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
99 config SCHED_OMIT_FRAME_POINTER
103 source "init/Kconfig"
105 source "kernel/Kconfig.freezer"
109 comment "Processor type and features"
111 source "kernel/time/Kconfig"
116 Select this option if you have a 64 bit IBM zSeries machine
117 and want to use the 64 bit addressing mode.
124 bool "Symmetric multi-processing support"
126 This enables support for systems with more than one CPU. If you have
127 a system with only one CPU, like most personal computers, say N. If
128 you have a system with more than one CPU, say Y.
130 If you say N here, the kernel will run on single and multiprocessor
131 machines, but will use only one CPU of a multiprocessor machine. If
132 you say Y here, the kernel will run on many, but not all,
133 singleprocessor machines. On a singleprocessor machine, the kernel
134 will run faster if you say N here.
136 See also the SMP-HOWTO available at
137 <http://www.tldp.org/docs.html#howto>.
139 Even if you don't know what to do here, say Y.
142 int "Maximum number of CPUs (2-64)"
145 default "32" if !64BIT
146 default "64" if 64BIT
148 This allows you to specify the maximum number of CPUs which this
149 kernel will support. The maximum supported value is 64 and the
150 minimum value which makes sense is 2.
152 This is purely to save memory - each supported CPU adds
153 approximately sixteen kilobytes to the kernel image.
156 bool "Support for hot-pluggable CPUs"
161 Say Y here to be able to turn CPUs off and on. CPUs
162 can be controlled through /sys/devices/system/cpu/cpu#.
163 Say N if you want to disable CPU hotplug.
166 bool "IEEE FPU emulation"
169 This option is required for IEEE compliant floating point arithmetic
170 on older S/390 machines. Say Y unless you know your machine doesn't
174 bool "Kernel support for 31 bit emulation"
176 select COMPAT_BINFMT_ELF
178 Select this option if you want to enable your system kernel to
179 handle system-calls from ELF binaries for 31 bit ESA. This option
180 (and some other stuff like libraries and such) is needed for
181 executing 31 bit applications. It is safe to say "Y".
183 config SYSVIPC_COMPAT
185 depends on COMPAT && SYSVIPC
192 config S390_SWITCH_AMODE
193 bool "Switch kernel/user addressing modes"
195 This option allows to switch the addressing modes of kernel and user
196 space. The kernel parameter switch_amode=on will enable this feature,
197 default is disabled. Enabling this (via kernel parameter) on machines
198 earlier than IBM System z9-109 EC/BC will reduce system performance.
200 Note that this option will also be selected by selecting the execute
201 protection option below. Enabling the execute protection via the
202 noexec kernel parameter will also switch the addressing modes,
203 independent of the switch_amode kernel parameter.
206 config S390_EXEC_PROTECT
207 bool "Data execute protection"
208 select S390_SWITCH_AMODE
210 This option allows to enable a buffer overflow protection for user
211 space programs and it also selects the addressing mode option above.
212 The kernel parameter noexec=on will enable this feature and also
213 switch the addressing modes, default is disabled. Enabling this (via
214 kernel parameter) on machines earlier than IBM System z9-109 EC/BC
215 will reduce system performance.
217 comment "Code generation options"
220 prompt "Processor type"
224 bool "S/390 model G5 and G6"
227 Select this to build a 31 bit kernel that works
228 on all S/390 and zSeries machines.
231 bool "IBM eServer zSeries model z800 and z900"
233 Select this to optimize for zSeries machines. This
234 will enable some optimizations that are not available
235 on older 31 bit only CPUs.
238 bool "IBM eServer zSeries model z890 and z990"
240 Select this enable optimizations for model z890/z990.
241 This will be slightly faster but does not work on
242 older machines such as the z900.
247 Select this to enable optimizations for IBM System z9-109, IBM
248 System z9 Enterprise Class (z9 EC), and IBM System z9 Business
249 Class (z9 BC). The kernel will be slightly faster but will not
250 work on older machines such as the z990, z890, z900, and z800.
253 bool "IBM System z10"
255 Select this to enable optimizations for IBM System z10. The
256 kernel will be slightly faster but will not work on older
257 machines such as the z990, z890, z900, z800, z9-109, z9-ec
263 bool "Pack kernel stack"
265 This option enables the compiler option -mkernel-backchain if it
266 is available. If the option is available the compiler supports
267 the new stack layout which dramatically reduces the minimum stack
268 frame size. With an old compiler a non-leaf function needs a
269 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
270 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
271 and 24 byte on 64 bit.
273 Say Y if you are unsure.
276 bool "Use 8kb for kernel stack instead of 16kb"
277 depends on PACK_STACK && 64BIT && !LOCKDEP
279 If you say Y here and the compiler supports the -mkernel-backchain
280 option the kernel will use a smaller kernel stack size. The reduced
281 size is 8kb instead of 16kb. This allows to run more threads on a
282 system and reduces the pressure on the memory management for higher
283 order page allocations.
