arch/s390/Kconfig

   1 # SPDX-License-Identifier: GPL-2.0
   2 config MMU
   3         def_bool y
   4
   5 config ZONE_DMA
   6         def_bool y
   7
   8 config CPU_BIG_ENDIAN
   9         def_bool y
  10
  11 config LOCKDEP_SUPPORT
  12         def_bool y
  13
  14 config STACKTRACE_SUPPORT
  15         def_bool y
  16
  17 config RWSEM_GENERIC_SPINLOCK
  18         bool
  19
  20 config RWSEM_XCHGADD_ALGORITHM
  21         def_bool y
  22
  23 config ARCH_HAS_ILOG2_U32
  24         def_bool n
  25
  26 config ARCH_HAS_ILOG2_U64
  27         def_bool n
  28
  29 config GENERIC_HWEIGHT
  30         def_bool y
  31
  32 config GENERIC_BUG
  33         def_bool y if BUG
  34
  35 config GENERIC_BUG_RELATIVE_POINTERS
  36         def_bool y
  37
  38 config ARCH_DMA_ADDR_T_64BIT
  39         def_bool y
  40
  41 config GENERIC_LOCKBREAK
  42         def_bool y if SMP && PREEMPT
  43
  44 config PGSTE
  45         def_bool y if KVM
  46
  47 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
  48         def_bool y
  49
  50 config KEXEC
  51         def_bool y
  52         select KEXEC_CORE
  53
  54 config AUDIT_ARCH
  55         def_bool y
  56
  57 config NO_IOPORT_MAP
  58         def_bool y
  59
  60 config PCI_QUIRKS
  61         def_bool n
  62
  63 config ARCH_SUPPORTS_UPROBES
  64         def_bool y
  65
  66 config S390
  67         def_bool y
  68         select ARCH_BINFMT_ELF_STATE
  69         select ARCH_HAS_DEVMEM_IS_ALLOWED
  70         select ARCH_HAS_ELF_RANDOMIZE
  71         select ARCH_HAS_FORTIFY_SOURCE
  72         select ARCH_HAS_GCOV_PROFILE_ALL
  73         select ARCH_HAS_GIGANTIC_PAGE if (MEMORY_ISOLATION && COMPACTION) || CMA
  74         select ARCH_HAS_KCOV
  75         select ARCH_HAS_SET_MEMORY
  76         select ARCH_HAS_SG_CHAIN
  77         select ARCH_HAS_STRICT_KERNEL_RWX
  78         select ARCH_HAS_STRICT_MODULE_RWX
  79         select ARCH_HAS_UBSAN_SANITIZE_ALL
  80         select ARCH_HAVE_NMI_SAFE_CMPXCHG
  81         select ARCH_INLINE_READ_LOCK
  82         select ARCH_INLINE_READ_LOCK_BH
  83         select ARCH_INLINE_READ_LOCK_IRQ
  84         select ARCH_INLINE_READ_LOCK_IRQSAVE
  85         select ARCH_INLINE_READ_TRYLOCK
  86         select ARCH_INLINE_READ_UNLOCK
  87         select ARCH_INLINE_READ_UNLOCK_BH
  88         select ARCH_INLINE_READ_UNLOCK_IRQ
  89         select ARCH_INLINE_READ_UNLOCK_IRQRESTORE
  90         select ARCH_INLINE_SPIN_LOCK
  91         select ARCH_INLINE_SPIN_LOCK_BH
  92         select ARCH_INLINE_SPIN_LOCK_IRQ
  93         select ARCH_INLINE_SPIN_LOCK_IRQSAVE
  94         select ARCH_INLINE_SPIN_TRYLOCK
  95         select ARCH_INLINE_SPIN_TRYLOCK_BH
  96         select ARCH_INLINE_SPIN_UNLOCK
  97         select ARCH_INLINE_SPIN_UNLOCK_BH
  98         select ARCH_INLINE_SPIN_UNLOCK_IRQ
  99         select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE
 100         select ARCH_INLINE_WRITE_LOCK
 101         select ARCH_INLINE_WRITE_LOCK_BH
 102         select ARCH_INLINE_WRITE_LOCK_IRQ
 103         select ARCH_INLINE_WRITE_LOCK_IRQSAVE
 104         select ARCH_INLINE_WRITE_TRYLOCK
 105         select ARCH_INLINE_WRITE_UNLOCK
 106         select ARCH_INLINE_WRITE_UNLOCK_BH
 107         select ARCH_INLINE_WRITE_UNLOCK_IRQ
 108         select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
 109         select ARCH_SAVE_PAGE_KEYS if HIBERNATION
 110         select ARCH_SUPPORTS_ATOMIC_RMW
