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[thirdparty/linux.git] / arch / arm64 / Kconfig
1 # SPDX-License-Identifier: GPL-2.0-only
2 config ARM64
3 def_bool y
4 select ACPI_APMT if ACPI
5 select ACPI_CCA_REQUIRED if ACPI
6 select ACPI_GENERIC_GSI if ACPI
7 select ACPI_GTDT if ACPI
8 select ACPI_IORT if ACPI
9 select ACPI_REDUCED_HARDWARE_ONLY if ACPI
10 select ACPI_MCFG if (ACPI && PCI)
11 select ACPI_SPCR_TABLE if ACPI
12 select ACPI_PPTT if ACPI
13 select ARCH_HAS_DEBUG_WX
14 select ARCH_BINFMT_ELF_EXTRA_PHDRS
15 select ARCH_BINFMT_ELF_STATE
16 select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
17 select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION
18 select ARCH_ENABLE_MEMORY_HOTPLUG
19 select ARCH_ENABLE_MEMORY_HOTREMOVE
20 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
21 select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE
22 select ARCH_HAS_CACHE_LINE_SIZE
23 select ARCH_HAS_CURRENT_STACK_POINTER
24 select ARCH_HAS_DEBUG_VIRTUAL
25 select ARCH_HAS_DEBUG_VM_PGTABLE
26 select ARCH_HAS_DMA_PREP_COHERENT
27 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
28 select ARCH_HAS_FAST_MULTIPLIER
29 select ARCH_HAS_FORTIFY_SOURCE
30 select ARCH_HAS_GCOV_PROFILE_ALL
31 select ARCH_HAS_GIGANTIC_PAGE
32 select ARCH_HAS_KCOV
33 select ARCH_HAS_KEEPINITRD
34 select ARCH_HAS_MEMBARRIER_SYNC_CORE
35 select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
36 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
37 select ARCH_HAS_PTE_DEVMAP
38 select ARCH_HAS_PTE_SPECIAL
39 select ARCH_HAS_SETUP_DMA_OPS
40 select ARCH_HAS_SET_DIRECT_MAP
41 select ARCH_HAS_SET_MEMORY
42 select ARCH_STACKWALK
43 select ARCH_HAS_STRICT_KERNEL_RWX
44 select ARCH_HAS_STRICT_MODULE_RWX
45 select ARCH_HAS_SYNC_DMA_FOR_DEVICE
46 select ARCH_HAS_SYNC_DMA_FOR_CPU
47 select ARCH_HAS_SYSCALL_WRAPPER
48 select ARCH_HAS_TEARDOWN_DMA_OPS if IOMMU_SUPPORT
49 select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
50 select ARCH_HAS_ZONE_DMA_SET if EXPERT
51 select ARCH_HAVE_ELF_PROT
52 select ARCH_HAVE_NMI_SAFE_CMPXCHG
53 select ARCH_HAVE_TRACE_MMIO_ACCESS
54 select ARCH_INLINE_READ_LOCK if !PREEMPTION
55 select ARCH_INLINE_READ_LOCK_BH if !PREEMPTION
56 select ARCH_INLINE_READ_LOCK_IRQ if !PREEMPTION
57 select ARCH_INLINE_READ_LOCK_IRQSAVE if !PREEMPTION
58 select ARCH_INLINE_READ_UNLOCK if !PREEMPTION
59 select ARCH_INLINE_READ_UNLOCK_BH if !PREEMPTION
60 select ARCH_INLINE_READ_UNLOCK_IRQ if !PREEMPTION
61 select ARCH_INLINE_READ_UNLOCK_IRQRESTORE if !PREEMPTION
62 select ARCH_INLINE_WRITE_LOCK if !PREEMPTION
63 select ARCH_INLINE_WRITE_LOCK_BH if !PREEMPTION
64 select ARCH_INLINE_WRITE_LOCK_IRQ if !PREEMPTION
65 select ARCH_INLINE_WRITE_LOCK_IRQSAVE if !PREEMPTION
66 select ARCH_INLINE_WRITE_UNLOCK if !PREEMPTION
67 select ARCH_INLINE_WRITE_UNLOCK_BH if !PREEMPTION
68 select ARCH_INLINE_WRITE_UNLOCK_IRQ if !PREEMPTION
69 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE if !PREEMPTION
70 select ARCH_INLINE_SPIN_TRYLOCK if !PREEMPTION
71 select ARCH_INLINE_SPIN_TRYLOCK_BH if !PREEMPTION
72 select ARCH_INLINE_SPIN_LOCK if !PREEMPTION
73 select ARCH_INLINE_SPIN_LOCK_BH if !PREEMPTION
74 select ARCH_INLINE_SPIN_LOCK_IRQ if !PREEMPTION
75 select ARCH_INLINE_SPIN_LOCK_IRQSAVE if !PREEMPTION
76 select ARCH_INLINE_SPIN_UNLOCK if !PREEMPTION
77 select ARCH_INLINE_SPIN_UNLOCK_BH if !PREEMPTION
78 select ARCH_INLINE_SPIN_UNLOCK_IRQ if !PREEMPTION
79 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPTION
80 select ARCH_KEEP_MEMBLOCK
81 select ARCH_USE_CMPXCHG_LOCKREF
82 select ARCH_USE_GNU_PROPERTY
83 select ARCH_USE_MEMTEST
84 select ARCH_USE_QUEUED_RWLOCKS
85 select ARCH_USE_QUEUED_SPINLOCKS
86 select ARCH_USE_SYM_ANNOTATIONS
87 select ARCH_SUPPORTS_DEBUG_PAGEALLOC
88 select ARCH_SUPPORTS_HUGETLBFS
89 select ARCH_SUPPORTS_MEMORY_FAILURE
90 select ARCH_SUPPORTS_SHADOW_CALL_STACK if CC_HAVE_SHADOW_CALL_STACK
91 select ARCH_SUPPORTS_LTO_CLANG if CPU_LITTLE_ENDIAN
92 select ARCH_SUPPORTS_LTO_CLANG_THIN
93 select ARCH_SUPPORTS_CFI_CLANG
94 select ARCH_SUPPORTS_ATOMIC_RMW
95 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
96 select ARCH_SUPPORTS_NUMA_BALANCING
97 select ARCH_SUPPORTS_PAGE_TABLE_CHECK
98 select ARCH_SUPPORTS_PER_VMA_LOCK
99 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT
100 select ARCH_WANT_DEFAULT_BPF_JIT
101 select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
102 select ARCH_WANT_FRAME_POINTERS
103 select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
104 select ARCH_WANT_LD_ORPHAN_WARN
105 select ARCH_WANTS_NO_INSTR
106 select ARCH_WANTS_THP_SWAP if ARM64_4K_PAGES
107 select ARCH_HAS_UBSAN_SANITIZE_ALL
108 select ARM_AMBA
109 select ARM_ARCH_TIMER
110 select ARM_GIC
111 select AUDIT_ARCH_COMPAT_GENERIC
112 select ARM_GIC_V2M if PCI
113 select ARM_GIC_V3
114 select ARM_GIC_V3_ITS if PCI
115 select ARM_PSCI_FW
116 select BUILDTIME_TABLE_SORT
117 select CLONE_BACKWARDS
118 select COMMON_CLK
119 select CPU_PM if (SUSPEND || CPU_IDLE)
120 select CRC32
121 select DCACHE_WORD_ACCESS
122 select DYNAMIC_FTRACE if FUNCTION_TRACER
123 select DMA_DIRECT_REMAP
124 select EDAC_SUPPORT
125 select FRAME_POINTER
126 select FUNCTION_ALIGNMENT_4B
127 select FUNCTION_ALIGNMENT_8B if DYNAMIC_FTRACE_WITH_CALL_OPS
128 select GENERIC_ALLOCATOR
129 select GENERIC_ARCH_TOPOLOGY
130 select GENERIC_CLOCKEVENTS_BROADCAST
131 select GENERIC_CPU_AUTOPROBE
132 select GENERIC_CPU_VULNERABILITIES
133 select GENERIC_EARLY_IOREMAP
134 select GENERIC_IDLE_POLL_SETUP
135 select GENERIC_IOREMAP
136 select GENERIC_IRQ_IPI
137 select GENERIC_IRQ_PROBE
138 select GENERIC_IRQ_SHOW
139 select GENERIC_IRQ_SHOW_LEVEL
140 select GENERIC_LIB_DEVMEM_IS_ALLOWED
141 select GENERIC_PCI_IOMAP
142 select GENERIC_PTDUMP
143 select GENERIC_SCHED_CLOCK
144 select GENERIC_SMP_IDLE_THREAD
145 select GENERIC_TIME_VSYSCALL
146 select GENERIC_GETTIMEOFDAY
147 select GENERIC_VDSO_TIME_NS
148 select HARDIRQS_SW_RESEND
149 select HAS_IOPORT
150 select HAVE_MOVE_PMD
151 select HAVE_MOVE_PUD
152 select HAVE_PCI
153 select HAVE_ACPI_APEI if (ACPI && EFI)
154 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
155 select HAVE_ARCH_AUDITSYSCALL
156 select HAVE_ARCH_BITREVERSE
157 select HAVE_ARCH_COMPILER_H
158 select HAVE_ARCH_HUGE_VMALLOC
159 select HAVE_ARCH_HUGE_VMAP
160 select HAVE_ARCH_JUMP_LABEL
161 select HAVE_ARCH_JUMP_LABEL_RELATIVE
162 select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48)
163 select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN
164 select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN
165 select HAVE_ARCH_KASAN_HW_TAGS if (HAVE_ARCH_KASAN && ARM64_MTE)
166 # Some instrumentation may be unsound, hence EXPERT
167 select HAVE_ARCH_KCSAN if EXPERT
168 select HAVE_ARCH_KFENCE
169 select HAVE_ARCH_KGDB
170 select HAVE_ARCH_MMAP_RND_BITS
171 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
172 select HAVE_ARCH_PREL32_RELOCATIONS
173 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
174 select HAVE_ARCH_SECCOMP_FILTER
175 select HAVE_ARCH_STACKLEAK
176 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
177 select HAVE_ARCH_TRACEHOOK
178 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
179 select HAVE_ARCH_VMAP_STACK
180 select HAVE_ARM_SMCCC
181 select HAVE_ASM_MODVERSIONS
182 select HAVE_EBPF_JIT
183 select HAVE_C_RECORDMCOUNT
184 select HAVE_CMPXCHG_DOUBLE
185 select HAVE_CMPXCHG_LOCAL
186 select HAVE_CONTEXT_TRACKING_USER
187 select HAVE_DEBUG_KMEMLEAK
188 select HAVE_DMA_CONTIGUOUS
189 select HAVE_DYNAMIC_FTRACE
190 select HAVE_DYNAMIC_FTRACE_WITH_ARGS \
191 if $(cc-option,-fpatchable-function-entry=2)
192 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS \
193 if DYNAMIC_FTRACE_WITH_ARGS && DYNAMIC_FTRACE_WITH_CALL_OPS
194 select HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS \
195 if (DYNAMIC_FTRACE_WITH_ARGS && !CFI_CLANG && \
196 !CC_OPTIMIZE_FOR_SIZE)
197 select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY \
198 if DYNAMIC_FTRACE_WITH_ARGS
199 select HAVE_EFFICIENT_UNALIGNED_ACCESS
200 select HAVE_FAST_GUP
201 select HAVE_FTRACE_MCOUNT_RECORD
202 select HAVE_FUNCTION_TRACER
203 select HAVE_FUNCTION_ERROR_INJECTION
204 select HAVE_FUNCTION_GRAPH_TRACER
205 select HAVE_GCC_PLUGINS
206 select HAVE_HW_BREAKPOINT if PERF_EVENTS
207 select HAVE_IOREMAP_PROT
208 select HAVE_IRQ_TIME_ACCOUNTING
209 select HAVE_KVM
210 select HAVE_MOD_ARCH_SPECIFIC
211 select HAVE_NMI
212 select HAVE_PERF_EVENTS
213 select HAVE_PERF_REGS
214 select HAVE_PERF_USER_STACK_DUMP
215 select HAVE_PREEMPT_DYNAMIC_KEY
216 select HAVE_REGS_AND_STACK_ACCESS_API
217 select HAVE_POSIX_CPU_TIMERS_TASK_WORK
218 select HAVE_FUNCTION_ARG_ACCESS_API
219 select MMU_GATHER_RCU_TABLE_FREE
220 select HAVE_RSEQ
221 select HAVE_STACKPROTECTOR
222 select HAVE_SYSCALL_TRACEPOINTS
223 select HAVE_KPROBES
224 select HAVE_KRETPROBES
225 select HAVE_GENERIC_VDSO
226 select IRQ_DOMAIN
227 select IRQ_FORCED_THREADING
228 select KASAN_VMALLOC if KASAN
229 select MODULES_USE_ELF_RELA
230 select NEED_DMA_MAP_STATE
231 select NEED_SG_DMA_LENGTH
232 select OF
233 select OF_EARLY_FLATTREE
234 select PCI_DOMAINS_GENERIC if PCI
235 select PCI_ECAM if (ACPI && PCI)
