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