1# SPDX-License-Identifier: GPL-2.0-only 2config ARM64 3 def_bool y 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 22 select ARCH_HAS_KCOV 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 77 select ARM_AMBA 78 select ARM_ARCH_TIMER 79 select ARM_GIC 80 select AUDIT_ARCH_COMPAT_GENERIC 81 select ARM_GIC_V2M if PCI 82 select ARM_GIC_V3 83 select ARM_GIC_V3_ITS if PCI 84 select ARM_PSCI_FW 85 select BUILDTIME_EXTABLE_SORT 86 select CLONE_BACKWARDS 87 select COMMON_CLK 88 select CPU_PM if (SUSPEND || CPU_IDLE) 89 select CRC32 90 select DCACHE_WORD_ACCESS 91 select DMA_DIRECT_REMAP 92 select EDAC_SUPPORT 93 select FRAME_POINTER 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 115 select HAVE_PCI 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 137 select HAVE_EBPF_JIT 138 select HAVE_C_RECORDMCOUNT 139 select HAVE_CMPXCHG_DOUBLE 140 select HAVE_CMPXCHG_LOCAL 141 select HAVE_CONTEXT_TRACKING 142 select HAVE_DEBUG_BUGVERBOSE 143 select HAVE_DEBUG_KMEMLEAK 144 select HAVE_DMA_CONTIGUOUS 145 select HAVE_DYNAMIC_FTRACE 146 select HAVE_EFFICIENT_UNALIGNED_ACCESS 147 select HAVE_FAST_GUP 148 select HAVE_FTRACE_MCOUNT_RECORD 149 select HAVE_FUNCTION_TRACER 150 select HAVE_FUNCTION_ERROR_INJECTION 151 select HAVE_FUNCTION_GRAPH_TRACER 152 select HAVE_GCC_PLUGINS 153 select HAVE_HW_BREAKPOINT if PERF_EVENTS 154 select HAVE_IRQ_TIME_ACCOUNTING 155 select HAVE_MEMBLOCK_NODE_MAP if NUMA 156 select HAVE_NMI 157 select HAVE_PATA_PLATFORM 158 select HAVE_PERF_EVENTS 159 select HAVE_PERF_REGS 160 select HAVE_PERF_USER_STACK_DUMP 161 select HAVE_REGS_AND_STACK_ACCESS_API 162 select HAVE_FUNCTION_ARG_ACCESS_API 163 select HAVE_RCU_TABLE_FREE 164 select HAVE_RSEQ 165 select HAVE_STACKPROTECTOR 166 select HAVE_SYSCALL_TRACEPOINTS 167 select HAVE_KPROBES 168 select HAVE_KRETPROBES 169 select HAVE_GENERIC_VDSO 170 select IOMMU_DMA if IOMMU_SUPPORT 171 select IRQ_DOMAIN 172 select IRQ_FORCED_THREADING 173 select MODULES_USE_ELF_RELA 174 select NEED_DMA_MAP_STATE 175 select NEED_SG_DMA_LENGTH 176 select OF 177 select OF_EARLY_FLATTREE 178 select PCI_DOMAINS_GENERIC if PCI 179 select PCI_ECAM if (ACPI && PCI) 180 select PCI_SYSCALL if PCI 181 select POWER_RESET 182 select POWER_SUPPLY 183 select REFCOUNT_FULL 184 select SPARSE_IRQ 185 select SWIOTLB 186 select SYSCTL_EXCEPTION_TRACE 187 select THREAD_INFO_IN_TASK 188 help 189 ARM 64-bit (AArch64) Linux support. 190 191config 64BIT 192 def_bool y 193 194config MMU 195 def_bool y 196 197config ARM64_PAGE_SHIFT 198 int 199 default 16 if ARM64_64K_PAGES 200 default 14 if ARM64_16K_PAGES 201 default 12 202 203config ARM64_CONT_SHIFT 204 int 205 default 5 if ARM64_64K_PAGES 206 default 7 if ARM64_16K_PAGES 207 default 4 208 209config ARCH_MMAP_RND_BITS_MIN 210 default 14 if ARM64_64K_PAGES 211 default 16 if ARM64_16K_PAGES 212 default 18 213 214# max bits determined by the following formula: 215# VA_BITS - PAGE_SHIFT - 3 216config 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 226 default 18 227 228config ARCH_MMAP_RND_COMPAT_BITS_MIN 229 default 7 if ARM64_64K_PAGES 230 default 9 if ARM64_16K_PAGES 231 default 11 232 233config ARCH_MMAP_RND_COMPAT_BITS_MAX 234 default 16 235 236config NO_IOPORT_MAP 237 def_bool y if !PCI 238 239config STACKTRACE_SUPPORT 240 def_bool y 241 242config ILLEGAL_POINTER_VALUE 243 hex 244 default 0xdead000000000000 245 246config LOCKDEP_SUPPORT 247 def_bool y 248 249config TRACE_IRQFLAGS_SUPPORT 250 def_bool y 251 252config GENERIC_BUG 253 def_bool y 254 depends on BUG 255 256config GENERIC_BUG_RELATIVE_POINTERS 257 def_bool y 258 depends on GENERIC_BUG 259 260config GENERIC_HWEIGHT 261 def_bool y 262 263config GENERIC_CSUM 264 def_bool y 265 266config GENERIC_CALIBRATE_DELAY 267 def_bool y 268 269config ZONE_DMA32 270 bool "Support DMA32 zone" if EXPERT 271 default y 272 273config ARCH_ENABLE_MEMORY_HOTPLUG 274 def_bool y 275 276config SMP 277 def_bool y 278 279config KERNEL_MODE_NEON 280 def_bool y 281 282config FIX_EARLYCON_MEM 283 def_bool y 284 285config PGTABLE_LEVELS 286 int 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_48 293 294config ARCH_SUPPORTS_UPROBES 295 def_bool y 296 297config ARCH_PROC_KCORE_TEXT 298 def_bool y 299 300config KASAN_SHADOW_OFFSET 301 hex 302 depends on KASAN 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 314 315source "arch/arm64/Kconfig.platforms" 316 317menu "Kernel Features" 318 319menu "ARM errata workarounds via the alternatives framework" 320 321config ARM64_WORKAROUND_CLEAN_CACHE 322 bool 323 324config ARM64_ERRATUM_826319 325 bool "Cortex-A53: 826319: System might deadlock if a write cannot complete until read data is accepted" 326 default y 327 select ARM64_WORKAROUND_CLEAN_CACHE 328 help 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. 332 333 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 336 system can deadlock. 337 338 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. 343 344 If unsure, say Y. 345 346config ARM64_ERRATUM_827319 347 bool "Cortex-A53: 827319: Data cache clean instructions might cause overlapping transactions to the interconnect" 348 default y 349 select ARM64_WORKAROUND_CLEAN_CACHE 350 help 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. 354 355 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. 359 360 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. 365 366 If unsure, say Y. 367 368config ARM64_ERRATUM_824069 369 bool "Cortex-A53: 824069: Cache line might not be marked as clean after a CleanShared snoop" 370 default y 371 select ARM64_WORKAROUND_CLEAN_CACHE 372 help 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. 376 377 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. 382 383 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. 388 389 If unsure, say Y. 390 391config ARM64_ERRATUM_819472 392 bool "Cortex-A53: 819472: Store exclusive instructions might cause data corruption" 393 default y 394 select ARM64_WORKAROUND_CLEAN_CACHE 395 help 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. 399 400 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. 404 405 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. 