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_EXTRA_PHDRS
14 select ARCH_BINFMT_ELF_STATE
15 select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
16 select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION
17 select ARCH_ENABLE_MEMORY_HOTPLUG
18 select ARCH_ENABLE_MEMORY_HOTREMOVE
19 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
20 select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE
21 select ARCH_HAS_CACHE_LINE_SIZE
22 select ARCH_HAS_DEBUG_VIRTUAL
23 select ARCH_HAS_DEBUG_VM_PGTABLE
24 select ARCH_HAS_DMA_PREP_COHERENT
25 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
26 select ARCH_HAS_FAST_MULTIPLIER
27 select ARCH_HAS_FORTIFY_SOURCE
28 select ARCH_HAS_GCOV_PROFILE_ALL
29 select ARCH_HAS_GIGANTIC_PAGE
31 select ARCH_HAS_KEEPINITRD
32 select ARCH_HAS_MEMBARRIER_SYNC_CORE
33 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
34 select ARCH_HAS_PTE_DEVMAP
35 select ARCH_HAS_PTE_SPECIAL
36 select ARCH_HAS_SETUP_DMA_OPS
37 select ARCH_HAS_SET_DIRECT_MAP
38 select ARCH_HAS_SET_MEMORY
40 select ARCH_HAS_STRICT_KERNEL_RWX
41 select ARCH_HAS_STRICT_MODULE_RWX
42 select ARCH_HAS_SYNC_DMA_FOR_DEVICE
43 select ARCH_HAS_SYNC_DMA_FOR_CPU
44 select ARCH_HAS_SYSCALL_WRAPPER
45 select ARCH_HAS_TEARDOWN_DMA_OPS if IOMMU_SUPPORT
46 select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
47 select ARCH_HAS_ZONE_DMA_SET if EXPERT
48 select ARCH_HAVE_ELF_PROT
49 select ARCH_HAVE_NMI_SAFE_CMPXCHG
50 select ARCH_INLINE_READ_LOCK if !PREEMPTION
51 select ARCH_INLINE_READ_LOCK_BH if !PREEMPTION
52 select ARCH_INLINE_READ_LOCK_IRQ if !PREEMPTION
53 select ARCH_INLINE_READ_LOCK_IRQSAVE if !PREEMPTION
54 select ARCH_INLINE_READ_UNLOCK if !PREEMPTION
55 select ARCH_INLINE_READ_UNLOCK_BH if !PREEMPTION
56 select ARCH_INLINE_READ_UNLOCK_IRQ if !PREEMPTION
57 select ARCH_INLINE_READ_UNLOCK_IRQRESTORE if !PREEMPTION
58 select ARCH_INLINE_WRITE_LOCK if !PREEMPTION
59 select ARCH_INLINE_WRITE_LOCK_BH if !PREEMPTION
60 select ARCH_INLINE_WRITE_LOCK_IRQ if !PREEMPTION
61 select ARCH_INLINE_WRITE_LOCK_IRQSAVE if !PREEMPTION
62 select ARCH_INLINE_WRITE_UNLOCK if !PREEMPTION
63 select ARCH_INLINE_WRITE_UNLOCK_BH if !PREEMPTION
64 select ARCH_INLINE_WRITE_UNLOCK_IRQ if !PREEMPTION
65 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE if !PREEMPTION
66 select ARCH_INLINE_SPIN_TRYLOCK if !PREEMPTION
67 select ARCH_INLINE_SPIN_TRYLOCK_BH if !PREEMPTION
68 select ARCH_INLINE_SPIN_LOCK if !PREEMPTION
69 select ARCH_INLINE_SPIN_LOCK_BH if !PREEMPTION
70 select ARCH_INLINE_SPIN_LOCK_IRQ if !PREEMPTION
71 select ARCH_INLINE_SPIN_LOCK_IRQSAVE if !PREEMPTION
72 select ARCH_INLINE_SPIN_UNLOCK if !PREEMPTION
73 select ARCH_INLINE_SPIN_UNLOCK_BH if !PREEMPTION
74 select ARCH_INLINE_SPIN_UNLOCK_IRQ if !PREEMPTION
75 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPTION
76 select ARCH_KEEP_MEMBLOCK
77 select ARCH_USE_CMPXCHG_LOCKREF
78 select ARCH_USE_GNU_PROPERTY
79 select ARCH_USE_MEMTEST
80 select ARCH_USE_QUEUED_RWLOCKS
81 select ARCH_USE_QUEUED_SPINLOCKS
82 select ARCH_USE_SYM_ANNOTATIONS
83 select ARCH_SUPPORTS_DEBUG_PAGEALLOC
84 select ARCH_SUPPORTS_HUGETLBFS
85 select ARCH_SUPPORTS_MEMORY_FAILURE
86 select ARCH_SUPPORTS_SHADOW_CALL_STACK if CC_HAVE_SHADOW_CALL_STACK
87 select ARCH_SUPPORTS_LTO_CLANG if CPU_LITTLE_ENDIAN
88 select ARCH_SUPPORTS_LTO_CLANG_THIN
89 select ARCH_SUPPORTS_CFI_CLANG
90 select ARCH_SUPPORTS_ATOMIC_RMW
91 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
92 select ARCH_SUPPORTS_NUMA_BALANCING
93 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT
94 select ARCH_WANT_DEFAULT_BPF_JIT
95 select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
96 select ARCH_WANT_FRAME_POINTERS
97 select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
98 select ARCH_WANT_LD_ORPHAN_WARN
99 select ARCH_WANTS_NO_INSTR
100 select ARCH_HAS_UBSAN_SANITIZE_ALL
102 select ARM_ARCH_TIMER
104 select AUDIT_ARCH_COMPAT_GENERIC
105 select ARM_GIC_V2M if PCI
107 select ARM_GIC_V3_ITS if PCI
109 select BUILDTIME_TABLE_SORT
110 select CLONE_BACKWARDS
112 select CPU_PM if (SUSPEND || CPU_IDLE)
114 select DCACHE_WORD_ACCESS
115 select DMA_DIRECT_REMAP
118 select GENERIC_ALLOCATOR
119 select GENERIC_ARCH_TOPOLOGY
120 select GENERIC_CLOCKEVENTS_BROADCAST
121 select GENERIC_CPU_AUTOPROBE
122 select GENERIC_CPU_VULNERABILITIES
123 select GENERIC_EARLY_IOREMAP
124 select GENERIC_IDLE_POLL_SETUP
125 select GENERIC_IRQ_IPI
126 select GENERIC_IRQ_PROBE
127 select GENERIC_IRQ_SHOW
128 select GENERIC_IRQ_SHOW_LEVEL
129 select GENERIC_LIB_DEVMEM_IS_ALLOWED
130 select GENERIC_PCI_IOMAP
131 select GENERIC_PTDUMP
132 select GENERIC_SCHED_CLOCK
133 select GENERIC_SMP_IDLE_THREAD
134 select GENERIC_TIME_VSYSCALL
135 select GENERIC_GETTIMEOFDAY
136 select GENERIC_VDSO_TIME_NS
137 select HARDIRQS_SW_RESEND
141 select HAVE_ACPI_APEI if (ACPI && EFI)
142 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
143 select HAVE_ARCH_AUDITSYSCALL
144 select HAVE_ARCH_BITREVERSE
145 select HAVE_ARCH_COMPILER_H
146 select HAVE_ARCH_HUGE_VMAP
147 select HAVE_ARCH_JUMP_LABEL
148 select HAVE_ARCH_JUMP_LABEL_RELATIVE
149 select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48)
150 select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN
151 select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN
152 select HAVE_ARCH_KASAN_HW_TAGS if (HAVE_ARCH_KASAN && ARM64_MTE)
153 # Some instrumentation may be unsound, hence EXPERT
154 select HAVE_ARCH_KCSAN if EXPERT
155 select HAVE_ARCH_KFENCE
156 select HAVE_ARCH_KGDB
157 select HAVE_ARCH_MMAP_RND_BITS
158 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
159 select HAVE_ARCH_PREL32_RELOCATIONS
160 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
161 select HAVE_ARCH_SECCOMP_FILTER
162 select HAVE_ARCH_STACKLEAK
163 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
164 select HAVE_ARCH_TRACEHOOK
165 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
166 select HAVE_ARCH_VMAP_STACK
167 select HAVE_ARM_SMCCC
168 select HAVE_ASM_MODVERSIONS
170 select HAVE_C_RECORDMCOUNT
171 select HAVE_CMPXCHG_DOUBLE
172 select HAVE_CMPXCHG_LOCAL
173 select HAVE_CONTEXT_TRACKING
174 select HAVE_DEBUG_KMEMLEAK
175 select HAVE_DMA_CONTIGUOUS
176 select HAVE_DYNAMIC_FTRACE
177 select HAVE_DYNAMIC_FTRACE_WITH_REGS \
178 if $(cc-option,-fpatchable-function-entry=2)
179 select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY \
180 if DYNAMIC_FTRACE_WITH_REGS
181 select HAVE_EFFICIENT_UNALIGNED_ACCESS
183 select HAVE_FTRACE_MCOUNT_RECORD
184 select HAVE_FUNCTION_TRACER
185 select HAVE_FUNCTION_ERROR_INJECTION
186 select HAVE_FUNCTION_GRAPH_TRACER
187 select HAVE_GCC_PLUGINS
188 select HAVE_HW_BREAKPOINT if PERF_EVENTS
189 select HAVE_IRQ_TIME_ACCOUNTING
192 select HAVE_PATA_PLATFORM
193 select HAVE_PERF_EVENTS
194 select HAVE_PERF_REGS
195 select HAVE_PERF_USER_STACK_DUMP
196 select HAVE_REGS_AND_STACK_ACCESS_API
197 select HAVE_POSIX_CPU_TIMERS_TASK_WORK
198 select HAVE_FUNCTION_ARG_ACCESS_API
199 select MMU_GATHER_RCU_TABLE_FREE
201 select HAVE_STACKPROTECTOR
202 select HAVE_SYSCALL_TRACEPOINTS
204 select HAVE_KRETPROBES
205 select HAVE_GENERIC_VDSO
206 select IOMMU_DMA if IOMMU_SUPPORT
208 select IRQ_FORCED_THREADING
209 select KASAN_VMALLOC if KASAN_GENERIC
210 select MODULES_USE_ELF_RELA
211 select NEED_DMA_MAP_STATE
212 select NEED_SG_DMA_LENGTH
214 select OF_EARLY_FLATTREE
215 select PCI_DOMAINS_GENERIC if PCI
216 select PCI_ECAM if (ACPI && PCI)
