xref: /openbmc/linux/arch/s390/Kconfig (revision 1d7a0395)
1# SPDX-License-Identifier: GPL-2.0
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	# Note: keep this list sorted alphabetically
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_NUMA_BALANCING
114	select ARCH_USE_BUILTIN_BSWAP
115	select ARCH_USE_CMPXCHG_LOCKREF
116	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
117	select ARCH_WANTS_NO_INSTR
118	select ARCH_WANT_DEFAULT_BPF_JIT
119	select ARCH_WANT_IPC_PARSE_VERSION
120	select BUILDTIME_TABLE_SORT
121	select CLONE_BACKWARDS2
122	select CPU_NO_EFFICIENT_FFS if !HAVE_MARCH_Z9_109_FEATURES
123	select DMA_OPS if PCI
124	select DYNAMIC_FTRACE if FUNCTION_TRACER
125	select GENERIC_ALLOCATOR
126	select GENERIC_CPU_AUTOPROBE
127	select GENERIC_CPU_VULNERABILITIES
128	select GENERIC_ENTRY
129	select GENERIC_FIND_FIRST_BIT
130	select GENERIC_GETTIMEOFDAY
131	select GENERIC_PTDUMP
132	select GENERIC_SMP_IDLE_THREAD
133	select GENERIC_TIME_VSYSCALL
134	select GENERIC_VDSO_TIME_NS
135	select HAVE_ALIGNED_STRUCT_PAGE if SLUB
136	select HAVE_ARCH_AUDITSYSCALL
137	select HAVE_ARCH_JUMP_LABEL
138	select HAVE_ARCH_JUMP_LABEL_RELATIVE
139	select HAVE_ARCH_KASAN
140	select HAVE_ARCH_KASAN_VMALLOC
141	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
142	select HAVE_ARCH_SECCOMP_FILTER
143	select HAVE_ARCH_SOFT_DIRTY
144	select HAVE_ARCH_TRACEHOOK
145	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
146	select HAVE_ARCH_VMAP_STACK
147	select HAVE_ASM_MODVERSIONS
148	select HAVE_CMPXCHG_DOUBLE
149	select HAVE_CMPXCHG_LOCAL
150	select HAVE_DEBUG_KMEMLEAK
151	select HAVE_DMA_CONTIGUOUS
152	select HAVE_DYNAMIC_FTRACE
153	select HAVE_DYNAMIC_FTRACE_WITH_REGS
154	select HAVE_EBPF_JIT if PACK_STACK && HAVE_MARCH_Z196_FEATURES
155	select HAVE_EFFICIENT_UNALIGNED_ACCESS
156	select HAVE_FAST_GUP
157	select HAVE_FENTRY
158	select HAVE_FTRACE_MCOUNT_RECORD
159	select HAVE_FUNCTION_ERROR_INJECTION
160	select HAVE_FUNCTION_GRAPH_TRACER
161	select HAVE_FUNCTION_TRACER
162	select HAVE_FUTEX_CMPXCHG if FUTEX
163	select HAVE_GCC_PLUGINS
164	select HAVE_GENERIC_VDSO
165	select HAVE_IRQ_EXIT_ON_IRQ_STACK
166	select HAVE_KERNEL_BZIP2
167	select HAVE_KERNEL_GZIP
168	select HAVE_KERNEL_LZ4
169	select HAVE_KERNEL_LZMA
170	select HAVE_KERNEL_LZO
171	select HAVE_KERNEL_UNCOMPRESSED
172	select HAVE_KERNEL_XZ
173	select HAVE_KPROBES
174	select HAVE_KPROBES_ON_FTRACE
175	select HAVE_KRETPROBES
176	select HAVE_KVM
177	select HAVE_LIVEPATCH
178	select HAVE_MEMBLOCK_PHYS_MAP
179	select HAVE_MOD_ARCH_SPECIFIC
180	select HAVE_NMI
181	select HAVE_NOP_MCOUNT
182	select HAVE_PCI
183	select HAVE_PERF_EVENTS
184	select HAVE_PERF_REGS
185	select HAVE_PERF_USER_STACK_DUMP
186	select HAVE_REGS_AND_STACK_ACCESS_API
187	select HAVE_RELIABLE_STACKTRACE
188	select HAVE_RSEQ
189	select HAVE_SOFTIRQ_ON_OWN_STACK
190	select HAVE_SYSCALL_TRACEPOINTS
191	select HAVE_VIRT_CPU_ACCOUNTING
192	select HAVE_VIRT_CPU_ACCOUNTING_IDLE
193	select IOMMU_HELPER		if PCI
194	select IOMMU_SUPPORT		if PCI
195	select MMU_GATHER_NO_GATHER
196	select MMU_GATHER_RCU_TABLE_FREE
197	select MODULES_USE_ELF_RELA
