xref: /openbmc/linux/arch/arm64/Kconfig (revision 724ba675)
1# SPDX-License-Identifier: GPL-2.0-only
2config ARM64
3	def_bool y
4	select ACPI_APMT if ACPI
5	select ACPI_CCA_REQUIRED if ACPI
6	select ACPI_GENERIC_GSI if ACPI
7	select ACPI_GTDT if ACPI
8	select ACPI_IORT if ACPI
9	select ACPI_REDUCED_HARDWARE_ONLY if ACPI
10	select ACPI_MCFG if (ACPI && PCI)
11	select ACPI_SPCR_TABLE if ACPI
12	select ACPI_PPTT if ACPI
13	select ARCH_HAS_DEBUG_WX
14	select ARCH_BINFMT_ELF_EXTRA_PHDRS
15	select ARCH_BINFMT_ELF_STATE
16	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
17	select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION
18	select ARCH_ENABLE_MEMORY_HOTPLUG
19	select ARCH_ENABLE_MEMORY_HOTREMOVE
20	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
21	select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE
22	select ARCH_HAS_CACHE_LINE_SIZE
23	select ARCH_HAS_CURRENT_STACK_POINTER
24	select ARCH_HAS_DEBUG_VIRTUAL
25	select ARCH_HAS_DEBUG_VM_PGTABLE
26	select ARCH_HAS_DMA_PREP_COHERENT
27	select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
28	select ARCH_HAS_FAST_MULTIPLIER
29	select ARCH_HAS_FORTIFY_SOURCE
30	select ARCH_HAS_GCOV_PROFILE_ALL
31	select ARCH_HAS_GIGANTIC_PAGE
32	select ARCH_HAS_KCOV
33	select ARCH_HAS_KEEPINITRD
34	select ARCH_HAS_MEMBARRIER_SYNC_CORE
35	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
36	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
37	select ARCH_HAS_PTE_DEVMAP
38	select ARCH_HAS_PTE_SPECIAL
39	select ARCH_HAS_SETUP_DMA_OPS
40	select ARCH_HAS_SET_DIRECT_MAP
41	select ARCH_HAS_SET_MEMORY
42	select ARCH_STACKWALK
43	select ARCH_HAS_STRICT_KERNEL_RWX
44	select ARCH_HAS_STRICT_MODULE_RWX
45	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
46	select ARCH_HAS_SYNC_DMA_FOR_CPU
47	select ARCH_HAS_SYSCALL_WRAPPER
48	select ARCH_HAS_TEARDOWN_DMA_OPS if IOMMU_SUPPORT
49	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
50	select ARCH_HAS_ZONE_DMA_SET if EXPERT
51	select ARCH_HAVE_ELF_PROT
52	select ARCH_HAVE_NMI_SAFE_CMPXCHG
53	select ARCH_HAVE_TRACE_MMIO_ACCESS
54	select ARCH_INLINE_READ_LOCK if !PREEMPTION
55	select ARCH_INLINE_READ_LOCK_BH if !PREEMPTION
56	select ARCH_INLINE_READ_LOCK_IRQ if !PREEMPTION
57	select ARCH_INLINE_READ_LOCK_IRQSAVE if !PREEMPTION
58	select ARCH_INLINE_READ_UNLOCK if !PREEMPTION
59	select ARCH_INLINE_READ_UNLOCK_BH if !PREEMPTION
60	select ARCH_INLINE_READ_UNLOCK_IRQ if !PREEMPTION
61	select ARCH_INLINE_READ_UNLOCK_IRQRESTORE if !PREEMPTION
62	select ARCH_INLINE_WRITE_LOCK if !PREEMPTION
63	select ARCH_INLINE_WRITE_LOCK_BH if !PREEMPTION
64	select ARCH_INLINE_WRITE_LOCK_IRQ if !PREEMPTION
65	select ARCH_INLINE_WRITE_LOCK_IRQSAVE if !PREEMPTION
66	select ARCH_INLINE_WRITE_UNLOCK if !PREEMPTION
67	select ARCH_INLINE_WRITE_UNLOCK_BH if !PREEMPTION
68	select ARCH_INLINE_WRITE_UNLOCK_IRQ if !PREEMPTION
69	select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE if !PREEMPTION
70	select ARCH_INLINE_SPIN_TRYLOCK if !PREEMPTION
71	select ARCH_INLINE_SPIN_TRYLOCK_BH if !PREEMPTION
72	select ARCH_INLINE_SPIN_LOCK if !PREEMPTION
73	select ARCH_INLINE_SPIN_LOCK_BH if !PREEMPTION
74	select ARCH_INLINE_SPIN_LOCK_IRQ if !PREEMPTION
75	select ARCH_INLINE_SPIN_LOCK_IRQSAVE if !PREEMPTION
76	select ARCH_INLINE_SPIN_UNLOCK if !PREEMPTION
77	select ARCH_INLINE_SPIN_UNLOCK_BH if !PREEMPTION
78	select ARCH_INLINE_SPIN_UNLOCK_IRQ if !PREEMPTION
79	select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPTION
80	select ARCH_KEEP_MEMBLOCK
81	select ARCH_USE_CMPXCHG_LOCKREF
82	select ARCH_USE_GNU_PROPERTY
83	select ARCH_USE_MEMTEST
84	select ARCH_USE_QUEUED_RWLOCKS
85	select ARCH_USE_QUEUED_SPINLOCKS
86	select ARCH_USE_SYM_ANNOTATIONS
87	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
88	select ARCH_SUPPORTS_HUGETLBFS
89	select ARCH_SUPPORTS_MEMORY_FAILURE
90	select ARCH_SUPPORTS_SHADOW_CALL_STACK if CC_HAVE_SHADOW_CALL_STACK
91	select ARCH_SUPPORTS_LTO_CLANG if CPU_LITTLE_ENDIAN
92	select ARCH_SUPPORTS_LTO_CLANG_THIN
93	select ARCH_SUPPORTS_CFI_CLANG
94	select ARCH_SUPPORTS_ATOMIC_RMW
95	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
96	select ARCH_SUPPORTS_NUMA_BALANCING
97	select ARCH_SUPPORTS_PAGE_TABLE_CHECK
98	select ARCH_SUPPORTS_PER_VMA_LOCK
99	select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT
100	select ARCH_WANT_DEFAULT_BPF_JIT
101	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
102	select ARCH_WANT_FRAME_POINTERS
103	select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
104	select ARCH_WANT_LD_ORPHAN_WARN
105	select ARCH_WANTS_NO_INSTR
106	select ARCH_WANTS_THP_SWAP if ARM64_4K_PAGES
107	select ARCH_HAS_UBSAN_SANITIZE_ALL
108	select ARM_AMBA
109	select ARM_ARCH_TIMER
110	select ARM_GIC
111	select AUDIT_ARCH_COMPAT_GENERIC
112	select ARM_GIC_V2M if PCI
113	select ARM_GIC_V3
114	select ARM_GIC_V3_ITS if PCI
115	select ARM_PSCI_FW
116	select BUILDTIME_TABLE_SORT
117	select CLONE_BACKWARDS
118	select COMMON_CLK
119	select CPU_PM if (SUSPEND || CPU_IDLE)
120	select CRC32
121	select DCACHE_WORD_ACCESS
122	select DYNAMIC_FTRACE if FUNCTION_TRACER
123	select DMA_DIRECT_REMAP
124	select EDAC_SUPPORT
125	select FRAME_POINTER
126	select FUNCTION_ALIGNMENT_4B
127	select FUNCTION_ALIGNMENT_8B if DYNAMIC_FTRACE_WITH_CALL_OPS
128	select GENERIC_ALLOCATOR
129	select GENERIC_ARCH_TOPOLOGY
130	select GENERIC_CLOCKEVENTS_BROADCAST
131	select GENERIC_CPU_AUTOPROBE
132	select GENERIC_CPU_VULNERABILITIES
133	select GENERIC_EARLY_IOREMAP
134	select GENERIC_IDLE_POLL_SETUP
135	select GENERIC_IOREMAP
136	select GENERIC_IRQ_IPI
137	select GENERIC_IRQ_PROBE
138	select GENERIC_IRQ_SHOW
139	select GENERIC_IRQ_SHOW_LEVEL
140	select GENERIC_LIB_DEVMEM_IS_ALLOWED
141	select GENERIC_PCI_IOMAP
142	select GENERIC_PTDUMP
143	select GENERIC_SCHED_CLOCK
144	select GENERIC_SMP_IDLE_THREAD
145	select GENERIC_TIME_VSYSCALL
146	select GENERIC_GETTIMEOFDAY
147	select GENERIC_VDSO_TIME_NS
148	select HARDIRQS_SW_RESEND
149	select HAS_IOPORT
150	select HAVE_MOVE_PMD
151	select HAVE_MOVE_PUD
152	select HAVE_PCI
153	select HAVE_ACPI_APEI if (ACPI && EFI)
154	select HAVE_ALIGNED_STRUCT_PAGE if SLUB
155	select HAVE_ARCH_AUDITSYSCALL
156	select HAVE_ARCH_BITREVERSE
157	select HAVE_ARCH_COMPILER_H
158	select HAVE_ARCH_HUGE_VMALLOC
159	select HAVE_ARCH_HUGE_VMAP
160	select HAVE_ARCH_JUMP_LABEL
161	select HAVE_ARCH_JUMP_LABEL_RELATIVE
162	select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48)
163	select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN
164	select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN
165	select HAVE_ARCH_KASAN_HW_TAGS if (HAVE_ARCH_KASAN && ARM64_MTE)
166	# Some instrumentation may be unsound, hence EXPERT
167	select HAVE_ARCH_KCSAN if EXPERT
168	select HAVE_ARCH_KFENCE
169	select HAVE_ARCH_KGDB
170	select HAVE_ARCH_MMAP_RND_BITS
171	select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
172	select HAVE_ARCH_PREL32_RELOCATIONS
173	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
174	select HAVE_ARCH_SECCOMP_FILTER
175	select HAVE_ARCH_STACKLEAK
176	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
177	select HAVE_ARCH_TRACEHOOK
178	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
179	select HAVE_ARCH_VMAP_STACK
180	select HAVE_ARM_SMCCC
181	select HAVE_ASM_MODVERSIONS
182	select HAVE_EBPF_JIT
183	select HAVE_C_RECORDMCOUNT
184	select HAVE_CMPXCHG_DOUBLE
185	select HAVE_CMPXCHG_LOCAL
186	select HAVE_CONTEXT_TRACKING_USER
187	select HAVE_DEBUG_KMEMLEAK
188	select HAVE_DMA_CONTIGUOUS
189	select HAVE_DYNAMIC_FTRACE
190	select HAVE_DYNAMIC_FTRACE_WITH_ARGS \
191		if $(cc-option,-fpatchable-function-entry=2)
192	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS \
193		if DYNAMIC_FTRACE_WITH_ARGS && DYNAMIC_FTRACE_WITH_CALL_OPS
194	select HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS \
195		if (DYNAMIC_FTRACE_WITH_ARGS && !CFI_CLANG && \
196		    !CC_OPTIMIZE_FOR_SIZE)
197	select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY \
198		if DYNAMIC_FTRACE_WITH_ARGS
199	select HAVE_EFFICIENT_UNALIGNED_ACCESS
200	select HAVE_FAST_GUP
201	select HAVE_FTRACE_MCOUNT_RECORD
202	select HAVE_FUNCTION_TRACER
203	select HAVE_FUNCTION_ERROR_INJECTION
204	select HAVE_FUNCTION_GRAPH_TRACER
205	select HAVE_GCC_PLUGINS
206	select HAVE_HW_BREAKPOINT if PERF_EVENTS
207	select HAVE_IOREMAP_PROT
208	select HAVE_IRQ_TIME_ACCOUNTING
209	select HAVE_KVM
210	select HAVE_NMI
211	select HAVE_PERF_EVENTS
212	select HAVE_PERF_REGS
213	select HAVE_PERF_USER_STACK_DUMP
214	select HAVE_PREEMPT_DYNAMIC_KEY
215	select HAVE_REGS_AND_STACK_ACCESS_API
216	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
217	select HAVE_FUNCTION_ARG_ACCESS_API
218	select MMU_GATHER_RCU_TABLE_FREE
219	select HAVE_RSEQ
220	select HAVE_STACKPROTECTOR
221	select HAVE_SYSCALL_TRACEPOINTS
222	select HAVE_KPROBES
223	select HAVE_KRETPROBES
224	select HAVE_GENERIC_VDSO
225	select IRQ_DOMAIN
226	select IRQ_FORCED_THREADING
227	select KASAN_VMALLOC if KASAN
228	select MODULES_USE_ELF_RELA
229	select NEED_DMA_MAP_STATE
230	select NEED_SG_DMA_LENGTH
231	select OF
232	select OF_EARLY_FLATTREE
233	select PCI_DOMAINS_GENERIC if PCI
234	select PCI_ECAM if (ACPI && PCI)
