xref: /openbmc/linux/arch/s390/Kconfig (revision 9e2b4be377f0d715d9d910507890f9620cc22a9d)

# SPDX-License-Identifier: GPL-2.0
config MMU
	def_bool y

config ZONE_DMA
	def_bool y

config CPU_BIG_ENDIAN
	def_bool y

config LOCKDEP_SUPPORT
	def_bool y

config STACKTRACE_SUPPORT
	def_bool y

config ARCH_HAS_ILOG2_U32
	def_bool n

config ARCH_HAS_ILOG2_U64
	def_bool n

config GENERIC_HWEIGHT
	def_bool y

config GENERIC_BUG
	def_bool y if BUG

config GENERIC_BUG_RELATIVE_POINTERS
	def_bool y

config GENERIC_LOCKBREAK
	def_bool y if PREEMPTTION

config PGSTE
	def_bool y if KVM

config ARCH_SUPPORTS_DEBUG_PAGEALLOC
	def_bool y

config AUDIT_ARCH
	def_bool y

config NO_IOPORT_MAP
	def_bool y

config PCI_QUIRKS
	def_bool n

config ARCH_SUPPORTS_UPROBES
	def_bool y

config KASAN_SHADOW_OFFSET
	hex
	depends on KASAN
	default 0x18000000000000 if KASAN_S390_4_LEVEL_PAGING
	default 0x30000000000

