Commit cfe3eceb authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'x86-efi-for-linus' of git://

Pull x86 EFI updates from Ingo Molnar:
 "EFI changes:

   - 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)"

* 'x86-efi-for-linus' of git://
  efi: Work around ia64 build problem with ESRT driver
  efi: Add 'systab' information to Documentation/ABI
  efi: dmi: List SMBIOS3 table before SMBIOS table
  efi/esrt: Fix some compiler warnings
  x86, doc: Remove cmdline_size from list of fields to be filled in for EFI handover
  efi: Add esrt support
  efi: efivar_create_sysfs_entry() should return negative error codes
parents 5ef6ca4f d4f77435
......@@ -18,3 +18,13 @@ Contact: Dave Young <>
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
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
What: /sys/firmware/efi/esrt/
Date: February 2015
Contact: Peter Jones <>
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 -
What: /sys/firmware/efi/esrt/fw_resource_count
Date: February 2015
Contact: Peter Jones <>
Description: The number of entries in the ESRT
What: /sys/firmware/efi/esrt/fw_resource_count_max
Date: February 2015
Contact: Peter Jones <>
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 <>
Description: The version of the ESRT structure provided by the firmware.
What: /sys/firmware/efi/esrt/entries/entry$N/
Date: February 2015
Contact: Peter Jones <>
Description: Each ESRT entry is identified by a GUID, and each gets a
subdirectory under entries/ .
example: /sys/firmware/efi/esrt/entries/entry0/
What: /sys/firmware/efi/esrt/entries/entry$N/fw_type
Date: February 2015
Contact: Peter Jones <>
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$N/fw_class
Date: February 2015
Contact: Peter Jones <>
Description: This is the entry's guid, and will match the directory name.
What: /sys/firmware/efi/esrt/entries/entry$N/fw_version
Date: February 2015
Contact: Peter Jones <>
Description: The version of the firmware currently installed. This is a
32-bit unsigned integer.
What: /sys/firmware/efi/esrt/entries/entry$N/lowest_supported_fw_version
Date: February 2015
Contact: Peter Jones <>
Description: The lowest version of the firmware that can be installed.
What: /sys/firmware/efi/esrt/entries/entry$N/capsule_flags
Date: February 2015
Contact: Peter Jones <>
Description: Flags that must be passed to UpdateCapsule()
What: /sys/firmware/efi/esrt/entries/entry$N/last_attempt_version
Date: February 2015
Contact: Peter Jones <>
Description: The last firmware version for which an update was attempted.
What: /sys/firmware/efi/esrt/entries/entry$N/last_attempt_status
Date: February 2015
Contact: Peter Jones <>
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
......@@ -1124,7 +1124,6 @@ The boot loader *must* fill out the following fields in bp,
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)
......@@ -501,6 +501,8 @@ void __init efi_init(void)
if (efi_enabled(EFI_DBG))
void __init efi_late_init(void)
......@@ -18,6 +18,11 @@ config EFI_VARS
Subsequent efibootmgr releases may be found at:
config EFI_ESRT
depends on EFI && !IA64
default y
tristate "Register efivars backend for pstore"
depends on EFI_VARS && PSTORE
......@@ -3,6 +3,7 @@
obj-$(CONFIG_EFI) += efi.o vars.o reboot.o
obj-$(CONFIG_EFI_VARS) += efivars.o
obj-$(CONFIG_EFI_ESRT) += esrt.o
obj-$(CONFIG_EFI_VARS_PSTORE) += efi-pstore.o
obj-$(CONFIG_UEFI_CPER) += cper.o
obj-$(CONFIG_EFI_RUNTIME_MAP) += runtime-map.o
......@@ -39,6 +39,7 @@ struct efi __read_mostly efi = {
.config_table = EFI_INVALID_TABLE_ADDR,
......@@ -64,7 +65,7 @@ static int __init parse_efi_cmdline(char *str)
early_param("efi", parse_efi_cmdline);
static struct kobject *efi_kobj;
struct kobject *efi_kobj;
static struct kobject *efivars_kobj;
......@@ -85,10 +86,15 @@ static ssize_t systab_show(struct kobject *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)
......@@ -232,6 +238,84 @@ err_put:
* 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) &&
early_memunmap(md, sizeof (*md));
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
......@@ -274,6 +358,7 @@ static __initdata efi_config_table_type_t common_tables[] = {
{SMBIOS_TABLE_GUID, "SMBIOS", &efi.smbios},
{SMBIOS3_TABLE_GUID, "SMBIOS 3.0", &efi.smbios3},
{UGA_IO_PROTOCOL_GUID, "UGA", &efi.uga},
......@@ -535,7 +535,7 @@ static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
* 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)
......@@ -544,6 +544,7 @@ 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);
......@@ -558,7 +559,7 @@ efivar_create_sysfs_entry(struct efivar_entry *new_var)
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 */
......@@ -574,11 +575,11 @@ efivar_create_sysfs_entry(struct efivar_entry *new_var)
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);
if (i)
return 1;
if (ret)
return ret;
kobject_uevent(&new_var->kobj, KOBJ_ADD);
efivar_entry_add(new_var, &efivar_sysfs_list);
* 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[] = {
static void esre_release(struct kobject *kobj)
struct esre_entry *entry = to_entry(kobj);
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) {
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[] = {
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())
rc = efi_mem_desc_lookup(efi.esrt, &md);
if (rc < 0) {
pr_err("ESRT header is not in the memory map.\n");
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);
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);
va = early_memremap(efi.esrt, size);
if (!va) {
pr_err("early_memremap(%p, %zu) failed.\n", (void *)efi.esrt,
memcpy(&tmpesrt, va, sizeof(tmpesrt));
if (tmpesrt.fw_resource_version == 1) {
entry_size = sizeof (*v1_entries);
} else {
pr_err("Unsupported ESRT version %lld.\n",
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",
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.