xref: /linux/arch/s390/Kconfig (revision 37744feebc086908fd89760650f458ab19071750)
1# SPDX-License-Identifier: GPL-2.0
2config MMU
3	def_bool y
4
5config ZONE_DMA
6	def_bool y
7
8config CPU_BIG_ENDIAN
9	def_bool y
10
11config LOCKDEP_SUPPORT
12	def_bool y
13
14config STACKTRACE_SUPPORT
15	def_bool y
16
17config ARCH_HAS_ILOG2_U32
18	def_bool n
19
20config ARCH_HAS_ILOG2_U64
21	def_bool n
22
23config GENERIC_HWEIGHT
24	def_bool y
25
26config GENERIC_BUG
27	def_bool y if BUG
28
29config GENERIC_BUG_RELATIVE_POINTERS
30	def_bool y
31
32config GENERIC_LOCKBREAK
33	def_bool y if PREEMPTTION
34
35config PGSTE
36	def_bool y if KVM
37
38config ARCH_SUPPORTS_DEBUG_PAGEALLOC
39	def_bool y
40
41config AUDIT_ARCH
42	def_bool y
43
44config NO_IOPORT_MAP
45	def_bool y
46
47config PCI_QUIRKS
48	def_bool n
49
50config ARCH_SUPPORTS_UPROBES
51	def_bool y
52
53config KASAN_SHADOW_OFFSET
54	hex
55	depends on KASAN
56	default 0x18000000000000 if KASAN_S390_4_LEVEL_PAGING
57	default 0x30000000000
58
59config S390
60	def_bool y
61	select ARCH_BINFMT_ELF_STATE
62	select ARCH_HAS_DEVMEM_IS_ALLOWED
63	select ARCH_HAS_ELF_RANDOMIZE
64	select ARCH_HAS_FORTIFY_SOURCE
65	select ARCH_HAS_GCOV_PROFILE_ALL
66	select ARCH_HAS_GIGANTIC_PAGE
67	select ARCH_HAS_KCOV
68	select ARCH_HAS_MEM_ENCRYPT
69	select ARCH_HAS_PTE_SPECIAL
70	select ARCH_HAS_SET_MEMORY
71	select ARCH_HAS_STRICT_KERNEL_RWX
72	select ARCH_HAS_STRICT_MODULE_RWX
73	select ARCH_HAS_SYSCALL_WRAPPER
74	select ARCH_HAS_UBSAN_SANITIZE_ALL
75	select ARCH_HAVE_NMI_SAFE_CMPXCHG
76	select ARCH_INLINE_READ_LOCK
77	select ARCH_INLINE_READ_LOCK_BH
78	select ARCH_INLINE_READ_LOCK_IRQ
79	select ARCH_INLINE_READ_LOCK_IRQSAVE
80	select ARCH_INLINE_READ_TRYLOCK
81	select ARCH_INLINE_READ_UNLOCK
82	select ARCH_INLINE_READ_UNLOCK_BH
83	select ARCH_INLINE_READ_UNLOCK_IRQ
84	select ARCH_INLINE_READ_UNLOCK_IRQRESTORE
85	select ARCH_INLINE_SPIN_LOCK
86	select ARCH_INLINE_SPIN_LOCK_BH
87	select ARCH_INLINE_SPIN_LOCK_IRQ
88	select ARCH_INLINE_SPIN_LOCK_IRQSAVE
89	select ARCH_INLINE_SPIN_TRYLOCK
90	select ARCH_INLINE_SPIN_TRYLOCK_BH
91	select ARCH_INLINE_SPIN_UNLOCK
92	select ARCH_INLINE_SPIN_UNLOCK_BH
93	select ARCH_INLINE_SPIN_UNLOCK_IRQ
94	select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE
95	select ARCH_INLINE_WRITE_LOCK
96	select ARCH_INLINE_WRITE_LOCK_BH
97	select ARCH_INLINE_WRITE_LOCK_IRQ
98	select ARCH_INLINE_WRITE_LOCK_IRQSAVE
99	select ARCH_INLINE_WRITE_TRYLOCK
100	select ARCH_INLINE_WRITE_UNLOCK
101	select ARCH_INLINE_WRITE_UNLOCK_BH
102	select ARCH_INLINE_WRITE_UNLOCK_IRQ
103	select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
104	select ARCH_KEEP_MEMBLOCK
105	select ARCH_STACKWALK
106	select ARCH_SUPPORTS_ATOMIC_RMW
