xref: /linux/arch/s390/Kconfig (revision d8c6b3fc918dd7b93c66e49ff8640746b84fbfe9)
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_KERNEL_PMD_MKWRITE
131	select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP
132	select BUILDTIME_TABLE_SORT
133	select CLONE_BACKWARDS2
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 if SLUB
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 KEXEC
220	select MMU_GATHER_MERGE_VMAS
221	select MMU_GATHER_NO_GATHER
222	select MMU_GATHER_RCU_TABLE_FREE
223	select MODULES_USE_ELF_RELA
224	select NEED_DMA_MAP_STATE	if PCI
225	select NEED_PER_CPU_EMBED_FIRST_CHUNK
226	select NEED_SG_DMA_LENGTH	if PCI
227	select OLD_SIGACTION
228	select OLD_SIGSUSPEND3
229	select PCI_DOMAINS		if PCI
230	select PCI_MSI			if PCI
231	select PCI_MSI_ARCH_FALLBACKS	if PCI_MSI
232	select SPARSE_IRQ
233	select SWIOTLB
234	select SYSCTL_EXCEPTION_TRACE
235	select THREAD_INFO_IN_TASK
236	select TRACE_IRQFLAGS_SUPPORT
237	select TTY
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 CRYPTO && CRYPTO_SHA256 && CRYPTO_SHA256_S390
256
257config ARCH_SUPPORTS_KEXEC_SIG
258	def_bool MODULE_SIG_FORMAT
259
260config ARCH_SUPPORTS_KEXEC_PURGATORY
261	def_bool KEXEC_FILE
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 y
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.  It is safe to say "Y".
457
458config SMP
459	def_bool y
460
461config NR_CPUS
462	int "Maximum number of CPUs (2-512)"
463	range 2 512
464	default "64"
465	help
466	  This allows you to specify the maximum number of CPUs which this
467	  kernel will support. The maximum supported value is 512 and the
468	  minimum value which makes sense is 2.
469
470	  This is purely to save memory - each supported CPU adds
471	  approximately sixteen kilobytes to the kernel image.
472
473config HOTPLUG_CPU
474	def_bool y
475
476config NUMA
477	bool "NUMA support"
478	depends on SCHED_TOPOLOGY
479	default n
480	help
481	  Enable NUMA support
482
483	  This option adds NUMA support to the kernel.
484
485config NODES_SHIFT
486	int
487	depends on NUMA
488	default "1"
489
490config SCHED_SMT
491	def_bool n
492
493config SCHED_MC
494	def_bool n
495
496config SCHED_TOPOLOGY
497	def_bool y
498	prompt "Topology scheduler support"
499	select SCHED_SMT
500	select SCHED_MC
501	help
502	  Topology scheduler support improves the CPU scheduler's decision
503	  making when dealing with machines that have multi-threading,
504	  multiple cores or multiple books.
505
506source "kernel/Kconfig.hz"
507
508config CERT_STORE
509	bool "Get user certificates via DIAG320"
510	depends on KEYS
511	select CRYPTO_LIB_SHA256
512	help
513	  Enable this option if you want to access user-provided secure boot
514	  certificates via DIAG 0x320.
515
516	  These certificates will be made available via the keyring named
517	  'cert_store'.
518
519config KERNEL_NOBP
520	def_bool n
521	prompt "Enable modified branch prediction for the kernel by default"
522	help
523	  If this option is selected the kernel will switch to a modified
524	  branch prediction mode if the firmware interface is available.
525	  The modified branch prediction mode improves the behaviour in
526	  regard to speculative execution.
527
528	  With the option enabled the kernel parameter "nobp=0" or "nospec"
529	  can be used to run the kernel in the normal branch prediction mode.
530
531	  With the option disabled the modified branch prediction mode is
532	  enabled with the "nobp=1" kernel parameter.
533
534	  If unsure, say N.
535
536config EXPOLINE
537	def_bool n
538	depends on $(cc-option,-mindirect-branch=thunk)
539	prompt "Avoid speculative indirect branches in the kernel"
540	help
541	  Compile the kernel with the expoline compiler options to guard
542	  against kernel-to-user data leaks by avoiding speculative indirect
543	  branches.
