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_CFI_CLANG 79 select ARCH_SUPPORTS_ATOMIC_RMW 80 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && (GCC_VERSION >= 50000 || CC_IS_CLANG) 81 select ARCH_SUPPORTS_NUMA_BALANCING 82 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT 83 select ARCH_WANT_DEFAULT_BPF_JIT 84 select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT 85 select ARCH_WANT_FRAME_POINTERS 86 select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36) 87 select ARCH_WANT_LD_ORPHAN_WARN 88 select ARCH_HAS_UBSAN_SANITIZE_ALL 89 select ARM_AMBA 90 select ARM_ARCH_TIMER 91 select ARM_GIC 92 select AUDIT_ARCH_COMPAT_GENERIC 93 select ARM_GIC_V2M if PCI 94 select ARM_GIC_V3 95 select ARM_GIC_V3_ITS if PCI 96 select ARM_PSCI_FW 97 select BUILDTIME_TABLE_SORT 98 select CLONE_BACKWARDS 99 select COMMON_CLK 100 select CPU_PM if (SUSPEND || CPU_IDLE) 101 select CRC32 102 select DCACHE_WORD_ACCESS 103 select DMA_DIRECT_REMAP 104 select EDAC_SUPPORT 105 select FRAME_POINTER 106 select GENERIC_ALLOCATOR 107 select GENERIC_ARCH_TOPOLOGY 108 select GENERIC_CLOCKEVENTS 109 select GENERIC_CLOCKEVENTS_BROADCAST 110 select GENERIC_CPU_AUTOPROBE 111 select GENERIC_CPU_VULNERABILITIES 112 select GENERIC_EARLY_IOREMAP 113 select GENERIC_IDLE_POLL_SETUP 114 select GENERIC_IRQ_IPI 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_PCI 132 select HAVE_ACPI_APEI if (ACPI && EFI) 133 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 134 select HAVE_ARCH_AUDITSYSCALL 135 select HAVE_ARCH_BITREVERSE 136 select HAVE_ARCH_COMPILER_H 137 select HAVE_ARCH_HUGE_VMAP 138 select HAVE_ARCH_JUMP_LABEL 139 select HAVE_ARCH_JUMP_LABEL_RELATIVE 140 select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48) 141 select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN 142 select HAVE_ARCH_KGDB 143 select HAVE_ARCH_MMAP_RND_BITS 144 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT 145 select HAVE_ARCH_PREL32_RELOCATIONS 146 select HAVE_ARCH_SECCOMP_FILTER 147 select HAVE_ARCH_STACKLEAK 148 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 149 select HAVE_ARCH_TRACEHOOK 150 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 151 select HAVE_ARCH_VMAP_STACK 152 select HAVE_ARM_SMCCC 153 select HAVE_ASM_MODVERSIONS 154 select HAVE_EBPF_JIT 155 select HAVE_C_RECORDMCOUNT 156 select HAVE_CMPXCHG_DOUBLE 157 select HAVE_CMPXCHG_LOCAL 158 select HAVE_CONTEXT_TRACKING 159 select HAVE_DEBUG_BUGVERBOSE 160 select HAVE_DEBUG_KMEMLEAK 161 select HAVE_DMA_CONTIGUOUS 162 select HAVE_DYNAMIC_FTRACE 163 select HAVE_DYNAMIC_FTRACE_WITH_REGS \ 164 if $(cc-option,-fpatchable-function-entry=2) 165 select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY \ 166 if DYNAMIC_FTRACE_WITH_REGS 167 select HAVE_EFFICIENT_UNALIGNED_ACCESS 168 select HAVE_FAST_GUP 169 select HAVE_FTRACE_MCOUNT_RECORD 170 select HAVE_FUNCTION_TRACER 171 select HAVE_FUNCTION_ERROR_INJECTION 172 select HAVE_FUNCTION_GRAPH_TRACER 173 select HAVE_GCC_PLUGINS 174 select HAVE_HW_BREAKPOINT if PERF_EVENTS 175 select HAVE_IRQ_TIME_ACCOUNTING 176 select HAVE_NMI 177 select HAVE_PATA_PLATFORM 178 select HAVE_PERF_EVENTS 179 select HAVE_PERF_REGS 180 select HAVE_PERF_USER_STACK_DUMP 181 select HAVE_REGS_AND_STACK_ACCESS_API 182 select HAVE_FUNCTION_ARG_ACCESS_API 183 select HAVE_FUTEX_CMPXCHG if FUTEX 184 select MMU_GATHER_RCU_TABLE_FREE 185 select HAVE_RSEQ 186 select HAVE_STACKPROTECTOR 187 select HAVE_SYSCALL_TRACEPOINTS 188 select HAVE_KPROBES 189 select HAVE_KRETPROBES 190 select HAVE_GENERIC_VDSO 191 select HOLES_IN_ZONE 192 select IOMMU_DMA if IOMMU_SUPPORT 193 select IRQ_DOMAIN 194 select IRQ_FORCED_THREADING 195 select MODULES_USE_ELF_RELA 196 select NEED_DMA_MAP_STATE 197 select NEED_SG_DMA_LENGTH 198 select OF 199 select OF_EARLY_FLATTREE 200 select PCI_DOMAINS_GENERIC if PCI 201 select PCI_ECAM if (ACPI && PCI) 202 select PCI_SYSCALL if PCI 203 select POWER_RESET 204 select POWER_SUPPLY 205 select SET_FS 206 select SPARSE_IRQ 207 select SWIOTLB 208 select SYSCTL_EXCEPTION_TRACE 209 select THREAD_INFO_IN_TASK 210 help 211 ARM 64-bit (AArch64) Linux support. 212 213config 64BIT 214 def_bool y 215 216config MMU 217 def_bool y 218 219config ARM64_PAGE_SHIFT 220 int 221 default 16 if ARM64_64K_PAGES 222 default 14 if ARM64_16K_PAGES 223 default 12 224 225config ARM64_CONT_PTE_SHIFT 226 int 227 default 5 if ARM64_64K_PAGES 228 default 7 if ARM64_16K_PAGES 229 default 4 230 231config ARM64_CONT_PMD_SHIFT 232 int 233 default 5 if ARM64_64K_PAGES 234 default 5 if ARM64_16K_PAGES 235 default 4 236 237config ARCH_MMAP_RND_BITS_MIN 238 default 14 if ARM64_64K_PAGES 239 default 16 if ARM64_16K_PAGES 240 default 18 241 242# max bits determined by the following formula: 243# VA_BITS - PAGE_SHIFT - 3 244config ARCH_MMAP_RND_BITS_MAX 245 default 19 if ARM64_VA_BITS=36 246 default 24 if ARM64_VA_BITS=39 247 default 27 if ARM64_VA_BITS=42 248 default 30 if ARM64_VA_BITS=47 249 default 29 if ARM64_VA_BITS=48 && ARM64_64K_PAGES 250 default 31 if ARM64_VA_BITS=48 && ARM64_16K_PAGES 251 default 33 if ARM64_VA_BITS=48 252 default 14 if ARM64_64K_PAGES 253 default 16 if ARM64_16K_PAGES 254 default 18 255 256config ARCH_MMAP_RND_COMPAT_BITS_MIN 257 default 7 if ARM64_64K_PAGES 258 default 9 if ARM64_16K_PAGES 259 default 11 260 261config ARCH_MMAP_RND_COMPAT_BITS_MAX 262 default 16 263 264config NO_IOPORT_MAP 265 def_bool y if !PCI 266 267config STACKTRACE_SUPPORT 268 def_bool y 269 270config ILLEGAL_POINTER_VALUE 271 hex 272 default 0xdead000000000000 273 274config LOCKDEP_SUPPORT 275 def_bool y 276 277config TRACE_IRQFLAGS_SUPPORT 278 def_bool y 279 280config GENERIC_BUG 281 def_bool y 282 depends on BUG 283 284config GENERIC_BUG_RELATIVE_POINTERS 285 def_bool y 286 depends on GENERIC_BUG 287 288config GENERIC_HWEIGHT 289 def_bool y 290 291config GENERIC_CSUM 292 def_bool y 293 294config GENERIC_CALIBRATE_DELAY 295 def_bool y 296 297config ZONE_DMA 298 bool "Support DMA zone" if EXPERT 299 default y 300 301config ZONE_DMA32 302 bool "Support DMA32 zone" if EXPERT 303 default y 304 305config ARCH_ENABLE_MEMORY_HOTPLUG 306 def_bool y 307 308config ARCH_ENABLE_MEMORY_HOTREMOVE 309 def_bool y 310 311config SMP 312 def_bool y 313 314config KERNEL_MODE_NEON 315 def_bool y 316 317config FIX_EARLYCON_MEM 318 def_bool y 319 320config PGTABLE_LEVELS 321 int 322 default 2 if ARM64_16K_PAGES && ARM64_VA_BITS_36 323 default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42 324 default 3 if ARM64_64K_PAGES && (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) 325 default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39 326 default 3 if ARM64_16K_PAGES && ARM64_VA_BITS_47 327 default 4 if !ARM64_64K_PAGES && ARM64_VA_BITS_48 328 329config ARCH_SUPPORTS_UPROBES 330 def_bool y 331 332config ARCH_PROC_KCORE_TEXT 333 def_bool y 334 335config BROKEN_GAS_INST 336 def_bool !$(as-instr,1:\n.inst 0\n.rept . - 1b\n\nnop\n.endr\n) 337 338config KASAN_SHADOW_OFFSET 339 hex 340 depends on KASAN 341 default 0xdfffa00000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && !KASAN_SW_TAGS 342 default 0xdfffd00000000000 if ARM64_VA_BITS_47 && !KASAN_SW_TAGS 343 default 0xdffffe8000000000 if ARM64_VA_BITS_42 && !KASAN_SW_TAGS 344 default 0xdfffffd000000000 if ARM64_VA_BITS_39 && !KASAN_SW_TAGS 345 default 0xdffffffa00000000 if ARM64_VA_BITS_36 && !KASAN_SW_TAGS 346 default 0xefff900000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && KASAN_SW_TAGS 347 default 0xefffc80000000000 if ARM64_VA_BITS_47 && KASAN_SW_TAGS 348 default 0xeffffe4000000000 if ARM64_VA_BITS_42 && KASAN_SW_TAGS 349 default 0xefffffc800000000 if ARM64_VA_BITS_39 && KASAN_SW_TAGS 350 default 0xeffffff900000000 if ARM64_VA_BITS_36 && KASAN_SW_TAGS 351 default 0xffffffffffffffff 352 353source "arch/arm64/Kconfig.platforms" 354 355menu "Kernel Features" 356 357menu "ARM errata workarounds via the alternatives framework" 358 359config ARM64_WORKAROUND_CLEAN_CACHE 360 bool 361 362config ARM64_ERRATUM_826319 363 bool "Cortex-A53: 826319: System might deadlock if a write cannot complete until read data is accepted" 364 default y 365 select ARM64_WORKAROUND_CLEAN_CACHE 366 help 367 This option adds an alternative code sequence to work around ARM 368 erratum 826319 on Cortex-A53 parts up to r0p2 with an AMBA 4 ACE or 369 AXI master interface and an L2 cache. 370 371 If a Cortex-A53 uses an AMBA AXI4 ACE interface to other processors 372 and is unable to accept a certain write via this interface, it will 373 not progress on read data presented on the read data channel and the 374 system can deadlock. 375 376 The workaround promotes data cache clean instructions to 377 data cache clean-and-invalidate. 