arch/x86/Kconfig

menu "x86 architecture"
	depends on X86

config SYS_ARCH
	default "x86"

choice
	prompt "Run U-Boot in 32/64-bit mode"
	default X86_RUN_32BIT
	help
	  U-Boot can be built as a 32-bit binary which runs in 32-bit mode
	  even on 64-bit machines. In this case SPL is not used, and U-Boot
	  runs directly from the reset vector (via 16-bit start-up).

	  Alternatively it can be run as a 64-bit binary, thus requiring a
	  64-bit machine. In this case SPL runs in 32-bit mode (via 16-bit
	  start-up) then jumps to U-Boot in 64-bit mode.

	  For now, 32-bit mode is recommended, as 64-bit is still
	  experimental and is missing a lot of features.

config X86_RUN_32BIT
	bool "32-bit"
	help
	  Build U-Boot as a 32-bit binary with no SPL. This is the currently
	  supported normal setup. U-Boot will stay in 32-bit mode even on
	  64-bit machines. When booting a 64-bit kernel, U-Boot will switch
	  to 64-bit just before starting the kernel. Only the bottom 4GB of
	  memory can be accessed through normal means, although
	  arch_phys_memset() can be used for basic access to other memory.

config X86_RUN_64BIT
	bool "64-bit"
	select X86_64
	select SUPPORT_SPL
	select SPL
	select SPL_SEPARATE_BSS
	help
	  Build U-Boot as a 64-bit binary with a 32-bit SPL. This is
	  experimental and many features are missing. U-Boot SPL starts up,
	  runs through the 16-bit and 32-bit init, then switches to 64-bit
	  mode and jumps to U-Boot proper.

endchoice

config X86_64
	bool

config SPL_X86_64
	bool
	depends on SPL

choice
	prompt "Mainboard vendor"
	default VENDOR_EMULATION

config VENDOR_ADVANTECH
	bool "advantech"

config VENDOR_CONGATEC
	bool "congatec"

config VENDOR_COREBOOT
	bool "coreboot"

config VENDOR_DFI
	bool "dfi"

config VENDOR_EFI
	bool "efi"

config VENDOR_EMULATION
	bool "emulation"

config VENDOR_GOOGLE
	bool "Google"

config VENDOR_INTEL
	bool "Intel"

endchoice

# subarchitectures-specific options below
config INTEL_MID
	bool "Intel MID platform support"
	select REGMAP
	select SYSCON
	help
	  Select to build a U-Boot capable of supporting Intel MID
	  (Mobile Internet Device) platform systems which do not have
	  the PCI legacy interfaces.

	  If you are building for a PC class system say N here.

	  Intel MID platforms are based on an Intel processor and
	  chipset which consume less power than most of the x86
	  derivatives.

# board-specific options below
source "board/advantech/Kconfig"
source "board/congatec/Kconfig"
source "board/coreboot/Kconfig"
source "board/dfi/Kconfig"
source "board/efi/Kconfig"
source "board/emulation/Kconfig"
source "board/google/Kconfig"
source "board/intel/Kconfig"

# platform-specific options below
source "arch/x86/cpu/baytrail/Kconfig"
source "arch/x86/cpu/braswell/Kconfig"
source "arch/x86/cpu/broadwell/Kconfig"
source "arch/x86/cpu/coreboot/Kconfig"
source "arch/x86/cpu/ivybridge/Kconfig"
source "arch/x86/cpu/qemu/Kconfig"
source "arch/x86/cpu/quark/Kconfig"
source "arch/x86/cpu/queensbay/Kconfig"
source "arch/x86/cpu/tangier/Kconfig"

