xref: /openbmc/linux/arch/s390/Kconfig (revision 59e09100)
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_INT128 if CC_HAS_INT128 && CC_IS_CLANG
121	select ARCH_SUPPORTS_NUMA_BALANCING
122	select ARCH_SUPPORTS_PER_VMA_LOCK
123	select ARCH_USE_BUILTIN_BSWAP
124	select ARCH_USE_CMPXCHG_LOCKREF
125	select ARCH_USE_SYM_ANNOTATIONS
126	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
127	select ARCH_WANTS_NO_INSTR
128	select ARCH_WANT_DEFAULT_BPF_JIT
129	select ARCH_WANT_IPC_PARSE_VERSION
130	select ARCH_WANT_OPTIMIZE_VMEMMAP
131	select BUILDTIME_TABLE_SORT
132	select CLONE_BACKWARDS2
133	select DMA_OPS if PCI
134	select DYNAMIC_FTRACE if FUNCTION_TRACER
135	select FUNCTION_ALIGNMENT_8B if CC_IS_GCC
136	select FUNCTION_ALIGNMENT_16B if !CC_IS_GCC
137	select GENERIC_ALLOCATOR
138	select GENERIC_CPU_AUTOPROBE
139	select GENERIC_CPU_VULNERABILITIES
140	select GENERIC_ENTRY
141	select GENERIC_GETTIMEOFDAY
142	select GENERIC_PTDUMP
143	select GENERIC_SMP_IDLE_THREAD
144	select GENERIC_TIME_VSYSCALL
145	select GENERIC_VDSO_TIME_NS
146	select HAVE_ALIGNED_STRUCT_PAGE if SLUB
147	select HAVE_ARCH_AUDITSYSCALL
148	select HAVE_ARCH_JUMP_LABEL
149	select HAVE_ARCH_JUMP_LABEL_RELATIVE
150	select HAVE_ARCH_KASAN
151	select HAVE_ARCH_KASAN_VMALLOC
152	select HAVE_ARCH_KCSAN
153	select HAVE_ARCH_KFENCE
154	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
155	select HAVE_ARCH_SECCOMP_FILTER
156	select HAVE_ARCH_SOFT_DIRTY
157	select HAVE_ARCH_STACKLEAK
158	select HAVE_ARCH_TRACEHOOK
159	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
160	select HAVE_ARCH_VMAP_STACK
161	select HAVE_ASM_MODVERSIONS
162	select HAVE_CMPXCHG_DOUBLE
163	select HAVE_CMPXCHG_LOCAL
164	select HAVE_DEBUG_KMEMLEAK
165	select HAVE_DMA_CONTIGUOUS
166	select HAVE_DYNAMIC_FTRACE
167	select HAVE_DYNAMIC_FTRACE_WITH_ARGS
168	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
169	select HAVE_DYNAMIC_FTRACE_WITH_REGS
170	select HAVE_EBPF_JIT if HAVE_MARCH_Z196_FEATURES
171	select HAVE_EFFICIENT_UNALIGNED_ACCESS
172	select HAVE_FAST_GUP
173	select HAVE_FENTRY
174	select HAVE_FTRACE_MCOUNT_RECORD
175	select HAVE_FUNCTION_ARG_ACCESS_API
176	select HAVE_FUNCTION_ERROR_INJECTION
177	select HAVE_FUNCTION_GRAPH_TRACER
178	select HAVE_FUNCTION_TRACER
179	select HAVE_GCC_PLUGINS
180	select HAVE_GENERIC_VDSO
181	select HAVE_IOREMAP_PROT if PCI
182	select HAVE_KERNEL_BZIP2
183	select HAVE_KERNEL_GZIP
184	select HAVE_KERNEL_LZ4
185	select HAVE_KERNEL_LZMA
186	select HAVE_KERNEL_LZO
187	select HAVE_KERNEL_UNCOMPRESSED
188	select HAVE_KERNEL_XZ
189	select HAVE_KERNEL_ZSTD
190	select HAVE_KPROBES
191	select HAVE_KPROBES_ON_FTRACE
192	select HAVE_KRETPROBES
193	select HAVE_KVM
194	select HAVE_LIVEPATCH
195	select HAVE_MEMBLOCK_PHYS_MAP
196	select HAVE_MOD_ARCH_SPECIFIC