217 select PCI_SYSCALL if PCI
222 select SYSCTL_EXCEPTION_TRACE
223 select THREAD_INFO_IN_TASK
224 select HAVE_ARCH_USERFAULTFD_MINOR if USERFAULTFD
225 select TRACE_IRQFLAGS_SUPPORT
227 ARM 64-bit (AArch64) Linux support.
235 config ARM64_PAGE_SHIFT
237 default 16 if ARM64_64K_PAGES
238 default 14 if ARM64_16K_PAGES
241 config ARM64_CONT_PTE_SHIFT
243 default 5 if ARM64_64K_PAGES
244 default 7 if ARM64_16K_PAGES
247 config ARM64_CONT_PMD_SHIFT
249 default 5 if ARM64_64K_PAGES
250 default 5 if ARM64_16K_PAGES
253 config ARCH_MMAP_RND_BITS_MIN
254 default 14 if ARM64_64K_PAGES
255 default 16 if ARM64_16K_PAGES
258 # max bits determined by the following formula:
259 # VA_BITS - PAGE_SHIFT - 3
260 config ARCH_MMAP_RND_BITS_MAX
261 default 19 if ARM64_VA_BITS=36
262 default 24 if ARM64_VA_BITS=39
263 default 27 if ARM64_VA_BITS=42
264 default 30 if ARM64_VA_BITS=47
265 default 29 if ARM64_VA_BITS=48 && ARM64_64K_PAGES
266 default 31 if ARM64_VA_BITS=48 && ARM64_16K_PAGES
267 default 33 if ARM64_VA_BITS=48
268 default 14 if ARM64_64K_PAGES
269 default 16 if ARM64_16K_PAGES
272 config ARCH_MMAP_RND_COMPAT_BITS_MIN
273 default 7 if ARM64_64K_PAGES
274 default 9 if ARM64_16K_PAGES
277 config ARCH_MMAP_RND_COMPAT_BITS_MAX
283 config STACKTRACE_SUPPORT
286 config ILLEGAL_POINTER_VALUE
288 default 0xdead000000000000
290 config LOCKDEP_SUPPORT
297 config GENERIC_BUG_RELATIVE_POINTERS
299 depends on GENERIC_BUG
301 config GENERIC_HWEIGHT
307 config GENERIC_CALIBRATE_DELAY
310 config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
316 config KERNEL_MODE_NEON
319 config FIX_EARLYCON_MEM
322 config PGTABLE_LEVELS
324 default 2 if ARM64_16K_PAGES && ARM64_VA_BITS_36
325 default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42
326 default 3 if ARM64_64K_PAGES && (ARM64_VA_BITS_48 || ARM64_VA_BITS_52)
327 default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39
328 default 3 if ARM64_16K_PAGES && ARM64_VA_BITS_47
329 default 4 if !ARM64_64K_PAGES && ARM64_VA_BITS_48
331 config ARCH_SUPPORTS_UPROBES
334 config ARCH_PROC_KCORE_TEXT
337 config BROKEN_GAS_INST
338 def_bool !$(as-instr,1:\n.inst 0\n.rept . - 1b\n\nnop\n.endr\n)
340 config KASAN_SHADOW_OFFSET
342 depends on KASAN_GENERIC || KASAN_SW_TAGS
343 default 0xdfff800000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && !KASAN_SW_TAGS
344 default 0xdfffc00000000000 if ARM64_VA_BITS_47 && !KASAN_SW_TAGS
345 default 0xdffffe0000000000 if ARM64_VA_BITS_42 && !KASAN_SW_TAGS
346 default 0xdfffffc000000000 if ARM64_VA_BITS_39 && !KASAN_SW_TAGS
347 default 0xdffffff800000000 if ARM64_VA_BITS_36 && !KASAN_SW_TAGS
348 default 0xefff800000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && KASAN_SW_TAGS
349 default 0xefffc00000000000 if ARM64_VA_BITS_47 && KASAN_SW_TAGS
350 default 0xeffffe0000000000 if ARM64_VA_BITS_42 && KASAN_SW_TAGS
351 default 0xefffffc000000000 if ARM64_VA_BITS_39 && KASAN_SW_TAGS
352 default 0xeffffff800000000 if ARM64_VA_BITS_36 && KASAN_SW_TAGS
353 default 0xffffffffffffffff
355 source "arch/arm64/Kconfig.platforms"
357 menu "Kernel Features"
359 menu "ARM errata workarounds via the alternatives framework"
361 config ARM64_WORKAROUND_CLEAN_CACHE
364 config ARM64_ERRATUM_826319
365 bool "Cortex-A53: 826319: System might deadlock if a write cannot complete until read data is accepted"
367 select ARM64_WORKAROUND_CLEAN_CACHE
369 This option adds an alternative code sequence to work around ARM
370 erratum 826319 on Cortex-A53 parts up to r0p2 with an AMBA 4 ACE or
371 AXI master interface and an L2 cache.
373 If a Cortex-A53 uses an AMBA AXI4 ACE interface to other processors
374 and is unable to accept a certain write via this interface, it will
375 not progress on read data presented on the read data channel and the
378 The workaround promotes data cache clean instructions to
379 data cache clean-and-invalidate.
380 Please note that this does not necessarily enable the workaround,
381 as it depends on the alternative framework, which will only patch
382 the kernel if an affected CPU is detected.
386 config ARM64_ERRATUM_827319
387 bool "Cortex-A53: 827319: Data cache clean instructions might cause overlapping transactions to the interconnect"
389 select ARM64_WORKAROUND_CLEAN_CACHE
391 This option adds an alternative code sequence to work around ARM
392 erratum 827319 on Cortex-A53 parts up to r0p2 with an AMBA 5 CHI
393 master interface and an L2 cache.
395 Under certain conditions this erratum can cause a clean line eviction
396 to occur at the same time as another transaction to the same address
397 on the AMBA 5 CHI interface, which can cause data corruption if the
398 interconnect reorders the two transactions.
400 The workaround promotes data cache clean instructions to
401 data cache clean-and-invalidate.
402 Please note that this does not necessarily enable the workaround,
403 as it depends on the alternative framework, which will only patch
404 the kernel if an affected CPU is detected.
408 config ARM64_ERRATUM_824069
409 bool "Cortex-A53: 824069: Cache line might not be marked as clean after a CleanShared snoop"
411 select ARM64_WORKAROUND_CLEAN_CACHE
413 This option adds an alternative code sequence to work around ARM
414 erratum 824069 on Cortex-A53 parts up to r0p2 when it is connected
415 to a coherent interconnect.
417 If a Cortex-A53 processor is executing a store or prefetch for
418 write instruction at the same time as a processor in another
419 cluster is executing a cache maintenance operation to the same
420 address, then this erratum might cause a clean cache line to be
421 incorrectly marked as dirty.
423 The workaround promotes data cache clean instructions to
424 data cache clean-and-invalidate.
425 Please note that this option does not necessarily enable the
426 workaround, as it depends on the alternative framework, which will
427 only patch the kernel if an affected CPU is detected.
431 config ARM64_ERRATUM_819472
432 bool "Cortex-A53: 819472: Store exclusive instructions might cause data corruption"
434 select ARM64_WORKAROUND_CLEAN_CACHE
436 This option adds an alternative code sequence to work around ARM
437 erratum 819472 on Cortex-A53 parts up to r0p1 with an L2 cache
438 present when it is connected to a coherent interconnect.
440 If the processor is executing a load and store exclusive sequence at
441 the same time as a processor in another cluster is executing a cache
442 maintenance operation to the same address, then this erratum might
443 cause data corruption.
445 The workaround promotes data cache clean instructions to
446 data cache clean-and-invalidate.
447 Please note that this does not necessarily enable the workaround,
448 as it depends on the alternative framework, which will only patch
449 the kernel if an affected CPU is detected.
453 config ARM64_ERRATUM_832075
454 bool "Cortex-A57: 832075: possible deadlock on mixing exclusive memory accesses with device loads"
457 This option adds an alternative code sequence to work around ARM
458 erratum 832075 on Cortex-A57 parts up to r1p2.
460 Affected Cortex-A57 parts might deadlock when exclusive load/store
461 instructions to Write-Back memory are mixed with Device loads.
463 The workaround is to promote device loads to use Load-Acquire
465 Please note that this does not necessarily enable the workaround,
466 as it depends on the alternative framework, which will only patch
467 the kernel if an affected CPU is detected.
471 config ARM64_ERRATUM_834220
472 bool "Cortex-A57: 834220: Stage 2 translation fault might be incorrectly reported in presence of a Stage 1 fault"
476 This option adds an alternative code sequence to work around ARM
477 erratum 834220 on Cortex-A57 parts up to r1p2.
479 Affected Cortex-A57 parts might report a Stage 2 translation
480 fault as the result of a Stage 1 fault for load crossing a
481 page boundary when there is a permission or device memory
482 alignment fault at Stage 1 and a translation fault at Stage 2.
