xref: /linux/arch/s390/Kconfig (revision 76f623d2d4283cc36a9c8a5b585df74638f1efa5)
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_NO_INSTR
127	select ARCH_WANT_DEFAULT_BPF_JIT
128	select ARCH_WANT_IPC_PARSE_VERSION
129	select ARCH_WANT_KERNEL_PMD_MKWRITE
130	select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP
131	select BUILDTIME_TABLE_SORT
132	select CLONE_BACKWARDS2
133	select DCACHE_WORD_ACCESS if !KMSAN
134	select DMA_OPS if PCI
135	select DYNAMIC_FTRACE if FUNCTION_TRACER
136	select FUNCTION_ALIGNMENT_8B if CC_IS_GCC
137	select FUNCTION_ALIGNMENT_16B if !CC_IS_GCC
138	select GENERIC_ALLOCATOR
139	select GENERIC_CPU_AUTOPROBE
140	select GENERIC_CPU_VULNERABILITIES
141	select GENERIC_ENTRY
142	select GENERIC_GETTIMEOFDAY
143	select GENERIC_PTDUMP
144	select GENERIC_SMP_IDLE_THREAD
145	select GENERIC_TIME_VSYSCALL
146	select GENERIC_VDSO_TIME_NS
147	select GENERIC_IOREMAP if PCI
148	select HAVE_ALIGNED_STRUCT_PAGE
149	select HAVE_ARCH_AUDITSYSCALL
150	select HAVE_ARCH_JUMP_LABEL
151	select HAVE_ARCH_JUMP_LABEL_RELATIVE
152	select HAVE_ARCH_KASAN
153	select HAVE_ARCH_KASAN_VMALLOC
154	select HAVE_ARCH_KCSAN
155	select HAVE_ARCH_KFENCE
156	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
157	select HAVE_ARCH_SECCOMP_FILTER
158	select HAVE_ARCH_SOFT_DIRTY
159	select HAVE_ARCH_STACKLEAK
160	select HAVE_ARCH_TRACEHOOK
161	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
162	select HAVE_ARCH_VMAP_STACK
163	select HAVE_ASM_MODVERSIONS
164	select HAVE_CMPXCHG_DOUBLE
165	select HAVE_CMPXCHG_LOCAL
166	select HAVE_DEBUG_KMEMLEAK
167	select HAVE_DMA_CONTIGUOUS
168	select HAVE_DYNAMIC_FTRACE
169	select HAVE_DYNAMIC_FTRACE_WITH_ARGS
170	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
171	select HAVE_DYNAMIC_FTRACE_WITH_REGS
172	select HAVE_EBPF_JIT if HAVE_MARCH_Z196_FEATURES
173	select HAVE_EFFICIENT_UNALIGNED_ACCESS
174	select HAVE_FAST_GUP
175	select HAVE_FENTRY
176	select HAVE_FTRACE_MCOUNT_RECORD
177	select HAVE_FUNCTION_ARG_ACCESS_API
178	select HAVE_FUNCTION_ERROR_INJECTION
179	select HAVE_FUNCTION_GRAPH_RETVAL
180	select HAVE_FUNCTION_GRAPH_TRACER
181	select HAVE_FUNCTION_TRACER
182	select HAVE_GCC_PLUGINS
183	select HAVE_GENERIC_VDSO
184	select HAVE_IOREMAP_PROT if PCI
185	select HAVE_KERNEL_BZIP2
186	select HAVE_KERNEL_GZIP
187	select HAVE_KERNEL_LZ4
188	select HAVE_KERNEL_LZMA
189	select HAVE_KERNEL_LZO
190	select HAVE_KERNEL_UNCOMPRESSED
191	select HAVE_KERNEL_XZ
192	select HAVE_KERNEL_ZSTD
193	select HAVE_KPROBES
194	select HAVE_KPROBES_ON_FTRACE
195	select HAVE_KRETPROBES
196	select HAVE_KVM
197	select HAVE_LIVEPATCH
198	select HAVE_MEMBLOCK_PHYS_MAP
199	select HAVE_MOD_ARCH_SPECIFIC
200	select HAVE_NMI
201	select HAVE_NOP_MCOUNT
202	select HAVE_PCI
203	select HAVE_PERF_EVENTS
204	select HAVE_PERF_REGS