# architecture-specific options below

config AHCI
	default y

config SYS_MALLOC_F_LEN
	default 0x800

config RAMBASE
	hex
	default 0x100000

config XIP_ROM_SIZE
	hex
	depends on X86_RESET_VECTOR
	default ROM_SIZE

config CPU_ADDR_BITS
	int
	default 36

config HPET_ADDRESS
	hex
	default 0xfed00000 if !HPET_ADDRESS_OVERRIDE

config SMM_TSEG
	bool
	default n

config SMM_TSEG_SIZE
	hex

config X86_RESET_VECTOR
	bool
	default n
	select BINMAN

# The following options control where the 16-bit and 32-bit init lies
# If SPL is enabled then it normally holds this init code, and U-Boot proper
# is normally a 64-bit build.
#
# The 16-bit init refers to the reset vector and the small amount of code to
# get the processor into 32-bit mode. It may be in SPL or in U-Boot proper,
# or missing altogether if U-Boot is started from EFI or coreboot.
#
# The 32-bit init refers to processor init, running binary blobs including
# FSP, setting up interrupts and anything else that needs to be done in
# 32-bit code. It is normally in the same place as 16-bit init if that is
# enabled (i.e. they are both in SPL, or both in U-Boot proper).
config X86_16BIT_INIT
	bool
	depends on X86_RESET_VECTOR
	default y if X86_RESET_VECTOR && !SPL
	help
	  This is enabled when 16-bit init is in U-Boot proper

config SPL_X86_16BIT_INIT
	bool
	depends on X86_RESET_VECTOR
	default y if X86_RESET_VECTOR && SPL
	help
	  This is enabled when 16-bit init is in SPL

config X86_32BIT_INIT
	bool
	depends on X86_RESET_VECTOR
	default y if X86_RESET_VECTOR && !SPL
	help
	  This is enabled when 32-bit init is in U-Boot proper

config SPL_X86_32BIT_INIT
	bool
	depends on X86_RESET_VECTOR
	default y if X86_RESET_VECTOR && SPL
	help
	  This is enabled when 32-bit init is in SPL

config RESET_SEG_START
	hex
	depends on X86_RESET_VECTOR
	default 0xffff0000

config RESET_SEG_SIZE
	hex
	depends on X86_RESET_VECTOR
	default 0x10000

config RESET_VEC_LOC
	hex
	depends on X86_RESET_VECTOR
	default 0xfffffff0

config SYS_X86_START16
	hex
	depends on X86_RESET_VECTOR
	default 0xfffff800

config X86_LOAD_FROM_32_BIT
	bool "Boot from a 32-bit program"
	help
	  Define this to boot U-Boot from a 32-bit program which sets
	  the GDT differently. This can be used to boot directly from
	  any stage of coreboot, for example, bypassing the normal
	  payload-loading feature.

config BOARD_ROMSIZE_KB_512
	bool
config BOARD_ROMSIZE_KB_1024
	bool
config BOARD_ROMSIZE_KB_2048
	bool
config BOARD_ROMSIZE_KB_4096
	bool
config BOARD_ROMSIZE_KB_8192
	bool
config BOARD_ROMSIZE_KB_16384
	bool

choice
	prompt "ROM chip size"
	depends on X86_RESET_VECTOR
	default UBOOT_ROMSIZE_KB_512 if BOARD_ROMSIZE_KB_512
	default UBOOT_ROMSIZE_KB_1024 if BOARD_ROMSIZE_KB_1024
	default UBOOT_ROMSIZE_KB_2048 if BOARD_ROMSIZE_KB_2048
	default UBOOT_ROMSIZE_KB_4096 if BOARD_ROMSIZE_KB_4096
	default UBOOT_ROMSIZE_KB_8192 if BOARD_ROMSIZE_KB_8192
	default UBOOT_ROMSIZE_KB_16384 if BOARD_ROMSIZE_KB_16384
	help
	  Select the size of the ROM chip you intend to flash U-Boot on.

	  The build system will take care of creating a u-boot.rom file
	  of the matching size.

config UBOOT_ROMSIZE_KB_512
	bool "512 KB"
	help
	  Choose this option if you have a 512 KB ROM chip.

config UBOOT_ROMSIZE_KB_1024
	bool "1024 KB (1 MB)"
	help
	  Choose this option if you have a 1024 KB (1 MB) ROM chip.

config UBOOT_ROMSIZE_KB_2048
	bool "2048 KB (2 MB)"
	help
	  Choose this option if you have a 2048 KB (2 MB) ROM chip.

config UBOOT_ROMSIZE_KB_4096
	bool "4096 KB (4 MB)"
	help
	  Choose this option if you have a 4096 KB (4 MB) ROM chip.

config UBOOT_ROMSIZE_KB_8192
	bool "8192 KB (8 MB)"
	help
	  Choose this option if you have a 8192 KB (8 MB) ROM chip.

config UBOOT_ROMSIZE_KB_16384
	bool "16384 KB (16 MB)"
	help
	  Choose this option if you have a 16384 KB (16 MB) ROM chip.

