1
2config ARCH_HAS_MEM_ENCRYPT
3 def_bool y
4
5config MMU
6 def_bool y
7
8config ZONE_DMA
9 def_bool y
10
11config CPU_BIG_ENDIAN
12 def_bool y
13
14config LOCKDEP_SUPPORT
15 def_bool y
16
17config STACKTRACE_SUPPORT
18 def_bool y
19
20config ARCH_HAS_ILOG2_U32
21 def_bool n
22
23config ARCH_HAS_ILOG2_U64
24 def_bool n
25
26config GENERIC_HWEIGHT
27 def_bool y
28
29config GENERIC_BUG
30 def_bool y if BUG
31
32config GENERIC_BUG_RELATIVE_POINTERS
33 def_bool y
34
35config GENERIC_LOCKBREAK
36 def_bool y if PREEMPT
37
38config PGSTE
39 def_bool y if KVM
40
41config ARCH_SUPPORTS_DEBUG_PAGEALLOC
42 def_bool y
43
44config AUDIT_ARCH
45 def_bool y
46
47config NO_IOPORT_MAP
48 def_bool y
49
50config PCI_QUIRKS
51 def_bool n
52
53config ARCH_SUPPORTS_UPROBES
54 def_bool y
55
56config KASAN_SHADOW_OFFSET
57 hex
58 depends on KASAN
59 default 0x18000000000000 if KASAN_S390_4_LEVEL_PAGING
60 default 0x30000000000
61
62config S390
63 def_bool y
64 select ARCH_BINFMT_ELF_STATE
65 select ARCH_HAS_DEVMEM_IS_ALLOWED
66 select ARCH_HAS_ELF_RANDOMIZE
67 select ARCH_HAS_FORTIFY_SOURCE
68 select ARCH_HAS_GCOV_PROFILE_ALL
69 select ARCH_HAS_GIGANTIC_PAGE
70 select ARCH_HAS_KCOV
71 select ARCH_HAS_PTE_SPECIAL
72 select ARCH_HAS_SET_MEMORY
73 select ARCH_HAS_STRICT_KERNEL_RWX
74 select ARCH_HAS_STRICT_MODULE_RWX
75 select ARCH_HAS_SYSCALL_WRAPPER
76 select ARCH_HAS_UBSAN_SANITIZE_ALL
77 select ARCH_HAVE_NMI_SAFE_CMPXCHG
78 select ARCH_INLINE_READ_LOCK
79 select ARCH_INLINE_READ_LOCK_BH
80 select ARCH_INLINE_READ_LOCK_IRQ
81 select ARCH_INLINE_READ_LOCK_IRQSAVE
82 select ARCH_INLINE_READ_TRYLOCK
83 select ARCH_INLINE_READ_UNLOCK
84 select ARCH_INLINE_READ_UNLOCK_BH
85 select ARCH_INLINE_READ_UNLOCK_IRQ
86 select ARCH_INLINE_READ_UNLOCK_IRQRESTORE
87 select ARCH_INLINE_SPIN_LOCK
88 select ARCH_INLINE_SPIN_LOCK_BH
89 select ARCH_INLINE_SPIN_LOCK_IRQ
90 select ARCH_INLINE_SPIN_LOCK_IRQSAVE
91 select ARCH_INLINE_SPIN_TRYLOCK
92 select ARCH_INLINE_SPIN_TRYLOCK_BH
93 select ARCH_INLINE_SPIN_UNLOCK
94 select ARCH_INLINE_SPIN_UNLOCK_BH
95 select ARCH_INLINE_SPIN_UNLOCK_IRQ
96 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE
97 select ARCH_INLINE_WRITE_LOCK
98 select ARCH_INLINE_WRITE_LOCK_BH
99 select ARCH_INLINE_WRITE_LOCK_IRQ
100 select ARCH_INLINE_WRITE_LOCK_IRQSAVE
101 select ARCH_INLINE_WRITE_TRYLOCK
102 select ARCH_INLINE_WRITE_UNLOCK
103 select ARCH_INLINE_WRITE_UNLOCK_BH
104 select ARCH_INLINE_WRITE_UNLOCK_IRQ
105 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
106 select ARCH_KEEP_MEMBLOCK
107 select ARCH_SAVE_PAGE_KEYS if HIBERNATION
108 select ARCH_SUPPORTS_ATOMIC_RMW
109 select ARCH_SUPPORTS_NUMA_BALANCING
110 select ARCH_USE_BUILTIN_BSWAP
111 select ARCH_USE_CMPXCHG_LOCKREF
112 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
113 select ARCH_WANT_IPC_PARSE_VERSION
114 select BUILDTIME_EXTABLE_SORT
115 select CLONE_BACKWARDS2
