xref: /openbmc/linux/arch/arm64/Kconfig (revision 4c004ed9)
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_MHP_MEMMAP_ON_MEMORY_ENABLE
82	select ARCH_USE_CMPXCHG_LOCKREF
83	select ARCH_USE_GNU_PROPERTY
84	select ARCH_USE_MEMTEST
85	select ARCH_USE_QUEUED_RWLOCKS
86	select ARCH_USE_QUEUED_SPINLOCKS
87	select ARCH_USE_SYM_ANNOTATIONS
88	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
89	select ARCH_SUPPORTS_HUGETLBFS
90	select ARCH_SUPPORTS_MEMORY_FAILURE
91	select ARCH_SUPPORTS_SHADOW_CALL_STACK if CC_HAVE_SHADOW_CALL_STACK
92	select ARCH_SUPPORTS_LTO_CLANG if CPU_LITTLE_ENDIAN
93	select ARCH_SUPPORTS_LTO_CLANG_THIN
94	select ARCH_SUPPORTS_CFI_CLANG
95	select ARCH_SUPPORTS_ATOMIC_RMW
96	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
97	select ARCH_SUPPORTS_NUMA_BALANCING
98	select ARCH_SUPPORTS_PAGE_TABLE_CHECK
99	select ARCH_SUPPORTS_PER_VMA_LOCK
100	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
101	select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT
102	select ARCH_WANT_DEFAULT_BPF_JIT
103	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
104	select ARCH_WANT_FRAME_POINTERS
105	select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
106	select ARCH_WANT_LD_ORPHAN_WARN
107	select ARCH_WANTS_NO_INSTR
108	select ARCH_WANTS_THP_SWAP if ARM64_4K_PAGES
109	select ARCH_HAS_UBSAN_SANITIZE_ALL
110	select ARM_AMBA
111	select ARM_ARCH_TIMER
112	select ARM_GIC
113	select AUDIT_ARCH_COMPAT_GENERIC
114	select ARM_GIC_V2M if PCI
115	select ARM_GIC_V3
116	select ARM_GIC_V3_ITS if PCI
117	select ARM_PSCI_FW
118	select BUILDTIME_TABLE_SORT
119	select CLONE_BACKWARDS
120	select COMMON_CLK
121	select CPU_PM if (SUSPEND || CPU_IDLE)
122	select CRC32
123	select DCACHE_WORD_ACCESS
124	select DYNAMIC_FTRACE if FUNCTION_TRACER
125	select DMA_BOUNCE_UNALIGNED_KMALLOC
126	select DMA_DIRECT_REMAP
127	select EDAC_SUPPORT
128	select FRAME_POINTER
129	select FUNCTION_ALIGNMENT_4B
130	select FUNCTION_ALIGNMENT_8B if DYNAMIC_FTRACE_WITH_CALL_OPS
131	select GENERIC_ALLOCATOR
132	select GENERIC_ARCH_TOPOLOGY
133	select GENERIC_CLOCKEVENTS_BROADCAST
134	select GENERIC_CPU_AUTOPROBE
135	select GENERIC_CPU_VULNERABILITIES
136	select GENERIC_EARLY_IOREMAP
137	select GENERIC_IDLE_POLL_SETUP
138	select GENERIC_IOREMAP
139	select GENERIC_IRQ_IPI
140	select GENERIC_IRQ_PROBE
141	select GENERIC_IRQ_SHOW
142	select GENERIC_IRQ_SHOW_LEVEL
143	select GENERIC_LIB_DEVMEM_IS_ALLOWED
144	select GENERIC_PCI_IOMAP
145	select GENERIC_PTDUMP
146	select GENERIC_SCHED_CLOCK
147	select GENERIC_SMP_IDLE_THREAD
148	select GENERIC_TIME_VSYSCALL
149	select GENERIC_GETTIMEOFDAY
150	select GENERIC_VDSO_TIME_NS
151	select HARDIRQS_SW_RESEND
152	select HAS_IOPORT
153	select HAVE_MOVE_PMD
154	select HAVE_MOVE_PUD
155	select HAVE_PCI
156	select HAVE_ACPI_APEI if (ACPI && EFI)
157	select HAVE_ALIGNED_STRUCT_PAGE if SLUB
158	select HAVE_ARCH_AUDITSYSCALL
159	select HAVE_ARCH_BITREVERSE
160	select HAVE_ARCH_COMPILER_H
161	select HAVE_ARCH_HUGE_VMALLOC
162	select HAVE_ARCH_HUGE_VMAP
163	select HAVE_ARCH_JUMP_LABEL
164	select HAVE_ARCH_JUMP_LABEL_RELATIVE
165	select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48)
166	select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN
167	select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN
168	select HAVE_ARCH_KASAN_HW_TAGS if (HAVE_ARCH_KASAN && ARM64_MTE)
169	# Some instrumentation may be unsound, hence EXPERT
170	select HAVE_ARCH_KCSAN if EXPERT
171	select HAVE_ARCH_KFENCE
172	select HAVE_ARCH_KGDB
173	select HAVE_ARCH_MMAP_RND_BITS
174	select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
175	select HAVE_ARCH_PREL32_RELOCATIONS
176	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
177	select HAVE_ARCH_SECCOMP_FILTER
178	select HAVE_ARCH_STACKLEAK
179	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
180	select HAVE_ARCH_TRACEHOOK
181	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
182	select HAVE_ARCH_VMAP_STACK
183	select HAVE_ARM_SMCCC
184	select HAVE_ASM_MODVERSIONS
185	select HAVE_EBPF_JIT
186	select HAVE_C_RECORDMCOUNT
187	select HAVE_CMPXCHG_DOUBLE
188	select HAVE_CMPXCHG_LOCAL
189	select HAVE_CONTEXT_TRACKING_USER
190	select HAVE_DEBUG_KMEMLEAK
191	select HAVE_DMA_CONTIGUOUS
192	select HAVE_DYNAMIC_FTRACE
193	select HAVE_DYNAMIC_FTRACE_WITH_ARGS \
194		if $(cc-option,-fpatchable-function-entry=2)
195	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS \
196		if DYNAMIC_FTRACE_WITH_ARGS && DYNAMIC_FTRACE_WITH_CALL_OPS
197	select HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS \
198		if (DYNAMIC_FTRACE_WITH_ARGS && !CFI_CLANG && \
199		    !CC_OPTIMIZE_FOR_SIZE)
200	select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY \
201		if DYNAMIC_FTRACE_WITH_ARGS
202	select HAVE_SAMPLE_FTRACE_DIRECT
203	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI
204	select HAVE_EFFICIENT_UNALIGNED_ACCESS
205	select HAVE_FAST_GUP
206	select HAVE_FTRACE_MCOUNT_RECORD
207	select HAVE_FUNCTION_TRACER
208	select HAVE_FUNCTION_ERROR_INJECTION
209	select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER
210	select HAVE_FUNCTION_GRAPH_TRACER
211	select HAVE_GCC_PLUGINS
212	select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && \
213		HW_PERF_EVENTS && HAVE_PERF_EVENTS_NMI
214	select HAVE_HW_BREAKPOINT if PERF_EVENTS
215	select HAVE_IOREMAP_PROT
216	select HAVE_IRQ_TIME_ACCOUNTING
217	select HAVE_KVM
218	select HAVE_MOD_ARCH_SPECIFIC
219	select HAVE_NMI
220	select HAVE_PERF_EVENTS
221	select HAVE_PERF_EVENTS_NMI if ARM64_PSEUDO_NMI
222	select HAVE_PERF_REGS
223	select HAVE_PERF_USER_STACK_DUMP
224	select HAVE_PREEMPT_DYNAMIC_KEY
225	select HAVE_REGS_AND_STACK_ACCESS_API
226	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
227	select HAVE_FUNCTION_ARG_ACCESS_API
228	select MMU_GATHER_RCU_TABLE_FREE
229	select HAVE_RSEQ
230	select HAVE_STACKPROTECTOR
231	select HAVE_SYSCALL_TRACEPOINTS
232	select HAVE_KPROBES
233	select HAVE_KRETPROBES
234	select HAVE_GENERIC_VDSO
235	select HOTPLUG_CORE_SYNC_DEAD if HOTPLUG_CPU
236	select IRQ_DOMAIN
237	select IRQ_FORCED_THREADING
238	select KASAN_VMALLOC if KASAN
239	select LOCK_MM_AND_FIND_VMA
240	select MODULES_USE_ELF_RELA
241	select NEED_DMA_MAP_STATE
242	select NEED_SG_DMA_LENGTH
243	select OF
244	select OF_EARLY_FLATTREE
245	select PCI_DOMAINS_GENERIC if PCI
246	select PCI_ECAM if (ACPI && PCI)
