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[mirror_ubuntu-focal-kernel.git] / arch / arm64 / Kconfig
1 config ARM64
2 def_bool y
3 select ACPI_CCA_REQUIRED if ACPI
4 select ACPI_GENERIC_GSI if ACPI
5 select ACPI_GTDT if ACPI
6 select ACPI_IORT if ACPI
7 select ACPI_REDUCED_HARDWARE_ONLY if ACPI
8 select ACPI_MCFG if (ACPI && PCI)
9 select ACPI_SPCR_TABLE if ACPI
10 select ACPI_PPTT if ACPI
11 select ARCH_CLOCKSOURCE_DATA
12 select ARCH_HAS_DEBUG_VIRTUAL
13 select ARCH_HAS_DEVMEM_IS_ALLOWED
14 select ARCH_HAS_DMA_COHERENT_TO_PFN
15 select ARCH_HAS_DMA_MMAP_PGPROT
16 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
17 select ARCH_HAS_ELF_RANDOMIZE
18 select ARCH_HAS_FAST_MULTIPLIER
19 select ARCH_HAS_FORTIFY_SOURCE
20 select ARCH_HAS_GCOV_PROFILE_ALL
21 select ARCH_HAS_GIGANTIC_PAGE if (MEMORY_ISOLATION && COMPACTION) || CMA
22 select ARCH_HAS_KCOV
23 select ARCH_HAS_MEMBARRIER_SYNC_CORE
24 select ARCH_HAS_PTE_SPECIAL
25 select ARCH_HAS_SET_MEMORY
26 select ARCH_HAS_STRICT_KERNEL_RWX
27 select ARCH_HAS_STRICT_MODULE_RWX
28 select ARCH_HAS_SYNC_DMA_FOR_DEVICE
29 select ARCH_HAS_SYNC_DMA_FOR_CPU
30 select ARCH_HAS_SYSCALL_WRAPPER
31 select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
32 select ARCH_HAVE_NMI_SAFE_CMPXCHG
33 select ARCH_INLINE_READ_LOCK if !PREEMPT
34 select ARCH_INLINE_READ_LOCK_BH if !PREEMPT
35 select ARCH_INLINE_READ_LOCK_IRQ if !PREEMPT
36 select ARCH_INLINE_READ_LOCK_IRQSAVE if !PREEMPT
37 select ARCH_INLINE_READ_UNLOCK if !PREEMPT
38 select ARCH_INLINE_READ_UNLOCK_BH if !PREEMPT
39 select ARCH_INLINE_READ_UNLOCK_IRQ if !PREEMPT
40 select ARCH_INLINE_READ_UNLOCK_IRQRESTORE if !PREEMPT
41 select ARCH_INLINE_WRITE_LOCK if !PREEMPT
42 select ARCH_INLINE_WRITE_LOCK_BH if !PREEMPT
43 select ARCH_INLINE_WRITE_LOCK_IRQ if !PREEMPT
44 select ARCH_INLINE_WRITE_LOCK_IRQSAVE if !PREEMPT
45 select ARCH_INLINE_WRITE_UNLOCK if !PREEMPT
46 select ARCH_INLINE_WRITE_UNLOCK_BH if !PREEMPT
47 select ARCH_INLINE_WRITE_UNLOCK_IRQ if !PREEMPT
48 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE if !PREEMPT
49 select ARCH_INLINE_SPIN_TRYLOCK if !PREEMPT
50 select ARCH_INLINE_SPIN_TRYLOCK_BH if !PREEMPT
51 select ARCH_INLINE_SPIN_LOCK if !PREEMPT
52 select ARCH_INLINE_SPIN_LOCK_BH if !PREEMPT
53 select ARCH_INLINE_SPIN_LOCK_IRQ if !PREEMPT
54 select ARCH_INLINE_SPIN_LOCK_IRQSAVE if !PREEMPT
55 select ARCH_INLINE_SPIN_UNLOCK if !PREEMPT
56 select ARCH_INLINE_SPIN_UNLOCK_BH if !PREEMPT
57 select ARCH_INLINE_SPIN_UNLOCK_IRQ if !PREEMPT
58 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPT
59 select ARCH_USE_CMPXCHG_LOCKREF
60 select ARCH_USE_QUEUED_RWLOCKS
61 select ARCH_USE_QUEUED_SPINLOCKS
62 select ARCH_SUPPORTS_MEMORY_FAILURE
63 select ARCH_SUPPORTS_ATOMIC_RMW
64 select ARCH_SUPPORTS_INT128 if GCC_VERSION >= 50000 || CC_IS_CLANG
65 select ARCH_SUPPORTS_NUMA_BALANCING
66 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
67 select ARCH_WANT_FRAME_POINTERS
68 select ARCH_HAS_UBSAN_SANITIZE_ALL
69 select ARM_AMBA
70 select ARM_ARCH_TIMER
71 select ARM_GIC
72 select AUDIT_ARCH_COMPAT_GENERIC
73 select ARM_GIC_V2M if PCI
74 select ARM_GIC_V3
75 select ARM_GIC_V3_ITS if PCI
76 select ARM_PSCI_FW
77 select BUILDTIME_EXTABLE_SORT
78 select CLONE_BACKWARDS
79 select COMMON_CLK
80 select CPU_PM if (SUSPEND || CPU_IDLE)
81 select CRC32
82 select DCACHE_WORD_ACCESS
83 select DMA_DIRECT_REMAP
84 select EDAC_SUPPORT
85 select FRAME_POINTER
86 select GENERIC_ALLOCATOR
87 select GENERIC_ARCH_TOPOLOGY
88 select GENERIC_CLOCKEVENTS
89 select GENERIC_CLOCKEVENTS_BROADCAST
90 select GENERIC_CPU_AUTOPROBE
91 select GENERIC_EARLY_IOREMAP
92 select GENERIC_IDLE_POLL_SETUP
93 select GENERIC_IRQ_MULTI_HANDLER
94 select GENERIC_IRQ_PROBE
95 select GENERIC_IRQ_SHOW
96 select GENERIC_IRQ_SHOW_LEVEL
97 select GENERIC_PCI_IOMAP
98 select GENERIC_SCHED_CLOCK
99 select GENERIC_SMP_IDLE_THREAD
100 select GENERIC_STRNCPY_FROM_USER
101 select GENERIC_STRNLEN_USER
102 select GENERIC_TIME_VSYSCALL
103 select HANDLE_DOMAIN_IRQ
104 select HARDIRQS_SW_RESEND
105 select HAVE_ACPI_APEI if (ACPI && EFI)
106 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
107 select HAVE_ARCH_AUDITSYSCALL
108 select HAVE_ARCH_BITREVERSE
109 select HAVE_ARCH_HUGE_VMAP
110 select HAVE_ARCH_JUMP_LABEL
111 select HAVE_ARCH_JUMP_LABEL_RELATIVE
112 select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48)
113 select HAVE_ARCH_KGDB
114 select HAVE_ARCH_MMAP_RND_BITS
115 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
116 select HAVE_ARCH_PREL32_RELOCATIONS
117 select HAVE_ARCH_SECCOMP_FILTER
118 select HAVE_ARCH_STACKLEAK
119 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
120 select HAVE_ARCH_TRACEHOOK
121 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
122 select HAVE_ARCH_VMAP_STACK
123 select HAVE_ARM_SMCCC
124 select HAVE_EBPF_JIT
125 select HAVE_C_RECORDMCOUNT
126 select HAVE_CMPXCHG_DOUBLE
127 select HAVE_CMPXCHG_LOCAL
128 select HAVE_CONTEXT_TRACKING
129 select HAVE_DEBUG_BUGVERBOSE
130 select HAVE_DEBUG_KMEMLEAK
131 select HAVE_DMA_CONTIGUOUS
132 select HAVE_DYNAMIC_FTRACE
