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 mainmenu "Linux Kernel Configuration"
76 select USE_GENERIC_SMP_HELPERS if SMP
79 select HAVE_KRETPROBES
80 select HAVE_KVM if 64BIT
81 select HAVE_ARCH_TRACEHOOK
85 source "kernel/Kconfig.freezer"
89 comment "Processor type and features"
91 source "kernel/time/Kconfig"
96 Select this option if you have a 64 bit IBM zSeries machine
97 and want to use the 64 bit addressing mode.
104 bool "Symmetric multi-processing support"
106 This enables support for systems with more than one CPU. If you have
107 a system with only one CPU, like most personal computers, say N. If
108 you have a system with more than one CPU, say Y.
110 If you say N here, the kernel will run on single and multiprocessor
111 machines, but will use only one CPU of a multiprocessor machine. If
112 you say Y here, the kernel will run on many, but not all,
113 singleprocessor machines. On a singleprocessor machine, the kernel
114 will run faster if you say N here.
116 See also the SMP-HOWTO available at
117 <http://www.tldp.org/docs.html#howto>.
119 Even if you don't know what to do here, say Y.
122 int "Maximum number of CPUs (2-64)"
125 default "32" if !64BIT
126 default "64" if 64BIT
128 This allows you to specify the maximum number of CPUs which this
129 kernel will support. The maximum supported value is 64 and the
130 minimum value which makes sense is 2.
132 This is purely to save memory - each supported CPU adds
133 approximately sixteen kilobytes to the kernel image.
136 bool "Support for hot-pluggable CPUs"
141 Say Y here to be able to turn CPUs off and on. CPUs
142 can be controlled through /sys/devices/system/cpu/cpu#.
143 Say N if you want to disable CPU hotplug.
146 bool "IEEE FPU emulation"
149 This option is required for IEEE compliant floating point arithmetic
150 on older S/390 machines. Say Y unless you know your machine doesn't
154 bool "Kernel support for 31 bit emulation"
156 select COMPAT_BINFMT_ELF
158 Select this option if you want to enable your system kernel to
159 handle system-calls from ELF binaries for 31 bit ESA. This option
160 (and some other stuff like libraries and such) is needed for
161 executing 31 bit applications. It is safe to say "Y".
163 config SYSVIPC_COMPAT
165 depends on COMPAT && SYSVIPC
172 config S390_SWITCH_AMODE
173 bool "Switch kernel/user addressing modes"
175 This option allows to switch the addressing modes of kernel and user
176 space. The kernel parameter switch_amode=on will enable this feature,
177 default is disabled. Enabling this (via kernel parameter) on machines
178 earlier than IBM System z9-109 EC/BC will reduce system performance.
180 Note that this option will also be selected by selecting the execute
181 protection option below. Enabling the execute protection via the
182 noexec kernel parameter will also switch the addressing modes,
183 independent of the switch_amode kernel parameter.
186 config S390_EXEC_PROTECT
187 bool "Data execute protection"
188 select S390_SWITCH_AMODE
190 This option allows to enable a buffer overflow protection for user
191 space programs and it also selects the addressing mode option above.
192 The kernel parameter noexec=on will enable this feature and also
193 switch the addressing modes, default is disabled. Enabling this (via
194 kernel parameter) on machines earlier than IBM System z9-109 EC/BC
195 will reduce system performance.
197 comment "Code generation options"
200 prompt "Processor type"
204 bool "S/390 model G5 and G6"
207 Select this to build a 31 bit kernel that works
208 on all S/390 and zSeries machines.
211 bool "IBM eServer zSeries model z800 and z900"
213 Select this to optimize for zSeries machines. This
214 will enable some optimizations that are not available
215 on older 31 bit only CPUs.
218 bool "IBM eServer zSeries model z890 and z990"
220 Select this enable optimizations for model z890/z990.
221 This will be slightly faster but does not work on
222 older machines such as the z900.
227 Select this to enable optimizations for IBM System z9-109, IBM
228 System z9 Enterprise Class (z9 EC), and IBM System z9 Business
229 Class (z9 BC). The kernel will be slightly faster but will not
230 work on older machines such as the z990, z890, z900, and z800.
235 bool "Pack kernel stack"
237 This option enables the compiler option -mkernel-backchain if it
238 is available. If the option is available the compiler supports
239 the new stack layout which dramatically reduces the minimum stack
240 frame size. With an old compiler a non-leaf function needs a
241 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
242 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
243 and 24 byte on 64 bit.
245 Say Y if you are unsure.
248 bool "Use 8kb for kernel stack instead of 16kb"
249 depends on PACK_STACK && 64BIT && !LOCKDEP
251 If you say Y here and the compiler supports the -mkernel-backchain
252 option the kernel will use a smaller kernel stack size. The reduced
253 size is 8kb instead of 16kb. This allows to run more threads on a
254 system and reduces the pressure on the memory management for higher
255 order page allocations.
257 Say N if you are unsure.
260 bool "Detect kernel stack overflow"
262 This option enables the compiler option -mstack-guard and
263 -mstack-size if they are available. If the compiler supports them
264 it will emit additional code to each function prolog to trigger
265 an illegal operation if the kernel stack is about to overflow.
