xref: /openbmc/linux/arch/arm64/Kconfig (revision 75305275)
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_ATOMIC64_DEC_IF_POSITIVE
7	select ARCH_HAS_ELF_RANDOMIZE
8	select ARCH_HAS_GCOV_PROFILE_ALL
9	select ARCH_HAS_SG_CHAIN
10	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
11	select ARCH_USE_CMPXCHG_LOCKREF
12	select ARCH_SUPPORTS_ATOMIC_RMW
13	select ARCH_WANT_OPTIONAL_GPIOLIB
14	select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
15	select ARCH_WANT_FRAME_POINTERS
16	select ARM_AMBA
17	select ARM_ARCH_TIMER
18	select ARM_GIC
19	select AUDIT_ARCH_COMPAT_GENERIC
20	select ARM_GIC_V2M if PCI_MSI
21	select ARM_GIC_V3
22	select ARM_GIC_V3_ITS if PCI_MSI
23	select ARM_PSCI_FW
24	select BUILDTIME_EXTABLE_SORT
25	select CLONE_BACKWARDS
26	select COMMON_CLK
27	select CPU_PM if (SUSPEND || CPU_IDLE)
28	select DCACHE_WORD_ACCESS
29	select EDAC_SUPPORT
30	select FRAME_POINTER
31	select GENERIC_ALLOCATOR
32	select GENERIC_CLOCKEVENTS
33	select GENERIC_CLOCKEVENTS_BROADCAST
34	select GENERIC_CPU_AUTOPROBE
35	select GENERIC_EARLY_IOREMAP
36	select GENERIC_IDLE_POLL_SETUP
37	select GENERIC_IRQ_PROBE
38	select GENERIC_IRQ_SHOW
39	select GENERIC_IRQ_SHOW_LEVEL
40	select GENERIC_PCI_IOMAP
41	select GENERIC_SCHED_CLOCK
42	select GENERIC_SMP_IDLE_THREAD
43	select GENERIC_STRNCPY_FROM_USER
44	select GENERIC_STRNLEN_USER
45	select GENERIC_TIME_VSYSCALL
46	select HANDLE_DOMAIN_IRQ
47	select HARDIRQS_SW_RESEND
48	select HAVE_ALIGNED_STRUCT_PAGE if SLUB
49	select HAVE_ARCH_AUDITSYSCALL
50	select HAVE_ARCH_BITREVERSE
51	select HAVE_ARCH_JUMP_LABEL
52	select HAVE_ARCH_KASAN if SPARSEMEM_VMEMMAP && !(ARM64_16K_PAGES && ARM64_VA_BITS_48)
