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 PREEMPTION
  34
  35 config PGSTE
  36         def_bool y if KVM
  37
  38 config AUDIT_ARCH
  39         def_bool y
  40
  41 config NO_IOPORT_MAP
  42         def_bool y
  43
  44 config PCI_QUIRKS
  45         def_bool n
  46
  47 config ARCH_SUPPORTS_UPROBES
  48         def_bool y
  49
  50 config KASAN_SHADOW_OFFSET
  51         hex
  52         depends on KASAN
  53         default 0x18000000000000
  54
  55 config S390
  56         def_bool y
  57         select ARCH_BINFMT_ELF_STATE
  58         select ARCH_HAS_DEBUG_VM_PGTABLE
  59         select ARCH_HAS_DEBUG_WX
  60         select ARCH_HAS_DEVMEM_IS_ALLOWED
  61         select ARCH_HAS_ELF_RANDOMIZE
  62         select ARCH_HAS_FORTIFY_SOURCE
  63         select ARCH_HAS_GCOV_PROFILE_ALL
  64         select ARCH_HAS_GIGANTIC_PAGE
  65         select ARCH_HAS_KCOV
  66         select ARCH_HAS_MEM_ENCRYPT
  67         select ARCH_HAS_PTE_SPECIAL
  68         select ARCH_HAS_SET_MEMORY
  69         select ARCH_HAS_STRICT_KERNEL_RWX
  70         select ARCH_HAS_STRICT_MODULE_RWX
  71         select ARCH_HAS_SYSCALL_WRAPPER
  72         select ARCH_HAS_UBSAN_SANITIZE_ALL
  73         select ARCH_HAS_VDSO_DATA
  74         select ARCH_HAVE_NMI_SAFE_CMPXCHG
  75         select ARCH_INLINE_READ_LOCK
  76         select ARCH_INLINE_READ_LOCK_BH
  77         select ARCH_INLINE_READ_LOCK_IRQ
  78         select ARCH_INLINE_READ_LOCK_IRQSAVE
  79         select ARCH_INLINE_READ_TRYLOCK
  80         select ARCH_INLINE_READ_UNLOCK
  81         select ARCH_INLINE_READ_UNLOCK_BH
  82         select ARCH_INLINE_READ_UNLOCK_IRQ
  83         select ARCH_INLINE_READ_UNLOCK_IRQRESTORE
  84         select ARCH_INLINE_SPIN_LOCK
  85         select ARCH_INLINE_SPIN_LOCK_BH
  86         select ARCH_INLINE_SPIN_LOCK_IRQ
  87         select ARCH_INLINE_SPIN_LOCK_IRQSAVE
  88         select ARCH_INLINE_SPIN_TRYLOCK
  89         select ARCH_INLINE_SPIN_TRYLOCK_BH
  90         select ARCH_INLINE_SPIN_UNLOCK
  91         select ARCH_INLINE_SPIN_UNLOCK_BH
  92         select ARCH_INLINE_SPIN_UNLOCK_IRQ
  93         select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE
  94         select ARCH_INLINE_WRITE_LOCK
  95         select ARCH_INLINE_WRITE_LOCK_BH
  96         select ARCH_INLINE_WRITE_LOCK_IRQ
  97         select ARCH_INLINE_WRITE_LOCK_IRQSAVE
  98         select ARCH_INLINE_WRITE_TRYLOCK
  99         select ARCH_INLINE_WRITE_UNLOCK
 100         select ARCH_INLINE_WRITE_UNLOCK_BH
 101         select ARCH_INLINE_WRITE_UNLOCK_IRQ
 102         select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
 103         select ARCH_STACKWALK
 104         select ARCH_SUPPORTS_ATOMIC_RMW
 105         select ARCH_SUPPORTS_DEBUG_PAGEALLOC
 106         select ARCH_SUPPORTS_NUMA_BALANCING
 107         select ARCH_USE_BUILTIN_BSWAP
 108         select ARCH_USE_CMPXCHG_LOCKREF
 109         select ARCH_WANTS_DYNAMIC_TASK_STRUCT
 110         select ARCH_WANT_DEFAULT_BPF_JIT
 111         select ARCH_WANT_IPC_PARSE_VERSION
 112         select BUILDTIME_TABLE_SORT
 113         select CLONE_BACKWARDS2
 114         select DMA_OPS if PCI
 115         select DYNAMIC_FTRACE if FUNCTION_TRACER
 116         select GENERIC_CPU_AUTOPROBE
 117         select GENERIC_CPU_VULNERABILITIES
 118         select GENERIC_FIND_FIRST_BIT
 119         select GENERIC_GETTIMEOFDAY
 120         select GENERIC_PTDUMP
 121         select GENERIC_SMP_IDLE_THREAD
 122         select GENERIC_TIME_VSYSCALL
