__foo() that will call the foo() tracepoint directly without doing a static_branch(): if (trace_foo_enabled()) { x = bar(); trace_call__foo(); } - Update various locations to use the new trace_call__##name() API - Move snapshot code out of trace.c Cleaning up trace.c to not be a "dump all", move the snapshot code out of it and into a new trace_snapshot.c file - Clean up some "%*.s" to "%*s" - Allow boot kernel command line options to be called multiple times Have options like: ftrace_filter=foo ftrace_filter=bar ftrace_filter=zoo Equal to: ftrace_filter=foo,bar,zoo - Fix ipi_raise event CPU field to be a CPU field The ipi_raise target_cpus field is defined as a __bitmask(). There is now a __cpumask() field definition. Update the field to use that - Have hist_field_name() use a snprintf() and not a series of strcat() It's safer to use snprintf() that a series of strcat() - Fix tracepoint regfunc balancing A tracepoint can define a "reg" and "unreg" function that gets called before the tracepoint is enabled, and after it is disabled respectively. But on error, after the "reg" func is called and the tracepoint is not enabled, the "unreg" function is not called to tear down what the "reg" function performed - Fix output that shows what histograms are enabled Event variables are displayed incorrectly in the histogram output Instead of "sched.sched_wakeup.$var", it is showing "$sched.sched_wakeup.var" where the '$' is in the incorrect location - Some other simple cleanups * tag 'trace-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (24 commits) selftests/ftrace: Add test case for fully-qualified variable references tracing: Fix fully-qualified variable reference printing in histograms tracepoint: balance regfunc() on func_add() failure in tracepoint_add_func() tracing: Rebuild full_name on each hist_field_name() call tracing: Report ipi_raise target CPUs as cpumask tracing: Remove duplicate latency_fsnotify() stub tracing: Preserve repeated trace_trigger boot parameters tracing: Append repeated boot-time tracing parameters tracing: Remove spurious default precision from show_event_trigger/filter formats cpufreq: Use trace_call__##name() at guarded tracepoint call sites tracing: Remove tracing_alloc_snapshot() when snapshot isn't defined tracing: Move snapshot code out of trace.c and into trace_snapshot.c mm: damon: Use trace_call__##name() at guarded tracepoint call sites btrfs: Use trace_call__##name() at guarded tracepoint call sites spi: Use trace_call__##name() at guarded tracepoint call sites i2c: Use trace_call__##name() at guarded tracepoint call sites kernel: Use trace_call__##name() at guarded tracepoint call sites tracepoint: Add trace_call__##name() API tracing: trace_mmap.h: fix a kernel-doc warning tracing: Pretty-print enum parameters in function arguments ... 2026-04-14T02:47:52+00:00 Linus Torvalds torvalds@linux-foundation.org 2026-04-14T02:47:52+00:00 urn:sha1:d7c8087a9cd8979d70edfe7c7feda9423feae3ab Pull power management updates from Rafael Wysocki: "Once again, cpufreq is the most active development area, mostly because of the new feature additions and documentation updates in the amd-pstate driver, but there are also changes in the cpufreq core related to boost support and other assorted updates elsewhere. Next up are power capping changes due to the major cleanup of the Intel RAPL driver. On the cpuidle front, a new C-states table for Intel Panther Lake is added to the intel_idle driver, the stopped tick handling in the menu and teo governors is updated, and there are a couple of cleanups. Apart from the above, support for Tegra114 is added to devfreq and there are assorted cleanups of that code, there are also two updates of the operating performance points (OPP) library, two minor updates related to hibernation, and cpupower utility man pages updates and cleanups. Specifics: - Update qcom-hw DT bindings to include Eliza hardware (Abel Vesa) - Update cpufreq-dt-platdev blocklist (Faruque Ansari) - Minor updates to driver and dt-bindings for Tegra (Thierry Reding, Rosen Penev) - Add MAINTAINERS entry for CPPC driver (Viresh Kumar) - Add support for new features: CPPC performance priority, Dynamic EPP, Raw EPP, and new unit tests for them to amd-pstate (Gautham Shenoy, Mario Limonciello) - Fix sysfs files being