drivers/firmware/efi/Kconfig

   1 # SPDX-License-Identifier: GPL-2.0-only
   2 menu "EFI (Extensible Firmware Interface) Support"
   3         depends on EFI
   4
   5 config EFI_VARS
   6         tristate "EFI Variable Support via sysfs"
   7         depends on EFI
   8         default n
   9         help
  10           If you say Y here, you are able to get EFI (Extensible Firmware
  11           Interface) variable information via sysfs.  You may read,
  12           write, create, and destroy EFI variables through this interface.
  13
  14           Note that using this driver in concert with efibootmgr requires
  15           at least test release version 0.5.0-test3 or later, which is
  16           available from:
  17           <http://linux.dell.com/efibootmgr/testing/efibootmgr-0.5.0-test3.tar.gz>
  18
  19           Subsequent efibootmgr releases may be found at:
  20           <http://github.com/vathpela/efibootmgr>
  21
  22 config EFI_ESRT
  23         bool
  24         depends on EFI && !IA64
  25         default y
  26
  27 config EFI_VARS_PSTORE
  28         tristate "Register efivars backend for pstore"
  29         depends on EFI_VARS && PSTORE
  30         default y
  31         help
  32           Say Y here to enable use efivars as a backend to pstore. This
  33           will allow writing console messages, crash dumps, or anything
  34           else supported by pstore to EFI variables.
  35
  36 config EFI_VARS_PSTORE_DEFAULT_DISABLE
  37         bool "Disable using efivars as a pstore backend by default"
  38         depends on EFI_VARS_PSTORE
  39         default n
  40         help
  41           Saying Y here will disable the use of efivars as a storage
  42           backend for pstore by default. This setting can be overridden
  43           using the efivars module's pstore_disable parameter.
  44
  45 config EFI_RUNTIME_MAP
  46         bool "Export efi runtime maps to sysfs"
  47         depends on X86 && EFI && KEXEC_CORE
  48         default y
  49         help
  50           Export efi runtime memory maps to /sys/firmware/efi/runtime-map.
  51           That memory map is used for example by kexec to set up efi virtual
  52           mapping the 2nd kernel, but can also be used for debugging purposes.
  53
  54           See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
  55
  56 config EFI_FAKE_MEMMAP
  57         bool "Enable EFI fake memory map"
  58         depends on EFI && X86
  59         default n
  60         help
  61           Saying Y here will enable "efi_fake_mem" boot option.
  62           By specifying this parameter, you can add arbitrary attribute
  63           to specific memory range by updating original (firmware provided)
  64           EFI memmap.
  65           This is useful for debugging of EFI memmap related feature.
  66           e.g. Address Range Mirroring feature.
  67
  68 config EFI_MAX_FAKE_MEM
  69         int "maximum allowable number of ranges in efi_fake_mem boot option"
  70         depends on EFI_FAKE_MEMMAP
  71         range 1 128
  72         default 8
  73         help
  74           Maximum allowable number of ranges in efi_fake_mem boot option.
  75           Ranges can be set up to this value using comma-separated list.
  76           The default value is 8.
  77
  78 config EFI_PARAMS_FROM_FDT
  79         bool
  80         help
  81           Select this config option from the architecture Kconfig if
  82           the EFI runtime support gets system table address, memory
  83           map address, and other parameters from the device tree.
  84
  85 config EFI_RUNTIME_WRAPPERS
  86         bool
  87
  88 config EFI_ARMSTUB
  89         bool
  90
  91 config EFI_ARMSTUB_DTB_LOADER
  92         bool "Enable the DTB loader"
  93         depends on EFI_ARMSTUB
  94         default y
  95         help
  96           Select this config option to add support for the dtb= command
  97           line parameter, allowing a device tree blob to be loaded into
  98           memory from the EFI System Partition by the stub.
  99
 100           If the device tree is provided by the platform or by
 101           the bootloader this option may not be needed.
 102           But, for various development reasons and to maintain existing
 103           functionality for bootloaders that do not have such support
 104           this option is necessary.