378 Please note that this does not necessarily enable the workaround, 379 as it depends on the alternative framework, which will only patch 380 the kernel if an affected CPU is detected. 381 382 If unsure, say Y. 383 384config ARM64_ERRATUM_827319 385 bool "Cortex-A53: 827319: Data cache clean instructions might cause overlapping transactions to the interconnect" 386 default y 387 select ARM64_WORKAROUND_CLEAN_CACHE 388 help 389 This option adds an alternative code sequence to work around ARM 390 erratum 827319 on Cortex-A53 parts up to r0p2 with an AMBA 5 CHI 391 master interface and an L2 cache. 392 393 Under certain conditions this erratum can cause a clean line eviction 394 to occur at the same time as another transaction to the same address 395 on the AMBA 5 CHI interface, which can cause data corruption if the 396 interconnect reorders the two transactions. 397 398 The workaround promotes data cache clean instructions to 399 data cache clean-and-invalidate. 400 Please note that this does not necessarily enable the workaround, 401 as it depends on the alternative framework, which will only patch 402 the kernel if an affected CPU is detected. 403 404 If unsure, say Y. 405 406config ARM64_ERRATUM_824069 407 bool "Cortex-A53: 824069: Cache line might not be marked as clean after a CleanShared snoop" 408 default y 409 select ARM64_WORKAROUND_CLEAN_CACHE 410 help 411 This option adds an alternative code sequence to work around ARM 412 erratum 824069 on Cortex-A53 parts up to r0p2 when it is connected 413 to a coherent interconnect. 414 415 If a Cortex-A53 processor is executing a store or prefetch for 416 write instruction at the same time as a processor in another 417 cluster is executing a cache maintenance operation to the same 418 address, then this erratum might cause a clean cache line to be 419 incorrectly marked as dirty. 420 421 The workaround promotes data cache clean instructions to 422 data cache clean-and-invalidate. 423 Please note that this option does not necessarily enable the 424 workaround, as it depends on the alternative framework, which will 425 only patch the kernel if an affected CPU is detected. 426 427 If unsure, say Y. 428 429config ARM64_ERRATUM_819472 430 bool "Cortex-A53: 819472: Store exclusive instructions might cause data corruption" 431 default y 432 select ARM64_WORKAROUND_CLEAN_CACHE 433 help 434 This option adds an alternative code sequence to work around ARM 435 erratum 819472 on Cortex-A53 parts up to r0p1 with an L2 cache 436 present when it is connected to a coherent interconnect. 437 438 If the processor is executing a load and store exclusive sequence at 439 the same time as a processor in another cluster is executing a cache 440 maintenance operation to the same address, then this erratum might 441 cause data corruption. 442 443 The workaround promotes data cache clean instructions to 444 data cache clean-and-invalidate. 445 Please note that this does not necessarily enable the workaround, 446 as it depends on the alternative framework, which will only patch 447 the kernel if an affected CPU is detected. 448 449 If unsure, say Y. 450 451config ARM64_ERRATUM_832075 452 bool "Cortex-A57: 832075: possible deadlock on mixing exclusive memory accesses with device loads" 453 default y 454 help 455 This option adds an alternative code sequence to work around ARM 456 erratum 832075 on Cortex-A57 parts up to r1p2. 457 458 Affected Cortex-A57 parts might deadlock when exclusive load/store 459 instructions to Write-Back memory are mixed with Device loads. 460 461 The workaround is to promote device loads to use Load-Acquire 462 semantics. 463 Please note that this does not necessarily enable the workaround, 464 as it depends on the alternative framework, which will only patch 465 the kernel if an affected CPU is detected. 466 467 If unsure, say Y. 468 469config ARM64_ERRATUM_834220 470 bool "Cortex-A57: 834220: Stage 2 translation fault might be incorrectly reported in presence of a Stage 1 fault" 471 depends on KVM 472 default y 473 help 474 This option adds an alternative code sequence to work around ARM 475 erratum 834220 on Cortex-A57 parts up to r1p2. 476 477 Affected Cortex-A57 parts might report a Stage 2 translation 478 fault as the result of a Stage 1 fault for load crossing a 479 page boundary when there is a permission or device memory 480 alignment fault at Stage 1 and a translation fault at Stage 2. 481 482 The workaround is to verify that the Stage 1 translation 483 doesn't generate a fault before handling the Stage 2 fault. 484 Please note that this does not necessarily enable the workaround, 485 as it depends on the alternative framework, which will only patch 486 the kernel if an affected CPU is detected. 487 488 If unsure, say Y. 489 490config ARM64_ERRATUM_1742098 491 bool "Cortex-A57/A72: 1742098: ELR recorded incorrectly on interrupt taken between cryptographic instructions in a sequence" 492 depends on COMPAT 493 default y 494 help 495 This option removes the AES hwcap for aarch32 user-space to 496 workaround erratum 1742098 on Cortex-A57 and Cortex-A72. 497 498 Affected parts may corrupt the AES state if an interrupt is 499 taken between a pair of AES instructions. These instructions 500 are only present if the cryptography extensions are present. 501 All software should have a fallback implementation for CPUs 502 that don't implement the cryptography extensions. 503 504 If unsure, say Y. 505 506config ARM64_ERRATUM_845719 507 bool "Cortex-A53: 845719: a load might read incorrect data" 508 depends on COMPAT 509 default y 510 help 511 This option adds an alternative code sequence to work around ARM 512 erratum 845719 on Cortex-A53 parts up to r0p4. 513 514 When running a compat (AArch32) userspace on an affected Cortex-A53 515 part, a load at EL0 from a virtual address that matches the bottom 32 516 bits of the virtual address used by a recent load at (AArch64) EL1 517 might return incorrect data. 518 519 The workaround is to write the contextidr_el1 register on exception 520 return to a 32-bit task. 521 Please note that this does not necessarily enable the workaround, 522 as it depends on the alternative framework, which will only patch 523 the kernel if an affected CPU is detected. 524 525 If unsure, say Y. 526 527config ARM64_ERRATUM_843419 528 bool "Cortex-A53: 843419: A load or store might access an incorrect address" 529 default y 530 select ARM64_MODULE_PLTS if MODULES 531 help 532 This option links the kernel with '--fix-cortex-a53-843419' and 533 enables PLT support to replace certain ADRP instructions, which can 534 cause subsequent memory accesses to use an incorrect address on 535 Cortex-A53 parts up to r0p4. 536 537 If unsure, say Y. 538 539config ARM64_ERRATUM_1024718 540 bool "Cortex-A55: 1024718: Update of DBM/AP bits without break before make might result in incorrect update" 541 default y 542 help 543 This option adds a workaround for ARM Cortex-A55 Erratum 1024718. 544 545 Affected Cortex-A55 cores (all revisions) could cause incorrect 546 update of the hardware dirty bit when the DBM/AP bits are updated 547 without a break-before-make. The workaround is to disable the usage 548 of hardware DBM locally on the affected cores. CPUs not affected by 549 this erratum will continue to use the feature. 550 551 If unsure, say Y. 552 553config ARM64_ERRATUM_1418040 554 bool "Cortex-A76/Neoverse-N1: MRC read following MRRC read of specific Generic Timer in AArch32 might give incorrect result" 555 default y 556 depends on COMPAT 557 help 558 This option adds a workaround for ARM Cortex-A76/Neoverse-N1 559 errata 1188873 and 1418040. 560 561 Affected Cortex-A76/Neoverse-N1 cores (r0p0 to r3p1) could 562 cause register corruption when accessing the timer registers 563 from AArch32 userspace. 564 565 If unsure, say Y. 566 567config ARM64_WORKAROUND_SPECULATIVE_AT 568 bool 569 570config ARM64_ERRATUM_1165522 571 bool "Cortex-A76: 1165522: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation" 572 default y 573 select ARM64_WORKAROUND_SPECULATIVE_AT 574 help 575 This option adds a workaround for ARM Cortex-A76 erratum 1165522. 576 577 Affected Cortex-A76 cores (r0p0, r1p0, r2p0) could end-up with 578 corrupted TLBs by speculating an AT instruction during a guest 579 context switch. 580 581 If unsure, say Y. 582 583config ARM64_ERRATUM_1319367 584 bool "Cortex-A57/A72: 1319537: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation" 585 default y 586 select ARM64_WORKAROUND_SPECULATIVE_AT 587 help 588 This option adds work arounds for ARM Cortex-A57 erratum 1319537 589 and A72 erratum 1319367 590 591 Cortex-A57 and A72 cores could end-up with corrupted TLBs by 592 speculating an AT instruction during a guest context switch. 