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_HAS_DEBUG_WX 13 select ARCH_BINFMT_ELF_STATE 14 select ARCH_HAS_DEBUG_VIRTUAL 15 select ARCH_HAS_DEBUG_VM_PGTABLE 16 select ARCH_HAS_DEVMEM_IS_ALLOWED 17 select ARCH_HAS_DMA_PREP_COHERENT 18 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 19 select ARCH_HAS_FAST_MULTIPLIER 20 select ARCH_HAS_FORTIFY_SOURCE 21 select ARCH_HAS_GCOV_PROFILE_ALL 22 select ARCH_HAS_GIGANTIC_PAGE 23 select ARCH_HAS_KCOV 24 select ARCH_HAS_KEEPINITRD 25 select ARCH_HAS_MEMBARRIER_SYNC_CORE 26 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 27 select ARCH_HAS_PTE_DEVMAP 28 select ARCH_HAS_PTE_SPECIAL 29 select ARCH_HAS_SETUP_DMA_OPS 30 select ARCH_HAS_SET_DIRECT_MAP 31 select ARCH_HAS_SET_MEMORY 32 select ARCH_STACKWALK 33 select ARCH_HAS_STRICT_KERNEL_RWX 34 select ARCH_HAS_STRICT_MODULE_RWX 35 select ARCH_HAS_SYNC_DMA_FOR_DEVICE 36 select ARCH_HAS_SYNC_DMA_FOR_CPU 37 select ARCH_HAS_SYSCALL_WRAPPER 38 select ARCH_HAS_TEARDOWN_DMA_OPS if IOMMU_SUPPORT 39 select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST 40 select ARCH_HAVE_ELF_PROT 41 select ARCH_HAVE_NMI_SAFE_CMPXCHG 42 select ARCH_INLINE_READ_LOCK if !PREEMPTION 43 select ARCH_INLINE_READ_LOCK_BH if !PREEMPTION 44 select ARCH_INLINE_READ_LOCK_IRQ if !PREEMPTION 45 select ARCH_INLINE_READ_LOCK_IRQSAVE if !PREEMPTION 46 select ARCH_INLINE_READ_UNLOCK if !PREEMPTION 47 select ARCH_INLINE_READ_UNLOCK_BH if !PREEMPTION 48 select ARCH_INLINE_READ_UNLOCK_IRQ if !PREEMPTION 49 select ARCH_INLINE_READ_UNLOCK_IRQRESTORE if !PREEMPTION 50 select ARCH_INLINE_WRITE_LOCK if !PREEMPTION 51 select ARCH_INLINE_WRITE_LOCK_BH if !PREEMPTION 52 select ARCH_INLINE_WRITE_LOCK_IRQ if !PREEMPTION 53 select ARCH_INLINE_WRITE_LOCK_IRQSAVE if !PREEMPTION 54 select ARCH_INLINE_WRITE_UNLOCK if !PREEMPTION 55 select ARCH_INLINE_WRITE_UNLOCK_BH if !PREEMPTION 56 select ARCH_INLINE_WRITE_UNLOCK_IRQ if !PREEMPTION 57 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE if !PREEMPTION 58 select ARCH_INLINE_SPIN_TRYLOCK if !PREEMPTION 59 select ARCH_INLINE_SPIN_TRYLOCK_BH if !PREEMPTION 60 select ARCH_INLINE_SPIN_LOCK if !PREEMPTION 61 select ARCH_INLINE_SPIN_LOCK_BH if !PREEMPTION 62 select ARCH_INLINE_SPIN_LOCK_IRQ if !PREEMPTION 63 select ARCH_INLINE_SPIN_LOCK_IRQSAVE if !PREEMPTION 64 select ARCH_INLINE_SPIN_UNLOCK if !PREEMPTION 65 select ARCH_INLINE_SPIN_UNLOCK_BH if !PREEMPTION 66 select ARCH_INLINE_SPIN_UNLOCK_IRQ if !PREEMPTION 67 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPTION 68 select ARCH_KEEP_MEMBLOCK 69 select ARCH_USE_CMPXCHG_LOCKREF 70 select ARCH_USE_GNU_PROPERTY 71 select ARCH_USE_QUEUED_RWLOCKS 72 select ARCH_USE_QUEUED_SPINLOCKS 73 select ARCH_USE_SYM_ANNOTATIONS 74 select ARCH_SUPPORTS_MEMORY_FAILURE 75 select ARCH_SUPPORTS_SHADOW_CALL_STACK if CC_HAVE_SHADOW_CALL_STACK 76 select ARCH_SUPPORTS_LTO_CLANG if CPU_LITTLE_ENDIAN 77 select ARCH_SUPPORTS_LTO_CLANG_THIN 78 select ARCH_SUPPORTS_ATOMIC_RMW 79 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && (GCC_VERSION >= 50000 || CC_IS_CLANG) 80 select ARCH_SUPPORTS_NUMA_BALANCING 81 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT 82 select ARCH_WANT_DEFAULT_BPF_JIT 83 select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT 84 select ARCH_WANT_FRAME_POINTERS 85 select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36) 86 select ARCH_WANT_LD_ORPHAN_WARN 87 select ARCH_HAS_UBSAN_SANITIZE_ALL 88 select ARM_AMBA 89 select ARM_ARCH_TIMER 90 select ARM_GIC 91 select AUDIT_ARCH_COMPAT_GENERIC 92 select ARM_GIC_V2M if PCI 93 select ARM_GIC_V3 94 select ARM_GIC_V3_ITS if PCI 95 select ARM_PSCI_FW 96 select BUILDTIME_TABLE_SORT 97 select CLONE_BACKWARDS 98 select COMMON_CLK 99 select CPU_PM if (SUSPEND || CPU_IDLE) 100 select CRC32 101 select DCACHE_WORD_ACCESS 102 select DMA_DIRECT_REMAP 103 select EDAC_SUPPORT 104 select FRAME_POINTER 105 select GENERIC_ALLOCATOR 106 select GENERIC_ARCH_TOPOLOGY 107 select GENERIC_CLOCKEVENTS 108 select GENERIC_CLOCKEVENTS_BROADCAST 109 select GENERIC_CPU_AUTOPROBE 110 select GENERIC_CPU_VULNERABILITIES 111 select GENERIC_EARLY_IOREMAP 112 select GENERIC_IDLE_POLL_SETUP 113 select GENERIC_IRQ_IPI 114 select ARCH_WANTS_IRQ_RAW 115 select GENERIC_IRQ_MULTI_HANDLER 116 select GENERIC_IRQ_PROBE 117 select GENERIC_IRQ_SHOW 118 select GENERIC_IRQ_SHOW_LEVEL 119 select GENERIC_PCI_IOMAP 120 select GENERIC_PTDUMP 121 select GENERIC_SCHED_CLOCK 122 select GENERIC_SMP_IDLE_THREAD 123 select GENERIC_STRNCPY_FROM_USER 124 select GENERIC_STRNLEN_USER 125 select GENERIC_TIME_VSYSCALL 126 select GENERIC_GETTIMEOFDAY 127 select GENERIC_VDSO_TIME_NS 128 select HANDLE_DOMAIN_IRQ 129 select HARDIRQS_SW_RESEND 130 select HAVE_MOVE_PMD 131 select HAVE_MOVE_PUD 132 select HAVE_PCI 133 select HAVE_ACPI_APEI if (ACPI && EFI) 134 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 135 select HAVE_ARCH_AUDITSYSCALL 136 select HAVE_ARCH_BITREVERSE 137 select HAVE_ARCH_COMPILER_H 138 select HAVE_ARCH_HUGE_VMAP 139 select HAVE_ARCH_JUMP_LABEL 140 select HAVE_ARCH_JUMP_LABEL_RELATIVE 141 select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48) 142 select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN 143 select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN 144 select HAVE_ARCH_KASAN_HW_TAGS if (HAVE_ARCH_KASAN && ARM64_MTE) 145 select HAVE_ARCH_KFENCE 146 select HAVE_ARCH_KGDB 147 select HAVE_ARCH_MMAP_RND_BITS 148 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT 149 select HAVE_ARCH_PREL32_RELOCATIONS 150 select HAVE_ARCH_SECCOMP_FILTER 151 select HAVE_ARCH_STACKLEAK 152 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 153 select HAVE_ARCH_TRACEHOOK 154 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 155 select HAVE_ARCH_VMAP_STACK 156 select HAVE_ARM_SMCCC 157 select HAVE_ASM_MODVERSIONS 158 select HAVE_EBPF_JIT 159 select HAVE_C_RECORDMCOUNT 160 select HAVE_CMPXCHG_DOUBLE 161 select HAVE_CMPXCHG_LOCAL 162 select HAVE_CONTEXT_TRACKING 163 select HAVE_DEBUG_BUGVERBOSE 164 select HAVE_DEBUG_KMEMLEAK 165 select HAVE_DMA_CONTIGUOUS 166 select HAVE_DYNAMIC_FTRACE 167 select HAVE_DYNAMIC_FTRACE_WITH_REGS \ 168 if $(cc-option,-fpatchable-function-entry=2) 169 select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY \ 170 if DYNAMIC_FTRACE_WITH_REGS 171 select HAVE_EFFICIENT_UNALIGNED_ACCESS 172 select HAVE_FAST_GUP 173 select HAVE_FTRACE_MCOUNT_RECORD 174 select HAVE_FUNCTION_TRACER 175 select HAVE_FUNCTION_ERROR_INJECTION 176 select HAVE_FUNCTION_GRAPH_TRACER 177 select HAVE_GCC_PLUGINS 178 select HAVE_HW_BREAKPOINT if PERF_EVENTS 179 select HAVE_IRQ_TIME_ACCOUNTING 180 select HAVE_NMI 181 select HAVE_PATA_PLATFORM 182 select HAVE_PERF_EVENTS 183 select HAVE_PERF_REGS 184 select HAVE_PERF_USER_STACK_DUMP 185 select HAVE_REGS_AND_STACK_ACCESS_API 186 select HAVE_FUNCTION_ARG_ACCESS_API 187 select HAVE_FUTEX_CMPXCHG if FUTEX 188 select MMU_GATHER_RCU_TABLE_FREE 189 select HAVE_RSEQ 190 select HAVE_STACKPROTECTOR 191 select HAVE_SYSCALL_TRACEPOINTS 192 select HAVE_KPROBES 193 select HAVE_KRETPROBES 194 select HAVE_GENERIC_VDSO 195 select IOMMU_DMA if IOMMU_SUPPORT 196 select IRQ_DOMAIN 197 select IRQ_FORCED_THREADING 198 select KASAN_VMALLOC if KASAN_GENERIC 199 select MODULES_USE_ELF_RELA 200 select NEED_DMA_MAP_STATE 201 select NEED_SG_DMA_LENGTH 202 select OF 203 select OF_EARLY_FLATTREE 204 select PCI_DOMAINS_GENERIC if PCI 205 select PCI_ECAM if (ACPI && PCI) 206 select PCI_SYSCALL if PCI 207 select POWER_RESET 208 select POWER_SUPPLY 209 select SET_FS 210 select SPARSE_IRQ 211 select SWIOTLB 212 select SYSCTL_EXCEPTION_TRACE 213 select THREAD_INFO_IN_TASK 214 select ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT 215 select HAVE_ARCH_USERFAULTFD_MINOR if USERFAULTFD 216 help 217 ARM 64-bit (AArch64) Linux support. 218 219config 64BIT 220 def_bool y 221 222config MMU 223 def_bool y 224 225config ARM64_PAGE_SHIFT 226 int 227 default 16 if ARM64_64K_PAGES 228 default 14 if ARM64_16K_PAGES 229 default 12 230 231config ARM64_CONT_PTE_SHIFT 232 int 233 default 5 if ARM64_64K_PAGES 234 default 7 if ARM64_16K_PAGES 235 default 4 236 237config ARM64_CONT_PMD_SHIFT 238 int 239 default 5 if ARM64_64K_PAGES 240 default 5 if ARM64_16K_PAGES 241 default 4 242 243config ARCH_MMAP_RND_BITS_MIN 244 default 14 if ARM64_64K_PAGES 245 default 16 if ARM64_16K_PAGES 246 default 18 247 248# max bits determined by the following formula: 249# VA_BITS - PAGE_SHIFT - 3 250config ARCH_MMAP_RND_BITS_MAX 251 default 19 if ARM64_VA_BITS=36 252 default 24 if ARM64_VA_BITS=39 253 default 27 if ARM64_VA_BITS=42 254 default 30 if ARM64_VA_BITS=47 255 default 29 if ARM64_VA_BITS=48 && ARM64_64K_PAGES 256 default 31 if ARM64_VA_BITS=48 && ARM64_16K_PAGES 257 default 33 if ARM64_VA_BITS=48 258 default 14 if ARM64_64K_PAGES 259 default 16 if ARM64_16K_PAGES 260 default 18 261 262config ARCH_MMAP_RND_COMPAT_BITS_MIN 263 default 7 if ARM64_64K_PAGES 264 default 9 if ARM64_16K_PAGES 265 default 11 266 267config ARCH_MMAP_RND_COMPAT_BITS_MAX 268 default 16 269 270config NO_IOPORT_MAP 271 def_bool y if !PCI 272 273config STACKTRACE_SUPPORT 274 def_bool y 275 276config ILLEGAL_POINTER_VALUE 277 hex 278 default 0xdead000000000000 279 280config LOCKDEP_SUPPORT 281 def_bool y 282 283config TRACE_IRQFLAGS_SUPPORT 284 def_bool y 285 286config GENERIC_BUG 287 def_bool y 288 depends on BUG 289 290config GENERIC_BUG_RELATIVE_POINTERS 291 def_bool y 292 depends on GENERIC_BUG 293 294config GENERIC_HWEIGHT 295 def_bool y 296 297config GENERIC_CSUM 298 def_bool y 299 300config GENERIC_CALIBRATE_DELAY 301 def_bool y 302 303config ZONE_DMA 304 bool "Support DMA zone" if EXPERT 305 default y 306 307config ZONE_DMA32 308 bool "Support DMA32 zone" if EXPERT 309 default y 310 311config ARCH_ENABLE_MEMORY_HOTPLUG 312 def_bool y 313 314config ARCH_ENABLE_MEMORY_HOTREMOVE 315 def_bool y 316 317config SMP 318 def_bool y 319 320config KERNEL_MODE_NEON 321 def_bool y 322 323config FIX_EARLYCON_MEM 324 def_bool y 325 326config PGTABLE_LEVELS 327 int 328 default 2 if ARM64_16K_PAGES && ARM64_VA_BITS_36 329 default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42 330 default 3 if ARM64_64K_PAGES && (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) 331 default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39 332 default 3 if ARM64_16K_PAGES && ARM64_VA_BITS_47 333 default 4 if !ARM64_64K_PAGES && ARM64_VA_BITS_48 334 335config ARCH_SUPPORTS_UPROBES 336 def_bool y 337 338config ARCH_PROC_KCORE_TEXT 339 def_bool y 340 341config BROKEN_GAS_INST 342 def_bool !