1# SPDX-License-Identifier: GPL-2.0-only 2config ARM64 3 def_bool y 4 select ACPI_APMT if ACPI 5 select ACPI_CCA_REQUIRED if ACPI 6 select ACPI_GENERIC_GSI if ACPI 7 select ACPI_GTDT if ACPI 8 select ACPI_HOTPLUG_CPU if ACPI_PROCESSOR && HOTPLUG_CPU 9 select ACPI_IORT if ACPI 10 select ACPI_REDUCED_HARDWARE_ONLY if ACPI 11 select ACPI_MCFG if (ACPI && PCI) 12 select ACPI_SPCR_TABLE if ACPI 13 select ACPI_PPTT if ACPI 14 select ARCH_HAS_DEBUG_WX 15 select ARCH_BINFMT_ELF_EXTRA_PHDRS 16 select ARCH_BINFMT_ELF_STATE 17 select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION 18 select ARCH_ENABLE_MEMORY_HOTPLUG 19 select ARCH_ENABLE_MEMORY_HOTREMOVE 20 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2 21 select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE 22 select ARCH_HAS_CACHE_LINE_SIZE 23 select ARCH_HAS_CC_PLATFORM 24 select ARCH_HAS_CRC32 25 select ARCH_HAS_CURRENT_STACK_POINTER 26 select ARCH_HAS_DEBUG_VIRTUAL 27 select ARCH_HAS_DEBUG_VM_PGTABLE 28 select ARCH_HAS_DMA_OPS if XEN 29 select ARCH_HAS_DMA_PREP_COHERENT 30 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 31 select ARCH_HAS_FAST_MULTIPLIER 32 select ARCH_HAS_FORTIFY_SOURCE 33 select ARCH_HAS_GCOV_PROFILE_ALL 34 select ARCH_HAS_GIGANTIC_PAGE 35 select ARCH_HAS_KCOV 36 select ARCH_HAS_KERNEL_FPU_SUPPORT if KERNEL_MODE_NEON 37 select ARCH_HAS_KEEPINITRD 38 select ARCH_HAS_MEMBARRIER_SYNC_CORE 39 select ARCH_HAS_MEM_ENCRYPT 40 select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS 41 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 42 select ARCH_HAS_NONLEAF_PMD_YOUNG if ARM64_HAFT 43 select ARCH_HAS_PTE_DEVMAP 44 select ARCH_HAS_PTE_SPECIAL 45 select ARCH_HAS_HW_PTE_YOUNG 46 select ARCH_HAS_SETUP_DMA_OPS 47 select ARCH_HAS_SET_DIRECT_MAP 48 select ARCH_HAS_SET_MEMORY 49 select ARCH_HAS_MEM_ENCRYPT 50 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 51 select ARCH_STACKWALK 52 select ARCH_HAS_STRICT_KERNEL_RWX 53 select ARCH_HAS_STRICT_MODULE_RWX 54 select ARCH_HAS_SYNC_DMA_FOR_DEVICE 55 select ARCH_HAS_SYNC_DMA_FOR_CPU 56 select ARCH_HAS_SYSCALL_WRAPPER 57 select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST 58 select ARCH_HAS_ZONE_DMA_SET if EXPERT 59 select ARCH_HAVE_ELF_PROT 60 select ARCH_HAVE_NMI_SAFE_CMPXCHG 61 select ARCH_HAVE_TRACE_MMIO_ACCESS 62 select ARCH_INLINE_READ_LOCK if !PREEMPTION 63 select ARCH_INLINE_READ_LOCK_BH if !PREEMPTION 64 select ARCH_INLINE_READ_LOCK_IRQ if !PREEMPTION 65 select ARCH_INLINE_READ_LOCK_IRQSAVE if !PREEMPTION 66 select ARCH_INLINE_READ_UNLOCK if !PREEMPTION 67 select ARCH_INLINE_READ_UNLOCK_BH if !PREEMPTION 68 select ARCH_INLINE_READ_UNLOCK_IRQ if !PREEMPTION 69 select ARCH_INLINE_READ_UNLOCK_IRQRESTORE if !PREEMPTION 70 select ARCH_INLINE_WRITE_LOCK if !PREEMPTION 71 select ARCH_INLINE_WRITE_LOCK_BH if !PREEMPTION 72 select ARCH_INLINE_WRITE_LOCK_IRQ if !PREEMPTION 73 select ARCH_INLINE_WRITE_LOCK_IRQSAVE if !PREEMPTION 74 select ARCH_INLINE_WRITE_UNLOCK if !PREEMPTION 75 select ARCH_INLINE_WRITE_UNLOCK_BH if !PREEMPTION 76 select ARCH_INLINE_WRITE_UNLOCK_IRQ if !PREEMPTION 77 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE if !PREEMPTION 78 select ARCH_INLINE_SPIN_TRYLOCK if !PREEMPTION 79 select ARCH_INLINE_SPIN_TRYLOCK_BH if !PREEMPTION 80 select ARCH_INLINE_SPIN_LOCK if !PREEMPTION 81 select ARCH_INLINE_SPIN_LOCK_BH if !PREEMPTION 82 select ARCH_INLINE_SPIN_LOCK_IRQ if !PREEMPTION 83 select ARCH_INLINE_SPIN_LOCK_IRQSAVE if !PREEMPTION 84 select ARCH_INLINE_SPIN_UNLOCK if !PREEMPTION 85 select ARCH_INLINE_SPIN_UNLOCK_BH if !PREEMPTION 86 select ARCH_INLINE_SPIN_UNLOCK_IRQ if !PREEMPTION 87 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPTION 88 select ARCH_KEEP_MEMBLOCK 89 select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 90 select ARCH_USE_CMPXCHG_LOCKREF 91 select ARCH_USE_GNU_PROPERTY 92 select ARCH_USE_MEMTEST 93 select ARCH_USE_QUEUED_RWLOCKS 94 select ARCH_USE_QUEUED_SPINLOCKS 95 select ARCH_USE_SYM_ANNOTATIONS 96 select ARCH_SUPPORTS_DEBUG_PAGEALLOC 97 select ARCH_SUPPORTS_HUGETLBFS 98 select ARCH_SUPPORTS_MEMORY_FAILURE 99 select ARCH_SUPPORTS_SHADOW_CALL_STACK if CC_HAVE_SHADOW_CALL_STACK 100 select ARCH_SUPPORTS_LTO_CLANG if CPU_LITTLE_ENDIAN 101 select ARCH_SUPPORTS_LTO_CLANG_THIN 102 select ARCH_SUPPORTS_CFI_CLANG 103 select ARCH_SUPPORTS_ATOMIC_RMW 104 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 105 select ARCH_SUPPORTS_NUMA_BALANCING 106 select ARCH_SUPPORTS_PAGE_TABLE_CHECK 107 select ARCH_SUPPORTS_PER_VMA_LOCK 108 select ARCH_SUPPORTS_HUGE_PFNMAP if TRANSPARENT_HUGEPAGE 109 select ARCH_SUPPORTS_RT 110 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 111 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT 112 select ARCH_WANT_DEFAULT_BPF_JIT 113 select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT 114 select ARCH_WANT_FRAME_POINTERS 115 select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36) 116 select ARCH_WANT_LD_ORPHAN_WARN 117 select ARCH_WANTS_EXECMEM_LATE if EXECMEM 118 select ARCH_WANTS_NO_INSTR 119 select ARCH_WANTS_THP_SWAP if ARM64_4K_PAGES 120 select ARCH_HAS_UBSAN 121 select ARM_AMBA 122 select ARM_ARCH_TIMER 123 select ARM_GIC 124 select AUDIT_ARCH_COMPAT_GENERIC 125 select ARM_GIC_V2M if PCI 126 select ARM_GIC_V3 127 select ARM_GIC_V3_ITS if PCI 128 select ARM_PSCI_FW 129 select BUILDTIME_TABLE_SORT 130 select CLONE_BACKWARDS 131 select COMMON_CLK 132 select CPU_PM if (SUSPEND || CPU_IDLE) 133 select CPUMASK_OFFSTACK if NR_CPUS > 256 134 select CRC32 135 select DCACHE_WORD_ACCESS 136 select DYNAMIC_FTRACE if FUNCTION_TRACER 137 select DMA_BOUNCE_UNALIGNED_KMALLOC 138 select DMA_DIRECT_REMAP 139 select EDAC_SUPPORT 140 select FRAME_POINTER 141 select FUNCTION_ALIGNMENT_4B 142 select FUNCTION_ALIGNMENT_8B if DYNAMIC_FTRACE_WITH_CALL_OPS 143 select GENERIC_ALLOCATOR 144 select GENERIC_ARCH_TOPOLOGY 145 select GENERIC_CLOCKEVENTS_BROADCAST 146 select GENERIC_CPU_AUTOPROBE 147 select GENERIC_CPU_DEVICES 148 select GENERIC_CPU_VULNERABILITIES 149 select GENERIC_EARLY_IOREMAP 150 select GENERIC_IDLE_POLL_SETUP 151 select GENERIC_IOREMAP 152 select GENERIC_IRQ_IPI 153 select GENERIC_IRQ_PROBE 154 select GENERIC_IRQ_SHOW 155 select GENERIC_IRQ_SHOW_LEVEL 156 select GENERIC_LIB_DEVMEM_IS_ALLOWED 157 select GENERIC_PCI_IOMAP 158 select GENERIC_PTDUMP 159 select GENERIC_SCHED_CLOCK 160 select GENERIC_SMP_IDLE_THREAD 161 select GENERIC_TIME_VSYSCALL 162 select GENERIC_GETTIMEOFDAY 163 select GENERIC_VDSO_TIME_NS 164 select HARDIRQS_SW_RESEND 165 select HAS_IOPORT 166 select HAVE_MOVE_PMD 167 select HAVE_MOVE_PUD 168 select HAVE_PCI 169 select HAVE_ACPI_APEI if (ACPI && EFI) 170 select HAVE_ALIGNED_STRUCT_PAGE 171 select HAVE_ARCH_AUDITSYSCALL 172 select HAVE_ARCH_BITREVERSE 173 select HAVE_ARCH_COMPILER_H 174 select HAVE_ARCH_HUGE_VMALLOC 175 select HAVE_ARCH_HUGE_VMAP 176 select HAVE_ARCH_JUMP_LABEL 177 select HAVE_ARCH_JUMP_LABEL_RELATIVE 178 select HAVE_ARCH_KASAN 179 select HAVE_ARCH_KASAN_VMALLOC 180 select HAVE_ARCH_KASAN_SW_TAGS 181 select HAVE_ARCH_KASAN_HW_TAGS if ARM64_MTE 182 # Some instrumentation may be unsound, hence EXPERT 183 select HAVE_ARCH_KCSAN if EXPERT 184 select HAVE_ARCH_KFENCE 185 select HAVE_ARCH_KGDB 186 select HAVE_ARCH_MMAP_RND_BITS 187 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT 188 select HAVE_ARCH_PREL32_RELOCATIONS 189 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 190 select HAVE_ARCH_SECCOMP_FILTER 191 select HAVE_ARCH_STACKLEAK 192 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 193 select HAVE_ARCH_TRACEHOOK 194 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 195 select HAVE_ARCH_VMAP_STACK 196 select HAVE_ARM_SMCCC 197 select HAVE_ASM_MODVERSIONS 198 select HAVE_EBPF_JIT 199 select HAVE_C_RECORDMCOUNT 200 select HAVE_CMPXCHG_DOUBLE 201 select HAVE_CMPXCHG_LOCAL 202 select HAVE_CONTEXT_TRACKING_USER 203 select HAVE_DEBUG_KMEMLEAK 204 select HAVE_DMA_CONTIGUOUS 205 select HAVE_DYNAMIC_FTRACE 206 select HAVE_DYNAMIC_FTRACE_WITH_ARGS \ 207 if (GCC_SUPPORTS_DYNAMIC_FTRACE_WITH_ARGS || \ 208 CLANG_SUPPORTS_DYNAMIC_FTRACE_WITH_ARGS) 209 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS \ 210 if DYNAMIC_FTRACE_WITH_ARGS && DYNAMIC_FTRACE_WITH_CALL_OPS 211 select HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS \ 212 if (DYNAMIC_FTRACE_WITH_ARGS && !CFI_CLANG && \ 213 (CC_IS_CLANG || !CC_OPTIMIZE_FOR_SIZE)) 214 select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY \ 215 if DYNAMIC_FTRACE_WITH_ARGS 216 select HAVE_SAMPLE_FTRACE_DIRECT 217 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI 218 select HAVE_EFFICIENT_UNALIGNED_ACCESS 219 select HAVE_GUP_FAST 220 select HAVE_FTRACE_MCOUNT_RECORD 221 select HAVE_FUNCTION_TRACER 222 select HAVE_FUNCTION_ERROR_INJECTION 223 select HAVE_FUNCTION_GRAPH_TRACER 224 select HAVE_FUNCTION_GRAPH_RETVAL 225 select HAVE_GCC_PLUGINS 226 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && \ 227 HW_PERF_EVENTS && HAVE_PERF_EVENTS_NMI 228 select HAVE_HW_BREAKPOINT if PERF_EVENTS 229 select HAVE_IOREMAP_PROT 230 select HAVE_IRQ_TIME_ACCOUNTING 231 select HAVE_MOD_ARCH_SPECIFIC 232 select HAVE_NMI 233 select HAVE_PERF_EVENTS 234 select HAVE_PERF_EVENTS_NMI if ARM64_PSEUDO_NMI 235 select HAVE_PERF_REGS 236 select HAVE_PERF_USER_STACK_DUMP 237 select HAVE_PREEMPT_DYNAMIC_KEY 238 select HAVE_REGS_AND_STACK_ACCESS_API 239 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 240 select HAVE_FUNCTION_ARG_ACCESS_API 241 select MMU_GATHER_RCU_TABLE_FREE 242 select HAVE_RSEQ 243 select HAVE_RUST if RUSTC_SUPPORTS_ARM64 244 select HAVE_STACKPROTECTOR 245 select HAVE_SYSCALL_TRACEPOINTS 246 select HAVE_KPROBES 247 select HAVE_KRETPROBES 248 select HAVE_GENERIC_VDSO 249 select HOTPLUG_CORE_SYNC_DEAD if HOTPLUG_CPU 250 select IRQ_DOMAIN 251 select IRQ_FORCED_THREADING 252 select KASAN_VMALLOC if KASAN 253 select LOCK_MM_AND_FIND_VMA 254 select MODULES_USE_ELF_RELA 255 select NEED_DMA_MAP_STATE 256 select NEED_SG_DMA_LENGTH 257 select OF 258 select OF_EARLY_FLATTREE 259 select PCI_DOMAINS_GENERIC if PCI 260 select PCI_ECAM if (ACPI && PCI) 261 select PCI_SYSCALL if PCI 262 select POWER_RESET 263 select POWER_SUPPLY 264 select SPARSE_IRQ 265 select SWIOTLB 266 select SYSCTL_EXCEPTION_TRACE 267 select THREAD_INFO_IN_TASK 268 select HAVE_ARCH_USERFAULTFD_MINOR if USERFAULTFD 269 select HAVE_ARCH_USERFAULTFD_WP if USERFAULTFD 270 select TRACE_IRQFLAGS_SUPPORT 271 select TRACE_IRQFLAGS_NMI_SUPPORT 272 select HAVE_SOFTIRQ_ON_OWN_STACK 273 select USER_STACKTRACE_SUPPORT 274 select VDSO_GETRANDOM 275 help 276 ARM 64-bit (AArch64) Linux support. 277 278config RUSTC_SUPPORTS_ARM64 279 def_bool y 280 depends on CPU_LITTLE_ENDIAN 281 # Shadow call stack is only supported on certain rustc versions. 