 111         select ARCH_SUPPORTS_NUMA_BALANCING
 112         select ARCH_USE_BUILTIN_BSWAP
 113         select ARCH_USE_CMPXCHG_LOCKREF
 114         select ARCH_WANTS_DYNAMIC_TASK_STRUCT
 115         select ARCH_WANTS_UBSAN_NO_NULL
 116         select ARCH_WANT_IPC_PARSE_VERSION
 117         select BUILDTIME_EXTABLE_SORT
 118         select CLONE_BACKWARDS2
 119         select DYNAMIC_FTRACE if FUNCTION_TRACER
 120         select GENERIC_CLOCKEVENTS
 121         select GENERIC_CPU_AUTOPROBE
 122         select GENERIC_CPU_DEVICES if !SMP
 123         select GENERIC_CPU_VULNERABILITIES
 124         select GENERIC_FIND_FIRST_BIT
 125         select GENERIC_SMP_IDLE_THREAD
 126         select GENERIC_TIME_VSYSCALL
 127         select HAVE_ALIGNED_STRUCT_PAGE if SLUB
 128         select HAVE_ARCH_AUDITSYSCALL
 129         select HAVE_ARCH_JUMP_LABEL
 130         select CPU_NO_EFFICIENT_FFS if !HAVE_MARCH_Z9_109_FEATURES
 131         select HAVE_ARCH_SECCOMP_FILTER
 132         select HAVE_ARCH_SOFT_DIRTY
 133         select HAVE_ARCH_TRACEHOOK
 134         select HAVE_ARCH_TRANSPARENT_HUGEPAGE
 135         select HAVE_EBPF_JIT if PACK_STACK && HAVE_MARCH_Z196_FEATURES
 136         select HAVE_CMPXCHG_DOUBLE
 137         select HAVE_CMPXCHG_LOCAL
 138         select HAVE_COPY_THREAD_TLS
 139         select HAVE_DEBUG_KMEMLEAK
 140         select HAVE_DMA_API_DEBUG
 141         select HAVE_DMA_CONTIGUOUS
 142         select DMA_DIRECT_OPS
 143         select HAVE_DYNAMIC_FTRACE
 144         select HAVE_DYNAMIC_FTRACE_WITH_REGS
 145         select HAVE_EFFICIENT_UNALIGNED_ACCESS
 146         select HAVE_FTRACE_MCOUNT_RECORD
 147         select HAVE_FUNCTION_GRAPH_TRACER
 148         select HAVE_FUNCTION_TRACER
 149         select HAVE_FUTEX_CMPXCHG if FUTEX
 150         select HAVE_GCC_PLUGINS
 151         select HAVE_KERNEL_BZIP2
 152         select HAVE_KERNEL_GZIP
 153         select HAVE_KERNEL_LZ4
 154         select HAVE_KERNEL_LZMA
 155         select HAVE_KERNEL_LZO
 156         select HAVE_KERNEL_XZ
 157         select HAVE_KPROBES
 158         select HAVE_KRETPROBES
 159         select HAVE_KVM
 160         select HAVE_LIVEPATCH
 161         select HAVE_PERF_REGS
 162         select HAVE_PERF_USER_STACK_DUMP
 163         select HAVE_MEMBLOCK
 164         select HAVE_MEMBLOCK_NODE_MAP
 165         select HAVE_MEMBLOCK_PHYS_MAP
 166         select HAVE_MOD_ARCH_SPECIFIC
 167         select HAVE_OPROFILE
 168         select HAVE_PERF_EVENTS
 169         select HAVE_REGS_AND_STACK_ACCESS_API
 170         select HAVE_SYSCALL_TRACEPOINTS
 171         select HAVE_VIRT_CPU_ACCOUNTING
 172         select MODULES_USE_ELF_RELA
 173         select NO_BOOTMEM
 174         select OLD_SIGACTION
 175         select OLD_SIGSUSPEND3
 176         select SPARSE_IRQ
 177         select SYSCTL_EXCEPTION_TRACE
 178         select THREAD_INFO_IN_TASK
 179         select TTY
 180         select VIRT_CPU_ACCOUNTING
 181         select ARCH_HAS_SCALED_CPUTIME
 182         select VIRT_TO_BUS
 183         select HAVE_NMI
 184
 185
 186 config SCHED_OMIT_FRAME_POINTER
 187         def_bool y
 188
 189 config PGTABLE_LEVELS
 190         int
 191         default 5
 192
 193 source "init/Kconfig"
 194
 195 source "kernel/Kconfig.freezer"
 196
 197 source "kernel/livepatch/Kconfig"
 198
 199 menu "Processor type and features"
 200
 201 config HAVE_MARCH_Z900_FEATURES
 202         def_bool n
 203
 204 config HAVE_MARCH_Z990_FEATURES
