diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig index c981be17d3c0..893fda48fcdd 100644 --- a/drivers/firmware/efi/Kconfig +++ b/drivers/firmware/efi/Kconfig @@ -133,3 +133,8 @@ endmenu config UEFI_CPER bool + +config EFI_DEV_PATH_PARSER + bool + depends on ACPI + default n diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile index c8a439f6d715..3e91ae31f9d1 100644 --- a/drivers/firmware/efi/Makefile +++ b/drivers/firmware/efi/Makefile @@ -21,6 +21,7 @@ obj-$(CONFIG_EFI_STUB) += libstub/ obj-$(CONFIG_EFI_FAKE_MEMMAP) += fake_mem.o obj-$(CONFIG_EFI_BOOTLOADER_CONTROL) += efibc.o obj-$(CONFIG_EFI_TEST) += test/ +obj-$(CONFIG_EFI_DEV_PATH_PARSER) += dev-path-parser.o arm-obj-$(CONFIG_EFI) := arm-init.o arm-runtime.o obj-$(CONFIG_ARM) += $(arm-obj-y) diff --git a/drivers/firmware/efi/dev-path-parser.c b/drivers/firmware/efi/dev-path-parser.c new file mode 100644 index 000000000000..85d1834ee9b7 --- /dev/null +++ b/drivers/firmware/efi/dev-path-parser.c @@ -0,0 +1,203 @@ +/* + * dev-path-parser.c - EFI Device Path parser + * Copyright (C) 2016 Lukas Wunner + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License (version 2) as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see . + */ + +#include +#include +#include + +struct acpi_hid_uid { + struct acpi_device_id hid[2]; + char uid[11]; /* UINT_MAX + null byte */ +}; + +static int __init match_acpi_dev(struct device *dev, void *data) +{ + struct acpi_hid_uid hid_uid = *(struct acpi_hid_uid *)data; + struct acpi_device *adev = to_acpi_device(dev); + + if (acpi_match_device_ids(adev, hid_uid.hid)) + return 0; + + if (adev->pnp.unique_id) + return !strcmp(adev->pnp.unique_id, hid_uid.uid); + else + return !strcmp("0", hid_uid.uid); +} + +static long __init parse_acpi_path(struct efi_dev_path *node, + struct device *parent, struct device **child) +{ + struct acpi_hid_uid hid_uid = {}; + struct device *phys_dev; + + if (node->length != 12) + return -EINVAL; + + sprintf(hid_uid.hid[0].id, "%c%c%c%04X", + 'A' + ((node->acpi.hid >> 10) & 0x1f) - 1, + 'A' + ((node->acpi.hid >> 5) & 0x1f) - 1, + 'A' + ((node->acpi.hid >> 0) & 0x1f) - 1, + node->acpi.hid >> 16); + sprintf(hid_uid.uid, "%u", node->acpi.uid); + + *child = bus_find_device(&acpi_bus_type, NULL, &hid_uid, + match_acpi_dev); + if (!*child) + return -ENODEV; + + phys_dev = acpi_get_first_physical_node(to_acpi_device(*child)); + if (phys_dev) { + get_device(phys_dev); + put_device(*child); + *child = phys_dev; + } + + return 0; +} + +static int __init match_pci_dev(struct device *dev, void *data) +{ + unsigned int devfn = *(unsigned int *)data; + + return dev_is_pci(dev) && to_pci_dev(dev)->devfn == devfn; +} + +static long __init parse_pci_path(struct efi_dev_path *node, + struct device *parent, struct device **child) +{ + unsigned int devfn; + + if (node->length != 6) + return -EINVAL; + if (!parent) + return -EINVAL; + + devfn = PCI_DEVFN(node->pci.dev, node->pci.fn); + + *child = device_find_child(parent, &devfn, match_pci_dev); + if (!*child) + return -ENODEV; + + return 0; +} + +/* + * Insert parsers for further node types here. + * + * Each parser takes a pointer to the @node and to the @parent (will be NULL + * for the first device path node). If a device corresponding to @node was + * found below @parent, its reference count should be incremented and the + * device returned in @child. + * + * The return value should be 0 on success or a negative int on failure. + * The special return values 0x01 (EFI_DEV_END_INSTANCE) and 0xFF + * (EFI_DEV_END_ENTIRE) signal the end of the device path, only + * parse_end_path() is supposed to return this. + * + * Be sure to validate the node length and