282 # 283 # When using the UNWIND_PATCH_PAC_INTO_SCS option, rustc version 1.80+ is 284 # required due to use of the -Zfixed-x18 flag. 285 # 286 # Otherwise, rustc version 1.82+ is required due to use of the 287 # -Zsanitizer=shadow-call-stack flag. 288 depends on !SHADOW_CALL_STACK || RUSTC_VERSION >= 108200 || RUSTC_VERSION >= 108000 && UNWIND_PATCH_PAC_INTO_SCS 289 290config CLANG_SUPPORTS_DYNAMIC_FTRACE_WITH_ARGS 291 def_bool CC_IS_CLANG 292 # https://github.com/ClangBuiltLinux/linux/issues/1507 293 depends on AS_IS_GNU || (AS_IS_LLVM && (LD_IS_LLD || LD_VERSION >= 23600)) 294 295config GCC_SUPPORTS_DYNAMIC_FTRACE_WITH_ARGS 296 def_bool CC_IS_GCC 297 depends on $(cc-option,-fpatchable-function-entry=2) 298 299config 64BIT 300 def_bool y 301 302config MMU 303 def_bool y 304 305config ARM64_CONT_PTE_SHIFT 306 int 307 default 5 if PAGE_SIZE_64KB 308 default 7 if PAGE_SIZE_16KB 309 default 4 310 311config ARM64_CONT_PMD_SHIFT 312 int 313 default 5 if PAGE_SIZE_64KB 314 default 5 if PAGE_SIZE_16KB 315 default 4 316 317config ARCH_MMAP_RND_BITS_MIN 318 default 14 if PAGE_SIZE_64KB 319 default 16 if PAGE_SIZE_16KB 320 default 18 321 322# max bits determined by the following formula: 323# VA_BITS - PAGE_SHIFT - 3 324config ARCH_MMAP_RND_BITS_MAX 325 default 19 if ARM64_VA_BITS=36 326 default 24 if ARM64_VA_BITS=39 327 default 27 if ARM64_VA_BITS=42 328 default 30 if ARM64_VA_BITS=47 329 default 29 if ARM64_VA_BITS=48 && ARM64_64K_PAGES 330 default 31 if ARM64_VA_BITS=48 && ARM64_16K_PAGES 331 default 33 if ARM64_VA_BITS=48 332 default 14 if ARM64_64K_PAGES 333 default 16 if ARM64_16K_PAGES 334 default 18 335 336config ARCH_MMAP_RND_COMPAT_BITS_MIN 337 default 7 if ARM64_64K_PAGES 338 default 9 if ARM64_16K_PAGES 339 default 11 340 341config ARCH_MMAP_RND_COMPAT_BITS_MAX 342 default 16 343 344config NO_IOPORT_MAP 345 def_bool y if !PCI 346 347config STACKTRACE_SUPPORT 348 def_bool y 349 350config ILLEGAL_POINTER_VALUE 351 hex 352 default 0xdead000000000000 353 354config LOCKDEP_SUPPORT 355 def_bool y 356 357config GENERIC_BUG 358 def_bool y 359 depends on BUG 360 361config GENERIC_BUG_RELATIVE_POINTERS 362 def_bool y 363 depends on GENERIC_BUG 364 365config GENERIC_HWEIGHT 366 def_bool y 367 368config GENERIC_CSUM 369 def_bool y 370 371config GENERIC_CALIBRATE_DELAY 372 def_bool y 373 374config SMP 375 def_bool y 376 377config KERNEL_MODE_NEON 378 def_bool y 379 380config FIX_EARLYCON_MEM 381 def_bool y 382 383config PGTABLE_LEVELS 384 int 385 default 2 if ARM64_16K_PAGES && ARM64_VA_BITS_36 386 default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42 387 default 3 if ARM64_64K_PAGES && (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) 388 default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39 389 default 3 if ARM64_16K_PAGES && ARM64_VA_BITS_47 390 default 4 if ARM64_16K_PAGES && (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) 391 default 4 if !ARM64_64K_PAGES && ARM64_VA_BITS_48 392 default 5 if ARM64_4K_PAGES && ARM64_VA_BITS_52 393 394config ARCH_SUPPORTS_UPROBES 395 def_bool y 396 397config ARCH_PROC_KCORE_TEXT 398 def_bool y 399 400config BROKEN_GAS_INST 401 def_bool !$(as-instr,1:\n.inst 0\n.rept . - 1b\n\nnop\n.endr\n) 402 403config BUILTIN_RETURN_ADDRESS_STRIPS_PAC 404 bool 405 # Clang's __builtin_return_address() strips the PAC since 12.0.0 406 # https://github.com/llvm/llvm-project/commit/2a96f47c5ffca84cd774ad402cacd137f4bf45e2 407 default y if CC_IS_CLANG 408 # GCC's __builtin_return_address() strips the PAC since 11.1.0, 409 # and this was backported to 10.2.0, 9.4.0, 8.5.0, but not earlier 410 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94891 411 default y if CC_IS_GCC && (GCC_VERSION >= 110100) 412 default y if CC_IS_GCC && (GCC_VERSION >= 100200) && (GCC_VERSION < 110000) 413 default y if CC_IS_GCC && (GCC_VERSION >= 90400) && (GCC_VERSION < 100000) 414 default y if CC_IS_GCC && (GCC_VERSION >= 80500) && (GCC_VERSION < 90000) 415 default n 416 417config KASAN_SHADOW_OFFSET 418 hex 419 depends on KASAN_GENERIC || KASAN_SW_TAGS 420 default 0xdfff800000000000 if (ARM64_VA_BITS_48 || (ARM64_VA_BITS_52 && !ARM64_16K_PAGES)) && !KASAN_SW_TAGS 421 default 0xdfffc00000000000 if (ARM64_VA_BITS_47 || ARM64_VA_BITS_52) && ARM64_16K_PAGES && !KASAN_SW_TAGS 422 default 0xdffffe0000000000 if ARM64_VA_BITS_42 && !KASAN_SW_TAGS 423 default 0xdfffffc000000000 if ARM64_VA_BITS_39 && !KASAN_SW_TAGS 424 default 0xdffffff800000000 if ARM64_VA_BITS_36 && !KASAN_SW_TAGS 425 default 0xefff800000000000 if (ARM64_VA_BITS_48 || (ARM64_VA_BITS_52 && !ARM64_16K_PAGES)) && KASAN_SW_TAGS 426 default 0xefffc00000000000 if (ARM64_VA_BITS_47 || ARM64_VA_BITS_52) && ARM64_16K_PAGES && KASAN_SW_TAGS 427 default 0xeffffe0000000000 if ARM64_VA_BITS_42 && KASAN_SW_TAGS 428 default 0xefffffc000000000 if ARM64_VA_BITS_39 && KASAN_SW_TAGS 429 default 0xeffffff800000000 if ARM64_VA_BITS_36 && KASAN_SW_TAGS 430 default 0xffffffffffffffff 431 432config UNWIND_TABLES 433 bool 434 435source "arch/arm64/Kconfig.platforms" 436 437menu "Kernel Features" 438 439menu "ARM errata workarounds via the alternatives framework" 440 441config AMPERE_ERRATUM_AC03_CPU_38 442 bool "AmpereOne: AC03_CPU_38: Certain bits in the Virtualization Translation Control Register and Translation Control Registers do not follow RES0 semantics" 443 default y 444 help 445 This option adds an alternative code sequence to work around Ampere 446 errata AC03_CPU_38 and AC04_CPU_10 on AmpereOne. 447 448 The affected design reports FEAT_HAFDBS as not implemented in 449 ID_AA64MMFR1_EL1.HAFDBS, but (V)TCR_ELx.{HA,HD} are not RES0 450 as required by the architecture. The unadvertised HAFDBS 451 implementation suffers from an additional erratum where hardware 452 A/D updates can occur after a PTE has been marked invalid. 453 454 The workaround forces KVM to explicitly set VTCR_EL2.HA to 0, 455 which avoids enabling unadvertised hardware Access Flag management 456 at stage-2. 457 458 If unsure, say Y. 459 460config ARM64_WORKAROUND_CLEAN_CACHE 461 bool 462 463config ARM64_ERRATUM_826319 464 bool "Cortex-A53: 826319: System might deadlock if a write cannot complete until read data is accepted" 465 default y 466 select ARM64_WORKAROUND_CLEAN_CACHE 467 help 468 This option adds an alternative code sequence to work around ARM 469 erratum 826319 on Cortex-A53 parts up to r0p2 with an AMBA 4 ACE or 470 AXI master interface and an L2 cache. 471 472 If a Cortex-A53 uses an AMBA AXI4 ACE interface to other processors 473 and is unable to accept a certain write via this interface, it will 474 not progress on read data presented on the read data channel and the 475 system can deadlock. 476 477 The workaround promotes data cache clean instructions to 478 data cache clean-and-invalidate. 479 Please note that this does not necessarily enable the workaround, 480 as it depends on the alternative framework, which will only patch 481 the kernel if an affected CPU is detected. 482 483 If unsure, say Y. 484 485config ARM64_ERRATUM_827319 486 bool "Cortex-A53: 827319: Data cache clean instructions might cause overlapping transactions to the interconnect" 487 default y 488 select ARM64_WORKAROUND_CLEAN_CACHE 489 help 490 This option adds an alternative code sequence to work around ARM 491 erratum 827319 on Cortex-A53 parts up to r0p2 with an AMBA 5 CHI 492 master interface and an L2 cache. 493 494 Under certain conditions this erratum can cause a clean line eviction 495 to occur at the same time as another transaction to the same address 496 on the AMBA 5 CHI interface, which can cause data corruption if the 497 interconnect reorders the two transactions. 498 499 The workaround promotes data cache clean instructions to 500 data cache clean-and-invalidate. 501 Please note that this does not necessarily enable the workaround, 502 as it depends on the alternative framework, which will only patch 503 the kernel if an affected CPU is detected. 504 505 If unsure, say Y. 506 507config ARM64_ERRATUM_824069 508 bool "Cortex-A53: 824069: Cache line might not be marked as clean after a CleanShared snoop" 509 default y 510 select ARM64_WORKAROUND_CLEAN_CACHE 511 help 512 This option adds an alternative code sequence to work around ARM 513 erratum 824069 on Cortex-A53 parts up to r0p2 when it is connected 514 to a coherent interconnect. 515 516 If a Cortex-A53 processor is executing a store or prefetch for 517 write instruction at the same time as a processor in another 518 cluster is executing a cache maintenance operation to the same 519 address, then this erratum might cause a clean cache line to be 520 incorrectly marked as dirty. 521 522 The workaround promotes data cache clean instructions to 523 data cache clean-and-invalidate. 524 Please note that this option does not necessarily enable the 525 workaround, as it depends on the alternative framework, which will 526 only patch the kernel if an affected CPU is detected. 527 528 If unsure, say Y. 529 530config ARM64_ERRATUM_819472 531 bool "Cortex-A53: 819472: Store exclusive instructions might cause data corruption" 532 default y 533 select ARM64_WORKAROUND_CLEAN_CACHE 534 help 535 This option adds an alternative code sequence to work around ARM 536 erratum 819472 on Cortex-A53 parts up to r0p1 with an L2 cache 537 present when it is connected to a coherent interconnect. 538 539 If the processor is executing a load and store exclusive sequence at 540 the same time as a processor in another cluster is executing a cache 541 maintenance operation to the same address, then this erratum might 542 cause data corruption. 543 544 The workaround promotes data cache clean instructions to 545 data cache clean-and-invalidate. 546 Please note that this does not necessarily enable the workaround, 547 as it depends on the alternative framework, which will only patch 548 the kernel if an affected CPU is detected. 549 550 If unsure, say Y. 551 552config ARM64_ERRATUM_832075 553 bool "Cortex-A57: 832075: possible deadlock on mixing exclusive memory accesses with device loads" 554 default y 555 help 556 This option adds an alternative code sequence to work around ARM 557 erratum 832075 on Cortex-A57 parts up to r1p2. 558 559 Affected Cortex-A57 parts might deadlock when exclusive load/store 560 instructions to Write-Back memory are mixed with Device loads. 561 562 The workaround is to promote device loads to use Load-Acquire 563 semantics. 564 Please note that this does not necessarily enable the workaround, 565 as it depends on the alternative framework, which will only patch 566 the kernel if an affected CPU is detected. 567 568 If unsure, say Y. 569 570config ARM64_ERRATUM_834220 571 bool "Cortex-A57: 834220: Stage 2 translation fault might be incorrectly reported in presence of a Stage 1 fault (rare)" 572 depends on KVM 573 help 574 This option adds an alternative code sequence to work around ARM 575 erratum 834220 on Cortex-A57 parts up to r1p2. 576 577 Affected Cortex-A57 parts might report a Stage 2 translation 578 fault as the result of a Stage 1 fault for load crossing a 579 page boundary when there is a permission or device memory 580 alignment fault at Stage 1 and a translation fault at Stage 2. 581 582 The workaround is to verify that the Stage 1 translation 583 doesn't generate a fault before handling the Stage 2 fault. 584 Please note that this does not necessarily enable the workaround, 585 as it depends on the alternative framework, which will only patch 586 the kernel if an affected CPU is detected. 587 588 If unsure, say N. 589 590config ARM64_ERRATUM_1742098 591 bool "Cortex-A57/A72: 1742098: ELR recorded incorrectly on interrupt taken between cryptographic instructions in a sequence" 592 depends on COMPAT 593 default y 594 help 595 This option removes the AES hwcap for aarch32 user-space to 596 workaround erratum 1742098 on Cortex-A57 and Cortex-A72. 597 598 Affected parts may corrupt the AES state if an interrupt is 599 taken between a pair of AES instructions. These instructions 600 are only present if the cryptography extensions are present. 601 All software should have a fallback implementation for CPUs 602 that don't implement the cryptography extensions. 603 604 If unsure, say Y. 605 606config ARM64_ERRATUM_845719 607 bool "Cortex-A53: 845719: a load might read incorrect data" 608 depends on COMPAT 609 default y 610 help 611 This option adds an alternative code sequence to work around ARM 612 erratum 845719 on Cortex-A53 parts up to r0p4. 613 614 When running a compat (AArch32) userspace on an affected Cortex-A53 615 part, a load at EL0 from a virtual address that matches the bottom 32 616 bits of the virtual address used by a recent load at (AArch64) EL1 617 might return incorrect data. 618 619 The workaround is to write the contextidr_el1 register on exception 620 return to a 32-bit task. 621 Please note that this does not necessarily enable the workaround, 622 as it depends on the alternative framework, which will only patch 623 the kernel if an affected CPU is detected. 