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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_CACHE_LINE_SIZE
15	select ARCH_HAS_DEBUG_VIRTUAL
16	select ARCH_HAS_DEBUG_VM_PGTABLE
17	select ARCH_HAS_DEVMEM_IS_ALLOWED
18	select ARCH_HAS_DMA_PREP_COHERENT
19	select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
20	select ARCH_HAS_FAST_MULTIPLIER
21	select ARCH_HAS_FORTIFY_SOURCE
22	select ARCH_HAS_GCOV_PROFILE_ALL
23	select ARCH_HAS_GIGANTIC_PAGE
24	select ARCH_HAS_KCOV
25	select ARCH_HAS_KEEPINITRD
26	select ARCH_HAS_MEMBARRIER_SYNC_CORE
27	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
28	select ARCH_HAS_PTE_DEVMAP
29	select ARCH_HAS_PTE_SPECIAL
30	select ARCH_HAS_SETUP_DMA_OPS
31	select ARCH_HAS_SET_DIRECT_MAP
32	select ARCH_HAS_SET_MEMORY
33	select ARCH_STACKWALK
34	select ARCH_HAS_STRICT_KERNEL_RWX
35	select ARCH_HAS_STRICT_MODULE_RWX
36	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
37	select ARCH_HAS_SYNC_DMA_FOR_CPU
38	select ARCH_HAS_SYSCALL_WRAPPER
39	select ARCH_HAS_TEARDOWN_DMA_OPS if IOMMU_SUPPORT
40	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
41	select ARCH_HAVE_ELF_PROT
42	select ARCH_HAVE_NMI_SAFE_CMPXCHG
43	select ARCH_INLINE_READ_LOCK if !PREEMPTION
44	select ARCH_INLINE_READ_LOCK_BH if !PREEMPTION
45	select ARCH_INLINE_READ_LOCK_IRQ if !PREEMPTION
46	select ARCH_INLINE_READ_LOCK_IRQSAVE if !PREEMPTION
47	select ARCH_INLINE_READ_UNLOCK if !PREEMPTION
48	select ARCH_INLINE_READ_UNLOCK_BH if !PREEMPTION
49	select ARCH_INLINE_READ_UNLOCK_IRQ if !PREEMPTION
50	select ARCH_INLINE_READ_UNLOCK_IRQRESTORE if !PREEMPTION
51	select ARCH_INLINE_WRITE_LOCK if !PREEMPTION
52	select ARCH_INLINE_WRITE_LOCK_BH if !PREEMPTION
53	select ARCH_INLINE_WRITE_LOCK_IRQ if !PREEMPTION
54	select ARCH_INLINE_WRITE_LOCK_IRQSAVE if !PREEMPTION
55	select ARCH_INLINE_WRITE_UNLOCK if !PREEMPTION
56	select ARCH_INLINE_WRITE_UNLOCK_BH if !PREEMPTION
57	select ARCH_INLINE_WRITE_UNLOCK_IRQ if !PREEMPTION
58	select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE if !PREEMPTION
59	select ARCH_INLINE_SPIN_TRYLOCK if !PREEMPTION
60	select ARCH_INLINE_SPIN_TRYLOCK_BH if !PREEMPTION
61	select ARCH_INLINE_SPIN_LOCK if !PREEMPTION
62	select ARCH_INLINE_SPIN_LOCK_BH if !PREEMPTION
63	select ARCH_INLINE_SPIN_LOCK_IRQ if !PREEMPTION
64	select ARCH_INLINE_SPIN_LOCK_IRQSAVE if !PREEMPTION
65	select ARCH_INLINE_SPIN_UNLOCK if !PREEMPTION
66	select ARCH_INLINE_SPIN_UNLOCK_BH if !PREEMPTION
67	select ARCH_INLINE_SPIN_UNLOCK_IRQ if !PREEMPTION
68	select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPTION
69	select ARCH_KEEP_MEMBLOCK
70	select ARCH_USE_CMPXCHG_LOCKREF
71	select ARCH_USE_GNU_PROPERTY
72	select ARCH_USE_QUEUED_RWLOCKS
73	select ARCH_USE_QUEUED_SPINLOCKS
74	select ARCH_USE_SYM_ANNOTATIONS
75	select ARCH_SUPPORTS_MEMORY_FAILURE
76	select ARCH_SUPPORTS_SHADOW_CALL_STACK if CC_HAVE_SHADOW_CALL_STACK
77	select ARCH_SUPPORTS_LTO_CLANG if CPU_LITTLE_ENDIAN
78	select ARCH_SUPPORTS_LTO_CLANG_THIN
79	select ARCH_SUPPORTS_CFI_CLANG
80	select ARCH_SUPPORTS_ATOMIC_RMW
81	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && (GCC_VERSION >= 50000 || CC_IS_CLANG)
82	select ARCH_SUPPORTS_NUMA_BALANCING
83	select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT
84	select ARCH_WANT_DEFAULT_BPF_JIT
85	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
86	select ARCH_WANT_FRAME_POINTERS
87	select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
88	select ARCH_WANT_LD_ORPHAN_WARN
89	select ARCH_HAS_UBSAN_SANITIZE_ALL
90	select ARM_AMBA
91	select ARM_ARCH_TIMER
92	select ARM_GIC
93	select AUDIT_ARCH_COMPAT_GENERIC
94	select ARM_GIC_V2M if PCI