593 594 If unsure, say Y. 595 596config ARM64_ERRATUM_1530923 597 bool "Cortex-A55: 1530923: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation" 598 default y 599 select ARM64_WORKAROUND_SPECULATIVE_AT 600 help 601 This option adds a workaround for ARM Cortex-A55 erratum 1530923. 602 603 Affected Cortex-A55 cores (r0p0, r0p1, r1p0, r2p0) could end-up with 604 corrupted TLBs by speculating an AT instruction during a guest 605 context switch. 606 607 If unsure, say Y. 608 609config ARM64_WORKAROUND_REPEAT_TLBI 610 bool 611 612config ARM64_ERRATUM_1286807 613 bool "Cortex-A76: Modification of the translation table for a virtual address might lead to read-after-read ordering violation" 614 default y 615 select ARM64_WORKAROUND_REPEAT_TLBI 616 help 617 This option adds a workaround for ARM Cortex-A76 erratum 1286807. 618 619 On the affected Cortex-A76 cores (r0p0 to r3p0), if a virtual 620 address for a cacheable mapping of a location is being 621 accessed by a core while another core is remapping the virtual 622 address to a new physical page using the recommended 623 break-before-make sequence, then under very rare circumstances 624 TLBI+DSB completes before a read using the translation being 625 invalidated has been observed by other observers. The 626 workaround repeats the TLBI+DSB operation. 627 628config ARM64_ERRATUM_1463225 629 bool "Cortex-A76: Software Step might prevent interrupt recognition" 630 default y 631 help 632 This option adds a workaround for Arm Cortex-A76 erratum 1463225. 633 634 On the affected Cortex-A76 cores (r0p0 to r3p1), software stepping 635 of a system call instruction (SVC) can prevent recognition of 636 subsequent interrupts when software stepping is disabled in the 637 exception handler of the system call and either kernel debugging 638 is enabled or VHE is in use. 639 640 Work around the erratum by triggering a dummy step exception 641 when handling a system call from a task that is being stepped 642 in a VHE configuration of the kernel. 643 644 If unsure, say Y. 645 646config ARM64_ERRATUM_1542419 647 bool "Neoverse-N1: workaround mis-ordering of instruction fetches" 648 default y 649 help 650 This option adds a workaround for ARM Neoverse-N1 erratum 651 1542419. 652 653 Affected Neoverse-N1 cores could execute a stale instruction when 654 modified by another CPU. The workaround depends on a firmware 655 counterpart. 656 657 Workaround the issue by hiding the DIC feature from EL0. This 658 forces user-space to perform cache maintenance. 659 660 If unsure, say Y. 661 662config ARM64_ERRATUM_1508412 663 bool "Cortex-A77: 1508412: workaround deadlock on sequence of NC/Device load and store exclusive or PAR read" 664 default y 665 help 666 This option adds a workaround for Arm Cortex-A77 erratum 1508412. 667 668 Affected Cortex-A77 cores (r0p0, r1p0) could deadlock on a sequence 669 of a store-exclusive or read of PAR_EL1 and a load with device or 670 non-cacheable memory attributes. The workaround depends on a firmware 671 counterpart. 672 673 KVM guests must also have the workaround implemented or they can 674 deadlock the system. 675 676 Work around the issue by inserting DMB SY barriers around PAR_EL1 677 register reads and warning KVM users. The DMB barrier is sufficient 678 to prevent a speculative PAR_EL1 read. 679 680 If unsure, say Y. 681 682config ARM64_ERRATUM_2457168 683 bool "Cortex-A510: 2457168: workaround for AMEVCNTR01 incrementing incorrectly" 684 depends on ARM64_AMU_EXTN 685 default y 686 help 687 This option adds the workaround for ARM Cortex-A510 erratum 2457168. 688 689 The AMU counter AMEVCNTR01 (constant counter) should increment at the same rate 690 as the system counter. On affected Cortex-A510 cores AMEVCNTR01 increments 691 incorrectly giving a significantly higher output value. 692 693 Work around this problem by keeping the reference values of affected counters 694 to 0 thus signaling an error case. This effect is the same to firmware disabling 695 affected counters, in which case 0 will be returned when reading the disabled 696 counters. 697 698 If unsure, say Y. 699 700config CAVIUM_ERRATUM_22375 701 bool "Cavium erratum 22375, 24313" 702 default y 703 help 704 Enable workaround for errata 22375 and 24313. 705 706 This implements two gicv3-its errata workarounds for ThunderX. Both 707 with a small impact affecting only ITS table allocation. 708 709 erratum 22375: only alloc 8MB table size 710 erratum 24313: ignore memory access type 711 712 The fixes are in ITS initialization and basically ignore memory access 713 type and table size provided by the TYPER and BASER registers. 714 715 If unsure, say Y. 716 717config CAVIUM_ERRATUM_23144 718 bool "Cavium erratum 23144: ITS SYNC hang on dual socket system" 719 depends on NUMA 720 default y 721 help 722 ITS SYNC command hang for cross node io and collections/cpu mapping. 723 724 If unsure, say Y. 725 726config CAVIUM_ERRATUM_23154 727 bool "Cavium erratum 23154: Access to ICC_IAR1_EL1 is not sync'ed" 728 default y 729 help 730 The gicv3 of ThunderX requires a modified version for 731 reading the IAR status to ensure data synchronization 732 (access to icc_iar1_el1 is not sync'ed before and after). 733 734 If unsure, say Y. 735 736config CAVIUM_ERRATUM_27456 737 bool "Cavium erratum 27456: Broadcast TLBI instructions may cause icache corruption" 738 default y 739 help 740 On ThunderX T88 pass 1.x through 2.1 parts, broadcast TLBI 741 instructions may cause the icache to become corrupted if it 742 contains data for a non-current ASID. The fix is to 743 invalidate the icache when changing the mm context. 744 745 If unsure, say Y. 746 747config CAVIUM_ERRATUM_30115 748 bool "Cavium erratum 30115: Guest may disable interrupts in host" 749 default y 750 help 751 On ThunderX T88 pass 1.x through 2.2, T81 pass 1.0 through 752 1.2, and T83 Pass 1.0, KVM guest execution may disable 753 interrupts in host. Trapping both GICv3 group-0 and group-1 754 accesses sidesteps the issue. 755 756 If unsure, say Y. 757 758config CAVIUM_TX2_ERRATUM_219 759 bool "Cavium ThunderX2 erratum 219: PRFM between TTBR change and ISB fails" 760 default y 761 help 762 On Cavium ThunderX2, a load, store or prefetch instruction between a 763 TTBR update and the corresponding context synchronizing operation can 764 cause a spurious Data Abort to be delivered to any hardware thread in 765 the CPU core. 766 767 Work around the issue by avoiding the problematic code sequence and 768 trapping KVM guest TTBRx_EL1 writes to EL2 when SMT is enabled. The 769 trap handler performs the corresponding register access, skips the 770 instruction and ensures context synchronization by virtue of the 771 exception return. 772 773 If unsure, say Y. 774 775config FUJITSU_ERRATUM_010001 776 bool "Fujitsu-A64FX erratum E#010001: Undefined fault may occur wrongly" 777 default y 778 help 779 This option adds a workaround for Fujitsu-A64FX erratum E#010001. 780 On some variants of the Fujitsu-A64FX cores ver(1.0, 1.1), memory 781 accesses may cause undefined fault (Data abort, DFSC=0b111111). 782 This fault occurs under a specific hardware condition when a 783 load/store instruction performs an address translation using: 784 case-1 TTBR0_EL1 with TCR_EL1.NFD0 == 1. 785 case-2 TTBR0_EL2 with TCR_EL2.NFD0 == 1. 786 case-3 TTBR1_EL1 with TCR_EL1.NFD1 == 1. 787 case-4 TTBR1_EL2 with TCR_EL2.NFD1 == 1. 788 789 The workaround is to ensure these bits are clear in TCR_ELx. 790 The workaround only affects the Fujitsu-A64FX. 791 792 If unsure, say Y. 793 794config HISILICON_ERRATUM_161600802 795 bool "Hip07 161600802: Erroneous redistributor VLPI base" 796 default y 797 help 798 The HiSilicon Hip07 SoC uses the wrong redistributor base 799 when issued ITS commands such as VMOVP and VMAPP, and requires 800 a 128kB offset to be applied to the target address in this commands. 801 802 If unsure, say Y. 803 804config QCOM_FALKOR_ERRATUM_1003 805 bool "Falkor E1003: Incorrect translation due to ASID change" 806 default y 807 help 808 On Falkor v1, an incorrect ASID may be cached in the TLB when ASID 809 and BADDR are changed together in TTBRx_EL1. Since we keep the ASID 810 in TTBR1_EL1, this situation only occurs in the entry trampoline and 811 then only for entries in the walk cache, since the leaf translation 812 is unchanged. Work around the erratum by invalidating the walk cache 813 entries for the trampoline before entering the kernel proper. 