624 625 If unsure, say Y. 626 627config ARM64_ERRATUM_843419 628 bool "Cortex-A53: 843419: A load or store might access an incorrect address" 629 default y 630 help 631 This option links the kernel with '--fix-cortex-a53-843419' and 632 enables PLT support to replace certain ADRP instructions, which can 633 cause subsequent memory accesses to use an incorrect address on 634 Cortex-A53 parts up to r0p4. 635 636 If unsure, say Y. 637 638config ARM64_LD_HAS_FIX_ERRATUM_843419 639 def_bool $(ld-option,--fix-cortex-a53-843419) 640 641config ARM64_ERRATUM_1024718 642 bool "Cortex-A55: 1024718: Update of DBM/AP bits without break before make might result in incorrect update" 643 default y 644 help 645 This option adds a workaround for ARM Cortex-A55 Erratum 1024718. 646 647 Affected Cortex-A55 cores (all revisions) could cause incorrect 648 update of the hardware dirty bit when the DBM/AP bits are updated 649 without a break-before-make. The workaround is to disable the usage 650 of hardware DBM locally on the affected cores. CPUs not affected by 651 this erratum will continue to use the feature. 652 653 If unsure, say Y. 654 655config ARM64_ERRATUM_1418040 656 bool "Cortex-A76/Neoverse-N1: MRC read following MRRC read of specific Generic Timer in AArch32 might give incorrect result" 657 default y 658 depends on COMPAT 659 help 660 This option adds a workaround for ARM Cortex-A76/Neoverse-N1 661 errata 1188873 and 1418040. 662 663 Affected Cortex-A76/Neoverse-N1 cores (r0p0 to r3p1) could 664 cause register corruption when accessing the timer registers 665 from AArch32 userspace. 666 667 If unsure, say Y. 668 669config ARM64_WORKAROUND_SPECULATIVE_AT 670 bool 671 672config ARM64_ERRATUM_1165522 673 bool "Cortex-A76: 1165522: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation" 674 default y 675 select ARM64_WORKAROUND_SPECULATIVE_AT 676 help 677 This option adds a workaround for ARM Cortex-A76 erratum 1165522. 678 679 Affected Cortex-A76 cores (r0p0, r1p0, r2p0) could end-up with 680 corrupted TLBs by speculating an AT instruction during a guest 681 context switch. 682 683 If unsure, say Y. 684 685config ARM64_ERRATUM_1319367 686 bool "Cortex-A57/A72: 1319537: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation" 687 default y 688 select ARM64_WORKAROUND_SPECULATIVE_AT 689 help 690 This option adds work arounds for ARM Cortex-A57 erratum 1319537 691 and A72 erratum 1319367 692 693 Cortex-A57 and A72 cores could end-up with corrupted TLBs by 694 speculating an AT instruction during a guest context switch. 695 696 If unsure, say Y. 697 698config ARM64_ERRATUM_1530923 699 bool "Cortex-A55: 1530923: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation" 700 default y 701 select ARM64_WORKAROUND_SPECULATIVE_AT 702 help 703 This option adds a workaround for ARM Cortex-A55 erratum 1530923. 704 705 Affected Cortex-A55 cores (r0p0, r0p1, r1p0, r2p0) could end-up with 706 corrupted TLBs by speculating an AT instruction during a guest 707 context switch. 708 709 If unsure, say Y. 710 711config ARM64_WORKAROUND_REPEAT_TLBI 712 bool 713 714config ARM64_ERRATUM_2441007 715 bool "Cortex-A55: Completion of affected memory accesses might not be guaranteed by completion of a TLBI (rare)" 716 select ARM64_WORKAROUND_REPEAT_TLBI 717 help 718 This option adds a workaround for ARM Cortex-A55 erratum #2441007. 719 720 Under very rare circumstances, affected Cortex-A55 CPUs 721 may not handle a race between a break-before-make sequence on one 722 CPU, and another CPU accessing the same page. This could allow a 723 store to a page that has been unmapped. 724 725 Work around this by adding the affected CPUs to the list that needs 726 TLB sequences to be done twice. 727 728 If unsure, say N. 729 730config ARM64_ERRATUM_1286807 731 bool "Cortex-A76: Modification of the translation table for a virtual address might lead to read-after-read ordering violation (rare)" 732 select ARM64_WORKAROUND_REPEAT_TLBI 733 help 734 This option adds a workaround for ARM Cortex-A76 erratum 1286807. 735 736 On the affected Cortex-A76 cores (r0p0 to r3p0), if a virtual 737 address for a cacheable mapping of a location is being 738 accessed by a core while another core is remapping the virtual 739 address to a new physical page using the recommended 740 break-before-make sequence, then under very rare circumstances 741 TLBI+DSB completes before a read using the translation being 742 invalidated has been observed by other observers. The 743 workaround repeats the TLBI+DSB operation. 744 745 If unsure, say N. 746 747config ARM64_ERRATUM_1463225 748 bool "Cortex-A76: Software Step might prevent interrupt recognition" 749 default y 750 help 751 This option adds a workaround for Arm Cortex-A76 erratum 1463225. 752 753 On the affected Cortex-A76 cores (r0p0 to r3p1), software stepping 754 of a system call instruction (SVC) can prevent recognition of 755 subsequent interrupts when software stepping is disabled in the 756 exception handler of the system call and either kernel debugging 757 is enabled or VHE is in use. 758 759 Work around the erratum by triggering a dummy step exception 760 when handling a system call from a task that is being stepped 761 in a VHE configuration of the kernel. 762 763 If unsure, say Y. 764 765config ARM64_ERRATUM_1542419 766 bool "Neoverse-N1: workaround mis-ordering of instruction fetches (rare)" 767 help 768 This option adds a workaround for ARM Neoverse-N1 erratum 769 1542419. 770 771 Affected Neoverse-N1 cores could execute a stale instruction when 772 modified by another CPU. The workaround depends on a firmware 773 counterpart. 774 775 Workaround the issue by hiding the DIC feature from EL0. This 776 forces user-space to perform cache maintenance. 777 778 If unsure, say N. 779 780config ARM64_ERRATUM_1508412 781 bool "Cortex-A77: 1508412: workaround deadlock on sequence of NC/Device load and store exclusive or PAR read" 782 default y 783 help 784 This option adds a workaround for Arm Cortex-A77 erratum 1508412. 785 786 Affected Cortex-A77 cores (r0p0, r1p0) could deadlock on a sequence 787 of a store-exclusive or read of PAR_EL1 and a load with device or 788 non-cacheable memory attributes. The workaround depends on a firmware 789 counterpart. 790 791 KVM guests must also have the workaround implemented or they can 792 deadlock the system. 793 794 Work around the issue by inserting DMB SY barriers around PAR_EL1 795 register reads and warning KVM users. The DMB barrier is sufficient 796 to prevent a speculative PAR_EL1 read. 797 798 If unsure, say Y. 799 800config ARM64_WORKAROUND_TRBE_OVERWRITE_FILL_MODE 801 bool 802 803config ARM64_ERRATUM_2051678 804 bool "Cortex-A510: 2051678: disable Hardware Update of the page table dirty bit" 805 default y 806 help 807 This options adds the workaround for ARM Cortex-A510 erratum ARM64_ERRATUM_2051678. 808 Affected Cortex-A510 might not respect the ordering rules for 809 hardware update of the page table's dirty bit. The workaround 810 is to not enable the feature on affected CPUs. 811 812 If unsure, say Y. 813 814config ARM64_ERRATUM_2077057 815 bool "Cortex-A510: 2077057: workaround software-step corrupting SPSR_EL2" 816 default y 817 help 818 This option adds the workaround for ARM Cortex-A510 erratum 2077057. 819 Affected Cortex-A510 may corrupt SPSR_EL2 when the a step exception is 820 expected, but a Pointer Authentication trap is taken instead. The 821 erratum causes SPSR_EL1 to be copied to SPSR_EL2, which could allow 822 EL1 to cause a return to EL2 with a guest controlled ELR_EL2. 823 824 This can only happen when EL2 is stepping EL1. 825 826 When these conditions occur, the SPSR_EL2 value is unchanged from the 827 previous guest entry, and can be restored from the in-memory copy. 828 829 If unsure, say Y. 830 831config ARM64_ERRATUM_2658417 832 bool "Cortex-A510: 2658417: remove BF16 support due to incorrect result" 833 default y 834 help 835 This option adds the workaround for ARM Cortex-A510 erratum 2658417. 836 Affected Cortex-A510 (r0p0 to r1p1) may produce the wrong result for 837 BFMMLA or VMMLA instructions in rare circumstances when a pair of 838 A510 CPUs are using shared neon hardware. As the sharing is not 839 discoverable by the kernel, hide the BF16 HWCAP to indicate that 840 user-space should not be using these instructions. 841 842 If unsure, say Y. 843 844config ARM64_ERRATUM_2119858 845 bool "Cortex-A710/X2: 2119858: workaround TRBE overwriting trace data in FILL mode" 846 default y 847 depends on CORESIGHT_TRBE 848 select ARM64_WORKAROUND_TRBE_OVERWRITE_FILL_MODE 849 help 850 This option adds the workaround for ARM Cortex-A710/X2 erratum 2119858. 851 852 Affected Cortex-A710/X2 cores could overwrite up to 3 cache lines of trace 853 data at the base of the buffer (pointed to by TRBASER_EL1) in FILL mode in 854 the event of a WRAP event. 855 856 Work around the issue by always making sure we move the TRBPTR_EL1 by 857 256 bytes before enabling the buffer and filling the first 256 bytes of 858 the buffer with ETM ignore packets upon disabling. 859 860 If unsure, say Y. 861 862config ARM64_ERRATUM_2139208 863 bool "Neoverse-N2: 2139208: workaround TRBE overwriting trace data in FILL mode" 864 default y 865 depends on CORESIGHT_TRBE 866 select ARM64_WORKAROUND_TRBE_OVERWRITE_FILL_MODE 867 help 868 This option adds the workaround for ARM Neoverse-N2 erratum 2139208. 869 870 Affected Neoverse-N2 cores could overwrite up to 3 cache lines of trace 871 data at the base of the buffer (pointed to by TRBASER_EL1) in FILL mode in 872 the event of a WRAP event. 873 874 Work around the issue by always making sure we move the TRBPTR_EL1 by 875 256 bytes before enabling the buffer and filling the first 256 bytes of 876 the buffer with ETM ignore packets upon disabling. 877 878 If unsure, say Y. 879 880config ARM64_WORKAROUND_TSB_FLUSH_FAILURE 881 bool 882 883config ARM64_ERRATUM_2054223 884 bool "Cortex-A710: 2054223: workaround TSB instruction failing to flush trace" 885 default y 886 select ARM64_WORKAROUND_TSB_FLUSH_FAILURE 887 help 888 Enable workaround for ARM Cortex-A710 erratum 2054223 889 890 Affected cores may fail to flush the trace data on a TSB instruction, when 891 the PE is in trace prohibited state. This will cause losing a few bytes 892 of the trace cached. 893 894 Workaround is to issue two TSB consecutively on affected cores. 895 896 If unsure, say Y. 897 898config ARM64_ERRATUM_2067961 899 bool "Neoverse-N2: 2067961: workaround TSB instruction failing to flush trace" 900 default y 901 select ARM64_WORKAROUND_TSB_FLUSH_FAILURE 902 help 903 Enable workaround for ARM Neoverse-N2 erratum 2067961 904 905 Affected cores may fail to flush the trace data on a TSB instruction, when 906 the PE is in trace prohibited state. This will cause losing a few bytes 907 of the trace cached. 908 909 Workaround is to issue two TSB consecutively on affected cores. 910 911 If unsure, say Y. 912 913config ARM64_WORKAROUND_TRBE_WRITE_OUT_OF_RANGE 914 bool 915 916config ARM64_ERRATUM_2253138 917 bool "Neoverse-N2: 2253138: workaround TRBE writing to address out-of-range" 918 depends on CORESIGHT_TRBE 919 default y 920 select ARM64_WORKAROUND_TRBE_WRITE_OUT_OF_RANGE 921 help 922 This option adds the workaround for ARM Neoverse-N2 erratum 2253138. 923 924 Affected Neoverse-N2 cores might write to an out-of-range address, not reserved 925 for TRBE. Under some conditions, the TRBE might generate a write to the next 926 virtually addressed page following the last page of the TRBE address space 927 (i.e., the TRBLIMITR_EL1.LIMIT), instead of wrapping around to the base. 928 929 Work around this in the driver by always making sure that there is a 930 page beyond the TRBLIMITR_EL1.LIMIT, within the space allowed for the TRBE. 931 932 If unsure, say Y. 933 934config ARM64_ERRATUM_2224489 935 bool "Cortex-A710/X2: 2224489: workaround TRBE writing to address out-of-range" 936 depends on CORESIGHT_TRBE 937 default y 938 select ARM64_WORKAROUND_TRBE_WRITE_OUT_OF_RANGE 939 help 940 This option adds the workaround for ARM Cortex-A710/X2 erratum 2224489. 