xref: /openbmc/linux/arch/s390/Kconfig (revision b4a6aaea)
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_HUGETLBFS
114	select ARCH_SUPPORTS_NUMA_BALANCING
115	select ARCH_USE_BUILTIN_BSWAP
116	select ARCH_USE_CMPXCHG_LOCKREF
117	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
118	select ARCH_WANTS_NO_INSTR
119	select ARCH_WANT_DEFAULT_BPF_JIT
120	select ARCH_WANT_IPC_PARSE_VERSION
121	select BUILDTIME_TABLE_SORT
122	select CLONE_BACKWARDS2
123	select CPU_NO_EFFICIENT_FFS if !HAVE_MARCH_Z9_109_FEATURES
124	select DMA_OPS if PCI
125	select DYNAMIC_FTRACE if FUNCTION_TRACER
126	select GENERIC_ALLOCATOR
127	select GENERIC_CPU_AUTOPROBE
128	select GENERIC_CPU_VULNERABILITIES
129	select GENERIC_ENTRY
130	select GENERIC_FIND_FIRST_BIT
131	select GENERIC_GETTIMEOFDAY
132	select GENERIC_PTDUMP
133	select GENERIC_SMP_IDLE_THREAD
134	select GENERIC_TIME_VSYSCALL
135	select GENERIC_VDSO_TIME_NS
136	select HAVE_ALIGNED_STRUCT_PAGE if SLUB
137	select HAVE_ARCH_AUDITSYSCALL
138	select HAVE_ARCH_JUMP_LABEL
139	select HAVE_ARCH_JUMP_LABEL_RELATIVE
140	select HAVE_ARCH_KASAN
141	select HAVE_ARCH_KASAN_VMALLOC
142	select HAVE_ARCH_KCSAN
143	select HAVE_ARCH_KFENCE
144	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
145	select HAVE_ARCH_SECCOMP_FILTER
146	select HAVE_ARCH_SOFT_DIRTY
147	select HAVE_ARCH_TRACEHOOK
148	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
149	select HAVE_ARCH_VMAP_STACK
150	select HAVE_ASM_MODVERSIONS
151	select HAVE_CMPXCHG_DOUBLE
152	select HAVE_CMPXCHG_LOCAL
153	select HAVE_DEBUG_KMEMLEAK
154	select HAVE_DMA_CONTIGUOUS
155	select HAVE_DYNAMIC_FTRACE
156	select HAVE_DYNAMIC_FTRACE_WITH_ARGS
157	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
158	select HAVE_DYNAMIC_FTRACE_WITH_REGS
159	select HAVE_EBPF_JIT if PACK_STACK && HAVE_MARCH_Z196_FEATURES
160	select HAVE_EFFICIENT_UNALIGNED_ACCESS
161	select HAVE_FAST_GUP
162	select HAVE_FENTRY
163	select HAVE_FTRACE_MCOUNT_RECORD
164	select HAVE_FUNCTION_ARG_ACCESS_API
165	select HAVE_FUNCTION_ERROR_INJECTION
166	select HAVE_FUNCTION_GRAPH_TRACER
167	select HAVE_FUNCTION_TRACER
168	select HAVE_FUTEX_CMPXCHG if FUTEX
169	select HAVE_GCC_PLUGINS
170	select HAVE_GENERIC_VDSO
171	select HAVE_IOREMAP_PROT if PCI
172	select HAVE_KERNEL_BZIP2
173	select HAVE_KERNEL_GZIP
174	select HAVE_KERNEL_LZ4
175	select HAVE_KERNEL_LZMA
176	select HAVE_KERNEL_LZO
177	select HAVE_KERNEL_UNCOMPRESSED
178	select HAVE_KERNEL_XZ
179	select HAVE_KERNEL_ZSTD
180	select HAVE_KPROBES
181	select HAVE_KPROBES_ON_FTRACE
182	select HAVE_KRETPROBES
183	select HAVE_KVM