95	select ARM_GIC_V3
96	select ARM_GIC_V3_ITS if PCI
97	select ARM_PSCI_FW
98	select BUILDTIME_TABLE_SORT
99	select CLONE_BACKWARDS
100	select COMMON_CLK
101	select CPU_PM if (SUSPEND || CPU_IDLE)
102	select CRC32
103	select DCACHE_WORD_ACCESS
104	select DMA_DIRECT_REMAP
105	select EDAC_SUPPORT
106	select FRAME_POINTER
107	select GENERIC_ALLOCATOR
108	select GENERIC_ARCH_TOPOLOGY
109	select GENERIC_CLOCKEVENTS
110	select GENERIC_CLOCKEVENTS_BROADCAST
111	select GENERIC_CPU_AUTOPROBE
112	select GENERIC_CPU_VULNERABILITIES
113	select GENERIC_EARLY_IOREMAP
114	select GENERIC_IDLE_POLL_SETUP
115	select GENERIC_IRQ_IPI
116	select GENERIC_IRQ_MULTI_HANDLER
117	select GENERIC_IRQ_PROBE
118	select GENERIC_IRQ_SHOW
119	select GENERIC_IRQ_SHOW_LEVEL
120	select GENERIC_PCI_IOMAP
121	select GENERIC_PTDUMP
122	select GENERIC_SCHED_CLOCK
123	select GENERIC_SMP_IDLE_THREAD
124	select GENERIC_STRNCPY_FROM_USER
125	select GENERIC_STRNLEN_USER
126	select GENERIC_TIME_VSYSCALL
127	select GENERIC_GETTIMEOFDAY
128	select GENERIC_VDSO_TIME_NS
129	select HANDLE_DOMAIN_IRQ
130	select HARDIRQS_SW_RESEND
131	select HAVE_MOVE_PMD
132	select HAVE_PCI
133	select HAVE_ACPI_APEI if (ACPI && EFI)
134	select HAVE_ALIGNED_STRUCT_PAGE if SLUB
135	select HAVE_ARCH_AUDITSYSCALL
136	select HAVE_ARCH_BITREVERSE
137	select HAVE_ARCH_COMPILER_H
138	select HAVE_ARCH_HUGE_VMAP
139	select HAVE_ARCH_JUMP_LABEL
140	select HAVE_ARCH_JUMP_LABEL_RELATIVE
141	select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48)
142	select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN
143	select HAVE_ARCH_KGDB
144	select HAVE_ARCH_MMAP_RND_BITS
145	select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
146	select HAVE_ARCH_PREL32_RELOCATIONS
147	select HAVE_ARCH_SECCOMP_FILTER
148	select HAVE_ARCH_STACKLEAK
149	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
150	select HAVE_ARCH_TRACEHOOK
151	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
152	select HAVE_ARCH_VMAP_STACK
153	select HAVE_ARM_SMCCC
154	select HAVE_ASM_MODVERSIONS
155	select HAVE_EBPF_JIT
156	select HAVE_C_RECORDMCOUNT
157	select HAVE_CMPXCHG_DOUBLE
158	select HAVE_CMPXCHG_LOCAL
159	select HAVE_CONTEXT_TRACKING
160	select HAVE_DEBUG_BUGVERBOSE
161	select HAVE_DEBUG_KMEMLEAK
162	select HAVE_DMA_CONTIGUOUS
163	select HAVE_DYNAMIC_FTRACE
164	select HAVE_DYNAMIC_FTRACE_WITH_REGS \
165		if $(cc-option,-fpatchable-function-entry=2)
166	select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY \
167		if DYNAMIC_FTRACE_WITH_REGS
168	select HAVE_EFFICIENT_UNALIGNED_ACCESS
169	select HAVE_FAST_GUP
170	select HAVE_FTRACE_MCOUNT_RECORD
171	select HAVE_FUNCTION_TRACER
172	select HAVE_FUNCTION_ERROR_INJECTION
173	select HAVE_FUNCTION_GRAPH_TRACER
174	select HAVE_GCC_PLUGINS
175	select HAVE_HW_BREAKPOINT if PERF_EVENTS
176	select HAVE_IRQ_TIME_ACCOUNTING
177	select HAVE_NMI
178	select HAVE_PATA_PLATFORM
179	select HAVE_PERF_EVENTS
180	select HAVE_PERF_REGS
181	select HAVE_PERF_USER_STACK_DUMP
182	select HAVE_REGS_AND_STACK_ACCESS_API
183	select HAVE_FUNCTION_ARG_ACCESS_API
184	select HAVE_FUTEX_CMPXCHG if FUTEX
185	select MMU_GATHER_RCU_TABLE_FREE
186	select HAVE_RSEQ
187	select HAVE_STACKPROTECTOR
188	select HAVE_SYSCALL_TRACEPOINTS
189	select HAVE_KPROBES
190	select HAVE_KRETPROBES
191	select HAVE_GENERIC_VDSO
192	select HOLES_IN_ZONE
193	select IOMMU_DMA if IOMMU_SUPPORT
194	select IRQ_DOMAIN
195	select IRQ_FORCED_THREADING
196	select MODULES_USE_ELF_RELA
197	select NEED_DMA_MAP_STATE
198	select NEED_SG_DMA_LENGTH
199	select OF
200	select OF_EARLY_FLATTREE
201	select PCI_DOMAINS_GENERIC if PCI
202	select PCI_ECAM if (ACPI && PCI)