endchoice

# Map the config names to an integer (KB).
config UBOOT_ROMSIZE_KB
	int
	default 512 if UBOOT_ROMSIZE_KB_512
	default 1024 if UBOOT_ROMSIZE_KB_1024
	default 2048 if UBOOT_ROMSIZE_KB_2048
	default 4096 if UBOOT_ROMSIZE_KB_4096
	default 8192 if UBOOT_ROMSIZE_KB_8192
	default 16384 if UBOOT_ROMSIZE_KB_16384

# Map the config names to a hex value (bytes).
config ROM_SIZE
	hex
	default 0x80000 if UBOOT_ROMSIZE_KB_512
	default 0x100000 if UBOOT_ROMSIZE_KB_1024
	default 0x200000 if UBOOT_ROMSIZE_KB_2048
	default 0x400000 if UBOOT_ROMSIZE_KB_4096
	default 0x800000 if UBOOT_ROMSIZE_KB_8192
	default 0xc00000 if UBOOT_ROMSIZE_KB_12288
	default 0x1000000 if UBOOT_ROMSIZE_KB_16384

config HAVE_INTEL_ME
	bool "Platform requires Intel Management Engine"
	help
	  Newer higher-end devices have an Intel Management Engine (ME)
	  which is a very large binary blob (typically 1.5MB) which is
	  required for the platform to work. This enforces a particular
	  SPI flash format. You will need to supply the me.bin file in
	  your board directory.

config X86_RAMTEST
	bool "Perform a simple RAM test after SDRAM initialisation"
	help
	  If there is something wrong with SDRAM then the platform will
	  often crash within U-Boot or the kernel. This option enables a
	  very simple RAM test that quickly checks whether the SDRAM seems
	  to work correctly. It is not exhaustive but can save time by
	  detecting obvious failures.

config FLASH_DESCRIPTOR_FILE
	string "Flash descriptor binary filename"
	depends on HAVE_INTEL_ME
	default "descriptor.bin"
	help
	  The filename of the file to use as flash descriptor in the
	  board directory.

config INTEL_ME_FILE
	string "Intel Management Engine binary filename"
	depends on HAVE_INTEL_ME
	default "me.bin"
	help
	  The filename of the file to use as Intel Management Engine in the
	  board directory.

config HAVE_FSP
	bool "Add an Firmware Support Package binary"
	depends on !EFI
	help
	  Select this option to add an Firmware Support Package binary to
	  the resulting U-Boot image. It is a binary blob which U-Boot uses
	  to set up SDRAM and other chipset specific initialization.

	  Note: Without this binary U-Boot will not be able to set up its
	  SDRAM so will not boot.

config FSP_FILE
	string "Firmware Support Package binary filename"
	depends on HAVE_FSP
	default "fsp.bin"
	help
	  The filename of the file to use as Firmware Support Package binary
	  in the board directory.

config FSP_ADDR
	hex "Firmware Support Package binary location"
	depends on HAVE_FSP
	default 0xfffc0000
	help
	  FSP is not Position Independent Code (PIC) and the whole FSP has to
	  be rebased if it is placed at a location which is different from the
	  perferred base address specified during the FSP build. Use Intel's
	  Binary Configuration Tool (BCT) to do the rebase.

	  The default base address of 0xfffc0000 indicates that the binary must
	  be located at offset 0xc0000 from the beginning of a 1MB flash device.

config FSP_TEMP_RAM_ADDR
	hex
	depends on HAVE_FSP
	default 0x2000000
	help
	  Stack top address which is used in fsp_init() after DRAM is ready and
	  CAR is disabled.

config FSP_SYS_MALLOC_F_LEN
	hex
	depends on HAVE_FSP
	default 0x100000
	help
	  Additional size of malloc() pool before relocation.

config FSP_USE_UPD
	bool
	depends on HAVE_FSP
	default y
	help
	  Most FSPs use UPD data region for some FSP customization. But there
	  are still some FSPs that might not even have UPD. For such FSPs,
	  override this to n in their platform Kconfig files.

config FSP_BROKEN_HOB
	bool
	depends on HAVE_FSP
	help
	  Indicate some buggy FSPs that does not report memory used by FSP
	  itself as reserved in the resource descriptor HOB. Select this to
	  tell U-Boot to do some additional work to ensure U-Boot relocation
	  do not overwrite the important boot service data which is used by
	  FSP, otherwise the subsequent call to fsp_notify() will fail.

config ENABLE_MRC_CACHE
	bool "Enable MRC cache"
	depends on !EFI && !SYS_COREBOOT
	help
	  Enable this feature to cause MRC data to be cached in NV storage
	  to be used for speeding up boot time on future reboots and/or
	  power cycles.

