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 ARCH_HAS_ILOG2_U32
  18         def_bool n
  19
  20 config ARCH_HAS_ILOG2_U64
  21         def_bool n
  22
  23 config GENERIC_HWEIGHT
  24         def_bool y
  25
  26 config GENERIC_BUG
  27         def_bool y if BUG
  28
  29 config GENERIC_BUG_RELATIVE_POINTERS
  30         def_bool y
  31
  32 config GENERIC_LOCKBREAK
  33         def_bool y if PREEMPT
  34
  35 config PGSTE
  36         def_bool y if KVM
  37
  38 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
  39         def_bool y
  40
  41 config AUDIT_ARCH
  42         def_bool y
  43
  44 config NO_IOPORT_MAP
  45         def_bool y
  46
  47 config PCI_QUIRKS
  48         def_bool n
  49
  50 config ARCH_SUPPORTS_UPROBES
  51         def_bool y
  52
  53 config KASAN_SHADOW_OFFSET
  54         hex
  55         depends on KASAN
  56         default 0x18000000000000 if KASAN_S390_4_LEVEL_PAGING
  57         default 0x30000000000
  58
  59 config S390
  60         def_bool y
  61         select ARCH_BINFMT_ELF_STATE
  62         select ARCH_HAS_DEVMEM_IS_ALLOWED
  63         select ARCH_HAS_ELF_RANDOMIZE
  64         select ARCH_HAS_FORTIFY_SOURCE
  65         select ARCH_HAS_GCOV_PROFILE_ALL
  66         select ARCH_HAS_GIGANTIC_PAGE
  67         select ARCH_HAS_KCOV
  68         select ARCH_HAS_MEM_ENCRYPT
  69         select ARCH_HAS_PTE_SPECIAL
  70         select ARCH_HAS_SET_MEMORY
  71         select ARCH_HAS_STRICT_KERNEL_RWX
  72         select ARCH_HAS_STRICT_MODULE_RWX
  73         select ARCH_HAS_SYSCALL_WRAPPER
  74         select ARCH_HAS_UBSAN_SANITIZE_ALL
  75         select ARCH_HAVE_NMI_SAFE_CMPXCHG
  76         select ARCH_INLINE_READ_LOCK
  77         select ARCH_INLINE_READ_LOCK_BH
  78         select ARCH_INLINE_READ_LOCK_IRQ
  79         select ARCH_INLINE_READ_LOCK_IRQSAVE
  80         select ARCH_INLINE_READ_TRYLOCK
  81         select ARCH_INLINE_READ_UNLOCK
  82         select ARCH_INLINE_READ_UNLOCK_BH
  83         select ARCH_INLINE_READ_UNLOCK_IRQ
  84         select ARCH_INLINE_READ_UNLOCK_IRQRESTORE
  85         select ARCH_INLINE_SPIN_LOCK
  86         select ARCH_INLINE_SPIN_LOCK_BH
  87         select ARCH_INLINE_SPIN_LOCK_IRQ
  88         select ARCH_INLINE_SPIN_LOCK_IRQSAVE
  89         select ARCH_INLINE_SPIN_TRYLOCK
  90         select ARCH_INLINE_SPIN_TRYLOCK_BH
  91         select ARCH_INLINE_SPIN_UNLOCK
  92         select ARCH_INLINE_SPIN_UNLOCK_BH
  93         select ARCH_INLINE_SPIN_UNLOCK_IRQ
  94         select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE
  95         select ARCH_INLINE_WRITE_LOCK
  96         select ARCH_INLINE_WRITE_LOCK_BH
  97         select ARCH_INLINE_WRITE_LOCK_IRQ
  98         select ARCH_INLINE_WRITE_LOCK_IRQSAVE
  99         select ARCH_INLINE_WRITE_TRYLOCK
 100         select ARCH_INLINE_WRITE_UNLOCK
 101         select ARCH_INLINE_WRITE_UNLOCK_BH
 102         select ARCH_INLINE_WRITE_UNLOCK_IRQ
 103         select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
 104         select ARCH_KEEP_MEMBLOCK
 105         select ARCH_SAVE_PAGE_KEYS if HIBERNATION
 106         select ARCH_STACKWALK
 107         select ARCH_SUPPORTS_ATOMIC_RMW
 108         select ARCH_SUPPORTS_NUMA_BALANCING
 109         select ARCH_USE_BUILTIN_BSWAP
 110         select ARCH_USE_CMPXCHG_LOCKREF
 111         select ARCH_WANTS_DYNAMIC_TASK_STRUCT
 112         select ARCH_WANT_IPC_PARSE_VERSION
 113         select BUILDTIME_EXTABLE_SORT
 114         select CLONE_BACKWARDS2
 115         select DYNAMIC_FTRACE if FUNCTION_TRACER
 116         select GENERIC_CLOCKEVENTS
 117         select GENERIC_CPU_AUTOPROBE
 118         select GENERIC_CPU_VULNERABILITIES
 119         select GENERIC_FIND_FIRST_BIT
 120         select GENERIC_SMP_IDLE_THREAD
 121         select GENERIC_TIME_VSYSCALL
 122         select HAVE_ALIGNED_STRUCT_PAGE if SLUB
 123         select HAVE_ARCH_AUDITSYSCALL
 124         select HAVE_ARCH_JUMP_LABEL
 125         select HAVE_ARCH_JUMP_LABEL_RELATIVE