410 411 If unsure, say Y. 412 413config ARM64_ERRATUM_832075 414 bool "Cortex-A57: 832075: possible deadlock on mixing exclusive memory accesses with device loads" 415 default y 416 help 417 This option adds an alternative code sequence to work around ARM 418 erratum 832075 on Cortex-A57 parts up to r1p2. 419 420 Affected Cortex-A57 parts might deadlock when exclusive load/store 421 instructions to Write-Back memory are mixed with Device loads. 422 423 The workaround is to promote device loads to use Load-Acquire 424 semantics. 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. 428 429 If unsure, say Y. 430 431config ARM64_ERRATUM_834220 432 bool "Cortex-A57: 834220: Stage 2 translation fault might be incorrectly reported in presence of a Stage 1 fault" 433 depends on KVM 434 default y 435 help 436 This option adds an alternative code sequence to work around ARM 437 erratum 834220 on Cortex-A57 parts up to r1p2. 438 439 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. 443 444 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. 449 450 If unsure, say Y. 451 452config ARM64_ERRATUM_845719 453 bool "Cortex-A53: 845719: a load might read incorrect data" 454 depends on COMPAT 455 default y 456 help 457 This option adds an alternative code sequence to work around ARM 458 erratum 845719 on Cortex-A53 parts up to r0p4. 459 460 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. 464 465 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. 470 471 If unsure, say Y. 472 473config ARM64_ERRATUM_843419 474 bool "Cortex-A53: 843419: A load or store might access an incorrect address" 475 default y 476 select ARM64_MODULE_PLTS if MODULES 477 help 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. 482 483 If unsure, say Y. 484 485config ARM64_ERRATUM_1024718 486 bool "Cortex-A55: 1024718: Update of DBM/AP bits without break before make might result in incorrect update" 487 default y 488 help 489 This option adds a workaround for ARM Cortex-A55 Erratum 1024718. 490 491 Affected Cortex-A55 cores (r0p0, r0p1, r1p0) 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. 496 497 If unsure, say Y. 498 499config ARM64_ERRATUM_1418040 500 bool "Cortex-A76/Neoverse-N1: MRC read following MRRC read of specific Generic Timer in AArch32 might give incorrect result" 501 default y 502 depends on COMPAT 503 help 504 This option adds a workaround for ARM Cortex-A76/Neoverse-N1 505 errata 1188873 and 1418040. 506 507 Affected Cortex-A76/Neoverse-N1 cores (r0p0 to r3p1) could 508 cause register corruption when accessing the timer registers 509 from AArch32 userspace. 510 511 If unsure, say Y. 512 513config 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" 515 default y 516 help 517 This option adds a workaround for ARM Cortex-A76 erratum 1165522. 518 519 Affected Cortex-A76 cores (r0p0, r1p0, r2p0) could end-up with 520 corrupted TLBs by speculating an AT instruction during a guest 521 context switch. 522 523 If unsure, say Y. 524 525config ARM64_ERRATUM_1286807 526 bool "Cortex-A76: Modification of the translation table for a virtual address might lead to read-after-read ordering violation" 527 default y 528 select ARM64_WORKAROUND_REPEAT_TLBI 529 help 530 This option adds a workaround for ARM Cortex-A76 erratum 1286807. 531 532 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. 540 541 If unsure, say Y. 542 543config ARM64_ERRATUM_1463225 544 bool "Cortex-A76: Software Step might prevent interrupt recognition" 545 default y 546 help 547 This option adds a workaround for Arm Cortex-A76 erratum 1463225. 548 549 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. 554 555 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. 558 559 If unsure, say Y. 560 561config CAVIUM_ERRATUM_22375 562 bool "Cavium erratum 22375, 24313" 563 default y 564 help 565 Enable workaround for errata 22375 and 24313. 566 567 This implements two gicv3-its errata workarounds for ThunderX. Both 568 with a small impact affecting only ITS table allocation. 569 570 erratum 22375: only alloc 8MB table size 571 erratum 24313: ignore memory access type 572 573 The fixes are in ITS initialization and basically ignore memory access 574 type and table size provided by the TYPER and BASER registers. 575 576 If unsure, say Y. 577 578config CAVIUM_ERRATUM_23144 579 bool "Cavium erratum 23144: ITS SYNC hang on dual socket system" 580 depends on NUMA 581 default y 582 help 583 ITS SYNC command hang for cross node io and collections/cpu mapping. 584 585 If unsure, say Y. 586 587config CAVIUM_ERRATUM_23154 588 bool "Cavium erratum 23154: Access to ICC_IAR1_EL1 is not sync'ed" 589 default y 590 help 591 The gicv3 of ThunderX requires a modified version for 592 reading the IAR status to ensure data synchronization 593 (access to icc_iar1_el1 is not sync'ed before and after). 594 595 If unsure, say Y. 596 597config CAVIUM_ERRATUM_27456 598 bool "Cavium erratum 27456: Broadcast TLBI instructions may cause icache corruption" 599 default y 600 help 601 On ThunderX T88 pass 1.x through 2.1 parts, broadcast TLBI 602 instructions may cause the icache to become corrupted if it 603 contains data for a non-current ASID. The fix is to 604 invalidate the icache when changing the mm context. 605 606 If unsure, say Y. 607 608config CAVIUM_ERRATUM_30115 609 bool "Cavium erratum 30115: Guest may disable interrupts in host" 610 default y 611 help 612 On ThunderX T88 pass 1.x through 2.2, T81 pass 1.0 through 613 1.2, and T83 Pass 1.0, KVM guest execution may disable 614 interrupts in host. Trapping both GICv3 group-0 and group-1 615 accesses sidesteps the issue. 616 617 If unsure, say Y. 618 619config QCOM_FALKOR_ERRATUM_1003 620 bool "Falkor E1003: Incorrect translation due to ASID change" 621 default y 622 help 623 On Falkor v1, an incorrect ASID may be cached in the TLB when ASID 624 and BADDR are changed together in TTBRx_EL1. Since we keep the ASID 625 in TTBR1_EL1, this situation only occurs in the entry trampoline and 626 then only for entries in the walk cache, since the leaf translation 627 is unchanged. Work around the erratum by invalidating the walk cache 628 entries for the trampoline before entering the kernel proper. 