xref: /linux/arch/s390/Kconfig (revision d8310914848223de7ec04d55bd15f013f0dad803)
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_MHP_MEMMAP_ON_MEMORY_ENABLE
117	select ARCH_STACKWALK
118	select ARCH_SUPPORTS_ATOMIC_RMW
119	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
120	select ARCH_SUPPORTS_HUGETLBFS
121	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && CC_IS_CLANG
122	select ARCH_SUPPORTS_NUMA_BALANCING
123	select ARCH_SUPPORTS_PER_VMA_LOCK
124	select ARCH_USE_BUILTIN_BSWAP
125	select ARCH_USE_CMPXCHG_LOCKREF
126	select ARCH_USE_SYM_ANNOTATIONS
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 DCACHE_WORD_ACCESS if !KMSAN
135	select DMA_OPS if PCI
136	select DYNAMIC_FTRACE if FUNCTION_TRACER
137	select FUNCTION_ALIGNMENT_8B if CC_IS_GCC
138	select FUNCTION_ALIGNMENT_16B if !CC_IS_GCC
139	select GENERIC_ALLOCATOR
140	select GENERIC_CPU_AUTOPROBE
141	select GENERIC_CPU_VULNERABILITIES
142	select GENERIC_ENTRY
143	select GENERIC_GETTIMEOFDAY
144	select GENERIC_PTDUMP
145	select GENERIC_SMP_IDLE_THREAD
146	select GENERIC_TIME_VSYSCALL
147	select GENERIC_VDSO_TIME_NS
148	select GENERIC_IOREMAP if PCI
149	select HAVE_ALIGNED_STRUCT_PAGE
150	select HAVE_ARCH_AUDITSYSCALL
151	select HAVE_ARCH_JUMP_LABEL
152	select HAVE_ARCH_JUMP_LABEL_RELATIVE
153	select HAVE_ARCH_KASAN
154	select HAVE_ARCH_KASAN_VMALLOC
155	select HAVE_ARCH_KCSAN
156	select HAVE_ARCH_KFENCE
157	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
158	select HAVE_ARCH_SECCOMP_FILTER
159	select HAVE_ARCH_SOFT_DIRTY
160	select HAVE_ARCH_STACKLEAK
161	select HAVE_ARCH_TRACEHOOK
162	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
163	select HAVE_ARCH_VMAP_STACK
164	select HAVE_ASM_MODVERSIONS
165	select HAVE_CMPXCHG_DOUBLE
166	select HAVE_CMPXCHG_LOCAL
167	select HAVE_DEBUG_KMEMLEAK
168	select HAVE_DMA_CONTIGUOUS
169	select HAVE_DYNAMIC_FTRACE
170	select HAVE_DYNAMIC_FTRACE_WITH_ARGS
171	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
172	select HAVE_DYNAMIC_FTRACE_WITH_REGS
173	select HAVE_EBPF_JIT if HAVE_MARCH_Z196_FEATURES
174	select HAVE_EFFICIENT_UNALIGNED_ACCESS
175	select HAVE_FAST_GUP
176	select HAVE_FENTRY
177	select HAVE_FTRACE_MCOUNT_RECORD
178	select HAVE_FUNCTION_ARG_ACCESS_API
179	select HAVE_FUNCTION_ERROR_INJECTION
180	select HAVE_FUNCTION_GRAPH_RETVAL
181	select HAVE_FUNCTION_GRAPH_TRACER
182	select HAVE_FUNCTION_TRACER
183	select HAVE_GCC_PLUGINS
184	select HAVE_GENERIC_VDSO
185	select HAVE_IOREMAP_PROT if PCI
186	select HAVE_KERNEL_BZIP2
187	select HAVE_KERNEL_GZIP
188	select HAVE_KERNEL_LZ4
189	select HAVE_KERNEL_LZMA
190	select HAVE_KERNEL_LZO
191	select HAVE_KERNEL_UNCOMPRESSED
192	select HAVE_KERNEL_XZ
193	select HAVE_KERNEL_ZSTD
194	select HAVE_KPROBES
195	select HAVE_KPROBES_ON_FTRACE
196	select HAVE_KRETPROBES
197	select HAVE_KVM
198	select HAVE_LIVEPATCH
