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 --- drivers/acpi/hed.c | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 90 insertions(+) create mode 100644 drivers/acpi/hed.c (limited to 'drivers/acpi/hed.c') diff --git a/drivers/acpi/hed.c b/drivers/acpi/hed.c new file mode 100644 index 000000000..48562f53d --- /dev/null +++ b/drivers/acpi/hed.c @@ -0,0 +1,90 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * ACPI Hardware Error Device (PNP0C33) Driver + * + * Copyright (C) 2010, Intel Corp. + * Author: Huang Ying + * + * ACPI Hardware Error Device is used to report some hardware errors + * notified via SCI, mainly the corrected errors. + */ + +#include +#include +#include +#include +#include +#include + +static const struct acpi_device_id acpi_hed_ids[] = { + {"PNP0C33", 0}, + {"", 0}, +}; +MODULE_DEVICE_TABLE(acpi, acpi_hed_ids); + +static bool hed_present; + +static BLOCKING_NOTIFIER_HEAD(acpi_hed_notify_list); + +int register_acpi_hed_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_register(&acpi_hed_notify_list, nb); +} +EXPORT_SYMBOL_GPL(register_acpi_hed_notifier); + +void unregister_acpi_hed_notifier(struct notifier_block *nb) +{ + blocking_notifier_chain_unregister(&acpi_hed_notify_list, nb); +} +EXPORT_SYMBOL_GPL(unregister_acpi_hed_notifier); + +/* + * SCI to report hardware error is forwarded to the listeners of HED, + * it is used by HEST Generic Hardware Error Source with notify type + * SCI. + */ +static void acpi_hed_notify(acpi_handle handle, u32 event, void *data) +{ + blocking_notifier_call_chain(&acpi_hed_notify_list, 0, NULL); +} + +static int acpi_hed_probe(struct platform_device *pdev) +{ + int err; + + /* Only one hardware error device */ + if (hed_present) + return -EINVAL; + + err = devm_acpi_install_notify_handler(&pdev->dev, ACPI_DEVICE_NOTIFY, + acpi_hed_notify, NULL); + if (err) + return err; + + hed_present = true; + return 0; +} + +static void acpi_hed_remove(struct platform_device *pdev) +{ + hed_present = false; +} + +static struct platform_driver acpi_hed_driver = { + .probe = acpi_hed_probe, + .remove = acpi_hed_remove, + .driver = { + .name = "acpi-hardware-error-device", + .acpi_match_table = acpi_hed_ids, + }, +}; + +static int __init acpi_hed_driver_init(void) +{ + return platform_driver_register(&acpi_hed_driver); +} +subsys_initcall(acpi_hed_driver_init); + +MODULE_AUTHOR("Huang Ying"); +MODULE_DESCRIPTION("ACPI Hardware Error Device Driver"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1