$(as-instr,1:\n.inst 0\n.rept . - 1b\n\nnop\n.endr\n) 343 344config KASAN_SHADOW_OFFSET 345 hex 346 depends on KASAN_GENERIC || KASAN_SW_TAGS 347 default 0xdfffa00000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && !KASAN_SW_TAGS 348 default 0xdfffd00000000000 if ARM64_VA_BITS_47 && !KASAN_SW_TAGS 349 default 0xdffffe8000000000 if ARM64_VA_BITS_42 && !KASAN_SW_TAGS 350 default 0xdfffffd000000000 if ARM64_VA_BITS_39 && !KASAN_SW_TAGS 351 default 0xdffffffa00000000 if ARM64_VA_BITS_36 && !KASAN_SW_TAGS 352 default 0xefff900000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && KASAN_SW_TAGS 353 default 0xefffc80000000000 if ARM64_VA_BITS_47 && KASAN_SW_TAGS 354 default 0xeffffe4000000000 if ARM64_VA_BITS_42 && KASAN_SW_TAGS 355 default 0xefffffc800000000 if ARM64_VA_BITS_39 && KASAN_SW_TAGS 356 default 0xeffffff900000000 if ARM64_VA_BITS_36 && KASAN_SW_TAGS 357 default 0xffffffffffffffff 358 359source "arch/arm64/Kconfig.platforms" 360 361menu "Kernel Features" 362 363menu "ARM errata workarounds via the alternatives framework" 364 365config ARM64_WORKAROUND_CLEAN_CACHE 366 bool 367 368config ARM64_ERRATUM_826319 369 bool "Cortex-A53: 826319: System might deadlock if a write cannot complete until read data is accepted" 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 826319 on Cortex-A53 parts up to r0p2 with an AMBA 4 ACE or 375 AXI master interface and an L2 cache. 376 377 If a Cortex-A53 uses an AMBA AXI4 ACE interface to other processors 378 and is unable to accept a certain write via this interface, it will 379 not progress on read data presented on the read data channel and the 380 system can deadlock. 381 382 The workaround promotes data cache clean instructions to 383 data cache clean-and-invalidate. 384 Please note that this does not necessarily enable the workaround, 385 as it depends on the alternative framework, which will only patch 386 the kernel if an affected CPU is detected. 387 388 If unsure, say Y. 389 390config ARM64_ERRATUM_827319 391 bool "Cortex-A53: 827319: Data cache clean instructions might cause overlapping transactions to the interconnect" 392 default y 393 select ARM64_WORKAROUND_CLEAN_CACHE 394 help 395 This option adds an alternative code sequence to work around ARM 396 erratum 827319 on Cortex-A53 parts up to r0p2 with an AMBA 5 CHI 397 master interface and an L2 cache. 398 399 Under certain conditions this erratum can cause a clean line eviction 400 to occur at the same time as another transaction to the same address 401 on the AMBA 5 CHI interface, which can cause data corruption if the 402 interconnect reorders the two transactions. 403 404 The workaround promotes data cache clean instructions to 405 data cache clean-and-invalidate. 406 Please note that this does not necessarily enable the workaround, 407 as it depends on the alternative framework, which will only patch 408 the kernel if an affected CPU is detected. 409 410 If unsure, say Y. 411 412config ARM64_ERRATUM_824069 413 bool "Cortex-A53: 824069: Cache line might not be marked as clean after a CleanShared snoop" 414 default y 415 select ARM64_WORKAROUND_CLEAN_CACHE 416 help 417 This option adds an alternative code sequence to work around ARM 418 erratum 824069 on Cortex-A53 parts up to r0p2 when it is connected 419 to a coherent interconnect. 420 421 If a Cortex-A53 processor is executing a store or prefetch for 422 write instruction at the same time as a processor in another 423 cluster is executing a cache maintenance operation to the same 424 address, then this erratum might cause a clean cache line to be 425 incorrectly marked as dirty. 426 427 The workaround promotes data cache clean instructions to 428 data cache clean-and-invalidate. 429 Please note that this option does not necessarily enable the 430 workaround, as it depends on the alternative framework, which will 431 only patch the kernel if an affected CPU is detected. 432 433 If unsure, say Y. 434 435config ARM64_ERRATUM_819472 436 bool "Cortex-A53: 819472: Store exclusive instructions might cause data corruption" 437 default y 438 select ARM64_WORKAROUND_CLEAN_CACHE 439 help 440 This option adds an alternative code sequence to work around ARM 441 erratum 819472 on Cortex-A53 parts up to r0p1 with an L2 cache 442 present when it is connected to a coherent interconnect. 443 444 If the processor is executing a load and store exclusive sequence at 445 the same time as a processor in another cluster is executing a cache 446 maintenance operation to the same address, then this erratum might 447 cause data corruption. 448 449 The workaround promotes data cache clean instructions to 450 data cache clean-and-invalidate. 451 Please note that this does not necessarily enable the workaround, 452 as it depends on the alternative framework, which will only patch 453 the kernel if an affected CPU is detected. 454 455 If unsure, say Y. 456 457config ARM64_ERRATUM_832075 458 bool "Cortex-A57: 832075: possible deadlock on mixing exclusive memory accesses with device loads" 459 default y 460 help 461 This option adds an alternative code sequence to work around ARM 462 erratum 832075 on Cortex-A57 parts up to r1p2. 463 464 Affected Cortex-A57 parts might deadlock when exclusive load/store 465 instructions to Write-Back memory are mixed with Device loads. 466 467 The workaround is to promote device loads to use Load-Acquire 468 semantics. 469 Please note that this does not necessarily enable the workaround, 470 as it depends on the alternative framework, which will only patch 471 the kernel if an affected CPU is detected. 472 473 If unsure, say Y. 474 475config ARM64_ERRATUM_834220 476 bool "Cortex-A57: 834220: Stage 2 translation fault might be incorrectly reported in presence of a Stage 1 fault" 477 depends on KVM 478 default y 479 help 480 This option adds an alternative code sequence to work around ARM 481 erratum 834220 on Cortex-A57 parts up to r1p2. 482 483 Affected Cortex-A57 parts might report a Stage 2 translation 484 fault as the result of a Stage 1 fault for load crossing a 485 page boundary when there is a permission or device memory 486 alignment fault at Stage 1 and a translation fault at Stage 2. 487 488 The workaround is to verify that the Stage 1 translation 489 doesn't generate a fault before handling the Stage 2 fault. 490 Please note that this does not necessarily enable the workaround, 491 as it depends on the alternative framework, which will only patch 492 the kernel if an affected CPU is detected. 493 494 If unsure, say Y. 495 496config ARM64_ERRATUM_1742098 497 bool "Cortex-A57/A72: 1742098: ELR recorded incorrectly on interrupt taken between cryptographic instructions in a sequence" 498 depends on COMPAT 499 default y 500 help 501 This option removes the AES hwcap for aarch32 user-space to 502 workaround erratum 1742098 on Cortex-A57 and Cortex-A72. 503 504 Affected parts may corrupt the AES state if an interrupt is 505 taken between a pair of AES instructions. These instructions 506 are only present if the cryptography extensions are present. 507 All software should have a fallback implementation for CPUs 508 that don't implement the cryptography extensions. 509 510 If unsure, say Y. 511 512config ARM64_ERRATUM_845719 513 bool "Cortex-A53: 845719: a load might read incorrect data" 514 depends on COMPAT 515 default y 516 help 517 This option adds an alternative code sequence to work around ARM 518 erratum 845719 on Cortex-A53 parts up to r0p4. 519 520 When running a compat (AArch32) userspace on an affected Cortex-A53 521 part, a load at EL0 from a virtual address that matches the bottom 32 522 bits of the virtual address used by a recent load at (AArch64) EL1 523 might return incorrect data. 524 525 The workaround is to write the contextidr_el1 register on exception 526 return to a 32-bit task. 527 Please note that this does not necessarily enable the workaround, 528 as it depends on the alternative framework, which will only patch 529 the kernel if an affected CPU is detected. 530 531 If unsure, say Y. 532 533config ARM64_ERRATUM_843419 534 bool "Cortex-A53: 843419: A load or store might access an incorrect address" 535 default y 536 select ARM64_MODULE_PLTS if MODULES 537 help 538 This option links the kernel with '--fix-cortex-a53-843419' and 539 enables PLT support to replace certain ADRP instructions, which can 540 cause subsequent memory accesses to use an incorrect address on 541 Cortex-A53 parts up to r0p4. 