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 "IEEE FPU emulation"
205 This option is required for IEEE compliant floating point arithmetic
206 on older S/390 machines. Say Y unless you know your machine doesn't
210 bool "Kernel support for 31 bit emulation"
212 select COMPAT_BINFMT_ELF
214 Select this option if you want to enable your system kernel to
215 handle system-calls from ELF binaries for 31 bit ESA. This option
216 (and some other stuff like libraries and such) is needed for
217 executing 31 bit applications. It is safe to say "Y".
219 config SYSVIPC_COMPAT
221 depends on COMPAT && SYSVIPC
228 config S390_EXEC_PROTECT
229 bool "Data execute protection"
231 This option allows to enable a buffer overflow protection for user
232 space programs and it also selects the addressing mode option above.
233 The kernel parameter noexec=on will enable this feature and also
234 switch the addressing modes, default is disabled. Enabling this (via
235 kernel parameter) on machines earlier than IBM System z9-109 EC/BC
236 will reduce system performance.
238 comment "Code generation options"
241 prompt "Processor type"
245 bool "S/390 model G5 and G6"
248 Select this to build a 31 bit kernel that works
249 on all S/390 and zSeries machines.
252 bool "IBM eServer zSeries model z800 and z900"
254 Select this to optimize for zSeries machines. This
255 will enable some optimizations that are not available
256 on older 31 bit only CPUs.
259 bool "IBM eServer zSeries model z890 and z990"
261 Select this enable optimizations for model z890/z990.
262 This will be slightly faster but does not work on
263 older machines such as the z900.
268 Select this to enable optimizations for IBM System z9-109, IBM
269 System z9 Enterprise Class (z9 EC), and IBM System z9 Business
270 Class (z9 BC). The kernel will be slightly faster but will not
271 work on older machines such as the z990, z890, z900, and z800.
274 bool "IBM System z10"
276 Select this to enable optimizations for IBM System z10. The
277 kernel will be slightly faster but will not work on older
278 machines such as the z990, z890, z900, z800, z9-109, z9-ec
284 bool "Pack kernel stack"
286 This option enables the compiler option -mkernel-backchain if it
287 is available. If the option is available the compiler supports
288 the new stack layout which dramatically reduces the minimum stack
289 frame size. With an old compiler a non-leaf function needs a
290 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
291 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
292 and 24 byte on 64 bit.
294 Say Y if you are unsure.
297 bool "Use 8kb for kernel stack instead of 16kb"
298 depends on PACK_STACK && 64BIT && !LOCKDEP
300 If you say Y here and the compiler supports the -mkernel-backchain
301 option the kernel will use a smaller kernel stack size. The reduced
302 size is 8kb instead of 16kb. This allows to run more threads on a
303 system and reduces the pressure on the memory management for higher
304 order page allocations.
306 Say N if you are unsure.
309 bool "Detect kernel stack overflow"
311 This option enables the compiler option -mstack-guard and
312 -mstack-size if they are available. If the compiler supports them
313 it will emit additional code to each function prolog to trigger
314 an illegal operation if the kernel stack is about to overflow.
316 Say N if you are unsure.
319 int "Size of the guard area (128-1024)"
321 depends on CHECK_STACK
324 This allows you to specify the size of the guard area at the lower
325 end of the kernel stack. If the kernel stack points into the guard
326 area on function entry an illegal operation is triggered. The size
327 needs to be a power of 2. Please keep in mind that the size of an
328 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
329 The minimum size for the stack guard should be 256 for 31 bit and
333 bool "Emit compiler warnings for function with broken stack usage"
335 This option enables the compiler options -mwarn-framesize and
336 -mwarn-dynamicstack. If the compiler supports these options it
337 will generate warnings for function which either use alloca or
338 create a stack frame bigger than CONFIG_WARN_STACK_SIZE.
340 Say N if you are unsure.
342 config WARN_STACK_SIZE
343 int "Maximum frame size considered safe (128-2048)"
345 depends on WARN_STACK
348 This allows you to specify the maximum frame size a function may
349 have without the compiler complaining about it.
351 config ARCH_POPULATES_NODE_MAP
354 comment "Kernel preemption"
356 source "kernel/Kconfig.preempt"
358 config ARCH_SPARSEMEM_ENABLE
360 select SPARSEMEM_VMEMMAP_ENABLE
361 select SPARSEMEM_VMEMMAP
362 select SPARSEMEM_STATIC if !64BIT
364 config ARCH_SPARSEMEM_DEFAULT
367 config ARCH_SELECT_MEMORY_MODEL
370 config ARCH_ENABLE_MEMORY_HOTPLUG
374 config ARCH_ENABLE_MEMORY_HOTREMOVE
377 config ARCH_HIBERNATION_POSSIBLE
382 comment "I/O subsystem configuration"
385 tristate "QDIO support"
387 This driver provides the Queued Direct I/O base support for
390 To compile this driver as a module, choose M here: the
391 module will be called qdio.
396 tristate "Support for CHSC subchannels"
398 This driver allows usage of CHSC subchannels. A CHSC subchannel
399 is usually present on LPAR only.
400 The driver creates a device /dev/chsc, which may be used to
401 obtain I/O configuration information about the machine and
402 to issue asynchronous chsc commands (DANGEROUS).
