xref: /openbmc/linux/arch/s390/Kconfig (revision 55b37d9c)
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 0x1C000000000000
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 ALTERNATE_USER_ADDRESS_SPACE
59	select ARCH_32BIT_USTAT_F_TINODE
60	select ARCH_BINFMT_ELF_STATE
61	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
62	select ARCH_ENABLE_MEMORY_HOTPLUG if SPARSEMEM
63	select ARCH_ENABLE_MEMORY_HOTREMOVE
64	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
65	select ARCH_HAS_CURRENT_STACK_POINTER
66	select ARCH_HAS_DEBUG_VM_PGTABLE
67	select ARCH_HAS_DEBUG_WX
68	select ARCH_HAS_DEVMEM_IS_ALLOWED
69	select ARCH_HAS_ELF_RANDOMIZE
70	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
71	select ARCH_HAS_FORTIFY_SOURCE
72	select ARCH_HAS_GCOV_PROFILE_ALL
73	select ARCH_HAS_GIGANTIC_PAGE
74	select ARCH_HAS_KCOV
75	select ARCH_HAS_MEMBARRIER_SYNC_CORE
76	select ARCH_HAS_MEM_ENCRYPT
77	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
78	select ARCH_HAS_PTE_SPECIAL
79	select ARCH_HAS_SCALED_CPUTIME
80	select ARCH_HAS_SET_DIRECT_MAP
81	select ARCH_HAS_SET_MEMORY
82	select ARCH_HAS_STRICT_KERNEL_RWX
83	select ARCH_HAS_STRICT_MODULE_RWX
84	select ARCH_HAS_SYSCALL_WRAPPER
85	select ARCH_HAS_UBSAN_SANITIZE_ALL
86	select ARCH_HAS_VDSO_DATA
87	select ARCH_HAVE_NMI_SAFE_CMPXCHG
88	select ARCH_INLINE_READ_LOCK
89	select ARCH_INLINE_READ_LOCK_BH
90	select ARCH_INLINE_READ_LOCK_IRQ
91	select ARCH_INLINE_READ_LOCK_IRQSAVE
92	select ARCH_INLINE_READ_TRYLOCK
93	select ARCH_INLINE_READ_UNLOCK
94	select ARCH_INLINE_READ_UNLOCK_BH
95	select ARCH_INLINE_READ_UNLOCK_IRQ
96	select ARCH_INLINE_READ_UNLOCK_IRQRESTORE
97	select ARCH_INLINE_SPIN_LOCK
98	select ARCH_INLINE_SPIN_LOCK_BH
99	select ARCH_INLINE_SPIN_LOCK_IRQ
100	select ARCH_INLINE_SPIN_LOCK_IRQSAVE
101	select ARCH_INLINE_SPIN_TRYLOCK
102	select ARCH_INLINE_SPIN_TRYLOCK_BH
103	select ARCH_INLINE_SPIN_UNLOCK
104	select ARCH_INLINE_SPIN_UNLOCK_BH
105	select ARCH_INLINE_SPIN_UNLOCK_IRQ
106	select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE
107	select ARCH_INLINE_WRITE_LOCK
108	select ARCH_INLINE_WRITE_LOCK_BH
109	select ARCH_INLINE_WRITE_LOCK_IRQ
110	select ARCH_INLINE_WRITE_LOCK_IRQSAVE
111	select ARCH_INLINE_WRITE_TRYLOCK
112	select ARCH_INLINE_WRITE_UNLOCK
113	select ARCH_INLINE_WRITE_UNLOCK_BH
114	select ARCH_INLINE_WRITE_UNLOCK_IRQ
115	select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
116	select ARCH_STACKWALK
117	select ARCH_SUPPORTS_ATOMIC_RMW
118	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
119	select ARCH_SUPPORTS_HUGETLBFS
120	select ARCH_SUPPORTS_NUMA_BALANCING
121	select ARCH_SUPPORTS_PER_VMA_LOCK
122	select ARCH_USE_BUILTIN_BSWAP
123	select ARCH_USE_CMPXCHG_LOCKREF
124	select ARCH_USE_SYM_ANNOTATIONS
