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
100 source "kernel/Kconfig.freezer"
104 comment "Processor type and features"
106 source "kernel/time/Kconfig"
111 Select this option if you have a 64 bit IBM zSeries machine
112 and want to use the 64 bit addressing mode.
119 bool "Symmetric multi-processing support"
121 This enables support for systems with more than one CPU. If you have
122 a system with only one CPU, like most personal computers, say N. If
123 you have a system with more than one CPU, say Y.
125 If you say N here, the kernel will run on single and multiprocessor
126 machines, but will use only one CPU of a multiprocessor machine. If
127 you say Y here, the kernel will run on many, but not all,
128 singleprocessor machines. On a singleprocessor machine, the kernel
129 will run faster if you say N here.
131 See also the SMP-HOWTO available at
132 <http://www.tldp.org/docs.html#howto>.
134 Even if you don't know what to do here, say Y.
137 int "Maximum number of CPUs (2-64)"
140 default "32" if !64BIT
141 default "64" if 64BIT
143 This allows you to specify the maximum number of CPUs which this
144 kernel will support. The maximum supported value is 64 and the
145 minimum value which makes sense is 2.
147 This is purely to save memory - each supported CPU adds
148 approximately sixteen kilobytes to the kernel image.
151 bool "Support for hot-pluggable CPUs"
156 Say Y here to be able to turn CPUs off and on. CPUs
157 can be controlled through /sys/devices/system/cpu/cpu#.
158 Say N if you want to disable CPU hotplug.
161 bool "IEEE FPU emulation"
164 This option is required for IEEE compliant floating point arithmetic
165 on older S/390 machines. Say Y unless you know your machine doesn't
169 bool "Kernel support for 31 bit emulation"
171 select COMPAT_BINFMT_ELF
173 Select this option if you want to enable your system kernel to
174 handle system-calls from ELF binaries for 31 bit ESA. This option
175 (and some other stuff like libraries and such) is needed for
176 executing 31 bit applications. It is safe to say "Y".
178 config SYSVIPC_COMPAT
180 depends on COMPAT && SYSVIPC
187 config S390_SWITCH_AMODE
188 bool "Switch kernel/user addressing modes"
190 This option allows to switch the addressing modes of kernel and user
191 space. The kernel parameter switch_amode=on will enable this feature,
192 default is disabled. Enabling this (via kernel parameter) on machines
193 earlier than IBM System z9-109 EC/BC will reduce system performance.
195 Note that this option will also be selected by selecting the execute
196 protection option below. Enabling the execute protection via the
197 noexec kernel parameter will also switch the addressing modes,
198 independent of the switch_amode kernel parameter.
201 config S390_EXEC_PROTECT
202 bool "Data execute protection"
203 select S390_SWITCH_AMODE
205 This option allows to enable a buffer overflow protection for user
206 space programs and it also selects the addressing mode option above.
207 The kernel parameter noexec=on will enable this feature and also
208 switch the addressing modes, default is disabled. Enabling this (via
209 kernel parameter) on machines earlier than IBM System z9-109 EC/BC
210 will reduce system performance.
212 comment "Code generation options"
215 prompt "Processor type"
219 bool "S/390 model G5 and G6"
222 Select this to build a 31 bit kernel that works
223 on all S/390 and zSeries machines.
226 bool "IBM eServer zSeries model z800 and z900"
228 Select this to optimize for zSeries machines. This
229 will enable some optimizations that are not available
230 on older 31 bit only CPUs.
233 bool "IBM eServer zSeries model z890 and z990"
235 Select this enable optimizations for model z890/z990.
236 This will be slightly faster but does not work on
237 older machines such as the z900.
242 Select this to enable optimizations for IBM System z9-109, IBM
243 System z9 Enterprise Class (z9 EC), and IBM System z9 Business
244 Class (z9 BC). The kernel will be slightly faster but will not
245 work on older machines such as the z990, z890, z900, and z800.
248 bool "IBM System z10"
250 Select this to enable optimizations for IBM System z10. The
251 kernel will be slightly faster but will not work on older
252 machines such as the z990, z890, z900, z800, z9-109, z9-ec
258 bool "Pack kernel stack"
260 This option enables the compiler option -mkernel-backchain if it
261 is available. If the option is available the compiler supports
262 the new stack layout which dramatically reduces the minimum stack
263 frame size. With an old compiler a non-leaf function needs a
264 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
265 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
266 and 24 byte on 64 bit.