133 select HAVE_EFFICIENT_UNALIGNED_ACCESS
134 select HAVE_FTRACE_MCOUNT_RECORD
135 select HAVE_FUNCTION_TRACER
136 select HAVE_FUNCTION_GRAPH_TRACER
137 select HAVE_GCC_PLUGINS
138 select HAVE_GENERIC_DMA_COHERENT
139 select HAVE_HW_BREAKPOINT if PERF_EVENTS
140 select HAVE_IRQ_TIME_ACCOUNTING
141 select HAVE_MEMBLOCK_NODE_MAP if NUMA
142 select HAVE_NMI
143 select HAVE_PATA_PLATFORM
144 select HAVE_PERF_EVENTS
145 select HAVE_PERF_REGS
146 select HAVE_PERF_USER_STACK_DUMP
147 select HAVE_REGS_AND_STACK_ACCESS_API
148 select HAVE_RCU_TABLE_FREE
149 select HAVE_RCU_TABLE_INVALIDATE
150 select HAVE_RSEQ
151 select HAVE_STACKPROTECTOR
152 select HAVE_SYSCALL_TRACEPOINTS
153 select HAVE_KPROBES
154 select HAVE_KRETPROBES
155 select IOMMU_DMA if IOMMU_SUPPORT
156 select IRQ_DOMAIN
157 select IRQ_FORCED_THREADING
158 select MODULES_USE_ELF_RELA
159 select MULTI_IRQ_HANDLER
160 select NEED_DMA_MAP_STATE
161 select NEED_SG_DMA_LENGTH
162 select OF
163 select OF_EARLY_FLATTREE
164 select OF_RESERVED_MEM
165 select PCI_ECAM if (ACPI && PCI)
166 select POWER_RESET
167 select POWER_SUPPLY
168 select REFCOUNT_FULL
169 select SPARSE_IRQ
170 select SWIOTLB
171 select SYSCTL_EXCEPTION_TRACE
172 select THREAD_INFO_IN_TASK
173 help
174 ARM 64-bit (AArch64) Linux support.
175
176 config 64BIT
177 def_bool y
178
179 config MMU
180 def_bool y
181
182 config ARM64_PAGE_SHIFT
183 int
184 default 16 if ARM64_64K_PAGES
185 default 14 if ARM64_16K_PAGES
186 default 12
187
188 config ARM64_CONT_SHIFT
189 int
190 default 5 if ARM64_64K_PAGES
191 default 7 if ARM64_16K_PAGES
192 default 4
193
194 config ARCH_MMAP_RND_BITS_MIN
195 default 14 if ARM64_64K_PAGES
196 default 16 if ARM64_16K_PAGES
197 default 18
198
199 # max bits determined by the following formula:
200 # VA_BITS - PAGE_SHIFT - 3
201 config ARCH_MMAP_RND_BITS_MAX
202 default 19 if ARM64_VA_BITS=36
203 default 24 if ARM64_VA_BITS=39
204 default 27 if ARM64_VA_BITS=42
205 default 30 if ARM64_VA_BITS=47
206 default 29 if ARM64_VA_BITS=48 && ARM64_64K_PAGES
207 default 31 if ARM64_VA_BITS=48 && ARM64_16K_PAGES
208 default 33 if ARM64_VA_BITS=48
209 default 14 if ARM64_64K_PAGES
210 default 16 if ARM64_16K_PAGES
211 default 18
212
213 config ARCH_MMAP_RND_COMPAT_BITS_MIN
214 default 7 if ARM64_64K_PAGES
215 default 9 if ARM64_16K_PAGES
216 default 11
217
218 config ARCH_MMAP_RND_COMPAT_BITS_MAX
219 default 16
220
221 config NO_IOPORT_MAP
222 def_bool y if !PCI
223
224 config STACKTRACE_SUPPORT
225 def_bool y
226
227 config ILLEGAL_POINTER_VALUE
228 hex
229 default 0xdead000000000000
230
231 config LOCKDEP_SUPPORT
232 def_bool y
233
234 config TRACE_IRQFLAGS_SUPPORT
235 def_bool y
236
237 config RWSEM_XCHGADD_ALGORITHM
238 def_bool y
239
240 config GENERIC_BUG
241 def_bool y
242 depends on BUG
243
244 config GENERIC_BUG_RELATIVE_POINTERS
245 def_bool y
246 depends on GENERIC_BUG
247
248 config GENERIC_HWEIGHT
249 def_bool y
250
251 config GENERIC_CSUM
252 def_bool y
253
254 config GENERIC_CALIBRATE_DELAY
255 def_bool y
256
257 config ZONE_DMA32
258 def_bool y
259
260 config HAVE_GENERIC_GUP
261 def_bool y
262
263 config ARCH_ENABLE_MEMORY_HOTPLUG
264 def_bool y
265
266 config SMP
267 def_bool y
268
269 config KERNEL_MODE_NEON
270 def_bool y
271
272 config FIX_EARLYCON_MEM
273 def_bool y
274
275 config PGTABLE_LEVELS
276 int
277 default 2 if ARM64_16K_PAGES && ARM64_VA_BITS_36
278 default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42
279 default 3 if ARM64_64K_PAGES && (ARM64_VA_BITS_48 || ARM64_USER_VA_BITS_52)
280 default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39
281 default 3 if ARM64_16K_PAGES && ARM64_VA_BITS_47
282 default 4 if !ARM64_64K_PAGES && ARM64_VA_BITS_48
283
284 config ARCH_SUPPORTS_UPROBES
285 def_bool y
286
287 config ARCH_PROC_KCORE_TEXT
288 def_bool y
289
290 source "arch/arm64/Kconfig.platforms"
291
292 menu "Bus support"
293
294 config PCI
295 bool "PCI support"
296 help
297 This feature enables support for PCI bus system. If you say Y
298 here, the kernel will include drivers and infrastructure code
299 to support PCI bus devices.
300
301 config PCI_DOMAINS
302 def_bool PCI
303
304 config PCI_DOMAINS_GENERIC
305 def_bool PCI
306
307 config PCI_SYSCALL
308 def_bool PCI
309
310 source "drivers/pci/Kconfig"
311
312 endmenu
313
314 menu "Kernel Features"
315
316 menu "ARM errata workarounds via the alternatives framework"
317
318 config ARM64_WORKAROUND_CLEAN_CACHE
319 def_bool n
320
321 config ARM64_ERRATUM_826319
322 bool "Cortex-A53: 826319: System might deadlock if a write cannot complete until read data is accepted"
323 default y
324 select ARM64_WORKAROUND_CLEAN_CACHE
325 help
326 This option adds an alternative code sequence to work around ARM
327 erratum 826319 on Cortex-A53 parts up to r0p2 with an AMBA 4 ACE or
328 AXI master interface and an L2 cache.
329
330 If a Cortex-A53 uses an AMBA AXI4 ACE interface to other processors
331 and is unable to accept a certain write via this interface, it will
332 not progress on read data presented on the read data channel and the
333 system can deadlock.
