2 # For a description of the syntax of this configuration file,
3 # see Documentation/kbuild/kconfig-language.txt.
10 config LOCKDEP_SUPPORT
14 config STACKTRACE_SUPPORT
18 config RWSEM_GENERIC_SPINLOCK
21 config RWSEM_XCHGADD_ALGORITHM
25 config GENERIC_HWEIGHT
29 config GENERIC_CALIBRATE_DELAY
36 mainmenu "Linux Kernel Configuration"
46 comment "Processor type and features"
51 Select this option if you have a 64 bit IBM zSeries machine
52 and want to use the 64 bit addressing mode.
59 bool "Symmetric multi-processing support"
61 This enables support for systems with more than one CPU. If you have
62 a system with only one CPU, like most personal computers, say N. If
63 you have a system with more than one CPU, say Y.
65 If you say N here, the kernel will run on single and multiprocessor
66 machines, but will use only one CPU of a multiprocessor machine. If
67 you say Y here, the kernel will run on many, but not all,
68 singleprocessor machines. On a singleprocessor machine, the kernel
69 will run faster if you say N here.
71 See also the <file:Documentation/smp.txt> and the SMP-HOWTO
72 available at <http://www.tldp.org/docs.html#howto>.
74 Even if you don't know what to do here, say Y.
77 int "Maximum number of CPUs (2-64)"
82 This allows you to specify the maximum number of CPUs which this
83 kernel will support. The maximum supported value is 64 and the
84 minimum value which makes sense is 2.
86 This is purely to save memory - each supported CPU adds
87 approximately sixteen kilobytes to the kernel image.
90 bool "Support for hot-pluggable CPUs"
95 Say Y here to be able to turn CPUs off and on. CPUs
96 can be controlled through /sys/devices/system/cpu/cpu#.
97 Say N if you want to disable CPU hotplug.
99 config DEFAULT_MIGRATION_COST
104 bool "IEEE FPU emulation"
107 This option is required for IEEE compliant floating point arithmetic
108 on older S/390 machines. Say Y unless you know your machine doesn't
112 bool "Kernel support for 31 bit emulation"
115 Select this option if you want to enable your system kernel to
116 handle system-calls from ELF binaries for 31 bit ESA. This option
117 (and some other stuff like libraries and such) is needed for
118 executing 31 bit applications. It is safe to say "Y".
120 config SYSVIPC_COMPAT
122 depends on COMPAT && SYSVIPC
129 comment "Code generation options"
132 prompt "Processor type"
136 bool "S/390 model G5 and G6"
139 Select this to build a 31 bit kernel that works
140 on all S/390 and zSeries machines.
143 bool "IBM eServer zSeries model z800 and z900"
145 Select this to optimize for zSeries machines. This
146 will enable some optimizations that are not available
147 on older 31 bit only CPUs.
150 bool "IBM eServer zSeries model z890 and z990"
152 Select this enable optimizations for model z890/z990.
153 This will be slightly faster but does not work on
154 older machines such as the z900.
159 Select this to enable optimizations for IBM System z9-109, IBM
160 System z9 Enterprise Class (z9 EC), and IBM System z9 Business
161 Class (z9 BC). The kernel will be slightly faster but will not
162 work on older machines such as the z990, z890, z900, and z800.
167 bool "Pack kernel stack"
169 This option enables the compiler option -mkernel-backchain if it
170 is available. If the option is available the compiler supports
171 the new stack layout which dramatically reduces the minimum stack
172 frame size. With an old compiler a non-leaf function needs a
173 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
174 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
175 and 24 byte on 64 bit.
177 Say Y if you are unsure.
180 bool "Use 4kb/8kb for kernel stack instead of 8kb/16kb"
181 depends on PACK_STACK && !LOCKDEP
183 If you say Y here and the compiler supports the -mkernel-backchain
184 option the kernel will use a smaller kernel stack size. For 31 bit
185 the reduced size is 4kb instead of 8kb and for 64 bit it is 8kb
186 instead of 16kb. This allows to run more thread on a system and
187 reduces the pressure on the memory management for higher order
190 Say N if you are unsure.
194 bool "Detect kernel stack overflow"
196 This option enables the compiler option -mstack-guard and
197 -mstack-size if they are available. If the compiler supports them
198 it will emit additional code to each function prolog to trigger
199 an illegal operation if the kernel stack is about to overflow.