 123         select HAVE_ALIGNED_STRUCT_PAGE if SLUB
 124         select HAVE_ARCH_AUDITSYSCALL
 125         select HAVE_ARCH_JUMP_LABEL
 126         select HAVE_ARCH_JUMP_LABEL_RELATIVE
 127         select HAVE_ARCH_KASAN
 128         select HAVE_ARCH_KASAN_VMALLOC
 129         select CPU_NO_EFFICIENT_FFS if !HAVE_MARCH_Z9_109_FEATURES
 130         select HAVE_ARCH_SECCOMP_FILTER
 131         select HAVE_ARCH_SOFT_DIRTY
 132         select HAVE_ARCH_TRACEHOOK
 133         select HAVE_ARCH_TRANSPARENT_HUGEPAGE
 134         select HAVE_ARCH_VMAP_STACK
 135         select HAVE_ASM_MODVERSIONS
 136         select HAVE_EBPF_JIT if PACK_STACK && HAVE_MARCH_Z196_FEATURES
 137         select HAVE_CMPXCHG_DOUBLE
 138         select HAVE_CMPXCHG_LOCAL
 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_ERROR_INJECTION
 148         select HAVE_FUNCTION_GRAPH_TRACER
 149         select HAVE_FUNCTION_TRACER
 150         select HAVE_FUTEX_CMPXCHG if FUTEX
 151         select HAVE_GCC_PLUGINS
 152         select HAVE_GENERIC_VDSO
 153         select HAVE_IRQ_EXIT_ON_IRQ_STACK
 154         select HAVE_KERNEL_BZIP2
 155         select HAVE_KERNEL_GZIP
 156         select HAVE_KERNEL_LZ4
 157         select HAVE_KERNEL_LZMA
 158         select HAVE_KERNEL_LZO
 159         select HAVE_KERNEL_UNCOMPRESSED
 160         select HAVE_KERNEL_XZ
 161         select HAVE_KPROBES
 162         select HAVE_KPROBES_ON_FTRACE
 163         select HAVE_KRETPROBES
 164         select HAVE_KVM
 165         select HAVE_LIVEPATCH
 166         select HAVE_PERF_REGS
 167         select HAVE_PERF_USER_STACK_DUMP
 168         select HAVE_MEMBLOCK_PHYS_MAP
 169         select MMU_GATHER_NO_GATHER
 170         select HAVE_MOD_ARCH_SPECIFIC
 171         select HAVE_NOP_MCOUNT
 172         select HAVE_OPROFILE
 173         select HAVE_PCI
 174         select HAVE_PERF_EVENTS
 175         select MMU_GATHER_RCU_TABLE_FREE
 176         select HAVE_REGS_AND_STACK_ACCESS_API
 177         select HAVE_RELIABLE_STACKTRACE
 178         select HAVE_RSEQ
 179         select HAVE_SYSCALL_TRACEPOINTS
 180         select HAVE_VIRT_CPU_ACCOUNTING
 181         select HAVE_VIRT_CPU_ACCOUNTING_IDLE
 182         select IOMMU_HELPER             if PCI
 183         select IOMMU_SUPPORT            if PCI
 184         select MODULES_USE_ELF_RELA
 185         select NEED_DMA_MAP_STATE       if PCI
 186         select NEED_SG_DMA_LENGTH       if PCI
 187         select OLD_SIGACTION
 188         select OLD_SIGSUSPEND3
 189         select PCI_DOMAINS              if PCI
 190         select PCI_MSI                  if PCI
 191         select PCI_MSI_ARCH_FALLBACKS   if PCI_MSI
 192         select SPARSE_IRQ
 193         select SYSCTL_EXCEPTION_TRACE
 194         select THREAD_INFO_IN_TASK
 195         select TTY
 196         select VIRT_CPU_ACCOUNTING
 197         select ARCH_HAS_SCALED_CPUTIME
 198         select HAVE_NMI
 199         select ARCH_HAS_FORCE_DMA_UNENCRYPTED
 200         select SWIOTLB
 201         select GENERIC_ALLOCATOR
 202         imply IMA_SECURE_AND_OR_TRUSTED_BOOT
 203
 204
 205 config SCHED_OMIT_FRAME_POINTER
 206         def_bool y
 207
 208 config PGTABLE_LEVELS
 209         int
 210         default 5
 211
 212 source "kernel/livepatch/Kconfig"
 213
 214 menu "Processor type and features"
 215
 216 config HAVE_MARCH_Z900_FEATURES
 217         def_bool n
 218
 219 config HAVE_MARCH_Z990_FEATURES
 220         def_bool n
 221         select HAVE_MARCH_Z900_FEATURES
 222
 223 config HAVE_MARCH_Z9_109_FEATURES