814 815config QCOM_FALKOR_ERRATUM_1009 816 bool "Falkor E1009: Prematurely complete a DSB after a TLBI" 817 default y 818 select ARM64_WORKAROUND_REPEAT_TLBI 819 help 820 On Falkor v1, the CPU may prematurely complete a DSB following a 821 TLBI xxIS invalidate maintenance operation. Repeat the TLBI operation 822 one more time to fix the issue. 823 824 If unsure, say Y. 825 826config QCOM_QDF2400_ERRATUM_0065 827 bool "QDF2400 E0065: Incorrect GITS_TYPER.ITT_Entry_size" 828 default y 829 help 830 On Qualcomm Datacenter Technologies QDF2400 SoC, ITS hardware reports 831 ITE size incorrectly. The GITS_TYPER.ITT_Entry_size field should have 832 been indicated as 16Bytes (0xf), not 8Bytes (0x7). 833 834 If unsure, say Y. 835 836config QCOM_FALKOR_ERRATUM_E1041 837 bool "Falkor E1041: Speculative instruction fetches might cause errant memory access" 838 default y 839 help 840 Falkor CPU may speculatively fetch instructions from an improper 841 memory location when MMU translation is changed from SCTLR_ELn[M]=1 842 to SCTLR_ELn[M]=0. Prefix an ISB instruction to fix the problem. 843 844 If unsure, say Y. 845 846config SOCIONEXT_SYNQUACER_PREITS 847 bool "Socionext Synquacer: Workaround for GICv3 pre-ITS" 848 default y 849 help 850 Socionext Synquacer SoCs implement a separate h/w block to generate 851 MSI doorbell writes with non-zero values for the device ID. 852 853 If unsure, say Y. 854 855endmenu 856 857 858choice 859 prompt "Page size" 860 default ARM64_4K_PAGES 861 help 862 Page size (translation granule) configuration. 863 864config ARM64_4K_PAGES 865 bool "4KB" 866 help 867 This feature enables 4KB pages support. 868 869config ARM64_16K_PAGES 870 bool "16KB" 871 help 872 The system will use 16KB pages support. AArch32 emulation 873 requires applications compiled with 16K (or a multiple of 16K) 874 aligned segments. 875 876config ARM64_64K_PAGES 877 bool "64KB" 878 help 879 This feature enables 64KB pages support (4KB by default) 880 allowing only two levels of page tables and faster TLB 881 look-up. AArch32 emulation requires applications compiled 882 with 64K aligned segments. 883 884endchoice 885 886choice 887 prompt "Virtual address space size" 888 default ARM64_VA_BITS_39 if ARM64_4K_PAGES 889 default ARM64_VA_BITS_47 if ARM64_16K_PAGES 890 default ARM64_VA_BITS_42 if ARM64_64K_PAGES 891 help 892 Allows choosing one of multiple possible virtual address 893 space sizes. The level of translation table is determined by 894 a combination of page size and virtual address space size. 895 896config ARM64_VA_BITS_36 897 bool "36-bit" if EXPERT 898 depends on ARM64_16K_PAGES 899 900config ARM64_VA_BITS_39 901 bool "39-bit" 902 depends on ARM64_4K_PAGES 903 904config ARM64_VA_BITS_42 905 bool "42-bit" 906 depends on ARM64_64K_PAGES 907 908config ARM64_VA_BITS_47 909 bool "47-bit" 910 depends on ARM64_16K_PAGES 911 912config ARM64_VA_BITS_48 913 bool "48-bit" 914 915config ARM64_VA_BITS_52 916 bool "52-bit" 917 depends on ARM64_64K_PAGES && (ARM64_PAN || !ARM64_SW_TTBR0_PAN) 918 help 919 Enable 52-bit virtual addressing for userspace when explicitly 920 requested via a hint to mmap(). The kernel will also use 52-bit 921 virtual addresses for its own mappings (provided HW support for 922 this feature is available, otherwise it reverts to 48-bit). 923 924 NOTE: Enabling 52-bit virtual addressing in conjunction with 925 ARMv8.3 Pointer Authentication will result in the PAC being 926 reduced from 7 bits to 3 bits, which may have a significant 927 impact on its susceptibility to brute-force attacks. 928 929 If unsure, select 48-bit virtual addressing instead. 930 931endchoice 932 933config ARM64_FORCE_52BIT 934 bool "Force 52-bit virtual addresses for userspace" 935 depends on ARM64_VA_BITS_52 && EXPERT 936 help 937 For systems with 52-bit userspace VAs enabled, the kernel will attempt 938 to maintain compatibility with older software by providing 48-bit VAs 939 unless a hint is supplied to mmap. 940 941 This configuration option disables the 48-bit compatibility logic, and 942 forces all userspace addresses to be 52-bit on HW that supports it. One 943 should only enable this configuration option for stress testing userspace 944 memory management code. If unsure say N here. 945 946config ARM64_VA_BITS 947 int 948 default 36 if ARM64_VA_BITS_36 949 default 39 if ARM64_VA_BITS_39 950 default 42 if ARM64_VA_BITS_42 951 default 47 if ARM64_VA_BITS_47 952 default 48 if ARM64_VA_BITS_48 953 default 52 if ARM64_VA_BITS_52 954 955choice 956 prompt "Physical address space size" 957 default ARM64_PA_BITS_48 958 help 959 Choose the maximum physical address range that the kernel will 960 support. 961 962config ARM64_PA_BITS_48 963 bool "48-bit" 964 965config ARM64_PA_BITS_52 966 bool "52-bit (ARMv8.2)" 967 depends on ARM64_64K_PAGES 968 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN 969 help 970 Enable support for a 52-bit physical address space, introduced as 971 part of the ARMv8.2-LPA extension. 972 973 With this enabled, the kernel will also continue to work on CPUs that 974 do not support ARMv8.2-LPA, but with some added memory overhead (and 975 minor performance overhead). 976 977endchoice 978 979config ARM64_PA_BITS 980 int 981 default 48 if ARM64_PA_BITS_48 982 default 52 if ARM64_PA_BITS_52 983 984choice 985 prompt "Endianness" 986 default CPU_LITTLE_ENDIAN 987 help 988 Select the endianness of data accesses performed by the CPU. Userspace 989 applications will need to be compiled and linked for the endianness 990 that is selected here. 991 992config CPU_BIG_ENDIAN 993 bool "Build big-endian kernel" 994 depends on !LD_IS_LLD || LLD_VERSION >= 130000 995 help 996 Say Y if you plan on running a kernel with a big-endian userspace. 997 998config CPU_LITTLE_ENDIAN 999 bool "Build little-endian kernel" 1000 help 1001 Say Y if you plan on running a kernel with a little-endian userspace. 1002 This is usually the case for distributions targeting arm64. 1003 1004endchoice 1005 1006config SCHED_MC 1007 bool "Multi-core scheduler support" 1008 help 1009 Multi-core scheduler support improves the CPU scheduler's decision 1010 making when dealing with multi-core CPU chips at a cost of slightly 1011 increased overhead in some places. If unsure say N here. 1012 1013config SCHED_SMT 1014 bool "SMT scheduler support" 1015 help 1016 Improves the CPU scheduler's decision making when dealing with 1017 MultiThreading at a cost of slightly increased overhead in some 1018 places. If unsure say N here. 1019 1020config NR_CPUS 1021 int "Maximum number of CPUs (2-4096)" 1022 range 2 4096 1023 default "256" 1024 1025config HOTPLUG_CPU 1026 bool "Support for hot-pluggable CPUs" 1027 select GENERIC_IRQ_MIGRATION 1028 help 1029 Say Y here to experiment with turning CPUs off and on. CPUs 1030 can be controlled through /sys/devices/system/cpu. 1031 1032# Common NUMA Features 1033config NUMA 1034 bool "NUMA Memory Allocation and Scheduler Support" 1035 select ACPI_NUMA if ACPI 1036 select OF_NUMA 1037 help 1038 Enable NUMA (Non-Uniform Memory Access) support. 1039 1040 The kernel will try to allocate memory used by a CPU on the 1041 local memory of the CPU and add some more 1042 NUMA awareness to the kernel. 1043 1044config NODES_SHIFT 1045 int "Maximum NUMA Nodes (as a power of 2)" 1046 range 1 10 1047 default "4" 1048 depends on NEED_MULTIPLE_NODES 1049 help 1050 Specify the maximum number of NUMA Nodes available on the target 1051 system. Increases memory reserved to accommodate various tables. 1052 1053config USE_PERCPU_NUMA_NODE_ID 1054 def_bool y 1055 depends on NUMA 1056 1057config HAVE_SETUP_PER_CPU_AREA 1058 def_bool y 1059 depends on NUMA 1060 1061config NEED_PER_CPU_EMBED_FIRST_CHUNK 1062 def_bool y 1063 depends on NUMA 1064 1065source "kernel/Kconfig.hz" 1066 1067config ARCH_SUPPORTS_DEBUG_PAGEALLOC 1068 def_bool y 1069 1070config ARCH_SPARSEMEM_ENABLE 1071 def_bool y 1072 select SPARSEMEM_VMEMMAP_ENABLE 1073 1074config ARCH_SPARSEMEM_DEFAULT 1075 def_bool ARCH_SPARSEMEM_ENABLE 1076 1077config ARCH_SELECT_MEMORY_MODEL 1078 def_bool ARCH_SPARSEMEM_ENABLE 1079 1080config ARCH_FLATMEM_ENABLE 1081 def_bool !NUMA 1082 1083config HAVE_ARCH_PFN_VALID 1084 def_bool y 1085 1086config HW_PERF_EVENTS 1087 def_bool y 1088 depends on ARM_PMU 1089 1090config SYS_SUPPORTS_HUGETLBFS 1091 def_bool y 1092 1093config ARCH_WANT_HUGE_PMD_SHARE 1094 1095config ARCH_HAS_CACHE_LINE_SIZE 1096 def_bool y 1097 1098config ARCH_ENABLE_SPLIT_PMD_PTLOCK 1099 def_bool y if PGTABLE_LEVELS > 2 1100 1101# Supported by clang >= 7.0 1102config CC_HAVE_SHADOW_CALL_STACK 1103 def_bool $(cc-option, -fsanitize=shadow-call-stack -ffixed-x18) 1104 1105config PARAVIRT 1106 bool "Enable paravirtualization code" 1107 help 1108 This changes the kernel so it can modify itself when it is run 1109 under a hypervisor, potentially improving performance significantly 1110 over full virtualization. 