198	select NEED_DMA_MAP_STATE	if PCI
199	select NEED_SG_DMA_LENGTH	if PCI
200	select OLD_SIGACTION
201	select OLD_SIGSUSPEND3
202	select PCI_DOMAINS		if PCI
203	select PCI_MSI			if PCI
204	select PCI_MSI_ARCH_FALLBACKS	if PCI_MSI
205	select SPARSE_IRQ
206	select SWIOTLB
207	select SYSCTL_EXCEPTION_TRACE
208	select THREAD_INFO_IN_TASK
209	select TTY
210	select VIRT_CPU_ACCOUNTING
211	select ZONE_DMA
212	# Note: keep the above list sorted alphabetically
213
214config SCHED_OMIT_FRAME_POINTER
215	def_bool y
216
217config PGTABLE_LEVELS
218	int
219	default 5
220
221source "kernel/livepatch/Kconfig"
222
223menu "Processor type and features"
224
225config HAVE_MARCH_Z900_FEATURES
226	def_bool n
227
228config HAVE_MARCH_Z990_FEATURES
229	def_bool n
230	select HAVE_MARCH_Z900_FEATURES
231
232config HAVE_MARCH_Z9_109_FEATURES
233	def_bool n
234	select HAVE_MARCH_Z990_FEATURES
235
236config HAVE_MARCH_Z10_FEATURES
237	def_bool n
238	select HAVE_MARCH_Z9_109_FEATURES
239
240config HAVE_MARCH_Z196_FEATURES
241	def_bool n
242	select HAVE_MARCH_Z10_FEATURES
243
244config HAVE_MARCH_ZEC12_FEATURES
245	def_bool n
246	select HAVE_MARCH_Z196_FEATURES
247
248config HAVE_MARCH_Z13_FEATURES
249	def_bool n
250	select HAVE_MARCH_ZEC12_FEATURES
251
252config HAVE_MARCH_Z14_FEATURES
253	def_bool n
254	select HAVE_MARCH_Z13_FEATURES
255
256config HAVE_MARCH_Z15_FEATURES
257	def_bool n
258	select HAVE_MARCH_Z14_FEATURES
259
260choice
261	prompt "Processor type"
262	default MARCH_Z196
263
264config MARCH_Z900
265	bool "IBM zSeries model z800 and z900"
266	select HAVE_MARCH_Z900_FEATURES
267	depends on $(cc-option,-march=z900)
268	help
269	  Select this to enable optimizations for model z800/z900 (2064 and
270	  2066 series). This will enable some optimizations that are not
271	  available on older ESA/390 (31 Bit) only CPUs.
272
273config MARCH_Z990
274	bool "IBM zSeries model z890 and z990"
275	select HAVE_MARCH_Z990_FEATURES
276	depends on $(cc-option,-march=z990)
277	help
278	  Select this to enable optimizations for model z890/z990 (2084 and
279	  2086 series). The kernel will be slightly faster but will not work
280	  on older machines.
281
282config MARCH_Z9_109
283	bool "IBM System z9"
284	select HAVE_MARCH_Z9_109_FEATURES
285	depends on $(cc-option,-march=z9-109)
286	help
287	  Select this to enable optimizations for IBM System z9 (2094 and
288	  2096 series). The kernel will be slightly faster but will not work
289	  on older machines.
290
291config MARCH_Z10
292	bool "IBM System z10"
293	select HAVE_MARCH_Z10_FEATURES
294	depends on $(cc-option,-march=z10)
295	help
296	  Select this to enable optimizations for IBM System z10 (2097 and
297	  2098 series). The kernel will be slightly faster but will not work
298	  on older machines.
299
300config MARCH_Z196
301	bool "IBM zEnterprise 114 and 196"
302	select HAVE_MARCH_Z196_FEATURES
303	depends on $(cc-option,-march=z196)
304	help
305	  Select this to enable optimizations for IBM zEnterprise 114 and 196
306	  (2818 and 2817 series). The kernel will be slightly faster but will
307	  not work on older machines.