53	select HAVE_ARCH_KGDB
54	select HAVE_ARCH_SECCOMP_FILTER
55	select HAVE_ARCH_TRACEHOOK
56	select HAVE_BPF_JIT
57	select HAVE_C_RECORDMCOUNT
58	select HAVE_CC_STACKPROTECTOR
59	select HAVE_CMPXCHG_DOUBLE
60	select HAVE_CMPXCHG_LOCAL
61	select HAVE_DEBUG_BUGVERBOSE
62	select HAVE_DEBUG_KMEMLEAK
63	select HAVE_DMA_API_DEBUG
64	select HAVE_DMA_ATTRS
65	select HAVE_DMA_CONTIGUOUS
66	select HAVE_DYNAMIC_FTRACE
67	select HAVE_EFFICIENT_UNALIGNED_ACCESS
68	select HAVE_FTRACE_MCOUNT_RECORD
69	select HAVE_FUNCTION_TRACER
70	select HAVE_FUNCTION_GRAPH_TRACER
71	select HAVE_GENERIC_DMA_COHERENT
72	select HAVE_HW_BREAKPOINT if PERF_EVENTS
73	select HAVE_MEMBLOCK
74	select HAVE_PATA_PLATFORM
75	select HAVE_PERF_EVENTS
76	select HAVE_PERF_REGS
77	select HAVE_PERF_USER_STACK_DUMP
78	select HAVE_RCU_TABLE_FREE
79	select HAVE_SYSCALL_TRACEPOINTS
80	select IOMMU_DMA if IOMMU_SUPPORT
81	select IRQ_DOMAIN
82	select IRQ_FORCED_THREADING
83	select MODULES_USE_ELF_RELA
84	select NO_BOOTMEM
85	select OF
86	select OF_EARLY_FLATTREE
87	select OF_RESERVED_MEM
88	select PERF_USE_VMALLOC
89	select POWER_RESET
90	select POWER_SUPPLY
91	select RTC_LIB
92	select SPARSE_IRQ
93	select SYSCTL_EXCEPTION_TRACE
94	select HAVE_CONTEXT_TRACKING
95	help
96	  ARM 64-bit (AArch64) Linux support.
97
98config 64BIT
99	def_bool y
100
101config ARCH_PHYS_ADDR_T_64BIT
102	def_bool y
103
104config MMU
105	def_bool y
106
107config NO_IOPORT_MAP
108	def_bool y if !PCI
109
110config STACKTRACE_SUPPORT
111	def_bool y
112
113config ILLEGAL_POINTER_VALUE
114	hex
115	default 0xdead000000000000
116
117config LOCKDEP_SUPPORT
118	def_bool y
119
120config TRACE_IRQFLAGS_SUPPORT
121	def_bool y
122
123config RWSEM_XCHGADD_ALGORITHM
124	def_bool y
125
126config GENERIC_BUG
127	def_bool y
128	depends on BUG
129
130config GENERIC_BUG_RELATIVE_POINTERS
131	def_bool y
132	depends on GENERIC_BUG
133
134config GENERIC_HWEIGHT
135	def_bool y
136
137config GENERIC_CSUM
138        def_bool y
139
140config GENERIC_CALIBRATE_DELAY
141	def_bool y
142
143config ZONE_DMA
144	def_bool y
145
146config HAVE_GENERIC_RCU_GUP
147	def_bool y
148
149config ARCH_DMA_ADDR_T_64BIT
150	def_bool y
151
152config NEED_DMA_MAP_STATE
153	def_bool y
154
155config NEED_SG_DMA_LENGTH
156	def_bool y
157
158config SMP
159	def_bool y
160
161config SWIOTLB
162	def_bool y
163
164config IOMMU_HELPER
165	def_bool SWIOTLB
166
167config KERNEL_MODE_NEON
168	def_bool y
169
170config FIX_EARLYCON_MEM
171	def_bool y
172
173config PGTABLE_LEVELS
174	int
175	default 2 if ARM64_16K_PAGES && ARM64_VA_BITS_36
176	default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42
177	default 3 if ARM64_64K_PAGES && ARM64_VA_BITS_48
178	default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39
179	default 3 if ARM64_16K_PAGES && ARM64_VA_BITS_47
180	default 4 if !ARM64_64K_PAGES && ARM64_VA_BITS_48
181
182source "init/Kconfig"
183
184source "kernel/Kconfig.freezer"
185
186source "arch/arm64/Kconfig.platforms"
187
188menu "Bus support"
189
190config PCI
191	bool "PCI support"
192	help
193	  This feature enables support for PCI bus system. If you say Y
194	  here, the kernel will include drivers and infrastructure code
195	  to support PCI bus devices.
196
197config PCI_DOMAINS
198	def_bool PCI
199
200config PCI_DOMAINS_GENERIC
201	def_bool PCI
202
203config PCI_SYSCALL
204	def_bool PCI
205
206source "drivers/pci/Kconfig"
207source "drivers/pci/pcie/Kconfig"
208source "drivers/pci/hotplug/Kconfig"
209
210endmenu
211
212menu "Kernel Features"
213
214menu "ARM errata workarounds via the alternatives framework"
215
216config ARM64_ERRATUM_826319
217	bool "Cortex-A53: 826319: System might deadlock if a write cannot complete until read data is accepted"
218	default y
219	help
220	  This option adds an alternative code sequence to work around ARM
221	  erratum 826319 on Cortex-A53 parts up to r0p2 with an AMBA 4 ACE or
222	  AXI master interface and an L2 cache.
223
224	  If a Cortex-A53 uses an AMBA AXI4 ACE interface to other processors
225	  and is unable to accept a certain write via this interface, it will
226	  not progress on read data presented on the read data channel and the
227	  system can deadlock.