107	select ARCH_SUPPORTS_NUMA_BALANCING
108	select ARCH_USE_BUILTIN_BSWAP
109	select ARCH_USE_CMPXCHG_LOCKREF
110	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
111	select ARCH_WANT_DEFAULT_BPF_JIT
112	select ARCH_WANT_IPC_PARSE_VERSION
113	select BUILDTIME_TABLE_SORT
114	select CLONE_BACKWARDS2
115	select DYNAMIC_FTRACE if FUNCTION_TRACER
116	select GENERIC_CLOCKEVENTS
117	select GENERIC_CPU_AUTOPROBE
118	select GENERIC_CPU_VULNERABILITIES
119	select GENERIC_FIND_FIRST_BIT
120	select GENERIC_SMP_IDLE_THREAD
121	select GENERIC_TIME_VSYSCALL
122	select HAVE_ALIGNED_STRUCT_PAGE if SLUB
123	select HAVE_ARCH_AUDITSYSCALL
124	select HAVE_ARCH_JUMP_LABEL
125	select HAVE_ARCH_JUMP_LABEL_RELATIVE
126	select HAVE_ARCH_KASAN
127	select HAVE_ARCH_KASAN_VMALLOC
128	select CPU_NO_EFFICIENT_FFS if !HAVE_MARCH_Z9_109_FEATURES
129	select HAVE_ARCH_SECCOMP_FILTER
130	select HAVE_ARCH_SOFT_DIRTY
131	select HAVE_ARCH_TRACEHOOK
132	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
133	select HAVE_ARCH_VMAP_STACK
134	select HAVE_ASM_MODVERSIONS
135	select HAVE_EBPF_JIT if PACK_STACK && HAVE_MARCH_Z196_FEATURES
136	select HAVE_CMPXCHG_DOUBLE
137	select HAVE_CMPXCHG_LOCAL
138	select HAVE_COPY_THREAD_TLS
139	select HAVE_DEBUG_KMEMLEAK
140	select HAVE_DMA_CONTIGUOUS
141	select HAVE_DYNAMIC_FTRACE
142	select HAVE_DYNAMIC_FTRACE_WITH_REGS
143	select HAVE_FAST_GUP
144	select HAVE_EFFICIENT_UNALIGNED_ACCESS
145	select HAVE_FENTRY
146	select HAVE_FTRACE_MCOUNT_RECORD
147	select HAVE_FUNCTION_GRAPH_TRACER
148	select HAVE_FUNCTION_TRACER
149	select HAVE_FUTEX_CMPXCHG if FUTEX
150	select HAVE_GCC_PLUGINS
151	select HAVE_KERNEL_BZIP2
152	select HAVE_KERNEL_GZIP
153	select HAVE_KERNEL_LZ4
154	select HAVE_KERNEL_LZMA
155	select HAVE_KERNEL_LZO
156	select HAVE_KERNEL_UNCOMPRESSED
157	select HAVE_KERNEL_XZ
158	select HAVE_KPROBES
159	select HAVE_KPROBES_ON_FTRACE
160	select HAVE_KRETPROBES
161	select HAVE_KVM
162	select HAVE_LIVEPATCH
163	select HAVE_PERF_REGS
164	select HAVE_PERF_USER_STACK_DUMP
165	select HAVE_MEMBLOCK_NODE_MAP
166	select HAVE_MEMBLOCK_PHYS_MAP
167	select MMU_GATHER_NO_GATHER
168	select HAVE_MOD_ARCH_SPECIFIC
169	select HAVE_NOP_MCOUNT
170	select HAVE_OPROFILE
171	select HAVE_PCI
172	select HAVE_PERF_EVENTS
173	select MMU_GATHER_RCU_TABLE_FREE
174	select HAVE_REGS_AND_STACK_ACCESS_API
175	select HAVE_RELIABLE_STACKTRACE
176	select HAVE_RSEQ
177	select HAVE_SYSCALL_TRACEPOINTS
178	select HAVE_VIRT_CPU_ACCOUNTING
179	select IOMMU_HELPER		if PCI
180	select IOMMU_SUPPORT		if PCI
181	select MODULES_USE_ELF_RELA
182	select NEED_DMA_MAP_STATE	if PCI
183	select NEED_SG_DMA_LENGTH	if PCI
184	select OLD_SIGACTION
185	select OLD_SIGSUSPEND3