334
335 The workaround promotes data cache clean instructions to
336 data cache clean-and-invalidate.
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
343 config ARM64_ERRATUM_827319
344 bool "Cortex-A53: 827319: Data cache clean instructions might cause overlapping transactions to the interconnect"
345 default y
346 select ARM64_WORKAROUND_CLEAN_CACHE
347 help
348 This option adds an alternative code sequence to work around ARM
349 erratum 827319 on Cortex-A53 parts up to r0p2 with an AMBA 5 CHI
350 master interface and an L2 cache.
351
352 Under certain conditions this erratum can cause a clean line eviction
353 to occur at the same time as another transaction to the same address
354 on the AMBA 5 CHI interface, which can cause data corruption if the
355 interconnect reorders the two transactions.
356
357 The workaround promotes data cache clean instructions to
358 data cache clean-and-invalidate.
359 Please note that this does not necessarily enable the workaround,
360 as it depends on the alternative framework, which will only patch
361 the kernel if an affected CPU is detected.
362
363 If unsure, say Y.
364
365 config ARM64_ERRATUM_824069
366 bool "Cortex-A53: 824069: Cache line might not be marked as clean after a CleanShared snoop"
367 default y
368 select ARM64_WORKAROUND_CLEAN_CACHE
369 help
370 This option adds an alternative code sequence to work around ARM
371 erratum 824069 on Cortex-A53 parts up to r0p2 when it is connected
372 to a coherent interconnect.
373
374 If a Cortex-A53 processor is executing a store or prefetch for
375 write instruction at the same time as a processor in another
376 cluster is executing a cache maintenance operation to the same
377 address, then this erratum might cause a clean cache line to be
378 incorrectly marked as dirty.
379
380 The workaround promotes data cache clean instructions to
381 data cache clean-and-invalidate.
382 Please note that this option does not necessarily enable the
383 workaround, as it depends on the alternative framework, which will
384 only patch the kernel if an affected CPU is detected.
385
386 If unsure, say Y.
387
388 config ARM64_ERRATUM_819472
389 bool "Cortex-A53: 819472: Store exclusive instructions might cause data corruption"
390 default y
391 select ARM64_WORKAROUND_CLEAN_CACHE
392 help
393 This option adds an alternative code sequence to work around ARM
394 erratum 819472 on Cortex-A53 parts up to r0p1 with an L2 cache
395 present when it is connected to a coherent interconnect.
396
397 If the processor is executing a load and store exclusive sequence at
398 the same time as a processor in another cluster is executing a cache
399 maintenance operation to the same address, then this erratum might
400 cause data corruption.
401
402 The workaround promotes data cache clean instructions to
403 data cache clean-and-invalidate.
404 Please note that this does not necessarily enable the workaround,
405 as it depends on the alternative framework, which will only patch
406 the kernel if an affected CPU is detected.
407
408 If unsure, say Y.
409
410 config ARM64_ERRATUM_832075
411 bool "Cortex-A57: 832075: possible deadlock on mixing exclusive memory accesses with device loads"
412 default y
413 help
414 This option adds an alternative code sequence to work around ARM
415 erratum 832075 on Cortex-A57 parts up to r1p2.
416
417 Affected Cortex-A57 parts might deadlock when exclusive load/store
418 instructions to Write-Back memory are mixed with Device loads.
419
420 The workaround is to promote device loads to use Load-Acquire
421 semantics.
422 Please note that this does not necessarily enable the workaround,
423 as it depends on the alternative framework, which will only patch
424 the kernel if an affected CPU is detected.
425
426 If unsure, say Y.
427
428 config ARM64_ERRATUM_834220
429 bool "Cortex-A57: 834220: Stage 2 translation fault might be incorrectly reported in presence of a Stage 1 fault"
430 depends on KVM
431 default y
432 help
433 This option adds an alternative code sequence to work around ARM
434 erratum 834220 on Cortex-A57 parts up to r1p2.
435
436 Affected Cortex-A57 parts might report a Stage 2 translation
437 fault as the result of a Stage 1 fault for load crossing a
438 page boundary when there is a permission or device memory
439 alignment fault at Stage 1 and a translation fault at Stage 2.
440
441 The workaround is to verify that the Stage 1 translation
442 doesn't generate a fault before handling the Stage 2 fault.
443 Please note that this does not necessarily enable the workaround,
444 as it depends on the alternative framework, which will only patch
445 the kernel if an affected CPU is detected.
446
447 If unsure, say Y.
448
449 config ARM64_ERRATUM_845719
450 bool "Cortex-A53: 845719: a load might read incorrect data"
451 depends on COMPAT
452 default y
453 help
454 This option adds an alternative code sequence to work around ARM
455 erratum 845719 on Cortex-A53 parts up to r0p4.
456
457 When running a compat (AArch32) userspace on an affected Cortex-A53
458 part, a load at EL0 from a virtual address that matches the bottom 32
459 bits of the virtual address used by a recent load at (AArch64) EL1
460 might return incorrect data.
461
462 The workaround is to write the contextidr_el1 register on exception
463 return to a 32-bit task.
464 Please note that this does not necessarily enable the workaround,
465 as it depends on the alternative framework, which will only patch
466 the kernel if an affected CPU is detected.
467
468 If unsure, say Y.
469
470 config ARM64_ERRATUM_843419
471 bool "Cortex-A53: 843419: A load or store might access an incorrect address"
472 default y
473 select ARM64_MODULE_PLTS if MODULES
474 help
475 This option links the kernel with '--fix-cortex-a53-843419' and
476 enables PLT support to replace certain ADRP instructions, which can
477 cause subsequent memory accesses to use an incorrect address on
478 Cortex-A53 parts up to r0p4.
479
480 If unsure, say Y.
481
482 config ARM64_ERRATUM_1024718
483 bool "Cortex-A55: 1024718: Update of DBM/AP bits without break before make might result in incorrect update"
484 default y
485 help
486 This option adds work around for Arm Cortex-A55 Erratum 1024718.
487
488 Affected Cortex-A55 cores (r0p0, r0p1, r1p0) could cause incorrect
489 update of the hardware dirty bit when the DBM/AP bits are updated
490 without a break-before-make. The work around is to disable the usage
491 of hardware DBM locally on the affected cores. CPUs not affected by
492 erratum will continue to use the feature.
493
494 If unsure, say Y.
495
496 config ARM64_ERRATUM_1188873
497 bool "Cortex-A76: MRC read following MRRC read of specific Generic Timer in AArch32 might give incorrect result"
498 default y
499 select ARM_ARCH_TIMER_OOL_WORKAROUND
500 help
501 This option adds work arounds for ARM Cortex-A76 erratum 1188873
502
503 Affected Cortex-A76 cores (r0p0, r1p0, r2p0) could cause
504 register corruption when accessing the timer registers from
505 AArch32 userspace.
506
507 If unsure, say Y.
508
509 config ARM64_ERRATUM_1165522
510 bool "Cortex-A76: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
511 default y
512 help
513 This option adds work arounds for ARM Cortex-A76 erratum 1165522
514
515 Affected Cortex-A76 cores (r0p0, r1p0, r2p0) could end-up with
516 corrupted TLBs by speculating an AT instruction during a guest
517 context switch.
