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 ARCH_INLINE_SPIN_TRYLOCK
105 select ARCH_INLINE_SPIN_TRYLOCK_BH
106 select ARCH_INLINE_SPIN_LOCK
107 select ARCH_INLINE_SPIN_LOCK_BH
108 select ARCH_INLINE_SPIN_LOCK_IRQ
109 select ARCH_INLINE_SPIN_LOCK_IRQSAVE
110 select ARCH_INLINE_SPIN_UNLOCK
111 select ARCH_INLINE_SPIN_UNLOCK_BH
112 select ARCH_INLINE_SPIN_UNLOCK_IRQ
113 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE
114 select ARCH_INLINE_READ_TRYLOCK
115 select ARCH_INLINE_READ_LOCK
116 select ARCH_INLINE_READ_LOCK_BH
117 select ARCH_INLINE_READ_LOCK_IRQ
118 select ARCH_INLINE_READ_LOCK_IRQSAVE
119 select ARCH_INLINE_READ_UNLOCK
120 select ARCH_INLINE_READ_UNLOCK_BH
121 select ARCH_INLINE_READ_UNLOCK_IRQ
122 select ARCH_INLINE_READ_UNLOCK_IRQRESTORE
123 select ARCH_INLINE_WRITE_TRYLOCK
124 select ARCH_INLINE_WRITE_LOCK
125 select ARCH_INLINE_WRITE_LOCK_BH
126 select ARCH_INLINE_WRITE_LOCK_IRQ
127 select ARCH_INLINE_WRITE_LOCK_IRQSAVE
128 select ARCH_INLINE_WRITE_UNLOCK
129 select ARCH_INLINE_WRITE_UNLOCK_BH
130 select ARCH_INLINE_WRITE_UNLOCK_IRQ
131 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
133 config SCHED_OMIT_FRAME_POINTER
137 source "init/Kconfig"
139 source "kernel/Kconfig.freezer"
143 comment "Processor type and features"
145 source "kernel/time/Kconfig"
150 Select this option if you have a 64 bit IBM zSeries machine
151 and want to use the 64 bit addressing mode.
161 bool "Symmetric multi-processing support"
163 This enables support for systems with more than one CPU. If you have
164 a system with only one CPU, like most personal computers, say N. If
165 you have a system with more than one CPU, say Y.
167 If you say N here, the kernel will run on single and multiprocessor
168 machines, but will use only one CPU of a multiprocessor machine. If
169 you say Y here, the kernel will run on many, but not all,
170 singleprocessor machines. On a singleprocessor machine, the kernel
171 will run faster if you say N here.
173 See also the SMP-HOWTO available at
174 <http://www.tldp.org/docs.html#howto>.
176 Even if you don't know what to do here, say Y.
179 int "Maximum number of CPUs (2-64)"
182 default "32" if !64BIT
183 default "64" if 64BIT
185 This allows you to specify the maximum number of CPUs which this
186 kernel will support. The maximum supported value is 64 and the
187 minimum value which makes sense is 2.
189 This is purely to save memory - each supported CPU adds
190 approximately sixteen kilobytes to the kernel image.
193 bool "Support for hot-pluggable CPUs"
198 Say Y here to be able to turn CPUs off and on. CPUs
199 can be controlled through /sys/devices/system/cpu/cpu#.
200 Say N if you want to disable CPU hotplug.
203 bool "Book scheduler support"
206 Book scheduler support improves the CPU scheduler's decision making
207 when dealing with machines that have several books.
210 bool "IEEE FPU emulation"
213 This option is required for IEEE compliant floating point arithmetic
214 on older S/390 machines. Say Y unless you know your machine doesn't
218 bool "Kernel support for 31 bit emulation"
220 select COMPAT_BINFMT_ELF
222 Select this option if you want to enable your system kernel to
223 handle system-calls from ELF binaries for 31 bit ESA. This option
224 (and some other stuff like libraries and such) is needed for
225 executing 31 bit applications. It is safe to say "Y".
227 config SYSVIPC_COMPAT
229 depends on COMPAT && SYSVIPC
236 config S390_EXEC_PROTECT
237 bool "Data execute protection"
239 This option allows to enable a buffer overflow protection for user
240 space programs and it also selects the addressing mode option above.
241 The kernel parameter noexec=on will enable this feature and also
242 switch the addressing modes, default is disabled. Enabling this (via
243 kernel parameter) on machines earlier than IBM System z9-109 EC/BC
244 will reduce system performance.
246 comment "Code generation options"
249 prompt "Processor type"
253 bool "S/390 model G5 and G6"
256 Select this to build a 31 bit kernel that works
257 on all S/390 and zSeries machines.