235	select PCI_SYSCALL if PCI
236	select POWER_RESET
237	select POWER_SUPPLY
238	select SPARSE_IRQ
239	select SWIOTLB
240	select SYSCTL_EXCEPTION_TRACE
241	select THREAD_INFO_IN_TASK
242	select HAVE_ARCH_USERFAULTFD_MINOR if USERFAULTFD
243	select TRACE_IRQFLAGS_SUPPORT
244	select TRACE_IRQFLAGS_NMI_SUPPORT
245	select HAVE_SOFTIRQ_ON_OWN_STACK
246	help
247	  ARM 64-bit (AArch64) Linux support.
248
249config CLANG_SUPPORTS_DYNAMIC_FTRACE_WITH_ARGS
250	def_bool CC_IS_CLANG
251	# https://github.com/ClangBuiltLinux/linux/issues/1507
252	depends on AS_IS_GNU || (AS_IS_LLVM && (LD_IS_LLD || LD_VERSION >= 23600))
253	select HAVE_DYNAMIC_FTRACE_WITH_ARGS
254
255config GCC_SUPPORTS_DYNAMIC_FTRACE_WITH_ARGS
256	def_bool CC_IS_GCC
257	depends on $(cc-option,-fpatchable-function-entry=2)
258	select HAVE_DYNAMIC_FTRACE_WITH_ARGS
259
260config 64BIT
261	def_bool y
262
263config MMU
264	def_bool y
265
266config ARM64_PAGE_SHIFT
267	int
268	default 16 if ARM64_64K_PAGES
269	default 14 if ARM64_16K_PAGES
270	default 12
271
272config ARM64_CONT_PTE_SHIFT
273	int
274	default 5 if ARM64_64K_PAGES
275	default 7 if ARM64_16K_PAGES
276	default 4
277
278config ARM64_CONT_PMD_SHIFT
279	int
280	default 5 if ARM64_64K_PAGES
281	default 5 if ARM64_16K_PAGES
282	default 4
283
284config ARCH_MMAP_RND_BITS_MIN
285	default 14 if ARM64_64K_PAGES
286	default 16 if ARM64_16K_PAGES
287	default 18
288
289# max bits determined by the following formula:
290#  VA_BITS - PAGE_SHIFT - 3
291config ARCH_MMAP_RND_BITS_MAX
292	default 19 if ARM64_VA_BITS=36
293	default 24 if ARM64_VA_BITS=39
294	default 27 if ARM64_VA_BITS=42
295	default 30 if ARM64_VA_BITS=47
296	default 29 if ARM64_VA_BITS=48 && ARM64_64K_PAGES
297	default 31 if ARM64_VA_BITS=48 && ARM64_16K_PAGES
298	default 33 if ARM64_VA_BITS=48
299	default 14 if ARM64_64K_PAGES
300	default 16 if ARM64_16K_PAGES
301	default 18
302
303config ARCH_MMAP_RND_COMPAT_BITS_MIN
304	default 7 if ARM64_64K_PAGES
305	default 9 if ARM64_16K_PAGES
306	default 11
307
308config ARCH_MMAP_RND_COMPAT_BITS_MAX
309	default 16
310
311config NO_IOPORT_MAP
312	def_bool y if !PCI
313
314config STACKTRACE_SUPPORT
315	def_bool y
316
317config ILLEGAL_POINTER_VALUE
318	hex
319	default 0xdead000000000000
320
321config LOCKDEP_SUPPORT
322	def_bool y
323
324config GENERIC_BUG
325	def_bool y
326	depends on BUG
327
328config GENERIC_BUG_RELATIVE_POINTERS
329	def_bool y
330	depends on GENERIC_BUG
331
332config GENERIC_HWEIGHT
333	def_bool y
334
335config GENERIC_CSUM
336	def_bool y
337
338config GENERIC_CALIBRATE_DELAY
339	def_bool y
340
341config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
342	def_bool y
343
344config SMP
345	def_bool y
346
347config KERNEL_MODE_NEON
348	def_bool y
349
350config FIX_EARLYCON_MEM
351	def_bool y
352
353config PGTABLE_LEVELS
354	int
355	default 2 if ARM64_16K_PAGES && ARM64_VA_BITS_36
356	default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42
357	default 3 if ARM64_64K_PAGES && (ARM64_VA_BITS_48 || ARM64_VA_BITS_52)
358	default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39
359	default 3 if ARM64_16K_PAGES && ARM64_VA_BITS_47
360	default 4 if !ARM64_64K_PAGES && ARM64_VA_BITS_48
361
362config ARCH_SUPPORTS_UPROBES
363	def_bool y
364
365config ARCH_PROC_KCORE_TEXT
366	def_bool y
367
368config BROKEN_GAS_INST
369	def_bool !$(as-instr,1:\n.inst 0\n.rept . - 1b\n\nnop\n.endr\n)
370
371config BUILTIN_RETURN_ADDRESS_STRIPS_PAC
372	bool
373	# Clang's __builtin_return_adddress() strips the PAC since 12.0.0
374	# https://reviews.llvm.org/D75044
375	default y if CC_IS_CLANG && (CLANG_VERSION >= 120000)
376	# GCC's __builtin_return_address() strips the PAC since 11.1.0,
377	# and this was backported to 10.2.0, 9.4.0, 8.5.0, but not earlier
378	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94891
379	default y if CC_IS_GCC && (GCC_VERSION >= 110100)
380	default y if CC_IS_GCC && (GCC_VERSION >= 100200) && (GCC_VERSION < 110000)
381	default y if CC_IS_GCC && (GCC_VERSION >=  90400) && (GCC_VERSION < 100000)
382	default y if CC_IS_GCC && (GCC_VERSION >=  80500) && (GCC_VERSION <  90000)
383	default n
384
385config KASAN_SHADOW_OFFSET
386	hex
387	depends on KASAN_GENERIC || KASAN_SW_TAGS
388	default 0xdfff800000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && !KASAN_SW_TAGS
389	default 0xdfffc00000000000 if ARM64_VA_BITS_47 && !KASAN_SW_TAGS
390	default 0xdffffe0000000000 if ARM64_VA_BITS_42 && !KASAN_SW_TAGS
391	default 0xdfffffc000000000 if ARM64_VA_BITS_39 && !KASAN_SW_TAGS
392	default 0xdffffff800000000 if ARM64_VA_BITS_36 && !KASAN_SW_TAGS
393	default 0xefff800000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && KASAN_SW_TAGS
394	default 0xefffc00000000000 if ARM64_VA_BITS_47 && KASAN_SW_TAGS
395	default 0xeffffe0000000000 if ARM64_VA_BITS_42 && KASAN_SW_TAGS
396	default 0xefffffc000000000 if ARM64_VA_BITS_39 && KASAN_SW_TAGS
397	default 0xeffffff800000000 if ARM64_VA_BITS_36 && KASAN_SW_TAGS
398	default 0xffffffffffffffff
399
400config UNWIND_TABLES
401	bool
402
403source "arch/arm64/Kconfig.platforms"
404
405menu "Kernel Features"
406
407menu "ARM errata workarounds via the alternatives framework"
408
409config ARM64_WORKAROUND_CLEAN_CACHE
410	bool
411
412config ARM64_ERRATUM_826319
413	bool "Cortex-A53: 826319: System might deadlock if a write cannot complete until read data is accepted"
414	default y
415	select ARM64_WORKAROUND_CLEAN_CACHE
416	help
417	  This option adds an alternative code sequence to work around ARM
418	  erratum 826319 on Cortex-A53 parts up to r0p2 with an AMBA 4 ACE or
419	  AXI master interface and an L2 cache.
420
421	  If a Cortex-A53 uses an AMBA AXI4 ACE interface to other processors
422	  and is unable to accept a certain write via this interface, it will
423	  not progress on read data presented on the read data channel and the
424	  system can deadlock.
425
426	  The workaround promotes data cache clean instructions to
427	  data cache clean-and-invalidate.
428	  Please note that this does not necessarily enable the workaround,
429	  as it depends on the alternative framework, which will only patch
430	  the kernel if an affected CPU is detected.
431
432	  If unsure, say Y.
433
434config ARM64_ERRATUM_827319
435	bool "Cortex-A53: 827319: Data cache clean instructions might cause overlapping transactions to the interconnect"
436	default y
437	select ARM64_WORKAROUND_CLEAN_CACHE
438	help
439	  This option adds an alternative code sequence to work around ARM
440	  erratum 827319 on Cortex-A53 parts up to r0p2 with an AMBA 5 CHI
441	  master interface and an L2 cache.
442
443	  Under certain conditions this erratum can cause a clean line eviction
444	  to occur at the same time as another transaction to the same address
445	  on the AMBA 5 CHI interface, which can cause data corruption if the
446	  interconnect reorders the two transactions.
447
448	  The workaround promotes data cache clean instructions to
449	  data cache clean-and-invalidate.
450	  Please note that this does not necessarily enable the workaround,
451	  as it depends on the alternative framework, which will only patch
452	  the kernel if an affected CPU is detected.
453
454	  If unsure, say Y.
455
456config ARM64_ERRATUM_824069
457	bool "Cortex-A53: 824069: Cache line might not be marked as clean after a CleanShared snoop"
458	default y
459	select ARM64_WORKAROUND_CLEAN_CACHE
460	help
461	  This option adds an alternative code sequence to work around ARM
462	  erratum 824069 on Cortex-A53 parts up to r0p2 when it is connected
463	  to a coherent interconnect.
464
465	  If a Cortex-A53 processor is executing a store or prefetch for
466	  write instruction at the same time as a processor in another
467	  cluster is executing a cache maintenance operation to the same
468	  address, then this erratum might cause a clean cache line to be
469	  incorrectly marked as dirty.
470
471	  The workaround promotes data cache clean instructions to
472	  data cache clean-and-invalidate.
473	  Please note that this option does not necessarily enable the
474	  workaround, as it depends on the alternative framework, which will
475	  only patch the kernel if an affected CPU is detected.
476
477	  If unsure, say Y.
478
479config ARM64_ERRATUM_819472
480	bool "Cortex-A53: 819472: Store exclusive instructions might cause data corruption"
481	default y
482	select ARM64_WORKAROUND_CLEAN_CACHE
483	help
484	  This option adds an alternative code sequence to work around ARM
485	  erratum 819472 on Cortex-A53 parts up to r0p1 with an L2 cache
486	  present when it is connected to a coherent interconnect.
487
488	  If the processor is executing a load and store exclusive sequence at
489	  the same time as a processor in another cluster is executing a cache
490	  maintenance operation to the same address, then this erratum might
491	  cause data corruption.
492
493	  The workaround promotes data cache clean instructions to
494	  data cache clean-and-invalidate.
495	  Please note that this does not necessarily enable the workaround,
496	  as it depends on the alternative framework, which will only patch
497	  the kernel if an affected CPU is detected.
498
499	  If unsure, say Y.
500
501config ARM64_ERRATUM_832075
502	bool "Cortex-A57: 832075: possible deadlock on mixing exclusive memory accesses with device loads"
503	default y
504	help
505	  This option adds an alternative code sequence to work around ARM
506	  erratum 832075 on Cortex-A57 parts up to r1p2.
507
508	  Affected Cortex-A57 parts might deadlock when exclusive load/store
509	  instructions to Write-Back memory are mixed with Device loads.
510
511	  The workaround is to promote device loads to use Load-Acquire
512	  semantics.
513	  Please note that this does not necessarily enable the workaround,
514	  as it depends on the alternative framework, which will only patch
515	  the kernel if an affected CPU is detected.
516
517	  If unsure, say Y.
518
519config ARM64_ERRATUM_834220
520	bool "Cortex-A57: 834220: Stage 2 translation fault might be incorrectly reported in presence of a Stage 1 fault"
521	depends on KVM
522	default y
523	help
524	  This option adds an alternative code sequence to work around ARM
525	  erratum 834220 on Cortex-A57 parts up to r1p2.
526
527	  Affected Cortex-A57 parts might report a Stage 2 translation
528	  fault as the result of a Stage 1 fault for load crossing a
529	  page boundary when there is a permission or device memory
530	  alignment fault at Stage 1 and a translation fault at Stage 2.