 205         def_bool n
 206         select HAVE_MARCH_Z900_FEATURES
 207
 208 config HAVE_MARCH_Z9_109_FEATURES
 209         def_bool n
 210         select HAVE_MARCH_Z990_FEATURES
 211
 212 config HAVE_MARCH_Z10_FEATURES
 213         def_bool n
 214         select HAVE_MARCH_Z9_109_FEATURES
 215
 216 config HAVE_MARCH_Z196_FEATURES
 217         def_bool n
 218         select HAVE_MARCH_Z10_FEATURES
 219
 220 config HAVE_MARCH_ZEC12_FEATURES
 221         def_bool n
 222         select HAVE_MARCH_Z196_FEATURES
 223
 224 config HAVE_MARCH_Z13_FEATURES
 225         def_bool n
 226         select HAVE_MARCH_ZEC12_FEATURES
 227
 228 config HAVE_MARCH_Z14_FEATURES
 229         def_bool n
 230         select HAVE_MARCH_Z13_FEATURES
 231
 232 choice
 233         prompt "Processor type"
 234         default MARCH_Z196
 235
 236 config MARCH_Z900
 237         bool "IBM zSeries model z800 and z900"
 238         select HAVE_MARCH_Z900_FEATURES
 239         help
 240           Select this to enable optimizations for model z800/z900 (2064 and
 241           2066 series). This will enable some optimizations that are not
 242           available on older ESA/390 (31 Bit) only CPUs.
 243
 244 config MARCH_Z990
 245         bool "IBM zSeries model z890 and z990"
 246         select HAVE_MARCH_Z990_FEATURES
 247         help
 248           Select this to enable optimizations for model z890/z990 (2084 and
 249           2086 series). The kernel will be slightly faster but will not work
 250           on older machines.
 251
 252 config MARCH_Z9_109
 253         bool "IBM System z9"
 254         select HAVE_MARCH_Z9_109_FEATURES
 255         help
 256           Select this to enable optimizations for IBM System z9 (2094 and
 257           2096 series). The kernel will be slightly faster but will not work
 258           on older machines.
 259
 260 config MARCH_Z10
 261         bool "IBM System z10"
 262         select HAVE_MARCH_Z10_FEATURES
 263         help
 264           Select this to enable optimizations for IBM System z10 (2097 and
 265           2098 series). The kernel will be slightly faster but will not work
 266           on older machines.
 267
 268 config MARCH_Z196
 269         bool "IBM zEnterprise 114 and 196"
 270         select HAVE_MARCH_Z196_FEATURES
 271         help
 272           Select this to enable optimizations for IBM zEnterprise 114 and 196
 273           (2818 and 2817 series). The kernel will be slightly faster but will
 274           not work on older machines.
 275
 276 config MARCH_ZEC12
 277         bool "IBM zBC12 and zEC12"
 278         select HAVE_MARCH_ZEC12_FEATURES
 279         help
 280           Select this to enable optimizations for IBM zBC12 and zEC12 (2828 and
 281           2827 series). The kernel will be slightly faster but will not work on
 282           older machines.
 283
 284 config MARCH_Z13
 285         bool "IBM z13s and z13"
 286         select HAVE_MARCH_Z13_FEATURES
 287         help
 288           Select this to enable optimizations for IBM z13s and z13 (2965 and
 289           2964 series). The kernel will be slightly faster but will not work on
 290           older machines.
 291
 292 config MARCH_Z14
 293         bool "IBM z14"
 294         select HAVE_MARCH_Z14_FEATURES
 295         help
 296           Select this to enable optimizations for IBM z14 (3906 series).
 297           The kernel will be slightly faster but will not work on older
 298           machines.