125	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
126	select ARCH_WANTS_NO_INSTR
127	select ARCH_WANT_DEFAULT_BPF_JIT
128	select ARCH_WANT_IPC_PARSE_VERSION
129	select ARCH_WANT_OPTIMIZE_VMEMMAP
130	select BUILDTIME_TABLE_SORT
131	select CLONE_BACKWARDS2
132	select DMA_OPS if PCI
133	select DYNAMIC_FTRACE if FUNCTION_TRACER
134	select FUNCTION_ALIGNMENT_8B if CC_IS_GCC
135	select FUNCTION_ALIGNMENT_16B if !CC_IS_GCC
136	select GENERIC_ALLOCATOR
137	select GENERIC_CPU_AUTOPROBE
138	select GENERIC_CPU_VULNERABILITIES
139	select GENERIC_ENTRY
140	select GENERIC_GETTIMEOFDAY
141	select GENERIC_PTDUMP
142	select GENERIC_SMP_IDLE_THREAD
143	select GENERIC_TIME_VSYSCALL
144	select GENERIC_VDSO_TIME_NS
145	select HAVE_ALIGNED_STRUCT_PAGE if SLUB
146	select HAVE_ARCH_AUDITSYSCALL
147	select HAVE_ARCH_JUMP_LABEL
148	select HAVE_ARCH_JUMP_LABEL_RELATIVE
149	select HAVE_ARCH_KASAN
150	select HAVE_ARCH_KASAN_VMALLOC
151	select HAVE_ARCH_KCSAN
152	select HAVE_ARCH_KFENCE
153	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
154	select HAVE_ARCH_SECCOMP_FILTER
155	select HAVE_ARCH_SOFT_DIRTY
156	select HAVE_ARCH_STACKLEAK
157	select HAVE_ARCH_TRACEHOOK
158	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
159	select HAVE_ARCH_VMAP_STACK
160	select HAVE_ASM_MODVERSIONS
161	select HAVE_CMPXCHG_DOUBLE
162	select HAVE_CMPXCHG_LOCAL
163	select HAVE_DEBUG_KMEMLEAK
164	select HAVE_DMA_CONTIGUOUS
165	select HAVE_DYNAMIC_FTRACE
166	select HAVE_DYNAMIC_FTRACE_WITH_ARGS
167	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
168	select HAVE_DYNAMIC_FTRACE_WITH_REGS
169	select HAVE_EBPF_JIT if HAVE_MARCH_Z196_FEATURES
170	select HAVE_EFFICIENT_UNALIGNED_ACCESS
171	select HAVE_FAST_GUP
172	select HAVE_FENTRY
173	select HAVE_FTRACE_MCOUNT_RECORD
174	select HAVE_FUNCTION_ARG_ACCESS_API
175	select HAVE_FUNCTION_ERROR_INJECTION
176	select HAVE_FUNCTION_GRAPH_TRACER
177	select HAVE_FUNCTION_TRACER
178	select HAVE_GCC_PLUGINS
179	select HAVE_GENERIC_VDSO
180	select HAVE_IOREMAP_PROT if PCI
181	select HAVE_KERNEL_BZIP2
182	select HAVE_KERNEL_GZIP
183	select HAVE_KERNEL_LZ4
184	select HAVE_KERNEL_LZMA
185	select HAVE_KERNEL_LZO
186	select HAVE_KERNEL_UNCOMPRESSED
187	select HAVE_KERNEL_XZ
188	select HAVE_KERNEL_ZSTD
189	select HAVE_KPROBES
190	select HAVE_KPROBES_ON_FTRACE
191	select HAVE_KRETPROBES
192	select HAVE_KVM
193	select HAVE_LIVEPATCH
194	select HAVE_MEMBLOCK_PHYS_MAP
195	select HAVE_MOD_ARCH_SPECIFIC
196	select HAVE_NMI
197	select HAVE_NOP_MCOUNT
198	select HAVE_PCI
199	select HAVE_PERF_EVENTS
200	select HAVE_PERF_REGS
201	select HAVE_PERF_USER_STACK_DUMP
202	select HAVE_REGS_AND_STACK_ACCESS_API
203	select HAVE_RELIABLE_STACKTRACE
204	select HAVE_RETHOOK
205	select HAVE_RSEQ
206	select HAVE_SAMPLE_FTRACE_DIRECT
