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 bool "Symmetric multi-processing support"
54 This enables support for systems with more than one CPU. If you have
55 a system with only one CPU, like most personal computers, say N. If
56 you have a system with more than one CPU, say Y.
58 If you say N here, the kernel will run on single and multiprocessor
59 machines, but will use only one CPU of a multiprocessor machine. If
60 you say Y here, the kernel will run on many, but not all,
61 singleprocessor machines. On a singleprocessor machine, the kernel
62 will run faster if you say N here.
64 See also the <file:Documentation/smp.txt> and the SMP-HOWTO
65 available at <http://www.tldp.org/docs.html#howto>.
67 Even if you don't know what to do here, say Y.
70 int "Maximum number of CPUs (2-64)"
75 This allows you to specify the maximum number of CPUs which this
76 kernel will support. The maximum supported value is 64 and the
77 minimum value which makes sense is 2.
79 This is purely to save memory - each supported CPU adds
80 approximately sixteen kilobytes to the kernel image.
83 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
84 depends on SMP && HOTPLUG && EXPERIMENTAL
87 Say Y here to experiment with turning CPUs off and on. CPUs
88 can be controlled through /sys/devices/system/cpu/cpu#.
89 Say N if you want to disable CPU hotplug.
92 bool "IEEE FPU emulation"
95 This option is required for IEEE compliant floating point arithmetic
96 on older S/390 machines. Say Y unless you know your machine doesn't
100 bool "Kernel support for 31 bit emulation"
101 depends on ARCH_S390X
103 Select this option if you want to enable your system kernel to
104 handle system-calls from ELF binaries for 31 bit ESA. This option
105 (and some other stuff like libraries and such) is needed for
106 executing 31 bit applications. It is safe to say "Y".
110 depends on S390_SUPPORT
113 config SYSVIPC_COMPAT
115 depends on COMPAT && SYSVIPC
119 tristate "Kernel support for 31 bit ELF binaries"
120 depends on S390_SUPPORT
122 This allows you to run 32-bit Linux/ELF binaries on your zSeries
123 in 64 bit mode. Everybody wants this; say Y.
125 comment "Code generation options"
128 prompt "Processor type"
132 bool "S/390 model G5 and G6"
133 depends on ARCH_S390_31
135 Select this to build a 31 bit kernel that works
136 on all S/390 and zSeries machines.
139 bool "IBM eServer zSeries model z800 and z900"
141 Select this to optimize for zSeries machines. This
142 will enable some optimizations that are not available
143 on older 31 bit only CPUs.
146 bool "IBM eServer zSeries model z890 and z990"
148 Select this enable optimizations for model z890/z990.
149 This will be slightly faster but does not work on
150 older machines such as the z900.
155 bool "Pack kernel stack"
157 This option enables the compiler option -mkernel-backchain if it
158 is available. If the option is available the compiler supports
159 the new stack layout which dramatically reduces the minimum stack
160 frame size. With an old compiler a non-leaf function needs a
161 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
162 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
163 and 24 byte on 64 bit.
165 Say Y if you are unsure.
168 bool "Use 4kb/8kb for kernel stack instead of 8kb/16kb"
169 depends on PACK_STACK
171 If you say Y here and the compiler supports the -mkernel-backchain
172 option the kernel will use a smaller kernel stack size. For 31 bit
173 the reduced size is 4kb instead of 8kb and for 64 bit it is 8kb
174 instead of 16kb. This allows to run more thread on a system and
175 reduces the pressure on the memory management for higher order
178 Say N if you are unsure.
182 bool "Detect kernel stack overflow"
184 This option enables the compiler option -mstack-guard and
185 -mstack-size if they are available. If the compiler supports them
186 it will emit additional code to each function prolog to trigger
187 an illegal operation if the kernel stack is about to overflow.
189 Say N if you are unsure.
192 int "Size of the guard area (128-1024)"
194 depends on CHECK_STACK
197 This allows you to specify the size of the guard area at the lower
198 end of the kernel stack. If the kernel stack points into the guard
199 area on function entry an illegal operation is triggered. The size
200 needs to be a power of 2. Please keep in mind that the size of an
201 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
202 The minimum size for the stack guard should be 256 for 31 bit and
206 bool "Emit compiler warnings for function with broken stack usage"
208 This option enables the compiler options -mwarn-framesize and
209 -mwarn-dynamicstack. If the compiler supports these options it
210 will generate warnings for function which either use alloca or
211 create a stack frame bigger then CONFIG_WARN_STACK_SIZE.
213 Say N if you are unsure.
215 config WARN_STACK_SIZE
216 int "Maximum frame size considered safe (128-2048)"
218 depends on WARN_STACK
221 This allows you to specify the maximum frame size a function may
222 have without the compiler complaining about it.
224 comment "I/O subsystem configuration"
226 config MACHCHK_WARNING
227 bool "Process warning machine checks"
229 Select this option if you want the machine check handler on IBM S/390 or
230 zSeries to process warning machine checks (e.g. on power failures).
234 tristate "QDIO support"
236 This driver provides the Queued Direct I/O base support for the
237 IBM S/390 (G5 and G6) and eServer zSeries (z800, z890, z900 and z990).
239 For details please refer to the documentation provided by IBM at
240 <http://www10.software.ibm.com/developerworks/opensource/linux390>
242 To compile this driver as a module, choose M here: the
243 module will be called qdio.
