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b2441318 1# SPDX-License-Identifier: GPL-2.0
1da177e4 2config MMU
61d48c2c 3 def_bool y
1da177e4 4
66701b14 5config ZONE_DMA
69dbb2f7 6 def_bool y
66701b14 7
2fd92273
HC
8config CPU_BIG_ENDIAN
9 def_bool y
10
2b105ff9 11config LOCKDEP_SUPPORT
61d48c2c 12 def_bool y
2b105ff9 13
5bdc9b44 14config STACKTRACE_SUPPORT
61d48c2c 15 def_bool y
5bdc9b44 16
1da177e4
LT
17config RWSEM_GENERIC_SPINLOCK
18 bool
19
20config RWSEM_XCHGADD_ALGORITHM
61d48c2c 21 def_bool y
1da177e4 22
f0d1b0b3 23config ARCH_HAS_ILOG2_U32
6f9a3c33 24 def_bool n
f0d1b0b3
DH
25
26config ARCH_HAS_ILOG2_U64
6f9a3c33 27 def_bool n
f0d1b0b3 28
7e33db4e 29config GENERIC_HWEIGHT
61d48c2c 30 def_bool y
7e33db4e 31
c0007f1a 32config GENERIC_BUG
6f9a3c33 33 def_bool y if BUG
c0007f1a 34
52499f40
HC
35config GENERIC_BUG_RELATIVE_POINTERS
36 def_bool y
37
b6b40c53 38config GENERIC_LOCKBREAK
6f9a3c33 39 def_bool y if SMP && PREEMPT
b6b40c53 40
402b0862 41config PGSTE
6f9a3c33 42 def_bool y if KVM
402b0862 43
6a11f75b
AM
44config ARCH_SUPPORTS_DEBUG_PAGEALLOC
45 def_bool y
46
843c48fd
JG
47config AUDIT_ARCH
48 def_bool y
49
ce816fa8 50config NO_IOPORT_MAP
c8717a3d
JG
51 def_bool y
52
53config PCI_QUIRKS
54 def_bool n
55
2a0a5b22 56config ARCH_SUPPORTS_UPROBES
5a79859a 57 def_bool y
2a0a5b22 58
5e785963
VG
59config KASAN_SHADOW_OFFSET
60 hex
61 depends on KASAN
5dff0381 62 default 0x18000000000000 if KASAN_S390_4_LEVEL_PAGING
5e785963
VG
63 default 0x30000000000
64
347a8dc3 65config S390
61d48c2c 66 def_bool y
23fefe11 67 select ARCH_BINFMT_ELF_STATE
21266be9 68 select ARCH_HAS_DEVMEM_IS_ALLOWED
2b68f6ca 69 select ARCH_HAS_ELF_RANDOMIZE
79962038 70 select ARCH_HAS_FORTIFY_SOURCE
957e3fac 71 select ARCH_HAS_GCOV_PROFILE_ALL
e1073d1e 72 select ARCH_HAS_GIGANTIC_PAGE if (MEMORY_ISOLATION && COMPACTION) || CMA
907fa061 73 select ARCH_HAS_KCOV
3010a5ea 74 select ARCH_HAS_PTE_SPECIAL
d2852a22 75 select ARCH_HAS_SET_MEMORY
47523c98 76 select ARCH_HAS_SG_CHAIN
ad21fc4f
LA
77 select ARCH_HAS_STRICT_KERNEL_RWX
78 select ARCH_HAS_STRICT_MODULE_RWX
c42d8c7d 79 select ARCH_HAS_UBSAN_SANITIZE_ALL
0e0d04a8 80 select ARCH_HAVE_NMI_SAFE_CMPXCHG
6beb0009
TG
81 select ARCH_INLINE_READ_LOCK
82 select ARCH_INLINE_READ_LOCK_BH
83 select ARCH_INLINE_READ_LOCK_IRQ
84 select ARCH_INLINE_READ_LOCK_IRQSAVE
0e0d04a8 85 select ARCH_INLINE_READ_TRYLOCK
6beb0009
TG
86 select ARCH_INLINE_READ_UNLOCK
87 select ARCH_INLINE_READ_UNLOCK_BH
88 select ARCH_INLINE_READ_UNLOCK_IRQ
89 select ARCH_INLINE_READ_UNLOCK_IRQRESTORE
0e0d04a8
HC
90 select ARCH_INLINE_SPIN_LOCK
91 select ARCH_INLINE_SPIN_LOCK_BH
92 select ARCH_INLINE_SPIN_LOCK_IRQ
93 select ARCH_INLINE_SPIN_LOCK_IRQSAVE
94 select ARCH_INLINE_SPIN_TRYLOCK
95 select ARCH_INLINE_SPIN_TRYLOCK_BH
96 select ARCH_INLINE_SPIN_UNLOCK
97 select ARCH_INLINE_SPIN_UNLOCK_BH
98 select ARCH_INLINE_SPIN_UNLOCK_IRQ
99 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE
6beb0009
TG
100 select ARCH_INLINE_WRITE_LOCK
101 select ARCH_INLINE_WRITE_LOCK_BH
102 select ARCH_INLINE_WRITE_LOCK_IRQ
103 select ARCH_INLINE_WRITE_LOCK_IRQSAVE
0e0d04a8 104 select ARCH_INLINE_WRITE_TRYLOCK
6beb0009
TG
105 select ARCH_INLINE_WRITE_UNLOCK
106 select ARCH_INLINE_WRITE_UNLOCK_BH
107 select ARCH_INLINE_WRITE_UNLOCK_IRQ
108 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
0e0d04a8 109 select ARCH_SAVE_PAGE_KEYS if HIBERNATION
