1# SPDX-License-Identifier: GPL-2.0-only 2config ARM64 3 def_bool y 4 select ACPI_CCA_REQUIRED if ACPI 5 select ACPI_GENERIC_GSI if ACPI 6 select ACPI_GTDT if ACPI 7 select ACPI_IORT if ACPI 8 select ACPI_REDUCED_HARDWARE_ONLY if ACPI 9 select ACPI_MCFG if (ACPI && PCI) 10 select ACPI_SPCR_TABLE if ACPI 11 select ACPI_PPTT if ACPI 12 select ARCH_CLOCKSOURCE_DATA 13 select ARCH_HAS_DEBUG_VIRTUAL 14 select ARCH_HAS_DEVMEM_IS_ALLOWED 15 select ARCH_HAS_DMA_COHERENT_TO_PFN 16 select ARCH_HAS_DMA_MMAP_PGPROT 17 select ARCH_HAS_DMA_PREP_COHERENT 18 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 19 select ARCH_HAS_ELF_RANDOMIZE 20 select ARCH_HAS_FAST_MULTIPLIER 21 select ARCH_HAS_FORTIFY_SOURCE 22 select ARCH_HAS_GCOV_PROFILE_ALL 23 select ARCH_HAS_GIGANTIC_PAGE 24 select ARCH_HAS_KCOV 25 select ARCH_HAS_KEEPINITRD 26 select ARCH_HAS_MEMBARRIER_SYNC_CORE 27 select ARCH_HAS_PTE_SPECIAL 28 select ARCH_HAS_SETUP_DMA_OPS 29 select ARCH_HAS_SET_MEMORY 30 select ARCH_HAS_STRICT_KERNEL_RWX 31 select ARCH_HAS_STRICT_MODULE_RWX 32 select ARCH_HAS_SYNC_DMA_FOR_DEVICE 33 select ARCH_HAS_SYNC_DMA_FOR_CPU 34 select ARCH_HAS_SYSCALL_WRAPPER 35 select ARCH_HAS_TEARDOWN_DMA_OPS if IOMMU_SUPPORT 36 select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST 37 select ARCH_HAVE_NMI_SAFE_CMPXCHG 38 select ARCH_INLINE_READ_LOCK if !PREEMPT 39 select ARCH_INLINE_READ_LOCK_BH if !PREEMPT 40 select ARCH_INLINE_READ_LOCK_IRQ if !PREEMPT 41 select ARCH_INLINE_READ_LOCK_IRQSAVE if !PREEMPT 42 select ARCH_INLINE_READ_UNLOCK if !PREEMPT 43 select ARCH_INLINE_READ_UNLOCK_BH if !PREEMPT 44 select ARCH_INLINE_READ_UNLOCK_IRQ if !PREEMPT 45 select ARCH_INLINE_READ_UNLOCK_IRQRESTORE if !PREEMPT 46 select ARCH_INLINE_WRITE_LOCK if !PREEMPT 47 select ARCH_INLINE_WRITE_LOCK_BH if !PREEMPT 48 select ARCH_INLINE_WRITE_LOCK_IRQ if !PREEMPT 49 select ARCH_INLINE_WRITE_LOCK_IRQSAVE if !PREEMPT 50 select ARCH_INLINE_WRITE_UNLOCK if !PREEMPT 51 select ARCH_INLINE_WRITE_UNLOCK_BH if !PREEMPT 52 select ARCH_INLINE_WRITE_UNLOCK_IRQ if !PREEMPT 53 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE if !PREEMPT 54 select ARCH_INLINE_SPIN_TRYLOCK if !PREEMPT 55 select ARCH_INLINE_SPIN_TRYLOCK_BH if !PREEMPT 56 select ARCH_INLINE_SPIN_LOCK if !PREEMPT 57 select ARCH_INLINE_SPIN_LOCK_BH if !PREEMPT 58 select ARCH_INLINE_SPIN_LOCK_IRQ if !PREEMPT 59 select ARCH_INLINE_SPIN_LOCK_IRQSAVE if !PREEMPT 60 select ARCH_INLINE_SPIN_UNLOCK if !PREEMPT 61 select ARCH_INLINE_SPIN_UNLOCK_BH if !PREEMPT 62 select ARCH_INLINE_SPIN_UNLOCK_IRQ if !PREEMPT 63 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPT 64 select ARCH_KEEP_MEMBLOCK 65 select ARCH_USE_CMPXCHG_LOCKREF 66 select ARCH_USE_QUEUED_RWLOCKS 67 select ARCH_USE_QUEUED_SPINLOCKS 68 select ARCH_SUPPORTS_MEMORY_FAILURE 69 select ARCH_SUPPORTS_ATOMIC_RMW 70 select ARCH_SUPPORTS_INT128 if GCC_VERSION >= 50000 || CC_IS_CLANG 71 select ARCH_SUPPORTS_NUMA_BALANCING 72 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT 73 select ARCH_WANT_FRAME_POINTERS 74 select ARCH_HAS_UBSAN_SANITIZE_ALL 75 select ARM_AMBA 76 select ARM_ARCH_TIMER 77 select ARM_GIC 78 select AUDIT_ARCH_COMPAT_GENERIC 79 select ARM_GIC_V2M if PCI 80 select ARM_GIC_V3 81 select ARM_GIC_V3_ITS if PCI 82 select ARM_PSCI_FW 83 select BUILDTIME_EXTABLE_SORT 84 select CLONE_BACKWARDS 85 select COMMON_CLK 86 select CPU_PM if (SUSPEND || CPU_IDLE) 87 select CRC32 88 select DCACHE_WORD_ACCESS 89 select DMA_DIRECT_REMAP 90 select EDAC_SUPPORT 91 select FRAME_POINTER 92 select GENERIC_ALLOCATOR 93 select GENERIC_ARCH_TOPOLOGY 94 select GENERIC_CLOCKEVENTS 95 select GENERIC_CLOCKEVENTS_BROADCAST 96 select GENERIC_CPU_AUTOPROBE 97 select GENERIC_CPU_VULNERABILITIES 98 select GENERIC_EARLY_IOREMAP 99 select GENERIC_IDLE_POLL_SETUP 100 select GENERIC_IRQ_MULTI_HANDLER 101 select GENERIC_IRQ_PROBE 102 select GENERIC_IRQ_SHOW 103 select GENERIC_IRQ_SHOW_LEVEL 104 select GENERIC_PCI_IOMAP 105 select GENERIC_SCHED_CLOCK 106 select GENERIC_SMP_IDLE_THREAD 107 select GENERIC_STRNCPY_FROM_USER 108 select GENERIC_STRNLEN_USER 109 select GENERIC_TIME_VSYSCALL 110 select HANDLE_DOMAIN_IRQ 111 select HARDIRQS_SW_RESEND 112 select HAVE_PCI 113 select HAVE_ACPI_APEI if (ACPI && EFI) 114 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 115 select HAVE_ARCH_AUDITSYSCALL 116 select HAVE_ARCH_BITREVERSE 117 select HAVE_ARCH_HUGE_VMAP 118 select HAVE_ARCH_JUMP_LABEL 119 select HAVE_ARCH_JUMP_LABEL_RELATIVE 120 select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48) 121 select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN 122 select HAVE_ARCH_KGDB 123 select HAVE_ARCH_MMAP_RND_BITS 124 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT 125 select HAVE_ARCH_PREL32_RELOCATIONS 126 select HAVE_ARCH_SECCOMP_FILTER 127 select HAVE_ARCH_STACKLEAK 128 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 129 select HAVE_ARCH_TRACEHOOK 130 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 131 select HAVE_ARCH_VMAP_STACK 132 select HAVE_ARM_SMCCC 133 select HAVE_EBPF_JIT 134 select HAVE_C_RECORDMCOUNT 135 select HAVE_CMPXCHG_DOUBLE 136 select HAVE_CMPXCHG_LOCAL 137 select HAVE_CONTEXT_TRACKING 138 select HAVE_DEBUG_BUGVERBOSE 139 select HAVE_DEBUG_KMEMLEAK 140 select HAVE_DMA_CONTIGUOUS 141 select HAVE_DYNAMIC_FTRACE 142 select HAVE_EFFICIENT_UNALIGNED_ACCESS 143 select HAVE_FTRACE_MCOUNT_RECORD 144 select HAVE_FUNCTION_TRACER 145 select HAVE_FUNCTION_GRAPH_TRACER 146 select HAVE_GCC_PLUGINS 147 select HAVE_HW_BREAKPOINT if PERF_EVENTS 148 select HAVE_IRQ_TIME_ACCOUNTING 149 select HAVE_MEMBLOCK_NODE_MAP if NUMA 150 select HAVE_NMI 151 select HAVE_PATA_PLATFORM 152 select HAVE_PERF_EVENTS 153 select HAVE_PERF_REGS 154 select HAVE_PERF_USER_STACK_DUMP 155 select HAVE_REGS_AND_STACK_ACCESS_API 156 select HAVE_FUNCTION_ARG_ACCESS_API 157 select HAVE_RCU_TABLE_FREE 158 select HAVE_RSEQ 159 select HAVE_STACKPROTECTOR 160 select HAVE_SYSCALL_TRACEPOINTS 161 select HAVE_KPROBES 162 select HAVE_KRETPROBES 163 select IOMMU_DMA if IOMMU_SUPPORT 164 select IRQ_DOMAIN 165 select IRQ_FORCED_THREADING 166 select MODULES_USE_ELF_RELA 167 select NEED_DMA_MAP_STATE 168 select NEED_SG_DMA_LENGTH 169 select OF 170 select OF_EARLY_FLATTREE 171 select PCI_DOMAINS_GENERIC if PCI 172 select PCI_ECAM if (ACPI && PCI) 173 select PCI_SYSCALL if PCI 174 select POWER_RESET 175 select POWER_SUPPLY 176 select REFCOUNT_FULL 177 select SPARSE_IRQ 178 select SWIOTLB 179 select SYSCTL_EXCEPTION_TRACE 180 select THREAD_INFO_IN_TASK 181 help 182 ARM 64-bit (AArch64) Linux support. 