228
229	  The workaround promotes data cache clean instructions to
230	  data cache clean-and-invalidate.
231	  Please note that this does not necessarily enable the workaround,
232	  as it depends on the alternative framework, which will only patch
233	  the kernel if an affected CPU is detected.
234
235	  If unsure, say Y.
236
237config ARM64_ERRATUM_827319
238	bool "Cortex-A53: 827319: Data cache clean instructions might cause overlapping transactions to the interconnect"
239	default y
240	help
241	  This option adds an alternative code sequence to work around ARM
242	  erratum 827319 on Cortex-A53 parts up to r0p2 with an AMBA 5 CHI
243	  master interface and an L2 cache.
244
245	  Under certain conditions this erratum can cause a clean line eviction
246	  to occur at the same time as another transaction to the same address
247	  on the AMBA 5 CHI interface, which can cause data corruption if the
248	  interconnect reorders the two transactions.
249
250	  The workaround promotes data cache clean instructions to
251	  data cache clean-and-invalidate.
252	  Please note that this does not necessarily enable the workaround,
253	  as it depends on the alternative framework, which will only patch
254	  the kernel if an affected CPU is detected.
255
256	  If unsure, say Y.
257
258config ARM64_ERRATUM_824069
259	bool "Cortex-A53: 824069: Cache line might not be marked as clean after a CleanShared snoop"
260	default y
261	help
262	  This option adds an alternative code sequence to work around ARM
263	  erratum 824069 on Cortex-A53 parts up to r0p2 when it is connected
264	  to a coherent interconnect.
265
266	  If a Cortex-A53 processor is executing a store or prefetch for
267	  write instruction at the same time as a processor in another
268	  cluster is executing a cache maintenance operation to the same
269	  address, then this erratum might cause a clean cache line to be
270	  incorrectly marked as dirty.
271
272	  The workaround promotes data cache clean instructions to
273	  data cache clean-and-invalidate.
274	  Please note that this option does not necessarily enable the
275	  workaround, as it depends on the alternative framework, which will
276	  only patch the kernel if an affected CPU is detected.
277
278	  If unsure, say Y.
279
280config ARM64_ERRATUM_819472
281	bool "Cortex-A53: 819472: Store exclusive instructions might cause data corruption"
282	default y
283	help
284	  This option adds an alternative code sequence to work around ARM
285	  erratum 819472 on Cortex-A53 parts up to r0p1 with an L2 cache
286	  present when it is connected to a coherent interconnect.
287
288	  If the processor is executing a load and store exclusive sequence at
289	  the same time as a processor in another cluster is executing a cache
290	  maintenance operation to the same address, then this erratum might
291	  cause data corruption.
292
293	  The workaround promotes data cache clean instructions to
294	  data cache clean-and-invalidate.
295	  Please note that this does not necessarily enable the workaround,
296	  as it depends on the alternative framework, which will only patch
297	  the kernel if an affected CPU is detected.
298
299	  If unsure, say Y.
300
301config ARM64_ERRATUM_832075
302	bool "Cortex-A57: 832075: possible deadlock on mixing exclusive memory accesses with device loads"
303	default y
304	help
305	  This option adds an alternative code sequence to work around ARM
306	  erratum 832075 on Cortex-A57 parts up to r1p2.
307
308	  Affected Cortex-A57 parts might deadlock when exclusive load/store
309	  instructions to Write-Back memory are mixed with Device loads.
310
311	  The workaround is to promote device loads to use Load-Acquire
312	  semantics.
313	  Please note that this does not necessarily enable the workaround,
314	  as it depends on the alternative framework, which will only patch
315	  the kernel if an affected CPU is detected.
316
317	  If unsure, say Y.
318
319config ARM64_ERRATUM_834220
320	bool "Cortex-A57: 834220: Stage 2 translation fault might be incorrectly reported in presence of a Stage 1 fault"
321	depends on KVM
322	default y
323	help
324	  This option adds an alternative code sequence to work around ARM
325	  erratum 834220 on Cortex-A57 parts up to r1p2.