36e7fdaa 110 select ARCH_SUPPORTS_ATOMIC_RMW
a763bc8b 111 select ARCH_SUPPORTS_NUMA_BALANCING
295d8fa9 112 select ARCH_USE_BUILTIN_BSWAP
efc1d23b 113 select ARCH_USE_CMPXCHG_LOCKREF
3f6813b9 114 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
c1d7e01d 115 select ARCH_WANT_IPC_PARSE_VERSION
0e0d04a8
HC
116 select BUILDTIME_EXTABLE_SORT
117 select CLONE_BACKWARDS2
5d6a0163 118 select DYNAMIC_FTRACE if FUNCTION_TRACER
0e0d04a8 119 select GENERIC_CLOCKEVENTS
8f00b3e2 120 select GENERIC_CPU_AUTOPROBE
0e0d04a8 121 select GENERIC_CPU_DEVICES if !SMP
d424986f 122 select GENERIC_CPU_VULNERABILITIES
746479cd 123 select GENERIC_FIND_FIRST_BIT
e80e7813 124 select GENERIC_SMP_IDLE_THREAD
79c74ecb 125 select GENERIC_TIME_VSYSCALL
0e0d04a8 126 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
7a017721 127 select HAVE_ARCH_AUDITSYSCALL
5a79859a 128 select HAVE_ARCH_JUMP_LABEL
13ddb52c 129 select HAVE_ARCH_JUMP_LABEL_RELATIVE
42db5ed8 130 select HAVE_ARCH_KASAN
fff7fb0b 131 select CPU_NO_EFFICIENT_FFS if !HAVE_MARCH_Z9_109_FEATURES
c63cb468 132 select HAVE_ARCH_SECCOMP_FILTER
5614dd92 133 select HAVE_ARCH_SOFT_DIRTY
0e0d04a8 134 select HAVE_ARCH_TRACEHOOK
5a79859a 135 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
ce3dc447 136 select HAVE_ARCH_VMAP_STACK
6077776b 137 select HAVE_EBPF_JIT if PACK_STACK && HAVE_MARCH_Z196_FEATURES
0e0d04a8
HC
138 select HAVE_CMPXCHG_DOUBLE
139 select HAVE_CMPXCHG_LOCAL
f50c0e63 140 select HAVE_COPY_THREAD_TLS
0e0d04a8 141 select HAVE_DEBUG_KMEMLEAK
e1231b0e 142 select HAVE_DMA_CONTIGUOUS
002e6745 143 select DMA_DIRECT_OPS
5a79859a
HC
144 select HAVE_DYNAMIC_FTRACE
145 select HAVE_DYNAMIC_FTRACE_WITH_REGS
9078a549 146 select HAVE_EFFICIENT_UNALIGNED_ACCESS
d983c89c 147 select HAVE_FENTRY
0e0d04a8 148 select HAVE_FTRACE_MCOUNT_RECORD
5a79859a
HC
149 select HAVE_FUNCTION_GRAPH_TRACER
150 select HAVE_FUNCTION_TRACER
03b8c7b6 151 select HAVE_FUTEX_CMPXCHG if FUTEX
bc00b3ec 152 select HAVE_GCC_PLUGINS
0e0d04a8
HC
153 select HAVE_KERNEL_BZIP2
154 select HAVE_KERNEL_GZIP
8e2872ce 155 select HAVE_KERNEL_LZ4
0e0d04a8
HC
156 select HAVE_KERNEL_LZMA
157 select HAVE_KERNEL_LZO
89b5202e 158 select HAVE_KERNEL_UNCOMPRESSED
0e0d04a8
HC
159 select HAVE_KERNEL_XZ
160 select HAVE_KPROBES
161 select HAVE_KRETPROBES
5a79859a 162 select HAVE_KVM
21042d43 163 select HAVE_LIVEPATCH
c33eff60
HC
164 select HAVE_PERF_REGS
165 select HAVE_PERF_USER_STACK_DUMP
0e0d04a8 166 select HAVE_MEMBLOCK_NODE_MAP
50be6345 167 select HAVE_MEMBLOCK_PHYS_MAP
786d35d4 168 select HAVE_MOD_ARCH_SPECIFIC
d983c89c 169 select HAVE_NOP_MCOUNT
0e0d04a8
HC
170 select HAVE_OPROFILE
171 select HAVE_PERF_EVENTS
172 select HAVE_REGS_AND_STACK_ACCESS_API
9d6d99e3 173 select HAVE_RSEQ
0e0d04a8 174 select HAVE_SYSCALL_TRACEPOINTS
0e0d04a8 175 select HAVE_VIRT_CPU_ACCOUNTING
786d35d4 176 select MODULES_USE_ELF_RELA
7eddd99c 177 select OLD_SIGACTION
93bead43 178 select OLD_SIGSUSPEND3
bb98f396 179 select SPARSE_IRQ
0e0d04a8 180 select SYSCTL_EXCEPTION_TRACE
d5c352cd 181 select THREAD_INFO_IN_TASK
0563416b 182 select TTY
0e0d04a8 183 select VIRT_CPU_ACCOUNTING
40565b5a 184 select ARCH_HAS_SCALED_CPUTIME
93bead43 185 select VIRT_TO_BUS
42a0bb3f 186 select HAVE_NMI
3a368f74 187
1da177e4 188
fca3e357 189config SCHED_OMIT_FRAME_POINTER
6f9a3c33 190 def_bool y
fca3e357 191
c81956c9
KS
192config PGTABLE_LEVELS
193 int
1aea9b3f 194 default 5
c81956c9 195