 224         def_bool n
 225         select HAVE_MARCH_Z990_FEATURES
 226
 227 config HAVE_MARCH_Z10_FEATURES
 228         def_bool n
 229         select HAVE_MARCH_Z9_109_FEATURES
 230
 231 config HAVE_MARCH_Z196_FEATURES
 232         def_bool n
 233         select HAVE_MARCH_Z10_FEATURES
 234
 235 config HAVE_MARCH_ZEC12_FEATURES
 236         def_bool n
 237         select HAVE_MARCH_Z196_FEATURES
 238
 239 config HAVE_MARCH_Z13_FEATURES
 240         def_bool n
 241         select HAVE_MARCH_ZEC12_FEATURES
 242
 243 config HAVE_MARCH_Z14_FEATURES
 244         def_bool n
 245         select HAVE_MARCH_Z13_FEATURES
 246
 247 config HAVE_MARCH_Z15_FEATURES
 248         def_bool n
 249         select HAVE_MARCH_Z14_FEATURES
 250
 251 choice
 252         prompt "Processor type"
 253         default MARCH_Z196
 254
 255 config MARCH_Z900
 256         bool "IBM zSeries model z800 and z900"
 257         select HAVE_MARCH_Z900_FEATURES
 258         depends on $(cc-option,-march=z900)
 259         help
 260           Select this to enable optimizations for model z800/z900 (2064 and
 261           2066 series). This will enable some optimizations that are not
 262           available on older ESA/390 (31 Bit) only CPUs.
 263
 264 config MARCH_Z990
 265         bool "IBM zSeries model z890 and z990"
 266         select HAVE_MARCH_Z990_FEATURES
 267         depends on $(cc-option,-march=z990)
 268         help
 269           Select this to enable optimizations for model z890/z990 (2084 and
 270           2086 series). The kernel will be slightly faster but will not work
 271           on older machines.
 272
 273 config MARCH_Z9_109
 274         bool "IBM System z9"
 275         select HAVE_MARCH_Z9_109_FEATURES
 276         depends on $(cc-option,-march=z9-109)
 277         help
 278           Select this to enable optimizations for IBM System z9 (2094 and
 279           2096 series). The kernel will be slightly faster but will not work
 280           on older machines.
 281
 282 config MARCH_Z10
 283         bool "IBM System z10"
 284         select HAVE_MARCH_Z10_FEATURES
 285         depends on $(cc-option,-march=z10)
 286         help
 287           Select this to enable optimizations for IBM System z10 (2097 and
 288           2098 series). The kernel will be slightly faster but will not work
 289           on older machines.
 290
 291 config MARCH_Z196
 292         bool "IBM zEnterprise 114 and 196"
 293         select HAVE_MARCH_Z196_FEATURES
 294         depends on $(cc-option,-march=z196)
 295         help
 296           Select this to enable optimizations for IBM zEnterprise 114 and 196
 297           (2818 and 2817 series). The kernel will be slightly faster but will
 298           not work on older machines.
 299
 300 config MARCH_ZEC12
 301         bool "IBM zBC12 and zEC12"
 302         select HAVE_MARCH_ZEC12_FEATURES
 303         depends on $(cc-option,-march=zEC12)
 304         help
 305           Select this to enable optimizations for IBM zBC12 and zEC12 (2828 and
 306           2827 series). The kernel will be slightly faster but will not work on
 307           older machines.
 308
 309 config MARCH_Z13
 310         bool "IBM z13s and z13"
 311         select HAVE_MARCH_Z13_FEATURES
 312         depends on $(cc-option,-march=z13)
 313         help
 314           Select this to enable optimizations for IBM z13s and z13 (2965 and
 315           2964 series). The kernel will be slightly faster but will not work on
 316           older machines.