326
327	  Affected Cortex-A57 parts might report a Stage 2 translation
328	  fault as the result of a Stage 1 fault for load crossing a
329	  page boundary when there is a permission or device memory
330	  alignment fault at Stage 1 and a translation fault at Stage 2.
331
332	  The workaround is to verify that the Stage 1 translation
333	  doesn't generate a fault before handling the Stage 2 fault.
334	  Please note that this does not necessarily enable the workaround,
335	  as it depends on the alternative framework, which will only patch
336	  the kernel if an affected CPU is detected.
337
338	  If unsure, say Y.
339
340config ARM64_ERRATUM_845719
341	bool "Cortex-A53: 845719: a load might read incorrect data"
342	depends on COMPAT
343	default y
344	help
345	  This option adds an alternative code sequence to work around ARM
346	  erratum 845719 on Cortex-A53 parts up to r0p4.
347
348	  When running a compat (AArch32) userspace on an affected Cortex-A53
349	  part, a load at EL0 from a virtual address that matches the bottom 32
350	  bits of the virtual address used by a recent load at (AArch64) EL1
351	  might return incorrect data.
352
353	  The workaround is to write the contextidr_el1 register on exception
354	  return to a 32-bit task.
355	  Please note that this does not necessarily enable the workaround,
356	  as it depends on the alternative framework, which will only patch
357	  the kernel if an affected CPU is detected.
358
359	  If unsure, say Y.
360
361config ARM64_ERRATUM_843419
362	bool "Cortex-A53: 843419: A load or store might access an incorrect address"
363	depends on MODULES
364	default y
365	help
366	  This option builds kernel modules using the large memory model in
367	  order to avoid the use of the ADRP instruction, which can cause
368	  a subsequent memory access to use an incorrect address on Cortex-A53
369	  parts up to r0p4.
370
371	  Note that the kernel itself must be linked with a version of ld
372	  which fixes potentially affected ADRP instructions through the
373	  use of veneers.
374
375	  If unsure, say Y.
376
377config CAVIUM_ERRATUM_22375
378	bool "Cavium erratum 22375, 24313"
379	default y
380	help
381	  Enable workaround for erratum 22375, 24313.
382
383	  This implements two gicv3-its errata workarounds for ThunderX. Both
384	  with small impact affecting only ITS table allocation.
385
386	    erratum 22375: only alloc 8MB table size
387	    erratum 24313: ignore memory access type
388
389	  The fixes are in ITS initialization and basically ignore memory access
390	  type and table size provided by the TYPER and BASER registers.
391
392	  If unsure, say Y.
393
394config CAVIUM_ERRATUM_23154
395	bool "Cavium erratum 23154: Access to ICC_IAR1_EL1 is not sync'ed"
396	default y
397	help
398	  The gicv3 of ThunderX requires a modified version for
399	  reading the IAR status to ensure data synchronization
400	  (access to icc_iar1_el1 is not sync'ed before and after).
401
402	  If unsure, say Y.
403
404endmenu
405
406
407choice
408	prompt "Page size"
409	default ARM64_4K_PAGES
410	help
411	  Page size (translation granule) configuration.
412
413config ARM64_4K_PAGES
414	bool "4KB"
415	help
416	  This feature enables 4KB pages support.
417
418config ARM64_16K_PAGES
419	bool "16KB"
420	help
421	  The system will use 16KB pages support. AArch32 emulation
422	  requires applications compiled with 16K (or a multiple of 16K)
423	  aligned segments.
424
425config ARM64_64K_PAGES
426	bool "64KB"
427	help
428	  This feature enables 64KB pages support (4KB by default)
429	  allowing only two levels of page tables and faster TLB
430	  look-up. AArch32 emulation requires applications compiled
431	  with 64K aligned segments.
432
433endchoice
434
435choice
436	prompt "Virtual address space size"
437	default ARM64_VA_BITS_39 if ARM64_4K_PAGES
438	default ARM64_VA_BITS_47 if ARM64_16K_PAGES
439	default ARM64_VA_BITS_42 if ARM64_64K_PAGES
440	help
441	  Allows choosing one of multiple possible virtual address
442	  space sizes. The level of translation table is determined by
443	  a combination of page size and virtual address space size.