21042d43
JS
196source "kernel/livepatch/Kconfig"
197
843c48fd
JG
198menu "Processor type and features"
199
200config HAVE_MARCH_Z900_FEATURES
201 def_bool n
202
203config HAVE_MARCH_Z990_FEATURES
204 def_bool n
205 select HAVE_MARCH_Z900_FEATURES
206
207config HAVE_MARCH_Z9_109_FEATURES
208 def_bool n
209 select HAVE_MARCH_Z990_FEATURES
210
211config HAVE_MARCH_Z10_FEATURES
212 def_bool n
213 select HAVE_MARCH_Z9_109_FEATURES
214
215config HAVE_MARCH_Z196_FEATURES
216 def_bool n
217 select HAVE_MARCH_Z10_FEATURES
218
991c1505
HC
219config HAVE_MARCH_ZEC12_FEATURES
220 def_bool n
221 select HAVE_MARCH_Z196_FEATURES
222
f8b2dcbd
MS
223config HAVE_MARCH_Z13_FEATURES
224 def_bool n
225 select HAVE_MARCH_ZEC12_FEATURES
226
6997c323
MS
227config HAVE_MARCH_Z14_FEATURES
228 def_bool n
229 select HAVE_MARCH_Z13_FEATURES
230
843c48fd
JG
231choice
232 prompt "Processor type"
7072276e 233 default MARCH_Z196
1da177e4 234
843c48fd
JG
235config MARCH_Z900
236 bool "IBM zSeries model z800 and z900"
5a79859a 237 select HAVE_MARCH_Z900_FEATURES
843c48fd
JG
238 help
239 Select this to enable optimizations for model z800/z900 (2064 and
240 2066 series). This will enable some optimizations that are not
241 available on older ESA/390 (31 Bit) only CPUs.
242
243config MARCH_Z990
244 bool "IBM zSeries model z890 and z990"
5a79859a 245 select HAVE_MARCH_Z990_FEATURES
843c48fd
JG
246 help
247 Select this to enable optimizations for model z890/z990 (2084 and
248 2086 series). The kernel will be slightly faster but will not work
249 on older machines.
250
251config MARCH_Z9_109
252 bool "IBM System z9"
5a79859a 253 select HAVE_MARCH_Z9_109_FEATURES
843c48fd
JG
254 help
255 Select this to enable optimizations for IBM System z9 (2094 and
256 2096 series). The kernel will be slightly faster but will not work
257 on older machines.
258
259config MARCH_Z10
260 bool "IBM System z10"
5a79859a 261 select HAVE_MARCH_Z10_FEATURES
843c48fd
JG
262 help
263 Select this to enable optimizations for IBM System z10 (2097 and
264 2098 series). The kernel will be slightly faster but will not work
265 on older machines.
266
267config MARCH_Z196
268 bool "IBM zEnterprise 114 and 196"
5a79859a 269 select HAVE_MARCH_Z196_FEATURES
843c48fd
JG
270 help
271 Select this to enable optimizations for IBM zEnterprise 114 and 196
272 (2818 and 2817 series). The kernel will be slightly faster but will
273 not work on older machines.
1da177e4 274
991c1505 275config MARCH_ZEC12
59471227 276 bool "IBM zBC12 and zEC12"
5a79859a 277 select HAVE_MARCH_ZEC12_FEATURES
991c1505 278 help
59471227
HC
279 Select this to enable optimizations for IBM zBC12 and zEC12 (2828 and
280 2827 series). The kernel will be slightly faster but will not work on
281 older machines.
991c1505 282
f8b2dcbd 283config MARCH_Z13
bb3aa614 284 bool "IBM z13s and z13"
5a79859a 285 select HAVE_MARCH_Z13_FEATURES
f8b2dcbd 286 help
bb3aa614
HC
287 Select this to enable optimizations for IBM z13s and z13 (2965 and
288 2964 series). The kernel will be slightly faster but will not work on
289 older machines.
f8b2dcbd 290
6997c323 291config MARCH_Z14
451239eb 292 bool "IBM z14 ZR1 and z14"
6997c323
MS
293 select HAVE_MARCH_Z14_FEATURES
294 help
451239eb
HC
295 Select this to enable optimizations for IBM z14 ZR1 and z14 (3907
296 and 3906 series). The kernel will be slightly faster but will not
297 work on older machines.