941 942 Affected Cortex-A710/X2 cores might write to an out-of-range address, not reserved 943 for TRBE. Under some conditions, the TRBE might generate a write to the next 944 virtually addressed page following the last page of the TRBE address space 945 (i.e., the TRBLIMITR_EL1.LIMIT), instead of wrapping around to the base. 946 947 Work around this in the driver by always making sure that there is a 948 page beyond the TRBLIMITR_EL1.LIMIT, within the space allowed for the TRBE. 949 950 If unsure, say Y. 951 952config ARM64_ERRATUM_2441009 953 bool "Cortex-A510: Completion of affected memory accesses might not be guaranteed by completion of a TLBI (rare)" 954 select ARM64_WORKAROUND_REPEAT_TLBI 955 help 956 This option adds a workaround for ARM Cortex-A510 erratum #2441009. 957 958 Under very rare circumstances, affected Cortex-A510 CPUs 959 may not handle a race between a break-before-make sequence on one 960 CPU, and another CPU accessing the same page. This could allow a 961 store to a page that has been unmapped. 962 963 Work around this by adding the affected CPUs to the list that needs 964 TLB sequences to be done twice. 965 966 If unsure, say N. 967 968config ARM64_ERRATUM_2064142 969 bool "Cortex-A510: 2064142: workaround TRBE register writes while disabled" 970 depends on CORESIGHT_TRBE 971 default y 972 help 973 This option adds the workaround for ARM Cortex-A510 erratum 2064142. 974 975 Affected Cortex-A510 core might fail to write into system registers after the 976 TRBE has been disabled. Under some conditions after the TRBE has been disabled 977 writes into TRBE registers TRBLIMITR_EL1, TRBPTR_EL1, TRBBASER_EL1, TRBSR_EL1, 978 and TRBTRG_EL1 will be ignored and will not be effected. 979 980 Work around this in the driver by executing TSB CSYNC and DSB after collection 981 is stopped and before performing a system register write to one of the affected 982 registers. 983 984 If unsure, say Y. 985 986config ARM64_ERRATUM_2038923 987 bool "Cortex-A510: 2038923: workaround TRBE corruption with enable" 988 depends on CORESIGHT_TRBE 989 default y 990 help 991 This option adds the workaround for ARM Cortex-A510 erratum 2038923. 992 993 Affected Cortex-A510 core might cause an inconsistent view on whether trace is 994 prohibited within the CPU. As a result, the trace buffer or trace buffer state 995 might be corrupted. This happens after TRBE buffer has been enabled by setting 996 TRBLIMITR_EL1.E, followed by just a single context synchronization event before 997 execution changes from a context, in which trace is prohibited to one where it 998 isn't, or vice versa. In these mentioned conditions, the view of whether trace 999 is prohibited is inconsistent between parts of the CPU, and the trace buffer or 1000 the trace buffer state might be corrupted. 1001 1002 Work around this in the driver by preventing an inconsistent view of whether the 1003 trace is prohibited or not based on TRBLIMITR_EL1.E by immediately following a 1004 change to TRBLIMITR_EL1.E with at least one ISB instruction before an ERET, or 1005 two ISB instructions if no ERET is to take place. 1006 1007 If unsure, say Y. 1008 1009config ARM64_ERRATUM_1902691 1010 bool "Cortex-A510: 1902691: workaround TRBE trace corruption" 1011 depends on CORESIGHT_TRBE 1012 default y 1013 help 1014 This option adds the workaround for ARM Cortex-A510 erratum 1902691. 1015 1016 Affected Cortex-A510 core might cause trace data corruption, when being written 1017 into the memory. Effectively TRBE is broken and hence cannot be used to capture 1018 trace data. 1019 1020 Work around this problem in the driver by just preventing TRBE initialization on 1021 affected cpus. The firmware must have disabled the access to TRBE for the kernel 1022 on such implementations. This will cover the kernel for any firmware that doesn't 1023 do this already. 1024 1025 If unsure, say Y. 1026 1027config ARM64_ERRATUM_2457168 1028 bool "Cortex-A510: 2457168: workaround for AMEVCNTR01 incrementing incorrectly" 1029 depends on ARM64_AMU_EXTN 1030 default y 1031 help 1032 This option adds the workaround for ARM Cortex-A510 erratum 2457168. 1033 1034 The AMU counter AMEVCNTR01 (constant counter) should increment at the same rate 1035 as the system counter. On affected Cortex-A510 cores AMEVCNTR01 increments 1036 incorrectly giving a significantly higher output value. 1037 1038 Work around this problem by returning 0 when reading the affected counter in 1039 key locations that results in disabling all users of this counter. This effect 1040 is the same to firmware disabling affected counters. 1041 1042 If unsure, say Y. 1043 1044config ARM64_ERRATUM_2645198 1045 bool "Cortex-A715: 2645198: Workaround possible [ESR|FAR]_ELx corruption" 1046 default y 1047 help 1048 This option adds the workaround for ARM Cortex-A715 erratum 2645198. 1049 1050 If a Cortex-A715 cpu sees a page mapping permissions change from executable 1051 to non-executable, it may corrupt the ESR_ELx and FAR_ELx registers on the 1052 next instruction abort caused by permission fault. 1053 1054 Only user-space does executable to non-executable permission transition via 1055 mprotect() system call. Workaround the problem by doing a break-before-make 1056 TLB invalidation, for all changes to executable user space mappings. 1057 1058 If unsure, say Y. 1059 1060config ARM64_WORKAROUND_SPECULATIVE_UNPRIV_LOAD 1061 bool 1062 1063config ARM64_ERRATUM_2966298 1064 bool "Cortex-A520: 2966298: workaround for speculatively executed unprivileged load" 1065 select ARM64_WORKAROUND_SPECULATIVE_UNPRIV_LOAD 1066 default y 1067 help 1068 This option adds the workaround for ARM Cortex-A520 erratum 2966298. 1069 1070 On an affected Cortex-A520 core, a speculatively executed unprivileged 1071 load might leak data from a privileged level via a cache side channel. 1072 1073 Work around this problem by executing a TLBI before returning to EL0. 1074 1075 If unsure, say Y. 1076 1077config ARM64_ERRATUM_3117295 1078 bool "Cortex-A510: 3117295: workaround for speculatively executed unprivileged load" 1079 select ARM64_WORKAROUND_SPECULATIVE_UNPRIV_LOAD 1080 default y 1081 help 1082 This option adds the workaround for ARM Cortex-A510 erratum 3117295. 1083 1084 On an affected Cortex-A510 core, a speculatively executed unprivileged 1085 load might leak data from a privileged level via a cache side channel. 1086 1087 Work around this problem by executing a TLBI before returning to EL0. 1088 1089 If unsure, say Y. 1090 1091config ARM64_ERRATUM_3194386 1092 bool "Cortex-*/Neoverse-*: workaround for MSR SSBS not self-synchronizing" 1093 default y 1094 help 1095 This option adds the workaround for the following errata: 1096 1097 * ARM Cortex-A76 erratum 3324349 1098 * ARM Cortex-A77 erratum 3324348 1099 * ARM Cortex-A78 erratum 3324344 1100 * ARM Cortex-A78C erratum 3324346 1101 * ARM Cortex-A78C erratum 3324347 1102 * ARM Cortex-A710 erratam 3324338 1103 * ARM Cortex-A715 errartum 3456084 1104 * ARM Cortex-A720 erratum 3456091 1105 * ARM Cortex-A725 erratum 3456106 1106 * ARM Cortex-X1 erratum 3324344 1107 * ARM Cortex-X1C erratum 3324346 1108 * ARM Cortex-X2 erratum 3324338 1109 * ARM Cortex-X3 erratum 3324335 1110 * ARM Cortex-X4 erratum 3194386 1111 * ARM Cortex-X925 erratum 3324334 1112 * ARM Neoverse-N1 erratum 3324349 1113 * ARM Neoverse N2 erratum 3324339 1114 * ARM Neoverse-N3 erratum 3456111 1115 * ARM Neoverse-V1 erratum 3324341 1116 * ARM Neoverse V2 erratum 3324336 1117 * ARM Neoverse-V3 erratum 3312417 1118 1119 On affected cores "MSR SSBS, #0" instructions may not affect 1120 subsequent speculative instructions, which may permit unexepected 1121 speculative store bypassing. 1122 1123 Work around this problem by placing a Speculation Barrier (SB) or 1124 Instruction Synchronization Barrier (ISB) after kernel changes to 1125 SSBS. The presence of the SSBS special-purpose register is hidden 1126 from hwcaps and EL0 reads of ID_AA64PFR1_EL1, such that userspace 1127 will use the PR_SPEC_STORE_BYPASS prctl to change SSBS. 1128 1129 If unsure, say Y. 1130 1131config CAVIUM_ERRATUM_22375 1132 bool "Cavium erratum 22375, 24313" 1133 default y 1134 help 1135 Enable workaround for errata 22375 and 24313. 1136 1137 This implements two gicv3-its errata workarounds for ThunderX. Both 1138 with a small impact affecting only ITS table allocation. 1139 1140 erratum 22375: only alloc 8MB table size 1141 erratum 24313: ignore memory access type 1142 1143 The fixes are in ITS initialization and basically ignore memory access 1144 type and table size provided by the TYPER and BASER registers. 1145 1146 If unsure, say Y. 1147 1148config CAVIUM_ERRATUM_23144 1149 bool "Cavium erratum 23144: ITS SYNC hang on dual socket system" 1150 depends on NUMA 1151 default y 1152 help 1153 ITS SYNC command hang for cross node io and collections/cpu mapping. 1154 1155 If unsure, say Y. 1156 1157config CAVIUM_ERRATUM_23154 1158 bool "Cavium errata 23154 and 38545: GICv3 lacks HW synchronisation" 1159 default y 1160 help 1161 The ThunderX GICv3 implementation requires a modified version for 1162 reading the IAR status to ensure data synchronization 1163 (access to icc_iar1_el1 is not sync'ed before and after). 1164 1165 It also suffers from erratum 38545 (also present on Marvell's 1166 OcteonTX and OcteonTX2), resulting in deactivated interrupts being 1167 spuriously presented to the CPU interface. 1168 1169 If unsure, say Y. 1170 1171config CAVIUM_ERRATUM_27456 1172 bool "Cavium erratum 27456: Broadcast TLBI instructions may cause icache corruption" 1173 default y 1174 help 1175 On ThunderX T88 pass 1.x through 2.1 parts, broadcast TLBI 1176 instructions may cause the icache to become corrupted if it 1177 contains data for a non-current ASID. The fix is to 1178 invalidate the icache when changing the mm context. 1179 1180 If unsure, say Y. 1181 1182config CAVIUM_ERRATUM_30115 1183 bool "Cavium erratum 30115: Guest may disable interrupts in host" 1184 default y 1185 help 1186 On ThunderX T88 pass 1.x through 2.2, T81 pass 1.0 through 1187 1.2, and T83 Pass 1.0, KVM guest execution may disable 1188 interrupts in host. Trapping both GICv3 group-0 and group-1 1189 accesses sidesteps the issue. 1190 1191 If unsure, say Y. 1192 1193config CAVIUM_TX2_ERRATUM_219 1194 bool "Cavium ThunderX2 erratum 219: PRFM between TTBR change and ISB fails" 1195 default y 1196 help 1197 On Cavium ThunderX2, a load, store or prefetch instruction between a 1198 TTBR update and the corresponding context synchronizing operation can 1199 cause a spurious Data Abort to be delivered to any hardware thread in 1200 the CPU core. 1201 1202 Work around the issue by avoiding the problematic code sequence and 1203 trapping KVM guest TTBRx_EL1 writes to EL2 when SMT is enabled. The 1204 trap handler performs the corresponding register access, skips the 1205 instruction and ensures context synchronization by virtue of the 1206 exception return. 1207 1208 If unsure, say Y. 1209 1210config FUJITSU_ERRATUM_010001 1211 bool "Fujitsu-A64FX erratum E#010001: Undefined fault may occur wrongly" 1212 default y 1213 help 1214 This option adds a workaround for Fujitsu-A64FX erratum E#010001. 1215 On some variants of the Fujitsu-A64FX cores ver(1.0, 1.1), memory 1216 accesses may cause undefined fault (Data abort, DFSC=0b111111). 1217 This fault occurs under a specific hardware condition when a 1218 load/store instruction performs an address translation using: 1219 case-1 TTBR0_EL1 with TCR_EL1.NFD0 == 1. 