403 You will usually only want to use this interface on a special
404 LPAR designated for system management.
406 To compile this driver as a module, choose M here: the
407 module will be called chsc_sch.
414 bool "Builtin IPL record support"
416 If you want to use the produced kernel to IPL directly from a
417 device, you have to merge a bootsector specific to the device
418 into the first bytes of the kernel. You will have to select the
422 prompt "IPL method generated into head.S"
426 Select "tape" if you want to IPL the image from a Tape.
428 Select "vm_reader" if you are running under VM/ESA and want
429 to IPL the image from the emulated card reader.
439 source "fs/Kconfig.binfmt"
441 config FORCE_MAX_ZONEORDER
446 bool "Pseudo page fault support"
448 Select this option, if you want to use PFAULT pseudo page fault
449 handling under VM. If running native or in LPAR, this option
450 has no effect. If your VM does not support PFAULT, PAGEEX
451 pseudo page fault handling will be used.
452 Note that VM 4.2 supports PFAULT but has a bug in its
453 implementation that causes some problems.
454 Everybody who wants to run Linux under VM != VM4.2 should select
458 bool "VM shared kernel support"
460 Select this option, if you want to share the text segment of the
461 Linux kernel between different VM guests. This reduces memory
462 usage with lots of guests but greatly increases kernel size.
463 Also if a kernel was IPL'ed from a shared segment the kexec system
465 You should only select this option if you know what you are
466 doing and want to exploit this feature.
469 tristate "Cooperative memory management"
471 Select this option, if you want to enable the kernel interface
472 to reduce the memory size of the system. This is accomplished
473 by allocating pages of memory and put them "on hold". This only
474 makes sense for a system running under VM where the unused pages
475 will be reused by VM for other guest systems. The interface
476 allows an external monitor to balance memory of many systems.
477 Everybody who wants to run Linux under VM should select this
481 bool "IUCV special message interface to cooperative memory management"
482 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
484 Select this option to enable the special message interface to
485 the cooperative memory management.
488 bool "Linux - VM Monitor Stream, base infrastructure"
491 This provides a kernel interface for creating and updating z/VM APPLDATA
492 monitor records. The monitor records are updated at certain time
493 intervals, once the timer is started.
494 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
495 i.e. enables or disables monitoring on the Linux side.
496 A custom interval value (in seconds) can be written to
497 /proc/appldata/interval.
499 Defaults are 60 seconds interval and timer off.
500 The /proc entries can also be read from, showing the current settings.
503 tristate "Monitor memory management statistics"
504 depends on APPLDATA_BASE && VM_EVENT_COUNTERS
506 This provides memory management related data to the Linux - VM Monitor
507 Stream, like paging/swapping rate, memory utilisation, etc.
508 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
509 APPLDATA monitor record, i.e. enables or disables monitoring this record
513 The /proc entry can also be read from, showing the current settings.
515 This can also be compiled as a module, which will be called
519 tristate "Monitor OS statistics"
520 depends on APPLDATA_BASE
522 This provides OS related data to the Linux - VM Monitor Stream, like
523 CPU utilisation, etc.
524 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
525 APPLDATA monitor record, i.e. enables or disables monitoring this record
529 This can also be compiled as a module, which will be called
532 config APPLDATA_NET_SUM
533 tristate "Monitor overall network statistics"
534 depends on APPLDATA_BASE && NET
536 This provides network related data to the Linux - VM Monitor Stream,
537 currently there is only a total sum of network I/O statistics, no
539 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
540 APPLDATA monitor record, i.e. enables or disables monitoring this record
544 This can also be compiled as a module, which will be called
547 source kernel/Kconfig.hz
550 bool "s390 hypervisor file system support"
551 select SYS_HYPERVISOR
554 This is a virtual file system intended to provide accounting
555 information in an s390 hypervisor environment.
558 bool "kexec system call"
560 kexec is a system call that implements the ability to shutdown your
561 current kernel, and to start another kernel. It is like a reboot
562 but is independent of hardware/microcode support.
565 bool "zfcpdump support"
569 Select this option if you want to build an zfcpdump enabled kernel.
570 Refer to <file:Documentation/s390/zfcpdump.txt> for more details on this.
573 bool "s390 guest support for KVM (EXPERIMENTAL)"
574 depends on 64BIT && EXPERIMENTAL
577 select VIRTIO_CONSOLE
579 Select this option if you want to run the kernel as a guest under
580 the KVM hypervisor. This will add detection for KVM as well as a
581 virtio transport. If KVM is detected, the virtio console will be
585 bool "Enable seccomp to safely compute untrusted bytecode"
589 This kernel feature is useful for number crunching applications
590 that may need to compute untrusted bytecode during their
591 execution. By using pipes or other transports made available to
592 the process as file descriptors supporting the read/write
593 syscalls, it's possible to isolate those applications in
594 their own address space using seccomp. Once seccomp is
595 enabled via /proc/<pid>/seccomp, it cannot be disabled
596 and the task is only allowed to execute a few safe syscalls
597 defined by each seccomp mode.
603 menu "Power Management"
605 source "kernel/power/Kconfig"
617 source "drivers/Kconfig"
621 source "arch/s390/Kconfig.debug"
623 source "security/Kconfig"
625 source "crypto/Kconfig"
629 source "arch/s390/kvm/Kconfig"