6997c323 298
843c48fd 299endchoice
1da177e4 300
1db9e051
HC
301config MARCH_Z900_TUNE
302 def_bool TUNE_Z900 || MARCH_Z900 && TUNE_DEFAULT
303
304config MARCH_Z990_TUNE
305 def_bool TUNE_Z990 || MARCH_Z990 && TUNE_DEFAULT
306
307config MARCH_Z9_109_TUNE
308 def_bool TUNE_Z9_109 || MARCH_Z9_109 && TUNE_DEFAULT
309
310config MARCH_Z10_TUNE
311 def_bool TUNE_Z10 || MARCH_Z10 && TUNE_DEFAULT
312
313config MARCH_Z196_TUNE
314 def_bool TUNE_Z196 || MARCH_Z196 && TUNE_DEFAULT
315
316config MARCH_ZEC12_TUNE
317 def_bool TUNE_ZEC12 || MARCH_ZEC12 && TUNE_DEFAULT
318
f8b2dcbd
MS
319config MARCH_Z13_TUNE
320 def_bool TUNE_Z13 || MARCH_Z13 && TUNE_DEFAULT
321
6997c323
MS
322config MARCH_Z14_TUNE
323 def_bool TUNE_Z14 || MARCH_Z14 && TUNE_DEFAULT
324
1db9e051
HC
325choice
326 prompt "Tune code generation"
327 default TUNE_DEFAULT
328 help
329 Cause the compiler to tune (-mtune) the generated code for a machine.
330 This will make the code run faster on the selected machine but
331 somewhat slower on other machines.
332 This option only changes how the compiler emits instructions, not the
333 selection of instructions itself, so the resulting kernel will run on
334 all other machines.
335
336config TUNE_DEFAULT
337 bool "Default"
338 help
339 Tune the generated code for the target processor for which the kernel
340 will be compiled.
341
1db9e051
HC
342config TUNE_Z900
343 bool "IBM zSeries model z800 and z900"
344
345config TUNE_Z990
346 bool "IBM zSeries model z890 and z990"
347
348config TUNE_Z9_109
349 bool "IBM System z9"
350
351config TUNE_Z10
352 bool "IBM System z10"
353
354config TUNE_Z196
355 bool "IBM zEnterprise 114 and 196"
356
357config TUNE_ZEC12
358 bool "IBM zBC12 and zEC12"
359
f8b2dcbd
MS
360config TUNE_Z13
361 bool "IBM z13"
362
6997c323
MS
363config TUNE_Z14
364 bool "IBM z14"
365
1db9e051
HC
366endchoice
367
347a8dc3 368config 64BIT
6f9a3c33 369 def_bool y
d9f7a745 370
843c48fd
JG
371config COMPAT
372 def_bool y
373 prompt "Kernel support for 31 bit emulation"
843c48fd
JG
374 select COMPAT_BINFMT_ELF if BINFMT_ELF
375 select ARCH_WANT_OLD_COMPAT_IPC
7eddd99c 376 select COMPAT_OLD_SIGACTION
2813893f 377 depends on MULTIUSER
843c48fd
JG
378 help
379 Select this option if you want to enable your system kernel to
380 handle system-calls from ELF binaries for 31 bit ESA. This option
381 (and some other stuff like libraries and such) is needed for
382 executing 31 bit applications. It is safe to say "Y".
383
384config SYSVIPC_COMPAT
385 def_bool y if COMPAT && SYSVIPC
386
1da177e4 387config SMP
6f9a3c33
MS
388 def_bool y
389 prompt "Symmetric multi-processing support"
1da177e4
LT
390 ---help---
391 This enables support for systems with more than one CPU. If you have
392 a system with only one CPU, like most personal computers, say N. If
393 you have a system with more than one CPU, say Y.
394
4a474157 395 If you say N here, the kernel will run on uni- and multiprocessor
1da177e4
LT
396 machines, but will use only one CPU of a multiprocessor machine. If
397 you say Y here, the kernel will run on many, but not all,
4a474157 398 uniprocessor machines. On a uniprocessor machine, the kernel
1da177e4
LT
399 will run faster if you say N here.
400
03502faa
AB
401 See also the SMP-HOWTO available at
402 <http://www.tldp.org/docs.html#howto>.
1da177e4
LT
403
404 Even if you don't know what to do here, say Y.
405
406config NR_CPUS
5c75a0da
HC
407 int "Maximum number of CPUs (2-512)"
408 range 2 512
1da177e4 409 depends on SMP
5a79859a 410 default "64"
1da177e4
LT
411 help
412 This allows you to specify the maximum number of CPUs which this
5c75a0da 413 kernel will support. The maximum supported value is 512 and the
1da177e4
LT
414 minimum value which makes sense is 2.
