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"
150 Select this option if you want to enable your system kernel to
151 handle system-calls from ELF binaries for 31 bit ESA. This option
152 (and some other stuff like libraries and such) is needed for
153 executing 31 bit applications. It is safe to say "Y".
155 config SYSVIPC_COMPAT
157 depends on COMPAT && SYSVIPC
164 config S390_SWITCH_AMODE
165 bool "Switch kernel/user addressing modes"
167 This option allows to switch the addressing modes of kernel and user
168 space. The kernel parameter switch_amode=on will enable this feature,
169 default is disabled. Enabling this (via kernel parameter) on machines
170 earlier than IBM System z9-109 EC/BC will reduce system performance.
172 Note that this option will also be selected by selecting the execute
173 protection option below. Enabling the execute protection via the
174 noexec kernel parameter will also switch the addressing modes,
175 independent of the switch_amode kernel parameter.
178 config S390_EXEC_PROTECT
179 bool "Data execute protection"
180 select S390_SWITCH_AMODE
182 This option allows to enable a buffer overflow protection for user
183 space programs and it also selects the addressing mode option above.
184 The kernel parameter noexec=on will enable this feature and also
185 switch the addressing modes, default is disabled. Enabling this (via
186 kernel parameter) on machines earlier than IBM System z9-109 EC/BC
187 will reduce system performance.
189 comment "Code generation options"
192 prompt "Processor type"
196 bool "S/390 model G5 and G6"
199 Select this to build a 31 bit kernel that works
200 on all S/390 and zSeries machines.
203 bool "IBM eServer zSeries model z800 and z900"
205 Select this to optimize for zSeries machines. This
206 will enable some optimizations that are not available
207 on older 31 bit only CPUs.
210 bool "IBM eServer zSeries model z890 and z990"
212 Select this enable optimizations for model z890/z990.
213 This will be slightly faster but does not work on
214 older machines such as the z900.
219 Select this to enable optimizations for IBM System z9-109, IBM
220 System z9 Enterprise Class (z9 EC), and IBM System z9 Business
221 Class (z9 BC). The kernel will be slightly faster but will not
222 work on older machines such as the z990, z890, z900, and z800.
227 bool "Pack kernel stack"
229 This option enables the compiler option -mkernel-backchain if it
230 is available. If the option is available the compiler supports
231 the new stack layout which dramatically reduces the minimum stack
232 frame size. With an old compiler a non-leaf function needs a
233 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
234 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
235 and 24 byte on 64 bit.
237 Say Y if you are unsure.
240 bool "Use 4kb/8kb for kernel stack instead of 8kb/16kb"
241 depends on PACK_STACK && !LOCKDEP
243 If you say Y here and the compiler supports the -mkernel-backchain
244 option the kernel will use a smaller kernel stack size. For 31 bit
245 the reduced size is 4kb instead of 8kb and for 64 bit it is 8kb
246 instead of 16kb. This allows to run more thread on a system and
247 reduces the pressure on the memory management for higher order
250 Say N if you are unsure.
254 bool "Detect kernel stack overflow"
256 This option enables the compiler option -mstack-guard and
257 -mstack-size if they are available. If the compiler supports them
258 it will emit additional code to each function prolog to trigger
259 an illegal operation if the kernel stack is about to overflow.
261 Say N if you are unsure.
264 int "Size of the guard area (128-1024)"
266 depends on CHECK_STACK
269 This allows you to specify the size of the guard area at the lower
270 end of the kernel stack. If the kernel stack points into the guard
271 area on function entry an illegal operation is triggered. The size
272 needs to be a power of 2. Please keep in mind that the size of an
273 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
274 The minimum size for the stack guard should be 256 for 31 bit and
278 bool "Emit compiler warnings for function with broken stack usage"
280 This option enables the compiler options -mwarn-framesize and
281 -mwarn-dynamicstack. If the compiler supports these options it
282 will generate warnings for function which either use alloca or
283 create a stack frame bigger then CONFIG_WARN_STACK_SIZE.
285 Say N if you are unsure.
287 config WARN_STACK_SIZE
288 int "Maximum frame size considered safe (128-2048)"
290 depends on WARN_STACK
293 This allows you to specify the maximum frame size a function may
294 have without the compiler complaining about it.
296 config ARCH_POPULATES_NODE_MAP
299 comment "Kernel preemption"
301 source "kernel/Kconfig.preempt"
305 comment "I/O subsystem configuration"
307 config MACHCHK_WARNING
308 bool "Process warning machine checks"
310 Select this option if you want the machine check handler on IBM S/390 or
311 zSeries to process warning machine checks (e.g. on power failures).
315 tristate "QDIO support"
317 This driver provides the Queued Direct I/O base support for
320 To compile this driver as a module, choose M here: the
321 module will be called qdio.
326 bool "Extended debugging information"
329 Say Y here to get extended debugging output in
330 /sys/kernel/debug/s390dbf/qdio...
