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/nvmem/u-boot-env.c | 99 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 99 insertions(+) create mode 100644 drivers/nvmem/u-boot-env.c (limited to 'drivers/nvmem/u-boot-env.c') diff --git a/drivers/nvmem/u-boot-env.c b/drivers/nvmem/u-boot-env.c new file mode 100644 index 000000000..467b28891 --- /dev/null +++ b/drivers/nvmem/u-boot-env.c @@ -0,0 +1,99 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2022 Rafał Miłecki + */ + +#include +#include +#include +#include +#include +#include + +#include "layouts/u-boot-env.h" + +struct u_boot_env { + struct device *dev; + struct nvmem_device *nvmem; + enum u_boot_env_format format; + + struct mtd_info *mtd; +}; + +static int u_boot_env_read(void *context, unsigned int offset, void *val, + size_t bytes) +{ + struct u_boot_env *priv = context; + struct device *dev = priv->dev; + size_t bytes_read; + int err; + + err = mtd_read(priv->mtd, offset, bytes, &bytes_read, val); + if (err && !mtd_is_bitflip(err)) { + dev_err(dev, "Failed to read from mtd: %d\n", err); + return err; + } + + if (bytes_read != bytes) { + dev_err(dev, "Failed to read %zu bytes\n", bytes); + return -EIO; + } + + return 0; +} + +static int u_boot_env_probe(struct platform_device *pdev) +{ + struct nvmem_config config = { + .name = "u-boot-env", + .reg_read = u_boot_env_read, + }; + struct device *dev = &pdev->dev; + struct device_node *np = dev->of_node; + struct u_boot_env *priv; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + priv->dev = dev; + + priv->format = (uintptr_t)of_device_get_match_data(dev); + + priv->mtd = of_get_mtd_device_by_node(np); + if (IS_ERR(priv->mtd)) { + dev_err_probe(dev, PTR_ERR(priv->mtd), "Failed to get %pOF MTD\n", np); + return PTR_ERR(priv->mtd); + } + + config.dev = dev; + config.priv = priv; + config.size = priv->mtd->size; + + priv->nvmem = devm_nvmem_register(dev, &config); + if (IS_ERR(priv->nvmem)) + return PTR_ERR(priv->nvmem); + + return u_boot_env_parse(dev, priv->nvmem, priv->format); +} + +static const struct of_device_id u_boot_env_of_match_table[] = { + { .compatible = "u-boot,env", .data = (void *)U_BOOT_FORMAT_SINGLE, }, + { .compatible = "u-boot,env-redundant-bool", .data = (void *)U_BOOT_FORMAT_REDUNDANT, }, + { .compatible = "u-boot,env-redundant-count", .data = (void *)U_BOOT_FORMAT_REDUNDANT, }, + { .compatible = "brcm,env", .data = (void *)U_BOOT_FORMAT_BROADCOM, }, + {}, +}; + +static struct platform_driver u_boot_env_driver = { + .probe = u_boot_env_probe, + .driver = { + .name = "u_boot_env", + .of_match_table = u_boot_env_of_match_table, + }, +}; +module_platform_driver(u_boot_env_driver); + +MODULE_AUTHOR("Rafał Miłecki"); +MODULE_DESCRIPTION("U-Boot environment variables support module"); +MODULE_LICENSE("GPL"); +MODULE_DEVICE_TABLE(of, u_boot_env_of_match_table); -- cgit v1.3.1