542 543 If unsure, say Y. 544 545config ARM64_ERRATUM_1024718 546 bool "Cortex-A55: 1024718: Update of DBM/AP bits without break before make might result in incorrect update" 547 default y 548 help 549 This option adds a workaround for ARM Cortex-A55 Erratum 1024718. 550 551 Affected Cortex-A55 cores (all revisions) could cause incorrect 552 update of the hardware dirty bit when the DBM/AP bits are updated 553 without a break-before-make. The workaround is to disable the usage 554 of hardware DBM locally on the affected cores. CPUs not affected by 555 this erratum will continue to use the feature. 556 557 If unsure, say Y. 558 559config ARM64_ERRATUM_1418040 560 bool "Cortex-A76/Neoverse-N1: MRC read following MRRC read of specific Generic Timer in AArch32 might give incorrect result" 561 default y 562 depends on COMPAT 563 help 564 This option adds a workaround for ARM Cortex-A76/Neoverse-N1 565 errata 1188873 and 1418040. 566 567 Affected Cortex-A76/Neoverse-N1 cores (r0p0 to r3p1) could 568 cause register corruption when accessing the timer registers 569 from AArch32 userspace. 570 571 If unsure, say Y. 572 573config ARM64_WORKAROUND_SPECULATIVE_AT 574 bool 575 576config ARM64_ERRATUM_1165522 577 bool "Cortex-A76: 1165522: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation" 578 default y 579 select ARM64_WORKAROUND_SPECULATIVE_AT 580 help 581 This option adds a workaround for ARM Cortex-A76 erratum 1165522. 582 583 Affected Cortex-A76 cores (r0p0, r1p0, r2p0) could end-up with 584 corrupted TLBs by speculating an AT instruction during a guest 585 context switch. 586 587 If unsure, say Y. 588 589config ARM64_ERRATUM_1319367 590 bool "Cortex-A57/A72: 1319537: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation" 591 default y 592 select ARM64_WORKAROUND_SPECULATIVE_AT 593 help 594 This option adds work arounds for ARM Cortex-A57 erratum 1319537 595 and A72 erratum 1319367 596 597 Cortex-A57 and A72 cores could end-up with corrupted TLBs by 598 speculating an AT instruction during a guest context switch. 599 600 If unsure, say Y. 601 602config ARM64_ERRATUM_1530923 603 bool "Cortex-A55: 1530923: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation" 604 default y 605 select ARM64_WORKAROUND_SPECULATIVE_AT 606 help 607 This option adds a workaround for ARM Cortex-A55 erratum 1530923. 608 609 Affected Cortex-A55 cores (r0p0, r0p1, r1p0, r2p0) could end-up with 610 corrupted TLBs by speculating an AT instruction during a guest 611 context switch. 612 613 If unsure, say Y. 614 615config ARM64_WORKAROUND_REPEAT_TLBI 616 bool 617 618config ARM64_ERRATUM_1286807 619 bool "Cortex-A76: Modification of the translation table for a virtual address might lead to read-after-read ordering violation" 620 default y 621 select ARM64_WORKAROUND_REPEAT_TLBI 622 help 623 This option adds a workaround for ARM Cortex-A76 erratum 1286807. 624 625 On the affected Cortex-A76 cores (r0p0 to r3p0), if a virtual 626 address for a cacheable mapping of a location is being 627 accessed by a core while another core is remapping the virtual 628 address to a new physical page using the recommended 629 break-before-make sequence, then under very rare circumstances 630 TLBI+DSB completes before a read using the translation being 631 invalidated has been observed by other observers. The 632 workaround repeats the TLBI+DSB operation. 633 634config ARM64_ERRATUM_1463225 635 bool "Cortex-A76: Software Step might prevent interrupt recognition" 636 default y 637 help 638 This option adds a workaround for Arm Cortex-A76 erratum 1463225. 639 640 On the affected Cortex-A76 cores (r0p0 to r3p1), software stepping 641 of a system call instruction (SVC) can prevent recognition of 642 subsequent interrupts when software stepping is disabled in the 643 exception handler of the system call and either kernel debugging 644 is enabled or VHE is in use. 645 646 Work around the erratum by triggering a dummy step exception 647 when handling a system call from a task that is being stepped 648 in a VHE configuration of the kernel. 649 650 If unsure, say Y. 651 652config ARM64_ERRATUM_1542419 653 bool "Neoverse-N1: workaround mis-ordering of instruction fetches" 654 default y 655 help 656 This option adds a workaround for ARM Neoverse-N1 erratum 657 1542419. 658 659 Affected Neoverse-N1 cores could execute a stale instruction when 660 modified by another CPU. The workaround depends on a firmware 661 counterpart. 662 663 Workaround the issue by hiding the DIC feature from EL0. This 664 forces user-space to perform cache maintenance. 665 666 If unsure, say Y. 667 668config ARM64_ERRATUM_1508412 669 bool "Cortex-A77: 1508412: workaround deadlock on sequence of NC/Device load and store exclusive or PAR read" 670 default y 671 help 672 This option adds a workaround for Arm Cortex-A77 erratum 1508412. 673 674 Affected Cortex-A77 cores (r0p0, r1p0) could deadlock on a sequence 675 of a store-exclusive or read of PAR_EL1 and a load with device or 676 non-cacheable memory attributes. The workaround depends on a firmware 677 counterpart. 678 679 KVM guests must also have the workaround implemented or they can 680 deadlock the system. 681 682 Work around the issue by inserting DMB SY barriers around PAR_EL1 683 register reads and warning KVM users. The DMB barrier is sufficient 684 to prevent a speculative PAR_EL1 read. 685 686 If unsure, say Y. 687 688config ARM64_ERRATUM_2051678 689 bool "Cortex-A510: 2051678: disable Hardware Update of the page table's dirty bit" 690 default y 691 help 692 This options adds the workaround for ARM Cortex-A510 erratum ARM64_ERRATUM_2051678. 693 Affected Coretex-A510 might not respect the ordering rules for 694 hardware update of the page table's dirty bit. The workaround 695 is to not enable the feature on affected CPUs. 696 697 If unsure, say Y. 698 699config ARM64_WORKAROUND_TSB_FLUSH_FAILURE 700 bool 701 702config ARM64_ERRATUM_2054223 703 bool "Cortex-A710: 2054223: workaround TSB instruction failing to flush trace" 704 default y 705 select ARM64_WORKAROUND_TSB_FLUSH_FAILURE 706 help 707 Enable workaround for ARM Cortex-A710 erratum 2054223 708 709 Affected cores may fail to flush the trace data on a TSB instruction, when 710 the PE is in trace prohibited state. This will cause losing a few bytes 711 of the trace cached. 712 713 Workaround is to issue two TSB consecutively on affected cores. 714 715 If unsure, say Y. 716 717config ARM64_ERRATUM_2067961 718 bool "Neoverse-N2: 2067961: workaround TSB instruction failing to flush trace" 719 default y 720 select ARM64_WORKAROUND_TSB_FLUSH_FAILURE 721 help 722 Enable workaround for ARM Neoverse-N2 erratum 2067961 723 724 Affected cores may fail to flush the trace data on a TSB instruction, when 725 the PE is in trace prohibited state. This will cause losing a few bytes 726 of the trace cached. 727 728 Workaround is to issue two TSB consecutively on affected cores. 729 730 If unsure, say Y. 731 732config ARM64_ERRATUM_2454944 733 bool "Cortex-A510: 2454944: Unmodified cache line might be written back to memory" 734 select ARCH_HAS_TEARDOWN_DMA_OPS 735 select RODATA_FULL_DEFAULT_ENABLED 736 help 737 This option adds the workaround for ARM Cortex-A510 erratum 2454944. 738 739 Affected Cortex-A510 core might write unmodified cache lines back to 740 memory, which breaks the assumptions upon which software coherency 741 management for non-coherent DMA relies. If a cache line is 742 speculatively fetched while a non-coherent device is writing directly 743 to DRAM, and subsequently written back by natural eviction, data 744 written by the device in the intervening period can be lost. 745 746 The workaround is to enforce as far as reasonably possible that all 747 non-coherent DMA transfers are bounced and/or remapped to minimise 748 the chance that any Cacheable alias exists through which speculative 749 cache fills could occur. To further improve effectiveness of 750 the workaround, lazy TLB flushing should be disabled. 751 752 This is quite involved and has unavoidable performance impact on 753 affected systems. 754 755config ARM64_ERRATUM_2457168 756 bool "Cortex-A510: 2457168: workaround for AMEVCNTR01 incrementing incorrectly" 757 depends on ARM64_AMU_EXTN 758 default y 759 help 760 This option adds the workaround for ARM Cortex-A510 erratum 2457168. 761 762 The AMU counter AMEVCNTR01 (constant counter) should increment at the same rate 763 as the system counter. On affected Cortex-A510 cores AMEVCNTR01 increments 764 incorrectly giving a significantly higher output value. 765 766 Work around this problem by keeping the reference values of affected counters 767 to 0 thus signaling an error case. This effect is the same to firmware disabling 768 affected counters, in which case 0 will be returned when reading the disabled 769 counters. 770 771 If unsure, say Y. 772 773config CAVIUM_ERRATUM_22375 774 bool "Cavium erratum 22375, 24313" 775 default y 776 help 777 Enable workaround for errata 22375 and 24313. 778 779 This implements two gicv3-its errata workarounds for ThunderX. Both 780 with a small impact affecting only ITS table allocation. 781 782 erratum 22375: only alloc 8MB table size 783 erratum 24313: ignore memory access type 784 785 The fixes are in ITS initialization and basically ignore memory access 786 type and table size provided by the TYPER and BASER registers. 787 788 If unsure, say Y. 789 790config CAVIUM_ERRATUM_23144 791 bool "Cavium erratum 23144: ITS SYNC hang on dual socket system" 792 depends on NUMA 793 default y 794 help 795 ITS SYNC command hang for cross node io and collections/cpu mapping. 