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
82 comment "Processor type and features"
84 source "kernel/time/Kconfig"
89 Select this option if you have a 64 bit IBM zSeries machine
90 and want to use the 64 bit addressing mode.
97 bool "Symmetric multi-processing support"
99 This enables support for systems with more than one CPU. If you have
100 a system with only one CPU, like most personal computers, say N. If
101 you have a system with more than one CPU, say Y.
103 If you say N here, the kernel will run on single and multiprocessor
104 machines, but will use only one CPU of a multiprocessor machine. If
105 you say Y here, the kernel will run on many, but not all,
106 singleprocessor machines. On a singleprocessor machine, the kernel
107 will run faster if you say N here.
109 See also the SMP-HOWTO available at
110 <http://www.tldp.org/docs.html#howto>.
112 Even if you don't know what to do here, say Y.
115 int "Maximum number of CPUs (2-64)"
118 default "32" if !64BIT
119 default "64" if 64BIT
121 This allows you to specify the maximum number of CPUs which this
122 kernel will support. The maximum supported value is 64 and the
123 minimum value which makes sense is 2.
125 This is purely to save memory - each supported CPU adds
126 approximately sixteen kilobytes to the kernel image.
129 bool "Support for hot-pluggable CPUs"
134 Say Y here to be able to turn CPUs off and on. CPUs
135 can be controlled through /sys/devices/system/cpu/cpu#.
136 Say N if you want to disable CPU hotplug.
139 bool "IEEE FPU emulation"
142 This option is required for IEEE compliant floating point arithmetic
143 on older S/390 machines. Say Y unless you know your machine doesn't
147 bool "Kernel support for 31 bit emulation"
149 select COMPAT_BINFMT_ELF
151 Select this option if you want to enable your system kernel to
152 handle system-calls from ELF binaries for 31 bit ESA. This option
153 (and some other stuff like libraries and such) is needed for
154 executing 31 bit applications. It is safe to say "Y".
156 config SYSVIPC_COMPAT
158 depends on COMPAT && SYSVIPC
165 config S390_SWITCH_AMODE
166 bool "Switch kernel/user addressing modes"
168 This option allows to switch the addressing modes of kernel and user
169 space. The kernel parameter switch_amode=on will enable this feature,
170 default is disabled. Enabling this (via kernel parameter) on machines
171 earlier than IBM System z9-109 EC/BC will reduce system performance.
173 Note that this option will also be selected by selecting the execute
174 protection option below. Enabling the execute protection via the
175 noexec kernel parameter will also switch the addressing modes,
176 independent of the switch_amode kernel parameter.
179 config S390_EXEC_PROTECT
180 bool "Data execute protection"
181 select S390_SWITCH_AMODE
183 This option allows to enable a buffer overflow protection for user
184 space programs and it also selects the addressing mode option above.
185 The kernel parameter noexec=on will enable this feature and also
186 switch the addressing modes, default is disabled. Enabling this (via
187 kernel parameter) on machines earlier than IBM System z9-109 EC/BC
188 will reduce system performance.
190 comment "Code generation options"
193 prompt "Processor type"
197 bool "S/390 model G5 and G6"
200 Select this to build a 31 bit kernel that works
201 on all S/390 and zSeries machines.
204 bool "IBM eServer zSeries model z800 and z900"
206 Select this to optimize for zSeries machines. This
207 will enable some optimizations that are not available
208 on older 31 bit only CPUs.
211 bool "IBM eServer zSeries model z890 and z990"
213 Select this enable optimizations for model z890/z990.
214 This will be slightly faster but does not work on
215 older machines such as the z900.
220 Select this to enable optimizations for IBM System z9-109, IBM
221 System z9 Enterprise Class (z9 EC), and IBM System z9 Business
222 Class (z9 BC). The kernel will be slightly faster but will not
223 work on older machines such as the z990, z890, z900, and z800.
228 bool "Pack kernel stack"
230 This option enables the compiler option -mkernel-backchain if it
231 is available. If the option is available the compiler supports
232 the new stack layout which dramatically reduces the minimum stack
233 frame size. With an old compiler a non-leaf function needs a
234 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
235 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
236 and 24 byte on 64 bit.