 299
 300 endchoice
 301
 302 config MARCH_Z900_TUNE
 303         def_bool TUNE_Z900 || MARCH_Z900 && TUNE_DEFAULT
 304
 305 config MARCH_Z990_TUNE
 306         def_bool TUNE_Z990 || MARCH_Z990 && TUNE_DEFAULT
 307
 308 config MARCH_Z9_109_TUNE
 309         def_bool TUNE_Z9_109 || MARCH_Z9_109 && TUNE_DEFAULT
 310
 311 config MARCH_Z10_TUNE
 312         def_bool TUNE_Z10 || MARCH_Z10 && TUNE_DEFAULT
 313
 314 config MARCH_Z196_TUNE
 315         def_bool TUNE_Z196 || MARCH_Z196 && TUNE_DEFAULT
 316
 317 config MARCH_ZEC12_TUNE
 318         def_bool TUNE_ZEC12 || MARCH_ZEC12 && TUNE_DEFAULT
 319
 320 config MARCH_Z13_TUNE
 321         def_bool TUNE_Z13 || MARCH_Z13 && TUNE_DEFAULT
 322
 323 config MARCH_Z14_TUNE
 324         def_bool TUNE_Z14 || MARCH_Z14 && TUNE_DEFAULT
 325
 326 choice
 327         prompt "Tune code generation"
 328         default TUNE_DEFAULT
 329         help
 330           Cause the compiler to tune (-mtune) the generated code for a machine.
 331           This will make the code run faster on the selected machine but
 332           somewhat slower on other machines.
 333           This option only changes how the compiler emits instructions, not the
 334           selection of instructions itself, so the resulting kernel will run on
 335           all other machines.
 336
 337 config TUNE_DEFAULT
 338         bool "Default"
 339         help
 340           Tune the generated code for the target processor for which the kernel
 341           will be compiled.
 342
 343 config TUNE_Z900
 344         bool "IBM zSeries model z800 and z900"
 345
 346 config TUNE_Z990
 347         bool "IBM zSeries model z890 and z990"
 348
 349 config TUNE_Z9_109
 350         bool "IBM System z9"
 351
 352 config TUNE_Z10
 353         bool "IBM System z10"
 354
 355 config TUNE_Z196
 356         bool "IBM zEnterprise 114 and 196"
 357
 358 config TUNE_ZEC12
 359         bool "IBM zBC12 and zEC12"
 360
 361 config TUNE_Z13
 362         bool "IBM z13"
 363
 364 config TUNE_Z14
 365         bool "IBM z14"
 366
 367 endchoice
 368
 369 config 64BIT
 370         def_bool y
 371
 372 config COMPAT
 373         def_bool y
 374         prompt "Kernel support for 31 bit emulation"
 375         select COMPAT_BINFMT_ELF if BINFMT_ELF
 376         select ARCH_WANT_OLD_COMPAT_IPC
 377         select COMPAT_OLD_SIGACTION
 378         depends on MULTIUSER
 379         help
 380           Select this option if you want to enable your system kernel to
 381           handle system-calls from ELF binaries for 31 bit ESA.  This option
 382           (and some other stuff like libraries and such) is needed for
 383           executing 31 bit applications.  It is safe to say "Y".
 384
 385 config SYSVIPC_COMPAT
 386         def_bool y if COMPAT && SYSVIPC
 387
 388 config SMP
 389         def_bool y
 390         prompt "Symmetric multi-processing support"
 391         ---help---
 392           This enables support for systems with more than one CPU. If you have
 393           a system with only one CPU, like most personal computers, say N. If
 394           you have a system with more than one CPU, say Y.
 395
 396           If you say N here, the kernel will run on uni- and multiprocessor
 397           machines, but will use only one CPU of a multiprocessor machine. If
 398           you say Y here, the kernel will run on many, but not all,
 399           uniprocessor machines. On a uniprocessor machine, the kernel
 400           will run faster if you say N here.
 401
 402           See also the SMP-HOWTO available at
 403           <http://www.tldp.org/docs.html#howto>.
 404
 405           Even if you don't know what to do here, say Y.
 406
 407 config NR_CPUS
 408         int "Maximum number of CPUs (2-512)"
 409         range 2 512
 410         depends on SMP
 411         default "64"
 412         help
 413           This allows you to specify the maximum number of CPUs which this
 414           kernel will support. The maximum supported value is 512 and the
 415           minimum value which makes sense is 2.
 416
 417           This is purely to save memory - each supported CPU adds
 418           approximately sixteen kilobytes to the kernel image.
 419
 420 config HOTPLUG_CPU
 421         def_bool y
 422         prompt "Support for hot-pluggable CPUs"
 423         depends on SMP
 424         help
 425           Say Y here to be able to turn CPUs off and on. CPUs
 426           can be controlled through /sys/devices/system/cpu/cpu#.
