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 config HAVE_LEGACY_PER_CPU_AREA
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_FTRACE_SYSCALLS
91 select HAVE_DYNAMIC_FTRACE
92 select HAVE_FUNCTION_GRAPH_TRACER
93 select HAVE_DEFAULT_NO_SPIN_MUTEXES
96 select HAVE_KRETPROBES
97 select HAVE_KVM if 64BIT
98 select HAVE_ARCH_TRACEHOOK
99 select INIT_ALL_POSSIBLE
101 source "init/Kconfig"
103 source "kernel/Kconfig.freezer"
107 comment "Processor type and features"
109 source "kernel/time/Kconfig"
114 Select this option if you have a 64 bit IBM zSeries machine
115 and want to use the 64 bit addressing mode.
122 bool "Symmetric multi-processing support"
124 This enables support for systems with more than one CPU. If you have
125 a system with only one CPU, like most personal computers, say N. If
126 you have a system with more than one CPU, say Y.
128 If you say N here, the kernel will run on single and multiprocessor
129 machines, but will use only one CPU of a multiprocessor machine. If
130 you say Y here, the kernel will run on many, but not all,
131 singleprocessor machines. On a singleprocessor machine, the kernel
132 will run faster if you say N here.
134 See also the SMP-HOWTO available at
135 <http://www.tldp.org/docs.html#howto>.
137 Even if you don't know what to do here, say Y.
140 int "Maximum number of CPUs (2-64)"
143 default "32" if !64BIT
144 default "64" if 64BIT
146 This allows you to specify the maximum number of CPUs which this
147 kernel will support. The maximum supported value is 64 and the
148 minimum value which makes sense is 2.
150 This is purely to save memory - each supported CPU adds
151 approximately sixteen kilobytes to the kernel image.
154 bool "Support for hot-pluggable CPUs"
159 Say Y here to be able to turn CPUs off and on. CPUs
160 can be controlled through /sys/devices/system/cpu/cpu#.
161 Say N if you want to disable CPU hotplug.
164 bool "IEEE FPU emulation"
167 This option is required for IEEE compliant floating point arithmetic
168 on older S/390 machines. Say Y unless you know your machine doesn't
172 bool "Kernel support for 31 bit emulation"
174 select COMPAT_BINFMT_ELF
176 Select this option if you want to enable your system kernel to
177 handle system-calls from ELF binaries for 31 bit ESA. This option
178 (and some other stuff like libraries and such) is needed for
179 executing 31 bit applications. It is safe to say "Y".
181 config SYSVIPC_COMPAT
183 depends on COMPAT && SYSVIPC
190 config S390_SWITCH_AMODE
191 bool "Switch kernel/user addressing modes"
193 This option allows to switch the addressing modes of kernel and user
194 space. The kernel parameter switch_amode=on will enable this feature,
195 default is disabled. Enabling this (via kernel parameter) on machines
196 earlier than IBM System z9-109 EC/BC will reduce system performance.
198 Note that this option will also be selected by selecting the execute
199 protection option below. Enabling the execute protection via the
200 noexec kernel parameter will also switch the addressing modes,
201 independent of the switch_amode kernel parameter.
204 config S390_EXEC_PROTECT
205 bool "Data execute protection"
206 select S390_SWITCH_AMODE
208 This option allows to enable a buffer overflow protection for user
209 space programs and it also selects the addressing mode option above.
210 The kernel parameter noexec=on will enable this feature and also
211 switch the addressing modes, default is disabled. Enabling this (via
212 kernel parameter) on machines earlier than IBM System z9-109 EC/BC
213 will reduce system performance.
215 comment "Code generation options"
218 prompt "Processor type"
222 bool "S/390 model G5 and G6"
225 Select this to build a 31 bit kernel that works
226 on all S/390 and zSeries machines.
229 bool "IBM eServer zSeries model z800 and z900"
231 Select this to optimize for zSeries machines. This
232 will enable some optimizations that are not available
233 on older 31 bit only CPUs.
236 bool "IBM eServer zSeries model z890 and z990"
238 Select this enable optimizations for model z890/z990.
239 This will be slightly faster but does not work on
240 older machines such as the z900.
245 Select this to enable optimizations for IBM System z9-109, IBM
246 System z9 Enterprise Class (z9 EC), and IBM System z9 Business
247 Class (z9 BC). The kernel will be slightly faster but will not
248 work on older machines such as the z990, z890, z900, and z800.
