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 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
78 mainmenu "Linux Kernel Configuration"
82 select USE_GENERIC_SMP_HELPERS if SMP
83 select HAVE_SYSCALL_WRAPPERS
84 select HAVE_FUNCTION_TRACER
85 select HAVE_DEFAULT_NO_SPIN_MUTEXES
88 select HAVE_KRETPROBES
89 select HAVE_KVM if 64BIT
90 select HAVE_ARCH_TRACEHOOK
91 select INIT_ALL_POSSIBLE
95 source "kernel/Kconfig.freezer"
99 comment "Processor type and features"
101 source "kernel/time/Kconfig"
106 Select this option if you have a 64 bit IBM zSeries machine
107 and want to use the 64 bit addressing mode.
114 bool "Symmetric multi-processing support"
116 This enables support for systems with more than one CPU. If you have
117 a system with only one CPU, like most personal computers, say N. If
118 you have a system with more than one CPU, say Y.
120 If you say N here, the kernel will run on single and multiprocessor
121 machines, but will use only one CPU of a multiprocessor machine. If
122 you say Y here, the kernel will run on many, but not all,
123 singleprocessor machines. On a singleprocessor machine, the kernel
124 will run faster if you say N here.
126 See also the SMP-HOWTO available at
127 <http://www.tldp.org/docs.html#howto>.
129 Even if you don't know what to do here, say Y.
132 int "Maximum number of CPUs (2-64)"
135 default "32" if !64BIT
136 default "64" if 64BIT
138 This allows you to specify the maximum number of CPUs which this
139 kernel will support. The maximum supported value is 64 and the
140 minimum value which makes sense is 2.
142 This is purely to save memory - each supported CPU adds
143 approximately sixteen kilobytes to the kernel image.
146 bool "Support for hot-pluggable CPUs"
151 Say Y here to be able to turn CPUs off and on. CPUs
152 can be controlled through /sys/devices/system/cpu/cpu#.
153 Say N if you want to disable CPU hotplug.
156 bool "IEEE FPU emulation"
159 This option is required for IEEE compliant floating point arithmetic
160 on older S/390 machines. Say Y unless you know your machine doesn't
164 bool "Kernel support for 31 bit emulation"
166 select COMPAT_BINFMT_ELF
168 Select this option if you want to enable your system kernel to
169 handle system-calls from ELF binaries for 31 bit ESA. This option
170 (and some other stuff like libraries and such) is needed for
171 executing 31 bit applications. It is safe to say "Y".
173 config SYSVIPC_COMPAT
175 depends on COMPAT && SYSVIPC
182 config S390_SWITCH_AMODE
183 bool "Switch kernel/user addressing modes"
185 This option allows to switch the addressing modes of kernel and user
186 space. The kernel parameter switch_amode=on will enable this feature,
187 default is disabled. Enabling this (via kernel parameter) on machines
188 earlier than IBM System z9-109 EC/BC will reduce system performance.
190 Note that this option will also be selected by selecting the execute
191 protection option below. Enabling the execute protection via the
192 noexec kernel parameter will also switch the addressing modes,
193 independent of the switch_amode kernel parameter.
196 config S390_EXEC_PROTECT
197 bool "Data execute protection"
198 select S390_SWITCH_AMODE
200 This option allows to enable a buffer overflow protection for user
201 space programs and it also selects the addressing mode option above.
202 The kernel parameter noexec=on will enable this feature and also
203 switch the addressing modes, default is disabled. Enabling this (via
204 kernel parameter) on machines earlier than IBM System z9-109 EC/BC
205 will reduce system performance.
207 comment "Code generation options"
210 prompt "Processor type"
214 bool "S/390 model G5 and G6"
217 Select this to build a 31 bit kernel that works
218 on all S/390 and zSeries machines.
221 bool "IBM eServer zSeries model z800 and z900"
223 Select this to optimize for zSeries machines. This
224 will enable some optimizations that are not available
225 on older 31 bit only CPUs.
228 bool "IBM eServer zSeries model z890 and z990"
230 Select this enable optimizations for model z890/z990.
231 This will be slightly faster but does not work on
232 older machines such as the z900.
237 Select this to enable optimizations for IBM System z9-109, IBM
238 System z9 Enterprise Class (z9 EC), and IBM System z9 Business
239 Class (z9 BC). The kernel will be slightly faster but will not
240 work on older machines such as the z990, z890, z900, and z800.
