xref: /openbmc/linux/arch/s390/Kconfig (revision 7b73a9c8)
1# SPDX-License-Identifier: GPL-2.0
2config MMU
3	def_bool y
4
5config ZONE_DMA
6	def_bool y
7
8config CPU_BIG_ENDIAN
9	def_bool y
10
11config LOCKDEP_SUPPORT
12	def_bool y
13
14config STACKTRACE_SUPPORT
15	def_bool y
16
17config ARCH_HAS_ILOG2_U32
18	def_bool n
19
20config ARCH_HAS_ILOG2_U64
21	def_bool n
22
23config GENERIC_HWEIGHT
24	def_bool y
25
26config GENERIC_BUG
27	def_bool y if BUG
28
29config GENERIC_BUG_RELATIVE_POINTERS
30	def_bool y
31
32config GENERIC_LOCKBREAK
33	def_bool y if PREEMPT
34
35config PGSTE
36	def_bool y if KVM
37
38config ARCH_SUPPORTS_DEBUG_PAGEALLOC
39	def_bool y
40
41config AUDIT_ARCH
42	def_bool y
43
44config NO_IOPORT_MAP
45	def_bool y
46
47config PCI_QUIRKS
48	def_bool n
49
50config ARCH_SUPPORTS_UPROBES
51	def_bool y
52
53config KASAN_SHADOW_OFFSET
54	hex
55	depends on KASAN
56	default 0x18000000000000 if KASAN_S390_4_LEVEL_PAGING
57	default 0x30000000000
58
59config S390
60	def_bool y
61	select ARCH_BINFMT_ELF_STATE
62	select ARCH_HAS_DEVMEM_IS_ALLOWED
63	select ARCH_HAS_ELF_RANDOMIZE
64	select ARCH_HAS_FORTIFY_SOURCE
65	select ARCH_HAS_GCOV_PROFILE_ALL
66	select ARCH_HAS_GIGANTIC_PAGE
67	select ARCH_HAS_KCOV
68	select ARCH_HAS_MEM_ENCRYPT
69	select ARCH_HAS_PTE_SPECIAL
70	select ARCH_HAS_SET_MEMORY
71	select ARCH_HAS_STRICT_KERNEL_RWX
72	select ARCH_HAS_STRICT_MODULE_RWX
73	select ARCH_HAS_SYSCALL_WRAPPER
74	select ARCH_HAS_UBSAN_SANITIZE_ALL
75	select ARCH_HAVE_NMI_SAFE_CMPXCHG
76	select ARCH_INLINE_READ_LOCK
77	select ARCH_INLINE_READ_LOCK_BH
78	select ARCH_INLINE_READ_LOCK_IRQ
79	select ARCH_INLINE_READ_LOCK_IRQSAVE
80	select ARCH_INLINE_READ_TRYLOCK
81	select ARCH_INLINE_READ_UNLOCK
82	select ARCH_INLINE_READ_UNLOCK_BH
83	select ARCH_INLINE_READ_UNLOCK_IRQ
84	select ARCH_INLINE_READ_UNLOCK_IRQRESTORE
85	select ARCH_INLINE_SPIN_LOCK
86	select ARCH_INLINE_SPIN_LOCK_BH
87	select ARCH_INLINE_SPIN_LOCK_IRQ
88	select ARCH_INLINE_SPIN_LOCK_IRQSAVE
89	select ARCH_INLINE_SPIN_TRYLOCK
90	select ARCH_INLINE_SPIN_TRYLOCK_BH
91	select ARCH_INLINE_SPIN_UNLOCK
92	select ARCH_INLINE_SPIN_UNLOCK_BH
93	select ARCH_INLINE_SPIN_UNLOCK_IRQ
94	select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE
95	select ARCH_INLINE_WRITE_LOCK
96	select ARCH_INLINE_WRITE_LOCK_BH
97	select ARCH_INLINE_WRITE_LOCK_IRQ
98	select ARCH_INLINE_WRITE_LOCK_IRQSAVE
99	select ARCH_INLINE_WRITE_TRYLOCK
100	select ARCH_INLINE_WRITE_UNLOCK
101	select ARCH_INLINE_WRITE_UNLOCK_BH
102	select ARCH_INLINE_WRITE_UNLOCK_IRQ
103	select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
104	select ARCH_KEEP_MEMBLOCK
105	select ARCH_SAVE_PAGE_KEYS if HIBERNATION
106	select ARCH_STACKWALK
107	select ARCH_SUPPORTS_ATOMIC_RMW
108	select ARCH_SUPPORTS_NUMA_BALANCING
109	select ARCH_USE_BUILTIN_BSWAP
110	select ARCH_USE_CMPXCHG_LOCKREF
111	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
112	select ARCH_WANT_IPC_PARSE_VERSION
113	select BUILDTIME_EXTABLE_SORT
114	select CLONE_BACKWARDS2
115	select DYNAMIC_FTRACE if FUNCTION_TRACER
116	select GENERIC_CLOCKEVENTS
117	select GENERIC_CPU_AUTOPROBE
