xref: /openbmc/linux/arch/arm64/Kconfig (revision 93696d8f)
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_IS_CLANG || !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_WORKAROUND_SPECULATIVE_UNPRIV_LOAD
1041	bool
1042
1043config ARM64_ERRATUM_2966298
1044	bool "Cortex-A520: 2966298: workaround for speculatively executed unprivileged load"
1045	select ARM64_WORKAROUND_SPECULATIVE_UNPRIV_LOAD
1046	default y
1047	help
1048	  This option adds the workaround for ARM Cortex-A520 erratum 2966298.
1049
1050	  On an affected Cortex-A520 core, a speculatively executed unprivileged
1051	  load might leak data from a privileged level via a cache side channel.
1052
1053	  Work around this problem by executing a TLBI before returning to EL0.
1054
1055	  If unsure, say Y.
1056
1057config ARM64_ERRATUM_3117295
1058	bool "Cortex-A510: 3117295: workaround for speculatively executed unprivileged load"
1059	select ARM64_WORKAROUND_SPECULATIVE_UNPRIV_LOAD
1060	default y
1061	help
1062	  This option adds the workaround for ARM Cortex-A510 erratum 3117295.
1063
1064	  On an affected Cortex-A510 core, a speculatively executed unprivileged
1065	  load might leak data from a privileged level via a cache side channel.
1066
1067	  Work around this problem by executing a TLBI before returning to EL0.
1068
1069	  If unsure, say Y.
1070
1071config ARM64_WORKAROUND_SPECULATIVE_SSBS
1072	bool
1073
1074config ARM64_ERRATUM_3194386
1075	bool "Cortex-X4: 3194386: workaround for MSR SSBS not self-synchronizing"
1076	select ARM64_WORKAROUND_SPECULATIVE_SSBS
1077	default y
1078	help
1079	  This option adds the workaround for ARM Cortex-X4 erratum 3194386.
1080
1081	  On affected cores "MSR SSBS, #0" instructions may not affect
1082	  subsequent speculative instructions, which may permit unexepected
1083	  speculative store bypassing.
1084
1085	  Work around this problem by placing a speculation barrier after
1086	  kernel changes to SSBS. The presence of the SSBS special-purpose
1087	  register is hidden from hwcaps and EL0 reads of ID_AA64PFR1_EL1, such
1088	  that userspace will use the PR_SPEC_STORE_BYPASS prctl to change
1089	  SSBS.
1090
1091	  If unsure, say Y.
1092
1093config ARM64_ERRATUM_3312417
1094	bool "Neoverse-V3: 3312417: workaround for MSR SSBS not self-synchronizing"
1095	select ARM64_WORKAROUND_SPECULATIVE_SSBS
1096	default y
1097	help
1098	  This option adds the workaround for ARM Neoverse-V3 erratum 3312417.
1099
1100	  On affected cores "MSR SSBS, #0" instructions may not affect
1101	  subsequent speculative instructions, which may permit unexepected
1102	  speculative store bypassing.
1103
1104	  Work around this problem by placing a speculation barrier after
1105	  kernel changes to SSBS. The presence of the SSBS special-purpose
1106	  register is hidden from hwcaps and EL0 reads of ID_AA64PFR1_EL1, such
1107	  that userspace will use the PR_SPEC_STORE_BYPASS prctl to change
1108	  SSBS.
1109
1110	  If unsure, say Y.
1111
1112
1113config CAVIUM_ERRATUM_22375
1114	bool "Cavium erratum 22375, 24313"
1115	default y
1116	help
1117	  Enable workaround for errata 22375 and 24313.
1118
1119	  This implements two gicv3-its errata workarounds for ThunderX. Both
1120	  with a small impact affecting only ITS table allocation.
1121
1122	    erratum 22375: only alloc 8MB table size
1123	    erratum 24313: ignore memory access type
1124
1125	  The fixes are in ITS initialization and basically ignore memory access
1126	  type and table size provided by the TYPER and BASER registers.
1127
1128	  If unsure, say Y.
1129
1130config CAVIUM_ERRATUM_23144
1131	bool "Cavium erratum 23144: ITS SYNC hang on dual socket system"
1132	depends on NUMA
1133	default y
1134	help
1135	  ITS SYNC command hang for cross node io and collections/cpu mapping.
1136
1137	  If unsure, say Y.
1138
1139config CAVIUM_ERRATUM_23154
1140	bool "Cavium errata 23154 and 38545: GICv3 lacks HW synchronisation"
1141	default y
1142	help
1143	  The ThunderX GICv3 implementation requires a modified version for
1144	  reading the IAR status to ensure data synchronization
1145	  (access to icc_iar1_el1 is not sync'ed before and after).
1146
1147	  It also suffers from erratum 38545 (also present on Marvell's
1148	  OcteonTX and OcteonTX2), resulting in deactivated interrupts being
1149	  spuriously presented to the CPU interface.
1150
1151	  If unsure, say Y.
1152
1153config CAVIUM_ERRATUM_27456
1154	bool "Cavium erratum 27456: Broadcast TLBI instructions may cause icache corruption"
1155	default y
1156	help
1157	  On ThunderX T88 pass 1.x through 2.1 parts, broadcast TLBI
1158	  instructions may cause the icache to become corrupted if it
1159	  contains data for a non-current ASID.  The fix is to
1160	  invalidate the icache when changing the mm context.
1161
1162	  If unsure, say Y.
1163
1164config CAVIUM_ERRATUM_30115
1165	bool "Cavium erratum 30115: Guest may disable interrupts in host"
1166	default y
1167	help
1168	  On ThunderX T88 pass 1.x through 2.2, T81 pass 1.0 through
1169	  1.2, and T83 Pass 1.0, KVM guest execution may disable
1170	  interrupts in host. Trapping both GICv3 group-0 and group-1
1171	  accesses sidesteps the issue.
1172
1173	  If unsure, say Y.
1174
1175config CAVIUM_TX2_ERRATUM_219
1176	bool "Cavium ThunderX2 erratum 219: PRFM between TTBR change and ISB fails"
1177	default y
1178	help
1179	  On Cavium ThunderX2, a load, store or prefetch instruction between a
1180	  TTBR update and the corresponding context synchronizing operation can
1181	  cause a spurious Data Abort to be delivered to any hardware thread in
1182	  the CPU core.
1183
1184	  Work around the issue by avoiding the problematic code sequence and
1185	  trapping KVM guest TTBRx_EL1 writes to EL2 when SMT is enabled. The
1186	  trap handler performs the corresponding register access, skips the
1187	  instruction and ensures context synchronization by virtue of the
1188	  exception return.
1189
1190	  If unsure, say Y.
1191
1192config FUJITSU_ERRATUM_010001
1193	bool "Fujitsu-A64FX erratum E#010001: Undefined fault may occur wrongly"
1194	default y
1195	help
1196	  This option adds a workaround for Fujitsu-A64FX erratum E#010001.
1197	  On some variants of the Fujitsu-A64FX cores ver(1.0, 1.1), memory
1198	  accesses may cause undefined fault (Data abort, DFSC=0b111111).