 126         select HAVE_ARCH_KASAN
 127         select HAVE_ARCH_KASAN_VMALLOC
 128         select CPU_NO_EFFICIENT_FFS if !HAVE_MARCH_Z9_109_FEATURES
 129         select HAVE_ARCH_SECCOMP_FILTER
 130         select HAVE_ARCH_SOFT_DIRTY
 131         select HAVE_ARCH_TRACEHOOK
 132         select HAVE_ARCH_TRANSPARENT_HUGEPAGE
 133         select HAVE_ARCH_VMAP_STACK
 134         select HAVE_ASM_MODVERSIONS
 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_CONTIGUOUS
 141         select HAVE_DYNAMIC_FTRACE
 142         select HAVE_DYNAMIC_FTRACE_WITH_REGS
 143         select HAVE_FAST_GUP
 144         select HAVE_EFFICIENT_UNALIGNED_ACCESS
 145         select HAVE_FENTRY
 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_UNCOMPRESSED
 157         select HAVE_KERNEL_XZ
 158         select HAVE_KPROBES
 159         select HAVE_KRETPROBES
 160         select HAVE_KVM
 161         select HAVE_LIVEPATCH
 162         select HAVE_PERF_REGS
 163         select HAVE_PERF_USER_STACK_DUMP
 164         select HAVE_MEMBLOCK_NODE_MAP
 165         select HAVE_MEMBLOCK_PHYS_MAP
 166         select HAVE_MMU_GATHER_NO_GATHER
 167         select HAVE_MOD_ARCH_SPECIFIC
 168         select HAVE_NOP_MCOUNT
 169         select HAVE_OPROFILE
 170         select HAVE_PCI
 171         select HAVE_PERF_EVENTS
 172         select HAVE_RCU_TABLE_FREE
 173         select HAVE_REGS_AND_STACK_ACCESS_API
 174         select HAVE_RELIABLE_STACKTRACE
 175         select HAVE_RSEQ
 176         select HAVE_SYSCALL_TRACEPOINTS
 177         select HAVE_VIRT_CPU_ACCOUNTING
 178         select IOMMU_HELPER             if PCI
 179         select IOMMU_SUPPORT            if PCI
 180         select MODULES_USE_ELF_RELA
 181         select NEED_DMA_MAP_STATE       if PCI
 182         select NEED_SG_DMA_LENGTH       if PCI
 183         select OLD_SIGACTION
 184         select OLD_SIGSUSPEND3
 185         select PCI_DOMAINS              if PCI
 186         select PCI_MSI                  if PCI
 187         select SPARSE_IRQ
 188         select SYSCTL_EXCEPTION_TRACE
 189         select THREAD_INFO_IN_TASK
 190         select TTY
 191         select VIRT_CPU_ACCOUNTING
 192         select ARCH_HAS_SCALED_CPUTIME
 193         select HAVE_NMI
 194         select ARCH_HAS_FORCE_DMA_UNENCRYPTED
 195         select SWIOTLB
 196         select GENERIC_ALLOCATOR
 197
 198
 199 config SCHED_OMIT_FRAME_POINTER
 200         def_bool y
 201
 202 config PGTABLE_LEVELS
 203         int
 204         default 5
 205
 206 source "kernel/livepatch/Kconfig"
 207
 208 menu "Processor type and features"
 209
 210 config HAVE_MARCH_Z900_FEATURES
 211         def_bool n
 212
 213 config HAVE_MARCH_Z990_FEATURES
 214         def_bool n
 215         select HAVE_MARCH_Z900_FEATURES
 216
 217 config HAVE_MARCH_Z9_109_FEATURES
 218         def_bool n
 219         select HAVE_MARCH_Z990_FEATURES
 220
 221 config HAVE_MARCH_Z10_FEATURES
 222         def_bool n
 223         select HAVE_MARCH_Z9_109_FEATURES
 224
 225 config HAVE_MARCH_Z196_FEATURES
 226         def_bool n
 227         select HAVE_MARCH_Z10_FEATURES
 228
 229 config HAVE_MARCH_ZEC12_FEATURES
 230         def_bool n
 231         select HAVE_MARCH_Z196_FEATURES
 232
 233 config HAVE_MARCH_Z13_FEATURES
 234         def_bool n
 235         select HAVE_MARCH_ZEC12_FEATURES
 236
 237 config HAVE_MARCH_Z14_FEATURES
 238         def_bool n
 239         select HAVE_MARCH_Z13_FEATURES
 240
 241 config HAVE_MARCH_Z15_FEATURES
 242         def_bool n
 243         select HAVE_MARCH_Z14_FEATURES
 244
 245 choice
 246         prompt "Processor type"
 247         default MARCH_Z196
 248
 249 config MARCH_Z900
 250         bool "IBM zSeries model z800 and z900"
 251         select HAVE_MARCH_Z900_FEATURES
 252         depends on $(cc-option,-march=z900)
 253         help
 254           Select this to enable optimizations for model z800/z900 (2064 and
 255           2066 series). This will enable some optimizations that are not
 256           available on older ESA/390 (31 Bit) only CPUs.