present when HW missing and broken/outdated documentation in the amd-pstate driver (Ninad Naik, Gautham Shenoy) - Pass the policy to cpufreq_driver->adjust_perf() to avoid using cpufreq_cpu_get() in the .adjust_perf() callback in amd-pstate which leads to a scheduling-while-atomic bug (K Prateek Nayak) - Clean up dead code in Kconfig for cpufreq (Julian Braha) - Remove max_freq_req update for pre-existing cpufreq policy and add a boost_freq_req QoS request to save the boost constraint instead of overwriting the last scaling_max_freq constraint (Pierre Gondois) - Embed cpufreq QoS freq_req objects in cpufreq policy so they all are allocated in one go along with the policy to simplify lifetime rules and avoid error handling issues (Viresh Kumar) - Use DMI max speed when CPPC is unavailable in the acpi-cpufreq scaling driver (Henry Tseng) - Switch policy_is_shared() in cpufreq to using cpumask_nth() instead of cpumask_weight() because the former is more efficient (Yury Norov) - Use sysfs_emit() in sysfs show functions for cpufreq governor attributes (Thorsten Blum) - Update intel_pstate to stop returning an error when "off" is written to its status sysfs attribute while the driver is already off (Fabio De Francesco) - Include current frequency in the debug message printed by __cpufreq_driver_target() (Pengjie Zhang) - Refine stopped tick handling in the menu cpuidle governor and rearrange stopped tick handling in the teo cpuidle governor (Rafael Wysocki) - Add Panther Lake C-states table to the intel_idle driver (Artem Bityutskiy) - Clean up dead dependencies on CPU_IDLE in Kconfig (Julian Braha) - Simplify cpuidle_register_device() with guard() (Huisong Li) - Use performance level if available to distinguish between rates in OPP debugfs (Manivannan Sadhasivam) - Fix scoped_guard in dev_pm_opp_xlate_required_opp() (Viresh Kumar) - Return -ENODATA if the snapshot image is not loaded (Alberto Garcia) - Remove inclusion of crypto/hash.h from hibernate_64.c on x86 (Eric Biggers) - Clean up and rearrange the intel_rapl power capping driver to make the respective interface drivers (TPMI, MSR, and MMOI) hold their own settings and primitives and consolidate PL4 and PMU support flags into rapl_defaults (Kuppuswamy Sathyanarayanan) - Correct kernel-doc function parameter names in the power capping core code (Randy Dunlap) - Remove unneeded casting for HZ_PER_KHZ in devfreq (Andy Shevchenko) - Use _visible attribute to replace create/remove_sysfs_files() in devfreq (Pengjie Zhang) - Add Tegra114 support to activity monitor device in tegra30-devfreq as a preparation to upcoming EMC controller support (Svyatoslav Ryhel) - Fix mistakes in cpupower man pages, add the boost and epp options to the cpupower-frequency-info man page, and add the perf-bias option to the cpupower-info man page (Roberto Ricci) - Remove unnecessary extern declarations from getopt.h in arguments parsing functions in cpufreq-set, cpuidle-info, cpuidle-set, cpupower-info, and cpupower-set utilities (Kaushlendra Kumar)" * tag 'pm-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (74 commits) cpufreq/amd-pstate: Add POWER_SUPPLY select for dynamic EPP cpupower: remove extern declarations in cmd functions cpuidle: Simplify cpuidle_register_device() with guard() PM / devfreq: tegra30-devfreq: add support for Tegra114 PM / devfreq: use _visible attribute to replace create/remove_sysfs_files() PM / devfreq: Remove unneeded casting for HZ_PER_KHZ MAINTAINERS: amd-pstate: Step down as maintainer, add Prateek as reviewer cpufreq: Pass the policy to cpufreq_driver->adjust_perf() cpufreq/amd-pstate: Pass the policy to amd_pstate_update() cpufreq/amd-pstate-ut: Add a unit test for raw EPP cpufreq/amd-pstate: Add support for raw EPP writes cpufreq/amd-pstate: Add support for platform profile class cpufreq/amd-pstate: add kernel command line to override dynamic epp cpufreq/amd-pstate: Add dynamic energy performance preference Documentation: amd-pstate: fix dead links in the reference section cpufreq/amd-pstate: Cache the max frequency in cpudata Documentation/amd-pstate: Add documentation for amd_pstate_floor_{freq,count} Documentation/amd-pstate: List amd_pstate_prefcore_ranking sysfs file Documentation/amd-pstate: List amd_pstate_hw_prefcore sysfs file amd-pstate-ut: Add a testcase to validate the visibility of driver attributes ... 