183 184config 64BIT 185 def_bool y 186 187config MMU 188 def_bool y 189 190config ARM64_PAGE_SHIFT 191 int 192 default 16 if ARM64_64K_PAGES 193 default 14 if ARM64_16K_PAGES 194 default 12 195 196config ARM64_CONT_SHIFT 197 int 198 default 5 if ARM64_64K_PAGES 199 default 7 if ARM64_16K_PAGES 200 default 4 201 202config ARCH_MMAP_RND_BITS_MIN 203 default 14 if ARM64_64K_PAGES 204 default 16 if ARM64_16K_PAGES 205 default 18 206 207# max bits determined by the following formula: 208# VA_BITS - PAGE_SHIFT - 3 209config ARCH_MMAP_RND_BITS_MAX 210 default 19 if ARM64_VA_BITS=36 211 default 24 if ARM64_VA_BITS=39 212 default 27 if ARM64_VA_BITS=42 213 default 30 if ARM64_VA_BITS=47 214 default 29 if ARM64_VA_BITS=48 && ARM64_64K_PAGES 215 default 31 if ARM64_VA_BITS=48 && ARM64_16K_PAGES 216 default 33 if ARM64_VA_BITS=48 217 default 14 if ARM64_64K_PAGES 218 default 16 if ARM64_16K_PAGES 219 default 18 220 221config ARCH_MMAP_RND_COMPAT_BITS_MIN 222 default 7 if ARM64_64K_PAGES 223 default 9 if ARM64_16K_PAGES 224 default 11 225 226config ARCH_MMAP_RND_COMPAT_BITS_MAX 227 default 16 228 229config NO_IOPORT_MAP 230 def_bool y if !PCI 231 232config STACKTRACE_SUPPORT 233 def_bool y 234 235config ILLEGAL_POINTER_VALUE 236 hex 237 default 0xdead000000000000 238 239config LOCKDEP_SUPPORT 240 def_bool y 241 242config TRACE_IRQFLAGS_SUPPORT 243 def_bool y 244 245config GENERIC_BUG 246 def_bool y 247 depends on BUG 248 249config GENERIC_BUG_RELATIVE_POINTERS 250 def_bool y 251 depends on GENERIC_BUG 252 253config GENERIC_HWEIGHT 254 def_bool y 255 256config GENERIC_CSUM 257 def_bool y 258 259config GENERIC_CALIBRATE_DELAY 260 def_bool y 261 262config ZONE_DMA32 263 def_bool y 264 265config HAVE_GENERIC_GUP 266 def_bool y 267 268config ARCH_ENABLE_MEMORY_HOTPLUG 269 def_bool y 270 271config SMP 272 def_bool y 273 274config KERNEL_MODE_NEON 275 def_bool y 276 277config FIX_EARLYCON_MEM 278 def_bool y 279 280config PGTABLE_LEVELS 281 int 282 default 2 if ARM64_16K_PAGES && ARM64_VA_BITS_36 283 default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42 284 default 3 if ARM64_64K_PAGES && (ARM64_VA_BITS_48 || ARM64_USER_VA_BITS_52) 285 default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39 286 default 3 if ARM64_16K_PAGES && ARM64_VA_BITS_47 287 default 4 if !ARM64_64K_PAGES && ARM64_VA_BITS_48 288 289config ARCH_SUPPORTS_UPROBES 290 def_bool y 291 292config ARCH_PROC_KCORE_TEXT 293 def_bool y 294 295source "arch/arm64/Kconfig.platforms" 296 297menu "Kernel Features" 298 299menu "ARM errata workarounds via the alternatives framework" 300 301config ARM64_WORKAROUND_CLEAN_CACHE 302 bool 303 304config ARM64_ERRATUM_826319 305 bool "Cortex-A53: 826319: System might deadlock if a write cannot complete until read data is accepted" 306 default y 307 select ARM64_WORKAROUND_CLEAN_CACHE 308 help 309 This option adds an alternative code sequence to work around ARM 310 erratum 826319 on Cortex-A53 parts up to r0p2 with an AMBA 4 ACE or 311 AXI master interface and an L2 cache. 312 313 If a Cortex-A53 uses an AMBA AXI4 ACE interface to other processors 314 and is unable to accept a certain write via this interface, it will 315 not progress on read data presented on the read data channel and the 316 system can deadlock. 317 318 The workaround promotes data cache clean instructions to 319 data cache clean-and-invalidate. 320 Please note that this does not necessarily enable the workaround, 321 as it depends on the alternative framework, which will only patch 322 the kernel if an affected CPU is detected. 323 324 If unsure, say Y. 325 326config ARM64_ERRATUM_827319 327 bool "Cortex-A53: 827319: Data cache clean instructions might cause overlapping transactions to the interconnect" 328 default y 329 select ARM64_WORKAROUND_CLEAN_CACHE 330 help 331 This option adds an alternative code sequence to work around ARM 332 erratum 827319 on Cortex-A53 parts up to r0p2 with an AMBA 5 CHI 333 master interface and an L2 cache. 334 335 Under certain conditions this erratum can cause a clean line eviction 336 to occur at the same time as another transaction to the same address 337 on the AMBA 5 CHI interface, which can cause data corruption if the 338 interconnect reorders the two transactions. 339 340 The workaround promotes data cache clean instructions to 341 data cache clean-and-invalidate. 342 Please note that this does not necessarily enable the workaround, 343 as it depends on the alternative framework, which will only patch 344 the kernel if an affected CPU is detected. 345 346 If unsure, say Y. 347 348config ARM64_ERRATUM_824069 349 bool "Cortex-A53: 824069: Cache line might not be marked as clean after a CleanShared snoop" 350 default y 351 select ARM64_WORKAROUND_CLEAN_CACHE 352 help 353 This option adds an alternative code sequence to work around ARM 354 erratum 824069 on Cortex-A53 parts up to r0p2 when it is connected 355 to a coherent interconnect. 356 357 If a Cortex-A53 processor is executing a store or prefetch for 358 write instruction at the same time as a processor in another 359 cluster is executing a cache maintenance operation to the same 360 address, then this erratum might cause a clean cache line to be 361 incorrectly marked as dirty. 362 363 The workaround promotes data cache clean instructions to 364 data cache clean-and-invalidate. 365 Please note that this option does not necessarily enable the 366 workaround, as it depends on the alternative framework, which will 367 only patch the kernel if an affected CPU is detected. 368 369 If unsure, say Y. 370 371config ARM64_ERRATUM_819472 372 bool "Cortex-A53: 819472: Store exclusive instructions might cause data corruption" 373 default y 374 select ARM64_WORKAROUND_CLEAN_CACHE 375 help 376 This option adds an alternative code sequence to work around ARM 377 erratum 819472 on Cortex-A53 parts up to r0p1 with an L2 cache 378 present when it is connected to a coherent interconnect. 379 380 If the processor is executing a load and store exclusive sequence at 381 the same time as a processor in another cluster is executing a cache 382 maintenance operation to the same address, then this erratum might 383 cause data corruption. 384 385 The workaround promotes data cache clean instructions to 386 data cache clean-and-invalidate. 387 Please note that this does not necessarily enable the workaround, 388 as it depends on the alternative framework, which will only patch 389 the kernel if an affected CPU is detected. 390 391 If unsure, say Y. 392 393config ARM64_ERRATUM_832075 394 bool "Cortex-A57: 832075: possible deadlock on mixing exclusive memory accesses with device loads" 395 default y 396 help 397 This option adds an alternative code sequence to work around ARM 398 erratum 832075 on Cortex-A57 parts up to r1p2. 399 400 Affected Cortex-A57 parts might deadlock when exclusive load/store 401 instructions to Write-Back memory are mixed with Device loads. 402 403 The workaround is to promote device loads to use Load-Acquire 404 semantics. 405 Please note that this does not necessarily enable the workaround, 406 as it depends on the alternative framework, which will only patch 407 the kernel if an affected CPU is detected. 408 409 If unsure, say Y. 410 411config ARM64_ERRATUM_834220 412 bool "Cortex-A57: 834220: Stage 2 translation fault might be incorrectly reported in presence of a Stage 1 fault" 413 depends on KVM 414 default y 415 help 416 This option adds an alternative code sequence to work around ARM 417 erratum 834220 on Cortex-A57 parts up to r1p2. 