236 select PCI_SYSCALL if PCI
237 select POWER_RESET
238 select POWER_SUPPLY
239 select SPARSE_IRQ
240 select SWIOTLB
241 select SYSCTL_EXCEPTION_TRACE
242 select THREAD_INFO_IN_TASK
243 select HAVE_ARCH_USERFAULTFD_MINOR if USERFAULTFD
244 select TRACE_IRQFLAGS_SUPPORT
245 select TRACE_IRQFLAGS_NMI_SUPPORT
246 select HAVE_SOFTIRQ_ON_OWN_STACK
247 help
248 ARM 64-bit (AArch64) Linux support.
249
250 config CLANG_SUPPORTS_DYNAMIC_FTRACE_WITH_ARGS
251 def_bool CC_IS_CLANG
252 # https://github.com/ClangBuiltLinux/linux/issues/1507
253 depends on AS_IS_GNU || (AS_IS_LLVM && (LD_IS_LLD || LD_VERSION >= 23600))
254 select HAVE_DYNAMIC_FTRACE_WITH_ARGS
255
256 config GCC_SUPPORTS_DYNAMIC_FTRACE_WITH_ARGS
257 def_bool CC_IS_GCC
258 depends on $(cc-option,-fpatchable-function-entry=2)
259 select HAVE_DYNAMIC_FTRACE_WITH_ARGS
260
261 config 64BIT
262 def_bool y
263
264 config MMU
265 def_bool y
266
267 config ARM64_PAGE_SHIFT
268 int
269 default 16 if ARM64_64K_PAGES
270 default 14 if ARM64_16K_PAGES
271 default 12
272
273 config ARM64_CONT_PTE_SHIFT
274 int
275 default 5 if ARM64_64K_PAGES
276 default 7 if ARM64_16K_PAGES
277 default 4
278
279 config ARM64_CONT_PMD_SHIFT
280 int
281 default 5 if ARM64_64K_PAGES
282 default 5 if ARM64_16K_PAGES
283 default 4
284
285 config ARCH_MMAP_RND_BITS_MIN
286 default 14 if ARM64_64K_PAGES
287 default 16 if ARM64_16K_PAGES
288 default 18
289
290 # max bits determined by the following formula:
291 # VA_BITS - PAGE_SHIFT - 3
292 config ARCH_MMAP_RND_BITS_MAX
293 default 19 if ARM64_VA_BITS=36
294 default 24 if ARM64_VA_BITS=39
295 default 27 if ARM64_VA_BITS=42
296 default 30 if ARM64_VA_BITS=47
297 default 29 if ARM64_VA_BITS=48 && ARM64_64K_PAGES
298 default 31 if ARM64_VA_BITS=48 && ARM64_16K_PAGES
299 default 33 if ARM64_VA_BITS=48
300 default 14 if ARM64_64K_PAGES
301 default 16 if ARM64_16K_PAGES
302 default 18
303
304 config ARCH_MMAP_RND_COMPAT_BITS_MIN
305 default 7 if ARM64_64K_PAGES
306 default 9 if ARM64_16K_PAGES
307 default 11
308
309 config ARCH_MMAP_RND_COMPAT_BITS_MAX
310 default 16
311
312 config NO_IOPORT_MAP
313 def_bool y if !PCI
314
315 config STACKTRACE_SUPPORT
316 def_bool y
317
318 config ILLEGAL_POINTER_VALUE
319 hex
320 default 0xdead000000000000
321
322 config LOCKDEP_SUPPORT
323 def_bool y
324
325 config GENERIC_BUG
326 def_bool y
327 depends on BUG
328
329 config GENERIC_BUG_RELATIVE_POINTERS
330 def_bool y
331 depends on GENERIC_BUG
332
333 config GENERIC_HWEIGHT
334 def_bool y
335
336 config GENERIC_CSUM
337 def_bool y
338
339 config GENERIC_CALIBRATE_DELAY
340 def_bool y
341
342 config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
343 def_bool y
344
345 config SMP
346 def_bool y
347
348 config KERNEL_MODE_NEON
349 def_bool y
350
351 config FIX_EARLYCON_MEM
352 def_bool y
353
354 config PGTABLE_LEVELS
355 int
356 default 2 if ARM64_16K_PAGES && ARM64_VA_BITS_36
357 default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42
358 default 3 if ARM64_64K_PAGES && (ARM64_VA_BITS_48 || ARM64_VA_BITS_52)
359 default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39
360 default 3 if ARM64_16K_PAGES && ARM64_VA_BITS_47
361 default 4 if !ARM64_64K_PAGES && ARM64_VA_BITS_48
362
363 config ARCH_SUPPORTS_UPROBES
364 def_bool y
365
366 config ARCH_PROC_KCORE_TEXT
367 def_bool y
368
369 config BROKEN_GAS_INST
370 def_bool !$(as-instr,1:\n.inst 0\n.rept . - 1b\n\nnop\n.endr\n)
371
372 config BUILTIN_RETURN_ADDRESS_STRIPS_PAC
373 bool
374 # Clang's __builtin_return_adddress() strips the PAC since 12.0.0
375 # https://reviews.llvm.org/D75044
376 default y if CC_IS_CLANG && (CLANG_VERSION >= 120000)
377 # GCC's __builtin_return_address() strips the PAC since 11.1.0,
378 # and this was backported to 10.2.0, 9.4.0, 8.5.0, but not earlier
379 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94891
380 default y if CC_IS_GCC && (GCC_VERSION >= 110100)
381 default y if CC_IS_GCC && (GCC_VERSION >= 100200) && (GCC_VERSION < 110000)
382 default y if CC_IS_GCC && (GCC_VERSION >= 90400) && (GCC_VERSION < 100000)
383 default y if CC_IS_GCC && (GCC_VERSION >= 80500) && (GCC_VERSION < 90000)
384 default n
385
386 config KASAN_SHADOW_OFFSET
387 hex
388 depends on KASAN_GENERIC || KASAN_SW_TAGS
389 default 0xdfff800000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && !KASAN_SW_TAGS
390 default 0xdfffc00000000000 if ARM64_VA_BITS_47 && !KASAN_SW_TAGS
391 default 0xdffffe0000000000 if ARM64_VA_BITS_42 && !KASAN_SW_TAGS
392 default 0xdfffffc000000000 if ARM64_VA_BITS_39 && !KASAN_SW_TAGS
393 default 0xdffffff800000000 if ARM64_VA_BITS_36 && !KASAN_SW_TAGS
394 default 0xefff800000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && KASAN_SW_TAGS
395 default 0xefffc00000000000 if ARM64_VA_BITS_47 && KASAN_SW_TAGS
396 default 0xeffffe0000000000 if ARM64_VA_BITS_42 && KASAN_SW_TAGS
397 default 0xefffffc000000000 if ARM64_VA_BITS_39 && KASAN_SW_TAGS
398 default 0xeffffff800000000 if ARM64_VA_BITS_36 && KASAN_SW_TAGS
399 default 0xffffffffffffffff
400
401 config UNWIND_TABLES
402 bool
403
404 source "arch/arm64/Kconfig.platforms"
405
406 menu "Kernel Features"
407
408 menu "ARM errata workarounds via the alternatives framework"
409
410 config AMPERE_ERRATUM_AC03_CPU_38
411 bool "AmpereOne: AC03_CPU_38: Certain bits in the Virtualization Translation Control Register and Translation Control Registers do not follow RES0 semantics"
412 default y
413 help
414 This option adds an alternative code sequence to work around Ampere
415 erratum AC03_CPU_38 on AmpereOne.
416
417 The affected design reports FEAT_HAFDBS as not implemented in
418 ID_AA64MMFR1_EL1.HAFDBS, but (V)TCR_ELx.{HA,HD} are not RES0
419 as required by the architecture. The unadvertised HAFDBS
420 implementation suffers from an additional erratum where hardware
421 A/D updates can occur after a PTE has been marked invalid.
422
423 The workaround forces KVM to explicitly set VTCR_EL2.HA to 0,
424 which avoids enabling unadvertised hardware Access Flag management
425 at stage-2.
426
427 If unsure, say Y.
428
429 config ARM64_WORKAROUND_CLEAN_CACHE
430 bool
431
432 config ARM64_ERRATUM_826319
433 bool "Cortex-A53: 826319: System might deadlock if a write cannot complete until read data is accepted"
434 default y
435 select ARM64_WORKAROUND_CLEAN_CACHE
436 help
437 This option adds an alternative code sequence to work around ARM
438 erratum 826319 on Cortex-A53 parts up to r0p2 with an AMBA 4 ACE or
439 AXI master interface and an L2 cache.
440
441 If a Cortex-A53 uses an AMBA AXI4 ACE interface to other processors
442 and is unable to accept a certain write via this interface, it will
443 not progress on read data presented on the read data channel and the
444 system can deadlock.
445
446 The workaround promotes data cache clean instructions to
447 data cache clean-and-invalidate.
448 Please note that this does not necessarily enable the workaround,
449 as it depends on the alternative framework, which will only patch
450 the kernel if an affected CPU is detected.
451
452 If unsure, say Y.
453
454 config ARM64_ERRATUM_827319
455 bool "Cortex-A53: 827319: Data cache clean instructions might cause overlapping transactions to the interconnect"
456 default y
457 select ARM64_WORKAROUND_CLEAN_CACHE
458 help
459 This option adds an alternative code sequence to work around ARM
460 erratum 827319 on Cortex-A53 parts up to r0p2 with an AMBA 5 CHI
461 master interface and an L2 cache.
462
463 Under certain conditions this erratum can cause a clean line eviction
464 to occur at the same time as another transaction to the same address
465 on the AMBA 5 CHI interface, which can cause data corruption if the
466 interconnect reorders the two transactions.
467
468 The workaround promotes data cache clean instructions to
469 data cache clean-and-invalidate.
470 Please note that this does not necessarily enable the workaround,
471 as it depends on the alternative framework, which will only patch
472 the kernel if an affected CPU is detected.
473
474 If unsure, say Y.
475
476 config ARM64_ERRATUM_824069
477 bool "Cortex-A53: 824069: Cache line might not be marked as clean after a CleanShared snoop"
478 default y
479 select ARM64_WORKAROUND_CLEAN_CACHE
480 help
481 This option adds an alternative code sequence to work around ARM
482 erratum 824069 on Cortex-A53 parts up to r0p2 when it is connected
483 to a coherent interconnect.
484
485 If a Cortex-A53 processor is executing a store or prefetch for
486 write instruction at the same time as a processor in another
487 cluster is executing a cache maintenance operation to the same
488 address, then this erratum might cause a clean cache line to be
489 incorrectly marked as dirty.
490
491 The workaround promotes data cache clean instructions to
492 data cache clean-and-invalidate.
493 Please note that this option does not necessarily enable the
494 workaround, as it depends on the alternative framework, which will
495 only patch the kernel if an affected CPU is detected.
496
497 If unsure, say Y.
498
499 config ARM64_ERRATUM_819472
500 bool "Cortex-A53: 819472: Store exclusive instructions might cause data corruption"
501 default y
502 select ARM64_WORKAROUND_CLEAN_CACHE
503 help
504 This option adds an alternative code sequence to work around ARM
505 erratum 819472 on Cortex-A53 parts up to r0p1 with an L2 cache
506 present when it is connected to a coherent interconnect.
507
508 If the processor is executing a load and store exclusive sequence at
509 the same time as a processor in another cluster is executing a cache
510 maintenance operation to the same address, then this erratum might
511 cause data corruption.
512
513 The workaround promotes data cache clean instructions to
514 data cache clean-and-invalidate.