796 797 If unsure, say Y. 798 799config CAVIUM_ERRATUM_23154 800 bool "Cavium erratum 23154: Access to ICC_IAR1_EL1 is not sync'ed" 801 default y 802 help 803 The gicv3 of ThunderX requires a modified version for 804 reading the IAR status to ensure data synchronization 805 (access to icc_iar1_el1 is not sync'ed before and after). 806 807 If unsure, say Y. 808 809config CAVIUM_ERRATUM_27456 810 bool "Cavium erratum 27456: Broadcast TLBI instructions may cause icache corruption" 811 default y 812 help 813 On ThunderX T88 pass 1.x through 2.1 parts, broadcast TLBI 814 instructions may cause the icache to become corrupted if it 815 contains data for a non-current ASID. The fix is to 816 invalidate the icache when changing the mm context. 817 818 If unsure, say Y. 819 820config CAVIUM_ERRATUM_30115 821 bool "Cavium erratum 30115: Guest may disable interrupts in host" 822 default y 823 help 824 On ThunderX T88 pass 1.x through 2.2, T81 pass 1.0 through 825 1.2, and T83 Pass 1.0, KVM guest execution may disable 826 interrupts in host. Trapping both GICv3 group-0 and group-1 827 accesses sidesteps the issue. 828 829 If unsure, say Y. 830 831config CAVIUM_TX2_ERRATUM_219 832 bool "Cavium ThunderX2 erratum 219: PRFM between TTBR change and ISB fails" 833 default y 834 help 835 On Cavium ThunderX2, a load, store or prefetch instruction between a 836 TTBR update and the corresponding context synchronizing operation can 837 cause a spurious Data Abort to be delivered to any hardware thread in 838 the CPU core. 839 840 Work around the issue by avoiding the problematic code sequence and 841 trapping KVM guest TTBRx_EL1 writes to EL2 when SMT is enabled. The 842 trap handler performs the corresponding register access, skips the 843 instruction and ensures context synchronization by virtue of the 844 exception return. 845 846 If unsure, say Y. 847 848config FUJITSU_ERRATUM_010001 849 bool "Fujitsu-A64FX erratum E#010001: Undefined fault may occur wrongly" 850 default y 851 help 852 This option adds a workaround for Fujitsu-A64FX erratum E#010001. 853 On some variants of the Fujitsu-A64FX cores ver(1.0, 1.1), memory 854 accesses may cause undefined fault (Data abort, DFSC=0b111111). 855 This fault occurs under a specific hardware condition when a 856 load/store instruction performs an address translation using: 857 case-1 TTBR0_EL1 with TCR_EL1.NFD0 == 1. 858 case-2 TTBR0_EL2 with TCR_EL2.NFD0 == 1. 859 case-3 TTBR1_EL1 with TCR_EL1.NFD1 == 1. 860 case-4 TTBR1_EL2 with TCR_EL2.NFD1 == 1. 861 862 The workaround is to ensure these bits are clear in TCR_ELx. 863 The workaround only affects the Fujitsu-A64FX. 864 865 If unsure, say Y. 866 867config HISILICON_ERRATUM_161600802 868 bool "Hip07 161600802: Erroneous redistributor VLPI base" 869 default y 870 help 871 The HiSilicon Hip07 SoC uses the wrong redistributor base 872 when issued ITS commands such as VMOVP and VMAPP, and requires 873 a 128kB offset to be applied to the target address in this commands. 874 875 If unsure, say Y. 876 877config QCOM_FALKOR_ERRATUM_1003 878 bool "Falkor E1003: Incorrect translation due to ASID change" 879 default y 880 help 881 On Falkor v1, an incorrect ASID may be cached in the TLB when ASID 882 and BADDR are changed together in TTBRx_EL1. Since we keep the ASID 883 in TTBR1_EL1, this situation only occurs in the entry trampoline and 884 then only for entries in the walk cache, since the leaf translation 885 is unchanged. Work around the erratum by invalidating the walk cache 886 entries for the trampoline before entering the kernel proper. 887 888config QCOM_FALKOR_ERRATUM_1009 889 bool "Falkor E1009: Prematurely complete a DSB after a TLBI" 890 default y 891 select ARM64_WORKAROUND_REPEAT_TLBI 892 help 893 On Falkor v1, the CPU may prematurely complete a DSB following a 894 TLBI xxIS invalidate maintenance operation. Repeat the TLBI operation 895 one more time to fix the issue. 896 897 If unsure, say Y. 898 899config QCOM_QDF2400_ERRATUM_0065 900 bool "QDF2400 E0065: Incorrect GITS_TYPER.ITT_Entry_size" 901 default y 902 help 903 On Qualcomm Datacenter Technologies QDF2400 SoC, ITS hardware reports 904 ITE size incorrectly. The GITS_TYPER.ITT_Entry_size field should have 905 been indicated as 16Bytes (0xf), not 8Bytes (0x7). 906 907 If unsure, say Y. 908 909config QCOM_FALKOR_ERRATUM_E1041 910 bool "Falkor E1041: Speculative instruction fetches might cause errant memory access" 911 default y 912 help 913 Falkor CPU may speculatively fetch instructions from an improper 914 memory location when MMU translation is changed from SCTLR_ELn[M]=1 915 to SCTLR_ELn[M]=0. Prefix an ISB instruction to fix the problem. 916 917 If unsure, say Y. 918 919config SOCIONEXT_SYNQUACER_PREITS 920 bool "Socionext Synquacer: Workaround for GICv3 pre-ITS" 921 default y 922 help 923 Socionext Synquacer SoCs implement a separate h/w block to generate 924 MSI doorbell writes with non-zero values for the device ID. 925 926 If unsure, say Y. 927 928endmenu 929 930 931choice 932 prompt "Page size" 933 default ARM64_4K_PAGES 934 help 935 Page size (translation granule) configuration. 936 937config ARM64_4K_PAGES 938 bool "4KB" 939 help 940 This feature enables 4KB pages support. 941 942config ARM64_16K_PAGES 943 bool "16KB" 944 help 945 The system will use 16KB pages support. AArch32 emulation 946 requires applications compiled with 16K (or a multiple of 16K) 947 aligned segments. 948 949config ARM64_64K_PAGES 950 bool "64KB" 951 help 952 This feature enables 64KB pages support (4KB by default) 953 allowing only two levels of page tables and faster TLB 954 look-up. AArch32 emulation requires applications compiled 955 with 64K aligned segments. 956 957endchoice 958 959choice 960 prompt "Virtual address space size" 961 default ARM64_VA_BITS_39 if ARM64_4K_PAGES 962 default ARM64_VA_BITS_47 if ARM64_16K_PAGES 963 default ARM64_VA_BITS_42 if ARM64_64K_PAGES 964 help 965 Allows choosing one of multiple possible virtual address 966 space sizes. The level of translation table is determined by 967 a combination of page size and virtual address space size. 968 969config ARM64_VA_BITS_36 970 bool "36-bit" if EXPERT 971 depends on ARM64_16K_PAGES 972 973config ARM64_VA_BITS_39 974 bool "39-bit" 975 depends on ARM64_4K_PAGES 976 977config ARM64_VA_BITS_42 978 bool "42-bit" 979 depends on ARM64_64K_PAGES 980 981config ARM64_VA_BITS_47 982 bool "47-bit" 983 depends on ARM64_16K_PAGES 984 985config ARM64_VA_BITS_48 986 bool "48-bit" 987 988config ARM64_VA_BITS_52 989 bool "52-bit" 990 depends on ARM64_64K_PAGES && (ARM64_PAN || !ARM64_SW_TTBR0_PAN) 991 help 992 Enable 52-bit virtual addressing for userspace when explicitly 993 requested via a hint to mmap(). The kernel will also use 52-bit 994 virtual addresses for its own mappings (provided HW support for 995 this feature is available, otherwise it reverts to 48-bit). 996 997 NOTE: Enabling 52-bit virtual addressing in conjunction with 998 ARMv8.3 Pointer Authentication will result in the PAC being 999 reduced from 7 bits to 3 bits, which may have a significant 1000 impact on its susceptibility to brute-force attacks. 1001 1002 If unsure, select 48-bit virtual addressing instead. 1003 1004endchoice 1005 1006config ARM64_FORCE_52BIT 1007 bool "Force 52-bit virtual addresses for userspace" 1008 depends on ARM64_VA_BITS_52 && EXPERT 1009 help 1010 For systems with 52-bit userspace VAs enabled, the kernel will attempt 1011 to maintain compatibility with older software by providing 48-bit VAs 1012 unless a hint is supplied to mmap. 1013 1014 This configuration option disables the 48-bit compatibility logic, and 1015 forces all userspace addresses to be 52-bit on HW that supports it. One 1016 should only enable this configuration option for stress testing userspace 1017 memory management code. If unsure say N here. 1018 1019config ARM64_VA_BITS 1020 int 1021 default 36 if ARM64_VA_BITS_36 1022 default 39 if ARM64_VA_BITS_39 1023 default 42 if ARM64_VA_BITS_42 1024 default 47 if ARM64_VA_BITS_47 1025 default 48 if ARM64_VA_BITS_48 1026 default 52 if ARM64_VA_BITS_52 1027 1028choice 1029 prompt "Physical address space size" 1030 default ARM64_PA_BITS_48 1031 help 1032 Choose the maximum physical address range that the kernel will 1033 support. 1034 1035config ARM64_PA_BITS_48 1036 bool "48-bit" 1037 1038config ARM64_PA_BITS_52 1039 bool "52-bit (ARMv8.2)" 1040 depends on ARM64_64K_PAGES 1041 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN 1042 help 1043 Enable support for a 52-bit physical address space, introduced as 1044 part of the ARMv8.2-LPA extension. 1045 1046 With this enabled, the kernel will also continue to work on CPUs that 1047 do not support ARMv8.2-LPA, but with some added memory overhead (and 1048 minor performance overhead). 1049 1050endchoice 1051 1052config ARM64_PA_BITS 1053 int 1054 default 48 if ARM64_PA_BITS_48 1055 default 52 if ARM64_PA_BITS_52 1056 1057choice 1058 prompt "Endianness" 1059 default CPU_LITTLE_ENDIAN 1060 help 1061 Select the endianness of data accesses performed by the CPU. Userspace 1062 applications will need to be compiled and linked for the endianness 1063 that is selected here. 1064 1065config CPU_BIG_ENDIAN 1066 bool "Build big-endian kernel" 1067 depends on !LD_IS_LLD || LLD_VERSION >= 130000 1068 # https://github.com/llvm/llvm-project/commit/1379b150991f70a5782e9a143c2ba5308da1161c 1069 depends on AS_IS_GNU || AS_VERSION >= 150000 1070 help 1071 Say Y if you plan on running a kernel with a big-endian userspace. 