201 Say N if you are unsure.
204 int "Size of the guard area (128-1024)"
206 depends on CHECK_STACK
209 This allows you to specify the size of the guard area at the lower
210 end of the kernel stack. If the kernel stack points into the guard
211 area on function entry an illegal operation is triggered. The size
212 needs to be a power of 2. Please keep in mind that the size of an
213 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
214 The minimum size for the stack guard should be 256 for 31 bit and
218 bool "Emit compiler warnings for function with broken stack usage"
220 This option enables the compiler options -mwarn-framesize and
221 -mwarn-dynamicstack. If the compiler supports these options it
222 will generate warnings for function which either use alloca or
223 create a stack frame bigger then CONFIG_WARN_STACK_SIZE.
225 Say N if you are unsure.
227 config WARN_STACK_SIZE
228 int "Maximum frame size considered safe (128-2048)"
230 depends on WARN_STACK
233 This allows you to specify the maximum frame size a function may
234 have without the compiler complaining about it.
236 config ARCH_POPULATES_NODE_MAP
244 comment "I/O subsystem configuration"
246 config MACHCHK_WARNING
247 bool "Process warning machine checks"
249 Select this option if you want the machine check handler on IBM S/390 or
250 zSeries to process warning machine checks (e.g. on power failures).
254 tristate "QDIO support"
256 This driver provides the Queued Direct I/O base support for
259 For details please refer to the documentation provided by IBM at
260 <http://www10.software.ibm.com/developerworks/opensource/linux390>
262 To compile this driver as a module, choose M here: the
263 module will be called qdio.
268 bool "Extended debugging information"
271 Say Y here to get extended debugging output in
272 /sys/kernel/debug/s390dbf/qdio...
273 Warning: this option reduces the performance of the QDIO module.
280 bool "Preemptible Kernel"
282 This option reduces the latency of the kernel when reacting to
283 real-time or interactive events by allowing a low priority process to
284 be preempted even if it is in kernel mode executing a system call.
285 This allows applications to run more reliably even when the system is
288 Say N if you are unsure.
291 bool "Builtin IPL record support"
293 If you want to use the produced kernel to IPL directly from a
294 device, you have to merge a bootsector specific to the device
295 into the first bytes of the kernel. You will have to select the
299 prompt "IPL method generated into head.S"
303 Select "tape" if you want to IPL the image from a Tape.
305 Select "vm_reader" if you are running under VM/ESA and want
306 to IPL the image from the emulated card reader.
316 source "fs/Kconfig.binfmt"
319 bool "Show crashed user process info"
321 Say Y to print all process fault locations to the console. This is
322 a debugging option; you probably do not want to set it unless you
323 are an S390 port maintainer.
326 bool "Pseudo page fault support"
328 Select this option, if you want to use PFAULT pseudo page fault
329 handling under VM. If running native or in LPAR, this option
330 has no effect. If your VM does not support PFAULT, PAGEEX
331 pseudo page fault handling will be used.
332 Note that VM 4.2 supports PFAULT but has a bug in its
333 implementation that causes some problems.
334 Everybody who wants to run Linux under VM != VM4.2 should select
338 bool "VM shared kernel support"
340 Select this option, if you want to share the text segment of the
341 Linux kernel between different VM guests. This reduces memory
342 usage with lots of guests but greatly increases kernel size.
343 You should only select this option if you know what you are
344 doing and want to exploit this feature.
347 tristate "Cooperative memory management"
349 Select this option, if you want to enable the kernel interface
350 to reduce the memory size of the system. This is accomplished
351 by allocating pages of memory and put them "on hold". This only
352 makes sense for a system running under VM where the unused pages
353 will be reused by VM for other guest systems. The interface
354 allows an external monitor to balance memory of many systems.