243 bool "IBM System z10"
245 Select this to enable optimizations for IBM System z10. The
246 kernel will be slightly faster but will not work on older
247 machines such as the z990, z890, z900, z800, z9-109, z9-ec
253 bool "Pack kernel stack"
255 This option enables the compiler option -mkernel-backchain if it
256 is available. If the option is available the compiler supports
257 the new stack layout which dramatically reduces the minimum stack
258 frame size. With an old compiler a non-leaf function needs a
259 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
260 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
261 and 24 byte on 64 bit.
263 Say Y if you are unsure.
266 bool "Use 8kb for kernel stack instead of 16kb"
267 depends on PACK_STACK && 64BIT && !LOCKDEP
269 If you say Y here and the compiler supports the -mkernel-backchain
270 option the kernel will use a smaller kernel stack size. The reduced
271 size is 8kb instead of 16kb. This allows to run more threads on a
272 system and reduces the pressure on the memory management for higher
273 order page allocations.
275 Say N if you are unsure.
278 bool "Detect kernel stack overflow"
280 This option enables the compiler option -mstack-guard and
281 -mstack-size if they are available. If the compiler supports them
282 it will emit additional code to each function prolog to trigger
283 an illegal operation if the kernel stack is about to overflow.
285 Say N if you are unsure.
288 int "Size of the guard area (128-1024)"
290 depends on CHECK_STACK
293 This allows you to specify the size of the guard area at the lower
294 end of the kernel stack. If the kernel stack points into the guard
295 area on function entry an illegal operation is triggered. The size
296 needs to be a power of 2. Please keep in mind that the size of an
297 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
298 The minimum size for the stack guard should be 256 for 31 bit and
302 bool "Emit compiler warnings for function with broken stack usage"
304 This option enables the compiler options -mwarn-framesize and
305 -mwarn-dynamicstack. If the compiler supports these options it
306 will generate warnings for function which either use alloca or
307 create a stack frame bigger than CONFIG_WARN_STACK_SIZE.
309 Say N if you are unsure.
311 config WARN_STACK_SIZE
312 int "Maximum frame size considered safe (128-2048)"
314 depends on WARN_STACK
317 This allows you to specify the maximum frame size a function may
318 have without the compiler complaining about it.
320 config ARCH_POPULATES_NODE_MAP
323 comment "Kernel preemption"
325 source "kernel/Kconfig.preempt"
327 config ARCH_SPARSEMEM_ENABLE
329 select SPARSEMEM_VMEMMAP_ENABLE
330 select SPARSEMEM_VMEMMAP
331 select SPARSEMEM_STATIC if !64BIT
333 config ARCH_SPARSEMEM_DEFAULT
336 config ARCH_SELECT_MEMORY_MODEL
339 config ARCH_ENABLE_MEMORY_HOTPLUG
343 config ARCH_ENABLE_MEMORY_HOTREMOVE
348 comment "I/O subsystem configuration"
351 tristate "QDIO support"
353 This driver provides the Queued Direct I/O base support for
356 To compile this driver as a module, choose M here: the
357 module will be called qdio.
362 tristate "Support for CHSC subchannels"
364 This driver allows usage of CHSC subchannels. A CHSC subchannel
365 is usually present on LPAR only.
366 The driver creates a device /dev/chsc, which may be used to
367 obtain I/O configuration information about the machine and
368 to issue asynchronous chsc commands (DANGEROUS).
369 You will usually only want to use this interface on a special
370 LPAR designated for system management.
372 To compile this driver as a module, choose M here: the
373 module will be called chsc_sch.
380 bool "Builtin IPL record support"
382 If you want to use the produced kernel to IPL directly from a
383 device, you have to merge a bootsector specific to the device
384 into the first bytes of the kernel. You will have to select the
388 prompt "IPL method generated into head.S"
392 Select "tape" if you want to IPL the image from a Tape.
394 Select "vm_reader" if you are running under VM/ESA and want
395 to IPL the image from the emulated card reader.
405 source "fs/Kconfig.binfmt"
407 config FORCE_MAX_ZONEORDER
412 bool "Show crashed user process info"
414 Say Y to print all process fault locations to the console. This is
415 a debugging option; you probably do not want to set it unless you
416 are an S390 port maintainer.