518
519 If unsure, say Y.
520
521 config ARM64_ERRATUM_1286807
522 bool "Cortex-A76: Modification of the translation table for a virtual address might lead to read-after-read ordering violation"
523 default y
524 select ARM64_WORKAROUND_REPEAT_TLBI
525 help
526 This option adds workaround for ARM Cortex-A76 erratum 1286807
527
528 On the affected Cortex-A76 cores (r0p0 to r3p0), if a virtual
529 address for a cacheable mapping of a location is being
530 accessed by a core while another core is remapping the virtual
531 address to a new physical page using the recommended
532 break-before-make sequence, then under very rare circumstances
533 TLBI+DSB completes before a read using the translation being
534 invalidated has been observed by other observers. The
535 workaround repeats the TLBI+DSB operation.
536
537 If unsure, say Y.
538
539 config CAVIUM_ERRATUM_22375
540 bool "Cavium erratum 22375, 24313"
541 default y
542 help
543 Enable workaround for erratum 22375, 24313.
544
545 This implements two gicv3-its errata workarounds for ThunderX. Both
546 with small impact affecting only ITS table allocation.
547
548 erratum 22375: only alloc 8MB table size
549 erratum 24313: ignore memory access type
550
551 The fixes are in ITS initialization and basically ignore memory access
552 type and table size provided by the TYPER and BASER registers.
553
554 If unsure, say Y.
555
556 config CAVIUM_ERRATUM_23144
557 bool "Cavium erratum 23144: ITS SYNC hang on dual socket system"
558 depends on NUMA
559 default y
560 help
561 ITS SYNC command hang for cross node io and collections/cpu mapping.
562
563 If unsure, say Y.
564
565 config CAVIUM_ERRATUM_23154
566 bool "Cavium erratum 23154: Access to ICC_IAR1_EL1 is not sync'ed"
567 default y
568 help
569 The gicv3 of ThunderX requires a modified version for
570 reading the IAR status to ensure data synchronization
571 (access to icc_iar1_el1 is not sync'ed before and after).
572
573 If unsure, say Y.
574
575 config CAVIUM_ERRATUM_27456
576 bool "Cavium erratum 27456: Broadcast TLBI instructions may cause icache corruption"
577 default y
578 help
579 On ThunderX T88 pass 1.x through 2.1 parts, broadcast TLBI
580 instructions may cause the icache to become corrupted if it
581 contains data for a non-current ASID. The fix is to
582 invalidate the icache when changing the mm context.
583
584 If unsure, say Y.
585
586 config CAVIUM_ERRATUM_30115
587 bool "Cavium erratum 30115: Guest may disable interrupts in host"
588 default y
589 help
590 On ThunderX T88 pass 1.x through 2.2, T81 pass 1.0 through
591 1.2, and T83 Pass 1.0, KVM guest execution may disable
592 interrupts in host. Trapping both GICv3 group-0 and group-1
593 accesses sidesteps the issue.
594
595 If unsure, say Y.
596
597 config QCOM_FALKOR_ERRATUM_1003
598 bool "Falkor E1003: Incorrect translation due to ASID change"
599 default y
600 help
601 On Falkor v1, an incorrect ASID may be cached in the TLB when ASID
602 and BADDR are changed together in TTBRx_EL1. Since we keep the ASID
603 in TTBR1_EL1, this situation only occurs in the entry trampoline and
604 then only for entries in the walk cache, since the leaf translation
605 is unchanged. Work around the erratum by invalidating the walk cache
606 entries for the trampoline before entering the kernel proper.
607
608 config ARM64_WORKAROUND_REPEAT_TLBI
609 bool
610 help
611 Enable the repeat TLBI workaround for Falkor erratum 1009 and
612 Cortex-A76 erratum 1286807.
613
614 config QCOM_FALKOR_ERRATUM_1009
615 bool "Falkor E1009: Prematurely complete a DSB after a TLBI"
616 default y
617 select ARM64_WORKAROUND_REPEAT_TLBI
618 help
619 On Falkor v1, the CPU may prematurely complete a DSB following a
620 TLBI xxIS invalidate maintenance operation. Repeat the TLBI operation
621 one more time to fix the issue.
622
623 If unsure, say Y.
624
625 config QCOM_QDF2400_ERRATUM_0065
626 bool "QDF2400 E0065: Incorrect GITS_TYPER.ITT_Entry_size"
627 default y
628 help
629 On Qualcomm Datacenter Technologies QDF2400 SoC, ITS hardware reports
630 ITE size incorrectly. The GITS_TYPER.ITT_Entry_size field should have
631 been indicated as 16Bytes (0xf), not 8Bytes (0x7).
632
633 If unsure, say Y.
634
635 config SOCIONEXT_SYNQUACER_PREITS
636 bool "Socionext Synquacer: Workaround for GICv3 pre-ITS"
637 default y
638 help
639 Socionext Synquacer SoCs implement a separate h/w block to generate
640 MSI doorbell writes with non-zero values for the device ID.
641
642 If unsure, say Y.
643
644 config HISILICON_ERRATUM_161600802
645 bool "Hip07 161600802: Erroneous redistributor VLPI base"
646 default y
647 help
648 The HiSilicon Hip07 SoC usees the wrong redistributor base
649 when issued ITS commands such as VMOVP and VMAPP, and requires
650 a 128kB offset to be applied to the target address in this commands.
651
652 If unsure, say Y.
653
654 config QCOM_FALKOR_ERRATUM_E1041
655 bool "Falkor E1041: Speculative instruction fetches might cause errant memory access"
656 default y
657 help
658 Falkor CPU may speculatively fetch instructions from an improper
659 memory location when MMU translation is changed from SCTLR_ELn[M]=1
660 to SCTLR_ELn[M]=0. Prefix an ISB instruction to fix the problem.
661
662 If unsure, say Y.
663
664 endmenu
665
666
667 choice
668 prompt "Page size"
669 default ARM64_4K_PAGES
670 help
671 Page size (translation granule) configuration.
672
673 config ARM64_4K_PAGES
674 bool "4KB"
675 help
676 This feature enables 4KB pages support.
677
678 config ARM64_16K_PAGES
679 bool "16KB"
680 help
681 The system will use 16KB pages support. AArch32 emulation
682 requires applications compiled with 16K (or a multiple of 16K)
683 aligned segments.
684
685 config ARM64_64K_PAGES
686 bool "64KB"
687 help
688 This feature enables 64KB pages support (4KB by default)
689 allowing only two levels of page tables and faster TLB
690 look-up. AArch32 emulation requires applications compiled
691 with 64K aligned segments.
692
693 endchoice
694
695 choice
696 prompt "Virtual address space size"
697 default ARM64_VA_BITS_39 if ARM64_4K_PAGES
698 default ARM64_VA_BITS_47 if ARM64_16K_PAGES
699 default ARM64_VA_BITS_42 if ARM64_64K_PAGES
700 help
701 Allows choosing one of multiple possible virtual address
702 space sizes. The level of translation table is determined by
703 a combination of page size and virtual address space size.
704
705 config ARM64_VA_BITS_36
706 bool "36-bit" if EXPERT
707 depends on ARM64_16K_PAGES
708
709 config ARM64_VA_BITS_39
710 bool "39-bit"
711 depends on ARM64_4K_PAGES
712
713 config ARM64_VA_BITS_42
714 bool "42-bit"
715 depends on ARM64_64K_PAGES
716
717 config ARM64_VA_BITS_47
718 bool "47-bit"
719 depends on ARM64_16K_PAGES
720
721 config ARM64_VA_BITS_48
722 bool "48-bit"
723
724 config ARM64_USER_VA_BITS_52
725 bool "52-bit (user)"
726 depends on ARM64_64K_PAGES && (ARM64_PAN || !ARM64_SW_TTBR0_PAN)
727 help
728 Enable 52-bit virtual addressing for userspace when explicitly
729 requested via a hint to mmap(). The kernel will continue to
730 use 48-bit virtual addresses for its own mappings.