260 bool "IBM eServer zSeries model z800 and z900"
262 Select this to optimize for zSeries machines. This
263 will enable some optimizations that are not available
264 on older 31 bit only CPUs.
267 bool "IBM eServer zSeries model z890 and z990"
269 Select this enable optimizations for model z890/z990.
270 This will be slightly faster but does not work on
271 older machines such as the z900.
276 Select this to enable optimizations for IBM System z9-109, IBM
277 System z9 Enterprise Class (z9 EC), and IBM System z9 Business
278 Class (z9 BC). The kernel will be slightly faster but will not
279 work on older machines such as the z990, z890, z900, and z800.
282 bool "IBM System z10"
284 Select this to enable optimizations for IBM System z10. The
285 kernel will be slightly faster but will not work on older
286 machines such as the z990, z890, z900, z800, z9-109, z9-ec
292 bool "Pack kernel stack"
294 This option enables the compiler option -mkernel-backchain if it
295 is available. If the option is available the compiler supports
296 the new stack layout which dramatically reduces the minimum stack
297 frame size. With an old compiler a non-leaf function needs a
298 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
299 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
300 and 24 byte on 64 bit.
302 Say Y if you are unsure.
305 bool "Use 8kb for kernel stack instead of 16kb"
306 depends on PACK_STACK && 64BIT && !LOCKDEP
308 If you say Y here and the compiler supports the -mkernel-backchain
309 option the kernel will use a smaller kernel stack size. The reduced
310 size is 8kb instead of 16kb. This allows to run more threads on a
311 system and reduces the pressure on the memory management for higher
312 order page allocations.
314 Say N if you are unsure.
317 bool "Detect kernel stack overflow"
319 This option enables the compiler option -mstack-guard and
320 -mstack-size if they are available. If the compiler supports them
321 it will emit additional code to each function prolog to trigger
322 an illegal operation if the kernel stack is about to overflow.
324 Say N if you are unsure.
327 int "Size of the guard area (128-1024)"
329 depends on CHECK_STACK
332 This allows you to specify the size of the guard area at the lower
333 end of the kernel stack. If the kernel stack points into the guard
334 area on function entry an illegal operation is triggered. The size
335 needs to be a power of 2. Please keep in mind that the size of an
336 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
337 The minimum size for the stack guard should be 256 for 31 bit and
341 bool "Emit compiler warnings for function with broken stack usage"
343 This option enables the compiler options -mwarn-framesize and
344 -mwarn-dynamicstack. If the compiler supports these options it
345 will generate warnings for function which either use alloca or
346 create a stack frame bigger than CONFIG_WARN_STACK_SIZE.
348 Say N if you are unsure.
350 config WARN_STACK_SIZE
351 int "Maximum frame size considered safe (128-2048)"
353 depends on WARN_STACK
356 This allows you to specify the maximum frame size a function may
357 have without the compiler complaining about it.
359 config ARCH_POPULATES_NODE_MAP
362 comment "Kernel preemption"
364 source "kernel/Kconfig.preempt"
366 config ARCH_SPARSEMEM_ENABLE
368 select SPARSEMEM_VMEMMAP_ENABLE
369 select SPARSEMEM_VMEMMAP
370 select SPARSEMEM_STATIC if !64BIT
372 config ARCH_SPARSEMEM_DEFAULT
375 config ARCH_SELECT_MEMORY_MODEL
378 config ARCH_ENABLE_MEMORY_HOTPLUG
382 config ARCH_ENABLE_MEMORY_HOTREMOVE
385 config ARCH_HIBERNATION_POSSIBLE
390 comment "I/O subsystem configuration"
393 tristate "QDIO support"
395 This driver provides the Queued Direct I/O base support for
398 To compile this driver as a module, choose M here: the
399 module will be called qdio.
404 tristate "Support for CHSC subchannels"
406 This driver allows usage of CHSC subchannels. A CHSC subchannel
407 is usually present on LPAR only.
408 The driver creates a device /dev/chsc, which may be used to
409 obtain I/O configuration information about the machine and
410 to issue asynchronous chsc commands (DANGEROUS).
411 You will usually only want to use this interface on a special
412 LPAR designated for system management.
414 To compile this driver as a module, choose M here: the
415 module will be called chsc_sch.
422 bool "Builtin IPL record support"
424 If you want to use the produced kernel to IPL directly from a
425 device, you have to merge a bootsector specific to the device
426 into the first bytes of the kernel. You will have to select the
430 prompt "IPL method generated into head.S"
434 Select "tape" if you want to IPL the image from a Tape.
436 Select "vm_reader" if you are running under VM/ESA and want
437 to IPL the image from the emulated card reader.
