1
2config MMU
3 def_bool y
4
5config CPU_BIG_ENDIAN
6 def_bool y
7
8config LOCKDEP_SUPPORT
9 def_bool y
10
11config STACKTRACE_SUPPORT
12 def_bool y
13
14config ARCH_HAS_ILOG2_U32
15 def_bool n
16
17config ARCH_HAS_ILOG2_U64
18 def_bool n
19
20config GENERIC_HWEIGHT
21 def_bool y
22
23config GENERIC_BUG
24 def_bool y if BUG
25
26config GENERIC_BUG_RELATIVE_POINTERS
27 def_bool y
28
29config GENERIC_LOCKBREAK
30 def_bool y if PREEMPTION
31
32config PGSTE
33 def_bool y if KVM
34
35config AUDIT_ARCH
36 def_bool y
37
38config NO_IOPORT_MAP
39 def_bool y
40
41config PCI_QUIRKS
42 def_bool n
43
44config ARCH_SUPPORTS_UPROBES
45 def_bool y
46
47config KASAN_SHADOW_OFFSET
48 hex
49 depends on KASAN
50 default 0x18000000000000
51
52config S390
53 def_bool y
54
55
56
57 imply IMA_SECURE_AND_OR_TRUSTED_BOOT
58 select ARCH_32BIT_USTAT_F_TINODE
59 select ARCH_BINFMT_ELF_STATE
60 select ARCH_ENABLE_MEMORY_HOTPLUG if SPARSEMEM
61 select ARCH_ENABLE_MEMORY_HOTREMOVE
62 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
63 select ARCH_HAS_DEBUG_VM_PGTABLE
64 select ARCH_HAS_DEBUG_WX
65 select ARCH_HAS_DEVMEM_IS_ALLOWED
66 select ARCH_HAS_ELF_RANDOMIZE
67 select ARCH_HAS_FORCE_DMA_UNENCRYPTED
68 select ARCH_HAS_FORTIFY_SOURCE
69 select ARCH_HAS_GCOV_PROFILE_ALL
70 select ARCH_HAS_GIGANTIC_PAGE
71 select ARCH_HAS_KCOV
72 select ARCH_HAS_MEM_ENCRYPT
73 select ARCH_HAS_PTE_SPECIAL
74 select ARCH_HAS_SCALED_CPUTIME
75 select ARCH_HAS_SET_MEMORY
76 select ARCH_HAS_STRICT_KERNEL_RWX
77 select ARCH_HAS_STRICT_MODULE_RWX
78 select ARCH_HAS_SYSCALL_WRAPPER
79 select ARCH_HAS_UBSAN_SANITIZE_ALL
80 select ARCH_HAS_VDSO_DATA
81 select ARCH_HAVE_NMI_SAFE_CMPXCHG
82 select ARCH_INLINE_READ_LOCK
83 select ARCH_INLINE_READ_LOCK_BH
84 select ARCH_INLINE_READ_LOCK_IRQ
85 select ARCH_INLINE_READ_LOCK_IRQSAVE
86 select ARCH_INLINE_READ_TRYLOCK
87 select ARCH_INLINE_READ_UNLOCK
88 select ARCH_INLINE_READ_UNLOCK_BH
89 select ARCH_INLINE_READ_UNLOCK_IRQ
90 select ARCH_INLINE_READ_UNLOCK_IRQRESTORE
91 select ARCH_INLINE_SPIN_LOCK
92 select ARCH_INLINE_SPIN_LOCK_BH
93 select ARCH_INLINE_SPIN_LOCK_IRQ
94 select ARCH_INLINE_SPIN_LOCK_IRQSAVE
95 select ARCH_INLINE_SPIN_TRYLOCK
96 select ARCH_INLINE_SPIN_TRYLOCK_BH
97 select ARCH_INLINE_SPIN_UNLOCK
98 select ARCH_INLINE_SPIN_UNLOCK_BH
99 select ARCH_INLINE_SPIN_UNLOCK_IRQ
100 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE
101 select ARCH_INLINE_WRITE_LOCK
102 select ARCH_INLINE_WRITE_LOCK_BH
103 select ARCH_INLINE_WRITE_LOCK_IRQ
104 select ARCH_INLINE_WRITE_LOCK_IRQSAVE
105 select ARCH_INLINE_WRITE_TRYLOCK
106 select ARCH_INLINE_WRITE_UNLOCK
107 select ARCH_INLINE_WRITE_UNLOCK_BH
108 select ARCH_INLINE_WRITE_UNLOCK_IRQ
109 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
110 select ARCH_STACKWALK