184	select HAVE_LIVEPATCH
185	select HAVE_MEMBLOCK_PHYS_MAP
186	select HAVE_MOD_ARCH_SPECIFIC
187	select HAVE_NMI
188	select HAVE_NOP_MCOUNT
189	select HAVE_PCI
190	select HAVE_PERF_EVENTS
191	select HAVE_PERF_REGS
192	select HAVE_PERF_USER_STACK_DUMP
193	select HAVE_REGS_AND_STACK_ACCESS_API
194	select HAVE_RELIABLE_STACKTRACE
195	select HAVE_RSEQ
196	select HAVE_SAMPLE_FTRACE_DIRECT
197	select HAVE_SOFTIRQ_ON_OWN_STACK
198	select HAVE_SYSCALL_TRACEPOINTS
199	select HAVE_VIRT_CPU_ACCOUNTING
200	select HAVE_VIRT_CPU_ACCOUNTING_IDLE
201	select IOMMU_HELPER		if PCI
202	select IOMMU_SUPPORT		if PCI
203	select MMU_GATHER_NO_GATHER
204	select MMU_GATHER_RCU_TABLE_FREE
205	select MODULES_USE_ELF_RELA
206	select NEED_DMA_MAP_STATE	if PCI
207	select NEED_SG_DMA_LENGTH	if PCI
208	select OLD_SIGACTION
209	select OLD_SIGSUSPEND3
210	select PCI_DOMAINS		if PCI
211	select PCI_MSI			if PCI
212	select PCI_MSI_ARCH_FALLBACKS	if PCI_MSI
213	select SPARSE_IRQ
214	select SWIOTLB
215	select SYSCTL_EXCEPTION_TRACE
216	select THREAD_INFO_IN_TASK
217	select TRACE_IRQFLAGS_SUPPORT
218	select TTY
219	select VIRT_CPU_ACCOUNTING
220	select ZONE_DMA
221	# Note: keep the above list sorted alphabetically
222
223config SCHED_OMIT_FRAME_POINTER
224	def_bool y
225
226config PGTABLE_LEVELS
227	int
228	default 5
229
230source "kernel/livepatch/Kconfig"
231
232menu "Processor type and features"
233
234config HAVE_MARCH_Z900_FEATURES
235	def_bool n
236
237config HAVE_MARCH_Z990_FEATURES
238	def_bool n
239	select HAVE_MARCH_Z900_FEATURES
240
241config HAVE_MARCH_Z9_109_FEATURES
242	def_bool n
243	select HAVE_MARCH_Z990_FEATURES
244
245config HAVE_MARCH_Z10_FEATURES
246	def_bool n
247	select HAVE_MARCH_Z9_109_FEATURES
248
249config HAVE_MARCH_Z196_FEATURES
250	def_bool n
251	select HAVE_MARCH_Z10_FEATURES
252
253config HAVE_MARCH_ZEC12_FEATURES
254	def_bool n
255	select HAVE_MARCH_Z196_FEATURES
256
257config HAVE_MARCH_Z13_FEATURES
258	def_bool n
259	select HAVE_MARCH_ZEC12_FEATURES
260
261config HAVE_MARCH_Z14_FEATURES
262	def_bool n
263	select HAVE_MARCH_Z13_FEATURES
264
265config HAVE_MARCH_Z15_FEATURES
266	def_bool n
267	select HAVE_MARCH_Z14_FEATURES
268
269choice
270	prompt "Processor type"
271	default MARCH_Z196
272
273config MARCH_Z900
274	bool "IBM zSeries model z800 and z900"
275	select HAVE_MARCH_Z900_FEATURES
276	depends on $(cc-option,-march=z900)
277	help
278	  Select this to enable optimizations for model z800/z900 (2064 and
279	  2066 series). This will enable some optimizations that are not
280	  available on older ESA/390 (31 Bit) only CPUs.
