xref: /openbmc/linux/arch/arm64/Kconfig (revision 10756dc5)
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_CORRECT_STACKTRACE_ON_KRETPROBE
15	select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION
16	select ARCH_ENABLE_MEMORY_HOTPLUG
17	select ARCH_ENABLE_MEMORY_HOTREMOVE
18	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
19	select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE
20	select ARCH_HAS_CACHE_LINE_SIZE
21	select ARCH_HAS_DEBUG_VIRTUAL
22	select ARCH_HAS_DEBUG_VM_PGTABLE
23	select ARCH_HAS_DMA_PREP_COHERENT
24	select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
25	select ARCH_HAS_FAST_MULTIPLIER
26	select ARCH_HAS_FORTIFY_SOURCE
27	select ARCH_HAS_GCOV_PROFILE_ALL
28	select ARCH_HAS_GIGANTIC_PAGE
29	select ARCH_HAS_KCOV
30	select ARCH_HAS_KEEPINITRD
31	select ARCH_HAS_MEMBARRIER_SYNC_CORE
32	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
33	select ARCH_HAS_PTE_DEVMAP
34	select ARCH_HAS_PTE_SPECIAL
35	select ARCH_HAS_SETUP_DMA_OPS
36	select ARCH_HAS_SET_DIRECT_MAP
37	select ARCH_HAS_SET_MEMORY
38	select ARCH_STACKWALK
39	select ARCH_HAS_STRICT_KERNEL_RWX
40	select ARCH_HAS_STRICT_MODULE_RWX
41	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
42	select ARCH_HAS_SYNC_DMA_FOR_CPU
43	select ARCH_HAS_SYSCALL_WRAPPER
44	select ARCH_HAS_TEARDOWN_DMA_OPS if IOMMU_SUPPORT
45	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
46	select ARCH_HAS_ZONE_DMA_SET if EXPERT
47	select ARCH_HAVE_ELF_PROT
48	select ARCH_HAVE_NMI_SAFE_CMPXCHG
49	select ARCH_INLINE_READ_LOCK if !PREEMPTION
50	select ARCH_INLINE_READ_LOCK_BH if !PREEMPTION
51	select ARCH_INLINE_READ_LOCK_IRQ if !PREEMPTION
52	select ARCH_INLINE_READ_LOCK_IRQSAVE if !PREEMPTION
53	select ARCH_INLINE_READ_UNLOCK if !PREEMPTION
54	select ARCH_INLINE_READ_UNLOCK_BH if !PREEMPTION
55	select ARCH_INLINE_READ_UNLOCK_IRQ if !PREEMPTION
56	select ARCH_INLINE_READ_UNLOCK_IRQRESTORE if !PREEMPTION
57	select ARCH_INLINE_WRITE_LOCK if !PREEMPTION
58	select ARCH_INLINE_WRITE_LOCK_BH if !PREEMPTION
59	select ARCH_INLINE_WRITE_LOCK_IRQ if !PREEMPTION
60	select ARCH_INLINE_WRITE_LOCK_IRQSAVE if !PREEMPTION
61	select ARCH_INLINE_WRITE_UNLOCK if !PREEMPTION
62	select ARCH_INLINE_WRITE_UNLOCK_BH if !PREEMPTION
63	select ARCH_INLINE_WRITE_UNLOCK_IRQ if !PREEMPTION
64	select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE if !PREEMPTION
65	select ARCH_INLINE_SPIN_TRYLOCK if !PREEMPTION
66	select ARCH_INLINE_SPIN_TRYLOCK_BH if !PREEMPTION
67	select ARCH_INLINE_SPIN_LOCK if !PREEMPTION
68	select ARCH_INLINE_SPIN_LOCK_BH if !PREEMPTION
69	select ARCH_INLINE_SPIN_LOCK_IRQ if !PREEMPTION
70	select ARCH_INLINE_SPIN_LOCK_IRQSAVE if !PREEMPTION
71	select ARCH_INLINE_SPIN_UNLOCK if !PREEMPTION
72	select ARCH_INLINE_SPIN_UNLOCK_BH if !PREEMPTION
73	select ARCH_INLINE_SPIN_UNLOCK_IRQ if !PREEMPTION
74	select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPTION
75	select ARCH_KEEP_MEMBLOCK
76	select ARCH_USE_CMPXCHG_LOCKREF
77	select ARCH_USE_GNU_PROPERTY
78	select ARCH_USE_MEMTEST
79	select ARCH_USE_QUEUED_RWLOCKS
80	select ARCH_USE_QUEUED_SPINLOCKS
81	select ARCH_USE_SYM_ANNOTATIONS
82	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
83	select ARCH_SUPPORTS_HUGETLBFS
84	select ARCH_SUPPORTS_MEMORY_FAILURE
85	select ARCH_SUPPORTS_SHADOW_CALL_STACK if CC_HAVE_SHADOW_CALL_STACK
86	select ARCH_SUPPORTS_LTO_CLANG if CPU_LITTLE_ENDIAN
87	select ARCH_SUPPORTS_LTO_CLANG_THIN
88	select ARCH_SUPPORTS_CFI_CLANG
89	select ARCH_SUPPORTS_ATOMIC_RMW
90	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
91	select ARCH_SUPPORTS_NUMA_BALANCING
92	select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT
93	select ARCH_WANT_DEFAULT_BPF_JIT
94	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
95	select ARCH_WANT_FRAME_POINTERS
96	select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
97	select ARCH_WANT_LD_ORPHAN_WARN
98	select ARCH_WANTS_NO_INSTR
99	select ARCH_HAS_UBSAN_SANITIZE_ALL
100	select ARM_AMBA
101	select ARM_ARCH_TIMER
102	select ARM_GIC
103	select AUDIT_ARCH_COMPAT_GENERIC
104	select ARM_GIC_V2M if PCI
105	select ARM_GIC_V3
106	select ARM_GIC_V3_ITS if PCI
107	select ARM_PSCI_FW
108	select BUILDTIME_TABLE_SORT
109	select CLONE_BACKWARDS
110	select COMMON_CLK
111	select CPU_PM if (SUSPEND || CPU_IDLE)
112	select CRC32
113	select DCACHE_WORD_ACCESS
114	select DMA_DIRECT_REMAP
115	select EDAC_SUPPORT
116	select FRAME_POINTER
117	select GENERIC_ALLOCATOR
118	select GENERIC_ARCH_TOPOLOGY
119	select GENERIC_CLOCKEVENTS_BROADCAST
120	select GENERIC_CPU_AUTOPROBE
121	select GENERIC_CPU_VULNERABILITIES
122	select GENERIC_EARLY_IOREMAP
123	select GENERIC_FIND_FIRST_BIT
124	select GENERIC_IDLE_POLL_SETUP
125	select GENERIC_IRQ_IPI
126	select GENERIC_IRQ_PROBE
127	select GENERIC_IRQ_SHOW
128	select GENERIC_IRQ_SHOW_LEVEL
129	select GENERIC_LIB_DEVMEM_IS_ALLOWED
130	select GENERIC_PCI_IOMAP
131	select GENERIC_PTDUMP
132	select GENERIC_SCHED_CLOCK
133	select GENERIC_SMP_IDLE_THREAD
134	select GENERIC_TIME_VSYSCALL
135	select GENERIC_GETTIMEOFDAY
136	select GENERIC_VDSO_TIME_NS
137	select HARDIRQS_SW_RESEND
138	select HAVE_MOVE_PMD
139	select HAVE_MOVE_PUD
140	select HAVE_PCI
141	select HAVE_ACPI_APEI if (ACPI && EFI)
142	select HAVE_ALIGNED_STRUCT_PAGE if SLUB
143	select HAVE_ARCH_AUDITSYSCALL
144	select HAVE_ARCH_BITREVERSE
145	select HAVE_ARCH_COMPILER_H
146	select HAVE_ARCH_HUGE_VMAP
147	select HAVE_ARCH_JUMP_LABEL
148	select HAVE_ARCH_JUMP_LABEL_RELATIVE
149	select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48)
150	select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN
151	select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN
152	select HAVE_ARCH_KASAN_HW_TAGS if (HAVE_ARCH_KASAN && ARM64_MTE)
153	# Some instrumentation may be unsound, hence EXPERT
154	select HAVE_ARCH_KCSAN if EXPERT
155	select HAVE_ARCH_KFENCE
156	select HAVE_ARCH_KGDB
157	select HAVE_ARCH_MMAP_RND_BITS
158	select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
159	select HAVE_ARCH_PREL32_RELOCATIONS
160	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
161	select HAVE_ARCH_SECCOMP_FILTER
162	select HAVE_ARCH_STACKLEAK
163	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
164	select HAVE_ARCH_TRACEHOOK
165	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
166	select HAVE_ARCH_VMAP_STACK
167	select HAVE_ARM_SMCCC
168	select HAVE_ASM_MODVERSIONS
169	select HAVE_EBPF_JIT
170	select HAVE_C_RECORDMCOUNT
171	select HAVE_CMPXCHG_DOUBLE
172	select HAVE_CMPXCHG_LOCAL
173	select HAVE_CONTEXT_TRACKING
174	select HAVE_DEBUG_KMEMLEAK
175	select HAVE_DMA_CONTIGUOUS
176	select HAVE_DYNAMIC_FTRACE
177	select HAVE_DYNAMIC_FTRACE_WITH_REGS \
178		if $(cc-option,-fpatchable-function-entry=2)
179	select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY \
180		if DYNAMIC_FTRACE_WITH_REGS
181	select HAVE_EFFICIENT_UNALIGNED_ACCESS
182	select HAVE_FAST_GUP
183	select HAVE_FTRACE_MCOUNT_RECORD
184	select HAVE_FUNCTION_TRACER
185	select HAVE_FUNCTION_ERROR_INJECTION
186	select HAVE_FUNCTION_GRAPH_TRACER
187	select HAVE_GCC_PLUGINS
188	select HAVE_HW_BREAKPOINT if PERF_EVENTS
189	select HAVE_IRQ_TIME_ACCOUNTING
190	select HAVE_KVM
191	select HAVE_NMI
192	select HAVE_PATA_PLATFORM
193	select HAVE_PERF_EVENTS
194	select HAVE_PERF_REGS
195	select HAVE_PERF_USER_STACK_DUMP
196	select HAVE_REGS_AND_STACK_ACCESS_API
197	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
198	select HAVE_FUNCTION_ARG_ACCESS_API
199	select MMU_GATHER_RCU_TABLE_FREE
200	select HAVE_RSEQ
201	select HAVE_STACKPROTECTOR
202	select HAVE_SYSCALL_TRACEPOINTS
203	select HAVE_KPROBES
204	select HAVE_KRETPROBES
205	select HAVE_GENERIC_VDSO
206	select IOMMU_DMA if IOMMU_SUPPORT
207	select IRQ_DOMAIN
208	select IRQ_FORCED_THREADING
209	select KASAN_VMALLOC if KASAN_GENERIC
210	select MODULES_USE_ELF_RELA
211	select NEED_DMA_MAP_STATE
212	select NEED_SG_DMA_LENGTH
213	select OF
214	select OF_EARLY_FLATTREE
215	select PCI_DOMAINS_GENERIC if PCI
216	select PCI_ECAM if (ACPI && PCI)
