1# SPDX-License-Identifier: GPL-2.0 2# Select 32 or 64 bit 3config 64BIT 4 bool "64-bit kernel" if "$(ARCH)" = "x86" 5 default "$(ARCH)" != "i386" 6 help 7 Say yes to build a 64-bit kernel - formerly known as x86_64 8 Say no to build a 32-bit kernel - formerly known as i386 9 10config X86_32 11 def_bool y 12 depends on !64BIT 13 # Options that are inherently 32-bit kernel only: 14 select ARCH_WANT_IPC_PARSE_VERSION 15 select CLKSRC_I8253 16 select CLONE_BACKWARDS 17 select HAVE_DEBUG_STACKOVERFLOW 18 select KMAP_LOCAL 19 select MODULES_USE_ELF_REL 20 select OLD_SIGACTION 21 select ARCH_SPLIT_ARG64 22 23config X86_64 24 def_bool y 25 depends on 64BIT 26 # Options that are inherently 64-bit kernel only: 27 select ARCH_HAS_GIGANTIC_PAGE 28 select ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS 29 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 30 select ARCH_SUPPORTS_PER_VMA_LOCK 31 select ARCH_SUPPORTS_HUGE_PFNMAP if TRANSPARENT_HUGEPAGE 32 select HAVE_ARCH_SOFT_DIRTY 33 select MODULES_USE_ELF_RELA 34 select NEED_DMA_MAP_STATE 35 select SWIOTLB 36 select ARCH_HAS_ELFCORE_COMPAT 37 select ZONE_DMA32 38 select EXECMEM if DYNAMIC_FTRACE 39 select ACPI_MRRM if ACPI 40 41config FORCE_DYNAMIC_FTRACE 42 def_bool y 43 depends on X86_32 44 depends on FUNCTION_TRACER 45 select DYNAMIC_FTRACE 46 help 47 We keep the static function tracing (!DYNAMIC_FTRACE) around 48 in order to test the non static function tracing in the 49 generic code, as other architectures still use it. But we 50 only need to keep it around for x86_64. No need to keep it 51 for x86_32. For x86_32, force DYNAMIC_FTRACE. 52# 53# Arch settings 54# 55# ( Note that options that are marked 'if X86_64' could in principle be 56# ported to 32-bit as well. ) 57# 58config X86 59 def_bool y 60 # 61 # Note: keep this list sorted alphabetically 62 # 63 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 64 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 65 select ACPI_HOTPLUG_CPU if ACPI_PROCESSOR && HOTPLUG_CPU 66 select ARCH_32BIT_OFF_T if X86_32 67 select ARCH_CLOCKSOURCE_INIT 68 select ARCH_CONFIGURES_CPU_MITIGATIONS 69 select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 70 select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION 71 select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64 72 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE) 73 select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE 74 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 75 select ARCH_HAS_CPU_ATTACK_VECTORS if CPU_MITIGATIONS 76 select ARCH_HAS_CACHE_LINE_SIZE 77 select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION 78 select ARCH_HAS_CPU_FINALIZE_INIT 79 select ARCH_HAS_CPU_PASID if IOMMU_SVA 80 select ARCH_HAS_CURRENT_STACK_POINTER 81 select ARCH_HAS_DEBUG_VIRTUAL 82 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 83 select ARCH_HAS_DEVMEM_IS_ALLOWED 84 select ARCH_HAS_DMA_OPS if GART_IOMMU || XEN 85 select ARCH_HAS_EARLY_DEBUG if KGDB 86 select ARCH_HAS_ELF_RANDOMIZE 87 select ARCH_HAS_EXECMEM_ROX if X86_64 && STRICT_MODULE_RWX 88 select ARCH_HAS_FAST_MULTIPLIER 89 select ARCH_HAS_FORTIFY_SOURCE 90 select ARCH_HAS_GCOV_PROFILE_ALL 91 select ARCH_HAS_KCOV if X86_64 92 select ARCH_HAS_KERNEL_FPU_SUPPORT 93 select ARCH_HAS_MEM_ENCRYPT 94 select ARCH_HAS_MEMBARRIER_SYNC_CORE 95 select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS 96 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 97 select ARCH_HAS_PMEM_API if X86_64 98 select ARCH_HAS_PREEMPT_LAZY 99 select ARCH_HAS_PTDUMP 100 select ARCH_HAS_PTE_SPECIAL 101 select ARCH_HAS_HW_PTE_YOUNG 102 select ARCH_HAS_NONLEAF_PMD_YOUNG if PGTABLE_LEVELS > 2 103 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 104 select ARCH_HAS_COPY_MC if X86_64 105 select ARCH_HAS_SET_MEMORY 106 select ARCH_HAS_SET_DIRECT_MAP 107 select ARCH_HAS_STRICT_KERNEL_RWX 108 select ARCH_HAS_STRICT_MODULE_RWX 109 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 110 select ARCH_HAS_SYSCALL_WRAPPER 111 select ARCH_HAS_UBSAN 112 select ARCH_HAS_DEBUG_WX 113 select ARCH_HAS_ZONE_DMA_SET if EXPERT 114 select ARCH_HAVE_NMI_SAFE_CMPXCHG 115 select ARCH_HAVE_EXTRA_ELF_NOTES 116 select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 117 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 118 select ARCH_MIGHT_HAVE_PC_PARPORT 119 select ARCH_MIGHT_HAVE_PC_SERIO 120 select ARCH_STACKWALK 121 select ARCH_SUPPORTS_ACPI 122 select ARCH_SUPPORTS_ATOMIC_RMW 123 select ARCH_SUPPORTS_DEBUG_PAGEALLOC 124 select ARCH_SUPPORTS_HUGETLBFS 125 select ARCH_SUPPORTS_PAGE_TABLE_CHECK if X86_64 126 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 127 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 128 select ARCH_SUPPORTS_CFI if X86_64 129 select ARCH_USES_CFI_TRAPS if X86_64 && CFI 130 select ARCH_SUPPORTS_LTO_CLANG 131 select ARCH_SUPPORTS_LTO_CLANG_THIN 132 select ARCH_SUPPORTS_RT 133 select ARCH_SUPPORTS_AUTOFDO_CLANG 134 select ARCH_SUPPORTS_PROPELLER_CLANG if X86_64 135 select ARCH_USE_BUILTIN_BSWAP 136 select ARCH_USE_CMPXCHG_LOCKREF if X86_CX8 137 select ARCH_USE_MEMTEST 138 select ARCH_USE_QUEUED_RWLOCKS 139 select ARCH_USE_QUEUED_SPINLOCKS 140 select ARCH_USE_SYM_ANNOTATIONS 141 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 142 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 143 select ARCH_WANTS_CLOCKSOURCE_READ_INLINE if X86_64 144 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 145 select ARCH_WANTS_NO_INSTR 146 select ARCH_WANT_GENERAL_HUGETLB 147 select ARCH_WANT_HUGE_PMD_SHARE if X86_64 148 select ARCH_WANT_LD_ORPHAN_WARN 149 select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP if X86_64 150 select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP if X86_64 151 select ARCH_WANT_HUGETLB_VMEMMAP_PREINIT if X86_64 152 select ARCH_WANTS_THP_SWAP if X86_64 153 select ARCH_HAS_PARANOID_L1D_FLUSH 154 select ARCH_WANT_IRQS_OFF_ACTIVATE_MM 155 select BUILDTIME_TABLE_SORT 156 select CLKEVT_I8253 157 select CLOCKSOURCE_WATCHDOG 158 # Word-size accesses may read uninitialized data past the trailing \0 159 # in strings and cause false KMSAN reports. 160 select DCACHE_WORD_ACCESS if !KMSAN 161 select DYNAMIC_SIGFRAME 162 select EDAC_ATOMIC_SCRUB 163 select EDAC_SUPPORT 164 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 165 select GENERIC_CLOCKEVENTS_BROADCAST_IDLE if GENERIC_CLOCKEVENTS_BROADCAST 166 select GENERIC_CLOCKEVENTS_COUPLED_INLINE if X86_64 167 select GENERIC_CLOCKEVENTS_MIN_ADJUST 168 select GENERIC_CMOS_UPDATE 169 select GENERIC_CPU_AUTOPROBE 170 select GENERIC_CPU_DEVICES 171 select GENERIC_CPU_VULNERABILITIES 172 select GENERIC_EARLY_IOREMAP 173 select GENERIC_ENTRY 174 select GENERIC_IOMAP 175 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 176 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 177 select GENERIC_IRQ_MIGRATION if SMP 178 select GENERIC_IRQ_PROBE 179 select GENERIC_IRQ_RESERVATION_MODE 180 select GENERIC_IRQ_SHOW 181 select GENERIC_PENDING_IRQ if SMP 182 select GENERIC_SMP_IDLE_THREAD 183 select GENERIC_TIME_VSYSCALL 184 select GENERIC_GETTIMEOFDAY 185 select GENERIC_VDSO_OVERFLOW_PROTECT 186 select GUP_GET_PXX_LOW_HIGH if X86_PAE 187 select HARDIRQS_SW_RESEND 188 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 189 select HAS_IOPORT 190 select HAVE_ACPI_APEI if ACPI 191 select HAVE_ACPI_APEI_NMI if ACPI 192 select HAVE_ALIGNED_STRUCT_PAGE 193 select HAVE_ARCH_AUDITSYSCALL 194 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 195 select HAVE_ARCH_HUGE_VMALLOC if X86_64 196 select HAVE_ARCH_JUMP_LABEL 197 select HAVE_ARCH_JUMP_LABEL_RELATIVE 198 select HAVE_ARCH_KASAN if X86_64 199 select HAVE_ARCH_KASAN_VMALLOC if X86_64 200 select HAVE_ARCH_KFENCE 201 select HAVE_ARCH_KMSAN if X86_64 202 select HAVE_ARCH_KGDB 203 select HAVE_ARCH_KSTACK_ERASE 204 select HAVE_ARCH_MMAP_RND_BITS if MMU 205 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 206 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 207 select HAVE_ARCH_PREL32_RELOCATIONS 208 select HAVE_ARCH_SECCOMP_FILTER 209 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 210 select HAVE_ARCH_TRACEHOOK 211 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 212 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 213 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 214 select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 215 select HAVE_ARCH_VMAP_STACK if X86_64 216 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 217 select HAVE_ARCH_WITHIN_STACK_FRAMES 218 select HAVE_ASM_MODVERSIONS 219 select HAVE_CMPXCHG_DOUBLE 220 select HAVE_CMPXCHG_LOCAL 221 select HAVE_CONTEXT_TRACKING_USER if X86_64 222 select HAVE_CONTEXT_TRACKING_USER_OFFSTACK if HAVE_CONTEXT_TRACKING_USER 223 select HAVE_C_RECORDMCOUNT 224 select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL 225 select HAVE_OBJTOOL_NOP_MCOUNT if HAVE_OBJTOOL_MCOUNT 226 select HAVE_BUILDTIME_MCOUNT_SORT 227 select HAVE_DEBUG_KMEMLEAK 228 select HAVE_DMA_CONTIGUOUS 229 select HAVE_DYNAMIC_FTRACE 230 select HAVE_DYNAMIC_FTRACE_WITH_REGS 231 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 232 select HAVE_FTRACE_REGS_HAVING_PT_REGS if X86_64 233 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 234 select HAVE_DYNAMIC_FTRACE_WITH_JMP if X86_64 235 select HAVE_SAMPLE_FTRACE_DIRECT if X86_64 236 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64 237 select HAVE_EBPF_JIT 238 select HAVE_EFFICIENT_UNALIGNED_ACCESS 239 select HAVE_EISA if X86_32 240 select HAVE_EXIT_THREAD 241 select HAVE_GENERIC_TIF_BITS 242 select HAVE_GUP_FAST 243 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 244 select HAVE_FTRACE_GRAPH_FUNC if HAVE_FUNCTION_GRAPH_TRACER 245 select HAVE_FUNCTION_GRAPH_FREGS if HAVE_FUNCTION_GRAPH_TRACER 246 select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) 247 select HAVE_FUNCTION_TRACER 248 select HAVE_GCC_PLUGINS 249 select HAVE_HW_BREAKPOINT 250 select HAVE_IOREMAP_PROT 251 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 252 select HAVE_IRQ_TIME_ACCOUNTING 253 select HAVE_JUMP_LABEL_HACK if HAVE_OBJTOOL 254 select HAVE_KERNEL_BZIP2 255 select HAVE_KERNEL_GZIP 256 select HAVE_KERNEL_LZ4 257 select HAVE_KERNEL_LZMA 258 select HAVE_KERNEL_LZO 259 select HAVE_KERNEL_XZ 260 select HAVE_KERNEL_ZSTD 261 select HAVE_KPROBES 262 select HAVE_KPROBES_ON_FTRACE 263 select HAVE_FUNCTION_ERROR_INJECTION 264 select HAVE_KRETPROBES 265 select HAVE_RETHOOK 266 select HAVE_KLP_BUILD if X86_64 267 select HAVE_LIVEPATCH if X86_64 268 select HAVE_MIXED_BREAKPOINTS_REGS 269 select HAVE_MOD_ARCH_SPECIFIC 270 select HAVE_MOVE_PMD 271 select HAVE_MOVE_PUD 272 select HAVE_NOINSTR_HACK if HAVE_OBJTOOL 273 select HAVE_NMI 274 select HAVE_NOINSTR_VALIDATION if HAVE_OBJTOOL 275 select HAVE_OBJTOOL if X86_64 276 select HAVE_OPTPROBES 277 select HAVE_PAGE_SIZE_4KB 278 select HAVE_PCSPKR_PLATFORM 279 select HAVE_PERF_EVENTS 280 select HAVE_PERF_EVENTS_NMI 281 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 282 select HAVE_PCI 283 select HAVE_PERF_REGS 284 select HAVE_PERF_USER_STACK_DUMP 285 select ASYNC_KERNEL_PGTABLE_FREE if IOMMU_SVA 286 select MMU_GATHER_RCU_TABLE_FREE 287 select MMU_GATHER_MERGE_VMAS 288 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 289 select HAVE_REGS_AND_STACK_ACCESS_API 290 select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC || STACK_VALIDATION 291 select HAVE_FUNCTION_ARG_ACCESS_API 292 select HAVE_SETUP_PER_CPU_AREA 293 select HAVE_SOFTIRQ_ON_OWN_STACK 294 select HAVE_STACKPROTECTOR 295 select HAVE_STACK_VALIDATION if HAVE_OBJTOOL 296 select HAVE_STATIC_CALL 297 select HAVE_STATIC_CALL_INLINE if HAVE_OBJTOOL 298 select HAVE_PREEMPT_DYNAMIC_CALL 299 select HAVE_RSEQ 300 select HAVE_RUST if X86_64 301 select HAVE_SYSCALL_TRACEPOINTS 302 select HAVE_UACCESS_VALIDATION if HAVE_OBJTOOL 303 select HAVE_UNSTABLE_SCHED_CLOCK 304 select HAVE_UNWIND_USER_FP if X86_64 305 select HAVE_USER_RETURN_NOTIFIER 306 select HAVE_GENERIC_VDSO 307 select VDSO_GETRANDOM if X86_64 308 select HOTPLUG_PARALLEL if SMP && X86_64 309 select HOTPLUG_SMT if SMP 310 select HOTPLUG_SPLIT_STARTUP if SMP && X86_32 311 select IRQ_FORCED_THREADING 312 select LOCK_MM_AND_FIND_VMA 313 select NEED_PER_CPU_EMBED_FIRST_CHUNK 314 select NEED_PER_CPU_PAGE_FIRST_CHUNK 315 select NEED_SG_DMA_LENGTH 316 select NUMA_MEMBLKS if NUMA 317 select PCI_DOMAINS if PCI 318 select PCI_LOCKLESS_CONFIG if PCI 319 select PERF_EVENTS 320 select RTC_LIB 321 select RTC_MC146818_LIB 322 select SPARSE_IRQ 323 select SYSCTL_EXCEPTION_TRACE 324 select THREAD_INFO_IN_TASK 325 select TRACE_IRQFLAGS_SUPPORT 326 select TRACE_IRQFLAGS_NMI_SUPPORT 327 select USER_STACKTRACE_SUPPORT 328 select HAVE_ARCH_KCSAN if X86_64 329 select PROC_PID_ARCH_STATUS if PROC_FS 330 select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX 331 select FUNCTION_ALIGNMENT_16B if X86_64 || X86_ALIGNMENT_16 332 select FUNCTION_ALIGNMENT_4B 333 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 334 select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 335 select ARCH_SUPPORTS_SCHED_SMT if SMP 336 select SCHED_SMT if SMP 337 select ARCH_SUPPORTS_SCHED_CLUSTER if SMP 338 select ARCH_SUPPORTS_SCHED_MC if SMP 339 select HAVE_SINGLE_FTRACE_DIRECT_OPS if X86_64 && DYNAMIC_FTRACE_WITH_DIRECT_CALLS 340 341config INSTRUCTION_DECODER 342 def_bool y 343 depends on KPROBES || PERF_EVENTS || UPROBES 344 345config OUTPUT_FORMAT 346 string 347 default "elf32-i386" if X86_32 348 default "elf64-x86-64" if X86_64 349 350config LOCKDEP_SUPPORT 351 def_bool y 352 353config STACKTRACE_SUPPORT 354 def_bool y 355 356config MMU 357 def_bool y 358 359config ARCH_MMAP_RND_BITS_MIN 360 default 28 if 64BIT 361 default 8 362 363config ARCH_MMAP_RND_BITS_MAX 364 default 32 if 64BIT 365 default 16 366 367config ARCH_MMAP_RND_COMPAT_BITS_MIN 368 default 8 369 370config ARCH_MMAP_RND_COMPAT_BITS_MAX 371 default 16 372 373config SBUS 374 bool 375 376config GENERIC_ISA_DMA 377 def_bool y 378 depends on ISA_DMA_API 379 380config GENERIC_CSUM 381 bool 382 default y if KMSAN || KASAN 383 384config GENERIC_BUG 385 def_bool y 386 depends on BUG 387 select GENERIC_BUG_RELATIVE_POINTERS 388 389config GENERIC_BUG_RELATIVE_POINTERS 390 bool 391 392config ARCH_MAY_HAVE_PC_FDC 393 def_bool y 394 depends on ISA_DMA_API 395 396config GENERIC_CALIBRATE_DELAY 397 def_bool y 398 399config ARCH_HAS_CPU_RELAX 400 def_bool y 401 402config ARCH_HIBERNATION_POSSIBLE 403 def_bool y 404 405config ARCH_SUSPEND_POSSIBLE 406 def_bool y 407 408config AUDIT_ARCH 409 def_bool y if X86_64 410 411config KASAN_SHADOW_OFFSET 412 hex 413 depends on KASAN 414 default 0xdffffc0000000000 415 416config HAVE_INTEL_TXT 417 def_bool y 418 depends on INTEL_IOMMU && ACPI 419 420config ARCH_SUPPORTS_UPROBES 421 def_bool y 422 423config FIX_EARLYCON_MEM 424 def_bool y 425 426config DYNAMIC_PHYSICAL_MASK 427 bool 428 429config PGTABLE_LEVELS 430 int 431 default 5 if X86_64 432 default 3 if X86_PAE 433 default 2 434 435menu "Processor type and features" 436 437config SMP 438 bool "Symmetric multi-processing support" 439 help 440 This enables support for systems with more than one CPU. If you have 441 a system with only one CPU, say N. If you have a system with more 442 than one CPU, say Y. 443 444 If you say N here, the kernel will run on uni- and multiprocessor 445 machines, but will use only one CPU of a multiprocessor machine. If 446 you say Y here, the kernel will run on many, but not all, 447 uniprocessor machines. On a uniprocessor machine, the kernel 448 will run faster if you say N here. 449 450 People using multiprocessor machines who say Y here should also say 451 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 452 Management" code will be disabled if you say Y here. 453 454 See also <file:Documentation/arch/x86/i386/IO-APIC.rst>, 455 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 456 <http://www.tldp.org/docs.html#howto>. 