629 630config ARM64_WORKAROUND_REPEAT_TLBI 631 bool 632 633config QCOM_FALKOR_ERRATUM_1009 634 bool "Falkor E1009: Prematurely complete a DSB after a TLBI" 635 default y 636 select ARM64_WORKAROUND_REPEAT_TLBI 637 help 638 On Falkor v1, the CPU may prematurely complete a DSB following a 639 TLBI xxIS invalidate maintenance operation. Repeat the TLBI operation 640 one more time to fix the issue. 641 642 If unsure, say Y. 643 644config QCOM_QDF2400_ERRATUM_0065 645 bool "QDF2400 E0065: Incorrect GITS_TYPER.ITT_Entry_size" 646 default y 647 help 648 On Qualcomm Datacenter Technologies QDF2400 SoC, ITS hardware reports 649 ITE size incorrectly. The GITS_TYPER.ITT_Entry_size field should have 650 been indicated as 16Bytes (0xf), not 8Bytes (0x7). 651 652 If unsure, say Y. 653 654config SOCIONEXT_SYNQUACER_PREITS 655 bool "Socionext Synquacer: Workaround for GICv3 pre-ITS" 656 default y 657 help 658 Socionext Synquacer SoCs implement a separate h/w block to generate 659 MSI doorbell writes with non-zero values for the device ID. 660 661 If unsure, say Y. 662 663config HISILICON_ERRATUM_161600802 664 bool "Hip07 161600802: Erroneous redistributor VLPI base" 665 default y 666 help 667 The HiSilicon Hip07 SoC uses the wrong redistributor base 668 when issued ITS commands such as VMOVP and VMAPP, and requires 669 a 128kB offset to be applied to the target address in this commands. 670 671 If unsure, say Y. 672 673config QCOM_FALKOR_ERRATUM_E1041 674 bool "Falkor E1041: Speculative instruction fetches might cause errant memory access" 675 default y 676 help 677 Falkor CPU may speculatively fetch instructions from an improper 678 memory location when MMU translation is changed from SCTLR_ELn[M]=1 679 to SCTLR_ELn[M]=0. Prefix an ISB instruction to fix the problem. 680 681 If unsure, say Y. 682 683config FUJITSU_ERRATUM_010001 684 bool "Fujitsu-A64FX erratum E#010001: Undefined fault may occur wrongly" 685 default y 686 help 687 This option adds a workaround for Fujitsu-A64FX erratum E#010001. 688 On some variants of the Fujitsu-A64FX cores ver(1.0, 1.1), memory 689 accesses may cause undefined fault (Data abort, DFSC=0b111111). 690 This fault occurs under a specific hardware condition when a 691 load/store instruction performs an address translation using: 692 case-1 TTBR0_EL1 with TCR_EL1.NFD0 == 1. 693 case-2 TTBR0_EL2 with TCR_EL2.NFD0 == 1. 694 case-3 TTBR1_EL1 with TCR_EL1.NFD1 == 1. 695 case-4 TTBR1_EL2 with TCR_EL2.NFD1 == 1. 696 697 The workaround is to ensure these bits are clear in TCR_ELx. 698 The workaround only affects the Fujitsu-A64FX. 699 700 If unsure, say Y. 701 702endmenu 703 704 705choice 706 prompt "Page size" 707 default ARM64_4K_PAGES 708 help 709 Page size (translation granule) configuration. 710 711config ARM64_4K_PAGES 712 bool "4KB" 713 help 714 This feature enables 4KB pages support. 715 716config ARM64_16K_PAGES 717 bool "16KB" 718 help 719 The system will use 16KB pages support. AArch32 emulation 720 requires applications compiled with 16K (or a multiple of 16K) 721 aligned segments. 722 723config ARM64_64K_PAGES 724 bool "64KB" 725 help 726 This feature enables 64KB pages support (4KB by default) 727 allowing only two levels of page tables and faster TLB 728 look-up. AArch32 emulation requires applications compiled 729 with 64K aligned segments. 730 731endchoice 732 733choice 734 prompt "Virtual address space size" 735 default ARM64_VA_BITS_39 if ARM64_4K_PAGES 736 default ARM64_VA_BITS_47 if ARM64_16K_PAGES 737 default ARM64_VA_BITS_42 if ARM64_64K_PAGES 738 help 739 Allows choosing one of multiple possible virtual address 740 space sizes. The level of translation table is determined by 741 a combination of page size and virtual address space size. 742 743config ARM64_VA_BITS_36 744 bool "36-bit" if EXPERT 745 depends on ARM64_16K_PAGES 746 747config ARM64_VA_BITS_39 748 bool "39-bit" 749 depends on ARM64_4K_PAGES 750 751config ARM64_VA_BITS_42 752 bool "42-bit" 753 depends on ARM64_64K_PAGES 754 755config ARM64_VA_BITS_47 756 bool "47-bit" 757 depends on ARM64_16K_PAGES 758 759config ARM64_VA_BITS_48 760 bool "48-bit" 761 762config ARM64_VA_BITS_52 763 bool "52-bit" 764 depends on ARM64_64K_PAGES && (ARM64_PAN || !ARM64_SW_TTBR0_PAN) 765 help 766 Enable 52-bit virtual addressing for userspace when explicitly 767 requested via a hint to mmap(). The kernel will also use 52-bit 768 virtual addresses for its own mappings (provided HW support for 769 this feature is available, otherwise it reverts to 48-bit). 770 771 NOTE: Enabling 52-bit virtual addressing in conjunction with 772 ARMv8.3 Pointer Authentication will result in the PAC being 773 reduced from 7 bits to 3 bits, which may have a significant 774 impact on its susceptibility to brute-force attacks. 775 776 If unsure, select 48-bit virtual addressing instead. 777 778endchoice 779 780config ARM64_FORCE_52BIT 781 bool "Force 52-bit virtual addresses for userspace" 782 depends on ARM64_VA_BITS_52 && EXPERT 783 help 784 For systems with 52-bit userspace VAs enabled, the kernel will attempt 785 to maintain compatibility with older software by providing 48-bit VAs 786 unless a hint is supplied to mmap. 787 788 This configuration option disables the 48-bit compatibility logic, and 789 forces all userspace addresses to be 52-bit on HW that supports it. One 790 should only enable this configuration option for stress testing userspace 791 memory management code. If unsure say N here. 792 793config ARM64_VA_BITS 794 int 795 default 36 if ARM64_VA_BITS_36 796 default 39 if ARM64_VA_BITS_39 797 default 42 if ARM64_VA_BITS_42 798 default 47 if ARM64_VA_BITS_47 799 default 48 if ARM64_VA_BITS_48 800 default 52 if ARM64_VA_BITS_52 801 802choice 803 prompt "Physical address space size" 804 default ARM64_PA_BITS_48 805 help 806 Choose the maximum physical address range that the kernel will 807 support. 808 809config ARM64_PA_BITS_48 810 bool "48-bit" 811 812config ARM64_PA_BITS_52 813 bool "52-bit (ARMv8.2)" 814 depends on ARM64_64K_PAGES 815 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN 816 help 817 Enable support for a 52-bit physical address space, introduced as 818 part of the ARMv8.2-LPA extension. 