247	select PCI_SYSCALL if PCI
248	select POWER_RESET
249	select POWER_SUPPLY
250	select SPARSE_IRQ
251	select SWIOTLB
252	select SYSCTL_EXCEPTION_TRACE
253	select THREAD_INFO_IN_TASK
254	select HAVE_ARCH_USERFAULTFD_MINOR if USERFAULTFD
255	select TRACE_IRQFLAGS_SUPPORT
256	select TRACE_IRQFLAGS_NMI_SUPPORT
257	select HAVE_SOFTIRQ_ON_OWN_STACK
258	help
259	  ARM 64-bit (AArch64) Linux support.
260
261config CLANG_SUPPORTS_DYNAMIC_FTRACE_WITH_ARGS
262	def_bool CC_IS_CLANG
263	# https://github.com/ClangBuiltLinux/linux/issues/1507
264	depends on AS_IS_GNU || (AS_IS_LLVM && (LD_IS_LLD || LD_VERSION >= 23600))
265	select HAVE_DYNAMIC_FTRACE_WITH_ARGS
266
267config GCC_SUPPORTS_DYNAMIC_FTRACE_WITH_ARGS
268	def_bool CC_IS_GCC
269	depends on $(cc-option,-fpatchable-function-entry=2)
270	select HAVE_DYNAMIC_FTRACE_WITH_ARGS
271
272config 64BIT
273	def_bool y
274
275config MMU
276	def_bool y
277
278config ARM64_PAGE_SHIFT
279	int
280	default 16 if ARM64_64K_PAGES
281	default 14 if ARM64_16K_PAGES
282	default 12
283
284config ARM64_CONT_PTE_SHIFT
285	int
286	default 5 if ARM64_64K_PAGES
287	default 7 if ARM64_16K_PAGES
288	default 4
289
290config ARM64_CONT_PMD_SHIFT
291	int
292	default 5 if ARM64_64K_PAGES
293	default 5 if ARM64_16K_PAGES
294	default 4
295
296config ARCH_MMAP_RND_BITS_MIN
297	default 14 if ARM64_64K_PAGES
298	default 16 if ARM64_16K_PAGES
299	default 18
300
301# max bits determined by the following formula:
302#  VA_BITS - PAGE_SHIFT - 3
303config ARCH_MMAP_RND_BITS_MAX
304	default 19 if ARM64_VA_BITS=36
305	default 24 if ARM64_VA_BITS=39
306	default 27 if ARM64_VA_BITS=42
307	default 30 if ARM64_VA_BITS=47
308	default 29 if ARM64_VA_BITS=48 && ARM64_64K_PAGES
309	default 31 if ARM64_VA_BITS=48 && ARM64_16K_PAGES
310	default 33 if ARM64_VA_BITS=48
311	default 14 if ARM64_64K_PAGES
312	default 16 if ARM64_16K_PAGES
313	default 18
314
315config ARCH_MMAP_RND_COMPAT_BITS_MIN
316	default 7 if ARM64_64K_PAGES
317	default 9 if ARM64_16K_PAGES
318	default 11
319
320config ARCH_MMAP_RND_COMPAT_BITS_MAX
321	default 16
322
323config NO_IOPORT_MAP
324	def_bool y if !PCI
325
326config STACKTRACE_SUPPORT
327	def_bool y
328
329config ILLEGAL_POINTER_VALUE
330	hex
331	default 0xdead000000000000
332
333config LOCKDEP_SUPPORT
334	def_bool y
335
336config GENERIC_BUG
337	def_bool y
338	depends on BUG
339
340config GENERIC_BUG_RELATIVE_POINTERS
341	def_bool y
342	depends on GENERIC_BUG
343
344config GENERIC_HWEIGHT
345	def_bool y
346
347config GENERIC_CSUM
348	def_bool y
349
350config GENERIC_CALIBRATE_DELAY
351	def_bool y
352
353config SMP
354	def_bool y
355
356config KERNEL_MODE_NEON
357	def_bool y
358
359config FIX_EARLYCON_MEM
360	def_bool y
361
362config PGTABLE_LEVELS
363	int
364	default 2 if ARM64_16K_PAGES && ARM64_VA_BITS_36
365	default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42
366	default 3 if ARM64_64K_PAGES && (ARM64_VA_BITS_48 || ARM64_VA_BITS_52)
367	default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39
368	default 3 if ARM64_16K_PAGES && ARM64_VA_BITS_47
369	default 4 if !ARM64_64K_PAGES && ARM64_VA_BITS_48
370
371config ARCH_SUPPORTS_UPROBES
372	def_bool y
373
374config ARCH_PROC_KCORE_TEXT
375	def_bool y
376
377config BROKEN_GAS_INST
378	def_bool !$(as-instr,1:\n.inst 0\n.rept . - 1b\n\nnop\n.endr\n)
379
380config BUILTIN_RETURN_ADDRESS_STRIPS_PAC
381	bool
382	# Clang's __builtin_return_adddress() strips the PAC since 12.0.0
383	# https://reviews.llvm.org/D75044
384	default y if CC_IS_CLANG && (CLANG_VERSION >= 120000)
385	# GCC's __builtin_return_address() strips the PAC since 11.1.0,
386	# and this was backported to 10.2.0, 9.4.0, 8.5.0, but not earlier
387	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94891
388	default y if CC_IS_GCC && (GCC_VERSION >= 110100)
389	default y if CC_IS_GCC && (GCC_VERSION >= 100200) && (GCC_VERSION < 110000)
390	default y if CC_IS_GCC && (GCC_VERSION >=  90400) && (GCC_VERSION < 100000)
391	default y if CC_IS_GCC && (GCC_VERSION >=  80500) && (GCC_VERSION <  90000)
392	default n
393
394config KASAN_SHADOW_OFFSET
395	hex
396	depends on KASAN_GENERIC || KASAN_SW_TAGS
397	default 0xdfff800000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && !KASAN_SW_TAGS
398	default 0xdfffc00000000000 if ARM64_VA_BITS_47 && !KASAN_SW_TAGS
399	default 0xdffffe0000000000 if ARM64_VA_BITS_42 && !KASAN_SW_TAGS
400	default 0xdfffffc000000000 if ARM64_VA_BITS_39 && !KASAN_SW_TAGS
401	default 0xdffffff800000000 if ARM64_VA_BITS_36 && !KASAN_SW_TAGS
402	default 0xefff800000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && KASAN_SW_TAGS
403	default 0xefffc00000000000 if ARM64_VA_BITS_47 && KASAN_SW_TAGS
404	default 0xeffffe0000000000 if ARM64_VA_BITS_42 && KASAN_SW_TAGS
405	default 0xefffffc000000000 if ARM64_VA_BITS_39 && KASAN_SW_TAGS
406	default 0xeffffff800000000 if ARM64_VA_BITS_36 && KASAN_SW_TAGS
407	default 0xffffffffffffffff
408
409config UNWIND_TABLES
410	bool
411
412source "arch/arm64/Kconfig.platforms"
413
414menu "Kernel Features"
415
416menu "ARM errata workarounds via the alternatives framework"
417
418config AMPERE_ERRATUM_AC03_CPU_38
419        bool "AmpereOne: AC03_CPU_38: Certain bits in the Virtualization Translation Control Register and Translation Control Registers do not follow RES0 semantics"
420	default y
421	help
422	  This option adds an alternative code sequence to work around Ampere
423	  erratum AC03_CPU_38 on AmpereOne.
424
425	  The affected design reports FEAT_HAFDBS as not implemented in
426	  ID_AA64MMFR1_EL1.HAFDBS, but (V)TCR_ELx.{HA,HD} are not RES0
427	  as required by the architecture. The unadvertised HAFDBS
428	  implementation suffers from an additional erratum where hardware
429	  A/D updates can occur after a PTE has been marked invalid.
430
431	  The workaround forces KVM to explicitly set VTCR_EL2.HA to 0,
432	  which avoids enabling unadvertised hardware Access Flag management
433	  at stage-2.
434
435	  If unsure, say Y.
436
437config ARM64_WORKAROUND_CLEAN_CACHE
438	bool
439
440config ARM64_ERRATUM_826319
441	bool "Cortex-A53: 826319: System might deadlock if a write cannot complete until read data is accepted"
442	default y
443	select ARM64_WORKAROUND_CLEAN_CACHE
444	help
445	  This option adds an alternative code sequence to work around ARM
446	  erratum 826319 on Cortex-A53 parts up to r0p2 with an AMBA 4 ACE or
447	  AXI master interface and an L2 cache.
448
449	  If a Cortex-A53 uses an AMBA AXI4 ACE interface to other processors
450	  and is unable to accept a certain write via this interface, it will
451	  not progress on read data presented on the read data channel and the
452	  system can deadlock.
453
454	  The workaround promotes data cache clean instructions to
455	  data cache clean-and-invalidate.
456	  Please note that this does not necessarily enable the workaround,
457	  as it depends on the alternative framework, which will only patch
458	  the kernel if an affected CPU is detected.
459
460	  If unsure, say Y.
461
462config ARM64_ERRATUM_827319
463	bool "Cortex-A53: 827319: Data cache clean instructions might cause overlapping transactions to the interconnect"
464	default y
465	select ARM64_WORKAROUND_CLEAN_CACHE
466	help
467	  This option adds an alternative code sequence to work around ARM
468	  erratum 827319 on Cortex-A53 parts up to r0p2 with an AMBA 5 CHI
469	  master interface and an L2 cache.
470
471	  Under certain conditions this erratum can cause a clean line eviction
472	  to occur at the same time as another transaction to the same address
473	  on the AMBA 5 CHI interface, which can cause data corruption if the
474	  interconnect reorders the two transactions.
475
476	  The workaround promotes data cache clean instructions to
477	  data cache clean-and-invalidate.
478	  Please note that this does not necessarily enable the workaround,
479	  as it depends on the alternative framework, which will only patch
480	  the kernel if an affected CPU is detected.
481
482	  If unsure, say Y.
483
484config ARM64_ERRATUM_824069
485	bool "Cortex-A53: 824069: Cache line might not be marked as clean after a CleanShared snoop"
486	default y
487	select ARM64_WORKAROUND_CLEAN_CACHE
488	help
489	  This option adds an alternative code sequence to work around ARM
490	  erratum 824069 on Cortex-A53 parts up to r0p2 when it is connected
491	  to a coherent interconnect.
492
493	  If a Cortex-A53 processor is executing a store or prefetch for
494	  write instruction at the same time as a processor in another
495	  cluster is executing a cache maintenance operation to the same
496	  address, then this erratum might cause a clean cache line to be
497	  incorrectly marked as dirty.
498
499	  The workaround promotes data cache clean instructions to
500	  data cache clean-and-invalidate.
501	  Please note that this option does not necessarily enable the
502	  workaround, as it depends on the alternative framework, which will
503	  only patch the kernel if an affected CPU is detected.
504
505	  If unsure, say Y.
506
507config ARM64_ERRATUM_819472
508	bool "Cortex-A53: 819472: Store exclusive instructions might cause data corruption"
509	default y
510	select ARM64_WORKAROUND_CLEAN_CACHE
511	help
512	  This option adds an alternative code sequence to work around ARM
513	  erratum 819472 on Cortex-A53 parts up to r0p1 with an L2 cache
514	  present when it is connected to a coherent interconnect.
515
516	  If the processor is executing a load and store exclusive sequence at
517	  the same time as a processor in another cluster is executing a cache
518	  maintenance operation to the same address, then this erratum might
519	  cause data corruption.
520
521	  The workaround promotes data cache clean instructions to
522	  data cache clean-and-invalidate.
523	  Please note that this does not necessarily enable the workaround,
524	  as it depends on the alternative framework, which will only patch
525	  the kernel if an affected CPU is detected.
526
527	  If unsure, say Y.
528
529config ARM64_ERRATUM_832075
530	bool "Cortex-A57: 832075: possible deadlock on mixing exclusive memory accesses with device loads"
531	default y
532	help
533	  This option adds an alternative code sequence to work around ARM
534	  erratum 832075 on Cortex-A57 parts up to r1p2.
535
536	  Affected Cortex-A57 parts might deadlock when exclusive load/store
537	  instructions to Write-Back memory are mixed with Device loads.
538
539	  The workaround is to promote device loads to use Load-Acquire
540	  semantics.
541	  Please note that this does not necessarily enable the workaround,
542	  as it depends on the alternative framework, which will only patch
543	  the kernel if an affected CPU is detected.
544
545	  If unsure, say Y.
546
547config ARM64_ERRATUM_834220
548	bool "Cortex-A57: 834220: Stage 2 translation fault might be incorrectly reported in presence of a Stage 1 fault"
549	depends on KVM
550	default y
551	help
552	  This option adds an alternative code sequence to work around ARM
553	  erratum 834220 on Cortex-A57 parts up to r1p2.
554
555	  Affected Cortex-A57 parts might report a Stage 2 translation
556	  fault as the result of a Stage 1 fault for load crossing a
557	  page boundary when there is a permission or device memory
558	  alignment fault at Stage 1 and a translation fault at Stage 2.
559
560	  The workaround is to verify that the Stage 1 translation
561	  doesn't generate a fault before handling the Stage 2 fault.
562	  Please note that this does not necessarily enable the workaround,
563	  as it depends on the alternative framework, which will only patch
564	  the kernel if an affected CPU is detected.
565
566	  If unsure, say Y.
567
568config ARM64_ERRATUM_1742098
569	bool "Cortex-A57/A72: 1742098: ELR recorded incorrectly on interrupt taken between cryptographic instructions in a sequence"
570	depends on COMPAT
571	default y
572	help
573	  This option removes the AES hwcap for aarch32 user-space to
574	  workaround erratum 1742098 on Cortex-A57 and Cortex-A72.
575
576	  Affected parts may corrupt the AES state if an interrupt is
577	  taken between a pair of AES instructions. These instructions
578	  are only present if the cryptography extensions are present.
579	  All software should have a fallback implementation for CPUs
580	  that don't implement the cryptography extensions.
581
582	  If unsure, say Y.
583
584config ARM64_ERRATUM_845719
585	bool "Cortex-A53: 845719: a load might read incorrect data"
586	depends on COMPAT
587	default y
588	help
589	  This option adds an alternative code sequence to work around ARM
590	  erratum 845719 on Cortex-A53 parts up to r0p4.
591
592	  When running a compat (AArch32) userspace on an affected Cortex-A53
593	  part, a load at EL0 from a virtual address that matches the bottom 32
594	  bits of the virtual address used by a recent load at (AArch64) EL1
595	  might return incorrect data.
596
597	  The workaround is to write the contextidr_el1 register on exception
598	  return to a 32-bit task.
599	  Please note that this does not necessarily enable the workaround,
600	  as it depends on the alternative framework, which will only patch
601	  the kernel if an affected CPU is detected.
