arch/powerpc/Kconfig

# For a description of the syntax of this configuration file,
# see Documentation/kbuild/kconfig-language.txt.
#

mainmenu "Linux/PowerPC Kernel Configuration"

config PPC64
	bool "64-bit kernel"
	default n
	help
	  This option selects whether a 32-bit or a 64-bit kernel
	  will be built.

config PPC_PM_NEEDS_RTC_LIB
	bool
	select RTC_LIB
	default y if PM

config PPC32
	bool
	default y if !PPC64

config 64BIT
	bool
	default y if PPC64

config PPC_MERGE
	def_bool y

config MMU
	bool
	default y

config GENERIC_HARDIRQS
	bool
	default y

config IRQ_PER_CPU
	bool
	default y

config RWSEM_GENERIC_SPINLOCK
	bool

config RWSEM_XCHGADD_ALGORITHM
	bool
	default y

config ARCH_HAS_ILOG2_U32
	bool
	default y

config ARCH_HAS_ILOG2_U64
	bool
	default y if 64BIT

config GENERIC_HWEIGHT
	bool
	default y

config GENERIC_CALIBRATE_DELAY
	bool
	default y

config GENERIC_FIND_NEXT_BIT
	bool
	default y

config PPC
	bool
	default y

config EARLY_PRINTK
	bool
	default y

config COMPAT
	bool
	default y if PPC64

config SYSVIPC_COMPAT
	bool
	depends on COMPAT && SYSVIPC
	default y

# All PPC32s use generic nvram driver through ppc_md
config GENERIC_NVRAM
	bool
	default y if PPC32

config SCHED_NO_NO_OMIT_FRAME_POINTER
	bool
	default y

config ARCH_MAY_HAVE_PC_FDC
	bool
	default !PPC_PSERIES || PCI

config PPC_OF
	def_bool y

config PPC_UDBG_16550
	bool
	default n

config GENERIC_TBSYNC
	bool
	default y if PPC32 && SMP
	default n

config AUDIT_ARCH
	bool
	default y

config GENERIC_BUG
	bool
	default y
	depends on BUG

config SYS_SUPPORTS_APM_EMULATION
	bool

config DEFAULT_UIMAGE
	bool
	help
	  Used to allow a board to specify it wants a uImage built by default
	default n

config PPC64_SWSUSP
	bool
	depends on PPC64 && (BROKEN || (PPC_PMAC64 && EXPERIMENTAL))
	default y

menu "Processor support"
choice
	prompt "Processor Type"
	depends on PPC32
	default 6xx

config CLASSIC32
	bool "52xx/6xx/7xx/74xx"
	select PPC_FPU
	select 6xx
	help
	  There are four families of PowerPC chips supported.  The more common
	  types (601, 603, 604, 740, 750, 7400), the Motorola embedded
	  versions (821, 823, 850, 855, 860, 52xx, 82xx, 83xx), the AMCC
	  embedded versions (403 and 405) and the high end 64 bit Power
	  processors (POWER 3, POWER4, and IBM PPC970 also known as G5).

	  This option is the catch-all for 6xx types, including some of the
	  embedded versions.  Unless there is see an option for the specific
	  chip family you are using, you want this option.
	  
	  You do not want this if you are building a kernel for a 64 bit
	  IBM RS/6000 or an Apple G5, choose 6xx.
	  
	  If unsure, select this option
	  
	  Note that the kernel runs in 32-bit mode even on 64-bit chips.

config PPC_82xx
	bool "Freescale 82xx"
	select 6xx
	select PPC_FPU

config PPC_83xx
	bool "Freescale 83xx"
	select 6xx
	select FSL_SOC
	select 83xx
	select PPC_FPU
	select WANT_DEVICE_TREE

config PPC_85xx
	bool "Freescale 85xx"
	select E500
	select FSL_SOC
	select 85xx
	select WANT_DEVICE_TREE

config PPC_86xx
	bool "Freescale 86xx"
	select 6xx
	select FSL_SOC
	select FSL_PCIE
	select PPC_FPU
	select ALTIVEC
	help
	  The Freescale E600 SoCs have 74xx cores.