1111 1112config PARAVIRT_TIME_ACCOUNTING 1113 bool "Paravirtual steal time accounting" 1114 select PARAVIRT 1115 help 1116 Select this option to enable fine granularity task steal time 1117 accounting. Time spent executing other tasks in parallel with 1118 the current vCPU is discounted from the vCPU power. To account for 1119 that, there can be a small performance impact. 1120 1121 If in doubt, say N here. 1122 1123config KEXEC 1124 depends on PM_SLEEP_SMP 1125 select KEXEC_CORE 1126 bool "kexec system call" 1127 help 1128 kexec is a system call that implements the ability to shutdown your 1129 current kernel, and to start another kernel. It is like a reboot 1130 but it is independent of the system firmware. And like a reboot 1131 you can start any kernel with it, not just Linux. 1132 1133config KEXEC_FILE 1134 bool "kexec file based system call" 1135 select KEXEC_CORE 1136 help 1137 This is new version of kexec system call. This system call is 1138 file based and takes file descriptors as system call argument 1139 for kernel and initramfs as opposed to list of segments as 1140 accepted by previous system call. 1141 1142config KEXEC_SIG 1143 bool "Verify kernel signature during kexec_file_load() syscall" 1144 depends on KEXEC_FILE 1145 help 1146 Select this option to verify a signature with loaded kernel 1147 image. If configured, any attempt of loading a image without 1148 valid signature will fail. 1149 1150 In addition to that option, you need to enable signature 1151 verification for the corresponding kernel image type being 1152 loaded in order for this to work. 1153 1154config KEXEC_IMAGE_VERIFY_SIG 1155 bool "Enable Image signature verification support" 1156 default y 1157 depends on KEXEC_SIG 1158 depends on EFI && SIGNED_PE_FILE_VERIFICATION 1159 help 1160 Enable Image signature verification support. 1161 1162comment "Support for PE file signature verification disabled" 1163 depends on KEXEC_SIG 1164 depends on !EFI || !SIGNED_PE_FILE_VERIFICATION 1165 1166config CRASH_DUMP 1167 bool "Build kdump crash kernel" 1168 help 1169 Generate crash dump after being started by kexec. This should 1170 be normally only set in special crash dump kernels which are 1171 loaded in the main kernel with kexec-tools into a specially 1172 reserved region and then later executed after a crash by 1173 kdump/kexec. 1174 1175 For more details see Documentation/admin-guide/kdump/kdump.rst 1176 1177config XEN_DOM0 1178 def_bool y 1179 depends on XEN 1180 1181config XEN 1182 bool "Xen guest support on ARM64" 1183 depends on ARM64 && OF 1184 select SWIOTLB_XEN 1185 select PARAVIRT 1186 help 1187 Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64. 1188 1189config FORCE_MAX_ZONEORDER 1190 int 1191 default "14" if (ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE) 1192 default "12" if (ARM64_16K_PAGES && TRANSPARENT_HUGEPAGE) 1193 default "11" 1194 help 1195 The kernel memory allocator divides physically contiguous memory 1196 blocks into "zones", where each zone is a power of two number of 1197 pages. This option selects the largest power of two that the kernel 1198 keeps in the memory allocator. If you need to allocate very large 1199 blocks of physically contiguous memory, then you may need to 1200 increase this value. 1201 1202 This config option is actually maximum order plus one. For example, 1203 a value of 11 means that the largest free memory block is 2^10 pages. 1204 1205 We make sure that we can allocate upto a HugePage size for each configuration. 1206 Hence we have : 1207 MAX_ORDER = (PMD_SHIFT - PAGE_SHIFT) + 1 => PAGE_SHIFT - 2 1208 1209 However for 4K, we choose a higher default value, 11 as opposed to 10, giving us 1210 4M allocations matching the default size used by generic code. 1211 1212config UNMAP_KERNEL_AT_EL0 1213 bool "Unmap kernel when running in userspace (aka \"KAISER\")" if EXPERT 1214 default y 1215 help 1216 Speculation attacks against some high-performance processors can 1217 be used to bypass MMU permission checks and leak kernel data to 1218 userspace. This can be defended against by unmapping the kernel 1219 when running in userspace, mapping it back in on exception entry 1220 via a trampoline page in the vector table. 1221 1222 If unsure, say Y. 1223 1224config MITIGATE_SPECTRE_BRANCH_HISTORY 1225 bool "Mitigate Spectre style attacks against branch history" if EXPERT 1226 default y 1227 help 1228 Speculation attacks against some high-performance processors can 1229 make use of branch history to influence future speculation. 1230 When taking an exception from user-space, a sequence of branches 1231 or a firmware call overwrites the branch history. 1232 1233config RODATA_FULL_DEFAULT_ENABLED 1234 bool "Apply r/o permissions of VM areas also to their linear aliases" 1235 default y 1236 help 1237 Apply read-only attributes of VM areas to the linear alias of 1238 the backing pages as well. This prevents code or read-only data 1239 from being modified (inadvertently or intentionally) via another 1240 mapping of the same memory page. This additional enhancement can 1241 be turned off at runtime by passing rodata=[off|on] (and turned on 1242 with rodata=full if this option is set to 'n') 1243 1244 This requires the linear region to be mapped down to pages, 1245 which may adversely affect performance in some cases. 1246 1247config ARM64_SW_TTBR0_PAN 1248 bool "Emulate Privileged Access Never using TTBR0_EL1 switching" 1249 help 1250 Enabling this option prevents the kernel from accessing 1251 user-space memory directly by pointing TTBR0_EL1 to a reserved 1252 zeroed area and reserved ASID. The user access routines 1253 restore the valid TTBR0_EL1 temporarily. 1254 1255config ARM64_TAGGED_ADDR_ABI 1256 bool "Enable the tagged user addresses syscall ABI" 1257 default y 1258 help 1259 When this option is enabled, user applications can opt in to a 1260 relaxed ABI via prctl() allowing tagged addresses to be passed 1261 to system calls as pointer arguments. For details, see 1262 Documentation/arm64/tagged-address-abi.rst. 1263 1264menuconfig COMPAT 1265 bool "Kernel support for 32-bit EL0" 1266 depends on ARM64_4K_PAGES || EXPERT 1267 select COMPAT_BINFMT_ELF if BINFMT_ELF 1268 select HAVE_UID16 1269 select OLD_SIGSUSPEND3 1270 select COMPAT_OLD_SIGACTION 1271 help 1272 This option enables support for a 32-bit EL0 running under a 64-bit 1273 kernel at EL1. AArch32-specific components such as system calls, 1274 the user helper functions, VFP support and the ptrace interface are 1275 handled appropriately by the kernel. 1276 1277 If you use a page size other than 4KB (i.e, 16KB or 64KB), please be aware 1278 that you will only be able to execute AArch32 binaries that were compiled 1279 with page size aligned segments. 1280 1281 If you want to execute 32-bit userspace applications, say Y. 1282 1283if COMPAT 1284 1285config KUSER_HELPERS 1286 bool "Enable kuser helpers page for 32-bit applications" 1287 default y 1288 help 1289 Warning: disabling this option may break 32-bit user programs. 1290 1291 Provide kuser helpers to compat tasks. The kernel provides 1292 helper code to userspace in read only form at a fixed location 1293 to allow userspace to be independent of the CPU type fitted to 1294 the system. This permits binaries to be run on ARMv4 through 1295 to ARMv8 without modification. 1296 1297 See Documentation/arm/kernel_user_helpers.rst for details. 1298 1299 However, the fixed address nature of these helpers can be used 1300 by ROP (return orientated programming) authors when creating 1301 exploits. 1302 1303 If all of the binaries and libraries which run on your platform 1304 are built specifically for your platform, and make no use of 1305 these helpers, then you can turn this option off to hinder 1306 such exploits. However, in that case, if a binary or library 1307 relying on those helpers is run, it will not function correctly. 1308 1309 Say N here only if you are absolutely certain that you do not 1310 need these helpers; otherwise, the safe option is to say Y. 1311 1312config COMPAT_VDSO 1313 bool "Enable vDSO for 32-bit applications" 1314 depends on !CPU_BIG_ENDIAN 1315 depends on (CC_IS_CLANG && LD_IS_LLD) || "$(CROSS_COMPILE_COMPAT)" != "" 1316 select GENERIC_COMPAT_VDSO 1317 default y 1318 help 1319 Place in the process address space of 32-bit applications an 1320 ELF shared object providing fast implementations of gettimeofday 1321 and clock_gettime. 