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107 lines
2.5 KiB
107 lines
2.5 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* efibc: control EFI bootloaders which obey LoaderEntryOneShot var |
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* Copyright (c) 2013-2016, Intel Corporation. |
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*/ |
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#define pr_fmt(fmt) "efibc: " fmt |
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#include <linux/efi.h> |
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#include <linux/module.h> |
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#include <linux/reboot.h> |
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#include <linux/slab.h> |
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static void efibc_str_to_str16(const char *str, efi_char16_t *str16) |
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{ |
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size_t i; |
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for (i = 0; i < strlen(str); i++) |
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str16[i] = str[i]; |
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str16[i] = '\0'; |
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} |
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static int efibc_set_variable(const char *name, const char *value) |
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{ |
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int ret; |
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efi_guid_t guid = LINUX_EFI_LOADER_ENTRY_GUID; |
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struct efivar_entry *entry; |
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size_t size = (strlen(value) + 1) * sizeof(efi_char16_t); |
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if (size > sizeof(entry->var.Data)) { |
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pr_err("value is too large (%zu bytes) for '%s' EFI variable\n", size, name); |
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return -EINVAL; |
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} |
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entry = kmalloc(sizeof(*entry), GFP_KERNEL); |
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if (!entry) { |
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pr_err("failed to allocate efivar entry for '%s' EFI variable\n", name); |
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return -ENOMEM; |
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} |
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efibc_str_to_str16(name, entry->var.VariableName); |
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efibc_str_to_str16(value, (efi_char16_t *)entry->var.Data); |
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memcpy(&entry->var.VendorGuid, &guid, sizeof(guid)); |
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ret = efivar_entry_set_safe(entry->var.VariableName, |
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entry->var.VendorGuid, |
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EFI_VARIABLE_NON_VOLATILE |
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| EFI_VARIABLE_BOOTSERVICE_ACCESS |
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| EFI_VARIABLE_RUNTIME_ACCESS, |
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false, size, entry->var.Data); |
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if (ret) |
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pr_err("failed to set %s EFI variable: 0x%x\n", |
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name, ret); |
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kfree(entry); |
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return ret; |
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} |
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static int efibc_reboot_notifier_call(struct notifier_block *notifier, |
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unsigned long event, void *data) |
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{ |
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const char *reason = "shutdown"; |
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int ret; |
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if (event == SYS_RESTART) |
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reason = "reboot"; |
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ret = efibc_set_variable("LoaderEntryRebootReason", reason); |
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if (ret || !data) |
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return NOTIFY_DONE; |
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efibc_set_variable("LoaderEntryOneShot", (char *)data); |
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return NOTIFY_DONE; |
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} |
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static struct notifier_block efibc_reboot_notifier = { |
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.notifier_call = efibc_reboot_notifier_call, |
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}; |
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static int __init efibc_init(void) |
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{ |
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int ret; |
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if (!efivars_kobject() || !efivar_supports_writes()) |
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return -ENODEV; |
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ret = register_reboot_notifier(&efibc_reboot_notifier); |
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if (ret) |
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pr_err("unable to register reboot notifier\n"); |
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return ret; |
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} |
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module_init(efibc_init); |
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static void __exit efibc_exit(void) |
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{ |
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unregister_reboot_notifier(&efibc_reboot_notifier); |
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} |
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module_exit(efibc_exit); |
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MODULE_AUTHOR("Jeremy Compostella <[email protected]>"); |
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MODULE_AUTHOR("Matt Gumbel <[email protected]"); |
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MODULE_DESCRIPTION("EFI Bootloader Control"); |
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MODULE_LICENSE("GPL v2");
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