207	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI
208	select HAVE_SETUP_PER_CPU_AREA
209	select HAVE_SOFTIRQ_ON_OWN_STACK
210	select HAVE_SYSCALL_TRACEPOINTS
211	select HAVE_VIRT_CPU_ACCOUNTING
212	select HAVE_VIRT_CPU_ACCOUNTING_IDLE
213	select IOMMU_HELPER		if PCI
214	select IOMMU_SUPPORT		if PCI
215	select MMU_GATHER_MERGE_VMAS
216	select MMU_GATHER_NO_GATHER
217	select MMU_GATHER_RCU_TABLE_FREE
218	select MODULES_USE_ELF_RELA
219	select NEED_DMA_MAP_STATE	if PCI
220	select NEED_PER_CPU_EMBED_FIRST_CHUNK
221	select NEED_SG_DMA_LENGTH	if PCI
222	select OLD_SIGACTION
223	select OLD_SIGSUSPEND3
224	select PCI_DOMAINS		if PCI
225	select PCI_MSI			if PCI
226	select PCI_MSI_ARCH_FALLBACKS	if PCI_MSI
227	select SPARSE_IRQ
228	select SWIOTLB
229	select SYSCTL_EXCEPTION_TRACE
230	select THREAD_INFO_IN_TASK
231	select TRACE_IRQFLAGS_SUPPORT
232	select TTY
233	select VIRT_CPU_ACCOUNTING
234	select ZONE_DMA
235	# Note: keep the above list sorted alphabetically
236
237config SCHED_OMIT_FRAME_POINTER
238	def_bool y
239
240config PGTABLE_LEVELS
241	int
242	default 5
243
244source "kernel/livepatch/Kconfig"
245
246menu "Processor type and features"
247
248config HAVE_MARCH_Z10_FEATURES
249	def_bool n
250
251config HAVE_MARCH_Z196_FEATURES
252	def_bool n
253	select HAVE_MARCH_Z10_FEATURES
254
255config HAVE_MARCH_ZEC12_FEATURES
256	def_bool n
257	select HAVE_MARCH_Z196_FEATURES
258
259config HAVE_MARCH_Z13_FEATURES
260	def_bool n
261	select HAVE_MARCH_ZEC12_FEATURES
262
263config HAVE_MARCH_Z14_FEATURES
264	def_bool n
265	select HAVE_MARCH_Z13_FEATURES
266
267config HAVE_MARCH_Z15_FEATURES
268	def_bool n
269	select HAVE_MARCH_Z14_FEATURES
270
271config HAVE_MARCH_Z16_FEATURES
272	def_bool n
273	select HAVE_MARCH_Z15_FEATURES
274
275choice
276	prompt "Processor type"
277	default MARCH_Z196
278
279config MARCH_Z10
280	bool "IBM System z10"
281	select HAVE_MARCH_Z10_FEATURES
282	depends on $(cc-option,-march=z10)
283	help
284	  Select this to enable optimizations for IBM System z10 (2097 and 2098
285	  series). This is the oldest machine generation currently supported.
286
287config MARCH_Z196
288	bool "IBM zEnterprise 114 and 196"
289	select HAVE_MARCH_Z196_FEATURES
290	depends on $(cc-option,-march=z196)
291	help
292	  Select this to enable optimizations for IBM zEnterprise 114 and 196
293	  (2818 and 2817 series). The kernel will be slightly faster but will
294	  not work on older machines.
295
296config MARCH_ZEC12
297	bool "IBM zBC12 and zEC12"
298	select HAVE_MARCH_ZEC12_FEATURES
299	depends on $(cc-option,-march=zEC12)
300	help
301	  Select this to enable optimizations for IBM zBC12 and zEC12 (2828 and
302	  2827 series). The kernel will be slightly faster but will not work on
303	  older machines.
