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/dax/hmem/device.c | 103 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 103 insertions(+) create mode 100644 drivers/dax/hmem/device.c (limited to 'drivers/dax/hmem/device.c') diff --git a/drivers/dax/hmem/device.c b/drivers/dax/hmem/device.c new file mode 100644 index 000000000..d70359b43 --- /dev/null +++ b/drivers/dax/hmem/device.c @@ -0,0 +1,103 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include +#include "../bus.h" + +static bool nohmem; +module_param_named(disable, nohmem, bool, 0444); + +static bool platform_initialized; +static DEFINE_MUTEX(hmem_resource_lock); +static struct resource hmem_active = { + .name = "HMEM devices", + .start = 0, + .end = -1, + .flags = IORESOURCE_MEM, +}; + +int walk_hmem_resources(struct device *host, walk_hmem_fn fn) +{ + struct resource *res; + int rc = 0; + + mutex_lock(&hmem_resource_lock); + for (res = hmem_active.child; res; res = res->sibling) { + rc = fn(host, (int) res->desc, res); + if (rc) + break; + } + mutex_unlock(&hmem_resource_lock); + return rc; +} +EXPORT_SYMBOL_GPL(walk_hmem_resources); + +static void hmem_work(struct work_struct *work) +{ + /* place holder until dax_hmem driver attaches */ +} + +static struct hmem_platform_device hmem_platform = { + .pdev = { + .name = "hmem_platform", + .id = 0, + }, + .work = __WORK_INITIALIZER(hmem_platform.work, hmem_work), +}; + +static void __hmem_register_resource(int target_nid, struct resource *res) +{ + struct resource *new; + int rc; + + new = __request_region(&hmem_active, res->start, resource_size(res), "", + 0); + if (!new) { + pr_debug("hmem range %pr already active\n", res); + return; + } + + new->desc = target_nid; + + if (platform_initialized) + return; + + rc = platform_device_register(&hmem_platform.pdev); + if (rc) { + pr_err_once("failed to register device-dax hmem_platform device\n"); + return; + } + + platform_initialized = true; +} + +void hmem_register_resource(int target_nid, struct resource *res) +{ + if (nohmem) + return; + + mutex_lock(&hmem_resource_lock); + __hmem_register_resource(target_nid, res); + mutex_unlock(&hmem_resource_lock); +} + +static __init int hmem_register_one(struct resource *res, void *data) +{ + hmem_register_resource(phys_to_target_node(res->start), res); + + return 0; +} + +static __init int hmem_init(void) +{ + walk_soft_reserve_res(0, -1, NULL, hmem_register_one); + return 0; +} + +/* + * As this is a fallback for address ranges unclaimed by the ACPI HMAT + * parsing it must be at an initcall level greater than hmat_init(). + */ +device_initcall(hmem_init); -- cgit v1.3.1