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 config VIRT_CPU_ACCOUNTING
75 mainmenu "Linux Kernel Configuration"
79 select USE_GENERIC_SMP_HELPERS if SMP
80 select HAVE_FUNCTION_TRACER
83 select HAVE_KRETPROBES
84 select HAVE_KVM if 64BIT
85 select HAVE_ARCH_TRACEHOOK
86 select INIT_ALL_POSSIBLE
90 source "kernel/Kconfig.freezer"
94 comment "Processor type and features"
96 source "kernel/time/Kconfig"
101 Select this option if you have a 64 bit IBM zSeries machine
102 and want to use the 64 bit addressing mode.
109 bool "Symmetric multi-processing support"
111 This enables support for systems with more than one CPU. If you have
112 a system with only one CPU, like most personal computers, say N. If
113 you have a system with more than one CPU, say Y.
115 If you say N here, the kernel will run on single and multiprocessor
116 machines, but will use only one CPU of a multiprocessor machine. If
117 you say Y here, the kernel will run on many, but not all,
118 singleprocessor machines. On a singleprocessor machine, the kernel
119 will run faster if you say N here.
121 See also the SMP-HOWTO available at
122 <http://www.tldp.org/docs.html#howto>.
124 Even if you don't know what to do here, say Y.
127 int "Maximum number of CPUs (2-64)"
130 default "32" if !64BIT
131 default "64" if 64BIT
133 This allows you to specify the maximum number of CPUs which this
134 kernel will support. The maximum supported value is 64 and the
135 minimum value which makes sense is 2.
137 This is purely to save memory - each supported CPU adds
138 approximately sixteen kilobytes to the kernel image.
141 bool "Support for hot-pluggable CPUs"
146 Say Y here to be able to turn CPUs off and on. CPUs
147 can be controlled through /sys/devices/system/cpu/cpu#.
148 Say N if you want to disable CPU hotplug.
151 bool "IEEE FPU emulation"
154 This option is required for IEEE compliant floating point arithmetic
155 on older S/390 machines. Say Y unless you know your machine doesn't
159 bool "Kernel support for 31 bit emulation"
161 select COMPAT_BINFMT_ELF
163 Select this option if you want to enable your system kernel to
164 handle system-calls from ELF binaries for 31 bit ESA. This option
165 (and some other stuff like libraries and such) is needed for
166 executing 31 bit applications. It is safe to say "Y".
168 config SYSVIPC_COMPAT
170 depends on COMPAT && SYSVIPC
177 config S390_SWITCH_AMODE
178 bool "Switch kernel/user addressing modes"
180 This option allows to switch the addressing modes of kernel and user
181 space. The kernel parameter switch_amode=on will enable this feature,
182 default is disabled. Enabling this (via kernel parameter) on machines
183 earlier than IBM System z9-109 EC/BC will reduce system performance.
185 Note that this option will also be selected by selecting the execute
186 protection option below. Enabling the execute protection via the
187 noexec kernel parameter will also switch the addressing modes,
188 independent of the switch_amode kernel parameter.
191 config S390_EXEC_PROTECT
192 bool "Data execute protection"
193 select S390_SWITCH_AMODE
195 This option allows to enable a buffer overflow protection for user
196 space programs and it also selects the addressing mode option above.
197 The kernel parameter noexec=on will enable this feature and also
198 switch the addressing modes, default is disabled. Enabling this (via
199 kernel parameter) on machines earlier than IBM System z9-109 EC/BC
200 will reduce system performance.
202 comment "Code generation options"
205 prompt "Processor type"
209 bool "S/390 model G5 and G6"
212 Select this to build a 31 bit kernel that works
213 on all S/390 and zSeries machines.
216 bool "IBM eServer zSeries model z800 and z900"
218 Select this to optimize for zSeries machines. This
219 will enable some optimizations that are not available
220 on older 31 bit only CPUs.
223 bool "IBM eServer zSeries model z890 and z990"
225 Select this enable optimizations for model z890/z990.
226 This will be slightly faster but does not work on
227 older machines such as the z900.
232 Select this to enable optimizations for IBM System z9-109, IBM
233 System z9 Enterprise Class (z9 EC), and IBM System z9 Business
234 Class (z9 BC). The kernel will be slightly faster but will not
235 work on older machines such as the z990, z890, z900, and z800.