418 419 Affected Cortex-A57 parts might report a Stage 2 translation 420 fault as the result of a Stage 1 fault for load crossing a 421 page boundary when there is a permission or device memory 422 alignment fault at Stage 1 and a translation fault at Stage 2. 423 424 The workaround is to verify that the Stage 1 translation 425 doesn't generate a fault before handling the Stage 2 fault. 426 Please note that this does not necessarily enable the workaround, 427 as it depends on the alternative framework, which will only patch 428 the kernel if an affected CPU is detected. 429 430 If unsure, say Y. 431 432config ARM64_ERRATUM_845719 433 bool "Cortex-A53: 845719: a load might read incorrect data" 434 depends on COMPAT 435 default y 436 help 437 This option adds an alternative code sequence to work around ARM 438 erratum 845719 on Cortex-A53 parts up to r0p4. 439 440 When running a compat (AArch32) userspace on an affected Cortex-A53 441 part, a load at EL0 from a virtual address that matches the bottom 32 442 bits of the virtual address used by a recent load at (AArch64) EL1 443 might return incorrect data. 444 445 The workaround is to write the contextidr_el1 register on exception 446 return to a 32-bit task. 447 Please note that this does not necessarily enable the workaround, 448 as it depends on the alternative framework, which will only patch 449 the kernel if an affected CPU is detected. 450 451 If unsure, say Y. 452 453config ARM64_ERRATUM_843419 454 bool "Cortex-A53: 843419: A load or store might access an incorrect address" 455 default y 456 select ARM64_MODULE_PLTS if MODULES 457 help 458 This option links the kernel with '--fix-cortex-a53-843419' and 459 enables PLT support to replace certain ADRP instructions, which can 460 cause subsequent memory accesses to use an incorrect address on 461 Cortex-A53 parts up to r0p4. 462 463 If unsure, say Y. 464 465config ARM64_ERRATUM_1024718 466 bool "Cortex-A55: 1024718: Update of DBM/AP bits without break before make might result in incorrect update" 467 default y 468 help 469 This option adds a workaround for ARM Cortex-A55 Erratum 1024718. 470 471 Affected Cortex-A55 cores (r0p0, r0p1, r1p0) could cause incorrect 472 update of the hardware dirty bit when the DBM/AP bits are updated 473 without a break-before-make. The workaround is to disable the usage 474 of hardware DBM locally on the affected cores. CPUs not affected by 475 this erratum will continue to use the feature. 476 477 If unsure, say Y. 478 479config ARM64_ERRATUM_1418040 480 bool "Cortex-A76/Neoverse-N1: MRC read following MRRC read of specific Generic Timer in AArch32 might give incorrect result" 481 default y 482 depends on COMPAT 483 help 484 This option adds a workaround for ARM Cortex-A76/Neoverse-N1 485 errata 1188873 and 1418040. 486 487 Affected Cortex-A76/Neoverse-N1 cores (r0p0 to r3p1) could 488 cause register corruption when accessing the timer registers 489 from AArch32 userspace. 490 491 If unsure, say Y. 492 493config ARM64_ERRATUM_1165522 494 bool "Cortex-A76: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation" 495 default y 496 help 497 This option adds a workaround for ARM Cortex-A76 erratum 1165522. 498 499 Affected Cortex-A76 cores (r0p0, r1p0, r2p0) could end-up with 500 corrupted TLBs by speculating an AT instruction during a guest 501 context switch. 502 503 If unsure, say Y. 504 505config ARM64_ERRATUM_1286807 506 bool "Cortex-A76: Modification of the translation table for a virtual address might lead to read-after-read ordering violation" 507 default y 508 select ARM64_WORKAROUND_REPEAT_TLBI 509 help 510 This option adds a workaround for ARM Cortex-A76 erratum 1286807. 511 512 On the affected Cortex-A76 cores (r0p0 to r3p0), if a virtual 513 address for a cacheable mapping of a location is being 514 accessed by a core while another core is remapping the virtual 515 address to a new physical page using the recommended 516 break-before-make sequence, then under very rare circumstances 517 TLBI+DSB completes before a read using the translation being 518 invalidated has been observed by other observers. The 519 workaround repeats the TLBI+DSB operation. 520 521 If unsure, say Y. 522 523config ARM64_ERRATUM_1463225 524 bool "Cortex-A76: Software Step might prevent interrupt recognition" 525 default y 526 help 527 This option adds a workaround for Arm Cortex-A76 erratum 1463225. 528 529 On the affected Cortex-A76 cores (r0p0 to r3p1), software stepping 530 of a system call instruction (SVC) can prevent recognition of 531 subsequent interrupts when software stepping is disabled in the 532 exception handler of the system call and either kernel debugging 533 is enabled or VHE is in use. 534 535 Work around the erratum by triggering a dummy step exception 536 when handling a system call from a task that is being stepped 537 in a VHE configuration of the kernel. 538 539 If unsure, say Y. 540 541config CAVIUM_ERRATUM_22375 542 bool "Cavium erratum 22375, 24313" 543 default y 544 help 545 Enable workaround for errata 22375 and 24313. 546 547 This implements two gicv3-its errata workarounds for ThunderX. Both 548 with a small impact affecting only ITS table allocation. 549 550 erratum 22375: only alloc 8MB table size 551 erratum 24313: ignore memory access type 552 553 The fixes are in ITS initialization and basically ignore memory access 554 type and table size provided by the TYPER and BASER registers. 555 556 If unsure, say Y. 557 558config CAVIUM_ERRATUM_23144 559 bool "Cavium erratum 23144: ITS SYNC hang on dual socket system" 560 depends on NUMA 561 default y 562 help 563 ITS SYNC command hang for cross node io and collections/cpu mapping. 564 565 If unsure, say Y. 566 567config CAVIUM_ERRATUM_23154 568 bool "Cavium erratum 23154: Access to ICC_IAR1_EL1 is not sync'ed" 569 default y 570 help 571 The gicv3 of ThunderX requires a modified version for 572 reading the IAR status to ensure data synchronization 573 (access to icc_iar1_el1 is not sync'ed before and after). 574 575 If unsure, say Y. 576 577config CAVIUM_ERRATUM_27456 578 bool "Cavium erratum 27456: Broadcast TLBI instructions may cause icache corruption" 579 default y 580 help 581 On ThunderX T88 pass 1.x through 2.1 parts, broadcast TLBI 582 instructions may cause the icache to become corrupted if it 583 contains data for a non-current ASID. The fix is to 584 invalidate the icache when changing the mm context. 585 586 If unsure, say Y. 587 588config CAVIUM_ERRATUM_30115 589 bool "Cavium erratum 30115: Guest may disable interrupts in host" 590 default y 591 help 592 On ThunderX T88 pass 1.x through 2.2, T81 pass 1.0 through 593 1.2, and T83 Pass 1.0, KVM guest execution may disable 594 interrupts in host. Trapping both GICv3 group-0 and group-1 595 accesses sidesteps the issue. 