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
81 source "kernel/Kconfig.freezer"
85 comment "Processor type and features"
87 source "kernel/time/Kconfig"
92 Select this option if you have a 64 bit IBM zSeries machine
93 and want to use the 64 bit addressing mode.
100 bool "Symmetric multi-processing support"
102 This enables support for systems with more than one CPU. If you have
103 a system with only one CPU, like most personal computers, say N. If
104 you have a system with more than one CPU, say Y.
106 If you say N here, the kernel will run on single and multiprocessor
107 machines, but will use only one CPU of a multiprocessor machine. If
108 you say Y here, the kernel will run on many, but not all,
109 singleprocessor machines. On a singleprocessor machine, the kernel
110 will run faster if you say N here.
112 See also the SMP-HOWTO available at
113 <http://www.tldp.org/docs.html#howto>.
115 Even if you don't know what to do here, say Y.
118 int "Maximum number of CPUs (2-64)"
121 default "32" if !64BIT
122 default "64" if 64BIT
124 This allows you to specify the maximum number of CPUs which this
125 kernel will support. The maximum supported value is 64 and the
126 minimum value which makes sense is 2.
128 This is purely to save memory - each supported CPU adds
129 approximately sixteen kilobytes to the kernel image.
132 bool "Support for hot-pluggable CPUs"
137 Say Y here to be able to turn CPUs off and on. CPUs
138 can be controlled through /sys/devices/system/cpu/cpu#.
139 Say N if you want to disable CPU hotplug.
142 bool "IEEE FPU emulation"
145 This option is required for IEEE compliant floating point arithmetic
146 on older S/390 machines. Say Y unless you know your machine doesn't
150 bool "Kernel support for 31 bit emulation"
152 select COMPAT_BINFMT_ELF
154 Select this option if you want to enable your system kernel to
155 handle system-calls from ELF binaries for 31 bit ESA. This option
156 (and some other stuff like libraries and such) is needed for
157 executing 31 bit applications. It is safe to say "Y".
159 config SYSVIPC_COMPAT
161 depends on COMPAT && SYSVIPC
168 config S390_SWITCH_AMODE
169 bool "Switch kernel/user addressing modes"
171 This option allows to switch the addressing modes of kernel and user
172 space. The kernel parameter switch_amode=on will enable this feature,
173 default is disabled. Enabling this (via kernel parameter) on machines
174 earlier than IBM System z9-109 EC/BC will reduce system performance.
176 Note that this option will also be selected by selecting the execute
177 protection option below. Enabling the execute protection via the
178 noexec kernel parameter will also switch the addressing modes,
179 independent of the switch_amode kernel parameter.
182 config S390_EXEC_PROTECT
183 bool "Data execute protection"
184 select S390_SWITCH_AMODE
186 This option allows to enable a buffer overflow protection for user
187 space programs and it also selects the addressing mode option above.
188 The kernel parameter noexec=on will enable this feature and also
189 switch the addressing modes, default is disabled. Enabling this (via
190 kernel parameter) on machines earlier than IBM System z9-109 EC/BC
191 will reduce system performance.
193 comment "Code generation options"
196 prompt "Processor type"
200 bool "S/390 model G5 and G6"
203 Select this to build a 31 bit kernel that works
204 on all S/390 and zSeries machines.
207 bool "IBM eServer zSeries model z800 and z900"
209 Select this to optimize for zSeries machines. This
210 will enable some optimizations that are not available
211 on older 31 bit only CPUs.
214 bool "IBM eServer zSeries model z890 and z990"
216 Select this enable optimizations for model z890/z990.
217 This will be slightly faster but does not work on
218 older machines such as the z900.
223 Select this to enable optimizations for IBM System z9-109, IBM
224 System z9 Enterprise Class (z9 EC), and IBM System z9 Business
225 Class (z9 BC). The kernel will be slightly faster but will not
226 work on older machines such as the z990, z890, z900, and z800.
231 bool "Pack kernel stack"
233 This option enables the compiler option -mkernel-backchain if it
234 is available. If the option is available the compiler supports
235 the new stack layout which dramatically reduces the minimum stack
236 frame size. With an old compiler a non-leaf function needs a
237 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
238 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
239 and 24 byte on 64 bit.