205	select HAVE_PERF_USER_STACK_DUMP
206	select HAVE_REGS_AND_STACK_ACCESS_API
207	select HAVE_RELIABLE_STACKTRACE
208	select HAVE_RETHOOK
209	select HAVE_RSEQ
210	select HAVE_SAMPLE_FTRACE_DIRECT
211	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI
212	select HAVE_SETUP_PER_CPU_AREA
213	select HAVE_SOFTIRQ_ON_OWN_STACK
214	select HAVE_SYSCALL_TRACEPOINTS
215	select HAVE_VIRT_CPU_ACCOUNTING
216	select HAVE_VIRT_CPU_ACCOUNTING_IDLE
217	select IOMMU_HELPER		if PCI
218	select IOMMU_SUPPORT		if PCI
219	select MMU_GATHER_MERGE_VMAS
220	select MMU_GATHER_NO_GATHER
221	select MMU_GATHER_RCU_TABLE_FREE
222	select MODULES_USE_ELF_RELA
223	select NEED_DMA_MAP_STATE	if PCI
224	select NEED_PER_CPU_EMBED_FIRST_CHUNK
225	select NEED_SG_DMA_LENGTH	if PCI
226	select OLD_SIGACTION
227	select OLD_SIGSUSPEND3
228	select PCI_DOMAINS		if PCI
229	select PCI_MSI			if PCI
230	select PCI_MSI_ARCH_FALLBACKS	if PCI_MSI
231	select SPARSE_IRQ
232	select SWIOTLB
233	select SYSCTL_EXCEPTION_TRACE
234	select THREAD_INFO_IN_TASK
235	select TRACE_IRQFLAGS_SUPPORT
236	select TTY
237	select USER_STACKTRACE_SUPPORT
238	select VIRT_CPU_ACCOUNTING
239	select ZONE_DMA
240	# Note: keep the above list sorted alphabetically
241
242config SCHED_OMIT_FRAME_POINTER
243	def_bool y
244
245config PGTABLE_LEVELS
246	int
247	default 5
248
249source "kernel/livepatch/Kconfig"
250
251config ARCH_SUPPORTS_KEXEC
252	def_bool y
253
254config ARCH_SUPPORTS_KEXEC_FILE
255	def_bool y
256
257config ARCH_SUPPORTS_KEXEC_SIG
258	def_bool MODULE_SIG_FORMAT
259
260config ARCH_SUPPORTS_KEXEC_PURGATORY
261	def_bool y
262
263config ARCH_SUPPORTS_CRASH_DUMP
264	def_bool y
265	help
266	  Refer to <file:Documentation/arch/s390/zfcpdump.rst> for more details on this.
267	  This option also enables s390 zfcpdump.
268	  See also <file:Documentation/arch/s390/zfcpdump.rst>
269
270menu "Processor type and features"
271
272config HAVE_MARCH_Z10_FEATURES
273	def_bool n
274
275config HAVE_MARCH_Z196_FEATURES
276	def_bool n
277	select HAVE_MARCH_Z10_FEATURES
278
279config HAVE_MARCH_ZEC12_FEATURES
280	def_bool n
281	select HAVE_MARCH_Z196_FEATURES
282
283config HAVE_MARCH_Z13_FEATURES
284	def_bool n
285	select HAVE_MARCH_ZEC12_FEATURES
286
287config HAVE_MARCH_Z14_FEATURES
288	def_bool n
289	select HAVE_MARCH_Z13_FEATURES
290
291config HAVE_MARCH_Z15_FEATURES
292	def_bool n
293	select HAVE_MARCH_Z14_FEATURES
294
295config HAVE_MARCH_Z16_FEATURES
296	def_bool n
297	select HAVE_MARCH_Z15_FEATURES
298
299choice
300	prompt "Processor type"
301	default MARCH_Z196
302
303config MARCH_Z10
304	bool "IBM System z10"
305	select HAVE_MARCH_Z10_FEATURES
306	depends on $(cc-option,-march=z10)
307	help
308	  Select this to enable optimizations for IBM System z10 (2097 and 2098
309	  series). This is the oldest machine generation currently supported.