199	select HAVE_MEMBLOCK_PHYS_MAP
200	select HAVE_MOD_ARCH_SPECIFIC
201	select HAVE_NMI
202	select HAVE_NOP_MCOUNT
203	select HAVE_PCI
204	select HAVE_PERF_EVENTS
205	select HAVE_PERF_REGS
206	select HAVE_PERF_USER_STACK_DUMP
207	select HAVE_REGS_AND_STACK_ACCESS_API
208	select HAVE_RELIABLE_STACKTRACE
209	select HAVE_RETHOOK
210	select HAVE_RSEQ
211	select HAVE_SAMPLE_FTRACE_DIRECT
212	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI
213	select HAVE_SETUP_PER_CPU_AREA
214	select HAVE_SOFTIRQ_ON_OWN_STACK
215	select HAVE_SYSCALL_TRACEPOINTS
216	select HAVE_VIRT_CPU_ACCOUNTING
217	select HAVE_VIRT_CPU_ACCOUNTING_IDLE
218	select IOMMU_HELPER		if PCI
219	select IOMMU_SUPPORT		if PCI
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 USER_STACKTRACE_SUPPORT
239	select VIRT_CPU_ACCOUNTING
240	select ZONE_DMA
241	# Note: keep the above list sorted alphabetically
242
243config SCHED_OMIT_FRAME_POINTER
244	def_bool y
245
246config PGTABLE_LEVELS
247	int
248	default 5
249
250source "kernel/livepatch/Kconfig"
251
252config ARCH_SUPPORTS_KEXEC
253	def_bool y
254
255config ARCH_SUPPORTS_KEXEC_FILE
256	def_bool y
257
258config ARCH_SUPPORTS_KEXEC_SIG
259	def_bool MODULE_SIG_FORMAT
260
261config ARCH_SUPPORTS_KEXEC_PURGATORY
262	def_bool y
263
264config ARCH_SUPPORTS_CRASH_DUMP
265	def_bool y
266	help
267	  Refer to <file:Documentation/arch/s390/zfcpdump.rst> for more details on this.
268	  This option also enables s390 zfcpdump.
269	  See also <file:Documentation/arch/s390/zfcpdump.rst>
270
271menu "Processor type and features"
272
273config HAVE_MARCH_Z10_FEATURES
274	def_bool n
275
276config HAVE_MARCH_Z196_FEATURES
277	def_bool n
278	select HAVE_MARCH_Z10_FEATURES
279
280config HAVE_MARCH_ZEC12_FEATURES
281	def_bool n
282	select HAVE_MARCH_Z196_FEATURES
283
284config HAVE_MARCH_Z13_FEATURES
285	def_bool n
286	select HAVE_MARCH_ZEC12_FEATURES
287
288config HAVE_MARCH_Z14_FEATURES
289	def_bool n
290	select HAVE_MARCH_Z13_FEATURES
291
292config HAVE_MARCH_Z15_FEATURES
293	def_bool n
294	select HAVE_MARCH_Z14_FEATURES
295
296config HAVE_MARCH_Z16_FEATURES
297	def_bool n
298	select HAVE_MARCH_Z15_FEATURES
299
300choice
301	prompt "Processor type"
302	default MARCH_Z196
303
304config MARCH_Z10
305	bool "IBM System z10"
306	select HAVE_MARCH_Z10_FEATURES
307	depends on $(cc-option,-march=z10)
308	help
309	  Select this to enable optimizations for IBM System z10 (2097 and 2098
310	  series). This is the oldest machine generation currently supported.
311
312config MARCH_Z196
313	bool "IBM zEnterprise 114 and 196"
314	select HAVE_MARCH_Z196_FEATURES
315	depends on $(cc-option,-march=z196)
316	help
317	  Select this to enable optimizations for IBM zEnterprise 114 and 196
318	  (2818 and 2817 series). The kernel will be slightly faster but will
319	  not work on older machines.