484 The workaround is to verify that the Stage 1 translation
485 doesn't generate a fault before handling the Stage 2 fault.
486 Please note that this does not necessarily enable the workaround,
487 as it depends on the alternative framework, which will only patch
488 the kernel if an affected CPU is detected.
492 config ARM64_ERRATUM_845719
493 bool "Cortex-A53: 845719: a load might read incorrect data"
497 This option adds an alternative code sequence to work around ARM
498 erratum 845719 on Cortex-A53 parts up to r0p4.
500 When running a compat (AArch32) userspace on an affected Cortex-A53
501 part, a load at EL0 from a virtual address that matches the bottom 32
502 bits of the virtual address used by a recent load at (AArch64) EL1
503 might return incorrect data.
505 The workaround is to write the contextidr_el1 register on exception
506 return to a 32-bit task.
507 Please note that this does not necessarily enable the workaround,
508 as it depends on the alternative framework, which will only patch
509 the kernel if an affected CPU is detected.
513 config ARM64_ERRATUM_843419
514 bool "Cortex-A53: 843419: A load or store might access an incorrect address"
516 select ARM64_MODULE_PLTS if MODULES
518 This option links the kernel with '--fix-cortex-a53-843419' and
519 enables PLT support to replace certain ADRP instructions, which can
520 cause subsequent memory accesses to use an incorrect address on
521 Cortex-A53 parts up to r0p4.
525 config ARM64_LD_HAS_FIX_ERRATUM_843419
526 def_bool $(ld-option,--fix-cortex-a53-843419)
528 config ARM64_ERRATUM_1024718
529 bool "Cortex-A55: 1024718: Update of DBM/AP bits without break before make might result in incorrect update"
532 This option adds a workaround for ARM Cortex-A55 Erratum 1024718.
534 Affected Cortex-A55 cores (all revisions) could cause incorrect
535 update of the hardware dirty bit when the DBM/AP bits are updated
536 without a break-before-make. The workaround is to disable the usage
537 of hardware DBM locally on the affected cores. CPUs not affected by
538 this erratum will continue to use the feature.
542 config ARM64_ERRATUM_1418040
543 bool "Cortex-A76/Neoverse-N1: MRC read following MRRC read of specific Generic Timer in AArch32 might give incorrect result"
547 This option adds a workaround for ARM Cortex-A76/Neoverse-N1
548 errata 1188873 and 1418040.
550 Affected Cortex-A76/Neoverse-N1 cores (r0p0 to r3p1) could
551 cause register corruption when accessing the timer registers
552 from AArch32 userspace.
556 config ARM64_WORKAROUND_SPECULATIVE_AT
559 config ARM64_ERRATUM_1165522
560 bool "Cortex-A76: 1165522: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
562 select ARM64_WORKAROUND_SPECULATIVE_AT
564 This option adds a workaround for ARM Cortex-A76 erratum 1165522.
566 Affected Cortex-A76 cores (r0p0, r1p0, r2p0) could end-up with
567 corrupted TLBs by speculating an AT instruction during a guest
572 config ARM64_ERRATUM_1319367
573 bool "Cortex-A57/A72: 1319537: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
575 select ARM64_WORKAROUND_SPECULATIVE_AT
577 This option adds work arounds for ARM Cortex-A57 erratum 1319537
578 and A72 erratum 1319367
580 Cortex-A57 and A72 cores could end-up with corrupted TLBs by
581 speculating an AT instruction during a guest context switch.
585 config ARM64_ERRATUM_1530923
586 bool "Cortex-A55: 1530923: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
588 select ARM64_WORKAROUND_SPECULATIVE_AT
590 This option adds a workaround for ARM Cortex-A55 erratum 1530923.
592 Affected Cortex-A55 cores (r0p0, r0p1, r1p0, r2p0) could end-up with
593 corrupted TLBs by speculating an AT instruction during a guest
598 config ARM64_WORKAROUND_REPEAT_TLBI
601 config ARM64_ERRATUM_1286807
602 bool "Cortex-A76: Modification of the translation table for a virtual address might lead to read-after-read ordering violation"
604 select ARM64_WORKAROUND_REPEAT_TLBI
606 This option adds a workaround for ARM Cortex-A76 erratum 1286807.
608 On the affected Cortex-A76 cores (r0p0 to r3p0), if a virtual
609 address for a cacheable mapping of a location is being
610 accessed by a core while another core is remapping the virtual
611 address to a new physical page using the recommended
612 break-before-make sequence, then under very rare circumstances
613 TLBI+DSB completes before a read using the translation being
614 invalidated has been observed by other observers. The
615 workaround repeats the TLBI+DSB operation.
617 config ARM64_ERRATUM_1463225
618 bool "Cortex-A76: Software Step might prevent interrupt recognition"
621 This option adds a workaround for Arm Cortex-A76 erratum 1463225.
623 On the affected Cortex-A76 cores (r0p0 to r3p1), software stepping
624 of a system call instruction (SVC) can prevent recognition of
625 subsequent interrupts when software stepping is disabled in the
626 exception handler of the system call and either kernel debugging
627 is enabled or VHE is in use.
629 Work around the erratum by triggering a dummy step exception
630 when handling a system call from a task that is being stepped
631 in a VHE configuration of the kernel.
635 config ARM64_ERRATUM_1542419
636 bool "Neoverse-N1: workaround mis-ordering of instruction fetches"
639 This option adds a workaround for ARM Neoverse-N1 erratum
642 Affected Neoverse-N1 cores could execute a stale instruction when
643 modified by another CPU. The workaround depends on a firmware
646 Workaround the issue by hiding the DIC feature from EL0. This
647 forces user-space to perform cache maintenance.
651 config ARM64_ERRATUM_1508412
652 bool "Cortex-A77: 1508412: workaround deadlock on sequence of NC/Device load and store exclusive or PAR read"
655 This option adds a workaround for Arm Cortex-A77 erratum 1508412.
657 Affected Cortex-A77 cores (r0p0, r1p0) could deadlock on a sequence
658 of a store-exclusive or read of PAR_EL1 and a load with device or
659 non-cacheable memory attributes. The workaround depends on a firmware
662 KVM guests must also have the workaround implemented or they can
665 Work around the issue by inserting DMB SY barriers around PAR_EL1
666 register reads and warning KVM users. The DMB barrier is sufficient
667 to prevent a speculative PAR_EL1 read.
671 config ARM64_WORKAROUND_TRBE_OVERWRITE_FILL_MODE
674 config ARM64_ERRATUM_2051678
675 bool "Cortex-A510: 2051678: disable Hardware Update of the page table dirty bit"
677 This options adds the workaround for ARM Cortex-A510 erratum ARM64_ERRATUM_2051678.
678 Affected Coretex-A510 might not respect the ordering rules for
679 hardware update of the page table's dirty bit. The workaround
680 is to not enable the feature on affected CPUs.
684 config ARM64_ERRATUM_2077057
685 bool "Cortex-A510: 2077057: workaround software-step corrupting SPSR_EL2"
687 This option adds the workaround for ARM Cortex-A510 erratum 2077057.
688 Affected Cortex-A510 may corrupt SPSR_EL2 when the a step exception is
689 expected, but a Pointer Authentication trap is taken instead. The
690 erratum causes SPSR_EL1 to be copied to SPSR_EL2, which could allow
691 EL1 to cause a return to EL2 with a guest controlled ELR_EL2.
693 This can only happen when EL2 is stepping EL1.
695 When these conditions occur, the SPSR_EL2 value is unchanged from the
696 previous guest entry, and can be restored from the in-memory copy.
700 config ARM64_ERRATUM_2119858
701 bool "Cortex-A710/X2: 2119858: workaround TRBE overwriting trace data in FILL mode"
703 depends on CORESIGHT_TRBE
704 select ARM64_WORKAROUND_TRBE_OVERWRITE_FILL_MODE
706 This option adds the workaround for ARM Cortex-A710/X2 erratum 2119858.
708 Affected Cortex-A710/X2 cores could overwrite up to 3 cache lines of trace
709 data at the base of the buffer (pointed to by TRBASER_EL1) in FILL mode in
710 the event of a WRAP event.
712 Work around the issue by always making sure we move the TRBPTR_EL1 by
713 256 bytes before enabling the buffer and filling the first 256 bytes of
714 the buffer with ETM ignore packets upon disabling.
718 config ARM64_ERRATUM_2139208
719 bool "Neoverse-N2: 2139208: workaround TRBE overwriting trace data in FILL mode"
721 depends on CORESIGHT_TRBE
722 select ARM64_WORKAROUND_TRBE_OVERWRITE_FILL_MODE
724 This option adds the workaround for ARM Neoverse-N2 erratum 2139208.
726 Affected Neoverse-N2 cores could overwrite up to 3 cache lines of trace
727 data at the base of the buffer (pointed to by TRBASER_EL1) in FILL mode in
728 the event of a WRAP event.
730 Work around the issue by always making sure we move the TRBPTR_EL1 by
731 256 bytes before enabling the buffer and filling the first 256 bytes of
732 the buffer with ETM ignore packets upon disabling.