116 select DYNAMIC_FTRACE if FUNCTION_TRACER
117 select GENERIC_CLOCKEVENTS
118 select GENERIC_CPU_AUTOPROBE
119 select GENERIC_CPU_VULNERABILITIES
120 select GENERIC_FIND_FIRST_BIT
121 select GENERIC_SMP_IDLE_THREAD
122 select GENERIC_TIME_VSYSCALL
123 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
124 select HAVE_ARCH_AUDITSYSCALL
125 select HAVE_ARCH_JUMP_LABEL
126 select HAVE_ARCH_JUMP_LABEL_RELATIVE
127 select HAVE_ARCH_KASAN
128 select CPU_NO_EFFICIENT_FFS if !HAVE_MARCH_Z9_109_FEATURES
129 select HAVE_ARCH_SECCOMP_FILTER
130 select HAVE_ARCH_SOFT_DIRTY
131 select HAVE_ARCH_TRACEHOOK
132 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
133 select HAVE_ARCH_VMAP_STACK
134 select HAVE_EBPF_JIT if PACK_STACK && HAVE_MARCH_Z196_FEATURES
135 select HAVE_CMPXCHG_DOUBLE
136 select HAVE_CMPXCHG_LOCAL
137 select HAVE_COPY_THREAD_TLS
138 select HAVE_DEBUG_KMEMLEAK
139 select HAVE_DMA_CONTIGUOUS
140 select HAVE_DYNAMIC_FTRACE
141 select HAVE_DYNAMIC_FTRACE_WITH_REGS
142 select HAVE_FAST_GUP
143 select HAVE_EFFICIENT_UNALIGNED_ACCESS
144 select HAVE_FENTRY
145 select HAVE_FTRACE_MCOUNT_RECORD
146 select HAVE_FUNCTION_GRAPH_TRACER
147 select HAVE_FUNCTION_TRACER
148 select HAVE_FUTEX_CMPXCHG if FUTEX
149 select HAVE_GCC_PLUGINS
150 select HAVE_KERNEL_BZIP2
151 select HAVE_KERNEL_GZIP
152 select HAVE_KERNEL_LZ4
153 select HAVE_KERNEL_LZMA
154 select HAVE_KERNEL_LZO
155 select HAVE_KERNEL_UNCOMPRESSED
156 select HAVE_KERNEL_XZ
157 select HAVE_KPROBES
158 select HAVE_KRETPROBES
159 select HAVE_KVM
160 select HAVE_LIVEPATCH
161 select HAVE_PERF_REGS
162 select HAVE_PERF_USER_STACK_DUMP
163 select HAVE_MEMBLOCK_NODE_MAP
164 select HAVE_MEMBLOCK_PHYS_MAP
165 select HAVE_MMU_GATHER_NO_GATHER
166 select HAVE_MOD_ARCH_SPECIFIC
167 select HAVE_NOP_MCOUNT
168 select HAVE_OPROFILE
169 select HAVE_PCI
170 select HAVE_PERF_EVENTS
171 select HAVE_RCU_TABLE_FREE
172 select HAVE_REGS_AND_STACK_ACCESS_API
173 select HAVE_RSEQ
174 select HAVE_SYSCALL_TRACEPOINTS
175 select HAVE_VIRT_CPU_ACCOUNTING
176 select IOMMU_HELPER if PCI
177 select IOMMU_SUPPORT if PCI
178 select MODULES_USE_ELF_RELA
179 select NEED_DMA_MAP_STATE if PCI
180 select NEED_SG_DMA_LENGTH if PCI
181 select OLD_SIGACTION
182 select OLD_SIGSUSPEND3
183 select PCI_DOMAINS if PCI
184 select PCI_MSI if PCI
185 select SPARSE_IRQ
186 select SYSCTL_EXCEPTION_TRACE
187 select THREAD_INFO_IN_TASK
188 select TTY
189 select VIRT_CPU_ACCOUNTING
190 select ARCH_HAS_SCALED_CPUTIME
191 select HAVE_NMI
192 select ARCH_HAS_FORCE_DMA_UNENCRYPTED
193 select SWIOTLB
194 select GENERIC_ALLOCATOR
195
196
197config SCHED_OMIT_FRAME_POINTER
198 def_bool y
199
200config PGTABLE_LEVELS
201 int
202 default 5
203
204source "kernel/livepatch/Kconfig"
205
206menu "Processor type and features"
207
208config HAVE_MARCH_Z900_FEATURES
209 def_bool n
210
211config HAVE_MARCH_Z990_FEATURES
212 def_bool n
213 select HAVE_MARCH_Z900_FEATURES