457 458 If you don't know what to do here, say N. 459 460config X86_X2APIC 461 bool "x2APIC interrupt controller architecture support" 462 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 463 default y 464 help 465 x2APIC is an interrupt controller architecture, a component of which 466 (the local APIC) is present in the CPU. It allows faster access to 467 the local APIC and supports a larger number of CPUs in the system 468 than the predecessors. 469 470 x2APIC was introduced in Intel CPUs around 2008 and in AMD EPYC CPUs 471 in 2019, but it can be disabled by the BIOS. It is also frequently 472 emulated in virtual machines, even when the host CPU does not support 473 it. Support in the CPU can be checked by executing 474 grep x2apic /proc/cpuinfo 475 476 If this configuration option is disabled, the kernel will boot with 477 very reduced functionality and performance on some platforms that 478 have x2APIC enabled. On the other hand, on hardware that does not 479 support x2APIC, a kernel with this option enabled will just fallback 480 to older APIC implementations. 481 482 If in doubt, say Y. 483 484config AMD_SECURE_AVIC 485 bool "AMD Secure AVIC" 486 depends on AMD_MEM_ENCRYPT && X86_X2APIC 487 help 488 Enable this to get AMD Secure AVIC support on guests that have this feature. 489 490 AMD Secure AVIC provides hardware acceleration for performance sensitive 491 APIC accesses and support for managing guest owned APIC state for SEV-SNP 492 guests. Secure AVIC does not support xAPIC mode. It has functional 493 dependency on x2apic being enabled in the guest. 494 495 If you don't know what to do here, say N. 496 497config X86_POSTED_MSI 498 bool "Enable MSI and MSI-x delivery by posted interrupts" 499 depends on X86_64 && IRQ_REMAP 500 help 501 This enables MSIs that are under interrupt remapping to be delivered as 502 posted interrupts to the host kernel. Interrupt throughput can 503 potentially be improved by coalescing CPU notifications during high 504 frequency bursts. 505 506 If you don't know what to do here, say N. 507 508config X86_MPPARSE 509 bool "Enable MPS table" if ACPI 510 default y 511 depends on X86_LOCAL_APIC 512 help 513 For old smp systems that do not have proper acpi support. Newer systems 514 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 515 516config X86_CPU_RESCTRL 517 bool "x86 CPU resource control support" 518 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 519 depends on MISC_FILESYSTEMS 520 select ARCH_HAS_CPU_RESCTRL 521 select RESCTRL_FS 522 select RESCTRL_FS_PSEUDO_LOCK 523 help 524 Enable x86 CPU resource control support. 525 526 Provide support for the allocation and monitoring of system resources 527 usage by the CPU. 528 529 Intel calls this Intel Resource Director Technology 530 (Intel(R) RDT). More information about RDT can be found in the 531 Intel x86 Architecture Software Developer Manual. 532 533 AMD calls this AMD Platform Quality of Service (AMD QoS). 534 More information about AMD QoS can be found in the AMD64 Technology 535 Platform Quality of Service Extensions manual. 536 537 Say N if unsure. 538 539config X86_CPU_RESCTRL_INTEL_AET 540 bool "Intel Application Energy Telemetry" 541 depends on X86_64 && X86_CPU_RESCTRL && CPU_SUP_INTEL && INTEL_PMT_TELEMETRY=y && INTEL_TPMI=y 542 help 543 Enable per-RMID telemetry events in resctrl. 544 545 Intel feature that collects per-RMID execution data 546 about energy consumption, measure of frequency independent 547 activity and other performance metrics. Data is aggregated 548 per package. 549 550 Say N if unsure. 551 552config X86_FRED 553 bool "Flexible Return and Event Delivery" 554 depends on X86_64 555 help 556 When enabled, use Flexible Return and Event Delivery 557 instead of the legacy SYSCALL/SYSENTER/IDT architecture for 558 ring transitions and exception/interrupt handling if the 559 system supports it. 560 561config X86_EXTENDED_PLATFORM 562 bool "Support for extended (non-PC) x86 platforms" 563 default y 564 help 565 If you disable this option then the kernel will only support 566 standard PC platforms. (which covers the vast majority of 567 systems out there.) 568 569 If you enable this option then you'll be able to select support 570 for the following non-PC x86 platforms, depending on the value of 571 CONFIG_64BIT. 572 573 32-bit platforms (CONFIG_64BIT=n): 574 Goldfish (mostly Android emulator) 575 Intel CE media processor (CE4100) SoC 576 Intel Quark 577 RDC R-321x SoC 578 579 64-bit platforms (CONFIG_64BIT=y): 580 Numascale NumaChip 581 ScaleMP vSMP 582 SGI Ultraviolet 583 Merrifield/Moorefield MID devices 584 Goldfish (mostly Android emulator) 585 586 If you have one of these systems, or if you want to build a 587 generic distribution kernel, say Y here - otherwise say N. 588 589# This is an alphabetically sorted list of 64 bit extended platforms 590# Please maintain the alphabetic order if and when there are additions 591config X86_NUMACHIP 592 bool "Numascale NumaChip" 593 depends on X86_64 594 depends on X86_EXTENDED_PLATFORM 595 depends on NUMA 596 depends on SMP 597 depends on X86_X2APIC 598 depends on PCI_MMCONFIG 599 help 600 Adds support for Numascale NumaChip large-SMP systems. Needed to 601 enable more than ~168 cores. 602 If you don't have one of these, you should say N here. 603 604config X86_VSMP 605 bool "ScaleMP vSMP" 606 select HYPERVISOR_GUEST 607 select PARAVIRT 608 depends on X86_64 && PCI 609 depends on X86_EXTENDED_PLATFORM 610 depends on SMP 611 help 612 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 613 supposed to run on these EM64T-based machines. Only choose this option 614 if you have one of these machines. 615 616config X86_UV 617 bool "SGI Ultraviolet" 618 depends on X86_64 619 depends on X86_EXTENDED_PLATFORM 620 depends on NUMA 621 depends on EFI 622 depends on KEXEC_CORE 623 depends on X86_X2APIC 624 depends on PCI 625 help 626 This option is needed in order to support SGI Ultraviolet systems. 627 If you don't have one of these, you should say N here. 628 629config X86_INTEL_MID 630 bool "Intel Z34xx/Z35xx MID platform support" 631 depends on X86_EXTENDED_PLATFORM 632 depends on X86_PLATFORM_DEVICES 633 depends on PCI 634 depends on X86_64 || (EXPERT && PCI_GOANY) 635 depends on X86_IO_APIC 636 select I2C 637 select DW_APB_TIMER 638 select INTEL_SCU_PCI 639 help 640 Select to build a kernel capable of supporting 64-bit Intel MID 641 (Mobile Internet Device) platform systems which do not have 642 the PCI legacy interfaces. 643 644 The only supported devices are the 22nm Merrified (Z34xx) 645 and Moorefield (Z35xx) SoC used in the Intel Edison board and 646 a small number of Android devices such as the Asus Zenfone 2, 647 Asus FonePad 8 and Dell Venue 7. 648 649 If you are building for a PC class system or non-MID tablet 650 SoCs like Bay Trail (Z36xx/Z37xx), say N here. 651 652 Intel MID platforms are based on an Intel processor and chipset which 653 consume less power than most of the x86 derivatives. 654 655config X86_GOLDFISH 656 bool "Goldfish (Virtual Platform)" 657 depends on X86_EXTENDED_PLATFORM 658 help 659 Enable support for the Goldfish virtual platform used primarily 660 for Android development. Unless you are building for the Android 661 Goldfish emulator say N here. 662 663# Following is an alphabetically sorted list of 32 bit extended platforms 664# Please maintain the alphabetic order if and when there are additions 665 666config X86_INTEL_CE 667 bool "CE4100 TV platform" 668 depends on PCI 669 depends on PCI_GODIRECT 670 depends on X86_IO_APIC 671 depends on X86_32 672 depends on X86_EXTENDED_PLATFORM 673 select X86_REBOOTFIXUPS 674 select OF 675 select OF_EARLY_FLATTREE 676 help 677 Select for the Intel CE media processor (CE4100) SOC. 678 This option compiles in support for the CE4100 SOC for settop 679 boxes and media devices. 680 681config X86_INTEL_QUARK 682 bool "Intel Quark platform support" 683 depends on X86_32 684 depends on X86_EXTENDED_PLATFORM 685 depends on X86_PLATFORM_DEVICES 686 depends on X86_TSC 687 depends on PCI 688 depends on PCI_GOANY 689 depends on X86_IO_APIC 690 select IOSF_MBI 691 select INTEL_IMR 692 select COMMON_CLK 693 help 694 Select to include support for Quark X1000 SoC. 695 Say Y here if you have a Quark based system such as the Arduino 696 compatible Intel Galileo. 697 698config X86_INTEL_LPSS 699 bool "Intel Low Power Subsystem Support" 700 depends on X86 && ACPI && PCI 701 select COMMON_CLK 702 select PINCTRL 703 select IOSF_MBI 704 help 705 Select to build support for Intel Low Power Subsystem such as 706 found on Intel Lynxpoint PCH. Selecting this option enables 707 things like clock tree (common clock framework) and pincontrol 708 which are needed by the LPSS peripheral drivers. 709 710config X86_AMD_PLATFORM_DEVICE 711 bool "AMD ACPI2Platform devices support" 712 depends on ACPI 713 select COMMON_CLK 714 select PINCTRL 715 help 716 Select to interpret AMD specific ACPI device to platform device 717 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 718 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 719 implemented under PINCTRL subsystem. 720 721config IOSF_MBI 722 tristate "Intel SoC IOSF Sideband support for SoC platforms" 723 depends on PCI 724 help 725 This option enables sideband register access support for Intel SoC 726 platforms. On these platforms the IOSF sideband is used in lieu of 727 MSR's for some register accesses, mostly but not limited to thermal 728 and power. Drivers may query the availability of this device to 729 determine if they need the sideband in order to work on these 730 platforms. The sideband is available on the following SoC products. 731 This list is not meant to be exclusive. 732 - BayTrail 733 - Braswell 734 - Quark 735 736 You should say Y if you are running a kernel on one of these SoC's. 737 738config IOSF_MBI_DEBUG 739 bool "Enable IOSF sideband access through debugfs" 740 depends on IOSF_MBI && DEBUG_FS 741 help 742 Select this option to expose the IOSF sideband access registers (MCR, 743 MDR, MCRX) through debugfs to write and read register information from 744 different units on the SoC. This is most useful for obtaining device 745 state information for debug and analysis. As this is a general access 746 mechanism, users of this option would have specific knowledge of the 747 device they want to access. 748 749 If you don't require the option or are in doubt, say N. 750 751config X86_SUPPORTS_MEMORY_FAILURE 752 def_bool y 753 # MCE code calls memory_failure(): 754 depends on X86_MCE 755 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 756 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 757 depends on X86_64 || !SPARSEMEM 758 select ARCH_SUPPORTS_MEMORY_FAILURE 759 760config X86_32_IRIS 761 tristate "Eurobraille/Iris poweroff module" 762 depends on X86_32 763 help 764 The Iris machines from EuroBraille do not have APM or ACPI support 765 to shut themselves down properly. A special I/O sequence is 766 needed to do so, which is what this module does at 767 kernel shutdown. 768 769 This is only for Iris machines from EuroBraille. 770 771 If unused, say N. 772 773config SCHED_OMIT_FRAME_POINTER 774 def_bool y 775 prompt "Single-depth WCHAN output" 776 depends on X86 777 help 778 Calculate simpler /proc/<PID>/wchan values. If this option 779 is disabled then wchan values will recurse back to the 780 caller function. This provides more accurate wchan values, 781 at the expense of slightly more scheduling overhead. 782 783 If in doubt, say "Y". 784 785menuconfig HYPERVISOR_GUEST 786 bool "Linux guest support" 787 help 788 Say Y here to enable options for running Linux under various hyper- 789 visors. This option enables basic hypervisor detection and platform 790 setup. 791 792 If you say N, all options in this submenu will be skipped and 793 disabled, and Linux guest support won't be built in. 794 795if HYPERVISOR_GUEST 796 797config PARAVIRT 798 bool "Enable paravirtualization code" 799 depends on HAVE_STATIC_CALL 800 select HAVE_PV_STEAL_CLOCK_GEN 801 help 802 This changes the kernel so it can modify itself when it is run 803 under a hypervisor, potentially improving performance significantly 804 over full virtualization. However, when run without a hypervisor 805 the kernel is theoretically slower and slightly larger. 806 807config PARAVIRT_XXL 808 bool 809 depends on X86_64 810 select ARCH_HAS_LAZY_MMU_MODE 811 812config PARAVIRT_SPINLOCKS 813 bool "Paravirtualization layer for spinlocks" 814 depends on PARAVIRT && SMP 815 help 816 Paravirtualized spinlocks allow a pvops backend to replace the 817 spinlock implementation with something virtualization-friendly 818 (for example, block the virtual CPU rather than spinning). 819 820 It has a minimal impact on native kernels and gives a nice performance 821 benefit on paravirtualized KVM / Xen kernels. 