602
603	  If unsure, say Y.
604
605config ARM64_ERRATUM_843419
606	bool "Cortex-A53: 843419: A load or store might access an incorrect address"
607	default y
608	help
609	  This option links the kernel with '--fix-cortex-a53-843419' and
610	  enables PLT support to replace certain ADRP instructions, which can
611	  cause subsequent memory accesses to use an incorrect address on
612	  Cortex-A53 parts up to r0p4.
613
614	  If unsure, say Y.
615
616config ARM64_LD_HAS_FIX_ERRATUM_843419
617	def_bool $(ld-option,--fix-cortex-a53-843419)
618
619config ARM64_ERRATUM_1024718
620	bool "Cortex-A55: 1024718: Update of DBM/AP bits without break before make might result in incorrect update"
621	default y
622	help
623	  This option adds a workaround for ARM Cortex-A55 Erratum 1024718.
624
625	  Affected Cortex-A55 cores (all revisions) could cause incorrect
626	  update of the hardware dirty bit when the DBM/AP bits are updated
627	  without a break-before-make. The workaround is to disable the usage
628	  of hardware DBM locally on the affected cores. CPUs not affected by
629	  this erratum will continue to use the feature.
630
631	  If unsure, say Y.
632
633config ARM64_ERRATUM_1418040
634	bool "Cortex-A76/Neoverse-N1: MRC read following MRRC read of specific Generic Timer in AArch32 might give incorrect result"
635	default y
636	depends on COMPAT
637	help
638	  This option adds a workaround for ARM Cortex-A76/Neoverse-N1
639	  errata 1188873 and 1418040.
640
641	  Affected Cortex-A76/Neoverse-N1 cores (r0p0 to r3p1) could
642	  cause register corruption when accessing the timer registers
643	  from AArch32 userspace.
644
645	  If unsure, say Y.
646
647config ARM64_WORKAROUND_SPECULATIVE_AT
648	bool
649
650config ARM64_ERRATUM_1165522
651	bool "Cortex-A76: 1165522: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
652	default y
653	select ARM64_WORKAROUND_SPECULATIVE_AT
654	help
655	  This option adds a workaround for ARM Cortex-A76 erratum 1165522.
656
657	  Affected Cortex-A76 cores (r0p0, r1p0, r2p0) could end-up with
658	  corrupted TLBs by speculating an AT instruction during a guest
659	  context switch.
660
661	  If unsure, say Y.
662
663config ARM64_ERRATUM_1319367
664	bool "Cortex-A57/A72: 1319537: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
665	default y
666	select ARM64_WORKAROUND_SPECULATIVE_AT
667	help
668	  This option adds work arounds for ARM Cortex-A57 erratum 1319537
669	  and A72 erratum 1319367
670
671	  Cortex-A57 and A72 cores could end-up with corrupted TLBs by
672	  speculating an AT instruction during a guest context switch.
673
674	  If unsure, say Y.
675
676config ARM64_ERRATUM_1530923
677	bool "Cortex-A55: 1530923: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
678	default y
679	select ARM64_WORKAROUND_SPECULATIVE_AT
680	help
681	  This option adds a workaround for ARM Cortex-A55 erratum 1530923.
682
683	  Affected Cortex-A55 cores (r0p0, r0p1, r1p0, r2p0) could end-up with
684	  corrupted TLBs by speculating an AT instruction during a guest
685	  context switch.
686
687	  If unsure, say Y.
688
689config ARM64_WORKAROUND_REPEAT_TLBI
690	bool
691
692config ARM64_ERRATUM_2441007
693	bool "Cortex-A55: Completion of affected memory accesses might not be guaranteed by completion of a TLBI"
694	default y
695	select ARM64_WORKAROUND_REPEAT_TLBI
696	help
697	  This option adds a workaround for ARM Cortex-A55 erratum #2441007.
698
699	  Under very rare circumstances, affected Cortex-A55 CPUs
700	  may not handle a race between a break-before-make sequence on one
701	  CPU, and another CPU accessing the same page. This could allow a
702	  store to a page that has been unmapped.
703
704	  Work around this by adding the affected CPUs to the list that needs
705	  TLB sequences to be done twice.
706
707	  If unsure, say Y.
708
709config ARM64_ERRATUM_1286807
710	bool "Cortex-A76: Modification of the translation table for a virtual address might lead to read-after-read ordering violation"
711	default y
712	select ARM64_WORKAROUND_REPEAT_TLBI
713	help
714	  This option adds a workaround for ARM Cortex-A76 erratum 1286807.
715
716	  On the affected Cortex-A76 cores (r0p0 to r3p0), if a virtual
717	  address for a cacheable mapping of a location is being
718	  accessed by a core while another core is remapping the virtual
719	  address to a new physical page using the recommended
720	  break-before-make sequence, then under very rare circumstances
721	  TLBI+DSB completes before a read using the translation being
722	  invalidated has been observed by other observers. The
723	  workaround repeats the TLBI+DSB operation.
724
725config ARM64_ERRATUM_1463225
726	bool "Cortex-A76: Software Step might prevent interrupt recognition"
727	default y
728	help
729	  This option adds a workaround for Arm Cortex-A76 erratum 1463225.
730
731	  On the affected Cortex-A76 cores (r0p0 to r3p1), software stepping
732	  of a system call instruction (SVC) can prevent recognition of
733	  subsequent interrupts when software stepping is disabled in the
734	  exception handler of the system call and either kernel debugging
735	  is enabled or VHE is in use.
736
737	  Work around the erratum by triggering a dummy step exception
738	  when handling a system call from a task that is being stepped
739	  in a VHE configuration of the kernel.
740
741	  If unsure, say Y.
742
743config ARM64_ERRATUM_1542419
744	bool "Neoverse-N1: workaround mis-ordering of instruction fetches"
745	default y
746	help
747	  This option adds a workaround for ARM Neoverse-N1 erratum
748	  1542419.
749
750	  Affected Neoverse-N1 cores could execute a stale instruction when
751	  modified by another CPU. The workaround depends on a firmware
752	  counterpart.
753
754	  Workaround the issue by hiding the DIC feature from EL0. This
755	  forces user-space to perform cache maintenance.
756
757	  If unsure, say Y.
758
759config ARM64_ERRATUM_1508412
760	bool "Cortex-A77: 1508412: workaround deadlock on sequence of NC/Device load and store exclusive or PAR read"
761	default y
762	help
763	  This option adds a workaround for Arm Cortex-A77 erratum 1508412.
764
765	  Affected Cortex-A77 cores (r0p0, r1p0) could deadlock on a sequence
766	  of a store-exclusive or read of PAR_EL1 and a load with device or
767	  non-cacheable memory attributes. The workaround depends on a firmware
768	  counterpart.
769
770	  KVM guests must also have the workaround implemented or they can
771	  deadlock the system.
772
773	  Work around the issue by inserting DMB SY barriers around PAR_EL1
774	  register reads and warning KVM users. The DMB barrier is sufficient
775	  to prevent a speculative PAR_EL1 read.
776
777	  If unsure, say Y.
778
779config ARM64_WORKAROUND_TRBE_OVERWRITE_FILL_MODE
780	bool
781
782config ARM64_ERRATUM_2051678
783	bool "Cortex-A510: 2051678: disable Hardware Update of the page table dirty bit"
784	default y
785	help
786	  This options adds the workaround for ARM Cortex-A510 erratum ARM64_ERRATUM_2051678.
787	  Affected Cortex-A510 might not respect the ordering rules for
788	  hardware update of the page table's dirty bit. The workaround
789	  is to not enable the feature on affected CPUs.
790
791	  If unsure, say Y.
792
793config ARM64_ERRATUM_2077057
794	bool "Cortex-A510: 2077057: workaround software-step corrupting SPSR_EL2"
795	default y
796	help
797	  This option adds the workaround for ARM Cortex-A510 erratum 2077057.
798	  Affected Cortex-A510 may corrupt SPSR_EL2 when the a step exception is
799	  expected, but a Pointer Authentication trap is taken instead. The
800	  erratum causes SPSR_EL1 to be copied to SPSR_EL2, which could allow
801	  EL1 to cause a return to EL2 with a guest controlled ELR_EL2.
802
803	  This can only happen when EL2 is stepping EL1.
804
805	  When these conditions occur, the SPSR_EL2 value is unchanged from the
806	  previous guest entry, and can be restored from the in-memory copy.
807
808	  If unsure, say Y.
809
810config ARM64_ERRATUM_2658417
811	bool "Cortex-A510: 2658417: remove BF16 support due to incorrect result"
812	default y
813	help
814	  This option adds the workaround for ARM Cortex-A510 erratum 2658417.
815	  Affected Cortex-A510 (r0p0 to r1p1) may produce the wrong result for
816	  BFMMLA or VMMLA instructions in rare circumstances when a pair of
817	  A510 CPUs are using shared neon hardware. As the sharing is not
818	  discoverable by the kernel, hide the BF16 HWCAP to indicate that
819	  user-space should not be using these instructions.
820
821	  If unsure, say Y.
822
823config ARM64_ERRATUM_2119858
824	bool "Cortex-A710/X2: 2119858: workaround TRBE overwriting trace data in FILL mode"
825	default y
826	depends on CORESIGHT_TRBE
827	select ARM64_WORKAROUND_TRBE_OVERWRITE_FILL_MODE
828	help
829	  This option adds the workaround for ARM Cortex-A710/X2 erratum 2119858.
830
831	  Affected Cortex-A710/X2 cores could overwrite up to 3 cache lines of trace
832	  data at the base of the buffer (pointed to by TRBASER_EL1) in FILL mode in
833	  the event of a WRAP event.
834
835	  Work around the issue by always making sure we move the TRBPTR_EL1 by
836	  256 bytes before enabling the buffer and filling the first 256 bytes of
837	  the buffer with ETM ignore packets upon disabling.
838
839	  If unsure, say Y.
840
841config ARM64_ERRATUM_2139208
842	bool "Neoverse-N2: 2139208: workaround TRBE overwriting trace data in FILL mode"
843	default y
844	depends on CORESIGHT_TRBE
845	select ARM64_WORKAROUND_TRBE_OVERWRITE_FILL_MODE
846	help
847	  This option adds the workaround for ARM Neoverse-N2 erratum 2139208.
848
849	  Affected Neoverse-N2 cores could overwrite up to 3 cache lines of trace
850	  data at the base of the buffer (pointed to by TRBASER_EL1) in FILL mode in
851	  the event of a WRAP event.
852
853	  Work around the issue by always making sure we move the TRBPTR_EL1 by
854	  256 bytes before enabling the buffer and filling the first 256 bytes of
855	  the buffer with ETM ignore packets upon disabling.
856
857	  If unsure, say Y.
858
859config ARM64_WORKAROUND_TSB_FLUSH_FAILURE
860	bool
861
862config ARM64_ERRATUM_2054223
863	bool "Cortex-A710: 2054223: workaround TSB instruction failing to flush trace"
864	default y
865	select ARM64_WORKAROUND_TSB_FLUSH_FAILURE
866	help
867	  Enable workaround for ARM Cortex-A710 erratum 2054223
868
869	  Affected cores may fail to flush the trace data on a TSB instruction, when
870	  the PE is in trace prohibited state. This will cause losing a few bytes
871	  of the trace cached.
872
873	  Workaround is to issue two TSB consecutively on affected cores.
874
875	  If unsure, say Y.
876
877config ARM64_ERRATUM_2067961
878	bool "Neoverse-N2: 2067961: workaround TSB instruction failing to flush trace"
879	default y
880	select ARM64_WORKAROUND_TSB_FLUSH_FAILURE
881	help
882	  Enable workaround for ARM Neoverse-N2 erratum 2067961
883
884	  Affected cores may fail to flush the trace data on a TSB instruction, when
885	  the PE is in trace prohibited state. This will cause losing a few bytes
886	  of the trace cached.