197	select HAVE_NMI
198	select HAVE_NOP_MCOUNT
199	select HAVE_PCI
200	select HAVE_PERF_EVENTS
201	select HAVE_PERF_REGS
202	select HAVE_PERF_USER_STACK_DUMP
203	select HAVE_REGS_AND_STACK_ACCESS_API
204	select HAVE_RELIABLE_STACKTRACE
205	select HAVE_RETHOOK
206	select HAVE_RSEQ
207	select HAVE_SAMPLE_FTRACE_DIRECT
208	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI
209	select HAVE_SETUP_PER_CPU_AREA
210	select HAVE_SOFTIRQ_ON_OWN_STACK
211	select HAVE_SYSCALL_TRACEPOINTS
212	select HAVE_VIRT_CPU_ACCOUNTING
213	select HAVE_VIRT_CPU_ACCOUNTING_IDLE
214	select IOMMU_HELPER		if PCI
215	select IOMMU_SUPPORT		if PCI
216	select MMU_GATHER_MERGE_VMAS
217	select MMU_GATHER_NO_GATHER
218	select MMU_GATHER_RCU_TABLE_FREE
219	select MODULES_USE_ELF_RELA
220	select NEED_DMA_MAP_STATE	if PCI
221	select NEED_PER_CPU_EMBED_FIRST_CHUNK
222	select NEED_SG_DMA_LENGTH	if PCI
223	select OLD_SIGACTION
224	select OLD_SIGSUSPEND3
225	select PCI_DOMAINS		if PCI
226	select PCI_MSI			if PCI
227	select PCI_MSI_ARCH_FALLBACKS	if PCI_MSI
228	select SPARSE_IRQ
229	select SWIOTLB
230	select SYSCTL_EXCEPTION_TRACE
231	select THREAD_INFO_IN_TASK
232	select TRACE_IRQFLAGS_SUPPORT
233	select TTY
234	select VIRT_CPU_ACCOUNTING
235	select ZONE_DMA
236	# Note: keep the above list sorted alphabetically
237
238config SCHED_OMIT_FRAME_POINTER
239	def_bool y
240
241config PGTABLE_LEVELS
242	int
243	default 5
244
245source "kernel/livepatch/Kconfig"
246
247menu "Processor type and features"
248
249config HAVE_MARCH_Z10_FEATURES
250	def_bool n
251
252config HAVE_MARCH_Z196_FEATURES
253	def_bool n
254	select HAVE_MARCH_Z10_FEATURES
255
256config HAVE_MARCH_ZEC12_FEATURES
257	def_bool n
258	select HAVE_MARCH_Z196_FEATURES
259
260config HAVE_MARCH_Z13_FEATURES
261	def_bool n
262	select HAVE_MARCH_ZEC12_FEATURES
263
264config HAVE_MARCH_Z14_FEATURES
265	def_bool n
266	select HAVE_MARCH_Z13_FEATURES
267
268config HAVE_MARCH_Z15_FEATURES
269	def_bool n
270	select HAVE_MARCH_Z14_FEATURES
271
272config HAVE_MARCH_Z16_FEATURES
273	def_bool n
274	select HAVE_MARCH_Z15_FEATURES
275
276choice
277	prompt "Processor type"
278	default MARCH_Z196
279
280config MARCH_Z10
281	bool "IBM System z10"
282	select HAVE_MARCH_Z10_FEATURES
283	depends on $(cc-option,-march=z10)
284	help
285	  Select this to enable optimizations for IBM System z10 (2097 and 2098
286	  series). This is the oldest machine generation currently supported.
287
288config MARCH_Z196
289	bool "IBM zEnterprise 114 and 196"
290	select HAVE_MARCH_Z196_FEATURES
291	depends on $(cc-option,-march=z196)
292	help
293	  Select this to enable optimizations for IBM zEnterprise 114 and 196
294	  (2818 and 2817 series). The kernel will be slightly faster but will
295	  not work on older machines.
