2 # For a description of the syntax of this configuration file,
3 # see Documentation/kbuild/kconfig-language.txt.
13 config LOCKDEP_SUPPORT
16 config STACKTRACE_SUPPORT
19 config HAVE_LATENCYTOP_SUPPORT
22 config RWSEM_GENERIC_SPINLOCK
25 config RWSEM_XCHGADD_ALGORITHM
28 config ARCH_HAS_ILOG2_U32
32 config ARCH_HAS_ILOG2_U64
36 config GENERIC_HWEIGHT
53 config GENERIC_LOCKBREAK
56 depends on SMP && PREEMPT
58 mainmenu "Linux Kernel Configuration"
69 comment "Processor type and features"
74 Select this option if you have a 64 bit IBM zSeries machine
75 and want to use the 64 bit addressing mode.
82 bool "Symmetric multi-processing support"
84 This enables support for systems with more than one CPU. If you have
85 a system with only one CPU, like most personal computers, say N. If
86 you have a system with more than one CPU, say Y.
88 If you say N here, the kernel will run on single and multiprocessor
89 machines, but will use only one CPU of a multiprocessor machine. If
90 you say Y here, the kernel will run on many, but not all,
91 singleprocessor machines. On a singleprocessor machine, the kernel
92 will run faster if you say N here.
94 See also the SMP-HOWTO available at
95 <http://www.tldp.org/docs.html#howto>.
97 Even if you don't know what to do here, say Y.
100 int "Maximum number of CPUs (2-64)"
103 default "32" if !64BIT
104 default "64" if 64BIT
106 This allows you to specify the maximum number of CPUs which this
107 kernel will support. The maximum supported value is 64 and the
108 minimum value which makes sense is 2.
110 This is purely to save memory - each supported CPU adds
111 approximately sixteen kilobytes to the kernel image.
114 bool "Support for hot-pluggable CPUs"
119 Say Y here to be able to turn CPUs off and on. CPUs
120 can be controlled through /sys/devices/system/cpu/cpu#.
121 Say N if you want to disable CPU hotplug.
124 bool "IEEE FPU emulation"
127 This option is required for IEEE compliant floating point arithmetic
128 on older S/390 machines. Say Y unless you know your machine doesn't
132 bool "Kernel support for 31 bit emulation"
135 Select this option if you want to enable your system kernel to
136 handle system-calls from ELF binaries for 31 bit ESA. This option
137 (and some other stuff like libraries and such) is needed for
138 executing 31 bit applications. It is safe to say "Y".
140 config SYSVIPC_COMPAT
142 depends on COMPAT && SYSVIPC
149 config S390_SWITCH_AMODE
150 bool "Switch kernel/user addressing modes"
152 This option allows to switch the addressing modes of kernel and user
153 space. The kernel parameter switch_amode=on will enable this feature,
154 default is disabled. Enabling this (via kernel parameter) on machines
155 earlier than IBM System z9-109 EC/BC will reduce system performance.
157 Note that this option will also be selected by selecting the execute
158 protection option below. Enabling the execute protection via the
159 noexec kernel parameter will also switch the addressing modes,
160 independent of the switch_amode kernel parameter.
163 config S390_EXEC_PROTECT
164 bool "Data execute protection"
165 select S390_SWITCH_AMODE
167 This option allows to enable a buffer overflow protection for user
168 space programs and it also selects the addressing mode option above.
169 The kernel parameter noexec=on will enable this feature and also
170 switch the addressing modes, default is disabled. Enabling this (via
171 kernel parameter) on machines earlier than IBM System z9-109 EC/BC
172 will reduce system performance.
174 comment "Code generation options"
177 prompt "Processor type"
181 bool "S/390 model G5 and G6"
184 Select this to build a 31 bit kernel that works
185 on all S/390 and zSeries machines.
188 bool "IBM eServer zSeries model z800 and z900"
190 Select this to optimize for zSeries machines. This
191 will enable some optimizations that are not available
192 on older 31 bit only CPUs.
195 bool "IBM eServer zSeries model z890 and z990"
197 Select this enable optimizations for model z890/z990.
198 This will be slightly faster but does not work on
199 older machines such as the z900.