596 597 If unsure, say Y. 598 599config QCOM_FALKOR_ERRATUM_1003 600 bool "Falkor E1003: Incorrect translation due to ASID change" 601 default y 602 help 603 On Falkor v1, an incorrect ASID may be cached in the TLB when ASID 604 and BADDR are changed together in TTBRx_EL1. Since we keep the ASID 605 in TTBR1_EL1, this situation only occurs in the entry trampoline and 606 then only for entries in the walk cache, since the leaf translation 607 is unchanged. Work around the erratum by invalidating the walk cache 608 entries for the trampoline before entering the kernel proper. 609 610config ARM64_WORKAROUND_REPEAT_TLBI 611 bool 612 613config QCOM_FALKOR_ERRATUM_1009 614 bool "Falkor E1009: Prematurely complete a DSB after a TLBI" 615 default y 616 select ARM64_WORKAROUND_REPEAT_TLBI 617 help 618 On Falkor v1, the CPU may prematurely complete a DSB following a 619 TLBI xxIS invalidate maintenance operation. Repeat the TLBI operation 620 one more time to fix the issue. 621 622 If unsure, say Y. 623 624config QCOM_QDF2400_ERRATUM_0065 625 bool "QDF2400 E0065: Incorrect GITS_TYPER.ITT_Entry_size" 626 default y 627 help 628 On Qualcomm Datacenter Technologies QDF2400 SoC, ITS hardware reports 629 ITE size incorrectly. The GITS_TYPER.ITT_Entry_size field should have 630 been indicated as 16Bytes (0xf), not 8Bytes (0x7). 631 632 If unsure, say Y. 633 634config SOCIONEXT_SYNQUACER_PREITS 635 bool "Socionext Synquacer: Workaround for GICv3 pre-ITS" 636 default y 637 help 638 Socionext Synquacer SoCs implement a separate h/w block to generate 639 MSI doorbell writes with non-zero values for the device ID. 640 641 If unsure, say Y. 642 643config HISILICON_ERRATUM_161600802 644 bool "Hip07 161600802: Erroneous redistributor VLPI base" 645 default y 646 help 647 The HiSilicon Hip07 SoC uses the wrong redistributor base 648 when issued ITS commands such as VMOVP and VMAPP, and requires 649 a 128kB offset to be applied to the target address in this commands. 650 651 If unsure, say Y. 652 653config QCOM_FALKOR_ERRATUM_E1041 654 bool "Falkor E1041: Speculative instruction fetches might cause errant memory access" 655 default y 656 help 657 Falkor CPU may speculatively fetch instructions from an improper 658 memory location when MMU translation is changed from SCTLR_ELn[M]=1 659 to SCTLR_ELn[M]=0. Prefix an ISB instruction to fix the problem. 660 661 If unsure, say Y. 662 663config FUJITSU_ERRATUM_010001 664 bool "Fujitsu-A64FX erratum E#010001: Undefined fault may occur wrongly" 665 default y 666 help 667 This option adds a workaround for Fujitsu-A64FX erratum E#010001. 668 On some variants of the Fujitsu-A64FX cores ver(1.0, 1.1), memory 669 accesses may cause undefined fault (Data abort, DFSC=0b111111). 670 This fault occurs under a specific hardware condition when a 671 load/store instruction performs an address translation using: 672 case-1 TTBR0_EL1 with TCR_EL1.NFD0 == 1. 673 case-2 TTBR0_EL2 with TCR_EL2.NFD0 == 1. 674 case-3 TTBR1_EL1 with TCR_EL1.NFD1 == 1. 675 case-4 TTBR1_EL2 with TCR_EL2.NFD1 == 1. 676 677 The workaround is to ensure these bits are clear in TCR_ELx. 678 The workaround only affects the Fujitsu-A64FX. 679 680 If unsure, say Y. 681 682endmenu 683 684 685choice 686 prompt "Page size" 687 default ARM64_4K_PAGES 688 help 689 Page size (translation granule) configuration. 690 691config ARM64_4K_PAGES 692 bool "4KB" 693 help 694 This feature enables 4KB pages support. 695 696config ARM64_16K_PAGES 697 bool "16KB" 698 help 699 The system will use 16KB pages support. AArch32 emulation 700 requires applications compiled with 16K (or a multiple of 16K) 701 aligned segments. 702 703config ARM64_64K_PAGES 704 bool "64KB" 705 help 706 This feature enables 64KB pages support (4KB by default) 707 allowing only two levels of page tables and faster TLB 708 look-up. AArch32 emulation requires applications compiled 709 with 64K aligned segments. 710 711endchoice 712 713choice 714 prompt "Virtual address space size" 715 default ARM64_VA_BITS_39 if ARM64_4K_PAGES 716 default ARM64_VA_BITS_47 if ARM64_16K_PAGES 717 default ARM64_VA_BITS_42 if ARM64_64K_PAGES 718 help 719 Allows choosing one of multiple possible virtual address 720 space sizes. The level of translation table is determined by 721 a combination of page size and virtual address space size. 722 723config ARM64_VA_BITS_36 724 bool "36-bit" if EXPERT 725 depends on ARM64_16K_PAGES 726 727config ARM64_VA_BITS_39 728 bool "39-bit" 729 depends on ARM64_4K_PAGES 730 731config ARM64_VA_BITS_42 732 bool "42-bit" 733 depends on ARM64_64K_PAGES 734 735config ARM64_VA_BITS_47 736 bool "47-bit" 737 depends on ARM64_16K_PAGES 738 739config ARM64_VA_BITS_48 740 bool "48-bit" 741 742config ARM64_USER_VA_BITS_52 743 bool "52-bit (user)" 744 depends on ARM64_64K_PAGES && (ARM64_PAN || !ARM64_SW_TTBR0_PAN) 745 help 746 Enable 52-bit virtual addressing for userspace when explicitly 747 requested via a hint to mmap(). The kernel will continue to 748 use 48-bit virtual addresses for its own mappings. 749 750 NOTE: Enabling 52-bit virtual addressing in conjunction with 751 ARMv8.3 Pointer Authentication will result in the PAC being 752 reduced from 7 bits to 3 bits, which may have a significant 753 impact on its susceptibility to brute-force attacks. 754 755 If unsure, select 48-bit virtual addressing instead. 756 757endchoice 758 759config ARM64_FORCE_52BIT 760 bool "Force 52-bit virtual addresses for userspace" 761 depends on ARM64_USER_VA_BITS_52 && EXPERT 762 help 763 For systems with 52-bit userspace VAs enabled, the kernel will attempt 764 to maintain compatibility with older software by providing 48-bit VAs 765 unless a hint is supplied to mmap. 766 767 This configuration option disables the 48-bit compatibility logic, and 768 forces all userspace addresses to be 52-bit on HW that supports it. One 769 should only enable this configuration option for stress testing userspace 770 memory management code. If unsure say N here. 771 772config ARM64_VA_BITS 773 int 774 default 36 if ARM64_VA_BITS_36 775 default 39 if ARM64_VA_BITS_39 776 default 42 if ARM64_VA_BITS_42 777 default 47 if ARM64_VA_BITS_47 778 default 48 if ARM64_VA_BITS_48 || ARM64_USER_VA_BITS_52 779 780choice 781 prompt "Physical address space size" 782 default ARM64_PA_BITS_48 783 help 784 Choose the maximum physical address range that the kernel will 785 support. 786 787config ARM64_PA_BITS_48 788 bool "48-bit" 789 790config ARM64_PA_BITS_52 791 bool "52-bit (ARMv8.2)" 792 depends on ARM64_64K_PAGES 793 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN 794 help 795 Enable support for a 52-bit physical address space, introduced as 796 part of the ARMv8.2-LPA extension. 797 798 With this enabled, the kernel will also continue to work on CPUs that 799 do not support ARMv8.2-LPA, but with some added memory overhead (and 800 minor performance overhead). 