310
311config MARCH_Z196
312	bool "IBM zEnterprise 114 and 196"
313	select HAVE_MARCH_Z196_FEATURES
314	depends on $(cc-option,-march=z196)
315	help
316	  Select this to enable optimizations for IBM zEnterprise 114 and 196
317	  (2818 and 2817 series). The kernel will be slightly faster but will
318	  not work on older machines.
319
320config MARCH_ZEC12
321	bool "IBM zBC12 and zEC12"
322	select HAVE_MARCH_ZEC12_FEATURES
323	depends on $(cc-option,-march=zEC12)
324	help
325	  Select this to enable optimizations for IBM zBC12 and zEC12 (2828 and
326	  2827 series). The kernel will be slightly faster but will not work on
327	  older machines.
328
329config MARCH_Z13
330	bool "IBM z13s and z13"
331	select HAVE_MARCH_Z13_FEATURES
332	depends on $(cc-option,-march=z13)
333	help
334	  Select this to enable optimizations for IBM z13s and z13 (2965 and
335	  2964 series). The kernel will be slightly faster but will not work on
336	  older machines.
337
338config MARCH_Z14
339	bool "IBM z14 ZR1 and z14"
340	select HAVE_MARCH_Z14_FEATURES
341	depends on $(cc-option,-march=z14)
342	help
343	  Select this to enable optimizations for IBM z14 ZR1 and z14 (3907
344	  and 3906 series). The kernel will be slightly faster but will not
345	  work on older machines.
346
347config MARCH_Z15
348	bool "IBM z15"
349	select HAVE_MARCH_Z15_FEATURES
350	depends on $(cc-option,-march=z15)
351	help
352	  Select this to enable optimizations for IBM z15 (8562
353	  and 8561 series). The kernel will be slightly faster but will not
354	  work on older machines.
355
356config MARCH_Z16
357	bool "IBM z16"
358	select HAVE_MARCH_Z16_FEATURES
359	depends on $(cc-option,-march=z16)
360	help
361	  Select this to enable optimizations for IBM z16 (3931 and
362	  3932 series).
363
364endchoice
365
366config MARCH_Z10_TUNE
367	def_bool TUNE_Z10 || MARCH_Z10 && TUNE_DEFAULT
368
369config MARCH_Z196_TUNE
370	def_bool TUNE_Z196 || MARCH_Z196 && TUNE_DEFAULT
371
372config MARCH_ZEC12_TUNE
373	def_bool TUNE_ZEC12 || MARCH_ZEC12 && TUNE_DEFAULT
374
375config MARCH_Z13_TUNE
376	def_bool TUNE_Z13 || MARCH_Z13 && TUNE_DEFAULT
377
378config MARCH_Z14_TUNE
379	def_bool TUNE_Z14 || MARCH_Z14 && TUNE_DEFAULT
380
381config MARCH_Z15_TUNE
382	def_bool TUNE_Z15 || MARCH_Z15 && TUNE_DEFAULT
383
384config MARCH_Z16_TUNE
385	def_bool TUNE_Z16 || MARCH_Z16 && TUNE_DEFAULT
386
387choice
388	prompt "Tune code generation"
389	default TUNE_DEFAULT
390	help
391	  Cause the compiler to tune (-mtune) the generated code for a machine.
392	  This will make the code run faster on the selected machine but
393	  somewhat slower on other machines.
394	  This option only changes how the compiler emits instructions, not the
395	  selection of instructions itself, so the resulting kernel will run on
396	  all other machines.
397
398config TUNE_DEFAULT
399	bool "Default"
400	help
401	  Tune the generated code for the target processor for which the kernel
402	  will be compiled.