204 Select this to enable optimizations for IBM System z9-109, IBM
205 System z9 Enterprise Class (z9 EC), and IBM System z9 Business
206 Class (z9 BC). The kernel will be slightly faster but will not
207 work on older machines such as the z990, z890, z900, and z800.
212 bool "Pack kernel stack"
214 This option enables the compiler option -mkernel-backchain if it
215 is available. If the option is available the compiler supports
216 the new stack layout which dramatically reduces the minimum stack
217 frame size. With an old compiler a non-leaf function needs a
218 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
219 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
220 and 24 byte on 64 bit.
222 Say Y if you are unsure.
225 bool "Use 4kb/8kb for kernel stack instead of 8kb/16kb"
226 depends on PACK_STACK && !LOCKDEP
228 If you say Y here and the compiler supports the -mkernel-backchain
229 option the kernel will use a smaller kernel stack size. For 31 bit
230 the reduced size is 4kb instead of 8kb and for 64 bit it is 8kb
231 instead of 16kb. This allows to run more thread on a system and
232 reduces the pressure on the memory management for higher order
235 Say N if you are unsure.
239 bool "Detect kernel stack overflow"
241 This option enables the compiler option -mstack-guard and
242 -mstack-size if they are available. If the compiler supports them
243 it will emit additional code to each function prolog to trigger
244 an illegal operation if the kernel stack is about to overflow.
246 Say N if you are unsure.
249 int "Size of the guard area (128-1024)"
251 depends on CHECK_STACK
254 This allows you to specify the size of the guard area at the lower
255 end of the kernel stack. If the kernel stack points into the guard
256 area on function entry an illegal operation is triggered. The size
257 needs to be a power of 2. Please keep in mind that the size of an
258 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
259 The minimum size for the stack guard should be 256 for 31 bit and
263 bool "Emit compiler warnings for function with broken stack usage"
265 This option enables the compiler options -mwarn-framesize and
266 -mwarn-dynamicstack. If the compiler supports these options it
267 will generate warnings for function which either use alloca or
268 create a stack frame bigger then CONFIG_WARN_STACK_SIZE.
270 Say N if you are unsure.
272 config WARN_STACK_SIZE
273 int "Maximum frame size considered safe (128-2048)"
275 depends on WARN_STACK
278 This allows you to specify the maximum frame size a function may
279 have without the compiler complaining about it.
281 config ARCH_POPULATES_NODE_MAP
284 comment "Kernel preemption"
286 source "kernel/Kconfig.preempt"
290 comment "I/O subsystem configuration"
292 config MACHCHK_WARNING
293 bool "Process warning machine checks"
295 Select this option if you want the machine check handler on IBM S/390 or
296 zSeries to process warning machine checks (e.g. on power failures).
300 tristate "QDIO support"
302 This driver provides the Queued Direct I/O base support for
305 For details please refer to the documentation provided by IBM at
306 <http://www10.software.ibm.com/developerworks/opensource/linux390>
308 To compile this driver as a module, choose M here: the
309 module will be called qdio.
314 bool "Extended debugging information"
317 Say Y here to get extended debugging output in
318 /sys/kernel/debug/s390dbf/qdio...
319 Warning: this option reduces the performance of the QDIO module.
326 bool "Builtin IPL record support"
328 If you want to use the produced kernel to IPL directly from a
329 device, you have to merge a bootsector specific to the device
330 into the first bytes of the kernel. You will have to select the
334 prompt "IPL method generated into head.S"
338 Select "tape" if you want to IPL the image from a Tape.
340 Select "vm_reader" if you are running under VM/ESA and want
341 to IPL the image from the emulated card reader.
351 source "fs/Kconfig.binfmt"
354 bool "Show crashed user process info"
356 Say Y to print all process fault locations to the console. This is
357 a debugging option; you probably do not want to set it unless you
358 are an S390 port maintainer.
361 bool "Pseudo page fault support"
363 Select this option, if you want to use PFAULT pseudo page fault
364 handling under VM. If running native or in LPAR, this option
365 has no effect. If your VM does not support PFAULT, PAGEEX
366 pseudo page fault handling will be used.
367 Note that VM 4.2 supports PFAULT but has a bug in its
368 implementation that causes some problems.
369 Everybody who wants to run Linux under VM != VM4.2 should select
373 bool "VM shared kernel support"
375 Select this option, if you want to share the text segment of the
376 Linux kernel between different VM guests. This reduces memory
377 usage with lots of guests but greatly increases kernel size.
