kernel.git/drivers/acpi/cppc_acpi.c, branch linux-6.17.y

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

2025-11-24T09:37:33Z

[ 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

2025-11-24T09:37:32Z

[ 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

2025-11-24T09:37:32Z

[ 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

2025-06-10T18:52:50Z

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

ACPI: CPPC: Add three functions related to autonomous selection

2025-04-30T20:01:31Z

cppc_set_epp() - write energy performance preference register value, based on ACPI 6.5, s8.4.6.1.7 cppc_get_auto_act_window() - read autonomous activity window register value, based on ACPI 6.5, s8.4.6.1.6 cppc_set_auto_act_window() - write autonomous activity window register value, based on ACPI 6.5, s8.4.6.1.6 Reviewed-by: Pierre Gondois Signed-off-by: Lifeng Zheng Reviewed-by: Mario Limonciello Link: https://patch.msgid.link/20250411093855.982491-9-zhenglifeng1@huawei.com Signed-off-by: Rafael J. Wysocki

ACPI: CPPC: Modify cppc_get_auto_sel_caps() to cppc_get_auto_sel()

2025-04-30T20:01:31Z

Modify cppc_get_auto_sel_caps() to cppc_get_auto_sel(). Using a cppc_perf_caps to carry the value is unnecessary. Add a check to ensure the pointer 'enable' is not null. Reviewed-by: Pierre Gondois Signed-off-by: Lifeng Zheng Reviewed-by: Mario Limonciello Link: https://patch.msgid.link/20250411093855.982491-8-zhenglifeng1@huawei.com Signed-off-by: Rafael J. Wysocki

ACPI: CPPC: Refactor register value get and set ABIs

2025-04-30T20:01:31Z

Refactor register value get and set ABIs by using cppc_get_reg_val(), cppc_set_reg_val() and CPPC_REG_VAL_READ(). Reviewed-by: Pierre Gondois Signed-off-by: Lifeng Zheng Reviewed-by: Mario Limonciello Link: https://patch.msgid.link/20250411093855.982491-7-zhenglifeng1@huawei.com Signed-off-by: Rafael J. Wysocki

ACPI: CPPC: Add cppc_set_reg_val()

2025-04-30T20:01:30Z

Add cppc_set_reg_val() as a generic function for setting CPPC register values, with this features: 1. Check register. If a register is writeable, it must be a buffer and can not be null. 2. Extract the operations if register is in PCC out as cppc_set_reg_val_in_pcc(). This function can be used to reduce some existing code duplication. Reviewed-by: Pierre Gondois Signed-off-by: Lifeng Zheng Reviewed-by: Mario Limonciello Link: https://patch.msgid.link/20250411093855.982491-6-zhenglifeng1@huawei.com Signed-off-by: Rafael J. Wysocki

ACPI: CPPC: Extract cppc_get_reg_val_in_pcc()

2025-04-30T20:01:30Z

Extract the operations if register is in pcc out from cppc_get_reg_val() as cppc_get_reg_val_in_pcc(). Reviewed-by: Pierre Gondois Signed-off-by: Lifeng Zheng Reviewed-by: Mario Limonciello Link: https://patch.msgid.link/20250411093855.982491-5-zhenglifeng1@huawei.com Signed-off-by: Rafael J. Wysocki

ACPI: CPPC: Rename cppc_get_perf() to cppc_get_reg_val()

2025-04-30T20:01:30Z

Rename cppc_get_perf() to cppc_get_reg_val() as a generic function to read CPPC registers. Reviewed-by: Pierre Gondois Signed-off-by: Lifeng Zheng Reviewed-by: Mario Limonciello Link: https://patch.msgid.link/20250411093855.982491-4-zhenglifeng1@huawei.com Signed-off-by: Rafael J. Wysocki