544	  Requires a compiler with -mindirect-branch=thunk support for full
545	  protection. The kernel may run slower.
546
547	  If unsure, say N.
548
549config EXPOLINE_EXTERN
550	def_bool n
551	depends on EXPOLINE
552	depends on CC_IS_GCC && GCC_VERSION >= 110200
553	depends on $(success,$(srctree)/arch/s390/tools/gcc-thunk-extern.sh $(CC))
554	prompt "Generate expolines as extern functions."
555	help
556	  This option is required for some tooling like kpatch. The kernel is
557	  compiled with -mindirect-branch=thunk-extern and requires a newer
558	  compiler.
559
560	  If unsure, say N.
561
562choice
563	prompt "Expoline default"
564	depends on EXPOLINE
565	default EXPOLINE_FULL
566
567config EXPOLINE_OFF
568	bool "spectre_v2=off"
569
570config EXPOLINE_AUTO
571	bool "spectre_v2=auto"
572
573config EXPOLINE_FULL
574	bool "spectre_v2=on"
575
576endchoice
577
578config RELOCATABLE
579	def_bool y
580	help
581	  This builds a kernel image that retains relocation information
582	  so it can be loaded at an arbitrary address.
583	  The kernel is linked as a position-independent executable (PIE)
584	  and contains dynamic relocations which are processed early in the
585	  bootup process.
586	  The relocations make the kernel image about 15% larger (compressed
587	  10%), but are discarded at runtime.
588	  Note: this option exists only for documentation purposes, please do
589	  not remove it.
590
591config RANDOMIZE_BASE
592	bool "Randomize the address of the kernel image (KASLR)"
593	default y
594	help
595	  In support of Kernel Address Space Layout Randomization (KASLR),
596	  this randomizes the address at which the kernel image is loaded,
597	  as a security feature that deters exploit attempts relying on
598	  knowledge of the location of kernel internals.
599
600endmenu
601
602menu "Memory setup"
603
604config ARCH_SPARSEMEM_ENABLE
605	def_bool y
606	select SPARSEMEM_VMEMMAP_ENABLE
607	select SPARSEMEM_VMEMMAP
608
609config ARCH_SPARSEMEM_DEFAULT
610	def_bool y
611
612config MAX_PHYSMEM_BITS
613	int "Maximum size of supported physical memory in bits (42-53)"
614	range 42 53
615	default "46"
616	help
617	  This option specifies the maximum supported size of physical memory
618	  in bits. Supported is any size between 2^42 (4TB) and 2^53 (8PB).
619	  Increasing the number of bits also increases the kernel image size.
620	  By default 46 bits (64TB) are supported.
621
622config CHECK_STACK
623	def_bool y
624	depends on !VMAP_STACK
625	prompt "Detect kernel stack overflow"
626	help
627	  This option enables the compiler option -mstack-guard and
628	  -mstack-size if they are available. If the compiler supports them
629	  it will emit additional code to each function prolog to trigger
630	  an illegal operation if the kernel stack is about to overflow.
631
632	  Say N if you are unsure.
633
634config STACK_GUARD
635	int "Size of the guard area (128-1024)"
636	range 128 1024
637	depends on CHECK_STACK
638	default "256"
639	help
640	  This allows you to specify the size of the guard area at the lower
641	  end of the kernel stack. If the kernel stack points into the guard
642	  area on function entry an illegal operation is triggered. The size
643	  needs to be a power of 2. Please keep in mind that the size of an
644	  interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
645	  The minimum size for the stack guard should be 256 for 31 bit and
646	  512 for 64 bit.
647
648endmenu
649
650menu "I/O subsystem"
651
652config QDIO
653	def_tristate y
654	prompt "QDIO support"
655	help
656	  This driver provides the Queued Direct I/O base support for
657	  IBM System z.
658
659	  To compile this driver as a module, choose M here: the
660	  module will be called qdio.
661
662	  If unsure, say Y.
663
664if PCI
665
666config PCI_NR_FUNCTIONS
667	int "Maximum number of PCI functions (1-4096)"
668	range 1 4096
669	default "512"
670	help
671	  This allows you to specify the maximum number of PCI functions which
672	  this kernel will support.
