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1# SPDX-License-Identifier: GPL-2.0-only
2config ARM64
3	def_bool y
4	select ACPI_CCA_REQUIRED if ACPI
5	select ACPI_GENERIC_GSI if ACPI
6	select ACPI_GTDT if ACPI
7	select ACPI_IORT if ACPI
8	select ACPI_REDUCED_HARDWARE_ONLY if ACPI
9	select ACPI_MCFG if (ACPI && PCI)
10	select ACPI_SPCR_TABLE if ACPI
11	select ACPI_PPTT if ACPI
12	select ARCH_HAS_DEBUG_WX
13	select ARCH_BINFMT_ELF_STATE
14	select ARCH_HAS_DEBUG_VIRTUAL
15	select ARCH_HAS_DEBUG_VM_PGTABLE
16	select ARCH_HAS_DEVMEM_IS_ALLOWED
17	select ARCH_HAS_DMA_PREP_COHERENT
18	select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
19	select ARCH_HAS_FAST_MULTIPLIER
20	select ARCH_HAS_FORTIFY_SOURCE
21	select ARCH_HAS_GCOV_PROFILE_ALL
22	select ARCH_HAS_GIGANTIC_PAGE
23	select ARCH_HAS_KCOV
24	select ARCH_HAS_KEEPINITRD
25	select ARCH_HAS_MEMBARRIER_SYNC_CORE
26	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
27	select ARCH_HAS_PTE_DEVMAP
28	select ARCH_HAS_PTE_SPECIAL
29	select ARCH_HAS_SETUP_DMA_OPS
30	select ARCH_HAS_SET_DIRECT_MAP
31	select ARCH_HAS_SET_MEMORY
32	select ARCH_STACKWALK
33	select ARCH_HAS_STRICT_KERNEL_RWX
34	select ARCH_HAS_STRICT_MODULE_RWX
35	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
36	select ARCH_HAS_SYNC_DMA_FOR_CPU
37	select ARCH_HAS_SYSCALL_WRAPPER
38	select ARCH_HAS_TEARDOWN_DMA_OPS if IOMMU_SUPPORT
39	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
40	select ARCH_HAVE_ELF_PROT
41	select ARCH_HAVE_NMI_SAFE_CMPXCHG
42	select ARCH_INLINE_READ_LOCK if !PREEMPTION
43	select ARCH_INLINE_READ_LOCK_BH if !PREEMPTION
44	select ARCH_INLINE_READ_LOCK_IRQ if !PREEMPTION
45	select ARCH_INLINE_READ_LOCK_IRQSAVE if !PREEMPTION
46	select ARCH_INLINE_READ_UNLOCK if !PREEMPTION
47	select ARCH_INLINE_READ_UNLOCK_BH if !PREEMPTION
48	select ARCH_INLINE_READ_UNLOCK_IRQ if !PREEMPTION
49	select ARCH_INLINE_READ_UNLOCK_IRQRESTORE if !PREEMPTION
50	select ARCH_INLINE_WRITE_LOCK if !PREEMPTION
51	select ARCH_INLINE_WRITE_LOCK_BH if !PREEMPTION
52	select ARCH_INLINE_WRITE_LOCK_IRQ if !PREEMPTION
53	select ARCH_INLINE_WRITE_LOCK_IRQSAVE if !PREEMPTION
54	select ARCH_INLINE_WRITE_UNLOCK if !PREEMPTION
55	select ARCH_INLINE_WRITE_UNLOCK_BH if !PREEMPTION
56	select ARCH_INLINE_WRITE_UNLOCK_IRQ if !PREEMPTION
57	select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE if !PREEMPTION
58	select ARCH_INLINE_SPIN_TRYLOCK if !PREEMPTION
59	select ARCH_INLINE_SPIN_TRYLOCK_BH if !PREEMPTION
60	select ARCH_INLINE_SPIN_LOCK if !PREEMPTION
61	select ARCH_INLINE_SPIN_LOCK_BH if !PREEMPTION
62	select ARCH_INLINE_SPIN_LOCK_IRQ if !PREEMPTION
63	select ARCH_INLINE_SPIN_LOCK_IRQSAVE if !PREEMPTION
64	select ARCH_INLINE_SPIN_UNLOCK if !PREEMPTION
65	select ARCH_INLINE_SPIN_UNLOCK_BH if !PREEMPTION
66	select ARCH_INLINE_SPIN_UNLOCK_IRQ if !PREEMPTION
67	select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPTION
68	select ARCH_KEEP_MEMBLOCK
69	select ARCH_USE_CMPXCHG_LOCKREF
70	select ARCH_USE_GNU_PROPERTY
71	select ARCH_USE_QUEUED_RWLOCKS
72	select ARCH_USE_QUEUED_SPINLOCKS
73	select ARCH_USE_SYM_ANNOTATIONS
74	select ARCH_SUPPORTS_MEMORY_FAILURE
75	select ARCH_SUPPORTS_SHADOW_CALL_STACK if CC_HAVE_SHADOW_CALL_STACK
76	select ARCH_SUPPORTS_LTO_CLANG if CPU_LITTLE_ENDIAN
77	select ARCH_SUPPORTS_LTO_CLANG_THIN
78	select ARCH_SUPPORTS_CFI_CLANG
79	select ARCH_SUPPORTS_ATOMIC_RMW
80	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && (GCC_VERSION >= 50000 || CC_IS_CLANG)
81	select ARCH_SUPPORTS_NUMA_BALANCING
82	select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT
83	select ARCH_WANT_DEFAULT_BPF_JIT
84	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
85	select ARCH_WANT_FRAME_POINTERS
86	select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
87	select ARCH_WANT_LD_ORPHAN_WARN
88	select ARCH_HAS_UBSAN_SANITIZE_ALL
89	select ARM_AMBA
90	select ARM_ARCH_TIMER
91	select ARM_GIC
92	select AUDIT_ARCH_COMPAT_GENERIC
93	select ARM_GIC_V2M if PCI
94	select ARM_GIC_V3
95	select ARM_GIC_V3_ITS if PCI
96	select ARM_PSCI_FW
97	select BUILDTIME_TABLE_SORT
98	select CLONE_BACKWARDS
99	select COMMON_CLK
100	select CPU_PM if (SUSPEND || CPU_IDLE)
101	select CRC32
102	select DCACHE_WORD_ACCESS
103	select DMA_DIRECT_REMAP
104	select EDAC_SUPPORT
105	select FRAME_POINTER
106	select GENERIC_ALLOCATOR
107	select GENERIC_ARCH_TOPOLOGY
108	select GENERIC_CLOCKEVENTS
109	select GENERIC_CLOCKEVENTS_BROADCAST
110	select GENERIC_CPU_AUTOPROBE
111	select GENERIC_CPU_VULNERABILITIES
112	select GENERIC_EARLY_IOREMAP
113	select GENERIC_IDLE_POLL_SETUP
114	select GENERIC_IRQ_IPI
115	select GENERIC_IRQ_MULTI_HANDLER
116	select GENERIC_IRQ_PROBE
117	select GENERIC_IRQ_SHOW
118	select GENERIC_IRQ_SHOW_LEVEL
119	select GENERIC_PCI_IOMAP
120	select GENERIC_PTDUMP
121	select GENERIC_SCHED_CLOCK
122	select GENERIC_SMP_IDLE_THREAD
123	select GENERIC_STRNCPY_FROM_USER
124	select GENERIC_STRNLEN_USER
125	select GENERIC_TIME_VSYSCALL
126	select GENERIC_GETTIMEOFDAY
127	select GENERIC_VDSO_TIME_NS
128	select HANDLE_DOMAIN_IRQ
129	select HARDIRQS_SW_RESEND
130	select HAVE_MOVE_PMD
131	select HAVE_PCI
132	select HAVE_ACPI_APEI if (ACPI && EFI)
133	select HAVE_ALIGNED_STRUCT_PAGE if SLUB
134	select HAVE_ARCH_AUDITSYSCALL
135	select HAVE_ARCH_BITREVERSE
136	select HAVE_ARCH_COMPILER_H
137	select HAVE_ARCH_HUGE_VMAP
138	select HAVE_ARCH_JUMP_LABEL
139	select HAVE_ARCH_JUMP_LABEL_RELATIVE
140	select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48)
141	select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN
142	select HAVE_ARCH_KGDB
143	select HAVE_ARCH_MMAP_RND_BITS
144	select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
145	select HAVE_ARCH_PREL32_RELOCATIONS
146	select HAVE_ARCH_SECCOMP_FILTER
147	select HAVE_ARCH_STACKLEAK
148	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
149	select HAVE_ARCH_TRACEHOOK
150	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
151	select HAVE_ARCH_VMAP_STACK
152	select HAVE_ARM_SMCCC
153	select HAVE_ASM_MODVERSIONS
154	select HAVE_EBPF_JIT
155	select HAVE_C_RECORDMCOUNT
156	select HAVE_CMPXCHG_DOUBLE
157	select HAVE_CMPXCHG_LOCAL
158	select HAVE_CONTEXT_TRACKING
159	select HAVE_DEBUG_BUGVERBOSE
160	select HAVE_DEBUG_KMEMLEAK
161	select HAVE_DMA_CONTIGUOUS
162	select HAVE_DYNAMIC_FTRACE
163	select HAVE_DYNAMIC_FTRACE_WITH_REGS \
164		if $(cc-option,-fpatchable-function-entry=2)
165	select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY \
166		if DYNAMIC_FTRACE_WITH_REGS
167	select HAVE_EFFICIENT_UNALIGNED_ACCESS
168	select HAVE_FAST_GUP
169	select HAVE_FTRACE_MCOUNT_RECORD
170	select HAVE_FUNCTION_TRACER
171	select HAVE_FUNCTION_ERROR_INJECTION
172	select HAVE_FUNCTION_GRAPH_TRACER
173	select HAVE_GCC_PLUGINS
174	select HAVE_HW_BREAKPOINT if PERF_EVENTS
175	select HAVE_IRQ_TIME_ACCOUNTING
176	select HAVE_NMI
177	select HAVE_PATA_PLATFORM
178	select HAVE_PERF_EVENTS
179	select HAVE_PERF_REGS
180	select HAVE_PERF_USER_STACK_DUMP
181	select HAVE_REGS_AND_STACK_ACCESS_API
182	select HAVE_FUNCTION_ARG_ACCESS_API
183	select HAVE_FUTEX_CMPXCHG if FUTEX
184	select MMU_GATHER_RCU_TABLE_FREE
185	select HAVE_RSEQ
186	select HAVE_STACKPROTECTOR
187	select HAVE_SYSCALL_TRACEPOINTS
188	select HAVE_KPROBES
189	select HAVE_KRETPROBES
190	select HAVE_GENERIC_VDSO
191	select HOLES_IN_ZONE
192	select IOMMU_DMA if IOMMU_SUPPORT
193	select IRQ_DOMAIN
194	select IRQ_FORCED_THREADING
195	select MODULES_USE_ELF_RELA
196	select NEED_DMA_MAP_STATE
197	select NEED_SG_DMA_LENGTH
198	select OF
199	select OF_EARLY_FLATTREE
200	select PCI_DOMAINS_GENERIC if PCI
201	select PCI_ECAM if (ACPI && PCI)