238 Say Y if you are unsure.
241 bool "Use 4kb/8kb for kernel stack instead of 8kb/16kb"
242 depends on PACK_STACK && !LOCKDEP
244 If you say Y here and the compiler supports the -mkernel-backchain
245 option the kernel will use a smaller kernel stack size. For 31 bit
246 the reduced size is 4kb instead of 8kb and for 64 bit it is 8kb
247 instead of 16kb. This allows to run more thread on a system and
248 reduces the pressure on the memory management for higher order
251 Say N if you are unsure.
255 bool "Detect kernel stack overflow"
257 This option enables the compiler option -mstack-guard and
258 -mstack-size if they are available. If the compiler supports them
259 it will emit additional code to each function prolog to trigger
260 an illegal operation if the kernel stack is about to overflow.
262 Say N if you are unsure.
265 int "Size of the guard area (128-1024)"
267 depends on CHECK_STACK
270 This allows you to specify the size of the guard area at the lower
271 end of the kernel stack. If the kernel stack points into the guard
272 area on function entry an illegal operation is triggered. The size
273 needs to be a power of 2. Please keep in mind that the size of an
274 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
275 The minimum size for the stack guard should be 256 for 31 bit and
279 bool "Emit compiler warnings for function with broken stack usage"
281 This option enables the compiler options -mwarn-framesize and
282 -mwarn-dynamicstack. If the compiler supports these options it
283 will generate warnings for function which either use alloca or
284 create a stack frame bigger then CONFIG_WARN_STACK_SIZE.
286 Say N if you are unsure.
288 config WARN_STACK_SIZE
289 int "Maximum frame size considered safe (128-2048)"
291 depends on WARN_STACK
294 This allows you to specify the maximum frame size a function may
295 have without the compiler complaining about it.
297 config ARCH_POPULATES_NODE_MAP
300 comment "Kernel preemption"
302 source "kernel/Kconfig.preempt"
304 config ARCH_SPARSEMEM_ENABLE
306 select SPARSEMEM_VMEMMAP_ENABLE
307 select SPARSEMEM_VMEMMAP
308 select SPARSEMEM_STATIC if !64BIT
310 config ARCH_SPARSEMEM_DEFAULT
313 config ARCH_SELECT_MEMORY_MODEL
316 config ARCH_ENABLE_MEMORY_HOTPLUG
322 comment "I/O subsystem configuration"
324 config MACHCHK_WARNING
325 bool "Process warning machine checks"
327 Select this option if you want the machine check handler on IBM S/390 or
328 zSeries to process warning machine checks (e.g. on power failures).
332 tristate "QDIO support"
334 This driver provides the Queued Direct I/O base support for
337 To compile this driver as a module, choose M here: the
338 module will be called qdio.
343 bool "Extended debugging information"
346 Say Y here to get extended debugging output in
347 /sys/kernel/debug/s390dbf/qdio...
348 Warning: this option reduces the performance of the QDIO module.
353 tristate "Support for CHSC subchannels"
355 This driver allows usage of CHSC subchannels. A CHSC subchannel
356 is usually present on LPAR only.
357 The driver creates a device /dev/chsc, which may be used to
358 obtain I/O configuration information about the machine and
359 to issue asynchronous chsc commands (DANGEROUS).
360 You will usually only want to use this interface on a special
361 LPAR designated for system management.
363 To compile this driver as a module, choose M here: the
364 module will be called chsc_sch.
371 bool "Builtin IPL record support"
373 If you want to use the produced kernel to IPL directly from a
374 device, you have to merge a bootsector specific to the device
375 into the first bytes of the kernel. You will have to select the
379 prompt "IPL method generated into head.S"
383 Select "tape" if you want to IPL the image from a Tape.
385 Select "vm_reader" if you are running under VM/ESA and want
386 to IPL the image from the emulated card reader.
396 source "fs/Kconfig.binfmt"
398 config FORCE_MAX_ZONEORDER
403 bool "Show crashed user process info"
405 Say Y to print all process fault locations to the console. This is
406 a debugging option; you probably do not want to set it unless you
407 are an S390 port maintainer.
410 bool "Pseudo page fault support"
412 Select this option, if you want to use PFAULT pseudo page fault
413 handling under VM. If running native or in LPAR, this option
414 has no effect. If your VM does not support PFAULT, PAGEEX
415 pseudo page fault handling will be used.