673
674endif # PCI
675
676config HAS_IOMEM
677	def_bool PCI
678
679config CHSC_SCH
680	def_tristate m
681	prompt "Support for CHSC subchannels"
682	help
683	  This driver allows usage of CHSC subchannels. A CHSC subchannel
684	  is usually present on LPAR only.
685	  The driver creates a device /dev/chsc, which may be used to
686	  obtain I/O configuration information about the machine and
687	  to issue asynchronous chsc commands (DANGEROUS).
688	  You will usually only want to use this interface on a special
689	  LPAR designated for system management.
690
691	  To compile this driver as a module, choose M here: the
692	  module will be called chsc_sch.
693
694	  If unsure, say N.
695
696config SCM_BUS
697	def_bool y
698	prompt "SCM bus driver"
699	help
700	  Bus driver for Storage Class Memory.
701
702config EADM_SCH
703	def_tristate m
704	prompt "Support for EADM subchannels"
705	depends on SCM_BUS
706	help
707	  This driver allows usage of EADM subchannels. EADM subchannels act
708	  as a communication vehicle for SCM increments.
709
710	  To compile this driver as a module, choose M here: the
711	  module will be called eadm_sch.
712
713config VFIO_CCW
714	def_tristate n
715	prompt "Support for VFIO-CCW subchannels"
716	depends on VFIO
717	select VFIO_MDEV
718	help
719	  This driver allows usage of I/O subchannels via VFIO-CCW.
720
721	  To compile this driver as a module, choose M here: the
722	  module will be called vfio_ccw.
723
724config VFIO_AP
725	def_tristate n
726	prompt "VFIO support for AP devices"
727	depends on KVM
728	depends on VFIO
729	depends on ZCRYPT
730	select VFIO_MDEV
731	help
732	  This driver grants access to Adjunct Processor (AP) devices
733	  via the VFIO mediated device interface.
734
735	  To compile this driver as a module, choose M here: the module
736	  will be called vfio_ap.
737
738endmenu
739
740config CCW
741	def_bool y
742
743config HAVE_PNETID
744	tristate
745	default (SMC || CCWGROUP)
746
747menu "Virtualization"
748
749config PROTECTED_VIRTUALIZATION_GUEST
750	def_bool n
751	prompt "Protected virtualization guest support"
752	help
753	  Select this option, if you want to be able to run this
754	  kernel as a protected virtualization KVM guest.
755	  Protected virtualization capable machines have a mini hypervisor
756	  located at machine level (an ultravisor). With help of the
757	  Ultravisor, KVM will be able to run "protected" VMs, special
758	  VMs whose memory and management data are unavailable to KVM.
759
760config PFAULT
761	def_bool y
762	prompt "Pseudo page fault support"
763	help
764	  Select this option, if you want to use PFAULT pseudo page fault
765	  handling under VM. If running native or in LPAR, this option
766	  has no effect. If your VM does not support PFAULT, PAGEEX
767	  pseudo page fault handling will be used.
768	  Note that VM 4.2 supports PFAULT but has a bug in its
769	  implementation that causes some problems.
770	  Everybody who wants to run Linux under VM != VM4.2 should select
771	  this option.
772
773config CMM
774	def_tristate n
775	prompt "Cooperative memory management"
776	help
777	  Select this option, if you want to enable the kernel interface
778	  to reduce the memory size of the system. This is accomplished
779	  by allocating pages of memory and put them "on hold". This only
780	  makes sense for a system running under VM where the unused pages
781	  will be reused by VM for other guest systems. The interface
782	  allows an external monitor to balance memory of many systems.
783	  Everybody who wants to run Linux under VM should select this
784	  option.
785
786config CMM_IUCV
787	def_bool y
788	prompt "IUCV special message interface to cooperative memory management"
789	depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
790	help
791	  Select this option to enable the special message interface to
792	  the cooperative memory management.
793
794config APPLDATA_BASE
795	def_bool n
796	prompt "Linux - VM Monitor Stream, base infrastructure"
797	depends on PROC_SYSCTL
798	help
799	  This provides a kernel interface for creating and updating z/VM APPLDATA
800	  monitor records. The monitor records are updated at certain time
801	  intervals, once the timer is started.
802	  Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
803	  i.e. enables or disables monitoring on the Linux side.
804	  A custom interval value (in seconds) can be written to
805	  /proc/appldata/interval.
