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
43 config GENERIC_TIME_VSYSCALL
46 config GENERIC_CLOCKEVENTS
54 config GENERIC_BUG_RELATIVE_POINTERS
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 HAVE_KERNEL_GZIP
100 select HAVE_KERNEL_BZIP2
101 select HAVE_KERNEL_LZMA
102 select HAVE_KERNEL_LZO
103 select ARCH_INLINE_SPIN_TRYLOCK
104 select ARCH_INLINE_SPIN_TRYLOCK_BH
105 select ARCH_INLINE_SPIN_LOCK
106 select ARCH_INLINE_SPIN_LOCK_BH
107 select ARCH_INLINE_SPIN_LOCK_IRQ
108 select ARCH_INLINE_SPIN_LOCK_IRQSAVE
109 select ARCH_INLINE_SPIN_UNLOCK
110 select ARCH_INLINE_SPIN_UNLOCK_BH
111 select ARCH_INLINE_SPIN_UNLOCK_IRQ
112 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE
113 select ARCH_INLINE_READ_TRYLOCK
114 select ARCH_INLINE_READ_LOCK
115 select ARCH_INLINE_READ_LOCK_BH
116 select ARCH_INLINE_READ_LOCK_IRQ
117 select ARCH_INLINE_READ_LOCK_IRQSAVE
118 select ARCH_INLINE_READ_UNLOCK
119 select ARCH_INLINE_READ_UNLOCK_BH
120 select ARCH_INLINE_READ_UNLOCK_IRQ
121 select ARCH_INLINE_READ_UNLOCK_IRQRESTORE
122 select ARCH_INLINE_WRITE_TRYLOCK
123 select ARCH_INLINE_WRITE_LOCK
124 select ARCH_INLINE_WRITE_LOCK_BH
125 select ARCH_INLINE_WRITE_LOCK_IRQ
126 select ARCH_INLINE_WRITE_LOCK_IRQSAVE
127 select ARCH_INLINE_WRITE_UNLOCK
128 select ARCH_INLINE_WRITE_UNLOCK_BH
129 select ARCH_INLINE_WRITE_UNLOCK_IRQ
130 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
132 config SCHED_OMIT_FRAME_POINTER
136 source "init/Kconfig"
138 source "kernel/Kconfig.freezer"
142 comment "Processor type and features"
144 source "kernel/time/Kconfig"
149 Select this option if you have a 64 bit IBM zSeries machine
150 and want to use the 64 bit addressing mode.
160 bool "Symmetric multi-processing support"
162 This enables support for systems with more than one CPU. If you have
163 a system with only one CPU, like most personal computers, say N. If
164 you have a system with more than one CPU, say Y.
166 If you say N here, the kernel will run on single and multiprocessor
167 machines, but will use only one CPU of a multiprocessor machine. If
168 you say Y here, the kernel will run on many, but not all,
169 singleprocessor machines. On a singleprocessor machine, the kernel
170 will run faster if you say N here.
172 See also the SMP-HOWTO available at
173 <http://www.tldp.org/docs.html#howto>.
175 Even if you don't know what to do here, say Y.
178 int "Maximum number of CPUs (2-64)"
181 default "32" if !64BIT
182 default "64" if 64BIT
184 This allows you to specify the maximum number of CPUs which this
185 kernel will support. The maximum supported value is 64 and the
186 minimum value which makes sense is 2.
188 This is purely to save memory - each supported CPU adds
189 approximately sixteen kilobytes to the kernel image.
192 bool "Support for hot-pluggable CPUs"
197 Say Y here to be able to turn CPUs off and on. CPUs
198 can be controlled through /sys/devices/system/cpu/cpu#.
199 Say N if you want to disable CPU hotplug.
202 bool "Book scheduler support"
205 Book scheduler support improves the CPU scheduler's decision making
206 when dealing with machines that have several books.
209 bool "IEEE FPU emulation"
212 This option is required for IEEE compliant floating point arithmetic
213 on older S/390 machines. Say Y unless you know your machine doesn't
217 bool "Kernel support for 31 bit emulation"
219 select COMPAT_BINFMT_ELF
221 Select this option if you want to enable your system kernel to
222 handle system-calls from ELF binaries for 31 bit ESA. This option
223 (and some other stuff like libraries and such) is needed for
224 executing 31 bit applications. It is safe to say "Y".
226 config SYSVIPC_COMPAT
228 depends on COMPAT && SYSVIPC
235 config S390_EXEC_PROTECT
236 bool "Data execute protection"
238 This option allows to enable a buffer overflow protection for user
239 space programs and it also selects the addressing mode option above.
240 The kernel parameter noexec=on will enable this feature and also
241 switch the addressing modes, default is disabled. Enabling this (via
242 kernel parameter) on machines earlier than IBM System z9-109 EC/BC
243 will reduce system performance.