214
215config HAVE_MARCH_Z9_109_FEATURES
216 def_bool n
217 select HAVE_MARCH_Z990_FEATURES
218
219config HAVE_MARCH_Z10_FEATURES
220 def_bool n
221 select HAVE_MARCH_Z9_109_FEATURES
222
223config HAVE_MARCH_Z196_FEATURES
224 def_bool n
225 select HAVE_MARCH_Z10_FEATURES
226
227config HAVE_MARCH_ZEC12_FEATURES
228 def_bool n
229 select HAVE_MARCH_Z196_FEATURES
230
231config HAVE_MARCH_Z13_FEATURES
232 def_bool n
233 select HAVE_MARCH_ZEC12_FEATURES
234
235config HAVE_MARCH_Z14_FEATURES
236 def_bool n
237 select HAVE_MARCH_Z13_FEATURES
238
239choice
240 prompt "Processor type"
241 default MARCH_Z196
242
243config MARCH_Z900
244 bool "IBM zSeries model z800 and z900"
245 depends on !CC_IS_CLANG
246 select HAVE_MARCH_Z900_FEATURES
247 help
248 Select this to enable optimizations for model z800/z900 (2064 and
249 2066 series). This will enable some optimizations that are not
250 available on older ESA/390 (31 Bit) only CPUs.
251
252config MARCH_Z990
253 bool "IBM zSeries model z890 and z990"
254 depends on !CC_IS_CLANG
255 select HAVE_MARCH_Z990_FEATURES
256 help
257 Select this to enable optimizations for model z890/z990 (2084 and
258 2086 series). The kernel will be slightly faster but will not work
259 on older machines.
260
261config MARCH_Z9_109
262 bool "IBM System z9"
263 depends on !CC_IS_CLANG
264 select HAVE_MARCH_Z9_109_FEATURES
265 help
266 Select this to enable optimizations for IBM System z9 (2094 and
267 2096 series). The kernel will be slightly faster but will not work
268 on older machines.
269
270config MARCH_Z10
271 bool "IBM System z10"
272 select HAVE_MARCH_Z10_FEATURES
273 help
274 Select this to enable optimizations for IBM System z10 (2097 and
275 2098 series). The kernel will be slightly faster but will not work
276 on older machines.
277
278config MARCH_Z196
279 bool "IBM zEnterprise 114 and 196"
280 select HAVE_MARCH_Z196_FEATURES
281 help
282 Select this to enable optimizations for IBM zEnterprise 114 and 196
283 (2818 and 2817 series). The kernel will be slightly faster but will
284 not work on older machines.
285
286config MARCH_ZEC12
287 bool "IBM zBC12 and zEC12"
288 select HAVE_MARCH_ZEC12_FEATURES
289 help
290 Select this to enable optimizations for IBM zBC12 and zEC12 (2828 and
291 2827 series). The kernel will be slightly faster but will not work on
292 older machines.
293
294config MARCH_Z13
295 bool "IBM z13s and z13"
296 select HAVE_MARCH_Z13_FEATURES
297 help
298 Select this to enable optimizations for IBM z13s and z13 (2965 and
299 2964 series). The kernel will be slightly faster but will not work on
300 older machines.
301
302config MARCH_Z14
303 bool "IBM z14 ZR1 and z14"
304 select HAVE_MARCH_Z14_FEATURES
305 help
306 Select this to enable optimizations for IBM z14 ZR1 and z14 (3907
307 and 3906 series). The kernel will be slightly faster but will not
308 work on older machines.
