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_DMA_PREP_COHERENT
17 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
18 select ARCH_HAS_FAST_MULTIPLIER
19 select ARCH_HAS_FORTIFY_SOURCE
20 select ARCH_HAS_GCOV_PROFILE_ALL
21 select ARCH_HAS_GIGANTIC_PAGE
23 select ARCH_HAS_KEEPINITRD
24 select ARCH_HAS_MEMBARRIER_SYNC_CORE
25 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
26 select ARCH_HAS_PTE_DEVMAP
27 select ARCH_HAS_PTE_SPECIAL
28 select ARCH_HAS_SETUP_DMA_OPS
29 select ARCH_HAS_SET_DIRECT_MAP
30 select ARCH_HAS_SET_MEMORY
32 select ARCH_HAS_STRICT_KERNEL_RWX
33 select ARCH_HAS_STRICT_MODULE_RWX
34 select ARCH_HAS_SYNC_DMA_FOR_DEVICE
35 select ARCH_HAS_SYNC_DMA_FOR_CPU
36 select ARCH_HAS_SYSCALL_WRAPPER
37 select ARCH_HAS_TEARDOWN_DMA_OPS if IOMMU_SUPPORT
38 select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
39 select ARCH_HAVE_ELF_PROT
40 select ARCH_HAVE_NMI_SAFE_CMPXCHG
41 select ARCH_INLINE_READ_LOCK if !PREEMPTION
42 select ARCH_INLINE_READ_LOCK_BH if !PREEMPTION
43 select ARCH_INLINE_READ_LOCK_IRQ if !PREEMPTION
44 select ARCH_INLINE_READ_LOCK_IRQSAVE if !PREEMPTION
45 select ARCH_INLINE_READ_UNLOCK if !PREEMPTION
46 select ARCH_INLINE_READ_UNLOCK_BH if !PREEMPTION
47 select ARCH_INLINE_READ_UNLOCK_IRQ if !PREEMPTION
48 select ARCH_INLINE_READ_UNLOCK_IRQRESTORE if !PREEMPTION
49 select ARCH_INLINE_WRITE_LOCK if !PREEMPTION
50 select ARCH_INLINE_WRITE_LOCK_BH if !PREEMPTION
51 select ARCH_INLINE_WRITE_LOCK_IRQ if !PREEMPTION
52 select ARCH_INLINE_WRITE_LOCK_IRQSAVE if !PREEMPTION
53 select ARCH_INLINE_WRITE_UNLOCK if !PREEMPTION
54 select ARCH_INLINE_WRITE_UNLOCK_BH if !PREEMPTION
55 select ARCH_INLINE_WRITE_UNLOCK_IRQ if !PREEMPTION
56 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE if !PREEMPTION
57 select ARCH_INLINE_SPIN_TRYLOCK if !PREEMPTION
58 select ARCH_INLINE_SPIN_TRYLOCK_BH if !PREEMPTION
59 select ARCH_INLINE_SPIN_LOCK if !PREEMPTION
60 select ARCH_INLINE_SPIN_LOCK_BH if !PREEMPTION
61 select ARCH_INLINE_SPIN_LOCK_IRQ if !PREEMPTION
62 select ARCH_INLINE_SPIN_LOCK_IRQSAVE if !PREEMPTION
63 select ARCH_INLINE_SPIN_UNLOCK if !PREEMPTION
64 select ARCH_INLINE_SPIN_UNLOCK_BH if !PREEMPTION
65 select ARCH_INLINE_SPIN_UNLOCK_IRQ if !PREEMPTION
66 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPTION
67 select ARCH_KEEP_MEMBLOCK
68 select ARCH_USE_CMPXCHG_LOCKREF
69 select ARCH_USE_GNU_PROPERTY
70 select ARCH_USE_QUEUED_RWLOCKS
71 select ARCH_USE_QUEUED_SPINLOCKS
72 select ARCH_USE_SYM_ANNOTATIONS
73 select ARCH_SUPPORTS_DEBUG_PAGEALLOC
74 select ARCH_SUPPORTS_MEMORY_FAILURE
75 select ARCH_SUPPORTS_SHADOW_CALL_STACK if CC_HAVE_SHADOW_CALL_STACK
76 select ARCH_SUPPORTS_LTO_CLANG if CPU_LITTLE_ENDIAN
77 select ARCH_SUPPORTS_LTO_CLANG_THIN
78 select ARCH_SUPPORTS_ATOMIC_RMW
79 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && (GCC_VERSION >= 50000 || CC_IS_CLANG)
80 select ARCH_SUPPORTS_NUMA_BALANCING
81 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT
82 select ARCH_WANT_DEFAULT_BPF_JIT
83 select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
84 select ARCH_WANT_FRAME_POINTERS
85 select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
86 select ARCH_WANT_LD_ORPHAN_WARN
87 select ARCH_HAS_UBSAN_SANITIZE_ALL
91 select AUDIT_ARCH_COMPAT_GENERIC
92 select ARM_GIC_V2M if PCI
94 select ARM_GIC_V3_ITS if PCI
96 select BUILDTIME_TABLE_SORT
97 select CLONE_BACKWARDS
99 select CPU_PM if (SUSPEND || CPU_IDLE)
101 select DCACHE_WORD_ACCESS
102 select DMA_DIRECT_REMAP
105 select GENERIC_ALLOCATOR
106 select GENERIC_ARCH_TOPOLOGY
107 select GENERIC_CLOCKEVENTS_BROADCAST
108 select GENERIC_CPU_AUTOPROBE
109 select GENERIC_CPU_VULNERABILITIES
110 select GENERIC_EARLY_IOREMAP
111 select GENERIC_IDLE_POLL_SETUP
112 select GENERIC_IRQ_IPI
113 select GENERIC_IRQ_MULTI_HANDLER
114 select GENERIC_IRQ_PROBE
115 select GENERIC_IRQ_SHOW
116 select GENERIC_IRQ_SHOW_LEVEL
117 select GENERIC_LIB_DEVMEM_IS_ALLOWED
118 select GENERIC_PCI_IOMAP
119 select GENERIC_PTDUMP
120 select GENERIC_SCHED_CLOCK
121 select GENERIC_SMP_IDLE_THREAD
122 select GENERIC_STRNCPY_FROM_USER
123 select GENERIC_STRNLEN_USER
124 select GENERIC_TIME_VSYSCALL
125 select GENERIC_GETTIMEOFDAY
126 select GENERIC_VDSO_TIME_NS
127 select HANDLE_DOMAIN_IRQ
128 select HARDIRQS_SW_RESEND
132 select HAVE_ACPI_APEI if (ACPI && EFI)
133 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
134 select HAVE_ARCH_AUDITSYSCALL
135 select HAVE_ARCH_BITREVERSE
136 select HAVE_ARCH_COMPILER_H
137 select HAVE_ARCH_HUGE_VMAP
138 select HAVE_ARCH_JUMP_LABEL
139 select HAVE_ARCH_JUMP_LABEL_RELATIVE
140 select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48)
141 select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN
142 select HAVE_ARCH_KASAN_HW_TAGS if (HAVE_ARCH_KASAN && ARM64_MTE)
143 select HAVE_ARCH_KFENCE
144 select HAVE_ARCH_KGDB
145 select HAVE_ARCH_MMAP_RND_BITS
146 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
147 select HAVE_ARCH_PFN_VALID
148 select HAVE_ARCH_PREL32_RELOCATIONS
149 select HAVE_ARCH_SECCOMP_FILTER
150 select HAVE_ARCH_STACKLEAK
151 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
152 select HAVE_ARCH_TRACEHOOK
153 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
154 select HAVE_ARCH_VMAP_STACK
155 select HAVE_ARM_SMCCC
156 select HAVE_ASM_MODVERSIONS
158 select HAVE_C_RECORDMCOUNT
159 select HAVE_CMPXCHG_DOUBLE
160 select HAVE_CMPXCHG_LOCAL
161 select HAVE_CONTEXT_TRACKING
162 select HAVE_DEBUG_BUGVERBOSE
163 select HAVE_DEBUG_KMEMLEAK
164 select HAVE_DMA_CONTIGUOUS
165 select HAVE_DYNAMIC_FTRACE
166 select HAVE_DYNAMIC_FTRACE_WITH_REGS \
167 if $(cc-option,-fpatchable-function-entry=2)
168 select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY \
169 if DYNAMIC_FTRACE_WITH_REGS
170 select HAVE_EFFICIENT_UNALIGNED_ACCESS
172 select HAVE_FTRACE_MCOUNT_RECORD
173 select HAVE_FUNCTION_TRACER
174 select HAVE_FUNCTION_ERROR_INJECTION
175 select HAVE_FUNCTION_GRAPH_TRACER
176 select HAVE_GCC_PLUGINS
177 select HAVE_HW_BREAKPOINT if PERF_EVENTS
178 select HAVE_IRQ_TIME_ACCOUNTING
180 select HAVE_PATA_PLATFORM
181 select HAVE_PERF_EVENTS
182 select HAVE_PERF_REGS
183 select HAVE_PERF_USER_STACK_DUMP
184 select HAVE_REGS_AND_STACK_ACCESS_API
185 select HAVE_FUNCTION_ARG_ACCESS_API
186 select HAVE_FUTEX_CMPXCHG if FUTEX
187 select MMU_GATHER_RCU_TABLE_FREE
189 select HAVE_STACKPROTECTOR
190 select HAVE_SYSCALL_TRACEPOINTS
192 select HAVE_KRETPROBES
193 select HAVE_GENERIC_VDSO
194 select IOMMU_DMA if IOMMU_SUPPORT
196 select IRQ_FORCED_THREADING
197 select MODULES_USE_ELF_RELA
198 select NEED_DMA_MAP_STATE
199 select NEED_SG_DMA_LENGTH
201 select OF_EARLY_FLATTREE
202 select PCI_DOMAINS_GENERIC if PCI
203 select PCI_ECAM if (ACPI && PCI)
