1config ARM64 2 def_bool y 3 select ACPI_CCA_REQUIRED if ACPI 4 select ACPI_GENERIC_GSI if ACPI 5 select ACPI_GTDT if ACPI 6 select ACPI_IORT if ACPI 7 select ACPI_REDUCED_HARDWARE_ONLY if ACPI 8 select ACPI_MCFG if (ACPI && PCI) 9 select ACPI_SPCR_TABLE if ACPI 10 select ACPI_PPTT if ACPI 11 select ARCH_CLOCKSOURCE_DATA 12 select ARCH_HAS_DEBUG_VIRTUAL 13 select ARCH_HAS_DEVMEM_IS_ALLOWED 14 select ARCH_HAS_DMA_COHERENT_TO_PFN 15 select ARCH_HAS_DMA_MMAP_PGPROT 16 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 17 select ARCH_HAS_ELF_RANDOMIZE 18 select ARCH_HAS_FAST_MULTIPLIER 19 select ARCH_HAS_FORTIFY_SOURCE 20 select ARCH_HAS_GCOV_PROFILE_ALL 21 select ARCH_HAS_GIGANTIC_PAGE if (MEMORY_ISOLATION && COMPACTION) || CMA 22 select ARCH_HAS_KCOV 23 select ARCH_HAS_MEMBARRIER_SYNC_CORE 24 select ARCH_HAS_PTE_SPECIAL 25 select ARCH_HAS_SETUP_DMA_OPS 26 select ARCH_HAS_SET_MEMORY 27 select ARCH_HAS_STRICT_KERNEL_RWX 28 select ARCH_HAS_STRICT_MODULE_RWX 29 select ARCH_HAS_SYNC_DMA_FOR_DEVICE 30 select ARCH_HAS_SYNC_DMA_FOR_CPU 31 select ARCH_HAS_SYSCALL_WRAPPER 32 select ARCH_HAS_TEARDOWN_DMA_OPS if IOMMU_SUPPORT 33 select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST 34 select ARCH_HAVE_NMI_SAFE_CMPXCHG 35 select ARCH_INLINE_READ_LOCK if !PREEMPT 36 select ARCH_INLINE_READ_LOCK_BH if !PREEMPT 37 select ARCH_INLINE_READ_LOCK_IRQ if !PREEMPT 38 select ARCH_INLINE_READ_LOCK_IRQSAVE if !PREEMPT 39 select ARCH_INLINE_READ_UNLOCK if !PREEMPT 40 select ARCH_INLINE_READ_UNLOCK_BH if !PREEMPT 41 select ARCH_INLINE_READ_UNLOCK_IRQ if !PREEMPT 42 select ARCH_INLINE_READ_UNLOCK_IRQRESTORE if !PREEMPT 43 select ARCH_INLINE_WRITE_LOCK if !PREEMPT 44 select ARCH_INLINE_WRITE_LOCK_BH if !PREEMPT 45 select ARCH_INLINE_WRITE_LOCK_IRQ if !PREEMPT 46 select ARCH_INLINE_WRITE_LOCK_IRQSAVE if !PREEMPT 47 select ARCH_INLINE_WRITE_UNLOCK if !PREEMPT 48 select ARCH_INLINE_WRITE_UNLOCK_BH if !PREEMPT 49 select ARCH_INLINE_WRITE_UNLOCK_IRQ if !PREEMPT 50 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE if !PREEMPT 51 select ARCH_INLINE_SPIN_TRYLOCK if !PREEMPT 52 select ARCH_INLINE_SPIN_TRYLOCK_BH if !PREEMPT 53 select ARCH_INLINE_SPIN_LOCK if !PREEMPT 54 select ARCH_INLINE_SPIN_LOCK_BH if !PREEMPT 55 select ARCH_INLINE_SPIN_LOCK_IRQ if !PREEMPT 56 select ARCH_INLINE_SPIN_LOCK_IRQSAVE if !PREEMPT 57 select ARCH_INLINE_SPIN_UNLOCK if !PREEMPT 58 select ARCH_INLINE_SPIN_UNLOCK_BH if !PREEMPT 59 select ARCH_INLINE_SPIN_UNLOCK_IRQ if !PREEMPT 60 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPT 61 select ARCH_USE_CMPXCHG_LOCKREF 62 select ARCH_USE_QUEUED_RWLOCKS 63 select ARCH_USE_QUEUED_SPINLOCKS 64 select ARCH_SUPPORTS_MEMORY_FAILURE 65 select ARCH_SUPPORTS_ATOMIC_RMW 66 select ARCH_SUPPORTS_INT128 if GCC_VERSION >= 50000 || CC_IS_CLANG 67 select ARCH_SUPPORTS_NUMA_BALANCING 68 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION 69 select ARCH_WANT_FRAME_POINTERS 70 select ARCH_HAS_UBSAN_SANITIZE_ALL 71 select ARM_AMBA 72 select ARM_ARCH_TIMER 73 select ARM_GIC 74 select AUDIT_ARCH_COMPAT_GENERIC 75 select ARM_GIC_V2M if PCI 76 select ARM_GIC_V3 77 select ARM_GIC_V3_ITS if PCI 78 select ARM_PSCI_FW 79 select BUILDTIME_EXTABLE_SORT 80 select CLONE_BACKWARDS 81 select COMMON_CLK 82 select CPU_PM if (SUSPEND || CPU_IDLE) 83 select CRC32 84 select DCACHE_WORD_ACCESS 85 select DMA_DIRECT_REMAP 86 select EDAC_SUPPORT 87 select FRAME_POINTER 88 select GENERIC_ALLOCATOR 89 select GENERIC_ARCH_TOPOLOGY 90 select GENERIC_CLOCKEVENTS 91 select GENERIC_CLOCKEVENTS_BROADCAST 92 select GENERIC_CPU_AUTOPROBE 93 select GENERIC_CPU_VULNERABILITIES 94 select GENERIC_EARLY_IOREMAP 95 select GENERIC_IDLE_POLL_SETUP 96 select GENERIC_IRQ_MULTI_HANDLER 97 select GENERIC_IRQ_PROBE 98 select GENERIC_IRQ_SHOW 99 select GENERIC_IRQ_SHOW_LEVEL 100 select GENERIC_PCI_IOMAP 101 select GENERIC_SCHED_CLOCK 102 select GENERIC_SMP_IDLE_THREAD 103 select GENERIC_STRNCPY_FROM_USER 104 select GENERIC_STRNLEN_USER 105 select GENERIC_TIME_VSYSCALL 106 select HANDLE_DOMAIN_IRQ 107 select HARDIRQS_SW_RESEND 108 select HAVE_PCI 109 select HAVE_ACPI_APEI if (ACPI && EFI) 110 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 111 select HAVE_ARCH_AUDITSYSCALL 112 select HAVE_ARCH_BITREVERSE 113 select HAVE_ARCH_HUGE_VMAP 114 select HAVE_ARCH_JUMP_LABEL 115 select HAVE_ARCH_JUMP_LABEL_RELATIVE 116 select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48) 117 select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN 118 select HAVE_ARCH_KGDB 119 select HAVE_ARCH_MMAP_RND_BITS 120 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT 121 select HAVE_ARCH_PREL32_RELOCATIONS 122 select HAVE_ARCH_SECCOMP_FILTER 123 select HAVE_ARCH_STACKLEAK 124 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 125 select HAVE_ARCH_TRACEHOOK 126 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 127 select HAVE_ARCH_VMAP_STACK 128 select HAVE_ARM_SMCCC 129 select HAVE_EBPF_JIT 130 select HAVE_C_RECORDMCOUNT 131 select HAVE_CMPXCHG_DOUBLE 132 select HAVE_CMPXCHG_LOCAL 133 select HAVE_CONTEXT_TRACKING 134 select HAVE_DEBUG_BUGVERBOSE 135 select HAVE_DEBUG_KMEMLEAK 136 select HAVE_DMA_CONTIGUOUS 137 select HAVE_DYNAMIC_FTRACE 138 select HAVE_EFFICIENT_UNALIGNED_ACCESS 139 select HAVE_FTRACE_MCOUNT_RECORD 140 select HAVE_FUNCTION_TRACER 141 select HAVE_FUNCTION_GRAPH_TRACER 142 select HAVE_GCC_PLUGINS 143 select HAVE_HW_BREAKPOINT if PERF_EVENTS 144 select HAVE_IRQ_TIME_ACCOUNTING 145 select HAVE_MEMBLOCK_NODE_MAP if NUMA 146 select HAVE_NMI 147 select HAVE_PATA_PLATFORM 148 select HAVE_PERF_EVENTS 149 select HAVE_PERF_REGS 150 select HAVE_PERF_USER_STACK_DUMP 151 select HAVE_REGS_AND_STACK_ACCESS_API 152 select HAVE_FUNCTION_ARG_ACCESS_API 153 select HAVE_RCU_TABLE_FREE 154 select HAVE_RSEQ 155 select HAVE_STACKPROTECTOR 156 select HAVE_SYSCALL_TRACEPOINTS 157 select HAVE_KPROBES 158 select HAVE_KRETPROBES 159 select IOMMU_DMA if IOMMU_SUPPORT 160 select IRQ_DOMAIN 161 select IRQ_FORCED_THREADING 162 select MODULES_USE_ELF_RELA 163 select NEED_DMA_MAP_STATE 164 select NEED_SG_DMA_LENGTH 165 select OF 166 select OF_EARLY_FLATTREE 167 select PCI_DOMAINS_GENERIC if PCI 168 select PCI_ECAM if (ACPI && PCI) 169 select PCI_SYSCALL if PCI 170 select POWER_RESET 171 select POWER_SUPPLY 172 select REFCOUNT_FULL 173 select SPARSE_IRQ 174 select SWIOTLB 175 select SYSCTL_EXCEPTION_TRACE 176 select THREAD_INFO_IN_TASK 177 help 178 ARM 64-bit (AArch64) Linux support. 