731
732 NOTE: Enabling 52-bit virtual addressing in conjunction with
733 ARMv8.3 Pointer Authentication will result in the PAC being
734 reduced from 7 bits to 3 bits, which may have a significant
735 impact on its susceptibility to brute-force attacks.
736
737 If unsure, select 48-bit virtual addressing instead.
738
739 endchoice
740
741 config ARM64_FORCE_52BIT
742 bool "Force 52-bit virtual addresses for userspace"
743 depends on ARM64_USER_VA_BITS_52 && EXPERT
744 help
745 For systems with 52-bit userspace VAs enabled, the kernel will attempt
746 to maintain compatibility with older software by providing 48-bit VAs
747 unless a hint is supplied to mmap.
748
749 This configuration option disables the 48-bit compatibility logic, and
750 forces all userspace addresses to be 52-bit on HW that supports it. One
751 should only enable this configuration option for stress testing userspace
752 memory management code. If unsure say N here.
753
754 config ARM64_VA_BITS
755 int
756 default 36 if ARM64_VA_BITS_36
757 default 39 if ARM64_VA_BITS_39
758 default 42 if ARM64_VA_BITS_42
759 default 47 if ARM64_VA_BITS_47
760 default 48 if ARM64_VA_BITS_48 || ARM64_USER_VA_BITS_52
761
762 choice
763 prompt "Physical address space size"
764 default ARM64_PA_BITS_48
765 help
766 Choose the maximum physical address range that the kernel will
767 support.
768
769 config ARM64_PA_BITS_48
770 bool "48-bit"
771
772 config ARM64_PA_BITS_52
773 bool "52-bit (ARMv8.2)"
774 depends on ARM64_64K_PAGES
775 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
776 help
777 Enable support for a 52-bit physical address space, introduced as
778 part of the ARMv8.2-LPA extension.
779
780 With this enabled, the kernel will also continue to work on CPUs that
781 do not support ARMv8.2-LPA, but with some added memory overhead (and
782 minor performance overhead).
783
784 endchoice
785
786 config ARM64_PA_BITS
787 int
788 default 48 if ARM64_PA_BITS_48
789 default 52 if ARM64_PA_BITS_52
790
791 config CPU_BIG_ENDIAN
792 bool "Build big-endian kernel"
793 help
794 Say Y if you plan on running a kernel in big-endian mode.
795
796 config SCHED_MC
797 bool "Multi-core scheduler support"
798 help
799 Multi-core scheduler support improves the CPU scheduler's decision
800 making when dealing with multi-core CPU chips at a cost of slightly
801 increased overhead in some places. If unsure say N here.
802
803 config SCHED_SMT
804 bool "SMT scheduler support"
805 help
806 Improves the CPU scheduler's decision making when dealing with
807 MultiThreading at a cost of slightly increased overhead in some
808 places. If unsure say N here.
809
810 config NR_CPUS
811 int "Maximum number of CPUs (2-4096)"
812 range 2 4096
813 # These have to remain sorted largest to smallest
814 default "64"
815
816 config HOTPLUG_CPU
817 bool "Support for hot-pluggable CPUs"
818 select GENERIC_IRQ_MIGRATION
819 help
820 Say Y here to experiment with turning CPUs off and on. CPUs
821 can be controlled through /sys/devices/system/cpu.
822
823 # Common NUMA Features
824 config NUMA
825 bool "Numa Memory Allocation and Scheduler Support"
826 select ACPI_NUMA if ACPI
827 select OF_NUMA
828 help
829 Enable NUMA (Non Uniform Memory Access) support.
830
831 The kernel will try to allocate memory used by a CPU on the
832 local memory of the CPU and add some more
833 NUMA awareness to the kernel.
834
835 config NODES_SHIFT
836 int "Maximum NUMA Nodes (as a power of 2)"
837 range 1 10
838 default "2"
839 depends on NEED_MULTIPLE_NODES
840 help
841 Specify the maximum number of NUMA Nodes available on the target
842 system. Increases memory reserved to accommodate various tables.
843
844 config USE_PERCPU_NUMA_NODE_ID
845 def_bool y
846 depends on NUMA
847
848 config HAVE_SETUP_PER_CPU_AREA
849 def_bool y
850 depends on NUMA
851
852 config NEED_PER_CPU_EMBED_FIRST_CHUNK
853 def_bool y
854 depends on NUMA
855
856 config HOLES_IN_ZONE
857 def_bool y
858
859 source kernel/Kconfig.hz
860
861 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
862 def_bool y
863
864 config ARCH_SPARSEMEM_ENABLE
865 def_bool y
866 select SPARSEMEM_VMEMMAP_ENABLE
867
868 config ARCH_SPARSEMEM_DEFAULT
869 def_bool ARCH_SPARSEMEM_ENABLE
870
871 config ARCH_SELECT_MEMORY_MODEL
872 def_bool ARCH_SPARSEMEM_ENABLE
873
874 config ARCH_FLATMEM_ENABLE
875 def_bool !NUMA
876
877 config HAVE_ARCH_PFN_VALID
878 def_bool y
879
880 config HW_PERF_EVENTS
881 def_bool y
882 depends on ARM_PMU
883
884 config SYS_SUPPORTS_HUGETLBFS
885 def_bool y
886
887 config ARCH_WANT_HUGE_PMD_SHARE
888 def_bool y if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
889
890 config ARCH_HAS_CACHE_LINE_SIZE
891 def_bool y
892
893 config SECCOMP
894 bool "Enable seccomp to safely compute untrusted bytecode"
895 ---help---
896 This kernel feature is useful for number crunching applications
897 that may need to compute untrusted bytecode during their
898 execution. By using pipes or other transports made available to
899 the process as file descriptors supporting the read/write
900 syscalls, it's possible to isolate those applications in
901 their own address space using seccomp. Once seccomp is
902 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
903 and the task is only allowed to execute a few safe syscalls
904 defined by each seccomp mode.
905
906 config PARAVIRT
907 bool "Enable paravirtualization code"
908 help
909 This changes the kernel so it can modify itself when it is run
910 under a hypervisor, potentially improving performance significantly
911 over full virtualization.
912
913 config PARAVIRT_TIME_ACCOUNTING
914 bool "Paravirtual steal time accounting"
915 select PARAVIRT
916 default n
917 help
918 Select this option to enable fine granularity task steal time
919 accounting. Time spent executing other tasks in parallel with
920 the current vCPU is discounted from the vCPU power. To account for
921 that, there can be a small performance impact.
922
923 If in doubt, say N here.
924
925 config KEXEC
926 depends on PM_SLEEP_SMP
927 select KEXEC_CORE
928 bool "kexec system call"
929 ---help---
930 kexec is a system call that implements the ability to shutdown your
931 current kernel, and to start another kernel. It is like a reboot
932 but it is independent of the system firmware. And like a reboot
933 you can start any kernel with it, not just Linux.