819 820 With this enabled, the kernel will also continue to work on CPUs that 821 do not support ARMv8.2-LPA, but with some added memory overhead (and 822 minor performance overhead). 823 824endchoice 825 826config ARM64_PA_BITS 827 int 828 default 48 if ARM64_PA_BITS_48 829 default 52 if ARM64_PA_BITS_52 830 831config CPU_BIG_ENDIAN 832 bool "Build big-endian kernel" 833 help 834 Say Y if you plan on running a kernel in big-endian mode. 835 836config SCHED_MC 837 bool "Multi-core scheduler support" 838 help 839 Multi-core scheduler support improves the CPU scheduler's decision 840 making when dealing with multi-core CPU chips at a cost of slightly 841 increased overhead in some places. If unsure say N here. 842 843config SCHED_SMT 844 bool "SMT scheduler support" 845 help 846 Improves the CPU scheduler's decision making when dealing with 847 MultiThreading at a cost of slightly increased overhead in some 848 places. If unsure say N here. 849 850config NR_CPUS 851 int "Maximum number of CPUs (2-4096)" 852 range 2 4096 853 default "256" 854 855config HOTPLUG_CPU 856 bool "Support for hot-pluggable CPUs" 857 select GENERIC_IRQ_MIGRATION 858 help 859 Say Y here to experiment with turning CPUs off and on. CPUs 860 can be controlled through /sys/devices/system/cpu. 861 862# Common NUMA Features 863config NUMA 864 bool "Numa Memory Allocation and Scheduler Support" 865 select ACPI_NUMA if ACPI 866 select OF_NUMA 867 help 868 Enable NUMA (Non Uniform Memory Access) support. 869 870 The kernel will try to allocate memory used by a CPU on the 871 local memory of the CPU and add some more 872 NUMA awareness to the kernel. 873 874config NODES_SHIFT 875 int "Maximum NUMA Nodes (as a power of 2)" 876 range 1 10 877 default "2" 878 depends on NEED_MULTIPLE_NODES 879 help 880 Specify the maximum number of NUMA Nodes available on the target 881 system. Increases memory reserved to accommodate various tables. 882 883config USE_PERCPU_NUMA_NODE_ID 884 def_bool y 885 depends on NUMA 886 887config HAVE_SETUP_PER_CPU_AREA 888 def_bool y 889 depends on NUMA 890 891config NEED_PER_CPU_EMBED_FIRST_CHUNK 892 def_bool y 893 depends on NUMA 894 895config HOLES_IN_ZONE 896 def_bool y 897 898source "kernel/Kconfig.hz" 899 900config ARCH_SUPPORTS_DEBUG_PAGEALLOC 901 def_bool y 902 903config ARCH_SPARSEMEM_ENABLE 904 def_bool y 905 select SPARSEMEM_VMEMMAP_ENABLE 906 907config ARCH_SPARSEMEM_DEFAULT 908 def_bool ARCH_SPARSEMEM_ENABLE 909 910config ARCH_SELECT_MEMORY_MODEL 911 def_bool ARCH_SPARSEMEM_ENABLE 912 913config ARCH_FLATMEM_ENABLE 914 def_bool !NUMA 915 916config HAVE_ARCH_PFN_VALID 917 def_bool y 918 919config HW_PERF_EVENTS 920 def_bool y 921 depends on ARM_PMU 922 923config SYS_SUPPORTS_HUGETLBFS 924 def_bool y 925 926config ARCH_WANT_HUGE_PMD_SHARE 927 928config ARCH_HAS_CACHE_LINE_SIZE 929 def_bool y 930 931config ARCH_ENABLE_SPLIT_PMD_PTLOCK 932 def_bool y if PGTABLE_LEVELS > 2 933 934config SECCOMP 935 bool "Enable seccomp to safely compute untrusted bytecode" 936 ---help--- 937 This kernel feature is useful for number crunching applications 938 that may need to compute untrusted bytecode during their 939 execution. By using pipes or other transports made available to 940 the process as file descriptors supporting the read/write 941 syscalls, it's possible to isolate those applications in 942 their own address space using seccomp. Once seccomp is 943 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 944 and the task is only allowed to execute a few safe syscalls 945 defined by each seccomp mode. 946 947config PARAVIRT 948 bool "Enable paravirtualization code" 949 help 950 This changes the kernel so it can modify itself when it is run 951 under a hypervisor, potentially improving performance significantly 952 over full virtualization. 953 954config PARAVIRT_TIME_ACCOUNTING 955 bool "Paravirtual steal time accounting" 956 select PARAVIRT 957 help 958 Select this option to enable fine granularity task steal time 959 accounting. Time spent executing other tasks in parallel with 960 the current vCPU is discounted from the vCPU power. To account for 961 that, there can be a small performance impact. 962 963 If in doubt, say N here. 964 965config KEXEC 966 depends on PM_SLEEP_SMP 967 select KEXEC_CORE 968 bool "kexec system call" 969 ---help--- 970 kexec is a system call that implements the ability to shutdown your 971 current kernel, and to start another kernel. It is like a reboot 972 but it is independent of the system firmware. And like a reboot 973 you can start any kernel with it, not just Linux. 974 975config KEXEC_FILE 976 bool "kexec file based system call" 977 select KEXEC_CORE 978 help 979 This is new version of kexec system call. This system call is 980 file based and takes file descriptors as system call argument 981 for kernel and initramfs as opposed to list of segments as 982 accepted by previous system call. 983 984config KEXEC_SIG 985 bool "Verify kernel signature during kexec_file_load() syscall" 986 depends on KEXEC_FILE 987 help 988 Select this option to verify a signature with loaded kernel 989 image. If configured, any attempt of loading a image without 990 valid signature will fail. 991 992 In addition to that option, you need to enable signature 993 verification for the corresponding kernel image type being 994 loaded in order for this to work. 995 996config KEXEC_IMAGE_VERIFY_SIG 997 bool "Enable Image signature verification support" 998 default y 999 depends on KEXEC_SIG 1000 depends on EFI && SIGNED_PE_FILE_VERIFICATION 1001 help 1002 Enable Image signature verification support. 1003 1004comment "Support for PE file signature verification disabled" 1005 depends on KEXEC_SIG 1006 depends on !EFI || !SIGNED_PE_FILE_VERIFICATION 1007 1008config CRASH_DUMP 1009 bool "Build kdump crash kernel" 1010 help 1011 Generate crash dump after being started by kexec. This should 1012 be normally only set in special crash dump kernels which are 1013 loaded in the main kernel with kexec-tools into a specially 1014 reserved region and then later executed after a crash by 1015 kdump/kexec. 