531
532	  The workaround is to verify that the Stage 1 translation
533	  doesn't generate a fault before handling the Stage 2 fault.
534	  Please note that this does not necessarily enable the workaround,
535	  as it depends on the alternative framework, which will only patch
536	  the kernel if an affected CPU is detected.
537
538	  If unsure, say Y.
539
540config ARM64_ERRATUM_1742098
541	bool "Cortex-A57/A72: 1742098: ELR recorded incorrectly on interrupt taken between cryptographic instructions in a sequence"
542	depends on COMPAT
543	default y
544	help
545	  This option removes the AES hwcap for aarch32 user-space to
546	  workaround erratum 1742098 on Cortex-A57 and Cortex-A72.
547
548	  Affected parts may corrupt the AES state if an interrupt is
549	  taken between a pair of AES instructions. These instructions
550	  are only present if the cryptography extensions are present.
551	  All software should have a fallback implementation for CPUs
552	  that don't implement the cryptography extensions.
553
554	  If unsure, say Y.
555
556config ARM64_ERRATUM_845719
557	bool "Cortex-A53: 845719: a load might read incorrect data"
558	depends on COMPAT
559	default y
560	help
561	  This option adds an alternative code sequence to work around ARM
562	  erratum 845719 on Cortex-A53 parts up to r0p4.
563
564	  When running a compat (AArch32) userspace on an affected Cortex-A53
565	  part, a load at EL0 from a virtual address that matches the bottom 32
566	  bits of the virtual address used by a recent load at (AArch64) EL1
567	  might return incorrect data.
568
569	  The workaround is to write the contextidr_el1 register on exception
570	  return to a 32-bit task.
571	  Please note that this does not necessarily enable the workaround,
572	  as it depends on the alternative framework, which will only patch
573	  the kernel if an affected CPU is detected.
574
575	  If unsure, say Y.
576
577config ARM64_ERRATUM_843419
578	bool "Cortex-A53: 843419: A load or store might access an incorrect address"
579	default y
580	select ARM64_MODULE_PLTS if MODULES
581	help
582	  This option links the kernel with '--fix-cortex-a53-843419' and
583	  enables PLT support to replace certain ADRP instructions, which can
584	  cause subsequent memory accesses to use an incorrect address on
585	  Cortex-A53 parts up to r0p4.
586
587	  If unsure, say Y.
588
589config ARM64_LD_HAS_FIX_ERRATUM_843419
590	def_bool $(ld-option,--fix-cortex-a53-843419)
591
592config ARM64_ERRATUM_1024718
593	bool "Cortex-A55: 1024718: Update of DBM/AP bits without break before make might result in incorrect update"
594	default y
595	help
596	  This option adds a workaround for ARM Cortex-A55 Erratum 1024718.
597
598	  Affected Cortex-A55 cores (all revisions) could cause incorrect
599	  update of the hardware dirty bit when the DBM/AP bits are updated
600	  without a break-before-make. The workaround is to disable the usage
601	  of hardware DBM locally on the affected cores. CPUs not affected by
602	  this erratum will continue to use the feature.
603
604	  If unsure, say Y.
605
606config ARM64_ERRATUM_1418040
607	bool "Cortex-A76/Neoverse-N1: MRC read following MRRC read of specific Generic Timer in AArch32 might give incorrect result"
608	default y
609	depends on COMPAT
610	help
611	  This option adds a workaround for ARM Cortex-A76/Neoverse-N1
612	  errata 1188873 and 1418040.
613
614	  Affected Cortex-A76/Neoverse-N1 cores (r0p0 to r3p1) could
615	  cause register corruption when accessing the timer registers
616	  from AArch32 userspace.
617
618	  If unsure, say Y.
619
620config ARM64_WORKAROUND_SPECULATIVE_AT
621	bool
622
623config ARM64_ERRATUM_1165522
624	bool "Cortex-A76: 1165522: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
625	default y
626	select ARM64_WORKAROUND_SPECULATIVE_AT
627	help
628	  This option adds a workaround for ARM Cortex-A76 erratum 1165522.
629
630	  Affected Cortex-A76 cores (r0p0, r1p0, r2p0) could end-up with
631	  corrupted TLBs by speculating an AT instruction during a guest
632	  context switch.
633
634	  If unsure, say Y.
635
636config ARM64_ERRATUM_1319367
637	bool "Cortex-A57/A72: 1319537: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
638	default y
639	select ARM64_WORKAROUND_SPECULATIVE_AT
640	help
641	  This option adds work arounds for ARM Cortex-A57 erratum 1319537
642	  and A72 erratum 1319367
643
644	  Cortex-A57 and A72 cores could end-up with corrupted TLBs by
645	  speculating an AT instruction during a guest context switch.
646
647	  If unsure, say Y.
648
649config ARM64_ERRATUM_1530923
650	bool "Cortex-A55: 1530923: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
651	default y
652	select ARM64_WORKAROUND_SPECULATIVE_AT
653	help
654	  This option adds a workaround for ARM Cortex-A55 erratum 1530923.
655
656	  Affected Cortex-A55 cores (r0p0, r0p1, r1p0, r2p0) could end-up with
657	  corrupted TLBs by speculating an AT instruction during a guest
658	  context switch.
659
660	  If unsure, say Y.
661
662config ARM64_WORKAROUND_REPEAT_TLBI
663	bool
664
665config ARM64_ERRATUM_2441007
666	bool "Cortex-A55: Completion of affected memory accesses might not be guaranteed by completion of a TLBI"
667	default y
668	select ARM64_WORKAROUND_REPEAT_TLBI
669	help
670	  This option adds a workaround for ARM Cortex-A55 erratum #2441007.
671
672	  Under very rare circumstances, affected Cortex-A55 CPUs
673	  may not handle a race between a break-before-make sequence on one
674	  CPU, and another CPU accessing the same page. This could allow a
675	  store to a page that has been unmapped.
676
677	  Work around this by adding the affected CPUs to the list that needs
678	  TLB sequences to be done twice.
679
680	  If unsure, say Y.
681
682config ARM64_ERRATUM_1286807
683	bool "Cortex-A76: Modification of the translation table for a virtual address might lead to read-after-read ordering violation"
684	default y
685	select ARM64_WORKAROUND_REPEAT_TLBI
686	help
687	  This option adds a workaround for ARM Cortex-A76 erratum 1286807.
688
689	  On the affected Cortex-A76 cores (r0p0 to r3p0), if a virtual
690	  address for a cacheable mapping of a location is being
691	  accessed by a core while another core is remapping the virtual
692	  address to a new physical page using the recommended
693	  break-before-make sequence, then under very rare circumstances
694	  TLBI+DSB completes before a read using the translation being
695	  invalidated has been observed by other observers. The
696	  workaround repeats the TLBI+DSB operation.
697
698config ARM64_ERRATUM_1463225
699	bool "Cortex-A76: Software Step might prevent interrupt recognition"
700	default y
701	help
702	  This option adds a workaround for Arm Cortex-A76 erratum 1463225.
703
704	  On the affected Cortex-A76 cores (r0p0 to r3p1), software stepping
705	  of a system call instruction (SVC) can prevent recognition of
706	  subsequent interrupts when software stepping is disabled in the
707	  exception handler of the system call and either kernel debugging
708	  is enabled or VHE is in use.
709
710	  Work around the erratum by triggering a dummy step exception
711	  when handling a system call from a task that is being stepped
712	  in a VHE configuration of the kernel.
713
714	  If unsure, say Y.
715
716config ARM64_ERRATUM_1542419
717	bool "Neoverse-N1: workaround mis-ordering of instruction fetches"
718	default y
719	help
720	  This option adds a workaround for ARM Neoverse-N1 erratum
721	  1542419.
722
723	  Affected Neoverse-N1 cores could execute a stale instruction when
724	  modified by another CPU. The workaround depends on a firmware
725	  counterpart.
726
727	  Workaround the issue by hiding the DIC feature from EL0. This
728	  forces user-space to perform cache maintenance.
729
730	  If unsure, say Y.
731
732config ARM64_ERRATUM_1508412
733	bool "Cortex-A77: 1508412: workaround deadlock on sequence of NC/Device load and store exclusive or PAR read"
734	default y
735	help
736	  This option adds a workaround for Arm Cortex-A77 erratum 1508412.
737
738	  Affected Cortex-A77 cores (r0p0, r1p0) could deadlock on a sequence
739	  of a store-exclusive or read of PAR_EL1 and a load with device or
740	  non-cacheable memory attributes. The workaround depends on a firmware
741	  counterpart.
742
743	  KVM guests must also have the workaround implemented or they can
744	  deadlock the system.
745
746	  Work around the issue by inserting DMB SY barriers around PAR_EL1
747	  register reads and warning KVM users. The DMB barrier is sufficient
748	  to prevent a speculative PAR_EL1 read.
749
750	  If unsure, say Y.
751
752config ARM64_WORKAROUND_TRBE_OVERWRITE_FILL_MODE
753	bool
754
755config ARM64_ERRATUM_2051678
756	bool "Cortex-A510: 2051678: disable Hardware Update of the page table dirty bit"
757	default y
758	help
759	  This options adds the workaround for ARM Cortex-A510 erratum ARM64_ERRATUM_2051678.
760	  Affected Cortex-A510 might not respect the ordering rules for
761	  hardware update of the page table's dirty bit. The workaround
762	  is to not enable the feature on affected CPUs.
763
764	  If unsure, say Y.
765
766config ARM64_ERRATUM_2077057
767	bool "Cortex-A510: 2077057: workaround software-step corrupting SPSR_EL2"
768	default y
769	help
770	  This option adds the workaround for ARM Cortex-A510 erratum 2077057.
771	  Affected Cortex-A510 may corrupt SPSR_EL2 when the a step exception is
772	  expected, but a Pointer Authentication trap is taken instead. The
773	  erratum causes SPSR_EL1 to be copied to SPSR_EL2, which could allow
774	  EL1 to cause a return to EL2 with a guest controlled ELR_EL2.
775
776	  This can only happen when EL2 is stepping EL1.
777
778	  When these conditions occur, the SPSR_EL2 value is unchanged from the
779	  previous guest entry, and can be restored from the in-memory copy.
780
781	  If unsure, say Y.
782
783config ARM64_ERRATUM_2658417
784	bool "Cortex-A510: 2658417: remove BF16 support due to incorrect result"
785	default y
786	help
787	  This option adds the workaround for ARM Cortex-A510 erratum 2658417.
788	  Affected Cortex-A510 (r0p0 to r1p1) may produce the wrong result for
789	  BFMMLA or VMMLA instructions in rare circumstances when a pair of
790	  A510 CPUs are using shared neon hardware. As the sharing is not
791	  discoverable by the kernel, hide the BF16 HWCAP to indicate that
792	  user-space should not be using these instructions.
793
794	  If unsure, say Y.
795
796config ARM64_ERRATUM_2119858
797	bool "Cortex-A710/X2: 2119858: workaround TRBE overwriting trace data in FILL mode"
798	default y
799	depends on CORESIGHT_TRBE
800	select ARM64_WORKAROUND_TRBE_OVERWRITE_FILL_MODE
801	help
802	  This option adds the workaround for ARM Cortex-A710/X2 erratum 2119858.
803
804	  Affected Cortex-A710/X2 cores could overwrite up to 3 cache lines of trace
805	  data at the base of the buffer (pointed to by TRBASER_EL1) in FILL mode in
806	  the event of a WRAP event.
807
808	  Work around the issue by always making sure we move the TRBPTR_EL1 by
809	  256 bytes before enabling the buffer and filling the first 256 bytes of
810	  the buffer with ETM ignore packets upon disabling.
811
812	  If unsure, say Y.
813
814config ARM64_ERRATUM_2139208
815	bool "Neoverse-N2: 2139208: workaround TRBE overwriting trace data in FILL mode"
816	default y
817	depends on CORESIGHT_TRBE
818	select ARM64_WORKAROUND_TRBE_OVERWRITE_FILL_MODE
819	help
820	  This option adds the workaround for ARM Neoverse-N2 erratum 2139208.
821
822	  Affected Neoverse-N2 cores could overwrite up to 3 cache lines of trace
823	  data at the base of the buffer (pointed to by TRBASER_EL1) in FILL mode in
824	  the event of a WRAP event.
825
826	  Work around the issue by always making sure we move the TRBPTR_EL1 by
827	  256 bytes before enabling the buffer and filling the first 256 bytes of
828	  the buffer with ETM ignore packets upon disabling.