1220 case-2 TTBR0_EL2 with TCR_EL2.NFD0 == 1. 1221 case-3 TTBR1_EL1 with TCR_EL1.NFD1 == 1. 1222 case-4 TTBR1_EL2 with TCR_EL2.NFD1 == 1. 1223 1224 The workaround is to ensure these bits are clear in TCR_ELx. 1225 The workaround only affects the Fujitsu-A64FX. 1226 1227 If unsure, say Y. 1228 1229config HISILICON_ERRATUM_161600802 1230 bool "Hip07 161600802: Erroneous redistributor VLPI base" 1231 default y 1232 help 1233 The HiSilicon Hip07 SoC uses the wrong redistributor base 1234 when issued ITS commands such as VMOVP and VMAPP, and requires 1235 a 128kB offset to be applied to the target address in this commands. 1236 1237 If unsure, say Y. 1238 1239config HISILICON_ERRATUM_162100801 1240 bool "Hip09 162100801 erratum support" 1241 default y 1242 help 1243 When enabling GICv4.1 in hip09, VMAPP will fail to clear some caches 1244 during unmapping operation, which will cause some vSGIs lost. 1245 To fix the issue, invalidate related vPE cache through GICR_INVALLR 1246 after VMOVP. 1247 1248 If unsure, say Y. 1249 1250config QCOM_FALKOR_ERRATUM_1003 1251 bool "Falkor E1003: Incorrect translation due to ASID change" 1252 default y 1253 help 1254 On Falkor v1, an incorrect ASID may be cached in the TLB when ASID 1255 and BADDR are changed together in TTBRx_EL1. Since we keep the ASID 1256 in TTBR1_EL1, this situation only occurs in the entry trampoline and 1257 then only for entries in the walk cache, since the leaf translation 1258 is unchanged. Work around the erratum by invalidating the walk cache 1259 entries for the trampoline before entering the kernel proper. 1260 1261config QCOM_FALKOR_ERRATUM_1009 1262 bool "Falkor E1009: Prematurely complete a DSB after a TLBI" 1263 default y 1264 select ARM64_WORKAROUND_REPEAT_TLBI 1265 help 1266 On Falkor v1, the CPU may prematurely complete a DSB following a 1267 TLBI xxIS invalidate maintenance operation. Repeat the TLBI operation 1268 one more time to fix the issue. 1269 1270 If unsure, say Y. 1271 1272config QCOM_QDF2400_ERRATUM_0065 1273 bool "QDF2400 E0065: Incorrect GITS_TYPER.ITT_Entry_size" 1274 default y 1275 help 1276 On Qualcomm Datacenter Technologies QDF2400 SoC, ITS hardware reports 1277 ITE size incorrectly. The GITS_TYPER.ITT_Entry_size field should have 1278 been indicated as 16Bytes (0xf), not 8Bytes (0x7). 1279 1280 If unsure, say Y. 1281 1282config QCOM_FALKOR_ERRATUM_E1041 1283 bool "Falkor E1041: Speculative instruction fetches might cause errant memory access" 1284 default y 1285 help 1286 Falkor CPU may speculatively fetch instructions from an improper 1287 memory location when MMU translation is changed from SCTLR_ELn[M]=1 1288 to SCTLR_ELn[M]=0. Prefix an ISB instruction to fix the problem. 1289 1290 If unsure, say Y. 1291 1292config NVIDIA_CARMEL_CNP_ERRATUM 1293 bool "NVIDIA Carmel CNP: CNP on Carmel semantically different than ARM cores" 1294 default y 1295 help 1296 If CNP is enabled on Carmel cores, non-sharable TLBIs on a core will not 1297 invalidate shared TLB entries installed by a different core, as it would 1298 on standard ARM cores. 1299 1300 If unsure, say Y. 1301 1302config ROCKCHIP_ERRATUM_3588001 1303 bool "Rockchip 3588001: GIC600 can not support shareability attributes" 1304 default y 1305 help 1306 The Rockchip RK3588 GIC600 SoC integration does not support ACE/ACE-lite. 1307 This means, that its sharability feature may not be used, even though it 1308 is supported by the IP itself. 1309 1310 If unsure, say Y. 1311 1312config SOCIONEXT_SYNQUACER_PREITS 1313 bool "Socionext Synquacer: Workaround for GICv3 pre-ITS" 1314 default y 1315 help 1316 Socionext Synquacer SoCs implement a separate h/w block to generate 1317 MSI doorbell writes with non-zero values for the device ID. 1318 1319 If unsure, say Y. 1320 1321endmenu # "ARM errata workarounds via the alternatives framework" 1322 1323choice 1324 prompt "Page size" 1325 default ARM64_4K_PAGES 1326 help 1327 Page size (translation granule) configuration. 1328 1329config ARM64_4K_PAGES 1330 bool "4KB" 1331 select HAVE_PAGE_SIZE_4KB 1332 help 1333 This feature enables 4KB pages support. 1334 1335config ARM64_16K_PAGES 1336 bool "16KB" 1337 select HAVE_PAGE_SIZE_16KB 1338 help 1339 The system will use 16KB pages support. AArch32 emulation 1340 requires applications compiled with 16K (or a multiple of 16K) 1341 aligned segments. 1342 1343config ARM64_64K_PAGES 1344 bool "64KB" 1345 select HAVE_PAGE_SIZE_64KB 1346 help 1347 This feature enables 64KB pages support (4KB by default) 1348 allowing only two levels of page tables and faster TLB 1349 look-up. AArch32 emulation requires applications compiled 1350 with 64K aligned segments. 1351 1352endchoice 1353 1354choice 1355 prompt "Virtual address space size" 1356 default ARM64_VA_BITS_52 1357 help 1358 Allows choosing one of multiple possible virtual address 1359 space sizes. The level of translation table is determined by 1360 a combination of page size and virtual address space size. 1361 1362config ARM64_VA_BITS_36 1363 bool "36-bit" if EXPERT 1364 depends on PAGE_SIZE_16KB 1365 1366config ARM64_VA_BITS_39 1367 bool "39-bit" 1368 depends on PAGE_SIZE_4KB 1369 1370config ARM64_VA_BITS_42 1371 bool "42-bit" 1372 depends on PAGE_SIZE_64KB 1373 1374config ARM64_VA_BITS_47 1375 bool "47-bit" 1376 depends on PAGE_SIZE_16KB 1377 1378config ARM64_VA_BITS_48 1379 bool "48-bit" 1380 1381config ARM64_VA_BITS_52 1382 bool "52-bit" 1383 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN 1384 help 1385 Enable 52-bit virtual addressing for userspace when explicitly 1386 requested via a hint to mmap(). The kernel will also use 52-bit 1387 virtual addresses for its own mappings (provided HW support for 1388 this feature is available, otherwise it reverts to 48-bit). 1389 1390 NOTE: Enabling 52-bit virtual addressing in conjunction with 1391 ARMv8.3 Pointer Authentication will result in the PAC being 1392 reduced from 7 bits to 3 bits, which may have a significant 1393 impact on its susceptibility to brute-force attacks. 1394 1395 If unsure, select 48-bit virtual addressing instead. 1396 1397endchoice 1398 1399config ARM64_FORCE_52BIT 1400 bool "Force 52-bit virtual addresses for userspace" 1401 depends on ARM64_VA_BITS_52 && EXPERT 1402 help 1403 For systems with 52-bit userspace VAs enabled, the kernel will attempt 1404 to maintain compatibility with older software by providing 48-bit VAs 1405 unless a hint is supplied to mmap. 1406 1407 This configuration option disables the 48-bit compatibility logic, and 1408 forces all userspace addresses to be 52-bit on HW that supports it. One 1409 should only enable this configuration option for stress testing userspace 1410 memory management code. If unsure say N here. 1411 1412config ARM64_VA_BITS 1413 int 1414 default 36 if ARM64_VA_BITS_36 1415 default 39 if ARM64_VA_BITS_39 1416 default 42 if ARM64_VA_BITS_42 1417 default 47 if ARM64_VA_BITS_47 1418 default 48 if ARM64_VA_BITS_48 1419 default 52 if ARM64_VA_BITS_52 1420 1421choice 1422 prompt "Physical address space size" 1423 default ARM64_PA_BITS_48 1424 help 1425 Choose the maximum physical address range that the kernel will 1426 support. 1427 1428config ARM64_PA_BITS_48 1429 bool "48-bit" 1430 depends on ARM64_64K_PAGES || !ARM64_VA_BITS_52 1431 1432config ARM64_PA_BITS_52 1433 bool "52-bit" 1434 depends on ARM64_64K_PAGES || ARM64_VA_BITS_52 1435 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN 1436 help 1437 Enable support for a 52-bit physical address space, introduced as 1438 part of the ARMv8.2-LPA extension. 1439 1440 With this enabled, the kernel will also continue to work on CPUs that 1441 do not support ARMv8.2-LPA, but with some added memory overhead (and 1442 minor performance overhead). 1443 1444endchoice 1445 1446config ARM64_PA_BITS 1447 int 1448 default 48 if ARM64_PA_BITS_48 1449 default 52 if ARM64_PA_BITS_52 1450 1451config ARM64_LPA2 1452 def_bool y 1453 depends on ARM64_PA_BITS_52 && !ARM64_64K_PAGES 1454 1455choice 1456 prompt "Endianness" 1457 default CPU_LITTLE_ENDIAN 1458 help 1459 Select the endianness of data accesses performed by the CPU. Userspace 1460 applications will need to be compiled and linked for the endianness 1461 that is selected here. 1462 1463config CPU_BIG_ENDIAN 1464 bool "Build big-endian kernel" 1465 # https://github.com/llvm/llvm-project/commit/1379b150991f70a5782e9a143c2ba5308da1161c 1466 depends on AS_IS_GNU || AS_VERSION >= 150000 1467 help 1468 Say Y if you plan on running a kernel with a big-endian userspace. 1469 1470config CPU_LITTLE_ENDIAN 1471 bool "Build little-endian kernel" 1472 help 1473 Say Y if you plan on running a kernel with a little-endian userspace. 1474 This is usually the case for distributions targeting arm64. 1475 1476endchoice 1477 1478config SCHED_MC 1479 bool "Multi-core scheduler support" 1480 help 1481 Multi-core scheduler support improves the CPU scheduler's decision 1482 making when dealing with multi-core CPU chips at a cost of slightly 1483 increased overhead in some places. If unsure say N here. 1484 1485config SCHED_CLUSTER 1486 bool "Cluster scheduler support" 1487 help 1488 Cluster scheduler support improves the CPU scheduler's decision 1489 making when dealing with machines that have clusters of CPUs. 1490 Cluster usually means a couple of CPUs which are placed closely 1491 by sharing mid-level caches, last-level cache tags or internal 1492 busses. 1493 1494config SCHED_SMT 1495 bool "SMT scheduler support" 1496 help 1497 Improves the CPU scheduler's decision making when dealing with 1498 MultiThreading at a cost of slightly increased overhead in some 1499 places. If unsure say N here. 1500 1501config NR_CPUS 1502 int "Maximum number of CPUs (2-4096)" 1503 range 2 4096 1504 default "512" 1505 1506config HOTPLUG_CPU 1507 bool "Support for hot-pluggable CPUs" 1508 select GENERIC_IRQ_MIGRATION 1509 help 1510 Say Y here to experiment with turning CPUs off and on. CPUs 1511 can be controlled through /sys/devices/system/cpu. 1512 1513# Common NUMA Features 1514config NUMA 1515 bool "NUMA Memory Allocation and Scheduler Support" 1516 select GENERIC_ARCH_NUMA 1517 select OF_NUMA 1518 select HAVE_SETUP_PER_CPU_AREA 1519 select NEED_PER_CPU_EMBED_FIRST_CHUNK 1520 select NEED_PER_CPU_PAGE_FIRST_CHUNK 1521 select USE_PERCPU_NUMA_NODE_ID 1522 help 1523 Enable NUMA (Non-Uniform Memory Access) support. 1524 1525 The kernel will try to allocate memory used by a CPU on the 1526 local memory of the CPU and add some more 1527 NUMA awareness to the kernel. 1528 1529config NODES_SHIFT 1530 int "Maximum NUMA Nodes (as a power of 2)" 1531 range 1 10 1532 default "4" 1533 depends on NUMA 1534 help 1535 Specify the maximum number of NUMA Nodes available on the target 1536 system. Increases memory reserved to accommodate various tables. 1537 1538source "kernel/Kconfig.hz" 1539 1540config ARCH_SPARSEMEM_ENABLE 1541 def_bool y 1542 select SPARSEMEM_VMEMMAP_ENABLE 1543 select SPARSEMEM_VMEMMAP 1544 1545config HW_PERF_EVENTS 1546 def_bool y 1547 depends on ARM_PMU 1548 1549# Supported by clang >= 7.0 or GCC >= 12.0.0 1550config CC_HAVE_SHADOW_CALL_STACK 1551 def_bool $(cc-option, -fsanitize=shadow-call-stack -ffixed-x18) 1552 1553config PARAVIRT 1554 bool "Enable paravirtualization code" 1555 help 1556 This changes the kernel so it can modify itself when it is run 1557 under a hypervisor, potentially improving performance significantly 1558 over full virtualization. 1559 1560config PARAVIRT_TIME_ACCOUNTING 1561 bool "Paravirtual steal time accounting" 1562 select PARAVIRT 1563 help 1564 Select this option to enable fine granularity task steal time 1565 accounting. Time spent executing other tasks in parallel with 1566 the current vCPU is discounted from the vCPU power. To account for 1567 that, there can be a small performance impact. 