331 Warning: this option reduces the performance of the QDIO module.
338 bool "Builtin IPL record support"
340 If you want to use the produced kernel to IPL directly from a
341 device, you have to merge a bootsector specific to the device
342 into the first bytes of the kernel. You will have to select the
346 prompt "IPL method generated into head.S"
350 Select "tape" if you want to IPL the image from a Tape.
352 Select "vm_reader" if you are running under VM/ESA and want
353 to IPL the image from the emulated card reader.
363 source "fs/Kconfig.binfmt"
365 config FORCE_MAX_ZONEORDER
370 bool "Show crashed user process info"
372 Say Y to print all process fault locations to the console. This is
373 a debugging option; you probably do not want to set it unless you
374 are an S390 port maintainer.
377 bool "Pseudo page fault support"
379 Select this option, if you want to use PFAULT pseudo page fault
380 handling under VM. If running native or in LPAR, this option
381 has no effect. If your VM does not support PFAULT, PAGEEX
382 pseudo page fault handling will be used.
383 Note that VM 4.2 supports PFAULT but has a bug in its
384 implementation that causes some problems.
385 Everybody who wants to run Linux under VM != VM4.2 should select
389 bool "VM shared kernel support"
391 Select this option, if you want to share the text segment of the
392 Linux kernel between different VM guests. This reduces memory
393 usage with lots of guests but greatly increases kernel size.
394 Also if a kernel was IPL'ed from a shared segment the kexec system
396 You should only select this option if you know what you are
397 doing and want to exploit this feature.
400 tristate "Cooperative memory management"
402 Select this option, if you want to enable the kernel interface
403 to reduce the memory size of the system. This is accomplished
404 by allocating pages of memory and put them "on hold". This only
405 makes sense for a system running under VM where the unused pages
406 will be reused by VM for other guest systems. The interface
407 allows an external monitor to balance memory of many systems.
408 Everybody who wants to run Linux under VM should select this
412 bool "/proc interface to cooperative memory management"
415 Select this option to enable the /proc interface to the
416 cooperative memory management.
419 bool "IUCV special message interface to cooperative memory management"
420 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
422 Select this option to enable the special message interface to
423 the cooperative memory management.
426 bool "Virtual CPU timer support"
428 This provides a kernel interface for virtual CPU timers.
431 config VIRT_CPU_ACCOUNTING
432 bool "Base user process accounting on virtual cpu timer"
433 depends on VIRT_TIMER
435 Select this option to use CPU timer deltas to do user
439 bool "Linux - VM Monitor Stream, base infrastructure"
440 depends on PROC_FS && VIRT_TIMER=y
442 This provides a kernel interface for creating and updating z/VM APPLDATA
443 monitor records. The monitor records are updated at certain time
444 intervals, once the timer is started.
445 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
446 i.e. enables or disables monitoring on the Linux side.
447 A custom interval value (in seconds) can be written to
448 /proc/appldata/interval.
450 Defaults are 60 seconds interval and timer off.
451 The /proc entries can also be read from, showing the current settings.
454 tristate "Monitor memory management statistics"
455 depends on APPLDATA_BASE && VM_EVENT_COUNTERS
457 This provides memory management related data to the Linux - VM Monitor
458 Stream, like paging/swapping rate, memory utilisation, etc.
459 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
460 APPLDATA monitor record, i.e. enables or disables monitoring this record
464 The /proc entry can also be read from, showing the current settings.
466 This can also be compiled as a module, which will be called
470 tristate "Monitor OS statistics"
471 depends on APPLDATA_BASE
473 This provides OS related data to the Linux - VM Monitor Stream, like
474 CPU utilisation, etc.
475 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
476 APPLDATA monitor record, i.e. enables or disables monitoring this record
480 This can also be compiled as a module, which will be called
483 config APPLDATA_NET_SUM
484 tristate "Monitor overall network statistics"
485 depends on APPLDATA_BASE
487 This provides network related data to the Linux - VM Monitor Stream,
488 currently there is only a total sum of network I/O statistics, no
490 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
491 APPLDATA monitor record, i.e. enables or disables monitoring this record
495 This can also be compiled as a module, which will be called
498 source kernel/Kconfig.hz
501 bool "s390 hypervisor file system support"
502 select SYS_HYPERVISOR
505 This is a virtual file system intended to provide accounting
506 information in an s390 hypervisor environment.
509 bool "kexec system call"
511 kexec is a system call that implements the ability to shutdown your
512 current kernel, and to start another kernel. It is like a reboot
513 but is independent of hardware/microcode support.
516 tristate "zfcpdump support"
520 Select this option if you want to build an zfcpdump enabled kernel.
521 Refer to <file:Documentation/s390/zfcpdump.txt> for more details on this.
524 bool "s390 guest support (EXPERIMENTAL)"
525 depends on 64BIT && EXPERIMENTAL
529 Select this option if you want to run the kernel under s390 linux
540 source "drivers/Kconfig"
544 source "arch/s390/Kconfig.debug"
546 source "security/Kconfig"
548 source "crypto/Kconfig"
552 source "arch/s390/kvm/Kconfig"