118	select GENERIC_CPU_VULNERABILITIES
119	select GENERIC_FIND_FIRST_BIT
120	select GENERIC_SMP_IDLE_THREAD
121	select GENERIC_TIME_VSYSCALL
122	select HAVE_ALIGNED_STRUCT_PAGE if SLUB
123	select HAVE_ARCH_AUDITSYSCALL
124	select HAVE_ARCH_JUMP_LABEL
125	select HAVE_ARCH_JUMP_LABEL_RELATIVE
126	select HAVE_ARCH_KASAN
127	select HAVE_ARCH_KASAN_VMALLOC
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_ASM_MODVERSIONS
135	select HAVE_EBPF_JIT if PACK_STACK && HAVE_MARCH_Z196_FEATURES
136	select HAVE_CMPXCHG_DOUBLE
137	select HAVE_CMPXCHG_LOCAL
138	select HAVE_COPY_THREAD_TLS
139	select HAVE_DEBUG_KMEMLEAK
140	select HAVE_DMA_CONTIGUOUS
141	select HAVE_DYNAMIC_FTRACE
142	select HAVE_DYNAMIC_FTRACE_WITH_REGS
143	select HAVE_FAST_GUP
144	select HAVE_EFFICIENT_UNALIGNED_ACCESS
145	select HAVE_FENTRY
146	select HAVE_FTRACE_MCOUNT_RECORD
147	select HAVE_FUNCTION_GRAPH_TRACER
148	select HAVE_FUNCTION_TRACER
149	select HAVE_FUTEX_CMPXCHG if FUTEX
150	select HAVE_GCC_PLUGINS
151	select HAVE_KERNEL_BZIP2
152	select HAVE_KERNEL_GZIP
153	select HAVE_KERNEL_LZ4
154	select HAVE_KERNEL_LZMA
155	select HAVE_KERNEL_LZO
156	select HAVE_KERNEL_UNCOMPRESSED
157	select HAVE_KERNEL_XZ
158	select HAVE_KPROBES
159	select HAVE_KRETPROBES
160	select HAVE_KVM
161	select HAVE_LIVEPATCH
162	select HAVE_PERF_REGS
163	select HAVE_PERF_USER_STACK_DUMP
164	select HAVE_MEMBLOCK_NODE_MAP
165	select HAVE_MEMBLOCK_PHYS_MAP
166	select HAVE_MMU_GATHER_NO_GATHER
167	select HAVE_MOD_ARCH_SPECIFIC
168	select HAVE_NOP_MCOUNT
169	select HAVE_OPROFILE
170	select HAVE_PCI
171	select HAVE_PERF_EVENTS
172	select HAVE_RCU_TABLE_FREE
173	select HAVE_REGS_AND_STACK_ACCESS_API
174	select HAVE_RELIABLE_STACKTRACE
175	select HAVE_RSEQ
176	select HAVE_SYSCALL_TRACEPOINTS
177	select HAVE_VIRT_CPU_ACCOUNTING
178	select IOMMU_HELPER		if PCI
179	select IOMMU_SUPPORT		if PCI
180	select MODULES_USE_ELF_RELA
181	select NEED_DMA_MAP_STATE	if PCI
182	select NEED_SG_DMA_LENGTH	if PCI
183	select OLD_SIGACTION
184	select OLD_SIGSUSPEND3
185	select PCI_DOMAINS		if PCI
186	select PCI_MSI			if PCI
187	select SPARSE_IRQ
188	select SYSCTL_EXCEPTION_TRACE
189	select THREAD_INFO_IN_TASK
190	select TTY
191	select VIRT_CPU_ACCOUNTING
192	select ARCH_HAS_SCALED_CPUTIME
193	select HAVE_NMI
194	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
195	select SWIOTLB
196	select GENERIC_ALLOCATOR
197
198
199config SCHED_OMIT_FRAME_POINTER
200	def_bool y
201
202config PGTABLE_LEVELS
203	int
204	default 5
205
206source "kernel/livepatch/Kconfig"
207
208menu "Processor type and features"
209
210config HAVE_MARCH_Z900_FEATURES
211	def_bool n
212
213config HAVE_MARCH_Z990_FEATURES
214	def_bool n
215	select HAVE_MARCH_Z900_FEATURES
216
217config HAVE_MARCH_Z9_109_FEATURES
218	def_bool n
219	select HAVE_MARCH_Z990_FEATURES
220
221config HAVE_MARCH_Z10_FEATURES
222	def_bool n
223	select HAVE_MARCH_Z9_109_FEATURES
224
225config HAVE_MARCH_Z196_FEATURES
226	def_bool n
227	select HAVE_MARCH_Z10_FEATURES
228
229config HAVE_MARCH_ZEC12_FEATURES
230	def_bool n
231	select HAVE_MARCH_Z196_FEATURES
232
233config HAVE_MARCH_Z13_FEATURES
234	def_bool n