179 180config 64BIT 181 def_bool y 182 183config MMU 184 def_bool y 185 186config ARM64_PAGE_SHIFT 187 int 188 default 16 if ARM64_64K_PAGES 189 default 14 if ARM64_16K_PAGES 190 default 12 191 192config ARM64_CONT_SHIFT 193 int 194 default 5 if ARM64_64K_PAGES 195 default 7 if ARM64_16K_PAGES 196 default 4 197 198config ARCH_MMAP_RND_BITS_MIN 199 default 14 if ARM64_64K_PAGES 200 default 16 if ARM64_16K_PAGES 201 default 18 202 203# max bits determined by the following formula: 204# VA_BITS - PAGE_SHIFT - 3 205config ARCH_MMAP_RND_BITS_MAX 206 default 19 if ARM64_VA_BITS=36 207 default 24 if ARM64_VA_BITS=39 208 default 27 if ARM64_VA_BITS=42 209 default 30 if ARM64_VA_BITS=47 210 default 29 if ARM64_VA_BITS=48 && ARM64_64K_PAGES 211 default 31 if ARM64_VA_BITS=48 && ARM64_16K_PAGES 212 default 33 if ARM64_VA_BITS=48 213 default 14 if ARM64_64K_PAGES 214 default 16 if ARM64_16K_PAGES 215 default 18 216 217config ARCH_MMAP_RND_COMPAT_BITS_MIN 218 default 7 if ARM64_64K_PAGES 219 default 9 if ARM64_16K_PAGES 220 default 11 221 222config ARCH_MMAP_RND_COMPAT_BITS_MAX 223 default 16 224 225config NO_IOPORT_MAP 226 def_bool y if !PCI 227 228config STACKTRACE_SUPPORT 229 def_bool y 230 231config ILLEGAL_POINTER_VALUE 232 hex 233 default 0xdead000000000000 234 235config LOCKDEP_SUPPORT 236 def_bool y 237 238config TRACE_IRQFLAGS_SUPPORT 239 def_bool y 240 241config GENERIC_BUG 242 def_bool y 243 depends on BUG 244 245config GENERIC_BUG_RELATIVE_POINTERS 246 def_bool y 247 depends on GENERIC_BUG 248 249config GENERIC_HWEIGHT 250 def_bool y 251 252config GENERIC_CSUM 253 def_bool y 254 255config GENERIC_CALIBRATE_DELAY 256 def_bool y 257 258config ZONE_DMA32 259 def_bool y 260 261config HAVE_GENERIC_GUP 262 def_bool y 263 264config ARCH_ENABLE_MEMORY_HOTPLUG 265 def_bool y 266 267config SMP 268 def_bool y 269 270config KERNEL_MODE_NEON 271 def_bool y 272 273config FIX_EARLYCON_MEM 274 def_bool y 275 276config PGTABLE_LEVELS 277 int 278 default 2 if ARM64_16K_PAGES && ARM64_VA_BITS_36 279 default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42 280 default 3 if ARM64_64K_PAGES && (ARM64_VA_BITS_48 || ARM64_USER_VA_BITS_52) 281 default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39 282 default 3 if ARM64_16K_PAGES && ARM64_VA_BITS_47 283 default 4 if !ARM64_64K_PAGES && ARM64_VA_BITS_48 284 285config ARCH_SUPPORTS_UPROBES 286 def_bool y 287 288config ARCH_PROC_KCORE_TEXT 289 def_bool y 290 291source "arch/arm64/Kconfig.platforms" 292 293menu "Kernel Features" 294 295menu "ARM errata workarounds via the alternatives framework" 296 297config ARM64_WORKAROUND_CLEAN_CACHE 298 bool 299 300config ARM64_ERRATUM_826319 301 bool "Cortex-A53: 826319: System might deadlock if a write cannot complete until read data is accepted" 302 default y 303 select ARM64_WORKAROUND_CLEAN_CACHE 304 help 305 This option adds an alternative code sequence to work around ARM 306 erratum 826319 on Cortex-A53 parts up to r0p2 with an AMBA 4 ACE or 307 AXI master interface and an L2 cache. 308 309 If a Cortex-A53 uses an AMBA AXI4 ACE interface to other processors 310 and is unable to accept a certain write via this interface, it will 311 not progress on read data presented on the read data channel and the 312 system can deadlock. 313 314 The workaround promotes data cache clean instructions to 315 data cache clean-and-invalidate. 316 Please note that this does not necessarily enable the workaround, 317 as it depends on the alternative framework, which will only patch 318 the kernel if an affected CPU is detected. 319 320 If unsure, say Y. 321 322config ARM64_ERRATUM_827319 323 bool "Cortex-A53: 827319: Data cache clean instructions might cause overlapping transactions to the interconnect" 324 default y 325 select ARM64_WORKAROUND_CLEAN_CACHE 326 help 327 This option adds an alternative code sequence to work around ARM 328 erratum 827319 on Cortex-A53 parts up to r0p2 with an AMBA 5 CHI 329 master interface and an L2 cache. 330 331 Under certain conditions this erratum can cause a clean line eviction 332 to occur at the same time as another transaction to the same address 333 on the AMBA 5 CHI interface, which can cause data corruption if the 334 interconnect reorders the two transactions. 335 336 The workaround promotes data cache clean instructions to 337 data cache clean-and-invalidate. 338 Please note that this does not necessarily enable the workaround, 339 as it depends on the alternative framework, which will only patch 340 the kernel if an affected CPU is detected. 341 342 If unsure, say Y. 343 344config ARM64_ERRATUM_824069 345 bool "Cortex-A53: 824069: Cache line might not be marked as clean after a CleanShared snoop" 346 default y 347 select ARM64_WORKAROUND_CLEAN_CACHE 348 help 349 This option adds an alternative code sequence to work around ARM 350 erratum 824069 on Cortex-A53 parts up to r0p2 when it is connected 351 to a coherent interconnect. 352 353 If a Cortex-A53 processor is executing a store or prefetch for 354 write instruction at the same time as a processor in another 355 cluster is executing a cache maintenance operation to the same 356 address, then this erratum might cause a clean cache line to be 357 incorrectly marked as dirty. 358 359 The workaround promotes data cache clean instructions to 360 data cache clean-and-invalidate. 361 Please note that this option does not necessarily enable the 362 workaround, as it depends on the alternative framework, which will 363 only patch the kernel if an affected CPU is detected. 364 365 If unsure, say Y. 366 367config ARM64_ERRATUM_819472 368 bool "Cortex-A53: 819472: Store exclusive instructions might cause data corruption" 369 default y 370 select ARM64_WORKAROUND_CLEAN_CACHE 371 help 372 This option adds an alternative code sequence to work around ARM 373 erratum 819472 on Cortex-A53 parts up to r0p1 with an L2 cache 374 present when it is connected to a coherent interconnect. 375 376 If the processor is executing a load and store exclusive sequence at 377 the same time as a processor in another cluster is executing a cache 378 maintenance operation to the same address, then this erratum might 379 cause data corruption. 380 381 The workaround promotes data cache clean instructions to 382 data cache clean-and-invalidate. 383 Please note that this does not necessarily enable the workaround, 384 as it depends on the alternative framework, which will only patch 385 the kernel if an affected CPU is detected. 386 387 If unsure, say Y. 388 389config ARM64_ERRATUM_832075 390 bool "Cortex-A57: 832075: possible deadlock on mixing exclusive memory accesses with device loads" 391 default y 392 help 393 This option adds an alternative code sequence to work around ARM 394 erratum 832075 on Cortex-A57 parts up to r1p2. 395 396 Affected Cortex-A57 parts might deadlock when exclusive load/store 397 instructions to Write-Back memory are mixed with Device loads. 398 399 The workaround is to promote device loads to use Load-Acquire 400 semantics. 401 Please note that this does not necessarily enable the workaround, 402 as it depends on the alternative framework, which will only patch 403 the kernel if an affected CPU is detected. 404 405 If unsure, say Y. 406 407config ARM64_ERRATUM_834220 408 bool "Cortex-A57: 834220: Stage 2 translation fault might be incorrectly reported in presence of a Stage 1 fault" 409 depends on KVM 410 default y 411 help 412 This option adds an alternative code sequence to work around ARM 413 erratum 834220 on Cortex-A57 parts up to r1p2. 