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
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_FTRACE_SYSCALLS
88 select HAVE_DYNAMIC_FTRACE
89 select HAVE_FUNCTION_GRAPH_TRACER
90 select HAVE_DEFAULT_NO_SPIN_MUTEXES
93 select HAVE_KRETPROBES
94 select HAVE_KVM if 64BIT
95 select HAVE_ARCH_TRACEHOOK
96 select INIT_ALL_POSSIBLE
97 select HAVE_PERF_COUNTERS
98 select GENERIC_ATOMIC64 if !64BIT
100 config SCHED_OMIT_FRAME_POINTER
104 source "init/Kconfig"
106 source "kernel/Kconfig.freezer"
110 comment "Processor type and features"
112 source "kernel/time/Kconfig"
117 Select this option if you have a 64 bit IBM zSeries machine
118 and want to use the 64 bit addressing mode.
125 bool "Symmetric multi-processing support"
127 This enables support for systems with more than one CPU. If you have
128 a system with only one CPU, like most personal computers, say N. If
129 you have a system with more than one CPU, say Y.
131 If you say N here, the kernel will run on single and multiprocessor
132 machines, but will use only one CPU of a multiprocessor machine. If
133 you say Y here, the kernel will run on many, but not all,
134 singleprocessor machines. On a singleprocessor machine, the kernel
135 will run faster if you say N here.
137 See also the SMP-HOWTO available at
138 <http://www.tldp.org/docs.html#howto>.
140 Even if you don't know what to do here, say Y.
143 int "Maximum number of CPUs (2-64)"
146 default "32" if !64BIT
147 default "64" if 64BIT
149 This allows you to specify the maximum number of CPUs which this
150 kernel will support. The maximum supported value is 64 and the
151 minimum value which makes sense is 2.
153 This is purely to save memory - each supported CPU adds
154 approximately sixteen kilobytes to the kernel image.
157 bool "Support for hot-pluggable CPUs"
162 Say Y here to be able to turn CPUs off and on. CPUs
163 can be controlled through /sys/devices/system/cpu/cpu#.
164 Say N if you want to disable CPU hotplug.
167 bool "IEEE FPU emulation"
170 This option is required for IEEE compliant floating point arithmetic
171 on older S/390 machines. Say Y unless you know your machine doesn't
175 bool "Kernel support for 31 bit emulation"
177 select COMPAT_BINFMT_ELF
179 Select this option if you want to enable your system kernel to
180 handle system-calls from ELF binaries for 31 bit ESA. This option
181 (and some other stuff like libraries and such) is needed for
182 executing 31 bit applications. It is safe to say "Y".
184 config SYSVIPC_COMPAT
186 depends on COMPAT && SYSVIPC
193 config S390_SWITCH_AMODE
194 bool "Switch kernel/user addressing modes"
196 This option allows to switch the addressing modes of kernel and user
197 space. The kernel parameter switch_amode=on will enable this feature,
198 default is disabled. Enabling this (via kernel parameter) on machines
199 earlier than IBM System z9-109 EC/BC will reduce system performance.
201 Note that this option will also be selected by selecting the execute
202 protection option below. Enabling the execute protection via the
203 noexec kernel parameter will also switch the addressing modes,
204 independent of the switch_amode kernel parameter.
207 config S390_EXEC_PROTECT
208 bool "Data execute protection"
209 select S390_SWITCH_AMODE
211 This option allows to enable a buffer overflow protection for user
212 space programs and it also selects the addressing mode option above.
213 The kernel parameter noexec=on will enable this feature and also
214 switch the addressing modes, default is disabled. Enabling this (via
215 kernel parameter) on machines earlier than IBM System z9-109 EC/BC
216 will reduce system performance.
218 comment "Code generation options"
221 prompt "Processor type"
225 bool "S/390 model G5 and G6"
228 Select this to build a 31 bit kernel that works
229 on all S/390 and zSeries machines.
232 bool "IBM eServer zSeries model z800 and z900"
234 Select this to optimize for zSeries machines. This
235 will enable some optimizations that are not available
236 on older 31 bit only CPUs.
239 bool "IBM eServer zSeries model z890 and z990"
241 Select this enable optimizations for model z890/z990.
242 This will be slightly faster but does not work on
243 older machines such as the z900.
248 Select this to enable optimizations for IBM System z9-109, IBM
249 System z9 Enterprise Class (z9 EC), and IBM System z9 Business
250 Class (z9 BC). The kernel will be slightly faster but will not
251 work on older machines such as the z990, z890, z900, and z800.