736 config ARM64_WORKAROUND_TSB_FLUSH_FAILURE
739 config ARM64_ERRATUM_2054223
740 bool "Cortex-A710: 2054223: workaround TSB instruction failing to flush trace"
742 select ARM64_WORKAROUND_TSB_FLUSH_FAILURE
744 Enable workaround for ARM Cortex-A710 erratum 2054223
746 Affected cores may fail to flush the trace data on a TSB instruction, when
747 the PE is in trace prohibited state. This will cause losing a few bytes
750 Workaround is to issue two TSB consecutively on affected cores.
754 config ARM64_ERRATUM_2067961
755 bool "Neoverse-N2: 2067961: workaround TSB instruction failing to flush trace"
757 select ARM64_WORKAROUND_TSB_FLUSH_FAILURE
759 Enable workaround for ARM Neoverse-N2 erratum 2067961
761 Affected cores may fail to flush the trace data on a TSB instruction, when
762 the PE is in trace prohibited state. This will cause losing a few bytes
765 Workaround is to issue two TSB consecutively on affected cores.
769 config ARM64_WORKAROUND_TRBE_WRITE_OUT_OF_RANGE
772 config ARM64_ERRATUM_2253138
773 bool "Neoverse-N2: 2253138: workaround TRBE writing to address out-of-range"
774 depends on CORESIGHT_TRBE
776 select ARM64_WORKAROUND_TRBE_WRITE_OUT_OF_RANGE
778 This option adds the workaround for ARM Neoverse-N2 erratum 2253138.
780 Affected Neoverse-N2 cores might write to an out-of-range address, not reserved
781 for TRBE. Under some conditions, the TRBE might generate a write to the next
782 virtually addressed page following the last page of the TRBE address space
783 (i.e., the TRBLIMITR_EL1.LIMIT), instead of wrapping around to the base.
785 Work around this in the driver by always making sure that there is a
786 page beyond the TRBLIMITR_EL1.LIMIT, within the space allowed for the TRBE.
790 config ARM64_ERRATUM_2224489
791 bool "Cortex-A710/X2: 2224489: workaround TRBE writing to address out-of-range"
792 depends on CORESIGHT_TRBE
794 select ARM64_WORKAROUND_TRBE_WRITE_OUT_OF_RANGE
796 This option adds the workaround for ARM Cortex-A710/X2 erratum 2224489.
798 Affected Cortex-A710/X2 cores might write to an out-of-range address, not reserved
799 for TRBE. Under some conditions, the TRBE might generate a write to the next
800 virtually addressed page following the last page of the TRBE address space
801 (i.e., the TRBLIMITR_EL1.LIMIT), instead of wrapping around to the base.
803 Work around this in the driver by always making sure that there is a
804 page beyond the TRBLIMITR_EL1.LIMIT, within the space allowed for the TRBE.
808 config ARM64_ERRATUM_2064142
809 bool "Cortex-A510: 2064142: workaround TRBE register writes while disabled"
810 depends on COMPILE_TEST # Until the CoreSight TRBE driver changes are in
813 This option adds the workaround for ARM Cortex-A510 erratum 2064142.
815 Affected Cortex-A510 core might fail to write into system registers after the
816 TRBE has been disabled. Under some conditions after the TRBE has been disabled
817 writes into TRBE registers TRBLIMITR_EL1, TRBPTR_EL1, TRBBASER_EL1, TRBSR_EL1,
818 and TRBTRG_EL1 will be ignored and will not be effected.
820 Work around this in the driver by executing TSB CSYNC and DSB after collection
821 is stopped and before performing a system register write to one of the affected
826 config ARM64_ERRATUM_2038923
827 bool "Cortex-A510: 2038923: workaround TRBE corruption with enable"
828 depends on COMPILE_TEST # Until the CoreSight TRBE driver changes are in
831 This option adds the workaround for ARM Cortex-A510 erratum 2038923.
833 Affected Cortex-A510 core might cause an inconsistent view on whether trace is
834 prohibited within the CPU. As a result, the trace buffer or trace buffer state
835 might be corrupted. This happens after TRBE buffer has been enabled by setting
836 TRBLIMITR_EL1.E, followed by just a single context synchronization event before
837 execution changes from a context, in which trace is prohibited to one where it
838 isn't, or vice versa. In these mentioned conditions, the view of whether trace
839 is prohibited is inconsistent between parts of the CPU, and the trace buffer or
840 the trace buffer state might be corrupted.
842 Work around this in the driver by preventing an inconsistent view of whether the
843 trace is prohibited or not based on TRBLIMITR_EL1.E by immediately following a
844 change to TRBLIMITR_EL1.E with at least one ISB instruction before an ERET, or
845 two ISB instructions if no ERET is to take place.
849 config ARM64_ERRATUM_1902691
850 bool "Cortex-A510: 1902691: workaround TRBE trace corruption"
851 depends on COMPILE_TEST # Until the CoreSight TRBE driver changes are in
854 This option adds the workaround for ARM Cortex-A510 erratum 1902691.
856 Affected Cortex-A510 core might cause trace data corruption, when being written
857 into the memory. Effectively TRBE is broken and hence cannot be used to capture
860 Work around this problem in the driver by just preventing TRBE initialization on
861 affected cpus. The firmware must have disabled the access to TRBE for the kernel
862 on such implementations. This will cover the kernel for any firmware that doesn't
867 config CAVIUM_ERRATUM_22375
868 bool "Cavium erratum 22375, 24313"
871 Enable workaround for errata 22375 and 24313.
873 This implements two gicv3-its errata workarounds for ThunderX. Both
874 with a small impact affecting only ITS table allocation.
876 erratum 22375: only alloc 8MB table size
877 erratum 24313: ignore memory access type
879 The fixes are in ITS initialization and basically ignore memory access
880 type and table size provided by the TYPER and BASER registers.
884 config CAVIUM_ERRATUM_23144
885 bool "Cavium erratum 23144: ITS SYNC hang on dual socket system"
889 ITS SYNC command hang for cross node io and collections/cpu mapping.
893 config CAVIUM_ERRATUM_23154
894 bool "Cavium errata 23154 and 38545: GICv3 lacks HW synchronisation"
897 The ThunderX GICv3 implementation requires a modified version for
898 reading the IAR status to ensure data synchronization
899 (access to icc_iar1_el1 is not sync'ed before and after).
901 It also suffers from erratum 38545 (also present on Marvell's
902 OcteonTX and OcteonTX2), resulting in deactivated interrupts being
903 spuriously presented to the CPU interface.
907 config CAVIUM_ERRATUM_27456
908 bool "Cavium erratum 27456: Broadcast TLBI instructions may cause icache corruption"
911 On ThunderX T88 pass 1.x through 2.1 parts, broadcast TLBI
912 instructions may cause the icache to become corrupted if it
913 contains data for a non-current ASID. The fix is to
914 invalidate the icache when changing the mm context.
918 config CAVIUM_ERRATUM_30115
919 bool "Cavium erratum 30115: Guest may disable interrupts in host"
922 On ThunderX T88 pass 1.x through 2.2, T81 pass 1.0 through
923 1.2, and T83 Pass 1.0, KVM guest execution may disable
924 interrupts in host. Trapping both GICv3 group-0 and group-1
925 accesses sidesteps the issue.
929 config CAVIUM_TX2_ERRATUM_219
930 bool "Cavium ThunderX2 erratum 219: PRFM between TTBR change and ISB fails"
933 On Cavium ThunderX2, a load, store or prefetch instruction between a
934 TTBR update and the corresponding context synchronizing operation can
935 cause a spurious Data Abort to be delivered to any hardware thread in
938 Work around the issue by avoiding the problematic code sequence and
939 trapping KVM guest TTBRx_EL1 writes to EL2 when SMT is enabled. The
940 trap handler performs the corresponding register access, skips the
941 instruction and ensures context synchronization by virtue of the
946 config FUJITSU_ERRATUM_010001
947 bool "Fujitsu-A64FX erratum E#010001: Undefined fault may occur wrongly"
950 This option adds a workaround for Fujitsu-A64FX erratum E#010001.
951 On some variants of the Fujitsu-A64FX cores ver(1.0, 1.1), memory
952 accesses may cause undefined fault (Data abort, DFSC=0b111111).
953 This fault occurs under a specific hardware condition when a
954 load/store instruction performs an address translation using:
955 case-1 TTBR0_EL1 with TCR_EL1.NFD0 == 1.
956 case-2 TTBR0_EL2 with TCR_EL2.NFD0 == 1.
957 case-3 TTBR1_EL1 with TCR_EL1.NFD1 == 1.
958 case-4 TTBR1_EL2 with TCR_EL2.NFD1 == 1.
960 The workaround is to ensure these bits are clear in TCR_ELx.
961 The workaround only affects the Fujitsu-A64FX.
965 config HISILICON_ERRATUM_161600802
966 bool "Hip07 161600802: Erroneous redistributor VLPI base"
969 The HiSilicon Hip07 SoC uses the wrong redistributor base
970 when issued ITS commands such as VMOVP and VMAPP, and requires
971 a 128kB offset to be applied to the target address in this commands.
975 config QCOM_FALKOR_ERRATUM_1003
976 bool "Falkor E1003: Incorrect translation due to ASID change"
979 On Falkor v1, an incorrect ASID may be cached in the TLB when ASID
980 and BADDR are changed together in TTBRx_EL1. Since we keep the ASID
981 in TTBR1_EL1, this situation only occurs in the entry trampoline and
982 then only for entries in the walk cache, since the leaf translation
983 is unchanged. Work around the erratum by invalidating the walk cache
984 entries for the trampoline before entering the kernel proper.
986 config QCOM_FALKOR_ERRATUM_1009
987 bool "Falkor E1009: Prematurely complete a DSB after a TLBI"
989 select ARM64_WORKAROUND_REPEAT_TLBI
991 On Falkor v1, the CPU may prematurely complete a DSB following a
992 TLBI xxIS invalidate maintenance operation. Repeat the TLBI operation
993 one more time to fix the issue.