 257
 258 config MARCH_Z990
 259         bool "IBM zSeries model z890 and z990"
 260         select HAVE_MARCH_Z990_FEATURES
 261         depends on $(cc-option,-march=z990)
 262         help
 263           Select this to enable optimizations for model z890/z990 (2084 and
 264           2086 series). The kernel will be slightly faster but will not work
 265           on older machines.
 266
 267 config MARCH_Z9_109
 268         bool "IBM System z9"
 269         select HAVE_MARCH_Z9_109_FEATURES
 270         depends on $(cc-option,-march=z9-109)
 271         help
 272           Select this to enable optimizations for IBM System z9 (2094 and
 273           2096 series). The kernel will be slightly faster but will not work
 274           on older machines.
 275
 276 config MARCH_Z10
 277         bool "IBM System z10"
 278         select HAVE_MARCH_Z10_FEATURES
 279         depends on $(cc-option,-march=z10)
 280         help
 281           Select this to enable optimizations for IBM System z10 (2097 and
 282           2098 series). The kernel will be slightly faster but will not work
 283           on older machines.
 284
 285 config MARCH_Z196
 286         bool "IBM zEnterprise 114 and 196"
 287         select HAVE_MARCH_Z196_FEATURES
 288         depends on $(cc-option,-march=z196)
 289         help
 290           Select this to enable optimizations for IBM zEnterprise 114 and 196
 291           (2818 and 2817 series). The kernel will be slightly faster but will
 292           not work on older machines.
 293
 294 config MARCH_ZEC12
 295         bool "IBM zBC12 and zEC12"
 296         select HAVE_MARCH_ZEC12_FEATURES
 297         depends on $(cc-option,-march=zEC12)
 298         help
 299           Select this to enable optimizations for IBM zBC12 and zEC12 (2828 and
 300           2827 series). The kernel will be slightly faster but will not work on
 301           older machines.
 302
 303 config MARCH_Z13
 304         bool "IBM z13s and z13"
 305         select HAVE_MARCH_Z13_FEATURES
 306         depends on $(cc-option,-march=z13)
 307         help
 308           Select this to enable optimizations for IBM z13s and z13 (2965 and
 309           2964 series). The kernel will be slightly faster but will not work on
 310           older machines.
 311
 312 config MARCH_Z14
 313         bool "IBM z14 ZR1 and z14"
 314         select HAVE_MARCH_Z14_FEATURES
 315         depends on $(cc-option,-march=z14)
 316         help
 317           Select this to enable optimizations for IBM z14 ZR1 and z14 (3907
 318           and 3906 series). The kernel will be slightly faster but will not
 319           work on older machines.
 320
 321 config MARCH_Z15
 322         bool "IBM z15"
 323         select HAVE_MARCH_Z15_FEATURES
 324         depends on $(cc-option,-march=z15)
 325         help
 326           Select this to enable optimizations for IBM z15 (8562
 327           and 8561 series). The kernel will be slightly faster but will not
 328           work on older machines.
