xref: /openbmc/linux/arch/s390/Kconfig (revision 05911c5d)
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 0x18000000000000
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 ARCH_32BIT_USTAT_F_TINODE
59	select ARCH_BINFMT_ELF_STATE
60	select ARCH_ENABLE_MEMORY_HOTPLUG if SPARSEMEM
61	select ARCH_ENABLE_MEMORY_HOTREMOVE
62	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
63	select ARCH_HAS_DEBUG_VM_PGTABLE
64	select ARCH_HAS_DEBUG_WX
65	select ARCH_HAS_DEVMEM_IS_ALLOWED
66	select ARCH_HAS_ELF_RANDOMIZE
67	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
68	select ARCH_HAS_FORTIFY_SOURCE
69	select ARCH_HAS_GCOV_PROFILE_ALL
70	select ARCH_HAS_GIGANTIC_PAGE
71	select ARCH_HAS_KCOV
72	select ARCH_HAS_MEM_ENCRYPT
73	select ARCH_HAS_PTE_SPECIAL
74	select ARCH_HAS_SCALED_CPUTIME
75	select ARCH_HAS_SET_MEMORY
76	select ARCH_HAS_STRICT_KERNEL_RWX
77	select ARCH_HAS_STRICT_MODULE_RWX
78	select ARCH_HAS_SYSCALL_WRAPPER
79	select ARCH_HAS_UBSAN_SANITIZE_ALL
80	select ARCH_HAS_VDSO_DATA
81	select ARCH_HAVE_NMI_SAFE_CMPXCHG
82	select ARCH_INLINE_READ_LOCK
83	select ARCH_INLINE_READ_LOCK_BH
84	select ARCH_INLINE_READ_LOCK_IRQ
85	select ARCH_INLINE_READ_LOCK_IRQSAVE
86	select ARCH_INLINE_READ_TRYLOCK
87	select ARCH_INLINE_READ_UNLOCK
88	select ARCH_INLINE_READ_UNLOCK_BH
89	select ARCH_INLINE_READ_UNLOCK_IRQ
90	select ARCH_INLINE_READ_UNLOCK_IRQRESTORE
91	select ARCH_INLINE_SPIN_LOCK
92	select ARCH_INLINE_SPIN_LOCK_BH
93	select ARCH_INLINE_SPIN_LOCK_IRQ
94	select ARCH_INLINE_SPIN_LOCK_IRQSAVE
95	select ARCH_INLINE_SPIN_TRYLOCK
96	select ARCH_INLINE_SPIN_TRYLOCK_BH
97	select ARCH_INLINE_SPIN_UNLOCK
98	select ARCH_INLINE_SPIN_UNLOCK_BH
99	select ARCH_INLINE_SPIN_UNLOCK_IRQ
100	select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE
101	select ARCH_INLINE_WRITE_LOCK
102	select ARCH_INLINE_WRITE_LOCK_BH
103	select ARCH_INLINE_WRITE_LOCK_IRQ
104	select ARCH_INLINE_WRITE_LOCK_IRQSAVE
105	select ARCH_INLINE_WRITE_TRYLOCK
106	select ARCH_INLINE_WRITE_UNLOCK
107	select ARCH_INLINE_WRITE_UNLOCK_BH
108	select ARCH_INLINE_WRITE_UNLOCK_IRQ
109	select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
110	select ARCH_STACKWALK
111	select ARCH_SUPPORTS_ATOMIC_RMW
112	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
113	select ARCH_SUPPORTS_NUMA_BALANCING
114	select ARCH_USE_BUILTIN_BSWAP
115	select ARCH_USE_CMPXCHG_LOCKREF
116	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
117	select ARCH_WANT_DEFAULT_BPF_JIT
118	select ARCH_WANT_IPC_PARSE_VERSION
119	select BUILDTIME_TABLE_SORT
120	select CLONE_BACKWARDS2
121	select CPU_NO_EFFICIENT_FFS if !HAVE_MARCH_Z9_109_FEATURES
122	select DMA_OPS if PCI
123	select DYNAMIC_FTRACE if FUNCTION_TRACER
124	select GENERIC_ALLOCATOR