2026-04-09T19:26:06+00:00 Rafael J. Wysocki rafael.j.wysocki@intel.com 2026-04-09T19:26:06+00:00 urn:sha1:bfb0315a2dc89a2f3b353b3b82efe8eeeac629b2 Merge ACPI processor driver updates and ACPI CPPC library updates for 7.1-rc1: - Address multiple assorted issues and clean up the code in the ACPI processor idle driver (Huisong Li) - Replace strlcat() in the ACPI processor idle drive with a better alternative (Andy Shevchenko) - Rearrange and clean up acpi_processor_errata_piix4() (Rafael Wysocki) - Move reference performance to capabilities and fix an uninitialized variable in the ACPI CPPC library (Pengjie Zhang) - Add support for the Performance Limited Register to the ACPI CPPC library (Sumit Gupta) - Add cppc_get_perf() API to read performance controls, extend cppc_set_epp_perf() for FFH/SystemMemory, and make the ACPI CPPC library warn on missing mandatory DESIRED_PERF register (Sumit Gupta) - Modify the cpufreq CPPC driver to update MIN_PERF/MAX_PERF in target callbacks to allow it to control performance bounds via standard scaling_min_freq and scaling_max_freq sysfs attributes and add sysfs documentation for the Performance Limited Register to it (Sumit Gupta) * acpi-processor: ACPI: processor: idle: Reset cpuidle on C-state list changes cpuidle: Extract and export no-lock variants of cpuidle_unregister_device() ACPI: processor: idle: Fix NULL pointer dereference in hotplug path ACPI: processor: idle: Reset power_setup_done flag on initialization failure ACPI: processor: Rearrange and clean up acpi_processor_errata_piix4() ACPI: processor: idle: Replace strlcat() with better alternative ACPI: processor: idle: Remove redundant static variable and rename cstate check function ACPI: processor: idle: Move max_cstate update out of the loop ACPI: processor: idle: Remove redundant cstate check in acpi_processor_power_init ACPI: processor: idle: Add missing bounds check in flatten_lpi_states() * acpi-cppc: ACPI: CPPC: Check cpc_read() return values consistently ACPI: CPPC: Fix uninitialized ref variable in cppc_get_perf_caps() ACPI: CPPC: Move reference performance to capabilities cpufreq: CPPC: Add sysfs documentation for perf_limited ACPI: CPPC: add APIs and sysfs interface for perf_limited cpufreq: cppc: Update MIN_PERF/MAX_PERF in target callbacks cpufreq: CPPC: Update cached perf_ctrls on sysfs write ACPI: CPPC: Extend cppc_set_epp_perf() for FFH/SystemMemory ACPI: CPPC: Warn on missing mandatory DESIRED_PERF register ACPI: CPPC: Add cppc_get_perf() API to read performance controls 2026-04-07T19:57:04+00:00 Mario Limonciello mario.limonciello@amd.com 2026-04-07T19:49:49+00:00 urn:sha1:679343977588781bd3effba79e9644aee4ee046c The dynamic EPP feature uses power_supply_reg_notifier() and power_supply_unreg_notifier() but doesn't declare a dependency on POWER_SUPPLY, causing linker errors when POWER_SUPPLY is not enabled. Add POWER_SUPPLY to the selects. Suggested-by: K Prateek Nayak <kprateek.nayak@amd.com> Fixes: e30ca6dd5345 ("cpufreq/amd-pstate: Add dynamic energy performance preference") Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202604040742.ySEdkuAa-lkp@intel.com/ Signed-off-by: Mario Limonciello <mario.limonciello@amd.com> Link: https://patch.msgid.link/20260407194949.310114-1-mario.limonciello@amd.com Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 2026-04-06T14:25:16+00:00 Rafael J. Wysocki rafael.j.wysocki@intel.com 2026-04-06T14:25:16+00:00 urn:sha1:d7d36c3a0977400b3a727741bb0468403f5a0cbe Pull CPUFreq Arm updates for 7.1 from Viresh Kumar: "- Update qcom-hw DT bindings to include Eliza hardware (Abel Vesa). - Update cpufreq-dt-platdev blocklist (Faruque Ansari). - Minor updates to driver and dt-bindings for Tegra (Thierry Reding and Rosen Penev). - Add MAINTAINERS entry for CPPC driver (Viresh Kumar)." * tag 'cpufreq-arm-updates-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm: cpufreq: tegra194: remove COMPILE_TEST cpufreq: Add QCS8300 to cpufreq-dt-platdev blocklist cpufreq: Add MAINTAINERS entry for CPPC driver cpufreq: tegra194: Rename Tegra239 to Tegra238 dt-bindings: arm: nvidia: Document the Tegra238 CCPLEX cluster dt-bindings: cpufreq: qcom-hw: document Eliza cpufreq hardware 2026-04-04T18:55:56+00:00 Rafael J. Wysocki rafael.j.wysocki@intel.com 