801 802endchoice 803 804config ARM64_PA_BITS 805 int 806 default 48 if ARM64_PA_BITS_48 807 default 52 if ARM64_PA_BITS_52 808 809config CPU_BIG_ENDIAN 810 bool "Build big-endian kernel" 811 help 812 Say Y if you plan on running a kernel in big-endian mode. 813 814config SCHED_MC 815 bool "Multi-core scheduler support" 816 help 817 Multi-core scheduler support improves the CPU scheduler's decision 818 making when dealing with multi-core CPU chips at a cost of slightly 819 increased overhead in some places. If unsure say N here. 820 821config SCHED_SMT 822 bool "SMT scheduler support" 823 help 824 Improves the CPU scheduler's decision making when dealing with 825 MultiThreading at a cost of slightly increased overhead in some 826 places. If unsure say N here. 827 828config NR_CPUS 829 int "Maximum number of CPUs (2-4096)" 830 range 2 4096 831 default "256" 832 833config HOTPLUG_CPU 834 bool "Support for hot-pluggable CPUs" 835 select GENERIC_IRQ_MIGRATION 836 help 837 Say Y here to experiment with turning CPUs off and on. CPUs 838 can be controlled through /sys/devices/system/cpu. 839 840# Common NUMA Features 841config NUMA 842 bool "Numa Memory Allocation and Scheduler Support" 843 select ACPI_NUMA if ACPI 844 select OF_NUMA 845 help 846 Enable NUMA (Non Uniform Memory Access) support. 847 848 The kernel will try to allocate memory used by a CPU on the 849 local memory of the CPU and add some more 850 NUMA awareness to the kernel. 851 852config NODES_SHIFT 853 int "Maximum NUMA Nodes (as a power of 2)" 854 range 1 10 855 default "2" 856 depends on NEED_MULTIPLE_NODES 857 help 858 Specify the maximum number of NUMA Nodes available on the target 859 system. Increases memory reserved to accommodate various tables. 860 861config USE_PERCPU_NUMA_NODE_ID 862 def_bool y 863 depends on NUMA 864 865config HAVE_SETUP_PER_CPU_AREA 866 def_bool y 867 depends on NUMA 868 869config NEED_PER_CPU_EMBED_FIRST_CHUNK 870 def_bool y 871 depends on NUMA 872 873config HOLES_IN_ZONE 874 def_bool y 875 876source "kernel/Kconfig.hz" 877 878config ARCH_SUPPORTS_DEBUG_PAGEALLOC 879 def_bool y 880 881config ARCH_SPARSEMEM_ENABLE 882 def_bool y 883 select SPARSEMEM_VMEMMAP_ENABLE 884 885config ARCH_SPARSEMEM_DEFAULT 886 def_bool ARCH_SPARSEMEM_ENABLE 887 888config ARCH_SELECT_MEMORY_MODEL 889 def_bool ARCH_SPARSEMEM_ENABLE 890 891config ARCH_FLATMEM_ENABLE 892 def_bool !NUMA 893 894config HAVE_ARCH_PFN_VALID 895 def_bool y 896 897config HW_PERF_EVENTS 898 def_bool y 899 depends on ARM_PMU 900 901config SYS_SUPPORTS_HUGETLBFS 902 def_bool y 903 904config ARCH_WANT_HUGE_PMD_SHARE 905 def_bool y if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36) 906 907config ARCH_HAS_CACHE_LINE_SIZE 908 def_bool y 909 910config ARCH_ENABLE_SPLIT_PMD_PTLOCK 911 def_bool y if PGTABLE_LEVELS > 2 912 913config SECCOMP 914 bool "Enable seccomp to safely compute untrusted bytecode" 915 ---help--- 916 This kernel feature is useful for number crunching applications 917 that may need to compute untrusted bytecode during their 918 execution. By using pipes or other transports made available to 919 the process as file descriptors supporting the read/write 920 syscalls, it's possible to isolate those applications in 921 their own address space using seccomp. Once seccomp is 922 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 923 and the task is only allowed to execute a few safe syscalls 924 defined by each seccomp mode. 925 926config PARAVIRT 927 bool "Enable paravirtualization code" 928 help 929 This changes the kernel so it can modify itself when it is run 930 under a hypervisor, potentially improving performance significantly 931 over full virtualization. 932 933config PARAVIRT_TIME_ACCOUNTING 934 bool "Paravirtual steal time accounting" 935 select PARAVIRT 936 default n 937 help 938 Select this option to enable fine granularity task steal time 939 accounting. Time spent executing other tasks in parallel with 940 the current vCPU is discounted from the vCPU power. To account for 941 that, there can be a small performance impact. 942 943 If in doubt, say N here. 944 945config KEXEC 946 depends on PM_SLEEP_SMP 947 select KEXEC_CORE 948 bool "kexec system call" 949 ---help--- 950 kexec is a system call that implements the ability to shutdown your 951 current kernel, and to start another kernel. It is like a reboot 952 but it is independent of the system firmware. And like a reboot 953 you can start any kernel with it, not just Linux. 954 955config KEXEC_FILE 956 bool "kexec file based system call" 957 select KEXEC_CORE 958 help 959 This is new version of kexec system call. This system call is 960 file based and takes file descriptors as system call argument 961 for kernel and initramfs as opposed to list of segments as 962 accepted by previous system call. 963 964config KEXEC_VERIFY_SIG 965 bool "Verify kernel signature during kexec_file_load() syscall" 966 depends on KEXEC_FILE 967 help 968 Select this option to verify a signature with loaded kernel 969 image. If configured, any attempt of loading a image without 970 valid signature will fail. 971 972 In addition to that option, you need to enable signature 973 verification for the corresponding kernel image type being 974 loaded in order for this to work. 975 976config KEXEC_IMAGE_VERIFY_SIG 977 bool "Enable Image signature verification support" 978 default y 979 depends on KEXEC_VERIFY_SIG 980 depends on EFI && SIGNED_PE_FILE_VERIFICATION 981 help 982 Enable Image signature verification support. 983 984comment "Support for PE file signature verification disabled" 985 depends on KEXEC_VERIFY_SIG 986 depends on !EFI || !SIGNED_PE_FILE_VERIFICATION 987 988config CRASH_DUMP 989 bool "Build kdump crash kernel" 990 help 991 Generate crash dump after being started by kexec. This should 992 be normally only set in special crash dump kernels which are 993 loaded in the main kernel with kexec-tools into a specially 994 reserved region and then later executed after a crash by 995 kdump/kexec. 996 997 For more details see Documentation/kdump/kdump.txt 998 999config XEN_DOM0 1000 def_bool y 1001 depends on XEN 1002 1003config XEN 1004 bool "Xen guest support on ARM64" 1005 depends on ARM64 && OF 1006 select SWIOTLB_XEN 1007 select PARAVIRT 1008 help 1009 Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64. 1010 1011config FORCE_MAX_ZONEORDER 1012 int 1013 default "14" if (ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE) 1014 default "12" if (ARM64_16K_PAGES && TRANSPARENT_HUGEPAGE) 1015 default "11" 1016 help 1017 The kernel memory allocator divides physically contiguous memory 1018 blocks into "zones", where each zone is a power of two number of 1019 pages. This option selects the largest power of two that the kernel 1020 keeps in the memory allocator. If you need to allocate very large 1021 blocks of physically contiguous memory, then you may need to 1022 increase this value. 1023 1024 This config option is actually maximum order plus one. For example, 1025 a value of 11 means that the largest free memory block is 2^10 pages. 1026 1027 We make sure that we can allocate upto a HugePage size for each configuration. 