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_TIME_VSYSCALL
49 config GENERIC_CLOCKEVENTS
63 config GENERIC_LOCKBREAK
66 depends on SMP && PREEMPT
72 mainmenu "Linux Kernel Configuration"
78 select HAVE_KRETPROBES
79 select HAVE_KVM if 64BIT
80 select HAVE_ARCH_TRACEHOOK
84 source "kernel/Kconfig.freezer"
88 comment "Processor type and features"
90 source "kernel/time/Kconfig"
95 Select this option if you have a 64 bit IBM zSeries machine
96 and want to use the 64 bit addressing mode.
103 bool "Symmetric multi-processing support"
105 This enables support for systems with more than one CPU. If you have
106 a system with only one CPU, like most personal computers, say N. If
107 you have a system with more than one CPU, say Y.
109 If you say N here, the kernel will run on single and multiprocessor
110 machines, but will use only one CPU of a multiprocessor machine. If
111 you say Y here, the kernel will run on many, but not all,
112 singleprocessor machines. On a singleprocessor machine, the kernel
113 will run faster if you say N here.
115 See also the SMP-HOWTO available at
116 <http://www.tldp.org/docs.html#howto>.
118 Even if you don't know what to do here, say Y.
121 int "Maximum number of CPUs (2-64)"
124 default "32" if !64BIT
125 default "64" if 64BIT
127 This allows you to specify the maximum number of CPUs which this
128 kernel will support. The maximum supported value is 64 and the
129 minimum value which makes sense is 2.
131 This is purely to save memory - each supported CPU adds
132 approximately sixteen kilobytes to the kernel image.
135 bool "Support for hot-pluggable CPUs"
140 Say Y here to be able to turn CPUs off and on. CPUs
141 can be controlled through /sys/devices/system/cpu/cpu#.
142 Say N if you want to disable CPU hotplug.
145 bool "IEEE FPU emulation"
148 This option is required for IEEE compliant floating point arithmetic
149 on older S/390 machines. Say Y unless you know your machine doesn't
153 bool "Kernel support for 31 bit emulation"
155 select COMPAT_BINFMT_ELF
157 Select this option if you want to enable your system kernel to
158 handle system-calls from ELF binaries for 31 bit ESA. This option
159 (and some other stuff like libraries and such) is needed for
160 executing 31 bit applications. It is safe to say "Y".
162 config SYSVIPC_COMPAT
164 depends on COMPAT && SYSVIPC
171 config S390_SWITCH_AMODE
172 bool "Switch kernel/user addressing modes"
174 This option allows to switch the addressing modes of kernel and user
175 space. The kernel parameter switch_amode=on will enable this feature,
176 default is disabled. Enabling this (via kernel parameter) on machines
177 earlier than IBM System z9-109 EC/BC will reduce system performance.
179 Note that this option will also be selected by selecting the execute
180 protection option below. Enabling the execute protection via the
181 noexec kernel parameter will also switch the addressing modes,
182 independent of the switch_amode kernel parameter.
185 config S390_EXEC_PROTECT
186 bool "Data execute protection"
187 select S390_SWITCH_AMODE
189 This option allows to enable a buffer overflow protection for user
190 space programs and it also selects the addressing mode option above.
191 The kernel parameter noexec=on will enable this feature and also
192 switch the addressing modes, default is disabled. Enabling this (via
193 kernel parameter) on machines earlier than IBM System z9-109 EC/BC
194 will reduce system performance.
196 comment "Code generation options"
199 prompt "Processor type"
203 bool "S/390 model G5 and G6"
206 Select this to build a 31 bit kernel that works
207 on all S/390 and zSeries machines.
210 bool "IBM eServer zSeries model z800 and z900"
212 Select this to optimize for zSeries machines. This
213 will enable some optimizations that are not available
214 on older 31 bit only CPUs.
217 bool "IBM eServer zSeries model z890 and z990"
219 Select this enable optimizations for model z890/z990.
220 This will be slightly faster but does not work on
221 older machines such as the z900.
226 Select this to enable optimizations for IBM System z9-109, IBM
227 System z9 Enterprise Class (z9 EC), and IBM System z9 Business
228 Class (z9 BC). The kernel will be slightly faster but will not
229 work on older machines such as the z990, z890, z900, and z800.
234 bool "Pack kernel stack"
236 This option enables the compiler option -mkernel-backchain if it
237 is available. If the option is available the compiler supports
238 the new stack layout which dramatically reduces the minimum stack
239 frame size. With an old compiler a non-leaf function needs a
240 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
241 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
242 and 24 byte on 64 bit.