204 select PCI_SYSCALL if PCI
209 select SYSCTL_EXCEPTION_TRACE
210 select THREAD_INFO_IN_TASK
212 ARM 64-bit (AArch64) Linux support.
220 config ARM64_PAGE_SHIFT
222 default 16 if ARM64_64K_PAGES
223 default 14 if ARM64_16K_PAGES
226 config ARM64_CONT_PTE_SHIFT
228 default 5 if ARM64_64K_PAGES
229 default 7 if ARM64_16K_PAGES
232 config ARM64_CONT_PMD_SHIFT
234 default 5 if ARM64_64K_PAGES
235 default 5 if ARM64_16K_PAGES
238 config ARCH_MMAP_RND_BITS_MIN
239 default 14 if ARM64_64K_PAGES
240 default 16 if ARM64_16K_PAGES
243 # max bits determined by the following formula:
244 # VA_BITS - PAGE_SHIFT - 3
245 config ARCH_MMAP_RND_BITS_MAX
246 default 19 if ARM64_VA_BITS=36
247 default 24 if ARM64_VA_BITS=39
248 default 27 if ARM64_VA_BITS=42
249 default 30 if ARM64_VA_BITS=47
250 default 29 if ARM64_VA_BITS=48 && ARM64_64K_PAGES
251 default 31 if ARM64_VA_BITS=48 && ARM64_16K_PAGES
252 default 33 if ARM64_VA_BITS=48
253 default 14 if ARM64_64K_PAGES
254 default 16 if ARM64_16K_PAGES
257 config ARCH_MMAP_RND_COMPAT_BITS_MIN
258 default 7 if ARM64_64K_PAGES
259 default 9 if ARM64_16K_PAGES
262 config ARCH_MMAP_RND_COMPAT_BITS_MAX
268 config STACKTRACE_SUPPORT
271 config ILLEGAL_POINTER_VALUE
273 default 0xdead000000000000
275 config LOCKDEP_SUPPORT
278 config TRACE_IRQFLAGS_SUPPORT
285 config GENERIC_BUG_RELATIVE_POINTERS
287 depends on GENERIC_BUG
289 config GENERIC_HWEIGHT
295 config GENERIC_CALIBRATE_DELAY
299 bool "Support DMA zone" if EXPERT
303 bool "Support DMA32 zone" if EXPERT
306 config ARCH_ENABLE_MEMORY_HOTPLUG
309 config ARCH_ENABLE_MEMORY_HOTREMOVE
315 config KERNEL_MODE_NEON
318 config FIX_EARLYCON_MEM
321 config PGTABLE_LEVELS
323 default 2 if ARM64_16K_PAGES && ARM64_VA_BITS_36
324 default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42
325 default 3 if ARM64_64K_PAGES && (ARM64_VA_BITS_48 || ARM64_VA_BITS_52)
326 default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39
327 default 3 if ARM64_16K_PAGES && ARM64_VA_BITS_47
328 default 4 if !ARM64_64K_PAGES && ARM64_VA_BITS_48
330 config ARCH_SUPPORTS_UPROBES
333 config ARCH_PROC_KCORE_TEXT
336 config BROKEN_GAS_INST
337 def_bool !$(as-instr,1:\n.inst 0\n.rept . - 1b\n\nnop\n.endr\n)
339 config KASAN_SHADOW_OFFSET
341 depends on KASAN_GENERIC || KASAN_SW_TAGS
342 default 0xdfff800000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && !KASAN_SW_TAGS
343 default 0xdfffc00000000000 if ARM64_VA_BITS_47 && !KASAN_SW_TAGS
344 default 0xdffffe0000000000 if ARM64_VA_BITS_42 && !KASAN_SW_TAGS
345 default 0xdfffffc000000000 if ARM64_VA_BITS_39 && !KASAN_SW_TAGS
346 default 0xdffffff800000000 if ARM64_VA_BITS_36 && !KASAN_SW_TAGS
347 default 0xefff800000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && KASAN_SW_TAGS
348 default 0xefffc00000000000 if ARM64_VA_BITS_47 && KASAN_SW_TAGS
349 default 0xeffffe0000000000 if ARM64_VA_BITS_42 && KASAN_SW_TAGS
350 default 0xefffffc000000000 if ARM64_VA_BITS_39 && KASAN_SW_TAGS
351 default 0xeffffff800000000 if ARM64_VA_BITS_36 && KASAN_SW_TAGS
352 default 0xffffffffffffffff
354 source "arch/arm64/Kconfig.platforms"
356 menu "Kernel Features"
358 menu "ARM errata workarounds via the alternatives framework"
360 config ARM64_WORKAROUND_CLEAN_CACHE
363 config ARM64_ERRATUM_826319
364 bool "Cortex-A53: 826319: System might deadlock if a write cannot complete until read data is accepted"
366 select ARM64_WORKAROUND_CLEAN_CACHE
368 This option adds an alternative code sequence to work around ARM
369 erratum 826319 on Cortex-A53 parts up to r0p2 with an AMBA 4 ACE or
370 AXI master interface and an L2 cache.
372 If a Cortex-A53 uses an AMBA AXI4 ACE interface to other processors
373 and is unable to accept a certain write via this interface, it will
374 not progress on read data presented on the read data channel and the
377 The workaround promotes data cache clean instructions to
378 data cache clean-and-invalidate.
379 Please note that this does not necessarily enable the workaround,
380 as it depends on the alternative framework, which will only patch
381 the kernel if an affected CPU is detected.
385 config ARM64_ERRATUM_827319
386 bool "Cortex-A53: 827319: Data cache clean instructions might cause overlapping transactions to the interconnect"
388 select ARM64_WORKAROUND_CLEAN_CACHE
390 This option adds an alternative code sequence to work around ARM
391 erratum 827319 on Cortex-A53 parts up to r0p2 with an AMBA 5 CHI
392 master interface and an L2 cache.
394 Under certain conditions this erratum can cause a clean line eviction
395 to occur at the same time as another transaction to the same address
396 on the AMBA 5 CHI interface, which can cause data corruption if the
397 interconnect reorders the two transactions.
399 The workaround promotes data cache clean instructions to
400 data cache clean-and-invalidate.
401 Please note that this does not necessarily enable the workaround,
402 as it depends on the alternative framework, which will only patch
403 the kernel if an affected CPU is detected.
407 config ARM64_ERRATUM_824069
408 bool "Cortex-A53: 824069: Cache line might not be marked as clean after a CleanShared snoop"
410 select ARM64_WORKAROUND_CLEAN_CACHE
412 This option adds an alternative code sequence to work around ARM
413 erratum 824069 on Cortex-A53 parts up to r0p2 when it is connected
414 to a coherent interconnect.
416 If a Cortex-A53 processor is executing a store or prefetch for
417 write instruction at the same time as a processor in another
418 cluster is executing a cache maintenance operation to the same
419 address, then this erratum might cause a clean cache line to be
420 incorrectly marked as dirty.
422 The workaround promotes data cache clean instructions to
423 data cache clean-and-invalidate.
