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_CALIBRATE_DELAY
21 config GENERIC_BUST_SPINLOCK
24 mainmenu "Linux Kernel Configuration"
39 comment "Processor type and features"
44 Select this option if you have a 64 bit IBM zSeries machine
45 and want to use the 64 bit addressing mode.
48 bool "Symmetric multi-processing support"
50 This enables support for systems with more than one CPU. If you have
51 a system with only one CPU, like most personal computers, say N. If
52 you have a system with more than one CPU, say Y.
54 If you say N here, the kernel will run on single and multiprocessor
55 machines, but will use only one CPU of a multiprocessor machine. If
56 you say Y here, the kernel will run on many, but not all,
57 singleprocessor machines. On a singleprocessor machine, the kernel
58 will run faster if you say N here.
60 See also the <file:Documentation/smp.txt> and the SMP-HOWTO
61 available at <http://www.tldp.org/docs.html#howto>.
63 Even if you don't know what to do here, say Y.
66 int "Maximum number of CPUs (2-64)"
71 This allows you to specify the maximum number of CPUs which this
72 kernel will support. The maximum supported value is 64 and the
73 minimum value which makes sense is 2.
75 This is purely to save memory - each supported CPU adds
76 approximately sixteen kilobytes to the kernel image.
79 bool "Support for hot-pluggable CPUs"
84 Say Y here to be able to turn CPUs off and on. CPUs
85 can be controlled through /sys/devices/system/cpu/cpu#.
86 Say N if you want to disable CPU hotplug.
89 bool "IEEE FPU emulation"
92 This option is required for IEEE compliant floating point arithmetic
93 on older S/390 machines. Say Y unless you know your machine doesn't
97 bool "Kernel support for 31 bit emulation"
100 Select this option if you want to enable your system kernel to
101 handle system-calls from ELF binaries for 31 bit ESA. This option
102 (and some other stuff like libraries and such) is needed for
103 executing 31 bit applications. It is safe to say "Y".
105 config SYSVIPC_COMPAT
107 depends on COMPAT && SYSVIPC
111 tristate "Kernel support for 31 bit ELF binaries"
114 This allows you to run 32-bit Linux/ELF binaries on your zSeries
115 in 64 bit mode. Everybody wants this; say Y.
117 comment "Code generation options"
120 prompt "Processor type"
124 bool "S/390 model G5 and G6"
127 Select this to build a 31 bit kernel that works
128 on all S/390 and zSeries machines.
131 bool "IBM eServer zSeries model z800 and z900"
133 Select this to optimize for zSeries machines. This
134 will enable some optimizations that are not available
135 on older 31 bit only CPUs.
138 bool "IBM eServer zSeries model z890 and z990"
140 Select this enable optimizations for model z890/z990.
141 This will be slightly faster but does not work on
142 older machines such as the z900.
147 bool "Pack kernel stack"
149 This option enables the compiler option -mkernel-backchain if it
150 is available. If the option is available the compiler supports
151 the new stack layout which dramatically reduces the minimum stack
152 frame size. With an old compiler a non-leaf function needs a
153 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
154 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
155 and 24 byte on 64 bit.
157 Say Y if you are unsure.
160 bool "Use 4kb/8kb for kernel stack instead of 8kb/16kb"
161 depends on PACK_STACK
163 If you say Y here and the compiler supports the -mkernel-backchain
164 option the kernel will use a smaller kernel stack size. For 31 bit
165 the reduced size is 4kb instead of 8kb and for 64 bit it is 8kb
166 instead of 16kb. This allows to run more thread on a system and
167 reduces the pressure on the memory management for higher order
170 Say N if you are unsure.
174 bool "Detect kernel stack overflow"
176 This option enables the compiler option -mstack-guard and
177 -mstack-size if they are available. If the compiler supports them
178 it will emit additional code to each function prolog to trigger
179 an illegal operation if the kernel stack is about to overflow.
181 Say N if you are unsure.
184 int "Size of the guard area (128-1024)"
186 depends on CHECK_STACK
189 This allows you to specify the size of the guard area at the lower
190 end of the kernel stack. If the kernel stack points into the guard
191 area on function entry an illegal operation is triggered. The size
192 needs to be a power of 2. Please keep in mind that the size of an
193 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
194 The minimum size for the stack guard should be 256 for 31 bit and
198 bool "Emit compiler warnings for function with broken stack usage"
200 This option enables the compiler options -mwarn-framesize and
201 -mwarn-dynamicstack. If the compiler supports these options it
202 will generate warnings for function which either use alloca or
203 create a stack frame bigger then CONFIG_WARN_STACK_SIZE.
205 Say N if you are unsure.
207 config WARN_STACK_SIZE
208 int "Maximum frame size considered safe (128-2048)"
210 depends on WARN_STACK
213 This allows you to specify the maximum frame size a function may
214 have without the compiler complaining about it.
218 comment "I/O subsystem configuration"
220 config MACHCHK_WARNING
221 bool "Process warning machine checks"
223 Select this option if you want the machine check handler on IBM S/390 or
224 zSeries to process warning machine checks (e.g. on power failures).
228 tristate "QDIO support"
230 This driver provides the Queued Direct I/O base support for
233 For details please refer to the documentation provided by IBM at
234 <http://www10.software.ibm.com/developerworks/opensource/linux390>
236 To compile this driver as a module, choose M here: the
237 module will be called qdio.
241 config QDIO_PERF_STATS
242 bool "Performance statistics in /proc"
245 Say Y here to get performance statistics in /proc/qdio_perf
250 bool "Extended debugging information"
253 Say Y here to get extended debugging output in
254 /sys/kernel/debug/s390dbf/qdio...