202	select PCI_SYSCALL if PCI
203	select POWER_RESET
204	select POWER_SUPPLY
205	select SET_FS
206	select SPARSE_IRQ
207	select SWIOTLB
208	select SYSCTL_EXCEPTION_TRACE
209	select THREAD_INFO_IN_TASK
210	help
211	  ARM 64-bit (AArch64) Linux support.
212
213config 64BIT
214	def_bool y
215
216config MMU
217	def_bool y
218
219config ARM64_PAGE_SHIFT
220	int
221	default 16 if ARM64_64K_PAGES
222	default 14 if ARM64_16K_PAGES
223	default 12
224
225config ARM64_CONT_PTE_SHIFT
226	int
227	default 5 if ARM64_64K_PAGES
228	default 7 if ARM64_16K_PAGES
229	default 4
230
231config ARM64_CONT_PMD_SHIFT
232	int
233	default 5 if ARM64_64K_PAGES
234	default 5 if ARM64_16K_PAGES
235	default 4
236
237config ARCH_MMAP_RND_BITS_MIN
238       default 14 if ARM64_64K_PAGES
239       default 16 if ARM64_16K_PAGES
240       default 18
241
242# max bits determined by the following formula:
243#  VA_BITS - PAGE_SHIFT - 3
244config ARCH_MMAP_RND_BITS_MAX
245       default 19 if ARM64_VA_BITS=36
246       default 24 if ARM64_VA_BITS=39
247       default 27 if ARM64_VA_BITS=42
248       default 30 if ARM64_VA_BITS=47
249       default 29 if ARM64_VA_BITS=48 && ARM64_64K_PAGES
250       default 31 if ARM64_VA_BITS=48 && ARM64_16K_PAGES
251       default 33 if ARM64_VA_BITS=48
252       default 14 if ARM64_64K_PAGES
253       default 16 if ARM64_16K_PAGES
254       default 18
255
256config ARCH_MMAP_RND_COMPAT_BITS_MIN
257       default 7 if ARM64_64K_PAGES
258       default 9 if ARM64_16K_PAGES
259       default 11
260
261config ARCH_MMAP_RND_COMPAT_BITS_MAX
262       default 16
263
264config NO_IOPORT_MAP
265	def_bool y if !PCI
266
267config STACKTRACE_SUPPORT
268	def_bool y
269
270config ILLEGAL_POINTER_VALUE
271	hex
272	default 0xdead000000000000
273
274config LOCKDEP_SUPPORT
275	def_bool y
276
277config TRACE_IRQFLAGS_SUPPORT
278	def_bool y
279
280config GENERIC_BUG
281	def_bool y
282	depends on BUG
283
284config GENERIC_BUG_RELATIVE_POINTERS
285	def_bool y
286	depends on GENERIC_BUG
287
288config GENERIC_HWEIGHT
289	def_bool y
290
291config GENERIC_CSUM
292        def_bool y
293
294config GENERIC_CALIBRATE_DELAY
295	def_bool y
296
297config ZONE_DMA
298	bool "Support DMA zone" if EXPERT
299	default y
300
301config ZONE_DMA32
302	bool "Support DMA32 zone" if EXPERT
303	default y
304
305config ARCH_ENABLE_MEMORY_HOTPLUG
306	def_bool y
307
308config ARCH_ENABLE_MEMORY_HOTREMOVE
309	def_bool y
310
311config SMP
312	def_bool y
313
314config KERNEL_MODE_NEON
315	def_bool y
316
317config FIX_EARLYCON_MEM
318	def_bool y
319
320config PGTABLE_LEVELS
321	int
322	default 2 if ARM64_16K_PAGES && ARM64_VA_BITS_36
323	default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42
324	default 3 if ARM64_64K_PAGES && (ARM64_VA_BITS_48 || ARM64_VA_BITS_52)
325	default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39
326	default 3 if ARM64_16K_PAGES && ARM64_VA_BITS_47
327	default 4 if !ARM64_64K_PAGES && ARM64_VA_BITS_48
328
329config ARCH_SUPPORTS_UPROBES
330	def_bool y
331
332config ARCH_PROC_KCORE_TEXT
333	def_bool y
334
335config BROKEN_GAS_INST
336	def_bool !$(as-instr,1:\n.inst 0\n.rept . - 1b\n\nnop\n.endr\n)
337
338config KASAN_SHADOW_OFFSET
339	hex
340	depends on KASAN
341	default 0xdfffa00000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && !KASAN_SW_TAGS
342	default 0xdfffd00000000000 if ARM64_VA_BITS_47 && !KASAN_SW_TAGS
343	default 0xdffffe8000000000 if ARM64_VA_BITS_42 && !KASAN_SW_TAGS
344	default 0xdfffffd000000000 if ARM64_VA_BITS_39 && !KASAN_SW_TAGS
345	default 0xdffffffa00000000 if ARM64_VA_BITS_36 && !KASAN_SW_TAGS
346	default 0xefff900000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && KASAN_SW_TAGS
347	default 0xefffc80000000000 if ARM64_VA_BITS_47 && KASAN_SW_TAGS
348	default 0xeffffe4000000000 if ARM64_VA_BITS_42 && KASAN_SW_TAGS
349	default 0xefffffc800000000 if ARM64_VA_BITS_39 && KASAN_SW_TAGS
350	default 0xeffffff900000000 if ARM64_VA_BITS_36 && KASAN_SW_TAGS
351	default 0xffffffffffffffff
352
353source "arch/arm64/Kconfig.platforms"
354
355menu "Kernel Features"
356
357menu "ARM errata workarounds via the alternatives framework"
358
359config ARM64_WORKAROUND_CLEAN_CACHE
360	bool
361
362config ARM64_ERRATUM_826319
363	bool "Cortex-A53: 826319: System might deadlock if a write cannot complete until read data is accepted"
364	default y
365	select ARM64_WORKAROUND_CLEAN_CACHE
366	help
367	  This option adds an alternative code sequence to work around ARM
368	  erratum 826319 on Cortex-A53 parts up to r0p2 with an AMBA 4 ACE or
369	  AXI master interface and an L2 cache.
370
371	  If a Cortex-A53 uses an AMBA AXI4 ACE interface to other processors
372	  and is unable to accept a certain write via this interface, it will
373	  not progress on read data presented on the read data channel and the
374	  system can deadlock.
375
376	  The workaround promotes data cache clean instructions to
377	  data cache clean-and-invalidate.
378	  Please note that this does not necessarily enable the workaround,
379	  as it depends on the alternative framework, which will only patch
380	  the kernel if an affected CPU is detected.
381
382	  If unsure, say Y.
383
384config ARM64_ERRATUM_827319
385	bool "Cortex-A53: 827319: Data cache clean instructions might cause overlapping transactions to the interconnect"
386	default y
387	select ARM64_WORKAROUND_CLEAN_CACHE
388	help
389	  This option adds an alternative code sequence to work around ARM
390	  erratum 827319 on Cortex-A53 parts up to r0p2 with an AMBA 5 CHI
391	  master interface and an L2 cache.
392
393	  Under certain conditions this erratum can cause a clean line eviction
394	  to occur at the same time as another transaction to the same address
395	  on the AMBA 5 CHI interface, which can cause data corruption if the
396	  interconnect reorders the two transactions.
397
398	  The workaround promotes data cache clean instructions to
399	  data cache clean-and-invalidate.
400	  Please note that this does not necessarily enable the workaround,
401	  as it depends on the alternative framework, which will only patch
402	  the kernel if an affected CPU is detected.
403
404	  If unsure, say Y.
405
406config ARM64_ERRATUM_824069
407	bool "Cortex-A53: 824069: Cache line might not be marked as clean after a CleanShared snoop"
408	default y
409	select ARM64_WORKAROUND_CLEAN_CACHE
410	help
411	  This option adds an alternative code sequence to work around ARM
412	  erratum 824069 on Cortex-A53 parts up to r0p2 when it is connected
413	  to a coherent interconnect.
414
415	  If a Cortex-A53 processor is executing a store or prefetch for
416	  write instruction at the same time as a processor in another
417	  cluster is executing a cache maintenance operation to the same
418	  address, then this erratum might cause a clean cache line to be
419	  incorrectly marked as dirty.
420
421	  The workaround promotes data cache clean instructions to
422	  data cache clean-and-invalidate.
423	  Please note that this option does not necessarily enable the
424	  workaround, as it depends on the alternative framework, which will
425	  only patch the kernel if an affected CPU is detected.
426
427	  If unsure, say Y.
428
429config ARM64_ERRATUM_819472
430	bool "Cortex-A53: 819472: Store exclusive instructions might cause data corruption"
431	default y
432	select ARM64_WORKAROUND_CLEAN_CACHE
433	help
434	  This option adds an alternative code sequence to work around ARM
435	  erratum 819472 on Cortex-A53 parts up to r0p1 with an L2 cache
436	  present when it is connected to a coherent interconnect.
437
438	  If the processor is executing a load and store exclusive sequence at
439	  the same time as a processor in another cluster is executing a cache
440	  maintenance operation to the same address, then this erratum might
441	  cause data corruption.
442
443	  The workaround promotes data cache clean instructions to
444	  data cache clean-and-invalidate.
445	  Please note that this does not necessarily enable the workaround,
446	  as it depends on the alternative framework, which will only patch
447	  the kernel if an affected CPU is detected.
