2 # For a description of the syntax of this configuration file,
3 # see Documentation/kbuild/kconfig-language.txt.
17 config LOCKDEP_SUPPORT
20 config STACKTRACE_SUPPORT
23 config HAVE_LATENCYTOP_SUPPORT
26 config RWSEM_GENERIC_SPINLOCK
29 config RWSEM_XCHGADD_ALGORITHM
32 config ARCH_HAS_ILOG2_U32
36 config ARCH_HAS_ILOG2_U64
40 config GENERIC_HWEIGHT
46 config GENERIC_CLOCKEVENTS
60 config GENERIC_LOCKBREAK
63 depends on SMP && PREEMPT
69 mainmenu "Linux Kernel Configuration"
75 select HAVE_KRETPROBES
81 comment "Processor type and features"
83 source "kernel/time/Kconfig"
88 Select this option if you have a 64 bit IBM zSeries machine
89 and want to use the 64 bit addressing mode.
96 bool "Symmetric multi-processing support"
98 This enables support for systems with more than one CPU. If you have
99 a system with only one CPU, like most personal computers, say N. If
100 you have a system with more than one CPU, say Y.
102 If you say N here, the kernel will run on single and multiprocessor
103 machines, but will use only one CPU of a multiprocessor machine. If
104 you say Y here, the kernel will run on many, but not all,
105 singleprocessor machines. On a singleprocessor machine, the kernel
106 will run faster if you say N here.
108 See also the SMP-HOWTO available at
109 <http://www.tldp.org/docs.html#howto>.
111 Even if you don't know what to do here, say Y.
114 int "Maximum number of CPUs (2-64)"
117 default "32" if !64BIT
118 default "64" if 64BIT
120 This allows you to specify the maximum number of CPUs which this
121 kernel will support. The maximum supported value is 64 and the
122 minimum value which makes sense is 2.
124 This is purely to save memory - each supported CPU adds
125 approximately sixteen kilobytes to the kernel image.
128 bool "Support for hot-pluggable CPUs"
133 Say Y here to be able to turn CPUs off and on. CPUs
134 can be controlled through /sys/devices/system/cpu/cpu#.
135 Say N if you want to disable CPU hotplug.
138 bool "IEEE FPU emulation"
141 This option is required for IEEE compliant floating point arithmetic
142 on older S/390 machines. Say Y unless you know your machine doesn't
146 bool "Kernel support for 31 bit emulation"
149 Select this option if you want to enable your system kernel to
150 handle system-calls from ELF binaries for 31 bit ESA. This option
151 (and some other stuff like libraries and such) is needed for
152 executing 31 bit applications. It is safe to say "Y".
154 config SYSVIPC_COMPAT
156 depends on COMPAT && SYSVIPC
163 config S390_SWITCH_AMODE
164 bool "Switch kernel/user addressing modes"
166 This option allows to switch the addressing modes of kernel and user
167 space. The kernel parameter switch_amode=on will enable this feature,
168 default is disabled. Enabling this (via kernel parameter) on machines
169 earlier than IBM System z9-109 EC/BC will reduce system performance.
171 Note that this option will also be selected by selecting the execute
172 protection option below. Enabling the execute protection via the
173 noexec kernel parameter will also switch the addressing modes,
174 independent of the switch_amode kernel parameter.
177 config S390_EXEC_PROTECT
178 bool "Data execute protection"
179 select S390_SWITCH_AMODE
181 This option allows to enable a buffer overflow protection for user
182 space programs and it also selects the addressing mode option above.
183 The kernel parameter noexec=on will enable this feature and also
184 switch the addressing modes, default is disabled. Enabling this (via
185 kernel parameter) on machines earlier than IBM System z9-109 EC/BC
186 will reduce system performance.
188 comment "Code generation options"
191 prompt "Processor type"
195 bool "S/390 model G5 and G6"
198 Select this to build a 31 bit kernel that works
199 on all S/390 and zSeries machines.
202 bool "IBM eServer zSeries model z800 and z900"
204 Select this to optimize for zSeries machines. This
205 will enable some optimizations that are not available
206 on older 31 bit only CPUs.