186	select PCI_DOMAINS		if PCI
187	select PCI_MSI			if PCI
188	select SPARSE_IRQ
189	select SYSCTL_EXCEPTION_TRACE
190	select THREAD_INFO_IN_TASK
191	select TTY
192	select VIRT_CPU_ACCOUNTING
193	select ARCH_HAS_SCALED_CPUTIME
194	select HAVE_NMI
195	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
196	select SWIOTLB
197	select GENERIC_ALLOCATOR
198	imply IMA_SECURE_AND_OR_TRUSTED_BOOT
199
200
201config SCHED_OMIT_FRAME_POINTER
202	def_bool y
203
204config PGTABLE_LEVELS
205	int
206	default 5
207
208source "kernel/livepatch/Kconfig"
209
210menu "Processor type and features"
211
212config HAVE_MARCH_Z900_FEATURES
213	def_bool n
214
215config HAVE_MARCH_Z990_FEATURES
216	def_bool n
217	select HAVE_MARCH_Z900_FEATURES
218
219config HAVE_MARCH_Z9_109_FEATURES
220	def_bool n
221	select HAVE_MARCH_Z990_FEATURES
222
223config HAVE_MARCH_Z10_FEATURES
224	def_bool n
225	select HAVE_MARCH_Z9_109_FEATURES
226
227config HAVE_MARCH_Z196_FEATURES
228	def_bool n
229	select HAVE_MARCH_Z10_FEATURES
230
231config HAVE_MARCH_ZEC12_FEATURES
232	def_bool n
233	select HAVE_MARCH_Z196_FEATURES
234
235config HAVE_MARCH_Z13_FEATURES
236	def_bool n
237	select HAVE_MARCH_ZEC12_FEATURES
238
239config HAVE_MARCH_Z14_FEATURES
240	def_bool n
241	select HAVE_MARCH_Z13_FEATURES
242
243config HAVE_MARCH_Z15_FEATURES
244	def_bool n
245	select HAVE_MARCH_Z14_FEATURES
246
247choice
248	prompt "Processor type"
249	default MARCH_Z196
250
251config MARCH_Z900
252	bool "IBM zSeries model z800 and z900"
253	select HAVE_MARCH_Z900_FEATURES
254	depends on $(cc-option,-march=z900)
255	help
256	  Select this to enable optimizations for model z800/z900 (2064 and
257	  2066 series). This will enable some optimizations that are not
258	  available on older ESA/390 (31 Bit) only CPUs.
259
260config MARCH_Z990
261	bool "IBM zSeries model z890 and z990"
262	select HAVE_MARCH_Z990_FEATURES
263	depends on $(cc-option,-march=z990)
264	help
265	  Select this to enable optimizations for model z890/z990 (2084 and
266	  2086 series). The kernel will be slightly faster but will not work
267	  on older machines.
268
269config MARCH_Z9_109
270	bool "IBM System z9"
271	select HAVE_MARCH_Z9_109_FEATURES
272	depends on $(cc-option,-march=z9-109)
273	help
274	  Select this to enable optimizations for IBM System z9 (2094 and
275	  2096 series). The kernel will be slightly faster but will not work
276	  on older machines.
277
278config MARCH_Z10
279	bool "IBM System z10"
280	select HAVE_MARCH_Z10_FEATURES
281	depends on $(cc-option,-march=z10)
282	help
283	  Select this to enable optimizations for IBM System z10 (2097 and
284	  2098 series). The kernel will be slightly faster but will not work
285	  on older machines.