235	select HAVE_MARCH_ZEC12_FEATURES
236
237config HAVE_MARCH_Z14_FEATURES
238	def_bool n
239	select HAVE_MARCH_Z13_FEATURES
240
241config HAVE_MARCH_Z15_FEATURES
242	def_bool n
243	select HAVE_MARCH_Z14_FEATURES
244
245choice
246	prompt "Processor type"
247	default MARCH_Z196
248
249config MARCH_Z900
250	bool "IBM zSeries model z800 and z900"
251	select HAVE_MARCH_Z900_FEATURES
252	depends on $(cc-option,-march=z900)
253	help
254	  Select this to enable optimizations for model z800/z900 (2064 and
255	  2066 series). This will enable some optimizations that are not
256	  available on older ESA/390 (31 Bit) only CPUs.
257
258config MARCH_Z990
259	bool "IBM zSeries model z890 and z990"
260	select HAVE_MARCH_Z990_FEATURES
261	depends on $(cc-option,-march=z990)
262	help
263	  Select this to enable optimizations for model z890/z990 (2084 and
264	  2086 series). The kernel will be slightly faster but will not work
265	  on older machines.
266
267config MARCH_Z9_109
268	bool "IBM System z9"
269	select HAVE_MARCH_Z9_109_FEATURES
270	depends on $(cc-option,-march=z9-109)
271	help
272	  Select this to enable optimizations for IBM System z9 (2094 and
273	  2096 series). The kernel will be slightly faster but will not work
274	  on older machines.
275
276config MARCH_Z10
277	bool "IBM System z10"
278	select HAVE_MARCH_Z10_FEATURES
279	depends on $(cc-option,-march=z10)
280	help
281	  Select this to enable optimizations for IBM System z10 (2097 and
282	  2098 series). The kernel will be slightly faster but will not work
283	  on older machines.
284
285config MARCH_Z196
286	bool "IBM zEnterprise 114 and 196"
287	select HAVE_MARCH_Z196_FEATURES
288	depends on $(cc-option,-march=z196)
289	help
290	  Select this to enable optimizations for IBM zEnterprise 114 and 196
291	  (2818 and 2817 series). The kernel will be slightly faster but will
292	  not work on older machines.
293
294config MARCH_ZEC12
295	bool "IBM zBC12 and zEC12"
296	select HAVE_MARCH_ZEC12_FEATURES
297	depends on $(cc-option,-march=zEC12)
298	help
299	  Select this to enable optimizations for IBM zBC12 and zEC12 (2828 and
300	  2827 series). The kernel will be slightly faster but will not work on
301	  older machines.
302
303config MARCH_Z13
304	bool "IBM z13s and z13"
305	select HAVE_MARCH_Z13_FEATURES
306	depends on $(cc-option,-march=z13)
307	help
308	  Select this to enable optimizations for IBM z13s and z13 (2965 and
309	  2964 series). The kernel will be slightly faster but will not work on
310	  older machines.
311
312config MARCH_Z14
313	bool "IBM z14 ZR1 and z14"
314	select HAVE_MARCH_Z14_FEATURES
315	depends on $(cc-option,-march=z14)
316	help
317	  Select this to enable optimizations for IBM z14 ZR1 and z14 (3907
318	  and 3906 series). The kernel will be slightly faster but will not
319	  work on older machines.
320
321config MARCH_Z15
322	bool "IBM z15"
323	select HAVE_MARCH_Z15_FEATURES
324	depends on $(cc-option,-march=z15)
325	help
326	  Select this to enable optimizations for IBM z15 (8562
327	  and 8561 series). The kernel will be slightly faster but will not
328	  work on older machines.
