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Diffstat (limited to 'drivers/firmware/efi/efibc.c')
-rw-r--r--drivers/firmware/efi/efibc.c92
1 files changed, 92 insertions, 0 deletions
diff --git a/drivers/firmware/efi/efibc.c b/drivers/firmware/efi/efibc.c
new file mode 100644
index 000000000..4f9fb086e
--- /dev/null
+++ b/drivers/firmware/efi/efibc.c
@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * efibc: control EFI bootloaders which obey LoaderEntryOneShot var
+ * Copyright (c) 2013-2016, Intel Corporation.
+ */
+
+#define pr_fmt(fmt) "efibc: " fmt
+
+#include <linux/efi.h>
+#include <linux/module.h>
+#include <linux/reboot.h>
+#include <linux/slab.h>
+#include <linux/ucs2_string.h>
+
+#define MAX_DATA_LEN 512
+
+static int efibc_set_variable(efi_char16_t *name, efi_char16_t *value,
+ unsigned long len)
+{
+ efi_status_t status;
+
+ status = efi.set_variable(name, &LINUX_EFI_LOADER_ENTRY_GUID,
+ EFI_VARIABLE_NON_VOLATILE
+ | EFI_VARIABLE_BOOTSERVICE_ACCESS
+ | EFI_VARIABLE_RUNTIME_ACCESS,
+ len * sizeof(efi_char16_t), value);
+
+ if (status != EFI_SUCCESS) {
+ pr_err("failed to set EFI variable: 0x%lx\n", status);
+ return -EIO;
+ }
+ return 0;
+}
+
+static int efibc_reboot_notifier_call(struct notifier_block *notifier,
+ unsigned long event, void *data)
+{
+ efi_char16_t *reason = event == SYS_RESTART ? L"reboot"
+ : L"shutdown";
+ const u8 *str = data;
+ efi_char16_t *wdata;
+ unsigned long l;
+ int ret;
+
+ ret = efibc_set_variable(L"LoaderEntryRebootReason", reason,
+ ucs2_strlen(reason));
+ if (ret || !data)
+ return NOTIFY_DONE;
+
+ wdata = kmalloc(MAX_DATA_LEN * sizeof(efi_char16_t), GFP_KERNEL);
+ if (!wdata)
+ return NOTIFY_DONE;
+
+ for (l = 0; l < MAX_DATA_LEN - 1 && str[l] != '\0'; l++)
+ wdata[l] = str[l];
+ wdata[l] = L'\0';
+
+ efibc_set_variable(L"LoaderEntryOneShot", wdata, l);
+
+ kfree(wdata);
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block efibc_reboot_notifier = {
+ .notifier_call = efibc_reboot_notifier_call,
+};
+
+static int __init efibc_init(void)
+{
+ int ret;
+
+ if (!efi_rt_services_supported(EFI_RT_SUPPORTED_SET_VARIABLE))
+ return -ENODEV;
+
+ ret = register_reboot_notifier(&efibc_reboot_notifier);
+ if (ret)
+ pr_err("unable to register reboot notifier\n");
+
+ return ret;
+}
+module_init(efibc_init);
+
+static void __exit efibc_exit(void)
+{
+ unregister_reboot_notifier(&efibc_reboot_notifier);
+}
+module_exit(efibc_exit);
+
+MODULE_AUTHOR("Jeremy Compostella <jeremy.compostella@intel.com>");
+MODULE_AUTHOR("Matt Gumbel <matthew.k.gumbel@intel.com");
+MODULE_DESCRIPTION("EFI Bootloader Control");
+MODULE_LICENSE("GPL v2");