320
321config MARCH_ZEC12
322	bool "IBM zBC12 and zEC12"
323	select HAVE_MARCH_ZEC12_FEATURES
324	depends on $(cc-option,-march=zEC12)
325	help
326	  Select this to enable optimizations for IBM zBC12 and zEC12 (2828 and
327	  2827 series). The kernel will be slightly faster but will not work on
328	  older machines.
329
330config MARCH_Z13
331	bool "IBM z13s and z13"
332	select HAVE_MARCH_Z13_FEATURES
333	depends on $(cc-option,-march=z13)
334	help
335	  Select this to enable optimizations for IBM z13s and z13 (2965 and
336	  2964 series). The kernel will be slightly faster but will not work on
337	  older machines.
338
339config MARCH_Z14
340	bool "IBM z14 ZR1 and z14"
341	select HAVE_MARCH_Z14_FEATURES
342	depends on $(cc-option,-march=z14)
343	help
344	  Select this to enable optimizations for IBM z14 ZR1 and z14 (3907
345	  and 3906 series). The kernel will be slightly faster but will not
346	  work on older machines.
347
348config MARCH_Z15
349	bool "IBM z15"
350	select HAVE_MARCH_Z15_FEATURES
351	depends on $(cc-option,-march=z15)
352	help
353	  Select this to enable optimizations for IBM z15 (8562
354	  and 8561 series). The kernel will be slightly faster but will not
355	  work on older machines.
356
357config MARCH_Z16
358	bool "IBM z16"
359	select HAVE_MARCH_Z16_FEATURES
360	depends on $(cc-option,-march=z16)
361	help
362	  Select this to enable optimizations for IBM z16 (3931 and
363	  3932 series).
364
365endchoice
366
367config MARCH_Z10_TUNE
368	def_bool TUNE_Z10 || MARCH_Z10 && TUNE_DEFAULT
369
370config MARCH_Z196_TUNE
371	def_bool TUNE_Z196 || MARCH_Z196 && TUNE_DEFAULT
372
373config MARCH_ZEC12_TUNE
374	def_bool TUNE_ZEC12 || MARCH_ZEC12 && TUNE_DEFAULT
375
376config MARCH_Z13_TUNE
377	def_bool TUNE_Z13 || MARCH_Z13 && TUNE_DEFAULT
378
379config MARCH_Z14_TUNE
380	def_bool TUNE_Z14 || MARCH_Z14 && TUNE_DEFAULT
381
382config MARCH_Z15_TUNE
383	def_bool TUNE_Z15 || MARCH_Z15 && TUNE_DEFAULT
384
385config MARCH_Z16_TUNE
386	def_bool TUNE_Z16 || MARCH_Z16 && TUNE_DEFAULT
387
388choice
389	prompt "Tune code generation"
390	default TUNE_DEFAULT
391	help
392	  Cause the compiler to tune (-mtune) the generated code for a machine.
393	  This will make the code run faster on the selected machine but
394	  somewhat slower on other machines.
395	  This option only changes how the compiler emits instructions, not the
396	  selection of instructions itself, so the resulting kernel will run on
397	  all other machines.
398
399config TUNE_DEFAULT
400	bool "Default"
401	help
402	  Tune the generated code for the target processor for which the kernel
403	  will be compiled.
404
405config TUNE_Z10
406	bool "IBM System z10"
407
408config TUNE_Z196
409	bool "IBM zEnterprise 114 and 196"
410	depends on $(cc-option,-mtune=z196)
411
412config TUNE_ZEC12
413	bool "IBM zBC12 and zEC12"
414	depends on $(cc-option,-mtune=zEC12)
415
416config TUNE_Z13
417	bool "IBM z13s and z13"
418	depends on $(cc-option,-mtune=z13)
419
420config TUNE_Z14
421	bool "IBM z14 ZR1 and z14"
422	depends on $(cc-option,-mtune=z14)
423
424config TUNE_Z15
425	bool "IBM z15"
426	depends on $(cc-option,-mtune=z15)
427
428config TUNE_Z16
429	bool "IBM z16"
430	depends on $(cc-option,-mtune=z16)
431
432endchoice
433
434config 64BIT
435	def_bool y
436
437config COMMAND_LINE_SIZE
438	int "Maximum size of kernel command line"
439	default 4096
440	range 896 1048576
441	help
442	  This allows you to specify the maximum length of the kernel command
443	  line.