 329
 330 endchoice
 331
 332 config MARCH_Z900_TUNE
 333         def_bool TUNE_Z900 || MARCH_Z900 && TUNE_DEFAULT
 334
 335 config MARCH_Z990_TUNE
 336         def_bool TUNE_Z990 || MARCH_Z990 && TUNE_DEFAULT
 337
 338 config MARCH_Z9_109_TUNE
 339         def_bool TUNE_Z9_109 || MARCH_Z9_109 && TUNE_DEFAULT
 340
 341 config MARCH_Z10_TUNE
 342         def_bool TUNE_Z10 || MARCH_Z10 && TUNE_DEFAULT
 343
 344 config MARCH_Z196_TUNE
 345         def_bool TUNE_Z196 || MARCH_Z196 && TUNE_DEFAULT
 346
 347 config MARCH_ZEC12_TUNE
 348         def_bool TUNE_ZEC12 || MARCH_ZEC12 && TUNE_DEFAULT
 349
 350 config MARCH_Z13_TUNE
 351         def_bool TUNE_Z13 || MARCH_Z13 && TUNE_DEFAULT
 352
 353 config MARCH_Z14_TUNE
 354         def_bool TUNE_Z14 || MARCH_Z14 && TUNE_DEFAULT
 355
 356 config MARCH_Z15_TUNE
 357         def_bool TUNE_Z15 || MARCH_Z15 && TUNE_DEFAULT
 358
 359 choice
 360         prompt "Tune code generation"
 361         default TUNE_DEFAULT
 362         help
 363           Cause the compiler to tune (-mtune) the generated code for a machine.
 364           This will make the code run faster on the selected machine but
 365           somewhat slower on other machines.
 366           This option only changes how the compiler emits instructions, not the
 367           selection of instructions itself, so the resulting kernel will run on
 368           all other machines.
 369
 370 config TUNE_DEFAULT
 371         bool "Default"
 372         help
 373           Tune the generated code for the target processor for which the kernel
 374           will be compiled.
 375
 376 config TUNE_Z900
 377         bool "IBM zSeries model z800 and z900"
 378         depends on $(cc-option,-mtune=z900)
 379
 380 config TUNE_Z990
 381         bool "IBM zSeries model z890 and z990"
 382         depends on $(cc-option,-mtune=z990)
 383
 384 config TUNE_Z9_109
 385         bool "IBM System z9"
 386         depends on $(cc-option,-mtune=z9-109)
 387
 388 config TUNE_Z10
 389         bool "IBM System z10"
 390         depends on $(cc-option,-mtune=z10)
 391
 392 config TUNE_Z196
 393         bool "IBM zEnterprise 114 and 196"
 394         depends on $(cc-option,-mtune=z196)
 395
 396 config TUNE_ZEC12
 397         bool "IBM zBC12 and zEC12"
 398         depends on $(cc-option,-mtune=zEC12)
 399
 400 config TUNE_Z13
 401         bool "IBM z13s and z13"
 402         depends on $(cc-option,-mtune=z13)
 403
 404 config TUNE_Z14
 405         bool "IBM z14 ZR1 and z14"
 406         depends on $(cc-option,-mtune=z14)
 407
 408 config TUNE_Z15
 409         bool "IBM z15"
 410         depends on $(cc-option,-mtune=z15)
 411
 412 endchoice
 413
 414 config 64BIT
 415         def_bool y
 416
 417 config COMPAT
 418         def_bool y
 419         prompt "Kernel support for 31 bit emulation"
 420         select COMPAT_BINFMT_ELF if BINFMT_ELF
 421         select ARCH_WANT_OLD_COMPAT_IPC
 422         select COMPAT_OLD_SIGACTION
 423         select HAVE_UID16
 424         depends on MULTIUSER
 425         help
 426           Select this option if you want to enable your system kernel to
 427           handle system-calls from ELF binaries for 31 bit ESA.  This option
 428           (and some other stuff like libraries and such) is needed for
 429           executing 31 bit applications.  It is safe to say "Y".
 430
 431 config SYSVIPC_COMPAT
 432         def_bool y if COMPAT && SYSVIPC
 433
 434 config SMP
 435         def_bool y
 436
 437 config NR_CPUS
 438         int "Maximum number of CPUs (2-512)"
 439         range 2 512
 440         default "64"
 441         help
 442           This allows you to specify the maximum number of CPUs which this
 443           kernel will support. The maximum supported value is 512 and the
 444           minimum value which makes sense is 2.
 445
 446           This is purely to save memory - each supported CPU adds
 447           approximately sixteen kilobytes to the kernel image.
 448
 449 config HOTPLUG_CPU
 450         def_bool y
 451
 452 # Some NUMA nodes have memory ranges that span
 453 # other nodes.  Even though a pfn is valid and
 454 # between a node's start and end pfns, it may not
 455 # reside on that node.  See memmap_init_zone()
 456 # for details. <- They meant memory holes!
 457 config NODES_SPAN_OTHER_NODES
 458         def_bool NUMA
 459
 460 config NUMA
 461         bool "NUMA support"
 462         depends on SCHED_TOPOLOGY
 463         default n
 464         help
 465           Enable NUMA support
 466
 467           This option adds NUMA support to the kernel.
 468
 469           An operation mode can be selected by appending
 470           numa=<method> to the kernel command line.
 471
 472           The default behaviour is identical to appending numa=plain to
 473           the command line. This will create just one node with all
 474           available memory and all CPUs in it.