 317
 318 config MARCH_Z14
 319         bool "IBM z14 ZR1 and z14"
 320         select HAVE_MARCH_Z14_FEATURES
 321         depends on $(cc-option,-march=z14)
 322         help
 323           Select this to enable optimizations for IBM z14 ZR1 and z14 (3907
 324           and 3906 series). The kernel will be slightly faster but will not
 325           work on older machines.
 326
 327 config MARCH_Z15
 328         bool "IBM z15"
 329         select HAVE_MARCH_Z15_FEATURES
 330         depends on $(cc-option,-march=z15)
 331         help
 332           Select this to enable optimizations for IBM z15 (8562
 333           and 8561 series). The kernel will be slightly faster but will not
 334           work on older machines.
 335
 336 endchoice
 337
 338 config MARCH_Z900_TUNE
 339         def_bool TUNE_Z900 || MARCH_Z900 && TUNE_DEFAULT
 340
 341 config MARCH_Z990_TUNE
 342         def_bool TUNE_Z990 || MARCH_Z990 && TUNE_DEFAULT
 343
 344 config MARCH_Z9_109_TUNE
 345         def_bool TUNE_Z9_109 || MARCH_Z9_109 && TUNE_DEFAULT
 346
 347 config MARCH_Z10_TUNE
 348         def_bool TUNE_Z10 || MARCH_Z10 && TUNE_DEFAULT
 349
 350 config MARCH_Z196_TUNE
 351         def_bool TUNE_Z196 || MARCH_Z196 && TUNE_DEFAULT
 352
 353 config MARCH_ZEC12_TUNE
 354         def_bool TUNE_ZEC12 || MARCH_ZEC12 && TUNE_DEFAULT
 355
 356 config MARCH_Z13_TUNE
 357         def_bool TUNE_Z13 || MARCH_Z13 && TUNE_DEFAULT
 358
 359 config MARCH_Z14_TUNE
 360         def_bool TUNE_Z14 || MARCH_Z14 && TUNE_DEFAULT
 361
 362 config MARCH_Z15_TUNE
 363         def_bool TUNE_Z15 || MARCH_Z15 && TUNE_DEFAULT
 364
 365 choice
 366         prompt "Tune code generation"
 367         default TUNE_DEFAULT
 368         help
 369           Cause the compiler to tune (-mtune) the generated code for a machine.
 370           This will make the code run faster on the selected machine but
 371           somewhat slower on other machines.
 372           This option only changes how the compiler emits instructions, not the
 373           selection of instructions itself, so the resulting kernel will run on
 374           all other machines.
 375
 376 config TUNE_DEFAULT
 377         bool "Default"
 378         help
 379           Tune the generated code for the target processor for which the kernel
 380           will be compiled.
 381
 382 config TUNE_Z900
 383         bool "IBM zSeries model z800 and z900"
 384         depends on $(cc-option,-mtune=z900)
 385
 386 config TUNE_Z990
 387         bool "IBM zSeries model z890 and z990"
 388         depends on $(cc-option,-mtune=z990)
 389
 390 config TUNE_Z9_109
 391         bool "IBM System z9"
 392         depends on $(cc-option,-mtune=z9-109)
 393
 394 config TUNE_Z10
 395         bool "IBM System z10"
 396         depends on $(cc-option,-mtune=z10)
 397
 398 config TUNE_Z196
 399         bool "IBM zEnterprise 114 and 196"
 400         depends on $(cc-option,-mtune=z196)
 401
 402 config TUNE_ZEC12
 403         bool "IBM zBC12 and zEC12"
 404         depends on $(cc-option,-mtune=zEC12)
 405
 406 config TUNE_Z13
 407         bool "IBM z13s and z13"
 408         depends on $(cc-option,-mtune=z13)
 409
 410 config TUNE_Z14
 411         bool "IBM z14 ZR1 and z14"
 412         depends on $(cc-option,-mtune=z14)
 413
 414 config TUNE_Z15
 415         bool "IBM z15"
 416         depends on $(cc-option,-mtune=z15)
 417
 418 endchoice
 419
 420 config 64BIT
 421         def_bool y
 422
 423 config COMPAT
 424         def_bool y
 425         prompt "Kernel support for 31 bit emulation"
 426         select COMPAT_BINFMT_ELF if BINFMT_ELF
 427         select ARCH_WANT_OLD_COMPAT_IPC
 428         select COMPAT_OLD_SIGACTION
 429         select HAVE_UID16
 430         depends on MULTIUSER
 431         help
 432           Select this option if you want to enable your system kernel to
 433           handle system-calls from ELF binaries for 31 bit ESA.  This option
 434           (and some other stuff like libraries and such) is needed for
 435           executing 31 bit applications.  It is safe to say "Y".
