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_SYSCALL_TRACEPOINTS
88 select HAVE_DYNAMIC_FTRACE
89 select HAVE_FUNCTION_GRAPH_TRACER
90 select HAVE_REGS_AND_STACK_ACCESS_API
91 select HAVE_DEFAULT_NO_SPIN_MUTEXES
94 select HAVE_KRETPROBES
95 select HAVE_KVM if 64BIT
96 select HAVE_ARCH_TRACEHOOK
97 select INIT_ALL_POSSIBLE
98 select HAVE_PERF_EVENTS
99 select ARCH_INLINE_SPIN_TRYLOCK
100 select ARCH_INLINE_SPIN_TRYLOCK_BH
101 select ARCH_INLINE_SPIN_LOCK
102 select ARCH_INLINE_SPIN_LOCK_BH
103 select ARCH_INLINE_SPIN_LOCK_IRQ
104 select ARCH_INLINE_SPIN_LOCK_IRQSAVE
105 select ARCH_INLINE_SPIN_UNLOCK
106 select ARCH_INLINE_SPIN_UNLOCK_BH
107 select ARCH_INLINE_SPIN_UNLOCK_IRQ
108 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE
109 select ARCH_INLINE_READ_TRYLOCK
110 select ARCH_INLINE_READ_LOCK
111 select ARCH_INLINE_READ_LOCK_BH
112 select ARCH_INLINE_READ_LOCK_IRQ
113 select ARCH_INLINE_READ_LOCK_IRQSAVE
114 select ARCH_INLINE_READ_UNLOCK
115 select ARCH_INLINE_READ_UNLOCK_BH
116 select ARCH_INLINE_READ_UNLOCK_IRQ
117 select ARCH_INLINE_READ_UNLOCK_IRQRESTORE
118 select ARCH_INLINE_WRITE_TRYLOCK
119 select ARCH_INLINE_WRITE_LOCK
120 select ARCH_INLINE_WRITE_LOCK_BH
121 select ARCH_INLINE_WRITE_LOCK_IRQ
122 select ARCH_INLINE_WRITE_LOCK_IRQSAVE
123 select ARCH_INLINE_WRITE_UNLOCK
124 select ARCH_INLINE_WRITE_UNLOCK_BH
125 select ARCH_INLINE_WRITE_UNLOCK_IRQ
126 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
128 config SCHED_OMIT_FRAME_POINTER
132 source "init/Kconfig"
134 source "kernel/Kconfig.freezer"
138 comment "Processor type and features"
140 source "kernel/time/Kconfig"
145 Select this option if you have a 64 bit IBM zSeries machine
146 and want to use the 64 bit addressing mode.
156 bool "Symmetric multi-processing support"
158 This enables support for systems with more than one CPU. If you have
159 a system with only one CPU, like most personal computers, say N. If
160 you have a system with more than one CPU, say Y.
162 If you say N here, the kernel will run on single and multiprocessor
163 machines, but will use only one CPU of a multiprocessor machine. If
164 you say Y here, the kernel will run on many, but not all,
165 singleprocessor machines. On a singleprocessor machine, the kernel
166 will run faster if you say N here.
168 See also the SMP-HOWTO available at
169 <http://www.tldp.org/docs.html#howto>.
171 Even if you don't know what to do here, say Y.
174 int "Maximum number of CPUs (2-64)"
177 default "32" if !64BIT
178 default "64" if 64BIT
180 This allows you to specify the maximum number of CPUs which this
181 kernel will support. The maximum supported value is 64 and the
182 minimum value which makes sense is 2.
184 This is purely to save memory - each supported CPU adds
185 approximately sixteen kilobytes to the kernel image.
188 bool "Support for hot-pluggable CPUs"
193 Say Y here to be able to turn CPUs off and on. CPUs
194 can be controlled through /sys/devices/system/cpu/cpu#.
195 Say N if you want to disable CPU hotplug.
198 bool "IEEE FPU emulation"
201 This option is required for IEEE compliant floating point arithmetic
202 on older S/390 machines. Say Y unless you know your machine doesn't
206 bool "Kernel support for 31 bit emulation"
208 select COMPAT_BINFMT_ELF
210 Select this option if you want to enable your system kernel to
211 handle system-calls from ELF binaries for 31 bit ESA. This option
212 (and some other stuff like libraries and such) is needed for
213 executing 31 bit applications. It is safe to say "Y".
215 config SYSVIPC_COMPAT
217 depends on COMPAT && SYSVIPC
224 config S390_EXEC_PROTECT
225 bool "Data execute protection"
227 This option allows to enable a buffer overflow protection for user
228 space programs and it also selects the addressing mode option above.
229 The kernel parameter noexec=on will enable this feature and also
230 switch the addressing modes, default is disabled. Enabling this (via
231 kernel parameter) on machines earlier than IBM System z9-109 EC/BC
232 will reduce system performance.