329
330endchoice
331
332config MARCH_Z900_TUNE
333	def_bool TUNE_Z900 || MARCH_Z900 && TUNE_DEFAULT
334
335config MARCH_Z990_TUNE
336	def_bool TUNE_Z990 || MARCH_Z990 && TUNE_DEFAULT
337
338config MARCH_Z9_109_TUNE
339	def_bool TUNE_Z9_109 || MARCH_Z9_109 && TUNE_DEFAULT
340
341config MARCH_Z10_TUNE
342	def_bool TUNE_Z10 || MARCH_Z10 && TUNE_DEFAULT
343
344config MARCH_Z196_TUNE
345	def_bool TUNE_Z196 || MARCH_Z196 && TUNE_DEFAULT
346
347config MARCH_ZEC12_TUNE
348	def_bool TUNE_ZEC12 || MARCH_ZEC12 && TUNE_DEFAULT
349
350config MARCH_Z13_TUNE
351	def_bool TUNE_Z13 || MARCH_Z13 && TUNE_DEFAULT
352
353config MARCH_Z14_TUNE
354	def_bool TUNE_Z14 || MARCH_Z14 && TUNE_DEFAULT
355
356config MARCH_Z15_TUNE
357	def_bool TUNE_Z15 || MARCH_Z15 && TUNE_DEFAULT
358
359choice
360	prompt "Tune code generation"
361	default TUNE_DEFAULT
362	help
363	  Cause the compiler to tune (-mtune) the generated code for a machine.
364	  This will make the code run faster on the selected machine but
365	  somewhat slower on other machines.
366	  This option only changes how the compiler emits instructions, not the
367	  selection of instructions itself, so the resulting kernel will run on
368	  all other machines.
369
370config TUNE_DEFAULT
371	bool "Default"
372	help
373	  Tune the generated code for the target processor for which the kernel
374	  will be compiled.
375
376config TUNE_Z900
377	bool "IBM zSeries model z800 and z900"
378	depends on $(cc-option,-mtune=z900)
379
380config TUNE_Z990
381	bool "IBM zSeries model z890 and z990"
382	depends on $(cc-option,-mtune=z990)
383
384config TUNE_Z9_109
385	bool "IBM System z9"
386	depends on $(cc-option,-mtune=z9-109)
387
388config TUNE_Z10
389	bool "IBM System z10"
390	depends on $(cc-option,-mtune=z10)
391
392config TUNE_Z196
393	bool "IBM zEnterprise 114 and 196"
394	depends on $(cc-option,-mtune=z196)
395
396config TUNE_ZEC12
397	bool "IBM zBC12 and zEC12"
398	depends on $(cc-option,-mtune=zEC12)
399
400config TUNE_Z13
401	bool "IBM z13s and z13"
402	depends on $(cc-option,-mtune=z13)
403
404config TUNE_Z14
405	bool "IBM z14 ZR1 and z14"
406	depends on $(cc-option,-mtune=z14)
407
408config TUNE_Z15
409	bool "IBM z15"
410	depends on $(cc-option,-mtune=z15)
411
412endchoice
413
414config 64BIT
415	def_bool y
416
417config COMPAT
418	def_bool y
419	prompt "Kernel support for 31 bit emulation"
420	select COMPAT_BINFMT_ELF if BINFMT_ELF
421	select ARCH_WANT_OLD_COMPAT_IPC
422	select COMPAT_OLD_SIGACTION
423	select HAVE_UID16
424	depends on MULTIUSER
425	help
426	  Select this option if you want to enable your system kernel to
427	  handle system-calls from ELF binaries for 31 bit ESA.  This option
428	  (and some other stuff like libraries and such) is needed for
429	  executing 31 bit applications.  It is safe to say "Y".
430
431config SYSVIPC_COMPAT
432	def_bool y if COMPAT && SYSVIPC
433
434config SMP
435	def_bool y
436
437config NR_CPUS
438	int "Maximum number of CPUs (2-512)"
439	range 2 512
440	default "64"
441	help
442	  This allows you to specify the maximum number of CPUs which this
443	  kernel will support. The maximum supported value is 512 and the
444	  minimum value which makes sense is 2.
445
446	  This is purely to save memory - each supported CPU adds
447	  approximately sixteen kilobytes to the kernel image.
448
449config HOTPLUG_CPU
450	def_bool y
451
452# Some NUMA nodes have memory ranges that span
453# other nodes.	Even though a pfn is valid and
454# between a node's start and end pfns, it may not
455# reside on that node.	See memmap_init_zone()
456# for details. <- They meant memory holes!
457config NODES_SPAN_OTHER_NODES
458	def_bool NUMA
459
460config NUMA
461	bool "NUMA support"
462	depends on SCHED_TOPOLOGY
463	default n
464	help
465	  Enable NUMA support
466
467	  This option adds NUMA support to the kernel.
468
469	  An operation mode can be selected by appending
470	  numa=<method> to the kernel command line.