415
416 This is purely to save memory - each supported CPU adds
417 approximately sixteen kilobytes to the kernel image.
418
419config HOTPLUG_CPU
6f9a3c33
MS
420 def_bool y
421 prompt "Support for hot-pluggable CPUs"
1da177e4 422 depends on SMP
1da177e4
LT
423 help
424 Say Y here to be able to turn CPUs off and on. CPUs
425 can be controlled through /sys/devices/system/cpu/cpu#.
426 Say N if you want to disable CPU hotplug.
427
3a368f74
PH
428# Some NUMA nodes have memory ranges that span
429# other nodes. Even though a pfn is valid and
430# between a node's start and end pfns, it may not
431# reside on that node. See memmap_init_zone()
432# for details. <- They meant memory holes!
433config NODES_SPAN_OTHER_NODES
434 def_bool NUMA
435
436config NUMA
437 bool "NUMA support"
c095a949 438 depends on SMP && SCHED_TOPOLOGY
3a368f74
PH
439 default n
440 help
441 Enable NUMA support
442
443 This option adds NUMA support to the kernel.
444
445 An operation mode can be selected by appending
446 numa=<method> to the kernel command line.
447
448 The default behaviour is identical to appending numa=plain to
449 the command line. This will create just one node with all
450 available memory and all CPUs in it.
451
452config NODES_SHIFT
453 int "Maximum NUMA nodes (as a power of 2)"
454 range 1 10
455 depends on NUMA
456 default "4"
457 help
458 Specify the maximum number of NUMA nodes available on the target
459 system. Increases memory reserved to accommodate various tables.
460
c29a7baf
MH
461menu "Select NUMA modes"
462 depends on NUMA
463
464config NUMA_EMU
465 bool "NUMA emulation"
466 default y
467 help
468 Numa emulation mode will split the available system memory into
469 equal chunks which then are distributed over the configured number
470 of nodes in a round-robin manner.
471
472 The number of fake nodes is limited by the number of available memory
473 chunks (i.e. memory size / fake size) and the number of supported
474 nodes in the kernel.
475
476 The CPUs are assigned to the nodes in a way that partially respects
477 the original machine topology (if supported by the machine).
478 Fair distribution of the CPUs is not guaranteed.
479
480config EMU_SIZE
481 hex "NUMA emulation memory chunk size"
482 default 0x10000000
483 range 0x400000 0x100000000
484 depends on NUMA_EMU
485 help
486 Select the default size by which the memory is chopped and then
487 assigned to emulated NUMA nodes.
488
489 This can be overridden by specifying
490
491 emu_size=<n>
492
493 on the kernel command line where also suffixes K, M, G, and T are
494 supported.
495
496endmenu
9236b4dd
HC
497
498config SCHED_SMT
499 def_bool n
c29a7baf 500
8d11e021 501config SCHED_MC
83a24e32 502 def_bool n
8d11e021 503
4cb14bc8 504config SCHED_BOOK
10ad34bc
MS
505 def_bool n
506
adac0f1e
HC
507config SCHED_DRAWER
508 def_bool n
509
10ad34bc 510config SCHED_TOPOLOGY
6f9a3c33 511 def_bool y
10ad34bc 512 prompt "Topology scheduler support"
83a24e32 513 depends on SMP
10ad34bc 514 select SCHED_SMT
83a24e32 515 select SCHED_MC
10ad34bc 516 select SCHED_BOOK
adac0f1e 517 select SCHED_DRAWER
4cb14bc8 518 help
10ad34bc
MS
519 Topology scheduler support improves the CPU scheduler's decision
520 making when dealing with machines that have multi-threading,
521 multiple cores or multiple books.
4cb14bc8 522
843c48fd 523source kernel/Kconfig.hz
1da177e4 524
bdea9f6f
PR
525config KEXEC
526 def_bool y
527 select KEXEC_CORE
528
529config KEXEC_FILE
530 bool "kexec file based system call"
531 select KEXEC_CORE
532 select BUILD_BIN2C
533 depends on CRYPTO
534 depends on CRYPTO_SHA256
535 depends on CRYPTO_SHA256_S390
536 help
537 Enable the kexec file based system call. In contrast to the normal
538 kexec system call this system call takes file descriptors for the
539 kernel and initramfs as arguments.
540
541config ARCH_HAS_KEXEC_PURGATORY
542 def_bool y
543 depends on KEXEC_FILE
544
4c637cd8
HF
545config ARCH_RANDOM
546 def_bool y
547 prompt "s390 architectural random number generation API"
548 help
549 Enable the s390 architectural random number generation API
550 to provide random data for all consumers within the Linux
551 kernel.
552
553 When enabled the arch_random_* functions declared in linux/random.h
554 are implemented. The implementation is based on the s390 CPACF
555 instruction subfunction TRNG which provides a real true random
556 number generator.
557
558 If unsure, say Y.
559
d768bd89
MS
560config KERNEL_NOBP
561 def_bool n
562 prompt "Enable modified branch prediction for the kernel by default"
563 help
564 If this option is selected the kernel will switch to a modified
565 branch prediction mode if the firmware interface is available.