829
830	  If unsure, say Y.
831
832config ARM64_WORKAROUND_TSB_FLUSH_FAILURE
833	bool
834
835config ARM64_ERRATUM_2054223
836	bool "Cortex-A710: 2054223: workaround TSB instruction failing to flush trace"
837	default y
838	select ARM64_WORKAROUND_TSB_FLUSH_FAILURE
839	help
840	  Enable workaround for ARM Cortex-A710 erratum 2054223
841
842	  Affected cores may fail to flush the trace data on a TSB instruction, when
843	  the PE is in trace prohibited state. This will cause losing a few bytes
844	  of the trace cached.
845
846	  Workaround is to issue two TSB consecutively on affected cores.
847
848	  If unsure, say Y.
849
850config ARM64_ERRATUM_2067961
851	bool "Neoverse-N2: 2067961: workaround TSB instruction failing to flush trace"
852	default y
853	select ARM64_WORKAROUND_TSB_FLUSH_FAILURE
854	help
855	  Enable workaround for ARM Neoverse-N2 erratum 2067961
856
857	  Affected cores may fail to flush the trace data on a TSB instruction, when
858	  the PE is in trace prohibited state. This will cause losing a few bytes
859	  of the trace cached.
860
861	  Workaround is to issue two TSB consecutively on affected cores.
862
863	  If unsure, say Y.
864
865config ARM64_WORKAROUND_TRBE_WRITE_OUT_OF_RANGE
866	bool
867
868config ARM64_ERRATUM_2253138
869	bool "Neoverse-N2: 2253138: workaround TRBE writing to address out-of-range"
870	depends on CORESIGHT_TRBE
871	default y
872	select ARM64_WORKAROUND_TRBE_WRITE_OUT_OF_RANGE
873	help
874	  This option adds the workaround for ARM Neoverse-N2 erratum 2253138.
875
876	  Affected Neoverse-N2 cores might write to an out-of-range address, not reserved
877	  for TRBE. Under some conditions, the TRBE might generate a write to the next
878	  virtually addressed page following the last page of the TRBE address space
879	  (i.e., the TRBLIMITR_EL1.LIMIT), instead of wrapping around to the base.
880
881	  Work around this in the driver by always making sure that there is a
882	  page beyond the TRBLIMITR_EL1.LIMIT, within the space allowed for the TRBE.
883
884	  If unsure, say Y.
885
886config ARM64_ERRATUM_2224489
887	bool "Cortex-A710/X2: 2224489: workaround TRBE writing to address out-of-range"
888	depends on CORESIGHT_TRBE
889	default y
890	select ARM64_WORKAROUND_TRBE_WRITE_OUT_OF_RANGE
891	help
892	  This option adds the workaround for ARM Cortex-A710/X2 erratum 2224489.
893
894	  Affected Cortex-A710/X2 cores might write to an out-of-range address, not reserved
895	  for TRBE. Under some conditions, the TRBE might generate a write to the next
896	  virtually addressed page following the last page of the TRBE address space
897	  (i.e., the TRBLIMITR_EL1.LIMIT), instead of wrapping around to the base.
898
899	  Work around this in the driver by always making sure that there is a
900	  page beyond the TRBLIMITR_EL1.LIMIT, within the space allowed for the TRBE.
901
902	  If unsure, say Y.
903
904config ARM64_ERRATUM_2441009
905	bool "Cortex-A510: Completion of affected memory accesses might not be guaranteed by completion of a TLBI"
906	default y
907	select ARM64_WORKAROUND_REPEAT_TLBI
908	help
909	  This option adds a workaround for ARM Cortex-A510 erratum #2441009.
910
911	  Under very rare circumstances, affected Cortex-A510 CPUs
912	  may not handle a race between a break-before-make sequence on one
913	  CPU, and another CPU accessing the same page. This could allow a
914	  store to a page that has been unmapped.
915
916	  Work around this by adding the affected CPUs to the list that needs
917	  TLB sequences to be done twice.
918
919	  If unsure, say Y.
920
921config ARM64_ERRATUM_2064142
922	bool "Cortex-A510: 2064142: workaround TRBE register writes while disabled"
923	depends on CORESIGHT_TRBE
924	default y
925	help
926	  This option adds the workaround for ARM Cortex-A510 erratum 2064142.
927
928	  Affected Cortex-A510 core might fail to write into system registers after the
929	  TRBE has been disabled. Under some conditions after the TRBE has been disabled
930	  writes into TRBE registers TRBLIMITR_EL1, TRBPTR_EL1, TRBBASER_EL1, TRBSR_EL1,
931	  and TRBTRG_EL1 will be ignored and will not be effected.
932
933	  Work around this in the driver by executing TSB CSYNC and DSB after collection
934	  is stopped and before performing a system register write to one of the affected
935	  registers.
936
937	  If unsure, say Y.
938
939config ARM64_ERRATUM_2038923
940	bool "Cortex-A510: 2038923: workaround TRBE corruption with enable"
941	depends on CORESIGHT_TRBE
942	default y
943	help
944	  This option adds the workaround for ARM Cortex-A510 erratum 2038923.
945
946	  Affected Cortex-A510 core might cause an inconsistent view on whether trace is
947	  prohibited within the CPU. As a result, the trace buffer or trace buffer state
948	  might be corrupted. This happens after TRBE buffer has been enabled by setting
949	  TRBLIMITR_EL1.E, followed by just a single context synchronization event before
950	  execution changes from a context, in which trace is prohibited to one where it
951	  isn't, or vice versa. In these mentioned conditions, the view of whether trace
952	  is prohibited is inconsistent between parts of the CPU, and the trace buffer or
953	  the trace buffer state might be corrupted.
954
955	  Work around this in the driver by preventing an inconsistent view of whether the
956	  trace is prohibited or not based on TRBLIMITR_EL1.E by immediately following a
957	  change to TRBLIMITR_EL1.E with at least one ISB instruction before an ERET, or
958	  two ISB instructions if no ERET is to take place.
959
960	  If unsure, say Y.
961
962config ARM64_ERRATUM_1902691
963	bool "Cortex-A510: 1902691: workaround TRBE trace corruption"
964	depends on CORESIGHT_TRBE
965	default y
966	help
967	  This option adds the workaround for ARM Cortex-A510 erratum 1902691.
968
969	  Affected Cortex-A510 core might cause trace data corruption, when being written
970	  into the memory. Effectively TRBE is broken and hence cannot be used to capture
971	  trace data.
972
973	  Work around this problem in the driver by just preventing TRBE initialization on
974	  affected cpus. The firmware must have disabled the access to TRBE for the kernel
975	  on such implementations. This will cover the kernel for any firmware that doesn't
976	  do this already.
977
978	  If unsure, say Y.
979
980config ARM64_ERRATUM_2457168
981	bool "Cortex-A510: 2457168: workaround for AMEVCNTR01 incrementing incorrectly"
982	depends on ARM64_AMU_EXTN
983	default y
984	help
985	  This option adds the workaround for ARM Cortex-A510 erratum 2457168.
986
987	  The AMU counter AMEVCNTR01 (constant counter) should increment at the same rate
988	  as the system counter. On affected Cortex-A510 cores AMEVCNTR01 increments
989	  incorrectly giving a significantly higher output value.
990
991	  Work around this problem by returning 0 when reading the affected counter in
992	  key locations that results in disabling all users of this counter. This effect
993	  is the same to firmware disabling affected counters.
994
995	  If unsure, say Y.
996
997config ARM64_ERRATUM_2645198
998	bool "Cortex-A715: 2645198: Workaround possible [ESR|FAR]_ELx corruption"
999	default y
1000	help
1001	  This option adds the workaround for ARM Cortex-A715 erratum 2645198.
1002
1003	  If a Cortex-A715 cpu sees a page mapping permissions change from executable
1004	  to non-executable, it may corrupt the ESR_ELx and FAR_ELx registers on the
1005	  next instruction abort caused by permission fault.
1006
1007	  Only user-space does executable to non-executable permission transition via
1008	  mprotect() system call. Workaround the problem by doing a break-before-make
1009	  TLB invalidation, for all changes to executable user space mappings.
1010
1011	  If unsure, say Y.
1012
1013config CAVIUM_ERRATUM_22375
1014	bool "Cavium erratum 22375, 24313"
1015	default y
1016	help
1017	  Enable workaround for errata 22375 and 24313.
1018
1019	  This implements two gicv3-its errata workarounds for ThunderX. Both
1020	  with a small impact affecting only ITS table allocation.
1021
1022	    erratum 22375: only alloc 8MB table size
1023	    erratum 24313: ignore memory access type
1024
1025	  The fixes are in ITS initialization and basically ignore memory access
1026	  type and table size provided by the TYPER and BASER registers.
1027
1028	  If unsure, say Y.
1029
1030config CAVIUM_ERRATUM_23144
1031	bool "Cavium erratum 23144: ITS SYNC hang on dual socket system"
1032	depends on NUMA
1033	default y
1034	help
1035	  ITS SYNC command hang for cross node io and collections/cpu mapping.
1036
1037	  If unsure, say Y.
1038
1039config CAVIUM_ERRATUM_23154
1040	bool "Cavium errata 23154 and 38545: GICv3 lacks HW synchronisation"
1041	default y
1042	help
1043	  The ThunderX GICv3 implementation requires a modified version for
1044	  reading the IAR status to ensure data synchronization
1045	  (access to icc_iar1_el1 is not sync'ed before and after).
1046
1047	  It also suffers from erratum 38545 (also present on Marvell's
1048	  OcteonTX and OcteonTX2), resulting in deactivated interrupts being
1049	  spuriously presented to the CPU interface.
1050
1051	  If unsure, say Y.
1052
1053config CAVIUM_ERRATUM_27456
1054	bool "Cavium erratum 27456: Broadcast TLBI instructions may cause icache corruption"
1055	default y
1056	help
1057	  On ThunderX T88 pass 1.x through 2.1 parts, broadcast TLBI
1058	  instructions may cause the icache to become corrupted if it
1059	  contains data for a non-current ASID.  The fix is to
1060	  invalidate the icache when changing the mm context.
1061
1062	  If unsure, say Y.
1063
1064config CAVIUM_ERRATUM_30115
1065	bool "Cavium erratum 30115: Guest may disable interrupts in host"
1066	default y
1067	help
1068	  On ThunderX T88 pass 1.x through 2.2, T81 pass 1.0 through
1069	  1.2, and T83 Pass 1.0, KVM guest execution may disable
1070	  interrupts in host. Trapping both GICv3 group-0 and group-1
1071	  accesses sidesteps the issue.
1072
1073	  If unsure, say Y.
1074
1075config CAVIUM_TX2_ERRATUM_219
1076	bool "Cavium ThunderX2 erratum 219: PRFM between TTBR change and ISB fails"
1077	default y
1078	help
1079	  On Cavium ThunderX2, a load, store or prefetch instruction between a
1080	  TTBR update and the corresponding context synchronizing operation can
1081	  cause a spurious Data Abort to be delivered to any hardware thread in
1082	  the CPU core.
1083
1084	  Work around the issue by avoiding the problematic code sequence and
1085	  trapping KVM guest TTBRx_EL1 writes to EL2 when SMT is enabled. The
1086	  trap handler performs the corresponding register access, skips the
1087	  instruction and ensures context synchronization by virtue of the
1088	  exception return.
1089
1090	  If unsure, say Y.
1091
1092config FUJITSU_ERRATUM_010001
1093	bool "Fujitsu-A64FX erratum E#010001: Undefined fault may occur wrongly"
1094	default y
1095	help
1096	  This option adds a workaround for Fujitsu-A64FX erratum E#010001.
1097	  On some variants of the Fujitsu-A64FX cores ver(1.0, 1.1), memory
1098	  accesses may cause undefined fault (Data abort, DFSC=0b111111).
1099	  This fault occurs under a specific hardware condition when a
1100	  load/store instruction performs an address translation using:
1101	  case-1  TTBR0_EL1 with TCR_EL1.NFD0 == 1.
1102	  case-2  TTBR0_EL2 with TCR_EL2.NFD0 == 1.
1103	  case-3  TTBR1_EL1 with TCR_EL1.NFD1 == 1.
1104	  case-4  TTBR1_EL2 with TCR_EL2.NFD1 == 1.
