summaryrefslogtreecommitdiff
path: root/arch/arm64/Kconfig
blob: 08f64b455aa8bf87f01b60233b4d89b38a8b6cb5 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
config ARM64
	def_bool y
	select ACPI_CCA_REQUIRED if ACPI
	select ACPI_GENERIC_GSI if ACPI
	select ACPI_REDUCED_HARDWARE_ONLY if ACPI
	select ARCH_HAS_DEVMEM_IS_ALLOWED
	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
	select ARCH_HAS_ELF_RANDOMIZE
	select ARCH_HAS_GCOV_PROFILE_ALL
	select ARCH_HAS_SG_CHAIN
	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
	select ARCH_USE_CMPXCHG_LOCKREF
	select ARCH_SUPPORTS_ATOMIC_RMW
	select ARCH_WANT_OPTIONAL_GPIOLIB
	select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
	select ARCH_WANT_FRAME_POINTERS
	select ARM_AMBA
	select ARM_ARCH_TIMER
	select ARM_GIC
	select AUDIT_ARCH_COMPAT_GENERIC
	select ARM_GIC_V2M if PCI_MSI
	select ARM_GIC_V3
	select ARM_GIC_V3_ITS if PCI_MSI
	select ARM_PSCI_FW
	select BUILDTIME_EXTABLE_SORT
	select CLONE_BACKWARDS
	select COMMON_CLK
	select CPU_PM if (SUSPEND || CPU_IDLE)
	select DCACHE_WORD_ACCESS
	select EDAC_SUPPORT
	select FRAME_POINTER
	select GENERIC_ALLOCATOR
	select GENERIC_CLOCKEVENTS
	select GENERIC_CLOCKEVENTS_BROADCAST
	select GENERIC_CPU_AUTOPROBE
	select GENERIC_EARLY_IOREMAP
	select GENERIC_IDLE_POLL_SETUP
	select GENERIC_IRQ_PROBE
	select GENERIC_IRQ_SHOW
	select GENERIC_IRQ_SHOW_LEVEL
	select GENERIC_PCI_IOMAP
	select GENERIC_SCHED_CLOCK
	select GENERIC_SMP_IDLE_THREAD
	select GENERIC_STRNCPY_FROM_USER
	select GENERIC_STRNLEN_USER
	select GENERIC_TIME_VSYSCALL
	select HANDLE_DOMAIN_IRQ
	select HARDIRQS_SW_RESEND
	select HAVE_ALIGNED_STRUCT_PAGE if SLUB
	select HAVE_ARCH_AUDITSYSCALL
	select HAVE_ARCH_BITREVERSE
	select HAVE_ARCH_JUMP_LABEL
	select HAVE_ARCH_KASAN if SPARSEMEM_VMEMMAP && !(ARM64_16K_PAGES && ARM64_VA_BITS_48)
	select HAVE_ARCH_KGDB
	select HAVE_ARCH_SECCOMP_FILTER
	select HAVE_ARCH_TRACEHOOK
	select HAVE_BPF_JIT
	select HAVE_C_RECORDMCOUNT
	select HAVE_CC_STACKPROTECTOR
	select HAVE_CMPXCHG_DOUBLE
	select HAVE_CMPXCHG_LOCAL
	select HAVE_DEBUG_BUGVERBOSE
	select HAVE_DEBUG_KMEMLEAK
	select HAVE_DMA_API_DEBUG
	select HAVE_DMA_ATTRS
	select HAVE_DMA_CONTIGUOUS
	select HAVE_DYNAMIC_FTRACE
	select HAVE_EFFICIENT_UNALIGNED_ACCESS
	select HAVE_FTRACE_MCOUNT_RECORD
	select HAVE_FUNCTION_TRACER
	select HAVE_FUNCTION_GRAPH_TRACER
	select HAVE_GENERIC_DMA_COHERENT
	select HAVE_HW_BREAKPOINT if PERF_EVENTS
	select HAVE_MEMBLOCK
	select HAVE_PATA_PLATFORM
	select HAVE_PERF_EVENTS
	select HAVE_PERF_REGS
	select HAVE_PERF_USER_STACK_DUMP
	select HAVE_RCU_TABLE_FREE
	select HAVE_SYSCALL_TRACEPOINTS
	select IOMMU_DMA if IOMMU_SUPPORT
	select IRQ_DOMAIN
	select IRQ_FORCED_THREADING
	select MODULES_USE_ELF_RELA
	select NO_BOOTMEM
	select OF
	select OF_EARLY_FLATTREE
	select OF_RESERVED_MEM
	select PERF_USE_VMALLOC
	select POWER_RESET
	select POWER_SUPPLY
	select RTC_LIB
	select SPARSE_IRQ
	select SYSCTL_EXCEPTION_TRACE
	select HAVE_CONTEXT_TRACKING
	help
	  ARM 64-bit (AArch64) Linux support.

