arm: mm: support ARCH_MMAP_RND_BITS
[linux-2.6-block.git] / arch / arm64 / Kconfig
... / ...
CommitLineData
1config ARM64
2 def_bool y
3 select ACPI_CCA_REQUIRED if ACPI
4 select ACPI_GENERIC_GSI if ACPI
5 select ACPI_REDUCED_HARDWARE_ONLY if ACPI
6 select ARCH_HAS_DEVMEM_IS_ALLOWED
7 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
8 select ARCH_HAS_ELF_RANDOMIZE
9 select ARCH_HAS_GCOV_PROFILE_ALL
10 select ARCH_HAS_SG_CHAIN
11 select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
12 select ARCH_USE_CMPXCHG_LOCKREF
13 select ARCH_SUPPORTS_ATOMIC_RMW
14 select ARCH_WANT_OPTIONAL_GPIOLIB
15 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
16 select ARCH_WANT_FRAME_POINTERS
17 select ARM_AMBA
18 select ARM_ARCH_TIMER
19 select ARM_GIC
20 select AUDIT_ARCH_COMPAT_GENERIC
21 select ARM_GIC_V2M if PCI_MSI
22 select ARM_GIC_V3
23 select ARM_GIC_V3_ITS if PCI_MSI
24 select ARM_PSCI_FW
25 select BUILDTIME_EXTABLE_SORT
26 select CLONE_BACKWARDS
27 select COMMON_CLK
28 select CPU_PM if (SUSPEND || CPU_IDLE)
29 select DCACHE_WORD_ACCESS
30 select EDAC_SUPPORT
31 select FRAME_POINTER
32 select GENERIC_ALLOCATOR
33 select GENERIC_CLOCKEVENTS
34 select GENERIC_CLOCKEVENTS_BROADCAST
35 select GENERIC_CPU_AUTOPROBE
36 select GENERIC_EARLY_IOREMAP
37 select GENERIC_IDLE_POLL_SETUP
38 select GENERIC_IRQ_PROBE
39 select GENERIC_IRQ_SHOW
40 select GENERIC_IRQ_SHOW_LEVEL
41 select GENERIC_PCI_IOMAP
42 select GENERIC_SCHED_CLOCK
43 select GENERIC_SMP_IDLE_THREAD
44 select GENERIC_STRNCPY_FROM_USER
45 select GENERIC_STRNLEN_USER
46 select GENERIC_TIME_VSYSCALL
47 select HANDLE_DOMAIN_IRQ
48 select HARDIRQS_SW_RESEND
49 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
50 select HAVE_ARCH_AUDITSYSCALL
51 select HAVE_ARCH_BITREVERSE
52 select HAVE_ARCH_JUMP_LABEL
53 select HAVE_ARCH_KASAN if SPARSEMEM_VMEMMAP && !(ARM64_16K_PAGES && ARM64_VA_BITS_48)