217	select PCI_SYSCALL if PCI
218	select POWER_RESET
219	select POWER_SUPPLY
220	select SPARSE_IRQ
221	select SWIOTLB
222	select SYSCTL_EXCEPTION_TRACE
223	select THREAD_INFO_IN_TASK
224	select HAVE_ARCH_USERFAULTFD_MINOR if USERFAULTFD
225	select TRACE_IRQFLAGS_SUPPORT
226	help
227	  ARM 64-bit (AArch64) Linux support.
228
229config 64BIT
230	def_bool y
231
232config MMU
233	def_bool y
234
235config ARM64_PAGE_SHIFT
236	int
237	default 16 if ARM64_64K_PAGES
238	default 14 if ARM64_16K_PAGES
239	default 12
240
241config ARM64_CONT_PTE_SHIFT
242	int
243	default 5 if ARM64_64K_PAGES
244	default 7 if ARM64_16K_PAGES
245	default 4
246
247config ARM64_CONT_PMD_SHIFT
248	int
249	default 5 if ARM64_64K_PAGES
250	default 5 if ARM64_16K_PAGES
251	default 4
252
253config ARCH_MMAP_RND_BITS_MIN
254       default 14 if ARM64_64K_PAGES
255       default 16 if ARM64_16K_PAGES
256       default 18
257
258# max bits determined by the following formula:
259#  VA_BITS - PAGE_SHIFT - 3
260config ARCH_MMAP_RND_BITS_MAX
261       default 19 if ARM64_VA_BITS=36
262       default 24 if ARM64_VA_BITS=39
263       default 27 if ARM64_VA_BITS=42
264       default 30 if ARM64_VA_BITS=47
265       default 29 if ARM64_VA_BITS=48 && ARM64_64K_PAGES
266       default 31 if ARM64_VA_BITS=48 && ARM64_16K_PAGES
267       default 33 if ARM64_VA_BITS=48
268       default 14 if ARM64_64K_PAGES
269       default 16 if ARM64_16K_PAGES
270       default 18
271
272config ARCH_MMAP_RND_COMPAT_BITS_MIN
273       default 7 if ARM64_64K_PAGES
274       default 9 if ARM64_16K_PAGES
275       default 11
276
277config ARCH_MMAP_RND_COMPAT_BITS_MAX
278       default 16
279
280config NO_IOPORT_MAP
281	def_bool y if !PCI
282
283config STACKTRACE_SUPPORT
284	def_bool y
285
286config ILLEGAL_POINTER_VALUE
287	hex
288	default 0xdead000000000000
289
290config LOCKDEP_SUPPORT
291	def_bool y
292
293config GENERIC_BUG
294	def_bool y
295	depends on BUG
296
297config GENERIC_BUG_RELATIVE_POINTERS
298	def_bool y
299	depends on GENERIC_BUG
300
301config GENERIC_HWEIGHT
302	def_bool y
303
304config GENERIC_CSUM
305        def_bool y
306
307config GENERIC_CALIBRATE_DELAY
308	def_bool y
309
310config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
311	def_bool y
312
313config SMP
314	def_bool y
315
316config KERNEL_MODE_NEON
317	def_bool y
318
319config FIX_EARLYCON_MEM
320	def_bool y
321
322config PGTABLE_LEVELS
323	int
324	default 2 if ARM64_16K_PAGES && ARM64_VA_BITS_36
325	default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42
326	default 3 if ARM64_64K_PAGES && (ARM64_VA_BITS_48 || ARM64_VA_BITS_52)
327	default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39
328	default 3 if ARM64_16K_PAGES && ARM64_VA_BITS_47
329	default 4 if !ARM64_64K_PAGES && ARM64_VA_BITS_48
330
331config ARCH_SUPPORTS_UPROBES
332	def_bool y
333
334config ARCH_PROC_KCORE_TEXT
335	def_bool y
336
337config BROKEN_GAS_INST
338	def_bool !$(as-instr,1:\n.inst 0\n.rept . - 1b\n\nnop\n.endr\n)
339
340config KASAN_SHADOW_OFFSET
341	hex
342	depends on KASAN_GENERIC || KASAN_SW_TAGS
343	default 0xdfff800000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && !KASAN_SW_TAGS
344	default 0xdfffc00000000000 if ARM64_VA_BITS_47 && !KASAN_SW_TAGS
345	default 0xdffffe0000000000 if ARM64_VA_BITS_42 && !KASAN_SW_TAGS
346	default 0xdfffffc000000000 if ARM64_VA_BITS_39 && !KASAN_SW_TAGS
347	default 0xdffffff800000000 if ARM64_VA_BITS_36 && !KASAN_SW_TAGS
348	default 0xefff800000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && KASAN_SW_TAGS
349	default 0xefffc00000000000 if ARM64_VA_BITS_47 && KASAN_SW_TAGS
350	default 0xeffffe0000000000 if ARM64_VA_BITS_42 && KASAN_SW_TAGS
351	default 0xefffffc000000000 if ARM64_VA_BITS_39 && KASAN_SW_TAGS
352	default 0xeffffff800000000 if ARM64_VA_BITS_36 && KASAN_SW_TAGS
353	default 0xffffffffffffffff
354
355source "arch/arm64/Kconfig.platforms"
356
357menu "Kernel Features"
358
359menu "ARM errata workarounds via the alternatives framework"
360
361config ARM64_WORKAROUND_CLEAN_CACHE
362	bool
363
364config ARM64_ERRATUM_826319
365	bool "Cortex-A53: 826319: System might deadlock if a write cannot complete until read data is accepted"
366	default y
367	select ARM64_WORKAROUND_CLEAN_CACHE
368	help
369	  This option adds an alternative code sequence to work around ARM
370	  erratum 826319 on Cortex-A53 parts up to r0p2 with an AMBA 4 ACE or
371	  AXI master interface and an L2 cache.
372
373	  If a Cortex-A53 uses an AMBA AXI4 ACE interface to other processors
374	  and is unable to accept a certain write via this interface, it will
375	  not progress on read data presented on the read data channel and the
376	  system can deadlock.
377
378	  The workaround promotes data cache clean instructions to
379	  data cache clean-and-invalidate.
380	  Please note that this does not necessarily enable the workaround,
381	  as it depends on the alternative framework, which will only patch
382	  the kernel if an affected CPU is detected.
383
384	  If unsure, say Y.
385
386config ARM64_ERRATUM_827319
387	bool "Cortex-A53: 827319: Data cache clean instructions might cause overlapping transactions to the interconnect"
388	default y
389	select ARM64_WORKAROUND_CLEAN_CACHE
390	help
391	  This option adds an alternative code sequence to work around ARM
392	  erratum 827319 on Cortex-A53 parts up to r0p2 with an AMBA 5 CHI
393	  master interface and an L2 cache.
394
395	  Under certain conditions this erratum can cause a clean line eviction
396	  to occur at the same time as another transaction to the same address
397	  on the AMBA 5 CHI interface, which can cause data corruption if the
398	  interconnect reorders the two transactions.
399
400	  The workaround promotes data cache clean instructions to
401	  data cache clean-and-invalidate.
402	  Please note that this does not necessarily enable the workaround,
403	  as it depends on the alternative framework, which will only patch
404	  the kernel if an affected CPU is detected.
405
406	  If unsure, say Y.
407
408config ARM64_ERRATUM_824069
409	bool "Cortex-A53: 824069: Cache line might not be marked as clean after a CleanShared snoop"
410	default y
411	select ARM64_WORKAROUND_CLEAN_CACHE
412	help
413	  This option adds an alternative code sequence to work around ARM
414	  erratum 824069 on Cortex-A53 parts up to r0p2 when it is connected
415	  to a coherent interconnect.
416
417	  If a Cortex-A53 processor is executing a store or prefetch for
418	  write instruction at the same time as a processor in another
419	  cluster is executing a cache maintenance operation to the same
420	  address, then this erratum might cause a clean cache line to be
421	  incorrectly marked as dirty.
422
423	  The workaround promotes data cache clean instructions to
424	  data cache clean-and-invalidate.
425	  Please note that this option does not necessarily enable the
426	  workaround, as it depends on the alternative framework, which will
427	  only patch the kernel if an affected CPU is detected.
428
429	  If unsure, say Y.
430
431config ARM64_ERRATUM_819472
432	bool "Cortex-A53: 819472: Store exclusive instructions might cause data corruption"
433	default y
434	select ARM64_WORKAROUND_CLEAN_CACHE
435	help
436	  This option adds an alternative code sequence to work around ARM
437	  erratum 819472 on Cortex-A53 parts up to r0p1 with an L2 cache
438	  present when it is connected to a coherent interconnect.
439
440	  If the processor is executing a load and store exclusive sequence at
441	  the same time as a processor in another cluster is executing a cache
442	  maintenance operation to the same address, then this erratum might
443	  cause data corruption.
444
445	  The workaround promotes data cache clean instructions to
446	  data cache clean-and-invalidate.
447	  Please note that this does not necessarily enable the workaround,
448	  as it depends on the alternative framework, which will only patch
449	  the kernel if an affected CPU is detected.
450
451	  If unsure, say Y.
452
453config ARM64_ERRATUM_832075
454	bool "Cortex-A57: 832075: possible deadlock on mixing exclusive memory accesses with device loads"
455	default y
456	help
457	  This option adds an alternative code sequence to work around ARM
458	  erratum 832075 on Cortex-A57 parts up to r1p2.
459
460	  Affected Cortex-A57 parts might deadlock when exclusive load/store
461	  instructions to Write-Back memory are mixed with Device loads.
462
463	  The workaround is to promote device loads to use Load-Acquire
464	  semantics.
465	  Please note that this does not necessarily enable the workaround,
466	  as it depends on the alternative framework, which will only patch
467	  the kernel if an affected CPU is detected.
468
469	  If unsure, say Y.
470
471config ARM64_ERRATUM_834220
472	bool "Cortex-A57: 834220: Stage 2 translation fault might be incorrectly reported in presence of a Stage 1 fault"
473	depends on KVM
474	default y
475	help
476	  This option adds an alternative code sequence to work around ARM
477	  erratum 834220 on Cortex-A57 parts up to r1p2.