424 Please note that this option does not necessarily enable the
425 workaround, as it depends on the alternative framework, which will
426 only patch the kernel if an affected CPU is detected.
430 config ARM64_ERRATUM_819472
431 bool "Cortex-A53: 819472: Store exclusive instructions might cause data corruption"
433 select ARM64_WORKAROUND_CLEAN_CACHE
435 This option adds an alternative code sequence to work around ARM
436 erratum 819472 on Cortex-A53 parts up to r0p1 with an L2 cache
437 present when it is connected to a coherent interconnect.
439 If the processor is executing a load and store exclusive sequence at
440 the same time as a processor in another cluster is executing a cache
441 maintenance operation to the same address, then this erratum might
442 cause data corruption.
444 The workaround promotes data cache clean instructions to
445 data cache clean-and-invalidate.
446 Please note that this does not necessarily enable the workaround,
447 as it depends on the alternative framework, which will only patch
448 the kernel if an affected CPU is detected.
452 config ARM64_ERRATUM_832075
453 bool "Cortex-A57: 832075: possible deadlock on mixing exclusive memory accesses with device loads"
456 This option adds an alternative code sequence to work around ARM
457 erratum 832075 on Cortex-A57 parts up to r1p2.
459 Affected Cortex-A57 parts might deadlock when exclusive load/store
460 instructions to Write-Back memory are mixed with Device loads.
462 The workaround is to promote device loads to use Load-Acquire
464 Please note that this does not necessarily enable the workaround,
465 as it depends on the alternative framework, which will only patch
466 the kernel if an affected CPU is detected.
470 config ARM64_ERRATUM_834220
471 bool "Cortex-A57: 834220: Stage 2 translation fault might be incorrectly reported in presence of a Stage 1 fault"
475 This option adds an alternative code sequence to work around ARM
476 erratum 834220 on Cortex-A57 parts up to r1p2.
478 Affected Cortex-A57 parts might report a Stage 2 translation
479 fault as the result of a Stage 1 fault for load crossing a
480 page boundary when there is a permission or device memory
481 alignment fault at Stage 1 and a translation fault at Stage 2.
483 The workaround is to verify that the Stage 1 translation
484 doesn't generate a fault before handling the Stage 2 fault.
485 Please note that this does not necessarily enable the workaround,
486 as it depends on the alternative framework, which will only patch
487 the kernel if an affected CPU is detected.
491 config ARM64_ERRATUM_845719
492 bool "Cortex-A53: 845719: a load might read incorrect data"
496 This option adds an alternative code sequence to work around ARM
497 erratum 845719 on Cortex-A53 parts up to r0p4.
499 When running a compat (AArch32) userspace on an affected Cortex-A53
500 part, a load at EL0 from a virtual address that matches the bottom 32
501 bits of the virtual address used by a recent load at (AArch64) EL1
502 might return incorrect data.
504 The workaround is to write the contextidr_el1 register on exception
505 return to a 32-bit task.
506 Please note that this does not necessarily enable the workaround,
507 as it depends on the alternative framework, which will only patch
508 the kernel if an affected CPU is detected.
512 config ARM64_ERRATUM_843419
513 bool "Cortex-A53: 843419: A load or store might access an incorrect address"
515 select ARM64_MODULE_PLTS if MODULES
517 This option links the kernel with '--fix-cortex-a53-843419' and
518 enables PLT support to replace certain ADRP instructions, which can
519 cause subsequent memory accesses to use an incorrect address on
520 Cortex-A53 parts up to r0p4.
524 config ARM64_ERRATUM_1024718
525 bool "Cortex-A55: 1024718: Update of DBM/AP bits without break before make might result in incorrect update"
528 This option adds a workaround for ARM Cortex-A55 Erratum 1024718.
530 Affected Cortex-A55 cores (all revisions) could cause incorrect
531 update of the hardware dirty bit when the DBM/AP bits are updated
532 without a break-before-make. The workaround is to disable the usage
533 of hardware DBM locally on the affected cores. CPUs not affected by
534 this erratum will continue to use the feature.
538 config ARM64_ERRATUM_1418040
539 bool "Cortex-A76/Neoverse-N1: MRC read following MRRC read of specific Generic Timer in AArch32 might give incorrect result"
543 This option adds a workaround for ARM Cortex-A76/Neoverse-N1
544 errata 1188873 and 1418040.
546 Affected Cortex-A76/Neoverse-N1 cores (r0p0 to r3p1) could
547 cause register corruption when accessing the timer registers
548 from AArch32 userspace.
552 config ARM64_WORKAROUND_SPECULATIVE_AT
555 config ARM64_ERRATUM_1165522
556 bool "Cortex-A76: 1165522: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
558 select ARM64_WORKAROUND_SPECULATIVE_AT
560 This option adds a workaround for ARM Cortex-A76 erratum 1165522.
562 Affected Cortex-A76 cores (r0p0, r1p0, r2p0) could end-up with
563 corrupted TLBs by speculating an AT instruction during a guest
568 config ARM64_ERRATUM_1319367
569 bool "Cortex-A57/A72: 1319537: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
571 select ARM64_WORKAROUND_SPECULATIVE_AT
573 This option adds work arounds for ARM Cortex-A57 erratum 1319537
574 and A72 erratum 1319367
576 Cortex-A57 and A72 cores could end-up with corrupted TLBs by
577 speculating an AT instruction during a guest context switch.
581 config ARM64_ERRATUM_1530923
582 bool "Cortex-A55: 1530923: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
584 select ARM64_WORKAROUND_SPECULATIVE_AT
586 This option adds a workaround for ARM Cortex-A55 erratum 1530923.
588 Affected Cortex-A55 cores (r0p0, r0p1, r1p0, r2p0) could end-up with
589 corrupted TLBs by speculating an AT instruction during a guest
594 config ARM64_WORKAROUND_REPEAT_TLBI
597 config ARM64_ERRATUM_1286807
598 bool "Cortex-A76: Modification of the translation table for a virtual address might lead to read-after-read ordering violation"
600 select ARM64_WORKAROUND_REPEAT_TLBI
602 This option adds a workaround for ARM Cortex-A76 erratum 1286807.
604 On the affected Cortex-A76 cores (r0p0 to r3p0), if a virtual
605 address for a cacheable mapping of a location is being
606 accessed by a core while another core is remapping the virtual
607 address to a new physical page using the recommended
608 break-before-make sequence, then under very rare circumstances
609 TLBI+DSB completes before a read using the translation being
610 invalidated has been observed by other observers. The
611 workaround repeats the TLBI+DSB operation.
613 config ARM64_ERRATUM_1463225
614 bool "Cortex-A76: Software Step might prevent interrupt recognition"
617 This option adds a workaround for Arm Cortex-A76 erratum 1463225.
619 On the affected Cortex-A76 cores (r0p0 to r3p1), software stepping
620 of a system call instruction (SVC) can prevent recognition of
621 subsequent interrupts when software stepping is disabled in the
622 exception handler of the system call and either kernel debugging
623 is enabled or VHE is in use.
625 Work around the erratum by triggering a dummy step exception
626 when handling a system call from a task that is being stepped
627 in a VHE configuration of the kernel.
631 config ARM64_ERRATUM_1542419
632 bool "Neoverse-N1: workaround mis-ordering of instruction fetches"
635 This option adds a workaround for ARM Neoverse-N1 erratum
638 Affected Neoverse-N1 cores could execute a stale instruction when
639 modified by another CPU. The workaround depends on a firmware
642 Workaround the issue by hiding the DIC feature from EL0. This
643 forces user-space to perform cache maintenance.
647 config ARM64_ERRATUM_1508412
648 bool "Cortex-A77: 1508412: workaround deadlock on sequence of NC/Device load and store exclusive or PAR read"
651 This option adds a workaround for Arm Cortex-A77 erratum 1508412.
653 Affected Cortex-A77 cores (r0p0, r1p0) could deadlock on a sequence
654 of a store-exclusive or read of PAR_EL1 and a load with device or
655 non-cacheable memory attributes. The workaround depends on a firmware
658 KVM guests must also have the workaround implemented or they can
661 Work around the issue by inserting DMB SY barriers around PAR_EL1
662 register reads and warning KVM users. The DMB barrier is sufficient
663 to prevent a speculative PAR_EL1 read.
667 config CAVIUM_ERRATUM_22375
668 bool "Cavium erratum 22375, 24313"
671 Enable workaround for errata 22375 and 24313.
673 This implements two gicv3-its errata workarounds for ThunderX. Both
674 with a small impact affecting only ITS table allocation.