414 415 Affected Cortex-A57 parts might report a Stage 2 translation 416 fault as the result of a Stage 1 fault for load crossing a 417 page boundary when there is a permission or device memory 418 alignment fault at Stage 1 and a translation fault at Stage 2. 419 420 The workaround is to verify that the Stage 1 translation 421 doesn't generate a fault before handling the Stage 2 fault. 422 Please note that this does not necessarily enable the workaround, 423 as it depends on the alternative framework, which will only patch 424 the kernel if an affected CPU is detected. 425 426 If unsure, say Y. 427 428config ARM64_ERRATUM_845719 429 bool "Cortex-A53: 845719: a load might read incorrect data" 430 depends on COMPAT 431 default y 432 help 433 This option adds an alternative code sequence to work around ARM 434 erratum 845719 on Cortex-A53 parts up to r0p4. 435 436 When running a compat (AArch32) userspace on an affected Cortex-A53 437 part, a load at EL0 from a virtual address that matches the bottom 32 438 bits of the virtual address used by a recent load at (AArch64) EL1 439 might return incorrect data. 440 441 The workaround is to write the contextidr_el1 register on exception 442 return to a 32-bit task. 443 Please note that this does not necessarily enable the workaround, 444 as it depends on the alternative framework, which will only patch 445 the kernel if an affected CPU is detected. 446 447 If unsure, say Y. 448 449config ARM64_ERRATUM_843419 450 bool "Cortex-A53: 843419: A load or store might access an incorrect address" 451 default y 452 select ARM64_MODULE_PLTS if MODULES 453 help 454 This option links the kernel with '--fix-cortex-a53-843419' and 455 enables PLT support to replace certain ADRP instructions, which can 456 cause subsequent memory accesses to use an incorrect address on 457 Cortex-A53 parts up to r0p4. 458 459 If unsure, say Y. 460 461config ARM64_ERRATUM_1024718 462 bool "Cortex-A55: 1024718: Update of DBM/AP bits without break before make might result in incorrect update" 463 default y 464 help 465 This option adds a workaround for ARM Cortex-A55 Erratum 1024718. 466 467 Affected Cortex-A55 cores (r0p0, r0p1, r1p0) could cause incorrect 468 update of the hardware dirty bit when the DBM/AP bits are updated 469 without a break-before-make. The workaround is to disable the usage 470 of hardware DBM locally on the affected cores. CPUs not affected by 471 this erratum will continue to use the feature. 472 473 If unsure, say Y. 474 475config ARM64_ERRATUM_1188873 476 bool "Cortex-A76/Neoverse-N1: MRC read following MRRC read of specific Generic Timer in AArch32 might give incorrect result" 477 default y 478 depends on COMPAT 479 select ARM_ARCH_TIMER_OOL_WORKAROUND 480 help 481 This option adds a workaround for ARM Cortex-A76/Neoverse-N1 482 erratum 1188873. 483 484 Affected Cortex-A76/Neoverse-N1 cores (r0p0, r1p0, r2p0) could 485 cause register corruption when accessing the timer registers 486 from AArch32 userspace. 487 488 If unsure, say Y. 489 490config ARM64_ERRATUM_1165522 491 bool "Cortex-A76: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation" 492 default y 493 help 494 This option adds a workaround for ARM Cortex-A76 erratum 1165522. 495 496 Affected Cortex-A76 cores (r0p0, r1p0, r2p0) could end-up with 497 corrupted TLBs by speculating an AT instruction during a guest 498 context switch. 499 500 If unsure, say Y. 501 502config ARM64_ERRATUM_1286807 503 bool "Cortex-A76: Modification of the translation table for a virtual address might lead to read-after-read ordering violation" 504 default y 505 select ARM64_WORKAROUND_REPEAT_TLBI 506 help 507 This option adds a workaround for ARM Cortex-A76 erratum 1286807. 508 509 On the affected Cortex-A76 cores (r0p0 to r3p0), if a virtual 510 address for a cacheable mapping of a location is being 511 accessed by a core while another core is remapping the virtual 512 address to a new physical page using the recommended 513 break-before-make sequence, then under very rare circumstances 514 TLBI+DSB completes before a read using the translation being 515 invalidated has been observed by other observers. The 516 workaround repeats the TLBI+DSB operation. 517 518 If unsure, say Y. 519 520config CAVIUM_ERRATUM_22375 521 bool "Cavium erratum 22375, 24313" 522 default y 523 help 524 Enable workaround for errata 22375 and 24313. 525 526 This implements two gicv3-its errata workarounds for ThunderX. Both 527 with a small impact affecting only ITS table allocation. 528 529 erratum 22375: only alloc 8MB table size 530 erratum 24313: ignore memory access type 531 532 The fixes are in ITS initialization and basically ignore memory access 533 type and table size provided by the TYPER and BASER registers. 534 535 If unsure, say Y. 536 537config CAVIUM_ERRATUM_23144 538 bool "Cavium erratum 23144: ITS SYNC hang on dual socket system" 539 depends on NUMA 540 default y 541 help 542 ITS SYNC command hang for cross node io and collections/cpu mapping. 543 544 If unsure, say Y. 545 546config CAVIUM_ERRATUM_23154 547 bool "Cavium erratum 23154: Access to ICC_IAR1_EL1 is not sync'ed" 548 default y 549 help 550 The gicv3 of ThunderX requires a modified version for 551 reading the IAR status to ensure data synchronization 552 (access to icc_iar1_el1 is not sync'ed before and after). 553 554 If unsure, say Y. 555 556config CAVIUM_ERRATUM_27456 557 bool "Cavium erratum 27456: Broadcast TLBI instructions may cause icache corruption" 558 default y 559 help 560 On ThunderX T88 pass 1.x through 2.1 parts, broadcast TLBI 561 instructions may cause the icache to become corrupted if it 562 contains data for a non-current ASID. The fix is to 563 invalidate the icache when changing the mm context. 564 565 If unsure, say Y. 566 567config CAVIUM_ERRATUM_30115 568 bool "Cavium erratum 30115: Guest may disable interrupts in host" 569 default y 570 help 571 On ThunderX T88 pass 1.x through 2.2, T81 pass 1.0 through 572 1.2, and T83 Pass 1.0, KVM guest execution may disable 573 interrupts in host. Trapping both GICv3 group-0 and group-1 574 accesses sidesteps the issue. 575 576 If unsure, say Y. 577 578config QCOM_FALKOR_ERRATUM_1003 579 bool "Falkor E1003: Incorrect translation due to ASID change" 580 default y 581 help 582 On Falkor v1, an incorrect ASID may be cached in the TLB when ASID 583 and BADDR are changed together in TTBRx_EL1. Since we keep the ASID 584 in TTBR1_EL1, this situation only occurs in the entry trampoline and 585 then only for entries in the walk cache, since the leaf translation 586 is unchanged. Work around the erratum by invalidating the walk cache 587 entries for the trampoline before entering the kernel proper. 