268 Say Y if you are unsure.
271 bool "Use 8kb for kernel stack instead of 16kb"
272 depends on PACK_STACK && 64BIT && !LOCKDEP
274 If you say Y here and the compiler supports the -mkernel-backchain
275 option the kernel will use a smaller kernel stack size. The reduced
276 size is 8kb instead of 16kb. This allows to run more threads on a
277 system and reduces the pressure on the memory management for higher
278 order page allocations.
280 Say N if you are unsure.
283 bool "Detect kernel stack overflow"
285 This option enables the compiler option -mstack-guard and
286 -mstack-size if they are available. If the compiler supports them
287 it will emit additional code to each function prolog to trigger
288 an illegal operation if the kernel stack is about to overflow.
290 Say N if you are unsure.
293 int "Size of the guard area (128-1024)"
295 depends on CHECK_STACK
298 This allows you to specify the size of the guard area at the lower
299 end of the kernel stack. If the kernel stack points into the guard
300 area on function entry an illegal operation is triggered. The size
301 needs to be a power of 2. Please keep in mind that the size of an
302 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
303 The minimum size for the stack guard should be 256 for 31 bit and
307 bool "Emit compiler warnings for function with broken stack usage"
309 This option enables the compiler options -mwarn-framesize and
310 -mwarn-dynamicstack. If the compiler supports these options it
311 will generate warnings for function which either use alloca or
312 create a stack frame bigger than CONFIG_WARN_STACK_SIZE.
314 Say N if you are unsure.
316 config WARN_STACK_SIZE
317 int "Maximum frame size considered safe (128-2048)"
319 depends on WARN_STACK
322 This allows you to specify the maximum frame size a function may
323 have without the compiler complaining about it.
325 config ARCH_POPULATES_NODE_MAP
328 comment "Kernel preemption"
330 source "kernel/Kconfig.preempt"
332 config ARCH_SPARSEMEM_ENABLE
334 select SPARSEMEM_VMEMMAP_ENABLE
335 select SPARSEMEM_VMEMMAP
336 select SPARSEMEM_STATIC if !64BIT
338 config ARCH_SPARSEMEM_DEFAULT
341 config ARCH_SELECT_MEMORY_MODEL
344 config ARCH_ENABLE_MEMORY_HOTPLUG
348 config ARCH_ENABLE_MEMORY_HOTREMOVE
353 comment "I/O subsystem configuration"
356 tristate "QDIO support"
358 This driver provides the Queued Direct I/O base support for
361 To compile this driver as a module, choose M here: the
362 module will be called qdio.
367 tristate "Support for CHSC subchannels"
369 This driver allows usage of CHSC subchannels. A CHSC subchannel
370 is usually present on LPAR only.
371 The driver creates a device /dev/chsc, which may be used to
372 obtain I/O configuration information about the machine and
373 to issue asynchronous chsc commands (DANGEROUS).
374 You will usually only want to use this interface on a special
375 LPAR designated for system management.
377 To compile this driver as a module, choose M here: the
378 module will be called chsc_sch.
385 bool "Builtin IPL record support"
387 If you want to use the produced kernel to IPL directly from a
388 device, you have to merge a bootsector specific to the device
389 into the first bytes of the kernel. You will have to select the
393 prompt "IPL method generated into head.S"
397 Select "tape" if you want to IPL the image from a Tape.
399 Select "vm_reader" if you are running under VM/ESA and want
400 to IPL the image from the emulated card reader.
410 source "fs/Kconfig.binfmt"
412 config FORCE_MAX_ZONEORDER
417 bool "Show crashed user process info"
419 Say Y to print all process fault locations to the console. This is
420 a debugging option; you probably do not want to set it unless you
421 are an S390 port maintainer.
424 bool "Pseudo page fault support"
426 Select this option, if you want to use PFAULT pseudo page fault
427 handling under VM. If running native or in LPAR, this option
428 has no effect. If your VM does not support PFAULT, PAGEEX
429 pseudo page fault handling will be used.
430 Note that VM 4.2 supports PFAULT but has a bug in its
431 implementation that causes some problems.
432 Everybody who wants to run Linux under VM != VM4.2 should select
436 bool "VM shared kernel support"
438 Select this option, if you want to share the text segment of the
439 Linux kernel between different VM guests. This reduces memory
440 usage with lots of guests but greatly increases kernel size.
