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_CLOCKSOURCE_DATA
13 select ARCH_HAS_DEBUG_VIRTUAL
14 select ARCH_HAS_DEVMEM_IS_ALLOWED
15 select ARCH_HAS_DMA_COHERENT_TO_PFN
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_PTE_DEVMAP
26 select ARCH_HAS_PTE_SPECIAL
27 select ARCH_HAS_SETUP_DMA_OPS
28 select ARCH_HAS_SET_DIRECT_MAP
29 select ARCH_HAS_SET_MEMORY
30 select ARCH_HAS_STRICT_KERNEL_RWX
31 select ARCH_HAS_STRICT_MODULE_RWX
32 select ARCH_HAS_SYNC_DMA_FOR_DEVICE
33 select ARCH_HAS_SYNC_DMA_FOR_CPU
34 select ARCH_HAS_SYSCALL_WRAPPER
35 select ARCH_HAS_TEARDOWN_DMA_OPS if IOMMU_SUPPORT
36 select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
37 select ARCH_HAVE_NMI_SAFE_CMPXCHG
38 select ARCH_INLINE_READ_LOCK if !PREEMPT
39 select ARCH_INLINE_READ_LOCK_BH if !PREEMPT
40 select ARCH_INLINE_READ_LOCK_IRQ if !PREEMPT
41 select ARCH_INLINE_READ_LOCK_IRQSAVE if !PREEMPT
42 select ARCH_INLINE_READ_UNLOCK if !PREEMPT
43 select ARCH_INLINE_READ_UNLOCK_BH if !PREEMPT
44 select ARCH_INLINE_READ_UNLOCK_IRQ if !PREEMPT
45 select ARCH_INLINE_READ_UNLOCK_IRQRESTORE if !PREEMPT
46 select ARCH_INLINE_WRITE_LOCK if !PREEMPT
47 select ARCH_INLINE_WRITE_LOCK_BH if !PREEMPT
48 select ARCH_INLINE_WRITE_LOCK_IRQ if !PREEMPT
49 select ARCH_INLINE_WRITE_LOCK_IRQSAVE if !PREEMPT
50 select ARCH_INLINE_WRITE_UNLOCK if !PREEMPT
51 select ARCH_INLINE_WRITE_UNLOCK_BH if !PREEMPT
52 select ARCH_INLINE_WRITE_UNLOCK_IRQ if !PREEMPT
53 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE if !PREEMPT
54 select ARCH_INLINE_SPIN_TRYLOCK if !PREEMPT
55 select ARCH_INLINE_SPIN_TRYLOCK_BH if !PREEMPT
56 select ARCH_INLINE_SPIN_LOCK if !PREEMPT
57 select ARCH_INLINE_SPIN_LOCK_BH if !PREEMPT
58 select ARCH_INLINE_SPIN_LOCK_IRQ if !PREEMPT
59 select ARCH_INLINE_SPIN_LOCK_IRQSAVE if !PREEMPT
60 select ARCH_INLINE_SPIN_UNLOCK if !PREEMPT
61 select ARCH_INLINE_SPIN_UNLOCK_BH if !PREEMPT
62 select ARCH_INLINE_SPIN_UNLOCK_IRQ if !PREEMPT
63 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPT
64 select ARCH_KEEP_MEMBLOCK
65 select ARCH_USE_CMPXCHG_LOCKREF
66 select ARCH_USE_QUEUED_RWLOCKS
67 select ARCH_USE_QUEUED_SPINLOCKS
68 select ARCH_SUPPORTS_MEMORY_FAILURE
69 select ARCH_SUPPORTS_ATOMIC_RMW
70 select ARCH_SUPPORTS_INT128 if GCC_VERSION >= 50000 || CC_IS_CLANG
71 select ARCH_SUPPORTS_NUMA_BALANCING
72 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT
73 select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
74 select ARCH_WANT_FRAME_POINTERS
75 select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
76 select ARCH_HAS_UBSAN_SANITIZE_ALL
80 select AUDIT_ARCH_COMPAT_GENERIC
81 select ARM_GIC_V2M if PCI
83 select ARM_GIC_V3_ITS if PCI
85 select BUILDTIME_EXTABLE_SORT
86 select CLONE_BACKWARDS
88 select CPU_PM if (SUSPEND || CPU_IDLE)
90 select DCACHE_WORD_ACCESS
91 select DMA_DIRECT_REMAP
94 select GENERIC_ALLOCATOR
95 select GENERIC_ARCH_TOPOLOGY
96 select GENERIC_CLOCKEVENTS
97 select GENERIC_CLOCKEVENTS_BROADCAST
98 select GENERIC_CPU_AUTOPROBE
99 select GENERIC_CPU_VULNERABILITIES
100 select GENERIC_EARLY_IOREMAP
101 select GENERIC_IDLE_POLL_SETUP
102 select GENERIC_IRQ_MULTI_HANDLER
103 select GENERIC_IRQ_PROBE
104 select GENERIC_IRQ_SHOW
105 select GENERIC_IRQ_SHOW_LEVEL
106 select GENERIC_PCI_IOMAP
107 select GENERIC_SCHED_CLOCK
108 select GENERIC_SMP_IDLE_THREAD
109 select GENERIC_STRNCPY_FROM_USER
110 select GENERIC_STRNLEN_USER
111 select GENERIC_TIME_VSYSCALL
112 select GENERIC_GETTIMEOFDAY
113 select HANDLE_DOMAIN_IRQ
114 select HARDIRQS_SW_RESEND
116 select HAVE_ACPI_APEI if (ACPI && EFI)
117 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
118 select HAVE_ARCH_AUDITSYSCALL
119 select HAVE_ARCH_BITREVERSE
120 select HAVE_ARCH_HUGE_VMAP
121 select HAVE_ARCH_JUMP_LABEL
122 select HAVE_ARCH_JUMP_LABEL_RELATIVE
123 select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48)
124 select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN
125 select HAVE_ARCH_KGDB
126 select HAVE_ARCH_MMAP_RND_BITS
127 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
128 select HAVE_ARCH_PREL32_RELOCATIONS
129 select HAVE_ARCH_SECCOMP_FILTER
130 select HAVE_ARCH_STACKLEAK
131 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
132 select HAVE_ARCH_TRACEHOOK
133 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
134 select HAVE_ARCH_VMAP_STACK
135 select HAVE_ARM_SMCCC
136 select HAVE_ASM_MODVERSIONS
138 select HAVE_C_RECORDMCOUNT
139 select HAVE_CMPXCHG_DOUBLE
140 select HAVE_CMPXCHG_LOCAL
141 select HAVE_CONTEXT_TRACKING
142 select HAVE_COPY_THREAD_TLS
143 select HAVE_DEBUG_BUGVERBOSE
144 select HAVE_DEBUG_KMEMLEAK
145 select HAVE_DMA_CONTIGUOUS
146 select HAVE_DYNAMIC_FTRACE
147 select HAVE_EFFICIENT_UNALIGNED_ACCESS
149 select HAVE_FTRACE_MCOUNT_RECORD
150 select HAVE_FUNCTION_TRACER
151 select HAVE_FUNCTION_ERROR_INJECTION
152 select HAVE_FUNCTION_GRAPH_TRACER
153 select HAVE_GCC_PLUGINS
154 select HAVE_HW_BREAKPOINT if PERF_EVENTS
155 select HAVE_IRQ_TIME_ACCOUNTING
156 select HAVE_MEMBLOCK_NODE_MAP if NUMA
158 select HAVE_PATA_PLATFORM
159 select HAVE_PERF_EVENTS
160 select HAVE_PERF_REGS
161 select HAVE_PERF_USER_STACK_DUMP
162 select HAVE_REGS_AND_STACK_ACCESS_API
163 select HAVE_FUNCTION_ARG_ACCESS_API
164 select HAVE_RCU_TABLE_FREE
166 select HAVE_STACKPROTECTOR
167 select HAVE_SYSCALL_TRACEPOINTS
169 select HAVE_KRETPROBES
170 select HAVE_GENERIC_VDSO
171 select IOMMU_DMA if IOMMU_SUPPORT
173 select IRQ_FORCED_THREADING
174 select MODULES_USE_ELF_RELA
175 select NEED_DMA_MAP_STATE
176 select NEED_SG_DMA_LENGTH
178 select OF_EARLY_FLATTREE
179 select PCI_DOMAINS_GENERIC if PCI
180 select PCI_ECAM if (ACPI && PCI)
