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 GENERIC_VDSO_32 18 select HAVE_DEBUG_STACKOVERFLOW 19 select KMAP_LOCAL 20 select MODULES_USE_ELF_REL 21 select OLD_SIGACTION 22 select ARCH_SPLIT_ARG64 23 24config X86_64 25 def_bool y 26 depends on 64BIT 27 # Options that are inherently 64-bit kernel only: 28 select ARCH_HAS_GIGANTIC_PAGE 29 select ARCH_HAS_PTDUMP 30 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 31 select ARCH_SUPPORTS_PER_VMA_LOCK 32 select ARCH_SUPPORTS_HUGE_PFNMAP if TRANSPARENT_HUGEPAGE 33 select HAVE_ARCH_SOFT_DIRTY 34 select MODULES_USE_ELF_RELA 35 select NEED_DMA_MAP_STATE 36 select SWIOTLB 37 select ARCH_HAS_ELFCORE_COMPAT 38 select ZONE_DMA32 39 select EXECMEM if DYNAMIC_FTRACE 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_MEMORY_HOTREMOVE if MEMORY_HOTPLUG 73 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE) 74 select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE 75 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 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_CRC32 81 select ARCH_HAS_CRC64 if X86_64 82 select ARCH_HAS_CRC_T10DIF 83 select ARCH_HAS_CURRENT_STACK_POINTER 84 select ARCH_HAS_DEBUG_VIRTUAL 85 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 86 select ARCH_HAS_DEVMEM_IS_ALLOWED 87 select ARCH_HAS_DMA_OPS if GART_IOMMU || XEN 88 select ARCH_HAS_EARLY_DEBUG if KGDB 89 select ARCH_HAS_ELF_RANDOMIZE 90 select ARCH_HAS_EXECMEM_ROX if X86_64 91 select ARCH_HAS_FAST_MULTIPLIER 92 select ARCH_HAS_FORTIFY_SOURCE 93 select ARCH_HAS_GCOV_PROFILE_ALL 94 select ARCH_HAS_KCOV if X86_64 95 select ARCH_HAS_KERNEL_FPU_SUPPORT 96 select ARCH_HAS_MEM_ENCRYPT 97 select ARCH_HAS_MEMBARRIER_SYNC_CORE 98 select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS 99 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 100 select ARCH_HAS_PMEM_API if X86_64 101 select ARCH_HAS_PREEMPT_LAZY 102 select ARCH_HAS_PTE_DEVMAP if X86_64 103 select ARCH_HAS_PTE_SPECIAL 104 select ARCH_HAS_HW_PTE_YOUNG 105 select ARCH_HAS_NONLEAF_PMD_YOUNG if PGTABLE_LEVELS > 2 106 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 107 select ARCH_HAS_COPY_MC if X86_64 108 select ARCH_HAS_SET_MEMORY 109 select ARCH_HAS_SET_DIRECT_MAP 110 select ARCH_HAS_STRICT_KERNEL_RWX 111 select ARCH_HAS_STRICT_MODULE_RWX 112 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 113 select ARCH_HAS_SYSCALL_WRAPPER 114 select ARCH_HAS_UBSAN 115 select ARCH_HAS_DEBUG_WX 116 select ARCH_HAS_ZONE_DMA_SET if EXPERT 117 select ARCH_HAVE_NMI_SAFE_CMPXCHG 118 select ARCH_HAVE_EXTRA_ELF_NOTES 119 select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 120 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 121 select ARCH_MIGHT_HAVE_PC_PARPORT 122 select ARCH_MIGHT_HAVE_PC_SERIO 123 select ARCH_STACKWALK 124 select ARCH_SUPPORTS_ACPI 125 select ARCH_SUPPORTS_ATOMIC_RMW 126 select ARCH_SUPPORTS_DEBUG_PAGEALLOC 127 select ARCH_SUPPORTS_PAGE_TABLE_CHECK if X86_64 128 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 129 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 130 select ARCH_SUPPORTS_CFI_CLANG if X86_64 131 select ARCH_USES_CFI_TRAPS if X86_64 && CFI_CLANG 132 select ARCH_SUPPORTS_LTO_CLANG 133 select ARCH_SUPPORTS_LTO_CLANG_THIN 134 select ARCH_SUPPORTS_RT 135 select ARCH_SUPPORTS_AUTOFDO_CLANG 136 select ARCH_SUPPORTS_PROPELLER_CLANG if X86_64 137 select ARCH_USE_BUILTIN_BSWAP 138 select ARCH_USE_CMPXCHG_LOCKREF if X86_CX8 139 select ARCH_USE_MEMTEST 140 select ARCH_USE_QUEUED_RWLOCKS 141 select ARCH_USE_QUEUED_SPINLOCKS 