125	select GENERIC_CPU_AUTOPROBE
126	select GENERIC_CPU_VULNERABILITIES
127	select GENERIC_ENTRY
128	select GENERIC_FIND_FIRST_BIT
129	select GENERIC_GETTIMEOFDAY
130	select GENERIC_PTDUMP
131	select GENERIC_SMP_IDLE_THREAD
132	select GENERIC_TIME_VSYSCALL
133	select GENERIC_VDSO_TIME_NS
134	select HAVE_ALIGNED_STRUCT_PAGE if SLUB
135	select HAVE_ARCH_AUDITSYSCALL
136	select HAVE_ARCH_JUMP_LABEL
137	select HAVE_ARCH_JUMP_LABEL_RELATIVE
138	select HAVE_ARCH_KASAN
139	select HAVE_ARCH_KASAN_VMALLOC
140	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
141	select HAVE_ARCH_SECCOMP_FILTER
142	select HAVE_ARCH_SOFT_DIRTY
143	select HAVE_ARCH_TRACEHOOK
144	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
145	select HAVE_ARCH_VMAP_STACK
146	select HAVE_ASM_MODVERSIONS
147	select HAVE_CMPXCHG_DOUBLE
148	select HAVE_CMPXCHG_LOCAL
149	select HAVE_DEBUG_KMEMLEAK
150	select HAVE_DMA_CONTIGUOUS
151	select HAVE_DYNAMIC_FTRACE
152	select HAVE_DYNAMIC_FTRACE_WITH_REGS
153	select HAVE_EBPF_JIT if PACK_STACK && HAVE_MARCH_Z196_FEATURES
154	select HAVE_EFFICIENT_UNALIGNED_ACCESS
155	select HAVE_FAST_GUP
156	select HAVE_FENTRY
157	select HAVE_FTRACE_MCOUNT_RECORD
158	select HAVE_FUNCTION_ERROR_INJECTION
159	select HAVE_FUNCTION_GRAPH_TRACER
160	select HAVE_FUNCTION_TRACER
161	select HAVE_FUTEX_CMPXCHG if FUTEX
162	select HAVE_GCC_PLUGINS
163	select HAVE_GENERIC_VDSO
164	select HAVE_IRQ_EXIT_ON_IRQ_STACK
165	select HAVE_KERNEL_BZIP2
166	select HAVE_KERNEL_GZIP
167	select HAVE_KERNEL_LZ4
168	select HAVE_KERNEL_LZMA
169	select HAVE_KERNEL_LZO
170	select HAVE_KERNEL_UNCOMPRESSED
171	select HAVE_KERNEL_XZ
172	select HAVE_KPROBES
173	select HAVE_KPROBES_ON_FTRACE
174	select HAVE_KRETPROBES
175	select HAVE_KVM
176	select HAVE_LIVEPATCH
177	select HAVE_MEMBLOCK_PHYS_MAP
178	select HAVE_MOD_ARCH_SPECIFIC
179	select HAVE_NMI
180	select HAVE_NOP_MCOUNT
181	select HAVE_PCI
182	select HAVE_PERF_EVENTS
183	select HAVE_PERF_REGS
184	select HAVE_PERF_USER_STACK_DUMP
185	select HAVE_REGS_AND_STACK_ACCESS_API
186	select HAVE_RELIABLE_STACKTRACE
187	select HAVE_RSEQ
188	select HAVE_SOFTIRQ_ON_OWN_STACK
189	select HAVE_SYSCALL_TRACEPOINTS
190	select HAVE_VIRT_CPU_ACCOUNTING
191	select HAVE_VIRT_CPU_ACCOUNTING_IDLE
192	select IOMMU_HELPER		if PCI
193	select IOMMU_SUPPORT		if PCI
194	select MMU_GATHER_NO_GATHER
195	select MMU_GATHER_RCU_TABLE_FREE
196	select MODULES_USE_ELF_RELA
197	select NEED_DMA_MAP_STATE	if PCI
198	select NEED_SG_DMA_LENGTH	if PCI
199	select OLD_SIGACTION
200	select OLD_SIGSUSPEND3
201	select PCI_DOMAINS		if PCI
202	select PCI_MSI			if PCI
203	select PCI_MSI_ARCH_FALLBACKS	if PCI_MSI
204	select SPARSE_IRQ
205	select SWIOTLB
206	select SYSCTL_EXCEPTION_TRACE
207	select THREAD_INFO_IN_TASK
208	select TTY