403
404config TUNE_Z10
405	bool "IBM System 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
427config TUNE_Z16
428	bool "IBM z16"
429	depends on $(cc-option,-mtune=z16)
430
431endchoice
432
433config 64BIT
434	def_bool y
435
436config COMMAND_LINE_SIZE
437	int "Maximum size of kernel command line"
438	default 4096
439	range 896 1048576
440	help
441	  This allows you to specify the maximum length of the kernel command
442	  line.
443
444config COMPAT
445	def_bool n
446	prompt "Kernel support for 31 bit emulation"
447	select ARCH_WANT_OLD_COMPAT_IPC
448	select COMPAT_OLD_SIGACTION
449	select HAVE_UID16
450	depends on MULTIUSER
451	depends on !CC_IS_CLANG
452	help
453	  Select this option if you want to enable your system kernel to
454	  handle system-calls from ELF binaries for 31 bit ESA.  This option
455	  (and some other stuff like libraries and such) is needed for
456	  executing 31 bit applications.
457
458	  If unsure say N.
459
460config SMP
461	def_bool y
462
463config NR_CPUS
464	int "Maximum number of CPUs (2-512)"
465	range 2 512
466	default "64"
467	help
468	  This allows you to specify the maximum number of CPUs which this
469	  kernel will support. The maximum supported value is 512 and the
470	  minimum value which makes sense is 2.
471
472	  This is purely to save memory - each supported CPU adds
473	  approximately sixteen kilobytes to the kernel image.
474
475config HOTPLUG_CPU
476	def_bool y
477
478config NUMA
479	bool "NUMA support"
480	depends on SCHED_TOPOLOGY
481	default n
482	help
483	  Enable NUMA support
484
485	  This option adds NUMA support to the kernel.
486
487config NODES_SHIFT
488	int
489	depends on NUMA
490	default "1"
491
492config SCHED_SMT
493	def_bool n
494
495config SCHED_MC
496	def_bool n
497
498config SCHED_TOPOLOGY
499	def_bool y
500	prompt "Topology scheduler support"
501	select SCHED_SMT
502	select SCHED_MC
503	help
504	  Topology scheduler support improves the CPU scheduler's decision
505	  making when dealing with machines that have multi-threading,
506	  multiple cores or multiple books.
507
508source "kernel/Kconfig.hz"
509
510config CERT_STORE
511	bool "Get user certificates via DIAG320"
512	depends on KEYS
513	select CRYPTO_LIB_SHA256
514	help
515	  Enable this option if you want to access user-provided secure boot
516	  certificates via DIAG 0x320.
517
518	  These certificates will be made available via the keyring named
519	  'cert_store'.
520
521config KERNEL_NOBP
522	def_bool n
523	prompt "Enable modified branch prediction for the kernel by default"
524	help
525	  If this option is selected the kernel will switch to a modified
526	  branch prediction mode if the firmware interface is available.
527	  The modified branch prediction mode improves the behaviour in
528	  regard to speculative execution.
529
530	  With the option enabled the kernel parameter "nobp=0" or "nospec"
531	  can be used to run the kernel in the normal branch prediction mode.
532
533	  With the option disabled the modified branch prediction mode is
534	  enabled with the "nobp=1" kernel parameter.
535
536	  If unsure, say N.
537
538config EXPOLINE
539	def_bool n
540	depends on $(cc-option,-mindirect-branch=thunk)
541	prompt "Avoid speculative indirect branches in the kernel"
542	help
543	  Compile the kernel with the expoline compiler options to guard
544	  against kernel-to-user data leaks by avoiding speculative indirect
545	  branches.
546	  Requires a compiler with -mindirect-branch=thunk support for full
547	  protection. The kernel may run slower.
548
549	  If unsure, say N.
550
551config EXPOLINE_EXTERN
552	def_bool n
553	depends on EXPOLINE
554	depends on CC_IS_GCC && GCC_VERSION >= 110200
555	depends on $(success,$(srctree)/arch/s390/tools/gcc-thunk-extern.sh $(CC))
556	prompt "Generate expolines as extern functions."
557	help
558	  This option is required for some tooling like kpatch. The kernel is
559	  compiled with -mindirect-branch=thunk-extern and requires a newer
560	  compiler.