247 config QDIO_PERF_STATS
248 bool "Performance statistics in /proc"
251 Say Y here to get performance statistics in /proc/qdio_perf
256 bool "Extended debugging information"
259 Say Y here to get extended debugging output in /proc/s390dbf/qdio...
260 Warning: this option reduces the performance of the QDIO module.
267 bool "Preemptible Kernel"
269 This option reduces the latency of the kernel when reacting to
270 real-time or interactive events by allowing a low priority process to
271 be preempted even if it is in kernel mode executing a system call.
272 This allows applications to run more reliably even when the system is
275 Say N if you are unsure.
278 bool "Builtin IPL record support"
280 If you want to use the produced kernel to IPL directly from a
281 device, you have to merge a bootsector specific to the device
282 into the first bytes of the kernel. You will have to select the
286 prompt "IPL method generated into head.S"
290 Select "tape" if you want to IPL the image from a Tape.
292 Select "vm_reader" if you are running under VM/ESA and want
293 to IPL the image from the emulated card reader.
303 source "fs/Kconfig.binfmt"
306 bool "Show crashed user process info"
308 Say Y to print all process fault locations to the console. This is
309 a debugging option; you probably do not want to set it unless you
310 are an S390 port maintainer.
313 bool "Pseudo page fault support"
315 Select this option, if you want to use PFAULT pseudo page fault
316 handling under VM. If running native or in LPAR, this option
317 has no effect. If your VM does not support PFAULT, PAGEEX
318 pseudo page fault handling will be used.
319 Note that VM 4.2 supports PFAULT but has a bug in its
320 implementation that causes some problems.
321 Everybody who wants to run Linux under VM != VM4.2 should select
325 bool "VM shared kernel support"
327 Select this option, if you want to share the text segment of the
328 Linux kernel between different VM guests. This reduces memory
329 usage with lots of guests but greatly increases kernel size.
330 You should only select this option if you know what you are
331 doing and want to exploit this feature.
334 tristate "Cooperative memory management"
336 Select this option, if you want to enable the kernel interface
337 to reduce the memory size of the system. This is accomplished
338 by allocating pages of memory and put them "on hold". This only
339 makes sense for a system running under VM where the unused pages
340 will be reused by VM for other guest systems. The interface
341 allows an external monitor to balance memory of many systems.
342 Everybody who wants to run Linux under VM should select this
346 bool "/proc interface to cooperative memory management"
349 Select this option to enable the /proc interface to the
350 cooperative memory management.
353 bool "IUCV special message interface to cooperative memory management"
354 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
356 Select this option to enable the special message interface to
357 the cooperative memory management.
360 bool "Virtual CPU timer support"
362 This provides a kernel interface for virtual CPU timers.
366 bool "Linux - VM Monitor Stream, base infrastructure"
367 depends on PROC_FS && VIRT_TIMER=y
369 This provides a kernel interface for creating and updating z/VM APPLDATA
370 monitor records. The monitor records are updated at certain time
371 intervals, once the timer is started.
372 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
373 i.e. enables or disables monitoring on the Linux side.
374 A custom interval value (in seconds) can be written to
375 /proc/appldata/interval.
377 Defaults are 60 seconds interval and timer off.
378 The /proc entries can also be read from, showing the current settings.
381 tristate "Monitor memory management statistics"
382 depends on APPLDATA_BASE
384 This provides memory management related data to the Linux - VM Monitor
385 Stream, like paging/swapping rate, memory utilisation, etc.
386 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
387 APPLDATA monitor record, i.e. enables or disables monitoring this record
391 The /proc entry can also be read from, showing the current settings.
393 This can also be compiled as a module, which will be called
397 tristate "Monitor OS statistics"
398 depends on APPLDATA_BASE
400 This provides OS related data to the Linux - VM Monitor Stream, like
401 CPU utilisation, etc.
402 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
403 APPLDATA monitor record, i.e. enables or disables monitoring this record
407 This can also be compiled as a module, which will be called
410 config APPLDATA_NET_SUM
411 tristate "Monitor overall network statistics"
412 depends on APPLDATA_BASE
414 This provides network related data to the Linux - VM Monitor Stream,
415 currently there is only a total sum of network I/O statistics, no
417 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
418 APPLDATA monitor record, i.e. enables or disables monitoring this record
422 This can also be compiled as a module, which will be called
426 bool "No HZ timer ticks in idle"
428 Switches the regular HZ timer off when the system is going idle.
429 This helps z/VM to detect that the Linux system is idle. VM can
430 then "swap-out" this guest which reduces memory usage. It also
431 reduces the overhead of idle systems.
433 The HZ timer can be switched on/off via /proc/sys/kernel/hz_timer.
434 hz_timer=0 means HZ timer is disabled. hz_timer=1 means HZ
437 config NO_IDLE_HZ_INIT
438 bool "HZ timer in idle off by default"
439 depends on NO_IDLE_HZ
441 The HZ timer is switched off in idle by default. That means the
442 HZ timer is already disabled at boot time.
450 source "drivers/base/Kconfig"
452 source "drivers/scsi/Kconfig"
454 source "drivers/s390/Kconfig"
460 source "arch/s390/oprofile/Kconfig"
462 source "arch/s390/Kconfig.debug"
464 source "kernel/vserver/Kconfig"
466 source "security/Kconfig"
468 source "crypto/Kconfig"