Merge tag 'efi-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi into x86/efi

Pull EFI changes from Matt Fleming:

- Use idiomatic negative error values in efivar_create_sysfs_entry()
instead of returning '1' to indicate error. (Dan Carpenter)

- Implement new support to expose the EFI System Resource Tables in sysfs,
which provides information for performing firmware updates. (Peter Jones)

- Documentation cleanup in the EFI handover protocol section which
falsely claimed that 'cmdline_size' needed to be filled out by the
boot loader. (Alex Smith)

- Align the order of SMBIOS tables in /sys/firmware/efi/systab to match
the way that we do things for ACPI and add documentation to
Documentation/ABI. (Jean Delvare)

Signed-off-by: Ingo Molnar <[e-mail]>

Documentation/ABI/testing/sysfs-firmware-efi

···
 Description:	It shows the physical address of config table entry in the EFI
 		system table.
 Users:		Kexec
+
+What:		/sys/firmware/efi/systab
+Date:		April 2005
+Contact:	[e-mail]
+Description:	Displays the physical addresses of all EFI Configuration
+		Tables found via the EFI System Table. The order in
+		which the tables are printed forms an ABI and newer
+		versions are always printed first, i.e. ACPI20 comes
+		before ACPI.
+Users:		dmidecode

Documentation/ABI/testing/sysfs-firmware-efi-esrt

···
+What:		/sys/firmware/efi/esrt/
+Date:		February 2015
+Contact:	Peter Jones <[e-mail]>
+Description:	Provides userland access to read the EFI System Resource Table
+		(ESRT), a catalog of firmware for which can be updated with
+		the UEFI UpdateCapsule mechanism described in section 7.5 of
+		the UEFI Standard.
+Users:		fwupdate - https://github.com/rhinstaller/fwupdate
+
+What:		/sys/firmware/efi/esrt/fw_resource_count
+Date:		February 2015
+Contact:	Peter Jones <[e-mail]>
+Description:	The number of entries in the ESRT
+
+What:		/sys/firmware/efi/esrt/fw_resource_count_max
+Date:		February 2015
+Contact:	Peter Jones <[e-mail]>
+Description:	The maximum number of entries that /could/ be registered
+		in the allocation the table is currently in.  This is
+		really only useful to the system firmware itself.
+
+What:		/sys/firmware/efi/esrt/fw_resource_version
+Date:		February 2015
+Contact:	Peter Jones <[e-mail]>
+Description:	The version of the ESRT structure provided by the firmware.
+
+What:		/sys/firmware/efi/esrt/entries/entry$N/
+Date:		February 2015
+Contact:	Peter Jones <[e-mail]>
+Description:	Each ESRT entry is identified by a GUID, and each gets a
+		subdirectory under entries/ .
+		example: /sys/firmware/efi/esrt/entries/entry0/
+
+What:		/sys/firmware/efi/esrt/entries/entry$N/fw_type
+Date:		February 2015
+Contact:	Peter Jones <[e-mail]>
+Description:	What kind of firmware entry this is:
+		0 - Unknown
+		1 - System Firmware
+		2 - Device Firmware
+		3 - UEFI Driver
+
+What:		/sys/firmware/efi/esrt/entries/entry$N/fw_class
+Date:		February 2015
+Contact:	Peter Jones <[e-mail]>
+Description:	This is the entry's guid, and will match the directory name.
+
+What:		/sys/firmware/efi/esrt/entries/entry$N/fw_version
+Date:		February 2015
+Contact:	Peter Jones <[e-mail]>
+Description:	The version of the firmware currently installed.  This is a
+		32-bit unsigned integer.
+
+What:		/sys/firmware/efi/esrt/entries/entry$N/lowest_supported_fw_version
+Date:		February 2015
+Contact:	Peter Jones <[e-mail]>
+Description:	The lowest version of the firmware that can be installed.
+
+What:		/sys/firmware/efi/esrt/entries/entry$N/capsule_flags
+Date:		February 2015
+Contact:	Peter Jones <[e-mail]>
+Description:	Flags that must be passed to UpdateCapsule()
+
+What:		/sys/firmware/efi/esrt/entries/entry$N/last_attempt_version
+Date:		February 2015
+Contact:	Peter Jones <[e-mail]>
+Description:	The last firmware version for which an update was attempted.
+
+What:		/sys/firmware/efi/esrt/entries/entry$N/last_attempt_status
+Date:		February 2015
+Contact:	Peter Jones <[e-mail]>
+Description:	The result of the last firmware update attempt for the
+		firmware resource entry.
+		0 - Success
+		1 - Insufficient resources
+		2 - Incorrect version
+		3 - Invalid format
+		4 - Authentication error
+		5 - AC power event
+		6 - Battery power event
+