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
332endchoice
333
334config MARCH_Z900_TUNE
335	def_bool TUNE_Z900 || MARCH_Z900 && TUNE_DEFAULT
336
337config MARCH_Z990_TUNE
338	def_bool TUNE_Z990 || MARCH_Z990 && TUNE_DEFAULT
339
340config MARCH_Z9_109_TUNE
341	def_bool TUNE_Z9_109 || MARCH_Z9_109 && TUNE_DEFAULT
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
361choice
362	prompt "Tune code generation"
363	default TUNE_DEFAULT
364	help
365	  Cause the compiler to tune (-mtune) the generated code for a machine.
366	  This will make the code run faster on the selected machine but
367	  somewhat slower on other machines.
368	  This option only changes how the compiler emits instructions, not the
369	  selection of instructions itself, so the resulting kernel will run on
370	  all other machines.
371
372config TUNE_DEFAULT
373	bool "Default"
374	help
375	  Tune the generated code for the target processor for which the kernel
376	  will be compiled.
377
378config TUNE_Z900
379	bool "IBM zSeries model z800 and z900"
380	depends on $(cc-option,-mtune=z900)
381
382config TUNE_Z990
383	bool "IBM zSeries model z890 and z990"
384	depends on $(cc-option,-mtune=z990)
385
386config TUNE_Z9_109
387	bool "IBM System z9"
388	depends on $(cc-option,-mtune=z9-109)
389
390config TUNE_Z10
391	bool "IBM System z10"
392	depends on $(cc-option,-mtune=z10)
393
394config TUNE_Z196
395	bool "IBM zEnterprise 114 and 196"
396	depends on $(cc-option,-mtune=z196)
397
398config TUNE_ZEC12
399	bool "IBM zBC12 and zEC12"
400	depends on $(cc-option,-mtune=zEC12)
401
402config TUNE_Z13
403	bool "IBM z13s and z13"
404	depends on $(cc-option,-mtune=z13)
405
406config TUNE_Z14
407	bool "IBM z14 ZR1 and z14"
408	depends on $(cc-option,-mtune=z14)
409
410config TUNE_Z15
411	bool "IBM z15"
412	depends on $(cc-option,-mtune=z15)
413
414endchoice
415
416config 64BIT
417	def_bool y
418
419config COMPAT
420	def_bool y
421	prompt "Kernel support for 31 bit emulation"
422	select COMPAT_BINFMT_ELF if BINFMT_ELF
423	select ARCH_WANT_OLD_COMPAT_IPC
424	select COMPAT_OLD_SIGACTION
425	select HAVE_UID16
426	depends on MULTIUSER
427	help
428	  Select this option if you want to enable your system kernel to
429	  handle system-calls from ELF binaries for 31 bit ESA.  This option
430	  (and some other stuff like libraries and such) is needed for
431	  executing 31 bit applications.  It is safe to say "Y".
432
433config SYSVIPC_COMPAT
434	def_bool y if COMPAT && SYSVIPC
435
436config SMP
437	def_bool y
438
439config NR_CPUS
440	int "Maximum number of CPUs (2-512)"
441	range 2 512
442	default "64"
443	help
444	  This allows you to specify the maximum number of CPUs which this
445	  kernel will support. The maximum supported value is 512 and the
446	  minimum value which makes sense is 2.
447
448	  This is purely to save memory - each supported CPU adds
449	  approximately sixteen kilobytes to the kernel image.
450
451config HOTPLUG_CPU
452	def_bool y
453
454config NUMA
455	bool "NUMA support"
456	depends on SCHED_TOPOLOGY
457	default n
458	help
459	  Enable NUMA support
460
461	  This option adds NUMA support to the kernel.
462
463config NODES_SHIFT
464	int
465	default "1"
466
467config SCHED_SMT
468	def_bool n
469
470config SCHED_MC
471	def_bool n
472
473config SCHED_BOOK
474	def_bool n
475
476config SCHED_DRAWER
477	def_bool n
478
479config SCHED_TOPOLOGY
480	def_bool y
481	prompt "Topology scheduler support"
482	select SCHED_SMT
483	select SCHED_MC
484	select SCHED_BOOK
485	select SCHED_DRAWER
486	help
487	  Topology scheduler support improves the CPU scheduler's decision
488	  making when dealing with machines that have multi-threading,
489	  multiple cores or multiple books.