1105
1106	  The workaround is to ensure these bits are clear in TCR_ELx.
1107	  The workaround only affects the Fujitsu-A64FX.
1108
1109	  If unsure, say Y.
1110
1111config HISILICON_ERRATUM_161600802
1112	bool "Hip07 161600802: Erroneous redistributor VLPI base"
1113	default y
1114	help
1115	  The HiSilicon Hip07 SoC uses the wrong redistributor base
1116	  when issued ITS commands such as VMOVP and VMAPP, and requires
1117	  a 128kB offset to be applied to the target address in this commands.
1118
1119	  If unsure, say Y.
1120
1121config QCOM_FALKOR_ERRATUM_1003
1122	bool "Falkor E1003: Incorrect translation due to ASID change"
1123	default y
1124	help
1125	  On Falkor v1, an incorrect ASID may be cached in the TLB when ASID
1126	  and BADDR are changed together in TTBRx_EL1. Since we keep the ASID
1127	  in TTBR1_EL1, this situation only occurs in the entry trampoline and
1128	  then only for entries in the walk cache, since the leaf translation
1129	  is unchanged. Work around the erratum by invalidating the walk cache
1130	  entries for the trampoline before entering the kernel proper.
1131
1132config QCOM_FALKOR_ERRATUM_1009
1133	bool "Falkor E1009: Prematurely complete a DSB after a TLBI"
1134	default y
1135	select ARM64_WORKAROUND_REPEAT_TLBI
1136	help
1137	  On Falkor v1, the CPU may prematurely complete a DSB following a
1138	  TLBI xxIS invalidate maintenance operation. Repeat the TLBI operation
1139	  one more time to fix the issue.
1140
1141	  If unsure, say Y.
1142
1143config QCOM_QDF2400_ERRATUM_0065
1144	bool "QDF2400 E0065: Incorrect GITS_TYPER.ITT_Entry_size"
1145	default y
1146	help
1147	  On Qualcomm Datacenter Technologies QDF2400 SoC, ITS hardware reports
1148	  ITE size incorrectly. The GITS_TYPER.ITT_Entry_size field should have
1149	  been indicated as 16Bytes (0xf), not 8Bytes (0x7).
1150
1151	  If unsure, say Y.
1152
1153config QCOM_FALKOR_ERRATUM_E1041
1154	bool "Falkor E1041: Speculative instruction fetches might cause errant memory access"
1155	default y
1156	help
1157	  Falkor CPU may speculatively fetch instructions from an improper
1158	  memory location when MMU translation is changed from SCTLR_ELn[M]=1
1159	  to SCTLR_ELn[M]=0. Prefix an ISB instruction to fix the problem.
1160
1161	  If unsure, say Y.
1162
1163config NVIDIA_CARMEL_CNP_ERRATUM
1164	bool "NVIDIA Carmel CNP: CNP on Carmel semantically different than ARM cores"
1165	default y
1166	help
1167	  If CNP is enabled on Carmel cores, non-sharable TLBIs on a core will not
1168	  invalidate shared TLB entries installed by a different core, as it would
1169	  on standard ARM cores.
1170
1171	  If unsure, say Y.
1172
1173config ROCKCHIP_ERRATUM_3588001
1174	bool "Rockchip 3588001: GIC600 can not support shareability attributes"
1175	default y
1176	help
1177	  The Rockchip RK3588 GIC600 SoC integration does not support ACE/ACE-lite.
1178	  This means, that its sharability feature may not be used, even though it
1179	  is supported by the IP itself.
1180
1181	  If unsure, say Y.
1182
1183config SOCIONEXT_SYNQUACER_PREITS
1184	bool "Socionext Synquacer: Workaround for GICv3 pre-ITS"
1185	default y
1186	help
1187	  Socionext Synquacer SoCs implement a separate h/w block to generate
1188	  MSI doorbell writes with non-zero values for the device ID.
1189
1190	  If unsure, say Y.
1191
1192endmenu # "ARM errata workarounds via the alternatives framework"
1193
1194choice
1195	prompt "Page size"
1196	default ARM64_4K_PAGES
1197	help
1198	  Page size (translation granule) configuration.
1199
1200config ARM64_4K_PAGES
1201	bool "4KB"
1202	help
1203	  This feature enables 4KB pages support.
1204
1205config ARM64_16K_PAGES
1206	bool "16KB"
1207	help
1208	  The system will use 16KB pages support. AArch32 emulation
1209	  requires applications compiled with 16K (or a multiple of 16K)
1210	  aligned segments.
1211
1212config ARM64_64K_PAGES
1213	bool "64KB"
1214	help
1215	  This feature enables 64KB pages support (4KB by default)
1216	  allowing only two levels of page tables and faster TLB
1217	  look-up. AArch32 emulation requires applications compiled
1218	  with 64K aligned segments.
1219
1220endchoice
1221
1222choice
1223	prompt "Virtual address space size"
1224	default ARM64_VA_BITS_39 if ARM64_4K_PAGES
1225	default ARM64_VA_BITS_47 if ARM64_16K_PAGES
1226	default ARM64_VA_BITS_42 if ARM64_64K_PAGES
1227	help
1228	  Allows choosing one of multiple possible virtual address
1229	  space sizes. The level of translation table is determined by
1230	  a combination of page size and virtual address space size.
1231
1232config ARM64_VA_BITS_36
1233	bool "36-bit" if EXPERT
1234	depends on ARM64_16K_PAGES
1235
1236config ARM64_VA_BITS_39
1237	bool "39-bit"
1238	depends on ARM64_4K_PAGES
1239
1240config ARM64_VA_BITS_42
1241	bool "42-bit"
1242	depends on ARM64_64K_PAGES
1243
1244config ARM64_VA_BITS_47
1245	bool "47-bit"
1246	depends on ARM64_16K_PAGES
1247
1248config ARM64_VA_BITS_48
1249	bool "48-bit"
1250
1251config ARM64_VA_BITS_52
1252	bool "52-bit"
1253	depends on ARM64_64K_PAGES && (ARM64_PAN || !ARM64_SW_TTBR0_PAN)
1254	help
1255	  Enable 52-bit virtual addressing for userspace when explicitly
1256	  requested via a hint to mmap(). The kernel will also use 52-bit
1257	  virtual addresses for its own mappings (provided HW support for
1258	  this feature is available, otherwise it reverts to 48-bit).
1259
1260	  NOTE: Enabling 52-bit virtual addressing in conjunction with
1261	  ARMv8.3 Pointer Authentication will result in the PAC being
1262	  reduced from 7 bits to 3 bits, which may have a significant
1263	  impact on its susceptibility to brute-force attacks.
1264
1265	  If unsure, select 48-bit virtual addressing instead.
1266
1267endchoice
1268
1269config ARM64_FORCE_52BIT
1270	bool "Force 52-bit virtual addresses for userspace"
1271	depends on ARM64_VA_BITS_52 && EXPERT
1272	help
1273	  For systems with 52-bit userspace VAs enabled, the kernel will attempt
1274	  to maintain compatibility with older software by providing 48-bit VAs
1275	  unless a hint is supplied to mmap.
1276
1277	  This configuration option disables the 48-bit compatibility logic, and
1278	  forces all userspace addresses to be 52-bit on HW that supports it. One
1279	  should only enable this configuration option for stress testing userspace
1280	  memory management code. If unsure say N here.
1281
1282config ARM64_VA_BITS
1283	int
1284	default 36 if ARM64_VA_BITS_36
1285	default 39 if ARM64_VA_BITS_39
1286	default 42 if ARM64_VA_BITS_42
1287	default 47 if ARM64_VA_BITS_47
1288	default 48 if ARM64_VA_BITS_48
1289	default 52 if ARM64_VA_BITS_52
1290
1291choice
1292	prompt "Physical address space size"
1293	default ARM64_PA_BITS_48
1294	help
1295	  Choose the maximum physical address range that the kernel will
1296	  support.
1297
1298config ARM64_PA_BITS_48
1299	bool "48-bit"
1300
1301config ARM64_PA_BITS_52
1302	bool "52-bit (ARMv8.2)"
1303	depends on ARM64_64K_PAGES
1304	depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
1305	help
1306	  Enable support for a 52-bit physical address space, introduced as
1307	  part of the ARMv8.2-LPA extension.
1308
1309	  With this enabled, the kernel will also continue to work on CPUs that
1310	  do not support ARMv8.2-LPA, but with some added memory overhead (and
1311	  minor performance overhead).
1312
1313endchoice
1314
1315config ARM64_PA_BITS
1316	int
1317	default 48 if ARM64_PA_BITS_48
1318	default 52 if ARM64_PA_BITS_52
1319
1320choice
1321	prompt "Endianness"
1322	default CPU_LITTLE_ENDIAN
1323	help
1324	  Select the endianness of data accesses performed by the CPU. Userspace
1325	  applications will need to be compiled and linked for the endianness
1326	  that is selected here.
1327
1328config CPU_BIG_ENDIAN
1329	bool "Build big-endian kernel"
1330	depends on !LD_IS_LLD || LLD_VERSION >= 130000
1331	help
1332	  Say Y if you plan on running a kernel with a big-endian userspace.
1333
1334config CPU_LITTLE_ENDIAN
1335	bool "Build little-endian kernel"
1336	help
1337	  Say Y if you plan on running a kernel with a little-endian userspace.
1338	  This is usually the case for distributions targeting arm64.
1339
1340endchoice
1341
1342config SCHED_MC
1343	bool "Multi-core scheduler support"
1344	help
1345	  Multi-core scheduler support improves the CPU scheduler's decision
1346	  making when dealing with multi-core CPU chips at a cost of slightly
1347	  increased overhead in some places. If unsure say N here.
1348
1349config SCHED_CLUSTER
1350	bool "Cluster scheduler support"
1351	help
1352	  Cluster scheduler support improves the CPU scheduler's decision
1353	  making when dealing with machines that have clusters of CPUs.
1354	  Cluster usually means a couple of CPUs which are placed closely
1355	  by sharing mid-level caches, last-level cache tags or internal
1356	  busses.
1357
1358config SCHED_SMT
1359	bool "SMT scheduler support"
1360	help
1361	  Improves the CPU scheduler's decision making when dealing with
1362	  MultiThreading at a cost of slightly increased overhead in some
1363	  places. If unsure say N here.
1364
1365config NR_CPUS
1366	int "Maximum number of CPUs (2-4096)"
1367	range 2 4096
1368	default "256"
1369
1370config HOTPLUG_CPU
1371	bool "Support for hot-pluggable CPUs"
1372	select GENERIC_IRQ_MIGRATION
1373	help
1374	  Say Y here to experiment with turning CPUs off and on.  CPUs
1375	  can be controlled through /sys/devices/system/cpu.
1376
1377# Common NUMA Features
1378config NUMA
1379	bool "NUMA Memory Allocation and Scheduler Support"
1380	select GENERIC_ARCH_NUMA
1381	select ACPI_NUMA if ACPI
1382	select OF_NUMA
1383	select HAVE_SETUP_PER_CPU_AREA
1384	select NEED_PER_CPU_EMBED_FIRST_CHUNK
1385	select NEED_PER_CPU_PAGE_FIRST_CHUNK
1386	select USE_PERCPU_NUMA_NODE_ID
1387	help
1388	  Enable NUMA (Non-Uniform Memory Access) support.
1389
1390	  The kernel will try to allocate memory used by a CPU on the
1391	  local memory of the CPU and add some more
1392	  NUMA awareness to the kernel.
1393
1394config NODES_SHIFT
1395	int "Maximum NUMA Nodes (as a power of 2)"
1396	range 1 10
1397	default "4"
1398	depends on NUMA
1399	help
1400	  Specify the maximum number of NUMA Nodes available on the target
1401	  system.  Increases memory reserved to accommodate various tables.
1402
1403source "kernel/Kconfig.hz"
1404
1405config ARCH_SPARSEMEM_ENABLE
1406	def_bool y
1407	select SPARSEMEM_VMEMMAP_ENABLE
1408	select SPARSEMEM_VMEMMAP
1409
1410config HW_PERF_EVENTS
1411	def_bool y
1412	depends on ARM_PMU
1413
1414# Supported by clang >= 7.0 or GCC >= 12.0.0
1415config CC_HAVE_SHADOW_CALL_STACK
1416	def_bool $(cc-option, -fsanitize=shadow-call-stack -ffixed-x18)
1417
1418config PARAVIRT
1419	bool "Enable paravirtualization code"
1420	help
1421	  This changes the kernel so it can modify itself when it is run
1422	  under a hypervisor, potentially improving performance significantly
1423	  over full virtualization.
1424
1425config PARAVIRT_TIME_ACCOUNTING
1426	bool "Paravirtual steal time accounting"
1427	select PARAVIRT
1428	help
1429	  Select this option to enable fine granularity task steal time
1430	  accounting. Time spent executing other tasks in parallel with
1431	  the current vCPU is discounted from the vCPU power. To account for
1432	  that, there can be a small performance impact.