566 The modified branch prediction mode improves the behaviour in
567 regard to speculative execution.
568
569 With the option enabled the kernel parameter "nobp=0" or "nospec"
570 can be used to run the kernel in the normal branch prediction mode.
571
572 With the option disabled the modified branch prediction mode is
573 enabled with the "nobp=1" kernel parameter.
574
575 If unsure, say N.
576
f19fbd5e
MS
577config EXPOLINE
578 def_bool n
579 prompt "Avoid speculative indirect branches in the kernel"
580 help
581 Compile the kernel with the expoline compiler options to guard
582 against kernel-to-user data leaks by avoiding speculative indirect
583 branches.
584 Requires a compiler with -mindirect-branch=thunk support for full
585 protection. The kernel may run slower.
586
587 If unsure, say N.
588
589choice
590 prompt "Expoline default"
591 depends on EXPOLINE
592 default EXPOLINE_FULL
593
594config EXPOLINE_OFF
595 bool "spectre_v2=off"
596
6e179d64 597config EXPOLINE_AUTO
f19fbd5e
MS
598 bool "spectre_v2=auto"
599
600config EXPOLINE_FULL
601 bool "spectre_v2=on"
602
603endchoice
604
843c48fd 605endmenu
1da177e4 606
843c48fd 607menu "Memory setup"
1d057720 608
843c48fd 609config ARCH_SPARSEMEM_ENABLE
6f9a3c33 610 def_bool y
843c48fd
JG
611 select SPARSEMEM_VMEMMAP_ENABLE
612 select SPARSEMEM_VMEMMAP
e65e1fc2 613
843c48fd
JG
614config ARCH_SPARSEMEM_DEFAULT
615 def_bool y
1da177e4 616
843c48fd
JG
617config ARCH_SELECT_MEMORY_MODEL
618 def_bool y
1da177e4 619
843c48fd
JG
620config ARCH_ENABLE_MEMORY_HOTPLUG
621 def_bool y if SPARSEMEM
0efa4703 622
843c48fd
JG
623config ARCH_ENABLE_MEMORY_HOTREMOVE
624 def_bool y
e37f50e1 625
ec66ad66
MS
626config ARCH_ENABLE_SPLIT_PMD_PTLOCK
627 def_bool y
ec66ad66 628
843c48fd
JG
629config FORCE_MAX_ZONEORDER
630 int
631 default "9"
f861e405 632
b8402b95
HC
633config MAX_PHYSMEM_BITS
634 int "Maximum size of supported physical memory in bits (42-53)"
635 range 42 53
636 default "46"
637 help
638 This option specifies the maximum supported size of physical memory
639 in bits. Supported is any size between 2^42 (4TB) and 2^53 (8PB).
640 Increasing the number of bits also increases the kernel image size.
641 By default 46 bits (64TB) are supported.
642
1da177e4 643config PACK_STACK
6f9a3c33
MS
644 def_bool y
645 prompt "Pack kernel stack"
1da177e4
LT
646 help
647 This option enables the compiler option -mkernel-backchain if it
648 is available. If the option is available the compiler supports
649 the new stack layout which dramatically reduces the minimum stack
650 frame size. With an old compiler a non-leaf function needs a
651 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
652 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
653 and 24 byte on 64 bit.
654
655 Say Y if you are unsure.
656
1da177e4 657config CHECK_STACK
6f9a3c33 658 def_bool y
ce3dc447 659 depends on !VMAP_STACK
6f9a3c33 660 prompt "Detect kernel stack overflow"
1da177e4
LT
661 help
662 This option enables the compiler option -mstack-guard and
663 -mstack-size if they are available. If the compiler supports them
664 it will emit additional code to each function prolog to trigger
665 an illegal operation if the kernel stack is about to overflow.
666
667 Say N if you are unsure.
668
669config STACK_GUARD
670 int "Size of the guard area (128-1024)"
671 range 128 1024
672 depends on CHECK_STACK
673 default "256"
674 help
675 This allows you to specify the size of the guard area at the lower
676 end of the kernel stack. If the kernel stack points into the guard
677 area on function entry an illegal operation is triggered. The size
678 needs to be a power of 2. Please keep in mind that the size of an
679 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
680 The minimum size for the stack guard should be 256 for 31 bit and
681 512 for 64 bit.
682
2c190da4 683config WARN_DYNAMIC_STACK
6f9a3c33 684 def_bool n
2c190da4 685 prompt "Emit compiler warnings for function with dynamic stack usage"
1da177e4 686 help
2c190da4
JG
687 This option enables the compiler option -mwarn-dynamicstack. If the
688 compiler supports this options generates warnings for functions
689 that dynamically allocate stack space using alloca.
1da177e4
LT
690
691 Say N if you are unsure.
692
843c48fd 693endmenu
3f22ab27 694
843c48fd 695menu "I/O subsystem"
1da177e4 696
1da177e4 697config QDIO
6f9a3c33
MS
698 def_tristate y
699 prompt "QDIO support"
1da177e4 700 ---help---
8129ee16 701 This driver provides the Queued Direct I/O base support for
efca13bc 702 IBM System z.