490
491source "kernel/Kconfig.hz"
492
493config KEXEC
494	def_bool y
495	select KEXEC_CORE
496
497config KEXEC_FILE
498	bool "kexec file based system call"
499	select KEXEC_CORE
500	select BUILD_BIN2C
501	depends on CRYPTO
502	depends on CRYPTO_SHA256
503	depends on CRYPTO_SHA256_S390
504	help
505	  Enable the kexec file based system call. In contrast to the normal
506	  kexec system call this system call takes file descriptors for the
507	  kernel and initramfs as arguments.
508
509config ARCH_HAS_KEXEC_PURGATORY
510	def_bool y
511	depends on KEXEC_FILE
512
513config KEXEC_SIG
514	bool "Verify kernel signature during kexec_file_load() syscall"
515	depends on KEXEC_FILE && MODULE_SIG_FORMAT
516	help
517	  This option makes kernel signature verification mandatory for
518	  the kexec_file_load() syscall.
519
520	  In addition to that option, you need to enable signature
521	  verification for the corresponding kernel image type being
522	  loaded in order for this to work.
523
524config ARCH_RANDOM
525	def_bool y
526	prompt "s390 architectural random number generation API"
527	help
528	  Enable the s390 architectural random number generation API
529	  to provide random data for all consumers within the Linux
530	  kernel.
531
532	  When enabled the arch_random_* functions declared in linux/random.h
533	  are implemented. The implementation is based on the s390 CPACF
534	  instruction subfunction TRNG which provides a real true random
535	  number generator.
536
537	  If unsure, say Y.
538
539config KERNEL_NOBP
540	def_bool n
541	prompt "Enable modified branch prediction for the kernel by default"
542	help
543	  If this option is selected the kernel will switch to a modified
544	  branch prediction mode if the firmware interface is available.
545	  The modified branch prediction mode improves the behaviour in
546	  regard to speculative execution.
547
548	  With the option enabled the kernel parameter "nobp=0" or "nospec"
549	  can be used to run the kernel in the normal branch prediction mode.
550
551	  With the option disabled the modified branch prediction mode is
552	  enabled with the "nobp=1" kernel parameter.
553
554	  If unsure, say N.
555
556config EXPOLINE
557	def_bool n
558	prompt "Avoid speculative indirect branches in the kernel"
559	help
560	  Compile the kernel with the expoline compiler options to guard
561	  against kernel-to-user data leaks by avoiding speculative indirect
562	  branches.
563	  Requires a compiler with -mindirect-branch=thunk support for full
564	  protection. The kernel may run slower.
565
566	  If unsure, say N.
567
568choice
569	prompt "Expoline default"
570	depends on EXPOLINE
571	default EXPOLINE_FULL
572
573config EXPOLINE_OFF
574	bool "spectre_v2=off"
575
576config EXPOLINE_AUTO
577	bool "spectre_v2=auto"
578
579config EXPOLINE_FULL
580	bool "spectre_v2=on"
581
582endchoice
583
584config RELOCATABLE
585	bool "Build a relocatable kernel"
586	select MODULE_REL_CRCS if MODVERSIONS
587	default y
588	help
589	  This builds a kernel image that retains relocation information
590	  so it can be loaded at an arbitrary address.
591	  The kernel is linked as a position-independent executable (PIE)
592	  and contains dynamic relocations which are processed early in the
593	  bootup process.
594	  The relocations make the kernel image about 15% larger (compressed
595	  10%), but are discarded at runtime.
