arch/s390/Kconfig

   1 #
   2 # For a description of the syntax of this configuration file,
   3 # see Documentation/kbuild/kconfig-language.txt.
   4 #
   5
   6 config MMU
   7         bool
   8         default y
   9
  10 config ZONE_DMA
  11         def_bool y
  12         depends on 64BIT
  13
  14 config LOCKDEP_SUPPORT
  15         bool
  16         default y
  17
  18 config STACKTRACE_SUPPORT
  19         bool
  20         default y
  21
  22 config RWSEM_GENERIC_SPINLOCK
  23         bool
  24
  25 config RWSEM_XCHGADD_ALGORITHM
  26         bool
  27         default y
  28
  29 config ARCH_HAS_ILOG2_U32
  30         bool
  31         default n
  32
  33 config ARCH_HAS_ILOG2_U64
  34         bool
  35         default n
  36
  37 config GENERIC_HWEIGHT
  38         bool
  39         default y
  40
  41 config GENERIC_TIME
  42         def_bool y
  43
  44 config NO_IOMEM
  45         def_bool y
  46
  47 mainmenu "Linux Kernel Configuration"
  48
  49 config S390
  50         bool
  51         default y
  52
  53 source "init/Kconfig"
  54
  55 menu "Base setup"
  56
  57 comment "Processor type and features"
  58
  59 config 64BIT
  60         bool "64 bit kernel"
  61         help
  62           Select this option if you have a 64 bit IBM zSeries machine
  63           and want to use the 64 bit addressing mode.
  64
  65 config 32BIT
  66         bool
  67         default y if !64BIT
  68
  69 config SMP
  70         bool "Symmetric multi-processing support"
  71         ---help---
  72           This enables support for systems with more than one CPU. If you have
  73           a system with only one CPU, like most personal computers, say N. If
  74           you have a system with more than one CPU, say Y.
  75
  76           If you say N here, the kernel will run on single and multiprocessor
  77           machines, but will use only one CPU of a multiprocessor machine. If
  78           you say Y here, the kernel will run on many, but not all,
  79           singleprocessor machines. On a singleprocessor machine, the kernel
  80           will run faster if you say N here.
  81
  82           See also the <file:Documentation/smp.txt> and the SMP-HOWTO
  83           available at <http://www.tldp.org/docs.html#howto>.
  84
  85           Even if you don't know what to do here, say Y.
  86
  87 config NR_CPUS
  88         int "Maximum number of CPUs (2-64)"
  89         range 2 64
  90         depends on SMP
  91         default "32"
  92         help
  93           This allows you to specify the maximum number of CPUs which this
  94           kernel will support.  The maximum supported value is 64 and the
  95           minimum value which makes sense is 2.
  96
  97           This is purely to save memory - each supported CPU adds
  98           approximately sixteen kilobytes to the kernel image.
  99
 100 config HOTPLUG_CPU
 101         bool "Support for hot-pluggable CPUs"
 102         depends on SMP
 103         select HOTPLUG
 104         default n
 105         help
 106           Say Y here to be able to turn CPUs off and on. CPUs
 107           can be controlled through /sys/devices/system/cpu/cpu#.
 108           Say N if you want to disable CPU hotplug.
 109
 110 config DEFAULT_MIGRATION_COST
 111         int
 112         default "1000000"
 113
 114 config MATHEMU
 115         bool "IEEE FPU emulation"
 116         depends on MARCH_G5
 117         help
 118           This option is required for IEEE compliant floating point arithmetic
 119           on older S/390 machines. Say Y unless you know your machine doesn't
 120           need this.
 121
 122 config COMPAT
 123         bool "Kernel support for 31 bit emulation"
 124         depends on 64BIT
 125         help
 126           Select this option if you want to enable your system kernel to
 127           handle system-calls from ELF binaries for 31 bit ESA.  This option
 128           (and some other stuff like libraries and such) is needed for
 129           executing 31 bit applications.  It is safe to say "Y".
 130
 131 config SYSVIPC_COMPAT
 132         bool
 133         depends on COMPAT && SYSVIPC
 134         default y
 135
 136 config AUDIT_ARCH
 137         bool
 138         default y
 139
 140 config S390_SWITCH_AMODE
 141         bool "Switch kernel/user addressing modes"
 142         help
 143           This option allows to switch the addressing modes of kernel and user
 144           space. The kernel parameter switch_amode=on will enable this feature,
 145           default is disabled. Enabling this (via kernel parameter) on machines
 146           earlier than IBM System z9-109 EC/BC will reduce system performance.
 147
 148           Note that this option will also be selected by selecting the execute
 149           protection option below. Enabling the execute protection via the
 150           noexec kernel parameter will also switch the addressing modes,
 151           independent of the switch_amode kernel parameter.