111 select ARCH_SUPPORTS_ATOMIC_RMW
112 select ARCH_SUPPORTS_DEBUG_PAGEALLOC
113 select ARCH_SUPPORTS_HUGETLBFS
114 select ARCH_SUPPORTS_NUMA_BALANCING
115 select ARCH_USE_BUILTIN_BSWAP
116 select ARCH_USE_CMPXCHG_LOCKREF
117 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
118 select ARCH_WANTS_NO_INSTR
119 select ARCH_WANT_DEFAULT_BPF_JIT
120 select ARCH_WANT_IPC_PARSE_VERSION
121 select BUILDTIME_TABLE_SORT
122 select CLONE_BACKWARDS2
123 select CPU_NO_EFFICIENT_FFS if !HAVE_MARCH_Z9_109_FEATURES
124 select DMA_OPS if PCI
125 select DYNAMIC_FTRACE if FUNCTION_TRACER
126 select GENERIC_ALLOCATOR
127 select GENERIC_CPU_AUTOPROBE
128 select GENERIC_CPU_VULNERABILITIES
129 select GENERIC_ENTRY
130 select GENERIC_FIND_FIRST_BIT
131 select GENERIC_GETTIMEOFDAY
132 select GENERIC_PTDUMP
133 select GENERIC_SMP_IDLE_THREAD
134 select GENERIC_TIME_VSYSCALL
135 select GENERIC_VDSO_TIME_NS
136 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
137 select HAVE_ARCH_AUDITSYSCALL
138 select HAVE_ARCH_JUMP_LABEL
139 select HAVE_ARCH_JUMP_LABEL_RELATIVE
140 select HAVE_ARCH_KASAN
141 select HAVE_ARCH_KASAN_VMALLOC
142 select HAVE_ARCH_KCSAN
143 select HAVE_ARCH_KFENCE
144 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
145 select HAVE_ARCH_SECCOMP_FILTER
146 select HAVE_ARCH_SOFT_DIRTY
147 select HAVE_ARCH_TRACEHOOK
148 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
149 select HAVE_ARCH_VMAP_STACK
150 select HAVE_ASM_MODVERSIONS
151 select HAVE_CMPXCHG_DOUBLE
152 select HAVE_CMPXCHG_LOCAL
153 select HAVE_DEBUG_KMEMLEAK
154 select HAVE_DMA_CONTIGUOUS
155 select HAVE_DYNAMIC_FTRACE
156 select HAVE_DYNAMIC_FTRACE_WITH_REGS
157 select HAVE_EBPF_JIT if PACK_STACK && HAVE_MARCH_Z196_FEATURES
158 select HAVE_EFFICIENT_UNALIGNED_ACCESS
159 select HAVE_FAST_GUP
160 select HAVE_FENTRY
161 select HAVE_FTRACE_MCOUNT_RECORD
162 select HAVE_FUNCTION_ERROR_INJECTION
163 select HAVE_FUNCTION_GRAPH_TRACER
164 select HAVE_FUNCTION_TRACER
165 select HAVE_FUTEX_CMPXCHG if FUTEX
166 select HAVE_GCC_PLUGINS
167 select HAVE_GENERIC_VDSO
168 select HAVE_IOREMAP_PROT if PCI
169 select HAVE_KERNEL_BZIP2
170 select HAVE_KERNEL_GZIP
171 select HAVE_KERNEL_LZ4
172 select HAVE_KERNEL_LZMA
173 select HAVE_KERNEL_LZO
174 select HAVE_KERNEL_UNCOMPRESSED
175 select HAVE_KERNEL_XZ
176 select HAVE_KERNEL_ZSTD
177 select HAVE_KPROBES
178 select HAVE_KPROBES_ON_FTRACE
179 select HAVE_KRETPROBES
180 select HAVE_KVM
181 select HAVE_LIVEPATCH
182 select HAVE_MEMBLOCK_PHYS_MAP
183 select HAVE_MOD_ARCH_SPECIFIC
184 select HAVE_NMI
185 select HAVE_NOP_MCOUNT
186 select HAVE_PCI
187 select HAVE_PERF_EVENTS
188 select HAVE_PERF_REGS
189 select HAVE_PERF_USER_STACK_DUMP
190 select HAVE_REGS_AND_STACK_ACCESS_API
191 select HAVE_RELIABLE_STACKTRACE