1028 Hence we have : 1029 MAX_ORDER = (PMD_SHIFT - PAGE_SHIFT) + 1 => PAGE_SHIFT - 2 1030 1031 However for 4K, we choose a higher default value, 11 as opposed to 10, giving us 1032 4M allocations matching the default size used by generic code. 1033 1034config UNMAP_KERNEL_AT_EL0 1035 bool "Unmap kernel when running in userspace (aka \"KAISER\")" if EXPERT 1036 default y 1037 help 1038 Speculation attacks against some high-performance processors can 1039 be used to bypass MMU permission checks and leak kernel data to 1040 userspace. This can be defended against by unmapping the kernel 1041 when running in userspace, mapping it back in on exception entry 1042 via a trampoline page in the vector table. 1043 1044 If unsure, say Y. 1045 1046config HARDEN_BRANCH_PREDICTOR 1047 bool "Harden the branch predictor against aliasing attacks" if EXPERT 1048 default y 1049 help 1050 Speculation attacks against some high-performance processors rely on 1051 being able to manipulate the branch predictor for a victim context by 1052 executing aliasing branches in the attacker context. Such attacks 1053 can be partially mitigated against by clearing internal branch 1054 predictor state and limiting the prediction logic in some situations. 1055 1056 This config option will take CPU-specific actions to harden the 1057 branch predictor against aliasing attacks and may rely on specific 1058 instruction sequences or control bits being set by the system 1059 firmware. 1060 1061 If unsure, say Y. 1062 1063config HARDEN_EL2_VECTORS 1064 bool "Harden EL2 vector mapping against system register leak" if EXPERT 1065 default y 1066 help 1067 Speculation attacks against some high-performance processors can 1068 be used to leak privileged information such as the vector base 1069 register, resulting in a potential defeat of the EL2 layout 1070 randomization. 1071 1072 This config option will map the vectors to a fixed location, 1073 independent of the EL2 code mapping, so that revealing VBAR_EL2 1074 to an attacker does not give away any extra information. This 1075 only gets enabled on affected CPUs. 1076 1077 If unsure, say Y. 1078 1079config ARM64_SSBD 1080 bool "Speculative Store Bypass Disable" if EXPERT 1081 default y 1082 help 1083 This enables mitigation of the bypassing of previous stores 1084 by speculative loads. 1085 1086 If unsure, say Y. 1087 1088config RODATA_FULL_DEFAULT_ENABLED 1089 bool "Apply r/o permissions of VM areas also to their linear aliases" 1090 default y 1091 help 1092 Apply read-only attributes of VM areas to the linear alias of 1093 the backing pages as well. This prevents code or read-only data 1094 from being modified (inadvertently or intentionally) via another 1095 mapping of the same memory page. This additional enhancement can 1096 be turned off at runtime by passing rodata=[off|on] (and turned on 1097 with rodata=full if this option is set to 'n') 1098 1099 This requires the linear region to be mapped down to pages, 1100 which may adversely affect performance in some cases. 1101 1102config ARM64_SW_TTBR0_PAN 1103 bool "Emulate Privileged Access Never using TTBR0_EL1 switching" 1104 help 1105 Enabling this option prevents the kernel from accessing 1106 user-space memory directly by pointing TTBR0_EL1 to a reserved 1107 zeroed area and reserved ASID. The user access routines 1108 restore the valid TTBR0_EL1 temporarily. 1109 1110menuconfig COMPAT 1111 bool "Kernel support for 32-bit EL0" 1112 depends on ARM64_4K_PAGES || EXPERT 1113 select COMPAT_BINFMT_ELF if BINFMT_ELF 1114 select HAVE_UID16 1115 select OLD_SIGSUSPEND3 1116 select COMPAT_OLD_SIGACTION 1117 help 1118 This option enables support for a 32-bit EL0 running under a 64-bit 1119 kernel at EL1. AArch32-specific components such as system calls, 1120 the user helper functions, VFP support and the ptrace interface are 1121 handled appropriately by the kernel. 1122 1123 If you use a page size other than 4KB (i.e, 16KB or 64KB), please be aware 1124 that you will only be able to execute AArch32 binaries that were compiled 1125 with page size aligned segments. 1126 1127 If you want to execute 32-bit userspace applications, say Y. 1128 1129if COMPAT 1130 1131config KUSER_HELPERS 1132 bool "Enable kuser helpers page for 32 bit applications" 1133 default y 1134 help 1135 Warning: disabling this option may break 32-bit user programs. 1136 1137 Provide kuser helpers to compat tasks. The kernel provides 1138 helper code to userspace in read only form at a fixed location 1139 to allow userspace to be independent of the CPU type fitted to 1140 the system. This permits binaries to be run on ARMv4 through 1141 to ARMv8 without modification. 1142 1143 See Documentation/arm/kernel_user_helpers.txt for details. 1144 1145 However, the fixed address nature of these helpers can be used 1146 by ROP (return orientated programming) authors when creating 1147 exploits. 1148 1149 If all of the binaries and libraries which run on your platform 1150 are built specifically for your platform, and make no use of 1151 these helpers, then you can turn this option off to hinder 1152 such exploits. However, in that case, if a binary or library 1153 relying on those helpers is run, it will not function correctly. 1154 1155 Say N here only if you are absolutely certain that you do not 1156 need these helpers; otherwise, the safe option is to say Y. 1157 1158 1159menuconfig ARMV8_DEPRECATED 1160 bool "Emulate deprecated/obsolete ARMv8 instructions" 1161 depends on SYSCTL 1162 help 1163 Legacy software support may require certain instructions 1164 that have been deprecated or obsoleted in the architecture. 1165 1166 Enable this config to enable selective emulation of these 1167 features. 1168 1169 If unsure, say Y 1170 1171if ARMV8_DEPRECATED 1172 1173config SWP_EMULATION 1174 bool "Emulate SWP/SWPB instructions" 1175 help 1176 ARMv8 obsoletes the use of A32 SWP/SWPB instructions such that 1177 they are always undefined. Say Y here to enable software 1178 emulation of these instructions for userspace using LDXR/STXR. 1179 1180 In some older versions of glibc [<=2.8] SWP is used during futex 1181 trylock() operations with the assumption that the code will not 1182 be preempted. This invalid assumption may be more likely to fail 1183 with SWP emulation enabled, leading to deadlock of the user 1184 application. 1185 1186 NOTE: when accessing uncached shared regions, LDXR/STXR rely 1187 on an external transaction monitoring block called a global 1188 monitor to maintain update atomicity. If your system does not 1189 implement a global monitor, this option can cause programs that 1190 perform SWP operations to uncached memory to deadlock. 1191 1192 If unsure, say Y 1193 1194config CP15_BARRIER_EMULATION 1195 bool "Emulate CP15 Barrier instructions" 1196 help 1197 The CP15 barrier instructions - CP15ISB, CP15DSB, and 1198 CP15DMB - are deprecated in ARMv8 (and ARMv7). It is 1199 strongly recommended to use the ISB, DSB, and DMB 1200 instructions instead. 1201 1202 Say Y here to enable software emulation of these 1203 instructions for AArch32 userspace code. When this option is 1204 enabled, CP15 barrier usage is traced which can help 1205 identify software that needs updating. 1206 1207 If unsure, say Y 1208 1209config SETEND_EMULATION 1210 bool "Emulate SETEND instruction" 1211 help 1212 The SETEND instruction alters the data-endianness of the 1213 AArch32 EL0, and is deprecated in ARMv8. 