142 select ARCH_USE_SYM_ANNOTATIONS 143 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 144 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 145 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 146 select ARCH_WANTS_NO_INSTR 147 select ARCH_WANT_GENERAL_HUGETLB 148 select ARCH_WANT_HUGE_PMD_SHARE 149 select ARCH_WANT_LD_ORPHAN_WARN 150 select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP if X86_64 151 select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP if X86_64 152 select ARCH_WANT_HUGETLB_VMEMMAP_PREINIT if X86_64 153 select ARCH_WANTS_THP_SWAP if X86_64 154 select ARCH_HAS_PARANOID_L1D_FLUSH 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_MIN_ADJUST 167 select GENERIC_CMOS_UPDATE 168 select GENERIC_CPU_AUTOPROBE 169 select GENERIC_CPU_DEVICES 170 select GENERIC_CPU_VULNERABILITIES 171 select GENERIC_EARLY_IOREMAP 172 select GENERIC_ENTRY 173 select GENERIC_IOMAP 174 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 175 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 176 select GENERIC_IRQ_MIGRATION if SMP 177 select GENERIC_IRQ_PROBE 178 select GENERIC_IRQ_RESERVATION_MODE 179 select GENERIC_IRQ_SHOW 180 select GENERIC_PENDING_IRQ if SMP 181 select GENERIC_SMP_IDLE_THREAD 182 select GENERIC_TIME_VSYSCALL 183 select GENERIC_GETTIMEOFDAY 184 select GENERIC_VDSO_DATA_STORE 185 select GENERIC_VDSO_TIME_NS 186 select GENERIC_VDSO_OVERFLOW_PROTECT 187 select GUP_GET_PXX_LOW_HIGH if X86_PAE 188 select HARDIRQS_SW_RESEND 189 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 190 select HAS_IOPORT 191 select HAVE_ACPI_APEI if ACPI 192 select HAVE_ACPI_APEI_NMI if ACPI 193 select HAVE_ALIGNED_STRUCT_PAGE 194 select HAVE_ARCH_AUDITSYSCALL 195 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 196 select HAVE_ARCH_HUGE_VMALLOC if X86_64 197 select HAVE_ARCH_JUMP_LABEL 198 select HAVE_ARCH_JUMP_LABEL_RELATIVE 199 select HAVE_ARCH_KASAN if X86_64 200 select HAVE_ARCH_KASAN_VMALLOC if X86_64 201 select HAVE_ARCH_KFENCE 202 select HAVE_ARCH_KMSAN if X86_64 203 select HAVE_ARCH_KGDB 204 select HAVE_ARCH_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_STACKLEAK 211 select HAVE_ARCH_TRACEHOOK 212 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 213 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 214 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 215 select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 216 select HAVE_ARCH_VMAP_STACK if X86_64 217 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 218 select HAVE_ARCH_WITHIN_STACK_FRAMES 219 select HAVE_ASM_MODVERSIONS 220 select HAVE_CMPXCHG_DOUBLE 221 select HAVE_CMPXCHG_LOCAL 222 select HAVE_CONTEXT_TRACKING_USER if X86_64 223 select HAVE_CONTEXT_TRACKING_USER_OFFSTACK if HAVE_CONTEXT_TRACKING_USER 224 select HAVE_C_RECORDMCOUNT 225 select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL 226 select HAVE_OBJTOOL_NOP_MCOUNT if HAVE_OBJTOOL_MCOUNT 227 select HAVE_BUILDTIME_MCOUNT_SORT 228 select HAVE_DEBUG_KMEMLEAK 229 select HAVE_DMA_CONTIGUOUS 230 select HAVE_DYNAMIC_FTRACE 231 select HAVE_DYNAMIC_FTRACE_WITH_REGS 232 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 233 select HAVE_FTRACE_REGS_HAVING_PT_REGS if X86_64 234 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 235 select HAVE_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_GUP_FAST 242 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 243 select HAVE_FTRACE_GRAPH_FUNC if HAVE_FUNCTION_GRAPH_TRACER 244 select HAVE_FTRACE_MCOUNT_RECORD 