Documentation/x86/boot.txt

···
 
     o hdr.code32_start
     o hdr.cmd_line_ptr
-    o hdr.cmdline_size
     o hdr.ramdisk_image (if applicable)
     o hdr.ramdisk_size  (if applicable)
 

arch/x86/platform/efi/efi.c

···
 
 	if (efi_enabled(EFI_DBG))
 		print_efi_memmap();
+
+	efi_esrt_init();
 }
 
 void __init efi_late_init(void)

drivers/firmware/efi/Makefile

···
 #
 # Makefile for linux kernel
 #
-obj-$(CONFIG_EFI)			+= efi.o vars.o reboot.o
+obj-$(CONFIG_EFI)			+= efi.o esrt.o vars.o reboot.o
 obj-$(CONFIG_EFI_VARS)			+= efivars.o
 obj-$(CONFIG_EFI_VARS_PSTORE)		+= efi-pstore.o
 obj-$(CONFIG_UEFI_CPER)			+= cper.o

drivers/firmware/efi/efi.c

···
 	.fw_vendor  = EFI_INVALID_TABLE_ADDR,
 	.runtime    = EFI_INVALID_TABLE_ADDR,
 	.config_table  = EFI_INVALID_TABLE_ADDR,
+	.esrt       = EFI_INVALID_TABLE_ADDR,
 };
 EXPORT_SYMBOL(efi);
 
···
 }
 early_param("efi", parse_efi_cmdline);
 
-static struct kobject *efi_kobj;
+struct kobject *efi_kobj;
 static struct kobject *efivars_kobj;
 
 /*
···
 		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 both SMBIOS and SMBIOS3 entry points are implemented, the
+	 * SMBIOS3 entry point shall be preferred, so we list it first to
+	 * let applications stop parsing after the first match.
+	 */
 	if (efi.smbios3 != EFI_INVALID_TABLE_ADDR)
 		str += sprintf(str, "SMBIOS3=0x%lx\n", efi.smbios3);
+	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)
···
 
 subsys_initcall(efisubsys_init);
 
+/*
+ * Find the efi memory descriptor for a given physical address.  Given a
+ * physicall address, determine if it exists within an EFI Memory Map entry,
+ * and if so, populate the supplied memory descriptor with the appropriate
+ * data.
+ */
+int __init efi_mem_desc_lookup(u64 phys_addr, efi_memory_desc_t *out_md)
+{
+	struct efi_memory_map *map = efi.memmap;
+	void *p, *e;
+
+	if (!efi_enabled(EFI_MEMMAP)) {
+		pr_err_once("EFI_MEMMAP is not enabled.\n");
+		return -EINVAL;
+	}
+
+	if (!map) {
+		pr_err_once("efi.memmap is not set.\n");
+		return -EINVAL;
+	}
+	if (!out_md) {
+		pr_err_once("out_md is null.\n");
+		return -EINVAL;
+        }
+	if (WARN_ON_ONCE(!map->phys_map))
+		return -EINVAL;
+	if (WARN_ON_ONCE(map->nr_map == 0) || WARN_ON_ONCE(map->desc_size == 0))
+		return -EINVAL;
+
+	e = map->phys_map + map->nr_map * map->desc_size;
+	for (p = map->phys_map; p < e; p += map->desc_size) {
+		efi_memory_desc_t *md;
+		u64 size;
+		u64 end;
+
+		/*
+		 * If a driver calls this after efi_free_boot_services,
+		 * ->map will be NULL, and the target may also not be mapped.
+		 * So just always get our own virtual map on the CPU.
+		 *
+		 */
+		md = early_memremap((phys_addr_t)p, sizeof (*md));
+		if (!md) {
+			pr_err_once("early_memremap(%p, %zu) failed.\n",
+				    p, sizeof (*md));
+			return -ENOMEM;
+		}
+
+		if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
+		    md->type != EFI_BOOT_SERVICES_DATA &&
+		    md->type != EFI_RUNTIME_SERVICES_DATA) {
+			early_memunmap(md, sizeof (*md));
+			continue;
+		}
+
+		size = md->num_pages << EFI_PAGE_SHIFT;
+		end = md->phys_addr + size;
+		if (phys_addr >= md->phys_addr && phys_addr < end) {
+			memcpy(out_md, md, sizeof(*out_md));
+			early_memunmap(md, sizeof (*md));
+			return 0;
+		}
+
+		early_memunmap(md, sizeof (*md));
+	}
+	pr_err_once("requested map not found.\n");
+	return -ENOENT;
+}
+
+/*
+ * Calculate the highest address of an efi memory descriptor.
+ */
+u64 __init efi_mem_desc_end(efi_memory_desc_t *md)
+{
+	u64 size = md->num_pages << EFI_PAGE_SHIFT;
+	u64 end = md->phys_addr + size;
+	return end;
+}
 