244 Say Y if you are unsure.
247 bool "Use 8kb for kernel stack instead of 16kb"
248 depends on PACK_STACK && 64BIT && !LOCKDEP
250 If you say Y here and the compiler supports the -mkernel-backchain
251 option the kernel will use a smaller kernel stack size. The reduced
252 size is 8kb instead of 16kb. This allows to run more threads on a
253 system and reduces the pressure on the memory management for higher
254 order page allocations.
256 Say N if you are unsure.
259 bool "Detect kernel stack overflow"
261 This option enables the compiler option -mstack-guard and
262 -mstack-size if they are available. If the compiler supports them
263 it will emit additional code to each function prolog to trigger
264 an illegal operation if the kernel stack is about to overflow.
266 Say N if you are unsure.
269 int "Size of the guard area (128-1024)"
271 depends on CHECK_STACK
274 This allows you to specify the size of the guard area at the lower
275 end of the kernel stack. If the kernel stack points into the guard
276 area on function entry an illegal operation is triggered. The size
277 needs to be a power of 2. Please keep in mind that the size of an
278 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
279 The minimum size for the stack guard should be 256 for 31 bit and
283 bool "Emit compiler warnings for function with broken stack usage"
285 This option enables the compiler options -mwarn-framesize and
286 -mwarn-dynamicstack. If the compiler supports these options it
287 will generate warnings for function which either use alloca or
288 create a stack frame bigger then CONFIG_WARN_STACK_SIZE.
290 Say N if you are unsure.
292 config WARN_STACK_SIZE
293 int "Maximum frame size considered safe (128-2048)"
295 depends on WARN_STACK
298 This allows you to specify the maximum frame size a function may
299 have without the compiler complaining about it.
301 config ARCH_POPULATES_NODE_MAP
304 comment "Kernel preemption"
306 source "kernel/Kconfig.preempt"
308 config ARCH_SPARSEMEM_ENABLE
310 select SPARSEMEM_VMEMMAP_ENABLE
311 select SPARSEMEM_VMEMMAP
312 select SPARSEMEM_STATIC if !64BIT
314 config ARCH_SPARSEMEM_DEFAULT
317 config ARCH_SELECT_MEMORY_MODEL
320 config ARCH_ENABLE_MEMORY_HOTPLUG
324 config ARCH_ENABLE_MEMORY_HOTREMOVE
329 comment "I/O subsystem configuration"
331 config MACHCHK_WARNING
332 bool "Process warning machine checks"
334 Select this option if you want the machine check handler on IBM S/390 or
335 zSeries to process warning machine checks (e.g. on power failures).
339 tristate "QDIO support"
341 This driver provides the Queued Direct I/O base support for
344 To compile this driver as a module, choose M here: the
345 module will be called qdio.
350 bool "Extended debugging information"
353 Say Y here to get extended debugging output in
354 /sys/kernel/debug/s390dbf/qdio...
355 Warning: this option reduces the performance of the QDIO module.
360 tristate "Support for CHSC subchannels"
362 This driver allows usage of CHSC subchannels. A CHSC subchannel
363 is usually present on LPAR only.
364 The driver creates a device /dev/chsc, which may be used to
365 obtain I/O configuration information about the machine and
366 to issue asynchronous chsc commands (DANGEROUS).
367 You will usually only want to use this interface on a special
368 LPAR designated for system management.
370 To compile this driver as a module, choose M here: the
371 module will be called chsc_sch.
378 bool "Builtin IPL record support"
380 If you want to use the produced kernel to IPL directly from a
381 device, you have to merge a bootsector specific to the device
382 into the first bytes of the kernel. You will have to select the
386 prompt "IPL method generated into head.S"
390 Select "tape" if you want to IPL the image from a Tape.
392 Select "vm_reader" if you are running under VM/ESA and want
393 to IPL the image from the emulated card reader.
403 source "fs/Kconfig.binfmt"
405 config FORCE_MAX_ZONEORDER
410 bool "Show crashed user process info"
412 Say Y to print all process fault locations to the console. This is
413 a debugging option; you probably do not want to set it unless you
414 are an S390 port maintainer.
417 bool "Pseudo page fault support"
419 Select this option, if you want to use PFAULT pseudo page fault
420 handling under VM. If running native or in LPAR, this option
421 has no effect. If your VM does not support PFAULT, PAGEEX
422 pseudo page fault handling will be used.
