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
57 config GENERIC_BUG_RELATIVE_POINTERS
66 config GENERIC_LOCKBREAK
69 depends on SMP && PREEMPT
75 config VIRT_CPU_ACCOUNTING
78 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
81 mainmenu "Linux Kernel Configuration"
85 select USE_GENERIC_SMP_HELPERS if SMP
86 select HAVE_SYSCALL_WRAPPERS
87 select HAVE_FUNCTION_TRACER
88 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
89 select HAVE_FTRACE_MCOUNT_RECORD
90 select HAVE_SYSCALL_TRACEPOINTS
91 select HAVE_DYNAMIC_FTRACE
92 select HAVE_FUNCTION_GRAPH_TRACER
93 select HAVE_REGS_AND_STACK_ACCESS_API
94 select HAVE_DEFAULT_NO_SPIN_MUTEXES
97 select HAVE_KRETPROBES
98 select HAVE_KVM if 64BIT
99 select HAVE_ARCH_TRACEHOOK
100 select INIT_ALL_POSSIBLE
101 select HAVE_PERF_EVENTS
102 select HAVE_KERNEL_GZIP
103 select HAVE_KERNEL_BZIP2
104 select HAVE_KERNEL_LZMA
105 select ARCH_INLINE_SPIN_TRYLOCK
106 select ARCH_INLINE_SPIN_TRYLOCK_BH
107 select ARCH_INLINE_SPIN_LOCK
108 select ARCH_INLINE_SPIN_LOCK_BH
109 select ARCH_INLINE_SPIN_LOCK_IRQ
110 select ARCH_INLINE_SPIN_LOCK_IRQSAVE
111 select ARCH_INLINE_SPIN_UNLOCK
112 select ARCH_INLINE_SPIN_UNLOCK_BH
113 select ARCH_INLINE_SPIN_UNLOCK_IRQ
114 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE
115 select ARCH_INLINE_READ_TRYLOCK
116 select ARCH_INLINE_READ_LOCK
117 select ARCH_INLINE_READ_LOCK_BH
118 select ARCH_INLINE_READ_LOCK_IRQ
119 select ARCH_INLINE_READ_LOCK_IRQSAVE
120 select ARCH_INLINE_READ_UNLOCK
121 select ARCH_INLINE_READ_UNLOCK_BH
122 select ARCH_INLINE_READ_UNLOCK_IRQ
123 select ARCH_INLINE_READ_UNLOCK_IRQRESTORE
124 select ARCH_INLINE_WRITE_TRYLOCK
125 select ARCH_INLINE_WRITE_LOCK
126 select ARCH_INLINE_WRITE_LOCK_BH
127 select ARCH_INLINE_WRITE_LOCK_IRQ
128 select ARCH_INLINE_WRITE_LOCK_IRQSAVE
129 select ARCH_INLINE_WRITE_UNLOCK
130 select ARCH_INLINE_WRITE_UNLOCK_BH
131 select ARCH_INLINE_WRITE_UNLOCK_IRQ
132 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
134 config SCHED_OMIT_FRAME_POINTER
138 source "init/Kconfig"
140 source "kernel/Kconfig.freezer"
144 comment "Processor type and features"
146 source "kernel/time/Kconfig"
151 Select this option if you have a 64 bit IBM zSeries machine
152 and want to use the 64 bit addressing mode.
162 bool "Symmetric multi-processing support"
164 This enables support for systems with more than one CPU. If you have
165 a system with only one CPU, like most personal computers, say N. If
166 you have a system with more than one CPU, say Y.
168 If you say N here, the kernel will run on single and multiprocessor
169 machines, but will use only one CPU of a multiprocessor machine. If
170 you say Y here, the kernel will run on many, but not all,
171 singleprocessor machines. On a singleprocessor machine, the kernel
172 will run faster if you say N here.
174 See also the SMP-HOWTO available at
175 <http://www.tldp.org/docs.html#howto>.
177 Even if you don't know what to do here, say Y.
180 int "Maximum number of CPUs (2-64)"
183 default "32" if !64BIT
184 default "64" if 64BIT
186 This allows you to specify the maximum number of CPUs which this
187 kernel will support. The maximum supported value is 64 and the
188 minimum value which makes sense is 2.
190 This is purely to save memory - each supported CPU adds
191 approximately sixteen kilobytes to the kernel image.
194 bool "Support for hot-pluggable CPUs"
199 Say Y here to be able to turn CPUs off and on. CPUs
200 can be controlled through /sys/devices/system/cpu/cpu#.
201 Say N if you want to disable CPU hotplug.
204 bool "IEEE FPU emulation"
207 This option is required for IEEE compliant floating point arithmetic
208 on older S/390 machines. Say Y unless you know your machine doesn't
212 bool "Kernel support for 31 bit emulation"
214 select COMPAT_BINFMT_ELF
216 Select this option if you want to enable your system kernel to
217 handle system-calls from ELF binaries for 31 bit ESA. This option
218 (and some other stuff like libraries and such) is needed for
219 executing 31 bit applications. It is safe to say "Y".