1199	  This fault occurs under a specific hardware condition when a
1200	  load/store instruction performs an address translation using:
1201	  case-1  TTBR0_EL1 with TCR_EL1.NFD0 == 1.
1202	  case-2  TTBR0_EL2 with TCR_EL2.NFD0 == 1.
1203	  case-3  TTBR1_EL1 with TCR_EL1.NFD1 == 1.
1204	  case-4  TTBR1_EL2 with TCR_EL2.NFD1 == 1.
1205
1206	  The workaround is to ensure these bits are clear in TCR_ELx.
1207	  The workaround only affects the Fujitsu-A64FX.
1208
1209	  If unsure, say Y.
1210
1211config HISILICON_ERRATUM_161600802
1212	bool "Hip07 161600802: Erroneous redistributor VLPI base"
1213	default y
1214	help
1215	  The HiSilicon Hip07 SoC uses the wrong redistributor base
1216	  when issued ITS commands such as VMOVP and VMAPP, and requires
1217	  a 128kB offset to be applied to the target address in this commands.
1218
1219	  If unsure, say Y.
1220
1221config QCOM_FALKOR_ERRATUM_1003
1222	bool "Falkor E1003: Incorrect translation due to ASID change"
1223	default y
1224	help
1225	  On Falkor v1, an incorrect ASID may be cached in the TLB when ASID
1226	  and BADDR are changed together in TTBRx_EL1. Since we keep the ASID
1227	  in TTBR1_EL1, this situation only occurs in the entry trampoline and
1228	  then only for entries in the walk cache, since the leaf translation
1229	  is unchanged. Work around the erratum by invalidating the walk cache
1230	  entries for the trampoline before entering the kernel proper.
1231
1232config QCOM_FALKOR_ERRATUM_1009
1233	bool "Falkor E1009: Prematurely complete a DSB after a TLBI"
1234	default y
1235	select ARM64_WORKAROUND_REPEAT_TLBI
1236	help
1237	  On Falkor v1, the CPU may prematurely complete a DSB following a
1238	  TLBI xxIS invalidate maintenance operation. Repeat the TLBI operation
1239	  one more time to fix the issue.
1240
1241	  If unsure, say Y.
1242
1243config QCOM_QDF2400_ERRATUM_0065
1244	bool "QDF2400 E0065: Incorrect GITS_TYPER.ITT_Entry_size"
1245	default y
1246	help
1247	  On Qualcomm Datacenter Technologies QDF2400 SoC, ITS hardware reports
1248	  ITE size incorrectly. The GITS_TYPER.ITT_Entry_size field should have
1249	  been indicated as 16Bytes (0xf), not 8Bytes (0x7).
1250
1251	  If unsure, say Y.
1252
1253config QCOM_FALKOR_ERRATUM_E1041
1254	bool "Falkor E1041: Speculative instruction fetches might cause errant memory access"
1255	default y
1256	help
1257	  Falkor CPU may speculatively fetch instructions from an improper
1258	  memory location when MMU translation is changed from SCTLR_ELn[M]=1
1259	  to SCTLR_ELn[M]=0. Prefix an ISB instruction to fix the problem.
1260
1261	  If unsure, say Y.
1262
1263config NVIDIA_CARMEL_CNP_ERRATUM
1264	bool "NVIDIA Carmel CNP: CNP on Carmel semantically different than ARM cores"
1265	default y
1266	help
1267	  If CNP is enabled on Carmel cores, non-sharable TLBIs on a core will not
1268	  invalidate shared TLB entries installed by a different core, as it would
1269	  on standard ARM cores.
1270
1271	  If unsure, say Y.
1272
1273config ROCKCHIP_ERRATUM_3588001
1274	bool "Rockchip 3588001: GIC600 can not support shareability attributes"
1275	default y
1276	help
1277	  The Rockchip RK3588 GIC600 SoC integration does not support ACE/ACE-lite.
1278	  This means, that its sharability feature may not be used, even though it
1279	  is supported by the IP itself.
1280
1281	  If unsure, say Y.
1282
1283config SOCIONEXT_SYNQUACER_PREITS
1284	bool "Socionext Synquacer: Workaround for GICv3 pre-ITS"
1285	default y
1286	help
1287	  Socionext Synquacer SoCs implement a separate h/w block to generate
1288	  MSI doorbell writes with non-zero values for the device ID.
1289
1290	  If unsure, say Y.
1291
1292endmenu # "ARM errata workarounds via the alternatives framework"
1293
1294choice
1295	prompt "Page size"
1296	default ARM64_4K_PAGES
1297	help
1298	  Page size (translation granule) configuration.
1299
1300config ARM64_4K_PAGES
1301	bool "4KB"
1302	help
1303	  This feature enables 4KB pages support.
1304
1305config ARM64_16K_PAGES
1306	bool "16KB"
1307	help
1308	  The system will use 16KB pages support. AArch32 emulation
1309	  requires applications compiled with 16K (or a multiple of 16K)
1310	  aligned segments.
1311
1312config ARM64_64K_PAGES
1313	bool "64KB"
1314	help
1315	  This feature enables 64KB pages support (4KB by default)
1316	  allowing only two levels of page tables and faster TLB
1317	  look-up. AArch32 emulation requires applications compiled
1318	  with 64K aligned segments.
1319
1320endchoice
1321
1322choice
1323	prompt "Virtual address space size"
1324	default ARM64_VA_BITS_39 if ARM64_4K_PAGES
1325	default ARM64_VA_BITS_47 if ARM64_16K_PAGES
1326	default ARM64_VA_BITS_42 if ARM64_64K_PAGES
1327	help
1328	  Allows choosing one of multiple possible virtual address
1329	  space sizes. The level of translation table is determined by
1330	  a combination of page size and virtual address space size.
1331
1332config ARM64_VA_BITS_36
1333	bool "36-bit" if EXPERT
1334	depends on ARM64_16K_PAGES
1335
1336config ARM64_VA_BITS_39
1337	bool "39-bit"
1338	depends on ARM64_4K_PAGES
1339
1340config ARM64_VA_BITS_42
1341	bool "42-bit"
1342	depends on ARM64_64K_PAGES
1343
1344config ARM64_VA_BITS_47
1345	bool "47-bit"
1346	depends on ARM64_16K_PAGES
1347
1348config ARM64_VA_BITS_48
1349	bool "48-bit"
1350
1351config ARM64_VA_BITS_52
1352	bool "52-bit"
1353	depends on ARM64_64K_PAGES && (ARM64_PAN || !ARM64_SW_TTBR0_PAN)
1354	help
1355	  Enable 52-bit virtual addressing for userspace when explicitly
1356	  requested via a hint to mmap(). The kernel will also use 52-bit
1357	  virtual addresses for its own mappings (provided HW support for
1358	  this feature is available, otherwise it reverts to 48-bit).
1359
1360	  NOTE: Enabling 52-bit virtual addressing in conjunction with
1361	  ARMv8.3 Pointer Authentication will result in the PAC being
1362	  reduced from 7 bits to 3 bits, which may have a significant
1363	  impact on its susceptibility to brute-force attacks.