 475
 476 config NODES_SHIFT
 477         int "Maximum NUMA nodes (as a power of 2)"
 478         range 1 10
 479         depends on NUMA
 480         default "4"
 481         help
 482           Specify the maximum number of NUMA nodes available on the target
 483           system. Increases memory reserved to accommodate various tables.
 484
 485 menu "Select NUMA modes"
 486         depends on NUMA
 487
 488 config NUMA_EMU
 489         bool "NUMA emulation"
 490         default y
 491         help
 492           Numa emulation mode will split the available system memory into
 493           equal chunks which then are distributed over the configured number
 494           of nodes in a round-robin manner.
 495
 496           The number of fake nodes is limited by the number of available memory
 497           chunks (i.e. memory size / fake size) and the number of supported
 498           nodes in the kernel.
 499
 500           The CPUs are assigned to the nodes in a way that partially respects
 501           the original machine topology (if supported by the machine).
 502           Fair distribution of the CPUs is not guaranteed.
 503
 504 config EMU_SIZE
 505         hex "NUMA emulation memory chunk size"
 506         default 0x10000000
 507         range 0x400000 0x100000000
 508         depends on NUMA_EMU
 509         help
 510           Select the default size by which the memory is chopped and then
 511           assigned to emulated NUMA nodes.
 512
 513           This can be overridden by specifying
 514
 515           emu_size=<n>
 516
 517           on the kernel command line where also suffixes K, M, G, and T are
 518           supported.
 519
 520 endmenu
 521
 522 config SCHED_SMT
 523         def_bool n
 524
 525 config SCHED_MC
 526         def_bool n
 527
 528 config SCHED_BOOK
 529         def_bool n
 530
 531 config SCHED_DRAWER
 532         def_bool n
 533
 534 config SCHED_TOPOLOGY
 535         def_bool y
 536         prompt "Topology scheduler support"
 537         select SCHED_SMT
 538         select SCHED_MC
 539         select SCHED_BOOK
 540         select SCHED_DRAWER
 541         help
 542           Topology scheduler support improves the CPU scheduler's decision
 543           making when dealing with machines that have multi-threading,
 544           multiple cores or multiple books.
 545
 546 source "kernel/Kconfig.hz"
 547
 548 config KEXEC
 549         def_bool y
 550         select KEXEC_CORE
 551
 552 config KEXEC_FILE
 553         bool "kexec file based system call"
 554         select KEXEC_CORE
 555         select BUILD_BIN2C
 556         depends on CRYPTO
 557         depends on CRYPTO_SHA256
 558         depends on CRYPTO_SHA256_S390
 559         help
 560           Enable the kexec file based system call. In contrast to the normal
 561           kexec system call this system call takes file descriptors for the
 562           kernel and initramfs as arguments.
 563
 564 config ARCH_HAS_KEXEC_PURGATORY
 565         def_bool y
 566         depends on KEXEC_FILE
 567
 568 config KEXEC_SIG
 569         bool "Verify kernel signature during kexec_file_load() syscall"
 570         depends on KEXEC_FILE && MODULE_SIG_FORMAT
 571         help
 572           This option makes kernel signature verification mandatory for
 573           the kexec_file_load() syscall.
 574
 575           In addition to that option, you need to enable signature
 576           verification for the corresponding kernel image type being
 577           loaded in order for this to work.
 578
 579 config ARCH_RANDOM
 580         def_bool y
 581         prompt "s390 architectural random number generation API"
 582         help
 583           Enable the s390 architectural random number generation API
 584           to provide random data for all consumers within the Linux
 585           kernel.
 586
 587           When enabled the arch_random_* functions declared in linux/random.h
 588           are implemented. The implementation is based on the s390 CPACF
 589           instruction subfunction TRNG which provides a real true random
 590           number generator.
 591
 592           If unsure, say Y.
 593
 594 config KERNEL_NOBP
 595         def_bool n
 596         prompt "Enable modified branch prediction for the kernel by default"
 597         help
 598           If this option is selected the kernel will switch to a modified
 599           branch prediction mode if the firmware interface is available.
 600           The modified branch prediction mode improves the behaviour in
 601           regard to speculative execution.
 602
 603           With the option enabled the kernel parameter "nobp=0" or "nospec"
 604           can be used to run the kernel in the normal branch prediction mode.
 605
 606           With the option disabled the modified branch prediction mode is
 607           enabled with the "nobp=1" kernel parameter.
 608
 609           If unsure, say N.
 610
 611 config EXPOLINE
 612         def_bool n
 613         prompt "Avoid speculative indirect branches in the kernel"
 614         help
 615           Compile the kernel with the expoline compiler options to guard
 616           against kernel-to-user data leaks by avoiding speculative indirect
 617           branches.
 618           Requires a compiler with -mindirect-branch=thunk support for full
 619           protection. The kernel may run slower.