515 Please note that this does not necessarily enable the workaround,
516 as it depends on the alternative framework, which will only patch
517 the kernel if an affected CPU is detected.
518
519 If unsure, say Y.
520
521 config ARM64_ERRATUM_832075
522 bool "Cortex-A57: 832075: possible deadlock on mixing exclusive memory accesses with device loads"
523 default y
524 help
525 This option adds an alternative code sequence to work around ARM
526 erratum 832075 on Cortex-A57 parts up to r1p2.
527
528 Affected Cortex-A57 parts might deadlock when exclusive load/store
529 instructions to Write-Back memory are mixed with Device loads.
530
531 The workaround is to promote device loads to use Load-Acquire
532 semantics.
533 Please note that this does not necessarily enable the workaround,
534 as it depends on the alternative framework, which will only patch
535 the kernel if an affected CPU is detected.
536
537 If unsure, say Y.
538
539 config ARM64_ERRATUM_834220
540 bool "Cortex-A57: 834220: Stage 2 translation fault might be incorrectly reported in presence of a Stage 1 fault"
541 depends on KVM
542 default y
543 help
544 This option adds an alternative code sequence to work around ARM
545 erratum 834220 on Cortex-A57 parts up to r1p2.
546
547 Affected Cortex-A57 parts might report a Stage 2 translation
548 fault as the result of a Stage 1 fault for load crossing a
549 page boundary when there is a permission or device memory
550 alignment fault at Stage 1 and a translation fault at Stage 2.
551
552 The workaround is to verify that the Stage 1 translation
553 doesn't generate a fault before handling the Stage 2 fault.
554 Please note that this does not necessarily enable the workaround,
555 as it depends on the alternative framework, which will only patch
556 the kernel if an affected CPU is detected.
557
558 If unsure, say Y.
559
560 config ARM64_ERRATUM_1742098
561 bool "Cortex-A57/A72: 1742098: ELR recorded incorrectly on interrupt taken between cryptographic instructions in a sequence"
562 depends on COMPAT
563 default y
564 help
565 This option removes the AES hwcap for aarch32 user-space to
566 workaround erratum 1742098 on Cortex-A57 and Cortex-A72.
567
568 Affected parts may corrupt the AES state if an interrupt is
569 taken between a pair of AES instructions. These instructions
570 are only present if the cryptography extensions are present.
571 All software should have a fallback implementation for CPUs
572 that don't implement the cryptography extensions.
573
574 If unsure, say Y.
575
576 config ARM64_ERRATUM_845719
577 bool "Cortex-A53: 845719: a load might read incorrect data"
578 depends on COMPAT
579 default y
580 help
581 This option adds an alternative code sequence to work around ARM
582 erratum 845719 on Cortex-A53 parts up to r0p4.
583
584 When running a compat (AArch32) userspace on an affected Cortex-A53
585 part, a load at EL0 from a virtual address that matches the bottom 32
586 bits of the virtual address used by a recent load at (AArch64) EL1
587 might return incorrect data.
588
589 The workaround is to write the contextidr_el1 register on exception
590 return to a 32-bit task.
591 Please note that this does not necessarily enable the workaround,
592 as it depends on the alternative framework, which will only patch
593 the kernel if an affected CPU is detected.
594
595 If unsure, say Y.
596
597 config ARM64_ERRATUM_843419
598 bool "Cortex-A53: 843419: A load or store might access an incorrect address"
599 default y
600 help
601 This option links the kernel with '--fix-cortex-a53-843419' and
602 enables PLT support to replace certain ADRP instructions, which can
603 cause subsequent memory accesses to use an incorrect address on
604 Cortex-A53 parts up to r0p4.
605
606 If unsure, say Y.
607
608 config ARM64_LD_HAS_FIX_ERRATUM_843419
609 def_bool $(ld-option,--fix-cortex-a53-843419)
610
611 config ARM64_ERRATUM_1024718
612 bool "Cortex-A55: 1024718: Update of DBM/AP bits without break before make might result in incorrect update"
613 default y
614 help
615 This option adds a workaround for ARM Cortex-A55 Erratum 1024718.
616
617 Affected Cortex-A55 cores (all revisions) could cause incorrect
618 update of the hardware dirty bit when the DBM/AP bits are updated
619 without a break-before-make. The workaround is to disable the usage
620 of hardware DBM locally on the affected cores. CPUs not affected by
621 this erratum will continue to use the feature.
622
623 If unsure, say Y.
624
625 config ARM64_ERRATUM_1418040
626 bool "Cortex-A76/Neoverse-N1: MRC read following MRRC read of specific Generic Timer in AArch32 might give incorrect result"
627 default y
628 depends on COMPAT
629 help
630 This option adds a workaround for ARM Cortex-A76/Neoverse-N1
631 errata 1188873 and 1418040.
632
633 Affected Cortex-A76/Neoverse-N1 cores (r0p0 to r3p1) could
634 cause register corruption when accessing the timer registers
635 from AArch32 userspace.
636
637 If unsure, say Y.
638
639 config ARM64_WORKAROUND_SPECULATIVE_AT
640 bool
641
642 config ARM64_ERRATUM_1165522
643 bool "Cortex-A76: 1165522: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
644 default y
645 select ARM64_WORKAROUND_SPECULATIVE_AT
646 help
647 This option adds a workaround for ARM Cortex-A76 erratum 1165522.
648
649 Affected Cortex-A76 cores (r0p0, r1p0, r2p0) could end-up with
650 corrupted TLBs by speculating an AT instruction during a guest
651 context switch.
652
653 If unsure, say Y.
654
655 config ARM64_ERRATUM_1319367
656 bool "Cortex-A57/A72: 1319537: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
657 default y
658 select ARM64_WORKAROUND_SPECULATIVE_AT
659 help
660 This option adds work arounds for ARM Cortex-A57 erratum 1319537
661 and A72 erratum 1319367
662
663 Cortex-A57 and A72 cores could end-up with corrupted TLBs by
664 speculating an AT instruction during a guest context switch.
665
666 If unsure, say Y.
667
668 config ARM64_ERRATUM_1530923
669 bool "Cortex-A55: 1530923: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
670 default y
671 select ARM64_WORKAROUND_SPECULATIVE_AT
672 help
673 This option adds a workaround for ARM Cortex-A55 erratum 1530923.
674
675 Affected Cortex-A55 cores (r0p0, r0p1, r1p0, r2p0) could end-up with
676 corrupted TLBs by speculating an AT instruction during a guest
677 context switch.
678
679 If unsure, say Y.
680
681 config ARM64_WORKAROUND_REPEAT_TLBI
682 bool
683
684 config ARM64_ERRATUM_2441007
685 bool "Cortex-A55: Completion of affected memory accesses might not be guaranteed by completion of a TLBI"
686 default y
687 select ARM64_WORKAROUND_REPEAT_TLBI
688 help
689 This option adds a workaround for ARM Cortex-A55 erratum #2441007.
690
691 Under very rare circumstances, affected Cortex-A55 CPUs
692 may not handle a race between a break-before-make sequence on one
693 CPU, and another CPU accessing the same page. This could allow a
694 store to a page that has been unmapped.
695
696 Work around this by adding the affected CPUs to the list that needs
697 TLB sequences to be done twice.
698
699 If unsure, say Y.
700
701 config ARM64_ERRATUM_1286807
702 bool "Cortex-A76: Modification of the translation table for a virtual address might lead to read-after-read ordering violation"
703 default y
704 select ARM64_WORKAROUND_REPEAT_TLBI
705 help
706 This option adds a workaround for ARM Cortex-A76 erratum 1286807.
707
708 On the affected Cortex-A76 cores (r0p0 to r3p0), if a virtual
709 address for a cacheable mapping of a location is being
710 accessed by a core while another core is remapping the virtual
711 address to a new physical page using the recommended
712 break-before-make sequence, then under very rare circumstances
713 TLBI+DSB completes before a read using the translation being
714 invalidated has been observed by other observers. The
715 workaround repeats the TLBI+DSB operation.
716
717 config ARM64_ERRATUM_1463225
718 bool "Cortex-A76: Software Step might prevent interrupt recognition"
719 default y
720 help
721 This option adds a workaround for Arm Cortex-A76 erratum 1463225.
722
723 On the affected Cortex-A76 cores (r0p0 to r3p1), software stepping
724 of a system call instruction (SVC) can prevent recognition of
725 subsequent interrupts when software stepping is disabled in the
726 exception handler of the system call and either kernel debugging
727 is enabled or VHE is in use.
728
729 Work around the erratum by triggering a dummy step exception
730 when handling a system call from a task that is being stepped
731 in a VHE configuration of the kernel.
732
733 If unsure, say Y.
734
735 config ARM64_ERRATUM_1542419
736 bool "Neoverse-N1: workaround mis-ordering of instruction fetches"
737 default y
738 help
739 This option adds a workaround for ARM Neoverse-N1 erratum
740 1542419.
741
742 Affected Neoverse-N1 cores could execute a stale instruction when
743 modified by another CPU. The workaround depends on a firmware
744 counterpart.
745
746 Workaround the issue by hiding the DIC feature from EL0. This
747 forces user-space to perform cache maintenance.
748
749 If unsure, say Y.
750
751 config ARM64_ERRATUM_1508412
752 bool "Cortex-A77: 1508412: workaround deadlock on sequence of NC/Device load and store exclusive or PAR read"
753 default y
754 help
755 This option adds a workaround for Arm Cortex-A77 erratum 1508412.
756
757 Affected Cortex-A77 cores (r0p0, r1p0) could deadlock on a sequence
758 of a store-exclusive or read of PAR_EL1 and a load with device or
759 non-cacheable memory attributes. The workaround depends on a firmware
760 counterpart.
761
762 KVM guests must also have the workaround implemented or they can
763 deadlock the system.
764
765 Work around the issue by inserting DMB SY barriers around PAR_EL1
766 register reads and warning KVM users. The DMB barrier is sufficient
767 to prevent a speculative PAR_EL1 read.
768
769 If unsure, say Y.
770
771 config ARM64_WORKAROUND_TRBE_OVERWRITE_FILL_MODE
772 bool
773
774 config ARM64_ERRATUM_2051678
775 bool "Cortex-A510: 2051678: disable Hardware Update of the page table dirty bit"
776 default y
777 help
778 This options adds the workaround for ARM Cortex-A510 erratum ARM64_ERRATUM_2051678.
779 Affected Cortex-A510 might not respect the ordering rules for
780 hardware update of the page table's dirty bit. The workaround
781 is to not enable the feature on affected CPUs.
782
783 If unsure, say Y.
784
785 config ARM64_ERRATUM_2077057
786 bool "Cortex-A510: 2077057: workaround software-step corrupting SPSR_EL2"
787 default y
788 help
789 This option adds the workaround for ARM Cortex-A510 erratum 2077057.
790 Affected Cortex-A510 may corrupt SPSR_EL2 when the a step exception is
791 expected, but a Pointer Authentication trap is taken instead. The
792 erratum causes SPSR_EL1 to be copied to SPSR_EL2, which could allow
793 EL1 to cause a return to EL2 with a guest controlled ELR_EL2.
794
795 This can only happen when EL2 is stepping EL1.
796
797 When these conditions occur, the SPSR_EL2 value is unchanged from the
798 previous guest entry, and can be restored from the in-memory copy.
799
800 If unsure, say Y.
801
802 config ARM64_ERRATUM_2658417
803 bool "Cortex-A510: 2658417: remove BF16 support due to incorrect result"
804 default y
805 help
806 This option adds the workaround for ARM Cortex-A510 erratum 2658417.
807 Affected Cortex-A510 (r0p0 to r1p1) may produce the wrong result for
808 BFMMLA or VMMLA instructions in rare circumstances when a pair of
809 A510 CPUs are using shared neon hardware. As the sharing is not
810 discoverable by the kernel, hide the BF16 HWCAP to indicate that
811 user-space should not be using these instructions.
812
813 If unsure, say Y.
814
815 config ARM64_ERRATUM_2119858
816 bool "Cortex-A710/X2: 2119858: workaround TRBE overwriting trace data in FILL mode"
817 default y
818 depends on CORESIGHT_TRBE
819 select ARM64_WORKAROUND_TRBE_OVERWRITE_FILL_MODE
820 help
821 This option adds the workaround for ARM Cortex-A710/X2 erratum 2119858.
822
823 Affected Cortex-A710/X2 cores could overwrite up to 3 cache lines of trace
824 data at the base of the buffer (pointed to by TRBASER_EL1) in FILL mode in
825 the event of a WRAP event.