	  For platforms that use Intel FSP for the memory initialization,
	  please check FSP output HOB via U-Boot command 'fsp hob' to see
	  if there is FSP_NON_VOLATILE_STORAGE_HOB_GUID (asm/fsp/fsp_hob.h).
	  If such GUID does not exist, MRC cache is not avaiable on such
	  platform (eg: Intel Queensbay), which means selecting this option
	  here does not make any difference.

config HAVE_MRC
	bool "Add a System Agent binary"
	depends on !HAVE_FSP
	help
	  Select this option to add a System Agent binary to
	  the resulting U-Boot image. MRC stands for Memory Reference Code.
	  It is a binary blob which U-Boot uses to set up SDRAM.

	  Note: Without this binary U-Boot will not be able to set up its
	  SDRAM so will not boot.

config CACHE_MRC_BIN
	bool
	depends on HAVE_MRC
	default n
	help
	  Enable caching for the memory reference code binary. This uses an
	  MTRR (memory type range register) to turn on caching for the section
	  of SPI flash that contains the memory reference code. This makes
	  SDRAM init run faster.

config CACHE_MRC_SIZE_KB
	int
	depends on HAVE_MRC
	default 512
	help
	  Sets the size of the cached area for the memory reference code.
	  This ends at the end of SPI flash (address 0xffffffff) and is
	  measured in KB. Typically this is set to 512, providing for 0.5MB
	  of cached space.

config DCACHE_RAM_BASE
	hex
	depends on HAVE_MRC
	help
	  Sets the base of the data cache area in memory space. This is the
	  start address of the cache-as-RAM (CAR) area and the address varies
	  depending on the CPU. Once CAR is set up, read/write memory becomes
	  available at this address and can be used temporarily until SDRAM
	  is working.

config DCACHE_RAM_SIZE
	hex
	depends on HAVE_MRC
	default 0x40000
	help
	  Sets the total size of the data cache area in memory space. This
	  sets the size of the cache-as-RAM (CAR) area. Note that much of the
	  CAR space is required by the MRC. The CAR space available to U-Boot
	  is normally at the start and typically extends to 1/4 or 1/2 of the
	  available size.

config DCACHE_RAM_MRC_VAR_SIZE
	hex
	depends on HAVE_MRC
	help
	  This is the amount of CAR (Cache as RAM) reserved for use by the
	  memory reference code. This depends on the implementation of the
	  memory reference code and must be set correctly or the board will
	  not boot.

config HAVE_REFCODE
        bool "Add a Reference Code binary"
        help
          Select this option to add a Reference Code binary to the resulting
          U-Boot image. This is an Intel binary blob that handles system
          initialisation, in this case the PCH and System Agent.

          Note: Without this binary (on platforms that need it such as
          broadwell) U-Boot will be missing some critical setup steps.
          Various peripherals may fail to work.

config SMP
	bool "Enable Symmetric Multiprocessing"
	default n
	help
	  Enable use of more than one CPU in U-Boot and the Operating System
	  when loaded. Each CPU will be started up and information can be
	  obtained using the 'cpu' command. If this option is disabled, then
	  only one CPU will be enabled regardless of the number of CPUs
	  available.

config MAX_CPUS
	int "Maximum number of CPUs permitted"
	depends on SMP
	default 4
	help
	  When using multi-CPU chips it is possible for U-Boot to start up
	  more than one CPU. The stack memory used by all of these CPUs is
	  pre-allocated so at present U-Boot wants to know the maximum
	  number of CPUs that may be present. Set this to at least as high
	  as the number of CPUs in your system (it uses about 4KB of RAM for
	  each CPU).

config AP_STACK_SIZE
	hex
	depends on SMP
	default 0x1000
	help
	  Each additional CPU started by U-Boot requires its own stack. This
	  option sets the stack size used by each CPU and directly affects
	  the memory used by this initialisation process. Typically 4KB is
	  enough space.

config CPU_INTEL_TURBO_NOT_PACKAGE_SCOPED
	bool
	help
	  This option indicates that the turbo mode setting is not package
	  scoped. i.e. turbo_enable() needs to be called on not just the
	  bootstrap processor (BSP).