296
297config MARCH_ZEC12
298	bool "IBM zBC12 and zEC12"
299	select HAVE_MARCH_ZEC12_FEATURES
300	depends on $(cc-option,-march=zEC12)
301	help
302	  Select this to enable optimizations for IBM zBC12 and zEC12 (2828 and
303	  2827 series). The kernel will be slightly faster but will not work on
304	  older machines.
305
306config MARCH_Z13
307	bool "IBM z13s and z13"
308	select HAVE_MARCH_Z13_FEATURES
309	depends on $(cc-option,-march=z13)
310	help
311	  Select this to enable optimizations for IBM z13s and z13 (2965 and
312	  2964 series). The kernel will be slightly faster but will not work on
313	  older machines.
314
315config MARCH_Z14
316	bool "IBM z14 ZR1 and z14"
317	select HAVE_MARCH_Z14_FEATURES
318	depends on $(cc-option,-march=z14)
319	help
320	  Select this to enable optimizations for IBM z14 ZR1 and z14 (3907
321	  and 3906 series). The kernel will be slightly faster but will not
322	  work on older machines.
323
324config MARCH_Z15
325	bool "IBM z15"
326	select HAVE_MARCH_Z15_FEATURES
327	depends on $(cc-option,-march=z15)
328	help
329	  Select this to enable optimizations for IBM z15 (8562
330	  and 8561 series). The kernel will be slightly faster but will not
331	  work on older machines.
332
333config MARCH_Z16
334	bool "IBM z16"
335	select HAVE_MARCH_Z16_FEATURES
336	depends on $(cc-option,-march=z16)
337	help
338	  Select this to enable optimizations for IBM z16 (3931 and
339	  3932 series).
340
341endchoice
342
343config MARCH_Z10_TUNE
344	def_bool TUNE_Z10 || MARCH_Z10 && TUNE_DEFAULT
345
346config MARCH_Z196_TUNE
347	def_bool TUNE_Z196 || MARCH_Z196 && TUNE_DEFAULT
348
349config MARCH_ZEC12_TUNE
350	def_bool TUNE_ZEC12 || MARCH_ZEC12 && TUNE_DEFAULT
351
352config MARCH_Z13_TUNE
353	def_bool TUNE_Z13 || MARCH_Z13 && TUNE_DEFAULT
354
355config MARCH_Z14_TUNE
356	def_bool TUNE_Z14 || MARCH_Z14 && TUNE_DEFAULT
357
358config MARCH_Z15_TUNE
359	def_bool TUNE_Z15 || MARCH_Z15 && TUNE_DEFAULT
360
361config MARCH_Z16_TUNE
362	def_bool TUNE_Z16 || MARCH_Z16 && TUNE_DEFAULT
363
364choice
365	prompt "Tune code generation"
366	default TUNE_DEFAULT
367	help
368	  Cause the compiler to tune (-mtune) the generated code for a machine.
369	  This will make the code run faster on the selected machine but
370	  somewhat slower on other machines.
371	  This option only changes how the compiler emits instructions, not the
372	  selection of instructions itself, so the resulting kernel will run on
373	  all other machines.
374
375config TUNE_DEFAULT
376	bool "Default"
377	help
378	  Tune the generated code for the target processor for which the kernel
379	  will be compiled.
380
381config TUNE_Z10
382	bool "IBM System z10"
383
384config TUNE_Z196
385	bool "IBM zEnterprise 114 and 196"
386	depends on $(cc-option,-mtune=z196)
387
388config TUNE_ZEC12
389	bool "IBM zBC12 and zEC12"
390	depends on $(cc-option,-mtune=zEC12)
391
392config TUNE_Z13
393	bool "IBM z13s and z13"
394	depends on $(cc-option,-mtune=z13)
395
396config TUNE_Z14
397	bool "IBM z14 ZR1 and z14"
398	depends on $(cc-option,-mtune=z14)
399
400config TUNE_Z15
401	bool "IBM z15"
402	depends on $(cc-option,-mtune=z15)
403
404config TUNE_Z16
405	bool "IBM z16"
406	depends on $(cc-option,-mtune=z16)
407
408endchoice
409
410config 64BIT
411	def_bool y
412
413config COMMAND_LINE_SIZE
414	int "Maximum size of kernel command line"
415	default 4096
416	range 896 1048576
417	help
418	  This allows you to specify the maximum length of the kernel command
419	  line.