596
597config RANDOMIZE_BASE
598	bool "Randomize the address of the kernel image (KASLR)"
599	depends on RELOCATABLE
600	default y
601	help
602	  In support of Kernel Address Space Layout Randomization (KASLR),
603	  this randomizes the address at which the kernel image is loaded,
604	  as a security feature that deters exploit attempts relying on
605	  knowledge of the location of kernel internals.
606
607endmenu
608
609menu "Memory setup"
610
611config ARCH_SPARSEMEM_ENABLE
612	def_bool y
613	select SPARSEMEM_VMEMMAP_ENABLE
614	select SPARSEMEM_VMEMMAP
615
616config ARCH_SPARSEMEM_DEFAULT
617	def_bool y
618
619config ARCH_ENABLE_MEMORY_HOTPLUG
620	def_bool y if SPARSEMEM
621
622config ARCH_ENABLE_MEMORY_HOTREMOVE
623	def_bool y
624
625config ARCH_ENABLE_SPLIT_PMD_PTLOCK
626	def_bool y
627
628config FORCE_MAX_ZONEORDER
629	int
630	default "9"
631
632config MAX_PHYSMEM_BITS
633	int "Maximum size of supported physical memory in bits (42-53)"
634	range 42 53
635	default "46"
636	help
637	  This option specifies the maximum supported size of physical memory
638	  in bits. Supported is any size between 2^42 (4TB) and 2^53 (8PB).
639	  Increasing the number of bits also increases the kernel image size.
640	  By default 46 bits (64TB) are supported.
641
642config PACK_STACK
643	def_bool y
644	prompt "Pack kernel stack"
645	help
646	  This option enables the compiler option -mkernel-backchain if it
647	  is available. If the option is available the compiler supports
648	  the new stack layout which dramatically reduces the minimum stack
649	  frame size. With an old compiler a non-leaf function needs a
650	  minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
651	  -mkernel-backchain the minimum size drops to 16 byte on 31 bit
652	  and 24 byte on 64 bit.
653
654	  Say Y if you are unsure.
655
656config CHECK_STACK
657	def_bool y
658	depends on !VMAP_STACK
659	prompt "Detect kernel stack overflow"
660	help
661	  This option enables the compiler option -mstack-guard and
662	  -mstack-size if they are available. If the compiler supports them
663	  it will emit additional code to each function prolog to trigger
664	  an illegal operation if the kernel stack is about to overflow.
665
666	  Say N if you are unsure.
667
668config STACK_GUARD
669	int "Size of the guard area (128-1024)"
670	range 128 1024
671	depends on CHECK_STACK
672	default "256"
673	help
674	  This allows you to specify the size of the guard area at the lower
675	  end of the kernel stack. If the kernel stack points into the guard
676	  area on function entry an illegal operation is triggered. The size
677	  needs to be a power of 2. Please keep in mind that the size of an
678	  interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
679	  The minimum size for the stack guard should be 256 for 31 bit and
680	  512 for 64 bit.
681
682config WARN_DYNAMIC_STACK
683	def_bool n
684	prompt "Emit compiler warnings for function with dynamic stack usage"
685	help
686	  This option enables the compiler option -mwarn-dynamicstack. If the
687	  compiler supports this options generates warnings for functions
688	  that dynamically allocate stack space using alloca.
689
690	  Say N if you are unsure.
691
692endmenu
693
694menu "I/O subsystem"
695
696config QDIO
697	def_tristate y
698	prompt "QDIO support"
699	---help---
700	  This driver provides the Queued Direct I/O base support for
701	  IBM System z.
702
703	  To compile this driver as a module, choose M here: the
704	  module will be called qdio.
705
706	  If unsure, say Y.
707
708if PCI
709
710config PCI_NR_FUNCTIONS
711	int "Maximum number of PCI functions (1-4096)"
712	range 1 4096
713	default "128"
714	help
715	  This allows you to specify the maximum number of PCI functions which
716	  this kernel will support.
717
718endif # PCI
719
720config HAS_IOMEM
721	def_bool PCI
722
723config CHSC_SCH
724	def_tristate m
725	prompt "Support for CHSC subchannels"
726	help
727	  This driver allows usage of CHSC subchannels. A CHSC subchannel
728	  is usually present on LPAR only.