config HAVE_VGA_BIOS
	bool "Add a VGA BIOS image"
	help
	  Select this option if you have a VGA BIOS image that you would
	  like to add to your ROM.

config VGA_BIOS_FILE
	string "VGA BIOS image filename"
	depends on HAVE_VGA_BIOS
	default "vga.bin"
	help
	  The filename of the VGA BIOS image in the board directory.

config VGA_BIOS_ADDR
	hex "VGA BIOS image location"
	depends on HAVE_VGA_BIOS
	default 0xfff90000
	help
	  The location of VGA BIOS image in the SPI flash. For example, base
	  address of 0xfff90000 indicates that the image will be put at offset
	  0x90000 from the beginning of a 1MB flash device.

config HAVE_VBT
	bool "Add a Video BIOS Table (VBT) image"
	depends on HAVE_FSP
	help
	  Select this option if you have a Video BIOS Table (VBT) image that
	  you would like to add to your ROM. This is normally required if you
	  are using an Intel FSP firmware that is complaint with spec 1.1 or
	  later to initialize the integrated graphics device (IGD).

	  Video BIOS Table, or VBT, provides platform and board specific
	  configuration information to the driver that is not discoverable
	  or available through other means. By other means the most used
	  method here is to read EDID table from the attached monitor, over
	  Display Data Channel (DDC) using two pin I2C serial interface. VBT
	  configuration is related to display hardware and is available via
	  the ACPI OpRegion or, on older systems, in the PCI ROM (Option ROM).

config VBT_FILE
	string "Video BIOS Table (VBT) image filename"
	depends on HAVE_VBT
	default "vbt.bin"
	help
	  The filename of the file to use as Video BIOS Table (VBT) image
	  in the board directory.

config VBT_ADDR
	hex "Video BIOS Table (VBT) image location"
	depends on HAVE_VBT
	default 0xfff90000
	help
	  The location of Video BIOS Table (VBT) image in the SPI flash. For
	  example, base address of 0xfff90000 indicates that the image will
	  be put at offset 0x90000 from the beginning of a 1MB flash device.

config VIDEO_FSP
	bool "Enable FSP framebuffer driver support"
	depends on HAVE_VBT && DM_VIDEO
	help
	  Turn on this option to enable a framebuffer driver when U-Boot is
	  using Video BIOS Table (VBT) image for FSP firmware to initialize
	  the integrated graphics device.

config ROM_TABLE_ADDR
	hex
	default 0xf0000
	help
	  All x86 tables happen to like the address range from 0x0f0000
	  to 0x100000. We use 0xf0000 as the starting address to store
	  those tables, including PIRQ routing table, Multi-Processor
	  table and ACPI table.

config ROM_TABLE_SIZE
	hex
	default 0x10000

menu "System tables"
	depends on !EFI && !SYS_COREBOOT

config GENERATE_PIRQ_TABLE
	bool "Generate a PIRQ table"
	default n
	help
	  Generate a PIRQ routing table for this board. The PIRQ routing table
	  is generated by U-Boot in the system memory from 0xf0000 to 0xfffff
	  at every 16-byte boundary with a PCI IRQ routing signature ("$PIR").
	  It specifies the interrupt router information as well how all the PCI
	  devices' interrupt pins are wired to PIRQs.

config GENERATE_SFI_TABLE
	bool "Generate a SFI (Simple Firmware Interface) table"
	help
	  The Simple Firmware Interface (SFI) provides a lightweight method
	  for platform firmware to pass information to the operating system
	  via static tables in memory.  Kernel SFI support is required to
	  boot on SFI-only platforms.  If you have ACPI tables then these are
	  used instead.

	  U-Boot writes this table in write_sfi_table() just before booting
	  the OS.

	  For more information, see http://simplefirmware.org

config GENERATE_MP_TABLE
	bool "Generate an MP (Multi-Processor) table"
	default n
	help
	  Generate an MP (Multi-Processor) table for this board. The MP table
	  provides a way for the operating system to support for symmetric
	  multiprocessing as well as symmetric I/O interrupt handling with
	  the local APIC and I/O APIC.

config GENERATE_ACPI_TABLE
	bool "Generate an ACPI (Advanced Configuration and Power Interface) table"
	default n
	select QFW if QEMU
	help
	  The Advanced Configuration and Power Interface (ACPI) specification
	  provides an open standard for device configuration and management
	  by the operating system. It defines platform-independent interfaces
	  for configuration and power management monitoring.

