# 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_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 DMA_OPS if PCI 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 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 for more details on this. This option also enables s390 zfcpdump. See also 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. 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 y if EXPOLINE depends on EXPOLINE depends on CC_IS_GCC && GCC_VERSION >= 110200 depends on $(success,$(srctree)/arch/s390/tools/gcc-thunk-extern.sh $(CC)) prompt "Generate expolines as extern functions." help This option is required for some tooling like kpatch. The kernel is compiled with -mindirect-branch=thunk-extern and requires a newer compiler. 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 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 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