181 select PCI_SYSCALL if PCI
186 select SYSCTL_EXCEPTION_TRACE
187 select THREAD_INFO_IN_TASK
189 ARM 64-bit (AArch64) Linux support.
197 config ARM64_PAGE_SHIFT
199 default 16 if ARM64_64K_PAGES
200 default 14 if ARM64_16K_PAGES
203 config ARM64_CONT_SHIFT
205 default 5 if ARM64_64K_PAGES
206 default 7 if ARM64_16K_PAGES
209 config ARCH_MMAP_RND_BITS_MIN
210 default 14 if ARM64_64K_PAGES
211 default 16 if ARM64_16K_PAGES
214 # max bits determined by the following formula:
215 # VA_BITS - PAGE_SHIFT - 3
216 config ARCH_MMAP_RND_BITS_MAX
217 default 19 if ARM64_VA_BITS=36
218 default 24 if ARM64_VA_BITS=39
219 default 27 if ARM64_VA_BITS=42
220 default 30 if ARM64_VA_BITS=47
221 default 29 if ARM64_VA_BITS=48 && ARM64_64K_PAGES
222 default 31 if ARM64_VA_BITS=48 && ARM64_16K_PAGES
223 default 33 if ARM64_VA_BITS=48
224 default 14 if ARM64_64K_PAGES
225 default 16 if ARM64_16K_PAGES
228 config ARCH_MMAP_RND_COMPAT_BITS_MIN
229 default 7 if ARM64_64K_PAGES
230 default 9 if ARM64_16K_PAGES
233 config ARCH_MMAP_RND_COMPAT_BITS_MAX
239 config STACKTRACE_SUPPORT
242 config ILLEGAL_POINTER_VALUE
244 default 0xdead000000000000
246 config LOCKDEP_SUPPORT
249 config TRACE_IRQFLAGS_SUPPORT
256 config GENERIC_BUG_RELATIVE_POINTERS
258 depends on GENERIC_BUG
260 config GENERIC_HWEIGHT
266 config GENERIC_CALIBRATE_DELAY
270 bool "Support DMA32 zone" if EXPERT
273 config ARCH_ENABLE_MEMORY_HOTPLUG
279 config KERNEL_MODE_NEON
282 config FIX_EARLYCON_MEM
285 config PGTABLE_LEVELS
287 default 2 if ARM64_16K_PAGES && ARM64_VA_BITS_36
288 default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42
289 default 3 if ARM64_64K_PAGES && (ARM64_VA_BITS_48 || ARM64_VA_BITS_52)
290 default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39
291 default 3 if ARM64_16K_PAGES && ARM64_VA_BITS_47
292 default 4 if !ARM64_64K_PAGES && ARM64_VA_BITS_48
294 config ARCH_SUPPORTS_UPROBES
297 config ARCH_PROC_KCORE_TEXT
300 config KASAN_SHADOW_OFFSET
303 default 0xdfffa00000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && !KASAN_SW_TAGS
304 default 0xdfffd00000000000 if ARM64_VA_BITS_47 && !KASAN_SW_TAGS
305 default 0xdffffe8000000000 if ARM64_VA_BITS_42 && !KASAN_SW_TAGS
306 default 0xdfffffd000000000 if ARM64_VA_BITS_39 && !KASAN_SW_TAGS
307 default 0xdffffffa00000000 if ARM64_VA_BITS_36 && !KASAN_SW_TAGS
308 default 0xefff900000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && KASAN_SW_TAGS
309 default 0xefffc80000000000 if ARM64_VA_BITS_47 && KASAN_SW_TAGS
310 default 0xeffffe4000000000 if ARM64_VA_BITS_42 && KASAN_SW_TAGS
311 default 0xefffffc800000000 if ARM64_VA_BITS_39 && KASAN_SW_TAGS
312 default 0xeffffff900000000 if ARM64_VA_BITS_36 && KASAN_SW_TAGS
313 default 0xffffffffffffffff
315 source "arch/arm64/Kconfig.platforms"
317 menu "Kernel Features"
319 menu "ARM errata workarounds via the alternatives framework"
321 config ARM64_WORKAROUND_CLEAN_CACHE
324 config ARM64_ERRATUM_826319
325 bool "Cortex-A53: 826319: System might deadlock if a write cannot complete until read data is accepted"
327 select ARM64_WORKAROUND_CLEAN_CACHE
329 This option adds an alternative code sequence to work around ARM
330 erratum 826319 on Cortex-A53 parts up to r0p2 with an AMBA 4 ACE or
331 AXI master interface and an L2 cache.
333 If a Cortex-A53 uses an AMBA AXI4 ACE interface to other processors
334 and is unable to accept a certain write via this interface, it will
335 not progress on read data presented on the read data channel and the
338 The workaround promotes data cache clean instructions to
339 data cache clean-and-invalidate.
340 Please note that this does not necessarily enable the workaround,
341 as it depends on the alternative framework, which will only patch
342 the kernel if an affected CPU is detected.
346 config ARM64_ERRATUM_827319
347 bool "Cortex-A53: 827319: Data cache clean instructions might cause overlapping transactions to the interconnect"
349 select ARM64_WORKAROUND_CLEAN_CACHE
351 This option adds an alternative code sequence to work around ARM
352 erratum 827319 on Cortex-A53 parts up to r0p2 with an AMBA 5 CHI
353 master interface and an L2 cache.
355 Under certain conditions this erratum can cause a clean line eviction
356 to occur at the same time as another transaction to the same address
357 on the AMBA 5 CHI interface, which can cause data corruption if the
358 interconnect reorders the two transactions.
360 The workaround promotes data cache clean instructions to
361 data cache clean-and-invalidate.
362 Please note that this does not necessarily enable the workaround,
363 as it depends on the alternative framework, which will only patch
364 the kernel if an affected CPU is detected.