304
305config MARCH_Z13
306	bool "IBM z13s and z13"
307	select HAVE_MARCH_Z13_FEATURES
308	depends on $(cc-option,-march=z13)
309	help
310	  Select this to enable optimizations for IBM z13s and z13 (2965 and
311	  2964 series). The kernel will be slightly faster but will not work on
312	  older machines.
313
314config MARCH_Z14
315	bool "IBM z14 ZR1 and z14"
316	select HAVE_MARCH_Z14_FEATURES
317	depends on $(cc-option,-march=z14)
318	help
319	  Select this to enable optimizations for IBM z14 ZR1 and z14 (3907
320	  and 3906 series). The kernel will be slightly faster but will not
321	  work on older machines.
322
323config MARCH_Z15
324	bool "IBM z15"
325	select HAVE_MARCH_Z15_FEATURES
326	depends on $(cc-option,-march=z15)
327	help
328	  Select this to enable optimizations for IBM z15 (8562
329	  and 8561 series). The kernel will be slightly faster but will not
330	  work on older machines.
331
332config MARCH_Z16
333	bool "IBM z16"
334	select HAVE_MARCH_Z16_FEATURES
335	depends on $(cc-option,-march=z16)
336	help
337	  Select this to enable optimizations for IBM z16 (3931 and
338	  3932 series).
339
340endchoice
341
342config MARCH_Z10_TUNE
343	def_bool TUNE_Z10 || MARCH_Z10 && TUNE_DEFAULT
344
345config MARCH_Z196_TUNE
346	def_bool TUNE_Z196 || MARCH_Z196 && TUNE_DEFAULT
347
348config MARCH_ZEC12_TUNE
349	def_bool TUNE_ZEC12 || MARCH_ZEC12 && TUNE_DEFAULT
350
351config MARCH_Z13_TUNE
352	def_bool TUNE_Z13 || MARCH_Z13 && TUNE_DEFAULT
353
354config MARCH_Z14_TUNE
355	def_bool TUNE_Z14 || MARCH_Z14 && TUNE_DEFAULT
356
357config MARCH_Z15_TUNE
358	def_bool TUNE_Z15 || MARCH_Z15 && TUNE_DEFAULT
359
360config MARCH_Z16_TUNE
361	def_bool TUNE_Z16 || MARCH_Z16 && TUNE_DEFAULT
362
363choice
364	prompt "Tune code generation"
365	default TUNE_DEFAULT
366	help
367	  Cause the compiler to tune (-mtune) the generated code for a machine.
368	  This will make the code run faster on the selected machine but
369	  somewhat slower on other machines.
370	  This option only changes how the compiler emits instructions, not the
371	  selection of instructions itself, so the resulting kernel will run on
372	  all other machines.
373
374config TUNE_DEFAULT
375	bool "Default"
376	help
377	  Tune the generated code for the target processor for which the kernel
378	  will be compiled.
379
380config TUNE_Z10
381	bool "IBM System z10"
382
383config TUNE_Z196
384	bool "IBM zEnterprise 114 and 196"
385	depends on $(cc-option,-mtune=z196)
386
387config TUNE_ZEC12
388	bool "IBM zBC12 and zEC12"
389	depends on $(cc-option,-mtune=zEC12)
390
391config TUNE_Z13
392	bool "IBM z13s and z13"
393	depends on $(cc-option,-mtune=z13)
394
395config TUNE_Z14
396	bool "IBM z14 ZR1 and z14"
397	depends on $(cc-option,-mtune=z14)
398
399config TUNE_Z15
400	bool "IBM z15"
401	depends on $(cc-option,-mtune=z15)
402
403config TUNE_Z16
404	bool "IBM z16"
405	depends on $(cc-option,-mtune=z16)
406
407endchoice
408
409config 64BIT
410	def_bool y
411
412config COMMAND_LINE_SIZE
413	int "Maximum size of kernel command line"
414	default 4096
415	range 896 1048576
416	help
417	  This allows you to specify the maximum length of the kernel command
418	  line.