 /*
  * We can't ioremap data in EFI boot services RAM, because we've already mapped
···
 	{SMBIOS_TABLE_GUID, "SMBIOS", &efi.smbios},
 	{SMBIOS3_TABLE_GUID, "SMBIOS 3.0", &efi.smbios3},
 	{UGA_IO_PROTOCOL_GUID, "UGA", &efi.uga},
+	{EFI_SYSTEM_RESOURCE_TABLE_GUID, "ESRT", &efi.esrt},
 	{NULL_GUID, NULL, NULL},
 };
 

drivers/firmware/efi/efivars.c

···
  * efivar_create_sysfs_entry - create a new entry in sysfs
  * @new_var: efivar entry to create
  *
- * Returns 1 on failure, 0 on success
+ * Returns 0 on success, negative error code on failure
  */
 static int
 efivar_create_sysfs_entry(struct efivar_entry *new_var)
···
 	char *short_name;
 	unsigned long variable_name_size;
 	efi_char16_t *variable_name;
+	int ret;
 
 	variable_name = new_var->var.VariableName;
 	variable_name_size = ucs2_strlen(variable_name) * sizeof(efi_char16_t);
···
 	short_name = kzalloc(short_name_size, GFP_KERNEL);
 
 	if (!short_name)
-		return 1;
+		return -ENOMEM;
 
 	/* Convert Unicode to normal chars (assume top bits are 0),
 	   ala UTF-8 */
···
 
 	new_var->kobj.kset = efivars_kset;
 
-	i = kobject_init_and_add(&new_var->kobj, &efivar_ktype,
+	ret = kobject_init_and_add(&new_var->kobj, &efivar_ktype,
 				   NULL, "%s", short_name);
 	kfree(short_name);
-	if (i)
-		return 1;
+	if (ret)
+		return ret;
 
 	kobject_uevent(&new_var->kobj, KOBJ_ADD);
 	efivar_entry_add(new_var, &efivar_sysfs_list);