54 select HAVE_ARCH_KGDB
55 select HAVE_ARCH_SECCOMP_FILTER
56 select HAVE_ARCH_TRACEHOOK
57 select HAVE_BPF_JIT
58 select HAVE_C_RECORDMCOUNT
59 select HAVE_CC_STACKPROTECTOR
60 select HAVE_CMPXCHG_DOUBLE
61 select HAVE_CMPXCHG_LOCAL
62 select HAVE_DEBUG_BUGVERBOSE
63 select HAVE_DEBUG_KMEMLEAK
64 select HAVE_DMA_API_DEBUG
65 select HAVE_DMA_ATTRS
66 select HAVE_DMA_CONTIGUOUS
67 select HAVE_DYNAMIC_FTRACE
68 select HAVE_EFFICIENT_UNALIGNED_ACCESS
69 select HAVE_FTRACE_MCOUNT_RECORD
70 select HAVE_FUNCTION_TRACER
71 select HAVE_FUNCTION_GRAPH_TRACER
72 select HAVE_GENERIC_DMA_COHERENT
73 select HAVE_HW_BREAKPOINT if PERF_EVENTS
74 select HAVE_IRQ_TIME_ACCOUNTING
75 select HAVE_MEMBLOCK
76 select HAVE_PATA_PLATFORM
77 select HAVE_PERF_EVENTS
78 select HAVE_PERF_REGS
79 select HAVE_PERF_USER_STACK_DUMP
80 select HAVE_RCU_TABLE_FREE
81 select HAVE_SYSCALL_TRACEPOINTS
82 select IOMMU_DMA if IOMMU_SUPPORT
83 select IRQ_DOMAIN
84 select IRQ_FORCED_THREADING
85 select MODULES_USE_ELF_RELA
86 select NO_BOOTMEM
87 select OF
88 select OF_EARLY_FLATTREE
89 select OF_RESERVED_MEM
90 select PERF_USE_VMALLOC
91 select POWER_RESET
92 select POWER_SUPPLY
93 select RTC_LIB
94 select SPARSE_IRQ
95 select SYSCTL_EXCEPTION_TRACE
96 select HAVE_CONTEXT_TRACKING
97 select HAVE_ARM_SMCCC
98 help
99 ARM 64-bit (AArch64) Linux support.
100
101config 64BIT
102 def_bool y
103
104config ARCH_PHYS_ADDR_T_64BIT
105 def_bool y
106
107config MMU
108 def_bool y
109
110config NO_IOPORT_MAP
111 def_bool y if !PCI
112
113config STACKTRACE_SUPPORT
114 def_bool y
115
116config ILLEGAL_POINTER_VALUE
117 hex
118 default 0xdead000000000000
119
120config LOCKDEP_SUPPORT
121 def_bool y
122
123config TRACE_IRQFLAGS_SUPPORT
124 def_bool y
125
126config RWSEM_XCHGADD_ALGORITHM
127 def_bool y
128
129config GENERIC_BUG
130 def_bool y
131 depends on BUG
132
133config GENERIC_BUG_RELATIVE_POINTERS
134 def_bool y
135 depends on GENERIC_BUG
136
137config GENERIC_HWEIGHT
138 def_bool y
139
140config GENERIC_CSUM
141 def_bool y
142
143config GENERIC_CALIBRATE_DELAY
144 def_bool y
145
146config ZONE_DMA
147 def_bool y
148
149config HAVE_GENERIC_RCU_GUP
150 def_bool y
151
152config ARCH_DMA_ADDR_T_64BIT
153 def_bool y
154
155config NEED_DMA_MAP_STATE
156 def_bool y
157
158config NEED_SG_DMA_LENGTH
159 def_bool y
160
161config SMP
162 def_bool y
163
164config SWIOTLB
165 def_bool y
166
167config IOMMU_HELPER
168 def_bool SWIOTLB
169
170config KERNEL_MODE_NEON
171 def_bool y
172
173config FIX_EARLYCON_MEM
174 def_bool y
175
176config PGTABLE_LEVELS
177 int
178 default 2 if ARM64_16K_PAGES && ARM64_VA_BITS_36
179 default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42
180 default 3 if ARM64_64K_PAGES && ARM64_VA_BITS_48
181 default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39
182 default 3 if ARM64_16K_PAGES && ARM64_VA_BITS_47
183 default 4 if !ARM64_64K_PAGES && ARM64_VA_BITS_48
184
185source "init/Kconfig"
186
187source "kernel/Kconfig.freezer"
188
189source "arch/arm64/Kconfig.platforms"
190
191menu "Bus support"
192
193config PCI
194 bool "PCI support"
195 help
196 This feature enables support for PCI bus system. If you say Y
197 here, the kernel will include drivers and infrastructure code
198 to support PCI bus devices.
199
200config PCI_DOMAINS
201 def_bool PCI
202
203config PCI_DOMAINS_GENERIC
204 def_bool PCI
205
206config PCI_SYSCALL
207 def_bool PCI
208
209source "drivers/pci/Kconfig"
210source "drivers/pci/pcie/Kconfig"
211source "drivers/pci/hotplug/Kconfig"
212
213endmenu
214
215menu "Kernel Features"
216
217menu "ARM errata workarounds via the alternatives framework"
218
219config ARM64_ERRATUM_826319
220 bool "Cortex-A53: 826319: System might deadlock if a write cannot complete until read data is accepted"
221 default y
222 help
223 This option adds an alternative code sequence to work around ARM
224 erratum 826319 on Cortex-A53 parts up to r0p2 with an AMBA 4 ACE or
225 AXI master interface and an L2 cache.
226
227 If a Cortex-A53 uses an AMBA AXI4 ACE interface to other processors
228 and is unable to accept a certain write via this interface, it will
229 not progress on read data presented on the read data channel and the
230 system can deadlock.