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_LIVEPATCH if X86_64 267 select HAVE_MIXED_BREAKPOINTS_REGS 268 select HAVE_MOD_ARCH_SPECIFIC 269 select HAVE_MOVE_PMD 270 select HAVE_MOVE_PUD 271 select HAVE_NOINSTR_HACK if HAVE_OBJTOOL 272 select HAVE_NMI 273 select HAVE_NOINSTR_VALIDATION if HAVE_OBJTOOL 274 select HAVE_OBJTOOL if X86_64 275 select HAVE_OPTPROBES 276 select HAVE_PAGE_SIZE_4KB 277 select HAVE_PCSPKR_PLATFORM 278 select HAVE_PERF_EVENTS 279 select HAVE_PERF_EVENTS_NMI 280 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 281 select HAVE_PCI 282 select HAVE_PERF_REGS 283 select HAVE_PERF_USER_STACK_DUMP 284 select MMU_GATHER_RCU_TABLE_FREE 285 select MMU_GATHER_MERGE_VMAS 286 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 287 select HAVE_REGS_AND_STACK_ACCESS_API 288 select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC || STACK_VALIDATION 289 select HAVE_FUNCTION_ARG_ACCESS_API 290 select HAVE_SETUP_PER_CPU_AREA 291 select HAVE_SOFTIRQ_ON_OWN_STACK 292 select HAVE_STACKPROTECTOR 293 select HAVE_STACK_VALIDATION if HAVE_OBJTOOL 294 select HAVE_STATIC_CALL 295 select HAVE_STATIC_CALL_INLINE if HAVE_OBJTOOL 296 select HAVE_PREEMPT_DYNAMIC_CALL 297 select HAVE_RSEQ 298 select HAVE_RUST if X86_64 299 select HAVE_SYSCALL_TRACEPOINTS 300 select HAVE_UACCESS_VALIDATION if HAVE_OBJTOOL 301 select HAVE_UNSTABLE_SCHED_CLOCK 302 select HAVE_USER_RETURN_NOTIFIER 303 select HAVE_GENERIC_VDSO 304 select VDSO_GETRANDOM if X86_64 305 select HOTPLUG_PARALLEL if SMP && X86_64 306 select HOTPLUG_SMT if SMP 307 select HOTPLUG_SPLIT_STARTUP if SMP && X86_32 308 select IRQ_FORCED_THREADING 309 select LOCK_MM_AND_FIND_VMA 310 select NEED_PER_CPU_EMBED_FIRST_CHUNK 311 select NEED_PER_CPU_PAGE_FIRST_CHUNK 312 select NEED_SG_DMA_LENGTH 313 select NUMA_MEMBLKS if NUMA 314 select PCI_DOMAINS if PCI 315 select PCI_LOCKLESS_CONFIG if PCI 316 select PERF_EVENTS 317 select RTC_LIB 318 select RTC_MC146818_LIB 319 select SPARSE_IRQ 320 select SYSCTL_EXCEPTION_TRACE 321 select THREAD_INFO_IN_TASK 322 select TRACE_IRQFLAGS_SUPPORT 323 select TRACE_IRQFLAGS_NMI_SUPPORT 324 select USER_STACKTRACE_SUPPORT 325 select HAVE_ARCH_KCSAN if X86_64 326 select PROC_PID_ARCH_STATUS if PROC_FS 327 select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX 328 select FUNCTION_ALIGNMENT_16B if X86_64 || X86_ALIGNMENT_16 329 select FUNCTION_ALIGNMENT_4B 330 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 331 select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 332 select ARCH_SUPPORTS_PT_RECLAIM if X86_64 333 334config INSTRUCTION_DECODER 335 def_bool y 336 depends on KPROBES || PERF_EVENTS || UPROBES 337 338config OUTPUT_FORMAT 339 string 340 default "elf32-i386" if X86_32 341 default "elf64-x86-64" if X86_64 342 343config LOCKDEP_SUPPORT 344 def_bool y 345 346config STACKTRACE_SUPPORT 347 def_bool y 348 349config MMU 350 def_bool y 351 352config ARCH_MMAP_RND_BITS_MIN 353 default 28 if 64BIT 354 default 8 355 356config ARCH_MMAP_RND_BITS_MAX 357 default 32 if 64BIT 358 default 16 359 360config ARCH_MMAP_RND_COMPAT_BITS_MIN 361 default 8 362 363config ARCH_MMAP_RND_COMPAT_BITS_MAX 364 default 16 365 366config SBUS 367 bool 368 369config GENERIC_ISA_DMA 370 def_bool y 371 depends on ISA_DMA_API 372 373config GENERIC_CSUM 374 bool 375 default y if KMSAN || KASAN 376 377config GENERIC_BUG 378 def_bool y 379 depends on BUG 380 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 381 382config GENERIC_BUG_RELATIVE_POINTERS 383 bool 384 385config ARCH_MAY_HAVE_PC_FDC 