887
888	  Workaround is to issue two TSB consecutively on affected cores.
889
890	  If unsure, say Y.
891
892config ARM64_WORKAROUND_TRBE_WRITE_OUT_OF_RANGE
893	bool
894
895config ARM64_ERRATUM_2253138
896	bool "Neoverse-N2: 2253138: workaround TRBE writing to address out-of-range"
897	depends on CORESIGHT_TRBE
898	default y
899	select ARM64_WORKAROUND_TRBE_WRITE_OUT_OF_RANGE
900	help
901	  This option adds the workaround for ARM Neoverse-N2 erratum 2253138.
902
903	  Affected Neoverse-N2 cores might write to an out-of-range address, not reserved
904	  for TRBE. Under some conditions, the TRBE might generate a write to the next
905	  virtually addressed page following the last page of the TRBE address space
906	  (i.e., the TRBLIMITR_EL1.LIMIT), instead of wrapping around to the base.
907
908	  Work around this in the driver by always making sure that there is a
909	  page beyond the TRBLIMITR_EL1.LIMIT, within the space allowed for the TRBE.
910
911	  If unsure, say Y.
912
913config ARM64_ERRATUM_2224489
914	bool "Cortex-A710/X2: 2224489: workaround TRBE writing to address out-of-range"
915	depends on CORESIGHT_TRBE
916	default y
917	select ARM64_WORKAROUND_TRBE_WRITE_OUT_OF_RANGE
918	help
919	  This option adds the workaround for ARM Cortex-A710/X2 erratum 2224489.
920
921	  Affected Cortex-A710/X2 cores might write to an out-of-range address, not reserved
922	  for TRBE. Under some conditions, the TRBE might generate a write to the next
923	  virtually addressed page following the last page of the TRBE address space
924	  (i.e., the TRBLIMITR_EL1.LIMIT), instead of wrapping around to the base.
925
926	  Work around this in the driver by always making sure that there is a
927	  page beyond the TRBLIMITR_EL1.LIMIT, within the space allowed for the TRBE.
928
929	  If unsure, say Y.
930
931config ARM64_ERRATUM_2441009
932	bool "Cortex-A510: Completion of affected memory accesses might not be guaranteed by completion of a TLBI"
933	default y
934	select ARM64_WORKAROUND_REPEAT_TLBI
935	help
936	  This option adds a workaround for ARM Cortex-A510 erratum #2441009.
937
938	  Under very rare circumstances, affected Cortex-A510 CPUs
939	  may not handle a race between a break-before-make sequence on one
940	  CPU, and another CPU accessing the same page. This could allow a
941	  store to a page that has been unmapped.
942
943	  Work around this by adding the affected CPUs to the list that needs
944	  TLB sequences to be done twice.
945
946	  If unsure, say Y.
947
948config ARM64_ERRATUM_2064142
949	bool "Cortex-A510: 2064142: workaround TRBE register writes while disabled"
950	depends on CORESIGHT_TRBE
951	default y
952	help
953	  This option adds the workaround for ARM Cortex-A510 erratum 2064142.
954
955	  Affected Cortex-A510 core might fail to write into system registers after the
956	  TRBE has been disabled. Under some conditions after the TRBE has been disabled
957	  writes into TRBE registers TRBLIMITR_EL1, TRBPTR_EL1, TRBBASER_EL1, TRBSR_EL1,
958	  and TRBTRG_EL1 will be ignored and will not be effected.
959
960	  Work around this in the driver by executing TSB CSYNC and DSB after collection
961	  is stopped and before performing a system register write to one of the affected
962	  registers.
963
964	  If unsure, say Y.
965
966config ARM64_ERRATUM_2038923
967	bool "Cortex-A510: 2038923: workaround TRBE corruption with enable"
968	depends on CORESIGHT_TRBE
969	default y
970	help
971	  This option adds the workaround for ARM Cortex-A510 erratum 2038923.
972
973	  Affected Cortex-A510 core might cause an inconsistent view on whether trace is
974	  prohibited within the CPU. As a result, the trace buffer or trace buffer state
975	  might be corrupted. This happens after TRBE buffer has been enabled by setting
976	  TRBLIMITR_EL1.E, followed by just a single context synchronization event before
977	  execution changes from a context, in which trace is prohibited to one where it
978	  isn't, or vice versa. In these mentioned conditions, the view of whether trace
979	  is prohibited is inconsistent between parts of the CPU, and the trace buffer or
980	  the trace buffer state might be corrupted.
981
982	  Work around this in the driver by preventing an inconsistent view of whether the
983	  trace is prohibited or not based on TRBLIMITR_EL1.E by immediately following a
984	  change to TRBLIMITR_EL1.E with at least one ISB instruction before an ERET, or
985	  two ISB instructions if no ERET is to take place.
986
987	  If unsure, say Y.
988
989config ARM64_ERRATUM_1902691
990	bool "Cortex-A510: 1902691: workaround TRBE trace corruption"
991	depends on CORESIGHT_TRBE
992	default y
993	help
994	  This option adds the workaround for ARM Cortex-A510 erratum 1902691.
995
996	  Affected Cortex-A510 core might cause trace data corruption, when being written
997	  into the memory. Effectively TRBE is broken and hence cannot be used to capture
998	  trace data.
999
1000	  Work around this problem in the driver by just preventing TRBE initialization on
1001	  affected cpus. The firmware must have disabled the access to TRBE for the kernel
1002	  on such implementations. This will cover the kernel for any firmware that doesn't
1003	  do this already.
1004
1005	  If unsure, say Y.
1006
1007config ARM64_ERRATUM_2457168
1008	bool "Cortex-A510: 2457168: workaround for AMEVCNTR01 incrementing incorrectly"
1009	depends on ARM64_AMU_EXTN
1010	default y
1011	help
1012	  This option adds the workaround for ARM Cortex-A510 erratum 2457168.
1013
1014	  The AMU counter AMEVCNTR01 (constant counter) should increment at the same rate
1015	  as the system counter. On affected Cortex-A510 cores AMEVCNTR01 increments
1016	  incorrectly giving a significantly higher output value.
1017
1018	  Work around this problem by returning 0 when reading the affected counter in
1019	  key locations that results in disabling all users of this counter. This effect
1020	  is the same to firmware disabling affected counters.
1021
1022	  If unsure, say Y.
1023
1024config ARM64_ERRATUM_2645198
1025	bool "Cortex-A715: 2645198: Workaround possible [ESR|FAR]_ELx corruption"
1026	default y
1027	help
1028	  This option adds the workaround for ARM Cortex-A715 erratum 2645198.
1029
1030	  If a Cortex-A715 cpu sees a page mapping permissions change from executable
1031	  to non-executable, it may corrupt the ESR_ELx and FAR_ELx registers on the
1032	  next instruction abort caused by permission fault.
1033
1034	  Only user-space does executable to non-executable permission transition via
1035	  mprotect() system call. Workaround the problem by doing a break-before-make
1036	  TLB invalidation, for all changes to executable user space mappings.
1037
1038	  If unsure, say Y.
1039
1040config ARM64_ERRATUM_2966298
1041	bool "Cortex-A520: 2966298: workaround for speculatively executed unprivileged load"
1042	default y
1043	help
1044	  This option adds the workaround for ARM Cortex-A520 erratum 2966298.
1045
1046	  On an affected Cortex-A520 core, a speculatively executed unprivileged
1047	  load might leak data from a privileged level via a cache side channel.
1048
1049	  Work around this problem by executing a TLBI before returning to EL0.
1050
1051	  If unsure, say Y.
1052
1053config CAVIUM_ERRATUM_22375
1054	bool "Cavium erratum 22375, 24313"
1055	default y
1056	help
1057	  Enable workaround for errata 22375 and 24313.
1058
1059	  This implements two gicv3-its errata workarounds for ThunderX. Both
1060	  with a small impact affecting only ITS table allocation.
1061
1062	    erratum 22375: only alloc 8MB table size
1063	    erratum 24313: ignore memory access type
1064
1065	  The fixes are in ITS initialization and basically ignore memory access
1066	  type and table size provided by the TYPER and BASER registers.
1067
1068	  If unsure, say Y.
1069
1070config CAVIUM_ERRATUM_23144
1071	bool "Cavium erratum 23144: ITS SYNC hang on dual socket system"
1072	depends on NUMA
1073	default y
1074	help
1075	  ITS SYNC command hang for cross node io and collections/cpu mapping.
1076
1077	  If unsure, say Y.
1078
1079config CAVIUM_ERRATUM_23154
1080	bool "Cavium errata 23154 and 38545: GICv3 lacks HW synchronisation"
1081	default y
1082	help
1083	  The ThunderX GICv3 implementation requires a modified version for
1084	  reading the IAR status to ensure data synchronization
1085	  (access to icc_iar1_el1 is not sync'ed before and after).
1086
1087	  It also suffers from erratum 38545 (also present on Marvell's
1088	  OcteonTX and OcteonTX2), resulting in deactivated interrupts being
1089	  spuriously presented to the CPU interface.
1090
1091	  If unsure, say Y.
1092
1093config CAVIUM_ERRATUM_27456
1094	bool "Cavium erratum 27456: Broadcast TLBI instructions may cause icache corruption"
1095	default y
1096	help
1097	  On ThunderX T88 pass 1.x through 2.1 parts, broadcast TLBI
1098	  instructions may cause the icache to become corrupted if it
1099	  contains data for a non-current ASID.  The fix is to
1100	  invalidate the icache when changing the mm context.
1101
1102	  If unsure, say Y.
1103
1104config CAVIUM_ERRATUM_30115
1105	bool "Cavium erratum 30115: Guest may disable interrupts in host"
1106	default y
1107	help
1108	  On ThunderX T88 pass 1.x through 2.2, T81 pass 1.0 through
1109	  1.2, and T83 Pass 1.0, KVM guest execution may disable
1110	  interrupts in host. Trapping both GICv3 group-0 and group-1
1111	  accesses sidesteps the issue.
1112
1113	  If unsure, say Y.
1114
1115config CAVIUM_TX2_ERRATUM_219
1116	bool "Cavium ThunderX2 erratum 219: PRFM between TTBR change and ISB fails"
1117	default y
1118	help
1119	  On Cavium ThunderX2, a load, store or prefetch instruction between a
1120	  TTBR update and the corresponding context synchronizing operation can
1121	  cause a spurious Data Abort to be delivered to any hardware thread in
1122	  the CPU core.
1123
1124	  Work around the issue by avoiding the problematic code sequence and
1125	  trapping KVM guest TTBRx_EL1 writes to EL2 when SMT is enabled. The
1126	  trap handler performs the corresponding register access, skips the
1127	  instruction and ensures context synchronization by virtue of the
1128	  exception return.
1129
1130	  If unsure, say Y.
1131
1132config FUJITSU_ERRATUM_010001
1133	bool "Fujitsu-A64FX erratum E#010001: Undefined fault may occur wrongly"
1134	default y
1135	help
1136	  This option adds a workaround for Fujitsu-A64FX erratum E#010001.
1137	  On some variants of the Fujitsu-A64FX cores ver(1.0, 1.1), memory
1138	  accesses may cause undefined fault (Data abort, DFSC=0b111111).
1139	  This fault occurs under a specific hardware condition when a
1140	  load/store instruction performs an address translation using:
1141	  case-1  TTBR0_EL1 with TCR_EL1.NFD0 == 1.
1142	  case-2  TTBR0_EL2 with TCR_EL2.NFD0 == 1.
1143	  case-3  TTBR1_EL1 with TCR_EL1.NFD1 == 1.
1144	  case-4  TTBR1_EL2 with TCR_EL2.NFD1 == 1.
1145
1146	  The workaround is to ensure these bits are clear in TCR_ELx.
1147	  The workaround only affects the Fujitsu-A64FX.
1148
1149	  If unsure, say Y.
1150
1151config HISILICON_ERRATUM_161600802
1152	bool "Hip07 161600802: Erroneous redistributor VLPI base"
1153	default y
1154	help
1155	  The HiSilicon Hip07 SoC uses the wrong redistributor base
1156	  when issued ITS commands such as VMOVP and VMAPP, and requires
1157	  a 128kB offset to be applied to the target address in this commands.