355 Everybody who wants to run Linux under VM should select this
359 bool "/proc interface to cooperative memory management"
362 Select this option to enable the /proc interface to the
363 cooperative memory management.
366 bool "IUCV special message interface to cooperative memory management"
367 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
369 Select this option to enable the special message interface to
370 the cooperative memory management.
373 bool "Virtual CPU timer support"
375 This provides a kernel interface for virtual CPU timers.
378 config VIRT_CPU_ACCOUNTING
379 bool "Base user process accounting on virtual cpu timer"
380 depends on VIRT_TIMER
382 Select this option to use CPU timer deltas to do user
386 bool "Linux - VM Monitor Stream, base infrastructure"
387 depends on PROC_FS && VIRT_TIMER=y
389 This provides a kernel interface for creating and updating z/VM APPLDATA
390 monitor records. The monitor records are updated at certain time
391 intervals, once the timer is started.
392 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
393 i.e. enables or disables monitoring on the Linux side.
394 A custom interval value (in seconds) can be written to
395 /proc/appldata/interval.
397 Defaults are 60 seconds interval and timer off.
398 The /proc entries can also be read from, showing the current settings.
401 tristate "Monitor memory management statistics"
402 depends on APPLDATA_BASE
404 This provides memory management related data to the Linux - VM Monitor
405 Stream, like paging/swapping rate, memory utilisation, etc.
406 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
407 APPLDATA monitor record, i.e. enables or disables monitoring this record
411 The /proc entry can also be read from, showing the current settings.
413 This can also be compiled as a module, which will be called
417 tristate "Monitor OS statistics"
418 depends on APPLDATA_BASE
420 This provides OS related data to the Linux - VM Monitor Stream, like
421 CPU utilisation, etc.
422 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
423 APPLDATA monitor record, i.e. enables or disables monitoring this record
427 This can also be compiled as a module, which will be called
430 config APPLDATA_NET_SUM
431 tristate "Monitor overall network statistics"
432 depends on APPLDATA_BASE
434 This provides network related data to the Linux - VM Monitor Stream,
435 currently there is only a total sum of network I/O statistics, no
437 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
438 APPLDATA monitor record, i.e. enables or disables monitoring this record
442 This can also be compiled as a module, which will be called
446 bool "No HZ timer ticks in idle"
448 Switches the regular HZ timer off when the system is going idle.
449 This helps z/VM to detect that the Linux system is idle. VM can
450 then "swap-out" this guest which reduces memory usage. It also
451 reduces the overhead of idle systems.
453 The HZ timer can be switched on/off via /proc/sys/kernel/hz_timer.
454 hz_timer=0 means HZ timer is disabled. hz_timer=1 means HZ
457 config NO_IDLE_HZ_INIT
458 bool "HZ timer in idle off by default"
459 depends on NO_IDLE_HZ
461 The HZ timer is switched off in idle by default. That means the
462 HZ timer is already disabled at boot time.
465 bool "s390 hypervisor file system support"
466 select SYS_HYPERVISOR
469 This is a virtual file system intended to provide accounting
470 information in an s390 hypervisor environment.
473 bool "kexec system call"
475 kexec is a system call that implements the ability to shutdown your
476 current kernel, and to start another kernel. It is like a reboot
477 but is independent of hardware/microcode support.
487 source "drivers/base/Kconfig"
489 source "drivers/connector/Kconfig"
491 source "drivers/scsi/Kconfig"
493 source "drivers/s390/Kconfig"
495 source "drivers/net/Kconfig"
499 menu "Instrumentation Support"
501 source "arch/s390/oprofile/Kconfig"
504 bool "Kprobes (EXPERIMENTAL)"
505 depends on EXPERIMENTAL && MODULES
507 Kprobes allows you to trap at almost any kernel address and
508 execute a callback function. register_kprobe() establishes
509 a probepoint and specifies the callback. Kprobes is useful
510 for kernel debugging, non-intrusive instrumentation and testing.
511 If in doubt, say "N".
515 source "arch/s390/Kconfig.debug"
517 source "security/Kconfig"
519 source "crypto/Kconfig"