822 823 If you are unsure how to answer this question, answer Y. 824 825config X86_HV_CALLBACK_VECTOR 826 def_bool n 827 828source "arch/x86/xen/Kconfig" 829 830config KVM_GUEST 831 bool "KVM Guest support (including kvmclock)" 832 depends on PARAVIRT 833 select PARAVIRT_CLOCK 834 select ARCH_CPUIDLE_HALTPOLL 835 select X86_HV_CALLBACK_VECTOR 836 default y 837 help 838 This option enables various optimizations for running under the KVM 839 hypervisor. It includes a paravirtualized clock, so that instead 840 of relying on a PIT (or probably other) emulation by the 841 underlying device model, the host provides the guest with 842 timing infrastructure such as time of day, and system time 843 844config ARCH_CPUIDLE_HALTPOLL 845 def_bool n 846 prompt "Disable host haltpoll when loading haltpoll driver" 847 help 848 If virtualized under KVM, disable host haltpoll. 849 850config PVH 851 bool "Support for running PVH guests" 852 help 853 This option enables the PVH entry point for guest virtual machines 854 as specified in the x86/HVM direct boot ABI. 855 856config PARAVIRT_TIME_ACCOUNTING 857 bool "Paravirtual steal time accounting" 858 depends on PARAVIRT 859 help 860 Select this option to enable fine granularity task steal time 861 accounting. Time spent executing other tasks in parallel with 862 the current vCPU is discounted from the vCPU power. To account for 863 that, there can be a small performance impact. 864 865 If in doubt, say N here. 866 867config PARAVIRT_CLOCK 868 bool 869 870config JAILHOUSE_GUEST 871 bool "Jailhouse non-root cell support" 872 depends on X86_64 && PCI 873 select X86_PM_TIMER 874 help 875 This option allows to run Linux as guest in a Jailhouse non-root 876 cell. You can leave this option disabled if you only want to start 877 Jailhouse and run Linux afterwards in the root cell. 878 879config ACRN_GUEST 880 bool "ACRN Guest support" 881 depends on X86_64 882 select X86_HV_CALLBACK_VECTOR 883 help 884 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 885 a flexible, lightweight reference open-source hypervisor, built with 886 real-time and safety-criticality in mind. It is built for embedded 887 IOT with small footprint and real-time features. More details can be 888 found in https://projectacrn.org/. 889 890config BHYVE_GUEST 891 bool "Bhyve (BSD Hypervisor) Guest support" 892 depends on X86_64 893 help 894 This option allows to run Linux to recognise when it is running as a 895 guest in the Bhyve hypervisor, and to support more than 255 vCPUs when 896 when doing so. More details about Bhyve can be found at https://bhyve.org 897 and https://wiki.freebsd.org/bhyve/. 898 899config INTEL_TDX_GUEST 900 bool "Intel TDX (Trust Domain Extensions) - Guest Support" 901 depends on X86_64 && CPU_SUP_INTEL 902 depends on X86_X2APIC 903 depends on EFI_STUB 904 depends on PARAVIRT 905 select ARCH_HAS_CC_PLATFORM 906 select X86_MEM_ENCRYPT 907 select X86_MCE 908 select UNACCEPTED_MEMORY 909 help 910 Support running as a guest under Intel TDX. Without this support, 911 the guest kernel can not boot or run under TDX. 912 TDX includes memory encryption and integrity capabilities 913 which protect the confidentiality and integrity of guest 914 memory contents and CPU state. TDX guests are protected from 915 some attacks from the VMM. 916 917endif # HYPERVISOR_GUEST 918 919source "arch/x86/Kconfig.cpu" 920 921config HPET_TIMER 922 def_bool X86_64 923 prompt "HPET Timer Support" if X86_32 924 help 925 Use the IA-PC HPET (High Precision Event Timer) to manage 926 time in preference to the PIT and RTC, if a HPET is 927 present. 928 HPET is the next generation timer replacing legacy 8254s. 929 The HPET provides a stable time base on SMP 930 systems, unlike the TSC, but it is more expensive to access, 931 as it is off-chip. The interface used is documented 932 in the HPET spec, revision 1. 933 934 You can safely choose Y here. However, HPET will only be 935 activated if the platform and the BIOS support this feature. 936 Otherwise the 8254 will be used for timing services. 937 938 Choose N to continue using the legacy 8254 timer. 939 940config HPET_EMULATE_RTC 941 def_bool y 942 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 943 944# Mark as expert because too many people got it wrong. 945# The code disables itself when not needed. 946config DMI 947 default y 948 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 949 bool "Enable DMI scanning" if EXPERT 950 help 951 Enabled scanning of DMI to identify machine quirks. Say Y 952 here unless you have verified that your setup is not 953 affected by entries in the DMI blacklist. Required by PNP 954 BIOS code. 955 956config GART_IOMMU 957 bool "Old AMD GART IOMMU support" 958 select IOMMU_HELPER 959 select SWIOTLB 960 depends on X86_64 && PCI && AMD_NB 961 help 962 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 963 GART based hardware IOMMUs. 964 965 The GART supports full DMA access for devices with 32-bit access 966 limitations, on systems with more than 3 GB. This is usually needed 967 for USB, sound, many IDE/SATA chipsets and some other devices. 968 969 Newer systems typically have a modern AMD IOMMU, supported via 970 the CONFIG_AMD_IOMMU=y config option. 971 972 In normal configurations this driver is only active when needed: 973 there's more than 3 GB of memory and the system contains a 974 32-bit limited device. 975 976 If unsure, say Y. 977 978config BOOT_VESA_SUPPORT 979 bool 980 help 981 If true, at least one selected framebuffer driver can take advantage 982 of VESA video modes set at an early boot stage via the vga= parameter. 983 984config MAXSMP 985 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 986 depends on X86_64 && SMP && DEBUG_KERNEL 987 select CPUMASK_OFFSTACK 988 help 989 Enable maximum number of CPUS and NUMA Nodes for this architecture. 990 If unsure, say N. 991 992# 993# The maximum number of CPUs supported: 994# 995# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 996# and which can be configured interactively in the 997# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 998# 999# The ranges are different on 32-bit and 64-bit kernels, depending on 1000# hardware capabilities and scalability features of the kernel. 1001# 1002# ( If MAXSMP is enabled we just use the highest possible value and disable 1003# interactive configuration. ) 1004# 1005 1006config NR_CPUS_RANGE_BEGIN 1007 int 1008 default NR_CPUS_RANGE_END if MAXSMP 1009 default 1 if !SMP 1010 default 2 1011 1012config NR_CPUS_RANGE_END 1013 int 1014 depends on X86_32 1015 default 8 if SMP 1016 default 1 if !SMP 1017 1018config NR_CPUS_RANGE_END 1019 int 1020 depends on X86_64 1021 default 8192 if SMP && CPUMASK_OFFSTACK 1022 default 512 if SMP && !CPUMASK_OFFSTACK 1023 default 1 if !SMP 1024 1025config NR_CPUS_DEFAULT 1026 int 1027 depends on X86_32 1028 default 8 if SMP 1029 default 1 if !SMP 1030 1031config NR_CPUS_DEFAULT 1032 int 1033 depends on X86_64 1034 default 8192 if MAXSMP 1035 default 64 if SMP 1036 default 1 if !SMP 1037 1038config NR_CPUS 1039 int "Maximum number of CPUs" if SMP && !MAXSMP 1040 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1041 default NR_CPUS_DEFAULT 1042 help 1043 This allows you to specify the maximum number of CPUs which this 1044 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1045 supported value is 8192, otherwise the maximum value is 512. The 1046 minimum value which makes sense is 2. 1047 1048 This is purely to save memory: each supported CPU adds about 8KB 1049 to the kernel image. 1050 1051config SCHED_MC_PRIO 1052 bool "CPU core priorities scheduler support" 1053 depends on SCHED_MC 1054 select X86_INTEL_PSTATE if CPU_SUP_INTEL 1055 select X86_AMD_PSTATE if CPU_SUP_AMD && ACPI 1056 select CPU_FREQ 1057 default y 1058 help 1059 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1060 core ordering determined at manufacturing time, which allows 1061 certain cores to reach higher turbo frequencies (when running 1062 single threaded workloads) than others. 1063 1064 Enabling this kernel feature teaches the scheduler about 1065 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1066 scheduler's CPU selection logic accordingly, so that higher 1067 overall system performance can be achieved. 1068 1069 This feature will have no effect on CPUs without this feature. 1070 1071 If unsure say Y here. 1072 1073config UP_LATE_INIT 1074 def_bool y 1075 depends on !SMP && X86_LOCAL_APIC 1076 1077config X86_UP_APIC 1078 bool "Local APIC support on uniprocessors" if !PCI_MSI 1079 default PCI_MSI 1080 depends on X86_32 && !SMP 1081 help 1082 A local APIC (Advanced Programmable Interrupt Controller) is an 1083 integrated interrupt controller in the CPU. If you have a single-CPU 1084 system which has a processor with a local APIC, you can say Y here to 1085 enable and use it. If you say Y here even though your machine doesn't 1086 have a local APIC, then the kernel will still run with no slowdown at 1087 all. The local APIC supports CPU-generated self-interrupts (timer, 1088 performance counters), and the NMI watchdog which detects hard 1089 lockups. 1090 1091config X86_UP_IOAPIC 1092 bool "IO-APIC support on uniprocessors" 1093 depends on X86_UP_APIC 1094 help 1095 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1096 SMP-capable replacement for PC-style interrupt controllers. Most 1097 SMP systems and many recent uniprocessor systems have one. 1098 1099 If you have a single-CPU system with an IO-APIC, you can say Y here 1100 to use it. If you say Y here even though your machine doesn't have 1101 an IO-APIC, then the kernel will still run with no slowdown at all. 1102 1103config X86_LOCAL_APIC 1104 def_bool y 1105 depends on X86_64 || SMP || X86_UP_APIC || PCI_MSI 1106 select IRQ_DOMAIN_HIERARCHY 1107 1108config ACPI_MADT_WAKEUP 1109 def_bool y 1110 depends on X86_64 1111 depends on ACPI 1112 depends on SMP 1113 depends on X86_LOCAL_APIC 1114 1115config X86_IO_APIC 1116 def_bool y 1117 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1118 1119config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1120 bool "Reroute for broken boot IRQs" 1121 depends on X86_IO_APIC 1122 help 1123 This option enables a workaround that fixes a source of 1124 spurious interrupts. This is recommended when threaded 1125 interrupt handling is used on systems where the generation of 1126 superfluous "boot interrupts" cannot be disabled. 1127 1128 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1129 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1130 kernel does during interrupt handling). On chipsets where this 1131 boot IRQ generation cannot be disabled, this workaround keeps 1132 the original IRQ line masked so that only the equivalent "boot 1133 IRQ" is delivered to the CPUs. The workaround also tells the 1134 kernel to set up the IRQ handler on the boot IRQ line. In this 1135 way only one interrupt is delivered to the kernel. Otherwise 1136 the spurious second interrupt may cause the kernel to bring 1137 down (vital) interrupt lines. 1138 1139 Only affects "broken" chipsets. Interrupt sharing may be 1140 increased on these systems. 1141 1142config X86_MCE 1143 bool "Machine Check / overheating reporting" 1144 select GENERIC_ALLOCATOR 1145 default y 1146 help 1147 Machine Check support allows the processor to notify the 1148 kernel if it detects a problem (e.g. overheating, data corruption). 1149 The action the kernel takes depends on the severity of the problem, 1150 ranging from warning messages to halting the machine. 1151 1152config X86_MCELOG_LEGACY 1153 bool "Support for deprecated /dev/mcelog character device" 1154 depends on X86_MCE 1155 help 1156 Enable support for /dev/mcelog which is needed by the old mcelog 1157 userspace logging daemon. Consider switching to the new generation 1158 rasdaemon solution. 1159 1160config X86_MCE_INTEL 1161 def_bool y 1162 prompt "Intel MCE features" 1163 depends on X86_MCE && X86_LOCAL_APIC 1164 help 1165 Additional support for intel specific MCE features such as 1166 the thermal monitor. 1167 1168config X86_MCE_AMD 1169 def_bool y 1170 prompt "AMD MCE features" 1171 depends on X86_MCE && X86_LOCAL_APIC 1172 help 1173 Additional support for AMD specific MCE features such as 1174 the DRAM Error Threshold. 1175 1176config X86_ANCIENT_MCE 1177 bool "Support for old Pentium 5 / WinChip machine checks" 1178 depends on X86_32 && X86_MCE 1179 help 1180 Include support for machine check handling on old Pentium 5 or WinChip 1181 systems. These typically need to be enabled explicitly on the command 1182 line. 1183 1184config X86_MCE_THRESHOLD 1185 depends on X86_MCE_AMD || X86_MCE_INTEL 1186 def_bool y 1187 1188config X86_MCE_INJECT 1189 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1190 tristate "Machine check injector support" 1191 help 1192 Provide support for injecting machine checks for testing purposes. 1193 If you don't know what a machine check is and you don't do kernel 1194 QA it is safe to say n. 1195 1196source "arch/x86/events/Kconfig" 1197 1198config X86_LEGACY_VM86 1199 bool "Legacy VM86 support" 1200 depends on X86_32 1201 help 1202 This option allows user programs to put the CPU into V8086 1203 mode, which is an 80286-era approximation of 16-bit real mode. 1204 1205 Some very old versions of X and/or vbetool require this option 1206 for user mode setting. Similarly, DOSEMU will use it if 1207 available to accelerate real mode DOS programs. However, any 1208 recent version of DOSEMU, X, or vbetool should be fully 1209 functional even without kernel VM86 support, as they will all 1210 fall back to software emulation. Nevertheless, if you are using 1211 a 16-bit DOS program where 16-bit performance matters, vm86 1212 mode might be faster than emulation and you might want to 1213 enable this option. 1214 1215 Note that any app that works on a 64-bit kernel is unlikely to 1216 need this option, as 64-bit kernels don't, and can't, support 1217 V8086 mode. This option is also unrelated to 16-bit protected 1218 mode and is not needed to run most 16-bit programs under Wine. 1219 1220 Enabling this option increases the complexity of the kernel 1221 and slows down exception handling a tiny bit. 1222 1223 If unsure, say N here. 1224 1225config VM86 1226 bool 1227 default X86_LEGACY_VM86 1228 1229config X86_16BIT 1230 bool "Enable support for 16-bit segments" if EXPERT 1231 default y 1232 depends on MODIFY_LDT_SYSCALL 1233 help 1234 This option is required by programs like Wine to run 16-bit 1235 protected mode legacy code on x86 processors. Disabling 1236 this option saves about 300 bytes on i386, or around 6K text 1237 plus 16K runtime memory on x86-64, 1238 1239config X86_ESPFIX32 1240 def_bool y 1241 depends on X86_16BIT && X86_32 1242 1243config X86_ESPFIX64 1244 def_bool y 1245 depends on X86_16BIT && X86_64 1246 1247config X86_VSYSCALL_EMULATION 1248 bool "Enable vsyscall emulation" if EXPERT 1249 default y 1250 depends on X86_64 1251 help 1252 This enables emulation of the legacy vsyscall page. Disabling 1253 it is roughly equivalent to booting with vsyscall=none, except 1254 that it will also disable the helpful warning if a program 1255 tries to use a vsyscall. With this option set to N, offending 1256 programs will just segfault, citing addresses of the form 1257 0xffffffffff600?00. 