448
449	  If unsure, say Y.
450
451config ARM64_ERRATUM_832075
452	bool "Cortex-A57: 832075: possible deadlock on mixing exclusive memory accesses with device loads"
453	default y
454	help
455	  This option adds an alternative code sequence to work around ARM
456	  erratum 832075 on Cortex-A57 parts up to r1p2.
457
458	  Affected Cortex-A57 parts might deadlock when exclusive load/store
459	  instructions to Write-Back memory are mixed with Device loads.
460
461	  The workaround is to promote device loads to use Load-Acquire
462	  semantics.
463	  Please note that this does not necessarily enable the workaround,
464	  as it depends on the alternative framework, which will only patch
465	  the kernel if an affected CPU is detected.
466
467	  If unsure, say Y.
468
469config ARM64_ERRATUM_834220
470	bool "Cortex-A57: 834220: Stage 2 translation fault might be incorrectly reported in presence of a Stage 1 fault"
471	depends on KVM
472	default y
473	help
474	  This option adds an alternative code sequence to work around ARM
475	  erratum 834220 on Cortex-A57 parts up to r1p2.
476
477	  Affected Cortex-A57 parts might report a Stage 2 translation
478	  fault as the result of a Stage 1 fault for load crossing a
479	  page boundary when there is a permission or device memory
480	  alignment fault at Stage 1 and a translation fault at Stage 2.
481
482	  The workaround is to verify that the Stage 1 translation
483	  doesn't generate a fault before handling the Stage 2 fault.
484	  Please note that this does not necessarily enable the workaround,
485	  as it depends on the alternative framework, which will only patch
486	  the kernel if an affected CPU is detected.
487
488	  If unsure, say Y.
489
490config ARM64_ERRATUM_1742098
491	bool "Cortex-A57/A72: 1742098: ELR recorded incorrectly on interrupt taken between cryptographic instructions in a sequence"
492	depends on COMPAT
493	default y
494	help
495	  This option removes the AES hwcap for aarch32 user-space to
496	  workaround erratum 1742098 on Cortex-A57 and Cortex-A72.
497
498	  Affected parts may corrupt the AES state if an interrupt is
499	  taken between a pair of AES instructions. These instructions
500	  are only present if the cryptography extensions are present.
501	  All software should have a fallback implementation for CPUs
502	  that don't implement the cryptography extensions.
503
504	  If unsure, say Y.
505
506config ARM64_ERRATUM_845719
507	bool "Cortex-A53: 845719: a load might read incorrect data"
508	depends on COMPAT
509	default y
510	help
511	  This option adds an alternative code sequence to work around ARM
512	  erratum 845719 on Cortex-A53 parts up to r0p4.
513
514	  When running a compat (AArch32) userspace on an affected Cortex-A53
515	  part, a load at EL0 from a virtual address that matches the bottom 32
516	  bits of the virtual address used by a recent load at (AArch64) EL1
517	  might return incorrect data.
518
519	  The workaround is to write the contextidr_el1 register on exception
520	  return to a 32-bit task.
521	  Please note that this does not necessarily enable the workaround,
522	  as it depends on the alternative framework, which will only patch
523	  the kernel if an affected CPU is detected.
524
525	  If unsure, say Y.
526
527config ARM64_ERRATUM_843419
528	bool "Cortex-A53: 843419: A load or store might access an incorrect address"
529	default y
530	select ARM64_MODULE_PLTS if MODULES
531	help
532	  This option links the kernel with '--fix-cortex-a53-843419' and
533	  enables PLT support to replace certain ADRP instructions, which can
534	  cause subsequent memory accesses to use an incorrect address on
535	  Cortex-A53 parts up to r0p4.
536
537	  If unsure, say Y.
538
539config ARM64_ERRATUM_1024718
540	bool "Cortex-A55: 1024718: Update of DBM/AP bits without break before make might result in incorrect update"
541	default y
542	help
543	  This option adds a workaround for ARM Cortex-A55 Erratum 1024718.
544
545	  Affected Cortex-A55 cores (all revisions) could cause incorrect
546	  update of the hardware dirty bit when the DBM/AP bits are updated
547	  without a break-before-make. The workaround is to disable the usage
548	  of hardware DBM locally on the affected cores. CPUs not affected by
549	  this erratum will continue to use the feature.
550
551	  If unsure, say Y.
552
553config ARM64_ERRATUM_1418040
554	bool "Cortex-A76/Neoverse-N1: MRC read following MRRC read of specific Generic Timer in AArch32 might give incorrect result"
555	default y
556	depends on COMPAT
557	help
558	  This option adds a workaround for ARM Cortex-A76/Neoverse-N1
559	  errata 1188873 and 1418040.
560
561	  Affected Cortex-A76/Neoverse-N1 cores (r0p0 to r3p1) could
562	  cause register corruption when accessing the timer registers
563	  from AArch32 userspace.
564
565	  If unsure, say Y.
566
567config ARM64_WORKAROUND_SPECULATIVE_AT
568	bool
569
570config ARM64_ERRATUM_1165522
571	bool "Cortex-A76: 1165522: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
572	default y
573	select ARM64_WORKAROUND_SPECULATIVE_AT
574	help
575	  This option adds a workaround for ARM Cortex-A76 erratum 1165522.
576
577	  Affected Cortex-A76 cores (r0p0, r1p0, r2p0) could end-up with
578	  corrupted TLBs by speculating an AT instruction during a guest
579	  context switch.
580
581	  If unsure, say Y.
582
583config ARM64_ERRATUM_1319367
584	bool "Cortex-A57/A72: 1319537: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
585	default y
586	select ARM64_WORKAROUND_SPECULATIVE_AT
587	help
588	  This option adds work arounds for ARM Cortex-A57 erratum 1319537
589	  and A72 erratum 1319367
590
591	  Cortex-A57 and A72 cores could end-up with corrupted TLBs by
592	  speculating an AT instruction during a guest context switch.
593
594	  If unsure, say Y.
595
596config ARM64_ERRATUM_1530923
597	bool "Cortex-A55: 1530923: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
598	default y
599	select ARM64_WORKAROUND_SPECULATIVE_AT
600	help
601	  This option adds a workaround for ARM Cortex-A55 erratum 1530923.
602
603	  Affected Cortex-A55 cores (r0p0, r0p1, r1p0, r2p0) could end-up with
604	  corrupted TLBs by speculating an AT instruction during a guest
605	  context switch.
606
607	  If unsure, say Y.
608
609config ARM64_WORKAROUND_REPEAT_TLBI
610	bool
611
612config ARM64_ERRATUM_1286807
613	bool "Cortex-A76: Modification of the translation table for a virtual address might lead to read-after-read ordering violation"
614	default y
615	select ARM64_WORKAROUND_REPEAT_TLBI
616	help
617	  This option adds a workaround for ARM Cortex-A76 erratum 1286807.
618
619	  On the affected Cortex-A76 cores (r0p0 to r3p0), if a virtual
620	  address for a cacheable mapping of a location is being
621	  accessed by a core while another core is remapping the virtual
622	  address to a new physical page using the recommended
623	  break-before-make sequence, then under very rare circumstances
624	  TLBI+DSB completes before a read using the translation being
625	  invalidated has been observed by other observers. The
626	  workaround repeats the TLBI+DSB operation.
627
628config ARM64_ERRATUM_1463225
629	bool "Cortex-A76: Software Step might prevent interrupt recognition"
630	default y
631	help
632	  This option adds a workaround for Arm Cortex-A76 erratum 1463225.
633
634	  On the affected Cortex-A76 cores (r0p0 to r3p1), software stepping
635	  of a system call instruction (SVC) can prevent recognition of
636	  subsequent interrupts when software stepping is disabled in the
637	  exception handler of the system call and either kernel debugging
638	  is enabled or VHE is in use.
639
640	  Work around the erratum by triggering a dummy step exception
641	  when handling a system call from a task that is being stepped
642	  in a VHE configuration of the kernel.
643
644	  If unsure, say Y.
645
646config ARM64_ERRATUM_1542419
647	bool "Neoverse-N1: workaround mis-ordering of instruction fetches"
648	default y
649	help
650	  This option adds a workaround for ARM Neoverse-N1 erratum
651	  1542419.
652
653	  Affected Neoverse-N1 cores could execute a stale instruction when
654	  modified by another CPU. The workaround depends on a firmware
655	  counterpart.
656
657	  Workaround the issue by hiding the DIC feature from EL0. This
658	  forces user-space to perform cache maintenance.
659
660	  If unsure, say Y.
661
662config ARM64_ERRATUM_1508412
663	bool "Cortex-A77: 1508412: workaround deadlock on sequence of NC/Device load and store exclusive or PAR read"
664	default y
665	help
666	  This option adds a workaround for Arm Cortex-A77 erratum 1508412.
667
668	  Affected Cortex-A77 cores (r0p0, r1p0) could deadlock on a sequence
669	  of a store-exclusive or read of PAR_EL1 and a load with device or
670	  non-cacheable memory attributes. The workaround depends on a firmware
671	  counterpart.
672
673	  KVM guests must also have the workaround implemented or they can
674	  deadlock the system.
675
676	  Work around the issue by inserting DMB SY barriers around PAR_EL1
677	  register reads and warning KVM users. The DMB barrier is sufficient
678	  to prevent a speculative PAR_EL1 read.
679
680	  If unsure, say Y.
681
682config ARM64_ERRATUM_2457168
683	bool "Cortex-A510: 2457168: workaround for AMEVCNTR01 incrementing incorrectly"
684	depends on ARM64_AMU_EXTN
685	default y
686	help
687	  This option adds the workaround for ARM Cortex-A510 erratum 2457168.
688
689	  The AMU counter AMEVCNTR01 (constant counter) should increment at the same rate
690	  as the system counter. On affected Cortex-A510 cores AMEVCNTR01 increments
691	  incorrectly giving a significantly higher output value.
692
693	  Work around this problem by keeping the reference values of affected counters
694	  to 0 thus signaling an error case. This effect is the same to firmware disabling
695	  affected counters, in which case 0 will be returned when reading the disabled
696	  counters.
697
698	  If unsure, say Y.
699
700config CAVIUM_ERRATUM_22375
701	bool "Cavium erratum 22375, 24313"
702	default y
703	help
704	  Enable workaround for errata 22375 and 24313.
705
706	  This implements two gicv3-its errata workarounds for ThunderX. Both
707	  with a small impact affecting only ITS table allocation.