192 select HAVE_RSEQ
193 select HAVE_SOFTIRQ_ON_OWN_STACK
194 select HAVE_SYSCALL_TRACEPOINTS
195 select HAVE_VIRT_CPU_ACCOUNTING
196 select HAVE_VIRT_CPU_ACCOUNTING_IDLE
197 select IOMMU_HELPER if PCI
198 select IOMMU_SUPPORT if PCI
199 select MMU_GATHER_NO_GATHER
200 select MMU_GATHER_RCU_TABLE_FREE
201 select MODULES_USE_ELF_RELA
202 select NEED_DMA_MAP_STATE if PCI
203 select NEED_SG_DMA_LENGTH if PCI
204 select OLD_SIGACTION
205 select OLD_SIGSUSPEND3
206 select PCI_DOMAINS if PCI
207 select PCI_MSI if PCI
208 select PCI_MSI_ARCH_FALLBACKS if PCI_MSI
209 select SPARSE_IRQ
210 select SWIOTLB
211 select SYSCTL_EXCEPTION_TRACE
212 select THREAD_INFO_IN_TASK
213 select TRACE_IRQFLAGS_SUPPORT
214 select TTY
215 select VIRT_CPU_ACCOUNTING
216 select ZONE_DMA
217
218
219config SCHED_OMIT_FRAME_POINTER
220 def_bool y
221
222config PGTABLE_LEVELS
223 int
224 default 5
225
226source "kernel/livepatch/Kconfig"
227
228menu "Processor type and features"
229
230config HAVE_MARCH_Z900_FEATURES
231 def_bool n
232
233config HAVE_MARCH_Z990_FEATURES
234 def_bool n
235 select HAVE_MARCH_Z900_FEATURES
236
237config HAVE_MARCH_Z9_109_FEATURES
238 def_bool n
239 select HAVE_MARCH_Z990_FEATURES
240
241config HAVE_MARCH_Z10_FEATURES
242 def_bool n
243 select HAVE_MARCH_Z9_109_FEATURES
244
245config HAVE_MARCH_Z196_FEATURES
246 def_bool n
247 select HAVE_MARCH_Z10_FEATURES
248
249config HAVE_MARCH_ZEC12_FEATURES
250 def_bool n
251 select HAVE_MARCH_Z196_FEATURES
252
253config HAVE_MARCH_Z13_FEATURES
254 def_bool n
255 select HAVE_MARCH_ZEC12_FEATURES
256
257config HAVE_MARCH_Z14_FEATURES
258 def_bool n
259 select HAVE_MARCH_Z13_FEATURES
260
261config HAVE_MARCH_Z15_FEATURES
262 def_bool n
263 select HAVE_MARCH_Z14_FEATURES
264
265choice
266 prompt "Processor type"
267 default MARCH_Z196
268
269config MARCH_Z900
270 bool "IBM zSeries model z800 and z900"
271 select HAVE_MARCH_Z900_FEATURES
272 depends on $(cc-option,-march=z900)
273 help
274 Select this to enable optimizations for model z800/z900 (2064 and
275 2066 series). This will enable some optimizations that are not
276 available on older ESA/390 (31 Bit) only CPUs.
277
278config MARCH_Z990
279 bool "IBM zSeries model z890 and z990"
280 select HAVE_MARCH_Z990_FEATURES
281 depends on $(cc-option,-march=z990)
282 help
283 Select this to enable optimizations for model z890/z990 (2084 and
284 2086 series). The kernel will be slightly faster but will not work
285 on older machines.
286
287config MARCH_Z9_109
288 bool "IBM System z9"
289 select HAVE_MARCH_Z9_109_FEATURES
290 depends on $(cc-option,-march=z9-109)
291 help
292 Select this to enable optimizations for IBM System z9 (2094 and
293 2096 series). The kernel will be slightly faster but will not work
294 on older machines.