1214 1215 Say Y here to enable software emulation of the instruction 1216 for AArch32 userspace code. 1217 1218 Note: All the cpus on the system must have mixed endian support at EL0 1219 for this feature to be enabled. If a new CPU - which doesn't support mixed 1220 endian - is hotplugged in after this feature has been enabled, there could 1221 be unexpected results in the applications. 1222 1223 If unsure, say Y 1224endif 1225 1226endif 1227 1228menu "ARMv8.1 architectural features" 1229 1230config ARM64_HW_AFDBM 1231 bool "Support for hardware updates of the Access and Dirty page flags" 1232 default y 1233 help 1234 The ARMv8.1 architecture extensions introduce support for 1235 hardware updates of the access and dirty information in page 1236 table entries. When enabled in TCR_EL1 (HA and HD bits) on 1237 capable processors, accesses to pages with PTE_AF cleared will 1238 set this bit instead of raising an access flag fault. 1239 Similarly, writes to read-only pages with the DBM bit set will 1240 clear the read-only bit (AP[2]) instead of raising a 1241 permission fault. 1242 1243 Kernels built with this configuration option enabled continue 1244 to work on pre-ARMv8.1 hardware and the performance impact is 1245 minimal. If unsure, say Y. 1246 1247config ARM64_PAN 1248 bool "Enable support for Privileged Access Never (PAN)" 1249 default y 1250 help 1251 Privileged Access Never (PAN; part of the ARMv8.1 Extensions) 1252 prevents the kernel or hypervisor from accessing user-space (EL0) 1253 memory directly. 1254 1255 Choosing this option will cause any unprotected (not using 1256 copy_to_user et al) memory access to fail with a permission fault. 1257 1258 The feature is detected at runtime, and will remain as a 'nop' 1259 instruction if the cpu does not implement the feature. 1260 1261config ARM64_LSE_ATOMICS 1262 bool "Atomic instructions" 1263 default y 1264 help 1265 As part of the Large System Extensions, ARMv8.1 introduces new 1266 atomic instructions that are designed specifically to scale in 1267 very large systems. 1268 1269 Say Y here to make use of these instructions for the in-kernel 1270 atomic routines. This incurs a small overhead on CPUs that do 1271 not support these instructions and requires the kernel to be 1272 built with binutils >= 2.25 in order for the new instructions 1273 to be used. 1274 1275config ARM64_VHE 1276 bool "Enable support for Virtualization Host Extensions (VHE)" 1277 default y 1278 help 1279 Virtualization Host Extensions (VHE) allow the kernel to run 1280 directly at EL2 (instead of EL1) on processors that support 1281 it. This leads to better performance for KVM, as they reduce 1282 the cost of the world switch. 1283 1284 Selecting this option allows the VHE feature to be detected 1285 at runtime, and does not affect processors that do not 1286 implement this feature. 1287 1288endmenu 1289 1290menu "ARMv8.2 architectural features" 1291 1292config ARM64_UAO 1293 bool "Enable support for User Access Override (UAO)" 1294 default y 1295 help 1296 User Access Override (UAO; part of the ARMv8.2 Extensions) 1297 causes the 'unprivileged' variant of the load/store instructions to 1298 be overridden to be privileged. 1299 1300 This option changes get_user() and friends to use the 'unprivileged' 1301 variant of the load/store instructions. This ensures that user-space 1302 really did have access to the supplied memory. When addr_limit is 1303 set to kernel memory the UAO bit will be set, allowing privileged 1304 access to kernel memory. 1305 1306 Choosing this option will cause copy_to_user() et al to use user-space 1307 memory permissions. 1308 1309 The feature is detected at runtime, the kernel will use the 1310 regular load/store instructions if the cpu does not implement the 1311 feature. 1312 1313config ARM64_PMEM 1314 bool "Enable support for persistent memory" 1315 select ARCH_HAS_PMEM_API 1316 select ARCH_HAS_UACCESS_FLUSHCACHE 1317 help 1318 Say Y to enable support for the persistent memory API based on the 1319 ARMv8.2 DCPoP feature. 1320 1321 The feature is detected at runtime, and the kernel will use DC CVAC 1322 operations if DC CVAP is not supported (following the behaviour of 1323 DC CVAP itself if the system does not define a point of persistence). 1324 1325config ARM64_RAS_EXTN 1326 bool "Enable support for RAS CPU Extensions" 1327 default y 1328 help 1329 CPUs that support the Reliability, Availability and Serviceability 1330 (RAS) Extensions, part of ARMv8.2 are able to track faults and 1331 errors, classify them and report them to software. 1332 1333 On CPUs with these extensions system software can use additional 1334 barriers to determine if faults are pending and read the 1335 classification from a new set of registers. 1336 1337 Selecting this feature will allow the kernel to use these barriers 1338 and access the new registers if the system supports the extension. 1339 Platform RAS features may additionally depend on firmware support. 1340 1341config ARM64_CNP 1342 bool "Enable support for Common Not Private (CNP) translations" 1343 default y 1344 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN 1345 help 1346 Common Not Private (CNP) allows translation table entries to 1347 be shared between different PEs in the same inner shareable 1348 domain, so the hardware can use this fact to optimise the 1349 caching of such entries in the TLB. 1350 1351 Selecting this option allows the CNP feature to be detected 1352 at runtime, and does not affect PEs that do not implement 1353 this feature. 1354 1355endmenu 1356 1357menu "ARMv8.3 architectural features" 1358 1359config ARM64_PTR_AUTH 1360 bool "Enable support for pointer authentication" 1361 default y 1362 depends on !KVM || ARM64_VHE 1363 help 1364 Pointer authentication (part of the ARMv8.3 Extensions) provides 1365 instructions for signing and authenticating pointers against secret 1366 keys, which can be used to mitigate Return Oriented Programming (ROP) 1367 and other attacks. 1368 1369 This option enables these instructions at EL0 (i.e. for userspace). 1370 1371 Choosing this option will cause the kernel to initialise secret keys 1372 for each process at exec() time, with these keys being 1373 context-switched along with the process. 1374 1375 The feature is detected at runtime. If the feature is not present in 1376 hardware it will not be advertised to userspace/KVM guest nor will it 1377 be enabled. However, KVM guest also require VHE mode and hence 1378 CONFIG_ARM64_VHE=y option to use this feature. 1379 1380endmenu 1381 1382config ARM64_SVE 1383 bool "ARM Scalable Vector Extension support" 1384 default y 1385 depends on !KVM || ARM64_VHE 1386 help 1387 The Scalable Vector Extension (SVE) is an extension to the AArch64 1388 execution state which complements and extends the SIMD functionality 1389 of the base architecture to support much larger vectors and to enable 1390 additional vectorisation opportunities. 