config 64BIT
	def_bool y

config ARCH_PHYS_ADDR_T_64BIT
	def_bool y

config MMU
	def_bool y

config NO_IOPORT_MAP
	def_bool y if !PCI

config STACKTRACE_SUPPORT
	def_bool y

config ILLEGAL_POINTER_VALUE
	hex
	default 0xdead000000000000

config LOCKDEP_SUPPORT
	def_bool y

config TRACE_IRQFLAGS_SUPPORT
	def_bool y

config RWSEM_XCHGADD_ALGORITHM
	def_bool y

config GENERIC_BUG
	def_bool y
	depends on BUG

config GENERIC_BUG_RELATIVE_POINTERS
	def_bool y
	depends on GENERIC_BUG

config GENERIC_HWEIGHT
	def_bool y

config GENERIC_CSUM
        def_bool y

config GENERIC_CALIBRATE_DELAY
	def_bool y

config ZONE_DMA
	def_bool y

config HAVE_GENERIC_RCU_GUP
	def_bool y

config ARCH_DMA_ADDR_T_64BIT
	def_bool y

config NEED_DMA_MAP_STATE
	def_bool y

config NEED_SG_DMA_LENGTH
	def_bool y

config SMP
	def_bool y

config SWIOTLB
	def_bool y

config IOMMU_HELPER
	def_bool SWIOTLB

config KERNEL_MODE_NEON
	def_bool y

config FIX_EARLYCON_MEM
	def_bool y

config PGTABLE_LEVELS
	int
	default 2 if ARM64_16K_PAGES && ARM64_VA_BITS_36
	default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42
	default 3 if ARM64_64K_PAGES && ARM64_VA_BITS_48
	default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39
	default 3 if ARM64_16K_PAGES && ARM64_VA_BITS_47
	default 4 if !ARM64_64K_PAGES && ARM64_VA_BITS_48

source "init/Kconfig"

source "kernel/Kconfig.freezer"

source "arch/arm64/Kconfig.platforms"

menu "Bus support"

config PCI
	bool "PCI support"
	help
	  This feature enables support for PCI bus system. If you say Y
	  here, the kernel will include drivers and infrastructure code
	  to support PCI bus devices.

config PCI_DOMAINS
	def_bool PCI

config PCI_DOMAINS_GENERIC
	def_bool PCI

config PCI_SYSCALL
	def_bool PCI

source "drivers/pci/Kconfig"
source "drivers/pci/pcie/Kconfig"
source "drivers/pci/hotplug/Kconfig"

endmenu

menu "Kernel Features"

menu "ARM errata workarounds via the alternatives framework"

config ARM64_ERRATUM_826319
	bool "Cortex-A53: 826319: System might deadlock if a write cannot complete until read data is accepted"
	default y
	help
	  This option adds an alternative code sequence to work around ARM
	  erratum 826319 on Cortex-A53 parts up to r0p2 with an AMBA 4 ACE or
	  AXI master interface and an L2 cache.