295
296config MARCH_Z10
297 bool "IBM System z10"
298 select HAVE_MARCH_Z10_FEATURES
299 depends on $(cc-option,-march=z10)
300 help
301 Select this to enable optimizations for IBM System z10 (2097 and
302 2098 series). The kernel will be slightly faster but will not work
303 on older machines.
304
305config MARCH_Z196
306 bool "IBM zEnterprise 114 and 196"
307 select HAVE_MARCH_Z196_FEATURES
308 depends on $(cc-option,-march=z196)
309 help
310 Select this to enable optimizations for IBM zEnterprise 114 and 196
311 (2818 and 2817 series). The kernel will be slightly faster but will
312 not work on older machines.
313
314config MARCH_ZEC12
315 bool "IBM zBC12 and zEC12"
316 select HAVE_MARCH_ZEC12_FEATURES
317 depends on $(cc-option,-march=zEC12)
318 help
319 Select this to enable optimizations for IBM zBC12 and zEC12 (2828 and
320 2827 series). The kernel will be slightly faster but will not work on
321 older machines.
322
323config MARCH_Z13
324 bool "IBM z13s and z13"
325 select HAVE_MARCH_Z13_FEATURES
326 depends on $(cc-option,-march=z13)
327 help
328 Select this to enable optimizations for IBM z13s and z13 (2965 and
329 2964 series). The kernel will be slightly faster but will not work on
330 older machines.
331
332config MARCH_Z14
333 bool "IBM z14 ZR1 and z14"
334 select HAVE_MARCH_Z14_FEATURES
335 depends on $(cc-option,-march=z14)
336 help
337 Select this to enable optimizations for IBM z14 ZR1 and z14 (3907
338 and 3906 series). The kernel will be slightly faster but will not
339 work on older machines.
340
341config MARCH_Z15
342 bool "IBM z15"
343 select HAVE_MARCH_Z15_FEATURES
344 depends on $(cc-option,-march=z15)
345 help
346 Select this to enable optimizations for IBM z15 (8562
347 and 8561 series). The kernel will be slightly faster but will not
348 work on older machines.
349
350endchoice
351
352config MARCH_Z900_TUNE
353 def_bool TUNE_Z900 || MARCH_Z900 && TUNE_DEFAULT
354
355config MARCH_Z990_TUNE
356 def_bool TUNE_Z990 || MARCH_Z990 && TUNE_DEFAULT
357
358config MARCH_Z9_109_TUNE
359 def_bool TUNE_Z9_109 || MARCH_Z9_109 && TUNE_DEFAULT
360
361config MARCH_Z10_TUNE
362 def_bool TUNE_Z10 || MARCH_Z10 && TUNE_DEFAULT
363
364config MARCH_Z196_TUNE
365 def_bool TUNE_Z196 || MARCH_Z196 && TUNE_DEFAULT
366
367config MARCH_ZEC12_TUNE
368 def_bool TUNE_ZEC12 || MARCH_ZEC12 && TUNE_DEFAULT
369
370config MARCH_Z13_TUNE
371 def_bool TUNE_Z13 || MARCH_Z13 && TUNE_DEFAULT
372
373config MARCH_Z14_TUNE
374 def_bool TUNE_Z14 || MARCH_Z14 && TUNE_DEFAULT
375
376config MARCH_Z15_TUNE
377 def_bool TUNE_Z15 || MARCH_Z15 && TUNE_DEFAULT
378
379choice
380 prompt "Tune code generation"
381 default TUNE_DEFAULT
382 help
383 Cause the compiler to tune (-mtune) the generated code for a machine.
384 This will make the code run faster on the selected machine but
385 somewhat slower on other machines.
386 This option only changes how the compiler emits instructions, not the
387 selection of instructions itself, so the resulting kernel will run on
388 all other machines.
389
390config TUNE_DEFAULT
391 bool "Default"
392 help
393 Tune the generated code for the target processor for which the kernel
394 will be compiled.