1158
1159	  If unsure, say Y.
1160
1161config QCOM_FALKOR_ERRATUM_1003
1162	bool "Falkor E1003: Incorrect translation due to ASID change"
1163	default y
1164	help
1165	  On Falkor v1, an incorrect ASID may be cached in the TLB when ASID
1166	  and BADDR are changed together in TTBRx_EL1. Since we keep the ASID
1167	  in TTBR1_EL1, this situation only occurs in the entry trampoline and
1168	  then only for entries in the walk cache, since the leaf translation
1169	  is unchanged. Work around the erratum by invalidating the walk cache
1170	  entries for the trampoline before entering the kernel proper.
1171
1172config QCOM_FALKOR_ERRATUM_1009
1173	bool "Falkor E1009: Prematurely complete a DSB after a TLBI"
1174	default y
1175	select ARM64_WORKAROUND_REPEAT_TLBI
1176	help
1177	  On Falkor v1, the CPU may prematurely complete a DSB following a
1178	  TLBI xxIS invalidate maintenance operation. Repeat the TLBI operation
1179	  one more time to fix the issue.
1180
1181	  If unsure, say Y.
1182
1183config QCOM_QDF2400_ERRATUM_0065
1184	bool "QDF2400 E0065: Incorrect GITS_TYPER.ITT_Entry_size"
1185	default y
1186	help
1187	  On Qualcomm Datacenter Technologies QDF2400 SoC, ITS hardware reports
1188	  ITE size incorrectly. The GITS_TYPER.ITT_Entry_size field should have
1189	  been indicated as 16Bytes (0xf), not 8Bytes (0x7).
1190
1191	  If unsure, say Y.
1192
1193config QCOM_FALKOR_ERRATUM_E1041
1194	bool "Falkor E1041: Speculative instruction fetches might cause errant memory access"
1195	default y
1196	help
1197	  Falkor CPU may speculatively fetch instructions from an improper
1198	  memory location when MMU translation is changed from SCTLR_ELn[M]=1
1199	  to SCTLR_ELn[M]=0. Prefix an ISB instruction to fix the problem.
1200
1201	  If unsure, say Y.
1202
1203config NVIDIA_CARMEL_CNP_ERRATUM
1204	bool "NVIDIA Carmel CNP: CNP on Carmel semantically different than ARM cores"
1205	default y
1206	help
1207	  If CNP is enabled on Carmel cores, non-sharable TLBIs on a core will not
1208	  invalidate shared TLB entries installed by a different core, as it would
1209	  on standard ARM cores.
1210
1211	  If unsure, say Y.
1212
1213config ROCKCHIP_ERRATUM_3588001
1214	bool "Rockchip 3588001: GIC600 can not support shareability attributes"
1215	default y
1216	help
1217	  The Rockchip RK3588 GIC600 SoC integration does not support ACE/ACE-lite.
1218	  This means, that its sharability feature may not be used, even though it
1219	  is supported by the IP itself.
1220
1221	  If unsure, say Y.
1222
1223config SOCIONEXT_SYNQUACER_PREITS
1224	bool "Socionext Synquacer: Workaround for GICv3 pre-ITS"
1225	default y
1226	help
1227	  Socionext Synquacer SoCs implement a separate h/w block to generate
1228	  MSI doorbell writes with non-zero values for the device ID.
1229
1230	  If unsure, say Y.
1231
1232endmenu # "ARM errata workarounds via the alternatives framework"
1233
1234choice
1235	prompt "Page size"
1236	default ARM64_4K_PAGES
1237	help
1238	  Page size (translation granule) configuration.
1239
1240config ARM64_4K_PAGES
1241	bool "4KB"
1242	help
1243	  This feature enables 4KB pages support.
1244
1245config ARM64_16K_PAGES
1246	bool "16KB"
1247	help
1248	  The system will use 16KB pages support. AArch32 emulation
1249	  requires applications compiled with 16K (or a multiple of 16K)
1250	  aligned segments.
1251
1252config ARM64_64K_PAGES
1253	bool "64KB"
1254	help
1255	  This feature enables 64KB pages support (4KB by default)
1256	  allowing only two levels of page tables and faster TLB
1257	  look-up. AArch32 emulation requires applications compiled
1258	  with 64K aligned segments.
1259
1260endchoice
1261
1262choice
1263	prompt "Virtual address space size"
1264	default ARM64_VA_BITS_39 if ARM64_4K_PAGES
1265	default ARM64_VA_BITS_47 if ARM64_16K_PAGES
1266	default ARM64_VA_BITS_42 if ARM64_64K_PAGES
1267	help
1268	  Allows choosing one of multiple possible virtual address
1269	  space sizes. The level of translation table is determined by
1270	  a combination of page size and virtual address space size.
1271
1272config ARM64_VA_BITS_36
1273	bool "36-bit" if EXPERT
1274	depends on ARM64_16K_PAGES
1275
1276config ARM64_VA_BITS_39
1277	bool "39-bit"
1278	depends on ARM64_4K_PAGES
1279
1280config ARM64_VA_BITS_42
1281	bool "42-bit"
1282	depends on ARM64_64K_PAGES
1283
1284config ARM64_VA_BITS_47
1285	bool "47-bit"
1286	depends on ARM64_16K_PAGES
1287
1288config ARM64_VA_BITS_48
1289	bool "48-bit"
1290
1291config ARM64_VA_BITS_52
1292	bool "52-bit"
1293	depends on ARM64_64K_PAGES && (ARM64_PAN || !ARM64_SW_TTBR0_PAN)
1294	help
1295	  Enable 52-bit virtual addressing for userspace when explicitly
1296	  requested via a hint to mmap(). The kernel will also use 52-bit
1297	  virtual addresses for its own mappings (provided HW support for
1298	  this feature is available, otherwise it reverts to 48-bit).
1299
1300	  NOTE: Enabling 52-bit virtual addressing in conjunction with
1301	  ARMv8.3 Pointer Authentication will result in the PAC being
1302	  reduced from 7 bits to 3 bits, which may have a significant
1303	  impact on its susceptibility to brute-force attacks.
1304
1305	  If unsure, select 48-bit virtual addressing instead.
1306
1307endchoice
1308
1309config ARM64_FORCE_52BIT
1310	bool "Force 52-bit virtual addresses for userspace"
1311	depends on ARM64_VA_BITS_52 && EXPERT
1312	help
1313	  For systems with 52-bit userspace VAs enabled, the kernel will attempt
1314	  to maintain compatibility with older software by providing 48-bit VAs
1315	  unless a hint is supplied to mmap.
1316
1317	  This configuration option disables the 48-bit compatibility logic, and
1318	  forces all userspace addresses to be 52-bit on HW that supports it. One
1319	  should only enable this configuration option for stress testing userspace
1320	  memory management code. If unsure say N here.
1321
1322config ARM64_VA_BITS
1323	int
1324	default 36 if ARM64_VA_BITS_36
1325	default 39 if ARM64_VA_BITS_39
1326	default 42 if ARM64_VA_BITS_42
1327	default 47 if ARM64_VA_BITS_47
1328	default 48 if ARM64_VA_BITS_48
1329	default 52 if ARM64_VA_BITS_52
1330
1331choice
1332	prompt "Physical address space size"
1333	default ARM64_PA_BITS_48
1334	help
1335	  Choose the maximum physical address range that the kernel will
1336	  support.
1337
1338config ARM64_PA_BITS_48
1339	bool "48-bit"
1340
1341config ARM64_PA_BITS_52
1342	bool "52-bit (ARMv8.2)"
1343	depends on ARM64_64K_PAGES
1344	depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
1345	help
1346	  Enable support for a 52-bit physical address space, introduced as
1347	  part of the ARMv8.2-LPA extension.
1348
1349	  With this enabled, the kernel will also continue to work on CPUs that
1350	  do not support ARMv8.2-LPA, but with some added memory overhead (and
1351	  minor performance overhead).
1352
1353endchoice
1354
1355config ARM64_PA_BITS
1356	int
1357	default 48 if ARM64_PA_BITS_48
1358	default 52 if ARM64_PA_BITS_52
1359
1360choice
1361	prompt "Endianness"
1362	default CPU_LITTLE_ENDIAN
1363	help
1364	  Select the endianness of data accesses performed by the CPU. Userspace
1365	  applications will need to be compiled and linked for the endianness
1366	  that is selected here.
1367
1368config CPU_BIG_ENDIAN
1369	bool "Build big-endian kernel"
1370	depends on !LD_IS_LLD || LLD_VERSION >= 130000
1371	# https://github.com/llvm/llvm-project/commit/1379b150991f70a5782e9a143c2ba5308da1161c
1372	depends on AS_IS_GNU || AS_VERSION >= 150000
1373	help
1374	  Say Y if you plan on running a kernel with a big-endian userspace.
1375
1376config CPU_LITTLE_ENDIAN
1377	bool "Build little-endian kernel"
1378	help
1379	  Say Y if you plan on running a kernel with a little-endian userspace.
1380	  This is usually the case for distributions targeting arm64.
1381
1382endchoice
1383
1384config SCHED_MC
1385	bool "Multi-core scheduler support"
1386	help
1387	  Multi-core scheduler support improves the CPU scheduler's decision
1388	  making when dealing with multi-core CPU chips at a cost of slightly
1389	  increased overhead in some places. If unsure say N here.
1390
1391config SCHED_CLUSTER
1392	bool "Cluster scheduler support"
1393	help
1394	  Cluster scheduler support improves the CPU scheduler's decision
1395	  making when dealing with machines that have clusters of CPUs.
1396	  Cluster usually means a couple of CPUs which are placed closely
1397	  by sharing mid-level caches, last-level cache tags or internal
1398	  busses.
1399
1400config SCHED_SMT
1401	bool "SMT scheduler support"
1402	help
1403	  Improves the CPU scheduler's decision making when dealing with
1404	  MultiThreading at a cost of slightly increased overhead in some
1405	  places. If unsure say N here.
1406
1407config NR_CPUS
1408	int "Maximum number of CPUs (2-4096)"
1409	range 2 4096
1410	default "256"
1411
1412config HOTPLUG_CPU
1413	bool "Support for hot-pluggable CPUs"
1414	select GENERIC_IRQ_MIGRATION
1415	help
1416	  Say Y here to experiment with turning CPUs off and on.  CPUs
1417	  can be controlled through /sys/devices/system/cpu.
1418
1419# Common NUMA Features
1420config NUMA
1421	bool "NUMA Memory Allocation and Scheduler Support"
1422	select GENERIC_ARCH_NUMA
1423	select ACPI_NUMA if ACPI
1424	select OF_NUMA
1425	select HAVE_SETUP_PER_CPU_AREA
1426	select NEED_PER_CPU_EMBED_FIRST_CHUNK
1427	select NEED_PER_CPU_PAGE_FIRST_CHUNK
1428	select USE_PERCPU_NUMA_NODE_ID
1429	help
1430	  Enable NUMA (Non-Uniform Memory Access) support.
1431
1432	  The kernel will try to allocate memory used by a CPU on the
1433	  local memory of the CPU and add some more
1434	  NUMA awareness to the kernel.
1435
1436config NODES_SHIFT
1437	int "Maximum NUMA Nodes (as a power of 2)"
1438	range 1 10
1439	default "4"
1440	depends on NUMA
1441	help
1442	  Specify the maximum number of NUMA Nodes available on the target
1443	  system.  Increases memory reserved to accommodate various tables.
1444
1445source "kernel/Kconfig.hz"
1446
1447config ARCH_SPARSEMEM_ENABLE
1448	def_bool y
1449	select SPARSEMEM_VMEMMAP_ENABLE
1450	select SPARSEMEM_VMEMMAP
1451
1452config HW_PERF_EVENTS
1453	def_bool y
1454	depends on ARM_PMU
1455
1456# Supported by clang >= 7.0 or GCC >= 12.0.0
1457config CC_HAVE_SHADOW_CALL_STACK
1458	def_bool $(cc-option, -fsanitize=shadow-call-stack -ffixed-x18)
1459
1460config PARAVIRT
1461	bool "Enable paravirtualization code"
1462	help
1463	  This changes the kernel so it can modify itself when it is run
1464	  under a hypervisor, potentially improving performance significantly
1465	  over full virtualization.