209	select VIRT_CPU_ACCOUNTING
210	select ZONE_DMA
211	# Note: keep the above list sorted alphabetically
212
213config SCHED_OMIT_FRAME_POINTER
214	def_bool y
215
216config PGTABLE_LEVELS
217	int
218	default 5
219
220source "kernel/livepatch/Kconfig"
221
222menu "Processor type and features"
223
224config HAVE_MARCH_Z900_FEATURES
225	def_bool n
226
227config HAVE_MARCH_Z990_FEATURES
228	def_bool n
229	select HAVE_MARCH_Z900_FEATURES
230
231config HAVE_MARCH_Z9_109_FEATURES
232	def_bool n
233	select HAVE_MARCH_Z990_FEATURES
234
235config HAVE_MARCH_Z10_FEATURES
236	def_bool n
237	select HAVE_MARCH_Z9_109_FEATURES
238
239config HAVE_MARCH_Z196_FEATURES
240	def_bool n
241	select HAVE_MARCH_Z10_FEATURES
242
243config HAVE_MARCH_ZEC12_FEATURES
244	def_bool n
245	select HAVE_MARCH_Z196_FEATURES
246
247config HAVE_MARCH_Z13_FEATURES
248	def_bool n
249	select HAVE_MARCH_ZEC12_FEATURES
250
251config HAVE_MARCH_Z14_FEATURES
252	def_bool n
253	select HAVE_MARCH_Z13_FEATURES
254
255config HAVE_MARCH_Z15_FEATURES
256	def_bool n
257	select HAVE_MARCH_Z14_FEATURES
258
259choice
260	prompt "Processor type"
261	default MARCH_Z196
262
263config MARCH_Z900
264	bool "IBM zSeries model z800 and z900"
265	select HAVE_MARCH_Z900_FEATURES
266	depends on $(cc-option,-march=z900)
267	help
268	  Select this to enable optimizations for model z800/z900 (2064 and
269	  2066 series). This will enable some optimizations that are not
270	  available on older ESA/390 (31 Bit) only CPUs.
271
272config MARCH_Z990
273	bool "IBM zSeries model z890 and z990"
274	select HAVE_MARCH_Z990_FEATURES
275	depends on $(cc-option,-march=z990)
276	help
277	  Select this to enable optimizations for model z890/z990 (2084 and
278	  2086 series). The kernel will be slightly faster but will not work
279	  on older machines.
280
281config MARCH_Z9_109
282	bool "IBM System z9"
283	select HAVE_MARCH_Z9_109_FEATURES
284	depends on $(cc-option,-march=z9-109)
285	help
286	  Select this to enable optimizations for IBM System z9 (2094 and
287	  2096 series). The kernel will be slightly faster but will not work
288	  on older machines.
289
290config MARCH_Z10
291	bool "IBM System z10"
292	select HAVE_MARCH_Z10_FEATURES
293	depends on $(cc-option,-march=z10)
294	help
295	  Select this to enable optimizations for IBM System z10 (2097 and
296	  2098 series). The kernel will be slightly faster but will not work
297	  on older machines.
298
299config MARCH_Z196
300	bool "IBM zEnterprise 114 and 196"
301	select HAVE_MARCH_Z196_FEATURES
302	depends on $(cc-option,-march=z196)
303	help
304	  Select this to enable optimizations for IBM zEnterprise 114 and 196
305	  (2818 and 2817 series). The kernel will be slightly faster but will
306	  not work on older machines.