419
420config COMPAT
421	def_bool y
422	prompt "Kernel support for 31 bit emulation"
423	select ARCH_WANT_OLD_COMPAT_IPC
424	select COMPAT_OLD_SIGACTION
425	select HAVE_UID16
426	depends on MULTIUSER
427	depends on !CC_IS_CLANG
428	help
429	  Select this option if you want to enable your system kernel to
430	  handle system-calls from ELF binaries for 31 bit ESA.  This option
431	  (and some other stuff like libraries and such) is needed for
432	  executing 31 bit applications.  It is safe to say "Y".
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
452config NUMA
453	bool "NUMA support"
454	depends on SCHED_TOPOLOGY
455	default n
456	help
457	  Enable NUMA support
458
459	  This option adds NUMA support to the kernel.
460
461config NODES_SHIFT
462	int
463	depends on NUMA
464	default "1"
465
466config SCHED_SMT
467	def_bool n
468
469config SCHED_MC
470	def_bool n
471
472config SCHED_BOOK
473	def_bool n
474
475config SCHED_DRAWER
476	def_bool n
477
478config SCHED_TOPOLOGY
479	def_bool y
480	prompt "Topology scheduler support"
481	select SCHED_SMT
482	select SCHED_MC
483	select SCHED_BOOK
484	select SCHED_DRAWER
485	help
486	  Topology scheduler support improves the CPU scheduler's decision
487	  making when dealing with machines that have multi-threading,
488	  multiple cores or multiple books.
489
490source "kernel/Kconfig.hz"
491
492config KEXEC
493	def_bool y
494	select KEXEC_CORE
495
496config KEXEC_FILE
497	bool "kexec file based system call"
498	select KEXEC_CORE
499	depends on CRYPTO
500	depends on CRYPTO_SHA256
501	depends on CRYPTO_SHA256_S390
502	help
503	  Enable the kexec file based system call. In contrast to the normal
504	  kexec system call this system call takes file descriptors for the
505	  kernel and initramfs as arguments.
506
507config ARCH_HAS_KEXEC_PURGATORY
508	def_bool y
509	depends on KEXEC_FILE
510
511config KEXEC_SIG
512	bool "Verify kernel signature during kexec_file_load() syscall"
513	depends on KEXEC_FILE && MODULE_SIG_FORMAT
514	help
515	  This option makes kernel signature verification mandatory for
516	  the kexec_file_load() syscall.
517
518	  In addition to that option, you need to enable signature
519	  verification for the corresponding kernel image type being
520	  loaded in order for this to work.
521
522config KERNEL_NOBP
523	def_bool n
524	prompt "Enable modified branch prediction for the kernel by default"
525	help
526	  If this option is selected the kernel will switch to a modified
527	  branch prediction mode if the firmware interface is available.
528	  The modified branch prediction mode improves the behaviour in
529	  regard to speculative execution.
530
531	  With the option enabled the kernel parameter "nobp=0" or "nospec"
532	  can be used to run the kernel in the normal branch prediction mode.
533
534	  With the option disabled the modified branch prediction mode is
535	  enabled with the "nobp=1" kernel parameter.
536
537	  If unsure, say N.
538
539config EXPOLINE
540	def_bool n
541	depends on $(cc-option,-mindirect-branch=thunk)
542	prompt "Avoid speculative indirect branches in the kernel"
543	help
544	  Compile the kernel with the expoline compiler options to guard
545	  against kernel-to-user data leaks by avoiding speculative indirect
546	  branches.
547	  Requires a compiler with -mindirect-branch=thunk support for full
548	  protection. The kernel may run slower.
549
550	  If unsure, say N.
551
552config EXPOLINE_EXTERN
553	def_bool n
554	depends on EXPOLINE
555	depends on CC_IS_GCC && GCC_VERSION >= 110200
556	depends on $(success,$(srctree)/arch/s390/tools/gcc-thunk-extern.sh $(CC))
557	prompt "Generate expolines as extern functions."
558	help
559	  This option is required for some tooling like kpatch. The kernel is
560	  compiled with -mindirect-branch=thunk-extern and requires a newer
561	  compiler.