config PPC_8xx
	bool "Freescale 8xx"
	select FSL_SOC
	select 8xx

config 40x
	bool "AMCC 40x"
	select PPC_DCR_NATIVE

config 44x
	bool "AMCC 44x"
	select PPC_DCR_NATIVE
	select WANT_DEVICE_TREE

config E200
	bool "Freescale e200"

endchoice

config POWER4_ONLY
	bool "Optimize for POWER4"
	depends on PPC64
	default n
	---help---
	  Cause the compiler to optimize for POWER4/POWER5/PPC970 processors.
	  The resulting binary will not work on POWER3 or RS64 processors
	  when compiled with binutils 2.15 or later.

config POWER3
	bool
	depends on PPC64
	default y if !POWER4_ONLY

config POWER4
	depends on PPC64
	def_bool y

config 6xx
	bool

# this is temp to handle compat with arch=ppc
config 8xx
	bool

# this is temp to handle compat with arch=ppc
config 83xx
	bool

# this is temp to handle compat with arch=ppc
config 85xx
	bool

config E500
	bool

config PPC_FPU
	bool
	default y if PPC64

config PPC_DCR_NATIVE
	bool
	default n

config PPC_DCR_MMIO
	bool
	default n

config PPC_DCR
	bool
	depends on PPC_DCR_NATIVE || PPC_DCR_MMIO
	default y

config PPC_OF_PLATFORM_PCI
	bool
	depends on PPC64 # not supported on 32 bits yet
	default n

config 4xx
	bool
	depends on 40x || 44x
	default y

config BOOKE
	bool
	depends on E200 || E500 || 44x
	default y

config FSL_BOOKE
	bool
	depends on E200 || E500
	default y

config PTE_64BIT
	bool
	depends on 44x || E500
	default y if 44x
	default y if E500 && PHYS_64BIT

config PHYS_64BIT
	bool 'Large physical address support' if E500
	depends on 44x || E500
	select RESOURCES_64BIT
	default y if 44x
	---help---
	  This option enables kernel support for larger than 32-bit physical
	  addresses.  This features is not be available on all e500 cores.

	  If in doubt, say N here.

config ALTIVEC
	bool "AltiVec Support"
	depends on CLASSIC32 || POWER4
	---help---
	  This option enables kernel support for the Altivec extensions to the
	  PowerPC processor. The kernel currently supports saving and restoring
	  altivec registers, and turning on the 'altivec enable' bit so user
	  processes can execute altivec instructions.

	  This option is only usefully if you have a processor that supports
	  altivec (G4, otherwise known as 74xx series), but does not have
	  any affect on a non-altivec cpu (it does, however add code to the
	  kernel).

	  If in doubt, say Y here.

config SPE
	bool "SPE Support"
	depends on E200 || E500
	default y
	---help---
	  This option enables kernel support for the Signal Processing
	  Extensions (SPE) to the PowerPC processor. The kernel currently
	  supports saving and restoring SPE registers, and turning on the
	  'spe enable' bit so user processes can execute SPE instructions.

	  This option is only useful if you have a processor that supports
	  SPE (e500, otherwise known as 85xx series), but does not have any
	  effect on a non-spe cpu (it does, however add code to the kernel).

	  If in doubt, say Y here.

config PPC_STD_MMU
	bool
	depends on 6xx || POWER3 || POWER4 || PPC64
	default y

config PPC_STD_MMU_32
	def_bool y
	depends on PPC_STD_MMU && PPC32

config PPC_MM_SLICES
	bool
	default y if HUGETLB_PAGE
	default n

config VIRT_CPU_ACCOUNTING
	bool "Deterministic task and CPU time accounting"
	depends on PPC64
	default y
	help
	  Select this option to enable more accurate task and CPU time
	  accounting.  This is done by reading a CPU counter on each
	  kernel entry and exit and on transitions within the kernel
	  between system, softirq and hardirq state, so there is a
	  small performance impact.  This also enables accounting of
	  stolen time on logically-partitioned systems running on
	  IBM POWER5-based machines.

	  If in doubt, say Y here.

config SMP
	depends on PPC_STD_MMU
	bool "Symmetric multi-processing support"
	---help---
	  This enables support for systems with more than one CPU. If you have
	  a system with only one CPU, say N. If you have a system with more
	  than one CPU, say Y.  Note that the kernel does not currently
	  support SMP machines with 603/603e/603ev or PPC750 ("G3") processors
	  since they have inadequate hardware support for multiprocessor
	  operation.