307
308config MARCH_ZEC12
309	bool "IBM zBC12 and zEC12"
310	select HAVE_MARCH_ZEC12_FEATURES
311	depends on $(cc-option,-march=zEC12)
312	help
313	  Select this to enable optimizations for IBM zBC12 and zEC12 (2828 and
314	  2827 series). The kernel will be slightly faster but will not work on
315	  older machines.
316
317config MARCH_Z13
318	bool "IBM z13s and z13"
319	select HAVE_MARCH_Z13_FEATURES
320	depends on $(cc-option,-march=z13)
321	help
322	  Select this to enable optimizations for IBM z13s and z13 (2965 and
323	  2964 series). The kernel will be slightly faster but will not work on
324	  older machines.
325
326config MARCH_Z14
327	bool "IBM z14 ZR1 and z14"
328	select HAVE_MARCH_Z14_FEATURES
329	depends on $(cc-option,-march=z14)
330	help
331	  Select this to enable optimizations for IBM z14 ZR1 and z14 (3907
332	  and 3906 series). The kernel will be slightly faster but will not
333	  work on older machines.
334
335config MARCH_Z15
336	bool "IBM z15"
337	select HAVE_MARCH_Z15_FEATURES
338	depends on $(cc-option,-march=z15)
339	help
340	  Select this to enable optimizations for IBM z15 (8562
341	  and 8561 series). The kernel will be slightly faster but will not
342	  work on older machines.
343
344endchoice
345
346config MARCH_Z900_TUNE
347	def_bool TUNE_Z900 || MARCH_Z900 && TUNE_DEFAULT
348
349config MARCH_Z990_TUNE
350	def_bool TUNE_Z990 || MARCH_Z990 && TUNE_DEFAULT
351
352config MARCH_Z9_109_TUNE
353	def_bool TUNE_Z9_109 || MARCH_Z9_109 && TUNE_DEFAULT
354
355config MARCH_Z10_TUNE
356	def_bool TUNE_Z10 || MARCH_Z10 && TUNE_DEFAULT
357
358config MARCH_Z196_TUNE
359	def_bool TUNE_Z196 || MARCH_Z196 && TUNE_DEFAULT
360
361config MARCH_ZEC12_TUNE
362	def_bool TUNE_ZEC12 || MARCH_ZEC12 && TUNE_DEFAULT
363
364config MARCH_Z13_TUNE
365	def_bool TUNE_Z13 || MARCH_Z13 && TUNE_DEFAULT
366
367config MARCH_Z14_TUNE
368	def_bool TUNE_Z14 || MARCH_Z14 && TUNE_DEFAULT
369
370config MARCH_Z15_TUNE
371	def_bool TUNE_Z15 || MARCH_Z15 && TUNE_DEFAULT
372
373choice
374	prompt "Tune code generation"
375	default TUNE_DEFAULT
376	help
377	  Cause the compiler to tune (-mtune) the generated code for a machine.
378	  This will make the code run faster on the selected machine but
379	  somewhat slower on other machines.
380	  This option only changes how the compiler emits instructions, not the
381	  selection of instructions itself, so the resulting kernel will run on
382	  all other machines.
383
384config TUNE_DEFAULT
385	bool "Default"
386	help
387	  Tune the generated code for the target processor for which the kernel
388	  will be compiled.
389
390config TUNE_Z900
391	bool "IBM zSeries model z800 and z900"
392	depends on $(cc-option,-mtune=z900)
393
394config TUNE_Z990
395	bool "IBM zSeries model z890 and z990"
396	depends on $(cc-option,-mtune=z990)
397
398config TUNE_Z9_109
399	bool "IBM System z9"
400	depends on $(cc-option,-mtune=z9-109)
401
402config TUNE_Z10
403	bool "IBM System z10"
404	depends on $(cc-option,-mtune=z10)
405
406config TUNE_Z196
407	bool "IBM zEnterprise 114 and 196"
408	depends on $(cc-option,-mtune=z196)
409
410config TUNE_ZEC12
411	bool "IBM zBC12 and zEC12"
412	depends on $(cc-option,-mtune=zEC12)
413
414config TUNE_Z13
415	bool "IBM z13s and z13"
416	depends on $(cc-option,-mtune=z13)
417
418config TUNE_Z14
419	bool "IBM z14 ZR1 and z14"
420	depends on $(cc-option,-mtune=z14)
421
422config TUNE_Z15
423	bool "IBM z15"
424	depends on $(cc-option,-mtune=z15)
425
426endchoice
427
428config 64BIT
429	def_bool y
430
431config COMPAT
432	def_bool y
433	prompt "Kernel support for 31 bit emulation"
434	select ARCH_WANT_OLD_COMPAT_IPC
435	select COMPAT_OLD_SIGACTION
436	select HAVE_UID16
437	depends on MULTIUSER
438	help
439	  Select this option if you want to enable your system kernel to
440	  handle system-calls from ELF binaries for 31 bit ESA.  This option
441	  (and some other stuff like libraries and such) is needed for
442	  executing 31 bit applications.  It is safe to say "Y".