2026-04-04T18:55:56+00:00 urn:sha1:5cdfedf68e6ee3905d36e387d49699d4d0848637 Pull amd-pstate new content for 7.1 (2026-04-02) from Mario Limonciello: "Add support for new features: * CPPC performance priority * Dynamic EPP * Raw EPP * New unit tests for new features Fixes for: * PREEMPT_RT * sysfs files being present when HW missing * Broken/outdated documentation" * tag 'amd-pstate-v7.1-2026-04-02' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/superm1/linux: (22 commits) MAINTAINERS: amd-pstate: Step down as maintainer, add Prateek as reviewer cpufreq: Pass the policy to cpufreq_driver->adjust_perf() cpufreq/amd-pstate: Pass the policy to amd_pstate_update() cpufreq/amd-pstate-ut: Add a unit test for raw EPP cpufreq/amd-pstate: Add support for raw EPP writes cpufreq/amd-pstate: Add support for platform profile class cpufreq/amd-pstate: add kernel command line to override dynamic epp cpufreq/amd-pstate: Add dynamic energy performance preference Documentation: amd-pstate: fix dead links in the reference section cpufreq/amd-pstate: Cache the max frequency in cpudata Documentation/amd-pstate: Add documentation for amd_pstate_floor_{freq,count} Documentation/amd-pstate: List amd_pstate_prefcore_ranking sysfs file Documentation/amd-pstate: List amd_pstate_hw_prefcore sysfs file amd-pstate-ut: Add a testcase to validate the visibility of driver attributes amd-pstate-ut: Add module parameter to select testcases amd-pstate: Introduce a tracepoint trace_amd_pstate_cppc_req2() amd-pstate: Add sysfs support for floor_freq and floor_count amd-pstate: Add support for CPPC_REQ2 and FLOOR_PERF x86/cpufeatures: Add AMD CPPC Performance Priority feature. amd-pstate: Make certain freq_attrs conditionally visible ... 2026-04-04T12:58:58+00:00 Rafael J. Wysocki rafael.j.wysocki@intel.com 2026-04-04T12:58:58+00:00 urn:sha1:35ed8fa05fb81fae4eb92ccc55dd6007d409e2f3 2026-04-02T16:30:24+00:00 K Prateek Nayak kprateek.nayak@amd.com 2026-03-16T08:18:49+00:00 urn:sha1:c03791085adcd61fa9b766ab303c7d0941d7378d cpufreq_cpu_get() can sleep on PREEMPT_RT in presence of concurrent writer(s), however amd-pstate depends on fetching the cpudata via the policy's driver data which necessitates grabbing the reference. Since schedutil governor can call "cpufreq_driver->update_perf()" during sched_tick/enqueue/dequeue with rq_lock held and IRQs disabled, fetching the policy object using the cpufreq_cpu_get() helper in the scheduler fast-path leads to "BUG: scheduling while atomic" on PREEMPT_RT [1]. Pass the cached cpufreq policy object in sg_policy to the update_perf() instead of just the CPU. The CPU can be inferred using "policy->cpu". The lifetime of cpufreq_policy object outlasts that of the governor and the cpufreq driver (allocated when the CPU is onlined and only reclaimed when the CPU is offlined / the CPU device is removed) which makes it safe to be referenced throughout the governor's lifetime. Closes:https://lore.kernel.org/all/20250731092316.3191-1-spasswolf@web.de/ [1] Fixes: 1d215f0319c2 ("cpufreq: amd-pstate: Add fast switch function for AMD P-State") Reported-by: Bert Karwatzki <spasswolf@web.de> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: K Prateek Nayak <kprateek.nayak@amd.com> Acked-by: Gary Guo <gary@garyguo.net> # Rust Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com> Reviewed-by: Zhongqiu Han <zhongqiu.han@oss.qualcomm.com> Link: https://lore.kernel.org/r/20260316081849.19368-3-kprateek.nayak@amd.com Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org> 2026-04-02T16:30:24+00:00 K Prateek Nayak kprateek.nayak@amd.com 2026-03-16T08:18:48+00:00 urn:sha1:86d71f1d7686cecebbafb371ad58c6ad7f80a93a All callers of amd_pstate_update() already have a reference to the cpufreq_policy object. Pass the entire policy object and grab the cpudata using "policy->driver_data" instead of passing the cpudata and unnecessarily grabbing another read-side reference to the cpufreq policy object when it is already available in the caller. No functional changes intended. Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: K Prateek Nayak <kprateek.nayak@amd.com> Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com> Link: https://lore.kernel.org/r/20260316081849.19368-2-kprateek.nayak@amd.com Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>