kernel.git/drivers/cpufreq/intel_pstate.c, branch linux-5.4.y

cpufreq: intel_pstate: Fix object lifecycle issue in update_qos_request()

2025-10-29T12:59:52Z

commit 69e5d50fcf4093fb3f9f41c4f931f12c2ca8c467 upstream. The cpufreq_cpu_put() call in update_qos_request() takes place too early because the latter subsequently calls freq_qos_update_request() that indirectly accesses the policy object in question through the QoS request object passed to it. Fortunately, update_qos_request() is called under intel_pstate_driver_lock, so this issue does not matter for changing the intel_pstate operation mode, but it theoretically can cause a crash to occur on CPU device hot removal (which currently can only happen in virt, but it is formally supported nevertheless). Address this issue by modifying update_qos_request() to drop the reference to the policy later. Fixes: da5c504c7aae ("cpufreq: intel_pstate: Implement QoS supported freq constraints") Cc: 5.4+ # 5.4+ Signed-off-by: Rafael J. Wysocki Reviewed-by: Zihuan Zhang Link: https://patch.msgid.link/2255671.irdbgypaU6@rafael.j.wysocki Signed-off-by: Greg Kroah-Hartman

cpufreq: intel_pstate: Drop ACPI _PSS states table patching

2023-08-11T09:53:53Z

commit e8a0e30b742f76ebd0f3b196973df4bf65d8fbbb upstream. After making acpi_processor_get_platform_limit() use the "no limit" value for its frequency QoS request when _PPC returns 0, it is not necessary to replace the frequency corresponding to the first _PSS return package entry with the maximum turbo frequency of the given CPU in intel_pstate_init_acpi_perf_limits() any more, so drop the code doing that along with the comment explaining it. Signed-off-by: Rafael J. Wysocki Tested-by: Hagar Hemdan Signed-off-by: Greg Kroah-Hartman

cpufreq: intel_pstate: Get per-CPU max freq via MSR_HWP_CAPABILITIES if available

2021-03-04T09:26:50Z

commit 6f67e060083a84a4cc364eab6ae40c717165fb0c upstream. Currently, when turbo is disabled (either by BIOS or by the user), the intel_pstate driver reads the max non-turbo frequency from the package-wide MSR_PLATFORM_INFO(0xce) register. However, on asymmetric platforms it is possible in theory that small and big core with HWP enabled might have different max non-turbo CPU frequency, because MSR_HWP_CAPABILITIES is per-CPU scope according to Intel Software Developer Manual. The turbo max freq is already per-CPU in current code, so make similar change to the max non-turbo frequency as well. Reported-by: Wendy Wang Signed-off-by: Chen Yu [ rjw: Subject and changelog edits ] Cc: 4.18+ # 4.18+: a45ee4d4e13b: cpufreq: intel_pstate: Change intel_pstate_get_hwp_max() argument Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

cpufreq: intel_pstate: Fix intel_pstate_get_hwp_max() for turbo disabled

2020-09-17T11:47:49Z

[ Upstream commit eacc9c5a927e474c173a5d53dd7fb8e306511768 ] This fixes the behavior of the scaling_max_freq and scaling_min_freq sysfs files in systems which had turbo disabled by the BIOS. Caleb noticed that the HWP is programmed to operate in the wrong P-state range on his system when the CPUFREQ policy min/max frequency is set via sysfs. This seems to be because in his system intel_pstate_get_hwp_max() is returning the maximum turbo P-state even though turbo was disabled by the BIOS, which causes intel_pstate to scale kHz frequencies incorrectly e.g. setting the maximum turbo frequency whenever the maximum guaranteed frequency is requested via sysfs. Tested-by: Caleb Callaway Signed-off-by: Francisco Jerez Acked-by: Srinivas Pandruvada [ rjw: Minor subject edits ] Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

cpufreq: intel_pstate: Refuse to turn off with HWP enabled

2020-09-17T11:47:49Z

[ Upstream commit 43298db3009f06fe5c69e1ca8b6cfc2565772fa1 ] After commit f6ebbcf08f37 ("cpufreq: intel_pstate: Implement passive mode with HWP enabled") it is possible to change the driver status to "off" via sysfs with HWP enabled, which effectively causes the driver to unregister itself, but HWP remains active and it forces the minimum performance, so even if another cpufreq driver is loaded, it will not be able to control the CPU frequency. For this reason, make the driver refuse to change the status to "off" with HWP enabled. Signed-off-by: Rafael J. Wysocki Acked-by: Srinivas Pandruvada Signed-off-by: Sasha Levin

cpufreq: intel_pstate: Fix EPP setting via sysfs in active mode

2020-09-03T09:26:53Z

[ Upstream commit de002c55cadfc2f6cdf0ed427526f6085d240238 ] Because intel_pstate_set_energy_pref_index() reads and writes the MSR_HWP_REQUEST register without using the cached value of it used by intel_pstate_hwp_boost_up() and intel_pstate_hwp_boost_down(), those functions may overwrite the value written by it and so the EPP value set via sysfs may be lost. To avoid that, make intel_pstate_set_energy_pref_index() take the cached value of MSR_HWP_REQUEST just like the other two routines mentioned above and update it with the new EPP value coming from user space in addition to updating the MSR. Note that the MSR itself still needs to be updated too in case hwp_boost is unset or the boosting mechanism is not active at the EPP change time. Fixes: e0efd5be63e8 ("cpufreq: intel_pstate: Add HWP boost utility and sched util hooks") Reported-by: Francisco Jerez Cc: 4.18+ # 4.18+: 3da97d4db8ee cpufreq: intel_pstate: Rearrange ... Signed-off-by: Rafael J. Wysocki Reviewed-by: Francisco Jerez Signed-off-by: Sasha Levin