	  If a Cortex-A53 uses an AMBA AXI4 ACE interface to other processors
	  and is unable to accept a certain write via this interface, it will
	  not progress on read data presented on the read data channel and the
	  system can deadlock.

	  The workaround promotes data cache clean instructions to
	  data cache clean-and-invalidate.
	  Please note that this does not necessarily enable the workaround,
	  as it depends on the alternative framework, which will only patch
	  the kernel if an affected CPU is detected.

	  If unsure, say Y.

config ARM64_ERRATUM_827319
	bool "Cortex-A53: 827319: Data cache clean instructions might cause overlapping transactions to the interconnect"
	default y
	help
	  This option adds an alternative code sequence to work around ARM
	  erratum 827319 on Cortex-A53 parts up to r0p2 with an AMBA 5 CHI
	  master interface and an L2 cache.

	  Under certain conditions this erratum can cause a clean line eviction
	  to occur at the same time as another transaction to the same address
	  on the AMBA 5 CHI interface, which can cause data corruption if the
	  interconnect reorders the two transactions.

	  The workaround promotes data cache clean instructions to
	  data cache clean-and-invalidate.
	  Please note that this does not necessarily enable the workaround,
	  as it depends on the alternative framework, which will only patch
	  the kernel if an affected CPU is detected.

	  If unsure, say Y.

config ARM64_ERRATUM_824069
	bool "Cortex-A53: 824069: Cache line might not be marked as clean after a CleanShared snoop"
	default y
	help
	  This option adds an alternative code sequence to work around ARM
	  erratum 824069 on Cortex-A53 parts up to r0p2 when it is connected
	  to a coherent interconnect.

	  If a Cortex-A53 processor is executing a store or prefetch for
	  write instruction at the same time as a processor in another
	  cluster is executing a cache maintenance operation to the same
	  address, then this erratum might cause a clean cache line to be
	  incorrectly marked as dirty.

	  The workaround promotes data cache clean instructions to
	  data cache clean-and-invalidate.
	  Please note that this option does not necessarily enable the
	  workaround, as it depends on the alternative framework, which will
	  only patch the kernel if an affected CPU is detected.

	  If unsure, say Y.

config ARM64_ERRATUM_819472
	bool "Cortex-A53: 819472: Store exclusive instructions might cause data corruption"
	default y
	help
	  This option adds an alternative code sequence to work around ARM
	  erratum 819472 on Cortex-A53 parts up to r0p1 with an L2 cache
	  present when it is connected to a coherent interconnect.

	  If the processor is executing a load and store exclusive sequence at
	  the same time as a processor in another cluster is executing a cache
	  maintenance operation to the same address, then this erratum might
	  cause data corruption.

	  The workaround promotes data cache clean instructions to
	  data cache clean-and-invalidate.
	  Please note that this does not necessarily enable the workaround,
	  as it depends on the alternative framework, which will only patch
	  the kernel if an affected CPU is detected.

	  If unsure, say Y.

config ARM64_ERRATUM_832075
	bool "Cortex-A57: 832075: possible deadlock on mixing exclusive memory accesses with device loads"
	default y
	help
	  This option adds an alternative code sequence to work around ARM
	  erratum 832075 on Cortex-A57 parts up to r1p2.

	  Affected Cortex-A57 parts might deadlock when exclusive load/store
	  instructions to Write-Back memory are mixed with Device loads.

	  The workaround is to promote device loads to use Load-Acquire
	  semantics.
	  Please note that this does not necessarily enable the workaround,
	  as it depends on the alternative framework, which will only patch
	  the kernel if an affected CPU is detected.

	  If unsure, say Y.

config ARM64_ERRATUM_834220
	bool "Cortex-A57: 834220: Stage 2 translation fault might be incorrectly reported in presence of a Stage 1 fault"
	depends on KVM
	default y
	help
	  This option adds an alternative code sequence to work around ARM
	  erratum 834220 on Cortex-A57 parts up to r1p2.