203	select PCI_SYSCALL if PCI
204	select POWER_RESET
205	select POWER_SUPPLY
206	select SET_FS
207	select SPARSE_IRQ
208	select SWIOTLB
209	select SYSCTL_EXCEPTION_TRACE
210	select THREAD_INFO_IN_TASK
211	help
212	  ARM 64-bit (AArch64) Linux support.
213
214config 64BIT
215	def_bool y
216
217config MMU
218	def_bool y
219
220config ARM64_PAGE_SHIFT
221	int
222	default 16 if ARM64_64K_PAGES
223	default 14 if ARM64_16K_PAGES
224	default 12
225
226config ARM64_CONT_PTE_SHIFT
227	int
228	default 5 if ARM64_64K_PAGES
229	default 7 if ARM64_16K_PAGES
230	default 4
231
232config ARM64_CONT_PMD_SHIFT
233	int
234	default 5 if ARM64_64K_PAGES
235	default 5 if ARM64_16K_PAGES
236	default 4
237
238config ARCH_MMAP_RND_BITS_MIN
239       default 14 if ARM64_64K_PAGES
240       default 16 if ARM64_16K_PAGES
241       default 18
242
243# max bits determined by the following formula:
244#  VA_BITS - PAGE_SHIFT - 3
245config ARCH_MMAP_RND_BITS_MAX
246       default 19 if ARM64_VA_BITS=36
247       default 24 if ARM64_VA_BITS=39
248       default 27 if ARM64_VA_BITS=42
249       default 30 if ARM64_VA_BITS=47
250       default 29 if ARM64_VA_BITS=48 && ARM64_64K_PAGES
251       default 31 if ARM64_VA_BITS=48 && ARM64_16K_PAGES
252       default 33 if ARM64_VA_BITS=48
253       default 14 if ARM64_64K_PAGES
254       default 16 if ARM64_16K_PAGES
255       default 18
256
257config ARCH_MMAP_RND_COMPAT_BITS_MIN
258       default 7 if ARM64_64K_PAGES
259       default 9 if ARM64_16K_PAGES
260       default 11
261
262config ARCH_MMAP_RND_COMPAT_BITS_MAX
263       default 16
264
265config NO_IOPORT_MAP
266	def_bool y if !PCI
267
268config STACKTRACE_SUPPORT
269	def_bool y
270
271config ILLEGAL_POINTER_VALUE
272	hex
273	default 0xdead000000000000
274
275config LOCKDEP_SUPPORT
276	def_bool y
277
278config TRACE_IRQFLAGS_SUPPORT
279	def_bool y
280
281config GENERIC_BUG
282	def_bool y
283	depends on BUG
284
285config GENERIC_BUG_RELATIVE_POINTERS
286	def_bool y
287	depends on GENERIC_BUG
288
289config GENERIC_HWEIGHT
290	def_bool y
291
292config GENERIC_CSUM
293        def_bool y
294
295config GENERIC_CALIBRATE_DELAY
296	def_bool y
297
298config ZONE_DMA
299	bool "Support DMA zone" if EXPERT
300	default y
301
302config ZONE_DMA32
303	bool "Support DMA32 zone" if EXPERT
304	default y
305
306config ARCH_ENABLE_MEMORY_HOTPLUG
307	def_bool y
308
309config ARCH_ENABLE_MEMORY_HOTREMOVE
310	def_bool y
311
312config SMP
313	def_bool y
314
315config KERNEL_MODE_NEON
316	def_bool y
317
318config FIX_EARLYCON_MEM
319	def_bool y
320
321config PGTABLE_LEVELS
322	int
323	default 2 if ARM64_16K_PAGES && ARM64_VA_BITS_36
324	default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42
325	default 3 if ARM64_64K_PAGES && (ARM64_VA_BITS_48 || ARM64_VA_BITS_52)
326	default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39
327	default 3 if ARM64_16K_PAGES && ARM64_VA_BITS_47
328	default 4 if !ARM64_64K_PAGES && ARM64_VA_BITS_48
329
330config ARCH_SUPPORTS_UPROBES
331	def_bool y
332
333config ARCH_PROC_KCORE_TEXT
334	def_bool y
335
336config BROKEN_GAS_INST
337	def_bool !$(as-instr,1:\n.inst 0\n.rept . - 1b\n\nnop\n.endr\n)
338
339config KASAN_SHADOW_OFFSET
340	hex
341	depends on KASAN
342	default 0xdfffa00000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && !KASAN_SW_TAGS
343	default 0xdfffd00000000000 if ARM64_VA_BITS_47 && !KASAN_SW_TAGS
344	default 0xdffffe8000000000 if ARM64_VA_BITS_42 && !KASAN_SW_TAGS
345	default 0xdfffffd000000000 if ARM64_VA_BITS_39 && !KASAN_SW_TAGS
346	default 0xdffffffa00000000 if ARM64_VA_BITS_36 && !KASAN_SW_TAGS
347	default 0xefff900000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && KASAN_SW_TAGS
348	default 0xefffc80000000000 if ARM64_VA_BITS_47 && KASAN_SW_TAGS
349	default 0xeffffe4000000000 if ARM64_VA_BITS_42 && KASAN_SW_TAGS
350	default 0xefffffc800000000 if ARM64_VA_BITS_39 && KASAN_SW_TAGS
351	default 0xeffffff900000000 if ARM64_VA_BITS_36 && KASAN_SW_TAGS
352	default 0xffffffffffffffff
353
354source "arch/arm64/Kconfig.platforms"
355
356menu "Kernel Features"
357
358menu "ARM errata workarounds via the alternatives framework"
359
360config ARM64_WORKAROUND_CLEAN_CACHE
361	bool
362
363config ARM64_ERRATUM_826319
364	bool "Cortex-A53: 826319: System might deadlock if a write cannot complete until read data is accepted"
365	default y
366	select ARM64_WORKAROUND_CLEAN_CACHE
367	help
368	  This option adds an alternative code sequence to work around ARM
369	  erratum 826319 on Cortex-A53 parts up to r0p2 with an AMBA 4 ACE or
370	  AXI master interface and an L2 cache.
371
372	  If a Cortex-A53 uses an AMBA AXI4 ACE interface to other processors
373	  and is unable to accept a certain write via this interface, it will
374	  not progress on read data presented on the read data channel and the
375	  system can deadlock.
