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
99 select HAVE_PERF_EVENTS
100 select HAVE_KERNEL_GZIP
101 select HAVE_KERNEL_BZIP2
102 select HAVE_KERNEL_LZMA
103 select HAVE_KERNEL_LZO
104 select HAVE_GET_USER_PAGES_FAST
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 "Book scheduler support"
207 Book scheduler support improves the CPU scheduler's decision making
208 when dealing with machines that have several books.
211 bool "IEEE FPU emulation"
214 This option is required for IEEE compliant floating point arithmetic
215 on older S/390 machines. Say Y unless you know your machine doesn't
219 bool "Kernel support for 31 bit emulation"
221 select COMPAT_BINFMT_ELF
223 Select this option if you want to enable your system kernel to
224 handle system-calls from ELF binaries for 31 bit ESA. This option
225 (and some other stuff like libraries and such) is needed for
226 executing 31 bit applications. It is safe to say "Y".
228 config SYSVIPC_COMPAT
230 depends on COMPAT && SYSVIPC
237 config S390_EXEC_PROTECT
238 bool "Data execute protection"
240 This option allows to enable a buffer overflow protection for user
241 space programs and it also selects the addressing mode option above.
242 The kernel parameter noexec=on will enable this feature and also
243 switch the addressing modes, default is disabled. Enabling this (via
244 kernel parameter) on machines earlier than IBM System z9-109 EC/BC
245 will reduce system performance.
247 comment "Code generation options"
250 prompt "Processor type"
254 bool "S/390 model G5 and G6"
257 Select this to build a 31 bit kernel that works
258 on all S/390 and zSeries machines.
261 bool "IBM eServer zSeries model z800 and z900"
263 Select this to optimize for zSeries machines. This
264 will enable some optimizations that are not available
265 on older 31 bit only CPUs.
268 bool "IBM eServer zSeries model z890 and z990"
270 Select this enable optimizations for model z890/z990.
271 This will be slightly faster but does not work on
272 older machines such as the z900.
277 Select this to enable optimizations for IBM System z9-109, IBM
278 System z9 Enterprise Class (z9 EC), and IBM System z9 Business
279 Class (z9 BC). The kernel will be slightly faster but will not
280 work on older machines such as the z990, z890, z900, and z800.
283 bool "IBM System z10"
285 Select this to enable optimizations for IBM System z10. The
286 kernel will be slightly faster but will not work on older
287 machines such as the z990, z890, z900, z800, z9-109, z9-ec
293 bool "Pack kernel stack"
295 This option enables the compiler option -mkernel-backchain if it
296 is available. If the option is available the compiler supports
297 the new stack layout which dramatically reduces the minimum stack
298 frame size. With an old compiler a non-leaf function needs a
299 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
300 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
301 and 24 byte on 64 bit.
303 Say Y if you are unsure.
306 bool "Use 8kb for kernel stack instead of 16kb"
307 depends on PACK_STACK && 64BIT && !LOCKDEP
309 If you say Y here and the compiler supports the -mkernel-backchain
310 option the kernel will use a smaller kernel stack size. The reduced
311 size is 8kb instead of 16kb. This allows to run more threads on a
312 system and reduces the pressure on the memory management for higher
313 order page allocations.
315 Say N if you are unsure.
318 bool "Detect kernel stack overflow"
320 This option enables the compiler option -mstack-guard and
321 -mstack-size if they are available. If the compiler supports them
322 it will emit additional code to each function prolog to trigger
323 an illegal operation if the kernel stack is about to overflow.
325 Say N if you are unsure.
328 int "Size of the guard area (128-1024)"
330 depends on CHECK_STACK
333 This allows you to specify the size of the guard area at the lower
334 end of the kernel stack. If the kernel stack points into the guard
335 area on function entry an illegal operation is triggered. The size
336 needs to be a power of 2. Please keep in mind that the size of an
337 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
338 The minimum size for the stack guard should be 256 for 31 bit and
342 bool "Emit compiler warnings for function with broken stack usage"
344 This option enables the compiler options -mwarn-framesize and
345 -mwarn-dynamicstack. If the compiler supports these options it
346 will generate warnings for function which either use alloca or
347 create a stack frame bigger than CONFIG_WARN_STACK_SIZE.
349 Say N if you are unsure.
351 config WARN_STACK_SIZE
352 int "Maximum frame size considered safe (128-2048)"
354 depends on WARN_STACK
357 This allows you to specify the maximum frame size a function may
358 have without the compiler complaining about it.
360 config ARCH_POPULATES_NODE_MAP
363 comment "Kernel preemption"
365 source "kernel/Kconfig.preempt"
367 config ARCH_SPARSEMEM_ENABLE
369 select SPARSEMEM_VMEMMAP_ENABLE
370 select SPARSEMEM_VMEMMAP
371 select SPARSEMEM_STATIC if !64BIT
373 config ARCH_SPARSEMEM_DEFAULT
376 config ARCH_SELECT_MEMORY_MODEL
379 config ARCH_ENABLE_MEMORY_HOTPLUG
383 config ARCH_ENABLE_MEMORY_HOTREMOVE
386 config ARCH_HIBERNATION_POSSIBLE
391 comment "I/O subsystem configuration"
394 tristate "QDIO support"
396 This driver provides the Queued Direct I/O base support for
399 To compile this driver as a module, choose M here: the
400 module will be called qdio.
405 tristate "Support for CHSC subchannels"
407 This driver allows usage of CHSC subchannels. A CHSC subchannel
408 is usually present on LPAR only.
409 The driver creates a device /dev/chsc, which may be used to
410 obtain I/O configuration information about the machine and
411 to issue asynchronous chsc commands (DANGEROUS).
412 You will usually only want to use this interface on a special
413 LPAR designated for system management.
415 To compile this driver as a module, choose M here: the
416 module will be called chsc_sch.
423 bool "Builtin IPL record support"
425 If you want to use the produced kernel to IPL directly from a
426 device, you have to merge a bootsector specific to the device
427 into the first bytes of the kernel. You will have to select the
431 prompt "IPL method generated into head.S"
435 Select "tape" if you want to IPL the image from a Tape.
437 Select "vm_reader" if you are running under VM/ESA and want
438 to IPL the image from the emulated card reader.
448 source "fs/Kconfig.binfmt"
450 config FORCE_MAX_ZONEORDER
455 bool "Pseudo page fault support"
457 Select this option, if you want to use PFAULT pseudo page fault
458 handling under VM. If running native or in LPAR, this option
459 has no effect. If your VM does not support PFAULT, PAGEEX
460 pseudo page fault handling will be used.
461 Note that VM 4.2 supports PFAULT but has a bug in its
462 implementation that causes some problems.
463 Everybody who wants to run Linux under VM != VM4.2 should select
467 bool "VM shared kernel support"
469 Select this option, if you want to share the text segment of the
470 Linux kernel between different VM guests. This reduces memory
471 usage with lots of guests but greatly increases kernel size.
472 Also if a kernel was IPL'ed from a shared segment the kexec system
474 You should only select this option if you know what you are
475 doing and want to exploit this feature.
478 tristate "Cooperative memory management"
480 Select this option, if you want to enable the kernel interface
481 to reduce the memory size of the system. This is accomplished
482 by allocating pages of memory and put them "on hold". This only
483 makes sense for a system running under VM where the unused pages
484 will be reused by VM for other guest systems. The interface
485 allows an external monitor to balance memory of many systems.
486 Everybody who wants to run Linux under VM should select this
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"