1568 1569 If in doubt, say N here. 1570 1571config ARCH_SUPPORTS_KEXEC 1572 def_bool PM_SLEEP_SMP 1573 1574config ARCH_SUPPORTS_KEXEC_FILE 1575 def_bool y 1576 1577config ARCH_SELECTS_KEXEC_FILE 1578 def_bool y 1579 depends on KEXEC_FILE 1580 select HAVE_IMA_KEXEC if IMA 1581 1582config ARCH_SUPPORTS_KEXEC_SIG 1583 def_bool y 1584 1585config ARCH_SUPPORTS_KEXEC_IMAGE_VERIFY_SIG 1586 def_bool y 1587 1588config ARCH_DEFAULT_KEXEC_IMAGE_VERIFY_SIG 1589 def_bool y 1590 1591config ARCH_SUPPORTS_CRASH_DUMP 1592 def_bool y 1593 1594config ARCH_DEFAULT_CRASH_DUMP 1595 def_bool y 1596 1597config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION 1598 def_bool CRASH_RESERVE 1599 1600config TRANS_TABLE 1601 def_bool y 1602 depends on HIBERNATION || KEXEC_CORE 1603 1604config XEN_DOM0 1605 def_bool y 1606 depends on XEN 1607 1608config XEN 1609 bool "Xen guest support on ARM64" 1610 depends on ARM64 && OF 1611 select SWIOTLB_XEN 1612 select PARAVIRT 1613 help 1614 Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64. 1615 1616# include/linux/mmzone.h requires the following to be true: 1617# 1618# MAX_PAGE_ORDER + PAGE_SHIFT <= SECTION_SIZE_BITS 1619# 1620# so the maximum value of MAX_PAGE_ORDER is SECTION_SIZE_BITS - PAGE_SHIFT: 1621# 1622# | SECTION_SIZE_BITS | PAGE_SHIFT | max MAX_PAGE_ORDER | default MAX_PAGE_ORDER | 1623# ----+-------------------+--------------+----------------------+-------------------------+ 1624# 4K | 27 | 12 | 15 | 10 | 1625# 16K | 27 | 14 | 13 | 11 | 1626# 64K | 29 | 16 | 13 | 13 | 1627config ARCH_FORCE_MAX_ORDER 1628 int 1629 default "13" if ARM64_64K_PAGES 1630 default "11" if ARM64_16K_PAGES 1631 default "10" 1632 help 1633 The kernel page allocator limits the size of maximal physically 1634 contiguous allocations. The limit is called MAX_PAGE_ORDER and it 1635 defines the maximal power of two of number of pages that can be 1636 allocated as a single contiguous block. This option allows 1637 overriding the default setting when ability to allocate very 1638 large blocks of physically contiguous memory is required. 1639 1640 The maximal size of allocation cannot exceed the size of the 1641 section, so the value of MAX_PAGE_ORDER should satisfy 1642 1643 MAX_PAGE_ORDER + PAGE_SHIFT <= SECTION_SIZE_BITS 1644 1645 Don't change if unsure. 1646 1647config UNMAP_KERNEL_AT_EL0 1648 bool "Unmap kernel when running in userspace (KPTI)" if EXPERT 1649 default y 1650 help 1651 Speculation attacks against some high-performance processors can 1652 be used to bypass MMU permission checks and leak kernel data to 1653 userspace. This can be defended against by unmapping the kernel 1654 when running in userspace, mapping it back in on exception entry 1655 via a trampoline page in the vector table. 1656 1657 If unsure, say Y. 1658 1659config MITIGATE_SPECTRE_BRANCH_HISTORY 1660 bool "Mitigate Spectre style attacks against branch history" if EXPERT 1661 default y 1662 help 1663 Speculation attacks against some high-performance processors can 1664 make use of branch history to influence future speculation. 1665 When taking an exception from user-space, a sequence of branches 1666 or a firmware call overwrites the branch history. 1667 1668config RODATA_FULL_DEFAULT_ENABLED 1669 bool "Apply r/o permissions of VM areas also to their linear aliases" 1670 default y 1671 help 1672 Apply read-only attributes of VM areas to the linear alias of 1673 the backing pages as well. This prevents code or read-only data 1674 from being modified (inadvertently or intentionally) via another 1675 mapping of the same memory page. This additional enhancement can 1676 be turned off at runtime by passing rodata=[off|on] (and turned on 1677 with rodata=full if this option is set to 'n') 1678 1679 This requires the linear region to be mapped down to pages, 1680 which may adversely affect performance in some cases. 1681 1682config ARM64_SW_TTBR0_PAN 1683 bool "Emulate Privileged Access Never using TTBR0_EL1 switching" 1684 depends on !KCSAN 1685 help 1686 Enabling this option prevents the kernel from accessing 1687 user-space memory directly by pointing TTBR0_EL1 to a reserved 1688 zeroed area and reserved ASID. The user access routines 1689 restore the valid TTBR0_EL1 temporarily. 1690 1691config ARM64_TAGGED_ADDR_ABI 1692 bool "Enable the tagged user addresses syscall ABI" 1693 default y 1694 help 1695 When this option is enabled, user applications can opt in to a 1696 relaxed ABI via prctl() allowing tagged addresses to be passed 1697 to system calls as pointer arguments. For details, see 1698 Documentation/arch/arm64/tagged-address-abi.rst. 1699 1700menuconfig COMPAT 1701 bool "Kernel support for 32-bit EL0" 1702 depends on ARM64_4K_PAGES || EXPERT 1703 select HAVE_UID16 1704 select OLD_SIGSUSPEND3 1705 select COMPAT_OLD_SIGACTION 1706 help 1707 This option enables support for a 32-bit EL0 running under a 64-bit 1708 kernel at EL1. AArch32-specific components such as system calls, 1709 the user helper functions, VFP support and the ptrace interface are 1710 handled appropriately by the kernel. 1711 1712 If you use a page size other than 4KB (i.e, 16KB or 64KB), please be aware 1713 that you will only be able to execute AArch32 binaries that were compiled 1714 with page size aligned segments. 1715 1716 If you want to execute 32-bit userspace applications, say Y. 1717 1718if COMPAT 1719 1720config KUSER_HELPERS 1721 bool "Enable kuser helpers page for 32-bit applications" 1722 default y 1723 help 1724 Warning: disabling this option may break 32-bit user programs. 1725 1726 Provide kuser helpers to compat tasks. The kernel provides 1727 helper code to userspace in read only form at a fixed location 1728 to allow userspace to be independent of the CPU type fitted to 1729 the system. This permits binaries to be run on ARMv4 through 1730 to ARMv8 without modification. 1731 1732 See Documentation/arch/arm/kernel_user_helpers.rst for details. 1733 1734 However, the fixed address nature of these helpers can be used 1735 by ROP (return orientated programming) authors when creating 1736 exploits. 1737 1738 If all of the binaries and libraries which run on your platform 1739 are built specifically for your platform, and make no use of 1740 these helpers, then you can turn this option off to hinder 1741 such exploits. However, in that case, if a binary or library 1742 relying on those helpers is run, it will not function correctly. 1743 1744 Say N here only if you are absolutely certain that you do not 1745 need these helpers; otherwise, the safe option is to say Y. 1746 1747config COMPAT_VDSO 1748 bool "Enable vDSO for 32-bit applications" 1749 depends on !CPU_BIG_ENDIAN 1750 depends on (CC_IS_CLANG && LD_IS_LLD) || "$(CROSS_COMPILE_COMPAT)" != "" 1751 select GENERIC_COMPAT_VDSO 1752 default y 1753 help 1754 Place in the process address space of 32-bit applications an 1755 ELF shared object providing fast implementations of gettimeofday 1756 and clock_gettime. 1757 1758 You must have a 32-bit build of glibc 2.22 or later for programs 1759 to seamlessly take advantage of this. 1760 1761config THUMB2_COMPAT_VDSO 1762 bool "Compile the 32-bit vDSO for Thumb-2 mode" if EXPERT 1763 depends on COMPAT_VDSO 1764 default y 1765 help 1766 Compile the compat vDSO with '-mthumb -fomit-frame-pointer' if y, 1767 otherwise with '-marm'. 1768 1769config COMPAT_ALIGNMENT_FIXUPS 1770 bool "Fix up misaligned multi-word loads and stores in user space" 1771 1772menuconfig ARMV8_DEPRECATED 1773 bool "Emulate deprecated/obsolete ARMv8 instructions" 1774 depends on SYSCTL 1775 help 1776 Legacy software support may require certain instructions 1777 that have been deprecated or obsoleted in the architecture. 1778 1779 Enable this config to enable selective emulation of these 1780 features. 1781 1782 If unsure, say Y 1783 1784if ARMV8_DEPRECATED 1785 1786config SWP_EMULATION 1787 bool "Emulate SWP/SWPB instructions" 1788 help 1789 ARMv8 obsoletes the use of A32 SWP/SWPB instructions such that 1790 they are always undefined. Say Y here to enable software 1791 emulation of these instructions for userspace using LDXR/STXR. 1792 This feature can be controlled at runtime with the abi.swp 1793 sysctl which is disabled by default. 1794 1795 In some older versions of glibc [<=2.8] SWP is used during futex 1796 trylock() operations with the assumption that the code will not 1797 be preempted. This invalid assumption may be more likely to fail 1798 with SWP emulation enabled, leading to deadlock of the user 1799 application. 1800 1801 NOTE: when accessing uncached shared regions, LDXR/STXR rely 1802 on an external transaction monitoring block called a global 1803 monitor to maintain update atomicity. If your system does not 1804 implement a global monitor, this option can cause programs that 1805 perform SWP operations to uncached memory to deadlock. 1806 1807 If unsure, say Y 1808 1809config CP15_BARRIER_EMULATION 1810 bool "Emulate CP15 Barrier instructions" 1811 help 1812 The CP15 barrier instructions - CP15ISB, CP15DSB, and 1813 CP15DMB - are deprecated in ARMv8 (and ARMv7). It is 1814 strongly recommended to use the ISB, DSB, and DMB 1815 instructions instead. 1816 1817 Say Y here to enable software emulation of these 1818 instructions for AArch32 userspace code. When this option is 1819 enabled, CP15 barrier usage is traced which can help 1820 identify software that needs updating. This feature can be 1821 controlled at runtime with the abi.cp15_barrier sysctl. 1822 1823 If unsure, say Y 1824 1825config SETEND_EMULATION 1826 bool "Emulate SETEND instruction" 1827 help 1828 The SETEND instruction alters the data-endianness of the 1829 AArch32 EL0, and is deprecated in ARMv8. 1830 1831 Say Y here to enable software emulation of the instruction 1832 for AArch32 userspace code. This feature can be controlled 1833 at runtime with the abi.setend sysctl. 1834 1835 Note: All the cpus on the system must have mixed endian support at EL0 1836 for this feature to be enabled. If a new CPU - which doesn't support mixed 1837 endian - is hotplugged in after this feature has been enabled, there could 1838 be unexpected results in the applications. 1839 1840 If unsure, say Y 1841endif # ARMV8_DEPRECATED 1842 1843endif # COMPAT 1844 1845menu "ARMv8.1 architectural features" 1846 1847config ARM64_HW_AFDBM 1848 bool "Support for hardware updates of the Access and Dirty page flags" 1849 default y 1850 help 1851 The ARMv8.1 architecture extensions introduce support for 1852 hardware updates of the access and dirty information in page 1853 table entries. When enabled in TCR_EL1 (HA and HD bits) on 1854 capable processors, accesses to pages with PTE_AF cleared will 1855 set this bit instead of raising an access flag fault. 1856 Similarly, writes to read-only pages with the DBM bit set will 1857 clear the read-only bit (AP[2]) instead of raising a 1858 permission fault. 1859 1860 Kernels built with this configuration option enabled continue 1861 to work on pre-ARMv8.1 hardware and the performance impact is 1862 minimal. If unsure, say Y. 1863 1864config ARM64_PAN 1865 bool "Enable support for Privileged Access Never (PAN)" 1866 default y 1867 help 1868 Privileged Access Never (PAN; part of the ARMv8.1 Extensions) 1869 prevents the kernel or hypervisor from accessing user-space (EL0) 1870 memory directly. 1871 1872 Choosing this option will cause any unprotected (not using 1873 copy_to_user et al) memory access to fail with a permission fault. 1874 1875 The feature is detected at runtime, and will remain as a 'nop' 1876 instruction if the cpu does not implement the feature. 