drivers/firmware/efi/esrt.c

···
+/*
+ * esrt.c
+ *
+ * This module exports EFI System Resource Table (ESRT) entries into userspace
+ * through the sysfs file system. The ESRT provides a read-only catalog of
+ * system components for which the system accepts firmware upgrades via UEFI's
+ * "Capsule Update" feature. This module allows userland utilities to evaluate
+ * what firmware updates can be applied to this system, and potentially arrange
+ * for those updates to occur.
+ *
+ * Data is currently found below /sys/firmware/efi/esrt/...
+ */
+#define pr_fmt(fmt) "esrt: " fmt
+
+#include <linux/capability.h>
+#include <linux/device.h>
+#include <linux/efi.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/kobject.h>
+#include <linux/list.h>
+#include <linux/memblock.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include <asm/io.h>
+#include <asm/early_ioremap.h>
+
+struct efi_system_resource_entry_v1 {
+	efi_guid_t	fw_class;
+	u32		fw_type;
+	u32		fw_version;
+	u32		lowest_supported_fw_version;
+	u32		capsule_flags;
+	u32		last_attempt_version;
+	u32		last_attempt_status;
+};
+
+/*
+ * _count and _version are what they seem like.  _max is actually just
+ * accounting info for the firmware when creating the table; it should never
+ * have been exposed to us.  To wit, the spec says:
+ * The maximum number of resource array entries that can be within the
+ * table without reallocating the table, must not be zero.
+ * Since there's no guidance about what that means in terms of memory layout,
+ * it means nothing to us.
+ */
+struct efi_system_resource_table {
+	u32	fw_resource_count;
+	u32	fw_resource_count_max;
+	u64	fw_resource_version;
+	u8	entries[];
+};
+
+static phys_addr_t esrt_data;
+static size_t esrt_data_size;
+
+static struct efi_system_resource_table *esrt;
+
+struct esre_entry {
+	union {
+		struct efi_system_resource_entry_v1 *esre1;
+	} esre;
+
+	struct kobject kobj;
+	struct list_head list;
+};
+
+/* global list of esre_entry. */
+static LIST_HEAD(entry_list);
+
+/* entry attribute */
+struct esre_attribute {
+	struct attribute attr;
+	ssize_t (*show)(struct esre_entry *entry, char *buf);
+	ssize_t (*store)(struct esre_entry *entry,
+			 const char *buf, size_t count);
+};
+
+static struct esre_entry *to_entry(struct kobject *kobj)
+{
+	return container_of(kobj, struct esre_entry, kobj);
+}
+
+static struct esre_attribute *to_attr(struct attribute *attr)
+{
+	return container_of(attr, struct esre_attribute, attr);
+}
+
+static ssize_t esre_attr_show(struct kobject *kobj,
+			      struct attribute *_attr, char *buf)
+{
+	struct esre_entry *entry = to_entry(kobj);
+	struct esre_attribute *attr = to_attr(_attr);
+
+	/* Don't tell normal users what firmware versions we've got... */
+	if (!capable(CAP_SYS_ADMIN))
+		return -EACCES;
+
+	return attr->show(entry, buf);
+}
+
+static const struct sysfs_ops esre_attr_ops = {
+	.show = esre_attr_show,
+};
+
+/* Generic ESRT Entry ("ESRE") support. */
+static ssize_t esre_fw_class_show(struct esre_entry *entry, char *buf)
+{
+	char *str = buf;
+
+	efi_guid_to_str(&entry->esre.esre1->fw_class, str);
+	str += strlen(str);
+	str += sprintf(str, "\n");
+
+	return str - buf;
+}
+
+static struct esre_attribute esre_fw_class = __ATTR(fw_class, 0400,
+	esre_fw_class_show, NULL);
+
+#define esre_attr_decl(name, size, fmt) \
+static ssize_t esre_##name##_show(struct esre_entry *entry, char *buf) \
+{ \
+	return sprintf(buf, fmt "\n", \
+		       le##size##_to_cpu(entry->esre.esre1->name)); \
+} \
+\
+static struct esre_attribute esre_##name = __ATTR(name, 0400, \
+	esre_##name##_show, NULL)
+
+esre_attr_decl(fw_type, 32, "%u");
+esre_attr_decl(fw_version, 32, "%u");
+esre_attr_decl(lowest_supported_fw_version, 32, "%u");
+esre_attr_decl(capsule_flags, 32, "0x%x");
+esre_attr_decl(last_attempt_version, 32, "%u");
+esre_attr_decl(last_attempt_status, 32, "%u");
+
+static struct attribute *esre1_attrs[] = {
+	&esre_fw_class.attr,
+	&esre_fw_type.attr,