231
232 The workaround promotes data cache clean instructions to
233 data cache clean-and-invalidate.
234 Please note that this does not necessarily enable the workaround,
235 as it depends on the alternative framework, which will only patch
236 the kernel if an affected CPU is detected.
237
238 If unsure, say Y.
239
240config ARM64_ERRATUM_827319
241 bool "Cortex-A53: 827319: Data cache clean instructions might cause overlapping transactions to the interconnect"
242 default y
243 help
244 This option adds an alternative code sequence to work around ARM
245 erratum 827319 on Cortex-A53 parts up to r0p2 with an AMBA 5 CHI
246 master interface and an L2 cache.
247
248 Under certain conditions this erratum can cause a clean line eviction
249 to occur at the same time as another transaction to the same address
250 on the AMBA 5 CHI interface, which can cause data corruption if the
251 interconnect reorders the two transactions.
252
253 The workaround promotes data cache clean instructions to
254 data cache clean-and-invalidate.
255 Please note that this does not necessarily enable the workaround,
256 as it depends on the alternative framework, which will only patch
257 the kernel if an affected CPU is detected.
258
259 If unsure, say Y.
260
261config ARM64_ERRATUM_824069
262 bool "Cortex-A53: 824069: Cache line might not be marked as clean after a CleanShared snoop"
263 default y
264 help
265 This option adds an alternative code sequence to work around ARM
266 erratum 824069 on Cortex-A53 parts up to r0p2 when it is connected
267 to a coherent interconnect.
268
269 If a Cortex-A53 processor is executing a store or prefetch for
270 write instruction at the same time as a processor in another
271 cluster is executing a cache maintenance operation to the same
272 address, then this erratum might cause a clean cache line to be
273 incorrectly marked as dirty.
274
275 The workaround promotes data cache clean instructions to
276 data cache clean-and-invalidate.
277 Please note that this option does not necessarily enable the
278 workaround, as it depends on the alternative framework, which will
279 only patch the kernel if an affected CPU is detected.
280
281 If unsure, say Y.
282
283config ARM64_ERRATUM_819472
284 bool "Cortex-A53: 819472: Store exclusive instructions might cause data corruption"
285 default y
286 help
287 This option adds an alternative code sequence to work around ARM
288 erratum 819472 on Cortex-A53 parts up to r0p1 with an L2 cache
289 present when it is connected to a coherent interconnect.
290
291 If the processor is executing a load and store exclusive sequence at
292 the same time as a processor in another cluster is executing a cache
293 maintenance operation to the same address, then this erratum might
294 cause data corruption.
295
296 The workaround promotes data cache clean instructions to
297 data cache clean-and-invalidate.
298 Please note that this does not necessarily enable the workaround,
299 as it depends on the alternative framework, which will only patch
300 the kernel if an affected CPU is detected.
301
302 If unsure, say Y.
303
304config ARM64_ERRATUM_832075
305 bool "Cortex-A57: 832075: possible deadlock on mixing exclusive memory accesses with device loads"
306 default y
307 help
308 This option adds an alternative code sequence to work around ARM
309 erratum 832075 on Cortex-A57 parts up to r1p2.
310
311 Affected Cortex-A57 parts might deadlock when exclusive load/store
312 instructions to Write-Back memory are mixed with Device loads.
313
314 The workaround is to promote device loads to use Load-Acquire
315 semantics.
316 Please note that this does not necessarily enable the workaround,
317 as it depends on the alternative framework, which will only patch
318 the kernel if an affected CPU is detected.
319
320 If unsure, say Y.
321
322config ARM64_ERRATUM_834220
323 bool "Cortex-A57: 834220: Stage 2 translation fault might be incorrectly reported in presence of a Stage 1 fault"
324 depends on KVM
325 default y
326 help
327 This option adds an alternative code sequence to work around ARM
328 erratum 834220 on Cortex-A57 parts up to r1p2.
329
330 Affected Cortex-A57 parts might report a Stage 2 translation
331 fault as the result of a Stage 1 fault for load crossing a
332 page boundary when there is a permission or device memory
333 alignment fault at Stage 1 and a translation fault at Stage 2.