443
444config SYSVIPC_COMPAT
445	def_bool y if COMPAT && SYSVIPC
446
447config SMP
448	def_bool y
449
450config NR_CPUS
451	int "Maximum number of CPUs (2-512)"
452	range 2 512
453	default "64"
454	help
455	  This allows you to specify the maximum number of CPUs which this
456	  kernel will support. The maximum supported value is 512 and the
457	  minimum value which makes sense is 2.
458
459	  This is purely to save memory - each supported CPU adds
460	  approximately sixteen kilobytes to the kernel image.
461
462config HOTPLUG_CPU
463	def_bool y
464
465config NUMA
466	bool "NUMA support"
467	depends on SCHED_TOPOLOGY
468	default n
469	help
470	  Enable NUMA support
471
472	  This option adds NUMA support to the kernel.
473
474config NODES_SHIFT
475	int
476	depends on NUMA
477	default "1"
478
479config SCHED_SMT
480	def_bool n
481
482config SCHED_MC
483	def_bool n
484
485config SCHED_BOOK
486	def_bool n
487
488config SCHED_DRAWER
489	def_bool n
490
491config SCHED_TOPOLOGY
492	def_bool y
493	prompt "Topology scheduler support"
494	select SCHED_SMT
495	select SCHED_MC
496	select SCHED_BOOK
497	select SCHED_DRAWER
498	help
499	  Topology scheduler support improves the CPU scheduler's decision
500	  making when dealing with machines that have multi-threading,
501	  multiple cores or multiple books.
502
503source "kernel/Kconfig.hz"
504
505config KEXEC
506	def_bool y
507	select KEXEC_CORE
508
509config KEXEC_FILE
510	bool "kexec file based system call"
511	select KEXEC_CORE
512	select BUILD_BIN2C
513	depends on CRYPTO
514	depends on CRYPTO_SHA256
515	depends on CRYPTO_SHA256_S390
516	help
517	  Enable the kexec file based system call. In contrast to the normal
518	  kexec system call this system call takes file descriptors for the
519	  kernel and initramfs as arguments.
520
521config ARCH_HAS_KEXEC_PURGATORY
522	def_bool y
523	depends on KEXEC_FILE
524
525config KEXEC_SIG
526	bool "Verify kernel signature during kexec_file_load() syscall"
527	depends on KEXEC_FILE && MODULE_SIG_FORMAT
528	help
529	  This option makes kernel signature verification mandatory for
530	  the kexec_file_load() syscall.
531
532	  In addition to that option, you need to enable signature
533	  verification for the corresponding kernel image type being
534	  loaded in order for this to work.
535
536config ARCH_RANDOM
537	def_bool y
538	prompt "s390 architectural random number generation API"
539	help
540	  Enable the s390 architectural random number generation API
541	  to provide random data for all consumers within the Linux
542	  kernel.
543
544	  When enabled the arch_random_* functions declared in linux/random.h
545	  are implemented. The implementation is based on the s390 CPACF
546	  instruction subfunction TRNG which provides a real true random
547	  number generator.
548
549	  If unsure, say Y.
550
551config KERNEL_NOBP
552	def_bool n
553	prompt "Enable modified branch prediction for the kernel by default"
554	help
555	  If this option is selected the kernel will switch to a modified
556	  branch prediction mode if the firmware interface is available.