826
827 Work around the issue by always making sure we move the TRBPTR_EL1 by
828 256 bytes before enabling the buffer and filling the first 256 bytes of
829 the buffer with ETM ignore packets upon disabling.
830
831 If unsure, say Y.
832
833 config ARM64_ERRATUM_2139208
834 bool "Neoverse-N2: 2139208: workaround TRBE overwriting trace data in FILL mode"
835 default y
836 depends on CORESIGHT_TRBE
837 select ARM64_WORKAROUND_TRBE_OVERWRITE_FILL_MODE
838 help
839 This option adds the workaround for ARM Neoverse-N2 erratum 2139208.
840
841 Affected Neoverse-N2 cores could overwrite up to 3 cache lines of trace
842 data at the base of the buffer (pointed to by TRBASER_EL1) in FILL mode in
843 the event of a WRAP event.
844
845 Work around the issue by always making sure we move the TRBPTR_EL1 by
846 256 bytes before enabling the buffer and filling the first 256 bytes of
847 the buffer with ETM ignore packets upon disabling.
848
849 If unsure, say Y.
850
851 config ARM64_WORKAROUND_TSB_FLUSH_FAILURE
852 bool
853
854 config ARM64_ERRATUM_2054223
855 bool "Cortex-A710: 2054223: workaround TSB instruction failing to flush trace"
856 default y
857 select ARM64_WORKAROUND_TSB_FLUSH_FAILURE
858 help
859 Enable workaround for ARM Cortex-A710 erratum 2054223
860
861 Affected cores may fail to flush the trace data on a TSB instruction, when
862 the PE is in trace prohibited state. This will cause losing a few bytes
863 of the trace cached.
864
865 Workaround is to issue two TSB consecutively on affected cores.
866
867 If unsure, say Y.
868
869 config ARM64_ERRATUM_2067961
870 bool "Neoverse-N2: 2067961: workaround TSB instruction failing to flush trace"
871 default y
872 select ARM64_WORKAROUND_TSB_FLUSH_FAILURE
873 help
874 Enable workaround for ARM Neoverse-N2 erratum 2067961
875
876 Affected cores may fail to flush the trace data on a TSB instruction, when
877 the PE is in trace prohibited state. This will cause losing a few bytes
878 of the trace cached.
879
880 Workaround is to issue two TSB consecutively on affected cores.
881
882 If unsure, say Y.
883
884 config ARM64_WORKAROUND_TRBE_WRITE_OUT_OF_RANGE
885 bool
886
887 config ARM64_ERRATUM_2253138
888 bool "Neoverse-N2: 2253138: workaround TRBE writing to address out-of-range"
889 depends on CORESIGHT_TRBE
890 default y
891 select ARM64_WORKAROUND_TRBE_WRITE_OUT_OF_RANGE
892 help
893 This option adds the workaround for ARM Neoverse-N2 erratum 2253138.
894
895 Affected Neoverse-N2 cores might write to an out-of-range address, not reserved
896 for TRBE. Under some conditions, the TRBE might generate a write to the next
897 virtually addressed page following the last page of the TRBE address space
898 (i.e., the TRBLIMITR_EL1.LIMIT), instead of wrapping around to the base.
899
900 Work around this in the driver by always making sure that there is a
901 page beyond the TRBLIMITR_EL1.LIMIT, within the space allowed for the TRBE.
902
903 If unsure, say Y.
904
905 config ARM64_ERRATUM_2224489
906 bool "Cortex-A710/X2: 2224489: workaround TRBE writing to address out-of-range"
907 depends on CORESIGHT_TRBE
908 default y
909 select ARM64_WORKAROUND_TRBE_WRITE_OUT_OF_RANGE
910 help
911 This option adds the workaround for ARM Cortex-A710/X2 erratum 2224489.
912
913 Affected Cortex-A710/X2 cores might write to an out-of-range address, not reserved
914 for TRBE. Under some conditions, the TRBE might generate a write to the next
915 virtually addressed page following the last page of the TRBE address space
916 (i.e., the TRBLIMITR_EL1.LIMIT), instead of wrapping around to the base.
917
918 Work around this in the driver by always making sure that there is a
919 page beyond the TRBLIMITR_EL1.LIMIT, within the space allowed for the TRBE.
920
921 If unsure, say Y.
922
923 config ARM64_ERRATUM_2441009
924 bool "Cortex-A510: Completion of affected memory accesses might not be guaranteed by completion of a TLBI"
925 default y
926 select ARM64_WORKAROUND_REPEAT_TLBI
927 help
928 This option adds a workaround for ARM Cortex-A510 erratum #2441009.
929
930 Under very rare circumstances, affected Cortex-A510 CPUs
931 may not handle a race between a break-before-make sequence on one
932 CPU, and another CPU accessing the same page. This could allow a
933 store to a page that has been unmapped.
934
935 Work around this by adding the affected CPUs to the list that needs
936 TLB sequences to be done twice.
937
938 If unsure, say Y.
939
940 config ARM64_ERRATUM_2064142
941 bool "Cortex-A510: 2064142: workaround TRBE register writes while disabled"
942 depends on CORESIGHT_TRBE
943 default y
944 help
945 This option adds the workaround for ARM Cortex-A510 erratum 2064142.
946
947 Affected Cortex-A510 core might fail to write into system registers after the
948 TRBE has been disabled. Under some conditions after the TRBE has been disabled
949 writes into TRBE registers TRBLIMITR_EL1, TRBPTR_EL1, TRBBASER_EL1, TRBSR_EL1,
950 and TRBTRG_EL1 will be ignored and will not be effected.
951
952 Work around this in the driver by executing TSB CSYNC and DSB after collection
953 is stopped and before performing a system register write to one of the affected
954 registers.
955
956 If unsure, say Y.
957
958 config ARM64_ERRATUM_2038923
959 bool "Cortex-A510: 2038923: workaround TRBE corruption with enable"
960 depends on CORESIGHT_TRBE
961 default y
962 help
963 This option adds the workaround for ARM Cortex-A510 erratum 2038923.
964
965 Affected Cortex-A510 core might cause an inconsistent view on whether trace is
966 prohibited within the CPU. As a result, the trace buffer or trace buffer state
967 might be corrupted. This happens after TRBE buffer has been enabled by setting
968 TRBLIMITR_EL1.E, followed by just a single context synchronization event before
969 execution changes from a context, in which trace is prohibited to one where it
970 isn't, or vice versa. In these mentioned conditions, the view of whether trace
971 is prohibited is inconsistent between parts of the CPU, and the trace buffer or
972 the trace buffer state might be corrupted.
973
974 Work around this in the driver by preventing an inconsistent view of whether the
975 trace is prohibited or not based on TRBLIMITR_EL1.E by immediately following a
976 change to TRBLIMITR_EL1.E with at least one ISB instruction before an ERET, or
977 two ISB instructions if no ERET is to take place.
978
979 If unsure, say Y.
980
981 config ARM64_ERRATUM_1902691
982 bool "Cortex-A510: 1902691: workaround TRBE trace corruption"
983 depends on CORESIGHT_TRBE
984 default y
985 help
986 This option adds the workaround for ARM Cortex-A510 erratum 1902691.
987
988 Affected Cortex-A510 core might cause trace data corruption, when being written
989 into the memory. Effectively TRBE is broken and hence cannot be used to capture
990 trace data.
991
992 Work around this problem in the driver by just preventing TRBE initialization on
993 affected cpus. The firmware must have disabled the access to TRBE for the kernel
994 on such implementations. This will cover the kernel for any firmware that doesn't
995 do this already.
996
997 If unsure, say Y.
998
999 config ARM64_ERRATUM_2457168
1000 bool "Cortex-A510: 2457168: workaround for AMEVCNTR01 incrementing incorrectly"
1001 depends on ARM64_AMU_EXTN
1002 default y
1003 help
1004 This option adds the workaround for ARM Cortex-A510 erratum 2457168.
1005
1006 The AMU counter AMEVCNTR01 (constant counter) should increment at the same rate
1007 as the system counter. On affected Cortex-A510 cores AMEVCNTR01 increments
1008 incorrectly giving a significantly higher output value.
1009
1010 Work around this problem by returning 0 when reading the affected counter in
1011 key locations that results in disabling all users of this counter. This effect
1012 is the same to firmware disabling affected counters.
1013
1014 If unsure, say Y.
1015
1016 config ARM64_ERRATUM_2645198
1017 bool "Cortex-A715: 2645198: Workaround possible [ESR|FAR]_ELx corruption"
1018 default y
1019 help
1020 This option adds the workaround for ARM Cortex-A715 erratum 2645198.
1021
1022 If a Cortex-A715 cpu sees a page mapping permissions change from executable
1023 to non-executable, it may corrupt the ESR_ELx and FAR_ELx registers on the
1024 next instruction abort caused by permission fault.
1025
1026 Only user-space does executable to non-executable permission transition via
1027 mprotect() system call. Workaround the problem by doing a break-before-make
1028 TLB invalidation, for all changes to executable user space mappings.
1029
1030 If unsure, say Y.
1031
1032 config CAVIUM_ERRATUM_22375
1033 bool "Cavium erratum 22375, 24313"
1034 default y
1035 help
1036 Enable workaround for errata 22375 and 24313.
1037
1038 This implements two gicv3-its errata workarounds for ThunderX. Both
1039 with a small impact affecting only ITS table allocation.
1040
1041 erratum 22375: only alloc 8MB table size
1042 erratum 24313: ignore memory access type
1043
1044 The fixes are in ITS initialization and basically ignore memory access
1045 type and table size provided by the TYPER and BASER registers.
1046
1047 If unsure, say Y.
1048
1049 config CAVIUM_ERRATUM_23144
1050 bool "Cavium erratum 23144: ITS SYNC hang on dual socket system"
1051 depends on NUMA
1052 default y
1053 help
1054 ITS SYNC command hang for cross node io and collections/cpu mapping.
1055
1056 If unsure, say Y.
1057
1058 config CAVIUM_ERRATUM_23154
1059 bool "Cavium errata 23154 and 38545: GICv3 lacks HW synchronisation"
1060 default y
1061 help
1062 The ThunderX GICv3 implementation requires a modified version for
1063 reading the IAR status to ensure data synchronization
1064 (access to icc_iar1_el1 is not sync'ed before and after).
1065
1066 It also suffers from erratum 38545 (also present on Marvell's
1067 OcteonTX and OcteonTX2), resulting in deactivated interrupts being
1068 spuriously presented to the CPU interface.
1069
1070 If unsure, say Y.
1071
1072 config CAVIUM_ERRATUM_27456
1073 bool "Cavium erratum 27456: Broadcast TLBI instructions may cause icache corruption"
1074 default y
1075 help
1076 On ThunderX T88 pass 1.x through 2.1 parts, broadcast TLBI
1077 instructions may cause the icache to become corrupted if it
1078 contains data for a non-current ASID. The fix is to
1079 invalidate the icache when changing the mm context.
1080
1081 If unsure, say Y.
1082
1083 config CAVIUM_ERRATUM_30115
1084 bool "Cavium erratum 30115: Guest may disable interrupts in host"
1085 default y
1086 help
1087 On ThunderX T88 pass 1.x through 2.2, T81 pass 1.0 through
1088 1.2, and T83 Pass 1.0, KVM guest execution may disable
1089 interrupts in host. Trapping both GICv3 group-0 and group-1
1090 accesses sidesteps the issue.
1091
1092 If unsure, say Y.
1093
1094 config CAVIUM_TX2_ERRATUM_219
1095 bool "Cavium ThunderX2 erratum 219: PRFM between TTBR change and ISB fails"
1096 default y
1097 help
1098 On Cavium ThunderX2, a load, store or prefetch instruction between a
1099 TTBR update and the corresponding context synchronizing operation can
1100 cause a spurious Data Abort to be delivered to any hardware thread in
1101 the CPU core.
1102
1103 Work around the issue by avoiding the problematic code sequence and
1104 trapping KVM guest TTBRx_EL1 writes to EL2 when SMT is enabled. The
1105 trap handler performs the corresponding register access, skips the
1106 instruction and ensures context synchronization by virtue of the
1107 exception return.
