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_FUNCTION_TRACE_MCOUNT_TEST
86 select HAVE_FTRACE_MCOUNT_RECORD
87 select HAVE_DYNAMIC_FTRACE
88 select HAVE_FUNCTION_GRAPH_TRACER
89 select HAVE_DEFAULT_NO_SPIN_MUTEXES
92 select HAVE_KRETPROBES
93 select HAVE_KVM if 64BIT
94 select HAVE_ARCH_TRACEHOOK
95 select INIT_ALL_POSSIBLE
99 source "kernel/Kconfig.freezer"
103 comment "Processor type and features"
105 source "kernel/time/Kconfig"
110 Select this option if you have a 64 bit IBM zSeries machine
111 and want to use the 64 bit addressing mode.
118 bool "Symmetric multi-processing support"
120 This enables support for systems with more than one CPU. If you have
121 a system with only one CPU, like most personal computers, say N. If
122 you have a system with more than one CPU, say Y.
124 If you say N here, the kernel will run on single and multiprocessor
125 machines, but will use only one CPU of a multiprocessor machine. If
126 you say Y here, the kernel will run on many, but not all,
127 singleprocessor machines. On a singleprocessor machine, the kernel
128 will run faster if you say N here.
130 See also the SMP-HOWTO available at
131 <http://www.tldp.org/docs.html#howto>.
133 Even if you don't know what to do here, say Y.
136 int "Maximum number of CPUs (2-64)"
139 default "32" if !64BIT
140 default "64" if 64BIT
142 This allows you to specify the maximum number of CPUs which this
143 kernel will support. The maximum supported value is 64 and the
144 minimum value which makes sense is 2.
146 This is purely to save memory - each supported CPU adds
147 approximately sixteen kilobytes to the kernel image.
150 bool "Support for hot-pluggable CPUs"
155 Say Y here to be able to turn CPUs off and on. CPUs
156 can be controlled through /sys/devices/system/cpu/cpu#.
157 Say N if you want to disable CPU hotplug.
160 bool "IEEE FPU emulation"
163 This option is required for IEEE compliant floating point arithmetic
164 on older S/390 machines. Say Y unless you know your machine doesn't
168 bool "Kernel support for 31 bit emulation"
170 select COMPAT_BINFMT_ELF
172 Select this option if you want to enable your system kernel to
173 handle system-calls from ELF binaries for 31 bit ESA. This option
174 (and some other stuff like libraries and such) is needed for
175 executing 31 bit applications. It is safe to say "Y".
177 config SYSVIPC_COMPAT
179 depends on COMPAT && SYSVIPC
186 config S390_SWITCH_AMODE
187 bool "Switch kernel/user addressing modes"
189 This option allows to switch the addressing modes of kernel and user
190 space. The kernel parameter switch_amode=on will enable this feature,
191 default is disabled. Enabling this (via kernel parameter) on machines
192 earlier than IBM System z9-109 EC/BC will reduce system performance.
194 Note that this option will also be selected by selecting the execute
195 protection option below. Enabling the execute protection via the
196 noexec kernel parameter will also switch the addressing modes,
197 independent of the switch_amode kernel parameter.
200 config S390_EXEC_PROTECT
201 bool "Data execute protection"
202 select S390_SWITCH_AMODE
204 This option allows to enable a buffer overflow protection for user
205 space programs and it also selects the addressing mode option above.
206 The kernel parameter noexec=on will enable this feature and also
207 switch the addressing modes, default is disabled. Enabling this (via
208 kernel parameter) on machines earlier than IBM System z9-109 EC/BC
209 will reduce system performance.
211 comment "Code generation options"
214 prompt "Processor type"
218 bool "S/390 model G5 and G6"
221 Select this to build a 31 bit kernel that works
222 on all S/390 and zSeries machines.
225 bool "IBM eServer zSeries model z800 and z900"
227 Select this to optimize for zSeries machines. This
228 will enable some optimizations that are not available
229 on older 31 bit only CPUs.
232 bool "IBM eServer zSeries model z890 and z990"
234 Select this enable optimizations for model z890/z990.
235 This will be slightly faster but does not work on
236 older machines such as the z900.
241 Select this to enable optimizations for IBM System z9-109, IBM
242 System z9 Enterprise Class (z9 EC), and IBM System z9 Business
243 Class (z9 BC). The kernel will be slightly faster but will not
244 work on older machines such as the z990, z890, z900, and z800.
247 bool "IBM System z10"
249 Select this to enable optimizations for IBM System z10. The
250 kernel will be slightly faster but will not work on older
251 machines such as the z990, z890, z900, z800, z9-109, z9-ec
257 bool "Pack kernel stack"
259 This option enables the compiler option -mkernel-backchain if it
260 is available. If the option is available the compiler supports
261 the new stack layout which dramatically reduces the minimum stack
262 frame size. With an old compiler a non-leaf function needs a
263 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
264 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
265 and 24 byte on 64 bit.
267 Say Y if you are unsure.
270 bool "Use 8kb for kernel stack instead of 16kb"
271 depends on PACK_STACK && 64BIT && !LOCKDEP
273 If you say Y here and the compiler supports the -mkernel-backchain
274 option the kernel will use a smaller kernel stack size. The reduced
275 size is 8kb instead of 16kb. This allows to run more threads on a
276 system and reduces the pressure on the memory management for higher
277 order page allocations.
279 Say N if you are unsure.
282 bool "Detect kernel stack overflow"
284 This option enables the compiler option -mstack-guard and
285 -mstack-size if they are available. If the compiler supports them
286 it will emit additional code to each function prolog to trigger
287 an illegal operation if the kernel stack is about to overflow.