420
421config COMPAT
422	def_bool y
423	prompt "Kernel support for 31 bit emulation"
424	select ARCH_WANT_OLD_COMPAT_IPC
425	select COMPAT_OLD_SIGACTION
426	select HAVE_UID16
427	depends on MULTIUSER
428	depends on !CC_IS_CLANG
429	help
430	  Select this option if you want to enable your system kernel to
431	  handle system-calls from ELF binaries for 31 bit ESA.  This option
432	  (and some other stuff like libraries and such) is needed for
433	  executing 31 bit applications.  It is safe to say "Y".
434
435config SMP
436	def_bool y
437
438config NR_CPUS
439	int "Maximum number of CPUs (2-512)"
440	range 2 512
441	default "64"
442	help
443	  This allows you to specify the maximum number of CPUs which this
444	  kernel will support. The maximum supported value is 512 and the
445	  minimum value which makes sense is 2.
446
447	  This is purely to save memory - each supported CPU adds
448	  approximately sixteen kilobytes to the kernel image.
449
450config HOTPLUG_CPU
451	def_bool y
452
453config NUMA
454	bool "NUMA support"
455	depends on SCHED_TOPOLOGY
456	default n
457	help
458	  Enable NUMA support
459
460	  This option adds NUMA support to the kernel.
461
462config NODES_SHIFT
463	int
464	depends on NUMA
465	default "1"
466
467config SCHED_SMT
468	def_bool n
469
470config SCHED_MC
471	def_bool n
472
473config SCHED_TOPOLOGY
474	def_bool y
475	prompt "Topology scheduler support"
476	select SCHED_SMT
477	select SCHED_MC
478	help
479	  Topology scheduler support improves the CPU scheduler's decision
480	  making when dealing with machines that have multi-threading,
481	  multiple cores or multiple books.
482
483source "kernel/Kconfig.hz"
484
485config KEXEC
486	def_bool y
487	select KEXEC_CORE
488
489config KEXEC_FILE
490	bool "kexec file based system call"
491	select KEXEC_CORE
492	depends on CRYPTO
493	depends on CRYPTO_SHA256
494	depends on CRYPTO_SHA256_S390
495	help
496	  Enable the kexec file based system call. In contrast to the normal
497	  kexec system call this system call takes file descriptors for the
498	  kernel and initramfs as arguments.
499
500config ARCH_HAS_KEXEC_PURGATORY
501	def_bool y
502	depends on KEXEC_FILE
503
504config KEXEC_SIG
505	bool "Verify kernel signature during kexec_file_load() syscall"
506	depends on KEXEC_FILE && MODULE_SIG_FORMAT
507	help
508	  This option makes kernel signature verification mandatory for
509	  the kexec_file_load() syscall.
510
511	  In addition to that option, you need to enable signature
512	  verification for the corresponding kernel image type being
513	  loaded in order for this to work.
514
515config KERNEL_NOBP
516	def_bool n
517	prompt "Enable modified branch prediction for the kernel by default"
518	help
519	  If this option is selected the kernel will switch to a modified
520	  branch prediction mode if the firmware interface is available.
521	  The modified branch prediction mode improves the behaviour in
522	  regard to speculative execution.
523
524	  With the option enabled the kernel parameter "nobp=0" or "nospec"
525	  can be used to run the kernel in the normal branch prediction mode.
526
527	  With the option disabled the modified branch prediction mode is
528	  enabled with the "nobp=1" kernel parameter.
529
530	  If unsure, say N.
531
532config EXPOLINE
533	def_bool n
534	depends on $(cc-option,-mindirect-branch=thunk)
535	prompt "Avoid speculative indirect branches in the kernel"
536	help
537	  Compile the kernel with the expoline compiler options to guard
538	  against kernel-to-user data leaks by avoiding speculative indirect
539	  branches.
540	  Requires a compiler with -mindirect-branch=thunk support for full
541	  protection. The kernel may run slower.
542
543	  If unsure, say N.
544
545config EXPOLINE_EXTERN
546	def_bool n
547	depends on EXPOLINE
548	depends on CC_IS_GCC && GCC_VERSION >= 110200
549	depends on $(success,$(srctree)/arch/s390/tools/gcc-thunk-extern.sh $(CC))
550	prompt "Generate expolines as extern functions."