444
445config COMPAT
446	def_bool n
447	prompt "Kernel support for 31 bit emulation"
448	select ARCH_WANT_OLD_COMPAT_IPC
449	select COMPAT_OLD_SIGACTION
450	select HAVE_UID16
451	depends on MULTIUSER
452	depends on !CC_IS_CLANG
453	help
454	  Select this option if you want to enable your system kernel to
455	  handle system-calls from ELF binaries for 31 bit ESA.  This option
456	  (and some other stuff like libraries and such) is needed for
457	  executing 31 bit applications.
458
459	  If unsure say N.
460
461config SMP
462	def_bool y
463
464config NR_CPUS
465	int "Maximum number of CPUs (2-512)"
466	range 2 512
467	default "64"
468	help
469	  This allows you to specify the maximum number of CPUs which this
470	  kernel will support. The maximum supported value is 512 and the
471	  minimum value which makes sense is 2.
472
473	  This is purely to save memory - each supported CPU adds
474	  approximately sixteen kilobytes to the kernel image.
475
476config HOTPLUG_CPU
477	def_bool y
478
479config NUMA
480	bool "NUMA support"
481	depends on SCHED_TOPOLOGY
482	default n
483	help
484	  Enable NUMA support
485
486	  This option adds NUMA support to the kernel.
487
488config NODES_SHIFT
489	int
490	depends on NUMA
491	default "1"
492
493config SCHED_SMT
494	def_bool n
495
496config SCHED_MC
497	def_bool n
498
499config SCHED_TOPOLOGY
500	def_bool y
501	prompt "Topology scheduler support"
502	select SCHED_SMT
503	select SCHED_MC
504	help
505	  Topology scheduler support improves the CPU scheduler's decision
506	  making when dealing with machines that have multi-threading,
507	  multiple cores or multiple books.
508
509source "kernel/Kconfig.hz"
510
511config CERT_STORE
512	bool "Get user certificates via DIAG320"
513	depends on KEYS
514	select CRYPTO_LIB_SHA256
515	help
516	  Enable this option if you want to access user-provided secure boot
517	  certificates via DIAG 0x320.
518
519	  These certificates will be made available via the keyring named
520	  'cert_store'.
521
522config KERNEL_NOBP
523	def_bool n
524	prompt "Enable modified branch prediction for the kernel by default"
525	help
526	  If this option is selected the kernel will switch to a modified
527	  branch prediction mode if the firmware interface is available.
528	  The modified branch prediction mode improves the behaviour in
529	  regard to speculative execution.
530
531	  With the option enabled the kernel parameter "nobp=0" or "nospec"
532	  can be used to run the kernel in the normal branch prediction mode.
533
534	  With the option disabled the modified branch prediction mode is
535	  enabled with the "nobp=1" kernel parameter.
536
537	  If unsure, say N.
538
539config EXPOLINE
540	def_bool n
541	depends on $(cc-option,-mindirect-branch=thunk)
542	prompt "Avoid speculative indirect branches in the kernel"
543	help
544	  Compile the kernel with the expoline compiler options to guard
545	  against kernel-to-user data leaks by avoiding speculative indirect
546	  branches.
547	  Requires a compiler with -mindirect-branch=thunk support for full
548	  protection. The kernel may run slower.
549
550	  If unsure, say N.
551
552config EXPOLINE_EXTERN
553	def_bool n
554	depends on EXPOLINE
555	depends on CC_IS_GCC && GCC_VERSION >= 110200
556	depends on $(success,$(srctree)/arch/s390/tools/gcc-thunk-extern.sh $(CC))
557	prompt "Generate expolines as extern functions."
558	help
559	  This option is required for some tooling like kpatch. The kernel is
560	  compiled with -mindirect-branch=thunk-extern and requires a newer
561	  compiler.