endmenu

config HAVE_ACPI_RESUME
	bool "Enable ACPI S3 resume"
	select ENABLE_MRC_CACHE
	help
	  Select this to enable ACPI S3 resume. S3 is an ACPI-defined sleeping
	  state where all system context is lost except system memory. U-Boot
	  is responsible for restoring the machine state as it was before sleep.
	  It needs restore the memory controller, without overwriting memory
	  which is not marked as reserved. For the peripherals which lose their
	  registers, U-Boot needs to write the original value. When everything
	  is done, U-Boot needs to find out the wakeup vector provided by OSes
	  and jump there.

config S3_VGA_ROM_RUN
	bool "Re-run VGA option ROMs on S3 resume"
	depends on HAVE_ACPI_RESUME
	help
	  Execute VGA option ROMs in U-Boot when resuming from S3. Normally
	  this is needed when graphics console is being used in the kernel.

	  Turning it off can reduce some resume time, but be aware that your
	  graphics console won't work without VGA options ROMs. Set it to N
	  if your kernel is only on a serial console.

config STACK_SIZE
	hex
	depends on HAVE_ACPI_RESUME
	default 0x1000
	help
	  Estimated U-Boot's runtime stack size that needs to be reserved
	  during an ACPI S3 resume.

config MAX_PIRQ_LINKS
	int
	default 8
	help
	  This variable specifies the number of PIRQ interrupt links which are
	  routable. On most older chipsets, this is 4, PIRQA through PIRQD.
	  Some newer chipsets offer more than four links, commonly up to PIRQH.

config IRQ_SLOT_COUNT
	int
	default 128
	help
	  U-Boot can support up to 254 IRQ slot info in the PIRQ routing table
	  which in turns forms a table of exact 4KiB. The default value 128
	  should be enough for most boards. If this does not fit your board,
	  change it according to your needs.

config PCIE_ECAM_BASE
	hex
	default 0xe0000000
	help
	  This is the memory-mapped address of PCI configuration space, which
	  is only available through the Enhanced Configuration Access
	  Mechanism (ECAM) with PCI Express. It can be set up almost
	  anywhere. Before it is set up, it is possible to access PCI
	  configuration space through I/O access, but memory access is more
	  convenient. Using this, PCI can be scanned and configured. This
	  should be set to a region that does not conflict with memory
	  assigned to PCI devices - i.e. the memory and prefetch regions, as
	  passed to pci_set_region().

config PCIE_ECAM_SIZE
	hex
	default 0x10000000
	help
	  This is the size of memory-mapped address of PCI configuration space,
	  which is only available through the Enhanced Configuration Access
	  Mechanism (ECAM) with PCI Express. Each bus consumes 1 MiB memory,
	  so a default 0x10000000 size covers all of the 256 buses which is the
	  maximum number of PCI buses as defined by the PCI specification.

config I8259_PIC
	bool
	default y
	help
	  Intel 8259 ISA compatible chipset incorporates two 8259 (master and
	  slave) interrupt controllers. Include this to have U-Boot set up
	  the interrupt correctly.

config PINCTRL_ICH6
	bool
	help
	  Intel ICH6 compatible chipset pinctrl driver. It needs to work
	  together with the ICH6 compatible gpio driver.

config I8254_TIMER
	bool
	default y
	help
	  Intel 8254 timer contains three counters which have fixed uses.
	  Include this to have U-Boot set up the timer correctly.

config SEABIOS
	bool "Support booting SeaBIOS"
	help
	  SeaBIOS is an open source implementation of a 16-bit X86 BIOS.
	  It can run in an emulator or natively on X86 hardware with the use
	  of coreboot/U-Boot. By turning on this option, U-Boot prepares
	  all the configuration tables that are necessary to boot SeaBIOS.

	  Check http://www.seabios.org/SeaBIOS for details.

config HIGH_TABLE_SIZE
	hex "Size of configuration tables which reside in high memory"
	default 0x10000
	depends on SEABIOS
	help
	  SeaBIOS itself resides in E seg and F seg, where U-Boot puts all
	  configuration tables like PIRQ/MP/ACPI. To avoid conflicts, U-Boot
	  puts a copy of configuration tables in high memory region which
	  is reserved on the stack before relocation. The region size is
	  determined by this option.

	  Increse it if the default size does not fit the board's needs.
	  This is most likely due to a large ACPI DSDT table is used.

source "arch/x86/lib/efi/Kconfig"

endmenu