551	help
552	  This option is required for some tooling like kpatch. The kernel is
553	  compiled with -mindirect-branch=thunk-extern and requires a newer
554	  compiler.
555
556	  If unsure, say N.
557
558choice
559	prompt "Expoline default"
560	depends on EXPOLINE
561	default EXPOLINE_FULL
562
563config EXPOLINE_OFF
564	bool "spectre_v2=off"
565
566config EXPOLINE_AUTO
567	bool "spectre_v2=auto"
568
569config EXPOLINE_FULL
570	bool "spectre_v2=on"
571
572endchoice
573
574config RELOCATABLE
575	def_bool y
576	help
577	  This builds a kernel image that retains relocation information
578	  so it can be loaded at an arbitrary address.
579	  The kernel is linked as a position-independent executable (PIE)
580	  and contains dynamic relocations which are processed early in the
581	  bootup process.
582	  The relocations make the kernel image about 15% larger (compressed
583	  10%), but are discarded at runtime.
584	  Note: this option exists only for documentation purposes, please do
585	  not remove it.
586
587config RANDOMIZE_BASE
588	bool "Randomize the address of the kernel image (KASLR)"
589	default y
590	help
591	  In support of Kernel Address Space Layout Randomization (KASLR),
592	  this randomizes the address at which the kernel image is loaded,
593	  as a security feature that deters exploit attempts relying on
594	  knowledge of the location of kernel internals.
595
596endmenu
597
598menu "Memory setup"
599
600config ARCH_SPARSEMEM_ENABLE
601	def_bool y
602	select SPARSEMEM_VMEMMAP_ENABLE
603	select SPARSEMEM_VMEMMAP
604
605config ARCH_SPARSEMEM_DEFAULT
606	def_bool y
607
608config MAX_PHYSMEM_BITS
609	int "Maximum size of supported physical memory in bits (42-53)"
610	range 42 53
611	default "46"
612	help
613	  This option specifies the maximum supported size of physical memory
614	  in bits. Supported is any size between 2^42 (4TB) and 2^53 (8PB).
615	  Increasing the number of bits also increases the kernel image size.
616	  By default 46 bits (64TB) are supported.
617
618config CHECK_STACK
619	def_bool y
620	depends on !VMAP_STACK
621	prompt "Detect kernel stack overflow"
622	help
623	  This option enables the compiler option -mstack-guard and
624	  -mstack-size if they are available. If the compiler supports them
625	  it will emit additional code to each function prolog to trigger
626	  an illegal operation if the kernel stack is about to overflow.
627
628	  Say N if you are unsure.
629
630config STACK_GUARD
631	int "Size of the guard area (128-1024)"
632	range 128 1024
633	depends on CHECK_STACK
634	default "256"
635	help
636	  This allows you to specify the size of the guard area at the lower
637	  end of the kernel stack. If the kernel stack points into the guard
638	  area on function entry an illegal operation is triggered. The size
639	  needs to be a power of 2. Please keep in mind that the size of an
640	  interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
641	  The minimum size for the stack guard should be 256 for 31 bit and
642	  512 for 64 bit.
643
644endmenu
645
646menu "I/O subsystem"
647
648config QDIO
649	def_tristate y
650	prompt "QDIO support"
651	help
652	  This driver provides the Queued Direct I/O base support for
653	  IBM System z.
654
655	  To compile this driver as a module, choose M here: the
656	  module will be called qdio.
657
658	  If unsure, say Y.
659
660if PCI
661
662config PCI_NR_FUNCTIONS
663	int "Maximum number of PCI functions (1-4096)"
664	range 1 4096
665	default "512"
666	help
667	  This allows you to specify the maximum number of PCI functions which
668	  this kernel will support.
669
670endif # PCI
671
672config HAS_IOMEM
673	def_bool PCI
674
675config CHSC_SCH
676	def_tristate m
677	prompt "Support for CHSC subchannels"
678	help
679	  This driver allows usage of CHSC subchannels. A CHSC subchannel
680	  is usually present on LPAR only.