+	&esre_fw_version.attr,
+	&esre_lowest_supported_fw_version.attr,
+	&esre_capsule_flags.attr,
+	&esre_last_attempt_version.attr,
+	&esre_last_attempt_status.attr,
+	NULL
+};
+static void esre_release(struct kobject *kobj)
+{
+	struct esre_entry *entry = to_entry(kobj);
+
+	list_del(&entry->list);
+	kfree(entry);
+}
+
+static struct kobj_type esre1_ktype = {
+	.release = esre_release,
+	.sysfs_ops = &esre_attr_ops,
+	.default_attrs = esre1_attrs,
+};
+
+
+static struct kobject *esrt_kobj;
+static struct kset *esrt_kset;
+
+static int esre_create_sysfs_entry(void *esre, int entry_num)
+{
+	struct esre_entry *entry;
+	char name[20];
+
+	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+	if (!entry)
+		return -ENOMEM;
+
+	sprintf(name, "entry%d", entry_num);
+
+	entry->kobj.kset = esrt_kset;
+
+	if (esrt->fw_resource_version == 1) {
+		int rc = 0;
+
+		entry->esre.esre1 = esre;
+		rc = kobject_init_and_add(&entry->kobj, &esre1_ktype, NULL,
+					  "%s", name);
+		if (rc) {
+			kfree(entry);
+			return rc;
+		}
+	}
+
+	list_add_tail(&entry->list, &entry_list);
+	return 0;
+}
+
+/* support for displaying ESRT fields at the top level */
+#define esrt_attr_decl(name, size, fmt) \
+static ssize_t esrt_##name##_show(struct kobject *kobj, \
+				  struct kobj_attribute *attr, char *buf)\
+{ \
+	return sprintf(buf, fmt "\n", le##size##_to_cpu(esrt->name)); \
+} \
+\
+static struct kobj_attribute esrt_##name = __ATTR(name, 0400, \
+	esrt_##name##_show, NULL)
+
+esrt_attr_decl(fw_resource_count, 32, "%u");
+esrt_attr_decl(fw_resource_count_max, 32, "%u");
+esrt_attr_decl(fw_resource_version, 64, "%llu");
+
+static struct attribute *esrt_attrs[] = {
+	&esrt_fw_resource_count.attr,
+	&esrt_fw_resource_count_max.attr,
+	&esrt_fw_resource_version.attr,
+	NULL,
+};
+
+static inline int esrt_table_exists(void)
+{
+	if (!efi_enabled(EFI_CONFIG_TABLES))
+		return 0;
+	if (efi.esrt == EFI_INVALID_TABLE_ADDR)
+		return 0;
+	return 1;
+}
+
+static umode_t esrt_attr_is_visible(struct kobject *kobj,
+				    struct attribute *attr, int n)
+{
+	if (!esrt_table_exists())
+		return 0;
+	return attr->mode;
+}
+
+static struct attribute_group esrt_attr_group = {
+	.attrs = esrt_attrs,
+	.is_visible = esrt_attr_is_visible,
+};
+
+/*
+ * remap the table, copy it to kmalloced pages, and unmap it.
+ */
+void __init efi_esrt_init(void)
+{
+	void *va;
+	struct efi_system_resource_table tmpesrt;
+	struct efi_system_resource_entry_v1 *v1_entries;
+	size_t size, max, entry_size, entries_size;
+	efi_memory_desc_t md;
+	int rc;
+	phys_addr_t end;
+
+	pr_debug("esrt-init: loading.\n");
+	if (!esrt_table_exists())
+		return;
+
+	rc = efi_mem_desc_lookup(efi.esrt, &md);
+	if (rc < 0) {
+		pr_err("ESRT header is not in the memory map.\n");
+		return;
+	}
+
+	max = efi_mem_desc_end(&md);
+	if (max < efi.esrt) {
+		pr_err("EFI memory descriptor is invalid. (esrt: %p max: %p)\n",
+		       (void *)efi.esrt, (void *)max);
+		return;
+	}
+
+	size = sizeof(*esrt);
+	max -= efi.esrt;
+
+	if (max < size) {
+		pr_err("ESRT header doen't fit on single memory map entry. (size: %zu max: %zu)\n",
+		       size, max);
+		return;
+	}
+
+	va = early_memremap(efi.esrt, size);
+	if (!va) {
+		pr_err("early_memremap(%p, %zu) failed.\n", (void *)efi.esrt,
+		       size);
+		return;
+	}
+
+	memcpy(&tmpesrt, va, sizeof(tmpesrt));
+
+	if (tmpesrt.fw_resource_version == 1) {
+		entry_size = sizeof (*v1_entries);
+	} else {
+		pr_err("Unsupported ESRT version %lld.\n",
+		       tmpesrt.fw_resource_version);
+		return;
+	}
+
+	if (tmpesrt.fw_resource_count > 0 && max - size < entry_size) {
+		pr_err("ESRT memory map entry can only hold the header. (max: %zu size: %zu)\n",
+		       max - size, entry_size);
+		goto err_memunmap;
+	}
+
+	/*
+	 * The format doesn't really give us any boundary to test here,
+	 * so I'm making up 128 as the max number of individually updatable
+	 * components we support.
+	 * 128 should be pretty excessive, but there's still some chance
