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 config GENERIC_BUST_SPINLOCK
39 mainmenu "Linux Kernel Configuration"
49 comment "Processor type and features"
54 Select this option if you have a 64 bit IBM zSeries machine
55 and want to use the 64 bit addressing mode.
62 bool "Symmetric multi-processing support"
64 This enables support for systems with more than one CPU. If you have
65 a system with only one CPU, like most personal computers, say N. If
66 you have a system with more than one CPU, say Y.
68 If you say N here, the kernel will run on single and multiprocessor
69 machines, but will use only one CPU of a multiprocessor machine. If
70 you say Y here, the kernel will run on many, but not all,
71 singleprocessor machines. On a singleprocessor machine, the kernel
72 will run faster if you say N here.
74 See also the <file:Documentation/smp.txt> and the SMP-HOWTO
75 available at <http://www.tldp.org/docs.html#howto>.
77 Even if you don't know what to do here, say Y.
80 int "Maximum number of CPUs (2-64)"
85 This allows you to specify the maximum number of CPUs which this
86 kernel will support. The maximum supported value is 64 and the
87 minimum value which makes sense is 2.
89 This is purely to save memory - each supported CPU adds
90 approximately sixteen kilobytes to the kernel image.
93 bool "Support for hot-pluggable CPUs"
98 Say Y here to be able to turn CPUs off and on. CPUs
99 can be controlled through /sys/devices/system/cpu/cpu#.
100 Say N if you want to disable CPU hotplug.
102 config DEFAULT_MIGRATION_COST
107 bool "IEEE FPU emulation"
110 This option is required for IEEE compliant floating point arithmetic
111 on older S/390 machines. Say Y unless you know your machine doesn't
115 bool "Kernel support for 31 bit emulation"
118 Select this option if you want to enable your system kernel to
119 handle system-calls from ELF binaries for 31 bit ESA. This option
120 (and some other stuff like libraries and such) is needed for
121 executing 31 bit applications. It is safe to say "Y".
123 config SYSVIPC_COMPAT
125 depends on COMPAT && SYSVIPC
132 comment "Code generation options"
135 prompt "Processor type"
139 bool "S/390 model G5 and G6"
142 Select this to build a 31 bit kernel that works
143 on all S/390 and zSeries machines.
146 bool "IBM eServer zSeries model z800 and z900"
148 Select this to optimize for zSeries machines. This
149 will enable some optimizations that are not available
150 on older 31 bit only CPUs.
153 bool "IBM eServer zSeries model z890 and z990"
155 Select this enable optimizations for model z890/z990.
156 This will be slightly faster but does not work on
157 older machines such as the z900.
162 Select this to enable optimizations for IBM System z9-109, IBM
163 System z9 Enterprise Class (z9 EC), and IBM System z9 Business
164 Class (z9 BC). The kernel will be slightly faster but will not
165 work on older machines such as the z990, z890, z900, and z800.
170 bool "Pack kernel stack"
172 This option enables the compiler option -mkernel-backchain if it
173 is available. If the option is available the compiler supports
174 the new stack layout which dramatically reduces the minimum stack
175 frame size. With an old compiler a non-leaf function needs a
176 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
177 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
178 and 24 byte on 64 bit.
180 Say Y if you are unsure.
183 bool "Use 4kb/8kb for kernel stack instead of 8kb/16kb"
184 depends on PACK_STACK
186 If you say Y here and the compiler supports the -mkernel-backchain
187 option the kernel will use a smaller kernel stack size. For 31 bit
188 the reduced size is 4kb instead of 8kb and for 64 bit it is 8kb
189 instead of 16kb. This allows to run more thread on a system and
190 reduces the pressure on the memory management for higher order
193 Say N if you are unsure.
197 bool "Detect kernel stack overflow"
199 This option enables the compiler option -mstack-guard and
200 -mstack-size if they are available. If the compiler supports them
201 it will emit additional code to each function prolog to trigger
202 an illegal operation if the kernel stack is about to overflow.