334
335 The workaround is to verify that the Stage 1 translation
336 doesn't generate a fault before handling the Stage 2 fault.
337 Please note that this does not necessarily enable the workaround,
338 as it depends on the alternative framework, which will only patch
339 the kernel if an affected CPU is detected.
340
341 If unsure, say Y.
342
343config ARM64_ERRATUM_845719
344 bool "Cortex-A53: 845719: a load might read incorrect data"
345 depends on COMPAT
346 default y
347 help
348 This option adds an alternative code sequence to work around ARM
349 erratum 845719 on Cortex-A53 parts up to r0p4.
350
351 When running a compat (AArch32) userspace on an affected Cortex-A53
352 part, a load at EL0 from a virtual address that matches the bottom 32
353 bits of the virtual address used by a recent load at (AArch64) EL1
354 might return incorrect data.
355
356 The workaround is to write the contextidr_el1 register on exception
357 return to a 32-bit task.
358 Please note that this does not necessarily enable the workaround,
359 as it depends on the alternative framework, which will only patch
360 the kernel if an affected CPU is detected.
361
362 If unsure, say Y.
363
364config ARM64_ERRATUM_843419
365 bool "Cortex-A53: 843419: A load or store might access an incorrect address"
366 depends on MODULES
367 default y
368 help
369 This option builds kernel modules using the large memory model in
370 order to avoid the use of the ADRP instruction, which can cause
371 a subsequent memory access to use an incorrect address on Cortex-A53
372 parts up to r0p4.
373
374 Note that the kernel itself must be linked with a version of ld
375 which fixes potentially affected ADRP instructions through the
376 use of veneers.
377
378 If unsure, say Y.
379
380config CAVIUM_ERRATUM_22375
381 bool "Cavium erratum 22375, 24313"
382 default y
383 help
384 Enable workaround for erratum 22375, 24313.
385
386 This implements two gicv3-its errata workarounds for ThunderX. Both
387 with small impact affecting only ITS table allocation.
388
389 erratum 22375: only alloc 8MB table size
390 erratum 24313: ignore memory access type
391
392 The fixes are in ITS initialization and basically ignore memory access
393 type and table size provided by the TYPER and BASER registers.
394
395 If unsure, say Y.
396
397config CAVIUM_ERRATUM_23154
398 bool "Cavium erratum 23154: Access to ICC_IAR1_EL1 is not sync'ed"
399 default y
400 help
401 The gicv3 of ThunderX requires a modified version for
402 reading the IAR status to ensure data synchronization
403 (access to icc_iar1_el1 is not sync'ed before and after).
404
405 If unsure, say Y.
406
407endmenu
408
409
410choice
411 prompt "Page size"
412 default ARM64_4K_PAGES
413 help
414 Page size (translation granule) configuration.
415
416config ARM64_4K_PAGES
417 bool "4KB"
418 help
419 This feature enables 4KB pages support.
420
421config ARM64_16K_PAGES
422 bool "16KB"
423 help
424 The system will use 16KB pages support. AArch32 emulation
425 requires applications compiled with 16K (or a multiple of 16K)
426 aligned segments.
427
428config ARM64_64K_PAGES
429 bool "64KB"
430 help
431 This feature enables 64KB pages support (4KB by default)
432 allowing only two levels of page tables and faster TLB
433 look-up. AArch32 emulation requires applications compiled
434 with 64K aligned segments.
435
436endchoice
437
438choice
439 prompt "Virtual address space size"
440 default ARM64_VA_BITS_39 if ARM64_4K_PAGES
441 default ARM64_VA_BITS_47 if ARM64_16K_PAGES
442 default ARM64_VA_BITS_42 if ARM64_64K_PAGES
443 help
444 Allows choosing one of multiple possible virtual address
445 space sizes. The level of translation table is determined by
446 a combination of page size and virtual address space size.
