1 # SPDX-License-Identifier: GPL-2.0-only
4 select ACPI_CCA_REQUIRED if ACPI
5 select ACPI_GENERIC_GSI if ACPI
6 select ACPI_GTDT if ACPI
7 select ACPI_IORT if ACPI
8 select ACPI_REDUCED_HARDWARE_ONLY if ACPI
9 select ACPI_MCFG if (ACPI && PCI)
10 select ACPI_SPCR_TABLE if ACPI
11 select ACPI_PPTT if ACPI
12 select ARCH_HAS_DEBUG_WX
13 select ARCH_BINFMT_ELF_STATE
14 select ARCH_HAS_DEBUG_VIRTUAL
15 select ARCH_HAS_DEBUG_VM_PGTABLE
16 select ARCH_HAS_DEVMEM_IS_ALLOWED
17 select ARCH_HAS_DMA_PREP_COHERENT
18 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
19 select ARCH_HAS_FAST_MULTIPLIER
20 select ARCH_HAS_FORTIFY_SOURCE
21 select ARCH_HAS_GCOV_PROFILE_ALL
22 select ARCH_HAS_GIGANTIC_PAGE
24 select ARCH_HAS_KEEPINITRD
25 select ARCH_HAS_MEMBARRIER_SYNC_CORE
26 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
27 select ARCH_HAS_PTE_DEVMAP
28 select ARCH_HAS_PTE_SPECIAL
29 select ARCH_HAS_SETUP_DMA_OPS
30 select ARCH_HAS_SET_DIRECT_MAP
31 select ARCH_HAS_SET_MEMORY
33 select ARCH_HAS_STRICT_KERNEL_RWX
34 select ARCH_HAS_STRICT_MODULE_RWX
35 select ARCH_HAS_SYNC_DMA_FOR_DEVICE
36 select ARCH_HAS_SYNC_DMA_FOR_CPU
37 select ARCH_HAS_SYSCALL_WRAPPER
38 select ARCH_HAS_TEARDOWN_DMA_OPS if IOMMU_SUPPORT
39 select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
40 select ARCH_HAVE_ELF_PROT
41 select ARCH_HAVE_NMI_SAFE_CMPXCHG
42 select ARCH_INLINE_READ_LOCK if !PREEMPTION
43 select ARCH_INLINE_READ_LOCK_BH if !PREEMPTION
44 select ARCH_INLINE_READ_LOCK_IRQ if !PREEMPTION
45 select ARCH_INLINE_READ_LOCK_IRQSAVE if !PREEMPTION
46 select ARCH_INLINE_READ_UNLOCK if !PREEMPTION
47 select ARCH_INLINE_READ_UNLOCK_BH if !PREEMPTION
48 select ARCH_INLINE_READ_UNLOCK_IRQ if !PREEMPTION
49 select ARCH_INLINE_READ_UNLOCK_IRQRESTORE if !PREEMPTION
50 select ARCH_INLINE_WRITE_LOCK if !PREEMPTION
51 select ARCH_INLINE_WRITE_LOCK_BH if !PREEMPTION
52 select ARCH_INLINE_WRITE_LOCK_IRQ if !PREEMPTION
53 select ARCH_INLINE_WRITE_LOCK_IRQSAVE if !PREEMPTION
54 select ARCH_INLINE_WRITE_UNLOCK if !PREEMPTION
55 select ARCH_INLINE_WRITE_UNLOCK_BH if !PREEMPTION
56 select ARCH_INLINE_WRITE_UNLOCK_IRQ if !PREEMPTION
57 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE if !PREEMPTION
58 select ARCH_INLINE_SPIN_TRYLOCK if !PREEMPTION
59 select ARCH_INLINE_SPIN_TRYLOCK_BH if !PREEMPTION
60 select ARCH_INLINE_SPIN_LOCK if !PREEMPTION
61 select ARCH_INLINE_SPIN_LOCK_BH if !PREEMPTION
62 select ARCH_INLINE_SPIN_LOCK_IRQ if !PREEMPTION
63 select ARCH_INLINE_SPIN_LOCK_IRQSAVE if !PREEMPTION
64 select ARCH_INLINE_SPIN_UNLOCK if !PREEMPTION
65 select ARCH_INLINE_SPIN_UNLOCK_BH if !PREEMPTION
66 select ARCH_INLINE_SPIN_UNLOCK_IRQ if !PREEMPTION
67 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPTION
68 select ARCH_KEEP_MEMBLOCK
69 select ARCH_USE_CMPXCHG_LOCKREF
70 select ARCH_USE_GNU_PROPERTY
71 select ARCH_USE_QUEUED_RWLOCKS
72 select ARCH_USE_QUEUED_SPINLOCKS
73 select ARCH_USE_SYM_ANNOTATIONS
74 select ARCH_SUPPORTS_MEMORY_FAILURE
75 select ARCH_SUPPORTS_SHADOW_CALL_STACK if CC_HAVE_SHADOW_CALL_STACK
76 select ARCH_SUPPORTS_ATOMIC_RMW
77 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && (GCC_VERSION >= 50000 || CC_IS_CLANG)
78 select ARCH_SUPPORTS_NUMA_BALANCING
79 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT
80 select ARCH_WANT_DEFAULT_BPF_JIT
81 select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
82 select ARCH_WANT_FRAME_POINTERS
83 select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
84 select ARCH_HAS_UBSAN_SANITIZE_ALL
88 select AUDIT_ARCH_COMPAT_GENERIC
89 select ARM_GIC_V2M if PCI
91 select ARM_GIC_V3_ITS if PCI
93 select BUILDTIME_TABLE_SORT
94 select CLONE_BACKWARDS
96 select CPU_PM if (SUSPEND || CPU_IDLE)
98 select DCACHE_WORD_ACCESS
99 select DMA_DIRECT_REMAP
102 select GENERIC_ALLOCATOR
103 select GENERIC_ARCH_TOPOLOGY
104 select GENERIC_CLOCKEVENTS
105 select GENERIC_CLOCKEVENTS_BROADCAST
106 select GENERIC_CPU_AUTOPROBE
107 select GENERIC_CPU_VULNERABILITIES
108 select GENERIC_EARLY_IOREMAP
109 select GENERIC_IDLE_POLL_SETUP
110 select GENERIC_IRQ_IPI
111 select GENERIC_IRQ_MULTI_HANDLER
112 select GENERIC_IRQ_PROBE
113 select GENERIC_IRQ_SHOW
114 select GENERIC_IRQ_SHOW_LEVEL
115 select GENERIC_PCI_IOMAP
116 select GENERIC_PTDUMP
117 select GENERIC_SCHED_CLOCK
118 select GENERIC_SMP_IDLE_THREAD
119 select GENERIC_STRNCPY_FROM_USER
120 select GENERIC_STRNLEN_USER
121 select GENERIC_TIME_VSYSCALL
122 select GENERIC_GETTIMEOFDAY
123 select GENERIC_VDSO_TIME_NS
124 select HANDLE_DOMAIN_IRQ
125 select HARDIRQS_SW_RESEND
128 select HAVE_ACPI_APEI if (ACPI && EFI)
129 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
130 select HAVE_ARCH_AUDITSYSCALL
131 select HAVE_ARCH_BITREVERSE
132 select HAVE_ARCH_COMPILER_H
133 select HAVE_ARCH_HUGE_VMAP
134 select HAVE_ARCH_JUMP_LABEL
135 select HAVE_ARCH_JUMP_LABEL_RELATIVE
136 select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48)
137 select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN
138 select HAVE_ARCH_KGDB
139 select HAVE_ARCH_MMAP_RND_BITS
140 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
141 select HAVE_ARCH_PREL32_RELOCATIONS
142 select HAVE_ARCH_SECCOMP_FILTER
143 select HAVE_ARCH_STACKLEAK
144 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
145 select HAVE_ARCH_TRACEHOOK
146 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
147 select HAVE_ARCH_VMAP_STACK
148 select HAVE_ARM_SMCCC
149 select HAVE_ASM_MODVERSIONS
151 select HAVE_C_RECORDMCOUNT
152 select HAVE_CMPXCHG_DOUBLE
153 select HAVE_CMPXCHG_LOCAL
154 select HAVE_CONTEXT_TRACKING
155 select HAVE_DEBUG_BUGVERBOSE
156 select HAVE_DEBUG_KMEMLEAK
157 select HAVE_DMA_CONTIGUOUS
158 select HAVE_DYNAMIC_FTRACE
159 select HAVE_DYNAMIC_FTRACE_WITH_REGS \
160 if $(cc-option,-fpatchable-function-entry=2)
161 select HAVE_EFFICIENT_UNALIGNED_ACCESS
163 select HAVE_FTRACE_MCOUNT_RECORD
164 select HAVE_FUNCTION_TRACER
165 select HAVE_FUNCTION_ERROR_INJECTION
166 select HAVE_FUNCTION_GRAPH_TRACER
167 select HAVE_GCC_PLUGINS
168 select HAVE_HW_BREAKPOINT if PERF_EVENTS
169 select HAVE_IRQ_TIME_ACCOUNTING
171 select HAVE_PATA_PLATFORM
172 select HAVE_PERF_EVENTS
173 select HAVE_PERF_REGS
174 select HAVE_PERF_USER_STACK_DUMP
175 select HAVE_REGS_AND_STACK_ACCESS_API
176 select HAVE_FUNCTION_ARG_ACCESS_API
177 select HAVE_FUTEX_CMPXCHG if FUTEX
178 select MMU_GATHER_RCU_TABLE_FREE
180 select HAVE_STACKPROTECTOR
181 select HAVE_SYSCALL_TRACEPOINTS
183 select HAVE_KRETPROBES
184 select HAVE_GENERIC_VDSO
185 select IOMMU_DMA if IOMMU_SUPPORT
187 select IRQ_FORCED_THREADING
188 select MODULES_USE_ELF_RELA
189 select NEED_DMA_MAP_STATE
190 select NEED_SG_DMA_LENGTH
192 select OF_EARLY_FLATTREE
193 select PCI_DOMAINS_GENERIC if PCI
194 select PCI_ECAM if (ACPI && PCI)