config S390
	def_bool y
	select ARCH_BINFMT_ELF_STATE
	select ARCH_HAS_DEVMEM_IS_ALLOWED
	select ARCH_HAS_ELF_RANDOMIZE
	select ARCH_HAS_FORTIFY_SOURCE
	select ARCH_HAS_GCOV_PROFILE_ALL
	select ARCH_HAS_GIGANTIC_PAGE
	select ARCH_HAS_KCOV
	select ARCH_HAS_MEM_ENCRYPT
	select ARCH_HAS_PTE_SPECIAL
	select ARCH_HAS_SET_MEMORY
	select ARCH_HAS_STRICT_KERNEL_RWX
	select ARCH_HAS_STRICT_MODULE_RWX
	select ARCH_HAS_SYSCALL_WRAPPER
	select ARCH_HAS_UBSAN_SANITIZE_ALL
	select ARCH_HAVE_NMI_SAFE_CMPXCHG
	select ARCH_INLINE_READ_LOCK
	select ARCH_INLINE_READ_LOCK_BH
	select ARCH_INLINE_READ_LOCK_IRQ
	select ARCH_INLINE_READ_LOCK_IRQSAVE
	select ARCH_INLINE_READ_TRYLOCK
	select ARCH_INLINE_READ_UNLOCK
	select ARCH_INLINE_READ_UNLOCK_BH
	select ARCH_INLINE_READ_UNLOCK_IRQ
	select ARCH_INLINE_READ_UNLOCK_IRQRESTORE
	select ARCH_INLINE_SPIN_LOCK
	select ARCH_INLINE_SPIN_LOCK_BH
	select ARCH_INLINE_SPIN_LOCK_IRQ
	select ARCH_INLINE_SPIN_LOCK_IRQSAVE
	select ARCH_INLINE_SPIN_TRYLOCK
	select ARCH_INLINE_SPIN_TRYLOCK_BH
	select ARCH_INLINE_SPIN_UNLOCK
	select ARCH_INLINE_SPIN_UNLOCK_BH
	select ARCH_INLINE_SPIN_UNLOCK_IRQ
	select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE
	select ARCH_INLINE_WRITE_LOCK
	select ARCH_INLINE_WRITE_LOCK_BH
	select ARCH_INLINE_WRITE_LOCK_IRQ
	select ARCH_INLINE_WRITE_LOCK_IRQSAVE
	select ARCH_INLINE_WRITE_TRYLOCK
	select ARCH_INLINE_WRITE_UNLOCK
	select ARCH_INLINE_WRITE_UNLOCK_BH
	select ARCH_INLINE_WRITE_UNLOCK_IRQ
	select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
	select ARCH_KEEP_MEMBLOCK
	select ARCH_SAVE_PAGE_KEYS if HIBERNATION
	select ARCH_STACKWALK
	select ARCH_SUPPORTS_ATOMIC_RMW
	select ARCH_SUPPORTS_NUMA_BALANCING
	select ARCH_USE_BUILTIN_BSWAP
	select ARCH_USE_CMPXCHG_LOCKREF
	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
	select ARCH_WANT_IPC_PARSE_VERSION
	select BUILDTIME_TABLE_SORT
	select CLONE_BACKWARDS2
	select DYNAMIC_FTRACE if FUNCTION_TRACER
	select GENERIC_CLOCKEVENTS
	select GENERIC_CPU_AUTOPROBE
	select GENERIC_CPU_VULNERABILITIES
	select GENERIC_FIND_FIRST_BIT
	select GENERIC_SMP_IDLE_THREAD
	select GENERIC_TIME_VSYSCALL
	select HAVE_ALIGNED_STRUCT_PAGE if SLUB
	select HAVE_ARCH_AUDITSYSCALL
	select HAVE_ARCH_JUMP_LABEL
	select HAVE_ARCH_JUMP_LABEL_RELATIVE
	select HAVE_ARCH_KASAN
	select HAVE_ARCH_KASAN_VMALLOC
	select CPU_NO_EFFICIENT_FFS if !HAVE_MARCH_Z9_109_FEATURES
	select HAVE_ARCH_SECCOMP_FILTER
	select HAVE_ARCH_SOFT_DIRTY
	select HAVE_ARCH_TRACEHOOK
	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
	select HAVE_ARCH_VMAP_STACK
	select HAVE_ASM_MODVERSIONS
	select HAVE_EBPF_JIT if PACK_STACK && HAVE_MARCH_Z196_FEATURES
	select HAVE_CMPXCHG_DOUBLE
	select HAVE_CMPXCHG_LOCAL
	select HAVE_COPY_THREAD_TLS
	select HAVE_DEBUG_KMEMLEAK
	select HAVE_DMA_CONTIGUOUS
	select HAVE_DYNAMIC_FTRACE
	select HAVE_DYNAMIC_FTRACE_WITH_REGS
	select HAVE_FAST_GUP
	select HAVE_EFFICIENT_UNALIGNED_ACCESS
	select HAVE_FENTRY
	select HAVE_FTRACE_MCOUNT_RECORD
	select HAVE_FUNCTION_GRAPH_TRACER
	select HAVE_FUNCTION_TRACER
	select HAVE_FUTEX_CMPXCHG if FUTEX
	select HAVE_GCC_PLUGINS
	select HAVE_KERNEL_BZIP2
	select HAVE_KERNEL_GZIP
	select HAVE_KERNEL_LZ4
	select HAVE_KERNEL_LZMA
	select HAVE_KERNEL_LZO
	select HAVE_KERNEL_UNCOMPRESSED
	select HAVE_KERNEL_XZ
	select HAVE_KPROBES
	select HAVE_KPROBES_ON_FTRACE
	select HAVE_KRETPROBES
	select HAVE_KVM
	select HAVE_LIVEPATCH
	select HAVE_PERF_REGS
	select HAVE_PERF_USER_STACK_DUMP
	select HAVE_MEMBLOCK_NODE_MAP
	select HAVE_MEMBLOCK_PHYS_MAP
	select MMU_GATHER_NO_GATHER
	select HAVE_MOD_ARCH_SPECIFIC
	select HAVE_NOP_MCOUNT
	select HAVE_OPROFILE
	select HAVE_PCI
	select HAVE_PERF_EVENTS
	select MMU_GATHER_RCU_TABLE_FREE
	select HAVE_REGS_AND_STACK_ACCESS_API
	select HAVE_RELIABLE_STACKTRACE
	select HAVE_RSEQ
	select HAVE_SYSCALL_TRACEPOINTS
	select HAVE_VIRT_CPU_ACCOUNTING
	select IOMMU_HELPER		if PCI
	select IOMMU_SUPPORT		if PCI
	select MODULES_USE_ELF_RELA
	select NEED_DMA_MAP_STATE	if PCI
	select NEED_SG_DMA_LENGTH	if PCI
	select OLD_SIGACTION
	select OLD_SIGSUSPEND3
	select PCI_DOMAINS		if PCI
	select PCI_MSI			if PCI
	select SPARSE_IRQ
	select SYSCTL_EXCEPTION_TRACE
	select THREAD_INFO_IN_TASK
	select TTY
	select VIRT_CPU_ACCOUNTING
	select ARCH_HAS_SCALED_CPUTIME
	select HAVE_NMI
	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
	select SWIOTLB
	select GENERIC_ALLOCATOR
	imply IMA_SECURE_AND_OR_TRUSTED_BOOT