447
448config ARM64_VA_BITS_36
449 bool "36-bit" if EXPERT
450 depends on ARM64_16K_PAGES
451
452config ARM64_VA_BITS_39
453 bool "39-bit"
454 depends on ARM64_4K_PAGES
455
456config ARM64_VA_BITS_42
457 bool "42-bit"
458 depends on ARM64_64K_PAGES
459
460config ARM64_VA_BITS_47
461 bool "47-bit"
462 depends on ARM64_16K_PAGES
463
464config ARM64_VA_BITS_48
465 bool "48-bit"
466
467endchoice
468
469config ARM64_VA_BITS
470 int
471 default 36 if ARM64_VA_BITS_36
472 default 39 if ARM64_VA_BITS_39
473 default 42 if ARM64_VA_BITS_42
474 default 47 if ARM64_VA_BITS_47
475 default 48 if ARM64_VA_BITS_48
476
477config CPU_BIG_ENDIAN
478 bool "Build big-endian kernel"
479 help
480 Say Y if you plan on running a kernel in big-endian mode.
481
482config SCHED_MC
483 bool "Multi-core scheduler support"
484 help
485 Multi-core scheduler support improves the CPU scheduler's decision
486 making when dealing with multi-core CPU chips at a cost of slightly
487 increased overhead in some places. If unsure say N here.
488
489config SCHED_SMT
490 bool "SMT scheduler support"
491 help
492 Improves the CPU scheduler's decision making when dealing with
493 MultiThreading at a cost of slightly increased overhead in some
494 places. If unsure say N here.
495
496config NR_CPUS
497 int "Maximum number of CPUs (2-4096)"
498 range 2 4096
499 # These have to remain sorted largest to smallest
500 default "64"
501
502config HOTPLUG_CPU
503 bool "Support for hot-pluggable CPUs"
504 select GENERIC_IRQ_MIGRATION
505 help
506 Say Y here to experiment with turning CPUs off and on. CPUs
507 can be controlled through /sys/devices/system/cpu.
508
509source kernel/Kconfig.preempt
510source kernel/Kconfig.hz
511
512config ARCH_HAS_HOLES_MEMORYMODEL
513 def_bool y if SPARSEMEM
514
515config ARCH_SPARSEMEM_ENABLE
516 def_bool y
517 select SPARSEMEM_VMEMMAP_ENABLE
518
519config ARCH_SPARSEMEM_DEFAULT
520 def_bool ARCH_SPARSEMEM_ENABLE
521
522config ARCH_SELECT_MEMORY_MODEL
523 def_bool ARCH_SPARSEMEM_ENABLE
524
525config HAVE_ARCH_PFN_VALID
526 def_bool ARCH_HAS_HOLES_MEMORYMODEL || !SPARSEMEM
527
528config HW_PERF_EVENTS
529 def_bool y
530 depends on ARM_PMU
531
532config SYS_SUPPORTS_HUGETLBFS
533 def_bool y
534
535config ARCH_WANT_HUGE_PMD_SHARE
536 def_bool y if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
537
538config HAVE_ARCH_TRANSPARENT_HUGEPAGE
539 def_bool y
540
541config ARCH_HAS_CACHE_LINE_SIZE
542 def_bool y
543
544source "mm/Kconfig"
545
546config SECCOMP
547 bool "Enable seccomp to safely compute untrusted bytecode"
548 ---help---
549 This kernel feature is useful for number crunching applications
550 that may need to compute untrusted bytecode during their
551 execution. By using pipes or other transports made available to
552 the process as file descriptors supporting the read/write
553 syscalls, it's possible to isolate those applications in
554 their own address space using seccomp. Once seccomp is
555 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
556 and the task is only allowed to execute a few safe syscalls
557 defined by each seccomp mode.
558
559config PARAVIRT
560 bool "Enable paravirtualization code"
561 help
562 This changes the kernel so it can modify itself when it is run
563 under a hypervisor, potentially improving performance significantly
564 over full virtualization.
565
566config PARAVIRT_TIME_ACCOUNTING
567 bool "Paravirtual steal time accounting"
568 select PARAVIRT
569 default n
570 help
571 Select this option to enable fine granularity task steal time
572 accounting. Time spent executing other tasks in parallel with
573 the current vCPU is discounted from the vCPU power. To account for
574 that, there can be a small performance impact.
575
576 If in doubt, say N here.
577
578config XEN_DOM0
579 def_bool y
580 depends on XEN
581
582config XEN
583 bool "Xen guest support on ARM64"
584 depends on ARM64 && OF
585 select SWIOTLB_XEN
586 select PARAVIRT
587 help
588 Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64.