997 config QCOM_QDF2400_ERRATUM_0065
998 bool "QDF2400 E0065: Incorrect GITS_TYPER.ITT_Entry_size"
1001 On Qualcomm Datacenter Technologies QDF2400 SoC, ITS hardware reports
1002 ITE size incorrectly. The GITS_TYPER.ITT_Entry_size field should have
1003 been indicated as 16Bytes (0xf), not 8Bytes (0x7).
1007 config QCOM_FALKOR_ERRATUM_E1041
1008 bool "Falkor E1041: Speculative instruction fetches might cause errant memory access"
1011 Falkor CPU may speculatively fetch instructions from an improper
1012 memory location when MMU translation is changed from SCTLR_ELn[M]=1
1013 to SCTLR_ELn[M]=0. Prefix an ISB instruction to fix the problem.
1017 config NVIDIA_CARMEL_CNP_ERRATUM
1018 bool "NVIDIA Carmel CNP: CNP on Carmel semantically different than ARM cores"
1021 If CNP is enabled on Carmel cores, non-sharable TLBIs on a core will not
1022 invalidate shared TLB entries installed by a different core, as it would
1023 on standard ARM cores.
1027 config SOCIONEXT_SYNQUACER_PREITS
1028 bool "Socionext Synquacer: Workaround for GICv3 pre-ITS"
1031 Socionext Synquacer SoCs implement a separate h/w block to generate
1032 MSI doorbell writes with non-zero values for the device ID.
1041 default ARM64_4K_PAGES
1043 Page size (translation granule) configuration.
1045 config ARM64_4K_PAGES
1048 This feature enables 4KB pages support.
1050 config ARM64_16K_PAGES
1053 The system will use 16KB pages support. AArch32 emulation
1054 requires applications compiled with 16K (or a multiple of 16K)
1057 config ARM64_64K_PAGES
1060 This feature enables 64KB pages support (4KB by default)
1061 allowing only two levels of page tables and faster TLB
1062 look-up. AArch32 emulation requires applications compiled
1063 with 64K aligned segments.
1068 prompt "Virtual address space size"
1069 default ARM64_VA_BITS_39 if ARM64_4K_PAGES
1070 default ARM64_VA_BITS_47 if ARM64_16K_PAGES
1071 default ARM64_VA_BITS_42 if ARM64_64K_PAGES
1073 Allows choosing one of multiple possible virtual address
1074 space sizes. The level of translation table is determined by
1075 a combination of page size and virtual address space size.
1077 config ARM64_VA_BITS_36
1078 bool "36-bit" if EXPERT
1079 depends on ARM64_16K_PAGES
1081 config ARM64_VA_BITS_39
1083 depends on ARM64_4K_PAGES
1085 config ARM64_VA_BITS_42
1087 depends on ARM64_64K_PAGES
1089 config ARM64_VA_BITS_47
1091 depends on ARM64_16K_PAGES
1093 config ARM64_VA_BITS_48
1096 config ARM64_VA_BITS_52
1098 depends on ARM64_64K_PAGES && (ARM64_PAN || !ARM64_SW_TTBR0_PAN)
1100 Enable 52-bit virtual addressing for userspace when explicitly
1101 requested via a hint to mmap(). The kernel will also use 52-bit
1102 virtual addresses for its own mappings (provided HW support for
1103 this feature is available, otherwise it reverts to 48-bit).
1105 NOTE: Enabling 52-bit virtual addressing in conjunction with
1106 ARMv8.3 Pointer Authentication will result in the PAC being
1107 reduced from 7 bits to 3 bits, which may have a significant
1108 impact on its susceptibility to brute-force attacks.
1110 If unsure, select 48-bit virtual addressing instead.
1114 config ARM64_FORCE_52BIT
1115 bool "Force 52-bit virtual addresses for userspace"
1116 depends on ARM64_VA_BITS_52 && EXPERT
1118 For systems with 52-bit userspace VAs enabled, the kernel will attempt
1119 to maintain compatibility with older software by providing 48-bit VAs
1120 unless a hint is supplied to mmap.
1122 This configuration option disables the 48-bit compatibility logic, and
1123 forces all userspace addresses to be 52-bit on HW that supports it. One
1124 should only enable this configuration option for stress testing userspace
1125 memory management code. If unsure say N here.
1127 config ARM64_VA_BITS
1129 default 36 if ARM64_VA_BITS_36
1130 default 39 if ARM64_VA_BITS_39
1131 default 42 if ARM64_VA_BITS_42
1132 default 47 if ARM64_VA_BITS_47
1133 default 48 if ARM64_VA_BITS_48
1134 default 52 if ARM64_VA_BITS_52
1137 prompt "Physical address space size"
1138 default ARM64_PA_BITS_48
1140 Choose the maximum physical address range that the kernel will
1143 config ARM64_PA_BITS_48
1146 config ARM64_PA_BITS_52
1147 bool "52-bit (ARMv8.2)"
1148 depends on ARM64_64K_PAGES
1149 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
1151 Enable support for a 52-bit physical address space, introduced as
1152 part of the ARMv8.2-LPA extension.
1154 With this enabled, the kernel will also continue to work on CPUs that
1155 do not support ARMv8.2-LPA, but with some added memory overhead (and
1156 minor performance overhead).
1160 config ARM64_PA_BITS
1162 default 48 if ARM64_PA_BITS_48
1163 default 52 if ARM64_PA_BITS_52
1167 default CPU_LITTLE_ENDIAN
1169 Select the endianness of data accesses performed by the CPU. Userspace
1170 applications will need to be compiled and linked for the endianness
1171 that is selected here.
1173 config CPU_BIG_ENDIAN
1174 bool "Build big-endian kernel"
1175 depends on !LD_IS_LLD || LLD_VERSION >= 130000
1177 Say Y if you plan on running a kernel with a big-endian userspace.
1179 config CPU_LITTLE_ENDIAN
1180 bool "Build little-endian kernel"
1182 Say Y if you plan on running a kernel with a little-endian userspace.
1183 This is usually the case for distributions targeting arm64.
1188 bool "Multi-core scheduler support"
1190 Multi-core scheduler support improves the CPU scheduler's decision
1191 making when dealing with multi-core CPU chips at a cost of slightly
1192 increased overhead in some places. If unsure say N here.
1194 config SCHED_CLUSTER
1195 bool "Cluster scheduler support"
1197 Cluster scheduler support improves the CPU scheduler's decision
1198 making when dealing with machines that have clusters of CPUs.
1199 Cluster usually means a couple of CPUs which are placed closely
1200 by sharing mid-level caches, last-level cache tags or internal
1204 bool "SMT scheduler support"
1206 Improves the CPU scheduler's decision making when dealing with
1207 MultiThreading at a cost of slightly increased overhead in some
1208 places. If unsure say N here.
1211 int "Maximum number of CPUs (2-4096)"
1216 bool "Support for hot-pluggable CPUs"
1217 select GENERIC_IRQ_MIGRATION
1219 Say Y here to experiment with turning CPUs off and on. CPUs
1220 can be controlled through /sys/devices/system/cpu.
1222 # Common NUMA Features
1224 bool "NUMA Memory Allocation and Scheduler Support"
1225 select GENERIC_ARCH_NUMA
1226 select ACPI_NUMA if ACPI
1228 select HAVE_SETUP_PER_CPU_AREA
1229 select NEED_PER_CPU_EMBED_FIRST_CHUNK
1230 select NEED_PER_CPU_PAGE_FIRST_CHUNK
1231 select USE_PERCPU_NUMA_NODE_ID
1233 Enable NUMA (Non-Uniform Memory Access) support.
1235 The kernel will try to allocate memory used by a CPU on the
1236 local memory of the CPU and add some more
1237 NUMA awareness to the kernel.
1240 int "Maximum NUMA Nodes (as a power of 2)"
1245 Specify the maximum number of NUMA Nodes available on the target
1246 system. Increases memory reserved to accommodate various tables.
1248 source "kernel/Kconfig.hz"
1250 config ARCH_SPARSEMEM_ENABLE
1252 select SPARSEMEM_VMEMMAP_ENABLE
1253 select SPARSEMEM_VMEMMAP
1255 config HW_PERF_EVENTS
1259 config ARCH_HAS_FILTER_PGPROT
1262 # Supported by clang >= 7.0
1263 config CC_HAVE_SHADOW_CALL_STACK
1264 def_bool $(cc-option, -fsanitize=shadow-call-stack -ffixed-x18)
1267 bool "Enable paravirtualization code"
1269 This changes the kernel so it can modify itself when it is run
1270 under a hypervisor, potentially improving performance significantly
1271 over full virtualization.
1273 config PARAVIRT_TIME_ACCOUNTING
1274 bool "Paravirtual steal time accounting"
1277 Select this option to enable fine granularity task steal time
1278 accounting. Time spent executing other tasks in parallel with
1279 the current vCPU is discounted from the vCPU power. To account for
1280 that, there can be a small performance impact.
1282 If in doubt, say N here.
1285 depends on PM_SLEEP_SMP
1287 bool "kexec system call"
1289 kexec is a system call that implements the ability to shutdown your
1290 current kernel, and to start another kernel. It is like a reboot
1291 but it is independent of the system firmware. And like a reboot
1292 you can start any kernel with it, not just Linux.
1295 bool "kexec file based system call"
1297 select HAVE_IMA_KEXEC if IMA
1299 This is new version of kexec system call. This system call is
1300 file based and takes file descriptors as system call argument
1301 for kernel and initramfs as opposed to list of segments as
1302 accepted by previous system call.
1305 bool "Verify kernel signature during kexec_file_load() syscall"
1306 depends on KEXEC_FILE
1308 Select this option to verify a signature with loaded kernel
1309 image. If configured, any attempt of loading a image without
1310 valid signature will fail.
1312 In addition to that option, you need to enable signature
1313 verification for the corresponding kernel image type being
1314 loaded in order for this to work.
