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