588 589config ARM64_WORKAROUND_REPEAT_TLBI 590 bool 591 592config QCOM_FALKOR_ERRATUM_1009 593 bool "Falkor E1009: Prematurely complete a DSB after a TLBI" 594 default y 595 select ARM64_WORKAROUND_REPEAT_TLBI 596 help 597 On Falkor v1, the CPU may prematurely complete a DSB following a 598 TLBI xxIS invalidate maintenance operation. Repeat the TLBI operation 599 one more time to fix the issue. 600 601 If unsure, say Y. 602 603config QCOM_QDF2400_ERRATUM_0065 604 bool "QDF2400 E0065: Incorrect GITS_TYPER.ITT_Entry_size" 605 default y 606 help 607 On Qualcomm Datacenter Technologies QDF2400 SoC, ITS hardware reports 608 ITE size incorrectly. The GITS_TYPER.ITT_Entry_size field should have 609 been indicated as 16Bytes (0xf), not 8Bytes (0x7). 610 611 If unsure, say Y. 612 613config SOCIONEXT_SYNQUACER_PREITS 614 bool "Socionext Synquacer: Workaround for GICv3 pre-ITS" 615 default y 616 help 617 Socionext Synquacer SoCs implement a separate h/w block to generate 618 MSI doorbell writes with non-zero values for the device ID. 619 620 If unsure, say Y. 621 622config HISILICON_ERRATUM_161600802 623 bool "Hip07 161600802: Erroneous redistributor VLPI base" 624 default y 625 help 626 The HiSilicon Hip07 SoC uses the wrong redistributor base 627 when issued ITS commands such as VMOVP and VMAPP, and requires 628 a 128kB offset to be applied to the target address in this commands. 629 630 If unsure, say Y. 631 632config QCOM_FALKOR_ERRATUM_E1041 633 bool "Falkor E1041: Speculative instruction fetches might cause errant memory access" 634 default y 635 help 636 Falkor CPU may speculatively fetch instructions from an improper 637 memory location when MMU translation is changed from SCTLR_ELn[M]=1 638 to SCTLR_ELn[M]=0. Prefix an ISB instruction to fix the problem. 639 640 If unsure, say Y. 641 642config FUJITSU_ERRATUM_010001 643 bool "Fujitsu-A64FX erratum E#010001: Undefined fault may occur wrongly" 644 default y 645 help 646 This option adds a workaround for Fujitsu-A64FX erratum E#010001. 647 On some variants of the Fujitsu-A64FX cores ver(1.0, 1.1), memory 648 accesses may cause undefined fault (Data abort, DFSC=0b111111). 649 This fault occurs under a specific hardware condition when a 650 load/store instruction performs an address translation using: 651 case-1 TTBR0_EL1 with TCR_EL1.NFD0 == 1. 652 case-2 TTBR0_EL2 with TCR_EL2.NFD0 == 1. 653 case-3 TTBR1_EL1 with TCR_EL1.NFD1 == 1. 654 case-4 TTBR1_EL2 with TCR_EL2.NFD1 == 1. 655 656 The workaround is to ensure these bits are clear in TCR_ELx. 657 The workaround only affects the Fujitsu-A64FX. 658 659 If unsure, say Y. 660 661endmenu 662 663 664choice 665 prompt "Page size" 666 default ARM64_4K_PAGES 667 help 668 Page size (translation granule) configuration. 669 670config ARM64_4K_PAGES 671 bool "4KB" 672 help 673 This feature enables 4KB pages support. 674 675config ARM64_16K_PAGES 676 bool "16KB" 677 help 678 The system will use 16KB pages support. AArch32 emulation 679 requires applications compiled with 16K (or a multiple of 16K) 680 aligned segments. 681 682config ARM64_64K_PAGES 683 bool "64KB" 684 help 685 This feature enables 64KB pages support (4KB by default) 686 allowing only two levels of page tables and faster TLB 687 look-up. AArch32 emulation requires applications compiled 688 with 64K aligned segments. 689 690endchoice 691 692choice 693 prompt "Virtual address space size" 694 default ARM64_VA_BITS_39 if ARM64_4K_PAGES 695 default ARM64_VA_BITS_47 if ARM64_16K_PAGES 696 default ARM64_VA_BITS_42 if ARM64_64K_PAGES 697 help 698 Allows choosing one of multiple possible virtual address 699 space sizes. The level of translation table is determined by 700 a combination of page size and virtual address space size. 701 702config ARM64_VA_BITS_36 703 bool "36-bit" if EXPERT 704 depends on ARM64_16K_PAGES 705 706config ARM64_VA_BITS_39 707 bool "39-bit" 708 depends on ARM64_4K_PAGES 709 710config ARM64_VA_BITS_42 711 bool "42-bit" 712 depends on ARM64_64K_PAGES 713 714config ARM64_VA_BITS_47 715 bool "47-bit" 716 depends on ARM64_16K_PAGES 717 718config ARM64_VA_BITS_48 719 bool "48-bit" 720 721config ARM64_USER_VA_BITS_52 722 bool "52-bit (user)" 723 depends on ARM64_64K_PAGES && (ARM64_PAN || !ARM64_SW_TTBR0_PAN) 724 help 725 Enable 52-bit virtual addressing for userspace when explicitly 726 requested via a hint to mmap(). The kernel will continue to 727 use 48-bit virtual addresses for its own mappings. 728 729 NOTE: Enabling 52-bit virtual addressing in conjunction with 730 ARMv8.3 Pointer Authentication will result in the PAC being 731 reduced from 7 bits to 3 bits, which may have a significant 732 impact on its susceptibility to brute-force attacks. 733 734 If unsure, select 48-bit virtual addressing instead. 735 736endchoice 737 738config ARM64_FORCE_52BIT 739 bool "Force 52-bit virtual addresses for userspace" 740 depends on ARM64_USER_VA_BITS_52 && EXPERT 741 help 742 For systems with 52-bit userspace VAs enabled, the kernel will attempt 743 to maintain compatibility with older software by providing 48-bit VAs 744 unless a hint is supplied to mmap. 745 746 This configuration option disables the 48-bit compatibility logic, and 747 forces all userspace addresses to be 52-bit on HW that supports it. One 748 should only enable this configuration option for stress testing userspace 749 memory management code. If unsure say N here. 750 751config ARM64_VA_BITS 752 int 753 default 36 if ARM64_VA_BITS_36 754 default 39 if ARM64_VA_BITS_39 755 default 42 if ARM64_VA_BITS_42 756 default 47 if ARM64_VA_BITS_47 757 default 48 if ARM64_VA_BITS_48 || ARM64_USER_VA_BITS_52 758 759choice 760 prompt "Physical address space size" 761 default ARM64_PA_BITS_48 762 help 763 Choose the maximum physical address range that the kernel will 764 support. 765 766config ARM64_PA_BITS_48 767 bool "48-bit" 768 769config ARM64_PA_BITS_52 770 bool "52-bit (ARMv8.2)" 771 depends on ARM64_64K_PAGES 772 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN 773 help 774 Enable support for a 52-bit physical address space, introduced as 775 part of the ARMv8.2-LPA extension. 776 777 With this enabled, the kernel will also continue to work on CPUs that 778 do not support ARMv8.2-LPA, but with some added memory overhead (and 779 minor performance overhead). 780 781endchoice 782 783config ARM64_PA_BITS 784 int 785 default 48 if ARM64_PA_BITS_48 786 default 52 if ARM64_PA_BITS_52 787 788config CPU_BIG_ENDIAN 789 bool "Build big-endian kernel" 790 help 791 Say Y if you plan on running a kernel in big-endian mode. 792 793config SCHED_MC 794 bool "Multi-core scheduler support" 795 help 796 Multi-core scheduler support improves the CPU scheduler's decision 797 making when dealing with multi-core CPU chips at a cost of slightly 798 increased overhead in some places. If unsure say N here. 799 800config SCHED_SMT 801 bool "SMT scheduler support" 802 help 803 Improves the CPU scheduler's decision making when dealing with 804 MultiThreading at a cost of slightly increased overhead in some 805 places. If unsure say N here. 806 807config NR_CPUS 808 int "Maximum number of CPUs (2-4096)" 809 range 2 4096 810 default "256" 811 812config HOTPLUG_CPU 813 bool "Support for hot-pluggable CPUs" 814 select GENERIC_IRQ_MIGRATION 815 help 816 Say Y here to experiment with turning CPUs off and on. CPUs 817 can be controlled through /sys/devices/system/cpu. 818 819# Common NUMA Features 820config NUMA 821 bool "Numa Memory Allocation and Scheduler Support" 822 select ACPI_NUMA if ACPI 823 select OF_NUMA 824 help 825 Enable NUMA (Non Uniform Memory Access) support. 