	  Affected Cortex-A57 parts might report a Stage 2 translation
	  fault as the result of a Stage 1 fault for load crossing a
	  page boundary when there is a permission or device memory
	  alignment fault at Stage 1 and a translation fault at Stage 2.

	  The workaround is to verify that the Stage 1 translation
	  doesn't generate a fault before handling the Stage 2 fault.
	  Please note that this does not necessarily enable the workaround,
	  as it depends on the alternative framework, which will only patch
	  the kernel if an affected CPU is detected.

	  If unsure, say Y.

config ARM64_ERRATUM_845719
	bool "Cortex-A53: 845719: a load might read incorrect data"
	depends on COMPAT
	default y
	help
	  This option adds an alternative code sequence to work around ARM
	  erratum 845719 on Cortex-A53 parts up to r0p4.

	  When running a compat (AArch32) userspace on an affected Cortex-A53
	  part, a load at EL0 from a virtual address that matches the bottom 32
	  bits of the virtual address used by a recent load at (AArch64) EL1
	  might return incorrect data.

	  The workaround is to write the contextidr_el1 register on exception
	  return to a 32-bit task.
	  Please note that this does not necessarily enable the workaround,
	  as it depends on the alternative framework, which will only patch
	  the kernel if an affected CPU is detected.

	  If unsure, say Y.

config ARM64_ERRATUM_843419
	bool "Cortex-A53: 843419: A load or store might access an incorrect address"
	depends on MODULES
	default y
	help
	  This option builds kernel modules using the large memory model in
	  order to avoid the use of the ADRP instruction, which can cause
	  a subsequent memory access to use an incorrect address on Cortex-A53
	  parts up to r0p4.

	  Note that the kernel itself must be linked with a version of ld
	  which fixes potentially affected ADRP instructions through the
	  use of veneers.

	  If unsure, say Y.

config CAVIUM_ERRATUM_22375
	bool "Cavium erratum 22375, 24313"
	default y
	help
	  Enable workaround for erratum 22375, 24313.

	  This implements two gicv3-its errata workarounds for ThunderX. Both
	  with small impact affecting only ITS table allocation.

	    erratum 22375: only alloc 8MB table size
	    erratum 24313: ignore memory access type

	  The fixes are in ITS initialization and basically ignore memory access
	  type and table size provided by the TYPER and BASER registers.

	  If unsure, say Y.

config CAVIUM_ERRATUM_23154
	bool "Cavium erratum 23154: Access to ICC_IAR1_EL1 is not sync'ed"
	default y
	help
	  The gicv3 of ThunderX requires a modified version for
	  reading the IAR status to ensure data synchronization
	  (access to icc_iar1_el1 is not sync'ed before and after).

	  If unsure, say Y.

endmenu


choice
	prompt "Page size"
	default ARM64_4K_PAGES
	help
	  Page size (translation granule) configuration.

config ARM64_4K_PAGES
	bool "4KB"
	help
	  This feature enables 4KB pages support.

config ARM64_16K_PAGES
	bool "16KB"
	help
	  The system will use 16KB pages support. AArch32 emulation
	  requires applications compiled with 16K (or a multiple of 16K)
	  aligned segments.

config ARM64_64K_PAGES
	bool "64KB"
	help
	  This feature enables 64KB pages support (4KB by default)
	  allowing only two levels of page tables and faster TLB
	  look-up. AArch32 emulation requires applications compiled
	  with 64K aligned segments.

endchoice

choice
	prompt "Virtual address space size"
	default ARM64_VA_BITS_39 if ARM64_4K_PAGES
	default ARM64_VA_BITS_47 if ARM64_16K_PAGES
	default ARM64_VA_BITS_42 if ARM64_64K_PAGES
	help
	  Allows choosing one of multiple possible virtual address
	  space sizes. The level of translation table is determined by
	  a combination of page size and virtual address space size.