444
445config ARM64_VA_BITS_36
446	bool "36-bit" if EXPERT
447	depends on ARM64_16K_PAGES
448
449config ARM64_VA_BITS_39
450	bool "39-bit"
451	depends on ARM64_4K_PAGES
452
453config ARM64_VA_BITS_42
454	bool "42-bit"
455	depends on ARM64_64K_PAGES
456
457config ARM64_VA_BITS_47
458	bool "47-bit"
459	depends on ARM64_16K_PAGES
460
461config ARM64_VA_BITS_48
462	bool "48-bit"
463
464endchoice
465
466config ARM64_VA_BITS
467	int
468	default 36 if ARM64_VA_BITS_36
469	default 39 if ARM64_VA_BITS_39
470	default 42 if ARM64_VA_BITS_42
471	default 47 if ARM64_VA_BITS_47
472	default 48 if ARM64_VA_BITS_48
473
474config CPU_BIG_ENDIAN
475       bool "Build big-endian kernel"
476       help
477         Say Y if you plan on running a kernel in big-endian mode.
478
479config SCHED_MC
480	bool "Multi-core scheduler support"
481	help
482	  Multi-core scheduler support improves the CPU scheduler's decision
483	  making when dealing with multi-core CPU chips at a cost of slightly
484	  increased overhead in some places. If unsure say N here.
485
486config SCHED_SMT
487	bool "SMT scheduler support"
488	help
489	  Improves the CPU scheduler's decision making when dealing with
490	  MultiThreading at a cost of slightly increased overhead in some
491	  places. If unsure say N here.
492
493config NR_CPUS
494	int "Maximum number of CPUs (2-4096)"
495	range 2 4096
496	# These have to remain sorted largest to smallest
497	default "64"
498
499config HOTPLUG_CPU
500	bool "Support for hot-pluggable CPUs"
501	select GENERIC_IRQ_MIGRATION
502	help
503	  Say Y here to experiment with turning CPUs off and on.  CPUs
504	  can be controlled through /sys/devices/system/cpu.
505
506source kernel/Kconfig.preempt
507source kernel/Kconfig.hz
508
509config ARCH_HAS_HOLES_MEMORYMODEL
510	def_bool y if SPARSEMEM
511
512config ARCH_SPARSEMEM_ENABLE
513	def_bool y
514	select SPARSEMEM_VMEMMAP_ENABLE
515
516config ARCH_SPARSEMEM_DEFAULT
517	def_bool ARCH_SPARSEMEM_ENABLE
518
519config ARCH_SELECT_MEMORY_MODEL
520	def_bool ARCH_SPARSEMEM_ENABLE
521
522config HAVE_ARCH_PFN_VALID
523	def_bool ARCH_HAS_HOLES_MEMORYMODEL || !SPARSEMEM
524
525config HW_PERF_EVENTS
526	def_bool y
527	depends on ARM_PMU
528
529config SYS_SUPPORTS_HUGETLBFS
530	def_bool y
531
532config ARCH_WANT_GENERAL_HUGETLB
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 XEN_DOM0
560	def_bool y
561	depends on XEN
562
563config XEN
564	bool "Xen guest support on ARM64"
565	depends on ARM64 && OF
566	select SWIOTLB_XEN
567	help
568	  Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64.
569
570config FORCE_MAX_ZONEORDER
571	int
572	default "14" if (ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE)
573	default "12" if (ARM64_16K_PAGES && TRANSPARENT_HUGEPAGE)
574	default "11"
575	help
576	  The kernel memory allocator divides physically contiguous memory
577	  blocks into "zones", where each zone is a power of two number of
578	  pages.  This option selects the largest power of two that the kernel
579	  keeps in the memory allocator.  If you need to allocate very large
580	  blocks of physically contiguous memory, then you may need to
581	  increase this value.
582
583	  This config option is actually maximum order plus one. For example,
584	  a value of 11 means that the largest free memory block is 2^10 pages.