478
479	  Affected Cortex-A57 parts might report a Stage 2 translation
480	  fault as the result of a Stage 1 fault for load crossing a
481	  page boundary when there is a permission or device memory
482	  alignment fault at Stage 1 and a translation fault at Stage 2.
483
484	  The workaround is to verify that the Stage 1 translation
485	  doesn't generate a fault before handling the Stage 2 fault.
486	  Please note that this does not necessarily enable the workaround,
487	  as it depends on the alternative framework, which will only patch
488	  the kernel if an affected CPU is detected.
489
490	  If unsure, say Y.
491
492config ARM64_ERRATUM_845719
493	bool "Cortex-A53: 845719: a load might read incorrect data"
494	depends on COMPAT
495	default y
496	help
497	  This option adds an alternative code sequence to work around ARM
498	  erratum 845719 on Cortex-A53 parts up to r0p4.
499
500	  When running a compat (AArch32) userspace on an affected Cortex-A53
501	  part, a load at EL0 from a virtual address that matches the bottom 32
502	  bits of the virtual address used by a recent load at (AArch64) EL1
503	  might return incorrect data.
504
505	  The workaround is to write the contextidr_el1 register on exception
506	  return to a 32-bit task.
507	  Please note that this does not necessarily enable the workaround,
508	  as it depends on the alternative framework, which will only patch
509	  the kernel if an affected CPU is detected.
510
511	  If unsure, say Y.
512
513config ARM64_ERRATUM_843419
514	bool "Cortex-A53: 843419: A load or store might access an incorrect address"
515	default y
516	select ARM64_MODULE_PLTS if MODULES
517	help
518	  This option links the kernel with '--fix-cortex-a53-843419' and
519	  enables PLT support to replace certain ADRP instructions, which can
520	  cause subsequent memory accesses to use an incorrect address on
521	  Cortex-A53 parts up to r0p4.
522
523	  If unsure, say Y.
524
525config ARM64_LD_HAS_FIX_ERRATUM_843419
526	def_bool $(ld-option,--fix-cortex-a53-843419)
527
528config ARM64_ERRATUM_1024718
529	bool "Cortex-A55: 1024718: Update of DBM/AP bits without break before make might result in incorrect update"
530	default y
531	help
532	  This option adds a workaround for ARM Cortex-A55 Erratum 1024718.
533
534	  Affected Cortex-A55 cores (all revisions) could cause incorrect
535	  update of the hardware dirty bit when the DBM/AP bits are updated
536	  without a break-before-make. The workaround is to disable the usage
537	  of hardware DBM locally on the affected cores. CPUs not affected by
538	  this erratum will continue to use the feature.
539
540	  If unsure, say Y.
541
542config ARM64_ERRATUM_1418040
543	bool "Cortex-A76/Neoverse-N1: MRC read following MRRC read of specific Generic Timer in AArch32 might give incorrect result"
544	default y
545	depends on COMPAT
546	help
547	  This option adds a workaround for ARM Cortex-A76/Neoverse-N1
548	  errata 1188873 and 1418040.
549
550	  Affected Cortex-A76/Neoverse-N1 cores (r0p0 to r3p1) could
551	  cause register corruption when accessing the timer registers
552	  from AArch32 userspace.
553
554	  If unsure, say Y.
555
556config ARM64_WORKAROUND_SPECULATIVE_AT
557	bool
558
559config ARM64_ERRATUM_1165522
560	bool "Cortex-A76: 1165522: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
561	default y
562	select ARM64_WORKAROUND_SPECULATIVE_AT
563	help
564	  This option adds a workaround for ARM Cortex-A76 erratum 1165522.
565
566	  Affected Cortex-A76 cores (r0p0, r1p0, r2p0) could end-up with
567	  corrupted TLBs by speculating an AT instruction during a guest
568	  context switch.
569
570	  If unsure, say Y.
571
572config ARM64_ERRATUM_1319367
573	bool "Cortex-A57/A72: 1319537: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
574	default y
575	select ARM64_WORKAROUND_SPECULATIVE_AT
576	help
577	  This option adds work arounds for ARM Cortex-A57 erratum 1319537
578	  and A72 erratum 1319367
579
580	  Cortex-A57 and A72 cores could end-up with corrupted TLBs by
581	  speculating an AT instruction during a guest context switch.
582
583	  If unsure, say Y.
584
585config ARM64_ERRATUM_1530923
586	bool "Cortex-A55: 1530923: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
587	default y
588	select ARM64_WORKAROUND_SPECULATIVE_AT
589	help
590	  This option adds a workaround for ARM Cortex-A55 erratum 1530923.
591
592	  Affected Cortex-A55 cores (r0p0, r0p1, r1p0, r2p0) could end-up with
593	  corrupted TLBs by speculating an AT instruction during a guest
594	  context switch.
595
596	  If unsure, say Y.
597
598config ARM64_WORKAROUND_REPEAT_TLBI
599	bool
600
601config ARM64_ERRATUM_1286807
602	bool "Cortex-A76: Modification of the translation table for a virtual address might lead to read-after-read ordering violation"
603	default y
604	select ARM64_WORKAROUND_REPEAT_TLBI
605	help
606	  This option adds a workaround for ARM Cortex-A76 erratum 1286807.
607
608	  On the affected Cortex-A76 cores (r0p0 to r3p0), if a virtual
609	  address for a cacheable mapping of a location is being
610	  accessed by a core while another core is remapping the virtual
611	  address to a new physical page using the recommended
612	  break-before-make sequence, then under very rare circumstances
613	  TLBI+DSB completes before a read using the translation being
614	  invalidated has been observed by other observers. The
615	  workaround repeats the TLBI+DSB operation.
616
617config ARM64_ERRATUM_1463225
618	bool "Cortex-A76: Software Step might prevent interrupt recognition"
619	default y
620	help
621	  This option adds a workaround for Arm Cortex-A76 erratum 1463225.
622
623	  On the affected Cortex-A76 cores (r0p0 to r3p1), software stepping
624	  of a system call instruction (SVC) can prevent recognition of
625	  subsequent interrupts when software stepping is disabled in the
626	  exception handler of the system call and either kernel debugging
627	  is enabled or VHE is in use.
628
629	  Work around the erratum by triggering a dummy step exception
630	  when handling a system call from a task that is being stepped
631	  in a VHE configuration of the kernel.
632
633	  If unsure, say Y.
634
635config ARM64_ERRATUM_1542419
636	bool "Neoverse-N1: workaround mis-ordering of instruction fetches"
637	default y
638	help
639	  This option adds a workaround for ARM Neoverse-N1 erratum
640	  1542419.
641
642	  Affected Neoverse-N1 cores could execute a stale instruction when
643	  modified by another CPU. The workaround depends on a firmware
644	  counterpart.
645
646	  Workaround the issue by hiding the DIC feature from EL0. This
647	  forces user-space to perform cache maintenance.
648
649	  If unsure, say Y.
650
651config ARM64_ERRATUM_1508412
652	bool "Cortex-A77: 1508412: workaround deadlock on sequence of NC/Device load and store exclusive or PAR read"
653	default y
654	help
655	  This option adds a workaround for Arm Cortex-A77 erratum 1508412.
656
657	  Affected Cortex-A77 cores (r0p0, r1p0) could deadlock on a sequence
658	  of a store-exclusive or read of PAR_EL1 and a load with device or
659	  non-cacheable memory attributes. The workaround depends on a firmware
660	  counterpart.
661
662	  KVM guests must also have the workaround implemented or they can
663	  deadlock the system.
664
665	  Work around the issue by inserting DMB SY barriers around PAR_EL1
666	  register reads and warning KVM users. The DMB barrier is sufficient
667	  to prevent a speculative PAR_EL1 read.
668
669	  If unsure, say Y.
670
671config ARM64_WORKAROUND_TRBE_OVERWRITE_FILL_MODE
672	bool
673
674config ARM64_ERRATUM_2119858
675	bool "Cortex-A710: 2119858: workaround TRBE overwriting trace data in FILL mode"
676	default y
677	depends on CORESIGHT_TRBE
678	select ARM64_WORKAROUND_TRBE_OVERWRITE_FILL_MODE
679	help
680	  This option adds the workaround for ARM Cortex-A710 erratum 2119858.
681
682	  Affected Cortex-A710 cores could overwrite up to 3 cache lines of trace
683	  data at the base of the buffer (pointed to by TRBASER_EL1) in FILL mode in
684	  the event of a WRAP event.
685
686	  Work around the issue by always making sure we move the TRBPTR_EL1 by
687	  256 bytes before enabling the buffer and filling the first 256 bytes of
688	  the buffer with ETM ignore packets upon disabling.
689
690	  If unsure, say Y.
691
692config ARM64_ERRATUM_2139208
693	bool "Neoverse-N2: 2139208: workaround TRBE overwriting trace data in FILL mode"
694	default y
695	depends on CORESIGHT_TRBE
696	select ARM64_WORKAROUND_TRBE_OVERWRITE_FILL_MODE
697	help
698	  This option adds the workaround for ARM Neoverse-N2 erratum 2139208.
699
700	  Affected Neoverse-N2 cores could overwrite up to 3 cache lines of trace
701	  data at the base of the buffer (pointed to by TRBASER_EL1) in FILL mode in
702	  the event of a WRAP event.
703
704	  Work around the issue by always making sure we move the TRBPTR_EL1 by
705	  256 bytes before enabling the buffer and filling the first 256 bytes of
706	  the buffer with ETM ignore packets upon disabling.
707
708	  If unsure, say Y.
709
710config ARM64_WORKAROUND_TSB_FLUSH_FAILURE
711	bool
712
713config ARM64_ERRATUM_2054223
714	bool "Cortex-A710: 2054223: workaround TSB instruction failing to flush trace"
715	default y
716	select ARM64_WORKAROUND_TSB_FLUSH_FAILURE
717	help
718	  Enable workaround for ARM Cortex-A710 erratum 2054223
719
720	  Affected cores may fail to flush the trace data on a TSB instruction, when
721	  the PE is in trace prohibited state. This will cause losing a few bytes
722	  of the trace cached.
723
724	  Workaround is to issue two TSB consecutively on affected cores.
725
726	  If unsure, say Y.
727
728config ARM64_ERRATUM_2067961
729	bool "Neoverse-N2: 2067961: workaround TSB instruction failing to flush trace"
730	default y
731	select ARM64_WORKAROUND_TSB_FLUSH_FAILURE
732	help
733	  Enable workaround for ARM Neoverse-N2 erratum 2067961
734
735	  Affected cores may fail to flush the trace data on a TSB instruction, when
736	  the PE is in trace prohibited state. This will cause losing a few bytes
737	  of the trace cached.