 436
 437 config SYSVIPC_COMPAT
 438         def_bool y if COMPAT && SYSVIPC
 439
 440 config SMP
 441         def_bool y
 442
 443 config NR_CPUS
 444         int "Maximum number of CPUs (2-512)"
 445         range 2 512
 446         default "64"
 447         help
 448           This allows you to specify the maximum number of CPUs which this
 449           kernel will support. The maximum supported value is 512 and the
 450           minimum value which makes sense is 2.
 451
 452           This is purely to save memory - each supported CPU adds
 453           approximately sixteen kilobytes to the kernel image.
 454
 455 config HOTPLUG_CPU
 456         def_bool y
 457
 458 config NUMA
 459         bool "NUMA support"
 460         depends on SCHED_TOPOLOGY
 461         default n
 462         help
 463           Enable NUMA support
 464
 465           This option adds NUMA support to the kernel.
 466
 467 config NODES_SHIFT
 468         int
 469         depends on NEED_MULTIPLE_NODES
 470         default "1"
 471
 472 config SCHED_SMT
 473         def_bool n
 474
 475 config SCHED_MC
 476         def_bool n
 477
 478 config SCHED_BOOK
 479         def_bool n
 480
 481 config SCHED_DRAWER
 482         def_bool n
 483
 484 config SCHED_TOPOLOGY
 485         def_bool y
 486         prompt "Topology scheduler support"
 487         select SCHED_SMT
 488         select SCHED_MC
 489         select SCHED_BOOK
 490         select SCHED_DRAWER
 491         help
 492           Topology scheduler support improves the CPU scheduler's decision
 493           making when dealing with machines that have multi-threading,
 494           multiple cores or multiple books.
 495
 496 source "kernel/Kconfig.hz"
 497
 498 config KEXEC
 499         def_bool y
 500         select KEXEC_CORE
 501
 502 config KEXEC_FILE
 503         bool "kexec file based system call"
 504         select KEXEC_CORE
 505         select BUILD_BIN2C
 506         depends on CRYPTO
 507         depends on CRYPTO_SHA256
 508         depends on CRYPTO_SHA256_S390
 509         help
 510           Enable the kexec file based system call. In contrast to the normal
 511           kexec system call this system call takes file descriptors for the
 512           kernel and initramfs as arguments.
 513
 514 config ARCH_HAS_KEXEC_PURGATORY
 515         def_bool y
 516         depends on KEXEC_FILE
 517
 518 config KEXEC_SIG
 519         bool "Verify kernel signature during kexec_file_load() syscall"
 520         depends on KEXEC_FILE && MODULE_SIG_FORMAT
 521         help
 522           This option makes kernel signature verification mandatory for
 523           the kexec_file_load() syscall.
 524
 525           In addition to that option, you need to enable signature
 526           verification for the corresponding kernel image type being
 527           loaded in order for this to work.
 528
 529 config ARCH_RANDOM
 530         def_bool y
 531         prompt "s390 architectural random number generation API"
 532         help
 533           Enable the s390 architectural random number generation API
 534           to provide random data for all consumers within the Linux
 535           kernel.
 536
 537           When enabled the arch_random_* functions declared in linux/random.h
 538           are implemented. The implementation is based on the s390 CPACF
 539           instruction subfunction TRNG which provides a real true random
 540           number generator.
 541
 542           If unsure, say Y.
 543
 544 config KERNEL_NOBP
 545         def_bool n
 546         prompt "Enable modified branch prediction for the kernel by default"
 547         help
 548           If this option is selected the kernel will switch to a modified
 549           branch prediction mode if the firmware interface is available.
 550           The modified branch prediction mode improves the behaviour in
 551           regard to speculative execution.
 552
 553           With the option enabled the kernel parameter "nobp=0" or "nospec"
 554           can be used to run the kernel in the normal branch prediction mode.
 555
 556           With the option disabled the modified branch prediction mode is
 557           enabled with the "nobp=1" kernel parameter.
 558
 559           If unsure, say N.
 560
 561 config EXPOLINE
 562         def_bool n
 563         prompt "Avoid speculative indirect branches in the kernel"
 564         help
 565           Compile the kernel with the expoline compiler options to guard
 566           against kernel-to-user data leaks by avoiding speculative indirect
 567           branches.