471
472	  The default behaviour is identical to appending numa=plain to
473	  the command line. This will create just one node with all
474	  available memory and all CPUs in it.
475
476config NODES_SHIFT
477	int "Maximum NUMA nodes (as a power of 2)"
478	range 1 10
479	depends on NUMA
480	default "4"
481	help
482	  Specify the maximum number of NUMA nodes available on the target
483	  system. Increases memory reserved to accommodate various tables.
484
485menu "Select NUMA modes"
486	depends on NUMA
487
488config NUMA_EMU
489	bool "NUMA emulation"
490	default y
491	help
492	  Numa emulation mode will split the available system memory into
493	  equal chunks which then are distributed over the configured number
494	  of nodes in a round-robin manner.
495
496	  The number of fake nodes is limited by the number of available memory
497	  chunks (i.e. memory size / fake size) and the number of supported
498	  nodes in the kernel.
499
500	  The CPUs are assigned to the nodes in a way that partially respects
501	  the original machine topology (if supported by the machine).
502	  Fair distribution of the CPUs is not guaranteed.
503
504config EMU_SIZE
505	hex "NUMA emulation memory chunk size"
506	default 0x10000000
507	range 0x400000 0x100000000
508	depends on NUMA_EMU
509	help
510	  Select the default size by which the memory is chopped and then
511	  assigned to emulated NUMA nodes.
512
513	  This can be overridden by specifying
514
515	  emu_size=<n>
516
517	  on the kernel command line where also suffixes K, M, G, and T are
518	  supported.
519
520endmenu
521
522config SCHED_SMT
523	def_bool n
524
525config SCHED_MC
526	def_bool n
527
528config SCHED_BOOK
529	def_bool n
530
531config SCHED_DRAWER
532	def_bool n
533
534config SCHED_TOPOLOGY
535	def_bool y
536	prompt "Topology scheduler support"
537	select SCHED_SMT
538	select SCHED_MC
539	select SCHED_BOOK
540	select SCHED_DRAWER
541	help
542	  Topology scheduler support improves the CPU scheduler's decision
543	  making when dealing with machines that have multi-threading,
544	  multiple cores or multiple books.
545
546source "kernel/Kconfig.hz"
547
548config KEXEC
549	def_bool y
550	select KEXEC_CORE
551
552config KEXEC_FILE
553	bool "kexec file based system call"
554	select KEXEC_CORE
555	select BUILD_BIN2C
556	depends on CRYPTO
557	depends on CRYPTO_SHA256
558	depends on CRYPTO_SHA256_S390
559	help
560	  Enable the kexec file based system call. In contrast to the normal
561	  kexec system call this system call takes file descriptors for the
562	  kernel and initramfs as arguments.
563
564config ARCH_HAS_KEXEC_PURGATORY
565	def_bool y
566	depends on KEXEC_FILE
567
568config KEXEC_SIG
569	bool "Verify kernel signature during kexec_file_load() syscall"
570	depends on KEXEC_FILE && MODULE_SIG_FORMAT
571	help
572	  This option makes kernel signature verification mandatory for
573	  the kexec_file_load() syscall.
574
575	  In addition to that option, you need to enable signature
576	  verification for the corresponding kernel image type being
577	  loaded in order for this to work.
578
579config ARCH_RANDOM
580	def_bool y
581	prompt "s390 architectural random number generation API"
582	help
583	  Enable the s390 architectural random number generation API
584	  to provide random data for all consumers within the Linux
585	  kernel.
586
587	  When enabled the arch_random_* functions declared in linux/random.h
588	  are implemented. The implementation is based on the s390 CPACF
589	  instruction subfunction TRNG which provides a real true random
590	  number generator.
591
592	  If unsure, say Y.
593
594config KERNEL_NOBP
595	def_bool n
596	prompt "Enable modified branch prediction for the kernel by default"
597	help
598	  If this option is selected the kernel will switch to a modified
599	  branch prediction mode if the firmware interface is available.
600	  The modified branch prediction mode improves the behaviour in
601	  regard to speculative execution.
602
603	  With the option enabled the kernel parameter "nobp=0" or "nospec"
604	  can be used to run the kernel in the normal branch prediction mode.
605
606	  With the option disabled the modified branch prediction mode is
607	  enabled with the "nobp=1" kernel parameter.
608
609	  If unsure, say N.
610
611config EXPOLINE
612	def_bool n
613	prompt "Avoid speculative indirect branches in the kernel"
614	help
615	  Compile the kernel with the expoline compiler options to guard
616	  against kernel-to-user data leaks by avoiding speculative indirect
617	  branches.