+	 * somebody will do that someday and we'll need to raise this.
+	 */
+	if (tmpesrt.fw_resource_count > 128) {
+		pr_err("ESRT says fw_resource_count has very large value %d.\n",
+		       tmpesrt.fw_resource_count);
+		goto err_memunmap;
+	}
+
+	/*
+	 * We know it can't be larger than N * sizeof() here, and N is limited
+	 * by the previous test to a small number, so there's no overflow.
+	 */
+	entries_size = tmpesrt.fw_resource_count * entry_size;
+	if (max < size + entries_size) {
+		pr_err("ESRT does not fit on single memory map entry (size: %zu max: %zu)\n",
+		       size, max);
+		goto err_memunmap;
+	}
+
+	/* remap it with our (plausible) new pages */
+	early_memunmap(va, size);
+	size += entries_size;
+	va = early_memremap(efi.esrt, size);
+	if (!va) {
+		pr_err("early_memremap(%p, %zu) failed.\n", (void *)efi.esrt,
+		       size);
+		return;
+	}
+
+	esrt_data = (phys_addr_t)efi.esrt;
+	esrt_data_size = size;
+
+	end = esrt_data + size;
+	pr_info("Reserving ESRT space from %pa to %pa.\n", &esrt_data, &end);
+	memblock_reserve(esrt_data, esrt_data_size);
+
+	pr_debug("esrt-init: loaded.\n");
+err_memunmap:
+	early_memunmap(va, size);
+}
+
+static int __init register_entries(void)
+{
+	struct efi_system_resource_entry_v1 *v1_entries = (void *)esrt->entries;
+	int i, rc;
+
+	if (!esrt_table_exists())
+		return 0;
+
+	for (i = 0; i < le32_to_cpu(esrt->fw_resource_count); i++) {
+		void *esre = NULL;
+		if (esrt->fw_resource_version == 1) {
+			esre = &v1_entries[i];
+		} else {
+			pr_err("Unsupported ESRT version %lld.\n",
+			       esrt->fw_resource_version);
+			return -EINVAL;
+		}
+
+		rc = esre_create_sysfs_entry(esre, i);
+		if (rc < 0) {
+			pr_err("ESRT entry creation failed with error %d.\n",
+			       rc);
+			return rc;
+		}
+	}
+	return 0;
+}
+
+static void cleanup_entry_list(void)
+{
+	struct esre_entry *entry, *next;
+
+	list_for_each_entry_safe(entry, next, &entry_list, list) {
+		kobject_put(&entry->kobj);
+	}
+}
+
+static int __init esrt_sysfs_init(void)
+{
+	int error;
+	struct efi_system_resource_table __iomem *ioesrt;
+
+	pr_debug("esrt-sysfs: loading.\n");
+	if (!esrt_data || !esrt_data_size)
+		return -ENOSYS;
+
+	ioesrt = ioremap(esrt_data, esrt_data_size);
+	if (!ioesrt) {
+		pr_err("ioremap(%pa, %zu) failed.\n", &esrt_data,
+		       esrt_data_size);
+		return -ENOMEM;
+	}
+
+	esrt = kmalloc(esrt_data_size, GFP_KERNEL);
+	if (!esrt) {
+		pr_err("kmalloc failed. (wanted %zu bytes)\n", esrt_data_size);
+		iounmap(ioesrt);
+		return -ENOMEM;
+	}
+
+	memcpy_fromio(esrt, ioesrt, esrt_data_size);
+
+	esrt_kobj = kobject_create_and_add("esrt", efi_kobj);
+	if (!esrt_kobj) {
+		pr_err("Firmware table registration failed.\n");
+		error = -ENOMEM;
+		goto err;
+	}
+
+	error = sysfs_create_group(esrt_kobj, &esrt_attr_group);
+	if (error) {
+		pr_err("Sysfs attribute export failed with error %d.\n",
+		       error);
+		goto err_remove_esrt;
+	}
+
+	esrt_kset = kset_create_and_add("entries", NULL, esrt_kobj);
+	if (!esrt_kset) {
+		pr_err("kset creation failed.\n");
+		error = -ENOMEM;
+		goto err_remove_group;
+	}
+
+	error = register_entries();
+	if (error)
+		goto err_cleanup_list;
+
+	memblock_remove(esrt_data, esrt_data_size);
+
+	pr_debug("esrt-sysfs: loaded.\n");
+
+	return 0;
+err_cleanup_list:
+	cleanup_entry_list();
+	kset_unregister(esrt_kset);
+err_remove_group:
+	sysfs_remove_group(esrt_kobj, &esrt_attr_group);
+err_remove_esrt:
+	kobject_put(esrt_kobj);
+err:
+	kfree(esrt);
+	esrt = NULL;
+	return error;
+}
+
+static void __exit esrt_sysfs_exit(void)
+{
+	pr_debug("esrt-sysfs: unloading.\n");
+	cleanup_entry_list();
+	kset_unregister(esrt_kset);
+	sysfs_remove_group(esrt_kobj, &esrt_attr_group);
+	kfree(esrt);
+	esrt = NULL;
+	kobject_del(esrt_kobj);
+	kobject_put(esrt_kobj);
+}
+
+module_init(esrt_sysfs_init);
+module_exit(esrt_sysfs_exit);
+
+MODULE_AUTHOR("Peter Jones <[e-mail]>");
+MODULE_DESCRIPTION("EFI System Resource Table support");
+MODULE_LICENSE("GPL");

