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
76 select HAVE_KVM if 64BIT
77 select HAVE_ARCH_TRACEHOOK
78 select INIT_ALL_POSSIBLE
82 source "kernel/Kconfig.freezer"
86 comment "Processor type and features"
88 source "kernel/time/Kconfig"
93 Select this option if you have a 64 bit IBM zSeries machine
94 and want to use the 64 bit addressing mode.
101 bool "Symmetric multi-processing support"
103 This enables support for systems with more than one CPU. If you have
104 a system with only one CPU, like most personal computers, say N. If
105 you have a system with more than one CPU, say Y.
107 If you say N here, the kernel will run on single and multiprocessor
108 machines, but will use only one CPU of a multiprocessor machine. If
109 you say Y here, the kernel will run on many, but not all,
110 singleprocessor machines. On a singleprocessor machine, the kernel
111 will run faster if you say N here.
113 See also the SMP-HOWTO available at
114 <http://www.tldp.org/docs.html#howto>.
116 Even if you don't know what to do here, say Y.
119 int "Maximum number of CPUs (2-64)"
122 default "32" if !64BIT
123 default "64" if 64BIT
125 This allows you to specify the maximum number of CPUs which this
126 kernel will support. The maximum supported value is 64 and the
127 minimum value which makes sense is 2.
129 This is purely to save memory - each supported CPU adds
130 approximately sixteen kilobytes to the kernel image.
133 bool "Support for hot-pluggable CPUs"
138 Say Y here to be able to turn CPUs off and on. CPUs
139 can be controlled through /sys/devices/system/cpu/cpu#.
140 Say N if you want to disable CPU hotplug.
143 bool "IEEE FPU emulation"
146 This option is required for IEEE compliant floating point arithmetic
147 on older S/390 machines. Say Y unless you know your machine doesn't
151 bool "Kernel support for 31 bit emulation"
153 select COMPAT_BINFMT_ELF
155 Select this option if you want to enable your system kernel to
156 handle system-calls from ELF binaries for 31 bit ESA. This option
157 (and some other stuff like libraries and such) is needed for
158 executing 31 bit applications. It is safe to say "Y".
160 config SYSVIPC_COMPAT
162 depends on COMPAT && SYSVIPC
169 config S390_SWITCH_AMODE
170 bool "Switch kernel/user addressing modes"
172 This option allows to switch the addressing modes of kernel and user
173 space. The kernel parameter switch_amode=on will enable this feature,
174 default is disabled. Enabling this (via kernel parameter) on machines
175 earlier than IBM System z9-109 EC/BC will reduce system performance.
177 Note that this option will also be selected by selecting the execute
178 protection option below. Enabling the execute protection via the
179 noexec kernel parameter will also switch the addressing modes,
180 independent of the switch_amode kernel parameter.
183 config S390_EXEC_PROTECT
184 bool "Data execute protection"
185 select S390_SWITCH_AMODE
187 This option allows to enable a buffer overflow protection for user
188 space programs and it also selects the addressing mode option above.
189 The kernel parameter noexec=on will enable this feature and also
190 switch the addressing modes, default is disabled. Enabling this (via
191 kernel parameter) on machines earlier than IBM System z9-109 EC/BC
192 will reduce system performance.
194 comment "Code generation options"
197 prompt "Processor type"
201 bool "S/390 model G5 and G6"
204 Select this to build a 31 bit kernel that works
205 on all S/390 and zSeries machines.
208 bool "IBM eServer zSeries model z800 and z900"
210 Select this to optimize for zSeries machines. This
211 will enable some optimizations that are not available
212 on older 31 bit only CPUs.
215 bool "IBM eServer zSeries model z890 and z990"
217 Select this enable optimizations for model z890/z990.
218 This will be slightly faster but does not work on
219 older machines such as the z900.
224 Select this to enable optimizations for IBM System z9-109, IBM
225 System z9 Enterprise Class (z9 EC), and IBM System z9 Business
226 Class (z9 BC). The kernel will be slightly faster but will not
227 work on older machines such as the z990, z890, z900, and z800.
232 bool "Pack kernel stack"
234 This option enables the compiler option -mkernel-backchain if it
235 is available. If the option is available the compiler supports
236 the new stack layout which dramatically reduces the minimum stack
237 frame size. With an old compiler a non-leaf function needs a
238 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
239 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
240 and 24 byte on 64 bit.