376
377	  The workaround promotes data cache clean instructions to
378	  data cache clean-and-invalidate.
379	  Please note that this does not necessarily enable the workaround,
380	  as it depends on the alternative framework, which will only patch
381	  the kernel if an affected CPU is detected.
382
383	  If unsure, say Y.
384
385config ARM64_ERRATUM_827319
386	bool "Cortex-A53: 827319: Data cache clean instructions might cause overlapping transactions to the interconnect"
387	default y
388	select ARM64_WORKAROUND_CLEAN_CACHE
389	help
390	  This option adds an alternative code sequence to work around ARM
391	  erratum 827319 on Cortex-A53 parts up to r0p2 with an AMBA 5 CHI
392	  master interface and an L2 cache.
393
394	  Under certain conditions this erratum can cause a clean line eviction
395	  to occur at the same time as another transaction to the same address
396	  on the AMBA 5 CHI interface, which can cause data corruption if the
397	  interconnect reorders the two transactions.
398
399	  The workaround promotes data cache clean instructions to
400	  data cache clean-and-invalidate.
401	  Please note that this does not necessarily enable the workaround,
402	  as it depends on the alternative framework, which will only patch
403	  the kernel if an affected CPU is detected.
404
405	  If unsure, say Y.
406
407config ARM64_ERRATUM_824069
408	bool "Cortex-A53: 824069: Cache line might not be marked as clean after a CleanShared snoop"
409	default y
410	select ARM64_WORKAROUND_CLEAN_CACHE
411	help
412	  This option adds an alternative code sequence to work around ARM
413	  erratum 824069 on Cortex-A53 parts up to r0p2 when it is connected
414	  to a coherent interconnect.
415
416	  If a Cortex-A53 processor is executing a store or prefetch for
417	  write instruction at the same time as a processor in another
418	  cluster is executing a cache maintenance operation to the same
419	  address, then this erratum might cause a clean cache line to be
420	  incorrectly marked as dirty.
421
422	  The workaround promotes data cache clean instructions to
423	  data cache clean-and-invalidate.
424	  Please note that this option does not necessarily enable the
425	  workaround, as it depends on the alternative framework, which will
426	  only patch the kernel if an affected CPU is detected.
427
428	  If unsure, say Y.
429
430config ARM64_ERRATUM_819472
431	bool "Cortex-A53: 819472: Store exclusive instructions might cause data corruption"
432	default y
433	select ARM64_WORKAROUND_CLEAN_CACHE
434	help
435	  This option adds an alternative code sequence to work around ARM
436	  erratum 819472 on Cortex-A53 parts up to r0p1 with an L2 cache
437	  present when it is connected to a coherent interconnect.
438
439	  If the processor is executing a load and store exclusive sequence at
440	  the same time as a processor in another cluster is executing a cache
441	  maintenance operation to the same address, then this erratum might
442	  cause data corruption.
443
444	  The workaround promotes data cache clean instructions to
445	  data cache clean-and-invalidate.
446	  Please note that this does not necessarily enable the workaround,
447	  as it depends on the alternative framework, which will only patch
448	  the kernel if an affected CPU is detected.
449
450	  If unsure, say Y.
451
452config ARM64_ERRATUM_832075
453	bool "Cortex-A57: 832075: possible deadlock on mixing exclusive memory accesses with device loads"
454	default y
455	help
456	  This option adds an alternative code sequence to work around ARM
457	  erratum 832075 on Cortex-A57 parts up to r1p2.
458
459	  Affected Cortex-A57 parts might deadlock when exclusive load/store
460	  instructions to Write-Back memory are mixed with Device loads.
461
462	  The workaround is to promote device loads to use Load-Acquire
463	  semantics.
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
470config ARM64_ERRATUM_834220
471	bool "Cortex-A57: 834220: Stage 2 translation fault might be incorrectly reported in presence of a Stage 1 fault"
472	depends on KVM
473	default y
474	help
475	  This option adds an alternative code sequence to work around ARM
476	  erratum 834220 on Cortex-A57 parts up to r1p2.
477
478	  Affected Cortex-A57 parts might report a Stage 2 translation
479	  fault as the result of a Stage 1 fault for load crossing a
480	  page boundary when there is a permission or device memory
481	  alignment fault at Stage 1 and a translation fault at Stage 2.
482
483	  The workaround is to verify that the Stage 1 translation
484	  doesn't generate a fault before handling the Stage 2 fault.
485	  Please note that this does not necessarily enable the workaround,
486	  as it depends on the alternative framework, which will only patch
487	  the kernel if an affected CPU is detected.
488
489	  If unsure, say Y.
490
491config ARM64_ERRATUM_1742098
492	bool "Cortex-A57/A72: 1742098: ELR recorded incorrectly on interrupt taken between cryptographic instructions in a sequence"
493	depends on COMPAT
494	default y
495	help
496	  This option removes the AES hwcap for aarch32 user-space to
497	  workaround erratum 1742098 on Cortex-A57 and Cortex-A72.
498
499	  Affected parts may corrupt the AES state if an interrupt is
500	  taken between a pair of AES instructions. These instructions
501	  are only present if the cryptography extensions are present.
502	  All software should have a fallback implementation for CPUs
503	  that don't implement the cryptography extensions.
504
505	  If unsure, say Y.
506
507config ARM64_ERRATUM_845719
508	bool "Cortex-A53: 845719: a load might read incorrect data"
509	depends on COMPAT
510	default y
511	help
512	  This option adds an alternative code sequence to work around ARM
513	  erratum 845719 on Cortex-A53 parts up to r0p4.