309
310endchoice
311
312config MARCH_Z900_TUNE
313 def_bool TUNE_Z900 || MARCH_Z900 && TUNE_DEFAULT
314
315config MARCH_Z990_TUNE
316 def_bool TUNE_Z990 || MARCH_Z990 && TUNE_DEFAULT
317
318config MARCH_Z9_109_TUNE
319 def_bool TUNE_Z9_109 || MARCH_Z9_109 && TUNE_DEFAULT
320
321config MARCH_Z10_TUNE
322 def_bool TUNE_Z10 || MARCH_Z10 && TUNE_DEFAULT
323
324config MARCH_Z196_TUNE
325 def_bool TUNE_Z196 || MARCH_Z196 && TUNE_DEFAULT
326
327config MARCH_ZEC12_TUNE
328 def_bool TUNE_ZEC12 || MARCH_ZEC12 && TUNE_DEFAULT
329
330config MARCH_Z13_TUNE
331 def_bool TUNE_Z13 || MARCH_Z13 && TUNE_DEFAULT
332
333config MARCH_Z14_TUNE
334 def_bool TUNE_Z14 || MARCH_Z14 && TUNE_DEFAULT
335
336choice
337 prompt "Tune code generation"
338 default TUNE_DEFAULT
339 help
340 Cause the compiler to tune (-mtune) the generated code for a machine.
341 This will make the code run faster on the selected machine but
342 somewhat slower on other machines.
343 This option only changes how the compiler emits instructions, not the
344 selection of instructions itself, so the resulting kernel will run on
345 all other machines.
346
347config TUNE_DEFAULT
348 bool "Default"
349 help
350 Tune the generated code for the target processor for which the kernel
351 will be compiled.
352
353config TUNE_Z900
354 bool "IBM zSeries model z800 and z900"
355 depends on !CC_IS_CLANG
356
357config TUNE_Z990
358 bool "IBM zSeries model z890 and z990"
359 depends on !CC_IS_CLANG
360
361config TUNE_Z9_109
362 bool "IBM System z9"
363 depends on !CC_IS_CLANG
364
365config TUNE_Z10
366 bool "IBM System z10"
367
368config TUNE_Z196
369 bool "IBM zEnterprise 114 and 196"
370
371config TUNE_ZEC12
372 bool "IBM zBC12 and zEC12"
373
374config TUNE_Z13
375 bool "IBM z13"
376
377config TUNE_Z14
378 bool "IBM z14"
379
380endchoice
381
382config 64BIT
383 def_bool y
384
385config COMPAT
386 def_bool y
387 prompt "Kernel support for 31 bit emulation"
388 select COMPAT_BINFMT_ELF if BINFMT_ELF
389 select ARCH_WANT_OLD_COMPAT_IPC
390 select COMPAT_OLD_SIGACTION
391 select HAVE_UID16
392 depends on MULTIUSER
393 help
394 Select this option if you want to enable your system kernel to
395 handle system-calls from ELF binaries for 31 bit ESA. This option
396 (and some other stuff like libraries and such) is needed for
397 executing 31 bit applications. It is safe to say "Y".
398
399config COMPAT_VDSO
400 def_bool COMPAT && !CC_IS_CLANG
401
402config SYSVIPC_COMPAT
403 def_bool y if COMPAT && SYSVIPC
404
405config SMP
406 def_bool y
407
408config NR_CPUS
409 int "Maximum number of CPUs (2-512)"
410 range 2 512
411 default "64"
412 help
413 This allows you to specify the maximum number of CPUs which this
414 kernel will support. The maximum supported value is 512 and the
415 minimum value which makes sense is 2.
416
417 This is purely to save memory - each supported CPU adds
418 approximately sixteen kilobytes to the kernel image.
419
420config HOTPLUG_CPU
421 def_bool y
422
423
424
425
426
427
428config NODES_SPAN_OTHER_NODES
429 def_bool NUMA
430
431config NUMA
432 bool "NUMA support"
433 depends on SCHED_TOPOLOGY
434 default n
435 help
436 Enable NUMA support
437
438 This option adds NUMA support to the kernel.
439
440 An operation mode can be selected by appending
441 numa=<method> to the kernel command line.
442
443 The default behaviour is identical to appending numa=plain to
444 the command line. This will create just one node with all
445 available memory and all CPUs in it.