423 Note that VM 4.2 supports PFAULT but has a bug in its
424 implementation that causes some problems.
425 Everybody who wants to run Linux under VM != VM4.2 should select
429 bool "VM shared kernel support"
431 Select this option, if you want to share the text segment of the
432 Linux kernel between different VM guests. This reduces memory
433 usage with lots of guests but greatly increases kernel size.
434 Also if a kernel was IPL'ed from a shared segment the kexec system
436 You should only select this option if you know what you are
437 doing and want to exploit this feature.
440 tristate "Cooperative memory management"
442 Select this option, if you want to enable the kernel interface
443 to reduce the memory size of the system. This is accomplished
444 by allocating pages of memory and put them "on hold". This only
445 makes sense for a system running under VM where the unused pages
446 will be reused by VM for other guest systems. The interface
447 allows an external monitor to balance memory of many systems.
448 Everybody who wants to run Linux under VM should select this
452 bool "/proc interface to cooperative memory management"
455 Select this option to enable the /proc interface to the
456 cooperative memory management.
459 bool "IUCV special message interface to cooperative memory management"
460 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
462 Select this option to enable the special message interface to
463 the cooperative memory management.
466 bool "Unused page notification"
468 This enables the notification of unused pages to the
469 hypervisor. The ESSA instruction is used to do the states
470 changes between a page that has content and the unused state.
473 bool "Virtual CPU timer support"
475 This provides a kernel interface for virtual CPU timers.
478 config VIRT_CPU_ACCOUNTING
479 bool "Base user process accounting on virtual cpu timer"
480 depends on VIRT_TIMER
482 Select this option to use CPU timer deltas to do user
486 bool "Linux - VM Monitor Stream, base infrastructure"
487 depends on PROC_FS && VIRT_TIMER=y
489 This provides a kernel interface for creating and updating z/VM APPLDATA
490 monitor records. The monitor records are updated at certain time
491 intervals, once the timer is started.
492 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
493 i.e. enables or disables monitoring on the Linux side.
494 A custom interval value (in seconds) can be written to
495 /proc/appldata/interval.
497 Defaults are 60 seconds interval and timer off.
498 The /proc entries can also be read from, showing the current settings.
501 tristate "Monitor memory management statistics"
502 depends on APPLDATA_BASE && VM_EVENT_COUNTERS
504 This provides memory management related data to the Linux - VM Monitor
505 Stream, like paging/swapping rate, memory utilisation, etc.
506 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
507 APPLDATA monitor record, i.e. enables or disables monitoring this record
511 The /proc entry can also be read from, showing the current settings.
513 This can also be compiled as a module, which will be called
517 tristate "Monitor OS statistics"
518 depends on APPLDATA_BASE
520 This provides OS related data to the Linux - VM Monitor Stream, like
521 CPU utilisation, etc.
522 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
523 APPLDATA monitor record, i.e. enables or disables monitoring this record
527 This can also be compiled as a module, which will be called
530 config APPLDATA_NET_SUM
531 tristate "Monitor overall network statistics"
532 depends on APPLDATA_BASE
534 This provides network related data to the Linux - VM Monitor Stream,
535 currently there is only a total sum of network I/O statistics, no
537 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
538 APPLDATA monitor record, i.e. enables or disables monitoring this record
542 This can also be compiled as a module, which will be called
545 source kernel/Kconfig.hz
548 bool "s390 hypervisor file system support"
549 select SYS_HYPERVISOR
552 This is a virtual file system intended to provide accounting
553 information in an s390 hypervisor environment.
556 bool "kexec system call"
558 kexec is a system call that implements the ability to shutdown your
559 current kernel, and to start another kernel. It is like a reboot
560 but is independent of hardware/microcode support.
563 tristate "zfcpdump support"
567 Select this option if you want to build an zfcpdump enabled kernel.
568 Refer to <file:Documentation/s390/zfcpdump.txt> for more details on this.
571 bool "s390 guest support for KVM (EXPERIMENTAL)"
572 depends on 64BIT && EXPERIMENTAL
575 select VIRTIO_CONSOLE
577 Select this option if you want to run the kernel as a guest under
578 the KVM hypervisor. This will add detection for KVM as well as a
579 virtio transport. If KVM is detected, the virtio console will be
591 source "drivers/Kconfig"
595 source "arch/s390/Kconfig.debug"
597 source "security/Kconfig"
599 source "crypto/Kconfig"
603 source "arch/s390/kvm/Kconfig"