368 config ARM64_ERRATUM_824069
369 bool "Cortex-A53: 824069: Cache line might not be marked as clean after a CleanShared snoop"
371 select ARM64_WORKAROUND_CLEAN_CACHE
373 This option adds an alternative code sequence to work around ARM
374 erratum 824069 on Cortex-A53 parts up to r0p2 when it is connected
375 to a coherent interconnect.
377 If a Cortex-A53 processor is executing a store or prefetch for
378 write instruction at the same time as a processor in another
379 cluster is executing a cache maintenance operation to the same
380 address, then this erratum might cause a clean cache line to be
381 incorrectly marked as dirty.
383 The workaround promotes data cache clean instructions to
384 data cache clean-and-invalidate.
385 Please note that this option does not necessarily enable the
386 workaround, as it depends on the alternative framework, which will
387 only patch the kernel if an affected CPU is detected.
391 config ARM64_ERRATUM_819472
392 bool "Cortex-A53: 819472: Store exclusive instructions might cause data corruption"
394 select ARM64_WORKAROUND_CLEAN_CACHE
396 This option adds an alternative code sequence to work around ARM
397 erratum 819472 on Cortex-A53 parts up to r0p1 with an L2 cache
398 present when it is connected to a coherent interconnect.
400 If the processor is executing a load and store exclusive sequence at
401 the same time as a processor in another cluster is executing a cache
402 maintenance operation to the same address, then this erratum might
403 cause data corruption.
405 The workaround promotes data cache clean instructions to
406 data cache clean-and-invalidate.
407 Please note that this does not necessarily enable the workaround,
408 as it depends on the alternative framework, which will only patch
409 the kernel if an affected CPU is detected.
413 config ARM64_ERRATUM_832075
414 bool "Cortex-A57: 832075: possible deadlock on mixing exclusive memory accesses with device loads"
417 This option adds an alternative code sequence to work around ARM
418 erratum 832075 on Cortex-A57 parts up to r1p2.
420 Affected Cortex-A57 parts might deadlock when exclusive load/store
421 instructions to Write-Back memory are mixed with Device loads.
423 The workaround is to promote device loads to use Load-Acquire
425 Please note that this does not necessarily enable the workaround,
426 as it depends on the alternative framework, which will only patch
427 the kernel if an affected CPU is detected.
431 config ARM64_ERRATUM_834220
432 bool "Cortex-A57: 834220: Stage 2 translation fault might be incorrectly reported in presence of a Stage 1 fault"
436 This option adds an alternative code sequence to work around ARM
437 erratum 834220 on Cortex-A57 parts up to r1p2.
439 Affected Cortex-A57 parts might report a Stage 2 translation
440 fault as the result of a Stage 1 fault for load crossing a
441 page boundary when there is a permission or device memory
442 alignment fault at Stage 1 and a translation fault at Stage 2.
444 The workaround is to verify that the Stage 1 translation
445 doesn't generate a fault before handling the Stage 2 fault.
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_845719
453 bool "Cortex-A53: 845719: a load might read incorrect data"
457 This option adds an alternative code sequence to work around ARM
458 erratum 845719 on Cortex-A53 parts up to r0p4.
460 When running a compat (AArch32) userspace on an affected Cortex-A53
461 part, a load at EL0 from a virtual address that matches the bottom 32
462 bits of the virtual address used by a recent load at (AArch64) EL1
463 might return incorrect data.
465 The workaround is to write the contextidr_el1 register on exception
466 return to a 32-bit task.
467 Please note that this does not necessarily enable the workaround,
468 as it depends on the alternative framework, which will only patch
469 the kernel if an affected CPU is detected.
473 config ARM64_ERRATUM_843419
474 bool "Cortex-A53: 843419: A load or store might access an incorrect address"
476 select ARM64_MODULE_PLTS if MODULES
478 This option links the kernel with '--fix-cortex-a53-843419' and
479 enables PLT support to replace certain ADRP instructions, which can
480 cause subsequent memory accesses to use an incorrect address on
481 Cortex-A53 parts up to r0p4.
485 config ARM64_ERRATUM_1024718
486 bool "Cortex-A55: 1024718: Update of DBM/AP bits without break before make might result in incorrect update"
489 This option adds a workaround for ARM Cortex-A55 Erratum 1024718.
491 Affected Cortex-A55 cores (all revisions) could cause incorrect
492 update of the hardware dirty bit when the DBM/AP bits are updated
493 without a break-before-make. The workaround is to disable the usage
494 of hardware DBM locally on the affected cores. CPUs not affected by
495 this erratum will continue to use the feature.
499 config ARM64_ERRATUM_1418040
500 bool "Cortex-A76/Neoverse-N1: MRC read following MRRC read of specific Generic Timer in AArch32 might give incorrect result"
504 This option adds a workaround for ARM Cortex-A76/Neoverse-N1
505 errata 1188873 and 1418040.
507 Affected Cortex-A76/Neoverse-N1 cores (r0p0 to r3p1) could
508 cause register corruption when accessing the timer registers
509 from AArch32 userspace.
513 config ARM64_ERRATUM_1165522
514 bool "Cortex-A76: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
517 This option adds a workaround for ARM Cortex-A76 erratum 1165522.
519 Affected Cortex-A76 cores (r0p0, r1p0, r2p0) could end-up with
520 corrupted TLBs by speculating an AT instruction during a guest
525 config ARM64_ERRATUM_1286807
526 bool "Cortex-A76: Modification of the translation table for a virtual address might lead to read-after-read ordering violation"
528 select ARM64_WORKAROUND_REPEAT_TLBI
530 This option adds a workaround for ARM Cortex-A76 erratum 1286807.
532 On the affected Cortex-A76 cores (r0p0 to r3p0), if a virtual
533 address for a cacheable mapping of a location is being
534 accessed by a core while another core is remapping the virtual
535 address to a new physical page using the recommended
536 break-before-make sequence, then under very rare circumstances
537 TLBI+DSB completes before a read using the translation being
538 invalidated has been observed by other observers. The
539 workaround repeats the TLBI+DSB operation.
543 config ARM64_ERRATUM_1463225
544 bool "Cortex-A76: Software Step might prevent interrupt recognition"
547 This option adds a workaround for Arm Cortex-A76 erratum 1463225.
549 On the affected Cortex-A76 cores (r0p0 to r3p1), software stepping
550 of a system call instruction (SVC) can prevent recognition of
551 subsequent interrupts when software stepping is disabled in the
552 exception handler of the system call and either kernel debugging
553 is enabled or VHE is in use.
555 Work around the erratum by triggering a dummy step exception
556 when handling a system call from a task that is being stepped
557 in a VHE configuration of the kernel.
561 config ARM64_ERRATUM_1542419
562 bool "Neoverse-N1: workaround mis-ordering of instruction fetches"
565 This option adds a workaround for ARM Neoverse-N1 erratum
568 Affected Neoverse-N1 cores could execute a stale instruction when
569 modified by another CPU. The workaround depends on a firmware
572 Workaround the issue by hiding the DIC feature from EL0. This
573 forces user-space to perform cache maintenance.
577 config ARM64_ERRATUM_1742098
578 bool "Cortex-A57/A72: 1742098: ELR recorded incorrectly on interrupt taken between cryptographic instructions in a sequence"
582 This option removes the AES hwcap for aarch32 user-space to
583 workaround erratum 1742098 on Cortex-A57 and Cortex-A72.