1258 1259 This option is required by many programs built before 2013, and 1260 care should be used even with newer programs if set to N. 1261 1262 Disabling this option saves about 7K of kernel size and 1263 possibly 4K of additional runtime pagetable memory. 1264 1265config X86_IOPL_IOPERM 1266 bool "IOPERM and IOPL Emulation" 1267 default y 1268 help 1269 This enables the ioperm() and iopl() syscalls which are necessary 1270 for legacy applications. 1271 1272 Legacy IOPL support is an overbroad mechanism which allows user 1273 space aside of accessing all 65536 I/O ports also to disable 1274 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1275 capabilities and permission from potentially active security 1276 modules. 1277 1278 The emulation restricts the functionality of the syscall to 1279 only allowing the full range I/O port access, but prevents the 1280 ability to disable interrupts from user space which would be 1281 granted if the hardware IOPL mechanism would be used. 1282 1283config TOSHIBA 1284 tristate "Toshiba Laptop support" 1285 depends on X86_32 1286 help 1287 This adds a driver to safely access the System Management Mode of 1288 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1289 not work on models with a Phoenix BIOS. The System Management Mode 1290 is used to set the BIOS and power saving options on Toshiba portables. 1291 1292 For information on utilities to make use of this driver see the 1293 Toshiba Linux utilities web site at: 1294 <http://www.buzzard.org.uk/toshiba/>. 1295 1296 Say Y if you intend to run this kernel on a Toshiba portable. 1297 Say N otherwise. 1298 1299config X86_REBOOTFIXUPS 1300 bool "Enable X86 board specific fixups for reboot" 1301 depends on X86_32 1302 help 1303 This enables chipset and/or board specific fixups to be done 1304 in order to get reboot to work correctly. This is only needed on 1305 some combinations of hardware and BIOS. The symptom, for which 1306 this config is intended, is when reboot ends with a stalled/hung 1307 system. 1308 1309 Currently, the only fixup is for the Geode machines using 1310 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1311 1312 Say Y if you want to enable the fixup. Currently, it's safe to 1313 enable this option even if you don't need it. 1314 Say N otherwise. 1315 1316config MICROCODE 1317 def_bool y 1318 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1319 select CRYPTO_LIB_SHA256 if CPU_SUP_AMD 1320 1321config MICROCODE_INITRD32 1322 def_bool y 1323 depends on MICROCODE && X86_32 && BLK_DEV_INITRD 1324 1325config MICROCODE_LATE_LOADING 1326 bool "Late microcode loading (DANGEROUS)" 1327 default n 1328 depends on MICROCODE && SMP 1329 help 1330 Loading microcode late, when the system is up and executing instructions 1331 is a tricky business and should be avoided if possible. Just the sequence 1332 of synchronizing all cores and SMT threads is one fragile dance which does 1333 not guarantee that cores might not softlock after the loading. Therefore, 1334 use this at your own risk. Late loading taints the kernel unless the 1335 microcode header indicates that it is safe for late loading via the 1336 minimal revision check. This minimal revision check can be enforced on 1337 the kernel command line with "microcode=force_minrev". 1338 1339config MICROCODE_LATE_FORCE_MINREV 1340 bool "Enforce late microcode loading minimal revision check" 1341 default n 1342 depends on MICROCODE_LATE_LOADING 1343 help 1344 To prevent that users load microcode late which modifies already 1345 in use features, newer microcode patches have a minimum revision field 1346 in the microcode header, which tells the kernel which minimum 1347 revision must be active in the CPU to safely load that new microcode 1348 late into the running system. If disabled the check will not 1349 be enforced but the kernel will be tainted when the minimal 1350 revision check fails. 1351 1352 This minimal revision check can also be controlled via the 1353 "microcode=force_minrev" parameter on the kernel command line. 1354 1355 If unsure say Y. 1356 1357config MICROCODE_DBG 1358 bool "Enable microcode loader debugging" 1359 default n 1360 depends on MICROCODE 1361 help 1362 Enable code which allows to debug the microcode loader. When running 1363 in a guest the patch loading is simulated but everything else 1364 related to patch parsing and handling is done as on baremetal with 1365 the purpose of debugging solely the software side of things. On 1366 baremetal, it simply dumps additional debugging information during 1367 normal operation. 1368 1369 You almost certainly want to say n here. 1370 1371config X86_MSR 1372 tristate "/dev/cpu/*/msr - Model-specific register support" 1373 help 1374 This device gives privileged processes access to the x86 1375 Model-Specific Registers (MSRs). It is a character device with 1376 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1377 MSR accesses are directed to a specific CPU on multi-processor 1378 systems. 1379 1380config X86_CPUID 1381 tristate "/dev/cpu/*/cpuid - CPU information support" 1382 help 1383 This device gives processes access to the x86 CPUID instruction to 1384 be executed on a specific processor. It is a character device 1385 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1386 /dev/cpu/31/cpuid. 1387 1388config HIGHMEM4G 1389 bool "High Memory Support" 1390 depends on X86_32 1391 help 1392 Linux can use up to 4 Gigabytes of physical memory on x86 systems. 1393 However, the address space of 32-bit x86 processors is only 4 1394 Gigabytes large. That means that, if you have a large amount of 1395 physical memory, not all of it can be "permanently mapped" by the 1396 kernel. The physical memory that's not permanently mapped is called 1397 "high memory". 1398 1399 If you are compiling a kernel which will never run on a machine with 1400 more than 1 Gigabyte total physical RAM, answer "off" here (default 1401 choice and suitable for most users). This will result in a "3GB/1GB" 1402 split: 3GB are mapped so that each process sees a 3GB virtual memory 1403 space and the remaining part of the 4GB virtual memory space is used 1404 by the kernel to permanently map as much physical memory as 1405 possible. 1406 1407 If the machine has between 1 and 4 Gigabytes physical RAM, then 1408 answer "Y" here. 1409 1410 If unsure, say N. 1411 1412choice 1413 prompt "Memory split" if EXPERT 1414 default VMSPLIT_3G 1415 depends on X86_32 1416 help 1417 Select the desired split between kernel and user memory. 1418 1419 If the address range available to the kernel is less than the 1420 physical memory installed, the remaining memory will be available 1421 as "high memory". Accessing high memory is a little more costly 1422 than low memory, as it needs to be mapped into the kernel first. 1423 Note that increasing the kernel address space limits the range 1424 available to user programs, making the address space there 1425 tighter. Selecting anything other than the default 3G/1G split 1426 will also likely make your kernel incompatible with binary-only 1427 kernel modules. 1428 1429 If you are not absolutely sure what you are doing, leave this 1430 option alone! 1431 1432 config VMSPLIT_3G 1433 bool "3G/1G user/kernel split" 1434 config VMSPLIT_3G_OPT 1435 depends on !X86_PAE 1436 bool "3G/1G user/kernel split (for full 1G low memory)" 1437 config VMSPLIT_2G 1438 bool "2G/2G user/kernel split" 1439 config VMSPLIT_2G_OPT 1440 depends on !X86_PAE 1441 bool "2G/2G user/kernel split (for full 2G low memory)" 1442 config VMSPLIT_1G 1443 bool "1G/3G user/kernel split" 1444endchoice 1445 1446config PAGE_OFFSET 1447 hex 1448 default 0xB0000000 if VMSPLIT_3G_OPT 1449 default 0x80000000 if VMSPLIT_2G 1450 default 0x78000000 if VMSPLIT_2G_OPT 1451 default 0x40000000 if VMSPLIT_1G 1452 default 0xC0000000 1453 depends on X86_32 1454 1455config HIGHMEM 1456 def_bool HIGHMEM4G 1457 1458config X86_PAE 1459 bool "PAE (Physical Address Extension) Support" 1460 depends on X86_32 && X86_HAVE_PAE 1461 select PHYS_ADDR_T_64BIT 1462 help 1463 PAE is required for NX support, and furthermore enables 1464 larger swapspace support for non-overcommit purposes. It 1465 has the cost of more pagetable lookup overhead, and also 1466 consumes more pagetable space per process. 1467 1468config X86_DIRECT_GBPAGES 1469 def_bool y 1470 depends on X86_64 1471 help 1472 Certain kernel features effectively disable kernel 1473 linear 1 GB mappings (even if the CPU otherwise 1474 supports them), so don't confuse the user by printing 1475 that we have them enabled. 1476 1477config X86_CPA_STATISTICS 1478 bool "Enable statistic for Change Page Attribute" 1479 depends on DEBUG_FS 1480 help 1481 Expose statistics about the Change Page Attribute mechanism, which 1482 helps to determine the effectiveness of preserving large and huge 1483 page mappings when mapping protections are changed. 1484 1485config X86_MEM_ENCRYPT 1486 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1487 select DYNAMIC_PHYSICAL_MASK 1488 def_bool n 1489 1490config AMD_MEM_ENCRYPT 1491 bool "AMD Secure Memory Encryption (SME) support" 1492 depends on X86_64 && CPU_SUP_AMD 1493 depends on EFI_STUB 1494 select DMA_COHERENT_POOL 1495 select ARCH_USE_MEMREMAP_PROT 1496 select INSTRUCTION_DECODER 1497 select ARCH_HAS_CC_PLATFORM 1498 select X86_MEM_ENCRYPT 1499 select UNACCEPTED_MEMORY 1500 select CRYPTO_LIB_AESGCM 1501 help 1502 Say yes to enable support for the encryption of system memory. 1503 This requires an AMD processor that supports Secure Memory 1504 Encryption (SME). 1505 1506# Common NUMA Features 1507config NUMA 1508 bool "NUMA Memory Allocation and Scheduler Support" 1509 depends on SMP 1510 depends on X86_64 1511 select USE_PERCPU_NUMA_NODE_ID 1512 select OF_NUMA if OF 1513 help 1514 Enable NUMA (Non-Uniform Memory Access) support. 1515 1516 The kernel will try to allocate memory used by a CPU on the 1517 local memory controller of the CPU and add some more 1518 NUMA awareness to the kernel. 1519 1520 For 64-bit this is recommended if the system is Intel Core i7 1521 (or later), AMD Opteron, or EM64T NUMA. 1522 1523 Otherwise, you should say N. 1524 1525config AMD_NUMA 1526 def_bool y 1527 prompt "Old style AMD Opteron NUMA detection" 1528 depends on X86_64 && NUMA && PCI 1529 help 1530 Enable AMD NUMA node topology detection. You should say Y here if 1531 you have a multi processor AMD system. This uses an old method to 1532 read the NUMA configuration directly from the builtin Northbridge 1533 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1534 which also takes priority if both are compiled in. 1535 1536config X86_64_ACPI_NUMA 1537 def_bool y 1538 prompt "ACPI NUMA detection" 1539 depends on X86_64 && NUMA && ACPI && PCI 1540 select ACPI_NUMA 1541 help 1542 Enable ACPI SRAT based node topology detection. 1543 1544config NODES_SHIFT 1545 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1546 range 1 10 1547 default "10" if MAXSMP 1548 default "6" if X86_64 1549 default "3" 1550 depends on NUMA 1551 help 1552 Specify the maximum number of NUMA Nodes available on the target 1553 system. Increases memory reserved to accommodate various tables. 1554 1555config ARCH_FLATMEM_ENABLE 1556 def_bool y 1557 depends on X86_32 && !NUMA 1558 1559config ARCH_SPARSEMEM_ENABLE 1560 def_bool y 1561 select SPARSEMEM_STATIC if X86_32 1562 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1563 1564config ARCH_SPARSEMEM_DEFAULT 1565 def_bool X86_64 || (NUMA && X86_32) 1566 1567config ARCH_SELECT_MEMORY_MODEL 1568 def_bool y 1569 depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE 1570 1571config ARCH_MEMORY_PROBE 1572 bool "Enable sysfs memory/probe interface" 1573 depends on MEMORY_HOTPLUG 1574 help 1575 This option enables a sysfs memory/probe interface for testing. 1576 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1577 If you are unsure how to answer this question, answer N. 1578 1579config ARCH_PROC_KCORE_TEXT 1580 def_bool y 1581 depends on X86_64 && PROC_KCORE 1582 1583config ILLEGAL_POINTER_VALUE 1584 hex 1585 default 0 if X86_32 1586 default 0xdead000000000000 if X86_64 1587 1588config X86_PMEM_LEGACY_DEVICE 1589 bool 1590 1591config X86_PMEM_LEGACY 1592 tristate "Support non-standard NVDIMMs and ADR protected memory" 1593 depends on PHYS_ADDR_T_64BIT 1594 depends on BLK_DEV 1595 select X86_PMEM_LEGACY_DEVICE 1596 select NUMA_KEEP_MEMINFO if NUMA 1597 select LIBNVDIMM 1598 help 1599 Treat memory marked using the non-standard e820 type of 12 as used 1600 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1601 The kernel will offer these regions to the 'pmem' driver so 1602 they can be used for persistent storage. 1603 1604 Say Y if unsure. 1605 1606config X86_CHECK_BIOS_CORRUPTION 1607 bool "Check for low memory corruption" 1608 help 1609 Periodically check for memory corruption in low memory, which 1610 is suspected to be caused by BIOS. Even when enabled in the 1611 configuration, it is disabled at runtime. Enable it by 1612 setting "memory_corruption_check=1" on the kernel command 1613 line. By default it scans the low 64k of memory every 60 1614 seconds; see the memory_corruption_check_size and 1615 memory_corruption_check_period parameters in 1616 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1617 1618 When enabled with the default parameters, this option has 1619 almost no overhead, as it reserves a relatively small amount 1620 of memory and scans it infrequently. It both detects corruption 1621 and prevents it from affecting the running system. 1622 1623 It is, however, intended as a diagnostic tool; if repeatable 1624 BIOS-originated corruption always affects the same memory, 1625 you can use memmap= to prevent the kernel from using that 1626 memory. 