676 erratum 22375: only alloc 8MB table size
677 erratum 24313: ignore memory access type
679 The fixes are in ITS initialization and basically ignore memory access
680 type and table size provided by the TYPER and BASER registers.
684 config CAVIUM_ERRATUM_23144
685 bool "Cavium erratum 23144: ITS SYNC hang on dual socket system"
689 ITS SYNC command hang for cross node io and collections/cpu mapping.
693 config CAVIUM_ERRATUM_23154
694 bool "Cavium erratum 23154: Access to ICC_IAR1_EL1 is not sync'ed"
697 The gicv3 of ThunderX requires a modified version for
698 reading the IAR status to ensure data synchronization
699 (access to icc_iar1_el1 is not sync'ed before and after).
703 config CAVIUM_ERRATUM_27456
704 bool "Cavium erratum 27456: Broadcast TLBI instructions may cause icache corruption"
707 On ThunderX T88 pass 1.x through 2.1 parts, broadcast TLBI
708 instructions may cause the icache to become corrupted if it
709 contains data for a non-current ASID. The fix is to
710 invalidate the icache when changing the mm context.
714 config CAVIUM_ERRATUM_30115
715 bool "Cavium erratum 30115: Guest may disable interrupts in host"
718 On ThunderX T88 pass 1.x through 2.2, T81 pass 1.0 through
719 1.2, and T83 Pass 1.0, KVM guest execution may disable
720 interrupts in host. Trapping both GICv3 group-0 and group-1
721 accesses sidesteps the issue.
725 config CAVIUM_TX2_ERRATUM_219
726 bool "Cavium ThunderX2 erratum 219: PRFM between TTBR change and ISB fails"
729 On Cavium ThunderX2, a load, store or prefetch instruction between a
730 TTBR update and the corresponding context synchronizing operation can
731 cause a spurious Data Abort to be delivered to any hardware thread in
734 Work around the issue by avoiding the problematic code sequence and
735 trapping KVM guest TTBRx_EL1 writes to EL2 when SMT is enabled. The
736 trap handler performs the corresponding register access, skips the
737 instruction and ensures context synchronization by virtue of the
742 config FUJITSU_ERRATUM_010001
743 bool "Fujitsu-A64FX erratum E#010001: Undefined fault may occur wrongly"
746 This option adds a workaround for Fujitsu-A64FX erratum E#010001.
747 On some variants of the Fujitsu-A64FX cores ver(1.0, 1.1), memory
748 accesses may cause undefined fault (Data abort, DFSC=0b111111).
749 This fault occurs under a specific hardware condition when a
750 load/store instruction performs an address translation using:
751 case-1 TTBR0_EL1 with TCR_EL1.NFD0 == 1.
752 case-2 TTBR0_EL2 with TCR_EL2.NFD0 == 1.
753 case-3 TTBR1_EL1 with TCR_EL1.NFD1 == 1.
754 case-4 TTBR1_EL2 with TCR_EL2.NFD1 == 1.
756 The workaround is to ensure these bits are clear in TCR_ELx.
757 The workaround only affects the Fujitsu-A64FX.
761 config HISILICON_ERRATUM_161600802
762 bool "Hip07 161600802: Erroneous redistributor VLPI base"
765 The HiSilicon Hip07 SoC uses the wrong redistributor base
766 when issued ITS commands such as VMOVP and VMAPP, and requires
767 a 128kB offset to be applied to the target address in this commands.
771 config QCOM_FALKOR_ERRATUM_1003
772 bool "Falkor E1003: Incorrect translation due to ASID change"
775 On Falkor v1, an incorrect ASID may be cached in the TLB when ASID
776 and BADDR are changed together in TTBRx_EL1. Since we keep the ASID
777 in TTBR1_EL1, this situation only occurs in the entry trampoline and
778 then only for entries in the walk cache, since the leaf translation
779 is unchanged. Work around the erratum by invalidating the walk cache
780 entries for the trampoline before entering the kernel proper.
782 config QCOM_FALKOR_ERRATUM_1009
783 bool "Falkor E1009: Prematurely complete a DSB after a TLBI"
785 select ARM64_WORKAROUND_REPEAT_TLBI
787 On Falkor v1, the CPU may prematurely complete a DSB following a
788 TLBI xxIS invalidate maintenance operation. Repeat the TLBI operation
789 one more time to fix the issue.
793 config QCOM_QDF2400_ERRATUM_0065
794 bool "QDF2400 E0065: Incorrect GITS_TYPER.ITT_Entry_size"
797 On Qualcomm Datacenter Technologies QDF2400 SoC, ITS hardware reports
798 ITE size incorrectly. The GITS_TYPER.ITT_Entry_size field should have
799 been indicated as 16Bytes (0xf), not 8Bytes (0x7).
803 config QCOM_FALKOR_ERRATUM_E1041
804 bool "Falkor E1041: Speculative instruction fetches might cause errant memory access"
807 Falkor CPU may speculatively fetch instructions from an improper
808 memory location when MMU translation is changed from SCTLR_ELn[M]=1
809 to SCTLR_ELn[M]=0. Prefix an ISB instruction to fix the problem.
813 config SOCIONEXT_SYNQUACER_PREITS
814 bool "Socionext Synquacer: Workaround for GICv3 pre-ITS"
817 Socionext Synquacer SoCs implement a separate h/w block to generate
818 MSI doorbell writes with non-zero values for the device ID.
827 default ARM64_4K_PAGES
829 Page size (translation granule) configuration.
831 config ARM64_4K_PAGES
834 This feature enables 4KB pages support.
836 config ARM64_16K_PAGES
839 The system will use 16KB pages support. AArch32 emulation
840 requires applications compiled with 16K (or a multiple of 16K)
843 config ARM64_64K_PAGES
846 This feature enables 64KB pages support (4KB by default)
847 allowing only two levels of page tables and faster TLB
848 look-up. AArch32 emulation requires applications compiled
849 with 64K aligned segments.
854 prompt "Virtual address space size"
855 default ARM64_VA_BITS_39 if ARM64_4K_PAGES
856 default ARM64_VA_BITS_47 if ARM64_16K_PAGES
857 default ARM64_VA_BITS_42 if ARM64_64K_PAGES
859 Allows choosing one of multiple possible virtual address
860 space sizes. The level of translation table is determined by
861 a combination of page size and virtual address space size.
863 config ARM64_VA_BITS_36
864 bool "36-bit" if EXPERT
865 depends on ARM64_16K_PAGES
867 config ARM64_VA_BITS_39
869 depends on ARM64_4K_PAGES
871 config ARM64_VA_BITS_42
873 depends on ARM64_64K_PAGES
875 config ARM64_VA_BITS_47
877 depends on ARM64_16K_PAGES
879 config ARM64_VA_BITS_48
882 config ARM64_VA_BITS_52
884 depends on ARM64_64K_PAGES && (ARM64_PAN || !ARM64_SW_TTBR0_PAN)
886 Enable 52-bit virtual addressing for userspace when explicitly
887 requested via a hint to mmap(). The kernel will also use 52-bit
888 virtual addresses for its own mappings (provided HW support for
889 this feature is available, otherwise it reverts to 48-bit).
891 NOTE: Enabling 52-bit virtual addressing in conjunction with
892 ARMv8.3 Pointer Authentication will result in the PAC being
893 reduced from 7 bits to 3 bits, which may have a significant
894 impact on its susceptibility to brute-force attacks.
896 If unsure, select 48-bit virtual addressing instead.
900 config ARM64_FORCE_52BIT
901 bool "Force 52-bit virtual addresses for userspace"
902 depends on ARM64_VA_BITS_52 && EXPERT
904 For systems with 52-bit userspace VAs enabled, the kernel will attempt
905 to maintain compatibility with older software by providing 48-bit VAs
906 unless a hint is supplied to mmap.
908 This configuration option disables the 48-bit compatibility logic, and
909 forces all userspace addresses to be 52-bit on HW that supports it. One
910 should only enable this configuration option for stress testing userspace
911 memory management code. If unsure say N here.
915 default 36 if ARM64_VA_BITS_36
916 default 39 if ARM64_VA_BITS_39
917 default 42 if ARM64_VA_BITS_42
918 default 47 if ARM64_VA_BITS_47
919 default 48 if ARM64_VA_BITS_48
920 default 52 if ARM64_VA_BITS_52
923 prompt "Physical address space size"
924 default ARM64_PA_BITS_48
926 Choose the maximum physical address range that the kernel will
929 config ARM64_PA_BITS_48
932 config ARM64_PA_BITS_52
933 bool "52-bit (ARMv8.2)"
934 depends on ARM64_64K_PAGES
935 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
937 Enable support for a 52-bit physical address space, introduced as
938 part of the ARMv8.2-LPA extension.