446
447config NODES_SHIFT
448 int "Maximum NUMA nodes (as a power of 2)"
449 range 1 10
450 depends on NUMA
451 default "4"
452 help
453 Specify the maximum number of NUMA nodes available on the target
454 system. Increases memory reserved to accommodate various tables.
455
456menu "Select NUMA modes"
457 depends on NUMA
458
459config NUMA_EMU
460 bool "NUMA emulation"
461 default y
462 help
463 Numa emulation mode will split the available system memory into
464 equal chunks which then are distributed over the configured number
465 of nodes in a round-robin manner.
466
467 The number of fake nodes is limited by the number of available memory
468 chunks (i.e. memory size / fake size) and the number of supported
469 nodes in the kernel.
470
471 The CPUs are assigned to the nodes in a way that partially respects
472 the original machine topology (if supported by the machine).
473 Fair distribution of the CPUs is not guaranteed.
474
475config EMU_SIZE
476 hex "NUMA emulation memory chunk size"
477 default 0x10000000
478 range 0x400000 0x100000000
479 depends on NUMA_EMU
480 help
481 Select the default size by which the memory is chopped and then
482 assigned to emulated NUMA nodes.
483
484 This can be overridden by specifying
485
486 emu_size=<n>
487
488 on the kernel command line where also suffixes K, M, G, and T are
489 supported.
490
491endmenu
492
493config SCHED_SMT
494 def_bool n
495
496config SCHED_MC
497 def_bool n
498
499config SCHED_BOOK
500 def_bool n
501
502config SCHED_DRAWER
503 def_bool n
504
505config SCHED_TOPOLOGY
506 def_bool y
507 prompt "Topology scheduler support"
508 select SCHED_SMT
509 select SCHED_MC
510 select SCHED_BOOK
511 select SCHED_DRAWER
512 help
513 Topology scheduler support improves the CPU scheduler's decision
514 making when dealing with machines that have multi-threading,
515 multiple cores or multiple books.
516
517source "kernel/Kconfig.hz"
518
519config KEXEC
520 def_bool y
521 select KEXEC_CORE
522
523config KEXEC_FILE
524 bool "kexec file based system call"
525 select KEXEC_CORE
526 select BUILD_BIN2C
527 depends on CRYPTO
528 depends on CRYPTO_SHA256
529 depends on CRYPTO_SHA256_S390
530 help
531 Enable the kexec file based system call. In contrast to the normal
532 kexec system call this system call takes file descriptors for the
533 kernel and initramfs as arguments.
534
535config ARCH_HAS_KEXEC_PURGATORY
536 def_bool y
537 depends on KEXEC_FILE
538
539config KEXEC_VERIFY_SIG
540 bool "Verify kernel signature during kexec_file_load() syscall"
541 depends on KEXEC_FILE && SYSTEM_DATA_VERIFICATION
542 help
543 This option makes kernel signature verification mandatory for
544 the kexec_file_load() syscall.
545
546 In addition to that option, you need to enable signature
547 verification for the corresponding kernel image type being
548 loaded in order for this to work.
549
550config ARCH_RANDOM
551 def_bool y
552 prompt "s390 architectural random number generation API"
553 help
554 Enable the s390 architectural random number generation API
555 to provide random data for all consumers within the Linux
556 kernel.
557
558 When enabled the arch_random_* functions declared in linux/random.h
559 are implemented. The implementation is based on the s390 CPACF
560 instruction subfunction TRNG which provides a real true random
561 number generator.
562
563 If unsure, say Y.
564
565config KERNEL_NOBP
566 def_bool n
567 prompt "Enable modified branch prediction for the kernel by default"
568 help
569 If this option is selected the kernel will switch to a modified
570 branch prediction mode if the firmware interface is available.
571 The modified branch prediction mode improves the behaviour in
572 regard to speculative execution.
573
574 With the option enabled the kernel parameter "nobp=0" or "nospec"
575 can be used to run the kernel in the normal branch prediction mode.
576
577 With the option disabled the modified branch prediction mode is
578 enabled with the "nobp=1" kernel parameter.
579
580 If unsure, say N.
581
582config EXPOLINE
583 def_bool n
584 prompt "Avoid speculative indirect branches in the kernel"
585 help
586 Compile the kernel with the expoline compiler options to guard
587 against kernel-to-user data leaks by avoiding speculative indirect
588 branches.
