xref: /linux/arch/s390/Kconfig (revision 42b16d3ac371a2fac9b6f08fd75f23f34ba3955a)

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

config GENERIC_HWEIGHT
	def_bool !HAVE_MARCH_Z196_FEATURES

config GENERIC_BUG
	def_bool y if BUG

config GENERIC_BUG_RELATIVE_POINTERS
	def_bool y

config GENERIC_LOCKBREAK
	def_bool y if PREEMPTION

config PGSTE
	def_bool y if KVM

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 0x1C000000000000

config S390
	def_bool y
	#
	# Note: keep this list sorted alphabetically
	#
	imply IMA_SECURE_AND_OR_TRUSTED_BOOT
	select ALTERNATE_USER_ADDRESS_SPACE
	select ARCH_32BIT_USTAT_F_TINODE
	select ARCH_BINFMT_ELF_STATE
	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
	select ARCH_ENABLE_MEMORY_HOTPLUG if SPARSEMEM
	select ARCH_ENABLE_MEMORY_HOTREMOVE
	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
	select ARCH_HAS_CURRENT_STACK_POINTER
	select ARCH_HAS_DEBUG_VIRTUAL
	select ARCH_HAS_DEBUG_VM_PGTABLE
	select ARCH_HAS_DEBUG_WX
	select ARCH_HAS_DEVMEM_IS_ALLOWED
	select ARCH_HAS_DMA_OPS if PCI
	select ARCH_HAS_ELF_RANDOMIZE
	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
	select ARCH_HAS_FORTIFY_SOURCE
	select ARCH_HAS_GCOV_PROFILE_ALL
	select ARCH_HAS_GIGANTIC_PAGE
	select ARCH_HAS_KCOV
	select ARCH_HAS_MEMBARRIER_SYNC_CORE
	select ARCH_HAS_MEM_ENCRYPT
	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
	select ARCH_HAS_PTE_SPECIAL
	select ARCH_HAS_SCALED_CPUTIME
	select ARCH_HAS_SET_DIRECT_MAP
	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
	select ARCH_HAS_VDSO_DATA
	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_MHP_MEMMAP_ON_MEMORY_ENABLE
	select ARCH_STACKWALK
	select ARCH_SUPPORTS_ATOMIC_RMW
	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
	select ARCH_SUPPORTS_HUGETLBFS
	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && CC_IS_CLANG
	select ARCH_SUPPORTS_NUMA_BALANCING
	select ARCH_SUPPORTS_PER_VMA_LOCK
	select ARCH_USE_BUILTIN_BSWAP
	select ARCH_USE_CMPXCHG_LOCKREF
	select ARCH_USE_SYM_ANNOTATIONS
	select ARCH_WANTS_NO_INSTR
	select ARCH_WANT_DEFAULT_BPF_JIT
	select ARCH_WANT_IPC_PARSE_VERSION
	select ARCH_WANT_KERNEL_PMD_MKWRITE
	select ARCH_WANT_LD_ORPHAN_WARN
	select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP
	select BUILDTIME_TABLE_SORT
	select CLONE_BACKWARDS2
	select DCACHE_WORD_ACCESS if !KMSAN
	select DYNAMIC_FTRACE if FUNCTION_TRACER
	select FUNCTION_ALIGNMENT_8B if CC_IS_GCC
	select FUNCTION_ALIGNMENT_16B if !CC_IS_GCC
	select GENERIC_ALLOCATOR
	select GENERIC_CPU_DEVICES
	select GENERIC_CPU_AUTOPROBE
	select GENERIC_CPU_VULNERABILITIES
	select GENERIC_ENTRY
	select GENERIC_GETTIMEOFDAY
	select GENERIC_PTDUMP
	select GENERIC_SMP_IDLE_THREAD
	select GENERIC_TIME_VSYSCALL
	select GENERIC_VDSO_TIME_NS