config ARM64_VA_BITS_36
	bool "36-bit" if EXPERT
	depends on ARM64_16K_PAGES

config ARM64_VA_BITS_39
	bool "39-bit"
	depends on ARM64_4K_PAGES

config ARM64_VA_BITS_42
	bool "42-bit"
	depends on ARM64_64K_PAGES

config ARM64_VA_BITS_47
	bool "47-bit"
	depends on ARM64_16K_PAGES

config ARM64_VA_BITS_48
	bool "48-bit"

endchoice

config ARM64_VA_BITS
	int
	default 36 if ARM64_VA_BITS_36
	default 39 if ARM64_VA_BITS_39
	default 42 if ARM64_VA_BITS_42
	default 47 if ARM64_VA_BITS_47
	default 48 if ARM64_VA_BITS_48

config CPU_BIG_ENDIAN
       bool "Build big-endian kernel"
       help
         Say Y if you plan on running a kernel in big-endian mode.

config SCHED_MC
	bool "Multi-core scheduler support"
	help
	  Multi-core scheduler support improves the CPU scheduler's decision
	  making when dealing with multi-core CPU chips at a cost of slightly
	  increased overhead in some places. If unsure say N here.

config SCHED_SMT
	bool "SMT scheduler support"
	help
	  Improves the CPU scheduler's decision making when dealing with
	  MultiThreading at a cost of slightly increased overhead in some
	  places. If unsure say N here.

config NR_CPUS
	int "Maximum number of CPUs (2-4096)"
	range 2 4096
	# These have to remain sorted largest to smallest
	default "64"

config HOTPLUG_CPU
	bool "Support for hot-pluggable CPUs"
	select GENERIC_IRQ_MIGRATION
	help
	  Say Y here to experiment with turning CPUs off and on.  CPUs
	  can be controlled through /sys/devices/system/cpu.

source kernel/Kconfig.preempt
source kernel/Kconfig.hz

config ARCH_HAS_HOLES_MEMORYMODEL
	def_bool y if SPARSEMEM

config ARCH_SPARSEMEM_ENABLE
	def_bool y
	select SPARSEMEM_VMEMMAP_ENABLE

config ARCH_SPARSEMEM_DEFAULT
	def_bool ARCH_SPARSEMEM_ENABLE

config ARCH_SELECT_MEMORY_MODEL
	def_bool ARCH_SPARSEMEM_ENABLE

config HAVE_ARCH_PFN_VALID
	def_bool ARCH_HAS_HOLES_MEMORYMODEL || !SPARSEMEM

config HW_PERF_EVENTS
	def_bool y
	depends on ARM_PMU

config SYS_SUPPORTS_HUGETLBFS
	def_bool y

config ARCH_WANT_GENERAL_HUGETLB
	def_bool y

config ARCH_WANT_HUGE_PMD_SHARE
	def_bool y if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)

config HAVE_ARCH_TRANSPARENT_HUGEPAGE
	def_bool y

config ARCH_HAS_CACHE_LINE_SIZE
	def_bool y

source "mm/Kconfig"

config SECCOMP
	bool "Enable seccomp to safely compute untrusted bytecode"
	---help---
	  This kernel feature is useful for number crunching applications
	  that may need to compute untrusted bytecode during their
	  execution. By using pipes or other transports made available to
	  the process as file descriptors supporting the read/write
	  syscalls, it's possible to isolate those applications in
	  their own address space using seccomp. Once seccomp is
	  enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
	  and the task is only allowed to execute a few safe syscalls
	  defined by each seccomp mode.

config XEN_DOM0
	def_bool y
	depends on XEN

config XEN
	bool "Xen guest support on ARM64"
	depends on ARM64 && OF
	select SWIOTLB_XEN
	help
	  Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64.

config FORCE_MAX_ZONEORDER
	int
	default "14" if (ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE)
	default "12" if (ARM64_16K_PAGES && TRANSPARENT_HUGEPAGE)
	default "11"
	help
	  The kernel memory allocator divides physically contiguous memory
	  blocks into "zones", where each zone is a power of two number of
	  pages.  This option selects the largest power of two that the kernel
	  keeps in the memory allocator.  If you need to allocate very large
	  blocks of physically contiguous memory, then you may need to
	  increase this value.