 568           Requires a compiler with -mindirect-branch=thunk support for full
 569           protection. The kernel may run slower.
 570
 571           If unsure, say N.
 572
 573 choice
 574         prompt "Expoline default"
 575         depends on EXPOLINE
 576         default EXPOLINE_FULL
 577
 578 config EXPOLINE_OFF
 579         bool "spectre_v2=off"
 580
 581 config EXPOLINE_AUTO
 582         bool "spectre_v2=auto"
 583
 584 config EXPOLINE_FULL
 585         bool "spectre_v2=on"
 586
 587 endchoice
 588
 589 config RELOCATABLE
 590         bool "Build a relocatable kernel"
 591         select MODULE_REL_CRCS if MODVERSIONS
 592         default y
 593         help
 594           This builds a kernel image that retains relocation information
 595           so it can be loaded at an arbitrary address.
 596           The kernel is linked as a position-independent executable (PIE)
 597           and contains dynamic relocations which are processed early in the
 598           bootup process.
 599           The relocations make the kernel image about 15% larger (compressed
 600           10%), but are discarded at runtime.
 601
 602 config RANDOMIZE_BASE
 603         bool "Randomize the address of the kernel image (KASLR)"
 604         depends on RELOCATABLE
 605         default y
 606         help
 607           In support of Kernel Address Space Layout Randomization (KASLR),
 608           this randomizes the address at which the kernel image is loaded,
 609           as a security feature that deters exploit attempts relying on
 610           knowledge of the location of kernel internals.
 611
 612 endmenu
 613
 614 menu "Memory setup"
 615
 616 config ARCH_SPARSEMEM_ENABLE
 617         def_bool y
 618         select SPARSEMEM_VMEMMAP_ENABLE
 619         select SPARSEMEM_VMEMMAP
 620
 621 config ARCH_SPARSEMEM_DEFAULT
 622         def_bool y
 623
 624 config ARCH_ENABLE_MEMORY_HOTPLUG
 625         def_bool y if SPARSEMEM
 626
 627 config ARCH_ENABLE_MEMORY_HOTREMOVE
 628         def_bool y
 629
 630 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
 631         def_bool y
 632
 633 config MAX_PHYSMEM_BITS
 634         int "Maximum size of supported physical memory in bits (42-53)"
 635         range 42 53
 636         default "46"
 637         help
 638           This option specifies the maximum supported size of physical memory
 639           in bits. Supported is any size between 2^42 (4TB) and 2^53 (8PB).
 640           Increasing the number of bits also increases the kernel image size.
 641           By default 46 bits (64TB) are supported.
 642
 643 config PACK_STACK
 644         def_bool y
 645         prompt "Pack kernel stack"
 646         help
 647           This option enables the compiler option -mkernel-backchain if it
 648           is available. If the option is available the compiler supports
 649           the new stack layout which dramatically reduces the minimum stack
 650           frame size. With an old compiler a non-leaf function needs a
 651           minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
 652           -mkernel-backchain the minimum size drops to 16 byte on 31 bit
 653           and 24 byte on 64 bit.
 654
 655           Say Y if you are unsure.
 656
 657 config CHECK_STACK
 658         def_bool y
 659         depends on !VMAP_STACK
 660         prompt "Detect kernel stack overflow"
 661         help
 662           This option enables the compiler option -mstack-guard and
 663           -mstack-size if they are available. If the compiler supports them
 664           it will emit additional code to each function prolog to trigger
 665           an illegal operation if the kernel stack is about to overflow.
 666
 667           Say N if you are unsure.
 668
 669 config STACK_GUARD
 670         int "Size of the guard area (128-1024)"
 671         range 128 1024
 672         depends on CHECK_STACK
 673         default "256"
 674         help
 675           This allows you to specify the size of the guard area at the lower
 676           end of the kernel stack. If the kernel stack points into the guard
 677           area on function entry an illegal operation is triggered. The size
 678           needs to be a power of 2. Please keep in mind that the size of an
 679           interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
 680           The minimum size for the stack guard should be 256 for 31 bit and
 681           512 for 64 bit.
 682
 683 config WARN_DYNAMIC_STACK
 684         def_bool n
 685         prompt "Emit compiler warnings for function with dynamic stack usage"
 686         help
 687           This option enables the compiler option -mwarn-dynamicstack. If the
 688           compiler supports this options generates warnings for functions
 689           that dynamically allocate stack space using alloca.