242 Say Y if you are unsure.
245 bool "Use 8kb for kernel stack instead of 16kb"
246 depends on PACK_STACK && 64BIT && !LOCKDEP
248 If you say Y here and the compiler supports the -mkernel-backchain
249 option the kernel will use a smaller kernel stack size. The reduced
250 size is 8kb instead of 16kb. This allows to run more threads on a
251 system and reduces the pressure on the memory management for higher
252 order page allocations.
254 Say N if you are unsure.
257 bool "Detect kernel stack overflow"
259 This option enables the compiler option -mstack-guard and
260 -mstack-size if they are available. If the compiler supports them
261 it will emit additional code to each function prolog to trigger
262 an illegal operation if the kernel stack is about to overflow.
264 Say N if you are unsure.
267 int "Size of the guard area (128-1024)"
269 depends on CHECK_STACK
272 This allows you to specify the size of the guard area at the lower
273 end of the kernel stack. If the kernel stack points into the guard
274 area on function entry an illegal operation is triggered. The size
275 needs to be a power of 2. Please keep in mind that the size of an
276 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
277 The minimum size for the stack guard should be 256 for 31 bit and
281 bool "Emit compiler warnings for function with broken stack usage"
283 This option enables the compiler options -mwarn-framesize and
284 -mwarn-dynamicstack. If the compiler supports these options it
285 will generate warnings for function which either use alloca or
286 create a stack frame bigger then CONFIG_WARN_STACK_SIZE.
288 Say N if you are unsure.
290 config WARN_STACK_SIZE
291 int "Maximum frame size considered safe (128-2048)"
293 depends on WARN_STACK
296 This allows you to specify the maximum frame size a function may
297 have without the compiler complaining about it.
299 config ARCH_POPULATES_NODE_MAP
302 comment "Kernel preemption"
304 source "kernel/Kconfig.preempt"
306 config ARCH_SPARSEMEM_ENABLE
308 select SPARSEMEM_VMEMMAP_ENABLE
309 select SPARSEMEM_VMEMMAP
310 select SPARSEMEM_STATIC if !64BIT
312 config ARCH_SPARSEMEM_DEFAULT
315 config ARCH_SELECT_MEMORY_MODEL
318 config ARCH_ENABLE_MEMORY_HOTPLUG
322 config ARCH_ENABLE_MEMORY_HOTREMOVE
327 comment "I/O subsystem configuration"
329 config MACHCHK_WARNING
330 bool "Process warning machine checks"
332 Select this option if you want the machine check handler on IBM S/390 or
333 zSeries to process warning machine checks (e.g. on power failures).
337 tristate "QDIO support"
339 This driver provides the Queued Direct I/O base support for
342 To compile this driver as a module, choose M here: the
343 module will be called qdio.
348 bool "Extended debugging information"
351 Say Y here to get extended debugging output in
352 /sys/kernel/debug/s390dbf/qdio...
353 Warning: this option reduces the performance of the QDIO module.
358 tristate "Support for CHSC subchannels"
360 This driver allows usage of CHSC subchannels. A CHSC subchannel
361 is usually present on LPAR only.
362 The driver creates a device /dev/chsc, which may be used to
363 obtain I/O configuration information about the machine and
364 to issue asynchronous chsc commands (DANGEROUS).
365 You will usually only want to use this interface on a special
366 LPAR designated for system management.
368 To compile this driver as a module, choose M here: the
369 module will be called chsc_sch.
376 bool "Builtin IPL record support"
378 If you want to use the produced kernel to IPL directly from a
379 device, you have to merge a bootsector specific to the device
380 into the first bytes of the kernel. You will have to select the
384 prompt "IPL method generated into head.S"
388 Select "tape" if you want to IPL the image from a Tape.
390 Select "vm_reader" if you are running under VM/ESA and want
391 to IPL the image from the emulated card reader.
401 source "fs/Kconfig.binfmt"
403 config FORCE_MAX_ZONEORDER
408 bool "Show crashed user process info"
410 Say Y to print all process fault locations to the console. This is
411 a debugging option; you probably do not want to set it unless you
412 are an S390 port maintainer.
415 bool "Pseudo page fault support"
417 Select this option, if you want to use PFAULT pseudo page fault
418 handling under VM. If running native or in LPAR, this option
419 has no effect. If your VM does not support PFAULT, PAGEEX
420 pseudo page fault handling will be used.
421 Note that VM 4.2 supports PFAULT but has a bug in its
422 implementation that causes some problems.
