linux-toradex.git/drivers/powercap, branch v6.19-rc2

powercap: intel_rapl: Fix possible recursive lock warning

2025-12-17T16:24:28+00:00

With the RAPL PMU addition, there is a recursive locking when CPU online
callback function calls rapl_package_add_pmu(). Here cpu_hotplug_lock
is already acquired by cpuhp_thread_fun() and rapl_package_add_pmu()
tries to acquire again.

<4>[ 8.197433] ============================================
<4>[ 8.197437] WARNING: possible recursive locking detected
<4>[ 8.197440] 6.19.0-rc1-lgci-xe-xe-4242-05b7c58b3367dca84+ #1 Not tainted
<4>[ 8.197444] --------------------------------------------
<4>[ 8.197447] cpuhp/0/20 is trying to acquire lock:
<4>[ 8.197450] ffffffff83487870 (cpu_hotplug_lock){++++}-{0:0}, at:
rapl_package_add_pmu+0x37/0x370 [intel_rapl_common]
<4>[ 8.197463]
but task is already holding lock:
<4>[ 8.197466] ffffffff83487870 (cpu_hotplug_lock){++++}-{0:0}, at:
cpuhp_thread_fun+0x6d/0x290
<4>[ 8.197477]
other info that might help us debug this:
<4>[ 8.197480] Possible unsafe locking scenario:

<4>[ 8.197483] CPU0
<4>[ 8.197485] ----
<4>[ 8.197487] lock(cpu_hotplug_lock);
<4>[ 8.197490] lock(cpu_hotplug_lock);
<4>[ 8.197493]
*** DEADLOCK ***
..
..
<4>[ 8.197542] __lock_acquire+0x146e/0x2790
<4>[ 8.197548] lock_acquire+0xc4/0x2c0
<4>[ 8.197550] ? rapl_package_add_pmu+0x37/0x370 [intel_rapl_common]
<4>[ 8.197556] cpus_read_lock+0x41/0x110
<4>[ 8.197558] ? rapl_package_add_pmu+0x37/0x370 [intel_rapl_common]
<4>[ 8.197561] rapl_package_add_pmu+0x37/0x370 [intel_rapl_common]
<4>[ 8.197565] rapl_cpu_online+0x85/0x87 [intel_rapl_msr]
<4>[ 8.197568] ? __pfx_rapl_cpu_online+0x10/0x10 [intel_rapl_msr]
<4>[ 8.197570] cpuhp_invoke_callback+0x41f/0x6c0
<4>[ 8.197573] ? cpuhp_thread_fun+0x6d/0x290
<4>[ 8.197575] cpuhp_thread_fun+0x1e2/0x290
<4>[ 8.197578] ? smpboot_thread_fn+0x26/0x290
<4>[ 8.197581] smpboot_thread_fn+0x12f/0x290
<4>[ 8.197584] ? __pfx_smpboot_thread_fn+0x10/0x10
<4>[ 8.197586] kthread+0x11f/0x250
<4>[ 8.197589] ? __pfx_kthread+0x10/0x10
<4>[ 8.197592] ret_from_fork+0x344/0x3a0
<4>[ 8.197595] ? __pfx_kthread+0x10/0x10
<4>[ 8.197597] ret_from_fork_asm+0x1a/0x30
<4>[ 8.197604] 

Fix this issue in the same way as rapl powercap package domain is added
from the same CPU online callback by introducing another interface which
doesn't call cpus_read_lock(). Add rapl_package_add_pmu_locked() and
rapl_package_remove_pmu_locked() which don't call cpus_read_lock().

Fixes: 748d6ba43afd ("powercap: intel_rapl: Enable MSR-based RAPL PMU support")
Reported-by: Borah, Chaitanya Kumar 
Closes: https://lore.kernel.org/linux-pm/5427ede1-57a0-43d1-99f3-8ca4b0643e82@intel.com/T/#u
Tested-by: Kuppuswamy Sathyanarayanan 
Tested-by: RavitejaX Veesam 
Signed-off-by: Srinivas Pandruvada 
Link: https://patch.msgid.link/20251217153455.3560176-1-srinivas.pandruvada@linux.intel.com
Signed-off-by: Rafael J. Wysocki

powercap: fix sscanf() error return value handling

2025-12-15T11:33:59+00:00

Fix inconsistent error handling for sscanf() return value check.

Implicit boolean conversion is used instead of explicit return
value checks. The code checks if (!sscanf(...)) which is incorrect
because:
 1. sscanf returns the number of successfully parsed items
 2. On success, it returns 1 (one item passed)
 3. On failure, it returns 0 or EOF
 4. The check 'if (!sscanf(...))' is wrong because it treats
    success (1) as failure

All occurrences of sscanf() now uses explicit return value check.
With this behavior it returns '-EINVAL' when parsing fails (returns
0 or EOF), and continues when parsing succeeds (returns 1).