204 Say N if you are unsure.
207 int "Size of the guard area (128-1024)"
209 depends on CHECK_STACK
212 This allows you to specify the size of the guard area at the lower
213 end of the kernel stack. If the kernel stack points into the guard
214 area on function entry an illegal operation is triggered. The size
215 needs to be a power of 2. Please keep in mind that the size of an
216 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
217 The minimum size for the stack guard should be 256 for 31 bit and
221 bool "Emit compiler warnings for function with broken stack usage"
223 This option enables the compiler options -mwarn-framesize and
224 -mwarn-dynamicstack. If the compiler supports these options it
225 will generate warnings for function which either use alloca or
226 create a stack frame bigger then CONFIG_WARN_STACK_SIZE.
228 Say N if you are unsure.
230 config WARN_STACK_SIZE
231 int "Maximum frame size considered safe (128-2048)"
233 depends on WARN_STACK
236 This allows you to specify the maximum frame size a function may
237 have without the compiler complaining about it.
241 comment "I/O subsystem configuration"
243 config MACHCHK_WARNING
244 bool "Process warning machine checks"
246 Select this option if you want the machine check handler on IBM S/390 or
247 zSeries to process warning machine checks (e.g. on power failures).
251 tristate "QDIO support"
253 This driver provides the Queued Direct I/O base support for
256 For details please refer to the documentation provided by IBM at
257 <http://www10.software.ibm.com/developerworks/opensource/linux390>
259 To compile this driver as a module, choose M here: the
260 module will be called qdio.
264 config QDIO_PERF_STATS
265 bool "Performance statistics in /proc"
268 Say Y here to get performance statistics in /proc/qdio_perf
273 bool "Extended debugging information"
276 Say Y here to get extended debugging output in
277 /sys/kernel/debug/s390dbf/qdio...
278 Warning: this option reduces the performance of the QDIO module.
285 bool "Preemptible Kernel"
287 This option reduces the latency of the kernel when reacting to
288 real-time or interactive events by allowing a low priority process to
289 be preempted even if it is in kernel mode executing a system call.
290 This allows applications to run more reliably even when the system is
293 Say N if you are unsure.
296 bool "Builtin IPL record support"
298 If you want to use the produced kernel to IPL directly from a
299 device, you have to merge a bootsector specific to the device
300 into the first bytes of the kernel. You will have to select the
304 prompt "IPL method generated into head.S"
308 Select "tape" if you want to IPL the image from a Tape.
310 Select "vm_reader" if you are running under VM/ESA and want
311 to IPL the image from the emulated card reader.
321 source "fs/Kconfig.binfmt"
324 bool "Show crashed user process info"
326 Say Y to print all process fault locations to the console. This is
327 a debugging option; you probably do not want to set it unless you
328 are an S390 port maintainer.
331 bool "Pseudo page fault support"
333 Select this option, if you want to use PFAULT pseudo page fault
334 handling under VM. If running native or in LPAR, this option
335 has no effect. If your VM does not support PFAULT, PAGEEX
336 pseudo page fault handling will be used.
337 Note that VM 4.2 supports PFAULT but has a bug in its
338 implementation that causes some problems.
339 Everybody who wants to run Linux under VM != VM4.2 should select
343 bool "VM shared kernel support"
345 Select this option, if you want to share the text segment of the
346 Linux kernel between different VM guests. This reduces memory
347 usage with lots of guests but greatly increases kernel size.
348 You should only select this option if you know what you are
349 doing and want to exploit this feature.
352 tristate "Cooperative memory management"
354 Select this option, if you want to enable the kernel interface
355 to reduce the memory size of the system. This is accomplished
356 by allocating pages of memory and put them "on hold". This only
357 makes sense for a system running under VM where the unused pages
358 will be reused by VM for other guest systems. The interface
359 allows an external monitor to balance memory of many systems.
360 Everybody who wants to run Linux under VM should select this
364 bool "/proc interface to cooperative memory management"
367 Select this option to enable the /proc interface to the
368 cooperative memory management.