281
282config MARCH_Z990
283	bool "IBM zSeries model z890 and z990"
284	select HAVE_MARCH_Z990_FEATURES
285	depends on $(cc-option,-march=z990)
286	help
287	  Select this to enable optimizations for model z890/z990 (2084 and
288	  2086 series). The kernel will be slightly faster but will not work
289	  on older machines.
290
291config MARCH_Z9_109
292	bool "IBM System z9"
293	select HAVE_MARCH_Z9_109_FEATURES
294	depends on $(cc-option,-march=z9-109)
295	help
296	  Select this to enable optimizations for IBM System z9 (2094 and
297	  2096 series). The kernel will be slightly faster but will not work
298	  on older machines.
299
300config MARCH_Z10
301	bool "IBM System z10"
302	select HAVE_MARCH_Z10_FEATURES
303	depends on $(cc-option,-march=z10)
304	help
305	  Select this to enable optimizations for IBM System z10 (2097 and
306	  2098 series). The kernel will be slightly faster but will not work
307	  on older machines.
308
309config MARCH_Z196
310	bool "IBM zEnterprise 114 and 196"
311	select HAVE_MARCH_Z196_FEATURES
312	depends on $(cc-option,-march=z196)
313	help
314	  Select this to enable optimizations for IBM zEnterprise 114 and 196
315	  (2818 and 2817 series). The kernel will be slightly faster but will
316	  not work on older machines.
317
318config MARCH_ZEC12
319	bool "IBM zBC12 and zEC12"
320	select HAVE_MARCH_ZEC12_FEATURES
321	depends on $(cc-option,-march=zEC12)
322	help
323	  Select this to enable optimizations for IBM zBC12 and zEC12 (2828 and
324	  2827 series). The kernel will be slightly faster but will not work on
325	  older machines.
326
327config MARCH_Z13
328	bool "IBM z13s and z13"
329	select HAVE_MARCH_Z13_FEATURES
330	depends on $(cc-option,-march=z13)
331	help
332	  Select this to enable optimizations for IBM z13s and z13 (2965 and
333	  2964 series). The kernel will be slightly faster but will not work on
334	  older machines.
335
336config MARCH_Z14
337	bool "IBM z14 ZR1 and z14"
338	select HAVE_MARCH_Z14_FEATURES
339	depends on $(cc-option,-march=z14)
340	help
341	  Select this to enable optimizations for IBM z14 ZR1 and z14 (3907
342	  and 3906 series). The kernel will be slightly faster but will not
343	  work on older machines.
344
345config MARCH_Z15
346	bool "IBM z15"
347	select HAVE_MARCH_Z15_FEATURES
348	depends on $(cc-option,-march=z15)
349	help
350	  Select this to enable optimizations for IBM z15 (8562
351	  and 8561 series). The kernel will be slightly faster but will not
352	  work on older machines.
353
354endchoice
355
356config MARCH_Z900_TUNE
357	def_bool TUNE_Z900 || MARCH_Z900 && TUNE_DEFAULT
358
359config MARCH_Z990_TUNE
360	def_bool TUNE_Z990 || MARCH_Z990 && TUNE_DEFAULT
361
362config MARCH_Z9_109_TUNE
363	def_bool TUNE_Z9_109 || MARCH_Z9_109 && TUNE_DEFAULT
364
365config MARCH_Z10_TUNE
366	def_bool TUNE_Z10 || MARCH_Z10 && TUNE_DEFAULT
367
368config MARCH_Z196_TUNE
369	def_bool TUNE_Z196 || MARCH_Z196 && TUNE_DEFAULT
370
371config MARCH_ZEC12_TUNE
372	def_bool TUNE_ZEC12 || MARCH_ZEC12 && TUNE_DEFAULT
373
374config MARCH_Z13_TUNE
375	def_bool TUNE_Z13 || MARCH_Z13 && TUNE_DEFAULT
376
377config MARCH_Z14_TUNE
378	def_bool TUNE_Z14 || MARCH_Z14 && TUNE_DEFAULT
379
380config MARCH_Z15_TUNE
381	def_bool TUNE_Z15 || MARCH_Z15 && TUNE_DEFAULT
382
383choice
384	prompt "Tune code generation"
385	default TUNE_DEFAULT
386	help
387	  Cause the compiler to tune (-mtune) the generated code for a machine.
388	  This will make the code run faster on the selected machine but
389	  somewhat slower on other machines.