826 827 The kernel will try to allocate memory used by a CPU on the 828 local memory of the CPU and add some more 829 NUMA awareness to the kernel. 830 831config NODES_SHIFT 832 int "Maximum NUMA Nodes (as a power of 2)" 833 range 1 10 834 default "2" 835 depends on NEED_MULTIPLE_NODES 836 help 837 Specify the maximum number of NUMA Nodes available on the target 838 system. Increases memory reserved to accommodate various tables. 839 840config USE_PERCPU_NUMA_NODE_ID 841 def_bool y 842 depends on NUMA 843 844config HAVE_SETUP_PER_CPU_AREA 845 def_bool y 846 depends on NUMA 847 848config NEED_PER_CPU_EMBED_FIRST_CHUNK 849 def_bool y 850 depends on NUMA 851 852config HOLES_IN_ZONE 853 def_bool y 854 855source "kernel/Kconfig.hz" 856 857config ARCH_SUPPORTS_DEBUG_PAGEALLOC 858 def_bool y 859 860config ARCH_SPARSEMEM_ENABLE 861 def_bool y 862 select SPARSEMEM_VMEMMAP_ENABLE 863 864config ARCH_SPARSEMEM_DEFAULT 865 def_bool ARCH_SPARSEMEM_ENABLE 866 867config ARCH_SELECT_MEMORY_MODEL 868 def_bool ARCH_SPARSEMEM_ENABLE 869 870config ARCH_FLATMEM_ENABLE 871 def_bool !NUMA 872 873config HAVE_ARCH_PFN_VALID 874 def_bool y 875 876config HW_PERF_EVENTS 877 def_bool y 878 depends on ARM_PMU 879 880config SYS_SUPPORTS_HUGETLBFS 881 def_bool y 882 883config ARCH_WANT_HUGE_PMD_SHARE 884 def_bool y if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36) 885 886config ARCH_HAS_CACHE_LINE_SIZE 887 def_bool y 888 889config ARCH_ENABLE_SPLIT_PMD_PTLOCK 890 def_bool y if PGTABLE_LEVELS > 2 891 892config SECCOMP 893 bool "Enable seccomp to safely compute untrusted bytecode" 894 ---help--- 895 This kernel feature is useful for number crunching applications 896 that may need to compute untrusted bytecode during their 897 execution. By using pipes or other transports made available to 898 the process as file descriptors supporting the read/write 899 syscalls, it's possible to isolate those applications in 900 their own address space using seccomp. Once seccomp is 901 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 902 and the task is only allowed to execute a few safe syscalls 903 defined by each seccomp mode. 904 905config PARAVIRT 906 bool "Enable paravirtualization code" 907 help 908 This changes the kernel so it can modify itself when it is run 909 under a hypervisor, potentially improving performance significantly 910 over full virtualization. 911 912config PARAVIRT_TIME_ACCOUNTING 913 bool "Paravirtual steal time accounting" 914 select PARAVIRT 915 default n 916 help 917 Select this option to enable fine granularity task steal time 918 accounting. Time spent executing other tasks in parallel with 919 the current vCPU is discounted from the vCPU power. To account for 920 that, there can be a small performance impact. 921 922 If in doubt, say N here. 923 924config KEXEC 925 depends on PM_SLEEP_SMP 926 select KEXEC_CORE 927 bool "kexec system call" 928 ---help--- 929 kexec is a system call that implements the ability to shutdown your 930 current kernel, and to start another kernel. It is like a reboot 931 but it is independent of the system firmware. And like a reboot 932 you can start any kernel with it, not just Linux. 933 934config KEXEC_FILE 935 bool "kexec file based system call" 936 select KEXEC_CORE 937 help 938 This is new version of kexec system call. This system call is 939 file based and takes file descriptors as system call argument 940 for kernel and initramfs as opposed to list of segments as 941 accepted by previous system call. 942 943config KEXEC_VERIFY_SIG 944 bool "Verify kernel signature during kexec_file_load() syscall" 945 depends on KEXEC_FILE 946 help 947 Select this option to verify a signature with loaded kernel 948 image. If configured, any attempt of loading a image without 949 valid signature will fail. 950 951 In addition to that option, you need to enable signature 952 verification for the corresponding kernel image type being 953 loaded in order for this to work. 954 955config KEXEC_IMAGE_VERIFY_SIG 956 bool "Enable Image signature verification support" 957 default y 958 depends on KEXEC_VERIFY_SIG 959 depends on EFI && SIGNED_PE_FILE_VERIFICATION 960 help 961 Enable Image signature verification support. 962 963comment "Support for PE file signature verification disabled" 964 depends on KEXEC_VERIFY_SIG 965 depends on !EFI || !SIGNED_PE_FILE_VERIFICATION 966 967config CRASH_DUMP 968 bool "Build kdump crash kernel" 969 help 970 Generate crash dump after being started by kexec. This should 971 be normally only set in special crash dump kernels which are 972 loaded in the main kernel with kexec-tools into a specially 973 reserved region and then later executed after a crash by 974 kdump/kexec. 975 976 For more details see Documentation/kdump/kdump.txt 977 978config XEN_DOM0 979 def_bool y 980 depends on XEN 981 982config XEN 983 bool "Xen guest support on ARM64" 984 depends on ARM64 && OF 985 select SWIOTLB_XEN 986 select PARAVIRT 987 help 988 Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64. 989 990config FORCE_MAX_ZONEORDER 991 int 992 default "14" if (ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE) 993 default "12" if (ARM64_16K_PAGES && TRANSPARENT_HUGEPAGE) 994 default "11" 995 help 996 The kernel memory allocator divides physically contiguous memory 997 blocks into "zones", where each zone is a power of two number of 998 pages. This option selects the largest power of two that the kernel 999 keeps in the memory allocator. If you need to allocate very large 1000 blocks of physically contiguous memory, then you may need to 1001 increase this value. 1002 1003 This config option is actually maximum order plus one. For example, 1004 a value of 11 means that the largest free memory block is 2^10 pages. 1005 1006 We make sure that we can allocate upto a HugePage size for each configuration. 1007 Hence we have : 1008 MAX_ORDER = (PMD_SHIFT - PAGE_SHIFT) + 1 => PAGE_SHIFT - 2 1009 1010 However for 4K, we choose a higher default value, 11 as opposed to 10, giving us 1011 4M allocations matching the default size used by generic code. 1012 1013config UNMAP_KERNEL_AT_EL0 1014 bool "Unmap kernel when running in userspace (aka \"KAISER\")" if EXPERT 1015 default y 1016 help 1017 Speculation attacks against some high-performance processors can 1018 be used to bypass MMU permission checks and leak kernel data to 1019 userspace. This can be defended against by unmapping the kernel 1020 when running in userspace, mapping it back in on exception entry 1021 via a trampoline page in the vector table. 