395
396config TUNE_Z900
397 bool "IBM zSeries model z800 and z900"
398 depends on $(cc-option,-mtune=z900)
399
400config TUNE_Z990
401 bool "IBM zSeries model z890 and z990"
402 depends on $(cc-option,-mtune=z990)
403
404config TUNE_Z9_109
405 bool "IBM System z9"
406 depends on $(cc-option,-mtune=z9-109)
407
408config TUNE_Z10
409 bool "IBM System z10"
410 depends on $(cc-option,-mtune=z10)
411
412config TUNE_Z196
413 bool "IBM zEnterprise 114 and 196"
414 depends on $(cc-option,-mtune=z196)
415
416config TUNE_ZEC12
417 bool "IBM zBC12 and zEC12"
418 depends on $(cc-option,-mtune=zEC12)
419
420config TUNE_Z13
421 bool "IBM z13s and z13"
422 depends on $(cc-option,-mtune=z13)
423
424config TUNE_Z14
425 bool "IBM z14 ZR1 and z14"
426 depends on $(cc-option,-mtune=z14)
427
428config TUNE_Z15
429 bool "IBM z15"
430 depends on $(cc-option,-mtune=z15)
431
432endchoice
433
434config 64BIT
435 def_bool y
436
437config COMPAT
438 def_bool y
439 prompt "Kernel support for 31 bit emulation"
440 select ARCH_WANT_OLD_COMPAT_IPC
441 select COMPAT_OLD_SIGACTION
442 select HAVE_UID16
443 depends on MULTIUSER
444 depends on !CC_IS_CLANG
445 help
446 Select this option if you want to enable your system kernel to
447 handle system-calls from ELF binaries for 31 bit ESA. This option
448 (and some other stuff like libraries and such) is needed for
449 executing 31 bit applications. It is safe to say "Y".
450
451config SYSVIPC_COMPAT
452 def_bool y if COMPAT && SYSVIPC
453
454config SMP
455 def_bool y
456
457config NR_CPUS
458 int "Maximum number of CPUs (2-512)"
459 range 2 512
460 default "64"
461 help
462 This allows you to specify the maximum number of CPUs which this
463 kernel will support. The maximum supported value is 512 and the
464 minimum value which makes sense is 2.
465
466 This is purely to save memory - each supported CPU adds
467 approximately sixteen kilobytes to the kernel image.
468
469config HOTPLUG_CPU
470 def_bool y
471
472config NUMA
473 bool "NUMA support"
474 depends on SCHED_TOPOLOGY
475 default n
476 help
477 Enable NUMA support
478
479 This option adds NUMA support to the kernel.
480
481config NODES_SHIFT
482 int
483 depends on NUMA
484 default "1"
485
486config SCHED_SMT
487 def_bool n
488
489config SCHED_MC
490 def_bool n
491
492config SCHED_BOOK
493 def_bool n
494
495config SCHED_DRAWER
496 def_bool n
497
498config SCHED_TOPOLOGY
499 def_bool y
500 prompt "Topology scheduler support"
501 select SCHED_SMT
502 select SCHED_MC
503 select SCHED_BOOK
504 select SCHED_DRAWER
505 help
506 Topology scheduler support improves the CPU scheduler's decision
507 making when dealing with machines that have multi-threading,
508 multiple cores or multiple books.
509
510source "kernel/Kconfig.hz"
511
512config KEXEC
513 def_bool y
514 select KEXEC_CORE
515
516config KEXEC_FILE
517 bool "kexec file based system call"
518 select KEXEC_CORE
519 select BUILD_BIN2C
520 depends on CRYPTO
521 depends on CRYPTO_SHA256
522 depends on CRYPTO_SHA256_S390
523 help
524 Enable the kexec file based system call. In contrast to the normal
525 kexec system call this system call takes file descriptors for the
526 kernel and initramfs as arguments.
527
528config ARCH_HAS_KEXEC_PURGATORY
529 def_bool y
530 depends on KEXEC_FILE
531
532config KEXEC_SIG
533 bool "Verify kernel signature during kexec_file_load() syscall"
534 depends on KEXEC_FILE && MODULE_SIG_FORMAT
535 help
536 This option makes kernel signature verification mandatory for
537 the kexec_file_load() syscall.
538
539 In addition to that option, you need to enable signature
540 verification for the corresponding kernel image type being
541 loaded in order for this to work.
542
543config ARCH_RANDOM
544 def_bool y
545 prompt "s390 architectural random number generation API"
546 help
547 Enable the s390 architectural random number generation API
548 to provide random data for all consumers within the Linux
549 kernel.