708
709	    erratum 22375: only alloc 8MB table size
710	    erratum 24313: ignore memory access type
711
712	  The fixes are in ITS initialization and basically ignore memory access
713	  type and table size provided by the TYPER and BASER registers.
714
715	  If unsure, say Y.
716
717config CAVIUM_ERRATUM_23144
718	bool "Cavium erratum 23144: ITS SYNC hang on dual socket system"
719	depends on NUMA
720	default y
721	help
722	  ITS SYNC command hang for cross node io and collections/cpu mapping.
723
724	  If unsure, say Y.
725
726config CAVIUM_ERRATUM_23154
727	bool "Cavium erratum 23154: Access to ICC_IAR1_EL1 is not sync'ed"
728	default y
729	help
730	  The gicv3 of ThunderX requires a modified version for
731	  reading the IAR status to ensure data synchronization
732	  (access to icc_iar1_el1 is not sync'ed before and after).
733
734	  If unsure, say Y.
735
736config CAVIUM_ERRATUM_27456
737	bool "Cavium erratum 27456: Broadcast TLBI instructions may cause icache corruption"
738	default y
739	help
740	  On ThunderX T88 pass 1.x through 2.1 parts, broadcast TLBI
741	  instructions may cause the icache to become corrupted if it
742	  contains data for a non-current ASID.  The fix is to
743	  invalidate the icache when changing the mm context.
744
745	  If unsure, say Y.
746
747config CAVIUM_ERRATUM_30115
748	bool "Cavium erratum 30115: Guest may disable interrupts in host"
749	default y
750	help
751	  On ThunderX T88 pass 1.x through 2.2, T81 pass 1.0 through
752	  1.2, and T83 Pass 1.0, KVM guest execution may disable
753	  interrupts in host. Trapping both GICv3 group-0 and group-1
754	  accesses sidesteps the issue.
755
756	  If unsure, say Y.
757
758config CAVIUM_TX2_ERRATUM_219
759	bool "Cavium ThunderX2 erratum 219: PRFM between TTBR change and ISB fails"
760	default y
761	help
762	  On Cavium ThunderX2, a load, store or prefetch instruction between a
763	  TTBR update and the corresponding context synchronizing operation can
764	  cause a spurious Data Abort to be delivered to any hardware thread in
765	  the CPU core.
766
767	  Work around the issue by avoiding the problematic code sequence and
768	  trapping KVM guest TTBRx_EL1 writes to EL2 when SMT is enabled. The
769	  trap handler performs the corresponding register access, skips the
770	  instruction and ensures context synchronization by virtue of the
771	  exception return.
772
773	  If unsure, say Y.
774
775config FUJITSU_ERRATUM_010001
776	bool "Fujitsu-A64FX erratum E#010001: Undefined fault may occur wrongly"
777	default y
778	help
779	  This option adds a workaround for Fujitsu-A64FX erratum E#010001.
780	  On some variants of the Fujitsu-A64FX cores ver(1.0, 1.1), memory
781	  accesses may cause undefined fault (Data abort, DFSC=0b111111).
782	  This fault occurs under a specific hardware condition when a
783	  load/store instruction performs an address translation using:
784	  case-1  TTBR0_EL1 with TCR_EL1.NFD0 == 1.
785	  case-2  TTBR0_EL2 with TCR_EL2.NFD0 == 1.
786	  case-3  TTBR1_EL1 with TCR_EL1.NFD1 == 1.
787	  case-4  TTBR1_EL2 with TCR_EL2.NFD1 == 1.
788
789	  The workaround is to ensure these bits are clear in TCR_ELx.
790	  The workaround only affects the Fujitsu-A64FX.
791
792	  If unsure, say Y.
793
794config HISILICON_ERRATUM_161600802
795	bool "Hip07 161600802: Erroneous redistributor VLPI base"
796	default y
797	help
798	  The HiSilicon Hip07 SoC uses the wrong redistributor base
799	  when issued ITS commands such as VMOVP and VMAPP, and requires
800	  a 128kB offset to be applied to the target address in this commands.
801
802	  If unsure, say Y.
803
804config QCOM_FALKOR_ERRATUM_1003
805	bool "Falkor E1003: Incorrect translation due to ASID change"
806	default y
807	help
808	  On Falkor v1, an incorrect ASID may be cached in the TLB when ASID
809	  and BADDR are changed together in TTBRx_EL1. Since we keep the ASID
810	  in TTBR1_EL1, this situation only occurs in the entry trampoline and
811	  then only for entries in the walk cache, since the leaf translation
812	  is unchanged. Work around the erratum by invalidating the walk cache
813	  entries for the trampoline before entering the kernel proper.
814
815config QCOM_FALKOR_ERRATUM_1009
816	bool "Falkor E1009: Prematurely complete a DSB after a TLBI"
817	default y
818	select ARM64_WORKAROUND_REPEAT_TLBI
819	help
820	  On Falkor v1, the CPU may prematurely complete a DSB following a
821	  TLBI xxIS invalidate maintenance operation. Repeat the TLBI operation
822	  one more time to fix the issue.
823
824	  If unsure, say Y.
825
826config QCOM_QDF2400_ERRATUM_0065
827	bool "QDF2400 E0065: Incorrect GITS_TYPER.ITT_Entry_size"
828	default y
829	help
830	  On Qualcomm Datacenter Technologies QDF2400 SoC, ITS hardware reports
831	  ITE size incorrectly. The GITS_TYPER.ITT_Entry_size field should have
832	  been indicated as 16Bytes (0xf), not 8Bytes (0x7).
833
834	  If unsure, say Y.
835
836config QCOM_FALKOR_ERRATUM_E1041
837	bool "Falkor E1041: Speculative instruction fetches might cause errant memory access"
838	default y
839	help
840	  Falkor CPU may speculatively fetch instructions from an improper
841	  memory location when MMU translation is changed from SCTLR_ELn[M]=1
842	  to SCTLR_ELn[M]=0. Prefix an ISB instruction to fix the problem.
843
844	  If unsure, say Y.
845
846config SOCIONEXT_SYNQUACER_PREITS
847	bool "Socionext Synquacer: Workaround for GICv3 pre-ITS"
848	default y
849	help
850	  Socionext Synquacer SoCs implement a separate h/w block to generate
851	  MSI doorbell writes with non-zero values for the device ID.
852
853	  If unsure, say Y.
854
855endmenu
856
857
858choice
859	prompt "Page size"
860	default ARM64_4K_PAGES
861	help
862	  Page size (translation granule) configuration.
863
864config ARM64_4K_PAGES
865	bool "4KB"
866	help
867	  This feature enables 4KB pages support.
868
869config ARM64_16K_PAGES
870	bool "16KB"
871	help
872	  The system will use 16KB pages support. AArch32 emulation
873	  requires applications compiled with 16K (or a multiple of 16K)
874	  aligned segments.
875
876config ARM64_64K_PAGES
877	bool "64KB"
878	help
879	  This feature enables 64KB pages support (4KB by default)
880	  allowing only two levels of page tables and faster TLB
881	  look-up. AArch32 emulation requires applications compiled
882	  with 64K aligned segments.
883
884endchoice
885
886choice
887	prompt "Virtual address space size"
888	default ARM64_VA_BITS_39 if ARM64_4K_PAGES
889	default ARM64_VA_BITS_47 if ARM64_16K_PAGES
890	default ARM64_VA_BITS_42 if ARM64_64K_PAGES
891	help
892	  Allows choosing one of multiple possible virtual address
893	  space sizes. The level of translation table is determined by
894	  a combination of page size and virtual address space size.
895
896config ARM64_VA_BITS_36
897	bool "36-bit" if EXPERT
898	depends on ARM64_16K_PAGES
899
900config ARM64_VA_BITS_39
901	bool "39-bit"
902	depends on ARM64_4K_PAGES
903
904config ARM64_VA_BITS_42
905	bool "42-bit"
906	depends on ARM64_64K_PAGES
907
908config ARM64_VA_BITS_47
909	bool "47-bit"
910	depends on ARM64_16K_PAGES
911
912config ARM64_VA_BITS_48
913	bool "48-bit"
914
915config ARM64_VA_BITS_52
916	bool "52-bit"
917	depends on ARM64_64K_PAGES && (ARM64_PAN || !ARM64_SW_TTBR0_PAN)
918	help
919	  Enable 52-bit virtual addressing for userspace when explicitly
920	  requested via a hint to mmap(). The kernel will also use 52-bit
921	  virtual addresses for its own mappings (provided HW support for
922	  this feature is available, otherwise it reverts to 48-bit).
923
924	  NOTE: Enabling 52-bit virtual addressing in conjunction with
925	  ARMv8.3 Pointer Authentication will result in the PAC being
926	  reduced from 7 bits to 3 bits, which may have a significant
927	  impact on its susceptibility to brute-force attacks.
928
929	  If unsure, select 48-bit virtual addressing instead.
930
931endchoice
932
933config ARM64_FORCE_52BIT
934	bool "Force 52-bit virtual addresses for userspace"
935	depends on ARM64_VA_BITS_52 && EXPERT
936	help
937	  For systems with 52-bit userspace VAs enabled, the kernel will attempt
938	  to maintain compatibility with older software by providing 48-bit VAs
939	  unless a hint is supplied to mmap.
940
941	  This configuration option disables the 48-bit compatibility logic, and
942	  forces all userspace addresses to be 52-bit on HW that supports it. One
943	  should only enable this configuration option for stress testing userspace
944	  memory management code. If unsure say N here.
945
946config ARM64_VA_BITS
947	int
948	default 36 if ARM64_VA_BITS_36
949	default 39 if ARM64_VA_BITS_39
950	default 42 if ARM64_VA_BITS_42
951	default 47 if ARM64_VA_BITS_47
952	default 48 if ARM64_VA_BITS_48
953	default 52 if ARM64_VA_BITS_52
954
955choice
956	prompt "Physical address space size"
957	default ARM64_PA_BITS_48
958	help
959	  Choose the maximum physical address range that the kernel will
960	  support.
