2 # For a description of the syntax of this configuration file,
3 # see Documentation/kbuild/kconfig-language.txt.
10 config RWSEM_GENERIC_SPINLOCK
13 config RWSEM_XCHGADD_ALGORITHM
17 config GENERIC_BUST_SPINLOCK
20 mainmenu "Linux Kernel Configuration"
29 depends on ARCH_S390X = 'n'
35 comment "Processor type and features"
40 Select this option if you have a 64 bit IBM zSeries machine
41 and want to use the 64 bit addressing mode.
48 depends on ARCH_S390X = 'n'
52 prompt "Processor type"
56 bool "S/390 model G5 and G6"
57 depends on ARCH_S390_31
59 Select this to build a 31 bit kernel that works
60 on all S/390 and zSeries machines.
63 bool "IBM eServer zSeries model z800 and z900"
65 Select this to optimize for zSeries machines. This
66 will enable some optimizations that are not available
67 on older 31 bit only CPUs.
70 bool "IBM eServer zSeries model z990"
72 Select this enable optimizations for model z990.
73 This will be slightly faster but does not work on
74 older machines such as the z900.
80 bool "Symmetric multi-processing support"
82 This enables support for systems with more than one CPU. If you have
83 a system with only one CPU, like most personal computers, say N. If
84 you have a system with more than one CPU, say Y.
86 If you say N here, the kernel will run on single and multiprocessor
87 machines, but will use only one CPU of a multiprocessor machine. If
88 you say Y here, the kernel will run on many, but not all,
89 singleprocessor machines. On a singleprocessor machine, the kernel
90 will run faster if you say N here.
92 See also the <file:Documentation/smp.txt> and the SMP-HOWTO
93 available at <http://www.tldp.org/docs.html#howto>.
95 Even if you don't know what to do here, say Y.
98 int "Maximum number of CPUs (2-64)"
103 This allows you to specify the maximum number of CPUs which this
104 kernel will support. The maximum supported value is 64 and the
105 minimum value which makes sense is 2.
107 This is purely to save memory - each supported CPU adds
108 approximately sixteen kilobytes to the kernel image.
111 bool "IEEE FPU emulation"
114 This option is required for IEEE compliant floating point arithmetic
115 on older S/390 machines. Say Y unless you know your machine doesn't
119 bool "Kernel support for 31 bit emulation"
120 depends on ARCH_S390X
122 Select this option if you want to enable your system kernel to
123 handle system-calls from ELF binaries for 31 bit ESA. This option
124 (and some other stuff like libraries and such) is needed for
125 executing 31 bit applications. It is safe to say "Y".
129 depends on S390_SUPPORT
132 config SYSVIPC_COMPAT
134 depends on COMPAT && SYSVIPC
138 tristate "Kernel support for 31 bit ELF binaries"
139 depends on S390_SUPPORT
141 This allows you to run 32-bit Linux/ELF binaries on your zSeries
142 in 64 bit mode. Everybody wants this; say Y.
144 comment "I/O subsystem configuration"
146 config MACHCHK_WARNING
147 bool "Process warning machine checks"
149 Select this option if you want the machine check handler on IBM S/390 or
150 zSeries to process warning machine checks (e.g. on power failures).
154 tristate "QDIO support"
156 This driver provides the Queued Direct I/O base support for the
157 IBM S/390 (G5 and G6) and eServer zSeries (z800, z900 and z990).
159 For details please refer to the documentation provided by IBM at
160 <http://www10.software.ibm.com/developerworks/opensource/linux390>
162 To compile this driver as a module, choose M here: the
163 module will be called qdio.
167 config QDIO_PERF_STATS
168 bool "Performance statistics in /proc"
171 Say Y here to get performance statistics in /proc/qdio_perf
178 bool "Preemptible Kernel"
180 This option reduces the latency of the kernel when reacting to
181 real-time or interactive events by allowing a low priority process to
182 be preempted even if it is in kernel mode executing a system call.
183 This allows applications to run more reliably even when the system is
186 Say N if you are unsure.
189 bool "Builtin IPL record support"
191 If you want to use the produced kernel to IPL directly from a
192 device, you have to merge a bootsector specific to the device
193 into the first bytes of the kernel. You will have to select the
197 prompt "IPL method generated into head.S"
201 Select "tape" if you want to IPL the image from a Tape.
203 Select "vm_reader" if you are running under VM/ESA and want
204 to IPL the image from the emulated card reader.
214 source "fs/Kconfig.binfmt"
217 bool "Show crashed user process info"
219 Say Y to print all process fault locations to the console. This is
220 a debugging option; you probably do not want to set it unless you
221 are an S390 port maintainer.
224 bool "Pseudo page fault support"
226 Select this option, if you want to use PFAULT pseudo page fault
227 handling under VM. If running native or in LPAR, this option
228 has no effect. If your VM does not support PFAULT, PAGEEX
229 pseudo page fault handling will be used.
230 Note that VM 4.2 supports PFAULT but has a bug in its
231 implementation that causes some problems.
232 Everybody who wants to run Linux under VM != VM4.2 should select
236 bool "VM shared kernel support"
238 Select this option, if you want to share the text segment of the
239 Linux kernel between different VM guests. This reduces memory
240 usage with lots of guests but greatly increases kernel size.