251 bool "IBM System z10"
253 Select this to enable optimizations for IBM System z10. The
254 kernel will be slightly faster but will not work on older
255 machines such as the z990, z890, z900, z800, z9-109, z9-ec
261 bool "Pack kernel stack"
263 This option enables the compiler option -mkernel-backchain if it
264 is available. If the option is available the compiler supports
265 the new stack layout which dramatically reduces the minimum stack
266 frame size. With an old compiler a non-leaf function needs a
267 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
268 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
269 and 24 byte on 64 bit.
271 Say Y if you are unsure.
274 bool "Use 8kb for kernel stack instead of 16kb"
275 depends on PACK_STACK && 64BIT && !LOCKDEP
277 If you say Y here and the compiler supports the -mkernel-backchain
278 option the kernel will use a smaller kernel stack size. The reduced
279 size is 8kb instead of 16kb. This allows to run more threads on a
280 system and reduces the pressure on the memory management for higher
281 order page allocations.
283 Say N if you are unsure.
286 bool "Detect kernel stack overflow"
288 This option enables the compiler option -mstack-guard and
289 -mstack-size if they are available. If the compiler supports them
290 it will emit additional code to each function prolog to trigger
291 an illegal operation if the kernel stack is about to overflow.
293 Say N if you are unsure.
296 int "Size of the guard area (128-1024)"
298 depends on CHECK_STACK
301 This allows you to specify the size of the guard area at the lower
302 end of the kernel stack. If the kernel stack points into the guard
303 area on function entry an illegal operation is triggered. The size
304 needs to be a power of 2. Please keep in mind that the size of an
305 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
306 The minimum size for the stack guard should be 256 for 31 bit and
310 bool "Emit compiler warnings for function with broken stack usage"
312 This option enables the compiler options -mwarn-framesize and
313 -mwarn-dynamicstack. If the compiler supports these options it
314 will generate warnings for function which either use alloca or
315 create a stack frame bigger than CONFIG_WARN_STACK_SIZE.
317 Say N if you are unsure.
319 config WARN_STACK_SIZE
320 int "Maximum frame size considered safe (128-2048)"
322 depends on WARN_STACK
325 This allows you to specify the maximum frame size a function may
326 have without the compiler complaining about it.
328 config ARCH_POPULATES_NODE_MAP
331 comment "Kernel preemption"
333 source "kernel/Kconfig.preempt"
335 config ARCH_SPARSEMEM_ENABLE
337 select SPARSEMEM_VMEMMAP_ENABLE
338 select SPARSEMEM_VMEMMAP
339 select SPARSEMEM_STATIC if !64BIT
341 config ARCH_SPARSEMEM_DEFAULT
344 config ARCH_SELECT_MEMORY_MODEL
347 config ARCH_ENABLE_MEMORY_HOTPLUG
351 config ARCH_ENABLE_MEMORY_HOTREMOVE
354 config ARCH_HIBERNATION_POSSIBLE
359 comment "I/O subsystem configuration"
362 tristate "QDIO support"
364 This driver provides the Queued Direct I/O base support for
367 To compile this driver as a module, choose M here: the
368 module will be called qdio.
373 tristate "Support for CHSC subchannels"
375 This driver allows usage of CHSC subchannels. A CHSC subchannel
376 is usually present on LPAR only.
377 The driver creates a device /dev/chsc, which may be used to
378 obtain I/O configuration information about the machine and
379 to issue asynchronous chsc commands (DANGEROUS).
380 You will usually only want to use this interface on a special
381 LPAR designated for system management.
383 To compile this driver as a module, choose M here: the
384 module will be called chsc_sch.
391 bool "Builtin IPL record support"
393 If you want to use the produced kernel to IPL directly from a
394 device, you have to merge a bootsector specific to the device
395 into the first bytes of the kernel. You will have to select the
399 prompt "IPL method generated into head.S"
403 Select "tape" if you want to IPL the image from a Tape.
405 Select "vm_reader" if you are running under VM/ESA and want
406 to IPL the image from the emulated card reader.
416 source "fs/Kconfig.binfmt"
418 config FORCE_MAX_ZONEORDER
423 bool "Show crashed user process info"
425 Say Y to print all process fault locations to the console. This is
426 a debugging option; you probably do not want to set it unless you
427 are an S390 port maintainer.
430 bool "Pseudo page fault support"
432 Select this option, if you want to use PFAULT pseudo page fault
433 handling under VM. If running native or in LPAR, this option
434 has no effect. If your VM does not support PFAULT, PAGEEX
435 pseudo page fault handling will be used.
436 Note that VM 4.2 supports PFAULT but has a bug in its
437 implementation that causes some problems.