589
590config FORCE_MAX_ZONEORDER
591 int
592 default "14" if (ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE)
593 default "12" if (ARM64_16K_PAGES && TRANSPARENT_HUGEPAGE)
594 default "11"
595 help
596 The kernel memory allocator divides physically contiguous memory
597 blocks into "zones", where each zone is a power of two number of
598 pages. This option selects the largest power of two that the kernel
599 keeps in the memory allocator. If you need to allocate very large
600 blocks of physically contiguous memory, then you may need to
601 increase this value.
602
603 This config option is actually maximum order plus one. For example,
604 a value of 11 means that the largest free memory block is 2^10 pages.
605
606 We make sure that we can allocate upto a HugePage size for each configuration.
607 Hence we have :
608 MAX_ORDER = (PMD_SHIFT - PAGE_SHIFT) + 1 => PAGE_SHIFT - 2
609
610 However for 4K, we choose a higher default value, 11 as opposed to 10, giving us
611 4M allocations matching the default size used by generic code.
612
613menuconfig ARMV8_DEPRECATED
614 bool "Emulate deprecated/obsolete ARMv8 instructions"
615 depends on COMPAT
616 help
617 Legacy software support may require certain instructions
618 that have been deprecated or obsoleted in the architecture.
619
620 Enable this config to enable selective emulation of these
621 features.
622
623 If unsure, say Y
624
625if ARMV8_DEPRECATED
626
627config SWP_EMULATION
628 bool "Emulate SWP/SWPB instructions"
629 help
630 ARMv8 obsoletes the use of A32 SWP/SWPB instructions such that
631 they are always undefined. Say Y here to enable software
632 emulation of these instructions for userspace using LDXR/STXR.
633
634 In some older versions of glibc [<=2.8] SWP is used during futex
635 trylock() operations with the assumption that the code will not
636 be preempted. This invalid assumption may be more likely to fail
637 with SWP emulation enabled, leading to deadlock of the user
638 application.
639
640 NOTE: when accessing uncached shared regions, LDXR/STXR rely
641 on an external transaction monitoring block called a global
642 monitor to maintain update atomicity. If your system does not
643 implement a global monitor, this option can cause programs that
644 perform SWP operations to uncached memory to deadlock.
645
646 If unsure, say Y
647
648config CP15_BARRIER_EMULATION
649 bool "Emulate CP15 Barrier instructions"
650 help
651 The CP15 barrier instructions - CP15ISB, CP15DSB, and
652 CP15DMB - are deprecated in ARMv8 (and ARMv7). It is
653 strongly recommended to use the ISB, DSB, and DMB
654 instructions instead.
655
656 Say Y here to enable software emulation of these
657 instructions for AArch32 userspace code. When this option is
658 enabled, CP15 barrier usage is traced which can help
659 identify software that needs updating.
660
661 If unsure, say Y
662
663config SETEND_EMULATION
664 bool "Emulate SETEND instruction"
665 help
666 The SETEND instruction alters the data-endianness of the
667 AArch32 EL0, and is deprecated in ARMv8.
668
669 Say Y here to enable software emulation of the instruction
670 for AArch32 userspace code.
671
672 Note: All the cpus on the system must have mixed endian support at EL0
673 for this feature to be enabled. If a new CPU - which doesn't support mixed
674 endian - is hotplugged in after this feature has been enabled, there could
675 be unexpected results in the applications.
676
677 If unsure, say Y
678endif
679
680menu "ARMv8.1 architectural features"
681
682config ARM64_HW_AFDBM
683 bool "Support for hardware updates of the Access and Dirty page flags"
684 default y
685 help
686 The ARMv8.1 architecture extensions introduce support for
687 hardware updates of the access and dirty information in page
688 table entries. When enabled in TCR_EL1 (HA and HD bits) on
689 capable processors, accesses to pages with PTE_AF cleared will
690 set this bit instead of raising an access flag fault.
691 Similarly, writes to read-only pages with the DBM bit set will
692 clear the read-only bit (AP[2]) instead of raising a
693 permission fault.
694
695 Kernels built with this configuration option enabled continue
696 to work on pre-ARMv8.1 hardware and the performance impact is
697 minimal. If unsure, say Y.
698
699config ARM64_PAN
700 bool "Enable support for Privileged Access Never (PAN)"
701 default y
702 help
703 Privileged Access Never (PAN; part of the ARMv8.1 Extensions)
704 prevents the kernel or hypervisor from accessing user-space (EL0)
705 memory directly.