1022 1023 If unsure, say Y. 1024 1025config HARDEN_BRANCH_PREDICTOR 1026 bool "Harden the branch predictor against aliasing attacks" if EXPERT 1027 default y 1028 help 1029 Speculation attacks against some high-performance processors rely on 1030 being able to manipulate the branch predictor for a victim context by 1031 executing aliasing branches in the attacker context. Such attacks 1032 can be partially mitigated against by clearing internal branch 1033 predictor state and limiting the prediction logic in some situations. 1034 1035 This config option will take CPU-specific actions to harden the 1036 branch predictor against aliasing attacks and may rely on specific 1037 instruction sequences or control bits being set by the system 1038 firmware. 1039 1040 If unsure, say Y. 1041 1042config HARDEN_EL2_VECTORS 1043 bool "Harden EL2 vector mapping against system register leak" if EXPERT 1044 default y 1045 help 1046 Speculation attacks against some high-performance processors can 1047 be used to leak privileged information such as the vector base 1048 register, resulting in a potential defeat of the EL2 layout 1049 randomization. 1050 1051 This config option will map the vectors to a fixed location, 1052 independent of the EL2 code mapping, so that revealing VBAR_EL2 1053 to an attacker does not give away any extra information. This 1054 only gets enabled on affected CPUs. 1055 1056 If unsure, say Y. 1057 1058config ARM64_SSBD 1059 bool "Speculative Store Bypass Disable" if EXPERT 1060 default y 1061 help 1062 This enables mitigation of the bypassing of previous stores 1063 by speculative loads. 1064 1065 If unsure, say Y. 1066 1067config RODATA_FULL_DEFAULT_ENABLED 1068 bool "Apply r/o permissions of VM areas also to their linear aliases" 1069 default y 1070 help 1071 Apply read-only attributes of VM areas to the linear alias of 1072 the backing pages as well. This prevents code or read-only data 1073 from being modified (inadvertently or intentionally) via another 1074 mapping of the same memory page. This additional enhancement can 1075 be turned off at runtime by passing rodata=[off|on] (and turned on 1076 with rodata=full if this option is set to 'n') 1077 1078 This requires the linear region to be mapped down to pages, 1079 which may adversely affect performance in some cases. 1080 1081config ARM64_SW_TTBR0_PAN 1082 bool "Emulate Privileged Access Never using TTBR0_EL1 switching" 1083 help 1084 Enabling this option prevents the kernel from accessing 1085 user-space memory directly by pointing TTBR0_EL1 to a reserved 1086 zeroed area and reserved ASID. The user access routines 1087 restore the valid TTBR0_EL1 temporarily. 1088 1089menuconfig COMPAT 1090 bool "Kernel support for 32-bit EL0" 1091 depends on ARM64_4K_PAGES || EXPERT 1092 select COMPAT_BINFMT_ELF if BINFMT_ELF 1093 select HAVE_UID16 1094 select OLD_SIGSUSPEND3 1095 select COMPAT_OLD_SIGACTION 1096 help 1097 This option enables support for a 32-bit EL0 running under a 64-bit 1098 kernel at EL1. AArch32-specific components such as system calls, 1099 the user helper functions, VFP support and the ptrace interface are 1100 handled appropriately by the kernel. 1101 1102 If you use a page size other than 4KB (i.e, 16KB or 64KB), please be aware 1103 that you will only be able to execute AArch32 binaries that were compiled 1104 with page size aligned segments. 1105 1106 If you want to execute 32-bit userspace applications, say Y. 1107 1108if COMPAT 1109 1110config KUSER_HELPERS 1111 bool "Enable kuser helpers page for 32 bit applications" 1112 default y 1113 help 1114 Warning: disabling this option may break 32-bit user programs. 1115 1116 Provide kuser helpers to compat tasks. The kernel provides 1117 helper code to userspace in read only form at a fixed location 1118 to allow userspace to be independent of the CPU type fitted to 1119 the system. This permits binaries to be run on ARMv4 through 1120 to ARMv8 without modification. 1121 1122 See Documentation/arm/kernel_user_helpers.txt for details. 1123 1124 However, the fixed address nature of these helpers can be used 1125 by ROP (return orientated programming) authors when creating 1126 exploits. 1127 1128 If all of the binaries and libraries which run on your platform 1129 are built specifically for your platform, and make no use of 1130 these helpers, then you can turn this option off to hinder 1131 such exploits. However, in that case, if a binary or library 1132 relying on those helpers is run, it will not function correctly. 1133 1134 Say N here only if you are absolutely certain that you do not 1135 need these helpers; otherwise, the safe option is to say Y. 1136 1137 1138menuconfig ARMV8_DEPRECATED 1139 bool "Emulate deprecated/obsolete ARMv8 instructions" 1140 depends on SYSCTL 1141 help 1142 Legacy software support may require certain instructions 1143 that have been deprecated or obsoleted in the architecture. 1144 1145 Enable this config to enable selective emulation of these 1146 features. 1147 1148 If unsure, say Y 1149 1150if ARMV8_DEPRECATED 1151 1152config SWP_EMULATION 1153 bool "Emulate SWP/SWPB instructions" 1154 help 1155 ARMv8 obsoletes the use of A32 SWP/SWPB instructions such that 1156 they are always undefined. Say Y here to enable software 1157 emulation of these instructions for userspace using LDXR/STXR. 1158 1159 In some older versions of glibc [<=2.8] SWP is used during futex 1160 trylock() operations with the assumption that the code will not 1161 be preempted. This invalid assumption may be more likely to fail 1162 with SWP emulation enabled, leading to deadlock of the user 1163 application. 1164 1165 NOTE: when accessing uncached shared regions, LDXR/STXR rely 1166 on an external transaction monitoring block called a global 1167 monitor to maintain update atomicity. If your system does not 1168 implement a global monitor, this option can cause programs that 1169 perform SWP operations to uncached memory to deadlock. 1170 1171 If unsure, say Y 1172 1173config CP15_BARRIER_EMULATION 1174 bool "Emulate CP15 Barrier instructions" 1175 help 1176 The CP15 barrier instructions - CP15ISB, CP15DSB, and 1177 CP15DMB - are deprecated in ARMv8 (and ARMv7). It is 1178 strongly recommended to use the ISB, DSB, and DMB 1179 instructions instead. 1180 1181 Say Y here to enable software emulation of these 1182 instructions for AArch32 userspace code. When this option is 1183 enabled, CP15 barrier usage is traced which can help 1184 identify software that needs updating. 1185 1186 If unsure, say Y 1187 1188config SETEND_EMULATION 1189 bool "Emulate SETEND instruction" 1190 help 1191 The SETEND instruction alters the data-endianness of the 1192 AArch32 EL0, and is deprecated in ARMv8. 