1364
1365	  If unsure, select 48-bit virtual addressing instead.
1366
1367endchoice
1368
1369config ARM64_FORCE_52BIT
1370	bool "Force 52-bit virtual addresses for userspace"
1371	depends on ARM64_VA_BITS_52 && EXPERT
1372	help
1373	  For systems with 52-bit userspace VAs enabled, the kernel will attempt
1374	  to maintain compatibility with older software by providing 48-bit VAs
1375	  unless a hint is supplied to mmap.
1376
1377	  This configuration option disables the 48-bit compatibility logic, and
1378	  forces all userspace addresses to be 52-bit on HW that supports it. One
1379	  should only enable this configuration option for stress testing userspace
1380	  memory management code. If unsure say N here.
1381
1382config ARM64_VA_BITS
1383	int
1384	default 36 if ARM64_VA_BITS_36
1385	default 39 if ARM64_VA_BITS_39
1386	default 42 if ARM64_VA_BITS_42
1387	default 47 if ARM64_VA_BITS_47
1388	default 48 if ARM64_VA_BITS_48
1389	default 52 if ARM64_VA_BITS_52
1390
1391choice
1392	prompt "Physical address space size"
1393	default ARM64_PA_BITS_48
1394	help
1395	  Choose the maximum physical address range that the kernel will
1396	  support.
1397
1398config ARM64_PA_BITS_48
1399	bool "48-bit"
1400
1401config ARM64_PA_BITS_52
1402	bool "52-bit (ARMv8.2)"
1403	depends on ARM64_64K_PAGES
1404	depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
1405	help
1406	  Enable support for a 52-bit physical address space, introduced as
1407	  part of the ARMv8.2-LPA extension.
1408
1409	  With this enabled, the kernel will also continue to work on CPUs that
1410	  do not support ARMv8.2-LPA, but with some added memory overhead (and
1411	  minor performance overhead).
1412
1413endchoice
1414
1415config ARM64_PA_BITS
1416	int
1417	default 48 if ARM64_PA_BITS_48
1418	default 52 if ARM64_PA_BITS_52
1419
1420choice
1421	prompt "Endianness"
1422	default CPU_LITTLE_ENDIAN
1423	help
1424	  Select the endianness of data accesses performed by the CPU. Userspace
1425	  applications will need to be compiled and linked for the endianness
1426	  that is selected here.
1427
1428config CPU_BIG_ENDIAN
1429	bool "Build big-endian kernel"
1430	depends on !LD_IS_LLD || LLD_VERSION >= 130000
1431	# https://github.com/llvm/llvm-project/commit/1379b150991f70a5782e9a143c2ba5308da1161c
1432	depends on AS_IS_GNU || AS_VERSION >= 150000
1433	help
1434	  Say Y if you plan on running a kernel with a big-endian userspace.
1435
1436config CPU_LITTLE_ENDIAN
1437	bool "Build little-endian kernel"
1438	help
1439	  Say Y if you plan on running a kernel with a little-endian userspace.
1440	  This is usually the case for distributions targeting arm64.
1441
1442endchoice
1443
1444config SCHED_MC
1445	bool "Multi-core scheduler support"
1446	help
1447	  Multi-core scheduler support improves the CPU scheduler's decision
1448	  making when dealing with multi-core CPU chips at a cost of slightly
1449	  increased overhead in some places. If unsure say N here.
1450
1451config SCHED_CLUSTER
1452	bool "Cluster scheduler support"
1453	help
1454	  Cluster scheduler support improves the CPU scheduler's decision
1455	  making when dealing with machines that have clusters of CPUs.
1456	  Cluster usually means a couple of CPUs which are placed closely
1457	  by sharing mid-level caches, last-level cache tags or internal
1458	  busses.
1459
1460config SCHED_SMT
1461	bool "SMT scheduler support"
1462	help
1463	  Improves the CPU scheduler's decision making when dealing with
1464	  MultiThreading at a cost of slightly increased overhead in some
1465	  places. If unsure say N here.
1466
1467config NR_CPUS
1468	int "Maximum number of CPUs (2-4096)"
1469	range 2 4096
1470	default "256"
1471
1472config HOTPLUG_CPU
1473	bool "Support for hot-pluggable CPUs"
1474	select GENERIC_IRQ_MIGRATION
1475	help
1476	  Say Y here to experiment with turning CPUs off and on.  CPUs
1477	  can be controlled through /sys/devices/system/cpu.
1478
1479# Common NUMA Features
1480config NUMA
1481	bool "NUMA Memory Allocation and Scheduler Support"
1482	select GENERIC_ARCH_NUMA
1483	select ACPI_NUMA if ACPI
1484	select OF_NUMA
1485	select HAVE_SETUP_PER_CPU_AREA
1486	select NEED_PER_CPU_EMBED_FIRST_CHUNK
1487	select NEED_PER_CPU_PAGE_FIRST_CHUNK
1488	select USE_PERCPU_NUMA_NODE_ID
1489	help
1490	  Enable NUMA (Non-Uniform Memory Access) support.
1491
1492	  The kernel will try to allocate memory used by a CPU on the
1493	  local memory of the CPU and add some more
1494	  NUMA awareness to the kernel.
1495
1496config NODES_SHIFT
1497	int "Maximum NUMA Nodes (as a power of 2)"
1498	range 1 10
1499	default "4"
1500	depends on NUMA
1501	help
1502	  Specify the maximum number of NUMA Nodes available on the target
1503	  system.  Increases memory reserved to accommodate various tables.
1504
1505source "kernel/Kconfig.hz"
1506
1507config ARCH_SPARSEMEM_ENABLE
1508	def_bool y
1509	select SPARSEMEM_VMEMMAP_ENABLE
1510	select SPARSEMEM_VMEMMAP
1511
1512config HW_PERF_EVENTS
1513	def_bool y
1514	depends on ARM_PMU
1515
1516# Supported by clang >= 7.0 or GCC >= 12.0.0
1517config CC_HAVE_SHADOW_CALL_STACK
1518	def_bool $(cc-option, -fsanitize=shadow-call-stack -ffixed-x18)
1519
1520config PARAVIRT
1521	bool "Enable paravirtualization code"
1522	help
1523	  This changes the kernel so it can modify itself when it is run
1524	  under a hypervisor, potentially improving performance significantly
1525	  over full virtualization.
1526
1527config PARAVIRT_TIME_ACCOUNTING
1528	bool "Paravirtual steal time accounting"
1529	select PARAVIRT
1530	help
1531	  Select this option to enable fine granularity task steal time
1532	  accounting. Time spent executing other tasks in parallel with
1533	  the current vCPU is discounted from the vCPU power. To account for
1534	  that, there can be a small performance impact.