241 Say Y if you are unsure.
244 bool "Use 4kb/8kb for kernel stack instead of 8kb/16kb"
245 depends on PACK_STACK && !LOCKDEP
247 If you say Y here and the compiler supports the -mkernel-backchain
248 option the kernel will use a smaller kernel stack size. For 31 bit
249 the reduced size is 4kb instead of 8kb and for 64 bit it is 8kb
250 instead of 16kb. This allows to run more thread on a system and
251 reduces the pressure on the memory management for higher order
254 Say N if you are unsure.
258 bool "Detect kernel stack overflow"
260 This option enables the compiler option -mstack-guard and
261 -mstack-size if they are available. If the compiler supports them
262 it will emit additional code to each function prolog to trigger
263 an illegal operation if the kernel stack is about to overflow.
265 Say N if you are unsure.
268 int "Size of the guard area (128-1024)"
270 depends on CHECK_STACK
273 This allows you to specify the size of the guard area at the lower
274 end of the kernel stack. If the kernel stack points into the guard
275 area on function entry an illegal operation is triggered. The size
276 needs to be a power of 2. Please keep in mind that the size of an
277 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
278 The minimum size for the stack guard should be 256 for 31 bit and
282 bool "Emit compiler warnings for function with broken stack usage"
284 This option enables the compiler options -mwarn-framesize and
285 -mwarn-dynamicstack. If the compiler supports these options it
286 will generate warnings for function which either use alloca or
287 create a stack frame bigger then CONFIG_WARN_STACK_SIZE.
289 Say N if you are unsure.
291 config WARN_STACK_SIZE
292 int "Maximum frame size considered safe (128-2048)"
294 depends on WARN_STACK
297 This allows you to specify the maximum frame size a function may
298 have without the compiler complaining about it.
300 config ARCH_POPULATES_NODE_MAP
303 comment "Kernel preemption"
305 source "kernel/Kconfig.preempt"
307 config ARCH_SPARSEMEM_ENABLE
309 select SPARSEMEM_VMEMMAP_ENABLE
310 select SPARSEMEM_VMEMMAP
311 select SPARSEMEM_STATIC if !64BIT
313 config ARCH_SPARSEMEM_DEFAULT
316 config ARCH_SELECT_MEMORY_MODEL
319 config ARCH_ENABLE_MEMORY_HOTPLUG
323 config ARCH_ENABLE_MEMORY_HOTREMOVE
328 comment "I/O subsystem configuration"
330 config MACHCHK_WARNING
331 bool "Process warning machine checks"
333 Select this option if you want the machine check handler on IBM S/390 or
334 zSeries to process warning machine checks (e.g. on power failures).
338 tristate "QDIO support"
340 This driver provides the Queued Direct I/O base support for
343 To compile this driver as a module, choose M here: the
344 module will be called qdio.
349 bool "Extended debugging information"
352 Say Y here to get extended debugging output in
353 /sys/kernel/debug/s390dbf/qdio...
354 Warning: this option reduces the performance of the QDIO module.
359 tristate "Support for CHSC subchannels"
361 This driver allows usage of CHSC subchannels. A CHSC subchannel
362 is usually present on LPAR only.
363 The driver creates a device /dev/chsc, which may be used to
364 obtain I/O configuration information about the machine and
365 to issue asynchronous chsc commands (DANGEROUS).
366 You will usually only want to use this interface on a special
367 LPAR designated for system management.
369 To compile this driver as a module, choose M here: the
370 module will be called chsc_sch.
377 bool "Builtin IPL record support"
379 If you want to use the produced kernel to IPL directly from a
380 device, you have to merge a bootsector specific to the device
381 into the first bytes of the kernel. You will have to select the
385 prompt "IPL method generated into head.S"
389 Select "tape" if you want to IPL the image from a Tape.
391 Select "vm_reader" if you are running under VM/ESA and want
392 to IPL the image from the emulated card reader.
402 source "fs/Kconfig.binfmt"
404 config FORCE_MAX_ZONEORDER
409 bool "Show crashed user process info"
411 Say Y to print all process fault locations to the console. This is
412 a debugging option; you probably do not want to set it unless you
413 are an S390 port maintainer.
416 bool "Pseudo page fault support"
418 Select this option, if you want to use PFAULT pseudo page fault
419 handling under VM. If running native or in LPAR, this option
420 has no effect. If your VM does not support PFAULT, PAGEEX
421 pseudo page fault handling will be used.
422 Note that VM 4.2 supports PFAULT but has a bug in its
423 implementation that causes some problems.