1da177e4
LT
703
704 To compile this driver as a module, choose M here: the
705 module will be called qdio.
706
707 If unsure, say Y.
708
c8717a3d
JG
709menuconfig PCI
710 bool "PCI support"
c8717a3d 711 select PCI_MSI
a4ce5a48 712 select IOMMU_HELPER
8128f23c 713 select IOMMU_SUPPORT
f616ab59 714 select NEED_DMA_MAP_STATE
86596f0a 715 select NEED_SG_DMA_LENGTH
a4ce5a48 716
c8717a3d
JG
717 help
718 Enable PCI support.
719
720if PCI
721
722config PCI_NR_FUNCTIONS
723 int "Maximum number of PCI functions (1-4096)"
724 range 1 4096
b18601b0 725 default "128"
c8717a3d
JG
726 help
727 This allows you to specify the maximum number of PCI functions which
728 this kernel will support.
729
730source "drivers/pci/Kconfig"
c8717a3d
JG
731
732endif # PCI
733
734config PCI_DOMAINS
735 def_bool PCI
736
737config HAS_IOMEM
738 def_bool PCI
739
9d92a7e1 740config CHSC_SCH
d9c11b1e 741 def_tristate m
6f9a3c33 742 prompt "Support for CHSC subchannels"
9d92a7e1
CH
743 help
744 This driver allows usage of CHSC subchannels. A CHSC subchannel
745 is usually present on LPAR only.
746 The driver creates a device /dev/chsc, which may be used to
747 obtain I/O configuration information about the machine and
748 to issue asynchronous chsc commands (DANGEROUS).
749 You will usually only want to use this interface on a special
750 LPAR designated for system management.
751
752 To compile this driver as a module, choose M here: the
753 module will be called chsc_sch.
754
755 If unsure, say N.
756
1d1c8f78
SO
757config SCM_BUS
758 def_bool y
1d1c8f78
SO
759 prompt "SCM bus driver"
760 help
761 Bus driver for Storage Class Memory.
762
eadb86ab
SO
763config EADM_SCH
764 def_tristate m
765 prompt "Support for EADM subchannels"
766 depends on SCM_BUS
767 help
768 This driver allows usage of EADM subchannels. EADM subchannels act
769 as a communication vehicle for SCM increments.
770
771 To compile this driver as a module, choose M here: the
772 module will be called eadm_sch.
773
63f1934d
DJS
774config VFIO_CCW
775 def_tristate n
776 prompt "Support for VFIO-CCW subchannels"
84cd8fc4 777 depends on S390_CCW_IOMMU && VFIO_MDEV
63f1934d
DJS
778 help
779 This driver allows usage of I/O subchannels via VFIO-CCW.
780
781 To compile this driver as a module, choose M here: the
782 module will be called vfio_ccw.
783
1fde5734
TK
784config VFIO_AP
785 def_tristate n
786 prompt "VFIO support for AP devices"
787 depends on S390_AP_IOMMU && VFIO_MDEV_DEVICE && KVM
788 help
789 This driver grants access to Adjunct Processor (AP) devices
790 via the VFIO mediated device interface.
791
792 To compile this driver as a module, choose M here: the module
793 will be called vfio_ap.
794
843c48fd
JG
795endmenu
796
797menu "Dump support"
798
799config CRASH_DUMP
800 bool "kernel crash dumps"
5a79859a 801 depends on SMP
843c48fd
JG
802 select KEXEC
803 help
804 Generate crash dump after being started by kexec.
805 Crash dump kernels are loaded in the main kernel with kexec-tools
806 into a specially reserved region and then later executed after
807 a crash by kdump/kexec.
843c48fd 808 Refer to <file:Documentation/s390/zfcpdump.txt> for more details on this.
bf28a597
MH
809 This option also enables s390 zfcpdump.
810 See also <file:Documentation/s390/zfcpdump.txt>
843c48fd
JG
811
812endmenu
813
843c48fd
JG
814config SECCOMP
815 def_bool y
816 prompt "Enable seccomp to safely compute untrusted bytecode"
817 depends on PROC_FS
818 help
819 This kernel feature is useful for number crunching applications
820 that may need to compute untrusted bytecode during their
821 execution. By using pipes or other transports made available to
822 the process as file descriptors supporting the read/write
823 syscalls, it's possible to isolate those applications in
824 their own address space using seccomp. Once seccomp is
825 enabled via /proc/<pid>/seccomp, it cannot be disabled
826 and the task is only allowed to execute a few safe syscalls
827 defined by each seccomp mode.