289 Say N if you are unsure.
292 int "Size of the guard area (128-1024)"
294 depends on CHECK_STACK
297 This allows you to specify the size of the guard area at the lower
298 end of the kernel stack. If the kernel stack points into the guard
299 area on function entry an illegal operation is triggered. The size
300 needs to be a power of 2. Please keep in mind that the size of an
301 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
302 The minimum size for the stack guard should be 256 for 31 bit and
306 bool "Emit compiler warnings for function with broken stack usage"
308 This option enables the compiler options -mwarn-framesize and
309 -mwarn-dynamicstack. If the compiler supports these options it
310 will generate warnings for function which either use alloca or
311 create a stack frame bigger than CONFIG_WARN_STACK_SIZE.
313 Say N if you are unsure.
315 config WARN_STACK_SIZE
316 int "Maximum frame size considered safe (128-2048)"
318 depends on WARN_STACK
321 This allows you to specify the maximum frame size a function may
322 have without the compiler complaining about it.
324 config ARCH_POPULATES_NODE_MAP
327 comment "Kernel preemption"
329 source "kernel/Kconfig.preempt"
331 config ARCH_SPARSEMEM_ENABLE
333 select SPARSEMEM_VMEMMAP_ENABLE
334 select SPARSEMEM_VMEMMAP
335 select SPARSEMEM_STATIC if !64BIT
337 config ARCH_SPARSEMEM_DEFAULT
340 config ARCH_SELECT_MEMORY_MODEL
343 config ARCH_ENABLE_MEMORY_HOTPLUG
347 config ARCH_ENABLE_MEMORY_HOTREMOVE
352 comment "I/O subsystem configuration"
355 tristate "QDIO support"
357 This driver provides the Queued Direct I/O base support for
360 To compile this driver as a module, choose M here: the
361 module will be called qdio.
366 tristate "Support for CHSC subchannels"
368 This driver allows usage of CHSC subchannels. A CHSC subchannel
369 is usually present on LPAR only.
370 The driver creates a device /dev/chsc, which may be used to
371 obtain I/O configuration information about the machine and
372 to issue asynchronous chsc commands (DANGEROUS).
373 You will usually only want to use this interface on a special
374 LPAR designated for system management.
376 To compile this driver as a module, choose M here: the
377 module will be called chsc_sch.
384 bool "Builtin IPL record support"
386 If you want to use the produced kernel to IPL directly from a
387 device, you have to merge a bootsector specific to the device
388 into the first bytes of the kernel. You will have to select the
392 prompt "IPL method generated into head.S"
396 Select "tape" if you want to IPL the image from a Tape.
398 Select "vm_reader" if you are running under VM/ESA and want
399 to IPL the image from the emulated card reader.
409 source "fs/Kconfig.binfmt"
411 config FORCE_MAX_ZONEORDER
416 bool "Show crashed user process info"
418 Say Y to print all process fault locations to the console. This is
419 a debugging option; you probably do not want to set it unless you
420 are an S390 port maintainer.
423 bool "Pseudo page fault support"
425 Select this option, if you want to use PFAULT pseudo page fault
426 handling under VM. If running native or in LPAR, this option
427 has no effect. If your VM does not support PFAULT, PAGEEX
428 pseudo page fault handling will be used.
429 Note that VM 4.2 supports PFAULT but has a bug in its
430 implementation that causes some problems.
431 Everybody who wants to run Linux under VM != VM4.2 should select
435 bool "VM shared kernel support"
437 Select this option, if you want to share the text segment of the
438 Linux kernel between different VM guests. This reduces memory
439 usage with lots of guests but greatly increases kernel size.
440 Also if a kernel was IPL'ed from a shared segment the kexec system
442 You should only select this option if you know what you are
443 doing and want to exploit this feature.
446 tristate "Cooperative memory management"
448 Select this option, if you want to enable the kernel interface
449 to reduce the memory size of the system. This is accomplished
450 by allocating pages of memory and put them "on hold". This only
451 makes sense for a system running under VM where the unused pages
452 will be reused by VM for other guest systems. The interface
453 allows an external monitor to balance memory of many systems.
454 Everybody who wants to run Linux under VM should select this
458 bool "/proc interface to cooperative memory management"
461 Select this option to enable the /proc interface to the
462 cooperative memory management.
465 bool "IUCV special message interface to cooperative memory management"
466 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
468 Select this option to enable the special message interface to
469 the cooperative memory management.
472 bool "Unused page notification"
474 This enables the notification of unused pages to the
475 hypervisor. The ESSA instruction is used to do the states
476 changes between a page that has content and the unused state.
479 bool "Linux - VM Monitor Stream, base infrastructure"
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 && NET
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 bool "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 for KVM (EXPERIMENTAL)"
565 depends on 64BIT && EXPERIMENTAL
568 select VIRTIO_CONSOLE
570 Select this option if you want to run the kernel as a guest under
571 the KVM hypervisor. This will add detection for KVM as well as a
572 virtio transport. If KVM is detected, the virtio console will be
576 bool "Enable seccomp to safely compute untrusted bytecode"
580 This kernel feature is useful for number crunching applications
581 that may need to compute untrusted bytecode during their
582 execution. By using pipes or other transports made available to
583 the process as file descriptors supporting the read/write
584 syscalls, it's possible to isolate those applications in
585 their own address space using seccomp. Once seccomp is
586 enabled via /proc/<pid>/seccomp, it cannot be disabled
587 and the task is only allowed to execute a few safe syscalls
588 defined by each seccomp mode.
602 source "drivers/Kconfig"
606 source "arch/s390/Kconfig.debug"
608 source "security/Kconfig"
610 source "crypto/Kconfig"
614 source "arch/s390/kvm/Kconfig"