1877 1878config AS_HAS_LSE_ATOMICS 1879 def_bool $(as-instr,.arch_extension lse) 1880 1881config ARM64_LSE_ATOMICS 1882 bool 1883 default ARM64_USE_LSE_ATOMICS 1884 depends on AS_HAS_LSE_ATOMICS 1885 1886config ARM64_USE_LSE_ATOMICS 1887 bool "Atomic instructions" 1888 default y 1889 help 1890 As part of the Large System Extensions, ARMv8.1 introduces new 1891 atomic instructions that are designed specifically to scale in 1892 very large systems. 1893 1894 Say Y here to make use of these instructions for the in-kernel 1895 atomic routines. This incurs a small overhead on CPUs that do 1896 not support these instructions and requires the kernel to be 1897 built with binutils >= 2.25 in order for the new instructions 1898 to be used. 1899 1900endmenu # "ARMv8.1 architectural features" 1901 1902menu "ARMv8.2 architectural features" 1903 1904config AS_HAS_ARMV8_2 1905 def_bool $(cc-option,-Wa$(comma)-march=armv8.2-a) 1906 1907config AS_HAS_SHA3 1908 def_bool $(as-instr,.arch armv8.2-a+sha3) 1909 1910config ARM64_PMEM 1911 bool "Enable support for persistent memory" 1912 select ARCH_HAS_PMEM_API 1913 select ARCH_HAS_UACCESS_FLUSHCACHE 1914 help 1915 Say Y to enable support for the persistent memory API based on the 1916 ARMv8.2 DCPoP feature. 1917 1918 The feature is detected at runtime, and the kernel will use DC CVAC 1919 operations if DC CVAP is not supported (following the behaviour of 1920 DC CVAP itself if the system does not define a point of persistence). 1921 1922config ARM64_RAS_EXTN 1923 bool "Enable support for RAS CPU Extensions" 1924 default y 1925 help 1926 CPUs that support the Reliability, Availability and Serviceability 1927 (RAS) Extensions, part of ARMv8.2 are able to track faults and 1928 errors, classify them and report them to software. 1929 1930 On CPUs with these extensions system software can use additional 1931 barriers to determine if faults are pending and read the 1932 classification from a new set of registers. 1933 1934 Selecting this feature will allow the kernel to use these barriers 1935 and access the new registers if the system supports the extension. 1936 Platform RAS features may additionally depend on firmware support. 1937 1938config ARM64_CNP 1939 bool "Enable support for Common Not Private (CNP) translations" 1940 default y 1941 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN 1942 help 1943 Common Not Private (CNP) allows translation table entries to 1944 be shared between different PEs in the same inner shareable 1945 domain, so the hardware can use this fact to optimise the 1946 caching of such entries in the TLB. 1947 1948 Selecting this option allows the CNP feature to be detected 1949 at runtime, and does not affect PEs that do not implement 1950 this feature. 1951 1952endmenu # "ARMv8.2 architectural features" 1953 1954menu "ARMv8.3 architectural features" 1955 1956config ARM64_PTR_AUTH 1957 bool "Enable support for pointer authentication" 1958 default y 1959 help 1960 Pointer authentication (part of the ARMv8.3 Extensions) provides 1961 instructions for signing and authenticating pointers against secret 1962 keys, which can be used to mitigate Return Oriented Programming (ROP) 1963 and other attacks. 1964 1965 This option enables these instructions at EL0 (i.e. for userspace). 1966 Choosing this option will cause the kernel to initialise secret keys 1967 for each process at exec() time, with these keys being 1968 context-switched along with the process. 1969 1970 The feature is detected at runtime. If the feature is not present in 1971 hardware it will not be advertised to userspace/KVM guest nor will it 1972 be enabled. 1973 1974 If the feature is present on the boot CPU but not on a late CPU, then 1975 the late CPU will be parked. Also, if the boot CPU does not have 1976 address auth and the late CPU has then the late CPU will still boot 1977 but with the feature disabled. On such a system, this option should 1978 not be selected. 1979 1980config ARM64_PTR_AUTH_KERNEL 1981 bool "Use pointer authentication for kernel" 1982 default y 1983 depends on ARM64_PTR_AUTH 1984 depends on (CC_HAS_SIGN_RETURN_ADDRESS || CC_HAS_BRANCH_PROT_PAC_RET) && AS_HAS_ARMV8_3 1985 # Modern compilers insert a .note.gnu.property section note for PAC 1986 # which is only understood by binutils starting with version 2.33.1. 1987 depends on LD_IS_LLD || LD_VERSION >= 23301 || (CC_IS_GCC && GCC_VERSION < 90100) 1988 depends on !CC_IS_CLANG || AS_HAS_CFI_NEGATE_RA_STATE 1989 depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_ARGS) 1990 help 1991 If the compiler supports the -mbranch-protection or 1992 -msign-return-address flag (e.g. GCC 7 or later), then this option 1993 will cause the kernel itself to be compiled with return address 1994 protection. In this case, and if the target hardware is known to 1995 support pointer authentication, then CONFIG_STACKPROTECTOR can be 1996 disabled with minimal loss of protection. 1997 1998 This feature works with FUNCTION_GRAPH_TRACER option only if 1999 DYNAMIC_FTRACE_WITH_ARGS is enabled. 2000 2001config CC_HAS_BRANCH_PROT_PAC_RET 2002 # GCC 9 or later, clang 8 or later 2003 def_bool $(cc-option,-mbranch-protection=pac-ret+leaf) 2004 2005config CC_HAS_SIGN_RETURN_ADDRESS 2006 # GCC 7, 8 2007 def_bool $(cc-option,-msign-return-address=all) 2008 2009config AS_HAS_ARMV8_3 2010 def_bool $(cc-option,-Wa$(comma)-march=armv8.3-a) 2011 2012config AS_HAS_CFI_NEGATE_RA_STATE 2013 def_bool $(as-instr,.cfi_startproc\n.cfi_negate_ra_state\n.cfi_endproc\n) 2014 2015config AS_HAS_LDAPR 2016 def_bool $(as-instr,.arch_extension rcpc) 2017 2018endmenu # "ARMv8.3 architectural features" 2019 2020menu "ARMv8.4 architectural features" 2021 2022config ARM64_AMU_EXTN 2023 bool "Enable support for the Activity Monitors Unit CPU extension" 2024 default y 2025 help 2026 The activity monitors extension is an optional extension introduced 2027 by the ARMv8.4 CPU architecture. This enables support for version 1 2028 of the activity monitors architecture, AMUv1. 2029 2030 To enable the use of this extension on CPUs that implement it, say Y. 2031 2032 Note that for architectural reasons, firmware _must_ implement AMU 2033 support when running on CPUs that present the activity monitors 2034 extension. The required support is present in: 2035 * Version 1.5 and later of the ARM Trusted Firmware 2036 2037 For kernels that have this configuration enabled but boot with broken 2038 firmware, you may need to say N here until the firmware is fixed. 2039 Otherwise you may experience firmware panics or lockups when 2040 accessing the counter registers. Even if you are not observing these 2041 symptoms, the values returned by the register reads might not 2042 correctly reflect reality. Most commonly, the value read will be 0, 2043 indicating that the counter is not enabled. 2044 2045config AS_HAS_ARMV8_4 2046 def_bool $(cc-option,-Wa$(comma)-march=armv8.4-a) 2047 2048config ARM64_TLB_RANGE 2049 bool "Enable support for tlbi range feature" 2050 default y 2051 depends on AS_HAS_ARMV8_4 2052 help 2053 ARMv8.4-TLBI provides TLBI invalidation instruction that apply to a 2054 range of input addresses. 2055 2056 The feature introduces new assembly instructions, and they were 2057 support when binutils >= 2.30. 2058 2059endmenu # "ARMv8.4 architectural features" 2060 2061menu "ARMv8.5 architectural features" 2062 2063config AS_HAS_ARMV8_5 2064 def_bool $(cc-option,-Wa$(comma)-march=armv8.5-a) 2065 2066config ARM64_BTI 2067 bool "Branch Target Identification support" 2068 default y 2069 help 2070 Branch Target Identification (part of the ARMv8.5 Extensions) 2071 provides a mechanism to limit the set of locations to which computed 2072 branch instructions such as BR or BLR can jump. 2073 2074 To make use of BTI on CPUs that support it, say Y. 2075 2076 BTI is intended to provide complementary protection to other control 2077 flow integrity protection mechanisms, such as the Pointer 2078 authentication mechanism provided as part of the ARMv8.3 Extensions. 2079 For this reason, it does not make sense to enable this option without 2080 also enabling support for pointer authentication. Thus, when 2081 enabling this option you should also select ARM64_PTR_AUTH=y. 2082 2083 Userspace binaries must also be specifically compiled to make use of 2084 this mechanism. If you say N here or the hardware does not support 2085 BTI, such binaries can still run, but you get no additional 2086 enforcement of branch destinations. 2087 2088config ARM64_BTI_KERNEL 2089 bool "Use Branch Target Identification for kernel" 2090 default y 2091 depends on ARM64_BTI 2092 depends on ARM64_PTR_AUTH_KERNEL 2093 depends on CC_HAS_BRANCH_PROT_PAC_RET_BTI 2094 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94697 2095 depends on !CC_IS_GCC || GCC_VERSION >= 100100 2096 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106671 2097 depends on !CC_IS_GCC 2098 depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_ARGS) 2099 help 2100 Build the kernel with Branch Target Identification annotations 2101 and enable enforcement of this for kernel code. When this option 2102 is enabled and the system supports BTI all kernel code including 2103 modular code must have BTI enabled. 2104 2105config CC_HAS_BRANCH_PROT_PAC_RET_BTI 2106 # GCC 9 or later, clang 8 or later 2107 def_bool $(cc-option,-mbranch-protection=pac-ret+leaf+bti) 2108 2109config ARM64_E0PD 2110 bool "Enable support for E0PD" 2111 default y 2112 help 2113 E0PD (part of the ARMv8.5 extensions) allows us to ensure 2114 that EL0 accesses made via TTBR1 always fault in constant time, 2115 providing similar benefits to KASLR as those provided by KPTI, but 2116 with lower overhead and without disrupting legitimate access to 2117 kernel memory such as SPE. 2118 2119 This option enables E0PD for TTBR1 where available. 2120 2121config ARM64_AS_HAS_MTE 2122 # Initial support for MTE went in binutils 2.32.0, checked with 2123 # ".arch armv8.5-a+memtag" below. However, this was incomplete 2124 # as a late addition to the final architecture spec (LDGM/STGM) 2125 # is only supported in the newer 2.32.x and 2.33 binutils 2126 # versions, hence the extra "stgm" instruction check below. 2127 def_bool $(as-instr,.arch armv8.5-a+memtag\nstgm xzr$(comma)[x0]) 2128 2129config ARM64_MTE 2130 bool "Memory Tagging Extension support" 2131 default y 2132 depends on ARM64_AS_HAS_MTE && ARM64_TAGGED_ADDR_ABI 2133 depends on AS_HAS_ARMV8_5 2134 depends on AS_HAS_LSE_ATOMICS 2135 # Required for tag checking in the uaccess routines 2136 depends on ARM64_PAN 2137 select ARCH_HAS_SUBPAGE_FAULTS 2138 select ARCH_USES_HIGH_VMA_FLAGS 2139 select ARCH_USES_PG_ARCH_2 2140 select ARCH_USES_PG_ARCH_3 2141 help 2142 Memory Tagging (part of the ARMv8.5 Extensions) provides 2143 architectural support for run-time, always-on detection of 2144 various classes of memory error to aid with software debugging 2145 to eliminate vulnerabilities arising from memory-unsafe 2146 languages. 2147 2148 This option enables the support for the Memory Tagging 2149 Extension at EL0 (i.e. for userspace). 2150 2151 Selecting this option allows the feature to be detected at 2152 runtime. Any secondary CPU not implementing this feature will 2153 not be allowed a late bring-up. 2154 2155 Userspace binaries that want to use this feature must 2156 explicitly opt in. The mechanism for the userspace is 2157 described in: 2158 2159 Documentation/arch/arm64/memory-tagging-extension.rst. 2160 2161endmenu # "ARMv8.5 architectural features" 2162 2163menu "ARMv8.7 architectural features" 2164 2165config ARM64_EPAN 2166 bool "Enable support for Enhanced Privileged Access Never (EPAN)" 2167 default y 2168 depends on ARM64_PAN 2169 help 2170 Enhanced Privileged Access Never (EPAN) allows Privileged 2171 Access Never to be used with Execute-only mappings. 2172 2173 The feature is detected at runtime, and will remain disabled 2174 if the cpu does not implement the feature. 