195 select PCI_SYSCALL if PCI
201 select SYSCTL_EXCEPTION_TRACE
202 select THREAD_INFO_IN_TASK
204 ARM 64-bit (AArch64) Linux support.
212 config ARM64_PAGE_SHIFT
214 default 16 if ARM64_64K_PAGES
215 default 14 if ARM64_16K_PAGES
218 config ARM64_CONT_PTE_SHIFT
220 default 5 if ARM64_64K_PAGES
221 default 7 if ARM64_16K_PAGES
224 config ARM64_CONT_PMD_SHIFT
226 default 5 if ARM64_64K_PAGES
227 default 5 if ARM64_16K_PAGES
230 config ARCH_MMAP_RND_BITS_MIN
231 default 14 if ARM64_64K_PAGES
232 default 16 if ARM64_16K_PAGES
235 # max bits determined by the following formula:
236 # VA_BITS - PAGE_SHIFT - 3
237 config ARCH_MMAP_RND_BITS_MAX
238 default 19 if ARM64_VA_BITS=36
239 default 24 if ARM64_VA_BITS=39
240 default 27 if ARM64_VA_BITS=42
241 default 30 if ARM64_VA_BITS=47
242 default 29 if ARM64_VA_BITS=48 && ARM64_64K_PAGES
243 default 31 if ARM64_VA_BITS=48 && ARM64_16K_PAGES
244 default 33 if ARM64_VA_BITS=48
245 default 14 if ARM64_64K_PAGES
246 default 16 if ARM64_16K_PAGES
249 config ARCH_MMAP_RND_COMPAT_BITS_MIN
250 default 7 if ARM64_64K_PAGES
251 default 9 if ARM64_16K_PAGES
254 config ARCH_MMAP_RND_COMPAT_BITS_MAX
260 config STACKTRACE_SUPPORT
263 config ILLEGAL_POINTER_VALUE
265 default 0xdead000000000000
267 config LOCKDEP_SUPPORT
270 config TRACE_IRQFLAGS_SUPPORT
277 config GENERIC_BUG_RELATIVE_POINTERS
279 depends on GENERIC_BUG
281 config GENERIC_HWEIGHT
287 config GENERIC_CALIBRATE_DELAY
291 bool "Support DMA zone" if EXPERT
295 bool "Support DMA32 zone" if EXPERT
298 config ARCH_ENABLE_MEMORY_HOTPLUG
301 config ARCH_ENABLE_MEMORY_HOTREMOVE
307 config KERNEL_MODE_NEON
310 config FIX_EARLYCON_MEM
313 config PGTABLE_LEVELS
315 default 2 if ARM64_16K_PAGES && ARM64_VA_BITS_36
316 default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42
317 default 3 if ARM64_64K_PAGES && (ARM64_VA_BITS_48 || ARM64_VA_BITS_52)
318 default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39
319 default 3 if ARM64_16K_PAGES && ARM64_VA_BITS_47
320 default 4 if !ARM64_64K_PAGES && ARM64_VA_BITS_48
322 config ARCH_SUPPORTS_UPROBES
325 config ARCH_PROC_KCORE_TEXT
328 config BROKEN_GAS_INST
329 def_bool !$(as-instr,1:\n.inst 0\n.rept . - 1b\n\nnop\n.endr\n)
331 config KASAN_SHADOW_OFFSET
334 default 0xdfffa00000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && !KASAN_SW_TAGS
335 default 0xdfffd00000000000 if ARM64_VA_BITS_47 && !KASAN_SW_TAGS
336 default 0xdffffe8000000000 if ARM64_VA_BITS_42 && !KASAN_SW_TAGS
337 default 0xdfffffd000000000 if ARM64_VA_BITS_39 && !KASAN_SW_TAGS
338 default 0xdffffffa00000000 if ARM64_VA_BITS_36 && !KASAN_SW_TAGS
339 default 0xefff900000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && KASAN_SW_TAGS
340 default 0xefffc80000000000 if ARM64_VA_BITS_47 && KASAN_SW_TAGS
341 default 0xeffffe4000000000 if ARM64_VA_BITS_42 && KASAN_SW_TAGS
342 default 0xefffffc800000000 if ARM64_VA_BITS_39 && KASAN_SW_TAGS
343 default 0xeffffff900000000 if ARM64_VA_BITS_36 && KASAN_SW_TAGS
344 default 0xffffffffffffffff
346 source "arch/arm64/Kconfig.platforms"
348 menu "Kernel Features"
350 menu "ARM errata workarounds via the alternatives framework"
352 config ARM64_WORKAROUND_CLEAN_CACHE
355 config ARM64_ERRATUM_826319
356 bool "Cortex-A53: 826319: System might deadlock if a write cannot complete until read data is accepted"
358 select ARM64_WORKAROUND_CLEAN_CACHE
360 This option adds an alternative code sequence to work around ARM
361 erratum 826319 on Cortex-A53 parts up to r0p2 with an AMBA 4 ACE or
362 AXI master interface and an L2 cache.
364 If a Cortex-A53 uses an AMBA AXI4 ACE interface to other processors
365 and is unable to accept a certain write via this interface, it will
366 not progress on read data presented on the read data channel and the
369 The workaround promotes data cache clean instructions to
370 data cache clean-and-invalidate.
371 Please note that this does not necessarily enable the workaround,
372 as it depends on the alternative framework, which will only patch
373 the kernel if an affected CPU is detected.
377 config ARM64_ERRATUM_827319
378 bool "Cortex-A53: 827319: Data cache clean instructions might cause overlapping transactions to the interconnect"
380 select ARM64_WORKAROUND_CLEAN_CACHE
382 This option adds an alternative code sequence to work around ARM
383 erratum 827319 on Cortex-A53 parts up to r0p2 with an AMBA 5 CHI
384 master interface and an L2 cache.
386 Under certain conditions this erratum can cause a clean line eviction
387 to occur at the same time as another transaction to the same address
388 on the AMBA 5 CHI interface, which can cause data corruption if the
389 interconnect reorders the two transactions.
391 The workaround promotes data cache clean instructions to
392 data cache clean-and-invalidate.
393 Please note that this does not necessarily enable the workaround,
394 as it depends on the alternative framework, which will only patch
395 the kernel if an affected CPU is detected.
399 config ARM64_ERRATUM_824069
400 bool "Cortex-A53: 824069: Cache line might not be marked as clean after a CleanShared snoop"
402 select ARM64_WORKAROUND_CLEAN_CACHE
404 This option adds an alternative code sequence to work around ARM
405 erratum 824069 on Cortex-A53 parts up to r0p2 when it is connected
406 to a coherent interconnect.