config SCHED_OMIT_FRAME_POINTER
	def_bool y

config PGTABLE_LEVELS
	int
	default 5

source "kernel/livepatch/Kconfig"

menu "Processor type and features"

config HAVE_MARCH_Z900_FEATURES
	def_bool n

config HAVE_MARCH_Z990_FEATURES
	def_bool n
	select HAVE_MARCH_Z900_FEATURES

config HAVE_MARCH_Z9_109_FEATURES
	def_bool n
	select HAVE_MARCH_Z990_FEATURES

config HAVE_MARCH_Z10_FEATURES
	def_bool n
	select HAVE_MARCH_Z9_109_FEATURES

config HAVE_MARCH_Z196_FEATURES
	def_bool n
	select HAVE_MARCH_Z10_FEATURES

config HAVE_MARCH_ZEC12_FEATURES
	def_bool n
	select HAVE_MARCH_Z196_FEATURES

config HAVE_MARCH_Z13_FEATURES
	def_bool n
	select HAVE_MARCH_ZEC12_FEATURES

config HAVE_MARCH_Z14_FEATURES
	def_bool n
	select HAVE_MARCH_Z13_FEATURES

config HAVE_MARCH_Z15_FEATURES
	def_bool n
	select HAVE_MARCH_Z14_FEATURES

choice
	prompt "Processor type"
	default MARCH_Z196

config MARCH_Z900
	bool "IBM zSeries model z800 and z900"
	select HAVE_MARCH_Z900_FEATURES
	depends on $(cc-option,-march=z900)
	help
	  Select this to enable optimizations for model z800/z900 (2064 and
	  2066 series). This will enable some optimizations that are not
	  available on older ESA/390 (31 Bit) only CPUs.

config MARCH_Z990
	bool "IBM zSeries model z890 and z990"
	select HAVE_MARCH_Z990_FEATURES
	depends on $(cc-option,-march=z990)
	help
	  Select this to enable optimizations for model z890/z990 (2084 and
	  2086 series). The kernel will be slightly faster but will not work
	  on older machines.

config MARCH_Z9_109
	bool "IBM System z9"
	select HAVE_MARCH_Z9_109_FEATURES
	depends on $(cc-option,-march=z9-109)
	help
	  Select this to enable optimizations for IBM System z9 (2094 and
	  2096 series). The kernel will be slightly faster but will not work
	  on older machines.

config MARCH_Z10
	bool "IBM System z10"
	select HAVE_MARCH_Z10_FEATURES
	depends on $(cc-option,-march=z10)
	help
	  Select this to enable optimizations for IBM System z10 (2097 and
	  2098 series). The kernel will be slightly faster but will not work
	  on older machines.

config MARCH_Z196
	bool "IBM zEnterprise 114 and 196"
	select HAVE_MARCH_Z196_FEATURES
	depends on $(cc-option,-march=z196)
	help
	  Select this to enable optimizations for IBM zEnterprise 114 and 196
	  (2818 and 2817 series). The kernel will be slightly faster but will
	  not work on older machines.

config MARCH_ZEC12
	bool "IBM zBC12 and zEC12"
	select HAVE_MARCH_ZEC12_FEATURES
	depends on $(cc-option,-march=zEC12)
	help
	  Select this to enable optimizations for IBM zBC12 and zEC12 (2828 and
	  2827 series). The kernel will be slightly faster but will not work on
	  older machines.

config MARCH_Z13
	bool "IBM z13s and z13"
	select HAVE_MARCH_Z13_FEATURES
	depends on $(cc-option,-march=z13)
	help
	  Select this to enable optimizations for IBM z13s and z13 (2965 and
	  2964 series). The kernel will be slightly faster but will not work on
	  older machines.