562
563	  If unsure, say N.
564
565choice
566	prompt "Expoline default"
567	depends on EXPOLINE
568	default EXPOLINE_FULL
569
570config EXPOLINE_OFF
571	bool "spectre_v2=off"
572
573config EXPOLINE_AUTO
574	bool "spectre_v2=auto"
575
576config EXPOLINE_FULL
577	bool "spectre_v2=on"
578
579endchoice
580
581config RELOCATABLE
582	def_bool y
583	help
584	  This builds a kernel image that retains relocation information
585	  so it can be loaded at an arbitrary address.
586	  The kernel is linked as a position-independent executable (PIE)
587	  and contains dynamic relocations which are processed early in the
588	  bootup process.
589	  The relocations make the kernel image about 15% larger (compressed
590	  10%), but are discarded at runtime.
591	  Note: this option exists only for documentation purposes, please do
592	  not remove it.
593
594config RANDOMIZE_BASE
595	bool "Randomize the address of the kernel image (KASLR)"
596	default y
597	help
598	  In support of Kernel Address Space Layout Randomization (KASLR),
599	  this randomizes the address at which the kernel image is loaded,
600	  as a security feature that deters exploit attempts relying on
601	  knowledge of the location of kernel internals.
602
603endmenu
604
605menu "Memory setup"
606
607config ARCH_SPARSEMEM_ENABLE
608	def_bool y
609	select SPARSEMEM_VMEMMAP_ENABLE
610	select SPARSEMEM_VMEMMAP
611
612config ARCH_SPARSEMEM_DEFAULT
613	def_bool y
614
615config MAX_PHYSMEM_BITS
616	int "Maximum size of supported physical memory in bits (42-53)"
617	range 42 53
618	default "46"
619	help
620	  This option specifies the maximum supported size of physical memory
621	  in bits. Supported is any size between 2^42 (4TB) and 2^53 (8PB).
622	  Increasing the number of bits also increases the kernel image size.
623	  By default 46 bits (64TB) are supported.
624
625config CHECK_STACK
626	def_bool y
627	depends on !VMAP_STACK
628	prompt "Detect kernel stack overflow"
629	help
630	  This option enables the compiler option -mstack-guard and
631	  -mstack-size if they are available. If the compiler supports them
632	  it will emit additional code to each function prolog to trigger
633	  an illegal operation if the kernel stack is about to overflow.
634
635	  Say N if you are unsure.
636
637config STACK_GUARD
638	int "Size of the guard area (128-1024)"
639	range 128 1024
640	depends on CHECK_STACK
641	default "256"
642	help
643	  This allows you to specify the size of the guard area at the lower
644	  end of the kernel stack. If the kernel stack points into the guard
645	  area on function entry an illegal operation is triggered. The size
646	  needs to be a power of 2. Please keep in mind that the size of an
647	  interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
648	  The minimum size for the stack guard should be 256 for 31 bit and
649	  512 for 64 bit.
650
651endmenu
652
653menu "I/O subsystem"
654
655config QDIO
656	def_tristate y
657	prompt "QDIO support"
658	help
659	  This driver provides the Queued Direct I/O base support for
660	  IBM System z.
661
662	  To compile this driver as a module, choose M here: the
663	  module will be called qdio.
664
665	  If unsure, say Y.
666
667if PCI
668
669config PCI_NR_FUNCTIONS
670	int "Maximum number of PCI functions (1-4096)"
671	range 1 4096
672	default "512"
673	help
674	  This allows you to specify the maximum number of PCI functions which
675	  this kernel will support.
676
677endif # PCI
678
679config HAS_IOMEM
680	def_bool PCI
681
682config CHSC_SCH
683	def_tristate m
684	prompt "Support for CHSC subchannels"
685	help
686	  This driver allows usage of CHSC subchannels. A CHSC subchannel
687	  is usually present on LPAR only.
688	  The driver creates a device /dev/chsc, which may be used to
689	  obtain I/O configuration information about the machine and
690	  to issue asynchronous chsc commands (DANGEROUS).
691	  You will usually only want to use this interface on a special
692	  LPAR designated for system management.
693
694	  To compile this driver as a module, choose M here: the
695	  module will be called chsc_sch.