408 If a Cortex-A53 processor is executing a store or prefetch for
409 write instruction at the same time as a processor in another
410 cluster is executing a cache maintenance operation to the same
411 address, then this erratum might cause a clean cache line to be
412 incorrectly marked as dirty.
414 The workaround promotes data cache clean instructions to
415 data cache clean-and-invalidate.
416 Please note that this option does not necessarily enable the
417 workaround, as it depends on the alternative framework, which will
418 only patch the kernel if an affected CPU is detected.
422 config ARM64_ERRATUM_819472
423 bool "Cortex-A53: 819472: Store exclusive instructions might cause data corruption"
425 select ARM64_WORKAROUND_CLEAN_CACHE
427 This option adds an alternative code sequence to work around ARM
428 erratum 819472 on Cortex-A53 parts up to r0p1 with an L2 cache
429 present when it is connected to a coherent interconnect.
431 If the processor is executing a load and store exclusive sequence at
432 the same time as a processor in another cluster is executing a cache
433 maintenance operation to the same address, then this erratum might
434 cause data corruption.
436 The workaround promotes data cache clean instructions to
437 data cache clean-and-invalidate.
438 Please note that this does not necessarily enable the workaround,
439 as it depends on the alternative framework, which will only patch
440 the kernel if an affected CPU is detected.
444 config ARM64_ERRATUM_832075
445 bool "Cortex-A57: 832075: possible deadlock on mixing exclusive memory accesses with device loads"
448 This option adds an alternative code sequence to work around ARM
449 erratum 832075 on Cortex-A57 parts up to r1p2.
451 Affected Cortex-A57 parts might deadlock when exclusive load/store
452 instructions to Write-Back memory are mixed with Device loads.
454 The workaround is to promote device loads to use Load-Acquire
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.
462 config ARM64_ERRATUM_834220
463 bool "Cortex-A57: 834220: Stage 2 translation fault might be incorrectly reported in presence of a Stage 1 fault"
467 This option adds an alternative code sequence to work around ARM
468 erratum 834220 on Cortex-A57 parts up to r1p2.
470 Affected Cortex-A57 parts might report a Stage 2 translation
471 fault as the result of a Stage 1 fault for load crossing a
472 page boundary when there is a permission or device memory
473 alignment fault at Stage 1 and a translation fault at Stage 2.
475 The workaround is to verify that the Stage 1 translation
476 doesn't generate a fault before handling the Stage 2 fault.
477 Please note that this does not necessarily enable the workaround,
478 as it depends on the alternative framework, which will only patch
479 the kernel if an affected CPU is detected.
483 config ARM64_ERRATUM_845719
484 bool "Cortex-A53: 845719: a load might read incorrect data"
488 This option adds an alternative code sequence to work around ARM
489 erratum 845719 on Cortex-A53 parts up to r0p4.
491 When running a compat (AArch32) userspace on an affected Cortex-A53
492 part, a load at EL0 from a virtual address that matches the bottom 32
493 bits of the virtual address used by a recent load at (AArch64) EL1
494 might return incorrect data.
496 The workaround is to write the contextidr_el1 register on exception
497 return to a 32-bit task.
498 Please note that this does not necessarily enable the workaround,
499 as it depends on the alternative framework, which will only patch
500 the kernel if an affected CPU is detected.
504 config ARM64_ERRATUM_843419
505 bool "Cortex-A53: 843419: A load or store might access an incorrect address"
507 select ARM64_MODULE_PLTS if MODULES
509 This option links the kernel with '--fix-cortex-a53-843419' and
510 enables PLT support to replace certain ADRP instructions, which can
511 cause subsequent memory accesses to use an incorrect address on
512 Cortex-A53 parts up to r0p4.
516 config ARM64_ERRATUM_1024718
517 bool "Cortex-A55: 1024718: Update of DBM/AP bits without break before make might result in incorrect update"
520 This option adds a workaround for ARM Cortex-A55 Erratum 1024718.
522 Affected Cortex-A55 cores (r0p0, r0p1, r1p0) could cause incorrect
523 update of the hardware dirty bit when the DBM/AP bits are updated
524 without a break-before-make. The workaround is to disable the usage
525 of hardware DBM locally on the affected cores. CPUs not affected by
526 this erratum will continue to use the feature.
530 config ARM64_ERRATUM_1418040
531 bool "Cortex-A76/Neoverse-N1: MRC read following MRRC read of specific Generic Timer in AArch32 might give incorrect result"
535 This option adds a workaround for ARM Cortex-A76/Neoverse-N1
536 errata 1188873 and 1418040.
538 Affected Cortex-A76/Neoverse-N1 cores (r0p0 to r3p1) could
539 cause register corruption when accessing the timer registers
540 from AArch32 userspace.
544 config ARM64_WORKAROUND_SPECULATIVE_AT
547 config ARM64_ERRATUM_1165522
548 bool "Cortex-A76: 1165522: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
550 select ARM64_WORKAROUND_SPECULATIVE_AT
552 This option adds a workaround for ARM Cortex-A76 erratum 1165522.
554 Affected Cortex-A76 cores (r0p0, r1p0, r2p0) could end-up with
555 corrupted TLBs by speculating an AT instruction during a guest
560 config ARM64_ERRATUM_1319367
561 bool "Cortex-A57/A72: 1319537: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
563 select ARM64_WORKAROUND_SPECULATIVE_AT
565 This option adds work arounds for ARM Cortex-A57 erratum 1319537
566 and A72 erratum 1319367
568 Cortex-A57 and A72 cores could end-up with corrupted TLBs by
569 speculating an AT instruction during a guest context switch.
573 config ARM64_ERRATUM_1530923
574 bool "Cortex-A55: 1530923: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
576 select ARM64_WORKAROUND_SPECULATIVE_AT
578 This option adds a workaround for ARM Cortex-A55 erratum 1530923.
580 Affected Cortex-A55 cores (r0p0, r0p1, r1p0, r2p0) could end-up with
581 corrupted TLBs by speculating an AT instruction during a guest
586 config ARM64_WORKAROUND_REPEAT_TLBI
589 config ARM64_ERRATUM_1286807
590 bool "Cortex-A76: Modification of the translation table for a virtual address might lead to read-after-read ordering violation"
592 select ARM64_WORKAROUND_REPEAT_TLBI
594 This option adds a workaround for ARM Cortex-A76 erratum 1286807.
596 On the affected Cortex-A76 cores (r0p0 to r3p0), if a virtual
597 address for a cacheable mapping of a location is being
598 accessed by a core while another core is remapping the virtual
599 address to a new physical page using the recommended
600 break-before-make sequence, then under very rare circumstances
601 TLBI+DSB completes before a read using the translation being
602 invalidated has been observed by other observers. The
603 workaround repeats the TLBI+DSB operation.
605 config ARM64_ERRATUM_1463225
606 bool "Cortex-A76: Software Step might prevent interrupt recognition"
609 This option adds a workaround for Arm Cortex-A76 erratum 1463225.
611 On the affected Cortex-A76 cores (r0p0 to r3p1), software stepping
612 of a system call instruction (SVC) can prevent recognition of
613 subsequent interrupts when software stepping is disabled in the
614 exception handler of the system call and either kernel debugging
615 is enabled or VHE is in use.
617 Work around the erratum by triggering a dummy step exception
618 when handling a system call from a task that is being stepped
619 in a VHE configuration of the kernel.
623 config ARM64_ERRATUM_1542419
624 bool "Neoverse-N1: workaround mis-ordering of instruction fetches"
627 This option adds a workaround for ARM Neoverse-N1 erratum
630 Affected Neoverse-N1 cores could execute a stale instruction when
631 modified by another CPU. The workaround depends on a firmware
634 Workaround the issue by hiding the DIC feature from EL0. This
635 forces user-space to perform cache maintenance.
639 config CAVIUM_ERRATUM_22375
640 bool "Cavium erratum 22375, 24313"
643 Enable workaround for errata 22375 and 24313.
645 This implements two gicv3-its errata workarounds for ThunderX. Both
646 with a small impact affecting only ITS table allocation.
648 erratum 22375: only alloc 8MB table size
649 erratum 24313: ignore memory access type
651 The fixes are in ITS initialization and basically ignore memory access
652 type and table size provided by the TYPER and BASER registers.