550
551 When enabled the arch_random_* functions declared in linux/random.h
552 are implemented. The implementation is based on the s390 CPACF
553 instruction subfunction TRNG which provides a real true random
554 number generator.
555
556 If unsure, say Y.
557
558config KERNEL_NOBP
559 def_bool n
560 prompt "Enable modified branch prediction for the kernel by default"
561 help
562 If this option is selected the kernel will switch to a modified
563 branch prediction mode if the firmware interface is available.
564 The modified branch prediction mode improves the behaviour in
565 regard to speculative execution.
566
567 With the option enabled the kernel parameter "nobp=0" or "nospec"
568 can be used to run the kernel in the normal branch prediction mode.
569
570 With the option disabled the modified branch prediction mode is
571 enabled with the "nobp=1" kernel parameter.
572
573 If unsure, say N.
574
575config EXPOLINE
576 def_bool n
577 prompt "Avoid speculative indirect branches in the kernel"
578 help
579 Compile the kernel with the expoline compiler options to guard
580 against kernel-to-user data leaks by avoiding speculative indirect
581 branches.
582 Requires a compiler with -mindirect-branch=thunk support for full
583 protection. The kernel may run slower.
584
585 If unsure, say N.
586
587choice
588 prompt "Expoline default"
589 depends on EXPOLINE
590 default EXPOLINE_FULL
591
592config EXPOLINE_OFF
593 bool "spectre_v2=off"
594
595config EXPOLINE_AUTO
596 bool "spectre_v2=auto"
597
598config EXPOLINE_FULL
599 bool "spectre_v2=on"
600
601endchoice
602
603config RELOCATABLE
604 bool "Build a relocatable kernel"
605 select MODULE_REL_CRCS if MODVERSIONS
606 default y
607 help
608 This builds a kernel image that retains relocation information
609 so it can be loaded at an arbitrary address.
610 The kernel is linked as a position-independent executable (PIE)
611 and contains dynamic relocations which are processed early in the
612 bootup process.
613 The relocations make the kernel image about 15% larger (compressed
614 10%), but are discarded at runtime.
615
616config RANDOMIZE_BASE
617 bool "Randomize the address of the kernel image (KASLR)"
618 depends on RELOCATABLE
619 default y
620 help
621 In support of Kernel Address Space Layout Randomization (KASLR),
622 this randomizes the address at which the kernel image is loaded,
623 as a security feature that deters exploit attempts relying on
624 knowledge of the location of kernel internals.
625
626endmenu
627
628menu "Memory setup"
629
630config ARCH_SPARSEMEM_ENABLE
631 def_bool y
632 select SPARSEMEM_VMEMMAP_ENABLE
633 select SPARSEMEM_VMEMMAP
634
635config ARCH_SPARSEMEM_DEFAULT
636 def_bool y
637
638config MAX_PHYSMEM_BITS
639 int "Maximum size of supported physical memory in bits (42-53)"
640 range 42 53
641 default "46"
642 help
643 This option specifies the maximum supported size of physical memory
644 in bits. Supported is any size between 2^42 (4TB) and 2^53 (8PB).
645 Increasing the number of bits also increases the kernel image size.
646 By default 46 bits (64TB) are supported.
647
648config PACK_STACK
649 def_bool y
650 prompt "Pack kernel stack"
651 help
652 This option enables the compiler option -mkernel-backchain if it
653 is available. If the option is available the compiler supports
654 the new stack layout which dramatically reduces the minimum stack
655 frame size. With an old compiler a non-leaf function needs a
656 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
657 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
658 and 24 byte on 64 bit.
659
660 Say Y if you are unsure.
661
662config CHECK_STACK
663 def_bool y
664 depends on !VMAP_STACK
665 prompt "Detect kernel stack overflow"
666 help
667 This option enables the compiler option -mstack-guard and
668 -mstack-size if they are available. If the compiler supports them
669 it will emit additional code to each function prolog to trigger
670 an illegal operation if the kernel stack is about to overflow.
