kernel/linux.git/drivers/acpi/cppc_acpi.c, branch v6.6.132

ACPI: CPPC: Fix remaining for_each_possible_cpu() to use online CPUs

2026-03-04T12:20:15+00:00

[ Upstream commit 56eb0c0ed345da7815274aa821a8546a073d7e97 ] per_cpu(cpc_desc_ptr, cpu) object is initialized for only the online CPUs via acpi_soft_cpu_online() --> __acpi_processor_start() --> acpi_cppc_processor_probe(). However, send_pcc_cmd() and acpi_get_psd_map() still iterate over all possible CPUs. In acpi_get_psd_map(), encountering an offline CPU returns -EFAULT, causing cppc_cpufreq initialization to fail. This breaks systems booted with "nosmt" or "nosmt=force". Fix by using for_each_online_cpu() in both functions. Fixes: 80b8286aeec0 ("ACPI / CPPC: support for batching CPPC requests") Signed-off-by: Sean V Kelley Link: https://patch.msgid.link/20260211212254.30190-1-skelley@nvidia.com Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

ACPI: CPPC: Fix missing PCC check for guaranteed_perf

2026-01-11T14:21:50+00:00

commit 6ea3a44cef28add2d93b1ef119d84886cb1e3c9b upstream. The current implementation overlooks the 'guaranteed_perf' register in this check. If the Guaranteed Performance register is located in the PCC subspace, the function currently attempts to read it without acquiring the lock and without sending the CMD_READ doorbell to the firmware. This can result in reading stale data. Fixes: 29523f095397 ("ACPI / CPPC: Add support for guaranteed performance") Signed-off-by: Pengjie Zhang Cc: 4.20+ # 4.20+ [ rjw: Subject and changelog edits ] Link: https://patch.msgid.link/20251210132227.1988380-1-zhangpengjie2@huawei.com Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

ACPI: CPPC: Limit perf ctrs in PCC check only to online CPUs

2025-11-24T09:30:01+00:00

[ Upstream commit 0fce75870666b46b700cfbd3216380b422f975da ] per_cpu(cpc_desc_ptr, cpu) object is initialized for only the online CPU via acpi_soft_cpu_online() --> __acpi_processor_start() --> acpi_cppc_processor_probe(). However the function cppc_perf_ctrs_in_pcc() checks if the CPPC perf-ctrs are in a PCC region for all the present CPUs, which breaks when the kernel is booted with "nosmt=force". Hence, limit the check only to the online CPUs. Fixes: ae2df912d1a5 ("ACPI: CPPC: Disable FIE if registers in PCC regions") Reviewed-by: "Mario Limonciello (AMD) (kernel.org)" Signed-off-by: Gautham R. Shenoy Link: https://patch.msgid.link/20251107074145.2340-5-gautham.shenoy@amd.com Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

ACPI: CPPC: Perform fast check switch only for online CPUs

2025-11-24T09:30:01+00:00

[ Upstream commit 8821c8e80a65bc4eb73daf63b34aac6b8ad69461 ] per_cpu(cpc_desc_ptr, cpu) object is initialized for only the online CPUs via acpi_soft_cpu_online() --> __acpi_processor_start() --> acpi_cppc_processor_probe(). However the function cppc_allow_fast_switch() checks for the validity of the _CPC object for all the present CPUs. This breaks when the kernel is booted with "nosmt=force". Check fast_switch capability only on online CPUs Fixes: 15eece6c5b05 ("ACPI: CPPC: Fix NULL pointer dereference when nosmp is used") Reviewed-by: "Mario Limonciello (AMD) (kernel.org)" Signed-off-by: Gautham R. Shenoy Link: https://patch.msgid.link/20251107074145.2340-4-gautham.shenoy@amd.com Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

ACPI: CPPC: Check _CPC validity for only the online CPUs

2025-11-24T09:30:01+00:00

[ Upstream commit 6dd3b8a709a130a4d55c866af9804c81b8486d28 ] per_cpu(cpc_desc_ptr, cpu) object is initialized for only the online CPUs via acpi_soft_cpu_online() --> __acpi_processor_start() --> acpi_cppc_processor_probe(). However the function acpi_cpc_valid() checks for the validity of the _CPC object for all the present CPUs. This breaks when the kernel is booted with "nosmt=force". Hence check the validity of the _CPC objects of only the online CPUs. Fixes: 2aeca6bd0277 ("ACPI: CPPC: Check present CPUs for determining _CPC is valid") Reported-by: Christopher Harris Closes: https://lore.kernel.org/lkml/CAM+eXpdDT7KjLV0AxEwOLkSJ2QtrsvGvjA2cCHvt1d0k2_C4Cw@mail.gmail.com/ Suggested-by: Mario Limonciello Reviewed-by: "Mario Limonciello (AMD) (kernel.org)" Tested-by: Chrisopher Harris Signed-off-by: Gautham R. Shenoy Link: https://patch.msgid.link/20251107074145.2340-3-gautham.shenoy@amd.com Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