562
563	  If unsure, say N.
564
565choice
566	prompt "Expoline default"
567	depends on EXPOLINE
568	default EXPOLINE_FULL
569
570config EXPOLINE_OFF
571	bool "spectre_v2=off"
572
573config EXPOLINE_AUTO
574	bool "spectre_v2=auto"
575
576config EXPOLINE_FULL
577	bool "spectre_v2=on"
578
579endchoice
580
581config RELOCATABLE
582	def_bool y
583	help
584	  This builds a kernel image that retains relocation information
585	  so it can be loaded at an arbitrary address.
586	  The kernel is linked as a position-independent executable (PIE)
587	  and contains dynamic relocations which are processed early in the
588	  bootup process.
589	  The relocations make the kernel image about 15% larger (compressed
590	  10%), but are discarded at runtime.
591	  Note: this option exists only for documentation purposes, please do
592	  not remove it.
593
594config RANDOMIZE_BASE
595	bool "Randomize the address of the kernel image (KASLR)"
596	default y
597	help
598	  In support of Kernel Address Space Layout Randomization (KASLR),
599	  this randomizes the address at which the kernel image is loaded,
600	  as a security feature that deters exploit attempts relying on
601	  knowledge of the location of kernel internals.
602
603endmenu
604
605menu "Memory setup"
606
607config ARCH_SPARSEMEM_ENABLE
608	def_bool y
609	select SPARSEMEM_VMEMMAP_ENABLE
610	select SPARSEMEM_VMEMMAP
611
612config ARCH_SPARSEMEM_DEFAULT
613	def_bool y
614
615config MAX_PHYSMEM_BITS
616	int "Maximum size of supported physical memory in bits (42-53)"
617	range 42 53
618	default "46"
619	help
620	  This option specifies the maximum supported size of physical memory
621	  in bits. Supported is any size between 2^42 (4TB) and 2^53 (8PB).
622	  Increasing the number of bits also increases the kernel image size.
623	  By default 46 bits (64TB) are supported.
624
625config CHECK_STACK
626	def_bool y
627	depends on !VMAP_STACK
628	prompt "Detect kernel stack overflow"
629	help
630	  This option enables the compiler option -mstack-guard and
631	  -mstack-size if they are available. If the compiler supports them
632	  it will emit additional code to each function prolog to trigger
633	  an illegal operation if the kernel stack is about to overflow.
634
635	  Say N if you are unsure.
636
637config STACK_GUARD
638	int "Size of the guard area (128-1024)"
639	range 128 1024
640	depends on CHECK_STACK
641	default "256"
642	help
643	  This allows you to specify the size of the guard area at the lower
644	  end of the kernel stack. If the kernel stack points into the guard
645	  area on function entry an illegal operation is triggered. The size
646	  needs to be a power of 2. Please keep in mind that the size of an
647	  interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
648	  The minimum size for the stack guard should be 256 for 31 bit and
649	  512 for 64 bit.
650
651endmenu
652
653menu "I/O subsystem"
654
655config QDIO
656	def_tristate y
657	prompt "QDIO support"
658	help
659	  This driver provides the Queued Direct I/O base support for
660	  IBM System z.
661
662	  To compile this driver as a module, choose M here: the
663	  module will be called qdio.
664
665	  If unsure, say Y.
666
667if PCI
668
669config PCI_NR_FUNCTIONS
670	int "Maximum number of PCI functions (1-4096)"
671	range 1 4096
672	default "512"
673	help
674	  This allows you to specify the maximum number of PCI functions which
675	  this kernel will support.
676
677endif # PCI
678
679config HAS_IOMEM
680	def_bool PCI
681
682config CHSC_SCH
683	def_tristate m
684	prompt "Support for CHSC subchannels"
685	help
686	  This driver allows usage of CHSC subchannels. A CHSC subchannel
687	  is usually present on LPAR only.
688	  The driver creates a device /dev/chsc, which may be used to
689	  obtain I/O configuration information about the machine and
690	  to issue asynchronous chsc commands (DANGEROUS).