423 Everybody who wants to run Linux under VM != VM4.2 should select
427 bool "VM shared kernel support"
429 Select this option, if you want to share the text segment of the
430 Linux kernel between different VM guests. This reduces memory
431 usage with lots of guests but greatly increases kernel size.
432 Also if a kernel was IPL'ed from a shared segment the kexec system
434 You should only select this option if you know what you are
435 doing and want to exploit this feature.
438 tristate "Cooperative memory management"
440 Select this option, if you want to enable the kernel interface
441 to reduce the memory size of the system. This is accomplished
442 by allocating pages of memory and put them "on hold". This only
443 makes sense for a system running under VM where the unused pages
444 will be reused by VM for other guest systems. The interface
445 allows an external monitor to balance memory of many systems.
446 Everybody who wants to run Linux under VM should select this
450 bool "/proc interface to cooperative memory management"
453 Select this option to enable the /proc interface to the
454 cooperative memory management.
457 bool "IUCV special message interface to cooperative memory management"
458 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
460 Select this option to enable the special message interface to
461 the cooperative memory management.
464 bool "Unused page notification"
466 This enables the notification of unused pages to the
467 hypervisor. The ESSA instruction is used to do the states
468 changes between a page that has content and the unused state.
471 bool "Virtual CPU timer support"
473 This provides a kernel interface for virtual CPU timers.
476 config VIRT_CPU_ACCOUNTING
477 bool "Base user process accounting on virtual cpu timer"
478 depends on VIRT_TIMER
480 Select this option to use CPU timer deltas to do user
484 bool "Linux - VM Monitor Stream, base infrastructure"
485 depends on PROC_FS && VIRT_TIMER=y
487 This provides a kernel interface for creating and updating z/VM APPLDATA
488 monitor records. The monitor records are updated at certain time
489 intervals, once the timer is started.
490 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
491 i.e. enables or disables monitoring on the Linux side.
492 A custom interval value (in seconds) can be written to
493 /proc/appldata/interval.
495 Defaults are 60 seconds interval and timer off.
496 The /proc entries can also be read from, showing the current settings.
499 tristate "Monitor memory management statistics"
500 depends on APPLDATA_BASE && VM_EVENT_COUNTERS
502 This provides memory management related data to the Linux - VM Monitor
503 Stream, like paging/swapping rate, memory utilisation, etc.
504 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
505 APPLDATA monitor record, i.e. enables or disables monitoring this record
509 The /proc entry can also be read from, showing the current settings.
511 This can also be compiled as a module, which will be called
515 tristate "Monitor OS statistics"
516 depends on APPLDATA_BASE
518 This provides OS related data to the Linux - VM Monitor Stream, like
519 CPU utilisation, etc.
520 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
521 APPLDATA monitor record, i.e. enables or disables monitoring this record
525 This can also be compiled as a module, which will be called
528 config APPLDATA_NET_SUM
529 tristate "Monitor overall network statistics"
530 depends on APPLDATA_BASE
532 This provides network related data to the Linux - VM Monitor Stream,
533 currently there is only a total sum of network I/O statistics, no
535 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
536 APPLDATA monitor record, i.e. enables or disables monitoring this record
540 This can also be compiled as a module, which will be called
543 source kernel/Kconfig.hz
546 bool "s390 hypervisor file system support"
547 select SYS_HYPERVISOR
550 This is a virtual file system intended to provide accounting
551 information in an s390 hypervisor environment.
554 bool "kexec system call"
556 kexec is a system call that implements the ability to shutdown your
557 current kernel, and to start another kernel. It is like a reboot
558 but is independent of hardware/microcode support.
561 tristate "zfcpdump support"
565 Select this option if you want to build an zfcpdump enabled kernel.
566 Refer to <file:Documentation/s390/zfcpdump.txt> for more details on this.
569 bool "s390 guest support for KVM (EXPERIMENTAL)"
570 depends on 64BIT && EXPERIMENTAL
573 select VIRTIO_CONSOLE
575 Select this option if you want to run the kernel as a guest under
576 the KVM hypervisor. This will add detection for KVM as well as a
577 virtio transport. If KVM is detected, the virtio console will be
589 source "drivers/Kconfig"
593 source "arch/s390/Kconfig.debug"
595 source "security/Kconfig"
597 source "crypto/Kconfig"
601 source "arch/s390/kvm/Kconfig"