729	  The driver creates a device /dev/chsc, which may be used to
730	  obtain I/O configuration information about the machine and
731	  to issue asynchronous chsc commands (DANGEROUS).
732	  You will usually only want to use this interface on a special
733	  LPAR designated for system management.
734
735	  To compile this driver as a module, choose M here: the
736	  module will be called chsc_sch.
737
738	  If unsure, say N.
739
740config SCM_BUS
741	def_bool y
742	prompt "SCM bus driver"
743	help
744	  Bus driver for Storage Class Memory.
745
746config EADM_SCH
747	def_tristate m
748	prompt "Support for EADM subchannels"
749	depends on SCM_BUS
750	help
751	  This driver allows usage of EADM subchannels. EADM subchannels act
752	  as a communication vehicle for SCM increments.
753
754	  To compile this driver as a module, choose M here: the
755	  module will be called eadm_sch.
756
757config VFIO_CCW
758	def_tristate n
759	prompt "Support for VFIO-CCW subchannels"
760	depends on S390_CCW_IOMMU && VFIO_MDEV
761	help
762	  This driver allows usage of I/O subchannels via VFIO-CCW.
763
764	  To compile this driver as a module, choose M here: the
765	  module will be called vfio_ccw.
766
767config VFIO_AP
768	def_tristate n
769	prompt "VFIO support for AP devices"
770	depends on S390_AP_IOMMU && VFIO_MDEV_DEVICE && KVM
771	help
772		This driver grants access to Adjunct Processor (AP) devices
773		via the VFIO mediated device interface.
774
775		To compile this driver as a module, choose M here: the module
776		will be called vfio_ap.
777
778endmenu
779
780menu "Dump support"
781
782config CRASH_DUMP
783	bool "kernel crash dumps"
784	select KEXEC
785	help
786	  Generate crash dump after being started by kexec.
787	  Crash dump kernels are loaded in the main kernel with kexec-tools
788	  into a specially reserved region and then later executed after
789	  a crash by kdump/kexec.
790	  Refer to <file:Documentation/s390/zfcpdump.rst> for more details on this.
791	  This option also enables s390 zfcpdump.
792	  See also <file:Documentation/s390/zfcpdump.rst>
793
794endmenu
795
796config SECCOMP
797	def_bool y
798	prompt "Enable seccomp to safely compute untrusted bytecode"
799	depends on PROC_FS
800	help
801	  This kernel feature is useful for number crunching applications
802	  that may need to compute untrusted bytecode during their
803	  execution. By using pipes or other transports made available to
804	  the process as file descriptors supporting the read/write
805	  syscalls, it's possible to isolate those applications in
806	  their own address space using seccomp. Once seccomp is
807	  enabled via /proc/<pid>/seccomp, it cannot be disabled
808	  and the task is only allowed to execute a few safe syscalls
809	  defined by each seccomp mode.
810
811	  If unsure, say Y.
812
813config CCW
814	def_bool y
815
816config HAVE_PNETID
817	tristate
818	default (SMC || CCWGROUP)
819
820menu "Virtualization"
821
822config PROTECTED_VIRTUALIZATION_GUEST
823	def_bool n
824	prompt "Protected virtualization guest support"
825	help
826	  Select this option, if you want to be able to run this
827	  kernel as a protected virtualization KVM guest.
828	  Protected virtualization capable machines have a mini hypervisor
829	  located at machine level (an ultravisor). With help of the
830	  Ultravisor, KVM will be able to run "protected" VMs, special
831	  VMs whose memory and management data are unavailable to KVM.
832
833config PFAULT
834	def_bool y
835	prompt "Pseudo page fault support"
836	help
837	  Select this option, if you want to use PFAULT pseudo page fault
838	  handling under VM. If running native or in LPAR, this option
839	  has no effect. If your VM does not support PFAULT, PAGEEX
840	  pseudo page fault handling will be used.
841	  Note that VM 4.2 supports PFAULT but has a bug in its
842	  implementation that causes some problems.
843	  Everybody who wants to run Linux under VM != VM4.2 should select
844	  this option.