961
962config ARM64_PA_BITS_48
963	bool "48-bit"
964
965config ARM64_PA_BITS_52
966	bool "52-bit (ARMv8.2)"
967	depends on ARM64_64K_PAGES
968	depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
969	help
970	  Enable support for a 52-bit physical address space, introduced as
971	  part of the ARMv8.2-LPA extension.
972
973	  With this enabled, the kernel will also continue to work on CPUs that
974	  do not support ARMv8.2-LPA, but with some added memory overhead (and
975	  minor performance overhead).
976
977endchoice
978
979config ARM64_PA_BITS
980	int
981	default 48 if ARM64_PA_BITS_48
982	default 52 if ARM64_PA_BITS_52
983
984choice
985	prompt "Endianness"
986	default CPU_LITTLE_ENDIAN
987	help
988	  Select the endianness of data accesses performed by the CPU. Userspace
989	  applications will need to be compiled and linked for the endianness
990	  that is selected here.
991
992config CPU_BIG_ENDIAN
993	bool "Build big-endian kernel"
994	depends on !LD_IS_LLD || LLD_VERSION >= 130000
995	help
996	  Say Y if you plan on running a kernel with a big-endian userspace.
997
998config CPU_LITTLE_ENDIAN
999	bool "Build little-endian kernel"
1000	help
1001	  Say Y if you plan on running a kernel with a little-endian userspace.
1002	  This is usually the case for distributions targeting arm64.
1003
1004endchoice
1005
1006config SCHED_MC
1007	bool "Multi-core scheduler support"
1008	help
1009	  Multi-core scheduler support improves the CPU scheduler's decision
1010	  making when dealing with multi-core CPU chips at a cost of slightly
1011	  increased overhead in some places. If unsure say N here.
1012
1013config SCHED_SMT
1014	bool "SMT scheduler support"
1015	help
1016	  Improves the CPU scheduler's decision making when dealing with
1017	  MultiThreading at a cost of slightly increased overhead in some
1018	  places. If unsure say N here.
1019
1020config NR_CPUS
1021	int "Maximum number of CPUs (2-4096)"
1022	range 2 4096
1023	default "256"
1024
1025config HOTPLUG_CPU
1026	bool "Support for hot-pluggable CPUs"
1027	select GENERIC_IRQ_MIGRATION
1028	help
1029	  Say Y here to experiment with turning CPUs off and on.  CPUs
1030	  can be controlled through /sys/devices/system/cpu.
1031
1032# Common NUMA Features
1033config NUMA
1034	bool "NUMA Memory Allocation and Scheduler Support"
1035	select ACPI_NUMA if ACPI
1036	select OF_NUMA
1037	help
1038	  Enable NUMA (Non-Uniform Memory Access) support.
1039
1040	  The kernel will try to allocate memory used by a CPU on the
1041	  local memory of the CPU and add some more
1042	  NUMA awareness to the kernel.
1043
1044config NODES_SHIFT
1045	int "Maximum NUMA Nodes (as a power of 2)"
1046	range 1 10
1047	default "4"
1048	depends on NEED_MULTIPLE_NODES
1049	help
1050	  Specify the maximum number of NUMA Nodes available on the target
1051	  system.  Increases memory reserved to accommodate various tables.
1052
1053config USE_PERCPU_NUMA_NODE_ID
1054	def_bool y
1055	depends on NUMA
1056
1057config HAVE_SETUP_PER_CPU_AREA
1058	def_bool y
1059	depends on NUMA
1060
1061config NEED_PER_CPU_EMBED_FIRST_CHUNK
1062	def_bool y
1063	depends on NUMA
1064
1065source "kernel/Kconfig.hz"
1066
1067config ARCH_SUPPORTS_DEBUG_PAGEALLOC
1068	def_bool y
1069
1070config ARCH_SPARSEMEM_ENABLE
1071	def_bool y
1072	select SPARSEMEM_VMEMMAP_ENABLE
1073
1074config ARCH_SPARSEMEM_DEFAULT
1075	def_bool ARCH_SPARSEMEM_ENABLE
1076
1077config ARCH_SELECT_MEMORY_MODEL
1078	def_bool ARCH_SPARSEMEM_ENABLE
1079
1080config ARCH_FLATMEM_ENABLE
1081	def_bool !NUMA
1082
1083config HAVE_ARCH_PFN_VALID
1084	def_bool y
1085
1086config HW_PERF_EVENTS
1087	def_bool y
1088	depends on ARM_PMU
1089
1090config SYS_SUPPORTS_HUGETLBFS
1091	def_bool y
1092
1093config ARCH_WANT_HUGE_PMD_SHARE
1094
1095config ARCH_HAS_CACHE_LINE_SIZE
1096	def_bool y
1097
1098config ARCH_ENABLE_SPLIT_PMD_PTLOCK
1099	def_bool y if PGTABLE_LEVELS > 2
1100
1101# Supported by clang >= 7.0
1102config CC_HAVE_SHADOW_CALL_STACK
1103	def_bool $(cc-option, -fsanitize=shadow-call-stack -ffixed-x18)
1104
1105config PARAVIRT
1106	bool "Enable paravirtualization code"
1107	help
1108	  This changes the kernel so it can modify itself when it is run
1109	  under a hypervisor, potentially improving performance significantly
1110	  over full virtualization.
1111
1112config PARAVIRT_TIME_ACCOUNTING
1113	bool "Paravirtual steal time accounting"
1114	select PARAVIRT
1115	help
1116	  Select this option to enable fine granularity task steal time
1117	  accounting. Time spent executing other tasks in parallel with
1118	  the current vCPU is discounted from the vCPU power. To account for
1119	  that, there can be a small performance impact.
1120
1121	  If in doubt, say N here.
1122
1123config KEXEC
1124	depends on PM_SLEEP_SMP
1125	select KEXEC_CORE
1126	bool "kexec system call"
1127	help
1128	  kexec is a system call that implements the ability to shutdown your
1129	  current kernel, and to start another kernel.  It is like a reboot
1130	  but it is independent of the system firmware.   And like a reboot
1131	  you can start any kernel with it, not just Linux.
1132
1133config KEXEC_FILE
1134	bool "kexec file based system call"
1135	select KEXEC_CORE
1136	help
1137	  This is new version of kexec system call. This system call is
1138	  file based and takes file descriptors as system call argument
1139	  for kernel and initramfs as opposed to list of segments as
1140	  accepted by previous system call.
1141
1142config KEXEC_SIG
1143	bool "Verify kernel signature during kexec_file_load() syscall"
1144	depends on KEXEC_FILE
1145	help
1146	  Select this option to verify a signature with loaded kernel
1147	  image. If configured, any attempt of loading a image without
1148	  valid signature will fail.
1149
1150	  In addition to that option, you need to enable signature
1151	  verification for the corresponding kernel image type being
1152	  loaded in order for this to work.
1153
1154config KEXEC_IMAGE_VERIFY_SIG
1155	bool "Enable Image signature verification support"
1156	default y
1157	depends on KEXEC_SIG
1158	depends on EFI && SIGNED_PE_FILE_VERIFICATION
1159	help
1160	  Enable Image signature verification support.
1161
1162comment "Support for PE file signature verification disabled"
1163	depends on KEXEC_SIG
1164	depends on !EFI || !SIGNED_PE_FILE_VERIFICATION
1165
1166config CRASH_DUMP
1167	bool "Build kdump crash kernel"
1168	help
1169	  Generate crash dump after being started by kexec. This should
1170	  be normally only set in special crash dump kernels which are
1171	  loaded in the main kernel with kexec-tools into a specially
1172	  reserved region and then later executed after a crash by
1173	  kdump/kexec.
1174
1175	  For more details see Documentation/admin-guide/kdump/kdump.rst
1176
1177config XEN_DOM0
1178	def_bool y
1179	depends on XEN
1180
1181config XEN
1182	bool "Xen guest support on ARM64"
1183	depends on ARM64 && OF
1184	select SWIOTLB_XEN
1185	select PARAVIRT
1186	help
1187	  Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64.
1188
1189config FORCE_MAX_ZONEORDER
1190	int
1191	default "14" if (ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE)
1192	default "12" if (ARM64_16K_PAGES && TRANSPARENT_HUGEPAGE)
1193	default "11"
1194	help
1195	  The kernel memory allocator divides physically contiguous memory
1196	  blocks into "zones", where each zone is a power of two number of
1197	  pages.  This option selects the largest power of two that the kernel
1198	  keeps in the memory allocator.  If you need to allocate very large
1199	  blocks of physically contiguous memory, then you may need to
1200	  increase this value.
1201
1202	  This config option is actually maximum order plus one. For example,
1203	  a value of 11 means that the largest free memory block is 2^10 pages.
1204
1205	  We make sure that we can allocate upto a HugePage size for each configuration.
1206	  Hence we have :
1207		MAX_ORDER = (PMD_SHIFT - PAGE_SHIFT) + 1 => PAGE_SHIFT - 2
1208
1209	  However for 4K, we choose a higher default value, 11 as opposed to 10, giving us
1210	  4M allocations matching the default size used by generic code.
1211
1212config UNMAP_KERNEL_AT_EL0
1213	bool "Unmap kernel when running in userspace (aka \"KAISER\")" if EXPERT
1214	default y
1215	help
1216	  Speculation attacks against some high-performance processors can
1217	  be used to bypass MMU permission checks and leak kernel data to
1218	  userspace. This can be defended against by unmapping the kernel
1219	  when running in userspace, mapping it back in on exception entry
1220	  via a trampoline page in the vector table.
1221
1222	  If unsure, say Y.
1223
1224config MITIGATE_SPECTRE_BRANCH_HISTORY
1225	bool "Mitigate Spectre style attacks against branch history" if EXPERT
1226	default y
1227	help
1228	  Speculation attacks against some high-performance processors can
1229	  make use of branch history to influence future speculation.
1230	  When taking an exception from user-space, a sequence of branches
1231	  or a firmware call overwrites the branch history.
1232
1233config RODATA_FULL_DEFAULT_ENABLED
1234	bool "Apply r/o permissions of VM areas also to their linear aliases"
1235	default y
1236	help
1237	  Apply read-only attributes of VM areas to the linear alias of
1238	  the backing pages as well. This prevents code or read-only data
1239	  from being modified (inadvertently or intentionally) via another
1240	  mapping of the same memory page. This additional enhancement can
1241	  be turned off at runtime by passing rodata=[off|on] (and turned on
1242	  with rodata=full if this option is set to 'n')
1243
1244	  This requires the linear region to be mapped down to pages,
1245	  which may adversely affect performance in some cases.