585
586	  We make sure that we can allocate upto a HugePage size for each configuration.
587	  Hence we have :
588		MAX_ORDER = (PMD_SHIFT - PAGE_SHIFT) + 1 => PAGE_SHIFT - 2
589
590	  However for 4K, we choose a higher default value, 11 as opposed to 10, giving us
591	  4M allocations matching the default size used by generic code.
592
593menuconfig ARMV8_DEPRECATED
594	bool "Emulate deprecated/obsolete ARMv8 instructions"
595	depends on COMPAT
596	help
597	  Legacy software support may require certain instructions
598	  that have been deprecated or obsoleted in the architecture.
599
600	  Enable this config to enable selective emulation of these
601	  features.
602
603	  If unsure, say Y
604
605if ARMV8_DEPRECATED
606
607config SWP_EMULATION
608	bool "Emulate SWP/SWPB instructions"
609	help
610	  ARMv8 obsoletes the use of A32 SWP/SWPB instructions such that
611	  they are always undefined. Say Y here to enable software
612	  emulation of these instructions for userspace using LDXR/STXR.
613
614	  In some older versions of glibc [<=2.8] SWP is used during futex
615	  trylock() operations with the assumption that the code will not
616	  be preempted. This invalid assumption may be more likely to fail
617	  with SWP emulation enabled, leading to deadlock of the user
618	  application.
619
620	  NOTE: when accessing uncached shared regions, LDXR/STXR rely
621	  on an external transaction monitoring block called a global
622	  monitor to maintain update atomicity. If your system does not
623	  implement a global monitor, this option can cause programs that
624	  perform SWP operations to uncached memory to deadlock.
625
626	  If unsure, say Y
627
628config CP15_BARRIER_EMULATION
629	bool "Emulate CP15 Barrier instructions"
630	help
631	  The CP15 barrier instructions - CP15ISB, CP15DSB, and
632	  CP15DMB - are deprecated in ARMv8 (and ARMv7). It is
633	  strongly recommended to use the ISB, DSB, and DMB
634	  instructions instead.
635
636	  Say Y here to enable software emulation of these
637	  instructions for AArch32 userspace code. When this option is
638	  enabled, CP15 barrier usage is traced which can help
639	  identify software that needs updating.
640
641	  If unsure, say Y
642
643config SETEND_EMULATION
644	bool "Emulate SETEND instruction"
645	help
646	  The SETEND instruction alters the data-endianness of the
647	  AArch32 EL0, and is deprecated in ARMv8.
648
649	  Say Y here to enable software emulation of the instruction
650	  for AArch32 userspace code.
651
652	  Note: All the cpus on the system must have mixed endian support at EL0
653	  for this feature to be enabled. If a new CPU - which doesn't support mixed
654	  endian - is hotplugged in after this feature has been enabled, there could
655	  be unexpected results in the applications.
656
657	  If unsure, say Y
658endif
659
660menu "ARMv8.1 architectural features"
661
662config ARM64_HW_AFDBM
663	bool "Support for hardware updates of the Access and Dirty page flags"
664	default y
665	help
666	  The ARMv8.1 architecture extensions introduce support for
667	  hardware updates of the access and dirty information in page
668	  table entries. When enabled in TCR_EL1 (HA and HD bits) on
669	  capable processors, accesses to pages with PTE_AF cleared will
670	  set this bit instead of raising an access flag fault.
671	  Similarly, writes to read-only pages with the DBM bit set will
672	  clear the read-only bit (AP[2]) instead of raising a
673	  permission fault.
674
675	  Kernels built with this configuration option enabled continue
676	  to work on pre-ARMv8.1 hardware and the performance impact is
677	  minimal. If unsure, say Y.
678
679config ARM64_PAN
680	bool "Enable support for Privileged Access Never (PAN)"
681	default y
682	help
683	 Privileged Access Never (PAN; part of the ARMv8.1 Extensions)
684	 prevents the kernel or hypervisor from accessing user-space (EL0)
685	 memory directly.
686
687	 Choosing this option will cause any unprotected (not using
688	 copy_to_user et al) memory access to fail with a permission fault.