1466
1467config PARAVIRT_TIME_ACCOUNTING
1468	bool "Paravirtual steal time accounting"
1469	select PARAVIRT
1470	help
1471	  Select this option to enable fine granularity task steal time
1472	  accounting. Time spent executing other tasks in parallel with
1473	  the current vCPU is discounted from the vCPU power. To account for
1474	  that, there can be a small performance impact.
1475
1476	  If in doubt, say N here.
1477
1478config ARCH_SUPPORTS_KEXEC
1479	def_bool PM_SLEEP_SMP
1480
1481config ARCH_SUPPORTS_KEXEC_FILE
1482	def_bool y
1483
1484config ARCH_SELECTS_KEXEC_FILE
1485	def_bool y
1486	depends on KEXEC_FILE
1487	select HAVE_IMA_KEXEC if IMA
1488
1489config ARCH_SUPPORTS_KEXEC_SIG
1490	def_bool y
1491
1492config ARCH_SUPPORTS_KEXEC_IMAGE_VERIFY_SIG
1493	def_bool y
1494
1495config ARCH_DEFAULT_KEXEC_IMAGE_VERIFY_SIG
1496	def_bool y
1497
1498config ARCH_SUPPORTS_CRASH_DUMP
1499	def_bool y
1500
1501config TRANS_TABLE
1502	def_bool y
1503	depends on HIBERNATION || KEXEC_CORE
1504
1505config XEN_DOM0
1506	def_bool y
1507	depends on XEN
1508
1509config XEN
1510	bool "Xen guest support on ARM64"
1511	depends on ARM64 && OF
1512	select SWIOTLB_XEN
1513	select PARAVIRT
1514	help
1515	  Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64.
1516
1517# include/linux/mmzone.h requires the following to be true:
1518#
1519#   MAX_ORDER + PAGE_SHIFT <= SECTION_SIZE_BITS
1520#
1521# so the maximum value of MAX_ORDER is SECTION_SIZE_BITS - PAGE_SHIFT:
1522#
1523#     | SECTION_SIZE_BITS |  PAGE_SHIFT  |  max MAX_ORDER  |  default MAX_ORDER |
1524# ----+-------------------+--------------+-----------------+--------------------+
1525# 4K  |       27          |      12      |       15        |         10         |
1526# 16K |       27          |      14      |       13        |         11         |
1527# 64K |       29          |      16      |       13        |         13         |
1528config ARCH_FORCE_MAX_ORDER
1529	int
1530	default "13" if ARM64_64K_PAGES
1531	default "11" if ARM64_16K_PAGES
1532	default "10"
1533	help
1534	  The kernel page allocator limits the size of maximal physically
1535	  contiguous allocations. The limit is called MAX_ORDER and it
1536	  defines the maximal power of two of number of pages that can be
1537	  allocated as a single contiguous block. This option allows
1538	  overriding the default setting when ability to allocate very
1539	  large blocks of physically contiguous memory is required.
1540
1541	  The maximal size of allocation cannot exceed the size of the
1542	  section, so the value of MAX_ORDER should satisfy
1543
1544	    MAX_ORDER + PAGE_SHIFT <= SECTION_SIZE_BITS
1545
1546	  Don't change if unsure.
1547
1548config UNMAP_KERNEL_AT_EL0
1549	bool "Unmap kernel when running in userspace (aka \"KAISER\")" if EXPERT
1550	default y
1551	help
1552	  Speculation attacks against some high-performance processors can
1553	  be used to bypass MMU permission checks and leak kernel data to
1554	  userspace. This can be defended against by unmapping the kernel
1555	  when running in userspace, mapping it back in on exception entry
1556	  via a trampoline page in the vector table.
1557
1558	  If unsure, say Y.
1559
1560config MITIGATE_SPECTRE_BRANCH_HISTORY
1561	bool "Mitigate Spectre style attacks against branch history" if EXPERT
1562	default y
1563	help
1564	  Speculation attacks against some high-performance processors can
1565	  make use of branch history to influence future speculation.
1566	  When taking an exception from user-space, a sequence of branches
1567	  or a firmware call overwrites the branch history.
1568
1569config RODATA_FULL_DEFAULT_ENABLED
1570	bool "Apply r/o permissions of VM areas also to their linear aliases"
1571	default y
1572	help
1573	  Apply read-only attributes of VM areas to the linear alias of
1574	  the backing pages as well. This prevents code or read-only data
1575	  from being modified (inadvertently or intentionally) via another
1576	  mapping of the same memory page. This additional enhancement can
1577	  be turned off at runtime by passing rodata=[off|on] (and turned on
1578	  with rodata=full if this option is set to 'n')
1579
1580	  This requires the linear region to be mapped down to pages,
1581	  which may adversely affect performance in some cases.
1582
1583config ARM64_SW_TTBR0_PAN
1584	bool "Emulate Privileged Access Never using TTBR0_EL1 switching"
1585	help
1586	  Enabling this option prevents the kernel from accessing
1587	  user-space memory directly by pointing TTBR0_EL1 to a reserved
1588	  zeroed area and reserved ASID. The user access routines
1589	  restore the valid TTBR0_EL1 temporarily.
1590
1591config ARM64_TAGGED_ADDR_ABI
1592	bool "Enable the tagged user addresses syscall ABI"
1593	default y
1594	help
1595	  When this option is enabled, user applications can opt in to a
1596	  relaxed ABI via prctl() allowing tagged addresses to be passed
1597	  to system calls as pointer arguments. For details, see
1598	  Documentation/arch/arm64/tagged-address-abi.rst.
1599
1600menuconfig COMPAT
1601	bool "Kernel support for 32-bit EL0"
1602	depends on ARM64_4K_PAGES || EXPERT
1603	select HAVE_UID16
1604	select OLD_SIGSUSPEND3
1605	select COMPAT_OLD_SIGACTION
1606	help
1607	  This option enables support for a 32-bit EL0 running under a 64-bit
1608	  kernel at EL1. AArch32-specific components such as system calls,
1609	  the user helper functions, VFP support and the ptrace interface are
1610	  handled appropriately by the kernel.
1611
1612	  If you use a page size other than 4KB (i.e, 16KB or 64KB), please be aware
1613	  that you will only be able to execute AArch32 binaries that were compiled
1614	  with page size aligned segments.
1615
1616	  If you want to execute 32-bit userspace applications, say Y.
1617
1618if COMPAT
1619
1620config KUSER_HELPERS
1621	bool "Enable kuser helpers page for 32-bit applications"
1622	default y
1623	help
1624	  Warning: disabling this option may break 32-bit user programs.
1625
1626	  Provide kuser helpers to compat tasks. The kernel provides
1627	  helper code to userspace in read only form at a fixed location
1628	  to allow userspace to be independent of the CPU type fitted to
1629	  the system. This permits binaries to be run on ARMv4 through
1630	  to ARMv8 without modification.
1631
1632	  See Documentation/arch/arm/kernel_user_helpers.rst for details.
1633
1634	  However, the fixed address nature of these helpers can be used
1635	  by ROP (return orientated programming) authors when creating
1636	  exploits.
1637
1638	  If all of the binaries and libraries which run on your platform
1639	  are built specifically for your platform, and make no use of
1640	  these helpers, then you can turn this option off to hinder
1641	  such exploits. However, in that case, if a binary or library
1642	  relying on those helpers is run, it will not function correctly.
1643
1644	  Say N here only if you are absolutely certain that you do not
1645	  need these helpers; otherwise, the safe option is to say Y.
1646
1647config COMPAT_VDSO
1648	bool "Enable vDSO for 32-bit applications"
1649	depends on !CPU_BIG_ENDIAN
1650	depends on (CC_IS_CLANG && LD_IS_LLD) || "$(CROSS_COMPILE_COMPAT)" != ""
1651	select GENERIC_COMPAT_VDSO
1652	default y
1653	help
1654	  Place in the process address space of 32-bit applications an
1655	  ELF shared object providing fast implementations of gettimeofday
1656	  and clock_gettime.
1657
1658	  You must have a 32-bit build of glibc 2.22 or later for programs
1659	  to seamlessly take advantage of this.
1660
1661config THUMB2_COMPAT_VDSO
1662	bool "Compile the 32-bit vDSO for Thumb-2 mode" if EXPERT
1663	depends on COMPAT_VDSO
1664	default y
1665	help
1666	  Compile the compat vDSO with '-mthumb -fomit-frame-pointer' if y,
1667	  otherwise with '-marm'.
1668
1669config COMPAT_ALIGNMENT_FIXUPS
1670	bool "Fix up misaligned multi-word loads and stores in user space"
1671
1672menuconfig ARMV8_DEPRECATED
1673	bool "Emulate deprecated/obsolete ARMv8 instructions"
1674	depends on SYSCTL
1675	help
1676	  Legacy software support may require certain instructions
1677	  that have been deprecated or obsoleted in the architecture.
1678
1679	  Enable this config to enable selective emulation of these
1680	  features.
1681
1682	  If unsure, say Y
1683
1684if ARMV8_DEPRECATED
1685
1686config SWP_EMULATION
1687	bool "Emulate SWP/SWPB instructions"
1688	help
1689	  ARMv8 obsoletes the use of A32 SWP/SWPB instructions such that
1690	  they are always undefined. Say Y here to enable software
1691	  emulation of these instructions for userspace using LDXR/STXR.
1692	  This feature can be controlled at runtime with the abi.swp
1693	  sysctl which is disabled by default.
1694
1695	  In some older versions of glibc [<=2.8] SWP is used during futex
1696	  trylock() operations with the assumption that the code will not
1697	  be preempted. This invalid assumption may be more likely to fail
1698	  with SWP emulation enabled, leading to deadlock of the user
1699	  application.
1700
1701	  NOTE: when accessing uncached shared regions, LDXR/STXR rely
1702	  on an external transaction monitoring block called a global
1703	  monitor to maintain update atomicity. If your system does not
1704	  implement a global monitor, this option can cause programs that
1705	  perform SWP operations to uncached memory to deadlock.
1706
1707	  If unsure, say Y
1708
1709config CP15_BARRIER_EMULATION
1710	bool "Emulate CP15 Barrier instructions"
1711	help
1712	  The CP15 barrier instructions - CP15ISB, CP15DSB, and
1713	  CP15DMB - are deprecated in ARMv8 (and ARMv7). It is
1714	  strongly recommended to use the ISB, DSB, and DMB
1715	  instructions instead.
1716
1717	  Say Y here to enable software emulation of these
1718	  instructions for AArch32 userspace code. When this option is
1719	  enabled, CP15 barrier usage is traced which can help
1720	  identify software that needs updating. This feature can be
1721	  controlled at runtime with the abi.cp15_barrier sysctl.
1722
1723	  If unsure, say Y
1724
1725config SETEND_EMULATION
1726	bool "Emulate SETEND instruction"
1727	help
1728	  The SETEND instruction alters the data-endianness of the
1729	  AArch32 EL0, and is deprecated in ARMv8.
1730
1731	  Say Y here to enable software emulation of the instruction
1732	  for AArch32 userspace code. This feature can be controlled
1733	  at runtime with the abi.setend sysctl.
1734
1735	  Note: All the cpus on the system must have mixed endian support at EL0
1736	  for this feature to be enabled. If a new CPU - which doesn't support mixed
1737	  endian - is hotplugged in after this feature has been enabled, there could
1738	  be unexpected results in the applications.