	select GENERIC_IOREMAP if PCI
	select HAVE_ALIGNED_STRUCT_PAGE
	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 HAVE_ARCH_KCSAN
	select HAVE_ARCH_KMSAN
	select HAVE_ARCH_KFENCE
	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
	select HAVE_ARCH_SECCOMP_FILTER
	select HAVE_ARCH_SOFT_DIRTY
	select HAVE_ARCH_STACKLEAK
	select HAVE_ARCH_TRACEHOOK
	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
	select HAVE_ARCH_VMAP_STACK
	select HAVE_ASM_MODVERSIONS
	select HAVE_CMPXCHG_DOUBLE
	select HAVE_CMPXCHG_LOCAL
	select HAVE_DEBUG_KMEMLEAK
	select HAVE_DMA_CONTIGUOUS
	select HAVE_DYNAMIC_FTRACE
	select HAVE_DYNAMIC_FTRACE_WITH_ARGS
	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
	select HAVE_DYNAMIC_FTRACE_WITH_REGS
	select HAVE_EBPF_JIT if HAVE_MARCH_Z196_FEATURES
	select HAVE_EFFICIENT_UNALIGNED_ACCESS
	select HAVE_GUP_FAST
	select HAVE_FENTRY
	select HAVE_FTRACE_MCOUNT_RECORD
	select HAVE_FUNCTION_ARG_ACCESS_API
	select HAVE_FUNCTION_ERROR_INJECTION
	select HAVE_FUNCTION_GRAPH_RETVAL
	select HAVE_FUNCTION_GRAPH_TRACER
	select HAVE_FUNCTION_TRACER
	select HAVE_GCC_PLUGINS
	select HAVE_GENERIC_VDSO
	select HAVE_IOREMAP_PROT if PCI
	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_KERNEL_ZSTD
	select HAVE_KPROBES
	select HAVE_KPROBES_ON_FTRACE
	select HAVE_KRETPROBES
	select HAVE_LIVEPATCH
	select HAVE_MEMBLOCK_PHYS_MAP
	select HAVE_MOD_ARCH_SPECIFIC
	select HAVE_NMI
	select HAVE_NOP_MCOUNT
	select HAVE_PAGE_SIZE_4KB
	select HAVE_PCI
	select HAVE_PERF_EVENTS
	select HAVE_PERF_REGS
	select HAVE_PERF_USER_STACK_DUMP
	select HAVE_REGS_AND_STACK_ACCESS_API
	select HAVE_RELIABLE_STACKTRACE
	select HAVE_RETHOOK
	select HAVE_RSEQ
	select HAVE_SAMPLE_FTRACE_DIRECT
	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI
	select HAVE_SETUP_PER_CPU_AREA
	select HAVE_SOFTIRQ_ON_OWN_STACK
	select HAVE_SYSCALL_TRACEPOINTS
	select HAVE_VIRT_CPU_ACCOUNTING
	select HAVE_VIRT_CPU_ACCOUNTING_IDLE
	select IOMMU_HELPER		if PCI
	select IOMMU_SUPPORT		if PCI
	select MMU_GATHER_MERGE_VMAS
	select MMU_GATHER_NO_GATHER
	select MMU_GATHER_RCU_TABLE_FREE
	select MODULES_USE_ELF_RELA
	select NEED_DMA_MAP_STATE	if PCI
	select NEED_PER_CPU_EMBED_FIRST_CHUNK
	select NEED_SG_DMA_LENGTH	if PCI
	select OLD_SIGACTION
	select OLD_SIGSUSPEND3
	select PCI_DOMAINS		if PCI
	select PCI_MSI			if PCI
	select PCI_MSI_ARCH_FALLBACKS	if PCI_MSI
	select SPARSE_IRQ
	select SWIOTLB
	select SYSCTL_EXCEPTION_TRACE
	select THREAD_INFO_IN_TASK
	select TRACE_IRQFLAGS_SUPPORT
	select TTY
	select USER_STACKTRACE_SUPPORT
	select VDSO_GETRANDOM
	select VIRT_CPU_ACCOUNTING
	select ZONE_DMA
	# Note: keep the above list sorted alphabetically

config SCHED_OMIT_FRAME_POINTER
	def_bool y

config PGTABLE_LEVELS
	int
	default 5

source "kernel/livepatch/Kconfig"