618	  Requires a compiler with -mindirect-branch=thunk support for full
619	  protection. The kernel may run slower.
620
621	  If unsure, say N.
622
623choice
624	prompt "Expoline default"
625	depends on EXPOLINE
626	default EXPOLINE_FULL
627
628config EXPOLINE_OFF
629	bool "spectre_v2=off"
630
631config EXPOLINE_AUTO
632	bool "spectre_v2=auto"
633
634config EXPOLINE_FULL
635	bool "spectre_v2=on"
636
637endchoice
638
639config RELOCATABLE
640	bool "Build a relocatable kernel"
641	select MODULE_REL_CRCS if MODVERSIONS
642	default y
643	help
644	  This builds a kernel image that retains relocation information
645	  so it can be loaded at an arbitrary address.
646	  The kernel is linked as a position-independent executable (PIE)
647	  and contains dynamic relocations which are processed early in the
648	  bootup process.
649	  The relocations make the kernel image about 15% larger (compressed
650	  10%), but are discarded at runtime.
651
652config RANDOMIZE_BASE
653	bool "Randomize the address of the kernel image (KASLR)"
654	depends on RELOCATABLE
655	default y
656	help
657	  In support of Kernel Address Space Layout Randomization (KASLR),
658	  this randomizes the address at which the kernel image is loaded,
659	  as a security feature that deters exploit attempts relying on
660	  knowledge of the location of kernel internals.
661
662endmenu
663
664menu "Memory setup"
665
666config ARCH_SPARSEMEM_ENABLE
667	def_bool y
668	select SPARSEMEM_VMEMMAP_ENABLE
669	select SPARSEMEM_VMEMMAP
670
671config ARCH_SPARSEMEM_DEFAULT
672	def_bool y
673
674config ARCH_ENABLE_MEMORY_HOTPLUG
675	def_bool y if SPARSEMEM
676
677config ARCH_ENABLE_MEMORY_HOTREMOVE
678	def_bool y
679
680config ARCH_ENABLE_SPLIT_PMD_PTLOCK
681	def_bool y
682
683config FORCE_MAX_ZONEORDER
684	int
685	default "9"
686
687config MAX_PHYSMEM_BITS
688	int "Maximum size of supported physical memory in bits (42-53)"
689	range 42 53
690	default "46"
691	help
692	  This option specifies the maximum supported size of physical memory
693	  in bits. Supported is any size between 2^42 (4TB) and 2^53 (8PB).
694	  Increasing the number of bits also increases the kernel image size.
695	  By default 46 bits (64TB) are supported.
696
697config PACK_STACK
698	def_bool y
699	prompt "Pack kernel stack"
700	help
701	  This option enables the compiler option -mkernel-backchain if it
702	  is available. If the option is available the compiler supports
703	  the new stack layout which dramatically reduces the minimum stack
704	  frame size. With an old compiler a non-leaf function needs a
705	  minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
706	  -mkernel-backchain the minimum size drops to 16 byte on 31 bit
707	  and 24 byte on 64 bit.
708
709	  Say Y if you are unsure.
710
711config CHECK_STACK
712	def_bool y
713	depends on !VMAP_STACK
714	prompt "Detect kernel stack overflow"
715	help
716	  This option enables the compiler option -mstack-guard and
717	  -mstack-size if they are available. If the compiler supports them
718	  it will emit additional code to each function prolog to trigger
719	  an illegal operation if the kernel stack is about to overflow.
720
721	  Say N if you are unsure.
722
723config STACK_GUARD
724	int "Size of the guard area (128-1024)"
725	range 128 1024
726	depends on CHECK_STACK
727	default "256"
728	help
729	  This allows you to specify the size of the guard area at the lower
730	  end of the kernel stack. If the kernel stack points into the guard
731	  area on function entry an illegal operation is triggered. The size
732	  needs to be a power of 2. Please keep in mind that the size of an
733	  interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
734	  The minimum size for the stack guard should be 256 for 31 bit and
735	  512 for 64 bit.
736
737config WARN_DYNAMIC_STACK
738	def_bool n
739	prompt "Emit compiler warnings for function with dynamic stack usage"
740	help
741	  This option enables the compiler option -mwarn-dynamicstack. If the
742	  compiler supports this options generates warnings for functions
743	  that dynamically allocate stack space using alloca.
744
745	  Say N if you are unsure.
746
747endmenu
748
749menu "I/O subsystem"
750
751config QDIO
752	def_tristate y
753	prompt "QDIO support"
754	---help---
755	  This driver provides the Queued Direct I/O base support for
756	  IBM System z.
757
758	  To compile this driver as a module, choose M here: the
759	  module will be called qdio.