209 bool "IBM eServer zSeries model z890 and z990"
211 Select this enable optimizations for model z890/z990.
212 This will be slightly faster but does not work on
213 older machines such as the z900.
218 Select this to enable optimizations for IBM System z9-109, IBM
219 System z9 Enterprise Class (z9 EC), and IBM System z9 Business
220 Class (z9 BC). The kernel will be slightly faster but will not
221 work on older machines such as the z990, z890, z900, and z800.
226 bool "Pack kernel stack"
228 This option enables the compiler option -mkernel-backchain if it
229 is available. If the option is available the compiler supports
230 the new stack layout which dramatically reduces the minimum stack
231 frame size. With an old compiler a non-leaf function needs a
232 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
233 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
234 and 24 byte on 64 bit.
236 Say Y if you are unsure.
239 bool "Use 4kb/8kb for kernel stack instead of 8kb/16kb"
240 depends on PACK_STACK && !LOCKDEP
242 If you say Y here and the compiler supports the -mkernel-backchain
243 option the kernel will use a smaller kernel stack size. For 31 bit
244 the reduced size is 4kb instead of 8kb and for 64 bit it is 8kb
245 instead of 16kb. This allows to run more thread on a system and
246 reduces the pressure on the memory management for higher order
249 Say N if you are unsure.
253 bool "Detect kernel stack overflow"
255 This option enables the compiler option -mstack-guard and
256 -mstack-size if they are available. If the compiler supports them
257 it will emit additional code to each function prolog to trigger
258 an illegal operation if the kernel stack is about to overflow.
260 Say N if you are unsure.
263 int "Size of the guard area (128-1024)"
265 depends on CHECK_STACK
268 This allows you to specify the size of the guard area at the lower
269 end of the kernel stack. If the kernel stack points into the guard
270 area on function entry an illegal operation is triggered. The size
271 needs to be a power of 2. Please keep in mind that the size of an
272 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
273 The minimum size for the stack guard should be 256 for 31 bit and
277 bool "Emit compiler warnings for function with broken stack usage"
279 This option enables the compiler options -mwarn-framesize and
280 -mwarn-dynamicstack. If the compiler supports these options it
281 will generate warnings for function which either use alloca or
282 create a stack frame bigger then CONFIG_WARN_STACK_SIZE.
284 Say N if you are unsure.
286 config WARN_STACK_SIZE
287 int "Maximum frame size considered safe (128-2048)"
289 depends on WARN_STACK
292 This allows you to specify the maximum frame size a function may
293 have without the compiler complaining about it.
295 config ARCH_POPULATES_NODE_MAP
298 comment "Kernel preemption"
300 source "kernel/Kconfig.preempt"
304 comment "I/O subsystem configuration"
306 config MACHCHK_WARNING
307 bool "Process warning machine checks"
309 Select this option if you want the machine check handler on IBM S/390 or
310 zSeries to process warning machine checks (e.g. on power failures).
314 tristate "QDIO support"
316 This driver provides the Queued Direct I/O base support for
319 To compile this driver as a module, choose M here: the
320 module will be called qdio.
325 bool "Extended debugging information"
328 Say Y here to get extended debugging output in
329 /sys/kernel/debug/s390dbf/qdio...
330 Warning: this option reduces the performance of the QDIO module.
337 bool "Builtin IPL record support"
339 If you want to use the produced kernel to IPL directly from a
340 device, you have to merge a bootsector specific to the device
341 into the first bytes of the kernel. You will have to select the
345 prompt "IPL method generated into head.S"
349 Select "tape" if you want to IPL the image from a Tape.
351 Select "vm_reader" if you are running under VM/ESA and want
352 to IPL the image from the emulated card reader.
362 source "fs/Kconfig.binfmt"
364 config FORCE_MAX_ZONEORDER
369 bool "Show crashed user process info"
371 Say Y to print all process fault locations to the console. This is
372 a debugging option; you probably do not want to set it unless you
373 are an S390 port maintainer.