308
309config MARCH_ZEC12
310	bool "IBM zBC12 and zEC12"
311	select HAVE_MARCH_ZEC12_FEATURES
312	depends on $(cc-option,-march=zEC12)
313	help
314	  Select this to enable optimizations for IBM zBC12 and zEC12 (2828 and
315	  2827 series). The kernel will be slightly faster but will not work on
316	  older machines.
317
318config MARCH_Z13
319	bool "IBM z13s and z13"
320	select HAVE_MARCH_Z13_FEATURES
321	depends on $(cc-option,-march=z13)
322	help
323	  Select this to enable optimizations for IBM z13s and z13 (2965 and
324	  2964 series). The kernel will be slightly faster but will not work on
325	  older machines.
326
327config MARCH_Z14
328	bool "IBM z14 ZR1 and z14"
329	select HAVE_MARCH_Z14_FEATURES
330	depends on $(cc-option,-march=z14)
331	help
332	  Select this to enable optimizations for IBM z14 ZR1 and z14 (3907
333	  and 3906 series). The kernel will be slightly faster but will not
334	  work on older machines.
335
336config MARCH_Z15
337	bool "IBM z15"
338	select HAVE_MARCH_Z15_FEATURES
339	depends on $(cc-option,-march=z15)
340	help
341	  Select this to enable optimizations for IBM z15 (8562
342	  and 8561 series). The kernel will be slightly faster but will not
343	  work on older machines.
344
345endchoice
346
347config MARCH_Z900_TUNE
348	def_bool TUNE_Z900 || MARCH_Z900 && TUNE_DEFAULT
349
350config MARCH_Z990_TUNE
351	def_bool TUNE_Z990 || MARCH_Z990 && TUNE_DEFAULT
352
353config MARCH_Z9_109_TUNE
354	def_bool TUNE_Z9_109 || MARCH_Z9_109 && TUNE_DEFAULT
355
356config MARCH_Z10_TUNE
357	def_bool TUNE_Z10 || MARCH_Z10 && TUNE_DEFAULT
358
359config MARCH_Z196_TUNE
360	def_bool TUNE_Z196 || MARCH_Z196 && TUNE_DEFAULT
361
362config MARCH_ZEC12_TUNE
363	def_bool TUNE_ZEC12 || MARCH_ZEC12 && TUNE_DEFAULT
364
365config MARCH_Z13_TUNE
366	def_bool TUNE_Z13 || MARCH_Z13 && TUNE_DEFAULT
367
368config MARCH_Z14_TUNE
369	def_bool TUNE_Z14 || MARCH_Z14 && TUNE_DEFAULT
370
371config MARCH_Z15_TUNE
372	def_bool TUNE_Z15 || MARCH_Z15 && TUNE_DEFAULT
373
374choice
375	prompt "Tune code generation"
376	default TUNE_DEFAULT
377	help
378	  Cause the compiler to tune (-mtune) the generated code for a machine.
379	  This will make the code run faster on the selected machine but
380	  somewhat slower on other machines.
381	  This option only changes how the compiler emits instructions, not the
382	  selection of instructions itself, so the resulting kernel will run on
383	  all other machines.
384
385config TUNE_DEFAULT
386	bool "Default"
387	help
388	  Tune the generated code for the target processor for which the kernel
389	  will be compiled.