245 comment "Code generation options"
248 prompt "Processor type"
252 bool "S/390 model G5 and G6"
255 Select this to build a 31 bit kernel that works
256 on all S/390 and zSeries machines.
259 bool "IBM eServer zSeries model z800 and z900"
261 Select this to optimize for zSeries machines. This
262 will enable some optimizations that are not available
263 on older 31 bit only CPUs.
266 bool "IBM eServer zSeries model z890 and z990"
268 Select this enable optimizations for model z890/z990.
269 This will be slightly faster but does not work on
270 older machines such as the z900.
275 Select this to enable optimizations for IBM System z9-109, IBM
276 System z9 Enterprise Class (z9 EC), and IBM System z9 Business
277 Class (z9 BC). The kernel will be slightly faster but will not
278 work on older machines such as the z990, z890, z900, and z800.
281 bool "IBM System z10"
283 Select this to enable optimizations for IBM System z10. The
284 kernel will be slightly faster but will not work on older
285 machines such as the z990, z890, z900, z800, z9-109, z9-ec
291 bool "Pack kernel stack"
293 This option enables the compiler option -mkernel-backchain if it
294 is available. If the option is available the compiler supports
295 the new stack layout which dramatically reduces the minimum stack
296 frame size. With an old compiler a non-leaf function needs a
297 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
298 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
299 and 24 byte on 64 bit.
301 Say Y if you are unsure.
304 bool "Use 8kb for kernel stack instead of 16kb"
305 depends on PACK_STACK && 64BIT && !LOCKDEP
307 If you say Y here and the compiler supports the -mkernel-backchain
308 option the kernel will use a smaller kernel stack size. The reduced
309 size is 8kb instead of 16kb. This allows to run more threads on a
310 system and reduces the pressure on the memory management for higher
311 order page allocations.
313 Say N if you are unsure.
316 bool "Detect kernel stack overflow"
318 This option enables the compiler option -mstack-guard and
319 -mstack-size if they are available. If the compiler supports them
320 it will emit additional code to each function prolog to trigger
321 an illegal operation if the kernel stack is about to overflow.
323 Say N if you are unsure.
326 int "Size of the guard area (128-1024)"
328 depends on CHECK_STACK
331 This allows you to specify the size of the guard area at the lower
332 end of the kernel stack. If the kernel stack points into the guard
333 area on function entry an illegal operation is triggered. The size
334 needs to be a power of 2. Please keep in mind that the size of an
335 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
336 The minimum size for the stack guard should be 256 for 31 bit and
340 bool "Emit compiler warnings for function with broken stack usage"
342 This option enables the compiler options -mwarn-framesize and
343 -mwarn-dynamicstack. If the compiler supports these options it
344 will generate warnings for function which either use alloca or
345 create a stack frame bigger than CONFIG_WARN_STACK_SIZE.
347 Say N if you are unsure.
349 config WARN_STACK_SIZE
350 int "Maximum frame size considered safe (128-2048)"
352 depends on WARN_STACK
355 This allows you to specify the maximum frame size a function may
356 have without the compiler complaining about it.
358 config ARCH_POPULATES_NODE_MAP
361 comment "Kernel preemption"
363 source "kernel/Kconfig.preempt"
365 config ARCH_SPARSEMEM_ENABLE
367 select SPARSEMEM_VMEMMAP_ENABLE
368 select SPARSEMEM_VMEMMAP
369 select SPARSEMEM_STATIC if !64BIT
371 config ARCH_SPARSEMEM_DEFAULT
374 config ARCH_SELECT_MEMORY_MODEL
377 config ARCH_ENABLE_MEMORY_HOTPLUG
381 config ARCH_ENABLE_MEMORY_HOTREMOVE
384 config ARCH_HIBERNATION_POSSIBLE
389 comment "I/O subsystem configuration"
392 tristate "QDIO support"
394 This driver provides the Queued Direct I/O base support for
397 To compile this driver as a module, choose M here: the
398 module will be called qdio.
403 tristate "Support for CHSC subchannels"
405 This driver allows usage of CHSC subchannels. A CHSC subchannel
406 is usually present on LPAR only.
407 The driver creates a device /dev/chsc, which may be used to
408 obtain I/O configuration information about the machine and
409 to issue asynchronous chsc commands (DANGEROUS).
410 You will usually only want to use this interface on a special
411 LPAR designated for system management.
413 To compile this driver as a module, choose M here: the
414 module will be called chsc_sch.
421 bool "Builtin IPL record support"
423 If you want to use the produced kernel to IPL directly from a
424 device, you have to merge a bootsector specific to the device
425 into the first bytes of the kernel. You will have to select the
429 prompt "IPL method generated into head.S"
433 Select "tape" if you want to IPL the image from a Tape.
435 Select "vm_reader" if you are running under VM/ESA and want
436 to IPL the image from the emulated card reader.