390	  This option only changes how the compiler emits instructions, not the
391	  selection of instructions itself, so the resulting kernel will run on
392	  all other machines.
393
394config TUNE_DEFAULT
395	bool "Default"
396	help
397	  Tune the generated code for the target processor for which the kernel
398	  will be compiled.
399
400config TUNE_Z900
401	bool "IBM zSeries model z800 and z900"
402	depends on $(cc-option,-mtune=z900)
403
404config TUNE_Z990
405	bool "IBM zSeries model z890 and z990"
406	depends on $(cc-option,-mtune=z990)
407
408config TUNE_Z9_109
409	bool "IBM System z9"
410	depends on $(cc-option,-mtune=z9-109)
411
412config TUNE_Z10
413	bool "IBM System z10"
414	depends on $(cc-option,-mtune=z10)
415
416config TUNE_Z196
417	bool "IBM zEnterprise 114 and 196"
418	depends on $(cc-option,-mtune=z196)
419
420config TUNE_ZEC12
421	bool "IBM zBC12 and zEC12"
422	depends on $(cc-option,-mtune=zEC12)
423
424config TUNE_Z13
425	bool "IBM z13s and z13"
426	depends on $(cc-option,-mtune=z13)
427
428config TUNE_Z14
429	bool "IBM z14 ZR1 and z14"
430	depends on $(cc-option,-mtune=z14)
431
432config TUNE_Z15
433	bool "IBM z15"
434	depends on $(cc-option,-mtune=z15)
435
436endchoice
437
438config 64BIT
439	def_bool y
440
441config COMMAND_LINE_SIZE
442	int "Maximum size of kernel command line"
443	default 4096
444	range 896 1048576
445	help
446	  This allows you to specify the maximum length of the kernel command
447	  line.
448
449config COMPAT
450	def_bool y
451	prompt "Kernel support for 31 bit emulation"
452	select ARCH_WANT_OLD_COMPAT_IPC
453	select COMPAT_OLD_SIGACTION
454	select HAVE_UID16
455	depends on MULTIUSER
456	depends on !CC_IS_CLANG
457	help
458	  Select this option if you want to enable your system kernel to
459	  handle system-calls from ELF binaries for 31 bit ESA.  This option
460	  (and some other stuff like libraries and such) is needed for
461	  executing 31 bit applications.  It is safe to say "Y".
462
463config SYSVIPC_COMPAT
464	def_bool y if COMPAT && SYSVIPC
465
466config SMP
467	def_bool y
468
469config NR_CPUS
470	int "Maximum number of CPUs (2-512)"
471	range 2 512
472	default "64"
473	help
474	  This allows you to specify the maximum number of CPUs which this
475	  kernel will support. The maximum supported value is 512 and the
476	  minimum value which makes sense is 2.
477
478	  This is purely to save memory - each supported CPU adds
479	  approximately sixteen kilobytes to the kernel image.