1322 1323 You must have a 32-bit build of glibc 2.22 or later for programs 1324 to seamlessly take advantage of this. 1325 1326config THUMB2_COMPAT_VDSO 1327 bool "Compile the 32-bit vDSO for Thumb-2 mode" if EXPERT 1328 depends on COMPAT_VDSO 1329 default y 1330 help 1331 Compile the compat vDSO with '-mthumb -fomit-frame-pointer' if y, 1332 otherwise with '-marm'. 1333 1334menuconfig ARMV8_DEPRECATED 1335 bool "Emulate deprecated/obsolete ARMv8 instructions" 1336 depends on SYSCTL 1337 help 1338 Legacy software support may require certain instructions 1339 that have been deprecated or obsoleted in the architecture. 1340 1341 Enable this config to enable selective emulation of these 1342 features. 1343 1344 If unsure, say Y 1345 1346if ARMV8_DEPRECATED 1347 1348config SWP_EMULATION 1349 bool "Emulate SWP/SWPB instructions" 1350 help 1351 ARMv8 obsoletes the use of A32 SWP/SWPB instructions such that 1352 they are always undefined. Say Y here to enable software 1353 emulation of these instructions for userspace using LDXR/STXR. 1354 This feature can be controlled at runtime with the abi.swp 1355 sysctl which is disabled by default. 1356 1357 In some older versions of glibc [<=2.8] SWP is used during futex 1358 trylock() operations with the assumption that the code will not 1359 be preempted. This invalid assumption may be more likely to fail 1360 with SWP emulation enabled, leading to deadlock of the user 1361 application. 1362 1363 NOTE: when accessing uncached shared regions, LDXR/STXR rely 1364 on an external transaction monitoring block called a global 1365 monitor to maintain update atomicity. If your system does not 1366 implement a global monitor, this option can cause programs that 1367 perform SWP operations to uncached memory to deadlock. 1368 1369 If unsure, say Y 1370 1371config CP15_BARRIER_EMULATION 1372 bool "Emulate CP15 Barrier instructions" 1373 help 1374 The CP15 barrier instructions - CP15ISB, CP15DSB, and 1375 CP15DMB - are deprecated in ARMv8 (and ARMv7). It is 1376 strongly recommended to use the ISB, DSB, and DMB 1377 instructions instead. 1378 1379 Say Y here to enable software emulation of these 1380 instructions for AArch32 userspace code. When this option is 1381 enabled, CP15 barrier usage is traced which can help 1382 identify software that needs updating. This feature can be 1383 controlled at runtime with the abi.cp15_barrier sysctl. 1384 1385 If unsure, say Y 1386 1387config SETEND_EMULATION 1388 bool "Emulate SETEND instruction" 1389 help 1390 The SETEND instruction alters the data-endianness of the 1391 AArch32 EL0, and is deprecated in ARMv8. 1392 1393 Say Y here to enable software emulation of the instruction 1394 for AArch32 userspace code. This feature can be controlled 1395 at runtime with the abi.setend sysctl. 1396 1397 Note: All the cpus on the system must have mixed endian support at EL0 1398 for this feature to be enabled. If a new CPU - which doesn't support mixed 1399 endian - is hotplugged in after this feature has been enabled, there could 1400 be unexpected results in the applications. 1401 1402 If unsure, say Y 1403endif 1404 1405endif 1406 1407menu "ARMv8.1 architectural features" 1408 1409config ARM64_HW_AFDBM 1410 bool "Support for hardware updates of the Access and Dirty page flags" 1411 default y 1412 help 1413 The ARMv8.1 architecture extensions introduce support for 1414 hardware updates of the access and dirty information in page 1415 table entries. When enabled in TCR_EL1 (HA and HD bits) on 1416 capable processors, accesses to pages with PTE_AF cleared will 1417 set this bit instead of raising an access flag fault. 1418 Similarly, writes to read-only pages with the DBM bit set will 1419 clear the read-only bit (AP[2]) instead of raising a 1420 permission fault. 1421 1422 Kernels built with this configuration option enabled continue 1423 to work on pre-ARMv8.1 hardware and the performance impact is 1424 minimal. If unsure, say Y. 1425 1426config ARM64_PAN 1427 bool "Enable support for Privileged Access Never (PAN)" 1428 default y 1429 help 1430 Privileged Access Never (PAN; part of the ARMv8.1 Extensions) 1431 prevents the kernel or hypervisor from accessing user-space (EL0) 1432 memory directly. 1433 1434 Choosing this option will cause any unprotected (not using 1435 copy_to_user et al) memory access to fail with a permission fault. 1436 1437 The feature is detected at runtime, and will remain as a 'nop' 1438 instruction if the cpu does not implement the feature. 1439 1440config AS_HAS_LSE_ATOMICS 1441 def_bool $(as-instr,.arch_extension lse) 1442 1443config ARM64_LSE_ATOMICS 1444 bool 1445 default ARM64_USE_LSE_ATOMICS 1446 depends on AS_HAS_LSE_ATOMICS 1447 1448config ARM64_USE_LSE_ATOMICS 1449 bool "Atomic instructions" 1450 depends on JUMP_LABEL 1451 default y 1452 help 1453 As part of the Large System Extensions, ARMv8.1 introduces new 1454 atomic instructions that are designed specifically to scale in 1455 very large systems. 1456 1457 Say Y here to make use of these instructions for the in-kernel 1458 atomic routines. This incurs a small overhead on CPUs that do 1459 not support these instructions and requires the kernel to be 1460 built with binutils >= 2.25 in order for the new instructions 1461 to be used. 1462 1463config ARM64_VHE 1464 bool "Enable support for Virtualization Host Extensions (VHE)" 1465 default y 1466 help 1467 Virtualization Host Extensions (VHE) allow the kernel to run 1468 directly at EL2 (instead of EL1) on processors that support 1469 it. This leads to better performance for KVM, as they reduce 1470 the cost of the world switch. 1471 1472 Selecting this option allows the VHE feature to be detected 1473 at runtime, and does not affect processors that do not 1474 implement this feature. 1475 1476endmenu 1477 1478menu "ARMv8.2 architectural features" 1479 1480config ARM64_UAO 1481 bool "Enable support for User Access Override (UAO)" 1482 default y 1483 help 1484 User Access Override (UAO; part of the ARMv8.2 Extensions) 1485 causes the 'unprivileged' variant of the load/store instructions to 1486 be overridden to be privileged. 1487 1488 This option changes get_user() and friends to use the 'unprivileged' 1489 variant of the load/store instructions. This ensures that user-space 1490 really did have access to the supplied memory. When addr_limit is 1491 set to kernel memory the UAO bit will be set, allowing privileged 1492 access to kernel memory. 1493 1494 Choosing this option will cause copy_to_user() et al to use user-space 1495 memory permissions. 1496 1497 The feature is detected at runtime, the kernel will use the 1498 regular load/store instructions if the cpu does not implement the 1499 feature. 1500 1501config ARM64_PMEM 1502 bool "Enable support for persistent memory" 1503 select ARCH_HAS_PMEM_API 1504 select ARCH_HAS_UACCESS_FLUSHCACHE 1505 help 1506 Say Y to enable support for the persistent memory API based on the 1507 ARMv8.2 DCPoP feature. 1508 1509 The feature is detected at runtime, and the kernel will use DC CVAC 1510 operations if DC CVAP is not supported (following the behaviour of 1511 DC CVAP itself if the system does not define a point of persistence). 1512 1513config ARM64_RAS_EXTN 1514 bool "Enable support for RAS CPU Extensions" 1515 default y 1516 help 1517 CPUs that support the Reliability, Availability and Serviceability 1518 (RAS) Extensions, part of ARMv8.2 are able to track faults and 1519 errors, classify them and report them to software. 1520 1521 On CPUs with these extensions system software can use additional 1522 barriers to determine if faults are pending and read the 1523 classification from a new set of registers. 1524 1525 Selecting this feature will allow the kernel to use these barriers 1526 and access the new registers if the system supports the extension. 1527 Platform RAS features may additionally depend on firmware support. 1528 1529config ARM64_CNP 1530 bool "Enable support for Common Not Private (CNP) translations" 1531 default y 1532 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN 1533 help 1534 Common Not Private (CNP) allows translation table entries to 1535 be shared between different PEs in the same inner shareable 1536 domain, so the hardware can use this fact to optimise the 1537 caching of such entries in the TLB. 1538 1539 Selecting this option allows the CNP feature to be detected 1540 at runtime, and does not affect PEs that do not implement 1541 this feature. 