589 Requires a compiler with -mindirect-branch=thunk support for full
590 protection. The kernel may run slower.
591
592 If unsure, say N.
593
594choice
595 prompt "Expoline default"
596 depends on EXPOLINE
597 default EXPOLINE_FULL
598
599config EXPOLINE_OFF
600 bool "spectre_v2=off"
601
602config EXPOLINE_AUTO
603 bool "spectre_v2=auto"
604
605config EXPOLINE_FULL
606 bool "spectre_v2=on"
607
608endchoice
609
610config RELOCATABLE
611 bool "Build a relocatable kernel"
612 select MODULE_REL_CRCS if MODVERSIONS
613 default y
614 help
615 This builds a kernel image that retains relocation information
616 so it can be loaded at an arbitrary address.
617 The kernel is linked as a position-independent executable (PIE)
618 and contains dynamic relocations which are processed early in the
619 bootup process.
620 The relocations make the kernel image about 15% larger (compressed
621 10%), but are discarded at runtime.
622
623config RANDOMIZE_BASE
624 bool "Randomize the address of the kernel image (KASLR)"
625 depends on RELOCATABLE
626 default y
627 help
628 In support of Kernel Address Space Layout Randomization (KASLR),
629 this randomizes the address at which the kernel image is loaded,
630 as a security feature that deters exploit attempts relying on
631 knowledge of the location of kernel internals.
632
633endmenu
634
635menu "Memory setup"
636
637config ARCH_SPARSEMEM_ENABLE
638 def_bool y
639 select SPARSEMEM_VMEMMAP_ENABLE
640 select SPARSEMEM_VMEMMAP
641
642config ARCH_SPARSEMEM_DEFAULT
643 def_bool y
644
645config ARCH_ENABLE_MEMORY_HOTPLUG
646 def_bool y if SPARSEMEM
647
648config ARCH_ENABLE_MEMORY_HOTREMOVE
649 def_bool y
650
651config ARCH_ENABLE_SPLIT_PMD_PTLOCK
652 def_bool y
653
654config FORCE_MAX_ZONEORDER
655 int
656 default "9"
657
658config MAX_PHYSMEM_BITS
659 int "Maximum size of supported physical memory in bits (42-53)"
660 range 42 53
661 default "46"
662 help
663 This option specifies the maximum supported size of physical memory
664 in bits. Supported is any size between 2^42 (4TB) and 2^53 (8PB).
665 Increasing the number of bits also increases the kernel image size.
666 By default 46 bits (64TB) are supported.
667
668config PACK_STACK
669 def_bool y
670 prompt "Pack kernel stack"
671 help
672 This option enables the compiler option -mkernel-backchain if it
673 is available. If the option is available the compiler supports
674 the new stack layout which dramatically reduces the minimum stack
675 frame size. With an old compiler a non-leaf function needs a
676 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
677 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
678 and 24 byte on 64 bit.
679
680 Say Y if you are unsure.
681
682config CHECK_STACK
683 def_bool y
684 depends on !VMAP_STACK
685 prompt "Detect kernel stack overflow"
686 help
687 This option enables the compiler option -mstack-guard and
688 -mstack-size if they are available. If the compiler supports them
689 it will emit additional code to each function prolog to trigger
690 an illegal operation if the kernel stack is about to overflow.
691
692 Say N if you are unsure.
693
694config STACK_GUARD
695 int "Size of the guard area (128-1024)"
696 range 128 1024
697 depends on CHECK_STACK
698 default "256"
699 help
700 This allows you to specify the size of the guard area at the lower
701 end of the kernel stack. If the kernel stack points into the guard
702 area on function entry an illegal operation is triggered. The size
703 needs to be a power of 2. Please keep in mind that the size of an
704 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
705 The minimum size for the stack guard should be 256 for 31 bit and
706 512 for 64 bit.
707
708config WARN_DYNAMIC_STACK
709 def_bool n
710 prompt "Emit compiler warnings for function with dynamic stack usage"
711 help
712 This option enables the compiler option -mwarn-dynamicstack. If the
713 compiler supports this options generates warnings for functions
714 that dynamically allocate stack space using alloca.