254 bool "IBM System z10"
256 Select this to enable optimizations for IBM System z10. The
257 kernel will be slightly faster but will not work on older
258 machines such as the z990, z890, z900, z800, z9-109, z9-ec
264 bool "Pack kernel stack"
266 This option enables the compiler option -mkernel-backchain if it
267 is available. If the option is available the compiler supports
268 the new stack layout which dramatically reduces the minimum stack
269 frame size. With an old compiler a non-leaf function needs a
270 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
271 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
272 and 24 byte on 64 bit.
274 Say Y if you are unsure.
277 bool "Use 8kb for kernel stack instead of 16kb"
278 depends on PACK_STACK && 64BIT && !LOCKDEP
280 If you say Y here and the compiler supports the -mkernel-backchain
281 option the kernel will use a smaller kernel stack size. The reduced
282 size is 8kb instead of 16kb. This allows to run more threads on a
283 system and reduces the pressure on the memory management for higher
284 order page allocations.
286 Say N if you are unsure.
289 bool "Detect kernel stack overflow"
291 This option enables the compiler option -mstack-guard and
292 -mstack-size if they are available. If the compiler supports them
293 it will emit additional code to each function prolog to trigger
294 an illegal operation if the kernel stack is about to overflow.
296 Say N if you are unsure.
299 int "Size of the guard area (128-1024)"
301 depends on CHECK_STACK
304 This allows you to specify the size of the guard area at the lower
305 end of the kernel stack. If the kernel stack points into the guard
306 area on function entry an illegal operation is triggered. The size
307 needs to be a power of 2. Please keep in mind that the size of an
308 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
309 The minimum size for the stack guard should be 256 for 31 bit and
313 bool "Emit compiler warnings for function with broken stack usage"
315 This option enables the compiler options -mwarn-framesize and
316 -mwarn-dynamicstack. If the compiler supports these options it
317 will generate warnings for function which either use alloca or
318 create a stack frame bigger than CONFIG_WARN_STACK_SIZE.
320 Say N if you are unsure.
322 config WARN_STACK_SIZE
323 int "Maximum frame size considered safe (128-2048)"
325 depends on WARN_STACK
328 This allows you to specify the maximum frame size a function may
329 have without the compiler complaining about it.
331 config ARCH_POPULATES_NODE_MAP
334 comment "Kernel preemption"
336 source "kernel/Kconfig.preempt"
338 config ARCH_SPARSEMEM_ENABLE
340 select SPARSEMEM_VMEMMAP_ENABLE
341 select SPARSEMEM_VMEMMAP
342 select SPARSEMEM_STATIC if !64BIT
344 config ARCH_SPARSEMEM_DEFAULT
347 config ARCH_SELECT_MEMORY_MODEL
350 config ARCH_ENABLE_MEMORY_HOTPLUG
354 config ARCH_ENABLE_MEMORY_HOTREMOVE
357 config ARCH_HIBERNATION_POSSIBLE
362 comment "I/O subsystem configuration"
365 tristate "QDIO support"
367 This driver provides the Queued Direct I/O base support for
370 To compile this driver as a module, choose M here: the
371 module will be called qdio.
376 tristate "Support for CHSC subchannels"
378 This driver allows usage of CHSC subchannels. A CHSC subchannel
379 is usually present on LPAR only.
380 The driver creates a device /dev/chsc, which may be used to
381 obtain I/O configuration information about the machine and
382 to issue asynchronous chsc commands (DANGEROUS).
383 You will usually only want to use this interface on a special
384 LPAR designated for system management.
386 To compile this driver as a module, choose M here: the
387 module will be called chsc_sch.
394 bool "Builtin IPL record support"
396 If you want to use the produced kernel to IPL directly from a
397 device, you have to merge a bootsector specific to the device
398 into the first bytes of the kernel. You will have to select the
402 prompt "IPL method generated into head.S"
406 Select "tape" if you want to IPL the image from a Tape.
408 Select "vm_reader" if you are running under VM/ESA and want
409 to IPL the image from the emulated card reader.
419 source "fs/Kconfig.binfmt"
421 config FORCE_MAX_ZONEORDER
426 bool "Show crashed user process info"
428 Say Y to print all process fault locations to the console. This is
429 a debugging option; you probably do not want to set it unless you
430 are an S390 port maintainer.
433 bool "Pseudo page fault support"
435 Select this option, if you want to use PFAULT pseudo page fault
436 handling under VM. If running native or in LPAR, this option
437 has no effect. If your VM does not support PFAULT, PAGEEX
438 pseudo page fault handling will be used.
439 Note that VM 4.2 supports PFAULT but has a bug in its
440 implementation that causes some problems.