1316 config KEXEC_IMAGE_VERIFY_SIG
1317 bool "Enable Image signature verification support"
1319 depends on KEXEC_SIG
1320 depends on EFI && SIGNED_PE_FILE_VERIFICATION
1322 Enable Image signature verification support.
1324 comment "Support for PE file signature verification disabled"
1325 depends on KEXEC_SIG
1326 depends on !EFI || !SIGNED_PE_FILE_VERIFICATION
1329 bool "Build kdump crash kernel"
1331 Generate crash dump after being started by kexec. This should
1332 be normally only set in special crash dump kernels which are
1333 loaded in the main kernel with kexec-tools into a specially
1334 reserved region and then later executed after a crash by
1337 For more details see Documentation/admin-guide/kdump/kdump.rst
1341 depends on HIBERNATION || KEXEC_CORE
1348 bool "Xen guest support on ARM64"
1349 depends on ARM64 && OF
1353 Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64.
1355 config FORCE_MAX_ZONEORDER
1357 default "14" if ARM64_64K_PAGES
1358 default "12" if ARM64_16K_PAGES
1361 The kernel memory allocator divides physically contiguous memory
1362 blocks into "zones", where each zone is a power of two number of
1363 pages. This option selects the largest power of two that the kernel
1364 keeps in the memory allocator. If you need to allocate very large
1365 blocks of physically contiguous memory, then you may need to
1366 increase this value.
1368 This config option is actually maximum order plus one. For example,
1369 a value of 11 means that the largest free memory block is 2^10 pages.
1371 We make sure that we can allocate upto a HugePage size for each configuration.
1373 MAX_ORDER = (PMD_SHIFT - PAGE_SHIFT) + 1 => PAGE_SHIFT - 2
1375 However for 4K, we choose a higher default value, 11 as opposed to 10, giving us
1376 4M allocations matching the default size used by generic code.
1378 config UNMAP_KERNEL_AT_EL0
1379 bool "Unmap kernel when running in userspace (aka \"KAISER\")" if EXPERT
1382 Speculation attacks against some high-performance processors can
1383 be used to bypass MMU permission checks and leak kernel data to
1384 userspace. This can be defended against by unmapping the kernel
1385 when running in userspace, mapping it back in on exception entry
1386 via a trampoline page in the vector table.
1390 config MITIGATE_SPECTRE_BRANCH_HISTORY
1391 bool "Mitigate Spectre style attacks against branch history" if EXPERT
1394 Speculation attacks against some high-performance processors can
1395 make use of branch history to influence future speculation.
1396 When taking an exception from user-space, a sequence of branches
1397 or a firmware call overwrites the branch history.
1399 config RODATA_FULL_DEFAULT_ENABLED
1400 bool "Apply r/o permissions of VM areas also to their linear aliases"
1403 Apply read-only attributes of VM areas to the linear alias of
1404 the backing pages as well. This prevents code or read-only data
1405 from being modified (inadvertently or intentionally) via another
1406 mapping of the same memory page. This additional enhancement can
1407 be turned off at runtime by passing rodata=[off|on] (and turned on
1408 with rodata=full if this option is set to 'n')
1410 This requires the linear region to be mapped down to pages,
1411 which may adversely affect performance in some cases.
1413 config ARM64_SW_TTBR0_PAN
1414 bool "Emulate Privileged Access Never using TTBR0_EL1 switching"
1416 Enabling this option prevents the kernel from accessing
1417 user-space memory directly by pointing TTBR0_EL1 to a reserved
1418 zeroed area and reserved ASID. The user access routines
1419 restore the valid TTBR0_EL1 temporarily.
1421 config ARM64_TAGGED_ADDR_ABI
1422 bool "Enable the tagged user addresses syscall ABI"
1425 When this option is enabled, user applications can opt in to a
1426 relaxed ABI via prctl() allowing tagged addresses to be passed
1427 to system calls as pointer arguments. For details, see
1428 Documentation/arm64/tagged-address-abi.rst.
1431 bool "Kernel support for 32-bit EL0"
1432 depends on ARM64_4K_PAGES || EXPERT
1434 select OLD_SIGSUSPEND3
1435 select COMPAT_OLD_SIGACTION
1437 This option enables support for a 32-bit EL0 running under a 64-bit
1438 kernel at EL1. AArch32-specific components such as system calls,
1439 the user helper functions, VFP support and the ptrace interface are
1440 handled appropriately by the kernel.
1442 If you use a page size other than 4KB (i.e, 16KB or 64KB), please be aware
1443 that you will only be able to execute AArch32 binaries that were compiled
1444 with page size aligned segments.
1446 If you want to execute 32-bit userspace applications, say Y.
1450 config KUSER_HELPERS
1451 bool "Enable kuser helpers page for 32-bit applications"
1454 Warning: disabling this option may break 32-bit user programs.
1456 Provide kuser helpers to compat tasks. The kernel provides
1457 helper code to userspace in read only form at a fixed location
1458 to allow userspace to be independent of the CPU type fitted to
1459 the system. This permits binaries to be run on ARMv4 through
1460 to ARMv8 without modification.
1462 See Documentation/arm/kernel_user_helpers.rst for details.
1464 However, the fixed address nature of these helpers can be used
1465 by ROP (return orientated programming) authors when creating
1468 If all of the binaries and libraries which run on your platform
1469 are built specifically for your platform, and make no use of
1470 these helpers, then you can turn this option off to hinder
1471 such exploits. However, in that case, if a binary or library
1472 relying on those helpers is run, it will not function correctly.
1474 Say N here only if you are absolutely certain that you do not
1475 need these helpers; otherwise, the safe option is to say Y.
1478 bool "Enable vDSO for 32-bit applications"
1479 depends on !CPU_BIG_ENDIAN
1480 depends on (CC_IS_CLANG && LD_IS_LLD) || "$(CROSS_COMPILE_COMPAT)" != ""
1481 select GENERIC_COMPAT_VDSO
1484 Place in the process address space of 32-bit applications an
1485 ELF shared object providing fast implementations of gettimeofday
1488 You must have a 32-bit build of glibc 2.22 or later for programs
1489 to seamlessly take advantage of this.
1491 config THUMB2_COMPAT_VDSO
1492 bool "Compile the 32-bit vDSO for Thumb-2 mode" if EXPERT
1493 depends on COMPAT_VDSO
1496 Compile the compat vDSO with '-mthumb -fomit-frame-pointer' if y,
1497 otherwise with '-marm'.
1499 menuconfig ARMV8_DEPRECATED
1500 bool "Emulate deprecated/obsolete ARMv8 instructions"
1503 Legacy software support may require certain instructions
1504 that have been deprecated or obsoleted in the architecture.
1506 Enable this config to enable selective emulation of these
1513 config SWP_EMULATION
1514 bool "Emulate SWP/SWPB instructions"
1516 ARMv8 obsoletes the use of A32 SWP/SWPB instructions such that
1517 they are always undefined. Say Y here to enable software
1518 emulation of these instructions for userspace using LDXR/STXR.
1519 This feature can be controlled at runtime with the abi.swp
1520 sysctl which is disabled by default.
1522 In some older versions of glibc [<=2.8] SWP is used during futex
1523 trylock() operations with the assumption that the code will not
1524 be preempted. This invalid assumption may be more likely to fail
1525 with SWP emulation enabled, leading to deadlock of the user
1528 NOTE: when accessing uncached shared regions, LDXR/STXR rely
1529 on an external transaction monitoring block called a global
1530 monitor to maintain update atomicity. If your system does not
1531 implement a global monitor, this option can cause programs that
1532 perform SWP operations to uncached memory to deadlock.
1536 config CP15_BARRIER_EMULATION
1537 bool "Emulate CP15 Barrier instructions"
1539 The CP15 barrier instructions - CP15ISB, CP15DSB, and
1540 CP15DMB - are deprecated in ARMv8 (and ARMv7). It is
1541 strongly recommended to use the ISB, DSB, and DMB
1542 instructions instead.
1544 Say Y here to enable software emulation of these
1545 instructions for AArch32 userspace code. When this option is
1546 enabled, CP15 barrier usage is traced which can help
1547 identify software that needs updating. This feature can be
1548 controlled at runtime with the abi.cp15_barrier sysctl.
1552 config SETEND_EMULATION
1553 bool "Emulate SETEND instruction"
1555 The SETEND instruction alters the data-endianness of the
1556 AArch32 EL0, and is deprecated in ARMv8.
1558 Say Y here to enable software emulation of the instruction
1559 for AArch32 userspace code. This feature can be controlled
1560 at runtime with the abi.setend sysctl.
1562 Note: All the cpus on the system must have mixed endian support at EL0
1563 for this feature to be enabled. If a new CPU - which doesn't support mixed
1564 endian - is hotplugged in after this feature has been enabled, there could
1565 be unexpected results in the applications.
1572 menu "ARMv8.1 architectural features"
1574 config ARM64_HW_AFDBM
1575 bool "Support for hardware updates of the Access and Dirty page flags"
1578 The ARMv8.1 architecture extensions introduce support for
1579 hardware updates of the access and dirty information in page
1580 table entries. When enabled in TCR_EL1 (HA and HD bits) on
1581 capable processors, accesses to pages with PTE_AF cleared will
1582 set this bit instead of raising an access flag fault.
1583 Similarly, writes to read-only pages with the DBM bit set will
1584 clear the read-only bit (AP[2]) instead of raising a
1587 Kernels built with this configuration option enabled continue
1588 to work on pre-ARMv8.1 hardware and the performance impact is
1589 minimal. If unsure, say Y.