940 With this enabled, the kernel will also continue to work on CPUs that
941 do not support ARMv8.2-LPA, but with some added memory overhead (and
942 minor performance overhead).
948 default 48 if ARM64_PA_BITS_48
949 default 52 if ARM64_PA_BITS_52
953 default CPU_LITTLE_ENDIAN
955 Select the endianness of data accesses performed by the CPU. Userspace
956 applications will need to be compiled and linked for the endianness
957 that is selected here.
959 config CPU_BIG_ENDIAN
960 bool "Build big-endian kernel"
961 depends on !LD_IS_LLD || LLD_VERSION >= 130000
963 Say Y if you plan on running a kernel with a big-endian userspace.
965 config CPU_LITTLE_ENDIAN
966 bool "Build little-endian kernel"
968 Say Y if you plan on running a kernel with a little-endian userspace.
969 This is usually the case for distributions targeting arm64.
974 bool "Multi-core scheduler support"
976 Multi-core scheduler support improves the CPU scheduler's decision
977 making when dealing with multi-core CPU chips at a cost of slightly
978 increased overhead in some places. If unsure say N here.
981 bool "SMT scheduler support"
983 Improves the CPU scheduler's decision making when dealing with
984 MultiThreading at a cost of slightly increased overhead in some
985 places. If unsure say N here.
988 int "Maximum number of CPUs (2-4096)"
993 bool "Support for hot-pluggable CPUs"
994 select GENERIC_IRQ_MIGRATION
996 Say Y here to experiment with turning CPUs off and on. CPUs
997 can be controlled through /sys/devices/system/cpu.
999 # Common NUMA Features
1001 bool "NUMA Memory Allocation and Scheduler Support"
1002 select GENERIC_ARCH_NUMA
1003 select ACPI_NUMA if ACPI
1006 Enable NUMA (Non-Uniform Memory Access) support.
1008 The kernel will try to allocate memory used by a CPU on the
1009 local memory of the CPU and add some more
1010 NUMA awareness to the kernel.
1013 int "Maximum NUMA Nodes (as a power of 2)"
1016 depends on NEED_MULTIPLE_NODES
1018 Specify the maximum number of NUMA Nodes available on the target
1019 system. Increases memory reserved to accommodate various tables.
1021 config USE_PERCPU_NUMA_NODE_ID
1025 config HAVE_SETUP_PER_CPU_AREA
1029 config NEED_PER_CPU_EMBED_FIRST_CHUNK
1033 config HOLES_IN_ZONE
1036 source "kernel/Kconfig.hz"
1038 config ARCH_SPARSEMEM_ENABLE
1040 select SPARSEMEM_VMEMMAP_ENABLE
1042 config ARCH_SPARSEMEM_DEFAULT
1043 def_bool ARCH_SPARSEMEM_ENABLE
1045 config ARCH_SELECT_MEMORY_MODEL
1046 def_bool ARCH_SPARSEMEM_ENABLE
1048 config ARCH_FLATMEM_ENABLE
1051 config HW_PERF_EVENTS
1055 config SYS_SUPPORTS_HUGETLBFS
1058 config ARCH_WANT_HUGE_PMD_SHARE
1060 config ARCH_HAS_CACHE_LINE_SIZE
1063 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
1064 def_bool y if PGTABLE_LEVELS > 2
1066 # Supported by clang >= 7.0
1067 config CC_HAVE_SHADOW_CALL_STACK
1068 def_bool $(cc-option, -fsanitize=shadow-call-stack -ffixed-x18)
1071 bool "Enable paravirtualization code"
1073 This changes the kernel so it can modify itself when it is run
1074 under a hypervisor, potentially improving performance significantly
1075 over full virtualization.
1077 config PARAVIRT_TIME_ACCOUNTING
1078 bool "Paravirtual steal time accounting"
1081 Select this option to enable fine granularity task steal time
1082 accounting. Time spent executing other tasks in parallel with
1083 the current vCPU is discounted from the vCPU power. To account for
1084 that, there can be a small performance impact.
1086 If in doubt, say N here.
1089 depends on PM_SLEEP_SMP
1091 bool "kexec system call"
1093 kexec is a system call that implements the ability to shutdown your
1094 current kernel, and to start another kernel. It is like a reboot
1095 but it is independent of the system firmware. And like a reboot
1096 you can start any kernel with it, not just Linux.
1099 bool "kexec file based system call"
1102 This is new version of kexec system call. This system call is
1103 file based and takes file descriptors as system call argument
1104 for kernel and initramfs as opposed to list of segments as
1105 accepted by previous system call.
1108 bool "Verify kernel signature during kexec_file_load() syscall"
1109 depends on KEXEC_FILE
1111 Select this option to verify a signature with loaded kernel
1112 image. If configured, any attempt of loading a image without
1113 valid signature will fail.
1115 In addition to that option, you need to enable signature
1116 verification for the corresponding kernel image type being
1117 loaded in order for this to work.
1119 config KEXEC_IMAGE_VERIFY_SIG
1120 bool "Enable Image signature verification support"
1122 depends on KEXEC_SIG
1123 depends on EFI && SIGNED_PE_FILE_VERIFICATION
1125 Enable Image signature verification support.
1127 comment "Support for PE file signature verification disabled"
1128 depends on KEXEC_SIG
1129 depends on !EFI || !SIGNED_PE_FILE_VERIFICATION
1132 bool "Build kdump crash kernel"
1134 Generate crash dump after being started by kexec. This should
1135 be normally only set in special crash dump kernels which are
1136 loaded in the main kernel with kexec-tools into a specially
1137 reserved region and then later executed after a crash by
1140 For more details see Documentation/admin-guide/kdump/kdump.rst
1144 depends on HIBERNATION
1151 bool "Xen guest support on ARM64"
1152 depends on ARM64 && OF
1156 Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64.
1158 config FORCE_MAX_ZONEORDER
1160 default "14" if (ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE)
1161 default "12" if (ARM64_16K_PAGES && TRANSPARENT_HUGEPAGE)
1164 The kernel memory allocator divides physically contiguous memory
1165 blocks into "zones", where each zone is a power of two number of
1166 pages. This option selects the largest power of two that the kernel
1167 keeps in the memory allocator. If you need to allocate very large
1168 blocks of physically contiguous memory, then you may need to
1169 increase this value.
1171 This config option is actually maximum order plus one. For example,
1172 a value of 11 means that the largest free memory block is 2^10 pages.
1174 We make sure that we can allocate upto a HugePage size for each configuration.
1176 MAX_ORDER = (PMD_SHIFT - PAGE_SHIFT) + 1 => PAGE_SHIFT - 2
1178 However for 4K, we choose a higher default value, 11 as opposed to 10, giving us
1179 4M allocations matching the default size used by generic code.
1181 config UNMAP_KERNEL_AT_EL0
1182 bool "Unmap kernel when running in userspace (aka \"KAISER\")" if EXPERT
1185 Speculation attacks against some high-performance processors can
1186 be used to bypass MMU permission checks and leak kernel data to
1187 userspace. This can be defended against by unmapping the kernel
1188 when running in userspace, mapping it back in on exception entry
1189 via a trampoline page in the vector table.
1193 config RODATA_FULL_DEFAULT_ENABLED
1194 bool "Apply r/o permissions of VM areas also to their linear aliases"
1197 Apply read-only attributes of VM areas to the linear alias of
1198 the backing pages as well. This prevents code or read-only data
1199 from being modified (inadvertently or intentionally) via another
1200 mapping of the same memory page. This additional enhancement can
1201 be turned off at runtime by passing rodata=[off|on] (and turned on
1202 with rodata=full if this option is set to 'n')
1204 This requires the linear region to be mapped down to pages,
1205 which may adversely affect performance in some cases.
1207 config ARM64_SW_TTBR0_PAN
1208 bool "Emulate Privileged Access Never using TTBR0_EL1 switching"
1210 Enabling this option prevents the kernel from accessing
1211 user-space memory directly by pointing TTBR0_EL1 to a reserved
1212 zeroed area and reserved ASID. The user access routines
1213 restore the valid TTBR0_EL1 temporarily.