934
935 config KEXEC_FILE
936 bool "kexec file based system call"
937 select KEXEC_CORE
938 help
939 This is new version of kexec system call. This system call is
940 file based and takes file descriptors as system call argument
941 for kernel and initramfs as opposed to list of segments as
942 accepted by previous system call.
943
944 config KEXEC_VERIFY_SIG
945 bool "Verify kernel signature during kexec_file_load() syscall"
946 depends on KEXEC_FILE
947 help
948 Select this option to verify a signature with loaded kernel
949 image. If configured, any attempt of loading a image without
950 valid signature will fail.
951
952 In addition to that option, you need to enable signature
953 verification for the corresponding kernel image type being
954 loaded in order for this to work.
955
956 config KEXEC_IMAGE_VERIFY_SIG
957 bool "Enable Image signature verification support"
958 default y
959 depends on KEXEC_VERIFY_SIG
960 depends on EFI && SIGNED_PE_FILE_VERIFICATION
961 help
962 Enable Image signature verification support.
963
964 comment "Support for PE file signature verification disabled"
965 depends on KEXEC_VERIFY_SIG
966 depends on !EFI || !SIGNED_PE_FILE_VERIFICATION
967
968 config CRASH_DUMP
969 bool "Build kdump crash kernel"
970 help
971 Generate crash dump after being started by kexec. This should
972 be normally only set in special crash dump kernels which are
973 loaded in the main kernel with kexec-tools into a specially
974 reserved region and then later executed after a crash by
975 kdump/kexec.
976
977 For more details see Documentation/kdump/kdump.txt
978
979 config XEN_DOM0
980 def_bool y
981 depends on XEN
982
983 config XEN
984 bool "Xen guest support on ARM64"
985 depends on ARM64 && OF
986 select SWIOTLB_XEN
987 select PARAVIRT
988 help
989 Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64.
990
991 config FORCE_MAX_ZONEORDER
992 int
993 default "14" if (ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE)
994 default "12" if (ARM64_16K_PAGES && TRANSPARENT_HUGEPAGE)
995 default "11"
996 help
997 The kernel memory allocator divides physically contiguous memory
998 blocks into "zones", where each zone is a power of two number of
999 pages. This option selects the largest power of two that the kernel
1000 keeps in the memory allocator. If you need to allocate very large
1001 blocks of physically contiguous memory, then you may need to
1002 increase this value.
1003
1004 This config option is actually maximum order plus one. For example,
1005 a value of 11 means that the largest free memory block is 2^10 pages.
1006
1007 We make sure that we can allocate upto a HugePage size for each configuration.
1008 Hence we have :
1009 MAX_ORDER = (PMD_SHIFT - PAGE_SHIFT) + 1 => PAGE_SHIFT - 2
1010
1011 However for 4K, we choose a higher default value, 11 as opposed to 10, giving us
1012 4M allocations matching the default size used by generic code.
1013
1014 config UNMAP_KERNEL_AT_EL0
1015 bool "Unmap kernel when running in userspace (aka \"KAISER\")" if EXPERT
1016 default y
1017 help
1018 Speculation attacks against some high-performance processors can
1019 be used to bypass MMU permission checks and leak kernel data to
1020 userspace. This can be defended against by unmapping the kernel
1021 when running in userspace, mapping it back in on exception entry
1022 via a trampoline page in the vector table.
1023
1024 If unsure, say Y.
1025
1026 config HARDEN_BRANCH_PREDICTOR
1027 bool "Harden the branch predictor against aliasing attacks" if EXPERT
1028 default y
1029 help
1030 Speculation attacks against some high-performance processors rely on
1031 being able to manipulate the branch predictor for a victim context by
1032 executing aliasing branches in the attacker context. Such attacks
1033 can be partially mitigated against by clearing internal branch
1034 predictor state and limiting the prediction logic in some situations.
1035
1036 This config option will take CPU-specific actions to harden the
1037 branch predictor against aliasing attacks and may rely on specific
1038 instruction sequences or control bits being set by the system
1039 firmware.
1040
1041 If unsure, say Y.
1042
1043 config HARDEN_EL2_VECTORS
1044 bool "Harden EL2 vector mapping against system register leak" if EXPERT
1045 default y
1046 help
1047 Speculation attacks against some high-performance processors can
1048 be used to leak privileged information such as the vector base
1049 register, resulting in a potential defeat of the EL2 layout
1050 randomization.
1051
1052 This config option will map the vectors to a fixed location,
1053 independent of the EL2 code mapping, so that revealing VBAR_EL2
1054 to an attacker does not give away any extra information. This
1055 only gets enabled on affected CPUs.
1056
1057 If unsure, say Y.
1058
1059 config ARM64_SSBD
1060 bool "Speculative Store Bypass Disable" if EXPERT
1061 default y
1062 help
1063 This enables mitigation of the bypassing of previous stores
1064 by speculative loads.
1065
1066 If unsure, say Y.
1067
1068 config RODATA_FULL_DEFAULT_ENABLED
1069 bool "Apply r/o permissions of VM areas also to their linear aliases"
1070 default y
1071 help
1072 Apply read-only attributes of VM areas to the linear alias of
1073 the backing pages as well. This prevents code or read-only data
1074 from being modified (inadvertently or intentionally) via another
1075 mapping of the same memory page. This additional enhancement can
1076 be turned off at runtime by passing rodata=[off|on] (and turned on
1077 with rodata=full if this option is set to 'n')
1078
1079 This requires the linear region to be mapped down to pages,
1080 which may adversely affect performance in some cases.
1081
1082 menuconfig ARMV8_DEPRECATED
1083 bool "Emulate deprecated/obsolete ARMv8 instructions"
1084 depends on COMPAT
1085 depends on SYSCTL
1086 help
1087 Legacy software support may require certain instructions
1088 that have been deprecated or obsoleted in the architecture.
1089
1090 Enable this config to enable selective emulation of these
1091 features.
1092
1093 If unsure, say Y
1094
1095 if ARMV8_DEPRECATED
1096
1097 config SWP_EMULATION
1098 bool "Emulate SWP/SWPB instructions"
1099 help
1100 ARMv8 obsoletes the use of A32 SWP/SWPB instructions such that
1101 they are always undefined. Say Y here to enable software
1102 emulation of these instructions for userspace using LDXR/STXR.
1103
1104 In some older versions of glibc [<=2.8] SWP is used during futex
1105 trylock() operations with the assumption that the code will not
1106 be preempted. This invalid assumption may be more likely to fail
1107 with SWP emulation enabled, leading to deadlock of the user
1108 application.
1109
1110 NOTE: when accessing uncached shared regions, LDXR/STXR rely
1111 on an external transaction monitoring block called a global
1112 monitor to maintain update atomicity. If your system does not
1113 implement a global monitor, this option can cause programs that
1114 perform SWP operations to uncached memory to deadlock.
1115
1116 If unsure, say Y
1117
1118 config CP15_BARRIER_EMULATION
1119 bool "Emulate CP15 Barrier instructions"
1120 help
1121 The CP15 barrier instructions - CP15ISB, CP15DSB, and
1122 CP15DMB - are deprecated in ARMv8 (and ARMv7). It is
1123 strongly recommended to use the ISB, DSB, and DMB
1124 instructions instead.
1125
1126 Say Y here to enable software emulation of these
1127 instructions for AArch32 userspace code. When this option is
1128 enabled, CP15 barrier usage is traced which can help
1129 identify software that needs updating.