 620
 621           If unsure, say N.
 622
 623 choice
 624         prompt "Expoline default"
 625         depends on EXPOLINE
 626         default EXPOLINE_FULL
 627
 628 config EXPOLINE_OFF
 629         bool "spectre_v2=off"
 630
 631 config EXPOLINE_AUTO
 632         bool "spectre_v2=auto"
 633
 634 config EXPOLINE_FULL
 635         bool "spectre_v2=on"
 636
 637 endchoice
 638
 639 config RELOCATABLE
 640         bool "Build a relocatable kernel"
 641         select MODULE_REL_CRCS if MODVERSIONS
 642         default y
 643         help
 644           This builds a kernel image that retains relocation information
 645           so it can be loaded at an arbitrary address.
 646           The kernel is linked as a position-independent executable (PIE)
 647           and contains dynamic relocations which are processed early in the
 648           bootup process.
 649           The relocations make the kernel image about 15% larger (compressed
 650           10%), but are discarded at runtime.
 651
 652 config RANDOMIZE_BASE
 653         bool "Randomize the address of the kernel image (KASLR)"
 654         depends on RELOCATABLE
 655         default y
 656         help
 657           In support of Kernel Address Space Layout Randomization (KASLR),
 658           this randomizes the address at which the kernel image is loaded,
 659           as a security feature that deters exploit attempts relying on
 660           knowledge of the location of kernel internals.
 661
 662 endmenu
 663
 664 menu "Memory setup"
 665
 666 config ARCH_SPARSEMEM_ENABLE
 667         def_bool y
 668         select SPARSEMEM_VMEMMAP_ENABLE
 669         select SPARSEMEM_VMEMMAP
 670
 671 config ARCH_SPARSEMEM_DEFAULT
 672         def_bool y
 673
 674 config ARCH_ENABLE_MEMORY_HOTPLUG
 675         def_bool y if SPARSEMEM
 676
 677 config ARCH_ENABLE_MEMORY_HOTREMOVE
 678         def_bool y
 679
 680 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
 681         def_bool y
 682
 683 config FORCE_MAX_ZONEORDER
 684         int
 685         default "9"
 686
 687 config MAX_PHYSMEM_BITS
 688         int "Maximum size of supported physical memory in bits (42-53)"
 689         range 42 53
 690         default "46"
 691         help
 692           This option specifies the maximum supported size of physical memory
 693           in bits. Supported is any size between 2^42 (4TB) and 2^53 (8PB).
 694           Increasing the number of bits also increases the kernel image size.
 695           By default 46 bits (64TB) are supported.
 696
 697 config PACK_STACK
 698         def_bool y
 699         prompt "Pack kernel stack"
 700         help
 701           This option enables the compiler option -mkernel-backchain if it
 702           is available. If the option is available the compiler supports
 703           the new stack layout which dramatically reduces the minimum stack
 704           frame size. With an old compiler a non-leaf function needs a
 705           minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
 706           -mkernel-backchain the minimum size drops to 16 byte on 31 bit
 707           and 24 byte on 64 bit.
 708
 709           Say Y if you are unsure.
 710
 711 config CHECK_STACK
 712         def_bool y
 713         depends on !VMAP_STACK
 714         prompt "Detect kernel stack overflow"
 715         help
 716           This option enables the compiler option -mstack-guard and
 717           -mstack-size if they are available. If the compiler supports them
 718           it will emit additional code to each function prolog to trigger
 719           an illegal operation if the kernel stack is about to overflow.
 720
 721           Say N if you are unsure.
 722
 723 config STACK_GUARD
 724         int "Size of the guard area (128-1024)"
 725         range 128 1024
 726         depends on CHECK_STACK
 727         default "256"
 728         help
 729           This allows you to specify the size of the guard area at the lower
 730           end of the kernel stack. If the kernel stack points into the guard
 731           area on function entry an illegal operation is triggered. The size
 732           needs to be a power of 2. Please keep in mind that the size of an
 733           interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
 734           The minimum size for the stack guard should be 256 for 31 bit and
 735           512 for 64 bit.
 736
 737 config WARN_DYNAMIC_STACK
 738         def_bool n
 739         prompt "Emit compiler warnings for function with dynamic stack usage"
 740         help
 741           This option enables the compiler option -mwarn-dynamicstack. If the
 742           compiler supports this options generates warnings for functions
 743           that dynamically allocate stack space using alloca.
 744
 745           Say N if you are unsure.
 746
 747 endmenu
 748
 749 menu "I/O subsystem"
 750
 751 config QDIO
 752         def_tristate y
 753         prompt "QDIO support"
 754         ---help---
 755           This driver provides the Queued Direct I/O base support for
 756           IBM System z.
 757
 758           To compile this driver as a module, choose M here: the
 759           module will be called qdio.