760
761	  If unsure, say Y.
762
763if PCI
764
765config PCI_NR_FUNCTIONS
766	int "Maximum number of PCI functions (1-4096)"
767	range 1 4096
768	default "128"
769	help
770	  This allows you to specify the maximum number of PCI functions which
771	  this kernel will support.
772
773endif # PCI
774
775config HAS_IOMEM
776	def_bool PCI
777
778config CHSC_SCH
779	def_tristate m
780	prompt "Support for CHSC subchannels"
781	help
782	  This driver allows usage of CHSC subchannels. A CHSC subchannel
783	  is usually present on LPAR only.
784	  The driver creates a device /dev/chsc, which may be used to
785	  obtain I/O configuration information about the machine and
786	  to issue asynchronous chsc commands (DANGEROUS).
787	  You will usually only want to use this interface on a special
788	  LPAR designated for system management.
789
790	  To compile this driver as a module, choose M here: the
791	  module will be called chsc_sch.
792
793	  If unsure, say N.
794
795config SCM_BUS
796	def_bool y
797	prompt "SCM bus driver"
798	help
799	  Bus driver for Storage Class Memory.
800
801config EADM_SCH
802	def_tristate m
803	prompt "Support for EADM subchannels"
804	depends on SCM_BUS
805	help
806	  This driver allows usage of EADM subchannels. EADM subchannels act
807	  as a communication vehicle for SCM increments.
808
809	  To compile this driver as a module, choose M here: the
810	  module will be called eadm_sch.
811
812config VFIO_CCW
813	def_tristate n
814	prompt "Support for VFIO-CCW subchannels"
815	depends on S390_CCW_IOMMU && VFIO_MDEV
816	help
817	  This driver allows usage of I/O subchannels via VFIO-CCW.
818
819	  To compile this driver as a module, choose M here: the
820	  module will be called vfio_ccw.
821
822config VFIO_AP
823	def_tristate n
824	prompt "VFIO support for AP devices"
825	depends on S390_AP_IOMMU && VFIO_MDEV_DEVICE && KVM
826	help
827		This driver grants access to Adjunct Processor (AP) devices
828		via the VFIO mediated device interface.
829
830		To compile this driver as a module, choose M here: the module
831		will be called vfio_ap.
832
833endmenu
834
835menu "Dump support"
836
837config CRASH_DUMP
838	bool "kernel crash dumps"
839	select KEXEC
840	help
841	  Generate crash dump after being started by kexec.
842	  Crash dump kernels are loaded in the main kernel with kexec-tools
843	  into a specially reserved region and then later executed after
844	  a crash by kdump/kexec.
845	  Refer to <file:Documentation/s390/zfcpdump.rst> for more details on this.
846	  This option also enables s390 zfcpdump.
847	  See also <file:Documentation/s390/zfcpdump.rst>
848
849endmenu
850
851config SECCOMP
852	def_bool y
853	prompt "Enable seccomp to safely compute untrusted bytecode"
854	depends on PROC_FS
855	help
856	  This kernel feature is useful for number crunching applications
857	  that may need to compute untrusted bytecode during their
858	  execution. By using pipes or other transports made available to
859	  the process as file descriptors supporting the read/write
860	  syscalls, it's possible to isolate those applications in
861	  their own address space using seccomp. Once seccomp is
862	  enabled via /proc/<pid>/seccomp, it cannot be disabled
863	  and the task is only allowed to execute a few safe syscalls
864	  defined by each seccomp mode.
865
866	  If unsure, say Y.
867
868menu "Power Management"
869
870config ARCH_HIBERNATION_POSSIBLE
871	def_bool y
872
873source "kernel/power/Kconfig"
874
875endmenu
876
877config CCW
878	def_bool y
879
880config HAVE_PNETID
881	tristate
882	default (SMC || CCWGROUP)
883
884menu "Virtualization"
885
886config PROTECTED_VIRTUALIZATION_GUEST
887	def_bool n
888	prompt "Protected virtualization guest support"
889	help
890	  Select this option, if you want to be able to run this
891	  kernel as a protected virtualization KVM guest.
892	  Protected virtualization capable machines have a mini hypervisor
893	  located at machine level (an ultravisor). With help of the
894	  Ultravisor, KVM will be able to run "protected" VMs, special
895	  VMs whose memory and management data are unavailable to KVM.
896
897config PFAULT
898	def_bool y
899	prompt "Pseudo page fault support"
900	help
901	  Select this option, if you want to use PFAULT pseudo page fault
902	  handling under VM. If running native or in LPAR, this option
903	  has no effect. If your VM does not support PFAULT, PAGEEX
904	  pseudo page fault handling will be used.