1193 1194 Say Y here to enable software emulation of the instruction 1195 for AArch32 userspace code. 1196 1197 Note: All the cpus on the system must have mixed endian support at EL0 1198 for this feature to be enabled. If a new CPU - which doesn't support mixed 1199 endian - is hotplugged in after this feature has been enabled, there could 1200 be unexpected results in the applications. 1201 1202 If unsure, say Y 1203endif 1204 1205endif 1206 1207menu "ARMv8.1 architectural features" 1208 1209config ARM64_HW_AFDBM 1210 bool "Support for hardware updates of the Access and Dirty page flags" 1211 default y 1212 help 1213 The ARMv8.1 architecture extensions introduce support for 1214 hardware updates of the access and dirty information in page 1215 table entries. When enabled in TCR_EL1 (HA and HD bits) on 1216 capable processors, accesses to pages with PTE_AF cleared will 1217 set this bit instead of raising an access flag fault. 1218 Similarly, writes to read-only pages with the DBM bit set will 1219 clear the read-only bit (AP[2]) instead of raising a 1220 permission fault. 1221 1222 Kernels built with this configuration option enabled continue 1223 to work on pre-ARMv8.1 hardware and the performance impact is 1224 minimal. If unsure, say Y. 1225 1226config ARM64_PAN 1227 bool "Enable support for Privileged Access Never (PAN)" 1228 default y 1229 help 1230 Privileged Access Never (PAN; part of the ARMv8.1 Extensions) 1231 prevents the kernel or hypervisor from accessing user-space (EL0) 1232 memory directly. 1233 1234 Choosing this option will cause any unprotected (not using 1235 copy_to_user et al) memory access to fail with a permission fault. 1236 1237 The feature is detected at runtime, and will remain as a 'nop' 1238 instruction if the cpu does not implement the feature. 1239 1240config ARM64_LSE_ATOMICS 1241 bool "Atomic instructions" 1242 default y 1243 help 1244 As part of the Large System Extensions, ARMv8.1 introduces new 1245 atomic instructions that are designed specifically to scale in 1246 very large systems. 1247 1248 Say Y here to make use of these instructions for the in-kernel 1249 atomic routines. This incurs a small overhead on CPUs that do 1250 not support these instructions and requires the kernel to be 1251 built with binutils >= 2.25 in order for the new instructions 1252 to be used. 1253 1254config ARM64_VHE 1255 bool "Enable support for Virtualization Host Extensions (VHE)" 1256 default y 1257 help 1258 Virtualization Host Extensions (VHE) allow the kernel to run 1259 directly at EL2 (instead of EL1) on processors that support 1260 it. This leads to better performance for KVM, as they reduce 1261 the cost of the world switch. 1262 1263 Selecting this option allows the VHE feature to be detected 1264 at runtime, and does not affect processors that do not 1265 implement this feature. 1266 1267endmenu 1268 1269menu "ARMv8.2 architectural features" 1270 1271config ARM64_UAO 1272 bool "Enable support for User Access Override (UAO)" 1273 default y 1274 help 1275 User Access Override (UAO; part of the ARMv8.2 Extensions) 1276 causes the 'unprivileged' variant of the load/store instructions to 1277 be overridden to be privileged. 1278 1279 This option changes get_user() and friends to use the 'unprivileged' 1280 variant of the load/store instructions. This ensures that user-space 1281 really did have access to the supplied memory. When addr_limit is 1282 set to kernel memory the UAO bit will be set, allowing privileged 1283 access to kernel memory. 1284 1285 Choosing this option will cause copy_to_user() et al to use user-space 1286 memory permissions. 1287 1288 The feature is detected at runtime, the kernel will use the 1289 regular load/store instructions if the cpu does not implement the 1290 feature. 1291 1292config ARM64_PMEM 1293 bool "Enable support for persistent memory" 1294 select ARCH_HAS_PMEM_API 1295 select ARCH_HAS_UACCESS_FLUSHCACHE 1296 help 1297 Say Y to enable support for the persistent memory API based on the 1298 ARMv8.2 DCPoP feature. 1299 1300 The feature is detected at runtime, and the kernel will use DC CVAC 1301 operations if DC CVAP is not supported (following the behaviour of 1302 DC CVAP itself if the system does not define a point of persistence). 1303 1304config ARM64_RAS_EXTN 1305 bool "Enable support for RAS CPU Extensions" 1306 default y 1307 help 1308 CPUs that support the Reliability, Availability and Serviceability 1309 (RAS) Extensions, part of ARMv8.2 are able to track faults and 1310 errors, classify them and report them to software. 1311 1312 On CPUs with these extensions system software can use additional 1313 barriers to determine if faults are pending and read the 1314 classification from a new set of registers. 1315 1316 Selecting this feature will allow the kernel to use these barriers 1317 and access the new registers if the system supports the extension. 1318 Platform RAS features may additionally depend on firmware support. 1319 1320config ARM64_CNP 1321 bool "Enable support for Common Not Private (CNP) translations" 1322 default y 1323 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN 1324 help 1325 Common Not Private (CNP) allows translation table entries to 1326 be shared between different PEs in the same inner shareable 1327 domain, so the hardware can use this fact to optimise the 1328 caching of such entries in the TLB. 1329 1330 Selecting this option allows the CNP feature to be detected 1331 at runtime, and does not affect PEs that do not implement 1332 this feature. 1333 1334endmenu 1335 1336menu "ARMv8.3 architectural features" 1337 1338config ARM64_PTR_AUTH 1339 bool "Enable support for pointer authentication" 1340 default y 1341 help 1342 Pointer authentication (part of the ARMv8.3 Extensions) provides 1343 instructions for signing and authenticating pointers against secret 1344 keys, which can be used to mitigate Return Oriented Programming (ROP) 1345 and other attacks. 1346 1347 This option enables these instructions at EL0 (i.e. for userspace). 1348 1349 Choosing this option will cause the kernel to initialise secret keys 1350 for each process at exec() time, with these keys being 1351 context-switched along with the process. 1352 1353 The feature is detected at runtime. If the feature is not present in 1354 hardware it will not be advertised to userspace nor will it be 1355 enabled. 1356 1357endmenu 1358 1359config ARM64_SVE 1360 bool "ARM Scalable Vector Extension support" 1361 default y 1362 depends on !KVM || ARM64_VHE 1363 help 1364 The Scalable Vector Extension (SVE) is an extension to the AArch64 1365 execution state which complements and extends the SIMD functionality 1366 of the base architecture to support much larger vectors and to enable 1367 additional vectorisation opportunities. 