1072 1073config CPU_LITTLE_ENDIAN 1074 bool "Build little-endian kernel" 1075 help 1076 Say Y if you plan on running a kernel with a little-endian userspace. 1077 This is usually the case for distributions targeting arm64. 1078 1079endchoice 1080 1081config SCHED_MC 1082 bool "Multi-core scheduler support" 1083 help 1084 Multi-core scheduler support improves the CPU scheduler's decision 1085 making when dealing with multi-core CPU chips at a cost of slightly 1086 increased overhead in some places. If unsure say N here. 1087 1088config SCHED_SMT 1089 bool "SMT scheduler support" 1090 help 1091 Improves the CPU scheduler's decision making when dealing with 1092 MultiThreading at a cost of slightly increased overhead in some 1093 places. If unsure say N here. 1094 1095config NR_CPUS 1096 int "Maximum number of CPUs (2-4096)" 1097 range 2 4096 1098 default "256" 1099 1100config HOTPLUG_CPU 1101 bool "Support for hot-pluggable CPUs" 1102 select GENERIC_IRQ_MIGRATION 1103 help 1104 Say Y here to experiment with turning CPUs off and on. CPUs 1105 can be controlled through /sys/devices/system/cpu. 1106 1107# Common NUMA Features 1108config NUMA 1109 bool "NUMA Memory Allocation and Scheduler Support" 1110 select ACPI_NUMA if ACPI 1111 select OF_NUMA 1112 help 1113 Enable NUMA (Non-Uniform Memory Access) support. 1114 1115 The kernel will try to allocate memory used by a CPU on the 1116 local memory of the CPU and add some more 1117 NUMA awareness to the kernel. 1118 1119config NODES_SHIFT 1120 int "Maximum NUMA Nodes (as a power of 2)" 1121 range 1 10 1122 default "4" 1123 depends on NEED_MULTIPLE_NODES 1124 help 1125 Specify the maximum number of NUMA Nodes available on the target 1126 system. Increases memory reserved to accommodate various tables. 1127 1128config USE_PERCPU_NUMA_NODE_ID 1129 def_bool y 1130 depends on NUMA 1131 1132config HAVE_SETUP_PER_CPU_AREA 1133 def_bool y 1134 depends on NUMA 1135 1136config NEED_PER_CPU_EMBED_FIRST_CHUNK 1137 def_bool y 1138 depends on NUMA 1139 1140config HOLES_IN_ZONE 1141 def_bool y 1142 1143source "kernel/Kconfig.hz" 1144 1145config ARCH_SUPPORTS_DEBUG_PAGEALLOC 1146 def_bool y 1147 1148config ARCH_SPARSEMEM_ENABLE 1149 def_bool y 1150 select SPARSEMEM_VMEMMAP_ENABLE 1151 1152config ARCH_SPARSEMEM_DEFAULT 1153 def_bool ARCH_SPARSEMEM_ENABLE 1154 1155config ARCH_SELECT_MEMORY_MODEL 1156 def_bool ARCH_SPARSEMEM_ENABLE 1157 1158config ARCH_FLATMEM_ENABLE 1159 def_bool !NUMA 1160 1161config HAVE_ARCH_PFN_VALID 1162 def_bool y 1163 1164config HW_PERF_EVENTS 1165 def_bool y 1166 depends on ARM_PMU 1167 1168config SYS_SUPPORTS_HUGETLBFS 1169 def_bool y 1170 1171config ARCH_WANT_HUGE_PMD_SHARE 1172 1173config ARCH_HAS_CACHE_LINE_SIZE 1174 def_bool y 1175 1176config ARCH_ENABLE_SPLIT_PMD_PTLOCK 1177 def_bool y if PGTABLE_LEVELS > 2 1178 1179# Supported by clang >= 7.0 1180config CC_HAVE_SHADOW_CALL_STACK 1181 def_bool $(cc-option, -fsanitize=shadow-call-stack -ffixed-x18) 1182 1183config PARAVIRT 1184 bool "Enable paravirtualization code" 1185 help 1186 This changes the kernel so it can modify itself when it is run 1187 under a hypervisor, potentially improving performance significantly 1188 over full virtualization. 1189 1190config PARAVIRT_TIME_ACCOUNTING 1191 bool "Paravirtual steal time accounting" 1192 select PARAVIRT 1193 help 1194 Select this option to enable fine granularity task steal time 1195 accounting. Time spent executing other tasks in parallel with 1196 the current vCPU is discounted from the vCPU power. To account for 1197 that, there can be a small performance impact. 1198 1199 If in doubt, say N here. 1200 1201config KEXEC 1202 depends on PM_SLEEP_SMP 1203 select KEXEC_CORE 1204 bool "kexec system call" 1205 help 1206 kexec is a system call that implements the ability to shutdown your 1207 current kernel, and to start another kernel. It is like a reboot 1208 but it is independent of the system firmware. And like a reboot 1209 you can start any kernel with it, not just Linux. 1210 1211config KEXEC_FILE 1212 bool "kexec file based system call" 1213 select KEXEC_CORE 1214 help 1215 This is new version of kexec system call. This system call is 1216 file based and takes file descriptors as system call argument 1217 for kernel and initramfs as opposed to list of segments as 1218 accepted by previous system call. 1219 1220config KEXEC_SIG 1221 bool "Verify kernel signature during kexec_file_load() syscall" 1222 depends on KEXEC_FILE 1223 help 1224 Select this option to verify a signature with loaded kernel 1225 image. If configured, any attempt of loading a image without 1226 valid signature will fail. 1227 1228 In addition to that option, you need to enable signature 1229 verification for the corresponding kernel image type being 1230 loaded in order for this to work. 1231 1232config KEXEC_IMAGE_VERIFY_SIG 1233 bool "Enable Image signature verification support" 1234 default y 1235 depends on KEXEC_SIG 1236 depends on EFI && SIGNED_PE_FILE_VERIFICATION 1237 help 1238 Enable Image signature verification support. 1239 1240comment "Support for PE file signature verification disabled" 1241 depends on KEXEC_SIG 1242 depends on !EFI || !SIGNED_PE_FILE_VERIFICATION 1243 1244config CRASH_DUMP 1245 bool "Build kdump crash kernel" 1246 help 1247 Generate crash dump after being started by kexec. This should 1248 be normally only set in special crash dump kernels which are 1249 loaded in the main kernel with kexec-tools into a specially 1250 reserved region and then later executed after a crash by 1251 kdump/kexec. 1252 1253 For more details see Documentation/admin-guide/kdump/kdump.rst 1254 1255config XEN_DOM0 1256 def_bool y 1257 depends on XEN 1258 1259config XEN 1260 bool "Xen guest support on ARM64" 1261 depends on ARM64 && OF 1262 select SWIOTLB_XEN 1263 select PARAVIRT 1264 help 1265 Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64. 1266 1267config FORCE_MAX_ZONEORDER 1268 int 1269 default "14" if (ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE) 1270 default "12" if (ARM64_16K_PAGES && TRANSPARENT_HUGEPAGE) 1271 default "11" 1272 help 1273 The kernel memory allocator divides physically contiguous memory 1274 blocks into "zones", where each zone is a power of two number of 1275 pages. This option selects the largest power of two that the kernel 1276 keeps in the memory allocator. If you need to allocate very large 1277 blocks of physically contiguous memory, then you may need to 1278 increase this value. 1279 1280 This config option is actually maximum order plus one. For example, 1281 a value of 11 means that the largest free memory block is 2^10 pages. 1282 1283 We make sure that we can allocate upto a HugePage size for each configuration. 1284 Hence we have : 1285 MAX_ORDER = (PMD_SHIFT - PAGE_SHIFT) + 1 => PAGE_SHIFT - 2 1286 1287 However for 4K, we choose a higher default value, 11 as opposed to 10, giving us 1288 4M allocations matching the default size used by generic code. 1289 1290config UNMAP_KERNEL_AT_EL0 1291 bool "Unmap kernel when running in userspace (aka \"KAISER\")" if EXPERT 1292 default y 1293 help 1294 Speculation attacks against some high-performance processors can 1295 be used to bypass MMU permission checks and leak kernel data to 1296 userspace. This can be defended against by unmapping the kernel 1297 when running in userspace, mapping it back in on exception entry 1298 via a trampoline page in the vector table. 1299 1300 If unsure, say Y. 1301 1302config MITIGATE_SPECTRE_BRANCH_HISTORY 1303 bool "Mitigate Spectre style attacks against branch history" if EXPERT 1304 default y 1305 help 1306 Speculation attacks against some high-performance processors can 1307 make use of branch history to influence future speculation. 1308 When taking an exception from user-space, a sequence of branches 1309 or a firmware call overwrites the branch history. 1310 1311config RODATA_FULL_DEFAULT_ENABLED 1312 bool "Apply r/o permissions of VM areas also to their linear aliases" 1313 default y 1314 help 1315 Apply read-only attributes of VM areas to the linear alias of 1316 the backing pages as well. This prevents code or read-only data 1317 from being modified (inadvertently or intentionally) via another 1318 mapping of the same memory page. This additional enhancement can 1319 be turned off at runtime by passing rodata=[off|on] (and turned on 1320 with rodata=full if this option is set to 'n') 1321 1322 This requires the linear region to be mapped down to pages, 1323 which may adversely affect performance in some cases. 1324 1325config ARM64_SW_TTBR0_PAN 1326 bool "Emulate Privileged Access Never using TTBR0_EL1 switching" 1327 help 1328 Enabling this option prevents the kernel from accessing 1329 user-space memory directly by pointing TTBR0_EL1 to a reserved 1330 zeroed area and reserved ASID. The user access routines 1331 restore the valid TTBR0_EL1 temporarily. 1332 1333config ARM64_TAGGED_ADDR_ABI 1334 bool "Enable the tagged user addresses syscall ABI" 1335 default y 1336 help 1337 When this option is enabled, user applications can opt in to a 1338 relaxed ABI via prctl() allowing tagged addresses to be passed 1339 to system calls as pointer arguments. For details, see 1340 Documentation/arm64/tagged-address-abi.rst. 1341 1342menuconfig COMPAT 1343 bool "Kernel support for 32-bit EL0" 1344 depends on ARM64_4K_PAGES || EXPERT 1345 select COMPAT_BINFMT_ELF if BINFMT_ELF 1346 select HAVE_UID16 1347 select OLD_SIGSUSPEND3 1348 select COMPAT_OLD_SIGACTION 1349 help 1350 This option enables support for a 32-bit EL0 running under a 64-bit 1351 kernel at EL1. AArch32-specific components such as system calls, 1352 the user helper functions, VFP support and the ptrace interface are 1353 handled appropriately by the kernel. 