514
515	  When running a compat (AArch32) userspace on an affected Cortex-A53
516	  part, a load at EL0 from a virtual address that matches the bottom 32
517	  bits of the virtual address used by a recent load at (AArch64) EL1
518	  might return incorrect data.
519
520	  The workaround is to write the contextidr_el1 register on exception
521	  return to a 32-bit task.
522	  Please note that this does not necessarily enable the workaround,
523	  as it depends on the alternative framework, which will only patch
524	  the kernel if an affected CPU is detected.
525
526	  If unsure, say Y.
527
528config ARM64_ERRATUM_843419
529	bool "Cortex-A53: 843419: A load or store might access an incorrect address"
530	default y
531	select ARM64_MODULE_PLTS if MODULES
532	help
533	  This option links the kernel with '--fix-cortex-a53-843419' and
534	  enables PLT support to replace certain ADRP instructions, which can
535	  cause subsequent memory accesses to use an incorrect address on
536	  Cortex-A53 parts up to r0p4.
537
538	  If unsure, say Y.
539
540config ARM64_ERRATUM_1024718
541	bool "Cortex-A55: 1024718: Update of DBM/AP bits without break before make might result in incorrect update"
542	default y
543	help
544	  This option adds a workaround for ARM Cortex-A55 Erratum 1024718.
545
546	  Affected Cortex-A55 cores (all revisions) could cause incorrect
547	  update of the hardware dirty bit when the DBM/AP bits are updated
548	  without a break-before-make. The workaround is to disable the usage
549	  of hardware DBM locally on the affected cores. CPUs not affected by
550	  this erratum will continue to use the feature.
551
552	  If unsure, say Y.
553
554config ARM64_ERRATUM_1418040
555	bool "Cortex-A76/Neoverse-N1: MRC read following MRRC read of specific Generic Timer in AArch32 might give incorrect result"
556	default y
557	depends on COMPAT
558	help
559	  This option adds a workaround for ARM Cortex-A76/Neoverse-N1
560	  errata 1188873 and 1418040.
561
562	  Affected Cortex-A76/Neoverse-N1 cores (r0p0 to r3p1) could
563	  cause register corruption when accessing the timer registers
564	  from AArch32 userspace.
565
566	  If unsure, say Y.
567
568config ARM64_WORKAROUND_SPECULATIVE_AT
569	bool
570
571config ARM64_ERRATUM_1165522
572	bool "Cortex-A76: 1165522: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
573	default y
574	select ARM64_WORKAROUND_SPECULATIVE_AT
575	help
576	  This option adds a workaround for ARM Cortex-A76 erratum 1165522.
577
578	  Affected Cortex-A76 cores (r0p0, r1p0, r2p0) could end-up with
579	  corrupted TLBs by speculating an AT instruction during a guest
580	  context switch.
581
582	  If unsure, say Y.
583
584config ARM64_ERRATUM_1319367
585	bool "Cortex-A57/A72: 1319537: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
586	default y
587	select ARM64_WORKAROUND_SPECULATIVE_AT
588	help
589	  This option adds work arounds for ARM Cortex-A57 erratum 1319537
590	  and A72 erratum 1319367
591
592	  Cortex-A57 and A72 cores could end-up with corrupted TLBs by
593	  speculating an AT instruction during a guest context switch.
594
595	  If unsure, say Y.
596
597config ARM64_ERRATUM_1530923
598	bool "Cortex-A55: 1530923: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
599	default y
600	select ARM64_WORKAROUND_SPECULATIVE_AT
601	help
602	  This option adds a workaround for ARM Cortex-A55 erratum 1530923.
603
604	  Affected Cortex-A55 cores (r0p0, r0p1, r1p0, r2p0) could end-up with
605	  corrupted TLBs by speculating an AT instruction during a guest
606	  context switch.
607
608	  If unsure, say Y.
609
610config ARM64_WORKAROUND_REPEAT_TLBI
611	bool
612
613config ARM64_ERRATUM_1286807
614	bool "Cortex-A76: Modification of the translation table for a virtual address might lead to read-after-read ordering violation"
615	default y
616	select ARM64_WORKAROUND_REPEAT_TLBI
617	help
618	  This option adds a workaround for ARM Cortex-A76 erratum 1286807.
619
620	  On the affected Cortex-A76 cores (r0p0 to r3p0), if a virtual
621	  address for a cacheable mapping of a location is being
622	  accessed by a core while another core is remapping the virtual
623	  address to a new physical page using the recommended
624	  break-before-make sequence, then under very rare circumstances
625	  TLBI+DSB completes before a read using the translation being
626	  invalidated has been observed by other observers. The
627	  workaround repeats the TLBI+DSB operation.
628
629config ARM64_ERRATUM_1463225
630	bool "Cortex-A76: Software Step might prevent interrupt recognition"
631	default y
632	help
633	  This option adds a workaround for Arm Cortex-A76 erratum 1463225.
634
635	  On the affected Cortex-A76 cores (r0p0 to r3p1), software stepping
636	  of a system call instruction (SVC) can prevent recognition of
637	  subsequent interrupts when software stepping is disabled in the
638	  exception handler of the system call and either kernel debugging
639	  is enabled or VHE is in use.
640
641	  Work around the erratum by triggering a dummy step exception
642	  when handling a system call from a task that is being stepped
643	  in a VHE configuration of the kernel.
644
645	  If unsure, say Y.
646
647config ARM64_ERRATUM_1542419
648	bool "Neoverse-N1: workaround mis-ordering of instruction fetches"
649	default y
650	help
651	  This option adds a workaround for ARM Neoverse-N1 erratum
652	  1542419.
653
654	  Affected Neoverse-N1 cores could execute a stale instruction when
655	  modified by another CPU. The workaround depends on a firmware
656	  counterpart.