1130
1131 If unsure, say Y
1132
1133 config SETEND_EMULATION
1134 bool "Emulate SETEND instruction"
1135 help
1136 The SETEND instruction alters the data-endianness of the
1137 AArch32 EL0, and is deprecated in ARMv8.
1138
1139 Say Y here to enable software emulation of the instruction
1140 for AArch32 userspace code.
1141
1142 Note: All the cpus on the system must have mixed endian support at EL0
1143 for this feature to be enabled. If a new CPU - which doesn't support mixed
1144 endian - is hotplugged in after this feature has been enabled, there could
1145 be unexpected results in the applications.
1146
1147 If unsure, say Y
1148 endif
1149
1150 config ARM64_SW_TTBR0_PAN
1151 bool "Emulate Privileged Access Never using TTBR0_EL1 switching"
1152 help
1153 Enabling this option prevents the kernel from accessing
1154 user-space memory directly by pointing TTBR0_EL1 to a reserved
1155 zeroed area and reserved ASID. The user access routines
1156 restore the valid TTBR0_EL1 temporarily.
1157
1158 menu "ARMv8.1 architectural features"
1159
1160 config ARM64_HW_AFDBM
1161 bool "Support for hardware updates of the Access and Dirty page flags"
1162 default y
1163 help
1164 The ARMv8.1 architecture extensions introduce support for
1165 hardware updates of the access and dirty information in page
1166 table entries. When enabled in TCR_EL1 (HA and HD bits) on
1167 capable processors, accesses to pages with PTE_AF cleared will
1168 set this bit instead of raising an access flag fault.
1169 Similarly, writes to read-only pages with the DBM bit set will
1170 clear the read-only bit (AP[2]) instead of raising a
1171 permission fault.
1172
1173 Kernels built with this configuration option enabled continue
1174 to work on pre-ARMv8.1 hardware and the performance impact is
1175 minimal. If unsure, say Y.
1176
1177 config ARM64_PAN
1178 bool "Enable support for Privileged Access Never (PAN)"
1179 default y
1180 help
1181 Privileged Access Never (PAN; part of the ARMv8.1 Extensions)
1182 prevents the kernel or hypervisor from accessing user-space (EL0)
1183 memory directly.
1184
1185 Choosing this option will cause any unprotected (not using
1186 copy_to_user et al) memory access to fail with a permission fault.
1187
1188 The feature is detected at runtime, and will remain as a 'nop'
1189 instruction if the cpu does not implement the feature.
1190
1191 config ARM64_LSE_ATOMICS
1192 bool "Atomic instructions"
1193 default y
1194 help
1195 As part of the Large System Extensions, ARMv8.1 introduces new
1196 atomic instructions that are designed specifically to scale in
1197 very large systems.
1198
1199 Say Y here to make use of these instructions for the in-kernel
1200 atomic routines. This incurs a small overhead on CPUs that do
1201 not support these instructions and requires the kernel to be
1202 built with binutils >= 2.25 in order for the new instructions
1203 to be used.
1204
1205 config ARM64_VHE
1206 bool "Enable support for Virtualization Host Extensions (VHE)"
1207 default y
1208 help
1209 Virtualization Host Extensions (VHE) allow the kernel to run
1210 directly at EL2 (instead of EL1) on processors that support
1211 it. This leads to better performance for KVM, as they reduce
1212 the cost of the world switch.
1213
1214 Selecting this option allows the VHE feature to be detected
1215 at runtime, and does not affect processors that do not
1216 implement this feature.
1217
1218 endmenu
1219
1220 menu "ARMv8.2 architectural features"
1221
1222 config ARM64_UAO
1223 bool "Enable support for User Access Override (UAO)"
1224 default y
1225 help
1226 User Access Override (UAO; part of the ARMv8.2 Extensions)
1227 causes the 'unprivileged' variant of the load/store instructions to
1228 be overridden to be privileged.
1229
1230 This option changes get_user() and friends to use the 'unprivileged'
1231 variant of the load/store instructions. This ensures that user-space
1232 really did have access to the supplied memory. When addr_limit is
1233 set to kernel memory the UAO bit will be set, allowing privileged
1234 access to kernel memory.
1235
1236 Choosing this option will cause copy_to_user() et al to use user-space
1237 memory permissions.
1238
1239 The feature is detected at runtime, the kernel will use the
1240 regular load/store instructions if the cpu does not implement the
1241 feature.
1242
1243 config ARM64_PMEM
1244 bool "Enable support for persistent memory"
1245 select ARCH_HAS_PMEM_API
1246 select ARCH_HAS_UACCESS_FLUSHCACHE
1247 help
1248 Say Y to enable support for the persistent memory API based on the
1249 ARMv8.2 DCPoP feature.
1250
1251 The feature is detected at runtime, and the kernel will use DC CVAC
1252 operations if DC CVAP is not supported (following the behaviour of
1253 DC CVAP itself if the system does not define a point of persistence).
1254
1255 config ARM64_RAS_EXTN
1256 bool "Enable support for RAS CPU Extensions"
1257 default y
1258 help
1259 CPUs that support the Reliability, Availability and Serviceability
1260 (RAS) Extensions, part of ARMv8.2 are able to track faults and
1261 errors, classify them and report them to software.
1262
1263 On CPUs with these extensions system software can use additional
1264 barriers to determine if faults are pending and read the
1265 classification from a new set of registers.
1266
1267 Selecting this feature will allow the kernel to use these barriers
1268 and access the new registers if the system supports the extension.
1269 Platform RAS features may additionally depend on firmware support.
1270
1271 config ARM64_CNP
1272 bool "Enable support for Common Not Private (CNP) translations"
1273 default y
1274 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
1275 help
1276 Common Not Private (CNP) allows translation table entries to
1277 be shared between different PEs in the same inner shareable
1278 domain, so the hardware can use this fact to optimise the
1279 caching of such entries in the TLB.
1280
1281 Selecting this option allows the CNP feature to be detected
1282 at runtime, and does not affect PEs that do not implement
1283 this feature.
1284
1285 endmenu
1286
1287 menu "ARMv8.3 architectural features"
1288
1289 config ARM64_PTR_AUTH
1290 bool "Enable support for pointer authentication"
1291 default y
1292 help
1293 Pointer authentication (part of the ARMv8.3 Extensions) provides
1294 instructions for signing and authenticating pointers against secret
1295 keys, which can be used to mitigate Return Oriented Programming (ROP)
1296 and other attacks.
1297
1298 This option enables these instructions at EL0 (i.e. for userspace).
1299
1300 Choosing this option will cause the kernel to initialise secret keys
1301 for each process at exec() time, with these keys being
1302 context-switched along with the process.
1303
1304 The feature is detected at runtime. If the feature is not present in
1305 hardware it will not be advertised to userspace nor will it be
1306 enabled.
1307
1308 endmenu
1309
1310 config ARM64_SVE
1311 bool "ARM Scalable Vector Extension support"
1312 default y
1313 depends on !KVM || ARM64_VHE
1314 help
1315 The Scalable Vector Extension (SVE) is an extension to the AArch64
1316 execution state which complements and extends the SIMD functionality
1317 of the base architecture to support much larger vectors and to enable
1318 additional vectorisation opportunities.
1319
1320 To enable use of this extension on CPUs that implement it, say Y.
1321
1322 Note that for architectural reasons, firmware _must_ implement SVE
1323 support when running on SVE capable hardware. The required support
1324 is present in:
1325
1326 * version 1.5 and later of the ARM Trusted Firmware
1327 * the AArch64 boot wrapper since commit 5e1261e08abf
1328 ("bootwrapper: SVE: Enable SVE for EL2 and below").
