diff options
Diffstat (limited to 'drivers/firmware/efi')
| -rw-r--r-- | drivers/firmware/efi/Kconfig | 5 | ||||
| -rw-r--r-- | drivers/firmware/efi/Makefile | 1 | ||||
| -rw-r--r-- | drivers/firmware/efi/embedded-firmware.c | 147 |
3 files changed, 153 insertions, 0 deletions
diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig index ecc83e2f032c..613828d3f106 100644 --- a/drivers/firmware/efi/Kconfig +++ b/drivers/firmware/efi/Kconfig @@ -239,6 +239,11 @@ config EFI_DISABLE_PCI_DMA endmenu +config EFI_EMBEDDED_FIRMWARE + bool + depends on EFI + select CRYPTO_LIB_SHA256 + config UEFI_CPER bool diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile index 554d795270d9..256d6121b2b3 100644 --- a/drivers/firmware/efi/Makefile +++ b/drivers/firmware/efi/Makefile @@ -26,6 +26,7 @@ obj-$(CONFIG_EFI_TEST) += test/ obj-$(CONFIG_EFI_DEV_PATH_PARSER) += dev-path-parser.o obj-$(CONFIG_APPLE_PROPERTIES) += apple-properties.o obj-$(CONFIG_EFI_RCI2_TABLE) += rci2-table.o +obj-$(CONFIG_EFI_EMBEDDED_FIRMWARE) += embedded-firmware.o fake_map-y += fake_mem.o fake_map-$(CONFIG_X86) += x86_fake_mem.o diff --git a/drivers/firmware/efi/embedded-firmware.c b/drivers/firmware/efi/embedded-firmware.c new file mode 100644 index 000000000000..1bc9cdae2eed --- /dev/null +++ b/drivers/firmware/efi/embedded-firmware.c @@ -0,0 +1,147 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Support for extracting embedded firmware for peripherals from EFI code, + * + * Copyright (c) 2018 Hans de Goede <hdegoede@redhat.com> + */ + +#include <linux/dmi.h> +#include <linux/efi.h> +#include <linux/efi_embedded_fw.h> +#include <linux/io.h> +#include <linux/slab.h> +#include <linux/types.h> +#include <linux/vmalloc.h> +#include <crypto/sha.h> + +/* Exported for use by lib/test_firmware.c only */ +LIST_HEAD(efi_embedded_fw_list); +EXPORT_SYMBOL_GPL(efi_embedded_fw_list); + +static bool checked_for_fw; + +static const struct dmi_system_id * const embedded_fw_table[] = { + NULL +}; + +/* + * Note the efi_check_for_embedded_firmwares() code currently makes the + * following 2 assumptions. This may needs to be revisited if embedded firmware + * is found where this is not true: + * 1) The firmware is only found in EFI_BOOT_SERVICES_CODE memory segments + * 2) The firmware always starts at an offset which is a multiple of 8 bytes + */ +static int __init efi_check_md_for_embedded_firmware( + efi_memory_desc_t *md, const struct efi_embedded_fw_desc *desc) +{ + struct sha256_state sctx; + struct efi_embedded_fw *fw; + u8 sha256[32]; + u64 i, size; + u8 *map; + + size = md->num_pages << EFI_PAGE_SHIFT; + map = memremap(md->phys_addr, size, MEMREMAP_WB); + if (!map) { + pr_err("Error mapping EFI mem at %#llx\n", md->phys_addr); + return -ENOMEM; + } + + for (i = 0; (i + desc->length) <= size; i += 8) { + if (memcmp(map + i, desc->prefix, EFI_EMBEDDED_FW_PREFIX_LEN)) + continue; + + sha256_init(&sctx); + sha256_update(&sctx, map + i, desc->length); + sha256_final(&sctx, sha256); + if (memcmp(sha256, desc->sha256, 32) == 0) + break; + } + if ((i + desc->length) > size) { + memunmap(map); + return -ENOENT; + } + + pr_info("Found EFI embedded fw '%s'\n", desc->name); + + fw = kmalloc(sizeof(*fw), GFP_KERNEL); + if (!fw) { + memunmap(map); + return -ENOMEM; + } + + fw->data = kmemdup(map + i, desc->length, GFP_KERNEL); + memunmap(map); + if (!fw->data) { + kfree(fw); + return -ENOMEM; + } + + fw->name = desc->name; + fw->length = desc->length; + list_add(&fw->list, &efi_embedded_fw_list); + + return 0; +} + +void __init efi_check_for_embedded_firmwares(void) +{ + const struct efi_embedded_fw_desc *fw_desc; + const struct dmi_system_id *dmi_id; + efi_memory_desc_t *md; + int i, r; + + for (i = 0; embedded_fw_table[i]; i++) { + dmi_id = dmi_first_match(embedded_fw_table[i]); + if (!dmi_id) + continue; + + fw_desc = dmi_id->driver_data; + + /* + * In some drivers the struct driver_data contains may contain + * other driver specific data after the fw_desc struct; and + * the fw_desc struct itself may be empty, skip these. + */ + if (!fw_desc->name) + continue; + + for_each_efi_memory_desc(md) { + if (md->type != EFI_BOOT_SERVICES_CODE) + continue; + + r = efi_check_md_for_embedded_firmware(md, fw_desc); + if (r == 0) + break; + } + } + + checked_for_fw = true; +} + +int efi_get_embedded_fw(const char *name, const u8 **data, size_t *size) +{ + struct efi_embedded_fw *iter, *fw = NULL; + + if (!checked_for_fw) { + pr_warn("Warning %s called while we did not check for embedded fw\n", + __func__); + return -ENOENT; + } + + list_for_each_entry(iter, &efi_embedded_fw_list, list) { + if (strcmp(name, iter->name) == 0) { + fw = iter; + break; + } + } + + if (!fw) + return -ENOENT; + + *data = fw->data; + *size = fw->length; + + return 0; +} +EXPORT_SYMBOL_GPL(efi_get_embedded_fw); |