1542 1543endmenu 1544 1545menu "ARMv8.3 architectural features" 1546 1547config ARM64_PTR_AUTH 1548 bool "Enable support for pointer authentication" 1549 default y 1550 depends on (CC_HAS_SIGN_RETURN_ADDRESS || CC_HAS_BRANCH_PROT_PAC_RET) && AS_HAS_PAC 1551 # Modern compilers insert a .note.gnu.property section note for PAC 1552 # which is only understood by binutils starting with version 2.33.1. 1553 depends on LD_IS_LLD || LD_VERSION >= 233010000 || (CC_IS_GCC && GCC_VERSION < 90100) 1554 depends on !CC_IS_CLANG || AS_HAS_CFI_NEGATE_RA_STATE 1555 depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_REGS) 1556 help 1557 Pointer authentication (part of the ARMv8.3 Extensions) provides 1558 instructions for signing and authenticating pointers against secret 1559 keys, which can be used to mitigate Return Oriented Programming (ROP) 1560 and other attacks. 1561 1562 This option enables these instructions at EL0 (i.e. for userspace). 1563 Choosing this option will cause the kernel to initialise secret keys 1564 for each process at exec() time, with these keys being 1565 context-switched along with the process. 1566 1567 If the compiler supports the -mbranch-protection or 1568 -msign-return-address flag (e.g. GCC 7 or later), then this option 1569 will also cause the kernel itself to be compiled with return address 1570 protection. In this case, and if the target hardware is known to 1571 support pointer authentication, then CONFIG_STACKPROTECTOR can be 1572 disabled with minimal loss of protection. 1573 1574 The feature is detected at runtime. If the feature is not present in 1575 hardware it will not be advertised to userspace/KVM guest nor will it 1576 be enabled. 1577 1578 If the feature is present on the boot CPU but not on a late CPU, then 1579 the late CPU will be parked. Also, if the boot CPU does not have 1580 address auth and the late CPU has then the late CPU will still boot 1581 but with the feature disabled. On such a system, this option should 1582 not be selected. 1583 1584 This feature works with FUNCTION_GRAPH_TRACER option only if 1585 DYNAMIC_FTRACE_WITH_REGS is enabled. 1586 1587config CC_HAS_BRANCH_PROT_PAC_RET 1588 # GCC 9 or later, clang 8 or later 1589 def_bool $(cc-option,-mbranch-protection=pac-ret+leaf) 1590 1591config CC_HAS_SIGN_RETURN_ADDRESS 1592 # GCC 7, 8 1593 def_bool $(cc-option,-msign-return-address=all) 1594 1595config AS_HAS_PAC 1596 def_bool $(cc-option,-Wa$(comma)-march=armv8.3-a) 1597 1598config AS_HAS_CFI_NEGATE_RA_STATE 1599 def_bool $(as-instr,.cfi_startproc\n.cfi_negate_ra_state\n.cfi_endproc\n) 1600 1601endmenu 1602 1603menu "ARMv8.4 architectural features" 1604 1605config ARM64_AMU_EXTN 1606 bool "Enable support for the Activity Monitors Unit CPU extension" 1607 default y 1608 help 1609 The activity monitors extension is an optional extension introduced 1610 by the ARMv8.4 CPU architecture. This enables support for version 1 1611 of the activity monitors architecture, AMUv1. 1612 1613 To enable the use of this extension on CPUs that implement it, say Y. 1614 1615 Note that for architectural reasons, firmware _must_ implement AMU 1616 support when running on CPUs that present the activity monitors 1617 extension. The required support is present in: 1618 * Version 1.5 and later of the ARM Trusted Firmware 1619 1620 For kernels that have this configuration enabled but boot with broken 1621 firmware, you may need to say N here until the firmware is fixed. 1622 Otherwise you may experience firmware panics or lockups when 1623 accessing the counter registers. Even if you are not observing these 1624 symptoms, the values returned by the register reads might not 1625 correctly reflect reality. Most commonly, the value read will be 0, 1626 indicating that the counter is not enabled. 1627 1628config AS_HAS_ARMV8_4 1629 def_bool $(cc-option,-Wa$(comma)-march=armv8.4-a) 1630 1631config ARM64_TLB_RANGE 1632 bool "Enable support for tlbi range feature" 1633 default y 1634 depends on AS_HAS_ARMV8_4 1635 help 1636 ARMv8.4-TLBI provides TLBI invalidation instruction that apply to a 1637 range of input addresses. 1638 1639 The feature introduces new assembly instructions, and they were 1640 support when binutils >= 2.30. 1641 1642endmenu 1643 1644menu "ARMv8.5 architectural features" 1645 1646config ARM64_BTI 1647 bool "Branch Target Identification support" 1648 default y 1649 help 1650 Branch Target Identification (part of the ARMv8.5 Extensions) 1651 provides a mechanism to limit the set of locations to which computed 1652 branch instructions such as BR or BLR can jump. 1653 1654 To make use of BTI on CPUs that support it, say Y. 1655 1656 BTI is intended to provide complementary protection to other control 1657 flow integrity protection mechanisms, such as the Pointer 1658 authentication mechanism provided as part of the ARMv8.3 Extensions. 1659 For this reason, it does not make sense to enable this option without 1660 also enabling support for pointer authentication. Thus, when 1661 enabling this option you should also select ARM64_PTR_AUTH=y. 1662 1663 Userspace binaries must also be specifically compiled to make use of 1664 this mechanism. If you say N here or the hardware does not support 1665 BTI, such binaries can still run, but you get no additional 1666 enforcement of branch destinations. 1667 1668config ARM64_BTI_KERNEL 1669 bool "Use Branch Target Identification for kernel" 1670 default y 1671 depends on ARM64_BTI 1672 depends on ARM64_PTR_AUTH 1673 depends on CC_HAS_BRANCH_PROT_PAC_RET_BTI 1674 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94697 1675 depends on !CC_IS_GCC || GCC_VERSION >= 100100 1676 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106671 1677 depends on !CC_IS_GCC 1678 # https://github.com/llvm/llvm-project/commit/a88c722e687e6780dcd6a58718350dc76fcc4cc9 1679 depends on !CC_IS_CLANG || CLANG_VERSION >= 120000 1680 depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_REGS) 1681 help 1682 Build the kernel with Branch Target Identification annotations 1683 and enable enforcement of this for kernel code. When this option 1684 is enabled and the system supports BTI all kernel code including 1685 modular code must have BTI enabled. 1686 1687config CC_HAS_BRANCH_PROT_PAC_RET_BTI 1688 # GCC 9 or later, clang 8 or later 1689 def_bool $(cc-option,-mbranch-protection=pac-ret+leaf+bti) 1690 1691config ARM64_E0PD 1692 bool "Enable support for E0PD" 1693 default y 1694 help 1695 E0PD (part of the ARMv8.5 extensions) allows us to ensure 1696 that EL0 accesses made via TTBR1 always fault in constant time, 1697 providing similar benefits to KASLR as those provided by KPTI, but 1698 with lower overhead and without disrupting legitimate access to 1699 kernel memory such as SPE. 1700 1701 This option enables E0PD for TTBR1 where available. 1702 1703config ARCH_RANDOM 1704 bool "Enable support for random number generation" 1705 default y 1706 help 1707 Random number generation (part of the ARMv8.5 Extensions) 1708 provides a high bandwidth, cryptographically secure 1709 hardware random number generator. 1710 1711config ARM64_AS_HAS_MTE 1712 # Initial support for MTE went in binutils 2.32.0, checked with 1713 # ".arch armv8.5-a+memtag" below. However, this was incomplete 1714 # as a late addition to the final architecture spec (LDGM/STGM) 1715 # is only supported in the newer 2.32.x and 2.33 binutils 1716 # versions, hence the extra "stgm" instruction check below. 1717 def_bool $(as-instr,.arch armv8.5-a+memtag\nstgm xzr$(comma)[x0]) 1718 1719config ARM64_MTE 1720 bool "Memory Tagging Extension support" 1721 default y 1722 depends on ARM64_AS_HAS_MTE && ARM64_TAGGED_ADDR_ABI 1723 depends on AS_HAS_LSE_ATOMICS 1724 select ARCH_USES_HIGH_VMA_FLAGS 1725 help 1726 Memory Tagging (part of the ARMv8.5 Extensions) provides 1727 architectural support for run-time, always-on detection of 1728 various classes of memory error to aid with software debugging 1729 to eliminate vulnerabilities arising from memory-unsafe 1730 languages. 1731 1732 This option enables the support for the Memory Tagging 1733 Extension at EL0 (i.e. for userspace). 1734 1735 Selecting this option allows the feature to be detected at 1736 runtime. Any secondary CPU not implementing this feature will 1737 not be allowed a late bring-up. 1738 1739 Userspace binaries that want to use this feature must 1740 explicitly opt in. The mechanism for the userspace is 1741 described in: 1742 1743 Documentation/arm64/memory-tagging-extension.rst. 1744 1745endmenu 1746 1747config ARM64_SVE 1748 bool "ARM Scalable Vector Extension support" 1749 default y 1750 depends on !KVM || ARM64_VHE 1751 help 1752 The Scalable Vector Extension (SVE) is an extension to the AArch64 1753 execution state which complements and extends the SIMD functionality 1754 of the base architecture to support much larger vectors and to enable 1755 additional vectorisation opportunities. 