738
739	  Workaround is to issue two TSB consecutively on affected cores.
740
741	  If unsure, say Y.
742
743config ARM64_WORKAROUND_TRBE_WRITE_OUT_OF_RANGE
744	bool
745
746config ARM64_ERRATUM_2253138
747	bool "Neoverse-N2: 2253138: workaround TRBE writing to address out-of-range"
748	depends on CORESIGHT_TRBE
749	default y
750	select ARM64_WORKAROUND_TRBE_WRITE_OUT_OF_RANGE
751	help
752	  This option adds the workaround for ARM Neoverse-N2 erratum 2253138.
753
754	  Affected Neoverse-N2 cores might write to an out-of-range address, not reserved
755	  for TRBE. Under some conditions, the TRBE might generate a write to the next
756	  virtually addressed page following the last page of the TRBE address space
757	  (i.e., the TRBLIMITR_EL1.LIMIT), instead of wrapping around to the base.
758
759	  Work around this in the driver by always making sure that there is a
760	  page beyond the TRBLIMITR_EL1.LIMIT, within the space allowed for the TRBE.
761
762	  If unsure, say Y.
763
764config ARM64_ERRATUM_2224489
765	bool "Cortex-A710: 2224489: workaround TRBE writing to address out-of-range"
766	depends on CORESIGHT_TRBE
767	default y
768	select ARM64_WORKAROUND_TRBE_WRITE_OUT_OF_RANGE
769	help
770	  This option adds the workaround for ARM Cortex-A710 erratum 2224489.
771
772	  Affected Cortex-A710 cores might write to an out-of-range address, not reserved
773	  for TRBE. Under some conditions, the TRBE might generate a write to the next
774	  virtually addressed page following the last page of the TRBE address space
775	  (i.e., the TRBLIMITR_EL1.LIMIT), instead of wrapping around to the base.
776
777	  Work around this in the driver by always making sure that there is a
778	  page beyond the TRBLIMITR_EL1.LIMIT, within the space allowed for the TRBE.
779
780	  If unsure, say Y.
781
782config CAVIUM_ERRATUM_22375
783	bool "Cavium erratum 22375, 24313"
784	default y
785	help
786	  Enable workaround for errata 22375 and 24313.
787
788	  This implements two gicv3-its errata workarounds for ThunderX. Both
789	  with a small impact affecting only ITS table allocation.
790
791	    erratum 22375: only alloc 8MB table size
792	    erratum 24313: ignore memory access type
793
794	  The fixes are in ITS initialization and basically ignore memory access
795	  type and table size provided by the TYPER and BASER registers.
796
797	  If unsure, say Y.
798
799config CAVIUM_ERRATUM_23144
800	bool "Cavium erratum 23144: ITS SYNC hang on dual socket system"
801	depends on NUMA
802	default y
803	help
804	  ITS SYNC command hang for cross node io and collections/cpu mapping.
805
806	  If unsure, say Y.
807
808config CAVIUM_ERRATUM_23154
809	bool "Cavium erratum 23154: Access to ICC_IAR1_EL1 is not sync'ed"
810	default y
811	help
812	  The gicv3 of ThunderX requires a modified version for
813	  reading the IAR status to ensure data synchronization
814	  (access to icc_iar1_el1 is not sync'ed before and after).
815
816	  If unsure, say Y.
817
818config CAVIUM_ERRATUM_27456
819	bool "Cavium erratum 27456: Broadcast TLBI instructions may cause icache corruption"
820	default y
821	help
822	  On ThunderX T88 pass 1.x through 2.1 parts, broadcast TLBI
823	  instructions may cause the icache to become corrupted if it
824	  contains data for a non-current ASID.  The fix is to
825	  invalidate the icache when changing the mm context.
826
827	  If unsure, say Y.
828
829config CAVIUM_ERRATUM_30115
830	bool "Cavium erratum 30115: Guest may disable interrupts in host"
831	default y
832	help
833	  On ThunderX T88 pass 1.x through 2.2, T81 pass 1.0 through
834	  1.2, and T83 Pass 1.0, KVM guest execution may disable
835	  interrupts in host. Trapping both GICv3 group-0 and group-1
836	  accesses sidesteps the issue.
837
838	  If unsure, say Y.
839
840config CAVIUM_TX2_ERRATUM_219
841	bool "Cavium ThunderX2 erratum 219: PRFM between TTBR change and ISB fails"
842	default y
843	help
844	  On Cavium ThunderX2, a load, store or prefetch instruction between a
845	  TTBR update and the corresponding context synchronizing operation can
846	  cause a spurious Data Abort to be delivered to any hardware thread in
847	  the CPU core.
848
849	  Work around the issue by avoiding the problematic code sequence and
850	  trapping KVM guest TTBRx_EL1 writes to EL2 when SMT is enabled. The
851	  trap handler performs the corresponding register access, skips the
852	  instruction and ensures context synchronization by virtue of the
853	  exception return.
854
855	  If unsure, say Y.
856
857config FUJITSU_ERRATUM_010001
858	bool "Fujitsu-A64FX erratum E#010001: Undefined fault may occur wrongly"
859	default y
860	help
861	  This option adds a workaround for Fujitsu-A64FX erratum E#010001.
862	  On some variants of the Fujitsu-A64FX cores ver(1.0, 1.1), memory
863	  accesses may cause undefined fault (Data abort, DFSC=0b111111).
864	  This fault occurs under a specific hardware condition when a
865	  load/store instruction performs an address translation using:
866	  case-1  TTBR0_EL1 with TCR_EL1.NFD0 == 1.
867	  case-2  TTBR0_EL2 with TCR_EL2.NFD0 == 1.
868	  case-3  TTBR1_EL1 with TCR_EL1.NFD1 == 1.
869	  case-4  TTBR1_EL2 with TCR_EL2.NFD1 == 1.
870
871	  The workaround is to ensure these bits are clear in TCR_ELx.
872	  The workaround only affects the Fujitsu-A64FX.
873
874	  If unsure, say Y.
875
876config HISILICON_ERRATUM_161600802
877	bool "Hip07 161600802: Erroneous redistributor VLPI base"
878	default y
879	help
880	  The HiSilicon Hip07 SoC uses the wrong redistributor base
881	  when issued ITS commands such as VMOVP and VMAPP, and requires
882	  a 128kB offset to be applied to the target address in this commands.
883
884	  If unsure, say Y.
885
886config QCOM_FALKOR_ERRATUM_1003
887	bool "Falkor E1003: Incorrect translation due to ASID change"
888	default y
889	help
890	  On Falkor v1, an incorrect ASID may be cached in the TLB when ASID
891	  and BADDR are changed together in TTBRx_EL1. Since we keep the ASID
892	  in TTBR1_EL1, this situation only occurs in the entry trampoline and
893	  then only for entries in the walk cache, since the leaf translation
894	  is unchanged. Work around the erratum by invalidating the walk cache
895	  entries for the trampoline before entering the kernel proper.
896
897config QCOM_FALKOR_ERRATUM_1009
898	bool "Falkor E1009: Prematurely complete a DSB after a TLBI"
899	default y
900	select ARM64_WORKAROUND_REPEAT_TLBI
901	help
902	  On Falkor v1, the CPU may prematurely complete a DSB following a
903	  TLBI xxIS invalidate maintenance operation. Repeat the TLBI operation
904	  one more time to fix the issue.
905
906	  If unsure, say Y.
907
908config QCOM_QDF2400_ERRATUM_0065
909	bool "QDF2400 E0065: Incorrect GITS_TYPER.ITT_Entry_size"
910	default y
911	help
912	  On Qualcomm Datacenter Technologies QDF2400 SoC, ITS hardware reports
913	  ITE size incorrectly. The GITS_TYPER.ITT_Entry_size field should have
914	  been indicated as 16Bytes (0xf), not 8Bytes (0x7).
915
916	  If unsure, say Y.
917
918config QCOM_FALKOR_ERRATUM_E1041
919	bool "Falkor E1041: Speculative instruction fetches might cause errant memory access"
920	default y
921	help
922	  Falkor CPU may speculatively fetch instructions from an improper
923	  memory location when MMU translation is changed from SCTLR_ELn[M]=1
924	  to SCTLR_ELn[M]=0. Prefix an ISB instruction to fix the problem.
925
926	  If unsure, say Y.
927
928config NVIDIA_CARMEL_CNP_ERRATUM
929	bool "NVIDIA Carmel CNP: CNP on Carmel semantically different than ARM cores"
930	default y
931	help
932	  If CNP is enabled on Carmel cores, non-sharable TLBIs on a core will not
933	  invalidate shared TLB entries installed by a different core, as it would
934	  on standard ARM cores.
935
936	  If unsure, say Y.
937
938config SOCIONEXT_SYNQUACER_PREITS
939	bool "Socionext Synquacer: Workaround for GICv3 pre-ITS"
940	default y
941	help
942	  Socionext Synquacer SoCs implement a separate h/w block to generate
943	  MSI doorbell writes with non-zero values for the device ID.
944
945	  If unsure, say Y.
946
947endmenu
948
949
950choice
951	prompt "Page size"
952	default ARM64_4K_PAGES
953	help
954	  Page size (translation granule) configuration.
955
956config ARM64_4K_PAGES
957	bool "4KB"
958	help
959	  This feature enables 4KB pages support.
960
961config ARM64_16K_PAGES
962	bool "16KB"
963	help
964	  The system will use 16KB pages support. AArch32 emulation
965	  requires applications compiled with 16K (or a multiple of 16K)
966	  aligned segments.
967
968config ARM64_64K_PAGES
969	bool "64KB"
970	help
971	  This feature enables 64KB pages support (4KB by default)
972	  allowing only two levels of page tables and faster TLB
973	  look-up. AArch32 emulation requires applications compiled
974	  with 64K aligned segments.
975
976endchoice
977
978choice
979	prompt "Virtual address space size"
980	default ARM64_VA_BITS_39 if ARM64_4K_PAGES
981	default ARM64_VA_BITS_47 if ARM64_16K_PAGES
982	default ARM64_VA_BITS_42 if ARM64_64K_PAGES
983	help
984	  Allows choosing one of multiple possible virtual address
985	  space sizes. The level of translation table is determined by
986	  a combination of page size and virtual address space size.