	  If you say N here, the kernel will run on single and multiprocessor
	  machines, but will use only one CPU of a multiprocessor machine. If
	  you say Y here, the kernel will run on single-processor machines.
	  On a single-processor machine, the kernel will run faster if you say
	  N here.

	  If you don't know what to do here, say N.

config NR_CPUS
	int "Maximum number of CPUs (2-128)"
	range 2 128
	depends on SMP
	default "32" if PPC64
	default "4"

config NOT_COHERENT_CACHE
	bool
	depends on 4xx || 8xx || E200
	default y

config CONFIG_CHECK_CACHE_COHERENCY
	bool
endmenu

source "init/Kconfig"

source "arch/powerpc/platforms/Kconfig"

menu "Kernel options"

config HIGHMEM
	bool "High memory support"
	depends on PPC32

source kernel/Kconfig.hz
source kernel/Kconfig.preempt
source "fs/Kconfig.binfmt"

# We optimistically allocate largepages from the VM, so make the limit
# large enough (16MB). This badly named config option is actually
# max order + 1
config FORCE_MAX_ZONEORDER
	int
	depends on PPC64
	default "9" if PPC_64K_PAGES
	default "13"

config MATH_EMULATION
	bool "Math emulation"
	depends on 4xx || 8xx || E200 || PPC_MPC832x || E500
	---help---
	  Some PowerPC chips designed for embedded applications do not have
	  a floating-point unit and therefore do not implement the
	  floating-point instructions in the PowerPC instruction set.  If you
	  say Y here, the kernel will include code to emulate a floating-point
	  unit, which will allow programs that use floating-point
	  instructions to run.

config IOMMU_VMERGE
	bool "Enable IOMMU virtual merging (EXPERIMENTAL)"
	depends on EXPERIMENTAL && PPC64
	default n
	help
	  Cause IO segments sent to a device for DMA to be merged virtually
	  by the IOMMU when they happen to have been allocated contiguously.
	  This doesn't add pressure to the IOMMU allocator. However, some
	  drivers don't support getting large merged segments coming back
	  from *_map_sg(). Say Y if you know the drivers you are using are
	  properly handling this case.

config HOTPLUG_CPU
	bool "Support for enabling/disabling CPUs"
	depends on SMP && HOTPLUG && EXPERIMENTAL && (PPC_PSERIES || PPC_PMAC)
	---help---
	  Say Y here to be able to disable and re-enable individual
	  CPUs at runtime on SMP machines.

	  Say N if you are unsure.

config ARCH_ENABLE_MEMORY_HOTPLUG
	def_bool y

config KEXEC
	bool "kexec system call (EXPERIMENTAL)"
	depends on (PPC_PRPMC2800 || PPC_MULTIPLATFORM) && EXPERIMENTAL
	help
	  kexec is a system call that implements the ability to shutdown your
	  current kernel, and to start another kernel.  It is like a reboot
	  but it is independent of the system firmware.   And like a reboot
	  you can start any kernel with it, not just Linux.

	  The name comes from the similarity to the exec system call.

	  It is an ongoing process to be certain the hardware in a machine
	  is properly shutdown, so do not be surprised if this code does not
	  initially work for you.  It may help to enable device hotplugging
	  support.  As of this writing the exact hardware interface is
	  strongly in flux, so no good recommendation can be made.

config CRASH_DUMP
	bool "Build a kdump crash kernel (EXPERIMENTAL)"
	depends on PPC_MULTIPLATFORM && PPC64 && EXPERIMENTAL
	help
	  Build a kernel suitable for use as a kdump capture kernel.
	  The kernel will be linked at a different address than normal, and
	  so can only be used for Kdump.