376 bool "Pseudo page fault support"
378 Select this option, if you want to use PFAULT pseudo page fault
379 handling under VM. If running native or in LPAR, this option
380 has no effect. If your VM does not support PFAULT, PAGEEX
381 pseudo page fault handling will be used.
382 Note that VM 4.2 supports PFAULT but has a bug in its
383 implementation that causes some problems.
384 Everybody who wants to run Linux under VM != VM4.2 should select
388 bool "VM shared kernel support"
390 Select this option, if you want to share the text segment of the
391 Linux kernel between different VM guests. This reduces memory
392 usage with lots of guests but greatly increases kernel size.
393 Also if a kernel was IPL'ed from a shared segment the kexec system
395 You should only select this option if you know what you are
396 doing and want to exploit this feature.
399 tristate "Cooperative memory management"
401 Select this option, if you want to enable the kernel interface
402 to reduce the memory size of the system. This is accomplished
403 by allocating pages of memory and put them "on hold". This only
404 makes sense for a system running under VM where the unused pages
405 will be reused by VM for other guest systems. The interface
406 allows an external monitor to balance memory of many systems.
407 Everybody who wants to run Linux under VM should select this
411 bool "/proc interface to cooperative memory management"
414 Select this option to enable the /proc interface to the
415 cooperative memory management.
418 bool "IUCV special message interface to cooperative memory management"
419 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
421 Select this option to enable the special message interface to
422 the cooperative memory management.
425 bool "Virtual CPU timer support"
427 This provides a kernel interface for virtual CPU timers.
430 config VIRT_CPU_ACCOUNTING
431 bool "Base user process accounting on virtual cpu timer"
432 depends on VIRT_TIMER
434 Select this option to use CPU timer deltas to do user
438 bool "Linux - VM Monitor Stream, base infrastructure"
439 depends on PROC_FS && VIRT_TIMER=y
441 This provides a kernel interface for creating and updating z/VM APPLDATA
442 monitor records. The monitor records are updated at certain time
443 intervals, once the timer is started.
444 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
445 i.e. enables or disables monitoring on the Linux side.
446 A custom interval value (in seconds) can be written to
447 /proc/appldata/interval.
449 Defaults are 60 seconds interval and timer off.
450 The /proc entries can also be read from, showing the current settings.
453 tristate "Monitor memory management statistics"
454 depends on APPLDATA_BASE && VM_EVENT_COUNTERS
456 This provides memory management related data to the Linux - VM Monitor
457 Stream, like paging/swapping rate, memory utilisation, etc.
458 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
459 APPLDATA monitor record, i.e. enables or disables monitoring this record
463 The /proc entry can also be read from, showing the current settings.
465 This can also be compiled as a module, which will be called
469 tristate "Monitor OS statistics"
470 depends on APPLDATA_BASE
472 This provides OS related data to the Linux - VM Monitor Stream, like
473 CPU utilisation, etc.
474 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
475 APPLDATA monitor record, i.e. enables or disables monitoring this record
479 This can also be compiled as a module, which will be called
482 config APPLDATA_NET_SUM
483 tristate "Monitor overall network statistics"
484 depends on APPLDATA_BASE
486 This provides network related data to the Linux - VM Monitor Stream,
487 currently there is only a total sum of network I/O statistics, no
489 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
490 APPLDATA monitor record, i.e. enables or disables monitoring this record
494 This can also be compiled as a module, which will be called
497 source kernel/Kconfig.hz
500 bool "s390 hypervisor file system support"
501 select SYS_HYPERVISOR
504 This is a virtual file system intended to provide accounting
505 information in an s390 hypervisor environment.
508 bool "kexec system call"
510 kexec is a system call that implements the ability to shutdown your
511 current kernel, and to start another kernel. It is like a reboot
512 but is independent of hardware/microcode support.
515 tristate "zfcpdump support"
519 Select this option if you want to build an zfcpdump enabled kernel.
520 Refer to <file:Documentation/s390/zfcpdump.txt> for more details on this.
532 source "drivers/Kconfig"
536 source "arch/s390/Kconfig.debug"
538 source "security/Kconfig"
540 source "crypto/Kconfig"