987
988config ARM64_VA_BITS_36
989	bool "36-bit" if EXPERT
990	depends on ARM64_16K_PAGES
991
992config ARM64_VA_BITS_39
993	bool "39-bit"
994	depends on ARM64_4K_PAGES
995
996config ARM64_VA_BITS_42
997	bool "42-bit"
998	depends on ARM64_64K_PAGES
999
1000config ARM64_VA_BITS_47
1001	bool "47-bit"
1002	depends on ARM64_16K_PAGES
1003
1004config ARM64_VA_BITS_48
1005	bool "48-bit"
1006
1007config ARM64_VA_BITS_52
1008	bool "52-bit"
1009	depends on ARM64_64K_PAGES && (ARM64_PAN || !ARM64_SW_TTBR0_PAN)
1010	help
1011	  Enable 52-bit virtual addressing for userspace when explicitly
1012	  requested via a hint to mmap(). The kernel will also use 52-bit
1013	  virtual addresses for its own mappings (provided HW support for
1014	  this feature is available, otherwise it reverts to 48-bit).
1015
1016	  NOTE: Enabling 52-bit virtual addressing in conjunction with
1017	  ARMv8.3 Pointer Authentication will result in the PAC being
1018	  reduced from 7 bits to 3 bits, which may have a significant
1019	  impact on its susceptibility to brute-force attacks.
1020
1021	  If unsure, select 48-bit virtual addressing instead.
1022
1023endchoice
1024
1025config ARM64_FORCE_52BIT
1026	bool "Force 52-bit virtual addresses for userspace"
1027	depends on ARM64_VA_BITS_52 && EXPERT
1028	help
1029	  For systems with 52-bit userspace VAs enabled, the kernel will attempt
1030	  to maintain compatibility with older software by providing 48-bit VAs
1031	  unless a hint is supplied to mmap.
1032
1033	  This configuration option disables the 48-bit compatibility logic, and
1034	  forces all userspace addresses to be 52-bit on HW that supports it. One
1035	  should only enable this configuration option for stress testing userspace
1036	  memory management code. If unsure say N here.
1037
1038config ARM64_VA_BITS
1039	int
1040	default 36 if ARM64_VA_BITS_36
1041	default 39 if ARM64_VA_BITS_39
1042	default 42 if ARM64_VA_BITS_42
1043	default 47 if ARM64_VA_BITS_47
1044	default 48 if ARM64_VA_BITS_48
1045	default 52 if ARM64_VA_BITS_52
1046
1047choice
1048	prompt "Physical address space size"
1049	default ARM64_PA_BITS_48
1050	help
1051	  Choose the maximum physical address range that the kernel will
1052	  support.
1053
1054config ARM64_PA_BITS_48
1055	bool "48-bit"
1056
1057config ARM64_PA_BITS_52
1058	bool "52-bit (ARMv8.2)"
1059	depends on ARM64_64K_PAGES
1060	depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
1061	help
1062	  Enable support for a 52-bit physical address space, introduced as
1063	  part of the ARMv8.2-LPA extension.
1064
1065	  With this enabled, the kernel will also continue to work on CPUs that
1066	  do not support ARMv8.2-LPA, but with some added memory overhead (and
1067	  minor performance overhead).
1068
1069endchoice
1070
1071config ARM64_PA_BITS
1072	int
1073	default 48 if ARM64_PA_BITS_48
1074	default 52 if ARM64_PA_BITS_52
1075
1076choice
1077	prompt "Endianness"
1078	default CPU_LITTLE_ENDIAN
1079	help
1080	  Select the endianness of data accesses performed by the CPU. Userspace
1081	  applications will need to be compiled and linked for the endianness
1082	  that is selected here.
1083
1084config CPU_BIG_ENDIAN
1085	bool "Build big-endian kernel"
1086	depends on !LD_IS_LLD || LLD_VERSION >= 130000
1087	help
1088	  Say Y if you plan on running a kernel with a big-endian userspace.
1089
1090config CPU_LITTLE_ENDIAN
1091	bool "Build little-endian kernel"
1092	help
1093	  Say Y if you plan on running a kernel with a little-endian userspace.
1094	  This is usually the case for distributions targeting arm64.
1095
1096endchoice
1097
1098config SCHED_MC
1099	bool "Multi-core scheduler support"
1100	help
1101	  Multi-core scheduler support improves the CPU scheduler's decision
1102	  making when dealing with multi-core CPU chips at a cost of slightly
1103	  increased overhead in some places. If unsure say N here.
1104
1105config SCHED_CLUSTER
1106	bool "Cluster scheduler support"
1107	help
1108	  Cluster scheduler support improves the CPU scheduler's decision
1109	  making when dealing with machines that have clusters of CPUs.
1110	  Cluster usually means a couple of CPUs which are placed closely
1111	  by sharing mid-level caches, last-level cache tags or internal
1112	  busses.
1113
1114config SCHED_SMT
1115	bool "SMT scheduler support"
1116	help
1117	  Improves the CPU scheduler's decision making when dealing with
1118	  MultiThreading at a cost of slightly increased overhead in some
1119	  places. If unsure say N here.
1120
1121config NR_CPUS
1122	int "Maximum number of CPUs (2-4096)"
1123	range 2 4096
1124	default "256"
1125
1126config HOTPLUG_CPU
1127	bool "Support for hot-pluggable CPUs"
1128	select GENERIC_IRQ_MIGRATION
1129	help
1130	  Say Y here to experiment with turning CPUs off and on.  CPUs
1131	  can be controlled through /sys/devices/system/cpu.
1132
1133# Common NUMA Features
1134config NUMA
1135	bool "NUMA Memory Allocation and Scheduler Support"
1136	select GENERIC_ARCH_NUMA
1137	select ACPI_NUMA if ACPI
1138	select OF_NUMA
1139	select HAVE_SETUP_PER_CPU_AREA
1140	select NEED_PER_CPU_EMBED_FIRST_CHUNK
1141	select NEED_PER_CPU_PAGE_FIRST_CHUNK
1142	select USE_PERCPU_NUMA_NODE_ID
1143	help
1144	  Enable NUMA (Non-Uniform Memory Access) support.
1145
1146	  The kernel will try to allocate memory used by a CPU on the
1147	  local memory of the CPU and add some more
1148	  NUMA awareness to the kernel.
1149
1150config NODES_SHIFT
1151	int "Maximum NUMA Nodes (as a power of 2)"
1152	range 1 10
1153	default "4"
1154	depends on NUMA
1155	help
1156	  Specify the maximum number of NUMA Nodes available on the target
1157	  system.  Increases memory reserved to accommodate various tables.
1158
1159source "kernel/Kconfig.hz"
1160
1161config ARCH_SPARSEMEM_ENABLE
1162	def_bool y
1163	select SPARSEMEM_VMEMMAP_ENABLE
1164	select SPARSEMEM_VMEMMAP
1165
1166config HW_PERF_EVENTS
1167	def_bool y
1168	depends on ARM_PMU
1169
1170config ARCH_HAS_FILTER_PGPROT
1171	def_bool y
1172
1173# Supported by clang >= 7.0
1174config CC_HAVE_SHADOW_CALL_STACK
1175	def_bool $(cc-option, -fsanitize=shadow-call-stack -ffixed-x18)
1176
1177config PARAVIRT
1178	bool "Enable paravirtualization code"
1179	help
1180	  This changes the kernel so it can modify itself when it is run
1181	  under a hypervisor, potentially improving performance significantly
1182	  over full virtualization.
1183
1184config PARAVIRT_TIME_ACCOUNTING
1185	bool "Paravirtual steal time accounting"
1186	select PARAVIRT
1187	help
1188	  Select this option to enable fine granularity task steal time
1189	  accounting. Time spent executing other tasks in parallel with
1190	  the current vCPU is discounted from the vCPU power. To account for
1191	  that, there can be a small performance impact.
1192
1193	  If in doubt, say N here.
1194
1195config KEXEC
1196	depends on PM_SLEEP_SMP
1197	select KEXEC_CORE
1198	bool "kexec system call"
1199	help
1200	  kexec is a system call that implements the ability to shutdown your
1201	  current kernel, and to start another kernel.  It is like a reboot
1202	  but it is independent of the system firmware.   And like a reboot
1203	  you can start any kernel with it, not just Linux.
1204
1205config KEXEC_FILE
1206	bool "kexec file based system call"
1207	select KEXEC_CORE
1208	select HAVE_IMA_KEXEC if IMA
1209	help
1210	  This is new version of kexec system call. This system call is
1211	  file based and takes file descriptors as system call argument
1212	  for kernel and initramfs as opposed to list of segments as
1213	  accepted by previous system call.
1214
1215config KEXEC_SIG
1216	bool "Verify kernel signature during kexec_file_load() syscall"
1217	depends on KEXEC_FILE
1218	help
1219	  Select this option to verify a signature with loaded kernel
1220	  image. If configured, any attempt of loading a image without
1221	  valid signature will fail.
1222
1223	  In addition to that option, you need to enable signature
1224	  verification for the corresponding kernel image type being
1225	  loaded in order for this to work.
1226
1227config KEXEC_IMAGE_VERIFY_SIG
1228	bool "Enable Image signature verification support"
1229	default y
1230	depends on KEXEC_SIG
1231	depends on EFI && SIGNED_PE_FILE_VERIFICATION
1232	help
1233	  Enable Image signature verification support.
1234
1235comment "Support for PE file signature verification disabled"
1236	depends on KEXEC_SIG
1237	depends on !EFI || !SIGNED_PE_FILE_VERIFICATION
1238
1239config CRASH_DUMP
1240	bool "Build kdump crash kernel"
1241	help
1242	  Generate crash dump after being started by kexec. This should
1243	  be normally only set in special crash dump kernels which are
1244	  loaded in the main kernel with kexec-tools into a specially
1245	  reserved region and then later executed after a crash by
1246	  kdump/kexec.
1247
1248	  For more details see Documentation/admin-guide/kdump/kdump.rst
1249
1250config TRANS_TABLE
1251	def_bool y
1252	depends on HIBERNATION || KEXEC_CORE
1253
1254config XEN_DOM0
1255	def_bool y
1256	depends on XEN
1257
1258config XEN
1259	bool "Xen guest support on ARM64"
1260	depends on ARM64 && OF
1261	select SWIOTLB_XEN
1262	select PARAVIRT
1263	help
1264	  Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64.
1265
1266config FORCE_MAX_ZONEORDER
1267	int
1268	default "14" if ARM64_64K_PAGES
1269	default "12" if ARM64_16K_PAGES
1270	default "11"
1271	help
1272	  The kernel memory allocator divides physically contiguous memory
1273	  blocks into "zones", where each zone is a power of two number of
1274	  pages.  This option selects the largest power of two that the kernel
1275	  keeps in the memory allocator.  If you need to allocate very large
1276	  blocks of physically contiguous memory, then you may need to
1277	  increase this value.
1278
1279	  This config option is actually maximum order plus one. For example,
1280	  a value of 11 means that the largest free memory block is 2^10 pages.