1108
1109 If unsure, say Y.
1110
1111 config FUJITSU_ERRATUM_010001
1112 bool "Fujitsu-A64FX erratum E#010001: Undefined fault may occur wrongly"
1113 default y
1114 help
1115 This option adds a workaround for Fujitsu-A64FX erratum E#010001.
1116 On some variants of the Fujitsu-A64FX cores ver(1.0, 1.1), memory
1117 accesses may cause undefined fault (Data abort, DFSC=0b111111).
1118 This fault occurs under a specific hardware condition when a
1119 load/store instruction performs an address translation using:
1120 case-1 TTBR0_EL1 with TCR_EL1.NFD0 == 1.
1121 case-2 TTBR0_EL2 with TCR_EL2.NFD0 == 1.
1122 case-3 TTBR1_EL1 with TCR_EL1.NFD1 == 1.
1123 case-4 TTBR1_EL2 with TCR_EL2.NFD1 == 1.
1124
1125 The workaround is to ensure these bits are clear in TCR_ELx.
1126 The workaround only affects the Fujitsu-A64FX.
1127
1128 If unsure, say Y.
1129
1130 config HISILICON_ERRATUM_161600802
1131 bool "Hip07 161600802: Erroneous redistributor VLPI base"
1132 default y
1133 help
1134 The HiSilicon Hip07 SoC uses the wrong redistributor base
1135 when issued ITS commands such as VMOVP and VMAPP, and requires
1136 a 128kB offset to be applied to the target address in this commands.
1137
1138 If unsure, say Y.
1139
1140 config QCOM_FALKOR_ERRATUM_1003
1141 bool "Falkor E1003: Incorrect translation due to ASID change"
1142 default y
1143 help
1144 On Falkor v1, an incorrect ASID may be cached in the TLB when ASID
1145 and BADDR are changed together in TTBRx_EL1. Since we keep the ASID
1146 in TTBR1_EL1, this situation only occurs in the entry trampoline and
1147 then only for entries in the walk cache, since the leaf translation
1148 is unchanged. Work around the erratum by invalidating the walk cache
1149 entries for the trampoline before entering the kernel proper.
1150
1151 config QCOM_FALKOR_ERRATUM_1009
1152 bool "Falkor E1009: Prematurely complete a DSB after a TLBI"
1153 default y
1154 select ARM64_WORKAROUND_REPEAT_TLBI
1155 help
1156 On Falkor v1, the CPU may prematurely complete a DSB following a
1157 TLBI xxIS invalidate maintenance operation. Repeat the TLBI operation
1158 one more time to fix the issue.
1159
1160 If unsure, say Y.
1161
1162 config QCOM_QDF2400_ERRATUM_0065
1163 bool "QDF2400 E0065: Incorrect GITS_TYPER.ITT_Entry_size"
1164 default y
1165 help
1166 On Qualcomm Datacenter Technologies QDF2400 SoC, ITS hardware reports
1167 ITE size incorrectly. The GITS_TYPER.ITT_Entry_size field should have
1168 been indicated as 16Bytes (0xf), not 8Bytes (0x7).
1169
1170 If unsure, say Y.
1171
1172 config QCOM_FALKOR_ERRATUM_E1041
1173 bool "Falkor E1041: Speculative instruction fetches might cause errant memory access"
1174 default y
1175 help
1176 Falkor CPU may speculatively fetch instructions from an improper
1177 memory location when MMU translation is changed from SCTLR_ELn[M]=1
1178 to SCTLR_ELn[M]=0. Prefix an ISB instruction to fix the problem.
1179
1180 If unsure, say Y.
1181
1182 config NVIDIA_CARMEL_CNP_ERRATUM
1183 bool "NVIDIA Carmel CNP: CNP on Carmel semantically different than ARM cores"
1184 default y
1185 help
1186 If CNP is enabled on Carmel cores, non-sharable TLBIs on a core will not
1187 invalidate shared TLB entries installed by a different core, as it would
1188 on standard ARM cores.
1189
1190 If unsure, say Y.
1191
1192 config ROCKCHIP_ERRATUM_3588001
1193 bool "Rockchip 3588001: GIC600 can not support shareability attributes"
1194 default y
1195 help
1196 The Rockchip RK3588 GIC600 SoC integration does not support ACE/ACE-lite.
1197 This means, that its sharability feature may not be used, even though it
1198 is supported by the IP itself.
1199
1200 If unsure, say Y.
1201
1202 config SOCIONEXT_SYNQUACER_PREITS
1203 bool "Socionext Synquacer: Workaround for GICv3 pre-ITS"
1204 default y
1205 help
1206 Socionext Synquacer SoCs implement a separate h/w block to generate
1207 MSI doorbell writes with non-zero values for the device ID.
1208
1209 If unsure, say Y.
1210
1211 endmenu # "ARM errata workarounds via the alternatives framework"
1212
1213 choice
1214 prompt "Page size"
1215 default ARM64_4K_PAGES
1216 help
1217 Page size (translation granule) configuration.
1218
1219 config ARM64_4K_PAGES
1220 bool "4KB"
1221 help
1222 This feature enables 4KB pages support.
1223
1224 config ARM64_16K_PAGES
1225 bool "16KB"
1226 help
1227 The system will use 16KB pages support. AArch32 emulation
1228 requires applications compiled with 16K (or a multiple of 16K)
1229 aligned segments.
1230
1231 config ARM64_64K_PAGES
1232 bool "64KB"
1233 help
1234 This feature enables 64KB pages support (4KB by default)
1235 allowing only two levels of page tables and faster TLB
1236 look-up. AArch32 emulation requires applications compiled
1237 with 64K aligned segments.
1238
1239 endchoice
1240
1241 choice
1242 prompt "Virtual address space size"
1243 default ARM64_VA_BITS_39 if ARM64_4K_PAGES
1244 default ARM64_VA_BITS_47 if ARM64_16K_PAGES
1245 default ARM64_VA_BITS_42 if ARM64_64K_PAGES
1246 help
1247 Allows choosing one of multiple possible virtual address
1248 space sizes. The level of translation table is determined by
1249 a combination of page size and virtual address space size.
1250
1251 config ARM64_VA_BITS_36
1252 bool "36-bit" if EXPERT
1253 depends on ARM64_16K_PAGES
1254
1255 config ARM64_VA_BITS_39
1256 bool "39-bit"
1257 depends on ARM64_4K_PAGES
1258
1259 config ARM64_VA_BITS_42
1260 bool "42-bit"
1261 depends on ARM64_64K_PAGES
1262
1263 config ARM64_VA_BITS_47
1264 bool "47-bit"
1265 depends on ARM64_16K_PAGES
1266
1267 config ARM64_VA_BITS_48
1268 bool "48-bit"
1269
1270 config ARM64_VA_BITS_52
1271 bool "52-bit"
1272 depends on ARM64_64K_PAGES && (ARM64_PAN || !ARM64_SW_TTBR0_PAN)
1273 help
1274 Enable 52-bit virtual addressing for userspace when explicitly
1275 requested via a hint to mmap(). The kernel will also use 52-bit
1276 virtual addresses for its own mappings (provided HW support for
1277 this feature is available, otherwise it reverts to 48-bit).
1278
1279 NOTE: Enabling 52-bit virtual addressing in conjunction with
1280 ARMv8.3 Pointer Authentication will result in the PAC being
1281 reduced from 7 bits to 3 bits, which may have a significant
1282 impact on its susceptibility to brute-force attacks.
1283
1284 If unsure, select 48-bit virtual addressing instead.
1285
1286 endchoice
1287
1288 config ARM64_FORCE_52BIT
1289 bool "Force 52-bit virtual addresses for userspace"
1290 depends on ARM64_VA_BITS_52 && EXPERT
1291 help
1292 For systems with 52-bit userspace VAs enabled, the kernel will attempt
1293 to maintain compatibility with older software by providing 48-bit VAs
1294 unless a hint is supplied to mmap.
1295
1296 This configuration option disables the 48-bit compatibility logic, and
1297 forces all userspace addresses to be 52-bit on HW that supports it. One
1298 should only enable this configuration option for stress testing userspace
1299 memory management code. If unsure say N here.
1300
1301 config ARM64_VA_BITS
1302 int
1303 default 36 if ARM64_VA_BITS_36
1304 default 39 if ARM64_VA_BITS_39
1305 default 42 if ARM64_VA_BITS_42
1306 default 47 if ARM64_VA_BITS_47
1307 default 48 if ARM64_VA_BITS_48
1308 default 52 if ARM64_VA_BITS_52
1309
1310 choice
1311 prompt "Physical address space size"
1312 default ARM64_PA_BITS_48
1313 help
1314 Choose the maximum physical address range that the kernel will
1315 support.
1316
1317 config ARM64_PA_BITS_48
1318 bool "48-bit"
1319
1320 config ARM64_PA_BITS_52
1321 bool "52-bit (ARMv8.2)"
1322 depends on ARM64_64K_PAGES
1323 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
1324 help
1325 Enable support for a 52-bit physical address space, introduced as
1326 part of the ARMv8.2-LPA extension.
1327
1328 With this enabled, the kernel will also continue to work on CPUs that
1329 do not support ARMv8.2-LPA, but with some added memory overhead (and
1330 minor performance overhead).
1331
1332 endchoice
1333
1334 config ARM64_PA_BITS
1335 int
1336 default 48 if ARM64_PA_BITS_48
1337 default 52 if ARM64_PA_BITS_52
1338
1339 choice
1340 prompt "Endianness"
1341 default CPU_LITTLE_ENDIAN
1342 help
1343 Select the endianness of data accesses performed by the CPU. Userspace
1344 applications will need to be compiled and linked for the endianness
1345 that is selected here.
1346
1347 config CPU_BIG_ENDIAN
1348 bool "Build big-endian kernel"
1349 depends on !LD_IS_LLD || LLD_VERSION >= 130000
1350 help
1351 Say Y if you plan on running a kernel with a big-endian userspace.
1352
1353 config CPU_LITTLE_ENDIAN
1354 bool "Build little-endian kernel"
1355 help
1356 Say Y if you plan on running a kernel with a little-endian userspace.
1357 This is usually the case for distributions targeting arm64.
1358
1359 endchoice
1360
1361 config SCHED_MC
1362 bool "Multi-core scheduler support"
1363 help
1364 Multi-core scheduler support improves the CPU scheduler's decision
1365 making when dealing with multi-core CPU chips at a cost of slightly
1366 increased overhead in some places. If unsure say N here.
1367
1368 config SCHED_CLUSTER
1369 bool "Cluster scheduler support"
1370 help
1371 Cluster scheduler support improves the CPU scheduler's decision
1372 making when dealing with machines that have clusters of CPUs.
1373 Cluster usually means a couple of CPUs which are placed closely
1374 by sharing mid-level caches, last-level cache tags or internal
1375 busses.
1376
1377 config SCHED_SMT
1378 bool "SMT scheduler support"
1379 help
1380 Improves the CPU scheduler's decision making when dealing with
1381 MultiThreading at a cost of slightly increased overhead in some
1382 places. If unsure say N here.
1383
1384 config NR_CPUS
1385 int "Maximum number of CPUs (2-4096)"
1386 range 2 4096
1387 default "256"
1388
1389 config HOTPLUG_CPU
1390 bool "Support for hot-pluggable CPUs"
1391 select GENERIC_IRQ_MIGRATION
1392 help
1393 Say Y here to experiment with turning CPUs off and on. CPUs
1394 can be controlled through /sys/devices/system/cpu.
1395
1396 # Common NUMA Features
1397 config NUMA
1398 bool "NUMA Memory Allocation and Scheduler Support"
1399 select GENERIC_ARCH_NUMA
1400 select ACPI_NUMA if ACPI
1401 select OF_NUMA
1402 select HAVE_SETUP_PER_CPU_AREA
1403 select NEED_PER_CPU_EMBED_FIRST_CHUNK
1404 select NEED_PER_CPU_PAGE_FIRST_CHUNK
1405 select USE_PERCPU_NUMA_NODE_ID
1406 help
1407 Enable NUMA (Non-Uniform Memory Access) support.
1408
1409 The kernel will try to allocate memory used by a CPU on the
1410 local memory of the CPU and add some more
1411 NUMA awareness to the kernel.
1412
1413 config NODES_SHIFT
1414 int "Maximum NUMA Nodes (as a power of 2)"
1415 range 1 10
1416 default "4"
1417 depends on NUMA
1418 help
1419 Specify the maximum number of NUMA Nodes available on the target
1420 system. Increases memory reserved to accommodate various tables.
