linux-stable.git/drivers/cpufreq/cppc_cpufreq.c, branch v6.1.151 Linux kernel stable tree cpufreq: CPPC: Mark driver with NEED_UPDATE_LIMITS flag 2025-08-28T14:25:52+00:00 Prashant Malani pmalani@google.com 2025-07-22T05:55:40+00:00 ef690c2f2744f45201dfa07e3c5083c91706b949 [ 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 <rafael.j.wysocki@intel.com> Signed-off-by: Prashant Malani <pmalani@google.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Link: https://patch.msgid.link/20250722055611.130574-2-pmalani@google.com Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ 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 <rafael.j.wysocki@intel.com>
Signed-off-by: Prashant Malani <pmalani@google.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://patch.msgid.link/20250722055611.130574-2-pmalani@google.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
cpufreq: cppc: Fix invalid return value in .get() callback 2025-05-02T05:46:54+00:00 Marc Zyngier maz@kernel.org 2025-04-13T10:11:42+00:00 a252684ea1c9da830a1ee2c816d4e3b4d6cd5bfd [ 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 <maz@kernel.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Viresh Kumar <viresh.kumar@linaro.org> Reviewed-by: Lifeng Zheng <zhenglifeng1@huawei.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ 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 <maz@kernel.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Lifeng Zheng <zhenglifeng1@huawei.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
cpufreq: CPPC: Fix wrong return value in cppc_get_cpu_power() 2024-12-14T18:53:41+00:00 Jinjie Ruan ruanjinjie@huawei.com 2024-11-06T01:01:11+00:00 678098cef6459206ac0375bc5fed089db0bdbe43 [ 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 <ruanjinjie@huawei.com> Suggested-by: Quentin Perret <qperret@google.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ 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 <ruanjinjie@huawei.com>
Suggested-by: Quentin Perret <qperret@google.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
cpufreq: CPPC: Fix wrong return value in cppc_get_cpu_cost() 2024-12-14T18:53:41+00:00 Jinjie Ruan ruanjinjie@huawei.com 2024-11-06T01:12:38+00:00 8ef0b11af70799f96588c2aca36fff8d5ce25c7b [ 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 <dan.carpenter@linaro.org> Closes: https://lore.kernel.org/all/c4765377-7830-44c2-84fa-706b6e304e10@stanley.mountain/ Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Suggested-by: Quentin Perret <qperret@google.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ 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 <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/all/c4765377-7830-44c2-84fa-706b6e304e10@stanley.mountain/
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Suggested-by: Quentin Perret <qperret@google.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
cpufreq: CPPC: Fix possible null-ptr-deref for cppc_get_cpu_cost() 2024-12-14T18:53:38+00:00 Jinjie Ruan ruanjinjie@huawei.com 2024-10-30T08:24:49+00:00 1975b481f644f8f841d9c188e3c214fce187f18b [ 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 <ruanjinjie@huawei.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ 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 <ruanjinjie@huawei.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
cpufreq: CPPC: Fix possible null-ptr-deref for cpufreq_cpu_get_raw() 2024-12-14T18:53:37+00:00 Jinjie Ruan ruanjinjie@huawei.com 2024-10-30T01:20:19+00:00 a357b63fd21e4b2791008c2175ba7a8c235ebce1 [ 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 <ruanjinjie@huawei.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ 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 <ruanjinjie@huawei.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
cpufreq/cppc: Move and rename cppc_cpufreq_{perf_to_khz|khz_to_perf}() 2024-11-01T00:56:05+00:00 Vincent Guittot vincent.guittot@linaro.org 2023-12-11T10:48:53+00:00 ff2a9c4029046a1b4bc64f47c7d248c056ba61f4 [ 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 <vincent.guittot@linaro.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Pierre Gondois <pierre.gondois@arm.com> Acked-by: Rafael J. Wysocki <rafael@kernel.org> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> 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 <sashal@kernel.org> 
[ 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 <vincent.guittot@linaro.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Pierre Gondois <pierre.gondois@arm.com>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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 <sashal@kernel.org>
cppc_cpufreq: Fix possible null pointer dereference 2024-06-12T09:03:12+00:00 Aleksandr Mishin amishin@t-argos.ru 2024-04-08T09:35:36+00:00 769c4f355b7962895205b86ad35617873feef9a5 [ 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 <amishin@t-argos.ru> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ 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 <amishin@t-argos.ru>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
cpufreq: CPPC: Add u64 casts to avoid overflowing 2023-02-01T07:34:28+00:00 Pierre Gondois pierre.gondois@arm.com 2022-12-20T10:12:25+00:00 7d596bbc66a52ff2c7a83d7e0ee840cb07e2a045 [ Upstream commit f5f94b9c8b805d87ff185caf9779c3a4d07819e3 ] The fields of the _CPC object are unsigned 32-bits values. To avoid overflows while using _CPC's values, add 'u64' casts. Signed-off-by: Pierre Gondois <pierre.gondois@arm.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit f5f94b9c8b805d87ff185caf9779c3a4d07819e3 ]

The fields of the _CPC object are unsigned 32-bits values.
To avoid overflows while using _CPC's values, add 'u64' casts.

Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
ACPI: CPPC: Disable FIE if registers in PCC regions 2022-09-24T16:43:46+00:00 Jeremy Linton jeremy.linton@arm.com 2022-09-12T20:37:22+00:00 ae2df912d1a557a3548be83da20851ac55f42ab3 PCC regions utilize a mailbox to set/retrieve register values used by the CPPC code. This is fine as long as the operations are infrequent. With the FIE code enabled though the overhead can range from 2-11% of system CPU overhead (ex: as measured by top) on Arm based machines. So, before enabling FIE assure none of the registers used by cppc_get_perf_ctrs() are in the PCC region. Finally, add a module parameter which can override the PCC region detection at boot or module reload. Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Reviewed-by: Ionela Voinescu <ionela.voinescu@arm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 
PCC regions utilize a mailbox to set/retrieve register values used by
the CPPC code. This is fine as long as the operations are
infrequent. With the FIE code enabled though the overhead can range
from 2-11% of system CPU overhead (ex: as measured by top) on Arm
based machines.

So, before enabling FIE assure none of the registers used by
cppc_get_perf_ctrs() are in the PCC region. Finally, add a module
parameter which can override the PCC region detection at boot or
module reload.

Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Ionela Voinescu <ionela.voinescu@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>