1627 1628config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1629 bool "Set the default setting of memory_corruption_check" 1630 depends on X86_CHECK_BIOS_CORRUPTION 1631 default y 1632 help 1633 Set whether the default state of memory_corruption_check is 1634 on or off. 1635 1636config MATH_EMULATION 1637 bool 1638 depends on MODIFY_LDT_SYSCALL 1639 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1640 help 1641 Linux can emulate a math coprocessor (used for floating point 1642 operations) if you don't have one. 486DX and Pentium processors have 1643 a math coprocessor built in, 486SX and 386 do not, unless you added 1644 a 487DX or 387, respectively. (The messages during boot time can 1645 give you some hints here ["man dmesg"].) Everyone needs either a 1646 coprocessor or this emulation. 1647 1648 If you don't have a math coprocessor, you need to say Y here; if you 1649 say Y here even though you have a coprocessor, the coprocessor will 1650 be used nevertheless. (This behavior can be changed with the kernel 1651 command line option "no387", which comes handy if your coprocessor 1652 is broken. Try "man bootparam" or see the documentation of your boot 1653 loader (lilo or loadlin) about how to pass options to the kernel at 1654 boot time.) This means that it is a good idea to say Y here if you 1655 intend to use this kernel on different machines. 1656 1657 More information about the internals of the Linux math coprocessor 1658 emulation can be found in <file:arch/x86/math-emu/README>. 1659 1660 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1661 kernel, it won't hurt. 1662 1663config MTRR 1664 def_bool y 1665 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1666 help 1667 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1668 the Memory Type Range Registers (MTRRs) may be used to control 1669 processor access to memory ranges. This is most useful if you have 1670 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1671 allows bus write transfers to be combined into a larger transfer 1672 before bursting over the PCI/AGP bus. This can increase performance 1673 of image write operations 2.5 times or more. Saying Y here creates a 1674 /proc/mtrr file which may be used to manipulate your processor's 1675 MTRRs. Typically the X server should use this. 1676 1677 This code has a reasonably generic interface so that similar 1678 control registers on other processors can be easily supported 1679 as well: 1680 1681 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1682 Registers (ARRs) which provide a similar functionality to MTRRs. For 1683 these, the ARRs are used to emulate the MTRRs. 1684 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1685 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1686 write-combining. All of these processors are supported by this code 1687 and it makes sense to say Y here if you have one of them. 1688 1689 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1690 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1691 can lead to all sorts of problems, so it's good to say Y here. 1692 1693 You can safely say Y even if your machine doesn't have MTRRs, you'll 1694 just add about 9 KB to your kernel. 1695 1696 See <file:Documentation/arch/x86/mtrr.rst> for more information. 1697 1698config MTRR_SANITIZER 1699 def_bool y 1700 prompt "MTRR cleanup support" 1701 depends on MTRR 1702 help 1703 Convert MTRR layout from continuous to discrete, so X drivers can 1704 add writeback entries. 1705 1706 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1707 The largest mtrr entry size for a continuous block can be set with 1708 mtrr_chunk_size. 1709 1710 If unsure, say Y. 1711 1712config MTRR_SANITIZER_ENABLE_DEFAULT 1713 int "MTRR cleanup enable value (0-1)" 1714 range 0 1 1715 default "0" 1716 depends on MTRR_SANITIZER 1717 help 1718 Enable mtrr cleanup default value 1719 1720config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1721 int "MTRR cleanup spare reg num (0-7)" 1722 range 0 7 1723 default "1" 1724 depends on MTRR_SANITIZER 1725 help 1726 mtrr cleanup spare entries default, it can be changed via 1727 mtrr_spare_reg_nr=N on the kernel command line. 1728 1729config X86_PAT 1730 def_bool y 1731 prompt "x86 PAT support" if EXPERT 1732 depends on MTRR 1733 select ARCH_USES_PG_ARCH_2 1734 help 1735 Use PAT attributes to setup page level cache control. 1736 1737 PATs are the modern equivalents of MTRRs and are much more 1738 flexible than MTRRs. 1739 1740 Say N here if you see bootup problems (boot crash, boot hang, 1741 spontaneous reboots) or a non-working video driver. 1742 1743 If unsure, say Y. 1744 1745config X86_UMIP 1746 def_bool y 1747 prompt "User Mode Instruction Prevention" if EXPERT 1748 help 1749 User Mode Instruction Prevention (UMIP) is a security feature in 1750 some x86 processors. If enabled, a general protection fault is 1751 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1752 executed in user mode. These instructions unnecessarily expose 1753 information about the hardware state. 1754 1755 The vast majority of applications do not use these instructions. 1756 For the very few that do, software emulation is provided in 1757 specific cases in protected and virtual-8086 modes. Emulated 1758 results are dummy. 1759 1760config CC_HAS_IBT 1761 # GCC >= 9 and binutils >= 2.29 1762 # Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654 1763 def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || CC_IS_CLANG) && \ 1764 $(as-instr,endbr64) 1765 1766config X86_CET 1767 def_bool n 1768 help 1769 CET features configured (Shadow stack or IBT) 1770 1771config X86_KERNEL_IBT 1772 prompt "Indirect Branch Tracking" 1773 def_bool y 1774 depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL 1775 select OBJTOOL 1776 select X86_CET 1777 help 1778 Build the kernel with support for Indirect Branch Tracking, a 1779 hardware support course-grain forward-edge Control Flow Integrity 1780 protection. It enforces that all indirect calls must land on 1781 an ENDBR instruction, as such, the compiler will instrument the 1782 code with them to make this happen. 1783 1784 In addition to building the kernel with IBT, seal all functions that 1785 are not indirect call targets, avoiding them ever becoming one. 1786 1787 This requires LTO like objtool runs and will slow down the build. It 1788 does significantly reduce the number of ENDBR instructions in the 1789 kernel image. 1790 1791config X86_INTEL_MEMORY_PROTECTION_KEYS 1792 prompt "Memory Protection Keys" 1793 def_bool y 1794 # Note: only available in 64-bit mode 1795 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1796 select ARCH_USES_HIGH_VMA_FLAGS 1797 select ARCH_HAS_PKEYS 1798 help 1799 Memory Protection Keys provides a mechanism for enforcing 1800 page-based protections, but without requiring modification of the 1801 page tables when an application changes protection domains. 1802 1803 For details, see Documentation/core-api/protection-keys.rst 1804 1805 If unsure, say y. 1806 1807config ARCH_PKEY_BITS 1808 int 1809 default 4 1810 1811choice 1812 prompt "TSX enable mode" 1813 depends on CPU_SUP_INTEL 1814 default X86_INTEL_TSX_MODE_AUTO 1815 help 1816 Intel's TSX (Transactional Synchronization Extensions) feature 1817 allows to optimize locking protocols through lock elision which 1818 can lead to a noticeable performance boost. 1819 1820 On the other hand it has been shown that TSX can be exploited 1821 to form side channel attacks (e.g. TAA) and chances are there 1822 will be more of those attacks discovered in the future. 1823 1824 Therefore TSX is not enabled by default (aka tsx=off). An admin 1825 might override this decision by tsx=on the command line parameter. 1826 Even with TSX enabled, the kernel will attempt to enable the best 1827 possible TAA mitigation setting depending on the microcode available 1828 for the particular machine. 1829 1830 This option allows to set the default tsx mode between tsx=on, =off 1831 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1832 details. 1833 1834 Say off if not sure, auto if TSX is in use but it should be used on safe 1835 platforms or on if TSX is in use and the security aspect of tsx is not 1836 relevant. 1837 1838config X86_INTEL_TSX_MODE_OFF 1839 bool "off" 1840 help 1841 TSX is disabled if possible - equals to tsx=off command line parameter. 1842 1843config X86_INTEL_TSX_MODE_ON 1844 bool "on" 1845 help 1846 TSX is always enabled on TSX capable HW - equals the tsx=on command 1847 line parameter. 1848 1849config X86_INTEL_TSX_MODE_AUTO 1850 bool "auto" 1851 help 1852 TSX is enabled on TSX capable HW that is believed to be safe against 1853 side channel attacks- equals the tsx=auto command line parameter. 1854endchoice 1855 1856config X86_SGX 1857 bool "Software Guard eXtensions (SGX)" 1858 depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC 1859 select CRYPTO_LIB_SHA256 1860 select MMU_NOTIFIER 1861 select NUMA_KEEP_MEMINFO if NUMA 1862 select XARRAY_MULTI 1863 help 1864 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1865 that can be used by applications to set aside private regions of code 1866 and data, referred to as enclaves. An enclave's private memory can 1867 only be accessed by code running within the enclave. Accesses from 1868 outside the enclave, including other enclaves, are disallowed by 1869 hardware. 1870 1871 If unsure, say N. 1872 1873config X86_USER_SHADOW_STACK 1874 bool "X86 userspace shadow stack" 1875 depends on AS_WRUSS 1876 depends on X86_64 1877 depends on PER_VMA_LOCK 1878 select ARCH_USES_HIGH_VMA_FLAGS 1879 select ARCH_HAS_USER_SHADOW_STACK 1880 select X86_CET 1881 help 1882 Shadow stack protection is a hardware feature that detects function 1883 return address corruption. This helps mitigate ROP attacks. 1884 Applications must be enabled to use it, and old userspace does not 1885 get protection "for free". 1886 1887 CPUs supporting shadow stacks were first released in 2020. 1888 1889 See Documentation/arch/x86/shstk.rst for more information. 1890 1891 If unsure, say N. 1892 1893config INTEL_TDX_HOST 1894 bool "Intel Trust Domain Extensions (TDX) host support" 1895 depends on CPU_SUP_INTEL 1896 depends on X86_64 1897 depends on KVM_INTEL 1898 depends on X86_X2APIC 1899 select ARCH_KEEP_MEMBLOCK 1900 depends on CONTIG_ALLOC 1901 depends on X86_MCE 1902 help 1903 Intel Trust Domain Extensions (TDX) protects guest VMs from malicious 1904 host and certain physical attacks. This option enables necessary TDX 1905 support in the host kernel to run confidential VMs. 1906 1907 If unsure, say N. 1908 1909config EFI 1910 bool "EFI runtime service support" 1911 depends on ACPI 1912 select UCS2_STRING 1913 select EFI_RUNTIME_WRAPPERS 1914 select ARCH_USE_MEMREMAP_PROT 1915 select EFI_RUNTIME_MAP if KEXEC_CORE 1916 help 1917 This enables the kernel to use EFI runtime services that are 1918 available (such as the EFI variable services). 1919 1920 This option is only useful on systems that have EFI firmware. 1921 In addition, you should use the latest ELILO loader available 1922 at <http://elilo.sourceforge.net> in order to take advantage 1923 of EFI runtime services. However, even with this option, the 1924 resultant kernel should continue to boot on existing non-EFI 1925 platforms. 1926 1927config EFI_STUB 1928 bool "EFI stub support" 1929 depends on EFI 1930 select RELOCATABLE 1931 help 1932 This kernel feature allows a bzImage to be loaded directly 1933 by EFI firmware without the use of a bootloader. 1934 1935 See Documentation/admin-guide/efi-stub.rst for more information. 1936 1937config EFI_HANDOVER_PROTOCOL 1938 bool "EFI handover protocol (DEPRECATED)" 1939 depends on EFI_STUB 1940 default y 1941 help 1942 Select this in order to include support for the deprecated EFI 1943 handover protocol, which defines alternative entry points into the 1944 EFI stub. This is a practice that has no basis in the UEFI 1945 specification, and requires a priori knowledge on the part of the 1946 bootloader about Linux/x86 specific ways of passing the command line 1947 and initrd, and where in memory those assets may be loaded. 1948 1949 If in doubt, say Y. Even though the corresponding support is not 1950 present in upstream GRUB or other bootloaders, most distros build 1951 GRUB with numerous downstream patches applied, and may rely on the 1952 handover protocol as as result. 1953 1954config EFI_MIXED 1955 bool "EFI mixed-mode support" 1956 depends on EFI_STUB && X86_64 1957 help 1958 Enabling this feature allows a 64-bit kernel to be booted 1959 on a 32-bit firmware, provided that your CPU supports 64-bit 1960 mode. 1961 1962 Note that it is not possible to boot a mixed-mode enabled 1963 kernel via the EFI boot stub - a bootloader that supports 1964 the EFI handover protocol must be used. 1965 1966 If unsure, say N. 1967 1968config EFI_RUNTIME_MAP 1969 bool "Export EFI runtime maps to sysfs" if EXPERT 1970 depends on EFI 1971 help 1972 Export EFI runtime memory regions to /sys/firmware/efi/runtime-map. 1973 That memory map is required by the 2nd kernel to set up EFI virtual 1974 mappings after kexec, but can also be used for debugging purposes. 1975 1976 See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map. 1977 1978source "kernel/Kconfig.hz" 1979 1980config ARCH_SUPPORTS_KEXEC 1981 def_bool y 1982 1983config ARCH_SUPPORTS_KEXEC_FILE 1984 def_bool X86_64 1985 1986config ARCH_SELECTS_KEXEC_FILE 1987 def_bool y 1988 depends on KEXEC_FILE 1989 select HAVE_IMA_KEXEC if IMA 1990 1991config ARCH_SUPPORTS_KEXEC_PURGATORY 1992 def_bool y 1993 1994config ARCH_SUPPORTS_KEXEC_SIG 1995 def_bool y 1996 1997config ARCH_SUPPORTS_KEXEC_SIG_FORCE 1998 def_bool y 1999 2000config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG 2001 def_bool y 2002 2003config ARCH_SUPPORTS_KEXEC_JUMP 2004 def_bool y 2005 2006config ARCH_SUPPORTS_KEXEC_HANDOVER 2007 def_bool X86_64 2008 2009config ARCH_SUPPORTS_CRASH_DUMP 2010 def_bool X86_64 || (X86_32 && HIGHMEM) 2011 2012config ARCH_DEFAULT_CRASH_DUMP 2013 def_bool y 2014 2015config ARCH_SUPPORTS_CRASH_HOTPLUG 2016 def_bool y 2017 2018config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION 2019 def_bool CRASH_RESERVE 2020 2021config PHYSICAL_START 2022 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2023 default "0x1000000" 2024 help 2025 This gives the physical address where the kernel is loaded. 2026 2027 If the kernel is not relocatable (CONFIG_RELOCATABLE=n) then bzImage 2028 will decompress itself to above physical address and run from there. 2029 Otherwise, bzImage will run from the address where it has been loaded 2030 by the boot loader. The only exception is if it is loaded below the 2031 above physical address, in which case it will relocate itself there. 2032 2033 In normal kdump cases one does not have to set/change this option 2034 as now bzImage can be compiled as a completely relocatable image 2035 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2036 address. This option is mainly useful for the folks who don't want 2037 to use a bzImage for capturing the crash dump and want to use a 2038 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2039 to be specifically compiled to run from a specific memory area 2040 (normally a reserved region) and this option comes handy. 2041 2042 So if you are using bzImage for capturing the crash dump, 2043 leave the value here unchanged to 0x1000000 and set 2044 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2045 for capturing the crash dump change this value to start of 2046 the reserved region. In other words, it can be set based on 2047 the "X" value as specified in the "crashkernel=YM@XM" 2048 command line boot parameter passed to the panic-ed 2049 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2050 for more details about crash dumps. 2051 2052 Usage of bzImage for capturing the crash dump is recommended as 2053 one does not have to build two kernels. Same kernel can be used 2054 as production kernel and capture kernel. Above option should have 2055 gone away after relocatable bzImage support is introduced. But it 2056 is present because there are users out there who continue to use 2057 vmlinux for dump capture. This option should go away down the 2058 line. 2059 2060 Don't change this unless you know what you are doing. 2061 2062config RELOCATABLE 2063 bool "Build a relocatable kernel" 2064 default y 2065 help 2066 This builds a kernel image that retains relocation information 2067 so it can be loaded someplace besides the default 1MB. 2068 The relocations tend to make the kernel binary about 10% larger, 2069 but are discarded at runtime. 2070 2071 One use is for the kexec on panic case where the recovery kernel 2072 must live at a different physical address than the primary 2073 kernel. 2074 2075 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2076 it has been loaded at and the compile time physical address 2077 (CONFIG_PHYSICAL_START) is used as the minimum location. 2078 2079config RANDOMIZE_BASE 2080 bool "Randomize the address of the kernel image (KASLR)" 2081 depends on RELOCATABLE 2082 default y 2083 help 2084 In support of Kernel Address Space Layout Randomization (KASLR), 2085 this randomizes the physical address at which the kernel image 2086 is decompressed and the virtual address where the kernel 2087 image is mapped, as a security feature that deters exploit 2088 attempts relying on knowledge of the location of kernel 2089 code internals. 2090 2091 On 64-bit, the kernel physical and virtual addresses are 2092 randomized separately. The physical address will be anywhere 2093 between 16MB and the top of physical memory (up to 64TB). The 2094 virtual address will be randomized from 16MB up to 1GB (9 bits 2095 of entropy). Note that this also reduces the memory space 2096 available to kernel modules from 1.5GB to 1GB. 2097 2098 On 32-bit, the kernel physical and virtual addresses are 2099 randomized together. They will be randomized from 16MB up to 2100 512MB (8 bits of entropy). 2101 2102 Entropy is generated using the RDRAND instruction if it is 2103 supported. If RDTSC is supported, its value is mixed into 2104 the entropy pool as well. If neither RDRAND nor RDTSC are 2105 supported, then entropy is read from the i8254 timer. The 2106 usable entropy is limited by the kernel being built using 2107 2GB addressing, and that PHYSICAL_ALIGN must be at a 2108 minimum of 2MB. As a result, only 10 bits of entropy are 2109 theoretically possible, but the implementations are further 2110 limited due to memory layouts. 2111 2112 If unsure, say Y. 2113 2114# Relocation on x86 needs some additional build support 2115config X86_NEED_RELOCS 2116 def_bool y 2117 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2118 select ARCH_VMLINUX_NEEDS_RELOCS 2119 2120config PHYSICAL_ALIGN 2121 hex "Alignment value to which kernel should be aligned" 2122 default "0x200000" 2123 range 0x2000 0x1000000 if X86_32 2124 range 0x200000 0x1000000 if X86_64 2125 help 2126 This value puts the alignment restrictions on physical address 2127 where kernel is loaded and run from. Kernel is compiled for an 2128 address which meets above alignment restriction. 2129 2130 If bootloader loads the kernel at a non-aligned address and 2131 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2132 address aligned to above value and run from there. 2133 2134 If bootloader loads the kernel at a non-aligned address and 2135 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2136 load address and decompress itself to the address it has been 2137 compiled for and run from there. The address for which kernel is 2138 compiled already meets above alignment restrictions. Hence the 2139 end result is that kernel runs from a physical address meeting 2140 above alignment restrictions. 2141 2142 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2143 this value must be a multiple of 0x200000. 2144 2145 Don't change this unless you know what you are doing. 2146 2147config RANDOMIZE_MEMORY 2148 bool "Randomize the kernel memory sections" 2149 depends on X86_64 2150 depends on RANDOMIZE_BASE 2151 default RANDOMIZE_BASE 2152 help 2153 Randomizes the base virtual address of kernel memory sections 2154 (physical memory mapping, vmalloc & vmemmap). This security feature 2155 makes exploits relying on predictable memory locations less reliable. 2156 2157 The order of allocations remains unchanged. Entropy is generated in 2158 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2159 configuration have in average 30,000 different possible virtual 2160 addresses for each memory section. 2161 2162 If unsure, say Y. 2163 2164config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2165 hex "Physical memory mapping padding" if EXPERT 2166 depends on RANDOMIZE_MEMORY 2167 default "0xa" if MEMORY_HOTPLUG 2168 default "0x0" 2169 range 0x1 0x40 if MEMORY_HOTPLUG 2170 range 0x0 0x40 2171 help 2172 Define the padding in terabytes added to the existing physical 2173 memory size during kernel memory randomization. It is useful 2174 for memory hotplug support but reduces the entropy available for 2175 address randomization. 2176 2177 If unsure, leave at the default value. 2178 2179config ADDRESS_MASKING 2180 bool "Linear Address Masking support" 2181 depends on X86_64 2182 depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS 2183 help 2184 Linear Address Masking (LAM) modifies the checking that is applied 2185 to 64-bit linear addresses, allowing software to use of the 2186 untranslated address bits for metadata. 2187 2188 The capability can be used for efficient address sanitizers (ASAN) 2189 implementation and for optimizations in JITs. 2190 2191config HOTPLUG_CPU 2192 def_bool y 2193 depends on SMP 2194 2195config COMPAT_VDSO 2196 def_bool n 2197 prompt "Workaround for glibc 2.3.2 / 2.3.3 (released in year 2003/2004)" 2198 depends on COMPAT_32 2199 help 2200 Certain buggy versions of glibc will crash if they are 2201 presented with a 32-bit vDSO that is not mapped at the address 2202 indicated in its segment table. 2203 2204 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2205 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2206 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2207 the only released version with the bug, but OpenSUSE 9 2208 contains a buggy "glibc 2.3.2". 2209 2210 The symptom of the bug is that everything crashes on startup, saying: 2211 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2212 2213 Saying Y here changes the default value of the vdso32 boot 2214 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2215 This works around the glibc bug but hurts performance. 2216 2217 If unsure, say N: if you are compiling your own kernel, you 2218 are unlikely to be using a buggy version of glibc. 2219 2220choice 2221 prompt "vsyscall table for legacy applications" 2222 depends on X86_64 2223 default LEGACY_VSYSCALL_XONLY 2224 help 2225 Legacy user code that does not know how to find the vDSO expects 2226 to be able to issue three syscalls by calling fixed addresses in 2227 kernel space. Since this location is not randomized with ASLR, 2228 it can be used to assist security vulnerability exploitation. 2229 2230 This setting can be changed at boot time via the kernel command 2231 line parameter vsyscall=[emulate|xonly|none]. Emulate mode 2232 is deprecated and can only be enabled using the kernel command 2233 line. 2234 2235 On a system with recent enough glibc (2.14 or newer) and no 2236 static binaries, you can say None without a performance penalty 2237 to improve security. 2238 2239 If unsure, select "Emulate execution only". 2240 2241 config LEGACY_VSYSCALL_XONLY 2242 bool "Emulate execution only" 2243 help 2244 The kernel traps and emulates calls into the fixed vsyscall 2245 address mapping and does not allow reads. This 2246 configuration is recommended when userspace might use the 2247 legacy vsyscall area but support for legacy binary 2248 instrumentation of legacy code is not needed. It mitigates 2249 certain uses of the vsyscall area as an ASLR-bypassing 2250 buffer. 2251 2252 config LEGACY_VSYSCALL_NONE 2253 bool "None" 2254 help 2255 There will be no vsyscall mapping at all. This will 2256 eliminate any risk of ASLR bypass due to the vsyscall 2257 fixed address mapping. Attempts to use the vsyscalls 2258 will be reported to dmesg, so that either old or 2259 malicious userspace programs can be identified. 2260 2261endchoice 2262 2263config CMDLINE_BOOL 2264 bool "Built-in kernel command line" 2265 help 2266 Allow for specifying boot arguments to the kernel at 2267 build time. On some systems (e.g. embedded ones), it is 2268 necessary or convenient to provide some or all of the 2269 kernel boot arguments with the kernel itself (that is, 2270 to not rely on the boot loader to provide them.) 2271 2272 To compile command line arguments into the kernel, 2273 set this option to 'Y', then fill in the 2274 boot arguments in CONFIG_CMDLINE. 2275 2276 Systems with fully functional boot loaders (i.e. non-embedded) 2277 should leave this option set to 'N'. 2278 2279config CMDLINE 2280 string "Built-in kernel command string" 2281 depends on CMDLINE_BOOL 2282 default "" 2283 help 2284 Enter arguments here that should be compiled into the kernel 2285 image and used at boot time. If the boot loader provides a 2286 command line at boot time, it is appended to this string to 2287 form the full kernel command line, when the system boots. 2288 2289 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2290 change this behavior. 2291 2292 In most cases, the command line (whether built-in or provided 2293 by the boot loader) should specify the device for the root 2294 file system. 2295 2296config CMDLINE_OVERRIDE 2297 bool "Built-in command line overrides boot loader arguments" 2298 depends on CMDLINE_BOOL && CMDLINE != "" 2299 help 2300 Set this option to 'Y' to have the kernel ignore the boot loader 2301 command line, and use ONLY the built-in command line. 2302 2303 This is used to work around broken boot loaders. This should 2304 be set to 'N' under normal conditions. 2305 2306config MODIFY_LDT_SYSCALL 2307 bool "Enable the LDT (local descriptor table)" if EXPERT 2308 default y 2309 help 2310 Linux can allow user programs to install a per-process x86 2311 Local Descriptor Table (LDT) using the modify_ldt(2) system 2312 call. This is required to run 16-bit or segmented code such as 2313 DOSEMU or some Wine programs. It is also used by some very old 2314 threading libraries. 2315 2316 Enabling this feature adds a small amount of overhead to 2317 context switches and increases the low-level kernel attack 2318 surface. Disabling it removes the modify_ldt(2) system call. 2319 2320 Saying 'N' here may make sense for embedded or server kernels. 2321 2322config STRICT_SIGALTSTACK_SIZE 2323 bool "Enforce strict size checking for sigaltstack" 2324 depends on DYNAMIC_SIGFRAME 2325 help 2326 For historical reasons MINSIGSTKSZ is a constant which became 2327 already too small with AVX512 support. Add a mechanism to 2328 enforce strict checking of the sigaltstack size against the 2329 real size of the FPU frame. This option enables the check 2330 by default. It can also be controlled via the kernel command 2331 line option 'strict_sas_size' independent of this config 2332 switch. Enabling it might break existing applications which 2333 allocate a too small sigaltstack but 'work' because they 2334 never get a signal delivered. 2335 2336 Say 'N' unless you want to really enforce this check. 2337 2338config CFI_AUTO_DEFAULT 2339 bool "Attempt to use FineIBT by default at boot time" 2340 depends on FINEIBT 2341 depends on !RUST || RUSTC_VERSION >= 108800 2342 default y 2343 help 2344 Attempt to use FineIBT by default at boot time. If enabled, 2345 this is the same as booting with "cfi=auto". If disabled, 2346 this is the same as booting with "cfi=kcfi". 2347 2348source "kernel/livepatch/Kconfig" 2349 2350config X86_BUS_LOCK_DETECT 2351 bool "Split Lock Detect and Bus Lock Detect support" 2352 depends on CPU_SUP_INTEL || CPU_SUP_AMD 2353 default y 2354 help 2355 Enable Split Lock Detect and Bus Lock Detect functionalities. 2356 See <file:Documentation/arch/x86/buslock.rst> for more information. 2357 2358endmenu 2359 2360config CC_HAS_NAMED_AS 2361 def_bool $(success,echo 'int __seg_fs fs; int __seg_gs gs;' | $(CC) -x c - -S -o /dev/null) 2362 depends on CC_IS_GCC 2363 2364# 2365# -fsanitize=kernel-address (KASAN) and -fsanitize=thread (KCSAN) 2366# are incompatible with named address spaces with GCC < 13.3 2367# (see GCC PR sanitizer/111736 and also PR sanitizer/115172). 2368# 2369 2370config CC_HAS_NAMED_AS_FIXED_SANITIZERS 2371 def_bool y 2372 depends on !(KASAN || KCSAN) || GCC_VERSION >= 130300 2373 depends on !