	  This config option is actually maximum order plus one. For example,
	  a value of 11 means that the largest free memory block is 2^10 pages.

	  We make sure that we can allocate upto a HugePage size for each configuration.
	  Hence we have :
		MAX_ORDER = (PMD_SHIFT - PAGE_SHIFT) + 1 => PAGE_SHIFT - 2

	  However for 4K, we choose a higher default value, 11 as opposed to 10, giving us
	  4M allocations matching the default size used by generic code.

menuconfig ARMV8_DEPRECATED
	bool "Emulate deprecated/obsolete ARMv8 instructions"
	depends on COMPAT
	help
	  Legacy software support may require certain instructions
	  that have been deprecated or obsoleted in the architecture.

	  Enable this config to enable selective emulation of these
	  features.

	  If unsure, say Y

if ARMV8_DEPRECATED

config SWP_EMULATION
	bool "Emulate SWP/SWPB instructions"
	help
	  ARMv8 obsoletes the use of A32 SWP/SWPB instructions such that
	  they are always undefined. Say Y here to enable software
	  emulation of these instructions for userspace using LDXR/STXR.

	  In some older versions of glibc [<=2.8] SWP is used during futex
	  trylock() operations with the assumption that the code will not
	  be preempted. This invalid assumption may be more likely to fail
	  with SWP emulation enabled, leading to deadlock of the user
	  application.

	  NOTE: when accessing uncached shared regions, LDXR/STXR rely
	  on an external transaction monitoring block called a global
	  monitor to maintain update atomicity. If your system does not
	  implement a global monitor, this option can cause programs that
	  perform SWP operations to uncached memory to deadlock.

	  If unsure, say Y

config CP15_BARRIER_EMULATION
	bool "Emulate CP15 Barrier instructions"
	help
	  The CP15 barrier instructions - CP15ISB, CP15DSB, and
	  CP15DMB - are deprecated in ARMv8 (and ARMv7). It is
	  strongly recommended to use the ISB, DSB, and DMB
	  instructions instead.

	  Say Y here to enable software emulation of these
	  instructions for AArch32 userspace code. When this option is
	  enabled, CP15 barrier usage is traced which can help
	  identify software that needs updating.

	  If unsure, say Y

config SETEND_EMULATION
	bool "Emulate SETEND instruction"
	help
	  The SETEND instruction alters the data-endianness of the
	  AArch32 EL0, and is deprecated in ARMv8.

	  Say Y here to enable software emulation of the instruction
	  for AArch32 userspace code.

	  Note: All the cpus on the system must have mixed endian support at EL0
	  for this feature to be enabled. If a new CPU - which doesn't support mixed
	  endian - is hotplugged in after this feature has been enabled, there could
	  be unexpected results in the applications.

	  If unsure, say Y
endif

menu "ARMv8.1 architectural features"

config ARM64_HW_AFDBM
	bool "Support for hardware updates of the Access and Dirty page flags"
	default y
	help
	  The ARMv8.1 architecture extensions introduce support for
	  hardware updates of the access and dirty information in page
	  table entries. When enabled in TCR_EL1 (HA and HD bits) on
	  capable processors, accesses to pages with PTE_AF cleared will
	  set this bit instead of raising an access flag fault.
	  Similarly, writes to read-only pages with the DBM bit set will
	  clear the read-only bit (AP[2]) instead of raising a
	  permission fault.

	  Kernels built with this configuration option enabled continue
	  to work on pre-ARMv8.1 hardware and the performance impact is
	  minimal. If unsure, say Y.

config ARM64_PAN
	bool "Enable support for Privileged Access Never (PAN)"
	default y
	help
	 Privileged Access Never (PAN; part of the ARMv8.1 Extensions)
	 prevents the kernel or hypervisor from accessing user-space (EL0)
	 memory directly.