1592 bool "Enable support for Privileged Access Never (PAN)"
1595 Privileged Access Never (PAN; part of the ARMv8.1 Extensions)
1596 prevents the kernel or hypervisor from accessing user-space (EL0)
1599 Choosing this option will cause any unprotected (not using
1600 copy_to_user et al) memory access to fail with a permission fault.
1602 The feature is detected at runtime, and will remain as a 'nop'
1603 instruction if the cpu does not implement the feature.
1606 def_bool $(as-instr,.arch_extension rcpc)
1608 config AS_HAS_LSE_ATOMICS
1609 def_bool $(as-instr,.arch_extension lse)
1611 config ARM64_LSE_ATOMICS
1613 default ARM64_USE_LSE_ATOMICS
1614 depends on AS_HAS_LSE_ATOMICS
1616 config ARM64_USE_LSE_ATOMICS
1617 bool "Atomic instructions"
1618 depends on JUMP_LABEL
1621 As part of the Large System Extensions, ARMv8.1 introduces new
1622 atomic instructions that are designed specifically to scale in
1625 Say Y here to make use of these instructions for the in-kernel
1626 atomic routines. This incurs a small overhead on CPUs that do
1627 not support these instructions and requires the kernel to be
1628 built with binutils >= 2.25 in order for the new instructions
1633 menu "ARMv8.2 architectural features"
1635 config AS_HAS_ARMV8_2
1636 def_bool $(cc-option,-Wa$(comma)-march=armv8.2-a)
1639 def_bool $(as-instr,.arch armv8.2-a+sha3)
1642 bool "Enable support for persistent memory"
1643 select ARCH_HAS_PMEM_API
1644 select ARCH_HAS_UACCESS_FLUSHCACHE
1646 Say Y to enable support for the persistent memory API based on the
1647 ARMv8.2 DCPoP feature.
1649 The feature is detected at runtime, and the kernel will use DC CVAC
1650 operations if DC CVAP is not supported (following the behaviour of
1651 DC CVAP itself if the system does not define a point of persistence).
1653 config ARM64_RAS_EXTN
1654 bool "Enable support for RAS CPU Extensions"
1657 CPUs that support the Reliability, Availability and Serviceability
1658 (RAS) Extensions, part of ARMv8.2 are able to track faults and
1659 errors, classify them and report them to software.
1661 On CPUs with these extensions system software can use additional
1662 barriers to determine if faults are pending and read the
1663 classification from a new set of registers.
1665 Selecting this feature will allow the kernel to use these barriers
1666 and access the new registers if the system supports the extension.
1667 Platform RAS features may additionally depend on firmware support.
1670 bool "Enable support for Common Not Private (CNP) translations"
1672 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
1674 Common Not Private (CNP) allows translation table entries to
1675 be shared between different PEs in the same inner shareable
1676 domain, so the hardware can use this fact to optimise the
1677 caching of such entries in the TLB.
1679 Selecting this option allows the CNP feature to be detected
1680 at runtime, and does not affect PEs that do not implement
1685 menu "ARMv8.3 architectural features"
1687 config ARM64_PTR_AUTH
1688 bool "Enable support for pointer authentication"
1691 Pointer authentication (part of the ARMv8.3 Extensions) provides
1692 instructions for signing and authenticating pointers against secret
1693 keys, which can be used to mitigate Return Oriented Programming (ROP)
1696 This option enables these instructions at EL0 (i.e. for userspace).
1697 Choosing this option will cause the kernel to initialise secret keys
1698 for each process at exec() time, with these keys being
1699 context-switched along with the process.
1701 The feature is detected at runtime. If the feature is not present in
1702 hardware it will not be advertised to userspace/KVM guest nor will it
1705 If the feature is present on the boot CPU but not on a late CPU, then
1706 the late CPU will be parked. Also, if the boot CPU does not have
1707 address auth and the late CPU has then the late CPU will still boot
1708 but with the feature disabled. On such a system, this option should
1711 config ARM64_PTR_AUTH_KERNEL
1712 bool "Use pointer authentication for kernel"
1714 depends on ARM64_PTR_AUTH
1715 depends on (CC_HAS_SIGN_RETURN_ADDRESS || CC_HAS_BRANCH_PROT_PAC_RET) && AS_HAS_PAC
1716 # Modern compilers insert a .note.gnu.property section note for PAC
1717 # which is only understood by binutils starting with version 2.33.1.
1718 depends on LD_IS_LLD || LD_VERSION >= 23301 || (CC_IS_GCC && GCC_VERSION < 90100)
1719 depends on !CC_IS_CLANG || AS_HAS_CFI_NEGATE_RA_STATE
1720 depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_REGS)
1722 If the compiler supports the -mbranch-protection or
1723 -msign-return-address flag (e.g. GCC 7 or later), then this option
1724 will cause the kernel itself to be compiled with return address
1725 protection. In this case, and if the target hardware is known to
1726 support pointer authentication, then CONFIG_STACKPROTECTOR can be
1727 disabled with minimal loss of protection.
1729 This feature works with FUNCTION_GRAPH_TRACER option only if
1730 DYNAMIC_FTRACE_WITH_REGS is enabled.
1732 config CC_HAS_BRANCH_PROT_PAC_RET
1733 # GCC 9 or later, clang 8 or later
1734 def_bool $(cc-option,-mbranch-protection=pac-ret+leaf)
1736 config CC_HAS_SIGN_RETURN_ADDRESS
1738 def_bool $(cc-option,-msign-return-address=all)
1741 def_bool $(cc-option,-Wa$(comma)-march=armv8.3-a)
1743 config AS_HAS_CFI_NEGATE_RA_STATE
1744 def_bool $(as-instr,.cfi_startproc\n.cfi_negate_ra_state\n.cfi_endproc\n)
1748 menu "ARMv8.4 architectural features"
1750 config ARM64_AMU_EXTN
1751 bool "Enable support for the Activity Monitors Unit CPU extension"
1754 The activity monitors extension is an optional extension introduced
1755 by the ARMv8.4 CPU architecture. This enables support for version 1
1756 of the activity monitors architecture, AMUv1.
1758 To enable the use of this extension on CPUs that implement it, say Y.
1760 Note that for architectural reasons, firmware _must_ implement AMU
1761 support when running on CPUs that present the activity monitors
1762 extension. The required support is present in:
1763 * Version 1.5 and later of the ARM Trusted Firmware
1765 For kernels that have this configuration enabled but boot with broken
1766 firmware, you may need to say N here until the firmware is fixed.
1767 Otherwise you may experience firmware panics or lockups when
1768 accessing the counter registers. Even if you are not observing these
1769 symptoms, the values returned by the register reads might not
1770 correctly reflect reality. Most commonly, the value read will be 0,
1771 indicating that the counter is not enabled.
1773 config AS_HAS_ARMV8_4
1774 def_bool $(cc-option,-Wa$(comma)-march=armv8.4-a)
1776 config ARM64_TLB_RANGE
1777 bool "Enable support for tlbi range feature"
1779 depends on AS_HAS_ARMV8_4
1781 ARMv8.4-TLBI provides TLBI invalidation instruction that apply to a
1782 range of input addresses.
1784 The feature introduces new assembly instructions, and they were
1785 support when binutils >= 2.30.
1789 menu "ARMv8.5 architectural features"
1791 config AS_HAS_ARMV8_5
1792 def_bool $(cc-option,-Wa$(comma)-march=armv8.5-a)
1795 bool "Branch Target Identification support"
1798 Branch Target Identification (part of the ARMv8.5 Extensions)
1799 provides a mechanism to limit the set of locations to which computed
1800 branch instructions such as BR or BLR can jump.
1802 To make use of BTI on CPUs that support it, say Y.
1804 BTI is intended to provide complementary protection to other control
1805 flow integrity protection mechanisms, such as the Pointer
1806 authentication mechanism provided as part of the ARMv8.3 Extensions.
1807 For this reason, it does not make sense to enable this option without
1808 also enabling support for pointer authentication. Thus, when
1809 enabling this option you should also select ARM64_PTR_AUTH=y.
1811 Userspace binaries must also be specifically compiled to make use of
1812 this mechanism. If you say N here or the hardware does not support
1813 BTI, such binaries can still run, but you get no additional
1814 enforcement of branch destinations.
1816 config ARM64_BTI_KERNEL
1817 bool "Use Branch Target Identification for kernel"
1819 depends on ARM64_BTI
1820 depends on ARM64_PTR_AUTH_KERNEL
1821 depends on CC_HAS_BRANCH_PROT_PAC_RET_BTI
1822 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94697
1823 depends on !CC_IS_GCC || GCC_VERSION >= 100100
1824 # https://github.com/llvm/llvm-project/commit/a88c722e687e6780dcd6a58718350dc76fcc4cc9
1825 depends on !CC_IS_CLANG || CLANG_VERSION >= 120000
1826 depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_REGS)
1828 Build the kernel with Branch Target Identification annotations
1829 and enable enforcement of this for kernel code. When this option
1830 is enabled and the system supports BTI all kernel code including
1831 modular code must have BTI enabled.
1833 config CC_HAS_BRANCH_PROT_PAC_RET_BTI
1834 # GCC 9 or later, clang 8 or later
1835 def_bool $(cc-option,-mbranch-protection=pac-ret+leaf+bti)
1838 bool "Enable support for E0PD"
1841 E0PD (part of the ARMv8.5 extensions) allows us to ensure
1842 that EL0 accesses made via TTBR1 always fault in constant time,
1843 providing similar benefits to KASLR as those provided by KPTI, but
1844 with lower overhead and without disrupting legitimate access to
1845 kernel memory such as SPE.
1847 This option enables E0PD for TTBR1 where available.
1850 bool "Enable support for random number generation"
1853 Random number generation (part of the ARMv8.5 Extensions)
1854 provides a high bandwidth, cryptographically secure
1855 hardware random number generator.