390
391config TUNE_Z900
392	bool "IBM zSeries model z800 and z900"
393	depends on $(cc-option,-mtune=z900)
394
395config TUNE_Z990
396	bool "IBM zSeries model z890 and z990"
397	depends on $(cc-option,-mtune=z990)
398
399config TUNE_Z9_109
400	bool "IBM System z9"
401	depends on $(cc-option,-mtune=z9-109)
402
403config TUNE_Z10
404	bool "IBM System z10"
405	depends on $(cc-option,-mtune=z10)
406
407config TUNE_Z196
408	bool "IBM zEnterprise 114 and 196"
409	depends on $(cc-option,-mtune=z196)
410
411config TUNE_ZEC12
412	bool "IBM zBC12 and zEC12"
413	depends on $(cc-option,-mtune=zEC12)
414
415config TUNE_Z13
416	bool "IBM z13s and z13"
417	depends on $(cc-option,-mtune=z13)
418
419config TUNE_Z14
420	bool "IBM z14 ZR1 and z14"
421	depends on $(cc-option,-mtune=z14)
422
423config TUNE_Z15
424	bool "IBM z15"
425	depends on $(cc-option,-mtune=z15)
426
427endchoice
428
429config 64BIT
430	def_bool y
431
432config COMPAT
433	def_bool y
434	prompt "Kernel support for 31 bit emulation"
435	select ARCH_WANT_OLD_COMPAT_IPC
436	select COMPAT_OLD_SIGACTION
437	select HAVE_UID16
438	depends on MULTIUSER
439	help
440	  Select this option if you want to enable your system kernel to
441	  handle system-calls from ELF binaries for 31 bit ESA.  This option
442	  (and some other stuff like libraries and such) is needed for
443	  executing 31 bit applications.  It is safe to say "Y".
444
445config SYSVIPC_COMPAT
446	def_bool y if COMPAT && SYSVIPC
447
448config SMP
449	def_bool y
450
451config NR_CPUS
452	int "Maximum number of CPUs (2-512)"
453	range 2 512
454	default "64"
455	help
456	  This allows you to specify the maximum number of CPUs which this
457	  kernel will support. The maximum supported value is 512 and the
458	  minimum value which makes sense is 2.
459
460	  This is purely to save memory - each supported CPU adds
461	  approximately sixteen kilobytes to the kernel image.
462
463config HOTPLUG_CPU
464	def_bool y
465
466config NUMA
467	bool "NUMA support"
468	depends on SCHED_TOPOLOGY
469	default n
470	help
471	  Enable NUMA support
472
473	  This option adds NUMA support to the kernel.
474
475config NODES_SHIFT
476	int
477	depends on NUMA
478	default "1"
479
480config SCHED_SMT
481	def_bool n
482
483config SCHED_MC
484	def_bool n
485
486config SCHED_BOOK
487	def_bool n
488
489config SCHED_DRAWER
490	def_bool n
491
492config SCHED_TOPOLOGY
493	def_bool y
494	prompt "Topology scheduler support"
495	select SCHED_SMT
496	select SCHED_MC
497	select SCHED_BOOK
498	select SCHED_DRAWER
499	help
500	  Topology scheduler support improves the CPU scheduler's decision
501	  making when dealing with machines that have multi-threading,
502	  multiple cores or multiple books.
503
504source "kernel/Kconfig.hz"
505
506config KEXEC
507	def_bool y
508	select KEXEC_CORE
509
510config KEXEC_FILE
511	bool "kexec file based system call"
512	select KEXEC_CORE
513	select BUILD_BIN2C
514	depends on CRYPTO
515	depends on CRYPTO_SHA256
516	depends on CRYPTO_SHA256_S390
517	help
518	  Enable the kexec file based system call. In contrast to the normal
519	  kexec system call this system call takes file descriptors for the
520	  kernel and initramfs as arguments.
521
522config ARCH_HAS_KEXEC_PURGATORY
523	def_bool y
524	depends on KEXEC_FILE
525
526config KEXEC_SIG
527	bool "Verify kernel signature during kexec_file_load() syscall"
528	depends on KEXEC_FILE && MODULE_SIG_FORMAT
529	help
530	  This option makes kernel signature verification mandatory for
531	  the kexec_file_load() syscall.
532
533	  In addition to that option, you need to enable signature
534	  verification for the corresponding kernel image type being
535	  loaded in order for this to work.
536
537config ARCH_RANDOM
538	def_bool y
539	prompt "s390 architectural random number generation API"
540	help
541	  Enable the s390 architectural random number generation API
542	  to provide random data for all consumers within the Linux
543	  kernel.
544
545	  When enabled the arch_random_* functions declared in linux/random.h
546	  are implemented. The implementation is based on the s390 CPACF
547	  instruction subfunction TRNG which provides a real true random
548	  number generator.
549
550	  If unsure, say Y.
551
552config KERNEL_NOBP
553	def_bool n
554	prompt "Enable modified branch prediction for the kernel by default"
555	help
556	  If this option is selected the kernel will switch to a modified
557	  branch prediction mode if the firmware interface is available.
558	  The modified branch prediction mode improves the behaviour in
559	  regard to speculative execution.