828
829 If unsure, say Y.
830
843c48fd
JG
831menu "Power Management"
832
833config ARCH_HIBERNATION_POSSIBLE
5a79859a 834 def_bool y
843c48fd
JG
835
836source "kernel/power/Kconfig"
837
838endmenu
839
843c48fd
JG
840config PCMCIA
841 def_bool n
842
843config CCW
844 def_bool y
845
b6ef86e9
UB
846config HAVE_PNETID
847 tristate
848 default (SMC || CCWGROUP)
849
843c48fd 850menu "Virtualization"
684de39b 851
1da177e4 852config PFAULT
6f9a3c33
MS
853 def_bool y
854 prompt "Pseudo page fault support"
1da177e4
LT
855 help
856 Select this option, if you want to use PFAULT pseudo page fault
857 handling under VM. If running native or in LPAR, this option
858 has no effect. If your VM does not support PFAULT, PAGEEX
859 pseudo page fault handling will be used.
860 Note that VM 4.2 supports PFAULT but has a bug in its
861 implementation that causes some problems.
862 Everybody who wants to run Linux under VM != VM4.2 should select
863 this option.
864
1da177e4 865config CMM
6f9a3c33
MS
866 def_tristate n
867 prompt "Cooperative memory management"
1da177e4
LT
868 help
869 Select this option, if you want to enable the kernel interface
870 to reduce the memory size of the system. This is accomplished
871 by allocating pages of memory and put them "on hold". This only
872 makes sense for a system running under VM where the unused pages
873 will be reused by VM for other guest systems. The interface
874 allows an external monitor to balance memory of many systems.
875 Everybody who wants to run Linux under VM should select this
876 option.
877
1da177e4 878config CMM_IUCV
6f9a3c33
MS
879 def_bool y
880 prompt "IUCV special message interface to cooperative memory management"
1da177e4
LT
881 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
882 help
883 Select this option to enable the special message interface to
884 the cooperative memory management.
885
1da177e4 886config APPLDATA_BASE
6f9a3c33
MS
887 def_bool n
888 prompt "Linux - VM Monitor Stream, base infrastructure"
c185b783 889 depends on PROC_FS
1da177e4
LT
890 help
891 This provides a kernel interface for creating and updating z/VM APPLDATA
892 monitor records. The monitor records are updated at certain time
893 intervals, once the timer is started.
894 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
895 i.e. enables or disables monitoring on the Linux side.
896 A custom interval value (in seconds) can be written to
897 /proc/appldata/interval.
898
899 Defaults are 60 seconds interval and timer off.
900 The /proc entries can also be read from, showing the current settings.
901
902config APPLDATA_MEM
6f9a3c33
MS
903 def_tristate m
904 prompt "Monitor memory management statistics"
62fb2ba3 905 depends on APPLDATA_BASE && VM_EVENT_COUNTERS
1da177e4
LT
906 help
907 This provides memory management related data to the Linux - VM Monitor
908 Stream, like paging/swapping rate, memory utilisation, etc.
909 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
910 APPLDATA monitor record, i.e. enables or disables monitoring this record
911 on the z/VM side.
912
913 Default is disabled.
914 The /proc entry can also be read from, showing the current settings.
915
916 This can also be compiled as a module, which will be called
917 appldata_mem.o.
918
919config APPLDATA_OS
6f9a3c33
MS
920 def_tristate m
921 prompt "Monitor OS statistics"
1da177e4
LT
922 depends on APPLDATA_BASE
923 help
924 This provides OS related data to the Linux - VM Monitor Stream, like
925 CPU utilisation, etc.
926 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
927 APPLDATA monitor record, i.e. enables or disables monitoring this record
928 on the z/VM side.
929
930 Default is disabled.
931 This can also be compiled as a module, which will be called
932 appldata_os.o.
933
934config APPLDATA_NET_SUM
6f9a3c33
MS
935 def_tristate m
936 prompt "Monitor overall network statistics"
70193af9 937 depends on APPLDATA_BASE && NET
1da177e4
LT
938 help
939 This provides network related data to the Linux - VM Monitor Stream,
940 currently there is only a total sum of network I/O statistics, no
941 per-interface data.
942 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
943 APPLDATA monitor record, i.e. enables or disables monitoring this record
944 on the z/VM side.
945
946 Default is disabled.
947 This can also be compiled as a module, which will be called
948 appldata_net_sum.o.
949
24bbb1fa 950config S390_HYPFS_FS
6f9a3c33
MS
951 def_bool y
952 prompt "s390 hypervisor file system support"
24bbb1fa 953 select SYS_HYPERVISOR
24bbb1fa
MH
954 help
955 This is a virtual file system intended to provide accounting
956 information in an s390 hypervisor environment.
957
843c48fd 958source "arch/s390/kvm/Kconfig"
411ed322 959
fa587743 960config S390_GUEST
6f9a3c33 961 def_bool y
510cf5a6 962 prompt "s390 support for virtio devices"
79b6f7fb 963 select TTY
80629b0b 964 select VIRTUALIZATION
fa587743 965 select VIRTIO
faeba830 966 select VIRTIO_CONSOLE
fa587743 967 help
bdd1fc27
CH
968 Enabling this option adds support for virtio based paravirtual device
969 drivers on s390.
1da177e4 970
20766c08 971 Select this option if you want to run the kernel as a guest under
bdd1fc27 972 the KVM hypervisor.
155af2f9
HJP
973
974endmenu