557	  The modified branch prediction mode improves the behaviour in
558	  regard to speculative execution.
559
560	  With the option enabled the kernel parameter "nobp=0" or "nospec"
561	  can be used to run the kernel in the normal branch prediction mode.
562
563	  With the option disabled the modified branch prediction mode is
564	  enabled with the "nobp=1" kernel parameter.
565
566	  If unsure, say N.
567
568config EXPOLINE
569	def_bool n
570	prompt "Avoid speculative indirect branches in the kernel"
571	help
572	  Compile the kernel with the expoline compiler options to guard
573	  against kernel-to-user data leaks by avoiding speculative indirect
574	  branches.
575	  Requires a compiler with -mindirect-branch=thunk support for full
576	  protection. The kernel may run slower.
577
578	  If unsure, say N.
579
580choice
581	prompt "Expoline default"
582	depends on EXPOLINE
583	default EXPOLINE_FULL
584
585config EXPOLINE_OFF
586	bool "spectre_v2=off"
587
588config EXPOLINE_AUTO
589	bool "spectre_v2=auto"
590
591config EXPOLINE_FULL
592	bool "spectre_v2=on"
593
594endchoice
595
596config RELOCATABLE
597	bool "Build a relocatable kernel"
598	select MODULE_REL_CRCS if MODVERSIONS
599	default y
600	help
601	  This builds a kernel image that retains relocation information
602	  so it can be loaded at an arbitrary address.
603	  The kernel is linked as a position-independent executable (PIE)
604	  and contains dynamic relocations which are processed early in the
605	  bootup process.
606	  The relocations make the kernel image about 15% larger (compressed
607	  10%), but are discarded at runtime.
608
609config RANDOMIZE_BASE
610	bool "Randomize the address of the kernel image (KASLR)"
611	depends on RELOCATABLE
612	default y
613	help
614	  In support of Kernel Address Space Layout Randomization (KASLR),
615	  this randomizes the address at which the kernel image is loaded,
616	  as a security feature that deters exploit attempts relying on
617	  knowledge of the location of kernel internals.
618
619endmenu
620
621menu "Memory setup"
622
623config ARCH_SPARSEMEM_ENABLE
624	def_bool y
625	select SPARSEMEM_VMEMMAP_ENABLE
626	select SPARSEMEM_VMEMMAP
627
628config ARCH_SPARSEMEM_DEFAULT
629	def_bool y
630
631config MAX_PHYSMEM_BITS
632	int "Maximum size of supported physical memory in bits (42-53)"
633	range 42 53
634	default "46"
635	help
636	  This option specifies the maximum supported size of physical memory
637	  in bits. Supported is any size between 2^42 (4TB) and 2^53 (8PB).
638	  Increasing the number of bits also increases the kernel image size.
639	  By default 46 bits (64TB) are supported.
640
641config PACK_STACK
642	def_bool y
643	prompt "Pack kernel stack"
644	help
645	  This option enables the compiler option -mkernel-backchain if it
646	  is available. If the option is available the compiler supports
647	  the new stack layout which dramatically reduces the minimum stack
648	  frame size. With an old compiler a non-leaf function needs a
649	  minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
650	  -mkernel-backchain the minimum size drops to 16 byte on 31 bit
651	  and 24 byte on 64 bit.
652
653	  Say Y if you are unsure.
654
655config CHECK_STACK
656	def_bool y
657	depends on !VMAP_STACK
658	prompt "Detect kernel stack overflow"
659	help
660	  This option enables the compiler option -mstack-guard and
661	  -mstack-size if they are available. If the compiler supports them
662	  it will emit additional code to each function prolog to trigger
663	  an illegal operation if the kernel stack is about to overflow.