	 Choosing this option will cause any unprotected (not using
	 copy_to_user et al) memory access to fail with a permission fault.

	 The feature is detected at runtime, and will remain as a 'nop'
	 instruction if the cpu does not implement the feature.

config ARM64_LSE_ATOMICS
	bool "Atomic instructions"
	help
	  As part of the Large System Extensions, ARMv8.1 introduces new
	  atomic instructions that are designed specifically to scale in
	  very large systems.

	  Say Y here to make use of these instructions for the in-kernel
	  atomic routines. This incurs a small overhead on CPUs that do
	  not support these instructions and requires the kernel to be
	  built with binutils >= 2.25.

endmenu

endmenu

menu "Boot options"

config CMDLINE
	string "Default kernel command string"
	default ""
	help
	  Provide a set of default command-line options at build time by
	  entering them here. As a minimum, you should specify the the
	  root device (e.g. root=/dev/nfs).

config CMDLINE_FORCE
	bool "Always use the default kernel command string"
	help
	  Always use the default kernel command string, even if the boot
	  loader passes other arguments to the kernel.
	  This is useful if you cannot or don't want to change the
	  command-line options your boot loader passes to the kernel.

config EFI_STUB
	bool

config EFI
	bool "UEFI runtime support"
	depends on OF && !CPU_BIG_ENDIAN
	select LIBFDT
	select UCS2_STRING
	select EFI_PARAMS_FROM_FDT
	select EFI_RUNTIME_WRAPPERS
	select EFI_STUB
	select EFI_ARMSTUB
	default y
	help
	  This option provides support for runtime services provided
	  by UEFI firmware (such as non-volatile variables, realtime
          clock, and platform reset). A UEFI stub is also provided to
	  allow the kernel to be booted as an EFI application. This
	  is only useful on systems that have UEFI firmware.

config DMI
	bool "Enable support for SMBIOS (DMI) tables"
	depends on EFI
	default y
	help
	  This enables SMBIOS/DMI feature for systems.

	  This option is only useful on systems that have UEFI firmware.
	  However, even with this option, the resultant kernel should
	  continue to boot on existing non-UEFI platforms.

endmenu

menu "Userspace binary formats"

source "fs/Kconfig.binfmt"

config COMPAT
	bool "Kernel support for 32-bit EL0"
	depends on ARM64_4K_PAGES || EXPERT
	select COMPAT_BINFMT_ELF
	select HAVE_UID16
	select OLD_SIGSUSPEND3
	select COMPAT_OLD_SIGACTION
	help
	  This option enables support for a 32-bit EL0 running under a 64-bit
	  kernel at EL1. AArch32-specific components such as system calls,
	  the user helper functions, VFP support and the ptrace interface are
	  handled appropriately by the kernel.

	  If you use a page size other than 4KB (i.e, 16KB or 64KB), please be aware
	  that you will only be able to execute AArch32 binaries that were compiled
	  with page size aligned segments.

	  If you want to execute 32-bit userspace applications, say Y.

config SYSVIPC_COMPAT
	def_bool y
	depends on COMPAT && SYSVIPC

endmenu

menu "Power management options"

source "kernel/power/Kconfig"

config ARCH_SUSPEND_POSSIBLE
	def_bool y

endmenu

menu "CPU Power Management"

source "drivers/cpuidle/Kconfig"

source "drivers/cpufreq/Kconfig"

endmenu

source "net/Kconfig"

source "drivers/Kconfig"

source "drivers/firmware/Kconfig"

source "drivers/acpi/Kconfig"

source "fs/Kconfig"

source "arch/arm64/kvm/Kconfig"

source "arch/arm64/Kconfig.debug"

source "security/Kconfig"

source "crypto/Kconfig"
if CRYPTO
source "arch/arm64/crypto/Kconfig"
endif

source "lib/Kconfig"