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 RWSEM_GENERIC_SPINLOCK 11 bool 12 13config RWSEM_XCHGADD_ALGORITHM 14 bool 15 default y 16 17config GENERIC_CALIBRATE_DELAY 18 bool 19 default y 20 21config GENERIC_BUST_SPINLOCK 22 bool 23 24mainmenu "Linux Kernel Configuration" 25 26config ARCH_S390 27 bool 28 default y 29 30config UID16 31 bool 32 default y 33 depends on ARCH_S390X = 'n' 34 35source "init/Kconfig" 36 37menu "Base setup" 38 39comment "Processor type and features" 40 41config ARCH_S390X 42 bool "64 bit kernel" 43 help 44 Select this option if you have a 64 bit IBM zSeries machine 45 and want to use the 64 bit addressing mode. 46 47config 64BIT 48 def_bool ARCH_S390X 49 50config ARCH_S390_31 51 bool 52 depends on ARCH_S390X = 'n' 53 default y 54 55config SMP 56 bool "Symmetric multi-processing support" 57 ---help--- 58 This enables support for systems with more than one CPU. If you have 59 a system with only one CPU, like most personal computers, say N. If 60 you have a system with more than one CPU, say Y. 61 62 If you say N here, the kernel will run on single and multiprocessor 63 machines, but will use only one CPU of a multiprocessor machine. If 64 you say Y here, the kernel will run on many, but not all, 65 singleprocessor machines. On a singleprocessor machine, the kernel 66 will run faster if you say N here. 67 68 See also the <file:Documentation/smp.txt> and the SMP-HOWTO 69 available at <http://www.tldp.org/docs.html#howto>. 70 71 Even if you don't know what to do here, say Y. 72 73config NR_CPUS 74 int "Maximum number of CPUs (2-64)" 75 range 2 64 76 depends on SMP 77 default "32" 78 help 79 This allows you to specify the maximum number of CPUs which this 80 kernel will support. The maximum supported value is 64 and the 81 minimum value which makes sense is 2. 82 83 This is purely to save memory - each supported CPU adds 84 approximately sixteen kilobytes to the kernel image. 85 86config HOTPLUG_CPU 87 bool "Support for hot-pluggable CPUs" 88 depends on SMP 89 select HOTPLUG 90 default n 91 help 92 Say Y here to be able to turn CPUs off and on. CPUs 93 can be controlled through /sys/devices/system/cpu/cpu#. 94 Say N if you want to disable CPU hotplug. 95 96config MATHEMU 97 bool "IEEE FPU emulation" 98 depends on MARCH_G5 99 help 100 This option is required for IEEE compliant floating point arithmetic 101 on older S/390 machines. Say Y unless you know your machine doesn't 102 need this. 103 104config S390_SUPPORT 105 bool "Kernel support for 31 bit emulation" 106 depends on ARCH_S390X 107 help 108 Select this option if you want to enable your system kernel to 109 handle system-calls from ELF binaries for 31 bit ESA. This option 110 (and some other stuff like libraries and such) is needed for 111 executing 31 bit applications. It is safe to say "Y". 112 113config COMPAT 114 bool 115 depends on S390_SUPPORT 116 default y 117 118config SYSVIPC_COMPAT 119 bool 120 depends on COMPAT && SYSVIPC 121 default y 122 123config BINFMT_ELF32 124 tristate "Kernel support for 31 bit ELF binaries" 125 depends on S390_SUPPORT 126 help 127 This allows you to run 32-bit Linux/ELF binaries on your zSeries 128 in 64 bit mode. Everybody wants this; say Y. 129 130comment "Code generation options" 131 132choice 133 prompt "Processor type" 134 default MARCH_G5 135 136config MARCH_G5 137 bool "S/390 model G5 and G6" 138 depends on ARCH_S390_31 139 help 140 Select this to build a 31 bit kernel that works 141 on all S/390 and zSeries machines. 142 143config MARCH_Z900 144 bool "IBM eServer zSeries model z800 and z900" 145 help 146 Select this to optimize for zSeries machines. This 147 will enable some optimizations that are not available 148 on older 31 bit only CPUs. 149 150config MARCH_Z990 151 bool "IBM eServer zSeries model z890 and z990" 152 help 153 Select this enable optimizations for model z890/z990. 154 This will be slightly faster but does not work on 155 older machines such as the z900. 156 157endchoice 158 159config PACK_STACK 160 bool "Pack kernel stack" 161 help 162 This option enables the compiler option -mkernel-backchain if it 163 is available. If the option is available the compiler supports 164 the new stack layout which dramatically reduces the minimum stack 165 frame size. With an old compiler a non-leaf function needs a 166 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With 167 -mkernel-backchain the minimum size drops to 16 byte on 31 bit 168 and 24 byte on 64 bit. 169 170 Say Y if you are unsure. 171 172config SMALL_STACK 173 bool "Use 4kb/8kb for kernel stack instead of 8kb/16kb" 174 depends on PACK_STACK 175 help 176 If you say Y here and the compiler supports the -mkernel-backchain 177 option the kernel will use a smaller kernel stack size. For 31 bit 178 the reduced size is 4kb instead of 8kb and for 64 bit it is 8kb 179 instead of 16kb. This allows to run more thread on a system and 180 reduces the pressure on the memory management for higher order 181 page allocations. 182 183 Say N if you are unsure. 