1016 1017 For more details see Documentation/admin-guide/kdump/kdump.rst 1018 1019config XEN_DOM0 1020 def_bool y 1021 depends on XEN 1022 1023config XEN 1024 bool "Xen guest support on ARM64" 1025 depends on ARM64 && OF 1026 select SWIOTLB_XEN 1027 select PARAVIRT 1028 help 1029 Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64. 1030 1031config FORCE_MAX_ZONEORDER 1032 int 1033 default "14" if (ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE) 1034 default "12" if (ARM64_16K_PAGES && TRANSPARENT_HUGEPAGE) 1035 default "11" 1036 help 1037 The kernel memory allocator divides physically contiguous memory 1038 blocks into "zones", where each zone is a power of two number of 1039 pages. This option selects the largest power of two that the kernel 1040 keeps in the memory allocator. If you need to allocate very large 1041 blocks of physically contiguous memory, then you may need to 1042 increase this value. 1043 1044 This config option is actually maximum order plus one. For example, 1045 a value of 11 means that the largest free memory block is 2^10 pages. 1046 1047 We make sure that we can allocate upto a HugePage size for each configuration. 1048 Hence we have : 1049 MAX_ORDER = (PMD_SHIFT - PAGE_SHIFT) + 1 => PAGE_SHIFT - 2 1050 1051 However for 4K, we choose a higher default value, 11 as opposed to 10, giving us 1052 4M allocations matching the default size used by generic code. 1053 1054config UNMAP_KERNEL_AT_EL0 1055 bool "Unmap kernel when running in userspace (aka \"KAISER\")" if EXPERT 1056 default y 1057 help 1058 Speculation attacks against some high-performance processors can 1059 be used to bypass MMU permission checks and leak kernel data to 1060 userspace. This can be defended against by unmapping the kernel 1061 when running in userspace, mapping it back in on exception entry 1062 via a trampoline page in the vector table. 1063 1064 If unsure, say Y. 1065 1066config HARDEN_BRANCH_PREDICTOR 1067 bool "Harden the branch predictor against aliasing attacks" if EXPERT 1068 default y 1069 help 1070 Speculation attacks against some high-performance processors rely on 1071 being able to manipulate the branch predictor for a victim context by 1072 executing aliasing branches in the attacker context. Such attacks 1073 can be partially mitigated against by clearing internal branch 1074 predictor state and limiting the prediction logic in some situations. 1075 1076 This config option will take CPU-specific actions to harden the 1077 branch predictor against aliasing attacks and may rely on specific 1078 instruction sequences or control bits being set by the system 1079 firmware. 1080 1081 If unsure, say Y. 1082 1083config HARDEN_EL2_VECTORS 1084 bool "Harden EL2 vector mapping against system register leak" if EXPERT 1085 default y 1086 help 1087 Speculation attacks against some high-performance processors can 1088 be used to leak privileged information such as the vector base 1089 register, resulting in a potential defeat of the EL2 layout 1090 randomization. 1091 1092 This config option will map the vectors to a fixed location, 1093 independent of the EL2 code mapping, so that revealing VBAR_EL2 1094 to an attacker does not give away any extra information. This 1095 only gets enabled on affected CPUs. 1096 1097 If unsure, say Y. 1098 1099config ARM64_SSBD 1100 bool "Speculative Store Bypass Disable" if EXPERT 1101 default y 1102 help 1103 This enables mitigation of the bypassing of previous stores 1104 by speculative loads. 1105 1106 If unsure, say Y. 1107 1108config RODATA_FULL_DEFAULT_ENABLED 1109 bool "Apply r/o permissions of VM areas also to their linear aliases" 1110 default y 1111 help 1112 Apply read-only attributes of VM areas to the linear alias of 1113 the backing pages as well. This prevents code or read-only data 1114 from being modified (inadvertently or intentionally) via another 1115 mapping of the same memory page. This additional enhancement can 1116 be turned off at runtime by passing rodata=[off|on] (and turned on 1117 with rodata=full if this option is set to 'n') 1118 1119 This requires the linear region to be mapped down to pages, 1120 which may adversely affect performance in some cases. 1121 1122config ARM64_SW_TTBR0_PAN 1123 bool "Emulate Privileged Access Never using TTBR0_EL1 switching" 1124 help 1125 Enabling this option prevents the kernel from accessing 1126 user-space memory directly by pointing TTBR0_EL1 to a reserved 1127 zeroed area and reserved ASID. The user access routines 1128 restore the valid TTBR0_EL1 temporarily. 1129 1130config ARM64_TAGGED_ADDR_ABI 1131 bool "Enable the tagged user addresses syscall ABI" 1132 default y 1133 help 1134 When this option is enabled, user applications can opt in to a 1135 relaxed ABI via prctl() allowing tagged addresses to be passed 1136 to system calls as pointer arguments. For details, see 1137 Documentation/arm64/tagged-address-abi.rst. 1138 1139menuconfig COMPAT 1140 bool "Kernel support for 32-bit EL0" 1141 depends on ARM64_4K_PAGES || EXPERT 1142 select COMPAT_BINFMT_ELF if BINFMT_ELF 1143 select HAVE_UID16 1144 select OLD_SIGSUSPEND3 1145 select COMPAT_OLD_SIGACTION 1146 help 1147 This option enables support for a 32-bit EL0 running under a 64-bit 1148 kernel at EL1. AArch32-specific components such as system calls, 1149 the user helper functions, VFP support and the ptrace interface are 1150 handled appropriately by the kernel. 1151 1152 If you use a page size other than 4KB (i.e, 16KB or 64KB), please be aware 1153 that you will only be able to execute AArch32 binaries that were compiled 1154 with page size aligned segments. 1155 1156 If you want to execute 32-bit userspace applications, say Y. 1157 1158if COMPAT 1159 1160config KUSER_HELPERS 1161 bool "Enable kuser helpers page for 32-bit applications" 1162 default y 1163 help 1164 Warning: disabling this option may break 32-bit user programs. 1165 1166 Provide kuser helpers to compat tasks. The kernel provides 1167 helper code to userspace in read only form at a fixed location 1168 to allow userspace to be independent of the CPU type fitted to 1169 the system. This permits binaries to be run on ARMv4 through 1170 to ARMv8 without modification. 