416 Note that VM 4.2 supports PFAULT but has a bug in its
417 implementation that causes some problems.
418 Everybody who wants to run Linux under VM != VM4.2 should select
422 bool "VM shared kernel support"
424 Select this option, if you want to share the text segment of the
425 Linux kernel between different VM guests. This reduces memory
426 usage with lots of guests but greatly increases kernel size.
427 Also if a kernel was IPL'ed from a shared segment the kexec system
429 You should only select this option if you know what you are
430 doing and want to exploit this feature.
433 tristate "Cooperative memory management"
435 Select this option, if you want to enable the kernel interface
436 to reduce the memory size of the system. This is accomplished
437 by allocating pages of memory and put them "on hold". This only
438 makes sense for a system running under VM where the unused pages
439 will be reused by VM for other guest systems. The interface
440 allows an external monitor to balance memory of many systems.
441 Everybody who wants to run Linux under VM should select this
445 bool "/proc interface to cooperative memory management"
448 Select this option to enable the /proc interface to the
449 cooperative memory management.
452 bool "IUCV special message interface to cooperative memory management"
453 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
455 Select this option to enable the special message interface to
456 the cooperative memory management.
459 bool "Unused page notification"
461 This enables the notification of unused pages to the
462 hypervisor. The ESSA instruction is used to do the states
463 changes between a page that has content and the unused state.
466 bool "Virtual CPU timer support"
468 This provides a kernel interface for virtual CPU timers.
471 config VIRT_CPU_ACCOUNTING
472 bool "Base user process accounting on virtual cpu timer"
473 depends on VIRT_TIMER
475 Select this option to use CPU timer deltas to do user
479 bool "Linux - VM Monitor Stream, base infrastructure"
480 depends on PROC_FS && VIRT_TIMER=y
482 This provides a kernel interface for creating and updating z/VM APPLDATA
483 monitor records. The monitor records are updated at certain time
484 intervals, once the timer is started.
485 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
486 i.e. enables or disables monitoring on the Linux side.
487 A custom interval value (in seconds) can be written to
488 /proc/appldata/interval.
490 Defaults are 60 seconds interval and timer off.
491 The /proc entries can also be read from, showing the current settings.
494 tristate "Monitor memory management statistics"
495 depends on APPLDATA_BASE && VM_EVENT_COUNTERS
497 This provides memory management related data to the Linux - VM Monitor
498 Stream, like paging/swapping rate, memory utilisation, etc.
499 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
500 APPLDATA monitor record, i.e. enables or disables monitoring this record
504 The /proc entry can also be read from, showing the current settings.
506 This can also be compiled as a module, which will be called
510 tristate "Monitor OS statistics"
511 depends on APPLDATA_BASE
513 This provides OS related data to the Linux - VM Monitor Stream, like
514 CPU utilisation, etc.
515 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
516 APPLDATA monitor record, i.e. enables or disables monitoring this record
520 This can also be compiled as a module, which will be called
523 config APPLDATA_NET_SUM
524 tristate "Monitor overall network statistics"
525 depends on APPLDATA_BASE
527 This provides network related data to the Linux - VM Monitor Stream,
528 currently there is only a total sum of network I/O statistics, no
530 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
531 APPLDATA monitor record, i.e. enables or disables monitoring this record
535 This can also be compiled as a module, which will be called
538 source kernel/Kconfig.hz
541 bool "s390 hypervisor file system support"
542 select SYS_HYPERVISOR
545 This is a virtual file system intended to provide accounting
546 information in an s390 hypervisor environment.
549 bool "kexec system call"
551 kexec is a system call that implements the ability to shutdown your
552 current kernel, and to start another kernel. It is like a reboot
553 but is independent of hardware/microcode support.
556 tristate "zfcpdump support"
560 Select this option if you want to build an zfcpdump enabled kernel.
561 Refer to <file:Documentation/s390/zfcpdump.txt> for more details on this.
564 bool "s390 guest support (EXPERIMENTAL)"
565 depends on 64BIT && EXPERIMENTAL
569 Select this option if you want to run the kernel under s390 linux
580 source "drivers/Kconfig"
584 source "arch/s390/Kconfig.debug"
586 source "security/Kconfig"
588 source "crypto/Kconfig"
592 source "arch/s390/kvm/Kconfig"