480
481config HOTPLUG_CPU
482	def_bool y
483
484config NUMA
485	bool "NUMA support"
486	depends on SCHED_TOPOLOGY
487	default n
488	help
489	  Enable NUMA support
490
491	  This option adds NUMA support to the kernel.
492
493config NODES_SHIFT
494	int
495	depends on NUMA
496	default "1"
497
498config SCHED_SMT
499	def_bool n
500
501config SCHED_MC
502	def_bool n
503
504config SCHED_BOOK
505	def_bool n
506
507config SCHED_DRAWER
508	def_bool n
509
510config SCHED_TOPOLOGY
511	def_bool y
512	prompt "Topology scheduler support"
513	select SCHED_SMT
514	select SCHED_MC
515	select SCHED_BOOK
516	select SCHED_DRAWER
517	help
518	  Topology scheduler support improves the CPU scheduler's decision
519	  making when dealing with machines that have multi-threading,
520	  multiple cores or multiple books.
521
522source "kernel/Kconfig.hz"
523
524config KEXEC
525	def_bool y
526	select KEXEC_CORE
527
528config KEXEC_FILE
529	bool "kexec file based system call"
530	select KEXEC_CORE
531	select BUILD_BIN2C
532	depends on CRYPTO
533	depends on CRYPTO_SHA256
534	depends on CRYPTO_SHA256_S390
535	help
536	  Enable the kexec file based system call. In contrast to the normal
537	  kexec system call this system call takes file descriptors for the
538	  kernel and initramfs as arguments.
539
540config ARCH_HAS_KEXEC_PURGATORY
541	def_bool y
542	depends on KEXEC_FILE
543
544config KEXEC_SIG
545	bool "Verify kernel signature during kexec_file_load() syscall"
546	depends on KEXEC_FILE && MODULE_SIG_FORMAT
547	help
548	  This option makes kernel signature verification mandatory for
549	  the kexec_file_load() syscall.
550
551	  In addition to that option, you need to enable signature
552	  verification for the corresponding kernel image type being
553	  loaded in order for this to work.
554
555config ARCH_RANDOM
556	def_bool y
557	prompt "s390 architectural random number generation API"
558	help
559	  Enable the s390 architectural random number generation API
560	  to provide random data for all consumers within the Linux
561	  kernel.
562
563	  When enabled the arch_random_* functions declared in linux/random.h
564	  are implemented. The implementation is based on the s390 CPACF
565	  instruction subfunction TRNG which provides a real true random
566	  number generator.
567
568	  If unsure, say Y.
569
570config KERNEL_NOBP
571	def_bool n
572	prompt "Enable modified branch prediction for the kernel by default"
573	help
574	  If this option is selected the kernel will switch to a modified
575	  branch prediction mode if the firmware interface is available.
576	  The modified branch prediction mode improves the behaviour in
577	  regard to speculative execution.
578
579	  With the option enabled the kernel parameter "nobp=0" or "nospec"
580	  can be used to run the kernel in the normal branch prediction mode.
581
582	  With the option disabled the modified branch prediction mode is
583	  enabled with the "nobp=1" kernel parameter.
584
585	  If unsure, say N.
586
587config EXPOLINE
588	def_bool n
589	prompt "Avoid speculative indirect branches in the kernel"
590	help
591	  Compile the kernel with the expoline compiler options to guard
592	  against kernel-to-user data leaks by avoiding speculative indirect
593	  branches.
594	  Requires a compiler with -mindirect-branch=thunk support for full
595	  protection. The kernel may run slower.
596
597	  If unsure, say N.
598
599choice
600	prompt "Expoline default"
601	depends on EXPOLINE
602	default EXPOLINE_FULL
603
604config EXPOLINE_OFF
605	bool "spectre_v2=off"
606
607config EXPOLINE_AUTO
608	bool "spectre_v2=auto"
609
610config EXPOLINE_FULL
611	bool "spectre_v2=on"
612
613endchoice
614
615config RELOCATABLE
616	bool "Build a relocatable kernel"
617	select MODULE_REL_CRCS if MODVERSIONS
618	default y
619	help
620	  This builds a kernel image that retains relocation information
621	  so it can be loaded at an arbitrary address.
622	  The kernel is linked as a position-independent executable (PIE)
623	  and contains dynamic relocations which are processed early in the
624	  bootup process.