1535
1536	  If in doubt, say N here.
1537
1538config ARCH_SUPPORTS_KEXEC
1539	def_bool PM_SLEEP_SMP
1540
1541config ARCH_SUPPORTS_KEXEC_FILE
1542	def_bool y
1543
1544config ARCH_SELECTS_KEXEC_FILE
1545	def_bool y
1546	depends on KEXEC_FILE
1547	select HAVE_IMA_KEXEC if IMA
1548
1549config ARCH_SUPPORTS_KEXEC_SIG
1550	def_bool y
1551
1552config ARCH_SUPPORTS_KEXEC_IMAGE_VERIFY_SIG
1553	def_bool y
1554
1555config ARCH_DEFAULT_KEXEC_IMAGE_VERIFY_SIG
1556	def_bool y
1557
1558config ARCH_SUPPORTS_CRASH_DUMP
1559	def_bool y
1560
1561config TRANS_TABLE
1562	def_bool y
1563	depends on HIBERNATION || KEXEC_CORE
1564
1565config XEN_DOM0
1566	def_bool y
1567	depends on XEN
1568
1569config XEN
1570	bool "Xen guest support on ARM64"
1571	depends on ARM64 && OF
1572	select SWIOTLB_XEN
1573	select PARAVIRT
1574	help
1575	  Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64.
1576
1577# include/linux/mmzone.h requires the following to be true:
1578#
1579#   MAX_ORDER + PAGE_SHIFT <= SECTION_SIZE_BITS
1580#
1581# so the maximum value of MAX_ORDER is SECTION_SIZE_BITS - PAGE_SHIFT:
1582#
1583#     | SECTION_SIZE_BITS |  PAGE_SHIFT  |  max MAX_ORDER  |  default MAX_ORDER |
1584# ----+-------------------+--------------+-----------------+--------------------+
1585# 4K  |       27          |      12      |       15        |         10         |
1586# 16K |       27          |      14      |       13        |         11         |
1587# 64K |       29          |      16      |       13        |         13         |
1588config ARCH_FORCE_MAX_ORDER
1589	int
1590	default "13" if ARM64_64K_PAGES
1591	default "11" if ARM64_16K_PAGES
1592	default "10"
1593	help
1594	  The kernel page allocator limits the size of maximal physically
1595	  contiguous allocations. The limit is called MAX_ORDER and it
1596	  defines the maximal power of two of number of pages that can be
1597	  allocated as a single contiguous block. This option allows
1598	  overriding the default setting when ability to allocate very
1599	  large blocks of physically contiguous memory is required.
1600
1601	  The maximal size of allocation cannot exceed the size of the
1602	  section, so the value of MAX_ORDER should satisfy
1603
1604	    MAX_ORDER + PAGE_SHIFT <= SECTION_SIZE_BITS
1605
1606	  Don't change if unsure.
1607
1608config UNMAP_KERNEL_AT_EL0
1609	bool "Unmap kernel when running in userspace (aka \"KAISER\")" if EXPERT
1610	default y
1611	help
1612	  Speculation attacks against some high-performance processors can
1613	  be used to bypass MMU permission checks and leak kernel data to
1614	  userspace. This can be defended against by unmapping the kernel
1615	  when running in userspace, mapping it back in on exception entry
1616	  via a trampoline page in the vector table.
1617
1618	  If unsure, say Y.
1619
1620config MITIGATE_SPECTRE_BRANCH_HISTORY
1621	bool "Mitigate Spectre style attacks against branch history" if EXPERT
1622	default y
1623	help
1624	  Speculation attacks against some high-performance processors can
1625	  make use of branch history to influence future speculation.
1626	  When taking an exception from user-space, a sequence of branches
1627	  or a firmware call overwrites the branch history.
1628
1629config RODATA_FULL_DEFAULT_ENABLED
1630	bool "Apply r/o permissions of VM areas also to their linear aliases"
1631	default y
1632	help
1633	  Apply read-only attributes of VM areas to the linear alias of
1634	  the backing pages as well. This prevents code or read-only data
1635	  from being modified (inadvertently or intentionally) via another
1636	  mapping of the same memory page. This additional enhancement can
1637	  be turned off at runtime by passing rodata=[off|on] (and turned on
1638	  with rodata=full if this option is set to 'n')
1639
1640	  This requires the linear region to be mapped down to pages,
1641	  which may adversely affect performance in some cases.
1642
1643config ARM64_SW_TTBR0_PAN
1644	bool "Emulate Privileged Access Never using TTBR0_EL1 switching"
1645	help
1646	  Enabling this option prevents the kernel from accessing
1647	  user-space memory directly by pointing TTBR0_EL1 to a reserved
1648	  zeroed area and reserved ASID. The user access routines
1649	  restore the valid TTBR0_EL1 temporarily.
1650
1651config ARM64_TAGGED_ADDR_ABI
1652	bool "Enable the tagged user addresses syscall ABI"
1653	default y
1654	help
1655	  When this option is enabled, user applications can opt in to a
1656	  relaxed ABI via prctl() allowing tagged addresses to be passed
1657	  to system calls as pointer arguments. For details, see
1658	  Documentation/arch/arm64/tagged-address-abi.rst.
1659
1660menuconfig COMPAT
1661	bool "Kernel support for 32-bit EL0"
1662	depends on ARM64_4K_PAGES || EXPERT
1663	select HAVE_UID16
1664	select OLD_SIGSUSPEND3
1665	select COMPAT_OLD_SIGACTION
1666	help
1667	  This option enables support for a 32-bit EL0 running under a 64-bit
1668	  kernel at EL1. AArch32-specific components such as system calls,
1669	  the user helper functions, VFP support and the ptrace interface are
1670	  handled appropriately by the kernel.
1671
1672	  If you use a page size other than 4KB (i.e, 16KB or 64KB), please be aware
1673	  that you will only be able to execute AArch32 binaries that were compiled
1674	  with page size aligned segments.
1675
1676	  If you want to execute 32-bit userspace applications, say Y.
1677
1678if COMPAT
1679
1680config KUSER_HELPERS
1681	bool "Enable kuser helpers page for 32-bit applications"
1682	default y
1683	help
1684	  Warning: disabling this option may break 32-bit user programs.
1685
1686	  Provide kuser helpers to compat tasks. The kernel provides
1687	  helper code to userspace in read only form at a fixed location
1688	  to allow userspace to be independent of the CPU type fitted to
1689	  the system. This permits binaries to be run on ARMv4 through
1690	  to ARMv8 without modification.
1691
1692	  See Documentation/arch/arm/kernel_user_helpers.rst for details.
1693
1694	  However, the fixed address nature of these helpers can be used
1695	  by ROP (return orientated programming) authors when creating
1696	  exploits.
1697
1698	  If all of the binaries and libraries which run on your platform
1699	  are built specifically for your platform, and make no use of
1700	  these helpers, then you can turn this option off to hinder
1701	  such exploits. However, in that case, if a binary or library
1702	  relying on those helpers is run, it will not function correctly.
1703
1704	  Say N here only if you are absolutely certain that you do not
1705	  need these helpers; otherwise, the safe option is to say Y.