184 185 186config CHECK_STACK 187 bool "Detect kernel stack overflow" 188 help 189 This option enables the compiler option -mstack-guard and 190 -mstack-size if they are available. If the compiler supports them 191 it will emit additional code to each function prolog to trigger 192 an illegal operation if the kernel stack is about to overflow. 193 194 Say N if you are unsure. 195 196config STACK_GUARD 197 int "Size of the guard area (128-1024)" 198 range 128 1024 199 depends on CHECK_STACK 200 default "256" 201 help 202 This allows you to specify the size of the guard area at the lower 203 end of the kernel stack. If the kernel stack points into the guard 204 area on function entry an illegal operation is triggered. The size 205 needs to be a power of 2. Please keep in mind that the size of an 206 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit. 207 The minimum size for the stack guard should be 256 for 31 bit and 208 512 for 64 bit. 209 210config WARN_STACK 211 bool "Emit compiler warnings for function with broken stack usage" 212 help 213 This option enables the compiler options -mwarn-framesize and 214 -mwarn-dynamicstack. If the compiler supports these options it 215 will generate warnings for function which either use alloca or 216 create a stack frame bigger then CONFIG_WARN_STACK_SIZE. 217 218 Say N if you are unsure. 219 220config WARN_STACK_SIZE 221 int "Maximum frame size considered safe (128-2048)" 222 range 128 2048 223 depends on WARN_STACK 224 default "256" 225 help 226 This allows you to specify the maximum frame size a function may 227 have without the compiler complaining about it. 228 229source "mm/Kconfig" 230 231comment "I/O subsystem configuration" 232 233config MACHCHK_WARNING 234 bool "Process warning machine checks" 235 help 236 Select this option if you want the machine check handler on IBM S/390 or 237 zSeries to process warning machine checks (e.g. on power failures). 238 If unsure, say "Y". 239 240config QDIO 241 tristate "QDIO support" 242 ---help--- 243 This driver provides the Queued Direct I/O base support for the 244 IBM S/390 (G5 and G6) and eServer zSeries (z800, z890, z900 and z990). 245 246 For details please refer to the documentation provided by IBM at 247 <http://www10.software.ibm.com/developerworks/opensource/linux390> 248 249 To compile this driver as a module, choose M here: the 250 module will be called qdio. 251 252 If unsure, say Y. 253 254config QDIO_PERF_STATS 255 bool "Performance statistics in /proc" 256 depends on QDIO 257 help 258 Say Y here to get performance statistics in /proc/qdio_perf 259 260 If unsure, say N. 261 262config QDIO_DEBUG 263 bool "Extended debugging information" 264 depends on QDIO 265 help 266 Say Y here to get extended debugging output in /proc/s390dbf/qdio... 267 Warning: this option reduces the performance of the QDIO module. 268 269 If unsure, say N. 270 271comment "Misc" 272 273config PREEMPT 274 bool "Preemptible Kernel" 275 help 276 This option reduces the latency of the kernel when reacting to 277 real-time or interactive events by allowing a low priority process to 278 be preempted even if it is in kernel mode executing a system call. 279 This allows applications to run more reliably even when the system is 280 under load. 281 282 Say N if you are unsure. 283 284config IPL 285 bool "Builtin IPL record support" 286 help 287 If you want to use the produced kernel to IPL directly from a 288 device, you have to merge a bootsector specific to the device 289 into the first bytes of the kernel. You will have to select the 290 IPL device. 291 292choice 293 prompt "IPL method generated into head.S" 294 depends on IPL 295 default IPL_TAPE 296 help 297 Select "tape" if you want to IPL the image from a Tape. 298 299 Select "vm_reader" if you are running under VM/ESA and want 300 to IPL the image from the emulated card reader. 301 302config IPL_TAPE 303 bool "tape" 304 305config IPL_VM 306 bool "vm_reader" 307 308endchoice 309 310source "fs/Kconfig.binfmt" 311 312config PROCESS_DEBUG 313 bool "Show crashed user process info" 314 help 315 Say Y to print all process fault locations to the console. This is 316 a debugging option; you probably do not want to set it unless you 317 are an S390 port maintainer. 318 319config PFAULT 320 bool "Pseudo page fault support" 321 help 322 Select this option, if you want to use PFAULT pseudo page fault 323 handling under VM. If running native or in LPAR, this option 324 has no effect. If your VM does not support PFAULT, PAGEEX 325 pseudo page fault handling will be used. 326 Note that VM 4.2 supports PFAULT but has a bug in its 327 implementation that causes some problems. 328 Everybody who wants to run Linux under VM != VM4.2 should select 329 this option. 330 331config SHARED_KERNEL 332 bool "VM shared kernel support" 333 help 334 Select this option, if you want to share the text segment of the 335 Linux kernel between different VM guests. This reduces memory 336 usage with lots of guests but greatly increases kernel size. 337 You should only select this option if you know what you are 338 doing and want to exploit this feature. 