905	  Note that VM 4.2 supports PFAULT but has a bug in its
906	  implementation that causes some problems.
907	  Everybody who wants to run Linux under VM != VM4.2 should select
908	  this option.
909
910config CMM
911	def_tristate n
912	prompt "Cooperative memory management"
913	help
914	  Select this option, if you want to enable the kernel interface
915	  to reduce the memory size of the system. This is accomplished
916	  by allocating pages of memory and put them "on hold". This only
917	  makes sense for a system running under VM where the unused pages
918	  will be reused by VM for other guest systems. The interface
919	  allows an external monitor to balance memory of many systems.
920	  Everybody who wants to run Linux under VM should select this
921	  option.
922
923config CMM_IUCV
924	def_bool y
925	prompt "IUCV special message interface to cooperative memory management"
926	depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
927	help
928	  Select this option to enable the special message interface to
929	  the cooperative memory management.
930
931config APPLDATA_BASE
932	def_bool n
933	prompt "Linux - VM Monitor Stream, base infrastructure"
934	depends on PROC_FS
935	help
936	  This provides a kernel interface for creating and updating z/VM APPLDATA
937	  monitor records. The monitor records are updated at certain time
938	  intervals, once the timer is started.
939	  Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
940	  i.e. enables or disables monitoring on the Linux side.
941	  A custom interval value (in seconds) can be written to
942	  /proc/appldata/interval.
943
944	  Defaults are 60 seconds interval and timer off.
945	  The /proc entries can also be read from, showing the current settings.
946
947config APPLDATA_MEM
948	def_tristate m
949	prompt "Monitor memory management statistics"
950	depends on APPLDATA_BASE && VM_EVENT_COUNTERS
951	help
952	  This provides memory management related data to the Linux - VM Monitor
953	  Stream, like paging/swapping rate, memory utilisation, etc.
954	  Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
955	  APPLDATA monitor record, i.e. enables or disables monitoring this record
956	  on the z/VM side.
957
958	  Default is disabled.
959	  The /proc entry can also be read from, showing the current settings.
960
961	  This can also be compiled as a module, which will be called
962	  appldata_mem.o.
963
964config APPLDATA_OS
965	def_tristate m
966	prompt "Monitor OS statistics"
967	depends on APPLDATA_BASE
968	help
969	  This provides OS related data to the Linux - VM Monitor Stream, like
970	  CPU utilisation, etc.
971	  Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
972	  APPLDATA monitor record, i.e. enables or disables monitoring this record
973	  on the z/VM side.
974
975	  Default is disabled.
976	  This can also be compiled as a module, which will be called
977	  appldata_os.o.
978
979config APPLDATA_NET_SUM
980	def_tristate m
981	prompt "Monitor overall network statistics"
982	depends on APPLDATA_BASE && NET
983	help
984	  This provides network related data to the Linux - VM Monitor Stream,
985	  currently there is only a total sum of network I/O statistics, no
986	  per-interface data.
987	  Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
988	  APPLDATA monitor record, i.e. enables or disables monitoring this record
989	  on the z/VM side.
990
991	  Default is disabled.
992	  This can also be compiled as a module, which will be called
993	  appldata_net_sum.o.
994
995config S390_HYPFS_FS
996	def_bool y
997	prompt "s390 hypervisor file system support"
998	select SYS_HYPERVISOR
999	help
1000	  This is a virtual file system intended to provide accounting
1001	  information in an s390 hypervisor environment.
1002
1003source "arch/s390/kvm/Kconfig"
1004
1005config S390_GUEST
1006	def_bool y
1007	prompt "s390 support for virtio devices"
1008	select TTY
1009	select VIRTUALIZATION
1010	select VIRTIO
1011	select VIRTIO_CONSOLE
1012	help
1013	  Enabling this option adds support for virtio based paravirtual device
1014	  drivers on s390.
1015
1016	  Select this option if you want to run the kernel as a guest under
1017	  the KVM hypervisor.
1018
1019endmenu
1020
1021menu "Selftests"
1022
1023config S390_UNWIND_SELFTEST
1024	def_tristate n
1025	prompt "Test unwind functions"
1026	help
1027	  This option enables s390 specific stack unwinder testing kernel
1028	  module. This option is not useful for distributions or general
1029	  kernels, but only for kernel developers working on architecture code.
1030
1031	  Say N if you are unsure.
1032
1033endmenu
1034