1215 config ARM64_TAGGED_ADDR_ABI
1216 bool "Enable the tagged user addresses syscall ABI"
1219 When this option is enabled, user applications can opt in to a
1220 relaxed ABI via prctl() allowing tagged addresses to be passed
1221 to system calls as pointer arguments. For details, see
1222 Documentation/arm64/tagged-address-abi.rst.
1225 bool "Kernel support for 32-bit EL0"
1226 depends on ARM64_4K_PAGES || EXPERT
1228 select OLD_SIGSUSPEND3
1229 select COMPAT_OLD_SIGACTION
1231 This option enables support for a 32-bit EL0 running under a 64-bit
1232 kernel at EL1. AArch32-specific components such as system calls,
1233 the user helper functions, VFP support and the ptrace interface are
1234 handled appropriately by the kernel.
1236 If you use a page size other than 4KB (i.e, 16KB or 64KB), please be aware
1237 that you will only be able to execute AArch32 binaries that were compiled
1238 with page size aligned segments.
1240 If you want to execute 32-bit userspace applications, say Y.
1244 config KUSER_HELPERS
1245 bool "Enable kuser helpers page for 32-bit applications"
1248 Warning: disabling this option may break 32-bit user programs.
1250 Provide kuser helpers to compat tasks. The kernel provides
1251 helper code to userspace in read only form at a fixed location
1252 to allow userspace to be independent of the CPU type fitted to
1253 the system. This permits binaries to be run on ARMv4 through
1254 to ARMv8 without modification.
1256 See Documentation/arm/kernel_user_helpers.rst for details.
1258 However, the fixed address nature of these helpers can be used
1259 by ROP (return orientated programming) authors when creating
1262 If all of the binaries and libraries which run on your platform
1263 are built specifically for your platform, and make no use of
1264 these helpers, then you can turn this option off to hinder
1265 such exploits. However, in that case, if a binary or library
1266 relying on those helpers is run, it will not function correctly.
1268 Say N here only if you are absolutely certain that you do not
1269 need these helpers; otherwise, the safe option is to say Y.
1272 bool "Enable vDSO for 32-bit applications"
1273 depends on !CPU_BIG_ENDIAN && "$(CROSS_COMPILE_COMPAT)" != ""
1274 select GENERIC_COMPAT_VDSO
1277 Place in the process address space of 32-bit applications an
1278 ELF shared object providing fast implementations of gettimeofday
1281 You must have a 32-bit build of glibc 2.22 or later for programs
1282 to seamlessly take advantage of this.
1284 config THUMB2_COMPAT_VDSO
1285 bool "Compile the 32-bit vDSO for Thumb-2 mode" if EXPERT
1286 depends on COMPAT_VDSO
1289 Compile the compat vDSO with '-mthumb -fomit-frame-pointer' if y,
1290 otherwise with '-marm'.
1292 menuconfig ARMV8_DEPRECATED
1293 bool "Emulate deprecated/obsolete ARMv8 instructions"
1296 Legacy software support may require certain instructions
1297 that have been deprecated or obsoleted in the architecture.
1299 Enable this config to enable selective emulation of these
1306 config SWP_EMULATION
1307 bool "Emulate SWP/SWPB instructions"
1309 ARMv8 obsoletes the use of A32 SWP/SWPB instructions such that
1310 they are always undefined. Say Y here to enable software
1311 emulation of these instructions for userspace using LDXR/STXR.
1312 This feature can be controlled at runtime with the abi.swp
1313 sysctl which is disabled by default.
1315 In some older versions of glibc [<=2.8] SWP is used during futex
1316 trylock() operations with the assumption that the code will not
1317 be preempted. This invalid assumption may be more likely to fail
1318 with SWP emulation enabled, leading to deadlock of the user
1321 NOTE: when accessing uncached shared regions, LDXR/STXR rely
1322 on an external transaction monitoring block called a global
1323 monitor to maintain update atomicity. If your system does not
1324 implement a global monitor, this option can cause programs that
1325 perform SWP operations to uncached memory to deadlock.
1329 config CP15_BARRIER_EMULATION
1330 bool "Emulate CP15 Barrier instructions"
1332 The CP15 barrier instructions - CP15ISB, CP15DSB, and
1333 CP15DMB - are deprecated in ARMv8 (and ARMv7). It is
1334 strongly recommended to use the ISB, DSB, and DMB
1335 instructions instead.
1337 Say Y here to enable software emulation of these
1338 instructions for AArch32 userspace code. When this option is
1339 enabled, CP15 barrier usage is traced which can help
1340 identify software that needs updating. This feature can be
1341 controlled at runtime with the abi.cp15_barrier sysctl.
1345 config SETEND_EMULATION
1346 bool "Emulate SETEND instruction"
1348 The SETEND instruction alters the data-endianness of the
1349 AArch32 EL0, and is deprecated in ARMv8.
1351 Say Y here to enable software emulation of the instruction
1352 for AArch32 userspace code. This feature can be controlled
1353 at runtime with the abi.setend sysctl.
1355 Note: All the cpus on the system must have mixed endian support at EL0
1356 for this feature to be enabled. If a new CPU - which doesn't support mixed
1357 endian - is hotplugged in after this feature has been enabled, there could
1358 be unexpected results in the applications.
1365 menu "ARMv8.1 architectural features"
1367 config ARM64_HW_AFDBM
1368 bool "Support for hardware updates of the Access and Dirty page flags"
1371 The ARMv8.1 architecture extensions introduce support for
1372 hardware updates of the access and dirty information in page
1373 table entries. When enabled in TCR_EL1 (HA and HD bits) on
1374 capable processors, accesses to pages with PTE_AF cleared will
1375 set this bit instead of raising an access flag fault.
1376 Similarly, writes to read-only pages with the DBM bit set will
1377 clear the read-only bit (AP[2]) instead of raising a
1380 Kernels built with this configuration option enabled continue
1381 to work on pre-ARMv8.1 hardware and the performance impact is
1382 minimal. If unsure, say Y.
1385 bool "Enable support for Privileged Access Never (PAN)"
1388 Privileged Access Never (PAN; part of the ARMv8.1 Extensions)
1389 prevents the kernel or hypervisor from accessing user-space (EL0)
1392 Choosing this option will cause any unprotected (not using
1393 copy_to_user et al) memory access to fail with a permission fault.
1395 The feature is detected at runtime, and will remain as a 'nop'
1396 instruction if the cpu does not implement the feature.
1399 def_bool $(as-instr,.arch_extension rcpc)
1401 config ARM64_LSE_ATOMICS
1403 default ARM64_USE_LSE_ATOMICS
1404 depends on $(as-instr,.arch_extension lse)
1406 config ARM64_USE_LSE_ATOMICS
1407 bool "Atomic instructions"
1408 depends on JUMP_LABEL
1411 As part of the Large System Extensions, ARMv8.1 introduces new
1412 atomic instructions that are designed specifically to scale in
1415 Say Y here to make use of these instructions for the in-kernel
1416 atomic routines. This incurs a small overhead on CPUs that do
1417 not support these instructions and requires the kernel to be
1418 built with binutils >= 2.25 in order for the new instructions
1422 bool "Enable support for Virtualization Host Extensions (VHE)"
1425 Virtualization Host Extensions (VHE) allow the kernel to run
1426 directly at EL2 (instead of EL1) on processors that support
1427 it. This leads to better performance for KVM, as they reduce
1428 the cost of the world switch.
1430 Selecting this option allows the VHE feature to be detected
1431 at runtime, and does not affect processors that do not
1432 implement this feature.
1436 menu "ARMv8.2 architectural features"
1439 bool "Enable support for persistent memory"
1440 select ARCH_HAS_PMEM_API
1441 select ARCH_HAS_UACCESS_FLUSHCACHE
1443 Say Y to enable support for the persistent memory API based on the
1444 ARMv8.2 DCPoP feature.
1446 The feature is detected at runtime, and the kernel will use DC CVAC
1447 operations if DC CVAP is not supported (following the behaviour of
1448 DC CVAP itself if the system does not define a point of persistence).
1450 config ARM64_RAS_EXTN
1451 bool "Enable support for RAS CPU Extensions"
1454 CPUs that support the Reliability, Availability and Serviceability
1455 (RAS) Extensions, part of ARMv8.2 are able to track faults and
1456 errors, classify them and report them to software.
1458 On CPUs with these extensions system software can use additional
1459 barriers to determine if faults are pending and read the
1460 classification from a new set of registers.
1462 Selecting this feature will allow the kernel to use these barriers
1463 and access the new registers if the system supports the extension.