664
665	  Say N if you are unsure.
666
667config STACK_GUARD
668	int "Size of the guard area (128-1024)"
669	range 128 1024
670	depends on CHECK_STACK
671	default "256"
672	help
673	  This allows you to specify the size of the guard area at the lower
674	  end of the kernel stack. If the kernel stack points into the guard
675	  area on function entry an illegal operation is triggered. The size
676	  needs to be a power of 2. Please keep in mind that the size of an
677	  interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
678	  The minimum size for the stack guard should be 256 for 31 bit and
679	  512 for 64 bit.
680
681config WARN_DYNAMIC_STACK
682	def_bool n
683	prompt "Emit compiler warnings for function with dynamic stack usage"
684	help
685	  This option enables the compiler option -mwarn-dynamicstack. If the
686	  compiler supports this options generates warnings for functions
687	  that dynamically allocate stack space using alloca.
688
689	  Say N if you are unsure.
690
691endmenu
692
693menu "I/O subsystem"
694
695config QDIO
696	def_tristate y
697	prompt "QDIO support"
698	help
699	  This driver provides the Queued Direct I/O base support for
700	  IBM System z.
701
702	  To compile this driver as a module, choose M here: the
703	  module will be called qdio.
704
705	  If unsure, say Y.
706
707if PCI
708
709config PCI_NR_FUNCTIONS
710	int "Maximum number of PCI functions (1-4096)"
711	range 1 4096
712	default "512"
713	help
714	  This allows you to specify the maximum number of PCI functions which
715	  this kernel will support.
716
717endif # PCI
718
719config HAS_IOMEM
720	def_bool PCI
721
722config CHSC_SCH
723	def_tristate m
724	prompt "Support for CHSC subchannels"
725	help
726	  This driver allows usage of CHSC subchannels. A CHSC subchannel
727	  is usually present on LPAR only.
728	  The driver creates a device /dev/chsc, which may be used to
729	  obtain I/O configuration information about the machine and
730	  to issue asynchronous chsc commands (DANGEROUS).
731	  You will usually only want to use this interface on a special
732	  LPAR designated for system management.
733
734	  To compile this driver as a module, choose M here: the
735	  module will be called chsc_sch.
736
737	  If unsure, say N.
738
739config SCM_BUS
740	def_bool y
741	prompt "SCM bus driver"
742	help
743	  Bus driver for Storage Class Memory.
744
745config EADM_SCH
746	def_tristate m
747	prompt "Support for EADM subchannels"
748	depends on SCM_BUS
749	help
750	  This driver allows usage of EADM subchannels. EADM subchannels act
751	  as a communication vehicle for SCM increments.
752
753	  To compile this driver as a module, choose M here: the
754	  module will be called eadm_sch.
755
756config VFIO_CCW
757	def_tristate n
758	prompt "Support for VFIO-CCW subchannels"
759	depends on S390_CCW_IOMMU && VFIO_MDEV
760	help
761	  This driver allows usage of I/O subchannels via VFIO-CCW.
762
763	  To compile this driver as a module, choose M here: the
764	  module will be called vfio_ccw.
765
766config VFIO_AP
767	def_tristate n
768	prompt "VFIO support for AP devices"
769	depends on S390_AP_IOMMU && VFIO_MDEV_DEVICE && KVM
770	depends on ZCRYPT
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 CCW
797	def_bool y
798
799config HAVE_PNETID
800	tristate
801	default (SMC || CCWGROUP)
802
803menu "Virtualization"
804
805config PROTECTED_VIRTUALIZATION_GUEST
806	def_bool n
807	prompt "Protected virtualization guest support"
808	select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
809	help
810	  Select this option, if you want to be able to run this
811	  kernel as a protected virtualization KVM guest.
812	  Protected virtualization capable machines have a mini hypervisor
813	  located at machine level (an ultravisor). With help of the
814	  Ultravisor, KVM will be able to run "protected" VMs, special
815	  VMs whose memory and management data are unavailable to KVM.
816
817config PFAULT
818	def_bool y
819	prompt "Pseudo page fault support"
820	help
821	  Select this option, if you want to use PFAULT pseudo page fault
822	  handling under VM. If running native or in LPAR, this option
823	  has no effect. If your VM does not support PFAULT, PAGEEX
824	  pseudo page fault handling will be used.
