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path: root/drivers/firmware/efi/efi.c
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Diffstat (limited to 'drivers/firmware/efi/efi.c')
-rw-r--r--drivers/firmware/efi/efi.c134
1 files changed, 134 insertions, 0 deletions
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
new file mode 100644
index 000000000000..5145fa344ad5
--- /dev/null
+++ b/drivers/firmware/efi/efi.c
@@ -0,0 +1,134 @@
+/*
+ * efi.c - EFI subsystem
+ *
+ * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com>
+ * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com>
+ * Copyright (C) 2013 Tom Gundersen <teg@jklm.no>
+ *
+ * This code registers /sys/firmware/efi{,/efivars} when EFI is supported,
+ * allowing the efivarfs to be mounted or the efivars module to be loaded.
+ * The existance of /sys/firmware/efi may also be used by userspace to
+ * determine that the system supports EFI.
+ *
+ * This file is released under the GPLv2.
+ */
+
+#include <linux/kobject.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/efi.h>
+
+static struct kobject *efi_kobj;
+static struct kobject *efivars_kobj;
+
+/*
+ * Let's not leave out systab information that snuck into
+ * the efivars driver
+ */
+static ssize_t systab_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ char *str = buf;
+
+ if (!kobj || !buf)
+ return -EINVAL;
+
+ if (efi.mps != EFI_INVALID_TABLE_ADDR)
+ str += sprintf(str, "MPS=0x%lx\n", efi.mps);
+ if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
+ str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
+ if (efi.acpi != EFI_INVALID_TABLE_ADDR)
+ str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
+ if (efi.smbios != EFI_INVALID_TABLE_ADDR)
+ str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
+ if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
+ str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
+ if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
+ str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
+ if (efi.uga != EFI_INVALID_TABLE_ADDR)
+ str += sprintf(str, "UGA=0x%lx\n", efi.uga);
+
+ return str - buf;
+}
+
+static struct kobj_attribute efi_attr_systab =
+ __ATTR(systab, 0400, systab_show, NULL);
+
+static struct attribute *efi_subsys_attrs[] = {
+ &efi_attr_systab.attr,
+ NULL, /* maybe more in the future? */
+};
+
+static struct attribute_group efi_subsys_attr_group = {
+ .attrs = efi_subsys_attrs,
+};
+
+static struct efivars generic_efivars;
+static struct efivar_operations generic_ops;
+
+static int generic_ops_register(void)
+{
+ generic_ops.get_variable = efi.get_variable;
+ generic_ops.set_variable = efi.set_variable;
+ generic_ops.get_next_variable = efi.get_next_variable;
+ generic_ops.query_variable_store = efi_query_variable_store;
+
+ return efivars_register(&generic_efivars, &generic_ops, efi_kobj);
+}
+
+static void generic_ops_unregister(void)
+{
+ efivars_unregister(&generic_efivars);
+}
+
+/*
+ * We register the efi subsystem with the firmware subsystem and the
+ * efivars subsystem with the efi subsystem, if the system was booted with
+ * EFI.
+ */
+static int __init efisubsys_init(void)
+{
+ int error;
+
+ if (!efi_enabled(EFI_BOOT))
+ return 0;
+
+ /* We register the efi directory at /sys/firmware/efi */
+ efi_kobj = kobject_create_and_add("efi", firmware_kobj);
+ if (!efi_kobj) {
+ pr_err("efi: Firmware registration failed.\n");
+ return -ENOMEM;
+ }
+
+ error = generic_ops_register();
+ if (error)
+ goto err_put;
+
+ error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
+ if (error) {
+ pr_err("efi: Sysfs attribute export failed with error %d.\n",
+ error);
+ goto err_unregister;
+ }
+
+ /* and the standard mountpoint for efivarfs */
+ efivars_kobj = kobject_create_and_add("efivars", efi_kobj);
+ if (!efivars_kobj) {
+ pr_err("efivars: Subsystem registration failed.\n");
+ error = -ENOMEM;
+ goto err_remove_group;
+ }
+
+ return 0;
+
+err_remove_group:
+ sysfs_remove_group(efi_kobj, &efi_subsys_attr_group);
+err_unregister:
+ generic_ops_unregister();
+err_put:
+ kobject_put(efi_kobj);
+ return error;
+}
+
+subsys_initcall(efisubsys_init);