419 bool "Pseudo page fault support"
421 Select this option, if you want to use PFAULT pseudo page fault
422 handling under VM. If running native or in LPAR, this option
423 has no effect. If your VM does not support PFAULT, PAGEEX
424 pseudo page fault handling will be used.
425 Note that VM 4.2 supports PFAULT but has a bug in its
426 implementation that causes some problems.
427 Everybody who wants to run Linux under VM != VM4.2 should select
431 bool "VM shared kernel support"
433 Select this option, if you want to share the text segment of the
434 Linux kernel between different VM guests. This reduces memory
435 usage with lots of guests but greatly increases kernel size.
436 Also if a kernel was IPL'ed from a shared segment the kexec system
438 You should only select this option if you know what you are
439 doing and want to exploit this feature.
442 tristate "Cooperative memory management"
444 Select this option, if you want to enable the kernel interface
445 to reduce the memory size of the system. This is accomplished
446 by allocating pages of memory and put them "on hold". This only
447 makes sense for a system running under VM where the unused pages
448 will be reused by VM for other guest systems. The interface
449 allows an external monitor to balance memory of many systems.
450 Everybody who wants to run Linux under VM should select this
454 bool "/proc interface to cooperative memory management"
457 Select this option to enable the /proc interface to the
458 cooperative memory management.
461 bool "IUCV special message interface to cooperative memory management"
462 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
464 Select this option to enable the special message interface to
465 the cooperative memory management.
468 bool "Unused page notification"
470 This enables the notification of unused pages to the
471 hypervisor. The ESSA instruction is used to do the states
472 changes between a page that has content and the unused state.
475 bool "Linux - VM Monitor Stream, base infrastructure"
478 This provides a kernel interface for creating and updating z/VM APPLDATA
479 monitor records. The monitor records are updated at certain time
480 intervals, once the timer is started.
481 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
482 i.e. enables or disables monitoring on the Linux side.
483 A custom interval value (in seconds) can be written to
484 /proc/appldata/interval.
486 Defaults are 60 seconds interval and timer off.
487 The /proc entries can also be read from, showing the current settings.
490 tristate "Monitor memory management statistics"
491 depends on APPLDATA_BASE && VM_EVENT_COUNTERS
493 This provides memory management related data to the Linux - VM Monitor
494 Stream, like paging/swapping rate, memory utilisation, etc.
495 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
496 APPLDATA monitor record, i.e. enables or disables monitoring this record
500 The /proc entry can also be read from, showing the current settings.
502 This can also be compiled as a module, which will be called
506 tristate "Monitor OS statistics"
507 depends on APPLDATA_BASE
509 This provides OS related data to the Linux - VM Monitor Stream, like
510 CPU utilisation, etc.
511 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
512 APPLDATA monitor record, i.e. enables or disables monitoring this record
516 This can also be compiled as a module, which will be called
519 config APPLDATA_NET_SUM
520 tristate "Monitor overall network statistics"
521 depends on APPLDATA_BASE && NET
523 This provides network related data to the Linux - VM Monitor Stream,
524 currently there is only a total sum of network I/O statistics, no
526 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
527 APPLDATA monitor record, i.e. enables or disables monitoring this record
531 This can also be compiled as a module, which will be called
534 source kernel/Kconfig.hz
537 bool "s390 hypervisor file system support"
538 select SYS_HYPERVISOR
541 This is a virtual file system intended to provide accounting
542 information in an s390 hypervisor environment.
545 bool "kexec system call"
547 kexec is a system call that implements the ability to shutdown your
548 current kernel, and to start another kernel. It is like a reboot
549 but is independent of hardware/microcode support.
552 bool "zfcpdump support"
556 Select this option if you want to build an zfcpdump enabled kernel.
557 Refer to <file:Documentation/s390/zfcpdump.txt> for more details on this.
560 bool "s390 guest support for KVM (EXPERIMENTAL)"
561 depends on 64BIT && EXPERIMENTAL
564 select VIRTIO_CONSOLE
566 Select this option if you want to run the kernel as a guest under
567 the KVM hypervisor. This will add detection for KVM as well as a
568 virtio transport. If KVM is detected, the virtio console will be
580 source "drivers/Kconfig"
584 source "arch/s390/Kconfig.debug"
586 source "security/Kconfig"
588 source "crypto/Kconfig"
592 source "arch/s390/kvm/Kconfig"