255 Warning: this option reduces the performance of the QDIO module.
262 bool "Preemptible Kernel"
264 This option reduces the latency of the kernel when reacting to
265 real-time or interactive events by allowing a low priority process to
266 be preempted even if it is in kernel mode executing a system call.
267 This allows applications to run more reliably even when the system is
270 Say N if you are unsure.
273 bool "Builtin IPL record support"
275 If you want to use the produced kernel to IPL directly from a
276 device, you have to merge a bootsector specific to the device
277 into the first bytes of the kernel. You will have to select the
281 prompt "IPL method generated into head.S"
285 Select "tape" if you want to IPL the image from a Tape.
287 Select "vm_reader" if you are running under VM/ESA and want
288 to IPL the image from the emulated card reader.
298 source "fs/Kconfig.binfmt"
301 bool "Show crashed user process info"
303 Say Y to print all process fault locations to the console. This is
304 a debugging option; you probably do not want to set it unless you
305 are an S390 port maintainer.
308 bool "Pseudo page fault support"
310 Select this option, if you want to use PFAULT pseudo page fault
311 handling under VM. If running native or in LPAR, this option
312 has no effect. If your VM does not support PFAULT, PAGEEX
313 pseudo page fault handling will be used.
314 Note that VM 4.2 supports PFAULT but has a bug in its
315 implementation that causes some problems.
316 Everybody who wants to run Linux under VM != VM4.2 should select
320 bool "VM shared kernel support"
322 Select this option, if you want to share the text segment of the
323 Linux kernel between different VM guests. This reduces memory
324 usage with lots of guests but greatly increases kernel size.
325 You should only select this option if you know what you are
326 doing and want to exploit this feature.
329 tristate "Cooperative memory management"
331 Select this option, if you want to enable the kernel interface
332 to reduce the memory size of the system. This is accomplished
333 by allocating pages of memory and put them "on hold". This only
334 makes sense for a system running under VM where the unused pages
335 will be reused by VM for other guest systems. The interface
336 allows an external monitor to balance memory of many systems.
337 Everybody who wants to run Linux under VM should select this
341 bool "/proc interface to cooperative memory management"
344 Select this option to enable the /proc interface to the
345 cooperative memory management.
348 bool "IUCV special message interface to cooperative memory management"
349 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
351 Select this option to enable the special message interface to
352 the cooperative memory management.
355 bool "Virtual CPU timer support"
357 This provides a kernel interface for virtual CPU timers.
360 config VIRT_CPU_ACCOUNTING
361 bool "Base user process accounting on virtual cpu timer"
362 depends on VIRT_TIMER
364 Select this option to use CPU timer deltas to do user
368 bool "Linux - VM Monitor Stream, base infrastructure"
369 depends on PROC_FS && VIRT_TIMER=y
371 This provides a kernel interface for creating and updating z/VM APPLDATA
372 monitor records. The monitor records are updated at certain time
373 intervals, once the timer is started.
374 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
375 i.e. enables or disables monitoring on the Linux side.
376 A custom interval value (in seconds) can be written to
377 /proc/appldata/interval.
379 Defaults are 60 seconds interval and timer off.
380 The /proc entries can also be read from, showing the current settings.
383 tristate "Monitor memory management statistics"
384 depends on APPLDATA_BASE
386 This provides memory management related data to the Linux - VM Monitor
387 Stream, like paging/swapping rate, memory utilisation, etc.
388 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
389 APPLDATA monitor record, i.e. enables or disables monitoring this record
393 The /proc entry can also be read from, showing the current settings.
395 This can also be compiled as a module, which will be called
399 tristate "Monitor OS statistics"
400 depends on APPLDATA_BASE
402 This provides OS related data to the Linux - VM Monitor Stream, like
403 CPU utilisation, etc.
404 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
405 APPLDATA monitor record, i.e. enables or disables monitoring this record
409 This can also be compiled as a module, which will be called
412 config APPLDATA_NET_SUM
413 tristate "Monitor overall network statistics"
414 depends on APPLDATA_BASE
416 This provides network related data to the Linux - VM Monitor Stream,
417 currently there is only a total sum of network I/O statistics, no
419 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
420 APPLDATA monitor record, i.e. enables or disables monitoring this record
424 This can also be compiled as a module, which will be called
428 bool "No HZ timer ticks in idle"
430 Switches the regular HZ timer off when the system is going idle.
431 This helps z/VM to detect that the Linux system is idle. VM can
432 then "swap-out" this guest which reduces memory usage. It also
433 reduces the overhead of idle systems.
435 The HZ timer can be switched on/off via /proc/sys/kernel/hz_timer.
436 hz_timer=0 means HZ timer is disabled. hz_timer=1 means HZ
439 config NO_IDLE_HZ_INIT
440 bool "HZ timer in idle off by default"
441 depends on NO_IDLE_HZ
443 The HZ timer is switched off in idle by default. That means the
444 HZ timer is already disabled at boot time.
447 bool "kexec system call (EXPERIMENTAL)"
448 depends on EXPERIMENTAL
450 kexec is a system call that implements the ability to shutdown your
451 current kernel, and to start another kernel. It is like a reboot
452 but is independent of hardware/microcode support.
462 source "drivers/base/Kconfig"
464 source "drivers/scsi/Kconfig"
466 source "drivers/s390/Kconfig"
468 source "drivers/net/Kconfig"
472 source "arch/s390/oprofile/Kconfig"
474 source "arch/s390/Kconfig.debug"
476 source "security/Kconfig"
478 source "crypto/Kconfig"