438 Everybody who wants to run Linux under VM != VM4.2 should select
442 bool "VM shared kernel support"
444 Select this option, if you want to share the text segment of the
445 Linux kernel between different VM guests. This reduces memory
446 usage with lots of guests but greatly increases kernel size.
447 Also if a kernel was IPL'ed from a shared segment the kexec system
449 You should only select this option if you know what you are
450 doing and want to exploit this feature.
453 tristate "Cooperative memory management"
455 Select this option, if you want to enable the kernel interface
456 to reduce the memory size of the system. This is accomplished
457 by allocating pages of memory and put them "on hold". This only
458 makes sense for a system running under VM where the unused pages
459 will be reused by VM for other guest systems. The interface
460 allows an external monitor to balance memory of many systems.
461 Everybody who wants to run Linux under VM should select this
465 bool "/proc interface to cooperative memory management"
468 Select this option to enable the /proc interface to the
469 cooperative memory management.
472 bool "IUCV special message interface to cooperative memory management"
473 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
475 Select this option to enable the special message interface to
476 the cooperative memory management.
479 bool "Unused page notification"
481 This enables the notification of unused pages to the
482 hypervisor. The ESSA instruction is used to do the states
483 changes between a page that has content and the unused state.
486 bool "Linux - VM Monitor Stream, base infrastructure"
489 This provides a kernel interface for creating and updating z/VM APPLDATA
490 monitor records. The monitor records are updated at certain time
491 intervals, once the timer is started.
492 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
493 i.e. enables or disables monitoring on the Linux side.
494 A custom interval value (in seconds) can be written to
495 /proc/appldata/interval.
497 Defaults are 60 seconds interval and timer off.
498 The /proc entries can also be read from, showing the current settings.
501 tristate "Monitor memory management statistics"
502 depends on APPLDATA_BASE && VM_EVENT_COUNTERS
504 This provides memory management related data to the Linux - VM Monitor
505 Stream, like paging/swapping rate, memory utilisation, etc.
506 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
507 APPLDATA monitor record, i.e. enables or disables monitoring this record
511 The /proc entry can also be read from, showing the current settings.
513 This can also be compiled as a module, which will be called
517 tristate "Monitor OS statistics"
518 depends on APPLDATA_BASE
520 This provides OS related data to the Linux - VM Monitor Stream, like
521 CPU utilisation, etc.
522 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
523 APPLDATA monitor record, i.e. enables or disables monitoring this record
527 This can also be compiled as a module, which will be called
530 config APPLDATA_NET_SUM
531 tristate "Monitor overall network statistics"
532 depends on APPLDATA_BASE && NET
534 This provides network related data to the Linux - VM Monitor Stream,
535 currently there is only a total sum of network I/O statistics, no
537 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
538 APPLDATA monitor record, i.e. enables or disables monitoring this record
542 This can also be compiled as a module, which will be called
545 source kernel/Kconfig.hz
548 bool "s390 hypervisor file system support"
549 select SYS_HYPERVISOR
552 This is a virtual file system intended to provide accounting
553 information in an s390 hypervisor environment.
556 bool "kexec system call"
558 kexec is a system call that implements the ability to shutdown your
559 current kernel, and to start another kernel. It is like a reboot
560 but is independent of hardware/microcode support.
563 bool "zfcpdump support"
567 Select this option if you want to build an zfcpdump enabled kernel.
568 Refer to <file:Documentation/s390/zfcpdump.txt> for more details on this.
571 bool "s390 guest support for KVM (EXPERIMENTAL)"
572 depends on 64BIT && EXPERIMENTAL
575 select VIRTIO_CONSOLE
577 Select this option if you want to run the kernel as a guest under
578 the KVM hypervisor. This will add detection for KVM as well as a
579 virtio transport. If KVM is detected, the virtio console will be
583 bool "Enable seccomp to safely compute untrusted bytecode"
587 This kernel feature is useful for number crunching applications
588 that may need to compute untrusted bytecode during their
589 execution. By using pipes or other transports made available to
590 the process as file descriptors supporting the read/write
591 syscalls, it's possible to isolate those applications in
592 their own address space using seccomp. Once seccomp is
593 enabled via /proc/<pid>/seccomp, it cannot be disabled
594 and the task is only allowed to execute a few safe syscalls
595 defined by each seccomp mode.
601 menu "Power Management"
603 source "kernel/power/Kconfig"
615 source "drivers/Kconfig"
619 source "arch/s390/Kconfig.debug"
621 source "security/Kconfig"
623 source "crypto/Kconfig"
627 source "arch/s390/kvm/Kconfig"