671
672 Say N if you are unsure.
673
674config STACK_GUARD
675 int "Size of the guard area (128-1024)"
676 range 128 1024
677 depends on CHECK_STACK
678 default "256"
679 help
680 This allows you to specify the size of the guard area at the lower
681 end of the kernel stack. If the kernel stack points into the guard
682 area on function entry an illegal operation is triggered. The size
683 needs to be a power of 2. Please keep in mind that the size of an
684 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
685 The minimum size for the stack guard should be 256 for 31 bit and
686 512 for 64 bit.
687
688endmenu
689
690menu "I/O subsystem"
691
692config QDIO
693 def_tristate y
694 prompt "QDIO support"
695 help
696 This driver provides the Queued Direct I/O base support for
697 IBM System z.
698
699 To compile this driver as a module, choose M here: the
700 module will be called qdio.
701
702 If unsure, say Y.
703
704if PCI
705
706config PCI_NR_FUNCTIONS
707 int "Maximum number of PCI functions (1-4096)"
708 range 1 4096
709 default "512"
710 help
711 This allows you to specify the maximum number of PCI functions which
712 this kernel will support.
713
714endif
715
716config HAS_IOMEM
717 def_bool PCI
718
719config CHSC_SCH
720 def_tristate m
721 prompt "Support for CHSC subchannels"
722 help
723 This driver allows usage of CHSC subchannels. A CHSC subchannel
724 is usually present on LPAR only.
725 The driver creates a device /dev/chsc, which may be used to
726 obtain I/O configuration information about the machine and
727 to issue asynchronous chsc commands (DANGEROUS).
728 You will usually only want to use this interface on a special
729 LPAR designated for system management.
730
731 To compile this driver as a module, choose M here: the
732 module will be called chsc_sch.
733
734 If unsure, say N.
735
736config SCM_BUS
737 def_bool y
738 prompt "SCM bus driver"
739 help
740 Bus driver for Storage Class Memory.
741
742config EADM_SCH
743 def_tristate m
744 prompt "Support for EADM subchannels"
745 depends on SCM_BUS
746 help
747 This driver allows usage of EADM subchannels. EADM subchannels act
748 as a communication vehicle for SCM increments.
749
750 To compile this driver as a module, choose M here: the
751 module will be called eadm_sch.
752
753config VFIO_CCW
754 def_tristate n
755 prompt "Support for VFIO-CCW subchannels"
756 depends on S390_CCW_IOMMU && VFIO_MDEV
757 help
758 This driver allows usage of I/O subchannels via VFIO-CCW.
759
760 To compile this driver as a module, choose M here: the
761 module will be called vfio_ccw.
762
763config VFIO_AP
764 def_tristate n
765 prompt "VFIO support for AP devices"
766 depends on S390_AP_IOMMU && VFIO_MDEV && KVM
767 depends on ZCRYPT
768 help
769 This driver grants access to Adjunct Processor (AP) devices
770 via the VFIO mediated device interface.
771
772 To compile this driver as a module, choose M here: the module
773 will be called vfio_ap.
774
775endmenu
776
777menu "Dump support"
778
779config CRASH_DUMP
780 bool "kernel crash dumps"
781 select KEXEC
782 help
783 Generate crash dump after being started by kexec.
784 Crash dump kernels are loaded in the main kernel with kexec-tools
785 into a specially reserved region and then later executed after
786 a crash by kdump/kexec.
787 Refer to <file:Documentation/s390/zfcpdump.rst> for more details on this.
788 This option also enables s390 zfcpdump.
789 See also <file:Documentation/s390/zfcpdump.rst>
790
791endmenu
792
793config CCW
794 def_bool y
795
796config HAVE_PNETID
797 tristate
798 default (SMC || CCWGROUP)
799
800menu "Virtualization"
801
802config PROTECTED_VIRTUALIZATION_GUEST
803 def_bool n
804 prompt "Protected virtualization guest support"
805 select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
806 help
807 Select this option, if you want to be able to run this
808 kernel as a protected virtualization KVM guest.
809 Protected virtualization capable machines have a mini hypervisor
810 located at machine level (an ultravisor). With help of the
811 Ultravisor, KVM will be able to run "protected" VMs, special
812 VMs whose memory and management data are unavailable to KVM.
813
814config PFAULT
815 def_bool y
816 prompt "Pseudo page fault support"
817 help
818 Select this option, if you want to use PFAULT pseudo page fault
819 handling under VM. If running native or in LPAR, this option
820 has no effect. If your VM does not support PFAULT, PAGEEX
821 pseudo page fault handling will be used.