696
697	  If unsure, say N.
698
699config SCM_BUS
700	def_bool y
701	prompt "SCM bus driver"
702	help
703	  Bus driver for Storage Class Memory.
704
705config EADM_SCH
706	def_tristate m
707	prompt "Support for EADM subchannels"
708	depends on SCM_BUS
709	help
710	  This driver allows usage of EADM subchannels. EADM subchannels act
711	  as a communication vehicle for SCM increments.
712
713	  To compile this driver as a module, choose M here: the
714	  module will be called eadm_sch.
715
716config VFIO_CCW
717	def_tristate n
718	prompt "Support for VFIO-CCW subchannels"
719	depends on S390_CCW_IOMMU
720	depends on VFIO
721	select VFIO_MDEV
722	help
723	  This driver allows usage of I/O subchannels via VFIO-CCW.
724
725	  To compile this driver as a module, choose M here: the
726	  module will be called vfio_ccw.
727
728config VFIO_AP
729	def_tristate n
730	prompt "VFIO support for AP devices"
731	depends on S390_AP_IOMMU && KVM
732	depends on VFIO
733	depends on ZCRYPT
734	select VFIO_MDEV
735	help
736	  This driver grants access to Adjunct Processor (AP) devices
737	  via the VFIO mediated device interface.
738
739	  To compile this driver as a module, choose M here: the module
740	  will be called vfio_ap.
741
742endmenu
743
744menu "Dump support"
745
746config CRASH_DUMP
747	bool "kernel crash dumps"
748	select KEXEC
749	help
750	  Generate crash dump after being started by kexec.
751	  Crash dump kernels are loaded in the main kernel with kexec-tools
752	  into a specially reserved region and then later executed after
753	  a crash by kdump/kexec.
754	  Refer to <file:Documentation/s390/zfcpdump.rst> for more details on this.
755	  This option also enables s390 zfcpdump.
756	  See also <file:Documentation/s390/zfcpdump.rst>
757
758endmenu
759
760config CCW
761	def_bool y
762
763config HAVE_PNETID
764	tristate
765	default (SMC || CCWGROUP)
766
767menu "Virtualization"
768
769config PROTECTED_VIRTUALIZATION_GUEST
770	def_bool n
771	prompt "Protected virtualization guest support"
772	help
773	  Select this option, if you want to be able to run this
774	  kernel as a protected virtualization KVM guest.
775	  Protected virtualization capable machines have a mini hypervisor
776	  located at machine level (an ultravisor). With help of the
777	  Ultravisor, KVM will be able to run "protected" VMs, special
778	  VMs whose memory and management data are unavailable to KVM.
779
780config PFAULT
781	def_bool y
782	prompt "Pseudo page fault support"
783	help
784	  Select this option, if you want to use PFAULT pseudo page fault
785	  handling under VM. If running native or in LPAR, this option
786	  has no effect. If your VM does not support PFAULT, PAGEEX
787	  pseudo page fault handling will be used.
788	  Note that VM 4.2 supports PFAULT but has a bug in its
789	  implementation that causes some problems.
790	  Everybody who wants to run Linux under VM != VM4.2 should select
791	  this option.
792
793config CMM
794	def_tristate n
795	prompt "Cooperative memory management"
796	help
797	  Select this option, if you want to enable the kernel interface
798	  to reduce the memory size of the system. This is accomplished
799	  by allocating pages of memory and put them "on hold". This only
800	  makes sense for a system running under VM where the unused pages
801	  will be reused by VM for other guest systems. The interface
802	  allows an external monitor to balance memory of many systems.
803	  Everybody who wants to run Linux under VM should select this
804	  option.
805
806config CMM_IUCV
807	def_bool y
808	prompt "IUCV special message interface to cooperative memory management"
809	depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
810	help
811	  Select this option to enable the special message interface to
812	  the cooperative memory management.
813
814config APPLDATA_BASE
815	def_bool n
816	prompt "Linux - VM Monitor Stream, base infrastructure"
817	depends on PROC_SYSCTL
818	help
819	  This provides a kernel interface for creating and updating z/VM APPLDATA
820	  monitor records. The monitor records are updated at certain time
821	  intervals, once the timer is started.