715
716 Say N if you are unsure.
717
718endmenu
719
720menu "I/O subsystem"
721
722config QDIO
723 def_tristate y
724 prompt "QDIO support"
725 ---help---
726 This driver provides the Queued Direct I/O base support for
727 IBM System z.
728
729 To compile this driver as a module, choose M here: the
730 module will be called qdio.
731
732 If unsure, say Y.
733
734if PCI
735
736config PCI_NR_FUNCTIONS
737 int "Maximum number of PCI functions (1-4096)"
738 range 1 4096
739 default "128"
740 help
741 This allows you to specify the maximum number of PCI functions which
742 this kernel will support.
743
744endif
745
746config HAS_IOMEM
747 def_bool PCI
748
749config CHSC_SCH
750 def_tristate m
751 prompt "Support for CHSC subchannels"
752 help
753 This driver allows usage of CHSC subchannels. A CHSC subchannel
754 is usually present on LPAR only.
755 The driver creates a device /dev/chsc, which may be used to
756 obtain I/O configuration information about the machine and
757 to issue asynchronous chsc commands (DANGEROUS).
758 You will usually only want to use this interface on a special
759 LPAR designated for system management.
760
761 To compile this driver as a module, choose M here: the
762 module will be called chsc_sch.
763
764 If unsure, say N.
765
766config SCM_BUS
767 def_bool y
768 prompt "SCM bus driver"
769 help
770 Bus driver for Storage Class Memory.
771
772config EADM_SCH
773 def_tristate m
774 prompt "Support for EADM subchannels"
775 depends on SCM_BUS
776 help
777 This driver allows usage of EADM subchannels. EADM subchannels act
778 as a communication vehicle for SCM increments.
779
780 To compile this driver as a module, choose M here: the
781 module will be called eadm_sch.
782
783config VFIO_CCW
784 def_tristate n
785 prompt "Support for VFIO-CCW subchannels"
786 depends on S390_CCW_IOMMU && VFIO_MDEV
787 help
788 This driver allows usage of I/O subchannels via VFIO-CCW.
789
790 To compile this driver as a module, choose M here: the
791 module will be called vfio_ccw.
792
793config VFIO_AP
794 def_tristate n
795 prompt "VFIO support for AP devices"
796 depends on S390_AP_IOMMU && VFIO_MDEV_DEVICE && KVM
797 help
798 This driver grants access to Adjunct Processor (AP) devices
799 via the VFIO mediated device interface.
800
801 To compile this driver as a module, choose M here: the module
802 will be called vfio_ap.
803
804endmenu
805
806menu "Dump support"
807
808config CRASH_DUMP
809 bool "kernel crash dumps"
810 select KEXEC
811 help
812 Generate crash dump after being started by kexec.
813 Crash dump kernels are loaded in the main kernel with kexec-tools
814 into a specially reserved region and then later executed after
815 a crash by kdump/kexec.
816 Refer to <file:Documentation/s390/zfcpdump.rst> for more details on this.
817 This option also enables s390 zfcpdump.
818 See also <file:Documentation/s390/zfcpdump.rst>
819
820endmenu
821
822config SECCOMP
823 def_bool y
824 prompt "Enable seccomp to safely compute untrusted bytecode"
825 depends on PROC_FS
826 help
827 This kernel feature is useful for number crunching applications
828 that may need to compute untrusted bytecode during their
829 execution. By using pipes or other transports made available to
830 the process as file descriptors supporting the read/write
831 syscalls, it's possible to isolate those applications in
832 their own address space using seccomp. Once seccomp is
833 enabled via /proc/<pid>/seccomp, it cannot be disabled
834 and the task is only allowed to execute a few safe syscalls
835 defined by each seccomp mode.
836
837 If unsure, say Y.
838
839menu "Power Management"
840
841config ARCH_HIBERNATION_POSSIBLE
842 def_bool y
843
844source "kernel/power/Kconfig"
845
846endmenu
847
848config CCW
849 def_bool y
850
851config HAVE_PNETID
852 tristate
853 default (SMC || CCWGROUP)
854
855menu "Virtualization"
856
857config PROTECTED_VIRTUALIZATION_GUEST
858 def_bool n
859 prompt "Protected virtualization guest support"
860 help
861 Select this option, if you want to be able to run this
862 kernel as a protected virtualization KVM guest.