1706
1707config COMPAT_VDSO
1708	bool "Enable vDSO for 32-bit applications"
1709	depends on !CPU_BIG_ENDIAN
1710	depends on (CC_IS_CLANG && LD_IS_LLD) || "$(CROSS_COMPILE_COMPAT)" != ""
1711	select GENERIC_COMPAT_VDSO
1712	default y
1713	help
1714	  Place in the process address space of 32-bit applications an
1715	  ELF shared object providing fast implementations of gettimeofday
1716	  and clock_gettime.
1717
1718	  You must have a 32-bit build of glibc 2.22 or later for programs
1719	  to seamlessly take advantage of this.
1720
1721config THUMB2_COMPAT_VDSO
1722	bool "Compile the 32-bit vDSO for Thumb-2 mode" if EXPERT
1723	depends on COMPAT_VDSO
1724	default y
1725	help
1726	  Compile the compat vDSO with '-mthumb -fomit-frame-pointer' if y,
1727	  otherwise with '-marm'.
1728
1729config COMPAT_ALIGNMENT_FIXUPS
1730	bool "Fix up misaligned multi-word loads and stores in user space"
1731
1732menuconfig ARMV8_DEPRECATED
1733	bool "Emulate deprecated/obsolete ARMv8 instructions"
1734	depends on SYSCTL
1735	help
1736	  Legacy software support may require certain instructions
1737	  that have been deprecated or obsoleted in the architecture.
1738
1739	  Enable this config to enable selective emulation of these
1740	  features.
1741
1742	  If unsure, say Y
1743
1744if ARMV8_DEPRECATED
1745
1746config SWP_EMULATION
1747	bool "Emulate SWP/SWPB instructions"
1748	help
1749	  ARMv8 obsoletes the use of A32 SWP/SWPB instructions such that
1750	  they are always undefined. Say Y here to enable software
1751	  emulation of these instructions for userspace using LDXR/STXR.
1752	  This feature can be controlled at runtime with the abi.swp
1753	  sysctl which is disabled by default.
1754
1755	  In some older versions of glibc [<=2.8] SWP is used during futex
1756	  trylock() operations with the assumption that the code will not
1757	  be preempted. This invalid assumption may be more likely to fail
1758	  with SWP emulation enabled, leading to deadlock of the user
1759	  application.
1760
1761	  NOTE: when accessing uncached shared regions, LDXR/STXR rely
1762	  on an external transaction monitoring block called a global
1763	  monitor to maintain update atomicity. If your system does not
1764	  implement a global monitor, this option can cause programs that
1765	  perform SWP operations to uncached memory to deadlock.
1766
1767	  If unsure, say Y
1768
1769config CP15_BARRIER_EMULATION
1770	bool "Emulate CP15 Barrier instructions"
1771	help
1772	  The CP15 barrier instructions - CP15ISB, CP15DSB, and
1773	  CP15DMB - are deprecated in ARMv8 (and ARMv7). It is
1774	  strongly recommended to use the ISB, DSB, and DMB
1775	  instructions instead.
1776
1777	  Say Y here to enable software emulation of these
1778	  instructions for AArch32 userspace code. When this option is
1779	  enabled, CP15 barrier usage is traced which can help
1780	  identify software that needs updating. This feature can be
1781	  controlled at runtime with the abi.cp15_barrier sysctl.
1782
1783	  If unsure, say Y
1784
1785config SETEND_EMULATION
1786	bool "Emulate SETEND instruction"
1787	help
1788	  The SETEND instruction alters the data-endianness of the
1789	  AArch32 EL0, and is deprecated in ARMv8.
1790
1791	  Say Y here to enable software emulation of the instruction
1792	  for AArch32 userspace code. This feature can be controlled
1793	  at runtime with the abi.setend sysctl.
1794
1795	  Note: All the cpus on the system must have mixed endian support at EL0
1796	  for this feature to be enabled. If a new CPU - which doesn't support mixed
1797	  endian - is hotplugged in after this feature has been enabled, there could
1798	  be unexpected results in the applications.
1799
1800	  If unsure, say Y
1801endif # ARMV8_DEPRECATED
1802
1803endif # COMPAT
1804
1805menu "ARMv8.1 architectural features"
1806
1807config ARM64_HW_AFDBM
1808	bool "Support for hardware updates of the Access and Dirty page flags"
1809	default y
1810	help
1811	  The ARMv8.1 architecture extensions introduce support for
1812	  hardware updates of the access and dirty information in page
1813	  table entries. When enabled in TCR_EL1 (HA and HD bits) on
1814	  capable processors, accesses to pages with PTE_AF cleared will
1815	  set this bit instead of raising an access flag fault.
1816	  Similarly, writes to read-only pages with the DBM bit set will
1817	  clear the read-only bit (AP[2]) instead of raising a
1818	  permission fault.
1819
1820	  Kernels built with this configuration option enabled continue
1821	  to work on pre-ARMv8.1 hardware and the performance impact is
1822	  minimal. If unsure, say Y.
1823
1824config ARM64_PAN
1825	bool "Enable support for Privileged Access Never (PAN)"
1826	default y
1827	help
1828	  Privileged Access Never (PAN; part of the ARMv8.1 Extensions)
1829	  prevents the kernel or hypervisor from accessing user-space (EL0)
1830	  memory directly.
1831
1832	  Choosing this option will cause any unprotected (not using
1833	  copy_to_user et al) memory access to fail with a permission fault.
1834
1835	  The feature is detected at runtime, and will remain as a 'nop'
1836	  instruction if the cpu does not implement the feature.
1837
1838config AS_HAS_LSE_ATOMICS
1839	def_bool $(as-instr,.arch_extension lse)
1840
1841config ARM64_LSE_ATOMICS
1842	bool
1843	default ARM64_USE_LSE_ATOMICS
1844	depends on AS_HAS_LSE_ATOMICS
1845
1846config ARM64_USE_LSE_ATOMICS
1847	bool "Atomic instructions"
1848	default y
1849	help
1850	  As part of the Large System Extensions, ARMv8.1 introduces new
1851	  atomic instructions that are designed specifically to scale in
1852	  very large systems.
1853
1854	  Say Y here to make use of these instructions for the in-kernel
1855	  atomic routines. This incurs a small overhead on CPUs that do
1856	  not support these instructions and requires the kernel to be
1857	  built with binutils >= 2.25 in order for the new instructions
1858	  to be used.
1859
1860endmenu # "ARMv8.1 architectural features"
1861
1862menu "ARMv8.2 architectural features"
1863
1864config AS_HAS_ARMV8_2
1865	def_bool $(cc-option,-Wa$(comma)-march=armv8.2-a)
1866
1867config AS_HAS_SHA3
1868	def_bool $(as-instr,.arch armv8.2-a+sha3)
1869
1870config ARM64_PMEM
1871	bool "Enable support for persistent memory"
1872	select ARCH_HAS_PMEM_API
1873	select ARCH_HAS_UACCESS_FLUSHCACHE
1874	help
1875	  Say Y to enable support for the persistent memory API based on the
1876	  ARMv8.2 DCPoP feature.
1877
1878	  The feature is detected at runtime, and the kernel will use DC CVAC
1879	  operations if DC CVAP is not supported (following the behaviour of
1880	  DC CVAP itself if the system does not define a point of persistence).
1881
1882config ARM64_RAS_EXTN
1883	bool "Enable support for RAS CPU Extensions"
1884	default y
1885	help
1886	  CPUs that support the Reliability, Availability and Serviceability
1887	  (RAS) Extensions, part of ARMv8.2 are able to track faults and
1888	  errors, classify them and report them to software.
