kernel/linux.git/drivers/powercap/dtpm_cpu.c, branch v6.12.80

powercap: dtpm_cpu: Fix NULL pointer dereference in get_pd_power_uw()

2025-08-15T10:13:36+00:00

[ Upstream commit 46dc57406887dd02565cb264224194a6776d882b ] The get_pd_power_uw() function can crash with a NULL pointer dereference when em_cpu_get() returns NULL. This occurs when a CPU becomes impossible during runtime, causing get_cpu_device() to return NULL, which propagates through em_cpu_get() and leads to a crash when em_span_cpus() dereferences the NULL pointer. Add a NULL check after em_cpu_get() and return 0 if unavailable, matching the existing fallback behavior in __dtpm_cpu_setup(). Fixes: eb82bace8931 ("powercap/drivers/dtpm: Scale the power with the load") Signed-off-by: Sivan Zohar-Kotzer Link: https://patch.msgid.link/20250701221355.96916-1-sivany32@gmail.com [ rjw: Drop an excess empty code line ] Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

powercap: DTPM: Avoid explicit cpumask allocation on stack

2024-04-16T11:33:03+00:00

In general it's preferable to avoid placing cpumasks on the stack, as for large values of NR_CPUS these can consume significant amounts of stack space and make stack overflows more likely. Use cpumask_weight_and() to avoid the need for a temporary cpumask on the stack. Signed-off-by: Dawei Li Signed-off-by: Rafael J. Wysocki

Merge branch 'pm-em'

2024-03-11T14:59:51+00:00

Merge Enery Model changes for 6.9-rc1: - Allow the Energy Model to be updated dynamically (Lukasz Luba). * pm-em: (24 commits) PM: EM: Fix nr_states warnings in static checks Documentation: EM: Update with runtime modification design PM: EM: Add em_dev_compute_costs() PM: EM: Remove old table PM: EM: Change debugfs configuration to use runtime EM table data drivers/thermal/devfreq_cooling: Use new Energy Model interface drivers/thermal/cpufreq_cooling: Use new Energy Model interface powercap/dtpm_devfreq: Use new Energy Model interface to get table powercap/dtpm_cpu: Use new Energy Model interface to get table PM: EM: Optimize em_cpu_energy() and remove division PM: EM: Support late CPUs booting and capacity adjustment PM: EM: Add performance field to struct em_perf_state and optimize PM: EM: Add em_perf_state_from_pd() to get performance states table PM: EM: Introduce em_dev_update_perf_domain() for EM updates PM: EM: Add functions for memory allocations for new EM tables PM: EM: Use runtime modified EM for CPUs energy estimation in EAS PM: EM: Introduce runtime modifiable table PM: EM: Split the allocation and initialization of the EM table PM: EM: Check if the get_cost() callback is present in em_compute_costs() PM: EM: Introduce em_compute_costs() ...

powercap: dtpm_cpu: Fix error check against freq_qos_add_request()

2024-02-16T19:02:31+00:00

The caller of the function freq_qos_add_request() checks again a non zero value but freq_qos_add_request() can return '1' if the request already exists. Therefore, the setup function fails while the QoS request actually did not failed. Fix that by changing the check against a negative value like all the other callers of the function. Fixes: 0e8f68d7f0485 ("Add CPU energy model based support") Signed-off-by: Daniel Lezcano Signed-off-by: Rafael J. Wysocki

powercap/dtpm_cpu: Use new Energy Model interface to get table

2024-02-08T14:00:31+00:00

Energy Model framework support modifications at runtime of the power values. Use the new EM table API which is protected with RCU. Align the code so that this RCU read section is short. This change is not expected to alter the general functionality. Reviewed-by: Dietmar Eggemann Tested-by: Dietmar Eggemann Signed-off-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki

powercap: DTPM: Fix missing cpufreq_cpu_put() calls

2023-12-05T19:51:24+00:00

The policy returned by cpufreq_cpu_get() has to be released with the help of cpufreq_cpu_put() to balance its kobject reference counter properly. Add the missing calls to cpufreq_cpu_put() in the code. Fixes: 0aea2e4ec2a2 ("powercap/dtpm_cpu: Reset per_cpu variable in the release function") Fixes: 0e8f68d7f048 ("powercap/drivers/dtpm: Add CPU energy model based support") Cc: v5.16+ # v5.16+ Signed-off-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki

powercap: DTPM: Fix unneeded conversions to micro-Watts

2023-11-28T14:15:14+00:00

The power values coming from the Energy Model are already in uW. The PowerCap and DTPM frameworks operate on uW, so all places should just use the values from the EM. Fix the code by removing all of the conversion to uW still present in it. Fixes: ae6ccaa65038 (PM: EM: convert power field to micro-Watts precision and align drivers) Cc: 5.19+ # v5.19+ Signed-off-by: Lukasz Luba [ rjw: Changelog edits ] Signed-off-by: Rafael J. Wysocki

Merge tag 'pm-5.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

2022-08-02T18:17:00+00:00

Pull power management updates from Rafael Wysocki: "These are mostly minor improvements all over including new CPU IDs for the Intel RAPL driver, an Energy Model rework to use micro-Watt as the power unit, cpufreq fixes and cleanus, cpuidle updates, devfreq updates, documentation cleanups and a new version of the pm-graph suite of utilities. Specifics: - Make cpufreq_show_cpus() more straightforward (Viresh Kumar). - Drop unnecessary CPU hotplug locking from store() used by cpufreq sysfs attributes (Viresh Kumar). - Make the ACPI cpufreq driver support the boost control interface on Zhaoxin/Centaur processors (Tony W Wang-oc). - Print a warning message on attempts to free an active cpufreq policy which should never happen (Viresh Kumar). - Fix grammar in the Kconfig help text for the loongson2 cpufreq driver (Randy Dunlap). - Use cpumask_var_t for an on-stack CPU mask in the ondemand cpufreq governor (Zhao Liu). - Add trace points for guest_halt_poll_ns grow/shrink to the haltpoll cpuidle driver (Eiichi Tsukata). - Modify intel_idle to treat C1 and C1E as independent idle states on Sapphire Rapids (Artem Bityutskiy). - Extend support for wakeirq to callback wrappers used during system suspend and resume (Ulf Hansson). - Defer waiting for device probe before loading a hibernation image till the first actual device access to avoid possible deadlocks reported by syzbot (Tetsuo Handa). - Unify device_init_wakeup() for PM_SLEEP and !PM_SLEEP (Bjorn Helgaas). - Add Raptor Lake-P to the list of processors supported by the Intel RAPL driver (George D Sworo). - Add Alder Lake-N and Raptor Lake-P to the list of processors for which Power Limit4 is supported in the Intel RAPL driver (Sumeet Pawnikar). - Make pm_genpd_remove() check genpd_debugfs_dir against NULL before attempting to remove it (Hsin-Yi Wang). - Change the Energy Model code to represent power in micro-Watts and adjust its users accordingly (Lukasz Luba). - Add new devfreq driver for Mediatek CCI (Cache Coherent Interconnect) (Johnson Wang). - Convert the Samsung Exynos SoC Bus bindings to DT schema of exynos-bus.c (Krzysztof Kozlowski). - Address kernel-doc warnings by adding the description for unused function parameters in devfreq core (Mauro Carvalho Chehab). - Use NULL to pass a null pointer rather than zero according to the function propotype in imx-bus.c (Colin Ian King). - Print error message instead of error interger value in tegra30-devfreq.c (Dmitry Osipenko). - Add checks to prevent setting negative frequency QoS limits for CPUs (Shivnandan Kumar). - Update the pm-graph suite of utilities to the latest revision 5.9 including multiple improvements (Todd Brandt). - Drop pme_interrupt reference from the PCI power management documentation (Mario Limonciello)" * tag 'pm-5.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (27 commits) powercap: RAPL: Add Power Limit4 support for Alder Lake-N and Raptor Lake-P PM: QoS: Add check to make sure CPU freq is non-negative PM: hibernate: defer device probing when resuming from hibernation intel_idle: make SPR C1 and C1E be independent cpufreq: ondemand: Use cpumask_var_t for on-stack cpu mask cpufreq: loongson2: fix Kconfig "its" grammar pm-graph v5.9 cpufreq: Warn users while freeing active policy cpufreq: scmi: Support the power scale in micro-Watts in SCMI v3.1 firmware: arm_scmi: Get detailed power scale from perf Documentation: EM: Switch to micro-Watts scale PM: EM: convert power field to micro-Watts precision and align drivers PM / devfreq: tegra30: Add error message for devm_devfreq_add_device() PM / devfreq: imx-bus: use NULL to pass a null pointer rather than zero PM / devfreq: shut up kernel-doc warnings dt-bindings: interconnect: samsung,exynos-bus: convert to dtschema PM / devfreq: mediatek: Introduce MediaTek CCI devfreq driver dt-bindings: interconnect: Add MediaTek CCI dt-bindings PM: domains: Ensure genpd_debugfs_dir exists before remove PM: runtime: Extend support for wakeirq for force_suspend|resume ...