2175endmenu # "ARMv8.7 architectural features" 2176 2177config AS_HAS_MOPS 2178 def_bool $(as-instr,.arch_extension mops) 2179 2180menu "ARMv8.9 architectural features" 2181 2182config ARM64_POE 2183 prompt "Permission Overlay Extension" 2184 def_bool y 2185 select ARCH_USES_HIGH_VMA_FLAGS 2186 select ARCH_HAS_PKEYS 2187 help 2188 The Permission Overlay Extension is used to implement Memory 2189 Protection Keys. Memory Protection Keys provides a mechanism for 2190 enforcing page-based protections, but without requiring modification 2191 of the page tables when an application changes protection domains. 2192 2193 For details, see Documentation/core-api/protection-keys.rst 2194 2195 If unsure, say y. 2196 2197config ARCH_PKEY_BITS 2198 int 2199 default 3 2200 2201config ARM64_HAFT 2202 bool "Support for Hardware managed Access Flag for Table Descriptors" 2203 depends on ARM64_HW_AFDBM 2204 default y 2205 help 2206 The ARMv8.9/ARMv9.5 introduces the feature Hardware managed Access 2207 Flag for Table descriptors. When enabled an architectural executed 2208 memory access will update the Access Flag in each Table descriptor 2209 which is accessed during the translation table walk and for which 2210 the Access Flag is 0. The Access Flag of the Table descriptor use 2211 the same bit of PTE_AF. 2212 2213 The feature will only be enabled if all the CPUs in the system 2214 support this feature. If unsure, say Y. 2215 2216endmenu # "ARMv8.9 architectural features" 2217 2218menu "v9.4 architectural features" 2219 2220config ARM64_GCS 2221 bool "Enable support for Guarded Control Stack (GCS)" 2222 default y 2223 select ARCH_HAS_USER_SHADOW_STACK 2224 select ARCH_USES_HIGH_VMA_FLAGS 2225 depends on !UPROBES 2226 help 2227 Guarded Control Stack (GCS) provides support for a separate 2228 stack with restricted access which contains only return 2229 addresses. This can be used to harden against some attacks 2230 by comparing return address used by the program with what is 2231 stored in the GCS, and may also be used to efficiently obtain 2232 the call stack for applications such as profiling. 2233 2234 The feature is detected at runtime, and will remain disabled 2235 if the system does not implement the feature. 2236 2237endmenu # "v9.4 architectural features" 2238 2239config ARM64_SVE 2240 bool "ARM Scalable Vector Extension support" 2241 default y 2242 help 2243 The Scalable Vector Extension (SVE) is an extension to the AArch64 2244 execution state which complements and extends the SIMD functionality 2245 of the base architecture to support much larger vectors and to enable 2246 additional vectorisation opportunities. 2247 2248 To enable use of this extension on CPUs that implement it, say Y. 2249 2250 On CPUs that support the SVE2 extensions, this option will enable 2251 those too. 2252 2253 Note that for architectural reasons, firmware _must_ implement SVE 2254 support when running on SVE capable hardware. The required support 2255 is present in: 2256 2257 * version 1.5 and later of the ARM Trusted Firmware 2258 * the AArch64 boot wrapper since commit 5e1261e08abf 2259 ("bootwrapper: SVE: Enable SVE for EL2 and below"). 2260 2261 For other firmware implementations, consult the firmware documentation 2262 or vendor. 2263 2264 If you need the kernel to boot on SVE-capable hardware with broken 2265 firmware, you may need to say N here until you get your firmware 2266 fixed. Otherwise, you may experience firmware panics or lockups when 2267 booting the kernel. If unsure and you are not observing these 2268 symptoms, you should assume that it is safe to say Y. 2269 2270config ARM64_SME 2271 bool "ARM Scalable Matrix Extension support" 2272 default y 2273 depends on ARM64_SVE 2274 depends on BROKEN 2275 help 2276 The Scalable Matrix Extension (SME) is an extension to the AArch64 2277 execution state which utilises a substantial subset of the SVE 2278 instruction set, together with the addition of new architectural 2279 register state capable of holding two dimensional matrix tiles to 2280 enable various matrix operations. 2281 2282config ARM64_PSEUDO_NMI 2283 bool "Support for NMI-like interrupts" 2284 select ARM_GIC_V3 2285 help 2286 Adds support for mimicking Non-Maskable Interrupts through the use of 2287 GIC interrupt priority. This support requires version 3 or later of 2288 ARM GIC. 2289 2290 This high priority configuration for interrupts needs to be 2291 explicitly enabled by setting the kernel parameter 2292 "irqchip.gicv3_pseudo_nmi" to 1. 2293 2294 If unsure, say N 2295 2296if ARM64_PSEUDO_NMI 2297config ARM64_DEBUG_PRIORITY_MASKING 2298 bool "Debug interrupt priority masking" 2299 help 2300 This adds runtime checks to functions enabling/disabling 2301 interrupts when using priority masking. The additional checks verify 2302 the validity of ICC_PMR_EL1 when calling concerned functions. 2303 2304 If unsure, say N 2305endif # ARM64_PSEUDO_NMI 2306 2307config RELOCATABLE 2308 bool "Build a relocatable kernel image" if EXPERT 2309 select ARCH_HAS_RELR 2310 default y 2311 help 2312 This builds the kernel as a Position Independent Executable (PIE), 2313 which retains all relocation metadata required to relocate the 2314 kernel binary at runtime to a different virtual address than the 2315 address it was linked at. 2316 Since AArch64 uses the RELA relocation format, this requires a 2317 relocation pass at runtime even if the kernel is loaded at the 2318 same address it was linked at. 2319 2320config RANDOMIZE_BASE 2321 bool "Randomize the address of the kernel image" 2322 select RELOCATABLE 2323 help 2324 Randomizes the virtual address at which the kernel image is 2325 loaded, as a security feature that deters exploit attempts 2326 relying on knowledge of the location of kernel internals. 2327 2328 It is the bootloader's job to provide entropy, by passing a 2329 random u64 value in /chosen/kaslr-seed at kernel entry. 2330 2331 When booting via the UEFI stub, it will invoke the firmware's 2332 EFI_RNG_PROTOCOL implementation (if available) to supply entropy 2333 to the kernel proper. In addition, it will randomise the physical 2334 location of the kernel Image as well. 2335 2336 If unsure, say N. 2337 2338config RANDOMIZE_MODULE_REGION_FULL 2339 bool "Randomize the module region over a 2 GB range" 2340 depends on RANDOMIZE_BASE 2341 default y 2342 help 2343 Randomizes the location of the module region inside a 2 GB window 2344 covering the core kernel. This way, it is less likely for modules 2345 to leak information about the location of core kernel data structures 2346 but it does imply that function calls between modules and the core 2347 kernel will need to be resolved via veneers in the module PLT. 2348 2349 When this option is not set, the module region will be randomized over 2350 a limited range that contains the [_stext, _etext] interval of the 2351 core kernel, so branch relocations are almost always in range unless 2352 the region is exhausted. In this particular case of region 2353 exhaustion, modules might be able to fall back to a larger 2GB area. 2354 2355config CC_HAVE_STACKPROTECTOR_SYSREG 2356 def_bool $(cc-option,-mstack-protector-guard=sysreg -mstack-protector-guard-reg=sp_el0 -mstack-protector-guard-offset=0) 2357 2358config STACKPROTECTOR_PER_TASK 2359 def_bool y 2360 depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_SYSREG 2361 2362config UNWIND_PATCH_PAC_INTO_SCS 2363 bool "Enable shadow call stack dynamically using code patching" 2364 # needs Clang with https://github.com/llvm/llvm-project/commit/de07cde67b5d205d58690be012106022aea6d2b3 incorporated 2365 depends on CC_IS_CLANG && CLANG_VERSION >= 150000 2366 depends on ARM64_PTR_AUTH_KERNEL && CC_HAS_BRANCH_PROT_PAC_RET 2367 depends on SHADOW_CALL_STACK 2368 select UNWIND_TABLES 2369 select DYNAMIC_SCS 2370 2371config ARM64_CONTPTE 2372 bool "Contiguous PTE mappings for user memory" if EXPERT 2373 depends on TRANSPARENT_HUGEPAGE 2374 default y 2375 help 2376 When enabled, user mappings are configured using the PTE contiguous 2377 bit, for any mappings that meet the size and alignment requirements. 2378 This reduces TLB pressure and improves performance. 2379 2380endmenu # "Kernel Features" 2381 2382menu "Boot options" 2383 2384config ARM64_ACPI_PARKING_PROTOCOL 2385 bool "Enable support for the ARM64 ACPI parking protocol" 2386 depends on ACPI 2387 help 2388 Enable support for the ARM64 ACPI parking protocol. If disabled 2389 the kernel will not allow booting through the ARM64 ACPI parking 2390 protocol even if the corresponding data is present in the ACPI 2391 MADT table. 2392 2393config CMDLINE 2394 string "Default kernel command string" 2395 default "" 2396 help 2397 Provide a set of default command-line options at build time by 2398 entering them here. As a minimum, you should specify the the 2399 root device (e.g. root=/dev/nfs). 2400 2401choice 2402 prompt "Kernel command line type" 2403 depends on CMDLINE != "" 2404 default CMDLINE_FROM_BOOTLOADER 2405 help 2406 Choose how the kernel will handle the provided default kernel 2407 command line string. 2408 2409config CMDLINE_FROM_BOOTLOADER 2410 bool "Use bootloader kernel arguments if available" 2411 help 2412 Uses the command-line options passed by the boot loader. If 2413 the boot loader doesn't provide any, the default kernel command 2414 string provided in CMDLINE will be used. 2415 2416config CMDLINE_FORCE 2417 bool "Always use the default kernel command string" 2418 help 2419 Always use the default kernel command string, even if the boot 2420 loader passes other arguments to the kernel. 2421 This is useful if you cannot or don't want to change the 2422 command-line options your boot loader passes to the kernel. 2423 2424endchoice 2425 2426config EFI_STUB 2427 bool 2428 2429config EFI 2430 bool "UEFI runtime support" 2431 depends on OF && !CPU_BIG_ENDIAN 2432 depends on KERNEL_MODE_NEON 2433 select ARCH_SUPPORTS_ACPI 2434 select LIBFDT 2435 select UCS2_STRING 2436 select EFI_PARAMS_FROM_FDT 2437 select EFI_RUNTIME_WRAPPERS 2438 select EFI_STUB 2439 select EFI_GENERIC_STUB 2440 imply IMA_SECURE_AND_OR_TRUSTED_BOOT 2441 default y 2442 help 2443 This option provides support for runtime services provided 2444 by UEFI firmware (such as non-volatile variables, realtime 2445 clock, and platform reset). A UEFI stub is also provided to 2446 allow the kernel to be booted as an EFI application. This 2447 is only useful on systems that have UEFI firmware. 2448 2449config COMPRESSED_INSTALL 2450 bool "Install compressed image by default" 2451 help 2452 This makes the regular "make install" install the compressed 2453 image we built, not the legacy uncompressed one. 2454 2455 You can check that a compressed image works for you by doing 2456 "make zinstall" first, and verifying that everything is fine 2457 in your environment before making "make install" do this for 2458 you. 2459 2460config DMI 2461 bool "Enable support for SMBIOS (DMI) tables" 2462 depends on EFI 2463 default y 2464 help 2465 This enables SMBIOS/DMI feature for systems. 2466 2467 This option is only useful on systems that have UEFI firmware. 2468 However, even with this option, the resultant kernel should 2469 continue to boot on existing non-UEFI platforms. 2470 2471endmenu # "Boot options" 2472 2473menu "Power management options" 2474 2475source "kernel/power/Kconfig" 2476 2477config ARCH_HIBERNATION_POSSIBLE 2478 def_bool y 2479 depends on CPU_PM 2480 2481config ARCH_HIBERNATION_HEADER 2482 def_bool y 2483 depends on HIBERNATION 2484 2485config ARCH_SUSPEND_POSSIBLE 2486 def_bool y 2487 2488endmenu # "Power management options" 2489 2490menu "CPU Power Management" 2491 2492source "drivers/cpuidle/Kconfig" 2493 2494source "drivers/cpufreq/Kconfig" 2495 2496endmenu # "CPU Power Management" 2497 2498source "drivers/acpi/Kconfig" 2499 2500source "arch/arm64/kvm/Kconfig" 2501 2502