863 Protected virtualization capable machines have a mini hypervisor
864 located at machine level (an ultravisor). With help of the
865 Ultravisor, KVM will be able to run "protected" VMs, special
866 VMs whose memory and management data are unavailable to KVM.
867
868config PFAULT
869 def_bool y
870 prompt "Pseudo page fault support"
871 help
872 Select this option, if you want to use PFAULT pseudo page fault
873 handling under VM. If running native or in LPAR, this option
874 has no effect. If your VM does not support PFAULT, PAGEEX
875 pseudo page fault handling will be used.
876 Note that VM 4.2 supports PFAULT but has a bug in its
877 implementation that causes some problems.
878 Everybody who wants to run Linux under VM != VM4.2 should select
879 this option.
880
881config CMM
882 def_tristate n
883 prompt "Cooperative memory management"
884 help
885 Select this option, if you want to enable the kernel interface
886 to reduce the memory size of the system. This is accomplished
887 by allocating pages of memory and put them "on hold". This only
888 makes sense for a system running under VM where the unused pages
889 will be reused by VM for other guest systems. The interface
890 allows an external monitor to balance memory of many systems.
891 Everybody who wants to run Linux under VM should select this
892 option.
893
894config CMM_IUCV
895 def_bool y
896 prompt "IUCV special message interface to cooperative memory management"
897 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
898 help
899 Select this option to enable the special message interface to
900 the cooperative memory management.
901
902config APPLDATA_BASE
903 def_bool n
904 prompt "Linux - VM Monitor Stream, base infrastructure"
905 depends on PROC_FS
906 help
907 This provides a kernel interface for creating and updating z/VM APPLDATA
908 monitor records. The monitor records are updated at certain time
909 intervals, once the timer is started.
910 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
911 i.e. enables or disables monitoring on the Linux side.
912 A custom interval value (in seconds) can be written to
913 /proc/appldata/interval.
914
915 Defaults are 60 seconds interval and timer off.
916 The /proc entries can also be read from, showing the current settings.
917
918config APPLDATA_MEM
919 def_tristate m
920 prompt "Monitor memory management statistics"
921 depends on APPLDATA_BASE && VM_EVENT_COUNTERS
922 help
923 This provides memory management related data to the Linux - VM Monitor
924 Stream, like paging/swapping rate, memory utilisation, etc.
925 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
926 APPLDATA monitor record, i.e. enables or disables monitoring this record
927 on the z/VM side.
928
929 Default is disabled.
930 The /proc entry can also be read from, showing the current settings.
931
932 This can also be compiled as a module, which will be called
933 appldata_mem.o.
934
935config APPLDATA_OS
936 def_tristate m
937 prompt "Monitor OS statistics"
938 depends on APPLDATA_BASE
939 help
940 This provides OS related data to the Linux - VM Monitor Stream, like
941 CPU utilisation, etc.
942 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
943 APPLDATA monitor record, i.e. enables or disables monitoring this record
944 on the z/VM side.
945
946 Default is disabled.
947 This can also be compiled as a module, which will be called
948 appldata_os.o.
949
950config APPLDATA_NET_SUM
951 def_tristate m
952 prompt "Monitor overall network statistics"
953 depends on APPLDATA_BASE && NET
954 help
955 This provides network related data to the Linux - VM Monitor Stream,
956 currently there is only a total sum of network I/O statistics, no
957 per-interface data.
958 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
959 APPLDATA monitor record, i.e. enables or disables monitoring this record
960 on the z/VM side.
961
962 Default is disabled.
963 This can also be compiled as a module, which will be called
964 appldata_net_sum.o.
965
966config S390_HYPFS_FS
967 def_bool y
968 prompt "s390 hypervisor file system support"
969 select SYS_HYPERVISOR
970 help
971 This is a virtual file system intended to provide accounting
972 information in an s390 hypervisor environment.
973
974source "arch/s390/kvm/Kconfig"
975
976config S390_GUEST
977 def_bool y
978 prompt "s390 support for virtio devices"
979 select TTY
980 select VIRTUALIZATION
981 select VIRTIO
982 select VIRTIO_CONSOLE
983 help
984 Enabling this option adds support for virtio based paravirtual device
985 drivers on s390.
986
987 Select this option if you want to run the kernel as a guest under
988 the KVM hypervisor.
989
990endmenu
991
