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2026-03-30PM: EM: Fix NULL pointer dereference when perf domain ID is not foundChangwoo Min
dev_energymodel_nl_get_perf_domains_doit() calls em_perf_domain_get_by_id() but does not check the return value before passing it to __em_nl_get_pd_size(). When a caller supplies a non-existent perf domain ID, em_perf_domain_get_by_id() returns NULL, and __em_nl_get_pd_size() immediately dereferences pd->cpus (struct offset 0x30), causing a NULL pointer dereference. The sister handler dev_energymodel_nl_get_perf_table_doit() already handles this correctly via __em_nl_get_pd_table_id(), which returns NULL and causes the caller to return -EINVAL. Add the same NULL check in the get-perf-domains do handler. Fixes: 380ff27af25e ("PM: EM: Add dump to get-perf-domains in the EM YNL spec") Reported-by: Yi Lai <yi1.lai@linux.intel.com> Closes: https://lore.kernel.org/lkml/aXiySM79UYfk+ytd@ly-workstation/ Signed-off-by: Changwoo Min <changwoo@igalia.com> Cc: 6.19+ <stable@vger.kernel.org> # 6.19+ [ rjw: Subject and changelog edits ] Link: https://patch.msgid.link/20260329073615.649976-1-changwoo@igalia.com Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2026-01-09PM: EM: Add dump to get-perf-domains in the EM YNL specChangwoo Min
Add dump to get-perf-domains, so that a user can fetch either information about a specific performance domain with do or information about all performance domains with dump. Share the reply format of do and dump using perf-domain-attrs, so remove perf-domains. The YNL spec, autogenerated files, and the do implementation are updated, and the dump implementation is added. Suggested-by: Donald Hunter <donald.hunter@gmail.com> Reviewed-by: Lukasz Luba <lukasz.luba@arm.com> Reviewed-by: Donald Hunter <donald.hunter@gmail.com> Signed-off-by: Changwoo Min <changwoo@igalia.com> Link: https://patch.msgid.link/20260108053212.642478-5-changwoo@igalia.com Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2026-01-09PM: EM: Change cpus' type from string to u64 array in the EM YNL specChangwoo Min
Previously, the cpus attribute was a string format which was a "%*pb" stringification of a bitmap. That is not very consumable for a UAPI, so let’s change it to an u64 array of CPU ids. Suggested-by: Donald Hunter <donald.hunter@gmail.com> Reviewed-by: Lukasz Luba <lukasz.luba@arm.com> Reviewed-by: Donald Hunter <donald.hunter@gmail.com> Signed-off-by: Changwoo Min <changwoo@igalia.com> Link: https://patch.msgid.link/20260108053212.642478-4-changwoo@igalia.com Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2026-01-09PM: EM: Rename em.yaml to dev-energymodel.yamlChangwoo Min
The EM YNL specification used many acronyms, including ‘em’, ‘pd’, ‘ps’, etc. While the acronyms are short and convenient, they could be confusing. So, let’s spell them out to be more specific. The following changes were made in the spec. Note that the protocol name cannot exceed GENL_NAMSIZ (16). em -> dev-energymodel pds -> perf-domains pd -> perf-domain pd-id -> perf-domain-id pd-table -> perf-table ps -> perf-state get-pds -> get-perf-domains get-pd-table -> get-perf-table pd-created -> perf-domain-created pd-updated -> perf-domain-updated pd-deleted -> perf-domain-deleted In addition. doc strings were added to the spec. based on the comments in energy_model.h. Two flag attributes (perf-state-flags and perf-domain-flags) were added for easily interpreting the bit flags. Finally, the autogenerated files and em_netlink.c were updated accordingly to reflect the name changes. Suggested-by: Donald Hunter <donald.hunter@gmail.com> Reviewed-by: Lukasz Luba <lukasz.luba@arm.com> Reviewed-by: Donald Hunter <donald.hunter@gmail.com> Signed-off-by: Changwoo Min <changwoo@igalia.com> Link: https://patch.msgid.link/20260108053212.642478-3-changwoo@igalia.com Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2025-10-22PM: EM: Implement em_notify_pd_created/updated()Changwoo Min
Implement two event notifications when a performance domain is created (EM_CMD_PD_CREATED) and updated (EM_CMD_PD_UPDATED). The message format of these two event notifications is the same as EM_CMD_GET_PD_TABLE -- containing the performance domain's ID and its energy model table. Signed-off-by: Changwoo Min <changwoo@igalia.com> Reviewed-by: Lukasz Luba <lukasz.luba@arm.com> Link: https://patch.msgid.link/20251020220914.320832-10-changwoo@igalia.com Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2025-10-22PM: EM: Implement em_notify_pd_deleted()Changwoo Min
Add the event notification infrastructure and implement the event notification for when a performance domain is deleted (EM_CMD_PD_DELETED). The event contains the ID of the performance domain (EM_A_PD_TABLE_PD_ID) so the userspace can identify the changed performance domain for further processing. Signed-off-by: Changwoo Min <changwoo@igalia.com> Reviewed-by: Lukasz Luba <lukasz.luba@arm.com> Link: https://patch.msgid.link/20251020220914.320832-9-changwoo@igalia.com Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2025-10-22PM: EM: Implement em_nl_get_pd_table_doit()Changwoo Min
When a userspace requests EM_CMD_GET_PD_TABLE with an ID of a performance domain, the kernel reports back the energy model table of the specified performance domain. The message format of the response is as follows: EM_A_PD_TABLE_PD_ID (NLA_U32) EM_A_PD_TABLE_PS (NLA_NESTED)* EM_A_PS_PERFORMANCE (NLA_U64) EM_A_PS_FREQUENCY (NLA_U64) EM_A_PS_POWER (NLA_U64) EM_A_PS_COST (NLA_U64) EM_A_PS_FLAGS (NLA_U64) where EM_A_PD_TABLE_PS can be repeated as many times as there are performance states (struct em_perf_state). Signed-off-by: Changwoo Min <changwoo@igalia.com> Reviewed-by: Lukasz Luba <lukasz.luba@arm.com> Link: https://patch.msgid.link/20251020220914.320832-8-changwoo@igalia.com Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2025-10-22PM: EM: Implement em_nl_get_pds_doit()Changwoo Min
When a userspace requests EM_CMD_GET_PDS, the kernel responds with information on all performance domains. The message format of the response is as follows: EM_A_PDS_PD (NLA_NESTED)* EM_A_PD_PD_ID (NLA_U32) EM_A_PD_FLAGS (NLA_U64) EM_A_PD_CPUS (NLA_STRING) where EM_A_PDS_PD can be repeated as many times as there are performance domains, and EM_A_PD_CPUS is a hexadecimal string representing a CPU bitmask. Signed-off-by: Changwoo Min <changwoo@igalia.com> Reviewed-by: Lukasz Luba <lukasz.luba@arm.com> Link: https://patch.msgid.link/20251020220914.320832-7-changwoo@igalia.com Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2025-10-22PM: EM: Add a skeleton code for netlink notificationChangwoo Min
Add a boilerplate code for netlink notification to register the new protocol family. Also, initialize and register the netlink during booting. The initialization is called at the postcore level, which is late enough after the generic netlink is initialized. Finally, update MAINTAINERS to include new files. Signed-off-by: Changwoo Min <changwoo@igalia.com> Reviewed-by: Lukasz Luba <lukasz.luba@arm.com> Link: https://patch.msgid.link/20251020220914.320832-5-changwoo@igalia.com Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>