1433
1434	  If in doubt, say N here.
1435
1436config KEXEC
1437	depends on PM_SLEEP_SMP
1438	select KEXEC_CORE
1439	bool "kexec system call"
1440	help
1441	  kexec is a system call that implements the ability to shutdown your
1442	  current kernel, and to start another kernel.  It is like a reboot
1443	  but it is independent of the system firmware.   And like a reboot
1444	  you can start any kernel with it, not just Linux.
1445
1446config KEXEC_FILE
1447	bool "kexec file based system call"
1448	select KEXEC_CORE
1449	select HAVE_IMA_KEXEC if IMA
1450	help
1451	  This is new version of kexec system call. This system call is
1452	  file based and takes file descriptors as system call argument
1453	  for kernel and initramfs as opposed to list of segments as
1454	  accepted by previous system call.
1455
1456config KEXEC_SIG
1457	bool "Verify kernel signature during kexec_file_load() syscall"
1458	depends on KEXEC_FILE
1459	help
1460	  Select this option to verify a signature with loaded kernel
1461	  image. If configured, any attempt of loading a image without
1462	  valid signature will fail.
1463
1464	  In addition to that option, you need to enable signature
1465	  verification for the corresponding kernel image type being
1466	  loaded in order for this to work.
1467
1468config KEXEC_IMAGE_VERIFY_SIG
1469	bool "Enable Image signature verification support"
1470	default y
1471	depends on KEXEC_SIG
1472	depends on EFI && SIGNED_PE_FILE_VERIFICATION
1473	help
1474	  Enable Image signature verification support.
1475
1476comment "Support for PE file signature verification disabled"
1477	depends on KEXEC_SIG
1478	depends on !EFI || !SIGNED_PE_FILE_VERIFICATION
1479
1480config CRASH_DUMP
1481	bool "Build kdump crash kernel"
1482	help
1483	  Generate crash dump after being started by kexec. This should
1484	  be normally only set in special crash dump kernels which are
1485	  loaded in the main kernel with kexec-tools into a specially
1486	  reserved region and then later executed after a crash by
1487	  kdump/kexec.
1488
1489	  For more details see Documentation/admin-guide/kdump/kdump.rst
1490
1491config TRANS_TABLE
1492	def_bool y
1493	depends on HIBERNATION || KEXEC_CORE
1494
1495config XEN_DOM0
1496	def_bool y
1497	depends on XEN
1498
1499config XEN
1500	bool "Xen guest support on ARM64"
1501	depends on ARM64 && OF
1502	select SWIOTLB_XEN
1503	select PARAVIRT
1504	help
1505	  Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64.
1506
1507# include/linux/mmzone.h requires the following to be true:
1508#
1509#   MAX_ORDER + PAGE_SHIFT <= SECTION_SIZE_BITS
1510#
1511# so the maximum value of MAX_ORDER is SECTION_SIZE_BITS - PAGE_SHIFT:
1512#
1513#     | SECTION_SIZE_BITS |  PAGE_SHIFT  |  max MAX_ORDER  |  default MAX_ORDER |
1514# ----+-------------------+--------------+-----------------+--------------------+
1515# 4K  |       27          |      12      |       15        |         10         |
1516# 16K |       27          |      14      |       13        |         11         |
1517# 64K |       29          |      16      |       13        |         13         |
1518config ARCH_FORCE_MAX_ORDER
1519	int "Order of maximal physically contiguous allocations" if EXPERT && (ARM64_4K_PAGES || ARM64_16K_PAGES)
1520	default "13" if ARM64_64K_PAGES
1521	default "11" if ARM64_16K_PAGES
1522	default "10"
1523	help
1524	  The kernel page allocator limits the size of maximal physically
1525	  contiguous allocations. The limit is called MAX_ORDER and it
1526	  defines the maximal power of two of number of pages that can be
1527	  allocated as a single contiguous block. This option allows
1528	  overriding the default setting when ability to allocate very
1529	  large blocks of physically contiguous memory is required.
1530
1531	  The maximal size of allocation cannot exceed the size of the
1532	  section, so the value of MAX_ORDER should satisfy
1533
1534	    MAX_ORDER + PAGE_SHIFT <= SECTION_SIZE_BITS
1535
1536	  Don't change if unsure.
1537
1538config UNMAP_KERNEL_AT_EL0
1539	bool "Unmap kernel when running in userspace (aka \"KAISER\")" if EXPERT
1540	default y
1541	help
1542	  Speculation attacks against some high-performance processors can
1543	  be used to bypass MMU permission checks and leak kernel data to
1544	  userspace. This can be defended against by unmapping the kernel
1545	  when running in userspace, mapping it back in on exception entry
1546	  via a trampoline page in the vector table.
1547
1548	  If unsure, say Y.
1549
1550config MITIGATE_SPECTRE_BRANCH_HISTORY
1551	bool "Mitigate Spectre style attacks against branch history" if EXPERT
1552	default y
1553	help
1554	  Speculation attacks against some high-performance processors can
1555	  make use of branch history to influence future speculation.
1556	  When taking an exception from user-space, a sequence of branches
1557	  or a firmware call overwrites the branch history.
1558
1559config RODATA_FULL_DEFAULT_ENABLED
1560	bool "Apply r/o permissions of VM areas also to their linear aliases"
1561	default y
1562	help
1563	  Apply read-only attributes of VM areas to the linear alias of
1564	  the backing pages as well. This prevents code or read-only data
1565	  from being modified (inadvertently or intentionally) via another
1566	  mapping of the same memory page. This additional enhancement can
1567	  be turned off at runtime by passing rodata=[off|on] (and turned on
1568	  with rodata=full if this option is set to 'n')
1569
1570	  This requires the linear region to be mapped down to pages,
1571	  which may adversely affect performance in some cases.
1572
1573config ARM64_SW_TTBR0_PAN
1574	bool "Emulate Privileged Access Never using TTBR0_EL1 switching"
1575	help
1576	  Enabling this option prevents the kernel from accessing
1577	  user-space memory directly by pointing TTBR0_EL1 to a reserved
1578	  zeroed area and reserved ASID. The user access routines
1579	  restore the valid TTBR0_EL1 temporarily.
1580
1581config ARM64_TAGGED_ADDR_ABI
1582	bool "Enable the tagged user addresses syscall ABI"
1583	default y
1584	help
1585	  When this option is enabled, user applications can opt in to a
1586	  relaxed ABI via prctl() allowing tagged addresses to be passed
1587	  to system calls as pointer arguments. For details, see
1588	  Documentation/arm64/tagged-address-abi.rst.
1589
1590menuconfig COMPAT
1591	bool "Kernel support for 32-bit EL0"
1592	depends on ARM64_4K_PAGES || EXPERT
1593	select HAVE_UID16
1594	select OLD_SIGSUSPEND3
1595	select COMPAT_OLD_SIGACTION
1596	help
1597	  This option enables support for a 32-bit EL0 running under a 64-bit
1598	  kernel at EL1. AArch32-specific components such as system calls,
1599	  the user helper functions, VFP support and the ptrace interface are
1600	  handled appropriately by the kernel.
1601
1602	  If you use a page size other than 4KB (i.e, 16KB or 64KB), please be aware
1603	  that you will only be able to execute AArch32 binaries that were compiled
1604	  with page size aligned segments.
1605
1606	  If you want to execute 32-bit userspace applications, say Y.
1607
1608if COMPAT
1609
1610config KUSER_HELPERS
1611	bool "Enable kuser helpers page for 32-bit applications"
1612	default y
1613	help
1614	  Warning: disabling this option may break 32-bit user programs.
1615
1616	  Provide kuser helpers to compat tasks. The kernel provides
1617	  helper code to userspace in read only form at a fixed location
1618	  to allow userspace to be independent of the CPU type fitted to
1619	  the system. This permits binaries to be run on ARMv4 through
1620	  to ARMv8 without modification.
1621
1622	  See Documentation/arm/kernel_user_helpers.rst for details.
1623
1624	  However, the fixed address nature of these helpers can be used
1625	  by ROP (return orientated programming) authors when creating
1626	  exploits.
1627
1628	  If all of the binaries and libraries which run on your platform
1629	  are built specifically for your platform, and make no use of
1630	  these helpers, then you can turn this option off to hinder
1631	  such exploits. However, in that case, if a binary or library
1632	  relying on those helpers is run, it will not function correctly.
1633
1634	  Say N here only if you are absolutely certain that you do not
1635	  need these helpers; otherwise, the safe option is to say Y.
1636
1637config COMPAT_VDSO
1638	bool "Enable vDSO for 32-bit applications"
1639	depends on !CPU_BIG_ENDIAN
1640	depends on (CC_IS_CLANG && LD_IS_LLD) || "$(CROSS_COMPILE_COMPAT)" != ""
1641	select GENERIC_COMPAT_VDSO
1642	default y
1643	help
1644	  Place in the process address space of 32-bit applications an
1645	  ELF shared object providing fast implementations of gettimeofday
1646	  and clock_gettime.
1647
1648	  You must have a 32-bit build of glibc 2.22 or later for programs
1649	  to seamlessly take advantage of this.
1650
1651config THUMB2_COMPAT_VDSO
1652	bool "Compile the 32-bit vDSO for Thumb-2 mode" if EXPERT
1653	depends on COMPAT_VDSO
1654	default y
1655	help
1656	  Compile the compat vDSO with '-mthumb -fomit-frame-pointer' if y,
1657	  otherwise with '-marm'.
1658
1659config COMPAT_ALIGNMENT_FIXUPS
1660	bool "Fix up misaligned multi-word loads and stores in user space"
1661
1662menuconfig ARMV8_DEPRECATED
1663	bool "Emulate deprecated/obsolete ARMv8 instructions"
1664	depends on SYSCTL
1665	help
1666	  Legacy software support may require certain instructions
1667	  that have been deprecated or obsoleted in the architecture.
1668
1669	  Enable this config to enable selective emulation of these
1670	  features.
1671
1672	  If unsure, say Y
1673
1674if ARMV8_DEPRECATED
1675
1676config SWP_EMULATION
1677	bool "Emulate SWP/SWPB instructions"
1678	help
1679	  ARMv8 obsoletes the use of A32 SWP/SWPB instructions such that
1680	  they are always undefined. Say Y here to enable software
1681	  emulation of these instructions for userspace using LDXR/STXR.
1682	  This feature can be controlled at runtime with the abi.swp
1683	  sysctl which is disabled by default.
1684
1685	  In some older versions of glibc [<=2.8] SWP is used during futex
1686	  trylock() operations with the assumption that the code will not
1687	  be preempted. This invalid assumption may be more likely to fail
1688	  with SWP emulation enabled, leading to deadlock of the user
1689	  application.
1690
1691	  NOTE: when accessing uncached shared regions, LDXR/STXR rely
1692	  on an external transaction monitoring block called a global
1693	  monitor to maintain update atomicity. If your system does not
1694	  implement a global monitor, this option can cause programs that
1695	  perform SWP operations to uncached memory to deadlock.
1696
1697	  If unsure, say Y
1698
1699config CP15_BARRIER_EMULATION
1700	bool "Emulate CP15 Barrier instructions"
1701	help
1702	  The CP15 barrier instructions - CP15ISB, CP15DSB, and
1703	  CP15DMB - are deprecated in ARMv8 (and ARMv7). It is
1704	  strongly recommended to use the ISB, DSB, and DMB
1705	  instructions instead.
1706
1707	  Say Y here to enable software emulation of these
1708	  instructions for AArch32 userspace code. When this option is
1709	  enabled, CP15 barrier usage is traced which can help
1710	  identify software that needs updating. This feature can be
1711	  controlled at runtime with the abi.cp15_barrier sysctl.
1712
1713	  If unsure, say Y
1714
1715config SETEND_EMULATION
1716	bool "Emulate SETEND instruction"
1717	help
1718	  The SETEND instruction alters the data-endianness of the
1719	  AArch32 EL0, and is deprecated in ARMv8.
1720
1721	  Say Y here to enable software emulation of the instruction
1722	  for AArch32 userspace code. This feature can be controlled
1723	  at runtime with the abi.setend sysctl.
1724
1725	  Note: All the cpus on the system must have mixed endian support at EL0
1726	  for this feature to be enabled. If a new CPU - which doesn't support mixed
1727	  endian - is hotplugged in after this feature has been enabled, there could
1728	  be unexpected results in the applications.