1246
1247config ARM64_SW_TTBR0_PAN
1248	bool "Emulate Privileged Access Never using TTBR0_EL1 switching"
1249	help
1250	  Enabling this option prevents the kernel from accessing
1251	  user-space memory directly by pointing TTBR0_EL1 to a reserved
1252	  zeroed area and reserved ASID. The user access routines
1253	  restore the valid TTBR0_EL1 temporarily.
1254
1255config ARM64_TAGGED_ADDR_ABI
1256	bool "Enable the tagged user addresses syscall ABI"
1257	default y
1258	help
1259	  When this option is enabled, user applications can opt in to a
1260	  relaxed ABI via prctl() allowing tagged addresses to be passed
1261	  to system calls as pointer arguments. For details, see
1262	  Documentation/arm64/tagged-address-abi.rst.
1263
1264menuconfig COMPAT
1265	bool "Kernel support for 32-bit EL0"
1266	depends on ARM64_4K_PAGES || EXPERT
1267	select COMPAT_BINFMT_ELF if BINFMT_ELF
1268	select HAVE_UID16
1269	select OLD_SIGSUSPEND3
1270	select COMPAT_OLD_SIGACTION
1271	help
1272	  This option enables support for a 32-bit EL0 running under a 64-bit
1273	  kernel at EL1. AArch32-specific components such as system calls,
1274	  the user helper functions, VFP support and the ptrace interface are
1275	  handled appropriately by the kernel.
1276
1277	  If you use a page size other than 4KB (i.e, 16KB or 64KB), please be aware
1278	  that you will only be able to execute AArch32 binaries that were compiled
1279	  with page size aligned segments.
1280
1281	  If you want to execute 32-bit userspace applications, say Y.
1282
1283if COMPAT
1284
1285config KUSER_HELPERS
1286	bool "Enable kuser helpers page for 32-bit applications"
1287	default y
1288	help
1289	  Warning: disabling this option may break 32-bit user programs.
1290
1291	  Provide kuser helpers to compat tasks. The kernel provides
1292	  helper code to userspace in read only form at a fixed location
1293	  to allow userspace to be independent of the CPU type fitted to
1294	  the system. This permits binaries to be run on ARMv4 through
1295	  to ARMv8 without modification.
1296
1297	  See Documentation/arm/kernel_user_helpers.rst for details.
1298
1299	  However, the fixed address nature of these helpers can be used
1300	  by ROP (return orientated programming) authors when creating
1301	  exploits.
1302
1303	  If all of the binaries and libraries which run on your platform
1304	  are built specifically for your platform, and make no use of
1305	  these helpers, then you can turn this option off to hinder
1306	  such exploits. However, in that case, if a binary or library
1307	  relying on those helpers is run, it will not function correctly.
1308
1309	  Say N here only if you are absolutely certain that you do not
1310	  need these helpers; otherwise, the safe option is to say Y.
1311
1312config COMPAT_VDSO
1313	bool "Enable vDSO for 32-bit applications"
1314	depends on !CPU_BIG_ENDIAN
1315	depends on (CC_IS_CLANG && LD_IS_LLD) || "$(CROSS_COMPILE_COMPAT)" != ""
1316	select GENERIC_COMPAT_VDSO
1317	default y
1318	help
1319	  Place in the process address space of 32-bit applications an
1320	  ELF shared object providing fast implementations of gettimeofday
1321	  and clock_gettime.
1322
1323	  You must have a 32-bit build of glibc 2.22 or later for programs
1324	  to seamlessly take advantage of this.
1325
1326config THUMB2_COMPAT_VDSO
1327	bool "Compile the 32-bit vDSO for Thumb-2 mode" if EXPERT
1328	depends on COMPAT_VDSO
1329	default y
1330	help
1331	  Compile the compat vDSO with '-mthumb -fomit-frame-pointer' if y,
1332	  otherwise with '-marm'.
1333
1334menuconfig ARMV8_DEPRECATED
1335	bool "Emulate deprecated/obsolete ARMv8 instructions"
1336	depends on SYSCTL
1337	help
1338	  Legacy software support may require certain instructions
1339	  that have been deprecated or obsoleted in the architecture.
1340
1341	  Enable this config to enable selective emulation of these
1342	  features.
1343
1344	  If unsure, say Y
1345
1346if ARMV8_DEPRECATED
1347
1348config SWP_EMULATION
1349	bool "Emulate SWP/SWPB instructions"
1350	help
1351	  ARMv8 obsoletes the use of A32 SWP/SWPB instructions such that
1352	  they are always undefined. Say Y here to enable software
1353	  emulation of these instructions for userspace using LDXR/STXR.
1354	  This feature can be controlled at runtime with the abi.swp
1355	  sysctl which is disabled by default.
1356
1357	  In some older versions of glibc [<=2.8] SWP is used during futex
1358	  trylock() operations with the assumption that the code will not
1359	  be preempted. This invalid assumption may be more likely to fail
1360	  with SWP emulation enabled, leading to deadlock of the user
1361	  application.
1362
1363	  NOTE: when accessing uncached shared regions, LDXR/STXR rely
1364	  on an external transaction monitoring block called a global
1365	  monitor to maintain update atomicity. If your system does not
1366	  implement a global monitor, this option can cause programs that
1367	  perform SWP operations to uncached memory to deadlock.
1368
1369	  If unsure, say Y
1370
1371config CP15_BARRIER_EMULATION
1372	bool "Emulate CP15 Barrier instructions"
1373	help
1374	  The CP15 barrier instructions - CP15ISB, CP15DSB, and
1375	  CP15DMB - are deprecated in ARMv8 (and ARMv7). It is
1376	  strongly recommended to use the ISB, DSB, and DMB
1377	  instructions instead.
1378
1379	  Say Y here to enable software emulation of these
1380	  instructions for AArch32 userspace code. When this option is
1381	  enabled, CP15 barrier usage is traced which can help
1382	  identify software that needs updating. This feature can be
1383	  controlled at runtime with the abi.cp15_barrier sysctl.
1384
1385	  If unsure, say Y
1386
1387config SETEND_EMULATION
1388	bool "Emulate SETEND instruction"
1389	help
1390	  The SETEND instruction alters the data-endianness of the
1391	  AArch32 EL0, and is deprecated in ARMv8.
1392
1393	  Say Y here to enable software emulation of the instruction
1394	  for AArch32 userspace code. This feature can be controlled
1395	  at runtime with the abi.setend sysctl.
1396
1397	  Note: All the cpus on the system must have mixed endian support at EL0
1398	  for this feature to be enabled. If a new CPU - which doesn't support mixed
1399	  endian - is hotplugged in after this feature has been enabled, there could
1400	  be unexpected results in the applications.
1401
1402	  If unsure, say Y
1403endif
1404
1405endif
1406
1407menu "ARMv8.1 architectural features"
1408
1409config ARM64_HW_AFDBM
1410	bool "Support for hardware updates of the Access and Dirty page flags"
1411	default y
1412	help
1413	  The ARMv8.1 architecture extensions introduce support for
1414	  hardware updates of the access and dirty information in page
1415	  table entries. When enabled in TCR_EL1 (HA and HD bits) on
1416	  capable processors, accesses to pages with PTE_AF cleared will
1417	  set this bit instead of raising an access flag fault.
1418	  Similarly, writes to read-only pages with the DBM bit set will
1419	  clear the read-only bit (AP[2]) instead of raising a
1420	  permission fault.
1421
1422	  Kernels built with this configuration option enabled continue
1423	  to work on pre-ARMv8.1 hardware and the performance impact is
1424	  minimal. If unsure, say Y.
1425
1426config ARM64_PAN
1427	bool "Enable support for Privileged Access Never (PAN)"
1428	default y
1429	help
1430	 Privileged Access Never (PAN; part of the ARMv8.1 Extensions)
1431	 prevents the kernel or hypervisor from accessing user-space (EL0)
1432	 memory directly.
1433
1434	 Choosing this option will cause any unprotected (not using
1435	 copy_to_user et al) memory access to fail with a permission fault.
1436
1437	 The feature is detected at runtime, and will remain as a 'nop'
1438	 instruction if the cpu does not implement the feature.
1439
1440config AS_HAS_LSE_ATOMICS
1441	def_bool $(as-instr,.arch_extension lse)
1442
1443config ARM64_LSE_ATOMICS
1444	bool
1445	default ARM64_USE_LSE_ATOMICS
1446	depends on AS_HAS_LSE_ATOMICS
1447
1448config ARM64_USE_LSE_ATOMICS
1449	bool "Atomic instructions"
1450	depends on JUMP_LABEL
1451	default y
1452	help
1453	  As part of the Large System Extensions, ARMv8.1 introduces new
1454	  atomic instructions that are designed specifically to scale in
1455	  very large systems.
1456
1457	  Say Y here to make use of these instructions for the in-kernel
1458	  atomic routines. This incurs a small overhead on CPUs that do
1459	  not support these instructions and requires the kernel to be
1460	  built with binutils >= 2.25 in order for the new instructions
1461	  to be used.
1462
1463config ARM64_VHE
1464	bool "Enable support for Virtualization Host Extensions (VHE)"
1465	default y
1466	help
1467	  Virtualization Host Extensions (VHE) allow the kernel to run
1468	  directly at EL2 (instead of EL1) on processors that support
1469	  it. This leads to better performance for KVM, as they reduce
1470	  the cost of the world switch.
1471
1472	  Selecting this option allows the VHE feature to be detected
1473	  at runtime, and does not affect processors that do not
1474	  implement this feature.
1475
1476endmenu
1477
1478menu "ARMv8.2 architectural features"
1479
1480config ARM64_UAO
1481	bool "Enable support for User Access Override (UAO)"
1482	default y
1483	help
1484	  User Access Override (UAO; part of the ARMv8.2 Extensions)
1485	  causes the 'unprivileged' variant of the load/store instructions to
1486	  be overridden to be privileged.
1487
1488	  This option changes get_user() and friends to use the 'unprivileged'
1489	  variant of the load/store instructions. This ensures that user-space
1490	  really did have access to the supplied memory. When addr_limit is
1491	  set to kernel memory the UAO bit will be set, allowing privileged
1492	  access to kernel memory.