560
561	  With the option enabled the kernel parameter "nobp=0" or "nospec"
562	  can be used to run the kernel in the normal branch prediction mode.
563
564	  With the option disabled the modified branch prediction mode is
565	  enabled with the "nobp=1" kernel parameter.
566
567	  If unsure, say N.
568
569config EXPOLINE
570	def_bool n
571	prompt "Avoid speculative indirect branches in the kernel"
572	help
573	  Compile the kernel with the expoline compiler options to guard
574	  against kernel-to-user data leaks by avoiding speculative indirect
575	  branches.
576	  Requires a compiler with -mindirect-branch=thunk support for full
577	  protection. The kernel may run slower.
578
579	  If unsure, say N.
580
581choice
582	prompt "Expoline default"
583	depends on EXPOLINE
584	default EXPOLINE_FULL
585
586config EXPOLINE_OFF
587	bool "spectre_v2=off"
588
589config EXPOLINE_AUTO
590	bool "spectre_v2=auto"
591
592config EXPOLINE_FULL
593	bool "spectre_v2=on"
594
595endchoice
596
597config RELOCATABLE
598	bool "Build a relocatable kernel"
599	select MODULE_REL_CRCS if MODVERSIONS
600	default y
601	help
602	  This builds a kernel image that retains relocation information
603	  so it can be loaded at an arbitrary address.
604	  The kernel is linked as a position-independent executable (PIE)
605	  and contains dynamic relocations which are processed early in the
606	  bootup process.
607	  The relocations make the kernel image about 15% larger (compressed
608	  10%), but are discarded at runtime.
609
610config RANDOMIZE_BASE
611	bool "Randomize the address of the kernel image (KASLR)"
612	depends on RELOCATABLE
613	default y
614	help
615	  In support of Kernel Address Space Layout Randomization (KASLR),
616	  this randomizes the address at which the kernel image is loaded,
617	  as a security feature that deters exploit attempts relying on
618	  knowledge of the location of kernel internals.
619
620endmenu
621
622menu "Memory setup"
623
624config ARCH_SPARSEMEM_ENABLE
625	def_bool y
626	select SPARSEMEM_VMEMMAP_ENABLE
627	select SPARSEMEM_VMEMMAP
628
629config ARCH_SPARSEMEM_DEFAULT
630	def_bool y
631
632config MAX_PHYSMEM_BITS
633	int "Maximum size of supported physical memory in bits (42-53)"
634	range 42 53
635	default "46"
636	help
637	  This option specifies the maximum supported size of physical memory
638	  in bits. Supported is any size between 2^42 (4TB) and 2^53 (8PB).
639	  Increasing the number of bits also increases the kernel image size.
640	  By default 46 bits (64TB) are supported.
641
642config PACK_STACK
643	def_bool y
644	prompt "Pack kernel stack"
645	help
646	  This option enables the compiler option -mkernel-backchain if it
647	  is available. If the option is available the compiler supports
648	  the new stack layout which dramatically reduces the minimum stack
649	  frame size. With an old compiler a non-leaf function needs a
650	  minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
651	  -mkernel-backchain the minimum size drops to 16 byte on 31 bit
652	  and 24 byte on 64 bit.
653
654	  Say Y if you are unsure.
655
656config CHECK_STACK
657	def_bool y
658	depends on !VMAP_STACK
659	prompt "Detect kernel stack overflow"
660	help
661	  This option enables the compiler option -mstack-guard and
662	  -mstack-size if they are available. If the compiler supports them
663	  it will emit additional code to each function prolog to trigger
664	  an illegal operation if the kernel stack is about to overflow.
665
666	  Say N if you are unsure.
667
668config STACK_GUARD
669	int "Size of the guard area (128-1024)"
670	range 128 1024
671	depends on CHECK_STACK
672	default "256"
673	help
674	  This allows you to specify the size of the guard area at the lower
675	  end of the kernel stack. If the kernel stack points into the guard
676	  area on function entry an illegal operation is triggered. The size
677	  needs to be a power of 2. Please keep in mind that the size of an
678	  interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
679	  The minimum size for the stack guard should be 256 for 31 bit and
680	  512 for 64 bit.