1354 1355 If you use a page size other than 4KB (i.e, 16KB or 64KB), please be aware 1356 that you will only be able to execute AArch32 binaries that were compiled 1357 with page size aligned segments. 1358 1359 If you want to execute 32-bit userspace applications, say Y. 1360 1361if COMPAT 1362 1363config KUSER_HELPERS 1364 bool "Enable kuser helpers page for 32-bit applications" 1365 default y 1366 help 1367 Warning: disabling this option may break 32-bit user programs. 1368 1369 Provide kuser helpers to compat tasks. The kernel provides 1370 helper code to userspace in read only form at a fixed location 1371 to allow userspace to be independent of the CPU type fitted to 1372 the system. This permits binaries to be run on ARMv4 through 1373 to ARMv8 without modification. 1374 1375 See Documentation/arm/kernel_user_helpers.rst for details. 1376 1377 However, the fixed address nature of these helpers can be used 1378 by ROP (return orientated programming) authors when creating 1379 exploits. 1380 1381 If all of the binaries and libraries which run on your platform 1382 are built specifically for your platform, and make no use of 1383 these helpers, then you can turn this option off to hinder 1384 such exploits. However, in that case, if a binary or library 1385 relying on those helpers is run, it will not function correctly. 1386 1387 Say N here only if you are absolutely certain that you do not 1388 need these helpers; otherwise, the safe option is to say Y. 1389 1390config COMPAT_VDSO 1391 bool "Enable vDSO for 32-bit applications" 1392 depends on !CPU_BIG_ENDIAN 1393 depends on (CC_IS_CLANG && LD_IS_LLD) || "$(CROSS_COMPILE_COMPAT)" != "" 1394 select GENERIC_COMPAT_VDSO 1395 default y 1396 help 1397 Place in the process address space of 32-bit applications an 1398 ELF shared object providing fast implementations of gettimeofday 1399 and clock_gettime. 1400 1401 You must have a 32-bit build of glibc 2.22 or later for programs 1402 to seamlessly take advantage of this. 1403 1404config THUMB2_COMPAT_VDSO 1405 bool "Compile the 32-bit vDSO for Thumb-2 mode" if EXPERT 1406 depends on COMPAT_VDSO 1407 default y 1408 help 1409 Compile the compat vDSO with '-mthumb -fomit-frame-pointer' if y, 1410 otherwise with '-marm'. 1411 1412menuconfig ARMV8_DEPRECATED 1413 bool "Emulate deprecated/obsolete ARMv8 instructions" 1414 depends on SYSCTL 1415 help 1416 Legacy software support may require certain instructions 1417 that have been deprecated or obsoleted in the architecture. 1418 1419 Enable this config to enable selective emulation of these 1420 features. 1421 1422 If unsure, say Y 1423 1424if ARMV8_DEPRECATED 1425 1426config SWP_EMULATION 1427 bool "Emulate SWP/SWPB instructions" 1428 help 1429 ARMv8 obsoletes the use of A32 SWP/SWPB instructions such that 1430 they are always undefined. Say Y here to enable software 1431 emulation of these instructions for userspace using LDXR/STXR. 1432 This feature can be controlled at runtime with the abi.swp 1433 sysctl which is disabled by default. 1434 1435 In some older versions of glibc [<=2.8] SWP is used during futex 1436 trylock() operations with the assumption that the code will not 1437 be preempted. This invalid assumption may be more likely to fail 1438 with SWP emulation enabled, leading to deadlock of the user 1439 application. 1440 1441 NOTE: when accessing uncached shared regions, LDXR/STXR rely 1442 on an external transaction monitoring block called a global 1443 monitor to maintain update atomicity. If your system does not 1444 implement a global monitor, this option can cause programs that 1445 perform SWP operations to uncached memory to deadlock. 1446 1447 If unsure, say Y 1448 1449config CP15_BARRIER_EMULATION 1450 bool "Emulate CP15 Barrier instructions" 1451 help 1452 The CP15 barrier instructions - CP15ISB, CP15DSB, and 1453 CP15DMB - are deprecated in ARMv8 (and ARMv7). It is 1454 strongly recommended to use the ISB, DSB, and DMB 1455 instructions instead. 1456 1457 Say Y here to enable software emulation of these 1458 instructions for AArch32 userspace code. When this option is 1459 enabled, CP15 barrier usage is traced which can help 1460 identify software that needs updating. This feature can be 1461 controlled at runtime with the abi.cp15_barrier sysctl. 1462 1463 If unsure, say Y 1464 1465config SETEND_EMULATION 1466 bool "Emulate SETEND instruction" 1467 help 1468 The SETEND instruction alters the data-endianness of the 1469 AArch32 EL0, and is deprecated in ARMv8. 1470 1471 Say Y here to enable software emulation of the instruction 1472 for AArch32 userspace code. This feature can be controlled 1473 at runtime with the abi.setend sysctl. 1474 1475 Note: All the cpus on the system must have mixed endian support at EL0 1476 for this feature to be enabled. If a new CPU - which doesn't support mixed 1477 endian - is hotplugged in after this feature has been enabled, there could 1478 be unexpected results in the applications. 1479 1480 If unsure, say Y 1481endif 1482 1483endif 1484 1485menu "ARMv8.1 architectural features" 1486 1487config ARM64_HW_AFDBM 1488 bool "Support for hardware updates of the Access and Dirty page flags" 1489 default y 1490 help 1491 The ARMv8.1 architecture extensions introduce support for 1492 hardware updates of the access and dirty information in page 1493 table entries. When enabled in TCR_EL1 (HA and HD bits) on 1494 capable processors, accesses to pages with PTE_AF cleared will 1495 set this bit instead of raising an access flag fault. 1496 Similarly, writes to read-only pages with the DBM bit set will 1497 clear the read-only bit (AP[2]) instead of raising a 1498 permission fault. 1499 1500 Kernels built with this configuration option enabled continue 1501 to work on pre-ARMv8.1 hardware and the performance impact is 1502 minimal. If unsure, say Y. 1503 1504config ARM64_PAN 1505 bool "Enable support for Privileged Access Never (PAN)" 1506 default y 1507 help 1508 Privileged Access Never (PAN; part of the ARMv8.1 Extensions) 1509 prevents the kernel or hypervisor from accessing user-space (EL0) 1510 memory directly. 1511 1512 Choosing this option will cause any unprotected (not using 1513 copy_to_user et al) memory access to fail with a permission fault. 1514 1515 The feature is detected at runtime, and will remain as a 'nop' 1516 instruction if the cpu does not implement the feature. 1517 1518config AS_HAS_LDAPR 1519 def_bool $(as-instr,.arch_extension rcpc) 1520 1521config AS_HAS_LSE_ATOMICS 1522 def_bool $(as-instr,.arch_extension lse) 1523 1524config ARM64_LSE_ATOMICS 1525 bool 1526 default ARM64_USE_LSE_ATOMICS 1527 depends on AS_HAS_LSE_ATOMICS 1528 1529config ARM64_USE_LSE_ATOMICS 1530 bool "Atomic instructions" 1531 depends on JUMP_LABEL 1532 default y 1533 help 1534 As part of the Large System Extensions, ARMv8.1 introduces new 1535 atomic instructions that are designed specifically to scale in 1536 very large systems. 1537 1538 Say Y here to make use of these instructions for the in-kernel 1539 atomic routines. This incurs a small overhead on CPUs that do 1540 not support these instructions and requires the kernel to be 1541 built with binutils >= 2.25 in order for the new instructions 1542 to be used. 1543 1544config ARM64_VHE 1545 bool "Enable support for Virtualization Host Extensions (VHE)" 1546 default y 1547 help 1548 Virtualization Host Extensions (VHE) allow the kernel to run 1549 directly at EL2 (instead of EL1) on processors that support 1550 it. This leads to better performance for KVM, as they reduce 1551 the cost of the world switch. 1552 1553 Selecting this option allows the VHE feature to be detected 1554 at runtime, and does not affect processors that do not 1555 implement this feature. 1556 1557endmenu 1558 1559menu "ARMv8.2 architectural features" 1560 1561config ARM64_UAO 1562 bool "Enable support for User Access Override (UAO)" 1563 default y 1564 help 1565 User Access Override (UAO; part of the ARMv8.2 Extensions) 1566 causes the 'unprivileged' variant of the load/store instructions to 1567 be overridden to be privileged. 1568 1569 This option changes get_user() and friends to use the 'unprivileged' 1570 variant of the load/store instructions. This ensures that user-space 1571 really did have access to the supplied memory. When addr_limit is 1572 set to kernel memory the UAO bit will be set, allowing privileged 1573 access to kernel memory. 1574 1575 Choosing this option will cause copy_to_user() et al to use user-space 1576 memory permissions. 1577 1578 The feature is detected at runtime, the kernel will use the 1579 regular load/store instructions if the cpu does not implement the 1580 feature. 1581 1582config ARM64_PMEM 1583 bool "Enable support for persistent memory" 1584 select ARCH_HAS_PMEM_API 1585 select ARCH_HAS_UACCESS_FLUSHCACHE 1586 help 1587 Say Y to enable support for the persistent memory API based on the 1588 ARMv8.2 DCPoP feature. 1589 1590 The feature is detected at runtime, and the kernel will use DC CVAC 1591 operations if DC CVAP is not supported (following the behaviour of 1592 DC CVAP itself if the system does not define a point of persistence). 