1889
1890	  On CPUs with these extensions system software can use additional
1891	  barriers to determine if faults are pending and read the
1892	  classification from a new set of registers.
1893
1894	  Selecting this feature will allow the kernel to use these barriers
1895	  and access the new registers if the system supports the extension.
1896	  Platform RAS features may additionally depend on firmware support.
1897
1898config ARM64_CNP
1899	bool "Enable support for Common Not Private (CNP) translations"
1900	default y
1901	depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
1902	help
1903	  Common Not Private (CNP) allows translation table entries to
1904	  be shared between different PEs in the same inner shareable
1905	  domain, so the hardware can use this fact to optimise the
1906	  caching of such entries in the TLB.
1907
1908	  Selecting this option allows the CNP feature to be detected
1909	  at runtime, and does not affect PEs that do not implement
1910	  this feature.
1911
1912endmenu # "ARMv8.2 architectural features"
1913
1914menu "ARMv8.3 architectural features"
1915
1916config ARM64_PTR_AUTH
1917	bool "Enable support for pointer authentication"
1918	default y
1919	help
1920	  Pointer authentication (part of the ARMv8.3 Extensions) provides
1921	  instructions for signing and authenticating pointers against secret
1922	  keys, which can be used to mitigate Return Oriented Programming (ROP)
1923	  and other attacks.
1924
1925	  This option enables these instructions at EL0 (i.e. for userspace).
1926	  Choosing this option will cause the kernel to initialise secret keys
1927	  for each process at exec() time, with these keys being
1928	  context-switched along with the process.
1929
1930	  The feature is detected at runtime. If the feature is not present in
1931	  hardware it will not be advertised to userspace/KVM guest nor will it
1932	  be enabled.
1933
1934	  If the feature is present on the boot CPU but not on a late CPU, then
1935	  the late CPU will be parked. Also, if the boot CPU does not have
1936	  address auth and the late CPU has then the late CPU will still boot
1937	  but with the feature disabled. On such a system, this option should
1938	  not be selected.
1939
1940config ARM64_PTR_AUTH_KERNEL
1941	bool "Use pointer authentication for kernel"
1942	default y
1943	depends on ARM64_PTR_AUTH
1944	depends on (CC_HAS_SIGN_RETURN_ADDRESS || CC_HAS_BRANCH_PROT_PAC_RET) && AS_HAS_ARMV8_3
1945	# Modern compilers insert a .note.gnu.property section note for PAC
1946	# which is only understood by binutils starting with version 2.33.1.
1947	depends on LD_IS_LLD || LD_VERSION >= 23301 || (CC_IS_GCC && GCC_VERSION < 90100)
1948	depends on !CC_IS_CLANG || AS_HAS_CFI_NEGATE_RA_STATE
1949	depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_ARGS)
1950	help
1951	  If the compiler supports the -mbranch-protection or
1952	  -msign-return-address flag (e.g. GCC 7 or later), then this option
1953	  will cause the kernel itself to be compiled with return address
1954	  protection. In this case, and if the target hardware is known to
1955	  support pointer authentication, then CONFIG_STACKPROTECTOR can be
1956	  disabled with minimal loss of protection.
1957
1958	  This feature works with FUNCTION_GRAPH_TRACER option only if
1959	  DYNAMIC_FTRACE_WITH_ARGS is enabled.
1960
1961config CC_HAS_BRANCH_PROT_PAC_RET
1962	# GCC 9 or later, clang 8 or later
1963	def_bool $(cc-option,-mbranch-protection=pac-ret+leaf)
1964
1965config CC_HAS_SIGN_RETURN_ADDRESS
1966	# GCC 7, 8
1967	def_bool $(cc-option,-msign-return-address=all)
1968
1969config AS_HAS_ARMV8_3
1970	def_bool $(cc-option,-Wa$(comma)-march=armv8.3-a)
1971
1972config AS_HAS_CFI_NEGATE_RA_STATE
1973	def_bool $(as-instr,.cfi_startproc\n.cfi_negate_ra_state\n.cfi_endproc\n)
1974
1975config AS_HAS_LDAPR
1976	def_bool $(as-instr,.arch_extension rcpc)
1977
1978endmenu # "ARMv8.3 architectural features"
1979
1980menu "ARMv8.4 architectural features"
1981
1982config ARM64_AMU_EXTN
1983	bool "Enable support for the Activity Monitors Unit CPU extension"
1984	default y
1985	help
1986	  The activity monitors extension is an optional extension introduced
1987	  by the ARMv8.4 CPU architecture. This enables support for version 1
1988	  of the activity monitors architecture, AMUv1.
1989
1990	  To enable the use of this extension on CPUs that implement it, say Y.
1991
1992	  Note that for architectural reasons, firmware _must_ implement AMU
1993	  support when running on CPUs that present the activity monitors
1994	  extension. The required support is present in:
1995	    * Version 1.5 and later of the ARM Trusted Firmware
1996
1997	  For kernels that have this configuration enabled but boot with broken
1998	  firmware, you may need to say N here until the firmware is fixed.
1999	  Otherwise you may experience firmware panics or lockups when
2000	  accessing the counter registers. Even if you are not observing these
2001	  symptoms, the values returned by the register reads might not
2002	  correctly reflect reality. Most commonly, the value read will be 0,
2003	  indicating that the counter is not enabled.
2004
2005config AS_HAS_ARMV8_4
2006	def_bool $(cc-option,-Wa$(comma)-march=armv8.4-a)
2007
2008config ARM64_TLB_RANGE
2009	bool "Enable support for tlbi range feature"
2010	default y
2011	depends on AS_HAS_ARMV8_4
2012	help
2013	  ARMv8.4-TLBI provides TLBI invalidation instruction that apply to a
2014	  range of input addresses.
2015
2016	  The feature introduces new assembly instructions, and they were
2017	  support when binutils >= 2.30.
2018
2019endmenu # "ARMv8.4 architectural features"
2020
2021menu "ARMv8.5 architectural features"
2022
2023config AS_HAS_ARMV8_5
2024	def_bool $(cc-option,-Wa$(comma)-march=armv8.5-a)
2025
2026config ARM64_BTI
2027	bool "Branch Target Identification support"
2028	default y
2029	help
2030	  Branch Target Identification (part of the ARMv8.5 Extensions)
2031	  provides a mechanism to limit the set of locations to which computed
2032	  branch instructions such as BR or BLR can jump.
2033
2034	  To make use of BTI on CPUs that support it, say Y.
2035
2036	  BTI is intended to provide complementary protection to other control
2037	  flow integrity protection mechanisms, such as the Pointer
2038	  authentication mechanism provided as part of the ARMv8.3 Extensions.