 152
 153
 154 config S390_EXEC_PROTECT
 155         bool "Data execute protection"
 156         select S390_SWITCH_AMODE
 157         help
 158           This option allows to enable a buffer overflow protection for user
 159           space programs and it also selects the addressing mode option above.
 160           The kernel parameter noexec=on will enable this feature and also
 161           switch the addressing modes, default is disabled. Enabling this (via
 162           kernel parameter) on machines earlier than IBM System z9-109 EC/BC
 163           will reduce system performance.
 164
 165 comment "Code generation options"
 166
 167 choice
 168         prompt "Processor type"
 169         default MARCH_G5
 170
 171 config MARCH_G5
 172         bool "S/390 model G5 and G6"
 173         depends on !64BIT
 174         help
 175           Select this to build a 31 bit kernel that works
 176           on all S/390 and zSeries machines.
 177
 178 config MARCH_Z900
 179         bool "IBM eServer zSeries model z800 and z900"
 180         help
 181           Select this to optimize for zSeries machines. This
 182           will enable some optimizations that are not available
 183           on older 31 bit only CPUs.
 184
 185 config MARCH_Z990
 186         bool "IBM eServer zSeries model z890 and z990"
 187         help
 188           Select this enable optimizations for model z890/z990.
 189           This will be slightly faster but does not work on
 190           older machines such as the z900.
 191
 192 config MARCH_Z9_109
 193         bool "IBM System z9"
 194         help
 195           Select this to enable optimizations for IBM System z9-109, IBM
 196           System z9 Enterprise Class (z9 EC), and IBM System z9 Business
 197           Class (z9 BC). The kernel will be slightly faster but will not
 198           work on older machines such as the z990, z890, z900, and z800.
 199
 200 endchoice
 201
 202 config PACK_STACK
 203         bool "Pack kernel stack"
 204         help
 205           This option enables the compiler option -mkernel-backchain if it
 206           is available. If the option is available the compiler supports
 207           the new stack layout which dramatically reduces the minimum stack
 208           frame size. With an old compiler a non-leaf function needs a
 209           minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
 210           -mkernel-backchain the minimum size drops to 16 byte on 31 bit
 211           and 24 byte on 64 bit.
 212
 213           Say Y if you are unsure.
 214
 215 config SMALL_STACK
 216         bool "Use 4kb/8kb for kernel stack instead of 8kb/16kb"
 217         depends on PACK_STACK && !LOCKDEP
 218         help
 219           If you say Y here and the compiler supports the -mkernel-backchain
 220           option the kernel will use a smaller kernel stack size. For 31 bit
 221           the reduced size is 4kb instead of 8kb and for 64 bit it is 8kb
 222           instead of 16kb. This allows to run more thread on a system and
 223           reduces the pressure on the memory management for higher order
 224           page allocations.
 225
 226           Say N if you are unsure.
 227
 228
 229 config CHECK_STACK
 230         bool "Detect kernel stack overflow"
 231         help
 232           This option enables the compiler option -mstack-guard and
 233           -mstack-size if they are available. If the compiler supports them
 234           it will emit additional code to each function prolog to trigger
 235           an illegal operation if the kernel stack is about to overflow.
 236
 237           Say N if you are unsure.
 238
 239 config STACK_GUARD
 240         int "Size of the guard area (128-1024)"
 241         range 128 1024
 242         depends on CHECK_STACK
 243         default "256"
 244         help
 245           This allows you to specify the size of the guard area at the lower
 246           end of the kernel stack. If the kernel stack points into the guard
 247           area on function entry an illegal operation is triggered. The size
 248           needs to be a power of 2. Please keep in mind that the size of an
 249           interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
 250           The minimum size for the stack guard should be 256 for 31 bit and
 251           512 for 64 bit.
 252
 253 config WARN_STACK
 254         bool "Emit compiler warnings for function with broken stack usage"
 255         help
 256           This option enables the compiler options -mwarn-framesize and
 257           -mwarn-dynamicstack. If the compiler supports these options it
 258           will generate warnings for function which either use alloca or
 259           create a stack frame bigger then CONFIG_WARN_STACK_SIZE.
 260
 261           Say N if you are unsure.
 262
 263 config WARN_STACK_SIZE
 264         int "Maximum frame size considered safe (128-2048)"
 265         range 128 2048
 266         depends on WARN_STACK
 267         default "256"
 268         help
 269           This allows you to specify the maximum frame size a function may
 270           have without the compiler complaining about it.
 271
 272 config ARCH_POPULATES_NODE_MAP
 273         def_bool y
 274
 275 source "mm/Kconfig"
 276
 277 config HOLES_IN_ZONE
 278         def_bool y
 279
 280 comment "I/O subsystem configuration"
 281
 282 config MACHCHK_WARNING
 283         bool "Process warning machine checks"
 284         help
 285           Select this option if you want the machine check handler on IBM S/390 or
 286           zSeries to process warning machine checks (e.g. on power failures).