 105
 106 config EFI_BOOTLOADER_CONTROL
 107         tristate "EFI Bootloader Control"
 108         depends on EFI_VARS
 109         default n
 110         ---help---
 111           This module installs a reboot hook, such that if reboot() is
 112           invoked with a string argument NNN, "NNN" is copied to the
 113           "LoaderEntryOneShot" EFI variable, to be read by the
 114           bootloader. If the string matches one of the boot labels
 115           defined in its configuration, the bootloader will boot once
 116           to that label. The "LoaderEntryRebootReason" EFI variable is
 117           set with the reboot reason: "reboot" or "shutdown". The
 118           bootloader reads this reboot reason and takes particular
 119           action according to its policy.
 120
 121 config EFI_CAPSULE_LOADER
 122         tristate "EFI capsule loader"
 123         depends on EFI
 124         help
 125           This option exposes a loader interface "/dev/efi_capsule_loader" for
 126           users to load EFI capsules. This driver requires working runtime
 127           capsule support in the firmware, which many OEMs do not provide.
 128
 129           Most users should say N.
 130
 131 config EFI_CAPSULE_QUIRK_QUARK_CSH
 132         bool "Add support for Quark capsules with non-standard headers"
 133         depends on X86 && !64BIT
 134         select EFI_CAPSULE_LOADER
 135         default y
 136         help
 137           Add support for processing Quark X1000 EFI capsules, whose header
 138           layout deviates from the layout mandated by the UEFI specification.
 139
 140 config EFI_TEST
 141         tristate "EFI Runtime Service Tests Support"
 142         depends on EFI
 143         default n
 144         help
 145           This driver uses the efi.<service> function pointers directly instead
 146           of going through the efivar API, because it is not trying to test the
 147           kernel subsystem, just for testing the UEFI runtime service
 148           interfaces which are provided by the firmware. This driver is used
 149           by the Firmware Test Suite (FWTS) for testing the UEFI runtime
 150           interfaces readiness of the firmware.
 151           Details for FWTS are available from:
 152           <https://wiki.ubuntu.com/FirmwareTestSuite>
 153
 154           Say Y here to enable the runtime services support via /dev/efi_test.
 155           If unsure, say N.
 156
 157 config APPLE_PROPERTIES
 158         bool "Apple Device Properties"
 159         depends on EFI_STUB && X86
 160         select EFI_DEV_PATH_PARSER
 161         select UCS2_STRING
 162         help
 163           Retrieve properties from EFI on Apple Macs and assign them to
 164           devices, allowing for improved support of Apple hardware.
 165           Properties that would otherwise be missing include the
 166           Thunderbolt Device ROM and GPU configuration data.
 167
 168           If unsure, say Y if you have a Mac.  Otherwise N.
 169
 170 config RESET_ATTACK_MITIGATION
 171         bool "Reset memory attack mitigation"
 172         depends on EFI_STUB
 173         help
 174           Request that the firmware clear the contents of RAM after a reboot
 175           using the TCG Platform Reset Attack Mitigation specification. This
 176           protects against an attacker forcibly rebooting the system while it
 177           still contains secrets in RAM, booting another OS and extracting the
 178           secrets. This should only be enabled when userland is configured to
 179           clear the MemoryOverwriteRequest flag on clean shutdown after secrets
 180           have been evicted, since otherwise it will trigger even on clean
 181           reboots.
 182
 183 endmenu
 184
 185 config UEFI_CPER
 186         bool
 187
 188 config UEFI_CPER_ARM
 189         bool
 190         depends on UEFI_CPER && ( ARM || ARM64 )
 191         default y
 192
 193 config UEFI_CPER_X86
 194         bool
 195         depends on UEFI_CPER && X86
 196         default y
 197
 198 config EFI_DEV_PATH_PARSER
 199         bool
 200         depends on ACPI
 201         default n
 202
 203 config EFI_EARLYCON
 204         def_bool y
 205         depends on SERIAL_EARLYCON && !ARM && !IA64
 206         select FONT_SUPPORT
 207         select ARCH_USE_MEMREMAP_PROT