585 Affected parts may corrupt the AES state if an interrupt is
586 taken between a pair of AES instructions. These instructions
587 are only present if the cryptography extensions are present.
588 All software should have a fallback implementation for CPUs
589 that don't implement the cryptography extensions.
593 config CAVIUM_ERRATUM_22375
594 bool "Cavium erratum 22375, 24313"
597 Enable workaround for errata 22375 and 24313.
599 This implements two gicv3-its errata workarounds for ThunderX. Both
600 with a small impact affecting only ITS table allocation.
602 erratum 22375: only alloc 8MB table size
603 erratum 24313: ignore memory access type
605 The fixes are in ITS initialization and basically ignore memory access
606 type and table size provided by the TYPER and BASER registers.
610 config CAVIUM_ERRATUM_23144
611 bool "Cavium erratum 23144: ITS SYNC hang on dual socket system"
615 ITS SYNC command hang for cross node io and collections/cpu mapping.
619 config CAVIUM_ERRATUM_23154
620 bool "Cavium erratum 23154: Access to ICC_IAR1_EL1 is not sync'ed"
623 The gicv3 of ThunderX requires a modified version for
624 reading the IAR status to ensure data synchronization
625 (access to icc_iar1_el1 is not sync'ed before and after).
629 config CAVIUM_ERRATUM_27456
630 bool "Cavium erratum 27456: Broadcast TLBI instructions may cause icache corruption"
633 On ThunderX T88 pass 1.x through 2.1 parts, broadcast TLBI
634 instructions may cause the icache to become corrupted if it
635 contains data for a non-current ASID. The fix is to
636 invalidate the icache when changing the mm context.
640 config CAVIUM_ERRATUM_30115
641 bool "Cavium erratum 30115: Guest may disable interrupts in host"
644 On ThunderX T88 pass 1.x through 2.2, T81 pass 1.0 through
645 1.2, and T83 Pass 1.0, KVM guest execution may disable
646 interrupts in host. Trapping both GICv3 group-0 and group-1
647 accesses sidesteps the issue.
651 config CAVIUM_TX2_ERRATUM_219
652 bool "Cavium ThunderX2 erratum 219: PRFM between TTBR change and ISB fails"
655 On Cavium ThunderX2, a load, store or prefetch instruction between a
656 TTBR update and the corresponding context synchronizing operation can
657 cause a spurious Data Abort to be delivered to any hardware thread in
660 Work around the issue by avoiding the problematic code sequence and
661 trapping KVM guest TTBRx_EL1 writes to EL2 when SMT is enabled. The
662 trap handler performs the corresponding register access, skips the
663 instruction and ensures context synchronization by virtue of the
668 config QCOM_FALKOR_ERRATUM_1003
669 bool "Falkor E1003: Incorrect translation due to ASID change"
672 On Falkor v1, an incorrect ASID may be cached in the TLB when ASID
673 and BADDR are changed together in TTBRx_EL1. Since we keep the ASID
674 in TTBR1_EL1, this situation only occurs in the entry trampoline and
675 then only for entries in the walk cache, since the leaf translation
676 is unchanged. Work around the erratum by invalidating the walk cache
677 entries for the trampoline before entering the kernel proper.
679 config ARM64_WORKAROUND_REPEAT_TLBI
682 config QCOM_FALKOR_ERRATUM_1009
683 bool "Falkor E1009: Prematurely complete a DSB after a TLBI"
685 select ARM64_WORKAROUND_REPEAT_TLBI
687 On Falkor v1, the CPU may prematurely complete a DSB following a
688 TLBI xxIS invalidate maintenance operation. Repeat the TLBI operation
689 one more time to fix the issue.
693 config QCOM_QDF2400_ERRATUM_0065
694 bool "QDF2400 E0065: Incorrect GITS_TYPER.ITT_Entry_size"
697 On Qualcomm Datacenter Technologies QDF2400 SoC, ITS hardware reports
698 ITE size incorrectly. The GITS_TYPER.ITT_Entry_size field should have
699 been indicated as 16Bytes (0xf), not 8Bytes (0x7).
703 config SOCIONEXT_SYNQUACER_PREITS
704 bool "Socionext Synquacer: Workaround for GICv3 pre-ITS"
707 Socionext Synquacer SoCs implement a separate h/w block to generate
708 MSI doorbell writes with non-zero values for the device ID.
712 config HISILICON_ERRATUM_161600802
713 bool "Hip07 161600802: Erroneous redistributor VLPI base"
716 The HiSilicon Hip07 SoC uses the wrong redistributor base
717 when issued ITS commands such as VMOVP and VMAPP, and requires
718 a 128kB offset to be applied to the target address in this commands.
722 config QCOM_FALKOR_ERRATUM_E1041
723 bool "Falkor E1041: Speculative instruction fetches might cause errant memory access"
726 Falkor CPU may speculatively fetch instructions from an improper
727 memory location when MMU translation is changed from SCTLR_ELn[M]=1
728 to SCTLR_ELn[M]=0. Prefix an ISB instruction to fix the problem.
732 config FUJITSU_ERRATUM_010001
733 bool "Fujitsu-A64FX erratum E#010001: Undefined fault may occur wrongly"
736 This option adds a workaround for Fujitsu-A64FX erratum E#010001.
737 On some variants of the Fujitsu-A64FX cores ver(1.0, 1.1), memory
738 accesses may cause undefined fault (Data abort, DFSC=0b111111).
739 This fault occurs under a specific hardware condition when a
740 load/store instruction performs an address translation using:
741 case-1 TTBR0_EL1 with TCR_EL1.NFD0 == 1.
742 case-2 TTBR0_EL2 with TCR_EL2.NFD0 == 1.
743 case-3 TTBR1_EL1 with TCR_EL1.NFD1 == 1.
744 case-4 TTBR1_EL2 with TCR_EL2.NFD1 == 1.
746 The workaround is to ensure these bits are clear in TCR_ELx.
747 The workaround only affects the Fujitsu-A64FX.
756 default ARM64_4K_PAGES
758 Page size (translation granule) configuration.
760 config ARM64_4K_PAGES
763 This feature enables 4KB pages support.
765 config ARM64_16K_PAGES
768 The system will use 16KB pages support. AArch32 emulation
769 requires applications compiled with 16K (or a multiple of 16K)
772 config ARM64_64K_PAGES
775 This feature enables 64KB pages support (4KB by default)
776 allowing only two levels of page tables and faster TLB
777 look-up. AArch32 emulation requires applications compiled
778 with 64K aligned segments.
783 prompt "Virtual address space size"
784 default ARM64_VA_BITS_39 if ARM64_4K_PAGES
785 default ARM64_VA_BITS_47 if ARM64_16K_PAGES
786 default ARM64_VA_BITS_42 if ARM64_64K_PAGES
788 Allows choosing one of multiple possible virtual address
789 space sizes. The level of translation table is determined by
790 a combination of page size and virtual address space size.