1493
1494	  Choosing this option will cause copy_to_user() et al to use user-space
1495	  memory permissions.
1496
1497	  The feature is detected at runtime, the kernel will use the
1498	  regular load/store instructions if the cpu does not implement the
1499	  feature.
1500
1501config ARM64_PMEM
1502	bool "Enable support for persistent memory"
1503	select ARCH_HAS_PMEM_API
1504	select ARCH_HAS_UACCESS_FLUSHCACHE
1505	help
1506	  Say Y to enable support for the persistent memory API based on the
1507	  ARMv8.2 DCPoP feature.
1508
1509	  The feature is detected at runtime, and the kernel will use DC CVAC
1510	  operations if DC CVAP is not supported (following the behaviour of
1511	  DC CVAP itself if the system does not define a point of persistence).
1512
1513config ARM64_RAS_EXTN
1514	bool "Enable support for RAS CPU Extensions"
1515	default y
1516	help
1517	  CPUs that support the Reliability, Availability and Serviceability
1518	  (RAS) Extensions, part of ARMv8.2 are able to track faults and
1519	  errors, classify them and report them to software.
1520
1521	  On CPUs with these extensions system software can use additional
1522	  barriers to determine if faults are pending and read the
1523	  classification from a new set of registers.
1524
1525	  Selecting this feature will allow the kernel to use these barriers
1526	  and access the new registers if the system supports the extension.
1527	  Platform RAS features may additionally depend on firmware support.
1528
1529config ARM64_CNP
1530	bool "Enable support for Common Not Private (CNP) translations"
1531	default y
1532	depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
1533	help
1534	  Common Not Private (CNP) allows translation table entries to
1535	  be shared between different PEs in the same inner shareable
1536	  domain, so the hardware can use this fact to optimise the
1537	  caching of such entries in the TLB.
1538
1539	  Selecting this option allows the CNP feature to be detected
1540	  at runtime, and does not affect PEs that do not implement
1541	  this feature.
1542
1543endmenu
1544
1545menu "ARMv8.3 architectural features"
1546
1547config ARM64_PTR_AUTH
1548	bool "Enable support for pointer authentication"
1549	default y
1550	depends on (CC_HAS_SIGN_RETURN_ADDRESS || CC_HAS_BRANCH_PROT_PAC_RET) && AS_HAS_PAC
1551	# Modern compilers insert a .note.gnu.property section note for PAC
1552	# which is only understood by binutils starting with version 2.33.1.
1553	depends on LD_IS_LLD || LD_VERSION >= 233010000 || (CC_IS_GCC && GCC_VERSION < 90100)
1554	depends on !CC_IS_CLANG || AS_HAS_CFI_NEGATE_RA_STATE
1555	depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_REGS)
1556	help
1557	  Pointer authentication (part of the ARMv8.3 Extensions) provides
1558	  instructions for signing and authenticating pointers against secret
1559	  keys, which can be used to mitigate Return Oriented Programming (ROP)
1560	  and other attacks.
1561
1562	  This option enables these instructions at EL0 (i.e. for userspace).
1563	  Choosing this option will cause the kernel to initialise secret keys
1564	  for each process at exec() time, with these keys being
1565	  context-switched along with the process.
1566
1567	  If the compiler supports the -mbranch-protection or
1568	  -msign-return-address flag (e.g. GCC 7 or later), then this option
1569	  will also cause the kernel itself to be compiled with return address
1570	  protection. In this case, and if the target hardware is known to
1571	  support pointer authentication, then CONFIG_STACKPROTECTOR can be
1572	  disabled with minimal loss of protection.
1573
1574	  The feature is detected at runtime. If the feature is not present in
1575	  hardware it will not be advertised to userspace/KVM guest nor will it
1576	  be enabled.
1577
1578	  If the feature is present on the boot CPU but not on a late CPU, then
1579	  the late CPU will be parked. Also, if the boot CPU does not have
1580	  address auth and the late CPU has then the late CPU will still boot
1581	  but with the feature disabled. On such a system, this option should
1582	  not be selected.
1583
1584	  This feature works with FUNCTION_GRAPH_TRACER option only if
1585	  DYNAMIC_FTRACE_WITH_REGS is enabled.
1586
1587config CC_HAS_BRANCH_PROT_PAC_RET
1588	# GCC 9 or later, clang 8 or later
1589	def_bool $(cc-option,-mbranch-protection=pac-ret+leaf)
1590
1591config CC_HAS_SIGN_RETURN_ADDRESS
1592	# GCC 7, 8
1593	def_bool $(cc-option,-msign-return-address=all)
1594
1595config AS_HAS_PAC
1596	def_bool $(cc-option,-Wa$(comma)-march=armv8.3-a)
1597
1598config AS_HAS_CFI_NEGATE_RA_STATE
1599	def_bool $(as-instr,.cfi_startproc\n.cfi_negate_ra_state\n.cfi_endproc\n)
1600
1601endmenu
1602
1603menu "ARMv8.4 architectural features"
1604
1605config ARM64_AMU_EXTN
1606	bool "Enable support for the Activity Monitors Unit CPU extension"
1607	default y
1608	help
1609	  The activity monitors extension is an optional extension introduced
1610	  by the ARMv8.4 CPU architecture. This enables support for version 1
1611	  of the activity monitors architecture, AMUv1.
1612
1613	  To enable the use of this extension on CPUs that implement it, say Y.
1614
1615	  Note that for architectural reasons, firmware _must_ implement AMU
1616	  support when running on CPUs that present the activity monitors
1617	  extension. The required support is present in:
1618	    * Version 1.5 and later of the ARM Trusted Firmware
1619
1620	  For kernels that have this configuration enabled but boot with broken
1621	  firmware, you may need to say N here until the firmware is fixed.
1622	  Otherwise you may experience firmware panics or lockups when
1623	  accessing the counter registers. Even if you are not observing these
1624	  symptoms, the values returned by the register reads might not
1625	  correctly reflect reality. Most commonly, the value read will be 0,
1626	  indicating that the counter is not enabled.
1627
1628config AS_HAS_ARMV8_4
1629	def_bool $(cc-option,-Wa$(comma)-march=armv8.4-a)
1630
1631config ARM64_TLB_RANGE
1632	bool "Enable support for tlbi range feature"
1633	default y
1634	depends on AS_HAS_ARMV8_4
1635	help
1636	  ARMv8.4-TLBI provides TLBI invalidation instruction that apply to a
1637	  range of input addresses.
1638
1639	  The feature introduces new assembly instructions, and they were
1640	  support when binutils >= 2.30.
1641
1642endmenu
1643
1644menu "ARMv8.5 architectural features"
1645
1646config ARM64_BTI
1647	bool "Branch Target Identification support"
1648	default y
1649	help
1650	  Branch Target Identification (part of the ARMv8.5 Extensions)
1651	  provides a mechanism to limit the set of locations to which computed
1652	  branch instructions such as BR or BLR can jump.
1653
1654	  To make use of BTI on CPUs that support it, say Y.
1655
1656	  BTI is intended to provide complementary protection to other control
1657	  flow integrity protection mechanisms, such as the Pointer
1658	  authentication mechanism provided as part of the ARMv8.3 Extensions.
1659	  For this reason, it does not make sense to enable this option without
1660	  also enabling support for pointer authentication.  Thus, when
1661	  enabling this option you should also select ARM64_PTR_AUTH=y.
1662
1663	  Userspace binaries must also be specifically compiled to make use of
1664	  this mechanism.  If you say N here or the hardware does not support
1665	  BTI, such binaries can still run, but you get no additional
1666	  enforcement of branch destinations.
1667
1668config ARM64_BTI_KERNEL
1669	bool "Use Branch Target Identification for kernel"
1670	default y
1671	depends on ARM64_BTI
1672	depends on ARM64_PTR_AUTH
1673	depends on CC_HAS_BRANCH_PROT_PAC_RET_BTI
1674	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94697
1675	depends on !CC_IS_GCC || GCC_VERSION >= 100100
1676	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106671
1677	depends on !CC_IS_GCC
1678	# https://github.com/llvm/llvm-project/commit/a88c722e687e6780dcd6a58718350dc76fcc4cc9
1679	depends on !CC_IS_CLANG || CLANG_VERSION >= 120000
1680	depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_REGS)
1681	help
1682	  Build the kernel with Branch Target Identification annotations
1683	  and enable enforcement of this for kernel code. When this option
1684	  is enabled and the system supports BTI all kernel code including
1685	  modular code must have BTI enabled.
1686
1687config CC_HAS_BRANCH_PROT_PAC_RET_BTI
1688	# GCC 9 or later, clang 8 or later
1689	def_bool $(cc-option,-mbranch-protection=pac-ret+leaf+bti)
1690
1691config ARM64_E0PD
1692	bool "Enable support for E0PD"
1693	default y
1694	help
1695	  E0PD (part of the ARMv8.5 extensions) allows us to ensure
1696	  that EL0 accesses made via TTBR1 always fault in constant time,
1697	  providing similar benefits to KASLR as those provided by KPTI, but
1698	  with lower overhead and without disrupting legitimate access to
1699	  kernel memory such as SPE.
1700
1701	  This option enables E0PD for TTBR1 where available.
1702
1703config ARCH_RANDOM
1704	bool "Enable support for random number generation"
1705	default y
1706	help
1707	  Random number generation (part of the ARMv8.5 Extensions)
1708	  provides a high bandwidth, cryptographically secure
1709	  hardware random number generator.
1710
1711config ARM64_AS_HAS_MTE
1712	# Initial support for MTE went in binutils 2.32.0, checked with
1713	# ".arch armv8.5-a+memtag" below. However, this was incomplete
1714	# as a late addition to the final architecture spec (LDGM/STGM)
1715	# is only supported in the newer 2.32.x and 2.33 binutils
1716	# versions, hence the extra "stgm" instruction check below.
1717	def_bool $(as-instr,.arch armv8.5-a+memtag\nstgm xzr$(comma)[x0])
1718
1719config ARM64_MTE
1720	bool "Memory Tagging Extension support"
1721	default y
1722	depends on ARM64_AS_HAS_MTE && ARM64_TAGGED_ADDR_ABI
1723	depends on AS_HAS_LSE_ATOMICS
1724	select ARCH_USES_HIGH_VMA_FLAGS
1725	help
1726	  Memory Tagging (part of the ARMv8.5 Extensions) provides
1727	  architectural support for run-time, always-on detection of
1728	  various classes of memory error to aid with software debugging
1729	  to eliminate vulnerabilities arising from memory-unsafe
1730	  languages.