cpufreq: intel_pstate: Fix cpuinfo_max_freq when MSR_TURBO_RATIO_LIMIT is 0

2020-08-26T08:40:56Z

[ Upstream commit 4daca379c703ff55edc065e8e5173dcfeecf0148 ] The MSR_TURBO_RATIO_LIMIT can be 0. This is not an error. User can update this MSR via BIOS settings on some systems or can use msr tools to update. Also some systems boot with value = 0. This results in display of cpufreq/cpuinfo_max_freq wrong. This value will be equal to cpufreq/base_frequency, even though turbo is enabled. But platform will still function normally in HWP mode as we get max 1-core frequency from the MSR_HWP_CAPABILITIES. This MSR is already used to calculate cpu->pstate.turbo_freq, which is used for to set policy->cpuinfo.max_freq. But some other places cpu->pstate.turbo_pstate is used. For example to set policy->max. To fix this, also update cpu->pstate.turbo_pstate when updating cpu->pstate.turbo_freq. Signed-off-by: Srinivas Pandruvada Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

cpufreq: intel_pstate: Only mention the BIOS disabling turbo mode once

2020-05-20T06:20:14Z

[ Upstream commit 8c539776ac83c0857395e1ccc9c6b516521a2d32 ] Make a note of the first time we discover the turbo mode has been disabled by the BIOS, as otherwise we complain every time we try to update the mode. Signed-off-by: Chris Wilson Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

cpufreq: Avoid creating excessively large stack frames

2020-02-11T12:35:25Z

commit 1e4f63aecb53e48468661e922fc2fa3b83e55722 upstream. In the process of modifying a cpufreq policy, the cpufreq core makes a copy of it including all of the internals which is stored on the CPU stack. Because struct cpufreq_policy is relatively large, this may cause the size of the stack frame to exceed the 2 KB limit and so the GCC complains when -Wframe-larger-than= is used. In fact, it is not necessary to copy the entire policy structure in order to modify it, however. First, because cpufreq_set_policy() obtains the min and max policy limits from frequency QoS now, it is not necessary to pass the limits to it from the callers. The only things that need to be passed to it from there are the new governor pointer or (if there is a built-in governor in the driver) the "policy" value representing the governor choice. They both can be passed as individual arguments, though, so make cpufreq_set_policy() take them this way and rework its callers accordingly. This avoids making copies of cpufreq policies in the callers of cpufreq_set_policy(). Second, cpufreq_set_policy() still needs to pass the new policy data to the ->verify() callback of the cpufreq driver whose task is to sanitize the min and max policy limits. It still does not need to make a full copy of struct cpufreq_policy for this purpose, but it needs to pass a few items from it to the driver in case they are needed (different drivers have different needs in that respect and all of them have to be covered). For this reason, introduce struct cpufreq_policy_data to hold copies of the members of struct cpufreq_policy used by the existing ->verify() driver callbacks and pass a pointer to a temporary structure of that type to ->verify() (instead of passing a pointer to full struct cpufreq_policy to it). While at it, notice that intel_pstate and longrun don't really need to verify the "policy" value in struct cpufreq_policy, so drop those check from them to avoid copying "policy" into struct cpufreq_policy_data (which allows it to be slightly smaller). Also while at it fix up white space in a couple of places and make cpufreq_set_policy() static (as it can be so). Fixes: 3000ce3c52f8 ("cpufreq: Use per-policy frequency QoS") Link: https://lore.kernel.org/linux-pm/CAMuHMdX6-jb1W8uC2_237m8ctCpsnGp=JCxqt8pCWVqNXHmkVg@mail.gmail.com Reported-by: kbuild test robot Reported-by: Geert Uytterhoeven Cc: 5.4+ # 5.4+ Signed-off-by: Rafael J. Wysocki Acked-by: Viresh Kumar Signed-off-by: Greg Kroah-Hartman

cpufreq: intel_pstate: Fix invalid EPB setting

2019-11-08T10:29:58Z

The max value of EPB can only be 0x0F. Attempting to set more than that triggers an "unchecked MSR access error" warning which happens in intel_pstate_hwp_force_min_perf() called via cpufreq stop_cpu(). However, it is not even necessary to touch the EPB from intel_pstate, because it is restored on every CPU online by the intel_epb.c code, so let that code do the right thing and drop the redundant (and incorrect) EPB update from intel_pstate. Fixes: af3b7379e2d70 ("cpufreq: intel_pstate: Force HWP min perf before offline") Reported-by: Qian Cai Cc: 5.2+ # 5.2+ Signed-off-by: Srinivas Pandruvada [ rjw: Changelog ] Signed-off-by: Rafael J. Wysocki