contents before commencing the + * search for a device. + */ + +static long __init parse_end_path(struct efi_dev_path *node, + struct device *parent, struct device **child) +{ + if (node->length != 4) + return -EINVAL; + if (node->sub_type != EFI_DEV_END_INSTANCE && + node->sub_type != EFI_DEV_END_ENTIRE) + return -EINVAL; + if (!parent) + return -ENODEV; + + *child = get_device(parent); + return node->sub_type; +} + +/** + * efi_get_device_by_path - find device by EFI Device Path + * @node: EFI Device Path + * @len: maximum length of EFI Device Path in bytes + * + * Parse a series of EFI Device Path nodes at @node and find the corresponding + * device. If the device was found, its reference count is incremented and a + * pointer to it is returned. The caller needs to drop the reference with + * put_device() after use. The @node pointer is updated to point to the + * location immediately after the "End of Hardware Device Path" node. + * + * If another Device Path instance follows, @len is decremented by the number + * of bytes consumed. Otherwise @len is set to %0. + * + * If a Device Path node is malformed or its corresponding device is not found, + * @node is updated to point to this offending node and an ERR_PTR is returned. + * + * If @len is initially %0, the function returns %NULL. Thus, to iterate over + * all instances in a path, the following idiom may be used: + * + * while (!IS_ERR_OR_NULL(dev = efi_get_device_by_path(&node, &len))) { + * // do something with dev + * put_device(dev); + * } + * if (IS_ERR(dev)) + * // report error + * + * Devices can only be found if they're already instantiated. Most buses + * instantiate devices in the "subsys" initcall level, hence the earliest + * initcall level in which this function should be called is "fs". + * + * Returns the device on success or + * %ERR_PTR(-ENODEV) if no device was found, + * %ERR_PTR(-EINVAL) if a node is malformed or exceeds @len, + * %ERR_PTR(-ENOTSUPP) if support for a node type is not yet implemented. + */ +struct device * __init efi_get_device_by_path(struct efi_dev_path **node, + size_t *len) +{ + struct device *parent = NULL, *child; + long ret = 0; + + if (!*len) + return NULL; + + while (!ret) { + if (*len < 4 || *len < (*node)->length) + ret = -EINVAL; + else if ((*node)->type == EFI_DEV_ACPI && + (*node)->sub_type == EFI_DEV_BASIC_ACPI) + ret = parse_acpi_path(*node, parent, &child); + else if ((*node)->type == EFI_DEV_HW && + (*node)->sub_type == EFI_DEV_PCI) + ret = parse_pci_path(*node, parent, &child); + else if (((*node)->type == EFI_DEV_END_PATH || + (*node)->type == EFI_DEV_END_PATH2)) + ret = parse_end_path(*node, parent, &child); + else + ret = -ENOTSUPP; + + put_device(parent); + if (ret < 0) + return ERR_PTR(ret); + + parent = child; + *node = (void *)*node + (*node)->length; + *len -= (*node)->length; + } + + if (ret == EFI_DEV_END_ENTIRE) + *len = 0; + + return child; +} diff --git a/include/linux/efi.h b/include/linux/efi.h index f5a821d9b90c..261767212c47 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -1148,6 +1148,26 @@ struct efi_generic_dev_path { u16 length; } __attribute ((packed)); +struct efi_dev_path { + u8 type; /* can be replaced with unnamed */ + u8 sub_type; /* struct efi_generic_dev_path; */ + u16 length; /* once we've moved to -std=c11 */ + union { + struct { + u32 hid; + u32 uid; + } acpi; + struct { + u8 fn; + u8 dev; + } pci; + }; +} __attribute ((packed)); + +#if IS_ENABLED(CONFIG_EFI_DEV_PATH_PARSER) +struct device *efi_get_device_by_path(struct efi_dev_path **node, size_t *len); +#endif + static inline void memrange_efi_to_native(u64 *addr, u64 *npages) { *npages = PFN_UP(*addr + (*npages<