1421
1422 source "kernel/Kconfig.hz"
1423
1424 config ARCH_SPARSEMEM_ENABLE
1425 def_bool y
1426 select SPARSEMEM_VMEMMAP_ENABLE
1427 select SPARSEMEM_VMEMMAP
1428
1429 config HW_PERF_EVENTS
1430 def_bool y
1431 depends on ARM_PMU
1432
1433 # Supported by clang >= 7.0 or GCC >= 12.0.0
1434 config CC_HAVE_SHADOW_CALL_STACK
1435 def_bool $(cc-option, -fsanitize=shadow-call-stack -ffixed-x18)
1436
1437 config PARAVIRT
1438 bool "Enable paravirtualization code"
1439 help
1440 This changes the kernel so it can modify itself when it is run
1441 under a hypervisor, potentially improving performance significantly
1442 over full virtualization.
1443
1444 config PARAVIRT_TIME_ACCOUNTING
1445 bool "Paravirtual steal time accounting"
1446 select PARAVIRT
1447 help
1448 Select this option to enable fine granularity task steal time
1449 accounting. Time spent executing other tasks in parallel with
1450 the current vCPU is discounted from the vCPU power. To account for
1451 that, there can be a small performance impact.
1452
1453 If in doubt, say N here.
1454
1455 config KEXEC
1456 depends on PM_SLEEP_SMP
1457 select KEXEC_CORE
1458 bool "kexec system call"
1459 help
1460 kexec is a system call that implements the ability to shutdown your
1461 current kernel, and to start another kernel. It is like a reboot
1462 but it is independent of the system firmware. And like a reboot
1463 you can start any kernel with it, not just Linux.
1464
1465 config KEXEC_FILE
1466 bool "kexec file based system call"
1467 select KEXEC_CORE
1468 select HAVE_IMA_KEXEC if IMA
1469 help
1470 This is new version of kexec system call. This system call is
1471 file based and takes file descriptors as system call argument
1472 for kernel and initramfs as opposed to list of segments as
1473 accepted by previous system call.
1474
1475 config KEXEC_SIG
1476 bool "Verify kernel signature during kexec_file_load() syscall"
1477 depends on KEXEC_FILE
1478 help
1479 Select this option to verify a signature with loaded kernel
1480 image. If configured, any attempt of loading a image without
1481 valid signature will fail.
1482
1483 In addition to that option, you need to enable signature
1484 verification for the corresponding kernel image type being
1485 loaded in order for this to work.
1486
1487 config KEXEC_IMAGE_VERIFY_SIG
1488 bool "Enable Image signature verification support"
1489 default y
1490 depends on KEXEC_SIG
1491 depends on EFI && SIGNED_PE_FILE_VERIFICATION
1492 help
1493 Enable Image signature verification support.
1494
1495 comment "Support for PE file signature verification disabled"
1496 depends on KEXEC_SIG
1497 depends on !EFI || !SIGNED_PE_FILE_VERIFICATION
1498
1499 config CRASH_DUMP
1500 bool "Build kdump crash kernel"
1501 help
1502 Generate crash dump after being started by kexec. This should
1503 be normally only set in special crash dump kernels which are
1504 loaded in the main kernel with kexec-tools into a specially
1505 reserved region and then later executed after a crash by
1506 kdump/kexec.
1507
1508 For more details see Documentation/admin-guide/kdump/kdump.rst
1509
1510 config TRANS_TABLE
1511 def_bool y
1512 depends on HIBERNATION || KEXEC_CORE
1513
1514 config XEN_DOM0
1515 def_bool y
1516 depends on XEN
1517
1518 config XEN
1519 bool "Xen guest support on ARM64"
1520 depends on ARM64 && OF
1521 select SWIOTLB_XEN
1522 select PARAVIRT
1523 help
1524 Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64.
1525
1526 # include/linux/mmzone.h requires the following to be true:
1527 #
1528 # MAX_ORDER + PAGE_SHIFT <= SECTION_SIZE_BITS
1529 #
1530 # so the maximum value of MAX_ORDER is SECTION_SIZE_BITS - PAGE_SHIFT:
1531 #
1532 # | SECTION_SIZE_BITS | PAGE_SHIFT | max MAX_ORDER | default MAX_ORDER |
1533 # ----+-------------------+--------------+-----------------+--------------------+
1534 # 4K | 27 | 12 | 15 | 10 |
1535 # 16K | 27 | 14 | 13 | 11 |
1536 # 64K | 29 | 16 | 13 | 13 |
1537 config ARCH_FORCE_MAX_ORDER
1538 int
1539 default "13" if ARM64_64K_PAGES
1540 default "11" if ARM64_16K_PAGES
1541 default "10"
1542 help
1543 The kernel page allocator limits the size of maximal physically
1544 contiguous allocations. The limit is called MAX_ORDER and it
1545 defines the maximal power of two of number of pages that can be
1546 allocated as a single contiguous block. This option allows
1547 overriding the default setting when ability to allocate very
1548 large blocks of physically contiguous memory is required.
1549
1550 The maximal size of allocation cannot exceed the size of the
1551 section, so the value of MAX_ORDER should satisfy
1552
1553 MAX_ORDER + PAGE_SHIFT <= SECTION_SIZE_BITS
1554
1555 Don't change if unsure.
1556
1557 config UNMAP_KERNEL_AT_EL0
1558 bool "Unmap kernel when running in userspace (aka \"KAISER\")" if EXPERT
1559 default y
1560 help
1561 Speculation attacks against some high-performance processors can
1562 be used to bypass MMU permission checks and leak kernel data to
1563 userspace. This can be defended against by unmapping the kernel
1564 when running in userspace, mapping it back in on exception entry
1565 via a trampoline page in the vector table.
1566
1567 If unsure, say Y.
1568
1569 config MITIGATE_SPECTRE_BRANCH_HISTORY
1570 bool "Mitigate Spectre style attacks against branch history" if EXPERT
1571 default y
1572 help
1573 Speculation attacks against some high-performance processors can
1574 make use of branch history to influence future speculation.
1575 When taking an exception from user-space, a sequence of branches
1576 or a firmware call overwrites the branch history.
1577
1578 config RODATA_FULL_DEFAULT_ENABLED
1579 bool "Apply r/o permissions of VM areas also to their linear aliases"
1580 default y
1581 help
1582 Apply read-only attributes of VM areas to the linear alias of
1583 the backing pages as well. This prevents code or read-only data
1584 from being modified (inadvertently or intentionally) via another
1585 mapping of the same memory page. This additional enhancement can
1586 be turned off at runtime by passing rodata=[off|on] (and turned on
1587 with rodata=full if this option is set to 'n')
1588
1589 This requires the linear region to be mapped down to pages,
1590 which may adversely affect performance in some cases.
1591
1592 config ARM64_SW_TTBR0_PAN
1593 bool "Emulate Privileged Access Never using TTBR0_EL1 switching"
1594 help
1595 Enabling this option prevents the kernel from accessing
1596 user-space memory directly by pointing TTBR0_EL1 to a reserved
1597 zeroed area and reserved ASID. The user access routines
1598 restore the valid TTBR0_EL1 temporarily.
1599
1600 config ARM64_TAGGED_ADDR_ABI
1601 bool "Enable the tagged user addresses syscall ABI"
1602 default y
1603 help
1604 When this option is enabled, user applications can opt in to a
1605 relaxed ABI via prctl() allowing tagged addresses to be passed
1606 to system calls as pointer arguments. For details, see
1607 Documentation/arm64/tagged-address-abi.rst.
1608
1609 menuconfig COMPAT
1610 bool "Kernel support for 32-bit EL0"
1611 depends on ARM64_4K_PAGES || EXPERT
1612 select HAVE_UID16
1613 select OLD_SIGSUSPEND3
1614 select COMPAT_OLD_SIGACTION
1615 help
1616 This option enables support for a 32-bit EL0 running under a 64-bit
1617 kernel at EL1. AArch32-specific components such as system calls,
1618 the user helper functions, VFP support and the ptrace interface are
1619 handled appropriately by the kernel.
1620
1621 If you use a page size other than 4KB (i.e, 16KB or 64KB), please be aware
1622 that you will only be able to execute AArch32 binaries that were compiled
1623 with page size aligned segments.
1624
1625 If you want to execute 32-bit userspace applications, say Y.
1626
1627 if COMPAT
1628
1629 config KUSER_HELPERS
1630 bool "Enable kuser helpers page for 32-bit applications"
1631 default y
1632 help
1633 Warning: disabling this option may break 32-bit user programs.
1634
1635 Provide kuser helpers to compat tasks. The kernel provides
1636 helper code to userspace in read only form at a fixed location
1637 to allow userspace to be independent of the CPU type fitted to
1638 the system. This permits binaries to be run on ARMv4 through
1639 to ARMv8 without modification.
1640
1641 See Documentation/arm/kernel_user_helpers.rst for details.
1642
1643 However, the fixed address nature of these helpers can be used
1644 by ROP (return orientated programming) authors when creating
1645 exploits.
1646
1647 If all of the binaries and libraries which run on your platform
1648 are built specifically for your platform, and make no use of
1649 these helpers, then you can turn this option off to hinder
1650 such exploits. However, in that case, if a binary or library
1651 relying on those helpers is run, it will not function correctly.
1652
1653 Say N here only if you are absolutely certain that you do not
1654 need these helpers; otherwise, the safe option is to say Y.
1655
1656 config COMPAT_VDSO
1657 bool "Enable vDSO for 32-bit applications"
1658 depends on !CPU_BIG_ENDIAN
1659 depends on (CC_IS_CLANG && LD_IS_LLD) || "$(CROSS_COMPILE_COMPAT)" != ""
1660 select GENERIC_COMPAT_VDSO
1661 default y
1662 help
1663 Place in the process address space of 32-bit applications an
1664 ELF shared object providing fast implementations of gettimeofday
1665 and clock_gettime.
1666
1667 You must have a 32-bit build of glibc 2.22 or later for programs
1668 to seamlessly take advantage of this.
1669
1670 config THUMB2_COMPAT_VDSO
1671 bool "Compile the 32-bit vDSO for Thumb-2 mode" if EXPERT
1672 depends on COMPAT_VDSO
1673 default y
1674 help
1675 Compile the compat vDSO with '-mthumb -fomit-frame-pointer' if y,
1676 otherwise with '-marm'.
1677
1678 config COMPAT_ALIGNMENT_FIXUPS
1679 bool "Fix up misaligned multi-word loads and stores in user space"
1680
1681 menuconfig ARMV8_DEPRECATED
1682 bool "Emulate deprecated/obsolete ARMv8 instructions"
1683 depends on SYSCTL
1684 help
1685 Legacy software support may require certain instructions
1686 that have been deprecated or obsoleted in the architecture.
1687
1688 Enable this config to enable selective emulation of these
1689 features.
1690
1691 If unsure, say Y
1692
1693 if ARMV8_DEPRECATED
1694
1695 config SWP_EMULATION
1696 bool "Emulate SWP/SWPB instructions"
1697 help
1698 ARMv8 obsoletes the use of A32 SWP/SWPB instructions such that
1699 they are always undefined. Say Y here to enable software
1700 emulation of these instructions for userspace using LDXR/STXR.
1701 This feature can be controlled at runtime with the abi.swp
1702 sysctl which is disabled by default.
1703
1704 In some older versions of glibc [<=2.8] SWP is used during futex
1705 trylock() operations with the assumption that the code will not
1706 be preempted. This invalid assumption may be more likely to fail
1707 with SWP emulation enabled, leading to deadlock of the user
1708 application.
1709
1710 NOTE: when accessing uncached shared regions, LDXR/STXR rely
1711 on an external transaction monitoring block called a global
1712 monitor to maintain update atomicity. If your system does not
1713 implement a global monitor, this option can cause programs that
1714 perform SWP operations to uncached memory to deadlock.
1715
1716 If unsure, say Y
1717
1718 config CP15_BARRIER_EMULATION
1719 bool "Emulate CP15 Barrier instructions"
1720 help
1721 The CP15 barrier instructions - CP15ISB, CP15DSB, and
1722 CP15DMB - are deprecated in ARMv8 (and ARMv7). It is
1723 strongly recommended to use the ISB, DSB, and DMB
1724 instructions instead.