822 Note that VM 4.2 supports PFAULT but has a bug in its
823 implementation that causes some problems.
824 Everybody who wants to run Linux under VM != VM4.2 should select
825 this option.
826
827config CMM
828 def_tristate n
829 prompt "Cooperative memory management"
830 help
831 Select this option, if you want to enable the kernel interface
832 to reduce the memory size of the system. This is accomplished
833 by allocating pages of memory and put them "on hold". This only
834 makes sense for a system running under VM where the unused pages
835 will be reused by VM for other guest systems. The interface
836 allows an external monitor to balance memory of many systems.
837 Everybody who wants to run Linux under VM should select this
838 option.
839
840config CMM_IUCV
841 def_bool y
842 prompt "IUCV special message interface to cooperative memory management"
843 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
844 help
845 Select this option to enable the special message interface to
846 the cooperative memory management.
847
848config APPLDATA_BASE
849 def_bool n
850 prompt "Linux - VM Monitor Stream, base infrastructure"
851 depends on PROC_SYSCTL
852 help
853 This provides a kernel interface for creating and updating z/VM APPLDATA
854 monitor records. The monitor records are updated at certain time
855 intervals, once the timer is started.
856 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
857 i.e. enables or disables monitoring on the Linux side.
858 A custom interval value (in seconds) can be written to
859 /proc/appldata/interval.
860
861 Defaults are 60 seconds interval and timer off.
862 The /proc entries can also be read from, showing the current settings.
863
864config APPLDATA_MEM
865 def_tristate m
866 prompt "Monitor memory management statistics"
867 depends on APPLDATA_BASE && VM_EVENT_COUNTERS
868 help
869 This provides memory management related data to the Linux - VM Monitor
870 Stream, like paging/swapping rate, memory utilisation, etc.
871 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
872 APPLDATA monitor record, i.e. enables or disables monitoring this record
873 on the z/VM side.
874
875 Default is disabled.
876 The /proc entry can also be read from, showing the current settings.
877
878 This can also be compiled as a module, which will be called
879 appldata_mem.o.
880
881config APPLDATA_OS
882 def_tristate m
883 prompt "Monitor OS statistics"
884 depends on APPLDATA_BASE
885 help
886 This provides OS related data to the Linux - VM Monitor Stream, like
887 CPU utilisation, etc.
888 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
889 APPLDATA monitor record, i.e. enables or disables monitoring this record
890 on the z/VM side.
891
892 Default is disabled.
893 This can also be compiled as a module, which will be called
894 appldata_os.o.
895
896config APPLDATA_NET_SUM
897 def_tristate m
898 prompt "Monitor overall network statistics"
899 depends on APPLDATA_BASE && NET
900 help
901 This provides network related data to the Linux - VM Monitor Stream,
902 currently there is only a total sum of network I/O statistics, no
903 per-interface data.
904 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
905 APPLDATA monitor record, i.e. enables or disables monitoring this record
906 on the z/VM side.
907
908 Default is disabled.
909 This can also be compiled as a module, which will be called
910 appldata_net_sum.o.
911
912config S390_HYPFS_FS
913 def_bool y
914 prompt "s390 hypervisor file system support"
915 select SYS_HYPERVISOR
916 help
917 This is a virtual file system intended to provide accounting
918 information in an s390 hypervisor environment.
919
920source "arch/s390/kvm/Kconfig"
921
922config S390_GUEST
923 def_bool y
924 prompt "s390 support for virtio devices"
925 select TTY
926 select VIRTUALIZATION
927 select VIRTIO
928 help
929 Enabling this option adds support for virtio based paravirtual device
930 drivers on s390.
931
932 Select this option if you want to run the kernel as a guest under
933 the KVM hypervisor.
934
935endmenu
936
937menu "Selftests"
938
939config S390_UNWIND_SELFTEST
940 def_tristate n
941 prompt "Test unwind functions"
942 help
943 This option enables s390 specific stack unwinder testing kernel
944 module. This option is not useful for distributions or general
945 kernels, but only for kernel developers working on architecture code.
946
947 Say N if you are unsure.
948
949endmenu
950