241 You should only select this option if you know what you are
242 doing and want to exploit this feature.
245 tristate "Cooperative memory management"
247 Select this option, if you want to enable the kernel interface
248 to reduce the memory size of the system. This is accomplished
249 by allocating pages of memory and put them "on hold". This only
250 makes sense for a system running under VM where the unused pages
251 will be reused by VM for other guest systems. The interface
252 allows an external monitor to balance memory of many systems.
253 Everybody who wants to run Linux under VM should select this
257 bool "/proc interface to cooperative memory management"
260 Select this option to enable the /proc interface to the
261 cooperative memory management.
264 bool "IUCV special message interface to cooperative memory management"
265 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
267 Select this option to enable the special message interface to
268 the cooperative memory management.
271 bool "Virtual CPU timer support"
273 This provides a kernel interface for virtual CPU timers.
277 bool "Linux - VM Monitor Stream, base infrastructure"
278 depends on PROC_FS && VIRT_TIMER=y
280 This provides a kernel interface for creating and updating z/VM APPLDATA
281 monitor records. The monitor records are updated at certain time
282 intervals, once the timer is started.
283 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
284 i.e. enables or disables monitoring on the Linux side.
285 A custom interval value (in seconds) can be written to
286 /proc/appldata/interval.
288 Defaults are 60 seconds interval and timer off.
289 The /proc entries can also be read from, showing the current settings.
292 tristate "Monitor memory management statistics"
293 depends on APPLDATA_BASE
295 This provides memory management related data to the Linux - VM Monitor
296 Stream, like paging/swapping rate, memory utilisation, etc.
297 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
298 APPLDATA monitor record, i.e. enables or disables monitoring this record
302 The /proc entry can also be read from, showing the current settings.
304 This can also be compiled as a module, which will be called
308 tristate "Monitor OS statistics"
309 depends on APPLDATA_BASE
311 This provides OS related data to the Linux - VM Monitor Stream, like
312 CPU utilisation, etc.
313 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
314 APPLDATA monitor record, i.e. enables or disables monitoring this record
318 This can also be compiled as a module, which will be called
321 config APPLDATA_NET_SUM
322 tristate "Monitor overall network statistics"
323 depends on APPLDATA_BASE
325 This provides network related data to the Linux - VM Monitor Stream,
326 currently there is only a total sum of network I/O statistics, no
328 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
329 APPLDATA monitor record, i.e. enables or disables monitoring this record
333 This can also be compiled as a module, which will be called
337 bool "No HZ timer ticks in idle"
339 Switches the regular HZ timer off when the system is going idle.
340 This helps z/VM to detect that the Linux system is idle. VM can
341 then "swap-out" this guest which reduces memory usage. It also
342 reduces the overhead of idle systems.
344 The HZ timer can be switched on/off via /proc/sys/kernel/hz_timer.
345 hz_timer=0 means HZ timer is disabled. hz_timer=1 means HZ
348 config NO_IDLE_HZ_INIT
349 bool "HZ timer in idle off by default"
350 depends on NO_IDLE_HZ
352 The HZ timer is switched off in idle by default. That means the
353 HZ timer is already disabled at boot time.
361 source "drivers/base/Kconfig"
363 source "drivers/scsi/Kconfig"
365 source "drivers/s390/Kconfig"
371 source "arch/s390/oprofile/Kconfig"
373 menu "Kernel hacking"
376 bool "Kernel debugging"
378 Say Y here if you are developing drivers or trying to debug and
379 identify kernel problems.
382 bool "Magic SysRq key"
383 depends on DEBUG_KERNEL
385 If you say Y here, you will have some control over the system even
386 if the system crashes for example during kernel debugging (e.g., you
387 will be able to flush the buffer cache to disk, reboot the system
388 immediately or dump some status information). This is accomplished
389 by pressing various keys while holding SysRq (Alt+PrintScreen). It
390 also works on a serial console (on PC hardware at least), if you
391 send a BREAK and then within 5 seconds a command keypress. The
392 keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
393 unless you really know what this hack does.
396 bool "Debug memory allocations"
397 depends on DEBUG_KERNEL
399 Say Y here to have the kernel do limited verification on memory
400 allocation as well as poisoning memory on free to catch use of freed
404 bool "Load all symbols for debugging/kksymoops"
405 depends on DEBUG_KERNEL
407 Say Y here to let the kernel print out symbolic crash information and
408 symbolic stack backtraces. This increases the size of the kernel
409 somewhat, as all symbols have to be loaded into the kernel image.
412 bool "Compile the kernel with debug info"
413 depends on DEBUG_KERNEL
415 If you say Y here the resulting kernel image will include
416 debugging info resulting in a larger kernel image.
417 Say Y here only if you plan to use gdb to debug the kernel.
418 If you don't debug the kernel, you can say N.
420 config DEBUG_SPINLOCK_SLEEP
421 bool "Sleep-inside-spinlock checking"
423 If you say Y here, various routines which may sleep will become very
424 noisy if they are called with a spinlock held.
428 source "kernel/vserver/Kconfig"
430 source "security/Kconfig"
432 source "crypto/Kconfig"