339 340config CMM 341 tristate "Cooperative memory management" 342 help 343 Select this option, if you want to enable the kernel interface 344 to reduce the memory size of the system. This is accomplished 345 by allocating pages of memory and put them "on hold". This only 346 makes sense for a system running under VM where the unused pages 347 will be reused by VM for other guest systems. The interface 348 allows an external monitor to balance memory of many systems. 349 Everybody who wants to run Linux under VM should select this 350 option. 351 352config CMM_PROC 353 bool "/proc interface to cooperative memory management" 354 depends on CMM 355 help 356 Select this option to enable the /proc interface to the 357 cooperative memory management. 358 359config CMM_IUCV 360 bool "IUCV special message interface to cooperative memory management" 361 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV) 362 help 363 Select this option to enable the special message interface to 364 the cooperative memory management. 365 366config VIRT_TIMER 367 bool "Virtual CPU timer support" 368 help 369 This provides a kernel interface for virtual CPU timers. 370 Default is disabled. 371 372config VIRT_CPU_ACCOUNTING 373 bool "Base user process accounting on virtual cpu timer" 374 depends on VIRT_TIMER 375 help 376 Select this option to use CPU timer deltas to do user 377 process accounting. 378 379config APPLDATA_BASE 380 bool "Linux - VM Monitor Stream, base infrastructure" 381 depends on PROC_FS && VIRT_TIMER=y 382 help 383 This provides a kernel interface for creating and updating z/VM APPLDATA 384 monitor records. The monitor records are updated at certain time 385 intervals, once the timer is started. 386 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer, 387 i.e. enables or disables monitoring on the Linux side. 388 A custom interval value (in seconds) can be written to 389 /proc/appldata/interval. 390 391 Defaults are 60 seconds interval and timer off. 392 The /proc entries can also be read from, showing the current settings. 393 394config APPLDATA_MEM 395 tristate "Monitor memory management statistics" 396 depends on APPLDATA_BASE 397 help 398 This provides memory management related data to the Linux - VM Monitor 399 Stream, like paging/swapping rate, memory utilisation, etc. 400 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM 401 APPLDATA monitor record, i.e. enables or disables monitoring this record 402 on the z/VM side. 403 404 Default is disabled. 405 The /proc entry can also be read from, showing the current settings. 406 407 This can also be compiled as a module, which will be called 408 appldata_mem.o. 409 410config APPLDATA_OS 411 tristate "Monitor OS statistics" 412 depends on APPLDATA_BASE 413 help 414 This provides OS related data to the Linux - VM Monitor Stream, like 415 CPU utilisation, etc. 416 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM 417 APPLDATA monitor record, i.e. enables or disables monitoring this record 418 on the z/VM side. 419 420 Default is disabled. 421 This can also be compiled as a module, which will be called 422 appldata_os.o. 423 424config APPLDATA_NET_SUM 425 tristate "Monitor overall network statistics" 426 depends on APPLDATA_BASE 427 help 428 This provides network related data to the Linux - VM Monitor Stream, 429 currently there is only a total sum of network I/O statistics, no 430 per-interface data. 431 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM 432 APPLDATA monitor record, i.e. enables or disables monitoring this record 433 on the z/VM side. 434 435 Default is disabled. 436 This can also be compiled as a module, which will be called 437 appldata_net_sum.o. 438 439config NO_IDLE_HZ 440 bool "No HZ timer ticks in idle" 441 help 442 Switches the regular HZ timer off when the system is going idle. 443 This helps z/VM to detect that the Linux system is idle. VM can 444 then "swap-out" this guest which reduces memory usage. It also 445 reduces the overhead of idle systems. 446 447 The HZ timer can be switched on/off via /proc/sys/kernel/hz_timer. 448 hz_timer=0 means HZ timer is disabled. hz_timer=1 means HZ 449 timer is active. 450 451config NO_IDLE_HZ_INIT 452 bool "HZ timer in idle off by default" 453 depends on NO_IDLE_HZ 454 help 455 The HZ timer is switched off in idle by default. That means the 456 HZ timer is already disabled at boot time. 457 458config KEXEC 459 bool "kexec system call (EXPERIMENTAL)" 460 depends on EXPERIMENTAL 461 help 462 kexec is a system call that implements the ability to shutdown your 463 current kernel, and to start another kernel. It is like a reboot 464 but is independent of hardware/microcode support. 465 466endmenu 467 468source "net/Kconfig" 469 470config PCMCIA 471 bool 472 default n 473 474source "drivers/base/Kconfig" 475 476source "drivers/scsi/Kconfig" 477 478source "drivers/s390/Kconfig" 479 480source "drivers/net/Kconfig" 481 482source "fs/Kconfig" 483 484source "arch/s390/oprofile/Kconfig" 485 486source "arch/s390/Kconfig.debug" 487 488source "security/Kconfig" 489 490source "crypto/Kconfig" 491 492source "lib/Kconfig" 493