1739
1740	  If unsure, say Y
1741endif # ARMV8_DEPRECATED
1742
1743endif # COMPAT
1744
1745menu "ARMv8.1 architectural features"
1746
1747config ARM64_HW_AFDBM
1748	bool "Support for hardware updates of the Access and Dirty page flags"
1749	default y
1750	help
1751	  The ARMv8.1 architecture extensions introduce support for
1752	  hardware updates of the access and dirty information in page
1753	  table entries. When enabled in TCR_EL1 (HA and HD bits) on
1754	  capable processors, accesses to pages with PTE_AF cleared will
1755	  set this bit instead of raising an access flag fault.
1756	  Similarly, writes to read-only pages with the DBM bit set will
1757	  clear the read-only bit (AP[2]) instead of raising a
1758	  permission fault.
1759
1760	  Kernels built with this configuration option enabled continue
1761	  to work on pre-ARMv8.1 hardware and the performance impact is
1762	  minimal. If unsure, say Y.
1763
1764config ARM64_PAN
1765	bool "Enable support for Privileged Access Never (PAN)"
1766	default y
1767	help
1768	  Privileged Access Never (PAN; part of the ARMv8.1 Extensions)
1769	  prevents the kernel or hypervisor from accessing user-space (EL0)
1770	  memory directly.
1771
1772	  Choosing this option will cause any unprotected (not using
1773	  copy_to_user et al) memory access to fail with a permission fault.
1774
1775	  The feature is detected at runtime, and will remain as a 'nop'
1776	  instruction if the cpu does not implement the feature.
1777
1778config AS_HAS_LSE_ATOMICS
1779	def_bool $(as-instr,.arch_extension lse)
1780
1781config ARM64_LSE_ATOMICS
1782	bool
1783	default ARM64_USE_LSE_ATOMICS
1784	depends on AS_HAS_LSE_ATOMICS
1785
1786config ARM64_USE_LSE_ATOMICS
1787	bool "Atomic instructions"
1788	default y
1789	help
1790	  As part of the Large System Extensions, ARMv8.1 introduces new
1791	  atomic instructions that are designed specifically to scale in
1792	  very large systems.
1793
1794	  Say Y here to make use of these instructions for the in-kernel
1795	  atomic routines. This incurs a small overhead on CPUs that do
1796	  not support these instructions and requires the kernel to be
1797	  built with binutils >= 2.25 in order for the new instructions
1798	  to be used.
1799
1800endmenu # "ARMv8.1 architectural features"
1801
1802menu "ARMv8.2 architectural features"
1803
1804config AS_HAS_ARMV8_2
1805	def_bool $(cc-option,-Wa$(comma)-march=armv8.2-a)
1806
1807config AS_HAS_SHA3
1808	def_bool $(as-instr,.arch armv8.2-a+sha3)
1809
1810config ARM64_PMEM
1811	bool "Enable support for persistent memory"
1812	select ARCH_HAS_PMEM_API
1813	select ARCH_HAS_UACCESS_FLUSHCACHE
1814	help
1815	  Say Y to enable support for the persistent memory API based on the
1816	  ARMv8.2 DCPoP feature.
1817
1818	  The feature is detected at runtime, and the kernel will use DC CVAC
1819	  operations if DC CVAP is not supported (following the behaviour of
1820	  DC CVAP itself if the system does not define a point of persistence).
1821
1822config ARM64_RAS_EXTN
1823	bool "Enable support for RAS CPU Extensions"
1824	default y
1825	help
1826	  CPUs that support the Reliability, Availability and Serviceability
1827	  (RAS) Extensions, part of ARMv8.2 are able to track faults and
1828	  errors, classify them and report them to software.
1829
1830	  On CPUs with these extensions system software can use additional
1831	  barriers to determine if faults are pending and read the
1832	  classification from a new set of registers.
1833
1834	  Selecting this feature will allow the kernel to use these barriers
1835	  and access the new registers if the system supports the extension.
1836	  Platform RAS features may additionally depend on firmware support.
1837
1838config ARM64_CNP
1839	bool "Enable support for Common Not Private (CNP) translations"
1840	default y
1841	depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
1842	help
1843	  Common Not Private (CNP) allows translation table entries to
1844	  be shared between different PEs in the same inner shareable
1845	  domain, so the hardware can use this fact to optimise the
1846	  caching of such entries in the TLB.
1847
1848	  Selecting this option allows the CNP feature to be detected
1849	  at runtime, and does not affect PEs that do not implement
1850	  this feature.
1851
1852endmenu # "ARMv8.2 architectural features"
1853
1854menu "ARMv8.3 architectural features"
1855
1856config ARM64_PTR_AUTH
1857	bool "Enable support for pointer authentication"
1858	default y
1859	help
1860	  Pointer authentication (part of the ARMv8.3 Extensions) provides
1861	  instructions for signing and authenticating pointers against secret
1862	  keys, which can be used to mitigate Return Oriented Programming (ROP)
1863	  and other attacks.
1864
1865	  This option enables these instructions at EL0 (i.e. for userspace).
1866	  Choosing this option will cause the kernel to initialise secret keys
1867	  for each process at exec() time, with these keys being
1868	  context-switched along with the process.
1869
1870	  The feature is detected at runtime. If the feature is not present in
1871	  hardware it will not be advertised to userspace/KVM guest nor will it
1872	  be enabled.
1873
1874	  If the feature is present on the boot CPU but not on a late CPU, then
1875	  the late CPU will be parked. Also, if the boot CPU does not have
1876	  address auth and the late CPU has then the late CPU will still boot
1877	  but with the feature disabled. On such a system, this option should
1878	  not be selected.
1879
1880config ARM64_PTR_AUTH_KERNEL
1881	bool "Use pointer authentication for kernel"
1882	default y
1883	depends on ARM64_PTR_AUTH
1884	depends on (CC_HAS_SIGN_RETURN_ADDRESS || CC_HAS_BRANCH_PROT_PAC_RET) && AS_HAS_ARMV8_3
1885	# Modern compilers insert a .note.gnu.property section note for PAC
1886	# which is only understood by binutils starting with version 2.33.1.
1887	depends on LD_IS_LLD || LD_VERSION >= 23301 || (CC_IS_GCC && GCC_VERSION < 90100)
1888	depends on !CC_IS_CLANG || AS_HAS_CFI_NEGATE_RA_STATE
1889	depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_ARGS)
1890	help
1891	  If the compiler supports the -mbranch-protection or
1892	  -msign-return-address flag (e.g. GCC 7 or later), then this option
1893	  will cause the kernel itself to be compiled with return address
1894	  protection. In this case, and if the target hardware is known to
1895	  support pointer authentication, then CONFIG_STACKPROTECTOR can be
1896	  disabled with minimal loss of protection.
1897
1898	  This feature works with FUNCTION_GRAPH_TRACER option only if
1899	  DYNAMIC_FTRACE_WITH_ARGS is enabled.
1900
1901config CC_HAS_BRANCH_PROT_PAC_RET
1902	# GCC 9 or later, clang 8 or later
1903	def_bool $(cc-option,-mbranch-protection=pac-ret+leaf)
1904
1905config CC_HAS_SIGN_RETURN_ADDRESS
1906	# GCC 7, 8
1907	def_bool $(cc-option,-msign-return-address=all)
1908
1909config AS_HAS_ARMV8_3
1910	def_bool $(cc-option,-Wa$(comma)-march=armv8.3-a)
1911
1912config AS_HAS_CFI_NEGATE_RA_STATE
1913	def_bool $(as-instr,.cfi_startproc\n.cfi_negate_ra_state\n.cfi_endproc\n)
1914
1915config AS_HAS_LDAPR
1916	def_bool $(as-instr,.arch_extension rcpc)
1917
1918endmenu # "ARMv8.3 architectural features"
1919
1920menu "ARMv8.4 architectural features"
1921
1922config ARM64_AMU_EXTN
1923	bool "Enable support for the Activity Monitors Unit CPU extension"
1924	default y
1925	help
1926	  The activity monitors extension is an optional extension introduced
1927	  by the ARMv8.4 CPU architecture. This enables support for version 1
1928	  of the activity monitors architecture, AMUv1.
1929
1930	  To enable the use of this extension on CPUs that implement it, say Y.
1931
1932	  Note that for architectural reasons, firmware _must_ implement AMU
1933	  support when running on CPUs that present the activity monitors
1934	  extension. The required support is present in:
1935	    * Version 1.5 and later of the ARM Trusted Firmware
1936
1937	  For kernels that have this configuration enabled but boot with broken
1938	  firmware, you may need to say N here until the firmware is fixed.
1939	  Otherwise you may experience firmware panics or lockups when
1940	  accessing the counter registers. Even if you are not observing these
1941	  symptoms, the values returned by the register reads might not
1942	  correctly reflect reality. Most commonly, the value read will be 0,
1943	  indicating that the counter is not enabled.
1944
1945config AS_HAS_ARMV8_4
1946	def_bool $(cc-option,-Wa$(comma)-march=armv8.4-a)
1947
1948config ARM64_TLB_RANGE
1949	bool "Enable support for tlbi range feature"
1950	default y
1951	depends on AS_HAS_ARMV8_4
1952	help
1953	  ARMv8.4-TLBI provides TLBI invalidation instruction that apply to a
1954	  range of input addresses.
1955
1956	  The feature introduces new assembly instructions, and they were
1957	  support when binutils >= 2.30.
1958
1959endmenu # "ARMv8.4 architectural features"
1960
1961menu "ARMv8.5 architectural features"
1962
1963config AS_HAS_ARMV8_5
1964	def_bool $(cc-option,-Wa$(comma)-march=armv8.5-a)
1965
1966config ARM64_BTI
1967	bool "Branch Target Identification support"
1968	default y
1969	help
1970	  Branch Target Identification (part of the ARMv8.5 Extensions)
1971	  provides a mechanism to limit the set of locations to which computed
1972	  branch instructions such as BR or BLR can jump.
1973
1974	  To make use of BTI on CPUs that support it, say Y.
1975
1976	  BTI is intended to provide complementary protection to other control
1977	  flow integrity protection mechanisms, such as the Pointer
1978	  authentication mechanism provided as part of the ARMv8.3 Extensions.
1979	  For this reason, it does not make sense to enable this option without
1980	  also enabling support for pointer authentication.  Thus, when
1981	  enabling this option you should also select ARM64_PTR_AUTH=y.
1982
1983	  Userspace binaries must also be specifically compiled to make use of
1984	  this mechanism.  If you say N here or the hardware does not support
1985	  BTI, such binaries can still run, but you get no additional
1986	  enforcement of branch destinations.
1987
1988config ARM64_BTI_KERNEL
1989	bool "Use Branch Target Identification for kernel"
1990	default y
1991	depends on ARM64_BTI
1992	depends on ARM64_PTR_AUTH_KERNEL
1993	depends on CC_HAS_BRANCH_PROT_PAC_RET_BTI
1994	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94697
1995	depends on !CC_IS_GCC || GCC_VERSION >= 100100
1996	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106671
1997	depends on !CC_IS_GCC
1998	# https://github.com/llvm/llvm-project/commit/a88c722e687e6780dcd6a58718350dc76fcc4cc9
1999	depends on !CC_IS_CLANG || CLANG_VERSION >= 120000
2000	depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_ARGS)
2001	help
2002	  Build the kernel with Branch Target Identification annotations
2003	  and enable enforcement of this for kernel code. When this option
2004	  is enabled and the system supports BTI all kernel code including
2005	  modular code must have BTI enabled.
2006
2007config CC_HAS_BRANCH_PROT_PAC_RET_BTI
2008	# GCC 9 or later, clang 8 or later
2009	def_bool $(cc-option,-mbranch-protection=pac-ret+leaf+bti)
2010
2011config ARM64_E0PD
2012	bool "Enable support for E0PD"
2013	default y
2014	help
2015	  E0PD (part of the ARMv8.5 extensions) allows us to ensure
2016	  that EL0 accesses made via TTBR1 always fault in constant time,
2017	  providing similar benefits to KASLR as those provided by KPTI, but
2018	  with lower overhead and without disrupting legitimate access to
2019	  kernel memory such as SPE.