238 bool "IBM System z10"
240 Select this to enable optimizations for IBM System z10. The
241 kernel will be slightly faster but will not work on older
242 machines such as the z990, z890, z900, z800, z9-109, z9-ec
248 bool "Pack kernel stack"
250 This option enables the compiler option -mkernel-backchain if it
251 is available. If the option is available the compiler supports
252 the new stack layout which dramatically reduces the minimum stack
253 frame size. With an old compiler a non-leaf function needs a
254 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
255 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
256 and 24 byte on 64 bit.
258 Say Y if you are unsure.
261 bool "Use 8kb for kernel stack instead of 16kb"
262 depends on PACK_STACK && 64BIT && !LOCKDEP
264 If you say Y here and the compiler supports the -mkernel-backchain
265 option the kernel will use a smaller kernel stack size. The reduced
266 size is 8kb instead of 16kb. This allows to run more threads on a
267 system and reduces the pressure on the memory management for higher
268 order page allocations.
270 Say N if you are unsure.
273 bool "Detect kernel stack overflow"
275 This option enables the compiler option -mstack-guard and
276 -mstack-size if they are available. If the compiler supports them
277 it will emit additional code to each function prolog to trigger
278 an illegal operation if the kernel stack is about to overflow.
280 Say N if you are unsure.
283 int "Size of the guard area (128-1024)"
285 depends on CHECK_STACK
288 This allows you to specify the size of the guard area at the lower
289 end of the kernel stack. If the kernel stack points into the guard
290 area on function entry an illegal operation is triggered. The size
291 needs to be a power of 2. Please keep in mind that the size of an
292 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
293 The minimum size for the stack guard should be 256 for 31 bit and
297 bool "Emit compiler warnings for function with broken stack usage"
299 This option enables the compiler options -mwarn-framesize and
300 -mwarn-dynamicstack. If the compiler supports these options it
301 will generate warnings for function which either use alloca or
302 create a stack frame bigger than CONFIG_WARN_STACK_SIZE.
304 Say N if you are unsure.
306 config WARN_STACK_SIZE
307 int "Maximum frame size considered safe (128-2048)"
309 depends on WARN_STACK
312 This allows you to specify the maximum frame size a function may
313 have without the compiler complaining about it.
315 config ARCH_POPULATES_NODE_MAP
318 comment "Kernel preemption"
320 source "kernel/Kconfig.preempt"
322 config ARCH_SPARSEMEM_ENABLE
324 select SPARSEMEM_VMEMMAP_ENABLE
325 select SPARSEMEM_VMEMMAP
326 select SPARSEMEM_STATIC if !64BIT
328 config ARCH_SPARSEMEM_DEFAULT
331 config ARCH_SELECT_MEMORY_MODEL
334 config ARCH_ENABLE_MEMORY_HOTPLUG
338 config ARCH_ENABLE_MEMORY_HOTREMOVE
343 comment "I/O subsystem configuration"
345 config MACHCHK_WARNING
346 bool "Process warning machine checks"
348 Select this option if you want the machine check handler on IBM S/390 or
349 zSeries to process warning machine checks (e.g. on power failures).
353 tristate "QDIO support"
355 This driver provides the Queued Direct I/O base support for
358 To compile this driver as a module, choose M here: the
359 module will be called qdio.
364 tristate "Support for CHSC subchannels"
366 This driver allows usage of CHSC subchannels. A CHSC subchannel
367 is usually present on LPAR only.
368 The driver creates a device /dev/chsc, which may be used to
369 obtain I/O configuration information about the machine and
370 to issue asynchronous chsc commands (DANGEROUS).
371 You will usually only want to use this interface on a special
372 LPAR designated for system management.
374 To compile this driver as a module, choose M here: the
375 module will be called chsc_sch.
382 bool "Builtin IPL record support"
384 If you want to use the produced kernel to IPL directly from a
385 device, you have to merge a bootsector specific to the device
386 into the first bytes of the kernel. You will have to select the
390 prompt "IPL method generated into head.S"
394 Select "tape" if you want to IPL the image from a Tape.
396 Select "vm_reader" if you are running under VM/ESA and want
397 to IPL the image from the emulated card reader.
407 source "fs/Kconfig.binfmt"
409 config FORCE_MAX_ZONEORDER
414 bool "Show crashed user process info"
416 Say Y to print all process fault locations to the console. This is
417 a debugging option; you probably do not want to set it unless you
418 are an S390 port maintainer.