656 config CAVIUM_ERRATUM_23144
657 bool "Cavium erratum 23144: ITS SYNC hang on dual socket system"
661 ITS SYNC command hang for cross node io and collections/cpu mapping.
665 config CAVIUM_ERRATUM_23154
666 bool "Cavium erratum 23154: Access to ICC_IAR1_EL1 is not sync'ed"
669 The gicv3 of ThunderX requires a modified version for
670 reading the IAR status to ensure data synchronization
671 (access to icc_iar1_el1 is not sync'ed before and after).
675 config CAVIUM_ERRATUM_27456
676 bool "Cavium erratum 27456: Broadcast TLBI instructions may cause icache corruption"
679 On ThunderX T88 pass 1.x through 2.1 parts, broadcast TLBI
680 instructions may cause the icache to become corrupted if it
681 contains data for a non-current ASID. The fix is to
682 invalidate the icache when changing the mm context.
686 config CAVIUM_ERRATUM_30115
687 bool "Cavium erratum 30115: Guest may disable interrupts in host"
690 On ThunderX T88 pass 1.x through 2.2, T81 pass 1.0 through
691 1.2, and T83 Pass 1.0, KVM guest execution may disable
692 interrupts in host. Trapping both GICv3 group-0 and group-1
693 accesses sidesteps the issue.
697 config CAVIUM_TX2_ERRATUM_219
698 bool "Cavium ThunderX2 erratum 219: PRFM between TTBR change and ISB fails"
701 On Cavium ThunderX2, a load, store or prefetch instruction between a
702 TTBR update and the corresponding context synchronizing operation can
703 cause a spurious Data Abort to be delivered to any hardware thread in
706 Work around the issue by avoiding the problematic code sequence and
707 trapping KVM guest TTBRx_EL1 writes to EL2 when SMT is enabled. The
708 trap handler performs the corresponding register access, skips the
709 instruction and ensures context synchronization by virtue of the
714 config FUJITSU_ERRATUM_010001
715 bool "Fujitsu-A64FX erratum E#010001: Undefined fault may occur wrongly"
718 This option adds a workaround for Fujitsu-A64FX erratum E#010001.
719 On some variants of the Fujitsu-A64FX cores ver(1.0, 1.1), memory
720 accesses may cause undefined fault (Data abort, DFSC=0b111111).
721 This fault occurs under a specific hardware condition when a
722 load/store instruction performs an address translation using:
723 case-1 TTBR0_EL1 with TCR_EL1.NFD0 == 1.
724 case-2 TTBR0_EL2 with TCR_EL2.NFD0 == 1.
725 case-3 TTBR1_EL1 with TCR_EL1.NFD1 == 1.
726 case-4 TTBR1_EL2 with TCR_EL2.NFD1 == 1.
728 The workaround is to ensure these bits are clear in TCR_ELx.
729 The workaround only affects the Fujitsu-A64FX.
733 config HISILICON_ERRATUM_161600802
734 bool "Hip07 161600802: Erroneous redistributor VLPI base"
737 The HiSilicon Hip07 SoC uses the wrong redistributor base
738 when issued ITS commands such as VMOVP and VMAPP, and requires
739 a 128kB offset to be applied to the target address in this commands.
743 config QCOM_FALKOR_ERRATUM_1003
744 bool "Falkor E1003: Incorrect translation due to ASID change"
747 On Falkor v1, an incorrect ASID may be cached in the TLB when ASID
748 and BADDR are changed together in TTBRx_EL1. Since we keep the ASID
749 in TTBR1_EL1, this situation only occurs in the entry trampoline and
750 then only for entries in the walk cache, since the leaf translation
751 is unchanged. Work around the erratum by invalidating the walk cache
752 entries for the trampoline before entering the kernel proper.
754 config QCOM_FALKOR_ERRATUM_1009
755 bool "Falkor E1009: Prematurely complete a DSB after a TLBI"
757 select ARM64_WORKAROUND_REPEAT_TLBI
759 On Falkor v1, the CPU may prematurely complete a DSB following a
760 TLBI xxIS invalidate maintenance operation. Repeat the TLBI operation
761 one more time to fix the issue.
765 config QCOM_QDF2400_ERRATUM_0065
766 bool "QDF2400 E0065: Incorrect GITS_TYPER.ITT_Entry_size"
769 On Qualcomm Datacenter Technologies QDF2400 SoC, ITS hardware reports
770 ITE size incorrectly. The GITS_TYPER.ITT_Entry_size field should have
771 been indicated as 16Bytes (0xf), not 8Bytes (0x7).
775 config QCOM_FALKOR_ERRATUM_E1041
776 bool "Falkor E1041: Speculative instruction fetches might cause errant memory access"
779 Falkor CPU may speculatively fetch instructions from an improper
780 memory location when MMU translation is changed from SCTLR_ELn[M]=1
781 to SCTLR_ELn[M]=0. Prefix an ISB instruction to fix the problem.
785 config SOCIONEXT_SYNQUACER_PREITS
786 bool "Socionext Synquacer: Workaround for GICv3 pre-ITS"
789 Socionext Synquacer SoCs implement a separate h/w block to generate
790 MSI doorbell writes with non-zero values for the device ID.
799 default ARM64_4K_PAGES
801 Page size (translation granule) configuration.
803 config ARM64_4K_PAGES
806 This feature enables 4KB pages support.
808 config ARM64_16K_PAGES
811 The system will use 16KB pages support. AArch32 emulation
812 requires applications compiled with 16K (or a multiple of 16K)
815 config ARM64_64K_PAGES
818 This feature enables 64KB pages support (4KB by default)
819 allowing only two levels of page tables and faster TLB
820 look-up. AArch32 emulation requires applications compiled
821 with 64K aligned segments.
826 prompt "Virtual address space size"
827 default ARM64_VA_BITS_39 if ARM64_4K_PAGES
828 default ARM64_VA_BITS_47 if ARM64_16K_PAGES
829 default ARM64_VA_BITS_42 if ARM64_64K_PAGES
831 Allows choosing one of multiple possible virtual address
832 space sizes. The level of translation table is determined by
833 a combination of page size and virtual address space size.
835 config ARM64_VA_BITS_36
836 bool "36-bit" if EXPERT
837 depends on ARM64_16K_PAGES
839 config ARM64_VA_BITS_39
841 depends on ARM64_4K_PAGES
843 config ARM64_VA_BITS_42
845 depends on ARM64_64K_PAGES
847 config ARM64_VA_BITS_47
849 depends on ARM64_16K_PAGES
851 config ARM64_VA_BITS_48
854 config ARM64_VA_BITS_52
856 depends on ARM64_64K_PAGES && (ARM64_PAN || !ARM64_SW_TTBR0_PAN)
858 Enable 52-bit virtual addressing for userspace when explicitly
859 requested via a hint to mmap(). The kernel will also use 52-bit
860 virtual addresses for its own mappings (provided HW support for
861 this feature is available, otherwise it reverts to 48-bit).
863 NOTE: Enabling 52-bit virtual addressing in conjunction with
864 ARMv8.3 Pointer Authentication will result in the PAC being
865 reduced from 7 bits to 3 bits, which may have a significant
866 impact on its susceptibility to brute-force attacks.
868 If unsure, select 48-bit virtual addressing instead.
872 config ARM64_FORCE_52BIT
873 bool "Force 52-bit virtual addresses for userspace"
874 depends on ARM64_VA_BITS_52 && EXPERT
876 For systems with 52-bit userspace VAs enabled, the kernel will attempt
877 to maintain compatibility with older software by providing 48-bit VAs
878 unless a hint is supplied to mmap.
880 This configuration option disables the 48-bit compatibility logic, and
881 forces all userspace addresses to be 52-bit on HW that supports it. One
882 should only enable this configuration option for stress testing userspace
883 memory management code. If unsure say N here.
887 default 36 if ARM64_VA_BITS_36
888 default 39 if ARM64_VA_BITS_39
889 default 42 if ARM64_VA_BITS_42
890 default 47 if ARM64_VA_BITS_47
891 default 48 if ARM64_VA_BITS_48
892 default 52 if ARM64_VA_BITS_52
895 prompt "Physical address space size"
896 default ARM64_PA_BITS_48
898 Choose the maximum physical address range that the kernel will
901 config ARM64_PA_BITS_48
904 config ARM64_PA_BITS_52
905 bool "52-bit (ARMv8.2)"
906 depends on ARM64_64K_PAGES
907 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
909 Enable support for a 52-bit physical address space, introduced as
910 part of the ARMv8.2-LPA extension.