1464 Platform RAS features may additionally depend on firmware support.
1467 bool "Enable support for Common Not Private (CNP) translations"
1469 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
1471 Common Not Private (CNP) allows translation table entries to
1472 be shared between different PEs in the same inner shareable
1473 domain, so the hardware can use this fact to optimise the
1474 caching of such entries in the TLB.
1476 Selecting this option allows the CNP feature to be detected
1477 at runtime, and does not affect PEs that do not implement
1482 menu "ARMv8.3 architectural features"
1484 config ARM64_PTR_AUTH
1485 bool "Enable support for pointer authentication"
1487 depends on (CC_HAS_SIGN_RETURN_ADDRESS || CC_HAS_BRANCH_PROT_PAC_RET) && AS_HAS_PAC
1488 # Modern compilers insert a .note.gnu.property section note for PAC
1489 # which is only understood by binutils starting with version 2.33.1.
1490 depends on LD_IS_LLD || LD_VERSION >= 23301 || (CC_IS_GCC && GCC_VERSION < 90100)
1491 depends on !CC_IS_CLANG || AS_HAS_CFI_NEGATE_RA_STATE
1492 depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_REGS)
1494 Pointer authentication (part of the ARMv8.3 Extensions) provides
1495 instructions for signing and authenticating pointers against secret
1496 keys, which can be used to mitigate Return Oriented Programming (ROP)
1499 This option enables these instructions at EL0 (i.e. for userspace).
1500 Choosing this option will cause the kernel to initialise secret keys
1501 for each process at exec() time, with these keys being
1502 context-switched along with the process.
1504 If the compiler supports the -mbranch-protection or
1505 -msign-return-address flag (e.g. GCC 7 or later), then this option
1506 will also cause the kernel itself to be compiled with return address
1507 protection. In this case, and if the target hardware is known to
1508 support pointer authentication, then CONFIG_STACKPROTECTOR can be
1509 disabled with minimal loss of protection.
1511 The feature is detected at runtime. If the feature is not present in
1512 hardware it will not be advertised to userspace/KVM guest nor will it
1515 If the feature is present on the boot CPU but not on a late CPU, then
1516 the late CPU will be parked. Also, if the boot CPU does not have
1517 address auth and the late CPU has then the late CPU will still boot
1518 but with the feature disabled. On such a system, this option should
1521 This feature works with FUNCTION_GRAPH_TRACER option only if
1522 DYNAMIC_FTRACE_WITH_REGS is enabled.
1524 config CC_HAS_BRANCH_PROT_PAC_RET
1525 # GCC 9 or later, clang 8 or later
1526 def_bool $(cc-option,-mbranch-protection=pac-ret+leaf)
1528 config CC_HAS_SIGN_RETURN_ADDRESS
1530 def_bool $(cc-option,-msign-return-address=all)
1533 def_bool $(cc-option,-Wa$(comma)-march=armv8.3-a)
1535 config AS_HAS_CFI_NEGATE_RA_STATE
1536 def_bool $(as-instr,.cfi_startproc\n.cfi_negate_ra_state\n.cfi_endproc\n)
1540 menu "ARMv8.4 architectural features"
1542 config ARM64_AMU_EXTN
1543 bool "Enable support for the Activity Monitors Unit CPU extension"
1546 The activity monitors extension is an optional extension introduced
1547 by the ARMv8.4 CPU architecture. This enables support for version 1
1548 of the activity monitors architecture, AMUv1.
1550 To enable the use of this extension on CPUs that implement it, say Y.
1552 Note that for architectural reasons, firmware _must_ implement AMU
1553 support when running on CPUs that present the activity monitors
1554 extension. The required support is present in:
1555 * Version 1.5 and later of the ARM Trusted Firmware
1557 For kernels that have this configuration enabled but boot with broken
1558 firmware, you may need to say N here until the firmware is fixed.
1559 Otherwise you may experience firmware panics or lockups when
1560 accessing the counter registers. Even if you are not observing these
1561 symptoms, the values returned by the register reads might not
1562 correctly reflect reality. Most commonly, the value read will be 0,
1563 indicating that the counter is not enabled.
1565 config AS_HAS_ARMV8_4
1566 def_bool $(cc-option,-Wa$(comma)-march=armv8.4-a)
1568 config ARM64_TLB_RANGE
1569 bool "Enable support for tlbi range feature"
1571 depends on AS_HAS_ARMV8_4
1573 ARMv8.4-TLBI provides TLBI invalidation instruction that apply to a
1574 range of input addresses.
1576 The feature introduces new assembly instructions, and they were
1577 support when binutils >= 2.30.
1581 menu "ARMv8.5 architectural features"
1583 config AS_HAS_ARMV8_5
1584 def_bool $(cc-option,-Wa$(comma)-march=armv8.5-a)
1587 bool "Branch Target Identification support"
1590 Branch Target Identification (part of the ARMv8.5 Extensions)
1591 provides a mechanism to limit the set of locations to which computed
1592 branch instructions such as BR or BLR can jump.
1594 To make use of BTI on CPUs that support it, say Y.
1596 BTI is intended to provide complementary protection to other control
1597 flow integrity protection mechanisms, such as the Pointer
1598 authentication mechanism provided as part of the ARMv8.3 Extensions.
1599 For this reason, it does not make sense to enable this option without
1600 also enabling support for pointer authentication. Thus, when
1601 enabling this option you should also select ARM64_PTR_AUTH=y.
1603 Userspace binaries must also be specifically compiled to make use of
1604 this mechanism. If you say N here or the hardware does not support
1605 BTI, such binaries can still run, but you get no additional
1606 enforcement of branch destinations.
1608 config ARM64_BTI_KERNEL
1609 bool "Use Branch Target Identification for kernel"
1611 depends on ARM64_BTI
1612 depends on ARM64_PTR_AUTH
1613 depends on CC_HAS_BRANCH_PROT_PAC_RET_BTI
1614 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94697
1615 depends on !CC_IS_GCC || GCC_VERSION >= 100100
1616 depends on !(CC_IS_CLANG && GCOV_KERNEL)
1617 depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_REGS)
1619 Build the kernel with Branch Target Identification annotations
1620 and enable enforcement of this for kernel code. When this option
1621 is enabled and the system supports BTI all kernel code including
1622 modular code must have BTI enabled.
1624 config CC_HAS_BRANCH_PROT_PAC_RET_BTI
1625 # GCC 9 or later, clang 8 or later
1626 def_bool $(cc-option,-mbranch-protection=pac-ret+leaf+bti)
1629 bool "Enable support for E0PD"
1632 E0PD (part of the ARMv8.5 extensions) allows us to ensure
1633 that EL0 accesses made via TTBR1 always fault in constant time,
1634 providing similar benefits to KASLR as those provided by KPTI, but
1635 with lower overhead and without disrupting legitimate access to
1636 kernel memory such as SPE.
1638 This option enables E0PD for TTBR1 where available.
1641 bool "Enable support for random number generation"
1644 Random number generation (part of the ARMv8.5 Extensions)
1645 provides a high bandwidth, cryptographically secure
1646 hardware random number generator.
1648 config ARM64_AS_HAS_MTE
1649 # Initial support for MTE went in binutils 2.32.0, checked with
1650 # ".arch armv8.5-a+memtag" below. However, this was incomplete
1651 # as a late addition to the final architecture spec (LDGM/STGM)
1652 # is only supported in the newer 2.32.x and 2.33 binutils
1653 # versions, hence the extra "stgm" instruction check below.
1654 def_bool $(as-instr,.arch armv8.5-a+memtag\nstgm xzr$(comma)[x0])
1657 bool "Memory Tagging Extension support"
1659 depends on ARM64_AS_HAS_MTE && ARM64_TAGGED_ADDR_ABI
1660 depends on AS_HAS_ARMV8_5
1661 # Required for tag checking in the uaccess routines
1662 depends on ARM64_PAN
1663 select ARCH_USES_HIGH_VMA_FLAGS
1665 Memory Tagging (part of the ARMv8.5 Extensions) provides
1666 architectural support for run-time, always-on detection of
1667 various classes of memory error to aid with software debugging
1668 to eliminate vulnerabilities arising from memory-unsafe
1671 This option enables the support for the Memory Tagging
1672 Extension at EL0 (i.e. for userspace).
1674 Selecting this option allows the feature to be detected at
1675 runtime. Any secondary CPU not implementing this feature will
1676 not be allowed a late bring-up.