1281
1282	  We make sure that we can allocate upto a HugePage size for each configuration.
1283	  Hence we have :
1284		MAX_ORDER = (PMD_SHIFT - PAGE_SHIFT) + 1 => PAGE_SHIFT - 2
1285
1286	  However for 4K, we choose a higher default value, 11 as opposed to 10, giving us
1287	  4M allocations matching the default size used by generic code.
1288
1289config UNMAP_KERNEL_AT_EL0
1290	bool "Unmap kernel when running in userspace (aka \"KAISER\")" if EXPERT
1291	default y
1292	help
1293	  Speculation attacks against some high-performance processors can
1294	  be used to bypass MMU permission checks and leak kernel data to
1295	  userspace. This can be defended against by unmapping the kernel
1296	  when running in userspace, mapping it back in on exception entry
1297	  via a trampoline page in the vector table.
1298
1299	  If unsure, say Y.
1300
1301config RODATA_FULL_DEFAULT_ENABLED
1302	bool "Apply r/o permissions of VM areas also to their linear aliases"
1303	default y
1304	help
1305	  Apply read-only attributes of VM areas to the linear alias of
1306	  the backing pages as well. This prevents code or read-only data
1307	  from being modified (inadvertently or intentionally) via another
1308	  mapping of the same memory page. This additional enhancement can
1309	  be turned off at runtime by passing rodata=[off|on] (and turned on
1310	  with rodata=full if this option is set to 'n')
1311
1312	  This requires the linear region to be mapped down to pages,
1313	  which may adversely affect performance in some cases.
1314
1315config ARM64_SW_TTBR0_PAN
1316	bool "Emulate Privileged Access Never using TTBR0_EL1 switching"
1317	help
1318	  Enabling this option prevents the kernel from accessing
1319	  user-space memory directly by pointing TTBR0_EL1 to a reserved
1320	  zeroed area and reserved ASID. The user access routines
1321	  restore the valid TTBR0_EL1 temporarily.
1322
1323config ARM64_TAGGED_ADDR_ABI
1324	bool "Enable the tagged user addresses syscall ABI"
1325	default y
1326	help
1327	  When this option is enabled, user applications can opt in to a
1328	  relaxed ABI via prctl() allowing tagged addresses to be passed
1329	  to system calls as pointer arguments. For details, see
1330	  Documentation/arm64/tagged-address-abi.rst.
1331
1332menuconfig COMPAT
1333	bool "Kernel support for 32-bit EL0"
1334	depends on ARM64_4K_PAGES || EXPERT
1335	select HAVE_UID16
1336	select OLD_SIGSUSPEND3
1337	select COMPAT_OLD_SIGACTION
1338	help
1339	  This option enables support for a 32-bit EL0 running under a 64-bit
1340	  kernel at EL1. AArch32-specific components such as system calls,
1341	  the user helper functions, VFP support and the ptrace interface are
1342	  handled appropriately by the kernel.
1343
1344	  If you use a page size other than 4KB (i.e, 16KB or 64KB), please be aware
1345	  that you will only be able to execute AArch32 binaries that were compiled
1346	  with page size aligned segments.
1347
1348	  If you want to execute 32-bit userspace applications, say Y.
1349
1350if COMPAT
1351
1352config KUSER_HELPERS
1353	bool "Enable kuser helpers page for 32-bit applications"
1354	default y
1355	help
1356	  Warning: disabling this option may break 32-bit user programs.
1357
1358	  Provide kuser helpers to compat tasks. The kernel provides
1359	  helper code to userspace in read only form at a fixed location
1360	  to allow userspace to be independent of the CPU type fitted to
1361	  the system. This permits binaries to be run on ARMv4 through
1362	  to ARMv8 without modification.
1363
1364	  See Documentation/arm/kernel_user_helpers.rst for details.
1365
1366	  However, the fixed address nature of these helpers can be used
1367	  by ROP (return orientated programming) authors when creating
1368	  exploits.
1369
1370	  If all of the binaries and libraries which run on your platform
1371	  are built specifically for your platform, and make no use of
1372	  these helpers, then you can turn this option off to hinder
1373	  such exploits. However, in that case, if a binary or library
1374	  relying on those helpers is run, it will not function correctly.
1375
1376	  Say N here only if you are absolutely certain that you do not
1377	  need these helpers; otherwise, the safe option is to say Y.
1378
1379config COMPAT_VDSO
1380	bool "Enable vDSO for 32-bit applications"
1381	depends on !CPU_BIG_ENDIAN
1382	depends on (CC_IS_CLANG && LD_IS_LLD) || "$(CROSS_COMPILE_COMPAT)" != ""
1383	select GENERIC_COMPAT_VDSO
1384	default y
1385	help
1386	  Place in the process address space of 32-bit applications an
1387	  ELF shared object providing fast implementations of gettimeofday
1388	  and clock_gettime.
1389
1390	  You must have a 32-bit build of glibc 2.22 or later for programs
1391	  to seamlessly take advantage of this.
1392
1393config THUMB2_COMPAT_VDSO
1394	bool "Compile the 32-bit vDSO for Thumb-2 mode" if EXPERT
1395	depends on COMPAT_VDSO
1396	default y
1397	help
1398	  Compile the compat vDSO with '-mthumb -fomit-frame-pointer' if y,
1399	  otherwise with '-marm'.
1400
1401menuconfig ARMV8_DEPRECATED
1402	bool "Emulate deprecated/obsolete ARMv8 instructions"
1403	depends on SYSCTL
1404	help
1405	  Legacy software support may require certain instructions
1406	  that have been deprecated or obsoleted in the architecture.
1407
1408	  Enable this config to enable selective emulation of these
1409	  features.
1410
1411	  If unsure, say Y
1412
1413if ARMV8_DEPRECATED
1414
1415config SWP_EMULATION
1416	bool "Emulate SWP/SWPB instructions"
1417	help
1418	  ARMv8 obsoletes the use of A32 SWP/SWPB instructions such that
1419	  they are always undefined. Say Y here to enable software
1420	  emulation of these instructions for userspace using LDXR/STXR.
1421	  This feature can be controlled at runtime with the abi.swp
1422	  sysctl which is disabled by default.
1423
1424	  In some older versions of glibc [<=2.8] SWP is used during futex
1425	  trylock() operations with the assumption that the code will not
1426	  be preempted. This invalid assumption may be more likely to fail
1427	  with SWP emulation enabled, leading to deadlock of the user
1428	  application.
1429
1430	  NOTE: when accessing uncached shared regions, LDXR/STXR rely
1431	  on an external transaction monitoring block called a global
1432	  monitor to maintain update atomicity. If your system does not
1433	  implement a global monitor, this option can cause programs that
1434	  perform SWP operations to uncached memory to deadlock.
1435
1436	  If unsure, say Y
1437
1438config CP15_BARRIER_EMULATION
1439	bool "Emulate CP15 Barrier instructions"
1440	help
1441	  The CP15 barrier instructions - CP15ISB, CP15DSB, and
1442	  CP15DMB - are deprecated in ARMv8 (and ARMv7). It is
1443	  strongly recommended to use the ISB, DSB, and DMB
1444	  instructions instead.
1445
1446	  Say Y here to enable software emulation of these
1447	  instructions for AArch32 userspace code. When this option is
1448	  enabled, CP15 barrier usage is traced which can help
1449	  identify software that needs updating. This feature can be
1450	  controlled at runtime with the abi.cp15_barrier sysctl.
1451
1452	  If unsure, say Y
1453
1454config SETEND_EMULATION
1455	bool "Emulate SETEND instruction"
1456	help
1457	  The SETEND instruction alters the data-endianness of the
1458	  AArch32 EL0, and is deprecated in ARMv8.
1459
1460	  Say Y here to enable software emulation of the instruction
1461	  for AArch32 userspace code. This feature can be controlled
1462	  at runtime with the abi.setend sysctl.
1463
1464	  Note: All the cpus on the system must have mixed endian support at EL0
1465	  for this feature to be enabled. If a new CPU - which doesn't support mixed
1466	  endian - is hotplugged in after this feature has been enabled, there could
1467	  be unexpected results in the applications.
1468
1469	  If unsure, say Y
1470endif
1471
1472endif
1473
1474menu "ARMv8.1 architectural features"
1475
1476config ARM64_HW_AFDBM
1477	bool "Support for hardware updates of the Access and Dirty page flags"
1478	default y
1479	help
1480	  The ARMv8.1 architecture extensions introduce support for
1481	  hardware updates of the access and dirty information in page
1482	  table entries. When enabled in TCR_EL1 (HA and HD bits) on
1483	  capable processors, accesses to pages with PTE_AF cleared will
1484	  set this bit instead of raising an access flag fault.
1485	  Similarly, writes to read-only pages with the DBM bit set will
1486	  clear the read-only bit (AP[2]) instead of raising a
1487	  permission fault.
1488
1489	  Kernels built with this configuration option enabled continue
1490	  to work on pre-ARMv8.1 hardware and the performance impact is
1491	  minimal. If unsure, say Y.
1492
1493config ARM64_PAN
1494	bool "Enable support for Privileged Access Never (PAN)"
1495	default y
1496	help
1497	 Privileged Access Never (PAN; part of the ARMv8.1 Extensions)
1498	 prevents the kernel or hypervisor from accessing user-space (EL0)
1499	 memory directly.
1500
1501	 Choosing this option will cause any unprotected (not using
1502	 copy_to_user et al) memory access to fail with a permission fault.
1503
1504	 The feature is detected at runtime, and will remain as a 'nop'
1505	 instruction if the cpu does not implement the feature.
1506
1507config AS_HAS_LDAPR
1508	def_bool $(as-instr,.arch_extension rcpc)
1509
1510config AS_HAS_LSE_ATOMICS
1511	def_bool $(as-instr,.arch_extension lse)
1512
1513config ARM64_LSE_ATOMICS
1514	bool
1515	default ARM64_USE_LSE_ATOMICS
1516	depends on AS_HAS_LSE_ATOMICS
1517
1518config ARM64_USE_LSE_ATOMICS
1519	bool "Atomic instructions"
1520	depends on JUMP_LABEL
1521	default y
1522	help
1523	  As part of the Large System Extensions, ARMv8.1 introduces new
1524	  atomic instructions that are designed specifically to scale in
1525	  very large systems.
1526
1527	  Say Y here to make use of these instructions for the in-kernel
1528	  atomic routines. This incurs a small overhead on CPUs that do
1529	  not support these instructions and requires the kernel to be
1530	  built with binutils >= 2.25 in order for the new instructions
1531	  to be used.