	  Don't change this unless you know what you are doing.

config PPCBUG_NVRAM
	bool "Enable reading PPCBUG NVRAM during boot" if PPLUS || LOPEC
	default y if PPC_PREP

config IRQ_ALL_CPUS
	bool "Distribute interrupts on all CPUs by default"
	depends on SMP && !MV64360
	help
	  This option gives the kernel permission to distribute IRQs across
	  multiple CPUs.  Saying N here will route all IRQs to the first
	  CPU.  Generally saying Y is safe, although some problems have been
	  reported with SMP Power Macintoshes with this option enabled.

config NUMA
	bool "NUMA support"
	depends on PPC64
	default y if SMP && PPC_PSERIES

config NODES_SHIFT
	int
	default "4"
	depends on NEED_MULTIPLE_NODES

config ARCH_SELECT_MEMORY_MODEL
	def_bool y
	depends on PPC64

config ARCH_FLATMEM_ENABLE
	def_bool y
	depends on (PPC64 && !NUMA) || PPC32

config ARCH_SPARSEMEM_ENABLE
	def_bool y
	depends on PPC64

config ARCH_SPARSEMEM_DEFAULT
	def_bool y
	depends on (SMP && PPC_PSERIES) || PPC_PS3

config ARCH_POPULATES_NODE_MAP
	def_bool y

source "mm/Kconfig"

config ARCH_MEMORY_PROBE
	def_bool y
	depends on MEMORY_HOTPLUG

# Some NUMA nodes have memory ranges that span
# other nodes.  Even though a pfn is valid and
# between a node's start and end pfns, it may not
# reside on that node.  See memmap_init_zone()
# for details.
config NODES_SPAN_OTHER_NODES
	def_bool y
	depends on NEED_MULTIPLE_NODES

config PPC_HAS_HASH_64K
	bool
	depends on PPC64
	default n

config PPC_64K_PAGES
	bool "64k page size"
	depends on PPC64
	select PPC_HAS_HASH_64K
	help
	  This option changes the kernel logical page size to 64k. On machines
	  without processor support for 64k pages, the kernel will simulate
	  them by loading each individual 4k page on demand transparently,
	  while on hardware with such support, it will be used to map
	  normal application pages.

config SCHED_SMT
	bool "SMT (Hyperthreading) scheduler support"
	depends on PPC64 && SMP
	help
	  SMT scheduler support improves the CPU scheduler's decision making
	  when dealing with POWER5 cpus at a cost of slightly increased
	  overhead in some places. If unsure say N here.

config PROC_DEVICETREE
	bool "Support for device tree in /proc"
	depends on PROC_FS
	help
	  This option adds a device-tree directory under /proc which contains
	  an image of the device tree that the kernel copies from Open
	  Firmware or other boot firmware. If unsure, say Y here.

config CMDLINE_BOOL
	bool "Default bootloader kernel arguments"

config CMDLINE
	string "Initial kernel command string"
	depends on CMDLINE_BOOL
	default "console=ttyS0,9600 console=tty0 root=/dev/sda2"
	help
	  On some platforms, there is currently no way for the boot loader to
	  pass arguments to the kernel. For these platforms, you can supply
	  some command-line options at build time by entering them here.  In
	  most cases you will need to specify the root device here.

if !44x || BROKEN
source kernel/power/Kconfig
endif

config SECCOMP
	bool "Enable seccomp to safely compute untrusted bytecode"
	depends on PROC_FS
	default y
	help
	  This kernel feature is useful for number crunching applications
	  that may need to compute untrusted bytecode during their
	  execution. By using pipes or other transports made available to
	  the process as file descriptors supporting the read/write
	  syscalls, it's possible to isolate those applications in
	  their own address space using seccomp. Once seccomp is
	  enabled via /proc/<pid>/seccomp, it cannot be disabled
	  and the task is only allowed to execute a few safe syscalls
	  defined by each seccomp mode.

	  If unsure, say Y. Only embedded should say N here.

config WANT_DEVICE_TREE
	bool
	default n

config DEVICE_TREE
	string "Static device tree source file"
	depends on WANT_DEVICE_TREE
	help
	  This specifies the device tree source (.dts) file to be
	  compiled and included when building the bootwrapper.  If a
	  relative filename is given, then it will be relative to
	  arch/powerpc/boot/dts.  If you are not using the bootwrapper,
	  or do not need to build a dts into the bootwrapper, this
	  field is ignored.