config MARCH_Z14
	bool "IBM z14 ZR1 and z14"
	select HAVE_MARCH_Z14_FEATURES
	depends on $(cc-option,-march=z14)
	help
	  Select this to enable optimizations for IBM z14 ZR1 and z14 (3907
	  and 3906 series). The kernel will be slightly faster but will not
	  work on older machines.

config MARCH_Z15
	bool "IBM z15"
	select HAVE_MARCH_Z15_FEATURES
	depends on $(cc-option,-march=z15)
	help
	  Select this to enable optimizations for IBM z15 (8562
	  and 8561 series). The kernel will be slightly faster but will not
	  work on older machines.

endchoice

config MARCH_Z900_TUNE
	def_bool TUNE_Z900 || MARCH_Z900 && TUNE_DEFAULT

config MARCH_Z990_TUNE
	def_bool TUNE_Z990 || MARCH_Z990 && TUNE_DEFAULT

config MARCH_Z9_109_TUNE
	def_bool TUNE_Z9_109 || MARCH_Z9_109 && TUNE_DEFAULT

config MARCH_Z10_TUNE
	def_bool TUNE_Z10 || MARCH_Z10 && TUNE_DEFAULT

config MARCH_Z196_TUNE
	def_bool TUNE_Z196 || MARCH_Z196 && TUNE_DEFAULT

config MARCH_ZEC12_TUNE
	def_bool TUNE_ZEC12 || MARCH_ZEC12 && TUNE_DEFAULT

config MARCH_Z13_TUNE
	def_bool TUNE_Z13 || MARCH_Z13 && TUNE_DEFAULT

config MARCH_Z14_TUNE
	def_bool TUNE_Z14 || MARCH_Z14 && TUNE_DEFAULT

config MARCH_Z15_TUNE
	def_bool TUNE_Z15 || MARCH_Z15 && TUNE_DEFAULT

choice
	prompt "Tune code generation"
	default TUNE_DEFAULT
	help
	  Cause the compiler to tune (-mtune) the generated code for a machine.
	  This will make the code run faster on the selected machine but
	  somewhat slower on other machines.
	  This option only changes how the compiler emits instructions, not the
	  selection of instructions itself, so the resulting kernel will run on
	  all other machines.

config TUNE_DEFAULT
	bool "Default"
	help
	  Tune the generated code for the target processor for which the kernel
	  will be compiled.

config TUNE_Z900
	bool "IBM zSeries model z800 and z900"
	depends on $(cc-option,-mtune=z900)

config TUNE_Z990
	bool "IBM zSeries model z890 and z990"
	depends on $(cc-option,-mtune=z990)

config TUNE_Z9_109
	bool "IBM System z9"
	depends on $(cc-option,-mtune=z9-109)

config TUNE_Z10
	bool "IBM System z10"
	depends on $(cc-option,-mtune=z10)

config TUNE_Z196
	bool "IBM zEnterprise 114 and 196"
	depends on $(cc-option,-mtune=z196)

config TUNE_ZEC12
	bool "IBM zBC12 and zEC12"
	depends on $(cc-option,-mtune=zEC12)

config TUNE_Z13
	bool "IBM z13s and z13"
	depends on $(cc-option,-mtune=z13)

config TUNE_Z14
	bool "IBM z14 ZR1 and z14"
	depends on $(cc-option,-mtune=z14)

config TUNE_Z15
	bool "IBM z15"
	depends on $(cc-option,-mtune=z15)

endchoice

config 64BIT
	def_bool y

config COMPAT
	def_bool y
	prompt "Kernel support for 31 bit emulation"
	select COMPAT_BINFMT_ELF if BINFMT_ELF
	select ARCH_WANT_OLD_COMPAT_IPC
	select COMPAT_OLD_SIGACTION
	select HAVE_UID16
	depends on MULTIUSER
	help
	  Select this option if you want to enable your system kernel to
	  handle system-calls from ELF binaries for 31 bit ESA.  This option
	  (and some other stuff like libraries and such) is needed for
	  executing 31 bit applications.  It is safe to say "Y".

config SYSVIPC_COMPAT
	def_bool y if COMPAT && SYSVIPC

config SMP
	def_bool y

config NR_CPUS
	int "Maximum number of CPUs (2-512)"
	range 2 512
	default "64"
	help
	  This allows you to specify the maximum number of CPUs which this
	  kernel will support. The maximum supported value is 512 and the
	  minimum value which makes sense is 2.