441 Everybody who wants to run Linux under VM != VM4.2 should select
445 bool "VM shared kernel support"
447 Select this option, if you want to share the text segment of the
448 Linux kernel between different VM guests. This reduces memory
449 usage with lots of guests but greatly increases kernel size.
450 Also if a kernel was IPL'ed from a shared segment the kexec system
452 You should only select this option if you know what you are
453 doing and want to exploit this feature.
456 tristate "Cooperative memory management"
458 Select this option, if you want to enable the kernel interface
459 to reduce the memory size of the system. This is accomplished
460 by allocating pages of memory and put them "on hold". This only
461 makes sense for a system running under VM where the unused pages
462 will be reused by VM for other guest systems. The interface
463 allows an external monitor to balance memory of many systems.
464 Everybody who wants to run Linux under VM should select this
468 bool "/proc interface to cooperative memory management"
471 Select this option to enable the /proc interface to the
472 cooperative memory management.
475 bool "IUCV special message interface to cooperative memory management"
476 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
478 Select this option to enable the special message interface to
479 the cooperative memory management.
482 bool "Unused page notification"
484 This enables the notification of unused pages to the
485 hypervisor. The ESSA instruction is used to do the states
486 changes between a page that has content and the unused state.
489 bool "Linux - VM Monitor Stream, base infrastructure"
492 This provides a kernel interface for creating and updating z/VM APPLDATA
493 monitor records. The monitor records are updated at certain time
494 intervals, once the timer is started.
495 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
496 i.e. enables or disables monitoring on the Linux side.
497 A custom interval value (in seconds) can be written to
498 /proc/appldata/interval.
500 Defaults are 60 seconds interval and timer off.
501 The /proc entries can also be read from, showing the current settings.
504 tristate "Monitor memory management statistics"
505 depends on APPLDATA_BASE && VM_EVENT_COUNTERS
507 This provides memory management related data to the Linux - VM Monitor
508 Stream, like paging/swapping rate, memory utilisation, etc.
509 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
510 APPLDATA monitor record, i.e. enables or disables monitoring this record
514 The /proc entry can also be read from, showing the current settings.
516 This can also be compiled as a module, which will be called
520 tristate "Monitor OS statistics"
521 depends on APPLDATA_BASE
523 This provides OS related data to the Linux - VM Monitor Stream, like
524 CPU utilisation, etc.
525 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
526 APPLDATA monitor record, i.e. enables or disables monitoring this record
530 This can also be compiled as a module, which will be called
533 config APPLDATA_NET_SUM
534 tristate "Monitor overall network statistics"
535 depends on APPLDATA_BASE && NET
537 This provides network related data to the Linux - VM Monitor Stream,
538 currently there is only a total sum of network I/O statistics, no
540 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
541 APPLDATA monitor record, i.e. enables or disables monitoring this record
545 This can also be compiled as a module, which will be called
548 source kernel/Kconfig.hz
551 bool "s390 hypervisor file system support"
552 select SYS_HYPERVISOR
555 This is a virtual file system intended to provide accounting
556 information in an s390 hypervisor environment.
559 bool "kexec system call"
561 kexec is a system call that implements the ability to shutdown your
562 current kernel, and to start another kernel. It is like a reboot
563 but is independent of hardware/microcode support.
566 bool "zfcpdump support"
570 Select this option if you want to build an zfcpdump enabled kernel.
571 Refer to <file:Documentation/s390/zfcpdump.txt> for more details on this.
574 bool "s390 guest support for KVM (EXPERIMENTAL)"
575 depends on 64BIT && EXPERIMENTAL
578 select VIRTIO_CONSOLE
580 Select this option if you want to run the kernel as a guest under
581 the KVM hypervisor. This will add detection for KVM as well as a
582 virtio transport. If KVM is detected, the virtio console will be
586 bool "Enable seccomp to safely compute untrusted bytecode"
590 This kernel feature is useful for number crunching applications
591 that may need to compute untrusted bytecode during their
592 execution. By using pipes or other transports made available to
593 the process as file descriptors supporting the read/write
594 syscalls, it's possible to isolate those applications in
595 their own address space using seccomp. Once seccomp is
596 enabled via /proc/<pid>/seccomp, it cannot be disabled
597 and the task is only allowed to execute a few safe syscalls
598 defined by each seccomp mode.
604 menu "Power Management"
606 source "kernel/power/Kconfig"
618 source "drivers/Kconfig"
622 source "arch/s390/Kconfig.debug"
624 source "security/Kconfig"
626 source "crypto/Kconfig"
630 source "arch/s390/kvm/Kconfig"