 287           If unsure, say "Y".
 288
 289 config QDIO
 290         tristate "QDIO support"
 291         ---help---
 292           This driver provides the Queued Direct I/O base support for
 293           IBM mainframes.
 294
 295           For details please refer to the documentation provided by IBM at
 296           <http://www10.software.ibm.com/developerworks/opensource/linux390>
 297
 298           To compile this driver as a module, choose M here: the
 299           module will be called qdio.
 300
 301           If unsure, say Y.
 302
 303 config QDIO_DEBUG
 304         bool "Extended debugging information"
 305         depends on QDIO
 306         help
 307           Say Y here to get extended debugging output in
 308             /sys/kernel/debug/s390dbf/qdio...
 309           Warning: this option reduces the performance of the QDIO module.
 310
 311           If unsure, say N.
 312
 313 comment "Misc"
 314
 315 config PREEMPT
 316         bool "Preemptible Kernel"
 317         help
 318           This option reduces the latency of the kernel when reacting to
 319           real-time or interactive events by allowing a low priority process to
 320           be preempted even if it is in kernel mode executing a system call.
 321           This allows applications to run more reliably even when the system is
 322           under load.
 323
 324           Say N if you are unsure.
 325
 326 config IPL
 327         bool "Builtin IPL record support"
 328         help
 329           If you want to use the produced kernel to IPL directly from a
 330           device, you have to merge a bootsector specific to the device
 331           into the first bytes of the kernel. You will have to select the
 332           IPL device.
 333
 334 choice
 335         prompt "IPL method generated into head.S"
 336         depends on IPL
 337         default IPL_TAPE
 338         help
 339           Select "tape" if you want to IPL the image from a Tape.
 340
 341           Select "vm_reader" if you are running under VM/ESA and want
 342           to IPL the image from the emulated card reader.
 343
 344 config IPL_TAPE
 345         bool "tape"
 346
 347 config IPL_VM
 348         bool "vm_reader"
 349
 350 endchoice
 351
 352 source "fs/Kconfig.binfmt"
 353
 354 config PROCESS_DEBUG
 355         bool "Show crashed user process info"
 356         help
 357           Say Y to print all process fault locations to the console.  This is
 358           a debugging option; you probably do not want to set it unless you
 359           are an S390 port maintainer.
 360
 361 config PFAULT
 362         bool "Pseudo page fault support"
 363         help
 364           Select this option, if you want to use PFAULT pseudo page fault
 365           handling under VM. If running native or in LPAR, this option
 366           has no effect. If your VM does not support PFAULT, PAGEEX
 367           pseudo page fault handling will be used.
 368           Note that VM 4.2 supports PFAULT but has a bug in its
 369           implementation that causes some problems.
 370           Everybody who wants to run Linux under VM != VM4.2 should select
 371           this option.
 372
 373 config SHARED_KERNEL
 374         bool "VM shared kernel support"
 375         help
 376           Select this option, if you want to share the text segment of the
 377           Linux kernel between different VM guests. This reduces memory
 378           usage with lots of guests but greatly increases kernel size.
 379           Also if a kernel was IPL'ed from a shared segment the kexec system
 380           call will not work.
 381           You should only select this option if you know what you are
 382           doing and want to exploit this feature.
 383
 384 config CMM
 385         tristate "Cooperative memory management"
 386         help
 387           Select this option, if you want to enable the kernel interface
 388           to reduce the memory size of the system. This is accomplished
 389           by allocating pages of memory and put them "on hold". This only
 390           makes sense for a system running under VM where the unused pages
 391           will be reused by VM for other guest systems. The interface
 392           allows an external monitor to balance memory of many systems.
 393           Everybody who wants to run Linux under VM should select this
 394           option.
 395
 396 config CMM_PROC
 397         bool "/proc interface to cooperative memory management"
 398         depends on CMM
 399         help
 400           Select this option to enable the /proc interface to the
 401           cooperative memory management.
 402
 403 config CMM_IUCV
 404         bool "IUCV special message interface to cooperative memory management"
 405         depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
 406         help
 407           Select this option to enable the special message interface to
 408           the cooperative memory management.
 409
 410 config VIRT_TIMER
 411         bool "Virtual CPU timer support"
 412         help
 413           This provides a kernel interface for virtual CPU timers.
 414           Default is disabled.
 415
 416 config VIRT_CPU_ACCOUNTING
 417         bool "Base user process accounting on virtual cpu timer"
 418         depends on VIRT_TIMER
 419         help
 420           Select this option to use CPU timer deltas to do user
 421           process accounting.