267 Say N if you are unsure.
270 int "Size of the guard area (128-1024)"
272 depends on CHECK_STACK
275 This allows you to specify the size of the guard area at the lower
276 end of the kernel stack. If the kernel stack points into the guard
277 area on function entry an illegal operation is triggered. The size
278 needs to be a power of 2. Please keep in mind that the size of an
279 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
280 The minimum size for the stack guard should be 256 for 31 bit and
284 bool "Emit compiler warnings for function with broken stack usage"
286 This option enables the compiler options -mwarn-framesize and
287 -mwarn-dynamicstack. If the compiler supports these options it
288 will generate warnings for function which either use alloca or
289 create a stack frame bigger then CONFIG_WARN_STACK_SIZE.
291 Say N if you are unsure.
293 config WARN_STACK_SIZE
294 int "Maximum frame size considered safe (128-2048)"
296 depends on WARN_STACK
299 This allows you to specify the maximum frame size a function may
300 have without the compiler complaining about it.
302 config ARCH_POPULATES_NODE_MAP
305 comment "Kernel preemption"
307 source "kernel/Kconfig.preempt"
309 config ARCH_SPARSEMEM_ENABLE
311 select SPARSEMEM_VMEMMAP_ENABLE
312 select SPARSEMEM_VMEMMAP
313 select SPARSEMEM_STATIC if !64BIT
315 config ARCH_SPARSEMEM_DEFAULT
318 config ARCH_SELECT_MEMORY_MODEL
321 config ARCH_ENABLE_MEMORY_HOTPLUG
325 config ARCH_ENABLE_MEMORY_HOTREMOVE
330 comment "I/O subsystem configuration"
332 config MACHCHK_WARNING
333 bool "Process warning machine checks"
335 Select this option if you want the machine check handler on IBM S/390 or
336 zSeries to process warning machine checks (e.g. on power failures).
340 tristate "QDIO support"
342 This driver provides the Queued Direct I/O base support for
345 To compile this driver as a module, choose M here: the
346 module will be called qdio.
351 tristate "Support for CHSC subchannels"
353 This driver allows usage of CHSC subchannels. A CHSC subchannel
354 is usually present on LPAR only.
355 The driver creates a device /dev/chsc, which may be used to
356 obtain I/O configuration information about the machine and
357 to issue asynchronous chsc commands (DANGEROUS).
358 You will usually only want to use this interface on a special
359 LPAR designated for system management.
361 To compile this driver as a module, choose M here: the
362 module will be called chsc_sch.
369 bool "Builtin IPL record support"
371 If you want to use the produced kernel to IPL directly from a
372 device, you have to merge a bootsector specific to the device
373 into the first bytes of the kernel. You will have to select the
377 prompt "IPL method generated into head.S"
381 Select "tape" if you want to IPL the image from a Tape.
383 Select "vm_reader" if you are running under VM/ESA and want
384 to IPL the image from the emulated card reader.
394 source "fs/Kconfig.binfmt"
396 config FORCE_MAX_ZONEORDER
401 bool "Show crashed user process info"
403 Say Y to print all process fault locations to the console. This is
404 a debugging option; you probably do not want to set it unless you
405 are an S390 port maintainer.
408 bool "Pseudo page fault support"
410 Select this option, if you want to use PFAULT pseudo page fault
411 handling under VM. If running native or in LPAR, this option
412 has no effect. If your VM does not support PFAULT, PAGEEX
413 pseudo page fault handling will be used.
414 Note that VM 4.2 supports PFAULT but has a bug in its
415 implementation that causes some problems.
416 Everybody who wants to run Linux under VM != VM4.2 should select
420 bool "VM shared kernel support"
422 Select this option, if you want to share the text segment of the
423 Linux kernel between different VM guests. This reduces memory
424 usage with lots of guests but greatly increases kernel size.
425 Also if a kernel was IPL'ed from a shared segment the kexec system
427 You should only select this option if you know what you are
428 doing and want to exploit this feature.
431 tristate "Cooperative memory management"
433 Select this option, if you want to enable the kernel interface
434 to reduce the memory size of the system. This is accomplished
435 by allocating pages of memory and put them "on hold". This only
436 makes sense for a system running under VM where the unused pages
437 will be reused by VM for other guest systems. The interface
438 allows an external monitor to balance memory of many systems.
439 Everybody who wants to run Linux under VM should select this
443 bool "/proc interface to cooperative memory management"
446 Select this option to enable the /proc interface to the
447 cooperative memory management.
450 bool "IUCV special message interface to cooperative memory management"
451 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
453 Select this option to enable the special message interface to
454 the cooperative memory management.
457 bool "Unused page notification"
459 This enables the notification of unused pages to the
460 hypervisor. The ESSA instruction is used to do the states
461 changes between a page that has content and the unused state.
464 bool "Virtual CPU timer support"
466 This provides a kernel interface for virtual CPU timers.
469 config VIRT_CPU_ACCOUNTING
470 bool "Base user process accounting on virtual cpu timer"
471 depends on VIRT_TIMER
473 Select this option to use CPU timer deltas to do user
477 bool "Linux - VM Monitor Stream, base infrastructure"
478 depends on PROC_FS && VIRT_TIMER=y
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"