 427           Say N if you want to disable CPU hotplug.
 428
 429 # Some NUMA nodes have memory ranges that span
 430 # other nodes.  Even though a pfn is valid and
 431 # between a node's start and end pfns, it may not
 432 # reside on that node.  See memmap_init_zone()
 433 # for details. <- They meant memory holes!
 434 config NODES_SPAN_OTHER_NODES
 435         def_bool NUMA
 436
 437 config NUMA
 438         bool "NUMA support"
 439         depends on SMP && SCHED_TOPOLOGY
 440         default n
 441         help
 442           Enable NUMA support
 443
 444           This option adds NUMA support to the kernel.
 445
 446           An operation mode can be selected by appending
 447           numa=<method> to the kernel command line.
 448
 449           The default behaviour is identical to appending numa=plain to
 450           the command line. This will create just one node with all
 451           available memory and all CPUs in it.
 452
 453 config NODES_SHIFT
 454         int "Maximum NUMA nodes (as a power of 2)"
 455         range 1 10
 456         depends on NUMA
 457         default "4"
 458         help
 459           Specify the maximum number of NUMA nodes available on the target
 460           system. Increases memory reserved to accommodate various tables.
 461
 462 menu "Select NUMA modes"
 463         depends on NUMA
 464
 465 config NUMA_EMU
 466         bool "NUMA emulation"
 467         default y
 468         help
 469           Numa emulation mode will split the available system memory into
 470           equal chunks which then are distributed over the configured number
 471           of nodes in a round-robin manner.
 472
 473           The number of fake nodes is limited by the number of available memory
 474           chunks (i.e. memory size / fake size) and the number of supported
 475           nodes in the kernel.
 476
 477           The CPUs are assigned to the nodes in a way that partially respects
 478           the original machine topology (if supported by the machine).
 479           Fair distribution of the CPUs is not guaranteed.
 480
 481 config EMU_SIZE
 482         hex "NUMA emulation memory chunk size"
 483         default 0x10000000
 484         range 0x400000 0x100000000
 485         depends on NUMA_EMU
 486         help
 487           Select the default size by which the memory is chopped and then
 488           assigned to emulated NUMA nodes.
 489
 490           This can be overridden by specifying
 491
 492           emu_size=<n>
 493
 494           on the kernel command line where also suffixes K, M, G, and T are
 495           supported.
 496
 497 endmenu
 498
 499 config SCHED_SMT
 500         def_bool n
 501
 502 config SCHED_MC
 503         def_bool n
 504
 505 config SCHED_BOOK
 506         def_bool n
 507
 508 config SCHED_DRAWER
 509         def_bool n
 510
 511 config SCHED_TOPOLOGY
 512         def_bool y
 513         prompt "Topology scheduler support"
 514         depends on SMP
 515         select SCHED_SMT
 516         select SCHED_MC
 517         select SCHED_BOOK
 518         select SCHED_DRAWER
 519         help
 520           Topology scheduler support improves the CPU scheduler's decision
 521           making when dealing with machines that have multi-threading,
 522           multiple cores or multiple books.
 523
 524 source kernel/Kconfig.preempt
 525
 526 source kernel/Kconfig.hz
 527
 528 config ARCH_RANDOM
 529         def_bool y
 530         prompt "s390 architectural random number generation API"
 531         help
 532           Enable the s390 architectural random number generation API
 533           to provide random data for all consumers within the Linux
 534           kernel.
 535
 536           When enabled the arch_random_* functions declared in linux/random.h
 537           are implemented. The implementation is based on the s390 CPACF
 538           instruction subfunction TRNG which provides a real true random
 539           number generator.
 540
 541           If unsure, say Y.
 542
 543 config KERNEL_NOBP
 544         def_bool n
 545         prompt "Enable modified branch prediction for the kernel by default"
 546         help
 547           If this option is selected the kernel will switch to a modified
 548           branch prediction mode if the firmware interface is available.
 549           The modified branch prediction mode improves the behaviour in
 550           regard to speculative execution.
 551
 552           With the option enabled the kernel parameter "nobp=0" or "nospec"
 553           can be used to run the kernel in the normal branch prediction mode.
 554
 555           With the option disabled the modified branch prediction mode is
 556           enabled with the "nobp=1" kernel parameter.