822	  Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
823	  i.e. enables or disables monitoring on the Linux side.
824	  A custom interval value (in seconds) can be written to
825	  /proc/appldata/interval.
826
827	  Defaults are 60 seconds interval and timer off.
828	  The /proc entries can also be read from, showing the current settings.
829
830config APPLDATA_MEM
831	def_tristate m
832	prompt "Monitor memory management statistics"
833	depends on APPLDATA_BASE && VM_EVENT_COUNTERS
834	help
835	  This provides memory management related data to the Linux - VM Monitor
836	  Stream, like paging/swapping rate, memory utilisation, etc.
837	  Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
838	  APPLDATA monitor record, i.e. enables or disables monitoring this record
839	  on the z/VM side.
840
841	  Default is disabled.
842	  The /proc entry can also be read from, showing the current settings.
843
844	  This can also be compiled as a module, which will be called
845	  appldata_mem.o.
846
847config APPLDATA_OS
848	def_tristate m
849	prompt "Monitor OS statistics"
850	depends on APPLDATA_BASE
851	help
852	  This provides OS related data to the Linux - VM Monitor Stream, like
853	  CPU utilisation, etc.
854	  Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
855	  APPLDATA monitor record, i.e. enables or disables monitoring this record
856	  on the z/VM side.
857
858	  Default is disabled.
859	  This can also be compiled as a module, which will be called
860	  appldata_os.o.
861
862config APPLDATA_NET_SUM
863	def_tristate m
864	prompt "Monitor overall network statistics"
865	depends on APPLDATA_BASE && NET
866	help
867	  This provides network related data to the Linux - VM Monitor Stream,
868	  currently there is only a total sum of network I/O statistics, no
869	  per-interface data.
870	  Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
871	  APPLDATA monitor record, i.e. enables or disables monitoring this record
872	  on the z/VM side.
873
874	  Default is disabled.
875	  This can also be compiled as a module, which will be called
876	  appldata_net_sum.o.
877
878config S390_HYPFS_FS
879	def_bool y
880	prompt "s390 hypervisor file system support"
881	select SYS_HYPERVISOR
882	help
883	  This is a virtual file system intended to provide accounting
884	  information in an s390 hypervisor environment.
885
886source "arch/s390/kvm/Kconfig"
887
888config S390_GUEST
889	def_bool y
890	prompt "s390 support for virtio devices"
891	select TTY
892	select VIRTUALIZATION
893	select VIRTIO
894	help
895	  Enabling this option adds support for virtio based paravirtual device
896	  drivers on s390.
897
898	  Select this option if you want to run the kernel as a guest under
899	  the KVM hypervisor.
900
901endmenu
902
903config S390_MODULES_SANITY_TEST_HELPERS
904	def_bool n
905
906menu "Selftests"
907
908config S390_UNWIND_SELFTEST
909	def_tristate n
910	depends on KUNIT
911	default KUNIT_ALL_TESTS
912	prompt "Test unwind functions"
913	help
914	  This option enables s390 specific stack unwinder testing kernel
915	  module. This option is not useful for distributions or general
916	  kernels, but only for kernel developers working on architecture code.
917
918	  Say N if you are unsure.
919
920config S390_KPROBES_SANITY_TEST
921	def_tristate n
922	prompt "Enable s390 specific kprobes tests"
923	depends on KPROBES
924	depends on KUNIT
925	help
926	  This option enables an s390 specific kprobes test module. This option
927	  is not useful for distributions or general kernels, but only for kernel
928	  developers working on architecture code.
929
930	  Say N if you are unsure.
931
932config S390_MODULES_SANITY_TEST
933	def_tristate n
934	depends on KUNIT
935	default KUNIT_ALL_TESTS
936	prompt "Enable s390 specific modules tests"
937	select S390_MODULES_SANITY_TEST_HELPERS
938	help
939	  This option enables an s390 specific modules test. This option is
940	  not useful for distributions or general kernels, but only for
941	  kernel developers working on architecture code.
942
943	  Say N if you are unsure.
944endmenu
945