ACPI: CPPC: Fix NULL pointer dereference when nosmp is used

2025-06-19T13:28:41+00:00

[ Upstream commit 15eece6c5b05e5f9db0711978c3e3b7f1a2cfe12 ] With nosmp in cmdline, other CPUs are not brought up, leaving their cpc_desc_ptr NULL. CPU0's iteration via for_each_possible_cpu() dereferences these NULL pointers, causing panic. Panic backtrace: [ 0.401123] Unable to handle kernel NULL pointer dereference at virtual address 00000000000000b8 ... [ 0.403255] [] cppc_allow_fast_switch+0x6a/0xd4 ... Kernel panic - not syncing: Attempted to kill init! Fixes: 3cc30dd00a58 ("cpufreq: CPPC: Enable fast_switch") Reported-by: Xu Lu Signed-off-by: Yunhui Cui Link: https://patch.msgid.link/20250604023036.99553-1-cuiyunhui@bytedance.com [ rjw: New subject ] Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

ACPI: CPPC: Fix _CPC register setting issue

2024-12-09T09:31:49+00:00

[ Upstream commit 2388b266c9fcc7c9169ba85c7f9ebe325b7622d7 ] Since commit 60949b7b8054 ("ACPI: CPPC: Fix MASK_VAL() usage"), _CPC registers cannot be changed from 1 to 0. It turns out that there is an extra OR after MASK_VAL_WRITE(), which has already ORed prev_val with the register mask. Remove the extra OR to fix the problem. Fixes: 60949b7b8054 ("ACPI: CPPC: Fix MASK_VAL() usage") Signed-off-by: Lifeng Zheng Link: https://patch.msgid.link/20241113103309.761031-1-zhenglifeng1@huawei.com [ rjw: Subject and changelog edits ] Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

ACPI: CPPC: Make rmw_lock a raw_spin_lock

2024-11-08T15:28:20+00:00

[ Upstream commit 1c10941e34c5fdc0357e46a25bd130d9cf40b925 ] The following BUG was triggered: ============================= [ BUG: Invalid wait context ] 6.12.0-rc2-XXX #406 Not tainted ----------------------------- kworker/1:1/62 is trying to lock: ffffff8801593030 (&cpc_ptr->rmw_lock){+.+.}-{3:3}, at: cpc_write+0xcc/0x370 other info that might help us debug this: context-{5:5} 2 locks held by kworker/1:1/62: #0: ffffff897ef5ec98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2c/0x50 #1: ffffff880154e238 (&sg_policy->update_lock){....}-{2:2}, at: sugov_update_shared+0x3c/0x280 stack backtrace: CPU: 1 UID: 0 PID: 62 Comm: kworker/1:1 Not tainted 6.12.0-rc2-g9654bd3e8806 #406 Workqueue: 0x0 (events) Call trace: dump_backtrace+0xa4/0x130 show_stack+0x20/0x38 dump_stack_lvl+0x90/0xd0 dump_stack+0x18/0x28 __lock_acquire+0x480/0x1ad8 lock_acquire+0x114/0x310 _raw_spin_lock+0x50/0x70 cpc_write+0xcc/0x370 cppc_set_perf+0xa0/0x3a8 cppc_cpufreq_fast_switch+0x40/0xc0 cpufreq_driver_fast_switch+0x4c/0x218 sugov_update_shared+0x234/0x280 update_load_avg+0x6ec/0x7b8 dequeue_entities+0x108/0x830 dequeue_task_fair+0x58/0x408 __schedule+0x4f0/0x1070 schedule+0x54/0x130 worker_thread+0xc0/0x2e8 kthread+0x130/0x148 ret_from_fork+0x10/0x20 sugov_update_shared() locks a raw_spinlock while cpc_write() locks a spinlock. To have a correct wait-type order, update rmw_lock to a raw spinlock and ensure that interrupts will be disabled on the CPU holding it. Fixes: 60949b7b8054 ("ACPI: CPPC: Fix MASK_VAL() usage") Signed-off-by: Pierre Gondois Link: https://patch.msgid.link/20241028125657.1271512-1-pierre.gondois@arm.com [ rjw: Changelog edits ] Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

cpufreq: CPPC: fix perf_to_khz/khz_to_perf conversion exception

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

[ Upstream commit d93df29bdab133b85e94b3c328e7fe26a0ebd56c ] When the nominal_freq recorded by the kernel is equal to the lowest_freq, and the frequency adjustment operation is triggered externally, there is a logic error in cppc_perf_to_khz()/cppc_khz_to_perf(), resulting in perf and khz conversion errors. Fix this by adding a branch processing logic when nominal_freq is equal to lowest_freq. Fixes: ec1c7ad47664 ("cpufreq: CPPC: Fix performance/frequency conversion") Signed-off-by: liwei Acked-by: Viresh Kumar Link: https://patch.msgid.link/20241024022952.2627694-1-liwei728@huawei.com [ rjw: Subject and changelog edits ] Signed-off-by: Rafael J. Wysocki 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