657
658	  Workaround the issue by hiding the DIC feature from EL0. This
659	  forces user-space to perform cache maintenance.
660
661	  If unsure, say Y.
662
663config ARM64_ERRATUM_1508412
664	bool "Cortex-A77: 1508412: workaround deadlock on sequence of NC/Device load and store exclusive or PAR read"
665	default y
666	help
667	  This option adds a workaround for Arm Cortex-A77 erratum 1508412.
668
669	  Affected Cortex-A77 cores (r0p0, r1p0) could deadlock on a sequence
670	  of a store-exclusive or read of PAR_EL1 and a load with device or
671	  non-cacheable memory attributes. The workaround depends on a firmware
672	  counterpart.
673
674	  KVM guests must also have the workaround implemented or they can
675	  deadlock the system.
676
677	  Work around the issue by inserting DMB SY barriers around PAR_EL1
678	  register reads and warning KVM users. The DMB barrier is sufficient
679	  to prevent a speculative PAR_EL1 read.
680
681	  If unsure, say Y.
682
683config ARM64_ERRATUM_2457168
684	bool "Cortex-A510: 2457168: workaround for AMEVCNTR01 incrementing incorrectly"
685	depends on ARM64_AMU_EXTN
686	default y
687	help
688	  This option adds the workaround for ARM Cortex-A510 erratum 2457168.
689
690	  The AMU counter AMEVCNTR01 (constant counter) should increment at the same rate
691	  as the system counter. On affected Cortex-A510 cores AMEVCNTR01 increments
692	  incorrectly giving a significantly higher output value.
693
694	  Work around this problem by keeping the reference values of affected counters
695	  to 0 thus signaling an error case. This effect is the same to firmware disabling
696	  affected counters, in which case 0 will be returned when reading the disabled
697	  counters.
698
699	  If unsure, say Y.
700
701config CAVIUM_ERRATUM_22375
702	bool "Cavium erratum 22375, 24313"
703	default y
704	help
705	  Enable workaround for errata 22375 and 24313.
706
707	  This implements two gicv3-its errata workarounds for ThunderX. Both
708	  with a small impact affecting only ITS table allocation.
709
710	    erratum 22375: only alloc 8MB table size
711	    erratum 24313: ignore memory access type
712
713	  The fixes are in ITS initialization and basically ignore memory access
714	  type and table size provided by the TYPER and BASER registers.
715
716	  If unsure, say Y.
717
718config CAVIUM_ERRATUM_23144
719	bool "Cavium erratum 23144: ITS SYNC hang on dual socket system"
720	depends on NUMA
721	default y
722	help
723	  ITS SYNC command hang for cross node io and collections/cpu mapping.
724
725	  If unsure, say Y.
726
727config CAVIUM_ERRATUM_23154
728	bool "Cavium erratum 23154: Access to ICC_IAR1_EL1 is not sync'ed"
729	default y
730	help
731	  The gicv3 of ThunderX requires a modified version for
732	  reading the IAR status to ensure data synchronization
733	  (access to icc_iar1_el1 is not sync'ed before and after).
734
735	  If unsure, say Y.
736
737config CAVIUM_ERRATUM_27456
738	bool "Cavium erratum 27456: Broadcast TLBI instructions may cause icache corruption"
739	default y
740	help
741	  On ThunderX T88 pass 1.x through 2.1 parts, broadcast TLBI
742	  instructions may cause the icache to become corrupted if it
743	  contains data for a non-current ASID.  The fix is to
744	  invalidate the icache when changing the mm context.
745
746	  If unsure, say Y.
747
748config CAVIUM_ERRATUM_30115
749	bool "Cavium erratum 30115: Guest may disable interrupts in host"
750	default y
751	help
752	  On ThunderX T88 pass 1.x through 2.2, T81 pass 1.0 through
753	  1.2, and T83 Pass 1.0, KVM guest execution may disable
754	  interrupts in host. Trapping both GICv3 group-0 and group-1
755	  accesses sidesteps the issue.
756
757	  If unsure, say Y.
758
759config CAVIUM_TX2_ERRATUM_219
760	bool "Cavium ThunderX2 erratum 219: PRFM between TTBR change and ISB fails"
761	default y
762	help
763	  On Cavium ThunderX2, a load, store or prefetch instruction between a
764	  TTBR update and the corresponding context synchronizing operation can
765	  cause a spurious Data Abort to be delivered to any hardware thread in
766	  the CPU core.
767
768	  Work around the issue by avoiding the problematic code sequence and
769	  trapping KVM guest TTBRx_EL1 writes to EL2 when SMT is enabled. The
770	  trap handler performs the corresponding register access, skips the
771	  instruction and ensures context synchronization by virtue of the
772	  exception return.
773
774	  If unsure, say Y.
775
776config FUJITSU_ERRATUM_010001
777	bool "Fujitsu-A64FX erratum E#010001: Undefined fault may occur wrongly"
778	default y
779	help
780	  This option adds a workaround for Fujitsu-A64FX erratum E#010001.
781	  On some variants of the Fujitsu-A64FX cores ver(1.0, 1.1), memory
782	  accesses may cause undefined fault (Data abort, DFSC=0b111111).
783	  This fault occurs under a specific hardware condition when a
784	  load/store instruction performs an address translation using:
785	  case-1  TTBR0_EL1 with TCR_EL1.NFD0 == 1.
786	  case-2  TTBR0_EL2 with TCR_EL2.NFD0 == 1.
787	  case-3  TTBR1_EL1 with TCR_EL1.NFD1 == 1.
788	  case-4  TTBR1_EL2 with TCR_EL2.NFD1 == 1.