234 comment "Code generation options"
237 prompt "Processor type"
241 bool "S/390 model G5 and G6"
244 Select this to build a 31 bit kernel that works
245 on all S/390 and zSeries machines.
248 bool "IBM eServer zSeries model z800 and z900"
250 Select this to optimize for zSeries machines. This
251 will enable some optimizations that are not available
252 on older 31 bit only CPUs.
255 bool "IBM eServer zSeries model z890 and z990"
257 Select this enable optimizations for model z890/z990.
258 This will be slightly faster but does not work on
259 older machines such as the z900.
264 Select this to enable optimizations for IBM System z9-109, IBM
265 System z9 Enterprise Class (z9 EC), and IBM System z9 Business
266 Class (z9 BC). The kernel will be slightly faster but will not
267 work on older machines such as the z990, z890, z900, and z800.
270 bool "IBM System z10"
272 Select this to enable optimizations for IBM System z10. The
273 kernel will be slightly faster but will not work on older
274 machines such as the z990, z890, z900, z800, z9-109, z9-ec
280 bool "Pack kernel stack"
282 This option enables the compiler option -mkernel-backchain if it
283 is available. If the option is available the compiler supports
284 the new stack layout which dramatically reduces the minimum stack
285 frame size. With an old compiler a non-leaf function needs a
286 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
287 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
288 and 24 byte on 64 bit.
290 Say Y if you are unsure.
293 bool "Use 8kb for kernel stack instead of 16kb"
294 depends on PACK_STACK && 64BIT && !LOCKDEP
296 If you say Y here and the compiler supports the -mkernel-backchain
297 option the kernel will use a smaller kernel stack size. The reduced
298 size is 8kb instead of 16kb. This allows to run more threads on a
299 system and reduces the pressure on the memory management for higher
300 order page allocations.
302 Say N if you are unsure.
305 bool "Detect kernel stack overflow"
307 This option enables the compiler option -mstack-guard and
308 -mstack-size if they are available. If the compiler supports them
309 it will emit additional code to each function prolog to trigger
310 an illegal operation if the kernel stack is about to overflow.
312 Say N if you are unsure.
315 int "Size of the guard area (128-1024)"
317 depends on CHECK_STACK
320 This allows you to specify the size of the guard area at the lower
321 end of the kernel stack. If the kernel stack points into the guard
322 area on function entry an illegal operation is triggered. The size
323 needs to be a power of 2. Please keep in mind that the size of an
324 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
325 The minimum size for the stack guard should be 256 for 31 bit and
329 bool "Emit compiler warnings for function with broken stack usage"
331 This option enables the compiler options -mwarn-framesize and
332 -mwarn-dynamicstack. If the compiler supports these options it
333 will generate warnings for function which either use alloca or
334 create a stack frame bigger than CONFIG_WARN_STACK_SIZE.
336 Say N if you are unsure.
338 config WARN_STACK_SIZE
339 int "Maximum frame size considered safe (128-2048)"
341 depends on WARN_STACK
344 This allows you to specify the maximum frame size a function may
345 have without the compiler complaining about it.
347 config ARCH_POPULATES_NODE_MAP
350 comment "Kernel preemption"
352 source "kernel/Kconfig.preempt"
354 config ARCH_SPARSEMEM_ENABLE
356 select SPARSEMEM_VMEMMAP_ENABLE
357 select SPARSEMEM_VMEMMAP
358 select SPARSEMEM_STATIC if !64BIT
360 config ARCH_SPARSEMEM_DEFAULT
363 config ARCH_SELECT_MEMORY_MODEL
366 config ARCH_ENABLE_MEMORY_HOTPLUG
370 config ARCH_ENABLE_MEMORY_HOTREMOVE
373 config ARCH_HIBERNATION_POSSIBLE
378 comment "I/O subsystem configuration"
381 tristate "QDIO support"
383 This driver provides the Queued Direct I/O base support for
386 To compile this driver as a module, choose M here: the
387 module will be called qdio.
392 tristate "Support for CHSC subchannels"
394 This driver allows usage of CHSC subchannels. A CHSC subchannel
395 is usually present on LPAR only.
396 The driver creates a device /dev/chsc, which may be used to
397 obtain I/O configuration information about the machine and
398 to issue asynchronous chsc commands (DANGEROUS).
399 You will usually only want to use this interface on a special
400 LPAR designated for system management.
402 To compile this driver as a module, choose M here: the
403 module will be called chsc_sch.
410 bool "Builtin IPL record support"
412 If you want to use the produced kernel to IPL directly from a
413 device, you have to merge a bootsector specific to the device
414 into the first bytes of the kernel. You will have to select the
418 prompt "IPL method generated into head.S"
422 Select "tape" if you want to IPL the image from a Tape.
424 Select "vm_reader" if you are running under VM/ESA and want
425 to IPL the image from the emulated card reader.