1171 1172 See Documentation/arm/kernel_user_helpers.rst for details. 1173 1174 However, the fixed address nature of these helpers can be used 1175 by ROP (return orientated programming) authors when creating 1176 exploits. 1177 1178 If all of the binaries and libraries which run on your platform 1179 are built specifically for your platform, and make no use of 1180 these helpers, then you can turn this option off to hinder 1181 such exploits. However, in that case, if a binary or library 1182 relying on those helpers is run, it will not function correctly. 1183 1184 Say N here only if you are absolutely certain that you do not 1185 need these helpers; otherwise, the safe option is to say Y. 1186 1187config COMPAT_VDSO 1188 bool "Enable vDSO for 32-bit applications" 1189 depends on !CPU_BIG_ENDIAN && "$(CROSS_COMPILE_COMPAT)" != "" 1190 select GENERIC_COMPAT_VDSO 1191 default y 1192 help 1193 Place in the process address space of 32-bit applications an 1194 ELF shared object providing fast implementations of gettimeofday 1195 and clock_gettime. 1196 1197 You must have a 32-bit build of glibc 2.22 or later for programs 1198 to seamlessly take advantage of this. 1199 1200menuconfig ARMV8_DEPRECATED 1201 bool "Emulate deprecated/obsolete ARMv8 instructions" 1202 depends on SYSCTL 1203 help 1204 Legacy software support may require certain instructions 1205 that have been deprecated or obsoleted in the architecture. 1206 1207 Enable this config to enable selective emulation of these 1208 features. 1209 1210 If unsure, say Y 1211 1212if ARMV8_DEPRECATED 1213 1214config SWP_EMULATION 1215 bool "Emulate SWP/SWPB instructions" 1216 help 1217 ARMv8 obsoletes the use of A32 SWP/SWPB instructions such that 1218 they are always undefined. Say Y here to enable software 1219 emulation of these instructions for userspace using LDXR/STXR. 1220 1221 In some older versions of glibc [<=2.8] SWP is used during futex 1222 trylock() operations with the assumption that the code will not 1223 be preempted. This invalid assumption may be more likely to fail 1224 with SWP emulation enabled, leading to deadlock of the user 1225 application. 1226 1227 NOTE: when accessing uncached shared regions, LDXR/STXR rely 1228 on an external transaction monitoring block called a global 1229 monitor to maintain update atomicity. If your system does not 1230 implement a global monitor, this option can cause programs that 1231 perform SWP operations to uncached memory to deadlock. 1232 1233 If unsure, say Y 1234 1235config CP15_BARRIER_EMULATION 1236 bool "Emulate CP15 Barrier instructions" 1237 help 1238 The CP15 barrier instructions - CP15ISB, CP15DSB, and 1239 CP15DMB - are deprecated in ARMv8 (and ARMv7). It is 1240 strongly recommended to use the ISB, DSB, and DMB 1241 instructions instead. 1242 1243 Say Y here to enable software emulation of these 1244 instructions for AArch32 userspace code. When this option is 1245 enabled, CP15 barrier usage is traced which can help 1246 identify software that needs updating. 1247 1248 If unsure, say Y 1249 1250config SETEND_EMULATION 1251 bool "Emulate SETEND instruction" 1252 help 1253 The SETEND instruction alters the data-endianness of the 1254 AArch32 EL0, and is deprecated in ARMv8. 1255 1256 Say Y here to enable software emulation of the instruction 1257 for AArch32 userspace code. 1258 1259 Note: All the cpus on the system must have mixed endian support at EL0 1260 for this feature to be enabled. If a new CPU - which doesn't support mixed 1261 endian - is hotplugged in after this feature has been enabled, there could 1262 be unexpected results in the applications. 1263 1264 If unsure, say Y 1265endif 1266 1267endif 1268 1269menu "ARMv8.1 architectural features" 1270 1271config ARM64_HW_AFDBM 1272 bool "Support for hardware updates of the Access and Dirty page flags" 1273 default y 1274 help 1275 The ARMv8.1 architecture extensions introduce support for 1276 hardware updates of the access and dirty information in page 1277 table entries. When enabled in TCR_EL1 (HA and HD bits) on 1278 capable processors, accesses to pages with PTE_AF cleared will 1279 set this bit instead of raising an access flag fault. 1280 Similarly, writes to read-only pages with the DBM bit set will 1281 clear the read-only bit (AP[2]) instead of raising a 1282 permission fault. 1283 1284 Kernels built with this configuration option enabled continue 1285 to work on pre-ARMv8.1 hardware and the performance impact is 1286 minimal. If unsure, say Y. 1287 1288config ARM64_PAN 1289 bool "Enable support for Privileged Access Never (PAN)" 1290 default y 1291 help 1292 Privileged Access Never (PAN; part of the ARMv8.1 Extensions) 1293 prevents the kernel or hypervisor from accessing user-space (EL0) 1294 memory directly. 1295 1296 Choosing this option will cause any unprotected (not using 1297 copy_to_user et al) memory access to fail with a permission fault. 1298 1299 The feature is detected at runtime, and will remain as a 'nop' 1300 instruction if the cpu does not implement the feature. 1301 1302config ARM64_LSE_ATOMICS 1303 bool "Atomic instructions" 1304 depends on JUMP_LABEL 1305 default y 1306 help 1307 As part of the Large System Extensions, ARMv8.1 introduces new 1308 atomic instructions that are designed specifically to scale in 1309 very large systems. 1310 1311 Say Y here to make use of these instructions for the in-kernel 1312 atomic routines. This incurs a small overhead on CPUs that do 1313 not support these instructions and requires the kernel to be 1314 built with binutils >= 2.25 in order for the new instructions 1315 to be used. 1316 1317config ARM64_VHE 1318 bool "Enable support for Virtualization Host Extensions (VHE)" 1319 default y 1320 help 1321 Virtualization Host Extensions (VHE) allow the kernel to run 1322 directly at EL2 (instead of EL1) on processors that support 1323 it. This leads to better performance for KVM, as they reduce 1324 the cost of the world switch. 1325 1326 Selecting this option allows the VHE feature to be detected 1327 at runtime, and does not affect processors that do not 1328 implement this feature. 