1857 config ARM64_AS_HAS_MTE
1858 # Initial support for MTE went in binutils 2.32.0, checked with
1859 # ".arch armv8.5-a+memtag" below. However, this was incomplete
1860 # as a late addition to the final architecture spec (LDGM/STGM)
1861 # is only supported in the newer 2.32.x and 2.33 binutils
1862 # versions, hence the extra "stgm" instruction check below.
1863 def_bool $(as-instr,.arch armv8.5-a+memtag\nstgm xzr$(comma)[x0])
1866 bool "Memory Tagging Extension support"
1868 depends on ARM64_AS_HAS_MTE && ARM64_TAGGED_ADDR_ABI
1869 depends on AS_HAS_ARMV8_5
1870 depends on AS_HAS_LSE_ATOMICS
1871 # Required for tag checking in the uaccess routines
1872 depends on ARM64_PAN
1873 select ARCH_USES_HIGH_VMA_FLAGS
1875 Memory Tagging (part of the ARMv8.5 Extensions) provides
1876 architectural support for run-time, always-on detection of
1877 various classes of memory error to aid with software debugging
1878 to eliminate vulnerabilities arising from memory-unsafe
1881 This option enables the support for the Memory Tagging
1882 Extension at EL0 (i.e. for userspace).
1884 Selecting this option allows the feature to be detected at
1885 runtime. Any secondary CPU not implementing this feature will
1886 not be allowed a late bring-up.
1888 Userspace binaries that want to use this feature must
1889 explicitly opt in. The mechanism for the userspace is
1892 Documentation/arm64/memory-tagging-extension.rst.
1896 menu "ARMv8.7 architectural features"
1899 bool "Enable support for Enhanced Privileged Access Never (EPAN)"
1901 depends on ARM64_PAN
1903 Enhanced Privileged Access Never (EPAN) allows Privileged
1904 Access Never to be used with Execute-only mappings.
1906 The feature is detected at runtime, and will remain disabled
1907 if the cpu does not implement the feature.
1911 bool "ARM Scalable Vector Extension support"
1914 The Scalable Vector Extension (SVE) is an extension to the AArch64
1915 execution state which complements and extends the SIMD functionality
1916 of the base architecture to support much larger vectors and to enable
1917 additional vectorisation opportunities.
1919 To enable use of this extension on CPUs that implement it, say Y.
1921 On CPUs that support the SVE2 extensions, this option will enable
1924 Note that for architectural reasons, firmware _must_ implement SVE
1925 support when running on SVE capable hardware. The required support
1928 * version 1.5 and later of the ARM Trusted Firmware
1929 * the AArch64 boot wrapper since commit 5e1261e08abf
1930 ("bootwrapper: SVE: Enable SVE for EL2 and below").
1932 For other firmware implementations, consult the firmware documentation
1935 If you need the kernel to boot on SVE-capable hardware with broken
1936 firmware, you may need to say N here until you get your firmware
1937 fixed. Otherwise, you may experience firmware panics or lockups when
1938 booting the kernel. If unsure and you are not observing these
1939 symptoms, you should assume that it is safe to say Y.
1941 config ARM64_MODULE_PLTS
1942 bool "Use PLTs to allow module memory to spill over into vmalloc area"
1944 select HAVE_MOD_ARCH_SPECIFIC
1946 Allocate PLTs when loading modules so that jumps and calls whose
1947 targets are too far away for their relative offsets to be encoded
1948 in the instructions themselves can be bounced via veneers in the
1949 module's PLT. This allows modules to be allocated in the generic
1950 vmalloc area after the dedicated module memory area has been
1953 When running with address space randomization (KASLR), the module
1954 region itself may be too far away for ordinary relative jumps and
1955 calls, and so in that case, module PLTs are required and cannot be
1958 Specific errata workaround(s) might also force module PLTs to be
1959 enabled (ARM64_ERRATUM_843419).
1961 config ARM64_PSEUDO_NMI
1962 bool "Support for NMI-like interrupts"
1965 Adds support for mimicking Non-Maskable Interrupts through the use of
1966 GIC interrupt priority. This support requires version 3 or later of
1969 This high priority configuration for interrupts needs to be
1970 explicitly enabled by setting the kernel parameter
1971 "irqchip.gicv3_pseudo_nmi" to 1.
1976 config ARM64_DEBUG_PRIORITY_MASKING
1977 bool "Debug interrupt priority masking"
1979 This adds runtime checks to functions enabling/disabling
1980 interrupts when using priority masking. The additional checks verify
1981 the validity of ICC_PMR_EL1 when calling concerned functions.
1987 bool "Build a relocatable kernel image" if EXPERT
1988 select ARCH_HAS_RELR
1991 This builds the kernel as a Position Independent Executable (PIE),
1992 which retains all relocation metadata required to relocate the
1993 kernel binary at runtime to a different virtual address than the
1994 address it was linked at.
1995 Since AArch64 uses the RELA relocation format, this requires a
1996 relocation pass at runtime even if the kernel is loaded at the
1997 same address it was linked at.
1999 config RANDOMIZE_BASE
2000 bool "Randomize the address of the kernel image"
2001 select ARM64_MODULE_PLTS if MODULES
2004 Randomizes the virtual address at which the kernel image is
2005 loaded, as a security feature that deters exploit attempts
2006 relying on knowledge of the location of kernel internals.
2008 It is the bootloader's job to provide entropy, by passing a
2009 random u64 value in /chosen/kaslr-seed at kernel entry.
2011 When booting via the UEFI stub, it will invoke the firmware's
2012 EFI_RNG_PROTOCOL implementation (if available) to supply entropy
2013 to the kernel proper. In addition, it will randomise the physical
2014 location of the kernel Image as well.
2018 config RANDOMIZE_MODULE_REGION_FULL
2019 bool "Randomize the module region over a 2 GB range"
2020 depends on RANDOMIZE_BASE
2023 Randomizes the location of the module region inside a 2 GB window
2024 covering the core kernel. This way, it is less likely for modules
2025 to leak information about the location of core kernel data structures
2026 but it does imply that function calls between modules and the core
2027 kernel will need to be resolved via veneers in the module PLT.
2029 When this option is not set, the module region will be randomized over
2030 a limited range that contains the [_stext, _etext] interval of the
2031 core kernel, so branch relocations are almost always in range unless
2032 ARM64_MODULE_PLTS is enabled and the region is exhausted. In this
2033 particular case of region exhaustion, modules might be able to fall
2034 back to a larger 2GB area.
2036 config CC_HAVE_STACKPROTECTOR_SYSREG
2037 def_bool $(cc-option,-mstack-protector-guard=sysreg -mstack-protector-guard-reg=sp_el0 -mstack-protector-guard-offset=0)
2039 config STACKPROTECTOR_PER_TASK
2041 depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_SYSREG
2047 config ARM64_ACPI_PARKING_PROTOCOL
2048 bool "Enable support for the ARM64 ACPI parking protocol"
2051 Enable support for the ARM64 ACPI parking protocol. If disabled
2052 the kernel will not allow booting through the ARM64 ACPI parking
2053 protocol even if the corresponding data is present in the ACPI
2057 string "Default kernel command string"
2060 Provide a set of default command-line options at build time by
2061 entering them here. As a minimum, you should specify the the
2062 root device (e.g. root=/dev/nfs).
2065 prompt "Kernel command line type" if CMDLINE != ""
2066 default CMDLINE_FROM_BOOTLOADER
2068 Choose how the kernel will handle the provided default kernel
2069 command line string.
2071 config CMDLINE_FROM_BOOTLOADER
2072 bool "Use bootloader kernel arguments if available"
2074 Uses the command-line options passed by the boot loader. If
2075 the boot loader doesn't provide any, the default kernel command
2076 string provided in CMDLINE will be used.
2078 config CMDLINE_FORCE
2079 bool "Always use the default kernel command string"
2081 Always use the default kernel command string, even if the boot
2082 loader passes other arguments to the kernel.
2083 This is useful if you cannot or don't want to change the
2084 command-line options your boot loader passes to the kernel.
2092 bool "UEFI runtime support"
2093 depends on OF && !CPU_BIG_ENDIAN
2094 depends on KERNEL_MODE_NEON
2095 select ARCH_SUPPORTS_ACPI
2098 select EFI_PARAMS_FROM_FDT
2099 select EFI_RUNTIME_WRAPPERS
2101 select EFI_GENERIC_STUB
2102 imply IMA_SECURE_AND_OR_TRUSTED_BOOT
2105 This option provides support for runtime services provided
2106 by UEFI firmware (such as non-volatile variables, realtime
2107 clock, and platform reset). A UEFI stub is also provided to
2108 allow the kernel to be booted as an EFI application. This
2109 is only useful on systems that have UEFI firmware.
2112 bool "Enable support for SMBIOS (DMI) tables"
2116 This enables SMBIOS/DMI feature for systems.
2118 This option is only useful on systems that have UEFI firmware.
2119 However, even with this option, the resultant kernel should
2120 continue to boot on existing non-UEFI platforms.
2124 config SYSVIPC_COMPAT
2126 depends on COMPAT && SYSVIPC
2128 menu "Power management options"
2130 source "kernel/power/Kconfig"
2132 config ARCH_HIBERNATION_POSSIBLE
2136 config ARCH_HIBERNATION_HEADER
2138 depends on HIBERNATION
2140 config ARCH_SUSPEND_POSSIBLE
2145 menu "CPU Power Management"
2147 source "drivers/cpuidle/Kconfig"
2149 source "drivers/cpufreq/Kconfig"
2153 source "drivers/acpi/Kconfig"
2155 source "arch/arm64/kvm/Kconfig"
2158 source "arch/arm64/crypto/Kconfig"