config ARCH_SUPPORTS_KEXEC
	def_bool y

config ARCH_SUPPORTS_KEXEC_FILE
	def_bool y

config ARCH_SUPPORTS_KEXEC_SIG
	def_bool MODULE_SIG_FORMAT

config ARCH_SUPPORTS_KEXEC_PURGATORY
	def_bool y

config ARCH_SUPPORTS_CRASH_DUMP
	def_bool y
	help
	  Refer to <file:Documentation/arch/s390/zfcpdump.rst> for more details on this.
	  This option also enables s390 zfcpdump.
	  See also <file:Documentation/arch/s390/zfcpdump.rst>

menu "Processor type and features"

config HAVE_MARCH_Z10_FEATURES
	def_bool n

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

config HAVE_MARCH_Z16_FEATURES
	def_bool n
	select HAVE_MARCH_Z15_FEATURES

choice
	prompt "Processor type"
	default MARCH_Z196

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). This is the oldest machine generation currently supported.

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.

config MARCH_Z16
	bool "IBM z16"
	select HAVE_MARCH_Z16_FEATURES
	depends on $(cc-option,-march=z16)
	help
	  Select this to enable optimizations for IBM z16 (3931 and
	  3932 series).

endchoice

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

config MARCH_Z16_TUNE
	def_bool TUNE_Z16 || MARCH_Z16 && 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_Z10
	bool "IBM System 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)

config TUNE_Z16
	bool "IBM z16"
	depends on $(cc-option,-mtune=z16)

endchoice

config 64BIT
	def_bool y

config COMMAND_LINE_SIZE
	int "Maximum size of kernel command line"
	default 4096
	range 896 1048576
	help
	  This allows you to specify the maximum length of the kernel command
	  line.

config COMPAT
	def_bool n
	prompt "Kernel support for 31 bit emulation"
	select ARCH_WANT_OLD_COMPAT_IPC
	select COMPAT_OLD_SIGACTION
	select HAVE_UID16
	depends on MULTIUSER
	depends on !CC_IS_CLANG && !LD_IS_LLD
	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.

	  If unsure say N.

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

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

	  This option adds NUMA support to the kernel.

config NODES_SHIFT
	int
	depends on NUMA
	default "1"

config SCHED_SMT
	def_bool n

config SCHED_MC
	def_bool n

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

config SCHED_TOPOLOGY_VERTICAL
	def_bool y
	bool "Use vertical CPU polarization by default"
	depends on SCHED_TOPOLOGY
	help
	  Use vertical CPU polarization by default if available.
	  The default CPU polarization is horizontal.

config HIPERDISPATCH_ON
	def_bool y
	bool "Use hiperdispatch on vertical polarization by default"
	depends on SCHED_TOPOLOGY
	depends on PROC_SYSCTL
	help
	  Hiperdispatch aims to improve the CPU scheduler's decision
	  making when using vertical polarization by adjusting CPU
	  capacities dynamically. Set this option to use hiperdispatch
	  on vertical polarization by default. This can be overwritten
	  by sysctl's s390.hiperdispatch attribute later on.

source "kernel/Kconfig.hz"

config CERT_STORE
	bool "Get user certificates via DIAG320"
	depends on KEYS
	select CRYPTO_LIB_SHA256
	help
	  Enable this option if you want to access user-provided secure boot
	  certificates via DIAG 0x320.

	  These certificates will be made available via the keyring named
	  'cert_store'.

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
	depends on $(cc-option,-mindirect-branch=thunk)
	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.

config EXPOLINE_EXTERN
	def_bool EXPOLINE && CC_IS_GCC && GCC_VERSION >= 110200 && \
		 $(success,$(srctree)/arch/s390/tools/gcc-thunk-extern.sh $(CC))
	help
	  Generate expolines as external functions if the compiler supports it.
	  This option is required for some tooling like kpatch, if expolines
	  are enabled. The kernel is compiled with
	  -mindirect-branch=thunk-extern, which requires a newer compiler.

