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 ZONE_DMA 11 def_bool y 12 depends on 64BIT 13 14config LOCKDEP_SUPPORT 15 bool 16 default y 17 18config STACKTRACE_SUPPORT 19 bool 20 default y 21 22config RWSEM_GENERIC_SPINLOCK 23 bool 24 25config RWSEM_XCHGADD_ALGORITHM 26 bool 27 default y 28 29config ARCH_HAS_ILOG2_U32 30 bool 31 default n 32 33config ARCH_HAS_ILOG2_U64 34 bool 35 default n 36 37config GENERIC_HWEIGHT 38 bool 39 default y 40 41config GENERIC_TIME 42 def_bool y 43 44config NO_IOMEM 45 def_bool y 46 47mainmenu "Linux Kernel Configuration" 48 49config S390 50 bool 51 default y 52 53source "init/Kconfig" 54 55menu "Base setup" 56 57comment "Processor type and features" 58 59config 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 65config 32BIT 66 bool 67 default y if !64BIT 68 69config 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 87config 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 100config 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 110config DEFAULT_MIGRATION_COST 111 int 112 default "1000000" 113 114config 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 122config 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 131config SYSVIPC_COMPAT 132 bool 133 depends on COMPAT && SYSVIPC 134 default y 135 136config AUDIT_ARCH 137 bool 138 default y 139 140config 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 154config 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 165comment "Code generation options" 166 167choice 168 prompt "Processor type" 169 default MARCH_G5 170 171config 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 178config 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 185config 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 192config 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 200endchoice 201 202config 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 215config 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 229config 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 239config 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 253config 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 263config 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 272config ARCH_POPULATES_NODE_MAP 273 def_bool y 274 275source "mm/Kconfig" 276 277config HOLES_IN_ZONE 278 def_bool y 279 280comment "I/O subsystem configuration" 281 282config 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 289config 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 303config 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 313comment "Misc" 314 315config 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 326config 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 334choice 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 344config IPL_TAPE 345 bool "tape" 346 347config IPL_VM 348 bool "vm_reader" 349 350endchoice 351 352source "fs/Kconfig.binfmt" 353 354config 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 361config 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 373config 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 384config 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 396config 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 403config 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 410config 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 416config 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 423config 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 438config 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 454config 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 468config 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 483config 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 495config 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 502config 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 510config 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 517endmenu 518 519source "net/Kconfig" 520 521config PCMCIA 522 bool 523 default n 524 525source "drivers/base/Kconfig" 526 527source "drivers/connector/Kconfig" 528 529source "drivers/scsi/Kconfig" 530 531source "drivers/s390/Kconfig" 532 533source "drivers/net/Kconfig" 534 535source "fs/Kconfig" 536 537menu "Instrumentation Support" 538 539source "arch/s390/oprofile/Kconfig" 540 541config 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 551endmenu 552 553source "arch/s390/Kconfig.debug" 554 555source "security/Kconfig" 556 557source "crypto/Kconfig" 558 559source "lib/Kconfig" 560