1729
1730	  If unsure, say Y
1731endif # ARMV8_DEPRECATED
1732
1733endif # COMPAT
1734
1735menu "ARMv8.1 architectural features"
1736
1737config ARM64_HW_AFDBM
1738	bool "Support for hardware updates of the Access and Dirty page flags"
1739	default y
1740	help
1741	  The ARMv8.1 architecture extensions introduce support for
1742	  hardware updates of the access and dirty information in page
1743	  table entries. When enabled in TCR_EL1 (HA and HD bits) on
1744	  capable processors, accesses to pages with PTE_AF cleared will
1745	  set this bit instead of raising an access flag fault.
1746	  Similarly, writes to read-only pages with the DBM bit set will
1747	  clear the read-only bit (AP[2]) instead of raising a
1748	  permission fault.
1749
1750	  Kernels built with this configuration option enabled continue
1751	  to work on pre-ARMv8.1 hardware and the performance impact is
1752	  minimal. If unsure, say Y.
1753
1754config ARM64_PAN
1755	bool "Enable support for Privileged Access Never (PAN)"
1756	default y
1757	help
1758	  Privileged Access Never (PAN; part of the ARMv8.1 Extensions)
1759	  prevents the kernel or hypervisor from accessing user-space (EL0)
1760	  memory directly.
1761
1762	  Choosing this option will cause any unprotected (not using
1763	  copy_to_user et al) memory access to fail with a permission fault.
1764
1765	  The feature is detected at runtime, and will remain as a 'nop'
1766	  instruction if the cpu does not implement the feature.
1767
1768config AS_HAS_LDAPR
1769	def_bool $(as-instr,.arch_extension rcpc)
1770
1771config AS_HAS_LSE_ATOMICS
1772	def_bool $(as-instr,.arch_extension lse)
1773
1774config ARM64_LSE_ATOMICS
1775	bool
1776	default ARM64_USE_LSE_ATOMICS
1777	depends on AS_HAS_LSE_ATOMICS
1778
1779config ARM64_USE_LSE_ATOMICS
1780	bool "Atomic instructions"
1781	default y
1782	help
1783	  As part of the Large System Extensions, ARMv8.1 introduces new
1784	  atomic instructions that are designed specifically to scale in
1785	  very large systems.
1786
1787	  Say Y here to make use of these instructions for the in-kernel
1788	  atomic routines. This incurs a small overhead on CPUs that do
1789	  not support these instructions and requires the kernel to be
1790	  built with binutils >= 2.25 in order for the new instructions
1791	  to be used.
1792
1793endmenu # "ARMv8.1 architectural features"
1794
1795menu "ARMv8.2 architectural features"
1796
1797config AS_HAS_ARMV8_2
1798	def_bool $(cc-option,-Wa$(comma)-march=armv8.2-a)
1799
1800config AS_HAS_SHA3
1801	def_bool $(as-instr,.arch armv8.2-a+sha3)
1802
1803config ARM64_PMEM
1804	bool "Enable support for persistent memory"
1805	select ARCH_HAS_PMEM_API
1806	select ARCH_HAS_UACCESS_FLUSHCACHE
1807	help
1808	  Say Y to enable support for the persistent memory API based on the
1809	  ARMv8.2 DCPoP feature.
1810
1811	  The feature is detected at runtime, and the kernel will use DC CVAC
1812	  operations if DC CVAP is not supported (following the behaviour of
1813	  DC CVAP itself if the system does not define a point of persistence).
1814
1815config ARM64_RAS_EXTN
1816	bool "Enable support for RAS CPU Extensions"
1817	default y
1818	help
1819	  CPUs that support the Reliability, Availability and Serviceability
1820	  (RAS) Extensions, part of ARMv8.2 are able to track faults and
1821	  errors, classify them and report them to software.
1822
1823	  On CPUs with these extensions system software can use additional
1824	  barriers to determine if faults are pending and read the
1825	  classification from a new set of registers.
1826
1827	  Selecting this feature will allow the kernel to use these barriers
1828	  and access the new registers if the system supports the extension.
1829	  Platform RAS features may additionally depend on firmware support.
1830
1831config ARM64_CNP
1832	bool "Enable support for Common Not Private (CNP) translations"
1833	default y
1834	depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
1835	help
1836	  Common Not Private (CNP) allows translation table entries to
1837	  be shared between different PEs in the same inner shareable
1838	  domain, so the hardware can use this fact to optimise the
1839	  caching of such entries in the TLB.
1840
1841	  Selecting this option allows the CNP feature to be detected
1842	  at runtime, and does not affect PEs that do not implement
1843	  this feature.
1844
1845endmenu # "ARMv8.2 architectural features"
1846
1847menu "ARMv8.3 architectural features"
1848
1849config ARM64_PTR_AUTH
1850	bool "Enable support for pointer authentication"
1851	default y
1852	help
1853	  Pointer authentication (part of the ARMv8.3 Extensions) provides
1854	  instructions for signing and authenticating pointers against secret
1855	  keys, which can be used to mitigate Return Oriented Programming (ROP)
1856	  and other attacks.
1857
1858	  This option enables these instructions at EL0 (i.e. for userspace).
1859	  Choosing this option will cause the kernel to initialise secret keys
1860	  for each process at exec() time, with these keys being
1861	  context-switched along with the process.
1862
1863	  The feature is detected at runtime. If the feature is not present in
1864	  hardware it will not be advertised to userspace/KVM guest nor will it
1865	  be enabled.
1866
1867	  If the feature is present on the boot CPU but not on a late CPU, then
1868	  the late CPU will be parked. Also, if the boot CPU does not have
1869	  address auth and the late CPU has then the late CPU will still boot
1870	  but with the feature disabled. On such a system, this option should
1871	  not be selected.
1872
1873config ARM64_PTR_AUTH_KERNEL
1874	bool "Use pointer authentication for kernel"
1875	default y
1876	depends on ARM64_PTR_AUTH
1877	depends on (CC_HAS_SIGN_RETURN_ADDRESS || CC_HAS_BRANCH_PROT_PAC_RET) && AS_HAS_ARMV8_3
1878	# Modern compilers insert a .note.gnu.property section note for PAC
1879	# which is only understood by binutils starting with version 2.33.1.
1880	depends on LD_IS_LLD || LD_VERSION >= 23301 || (CC_IS_GCC && GCC_VERSION < 90100)
1881	depends on !CC_IS_CLANG || AS_HAS_CFI_NEGATE_RA_STATE
1882	depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_ARGS)
1883	help
1884	  If the compiler supports the -mbranch-protection or
1885	  -msign-return-address flag (e.g. GCC 7 or later), then this option
1886	  will cause the kernel itself to be compiled with return address
1887	  protection. In this case, and if the target hardware is known to
1888	  support pointer authentication, then CONFIG_STACKPROTECTOR can be
1889	  disabled with minimal loss of protection.
1890
1891	  This feature works with FUNCTION_GRAPH_TRACER option only if
1892	  DYNAMIC_FTRACE_WITH_ARGS is enabled.
1893
1894config CC_HAS_BRANCH_PROT_PAC_RET
1895	# GCC 9 or later, clang 8 or later
1896	def_bool $(cc-option,-mbranch-protection=pac-ret+leaf)
1897
1898config CC_HAS_SIGN_RETURN_ADDRESS
1899	# GCC 7, 8
1900	def_bool $(cc-option,-msign-return-address=all)
1901
1902config AS_HAS_ARMV8_3
1903	def_bool $(cc-option,-Wa$(comma)-march=armv8.3-a)
1904
1905config AS_HAS_CFI_NEGATE_RA_STATE
1906	def_bool $(as-instr,.cfi_startproc\n.cfi_negate_ra_state\n.cfi_endproc\n)
1907
1908endmenu # "ARMv8.3 architectural features"
1909
1910menu "ARMv8.4 architectural features"
1911
1912config ARM64_AMU_EXTN
1913	bool "Enable support for the Activity Monitors Unit CPU extension"
1914	default y
1915	help
1916	  The activity monitors extension is an optional extension introduced
1917	  by the ARMv8.4 CPU architecture. This enables support for version 1
1918	  of the activity monitors architecture, AMUv1.
1919
1920	  To enable the use of this extension on CPUs that implement it, say Y.
1921
1922	  Note that for architectural reasons, firmware _must_ implement AMU
1923	  support when running on CPUs that present the activity monitors
1924	  extension. The required support is present in:
1925	    * Version 1.5 and later of the ARM Trusted Firmware
1926
1927	  For kernels that have this configuration enabled but boot with broken
1928	  firmware, you may need to say N here until the firmware is fixed.
1929	  Otherwise you may experience firmware panics or lockups when
1930	  accessing the counter registers. Even if you are not observing these
1931	  symptoms, the values returned by the register reads might not
1932	  correctly reflect reality. Most commonly, the value read will be 0,
1933	  indicating that the counter is not enabled.
1934
1935config AS_HAS_ARMV8_4
1936	def_bool $(cc-option,-Wa$(comma)-march=armv8.4-a)
1937
1938config ARM64_TLB_RANGE
1939	bool "Enable support for tlbi range feature"
1940	default y
1941	depends on AS_HAS_ARMV8_4
1942	help
1943	  ARMv8.4-TLBI provides TLBI invalidation instruction that apply to a
1944	  range of input addresses.
1945
1946	  The feature introduces new assembly instructions, and they were
1947	  support when binutils >= 2.30.
1948
1949endmenu # "ARMv8.4 architectural features"
1950
1951menu "ARMv8.5 architectural features"
1952
1953config AS_HAS_ARMV8_5
1954	def_bool $(cc-option,-Wa$(comma)-march=armv8.5-a)
1955
1956config ARM64_BTI
1957	bool "Branch Target Identification support"
1958	default y
1959	help
1960	  Branch Target Identification (part of the ARMv8.5 Extensions)
1961	  provides a mechanism to limit the set of locations to which computed
1962	  branch instructions such as BR or BLR can jump.
1963
1964	  To make use of BTI on CPUs that support it, say Y.
1965
1966	  BTI is intended to provide complementary protection to other control
1967	  flow integrity protection mechanisms, such as the Pointer
1968	  authentication mechanism provided as part of the ARMv8.3 Extensions.
1969	  For this reason, it does not make sense to enable this option without
1970	  also enabling support for pointer authentication.  Thus, when
1971	  enabling this option you should also select ARM64_PTR_AUTH=y.
1972
1973	  Userspace binaries must also be specifically compiled to make use of
1974	  this mechanism.  If you say N here or the hardware does not support
1975	  BTI, such binaries can still run, but you get no additional
1976	  enforcement of branch destinations.
1977
1978config ARM64_BTI_KERNEL
1979	bool "Use Branch Target Identification for kernel"
1980	default y
1981	depends on ARM64_BTI
1982	depends on ARM64_PTR_AUTH_KERNEL
1983	depends on CC_HAS_BRANCH_PROT_PAC_RET_BTI
1984	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94697
1985	depends on !CC_IS_GCC || GCC_VERSION >= 100100
1986	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106671
1987	depends on !CC_IS_GCC
1988	# https://github.com/llvm/llvm-project/commit/a88c722e687e6780dcd6a58718350dc76fcc4cc9
1989	depends on !CC_IS_CLANG || CLANG_VERSION >= 120000
1990	depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_ARGS)
1991	help
1992	  Build the kernel with Branch Target Identification annotations
1993	  and enable enforcement of this for kernel code. When this option
1994	  is enabled and the system supports BTI all kernel code including
1995	  modular code must have BTI enabled.
1996
1997config CC_HAS_BRANCH_PROT_PAC_RET_BTI
1998	# GCC 9 or later, clang 8 or later
1999	def_bool $(cc-option,-mbranch-protection=pac-ret+leaf+bti)
2000
2001config ARM64_E0PD
2002	bool "Enable support for E0PD"
2003	default y
2004	help
2005	  E0PD (part of the ARMv8.5 extensions) allows us to ensure
2006	  that EL0 accesses made via TTBR1 always fault in constant time,
2007	  providing similar benefits to KASLR as those provided by KPTI, but
2008	  with lower overhead and without disrupting legitimate access to
2009	  kernel memory such as SPE.
2010
2011	  This option enables E0PD for TTBR1 where available.
2012
2013config ARM64_AS_HAS_MTE
2014	# Initial support for MTE went in binutils 2.32.0, checked with
2015	# ".arch armv8.5-a+memtag" below. However, this was incomplete
2016	# as a late addition to the final architecture spec (LDGM/STGM)
2017	# is only supported in the newer 2.32.x and 2.33 binutils
2018	# versions, hence the extra "stgm" instruction check below.