1593 1594config ARM64_RAS_EXTN 1595 bool "Enable support for RAS CPU Extensions" 1596 default y 1597 help 1598 CPUs that support the Reliability, Availability and Serviceability 1599 (RAS) Extensions, part of ARMv8.2 are able to track faults and 1600 errors, classify them and report them to software. 1601 1602 On CPUs with these extensions system software can use additional 1603 barriers to determine if faults are pending and read the 1604 classification from a new set of registers. 1605 1606 Selecting this feature will allow the kernel to use these barriers 1607 and access the new registers if the system supports the extension. 1608 Platform RAS features may additionally depend on firmware support. 1609 1610config ARM64_CNP 1611 bool "Enable support for Common Not Private (CNP) translations" 1612 default y 1613 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN 1614 help 1615 Common Not Private (CNP) allows translation table entries to 1616 be shared between different PEs in the same inner shareable 1617 domain, so the hardware can use this fact to optimise the 1618 caching of such entries in the TLB. 1619 1620 Selecting this option allows the CNP feature to be detected 1621 at runtime, and does not affect PEs that do not implement 1622 this feature. 1623 1624endmenu 1625 1626menu "ARMv8.3 architectural features" 1627 1628config ARM64_PTR_AUTH 1629 bool "Enable support for pointer authentication" 1630 default y 1631 depends on (CC_HAS_SIGN_RETURN_ADDRESS || CC_HAS_BRANCH_PROT_PAC_RET) && AS_HAS_PAC 1632 # Modern compilers insert a .note.gnu.property section note for PAC 1633 # which is only understood by binutils starting with version 2.33.1. 1634 depends on LD_IS_LLD || LD_VERSION >= 233010000 || (CC_IS_GCC && GCC_VERSION < 90100) 1635 depends on !CC_IS_CLANG || AS_HAS_CFI_NEGATE_RA_STATE 1636 depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_REGS) 1637 help 1638 Pointer authentication (part of the ARMv8.3 Extensions) provides 1639 instructions for signing and authenticating pointers against secret 1640 keys, which can be used to mitigate Return Oriented Programming (ROP) 1641 and other attacks. 1642 1643 This option enables these instructions at EL0 (i.e. for userspace). 1644 Choosing this option will cause the kernel to initialise secret keys 1645 for each process at exec() time, with these keys being 1646 context-switched along with the process. 1647 1648 If the compiler supports the -mbranch-protection or 1649 -msign-return-address flag (e.g. GCC 7 or later), then this option 1650 will also cause the kernel itself to be compiled with return address 1651 protection. In this case, and if the target hardware is known to 1652 support pointer authentication, then CONFIG_STACKPROTECTOR can be 1653 disabled with minimal loss of protection. 1654 1655 The feature is detected at runtime. If the feature is not present in 1656 hardware it will not be advertised to userspace/KVM guest nor will it 1657 be enabled. 1658 1659 If the feature is present on the boot CPU but not on a late CPU, then 1660 the late CPU will be parked. Also, if the boot CPU does not have 1661 address auth and the late CPU has then the late CPU will still boot 1662 but with the feature disabled. On such a system, this option should 1663 not be selected. 1664 1665 This feature works with FUNCTION_GRAPH_TRACER option only if 1666 DYNAMIC_FTRACE_WITH_REGS is enabled. 1667 1668config CC_HAS_BRANCH_PROT_PAC_RET 1669 # GCC 9 or later, clang 8 or later 1670 def_bool $(cc-option,-mbranch-protection=pac-ret+leaf) 1671 1672config CC_HAS_SIGN_RETURN_ADDRESS 1673 # GCC 7, 8 1674 def_bool $(cc-option,-msign-return-address=all) 1675 1676config AS_HAS_PAC 1677 def_bool $(cc-option,-Wa$(comma)-march=armv8.3-a) 1678 1679config AS_HAS_CFI_NEGATE_RA_STATE 1680 def_bool $(as-instr,.cfi_startproc\n.cfi_negate_ra_state\n.cfi_endproc\n) 1681 1682endmenu 1683 1684menu "ARMv8.4 architectural features" 1685 1686config ARM64_AMU_EXTN 1687 bool "Enable support for the Activity Monitors Unit CPU extension" 1688 default y 1689 help 1690 The activity monitors extension is an optional extension introduced 1691 by the ARMv8.4 CPU architecture. This enables support for version 1 1692 of the activity monitors architecture, AMUv1. 1693 1694 To enable the use of this extension on CPUs that implement it, say Y. 1695 1696 Note that for architectural reasons, firmware _must_ implement AMU 1697 support when running on CPUs that present the activity monitors 1698 extension. The required support is present in: 1699 * Version 1.5 and later of the ARM Trusted Firmware 1700 1701 For kernels that have this configuration enabled but boot with broken 1702 firmware, you may need to say N here until the firmware is fixed. 1703 Otherwise you may experience firmware panics or lockups when 1704 accessing the counter registers. Even if you are not observing these 1705 symptoms, the values returned by the register reads might not 1706 correctly reflect reality. Most commonly, the value read will be 0, 1707 indicating that the counter is not enabled. 1708 1709config AS_HAS_ARMV8_4 1710 def_bool $(cc-option,-Wa$(comma)-march=armv8.4-a) 1711 1712config ARM64_TLB_RANGE 1713 bool "Enable support for tlbi range feature" 1714 default y 1715 depends on AS_HAS_ARMV8_4 1716 help 1717 ARMv8.4-TLBI provides TLBI invalidation instruction that apply to a 1718 range of input addresses. 1719 1720 The feature introduces new assembly instructions, and they were 1721 support when binutils >= 2.30. 1722 1723endmenu 1724 1725menu "ARMv8.5 architectural features" 1726 1727config AS_HAS_ARMV8_5 1728 def_bool $(cc-option,-Wa$(comma)-march=armv8.5-a) 1729 1730config ARM64_BTI 1731 bool "Branch Target Identification support" 1732 default y 1733 help 1734 Branch Target Identification (part of the ARMv8.5 Extensions) 1735 provides a mechanism to limit the set of locations to which computed 1736 branch instructions such as BR or BLR can jump. 1737 1738 To make use of BTI on CPUs that support it, say Y. 1739 1740 BTI is intended to provide complementary protection to other control 1741 flow integrity protection mechanisms, such as the Pointer 1742 authentication mechanism provided as part of the ARMv8.3 Extensions. 1743 For this reason, it does not make sense to enable this option without 1744 also enabling support for pointer authentication. Thus, when 1745 enabling this option you should also select ARM64_PTR_AUTH=y. 1746 1747 Userspace binaries must also be specifically compiled to make use of 1748 this mechanism. If you say N here or the hardware does not support 1749 BTI, such binaries can still run, but you get no additional 1750 enforcement of branch destinations. 1751 1752config ARM64_BTI_KERNEL 1753 bool "Use Branch Target Identification for kernel" 1754 default y 1755 depends on ARM64_BTI 1756 depends on ARM64_PTR_AUTH 1757 depends on CC_HAS_BRANCH_PROT_PAC_RET_BTI 1758 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94697 1759 depends on !CC_IS_GCC || GCC_VERSION >= 100100 1760 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106671 1761 depends on !CC_IS_GCC 1762 # https://bugs.llvm.org/show_bug.cgi?id=46258 1763 depends on !CFI_CLANG || CLANG_VERSION >= 120000 1764 depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_REGS) 1765 help 1766 Build the kernel with Branch Target Identification annotations 1767 and enable enforcement of this for kernel code. When this option 1768 is enabled and the system supports BTI all kernel code including 1769 modular code must have BTI enabled. 1770 1771config CC_HAS_BRANCH_PROT_PAC_RET_BTI 1772 # GCC 9 or later, clang 8 or later 1773 def_bool $(cc-option,-mbranch-protection=pac-ret+leaf+bti) 1774 1775config ARM64_E0PD 1776 bool "Enable support for E0PD" 1777 default y 1778 help 1779 E0PD (part of the ARMv8.5 extensions) allows us to ensure 1780 that EL0 accesses made via TTBR1 always fault in constant time, 1781 providing similar benefits to KASLR as those provided by KPTI, but 1782 with lower overhead and without disrupting legitimate access to 1783 kernel memory such as SPE. 1784 1785 This option enables E0PD for TTBR1 where available. 1786 1787config ARCH_RANDOM 1788 bool "Enable support for random number generation" 1789 default y 1790 help 1791 Random number generation (part of the ARMv8.5 Extensions) 1792 provides a high bandwidth, cryptographically secure 1793 hardware random number generator. 1794 1795config ARM64_AS_HAS_MTE 1796 # Initial support for MTE went in binutils 2.32.0, checked with 1797 # ".arch armv8.5-a+memtag" below. However, this was incomplete 1798 # as a late addition to the final architecture spec (LDGM/STGM) 1799 # is only supported in the newer 2.32.x and 2.33 binutils 1800 # versions, hence the extra "stgm" instruction check below. 1801 def_bool $(as-instr,.arch armv8.5-a+memtag\nstgm xzr$(comma)[x0]) 1802 1803config ARM64_MTE 1804 bool "Memory Tagging Extension support" 1805 default y 1806 depends on ARM64_AS_HAS_MTE && ARM64_TAGGED_ADDR_ABI 1807 depends on AS_HAS_ARMV8_5 1808 # Required for tag checking in the uaccess routines 1809 depends on ARM64_PAN 1810 depends on AS_HAS_LSE_ATOMICS 1811 select ARCH_USES_HIGH_VMA_FLAGS 1812 help 1813 Memory Tagging (part of the ARMv8.5 Extensions) provides 1814 architectural support for run-time, always-on detection of 1815 various classes of memory error to aid with software debugging 1816 to eliminate vulnerabilities arising from memory-unsafe 1817 languages. 1818 1819 This option enables the support for the Memory Tagging 1820 Extension at EL0 (i.e. for userspace). 