441 Also if a kernel was IPL'ed from a shared segment the kexec system
443 You should only select this option if you know what you are
444 doing and want to exploit this feature.
447 tristate "Cooperative memory management"
449 Select this option, if you want to enable the kernel interface
450 to reduce the memory size of the system. This is accomplished
451 by allocating pages of memory and put them "on hold". This only
452 makes sense for a system running under VM where the unused pages
453 will be reused by VM for other guest systems. The interface
454 allows an external monitor to balance memory of many systems.
455 Everybody who wants to run Linux under VM should select this
459 bool "/proc interface to cooperative memory management"
462 Select this option to enable the /proc interface to the
463 cooperative memory management.
466 bool "IUCV special message interface to cooperative memory management"
467 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
469 Select this option to enable the special message interface to
470 the cooperative memory management.
473 bool "Unused page notification"
475 This enables the notification of unused pages to the
476 hypervisor. The ESSA instruction is used to do the states
477 changes between a page that has content and the unused state.
480 bool "Linux - VM Monitor Stream, base infrastructure"
483 This provides a kernel interface for creating and updating z/VM APPLDATA
484 monitor records. The monitor records are updated at certain time
485 intervals, once the timer is started.
486 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
487 i.e. enables or disables monitoring on the Linux side.
488 A custom interval value (in seconds) can be written to
489 /proc/appldata/interval.
491 Defaults are 60 seconds interval and timer off.
492 The /proc entries can also be read from, showing the current settings.
495 tristate "Monitor memory management statistics"
496 depends on APPLDATA_BASE && VM_EVENT_COUNTERS
498 This provides memory management related data to the Linux - VM Monitor
499 Stream, like paging/swapping rate, memory utilisation, etc.
500 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
501 APPLDATA monitor record, i.e. enables or disables monitoring this record
505 The /proc entry can also be read from, showing the current settings.
507 This can also be compiled as a module, which will be called
511 tristate "Monitor OS statistics"
512 depends on APPLDATA_BASE
514 This provides OS related data to the Linux - VM Monitor Stream, like
515 CPU utilisation, etc.
516 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
517 APPLDATA monitor record, i.e. enables or disables monitoring this record
521 This can also be compiled as a module, which will be called
524 config APPLDATA_NET_SUM
525 tristate "Monitor overall network statistics"
526 depends on APPLDATA_BASE && NET
528 This provides network related data to the Linux - VM Monitor Stream,
529 currently there is only a total sum of network I/O statistics, no
531 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
532 APPLDATA monitor record, i.e. enables or disables monitoring this record
536 This can also be compiled as a module, which will be called
539 source kernel/Kconfig.hz
542 bool "s390 hypervisor file system support"
543 select SYS_HYPERVISOR
546 This is a virtual file system intended to provide accounting
547 information in an s390 hypervisor environment.
550 bool "kexec system call"
552 kexec is a system call that implements the ability to shutdown your
553 current kernel, and to start another kernel. It is like a reboot
554 but is independent of hardware/microcode support.
557 bool "zfcpdump support"
561 Select this option if you want to build an zfcpdump enabled kernel.
562 Refer to <file:Documentation/s390/zfcpdump.txt> for more details on this.
565 bool "s390 guest support for KVM (EXPERIMENTAL)"
566 depends on 64BIT && EXPERIMENTAL
569 select VIRTIO_CONSOLE
571 Select this option if you want to run the kernel as a guest under
572 the KVM hypervisor. This will add detection for KVM as well as a
573 virtio transport. If KVM is detected, the virtio console will be
577 bool "Enable seccomp to safely compute untrusted bytecode"
581 This kernel feature is useful for number crunching applications
582 that may need to compute untrusted bytecode during their
583 execution. By using pipes or other transports made available to
584 the process as file descriptors supporting the read/write
585 syscalls, it's possible to isolate those applications in
586 their own address space using seccomp. Once seccomp is
587 enabled via /proc/<pid>/seccomp, it cannot be disabled
588 and the task is only allowed to execute a few safe syscalls
589 defined by each seccomp mode.
603 source "drivers/Kconfig"
607 source "arch/s390/Kconfig.debug"
609 source "security/Kconfig"
611 source "crypto/Kconfig"
615 source "arch/s390/kvm/Kconfig"
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