221 config SYSVIPC_COMPAT
223 depends on COMPAT && SYSVIPC
230 config S390_EXEC_PROTECT
231 bool "Data execute protection"
233 This option allows to enable a buffer overflow protection for user
234 space programs and it also selects the addressing mode option above.
235 The kernel parameter noexec=on will enable this feature and also
236 switch the addressing modes, default is disabled. Enabling this (via
237 kernel parameter) on machines earlier than IBM System z9-109 EC/BC
238 will reduce system performance.
240 comment "Code generation options"
243 prompt "Processor type"
247 bool "S/390 model G5 and G6"
250 Select this to build a 31 bit kernel that works
251 on all S/390 and zSeries machines.
254 bool "IBM eServer zSeries model z800 and z900"
256 Select this to optimize for zSeries machines. This
257 will enable some optimizations that are not available
258 on older 31 bit only CPUs.
261 bool "IBM eServer zSeries model z890 and z990"
263 Select this enable optimizations for model z890/z990.
264 This will be slightly faster but does not work on
265 older machines such as the z900.
270 Select this to enable optimizations for IBM System z9-109, IBM
271 System z9 Enterprise Class (z9 EC), and IBM System z9 Business
272 Class (z9 BC). The kernel will be slightly faster but will not
273 work on older machines such as the z990, z890, z900, and z800.
276 bool "IBM System z10"
278 Select this to enable optimizations for IBM System z10. The
279 kernel will be slightly faster but will not work on older
280 machines such as the z990, z890, z900, z800, z9-109, z9-ec
286 bool "Pack kernel stack"
288 This option enables the compiler option -mkernel-backchain if it
289 is available. If the option is available the compiler supports
290 the new stack layout which dramatically reduces the minimum stack
291 frame size. With an old compiler a non-leaf function needs a
292 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
293 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
294 and 24 byte on 64 bit.
296 Say Y if you are unsure.
299 bool "Use 8kb for kernel stack instead of 16kb"
300 depends on PACK_STACK && 64BIT && !LOCKDEP
302 If you say Y here and the compiler supports the -mkernel-backchain
303 option the kernel will use a smaller kernel stack size. The reduced
304 size is 8kb instead of 16kb. This allows to run more threads on a
305 system and reduces the pressure on the memory management for higher
306 order page allocations.
308 Say N if you are unsure.
311 bool "Detect kernel stack overflow"
313 This option enables the compiler option -mstack-guard and
314 -mstack-size if they are available. If the compiler supports them
315 it will emit additional code to each function prolog to trigger
316 an illegal operation if the kernel stack is about to overflow.
318 Say N if you are unsure.
321 int "Size of the guard area (128-1024)"
323 depends on CHECK_STACK
326 This allows you to specify the size of the guard area at the lower
327 end of the kernel stack. If the kernel stack points into the guard
328 area on function entry an illegal operation is triggered. The size
329 needs to be a power of 2. Please keep in mind that the size of an
330 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
331 The minimum size for the stack guard should be 256 for 31 bit and
335 bool "Emit compiler warnings for function with broken stack usage"
337 This option enables the compiler options -mwarn-framesize and
338 -mwarn-dynamicstack. If the compiler supports these options it
339 will generate warnings for function which either use alloca or
340 create a stack frame bigger than CONFIG_WARN_STACK_SIZE.
342 Say N if you are unsure.
344 config WARN_STACK_SIZE
345 int "Maximum frame size considered safe (128-2048)"
347 depends on WARN_STACK
350 This allows you to specify the maximum frame size a function may
351 have without the compiler complaining about it.
353 config ARCH_POPULATES_NODE_MAP
356 comment "Kernel preemption"
358 source "kernel/Kconfig.preempt"
360 config ARCH_SPARSEMEM_ENABLE
362 select SPARSEMEM_VMEMMAP_ENABLE
363 select SPARSEMEM_VMEMMAP
364 select SPARSEMEM_STATIC if !64BIT
366 config ARCH_SPARSEMEM_DEFAULT
369 config ARCH_SELECT_MEMORY_MODEL
372 config ARCH_ENABLE_MEMORY_HOTPLUG
376 config ARCH_ENABLE_MEMORY_HOTREMOVE
379 config ARCH_HIBERNATION_POSSIBLE
384 comment "I/O subsystem configuration"
387 tristate "QDIO support"
389 This driver provides the Queued Direct I/O base support for
392 To compile this driver as a module, choose M here: the
393 module will be called qdio.
398 tristate "Support for CHSC subchannels"
400 This driver allows usage of CHSC subchannels. A CHSC subchannel
401 is usually present on LPAR only.
402 The driver creates a device /dev/chsc, which may be used to
403 obtain I/O configuration information about the machine and
404 to issue asynchronous chsc commands (DANGEROUS).
405 You will usually only want to use this interface on a special
406 LPAR designated for system management.
408 To compile this driver as a module, choose M here: the
409 module will be called chsc_sch.