625	  The relocations make the kernel image about 15% larger (compressed
626	  10%), but are discarded at runtime.
627
628config RANDOMIZE_BASE
629	bool "Randomize the address of the kernel image (KASLR)"
630	depends on RELOCATABLE
631	default y
632	help
633	  In support of Kernel Address Space Layout Randomization (KASLR),
634	  this randomizes the address at which the kernel image is loaded,
635	  as a security feature that deters exploit attempts relying on
636	  knowledge of the location of kernel internals.
637
638endmenu
639
640menu "Memory setup"
641
642config ARCH_SPARSEMEM_ENABLE
643	def_bool y
644	select SPARSEMEM_VMEMMAP_ENABLE
645	select SPARSEMEM_VMEMMAP
646
647config ARCH_SPARSEMEM_DEFAULT
648	def_bool y
649
650config MAX_PHYSMEM_BITS
651	int "Maximum size of supported physical memory in bits (42-53)"
652	range 42 53
653	default "46"
654	help
655	  This option specifies the maximum supported size of physical memory
656	  in bits. Supported is any size between 2^42 (4TB) and 2^53 (8PB).
657	  Increasing the number of bits also increases the kernel image size.
658	  By default 46 bits (64TB) are supported.
659
660config PACK_STACK
661	def_bool y
662	prompt "Pack kernel stack"
663	help
664	  This option enables the compiler option -mkernel-backchain if it
665	  is available. If the option is available the compiler supports
666	  the new stack layout which dramatically reduces the minimum stack
667	  frame size. With an old compiler a non-leaf function needs a
668	  minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
669	  -mkernel-backchain the minimum size drops to 16 byte on 31 bit
670	  and 24 byte on 64 bit.
671
672	  Say Y if you are unsure.
673
674config CHECK_STACK
675	def_bool y
676	depends on !VMAP_STACK
677	prompt "Detect kernel stack overflow"
678	help
679	  This option enables the compiler option -mstack-guard and
680	  -mstack-size if they are available. If the compiler supports them
681	  it will emit additional code to each function prolog to trigger
682	  an illegal operation if the kernel stack is about to overflow.
683
684	  Say N if you are unsure.
685
686config STACK_GUARD
687	int "Size of the guard area (128-1024)"
688	range 128 1024
689	depends on CHECK_STACK
690	default "256"
691	help
692	  This allows you to specify the size of the guard area at the lower
693	  end of the kernel stack. If the kernel stack points into the guard
694	  area on function entry an illegal operation is triggered. The size
695	  needs to be a power of 2. Please keep in mind that the size of an
696	  interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
697	  The minimum size for the stack guard should be 256 for 31 bit and
698	  512 for 64 bit.
699
700endmenu
701
702menu "I/O subsystem"
703
704config QDIO
705	def_tristate y
706	prompt "QDIO support"
707	help
708	  This driver provides the Queued Direct I/O base support for
709	  IBM System z.
710
711	  To compile this driver as a module, choose M here: the
712	  module will be called qdio.
713
714	  If unsure, say Y.
715
716if PCI
717
718config PCI_NR_FUNCTIONS
719	int "Maximum number of PCI functions (1-4096)"
720	range 1 4096
721	default "512"
722	help
723	  This allows you to specify the maximum number of PCI functions which
724	  this kernel will support.
725
726endif # PCI
727
728config HAS_IOMEM
729	def_bool PCI
730
731config CHSC_SCH
732	def_tristate m
733	prompt "Support for CHSC subchannels"
734	help
735	  This driver allows usage of CHSC subchannels. A CHSC subchannel
736	  is usually present on LPAR only.
737	  The driver creates a device /dev/chsc, which may be used to
738	  obtain I/O configuration information about the machine and
739	  to issue asynchronous chsc commands (DANGEROUS).