371 bool "IUCV special message interface to cooperative memory management"
372 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
374 Select this option to enable the special message interface to
375 the cooperative memory management.
378 bool "Virtual CPU timer support"
380 This provides a kernel interface for virtual CPU timers.
383 config VIRT_CPU_ACCOUNTING
384 bool "Base user process accounting on virtual cpu timer"
385 depends on VIRT_TIMER
387 Select this option to use CPU timer deltas to do user
391 bool "Linux - VM Monitor Stream, base infrastructure"
392 depends on PROC_FS && VIRT_TIMER=y
394 This provides a kernel interface for creating and updating z/VM APPLDATA
395 monitor records. The monitor records are updated at certain time
396 intervals, once the timer is started.
397 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
398 i.e. enables or disables monitoring on the Linux side.
399 A custom interval value (in seconds) can be written to
400 /proc/appldata/interval.
402 Defaults are 60 seconds interval and timer off.
403 The /proc entries can also be read from, showing the current settings.
406 tristate "Monitor memory management statistics"
407 depends on APPLDATA_BASE
409 This provides memory management related data to the Linux - VM Monitor
410 Stream, like paging/swapping rate, memory utilisation, etc.
411 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
412 APPLDATA monitor record, i.e. enables or disables monitoring this record
416 The /proc entry can also be read from, showing the current settings.
418 This can also be compiled as a module, which will be called
422 tristate "Monitor OS statistics"
423 depends on APPLDATA_BASE
425 This provides OS related data to the Linux - VM Monitor Stream, like
426 CPU utilisation, etc.
427 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
428 APPLDATA monitor record, i.e. enables or disables monitoring this record
432 This can also be compiled as a module, which will be called
435 config APPLDATA_NET_SUM
436 tristate "Monitor overall network statistics"
437 depends on APPLDATA_BASE
439 This provides network related data to the Linux - VM Monitor Stream,
440 currently there is only a total sum of network I/O statistics, no
442 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
443 APPLDATA monitor record, i.e. enables or disables monitoring this record
447 This can also be compiled as a module, which will be called
451 bool "No HZ timer ticks in idle"
453 Switches the regular HZ timer off when the system is going idle.
454 This helps z/VM to detect that the Linux system is idle. VM can
455 then "swap-out" this guest which reduces memory usage. It also
456 reduces the overhead of idle systems.
458 The HZ timer can be switched on/off via /proc/sys/kernel/hz_timer.
459 hz_timer=0 means HZ timer is disabled. hz_timer=1 means HZ
462 config NO_IDLE_HZ_INIT
463 bool "HZ timer in idle off by default"
464 depends on NO_IDLE_HZ
466 The HZ timer is switched off in idle by default. That means the
467 HZ timer is already disabled at boot time.
470 bool "s390 hypervisor file system support"
471 select SYS_HYPERVISOR
474 This is a virtual file system intended to provide accounting
475 information in an s390 hypervisor environment.
478 bool "kexec system call"
480 kexec is a system call that implements the ability to shutdown your
481 current kernel, and to start another kernel. It is like a reboot
482 but is independent of hardware/microcode support.
492 source "drivers/base/Kconfig"
494 source "drivers/connector/Kconfig"
496 source "drivers/scsi/Kconfig"
498 source "drivers/s390/Kconfig"
500 source "drivers/net/Kconfig"
504 menu "Instrumentation Support"
506 source "arch/s390/oprofile/Kconfig"
509 bool "Kprobes (EXPERIMENTAL)"
510 depends on EXPERIMENTAL && MODULES
512 Kprobes allows you to trap at almost any kernel address and
513 execute a callback function. register_kprobe() establishes
514 a probepoint and specifies the callback. Kprobes is useful
515 for kernel debugging, non-intrusive instrumentation and testing.
516 If in doubt, say "N".
520 source "arch/s390/Kconfig.debug"
522 source "security/Kconfig"
524 source "crypto/Kconfig"