416 bool "Builtin IPL record support"
418 If you want to use the produced kernel to IPL directly from a
419 device, you have to merge a bootsector specific to the device
420 into the first bytes of the kernel. You will have to select the
424 prompt "IPL method generated into head.S"
428 Select "tape" if you want to IPL the image from a Tape.
430 Select "vm_reader" if you are running under VM/ESA and want
431 to IPL the image from the emulated card reader.
441 source "fs/Kconfig.binfmt"
443 config FORCE_MAX_ZONEORDER
448 bool "Pseudo page fault support"
450 Select this option, if you want to use PFAULT pseudo page fault
451 handling under VM. If running native or in LPAR, this option
452 has no effect. If your VM does not support PFAULT, PAGEEX
453 pseudo page fault handling will be used.
454 Note that VM 4.2 supports PFAULT but has a bug in its
455 implementation that causes some problems.
456 Everybody who wants to run Linux under VM != VM4.2 should select
460 bool "VM shared kernel support"
462 Select this option, if you want to share the text segment of the
463 Linux kernel between different VM guests. This reduces memory
464 usage with lots of guests but greatly increases kernel size.
465 Also if a kernel was IPL'ed from a shared segment the kexec system
467 You should only select this option if you know what you are
468 doing and want to exploit this feature.
471 tristate "Cooperative memory management"
473 Select this option, if you want to enable the kernel interface
474 to reduce the memory size of the system. This is accomplished
475 by allocating pages of memory and put them "on hold". This only
476 makes sense for a system running under VM where the unused pages
477 will be reused by VM for other guest systems. The interface
478 allows an external monitor to balance memory of many systems.
479 Everybody who wants to run Linux under VM should select this
483 bool "/proc interface to cooperative memory management"
486 Select this option to enable the /proc interface to the
487 cooperative memory management.
490 bool "IUCV special message interface to cooperative memory management"
491 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
493 Select this option to enable the special message interface to
494 the cooperative memory management.
497 bool "Linux - VM Monitor Stream, base infrastructure"
500 This provides a kernel interface for creating and updating z/VM APPLDATA
501 monitor records. The monitor records are updated at certain time
502 intervals, once the timer is started.
503 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
504 i.e. enables or disables monitoring on the Linux side.
505 A custom interval value (in seconds) can be written to
506 /proc/appldata/interval.
508 Defaults are 60 seconds interval and timer off.
509 The /proc entries can also be read from, showing the current settings.
512 tristate "Monitor memory management statistics"
513 depends on APPLDATA_BASE && VM_EVENT_COUNTERS
515 This provides memory management related data to the Linux - VM Monitor
516 Stream, like paging/swapping rate, memory utilisation, etc.
517 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
518 APPLDATA monitor record, i.e. enables or disables monitoring this record
522 The /proc entry can also be read from, showing the current settings.
524 This can also be compiled as a module, which will be called
528 tristate "Monitor OS statistics"
529 depends on APPLDATA_BASE
531 This provides OS related data to the Linux - VM Monitor Stream, like
532 CPU utilisation, etc.
533 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
534 APPLDATA monitor record, i.e. enables or disables monitoring this record
538 This can also be compiled as a module, which will be called
541 config APPLDATA_NET_SUM
542 tristate "Monitor overall network statistics"
543 depends on APPLDATA_BASE && NET
545 This provides network related data to the Linux - VM Monitor Stream,
546 currently there is only a total sum of network I/O statistics, no
548 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
549 APPLDATA monitor record, i.e. enables or disables monitoring this record
553 This can also be compiled as a module, which will be called
556 source kernel/Kconfig.hz
559 bool "s390 hypervisor file system support"
560 select SYS_HYPERVISOR
563 This is a virtual file system intended to provide accounting
564 information in an s390 hypervisor environment.
567 bool "kexec system call"
569 kexec is a system call that implements the ability to shutdown your
570 current kernel, and to start another kernel. It is like a reboot
571 but is independent of hardware/microcode support.
574 bool "zfcpdump support"
578 Select this option if you want to build an zfcpdump enabled kernel.
579 Refer to <file:Documentation/s390/zfcpdump.txt> for more details on this.
582 bool "s390 guest support for KVM (EXPERIMENTAL)"
583 depends on 64BIT && EXPERIMENTAL
586 select VIRTIO_CONSOLE
588 Select this option if you want to run the kernel as a guest under
589 the KVM hypervisor. This will add detection for KVM as well as a
590 virtio transport. If KVM is detected, the virtio console will be
594 bool "Enable seccomp to safely compute untrusted bytecode"
598 This kernel feature is useful for number crunching applications
599 that may need to compute untrusted bytecode during their
600 execution. By using pipes or other transports made available to
601 the process as file descriptors supporting the read/write
602 syscalls, it's possible to isolate those applications in
603 their own address space using seccomp. Once seccomp is
604 enabled via /proc/<pid>/seccomp, it cannot be disabled
605 and the task is only allowed to execute a few safe syscalls
606 defined by each seccomp mode.
612 menu "Power Management"
614 source "kernel/power/Kconfig"
626 source "drivers/Kconfig"
630 source "arch/s390/Kconfig.debug"
632 source "security/Kconfig"
634 source "crypto/Kconfig"
638 source "arch/s390/kvm/Kconfig"