2039	  For this reason, it does not make sense to enable this option without
2040	  also enabling support for pointer authentication.  Thus, when
2041	  enabling this option you should also select ARM64_PTR_AUTH=y.
2042
2043	  Userspace binaries must also be specifically compiled to make use of
2044	  this mechanism.  If you say N here or the hardware does not support
2045	  BTI, such binaries can still run, but you get no additional
2046	  enforcement of branch destinations.
2047
2048config ARM64_BTI_KERNEL
2049	bool "Use Branch Target Identification for kernel"
2050	default y
2051	depends on ARM64_BTI
2052	depends on ARM64_PTR_AUTH_KERNEL
2053	depends on CC_HAS_BRANCH_PROT_PAC_RET_BTI
2054	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94697
2055	depends on !CC_IS_GCC || GCC_VERSION >= 100100
2056	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106671
2057	depends on !CC_IS_GCC
2058	# https://github.com/llvm/llvm-project/commit/a88c722e687e6780dcd6a58718350dc76fcc4cc9
2059	depends on !CC_IS_CLANG || CLANG_VERSION >= 120000
2060	depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_ARGS)
2061	help
2062	  Build the kernel with Branch Target Identification annotations
2063	  and enable enforcement of this for kernel code. When this option
2064	  is enabled and the system supports BTI all kernel code including
2065	  modular code must have BTI enabled.
2066
2067config CC_HAS_BRANCH_PROT_PAC_RET_BTI
2068	# GCC 9 or later, clang 8 or later
2069	def_bool $(cc-option,-mbranch-protection=pac-ret+leaf+bti)
2070
2071config ARM64_E0PD
2072	bool "Enable support for E0PD"
2073	default y
2074	help
2075	  E0PD (part of the ARMv8.5 extensions) allows us to ensure
2076	  that EL0 accesses made via TTBR1 always fault in constant time,
2077	  providing similar benefits to KASLR as those provided by KPTI, but
2078	  with lower overhead and without disrupting legitimate access to
2079	  kernel memory such as SPE.
2080
2081	  This option enables E0PD for TTBR1 where available.
2082
2083config ARM64_AS_HAS_MTE
2084	# Initial support for MTE went in binutils 2.32.0, checked with
2085	# ".arch armv8.5-a+memtag" below. However, this was incomplete
2086	# as a late addition to the final architecture spec (LDGM/STGM)
2087	# is only supported in the newer 2.32.x and 2.33 binutils
2088	# versions, hence the extra "stgm" instruction check below.
2089	def_bool $(as-instr,.arch armv8.5-a+memtag\nstgm xzr$(comma)[x0])
2090
2091config ARM64_MTE
2092	bool "Memory Tagging Extension support"
2093	default y
2094	depends on ARM64_AS_HAS_MTE && ARM64_TAGGED_ADDR_ABI
2095	depends on AS_HAS_ARMV8_5
2096	depends on AS_HAS_LSE_ATOMICS
2097	# Required for tag checking in the uaccess routines
2098	depends on ARM64_PAN
2099	select ARCH_HAS_SUBPAGE_FAULTS
2100	select ARCH_USES_HIGH_VMA_FLAGS
2101	select ARCH_USES_PG_ARCH_X
2102	help
2103	  Memory Tagging (part of the ARMv8.5 Extensions) provides
2104	  architectural support for run-time, always-on detection of
2105	  various classes of memory error to aid with software debugging
2106	  to eliminate vulnerabilities arising from memory-unsafe
2107	  languages.
2108
2109	  This option enables the support for the Memory Tagging
2110	  Extension at EL0 (i.e. for userspace).
2111
2112	  Selecting this option allows the feature to be detected at
2113	  runtime. Any secondary CPU not implementing this feature will
2114	  not be allowed a late bring-up.
2115
2116	  Userspace binaries that want to use this feature must
2117	  explicitly opt in. The mechanism for the userspace is
2118	  described in:
2119
2120	  Documentation/arch/arm64/memory-tagging-extension.rst.
2121
2122endmenu # "ARMv8.5 architectural features"
2123
2124menu "ARMv8.7 architectural features"
2125
2126config ARM64_EPAN
2127	bool "Enable support for Enhanced Privileged Access Never (EPAN)"
2128	default y
2129	depends on ARM64_PAN
2130	help
2131	  Enhanced Privileged Access Never (EPAN) allows Privileged
2132	  Access Never to be used with Execute-only mappings.
2133
2134	  The feature is detected at runtime, and will remain disabled
2135	  if the cpu does not implement the feature.
2136endmenu # "ARMv8.7 architectural features"
2137
2138config ARM64_SVE
2139	bool "ARM Scalable Vector Extension support"
2140	default y
2141	help
2142	  The Scalable Vector Extension (SVE) is an extension to the AArch64
2143	  execution state which complements and extends the SIMD functionality
2144	  of the base architecture to support much larger vectors and to enable
2145	  additional vectorisation opportunities.
2146
2147	  To enable use of this extension on CPUs that implement it, say Y.
2148
2149	  On CPUs that support the SVE2 extensions, this option will enable
2150	  those too.
2151
2152	  Note that for architectural reasons, firmware _must_ implement SVE
2153	  support when running on SVE capable hardware.  The required support
2154	  is present in:
2155
2156	    * version 1.5 and later of the ARM Trusted Firmware
2157	    * the AArch64 boot wrapper since commit 5e1261e08abf
2158	      ("bootwrapper: SVE: Enable SVE for EL2 and below").
2159
2160	  For other firmware implementations, consult the firmware documentation
2161	  or vendor.
2162
2163	  If you need the kernel to boot on SVE-capable hardware with broken
2164	  firmware, you may need to say N here until you get your firmware
2165	  fixed.  Otherwise, you may experience firmware panics or lockups when
2166	  booting the kernel.  If unsure and you are not observing these
2167	  symptoms, you should assume that it is safe to say Y.
2168
2169config ARM64_SME
2170	bool "ARM Scalable Matrix Extension support"
2171	default y
2172	depends on ARM64_SVE
2173	help
2174	  The Scalable Matrix Extension (SME) is an extension to the AArch64
2175	  execution state which utilises a substantial subset of the SVE
2176	  instruction set, together with the addition of new architectural
2177	  register state capable of holding two dimensional matrix tiles to
2178	  enable various matrix operations.
2179
2180config ARM64_PSEUDO_NMI
2181	bool "Support for NMI-like interrupts"
2182	select ARM_GIC_V3
2183	help
2184	  Adds support for mimicking Non-Maskable Interrupts through the use of
2185	  GIC interrupt priority. This support requires version 3 or later of
2186	  ARM GIC.
2187
2188	  This high priority configuration for interrupts needs to be
2189	  explicitly enabled by setting the kernel parameter
2190	  "irqchip.gicv3_pseudo_nmi" to 1.