789
790	  The workaround is to ensure these bits are clear in TCR_ELx.
791	  The workaround only affects the Fujitsu-A64FX.
792
793	  If unsure, say Y.
794
795config HISILICON_ERRATUM_161600802
796	bool "Hip07 161600802: Erroneous redistributor VLPI base"
797	default y
798	help
799	  The HiSilicon Hip07 SoC uses the wrong redistributor base
800	  when issued ITS commands such as VMOVP and VMAPP, and requires
801	  a 128kB offset to be applied to the target address in this commands.
802
803	  If unsure, say Y.
804
805config QCOM_FALKOR_ERRATUM_1003
806	bool "Falkor E1003: Incorrect translation due to ASID change"
807	default y
808	help
809	  On Falkor v1, an incorrect ASID may be cached in the TLB when ASID
810	  and BADDR are changed together in TTBRx_EL1. Since we keep the ASID
811	  in TTBR1_EL1, this situation only occurs in the entry trampoline and
812	  then only for entries in the walk cache, since the leaf translation
813	  is unchanged. Work around the erratum by invalidating the walk cache
814	  entries for the trampoline before entering the kernel proper.
815
816config QCOM_FALKOR_ERRATUM_1009
817	bool "Falkor E1009: Prematurely complete a DSB after a TLBI"
818	default y
819	select ARM64_WORKAROUND_REPEAT_TLBI
820	help
821	  On Falkor v1, the CPU may prematurely complete a DSB following a
822	  TLBI xxIS invalidate maintenance operation. Repeat the TLBI operation
823	  one more time to fix the issue.
824
825	  If unsure, say Y.
826
827config QCOM_QDF2400_ERRATUM_0065
828	bool "QDF2400 E0065: Incorrect GITS_TYPER.ITT_Entry_size"
829	default y
830	help
831	  On Qualcomm Datacenter Technologies QDF2400 SoC, ITS hardware reports
832	  ITE size incorrectly. The GITS_TYPER.ITT_Entry_size field should have
833	  been indicated as 16Bytes (0xf), not 8Bytes (0x7).
834
835	  If unsure, say Y.
836
837config QCOM_FALKOR_ERRATUM_E1041
838	bool "Falkor E1041: Speculative instruction fetches might cause errant memory access"
839	default y
840	help
841	  Falkor CPU may speculatively fetch instructions from an improper
842	  memory location when MMU translation is changed from SCTLR_ELn[M]=1
843	  to SCTLR_ELn[M]=0. Prefix an ISB instruction to fix the problem.
844
845	  If unsure, say Y.
846
847config SOCIONEXT_SYNQUACER_PREITS
848	bool "Socionext Synquacer: Workaround for GICv3 pre-ITS"
849	default y
850	help
851	  Socionext Synquacer SoCs implement a separate h/w block to generate
852	  MSI doorbell writes with non-zero values for the device ID.
853
854	  If unsure, say Y.
855
856endmenu
857
858
859choice
860	prompt "Page size"
861	default ARM64_4K_PAGES
862	help
863	  Page size (translation granule) configuration.
864
865config ARM64_4K_PAGES
866	bool "4KB"
867	help
868	  This feature enables 4KB pages support.
869
870config ARM64_16K_PAGES
871	bool "16KB"
872	help
873	  The system will use 16KB pages support. AArch32 emulation
874	  requires applications compiled with 16K (or a multiple of 16K)
875	  aligned segments.
876
877config ARM64_64K_PAGES
878	bool "64KB"
879	help
880	  This feature enables 64KB pages support (4KB by default)
881	  allowing only two levels of page tables and faster TLB
882	  look-up. AArch32 emulation requires applications compiled
883	  with 64K aligned segments.
884
885endchoice
886
887choice
888	prompt "Virtual address space size"
889	default ARM64_VA_BITS_39 if ARM64_4K_PAGES
890	default ARM64_VA_BITS_47 if ARM64_16K_PAGES
891	default ARM64_VA_BITS_42 if ARM64_64K_PAGES
892	help
893	  Allows choosing one of multiple possible virtual address
894	  space sizes. The level of translation table is determined by
895	  a combination of page size and virtual address space size.
896
897config ARM64_VA_BITS_36
898	bool "36-bit" if EXPERT
899	depends on ARM64_16K_PAGES
900
901config ARM64_VA_BITS_39
902	bool "39-bit"
903	depends on ARM64_4K_PAGES
904
905config ARM64_VA_BITS_42
906	bool "42-bit"
907	depends on ARM64_64K_PAGES
908
909config ARM64_VA_BITS_47
910	bool "47-bit"
911	depends on ARM64_16K_PAGES
912
913config ARM64_VA_BITS_48
914	bool "48-bit"
915
916config ARM64_VA_BITS_52
917	bool "52-bit"
918	depends on ARM64_64K_PAGES && (ARM64_PAN || !ARM64_SW_TTBR0_PAN)
919	help
920	  Enable 52-bit virtual addressing for userspace when explicitly
921	  requested via a hint to mmap(). The kernel will also use 52-bit
922	  virtual addresses for its own mappings (provided HW support for
923	  this feature is available, otherwise it reverts to 48-bit).
924
925	  NOTE: Enabling 52-bit virtual addressing in conjunction with
926	  ARMv8.3 Pointer Authentication will result in the PAC being
927	  reduced from 7 bits to 3 bits, which may have a significant
928	  impact on its susceptibility to brute-force attacks.
929
930	  If unsure, select 48-bit virtual addressing instead.
931
932endchoice
933
934config ARM64_FORCE_52BIT
935	bool "Force 52-bit virtual addresses for userspace"
936	depends on ARM64_VA_BITS_52 && EXPERT
937	help
938	  For systems with 52-bit userspace VAs enabled, the kernel will attempt
939	  to maintain compatibility with older software by providing 48-bit VAs
940	  unless a hint is supplied to mmap.
