linux-toradex.git/drivers/powercap/intel_rapl_msr.c, branch v7.2-rc5

powercap: intel_rapl: Consolidate PL4 and PMU support flags into rapl_defaults

2026-04-01T14:03:05+00:00

Currently, PL4 and MSR-based RAPL PMU support are detected using
separate CPU ID tables (pl4_support_ids and pmu_support_ids) in the
MSR driver probe path. This creates a maintenance burden since adding
a new CPU requires updates in two places: the rapl_ids table and one
or both of these capability tables.

Consolidate PL4 and PMU capability information directly into
struct rapl_defaults by adding msr_pl4_support and msr_pmu_support
flags. This allows per-CPU capability to be expressed in a single
place alongside other per-CPU defaults, eliminating the duplicate
CPU ID tables entirely.

No functional changes are intended.

Co-developed-by: Zhang Rui 
Signed-off-by: Zhang Rui 
Acked-by: Srinivas Pandruvada 
Signed-off-by: Kuppuswamy Sathyanarayanan 
Link: https://patch.msgid.link/20260331211950.3329932-8-sathyanarayanan.kuppuswamy@linux.intel.com
Signed-off-by: Rafael J. Wysocki

powercap: intel_rapl: Move MSR primitives to MSR driver

2026-04-01T14:03:05+00:00

MSR-specific RAPL primitives differ from those used by TPMI and MMIO
interfaces. Keeping them in the common driver requires
interface-specific handling logic and makes the common layer
unnecessarily complex.

Move the MSR primitive definitions and associated bitmasks into the
MSR interface driver. This change includes:

 1. Move MSR-specific bitmask definitions to RAPL MSR driver.
 2. Add MSR-local struct rapl_primitive_info instance and assign it to
    priv->rpi during MSR probe.
 3. Remove the primitive assignment logic from rapl_config() in the
    common driver.

No functional changes are intended.

Co-developed-by: Zhang Rui 
Signed-off-by: Zhang Rui 
Signed-off-by: Kuppuswamy Sathyanarayanan 
Link: https://patch.msgid.link/20260331211950.3329932-7-sathyanarayanan.kuppuswamy@linux.intel.com
Signed-off-by: Rafael J. Wysocki

powercap: intel_rapl: Move MSR default settings into MSR interface driver

2026-04-01T14:03:04+00:00

MSR-specific RAPL defaults differ from those used by the TPMI interface.
The MMIO and MSR interfaces shared the same rapl_defaults pointer in the
common driver, but MMIO does not require the CPU-specific variations
needed by MSR. Keeping these in the common driver adds unnecessary
complexity and MSR-specific initialization.

Move MSR defaults and CPU matching into the MSR interface driver.

Moves
-----
  * Move rapl_check_unit_atom(), set_floor_freq_atom(), and
    rapl_compute_time_window_atom() into intel_rapl_msr.c.
  * Move MSR unit-field GENMASK definitions and local constants.
  * Move all MSR-related rapl_defaults tables and the CPU-ID matching
    logic (rapl_ids[]) into the MSR driver.
  * Move iosf_mbi dependencies (floor-frequency control and related MBI
    register definitions) as they are MSR-platform specific.

Modifications
-------------
  * Replace the common driver's platform-device manual alloc/add sequence
    with platform_device_register_data() in the MSR driver to pass
    matching rapl_defaults as platform_data.
  * Update MSR driver probe to assign pdev->dev.platform_data to
    priv->defaults.
  * Update Atom helper functions to use rp->lead_cpu directly for MSR
    reads/writes instead of the generic get_rid().
  * Update Atom floor frequency logic to access defaults via the
    package private data pointer.
  * Convert MSR device creation from fs_initcall() to module_init().
    This preserves existing enumeration behavior as the driver was
    already using module_init().
  * Since rapl_ids need to exist after boot, remove __initconst
    specifier.

No functional changes are expected.

Co-developed-by: Zhang Rui 
Signed-off-by: Zhang Rui 
Signed-off-by: Kuppuswamy Sathyanarayanan 
Acked-by: Srinivas Pandruvada 
Link: https://patch.msgid.link/20260331211950.3329932-2-sathyanarayanan.kuppuswamy@linux.intel.com
Signed-off-by: Rafael J. Wysocki

powercap: intel_rapl: Add a symbol namespace for intel_rapl exports

2026-03-05T14:52:38+00:00

Cleanup of the intel_rapl common driver requires introducing additional
exported helper and lifecycle functions. Before adding new exports,
create a dedicated symbol namespace for intel_rapl and update the
relevant interface drivers to explicitly import it.

This makes the intended usage of these symbols explicit, avoids
polluting the global namespace, and prepares the codebase for the
ongoing RAPL refactoring.

No functional changes are intended.

Signed-off-by: Kuppuswamy Sathyanarayanan 
Acked-by: Srinivas Pandruvada 
Link: https://patch.msgid.link/20260212233044.329790-2-sathyanarayanan.kuppuswamy@linux.intel.com
Signed-off-by: Rafael J. Wysocki

powercap: intel_rapl: Remove incorrect CPU check in PMU context

2026-02-11T20:03:39+00:00

The RAPL MSR read path incorrectly validates CPU context when called
from the PMU subsystem:

    if (atomic) {
        if (unlikely(smp_processor_id() != cpu))
            return -EIO;
        rdmsrq(ra->reg.msr, ra->value);
    }

This check fails for package-scoped MSRs like RAPL energy counters,
which are readable from any CPU within the package.

The perf tool avoids hitting this check by validating against
/sys/bus/event_source/devices/power/cpumask before opening events.
However, turbostat does not perform this validation and may attempt
reads from non-lead CPUs, causing the check to fail and return zero
power values.

Since package-scoped MSRs are architecturally accessible from any CPU
in the package, remove the CPU matching check.

Also rename 'atomic' to 'pmu_ctx' to clarify this indicates PMU context
where rdmsrq() can be used directly instead of rdmsrl_safe_on_cpu().

Fixes: 748d6ba43afd ("powercap: intel_rapl: Enable MSR-based RAPL PMU support")
Signed-off-by: Kuppuswamy Sathyanarayanan 
Tested-by: Furquim Ulisses 
Reviewed-by: Srinivas Pandruvada 
Link: https://patch.msgid.link/20260209234310.1440722-2-sathyanarayanan.kuppuswamy@linux.intel.com
Signed-off-by: Rafael J. Wysocki

powercap: intel_rapl: Add PL4 support for Ice Lake

2026-01-15T20:14:54+00:00

Microsoft Surface Pro 7 firmware throttles the processor upon
boot/resume. Userspace needs to be able to restore the correct value.

Link: https://github.com/linux-surface/linux-surface/issues/706
Signed-off-by: Daniel Tang 
Link: https://patch.msgid.link/6088605.ChMirdbgyp@daniel-desktop3
Signed-off-by: Rafael J. Wysocki

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: 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