681	  The driver creates a device /dev/chsc, which may be used to
682	  obtain I/O configuration information about the machine and
683	  to issue asynchronous chsc commands (DANGEROUS).
684	  You will usually only want to use this interface on a special
685	  LPAR designated for system management.
686
687	  To compile this driver as a module, choose M here: the
688	  module will be called chsc_sch.
689
690	  If unsure, say N.
691
692config SCM_BUS
693	def_bool y
694	prompt "SCM bus driver"
695	help
696	  Bus driver for Storage Class Memory.
697
698config EADM_SCH
699	def_tristate m
700	prompt "Support for EADM subchannels"
701	depends on SCM_BUS
702	help
703	  This driver allows usage of EADM subchannels. EADM subchannels act
704	  as a communication vehicle for SCM increments.
705
706	  To compile this driver as a module, choose M here: the
707	  module will be called eadm_sch.
708
709config VFIO_CCW
710	def_tristate n
711	prompt "Support for VFIO-CCW subchannels"
712	depends on VFIO
713	select VFIO_MDEV
714	help
715	  This driver allows usage of I/O subchannels via VFIO-CCW.
716
717	  To compile this driver as a module, choose M here: the
718	  module will be called vfio_ccw.
719
720config VFIO_AP
721	def_tristate n
722	prompt "VFIO support for AP devices"
723	depends on KVM
724	depends on VFIO
725	depends on ZCRYPT
726	select VFIO_MDEV
727	help
728	  This driver grants access to Adjunct Processor (AP) devices
729	  via the VFIO mediated device interface.
730
731	  To compile this driver as a module, choose M here: the module
732	  will be called vfio_ap.
733
734endmenu
735
736menu "Dump support"
737
738config CRASH_DUMP
739	bool "kernel crash dumps"
740	select KEXEC
741	help
742	  Generate crash dump after being started by kexec.
743	  Crash dump kernels are loaded in the main kernel with kexec-tools
744	  into a specially reserved region and then later executed after
745	  a crash by kdump/kexec.
746	  Refer to <file:Documentation/s390/zfcpdump.rst> for more details on this.
747	  This option also enables s390 zfcpdump.
748	  See also <file:Documentation/s390/zfcpdump.rst>
749
750endmenu
751
752config CCW
753	def_bool y
754
755config HAVE_PNETID
756	tristate
757	default (SMC || CCWGROUP)
758
759menu "Virtualization"
760
761config PROTECTED_VIRTUALIZATION_GUEST
762	def_bool n
763	prompt "Protected virtualization guest support"
764	help
765	  Select this option, if you want to be able to run this
766	  kernel as a protected virtualization KVM guest.
767	  Protected virtualization capable machines have a mini hypervisor
768	  located at machine level (an ultravisor). With help of the
769	  Ultravisor, KVM will be able to run "protected" VMs, special
770	  VMs whose memory and management data are unavailable to KVM.
771
772config PFAULT
773	def_bool y
774	prompt "Pseudo page fault support"
775	help
776	  Select this option, if you want to use PFAULT pseudo page fault
777	  handling under VM. If running native or in LPAR, this option
778	  has no effect. If your VM does not support PFAULT, PAGEEX
779	  pseudo page fault handling will be used.
780	  Note that VM 4.2 supports PFAULT but has a bug in its
781	  implementation that causes some problems.
782	  Everybody who wants to run Linux under VM != VM4.2 should select
783	  this option.
784
785config CMM
786	def_tristate n
787	prompt "Cooperative memory management"
788	help
789	  Select this option, if you want to enable the kernel interface
790	  to reduce the memory size of the system. This is accomplished
791	  by allocating pages of memory and put them "on hold". This only
792	  makes sense for a system running under VM where the unused pages
793	  will be reused by VM for other guest systems. The interface
794	  allows an external monitor to balance memory of many systems.
795	  Everybody who wants to run Linux under VM should select this
796	  option.
797
798config CMM_IUCV
799	def_bool y
800	prompt "IUCV special message interface to cooperative memory management"
801	depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
802	help
803	  Select this option to enable the special message interface to
804	  the cooperative memory management.
