1# SPDX-License-Identifier: GPL-2.0 2# Select 32 or 64 bit 3config 64BIT 4 bool "64-bit kernel" if "$(ARCH)" = "x86" 5 default "$(ARCH)" != "i386" 6 help 7 Say yes to build a 64-bit kernel - formerly known as x86_64 8 Say no to build a 32-bit kernel - formerly known as i386 9 10config X86_32 11 def_bool y 12 depends on !64BIT 13 # Options that are inherently 32-bit kernel only: 14 select ARCH_WANT_IPC_PARSE_VERSION 15 select CLKSRC_I8253 16 select CLONE_BACKWARDS 17 select HAVE_DEBUG_STACKOVERFLOW 18 select KMAP_LOCAL 19 select MODULES_USE_ELF_REL 20 select OLD_SIGACTION 21 select ARCH_SPLIT_ARG64 22 23config X86_64 24 def_bool y 25 depends on 64BIT 26 # Options that are inherently 64-bit kernel only: 27 select ARCH_HAS_GIGANTIC_PAGE 28 select ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS 29 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 30 select ARCH_SUPPORTS_PER_VMA_LOCK 31 select ARCH_SUPPORTS_HUGE_PFNMAP if TRANSPARENT_HUGEPAGE 32 select HAVE_ARCH_SOFT_DIRTY 33 select MODULES_USE_ELF_RELA 34 select NEED_DMA_MAP_STATE 35 select SWIOTLB 36 select ARCH_HAS_ELFCORE_COMPAT 37 select ZONE_DMA32 38 select EXECMEM if DYNAMIC_FTRACE 39 select ACPI_MRRM if ACPI 40 41config FORCE_DYNAMIC_FTRACE 42 def_bool y 43 depends on X86_32 44 depends on FUNCTION_TRACER 45 select DYNAMIC_FTRACE 46 help 47 We keep the static function tracing (!DYNAMIC_FTRACE) around 48 in order to test the non static function tracing in the 49 generic code, as other architectures still use it. But we 50 only need to keep it around for x86_64. No need to keep it 51 for x86_32. For x86_32, force DYNAMIC_FTRACE. 52# 53# Arch settings 54# 55# ( Note that options that are marked 'if X86_64' could in principle be 56# ported to 32-bit as well. ) 57# 58config X86 59 def_bool y 60 # 61 # Note: keep this list sorted alphabetically 62 # 63 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 64 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 65 select ACPI_HOTPLUG_CPU if ACPI_PROCESSOR && HOTPLUG_CPU 66 select ARCH_32BIT_OFF_T if X86_32 67 select ARCH_CLOCKSOURCE_INIT 68 select ARCH_CONFIGURES_CPU_MITIGATIONS 69 select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 70 select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION 71 select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64 72 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE) 73 select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE 74 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 75 select ARCH_HAS_CPU_ATTACK_VECTORS if CPU_MITIGATIONS 76 select ARCH_HAS_CACHE_LINE_SIZE 77 select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION 78 select ARCH_HAS_CPU_FINALIZE_INIT 79 select ARCH_HAS_CPU_PASID if IOMMU_SVA 80 select ARCH_HAS_CURRENT_STACK_POINTER 81 select ARCH_HAS_DEBUG_VIRTUAL 82 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 83 select ARCH_HAS_DEVMEM_IS_ALLOWED 84 select ARCH_HAS_DMA_OPS if GART_IOMMU || XEN 85 select ARCH_HAS_EARLY_DEBUG if KGDB 86 select ARCH_HAS_ELF_RANDOMIZE 87 select ARCH_HAS_EXECMEM_ROX if X86_64 && STRICT_MODULE_RWX 88 select ARCH_HAS_FAST_MULTIPLIER 89 select ARCH_HAS_FORTIFY_SOURCE 90 select ARCH_HAS_GCOV_PROFILE_ALL 91 select ARCH_HAS_KCOV if X86_64 92 select ARCH_HAS_KERNEL_FPU_SUPPORT 93 select ARCH_HAS_MEM_ENCRYPT 94 select ARCH_HAS_MEMBARRIER_SYNC_CORE 95 select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS 96 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 97 select ARCH_HAS_PMEM_API if X86_64 98 select ARCH_HAS_PREEMPT_LAZY 99 select ARCH_HAS_PTDUMP 100 select ARCH_HAS_PTE_SPECIAL 101 select ARCH_HAS_HW_PTE_YOUNG 102 select ARCH_HAS_NONLEAF_PMD_YOUNG if PGTABLE_LEVELS > 2 103 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 104 select ARCH_HAS_COPY_MC if X86_64 105 select ARCH_HAS_SET_MEMORY 106 select ARCH_HAS_SET_DIRECT_MAP 107 select ARCH_HAS_STRICT_KERNEL_RWX 108 select ARCH_HAS_STRICT_MODULE_RWX 109 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 110 select ARCH_HAS_SYSCALL_WRAPPER 111 select ARCH_HAS_UBSAN 112 select ARCH_HAS_DEBUG_WX 113 select ARCH_HAS_ZONE_DMA_SET if EXPERT 114 select ARCH_HAVE_NMI_SAFE_CMPXCHG 115 select ARCH_HAVE_EXTRA_ELF_NOTES 116 select ARCH_MEMORY_ORDER_TSO 117 select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 118 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 119 select ARCH_MIGHT_HAVE_PC_PARPORT 120 select ARCH_MIGHT_HAVE_PC_SERIO 121 select ARCH_STACKWALK 122 select ARCH_SUPPORTS_ACPI 123 select ARCH_SUPPORTS_ATOMIC_RMW 124 select ARCH_SUPPORTS_DEBUG_PAGEALLOC 125 select ARCH_SUPPORTS_HUGETLBFS 126 select ARCH_SUPPORTS_PAGE_TABLE_CHECK if X86_64 127 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 128 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 129 select ARCH_SUPPORTS_CFI if X86_64 130 select ARCH_USES_CFI_TRAPS if X86_64 && CFI 131 select ARCH_SUPPORTS_LTO_CLANG 132 select ARCH_SUPPORTS_LTO_CLANG_THIN 133 select ARCH_SUPPORTS_RT 134 select ARCH_USE_BUILTIN_BSWAP 135 select ARCH_USE_CMPXCHG_LOCKREF 136 select ARCH_USE_MEMTEST 137 select ARCH_USE_QUEUED_RWLOCKS 138 select ARCH_USE_QUEUED_SPINLOCKS 139 select ARCH_USE_SYM_ANNOTATIONS 140 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 141 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 142 select ARCH_WANTS_CLOCKSOURCE_READ_INLINE if X86_64 143 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 144 select ARCH_WANTS_NO_INSTR 145 select ARCH_WANT_GENERAL_HUGETLB 146 select ARCH_WANT_HUGE_PMD_SHARE if X86_64 147 select ARCH_WANT_LD_ORPHAN_WARN 148 select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP if X86_64 149 select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP if X86_64 150 select ARCH_WANT_HUGETLB_VMEMMAP_PREINIT if X86_64 151 select ARCH_WANTS_THP_SWAP if X86_64 152 select ARCH_HAS_PARANOID_L1D_FLUSH 153 select ARCH_WANT_IRQS_OFF_ACTIVATE_MM 154 select BUILDTIME_TABLE_SORT 155 select CLKEVT_I8253 156 select CLOCKSOURCE_WATCHDOG 157 # Word-size accesses may read uninitialized data past the trailing \0 158 # in strings and cause false KMSAN reports. 159 select DCACHE_WORD_ACCESS if !KMSAN 160 select DYNAMIC_SIGFRAME 161 select EDAC_ATOMIC_SCRUB 162 select EDAC_SUPPORT 163 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 164 select GENERIC_CLOCKEVENTS_BROADCAST_IDLE if GENERIC_CLOCKEVENTS_BROADCAST 165 select GENERIC_CLOCKEVENTS_COUPLED_INLINE if X86_64 166 select GENERIC_CLOCKEVENTS_MIN_ADJUST 167 select GENERIC_CMOS_UPDATE 168 select GENERIC_CPU_AUTOPROBE 169 select GENERIC_CPU_DEVICES 170 select GENERIC_CPU_VULNERABILITIES 171 select GENERIC_EARLY_IOREMAP 172 select GENERIC_ENTRY 173 select GENERIC_IOMAP 174 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 175 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 176 select GENERIC_IRQ_MIGRATION if SMP 177 select GENERIC_IRQ_PROBE 178 select GENERIC_IRQ_RESERVATION_MODE 179 select GENERIC_IRQ_SHOW 180 select GENERIC_PENDING_IRQ if SMP 181 select GENERIC_SMP_IDLE_THREAD 182 select GENERIC_GETTIMEOFDAY 183 select GENERIC_VDSO_OVERFLOW_PROTECT 184 select GUP_GET_PXX_LOW_HIGH if X86_PAE 185 select HARDIRQS_SW_RESEND 186 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 187 select HAS_IOPORT 188 select HAVE_ACPI_APEI if ACPI 189 select HAVE_ACPI_APEI_NMI if ACPI 190 select HAVE_ALIGNED_STRUCT_PAGE 191 select HAVE_ARCH_AUDITSYSCALL 192 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 193 select HAVE_ARCH_HUGE_VMALLOC if X86_64 194 select HAVE_ARCH_JUMP_LABEL 195 select HAVE_ARCH_JUMP_LABEL_RELATIVE 196 select HAVE_ARCH_KASAN if X86_64 197 select HAVE_ARCH_KASAN_VMALLOC if X86_64 198 select HAVE_ARCH_KFENCE 199 select HAVE_ARCH_KMSAN if X86_64 200 select HAVE_ARCH_KGDB 201 select HAVE_ARCH_KSTACK_ERASE 202 select HAVE_ARCH_MMAP_RND_BITS if MMU 203 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 204 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 205 select HAVE_ARCH_PREL32_RELOCATIONS 206 select HAVE_ARCH_SECCOMP_FILTER 207 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 208 select HAVE_ARCH_TRACEHOOK 209 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 210 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 211 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 212 select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 213 select HAVE_ARCH_VMAP_STACK if X86_64 214 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 215 select HAVE_ARCH_WITHIN_STACK_FRAMES 216 select HAVE_ASM_MODVERSIONS 217 select HAVE_CMPXCHG_DOUBLE 218 select HAVE_CMPXCHG_LOCAL 219 select HAVE_CONTEXT_TRACKING_USER if X86_64 220 select HAVE_CONTEXT_TRACKING_USER_OFFSTACK if HAVE_CONTEXT_TRACKING_USER 221 select HAVE_C_RECORDMCOUNT 222 select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL 223 select HAVE_OBJTOOL_NOP_MCOUNT if HAVE_OBJTOOL_MCOUNT 224 select HAVE_BUILDTIME_MCOUNT_SORT 225 select HAVE_DEBUG_KMEMLEAK 226 select HAVE_DMA_CONTIGUOUS 227 select HAVE_DYNAMIC_FTRACE 228 select HAVE_DYNAMIC_FTRACE_WITH_REGS 229 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 230 select HAVE_FTRACE_REGS_HAVING_PT_REGS if X86_64 231 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 232 select HAVE_DYNAMIC_FTRACE_WITH_JMP if X86_64 233 select HAVE_SAMPLE_FTRACE_DIRECT if X86_64 234 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64 235 select HAVE_EBPF_JIT 236 select HAVE_EFFICIENT_UNALIGNED_ACCESS 237 select HAVE_EISA if X86_32 238 select HAVE_EXIT_THREAD 239 select HAVE_FUTEX_ROBUST_UNLOCK 240 select HAVE_GENERIC_TIF_BITS 241 select HAVE_GUP_FAST 242 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 243 select HAVE_FTRACE_GRAPH_FUNC if HAVE_FUNCTION_GRAPH_TRACER 244 select HAVE_FUNCTION_GRAPH_FREGS if HAVE_FUNCTION_GRAPH_TRACER 245 select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) 246 select HAVE_FUNCTION_TRACER 247 select HAVE_GCC_PLUGINS 248 select HAVE_HW_BREAKPOINT 249 select HAVE_IOREMAP_PROT 250 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 251 select HAVE_IRQ_TIME_ACCOUNTING 252 select HAVE_JUMP_LABEL_HACK if HAVE_OBJTOOL 253 select HAVE_KERNEL_BZIP2 254 select HAVE_KERNEL_GZIP 255 select HAVE_KERNEL_LZ4 256 select HAVE_KERNEL_LZMA 257 select HAVE_KERNEL_LZO 258 select HAVE_KERNEL_XZ 259 select HAVE_KERNEL_ZSTD 260 select HAVE_KPROBES 261 select HAVE_KPROBES_ON_FTRACE 262 select HAVE_FUNCTION_ERROR_INJECTION 263 select HAVE_KRETPROBES 264 select HAVE_RETHOOK 265 select HAVE_KLP_BUILD if X86_64 266 select HAVE_LIVEPATCH if X86_64 267 select HAVE_MIXED_BREAKPOINTS_REGS 268 select HAVE_MOD_ARCH_SPECIFIC 269 select HAVE_MOVE_PMD 270 select HAVE_MOVE_PUD 271 select HAVE_NOINSTR_HACK if HAVE_OBJTOOL 272 select HAVE_NMI 273 select HAVE_NOINSTR_VALIDATION if HAVE_OBJTOOL 274 select HAVE_OBJTOOL if X86_64 275 select HAVE_OPTPROBES 276 select HAVE_PAGE_SIZE_4KB 277 select HAVE_PCSPKR_PLATFORM 278 select HAVE_PERF_EVENTS 279 select HAVE_PERF_EVENTS_NMI 280 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 281 select HAVE_PCI 282 select HAVE_PERF_REGS 283 select HAVE_PERF_USER_STACK_DUMP 284 select ASYNC_KERNEL_PGTABLE_FREE if IOMMU_SVA 285 select MMU_GATHER_RCU_TABLE_FREE 286 select MMU_GATHER_MERGE_VMAS 287 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 288 select HAVE_REGS_AND_STACK_ACCESS_API 289 select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC || STACK_VALIDATION 290 select HAVE_FUNCTION_ARG_ACCESS_API 291 select HAVE_SETUP_PER_CPU_AREA 292 select HAVE_SOFTIRQ_ON_OWN_STACK 293 select HAVE_STACKPROTECTOR 294 select HAVE_STACK_VALIDATION if HAVE_OBJTOOL 295 select HAVE_STATIC_CALL 296 select HAVE_STATIC_CALL_INLINE if HAVE_OBJTOOL 297 select HAVE_PREEMPT_DYNAMIC_CALL 298 select HAVE_RSEQ 299 select HAVE_RUST if X86_64 300 select HAVE_SYSCALL_TRACEPOINTS 301 select HAVE_UACCESS_VALIDATION if HAVE_OBJTOOL 302 select HAVE_UNSTABLE_SCHED_CLOCK 303 select HAVE_UNWIND_USER_FP if X86_64 304 select HAVE_USER_RETURN_NOTIFIER 305 select HAVE_GENERIC_VDSO 306 select VDSO_GETRANDOM if X86_64 307 select HOTPLUG_PARALLEL if SMP && X86_64 308 select HOTPLUG_SMT if SMP 309 select HOTPLUG_SPLIT_STARTUP if SMP && X86_32 310 select IRQ_FORCED_THREADING 311 select LOCK_MM_AND_FIND_VMA 312 select NEED_PER_CPU_EMBED_FIRST_CHUNK 313 select NEED_PER_CPU_PAGE_FIRST_CHUNK 314 select NEED_SG_DMA_LENGTH 315 select NUMA_MEMBLKS if NUMA 316 select PCI_DOMAINS if PCI 317 select PCI_LOCKLESS_CONFIG if PCI 318 select PERF_EVENTS 319 select RTC_LIB 320 select RTC_MC146818_LIB 321 select SPARSE_IRQ 322 select SYSCTL_EXCEPTION_TRACE 323 select THREAD_INFO_IN_TASK 324 select TRACE_IRQFLAGS_SUPPORT 325 select TRACE_IRQFLAGS_NMI_SUPPORT 326 select USER_STACKTRACE_SUPPORT 327 select HAVE_ARCH_KCSAN if X86_64 328 select PROC_PID_ARCH_STATUS if PROC_FS 329 select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX 330 select FUNCTION_ALIGNMENT_16B if X86_64 || X86_ALIGNMENT_16 331 select FUNCTION_ALIGNMENT_4B 332 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 333 select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 334 select ARCH_SUPPORTS_SCHED_SMT if SMP 335 select SCHED_SMT if SMP 336 select ARCH_SUPPORTS_SCHED_CLUSTER if SMP 337 select ARCH_SUPPORTS_SCHED_MC if SMP 338 select HAVE_SINGLE_FTRACE_DIRECT_OPS if X86_64 && DYNAMIC_FTRACE_WITH_DIRECT_CALLS 339 340config INSTRUCTION_DECODER 341 def_bool y 342 depends on KPROBES || PERF_EVENTS || UPROBES 343 344config OUTPUT_FORMAT 345 string 346 default "elf32-i386" if X86_32 347 default "elf64-x86-64" if X86_64 348 349config LOCKDEP_SUPPORT 350 def_bool y 351 352config STACKTRACE_SUPPORT 353 def_bool y 354 355config MMU 356 def_bool y 357 358config ARCH_MMAP_RND_BITS_MIN 359 default 28 if 64BIT 360 default 8 361 362config ARCH_MMAP_RND_BITS_MAX 363 default 32 if 64BIT 364 default 16 365 366config ARCH_MMAP_RND_COMPAT_BITS_MIN 367 default 8 368 369config ARCH_MMAP_RND_COMPAT_BITS_MAX 370 default 16 371 372config SBUS 373 bool 374 375config GENERIC_ISA_DMA 376 def_bool y 377 depends on ISA_DMA_API 378 379config GENERIC_CSUM 380 bool 381 default y if KMSAN || KASAN 382 383config GENERIC_BUG 384 def_bool y 385 depends on BUG 386 select GENERIC_BUG_RELATIVE_POINTERS 387 388config GENERIC_BUG_RELATIVE_POINTERS 389 bool 390 391config ARCH_MAY_HAVE_PC_FDC 392 def_bool y 393 depends on ISA_DMA_API 394 395config GENERIC_CALIBRATE_DELAY 396 def_bool y 397 398config ARCH_HAS_CPU_RELAX 399 def_bool y 400 401config ARCH_HIBERNATION_POSSIBLE 402 def_bool y 403 404config ARCH_SUSPEND_POSSIBLE 405 def_bool y 406 407config AUDIT_ARCH 408 def_bool y if X86_64 409 410config KASAN_SHADOW_OFFSET 411 hex 412 depends on KASAN 413 default 0xdffffc0000000000 414 415config HAVE_INTEL_TXT 416 def_bool y 417 depends on INTEL_IOMMU && ACPI 418 419config ARCH_SUPPORTS_UPROBES 420 def_bool y 421 422config FIX_EARLYCON_MEM 423 def_bool y 424 425config DYNAMIC_PHYSICAL_MASK 426 bool 427 428config PGTABLE_LEVELS 429 int 430 default 5 if X86_64 431 default 3 if X86_PAE 432 default 2 433 434menu "Processor type and features" 435 436config SMP 437 bool "Symmetric multi-processing support" 438 help 439 This enables support for systems with more than one CPU. If you have 440 a system with only one CPU, say N. If you have a system with more 441 than one CPU, say Y. 442 443 If you say N here, the kernel will run on uni- and multiprocessor 444 machines, but will use only one CPU of a multiprocessor machine. If 445 you say Y here, the kernel will run on many, but not all, 446 uniprocessor machines. On a uniprocessor machine, the kernel 447 will run faster if you say N here. 448 449 People using multiprocessor machines who say Y here should also say 450 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 451 Management" code will be disabled if you say Y here. 452 453 See also <file:Documentation/arch/x86/i386/IO-APIC.rst>, 454 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 455 <http://www.tldp.org/docs.html#howto>. 456 457 If you don't know what to do here, say N. 458 459config X86_X2APIC 460 bool "x2APIC interrupt controller architecture support" 461 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 462 default y 463 help 464 x2APIC is an interrupt controller architecture, a component of which 465 (the local APIC) is present in the CPU. It allows faster access to 466 the local APIC and supports a larger number of CPUs in the system 467 than the predecessors. 468 469 x2APIC was introduced in Intel CPUs around 2008 and in AMD EPYC CPUs 470 in 2019, but it can be disabled by the BIOS. It is also frequently 471 emulated in virtual machines, even when the host CPU does not support 472 it. Support in the CPU can be checked by executing 473 grep x2apic /proc/cpuinfo 474 475 If this configuration option is disabled, the kernel will boot with 476 very reduced functionality and performance on some platforms that 477 have x2APIC enabled. On the other hand, on hardware that does not 478 support x2APIC, a kernel with this option enabled will just fallback 479 to older APIC implementations. 480 481 If in doubt, say Y. 482 483config AMD_SECURE_AVIC 484 bool "AMD Secure AVIC" 485 depends on AMD_MEM_ENCRYPT && X86_X2APIC 486 help 487 Enable this to get AMD Secure AVIC support on guests that have this feature. 488 489 AMD Secure AVIC provides hardware acceleration for performance sensitive 490 APIC accesses and support for managing guest owned APIC state for SEV-SNP 491 guests. Secure AVIC does not support xAPIC mode. It has functional 492 dependency on x2apic being enabled in the guest. 493 494 If you don't know what to do here, say N. 495 496config X86_POSTED_MSI 497 bool "Enable MSI and MSI-x delivery by posted interrupts" 498 depends on X86_64 && IRQ_REMAP 499 help 500 This enables MSIs that are under interrupt remapping to be delivered as 501 posted interrupts to the host kernel. Interrupt throughput can 502 potentially be improved by coalescing CPU notifications during high 503 frequency bursts. 504 505 If you don't know what to do here, say N. 506 507config X86_MPPARSE 508 bool "Enable MPS table" if ACPI 509 default y 510 depends on X86_LOCAL_APIC 511 help 512 For old smp systems that do not have proper acpi support. Newer systems 513 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 514 515config X86_CPU_RESCTRL 516 bool "x86 CPU resource control support" 517 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 518 depends on MISC_FILESYSTEMS 519 select ARCH_HAS_CPU_RESCTRL 520 select RESCTRL_FS 521 select RESCTRL_FS_PSEUDO_LOCK 522 help 523 Enable x86 CPU resource control support. 524 525 Provide support for the allocation and monitoring of system resources 526 usage by the CPU. 527 528 Intel calls this Intel Resource Director Technology 529 (Intel(R) RDT). More information about RDT can be found in the 530 Intel x86 Architecture Software Developer Manual. 531 532 AMD calls this AMD Platform Quality of Service (AMD QoS). 533 More information about AMD QoS can be found in the AMD64 Technology 534 Platform Quality of Service Extensions manual. 535 536 Say N if unsure. 537 538config X86_CPU_RESCTRL_INTEL_AET 539 bool "Intel Application Energy Telemetry" 540 depends on X86_64 && X86_CPU_RESCTRL && CPU_SUP_INTEL && INTEL_PMT_TELEMETRY=y && INTEL_TPMI=y 541 help 542 Enable per-RMID telemetry events in resctrl. 543 544 Intel feature that collects per-RMID execution data 545 about energy consumption, measure of frequency independent 546 activity and other performance metrics. Data is aggregated 547 per package. 548 549 Say N if unsure. 550 551config X86_FRED 552 bool "Flexible Return and Event Delivery" 553 depends on X86_64 554 help 555 When enabled, use Flexible Return and Event Delivery 556 instead of the legacy SYSCALL/SYSENTER/IDT architecture for 557 ring transitions and exception/interrupt handling if the 558 system supports it. 559 560config X86_EXTENDED_PLATFORM 561 bool "Support for extended (non-PC) x86 platforms" 562 default y 563 help 564 If you disable this option then the kernel will only support 565 standard PC platforms. (which covers the vast majority of 566 systems out there.) 567 568 If you enable this option then you'll be able to select support 569 for the following non-PC x86 platforms, depending on the value of 570 CONFIG_64BIT. 571 572 32-bit platforms (CONFIG_64BIT=n): 573 Goldfish (mostly Android emulator) 574 Intel CE media processor (CE4100) SoC 575 Intel Quark 576 RDC R-321x SoC 577 578 64-bit platforms (CONFIG_64BIT=y): 579 Numascale NumaChip 580 ScaleMP vSMP 581 SGI Ultraviolet 582 Merrifield/Moorefield MID devices 583 Goldfish (mostly Android emulator) 584 585 If you have one of these systems, or if you want to build a 586 generic distribution kernel, say Y here - otherwise say N. 587 588# This is an alphabetically sorted list of 64 bit extended platforms 589# Please maintain the alphabetic order if and when there are additions 590config X86_NUMACHIP 591 bool "Numascale NumaChip" 592 depends on X86_64 593 depends on X86_EXTENDED_PLATFORM 594 depends on NUMA 595 depends on SMP 596 depends on X86_X2APIC 597 depends on PCI_MMCONFIG 598 help 599 Adds support for Numascale NumaChip large-SMP systems. Needed to 600 enable more than ~168 cores. 601 If you don't have one of these, you should say N here. 602 603config X86_VSMP 604 bool "ScaleMP vSMP" 605 select HYPERVISOR_GUEST 606 select PARAVIRT 607 depends on X86_64 && PCI 608 depends on X86_EXTENDED_PLATFORM 609 depends on SMP 610 help 611 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 612 supposed to run on these EM64T-based machines. Only choose this option 613 if you have one of these machines. 614 615config X86_UV 616 bool "SGI Ultraviolet" 617 depends on X86_64 618 depends on X86_EXTENDED_PLATFORM 619 depends on NUMA 620 depends on EFI 621 depends on KEXEC_CORE 622 depends on X86_X2APIC 623 depends on PCI 624 help 625 This option is needed in order to support SGI Ultraviolet systems. 626 If you don't have one of these, you should say N here. 627 628config X86_INTEL_MID 629 bool "Intel Z34xx/Z35xx MID platform support" 630 depends on X86_EXTENDED_PLATFORM 631 depends on X86_PLATFORM_DEVICES 632 depends on PCI 633 depends on X86_64 || (EXPERT && PCI_GOANY) 634 depends on X86_IO_APIC 635 select I2C 636 select DW_APB_TIMER 637 select INTEL_SCU_PCI 638 help 639 Select to build a kernel capable of supporting 64-bit Intel MID 640 (Mobile Internet Device) platform systems which do not have 641 the PCI legacy interfaces. 642 643 The only supported devices are the 22nm Merrified (Z34xx) 644 and Moorefield (Z35xx) SoC used in the Intel Edison board and 645 a small number of Android devices such as the Asus Zenfone 2, 646 Asus FonePad 8 and Dell Venue 7. 647 648 If you are building for a PC class system or non-MID tablet 649 SoCs like Bay Trail (Z36xx/Z37xx), say N here. 650 651 Intel MID platforms are based on an Intel processor and chipset which 652 consume less power than most of the x86 derivatives. 653 654config X86_GOLDFISH 655 bool "Goldfish (Virtual Platform)" 656 depends on X86_EXTENDED_PLATFORM 657 help 658 Enable support for the Goldfish virtual platform used primarily 659 for Android development. Unless you are building for the Android 660 Goldfish emulator say N here. 661 662# Following is an alphabetically sorted list of 32 bit extended platforms 663# Please maintain the alphabetic order if and when there are additions 664 665config X86_INTEL_CE 666 bool "CE4100 TV platform" 667 depends on PCI 668 depends on PCI_GODIRECT 669 depends on X86_IO_APIC 670 depends on X86_32 671 depends on X86_EXTENDED_PLATFORM 672 select X86_REBOOTFIXUPS 673 select OF 674 select OF_EARLY_FLATTREE 675 help 676 Select for the Intel CE media processor (CE4100) SOC. 677 This option compiles in support for the CE4100 SOC for settop 678 boxes and media devices. 679 680config X86_INTEL_QUARK 681 bool "Intel Quark platform support" 682 depends on X86_32 683 depends on X86_EXTENDED_PLATFORM 684 depends on X86_PLATFORM_DEVICES 685 depends on PCI 686 depends on PCI_GOANY 687 depends on X86_IO_APIC 688 select IOSF_MBI 689 select INTEL_IMR 690 select COMMON_CLK 691 help 692 Select to include support for Quark X1000 SoC. 693 Say Y here if you have a Quark based system such as the Arduino 694 compatible Intel Galileo. 695 696config X86_INTEL_LPSS 697 bool "Intel Low Power Subsystem Support" 698 depends on X86 && ACPI && PCI 699 select COMMON_CLK 700 select PINCTRL 701 select IOSF_MBI 702 help 703 Select to build support for Intel Low Power Subsystem such as 704 found on Intel Lynxpoint PCH. Selecting this option enables 705 things like clock tree (common clock framework) and pincontrol 706 which are needed by the LPSS peripheral drivers. 707 708config X86_AMD_PLATFORM_DEVICE 709 bool "AMD ACPI2Platform devices support" 710 depends on ACPI 711 select COMMON_CLK 712 select PINCTRL 713 help 714 Select to interpret AMD specific ACPI device to platform device 715 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 716 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 717 implemented under PINCTRL subsystem. 718 719config IOSF_MBI 720 tristate "Intel SoC IOSF Sideband support for SoC platforms" 721 depends on PCI 722 help 723 This option enables sideband register access support for Intel SoC 724 platforms. On these platforms the IOSF sideband is used in lieu of 725 MSR's for some register accesses, mostly but not limited to thermal 726 and power. Drivers may query the availability of this device to 727 determine if they need the sideband in order to work on these 728 platforms. The sideband is available on the following SoC products. 729 This list is not meant to be exclusive. 730 - BayTrail 731 - Braswell 732 - Quark 733 734 You should say Y if you are running a kernel on one of these SoC's. 735 736config IOSF_MBI_DEBUG 737 bool "Enable IOSF sideband access through debugfs" 738 depends on IOSF_MBI && DEBUG_FS 739 help 740 Select this option to expose the IOSF sideband access registers (MCR, 741 MDR, MCRX) through debugfs to write and read register information from 742 different units on the SoC. This is most useful for obtaining device 743 state information for debug and analysis. As this is a general access 744 mechanism, users of this option would have specific knowledge of the 745 device they want to access. 746 747 If you don't require the option or are in doubt, say N. 748 749config X86_SUPPORTS_MEMORY_FAILURE 750 def_bool y 751 # MCE code calls memory_failure(): 752 depends on X86_MCE 753 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 754 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 755 depends on X86_64 || !SPARSEMEM 756 select ARCH_SUPPORTS_MEMORY_FAILURE 757 758config X86_32_IRIS 759 tristate "Eurobraille/Iris poweroff module" 760 depends on X86_32 761 help 762 The Iris machines from EuroBraille do not have APM or ACPI support 763 to shut themselves down properly. A special I/O sequence is 764 needed to do so, which is what this module does at 765 kernel shutdown. 766 767 This is only for Iris machines from EuroBraille. 768 769 If unused, say N. 770 771config SCHED_OMIT_FRAME_POINTER 772 def_bool y 773 prompt "Single-depth WCHAN output" 774 depends on X86 775 help 776 Calculate simpler /proc/<PID>/wchan values. If this option 777 is disabled then wchan values will recurse back to the 778 caller function. This provides more accurate wchan values, 779 at the expense of slightly more scheduling overhead. 780 781 If in doubt, say "Y". 782 783menuconfig HYPERVISOR_GUEST 784 bool "Linux guest support" 785 help 786 Say Y here to enable options for running Linux under various hyper- 787 visors. This option enables basic hypervisor detection and platform 788 setup. 789 790 If you say N, all options in this submenu will be skipped and 791 disabled, and Linux guest support won't be built in. 792 793if HYPERVISOR_GUEST 794 795config PARAVIRT 796 bool "Enable paravirtualization code" 797 depends on HAVE_STATIC_CALL 798 select HAVE_PV_STEAL_CLOCK_GEN 799 help 800 This changes the kernel so it can modify itself when it is run 801 under a hypervisor, potentially improving performance significantly 802 over full virtualization. However, when run without a hypervisor 803 the kernel is theoretically slower and slightly larger. 804 805config PARAVIRT_XXL 806 bool 807 depends on X86_64 808 select ARCH_HAS_LAZY_MMU_MODE 809 810config PARAVIRT_SPINLOCKS 811 bool "Paravirtualization layer for spinlocks" 812 depends on PARAVIRT && SMP 813 help 814 Paravirtualized spinlocks allow a pvops backend to replace the 815 spinlock implementation with something virtualization-friendly 816 (for example, block the virtual CPU rather than spinning). 817 818 It has a minimal impact on native kernels and gives a nice performance 819 benefit on paravirtualized KVM / Xen kernels. 820 821 If you are unsure how to answer this question, answer Y. 822 823config X86_HV_CALLBACK_VECTOR 824 def_bool n 825 826source "arch/x86/xen/Kconfig" 827 828config KVM_GUEST 829 bool "KVM Guest support (including kvmclock)" 830 depends on PARAVIRT 831 select PARAVIRT_CLOCK 832 select ARCH_CPUIDLE_HALTPOLL 833 select X86_HV_CALLBACK_VECTOR 834 default y 835 help 836 This option enables various optimizations for running under the KVM 837 hypervisor. It includes a paravirtualized clock, so that instead 838 of relying on a PIT (or probably other) emulation by the 839 underlying device model, the host provides the guest with 840 timing infrastructure such as time of day, and system time 841 842config ARCH_CPUIDLE_HALTPOLL 843 def_bool n 844 prompt "Disable host haltpoll when loading haltpoll driver" 845 help 846 If virtualized under KVM, disable host haltpoll. 847 848config PVH 849 bool "Support for running PVH guests" 850 help 851 This option enables the PVH entry point for guest virtual machines 852 as specified in the x86/HVM direct boot ABI. 853 854config PARAVIRT_TIME_ACCOUNTING 855 bool "Paravirtual steal time accounting" 856 depends on PARAVIRT 857 help 858 Select this option to enable fine granularity task steal time 859 accounting. Time spent executing other tasks in parallel with 860 the current vCPU is discounted from the vCPU power. To account for 861 that, there can be a small performance impact. 862 863 If in doubt, say N here. 864 865config PARAVIRT_CLOCK 866 bool 867 868config JAILHOUSE_GUEST 869 bool "Jailhouse non-root cell support" 870 depends on X86_64 && PCI 871 select X86_PM_TIMER 872 help 873 This option allows to run Linux as guest in a Jailhouse non-root 874 cell. You can leave this option disabled if you only want to start 875 Jailhouse and run Linux afterwards in the root cell. 876 877config ACRN_GUEST 878 bool "ACRN Guest support" 879 depends on X86_64 880 select X86_HV_CALLBACK_VECTOR 881 help 882 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 883 a flexible, lightweight reference open-source hypervisor, built with 884 real-time and safety-criticality in mind. It is built for embedded 885 IOT with small footprint and real-time features. More details can be 886 found in https://projectacrn.org/. 887 888config BHYVE_GUEST 889 bool "Bhyve (BSD Hypervisor) Guest support" 890 depends on X86_64 891 help 892 This option allows to run Linux to recognise when it is running as a 893 guest in the Bhyve hypervisor, and to support more than 255 vCPUs when 894 when doing so. More details about Bhyve can be found at https://bhyve.org 895 and https://wiki.freebsd.org/bhyve/. 896 897config INTEL_TDX_GUEST 898 bool "Intel TDX (Trust Domain Extensions) - Guest Support" 899 depends on X86_64 && CPU_SUP_INTEL 900 depends on X86_X2APIC 901 depends on EFI_STUB 902 depends on PARAVIRT 903 select ARCH_HAS_CC_PLATFORM 904 select X86_MEM_ENCRYPT 905 select X86_MCE 906 select UNACCEPTED_MEMORY 907 help 908 Support running as a guest under Intel TDX. Without this support, 909 the guest kernel can not boot or run under TDX. 910 TDX includes memory encryption and integrity capabilities 911 which protect the confidentiality and integrity of guest 912 memory contents and CPU state. TDX guests are protected from 913 some attacks from the VMM. 914 915endif # HYPERVISOR_GUEST 916 917source "arch/x86/Kconfig.cpu" 918 919config HPET_TIMER 920 def_bool X86_64 921 prompt "HPET Timer Support" if X86_32 922 help 923 Use the IA-PC HPET (High Precision Event Timer) to manage 924 time in preference to the PIT and RTC, if a HPET is 925 present. 926 HPET is the next generation timer replacing legacy 8254s. 927 The HPET provides a stable time base on SMP 928 systems, unlike the TSC, but it is more expensive to access, 929 as it is off-chip. The interface used is documented 930 in the HPET spec, revision 1. 931 932 You can safely choose Y here. However, HPET will only be 933 activated if the platform and the BIOS support this feature. 934 Otherwise the 8254 will be used for timing services. 935 936 Choose N to continue using the legacy 8254 timer. 937 938config HPET_EMULATE_RTC 939 def_bool y 940 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 941 942# Mark as expert because too many people got it wrong. 943# The code disables itself when not needed. 944config DMI 945 default y 946 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 947 bool "Enable DMI scanning" if EXPERT 948 help 949 Enabled scanning of DMI to identify machine quirks. Say Y 950 here unless you have verified that your setup is not 951 affected by entries in the DMI blacklist. Required by PNP 952 BIOS code. 953 954config GART_IOMMU 955 bool "Old AMD GART IOMMU support" 956 select IOMMU_HELPER 957 select SWIOTLB 958 depends on X86_64 && PCI && AMD_NB 959 help 960 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 961 GART based hardware IOMMUs. 962 963 The GART supports full DMA access for devices with 32-bit access 964 limitations, on systems with more than 3 GB. This is usually needed 965 for USB, sound, many IDE/SATA chipsets and some other devices. 966 967 Newer systems typically have a modern AMD IOMMU, supported via 968 the CONFIG_AMD_IOMMU=y config option. 969 970 In normal configurations this driver is only active when needed: 971 there's more than 3 GB of memory and the system contains a 972 32-bit limited device. 973 974 If unsure, say Y. 975 976config BOOT_VESA_SUPPORT 977 bool 978 help 979 If true, at least one selected framebuffer driver can take advantage 980 of VESA video modes set at an early boot stage via the vga= parameter. 981 982config MAXSMP 983 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 984 depends on X86_64 && SMP && DEBUG_KERNEL 985 select CPUMASK_OFFSTACK 986 help 987 Enable maximum number of CPUS and NUMA Nodes for this architecture. 988 If unsure, say N. 989 990# 991# The maximum number of CPUs supported: 992# 993# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 994# and which can be configured interactively in the 995# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 996# 997# The ranges are different on 32-bit and 64-bit kernels, depending on 998# hardware capabilities and scalability features of the kernel. 999# 1000# ( If MAXSMP is enabled we just use the highest possible value and disable 1001# interactive configuration. ) 1002# 1003 1004config NR_CPUS_RANGE_BEGIN 1005 int 1006 default NR_CPUS_RANGE_END if MAXSMP 1007 default 1 if !SMP 1008 default 2 1009 1010config NR_CPUS_RANGE_END 1011 int 1012 depends on X86_32 1013 default 8 if SMP 1014 default 1 if !SMP 1015 1016config NR_CPUS_RANGE_END 1017 int 1018 depends on X86_64 1019 default 8192 if SMP && CPUMASK_OFFSTACK 1020 default 512 if SMP && !CPUMASK_OFFSTACK 1021 default 1 if !SMP 1022 1023config NR_CPUS_DEFAULT 1024 int 1025 depends on X86_32 1026 default 8 if SMP 1027 default 1 if !SMP 1028 1029config NR_CPUS_DEFAULT 1030 int 1031 depends on X86_64 1032 default 8192 if MAXSMP 1033 default 64 if SMP 1034 default 1 if !SMP 1035 1036config NR_CPUS 1037 int "Maximum number of CPUs" if SMP && !MAXSMP 1038 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1039 default NR_CPUS_DEFAULT 1040 help 1041 This allows you to specify the maximum number of CPUs which this 1042 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1043 supported value is 8192, otherwise the maximum value is 512. The 1044 minimum value which makes sense is 2. 1045 1046 This is purely to save memory: each supported CPU adds about 8KB 1047 to the kernel image. 1048 1049config SCHED_MC_PRIO 1050 bool "CPU core priorities scheduler support" 1051 depends on SCHED_MC 1052 select X86_INTEL_PSTATE if CPU_SUP_INTEL 1053 select X86_AMD_PSTATE if CPU_SUP_AMD && ACPI 1054 select CPU_FREQ 1055 default y 1056 help 1057 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1058 core ordering determined at manufacturing time, which allows 1059 certain cores to reach higher turbo frequencies (when running 1060 single threaded workloads) than others. 1061 1062 Enabling this kernel feature teaches the scheduler about 1063 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1064 scheduler's CPU selection logic accordingly, so that higher 1065 overall system performance can be achieved. 1066 1067 This feature will have no effect on CPUs without this feature. 1068 1069 If unsure say Y here. 1070 1071config UP_LATE_INIT 1072 def_bool y 1073 depends on !SMP && X86_LOCAL_APIC 1074 1075config X86_UP_APIC 1076 bool "Local APIC support on uniprocessors" if !PCI_MSI 1077 default PCI_MSI 1078 depends on X86_32 && !SMP 1079 help 1080 A local APIC (Advanced Programmable Interrupt Controller) is an 1081 integrated interrupt controller in the CPU. If you have a single-CPU 1082 system which has a processor with a local APIC, you can say Y here to 1083 enable and use it. If you say Y here even though your machine doesn't 1084 have a local APIC, then the kernel will still run with no slowdown at 1085 all. The local APIC supports CPU-generated self-interrupts (timer, 1086 performance counters), and the NMI watchdog which detects hard 1087 lockups. 1088 1089config X86_UP_IOAPIC 1090 bool "IO-APIC support on uniprocessors" 1091 depends on X86_UP_APIC 1092 help 1093 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1094 SMP-capable replacement for PC-style interrupt controllers. Most 1095 SMP systems and many recent uniprocessor systems have one. 1096 1097 If you have a single-CPU system with an IO-APIC, you can say Y here 1098 to use it. If you say Y here even though your machine doesn't have 1099 an IO-APIC, then the kernel will still run with no slowdown at all. 1100 1101config X86_LOCAL_APIC 1102 def_bool y 1103 depends on X86_64 || SMP || X86_UP_APIC || PCI_MSI 1104 select IRQ_DOMAIN_HIERARCHY 1105 1106config ACPI_MADT_WAKEUP 1107 def_bool y 1108 depends on X86_64 1109 depends on ACPI 1110 depends on SMP 1111 depends on X86_LOCAL_APIC 1112 1113config X86_IO_APIC 1114 def_bool y 1115 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1116 1117config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1118 bool "Reroute for broken boot IRQs" 1119 depends on X86_IO_APIC 1120 help 1121 This option enables a workaround that fixes a source of 1122 spurious interrupts. This is recommended when threaded 1123 interrupt handling is used on systems where the generation of 1124 superfluous "boot interrupts" cannot be disabled. 1125 1126 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1127 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1128 kernel does during interrupt handling). On chipsets where this 1129 boot IRQ generation cannot be disabled, this workaround keeps 1130 the original IRQ line masked so that only the equivalent "boot 1131 IRQ" is delivered to the CPUs. The workaround also tells the 1132 kernel to set up the IRQ handler on the boot IRQ line. In this 1133 way only one interrupt is delivered to the kernel. Otherwise 1134 the spurious second interrupt may cause the kernel to bring 1135 down (vital) interrupt lines. 1136 1137 Only affects "broken" chipsets. Interrupt sharing may be 1138 increased on these systems. 1139 1140config X86_MCE 1141 bool "Machine Check / overheating reporting" 1142 select GENERIC_ALLOCATOR 1143 default y 1144 help 1145 Machine Check support allows the processor to notify the 1146 kernel if it detects a problem (e.g. overheating, data corruption). 1147 The action the kernel takes depends on the severity of the problem, 1148 ranging from warning messages to halting the machine. 1149 1150config X86_MCELOG_LEGACY 1151 bool "Support for deprecated /dev/mcelog character device" 1152 depends on X86_MCE 1153 help 1154 Enable support for /dev/mcelog which is needed by the old mcelog 1155 userspace logging daemon. Consider switching to the new generation 1156 rasdaemon solution. 1157 1158config X86_MCE_INTEL 1159 def_bool y 1160 prompt "Intel MCE features" 1161 depends on X86_MCE && X86_LOCAL_APIC 1162 help 1163 Additional support for intel specific MCE features such as 1164 the thermal monitor. 1165 1166config X86_MCE_AMD 1167 def_bool y 1168 prompt "AMD MCE features" 1169 depends on X86_MCE && X86_LOCAL_APIC 1170 help 1171 Additional support for AMD specific MCE features such as 1172 the DRAM Error Threshold. 1173 1174config X86_ANCIENT_MCE 1175 bool "Support for old Pentium 5 / WinChip machine checks" 1176 depends on X86_32 && X86_MCE 1177 help 1178 Include support for machine check handling on old Pentium 5 or WinChip 1179 systems. These typically need to be enabled explicitly on the command 1180 line. 1181 1182config X86_MCE_THRESHOLD 1183 depends on X86_MCE_AMD || X86_MCE_INTEL 1184 def_bool y 1185 1186config X86_MCE_INJECT 1187 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1188 tristate "Machine check injector support" 1189 help 1190 Provide support for injecting machine checks for testing purposes. 1191 If you don't know what a machine check is and you don't do kernel 1192 QA it is safe to say n. 1193 1194source "arch/x86/events/Kconfig" 1195 1196config X86_LEGACY_VM86 1197 bool "Legacy VM86 support" 1198 depends on X86_32 1199 help 1200 This option allows user programs to put the CPU into V8086 1201 mode, which is an 80286-era approximation of 16-bit real mode. 1202 1203 Some very old versions of X and/or vbetool require this option 1204 for user mode setting. Similarly, DOSEMU will use it if 1205 available to accelerate real mode DOS programs. However, any 1206 recent version of DOSEMU, X, or vbetool should be fully 1207 functional even without kernel VM86 support, as they will all 1208 fall back to software emulation. Nevertheless, if you are using 1209 a 16-bit DOS program where 16-bit performance matters, vm86 1210 mode might be faster than emulation and you might want to 1211 enable this option. 1212 1213 Note that any app that works on a 64-bit kernel is unlikely to 1214 need this option, as 64-bit kernels don't, and can't, support 1215 V8086 mode. This option is also unrelated to 16-bit protected 1216 mode and is not needed to run most 16-bit programs under Wine. 1217 1218 Enabling this option increases the complexity of the kernel 1219 and slows down exception handling a tiny bit. 1220 1221 If unsure, say N here. 1222 1223config VM86 1224 bool 1225 default X86_LEGACY_VM86 1226 1227config X86_16BIT 1228 bool "Enable support for 16-bit segments" if EXPERT 1229 default y 1230 depends on MODIFY_LDT_SYSCALL 1231 help 1232 This option is required by programs like Wine to run 16-bit 1233 protected mode legacy code on x86 processors. Disabling 1234 this option saves about 300 bytes on i386, or around 6K text 1235 plus 16K runtime memory on x86-64, 1236 1237config X86_ESPFIX32 1238 def_bool y 1239 depends on X86_16BIT && X86_32 1240 1241config X86_ESPFIX64 1242 def_bool y 1243 depends on X86_16BIT && X86_64 1244 1245config X86_VSYSCALL_EMULATION 1246 bool "Enable vsyscall emulation" if EXPERT 1247 default y 1248 depends on X86_64 1249 help 1250 This enables emulation of the legacy vsyscall page. Disabling 1251 it is roughly equivalent to booting with vsyscall=none, except 1252 that it will also disable the helpful warning if a program 1253 tries to use a vsyscall. With this option set to N, offending 1254 programs will just segfault, citing addresses of the form 1255 0xffffffffff600?00. 1256 1257 This option is required by many programs built before 2013, and 1258 care should be used even with newer programs if set to N. 1259 1260 Disabling this option saves about 7K of kernel size and 1261 possibly 4K of additional runtime pagetable memory. 1262 1263config X86_IOPL_IOPERM 1264 bool "IOPERM and IOPL Emulation" 1265 default y 1266 help 1267 This enables the ioperm() and iopl() syscalls which are necessary 1268 for legacy applications. 1269 1270 Legacy IOPL support is an overbroad mechanism which allows user 1271 space aside of accessing all 65536 I/O ports also to disable 1272 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1273 capabilities and permission from potentially active security 1274 modules. 1275 1276 The emulation restricts the functionality of the syscall to 1277 only allowing the full range I/O port access, but prevents the 1278 ability to disable interrupts from user space which would be 1279 granted if the hardware IOPL mechanism would be used. 1280 1281config TOSHIBA 1282 tristate "Toshiba Laptop support" 1283 depends on X86_32 1284 help 1285 This adds a driver to safely access the System Management Mode of 1286 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1287 not work on models with a Phoenix BIOS. The System Management Mode 1288 is used to set the BIOS and power saving options on Toshiba portables. 1289 1290 For information on utilities to make use of this driver see the 1291 Toshiba Linux utilities web site at: 1292 <http://www.buzzard.org.uk/toshiba/>. 1293 1294 Say Y if you intend to run this kernel on a Toshiba portable. 1295 Say N otherwise. 1296 1297config X86_REBOOTFIXUPS 1298 bool "Enable X86 board specific fixups for reboot" 1299 depends on X86_32 1300 help 1301 This enables chipset and/or board specific fixups to be done 1302 in order to get reboot to work correctly. This is only needed on 1303 some combinations of hardware and BIOS. The symptom, for which 1304 this config is intended, is when reboot ends with a stalled/hung 1305 system. 1306 1307 Currently, the only fixup is for the Geode machines using 1308 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1309 1310 Say Y if you want to enable the fixup. Currently, it's safe to 1311 enable this option even if you don't need it. 1312 Say N otherwise. 1313 1314config MICROCODE 1315 def_bool y 1316 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1317 select CRYPTO_LIB_SHA256 if CPU_SUP_AMD 1318 1319config MICROCODE_INITRD32 1320 def_bool y 1321 depends on MICROCODE && X86_32 && BLK_DEV_INITRD 1322 1323config MICROCODE_LATE_LOADING 1324 bool "Late microcode loading (DANGEROUS)" 1325 default n 1326 depends on MICROCODE && SMP 1327 help 1328 Loading microcode late, when the system is up and executing instructions 1329 is a tricky business and should be avoided if possible. Just the sequence 1330 of synchronizing all cores and SMT threads is one fragile dance which does 1331 not guarantee that cores might not softlock after the loading. Therefore, 1332 use this at your own risk. Late loading taints the kernel unless the 1333 microcode header indicates that it is safe for late loading via the 1334 minimal revision check. This minimal revision check can be enforced on 1335 the kernel command line with "microcode=force_minrev". 1336 1337config MICROCODE_LATE_FORCE_MINREV 1338 bool "Enforce late microcode loading minimal revision check" 1339 default n 1340 depends on MICROCODE_LATE_LOADING 1341 help 1342 To prevent that users load microcode late which modifies already 1343 in use features, newer microcode patches have a minimum revision field 1344 in the microcode header, which tells the kernel which minimum 1345 revision must be active in the CPU to safely load that new microcode 1346 late into the running system. If disabled the check will not 1347 be enforced but the kernel will be tainted when the minimal 1348 revision check fails. 1349 1350 This minimal revision check can also be controlled via the 1351 "microcode=force_minrev" parameter on the kernel command line. 1352 1353 If unsure say Y. 1354 1355config MICROCODE_DBG 1356 bool "Enable microcode loader debugging" 1357 default n 1358 depends on MICROCODE 1359 help 1360 Enable code which allows to debug the microcode loader. When running 1361 in a guest the patch loading is simulated but everything else 1362 related to patch parsing and handling is done as on baremetal with 1363 the purpose of debugging solely the software side of things. On 1364 baremetal, it simply dumps additional debugging information during 1365 normal operation. 1366 1367 You almost certainly want to say n here. 1368 1369config X86_MSR 1370 tristate "/dev/cpu/*/msr - Model-specific register support" 1371 help 1372 This device gives privileged processes access to the x86 1373 Model-Specific Registers (MSRs). It is a character device with 1374 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1375 MSR accesses are directed to a specific CPU on multi-processor 1376 systems. 1377 1378config X86_CPUID 1379 tristate "/dev/cpu/*/cpuid - CPU information support" 1380 help 1381 This device gives processes access to the x86 CPUID instruction to 1382 be executed on a specific processor. It is a character device 1383 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1384 /dev/cpu/31/cpuid. 1385 1386config HIGHMEM4G 1387 bool "High Memory Support" 1388 depends on X86_32 1389 help 1390 Linux can use up to 4 Gigabytes of physical memory on x86 systems. 1391 However, the address space of 32-bit x86 processors is only 4 1392 Gigabytes large. That means that, if you have a large amount of 1393 physical memory, not all of it can be "permanently mapped" by the 1394 kernel. The physical memory that's not permanently mapped is called 1395 "high memory". 1396 1397 If you are compiling a kernel which will never run on a machine with 1398 more than 1 Gigabyte total physical RAM, answer "off" here (default 1399 choice and suitable for most users). This will result in a "3GB/1GB" 1400 split: 3GB are mapped so that each process sees a 3GB virtual memory 1401 space and the remaining part of the 4GB virtual memory space is used 1402 by the kernel to permanently map as much physical memory as 1403 possible. 1404 1405 If the machine has between 1 and 4 Gigabytes physical RAM, then 1406 answer "Y" here. 1407 1408 If unsure, say N. 1409 1410choice 1411 prompt "Memory split" if EXPERT 1412 default VMSPLIT_3G 1413 depends on X86_32 1414 help 1415 Select the desired split between kernel and user memory. 1416 1417 If the address range available to the kernel is less than the 1418 physical memory installed, the remaining memory will be available 1419 as "high memory". Accessing high memory is a little more costly 1420 than low memory, as it needs to be mapped into the kernel first. 1421 Note that increasing the kernel address space limits the range 1422 available to user programs, making the address space there 1423 tighter. Selecting anything other than the default 3G/1G split 1424 will also likely make your kernel incompatible with binary-only 1425 kernel modules. 1426 1427 If you are not absolutely sure what you are doing, leave this 1428 option alone! 1429 1430 config VMSPLIT_3G 1431 bool "3G/1G user/kernel split" 1432 config VMSPLIT_3G_OPT 1433 depends on !X86_PAE 1434 bool "3G/1G user/kernel split (for full 1G low memory)" 1435 config VMSPLIT_2G 1436 bool "2G/2G user/kernel split" 1437 config VMSPLIT_2G_OPT 1438 depends on !X86_PAE 1439 bool "2G/2G user/kernel split (for full 2G low memory)" 1440 config VMSPLIT_1G 1441 bool "1G/3G user/kernel split" 1442endchoice 1443 1444config PAGE_OFFSET 1445 hex 1446 default 0xB0000000 if VMSPLIT_3G_OPT 1447 default 0x80000000 if VMSPLIT_2G 1448 default 0x78000000 if VMSPLIT_2G_OPT 1449 default 0x40000000 if VMSPLIT_1G 1450 default 0xC0000000 1451 depends on X86_32 1452 1453config HIGHMEM 1454 def_bool HIGHMEM4G 1455 1456config X86_PAE 1457 bool "PAE (Physical Address Extension) Support" 1458 depends on X86_32 && X86_HAVE_PAE 1459 select PHYS_ADDR_T_64BIT 1460 help 1461 PAE is required for NX support, and furthermore enables 1462 larger swapspace support for non-overcommit purposes. It 1463 has the cost of more pagetable lookup overhead, and also 1464 consumes more pagetable space per process. 1465 1466config X86_DIRECT_GBPAGES 1467 def_bool y 1468 depends on X86_64 1469 help 1470 Certain kernel features effectively disable kernel 1471 linear 1 GB mappings (even if the CPU otherwise 1472 supports them), so don't confuse the user by printing 1473 that we have them enabled. 1474 1475config X86_CPA_STATISTICS 1476 bool "Enable statistic for Change Page Attribute" 1477 depends on DEBUG_FS 1478 help 1479 Expose statistics about the Change Page Attribute mechanism, which 1480 helps to determine the effectiveness of preserving large and huge 1481 page mappings when mapping protections are changed. 1482 1483config X86_MEM_ENCRYPT 1484 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1485 select DYNAMIC_PHYSICAL_MASK 1486 def_bool n 1487 1488config AMD_MEM_ENCRYPT 1489 bool "AMD Secure Memory Encryption (SME) support" 1490 depends on X86_64 && CPU_SUP_AMD 1491 depends on EFI_STUB 1492 select DMA_COHERENT_POOL 1493 select ARCH_USE_MEMREMAP_PROT 1494 select INSTRUCTION_DECODER 1495 select ARCH_HAS_CC_PLATFORM 1496 select X86_MEM_ENCRYPT 1497 select UNACCEPTED_MEMORY 1498 select CRYPTO_LIB_AESGCM 1499 help 1500 Say yes to enable support for the encryption of system memory. 1501 This requires an AMD processor that supports Secure Memory 1502 Encryption (SME). 1503 1504# Common NUMA Features 1505config NUMA 1506 bool "NUMA Memory Allocation and Scheduler Support" 1507 depends on SMP 1508 depends on X86_64 1509 select USE_PERCPU_NUMA_NODE_ID 1510 select OF_NUMA if OF 1511 help 1512 Enable NUMA (Non-Uniform Memory Access) support. 1513 1514 The kernel will try to allocate memory used by a CPU on the 1515 local memory controller of the CPU and add some more 1516 NUMA awareness to the kernel. 1517 1518 For 64-bit this is recommended if the system is Intel Core i7 1519 (or later), AMD Opteron, or EM64T NUMA. 1520 1521 Otherwise, you should say N. 1522 1523config AMD_NUMA 1524 def_bool y 1525 prompt "Old style AMD Opteron NUMA detection" 1526 depends on X86_64 && NUMA && PCI 1527 help 1528 Enable AMD NUMA node topology detection. You should say Y here if 1529 you have a multi processor AMD system. This uses an old method to 1530 read the NUMA configuration directly from the builtin Northbridge 1531 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1532 which also takes priority if both are compiled in. 1533 1534config X86_64_ACPI_NUMA 1535 def_bool y 1536 prompt "ACPI NUMA detection" 1537 depends on X86_64 && NUMA && ACPI && PCI 1538 select ACPI_NUMA 1539 help 1540 Enable ACPI SRAT based node topology detection. 1541 1542config NODES_SHIFT 1543 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1544 range 1 10 1545 default "10" if MAXSMP 1546 default "6" if X86_64 1547 default "3" 1548 depends on NUMA 1549 help 1550 Specify the maximum number of NUMA Nodes available on the target 1551 system. Increases memory reserved to accommodate various tables. 1552 1553config ARCH_FLATMEM_ENABLE 1554 def_bool y 1555 depends on X86_32 && !NUMA 1556 1557config ARCH_SPARSEMEM_ENABLE 1558 def_bool y 1559 select SPARSEMEM_STATIC if X86_32 1560 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1561 1562config ARCH_SPARSEMEM_DEFAULT 1563 def_bool X86_64 || (NUMA && X86_32) 1564 1565config ARCH_SELECT_MEMORY_MODEL 1566 def_bool y 1567 depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE 1568 1569config ARCH_MEMORY_PROBE 1570 bool "Enable sysfs memory/probe interface" 1571 depends on MEMORY_HOTPLUG 1572 help 1573 This option enables a sysfs memory/probe interface for testing. 1574 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1575 If you are unsure how to answer this question, answer N. 1576 1577config ARCH_PROC_KCORE_TEXT 1578 def_bool y 1579 depends on X86_64 && PROC_KCORE 1580 1581config ILLEGAL_POINTER_VALUE 1582 hex 1583 default 0 if X86_32 1584 default 0xdead000000000000 if X86_64 1585 1586config X86_PMEM_LEGACY_DEVICE 1587 bool 1588 1589config X86_PMEM_LEGACY 1590 tristate "Support non-standard NVDIMMs and ADR protected memory" 1591 depends on PHYS_ADDR_T_64BIT 1592 depends on BLK_DEV 1593 select X86_PMEM_LEGACY_DEVICE 1594 select NUMA_KEEP_MEMINFO if NUMA 1595 select LIBNVDIMM 1596 help 1597 Treat memory marked using the non-standard e820 type of 12 as used 1598 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1599 The kernel will offer these regions to the 'pmem' driver so 1600 they can be used for persistent storage. 1601 1602 Say Y if unsure. 1603 1604config X86_CHECK_BIOS_CORRUPTION 1605 bool "Check for low memory corruption" 1606 help 1607 Periodically check for memory corruption in low memory, which 1608 is suspected to be caused by BIOS. Even when enabled in the 1609 configuration, it is disabled at runtime. Enable it by 1610 setting "memory_corruption_check=1" on the kernel command 1611 line. By default it scans the low 64k of memory every 60 1612 seconds; see the memory_corruption_check_size and 1613 memory_corruption_check_period parameters in 1614 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1615 1616 When enabled with the default parameters, this option has 1617 almost no overhead, as it reserves a relatively small amount 1618 of memory and scans it infrequently. It both detects corruption 1619 and prevents it from affecting the running system. 1620 1621 It is, however, intended as a diagnostic tool; if repeatable 1622 BIOS-originated corruption always affects the same memory, 1623 you can use memmap= to prevent the kernel from using that 1624 memory. 1625 1626config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1627 bool "Set the default setting of memory_corruption_check" 1628 depends on X86_CHECK_BIOS_CORRUPTION 1629 default y 1630 help 1631 Set whether the default state of memory_corruption_check is 1632 on or off. 1633 1634config MTRR 1635 def_bool y 1636 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1637 help 1638 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1639 the Memory Type Range Registers (MTRRs) may be used to control 1640 processor access to memory ranges. This is most useful if you have 1641 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1642 allows bus write transfers to be combined into a larger transfer 1643 before bursting over the PCI/AGP bus. This can increase performance 1644 of image write operations 2.5 times or more. Saying Y here creates a 1645 /proc/mtrr file which may be used to manipulate your processor's 1646 MTRRs. Typically the X server should use this. 1647 1648 This code has a reasonably generic interface so that similar 1649 control registers on other processors can be easily supported 1650 as well: 1651 1652 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1653 Registers (ARRs) which provide a similar functionality to MTRRs. For 1654 these, the ARRs are used to emulate the MTRRs. 1655 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1656 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1657 write-combining. All of these processors are supported by this code 1658 and it makes sense to say Y here if you have one of them. 1659 1660 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1661 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1662 can lead to all sorts of problems, so it's good to say Y here. 1663 1664 You can safely say Y even if your machine doesn't have MTRRs, you'll 1665 just add about 9 KB to your kernel. 1666 1667 See <file:Documentation/arch/x86/mtrr.rst> for more information. 1668 1669config MTRR_SANITIZER 1670 def_bool y 1671 prompt "MTRR cleanup support" 1672 depends on MTRR 1673 help 1674 Convert MTRR layout from continuous to discrete, so X drivers can 1675 add writeback entries. 1676 1677 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1678 The largest mtrr entry size for a continuous block can be set with 1679 mtrr_chunk_size. 1680 1681 If unsure, say Y. 1682 1683config MTRR_SANITIZER_ENABLE_DEFAULT 1684 int "MTRR cleanup enable value (0-1)" 1685 range 0 1 1686 default "0" 1687 depends on MTRR_SANITIZER 1688 help 1689 Enable mtrr cleanup default value 1690 1691config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1692 int "MTRR cleanup spare reg num (0-7)" 1693 range 0 7 1694 default "1" 1695 depends on MTRR_SANITIZER 1696 help 1697 mtrr cleanup spare entries default, it can be changed via 1698 mtrr_spare_reg_nr=N on the kernel command line. 1699 1700config X86_PAT 1701 def_bool y 1702 prompt "x86 PAT support" if EXPERT 1703 depends on MTRR 1704 select ARCH_USES_PG_ARCH_2 1705 help 1706 Use PAT attributes to setup page level cache control. 1707 1708 PATs are the modern equivalents of MTRRs and are much more 1709 flexible than MTRRs. 1710 1711 Say N here if you see bootup problems (boot crash, boot hang, 1712 spontaneous reboots) or a non-working video driver. 1713 1714 If unsure, say Y. 1715 1716config X86_UMIP 1717 def_bool y 1718 prompt "User Mode Instruction Prevention" if EXPERT 1719 help 1720 User Mode Instruction Prevention (UMIP) is a security feature in 1721 some x86 processors. If enabled, a general protection fault is 1722 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1723 executed in user mode. These instructions unnecessarily expose 1724 information about the hardware state. 1725 1726 The vast majority of applications do not use these instructions. 1727 For the very few that do, software emulation is provided in 1728 specific cases in protected and virtual-8086 modes. Emulated 1729 results are dummy. 1730 1731config CC_HAS_IBT 1732 # GCC >= 9 and binutils >= 2.29 1733 # Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654 1734 def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || CC_IS_CLANG) && \ 1735 $(as-instr,endbr64) 1736 1737config X86_CET 1738 def_bool n 1739 help 1740 CET features configured (Shadow stack or IBT) 1741 1742config X86_KERNEL_IBT 1743 prompt "Indirect Branch Tracking" 1744 def_bool y 1745 depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL 1746 select OBJTOOL 1747 select X86_CET 1748 help 1749 Build the kernel with support for Indirect Branch Tracking, a 1750 hardware support course-grain forward-edge Control Flow Integrity 1751 protection. It enforces that all indirect calls must land on 1752 an ENDBR instruction, as such, the compiler will instrument the 1753 code with them to make this happen. 1754 1755 In addition to building the kernel with IBT, seal all functions that 1756 are not indirect call targets, avoiding them ever becoming one. 1757 1758 This requires LTO like objtool runs and will slow down the build. It 1759 does significantly reduce the number of ENDBR instructions in the 1760 kernel image. 1761 1762config X86_INTEL_MEMORY_PROTECTION_KEYS 1763 prompt "Memory Protection Keys" 1764 def_bool y 1765 # Note: only available in 64-bit mode 1766 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1767 select ARCH_USES_HIGH_VMA_FLAGS 1768 select ARCH_HAS_PKEYS 1769 help 1770 Memory Protection Keys provides a mechanism for enforcing 1771 page-based protections, but without requiring modification of the 1772 page tables when an application changes protection domains. 1773 1774 For details, see Documentation/core-api/protection-keys.rst 1775 1776 If unsure, say y. 1777 1778config ARCH_PKEY_BITS 1779 int 1780 default 4 1781 1782choice 1783 prompt "TSX enable mode" 1784 depends on CPU_SUP_INTEL 1785 default X86_INTEL_TSX_MODE_AUTO 1786 help 1787 Intel's TSX (Transactional Synchronization Extensions) feature 1788 allows to optimize locking protocols through lock elision which 1789 can lead to a noticeable performance boost. 1790 1791 On the other hand it has been shown that TSX can be exploited 1792 to form side channel attacks (e.g. TAA) and chances are there 1793 will be more of those attacks discovered in the future. 1794 1795 Therefore TSX is not enabled by default (aka tsx=off). An admin 1796 might override this decision by tsx=on the command line parameter. 1797 Even with TSX enabled, the kernel will attempt to enable the best 1798 possible TAA mitigation setting depending on the microcode available 1799 for the particular machine. 1800 1801 This option allows to set the default tsx mode between tsx=on, =off 1802 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1803 details. 1804 1805 Say off if not sure, auto if TSX is in use but it should be used on safe 1806 platforms or on if TSX is in use and the security aspect of tsx is not 1807 relevant. 1808 1809config X86_INTEL_TSX_MODE_OFF 1810 bool "off" 1811 help 1812 TSX is disabled if possible - equals to tsx=off command line parameter. 1813 1814config X86_INTEL_TSX_MODE_ON 1815 bool "on" 1816 help 1817 TSX is always enabled on TSX capable HW - equals the tsx=on command 1818 line parameter. 1819 1820config X86_INTEL_TSX_MODE_AUTO 1821 bool "auto" 1822 help 1823 TSX is enabled on TSX capable HW that is believed to be safe against 1824 side channel attacks- equals the tsx=auto command line parameter. 1825endchoice 1826 1827config X86_SGX 1828 bool "Software Guard eXtensions (SGX)" 1829 depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC 1830 select CRYPTO_LIB_SHA256 1831 select MMU_NOTIFIER 1832 select NUMA_KEEP_MEMINFO if NUMA 1833 select XARRAY_MULTI 1834 help 1835 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1836 that can be used by applications to set aside private regions of code 1837 and data, referred to as enclaves. An enclave's private memory can 1838 only be accessed by code running within the enclave. Accesses from 1839 outside the enclave, including other enclaves, are disallowed by 1840 hardware. 1841 1842 If unsure, say N. 1843 1844config X86_USER_SHADOW_STACK 1845 bool "X86 userspace shadow stack" 1846 depends on AS_WRUSS 1847 depends on X86_64 1848 depends on PER_VMA_LOCK 1849 select ARCH_USES_HIGH_VMA_FLAGS 1850 select ARCH_HAS_USER_SHADOW_STACK 1851 select X86_CET 1852 help 1853 Shadow stack protection is a hardware feature that detects function 1854 return address corruption. This helps mitigate ROP attacks. 1855 Applications must be enabled to use it, and old userspace does not 1856 get protection "for free". 1857 1858 CPUs supporting shadow stacks were first released in 2020. 1859 1860 See Documentation/arch/x86/shstk.rst for more information. 1861 1862 If unsure, say N. 1863 1864config INTEL_TDX_HOST 1865 bool "Intel Trust Domain Extensions (TDX) host support" 1866 depends on CPU_SUP_INTEL 1867 depends on X86_64 1868 depends on KVM_INTEL 1869 depends on X86_X2APIC 1870 select ARCH_KEEP_MEMBLOCK 1871 depends on CONTIG_ALLOC 1872 depends on X86_MCE 1873 help 1874 Intel Trust Domain Extensions (TDX) protects guest VMs from malicious 1875 host and certain physical attacks. This option enables necessary TDX 1876 support in the host kernel to run confidential VMs. 1877 1878 If unsure, say N. 1879 1880config EFI 1881 bool "EFI runtime service support" 1882 depends on ACPI 1883 select UCS2_STRING 1884 select EFI_RUNTIME_WRAPPERS 1885 select ARCH_USE_MEMREMAP_PROT 1886 select EFI_RUNTIME_MAP if KEXEC_CORE 1887 help 1888 This enables the kernel to use EFI runtime services that are 1889 available (such as the EFI variable services). 1890 1891 This option is only useful on systems that have EFI firmware. 1892 In addition, you should use the latest ELILO loader available 1893 at <http://elilo.sourceforge.net> in order to take advantage 1894 of EFI runtime services. However, even with this option, the 1895 resultant kernel should continue to boot on existing non-EFI 1896 platforms. 1897 1898config EFI_STUB 1899 bool "EFI stub support" 1900 depends on EFI 1901 select RELOCATABLE 1902 help 1903 This kernel feature allows a bzImage to be loaded directly 1904 by EFI firmware without the use of a bootloader. 1905 1906 See Documentation/admin-guide/efi-stub.rst for more information. 1907 1908config EFI_HANDOVER_PROTOCOL 1909 bool "EFI handover protocol (DEPRECATED)" 1910 depends on EFI_STUB 1911 default y 1912 help 1913 Select this in order to include support for the deprecated EFI 1914 handover protocol, which defines alternative entry points into the 1915 EFI stub. This is a practice that has no basis in the UEFI 1916 specification, and requires a priori knowledge on the part of the 1917 bootloader about Linux/x86 specific ways of passing the command line 1918 and initrd, and where in memory those assets may be loaded. 1919 1920 If in doubt, say Y. Even though the corresponding support is not 1921 present in upstream GRUB or other bootloaders, most distros build 1922 GRUB with numerous downstream patches applied, and may rely on the 1923 handover protocol as as result. 1924 1925config EFI_MIXED 1926 bool "EFI mixed-mode support" 1927 depends on EFI_STUB && X86_64 1928 help 1929 Enabling this feature allows a 64-bit kernel to be booted 1930 on a 32-bit firmware, provided that your CPU supports 64-bit 1931 mode. 1932 1933 Note that it is not possible to boot a mixed-mode enabled 1934 kernel via the EFI boot stub - a bootloader that supports 1935 the EFI handover protocol must be used. 1936 1937 If unsure, say N. 1938 1939config EFI_RUNTIME_MAP 1940 bool "Export EFI runtime maps to sysfs" if EXPERT 1941 depends on EFI 1942 help 1943 Export EFI runtime memory regions to /sys/firmware/efi/runtime-map. 1944 That memory map is required by the 2nd kernel to set up EFI virtual 1945 mappings after kexec, but can also be used for debugging purposes. 1946 1947 See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map. 1948 1949source "kernel/Kconfig.hz" 1950 1951config ARCH_SUPPORTS_KEXEC 1952 def_bool y 1953 1954config ARCH_SUPPORTS_KEXEC_FILE 1955 def_bool X86_64 1956 1957config ARCH_SELECTS_KEXEC_FILE 1958 def_bool y 1959 depends on KEXEC_FILE 1960 select HAVE_IMA_KEXEC if IMA 1961 1962config ARCH_SUPPORTS_KEXEC_PURGATORY 1963 def_bool y 1964 1965config ARCH_SUPPORTS_KEXEC_SIG 1966 def_bool y 1967 1968config ARCH_SUPPORTS_KEXEC_SIG_FORCE 1969 def_bool y 1970 1971config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG 1972 def_bool y 1973 1974config ARCH_SUPPORTS_KEXEC_JUMP 1975 def_bool y 1976 1977config ARCH_SUPPORTS_KEXEC_HANDOVER 1978 def_bool X86_64 1979 1980config ARCH_SUPPORTS_CRASH_DUMP 1981 def_bool X86_64 || (X86_32 && HIGHMEM) 1982 1983config ARCH_DEFAULT_CRASH_DUMP 1984 def_bool y 1985 1986config ARCH_SUPPORTS_CRASH_HOTPLUG 1987 def_bool y 1988 1989config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION 1990 def_bool CRASH_RESERVE 1991 1992config PHYSICAL_START 1993 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 1994 default "0x1000000" 1995 help 1996 This gives the physical address where the kernel is loaded. 1997 1998 If the kernel is not relocatable (CONFIG_RELOCATABLE=n) then bzImage 1999 will decompress itself to above physical address and run from there. 2000 Otherwise, bzImage will run from the address where it has been loaded 2001 by the boot loader. The only exception is if it is loaded below the 2002 above physical address, in which case it will relocate itself there. 2003 2004 In normal kdump cases one does not have to set/change this option 2005 as now bzImage can be compiled as a completely relocatable image 2006 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2007 address. This option is mainly useful for the folks who don't want 2008 to use a bzImage for capturing the crash dump and want to use a 2009 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2010 to be specifically compiled to run from a specific memory area 2011 (normally a reserved region) and this option comes handy. 2012 2013 So if you are using bzImage for capturing the crash dump, 2014 leave the value here unchanged to 0x1000000 and set 2015 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2016 for capturing the crash dump change this value to start of 2017 the reserved region. In other words, it can be set based on 2018 the "X" value as specified in the "crashkernel=YM@XM" 2019 command line boot parameter passed to the panic-ed 2020 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2021 for more details about crash dumps. 2022 2023 Usage of bzImage for capturing the crash dump is recommended as 2024 one does not have to build two kernels. Same kernel can be used 2025 as production kernel and capture kernel. Above option should have 2026 gone away after relocatable bzImage support is introduced. But it 2027 is present because there are users out there who continue to use 2028 vmlinux for dump capture. This option should go away down the 2029 line. 2030 2031 Don't change this unless you know what you are doing. 2032 2033config RELOCATABLE 2034 bool "Build a relocatable kernel" 2035 default y 2036 help 2037 This builds a kernel image that retains relocation information 2038 so it can be loaded someplace besides the default 1MB. 2039 The relocations tend to make the kernel binary about 10% larger, 2040 but are discarded at runtime. 2041 2042 One use is for the kexec on panic case where the recovery kernel 2043 must live at a different physical address than the primary 2044 kernel. 2045 2046 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2047 it has been loaded at and the compile time physical address 2048 (CONFIG_PHYSICAL_START) is used as the minimum location. 2049 2050config RANDOMIZE_BASE 2051 bool "Randomize the address of the kernel image (KASLR)" 2052 depends on RELOCATABLE 2053 default y 2054 help 2055 In support of Kernel Address Space Layout Randomization (KASLR), 2056 this randomizes the physical address at which the kernel image 2057 is decompressed and the virtual address where the kernel 2058 image is mapped, as a security feature that deters exploit 2059 attempts relying on knowledge of the location of kernel 2060 code internals. 2061 2062 On 64-bit, the kernel physical and virtual addresses are 2063 randomized separately. The physical address will be anywhere 2064 between 16MB and the top of physical memory (up to 64TB). The 2065 virtual address will be randomized from 16MB up to 1GB (9 bits 2066 of entropy). Note that this also reduces the memory space 2067 available to kernel modules from 1.5GB to 1GB. 2068 2069 On 32-bit, the kernel physical and virtual addresses are 2070 randomized together. They will be randomized from 16MB up to 2071 512MB (8 bits of entropy). 2072 2073 Entropy is generated using the RDRAND instruction if it is 2074 supported. If RDTSC is supported, its value is mixed into 2075 the entropy pool as well. If neither RDRAND nor RDTSC are 2076 supported, then entropy is read from the i8254 timer. The 2077 usable entropy is limited by the kernel being built using 2078 2GB addressing, and that PHYSICAL_ALIGN must be at a 2079 minimum of 2MB. As a result, only 10 bits of entropy are 2080 theoretically possible, but the implementations are further 2081 limited due to memory layouts. 2082 2083 If unsure, say Y. 2084 2085# Relocation on x86 needs some additional build support 2086config X86_NEED_RELOCS 2087 def_bool y 2088 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2089 select ARCH_VMLINUX_NEEDS_RELOCS 2090 2091config PHYSICAL_ALIGN 2092 hex "Alignment value to which kernel should be aligned" 2093 default "0x200000" 2094 range 0x2000 0x1000000 if X86_32 2095 range 0x200000 0x1000000 if X86_64 2096 help 2097 This value puts the alignment restrictions on physical address 2098 where kernel is loaded and run from. Kernel is compiled for an 2099 address which meets above alignment restriction. 2100 2101 If bootloader loads the kernel at a non-aligned address and 2102 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2103 address aligned to above value and run from there. 2104 2105 If bootloader loads the kernel at a non-aligned address and 2106 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2107 load address and decompress itself to the address it has been 2108 compiled for and run from there. The address for which kernel is 2109 compiled already meets above alignment restrictions. Hence the 2110 end result is that kernel runs from a physical address meeting 2111 above alignment restrictions. 2112 2113 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2114 this value must be a multiple of 0x200000. 2115 2116 Don't change this unless you know what you are doing. 2117 2118config RANDOMIZE_MEMORY 2119 bool "Randomize the kernel memory sections" 2120 depends on X86_64 2121 depends on RANDOMIZE_BASE 2122 default RANDOMIZE_BASE 2123 help 2124 Randomizes the base virtual address of kernel memory sections 2125 (physical memory mapping, vmalloc & vmemmap). This security feature 2126 makes exploits relying on predictable memory locations less reliable. 2127 2128 The order of allocations remains unchanged. Entropy is generated in 2129 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2130 configuration have in average 30,000 different possible virtual 2131 addresses for each memory section. 2132 2133 If unsure, say Y. 2134 2135config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2136 hex "Physical memory mapping padding" if EXPERT 2137 depends on RANDOMIZE_MEMORY 2138 default "0xa" if MEMORY_HOTPLUG 2139 default "0x0" 2140 range 0x1 0x40 if MEMORY_HOTPLUG 2141 range 0x0 0x40 2142 help 2143 Define the padding in terabytes added to the existing physical 2144 memory size during kernel memory randomization. It is useful 2145 for memory hotplug support but reduces the entropy available for 2146 address randomization. 2147 2148 If unsure, leave at the default value. 2149 2150config ADDRESS_MASKING 2151 bool "Linear Address Masking support" 2152 depends on X86_64 2153 depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS 2154 help 2155 Linear Address Masking (LAM) modifies the checking that is applied 2156 to 64-bit linear addresses, allowing software to use of the 2157 untranslated address bits for metadata. 2158 2159 The capability can be used for efficient address sanitizers (ASAN) 2160 implementation and for optimizations in JITs. 2161 2162config HOTPLUG_CPU 2163 def_bool y 2164 depends on SMP 2165 2166config COMPAT_VDSO 2167 def_bool n 2168 prompt "Workaround for glibc 2.3.2 / 2.3.3 (released in year 2003/2004)" 2169 depends on COMPAT_32 2170 help 2171 Certain buggy versions of glibc will crash if they are 2172 presented with a 32-bit vDSO that is not mapped at the address 2173 indicated in its segment table. 2174 2175 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2176 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2177 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2178 the only released version with the bug, but OpenSUSE 9 2179 contains a buggy "glibc 2.3.2". 2180 2181 The symptom of the bug is that everything crashes on startup, saying: 2182 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2183 2184 Saying Y here changes the default value of the vdso32 boot 2185 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2186 This works around the glibc bug but hurts performance. 2187 2188 If unsure, say N: if you are compiling your own kernel, you 2189 are unlikely to be using a buggy version of glibc. 2190 2191choice 2192 prompt "vsyscall table for legacy applications" 2193 depends on X86_64 2194 default LEGACY_VSYSCALL_XONLY 2195 help 2196 Legacy user code that does not know how to find the vDSO expects 2197 to be able to issue three syscalls by calling fixed addresses in 2198 kernel space. Since this location is not randomized with ASLR, 2199 it can be used to assist security vulnerability exploitation. 2200 2201 This setting can be changed at boot time via the kernel command 2202 line parameter vsyscall=[emulate|xonly|none]. Emulate mode 2203 is deprecated and can only be enabled using the kernel command 2204 line. 2205 2206 On a system with recent enough glibc (2.14 or newer) and no 2207 static binaries, you can say None without a performance penalty 2208 to improve security. 2209 2210 If unsure, select "Emulate execution only". 2211 2212 config LEGACY_VSYSCALL_XONLY 2213 bool "Emulate execution only" 2214 help 2215 The kernel traps and emulates calls into the fixed vsyscall 2216 address mapping and does not allow reads. This 2217 configuration is recommended when userspace might use the 2218 legacy vsyscall area but support for legacy binary 2219 instrumentation of legacy code is not needed. It mitigates 2220 certain uses of the vsyscall area as an ASLR-bypassing 2221 buffer. 2222 2223 config LEGACY_VSYSCALL_NONE 2224 bool "None" 2225 help 2226 There will be no vsyscall mapping at all. This will 2227 eliminate any risk of ASLR bypass due to the vsyscall 2228 fixed address mapping. Attempts to use the vsyscalls 2229 will be reported to dmesg, so that either old or 2230 malicious userspace programs can be identified. 2231 2232endchoice 2233 2234config CMDLINE_BOOL 2235 bool "Built-in kernel command line" 2236 help 2237 Allow for specifying boot arguments to the kernel at 2238 build time. On some systems (e.g. embedded ones), it is 2239 necessary or convenient to provide some or all of the 2240 kernel boot arguments with the kernel itself (that is, 2241 to not rely on the boot loader to provide them.) 2242 2243 To compile command line arguments into the kernel, 2244 set this option to 'Y', then fill in the 2245 boot arguments in CONFIG_CMDLINE. 2246 2247 Systems with fully functional boot loaders (i.e. non-embedded) 2248 should leave this option set to 'N'. 2249 2250config CMDLINE 2251 string "Built-in kernel command string" 2252 depends on CMDLINE_BOOL 2253 default "" 2254 help 2255 Enter arguments here that should be compiled into the kernel 2256 image and used at boot time. If the boot loader provides a 2257 command line at boot time, it is appended to this string to 2258 form the full kernel command line, when the system boots. 2259 2260 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2261 change this behavior. 2262 2263 In most cases, the command line (whether built-in or provided 2264 by the boot loader) should specify the device for the root 2265 file system. 2266 2267config CMDLINE_OVERRIDE 2268 bool "Built-in command line overrides boot loader arguments" 2269 depends on CMDLINE_BOOL && CMDLINE != "" 2270 help 2271 Set this option to 'Y' to have the kernel ignore the boot loader 2272 command line, and use ONLY the built-in command line. 2273 2274 This is used to work around broken boot loaders. This should 2275 be set to 'N' under normal conditions. 2276 2277config MODIFY_LDT_SYSCALL 2278 bool "Enable the LDT (local descriptor table)" if EXPERT 2279 default y 2280 help 2281 Linux can allow user programs to install a per-process x86 2282 Local Descriptor Table (LDT) using the modify_ldt(2) system 2283 call. This is required to run 16-bit or segmented code such as 2284 DOSEMU or some Wine programs. It is also used by some very old 2285 threading libraries. 2286 2287 Enabling this feature adds a small amount of overhead to 2288 context switches and increases the low-level kernel attack 2289 surface. Disabling it removes the modify_ldt(2) system call. 2290 2291 Saying 'N' here may make sense for embedded or server kernels. 2292 2293config STRICT_SIGALTSTACK_SIZE 2294 bool "Enforce strict size checking for sigaltstack" 2295 depends on DYNAMIC_SIGFRAME 2296 help 2297 For historical reasons MINSIGSTKSZ is a constant which became 2298 already too small with AVX512 support. Add a mechanism to 2299 enforce strict checking of the sigaltstack size against the 2300 real size of the FPU frame. This option enables the check 2301 by default. It can also be controlled via the kernel command 2302 line option 'strict_sas_size' independent of this config 2303 switch. Enabling it might break existing applications which 2304 allocate a too small sigaltstack but 'work' because they 2305 never get a signal delivered. 2306 2307 Say 'N' unless you want to really enforce this check. 2308 2309config CFI_AUTO_DEFAULT 2310 bool "Attempt to use FineIBT by default at boot time" 2311 depends on FINEIBT 2312 depends on !RUST || RUSTC_VERSION >= 108800 2313 default y 2314 help 2315 Attempt to use FineIBT by default at boot time. If enabled, 2316 this is the same as booting with "cfi=auto". If disabled, 2317 this is the same as booting with "cfi=kcfi". 2318 2319source "kernel/livepatch/Kconfig" 2320 2321config X86_BUS_LOCK_DETECT 2322 bool "Split Lock Detect and Bus Lock Detect support" 2323 depends on CPU_SUP_INTEL || CPU_SUP_AMD 2324 default y 2325 help 2326 Enable Split Lock Detect and Bus Lock Detect functionalities. 2327 See <file:Documentation/arch/x86/buslock.rst> for more information. 2328 2329endmenu 2330 2331config CC_HAS_NAMED_AS 2332 def_bool $(success,echo 'int __seg_fs fs; int __seg_gs gs;' | $(CC) -x c - -S -o /dev/null) 2333 depends on CC_IS_GCC 2334 2335# 2336# -fsanitize=kernel-address (KASAN) and -fsanitize=thread (KCSAN) 2337# are incompatible with named address spaces with GCC < 13.3 2338# (see GCC PR sanitizer/111736 and also PR sanitizer/115172). 2339# 2340 2341config CC_HAS_NAMED_AS_FIXED_SANITIZERS 2342 def_bool y 2343 depends on !(KASAN || KCSAN) || GCC_VERSION >= 130300 2344 depends on !(UBSAN_BOOL && KASAN) || GCC_VERSION >= 140200 2345 2346config USE_X86_SEG_SUPPORT 2347 def_bool CC_HAS_NAMED_AS 2348 depends on CC_HAS_NAMED_AS_FIXED_SANITIZERS 2349 2350config CC_HAS_SLS 2351 def_bool $(cc-option,-mharden-sls=all) 2352 2353config CC_HAS_RETURN_THUNK 2354 def_bool $(cc-option,-mfunction-return=thunk-extern) 2355 2356config CC_HAS_ENTRY_PADDING 2357 def_bool $(cc-option,-fpatchable-function-entry=16,16) 2358 2359config CC_HAS_KCFI_ARITY 2360 def_bool $(cc-option,-fsanitize=kcfi -fsanitize-kcfi-arity) 2361 depends on CC_IS_CLANG && !RUST 2362 2363config FUNCTION_PADDING_CFI 2364 int 2365 default 59 if FUNCTION_ALIGNMENT_64B 2366 default 27 if FUNCTION_ALIGNMENT_32B 2367 default 11 if FUNCTION_ALIGNMENT_16B 2368 default 3 if FUNCTION_ALIGNMENT_8B 2369 default 0 2370 2371# Basically: FUNCTION_ALIGNMENT - 5*CFI 2372# except Kconfig can't do arithmetic :/ 2373config FUNCTION_PADDING_BYTES 2374 int 2375 default FUNCTION_PADDING_CFI if CFI 2376 default FUNCTION_ALIGNMENT 2377 2378config CALL_PADDING 2379 def_bool n 2380 depends on CC_HAS_ENTRY_PADDING && OBJTOOL 2381 select FUNCTION_ALIGNMENT_16B 2382 2383config FINEIBT 2384 def_bool y 2385 depends on X86_KERNEL_IBT && CFI && MITIGATION_RETPOLINE 2386 select CALL_PADDING 2387 2388config FINEIBT_BHI 2389 def_bool y 2390 depends on FINEIBT && CC_HAS_KCFI_ARITY 2391 2392config HAVE_CALL_THUNKS 2393 def_bool y 2394 depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL 2395 2396config CALL_THUNKS 2397 def_bool n 2398 select CALL_PADDING 2399 2400menuconfig CPU_MITIGATIONS 2401 bool "Mitigations for CPU vulnerabilities" 2402 default y 2403 help 2404 Say Y here to enable options which enable mitigations for hardware 2405 vulnerabilities (usually related to speculative execution). 2406 Mitigations can be disabled or restricted to SMT systems at runtime 2407 via the "mitigations" kernel parameter. 2408 2409 If you say N, all mitigations will be disabled. This CANNOT be 2410 overridden at runtime. 2411 2412 Say 'Y', unless you really know what you are doing. 2413 2414if CPU_MITIGATIONS 2415 2416config MITIGATION_PAGE_TABLE_ISOLATION 2417 bool "Remove the kernel mapping in user mode" 2418 default y 2419 depends on (X86_64 || X86_PAE) 2420 help 2421 This feature reduces the number of hardware side channels by 2422 ensuring that the majority of kernel addresses are not mapped 2423 into userspace. 2424 2425 See Documentation/arch/x86/pti.rst for more details. 2426 2427config MITIGATION_RETPOLINE 2428 bool "Avoid speculative indirect branches in kernel" 2429 select OBJTOOL if HAVE_OBJTOOL 2430 default y 2431 help 2432 Compile kernel with the retpoline compiler options to guard against 2433 kernel-to-user data leaks by avoiding speculative indirect 2434 branches. Requires a compiler with -mindirect-branch=thunk-extern 2435 support for full protection. The kernel may run slower. 2436 2437config MITIGATION_RETHUNK 2438 bool "Enable return-thunks" 2439 depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK 2440 select OBJTOOL if HAVE_OBJTOOL 2441 default y if X86_64 2442 help 2443 Compile the kernel with the return-thunks compiler option to guard 2444 against kernel-to-user data leaks by avoiding return speculation. 2445 Requires a compiler with -mfunction-return=thunk-extern 2446 support for full protection. The kernel may run slower. 2447 2448config MITIGATION_UNRET_ENTRY 2449 bool "Enable UNRET on kernel entry" 2450 depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64 2451 default y 2452 help 2453 Compile the kernel with support for the retbleed=unret mitigation. 2454 2455config MITIGATION_CALL_DEPTH_TRACKING 2456 bool "Mitigate RSB underflow with call depth tracking" 2457 depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS 2458 select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 2459 select CALL_THUNKS 2460 default y 2461 help 2462 Compile the kernel with call depth tracking to mitigate the Intel 2463 SKL Return-Stack-Buffer (RSB) underflow issue. The mitigation is off 2464 by default and needs to be enabled on the kernel command line via the 2465 retbleed=stuff option. For non-affected systems the overhead of this 2466 option is marginal as the call depth tracking is using run-time 2467 generated call thunks in a compiler generated padding area and call 2468 patching. This increases text size by ~5%. For non affected systems 2469 this space is unused. On affected SKL systems this results in a 2470 significant performance gain over the IBRS mitigation. 2471 2472config CALL_THUNKS_DEBUG 2473 bool "Enable call thunks and call depth tracking debugging" 2474 depends on MITIGATION_CALL_DEPTH_TRACKING 2475 select FUNCTION_ALIGNMENT_32B 2476 default n 2477 help 2478 Enable call/ret counters for imbalance detection and build in 2479 a noisy dmesg about callthunks generation and call patching for 2480 trouble shooting. The debug prints need to be enabled on the 2481 kernel command line with 'debug-callthunks'. 2482 Only enable this when you are debugging call thunks as this 2483 creates a noticeable runtime overhead. If unsure say N. 2484 2485config MITIGATION_IBPB_ENTRY 2486 bool "Enable IBPB on kernel entry" 2487 depends on CPU_SUP_AMD && X86_64 2488 default y 2489 help 2490 Compile the kernel with support for the retbleed=ibpb and 2491 spec_rstack_overflow={ibpb,ibpb-vmexit} mitigations. 2492 2493config MITIGATION_IBRS_ENTRY 2494 bool "Enable IBRS on kernel entry" 2495 depends on CPU_SUP_INTEL && X86_64 2496 default y 2497 help 2498 Compile the kernel with support for the spectre_v2=ibrs mitigation. 2499 This mitigates both spectre_v2 and retbleed at great cost to 2500 performance. 2501 2502config MITIGATION_SRSO 2503 bool "Mitigate speculative RAS overflow on AMD" 2504 depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK 2505 default y 2506 help 2507 Enable the SRSO mitigation needed on AMD Zen1-4 machines. 2508 2509config MITIGATION_SLS 2510 bool "Mitigate Straight-Line-Speculation" 2511 depends on CC_HAS_SLS && X86_64 2512 select OBJTOOL if HAVE_OBJTOOL 2513 default n 2514 help 2515 Compile the kernel with straight-line-speculation options to guard 2516 against straight line speculation. The kernel image might be slightly 2517 larger. 2518 2519config MITIGATION_GDS 2520 bool "Mitigate Gather Data Sampling" 2521 depends on CPU_SUP_INTEL 2522 default y 2523 help 2524 Enable mitigation for Gather Data Sampling (GDS). GDS is a hardware 2525 vulnerability which allows unprivileged speculative access to data 2526 which was previously stored in vector registers. The attacker uses gather 2527 instructions to infer the stale vector register data. 2528 2529config MITIGATION_RFDS 2530 bool "RFDS Mitigation" 2531 depends on CPU_SUP_INTEL 2532 default y 2533 help 2534 Enable mitigation for Register File Data Sampling (RFDS) by default. 2535 RFDS is a hardware vulnerability which affects Intel Atom CPUs. It 2536 allows unprivileged speculative access to stale data previously 2537 stored in floating point, vector and integer registers. 2538 See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst> 2539 2540config MITIGATION_SPECTRE_BHI 2541 bool "Mitigate Spectre-BHB (Branch History Injection)" 2542 depends on CPU_SUP_INTEL 2543 default y 2544 help 2545 Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks 2546 where the branch history buffer is poisoned to speculatively steer 2547 indirect branches. 2548 See <file:Documentation/admin-guide/hw-vuln/spectre.rst> 2549 2550config MITIGATION_MDS 2551 bool "Mitigate Microarchitectural Data Sampling (MDS) hardware bug" 2552 depends on CPU_SUP_INTEL 2553 default y 2554 help 2555 Enable mitigation for Microarchitectural Data Sampling (MDS). MDS is 2556 a hardware vulnerability which allows unprivileged speculative access 2557 to data which is available in various CPU internal buffers. 2558 See also <file:Documentation/admin-guide/hw-vuln/mds.rst> 2559 2560config MITIGATION_TAA 2561 bool "Mitigate TSX Asynchronous Abort (TAA) hardware bug" 2562 depends on CPU_SUP_INTEL 2563 default y 2564 help 2565 Enable mitigation for TSX Asynchronous Abort (TAA). TAA is a hardware 2566 vulnerability that allows unprivileged speculative access to data 2567 which is available in various CPU internal buffers by using 2568 asynchronous aborts within an Intel TSX transactional region. 2569 See also <file:Documentation/admin-guide/hw-vuln/tsx_async_abort.rst> 2570 2571config MITIGATION_MMIO_STALE_DATA 2572 bool "Mitigate MMIO Stale Data hardware bug" 2573 depends on CPU_SUP_INTEL 2574 default y 2575 help 2576 Enable mitigation for MMIO Stale Data hardware bugs. Processor MMIO 2577 Stale Data Vulnerabilities are a class of memory-mapped I/O (MMIO) 2578 vulnerabilities that can expose data. The vulnerabilities require the 2579 attacker to have access to MMIO. 2580 See also 2581 <file:Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst> 2582 2583config MITIGATION_L1TF 2584 bool "Mitigate L1 Terminal Fault (L1TF) hardware bug" 2585 depends on CPU_SUP_INTEL 2586 default y 2587 help 2588 Mitigate L1 Terminal Fault (L1TF) hardware bug. L1 Terminal Fault is a 2589 hardware vulnerability which allows unprivileged speculative access to data 2590 available in the Level 1 Data Cache. 2591 See <file:Documentation/admin-guide/hw-vuln/l1tf.rst 2592 2593config MITIGATION_RETBLEED 2594 bool "Mitigate RETBleed hardware bug" 2595 depends on (CPU_SUP_INTEL && MITIGATION_SPECTRE_V2) || MITIGATION_UNRET_ENTRY || MITIGATION_IBPB_ENTRY 2596 default y 2597 help 2598 Enable mitigation for RETBleed (Arbitrary Speculative Code Execution 2599 with Return Instructions) vulnerability. RETBleed is a speculative 2600 execution attack which takes advantage of microarchitectural behavior 2601 in many modern microprocessors, similar to Spectre v2. An 2602 unprivileged attacker can use these flaws to bypass conventional 2603 memory security restrictions to gain read access to privileged memory 2604 that would otherwise be inaccessible. 2605 2606config MITIGATION_SPECTRE_V1 2607 bool "Mitigate SPECTRE V1 hardware bug" 2608 default y 2609 help 2610 Enable mitigation for Spectre V1 (Bounds Check Bypass). Spectre V1 is a 2611 class of side channel attacks that takes advantage of speculative 2612 execution that bypasses conditional branch instructions used for 2613 memory access bounds check. 2614 See also <file:Documentation/admin-guide/hw-vuln/spectre.rst> 2615 2616config MITIGATION_SPECTRE_V2 2617 bool "Mitigate SPECTRE V2 hardware bug" 2618 default y 2619 help 2620 Enable mitigation for Spectre V2 (Branch Target Injection). Spectre 2621 V2 is a class of side channel attacks that takes advantage of 2622 indirect branch predictors inside the processor. In Spectre variant 2 2623 attacks, the attacker can steer speculative indirect branches in the 2624 victim to gadget code by poisoning the branch target buffer of a CPU 2625 used for predicting indirect branch addresses. 2626 See also <file:Documentation/admin-guide/hw-vuln/spectre.rst> 2627 2628config MITIGATION_SRBDS 2629 bool "Mitigate Special Register Buffer Data Sampling (SRBDS) hardware bug" 2630 depends on CPU_SUP_INTEL 2631 default y 2632 help 2633 Enable mitigation for Special Register Buffer Data Sampling (SRBDS). 2634 SRBDS is a hardware vulnerability that allows Microarchitectural Data 2635 Sampling (MDS) techniques to infer values returned from special 2636 register accesses. An unprivileged user can extract values returned 2637 from RDRAND and RDSEED executed on another core or sibling thread 2638 using MDS techniques. 2639 See also 2640 <file:Documentation/admin-guide/hw-vuln/special-register-buffer-data-sampling.rst> 2641 2642config MITIGATION_SSB 2643 bool "Mitigate Speculative Store Bypass (SSB) hardware bug" 2644 default y 2645 help 2646 Enable mitigation for Speculative Store Bypass (SSB). SSB is a 2647 hardware security vulnerability and its exploitation takes advantage 2648 of speculative execution in a similar way to the Meltdown and Spectre 2649 security vulnerabilities. 2650 2651config MITIGATION_ITS 2652 bool "Enable Indirect Target Selection mitigation" 2653 depends on CPU_SUP_INTEL && X86_64 2654 depends on MITIGATION_RETPOLINE && MITIGATION_RETHUNK 2655 select EXECMEM 2656 default y 2657 help 2658 Enable Indirect Target Selection (ITS) mitigation. ITS is a bug in 2659 BPU on some Intel CPUs that may allow Spectre V2 style attacks. If 2660 disabled, mitigation cannot be enabled via cmdline. 2661 See <file:Documentation/admin-guide/hw-vuln/indirect-target-selection.rst> 2662 2663config MITIGATION_TSA 2664 bool "Mitigate Transient Scheduler Attacks" 2665 depends on CPU_SUP_AMD 2666 default y 2667 help 2668 Enable mitigation for Transient Scheduler Attacks. TSA is a hardware 2669 security vulnerability on AMD CPUs which can lead to forwarding of 2670 invalid info to subsequent instructions and thus can affect their 2671 timing and thereby cause a leakage. 2672 2673config MITIGATION_VMSCAPE 2674 bool "Mitigate VMSCAPE" 2675 depends on KVM 2676 default y 2677 help 2678 Enable mitigation for VMSCAPE attacks. VMSCAPE is a hardware security 2679 vulnerability on Intel and AMD CPUs that may allow a guest to do 2680 Spectre v2 style attacks on userspace hypervisor. 2681endif 2682 2683config ARCH_HAS_ADD_PAGES 2684 def_bool y 2685 depends on ARCH_ENABLE_MEMORY_HOTPLUG 2686 2687menu "Power management and ACPI options" 2688 2689config ARCH_HIBERNATION_HEADER 2690 def_bool y 2691 depends on HIBERNATION 2692 2693source "kernel/power/Kconfig" 2694 2695source "drivers/acpi/Kconfig" 2696 2697config X86_APM_BOOT 2698 def_bool y 2699 depends on APM 2700 2701menuconfig APM 2702 tristate "APM (Advanced Power Management) BIOS support" 2703 depends on X86_32 && PM_SLEEP 2704 help 2705 APM is a BIOS specification for saving power using several different 2706 techniques. This is mostly useful for battery powered laptops with 2707 APM compliant BIOSes. If you say Y here, the system time will be 2708 reset after a RESUME operation, the /proc/apm device will provide 2709 battery status information, and user-space programs will receive 2710 notification of APM "events" (e.g. battery status change). 2711 2712 If you select "Y" here, you can disable actual use of the APM 2713 BIOS by passing the "apm=off" option to the kernel at boot time. 2714 2715 Note that the APM support is almost completely disabled for 2716 machines with more than one CPU. 2717 2718 In order to use APM, you will need supporting software. For location 2719 and more information, read <file:Documentation/power/apm-acpi.rst> 2720 and the Battery Powered Linux mini-HOWTO, available from 2721 <http://www.tldp.org/docs.html#howto>. 2722 2723 This driver does not spin down disk drives (see the hdparm(8) 2724 manpage ("man 8 hdparm") for that), and it doesn't turn off 2725 VESA-compliant "green" monitors. 2726 2727 Generally, if you don't have a battery in your machine, there isn't 2728 much point in using this driver and you should say N. If you get 2729 random kernel OOPSes or reboots that don't seem to be related to 2730 anything, try disabling/enabling this option (or disabling/enabling 2731 APM in your BIOS). 2732 2733 Some other things you should try when experiencing seemingly random, 2734 "weird" problems: 2735 2736 1) make sure that you have enough swap space and that it is 2737 enabled. 2738 2) pass the "idle=poll" option to the kernel 2739 3) pass the "floppy=nodma" option to the kernel 2740 4) pass the "mem=4M" option to the kernel (thereby disabling 2741 all but the first 4 MB of RAM) 2742 5) make sure that the CPU is not over clocked. 2743 6) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2744 7) disable the cache from your BIOS settings 2745 8) install a fan for the video card or exchange video RAM 2746 9) install a better fan for the CPU 2747 10) exchange RAM chips 2748 11) exchange the motherboard. 2749 2750 To compile this driver as a module, choose M here: the 2751 module will be called apm. 2752 2753if APM 2754 2755config APM_IGNORE_USER_SUSPEND 2756 bool "Ignore USER SUSPEND" 2757 help 2758 This option will ignore USER SUSPEND requests. On machines with a 2759 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2760 series notebooks, it is necessary to say Y because of a BIOS bug. 2761 2762config APM_DO_ENABLE 2763 bool "Enable PM at boot time" 2764 help 2765 Enable APM features at boot time. From page 36 of the APM BIOS 2766 specification: "When disabled, the APM BIOS does not automatically 2767 power manage devices, enter the Standby State, enter the Suspend 2768 State, or take power saving steps in response to CPU Idle calls." 2769 This driver will make CPU Idle calls when Linux is idle (unless this 2770 feature is turned off -- see "Do CPU IDLE calls", below). This 2771 should always save battery power, but more complicated APM features 2772 will be dependent on your BIOS implementation. You may need to turn 2773 this option off if your computer hangs at boot time when using APM 2774 support, or if it beeps continuously instead of suspending. Turn 2775 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2776 T400CDT. This is off by default since most machines do fine without 2777 this feature. 2778 2779config APM_CPU_IDLE 2780 depends on CPU_IDLE 2781 bool "Make CPU Idle calls when idle" 2782 help 2783 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2784 On some machines, this can activate improved power savings, such as 2785 a slowed CPU clock rate, when the machine is idle. These idle calls 2786 are made after the idle loop has run for some length of time (e.g., 2787 333 mS). On some machines, this will cause a hang at boot time or 2788 whenever the CPU becomes idle. (On machines with more than one CPU, 2789 this option does nothing.) 2790 2791config APM_DISPLAY_BLANK 2792 bool "Enable console blanking using APM" 2793 help 2794 Enable console blanking using the APM. Some laptops can use this to 2795 turn off the LCD backlight when the screen blanker of the Linux 2796 virtual console blanks the screen. Note that this is only used by 2797 the virtual console screen blanker, and won't turn off the backlight 2798 when using the X Window system. This also doesn't have anything to 2799 do with your VESA-compliant power-saving monitor. Further, this 2800 option doesn't work for all laptops -- it might not turn off your 2801 backlight at all, or it might print a lot of errors to the console, 2802 especially if you are using gpm. 2803 2804config APM_ALLOW_INTS 2805 bool "Allow interrupts during APM BIOS calls" 2806 help 2807 Normally we disable external interrupts while we are making calls to 2808 the APM BIOS as a measure to lessen the effects of a badly behaving 2809 BIOS implementation. The BIOS should reenable interrupts if it 2810 needs to. Unfortunately, some BIOSes do not -- especially those in 2811 many of the newer IBM Thinkpads. If you experience hangs when you 2812 suspend, try setting this to Y. Otherwise, say N. 2813 2814endif # APM 2815 2816source "drivers/cpufreq/Kconfig" 2817 2818source "drivers/cpuidle/Kconfig" 2819 2820source "drivers/idle/Kconfig" 2821 2822endmenu 2823 2824menu "Bus options (PCI etc.)" 2825 2826choice 2827 prompt "PCI access mode" 2828 depends on X86_32 && PCI 2829 default PCI_GOANY 2830 help 2831 On PCI systems, the BIOS can be used to detect the PCI devices and 2832 determine their configuration. However, some old PCI motherboards 2833 have BIOS bugs and may crash if this is done. Also, some embedded 2834 PCI-based systems don't have any BIOS at all. Linux can also try to 2835 detect the PCI hardware directly without using the BIOS. 2836 2837 With this option, you can specify how Linux should detect the 2838 PCI devices. If you choose "BIOS", the BIOS will be used, 2839 if you choose "Direct", the BIOS won't be used, and if you 2840 choose "MMConfig", then PCI Express MMCONFIG will be used. 2841 If you choose "Any", the kernel will try MMCONFIG, then the 2842 direct access method and falls back to the BIOS if that doesn't 2843 work. If unsure, go with the default, which is "Any". 2844 2845config PCI_GOBIOS 2846 bool "BIOS" 2847 2848config PCI_GOMMCONFIG 2849 bool "MMConfig" 2850 2851config PCI_GODIRECT 2852 bool "Direct" 2853 2854config PCI_GOOLPC 2855 bool "OLPC XO-1" 2856 depends on OLPC 2857 2858config PCI_GOANY 2859 bool "Any" 2860 2861endchoice 2862 2863config PCI_BIOS 2864 def_bool y 2865 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2866 2867# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2868config PCI_DIRECT 2869 def_bool y 2870 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2871 2872config PCI_MMCONFIG 2873 bool "Support mmconfig PCI config space access" if X86_64 2874 default y 2875 depends on PCI && (ACPI || JAILHOUSE_GUEST) 2876 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2877 help 2878 Add support for accessing the PCI configuration space as a memory 2879 mapped area. It is the recommended method if the system supports 2880 this (it must have PCI Express and ACPI for it to be available). 2881 2882 In the unlikely case that enabling this configuration option causes 2883 problems, the mechanism can be switched off with the 'pci=nommconf' 2884 command line parameter. 2885 2886 Say N only if you are sure that your platform does not support this 2887 access method or you have problems caused by it. 2888 2889 Say Y otherwise. 2890 2891config PCI_OLPC 2892 def_bool y 2893 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2894 2895config PCI_XEN 2896 def_bool y 2897 depends on PCI && XEN 2898 2899config MMCONF_FAM10H 2900 def_bool y 2901 depends on X86_64 && PCI_MMCONFIG && ACPI 2902 2903config PCI_CNB20LE_QUIRK 2904 bool "Read PCI host bridge windows from the CNB20LE chipset" if EXPERT 2905 depends on X86_32 && PCI 2906 help 2907 Read the PCI windows out of the CNB20LE host bridge. This allows 2908 PCI hotplug to work on systems with the CNB20LE chipset which do 2909 not have ACPI. 2910 2911 The ServerWorks (later Broadcom) CNB20LE was a chipset designed 2912 most probably only for Pentium III. 2913 2914 To find out if you have such a chipset, search for a PCI device with 2915 1166:0009 PCI IDs, for example by executing 2916 lspci -nn | grep '1166:0009' 2917 The code is inactive if there is none. 2918 2919 There's no public spec for this chipset, and this functionality 2920 is known to be incomplete. 2921 2922 You should say N unless you know you need this. 2923 2924config ISA_BUS 2925 bool "ISA bus support on modern systems" if EXPERT 2926 help 2927 Expose ISA bus device drivers and options available for selection and 2928 configuration. Enable this option if your target machine has an ISA 2929 bus. ISA is an older system, displaced by PCI and newer bus 2930 architectures -- if your target machine is modern, it probably does 2931 not have an ISA bus. 2932 2933 If unsure, say N. 2934 2935# x86_64 have no ISA slots, but can have ISA-style DMA. 2936config ISA_DMA_API 2937 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2938 default y 2939 help 2940 Enables ISA-style DMA support for devices requiring such controllers. 2941 If unsure, say Y. 2942 2943if X86_32 2944 2945config ISA 2946 bool "ISA support" 2947 help 2948 Find out whether you have ISA slots on your motherboard. ISA is the 2949 name of a bus system, i.e. the way the CPU talks to the other stuff 2950 inside your box. Other bus systems are PCI, EISA, MicroChannel 2951 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2952 newer boards don't support it. If you have ISA, say Y, otherwise N. 2953 2954config SCx200 2955 tristate "NatSemi SCx200 support" 2956 help 2957 This provides basic support for National Semiconductor's 2958 (now AMD's) Geode processors. The driver probes for the 2959 PCI-IDs of several on-chip devices, so its a good dependency 2960 for other scx200_* drivers. 2961 2962 If compiled as a module, the driver is named scx200. 2963 2964config SCx200HR_TIMER 2965 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2966 depends on SCx200 2967 default y 2968 help 2969 This driver provides a clocksource built upon the on-chip 2970 27MHz high-resolution timer. Its also a workaround for 2971 NSC Geode SC-1100's buggy TSC, which loses time when the 2972 processor goes idle (as is done by the scheduler). The 2973 other workaround is idle=poll boot option. 2974 2975config OLPC 2976 bool "One Laptop Per Child support" 2977 depends on !X86_PAE 2978 select GPIOLIB 2979 select OF 2980 select OF_PROMTREE 2981 select IRQ_DOMAIN 2982 select OLPC_EC 2983 help 2984 Add support for detecting the unique features of the OLPC 2985 XO hardware. 2986 2987config OLPC_XO1_PM 2988 bool "OLPC XO-1 Power Management" 2989 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2990 help 2991 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2992 2993config OLPC_XO1_RTC 2994 bool "OLPC XO-1 Real Time Clock" 2995 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2996 help 2997 Add support for the XO-1 real time clock, which can be used as a 2998 programmable wakeup source. 2999 3000config OLPC_XO1_SCI 3001 bool "OLPC XO-1 SCI extras" 3002 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 3003 depends on INPUT=y 3004 select POWER_SUPPLY 3005 help 3006 Add support for SCI-based features of the OLPC XO-1 laptop: 3007 - EC-driven system wakeups 3008 - Power button 3009 - Ebook switch 3010 - Lid switch 3011 - AC adapter status updates 3012 - Battery status updates 3013 3014config OLPC_XO15_SCI 3015 bool "OLPC XO-1.5 SCI extras" 3016 depends on OLPC && ACPI 3017 select POWER_SUPPLY 3018 help 3019 Add support for SCI-based features of the OLPC XO-1.5 laptop: 3020 - EC-driven system wakeups 3021 - AC adapter status updates 3022 - Battery status updates 3023 3024config GEODE_COMMON 3025 bool 3026 3027config ALIX 3028 bool "PCEngines ALIX System Support (LED setup)" 3029 select GPIOLIB 3030 select GEODE_COMMON 3031 help 3032 This option enables system support for the PCEngines ALIX. 3033 At present this just sets up LEDs for GPIO control on 3034 ALIX2/3/6 boards. However, other system specific setup should 3035 get added here. 3036 3037 Note: You must still enable the drivers for GPIO and LED support 3038 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 3039 3040 Note: You have to set alix.force=1 for boards with Award BIOS. 3041 3042config NET5501 3043 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 3044 select GPIOLIB 3045 select GEODE_COMMON 3046 help 3047 This option enables system support for the Soekris Engineering net5501. 3048 3049config GEOS 3050 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 3051 select GPIOLIB 3052 select GEODE_COMMON 3053 depends on DMI 3054 help 3055 This option enables system support for the Traverse Technologies GEOS. 3056 3057config TS5500 3058 bool "Technologic Systems TS-5500 platform support" 3059 depends on MELAN 3060 select CHECK_SIGNATURE 3061 select NEW_LEDS 3062 select LEDS_CLASS 3063 help 3064 This option enables system support for the Technologic Systems TS-5500. 3065 3066endif # X86_32 3067 3068config AMD_NB 3069 def_bool y 3070 depends on AMD_NODE 3071 3072config AMD_NODE 3073 def_bool y 3074 depends on CPU_SUP_AMD && PCI 3075 3076endmenu 3077 3078menu "Binary Emulations" 3079 3080config IA32_EMULATION 3081 bool "IA32 Emulation" 3082 depends on X86_64 3083 select ARCH_WANT_OLD_COMPAT_IPC 3084 select BINFMT_ELF 3085 select COMPAT_OLD_SIGACTION 3086 help 3087 Include code to run legacy 32-bit programs under a 3088 64-bit kernel. You should likely turn this on, unless you're 3089 100% sure that you don't have any 32-bit programs left. 3090 3091config IA32_EMULATION_DEFAULT_DISABLED 3092 bool "IA32 emulation disabled by default" 3093 default n 3094 depends on IA32_EMULATION 3095 help 3096 Make IA32 emulation disabled by default. This prevents loading 32-bit 3097 processes and access to 32-bit syscalls. If unsure, leave it to its 3098 default value. 3099 3100config X86_X32_ABI 3101 bool "x32 ABI for 64-bit mode" 3102 depends on X86_64 3103 # llvm-objcopy does not convert x86_64 .note.gnu.property or 3104 # compressed debug sections to x86_x32 properly: 3105 # https://github.com/ClangBuiltLinux/linux/issues/514 3106 # https://github.com/ClangBuiltLinux/linux/issues/1141 3107 depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm) 3108 help 3109 Include code to run binaries for the x32 native 32-bit ABI 3110 for 64-bit processors. An x32 process gets access to the 3111 full 64-bit register file and wide data path while leaving 3112 pointers at 32 bits for smaller memory footprint. 3113 3114config COMPAT_32 3115 def_bool y 3116 depends on IA32_EMULATION || X86_32 3117 select HAVE_UID16 3118 select OLD_SIGSUSPEND3 3119 3120config COMPAT 3121 def_bool y 3122 depends on IA32_EMULATION || X86_X32_ABI 3123 3124config COMPAT_FOR_U64_ALIGNMENT 3125 def_bool y 3126 depends on COMPAT 3127 3128endmenu 3129 3130config HAVE_ATOMIC_IOMAP 3131 def_bool y 3132 depends on X86_32 3133 3134source "arch/x86/kvm/Kconfig" 3135 3136source "arch/x86/Kconfig.cpufeatures" 3137 3138source "arch/x86/Kconfig.assembler" 3139