PM: EM: convert power field to micro-Watts precision and align drivers

2022-07-15T17:17:30+00:00

The milli-Watts precision causes rounding errors while calculating efficiency cost for each OPP. This is especially visible in the 'simple' Energy Model (EM), where the power for each OPP is provided from OPP framework. This can cause some OPPs to be marked inefficient, while using micro-Watts precision that might not happen. Update all EM users which access 'power' field and assume the value is in milli-Watts. Solve also an issue with potential overflow in calculation of energy estimation on 32bit machine. It's needed now since the power value (thus the 'cost' as well) are higher. Example calculation which shows the rounding error and impact: power = 'dyn-power-coeff' * volt_mV * volt_mV * freq_MHz power_a_uW = (100 * 600mW * 600mW * 500MHz) / 10^6 = 18000 power_a_mW = (100 * 600mW * 600mW * 500MHz) / 10^9 = 18 power_b_uW = (100 * 605mW * 605mW * 600MHz) / 10^6 = 21961 power_b_mW = (100 * 605mW * 605mW * 600MHz) / 10^9 = 21 max_freq = 2000MHz cost_a_mW = 18 * 2000MHz/500MHz = 72 cost_a_uW = 18000 * 2000MHz/500MHz = 72000 cost_b_mW = 21 * 2000MHz/600MHz = 70 // <- artificially better cost_b_uW = 21961 * 2000MHz/600MHz = 73203 The 'cost_b_mW' (which is based on old milli-Watts) is misleadingly better that the 'cost_b_uW' (this patch uses micro-Watts) and such would have impact on the 'inefficient OPPs' information in the Cpufreq framework. This patch set removes the rounding issue. Signed-off-by: Lukasz Luba Acked-by: Daniel Lezcano Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

sched, drivers: Remove max param from effective_cpu_util()/sched_cpu_util()

2022-06-28T07:17:46+00:00

effective_cpu_util() already has a `int cpu' parameter which allows to retrieve the CPU capacity scale factor (or maximum CPU capacity) inside this function via an arch_scale_cpu_capacity(cpu). A lot of code calling effective_cpu_util() (or the shim sched_cpu_util()) needs the maximum CPU capacity, i.e. it will call arch_scale_cpu_capacity() already. But not having to pass it into effective_cpu_util() will make the EAS wake-up code easier, especially when the maximum CPU capacity reduced by the thermal pressure is passed through the EAS wake-up functions. Due to the asymmetric CPU capacity support of arm/arm64 architectures, arch_scale_cpu_capacity(int cpu) is a per-CPU variable read access via per_cpu(cpu_scale, cpu) on such a system. On all other architectures it is a a compile-time constant (SCHED_CAPACITY_SCALE). Signed-off-by: Dietmar Eggemann Signed-off-by: Peter Zijlstra (Intel) Acked-by: Vincent Guittot Tested-by: Lukasz Luba Link: https://lkml.kernel.org/r/20220621090414.433602-4-vdonnefort@google.com