561
562	  If unsure, say N.
563
564choice
565	prompt "Expoline default"
566	depends on EXPOLINE
567	default EXPOLINE_FULL
568
569config EXPOLINE_OFF
570	bool "spectre_v2=off"
571
572config EXPOLINE_AUTO
573	bool "spectre_v2=auto"
574
575config EXPOLINE_FULL
576	bool "spectre_v2=on"
577
578endchoice
579
580config RELOCATABLE
581	def_bool y
582	help
583	  This builds a kernel image that retains relocation information
584	  so it can be loaded at an arbitrary address.
585	  The kernel is linked as a position-independent executable (PIE)
586	  and contains dynamic relocations which are processed early in the
587	  bootup process.
588	  The relocations make the kernel image about 15% larger (compressed
589	  10%), but are discarded at runtime.
590	  Note: this option exists only for documentation purposes, please do
591	  not remove it.
592
593config RANDOMIZE_BASE
594	bool "Randomize the address of the kernel image (KASLR)"
595	default y
596	help
597	  In support of Kernel Address Space Layout Randomization (KASLR),
598	  this randomizes the address at which the kernel image is loaded,
599	  as a security feature that deters exploit attempts relying on
600	  knowledge of the location of kernel internals.
601
602endmenu
603
604menu "Memory setup"
605
606config ARCH_SPARSEMEM_ENABLE
607	def_bool y
608	select SPARSEMEM_VMEMMAP_ENABLE
609	select SPARSEMEM_VMEMMAP
610
611config ARCH_SPARSEMEM_DEFAULT
612	def_bool y
613
614config MAX_PHYSMEM_BITS
615	int "Maximum size of supported physical memory in bits (42-53)"
616	range 42 53
617	default "46"
618	help
619	  This option specifies the maximum supported size of physical memory
620	  in bits. Supported is any size between 2^42 (4TB) and 2^53 (8PB).
621	  Increasing the number of bits also increases the kernel image size.
622	  By default 46 bits (64TB) are supported.
623
624config CHECK_STACK
625	def_bool y
626	depends on !VMAP_STACK
627	prompt "Detect kernel stack overflow"
628	help
629	  This option enables the compiler option -mstack-guard and
630	  -mstack-size if they are available. If the compiler supports them
631	  it will emit additional code to each function prolog to trigger
632	  an illegal operation if the kernel stack is about to overflow.
633
634	  Say N if you are unsure.
635
636config STACK_GUARD
637	int "Size of the guard area (128-1024)"
638	range 128 1024
639	depends on CHECK_STACK
640	default "256"
641	help
642	  This allows you to specify the size of the guard area at the lower
643	  end of the kernel stack. If the kernel stack points into the guard
644	  area on function entry an illegal operation is triggered. The size
645	  needs to be a power of 2. Please keep in mind that the size of an
646	  interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
647	  The minimum size for the stack guard should be 256 for 31 bit and
648	  512 for 64 bit.
649
650endmenu
651
652menu "I/O subsystem"
653
654config QDIO
655	def_tristate y
656	prompt "QDIO support"
657	help
658	  This driver provides the Queued Direct I/O base support for
659	  IBM System z.
660
661	  To compile this driver as a module, choose M here: the
662	  module will be called qdio.
663
664	  If unsure, say Y.
665
666if PCI
667
668config PCI_NR_FUNCTIONS
669	int "Maximum number of PCI functions (1-4096)"
670	range 1 4096
671	default "512"
672	help
673	  This allows you to specify the maximum number of PCI functions which
674	  this kernel will support.
675
676endif # PCI
677
678config HAS_IOMEM
679	def_bool PCI
680
681config CHSC_SCH
682	def_tristate m
683	prompt "Support for CHSC subchannels"
684	help
685	  This driver allows usage of CHSC subchannels. A CHSC subchannel
686	  is usually present on LPAR only.
687	  The driver creates a device /dev/chsc, which may be used to
688	  obtain I/O configuration information about the machine and
689	  to issue asynchronous chsc commands (DANGEROUS).