792 config ARM64_VA_BITS_36
793 bool "36-bit" if EXPERT
794 depends on ARM64_16K_PAGES
796 config ARM64_VA_BITS_39
798 depends on ARM64_4K_PAGES
800 config ARM64_VA_BITS_42
802 depends on ARM64_64K_PAGES
804 config ARM64_VA_BITS_47
806 depends on ARM64_16K_PAGES
808 config ARM64_VA_BITS_48
811 config ARM64_VA_BITS_52
813 depends on ARM64_64K_PAGES && (ARM64_PAN || !ARM64_SW_TTBR0_PAN)
815 Enable 52-bit virtual addressing for userspace when explicitly
816 requested via a hint to mmap(). The kernel will also use 52-bit
817 virtual addresses for its own mappings (provided HW support for
818 this feature is available, otherwise it reverts to 48-bit).
820 NOTE: Enabling 52-bit virtual addressing in conjunction with
821 ARMv8.3 Pointer Authentication will result in the PAC being
822 reduced from 7 bits to 3 bits, which may have a significant
823 impact on its susceptibility to brute-force attacks.
825 If unsure, select 48-bit virtual addressing instead.
829 config ARM64_FORCE_52BIT
830 bool "Force 52-bit virtual addresses for userspace"
831 depends on ARM64_VA_BITS_52 && EXPERT
833 For systems with 52-bit userspace VAs enabled, the kernel will attempt
834 to maintain compatibility with older software by providing 48-bit VAs
835 unless a hint is supplied to mmap.
837 This configuration option disables the 48-bit compatibility logic, and
838 forces all userspace addresses to be 52-bit on HW that supports it. One
839 should only enable this configuration option for stress testing userspace
840 memory management code. If unsure say N here.
844 default 36 if ARM64_VA_BITS_36
845 default 39 if ARM64_VA_BITS_39
846 default 42 if ARM64_VA_BITS_42
847 default 47 if ARM64_VA_BITS_47
848 default 48 if ARM64_VA_BITS_48
849 default 52 if ARM64_VA_BITS_52
852 prompt "Physical address space size"
853 default ARM64_PA_BITS_48
855 Choose the maximum physical address range that the kernel will
858 config ARM64_PA_BITS_48
861 config ARM64_PA_BITS_52
862 bool "52-bit (ARMv8.2)"
863 depends on ARM64_64K_PAGES
864 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
866 Enable support for a 52-bit physical address space, introduced as
867 part of the ARMv8.2-LPA extension.
869 With this enabled, the kernel will also continue to work on CPUs that
870 do not support ARMv8.2-LPA, but with some added memory overhead (and
871 minor performance overhead).
877 default 48 if ARM64_PA_BITS_48
878 default 52 if ARM64_PA_BITS_52
880 config CPU_BIG_ENDIAN
881 bool "Build big-endian kernel"
883 Say Y if you plan on running a kernel in big-endian mode.
886 bool "Multi-core scheduler support"
888 Multi-core scheduler support improves the CPU scheduler's decision
889 making when dealing with multi-core CPU chips at a cost of slightly
890 increased overhead in some places. If unsure say N here.
893 bool "SMT scheduler support"
895 Improves the CPU scheduler's decision making when dealing with
896 MultiThreading at a cost of slightly increased overhead in some
897 places. If unsure say N here.
900 int "Maximum number of CPUs (2-4096)"
905 bool "Support for hot-pluggable CPUs"
906 select GENERIC_IRQ_MIGRATION
908 Say Y here to experiment with turning CPUs off and on. CPUs
909 can be controlled through /sys/devices/system/cpu.
911 # Common NUMA Features
913 bool "Numa Memory Allocation and Scheduler Support"
914 select ACPI_NUMA if ACPI
917 Enable NUMA (Non Uniform Memory Access) support.
919 The kernel will try to allocate memory used by a CPU on the
920 local memory of the CPU and add some more
921 NUMA awareness to the kernel.
924 int "Maximum NUMA Nodes (as a power of 2)"
927 depends on NEED_MULTIPLE_NODES
929 Specify the maximum number of NUMA Nodes available on the target
930 system. Increases memory reserved to accommodate various tables.
932 config USE_PERCPU_NUMA_NODE_ID
936 config HAVE_SETUP_PER_CPU_AREA
940 config NEED_PER_CPU_EMBED_FIRST_CHUNK
947 source "kernel/Kconfig.hz"
949 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
952 config ARCH_SPARSEMEM_ENABLE
954 select SPARSEMEM_VMEMMAP_ENABLE
956 config ARCH_SPARSEMEM_DEFAULT
957 def_bool ARCH_SPARSEMEM_ENABLE
959 config ARCH_SELECT_MEMORY_MODEL
960 def_bool ARCH_SPARSEMEM_ENABLE
962 config ARCH_FLATMEM_ENABLE
965 config HAVE_ARCH_PFN_VALID
968 config HW_PERF_EVENTS
972 config SYS_SUPPORTS_HUGETLBFS
975 config ARCH_WANT_HUGE_PMD_SHARE
977 config ARCH_HAS_CACHE_LINE_SIZE
980 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
981 def_bool y if PGTABLE_LEVELS > 2
984 bool "Enable seccomp to safely compute untrusted bytecode"
986 This kernel feature is useful for number crunching applications
987 that may need to compute untrusted bytecode during their
988 execution. By using pipes or other transports made available to
989 the process as file descriptors supporting the read/write
990 syscalls, it's possible to isolate those applications in
991 their own address space using seccomp. Once seccomp is
992 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
993 and the task is only allowed to execute a few safe syscalls
994 defined by each seccomp mode.
997 bool "Enable paravirtualization code"
999 This changes the kernel so it can modify itself when it is run
1000 under a hypervisor, potentially improving performance significantly
1001 over full virtualization.
1003 config PARAVIRT_TIME_ACCOUNTING
1004 bool "Paravirtual steal time accounting"
1007 Select this option to enable fine granularity task steal time
1008 accounting. Time spent executing other tasks in parallel with
1009 the current vCPU is discounted from the vCPU power. To account for
1010 that, there can be a small performance impact.
1012 If in doubt, say N here.
1015 depends on PM_SLEEP_SMP
1017 bool "kexec system call"
1019 kexec is a system call that implements the ability to shutdown your
1020 current kernel, and to start another kernel. It is like a reboot
1021 but it is independent of the system firmware. And like a reboot
1022 you can start any kernel with it, not just Linux.
1025 bool "kexec file based system call"
1028 This is new version of kexec system call. This system call is
1029 file based and takes file descriptors as system call argument
1030 for kernel and initramfs as opposed to list of segments as
1031 accepted by previous system call.
1034 bool "Verify kernel signature during kexec_file_load() syscall"
1035 depends on KEXEC_FILE
1037 Select this option to verify a signature with loaded kernel
1038 image. If configured, any attempt of loading a image without
1039 valid signature will fail.
1041 In addition to that option, you need to enable signature
1042 verification for the corresponding kernel image type being
1043 loaded in order for this to work.
1045 config KEXEC_IMAGE_VERIFY_SIG
1046 bool "Enable Image signature verification support"
1048 depends on KEXEC_SIG
1049 depends on EFI && SIGNED_PE_FILE_VERIFICATION
1051 Enable Image signature verification support.
1053 comment "Support for PE file signature verification disabled"
1054 depends on KEXEC_SIG
1055 depends on !EFI || !SIGNED_PE_FILE_VERIFICATION
1058 bool "Build kdump crash kernel"
1060 Generate crash dump after being started by kexec. This should
1061 be normally only set in special crash dump kernels which are
1062 loaded in the main kernel with kexec-tools into a specially
1063 reserved region and then later executed after a crash by
1066 For more details see Documentation/admin-guide/kdump/kdump.rst
1073 bool "Xen guest support on ARM64"
1074 depends on ARM64 && OF
1078 Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64.