706
707 Choosing this option will cause any unprotected (not using
708 copy_to_user et al) memory access to fail with a permission fault.
709
710 The feature is detected at runtime, and will remain as a 'nop'
711 instruction if the cpu does not implement the feature.
712
713config ARM64_LSE_ATOMICS
714 bool "Atomic instructions"
715 help
716 As part of the Large System Extensions, ARMv8.1 introduces new
717 atomic instructions that are designed specifically to scale in
718 very large systems.
719
720 Say Y here to make use of these instructions for the in-kernel
721 atomic routines. This incurs a small overhead on CPUs that do
722 not support these instructions and requires the kernel to be
723 built with binutils >= 2.25.
724
725endmenu
726
727endmenu
728
729menu "Boot options"
730
731config CMDLINE
732 string "Default kernel command string"
733 default ""
734 help
735 Provide a set of default command-line options at build time by
736 entering them here. As a minimum, you should specify the the
737 root device (e.g. root=/dev/nfs).
738
739config CMDLINE_FORCE
740 bool "Always use the default kernel command string"
741 help
742 Always use the default kernel command string, even if the boot
743 loader passes other arguments to the kernel.
744 This is useful if you cannot or don't want to change the
745 command-line options your boot loader passes to the kernel.
746
747config EFI_STUB
748 bool
749
750config EFI
751 bool "UEFI runtime support"
752 depends on OF && !CPU_BIG_ENDIAN
753 select LIBFDT
754 select UCS2_STRING
755 select EFI_PARAMS_FROM_FDT
756 select EFI_RUNTIME_WRAPPERS
757 select EFI_STUB
758 select EFI_ARMSTUB
759 default y
760 help
761 This option provides support for runtime services provided
762 by UEFI firmware (such as non-volatile variables, realtime
763 clock, and platform reset). A UEFI stub is also provided to
764 allow the kernel to be booted as an EFI application. This
765 is only useful on systems that have UEFI firmware.
766
767config DMI
768 bool "Enable support for SMBIOS (DMI) tables"
769 depends on EFI
770 default y
771 help
772 This enables SMBIOS/DMI feature for systems.
773
774 This option is only useful on systems that have UEFI firmware.
775 However, even with this option, the resultant kernel should
776 continue to boot on existing non-UEFI platforms.
777
778endmenu
779
780menu "Userspace binary formats"
781
782source "fs/Kconfig.binfmt"
783
784config COMPAT
785 bool "Kernel support for 32-bit EL0"
786 depends on ARM64_4K_PAGES || EXPERT
787 select COMPAT_BINFMT_ELF
788 select HAVE_UID16
789 select OLD_SIGSUSPEND3
790 select COMPAT_OLD_SIGACTION
791 help
792 This option enables support for a 32-bit EL0 running under a 64-bit
793 kernel at EL1. AArch32-specific components such as system calls,
794 the user helper functions, VFP support and the ptrace interface are
795 handled appropriately by the kernel.
796
797 If you use a page size other than 4KB (i.e, 16KB or 64KB), please be aware
798 that you will only be able to execute AArch32 binaries that were compiled
799 with page size aligned segments.
800
801 If you want to execute 32-bit userspace applications, say Y.
802
803config SYSVIPC_COMPAT
804 def_bool y
805 depends on COMPAT && SYSVIPC
806
807endmenu
808
809menu "Power management options"
810
811source "kernel/power/Kconfig"
812
813config ARCH_SUSPEND_POSSIBLE
814 def_bool y
815
816endmenu
817
818menu "CPU Power Management"
819
820source "drivers/cpuidle/Kconfig"
821
822source "drivers/cpufreq/Kconfig"
823
824endmenu
825
826source "net/Kconfig"
827
828source "drivers/Kconfig"
829
830source "drivers/firmware/Kconfig"
831
832source "drivers/acpi/Kconfig"
833
834source "fs/Kconfig"
835
836source "arch/arm64/kvm/Kconfig"
837
838source "arch/arm64/Kconfig.debug"
839
840source "security/Kconfig"
841
842source "crypto/Kconfig"
843if CRYPTO
844source "arch/arm64/crypto/Kconfig"
845endif
846
847source "lib/Kconfig"