 557
 558           If unsure, say N.
 559
 560 config EXPOLINE
 561         def_bool n
 562         prompt "Avoid speculative indirect branches in the kernel"
 563         help
 564           Compile the kernel with the expoline compiler options to guard
 565           against kernel-to-user data leaks by avoiding speculative indirect
 566           branches.
 567           Requires a compiler with -mindirect-branch=thunk support for full
 568           protection. The kernel may run slower.
 569
 570           If unsure, say N.
 571
 572 choice
 573         prompt "Expoline default"
 574         depends on EXPOLINE
 575         default EXPOLINE_FULL
 576
 577 config EXPOLINE_OFF
 578         bool "spectre_v2=off"
 579
 580 config EXPOLINE_AUTO
 581         bool "spectre_v2=auto"
 582
 583 config EXPOLINE_FULL
 584         bool "spectre_v2=on"
 585
 586 endchoice
 587
 588 endmenu
 589
 590 menu "Memory setup"
 591
 592 config ARCH_SPARSEMEM_ENABLE
 593         def_bool y
 594         select SPARSEMEM_VMEMMAP_ENABLE
 595         select SPARSEMEM_VMEMMAP
 596
 597 config ARCH_SPARSEMEM_DEFAULT
 598         def_bool y
 599
 600 config ARCH_SELECT_MEMORY_MODEL
 601         def_bool y
 602
 603 config ARCH_ENABLE_MEMORY_HOTPLUG
 604         def_bool y if SPARSEMEM
 605
 606 config ARCH_ENABLE_MEMORY_HOTREMOVE
 607         def_bool y
 608
 609 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
 610         def_bool y
 611
 612 config FORCE_MAX_ZONEORDER
 613         int
 614         default "9"
 615
 616 source "mm/Kconfig"
 617
 618 config MAX_PHYSMEM_BITS
 619         int "Maximum size of supported physical memory in bits (42-53)"
 620         range 42 53
 621         default "46"
 622         help
 623           This option specifies the maximum supported size of physical memory
 624           in bits. Supported is any size between 2^42 (4TB) and 2^53 (8PB).
 625           Increasing the number of bits also increases the kernel image size.
 626           By default 46 bits (64TB) are supported.
 627
 628 config PACK_STACK
 629         def_bool y
 630         prompt "Pack kernel stack"
 631         help
 632           This option enables the compiler option -mkernel-backchain if it
 633           is available. If the option is available the compiler supports
 634           the new stack layout which dramatically reduces the minimum stack
 635           frame size. With an old compiler a non-leaf function needs a
 636           minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
 637           -mkernel-backchain the minimum size drops to 16 byte on 31 bit
 638           and 24 byte on 64 bit.
 639
 640           Say Y if you are unsure.
 641
 642 config CHECK_STACK
 643         def_bool y
 644         prompt "Detect kernel stack overflow"
 645         help
 646           This option enables the compiler option -mstack-guard and
 647           -mstack-size if they are available. If the compiler supports them
 648           it will emit additional code to each function prolog to trigger
 649           an illegal operation if the kernel stack is about to overflow.
 650
 651           Say N if you are unsure.
 652
 653 config STACK_GUARD
 654         int "Size of the guard area (128-1024)"
 655         range 128 1024
 656         depends on CHECK_STACK
 657         default "256"
 658         help
 659           This allows you to specify the size of the guard area at the lower
 660           end of the kernel stack. If the kernel stack points into the guard
 661           area on function entry an illegal operation is triggered. The size
 662           needs to be a power of 2. Please keep in mind that the size of an
 663           interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
 664           The minimum size for the stack guard should be 256 for 31 bit and
 665           512 for 64 bit.
 666
 667 config WARN_DYNAMIC_STACK
 668         def_bool n
 669         prompt "Emit compiler warnings for function with dynamic stack usage"
 670         help
 671           This option enables the compiler option -mwarn-dynamicstack. If the
 672           compiler supports this options generates warnings for functions
 673           that dynamically allocate stack space using alloca.
 674
 675           Say N if you are unsure.
 676
 677 endmenu
 678
 679 menu "I/O subsystem"
 680
 681 config QDIO
 682         def_tristate y
 683         prompt "QDIO support"
 684         ---help---
 685           This driver provides the Queued Direct I/O base support for
 686           IBM System z.
 687
 688           To compile this driver as a module, choose M here: the
 689           module will be called qdio.