 760
 761           If unsure, say Y.
 762
 763 if PCI
 764
 765 config PCI_NR_FUNCTIONS
 766         int "Maximum number of PCI functions (1-4096)"
 767         range 1 4096
 768         default "128"
 769         help
 770           This allows you to specify the maximum number of PCI functions which
 771           this kernel will support.
 772
 773 endif # PCI
 774
 775 config HAS_IOMEM
 776         def_bool PCI
 777
 778 config CHSC_SCH
 779         def_tristate m
 780         prompt "Support for CHSC subchannels"
 781         help
 782           This driver allows usage of CHSC subchannels. A CHSC subchannel
 783           is usually present on LPAR only.
 784           The driver creates a device /dev/chsc, which may be used to
 785           obtain I/O configuration information about the machine and
 786           to issue asynchronous chsc commands (DANGEROUS).
 787           You will usually only want to use this interface on a special
 788           LPAR designated for system management.
 789
 790           To compile this driver as a module, choose M here: the
 791           module will be called chsc_sch.
 792
 793           If unsure, say N.
 794
 795 config SCM_BUS
 796         def_bool y
 797         prompt "SCM bus driver"
 798         help
 799           Bus driver for Storage Class Memory.
 800
 801 config EADM_SCH
 802         def_tristate m
 803         prompt "Support for EADM subchannels"
 804         depends on SCM_BUS
 805         help
 806           This driver allows usage of EADM subchannels. EADM subchannels act
 807           as a communication vehicle for SCM increments.
 808
 809           To compile this driver as a module, choose M here: the
 810           module will be called eadm_sch.
 811
 812 config VFIO_CCW
 813         def_tristate n
 814         prompt "Support for VFIO-CCW subchannels"
 815         depends on S390_CCW_IOMMU && VFIO_MDEV
 816         help
 817           This driver allows usage of I/O subchannels via VFIO-CCW.
 818
 819           To compile this driver as a module, choose M here: the
 820           module will be called vfio_ccw.
 821
 822 config VFIO_AP
 823         def_tristate n
 824         prompt "VFIO support for AP devices"
 825         depends on S390_AP_IOMMU && VFIO_MDEV_DEVICE && KVM
 826         help
 827                 This driver grants access to Adjunct Processor (AP) devices
 828                 via the VFIO mediated device interface.
 829
 830                 To compile this driver as a module, choose M here: the module
 831                 will be called vfio_ap.
 832
 833 endmenu
 834
 835 menu "Dump support"
 836
 837 config CRASH_DUMP
 838         bool "kernel crash dumps"
 839         select KEXEC
 840         help
 841           Generate crash dump after being started by kexec.
 842           Crash dump kernels are loaded in the main kernel with kexec-tools
 843           into a specially reserved region and then later executed after
 844           a crash by kdump/kexec.
 845           Refer to <file:Documentation/s390/zfcpdump.rst> for more details on this.
 846           This option also enables s390 zfcpdump.
 847           See also <file:Documentation/s390/zfcpdump.rst>
 848
 849 endmenu
 850
 851 config SECCOMP
 852         def_bool y
 853         prompt "Enable seccomp to safely compute untrusted bytecode"
 854         depends on PROC_FS
 855         help
 856           This kernel feature is useful for number crunching applications
 857           that may need to compute untrusted bytecode during their
 858           execution. By using pipes or other transports made available to
 859           the process as file descriptors supporting the read/write
 860           syscalls, it's possible to isolate those applications in
 861           their own address space using seccomp. Once seccomp is
 862           enabled via /proc/<pid>/seccomp, it cannot be disabled
 863           and the task is only allowed to execute a few safe syscalls
 864           defined by each seccomp mode.
 865
 866           If unsure, say Y.
 867
 868 menu "Power Management"
 869
 870 config ARCH_HIBERNATION_POSSIBLE
 871         def_bool y
 872
 873 source "kernel/power/Kconfig"
 874
 875 endmenu
 876
 877 config CCW
 878         def_bool y
 879
 880 config HAVE_PNETID
 881         tristate
 882         default (SMC || CCWGROUP)
 883
 884 menu "Virtualization"
 885
 886 config PROTECTED_VIRTUALIZATION_GUEST
 887         def_bool n
 888         prompt "Protected virtualization guest support"
 889         help
 890           Select this option, if you want to be able to run this
 891           kernel as a protected virtualization KVM guest.
 892           Protected virtualization capable machines have a mini hypervisor
 893           located at machine level (an ultravisor). With help of the
 894           Ultravisor, KVM will be able to run "protected" VMs, special
 895           VMs whose memory and management data are unavailable to KVM.
 896
 897 config PFAULT
 898         def_bool y
 899         prompt "Pseudo page fault support"
 900         help
 901           Select this option, if you want to use PFAULT pseudo page fault
 902           handling under VM. If running native or in LPAR, this option
 903           has no effect. If your VM does not support PFAULT, PAGEEX
 904           pseudo page fault handling will be used.