912 With this enabled, the kernel will also continue to work on CPUs that
913 do not support ARMv8.2-LPA, but with some added memory overhead (and
914 minor performance overhead).
920 default 48 if ARM64_PA_BITS_48
921 default 52 if ARM64_PA_BITS_52
925 default CPU_LITTLE_ENDIAN
927 Select the endianness of data accesses performed by the CPU. Userspace
928 applications will need to be compiled and linked for the endianness
929 that is selected here.
931 config CPU_BIG_ENDIAN
932 bool "Build big-endian kernel"
934 Say Y if you plan on running a kernel with a big-endian userspace.
936 config CPU_LITTLE_ENDIAN
937 bool "Build little-endian kernel"
939 Say Y if you plan on running a kernel with a little-endian userspace.
940 This is usually the case for distributions targeting arm64.
945 bool "Multi-core scheduler support"
947 Multi-core scheduler support improves the CPU scheduler's decision
948 making when dealing with multi-core CPU chips at a cost of slightly
949 increased overhead in some places. If unsure say N here.
952 bool "SMT scheduler support"
954 Improves the CPU scheduler's decision making when dealing with
955 MultiThreading at a cost of slightly increased overhead in some
956 places. If unsure say N here.
959 int "Maximum number of CPUs (2-4096)"
964 bool "Support for hot-pluggable CPUs"
965 select GENERIC_IRQ_MIGRATION
967 Say Y here to experiment with turning CPUs off and on. CPUs
968 can be controlled through /sys/devices/system/cpu.
970 # Common NUMA Features
972 bool "NUMA Memory Allocation and Scheduler Support"
973 select ACPI_NUMA if ACPI
976 Enable NUMA (Non-Uniform Memory Access) support.
978 The kernel will try to allocate memory used by a CPU on the
979 local memory of the CPU and add some more
980 NUMA awareness to the kernel.
983 int "Maximum NUMA Nodes (as a power of 2)"
986 depends on NEED_MULTIPLE_NODES
988 Specify the maximum number of NUMA Nodes available on the target
989 system. Increases memory reserved to accommodate various tables.
991 config USE_PERCPU_NUMA_NODE_ID
995 config HAVE_SETUP_PER_CPU_AREA
999 config NEED_PER_CPU_EMBED_FIRST_CHUNK
1003 config HOLES_IN_ZONE
1006 source "kernel/Kconfig.hz"
1008 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
1011 config ARCH_SPARSEMEM_ENABLE
1013 select SPARSEMEM_VMEMMAP_ENABLE
1015 config ARCH_SPARSEMEM_DEFAULT
1016 def_bool ARCH_SPARSEMEM_ENABLE
1018 config ARCH_SELECT_MEMORY_MODEL
1019 def_bool ARCH_SPARSEMEM_ENABLE
1021 config ARCH_FLATMEM_ENABLE
1024 config HAVE_ARCH_PFN_VALID
1027 config HW_PERF_EVENTS
1031 config SYS_SUPPORTS_HUGETLBFS
1034 config ARCH_WANT_HUGE_PMD_SHARE
1036 config ARCH_HAS_CACHE_LINE_SIZE
1039 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
1040 def_bool y if PGTABLE_LEVELS > 2
1042 # Supported by clang >= 7.0
1043 config CC_HAVE_SHADOW_CALL_STACK
1044 def_bool $(cc-option, -fsanitize=shadow-call-stack -ffixed-x18)
1047 bool "Enable paravirtualization code"
1049 This changes the kernel so it can modify itself when it is run
1050 under a hypervisor, potentially improving performance significantly
1051 over full virtualization.
1053 config PARAVIRT_TIME_ACCOUNTING
1054 bool "Paravirtual steal time accounting"
1057 Select this option to enable fine granularity task steal time
1058 accounting. Time spent executing other tasks in parallel with
1059 the current vCPU is discounted from the vCPU power. To account for
1060 that, there can be a small performance impact.
1062 If in doubt, say N here.
1065 depends on PM_SLEEP_SMP
1067 bool "kexec system call"
1069 kexec is a system call that implements the ability to shutdown your
1070 current kernel, and to start another kernel. It is like a reboot
1071 but it is independent of the system firmware. And like a reboot
1072 you can start any kernel with it, not just Linux.
1075 bool "kexec file based system call"
1078 This is new version of kexec system call. This system call is
1079 file based and takes file descriptors as system call argument
1080 for kernel and initramfs as opposed to list of segments as
1081 accepted by previous system call.
1084 bool "Verify kernel signature during kexec_file_load() syscall"
1085 depends on KEXEC_FILE
1087 Select this option to verify a signature with loaded kernel
1088 image. If configured, any attempt of loading a image without
1089 valid signature will fail.
1091 In addition to that option, you need to enable signature
1092 verification for the corresponding kernel image type being
1093 loaded in order for this to work.
1095 config KEXEC_IMAGE_VERIFY_SIG
1096 bool "Enable Image signature verification support"
1098 depends on KEXEC_SIG
1099 depends on EFI && SIGNED_PE_FILE_VERIFICATION
1101 Enable Image signature verification support.
1103 comment "Support for PE file signature verification disabled"
1104 depends on KEXEC_SIG
1105 depends on !EFI || !SIGNED_PE_FILE_VERIFICATION
1108 bool "Build kdump crash kernel"
1110 Generate crash dump after being started by kexec. This should
1111 be normally only set in special crash dump kernels which are
1112 loaded in the main kernel with kexec-tools into a specially
1113 reserved region and then later executed after a crash by
1116 For more details see Documentation/admin-guide/kdump/kdump.rst
1123 bool "Xen guest support on ARM64"
1124 depends on ARM64 && OF
1128 Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64.
1130 config FORCE_MAX_ZONEORDER
1132 default "14" if (ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE)
1133 default "12" if (ARM64_16K_PAGES && TRANSPARENT_HUGEPAGE)
1136 The kernel memory allocator divides physically contiguous memory
1137 blocks into "zones", where each zone is a power of two number of
1138 pages. This option selects the largest power of two that the kernel
1139 keeps in the memory allocator. If you need to allocate very large
1140 blocks of physically contiguous memory, then you may need to
1141 increase this value.
1143 This config option is actually maximum order plus one. For example,
1144 a value of 11 means that the largest free memory block is 2^10 pages.
1146 We make sure that we can allocate upto a HugePage size for each configuration.
1148 MAX_ORDER = (PMD_SHIFT - PAGE_SHIFT) + 1 => PAGE_SHIFT - 2
1150 However for 4K, we choose a higher default value, 11 as opposed to 10, giving us
1151 4M allocations matching the default size used by generic code.
1153 config UNMAP_KERNEL_AT_EL0
1154 bool "Unmap kernel when running in userspace (aka \"KAISER\")" if EXPERT
1157 Speculation attacks against some high-performance processors can
1158 be used to bypass MMU permission checks and leak kernel data to
1159 userspace. This can be defended against by unmapping the kernel
1160 when running in userspace, mapping it back in on exception entry
1161 via a trampoline page in the vector table.
1165 config RODATA_FULL_DEFAULT_ENABLED
1166 bool "Apply r/o permissions of VM areas also to their linear aliases"
1169 Apply read-only attributes of VM areas to the linear alias of
1170 the backing pages as well. This prevents code or read-only data
1171 from being modified (inadvertently or intentionally) via another
1172 mapping of the same memory page. This additional enhancement can
1173 be turned off at runtime by passing rodata=[off|on] (and turned on
1174 with rodata=full if this option is set to 'n')
1176 This requires the linear region to be mapped down to pages,
1177 which may adversely affect performance in some cases.
1179 config ARM64_SW_TTBR0_PAN
1180 bool "Emulate Privileged Access Never using TTBR0_EL1 switching"
1182 Enabling this option prevents the kernel from accessing
1183 user-space memory directly by pointing TTBR0_EL1 to a reserved
1184 zeroed area and reserved ASID. The user access routines
1185 restore the valid TTBR0_EL1 temporarily.