446 source "fs/Kconfig.binfmt"
448 config FORCE_MAX_ZONEORDER
453 bool "Pseudo page fault support"
455 Select this option, if you want to use PFAULT pseudo page fault
456 handling under VM. If running native or in LPAR, this option
457 has no effect. If your VM does not support PFAULT, PAGEEX
458 pseudo page fault handling will be used.
459 Note that VM 4.2 supports PFAULT but has a bug in its
460 implementation that causes some problems.
461 Everybody who wants to run Linux under VM != VM4.2 should select
465 bool "VM shared kernel support"
467 Select this option, if you want to share the text segment of the
468 Linux kernel between different VM guests. This reduces memory
469 usage with lots of guests but greatly increases kernel size.
470 Also if a kernel was IPL'ed from a shared segment the kexec system
472 You should only select this option if you know what you are
473 doing and want to exploit this feature.
476 tristate "Cooperative memory management"
478 Select this option, if you want to enable the kernel interface
479 to reduce the memory size of the system. This is accomplished
480 by allocating pages of memory and put them "on hold". This only
481 makes sense for a system running under VM where the unused pages
482 will be reused by VM for other guest systems. The interface
483 allows an external monitor to balance memory of many systems.
484 Everybody who wants to run Linux under VM should select this
488 bool "IUCV special message interface to cooperative memory management"
489 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
491 Select this option to enable the special message interface to
492 the cooperative memory management.
495 bool "Linux - VM Monitor Stream, base infrastructure"
498 This provides a kernel interface for creating and updating z/VM APPLDATA
499 monitor records. The monitor records are updated at certain time
500 intervals, once the timer is started.
501 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
502 i.e. enables or disables monitoring on the Linux side.
503 A custom interval value (in seconds) can be written to
504 /proc/appldata/interval.
506 Defaults are 60 seconds interval and timer off.
507 The /proc entries can also be read from, showing the current settings.
510 tristate "Monitor memory management statistics"
511 depends on APPLDATA_BASE && VM_EVENT_COUNTERS
513 This provides memory management related data to the Linux - VM Monitor
514 Stream, like paging/swapping rate, memory utilisation, etc.
515 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
516 APPLDATA monitor record, i.e. enables or disables monitoring this record
520 The /proc entry can also be read from, showing the current settings.
522 This can also be compiled as a module, which will be called
526 tristate "Monitor OS statistics"
527 depends on APPLDATA_BASE
529 This provides OS related data to the Linux - VM Monitor Stream, like
530 CPU utilisation, etc.
531 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
532 APPLDATA monitor record, i.e. enables or disables monitoring this record
536 This can also be compiled as a module, which will be called
539 config APPLDATA_NET_SUM
540 tristate "Monitor overall network statistics"
541 depends on APPLDATA_BASE && NET
543 This provides network related data to the Linux - VM Monitor Stream,
544 currently there is only a total sum of network I/O statistics, no
546 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
547 APPLDATA monitor record, i.e. enables or disables monitoring this record
551 This can also be compiled as a module, which will be called
554 source kernel/Kconfig.hz
557 bool "s390 hypervisor file system support"
558 select SYS_HYPERVISOR
561 This is a virtual file system intended to provide accounting
562 information in an s390 hypervisor environment.
565 bool "kexec system call"
567 kexec is a system call that implements the ability to shutdown your
568 current kernel, and to start another kernel. It is like a reboot
569 but is independent of hardware/microcode support.
572 bool "zfcpdump support"
576 Select this option if you want to build an zfcpdump enabled kernel.
577 Refer to <file:Documentation/s390/zfcpdump.txt> for more details on this.
580 bool "s390 guest support for KVM (EXPERIMENTAL)"
581 depends on 64BIT && EXPERIMENTAL
584 select VIRTIO_CONSOLE
586 Select this option if you want to run the kernel as a guest under
587 the KVM hypervisor. This will add detection for KVM as well as a
588 virtio transport. If KVM is detected, the virtio console will be
592 bool "Enable seccomp to safely compute untrusted bytecode"
596 This kernel feature is useful for number crunching applications
597 that may need to compute untrusted bytecode during their
598 execution. By using pipes or other transports made available to
599 the process as file descriptors supporting the read/write
600 syscalls, it's possible to isolate those applications in
601 their own address space using seccomp. Once seccomp is
602 enabled via /proc/<pid>/seccomp, it cannot be disabled
603 and the task is only allowed to execute a few safe syscalls
604 defined by each seccomp mode.
610 menu "Power Management"
612 source "kernel/power/Kconfig"
624 source "drivers/Kconfig"
628 source "arch/s390/Kconfig.debug"
630 source "security/Kconfig"
632 source "crypto/Kconfig"
636 source "arch/s390/kvm/Kconfig"