941
942	  This configuration option disables the 48-bit compatibility logic, and
943	  forces all userspace addresses to be 52-bit on HW that supports it. One
944	  should only enable this configuration option for stress testing userspace
945	  memory management code. If unsure say N here.
946
947config ARM64_VA_BITS
948	int
949	default 36 if ARM64_VA_BITS_36
950	default 39 if ARM64_VA_BITS_39
951	default 42 if ARM64_VA_BITS_42
952	default 47 if ARM64_VA_BITS_47
953	default 48 if ARM64_VA_BITS_48
954	default 52 if ARM64_VA_BITS_52
955
956choice
957	prompt "Physical address space size"
958	default ARM64_PA_BITS_48
959	help
960	  Choose the maximum physical address range that the kernel will
961	  support.
962
963config ARM64_PA_BITS_48
964	bool "48-bit"
965
966config ARM64_PA_BITS_52
967	bool "52-bit (ARMv8.2)"
968	depends on ARM64_64K_PAGES
969	depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
970	help
971	  Enable support for a 52-bit physical address space, introduced as
972	  part of the ARMv8.2-LPA extension.
973
974	  With this enabled, the kernel will also continue to work on CPUs that
975	  do not support ARMv8.2-LPA, but with some added memory overhead (and
976	  minor performance overhead).
977
978endchoice
979
980config ARM64_PA_BITS
981	int
982	default 48 if ARM64_PA_BITS_48
983	default 52 if ARM64_PA_BITS_52
984
985choice
986	prompt "Endianness"
987	default CPU_LITTLE_ENDIAN
988	help
989	  Select the endianness of data accesses performed by the CPU. Userspace
990	  applications will need to be compiled and linked for the endianness
991	  that is selected here.
992
993config CPU_BIG_ENDIAN
994	bool "Build big-endian kernel"
995	depends on !LD_IS_LLD || LLD_VERSION >= 130000
996	# https://github.com/llvm/llvm-project/commit/1379b150991f70a5782e9a143c2ba5308da1161c
997	depends on AS_IS_GNU || AS_VERSION >= 150000
998	help
999	  Say Y if you plan on running a kernel with a big-endian userspace.
1000
1001config CPU_LITTLE_ENDIAN
1002	bool "Build little-endian kernel"
1003	help
1004	  Say Y if you plan on running a kernel with a little-endian userspace.
1005	  This is usually the case for distributions targeting arm64.
1006
1007endchoice
1008
1009config SCHED_MC
1010	bool "Multi-core scheduler support"
1011	help
1012	  Multi-core scheduler support improves the CPU scheduler's decision
1013	  making when dealing with multi-core CPU chips at a cost of slightly
1014	  increased overhead in some places. If unsure say N here.
1015
1016config SCHED_SMT
1017	bool "SMT scheduler support"
1018	help
1019	  Improves the CPU scheduler's decision making when dealing with
1020	  MultiThreading at a cost of slightly increased overhead in some
1021	  places. If unsure say N here.
1022
1023config NR_CPUS
1024	int "Maximum number of CPUs (2-4096)"
1025	range 2 4096
1026	default "256"
1027
1028config HOTPLUG_CPU
1029	bool "Support for hot-pluggable CPUs"
1030	select GENERIC_IRQ_MIGRATION
1031	help
1032	  Say Y here to experiment with turning CPUs off and on.  CPUs
1033	  can be controlled through /sys/devices/system/cpu.
1034
1035# Common NUMA Features
1036config NUMA
1037	bool "NUMA Memory Allocation and Scheduler Support"
1038	select ACPI_NUMA if ACPI
1039	select OF_NUMA
1040	help
1041	  Enable NUMA (Non-Uniform Memory Access) support.
1042
1043	  The kernel will try to allocate memory used by a CPU on the
1044	  local memory of the CPU and add some more
1045	  NUMA awareness to the kernel.
1046
1047config NODES_SHIFT
1048	int "Maximum NUMA Nodes (as a power of 2)"
1049	range 1 10
1050	default "4"
1051	depends on NEED_MULTIPLE_NODES
1052	help
1053	  Specify the maximum number of NUMA Nodes available on the target
1054	  system.  Increases memory reserved to accommodate various tables.
1055
1056config USE_PERCPU_NUMA_NODE_ID
1057	def_bool y
1058	depends on NUMA
1059
1060config HAVE_SETUP_PER_CPU_AREA
1061	def_bool y
1062	depends on NUMA
1063
1064config NEED_PER_CPU_EMBED_FIRST_CHUNK
1065	def_bool y
1066	depends on NUMA
1067
1068source "kernel/Kconfig.hz"
1069
1070config ARCH_SUPPORTS_DEBUG_PAGEALLOC
1071	def_bool y
1072
1073config ARCH_SPARSEMEM_ENABLE
1074	def_bool y
1075	select SPARSEMEM_VMEMMAP_ENABLE
1076
1077config ARCH_SPARSEMEM_DEFAULT
1078	def_bool ARCH_SPARSEMEM_ENABLE
1079
1080config ARCH_SELECT_MEMORY_MODEL
1081	def_bool ARCH_SPARSEMEM_ENABLE
1082
1083config ARCH_FLATMEM_ENABLE
1084	def_bool !NUMA
1085
1086config HAVE_ARCH_PFN_VALID
1087	def_bool y
1088
1089config HW_PERF_EVENTS
1090	def_bool y
1091	depends on ARM_PMU
1092
1093config SYS_SUPPORTS_HUGETLBFS
1094	def_bool y
1095
1096config ARCH_WANT_HUGE_PMD_SHARE
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