690	  You will usually only want to use this interface on a special
691	  LPAR designated for system management.
692
693	  To compile this driver as a module, choose M here: the
694	  module will be called chsc_sch.
695
696	  If unsure, say N.
697
698config SCM_BUS
699	def_bool y
700	prompt "SCM bus driver"
701	help
702	  Bus driver for Storage Class Memory.
703
704config EADM_SCH
705	def_tristate m
706	prompt "Support for EADM subchannels"
707	depends on SCM_BUS
708	help
709	  This driver allows usage of EADM subchannels. EADM subchannels act
710	  as a communication vehicle for SCM increments.
711
712	  To compile this driver as a module, choose M here: the
713	  module will be called eadm_sch.
714
715config VFIO_CCW
716	def_tristate n
717	prompt "Support for VFIO-CCW subchannels"
718	depends on VFIO
719	select VFIO_MDEV
720	help
721	  This driver allows usage of I/O subchannels via VFIO-CCW.
722
723	  To compile this driver as a module, choose M here: the
724	  module will be called vfio_ccw.
725
726config VFIO_AP
727	def_tristate n
728	prompt "VFIO support for AP devices"
729	depends on KVM
730	depends on VFIO
731	depends on ZCRYPT
732	select VFIO_MDEV
733	help
734	  This driver grants access to Adjunct Processor (AP) devices
735	  via the VFIO mediated device interface.
736
737	  To compile this driver as a module, choose M here: the module
738	  will be called vfio_ap.
739
740endmenu
741
742config CCW
743	def_bool y
744
745config HAVE_PNETID
746	tristate
747	default (SMC || CCWGROUP)
748
749menu "Virtualization"
750
751config PROTECTED_VIRTUALIZATION_GUEST
752	def_bool n
753	prompt "Protected virtualization guest support"
754	help
755	  Select this option, if you want to be able to run this
756	  kernel as a protected virtualization KVM guest.
757	  Protected virtualization capable machines have a mini hypervisor
758	  located at machine level (an ultravisor). With help of the
759	  Ultravisor, KVM will be able to run "protected" VMs, special
760	  VMs whose memory and management data are unavailable to KVM.
761
762config PFAULT
763	def_bool y
764	prompt "Pseudo page fault support"
765	help
766	  Select this option, if you want to use PFAULT pseudo page fault
767	  handling under VM. If running native or in LPAR, this option
768	  has no effect. If your VM does not support PFAULT, PAGEEX
769	  pseudo page fault handling will be used.
770	  Note that VM 4.2 supports PFAULT but has a bug in its
771	  implementation that causes some problems.
772	  Everybody who wants to run Linux under VM != VM4.2 should select
773	  this option.
774
775config CMM
776	def_tristate n
777	prompt "Cooperative memory management"
778	help
779	  Select this option, if you want to enable the kernel interface
780	  to reduce the memory size of the system. This is accomplished
781	  by allocating pages of memory and put them "on hold". This only
782	  makes sense for a system running under VM where the unused pages
783	  will be reused by VM for other guest systems. The interface
784	  allows an external monitor to balance memory of many systems.
785	  Everybody who wants to run Linux under VM should select this
786	  option.
787
788config CMM_IUCV
789	def_bool y
790	prompt "IUCV special message interface to cooperative memory management"
791	depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
792	help
793	  Select this option to enable the special message interface to
794	  the cooperative memory management.
795
796config APPLDATA_BASE
797	def_bool n
798	prompt "Linux - VM Monitor Stream, base infrastructure"
799	depends on PROC_SYSCTL
800	help
801	  This provides a kernel interface for creating and updating z/VM APPLDATA
802	  monitor records. The monitor records are updated at certain time
803	  intervals, once the timer is started.
804	  Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
805	  i.e. enables or disables monitoring on the Linux side.
806	  A custom interval value (in seconds) can be written to
807	  /proc/appldata/interval.