 690
 691           If unsure, say Y.
 692
 693 menuconfig PCI
 694         bool "PCI support"
 695         select PCI_MSI
 696         select IOMMU_SUPPORT
 697         help
 698           Enable PCI support.
 699
 700 if PCI
 701
 702 config PCI_NR_FUNCTIONS
 703         int "Maximum number of PCI functions (1-4096)"
 704         range 1 4096
 705         default "128"
 706         help
 707           This allows you to specify the maximum number of PCI functions which
 708           this kernel will support.
 709
 710 source "drivers/pci/Kconfig"
 711
 712 endif   # PCI
 713
 714 config PCI_DOMAINS
 715         def_bool PCI
 716
 717 config HAS_IOMEM
 718         def_bool PCI
 719
 720 config IOMMU_HELPER
 721         def_bool PCI
 722
 723 config NEED_SG_DMA_LENGTH
 724         def_bool PCI
 725
 726 config NEED_DMA_MAP_STATE
 727         def_bool PCI
 728
 729 config CHSC_SCH
 730         def_tristate m
 731         prompt "Support for CHSC subchannels"
 732         help
 733           This driver allows usage of CHSC subchannels. A CHSC subchannel
 734           is usually present on LPAR only.
 735           The driver creates a device /dev/chsc, which may be used to
 736           obtain I/O configuration information about the machine and
 737           to issue asynchronous chsc commands (DANGEROUS).
 738           You will usually only want to use this interface on a special
 739           LPAR designated for system management.
 740
 741           To compile this driver as a module, choose M here: the
 742           module will be called chsc_sch.
 743
 744           If unsure, say N.
 745
 746 config SCM_BUS
 747         def_bool y
 748         prompt "SCM bus driver"
 749         help
 750           Bus driver for Storage Class Memory.
 751
 752 config EADM_SCH
 753         def_tristate m
 754         prompt "Support for EADM subchannels"
 755         depends on SCM_BUS
 756         help
 757           This driver allows usage of EADM subchannels. EADM subchannels act
 758           as a communication vehicle for SCM increments.
 759
 760           To compile this driver as a module, choose M here: the
 761           module will be called eadm_sch.
 762
 763 config VFIO_CCW
 764         def_tristate n
 765         prompt "Support for VFIO-CCW subchannels"
 766         depends on S390_CCW_IOMMU && VFIO_MDEV
 767         help
 768           This driver allows usage of I/O subchannels via VFIO-CCW.
 769
 770           To compile this driver as a module, choose M here: the
 771           module will be called vfio_ccw.
 772
 773 endmenu
 774
 775 menu "Dump support"
 776
 777 config CRASH_DUMP
 778         bool "kernel crash dumps"
 779         depends on SMP
 780         select KEXEC
 781         help
 782           Generate crash dump after being started by kexec.
 783           Crash dump kernels are loaded in the main kernel with kexec-tools
 784           into a specially reserved region and then later executed after
 785           a crash by kdump/kexec.
 786           Refer to <file:Documentation/s390/zfcpdump.txt> for more details on this.
 787           This option also enables s390 zfcpdump.
 788           See also <file:Documentation/s390/zfcpdump.txt>
 789
 790 endmenu
 791
 792 menu "Executable file formats / Emulations"
 793
 794 source "fs/Kconfig.binfmt"
 795
 796 config SECCOMP
 797         def_bool y
 798         prompt "Enable seccomp to safely compute untrusted bytecode"
 799         depends on PROC_FS
 800         help
 801           This kernel feature is useful for number crunching applications
 802           that may need to compute untrusted bytecode during their
 803           execution. By using pipes or other transports made available to
 804           the process as file descriptors supporting the read/write
 805           syscalls, it's possible to isolate those applications in
 806           their own address space using seccomp. Once seccomp is
 807           enabled via /proc/<pid>/seccomp, it cannot be disabled
 808           and the task is only allowed to execute a few safe syscalls
 809           defined by each seccomp mode.
 810
 811           If unsure, say Y.
 812
 813 endmenu
 814
 815 menu "Power Management"
 816
 817 config ARCH_HIBERNATION_POSSIBLE
 818         def_bool y
 819
 820 source "kernel/power/Kconfig"
 821
 822 endmenu
 823
 824 source "net/Kconfig"
 825
 826 config PCMCIA
 827         def_bool n
 828
 829 config CCW
 830         def_bool y
 831
 832 source "drivers/Kconfig"
 833
 834 source "fs/Kconfig"
 835
 836 source "arch/s390/Kconfig.debug"
 837
 838 source "security/Kconfig"
 839
 840 source "crypto/Kconfig"
 841
 842 source "lib/Kconfig"
 843
 844 menu "Virtualization"
 845
 846 config PFAULT
 847         def_bool y
 848         prompt "Pseudo page fault support"
 849         help
 850           Select this option, if you want to use PFAULT pseudo page fault
 851           handling under VM. If running native or in LPAR, this option
 852           has no effect. If your VM does not support PFAULT, PAGEEX
 853           pseudo page fault handling will be used.