825	  Note that VM 4.2 supports PFAULT but has a bug in its
826	  implementation that causes some problems.
827	  Everybody who wants to run Linux under VM != VM4.2 should select
828	  this option.
829
830config CMM
831	def_tristate n
832	prompt "Cooperative memory management"
833	help
834	  Select this option, if you want to enable the kernel interface
835	  to reduce the memory size of the system. This is accomplished
836	  by allocating pages of memory and put them "on hold". This only
837	  makes sense for a system running under VM where the unused pages
838	  will be reused by VM for other guest systems. The interface
839	  allows an external monitor to balance memory of many systems.
840	  Everybody who wants to run Linux under VM should select this
841	  option.
842
843config CMM_IUCV
844	def_bool y
845	prompt "IUCV special message interface to cooperative memory management"
846	depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
847	help
848	  Select this option to enable the special message interface to
849	  the cooperative memory management.
850
851config APPLDATA_BASE
852	def_bool n
853	prompt "Linux - VM Monitor Stream, base infrastructure"
854	depends on PROC_FS
855	help
856	  This provides a kernel interface for creating and updating z/VM APPLDATA
857	  monitor records. The monitor records are updated at certain time
858	  intervals, once the timer is started.
859	  Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
860	  i.e. enables or disables monitoring on the Linux side.
861	  A custom interval value (in seconds) can be written to
862	  /proc/appldata/interval.
863
864	  Defaults are 60 seconds interval and timer off.
865	  The /proc entries can also be read from, showing the current settings.
866
867config APPLDATA_MEM
868	def_tristate m
869	prompt "Monitor memory management statistics"
870	depends on APPLDATA_BASE && VM_EVENT_COUNTERS
871	help
872	  This provides memory management related data to the Linux - VM Monitor
873	  Stream, like paging/swapping rate, memory utilisation, etc.
874	  Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
875	  APPLDATA monitor record, i.e. enables or disables monitoring this record
876	  on the z/VM side.
877
878	  Default is disabled.
879	  The /proc entry can also be read from, showing the current settings.
880
881	  This can also be compiled as a module, which will be called
882	  appldata_mem.o.
883
884config APPLDATA_OS
885	def_tristate m
886	prompt "Monitor OS statistics"
887	depends on APPLDATA_BASE
888	help
889	  This provides OS related data to the Linux - VM Monitor Stream, like
890	  CPU utilisation, etc.
891	  Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
892	  APPLDATA monitor record, i.e. enables or disables monitoring this record
893	  on the z/VM side.
894
895	  Default is disabled.
896	  This can also be compiled as a module, which will be called
897	  appldata_os.o.
898
899config APPLDATA_NET_SUM
900	def_tristate m
901	prompt "Monitor overall network statistics"
902	depends on APPLDATA_BASE && NET
903	help
904	  This provides network related data to the Linux - VM Monitor Stream,
905	  currently there is only a total sum of network I/O statistics, no
906	  per-interface data.
907	  Writing 1 or 0 to /proc/appldata/net_sum 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_net_sum.o.
914
915config S390_HYPFS_FS
916	def_bool y
917	prompt "s390 hypervisor file system support"
918	select SYS_HYPERVISOR
919	help
920	  This is a virtual file system intended to provide accounting
921	  information in an s390 hypervisor environment.
922
923source "arch/s390/kvm/Kconfig"
924
925config S390_GUEST
926	def_bool y
927	prompt "s390 support for virtio devices"
928	select TTY
929	select VIRTUALIZATION
930	select VIRTIO
931	help
932	  Enabling this option adds support for virtio based paravirtual device
933	  drivers on s390.
934
935	  Select this option if you want to run the kernel as a guest under
936	  the KVM hypervisor.
937
938endmenu
939
940menu "Selftests"
941
942config S390_UNWIND_SELFTEST
943	def_tristate n
944	prompt "Test unwind functions"
945	help
946	  This option enables s390 specific stack unwinder testing kernel
947	  module. This option is not useful for distributions or general
948	  kernels, but only for kernel developers working on architecture code.
949
950	  Say N if you are unsure.
951
952endmenu
953