1731
1732	  This option enables the support for the Memory Tagging
1733	  Extension at EL0 (i.e. for userspace).
1734
1735	  Selecting this option allows the feature to be detected at
1736	  runtime. Any secondary CPU not implementing this feature will
1737	  not be allowed a late bring-up.
1738
1739	  Userspace binaries that want to use this feature must
1740	  explicitly opt in. The mechanism for the userspace is
1741	  described in:
1742
1743	  Documentation/arm64/memory-tagging-extension.rst.
1744
1745endmenu
1746
1747config ARM64_SVE
1748	bool "ARM Scalable Vector Extension support"
1749	default y
1750	depends on !KVM || ARM64_VHE
1751	help
1752	  The Scalable Vector Extension (SVE) is an extension to the AArch64
1753	  execution state which complements and extends the SIMD functionality
1754	  of the base architecture to support much larger vectors and to enable
1755	  additional vectorisation opportunities.
1756
1757	  To enable use of this extension on CPUs that implement it, say Y.
1758
1759	  On CPUs that support the SVE2 extensions, this option will enable
1760	  those too.
1761
1762	  Note that for architectural reasons, firmware _must_ implement SVE
1763	  support when running on SVE capable hardware.  The required support
1764	  is present in:
1765
1766	    * version 1.5 and later of the ARM Trusted Firmware
1767	    * the AArch64 boot wrapper since commit 5e1261e08abf
1768	      ("bootwrapper: SVE: Enable SVE for EL2 and below").
1769
1770	  For other firmware implementations, consult the firmware documentation
1771	  or vendor.
1772
1773	  If you need the kernel to boot on SVE-capable hardware with broken
1774	  firmware, you may need to say N here until you get your firmware
1775	  fixed.  Otherwise, you may experience firmware panics or lockups when
1776	  booting the kernel.  If unsure and you are not observing these
1777	  symptoms, you should assume that it is safe to say Y.
1778
1779	  CPUs that support SVE are architecturally required to support the
1780	  Virtualization Host Extensions (VHE), so the kernel makes no
1781	  provision for supporting SVE alongside KVM without VHE enabled.
1782	  Thus, you will need to enable CONFIG_ARM64_VHE if you want to support
1783	  KVM in the same kernel image.
1784
1785config ARM64_MODULE_PLTS
1786	bool "Use PLTs to allow module memory to spill over into vmalloc area"
1787	depends on MODULES
1788	select HAVE_MOD_ARCH_SPECIFIC
1789	help
1790	  Allocate PLTs when loading modules so that jumps and calls whose
1791	  targets are too far away for their relative offsets to be encoded
1792	  in the instructions themselves can be bounced via veneers in the
1793	  module's PLT. This allows modules to be allocated in the generic
1794	  vmalloc area after the dedicated module memory area has been
1795	  exhausted.
1796
1797	  When running with address space randomization (KASLR), the module
1798	  region itself may be too far away for ordinary relative jumps and
1799	  calls, and so in that case, module PLTs are required and cannot be
1800	  disabled.
1801
1802	  Specific errata workaround(s) might also force module PLTs to be
1803	  enabled (ARM64_ERRATUM_843419).
1804
1805config ARM64_PSEUDO_NMI
1806	bool "Support for NMI-like interrupts"
1807	select ARM_GIC_V3
1808	help
1809	  Adds support for mimicking Non-Maskable Interrupts through the use of
1810	  GIC interrupt priority. This support requires version 3 or later of
1811	  ARM GIC.
1812
1813	  This high priority configuration for interrupts needs to be
1814	  explicitly enabled by setting the kernel parameter
1815	  "irqchip.gicv3_pseudo_nmi" to 1.
1816
1817	  If unsure, say N
1818
1819if ARM64_PSEUDO_NMI
1820config ARM64_DEBUG_PRIORITY_MASKING
1821	bool "Debug interrupt priority masking"
1822	help
1823	  This adds runtime checks to functions enabling/disabling
1824	  interrupts when using priority masking. The additional checks verify
1825	  the validity of ICC_PMR_EL1 when calling concerned functions.
1826
1827	  If unsure, say N
1828endif
1829
1830config RELOCATABLE
1831	bool "Build a relocatable kernel image" if EXPERT
1832	select ARCH_HAS_RELR
1833	default y
1834	help
1835	  This builds the kernel as a Position Independent Executable (PIE),
1836	  which retains all relocation metadata required to relocate the
1837	  kernel binary at runtime to a different virtual address than the
1838	  address it was linked at.
1839	  Since AArch64 uses the RELA relocation format, this requires a
1840	  relocation pass at runtime even if the kernel is loaded at the
1841	  same address it was linked at.
1842
1843config RANDOMIZE_BASE
1844	bool "Randomize the address of the kernel image"
1845	select ARM64_MODULE_PLTS if MODULES
1846	select RELOCATABLE
1847	help
1848	  Randomizes the virtual address at which the kernel image is
1849	  loaded, as a security feature that deters exploit attempts
1850	  relying on knowledge of the location of kernel internals.
1851
1852	  It is the bootloader's job to provide entropy, by passing a
1853	  random u64 value in /chosen/kaslr-seed at kernel entry.
1854
1855	  When booting via the UEFI stub, it will invoke the firmware's
1856	  EFI_RNG_PROTOCOL implementation (if available) to supply entropy
1857	  to the kernel proper. In addition, it will randomise the physical
1858	  location of the kernel Image as well.
1859
1860	  If unsure, say N.
1861
1862config RANDOMIZE_MODULE_REGION_FULL
1863	bool "Randomize the module region over a 4 GB range"
1864	depends on RANDOMIZE_BASE
1865	default y
1866	help
1867	  Randomizes the location of the module region inside a 4 GB window
1868	  covering the core kernel. This way, it is less likely for modules
1869	  to leak information about the location of core kernel data structures
1870	  but it does imply that function calls between modules and the core
1871	  kernel will need to be resolved via veneers in the module PLT.
1872
1873	  When this option is not set, the module region will be randomized over
1874	  a limited range that contains the [_stext, _etext] interval of the
1875	  core kernel, so branch relocations are always in range.
1876
1877config CC_HAVE_STACKPROTECTOR_SYSREG
1878	def_bool $(cc-option,-mstack-protector-guard=sysreg -mstack-protector-guard-reg=sp_el0 -mstack-protector-guard-offset=0)
1879
1880config STACKPROTECTOR_PER_TASK
1881	def_bool y
1882	depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_SYSREG
1883
1884endmenu
1885
1886menu "Boot options"
1887
1888config ARM64_ACPI_PARKING_PROTOCOL
1889	bool "Enable support for the ARM64 ACPI parking protocol"
1890	depends on ACPI
1891	help
1892	  Enable support for the ARM64 ACPI parking protocol. If disabled
1893	  the kernel will not allow booting through the ARM64 ACPI parking
1894	  protocol even if the corresponding data is present in the ACPI
1895	  MADT table.
1896
1897config CMDLINE
1898	string "Default kernel command string"
1899	default ""
1900	help
1901	  Provide a set of default command-line options at build time by
1902	  entering them here. As a minimum, you should specify the the
1903	  root device (e.g. root=/dev/nfs).
1904
1905config CMDLINE_FORCE
1906	bool "Always use the default kernel command string"
1907	depends on CMDLINE != ""
1908	help
1909	  Always use the default kernel command string, even if the boot
1910	  loader passes other arguments to the kernel.
1911	  This is useful if you cannot or don't want to change the
1912	  command-line options your boot loader passes to the kernel.
1913
1914config EFI_STUB
1915	bool
1916
1917config EFI
1918	bool "UEFI runtime support"
1919	depends on OF && !CPU_BIG_ENDIAN
1920	depends on KERNEL_MODE_NEON
1921	select ARCH_SUPPORTS_ACPI
1922	select LIBFDT
1923	select UCS2_STRING
1924	select EFI_PARAMS_FROM_FDT
1925	select EFI_RUNTIME_WRAPPERS
1926	select EFI_STUB
1927	select EFI_GENERIC_STUB
1928	default y
1929	help
1930	  This option provides support for runtime services provided
1931	  by UEFI firmware (such as non-volatile variables, realtime
1932          clock, and platform reset). A UEFI stub is also provided to
1933	  allow the kernel to be booted as an EFI application. This
1934	  is only useful on systems that have UEFI firmware.
1935
1936config DMI
1937	bool "Enable support for SMBIOS (DMI) tables"
1938	depends on EFI
1939	default y
1940	help
1941	  This enables SMBIOS/DMI feature for systems.
1942
1943	  This option is only useful on systems that have UEFI firmware.
1944	  However, even with this option, the resultant kernel should
1945	  continue to boot on existing non-UEFI platforms.
1946
1947endmenu
1948
1949config SYSVIPC_COMPAT
1950	def_bool y
1951	depends on COMPAT && SYSVIPC
1952
1953config ARCH_ENABLE_HUGEPAGE_MIGRATION
1954	def_bool y
1955	depends on HUGETLB_PAGE && MIGRATION
1956
1957config ARCH_ENABLE_THP_MIGRATION
1958	def_bool y
1959	depends on TRANSPARENT_HUGEPAGE
1960
1961menu "Power management options"
1962
1963source "kernel/power/Kconfig"
1964
1965config ARCH_HIBERNATION_POSSIBLE
1966	def_bool y
1967	depends on CPU_PM
1968
1969config ARCH_HIBERNATION_HEADER
1970	def_bool y
1971	depends on HIBERNATION
1972
1973config ARCH_SUSPEND_POSSIBLE
1974	def_bool y
1975
1976endmenu
1977
1978menu "CPU Power Management"
1979
1980source "drivers/cpuidle/Kconfig"
1981
1982source "drivers/cpufreq/Kconfig"
1983
1984endmenu
1985
1986source "drivers/firmware/Kconfig"
1987
1988source "drivers/acpi/Kconfig"
1989
1990source "arch/arm64/kvm/Kconfig"
1991
1992if CRYPTO
1993source "arch/arm64/crypto/Kconfig"
1994endif
1995