Signed-off-by: Sumeet Pawnikar 
[ rjw: Subject and changelog edits ]
Link: https://patch.msgid.link/20251207151549.202452-1-sumeet4linux@gmail.com
Signed-off-by: Rafael J. Wysocki

powercap: fix race condition in register_control_type()

2025-12-15T11:29:11+00:00

The device becomes visible to userspace via device_register()
even before it fully initialized by idr_init(). If userspace
or another thread tries to register a zone immediately after
device_register(), the control_type_valid() will fail because
the control_type is not yet in the list. The IDR is not yet
initialized, so this race condition causes zone registration
failure.

Move idr_init() and list addition before device_register()
fix the race condition.

Signed-off-by: Sumeet Pawnikar 
[ rjw: Subject adjustment, empty line added ]
Link: https://patch.msgid.link/20251205190216.5032-1-sumeet4linux@gmail.com
Signed-off-by: Rafael J. Wysocki

Merge tag 'devicetree-for-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux

2025-12-04T23:50:37+00:00

Pull devicetree updates from Rob Herring:
 "DT bindings:

   - Convert lattice,ice40-fpga-mgr, apm,xgene-storm-dma,
     brcm,sr-thermal, amazon,al-thermal, brcm,ocotp, mt8173-mdp, Actions
     Owl SPS, Marvell AP80x System Controller, Marvell CP110 System
     Controller, cznic,moxtet, and apm,xgene-slimpro-mbox to DT schema
     format

   - Add i.MX95 fsl,irqsteer, MT8365 Mali Bifrost GPU, Anvo ANV32C81W
     EEPROM, and Microchip pic64gx PLIC

   - Add missing LGE, AMD Seattle, and APM X-Gene SoC platform
     compatibles

   - Updates to brcm,bcm2836-l1-intc, brcm,bcm2835-hvs, and bcm2711-hdmi
     bindings to fix warnings on BCM2712 platforms

   - Drop obsolete db8500-thermal.txt

   - Treewide clean-up of extra blank lines and inconsistent quoting

   - Ensure all .dtbo targets are applied to a base .dtb

   - Speed up dt_binding_check by skipping running validation on empty
     examples

  DT core:

   - Add of_machine_device_match() and of_machine_get_match_data()
     helpers and convert users treewide

   - Fix bounds checking of address properties in FDT code. Rework the
     code to have a single implementation of the bounds checks.

   - Rework of_irq_init() to ignore any implicit interrupt-parent (i.e.
     in a parent node) on nodes without an interrupt. This matches the
     spec description and fixes some RISC-V platforms.

   - Avoid a spurious message on overlay removal

   - Skip DT kunit tests on RISCV+ACPI"

* tag 'devicetree-for-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: (55 commits)
  dt-bindings: kbuild: Skip validating empty examples
  dt-bindings: interrupt-controller: brcm,bcm2836-l1-intc: Drop interrupt-controller requirement
  dt-bindings: display: Fix brcm,bcm2835-hvs bindings for BCM2712
  dt-bindings: display: bcm2711-hdmi: Add interrupt details for BCM2712
  of: Skip devicetree kunit tests when RISCV+ACPI doesn't populate root node
  soc: tegra: Simplify with of_machine_device_match()
  soc: qcom: ubwc: Simplify with of_machine_get_match_data()
  powercap: dtpm: Simplify with of_machine_get_match_data()
  platform: surface: Simplify with of_machine_get_match_data()
  irqchip/atmel-aic: Simplify with of_machine_get_match_data()
  firmware: qcom: scm: Simplify with of_machine_device_match()
  cpuidle: big_little: Simplify with of_machine_device_match()
  cpufreq: sun50i: Simplify with of_machine_device_match()
  cpufreq: mediatek: Simplify with of_machine_get_match_data()
  cpufreq: dt-platdev: Simplify with of_machine_get_match_data()
  of: Add wrappers to match root node with OF device ID tables
  dt-bindings: eeprom: at25: Add Anvo ANV32C81W
  of/reserved_mem: Simplify the logic of __reserved_mem_alloc_size()
  of/reserved_mem: Simplify the logic of fdt_scan_reserved_mem_reg_nodes()
  of/reserved_mem: Simplify the logic of __reserved_mem_reserve_reg()
  ...

powercap: dtpm: Simplify with of_machine_get_match_data()

2025-11-27T01:43:02+00:00

Replace open-coded getting root OF node, matching against it and getting
the match data with new of_machine_get_match_data() helper.