2019	def_bool $(as-instr,.arch armv8.5-a+memtag\nstgm xzr$(comma)[x0])
2020
2021config ARM64_MTE
2022	bool "Memory Tagging Extension support"
2023	default y
2024	depends on ARM64_AS_HAS_MTE && ARM64_TAGGED_ADDR_ABI
2025	depends on AS_HAS_ARMV8_5
2026	depends on AS_HAS_LSE_ATOMICS
2027	# Required for tag checking in the uaccess routines
2028	depends on ARM64_PAN
2029	select ARCH_HAS_SUBPAGE_FAULTS
2030	select ARCH_USES_HIGH_VMA_FLAGS
2031	select ARCH_USES_PG_ARCH_X
2032	help
2033	  Memory Tagging (part of the ARMv8.5 Extensions) provides
2034	  architectural support for run-time, always-on detection of
2035	  various classes of memory error to aid with software debugging
2036	  to eliminate vulnerabilities arising from memory-unsafe
2037	  languages.
2038
2039	  This option enables the support for the Memory Tagging
2040	  Extension at EL0 (i.e. for userspace).
2041
2042	  Selecting this option allows the feature to be detected at
2043	  runtime. Any secondary CPU not implementing this feature will
2044	  not be allowed a late bring-up.
2045
2046	  Userspace binaries that want to use this feature must
2047	  explicitly opt in. The mechanism for the userspace is
2048	  described in:
2049
2050	  Documentation/arm64/memory-tagging-extension.rst.
2051
2052endmenu # "ARMv8.5 architectural features"
2053
2054menu "ARMv8.7 architectural features"
2055
2056config ARM64_EPAN
2057	bool "Enable support for Enhanced Privileged Access Never (EPAN)"
2058	default y
2059	depends on ARM64_PAN
2060	help
2061	  Enhanced Privileged Access Never (EPAN) allows Privileged
2062	  Access Never to be used with Execute-only mappings.
2063
2064	  The feature is detected at runtime, and will remain disabled
2065	  if the cpu does not implement the feature.
2066endmenu # "ARMv8.7 architectural features"
2067
2068config ARM64_SVE
2069	bool "ARM Scalable Vector Extension support"
2070	default y
2071	help
2072	  The Scalable Vector Extension (SVE) is an extension to the AArch64
2073	  execution state which complements and extends the SIMD functionality
2074	  of the base architecture to support much larger vectors and to enable
2075	  additional vectorisation opportunities.
2076
2077	  To enable use of this extension on CPUs that implement it, say Y.
2078
2079	  On CPUs that support the SVE2 extensions, this option will enable
2080	  those too.
2081
2082	  Note that for architectural reasons, firmware _must_ implement SVE
2083	  support when running on SVE capable hardware.  The required support
2084	  is present in:
2085
2086	    * version 1.5 and later of the ARM Trusted Firmware
2087	    * the AArch64 boot wrapper since commit 5e1261e08abf
2088	      ("bootwrapper: SVE: Enable SVE for EL2 and below").
2089
2090	  For other firmware implementations, consult the firmware documentation
2091	  or vendor.
2092
2093	  If you need the kernel to boot on SVE-capable hardware with broken
2094	  firmware, you may need to say N here until you get your firmware
2095	  fixed.  Otherwise, you may experience firmware panics or lockups when
2096	  booting the kernel.  If unsure and you are not observing these
2097	  symptoms, you should assume that it is safe to say Y.
2098
2099config ARM64_SME
2100	bool "ARM Scalable Matrix Extension support"
2101	default y
2102	depends on ARM64_SVE
2103	help
2104	  The Scalable Matrix Extension (SME) is an extension to the AArch64
2105	  execution state which utilises a substantial subset of the SVE
2106	  instruction set, together with the addition of new architectural
2107	  register state capable of holding two dimensional matrix tiles to
2108	  enable various matrix operations.
2109
2110config ARM64_MODULE_PLTS
2111	bool "Use PLTs to allow module memory to spill over into vmalloc area"
2112	depends on MODULES
2113	select HAVE_MOD_ARCH_SPECIFIC
2114	help
2115	  Allocate PLTs when loading modules so that jumps and calls whose
2116	  targets are too far away for their relative offsets to be encoded
2117	  in the instructions themselves can be bounced via veneers in the
2118	  module's PLT. This allows modules to be allocated in the generic
2119	  vmalloc area after the dedicated module memory area has been
2120	  exhausted.
2121
2122	  When running with address space randomization (KASLR), the module
2123	  region itself may be too far away for ordinary relative jumps and
2124	  calls, and so in that case, module PLTs are required and cannot be
2125	  disabled.
2126
2127	  Specific errata workaround(s) might also force module PLTs to be
2128	  enabled (ARM64_ERRATUM_843419).
2129
2130config ARM64_PSEUDO_NMI
2131	bool "Support for NMI-like interrupts"
2132	select ARM_GIC_V3
2133	help
2134	  Adds support for mimicking Non-Maskable Interrupts through the use of
2135	  GIC interrupt priority. This support requires version 3 or later of
2136	  ARM GIC.
2137
2138	  This high priority configuration for interrupts needs to be
2139	  explicitly enabled by setting the kernel parameter
2140	  "irqchip.gicv3_pseudo_nmi" to 1.
2141
2142	  If unsure, say N
2143
2144if ARM64_PSEUDO_NMI
2145config ARM64_DEBUG_PRIORITY_MASKING
2146	bool "Debug interrupt priority masking"
2147	help
2148	  This adds runtime checks to functions enabling/disabling
2149	  interrupts when using priority masking. The additional checks verify
2150	  the validity of ICC_PMR_EL1 when calling concerned functions.
2151
2152	  If unsure, say N
2153endif # ARM64_PSEUDO_NMI
2154
2155config RELOCATABLE
2156	bool "Build a relocatable kernel image" if EXPERT
2157	select ARCH_HAS_RELR
2158	default y
2159	help
2160	  This builds the kernel as a Position Independent Executable (PIE),
2161	  which retains all relocation metadata required to relocate the
2162	  kernel binary at runtime to a different virtual address than the
2163	  address it was linked at.
2164	  Since AArch64 uses the RELA relocation format, this requires a
2165	  relocation pass at runtime even if the kernel is loaded at the
2166	  same address it was linked at.
2167
2168config RANDOMIZE_BASE
2169	bool "Randomize the address of the kernel image"
2170	select ARM64_MODULE_PLTS if MODULES
2171	select RELOCATABLE
2172	help
2173	  Randomizes the virtual address at which the kernel image is
2174	  loaded, as a security feature that deters exploit attempts
2175	  relying on knowledge of the location of kernel internals.
2176
2177	  It is the bootloader's job to provide entropy, by passing a
2178	  random u64 value in /chosen/kaslr-seed at kernel entry.
2179
2180	  When booting via the UEFI stub, it will invoke the firmware's
2181	  EFI_RNG_PROTOCOL implementation (if available) to supply entropy
2182	  to the kernel proper. In addition, it will randomise the physical
2183	  location of the kernel Image as well.
2184
2185	  If unsure, say N.
2186
2187config RANDOMIZE_MODULE_REGION_FULL
2188	bool "Randomize the module region over a 2 GB range"
2189	depends on RANDOMIZE_BASE
2190	default y
2191	help
2192	  Randomizes the location of the module region inside a 2 GB window
2193	  covering the core kernel. This way, it is less likely for modules
2194	  to leak information about the location of core kernel data structures
2195	  but it does imply that function calls between modules and the core
2196	  kernel will need to be resolved via veneers in the module PLT.
2197
2198	  When this option is not set, the module region will be randomized over
2199	  a limited range that contains the [_stext, _etext] interval of the
2200	  core kernel, so branch relocations are almost always in range unless
2201	  ARM64_MODULE_PLTS is enabled and the region is exhausted. In this
2202	  particular case of region exhaustion, modules might be able to fall
2203	  back to a larger 2GB area.
2204
2205config CC_HAVE_STACKPROTECTOR_SYSREG
2206	def_bool $(cc-option,-mstack-protector-guard=sysreg -mstack-protector-guard-reg=sp_el0 -mstack-protector-guard-offset=0)
2207
2208config STACKPROTECTOR_PER_TASK
2209	def_bool y
2210	depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_SYSREG
2211
2212config UNWIND_PATCH_PAC_INTO_SCS
2213	bool "Enable shadow call stack dynamically using code patching"
2214	# needs Clang with https://reviews.llvm.org/D111780 incorporated
2215	depends on CC_IS_CLANG && CLANG_VERSION >= 150000
2216	depends on ARM64_PTR_AUTH_KERNEL && CC_HAS_BRANCH_PROT_PAC_RET
2217	depends on SHADOW_CALL_STACK
2218	select UNWIND_TABLES
2219	select DYNAMIC_SCS
2220
2221endmenu # "Kernel Features"
2222
2223menu "Boot options"
2224
2225config ARM64_ACPI_PARKING_PROTOCOL
2226	bool "Enable support for the ARM64 ACPI parking protocol"
2227	depends on ACPI
2228	help
2229	  Enable support for the ARM64 ACPI parking protocol. If disabled
2230	  the kernel will not allow booting through the ARM64 ACPI parking
2231	  protocol even if the corresponding data is present in the ACPI
2232	  MADT table.
2233
2234config CMDLINE
2235	string "Default kernel command string"
2236	default ""
2237	help
2238	  Provide a set of default command-line options at build time by
2239	  entering them here. As a minimum, you should specify the the
2240	  root device (e.g. root=/dev/nfs).
2241
2242choice
2243	prompt "Kernel command line type" if CMDLINE != ""
2244	default CMDLINE_FROM_BOOTLOADER
2245	help
2246	  Choose how the kernel will handle the provided default kernel
2247	  command line string.
2248
2249config CMDLINE_FROM_BOOTLOADER
2250	bool "Use bootloader kernel arguments if available"
2251	help
2252	  Uses the command-line options passed by the boot loader. If
2253	  the boot loader doesn't provide any, the default kernel command
2254	  string provided in CMDLINE will be used.
2255
2256config CMDLINE_FORCE
2257	bool "Always use the default kernel command string"
2258	help
2259	  Always use the default kernel command string, even if the boot
2260	  loader passes other arguments to the kernel.
2261	  This is useful if you cannot or don't want to change the
2262	  command-line options your boot loader passes to the kernel.
2263
2264endchoice
2265
2266config EFI_STUB
2267	bool
2268
2269config EFI
2270	bool "UEFI runtime support"
2271	depends on OF && !CPU_BIG_ENDIAN
2272	depends on KERNEL_MODE_NEON
2273	select ARCH_SUPPORTS_ACPI
2274	select LIBFDT
2275	select UCS2_STRING
2276	select EFI_PARAMS_FROM_FDT
2277	select EFI_RUNTIME_WRAPPERS
2278	select EFI_STUB
2279	select EFI_GENERIC_STUB
2280	imply IMA_SECURE_AND_OR_TRUSTED_BOOT
2281	default y
2282	help
2283	  This option provides support for runtime services provided
2284	  by UEFI firmware (such as non-volatile variables, realtime
2285	  clock, and platform reset). A UEFI stub is also provided to
2286	  allow the kernel to be booted as an EFI application. This
2287	  is only useful on systems that have UEFI firmware.
2288
2289config DMI
2290	bool "Enable support for SMBIOS (DMI) tables"
2291	depends on EFI
2292	default y
2293	help
2294	  This enables SMBIOS/DMI feature for systems.
2295
2296	  This option is only useful on systems that have UEFI firmware.
2297	  However, even with this option, the resultant kernel should
2298	  continue to boot on existing non-UEFI platforms.
2299
2300endmenu # "Boot options"
2301
2302menu "Power management options"
2303
2304source "kernel/power/Kconfig"
2305
2306config ARCH_HIBERNATION_POSSIBLE
2307	def_bool y
2308	depends on CPU_PM
2309
2310config ARCH_HIBERNATION_HEADER
2311	def_bool y
2312	depends on HIBERNATION
2313
2314config ARCH_SUSPEND_POSSIBLE
2315	def_bool y
2316
2317endmenu # "Power management options"
2318
2319menu "CPU Power Management"
2320
2321source "drivers/cpuidle/Kconfig"
2322
2323source "drivers/cpufreq/Kconfig"
2324
2325endmenu # "CPU Power Management"
2326
2327source "drivers/acpi/Kconfig"
2328
2329source "arch/arm64/kvm/Kconfig"
2330
2331