1080 config FORCE_MAX_ZONEORDER
1082 default "14" if (ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE)
1083 default "12" if (ARM64_16K_PAGES && TRANSPARENT_HUGEPAGE)
1086 The kernel memory allocator divides physically contiguous memory
1087 blocks into "zones", where each zone is a power of two number of
1088 pages. This option selects the largest power of two that the kernel
1089 keeps in the memory allocator. If you need to allocate very large
1090 blocks of physically contiguous memory, then you may need to
1091 increase this value.
1093 This config option is actually maximum order plus one. For example,
1094 a value of 11 means that the largest free memory block is 2^10 pages.
1096 We make sure that we can allocate upto a HugePage size for each configuration.
1098 MAX_ORDER = (PMD_SHIFT - PAGE_SHIFT) + 1 => PAGE_SHIFT - 2
1100 However for 4K, we choose a higher default value, 11 as opposed to 10, giving us
1101 4M allocations matching the default size used by generic code.
1103 config UNMAP_KERNEL_AT_EL0
1104 bool "Unmap kernel when running in userspace (aka \"KAISER\")" if EXPERT
1107 Speculation attacks against some high-performance processors can
1108 be used to bypass MMU permission checks and leak kernel data to
1109 userspace. This can be defended against by unmapping the kernel
1110 when running in userspace, mapping it back in on exception entry
1111 via a trampoline page in the vector table.
1115 config HARDEN_BRANCH_PREDICTOR
1116 bool "Harden the branch predictor against aliasing attacks" if EXPERT
1119 Speculation attacks against some high-performance processors rely on
1120 being able to manipulate the branch predictor for a victim context by
1121 executing aliasing branches in the attacker context. Such attacks
1122 can be partially mitigated against by clearing internal branch
1123 predictor state and limiting the prediction logic in some situations.
1125 This config option will take CPU-specific actions to harden the
1126 branch predictor against aliasing attacks and may rely on specific
1127 instruction sequences or control bits being set by the system
1132 config HARDEN_EL2_VECTORS
1133 bool "Harden EL2 vector mapping against system register leak" if EXPERT
1136 Speculation attacks against some high-performance processors can
1137 be used to leak privileged information such as the vector base
1138 register, resulting in a potential defeat of the EL2 layout
1141 This config option will map the vectors to a fixed location,
1142 independent of the EL2 code mapping, so that revealing VBAR_EL2
1143 to an attacker does not give away any extra information. This
1144 only gets enabled on affected CPUs.
1149 bool "Speculative Store Bypass Disable" if EXPERT
1152 This enables mitigation of the bypassing of previous stores
1153 by speculative loads.
1157 config MITIGATE_SPECTRE_BRANCH_HISTORY
1158 bool "Mitigate Spectre style attacks against branch history" if EXPERT
1161 Speculation attacks against some high-performance processors can
1162 make use of branch history to influence future speculation.
1163 When taking an exception from user-space, a sequence of branches
1164 or a firmware call overwrites the branch history.
1166 config RODATA_FULL_DEFAULT_ENABLED
1167 bool "Apply r/o permissions of VM areas also to their linear aliases"
1170 Apply read-only attributes of VM areas to the linear alias of
1171 the backing pages as well. This prevents code or read-only data
1172 from being modified (inadvertently or intentionally) via another
1173 mapping of the same memory page. This additional enhancement can
1174 be turned off at runtime by passing rodata=[off|on] (and turned on
1175 with rodata=full if this option is set to 'n')
1177 This requires the linear region to be mapped down to pages,
1178 which may adversely affect performance in some cases.
1180 config ARM64_SW_TTBR0_PAN
1181 bool "Emulate Privileged Access Never using TTBR0_EL1 switching"
1183 Enabling this option prevents the kernel from accessing
1184 user-space memory directly by pointing TTBR0_EL1 to a reserved
1185 zeroed area and reserved ASID. The user access routines
1186 restore the valid TTBR0_EL1 temporarily.
1188 config ARM64_TAGGED_ADDR_ABI
1189 bool "Enable the tagged user addresses syscall ABI"
1192 When this option is enabled, user applications can opt in to a
1193 relaxed ABI via prctl() allowing tagged addresses to be passed
1194 to system calls as pointer arguments. For details, see
1195 Documentation/arm64/tagged-address-abi.rst.
1198 bool "Kernel support for 32-bit EL0"
1199 depends on ARM64_4K_PAGES || EXPERT
1200 select COMPAT_BINFMT_ELF if BINFMT_ELF
1202 select OLD_SIGSUSPEND3
1203 select COMPAT_OLD_SIGACTION
1205 This option enables support for a 32-bit EL0 running under a 64-bit
1206 kernel at EL1. AArch32-specific components such as system calls,
1207 the user helper functions, VFP support and the ptrace interface are
1208 handled appropriately by the kernel.
1210 If you use a page size other than 4KB (i.e, 16KB or 64KB), please be aware
1211 that you will only be able to execute AArch32 binaries that were compiled
1212 with page size aligned segments.
1214 If you want to execute 32-bit userspace applications, say Y.
1218 config KUSER_HELPERS
1219 bool "Enable kuser helpers page for 32-bit applications"
1222 Warning: disabling this option may break 32-bit user programs.
1224 Provide kuser helpers to compat tasks. The kernel provides
1225 helper code to userspace in read only form at a fixed location
1226 to allow userspace to be independent of the CPU type fitted to
1227 the system. This permits binaries to be run on ARMv4 through
1228 to ARMv8 without modification.
1230 See Documentation/arm/kernel_user_helpers.rst for details.
1232 However, the fixed address nature of these helpers can be used
1233 by ROP (return orientated programming) authors when creating
1236 If all of the binaries and libraries which run on your platform
1237 are built specifically for your platform, and make no use of
1238 these helpers, then you can turn this option off to hinder
1239 such exploits. However, in that case, if a binary or library
1240 relying on those helpers is run, it will not function correctly.
1242 Say N here only if you are absolutely certain that you do not
1243 need these helpers; otherwise, the safe option is to say Y.
1246 bool "Enable vDSO for 32-bit applications"
1247 depends on !CPU_BIG_ENDIAN && "$(CROSS_COMPILE_COMPAT)" != ""
1248 select GENERIC_COMPAT_VDSO
1251 Place in the process address space of 32-bit applications an
1252 ELF shared object providing fast implementations of gettimeofday
1255 You must have a 32-bit build of glibc 2.22 or later for programs
1256 to seamlessly take advantage of this.
1258 menuconfig ARMV8_DEPRECATED
1259 bool "Emulate deprecated/obsolete ARMv8 instructions"
1262 Legacy software support may require certain instructions
1263 that have been deprecated or obsoleted in the architecture.