1532
1533endmenu
1534
1535menu "ARMv8.2 architectural features"
1536
1537config AS_HAS_ARMV8_2
1538       def_bool $(cc-option,-Wa$(comma)-march=armv8.2-a)
1539
1540config AS_HAS_SHA3
1541       def_bool $(as-instr,.arch armv8.2-a+sha3)
1542
1543config ARM64_PMEM
1544	bool "Enable support for persistent memory"
1545	select ARCH_HAS_PMEM_API
1546	select ARCH_HAS_UACCESS_FLUSHCACHE
1547	help
1548	  Say Y to enable support for the persistent memory API based on the
1549	  ARMv8.2 DCPoP feature.
1550
1551	  The feature is detected at runtime, and the kernel will use DC CVAC
1552	  operations if DC CVAP is not supported (following the behaviour of
1553	  DC CVAP itself if the system does not define a point of persistence).
1554
1555config ARM64_RAS_EXTN
1556	bool "Enable support for RAS CPU Extensions"
1557	default y
1558	help
1559	  CPUs that support the Reliability, Availability and Serviceability
1560	  (RAS) Extensions, part of ARMv8.2 are able to track faults and
1561	  errors, classify them and report them to software.
1562
1563	  On CPUs with these extensions system software can use additional
1564	  barriers to determine if faults are pending and read the
1565	  classification from a new set of registers.
1566
1567	  Selecting this feature will allow the kernel to use these barriers
1568	  and access the new registers if the system supports the extension.
1569	  Platform RAS features may additionally depend on firmware support.
1570
1571config ARM64_CNP
1572	bool "Enable support for Common Not Private (CNP) translations"
1573	default y
1574	depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
1575	help
1576	  Common Not Private (CNP) allows translation table entries to
1577	  be shared between different PEs in the same inner shareable
1578	  domain, so the hardware can use this fact to optimise the
1579	  caching of such entries in the TLB.
1580
1581	  Selecting this option allows the CNP feature to be detected
1582	  at runtime, and does not affect PEs that do not implement
1583	  this feature.
1584
1585endmenu
1586
1587menu "ARMv8.3 architectural features"
1588
1589config ARM64_PTR_AUTH
1590	bool "Enable support for pointer authentication"
1591	default y
1592	help
1593	  Pointer authentication (part of the ARMv8.3 Extensions) provides
1594	  instructions for signing and authenticating pointers against secret
1595	  keys, which can be used to mitigate Return Oriented Programming (ROP)
1596	  and other attacks.
1597
1598	  This option enables these instructions at EL0 (i.e. for userspace).
1599	  Choosing this option will cause the kernel to initialise secret keys
1600	  for each process at exec() time, with these keys being
1601	  context-switched along with the process.
1602
1603	  The feature is detected at runtime. If the feature is not present in
1604	  hardware it will not be advertised to userspace/KVM guest nor will it
1605	  be enabled.
1606
1607	  If the feature is present on the boot CPU but not on a late CPU, then
1608	  the late CPU will be parked. Also, if the boot CPU does not have
1609	  address auth and the late CPU has then the late CPU will still boot
1610	  but with the feature disabled. On such a system, this option should
1611	  not be selected.
1612
1613config ARM64_PTR_AUTH_KERNEL
1614	bool "Use pointer authentication for kernel"
1615	default y
1616	depends on ARM64_PTR_AUTH
1617	depends on (CC_HAS_SIGN_RETURN_ADDRESS || CC_HAS_BRANCH_PROT_PAC_RET) && AS_HAS_PAC
1618	# Modern compilers insert a .note.gnu.property section note for PAC
1619	# which is only understood by binutils starting with version 2.33.1.
1620	depends on LD_IS_LLD || LD_VERSION >= 23301 || (CC_IS_GCC && GCC_VERSION < 90100)
1621	depends on !CC_IS_CLANG || AS_HAS_CFI_NEGATE_RA_STATE
1622	depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_REGS)
1623	help
1624	  If the compiler supports the -mbranch-protection or
1625	  -msign-return-address flag (e.g. GCC 7 or later), then this option
1626	  will cause the kernel itself to be compiled with return address
1627	  protection. In this case, and if the target hardware is known to
1628	  support pointer authentication, then CONFIG_STACKPROTECTOR can be
1629	  disabled with minimal loss of protection.
1630
1631	  This feature works with FUNCTION_GRAPH_TRACER option only if
1632	  DYNAMIC_FTRACE_WITH_REGS is enabled.
1633
1634config CC_HAS_BRANCH_PROT_PAC_RET
1635	# GCC 9 or later, clang 8 or later
1636	def_bool $(cc-option,-mbranch-protection=pac-ret+leaf)
1637
1638config CC_HAS_SIGN_RETURN_ADDRESS
1639	# GCC 7, 8
1640	def_bool $(cc-option,-msign-return-address=all)
1641
1642config AS_HAS_PAC
1643	def_bool $(cc-option,-Wa$(comma)-march=armv8.3-a)
1644
1645config AS_HAS_CFI_NEGATE_RA_STATE
1646	def_bool $(as-instr,.cfi_startproc\n.cfi_negate_ra_state\n.cfi_endproc\n)
1647
1648endmenu
1649
1650menu "ARMv8.4 architectural features"
1651
1652config ARM64_AMU_EXTN
1653	bool "Enable support for the Activity Monitors Unit CPU extension"
1654	default y
1655	help
1656	  The activity monitors extension is an optional extension introduced
1657	  by the ARMv8.4 CPU architecture. This enables support for version 1
1658	  of the activity monitors architecture, AMUv1.
1659
1660	  To enable the use of this extension on CPUs that implement it, say Y.
1661
1662	  Note that for architectural reasons, firmware _must_ implement AMU
1663	  support when running on CPUs that present the activity monitors
1664	  extension. The required support is present in:
1665	    * Version 1.5 and later of the ARM Trusted Firmware
1666
1667	  For kernels that have this configuration enabled but boot with broken
1668	  firmware, you may need to say N here until the firmware is fixed.
1669	  Otherwise you may experience firmware panics or lockups when
1670	  accessing the counter registers. Even if you are not observing these
1671	  symptoms, the values returned by the register reads might not
1672	  correctly reflect reality. Most commonly, the value read will be 0,
1673	  indicating that the counter is not enabled.
1674
1675config AS_HAS_ARMV8_4
1676	def_bool $(cc-option,-Wa$(comma)-march=armv8.4-a)
1677
1678config ARM64_TLB_RANGE
1679	bool "Enable support for tlbi range feature"
1680	default y
1681	depends on AS_HAS_ARMV8_4
1682	help
1683	  ARMv8.4-TLBI provides TLBI invalidation instruction that apply to a
1684	  range of input addresses.
1685
1686	  The feature introduces new assembly instructions, and they were
1687	  support when binutils >= 2.30.
1688
1689endmenu
1690
1691menu "ARMv8.5 architectural features"
1692
1693config AS_HAS_ARMV8_5
1694	def_bool $(cc-option,-Wa$(comma)-march=armv8.5-a)
1695
1696config ARM64_BTI
1697	bool "Branch Target Identification support"
1698	default y
1699	help
1700	  Branch Target Identification (part of the ARMv8.5 Extensions)
1701	  provides a mechanism to limit the set of locations to which computed
1702	  branch instructions such as BR or BLR can jump.
1703
1704	  To make use of BTI on CPUs that support it, say Y.
1705
1706	  BTI is intended to provide complementary protection to other control
1707	  flow integrity protection mechanisms, such as the Pointer
1708	  authentication mechanism provided as part of the ARMv8.3 Extensions.
1709	  For this reason, it does not make sense to enable this option without
1710	  also enabling support for pointer authentication.  Thus, when
1711	  enabling this option you should also select ARM64_PTR_AUTH=y.
1712
1713	  Userspace binaries must also be specifically compiled to make use of
1714	  this mechanism.  If you say N here or the hardware does not support
1715	  BTI, such binaries can still run, but you get no additional
1716	  enforcement of branch destinations.
1717
1718config ARM64_BTI_KERNEL
1719	bool "Use Branch Target Identification for kernel"
1720	default y
1721	depends on ARM64_BTI
1722	depends on ARM64_PTR_AUTH_KERNEL
1723	depends on CC_HAS_BRANCH_PROT_PAC_RET_BTI
1724	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94697
1725	depends on !CC_IS_GCC || GCC_VERSION >= 100100
1726	# https://github.com/llvm/llvm-project/commit/a88c722e687e6780dcd6a58718350dc76fcc4cc9
1727	depends on !CC_IS_CLANG || CLANG_VERSION >= 120000
1728	depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_REGS)
1729	help
1730	  Build the kernel with Branch Target Identification annotations
1731	  and enable enforcement of this for kernel code. When this option
1732	  is enabled and the system supports BTI all kernel code including
1733	  modular code must have BTI enabled.
1734
1735config CC_HAS_BRANCH_PROT_PAC_RET_BTI
1736	# GCC 9 or later, clang 8 or later
1737	def_bool $(cc-option,-mbranch-protection=pac-ret+leaf+bti)
1738
1739config ARM64_E0PD
1740	bool "Enable support for E0PD"
1741	default y
1742	help
1743	  E0PD (part of the ARMv8.5 extensions) allows us to ensure
1744	  that EL0 accesses made via TTBR1 always fault in constant time,
1745	  providing similar benefits to KASLR as those provided by KPTI, but
1746	  with lower overhead and without disrupting legitimate access to
1747	  kernel memory such as SPE.
1748
1749	  This option enables E0PD for TTBR1 where available.
1750
1751config ARCH_RANDOM
1752	bool "Enable support for random number generation"
1753	default y
1754	help
1755	  Random number generation (part of the ARMv8.5 Extensions)
1756	  provides a high bandwidth, cryptographically secure
1757	  hardware random number generator.
1758
1759config ARM64_AS_HAS_MTE
1760	# Initial support for MTE went in binutils 2.32.0, checked with
1761	# ".arch armv8.5-a+memtag" below. However, this was incomplete
1762	# as a late addition to the final architecture spec (LDGM/STGM)
1763	# is only supported in the newer 2.32.x and 2.33 binutils
1764	# versions, hence the extra "stgm" instruction check below.
1765	def_bool $(as-instr,.arch armv8.5-a+memtag\nstgm xzr$(comma)[x0])
1766
1767config ARM64_MTE
1768	bool "Memory Tagging Extension support"
1769	default y
1770	depends on ARM64_AS_HAS_MTE && ARM64_TAGGED_ADDR_ABI
1771	depends on AS_HAS_ARMV8_5
1772	depends on AS_HAS_LSE_ATOMICS
1773	# Required for tag checking in the uaccess routines
1774	depends on ARM64_PAN
1775	select ARCH_USES_HIGH_VMA_FLAGS
1776	help
1777	  Memory Tagging (part of the ARMv8.5 Extensions) provides
1778	  architectural support for run-time, always-on detection of
1779	  various classes of memory error to aid with software debugging
1780	  to eliminate vulnerabilities arising from memory-unsafe
1781	  languages.