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
	def_bool y
	help
	  This builds a kernel image that retains relocation information
	  so it can be loaded at an arbitrary address.
	  The relocations make the kernel image about 15% larger (compressed
	  10%), but are discarded at runtime.
	  Note: this option exists only for documentation purposes, please do
	  not remove it.

config RANDOMIZE_BASE
	bool "Randomize the address of the kernel image (KASLR)"
	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.

config RANDOMIZE_IDENTITY_BASE
	bool "Randomize the address of the identity mapping base"
	depends on RANDOMIZE_BASE
	default DEBUG_VM
	help
	  The identity mapping base address is pinned to zero by default.
	  Allow randomization of that base to expose otherwise missed
	  notion of physical and virtual addresses of data structures.
	  That does not have any impact on the base address at which the
	  kernel image is loaded.

	  If unsure, say N

config KERNEL_IMAGE_BASE
	hex "Kernel image base address"
	range 0x100000 0x1FFFFFE0000000 if !KASAN
	range 0x100000 0x1BFFFFE0000000 if KASAN
	default 0x3FFE0000000 if !KASAN
	default 0x7FFFE0000000 if KASAN
	help
	  This is the address at which the kernel image is loaded in case
	  Kernel Address Space Layout Randomization (KASLR) is disabled.

	  In case the Protected virtualization guest support is enabled the
	  Ultravisor imposes a virtual address limit. If the value of this
	  option leads to the kernel image exceeding the Ultravisor limit,
	  this option is ignored and the image is loaded below the limit.

	  If the value of this option leads to the kernel image overlapping
	  the virtual memory where other data structures are located, this
	  option is ignored and the image is loaded above the structures.

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 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 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.

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 "512"
	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 AP
	def_tristate y
	prompt "Support for Adjunct Processors (ap)"
	help
	  This driver allows usage to Adjunct Processor (AP) devices via
	  the ap bus, cards and queues. Supported Adjunct Processors are
	  the CryptoExpress Cards (CEX).

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

	  If unsure, say Y (default).

config AP_DEBUG
	def_bool n
	prompt "Enable debug features for Adjunct Processor (ap) devices"
	depends on AP
	help
	  Say 'Y' here to enable some additional debug features for Adjunct
	  Processor (ap) devices.

	  There will be some more sysfs attributes displayed for ap queues.

	  Do not enable on production level kernel build.

	  If unsure, say N.

config VFIO_CCW
	def_tristate n
	prompt "Support for VFIO-CCW subchannels"
	depends on VFIO
	select 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 KVM
	depends on VFIO
	depends on AP
	select VFIO_MDEV
	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

config CCW
	def_bool y

config HAVE_PNETID
	tristate
	default (SMC || CCWGROUP)

menu "Virtualization"

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_SYSCTL
	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
	def_bool y
	prompt "s390 hypervisor information"
	help
	  This provides several binary files at (debugfs)/s390_hypfs/ to
	  provide accounting information in an s390 hypervisor environment.

config S390_HYPFS_FS
	def_bool n
	prompt "s390 hypervisor file system support"
	select SYS_HYPERVISOR
	depends on S390_HYPFS
	help
	  This is a virtual file system intended to provide accounting
	  information in an s390 hypervisor environment. This file system
	  is deprecated and should not be used.

	  Say N if you are unsure.

source "arch/s390/kvm/Kconfig"

config S390_GUEST
	def_bool y
	prompt "s390 support for virtio devices"
	select TTY
	select VIRTUALIZATION
	select VIRTIO
	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

config S390_MODULES_SANITY_TEST_HELPERS
	def_bool n

menu "Selftests"

config S390_UNWIND_SELFTEST
	def_tristate n
	depends on KUNIT
	default KUNIT_ALL_TESTS
	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.

config S390_KPROBES_SANITY_TEST
	def_tristate n
	prompt "Enable s390 specific kprobes tests"
	depends on KPROBES
	depends on KUNIT
	help
	  This option enables an s390 specific kprobes test 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.

config S390_MODULES_SANITY_TEST
	def_tristate n
	depends on KUNIT
	default KUNIT_ALL_TESTS
	prompt "Enable s390 specific modules tests"
	select S390_MODULES_SANITY_TEST_HELPERS
	help
	  This option enables an s390 specific modules test. 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