kernel/linux.git/drivers/cpufreq/cppc_cpufreq.c, branch v6.6.132

cpufreq: CPPC: Avoid using CPUFREQ_ETERNAL as transition delay

2025-10-23T14:16:26+00:00

[ Upstream commit f965d111e68f4a993cc44d487d416e3d954eea11 ] If cppc_get_transition_latency() returns CPUFREQ_ETERNAL to indicate a failure to retrieve the transition latency value from the platform firmware, the CPPC cpufreq driver will use that value (converted to microseconds) as the policy transition delay, but it is way too large for any practical use. Address this by making the driver use the cpufreq's default transition latency value (in microseconds) as the transition delay if CPUFREQ_ETERNAL is returned by cppc_get_transition_latency(). Fixes: d4f3388afd48 ("cpufreq / CPPC: Set platform specific transition_delay_us") Cc: 5.19+ # 5.19 Signed-off-by: Rafael J. Wysocki Reviewed-by: Mario Limonciello (AMD) Reviewed-by: Jie Zhan Acked-by: Viresh Kumar Reviewed-by: Qais Yousef [ added CPUFREQ_DEFAULT_TRANSITION_LATENCY_NS definition to include/linux/cpufreq.h ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

cpufreq: CPPC: Mark driver with NEED_UPDATE_LIMITS flag

2025-08-28T14:28:16+00:00

[ Upstream commit 0a1416a49e63c320f6e6c1c8d07e1b58c0d4a3f3 ] AMU counters on certain CPPC-based platforms tend to yield inaccurate delivered performance measurements on systems that are idle/mostly idle. This results in an inaccurate frequency being stored by cpufreq in its policy structure when the CPU is brought online. [1] Consequently, if the userspace governor tries to set the frequency to a new value, there is a possibility that it would be the erroneous value stored earlier. In such a scenario, cpufreq would assume that the requested frequency has already been set and return early, resulting in the correct/new frequency request never making it to the hardware. Since the operating frequency is liable to this sort of inconsistency, mark the CPPC driver with CPUFREQ_NEED_UPDATE_LIMITS so that it is always invoked when a target frequency update is requested. Link: https://lore.kernel.org/linux-pm/20250619000925.415528-3-pmalani@google.com/ [1] Suggested-by: Rafael J. Wysocki Signed-off-by: Prashant Malani Acked-by: Viresh Kumar Link: https://patch.msgid.link/20250722055611.130574-2-pmalani@google.com Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

cpufreq: cppc: Fix invalid return value in .get() callback

2025-05-02T05:50:42+00:00

[ Upstream commit 2b8e6b58889c672e1ae3601d9b2b070be4dc2fbc ] Returning a negative error code in a function with an unsigned return type is a pretty bad idea. It is probably worse when the justification for the change is "our static analisys tool found it". Fixes: cf7de25878a1 ("cppc_cpufreq: Fix possible null pointer dereference") Signed-off-by: Marc Zyngier Cc: "Rafael J. Wysocki" Cc: Viresh Kumar Reviewed-by: Lifeng Zheng Signed-off-by: Viresh Kumar Signed-off-by: Sasha Levin

cpufreq: CPPC: Fix wrong return value in cppc_get_cpu_power()

2024-12-09T09:32:20+00:00

[ Upstream commit b51eb0874d8170028434fbd259e80b78ed9b8eca ] cppc_get_cpu_power() return 0 if the policy is NULL. Then in em_create_perf_table(), the later zero check for power is not valid as power is uninitialized. As Quentin pointed out, kernel energy model core check the return value of active_power() first, so if the callback failed it should tell the core. So return -EINVAL to fix it. Fixes: a78e72075642 ("cpufreq: CPPC: Fix possible null-ptr-deref for cpufreq_cpu_get_raw()") Signed-off-by: Jinjie Ruan Suggested-by: Quentin Perret Signed-off-by: Viresh Kumar Signed-off-by: Sasha Levin

cpufreq: CPPC: Fix wrong return value in cppc_get_cpu_cost()

2024-12-09T09:32:20+00:00

[ Upstream commit be392aa80f1e5b0b65ccc2a540b9304fefcfe3d8 ] cppc_get_cpu_cost() return 0 if the policy is NULL. Then in em_compute_costs(), the later zero check for cost is not valid as cost is uninitialized. As Quentin pointed out, kernel energy model core check the return value of get_cost() first, so if the callback failed it should tell the core. Return -EINVAL to fix it. Fixes: 1a1374bb8c59 ("cpufreq: CPPC: Fix possible null-ptr-deref for cppc_get_cpu_cost()") Reported-by: Dan Carpenter Closes: https://lore.kernel.org/all/c4765377-7830-44c2-84fa-706b6e304e10@stanley.mountain/ Signed-off-by: Jinjie Ruan Suggested-by: Quentin Perret Signed-off-by: Viresh Kumar Signed-off-by: Sasha Levin

cpufreq: CPPC: Fix possible null-ptr-deref for cppc_get_cpu_cost()