 854           Note that VM 4.2 supports PFAULT but has a bug in its
 855           implementation that causes some problems.
 856           Everybody who wants to run Linux under VM != VM4.2 should select
 857           this option.
 858
 859 config CMM
 860         def_tristate n
 861         prompt "Cooperative memory management"
 862         help
 863           Select this option, if you want to enable the kernel interface
 864           to reduce the memory size of the system. This is accomplished
 865           by allocating pages of memory and put them "on hold". This only
 866           makes sense for a system running under VM where the unused pages
 867           will be reused by VM for other guest systems. The interface
 868           allows an external monitor to balance memory of many systems.
 869           Everybody who wants to run Linux under VM should select this
 870           option.
 871
 872 config CMM_IUCV
 873         def_bool y
 874         prompt "IUCV special message interface to cooperative memory management"
 875         depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
 876         help
 877           Select this option to enable the special message interface to
 878           the cooperative memory management.
 879
 880 config APPLDATA_BASE
 881         def_bool n
 882         prompt "Linux - VM Monitor Stream, base infrastructure"
 883         depends on PROC_FS
 884         help
 885           This provides a kernel interface for creating and updating z/VM APPLDATA
 886           monitor records. The monitor records are updated at certain time
 887           intervals, once the timer is started.
 888           Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
 889           i.e. enables or disables monitoring on the Linux side.
 890           A custom interval value (in seconds) can be written to
 891           /proc/appldata/interval.
 892
 893           Defaults are 60 seconds interval and timer off.
 894           The /proc entries can also be read from, showing the current settings.
 895
 896 config APPLDATA_MEM
 897         def_tristate m
 898         prompt "Monitor memory management statistics"
 899         depends on APPLDATA_BASE && VM_EVENT_COUNTERS
 900         help
 901           This provides memory management related data to the Linux - VM Monitor
 902           Stream, like paging/swapping rate, memory utilisation, etc.
 903           Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
 904           APPLDATA monitor record, i.e. enables or disables monitoring this record
 905           on the z/VM side.
 906
 907           Default is disabled.
 908           The /proc entry can also be read from, showing the current settings.
 909
 910           This can also be compiled as a module, which will be called
 911           appldata_mem.o.
 912
 913 config APPLDATA_OS
 914         def_tristate m
 915         prompt "Monitor OS statistics"
 916         depends on APPLDATA_BASE
 917         help
 918           This provides OS related data to the Linux - VM Monitor Stream, like
 919           CPU utilisation, etc.
 920           Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
 921           APPLDATA monitor record, i.e. enables or disables monitoring this record
 922           on the z/VM side.
 923
 924           Default is disabled.
 925           This can also be compiled as a module, which will be called
 926           appldata_os.o.
 927
 928 config APPLDATA_NET_SUM
 929         def_tristate m
 930         prompt "Monitor overall network statistics"
 931         depends on APPLDATA_BASE && NET
 932         help
 933           This provides network related data to the Linux - VM Monitor Stream,
 934           currently there is only a total sum of network I/O statistics, no
 935           per-interface data.
 936           Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
 937           APPLDATA monitor record, i.e. enables or disables monitoring this record
 938           on the z/VM side.
 939
 940           Default is disabled.
 941           This can also be compiled as a module, which will be called
 942           appldata_net_sum.o.
 943
 944 config S390_HYPFS_FS
 945         def_bool y
 946         prompt "s390 hypervisor file system support"
 947         select SYS_HYPERVISOR
 948         help
 949           This is a virtual file system intended to provide accounting
 950           information in an s390 hypervisor environment.
 951
 952 source "arch/s390/kvm/Kconfig"
 953
 954 config S390_GUEST
 955         def_bool y
 956         prompt "s390 support for virtio devices"
 957         select TTY
 958         select VIRTUALIZATION
 959         select VIRTIO
 960         select VIRTIO_CONSOLE
 961         help
 962           Enabling this option adds support for virtio based paravirtual device
 963           drivers on s390.
 964
 965           Select this option if you want to run the kernel as a guest under
 966           the KVM hypervisor.
 967
 968 endmenu