1187 config ARM64_TAGGED_ADDR_ABI
1188 bool "Enable the tagged user addresses syscall ABI"
1191 When this option is enabled, user applications can opt in to a
1192 relaxed ABI via prctl() allowing tagged addresses to be passed
1193 to system calls as pointer arguments. For details, see
1194 Documentation/arm64/tagged-address-abi.rst.
1197 bool "Kernel support for 32-bit EL0"
1198 depends on ARM64_4K_PAGES || EXPERT
1199 select COMPAT_BINFMT_ELF if BINFMT_ELF
1201 select OLD_SIGSUSPEND3
1202 select COMPAT_OLD_SIGACTION
1204 This option enables support for a 32-bit EL0 running under a 64-bit
1205 kernel at EL1. AArch32-specific components such as system calls,
1206 the user helper functions, VFP support and the ptrace interface are
1207 handled appropriately by the kernel.
1209 If you use a page size other than 4KB (i.e, 16KB or 64KB), please be aware
1210 that you will only be able to execute AArch32 binaries that were compiled
1211 with page size aligned segments.
1213 If you want to execute 32-bit userspace applications, say Y.
1217 config KUSER_HELPERS
1218 bool "Enable kuser helpers page for 32-bit applications"
1221 Warning: disabling this option may break 32-bit user programs.
1223 Provide kuser helpers to compat tasks. The kernel provides
1224 helper code to userspace in read only form at a fixed location
1225 to allow userspace to be independent of the CPU type fitted to
1226 the system. This permits binaries to be run on ARMv4 through
1227 to ARMv8 without modification.
1229 See Documentation/arm/kernel_user_helpers.rst for details.
1231 However, the fixed address nature of these helpers can be used
1232 by ROP (return orientated programming) authors when creating
1235 If all of the binaries and libraries which run on your platform
1236 are built specifically for your platform, and make no use of
1237 these helpers, then you can turn this option off to hinder
1238 such exploits. However, in that case, if a binary or library
1239 relying on those helpers is run, it will not function correctly.
1241 Say N here only if you are absolutely certain that you do not
1242 need these helpers; otherwise, the safe option is to say Y.
1245 bool "Enable vDSO for 32-bit applications"
1246 depends on !CPU_BIG_ENDIAN && "$(CROSS_COMPILE_COMPAT)" != ""
1247 select GENERIC_COMPAT_VDSO
1250 Place in the process address space of 32-bit applications an
1251 ELF shared object providing fast implementations of gettimeofday
1254 You must have a 32-bit build of glibc 2.22 or later for programs
1255 to seamlessly take advantage of this.
1257 config THUMB2_COMPAT_VDSO
1258 bool "Compile the 32-bit vDSO for Thumb-2 mode" if EXPERT
1259 depends on COMPAT_VDSO
1262 Compile the compat vDSO with '-mthumb -fomit-frame-pointer' if y,
1263 otherwise with '-marm'.
1265 menuconfig ARMV8_DEPRECATED
1266 bool "Emulate deprecated/obsolete ARMv8 instructions"
1269 Legacy software support may require certain instructions
1270 that have been deprecated or obsoleted in the architecture.
1272 Enable this config to enable selective emulation of these
1279 config SWP_EMULATION
1280 bool "Emulate SWP/SWPB instructions"
1282 ARMv8 obsoletes the use of A32 SWP/SWPB instructions such that
1283 they are always undefined. Say Y here to enable software
1284 emulation of these instructions for userspace using LDXR/STXR.
1285 This feature can be controlled at runtime with the abi.swp
1286 sysctl which is disabled by default.
1288 In some older versions of glibc [<=2.8] SWP is used during futex
1289 trylock() operations with the assumption that the code will not
1290 be preempted. This invalid assumption may be more likely to fail
1291 with SWP emulation enabled, leading to deadlock of the user
1294 NOTE: when accessing uncached shared regions, LDXR/STXR rely
1295 on an external transaction monitoring block called a global
1296 monitor to maintain update atomicity. If your system does not
1297 implement a global monitor, this option can cause programs that
1298 perform SWP operations to uncached memory to deadlock.
1302 config CP15_BARRIER_EMULATION
1303 bool "Emulate CP15 Barrier instructions"
1305 The CP15 barrier instructions - CP15ISB, CP15DSB, and
1306 CP15DMB - are deprecated in ARMv8 (and ARMv7). It is
1307 strongly recommended to use the ISB, DSB, and DMB
1308 instructions instead.
1310 Say Y here to enable software emulation of these
1311 instructions for AArch32 userspace code. When this option is
1312 enabled, CP15 barrier usage is traced which can help
1313 identify software that needs updating. This feature can be
1314 controlled at runtime with the abi.cp15_barrier sysctl.
1318 config SETEND_EMULATION
1319 bool "Emulate SETEND instruction"
1321 The SETEND instruction alters the data-endianness of the
1322 AArch32 EL0, and is deprecated in ARMv8.
1324 Say Y here to enable software emulation of the instruction
1325 for AArch32 userspace code. This feature can be controlled
1326 at runtime with the abi.setend sysctl.
1328 Note: All the cpus on the system must have mixed endian support at EL0
1329 for this feature to be enabled. If a new CPU - which doesn't support mixed
1330 endian - is hotplugged in after this feature has been enabled, there could
1331 be unexpected results in the applications.
1338 menu "ARMv8.1 architectural features"
1340 config ARM64_HW_AFDBM
1341 bool "Support for hardware updates of the Access and Dirty page flags"
1344 The ARMv8.1 architecture extensions introduce support for
1345 hardware updates of the access and dirty information in page
1346 table entries. When enabled in TCR_EL1 (HA and HD bits) on
1347 capable processors, accesses to pages with PTE_AF cleared will
1348 set this bit instead of raising an access flag fault.
1349 Similarly, writes to read-only pages with the DBM bit set will
1350 clear the read-only bit (AP[2]) instead of raising a
1353 Kernels built with this configuration option enabled continue
1354 to work on pre-ARMv8.1 hardware and the performance impact is
1355 minimal. If unsure, say Y.
1358 bool "Enable support for Privileged Access Never (PAN)"
1361 Privileged Access Never (PAN; part of the ARMv8.1 Extensions)
1362 prevents the kernel or hypervisor from accessing user-space (EL0)
1365 Choosing this option will cause any unprotected (not using
1366 copy_to_user et al) memory access to fail with a permission fault.
1368 The feature is detected at runtime, and will remain as a 'nop'
1369 instruction if the cpu does not implement the feature.
1371 config ARM64_LSE_ATOMICS
1373 default ARM64_USE_LSE_ATOMICS
1374 depends on $(as-instr,.arch_extension lse)
1376 config ARM64_USE_LSE_ATOMICS
1377 bool "Atomic instructions"
1378 depends on JUMP_LABEL
1381 As part of the Large System Extensions, ARMv8.1 introduces new
1382 atomic instructions that are designed specifically to scale in
1385 Say Y here to make use of these instructions for the in-kernel
1386 atomic routines. This incurs a small overhead on CPUs that do
1387 not support these instructions and requires the kernel to be
1388 built with binutils >= 2.25 in order for the new instructions
1392 bool "Enable support for Virtualization Host Extensions (VHE)"
1395 Virtualization Host Extensions (VHE) allow the kernel to run
1396 directly at EL2 (instead of EL1) on processors that support
1397 it. This leads to better performance for KVM, as they reduce
1398 the cost of the world switch.
1400 Selecting this option allows the VHE feature to be detected
1401 at runtime, and does not affect processors that do not
1402 implement this feature.
1406 menu "ARMv8.2 architectural features"
1409 bool "Enable support for User Access Override (UAO)"
1412 User Access Override (UAO; part of the ARMv8.2 Extensions)
1413 causes the 'unprivileged' variant of the load/store instructions to
1414 be overridden to be privileged.
1416 This option changes get_user() and friends to use the 'unprivileged'
1417 variant of the load/store instructions. This ensures that user-space
1418 really did have access to the supplied memory. When addr_limit is
1419 set to kernel memory the UAO bit will be set, allowing privileged
1420 access to kernel memory.
1422 Choosing this option will cause copy_to_user() et al to use user-space
1425 The feature is detected at runtime, the kernel will use the
1426 regular load/store instructions if the cpu does not implement the
1430 bool "Enable support for persistent memory"
1431 select ARCH_HAS_PMEM_API
1432 select ARCH_HAS_UACCESS_FLUSHCACHE
1434 Say Y to enable support for the persistent memory API based on the
1435 ARMv8.2 DCPoP feature.
1437 The feature is detected at runtime, and the kernel will use DC CVAC
1438 operations if DC CVAP is not supported (following the behaviour of
1439 DC CVAP itself if the system does not define a point of persistence).
1441 config ARM64_RAS_EXTN
1442 bool "Enable support for RAS CPU Extensions"
1445 CPUs that support the Reliability, Availability and Serviceability
1446 (RAS) Extensions, part of ARMv8.2 are able to track faults and
1447 errors, classify them and report them to software.