1329 1330endmenu 1331 1332menu "ARMv8.2 architectural features" 1333 1334config ARM64_UAO 1335 bool "Enable support for User Access Override (UAO)" 1336 default y 1337 help 1338 User Access Override (UAO; part of the ARMv8.2 Extensions) 1339 causes the 'unprivileged' variant of the load/store instructions to 1340 be overridden to be privileged. 1341 1342 This option changes get_user() and friends to use the 'unprivileged' 1343 variant of the load/store instructions. This ensures that user-space 1344 really did have access to the supplied memory. When addr_limit is 1345 set to kernel memory the UAO bit will be set, allowing privileged 1346 access to kernel memory. 1347 1348 Choosing this option will cause copy_to_user() et al to use user-space 1349 memory permissions. 1350 1351 The feature is detected at runtime, the kernel will use the 1352 regular load/store instructions if the cpu does not implement the 1353 feature. 1354 1355config ARM64_PMEM 1356 bool "Enable support for persistent memory" 1357 select ARCH_HAS_PMEM_API 1358 select ARCH_HAS_UACCESS_FLUSHCACHE 1359 help 1360 Say Y to enable support for the persistent memory API based on the 1361 ARMv8.2 DCPoP feature. 1362 1363 The feature is detected at runtime, and the kernel will use DC CVAC 1364 operations if DC CVAP is not supported (following the behaviour of 1365 DC CVAP itself if the system does not define a point of persistence). 1366 1367config ARM64_RAS_EXTN 1368 bool "Enable support for RAS CPU Extensions" 1369 default y 1370 help 1371 CPUs that support the Reliability, Availability and Serviceability 1372 (RAS) Extensions, part of ARMv8.2 are able to track faults and 1373 errors, classify them and report them to software. 1374 1375 On CPUs with these extensions system software can use additional 1376 barriers to determine if faults are pending and read the 1377 classification from a new set of registers. 1378 1379 Selecting this feature will allow the kernel to use these barriers 1380 and access the new registers if the system supports the extension. 1381 Platform RAS features may additionally depend on firmware support. 1382 1383config ARM64_CNP 1384 bool "Enable support for Common Not Private (CNP) translations" 1385 default y 1386 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN 1387 help 1388 Common Not Private (CNP) allows translation table entries to 1389 be shared between different PEs in the same inner shareable 1390 domain, so the hardware can use this fact to optimise the 1391 caching of such entries in the TLB. 1392 1393 Selecting this option allows the CNP feature to be detected 1394 at runtime, and does not affect PEs that do not implement 1395 this feature. 1396 1397endmenu 1398 1399menu "ARMv8.3 architectural features" 1400 1401config ARM64_PTR_AUTH 1402 bool "Enable support for pointer authentication" 1403 default y 1404 depends on !KVM || ARM64_VHE 1405 help 1406 Pointer authentication (part of the ARMv8.3 Extensions) provides 1407 instructions for signing and authenticating pointers against secret 1408 keys, which can be used to mitigate Return Oriented Programming (ROP) 1409 and other attacks. 1410 1411 This option enables these instructions at EL0 (i.e. for userspace). 1412 1413 Choosing this option will cause the kernel to initialise secret keys 1414 for each process at exec() time, with these keys being 1415 context-switched along with the process. 1416 1417 The feature is detected at runtime. If the feature is not present in 1418 hardware it will not be advertised to userspace/KVM guest nor will it 1419 be enabled. However, KVM guest also require VHE mode and hence 1420 CONFIG_ARM64_VHE=y option to use this feature. 1421 1422endmenu 1423 1424config ARM64_SVE 1425 bool "ARM Scalable Vector Extension support" 1426 default y 1427 depends on !KVM || ARM64_VHE 1428 help 1429 The Scalable Vector Extension (SVE) is an extension to the AArch64 1430 execution state which complements and extends the SIMD functionality 1431 of the base architecture to support much larger vectors and to enable 1432 additional vectorisation opportunities. 1433 1434 To enable use of this extension on CPUs that implement it, say Y. 1435 1436 On CPUs that support the SVE2 extensions, this option will enable 1437 those too. 1438 1439 Note that for architectural reasons, firmware _must_ implement SVE 1440 support when running on SVE capable hardware. The required support 1441 is present in: 1442 1443 * version 1.5 and later of the ARM Trusted Firmware 1444 * the AArch64 boot wrapper since commit 5e1261e08abf 1445 ("bootwrapper: SVE: Enable SVE for EL2 and below"). 1446 1447 For other firmware implementations, consult the firmware documentation 1448 or vendor. 1449 1450 If you need the kernel to boot on SVE-capable hardware with broken 1451 firmware, you may need to say N here until you get your firmware 1452 fixed. Otherwise, you may experience firmware panics or lockups when 1453 booting the kernel. If unsure and you are not observing these 1454 symptoms, you should assume that it is safe to say Y. 1455 1456 CPUs that support SVE are architecturally required to support the 1457 Virtualization Host Extensions (VHE), so the kernel makes no 1458 provision for supporting SVE alongside KVM without VHE enabled. 1459 Thus, you will need to enable CONFIG_ARM64_VHE if you want to support 1460 KVM in the same kernel image. 1461 1462config ARM64_MODULE_PLTS 1463 bool "Use PLTs to allow module memory to spill over into vmalloc area" 1464 depends on MODULES 1465 select HAVE_MOD_ARCH_SPECIFIC 1466 help 1467 Allocate PLTs when loading modules so that jumps and calls whose 1468 targets are too far away for their relative offsets to be encoded 1469 in the instructions themselves can be bounced via veneers in the 1470 module's PLT. This allows modules to be allocated in the generic 1471 vmalloc area after the dedicated module memory area has been 1472 exhausted. 1473 1474 When running with address space randomization (KASLR), the module 1475 region itself may be too far away for ordinary relative jumps and 1476 calls, and so in that case, module PLTs are required and cannot be 1477 disabled. 