1329
1330 For other firmware implementations, consult the firmware documentation
1331 or vendor.
1332
1333 If you need the kernel to boot on SVE-capable hardware with broken
1334 firmware, you may need to say N here until you get your firmware
1335 fixed. Otherwise, you may experience firmware panics or lockups when
1336 booting the kernel. If unsure and you are not observing these
1337 symptoms, you should assume that it is safe to say Y.
1338
1339 CPUs that support SVE are architecturally required to support the
1340 Virtualization Host Extensions (VHE), so the kernel makes no
1341 provision for supporting SVE alongside KVM without VHE enabled.
1342 Thus, you will need to enable CONFIG_ARM64_VHE if you want to support
1343 KVM in the same kernel image.
1344
1345 config ARM64_MODULE_PLTS
1346 bool
1347 select HAVE_MOD_ARCH_SPECIFIC
1348
1349 config RELOCATABLE
1350 bool
1351 help
1352 This builds the kernel as a Position Independent Executable (PIE),
1353 which retains all relocation metadata required to relocate the
1354 kernel binary at runtime to a different virtual address than the
1355 address it was linked at.
1356 Since AArch64 uses the RELA relocation format, this requires a
1357 relocation pass at runtime even if the kernel is loaded at the
1358 same address it was linked at.
1359
1360 config RANDOMIZE_BASE
1361 bool "Randomize the address of the kernel image"
1362 select ARM64_MODULE_PLTS if MODULES
1363 select RELOCATABLE
1364 help
1365 Randomizes the virtual address at which the kernel image is
1366 loaded, as a security feature that deters exploit attempts
1367 relying on knowledge of the location of kernel internals.
1368
1369 It is the bootloader's job to provide entropy, by passing a
1370 random u64 value in /chosen/kaslr-seed at kernel entry.
1371
1372 When booting via the UEFI stub, it will invoke the firmware's
1373 EFI_RNG_PROTOCOL implementation (if available) to supply entropy
1374 to the kernel proper. In addition, it will randomise the physical
1375 location of the kernel Image as well.
1376
1377 If unsure, say N.
1378
1379 config RANDOMIZE_MODULE_REGION_FULL
1380 bool "Randomize the module region over a 4 GB range"
1381 depends on RANDOMIZE_BASE
1382 default y
1383 help
1384 Randomizes the location of the module region inside a 4 GB window
1385 covering the core kernel. This way, it is less likely for modules
1386 to leak information about the location of core kernel data structures
1387 but it does imply that function calls between modules and the core
1388 kernel will need to be resolved via veneers in the module PLT.
1389
1390 When this option is not set, the module region will be randomized over
1391 a limited range that contains the [_stext, _etext] interval of the
1392 core kernel, so branch relocations are always in range.
1393
1394 config CC_HAVE_STACKPROTECTOR_SYSREG
1395 def_bool $(cc-option,-mstack-protector-guard=sysreg -mstack-protector-guard-reg=sp_el0 -mstack-protector-guard-offset=0)
1396
1397 config STACKPROTECTOR_PER_TASK
1398 def_bool y
1399 depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_SYSREG
1400
1401 endmenu
1402
1403 menu "Boot options"
1404
1405 config ARM64_ACPI_PARKING_PROTOCOL
1406 bool "Enable support for the ARM64 ACPI parking protocol"
1407 depends on ACPI
1408 help
1409 Enable support for the ARM64 ACPI parking protocol. If disabled
1410 the kernel will not allow booting through the ARM64 ACPI parking
1411 protocol even if the corresponding data is present in the ACPI
1412 MADT table.
1413
1414 config CMDLINE
1415 string "Default kernel command string"
1416 default ""
1417 help
1418 Provide a set of default command-line options at build time by
1419 entering them here. As a minimum, you should specify the the
1420 root device (e.g. root=/dev/nfs).
1421
1422 config CMDLINE_FORCE
1423 bool "Always use the default kernel command string"
1424 help
1425 Always use the default kernel command string, even if the boot
1426 loader passes other arguments to the kernel.
1427 This is useful if you cannot or don't want to change the
1428 command-line options your boot loader passes to the kernel.
1429
1430 config EFI_STUB
1431 bool
1432
1433 config EFI
1434 bool "UEFI runtime support"
1435 depends on OF && !CPU_BIG_ENDIAN
1436 depends on KERNEL_MODE_NEON
1437 select ARCH_SUPPORTS_ACPI
1438 select LIBFDT
1439 select UCS2_STRING
1440 select EFI_PARAMS_FROM_FDT
1441 select EFI_RUNTIME_WRAPPERS
1442 select EFI_STUB
1443 select EFI_ARMSTUB
1444 default y
1445 help
1446 This option provides support for runtime services provided
1447 by UEFI firmware (such as non-volatile variables, realtime
1448 clock, and platform reset). A UEFI stub is also provided to
1449 allow the kernel to be booted as an EFI application. This
1450 is only useful on systems that have UEFI firmware.
1451
1452 config DMI
1453 bool "Enable support for SMBIOS (DMI) tables"
1454 depends on EFI
1455 default y
1456 help
1457 This enables SMBIOS/DMI feature for systems.
1458
1459 This option is only useful on systems that have UEFI firmware.
1460 However, even with this option, the resultant kernel should
1461 continue to boot on existing non-UEFI platforms.
1462
1463 endmenu
1464
1465 config COMPAT
1466 bool "Kernel support for 32-bit EL0"
1467 depends on ARM64_4K_PAGES || EXPERT
1468 select COMPAT_BINFMT_ELF if BINFMT_ELF
1469 select HAVE_UID16
1470 select OLD_SIGSUSPEND3
1471 select COMPAT_OLD_SIGACTION
1472 help
1473 This option enables support for a 32-bit EL0 running under a 64-bit
1474 kernel at EL1. AArch32-specific components such as system calls,
1475 the user helper functions, VFP support and the ptrace interface are
1476 handled appropriately by the kernel.
1477
1478 If you use a page size other than 4KB (i.e, 16KB or 64KB), please be aware
1479 that you will only be able to execute AArch32 binaries that were compiled
1480 with page size aligned segments.
1481
1482 If you want to execute 32-bit userspace applications, say Y.
1483
1484 config SYSVIPC_COMPAT
1485 def_bool y
1486 depends on COMPAT && SYSVIPC
1487
1488 menu "Power management options"
1489
1490 source "kernel/power/Kconfig"
1491
1492 config ARCH_HIBERNATION_POSSIBLE
1493 def_bool y
1494 depends on CPU_PM
1495
1496 config ARCH_HIBERNATION_HEADER
1497 def_bool y
1498 depends on HIBERNATION
1499
1500 config ARCH_SUSPEND_POSSIBLE
1501 def_bool y
1502
1503 endmenu
1504
1505 menu "CPU Power Management"
1506
1507 source "drivers/cpuidle/Kconfig"
1508
1509 source "drivers/cpufreq/Kconfig"
1510
1511 endmenu
1512
1513 source "drivers/firmware/Kconfig"
1514
1515 source "drivers/acpi/Kconfig"
1516
1517 source "arch/arm64/kvm/Kconfig"
1518
1519 if CRYPTO
1520 source "arch/arm64/crypto/Kconfig"
1521 endif