681
682config WARN_DYNAMIC_STACK
683	def_bool n
684	prompt "Emit compiler warnings for function with dynamic stack usage"
685	help
686	  This option enables the compiler option -mwarn-dynamicstack. If the
687	  compiler supports this options generates warnings for functions
688	  that dynamically allocate stack space using alloca.
689
690	  Say N if you are unsure.
691
692endmenu
693
694menu "I/O subsystem"
695
696config QDIO
697	def_tristate y
698	prompt "QDIO support"
699	help
700	  This driver provides the Queued Direct I/O base support for
701	  IBM System z.
702
703	  To compile this driver as a module, choose M here: the
704	  module will be called qdio.
705
706	  If unsure, say Y.
707
708if PCI
709
710config PCI_NR_FUNCTIONS
711	int "Maximum number of PCI functions (1-4096)"
712	range 1 4096
713	default "512"
714	help
715	  This allows you to specify the maximum number of PCI functions which
716	  this kernel will support.
717
718endif # PCI
719
720config HAS_IOMEM
721	def_bool PCI
722
723config CHSC_SCH
724	def_tristate m
725	prompt "Support for CHSC subchannels"
726	help
727	  This driver allows usage of CHSC subchannels. A CHSC subchannel
728	  is usually present on LPAR only.
729	  The driver creates a device /dev/chsc, which may be used to
730	  obtain I/O configuration information about the machine and
731	  to issue asynchronous chsc commands (DANGEROUS).
732	  You will usually only want to use this interface on a special
733	  LPAR designated for system management.
734
735	  To compile this driver as a module, choose M here: the
736	  module will be called chsc_sch.
737
738	  If unsure, say N.
739
740config SCM_BUS
741	def_bool y
742	prompt "SCM bus driver"
743	help
744	  Bus driver for Storage Class Memory.
745
746config EADM_SCH
747	def_tristate m
748	prompt "Support for EADM subchannels"
749	depends on SCM_BUS
750	help
751	  This driver allows usage of EADM subchannels. EADM subchannels act
752	  as a communication vehicle for SCM increments.
753
754	  To compile this driver as a module, choose M here: the
755	  module will be called eadm_sch.
756
757config VFIO_CCW
758	def_tristate n
759	prompt "Support for VFIO-CCW subchannels"
760	depends on S390_CCW_IOMMU && VFIO_MDEV
761	help
762	  This driver allows usage of I/O subchannels via VFIO-CCW.
763
764	  To compile this driver as a module, choose M here: the
765	  module will be called vfio_ccw.
766
767config VFIO_AP
768	def_tristate n
769	prompt "VFIO support for AP devices"
770	depends on S390_AP_IOMMU && VFIO_MDEV_DEVICE && KVM
771	depends on ZCRYPT
772	help
773		This driver grants access to Adjunct Processor (AP) devices
774		via the VFIO mediated device interface.
775
776		To compile this driver as a module, choose M here: the module
777		will be called vfio_ap.
778
779endmenu
780
781menu "Dump support"
782
783config CRASH_DUMP
784	bool "kernel crash dumps"
785	select KEXEC
786	help
787	  Generate crash dump after being started by kexec.
788	  Crash dump kernels are loaded in the main kernel with kexec-tools
789	  into a specially reserved region and then later executed after
790	  a crash by kdump/kexec.
791	  Refer to <file:Documentation/s390/zfcpdump.rst> for more details on this.
792	  This option also enables s390 zfcpdump.
793	  See also <file:Documentation/s390/zfcpdump.rst>
794
795endmenu
796
797config CCW
798	def_bool y
799
800config HAVE_PNETID
801	tristate
802	default (SMC || CCWGROUP)
803
804menu "Virtualization"
805
806config PROTECTED_VIRTUALIZATION_GUEST
807	def_bool n
808	prompt "Protected virtualization guest support"
809	select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
810	help
811	  Select this option, if you want to be able to run this
812	  kernel as a protected virtualization KVM guest.
813	  Protected virtualization capable machines have a mini hypervisor
814	  located at machine level (an ultravisor). With help of the
815	  Ultravisor, KVM will be able to run "protected" VMs, special
816	  VMs whose memory and management data are unavailable to KVM.
817
818config PFAULT
819	def_bool y
820	prompt "Pseudo page fault support"
821	help
822	  Select this option, if you want to use PFAULT pseudo page fault
823	  handling under VM. If running native or in LPAR, this option
824	  has no effect. If your VM does not support PFAULT, PAGEEX
825	  pseudo page fault handling will be used.