1478 1479 Specific errata workaround(s) might also force module PLTs to be 1480 enabled (ARM64_ERRATUM_843419). 1481 1482config ARM64_PSEUDO_NMI 1483 bool "Support for NMI-like interrupts" 1484 select CONFIG_ARM_GIC_V3 1485 help 1486 Adds support for mimicking Non-Maskable Interrupts through the use of 1487 GIC interrupt priority. This support requires version 3 or later of 1488 ARM GIC. 1489 1490 This high priority configuration for interrupts needs to be 1491 explicitly enabled by setting the kernel parameter 1492 "irqchip.gicv3_pseudo_nmi" to 1. 1493 1494 If unsure, say N 1495 1496if ARM64_PSEUDO_NMI 1497config ARM64_DEBUG_PRIORITY_MASKING 1498 bool "Debug interrupt priority masking" 1499 help 1500 This adds runtime checks to functions enabling/disabling 1501 interrupts when using priority masking. The additional checks verify 1502 the validity of ICC_PMR_EL1 when calling concerned functions. 1503 1504 If unsure, say N 1505endif 1506 1507config RELOCATABLE 1508 bool 1509 select ARCH_HAS_RELR 1510 help 1511 This builds the kernel as a Position Independent Executable (PIE), 1512 which retains all relocation metadata required to relocate the 1513 kernel binary at runtime to a different virtual address than the 1514 address it was linked at. 1515 Since AArch64 uses the RELA relocation format, this requires a 1516 relocation pass at runtime even if the kernel is loaded at the 1517 same address it was linked at. 1518 1519config RANDOMIZE_BASE 1520 bool "Randomize the address of the kernel image" 1521 select ARM64_MODULE_PLTS if MODULES 1522 select RELOCATABLE 1523 help 1524 Randomizes the virtual address at which the kernel image is 1525 loaded, as a security feature that deters exploit attempts 1526 relying on knowledge of the location of kernel internals. 1527 1528 It is the bootloader's job to provide entropy, by passing a 1529 random u64 value in /chosen/kaslr-seed at kernel entry. 1530 1531 When booting via the UEFI stub, it will invoke the firmware's 1532 EFI_RNG_PROTOCOL implementation (if available) to supply entropy 1533 to the kernel proper. In addition, it will randomise the physical 1534 location of the kernel Image as well. 1535 1536 If unsure, say N. 1537 1538config RANDOMIZE_MODULE_REGION_FULL 1539 bool "Randomize the module region over a 4 GB range" 1540 depends on RANDOMIZE_BASE 1541 default y 1542 help 1543 Randomizes the location of the module region inside a 4 GB window 1544 covering the core kernel. This way, it is less likely for modules 1545 to leak information about the location of core kernel data structures 1546 but it does imply that function calls between modules and the core 1547 kernel will need to be resolved via veneers in the module PLT. 1548 1549 When this option is not set, the module region will be randomized over 1550 a limited range that contains the [_stext, _etext] interval of the 1551 core kernel, so branch relocations are always in range. 1552 1553config CC_HAVE_STACKPROTECTOR_SYSREG 1554 def_bool $(cc-option,-mstack-protector-guard=sysreg -mstack-protector-guard-reg=sp_el0 -mstack-protector-guard-offset=0) 1555 1556config STACKPROTECTOR_PER_TASK 1557 def_bool y 1558 depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_SYSREG 1559 1560endmenu 1561 1562menu "Boot options" 1563 1564config ARM64_ACPI_PARKING_PROTOCOL 1565 bool "Enable support for the ARM64 ACPI parking protocol" 1566 depends on ACPI 1567 help 1568 Enable support for the ARM64 ACPI parking protocol. If disabled 1569 the kernel will not allow booting through the ARM64 ACPI parking 1570 protocol even if the corresponding data is present in the ACPI 1571 MADT table. 1572 1573config CMDLINE 1574 string "Default kernel command string" 1575 default "" 1576 help 1577 Provide a set of default command-line options at build time by 1578 entering them here. As a minimum, you should specify the the 1579 root device (e.g. root=/dev/nfs). 1580 1581config CMDLINE_FORCE 1582 bool "Always use the default kernel command string" 1583 help 1584 Always use the default kernel command string, even if the boot 1585 loader passes other arguments to the kernel. 1586 This is useful if you cannot or don't want to change the 1587 command-line options your boot loader passes to the kernel. 1588 1589config EFI_STUB 1590 bool 1591 1592config EFI 1593 bool "UEFI runtime support" 1594 depends on OF && !CPU_BIG_ENDIAN 1595 depends on KERNEL_MODE_NEON 1596 select ARCH_SUPPORTS_ACPI 1597 select LIBFDT 1598 select UCS2_STRING 1599 select EFI_PARAMS_FROM_FDT 1600 select EFI_RUNTIME_WRAPPERS 1601 select EFI_STUB 1602 select EFI_ARMSTUB 1603 default y 1604 help 1605 This option provides support for runtime services provided 1606 by UEFI firmware (such as non-volatile variables, realtime 1607 clock, and platform reset). A UEFI stub is also provided to 1608 allow the kernel to be booted as an EFI application. This 1609 is only useful on systems that have UEFI firmware. 1610 1611config DMI 1612 bool "Enable support for SMBIOS (DMI) tables" 1613 depends on EFI 1614 default y 1615 help 1616 This enables SMBIOS/DMI feature for systems. 1617 1618 This option is only useful on systems that have UEFI firmware. 1619 However, even with this option, the resultant kernel should 1620 continue to boot on existing non-UEFI platforms. 1621 1622endmenu 1623 1624config SYSVIPC_COMPAT 1625 def_bool y 1626 depends on COMPAT && SYSVIPC 1627 1628config ARCH_ENABLE_HUGEPAGE_MIGRATION 1629 def_bool y 1630 depends on HUGETLB_PAGE && MIGRATION 1631 1632menu "Power management options" 1633 1634source "kernel/power/Kconfig" 1635 1636config ARCH_HIBERNATION_POSSIBLE 1637 def_bool y 1638 depends on CPU_PM 1639 1640config ARCH_HIBERNATION_HEADER 1641 def_bool y 1642 depends on HIBERNATION 1643 1644config ARCH_SUSPEND_POSSIBLE 1645 def_bool y 1646 1647endmenu 1648 1649menu "CPU Power Management" 1650 1651source "drivers/cpuidle/Kconfig" 1652 1653source "drivers/cpufreq/Kconfig" 1654 1655endmenu 1656 1657source "drivers/firmware/Kconfig" 1658 1659source "drivers/acpi/Kconfig" 1660 1661source "arch/arm64/kvm/Kconfig" 1662 1663if CRYPTO 1664source "arch/arm64/crypto/Kconfig" 1665endif 1666