2191
2192	  If unsure, say N
2193
2194if ARM64_PSEUDO_NMI
2195config ARM64_DEBUG_PRIORITY_MASKING
2196	bool "Debug interrupt priority masking"
2197	help
2198	  This adds runtime checks to functions enabling/disabling
2199	  interrupts when using priority masking. The additional checks verify
2200	  the validity of ICC_PMR_EL1 when calling concerned functions.
2201
2202	  If unsure, say N
2203endif # ARM64_PSEUDO_NMI
2204
2205config RELOCATABLE
2206	bool "Build a relocatable kernel image" if EXPERT
2207	select ARCH_HAS_RELR
2208	default y
2209	help
2210	  This builds the kernel as a Position Independent Executable (PIE),
2211	  which retains all relocation metadata required to relocate the
2212	  kernel binary at runtime to a different virtual address than the
2213	  address it was linked at.
2214	  Since AArch64 uses the RELA relocation format, this requires a
2215	  relocation pass at runtime even if the kernel is loaded at the
2216	  same address it was linked at.
2217
2218config RANDOMIZE_BASE
2219	bool "Randomize the address of the kernel image"
2220	select RELOCATABLE
2221	help
2222	  Randomizes the virtual address at which the kernel image is
2223	  loaded, as a security feature that deters exploit attempts
2224	  relying on knowledge of the location of kernel internals.
2225
2226	  It is the bootloader's job to provide entropy, by passing a
2227	  random u64 value in /chosen/kaslr-seed at kernel entry.
2228
2229	  When booting via the UEFI stub, it will invoke the firmware's
2230	  EFI_RNG_PROTOCOL implementation (if available) to supply entropy
2231	  to the kernel proper. In addition, it will randomise the physical
2232	  location of the kernel Image as well.
2233
2234	  If unsure, say N.
2235
2236config RANDOMIZE_MODULE_REGION_FULL
2237	bool "Randomize the module region over a 2 GB range"
2238	depends on RANDOMIZE_BASE
2239	default y
2240	help
2241	  Randomizes the location of the module region inside a 2 GB window
2242	  covering the core kernel. This way, it is less likely for modules
2243	  to leak information about the location of core kernel data structures
2244	  but it does imply that function calls between modules and the core
2245	  kernel will need to be resolved via veneers in the module PLT.
2246
2247	  When this option is not set, the module region will be randomized over
2248	  a limited range that contains the [_stext, _etext] interval of the
2249	  core kernel, so branch relocations are almost always in range unless
2250	  the region is exhausted. In this particular case of region
2251	  exhaustion, modules might be able to fall back to a larger 2GB area.
2252
2253config CC_HAVE_STACKPROTECTOR_SYSREG
2254	def_bool $(cc-option,-mstack-protector-guard=sysreg -mstack-protector-guard-reg=sp_el0 -mstack-protector-guard-offset=0)
2255
2256config STACKPROTECTOR_PER_TASK
2257	def_bool y
2258	depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_SYSREG
2259
2260config UNWIND_PATCH_PAC_INTO_SCS
2261	bool "Enable shadow call stack dynamically using code patching"
2262	# needs Clang with https://reviews.llvm.org/D111780 incorporated
2263	depends on CC_IS_CLANG && CLANG_VERSION >= 150000
2264	depends on ARM64_PTR_AUTH_KERNEL && CC_HAS_BRANCH_PROT_PAC_RET
2265	depends on SHADOW_CALL_STACK
2266	select UNWIND_TABLES
2267	select DYNAMIC_SCS
2268
2269endmenu # "Kernel Features"
2270
2271menu "Boot options"
2272
2273config ARM64_ACPI_PARKING_PROTOCOL
2274	bool "Enable support for the ARM64 ACPI parking protocol"
2275	depends on ACPI
2276	help
2277	  Enable support for the ARM64 ACPI parking protocol. If disabled
2278	  the kernel will not allow booting through the ARM64 ACPI parking
2279	  protocol even if the corresponding data is present in the ACPI
2280	  MADT table.
2281
2282config CMDLINE
2283	string "Default kernel command string"
2284	default ""
2285	help
2286	  Provide a set of default command-line options at build time by
2287	  entering them here. As a minimum, you should specify the the
2288	  root device (e.g. root=/dev/nfs).
2289
2290choice
2291	prompt "Kernel command line type" if CMDLINE != ""
2292	default CMDLINE_FROM_BOOTLOADER
2293	help
2294	  Choose how the kernel will handle the provided default kernel
2295	  command line string.
2296
2297config CMDLINE_FROM_BOOTLOADER
2298	bool "Use bootloader kernel arguments if available"
2299	help
2300	  Uses the command-line options passed by the boot loader. If
2301	  the boot loader doesn't provide any, the default kernel command
2302	  string provided in CMDLINE will be used.
2303
2304config CMDLINE_FORCE
2305	bool "Always use the default kernel command string"
2306	help
2307	  Always use the default kernel command string, even if the boot
2308	  loader passes other arguments to the kernel.
2309	  This is useful if you cannot or don't want to change the
2310	  command-line options your boot loader passes to the kernel.
2311
2312endchoice
2313
2314config EFI_STUB
2315	bool
2316
2317config EFI
2318	bool "UEFI runtime support"
2319	depends on OF && !CPU_BIG_ENDIAN
2320	depends on KERNEL_MODE_NEON
2321	select ARCH_SUPPORTS_ACPI
2322	select LIBFDT
2323	select UCS2_STRING
2324	select EFI_PARAMS_FROM_FDT
2325	select EFI_RUNTIME_WRAPPERS
2326	select EFI_STUB
2327	select EFI_GENERIC_STUB
2328	imply IMA_SECURE_AND_OR_TRUSTED_BOOT
2329	default y
2330	help
2331	  This option provides support for runtime services provided
2332	  by UEFI firmware (such as non-volatile variables, realtime
2333	  clock, and platform reset). A UEFI stub is also provided to
2334	  allow the kernel to be booted as an EFI application. This
2335	  is only useful on systems that have UEFI firmware.
2336
2337config DMI
2338	bool "Enable support for SMBIOS (DMI) tables"
2339	depends on EFI
2340	default y
2341	help
2342	  This enables SMBIOS/DMI feature for systems.
2343
2344	  This option is only useful on systems that have UEFI firmware.
2345	  However, even with this option, the resultant kernel should
2346	  continue to boot on existing non-UEFI platforms.
2347
2348endmenu # "Boot options"
2349
2350menu "Power management options"
2351
2352source "kernel/power/Kconfig"
2353
2354config ARCH_HIBERNATION_POSSIBLE
2355	def_bool y
2356	depends on CPU_PM
2357
2358config ARCH_HIBERNATION_HEADER
2359	def_bool y
2360	depends on HIBERNATION
2361
2362config ARCH_SUSPEND_POSSIBLE
2363	def_bool y
2364
2365endmenu # "Power management options"
2366
2367menu "CPU Power Management"
2368
2369source "drivers/cpuidle/Kconfig"
2370
2371source "drivers/cpufreq/Kconfig"
2372
2373endmenu # "CPU Power Management"
2374
2375source "drivers/acpi/Kconfig"
2376
2377source "arch/arm64/kvm/Kconfig"
2378
2379