	  This is purely to save memory - each supported CPU adds
	  approximately sixteen kilobytes to the kernel image.

config HOTPLUG_CPU
	def_bool y

# 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. <- They meant memory holes!
config NODES_SPAN_OTHER_NODES
	def_bool NUMA

config NUMA
	bool "NUMA support"
	depends on SCHED_TOPOLOGY
	default n
	help
	  Enable NUMA support

	  This option adds NUMA support to the kernel.

	  An operation mode can be selected by appending
	  numa=<method> to the kernel command line.

	  The default behaviour is identical to appending numa=plain to
	  the command line. This will create just one node with all
	  available memory and all CPUs in it.

config NODES_SHIFT
	int "Maximum NUMA nodes (as a power of 2)"
	range 1 10
	depends on NUMA
	default "4"
	help
	  Specify the maximum number of NUMA nodes available on the target
	  system. Increases memory reserved to accommodate various tables.

menu "Select NUMA modes"
	depends on NUMA

config NUMA_EMU
	bool "NUMA emulation"
	default y
	help
	  Numa emulation mode will split the available system memory into
	  equal chunks which then are distributed over the configured number
	  of nodes in a round-robin manner.

	  The number of fake nodes is limited by the number of available memory
	  chunks (i.e. memory size / fake size) and the number of supported
	  nodes in the kernel.

	  The CPUs are assigned to the nodes in a way that partially respects
	  the original machine topology (if supported by the machine).
	  Fair distribution of the CPUs is not guaranteed.

config EMU_SIZE
	hex "NUMA emulation memory chunk size"
	default 0x10000000
	range 0x400000 0x100000000
	depends on NUMA_EMU
	help
	  Select the default size by which the memory is chopped and then
	  assigned to emulated NUMA nodes.

	  This can be overridden by specifying

	  emu_size=<n>

	  on the kernel command line where also suffixes K, M, G, and T are
	  supported.

endmenu

config SCHED_SMT
	def_bool n

config SCHED_MC
	def_bool n

config SCHED_BOOK
	def_bool n

config SCHED_DRAWER
	def_bool n

config SCHED_TOPOLOGY
	def_bool y
	prompt "Topology scheduler support"
	select SCHED_SMT
	select SCHED_MC
	select SCHED_BOOK
	select SCHED_DRAWER
	help
	  Topology scheduler support improves the CPU scheduler's decision
	  making when dealing with machines that have multi-threading,
	  multiple cores or multiple books.

source "kernel/Kconfig.hz"

config KEXEC
	def_bool y
	select KEXEC_CORE

config KEXEC_FILE
	bool "kexec file based system call"
	select KEXEC_CORE
	select BUILD_BIN2C
	depends on CRYPTO
	depends on CRYPTO_SHA256
	depends on CRYPTO_SHA256_S390
	help
	  Enable the kexec file based system call. In contrast to the normal
	  kexec system call this system call takes file descriptors for the
	  kernel and initramfs as arguments.

config ARCH_HAS_KEXEC_PURGATORY
	def_bool y
	depends on KEXEC_FILE

config KEXEC_SIG
	bool "Verify kernel signature during kexec_file_load() syscall"
	depends on KEXEC_FILE && MODULE_SIG_FORMAT
	help
	  This option makes kernel signature verification mandatory for
	  the kexec_file_load() syscall.

	  In addition to that option, you need to enable signature
	  verification for the corresponding kernel image type being
	  loaded in order for this to work.

config ARCH_RANDOM
	def_bool y
	prompt "s390 architectural random number generation API"
	help
	  Enable the s390 architectural random number generation API
	  to provide random data for all consumers within the Linux
	  kernel.

	  When enabled the arch_random_* functions declared in linux/random.h
	  are implemented. The implementation is based on the s390 CPACF
	  instruction subfunction TRNG which provides a real true random
	  number generator.