424 Everybody who wants to run Linux under VM != VM4.2 should select
428 bool "VM shared kernel support"
430 Select this option, if you want to share the text segment of the
431 Linux kernel between different VM guests. This reduces memory
432 usage with lots of guests but greatly increases kernel size.
433 Also if a kernel was IPL'ed from a shared segment the kexec system
435 You should only select this option if you know what you are
436 doing and want to exploit this feature.
439 tristate "Cooperative memory management"
441 Select this option, if you want to enable the kernel interface
442 to reduce the memory size of the system. This is accomplished
443 by allocating pages of memory and put them "on hold". This only
444 makes sense for a system running under VM where the unused pages
445 will be reused by VM for other guest systems. The interface
446 allows an external monitor to balance memory of many systems.
447 Everybody who wants to run Linux under VM should select this
451 bool "/proc interface to cooperative memory management"
454 Select this option to enable the /proc interface to the
455 cooperative memory management.
458 bool "IUCV special message interface to cooperative memory management"
459 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
461 Select this option to enable the special message interface to
462 the cooperative memory management.
465 bool "Unused page notification"
467 This enables the notification of unused pages to the
468 hypervisor. The ESSA instruction is used to do the states
469 changes between a page that has content and the unused state.
472 bool "Virtual CPU timer support"
474 This provides a kernel interface for virtual CPU timers.
477 config VIRT_CPU_ACCOUNTING
478 bool "Base user process accounting on virtual cpu timer"
479 depends on VIRT_TIMER
481 Select this option to use CPU timer deltas to do user
485 bool "Linux - VM Monitor Stream, base infrastructure"
486 depends on PROC_FS && VIRT_TIMER=y
488 This provides a kernel interface for creating and updating z/VM APPLDATA
489 monitor records. The monitor records are updated at certain time
490 intervals, once the timer is started.
491 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
492 i.e. enables or disables monitoring on the Linux side.
493 A custom interval value (in seconds) can be written to
494 /proc/appldata/interval.
496 Defaults are 60 seconds interval and timer off.
497 The /proc entries can also be read from, showing the current settings.
500 tristate "Monitor memory management statistics"
501 depends on APPLDATA_BASE && VM_EVENT_COUNTERS
503 This provides memory management related data to the Linux - VM Monitor
504 Stream, like paging/swapping rate, memory utilisation, etc.
505 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
506 APPLDATA monitor record, i.e. enables or disables monitoring this record
510 The /proc entry can also be read from, showing the current settings.
512 This can also be compiled as a module, which will be called
516 tristate "Monitor OS statistics"
517 depends on APPLDATA_BASE
519 This provides OS related data to the Linux - VM Monitor Stream, like
520 CPU utilisation, etc.
521 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
522 APPLDATA monitor record, i.e. enables or disables monitoring this record
526 This can also be compiled as a module, which will be called
529 config APPLDATA_NET_SUM
530 tristate "Monitor overall network statistics"
531 depends on APPLDATA_BASE
533 This provides network related data to the Linux - VM Monitor Stream,
534 currently there is only a total sum of network I/O statistics, no
536 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
537 APPLDATA monitor record, i.e. enables or disables monitoring this record
541 This can also be compiled as a module, which will be called
544 source kernel/Kconfig.hz
547 bool "s390 hypervisor file system support"
548 select SYS_HYPERVISOR
551 This is a virtual file system intended to provide accounting
552 information in an s390 hypervisor environment.
555 bool "kexec system call"
557 kexec is a system call that implements the ability to shutdown your
558 current kernel, and to start another kernel. It is like a reboot
559 but is independent of hardware/microcode support.
562 tristate "zfcpdump support"
566 Select this option if you want to build an zfcpdump enabled kernel.
567 Refer to <file:Documentation/s390/zfcpdump.txt> for more details on this.
570 bool "s390 guest support for KVM (EXPERIMENTAL)"
571 depends on 64BIT && EXPERIMENTAL
574 select VIRTIO_CONSOLE
576 Select this option if you want to run the kernel as a guest under
577 the KVM hypervisor. This will add detection for KVM as well as a
578 virtio transport. If KVM is detected, the virtio console will be
590 source "drivers/Kconfig"
594 source "arch/s390/Kconfig.debug"
596 source "security/Kconfig"
598 source "crypto/Kconfig"
602 source "arch/s390/kvm/Kconfig"