691	  You will usually only want to use this interface on a special
692	  LPAR designated for system management.
693
694	  To compile this driver as a module, choose M here: the
695	  module will be called chsc_sch.
696
697	  If unsure, say N.
698
699config SCM_BUS
700	def_bool y
701	prompt "SCM bus driver"
702	help
703	  Bus driver for Storage Class Memory.
704
705config EADM_SCH
706	def_tristate m
707	prompt "Support for EADM subchannels"
708	depends on SCM_BUS
709	help
710	  This driver allows usage of EADM subchannels. EADM subchannels act
711	  as a communication vehicle for SCM increments.
712
713	  To compile this driver as a module, choose M here: the
714	  module will be called eadm_sch.
715
716config VFIO_CCW
717	def_tristate n
718	prompt "Support for VFIO-CCW subchannels"
719	depends on VFIO
720	select VFIO_MDEV
721	help
722	  This driver allows usage of I/O subchannels via VFIO-CCW.
723
724	  To compile this driver as a module, choose M here: the
725	  module will be called vfio_ccw.
726
727config VFIO_AP
728	def_tristate n
729	prompt "VFIO support for AP devices"
730	depends on KVM
731	depends on VFIO
732	depends on ZCRYPT
733	select VFIO_MDEV
734	help
735	  This driver grants access to Adjunct Processor (AP) devices
736	  via the VFIO mediated device interface.
737
738	  To compile this driver as a module, choose M here: the module
739	  will be called vfio_ap.
740
741endmenu
742
743config CCW
744	def_bool y
745
746config HAVE_PNETID
747	tristate
748	default (SMC || CCWGROUP)
749
750menu "Virtualization"
751
752config PROTECTED_VIRTUALIZATION_GUEST
753	def_bool n
754	prompt "Protected virtualization guest support"
755	help
756	  Select this option, if you want to be able to run this
757	  kernel as a protected virtualization KVM guest.
758	  Protected virtualization capable machines have a mini hypervisor
759	  located at machine level (an ultravisor). With help of the
760	  Ultravisor, KVM will be able to run "protected" VMs, special
761	  VMs whose memory and management data are unavailable to KVM.
762
763config PFAULT
764	def_bool y
765	prompt "Pseudo page fault support"
766	help
767	  Select this option, if you want to use PFAULT pseudo page fault
768	  handling under VM. If running native or in LPAR, this option
769	  has no effect. If your VM does not support PFAULT, PAGEEX
770	  pseudo page fault handling will be used.
771	  Note that VM 4.2 supports PFAULT but has a bug in its
772	  implementation that causes some problems.
773	  Everybody who wants to run Linux under VM != VM4.2 should select
774	  this option.
775
776config CMM
777	def_tristate n
778	prompt "Cooperative memory management"
779	help
780	  Select this option, if you want to enable the kernel interface
781	  to reduce the memory size of the system. This is accomplished
782	  by allocating pages of memory and put them "on hold". This only
783	  makes sense for a system running under VM where the unused pages
784	  will be reused by VM for other guest systems. The interface
785	  allows an external monitor to balance memory of many systems.
786	  Everybody who wants to run Linux under VM should select this
787	  option.
788
789config CMM_IUCV
790	def_bool y
791	prompt "IUCV special message interface to cooperative memory management"
792	depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
793	help
794	  Select this option to enable the special message interface to
795	  the cooperative memory management.
796
797config APPLDATA_BASE
798	def_bool n
799	prompt "Linux - VM Monitor Stream, base infrastructure"
800	depends on PROC_SYSCTL
801	help
802	  This provides a kernel interface for creating and updating z/VM APPLDATA
803	  monitor records. The monitor records are updated at certain time
804	  intervals, once the timer is started.
805	  Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
806	  i.e. enables or disables monitoring on the Linux side.
807	  A custom interval value (in seconds) can be written to
808	  /proc/appldata/interval.