845
846config CMM
847	def_tristate n
848	prompt "Cooperative memory management"
849	help
850	  Select this option, if you want to enable the kernel interface
851	  to reduce the memory size of the system. This is accomplished
852	  by allocating pages of memory and put them "on hold". This only
853	  makes sense for a system running under VM where the unused pages
854	  will be reused by VM for other guest systems. The interface
855	  allows an external monitor to balance memory of many systems.
856	  Everybody who wants to run Linux under VM should select this
857	  option.
858
859config CMM_IUCV
860	def_bool y
861	prompt "IUCV special message interface to cooperative memory management"
862	depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
863	help
864	  Select this option to enable the special message interface to
865	  the cooperative memory management.
866
867config APPLDATA_BASE
868	def_bool n
869	prompt "Linux - VM Monitor Stream, base infrastructure"
870	depends on PROC_FS
871	help
872	  This provides a kernel interface for creating and updating z/VM APPLDATA
873	  monitor records. The monitor records are updated at certain time
874	  intervals, once the timer is started.
875	  Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
876	  i.e. enables or disables monitoring on the Linux side.
877	  A custom interval value (in seconds) can be written to
878	  /proc/appldata/interval.
879
880	  Defaults are 60 seconds interval and timer off.
881	  The /proc entries can also be read from, showing the current settings.
882
883config APPLDATA_MEM
884	def_tristate m
885	prompt "Monitor memory management statistics"
886	depends on APPLDATA_BASE && VM_EVENT_COUNTERS
887	help
888	  This provides memory management related data to the Linux - VM Monitor
889	  Stream, like paging/swapping rate, memory utilisation, etc.
890	  Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
891	  APPLDATA monitor record, i.e. enables or disables monitoring this record
892	  on the z/VM side.
893
894	  Default is disabled.
895	  The /proc entry can also be read from, showing the current settings.
896
897	  This can also be compiled as a module, which will be called
898	  appldata_mem.o.
899
900config APPLDATA_OS
901	def_tristate m
902	prompt "Monitor OS statistics"
903	depends on APPLDATA_BASE
904	help
905	  This provides OS related data to the Linux - VM Monitor Stream, like
906	  CPU utilisation, etc.
907	  Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
908	  APPLDATA monitor record, i.e. enables or disables monitoring this record
909	  on the z/VM side.
910
911	  Default is disabled.
912	  This can also be compiled as a module, which will be called
913	  appldata_os.o.
914
915config APPLDATA_NET_SUM
916	def_tristate m
917	prompt "Monitor overall network statistics"
918	depends on APPLDATA_BASE && NET
919	help
920	  This provides network related data to the Linux - VM Monitor Stream,
921	  currently there is only a total sum of network I/O statistics, no
922	  per-interface data.
923	  Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
924	  APPLDATA monitor record, i.e. enables or disables monitoring this record
925	  on the z/VM side.
926
927	  Default is disabled.
928	  This can also be compiled as a module, which will be called
929	  appldata_net_sum.o.
930
931config S390_HYPFS_FS
932	def_bool y
933	prompt "s390 hypervisor file system support"
934	select SYS_HYPERVISOR
935	help
936	  This is a virtual file system intended to provide accounting
937	  information in an s390 hypervisor environment.
938
939source "arch/s390/kvm/Kconfig"
940
941config S390_GUEST
942	def_bool y
943	prompt "s390 support for virtio devices"
944	select TTY
945	select VIRTUALIZATION
946	select VIRTIO
947	help
948	  Enabling this option adds support for virtio based paravirtual device
949	  drivers on s390.
950
951	  Select this option if you want to run the kernel as a guest under
952	  the KVM hypervisor.
953
954endmenu
955
956menu "Selftests"
957
958config S390_UNWIND_SELFTEST
959	def_tristate n
960	prompt "Test unwind functions"
961	help
962	  This option enables s390 specific stack unwinder testing kernel
963	  module. This option is not useful for distributions or general
964	  kernels, but only for kernel developers working on architecture code.
965
966	  Say N if you are unsure.
967
968endmenu
969