1449 On CPUs with these extensions system software can use additional
1450 barriers to determine if faults are pending and read the
1451 classification from a new set of registers.
1453 Selecting this feature will allow the kernel to use these barriers
1454 and access the new registers if the system supports the extension.
1455 Platform RAS features may additionally depend on firmware support.
1458 bool "Enable support for Common Not Private (CNP) translations"
1460 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
1462 Common Not Private (CNP) allows translation table entries to
1463 be shared between different PEs in the same inner shareable
1464 domain, so the hardware can use this fact to optimise the
1465 caching of such entries in the TLB.
1467 Selecting this option allows the CNP feature to be detected
1468 at runtime, and does not affect PEs that do not implement
1473 menu "ARMv8.3 architectural features"
1475 config ARM64_PTR_AUTH
1476 bool "Enable support for pointer authentication"
1478 depends on (CC_HAS_SIGN_RETURN_ADDRESS || CC_HAS_BRANCH_PROT_PAC_RET) && AS_HAS_PAC
1479 # Modern compilers insert a .note.gnu.property section note for PAC
1480 # which is only understood by binutils starting with version 2.33.1.
1481 depends on LD_IS_LLD || LD_VERSION >= 233010000 || (CC_IS_GCC && GCC_VERSION < 90100)
1482 depends on !CC_IS_CLANG || AS_HAS_CFI_NEGATE_RA_STATE
1483 depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_REGS)
1485 Pointer authentication (part of the ARMv8.3 Extensions) provides
1486 instructions for signing and authenticating pointers against secret
1487 keys, which can be used to mitigate Return Oriented Programming (ROP)
1490 This option enables these instructions at EL0 (i.e. for userspace).
1491 Choosing this option will cause the kernel to initialise secret keys
1492 for each process at exec() time, with these keys being
1493 context-switched along with the process.
1495 If the compiler supports the -mbranch-protection or
1496 -msign-return-address flag (e.g. GCC 7 or later), then this option
1497 will also cause the kernel itself to be compiled with return address
1498 protection. In this case, and if the target hardware is known to
1499 support pointer authentication, then CONFIG_STACKPROTECTOR can be
1500 disabled with minimal loss of protection.
1502 The feature is detected at runtime. If the feature is not present in
1503 hardware it will not be advertised to userspace/KVM guest nor will it
1506 If the feature is present on the boot CPU but not on a late CPU, then
1507 the late CPU will be parked. Also, if the boot CPU does not have
1508 address auth and the late CPU has then the late CPU will still boot
1509 but with the feature disabled. On such a system, this option should
1512 This feature works with FUNCTION_GRAPH_TRACER option only if
1513 DYNAMIC_FTRACE_WITH_REGS is enabled.
1515 config CC_HAS_BRANCH_PROT_PAC_RET
1516 # GCC 9 or later, clang 8 or later
1517 def_bool $(cc-option,-mbranch-protection=pac-ret+leaf)
1519 config CC_HAS_SIGN_RETURN_ADDRESS
1521 def_bool $(cc-option,-msign-return-address=all)
1524 def_bool $(cc-option,-Wa$(comma)-march=armv8.3-a)
1526 config AS_HAS_CFI_NEGATE_RA_STATE
1527 def_bool $(as-instr,.cfi_startproc\n.cfi_negate_ra_state\n.cfi_endproc\n)
1531 menu "ARMv8.4 architectural features"
1533 config ARM64_AMU_EXTN
1534 bool "Enable support for the Activity Monitors Unit CPU extension"
1537 The activity monitors extension is an optional extension introduced
1538 by the ARMv8.4 CPU architecture. This enables support for version 1
1539 of the activity monitors architecture, AMUv1.
1541 To enable the use of this extension on CPUs that implement it, say Y.
1543 Note that for architectural reasons, firmware _must_ implement AMU
1544 support when running on CPUs that present the activity monitors
1545 extension. The required support is present in:
1546 * Version 1.5 and later of the ARM Trusted Firmware
1548 For kernels that have this configuration enabled but boot with broken
1549 firmware, you may need to say N here until the firmware is fixed.
1550 Otherwise you may experience firmware panics or lockups when
1551 accessing the counter registers. Even if you are not observing these
1552 symptoms, the values returned by the register reads might not
1553 correctly reflect reality. Most commonly, the value read will be 0,
1554 indicating that the counter is not enabled.
1556 config AS_HAS_ARMV8_4
1557 def_bool $(cc-option,-Wa$(comma)-march=armv8.4-a)
1559 config ARM64_TLB_RANGE
1560 bool "Enable support for tlbi range feature"
1562 depends on AS_HAS_ARMV8_4
1564 ARMv8.4-TLBI provides TLBI invalidation instruction that apply to a
1565 range of input addresses.
1567 The feature introduces new assembly instructions, and they were
1568 support when binutils >= 2.30.
1572 menu "ARMv8.5 architectural features"
1575 bool "Branch Target Identification support"
1578 Branch Target Identification (part of the ARMv8.5 Extensions)
1579 provides a mechanism to limit the set of locations to which computed
1580 branch instructions such as BR or BLR can jump.
1582 To make use of BTI on CPUs that support it, say Y.
1584 BTI is intended to provide complementary protection to other control
1585 flow integrity protection mechanisms, such as the Pointer
1586 authentication mechanism provided as part of the ARMv8.3 Extensions.
1587 For this reason, it does not make sense to enable this option without
1588 also enabling support for pointer authentication. Thus, when
1589 enabling this option you should also select ARM64_PTR_AUTH=y.
1591 Userspace binaries must also be specifically compiled to make use of
1592 this mechanism. If you say N here or the hardware does not support
1593 BTI, such binaries can still run, but you get no additional
1594 enforcement of branch destinations.
1596 config ARM64_BTI_KERNEL
1597 bool "Use Branch Target Identification for kernel"
1599 depends on ARM64_BTI
1600 depends on ARM64_PTR_AUTH
1601 depends on CC_HAS_BRANCH_PROT_PAC_RET_BTI
1602 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94697
1603 depends on !CC_IS_GCC || GCC_VERSION >= 100100
1604 depends on !(CC_IS_CLANG && GCOV_KERNEL)
1605 depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_REGS)
1607 Build the kernel with Branch Target Identification annotations
1608 and enable enforcement of this for kernel code. When this option
1609 is enabled and the system supports BTI all kernel code including
1610 modular code must have BTI enabled.
1612 config CC_HAS_BRANCH_PROT_PAC_RET_BTI
1613 # GCC 9 or later, clang 8 or later
1614 def_bool $(cc-option,-mbranch-protection=pac-ret+leaf+bti)
1617 bool "Enable support for E0PD"
1620 E0PD (part of the ARMv8.5 extensions) allows us to ensure
1621 that EL0 accesses made via TTBR1 always fault in constant time,
1622 providing similar benefits to KASLR as those provided by KPTI, but
1623 with lower overhead and without disrupting legitimate access to
1624 kernel memory such as SPE.
1626 This option enables E0PD for TTBR1 where available.
1629 bool "Enable support for random number generation"
1632 Random number generation (part of the ARMv8.5 Extensions)
1633 provides a high bandwidth, cryptographically secure
1634 hardware random number generator.
1636 config ARM64_AS_HAS_MTE
1637 # Initial support for MTE went in binutils 2.32.0, checked with
1638 # ".arch armv8.5-a+memtag" below. However, this was incomplete
1639 # as a late addition to the final architecture spec (LDGM/STGM)
1640 # is only supported in the newer 2.32.x and 2.33 binutils
1641 # versions, hence the extra "stgm" instruction check below.