1678 Userspace binaries that want to use this feature must
1679 explicitly opt in. The mechanism for the userspace is
1682 Documentation/arm64/memory-tagging-extension.rst.
1687 bool "ARM Scalable Vector Extension support"
1689 depends on !KVM || ARM64_VHE
1691 The Scalable Vector Extension (SVE) is an extension to the AArch64
1692 execution state which complements and extends the SIMD functionality
1693 of the base architecture to support much larger vectors and to enable
1694 additional vectorisation opportunities.
1696 To enable use of this extension on CPUs that implement it, say Y.
1698 On CPUs that support the SVE2 extensions, this option will enable
1701 Note that for architectural reasons, firmware _must_ implement SVE
1702 support when running on SVE capable hardware. The required support
1705 * version 1.5 and later of the ARM Trusted Firmware
1706 * the AArch64 boot wrapper since commit 5e1261e08abf
1707 ("bootwrapper: SVE: Enable SVE for EL2 and below").
1709 For other firmware implementations, consult the firmware documentation
1712 If you need the kernel to boot on SVE-capable hardware with broken
1713 firmware, you may need to say N here until you get your firmware
1714 fixed. Otherwise, you may experience firmware panics or lockups when
1715 booting the kernel. If unsure and you are not observing these
1716 symptoms, you should assume that it is safe to say Y.
1718 CPUs that support SVE are architecturally required to support the
1719 Virtualization Host Extensions (VHE), so the kernel makes no
1720 provision for supporting SVE alongside KVM without VHE enabled.
1721 Thus, you will need to enable CONFIG_ARM64_VHE if you want to support
1722 KVM in the same kernel image.
1724 config ARM64_MODULE_PLTS
1725 bool "Use PLTs to allow module memory to spill over into vmalloc area"
1727 select HAVE_MOD_ARCH_SPECIFIC
1729 Allocate PLTs when loading modules so that jumps and calls whose
1730 targets are too far away for their relative offsets to be encoded
1731 in the instructions themselves can be bounced via veneers in the
1732 module's PLT. This allows modules to be allocated in the generic
1733 vmalloc area after the dedicated module memory area has been
1736 When running with address space randomization (KASLR), the module
1737 region itself may be too far away for ordinary relative jumps and
1738 calls, and so in that case, module PLTs are required and cannot be
1741 Specific errata workaround(s) might also force module PLTs to be
1742 enabled (ARM64_ERRATUM_843419).
1744 config ARM64_PSEUDO_NMI
1745 bool "Support for NMI-like interrupts"
1748 Adds support for mimicking Non-Maskable Interrupts through the use of
1749 GIC interrupt priority. This support requires version 3 or later of
1752 This high priority configuration for interrupts needs to be
1753 explicitly enabled by setting the kernel parameter
1754 "irqchip.gicv3_pseudo_nmi" to 1.
1759 config ARM64_DEBUG_PRIORITY_MASKING
1760 bool "Debug interrupt priority masking"
1762 This adds runtime checks to functions enabling/disabling
1763 interrupts when using priority masking. The additional checks verify
1764 the validity of ICC_PMR_EL1 when calling concerned functions.
1770 bool "Build a relocatable kernel image" if EXPERT
1771 select ARCH_HAS_RELR
1774 This builds the kernel as a Position Independent Executable (PIE),
1775 which retains all relocation metadata required to relocate the
1776 kernel binary at runtime to a different virtual address than the
1777 address it was linked at.
1778 Since AArch64 uses the RELA relocation format, this requires a
1779 relocation pass at runtime even if the kernel is loaded at the
1780 same address it was linked at.
1782 config RANDOMIZE_BASE
1783 bool "Randomize the address of the kernel image"
1784 select ARM64_MODULE_PLTS if MODULES
1787 Randomizes the virtual address at which the kernel image is
1788 loaded, as a security feature that deters exploit attempts
1789 relying on knowledge of the location of kernel internals.
1791 It is the bootloader's job to provide entropy, by passing a
1792 random u64 value in /chosen/kaslr-seed at kernel entry.
1794 When booting via the UEFI stub, it will invoke the firmware's
1795 EFI_RNG_PROTOCOL implementation (if available) to supply entropy
1796 to the kernel proper. In addition, it will randomise the physical
1797 location of the kernel Image as well.
1801 config RANDOMIZE_MODULE_REGION_FULL
1802 bool "Randomize the module region over a 4 GB range"
1803 depends on RANDOMIZE_BASE
1806 Randomizes the location of the module region inside a 4 GB window
1807 covering the core kernel. This way, it is less likely for modules
1808 to leak information about the location of core kernel data structures
1809 but it does imply that function calls between modules and the core
1810 kernel will need to be resolved via veneers in the module PLT.
1812 When this option is not set, the module region will be randomized over
1813 a limited range that contains the [_stext, _etext] interval of the
1814 core kernel, so branch relocations are always in range.
1816 config CC_HAVE_STACKPROTECTOR_SYSREG
1817 def_bool $(cc-option,-mstack-protector-guard=sysreg -mstack-protector-guard-reg=sp_el0 -mstack-protector-guard-offset=0)
1819 config STACKPROTECTOR_PER_TASK
1821 depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_SYSREG
1827 config ARM64_ACPI_PARKING_PROTOCOL
1828 bool "Enable support for the ARM64 ACPI parking protocol"
1831 Enable support for the ARM64 ACPI parking protocol. If disabled
1832 the kernel will not allow booting through the ARM64 ACPI parking
1833 protocol even if the corresponding data is present in the ACPI
1837 string "Default kernel command string"
1840 Provide a set of default command-line options at build time by
1841 entering them here. As a minimum, you should specify the the
1842 root device (e.g. root=/dev/nfs).
1845 prompt "Kernel command line type" if CMDLINE != ""
1846 default CMDLINE_FROM_BOOTLOADER
1848 Choose how the kernel will handle the provided default kernel
1849 command line string.
1851 config CMDLINE_FROM_BOOTLOADER
1852 bool "Use bootloader kernel arguments if available"
1854 Uses the command-line options passed by the boot loader. If
1855 the boot loader doesn't provide any, the default kernel command
1856 string provided in CMDLINE will be used.
1858 config CMDLINE_EXTEND
1859 bool "Extend bootloader kernel arguments"
1861 The command-line arguments provided by the boot loader will be
1862 appended to the default kernel command string.
1864 config CMDLINE_FORCE
1865 bool "Always use the default kernel command string"
1867 Always use the default kernel command string, even if the boot
1868 loader passes other arguments to the kernel.
1869 This is useful if you cannot or don't want to change the
1870 command-line options your boot loader passes to the kernel.
1878 bool "UEFI runtime support"
1879 depends on OF && !CPU_BIG_ENDIAN
1880 depends on KERNEL_MODE_NEON
1881 select ARCH_SUPPORTS_ACPI
1884 select EFI_PARAMS_FROM_FDT
1885 select EFI_RUNTIME_WRAPPERS
1887 select EFI_GENERIC_STUB
1888 imply IMA_SECURE_AND_OR_TRUSTED_BOOT
1891 This option provides support for runtime services provided
1892 by UEFI firmware (such as non-volatile variables, realtime
1893 clock, and platform reset). A UEFI stub is also provided to
1894 allow the kernel to be booted as an EFI application. This
1895 is only useful on systems that have UEFI firmware.
1898 bool "Enable support for SMBIOS (DMI) tables"
1902 This enables SMBIOS/DMI feature for systems.
1904 This option is only useful on systems that have UEFI firmware.
1905 However, even with this option, the resultant kernel should
1906 continue to boot on existing non-UEFI platforms.
1910 config SYSVIPC_COMPAT
1912 depends on COMPAT && SYSVIPC
1914 config ARCH_ENABLE_HUGEPAGE_MIGRATION
1916 depends on HUGETLB_PAGE && MIGRATION
1918 config ARCH_ENABLE_THP_MIGRATION
1920 depends on TRANSPARENT_HUGEPAGE
1922 menu "Power management options"
1924 source "kernel/power/Kconfig"
1926 config ARCH_HIBERNATION_POSSIBLE
1930 config ARCH_HIBERNATION_HEADER
1932 depends on HIBERNATION
1934 config ARCH_SUSPEND_POSSIBLE
1939 menu "CPU Power Management"
1941 source "drivers/cpuidle/Kconfig"
1943 source "drivers/cpufreq/Kconfig"
1947 source "drivers/firmware/Kconfig"
1949 source "drivers/acpi/Kconfig"
1951 source "arch/arm64/kvm/Kconfig"
1954 source "arch/arm64/crypto/Kconfig"