809
810	  Defaults are 60 seconds interval and timer off.
811	  The /proc entries can also be read from, showing the current settings.
812
813config APPLDATA_MEM
814	def_tristate m
815	prompt "Monitor memory management statistics"
816	depends on APPLDATA_BASE && VM_EVENT_COUNTERS
817	help
818	  This provides memory management related data to the Linux - VM Monitor
819	  Stream, like paging/swapping rate, memory utilisation, etc.
820	  Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
821	  APPLDATA monitor record, i.e. enables or disables monitoring this record
822	  on the z/VM side.
823
824	  Default is disabled.
825	  The /proc entry can also be read from, showing the current settings.
826
827	  This can also be compiled as a module, which will be called
828	  appldata_mem.o.
829
830config APPLDATA_OS
831	def_tristate m
832	prompt "Monitor OS statistics"
833	depends on APPLDATA_BASE
834	help
835	  This provides OS related data to the Linux - VM Monitor Stream, like
836	  CPU utilisation, etc.
837	  Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
838	  APPLDATA monitor record, i.e. enables or disables monitoring this record
839	  on the z/VM side.
840
841	  Default is disabled.
842	  This can also be compiled as a module, which will be called
843	  appldata_os.o.
844
845config APPLDATA_NET_SUM
846	def_tristate m
847	prompt "Monitor overall network statistics"
848	depends on APPLDATA_BASE && NET
849	help
850	  This provides network related data to the Linux - VM Monitor Stream,
851	  currently there is only a total sum of network I/O statistics, no
852	  per-interface data.
853	  Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
854	  APPLDATA monitor record, i.e. enables or disables monitoring this record
855	  on the z/VM side.
856
857	  Default is disabled.
858	  This can also be compiled as a module, which will be called
859	  appldata_net_sum.o.
860
861config S390_HYPFS
862	def_bool y
863	prompt "s390 hypervisor information"
864	help
865	  This provides several binary files at (debugfs)/s390_hypfs/ to
866	  provide accounting information in an s390 hypervisor environment.
867
868config S390_HYPFS_FS
869	def_bool n
870	prompt "s390 hypervisor file system support"
871	select SYS_HYPERVISOR
872	depends on S390_HYPFS
873	help
874	  This is a virtual file system intended to provide accounting
875	  information in an s390 hypervisor environment. This file system
876	  is deprecated and should not be used.
877
878	  Say N if you are unsure.
879
880source "arch/s390/kvm/Kconfig"
881
882config S390_GUEST
883	def_bool y
884	prompt "s390 support for virtio devices"
885	select TTY
886	select VIRTUALIZATION
887	select VIRTIO
888	help
889	  Enabling this option adds support for virtio based paravirtual device
890	  drivers on s390.
891
892	  Select this option if you want to run the kernel as a guest under
893	  the KVM hypervisor.
894
895endmenu
896
897config S390_MODULES_SANITY_TEST_HELPERS
898	def_bool n
899
900menu "Selftests"
901
902config S390_UNWIND_SELFTEST
903	def_tristate n
904	depends on KUNIT
905	default KUNIT_ALL_TESTS
906	prompt "Test unwind functions"
907	help
908	  This option enables s390 specific stack unwinder testing kernel
909	  module. This option is not useful for distributions or general
910	  kernels, but only for kernel developers working on architecture code.
911
912	  Say N if you are unsure.
913
914config S390_KPROBES_SANITY_TEST
915	def_tristate n
916	prompt "Enable s390 specific kprobes tests"
917	depends on KPROBES
918	depends on KUNIT
919	help
920	  This option enables an s390 specific kprobes test module. This option
921	  is not useful for distributions or general kernels, but only for kernel
922	  developers working on architecture code.
923
924	  Say N if you are unsure.
925
926config S390_MODULES_SANITY_TEST
927	def_tristate n
928	depends on KUNIT
929	default KUNIT_ALL_TESTS
930	prompt "Enable s390 specific modules tests"
931	select S390_MODULES_SANITY_TEST_HELPERS
932	help
933	  This option enables an s390 specific modules test. This option is
934	  not useful for distributions or general kernels, but only for
935	  kernel developers working on architecture code.
936
937	  Say N if you are unsure.
938endmenu
939