1642 def_bool $(as-instr,.arch armv8.5-a+memtag\nstgm xzr$(comma)[x0])
1645 bool "Memory Tagging Extension support"
1647 depends on ARM64_AS_HAS_MTE && ARM64_TAGGED_ADDR_ABI
1648 select ARCH_USES_HIGH_VMA_FLAGS
1650 Memory Tagging (part of the ARMv8.5 Extensions) provides
1651 architectural support for run-time, always-on detection of
1652 various classes of memory error to aid with software debugging
1653 to eliminate vulnerabilities arising from memory-unsafe
1656 This option enables the support for the Memory Tagging
1657 Extension at EL0 (i.e. for userspace).
1659 Selecting this option allows the feature to be detected at
1660 runtime. Any secondary CPU not implementing this feature will
1661 not be allowed a late bring-up.
1663 Userspace binaries that want to use this feature must
1664 explicitly opt in. The mechanism for the userspace is
1667 Documentation/arm64/memory-tagging-extension.rst.
1672 bool "ARM Scalable Vector Extension support"
1674 depends on !KVM || ARM64_VHE
1676 The Scalable Vector Extension (SVE) is an extension to the AArch64
1677 execution state which complements and extends the SIMD functionality
1678 of the base architecture to support much larger vectors and to enable
1679 additional vectorisation opportunities.
1681 To enable use of this extension on CPUs that implement it, say Y.
1683 On CPUs that support the SVE2 extensions, this option will enable
1686 Note that for architectural reasons, firmware _must_ implement SVE
1687 support when running on SVE capable hardware. The required support
1690 * version 1.5 and later of the ARM Trusted Firmware
1691 * the AArch64 boot wrapper since commit 5e1261e08abf
1692 ("bootwrapper: SVE: Enable SVE for EL2 and below").
1694 For other firmware implementations, consult the firmware documentation
1697 If you need the kernel to boot on SVE-capable hardware with broken
1698 firmware, you may need to say N here until you get your firmware
1699 fixed. Otherwise, you may experience firmware panics or lockups when
1700 booting the kernel. If unsure and you are not observing these
1701 symptoms, you should assume that it is safe to say Y.
1703 CPUs that support SVE are architecturally required to support the
1704 Virtualization Host Extensions (VHE), so the kernel makes no
1705 provision for supporting SVE alongside KVM without VHE enabled.
1706 Thus, you will need to enable CONFIG_ARM64_VHE if you want to support
1707 KVM in the same kernel image.
1709 config ARM64_MODULE_PLTS
1710 bool "Use PLTs to allow module memory to spill over into vmalloc area"
1712 select HAVE_MOD_ARCH_SPECIFIC
1714 Allocate PLTs when loading modules so that jumps and calls whose
1715 targets are too far away for their relative offsets to be encoded
1716 in the instructions themselves can be bounced via veneers in the
1717 module's PLT. This allows modules to be allocated in the generic
1718 vmalloc area after the dedicated module memory area has been
1721 When running with address space randomization (KASLR), the module
1722 region itself may be too far away for ordinary relative jumps and
1723 calls, and so in that case, module PLTs are required and cannot be
1726 Specific errata workaround(s) might also force module PLTs to be
1727 enabled (ARM64_ERRATUM_843419).
1729 config ARM64_PSEUDO_NMI
1730 bool "Support for NMI-like interrupts"
1733 Adds support for mimicking Non-Maskable Interrupts through the use of
1734 GIC interrupt priority. This support requires version 3 or later of
1737 This high priority configuration for interrupts needs to be
1738 explicitly enabled by setting the kernel parameter
1739 "irqchip.gicv3_pseudo_nmi" to 1.
1744 config ARM64_DEBUG_PRIORITY_MASKING
1745 bool "Debug interrupt priority masking"
1747 This adds runtime checks to functions enabling/disabling
1748 interrupts when using priority masking. The additional checks verify
1749 the validity of ICC_PMR_EL1 when calling concerned functions.
1755 bool "Build a relocatable kernel image" if EXPERT
1756 select ARCH_HAS_RELR
1759 This builds the kernel as a Position Independent Executable (PIE),
1760 which retains all relocation metadata required to relocate the
1761 kernel binary at runtime to a different virtual address than the
1762 address it was linked at.
1763 Since AArch64 uses the RELA relocation format, this requires a
1764 relocation pass at runtime even if the kernel is loaded at the
1765 same address it was linked at.
1767 config RANDOMIZE_BASE
1768 bool "Randomize the address of the kernel image"
1769 select ARM64_MODULE_PLTS if MODULES
1772 Randomizes the virtual address at which the kernel image is
1773 loaded, as a security feature that deters exploit attempts
1774 relying on knowledge of the location of kernel internals.
1776 It is the bootloader's job to provide entropy, by passing a
1777 random u64 value in /chosen/kaslr-seed at kernel entry.
1779 When booting via the UEFI stub, it will invoke the firmware's
1780 EFI_RNG_PROTOCOL implementation (if available) to supply entropy
1781 to the kernel proper. In addition, it will randomise the physical
1782 location of the kernel Image as well.
1786 config RANDOMIZE_MODULE_REGION_FULL
1787 bool "Randomize the module region over a 4 GB range"
1788 depends on RANDOMIZE_BASE
1791 Randomizes the location of the module region inside a 4 GB window
1792 covering the core kernel. This way, it is less likely for modules
1793 to leak information about the location of core kernel data structures
1794 but it does imply that function calls between modules and the core
1795 kernel will need to be resolved via veneers in the module PLT.
1797 When this option is not set, the module region will be randomized over
1798 a limited range that contains the [_stext, _etext] interval of the
1799 core kernel, so branch relocations are always in range.
1801 config CC_HAVE_STACKPROTECTOR_SYSREG
1802 def_bool $(cc-option,-mstack-protector-guard=sysreg -mstack-protector-guard-reg=sp_el0 -mstack-protector-guard-offset=0)
1804 config STACKPROTECTOR_PER_TASK
1806 depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_SYSREG
1812 config ARM64_ACPI_PARKING_PROTOCOL
1813 bool "Enable support for the ARM64 ACPI parking protocol"
1816 Enable support for the ARM64 ACPI parking protocol. If disabled
1817 the kernel will not allow booting through the ARM64 ACPI parking
1818 protocol even if the corresponding data is present in the ACPI
1822 string "Default kernel command string"
1825 Provide a set of default command-line options at build time by
1826 entering them here. As a minimum, you should specify the the
1827 root device (e.g. root=/dev/nfs).
1829 config CMDLINE_FORCE
1830 bool "Always use the default kernel command string"
1831 depends on CMDLINE != ""
1833 Always use the default kernel command string, even if the boot
1834 loader passes other arguments to the kernel.
1835 This is useful if you cannot or don't want to change the
1836 command-line options your boot loader passes to the kernel.
1842 bool "UEFI runtime support"
1843 depends on OF && !CPU_BIG_ENDIAN
1844 depends on KERNEL_MODE_NEON
1845 select ARCH_SUPPORTS_ACPI
1848 select EFI_PARAMS_FROM_FDT
1849 select EFI_RUNTIME_WRAPPERS
1851 select EFI_GENERIC_STUB
1854 This option provides support for runtime services provided
1855 by UEFI firmware (such as non-volatile variables, realtime
1856 clock, and platform reset). A UEFI stub is also provided to
1857 allow the kernel to be booted as an EFI application. This
1858 is only useful on systems that have UEFI firmware.
1861 bool "Enable support for SMBIOS (DMI) tables"
1865 This enables SMBIOS/DMI feature for systems.
1867 This option is only useful on systems that have UEFI firmware.
1868 However, even with this option, the resultant kernel should
1869 continue to boot on existing non-UEFI platforms.
1873 config SYSVIPC_COMPAT
1875 depends on COMPAT && SYSVIPC
1877 config ARCH_ENABLE_HUGEPAGE_MIGRATION
1879 depends on HUGETLB_PAGE && MIGRATION
1881 config ARCH_ENABLE_THP_MIGRATION
1883 depends on TRANSPARENT_HUGEPAGE
1885 menu "Power management options"
1887 source "kernel/power/Kconfig"
1889 config ARCH_HIBERNATION_POSSIBLE
1893 config ARCH_HIBERNATION_HEADER
1895 depends on HIBERNATION
1897 config ARCH_SUSPEND_POSSIBLE
1902 menu "CPU Power Management"
1904 source "drivers/cpuidle/Kconfig"
1906 source "drivers/cpufreq/Kconfig"
1910 source "drivers/firmware/Kconfig"
1912 source "drivers/acpi/Kconfig"
1914 source "arch/arm64/kvm/Kconfig"
1917 source "arch/arm64/crypto/Kconfig"