808
809	  Defaults are 60 seconds interval and timer off.
810	  The /proc entries can also be read from, showing the current settings.
811
812config APPLDATA_MEM
813	def_tristate m
814	prompt "Monitor memory management statistics"
815	depends on APPLDATA_BASE && VM_EVENT_COUNTERS
816	help
817	  This provides memory management related data to the Linux - VM Monitor
818	  Stream, like paging/swapping rate, memory utilisation, etc.
819	  Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
820	  APPLDATA monitor record, i.e. enables or disables monitoring this record
821	  on the z/VM side.
822
823	  Default is disabled.
824	  The /proc entry can also be read from, showing the current settings.
825
826	  This can also be compiled as a module, which will be called
827	  appldata_mem.o.
828
829config APPLDATA_OS
830	def_tristate m
831	prompt "Monitor OS statistics"
832	depends on APPLDATA_BASE
833	help
834	  This provides OS related data to the Linux - VM Monitor Stream, like
835	  CPU utilisation, etc.
836	  Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
837	  APPLDATA monitor record, i.e. enables or disables monitoring this record
838	  on the z/VM side.
839
840	  Default is disabled.
841	  This can also be compiled as a module, which will be called
842	  appldata_os.o.
843
844config APPLDATA_NET_SUM
845	def_tristate m
846	prompt "Monitor overall network statistics"
847	depends on APPLDATA_BASE && NET
848	help
849	  This provides network related data to the Linux - VM Monitor Stream,
850	  currently there is only a total sum of network I/O statistics, no
851	  per-interface data.
852	  Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
853	  APPLDATA monitor record, i.e. enables or disables monitoring this record
854	  on the z/VM side.
855
856	  Default is disabled.
857	  This can also be compiled as a module, which will be called
858	  appldata_net_sum.o.
859
860config S390_HYPFS
861	def_bool y
862	prompt "s390 hypervisor information"
863	help
864	  This provides several binary files at (debugfs)/s390_hypfs/ to
865	  provide accounting information in an s390 hypervisor environment.
866
867config S390_HYPFS_FS
868	def_bool n
869	prompt "s390 hypervisor file system support"
870	select SYS_HYPERVISOR
871	depends on S390_HYPFS
872	help
873	  This is a virtual file system intended to provide accounting
874	  information in an s390 hypervisor environment. This file system
875	  is deprecated and should not be used.
876
877	  Say N if you are unsure.
878
879source "arch/s390/kvm/Kconfig"
880
881config S390_GUEST
882	def_bool y
883	prompt "s390 support for virtio devices"
884	select TTY
885	select VIRTUALIZATION
886	select VIRTIO
887	help
888	  Enabling this option adds support for virtio based paravirtual device
889	  drivers on s390.
890
891	  Select this option if you want to run the kernel as a guest under
892	  the KVM hypervisor.
893
894endmenu
895
896config S390_MODULES_SANITY_TEST_HELPERS
897	def_bool n
898
899menu "Selftests"
900
901config S390_UNWIND_SELFTEST
902	def_tristate n
903	depends on KUNIT
904	default KUNIT_ALL_TESTS
905	prompt "Test unwind functions"
906	help
907	  This option enables s390 specific stack unwinder testing kernel
908	  module. This option is not useful for distributions or general
909	  kernels, but only for kernel developers working on architecture code.
910
911	  Say N if you are unsure.
912
913config S390_KPROBES_SANITY_TEST
914	def_tristate n
915	prompt "Enable s390 specific kprobes tests"
916	depends on KPROBES
917	depends on KUNIT
918	help
919	  This option enables an s390 specific kprobes test module. This option
920	  is not useful for distributions or general kernels, but only for kernel
921	  developers working on architecture code.
922
923	  Say N if you are unsure.
924
925config S390_MODULES_SANITY_TEST
926	def_tristate n
927	depends on KUNIT
928	default KUNIT_ALL_TESTS
929	prompt "Enable s390 specific modules tests"
930	select S390_MODULES_SANITY_TEST_HELPERS
931	help
932	  This option enables an s390 specific modules test. This option is
933	  not useful for distributions or general kernels, but only for
934	  kernel developers working on architecture code.
935
936	  Say N if you are unsure.
937endmenu
938