From 27600805e62f800bacf990354632eae4e487d34c Mon Sep 17 00:00:00 2001 From: Yazen Ghannam Date: Thu, 3 Sep 2026 10:43:25 -0500 Subject: x86/amd_node: Fix PCI device reference counting in amd_smn_init() The local "root" pointer is a temporary variable used during the device search. Therefore, refcount related to the search iterators should be cleaned up after the search is complete. Use the __free() cleanup macro to ensure the refcount is decremented when the temporary pointer goes out of scope. Additionally, increment the refcount when caching a root pointer. This ensures the in-use refcount is separate from the temporary search refcounting. Finally, drop the redundant "root = NULL" before the second search loop. The pci_get_class() iterator always decrements the refcount of its "from" argument, so the first loop can only fall through with "root" already NULL. Fixes: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching") Closes: https://sashiko.dev/#/patchset/20260806160159.230453-1-jason.andryuk%40amd.com Reported-by: Sashiko Assisted-by: LLM Signed-off-by: Yazen Ghannam Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Mario Limonciello (AMD) Cc: Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com --- Documentation/ABI/testing/amdpmf-interface | 73 ++++++++++++++++++++++++++++++ 1 file changed, 73 insertions(+) create mode 100644 Documentation/ABI/testing/amdpmf-interface (limited to 'Documentation/ABI/testing/amdpmf-interface') diff --git a/Documentation/ABI/testing/amdpmf-interface b/Documentation/ABI/testing/amdpmf-interface new file mode 100644 index 000000000..625f90a01 --- /dev/null +++ b/Documentation/ABI/testing/amdpmf-interface @@ -0,0 +1,73 @@ +What: /dev/amdpmf_interface +Date: June 2026 +KernelVersion: 7.2 +Contact: Shyam Sundar S K +Description: + The AMD Platform Management Framework (PMF) util layer exposes a + minimal user-space interface via a character device for feature + discovery and metrics monitoring. + + When CONFIG_AMD_PMF_UTIL_SUPPORT is enabled, the driver creates + a character device: + + ====================== + /dev/amdpmf_interface + ====================== + + The interface supports a single ioctl: + + ============================ ======================================= + IOCTL Usage + IOCTL_AMD_PMF_POPULATE_DATA User passes a struct amd_pmf_info with + the size field set to sizeof(struct + amd_pmf_info). The driver returns all + available metrics and feature status + in the structure. + ============================ ======================================= + + struct amd_pmf_info layout: + + ======================= ========== ================================ + Field Type Description + size __u64 Structure size for versioning + features_supported __u32 Bitmask of supported features + platform_type __u32 Platform form factor orientation + power_source __u32 AC/DC power source + laptop_placement __u32 Device placement state + lid_state __u32 Lid open/closed status + user_presence __u32 User presence detection + slider_position __u32 Current power slider position + skin_temp __s32 Skin temperature (centidegrees) + gfx_busy __u32 Graphics workload percentage + ambient_light __s32 Ambient light sensor reading + avg_c0_residency __u32 Average C0 state residency + max_c0_residency __u32 Maximum C0 state residency + socket_power __u32 Socket power consumption + bios_input[10] __u32 Custom BIOS input parameters + bios_output[10] __u32 Custom BIOS output parameters + ======================= ========== ================================ + + Feature Support Flags (features_supported bitmask): + + ===================================== ==== ============================= + Flag Bit Description + AMD_PMF_FEAT_AUTO_MODE 0 Auto Mode feature support + AMD_PMF_FEAT_STATIC_POWER_SLIDER 1 Static Power Slider support + AMD_PMF_FEAT_POLICY_BUILDER 2 Policy Builder (Smart PC) + AMD_PMF_FEAT_DYNAMIC_POWER_SLIDER_AC 3 Dynamic slider on AC + AMD_PMF_FEAT_DYNAMIC_POWER_SLIDER_DC 4 Dynamic slider on DC + ===================================== ==== ============================= + + Return codes: + + ============= ============================================================ + Return code Description + 0 Success + EINVAL Invalid size or parameter + EFAULT copy_to_user/copy_from_user failures + ENODEV PMF device not available + ENOTTY Unknown ioctl command + ============= ============================================================ + + User-space tools integrating with AMD PMF to discover capabilities and + monitor real-time metrics for thermal and power management validation. -- cgit v1.3.1