805
806config APPLDATA_BASE
807	def_bool n
808	prompt "Linux - VM Monitor Stream, base infrastructure"
809	depends on PROC_SYSCTL
810	help
811	  This provides a kernel interface for creating and updating z/VM APPLDATA
812	  monitor records. The monitor records are updated at certain time
813	  intervals, once the timer is started.
814	  Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
815	  i.e. enables or disables monitoring on the Linux side.
816	  A custom interval value (in seconds) can be written to
817	  /proc/appldata/interval.
818
819	  Defaults are 60 seconds interval and timer off.
820	  The /proc entries can also be read from, showing the current settings.
821
822config APPLDATA_MEM
823	def_tristate m
824	prompt "Monitor memory management statistics"
825	depends on APPLDATA_BASE && VM_EVENT_COUNTERS
826	help
827	  This provides memory management related data to the Linux - VM Monitor
828	  Stream, like paging/swapping rate, memory utilisation, etc.
829	  Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
830	  APPLDATA monitor record, i.e. enables or disables monitoring this record
831	  on the z/VM side.
832
833	  Default is disabled.
834	  The /proc entry can also be read from, showing the current settings.
835
836	  This can also be compiled as a module, which will be called
837	  appldata_mem.o.
838
839config APPLDATA_OS
840	def_tristate m
841	prompt "Monitor OS statistics"
842	depends on APPLDATA_BASE
843	help
844	  This provides OS related data to the Linux - VM Monitor Stream, like
845	  CPU utilisation, etc.
846	  Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
847	  APPLDATA monitor record, i.e. enables or disables monitoring this record
848	  on the z/VM side.
849
850	  Default is disabled.
851	  This can also be compiled as a module, which will be called
852	  appldata_os.o.
853
854config APPLDATA_NET_SUM
855	def_tristate m
856	prompt "Monitor overall network statistics"
857	depends on APPLDATA_BASE && NET
858	help
859	  This provides network related data to the Linux - VM Monitor Stream,
860	  currently there is only a total sum of network I/O statistics, no
861	  per-interface data.
862	  Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
863	  APPLDATA monitor record, i.e. enables or disables monitoring this record
864	  on the z/VM side.
865
866	  Default is disabled.
867	  This can also be compiled as a module, which will be called
868	  appldata_net_sum.o.
869
870config S390_HYPFS_FS
871	def_bool y
872	prompt "s390 hypervisor file system support"
873	select SYS_HYPERVISOR
874	help
875	  This is a virtual file system intended to provide accounting
876	  information in an s390 hypervisor environment.
877
878source "arch/s390/kvm/Kconfig"
879
880config S390_GUEST
881	def_bool y
882	prompt "s390 support for virtio devices"
883	select TTY
884	select VIRTUALIZATION
885	select VIRTIO
886	help
887	  Enabling this option adds support for virtio based paravirtual device
888	  drivers on s390.
889
890	  Select this option if you want to run the kernel as a guest under
891	  the KVM hypervisor.
892
893endmenu
894
895config S390_MODULES_SANITY_TEST_HELPERS
896	def_bool n
897
898menu "Selftests"
899
900config S390_UNWIND_SELFTEST
901	def_tristate n
902	depends on KUNIT
903	default KUNIT_ALL_TESTS
904	prompt "Test unwind functions"
905	help
906	  This option enables s390 specific stack unwinder testing kernel
907	  module. This option is not useful for distributions or general
908	  kernels, but only for kernel developers working on architecture code.
909
910	  Say N if you are unsure.
911
912config S390_KPROBES_SANITY_TEST
913	def_tristate n
914	prompt "Enable s390 specific kprobes tests"
915	depends on KPROBES
916	depends on KUNIT
917	help
918	  This option enables an s390 specific kprobes test module. This option
919	  is not useful for distributions or general kernels, but only for kernel
920	  developers working on architecture code.
921
922	  Say N if you are unsure.
923
924config S390_MODULES_SANITY_TEST
925	def_tristate n
926	depends on KUNIT
927	default KUNIT_ALL_TESTS
928	prompt "Enable s390 specific modules tests"
929	select S390_MODULES_SANITY_TEST_HELPERS
930	help
931	  This option enables an s390 specific modules test. This option is
932	  not useful for distributions or general kernels, but only for
933	  kernel developers working on architecture code.
934
935	  Say N if you are unsure.
936endmenu
937