1756 1757 To enable use of this extension on CPUs that implement it, say Y. 1758 1759 On CPUs that support the SVE2 extensions, this option will enable 1760 those too. 1761 1762 Note that for architectural reasons, firmware _must_ implement SVE 1763 support when running on SVE capable hardware. The required support 1764 is present in: 1765 1766 * version 1.5 and later of the ARM Trusted Firmware 1767 * the AArch64 boot wrapper since commit 5e1261e08abf 1768 ("bootwrapper: SVE: Enable SVE for EL2 and below"). 1769 1770 For other firmware implementations, consult the firmware documentation 1771 or vendor. 1772 1773 If you need the kernel to boot on SVE-capable hardware with broken 1774 firmware, you may need to say N here until you get your firmware 1775 fixed. Otherwise, you may experience firmware panics or lockups when 1776 booting the kernel. If unsure and you are not observing these 1777 symptoms, you should assume that it is safe to say Y. 1778 1779 CPUs that support SVE are architecturally required to support the 1780 Virtualization Host Extensions (VHE), so the kernel makes no 1781 provision for supporting SVE alongside KVM without VHE enabled. 1782 Thus, you will need to enable CONFIG_ARM64_VHE if you want to support 1783 KVM in the same kernel image. 1784 1785config ARM64_MODULE_PLTS 1786 bool "Use PLTs to allow module memory to spill over into vmalloc area" 1787 depends on MODULES 1788 select HAVE_MOD_ARCH_SPECIFIC 1789 help 1790 Allocate PLTs when loading modules so that jumps and calls whose 1791 targets are too far away for their relative offsets to be encoded 1792 in the instructions themselves can be bounced via veneers in the 1793 module's PLT. This allows modules to be allocated in the generic 1794 vmalloc area after the dedicated module memory area has been 1795 exhausted. 1796 1797 When running with address space randomization (KASLR), the module 1798 region itself may be too far away for ordinary relative jumps and 1799 calls, and so in that case, module PLTs are required and cannot be 1800 disabled. 1801 1802 Specific errata workaround(s) might also force module PLTs to be 1803 enabled (ARM64_ERRATUM_843419). 1804 1805config ARM64_PSEUDO_NMI 1806 bool "Support for NMI-like interrupts" 1807 select ARM_GIC_V3 1808 help 1809 Adds support for mimicking Non-Maskable Interrupts through the use of 1810 GIC interrupt priority. This support requires version 3 or later of 1811 ARM GIC. 1812 1813 This high priority configuration for interrupts needs to be 1814 explicitly enabled by setting the kernel parameter 1815 "irqchip.gicv3_pseudo_nmi" to 1. 1816 1817 If unsure, say N 1818 1819if ARM64_PSEUDO_NMI 1820config ARM64_DEBUG_PRIORITY_MASKING 1821 bool "Debug interrupt priority masking" 1822 help 1823 This adds runtime checks to functions enabling/disabling 1824 interrupts when using priority masking. The additional checks verify 1825 the validity of ICC_PMR_EL1 when calling concerned functions. 1826 1827 If unsure, say N 1828endif 1829 1830config RELOCATABLE 1831 bool "Build a relocatable kernel image" if EXPERT 1832 select ARCH_HAS_RELR 1833 default y 1834 help 1835 This builds the kernel as a Position Independent Executable (PIE), 1836 which retains all relocation metadata required to relocate the 1837 kernel binary at runtime to a different virtual address than the 1838 address it was linked at. 1839 Since AArch64 uses the RELA relocation format, this requires a 1840 relocation pass at runtime even if the kernel is loaded at the 1841 same address it was linked at. 1842 1843config RANDOMIZE_BASE 1844 bool "Randomize the address of the kernel image" 1845 select ARM64_MODULE_PLTS if MODULES 1846 select RELOCATABLE 1847 help 1848 Randomizes the virtual address at which the kernel image is 1849 loaded, as a security feature that deters exploit attempts 1850 relying on knowledge of the location of kernel internals. 1851 1852 It is the bootloader's job to provide entropy, by passing a 1853 random u64 value in /chosen/kaslr-seed at kernel entry. 1854 1855 When booting via the UEFI stub, it will invoke the firmware's 1856 EFI_RNG_PROTOCOL implementation (if available) to supply entropy 1857 to the kernel proper. In addition, it will randomise the physical 1858 location of the kernel Image as well. 1859 1860 If unsure, say N. 1861 1862config RANDOMIZE_MODULE_REGION_FULL 1863 bool "Randomize the module region over a 4 GB range" 1864 depends on RANDOMIZE_BASE 1865 default y 1866 help 1867 Randomizes the location of the module region inside a 4 GB window 1868 covering the core kernel. This way, it is less likely for modules 1869 to leak information about the location of core kernel data structures 1870 but it does imply that function calls between modules and the core 1871 kernel will need to be resolved via veneers in the module PLT. 1872 1873 When this option is not set, the module region will be randomized over 1874 a limited range that contains the [_stext, _etext] interval of the 1875 core kernel, so branch relocations are always in range. 1876 1877config CC_HAVE_STACKPROTECTOR_SYSREG 1878 def_bool $(cc-option,-mstack-protector-guard=sysreg -mstack-protector-guard-reg=sp_el0 -mstack-protector-guard-offset=0) 1879 1880config STACKPROTECTOR_PER_TASK 1881 def_bool y 1882 depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_SYSREG 1883 1884endmenu 1885 1886menu "Boot options" 1887 1888config ARM64_ACPI_PARKING_PROTOCOL 1889 bool "Enable support for the ARM64 ACPI parking protocol" 1890 depends on ACPI 1891 help 1892 Enable support for the ARM64 ACPI parking protocol. If disabled 1893 the kernel will not allow booting through the ARM64 ACPI parking 1894 protocol even if the corresponding data is present in the ACPI 1895 MADT table. 1896 1897config CMDLINE 1898 string "Default kernel command string" 1899 default "" 1900 help 1901 Provide a set of default command-line options at build time by 1902 entering them here. As a minimum, you should specify the the 1903 root device (e.g. root=/dev/nfs). 1904 1905config CMDLINE_FORCE 1906 bool "Always use the default kernel command string" 1907 depends on CMDLINE != "" 1908 help 1909 Always use the default kernel command string, even if the boot 1910 loader passes other arguments to the kernel. 1911 This is useful if you cannot or don't want to change the 1912 command-line options your boot loader passes to the kernel. 1913 1914config EFI_STUB 1915 bool 1916 1917config EFI 1918 bool "UEFI runtime support" 1919 depends on OF && !CPU_BIG_ENDIAN 1920 depends on KERNEL_MODE_NEON 1921 select ARCH_SUPPORTS_ACPI 1922 select LIBFDT 1923 select UCS2_STRING 1924 select EFI_PARAMS_FROM_FDT 1925 select EFI_RUNTIME_WRAPPERS 1926 select EFI_STUB 1927 select EFI_GENERIC_STUB 1928 default y 1929 help 1930 This option provides support for runtime services provided 1931 by UEFI firmware (such as non-volatile variables, realtime 1932 clock, and platform reset). A UEFI stub is also provided to 1933 allow the kernel to be booted as an EFI application. This 1934 is only useful on systems that have UEFI firmware. 1935 1936config DMI 1937 bool "Enable support for SMBIOS (DMI) tables" 1938 depends on EFI 1939 default y 1940 help 1941 This enables SMBIOS/DMI feature for systems. 1942 1943 This option is only useful on systems that have UEFI firmware. 1944 However, even with this option, the resultant kernel should 1945 continue to boot on existing non-UEFI platforms. 1946 1947endmenu 1948 1949config SYSVIPC_COMPAT 1950 def_bool y 1951 depends on COMPAT && SYSVIPC 1952 1953config ARCH_ENABLE_HUGEPAGE_MIGRATION 1954 def_bool y 1955 depends on HUGETLB_PAGE && MIGRATION 1956 1957config ARCH_ENABLE_THP_MIGRATION 1958 def_bool y 1959 depends on TRANSPARENT_HUGEPAGE 1960 1961menu "Power management options" 1962 1963source "kernel/power/Kconfig" 1964 1965config ARCH_HIBERNATION_POSSIBLE 1966 def_bool y 1967 depends on CPU_PM 1968 1969config ARCH_HIBERNATION_HEADER 1970 def_bool y 1971 depends on HIBERNATION 1972 1973config ARCH_SUSPEND_POSSIBLE 1974 def_bool y 1975 1976endmenu 1977 1978menu "CPU Power Management" 1979 1980source "drivers/cpuidle/Kconfig" 1981 1982source "drivers/cpufreq/Kconfig" 1983 1984endmenu 1985 1986source "drivers/firmware/Kconfig" 1987 1988source "drivers/acpi/Kconfig" 1989 1990source "arch/arm64/kvm/Kconfig" 1991 1992if CRYPTO 1993source "arch/arm64/crypto/Kconfig" 1994endif 1995