1265 Enable this config to enable selective emulation of these
1272 config SWP_EMULATION
1273 bool "Emulate SWP/SWPB instructions"
1275 ARMv8 obsoletes the use of A32 SWP/SWPB instructions such that
1276 they are always undefined. Say Y here to enable software
1277 emulation of these instructions for userspace using LDXR/STXR.
1279 In some older versions of glibc [<=2.8] SWP is used during futex
1280 trylock() operations with the assumption that the code will not
1281 be preempted. This invalid assumption may be more likely to fail
1282 with SWP emulation enabled, leading to deadlock of the user
1285 NOTE: when accessing uncached shared regions, LDXR/STXR rely
1286 on an external transaction monitoring block called a global
1287 monitor to maintain update atomicity. If your system does not
1288 implement a global monitor, this option can cause programs that
1289 perform SWP operations to uncached memory to deadlock.
1293 config CP15_BARRIER_EMULATION
1294 bool "Emulate CP15 Barrier instructions"
1296 The CP15 barrier instructions - CP15ISB, CP15DSB, and
1297 CP15DMB - are deprecated in ARMv8 (and ARMv7). It is
1298 strongly recommended to use the ISB, DSB, and DMB
1299 instructions instead.
1301 Say Y here to enable software emulation of these
1302 instructions for AArch32 userspace code. When this option is
1303 enabled, CP15 barrier usage is traced which can help
1304 identify software that needs updating.
1308 config SETEND_EMULATION
1309 bool "Emulate SETEND instruction"
1311 The SETEND instruction alters the data-endianness of the
1312 AArch32 EL0, and is deprecated in ARMv8.
1314 Say Y here to enable software emulation of the instruction
1315 for AArch32 userspace code.
1317 Note: All the cpus on the system must have mixed endian support at EL0
1318 for this feature to be enabled. If a new CPU - which doesn't support mixed
1319 endian - is hotplugged in after this feature has been enabled, there could
1320 be unexpected results in the applications.
1327 menu "ARMv8.1 architectural features"
1329 config ARM64_HW_AFDBM
1330 bool "Support for hardware updates of the Access and Dirty page flags"
1333 The ARMv8.1 architecture extensions introduce support for
1334 hardware updates of the access and dirty information in page
1335 table entries. When enabled in TCR_EL1 (HA and HD bits) on
1336 capable processors, accesses to pages with PTE_AF cleared will
1337 set this bit instead of raising an access flag fault.
1338 Similarly, writes to read-only pages with the DBM bit set will
1339 clear the read-only bit (AP[2]) instead of raising a
1342 Kernels built with this configuration option enabled continue
1343 to work on pre-ARMv8.1 hardware and the performance impact is
1344 minimal. If unsure, say Y.
1347 bool "Enable support for Privileged Access Never (PAN)"
1350 Privileged Access Never (PAN; part of the ARMv8.1 Extensions)
1351 prevents the kernel or hypervisor from accessing user-space (EL0)
1354 Choosing this option will cause any unprotected (not using
1355 copy_to_user et al) memory access to fail with a permission fault.
1357 The feature is detected at runtime, and will remain as a 'nop'
1358 instruction if the cpu does not implement the feature.
1360 config ARM64_LSE_ATOMICS
1361 bool "Atomic instructions"
1362 depends on JUMP_LABEL
1365 As part of the Large System Extensions, ARMv8.1 introduces new
1366 atomic instructions that are designed specifically to scale in
1369 Say Y here to make use of these instructions for the in-kernel
1370 atomic routines. This incurs a small overhead on CPUs that do
1371 not support these instructions and requires the kernel to be
1372 built with binutils >= 2.25 in order for the new instructions
1376 bool "Enable support for Virtualization Host Extensions (VHE)"
1379 Virtualization Host Extensions (VHE) allow the kernel to run
1380 directly at EL2 (instead of EL1) on processors that support
1381 it. This leads to better performance for KVM, as they reduce
1382 the cost of the world switch.
1384 Selecting this option allows the VHE feature to be detected
1385 at runtime, and does not affect processors that do not
1386 implement this feature.
1390 menu "ARMv8.2 architectural features"
1393 bool "Enable support for User Access Override (UAO)"
1396 User Access Override (UAO; part of the ARMv8.2 Extensions)
1397 causes the 'unprivileged' variant of the load/store instructions to
1398 be overridden to be privileged.
1400 This option changes get_user() and friends to use the 'unprivileged'
1401 variant of the load/store instructions. This ensures that user-space
1402 really did have access to the supplied memory. When addr_limit is
1403 set to kernel memory the UAO bit will be set, allowing privileged
1404 access to kernel memory.
1406 Choosing this option will cause copy_to_user() et al to use user-space
1409 The feature is detected at runtime, the kernel will use the
1410 regular load/store instructions if the cpu does not implement the
1414 bool "Enable support for persistent memory"
1415 select ARCH_HAS_PMEM_API
1416 select ARCH_HAS_UACCESS_FLUSHCACHE
1418 Say Y to enable support for the persistent memory API based on the
1419 ARMv8.2 DCPoP feature.
1421 The feature is detected at runtime, and the kernel will use DC CVAC
1422 operations if DC CVAP is not supported (following the behaviour of
1423 DC CVAP itself if the system does not define a point of persistence).
1425 config ARM64_RAS_EXTN
1426 bool "Enable support for RAS CPU Extensions"
1429 CPUs that support the Reliability, Availability and Serviceability
1430 (RAS) Extensions, part of ARMv8.2 are able to track faults and
1431 errors, classify them and report them to software.
1433 On CPUs with these extensions system software can use additional
1434 barriers to determine if faults are pending and read the
1435 classification from a new set of registers.
1437 Selecting this feature will allow the kernel to use these barriers
1438 and access the new registers if the system supports the extension.
1439 Platform RAS features may additionally depend on firmware support.
1442 bool "Enable support for Common Not Private (CNP) translations"
1444 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
1446 Common Not Private (CNP) allows translation table entries to
1447 be shared between different PEs in the same inner shareable
1448 domain, so the hardware can use this fact to optimise the
1449 caching of such entries in the TLB.
1451 Selecting this option allows the CNP feature to be detected
1452 at runtime, and does not affect PEs that do not implement
1457 menu "ARMv8.3 architectural features"
1459 config ARM64_PTR_AUTH
1460 bool "Enable support for pointer authentication"
1462 depends on !KVM || ARM64_VHE
1464 Pointer authentication (part of the ARMv8.3 Extensions) provides
1465 instructions for signing and authenticating pointers against secret
1466 keys, which can be used to mitigate Return Oriented Programming (ROP)
1469 This option enables these instructions at EL0 (i.e. for userspace).
1471 Choosing this option will cause the kernel to initialise secret keys
1472 for each process at exec() time, with these keys being
1473 context-switched along with the process.
1475 The feature is detected at runtime. If the feature is not present in
1476 hardware it will not be advertised to userspace/KVM guest nor will it
1477 be enabled. However, KVM guest also require VHE mode and hence
1478 CONFIG_ARM64_VHE=y option to use this feature.
1483 bool "ARM Scalable Vector Extension support"
1485 depends on !KVM || ARM64_VHE
1487 The Scalable Vector Extension (SVE) is an extension to the AArch64
1488 execution state which complements and extends the SIMD functionality
1489 of the base architecture to support much larger vectors and to enable
1490 additional vectorisation opportunities.