806
807	  Defaults are 60 seconds interval and timer off.
808	  The /proc entries can also be read from, showing the current settings.
809
810config APPLDATA_MEM
811	def_tristate m
812	prompt "Monitor memory management statistics"
813	depends on APPLDATA_BASE && VM_EVENT_COUNTERS
814	help
815	  This provides memory management related data to the Linux - VM Monitor
816	  Stream, like paging/swapping rate, memory utilisation, etc.
817	  Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
818	  APPLDATA monitor record, i.e. enables or disables monitoring this record
819	  on the z/VM side.
820
821	  Default is disabled.
822	  The /proc entry can also be read from, showing the current settings.
823
824	  This can also be compiled as a module, which will be called
825	  appldata_mem.o.
826
827config APPLDATA_OS
828	def_tristate m
829	prompt "Monitor OS statistics"
830	depends on APPLDATA_BASE
831	help
832	  This provides OS related data to the Linux - VM Monitor Stream, like
833	  CPU utilisation, etc.
834	  Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
835	  APPLDATA monitor record, i.e. enables or disables monitoring this record
836	  on the z/VM side.
837
838	  Default is disabled.
839	  This can also be compiled as a module, which will be called
840	  appldata_os.o.
841
842config APPLDATA_NET_SUM
843	def_tristate m
844	prompt "Monitor overall network statistics"
845	depends on APPLDATA_BASE && NET
846	help
847	  This provides network related data to the Linux - VM Monitor Stream,
848	  currently there is only a total sum of network I/O statistics, no
849	  per-interface data.
850	  Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
851	  APPLDATA monitor record, i.e. enables or disables monitoring this record
852	  on the z/VM side.
853
854	  Default is disabled.
855	  This can also be compiled as a module, which will be called
856	  appldata_net_sum.o.
857
858config S390_HYPFS
859	def_bool y
860	prompt "s390 hypervisor information"
861	help
862	  This provides several binary files at (debugfs)/s390_hypfs/ to
863	  provide accounting information in an s390 hypervisor environment.
864
865config S390_HYPFS_FS
866	def_bool n
867	prompt "s390 hypervisor file system support"
868	select SYS_HYPERVISOR
869	depends on S390_HYPFS
870	help
871	  This is a virtual file system intended to provide accounting
872	  information in an s390 hypervisor environment. This file system
873	  is deprecated and should not be used.
874
875	  Say N if you are unsure.
876
877source "arch/s390/kvm/Kconfig"
878
879config S390_GUEST
880	def_bool y
881	prompt "s390 support for virtio devices"
882	select TTY
883	select VIRTUALIZATION
884	select VIRTIO
885	help
886	  Enabling this option adds support for virtio based paravirtual device
887	  drivers on s390.
888
889	  Select this option if you want to run the kernel as a guest under
890	  the KVM hypervisor.
891
892endmenu
893
894config S390_MODULES_SANITY_TEST_HELPERS
895	def_bool n
896
897menu "Selftests"
898
899config S390_UNWIND_SELFTEST
900	def_tristate n
901	depends on KUNIT
902	default KUNIT_ALL_TESTS
903	prompt "Test unwind functions"
904	help
905	  This option enables s390 specific stack unwinder testing kernel
906	  module. This option is not useful for distributions or general
907	  kernels, but only for kernel developers working on architecture code.
908
909	  Say N if you are unsure.
910
911config S390_KPROBES_SANITY_TEST
912	def_tristate n
913	prompt "Enable s390 specific kprobes tests"
914	depends on KPROBES
915	depends on KUNIT
916	help
917	  This option enables an s390 specific kprobes test module. This option
918	  is not useful for distributions or general kernels, but only for kernel
919	  developers working on architecture code.
920
921	  Say N if you are unsure.
922
923config S390_MODULES_SANITY_TEST
924	def_tristate n
925	depends on KUNIT
926	default KUNIT_ALL_TESTS
927	prompt "Enable s390 specific modules tests"
928	select S390_MODULES_SANITY_TEST_HELPERS
929	help
930	  This option enables an s390 specific modules test. This option is
931	  not useful for distributions or general kernels, but only for
932	  kernel developers working on architecture code.
933
934	  Say N if you are unsure.
935endmenu
936