 422
 423 config APPLDATA_BASE
 424         bool "Linux - VM Monitor Stream, base infrastructure"
 425         depends on PROC_FS && VIRT_TIMER=y
 426         help
 427           This provides a kernel interface for creating and updating z/VM APPLDATA
 428           monitor records. The monitor records are updated at certain time
 429           intervals, once the timer is started.
 430           Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
 431           i.e. enables or disables monitoring on the Linux side.
 432           A custom interval value (in seconds) can be written to
 433           /proc/appldata/interval.
 434
 435           Defaults are 60 seconds interval and timer off.
 436           The /proc entries can also be read from, showing the current settings.
 437
 438 config APPLDATA_MEM
 439         tristate "Monitor memory management statistics"
 440         depends on APPLDATA_BASE && VM_EVENT_COUNTERS
 441         help
 442           This provides memory management related data to the Linux - VM Monitor
 443           Stream, like paging/swapping rate, memory utilisation, etc.
 444           Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
 445           APPLDATA monitor record, i.e. enables or disables monitoring this record
 446           on the z/VM side.
 447
 448           Default is disabled.
 449           The /proc entry can also be read from, showing the current settings.
 450
 451           This can also be compiled as a module, which will be called
 452           appldata_mem.o.
 453
 454 config APPLDATA_OS
 455         tristate "Monitor OS statistics"
 456         depends on APPLDATA_BASE
 457         help
 458           This provides OS related data to the Linux - VM Monitor Stream, like
 459           CPU utilisation, etc.
 460           Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
 461           APPLDATA monitor record, i.e. enables or disables monitoring this record
 462           on the z/VM side.
 463
 464           Default is disabled.
 465           This can also be compiled as a module, which will be called
 466           appldata_os.o.
 467
 468 config APPLDATA_NET_SUM
 469         tristate "Monitor overall network statistics"
 470         depends on APPLDATA_BASE
 471         help
 472           This provides network related data to the Linux - VM Monitor Stream,
 473           currently there is only a total sum of network I/O statistics, no
 474           per-interface data.
 475           Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
 476           APPLDATA monitor record, i.e. enables or disables monitoring this record
 477           on the z/VM side.
 478
 479           Default is disabled.
 480           This can also be compiled as a module, which will be called
 481           appldata_net_sum.o.
 482
 483 config NO_IDLE_HZ
 484         bool "No HZ timer ticks in idle"
 485         help
 486           Switches the regular HZ timer off when the system is going idle.
 487           This helps z/VM to detect that the Linux system is idle. VM can
 488           then "swap-out" this guest which reduces memory usage. It also
 489           reduces the overhead of idle systems.
 490
 491           The HZ timer can be switched on/off via /proc/sys/kernel/hz_timer.
 492           hz_timer=0 means HZ timer is disabled. hz_timer=1 means HZ
 493           timer is active.
 494
 495 config NO_IDLE_HZ_INIT
 496         bool "HZ timer in idle off by default"
 497         depends on NO_IDLE_HZ
 498         help
 499           The HZ timer is switched off in idle by default. That means the
 500           HZ timer is already disabled at boot time.
 501
 502 config S390_HYPFS_FS
 503         bool "s390 hypervisor file system support"
 504         select SYS_HYPERVISOR
 505         default y
 506         help
 507           This is a virtual file system intended to provide accounting
 508           information in an s390 hypervisor environment.
 509
 510 config KEXEC
 511         bool "kexec system call"
 512         help
 513           kexec is a system call that implements the ability to shutdown your
 514           current kernel, and to start another kernel.  It is like a reboot
 515           but is independent of hardware/microcode support.
 516
 517 endmenu
 518
 519 source "net/Kconfig"
 520
 521 config PCMCIA
 522         bool
 523         default n
 524
 525 source "drivers/base/Kconfig"
 526
 527 source "drivers/connector/Kconfig"
 528
 529 source "drivers/scsi/Kconfig"
 530
 531 source "drivers/s390/Kconfig"
 532
 533 source "drivers/net/Kconfig"
 534
 535 source "fs/Kconfig"
 536
 537 menu "Instrumentation Support"
 538
 539 source "arch/s390/oprofile/Kconfig"
 540
 541 config KPROBES
 542         bool "Kprobes (EXPERIMENTAL)"
 543         depends on EXPERIMENTAL && MODULES
 544         help
 545           Kprobes allows you to trap at almost any kernel address and
 546           execute a callback function.  register_kprobe() establishes
 547           a probepoint and specifies the callback.  Kprobes is useful
 548           for kernel debugging, non-intrusive instrumentation and testing.
 549           If in doubt, say "N".
 550
 551 endmenu
 552
 553 source "arch/s390/Kconfig.debug"
 554
 555 source "security/Kconfig"
 556
 557 source "crypto/Kconfig"
 558
 559 source "lib/Kconfig"