1492 To enable use of this extension on CPUs that implement it, say Y.
1494 On CPUs that support the SVE2 extensions, this option will enable
1497 Note that for architectural reasons, firmware _must_ implement SVE
1498 support when running on SVE capable hardware. The required support
1501 * version 1.5 and later of the ARM Trusted Firmware
1502 * the AArch64 boot wrapper since commit 5e1261e08abf
1503 ("bootwrapper: SVE: Enable SVE for EL2 and below").
1505 For other firmware implementations, consult the firmware documentation
1508 If you need the kernel to boot on SVE-capable hardware with broken
1509 firmware, you may need to say N here until you get your firmware
1510 fixed. Otherwise, you may experience firmware panics or lockups when
1511 booting the kernel. If unsure and you are not observing these
1512 symptoms, you should assume that it is safe to say Y.
1514 CPUs that support SVE are architecturally required to support the
1515 Virtualization Host Extensions (VHE), so the kernel makes no
1516 provision for supporting SVE alongside KVM without VHE enabled.
1517 Thus, you will need to enable CONFIG_ARM64_VHE if you want to support
1518 KVM in the same kernel image.
1520 config ARM64_MODULE_PLTS
1521 bool "Use PLTs to allow module memory to spill over into vmalloc area"
1523 select HAVE_MOD_ARCH_SPECIFIC
1525 Allocate PLTs when loading modules so that jumps and calls whose
1526 targets are too far away for their relative offsets to be encoded
1527 in the instructions themselves can be bounced via veneers in the
1528 module's PLT. This allows modules to be allocated in the generic
1529 vmalloc area after the dedicated module memory area has been
1532 When running with address space randomization (KASLR), the module
1533 region itself may be too far away for ordinary relative jumps and
1534 calls, and so in that case, module PLTs are required and cannot be
1537 Specific errata workaround(s) might also force module PLTs to be
1538 enabled (ARM64_ERRATUM_843419).
1540 config ARM64_PSEUDO_NMI
1541 bool "Support for NMI-like interrupts"
1542 select CONFIG_ARM_GIC_V3
1544 Adds support for mimicking Non-Maskable Interrupts through the use of
1545 GIC interrupt priority. This support requires version 3 or later of
1548 This high priority configuration for interrupts needs to be
1549 explicitly enabled by setting the kernel parameter
1550 "irqchip.gicv3_pseudo_nmi" to 1.
1555 config ARM64_DEBUG_PRIORITY_MASKING
1556 bool "Debug interrupt priority masking"
1558 This adds runtime checks to functions enabling/disabling
1559 interrupts when using priority masking. The additional checks verify
1560 the validity of ICC_PMR_EL1 when calling concerned functions.
1567 select ARCH_HAS_RELR
1569 This builds the kernel as a Position Independent Executable (PIE),
1570 which retains all relocation metadata required to relocate the
1571 kernel binary at runtime to a different virtual address than the
1572 address it was linked at.
1573 Since AArch64 uses the RELA relocation format, this requires a
1574 relocation pass at runtime even if the kernel is loaded at the
1575 same address it was linked at.
1577 config RANDOMIZE_BASE
1578 bool "Randomize the address of the kernel image"
1579 select ARM64_MODULE_PLTS if MODULES
1582 Randomizes the virtual address at which the kernel image is
1583 loaded, as a security feature that deters exploit attempts
1584 relying on knowledge of the location of kernel internals.
1586 It is the bootloader's job to provide entropy, by passing a
1587 random u64 value in /chosen/kaslr-seed at kernel entry.
1589 When booting via the UEFI stub, it will invoke the firmware's
1590 EFI_RNG_PROTOCOL implementation (if available) to supply entropy
1591 to the kernel proper. In addition, it will randomise the physical
1592 location of the kernel Image as well.
1596 config RANDOMIZE_MODULE_REGION_FULL
1597 bool "Randomize the module region over a 4 GB range"
1598 depends on RANDOMIZE_BASE
1601 Randomizes the location of the module region inside a 4 GB window
1602 covering the core kernel. This way, it is less likely for modules
1603 to leak information about the location of core kernel data structures
1604 but it does imply that function calls between modules and the core
1605 kernel will need to be resolved via veneers in the module PLT.
1607 When this option is not set, the module region will be randomized over
1608 a limited range that contains the [_stext, _etext] interval of the
1609 core kernel, so branch relocations are always in range.
1611 config CC_HAVE_STACKPROTECTOR_SYSREG
1612 def_bool $(cc-option,-mstack-protector-guard=sysreg -mstack-protector-guard-reg=sp_el0 -mstack-protector-guard-offset=0)
1614 config STACKPROTECTOR_PER_TASK
1616 depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_SYSREG
1622 config ARM64_ACPI_PARKING_PROTOCOL
1623 bool "Enable support for the ARM64 ACPI parking protocol"
1626 Enable support for the ARM64 ACPI parking protocol. If disabled
1627 the kernel will not allow booting through the ARM64 ACPI parking
1628 protocol even if the corresponding data is present in the ACPI
1632 string "Default kernel command string"
1635 Provide a set of default command-line options at build time by
1636 entering them here. As a minimum, you should specify the the
1637 root device (e.g. root=/dev/nfs).
1639 config CMDLINE_FORCE
1640 bool "Always use the default kernel command string"
1642 Always use the default kernel command string, even if the boot
1643 loader passes other arguments to the kernel.
1644 This is useful if you cannot or don't want to change the
1645 command-line options your boot loader passes to the kernel.
1651 bool "UEFI runtime support"
1652 depends on OF && !CPU_BIG_ENDIAN
1653 depends on KERNEL_MODE_NEON
1654 select ARCH_SUPPORTS_ACPI
1657 select EFI_PARAMS_FROM_FDT
1658 select EFI_RUNTIME_WRAPPERS
1663 This option provides support for runtime services provided
1664 by UEFI firmware (such as non-volatile variables, realtime
1665 clock, and platform reset). A UEFI stub is also provided to
1666 allow the kernel to be booted as an EFI application. This
1667 is only useful on systems that have UEFI firmware.
1670 bool "Enable support for SMBIOS (DMI) tables"
1674 This enables SMBIOS/DMI feature for systems.
1676 This option is only useful on systems that have UEFI firmware.
1677 However, even with this option, the resultant kernel should
1678 continue to boot on existing non-UEFI platforms.
1682 config SYSVIPC_COMPAT
1684 depends on COMPAT && SYSVIPC
1686 config ARCH_ENABLE_HUGEPAGE_MIGRATION
1688 depends on HUGETLB_PAGE && MIGRATION
1690 menu "Power management options"
1692 source "kernel/power/Kconfig"
1694 config ARCH_HIBERNATION_POSSIBLE
1698 config ARCH_HIBERNATION_HEADER
1700 depends on HIBERNATION
1702 config ARCH_SUSPEND_POSSIBLE
1707 menu "CPU Power Management"
1709 source "drivers/cpuidle/Kconfig"
1711 source "drivers/cpufreq/Kconfig"
1715 source "drivers/firmware/Kconfig"
1717 source "drivers/acpi/Kconfig"
1719 source "arch/arm64/kvm/Kconfig"
1722 source "arch/arm64/crypto/Kconfig"