421 bool "Pseudo page fault support"
423 Select this option, if you want to use PFAULT pseudo page fault
424 handling under VM. If running native or in LPAR, this option
425 has no effect. If your VM does not support PFAULT, PAGEEX
426 pseudo page fault handling will be used.
427 Note that VM 4.2 supports PFAULT but has a bug in its
428 implementation that causes some problems.
429 Everybody who wants to run Linux under VM != VM4.2 should select
433 bool "VM shared kernel support"
435 Select this option, if you want to share the text segment of the
436 Linux kernel between different VM guests. This reduces memory
437 usage with lots of guests but greatly increases kernel size.
438 Also if a kernel was IPL'ed from a shared segment the kexec system
440 You should only select this option if you know what you are
441 doing and want to exploit this feature.
444 tristate "Cooperative memory management"
446 Select this option, if you want to enable the kernel interface
447 to reduce the memory size of the system. This is accomplished
448 by allocating pages of memory and put them "on hold". This only
449 makes sense for a system running under VM where the unused pages
450 will be reused by VM for other guest systems. The interface
451 allows an external monitor to balance memory of many systems.
452 Everybody who wants to run Linux under VM should select this
456 bool "/proc interface to cooperative memory management"
459 Select this option to enable the /proc interface to the
460 cooperative memory management.
463 bool "IUCV special message interface to cooperative memory management"
464 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
466 Select this option to enable the special message interface to
467 the cooperative memory management.
470 bool "Unused page notification"
472 This enables the notification of unused pages to the
473 hypervisor. The ESSA instruction is used to do the states
474 changes between a page that has content and the unused state.
477 bool "Linux - VM Monitor Stream, base infrastructure"
480 This provides a kernel interface for creating and updating z/VM APPLDATA
481 monitor records. The monitor records are updated at certain time
482 intervals, once the timer is started.
483 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
484 i.e. enables or disables monitoring on the Linux side.
485 A custom interval value (in seconds) can be written to
486 /proc/appldata/interval.
488 Defaults are 60 seconds interval and timer off.
489 The /proc entries can also be read from, showing the current settings.
492 tristate "Monitor memory management statistics"
493 depends on APPLDATA_BASE && VM_EVENT_COUNTERS
495 This provides memory management related data to the Linux - VM Monitor
496 Stream, like paging/swapping rate, memory utilisation, etc.
497 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
498 APPLDATA monitor record, i.e. enables or disables monitoring this record
502 The /proc entry can also be read from, showing the current settings.
504 This can also be compiled as a module, which will be called
508 tristate "Monitor OS statistics"
509 depends on APPLDATA_BASE
511 This provides OS related data to the Linux - VM Monitor Stream, like
512 CPU utilisation, etc.
513 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
514 APPLDATA monitor record, i.e. enables or disables monitoring this record
518 This can also be compiled as a module, which will be called
521 config APPLDATA_NET_SUM
522 tristate "Monitor overall network statistics"
523 depends on APPLDATA_BASE
525 This provides network related data to the Linux - VM Monitor Stream,
526 currently there is only a total sum of network I/O statistics, no
528 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
529 APPLDATA monitor record, i.e. enables or disables monitoring this record
533 This can also be compiled as a module, which will be called
536 source kernel/Kconfig.hz
539 bool "s390 hypervisor file system support"
540 select SYS_HYPERVISOR
543 This is a virtual file system intended to provide accounting
544 information in an s390 hypervisor environment.
547 bool "kexec system call"
549 kexec is a system call that implements the ability to shutdown your
550 current kernel, and to start another kernel. It is like a reboot
551 but is independent of hardware/microcode support.
554 tristate "zfcpdump support"
558 Select this option if you want to build an zfcpdump enabled kernel.
559 Refer to <file:Documentation/s390/zfcpdump.txt> for more details on this.
562 bool "s390 guest support for KVM (EXPERIMENTAL)"
563 depends on 64BIT && EXPERIMENTAL
566 select VIRTIO_CONSOLE
568 Select this option if you want to run the kernel as a guest under
569 the KVM hypervisor. This will add detection for KVM as well as a
570 virtio transport. If KVM is detected, the virtio console will be
582 source "drivers/Kconfig"
586 source "arch/s390/Kconfig.debug"
588 source "security/Kconfig"
590 source "crypto/Kconfig"
594 source "arch/s390/kvm/Kconfig"