	  For example, this is required when building a cuImage target
	  for an older U-Boot, which cannot pass a device tree itself.
	  Such a kernel will not work with a newer U-Boot that tries to
	  pass a device tree (unless you tell it not to).  If your U-Boot
	  does not mention a device tree in "help bootm", then use the
	  cuImage target and specify a device tree here.  Otherwise, use
	  the uImage target and leave this field blank.

endmenu

config ISA_DMA_API
	bool
	default y

menu "Bus options"

config ISA
	bool "Support for ISA-bus hardware"
	depends on PPC_PREP || PPC_CHRP
	select PPC_I8259
	help
	  Find out whether you have ISA slots on your motherboard.  ISA is the
	  name of a bus system, i.e. the way the CPU talks to the other stuff
	  inside your box.  If you have an Apple machine, say N here; if you
	  have an IBM RS/6000 or pSeries machine or a PReP machine, say Y.  If
	  you have an embedded board, consult your board documentation.

config ZONE_DMA
	bool
	default y

config GENERIC_ISA_DMA
	bool
	depends on PPC64 || POWER4 || 6xx && !CPM2
	default y

config PPC_INDIRECT_PCI
	bool
	depends on PCI
	default y if 40x || 44x
	default n

config PPC_INDIRECT_PCI_BE
	bool
	depends PPC_INDIRECT_PCI
	default n

config EISA
	bool

config SBUS
	bool

config FSL_SOC
	bool

config FSL_PCIE
	bool
	depends on PPC_86xx

# Yes MCA RS/6000s exist but Linux-PPC does not currently support any
config MCA
	bool

config PCI
	bool "PCI support" if 40x || CPM2 || PPC_83xx || PPC_85xx || PPC_86xx \
		|| PPC_MPC52xx || (EMBEDDED && (PPC_PSERIES || PPC_ISERIES)) \
		|| MPC7448HPC2 || PPC_PS3 || PPC_HOLLY
	default y if !40x && !CPM2 && !8xx && !APUS && !PPC_83xx \
		&& !PPC_85xx && !PPC_86xx
	default PCI_PERMEDIA if !4xx && !CPM2 && !8xx && APUS
	default PCI_QSPAN if !4xx && !CPM2 && 8xx
	select ARCH_SUPPORTS_MSI
	help
	  Find out whether your system includes a PCI bus. PCI is the name of
	  a bus system, i.e. the way the CPU talks to the other stuff inside
	  your box.  If you say Y here, the kernel will include drivers and
	  infrastructure code to support PCI bus devices.

config PCI_DOMAINS
	bool
	default PCI

config PCI_QSPAN
	bool "QSpan PCI"
	depends on !4xx && !CPM2 && 8xx
	select PPC_I8259
	help
	  Say Y here if you have a system based on a Motorola 8xx-series
	  embedded processor with a QSPAN PCI interface, otherwise say N.

config PCI_8260
	bool
	depends on PCI && 8260
	select PPC_INDIRECT_PCI
	default y

config 8260_PCI9
	bool "Enable workaround for MPC826x erratum PCI 9"
	depends on PCI_8260 && !ADS8272
	default y

choice
	prompt "IDMA channel for PCI 9 workaround"
	depends on 8260_PCI9

config 8260_PCI9_IDMA1
	bool "IDMA1"

config 8260_PCI9_IDMA2
	bool "IDMA2"

config 8260_PCI9_IDMA3
	bool "IDMA3"

config 8260_PCI9_IDMA4
	bool "IDMA4"

endchoice

source "drivers/pci/pcie/Kconfig"

source "drivers/pci/Kconfig"

source "drivers/pcmcia/Kconfig"

source "drivers/pci/hotplug/Kconfig"

endmenu

menu "Advanced setup"
	depends on PPC32

config ADVANCED_OPTIONS
	bool "Prompt for advanced kernel configuration options"
	help
	  This option will enable prompting for a variety of advanced kernel
	  configuration options.  These options can cause the kernel to not
	  work if they are set incorrectly, but can be used to optimize certain
	  aspects of kernel memory management.

	  Unless you know what you are doing, say N here.

comment "Default settings for advanced configuration options are used"
	depends on !ADVANCED_OPTIONS

config HIGHMEM_START_BOOL
	bool "Set high memory pool address"
	depends on ADVANCED_OPTIONS && HIGHMEM
	help
	  This option allows you to set the base address of the kernel virtual
	  area used to map high memory pages.  This can be useful in
	  optimizing the layout of kernel virtual memory.

	  Say N here unless you know what you are doing.

config HIGHMEM_START
	hex "Virtual start address of high memory pool" if HIGHMEM_START_BOOL
	default "0xfe000000"

config LOWMEM_SIZE_BOOL
	bool "Set maximum low memory"
	depends on ADVANCED_OPTIONS
	help
	  This option allows you to set the maximum amount of memory which
	  will be used as "low memory", that is, memory which the kernel can
	  access directly, without having to set up a kernel virtual mapping.
	  This can be useful in optimizing the layout of kernel virtual
	  memory.