2020
2021	  This option enables E0PD for TTBR1 where available.
2022
2023config ARM64_AS_HAS_MTE
2024	# Initial support for MTE went in binutils 2.32.0, checked with
2025	# ".arch armv8.5-a+memtag" below. However, this was incomplete
2026	# as a late addition to the final architecture spec (LDGM/STGM)
2027	# is only supported in the newer 2.32.x and 2.33 binutils
2028	# versions, hence the extra "stgm" instruction check below.
2029	def_bool $(as-instr,.arch armv8.5-a+memtag\nstgm xzr$(comma)[x0])
2030
2031config ARM64_MTE
2032	bool "Memory Tagging Extension support"
2033	default y
2034	depends on ARM64_AS_HAS_MTE && ARM64_TAGGED_ADDR_ABI
2035	depends on AS_HAS_ARMV8_5
2036	depends on AS_HAS_LSE_ATOMICS
2037	# Required for tag checking in the uaccess routines
2038	depends on ARM64_PAN
2039	select ARCH_HAS_SUBPAGE_FAULTS
2040	select ARCH_USES_HIGH_VMA_FLAGS
2041	select ARCH_USES_PG_ARCH_X
2042	help
2043	  Memory Tagging (part of the ARMv8.5 Extensions) provides
2044	  architectural support for run-time, always-on detection of
2045	  various classes of memory error to aid with software debugging
2046	  to eliminate vulnerabilities arising from memory-unsafe
2047	  languages.
2048
2049	  This option enables the support for the Memory Tagging
2050	  Extension at EL0 (i.e. for userspace).
2051
2052	  Selecting this option allows the feature to be detected at
2053	  runtime. Any secondary CPU not implementing this feature will
2054	  not be allowed a late bring-up.
2055
2056	  Userspace binaries that want to use this feature must
2057	  explicitly opt in. The mechanism for the userspace is
2058	  described in:
2059
2060	  Documentation/arch/arm64/memory-tagging-extension.rst.
2061
2062endmenu # "ARMv8.5 architectural features"
2063
2064menu "ARMv8.7 architectural features"
2065
2066config ARM64_EPAN
2067	bool "Enable support for Enhanced Privileged Access Never (EPAN)"
2068	default y
2069	depends on ARM64_PAN
2070	help
2071	  Enhanced Privileged Access Never (EPAN) allows Privileged
2072	  Access Never to be used with Execute-only mappings.
2073
2074	  The feature is detected at runtime, and will remain disabled
2075	  if the cpu does not implement the feature.
2076endmenu # "ARMv8.7 architectural features"
2077
2078config ARM64_SVE
2079	bool "ARM Scalable Vector Extension support"
2080	default y
2081	help
2082	  The Scalable Vector Extension (SVE) is an extension to the AArch64
2083	  execution state which complements and extends the SIMD functionality
2084	  of the base architecture to support much larger vectors and to enable
2085	  additional vectorisation opportunities.
2086
2087	  To enable use of this extension on CPUs that implement it, say Y.
2088
2089	  On CPUs that support the SVE2 extensions, this option will enable
2090	  those too.
2091
2092	  Note that for architectural reasons, firmware _must_ implement SVE
2093	  support when running on SVE capable hardware.  The required support
2094	  is present in:
2095
2096	    * version 1.5 and later of the ARM Trusted Firmware
2097	    * the AArch64 boot wrapper since commit 5e1261e08abf
2098	      ("bootwrapper: SVE: Enable SVE for EL2 and below").
2099
2100	  For other firmware implementations, consult the firmware documentation
2101	  or vendor.
2102
2103	  If you need the kernel to boot on SVE-capable hardware with broken
2104	  firmware, you may need to say N here until you get your firmware
2105	  fixed.  Otherwise, you may experience firmware panics or lockups when
2106	  booting the kernel.  If unsure and you are not observing these
2107	  symptoms, you should assume that it is safe to say Y.
2108
2109config ARM64_SME
2110	bool "ARM Scalable Matrix Extension support"
2111	default y
2112	depends on ARM64_SVE
2113	help
2114	  The Scalable Matrix Extension (SME) is an extension to the AArch64
2115	  execution state which utilises a substantial subset of the SVE
2116	  instruction set, together with the addition of new architectural
2117	  register state capable of holding two dimensional matrix tiles to
2118	  enable various matrix operations.
2119
2120config ARM64_PSEUDO_NMI
2121	bool "Support for NMI-like interrupts"
2122	select ARM_GIC_V3
2123	help
2124	  Adds support for mimicking Non-Maskable Interrupts through the use of
2125	  GIC interrupt priority. This support requires version 3 or later of
2126	  ARM GIC.
2127
2128	  This high priority configuration for interrupts needs to be
2129	  explicitly enabled by setting the kernel parameter
2130	  "irqchip.gicv3_pseudo_nmi" to 1.
2131
2132	  If unsure, say N
2133
2134if ARM64_PSEUDO_NMI
2135config ARM64_DEBUG_PRIORITY_MASKING
2136	bool "Debug interrupt priority masking"
2137	help
2138	  This adds runtime checks to functions enabling/disabling
2139	  interrupts when using priority masking. The additional checks verify
2140	  the validity of ICC_PMR_EL1 when calling concerned functions.
2141
2142	  If unsure, say N
2143endif # ARM64_PSEUDO_NMI
2144
2145config RELOCATABLE
2146	bool "Build a relocatable kernel image" if EXPERT
2147	select ARCH_HAS_RELR
2148	default y
2149	help
2150	  This builds the kernel as a Position Independent Executable (PIE),
2151	  which retains all relocation metadata required to relocate the
2152	  kernel binary at runtime to a different virtual address than the
2153	  address it was linked at.
2154	  Since AArch64 uses the RELA relocation format, this requires a
2155	  relocation pass at runtime even if the kernel is loaded at the
2156	  same address it was linked at.
2157
2158config RANDOMIZE_BASE
2159	bool "Randomize the address of the kernel image"
2160	select RELOCATABLE
2161	help
2162	  Randomizes the virtual address at which the kernel image is
2163	  loaded, as a security feature that deters exploit attempts
2164	  relying on knowledge of the location of kernel internals.
2165
2166	  It is the bootloader's job to provide entropy, by passing a
2167	  random u64 value in /chosen/kaslr-seed at kernel entry.
2168
2169	  When booting via the UEFI stub, it will invoke the firmware's
2170	  EFI_RNG_PROTOCOL implementation (if available) to supply entropy
2171	  to the kernel proper. In addition, it will randomise the physical
2172	  location of the kernel Image as well.
2173
2174	  If unsure, say N.
2175
2176config RANDOMIZE_MODULE_REGION_FULL
2177	bool "Randomize the module region over a 2 GB range"
2178	depends on RANDOMIZE_BASE
2179	default y
2180	help
2181	  Randomizes the location of the module region inside a 2 GB window
2182	  covering the core kernel. This way, it is less likely for modules
2183	  to leak information about the location of core kernel data structures
2184	  but it does imply that function calls between modules and the core
2185	  kernel will need to be resolved via veneers in the module PLT.
2186
2187	  When this option is not set, the module region will be randomized over
2188	  a limited range that contains the [_stext, _etext] interval of the
2189	  core kernel, so branch relocations are almost always in range unless
2190	  the region is exhausted. In this particular case of region
2191	  exhaustion, modules might be able to fall back to a larger 2GB area.
2192
2193config CC_HAVE_STACKPROTECTOR_SYSREG
2194	def_bool $(cc-option,-mstack-protector-guard=sysreg -mstack-protector-guard-reg=sp_el0 -mstack-protector-guard-offset=0)
2195
2196config STACKPROTECTOR_PER_TASK
2197	def_bool y
2198	depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_SYSREG
2199
2200config UNWIND_PATCH_PAC_INTO_SCS
2201	bool "Enable shadow call stack dynamically using code patching"
2202	# needs Clang with https://reviews.llvm.org/D111780 incorporated
2203	depends on CC_IS_CLANG && CLANG_VERSION >= 150000
2204	depends on ARM64_PTR_AUTH_KERNEL && CC_HAS_BRANCH_PROT_PAC_RET
2205	depends on SHADOW_CALL_STACK
2206	select UNWIND_TABLES
2207	select DYNAMIC_SCS
2208
2209endmenu # "Kernel Features"
2210
2211menu "Boot options"
2212
2213config ARM64_ACPI_PARKING_PROTOCOL
2214	bool "Enable support for the ARM64 ACPI parking protocol"
2215	depends on ACPI
2216	help
2217	  Enable support for the ARM64 ACPI parking protocol. If disabled
2218	  the kernel will not allow booting through the ARM64 ACPI parking
2219	  protocol even if the corresponding data is present in the ACPI
2220	  MADT table.
2221
2222config CMDLINE
2223	string "Default kernel command string"
2224	default ""
2225	help
2226	  Provide a set of default command-line options at build time by
2227	  entering them here. As a minimum, you should specify the the
2228	  root device (e.g. root=/dev/nfs).
2229
2230choice
2231	prompt "Kernel command line type" if CMDLINE != ""
2232	default CMDLINE_FROM_BOOTLOADER
2233	help
2234	  Choose how the kernel will handle the provided default kernel
2235	  command line string.
2236
2237config CMDLINE_FROM_BOOTLOADER
2238	bool "Use bootloader kernel arguments if available"
2239	help
2240	  Uses the command-line options passed by the boot loader. If
2241	  the boot loader doesn't provide any, the default kernel command
2242	  string provided in CMDLINE will be used.
2243
2244config CMDLINE_FORCE
2245	bool "Always use the default kernel command string"
2246	help
2247	  Always use the default kernel command string, even if the boot
2248	  loader passes other arguments to the kernel.
2249	  This is useful if you cannot or don't want to change the
2250	  command-line options your boot loader passes to the kernel.
2251
2252endchoice
2253
2254config EFI_STUB
2255	bool
2256
2257config EFI
2258	bool "UEFI runtime support"
2259	depends on OF && !CPU_BIG_ENDIAN
2260	depends on KERNEL_MODE_NEON
2261	select ARCH_SUPPORTS_ACPI
2262	select LIBFDT
2263	select UCS2_STRING
2264	select EFI_PARAMS_FROM_FDT
2265	select EFI_RUNTIME_WRAPPERS
2266	select EFI_STUB
2267	select EFI_GENERIC_STUB
2268	imply IMA_SECURE_AND_OR_TRUSTED_BOOT
2269	default y
2270	help
2271	  This option provides support for runtime services provided
2272	  by UEFI firmware (such as non-volatile variables, realtime
2273	  clock, and platform reset). A UEFI stub is also provided to
2274	  allow the kernel to be booted as an EFI application. This
2275	  is only useful on systems that have UEFI firmware.
2276
2277config DMI
2278	bool "Enable support for SMBIOS (DMI) tables"
2279	depends on EFI
2280	default y
2281	help
2282	  This enables SMBIOS/DMI feature for systems.
2283
2284	  This option is only useful on systems that have UEFI firmware.
2285	  However, even with this option, the resultant kernel should
2286	  continue to boot on existing non-UEFI platforms.
2287
2288endmenu # "Boot options"
2289
2290menu "Power management options"
2291
2292source "kernel/power/Kconfig"
2293
2294config ARCH_HIBERNATION_POSSIBLE
2295	def_bool y
2296	depends on CPU_PM
2297
2298config ARCH_HIBERNATION_HEADER
2299	def_bool y
2300	depends on HIBERNATION
2301
2302config ARCH_SUSPEND_POSSIBLE
2303	def_bool y
2304
2305endmenu # "Power management options"
2306
2307menu "CPU Power Management"
2308
2309source "drivers/cpuidle/Kconfig"
2310
2311source "drivers/cpufreq/Kconfig"
2312
2313endmenu # "CPU Power Management"
2314
2315source "drivers/acpi/Kconfig"
2316
2317source "arch/arm64/kvm/Kconfig"
2318
2319