(UBSAN_BOOL && KASAN) || GCC_VERSION >= 140200 2374 2375config USE_X86_SEG_SUPPORT 2376 def_bool CC_HAS_NAMED_AS 2377 depends on CC_HAS_NAMED_AS_FIXED_SANITIZERS 2378 2379config CC_HAS_SLS 2380 def_bool $(cc-option,-mharden-sls=all) 2381 2382config CC_HAS_RETURN_THUNK 2383 def_bool $(cc-option,-mfunction-return=thunk-extern) 2384 2385config CC_HAS_ENTRY_PADDING 2386 def_bool $(cc-option,-fpatchable-function-entry=16,16) 2387 2388config CC_HAS_KCFI_ARITY 2389 def_bool $(cc-option,-fsanitize=kcfi -fsanitize-kcfi-arity) 2390 depends on CC_IS_CLANG && !RUST 2391 2392config FUNCTION_PADDING_CFI 2393 int 2394 default 59 if FUNCTION_ALIGNMENT_64B 2395 default 27 if FUNCTION_ALIGNMENT_32B 2396 default 11 if FUNCTION_ALIGNMENT_16B 2397 default 3 if FUNCTION_ALIGNMENT_8B 2398 default 0 2399 2400# Basically: FUNCTION_ALIGNMENT - 5*CFI 2401# except Kconfig can't do arithmetic :/ 2402config FUNCTION_PADDING_BYTES 2403 int 2404 default FUNCTION_PADDING_CFI if CFI 2405 default FUNCTION_ALIGNMENT 2406 2407config CALL_PADDING 2408 def_bool n 2409 depends on CC_HAS_ENTRY_PADDING && OBJTOOL 2410 select FUNCTION_ALIGNMENT_16B 2411 2412config FINEIBT 2413 def_bool y 2414 depends on X86_KERNEL_IBT && CFI && MITIGATION_RETPOLINE 2415 select CALL_PADDING 2416 2417config FINEIBT_BHI 2418 def_bool y 2419 depends on FINEIBT && CC_HAS_KCFI_ARITY 2420 2421config HAVE_CALL_THUNKS 2422 def_bool y 2423 depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL 2424 2425config CALL_THUNKS 2426 def_bool n 2427 select CALL_PADDING 2428 2429config PREFIX_SYMBOLS 2430 def_bool y 2431 depends on CALL_PADDING && !CFI 2432 2433menuconfig CPU_MITIGATIONS 2434 bool "Mitigations for CPU vulnerabilities" 2435 default y 2436 help 2437 Say Y here to enable options which enable mitigations for hardware 2438 vulnerabilities (usually related to speculative execution). 2439 Mitigations can be disabled or restricted to SMT systems at runtime 2440 via the "mitigations" kernel parameter. 2441 2442 If you say N, all mitigations will be disabled. This CANNOT be 2443 overridden at runtime. 2444 2445 Say 'Y', unless you really know what you are doing. 2446 2447if CPU_MITIGATIONS 2448 2449config MITIGATION_PAGE_TABLE_ISOLATION 2450 bool "Remove the kernel mapping in user mode" 2451 default y 2452 depends on (X86_64 || X86_PAE) 2453 help 2454 This feature reduces the number of hardware side channels by 2455 ensuring that the majority of kernel addresses are not mapped 2456 into userspace. 2457 2458 See Documentation/arch/x86/pti.rst for more details. 2459 2460config MITIGATION_RETPOLINE 2461 bool "Avoid speculative indirect branches in kernel" 2462 select OBJTOOL if HAVE_OBJTOOL 2463 default y 2464 help 2465 Compile kernel with the retpoline compiler options to guard against 2466 kernel-to-user data leaks by avoiding speculative indirect 2467 branches. Requires a compiler with -mindirect-branch=thunk-extern 2468 support for full protection. The kernel may run slower. 2469 2470config MITIGATION_RETHUNK 2471 bool "Enable return-thunks" 2472 depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK 2473 select OBJTOOL if HAVE_OBJTOOL 2474 default y if X86_64 2475 help 2476 Compile the kernel with the return-thunks compiler option to guard 2477 against kernel-to-user data leaks by avoiding return speculation. 2478 Requires a compiler with -mfunction-return=thunk-extern 2479 support for full protection. The kernel may run slower. 2480 2481config MITIGATION_UNRET_ENTRY 2482 bool "Enable UNRET on kernel entry" 2483 depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64 2484 default y 2485 help 2486 Compile the kernel with support for the retbleed=unret mitigation. 2487 2488config MITIGATION_CALL_DEPTH_TRACKING 2489 bool "Mitigate RSB underflow with call depth tracking" 2490 depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS 2491 select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 2492 select CALL_THUNKS 2493 default y 2494 help 2495 Compile the kernel with call depth tracking to mitigate the Intel 2496 SKL Return-Stack-Buffer (RSB) underflow issue. The mitigation is off 2497 by default and needs to be enabled on the kernel command line via the 2498 retbleed=stuff option. For non-affected systems the overhead of this 2499 option is marginal as the call depth tracking is using run-time 2500 generated call thunks in a compiler generated padding area and call 2501 patching. This increases text size by ~5%. For non affected systems 2502 this space is unused. On affected SKL systems this results in a 2503 significant performance gain over the IBRS mitigation. 2504 2505config CALL_THUNKS_DEBUG 2506 bool "Enable call thunks and call depth tracking debugging" 2507 depends on MITIGATION_CALL_DEPTH_TRACKING 2508 select FUNCTION_ALIGNMENT_32B 2509 default n 2510 help 2511 Enable call/ret counters for imbalance detection and build in 2512 a noisy dmesg about callthunks generation and call patching for 2513 trouble shooting. The debug prints need to be enabled on the 2514 kernel command line with 'debug-callthunks'. 2515 Only enable this when you are debugging call thunks as this 2516 creates a noticeable runtime overhead. If unsure say N. 2517 2518config MITIGATION_IBPB_ENTRY 2519 bool "Enable IBPB on kernel entry" 2520 depends on CPU_SUP_AMD && X86_64 2521 default y 2522 help 2523 Compile the kernel with support for the retbleed=ibpb and 2524 spec_rstack_overflow={ibpb,ibpb-vmexit} mitigations. 2525 2526config MITIGATION_IBRS_ENTRY 2527 bool "Enable IBRS on kernel entry" 2528 depends on CPU_SUP_INTEL && X86_64 2529 default y 2530 help 2531 Compile the kernel with support for the spectre_v2=ibrs mitigation. 2532 This mitigates both spectre_v2 and retbleed at great cost to 2533 performance. 2534 2535config MITIGATION_SRSO 2536 bool "Mitigate speculative RAS overflow on AMD" 2537 depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK 2538 default y 2539 help 2540 Enable the SRSO mitigation needed on AMD Zen1-4 machines. 2541 2542config MITIGATION_SLS 2543 bool "Mitigate Straight-Line-Speculation" 2544 depends on CC_HAS_SLS && X86_64 2545 select OBJTOOL if HAVE_OBJTOOL 2546 default n 2547 help 2548 Compile the kernel with straight-line-speculation options to guard 2549 against straight line speculation. The kernel image might be slightly 2550 larger. 2551 2552config MITIGATION_GDS 2553 bool "Mitigate Gather Data Sampling" 2554 depends on CPU_SUP_INTEL 2555 default y 2556 help 2557 Enable mitigation for Gather Data Sampling (GDS). GDS is a hardware 2558 vulnerability which allows unprivileged speculative access to data 2559 which was previously stored in vector registers. The attacker uses gather 2560 instructions to infer the stale vector register data. 2561 2562config MITIGATION_RFDS 2563 bool "RFDS Mitigation" 2564 depends on CPU_SUP_INTEL 2565 default y 2566 help 2567 Enable mitigation for Register File Data Sampling (RFDS) by default. 2568 RFDS is a hardware vulnerability which affects Intel Atom CPUs. It 2569 allows unprivileged speculative access to stale data previously 2570 stored in floating point, vector and integer registers. 2571 See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst> 2572 2573config MITIGATION_SPECTRE_BHI 2574 bool "Mitigate Spectre-BHB (Branch History Injection)" 2575 depends on CPU_SUP_INTEL 2576 default y 2577 help 2578 Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks 2579 where the branch history buffer is poisoned to speculatively steer 2580 indirect branches. 2581 See <file:Documentation/admin-guide/hw-vuln/spectre.rst> 2582 2583config MITIGATION_MDS 2584 bool "Mitigate Microarchitectural Data Sampling (MDS) hardware bug" 2585 depends on CPU_SUP_INTEL 2586 default y 2587 help 2588 Enable mitigation for Microarchitectural Data Sampling (MDS). MDS is 2589 a hardware vulnerability which allows unprivileged speculative access 2590 to data which is available in various CPU internal buffers. 2591 See also <file:Documentation/admin-guide/hw-vuln/mds.rst> 2592 2593config MITIGATION_TAA 2594 bool "Mitigate TSX Asynchronous Abort (TAA) hardware bug" 2595 depends on CPU_SUP_INTEL 2596 default y 2597 help 2598 Enable mitigation for TSX Asynchronous Abort (TAA). TAA is a hardware 2599 vulnerability that allows unprivileged speculative access to data 2600 which is available in various CPU internal buffers by using 2601 asynchronous aborts within an Intel TSX transactional region. 2602 See also <file:Documentation/admin-guide/hw-vuln/tsx_async_abort.rst> 2603 2604config MITIGATION_MMIO_STALE_DATA 2605 bool "Mitigate MMIO Stale Data hardware bug" 2606 depends on CPU_SUP_INTEL 2607 default y 2608 help 2609 Enable mitigation for MMIO Stale Data hardware bugs. Processor MMIO 2610 Stale Data Vulnerabilities are a class of memory-mapped I/O (MMIO) 2611 vulnerabilities that can expose data. The vulnerabilities require the 2612 attacker to have access to MMIO. 2613 See also 2614 <file:Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst> 2615 2616config MITIGATION_L1TF 2617 bool "Mitigate L1 Terminal Fault (L1TF) hardware bug" 2618 depends on CPU_SUP_INTEL 2619 default y 2620 help 2621 Mitigate L1 Terminal Fault (L1TF) hardware bug. L1 Terminal Fault is a 2622 hardware vulnerability which allows unprivileged speculative access to data 2623 available in the Level 1 Data Cache. 2624 See <file:Documentation/admin-guide/hw-vuln/l1tf.rst 2625 2626config MITIGATION_RETBLEED 2627 bool "Mitigate RETBleed hardware bug" 2628 depends on (CPU_SUP_INTEL && MITIGATION_SPECTRE_V2) || MITIGATION_UNRET_ENTRY || MITIGATION_IBPB_ENTRY 2629 default y 2630 help 2631 Enable mitigation for RETBleed (Arbitrary Speculative Code Execution 2632 with Return Instructions) vulnerability. RETBleed is a speculative 2633 execution attack which takes advantage of microarchitectural behavior 2634 in many modern microprocessors, similar to Spectre v2. An 2635 unprivileged attacker can use these flaws to bypass conventional 2636 memory security restrictions to gain read access to privileged memory 2637 that would otherwise be inaccessible. 2638 2639config MITIGATION_SPECTRE_V1 2640 bool "Mitigate SPECTRE V1 hardware bug" 2641 default y 2642 help 2643 Enable mitigation for Spectre V1 (Bounds Check Bypass). Spectre V1 is a 2644 class of side channel attacks that takes advantage of speculative 2645 execution that bypasses conditional branch instructions used for 2646 memory access bounds check. 2647 See also <file:Documentation/admin-guide/hw-vuln/spectre.rst> 2648 2649config MITIGATION_SPECTRE_V2 2650 bool "Mitigate SPECTRE V2 hardware bug" 2651 default y 2652 help 2653 Enable mitigation for Spectre V2 (Branch Target Injection). Spectre 2654 V2 is a class of side channel attacks that takes advantage of 2655 indirect branch predictors inside the processor. In Spectre variant 2 2656 attacks, the attacker can steer speculative indirect branches in the 2657 victim to gadget code by poisoning the branch target buffer of a CPU 2658 used for predicting indirect branch addresses. 2659 See also <file:Documentation/admin-guide/hw-vuln/spectre.rst> 2660 2661config MITIGATION_SRBDS 2662 bool "Mitigate Special Register Buffer Data Sampling (SRBDS) hardware bug" 2663 depends on CPU_SUP_INTEL 2664 default y 2665 help 2666 Enable mitigation for Special Register Buffer Data Sampling (SRBDS). 2667 SRBDS is a hardware vulnerability that allows Microarchitectural Data 2668 Sampling (MDS) techniques to infer values returned from special 2669 register accesses. An unprivileged user can extract values returned 2670 from RDRAND and RDSEED executed on another core or sibling thread 2671 using MDS techniques. 2672 See also 2673 <file:Documentation/admin-guide/hw-vuln/special-register-buffer-data-sampling.rst> 2674 2675config MITIGATION_SSB 2676 bool "Mitigate Speculative Store Bypass (SSB) hardware bug" 2677 default y 2678 help 2679 Enable mitigation for Speculative Store Bypass (SSB). SSB is a 2680 hardware security vulnerability and its exploitation takes advantage 2681 of speculative execution in a similar way to the Meltdown and Spectre 2682 security vulnerabilities. 2683 2684config MITIGATION_ITS 2685 bool "Enable Indirect Target Selection mitigation" 2686 depends on CPU_SUP_INTEL && X86_64 2687 depends on MITIGATION_RETPOLINE && MITIGATION_RETHUNK 2688 select EXECMEM 2689 default y 2690 help 2691 Enable Indirect Target Selection (ITS) mitigation. ITS is a bug in 2692 BPU on some Intel CPUs that may allow Spectre V2 style attacks. If 2693 disabled, mitigation cannot be enabled via cmdline. 2694 See <file:Documentation/admin-guide/hw-vuln/indirect-target-selection.rst> 2695 2696config MITIGATION_TSA 2697 bool "Mitigate Transient Scheduler Attacks" 2698 depends on CPU_SUP_AMD 2699 default y 2700 help 2701 Enable mitigation for Transient Scheduler Attacks. TSA is a hardware 2702 security vulnerability on AMD CPUs which can lead to forwarding of 2703 invalid info to subsequent instructions and thus can affect their 2704 timing and thereby cause a leakage. 2705 2706config MITIGATION_VMSCAPE 2707 bool "Mitigate VMSCAPE" 2708 depends on KVM 2709 default y 2710 help 2711 Enable mitigation for VMSCAPE attacks. VMSCAPE is a hardware security 2712 vulnerability on Intel and AMD CPUs that may allow a guest to do 2713 Spectre v2 style attacks on userspace hypervisor. 2714endif 2715 2716config ARCH_HAS_ADD_PAGES 2717 def_bool y 2718 depends on ARCH_ENABLE_MEMORY_HOTPLUG 2719 2720menu "Power management and ACPI options" 2721 2722config ARCH_HIBERNATION_HEADER 2723 def_bool y 2724 depends on HIBERNATION 2725 2726source "kernel/power/Kconfig" 2727 2728source "drivers/acpi/Kconfig" 2729 2730config X86_APM_BOOT 2731 def_bool y 2732 depends on APM 2733 2734menuconfig APM 2735 tristate "APM (Advanced Power Management) BIOS support" 2736 depends on X86_32 && PM_SLEEP 2737 help 2738 APM is a BIOS specification for saving power using several different 2739 techniques. This is mostly useful for battery powered laptops with 2740 APM compliant BIOSes. If you say Y here, the system time will be 2741 reset after a RESUME operation, the /proc/apm device will provide 2742 battery status information, and user-space programs will receive 2743 notification of APM "events" (e.g. battery status change). 2744 2745 If you select "Y" here, you can disable actual use of the APM 2746 BIOS by passing the "apm=off" option to the kernel at boot time. 2747 2748 Note that the APM support is almost completely disabled for 2749 machines with more than one CPU. 2750 2751 In order to use APM, you will need supporting software. For location 2752 and more information, read <file:Documentation/power/apm-acpi.rst> 2753 and the Battery Powered Linux mini-HOWTO, available from 2754 <http://www.tldp.org/docs.html#howto>. 2755 2756 This driver does not spin down disk drives (see the hdparm(8) 2757 manpage ("man 8 hdparm") for that), and it doesn't turn off 2758 VESA-compliant "green" monitors. 2759 2760 Generally, if you don't have a battery in your machine, there isn't 2761 much point in using this driver and you should say N. If you get 2762 random kernel OOPSes or reboots that don't seem to be related to 2763 anything, try disabling/enabling this option (or disabling/enabling 2764 APM in your BIOS). 2765 2766 Some other things you should try when experiencing seemingly random, 2767 "weird" problems: 2768 2769 1) make sure that you have enough swap space and that it is 2770 enabled. 2771 2) pass the "idle=poll" option to the kernel 2772 3) switch on floating point emulation in the kernel and pass 2773 the "no387" option to the kernel 2774 4) pass the "floppy=nodma" option to the kernel 2775 5) pass the "mem=4M" option to the kernel (thereby disabling 2776 all but the first 4 MB of RAM) 2777 6) make sure that the CPU is not over clocked. 2778 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2779 8) disable the cache from your BIOS settings 2780 9) install a fan for the video card or exchange video RAM 2781 10) install a better fan for the CPU 2782 11) exchange RAM chips 2783 12) exchange the motherboard. 2784 2785 To compile this driver as a module, choose M here: the 2786 module will be called apm. 2787 2788if APM 2789 2790config APM_IGNORE_USER_SUSPEND 2791 bool "Ignore USER SUSPEND" 2792 help 2793 This option will ignore USER SUSPEND requests. On machines with a 2794 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2795 series notebooks, it is necessary to say Y because of a BIOS bug. 2796 2797config APM_DO_ENABLE 2798 bool "Enable PM at boot time" 2799 help 2800 Enable APM features at boot time. From page 36 of the APM BIOS 2801 specification: "When disabled, the APM BIOS does not automatically 2802 power manage devices, enter the Standby State, enter the Suspend 2803 State, or take power saving steps in response to CPU Idle calls." 2804 This driver will make CPU Idle calls when Linux is idle (unless this 2805 feature is turned off -- see "Do CPU IDLE calls", below). This 2806 should always save battery power, but more complicated APM features 2807 will be dependent on your BIOS implementation. You may need to turn 2808 this option off if your computer hangs at boot time when using APM 2809 support, or if it beeps continuously instead of suspending. Turn 2810 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2811 T400CDT. This is off by default since most machines do fine without 2812 this feature. 2813 2814config APM_CPU_IDLE 2815 depends on CPU_IDLE 2816 bool "Make CPU Idle calls when idle" 2817 help 2818 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2819 On some machines, this can activate improved power savings, such as 2820 a slowed CPU clock rate, when the machine is idle. These idle calls 2821 are made after the idle loop has run for some length of time (e.g., 2822 333 mS). On some machines, this will cause a hang at boot time or 2823 whenever the CPU becomes idle. (On machines with more than one CPU, 2824 this option does nothing.) 2825 2826config APM_DISPLAY_BLANK 2827 bool "Enable console blanking using APM" 2828 help 2829 Enable console blanking using the APM. Some laptops can use this to 2830 turn off the LCD backlight when the screen blanker of the Linux 2831 virtual console blanks the screen. Note that this is only used by 2832 the virtual console screen blanker, and won't turn off the backlight 2833 when using the X Window system. This also doesn't have anything to 2834 do with your VESA-compliant power-saving monitor. Further, this 2835 option doesn't work for all laptops -- it might not turn off your 2836 backlight at all, or it might print a lot of errors to the console, 2837 especially if you are using gpm. 2838 2839config APM_ALLOW_INTS 2840 bool "Allow interrupts during APM BIOS calls" 2841 help 2842 Normally we disable external interrupts while we are making calls to 2843 the APM BIOS as a measure to lessen the effects of a badly behaving 2844 BIOS implementation. The BIOS should reenable interrupts if it 2845 needs to. Unfortunately, some BIOSes do not -- especially those in 2846 many of the newer IBM Thinkpads. If you experience hangs when you 2847 suspend, try setting this to Y. Otherwise, say N. 2848 2849endif # APM 2850 2851source "drivers/cpufreq/Kconfig" 2852 2853source "drivers/cpuidle/Kconfig" 2854 2855source "drivers/idle/Kconfig" 2856 2857endmenu 2858 2859menu "Bus options (PCI etc.)" 2860 2861choice 2862 prompt "PCI access mode" 2863 depends on X86_32 && PCI 2864 default PCI_GOANY 2865 help 2866 On PCI systems, the BIOS can be used to detect the PCI devices and 2867 determine their configuration. However, some old PCI motherboards 2868 have BIOS bugs and may crash if this is done. Also, some embedded 2869 PCI-based systems don't have any BIOS at all. Linux can also try to 2870 detect the PCI hardware directly without using the BIOS. 2871 2872 With this option, you can specify how Linux should detect the 2873 PCI devices. If you choose "BIOS", the BIOS will be used, 2874 if you choose "Direct", the BIOS won't be used, and if you 2875 choose "MMConfig", then PCI Express MMCONFIG will be used. 2876 If you choose "Any", the kernel will try MMCONFIG, then the 2877 direct access method and falls back to the BIOS if that doesn't 2878 work. If unsure, go with the default, which is "Any". 2879 2880config PCI_GOBIOS 2881 bool "BIOS" 2882 2883config PCI_GOMMCONFIG 2884 bool "MMConfig" 2885 2886config PCI_GODIRECT 2887 bool "Direct" 2888 2889config PCI_GOOLPC 2890 bool "OLPC XO-1" 2891 depends on OLPC 2892 2893config PCI_GOANY 2894 bool "Any" 2895 2896endchoice 2897 2898config PCI_BIOS 2899 def_bool y 2900 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2901 2902# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2903config PCI_DIRECT 2904 def_bool y 2905 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2906 2907config PCI_MMCONFIG 2908 bool "Support mmconfig PCI config space access" if X86_64 2909 default y 2910 depends on PCI && (ACPI || JAILHOUSE_GUEST) 2911 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2912 help 2913 Add support for accessing the PCI configuration space as a memory 2914 mapped area. It is the recommended method if the system supports 2915 this (it must have PCI Express and ACPI for it to be available). 2916 2917 In the unlikely case that enabling this configuration option causes 2918 problems, the mechanism can be switched off with the 'pci=nommconf' 2919 command line parameter. 2920 2921 Say N only if you are sure that your platform does not support this 2922 access method or you have problems caused by it. 2923 2924 Say Y otherwise. 2925 2926config PCI_OLPC 2927 def_bool y 2928 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2929 2930config PCI_XEN 2931 def_bool y 2932 depends on PCI && XEN 2933 2934config MMCONF_FAM10H 2935 def_bool y 2936 depends on X86_64 && PCI_MMCONFIG && ACPI 2937 2938config PCI_CNB20LE_QUIRK 2939 bool "Read PCI host bridge windows from the CNB20LE chipset" if EXPERT 2940 depends on X86_32 && PCI 2941 help 2942 Read the PCI windows out of the CNB20LE host bridge. This allows 2943 PCI hotplug to work on systems with the CNB20LE chipset which do 2944 not have ACPI. 2945 2946 The ServerWorks (later Broadcom) CNB20LE was a chipset designed 2947 most probably only for Pentium III. 2948 2949 To find out if you have such a chipset, search for a PCI device with 2950 1166:0009 PCI IDs, for example by executing 2951 lspci -nn | grep '1166:0009' 2952 The code is inactive if there is none. 2953 2954 There's no public spec for this chipset, and this functionality 2955 is known to be incomplete. 2956 2957 You should say N unless you know you need this. 2958 2959config ISA_BUS 2960 bool "ISA bus support on modern systems" if EXPERT 2961 help 2962 Expose ISA bus device drivers and options available for selection and 2963 configuration. Enable this option if your target machine has an ISA 2964 bus. ISA is an older system, displaced by PCI and newer bus 2965 architectures -- if your target machine is modern, it probably does 2966 not have an ISA bus. 2967 2968 If unsure, say N. 2969 2970# x86_64 have no ISA slots, but can have ISA-style DMA. 2971config ISA_DMA_API 2972 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2973 default y 2974 help 2975 Enables ISA-style DMA support for devices requiring such controllers. 2976 If unsure, say Y. 2977 2978if X86_32 2979 2980config ISA 2981 bool "ISA support" 2982 help 2983 Find out whether you have ISA slots on your motherboard. ISA is the 2984 name of a bus system, i.e. the way the CPU talks to the other stuff 2985 inside your box. Other bus systems are PCI, EISA, MicroChannel 2986 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2987 newer boards don't support it. If you have ISA, say Y, otherwise N. 2988 2989config SCx200 2990 tristate "NatSemi SCx200 support" 2991 help 2992 This provides basic support for National Semiconductor's 2993 (now AMD's) Geode processors. The driver probes for the 2994 PCI-IDs of several on-chip devices, so its a good dependency 2995 for other scx200_* drivers. 2996 2997 If compiled as a module, the driver is named scx200. 2998 2999config SCx200HR_TIMER 3000 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 3001 depends on SCx200 3002 default y 3003 help 3004 This driver provides a clocksource built upon the on-chip 3005 27MHz high-resolution timer. Its also a workaround for 3006 NSC Geode SC-1100's buggy TSC, which loses time when the 3007 processor goes idle (as is done by the scheduler). The 3008 other workaround is idle=poll boot option. 3009 3010config OLPC 3011 bool "One Laptop Per Child support" 3012 depends on !X86_PAE 3013 select GPIOLIB 3014 select OF 3015 select OF_PROMTREE 3016 select IRQ_DOMAIN 3017 select OLPC_EC 3018 help 3019 Add support for detecting the unique features of the OLPC 3020 XO hardware. 3021 3022config OLPC_XO1_PM 3023 bool "OLPC XO-1 Power Management" 3024 depends on OLPC && MFD_CS5535=y && PM_SLEEP 3025 help 3026 Add support for poweroff and suspend of the OLPC XO-1 laptop. 3027 3028config OLPC_XO1_RTC 3029 bool "OLPC XO-1 Real Time Clock" 3030 depends on OLPC_XO1_PM && RTC_DRV_CMOS 3031 help 3032 Add support for the XO-1 real time clock, which can be used as a 3033 programmable wakeup source. 3034 3035config OLPC_XO1_SCI 3036 bool "OLPC XO-1 SCI extras" 3037 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 3038 depends on INPUT=y 3039 select POWER_SUPPLY 3040 help 3041 Add support for SCI-based features of the OLPC XO-1 laptop: 3042 - EC-driven system wakeups 3043 - Power button 3044 - Ebook switch 3045 - Lid switch 3046 - AC adapter status updates 3047 - Battery status updates 3048 3049config OLPC_XO15_SCI 3050 bool "OLPC XO-1.5 SCI extras" 3051 depends on OLPC && ACPI 3052 select POWER_SUPPLY 3053 help 3054 Add support for SCI-based features of the OLPC XO-1.5 laptop: 3055 - EC-driven system wakeups 3056 - AC adapter status updates 3057 - Battery status updates 3058 3059config GEODE_COMMON 3060 bool 3061 3062config ALIX 3063 bool "PCEngines ALIX System Support (LED setup)" 3064 select GPIOLIB 3065 select GEODE_COMMON 3066 help 3067 This option enables system support for the PCEngines ALIX. 3068 At present this just sets up LEDs for GPIO control on 3069 ALIX2/3/6 boards. However, other system specific setup should 3070 get added here. 3071 3072 Note: You must still enable the drivers for GPIO and LED support 3073 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 3074 3075 Note: You have to set alix.force=1 for boards with Award BIOS. 3076 3077config NET5501 3078 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 3079 select GPIOLIB 3080 select GEODE_COMMON 3081 help 3082 This option enables system support for the Soekris Engineering net5501. 3083 3084config GEOS 3085 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 3086 select GPIOLIB 3087 select GEODE_COMMON 3088 depends on DMI 3089 help 3090 This option enables system support for the Traverse Technologies GEOS. 3091 3092config TS5500 3093 bool "Technologic Systems TS-5500 platform support" 3094 depends on MELAN 3095 select CHECK_SIGNATURE 3096 select NEW_LEDS 3097 select LEDS_CLASS 3098 help 3099 This option enables system support for the Technologic Systems TS-5500. 3100 3101endif # X86_32 3102 3103config AMD_NB 3104 def_bool y 3105 depends on AMD_NODE 3106 3107config AMD_NODE 3108 def_bool y 3109 depends on CPU_SUP_AMD && PCI 3110 3111endmenu 3112 3113menu "Binary Emulations" 3114 3115config IA32_EMULATION 3116 bool "IA32 Emulation" 3117 depends on X86_64 3118 select ARCH_WANT_OLD_COMPAT_IPC 3119 select BINFMT_ELF 3120 select COMPAT_OLD_SIGACTION 3121 help 3122 Include code to run legacy 32-bit programs under a 3123 64-bit kernel. You should likely turn this on, unless you're 3124 100% sure that you don't have any 32-bit programs left. 3125 3126config IA32_EMULATION_DEFAULT_DISABLED 3127 bool "IA32 emulation disabled by default" 3128 default n 3129 depends on IA32_EMULATION 3130 help 3131 Make IA32 emulation disabled by default. This prevents loading 32-bit 3132 processes and access to 32-bit syscalls. If unsure, leave it to its 3133 default value. 3134 3135config X86_X32_ABI 3136 bool "x32 ABI for 64-bit mode" 3137 depends on X86_64 3138 # llvm-objcopy does not convert x86_64 .note.gnu.property or 3139 # compressed debug sections to x86_x32 properly: 3140 # https://github.com/ClangBuiltLinux/linux/issues/514 3141 # https://github.com/ClangBuiltLinux/linux/issues/1141 3142 depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm) 3143 help 3144 Include code to run binaries for the x32 native 32-bit ABI 3145 for 64-bit processors. An x32 process gets access to the 3146 full 64-bit register file and wide data path while leaving 3147 pointers at 32 bits for smaller memory footprint. 3148 3149config COMPAT_32 3150 def_bool y 3151 depends on IA32_EMULATION || X86_32 3152 select HAVE_UID16 3153 select OLD_SIGSUSPEND3 3154 3155config COMPAT 3156 def_bool y 3157 depends on IA32_EMULATION || X86_X32_ABI 3158 3159config COMPAT_FOR_U64_ALIGNMENT 3160 def_bool y 3161 depends on COMPAT 3162 3163endmenu 3164 3165config HAVE_ATOMIC_IOMAP 3166 def_bool y 3167 depends on X86_32 3168 3169source "arch/x86/kvm/Kconfig" 3170 3171source "arch/x86/Kconfig.cpufeatures" 3172 3173source "arch/x86/Kconfig.assembler" 3174