740	  You will usually only want to use this interface on a special
741	  LPAR designated for system management.
742
743	  To compile this driver as a module, choose M here: the
744	  module will be called chsc_sch.
745
746	  If unsure, say N.
747
748config SCM_BUS
749	def_bool y
750	prompt "SCM bus driver"
751	help
752	  Bus driver for Storage Class Memory.
753
754config EADM_SCH
755	def_tristate m
756	prompt "Support for EADM subchannels"
757	depends on SCM_BUS
758	help
759	  This driver allows usage of EADM subchannels. EADM subchannels act
760	  as a communication vehicle for SCM increments.
761
762	  To compile this driver as a module, choose M here: the
763	  module will be called eadm_sch.
764
765config VFIO_CCW
766	def_tristate n
767	prompt "Support for VFIO-CCW subchannels"
768	depends on S390_CCW_IOMMU && VFIO_MDEV
769	help
770	  This driver allows usage of I/O subchannels via VFIO-CCW.
771
772	  To compile this driver as a module, choose M here: the
773	  module will be called vfio_ccw.
774
775config VFIO_AP
776	def_tristate n
777	prompt "VFIO support for AP devices"
778	depends on S390_AP_IOMMU && VFIO_MDEV && KVM
779	depends on ZCRYPT
780	help
781		This driver grants access to Adjunct Processor (AP) devices
782		via the VFIO mediated device interface.
783
784		To compile this driver as a module, choose M here: the module
785		will be called vfio_ap.
786
787endmenu
788
789menu "Dump support"
790
791config CRASH_DUMP
792	bool "kernel crash dumps"
793	select KEXEC
794	help
795	  Generate crash dump after being started by kexec.
796	  Crash dump kernels are loaded in the main kernel with kexec-tools
797	  into a specially reserved region and then later executed after
798	  a crash by kdump/kexec.
799	  Refer to <file:Documentation/s390/zfcpdump.rst> for more details on this.
800	  This option also enables s390 zfcpdump.
801	  See also <file:Documentation/s390/zfcpdump.rst>
802
803endmenu
804
805config CCW
806	def_bool y
807
808config HAVE_PNETID
809	tristate
810	default (SMC || CCWGROUP)
811
812menu "Virtualization"
813
814config PROTECTED_VIRTUALIZATION_GUEST
815	def_bool n
816	prompt "Protected virtualization guest support"
817	select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
818	help
819	  Select this option, if you want to be able to run this
820	  kernel as a protected virtualization KVM guest.
821	  Protected virtualization capable machines have a mini hypervisor
822	  located at machine level (an ultravisor). With help of the
823	  Ultravisor, KVM will be able to run "protected" VMs, special
824	  VMs whose memory and management data are unavailable to KVM.
825
826config PFAULT
827	def_bool y
828	prompt "Pseudo page fault support"
829	help
830	  Select this option, if you want to use PFAULT pseudo page fault
831	  handling under VM. If running native or in LPAR, this option
832	  has no effect. If your VM does not support PFAULT, PAGEEX
833	  pseudo page fault handling will be used.
834	  Note that VM 4.2 supports PFAULT but has a bug in its
835	  implementation that causes some problems.
836	  Everybody who wants to run Linux under VM != VM4.2 should select
837	  this option.
838
839config CMM
840	def_tristate n
841	prompt "Cooperative memory management"
842	help
843	  Select this option, if you want to enable the kernel interface
844	  to reduce the memory size of the system. This is accomplished
845	  by allocating pages of memory and put them "on hold". This only
846	  makes sense for a system running under VM where the unused pages
847	  will be reused by VM for other guest systems. The interface
848	  allows an external monitor to balance memory of many systems.
849	  Everybody who wants to run Linux under VM should select this
850	  option.
851
852config CMM_IUCV
853	def_bool y
854	prompt "IUCV special message interface to cooperative memory management"
855	depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
856	help
857	  Select this option to enable the special message interface to
858	  the cooperative memory management.