 905           Note that VM 4.2 supports PFAULT but has a bug in its
 906           implementation that causes some problems.
 907           Everybody who wants to run Linux under VM != VM4.2 should select
 908           this option.
 909
 910 config CMM
 911         def_tristate n
 912         prompt "Cooperative memory management"
 913         help
 914           Select this option, if you want to enable the kernel interface
 915           to reduce the memory size of the system. This is accomplished
 916           by allocating pages of memory and put them "on hold". This only
 917           makes sense for a system running under VM where the unused pages
 918           will be reused by VM for other guest systems. The interface
 919           allows an external monitor to balance memory of many systems.
 920           Everybody who wants to run Linux under VM should select this
 921           option.
 922
 923 config CMM_IUCV
 924         def_bool y
 925         prompt "IUCV special message interface to cooperative memory management"
 926         depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
 927         help
 928           Select this option to enable the special message interface to
 929           the cooperative memory management.
 930
 931 config APPLDATA_BASE
 932         def_bool n
 933         prompt "Linux - VM Monitor Stream, base infrastructure"
 934         depends on PROC_FS
 935         help
 936           This provides a kernel interface for creating and updating z/VM APPLDATA
 937           monitor records. The monitor records are updated at certain time
 938           intervals, once the timer is started.
 939           Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
 940           i.e. enables or disables monitoring on the Linux side.
 941           A custom interval value (in seconds) can be written to
 942           /proc/appldata/interval.
 943
 944           Defaults are 60 seconds interval and timer off.
 945           The /proc entries can also be read from, showing the current settings.
 946
 947 config APPLDATA_MEM
 948         def_tristate m
 949         prompt "Monitor memory management statistics"
 950         depends on APPLDATA_BASE && VM_EVENT_COUNTERS
 951         help
 952           This provides memory management related data to the Linux - VM Monitor
 953           Stream, like paging/swapping rate, memory utilisation, etc.
 954           Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
 955           APPLDATA monitor record, i.e. enables or disables monitoring this record
 956           on the z/VM side.
 957
 958           Default is disabled.
 959           The /proc entry can also be read from, showing the current settings.
 960
 961           This can also be compiled as a module, which will be called
 962           appldata_mem.o.
 963
 964 config APPLDATA_OS
 965         def_tristate m
 966         prompt "Monitor OS statistics"
 967         depends on APPLDATA_BASE
 968         help
 969           This provides OS related data to the Linux - VM Monitor Stream, like
 970           CPU utilisation, etc.
 971           Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
 972           APPLDATA monitor record, i.e. enables or disables monitoring this record
 973           on the z/VM side.
 974
 975           Default is disabled.
 976           This can also be compiled as a module, which will be called
 977           appldata_os.o.
 978
 979 config APPLDATA_NET_SUM
 980         def_tristate m
 981         prompt "Monitor overall network statistics"
 982         depends on APPLDATA_BASE && NET
 983         help
 984           This provides network related data to the Linux - VM Monitor Stream,
 985           currently there is only a total sum of network I/O statistics, no
 986           per-interface data.
 987           Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
 988           APPLDATA monitor record, i.e. enables or disables monitoring this record
 989           on the z/VM side.
 990
 991           Default is disabled.
 992           This can also be compiled as a module, which will be called
 993           appldata_net_sum.o.
 994
 995 config S390_HYPFS_FS
 996         def_bool y
 997         prompt "s390 hypervisor file system support"
 998         select SYS_HYPERVISOR
 999         help
1000           This is a virtual file system intended to provide accounting
1001           information in an s390 hypervisor environment.
1002
1003 source "arch/s390/kvm/Kconfig"
1004
1005 config S390_GUEST
1006         def_bool y
1007         prompt "s390 support for virtio devices"
1008         select TTY
1009         select VIRTUALIZATION
1010         select VIRTIO
1011         select VIRTIO_CONSOLE
1012         help
1013           Enabling this option adds support for virtio based paravirtual device
1014           drivers on s390.
1015
1016           Select this option if you want to run the kernel as a guest under
1017           the KVM hypervisor.
1018
1019 endmenu
1020
1021 menu "Selftests"
1022
1023 config S390_UNWIND_SELFTEST
1024         def_tristate n
1025         prompt "Test unwind functions"
1026         help
1027           This option enables s390 specific stack unwinder testing kernel
1028           module. This option is not useful for distributions or general
1029           kernels, but only for kernel developers working on architecture code.
1030
1031           Say N if you are unsure.
1032
1033 endmenu