285 Say N if you are unsure.
288 bool "Detect kernel stack overflow"
290 This option enables the compiler option -mstack-guard and
291 -mstack-size if they are available. If the compiler supports them
292 it will emit additional code to each function prolog to trigger
293 an illegal operation if the kernel stack is about to overflow.
295 Say N if you are unsure.
298 int "Size of the guard area (128-1024)"
300 depends on CHECK_STACK
303 This allows you to specify the size of the guard area at the lower
304 end of the kernel stack. If the kernel stack points into the guard
305 area on function entry an illegal operation is triggered. The size
306 needs to be a power of 2. Please keep in mind that the size of an
307 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
308 The minimum size for the stack guard should be 256 for 31 bit and
312 bool "Emit compiler warnings for function with broken stack usage"
314 This option enables the compiler options -mwarn-framesize and
315 -mwarn-dynamicstack. If the compiler supports these options it
316 will generate warnings for function which either use alloca or
317 create a stack frame bigger than CONFIG_WARN_STACK_SIZE.
319 Say N if you are unsure.
321 config WARN_STACK_SIZE
322 int "Maximum frame size considered safe (128-2048)"
324 depends on WARN_STACK
327 This allows you to specify the maximum frame size a function may
328 have without the compiler complaining about it.
330 config ARCH_POPULATES_NODE_MAP
333 comment "Kernel preemption"
335 source "kernel/Kconfig.preempt"
337 config ARCH_SPARSEMEM_ENABLE
339 select SPARSEMEM_VMEMMAP_ENABLE
340 select SPARSEMEM_VMEMMAP
341 select SPARSEMEM_STATIC if !64BIT
343 config ARCH_SPARSEMEM_DEFAULT
346 config ARCH_SELECT_MEMORY_MODEL
349 config ARCH_ENABLE_MEMORY_HOTPLUG
353 config ARCH_ENABLE_MEMORY_HOTREMOVE
356 config ARCH_HIBERNATION_POSSIBLE
361 comment "I/O subsystem configuration"
364 tristate "QDIO support"
366 This driver provides the Queued Direct I/O base support for
369 To compile this driver as a module, choose M here: the
370 module will be called qdio.
375 tristate "Support for CHSC subchannels"
377 This driver allows usage of CHSC subchannels. A CHSC subchannel
378 is usually present on LPAR only.
379 The driver creates a device /dev/chsc, which may be used to
380 obtain I/O configuration information about the machine and
381 to issue asynchronous chsc commands (DANGEROUS).
382 You will usually only want to use this interface on a special
383 LPAR designated for system management.
385 To compile this driver as a module, choose M here: the
386 module will be called chsc_sch.
393 bool "Builtin IPL record support"
395 If you want to use the produced kernel to IPL directly from a
396 device, you have to merge a bootsector specific to the device
397 into the first bytes of the kernel. You will have to select the
401 prompt "IPL method generated into head.S"
405 Select "tape" if you want to IPL the image from a Tape.
407 Select "vm_reader" if you are running under VM/ESA and want
408 to IPL the image from the emulated card reader.
418 source "fs/Kconfig.binfmt"
420 config FORCE_MAX_ZONEORDER
425 bool "Show crashed user process info"
427 Say Y to print all process fault locations to the console. This is
428 a debugging option; you probably do not want to set it unless you
429 are an S390 port maintainer.
432 bool "Pseudo page fault support"
434 Select this option, if you want to use PFAULT pseudo page fault
435 handling under VM. If running native or in LPAR, this option
436 has no effect. If your VM does not support PFAULT, PAGEEX
437 pseudo page fault handling will be used.
438 Note that VM 4.2 supports PFAULT but has a bug in its
439 implementation that causes some problems.
440 Everybody who wants to run Linux under VM != VM4.2 should select
444 bool "VM shared kernel support"
446 Select this option, if you want to share the text segment of the
447 Linux kernel between different VM guests. This reduces memory
448 usage with lots of guests but greatly increases kernel size.
449 Also if a kernel was IPL'ed from a shared segment the kexec system
451 You should only select this option if you know what you are
452 doing and want to exploit this feature.
455 tristate "Cooperative memory management"
457 Select this option, if you want to enable the kernel interface
458 to reduce the memory size of the system. This is accomplished
459 by allocating pages of memory and put them "on hold". This only
460 makes sense for a system running under VM where the unused pages
461 will be reused by VM for other guest systems. The interface
462 allows an external monitor to balance memory of many systems.
463 Everybody who wants to run Linux under VM should select this
467 bool "/proc interface to cooperative memory management"
470 Select this option to enable the /proc interface to the
471 cooperative memory management.
474 bool "IUCV special message interface to cooperative memory management"
475 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
477 Select this option to enable the special message interface to
478 the cooperative memory management.
481 bool "Unused page notification"
483 This enables the notification of unused pages to the
484 hypervisor. The ESSA instruction is used to do the states
485 changes between a page that has content and the unused state.
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"