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
33 config GENERIC_BUST_SPINLOCK
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 bool "Pack kernel stack"
161 This option enables the compiler option -mkernel-backchain if it
162 is available. If the option is available the compiler supports
163 the new stack layout which dramatically reduces the minimum stack
164 frame size. With an old compiler a non-leaf function needs a
165 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
166 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
167 and 24 byte on 64 bit.
169 Say Y if you are unsure.
172 bool "Use 4kb/8kb for kernel stack instead of 8kb/16kb"
173 depends on PACK_STACK
175 If you say Y here and the compiler supports the -mkernel-backchain
176 option the kernel will use a smaller kernel stack size. For 31 bit
177 the reduced size is 4kb instead of 8kb and for 64 bit it is 8kb
178 instead of 16kb. This allows to run more thread on a system and
179 reduces the pressure on the memory management for higher order
182 Say N if you are unsure.
186 bool "Detect kernel stack overflow"
188 This option enables the compiler option -mstack-guard and
189 -mstack-size if they are available. If the compiler supports them
190 it will emit additional code to each function prolog to trigger
191 an illegal operation if the kernel stack is about to overflow.
193 Say N if you are unsure.
196 int "Size of the guard area (128-1024)"
198 depends on CHECK_STACK
201 This allows you to specify the size of the guard area at the lower
202 end of the kernel stack. If the kernel stack points into the guard
203 area on function entry an illegal operation is triggered. The size
204 needs to be a power of 2. Please keep in mind that the size of an
205 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
206 The minimum size for the stack guard should be 256 for 31 bit and
210 bool "Emit compiler warnings for function with broken stack usage"
212 This option enables the compiler options -mwarn-framesize and
213 -mwarn-dynamicstack. If the compiler supports these options it
214 will generate warnings for function which either use alloca or
215 create a stack frame bigger then CONFIG_WARN_STACK_SIZE.
217 Say N if you are unsure.
219 config WARN_STACK_SIZE
220 int "Maximum frame size considered safe (128-2048)"
222 depends on WARN_STACK
225 This allows you to specify the maximum frame size a function may
226 have without the compiler complaining about it.
230 comment "I/O subsystem configuration"
232 config MACHCHK_WARNING
233 bool "Process warning machine checks"
235 Select this option if you want the machine check handler on IBM S/390 or
236 zSeries to process warning machine checks (e.g. on power failures).
240 tristate "QDIO support"
242 This driver provides the Queued Direct I/O base support for
245 For details please refer to the documentation provided by IBM at
246 <http://www10.software.ibm.com/developerworks/opensource/linux390>
248 To compile this driver as a module, choose M here: the
249 module will be called qdio.
253 config QDIO_PERF_STATS
254 bool "Performance statistics in /proc"
257 Say Y here to get performance statistics in /proc/qdio_perf
262 bool "Extended debugging information"
265 Say Y here to get extended debugging output in
266 /sys/kernel/debug/s390dbf/qdio...
267 Warning: this option reduces the performance of the QDIO module.
274 bool "Preemptible Kernel"
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
282 Say N if you are unsure.
285 bool "Builtin IPL record support"
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
293 prompt "IPL method generated into head.S"
297 Select "tape" if you want to IPL the image from a Tape.
299 Select "vm_reader" if you are running under VM/ESA and want
300 to IPL the image from the emulated card reader.
310 source "fs/Kconfig.binfmt"
313 bool "Show crashed user process info"
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.
320 bool "Pseudo page fault support"
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
332 bool "VM shared kernel support"
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.
341 tristate "Cooperative memory management"
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
353 bool "/proc interface to cooperative memory management"
356 Select this option to enable the /proc interface to the
357 cooperative memory management.
360 bool "IUCV special message interface to cooperative memory management"
361 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
363 Select this option to enable the special message interface to
364 the cooperative memory management.
367 bool "Virtual CPU timer support"
369 This provides a kernel interface for virtual CPU timers.
372 config VIRT_CPU_ACCOUNTING
373 bool "Base user process accounting on virtual cpu timer"
374 depends on VIRT_TIMER
376 Select this option to use CPU timer deltas to do user
380 bool "Linux - VM Monitor Stream, base infrastructure"
381 depends on PROC_FS && VIRT_TIMER=y
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.
391 Defaults are 60 seconds interval and timer off.
392 The /proc entries can also be read from, showing the current settings.
395 tristate "Monitor memory management statistics"
396 depends on APPLDATA_BASE
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
405 The /proc entry can also be read from, showing the current settings.
407 This can also be compiled as a module, which will be called
411 tristate "Monitor OS statistics"
412 depends on APPLDATA_BASE
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
421 This can also be compiled as a module, which will be called
424 config APPLDATA_NET_SUM
425 tristate "Monitor overall network statistics"
426 depends on APPLDATA_BASE
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
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
436 This can also be compiled as a module, which will be called
440 bool "No HZ timer ticks in idle"
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.
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
451 config NO_IDLE_HZ_INIT
452 bool "HZ timer in idle off by default"
453 depends on NO_IDLE_HZ
455 The HZ timer is switched off in idle by default. That means the
456 HZ timer is already disabled at boot time.
459 bool "s390 hypervisor file system support"
460 select SYS_HYPERVISOR
463 This is a virtual file system intended to provide accounting
464 information in an s390 hypervisor environment.
467 bool "kexec system call (EXPERIMENTAL)"
468 depends on EXPERIMENTAL
470 kexec is a system call that implements the ability to shutdown your
471 current kernel, and to start another kernel. It is like a reboot
472 but is independent of hardware/microcode support.
482 source "drivers/base/Kconfig"
484 source "drivers/connector/Kconfig"
486 source "drivers/scsi/Kconfig"
488 source "drivers/s390/Kconfig"
490 source "drivers/net/Kconfig"
494 source "arch/s390/oprofile/Kconfig"
496 source "arch/s390/Kconfig.debug"
498 source "kernel/vserver/Kconfig"
500 source "security/Kconfig"
502 source "crypto/Kconfig"