	  If unsure, say Y.

config KERNEL_NOBP
	def_bool n
	prompt "Enable modified branch prediction for the kernel by default"
	help
	  If this option is selected the kernel will switch to a modified
	  branch prediction mode if the firmware interface is available.
	  The modified branch prediction mode improves the behaviour in
	  regard to speculative execution.

	  With the option enabled the kernel parameter "nobp=0" or "nospec"
	  can be used to run the kernel in the normal branch prediction mode.

	  With the option disabled the modified branch prediction mode is
	  enabled with the "nobp=1" kernel parameter.

	  If unsure, say N.

config EXPOLINE
	def_bool n
	prompt "Avoid speculative indirect branches in the kernel"
	help
	  Compile the kernel with the expoline compiler options to guard
	  against kernel-to-user data leaks by avoiding speculative indirect
	  branches.
	  Requires a compiler with -mindirect-branch=thunk support for full
	  protection. The kernel may run slower.

	  If unsure, say N.

choice
	prompt "Expoline default"
	depends on EXPOLINE
	default EXPOLINE_FULL

config EXPOLINE_OFF
	bool "spectre_v2=off"

config EXPOLINE_AUTO
	bool "spectre_v2=auto"

config EXPOLINE_FULL
	bool "spectre_v2=on"

endchoice

config RELOCATABLE
	bool "Build a relocatable kernel"
	select MODULE_REL_CRCS if MODVERSIONS
	default y
	help
	  This builds a kernel image that retains relocation information
	  so it can be loaded at an arbitrary address.
	  The kernel is linked as a position-independent executable (PIE)
	  and contains dynamic relocations which are processed early in the
	  bootup process.
	  The relocations make the kernel image about 15% larger (compressed
	  10%), but are discarded at runtime.

config RANDOMIZE_BASE
	bool "Randomize the address of the kernel image (KASLR)"
	depends on RELOCATABLE
	default y
	help
	  In support of Kernel Address Space Layout Randomization (KASLR),
	  this randomizes the address at which the kernel image is loaded,
	  as a security feature that deters exploit attempts relying on
	  knowledge of the location of kernel internals.

endmenu

menu "Memory setup"

config ARCH_SPARSEMEM_ENABLE
	def_bool y
	select SPARSEMEM_VMEMMAP_ENABLE
	select SPARSEMEM_VMEMMAP

config ARCH_SPARSEMEM_DEFAULT
	def_bool y

config ARCH_ENABLE_MEMORY_HOTPLUG
	def_bool y if SPARSEMEM

config ARCH_ENABLE_MEMORY_HOTREMOVE
	def_bool y

config ARCH_ENABLE_SPLIT_PMD_PTLOCK
	def_bool y

config FORCE_MAX_ZONEORDER
	int
	default "9"

config MAX_PHYSMEM_BITS
	int "Maximum size of supported physical memory in bits (42-53)"
	range 42 53
	default "46"
	help
	  This option specifies the maximum supported size of physical memory
	  in bits. Supported is any size between 2^42 (4TB) and 2^53 (8PB).
	  Increasing the number of bits also increases the kernel image size.
	  By default 46 bits (64TB) are supported.

config PACK_STACK
	def_bool y
	prompt "Pack kernel stack"
	help
	  This option enables the compiler option -mkernel-backchain if it
	  is available. If the option is available the compiler supports
	  the new stack layout which dramatically reduces the minimum stack
	  frame size. With an old compiler a non-leaf function needs a
	  minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
	  -mkernel-backchain the minimum size drops to 16 byte on 31 bit
	  and 24 byte on 64 bit.

	  Say Y if you are unsure.

config CHECK_STACK
	def_bool y
	depends on !VMAP_STACK
	prompt "Detect kernel stack overflow"
	help
	  This option enables the compiler option -mstack-guard and
	  -mstack-size if they are available. If the compiler supports them
	  it will emit additional code to each function prolog to trigger
	  an illegal operation if the kernel stack is about to overflow.