1725
1726 Say Y here to enable software emulation of these
1727 instructions for AArch32 userspace code. When this option is
1728 enabled, CP15 barrier usage is traced which can help
1729 identify software that needs updating. This feature can be
1730 controlled at runtime with the abi.cp15_barrier sysctl.
1731
1732 If unsure, say Y
1733
1734 config SETEND_EMULATION
1735 bool "Emulate SETEND instruction"
1736 help
1737 The SETEND instruction alters the data-endianness of the
1738 AArch32 EL0, and is deprecated in ARMv8.
1739
1740 Say Y here to enable software emulation of the instruction
1741 for AArch32 userspace code. This feature can be controlled
1742 at runtime with the abi.setend sysctl.
1743
1744 Note: All the cpus on the system must have mixed endian support at EL0
1745 for this feature to be enabled. If a new CPU - which doesn't support mixed
1746 endian - is hotplugged in after this feature has been enabled, there could
1747 be unexpected results in the applications.
1748
1749 If unsure, say Y
1750 endif # ARMV8_DEPRECATED
1751
1752 endif # COMPAT
1753
1754 menu "ARMv8.1 architectural features"
1755
1756 config ARM64_HW_AFDBM
1757 bool "Support for hardware updates of the Access and Dirty page flags"
1758 default y
1759 help
1760 The ARMv8.1 architecture extensions introduce support for
1761 hardware updates of the access and dirty information in page
1762 table entries. When enabled in TCR_EL1 (HA and HD bits) on
1763 capable processors, accesses to pages with PTE_AF cleared will
1764 set this bit instead of raising an access flag fault.
1765 Similarly, writes to read-only pages with the DBM bit set will
1766 clear the read-only bit (AP[2]) instead of raising a
1767 permission fault.
1768
1769 Kernels built with this configuration option enabled continue
1770 to work on pre-ARMv8.1 hardware and the performance impact is
1771 minimal. If unsure, say Y.
1772
1773 config ARM64_PAN
1774 bool "Enable support for Privileged Access Never (PAN)"
1775 default y
1776 help
1777 Privileged Access Never (PAN; part of the ARMv8.1 Extensions)
1778 prevents the kernel or hypervisor from accessing user-space (EL0)
1779 memory directly.
1780
1781 Choosing this option will cause any unprotected (not using
1782 copy_to_user et al) memory access to fail with a permission fault.
1783
1784 The feature is detected at runtime, and will remain as a 'nop'
1785 instruction if the cpu does not implement the feature.
1786
1787 config AS_HAS_LDAPR
1788 def_bool $(as-instr,.arch_extension rcpc)
1789
1790 config AS_HAS_LSE_ATOMICS
1791 def_bool $(as-instr,.arch_extension lse)
1792
1793 config ARM64_LSE_ATOMICS
1794 bool
1795 default ARM64_USE_LSE_ATOMICS
1796 depends on AS_HAS_LSE_ATOMICS
1797
1798 config ARM64_USE_LSE_ATOMICS
1799 bool "Atomic instructions"
1800 default y
1801 help
1802 As part of the Large System Extensions, ARMv8.1 introduces new
1803 atomic instructions that are designed specifically to scale in
1804 very large systems.
1805
1806 Say Y here to make use of these instructions for the in-kernel
1807 atomic routines. This incurs a small overhead on CPUs that do
1808 not support these instructions and requires the kernel to be
1809 built with binutils >= 2.25 in order for the new instructions
1810 to be used.
1811
1812 endmenu # "ARMv8.1 architectural features"
1813
1814 menu "ARMv8.2 architectural features"
1815
1816 config AS_HAS_ARMV8_2
1817 def_bool $(cc-option,-Wa$(comma)-march=armv8.2-a)
1818
1819 config AS_HAS_SHA3
1820 def_bool $(as-instr,.arch armv8.2-a+sha3)
1821
1822 config ARM64_PMEM
1823 bool "Enable support for persistent memory"
1824 select ARCH_HAS_PMEM_API
1825 select ARCH_HAS_UACCESS_FLUSHCACHE
1826 help
1827 Say Y to enable support for the persistent memory API based on the
1828 ARMv8.2 DCPoP feature.
1829
1830 The feature is detected at runtime, and the kernel will use DC CVAC
1831 operations if DC CVAP is not supported (following the behaviour of
1832 DC CVAP itself if the system does not define a point of persistence).
1833
1834 config ARM64_RAS_EXTN
1835 bool "Enable support for RAS CPU Extensions"
1836 default y
1837 help
1838 CPUs that support the Reliability, Availability and Serviceability
1839 (RAS) Extensions, part of ARMv8.2 are able to track faults and
1840 errors, classify them and report them to software.
1841
1842 On CPUs with these extensions system software can use additional
1843 barriers to determine if faults are pending and read the
1844 classification from a new set of registers.
1845
1846 Selecting this feature will allow the kernel to use these barriers
1847 and access the new registers if the system supports the extension.
1848 Platform RAS features may additionally depend on firmware support.
1849
1850 config ARM64_CNP
1851 bool "Enable support for Common Not Private (CNP) translations"
1852 default y
1853 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
1854 help
1855 Common Not Private (CNP) allows translation table entries to
1856 be shared between different PEs in the same inner shareable
1857 domain, so the hardware can use this fact to optimise the
1858 caching of such entries in the TLB.
1859
1860 Selecting this option allows the CNP feature to be detected
1861 at runtime, and does not affect PEs that do not implement
1862 this feature.
1863
1864 endmenu # "ARMv8.2 architectural features"
1865
1866 menu "ARMv8.3 architectural features"
1867
1868 config ARM64_PTR_AUTH
1869 bool "Enable support for pointer authentication"
1870 default y
1871 help
1872 Pointer authentication (part of the ARMv8.3 Extensions) provides
1873 instructions for signing and authenticating pointers against secret
1874 keys, which can be used to mitigate Return Oriented Programming (ROP)
1875 and other attacks.
1876
1877 This option enables these instructions at EL0 (i.e. for userspace).
1878 Choosing this option will cause the kernel to initialise secret keys
1879 for each process at exec() time, with these keys being
1880 context-switched along with the process.
1881
1882 The feature is detected at runtime. If the feature is not present in
1883 hardware it will not be advertised to userspace/KVM guest nor will it
1884 be enabled.
1885
1886 If the feature is present on the boot CPU but not on a late CPU, then
1887 the late CPU will be parked. Also, if the boot CPU does not have
1888 address auth and the late CPU has then the late CPU will still boot
1889 but with the feature disabled. On such a system, this option should
1890 not be selected.
1891
1892 config ARM64_PTR_AUTH_KERNEL
1893 bool "Use pointer authentication for kernel"
1894 default y
1895 depends on ARM64_PTR_AUTH
1896 depends on (CC_HAS_SIGN_RETURN_ADDRESS || CC_HAS_BRANCH_PROT_PAC_RET) && AS_HAS_ARMV8_3
1897 # Modern compilers insert a .note.gnu.property section note for PAC
1898 # which is only understood by binutils starting with version 2.33.1.
1899 depends on LD_IS_LLD || LD_VERSION >= 23301 || (CC_IS_GCC && GCC_VERSION < 90100)
1900 depends on !CC_IS_CLANG || AS_HAS_CFI_NEGATE_RA_STATE
1901 depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_ARGS)
1902 help
1903 If the compiler supports the -mbranch-protection or
1904 -msign-return-address flag (e.g. GCC 7 or later), then this option
1905 will cause the kernel itself to be compiled with return address
1906 protection. In this case, and if the target hardware is known to
1907 support pointer authentication, then CONFIG_STACKPROTECTOR can be
1908 disabled with minimal loss of protection.
1909
1910 This feature works with FUNCTION_GRAPH_TRACER option only if
1911 DYNAMIC_FTRACE_WITH_ARGS is enabled.
1912
1913 config CC_HAS_BRANCH_PROT_PAC_RET
1914 # GCC 9 or later, clang 8 or later
1915 def_bool $(cc-option,-mbranch-protection=pac-ret+leaf)
1916
1917 config CC_HAS_SIGN_RETURN_ADDRESS
1918 # GCC 7, 8
1919 def_bool $(cc-option,-msign-return-address=all)
1920
1921 config AS_HAS_ARMV8_3
1922 def_bool $(cc-option,-Wa$(comma)-march=armv8.3-a)
1923
1924 config AS_HAS_CFI_NEGATE_RA_STATE
1925 def_bool $(as-instr,.cfi_startproc\n.cfi_negate_ra_state\n.cfi_endproc\n)
1926
1927 endmenu # "ARMv8.3 architectural features"
1928
1929 menu "ARMv8.4 architectural features"
1930
1931 config ARM64_AMU_EXTN
1932 bool "Enable support for the Activity Monitors Unit CPU extension"
1933 default y
1934 help
1935 The activity monitors extension is an optional extension introduced
1936 by the ARMv8.4 CPU architecture. This enables support for version 1
1937 of the activity monitors architecture, AMUv1.
1938
1939 To enable the use of this extension on CPUs that implement it, say Y.
1940
1941 Note that for architectural reasons, firmware _must_ implement AMU
1942 support when running on CPUs that present the activity monitors
1943 extension. The required support is present in:
1944 * Version 1.5 and later of the ARM Trusted Firmware
1945
1946 For kernels that have this configuration enabled but boot with broken
1947 firmware, you may need to say N here until the firmware is fixed.
1948 Otherwise you may experience firmware panics or lockups when
1949 accessing the counter registers. Even if you are not observing these
1950 symptoms, the values returned by the register reads might not
1951 correctly reflect reality. Most commonly, the value read will be 0,
1952 indicating that the counter is not enabled.
1953
1954 config AS_HAS_ARMV8_4
1955 def_bool $(cc-option,-Wa$(comma)-march=armv8.4-a)
1956
1957 config ARM64_TLB_RANGE
1958 bool "Enable support for tlbi range feature"
1959 default y
1960 depends on AS_HAS_ARMV8_4
1961 help
1962 ARMv8.4-TLBI provides TLBI invalidation instruction that apply to a
1963 range of input addresses.
1964
1965 The feature introduces new assembly instructions, and they were
1966 support when binutils >= 2.30.
1967
1968 endmenu # "ARMv8.4 architectural features"
1969
1970 menu "ARMv8.5 architectural features"
1971
1972 config AS_HAS_ARMV8_5
1973 def_bool $(cc-option,-Wa$(comma)-march=armv8.5-a)
1974
1975 config ARM64_BTI
1976 bool "Branch Target Identification support"
1977 default y
1978 help
1979 Branch Target Identification (part of the ARMv8.5 Extensions)
1980 provides a mechanism to limit the set of locations to which computed
1981 branch instructions such as BR or BLR can jump.
1982
1983 To make use of BTI on CPUs that support it, say Y.
1984
1985 BTI is intended to provide complementary protection to other control
1986 flow integrity protection mechanisms, such as the Pointer
1987 authentication mechanism provided as part of the ARMv8.3 Extensions.
1988 For this reason, it does not make sense to enable this option without
1989 also enabling support for pointer authentication. Thus, when
1990 enabling this option you should also select ARM64_PTR_AUTH=y.
1991
1992 Userspace binaries must also be specifically compiled to make use of
1993 this mechanism. If you say N here or the hardware does not support
1994 BTI, such binaries can still run, but you get no additional
1995 enforcement of branch destinations.
1996
1997 config ARM64_BTI_KERNEL
1998 bool "Use Branch Target Identification for kernel"
1999 default y
2000 depends on ARM64_BTI
2001 depends on ARM64_PTR_AUTH_KERNEL
2002 depends on CC_HAS_BRANCH_PROT_PAC_RET_BTI
2003 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94697
2004 depends on !CC_IS_GCC || GCC_VERSION >= 100100
2005 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106671
2006 depends on !CC_IS_GCC
2007 # https://github.com/llvm/llvm-project/commit/a88c722e687e6780dcd6a58718350dc76fcc4cc9
2008 depends on !CC_IS_CLANG || CLANG_VERSION >= 120000
2009 depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_ARGS)
2010 help
2011 Build the kernel with Branch Target Identification annotations
2012 and enable enforcement of this for kernel code. When this option
2013 is enabled and the system supports BTI all kernel code including
2014 modular code must have BTI enabled.