1821 1822 Selecting this option allows the feature to be detected at 1823 runtime. Any secondary CPU not implementing this feature will 1824 not be allowed a late bring-up. 1825 1826 Userspace binaries that want to use this feature must 1827 explicitly opt in. The mechanism for the userspace is 1828 described in: 1829 1830 Documentation/arm64/memory-tagging-extension.rst. 1831 1832endmenu 1833 1834config ARM64_SVE 1835 bool "ARM Scalable Vector Extension support" 1836 default y 1837 help 1838 The Scalable Vector Extension (SVE) is an extension to the AArch64 1839 execution state which complements and extends the SIMD functionality 1840 of the base architecture to support much larger vectors and to enable 1841 additional vectorisation opportunities. 1842 1843 To enable use of this extension on CPUs that implement it, say Y. 1844 1845 On CPUs that support the SVE2 extensions, this option will enable 1846 those too. 1847 1848 Note that for architectural reasons, firmware _must_ implement SVE 1849 support when running on SVE capable hardware. The required support 1850 is present in: 1851 1852 * version 1.5 and later of the ARM Trusted Firmware 1853 * the AArch64 boot wrapper since commit 5e1261e08abf 1854 ("bootwrapper: SVE: Enable SVE for EL2 and below"). 1855 1856 For other firmware implementations, consult the firmware documentation 1857 or vendor. 1858 1859 If you need the kernel to boot on SVE-capable hardware with broken 1860 firmware, you may need to say N here until you get your firmware 1861 fixed. Otherwise, you may experience firmware panics or lockups when 1862 booting the kernel. If unsure and you are not observing these 1863 symptoms, you should assume that it is safe to say Y. 1864 1865config ARM64_MODULE_PLTS 1866 bool "Use PLTs to allow module memory to spill over into vmalloc area" 1867 depends on MODULES 1868 select HAVE_MOD_ARCH_SPECIFIC 1869 help 1870 Allocate PLTs when loading modules so that jumps and calls whose 1871 targets are too far away for their relative offsets to be encoded 1872 in the instructions themselves can be bounced via veneers in the 1873 module's PLT. This allows modules to be allocated in the generic 1874 vmalloc area after the dedicated module memory area has been 1875 exhausted. 1876 1877 When running with address space randomization (KASLR), the module 1878 region itself may be too far away for ordinary relative jumps and 1879 calls, and so in that case, module PLTs are required and cannot be 1880 disabled. 1881 1882 Specific errata workaround(s) might also force module PLTs to be 1883 enabled (ARM64_ERRATUM_843419). 1884 1885config ARM64_PSEUDO_NMI 1886 bool "Support for NMI-like interrupts" 1887 select ARM_GIC_V3 1888 help 1889 Adds support for mimicking Non-Maskable Interrupts through the use of 1890 GIC interrupt priority. This support requires version 3 or later of 1891 ARM GIC. 1892 1893 This high priority configuration for interrupts needs to be 1894 explicitly enabled by setting the kernel parameter 1895 "irqchip.gicv3_pseudo_nmi" to 1. 1896 1897 If unsure, say N 1898 1899if ARM64_PSEUDO_NMI 1900config ARM64_DEBUG_PRIORITY_MASKING 1901 bool "Debug interrupt priority masking" 1902 help 1903 This adds runtime checks to functions enabling/disabling 1904 interrupts when using priority masking. The additional checks verify 1905 the validity of ICC_PMR_EL1 when calling concerned functions. 1906 1907 If unsure, say N 1908endif 1909 1910config RELOCATABLE 1911 bool "Build a relocatable kernel image" if EXPERT 1912 select ARCH_HAS_RELR 1913 default y 1914 help 1915 This builds the kernel as a Position Independent Executable (PIE), 1916 which retains all relocation metadata required to relocate the 1917 kernel binary at runtime to a different virtual address than the 1918 address it was linked at. 1919 Since AArch64 uses the RELA relocation format, this requires a 1920 relocation pass at runtime even if the kernel is loaded at the 1921 same address it was linked at. 1922 1923config RANDOMIZE_BASE 1924 bool "Randomize the address of the kernel image" 1925 select ARM64_MODULE_PLTS if MODULES 1926 select RELOCATABLE 1927 help 1928 Randomizes the virtual address at which the kernel image is 1929 loaded, as a security feature that deters exploit attempts 1930 relying on knowledge of the location of kernel internals. 1931 1932 It is the bootloader's job to provide entropy, by passing a 1933 random u64 value in /chosen/kaslr-seed at kernel entry. 1934 1935 When booting via the UEFI stub, it will invoke the firmware's 1936 EFI_RNG_PROTOCOL implementation (if available) to supply entropy 1937 to the kernel proper. In addition, it will randomise the physical 1938 location of the kernel Image as well. 1939 1940 If unsure, say N. 1941 1942config RANDOMIZE_MODULE_REGION_FULL 1943 bool "Randomize the module region over a 4 GB range" 1944 depends on RANDOMIZE_BASE 1945 default y 1946 help 1947 Randomizes the location of the module region inside a 4 GB window 1948 covering the core kernel. This way, it is less likely for modules 1949 to leak information about the location of core kernel data structures 1950 but it does imply that function calls between modules and the core 1951 kernel will need to be resolved via veneers in the module PLT. 1952 1953 When this option is not set, the module region will be randomized over 1954 a limited range that contains the [_stext, _etext] interval of the 1955 core kernel, so branch relocations are always in range. 1956 1957config CC_HAVE_STACKPROTECTOR_SYSREG 1958 def_bool $(cc-option,-mstack-protector-guard=sysreg -mstack-protector-guard-reg=sp_el0 -mstack-protector-guard-offset=0) 1959 1960config STACKPROTECTOR_PER_TASK 1961 def_bool y 1962 depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_SYSREG 1963 1964endmenu 1965 1966menu "Boot options" 1967 1968config ARM64_ACPI_PARKING_PROTOCOL 1969 bool "Enable support for the ARM64 ACPI parking protocol" 1970 depends on ACPI 1971 help 1972 Enable support for the ARM64 ACPI parking protocol. If disabled 1973 the kernel will not allow booting through the ARM64 ACPI parking 1974 protocol even if the corresponding data is present in the ACPI 1975 MADT table. 1976 1977config CMDLINE 1978 string "Default kernel command string" 1979 default "" 1980 help 1981 Provide a set of default command-line options at build time by 1982 entering them here. As a minimum, you should specify the the 1983 root device (e.g. root=/dev/nfs). 1984 1985choice 1986 prompt "Kernel command line type" if CMDLINE != "" 1987 default CMDLINE_FROM_BOOTLOADER 1988 help 1989 Choose how the kernel will handle the provided default kernel 1990 command line string. 1991 1992config CMDLINE_FROM_BOOTLOADER 1993 bool "Use bootloader kernel arguments if available" 1994 help 1995 Uses the command-line options passed by the boot loader. If 1996 the boot loader doesn't provide any, the default kernel command 1997 string provided in CMDLINE will be used. 1998 1999config CMDLINE_EXTEND 2000 bool "Extend bootloader kernel arguments" 2001 help 2002 The command-line arguments provided by the boot loader will be 2003 appended to the default kernel command string. 2004 2005config CMDLINE_FORCE 2006 bool "Always use the default kernel command string" 2007 help 2008 Always use the default kernel command string, even if the boot 2009 loader passes other arguments to the kernel. 2010 This is useful if you cannot or don't want to change the 2011 command-line options your boot loader passes to the kernel. 2012 2013endchoice 2014 2015config EFI_STUB 2016 bool 2017 2018config EFI 2019 bool "UEFI runtime support" 2020 depends on OF && !CPU_BIG_ENDIAN 2021 depends on KERNEL_MODE_NEON 2022 select ARCH_SUPPORTS_ACPI 2023 select LIBFDT 2024 select UCS2_STRING 2025 select EFI_PARAMS_FROM_FDT 2026 select EFI_RUNTIME_WRAPPERS 2027 select EFI_STUB 2028 select EFI_GENERIC_STUB 2029 default y 2030 help 2031 This option provides support for runtime services provided 2032 by UEFI firmware (such as non-volatile variables, realtime 2033 clock, and platform reset). A UEFI stub is also provided to 2034 allow the kernel to be booted as an EFI application. This 2035 is only useful on systems that have UEFI firmware. 2036 2037config DMI 2038 bool "Enable support for SMBIOS (DMI) tables" 2039 depends on EFI 2040 default y 2041 help 2042 This enables SMBIOS/DMI feature for systems. 2043 2044 This option is only useful on systems that have UEFI firmware. 2045 However, even with this option, the resultant kernel should 2046 continue to boot on existing non-UEFI platforms. 2047 2048endmenu 2049 2050config SYSVIPC_COMPAT 2051 def_bool y 2052 depends on COMPAT && SYSVIPC 2053 2054config ARCH_ENABLE_HUGEPAGE_MIGRATION 2055 def_bool y 2056 depends on HUGETLB_PAGE && MIGRATION 2057 2058config ARCH_ENABLE_THP_MIGRATION 2059 def_bool y 2060 depends on TRANSPARENT_HUGEPAGE 2061 2062menu "Power management options" 2063 2064source "kernel/power/Kconfig" 2065 2066config ARCH_HIBERNATION_POSSIBLE 2067 def_bool y 2068 depends on CPU_PM 2069 2070config ARCH_HIBERNATION_HEADER 2071 def_bool y 2072 depends on HIBERNATION 2073 2074config ARCH_SUSPEND_POSSIBLE 2075 def_bool y 2076 2077endmenu 2078 2079menu "CPU Power Management" 2080 2081source "drivers/cpuidle/Kconfig" 2082 2083source "drivers/cpufreq/Kconfig" 2084 2085endmenu 2086 2087source "drivers/firmware/Kconfig" 2088 2089source "drivers/acpi/Kconfig" 2090 2091source "arch/arm64/kvm/Kconfig" 2092 2093if CRYPTO 2094source "arch/arm64/crypto/Kconfig" 2095endif 2096