	  Say N if you are unsure.

config STACK_GUARD
	int "Size of the guard area (128-1024)"
	range 128 1024
	depends on CHECK_STACK
	default "256"
	help
	  This allows you to specify the size of the guard area at the lower
	  end of the kernel stack. If the kernel stack points into the guard
	  area on function entry an illegal operation is triggered. The size
	  needs to be a power of 2. Please keep in mind that the size of an
	  interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
	  The minimum size for the stack guard should be 256 for 31 bit and
	  512 for 64 bit.

config WARN_DYNAMIC_STACK
	def_bool n
	prompt "Emit compiler warnings for function with dynamic stack usage"
	help
	  This option enables the compiler option -mwarn-dynamicstack. If the
	  compiler supports this options generates warnings for functions
	  that dynamically allocate stack space using alloca.

	  Say N if you are unsure.

endmenu

menu "I/O subsystem"

config QDIO
	def_tristate y
	prompt "QDIO support"
	---help---
	  This driver provides the Queued Direct I/O base support for
	  IBM System z.

	  To compile this driver as a module, choose M here: the
	  module will be called qdio.

	  If unsure, say Y.

if PCI

config PCI_NR_FUNCTIONS
	int "Maximum number of PCI functions (1-4096)"
	range 1 4096
	default "128"
	help
	  This allows you to specify the maximum number of PCI functions which
	  this kernel will support.

endif # PCI

config HAS_IOMEM
	def_bool PCI

config CHSC_SCH
	def_tristate m
	prompt "Support for CHSC subchannels"
	help
	  This driver allows usage of CHSC subchannels. A CHSC subchannel
	  is usually present on LPAR only.
	  The driver creates a device /dev/chsc, which may be used to
	  obtain I/O configuration information about the machine and
	  to issue asynchronous chsc commands (DANGEROUS).
	  You will usually only want to use this interface on a special
	  LPAR designated for system management.

	  To compile this driver as a module, choose M here: the
	  module will be called chsc_sch.

	  If unsure, say N.

config SCM_BUS
	def_bool y
	prompt "SCM bus driver"
	help
	  Bus driver for Storage Class Memory.

config EADM_SCH
	def_tristate m
	prompt "Support for EADM subchannels"
	depends on SCM_BUS
	help
	  This driver allows usage of EADM subchannels. EADM subchannels act
	  as a communication vehicle for SCM increments.

	  To compile this driver as a module, choose M here: the
	  module will be called eadm_sch.

config VFIO_CCW
	def_tristate n
	prompt "Support for VFIO-CCW subchannels"
	depends on S390_CCW_IOMMU && VFIO_MDEV
	help
	  This driver allows usage of I/O subchannels via VFIO-CCW.

	  To compile this driver as a module, choose M here: the
	  module will be called vfio_ccw.

config VFIO_AP
	def_tristate n
	prompt "VFIO support for AP devices"
	depends on S390_AP_IOMMU && VFIO_MDEV_DEVICE && KVM
	help
		This driver grants access to Adjunct Processor (AP) devices
		via the VFIO mediated device interface.

		To compile this driver as a module, choose M here: the module
		will be called vfio_ap.

endmenu

menu "Dump support"

config CRASH_DUMP
	bool "kernel crash dumps"
	select KEXEC
	help
	  Generate crash dump after being started by kexec.
	  Crash dump kernels are loaded in the main kernel with kexec-tools
	  into a specially reserved region and then later executed after
	  a crash by kdump/kexec.
	  Refer to <file:Documentation/s390/zfcpdump.rst> for more details on this.
	  This option also enables s390 zfcpdump.
	  See also <file:Documentation/s390/zfcpdump.rst>

endmenu

config SECCOMP
	def_bool y
	prompt "Enable seccomp to safely compute untrusted bytecode"
	depends on PROC_FS
	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.

menu "Power Management"

config ARCH_HIBERNATION_POSSIBLE
	def_bool y

source "kernel/power/Kconfig"

endmenu

config CCW
	def_bool y

config HAVE_PNETID
	tristate
	default (SMC || CCWGROUP)

menu "Virtualization"

config PROTECTED_VIRTUALIZATION_GUEST
	def_bool n
	prompt "Protected virtualization guest support"
	help
	  Select this option, if you want to be able to run this
	  kernel as a protected virtualization KVM guest.
	  Protected virtualization capable machines have a mini hypervisor
	  located at machine level (an ultravisor). With help of the
	  Ultravisor, KVM will be able to run "protected" VMs, special
	  VMs whose memory and management data are unavailable to KVM.