859
860config APPLDATA_BASE
861	def_bool n
862	prompt "Linux - VM Monitor Stream, base infrastructure"
863	depends on PROC_SYSCTL
864	help
865	  This provides a kernel interface for creating and updating z/VM APPLDATA
866	  monitor records. The monitor records are updated at certain time
867	  intervals, once the timer is started.
868	  Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
869	  i.e. enables or disables monitoring on the Linux side.
870	  A custom interval value (in seconds) can be written to
871	  /proc/appldata/interval.
872
873	  Defaults are 60 seconds interval and timer off.
874	  The /proc entries can also be read from, showing the current settings.
875
876config APPLDATA_MEM
877	def_tristate m
878	prompt "Monitor memory management statistics"
879	depends on APPLDATA_BASE && VM_EVENT_COUNTERS
880	help
881	  This provides memory management related data to the Linux - VM Monitor
882	  Stream, like paging/swapping rate, memory utilisation, etc.
883	  Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
884	  APPLDATA monitor record, i.e. enables or disables monitoring this record
885	  on the z/VM side.
886
887	  Default is disabled.
888	  The /proc entry can also be read from, showing the current settings.
889
890	  This can also be compiled as a module, which will be called
891	  appldata_mem.o.
892
893config APPLDATA_OS
894	def_tristate m
895	prompt "Monitor OS statistics"
896	depends on APPLDATA_BASE
897	help
898	  This provides OS related data to the Linux - VM Monitor Stream, like
899	  CPU utilisation, etc.
900	  Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
901	  APPLDATA monitor record, i.e. enables or disables monitoring this record
902	  on the z/VM side.
903
904	  Default is disabled.
905	  This can also be compiled as a module, which will be called
906	  appldata_os.o.
907
908config APPLDATA_NET_SUM
909	def_tristate m
910	prompt "Monitor overall network statistics"
911	depends on APPLDATA_BASE && NET
912	help
913	  This provides network related data to the Linux - VM Monitor Stream,
914	  currently there is only a total sum of network I/O statistics, no
915	  per-interface data.
916	  Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
917	  APPLDATA monitor record, i.e. enables or disables monitoring this record
918	  on the z/VM side.
919
920	  Default is disabled.
921	  This can also be compiled as a module, which will be called
922	  appldata_net_sum.o.
923
924config S390_HYPFS_FS
925	def_bool y
926	prompt "s390 hypervisor file system support"
927	select SYS_HYPERVISOR
928	help
929	  This is a virtual file system intended to provide accounting
930	  information in an s390 hypervisor environment.
931
932source "arch/s390/kvm/Kconfig"
933
934config S390_GUEST
935	def_bool y
936	prompt "s390 support for virtio devices"
937	select TTY
938	select VIRTUALIZATION
939	select VIRTIO
940	help
941	  Enabling this option adds support for virtio based paravirtual device
942	  drivers on s390.
943
944	  Select this option if you want to run the kernel as a guest under
945	  the KVM hypervisor.
946
947endmenu
948
949menu "Selftests"
950
951config S390_UNWIND_SELFTEST
952	def_tristate n
953	depends on KUNIT
954	default KUNIT_ALL_TESTS
955	prompt "Test unwind functions"
956	help
957	  This option enables s390 specific stack unwinder testing kernel
958	  module. This option is not useful for distributions or general
959	  kernels, but only for kernel developers working on architecture code.
960
961	  Say N if you are unsure.
962
963config S390_KPROBES_SANITY_TEST
964	def_tristate n
965	prompt "Enable s390 specific kprobes tests"
966	depends on KPROBES
967	depends on KUNIT
968	help
969	  This option enables an s390 specific kprobes test module. This option
970	  is not useful for distributions or general kernels, but only for kernel
971	  developers working on architecture code.
972
973	  Say N if you are unsure.
974
975endmenu
976