Signed-off-by: Krzysztof Kozlowski 
Reviewed-by: Lukasz Luba 
Reviewed-by: AngeloGioacchino Del Regno 
Tested-by: AngeloGioacchino Del Regno 
Link: https://patch.msgid.link/20251112-b4-of-match-matchine-data-v2-9-d46b72003fd6@linaro.org
Signed-off-by: Rob Herring (Arm)

powercap: intel_rapl: Enable MSR-based RAPL PMU support

2025-11-21T20:47:08+00:00

Currently, RAPL PMU support requires adding CPU model entries to
arch/x86/events/rapl.c for each new generation. However, RAPL MSRs are
not architectural and require platform-specific customization, making
arch/x86 an inappropriate location for this functionality.

The powercap subsystem already handles RAPL functionality and is the
natural place to consolidate all RAPL features. The powercap RAPL
driver already includes PMU support for TPMI-based RAPL interfaces,
making it straightforward to extend this support to MSR-based RAPL
interfaces as well.

This consolidation eliminates the need to maintain RAPL support in
multiple subsystems and provides a unified approach for both TPMI and
MSR-based RAPL implementations.

The MSR-based PMU support includes the following updates:

1. Register MSR-based PMU support for the supported platforms
and unregister it when no online CPUs remain in the package.

2. Remove existing checks that restrict RAPL PMU support to TPMI-based
interfaces and extend the logic to allow MSR-based RAPL interfaces.

3. Define a CPU model list to determine which processors should
register RAPL PMU interface through the powercap driver for
MSR-based RAPL, excluding those that support TPMI interface.
This list prevents conflicts with existing arch/x86 PMU code
that already registers RAPL PMU for some processors. Add
Panther Lake & Wildcat Lake to the CPU models list.

Signed-off-by: Kuppuswamy Sathyanarayanan
Reviewed-by: Srinivas Pandruvada
[ rjw: Changelog edits ]
Link: https://patch.msgid.link/20251121000539.386069-3-sathyanarayanan.kuppuswamy@linux.intel.com
Signed-off-by: Rafael J. Wysocki

powercap: intel_rapl: Prepare read_raw() interface for atomic-context callers

2025-11-21T20:47:08+00:00

The current read_raw() implementation of the TPMI, MMIO and MSR
interfaces does not distinguish between atomic and non-atomic callers.

rapl_msr_read_raw() uses rdmsrq_safe_on_cpu(), which can sleep and
issue cross CPU calls. When MSR-based RAPL PMU support is enabled, PMU
event handlers can invoke this function from atomic context where
sleeping or rescheduling is not allowed. In atomic context, the caller
is already executing on the target CPU, so a direct rdmsrq() is
sufficient.

To support such usage, introduce an atomic flag to the read_raw()
interface to allow callers pass the context information. Modify the
common RAPL code to propagate this flag, and set the flag to reflect
the calling contexts.

Utilize the atomic flag in rapl_msr_read_raw() to perform direct MSR
read with rdmsrq() when running in atomic context, and a sanity check
to ensure target CPU matches the current CPU for such use cases.

The TPMI and MMIO implementations do not require special atomic
handling, so the flag is ignored in those paths.

This is a preparatory patch for adding MSR-based RAPL PMU support.

Signed-off-by: Kuppuswamy Sathyanarayanan 
Reviewed-by: Srinivas Pandruvada 
[ rjw: Subject tweak ]
Link: https://patch.msgid.link/20251121000539.386069-2-sathyanarayanan.kuppuswamy@linux.intel.com
Signed-off-by: Rafael J. Wysocki

powercap: intel_rapl: Add support for Nova Lake processors

2025-11-18T14:39:29+00:00

Add RAPL support for Intel Nova Lake and Nova Lake L processors using
the core defaults configuration.

Signed-off-by: Kaushlendra Kumar 
[ rjw: Subject and changelog edits, rebase ]
Link: https://patch.msgid.link/20251028101814.3482508-1-kaushlendra.kumar@intel.com
Signed-off-by: Rafael J. Wysocki

powercap: intel_rapl: Add support for Wildcat Lake platform

2025-10-30T19:15:02+00:00

Add Wildcat Lake to the list of supported processors for RAPL.

Signed-off-by: Srinivas Pandruvada 
Link: https://patch.msgid.link/20251023174532.1882008-1-srinivas.pandruvada@linux.intel.com
Signed-off-by: Rafael J. Wysocki

powercap: idle_inject: use us_to_ktime() where appropriate

2025-08-21T19:57:54+00:00

Convert values in microseconds to ktime using us_to_ktime() instead of
multiplying them by NSEC_PER_USEC and using ns_to_ktime() for the
conversion.

Signed-off-by: Xichao Zhao 
Link: https://patch.msgid.link/20250813075433.464786-1-zhao.xichao@vivo.com
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki