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_HAS_PMD_SOFTLEAVES 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_DELAY_TIMER 84 select ARCH_HAS_DEVMEM_IS_ALLOWED 85 select ARCH_HAS_DMA_OPS if GART_IOMMU || XEN 86 select ARCH_HAS_EARLY_DEBUG if KGDB 87 select ARCH_HAS_ELF_RANDOMIZE 88 select ARCH_HAS_EXECMEM_ROX if X86_64 && STRICT_MODULE_RWX 89 select ARCH_HAS_FAST_MULTIPLIER 90 select ARCH_HAS_FORTIFY_SOURCE 91 select ARCH_HAS_GCOV_PROFILE_ALL 92 select ARCH_HAS_KCOV if X86_64 93 select ARCH_HAS_KERNEL_FPU_SUPPORT 94 select ARCH_HAS_MEM_ENCRYPT 95 select ARCH_HAS_MEMBARRIER_SYNC_CORE 96 select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS 97 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 98 select ARCH_HAS_PMEM_API if X86_64 99 select ARCH_HAS_PREEMPT_LAZY 100 select ARCH_HAS_PTDUMP 101 select ARCH_HAS_PTE_SPECIAL 102 select ARCH_HAS_HW_PTE_YOUNG 103 select ARCH_HAS_NONLEAF_PMD_YOUNG if PGTABLE_LEVELS > 2 104 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 105 select ARCH_HAS_COPY_MC if X86_64 106 select ARCH_HAS_SET_MEMORY 107 select ARCH_HAS_SET_DIRECT_MAP 108 select ARCH_HAS_STRICT_KERNEL_RWX 109 select ARCH_HAS_STRICT_MODULE_RWX 110 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 111 select ARCH_HAS_SYSCALL_WRAPPER 112 select ARCH_HAS_UBSAN 113 select ARCH_HAS_DEBUG_WX 114 select ARCH_HAS_ZONE_DMA_SET if EXPERT 115 select ARCH_HAVE_NMI_SAFE_CMPXCHG 116 select ARCH_HAVE_EXTRA_ELF_NOTES 117 select ARCH_MEMORY_ORDER_TSO 118 select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 119 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 120 select ARCH_MIGHT_HAVE_PC_PARPORT 121 select ARCH_MIGHT_HAVE_PC_SERIO 122 select ARCH_STACKWALK 123 select ARCH_SUPPORTS_ACPI 124 select ARCH_SUPPORTS_ATOMIC_RMW 125 select ARCH_SUPPORTS_DEBUG_PAGEALLOC 126 select ARCH_SUPPORTS_HUGETLBFS 127 select ARCH_SUPPORTS_PAGE_TABLE_CHECK if X86_64 128 select ARCH_HAS_PTE_PROTNONE if X86_64 129 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 130 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 131 select ARCH_SUPPORTS_CFI if X86_64 132 select ARCH_SUPPORTS_CMDLINE_FROM_BOOTCONFIG 133 select ARCH_USES_CFI_TRAPS if X86_64 && CFI 134 select ARCH_SUPPORTS_LTO_CLANG 135 select ARCH_SUPPORTS_LTO_CLANG_THIN 136 select ARCH_SUPPORTS_RT 137 select ARCH_USE_BUILTIN_BSWAP 138 select ARCH_USE_CMPXCHG_LOCKREF 139 select ARCH_USE_MEMTEST 140 select ARCH_USE_QUEUED_RWLOCKS 141 select ARCH_USE_QUEUED_SPINLOCKS 142 select ARCH_USE_SYM_ANNOTATIONS 143 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 144 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 145 select ARCH_WANTS_CLOCKSOURCE_READ_INLINE if X86_64 146 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 147 select ARCH_WANTS_NO_INSTR 148 select ARCH_WANT_GENERAL_HUGETLB 149 select ARCH_WANT_HUGE_PMD_SHARE if X86_64 150 select ARCH_WANT_LD_ORPHAN_WARN 151 select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP if X86_64 152 select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP if X86_64 153 select ARCH_WANT_HUGETLB_VMEMMAP_PREINIT if X86_64 154 select ARCH_WANTS_THP_SWAP if X86_64 155 select ARCH_HAS_PARANOID_L1D_FLUSH 156 select ARCH_WANT_IRQS_OFF_ACTIVATE_MM 157 select BUILDTIME_TABLE_SORT 158 select CLKEVT_I8253 159 select CLOCKSOURCE_WATCHDOG 160 # Word-size accesses may read uninitialized data past the trailing \0 161 # in strings and cause false KMSAN reports. 162 select DCACHE_WORD_ACCESS if !KMSAN 163 select DYNAMIC_SIGFRAME 164 select EDAC_ATOMIC_SCRUB 165 select EDAC_SUPPORT 166 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 167 select GENERIC_CLOCKEVENTS_BROADCAST_IDLE if GENERIC_CLOCKEVENTS_BROADCAST 168 select GENERIC_CLOCKEVENTS_COUPLED_INLINE if X86_64 169 select GENERIC_CLOCKEVENTS_MIN_ADJUST 170 select GENERIC_CMOS_UPDATE 171 select GENERIC_CPU_AUTOPROBE 172 select GENERIC_CPU_DEVICES 173 select GENERIC_CPU_VULNERABILITIES 174 select GENERIC_EARLY_IOREMAP 175 select GENERIC_ENTRY 176 select GENERIC_IOMAP 177 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 178 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 179 select GENERIC_IRQ_MIGRATION if SMP 180 select GENERIC_IRQ_PROBE 181 select GENERIC_IRQ_RESERVATION_MODE 182 select GENERIC_IRQ_SHOW 183 select GENERIC_PENDING_IRQ if SMP 184 select GENERIC_SMP_IDLE_THREAD 185 select GENERIC_GETTIMEOFDAY 186 select GENERIC_VDSO_OVERFLOW_PROTECT 187 select GUP_GET_PXX_LOW_HIGH if X86_PAE 188 select HARDIRQS_SW_RESEND 189 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 190 select HAS_IOPORT 191 select HAVE_ACPI_APEI if ACPI 192 select HAVE_ACPI_APEI_NMI if ACPI 193 select HAVE_ALIGNED_STRUCT_PAGE 194 select HAVE_ARCH_AUDITSYSCALL 195 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 196 select HAVE_ARCH_HUGE_VMALLOC if X86_64 197 select HAVE_ARCH_JUMP_LABEL 198 select HAVE_ARCH_JUMP_LABEL_RELATIVE 199 select HAVE_ARCH_KASAN if X86_64 200 select HAVE_ARCH_KASAN_VMALLOC if X86_64 201 select HAVE_ARCH_KFENCE 202 select HAVE_ARCH_KMSAN if X86_64 203 select HAVE_ARCH_KGDB 204 select HAVE_ARCH_KSTACK_ERASE 205 select HAVE_ARCH_MMAP_RND_BITS if MMU 206 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 207 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 208 select HAVE_ARCH_PREL32_RELOCATIONS 209 select HAVE_ARCH_SECCOMP_FILTER 210 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 211 select HAVE_ARCH_TRACEHOOK 212 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 213 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 214 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 215 select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 216 select HAVE_ARCH_VMAP_STACK if X86_64 217 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 218 select HAVE_ARCH_WITHIN_STACK_FRAMES 219 select HAVE_ASM_MODVERSIONS 220 select HAVE_CMPXCHG_DOUBLE 221 select HAVE_CMPXCHG_LOCAL 222 select HAVE_CONTEXT_TRACKING_USER if X86_64 223 select HAVE_CONTEXT_TRACKING_USER_OFFSTACK if HAVE_CONTEXT_TRACKING_USER 224 select HAVE_C_RECORDMCOUNT 225 select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL 226 select HAVE_OBJTOOL_NOP_MCOUNT if HAVE_OBJTOOL_MCOUNT 227 select HAVE_BUILDTIME_MCOUNT_SORT 228 select HAVE_DEBUG_KMEMLEAK 229 select HAVE_DMA_CONTIGUOUS 230 select HAVE_DYNAMIC_FTRACE 231 select HAVE_DYNAMIC_FTRACE_WITH_REGS 232 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 233 select HAVE_FTRACE_REGS_HAVING_PT_REGS if X86_64 234 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 235 select HAVE_DYNAMIC_FTRACE_WITH_JMP if X86_64 236 select HAVE_SAMPLE_FTRACE_DIRECT if X86_64 237 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64 238 select HAVE_EBPF_JIT 239 select HAVE_EFFICIENT_UNALIGNED_ACCESS 240 select HAVE_EISA if X86_32 241 select HAVE_EXIT_THREAD 242 select HAVE_FUTEX_ROBUST_UNLOCK 243 select HAVE_GENERIC_TIF_BITS 244 select HAVE_GUP_FAST 245 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 246 select HAVE_FTRACE_GRAPH_FUNC if HAVE_FUNCTION_GRAPH_TRACER 247 select HAVE_FUNCTION_GRAPH_FREGS if HAVE_FUNCTION_GRAPH_TRACER 248 select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) 249 select HAVE_FUNCTION_TRACER 250 select HAVE_GCC_PLUGINS 251 select HAVE_HW_BREAKPOINT 252 select HAVE_IOREMAP_PROT 253 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 254 select HAVE_IRQ_TIME_ACCOUNTING 255 select HAVE_JUMP_LABEL_HACK if HAVE_OBJTOOL 256 select HAVE_KERNEL_BZIP2 257 select HAVE_KERNEL_GZIP 258 select HAVE_KERNEL_LZ4 259 select HAVE_KERNEL_LZMA 260 select HAVE_KERNEL_LZO 261 select HAVE_KERNEL_XZ 262 select HAVE_KERNEL_ZSTD 263 select HAVE_KPROBES 264 select HAVE_KPROBES_ON_FTRACE 265 select HAVE_FUNCTION_ERROR_INJECTION 266 select HAVE_KRETPROBES 267 select HAVE_RETHOOK 268 select HAVE_KLP_BUILD if X86_64 269 select HAVE_LIVEPATCH if X86_64 270 select HAVE_MIXED_BREAKPOINTS_REGS 271 select HAVE_MOD_ARCH_SPECIFIC 272 select HAVE_MOVE_PMD 273 select HAVE_MOVE_PUD 274 select HAVE_NOINSTR_HACK if HAVE_OBJTOOL 275 select HAVE_NMI 276 select HAVE_NOINSTR_VALIDATION if HAVE_OBJTOOL 277 select HAVE_OBJTOOL if X86_64 278 select HAVE_OPTPROBES 279 select HAVE_PAGE_SIZE_4KB 280 select HAVE_PCSPKR_PLATFORM 281 select HAVE_PERF_EVENTS 282 select HAVE_PERF_EVENTS_NMI 283 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 284 select HAVE_PCI 285 select HAVE_PERF_REGS 286 select HAVE_PERF_USER_STACK_DUMP 287 select ASYNC_KERNEL_PGTABLE_FREE if IOMMU_SVA 288 select MMU_GATHER_RCU_TABLE_FREE 289 select MMU_GATHER_MERGE_VMAS 290 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 291 select HAVE_REGS_AND_STACK_ACCESS_API 292 select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC || STACK_VALIDATION 293 select HAVE_FUNCTION_ARG_ACCESS_API 294 select HAVE_SETUP_PER_CPU_AREA 295 select HAVE_SOFTIRQ_ON_OWN_STACK 296 select HAVE_STACKPROTECTOR 297 select HAVE_STACK_VALIDATION if HAVE_OBJTOOL 298 select HAVE_STATIC_CALL 299 select HAVE_STATIC_CALL_INLINE if HAVE_OBJTOOL 300 select HAVE_PREEMPT_DYNAMIC_CALL 301 select HAVE_RSEQ 302 select HAVE_RUST if X86_64 303 select HAVE_SYSCALL_TRACEPOINTS 304 select HAVE_UACCESS_VALIDATION if HAVE_OBJTOOL 305 select HAVE_UNSTABLE_SCHED_CLOCK 306 select HAVE_UNWIND_USER_FP if X86_64 307 select HAVE_USER_RETURN_NOTIFIER 308 select VDSO_GETRANDOM if X86_64 309 select HOTPLUG_PARALLEL if SMP && X86_64 310 select HOTPLUG_SMT if SMP 311 select HOTPLUG_SPLIT_STARTUP if SMP && X86_32 312 select IRQ_FORCED_THREADING 313 select LOCK_MM_AND_FIND_VMA 314 select NEED_PER_CPU_EMBED_FIRST_CHUNK 315 select NEED_PER_CPU_PAGE_FIRST_CHUNK 316 select NEED_SG_DMA_LENGTH 317 select NUMA_MEMBLKS if NUMA 318 select PCI_DOMAINS if PCI 319 select PCI_LOCKLESS_CONFIG if PCI 320 select PERF_EVENTS 321 select RTC_LIB 322 select RTC_MC146818_LIB 323 select SPARSE_IRQ 324 select SYSCTL_EXCEPTION_TRACE 325 select THREAD_INFO_IN_TASK 326 select TRACE_IRQFLAGS_SUPPORT 327 select TRACE_IRQFLAGS_NMI_SUPPORT 328 select USER_STACKTRACE_SUPPORT 329 select HAVE_ARCH_KCSAN if X86_64 330 select PROC_PID_ARCH_STATUS if PROC_FS 331 select HAS_SEPARATE_PREEMPT_RESCHED_BITS if X86_64 && PREEMPT_COUNT 332 select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX 333 select FUNCTION_ALIGNMENT_16B if X86_64 || X86_ALIGNMENT_16 334 select FUNCTION_ALIGNMENT_4B 335 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 336 select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 337 select ARCH_SUPPORTS_SCHED_SMT if SMP 338 select SCHED_SMT if SMP 339 select ARCH_SUPPORTS_SCHED_CLUSTER if SMP 340 select ARCH_SUPPORTS_SCHED_MC if SMP 341 select ARCH_SUPPORTS_SYSCALL_USER_DISPATCH 342 select HAVE_SINGLE_FTRACE_DIRECT_OPS if X86_64 && DYNAMIC_FTRACE_WITH_DIRECT_CALLS 343 344config INSTRUCTION_DECODER 345 def_bool y 346 depends on KPROBES || PERF_EVENTS || UPROBES 347 348config OUTPUT_FORMAT 349 string 350 default "elf32-i386" if X86_32 351 default "elf64-x86-64" if X86_64 352 353config LOCKDEP_SUPPORT 354 def_bool y 355 356config STACKTRACE_SUPPORT 357 def_bool y 358 359config MMU 360 def_bool y 361 362config ARCH_MMAP_RND_BITS_MIN 363 default 28 if 64BIT 364 default 8 365 366config ARCH_MMAP_RND_BITS_MAX 367 default 32 if 64BIT 368 default 16 369 370config ARCH_MMAP_RND_COMPAT_BITS_MIN 371 default 8 372 373config ARCH_MMAP_RND_COMPAT_BITS_MAX 374 default 16 375 376config SBUS 377 bool 378 379config GENERIC_ISA_DMA 380 def_bool y 381 depends on ISA_DMA_API 382 383config GENERIC_CSUM 384 bool 385 default y if KMSAN || KASAN 386 387config GENERIC_BUG 388 def_bool y 389 depends on BUG 390 select GENERIC_BUG_RELATIVE_POINTERS 391 392config GENERIC_BUG_RELATIVE_POINTERS 393 bool 394 395config ARCH_MAY_HAVE_PC_FDC 396 def_bool y 397 depends on ISA_DMA_API 398 399config GENERIC_CALIBRATE_DELAY 400 def_bool y 401 402config ARCH_HAS_CPU_RELAX 403 def_bool y 404 405config ARCH_HIBERNATION_POSSIBLE 406 def_bool y 407 408config ARCH_SUSPEND_POSSIBLE 409 def_bool y 410 411config AUDIT_ARCH 412 def_bool y if X86_64 413 414config KASAN_SHADOW_OFFSET 415 hex 416 depends on KASAN 417 default 0xdffffc0000000000 418 419config HAVE_INTEL_TXT 420 def_bool y 421 depends on INTEL_IOMMU && ACPI 422 423config ARCH_SUPPORTS_UPROBES 424 def_bool y 425 426config FIX_EARLYCON_MEM 427 def_bool y 428 429config DYNAMIC_PHYSICAL_MASK 430 bool 431 432config PGTABLE_LEVELS 433 int 434 default 5 if X86_64 435 default 3 if X86_PAE 436 default 2 437 438menu "Processor type and features" 439 440config SMP 441 bool "Symmetric multi-processing support" 442 help 443 This enables support for systems with more than one CPU. If you have 444 a system with only one CPU, say N. If you have a system with more 445 than one CPU, say Y. 446 447 If you say N here, the kernel will run on uni- and multiprocessor 448 machines, but will use only one CPU of a multiprocessor machine. If 449 you say Y here, the kernel will run on many, but not all, 450 uniprocessor machines. On a uniprocessor machine, the kernel 451 will run faster if you say N here. 452 453 People using multiprocessor machines who say Y here should also say 454 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 455 Management" code will be disabled if you say Y here. 456 457 See also <file:Documentation/arch/x86/i386/IO-APIC.rst>, 458 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 459 <http://www.tldp.org/docs.html#howto>. 460 461 If you don't know what to do here, say N. 462 463config X86_X2APIC 464 bool "x2APIC interrupt controller architecture support" 465 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 466 default y 467 help 468 x2APIC is an interrupt controller architecture, a component of which 469 (the local APIC) is present in the CPU. It allows faster access to 470 the local APIC and supports a larger number of CPUs in the system 471 than the predecessors. 472 473 x2APIC was introduced in Intel CPUs around 2008 and in AMD EPYC CPUs 474 in 2019, but it can be disabled by the BIOS. It is also frequently 475 emulated in virtual machines, even when the host CPU does not support 476 it. Support in the CPU can be checked by executing 477 grep x2apic /proc/cpuinfo 478 479 If this configuration option is disabled, the kernel will boot with 480 very reduced functionality and performance on some platforms that 481 have x2APIC enabled. On the other hand, on hardware that does not 482 support x2APIC, a kernel with this option enabled will just fallback 483 to older APIC implementations. 484 485 If in doubt, say Y. 486 487config AMD_SECURE_AVIC 488 bool "AMD Secure AVIC" 489 depends on AMD_MEM_ENCRYPT && X86_X2APIC 490 help 491 Enable this to get AMD Secure AVIC support on guests that have this feature. 492 493 AMD Secure AVIC provides hardware acceleration for performance sensitive 494 APIC accesses and support for managing guest owned APIC state for SEV-SNP 495 guests. Secure AVIC does not support xAPIC mode. It has functional 496 dependency on x2apic being enabled in the guest. 497 498 If you don't know what to do here, say N. 499 500config X86_POSTED_MSI 501 bool "Enable MSI and MSI-x delivery by posted interrupts" 502 depends on X86_64 && IRQ_REMAP 503 help 504 This enables MSIs that are under interrupt remapping to be delivered as 505 posted interrupts to the host kernel. Interrupt throughput can 506 potentially be improved by coalescing CPU notifications during high 507 frequency bursts. 508 509 If you don't know what to do here, say N. 510 511config X86_MPPARSE 512 bool "Enable MPS table" if ACPI 513 default y 514 depends on X86_LOCAL_APIC 515 help 516 For old smp systems that do not have proper acpi support. Newer systems 517 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 518 519config X86_CPU_RESCTRL 520 bool "x86 CPU resource control support" 521 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 522 depends on MISC_FILESYSTEMS 523 select ARCH_HAS_CPU_RESCTRL 524 select RESCTRL_FS 525 select RESCTRL_FS_PSEUDO_LOCK 526 help 527 Enable x86 CPU resource control support. 528 529 Provide support for the allocation and monitoring of system resources 530 usage by the CPU. 531 532 Intel calls this Intel Resource Director Technology 533 (Intel(R) RDT). More information about RDT can be found in the 534 Intel x86 Architecture Software Developer Manual. 535 536 AMD calls this AMD Platform Quality of Service (AMD QoS). 537 More information about AMD QoS can be found in the AMD64 Technology 538 Platform Quality of Service Extensions manual. 539 540 Say N if unsure. 541 542config X86_CPU_RESCTRL_INTEL_AET 543 bool "Intel Application Energy Telemetry" 544 depends on X86_64 && X86_CPU_RESCTRL && CPU_SUP_INTEL && INTEL_PMT_TELEMETRY=y && INTEL_TPMI=y 545 help 546 Enable per-RMID telemetry events in resctrl. 547 548 Intel feature that collects per-RMID execution data 549 about energy consumption, measure of frequency independent 550 activity and other performance metrics. Data is aggregated 551 per package. 552 553 Say N if unsure. 554 555config X86_FRED 556 bool "Flexible Return and Event Delivery" 557 depends on X86_64 558 help 559 When enabled, use Flexible Return and Event Delivery 560 instead of the legacy SYSCALL/SYSENTER/IDT architecture for 561 ring transitions and exception/interrupt handling if the 562 system supports it. 563 564config X86_EXTENDED_PLATFORM 565 bool "Support for extended (non-PC) x86 platforms" 566 default y 567 help 568 If you disable this option then the kernel will only support 569 standard PC platforms. (which covers the vast majority of 570 systems out there.) 571 572 If you enable this option then you'll be able to select support 573 for the following non-PC x86 platforms, depending on the value of 574 CONFIG_64BIT. 575 576 32-bit platforms (CONFIG_64BIT=n): 577 Goldfish (mostly Android emulator) 578 Intel CE media processor (CE4100) SoC 579 Intel Quark 580 RDC R-321x SoC 581 582 64-bit platforms (CONFIG_64BIT=y): 583 Numascale NumaChip 584 ScaleMP vSMP 585 SGI Ultraviolet 586 Merrifield/Moorefield MID devices 587 Goldfish (mostly Android emulator) 588 589 If you have one of these systems, or if you want to build a 590 generic distribution kernel, say Y here - otherwise say N. 591 592# This is an alphabetically sorted list of 64 bit extended platforms 593# Please maintain the alphabetic order if and when there are additions 594config X86_NUMACHIP 595 bool "Numascale NumaChip" 596 depends on X86_64 597 depends on X86_EXTENDED_PLATFORM 598 depends on NUMA 599 depends on SMP 600 depends on X86_X2APIC 601 depends on PCI_MMCONFIG 602 help 603 Adds support for Numascale NumaChip large-SMP systems. Needed to 604 enable more than ~168 cores. 605 If you don't have one of these, you should say N here. 606 607config X86_VSMP 608 bool "ScaleMP vSMP" 609 select HYPERVISOR_GUEST 610 select PARAVIRT 611 depends on X86_64 && PCI 612 depends on X86_EXTENDED_PLATFORM 613 depends on SMP 614 help 615 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 616 supposed to run on these EM64T-based machines. Only choose this option 617 if you have one of these machines. 618 619config X86_UV 620 bool "SGI Ultraviolet" 621 depends on X86_64 622 depends on X86_EXTENDED_PLATFORM 623 depends on NUMA 624 depends on EFI 625 depends on KEXEC_CORE 626 depends on X86_X2APIC 627 depends on PCI 628 help 629 This option is needed in order to support SGI Ultraviolet systems. 630 If you don't have one of these, you should say N here. 631 632config X86_INTEL_MID 633 bool "Intel Z34xx/Z35xx MID platform support" 634 depends on X86_EXTENDED_PLATFORM 635 depends on X86_PLATFORM_DEVICES 636 depends on PCI 637 depends on X86_64 || (EXPERT && PCI_GOANY) 638 depends on X86_IO_APIC 639 select I2C 640 select DW_APB_TIMER 641 select INTEL_SCU_PCI 642 help 643 Select to build a kernel capable of supporting 64-bit Intel MID 644 (Mobile Internet Device) platform systems which do not have 645 the PCI legacy interfaces. 646 647 The only supported devices are the 22nm Merrified (Z34xx) 648 and Moorefield (Z35xx) SoC used in the Intel Edison board and 649 a small number of Android devices such as the Asus Zenfone 2, 650 Asus FonePad 8 and Dell Venue 7. 651 652 If you are building for a PC class system or non-MID tablet 653 SoCs like Bay Trail (Z36xx/Z37xx), say N here. 654 655 Intel MID platforms are based on an Intel processor and chipset which 656 consume less power than most of the x86 derivatives. 657 658config X86_GOLDFISH 659 bool "Goldfish (Virtual Platform)" 660 depends on X86_EXTENDED_PLATFORM 661 help 662 Enable support for the Goldfish virtual platform used primarily 663 for Android development. Unless you are building for the Android 664 Goldfish emulator say N here. 665 666# Following is an alphabetically sorted list of 32 bit extended platforms 667# Please maintain the alphabetic order if and when there are additions 668 669config X86_INTEL_CE 670 bool "CE4100 TV platform" 671 depends on PCI 672 depends on PCI_GODIRECT 673 depends on X86_IO_APIC 674 depends on X86_32 675 depends on X86_EXTENDED_PLATFORM 676 select X86_REBOOTFIXUPS 677 select OF 678 select OF_EARLY_FLATTREE 679 help 680 Select for the Intel CE media processor (CE4100) SOC. 681 This option compiles in support for the CE4100 SOC for settop 682 boxes and media devices. 683 684config X86_INTEL_QUARK 685 bool "Intel Quark platform support" 686 depends on X86_32 687 depends on X86_EXTENDED_PLATFORM 688 depends on X86_PLATFORM_DEVICES 689 depends on PCI 690 depends on PCI_GOANY 691 depends on X86_IO_APIC 692 select IOSF_MBI 693 select INTEL_IMR 694 select COMMON_CLK 695 help 696 Select to include support for Quark X1000 SoC. 697 Say Y here if you have a Quark based system such as the Arduino 698 compatible Intel Galileo. 699 700config X86_INTEL_LPSS 701 bool "Intel Low Power Subsystem Support" 702 depends on X86 && ACPI && PCI 703 select COMMON_CLK 704 select PINCTRL 705 select IOSF_MBI 706 help 707 Select to build support for Intel Low Power Subsystem such as 708 found on Intel Lynxpoint PCH. Selecting this option enables 709 things like clock tree (common clock framework) and pincontrol 710 which are needed by the LPSS peripheral drivers. 711 712config X86_AMD_PLATFORM_DEVICE 713 bool "AMD ACPI2Platform devices support" 714 depends on ACPI 715 select COMMON_CLK 716 select PINCTRL 717 help 718 Select to interpret AMD specific ACPI device to platform device 719 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 720 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 721 implemented under PINCTRL subsystem. 722 723config IOSF_MBI 724 tristate "Intel SoC IOSF Sideband support for SoC platforms" 725 depends on PCI 726 help 727 This option enables sideband register access support for Intel SoC 728 platforms. On these platforms the IOSF sideband is used in lieu of 729 MSR's for some register accesses, mostly but not limited to thermal 730 and power. Drivers may query the availability of this device to 731 determine if they need the sideband in order to work on these 732 platforms. The sideband is available on the following SoC products. 733 This list is not meant to be exclusive. 734 - BayTrail 735 - Braswell 736 - Quark 737 738 You should say Y if you are running a kernel on one of these SoC's. 739 740config IOSF_MBI_DEBUG 741 bool "Enable IOSF sideband access through debugfs" 742 depends on IOSF_MBI && DEBUG_FS 743 help 744 Select this option to expose the IOSF sideband access registers (MCR, 745 MDR, MCRX) through debugfs to write and read register information from 746 different units on the SoC. This is most useful for obtaining device 747 state information for debug and analysis. As this is a general access 748 mechanism, users of this option would have specific knowledge of the 749 device they want to access. 750 751 If you don't require the option or are in doubt, say N. 752 753config X86_SUPPORTS_MEMORY_FAILURE 754 def_bool y 755 # MCE code calls memory_failure(): 756 depends on X86_MCE 757 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 758 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 759 depends on X86_64 || !SPARSEMEM 760 select ARCH_SUPPORTS_MEMORY_FAILURE 761 762config X86_32_IRIS 763 tristate "Eurobraille/Iris poweroff module" 764 depends on X86_32 765 help 766 The Iris machines from EuroBraille do not have APM or ACPI support 767 to shut themselves down properly. A special I/O sequence is 768 needed to do so, which is what this module does at 769 kernel shutdown. 770 771 This is only for Iris machines from EuroBraille. 772 773 If unused, say N. 774 775config SCHED_OMIT_FRAME_POINTER 776 def_bool y 777 prompt "Single-depth WCHAN output" 778 depends on X86 779 help 780 Calculate simpler /proc/<PID>/wchan values. If this option 781 is disabled then wchan values will recurse back to the 782 caller function. This provides more accurate wchan values, 783 at the expense of slightly more scheduling overhead. 784 785 If in doubt, say "Y". 786 787menuconfig HYPERVISOR_GUEST 788 bool "Linux guest support" 789 help 790 Say Y here to enable options for running Linux under various hyper- 791 visors. This option enables basic hypervisor detection and platform 792 setup. 793 794 If you say N, all options in this submenu will be skipped and 795 disabled, and Linux guest support won't be built in. 796 797if HYPERVISOR_GUEST 798 799config PARAVIRT 800 bool "Enable paravirtualization code" 801 depends on HAVE_STATIC_CALL 802 select HAVE_PV_STEAL_CLOCK_GEN 803 help 804 This changes the kernel so it can modify itself when it is run 805 under a hypervisor, potentially improving performance significantly 806 over full virtualization. However, when run without a hypervisor 807 the kernel is theoretically slower and slightly larger. 808 809config PARAVIRT_XXL 810 bool 811 depends on X86_64 812 select ARCH_HAS_LAZY_MMU_MODE 813 814config PARAVIRT_SPINLOCKS 815 bool "Paravirtualization layer for spinlocks" 816 depends on PARAVIRT && SMP 817 help 818 Paravirtualized spinlocks allow a pvops backend to replace the 819 spinlock implementation with something virtualization-friendly 820 (for example, block the virtual CPU rather than spinning). 821 822 It has a minimal impact on native kernels and gives a nice performance 823 benefit on paravirtualized KVM / Xen kernels. 824 825 If you are unsure how to answer this question, answer Y. 826 827config X86_HV_CALLBACK_VECTOR 828 def_bool n 829 830source "arch/x86/xen/Kconfig" 831 832config KVM_GUEST 833 bool "KVM Guest support (including kvmclock)" 834 depends on PARAVIRT 835 select PARAVIRT_CLOCK 836 select ARCH_CPUIDLE_HALTPOLL 837 select X86_HV_CALLBACK_VECTOR 838 default y 839 help 840 This option enables various optimizations for running under the KVM 841 hypervisor. It includes a paravirtualized clock, so that instead 842 of relying on a PIT (or probably other) emulation by the 843 underlying device model, the host provides the guest with 844 timing infrastructure such as time of day, and system time 845 846config ARCH_CPUIDLE_HALTPOLL 847 def_bool n 848 prompt "Disable host haltpoll when loading haltpoll driver" 849 help 850 If virtualized under KVM, disable host haltpoll. 851 852config PVH 853 bool "Support for running PVH guests" 854 help 855 This option enables the PVH entry point for guest virtual machines 856 as specified in the x86/HVM direct boot ABI. 857 858config PARAVIRT_TIME_ACCOUNTING 859 bool "Paravirtual steal time accounting" 860 depends on PARAVIRT 861 help 862 Select this option to enable fine granularity task steal time 863 accounting. Time spent executing other tasks in parallel with 864 the current vCPU is discounted from the vCPU power. To account for 865 that, there can be a small performance impact. 866 867 If in doubt, say N here. 868 869config PARAVIRT_CLOCK 870 bool 871 872config JAILHOUSE_GUEST 873 bool "Jailhouse non-root cell support" 874 depends on X86_64 && PCI 875 select X86_PM_TIMER 876 help 877 This option allows to run Linux as guest in a Jailhouse non-root 878 cell. You can leave this option disabled if you only want to start 879 Jailhouse and run Linux afterwards in the root cell. 880 881config ACRN_GUEST 882 bool "ACRN Guest support" 883 depends on X86_64 884 select X86_HV_CALLBACK_VECTOR 885 help 886 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 887 a flexible, lightweight reference open-source hypervisor, built with 888 real-time and safety-criticality in mind. It is built for embedded 889 IOT with small footprint and real-time features. More details can be 890 found in https://projectacrn.org/. 891 892config BHYVE_GUEST 893 bool "Bhyve (BSD Hypervisor) Guest support" 894 depends on X86_64 895 help 896 This option allows to run Linux to recognise when it is running as a 897 guest in the Bhyve hypervisor, and to support more than 255 vCPUs when 898 when doing so. More details about Bhyve can be found at https://bhyve.org 899 and https://wiki.freebsd.org/bhyve/. 900 901config INTEL_TDX_GUEST 902 bool "Intel TDX (Trust Domain Extensions) - Guest Support" 903 depends on X86_64 && CPU_SUP_INTEL 904 depends on X86_X2APIC 905 depends on EFI_STUB 906 depends on PARAVIRT 907 select ARCH_HAS_CC_PLATFORM 908 select X86_MEM_ENCRYPT 909 select X86_MCE 910 select UNACCEPTED_MEMORY 911 help 912 Support running as a guest under Intel TDX. Without this support, 913 the guest kernel can not boot or run under TDX. 914 TDX includes memory encryption and integrity capabilities 915 which protect the confidentiality and integrity of guest 916 memory contents and CPU state. TDX guests are protected from 917 some attacks from the VMM. 918 919endif # HYPERVISOR_GUEST 920 921source "arch/x86/Kconfig.cpu" 922 923config HPET_TIMER 924 def_bool X86_64 925 prompt "HPET Timer Support" if X86_32 926 help 927 Use the IA-PC HPET (High Precision Event Timer) to manage 928 time in preference to the PIT and RTC, if a HPET is 929 present. 930 HPET is the next generation timer replacing legacy 8254s. 931 The HPET provides a stable time base on SMP 932 systems, unlike the TSC, but it is more expensive to access, 933 as it is off-chip. The interface used is documented 934 in the HPET spec, revision 1. 935 936 You can safely choose Y here. However, HPET will only be 937 activated if the platform and the BIOS support this feature. 938 Otherwise the 8254 will be used for timing services. 939 940 Choose N to continue using the legacy 8254 timer. 941 942config HPET_EMULATE_RTC 943 def_bool y 944 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 945 946# Mark as expert because too many people got it wrong. 947# The code disables itself when not needed. 948config DMI 949 default y 950 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 951 bool "Enable DMI scanning" if EXPERT 952 help 953 Enabled scanning of DMI to identify machine quirks. Say Y 954 here unless you have verified that your setup is not 955 affected by entries in the DMI blacklist. Required by PNP 956 BIOS code. 957 958config GART_IOMMU 959 bool "Old AMD GART IOMMU support" 960 select IOMMU_HELPER 961 select SWIOTLB 962 depends on X86_64 && PCI && AMD_NB 963 help 964 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 965 GART based hardware IOMMUs. 966 967 The GART supports full DMA access for devices with 32-bit access 968 limitations, on systems with more than 3 GB. This is usually needed 969 for USB, sound, many IDE/SATA chipsets and some other devices. 970 971 Newer systems typically have a modern AMD IOMMU, supported via 972 the CONFIG_AMD_IOMMU=y config option. 973 974 In normal configurations this driver is only active when needed: 975 there's more than 3 GB of memory and the system contains a 976 32-bit limited device. 977 978 If unsure, say Y. 979 980config BOOT_VESA_SUPPORT 981 bool 982 help 983 If true, at least one selected framebuffer driver can take advantage 984 of VESA video modes set at an early boot stage via the vga= parameter. 985 986config MAXSMP 987 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 988 depends on X86_64 && SMP && DEBUG_KERNEL 989 select CPUMASK_OFFSTACK 990 help 991 Enable maximum number of CPUS and NUMA Nodes for this architecture. 992 If unsure, say N. 993 994# 995# The maximum number of CPUs supported: 996# 997# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 998# and which can be configured interactively in the 999# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 1000# 1001# The ranges are different on 32-bit and 64-bit kernels, depending on 1002# hardware capabilities and scalability features of the kernel. 1003# 1004# ( If MAXSMP is enabled we just use the highest possible value and disable 1005# interactive configuration. ) 1006# 1007 1008config NR_CPUS_RANGE_BEGIN 1009 int 1010 default NR_CPUS_RANGE_END if MAXSMP 1011 default 1 if !SMP 1012 default 2 1013 1014config NR_CPUS_RANGE_END 1015 int 1016 depends on X86_32 1017 default 8 if SMP 1018 default 1 if !SMP 1019 1020config NR_CPUS_RANGE_END 1021 int 1022 depends on X86_64 1023 default 8192 if SMP && CPUMASK_OFFSTACK 1024 default 512 if SMP && !CPUMASK_OFFSTACK 1025 default 1 if !SMP 1026 1027config NR_CPUS_DEFAULT 1028 int 1029 depends on X86_32 1030 default 8 if SMP 1031 default 1 if !SMP 1032 1033config NR_CPUS_DEFAULT 1034 int 1035 depends on X86_64 1036 default 8192 if MAXSMP 1037 default 64 if SMP 1038 default 1 if !SMP 1039 1040config NR_CPUS 1041 int "Maximum number of CPUs" if SMP && !MAXSMP 1042 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1043 default NR_CPUS_DEFAULT 1044 help 1045 This allows you to specify the maximum number of CPUs which this 1046 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1047 supported value is 8192, otherwise the maximum value is 512. The 1048 minimum value which makes sense is 2. 1049 1050 This is purely to save memory: each supported CPU adds about 8KB 1051 to the kernel image. 1052 1053config SCHED_MC_PRIO 1054 bool "CPU core priorities scheduler support" 1055 depends on SCHED_MC 1056 select X86_INTEL_PSTATE if CPU_SUP_INTEL 1057 select X86_AMD_PSTATE if CPU_SUP_AMD && ACPI 1058 select CPU_FREQ 1059 default y 1060 help 1061 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1062 core ordering determined at manufacturing time, which allows 1063 certain cores to reach higher turbo frequencies (when running 1064 single threaded workloads) than others. 1065 1066 Enabling this kernel feature teaches the scheduler about 1067 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1068 scheduler's CPU selection logic accordingly, so that higher 1069 overall system performance can be achieved. 1070 1071 This feature will have no effect on CPUs without this feature. 1072 1073 If unsure say Y here. 1074 1075config UP_LATE_INIT 1076 def_bool y 1077 depends on !SMP && X86_LOCAL_APIC 1078 1079config X86_UP_APIC 1080 bool "Local APIC support on uniprocessors" if !PCI_MSI 1081 default PCI_MSI 1082 depends on X86_32 && !SMP 1083 help 1084 A local APIC (Advanced Programmable Interrupt Controller) is an 1085 integrated interrupt controller in the CPU. If you have a single-CPU 1086 system which has a processor with a local APIC, you can say Y here to 1087 enable and use it. If you say Y here even though your machine doesn't 1088 have a local APIC, then the kernel will still run with no slowdown at 1089 all. The local APIC supports CPU-generated self-interrupts (timer, 1090 performance counters), and the NMI watchdog which detects hard 1091 lockups. 1092 1093config X86_UP_IOAPIC 1094 bool "IO-APIC support on uniprocessors" 1095 depends on X86_UP_APIC 1096 help 1097 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1098 SMP-capable replacement for PC-style interrupt controllers. Most 1099 SMP systems and many recent uniprocessor systems have one. 1100 1101 If you have a single-CPU system with an IO-APIC, you can say Y here 1102 to use it. If you say Y here even though your machine doesn't have 1103 an IO-APIC, then the kernel will still run with no slowdown at all. 1104 1105config X86_LOCAL_APIC 1106 def_bool y 1107 depends on X86_64 || SMP || X86_UP_APIC || PCI_MSI 1108 select IRQ_DOMAIN_HIERARCHY 1109 1110config ACPI_MADT_WAKEUP 1111 def_bool y 1112 depends on X86_64 1113 depends on ACPI 1114 depends on SMP 1115 depends on X86_LOCAL_APIC 1116 1117config X86_IO_APIC 1118 def_bool y 1119 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1120 1121config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1122 bool "Reroute for broken boot IRQs" 1123 depends on X86_IO_APIC 1124 help 1125 This option enables a workaround that fixes a source of 1126 spurious interrupts. This is recommended when threaded 1127 interrupt handling is used on systems where the generation of 1128 superfluous "boot interrupts" cannot be disabled. 1129 1130 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1131 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1132 kernel does during interrupt handling). On chipsets where this 1133 boot IRQ generation cannot be disabled, this workaround keeps 1134 the original IRQ line masked so that only the equivalent "boot 1135 IRQ" is delivered to the CPUs. The workaround also tells the 1136 kernel to set up the IRQ handler on the boot IRQ line. In this 1137 way only one interrupt is delivered to the kernel. Otherwise 1138 the spurious second interrupt may cause the kernel to bring 1139 down (vital) interrupt lines. 1140 1141 Only affects "broken" chipsets. Interrupt sharing may be 1142 increased on these systems. 1143 1144config X86_MCE 1145 bool "Machine Check / overheating reporting" 1146 select GENERIC_ALLOCATOR 1147 default y 1148 help 1149 Machine Check support allows the processor to notify the 1150 kernel if it detects a problem (e.g. overheating, data corruption). 1151 The action the kernel takes depends on the severity of the problem, 1152 ranging from warning messages to halting the machine. 1153 1154config X86_MCELOG_LEGACY 1155 bool "Support for deprecated /dev/mcelog character device" 1156 depends on X86_MCE 1157 help 1158 Enable support for /dev/mcelog which is needed by the old mcelog 1159 userspace logging daemon. Consider switching to the new generation 1160 rasdaemon solution. 1161 1162config X86_MCE_INTEL 1163 def_bool y 1164 prompt "Intel MCE features" 1165 depends on X86_MCE && X86_LOCAL_APIC 1166 help 1167 Additional support for intel specific MCE features such as 1168 the thermal monitor. 1169 1170config X86_MCE_AMD 1171 def_bool y 1172 prompt "AMD MCE features" 1173 depends on X86_MCE && X86_LOCAL_APIC 1174 help 1175 Additional support for AMD specific MCE features such as 1176 the DRAM Error Threshold. 1177 1178config X86_ANCIENT_MCE 1179 bool "Support for old Pentium 5 / WinChip machine checks" 1180 depends on X86_32 && X86_MCE 1181 help 1182 Include support for machine check handling on old Pentium 5 or WinChip 1183 systems. These typically need to be enabled explicitly on the command 1184 line. 1185 1186config X86_MCE_THRESHOLD 1187 depends on X86_MCE_AMD || X86_MCE_INTEL 1188 def_bool y 1189 1190config X86_MCE_INJECT 1191 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1192 tristate "Machine check injector support" 1193 help 1194 Provide support for injecting machine checks for testing purposes. 1195 If you don't know what a machine check is and you don't do kernel 1196 QA it is safe to say n. 1197 1198source "arch/x86/events/Kconfig" 1199 1200config X86_LEGACY_VM86 1201 bool "Legacy VM86 support" 1202 depends on X86_32 1203 help 1204 This option allows user programs to put the CPU into V8086 1205 mode, which is an 80286-era approximation of 16-bit real mode. 1206 1207 Some very old versions of X and/or vbetool require this option 1208 for user mode setting. Similarly, DOSEMU will use it if 1209 available to accelerate real mode DOS programs. However, any 1210 recent version of DOSEMU, X, or vbetool should be fully 1211 functional even without kernel VM86 support, as they will all 1212 fall back to software emulation. Nevertheless, if you are using 1213 a 16-bit DOS program where 16-bit performance matters, vm86 1214 mode might be faster than emulation and you might want to 1215 enable this option. 1216 1217 Note that any app that works on a 64-bit kernel is unlikely to 1218 need this option, as 64-bit kernels don't, and can't, support 1219 V8086 mode. This option is also unrelated to 16-bit protected 1220 mode and is not needed to run most 16-bit programs under Wine. 1221 1222 Enabling this option increases the complexity of the kernel 1223 and slows down exception handling a tiny bit. 1224 1225 If unsure, say N here. 1226 1227config VM86 1228 bool 1229 default X86_LEGACY_VM86 1230 1231config X86_16BIT 1232 bool "Enable support for 16-bit segments" if EXPERT 1233 default y 1234 depends on MODIFY_LDT_SYSCALL 1235 help 1236 This option is required by programs like Wine to run 16-bit 1237 protected mode legacy code on x86 processors. Disabling 1238 this option saves about 300 bytes on i386, or around 6K text 1239 plus 16K runtime memory on x86-64, 1240 1241config X86_ESPFIX32 1242 def_bool y 1243 depends on X86_16BIT && X86_32 1244 1245config X86_ESPFIX64 1246 def_bool y 1247 depends on X86_16BIT && X86_64 1248 1249config X86_VSYSCALL_EMULATION 1250 bool "Enable vsyscall emulation" if EXPERT 1251 default y 1252 depends on X86_64 1253 help 1254 This enables emulation of the legacy vsyscall page. Disabling 1255 it is roughly equivalent to booting with vsyscall=none, except 1256 that it will also disable the helpful warning if a program 1257 tries to use a vsyscall. With this option set to N, offending 1258 programs will just segfault, citing addresses of the form 1259 0xffffffffff600?00. 1260 1261 This option is required by many programs built before 2013, and 1262 care should be used even with newer programs if set to N. 1263 1264 Disabling this option saves about 7K of kernel size and 1265 possibly 4K of additional runtime pagetable memory. 1266 1267config X86_IOPL_IOPERM 1268 bool "IOPERM and IOPL Emulation" 1269 default y 1270 help 1271 This enables the ioperm() and iopl() syscalls which are necessary 1272 for legacy applications. 1273 1274 Legacy IOPL support is an overbroad mechanism which allows user 1275 space aside of accessing all 65536 I/O ports also to disable 1276 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1277 capabilities and permission from potentially active security 1278 modules. 1279 1280 The emulation restricts the functionality of the syscall to 1281 only allowing the full range I/O port access, but prevents the 1282 ability to disable interrupts from user space which would be 1283 granted if the hardware IOPL mechanism would be used. 1284 1285config TOSHIBA 1286 tristate "Toshiba Laptop support" 1287 depends on X86_32 1288 help 1289 This adds a driver to safely access the System Management Mode of 1290 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1291 not work on models with a Phoenix BIOS. The System Management Mode 1292 is used to set the BIOS and power saving options on Toshiba portables. 1293 1294 For information on utilities to make use of this driver see the 1295 Toshiba Linux utilities web site at: 1296 <http://www.buzzard.org.uk/toshiba/>. 1297 1298 Say Y if you intend to run this kernel on a Toshiba portable. 1299 Say N otherwise. 1300 1301config X86_REBOOTFIXUPS 1302 bool "Enable X86 board specific fixups for reboot" 1303 depends on X86_32 1304 help 1305 This enables chipset and/or board specific fixups to be done 1306 in order to get reboot to work correctly. This is only needed on 1307 some combinations of hardware and BIOS. The symptom, for which 1308 this config is intended, is when reboot ends with a stalled/hung 1309 system. 1310 1311 Currently, the only fixup is for the Geode machines using 1312 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1313 1314 Say Y if you want to enable the fixup. Currently, it's safe to 1315 enable this option even if you don't need it. 1316 Say N otherwise. 1317 1318config MICROCODE 1319 def_bool y 1320 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1321 select CRYPTO_LIB_SHA256 if CPU_SUP_AMD 1322 1323config MICROCODE_INITRD32 1324 def_bool y 1325 depends on MICROCODE && X86_32 && BLK_DEV_INITRD 1326 1327config MICROCODE_LATE_LOADING 1328 bool "Late microcode loading (DANGEROUS)" 1329 default n 1330 depends on MICROCODE && SMP 1331 help 1332 Loading microcode late, when the system is up and executing instructions 1333 is a tricky business and should be avoided if possible. Just the sequence 1334 of synchronizing all cores and SMT threads is one fragile dance which does 1335 not guarantee that cores might not softlock after the loading. Therefore, 1336 use this at your own risk. Late loading taints the kernel unless the 1337 microcode header indicates that it is safe for late loading via the 1338 minimal revision check. This minimal revision check can be enforced on 1339 the kernel command line with "microcode=force_minrev". 1340 1341config MICROCODE_LATE_FORCE_MINREV 1342 bool "Enforce late microcode loading minimal revision check" 1343 default n 1344 depends on MICROCODE_LATE_LOADING 1345 help 1346 To prevent that users load microcode late which modifies already 1347 in use features, newer microcode patches have a minimum revision field 1348 in the microcode header, which tells the kernel which minimum 1349 revision must be active in the CPU to safely load that new microcode 1350 late into the running system. If disabled the check will not 1351 be enforced but the kernel will be tainted when the minimal 1352 revision check fails. 1353 1354 This minimal revision check can also be controlled via the 1355 "microcode=force_minrev" parameter on the kernel command line. 1356 1357 If unsure say Y. 1358 1359config MICROCODE_DBG 1360 bool "Enable microcode loader debugging" 1361 default n 1362 depends on MICROCODE 1363 help 1364 Enable code which allows to debug the microcode loader. When running 1365 in a guest the patch loading is simulated but everything else 1366 related to patch parsing and handling is done as on baremetal with 1367 the purpose of debugging solely the software side of things. On 1368 baremetal, it simply dumps additional debugging information during 1369 normal operation. 1370 1371 You almost certainly want to say n here. 1372 1373config X86_MSR 1374 tristate "/dev/cpu/*/msr - Model-specific register support" 1375 help 1376 This device gives privileged processes access to the x86 1377 Model-Specific Registers (MSRs). It is a character device with 1378 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1379 MSR accesses are directed to a specific CPU on multi-processor 1380 systems. 1381 1382config X86_CPUID 1383 tristate "/dev/cpu/*/cpuid - CPU information support" 1384 help 1385 This device gives processes access to the x86 CPUID instruction to 1386 be executed on a specific processor. It is a character device 1387 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1388 /dev/cpu/31/cpuid. 1389 1390config HIGHMEM4G 1391 bool "High Memory Support" 1392 depends on X86_32 1393 help 1394 Linux can use up to 4 Gigabytes of physical memory on x86 systems. 1395 However, the address space of 32-bit x86 processors is only 4 1396 Gigabytes large. That means that, if you have a large amount of 1397 physical memory, not all of it can be "permanently mapped" by the 1398 kernel. The physical memory that's not permanently mapped is called 1399 "high memory". 1400 1401 If you are compiling a kernel which will never run on a machine with 1402 more than 1 Gigabyte total physical RAM, answer "off" here (default 1403 choice and suitable for most users). This will result in a "3GB/1GB" 1404 split: 3GB are mapped so that each process sees a 3GB virtual memory 1405 space and the remaining part of the 4GB virtual memory space is used 1406 by the kernel to permanently map as much physical memory as 1407 possible. 1408 1409 If the machine has between 1 and 4 Gigabytes physical RAM, then 1410 answer "Y" here. 1411 1412 If unsure, say N. 1413 1414choice 1415 prompt "Memory split" if EXPERT 1416 default VMSPLIT_3G 1417 depends on X86_32 1418 help 1419 Select the desired split between kernel and user memory. 1420 1421 If the address range available to the kernel is less than the 1422 physical memory installed, the remaining memory will be available 1423 as "high memory". Accessing high memory is a little more costly 1424 than low memory, as it needs to be mapped into the kernel first. 1425 Note that increasing the kernel address space limits the range 1426 available to user programs, making the address space there 1427 tighter. Selecting anything other than the default 3G/1G split 1428 will also likely make your kernel incompatible with binary-only 1429 kernel modules. 1430 1431 If you are not absolutely sure what you are doing, leave this 1432 option alone! 1433 1434 config VMSPLIT_3G 1435 bool "3G/1G user/kernel split" 1436 config VMSPLIT_3G_OPT 1437 depends on !X86_PAE 1438 bool "3G/1G user/kernel split (for full 1G low memory)" 1439 config VMSPLIT_2G 1440 bool "2G/2G user/kernel split" 1441 config VMSPLIT_2G_OPT 1442 depends on !X86_PAE 1443 bool "2G/2G user/kernel split (for full 2G low memory)" 1444 config VMSPLIT_1G 1445 bool "1G/3G user/kernel split" 1446endchoice 1447 1448config PAGE_OFFSET 1449 hex 1450 default 0xB0000000 if VMSPLIT_3G_OPT 1451 default 0x80000000 if VMSPLIT_2G 1452 default 0x78000000 if VMSPLIT_2G_OPT 1453 default 0x40000000 if VMSPLIT_1G 1454 default 0xC0000000 1455 depends on X86_32 1456 1457config HIGHMEM 1458 def_bool HIGHMEM4G 1459 1460config X86_PAE 1461 bool "PAE (Physical Address Extension) Support" 1462 depends on X86_32 && X86_HAVE_PAE 1463 select PHYS_ADDR_T_64BIT 1464 help 1465 PAE is required for NX support, and furthermore enables 1466 larger swapspace support for non-overcommit purposes. It 1467 has the cost of more pagetable lookup overhead, and also 1468 consumes more pagetable space per process. 1469 1470config X86_DIRECT_GBPAGES 1471 def_bool y 1472 depends on X86_64 1473 help 1474 Certain kernel features effectively disable kernel 1475 linear 1 GB mappings (even if the CPU otherwise 1476 supports them), so don't confuse the user by printing 1477 that we have them enabled. 1478 1479config X86_CPA_STATISTICS 1480 bool "Enable statistic for Change Page Attribute" 1481 depends on DEBUG_FS 1482 help 1483 Expose statistics about the Change Page Attribute mechanism, which 1484 helps to determine the effectiveness of preserving large and huge 1485 page mappings when mapping protections are changed. 1486 1487config X86_MEM_ENCRYPT 1488 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1489 select DYNAMIC_PHYSICAL_MASK 1490 def_bool n 1491 1492config AMD_MEM_ENCRYPT 1493 bool "AMD Secure Memory Encryption (SME) support" 1494 depends on X86_64 && CPU_SUP_AMD 1495 depends on EFI_STUB 1496 select DMA_COHERENT_POOL 1497 select ARCH_USE_MEMREMAP_PROT 1498 select INSTRUCTION_DECODER 1499 select ARCH_HAS_CC_PLATFORM 1500 select X86_MEM_ENCRYPT 1501 select UNACCEPTED_MEMORY 1502 select CRYPTO_LIB_AES_GCM 1503 help 1504 Say yes to enable support for the encryption of system memory. 1505 This requires an AMD processor that supports Secure Memory 1506 Encryption (SME). 1507 1508# Common NUMA Features 1509config NUMA 1510 bool "NUMA Memory Allocation and Scheduler Support" 1511 depends on SMP 1512 depends on X86_64 1513 select USE_PERCPU_NUMA_NODE_ID 1514 select OF_NUMA if OF 1515 help 1516 Enable NUMA (Non-Uniform Memory Access) support. 1517 1518 The kernel will try to allocate memory used by a CPU on the 1519 local memory controller of the CPU and add some more 1520 NUMA awareness to the kernel. 1521 1522 For 64-bit this is recommended if the system is Intel Core i7 1523 (or later), AMD Opteron, or EM64T NUMA. 1524 1525 Otherwise, you should say N. 1526 1527config AMD_NUMA 1528 def_bool y 1529 prompt "Old style AMD Opteron NUMA detection" 1530 depends on X86_64 && NUMA && PCI 1531 help 1532 Enable AMD NUMA node topology detection. You should say Y here if 1533 you have a multi processor AMD system. This uses an old method to 1534 read the NUMA configuration directly from the builtin Northbridge 1535 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1536 which also takes priority if both are compiled in. 1537 1538config X86_64_ACPI_NUMA 1539 def_bool y 1540 prompt "ACPI NUMA detection" 1541 depends on X86_64 && NUMA && ACPI && PCI 1542 select ACPI_NUMA 1543 help 1544 Enable ACPI SRAT based node topology detection. 1545 1546config NODES_SHIFT 1547 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1548 range 1 10 1549 default "10" if MAXSMP 1550 default "6" if X86_64 1551 default "3" 1552 depends on NUMA 1553 help 1554 Specify the maximum number of NUMA Nodes available on the target 1555 system. Increases memory reserved to accommodate various tables. 1556 1557config ARCH_FLATMEM_ENABLE 1558 def_bool y 1559 depends on X86_32 && !NUMA 1560 1561config ARCH_SPARSEMEM_ENABLE 1562 def_bool y 1563 select SPARSEMEM_STATIC if X86_32 1564 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1565 1566config ARCH_SPARSEMEM_DEFAULT 1567 def_bool X86_64 || (NUMA && X86_32) 1568 1569config ARCH_SELECT_MEMORY_MODEL 1570 def_bool y 1571 depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE 1572 1573config ARCH_MEMORY_PROBE 1574 bool "Enable sysfs memory/probe interface" 1575 depends on MEMORY_HOTPLUG 1576 help 1577 This option enables a sysfs memory/probe interface for testing. 1578 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1579 If you are unsure how to answer this question, answer N. 1580 1581config ARCH_PROC_KCORE_TEXT 1582 def_bool y 1583 depends on X86_64 && PROC_KCORE 1584 1585config ILLEGAL_POINTER_VALUE 1586 hex 1587 default 0 if X86_32 1588 default 0xdead000000000000 if X86_64 1589 1590config X86_PMEM_LEGACY_DEVICE 1591 bool 1592 1593config X86_PMEM_LEGACY 1594 tristate "Support non-standard NVDIMMs and ADR protected memory" 1595 depends on PHYS_ADDR_T_64BIT 1596 depends on BLK_DEV 1597 select X86_PMEM_LEGACY_DEVICE 1598 select NUMA_KEEP_MEMINFO if NUMA 1599 select LIBNVDIMM 1600 help 1601 Treat memory marked using the non-standard e820 type of 12 as used 1602 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1603 The kernel will offer these regions to the 'pmem' driver so 1604 they can be used for persistent storage. 1605 1606 Say Y if unsure. 1607 1608config X86_CHECK_BIOS_CORRUPTION 1609 bool "Check for low memory corruption" 1610 help 1611 Periodically check for memory corruption in low memory, which 1612 is suspected to be caused by BIOS. Even when enabled in the 1613 configuration, it is disabled at runtime. Enable it by 1614 setting "memory_corruption_check=1" on the kernel command 1615 line. By default it scans the low 64k of memory every 60 1616 seconds; see the memory_corruption_check_size and 1617 memory_corruption_check_period parameters in 1618 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1619 1620 When enabled with the default parameters, this option has 1621 almost no overhead, as it reserves a relatively small amount 1622 of memory and scans it infrequently. It both detects corruption 1623 and prevents it from affecting the running system. 1624 1625 It is, however, intended as a diagnostic tool; if repeatable 1626 BIOS-originated corruption always affects the same memory, 1627 you can use memmap= to prevent the kernel from using that 1628 memory. 1629 1630config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1631 bool "Set the default setting of memory_corruption_check" 1632 depends on X86_CHECK_BIOS_CORRUPTION 1633 default y 1634 help 1635 Set whether the default state of memory_corruption_check is 1636 on or off. 1637 1638config MTRR 1639 def_bool y 1640 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1641 help 1642 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1643 the Memory Type Range Registers (MTRRs) may be used to control 1644 processor access to memory ranges. This is most useful if you have 1645 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1646 allows bus write transfers to be combined into a larger transfer 1647 before bursting over the PCI/AGP bus. This can increase performance 1648 of image write operations 2.5 times or more. Saying Y here creates a 1649 /proc/mtrr file which may be used to manipulate your processor's 1650 MTRRs. Typically the X server should use this. 1651 1652 This code has a reasonably generic interface so that similar 1653 control registers on other processors can be easily supported 1654 as well: 1655 1656 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1657 Registers (ARRs) which provide a similar functionality to MTRRs. For 1658 these, the ARRs are used to emulate the MTRRs. 1659 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1660 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1661 write-combining. All of these processors are supported by this code 1662 and it makes sense to say Y here if you have one of them. 1663 1664 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1665 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1666 can lead to all sorts of problems, so it's good to say Y here. 1667 1668 You can safely say Y even if your machine doesn't have MTRRs, you'll 1669 just add about 9 KB to your kernel. 1670 1671 See <file:Documentation/arch/x86/mtrr.rst> for more information. 1672 1673config MTRR_SANITIZER 1674 def_bool y 1675 prompt "MTRR cleanup support" 1676 depends on MTRR 1677 help 1678 Convert MTRR layout from continuous to discrete, so X drivers can 1679 add writeback entries. 1680 1681 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1682 The largest mtrr entry size for a continuous block can be set with 1683 mtrr_chunk_size. 1684 1685 If unsure, say Y. 1686 1687config MTRR_SANITIZER_ENABLE_DEFAULT 1688 int "MTRR cleanup enable value (0-1)" 1689 range 0 1 1690 default "0" 1691 depends on MTRR_SANITIZER 1692 help 1693 Enable mtrr cleanup default value 1694 1695config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1696 int "MTRR cleanup spare reg num (0-7)" 1697 range 0 7 1698 default "1" 1699 depends on MTRR_SANITIZER 1700 help 1701 mtrr cleanup spare entries default, it can be changed via 1702 mtrr_spare_reg_nr=N on the kernel command line. 1703 1704config X86_PAT 1705 def_bool y 1706 prompt "x86 PAT support" if EXPERT 1707 depends on MTRR 1708 select ARCH_USES_PG_ARCH_2 1709 help 1710 Use PAT attributes to setup page level cache control. 1711 1712 PATs are the modern equivalents of MTRRs and are much more 1713 flexible than MTRRs. 1714 1715 Say N here if you see bootup problems (boot crash, boot hang, 1716 spontaneous reboots) or a non-working video driver. 1717 1718 If unsure, say Y. 1719 1720config X86_UMIP 1721 def_bool y 1722 prompt "User Mode Instruction Prevention" if EXPERT 1723 help 1724 User Mode Instruction Prevention (UMIP) is a security feature in 1725 some x86 processors. If enabled, a general protection fault is 1726 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1727 executed in user mode. These instructions unnecessarily expose 1728 information about the hardware state. 1729 1730 The vast majority of applications do not use these instructions. 1731 For the very few that do, software emulation is provided in 1732 specific cases in protected and virtual-8086 modes. Emulated 1733 results are dummy. 1734 1735config CC_HAS_IBT 1736 # GCC >= 9 and binutils >= 2.29 1737 # Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654 1738 def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || CC_IS_CLANG) && \ 1739 $(as-instr,endbr64) 1740 1741config X86_CET 1742 def_bool n 1743 help 1744 CET features configured (Shadow stack or IBT) 1745 1746config X86_KERNEL_IBT 1747 prompt "Indirect Branch Tracking" 1748 def_bool y 1749 depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL 1750 select OBJTOOL 1751 select X86_CET 1752 help 1753 Build the kernel with support for Indirect Branch Tracking, a 1754 hardware support course-grain forward-edge Control Flow Integrity 1755 protection. It enforces that all indirect calls must land on 1756 an ENDBR instruction, as such, the compiler will instrument the 1757 code with them to make this happen. 1758 1759 In addition to building the kernel with IBT, seal all functions that 1760 are not indirect call targets, avoiding them ever becoming one. 1761 1762 This requires LTO like objtool runs and will slow down the build. It 1763 does significantly reduce the number of ENDBR instructions in the 1764 kernel image. 1765 1766config X86_INTEL_MEMORY_PROTECTION_KEYS 1767 prompt "Memory Protection Keys" 1768 def_bool y 1769 # Note: only available in 64-bit mode 1770 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1771 select ARCH_USES_HIGH_VMA_FLAGS 1772 select ARCH_HAS_PKEYS 1773 help 1774 Memory Protection Keys provides a mechanism for enforcing 1775 page-based protections, but without requiring modification of the 1776 page tables when an application changes protection domains. 1777 1778 For details, see Documentation/core-api/protection-keys.rst 1779 1780 If unsure, say y. 1781 1782config ARCH_PKEY_BITS 1783 int 1784 default 4 1785 1786choice 1787 prompt "TSX enable mode" 1788 depends on CPU_SUP_INTEL 1789 default X86_INTEL_TSX_MODE_AUTO 1790 help 1791 Intel's TSX (Transactional Synchronization Extensions) feature 1792 allows to optimize locking protocols through lock elision which 1793 can lead to a noticeable performance boost. 1794 1795 On the other hand it has been shown that TSX can be exploited 1796 to form side channel attacks (e.g. TAA) and chances are there 1797 will be more of those attacks discovered in the future. 1798 1799 Therefore TSX is not enabled by default (aka tsx=off). An admin 1800 might override this decision by tsx=on the command line parameter. 1801 Even with TSX enabled, the kernel will attempt to enable the best 1802 possible TAA mitigation setting depending on the microcode available 1803 for the particular machine. 1804 1805 This option allows to set the default tsx mode between tsx=on, =off 1806 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1807 details. 1808 1809 Say off if not sure, auto if TSX is in use but it should be used on safe 1810 platforms or on if TSX is in use and the security aspect of tsx is not 1811 relevant. 1812 1813config X86_INTEL_TSX_MODE_OFF 1814 bool "off" 1815 help 1816 TSX is disabled if possible - equals to tsx=off command line parameter. 1817 1818config X86_INTEL_TSX_MODE_ON 1819 bool "on" 1820 help 1821 TSX is always enabled on TSX capable HW - equals the tsx=on command 1822 line parameter. 1823 1824config X86_INTEL_TSX_MODE_AUTO 1825 bool "auto" 1826 help 1827 TSX is enabled on TSX capable HW that is believed to be safe against 1828 side channel attacks- equals the tsx=auto command line parameter. 1829endchoice 1830 1831config X86_SGX 1832 bool "Software Guard eXtensions (SGX)" 1833 depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC 1834 select CRYPTO_LIB_SHA256 1835 select MMU_NOTIFIER 1836 select NUMA_KEEP_MEMINFO if NUMA 1837 select XARRAY_MULTI 1838 help 1839 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1840 that can be used by applications to set aside private regions of code 1841 and data, referred to as enclaves. An enclave's private memory can 1842 only be accessed by code running within the enclave. Accesses from 1843 outside the enclave, including other enclaves, are disallowed by 1844 hardware. 1845 1846 If unsure, say N. 1847 1848config X86_USER_SHADOW_STACK 1849 bool "X86 userspace shadow stack" 1850 depends on AS_WRUSS 1851 depends on X86_64 1852 depends on PER_VMA_LOCK 1853 select ARCH_USES_HIGH_VMA_FLAGS 1854 select ARCH_HAS_USER_SHADOW_STACK 1855 select X86_CET 1856 help 1857 Shadow stack protection is a hardware feature that detects function 1858 return address corruption. This helps mitigate ROP attacks. 1859 Applications must be enabled to use it, and old userspace does not 1860 get protection "for free". 1861 1862 CPUs supporting shadow stacks were first released in 2020. 1863 1864 See Documentation/arch/x86/shstk.rst for more information. 1865 1866 If unsure, say N. 1867 1868config INTEL_TDX_HOST 1869 bool "Intel Trust Domain Extensions (TDX) host support" 1870 depends on CPU_SUP_INTEL 1871 depends on X86_64 1872 depends on KVM_INTEL 1873 depends on X86_X2APIC 1874 select ARCH_KEEP_MEMBLOCK 1875 depends on CONTIG_ALLOC 1876 depends on X86_MCE 1877 help 1878 Intel Trust Domain Extensions (TDX) protects guest VMs from malicious 1879 host and certain physical attacks. This option enables necessary TDX 1880 support in the host kernel to run confidential VMs. 1881 1882 If unsure, say N. 1883 1884config EFI 1885 bool "EFI runtime service support" 1886 depends on ACPI 1887 select UCS2_STRING 1888 select EFI_RUNTIME_WRAPPERS 1889 select ARCH_USE_MEMREMAP_PROT 1890 select EFI_RUNTIME_MAP if KEXEC_CORE 1891 help 1892 This enables the kernel to use EFI runtime services that are 1893 available (such as the EFI variable services). 1894 1895 This option is only useful on systems that have EFI firmware. 1896 In addition, you should use the latest ELILO loader available 1897 at <http://elilo.sourceforge.net> in order to take advantage 1898 of EFI runtime services. However, even with this option, the 1899 resultant kernel should continue to boot on existing non-EFI 1900 platforms. 1901 1902config EFI_STUB 1903 bool "EFI stub support" 1904 depends on EFI 1905 select RELOCATABLE 1906 help 1907 This kernel feature allows a bzImage to be loaded directly 1908 by EFI firmware without the use of a bootloader. 1909 1910 See Documentation/admin-guide/efi-stub.rst for more information. 1911 1912config EFI_HANDOVER_PROTOCOL 1913 bool "EFI handover protocol (DEPRECATED)" 1914 depends on EFI_STUB 1915 default y 1916 help 1917 Select this in order to include support for the deprecated EFI 1918 handover protocol, which defines alternative entry points into the 1919 EFI stub. This is a practice that has no basis in the UEFI 1920 specification, and requires a priori knowledge on the part of the 1921 bootloader about Linux/x86 specific ways of passing the command line 1922 and initrd, and where in memory those assets may be loaded. 1923 1924 If in doubt, say Y. Even though the corresponding support is not 1925 present in upstream GRUB or other bootloaders, most distros build 1926 GRUB with numerous downstream patches applied, and may rely on the 1927 handover protocol as as result. 1928 1929config EFI_MIXED 1930 bool "EFI mixed-mode support" 1931 depends on EFI_STUB && X86_64 1932 help 1933 Enabling this feature allows a 64-bit kernel to be booted 1934 on a 32-bit firmware, provided that your CPU supports 64-bit 1935 mode. 1936 1937 Note that it is not possible to boot a mixed-mode enabled 1938 kernel via the EFI boot stub - a bootloader that supports 1939 the EFI handover protocol must be used. 1940 1941 If unsure, say N. 1942 1943config EFI_RUNTIME_MAP 1944 bool "Export EFI runtime maps to sysfs" if EXPERT 1945 depends on EFI 1946 help 1947 Export EFI runtime memory regions to /sys/firmware/efi/runtime-map. 1948 That memory map is required by the 2nd kernel to set up EFI virtual 1949 mappings after kexec, but can also be used for debugging purposes. 1950 1951 See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map. 1952 1953source "kernel/Kconfig.hz" 1954 1955config ARCH_SUPPORTS_KEXEC 1956 def_bool y 1957 1958config ARCH_SUPPORTS_KEXEC_FILE 1959 def_bool X86_64 1960 1961config ARCH_SELECTS_KEXEC_FILE 1962 def_bool y 1963 depends on KEXEC_FILE 1964 select HAVE_IMA_KEXEC if IMA 1965 1966config ARCH_SUPPORTS_KEXEC_PURGATORY 1967 def_bool y 1968 1969config ARCH_SUPPORTS_KEXEC_SIG 1970 def_bool y 1971 1972config ARCH_SUPPORTS_KEXEC_SIG_FORCE 1973 def_bool y 1974 1975config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG 1976 def_bool y 1977 1978config ARCH_SUPPORTS_KEXEC_JUMP 1979 def_bool y 1980 1981config ARCH_SUPPORTS_KEXEC_HANDOVER 1982 def_bool X86_64 1983 1984config ARCH_SUPPORTS_CRASH_DUMP 1985 def_bool X86_64 || (X86_32 && HIGHMEM) 1986 1987config ARCH_DEFAULT_CRASH_DUMP 1988 def_bool y 1989 1990config ARCH_SUPPORTS_CRASH_HOTPLUG 1991 def_bool y 1992 1993config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION 1994 def_bool CRASH_RESERVE 1995 1996config PHYSICAL_START 1997 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 1998 default "0x1000000" 1999 help 2000 This gives the physical address where the kernel is loaded. 2001 2002 If the kernel is not relocatable (CONFIG_RELOCATABLE=n) then bzImage 2003 will decompress itself to above physical address and run from there. 2004 Otherwise, bzImage will run from the address where it has been loaded 2005 by the boot loader. The only exception is if it is loaded below the 2006 above physical address, in which case it will relocate itself there. 2007 2008 In normal kdump cases one does not have to set/change this option 2009 as now bzImage can be compiled as a completely relocatable image 2010 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2011 address. This option is mainly useful for the folks who don't want 2012 to use a bzImage for capturing the crash dump and want to use a 2013 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2014 to be specifically compiled to run from a specific memory area 2015 (normally a reserved region) and this option comes handy. 2016 2017 So if you are using bzImage for capturing the crash dump, 2018 leave the value here unchanged to 0x1000000 and set 2019 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2020 for capturing the crash dump change this value to start of 2021 the reserved region. In other words, it can be set based on 2022 the "X" value as specified in the "crashkernel=YM@XM" 2023 command line boot parameter passed to the panic-ed 2024 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2025 for more details about crash dumps. 2026 2027 Usage of bzImage for capturing the crash dump is recommended as 2028 one does not have to build two kernels. Same kernel can be used 2029 as production kernel and capture kernel. Above option should have 2030 gone away after relocatable bzImage support is introduced. But it 2031 is present because there are users out there who continue to use 2032 vmlinux for dump capture. This option should go away down the 2033 line. 2034 2035 Don't change this unless you know what you are doing. 2036 2037config RELOCATABLE 2038 bool "Build a relocatable kernel" 2039 default y 2040 help 2041 This builds a kernel image that retains relocation information 2042 so it can be loaded someplace besides the default 1MB. 2043 The relocations tend to make the kernel binary about 10% larger, 2044 but are discarded at runtime. 2045 2046 One use is for the kexec on panic case where the recovery kernel 2047 must live at a different physical address than the primary 2048 kernel. 2049 2050 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2051 it has been loaded at and the compile time physical address 2052 (CONFIG_PHYSICAL_START) is used as the minimum location. 2053 2054config RANDOMIZE_BASE 2055 bool "Randomize the address of the kernel image (KASLR)" 2056 depends on RELOCATABLE 2057 default y 2058 help 2059 In support of Kernel Address Space Layout Randomization (KASLR), 2060 this randomizes the physical address at which the kernel image 2061 is decompressed and the virtual address where the kernel 2062 image is mapped, as a security feature that deters exploit 2063 attempts relying on knowledge of the location of kernel 2064 code internals. 2065 2066 On 64-bit, the kernel physical and virtual addresses are 2067 randomized separately. The physical address will be anywhere 2068 between 16MB and the top of physical memory (up to 64TB). The 2069 virtual address will be randomized from 16MB up to 1GB (9 bits 2070 of entropy). Note that this also reduces the memory space 2071 available to kernel modules from 1.5GB to 1GB. 2072 2073 On 32-bit, the kernel physical and virtual addresses are 2074 randomized together. They will be randomized from 16MB up to 2075 512MB (8 bits of entropy). 2076 2077 Entropy is generated using the RDRAND instruction if it is 2078 supported. If RDTSC is supported, its value is mixed into 2079 the entropy pool as well. If neither RDRAND nor RDTSC are 2080 supported, then entropy is read from the i8254 timer. The 2081 usable entropy is limited by the kernel being built using 2082 2GB addressing, and that PHYSICAL_ALIGN must be at a 2083 minimum of 2MB. As a result, only 10 bits of entropy are 2084 theoretically possible, but the implementations are further 2085 limited due to memory layouts. 2086 2087 If unsure, say Y. 2088 2089# Relocation on x86 needs some additional build support 2090config X86_NEED_RELOCS 2091 def_bool y 2092 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2093 select ARCH_VMLINUX_NEEDS_RELOCS 2094 2095config PHYSICAL_ALIGN 2096 hex "Alignment value to which kernel should be aligned" 2097 default "0x200000" 2098 range 0x2000 0x1000000 if X86_32 2099 range 0x200000 0x1000000 if X86_64 2100 help 2101 This value puts the alignment restrictions on physical address 2102 where kernel is loaded and run from. Kernel is compiled for an 2103 address which meets above alignment restriction. 2104 2105 If bootloader loads the kernel at a non-aligned address and 2106 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2107 address aligned to above value and run from there. 2108 2109 If bootloader loads the kernel at a non-aligned address and 2110 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2111 load address and decompress itself to the address it has been 2112 compiled for and run from there. The address for which kernel is 2113 compiled already meets above alignment restrictions. Hence the 2114 end result is that kernel runs from a physical address meeting 2115 above alignment restrictions. 2116 2117 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2118 this value must be a multiple of 0x200000. 2119 2120 Don't change this unless you know what you are doing. 2121 2122config RANDOMIZE_MEMORY 2123 bool "Randomize the kernel memory sections" 2124 depends on X86_64 2125 depends on RANDOMIZE_BASE 2126 default RANDOMIZE_BASE 2127 help 2128 Randomizes the base virtual address of kernel memory sections 2129 (physical memory mapping, vmalloc & vmemmap). This security feature 2130 makes exploits relying on predictable memory locations less reliable. 2131 2132 The order of allocations remains unchanged. Entropy is generated in 2133 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2134 configuration have in average 30,000 different possible virtual 2135 addresses for each memory section. 2136 2137 If unsure, say Y. 2138 2139config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2140 hex "Physical memory mapping padding" if EXPERT 2141 depends on RANDOMIZE_MEMORY 2142 default "0xa" if MEMORY_HOTPLUG 2143 default "0x0" 2144 range 0x1 0x40 if MEMORY_HOTPLUG 2145 range 0x0 0x40 2146 help 2147 Define the padding in terabytes added to the existing physical 2148 memory size during kernel memory randomization. It is useful 2149 for memory hotplug support but reduces the entropy available for 2150 address randomization. 2151 2152 If unsure, leave at the default value. 2153 2154config ADDRESS_MASKING 2155 bool "Linear Address Masking support" 2156 depends on X86_64 2157 depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS 2158 help 2159 Linear Address Masking (LAM) modifies the checking that is applied 2160 to 64-bit linear addresses, allowing software to use of the 2161 untranslated address bits for metadata. 2162 2163 The capability can be used for efficient address sanitizers (ASAN) 2164 implementation and for optimizations in JITs. 2165 2166config HOTPLUG_CPU 2167 def_bool y 2168 depends on SMP 2169 2170config COMPAT_VDSO 2171 def_bool n 2172 prompt "Workaround for glibc 2.3.2 / 2.3.3 (released in year 2003/2004)" 2173 depends on COMPAT_32 2174 help 2175 Certain buggy versions of glibc will crash if they are 2176 presented with a 32-bit vDSO that is not mapped at the address 2177 indicated in its segment table. 2178 2179 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2180 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2181 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2182 the only released version with the bug, but OpenSUSE 9 2183 contains a buggy "glibc 2.3.2". 2184 2185 The symptom of the bug is that everything crashes on startup, saying: 2186 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2187 2188 Saying Y here changes the default value of the vdso32 boot 2189 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2190 This works around the glibc bug but hurts performance. 2191 2192 If unsure, say N: if you are compiling your own kernel, you 2193 are unlikely to be using a buggy version of glibc. 2194 2195choice 2196 prompt "vsyscall table for legacy applications" 2197 depends on X86_64 2198 default LEGACY_VSYSCALL_XONLY 2199 help 2200 Legacy user code that does not know how to find the vDSO expects 2201 to be able to issue three syscalls by calling fixed addresses in 2202 kernel space. Since this location is not randomized with ASLR, 2203 it can be used to assist security vulnerability exploitation. 2204 2205 This setting can be changed at boot time via the kernel command 2206 line parameter vsyscall=[emulate|xonly|none]. Emulate mode 2207 is deprecated and can only be enabled using the kernel command 2208 line. 2209 2210 On a system with recent enough glibc (2.14 or newer) and no 2211 static binaries, you can say None without a performance penalty 2212 to improve security. 2213 2214 If unsure, select "Emulate execution only". 2215 2216 config LEGACY_VSYSCALL_XONLY 2217 bool "Emulate execution only" 2218 help 2219 The kernel traps and emulates calls into the fixed vsyscall 2220 address mapping and does not allow reads. This 2221 configuration is recommended when userspace might use the 2222 legacy vsyscall area but support for legacy binary 2223 instrumentation of legacy code is not needed. It mitigates 2224 certain uses of the vsyscall area as an ASLR-bypassing 2225 buffer. 2226 2227 config LEGACY_VSYSCALL_NONE 2228 bool "None" 2229 help 2230 There will be no vsyscall mapping at all. This will 2231 eliminate any risk of ASLR bypass due to the vsyscall 2232 fixed address mapping. Attempts to use the vsyscalls 2233 will be reported to dmesg, so that either old or 2234 malicious userspace programs can be identified. 2235 2236endchoice 2237 2238config CMDLINE_BOOL 2239 bool "Built-in kernel command line" 2240 help 2241 Allow for specifying boot arguments to the kernel at 2242 build time. On some systems (e.g. embedded ones), it is 2243 necessary or convenient to provide some or all of the 2244 kernel boot arguments with the kernel itself (that is, 2245 to not rely on the boot loader to provide them.) 2246 2247 To compile command line arguments into the kernel, 2248 set this option to 'Y', then fill in the 2249 boot arguments in CONFIG_CMDLINE. 2250 2251 Systems with fully functional boot loaders (i.e. non-embedded) 2252 should leave this option set to 'N'. 2253 2254config CMDLINE 2255 string "Built-in kernel command string" 2256 depends on CMDLINE_BOOL 2257 default "" 2258 help 2259 Enter arguments here that should be compiled into the kernel 2260 image and used at boot time. If the boot loader provides a 2261 command line at boot time, it is appended to this string to 2262 form the full kernel command line, when the system boots. 2263 2264 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2265 change this behavior. 2266 2267 In most cases, the command line (whether built-in or provided 2268 by the boot loader) should specify the device for the root 2269 file system. 2270 2271config CMDLINE_OVERRIDE 2272 bool "Built-in command line overrides boot loader arguments" 2273 depends on CMDLINE_BOOL && CMDLINE != "" 2274 help 2275 Set this option to 'Y' to have the kernel ignore the boot loader 2276 command line, and use ONLY the built-in command line. 2277 2278 This is used to work around broken boot loaders. This should 2279 be set to 'N' under normal conditions. 2280 2281config MODIFY_LDT_SYSCALL 2282 bool "Enable the LDT (local descriptor table)" if EXPERT 2283 default y 2284 help 2285 Linux can allow user programs to install a per-process x86 2286 Local Descriptor Table (LDT) using the modify_ldt(2) system 2287 call. This is required to run 16-bit or segmented code such as 2288 DOSEMU or some Wine programs. It is also used by some very old 2289 threading libraries. 2290 2291 Enabling this feature adds a small amount of overhead to 2292 context switches and increases the low-level kernel attack 2293 surface. Disabling it removes the modify_ldt(2) system call. 2294 2295 Saying 'N' here may make sense for embedded or server kernels. 2296 2297config STRICT_SIGALTSTACK_SIZE 2298 bool "Enforce strict size checking for sigaltstack" 2299 depends on DYNAMIC_SIGFRAME 2300 help 2301 For historical reasons MINSIGSTKSZ is a constant which became 2302 already too small with AVX512 support. Add a mechanism to 2303 enforce strict checking of the sigaltstack size against the 2304 real size of the FPU frame. This option enables the check 2305 by default. It can also be controlled via the kernel command 2306 line option 'strict_sas_size' independent of this config 2307 switch. Enabling it might break existing applications which 2308 allocate a too small sigaltstack but 'work' because they 2309 never get a signal delivered. 2310 2311 Say 'N' unless you want to really enforce this check. 2312 2313config CFI_AUTO_DEFAULT 2314 bool "Attempt to use FineIBT by default at boot time" 2315 depends on FINEIBT 2316 depends on !RUST || RUSTC_VERSION >= 108800 2317 default y 2318 help 2319 Attempt to use FineIBT by default at boot time. If enabled, 2320 this is the same as booting with "cfi=auto". If disabled, 2321 this is the same as booting with "cfi=kcfi". 2322 2323source "kernel/livepatch/Kconfig" 2324 2325config X86_BUS_LOCK_DETECT 2326 bool "Split Lock Detect and Bus Lock Detect support" 2327 depends on CPU_SUP_INTEL || CPU_SUP_AMD 2328 default y 2329 help 2330 Enable Split Lock Detect and Bus Lock Detect functionalities. 2331 See <file:Documentation/arch/x86/buslock.rst> for more information. 2332 2333endmenu 2334 2335config CC_HAS_NAMED_AS 2336 def_bool $(success,echo 'int __seg_fs fs; int __seg_gs gs;' | $(CC) -x c - -S -o /dev/null) 2337 depends on CC_IS_GCC 2338 2339# 2340# -fsanitize=kernel-address (KASAN) and -fsanitize=thread (KCSAN) 2341# are incompatible with named address spaces with GCC < 13.3 2342# (see GCC PR sanitizer/111736 and also PR sanitizer/115172). 2343# 2344 2345config CC_HAS_NAMED_AS_FIXED_SANITIZERS 2346 def_bool y 2347 depends on !(KASAN || KCSAN) || GCC_VERSION >= 130300 2348 depends on !(UBSAN_BOOL && KASAN) || GCC_VERSION >= 140200 2349 2350config USE_X86_SEG_SUPPORT 2351 def_bool CC_HAS_NAMED_AS 2352 depends on CC_HAS_NAMED_AS_FIXED_SANITIZERS 2353 2354config CC_HAS_SLS 2355 def_bool $(cc-option,-mharden-sls=all) 2356 2357config CC_HAS_RETURN_THUNK 2358 def_bool $(cc-option,-mfunction-return=thunk-extern) 2359 2360config CC_HAS_ENTRY_PADDING 2361 def_bool $(cc-option,-fpatchable-function-entry=16,16) 2362 2363config CC_HAS_KCFI_ARITY 2364 def_bool $(cc-option,-fsanitize=kcfi -fsanitize-kcfi-arity) 2365 depends on CC_IS_CLANG && !RUST 2366 2367config FUNCTION_PADDING_CFI 2368 int 2369 default 59 if FUNCTION_ALIGNMENT_64B 2370 default 27 if FUNCTION_ALIGNMENT_32B 2371 default 11 if FUNCTION_ALIGNMENT_16B 2372 default 3 if FUNCTION_ALIGNMENT_8B 2373 default 0 2374 2375# Basically: FUNCTION_ALIGNMENT - 5*CFI 2376# except Kconfig can't do arithmetic :/ 2377config FUNCTION_PADDING_BYTES 2378 int 2379 default FUNCTION_PADDING_CFI if CFI 2380 default FUNCTION_ALIGNMENT 2381 2382config CALL_PADDING 2383 def_bool n 2384 depends on CC_HAS_ENTRY_PADDING && OBJTOOL 2385 select FUNCTION_ALIGNMENT_16B 2386 2387config FINEIBT 2388 def_bool y 2389 depends on X86_KERNEL_IBT && CFI && MITIGATION_RETPOLINE 2390 select CALL_PADDING 2391 2392config FINEIBT_BHI 2393 def_bool y 2394 depends on FINEIBT && CC_HAS_KCFI_ARITY 2395 2396config HAVE_CALL_THUNKS 2397 def_bool y 2398 depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL 2399 2400config CALL_THUNKS 2401 def_bool n 2402 select CALL_PADDING 2403 2404menuconfig CPU_MITIGATIONS 2405 bool "Mitigations for CPU vulnerabilities" 2406 default y 2407 help 2408 Say Y here to enable options which enable mitigations for hardware 2409 vulnerabilities (usually related to speculative execution). 2410 Mitigations can be disabled or restricted to SMT systems at runtime 2411 via the "mitigations" kernel parameter. 2412 2413 If you say N, all mitigations will be disabled. This CANNOT be 2414 overridden at runtime. 2415 2416 Say 'Y', unless you really know what you are doing. 2417 2418if CPU_MITIGATIONS 2419 2420config MITIGATION_PAGE_TABLE_ISOLATION 2421 bool "Remove the kernel mapping in user mode" 2422 default y 2423 depends on (X86_64 || X86_PAE) 2424 help 2425 This feature reduces the number of hardware side channels by 2426 ensuring that the majority of kernel addresses are not mapped 2427 into userspace. 2428 2429 See Documentation/arch/x86/pti.rst for more details. 2430 2431config MITIGATION_RETPOLINE 2432 bool "Avoid speculative indirect branches in kernel" 2433 select OBJTOOL if HAVE_OBJTOOL 2434 default y 2435 help 2436 Compile kernel with the retpoline compiler options to guard against 2437 kernel-to-user data leaks by avoiding speculative indirect 2438 branches. Requires a compiler with -mindirect-branch=thunk-extern 2439 support for full protection. The kernel may run slower. 2440 2441config MITIGATION_RETHUNK 2442 bool "Enable return-thunks" 2443 depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK 2444 select OBJTOOL if HAVE_OBJTOOL 2445 default y if X86_64 2446 help 2447 Compile the kernel with the return-thunks compiler option to guard 2448 against kernel-to-user data leaks by avoiding return speculation. 2449 Requires a compiler with -mfunction-return=thunk-extern 2450 support for full protection. The kernel may run slower. 2451 2452config MITIGATION_UNRET_ENTRY 2453 bool "Enable UNRET on kernel entry" 2454 depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64 2455 default y 2456 help 2457 Compile the kernel with support for the retbleed=unret mitigation. 2458 2459config MITIGATION_CALL_DEPTH_TRACKING 2460 bool "Mitigate RSB underflow with call depth tracking" 2461 depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS 2462 select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 2463 select CALL_THUNKS 2464 default y 2465 help 2466 Compile the kernel with call depth tracking to mitigate the Intel 2467 SKL Return-Stack-Buffer (RSB) underflow issue. The mitigation is off 2468 by default and needs to be enabled on the kernel command line via the 2469 retbleed=stuff option. For non-affected systems the overhead of this 2470 option is marginal as the call depth tracking is using run-time 2471 generated call thunks in a compiler generated padding area and call 2472 patching. This increases text size by ~5%. For non affected systems 2473 this space is unused. On affected SKL systems this results in a 2474 significant performance gain over the IBRS mitigation. 2475 2476config CALL_THUNKS_DEBUG 2477 bool "Enable call thunks and call depth tracking debugging" 2478 depends on MITIGATION_CALL_DEPTH_TRACKING 2479 select FUNCTION_ALIGNMENT_32B 2480 default n 2481 help 2482 Enable call/ret counters for imbalance detection and build in 2483 a noisy dmesg about callthunks generation and call patching for 2484 trouble shooting. The debug prints need to be enabled on the 2485 kernel command line with 'debug-callthunks'. 2486 Only enable this when you are debugging call thunks as this 2487 creates a noticeable runtime overhead. If unsure say N. 2488 2489config MITIGATION_IBPB_ENTRY 2490 bool "Enable IBPB on kernel entry" 2491 depends on CPU_SUP_AMD && X86_64 2492 default y 2493 help 2494 Compile the kernel with support for the retbleed=ibpb and 2495 spec_rstack_overflow={ibpb,ibpb-vmexit} mitigations. 2496 2497config MITIGATION_IBRS_ENTRY 2498 bool "Enable IBRS on kernel entry" 2499 depends on CPU_SUP_INTEL && X86_64 2500 default y 2501 help 2502 Compile the kernel with support for the spectre_v2=ibrs mitigation. 2503 This mitigates both spectre_v2 and retbleed at great cost to 2504 performance. 2505 2506config MITIGATION_SRSO 2507 bool "Mitigate speculative RAS overflow on AMD" 2508 depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK 2509 default y 2510 help 2511 Enable the SRSO mitigation needed on AMD Zen1-4 machines. 2512 2513config MITIGATION_SLS 2514 bool "Mitigate Straight-Line-Speculation" 2515 depends on CC_HAS_SLS && X86_64 2516 select OBJTOOL if HAVE_OBJTOOL 2517 default n 2518 help 2519 Compile the kernel with straight-line-speculation options to guard 2520 against straight line speculation. The kernel image might be slightly 2521 larger. 2522 2523config MITIGATION_GDS 2524 bool "Mitigate Gather Data Sampling" 2525 depends on CPU_SUP_INTEL 2526 default y 2527 help 2528 Enable mitigation for Gather Data Sampling (GDS). GDS is a hardware 2529 vulnerability which allows unprivileged speculative access to data 2530 which was previously stored in vector registers. The attacker uses gather 2531 instructions to infer the stale vector register data. 2532 2533config MITIGATION_RFDS 2534 bool "RFDS Mitigation" 2535 depends on CPU_SUP_INTEL 2536 default y 2537 help 2538 Enable mitigation for Register File Data Sampling (RFDS) by default. 2539 RFDS is a hardware vulnerability which affects Intel Atom CPUs. It 2540 allows unprivileged speculative access to stale data previously 2541 stored in floating point, vector and integer registers. 2542 See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst> 2543 2544config MITIGATION_SPECTRE_BHI 2545 bool "Mitigate Spectre-BHB (Branch History Injection)" 2546 depends on CPU_SUP_INTEL 2547 default y 2548 help 2549 Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks 2550 where the branch history buffer is poisoned to speculatively steer 2551 indirect branches. 2552 See <file:Documentation/admin-guide/hw-vuln/spectre.rst> 2553 2554config MITIGATION_MDS 2555 bool "Mitigate Microarchitectural Data Sampling (MDS) hardware bug" 2556 depends on CPU_SUP_INTEL 2557 default y 2558 help 2559 Enable mitigation for Microarchitectural Data Sampling (MDS). MDS is 2560 a hardware vulnerability which allows unprivileged speculative access 2561 to data which is available in various CPU internal buffers. 2562 See also <file:Documentation/admin-guide/hw-vuln/mds.rst> 2563 2564config MITIGATION_TAA 2565 bool "Mitigate TSX Asynchronous Abort (TAA) hardware bug" 2566 depends on CPU_SUP_INTEL 2567 default y 2568 help 2569 Enable mitigation for TSX Asynchronous Abort (TAA). TAA is a hardware 2570 vulnerability that allows unprivileged speculative access to data 2571 which is available in various CPU internal buffers by using 2572 asynchronous aborts within an Intel TSX transactional region. 2573 See also <file:Documentation/admin-guide/hw-vuln/tsx_async_abort.rst> 2574 2575config MITIGATION_MMIO_STALE_DATA 2576 bool "Mitigate MMIO Stale Data hardware bug" 2577 depends on CPU_SUP_INTEL 2578 default y 2579 help 2580 Enable mitigation for MMIO Stale Data hardware bugs. Processor MMIO 2581 Stale Data Vulnerabilities are a class of memory-mapped I/O (MMIO) 2582 vulnerabilities that can expose data. The vulnerabilities require the 2583 attacker to have access to MMIO. 2584 See also 2585 <file:Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst> 2586 2587config MITIGATION_L1TF 2588 bool "Mitigate L1 Terminal Fault (L1TF) hardware bug" 2589 depends on CPU_SUP_INTEL 2590 default y 2591 help 2592 Mitigate L1 Terminal Fault (L1TF) hardware bug. L1 Terminal Fault is a 2593 hardware vulnerability which allows unprivileged speculative access to data 2594 available in the Level 1 Data Cache. 2595 See <file:Documentation/admin-guide/hw-vuln/l1tf.rst 2596 2597config MITIGATION_RETBLEED 2598 bool "Mitigate RETBleed hardware bug" 2599 depends on (CPU_SUP_INTEL && MITIGATION_SPECTRE_V2) || MITIGATION_UNRET_ENTRY || MITIGATION_IBPB_ENTRY 2600 default y 2601 help 2602 Enable mitigation for RETBleed (Arbitrary Speculative Code Execution 2603 with Return Instructions) vulnerability. RETBleed is a speculative 2604 execution attack which takes advantage of microarchitectural behavior 2605 in many modern microprocessors, similar to Spectre v2. An 2606 unprivileged attacker can use these flaws to bypass conventional 2607 memory security restrictions to gain read access to privileged memory 2608 that would otherwise be inaccessible. 2609 2610config MITIGATION_SPECTRE_V1 2611 bool "Mitigate SPECTRE V1 hardware bug" 2612 default y 2613 help 2614 Enable mitigation for Spectre V1 (Bounds Check Bypass). Spectre V1 is a 2615 class of side channel attacks that takes advantage of speculative 2616 execution that bypasses conditional branch instructions used for 2617 memory access bounds check. 2618 See also <file:Documentation/admin-guide/hw-vuln/spectre.rst> 2619 2620config MITIGATION_SPECTRE_V2 2621 bool "Mitigate SPECTRE V2 hardware bug" 2622 default y 2623 help 2624 Enable mitigation for Spectre V2 (Branch Target Injection). Spectre 2625 V2 is a class of side channel attacks that takes advantage of 2626 indirect branch predictors inside the processor. In Spectre variant 2 2627 attacks, the attacker can steer speculative indirect branches in the 2628 victim to gadget code by poisoning the branch target buffer of a CPU 2629 used for predicting indirect branch addresses. 2630 See also <file:Documentation/admin-guide/hw-vuln/spectre.rst> 2631 2632config MITIGATION_SRBDS 2633 bool "Mitigate Special Register Buffer Data Sampling (SRBDS) hardware bug" 2634 depends on CPU_SUP_INTEL 2635 default y 2636 help 2637 Enable mitigation for Special Register Buffer Data Sampling (SRBDS). 2638 SRBDS is a hardware vulnerability that allows Microarchitectural Data 2639 Sampling (MDS) techniques to infer values returned from special 2640 register accesses. An unprivileged user can extract values returned 2641 from RDRAND and RDSEED executed on another core or sibling thread 2642 using MDS techniques. 2643 See also 2644 <file:Documentation/admin-guide/hw-vuln/special-register-buffer-data-sampling.rst> 2645 2646config MITIGATION_SSB 2647 bool "Mitigate Speculative Store Bypass (SSB) hardware bug" 2648 default y 2649 help 2650 Enable mitigation for Speculative Store Bypass (SSB). SSB is a 2651 hardware security vulnerability and its exploitation takes advantage 2652 of speculative execution in a similar way to the Meltdown and Spectre 2653 security vulnerabilities. 2654 2655config MITIGATION_ITS 2656 bool "Enable Indirect Target Selection mitigation" 2657 depends on CPU_SUP_INTEL && X86_64 2658 depends on MITIGATION_RETPOLINE && MITIGATION_RETHUNK 2659 select EXECMEM 2660 default y 2661 help 2662 Enable Indirect Target Selection (ITS) mitigation. ITS is a bug in 2663 BPU on some Intel CPUs that may allow Spectre V2 style attacks. If 2664 disabled, mitigation cannot be enabled via cmdline. 2665 See <file:Documentation/admin-guide/hw-vuln/indirect-target-selection.rst> 2666 2667config MITIGATION_TSA 2668 bool "Mitigate Transient Scheduler Attacks" 2669 depends on CPU_SUP_AMD 2670 default y 2671 help 2672 Enable mitigation for Transient Scheduler Attacks. TSA is a hardware 2673 security vulnerability on AMD CPUs which can lead to forwarding of 2674 invalid info to subsequent instructions and thus can affect their 2675 timing and thereby cause a leakage. 2676 2677config MITIGATION_VMSCAPE 2678 bool "Mitigate VMSCAPE" 2679 depends on KVM 2680 default y 2681 help 2682 Enable mitigation for VMSCAPE attacks. VMSCAPE is a hardware security 2683 vulnerability on Intel and AMD CPUs that may allow a guest to do 2684 Spectre v2 style attacks on userspace hypervisor. 2685endif 2686 2687config ARCH_HAS_ADD_PAGES 2688 def_bool y 2689 depends on ARCH_ENABLE_MEMORY_HOTPLUG 2690 2691menu "Power management and ACPI options" 2692 2693config ARCH_HIBERNATION_HEADER 2694 def_bool y 2695 depends on HIBERNATION 2696 2697source "kernel/power/Kconfig" 2698 2699source "drivers/acpi/Kconfig" 2700 2701config X86_APM_BOOT 2702 def_bool y 2703 depends on APM 2704 2705menuconfig APM 2706 tristate "APM (Advanced Power Management) BIOS support" 2707 depends on X86_32 && PM_SLEEP 2708 help 2709 APM is a BIOS specification for saving power using several different 2710 techniques. This is mostly useful for battery powered laptops with 2711 APM compliant BIOSes. If you say Y here, the system time will be 2712 reset after a RESUME operation, the /proc/apm device will provide 2713 battery status information, and user-space programs will receive 2714 notification of APM "events" (e.g. battery status change). 2715 2716 If you select "Y" here, you can disable actual use of the APM 2717 BIOS by passing the "apm=off" option to the kernel at boot time. 2718 2719 Note that the APM support is almost completely disabled for 2720 machines with more than one CPU. 2721 2722 In order to use APM, you will need supporting software. For location 2723 and more information, read <file:Documentation/power/apm-acpi.rst> 2724 and the Battery Powered Linux mini-HOWTO, available from 2725 <http://www.tldp.org/docs.html#howto>. 2726 2727 This driver does not spin down disk drives (see the hdparm(8) 2728 manpage ("man 8 hdparm") for that), and it doesn't turn off 2729 VESA-compliant "green" monitors. 2730 2731 Generally, if you don't have a battery in your machine, there isn't 2732 much point in using this driver and you should say N. If you get 2733 random kernel OOPSes or reboots that don't seem to be related to 2734 anything, try disabling/enabling this option (or disabling/enabling 2735 APM in your BIOS). 2736 2737 Some other things you should try when experiencing seemingly random, 2738 "weird" problems: 2739 2740 1) make sure that you have enough swap space and that it is 2741 enabled. 2742 2) pass the "idle=poll" option to the kernel 2743 3) pass the "floppy=nodma" option to the kernel 2744 4) pass the "mem=4M" option to the kernel (thereby disabling 2745 all but the first 4 MB of RAM) 2746 5) make sure that the CPU is not over clocked. 2747 6) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2748 7) disable the cache from your BIOS settings 2749 8) install a fan for the video card or exchange video RAM 2750 9) install a better fan for the CPU 2751 10) exchange RAM chips 2752 11) exchange the motherboard. 2753 2754 To compile this driver as a module, choose M here: the 2755 module will be called apm. 2756 2757if APM 2758 2759config APM_IGNORE_USER_SUSPEND 2760 bool "Ignore USER SUSPEND" 2761 help 2762 This option will ignore USER SUSPEND requests. On machines with a 2763 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2764 series notebooks, it is necessary to say Y because of a BIOS bug. 2765 2766config APM_DO_ENABLE 2767 bool "Enable PM at boot time" 2768 help 2769 Enable APM features at boot time. From page 36 of the APM BIOS 2770 specification: "When disabled, the APM BIOS does not automatically 2771 power manage devices, enter the Standby State, enter the Suspend 2772 State, or take power saving steps in response to CPU Idle calls." 2773 This driver will make CPU Idle calls when Linux is idle (unless this 2774 feature is turned off -- see "Do CPU IDLE calls", below). This 2775 should always save battery power, but more complicated APM features 2776 will be dependent on your BIOS implementation. You may need to turn 2777 this option off if your computer hangs at boot time when using APM 2778 support, or if it beeps continuously instead of suspending. Turn 2779 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2780 T400CDT. This is off by default since most machines do fine without 2781 this feature. 2782 2783config APM_CPU_IDLE 2784 depends on CPU_IDLE 2785 bool "Make CPU Idle calls when idle" 2786 help 2787 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2788 On some machines, this can activate improved power savings, such as 2789 a slowed CPU clock rate, when the machine is idle. These idle calls 2790 are made after the idle loop has run for some length of time (e.g., 2791 333 mS). On some machines, this will cause a hang at boot time or 2792 whenever the CPU becomes idle. (On machines with more than one CPU, 2793 this option does nothing.) 2794 2795config APM_DISPLAY_BLANK 2796 bool "Enable console blanking using APM" 2797 help 2798 Enable console blanking using the APM. Some laptops can use this to 2799 turn off the LCD backlight when the screen blanker of the Linux 2800 virtual console blanks the screen. Note that this is only used by 2801 the virtual console screen blanker, and won't turn off the backlight 2802 when using the X Window system. This also doesn't have anything to 2803 do with your VESA-compliant power-saving monitor. Further, this 2804 option doesn't work for all laptops -- it might not turn off your 2805 backlight at all, or it might print a lot of errors to the console, 2806 especially if you are using gpm. 2807 2808config APM_ALLOW_INTS 2809 bool "Allow interrupts during APM BIOS calls" 2810 help 2811 Normally we disable external interrupts while we are making calls to 2812 the APM BIOS as a measure to lessen the effects of a badly behaving 2813 BIOS implementation. The BIOS should reenable interrupts if it 2814 needs to. Unfortunately, some BIOSes do not -- especially those in 2815 many of the newer IBM Thinkpads. If you experience hangs when you 2816 suspend, try setting this to Y. Otherwise, say N. 2817 2818endif # APM 2819 2820source "drivers/cpufreq/Kconfig" 2821 2822source "drivers/cpuidle/Kconfig" 2823 2824source "drivers/idle/Kconfig" 2825 2826endmenu 2827 2828menu "Bus options (PCI etc.)" 2829 2830choice 2831 prompt "PCI access mode" 2832 depends on X86_32 && PCI 2833 default PCI_GOANY 2834 help 2835 On PCI systems, the BIOS can be used to detect the PCI devices and 2836 determine their configuration. However, some old PCI motherboards 2837 have BIOS bugs and may crash if this is done. Also, some embedded 2838 PCI-based systems don't have any BIOS at all. Linux can also try to 2839 detect the PCI hardware directly without using the BIOS. 2840 2841 With this option, you can specify how Linux should detect the 2842 PCI devices. If you choose "BIOS", the BIOS will be used, 2843 if you choose "Direct", the BIOS won't be used, and if you 2844 choose "MMConfig", then PCI Express MMCONFIG will be used. 2845 If you choose "Any", the kernel will try MMCONFIG, then the 2846 direct access method and falls back to the BIOS if that doesn't 2847 work. If unsure, go with the default, which is "Any". 2848 2849config PCI_GOBIOS 2850 bool "BIOS" 2851 2852config PCI_GOMMCONFIG 2853 bool "MMConfig" 2854 2855config PCI_GODIRECT 2856 bool "Direct" 2857 2858config PCI_GOOLPC 2859 bool "OLPC XO-1" 2860 depends on OLPC 2861 2862config PCI_GOANY 2863 bool "Any" 2864 2865endchoice 2866 2867config PCI_BIOS 2868 def_bool y 2869 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2870 2871# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2872config PCI_DIRECT 2873 def_bool y 2874 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2875 2876config PCI_MMCONFIG 2877 bool "Support mmconfig PCI config space access" if X86_64 2878 default y 2879 depends on PCI && (ACPI || JAILHOUSE_GUEST) 2880 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2881 help 2882 Add support for accessing the PCI configuration space as a memory 2883 mapped area. It is the recommended method if the system supports 2884 this (it must have PCI Express and ACPI for it to be available). 2885 2886 In the unlikely case that enabling this configuration option causes 2887 problems, the mechanism can be switched off with the 'pci=nommconf' 2888 command line parameter. 2889 2890 Say N only if you are sure that your platform does not support this 2891 access method or you have problems caused by it. 2892 2893 Say Y otherwise. 2894 2895config PCI_OLPC 2896 def_bool y 2897 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2898 2899config PCI_XEN 2900 def_bool y 2901 depends on PCI && XEN 2902 2903config MMCONF_FAM10H 2904 def_bool y 2905 depends on X86_64 && PCI_MMCONFIG && ACPI 2906 2907config PCI_CNB20LE_QUIRK 2908 bool "Read PCI host bridge windows from the CNB20LE chipset" if EXPERT 2909 depends on X86_32 && PCI 2910 help 2911 Read the PCI windows out of the CNB20LE host bridge. This allows 2912 PCI hotplug to work on systems with the CNB20LE chipset which do 2913 not have ACPI. 2914 2915 The ServerWorks (later Broadcom) CNB20LE was a chipset designed 2916 most probably only for Pentium III. 2917 2918 To find out if you have such a chipset, search for a PCI device with 2919 1166:0009 PCI IDs, for example by executing 2920 lspci -nn | grep '1166:0009' 2921 The code is inactive if there is none. 2922 2923 There's no public spec for this chipset, and this functionality 2924 is known to be incomplete. 2925 2926 You should say N unless you know you need this. 2927 2928config ISA_BUS 2929 bool "ISA bus support on modern systems" if EXPERT 2930 help 2931 Expose ISA bus device drivers and options available for selection and 2932 configuration. Enable this option if your target machine has an ISA 2933 bus. ISA is an older system, displaced by PCI and newer bus 2934 architectures -- if your target machine is modern, it probably does 2935 not have an ISA bus. 2936 2937 If unsure, say N. 2938 2939# x86_64 have no ISA slots, but can have ISA-style DMA. 2940config ISA_DMA_API 2941 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2942 default y 2943 help 2944 Enables ISA-style DMA support for devices requiring such controllers. 2945 If unsure, say Y. 2946 2947if X86_32 2948 2949config ISA 2950 bool "ISA support" 2951 help 2952 Find out whether you have ISA slots on your motherboard. ISA is the 2953 name of a bus system, i.e. the way the CPU talks to the other stuff 2954 inside your box. Other bus systems are PCI, EISA, MicroChannel 2955 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2956 newer boards don't support it. If you have ISA, say Y, otherwise N. 2957 2958config SCx200 2959 tristate "NatSemi SCx200 support" 2960 help 2961 This provides basic support for National Semiconductor's 2962 (now AMD's) Geode processors. The driver probes for the 2963 PCI-IDs of several on-chip devices, so its a good dependency 2964 for other scx200_* drivers. 2965 2966 If compiled as a module, the driver is named scx200. 2967 2968config SCx200HR_TIMER 2969 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2970 depends on SCx200 2971 default y 2972 help 2973 This driver provides a clocksource built upon the on-chip 2974 27MHz high-resolution timer. Its also a workaround for 2975 NSC Geode SC-1100's buggy TSC, which loses time when the 2976 processor goes idle (as is done by the scheduler). The 2977 other workaround is idle=poll boot option. 2978 2979config OLPC 2980 bool "One Laptop Per Child support" 2981 depends on !X86_PAE 2982 select GPIOLIB 2983 select GPIOLIB_LEGACY 2984 select OF 2985 select OF_PROMTREE 2986 select IRQ_DOMAIN 2987 select OLPC_EC 2988 help 2989 Add support for detecting the unique features of the OLPC 2990 XO hardware. 2991 2992config OLPC_XO1_PM 2993 bool "OLPC XO-1 Power Management" 2994 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2995 help 2996 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2997 2998config OLPC_XO1_RTC 2999 bool "OLPC XO-1 Real Time Clock" 3000 depends on OLPC_XO1_PM && RTC_DRV_CMOS 3001 help 3002 Add support for the XO-1 real time clock, which can be used as a 3003 programmable wakeup source. 3004 3005config OLPC_XO1_SCI 3006 bool "OLPC XO-1 SCI extras" 3007 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 3008 depends on INPUT=y 3009 select POWER_SUPPLY 3010 help 3011 Add support for SCI-based features of the OLPC XO-1 laptop: 3012 - EC-driven system wakeups 3013 - Power button 3014 - Ebook switch 3015 - Lid switch 3016 - AC adapter status updates 3017 - Battery status updates 3018 3019config OLPC_XO15_SCI 3020 bool "OLPC XO-1.5 SCI extras" 3021 depends on OLPC && ACPI 3022 select POWER_SUPPLY 3023 help 3024 Add support for SCI-based features of the OLPC XO-1.5 laptop: 3025 - EC-driven system wakeups 3026 - AC adapter status updates 3027 - Battery status updates 3028 3029config GEODE_COMMON 3030 bool 3031 3032config ALIX 3033 bool "PCEngines ALIX System Support (LED setup)" 3034 depends on GPIO_CS5535=y 3035 select GEODE_COMMON 3036 help 3037 This option enables system support for the PCEngines ALIX. 3038 At present this just sets up LEDs for GPIO control on 3039 ALIX2/3/6 boards. However, other system specific setup should 3040 get added here. 3041 3042 Note: You must still enable the drivers for LED support (LEDS_GPIO) 3043 to actually use the LEDs 3044 3045 Note: You have to set alix.force=1 for boards with Award BIOS. 3046 3047config NET5501 3048 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 3049 depends on GPIO_CS5535=y 3050 select GEODE_COMMON 3051 help 3052 This option enables system support for the Soekris Engineering net5501. 3053 3054config GEOS 3055 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 3056 depends on GPIO_CS5535=y 3057 select GEODE_COMMON 3058 depends on DMI 3059 help 3060 This option enables system support for the Traverse Technologies GEOS. 3061 3062config TS5500 3063 bool "Technologic Systems TS-5500 platform support" 3064 depends on MELAN 3065 select CHECK_SIGNATURE 3066 select NEW_LEDS 3067 select LEDS_CLASS 3068 help 3069 This option enables system support for the Technologic Systems TS-5500. 3070 3071endif # X86_32 3072 3073config AMD_NB 3074 def_bool y 3075 depends on AMD_NODE 3076 3077config AMD_NODE 3078 def_bool y 3079 depends on CPU_SUP_AMD && PCI 3080 3081endmenu 3082 3083menu "Binary Emulations" 3084 3085config IA32_EMULATION 3086 bool "IA32 Emulation" 3087 depends on X86_64 3088 select ARCH_WANT_OLD_COMPAT_IPC 3089 select BINFMT_ELF 3090 select COMPAT_OLD_SIGACTION 3091 help 3092 Include code to run legacy 32-bit programs under a 3093 64-bit kernel. You should likely turn this on, unless you're 3094 100% sure that you don't have any 32-bit programs left. 3095 3096config IA32_EMULATION_DEFAULT_DISABLED 3097 bool "IA32 emulation disabled by default" 3098 default n 3099 depends on IA32_EMULATION 3100 help 3101 Make IA32 emulation disabled by default. This prevents loading 32-bit 3102 processes and access to 32-bit syscalls. If unsure, leave it to its 3103 default value. 3104 3105config X86_X32_ABI 3106 bool "x32 ABI for 64-bit mode" 3107 depends on X86_64 3108 # llvm-objcopy does not convert x86_64 .note.gnu.property or 3109 # compressed debug sections to x86_x32 properly: 3110 # https://github.com/ClangBuiltLinux/linux/issues/514 3111 # https://github.com/ClangBuiltLinux/linux/issues/1141 3112 depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm) 3113 help 3114 Include code to run binaries for the x32 native 32-bit ABI 3115 for 64-bit processors. An x32 process gets access to the 3116 full 64-bit register file and wide data path while leaving 3117 pointers at 32 bits for smaller memory footprint. 3118 3119config COMPAT_32 3120 def_bool y 3121 depends on IA32_EMULATION || X86_32 3122 select HAVE_UID16 3123 select OLD_SIGSUSPEND3 3124 3125config COMPAT 3126 def_bool y 3127 depends on IA32_EMULATION || X86_X32_ABI 3128 3129config COMPAT_FOR_U64_ALIGNMENT 3130 def_bool y 3131 depends on COMPAT 3132 3133endmenu 3134 3135config HAVE_ATOMIC_IOMAP 3136 def_bool y 3137 depends on X86_32 3138 3139source "arch/x86/kvm/Kconfig" 3140 3141source "arch/x86/Kconfig.cpufeatures" 3142 3143source "arch/x86/Kconfig.assembler" 3144