1368 1369 To enable use of this extension on CPUs that implement it, say Y. 1370 1371 On CPUs that support the SVE2 extensions, this option will enable 1372 those too. 1373 1374 Note that for architectural reasons, firmware _must_ implement SVE 1375 support when running on SVE capable hardware. The required support 1376 is present in: 1377 1378 * version 1.5 and later of the ARM Trusted Firmware 1379 * the AArch64 boot wrapper since commit 5e1261e08abf 1380 ("bootwrapper: SVE: Enable SVE for EL2 and below"). 1381 1382 For other firmware implementations, consult the firmware documentation 1383 or vendor. 1384 1385 If you need the kernel to boot on SVE-capable hardware with broken 1386 firmware, you may need to say N here until you get your firmware 1387 fixed. Otherwise, you may experience firmware panics or lockups when 1388 booting the kernel. If unsure and you are not observing these 1389 symptoms, you should assume that it is safe to say Y. 1390 1391 CPUs that support SVE are architecturally required to support the 1392 Virtualization Host Extensions (VHE), so the kernel makes no 1393 provision for supporting SVE alongside KVM without VHE enabled. 1394 Thus, you will need to enable CONFIG_ARM64_VHE if you want to support 1395 KVM in the same kernel image. 1396 1397config ARM64_MODULE_PLTS 1398 bool 1399 select HAVE_MOD_ARCH_SPECIFIC 1400 1401config ARM64_PSEUDO_NMI 1402 bool "Support for NMI-like interrupts" 1403 select CONFIG_ARM_GIC_V3 1404 help 1405 Adds support for mimicking Non-Maskable Interrupts through the use of 1406 GIC interrupt priority. This support requires version 3 or later of 1407 ARM GIC. 1408 1409 This high priority configuration for interrupts needs to be 1410 explicitly enabled by setting the kernel parameter 1411 "irqchip.gicv3_pseudo_nmi" to 1. 1412 1413 If unsure, say N 1414 1415config RELOCATABLE 1416 bool 1417 help 1418 This builds the kernel as a Position Independent Executable (PIE), 1419 which retains all relocation metadata required to relocate the 1420 kernel binary at runtime to a different virtual address than the 1421 address it was linked at. 1422 Since AArch64 uses the RELA relocation format, this requires a 1423 relocation pass at runtime even if the kernel is loaded at the 1424 same address it was linked at. 1425 1426config RANDOMIZE_BASE 1427 bool "Randomize the address of the kernel image" 1428 select ARM64_MODULE_PLTS if MODULES 1429 select RELOCATABLE 1430 help 1431 Randomizes the virtual address at which the kernel image is 1432 loaded, as a security feature that deters exploit attempts 1433 relying on knowledge of the location of kernel internals. 1434 1435 It is the bootloader's job to provide entropy, by passing a 1436 random u64 value in /chosen/kaslr-seed at kernel entry. 1437 1438 When booting via the UEFI stub, it will invoke the firmware's 1439 EFI_RNG_PROTOCOL implementation (if available) to supply entropy 1440 to the kernel proper. In addition, it will randomise the physical 1441 location of the kernel Image as well. 1442 1443 If unsure, say N. 1444 1445config RANDOMIZE_MODULE_REGION_FULL 1446 bool "Randomize the module region over a 4 GB range" 1447 depends on RANDOMIZE_BASE 1448 default y 1449 help 1450 Randomizes the location of the module region inside a 4 GB window 1451 covering the core kernel. This way, it is less likely for modules 1452 to leak information about the location of core kernel data structures 1453 but it does imply that function calls between modules and the core 1454 kernel will need to be resolved via veneers in the module PLT. 1455 1456 When this option is not set, the module region will be randomized over 1457 a limited range that contains the [_stext, _etext] interval of the 1458 core kernel, so branch relocations are always in range. 1459 1460config CC_HAVE_STACKPROTECTOR_SYSREG 1461 def_bool $(cc-option,-mstack-protector-guard=sysreg -mstack-protector-guard-reg=sp_el0 -mstack-protector-guard-offset=0) 1462 1463config STACKPROTECTOR_PER_TASK 1464 def_bool y 1465 depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_SYSREG 1466 1467endmenu 1468 1469menu "Boot options" 1470 1471config ARM64_ACPI_PARKING_PROTOCOL 1472 bool "Enable support for the ARM64 ACPI parking protocol" 1473 depends on ACPI 1474 help 1475 Enable support for the ARM64 ACPI parking protocol. If disabled 1476 the kernel will not allow booting through the ARM64 ACPI parking 1477 protocol even if the corresponding data is present in the ACPI 1478 MADT table. 1479 1480config CMDLINE 1481 string "Default kernel command string" 1482 default "" 1483 help 1484 Provide a set of default command-line options at build time by 1485 entering them here. As a minimum, you should specify the the 1486 root device (e.g. root=/dev/nfs). 1487 1488config CMDLINE_FORCE 1489 bool "Always use the default kernel command string" 1490 help 1491 Always use the default kernel command string, even if the boot 1492 loader passes other arguments to the kernel. 1493 This is useful if you cannot or don't want to change the 1494 command-line options your boot loader passes to the kernel. 1495 1496config EFI_STUB 1497 bool 1498 1499config EFI 1500 bool "UEFI runtime support" 1501 depends on OF && !CPU_BIG_ENDIAN 1502 depends on KERNEL_MODE_NEON 1503 select ARCH_SUPPORTS_ACPI 1504 select LIBFDT 1505 select UCS2_STRING 1506 select EFI_PARAMS_FROM_FDT 1507 select EFI_RUNTIME_WRAPPERS 1508 select EFI_STUB 1509 select EFI_ARMSTUB 1510 default y 1511 help 1512 This option provides support for runtime services provided 1513 by UEFI firmware (such as non-volatile variables, realtime 1514 clock, and platform reset). A UEFI stub is also provided to 1515 allow the kernel to be booted as an EFI application. This 1516 is only useful on systems that have UEFI firmware. 1517 1518config DMI 1519 bool "Enable support for SMBIOS (DMI) tables" 1520 depends on EFI 1521 default y 1522 help 1523 This enables SMBIOS/DMI feature for systems. 1524 1525 This option is only useful on systems that have UEFI firmware. 1526 However, even with this option, the resultant kernel should 1527 continue to boot on existing non-UEFI platforms. 1528 1529endmenu 1530 1531config SYSVIPC_COMPAT 1532 def_bool y 1533 depends on COMPAT && SYSVIPC 1534 1535config ARCH_ENABLE_HUGEPAGE_MIGRATION 1536 def_bool y 1537 depends on HUGETLB_PAGE && MIGRATION 1538 1539menu "Power management options" 1540 1541source "kernel/power/Kconfig" 1542 1543config ARCH_HIBERNATION_POSSIBLE 1544 def_bool y 1545 depends on CPU_PM 1546 1547config ARCH_HIBERNATION_HEADER 1548 def_bool y 1549 depends on HIBERNATION 1550 1551config ARCH_SUSPEND_POSSIBLE 1552 def_bool y 1553 1554endmenu 1555 1556menu "CPU Power Management" 1557 1558source "drivers/cpuidle/Kconfig" 1559 1560source "drivers/cpufreq/Kconfig" 1561 1562endmenu 1563 1564source "drivers/firmware/Kconfig" 1565 1566source "drivers/acpi/Kconfig" 1567 1568source "arch/arm64/kvm/Kconfig" 1569 1570if CRYPTO 1571source "arch/arm64/crypto/Kconfig" 1572endif 1573