 690
 691           Say N if you are unsure.
 692
 693 endmenu
 694
 695 menu "I/O subsystem"
 696
 697 config QDIO
 698         def_tristate y
 699         prompt "QDIO support"
 700         help
 701           This driver provides the Queued Direct I/O base support for
 702           IBM System z.
 703
 704           To compile this driver as a module, choose M here: the
 705           module will be called qdio.
 706
 707           If unsure, say Y.
 708
 709 if PCI
 710
 711 config PCI_NR_FUNCTIONS
 712         int "Maximum number of PCI functions (1-4096)"
 713         range 1 4096
 714         default "512"
 715         help
 716           This allows you to specify the maximum number of PCI functions which
 717           this kernel will support.
 718
 719 endif # PCI
 720
 721 config HAS_IOMEM
 722         def_bool PCI
 723
 724 config CHSC_SCH
 725         def_tristate m
 726         prompt "Support for CHSC subchannels"
 727         help
 728           This driver allows usage of CHSC subchannels. A CHSC subchannel
 729           is usually present on LPAR only.
 730           The driver creates a device /dev/chsc, which may be used to
 731           obtain I/O configuration information about the machine and
 732           to issue asynchronous chsc commands (DANGEROUS).
 733           You will usually only want to use this interface on a special
 734           LPAR designated for system management.
 735
 736           To compile this driver as a module, choose M here: the
 737           module will be called chsc_sch.
 738
 739           If unsure, say N.
 740
 741 config SCM_BUS
 742         def_bool y
 743         prompt "SCM bus driver"
 744         help
 745           Bus driver for Storage Class Memory.
 746
 747 config EADM_SCH
 748         def_tristate m
 749         prompt "Support for EADM subchannels"
 750         depends on SCM_BUS
 751         help
 752           This driver allows usage of EADM subchannels. EADM subchannels act
 753           as a communication vehicle for SCM increments.
 754
 755           To compile this driver as a module, choose M here: the
 756           module will be called eadm_sch.
 757
 758 config VFIO_CCW
 759         def_tristate n
 760         prompt "Support for VFIO-CCW subchannels"
 761         depends on S390_CCW_IOMMU && VFIO_MDEV
 762         help
 763           This driver allows usage of I/O subchannels via VFIO-CCW.
 764
 765           To compile this driver as a module, choose M here: the
 766           module will be called vfio_ccw.
 767
 768 config VFIO_AP
 769         def_tristate n
 770         prompt "VFIO support for AP devices"
 771         depends on S390_AP_IOMMU && VFIO_MDEV_DEVICE && KVM
 772         depends on ZCRYPT
 773         help
 774                 This driver grants access to Adjunct Processor (AP) devices
 775                 via the VFIO mediated device interface.
 776
 777                 To compile this driver as a module, choose M here: the module
 778                 will be called vfio_ap.
 779
 780 endmenu
 781
 782 menu "Dump support"
 783
 784 config CRASH_DUMP
 785         bool "kernel crash dumps"
 786         select KEXEC
 787         help
 788           Generate crash dump after being started by kexec.
 789           Crash dump kernels are loaded in the main kernel with kexec-tools
 790           into a specially reserved region and then later executed after
 791           a crash by kdump/kexec.
 792           Refer to <file:Documentation/s390/zfcpdump.rst> for more details on this.
 793           This option also enables s390 zfcpdump.
 794           See also <file:Documentation/s390/zfcpdump.rst>
 795
 796 endmenu
 797
 798 config CCW
 799         def_bool y
 800
 801 config HAVE_PNETID
 802         tristate
 803         default (SMC || CCWGROUP)
 804
 805 menu "Virtualization"
 806
 807 config PROTECTED_VIRTUALIZATION_GUEST
 808         def_bool n
 809         prompt "Protected virtualization guest support"
 810         select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
 811         help
 812           Select this option, if you want to be able to run this
 813           kernel as a protected virtualization KVM guest.
 814           Protected virtualization capable machines have a mini hypervisor
 815           located at machine level (an ultravisor). With help of the
 816           Ultravisor, KVM will be able to run "protected" VMs, special
 817           VMs whose memory and management data are unavailable to KVM.
 818
 819 config PFAULT
 820         def_bool y
 821         prompt "Pseudo page fault support"
 822         help
 823           Select this option, if you want to use PFAULT pseudo page fault
 824           handling under VM. If running native or in LPAR, this option
 825           has no effect. If your VM does not support PFAULT, PAGEEX
 826           pseudo page fault handling will be used.