1782
1783	  This option enables the support for the Memory Tagging
1784	  Extension at EL0 (i.e. for userspace).
1785
1786	  Selecting this option allows the feature to be detected at
1787	  runtime. Any secondary CPU not implementing this feature will
1788	  not be allowed a late bring-up.
1789
1790	  Userspace binaries that want to use this feature must
1791	  explicitly opt in. The mechanism for the userspace is
1792	  described in:
1793
1794	  Documentation/arm64/memory-tagging-extension.rst.
1795
1796endmenu
1797
1798menu "ARMv8.7 architectural features"
1799
1800config ARM64_EPAN
1801	bool "Enable support for Enhanced Privileged Access Never (EPAN)"
1802	default y
1803	depends on ARM64_PAN
1804	help
1805	 Enhanced Privileged Access Never (EPAN) allows Privileged
1806	 Access Never to be used with Execute-only mappings.
1807
1808	 The feature is detected at runtime, and will remain disabled
1809	 if the cpu does not implement the feature.
1810endmenu
1811
1812config ARM64_SVE
1813	bool "ARM Scalable Vector Extension support"
1814	default y
1815	help
1816	  The Scalable Vector Extension (SVE) is an extension to the AArch64
1817	  execution state which complements and extends the SIMD functionality
1818	  of the base architecture to support much larger vectors and to enable
1819	  additional vectorisation opportunities.
1820
1821	  To enable use of this extension on CPUs that implement it, say Y.
1822
1823	  On CPUs that support the SVE2 extensions, this option will enable
1824	  those too.
1825
1826	  Note that for architectural reasons, firmware _must_ implement SVE
1827	  support when running on SVE capable hardware.  The required support
1828	  is present in:
1829
1830	    * version 1.5 and later of the ARM Trusted Firmware
1831	    * the AArch64 boot wrapper since commit 5e1261e08abf
1832	      ("bootwrapper: SVE: Enable SVE for EL2 and below").
1833
1834	  For other firmware implementations, consult the firmware documentation
1835	  or vendor.
1836
1837	  If you need the kernel to boot on SVE-capable hardware with broken
1838	  firmware, you may need to say N here until you get your firmware
1839	  fixed.  Otherwise, you may experience firmware panics or lockups when
1840	  booting the kernel.  If unsure and you are not observing these
1841	  symptoms, you should assume that it is safe to say Y.
1842
1843config ARM64_MODULE_PLTS
1844	bool "Use PLTs to allow module memory to spill over into vmalloc area"
1845	depends on MODULES
1846	select HAVE_MOD_ARCH_SPECIFIC
1847	help
1848	  Allocate PLTs when loading modules so that jumps and calls whose
1849	  targets are too far away for their relative offsets to be encoded
1850	  in the instructions themselves can be bounced via veneers in the
1851	  module's PLT. This allows modules to be allocated in the generic
1852	  vmalloc area after the dedicated module memory area has been
1853	  exhausted.
1854
1855	  When running with address space randomization (KASLR), the module
1856	  region itself may be too far away for ordinary relative jumps and
1857	  calls, and so in that case, module PLTs are required and cannot be
1858	  disabled.
1859
1860	  Specific errata workaround(s) might also force module PLTs to be
1861	  enabled (ARM64_ERRATUM_843419).
1862
1863config ARM64_PSEUDO_NMI
1864	bool "Support for NMI-like interrupts"
1865	select ARM_GIC_V3
1866	help
1867	  Adds support for mimicking Non-Maskable Interrupts through the use of
1868	  GIC interrupt priority. This support requires version 3 or later of
1869	  ARM GIC.
1870
1871	  This high priority configuration for interrupts needs to be
1872	  explicitly enabled by setting the kernel parameter
1873	  "irqchip.gicv3_pseudo_nmi" to 1.
1874
1875	  If unsure, say N
1876
1877if ARM64_PSEUDO_NMI
1878config ARM64_DEBUG_PRIORITY_MASKING
1879	bool "Debug interrupt priority masking"
1880	help
1881	  This adds runtime checks to functions enabling/disabling
1882	  interrupts when using priority masking. The additional checks verify
1883	  the validity of ICC_PMR_EL1 when calling concerned functions.
1884
1885	  If unsure, say N
1886endif
1887
1888config RELOCATABLE
1889	bool "Build a relocatable kernel image" if EXPERT
1890	select ARCH_HAS_RELR
1891	default y
1892	help
1893	  This builds the kernel as a Position Independent Executable (PIE),
1894	  which retains all relocation metadata required to relocate the
1895	  kernel binary at runtime to a different virtual address than the
1896	  address it was linked at.
1897	  Since AArch64 uses the RELA relocation format, this requires a
1898	  relocation pass at runtime even if the kernel is loaded at the
1899	  same address it was linked at.
1900
1901config RANDOMIZE_BASE
1902	bool "Randomize the address of the kernel image"
1903	select ARM64_MODULE_PLTS if MODULES
1904	select RELOCATABLE
1905	help
1906	  Randomizes the virtual address at which the kernel image is
1907	  loaded, as a security feature that deters exploit attempts
1908	  relying on knowledge of the location of kernel internals.
1909
1910	  It is the bootloader's job to provide entropy, by passing a
1911	  random u64 value in /chosen/kaslr-seed at kernel entry.
1912
1913	  When booting via the UEFI stub, it will invoke the firmware's
1914	  EFI_RNG_PROTOCOL implementation (if available) to supply entropy
1915	  to the kernel proper. In addition, it will randomise the physical
1916	  location of the kernel Image as well.
1917
1918	  If unsure, say N.
1919
1920config RANDOMIZE_MODULE_REGION_FULL
1921	bool "Randomize the module region over a 2 GB range"
1922	depends on RANDOMIZE_BASE
1923	default y
1924	help
1925	  Randomizes the location of the module region inside a 2 GB window
1926	  covering the core kernel. This way, it is less likely for modules
1927	  to leak information about the location of core kernel data structures
1928	  but it does imply that function calls between modules and the core
1929	  kernel will need to be resolved via veneers in the module PLT.
1930
1931	  When this option is not set, the module region will be randomized over
1932	  a limited range that contains the [_stext, _etext] interval of the
1933	  core kernel, so branch relocations are almost always in range unless
1934	  ARM64_MODULE_PLTS is enabled and the region is exhausted. In this
1935	  particular case of region exhaustion, modules might be able to fall
1936	  back to a larger 2GB area.
1937
1938config CC_HAVE_STACKPROTECTOR_SYSREG
1939	def_bool $(cc-option,-mstack-protector-guard=sysreg -mstack-protector-guard-reg=sp_el0 -mstack-protector-guard-offset=0)
1940
1941config STACKPROTECTOR_PER_TASK
1942	def_bool y
1943	depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_SYSREG
1944
1945endmenu
1946
1947menu "Boot options"
1948
1949config ARM64_ACPI_PARKING_PROTOCOL
1950	bool "Enable support for the ARM64 ACPI parking protocol"
1951	depends on ACPI
1952	help
1953	  Enable support for the ARM64 ACPI parking protocol. If disabled
1954	  the kernel will not allow booting through the ARM64 ACPI parking
1955	  protocol even if the corresponding data is present in the ACPI
1956	  MADT table.
1957
1958config CMDLINE
1959	string "Default kernel command string"
1960	default ""
1961	help
1962	  Provide a set of default command-line options at build time by
1963	  entering them here. As a minimum, you should specify the the
1964	  root device (e.g. root=/dev/nfs).
1965
1966choice
1967	prompt "Kernel command line type" if CMDLINE != ""
1968	default CMDLINE_FROM_BOOTLOADER
1969	help
1970	  Choose how the kernel will handle the provided default kernel
1971	  command line string.
1972
1973config CMDLINE_FROM_BOOTLOADER
1974	bool "Use bootloader kernel arguments if available"
1975	help
1976	  Uses the command-line options passed by the boot loader. If
1977	  the boot loader doesn't provide any, the default kernel command
1978	  string provided in CMDLINE will be used.
1979
1980config CMDLINE_FORCE
1981	bool "Always use the default kernel command string"
1982	help
1983	  Always use the default kernel command string, even if the boot
1984	  loader passes other arguments to the kernel.
1985	  This is useful if you cannot or don't want to change the
1986	  command-line options your boot loader passes to the kernel.
1987
1988endchoice
1989
1990config EFI_STUB
1991	bool
1992
1993config EFI
1994	bool "UEFI runtime support"
1995	depends on OF && !CPU_BIG_ENDIAN
1996	depends on KERNEL_MODE_NEON
1997	select ARCH_SUPPORTS_ACPI
1998	select LIBFDT
1999	select UCS2_STRING
2000	select EFI_PARAMS_FROM_FDT
2001	select EFI_RUNTIME_WRAPPERS
2002	select EFI_STUB
2003	select EFI_GENERIC_STUB
2004	imply IMA_SECURE_AND_OR_TRUSTED_BOOT
2005	default y
2006	help
2007	  This option provides support for runtime services provided
2008	  by UEFI firmware (such as non-volatile variables, realtime
2009          clock, and platform reset). A UEFI stub is also provided to
2010	  allow the kernel to be booted as an EFI application. This
2011	  is only useful on systems that have UEFI firmware.
2012
2013config DMI
2014	bool "Enable support for SMBIOS (DMI) tables"
2015	depends on EFI
2016	default y
2017	help
2018	  This enables SMBIOS/DMI feature for systems.
2019
2020	  This option is only useful on systems that have UEFI firmware.
2021	  However, even with this option, the resultant kernel should
2022	  continue to boot on existing non-UEFI platforms.
2023
2024endmenu
2025
2026config SYSVIPC_COMPAT
2027	def_bool y
2028	depends on COMPAT && SYSVIPC
2029
2030menu "Power management options"
2031
2032source "kernel/power/Kconfig"
2033
2034config ARCH_HIBERNATION_POSSIBLE
2035	def_bool y
2036	depends on CPU_PM
2037
2038config ARCH_HIBERNATION_HEADER
2039	def_bool y
2040	depends on HIBERNATION
2041
2042config ARCH_SUSPEND_POSSIBLE
2043	def_bool y
2044
2045endmenu
2046
2047menu "CPU Power Management"
2048
2049source "drivers/cpuidle/Kconfig"
2050
2051source "drivers/cpufreq/Kconfig"
2052
2053endmenu
2054
2055source "drivers/acpi/Kconfig"
2056
2057source "arch/arm64/kvm/Kconfig"
2058
2059if CRYPTO
2060source "arch/arm64/crypto/Kconfig"
2061endif
2062