689
690	 The feature is detected at runtime, and will remain as a 'nop'
691	 instruction if the cpu does not implement the feature.
692
693config ARM64_LSE_ATOMICS
694	bool "Atomic instructions"
695	help
696	  As part of the Large System Extensions, ARMv8.1 introduces new
697	  atomic instructions that are designed specifically to scale in
698	  very large systems.
699
700	  Say Y here to make use of these instructions for the in-kernel
701	  atomic routines. This incurs a small overhead on CPUs that do
702	  not support these instructions and requires the kernel to be
703	  built with binutils >= 2.25.
704
705endmenu
706
707endmenu
708
709menu "Boot options"
710
711config CMDLINE
712	string "Default kernel command string"
713	default ""
714	help
715	  Provide a set of default command-line options at build time by
716	  entering them here. As a minimum, you should specify the the
717	  root device (e.g. root=/dev/nfs).
718
719config CMDLINE_FORCE
720	bool "Always use the default kernel command string"
721	help
722	  Always use the default kernel command string, even if the boot
723	  loader passes other arguments to the kernel.
724	  This is useful if you cannot or don't want to change the
725	  command-line options your boot loader passes to the kernel.
726
727config EFI_STUB
728	bool
729
730config EFI
731	bool "UEFI runtime support"
732	depends on OF && !CPU_BIG_ENDIAN
733	select LIBFDT
734	select UCS2_STRING
735	select EFI_PARAMS_FROM_FDT
736	select EFI_RUNTIME_WRAPPERS
737	select EFI_STUB
738	select EFI_ARMSTUB
739	default y
740	help
741	  This option provides support for runtime services provided
742	  by UEFI firmware (such as non-volatile variables, realtime
743          clock, and platform reset). A UEFI stub is also provided to
744	  allow the kernel to be booted as an EFI application. This
745	  is only useful on systems that have UEFI firmware.
746
747config DMI
748	bool "Enable support for SMBIOS (DMI) tables"
749	depends on EFI
750	default y
751	help
752	  This enables SMBIOS/DMI feature for systems.
753
754	  This option is only useful on systems that have UEFI firmware.
755	  However, even with this option, the resultant kernel should
756	  continue to boot on existing non-UEFI platforms.
757
758endmenu
759
760menu "Userspace binary formats"
761
762source "fs/Kconfig.binfmt"
763
764config COMPAT
765	bool "Kernel support for 32-bit EL0"
766	depends on ARM64_4K_PAGES || EXPERT
767	select COMPAT_BINFMT_ELF
768	select HAVE_UID16
769	select OLD_SIGSUSPEND3
770	select COMPAT_OLD_SIGACTION
771	help
772	  This option enables support for a 32-bit EL0 running under a 64-bit
773	  kernel at EL1. AArch32-specific components such as system calls,
774	  the user helper functions, VFP support and the ptrace interface are
775	  handled appropriately by the kernel.
776
777	  If you use a page size other than 4KB (i.e, 16KB or 64KB), please be aware
778	  that you will only be able to execute AArch32 binaries that were compiled
779	  with page size aligned segments.
780
781	  If you want to execute 32-bit userspace applications, say Y.
782
783config SYSVIPC_COMPAT
784	def_bool y
785	depends on COMPAT && SYSVIPC
786
787endmenu
788
789menu "Power management options"
790
791source "kernel/power/Kconfig"
792
793config ARCH_SUSPEND_POSSIBLE
794	def_bool y
795
796endmenu
797
798menu "CPU Power Management"
799
800source "drivers/cpuidle/Kconfig"
801
802source "drivers/cpufreq/Kconfig"
803
804endmenu
805
806source "net/Kconfig"
807
808source "drivers/Kconfig"
809
810source "drivers/firmware/Kconfig"
811
812source "drivers/acpi/Kconfig"
813
814source "fs/Kconfig"
815
816source "arch/arm64/kvm/Kconfig"
817
818source "arch/arm64/Kconfig.debug"
819
820source "security/Kconfig"
821
822source "crypto/Kconfig"
823if CRYPTO
824source "arch/arm64/crypto/Kconfig"
825endif
826
827source "lib/Kconfig"
828