378 Also if a kernel was IPL'ed from a shared segment the kexec system
380 You should only select this option if you know what you are
381 doing and want to exploit this feature.
384 tristate "Cooperative memory management"
386 Select this option, if you want to enable the kernel interface
387 to reduce the memory size of the system. This is accomplished
388 by allocating pages of memory and put them "on hold". This only
389 makes sense for a system running under VM where the unused pages
390 will be reused by VM for other guest systems. The interface
391 allows an external monitor to balance memory of many systems.
392 Everybody who wants to run Linux under VM should select this
396 bool "/proc interface to cooperative memory management"
399 Select this option to enable the /proc interface to the
400 cooperative memory management.
403 bool "IUCV special message interface to cooperative memory management"
404 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
406 Select this option to enable the special message interface to
407 the cooperative memory management.
410 bool "Virtual CPU timer support"
412 This provides a kernel interface for virtual CPU timers.
415 config VIRT_CPU_ACCOUNTING
416 bool "Base user process accounting on virtual cpu timer"
417 depends on VIRT_TIMER
419 Select this option to use CPU timer deltas to do user
423 bool "Linux - VM Monitor Stream, base infrastructure"
424 depends on PROC_FS && VIRT_TIMER=y
426 This provides a kernel interface for creating and updating z/VM APPLDATA
427 monitor records. The monitor records are updated at certain time
428 intervals, once the timer is started.
429 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
430 i.e. enables or disables monitoring on the Linux side.
431 A custom interval value (in seconds) can be written to
432 /proc/appldata/interval.
434 Defaults are 60 seconds interval and timer off.
435 The /proc entries can also be read from, showing the current settings.
438 tristate "Monitor memory management statistics"
439 depends on APPLDATA_BASE && VM_EVENT_COUNTERS
441 This provides memory management related data to the Linux - VM Monitor
442 Stream, like paging/swapping rate, memory utilisation, etc.
443 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
444 APPLDATA monitor record, i.e. enables or disables monitoring this record
448 The /proc entry can also be read from, showing the current settings.
450 This can also be compiled as a module, which will be called
454 tristate "Monitor OS statistics"
455 depends on APPLDATA_BASE
457 This provides OS related data to the Linux - VM Monitor Stream, like
458 CPU utilisation, etc.
459 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
460 APPLDATA monitor record, i.e. enables or disables monitoring this record
464 This can also be compiled as a module, which will be called
467 config APPLDATA_NET_SUM
468 tristate "Monitor overall network statistics"
469 depends on APPLDATA_BASE
471 This provides network related data to the Linux - VM Monitor Stream,
472 currently there is only a total sum of network I/O statistics, no
474 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
475 APPLDATA monitor record, i.e. enables or disables monitoring this record
479 This can also be compiled as a module, which will be called
482 source kernel/Kconfig.hz
485 bool "No HZ timer ticks in idle"
487 Switches the regular HZ timer off when the system is going idle.
488 This helps z/VM to detect that the Linux system is idle. VM can
489 then "swap-out" this guest which reduces memory usage. It also
490 reduces the overhead of idle systems.
492 The HZ timer can be switched on/off via /proc/sys/kernel/hz_timer.
493 hz_timer=0 means HZ timer is disabled. hz_timer=1 means HZ
496 config NO_IDLE_HZ_INIT
497 bool "HZ timer in idle off by default"
498 depends on NO_IDLE_HZ
500 The HZ timer is switched off in idle by default. That means the
501 HZ timer is already disabled at boot time.
504 bool "s390 hypervisor file system support"
505 select SYS_HYPERVISOR
508 This is a virtual file system intended to provide accounting
509 information in an s390 hypervisor environment.
512 bool "kexec system call"
514 kexec is a system call that implements the ability to shutdown your
515 current kernel, and to start another kernel. It is like a reboot
516 but is independent of hardware/microcode support.
519 tristate "zfcpdump support"
523 Select this option if you want to build an zfcpdump enabled kernel.
524 Refer to <file:Documentation/s390/zfcpdump.txt> for more details on this.
536 source "drivers/Kconfig"
540 source "arch/s390/Kconfig.debug"
542 source "security/Kconfig"
544 source "crypto/Kconfig"