2024-12-09T09:32:15+00:00

[ Upstream commit 1a1374bb8c5926674973d849feed500bc61ad535 ] cpufreq_cpu_get_raw() may return NULL if the cpu is not in policy->cpus cpu mask and it will cause null pointer dereference, so check NULL for cppc_get_cpu_cost(). Fixes: 740fcdc2c20e ("cpufreq: CPPC: Register EM based on efficiency class information") Signed-off-by: Jinjie Ruan Signed-off-by: Viresh Kumar Signed-off-by: Sasha Levin

cpufreq: CPPC: Fix possible null-ptr-deref for cpufreq_cpu_get_raw()

2024-12-09T09:32:15+00:00

[ Upstream commit a78e7207564258db6e373e86294a85f9d646d35a ] cpufreq_cpu_get_raw() may return NULL if the cpu is not in policy->cpus cpu mask and it will cause null pointer dereference. Fixes: 740fcdc2c20e ("cpufreq: CPPC: Register EM based on efficiency class information") Signed-off-by: Jinjie Ruan Signed-off-by: Viresh Kumar Signed-off-by: Sasha Levin

cppc_cpufreq: Use desired perf if feedback ctrs are 0 or unchanged

2024-12-09T09:32:12+00:00

[ Upstream commit c47195631960b626058c335aec31f186fa854f97 ] The CPPC performance feedback counters could be 0 or unchanged when the target cpu is in a low-power idle state, e.g. power-gated or clock-gated. When the counters are 0, cppc_cpufreq_get_rate() returns 0 KHz, which makes cpufreq_online() get a false error and fail to generate a cpufreq policy. When the counters are unchanged, the existing cppc_perf_from_fbctrs() returns a cached desired perf, but some platforms may update the real frequency back to the desired perf reg. For the above cases in cppc_cpufreq_get_rate(), get the latest desired perf from the CPPC reg to reflect the frequency because some platforms may update the actual frequency back there; if failed, use the cached desired perf. Fixes: 6a4fec4f6d30 ("cpufreq: cppc: cppc_cpufreq_get_rate() returns zero in all error cases.") Signed-off-by: Jie Zhan Reviewed-by: Zeng Heng Reviewed-by: Ionela Voinescu Reviewed-by: Huisong Li Signed-off-by: Viresh Kumar Signed-off-by: Sasha Levin

cpufreq/cppc: Move and rename cppc_cpufreq_{perf_to_khz|khz_to_perf}()

2024-11-01T00:58:32+00:00

[ Upstream commit 50b813b147e9eb6546a1fc49d4e703e6d23691f2 ] Move and rename cppc_cpufreq_perf_to_khz() and cppc_cpufreq_khz_to_perf() to use them outside cppc_cpufreq in topology_init_cpu_capacity_cppc(). Modify the interface to use struct cppc_perf_caps *caps instead of struct cppc_cpudata *cpu_data as we only use the fields of cppc_perf_caps. cppc_cpufreq was converting the lowest and nominal freq from MHz to kHz before using them. We move this conversion inside cppc_perf_to_khz and cppc_khz_to_perf to make them generic and usable outside cppc_cpufreq. No functional change Signed-off-by: Vincent Guittot Signed-off-by: Ingo Molnar Tested-by: Pierre Gondois Acked-by: Rafael J. Wysocki Acked-by: Viresh Kumar Link: https://lore.kernel.org/r/20231211104855.558096-6-vincent.guittot@linaro.org Stable-dep-of: d93df29bdab1 ("cpufreq: CPPC: fix perf_to_khz/khz_to_perf conversion exception") Signed-off-by: Sasha Levin

cppc_cpufreq: Fix possible null pointer dereference

2024-06-12T09:11:42+00:00

[ Upstream commit cf7de25878a1f4508c69dc9f6819c21ba177dbfe ] cppc_cpufreq_get_rate() and hisi_cppc_cpufreq_get_rate() can be called from different places with various parameters. So cpufreq_cpu_get() can return null as 'policy' in some circumstances. Fix this bug by adding null return check. Found by Linux Verification Center (linuxtesting.org) with SVACE. Fixes: a28b2bfc099c ("cppc_cpufreq: replace per-cpu data array with a list") Signed-off-by: Aleksandr Mishin Signed-off-by: Viresh Kumar Signed-off-by: Sasha Levin