93 lines
2.2 KiB
C
93 lines
2.2 KiB
C
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// 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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#include <linux/ucs2_string.h>
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#define MAX_DATA_LEN 512
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static int efibc_set_variable(efi_char16_t *name, efi_char16_t *value,
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unsigned long len)
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{
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efi_status_t status;
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status = efi.set_variable(name, &LINUX_EFI_LOADER_ENTRY_GUID,
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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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len * sizeof(efi_char16_t), value);
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if (status != EFI_SUCCESS) {
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pr_err("failed to set EFI variable: 0x%lx\n", status);
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return -EIO;
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}
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return 0;
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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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efi_char16_t *reason = event == SYS_RESTART ? L"reboot"
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: L"shutdown";
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const u8 *str = data;
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efi_char16_t *wdata;
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unsigned long l;
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int ret;
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ret = efibc_set_variable(L"LoaderEntryRebootReason", reason,
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ucs2_strlen(reason));
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if (ret || !data)
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return NOTIFY_DONE;
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wdata = kmalloc(MAX_DATA_LEN * sizeof(efi_char16_t), GFP_KERNEL);
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if (!wdata)
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return NOTIFY_DONE;
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for (l = 0; l < MAX_DATA_LEN - 1 && str[l] != '\0'; l++)
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wdata[l] = str[l];
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wdata[l] = L'\0';
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efibc_set_variable(L"LoaderEntryOneShot", wdata, l);
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kfree(wdata);
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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 (!efi_rt_services_supported(EFI_RT_SUPPORTED_SET_VARIABLE))
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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 <jeremy.compostella@intel.com>");
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MODULE_AUTHOR("Matt Gumbel <matthew.k.gumbel@intel.com");
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MODULE_DESCRIPTION("EFI Bootloader Control");
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MODULE_LICENSE("GPL v2");
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