include/linux/efi.h

···
 #define EFI_FILE_INFO_ID \
     EFI_GUID(  0x9576e92, 0x6d3f, 0x11d2, 0x8e, 0x39, 0x00, 0xa0, 0xc9, 0x69, 0x72, 0x3b )
 
+#define EFI_SYSTEM_RESOURCE_TABLE_GUID \
+    EFI_GUID(  0xb122a263, 0x3661, 0x4f68, 0x99, 0x29, 0x78, 0xf8, 0xb0, 0xd6, 0x21, 0x80 )
+
 #define EFI_FILE_SYSTEM_GUID \
     EFI_GUID(  0x964e5b22, 0x6459, 0x11d2, 0x8e, 0x39, 0x00, 0xa0, 0xc9, 0x69, 0x72, 0x3b )
 
···
 	unsigned long fw_vendor;	/* fw_vendor */
 	unsigned long runtime;		/* runtime table */
 	unsigned long config_table;	/* config tables */
+	unsigned long esrt;		/* ESRT table */
 	efi_get_time_t *get_time;
 	efi_set_time_t *set_time;
 	efi_get_wakeup_time_t *get_wakeup_time;
···
 #endif
 extern void __iomem *efi_lookup_mapped_addr(u64 phys_addr);
 extern int efi_config_init(efi_config_table_type_t *arch_tables);
+extern void __init efi_esrt_init(void);
 extern int efi_config_parse_tables(void *config_tables, int count, int sz,
 				   efi_config_table_type_t *arch_tables);
 extern u64 efi_get_iobase (void);
···
 extern u64 efi_mem_attributes (unsigned long phys_addr);
 extern u64 efi_mem_attribute (unsigned long phys_addr, unsigned long size);
 extern int __init efi_uart_console_only (void);
+extern u64 efi_mem_desc_end(efi_memory_desc_t *md);
+extern int efi_mem_desc_lookup(u64 phys_addr, efi_memory_desc_t *out_md);
 extern void efi_initialize_iomem_resources(struct resource *code_resource,
 		struct resource *data_resource, struct resource *bss_resource);
 extern void efi_get_time(struct timespec *now);
 extern void efi_reserve_boot_services(void);
 extern int efi_get_fdt_params(struct efi_fdt_params *params, int verbose);
 extern struct efi_memory_map memmap;
+extern struct kobject *efi_kobj;
 
 extern int efi_reboot_quirk_mode;
 extern bool efi_poweroff_required(void);