447 source "fs/Kconfig.binfmt"
449 config FORCE_MAX_ZONEORDER
454 bool "Pseudo page fault support"
456 Select this option, if you want to use PFAULT pseudo page fault
457 handling under VM. If running native or in LPAR, this option
458 has no effect. If your VM does not support PFAULT, PAGEEX
459 pseudo page fault handling will be used.
460 Note that VM 4.2 supports PFAULT but has a bug in its
461 implementation that causes some problems.
462 Everybody who wants to run Linux under VM != VM4.2 should select
466 bool "VM shared kernel support"
468 Select this option, if you want to share the text segment of the
469 Linux kernel between different VM guests. This reduces memory
470 usage with lots of guests but greatly increases kernel size.
471 Also if a kernel was IPL'ed from a shared segment the kexec system
473 You should only select this option if you know what you are
474 doing and want to exploit this feature.
477 tristate "Cooperative memory management"
479 Select this option, if you want to enable the kernel interface
480 to reduce the memory size of the system. This is accomplished
481 by allocating pages of memory and put them "on hold". This only
482 makes sense for a system running under VM where the unused pages
483 will be reused by VM for other guest systems. The interface
484 allows an external monitor to balance memory of many systems.
485 Everybody who wants to run Linux under VM should select this
489 bool "IUCV special message interface to cooperative memory management"
490 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
492 Select this option to enable the special message interface to
493 the cooperative memory management.
496 bool "Linux - VM Monitor Stream, base infrastructure"
499 This provides a kernel interface for creating and updating z/VM APPLDATA
500 monitor records. The monitor records are updated at certain time
501 intervals, once the timer is started.
502 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
503 i.e. enables or disables monitoring on the Linux side.
504 A custom interval value (in seconds) can be written to
505 /proc/appldata/interval.
507 Defaults are 60 seconds interval and timer off.
508 The /proc entries can also be read from, showing the current settings.
511 tristate "Monitor memory management statistics"
512 depends on APPLDATA_BASE && VM_EVENT_COUNTERS
514 This provides memory management related data to the Linux - VM Monitor
515 Stream, like paging/swapping rate, memory utilisation, etc.
516 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
517 APPLDATA monitor record, i.e. enables or disables monitoring this record
521 The /proc entry can also be read from, showing the current settings.
523 This can also be compiled as a module, which will be called
527 tristate "Monitor OS statistics"
528 depends on APPLDATA_BASE
530 This provides OS related data to the Linux - VM Monitor Stream, like
531 CPU utilisation, etc.
532 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
533 APPLDATA monitor record, i.e. enables or disables monitoring this record
537 This can also be compiled as a module, which will be called
540 config APPLDATA_NET_SUM
541 tristate "Monitor overall network statistics"
542 depends on APPLDATA_BASE && NET
544 This provides network related data to the Linux - VM Monitor Stream,
545 currently there is only a total sum of network I/O statistics, no
547 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
548 APPLDATA monitor record, i.e. enables or disables monitoring this record
552 This can also be compiled as a module, which will be called
555 source kernel/Kconfig.hz
558 bool "s390 hypervisor file system support"
559 select SYS_HYPERVISOR
562 This is a virtual file system intended to provide accounting
563 information in an s390 hypervisor environment.
566 bool "kexec system call"
568 kexec is a system call that implements the ability to shutdown your
569 current kernel, and to start another kernel. It is like a reboot
570 but is independent of hardware/microcode support.
573 bool "zfcpdump support"
577 Select this option if you want to build an zfcpdump enabled kernel.
578 Refer to <file:Documentation/s390/zfcpdump.txt> for more details on this.
581 bool "s390 guest support for KVM (EXPERIMENTAL)"
582 depends on 64BIT && EXPERIMENTAL
585 select VIRTIO_CONSOLE
587 Select this option if you want to run the kernel as a guest under
588 the KVM hypervisor. This will add detection for KVM as well as a
589 virtio transport. If KVM is detected, the virtio console will be
593 bool "Enable seccomp to safely compute untrusted bytecode"
597 This kernel feature is useful for number crunching applications
598 that may need to compute untrusted bytecode during their
599 execution. By using pipes or other transports made available to
600 the process as file descriptors supporting the read/write
601 syscalls, it's possible to isolate those applications in
602 their own address space using seccomp. Once seccomp is
603 enabled via /proc/<pid>/seccomp, it cannot be disabled
604 and the task is only allowed to execute a few safe syscalls
605 defined by each seccomp mode.
611 menu "Power Management"
613 source "kernel/power/Kconfig"
625 source "drivers/Kconfig"
629 source "arch/s390/Kconfig.debug"
631 source "security/Kconfig"
633 source "crypto/Kconfig"
637 source "arch/s390/kvm/Kconfig"