config PFAULT
	def_bool y
	prompt "Pseudo page fault support"
	help
	  Select this option, if you want to use PFAULT pseudo page fault
	  handling under VM. If running native or in LPAR, this option
	  has no effect. If your VM does not support PFAULT, PAGEEX
	  pseudo page fault handling will be used.
	  Note that VM 4.2 supports PFAULT but has a bug in its
	  implementation that causes some problems.
	  Everybody who wants to run Linux under VM != VM4.2 should select
	  this option.

config CMM
	def_tristate n
	prompt "Cooperative memory management"
	help
	  Select this option, if you want to enable the kernel interface
	  to reduce the memory size of the system. This is accomplished
	  by allocating pages of memory and put them "on hold". This only
	  makes sense for a system running under VM where the unused pages
	  will be reused by VM for other guest systems. The interface
	  allows an external monitor to balance memory of many systems.
	  Everybody who wants to run Linux under VM should select this
	  option.

config CMM_IUCV
	def_bool y
	prompt "IUCV special message interface to cooperative memory management"
	depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
	help
	  Select this option to enable the special message interface to
	  the cooperative memory management.

config APPLDATA_BASE
	def_bool n
	prompt "Linux - VM Monitor Stream, base infrastructure"
	depends on PROC_FS
	help
	  This provides a kernel interface for creating and updating z/VM APPLDATA
	  monitor records. The monitor records are updated at certain time
	  intervals, once the timer is started.
	  Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
	  i.e. enables or disables monitoring on the Linux side.
	  A custom interval value (in seconds) can be written to
	  /proc/appldata/interval.

	  Defaults are 60 seconds interval and timer off.
	  The /proc entries can also be read from, showing the current settings.

config APPLDATA_MEM
	def_tristate m
	prompt "Monitor memory management statistics"
	depends on APPLDATA_BASE && VM_EVENT_COUNTERS
	help
	  This provides memory management related data to the Linux - VM Monitor
	  Stream, like paging/swapping rate, memory utilisation, etc.
	  Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
	  APPLDATA monitor record, i.e. enables or disables monitoring this record
	  on the z/VM side.

	  Default is disabled.
	  The /proc entry can also be read from, showing the current settings.

	  This can also be compiled as a module, which will be called
	  appldata_mem.o.

config APPLDATA_OS
	def_tristate m
	prompt "Monitor OS statistics"
	depends on APPLDATA_BASE
	help
	  This provides OS related data to the Linux - VM Monitor Stream, like
	  CPU utilisation, etc.
	  Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
	  APPLDATA monitor record, i.e. enables or disables monitoring this record
	  on the z/VM side.

	  Default is disabled.
	  This can also be compiled as a module, which will be called
	  appldata_os.o.

config APPLDATA_NET_SUM
	def_tristate m
	prompt "Monitor overall network statistics"
	depends on APPLDATA_BASE && NET
	help
	  This provides network related data to the Linux - VM Monitor Stream,
	  currently there is only a total sum of network I/O statistics, no
	  per-interface data.
	  Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
	  APPLDATA monitor record, i.e. enables or disables monitoring this record
	  on the z/VM side.

	  Default is disabled.
	  This can also be compiled as a module, which will be called
	  appldata_net_sum.o.

config S390_HYPFS_FS
	def_bool y
	prompt "s390 hypervisor file system support"
	select SYS_HYPERVISOR
	help
	  This is a virtual file system intended to provide accounting
	  information in an s390 hypervisor environment.

source "arch/s390/kvm/Kconfig"

config S390_GUEST
	def_bool y
	prompt "s390 support for virtio devices"
	select TTY
	select VIRTUALIZATION
	select VIRTIO
	select VIRTIO_CONSOLE
	help
	  Enabling this option adds support for virtio based paravirtual device
	  drivers on s390.

	  Select this option if you want to run the kernel as a guest under
	  the KVM hypervisor.

endmenu

menu "Selftests"

config S390_UNWIND_SELFTEST
	def_tristate n
	prompt "Test unwind functions"
	help
	  This option enables s390 specific stack unwinder testing kernel
	  module. This option is not useful for distributions or general
	  kernels, but only for kernel developers working on architecture code.

	  Say N if you are unsure.

endmenu