826	  Note that VM 4.2 supports PFAULT but has a bug in its
827	  implementation that causes some problems.
828	  Everybody who wants to run Linux under VM != VM4.2 should select
829	  this option.
830
831config CMM
832	def_tristate n
833	prompt "Cooperative memory management"
834	help
835	  Select this option, if you want to enable the kernel interface
836	  to reduce the memory size of the system. This is accomplished
837	  by allocating pages of memory and put them "on hold". This only
838	  makes sense for a system running under VM where the unused pages
839	  will be reused by VM for other guest systems. The interface
840	  allows an external monitor to balance memory of many systems.
841	  Everybody who wants to run Linux under VM should select this
842	  option.
843
844config CMM_IUCV
845	def_bool y
846	prompt "IUCV special message interface to cooperative memory management"
847	depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
848	help
849	  Select this option to enable the special message interface to
850	  the cooperative memory management.
851
852config APPLDATA_BASE
853	def_bool n
854	prompt "Linux - VM Monitor Stream, base infrastructure"
855	depends on PROC_FS
856	help
857	  This provides a kernel interface for creating and updating z/VM APPLDATA
858	  monitor records. The monitor records are updated at certain time
859	  intervals, once the timer is started.
860	  Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
861	  i.e. enables or disables monitoring on the Linux side.
862	  A custom interval value (in seconds) can be written to
863	  /proc/appldata/interval.
864
865	  Defaults are 60 seconds interval and timer off.
866	  The /proc entries can also be read from, showing the current settings.
867
868config APPLDATA_MEM
869	def_tristate m
870	prompt "Monitor memory management statistics"
871	depends on APPLDATA_BASE && VM_EVENT_COUNTERS
872	help
873	  This provides memory management related data to the Linux - VM Monitor
874	  Stream, like paging/swapping rate, memory utilisation, etc.
875	  Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
876	  APPLDATA monitor record, i.e. enables or disables monitoring this record
877	  on the z/VM side.
878
879	  Default is disabled.
880	  The /proc entry can also be read from, showing the current settings.
881
882	  This can also be compiled as a module, which will be called
883	  appldata_mem.o.
884
885config APPLDATA_OS
886	def_tristate m
887	prompt "Monitor OS statistics"
888	depends on APPLDATA_BASE
889	help
890	  This provides OS related data to the Linux - VM Monitor Stream, like
891	  CPU utilisation, etc.
892	  Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
893	  APPLDATA monitor record, i.e. enables or disables monitoring this record
894	  on the z/VM side.
895
896	  Default is disabled.
897	  This can also be compiled as a module, which will be called
898	  appldata_os.o.
899
900config APPLDATA_NET_SUM
901	def_tristate m
902	prompt "Monitor overall network statistics"
903	depends on APPLDATA_BASE && NET
904	help
905	  This provides network related data to the Linux - VM Monitor Stream,
906	  currently there is only a total sum of network I/O statistics, no
907	  per-interface data.
908	  Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
909	  APPLDATA monitor record, i.e. enables or disables monitoring this record
910	  on the z/VM side.
911
912	  Default is disabled.
913	  This can also be compiled as a module, which will be called
914	  appldata_net_sum.o.
915
916config S390_HYPFS_FS
917	def_bool y
918	prompt "s390 hypervisor file system support"
919	select SYS_HYPERVISOR
920	help
921	  This is a virtual file system intended to provide accounting
922	  information in an s390 hypervisor environment.
923
924source "arch/s390/kvm/Kconfig"
925
926config S390_GUEST
927	def_bool y
928	prompt "s390 support for virtio devices"
929	select TTY
930	select VIRTUALIZATION
931	select VIRTIO
932	help
933	  Enabling this option adds support for virtio based paravirtual device
934	  drivers on s390.
935
936	  Select this option if you want to run the kernel as a guest under
937	  the KVM hypervisor.
938
939endmenu
940
941menu "Selftests"
942
943config S390_UNWIND_SELFTEST
944	def_tristate n
945	prompt "Test unwind functions"
946	help
947	  This option enables s390 specific stack unwinder testing kernel
948	  module. This option is not useful for distributions or general
949	  kernels, but only for kernel developers working on architecture code.
950
951	  Say N if you are unsure.
952
953endmenu
954