435 source "fs/Kconfig.binfmt"
437 config FORCE_MAX_ZONEORDER
442 bool "Show crashed user process info"
444 Say Y to print all process fault locations to the console. This is
445 a debugging option; you probably do not want to set it unless you
446 are an S390 port maintainer.
449 bool "Pseudo page fault support"
451 Select this option, if you want to use PFAULT pseudo page fault
452 handling under VM. If running native or in LPAR, this option
453 has no effect. If your VM does not support PFAULT, PAGEEX
454 pseudo page fault handling will be used.
455 Note that VM 4.2 supports PFAULT but has a bug in its
456 implementation that causes some problems.
457 Everybody who wants to run Linux under VM != VM4.2 should select
461 bool "VM shared kernel support"
463 Select this option, if you want to share the text segment of the
464 Linux kernel between different VM guests. This reduces memory
465 usage with lots of guests but greatly increases kernel size.
466 Also if a kernel was IPL'ed from a shared segment the kexec system
468 You should only select this option if you know what you are
469 doing and want to exploit this feature.
472 tristate "Cooperative memory management"
474 Select this option, if you want to enable the kernel interface
475 to reduce the memory size of the system. This is accomplished
476 by allocating pages of memory and put them "on hold". This only
477 makes sense for a system running under VM where the unused pages
478 will be reused by VM for other guest systems. The interface
479 allows an external monitor to balance memory of many systems.
480 Everybody who wants to run Linux under VM should select this
484 bool "/proc interface to cooperative memory management"
487 Select this option to enable the /proc interface to the
488 cooperative memory management.
491 bool "IUCV special message interface to cooperative memory management"
492 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
494 Select this option to enable the special message interface to
495 the cooperative memory management.
498 bool "Linux - VM Monitor Stream, base infrastructure"
501 This provides a kernel interface for creating and updating z/VM APPLDATA
502 monitor records. The monitor records are updated at certain time
503 intervals, once the timer is started.
504 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
505 i.e. enables or disables monitoring on the Linux side.
506 A custom interval value (in seconds) can be written to
507 /proc/appldata/interval.
509 Defaults are 60 seconds interval and timer off.
510 The /proc entries can also be read from, showing the current settings.
513 tristate "Monitor memory management statistics"
514 depends on APPLDATA_BASE && VM_EVENT_COUNTERS
516 This provides memory management related data to the Linux - VM Monitor
517 Stream, like paging/swapping rate, memory utilisation, etc.
518 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
519 APPLDATA monitor record, i.e. enables or disables monitoring this record
523 The /proc entry can also be read from, showing the current settings.
525 This can also be compiled as a module, which will be called
529 tristate "Monitor OS statistics"
530 depends on APPLDATA_BASE
532 This provides OS related data to the Linux - VM Monitor Stream, like
533 CPU utilisation, etc.
534 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
535 APPLDATA monitor record, i.e. enables or disables monitoring this record
539 This can also be compiled as a module, which will be called
542 config APPLDATA_NET_SUM
543 tristate "Monitor overall network statistics"
544 depends on APPLDATA_BASE && NET
546 This provides network related data to the Linux - VM Monitor Stream,
547 currently there is only a total sum of network I/O statistics, no
549 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
550 APPLDATA monitor record, i.e. enables or disables monitoring this record
554 This can also be compiled as a module, which will be called
557 source kernel/Kconfig.hz
560 bool "s390 hypervisor file system support"
561 select SYS_HYPERVISOR
564 This is a virtual file system intended to provide accounting
565 information in an s390 hypervisor environment.
568 bool "kexec system call"
570 kexec is a system call that implements the ability to shutdown your
571 current kernel, and to start another kernel. It is like a reboot
572 but is independent of hardware/microcode support.
575 bool "zfcpdump support"
579 Select this option if you want to build an zfcpdump enabled kernel.
580 Refer to <file:Documentation/s390/zfcpdump.txt> for more details on this.
583 bool "s390 guest support for KVM (EXPERIMENTAL)"
584 depends on 64BIT && EXPERIMENTAL
587 select VIRTIO_CONSOLE
589 Select this option if you want to run the kernel as a guest under
590 the KVM hypervisor. This will add detection for KVM as well as a
591 virtio transport. If KVM is detected, the virtio console will be
595 bool "Enable seccomp to safely compute untrusted bytecode"
599 This kernel feature is useful for number crunching applications
600 that may need to compute untrusted bytecode during their
601 execution. By using pipes or other transports made available to
602 the process as file descriptors supporting the read/write
603 syscalls, it's possible to isolate those applications in
604 their own address space using seccomp. Once seccomp is
605 enabled via /proc/<pid>/seccomp, it cannot be disabled
606 and the task is only allowed to execute a few safe syscalls
607 defined by each seccomp mode.
613 menu "Power Management"
615 source "kernel/power/Kconfig"
627 source "drivers/Kconfig"
631 source "arch/s390/Kconfig.debug"
633 source "security/Kconfig"
635 source "crypto/Kconfig"
639 source "arch/s390/kvm/Kconfig"