	  Say N here unless you know what you are doing.

config LOWMEM_SIZE
	hex "Maximum low memory size (in bytes)" if LOWMEM_SIZE_BOOL
	default "0x30000000"

config KERNEL_START_BOOL
	bool "Set custom kernel base address"
	depends on ADVANCED_OPTIONS
	help
	  This option allows you to set the kernel virtual address at which
	  the kernel will map low memory (the kernel image will be linked at
	  this address).  This can be useful in optimizing the virtual memory
	  layout of the system.

	  Say N here unless you know what you are doing.

config KERNEL_START
	hex "Virtual address of kernel base" if KERNEL_START_BOOL
	default "0xc0000000"

config TASK_SIZE_BOOL
	bool "Set custom user task size"
	depends on ADVANCED_OPTIONS
	help
	  This option allows you to set the amount of virtual address space
	  allocated to user tasks.  This can be useful in optimizing the
	  virtual memory layout of the system.

	  Say N here unless you know what you are doing.

config TASK_SIZE
	hex "Size of user task space" if TASK_SIZE_BOOL
	default "0x80000000"

config CONSISTENT_START_BOOL
	bool "Set custom consistent memory pool address"
	depends on ADVANCED_OPTIONS && NOT_COHERENT_CACHE
	help
	  This option allows you to set the base virtual address
	  of the consistent memory pool.  This pool of virtual
	  memory is used to make consistent memory allocations.

config CONSISTENT_START
	hex "Base virtual address of consistent memory pool" if CONSISTENT_START_BOOL
	default "0xff100000" if NOT_COHERENT_CACHE

config CONSISTENT_SIZE_BOOL
	bool "Set custom consistent memory pool size"
	depends on ADVANCED_OPTIONS && NOT_COHERENT_CACHE
	help
	  This option allows you to set the size of the
	  consistent memory pool.  This pool of virtual memory
	  is used to make consistent memory allocations.

config CONSISTENT_SIZE
	hex "Size of consistent memory pool" if CONSISTENT_SIZE_BOOL
	default "0x00200000" if NOT_COHERENT_CACHE

config BOOT_LOAD_BOOL
	bool "Set the boot link/load address"
	depends on ADVANCED_OPTIONS && !PPC_MULTIPLATFORM
	help
	  This option allows you to set the initial load address of the zImage
	  or zImage.initrd file.  This can be useful if you are on a board
	  which has a small amount of memory.

	  Say N here unless you know what you are doing.

config BOOT_LOAD
	hex "Link/load address for booting" if BOOT_LOAD_BOOL
	default "0x00400000" if 40x || 8xx || 8260
	default "0x01000000" if 44x
	default "0x00800000"

config PIN_TLB
	bool "Pinned Kernel TLBs (860 ONLY)"
	depends on ADVANCED_OPTIONS && 8xx
endmenu

if PPC64
config KERNEL_START
	hex
	default "0xc000000000000000"
endif

source "net/Kconfig"

source "drivers/Kconfig"

source "fs/Kconfig"

# XXX source "arch/ppc/8xx_io/Kconfig"

# XXX source "arch/ppc/8260_io/Kconfig"

source "arch/powerpc/sysdev/qe_lib/Kconfig"

source "lib/Kconfig"

menu "Instrumentation Support"
	depends on EXPERIMENTAL

source "arch/powerpc/oprofile/Kconfig"

config KPROBES
	bool "Kprobes (EXPERIMENTAL)"
	depends on !BOOKE && !4xx && KALLSYMS && EXPERIMENTAL && MODULES
	help
	  Kprobes allows you to trap at almost any kernel address and
	  execute a callback function.  register_kprobe() establishes
	  a probepoint and specifies the callback.  Kprobes is useful
	  for kernel debugging, non-intrusive instrumentation and testing.
	  If in doubt, say "N".
endmenu

source "arch/powerpc/Kconfig.debug"

source "security/Kconfig"

config KEYS_COMPAT
	bool
	depends on COMPAT && KEYS
	default y

source "crypto/Kconfig"