1391 1392 To enable use of this extension on CPUs that implement it, say Y. 1393 1394 On CPUs that support the SVE2 extensions, this option will enable 1395 those too. 1396 1397 Note that for architectural reasons, firmware _must_ implement SVE 1398 support when running on SVE capable hardware. The required support 1399 is present in: 1400 1401 * version 1.5 and later of the ARM Trusted Firmware 1402 * the AArch64 boot wrapper since commit 5e1261e08abf 1403 ("bootwrapper: SVE: Enable SVE for EL2 and below"). 1404 1405 For other firmware implementations, consult the firmware documentation 1406 or vendor. 1407 1408 If you need the kernel to boot on SVE-capable hardware with broken 1409 firmware, you may need to say N here until you get your firmware 1410 fixed. Otherwise, you may experience firmware panics or lockups when 1411 booting the kernel. If unsure and you are not observing these 1412 symptoms, you should assume that it is safe to say Y. 1413 1414 CPUs that support SVE are architecturally required to support the 1415 Virtualization Host Extensions (VHE), so the kernel makes no 1416 provision for supporting SVE alongside KVM without VHE enabled. 1417 Thus, you will need to enable CONFIG_ARM64_VHE if you want to support 1418 KVM in the same kernel image. 1419 1420config ARM64_MODULE_PLTS 1421 bool 1422 select HAVE_MOD_ARCH_SPECIFIC 1423 1424config ARM64_PSEUDO_NMI 1425 bool "Support for NMI-like interrupts" 1426 depends on BROKEN # 1556553607-46531-1-git-send-email-julien.thierry@arm.com 1427 select CONFIG_ARM_GIC_V3 1428 help 1429 Adds support for mimicking Non-Maskable Interrupts through the use of 1430 GIC interrupt priority. This support requires version 3 or later of 1431 ARM GIC. 1432 1433 This high priority configuration for interrupts needs to be 1434 explicitly enabled by setting the kernel parameter 1435 "irqchip.gicv3_pseudo_nmi" to 1. 1436 1437 If unsure, say N 1438 1439config RELOCATABLE 1440 bool 1441 help 1442 This builds the kernel as a Position Independent Executable (PIE), 1443 which retains all relocation metadata required to relocate the 1444 kernel binary at runtime to a different virtual address than the 1445 address it was linked at. 1446 Since AArch64 uses the RELA relocation format, this requires a 1447 relocation pass at runtime even if the kernel is loaded at the 1448 same address it was linked at. 1449 1450config RANDOMIZE_BASE 1451 bool "Randomize the address of the kernel image" 1452 select ARM64_MODULE_PLTS if MODULES 1453 select RELOCATABLE 1454 help 1455 Randomizes the virtual address at which the kernel image is 1456 loaded, as a security feature that deters exploit attempts 1457 relying on knowledge of the location of kernel internals. 1458 1459 It is the bootloader's job to provide entropy, by passing a 1460 random u64 value in /chosen/kaslr-seed at kernel entry. 1461 1462 When booting via the UEFI stub, it will invoke the firmware's 1463 EFI_RNG_PROTOCOL implementation (if available) to supply entropy 1464 to the kernel proper. In addition, it will randomise the physical 1465 location of the kernel Image as well. 1466 1467 If unsure, say N. 1468 1469config RANDOMIZE_MODULE_REGION_FULL 1470 bool "Randomize the module region over a 4 GB range" 1471 depends on RANDOMIZE_BASE 1472 default y 1473 help 1474 Randomizes the location of the module region inside a 4 GB window 1475 covering the core kernel. This way, it is less likely for modules 1476 to leak information about the location of core kernel data structures 1477 but it does imply that function calls between modules and the core 1478 kernel will need to be resolved via veneers in the module PLT. 1479 1480 When this option is not set, the module region will be randomized over 1481 a limited range that contains the [_stext, _etext] interval of the 1482 core kernel, so branch relocations are always in range. 1483 1484config CC_HAVE_STACKPROTECTOR_SYSREG 1485 def_bool $(cc-option,-mstack-protector-guard=sysreg -mstack-protector-guard-reg=sp_el0 -mstack-protector-guard-offset=0) 1486 1487config STACKPROTECTOR_PER_TASK 1488 def_bool y 1489 depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_SYSREG 1490 1491endmenu 1492 1493menu "Boot options" 1494 1495config ARM64_ACPI_PARKING_PROTOCOL 1496 bool "Enable support for the ARM64 ACPI parking protocol" 1497 depends on ACPI 1498 help 1499 Enable support for the ARM64 ACPI parking protocol. If disabled 1500 the kernel will not allow booting through the ARM64 ACPI parking 1501 protocol even if the corresponding data is present in the ACPI 1502 MADT table. 1503 1504config CMDLINE 1505 string "Default kernel command string" 1506 default "" 1507 help 1508 Provide a set of default command-line options at build time by 1509 entering them here. As a minimum, you should specify the the 1510 root device (e.g. root=/dev/nfs). 1511 1512config CMDLINE_FORCE 1513 bool "Always use the default kernel command string" 1514 help 1515 Always use the default kernel command string, even if the boot 1516 loader passes other arguments to the kernel. 1517 This is useful if you cannot or don't want to change the 1518 command-line options your boot loader passes to the kernel. 1519 1520config EFI_STUB 1521 bool 1522 1523config EFI 1524 bool "UEFI runtime support" 1525 depends on OF && !CPU_BIG_ENDIAN 1526 depends on KERNEL_MODE_NEON 1527 select ARCH_SUPPORTS_ACPI 1528 select LIBFDT 1529 select UCS2_STRING 1530 select EFI_PARAMS_FROM_FDT 1531 select EFI_RUNTIME_WRAPPERS 1532 select EFI_STUB 1533 select EFI_ARMSTUB 1534 default y 1535 help 1536 This option provides support for runtime services provided 1537 by UEFI firmware (such as non-volatile variables, realtime 1538 clock, and platform reset). A UEFI stub is also provided to 1539 allow the kernel to be booted as an EFI application. This 1540 is only useful on systems that have UEFI firmware. 1541 1542config DMI 1543 bool "Enable support for SMBIOS (DMI) tables" 1544 depends on EFI 1545 default y 1546 help 1547 This enables SMBIOS/DMI feature for systems. 1548 1549 This option is only useful on systems that have UEFI firmware. 1550 However, even with this option, the resultant kernel should 1551 continue to boot on existing non-UEFI platforms. 1552 1553endmenu 1554 1555config SYSVIPC_COMPAT 1556 def_bool y 1557 depends on COMPAT && SYSVIPC 1558 1559config ARCH_ENABLE_HUGEPAGE_MIGRATION 1560 def_bool y 1561 depends on HUGETLB_PAGE && MIGRATION 1562 1563menu "Power management options" 1564 1565source "kernel/power/Kconfig" 1566 1567config ARCH_HIBERNATION_POSSIBLE 1568 def_bool y 1569 depends on CPU_PM 1570 1571config ARCH_HIBERNATION_HEADER 1572 def_bool y 1573 depends on HIBERNATION 1574 1575config ARCH_SUSPEND_POSSIBLE 1576 def_bool y 1577 1578endmenu 1579 1580menu "CPU Power Management" 1581 1582source "drivers/cpuidle/Kconfig" 1583 1584source "drivers/cpufreq/Kconfig" 1585 1586endmenu 1587 1588source "drivers/firmware/Kconfig" 1589 1590source "drivers/acpi/Kconfig" 1591 1592source "arch/arm64/kvm/Kconfig" 1593 1594if CRYPTO 1595source "arch/arm64/crypto/Kconfig" 1596endif 1597