2015
2016 config CC_HAS_BRANCH_PROT_PAC_RET_BTI
2017 # GCC 9 or later, clang 8 or later
2018 def_bool $(cc-option,-mbranch-protection=pac-ret+leaf+bti)
2019
2020 config ARM64_E0PD
2021 bool "Enable support for E0PD"
2022 default y
2023 help
2024 E0PD (part of the ARMv8.5 extensions) allows us to ensure
2025 that EL0 accesses made via TTBR1 always fault in constant time,
2026 providing similar benefits to KASLR as those provided by KPTI, but
2027 with lower overhead and without disrupting legitimate access to
2028 kernel memory such as SPE.
2029
2030 This option enables E0PD for TTBR1 where available.
2031
2032 config ARM64_AS_HAS_MTE
2033 # Initial support for MTE went in binutils 2.32.0, checked with
2034 # ".arch armv8.5-a+memtag" below. However, this was incomplete
2035 # as a late addition to the final architecture spec (LDGM/STGM)
2036 # is only supported in the newer 2.32.x and 2.33 binutils
2037 # versions, hence the extra "stgm" instruction check below.
2038 def_bool $(as-instr,.arch armv8.5-a+memtag\nstgm xzr$(comma)[x0])
2039
2040 config ARM64_MTE
2041 bool "Memory Tagging Extension support"
2042 default y
2043 depends on ARM64_AS_HAS_MTE && ARM64_TAGGED_ADDR_ABI
2044 depends on AS_HAS_ARMV8_5
2045 depends on AS_HAS_LSE_ATOMICS
2046 # Required for tag checking in the uaccess routines
2047 depends on ARM64_PAN
2048 select ARCH_HAS_SUBPAGE_FAULTS
2049 select ARCH_USES_HIGH_VMA_FLAGS
2050 select ARCH_USES_PG_ARCH_X
2051 help
2052 Memory Tagging (part of the ARMv8.5 Extensions) provides
2053 architectural support for run-time, always-on detection of
2054 various classes of memory error to aid with software debugging
2055 to eliminate vulnerabilities arising from memory-unsafe
2056 languages.
2057
2058 This option enables the support for the Memory Tagging
2059 Extension at EL0 (i.e. for userspace).
2060
2061 Selecting this option allows the feature to be detected at
2062 runtime. Any secondary CPU not implementing this feature will
2063 not be allowed a late bring-up.
2064
2065 Userspace binaries that want to use this feature must
2066 explicitly opt in. The mechanism for the userspace is
2067 described in:
2068
2069 Documentation/arm64/memory-tagging-extension.rst.
2070
2071 endmenu # "ARMv8.5 architectural features"
2072
2073 menu "ARMv8.7 architectural features"
2074
2075 config ARM64_EPAN
2076 bool "Enable support for Enhanced Privileged Access Never (EPAN)"
2077 default y
2078 depends on ARM64_PAN
2079 help
2080 Enhanced Privileged Access Never (EPAN) allows Privileged
2081 Access Never to be used with Execute-only mappings.
2082
2083 The feature is detected at runtime, and will remain disabled
2084 if the cpu does not implement the feature.
2085 endmenu # "ARMv8.7 architectural features"
2086
2087 config ARM64_SVE
2088 bool "ARM Scalable Vector Extension support"
2089 default y
2090 help
2091 The Scalable Vector Extension (SVE) is an extension to the AArch64
2092 execution state which complements and extends the SIMD functionality
2093 of the base architecture to support much larger vectors and to enable
2094 additional vectorisation opportunities.
2095
2096 To enable use of this extension on CPUs that implement it, say Y.
2097
2098 On CPUs that support the SVE2 extensions, this option will enable
2099 those too.
2100
2101 Note that for architectural reasons, firmware _must_ implement SVE
2102 support when running on SVE capable hardware. The required support
2103 is present in:
2104
2105 * version 1.5 and later of the ARM Trusted Firmware
2106 * the AArch64 boot wrapper since commit 5e1261e08abf
2107 ("bootwrapper: SVE: Enable SVE for EL2 and below").
2108
2109 For other firmware implementations, consult the firmware documentation
2110 or vendor.
2111
2112 If you need the kernel to boot on SVE-capable hardware with broken
2113 firmware, you may need to say N here until you get your firmware
2114 fixed. Otherwise, you may experience firmware panics or lockups when
2115 booting the kernel. If unsure and you are not observing these
2116 symptoms, you should assume that it is safe to say Y.
2117
2118 config ARM64_SME
2119 bool "ARM Scalable Matrix Extension support"
2120 default y
2121 depends on ARM64_SVE
2122 help
2123 The Scalable Matrix Extension (SME) is an extension to the AArch64
2124 execution state which utilises a substantial subset of the SVE
2125 instruction set, together with the addition of new architectural
2126 register state capable of holding two dimensional matrix tiles to
2127 enable various matrix operations.
2128
2129 config ARM64_PSEUDO_NMI
2130 bool "Support for NMI-like interrupts"
2131 select ARM_GIC_V3
2132 help
2133 Adds support for mimicking Non-Maskable Interrupts through the use of
2134 GIC interrupt priority. This support requires version 3 or later of
2135 ARM GIC.
2136
2137 This high priority configuration for interrupts needs to be
2138 explicitly enabled by setting the kernel parameter
2139 "irqchip.gicv3_pseudo_nmi" to 1.
2140
2141 If unsure, say N
2142
2143 if ARM64_PSEUDO_NMI
2144 config ARM64_DEBUG_PRIORITY_MASKING
2145 bool "Debug interrupt priority masking"
2146 help
2147 This adds runtime checks to functions enabling/disabling
2148 interrupts when using priority masking. The additional checks verify
2149 the validity of ICC_PMR_EL1 when calling concerned functions.
2150
2151 If unsure, say N
2152 endif # ARM64_PSEUDO_NMI
2153
2154 config RELOCATABLE
2155 bool "Build a relocatable kernel image" if EXPERT
2156 select ARCH_HAS_RELR
2157 default y
2158 help
2159 This builds the kernel as a Position Independent Executable (PIE),
2160 which retains all relocation metadata required to relocate the
2161 kernel binary at runtime to a different virtual address than the
2162 address it was linked at.
2163 Since AArch64 uses the RELA relocation format, this requires a
2164 relocation pass at runtime even if the kernel is loaded at the
2165 same address it was linked at.
2166
2167 config RANDOMIZE_BASE
2168 bool "Randomize the address of the kernel image"
2169 select RELOCATABLE
2170 help
2171 Randomizes the virtual address at which the kernel image is
2172 loaded, as a security feature that deters exploit attempts
2173 relying on knowledge of the location of kernel internals.
2174
2175 It is the bootloader's job to provide entropy, by passing a
2176 random u64 value in /chosen/kaslr-seed at kernel entry.
2177
2178 When booting via the UEFI stub, it will invoke the firmware's
2179 EFI_RNG_PROTOCOL implementation (if available) to supply entropy
2180 to the kernel proper. In addition, it will randomise the physical
2181 location of the kernel Image as well.
2182
2183 If unsure, say N.
2184
2185 config RANDOMIZE_MODULE_REGION_FULL
2186 bool "Randomize the module region over a 2 GB range"
2187 depends on RANDOMIZE_BASE
2188 default y
2189 help
2190 Randomizes the location of the module region inside a 2 GB window
2191 covering the core kernel. This way, it is less likely for modules
2192 to leak information about the location of core kernel data structures
2193 but it does imply that function calls between modules and the core
2194 kernel will need to be resolved via veneers in the module PLT.
2195
2196 When this option is not set, the module region will be randomized over
2197 a limited range that contains the [_stext, _etext] interval of the
2198 core kernel, so branch relocations are almost always in range unless
2199 the region is exhausted. In this particular case of region
2200 exhaustion, modules might be able to fall back to a larger 2GB area.
2201
2202 config CC_HAVE_STACKPROTECTOR_SYSREG
2203 def_bool $(cc-option,-mstack-protector-guard=sysreg -mstack-protector-guard-reg=sp_el0 -mstack-protector-guard-offset=0)
2204
2205 config STACKPROTECTOR_PER_TASK
2206 def_bool y
2207 depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_SYSREG
2208
2209 config UNWIND_PATCH_PAC_INTO_SCS
2210 bool "Enable shadow call stack dynamically using code patching"
2211 # needs Clang with https://reviews.llvm.org/D111780 incorporated
2212 depends on CC_IS_CLANG && CLANG_VERSION >= 150000
2213 depends on ARM64_PTR_AUTH_KERNEL && CC_HAS_BRANCH_PROT_PAC_RET
2214 depends on SHADOW_CALL_STACK
2215 select UNWIND_TABLES
2216 select DYNAMIC_SCS
2217
2218 endmenu # "Kernel Features"
2219
2220 menu "Boot options"
2221
2222 config ARM64_ACPI_PARKING_PROTOCOL
2223 bool "Enable support for the ARM64 ACPI parking protocol"
2224 depends on ACPI
2225 help
2226 Enable support for the ARM64 ACPI parking protocol. If disabled
2227 the kernel will not allow booting through the ARM64 ACPI parking
2228 protocol even if the corresponding data is present in the ACPI
2229 MADT table.
2230
2231 config CMDLINE
2232 string "Default kernel command string"
2233 default ""
2234 help
2235 Provide a set of default command-line options at build time by
2236 entering them here. As a minimum, you should specify the the
2237 root device (e.g. root=/dev/nfs).
2238
2239 choice
2240 prompt "Kernel command line type" if CMDLINE != ""
2241 default CMDLINE_FROM_BOOTLOADER
2242 help
2243 Choose how the kernel will handle the provided default kernel
2244 command line string.
2245
2246 config CMDLINE_FROM_BOOTLOADER
2247 bool "Use bootloader kernel arguments if available"
2248 help
2249 Uses the command-line options passed by the boot loader. If
2250 the boot loader doesn't provide any, the default kernel command
2251 string provided in CMDLINE will be used.
2252
2253 config CMDLINE_FORCE
2254 bool "Always use the default kernel command string"
2255 help
2256 Always use the default kernel command string, even if the boot
2257 loader passes other arguments to the kernel.
2258 This is useful if you cannot or don't want to change the
2259 command-line options your boot loader passes to the kernel.
2260
2261 endchoice
2262
2263 config EFI_STUB
2264 bool
2265
2266 config EFI
2267 bool "UEFI runtime support"
2268 depends on OF && !CPU_BIG_ENDIAN
2269 depends on KERNEL_MODE_NEON
2270 select ARCH_SUPPORTS_ACPI
2271 select LIBFDT
2272 select UCS2_STRING
2273 select EFI_PARAMS_FROM_FDT
2274 select EFI_RUNTIME_WRAPPERS
2275 select EFI_STUB
2276 select EFI_GENERIC_STUB
2277 imply IMA_SECURE_AND_OR_TRUSTED_BOOT
2278 default y
2279 help
2280 This option provides support for runtime services provided
2281 by UEFI firmware (such as non-volatile variables, realtime
2282 clock, and platform reset). A UEFI stub is also provided to
2283 allow the kernel to be booted as an EFI application. This
2284 is only useful on systems that have UEFI firmware.
2285
2286 config DMI
2287 bool "Enable support for SMBIOS (DMI) tables"
2288 depends on EFI
2289 default y
2290 help
2291 This enables SMBIOS/DMI feature for systems.
2292
2293 This option is only useful on systems that have UEFI firmware.
2294 However, even with this option, the resultant kernel should
2295 continue to boot on existing non-UEFI platforms.
2296
2297 endmenu # "Boot options"
2298
2299 menu "Power management options"
2300
2301 source "kernel/power/Kconfig"
2302
2303 config ARCH_HIBERNATION_POSSIBLE
2304 def_bool y
2305 depends on CPU_PM
2306
2307 config ARCH_HIBERNATION_HEADER
2308 def_bool y
2309 depends on HIBERNATION
2310
2311 config ARCH_SUSPEND_POSSIBLE
2312 def_bool y
2313
2314 endmenu # "Power management options"
2315
2316 menu "CPU Power Management"
2317
2318 source "drivers/cpuidle/Kconfig"
2319
2320 source "drivers/cpufreq/Kconfig"
2321
2322 endmenu # "CPU Power Management"
2323
2324 source "drivers/acpi/Kconfig"
2325
2326 source "arch/arm64/kvm/Kconfig"
2327