 827           Note that VM 4.2 supports PFAULT but has a bug in its
 828           implementation that causes some problems.
 829           Everybody who wants to run Linux under VM != VM4.2 should select
 830           this option.
 831
 832 config CMM
 833         def_tristate n
 834         prompt "Cooperative memory management"
 835         help
 836           Select this option, if you want to enable the kernel interface
 837           to reduce the memory size of the system. This is accomplished
 838           by allocating pages of memory and put them "on hold". This only
 839           makes sense for a system running under VM where the unused pages
 840           will be reused by VM for other guest systems. The interface
 841           allows an external monitor to balance memory of many systems.
 842           Everybody who wants to run Linux under VM should select this
 843           option.
 844
 845 config CMM_IUCV
 846         def_bool y
 847         prompt "IUCV special message interface to cooperative memory management"
 848         depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
 849         help
 850           Select this option to enable the special message interface to
 851           the cooperative memory management.
 852
 853 config APPLDATA_BASE
 854         def_bool n
 855         prompt "Linux - VM Monitor Stream, base infrastructure"
 856         depends on PROC_FS
 857         help
 858           This provides a kernel interface for creating and updating z/VM APPLDATA
 859           monitor records. The monitor records are updated at certain time
 860           intervals, once the timer is started.
 861           Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
 862           i.e. enables or disables monitoring on the Linux side.
 863           A custom interval value (in seconds) can be written to
 864           /proc/appldata/interval.
 865
 866           Defaults are 60 seconds interval and timer off.
 867           The /proc entries can also be read from, showing the current settings.
 868
 869 config APPLDATA_MEM
 870         def_tristate m
 871         prompt "Monitor memory management statistics"
 872         depends on APPLDATA_BASE && VM_EVENT_COUNTERS
 873         help
 874           This provides memory management related data to the Linux - VM Monitor
 875           Stream, like paging/swapping rate, memory utilisation, etc.
 876           Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
 877           APPLDATA monitor record, i.e. enables or disables monitoring this record
 878           on the z/VM side.
 879
 880           Default is disabled.
 881           The /proc entry can also be read from, showing the current settings.
 882
 883           This can also be compiled as a module, which will be called
 884           appldata_mem.o.
 885
 886 config APPLDATA_OS
 887         def_tristate m
 888         prompt "Monitor OS statistics"
 889         depends on APPLDATA_BASE
 890         help
 891           This provides OS related data to the Linux - VM Monitor Stream, like
 892           CPU utilisation, etc.
 893           Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
 894           APPLDATA monitor record, i.e. enables or disables monitoring this record
 895           on the z/VM side.
 896
 897           Default is disabled.
 898           This can also be compiled as a module, which will be called
 899           appldata_os.o.
 900
 901 config APPLDATA_NET_SUM
 902         def_tristate m
 903         prompt "Monitor overall network statistics"
 904         depends on APPLDATA_BASE && NET
 905         help
 906           This provides network related data to the Linux - VM Monitor Stream,
 907           currently there is only a total sum of network I/O statistics, no
 908           per-interface data.
 909           Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
 910           APPLDATA monitor record, i.e. enables or disables monitoring this record
 911           on the z/VM side.
 912
 913           Default is disabled.
 914           This can also be compiled as a module, which will be called
 915           appldata_net_sum.o.
 916
 917 config S390_HYPFS_FS
 918         def_bool y
 919         prompt "s390 hypervisor file system support"
 920         select SYS_HYPERVISOR
 921         help
 922           This is a virtual file system intended to provide accounting
 923           information in an s390 hypervisor environment.
 924
 925 source "arch/s390/kvm/Kconfig"
 926
 927 config S390_GUEST
 928         def_bool y
 929         prompt "s390 support for virtio devices"
 930         select TTY
 931         select VIRTUALIZATION
 932         select VIRTIO
 933         help
 934           Enabling this option adds support for virtio based paravirtual device
 935           drivers on s390.
 936
 937           Select this option if you want to run the kernel as a guest under
 938           the KVM hypervisor.
 939
 940 endmenu
 941
 942 menu "Selftests"
 943
 944 config S390_UNWIND_SELFTEST
 945         def_tristate n
 946         prompt "Test unwind functions"
 947         help
 948           This option enables s390 specific stack unwinder testing kernel
 949           module. This option is not useful for distributions or general
 950           kernels, but only for kernel developers working on architecture code.
 951
 952           Say N if you are unsure.
 953
 954 endmenu