386 def_bool y 387 depends on ISA_DMA_API 388 389config GENERIC_CALIBRATE_DELAY 390 def_bool y 391 392config ARCH_HAS_CPU_RELAX 393 def_bool y 394 395config ARCH_HIBERNATION_POSSIBLE 396 def_bool y 397 398config ARCH_SUSPEND_POSSIBLE 399 def_bool y 400 401config AUDIT_ARCH 402 def_bool y if X86_64 403 404config KASAN_SHADOW_OFFSET 405 hex 406 depends on KASAN 407 default 0xdffffc0000000000 408 409config HAVE_INTEL_TXT 410 def_bool y 411 depends on INTEL_IOMMU && ACPI 412 413config X86_64_SMP 414 def_bool y 415 depends on X86_64 && SMP 416 417config ARCH_SUPPORTS_UPROBES 418 def_bool y 419 420config FIX_EARLYCON_MEM 421 def_bool y 422 423config DYNAMIC_PHYSICAL_MASK 424 bool 425 426config PGTABLE_LEVELS 427 int 428 default 5 if X86_5LEVEL 429 default 4 if X86_64 430 default 3 if X86_PAE 431 default 2 432 433menu "Processor type and features" 434 435config SMP 436 bool "Symmetric multi-processing support" 437 help 438 This enables support for systems with more than one CPU. If you have 439 a system with only one CPU, say N. If you have a system with more 440 than one CPU, say Y. 441 442 If you say N here, the kernel will run on uni- and multiprocessor 443 machines, but will use only one CPU of a multiprocessor machine. If 444 you say Y here, the kernel will run on many, but not all, 445 uniprocessor machines. On a uniprocessor machine, the kernel 446 will run faster if you say N here. 447 448 Note that if you say Y here and choose architecture "586" or 449 "Pentium" under "Processor family", the kernel will not work on 486 450 architectures. Similarly, multiprocessor kernels for the "PPro" 451 architecture may not work on all Pentium based boards. 452 453 People using multiprocessor machines who say Y here should also say 454 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 455 Management" code will be disabled if you say Y here. 456 457 See also <file:Documentation/arch/x86/i386/IO-APIC.rst>, 458 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 459 <http://www.tldp.org/docs.html#howto>. 460 461 If you don't know what to do here, say N. 462 463config X86_X2APIC 464 bool "x2APIC interrupt controller architecture support" 465 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 466 default y 467 help 468 x2APIC is an interrupt controller architecture, a component of which 469 (the local APIC) is present in the CPU. It allows faster access to 470 the local APIC and supports a larger number of CPUs in the system 471 than the predecessors. 472 473 x2APIC was introduced in Intel CPUs around 2008 and in AMD EPYC CPUs 474 in 2019, but it can be disabled by the BIOS. It is also frequently 475 emulated in virtual machines, even when the host CPU does not support 476 it. Support in the CPU can be checked by executing 477 grep x2apic /proc/cpuinfo 478 479 If this configuration option is disabled, the kernel will boot with 480 very reduced functionality and performance on some platforms that 481 have x2APIC enabled. On the other hand, on hardware that does not 482 support x2APIC, a kernel with this option enabled will just fallback 483 to older APIC implementations. 484 485 If in doubt, say Y. 486 487config X86_POSTED_MSI 488 bool "Enable MSI and MSI-x delivery by posted interrupts" 489 depends on X86_64 && IRQ_REMAP 490 help 491 This enables MSIs that are under interrupt remapping to be delivered as 492 posted interrupts to the host kernel. Interrupt throughput can 493 potentially be improved by coalescing CPU notifications during high 494 frequency bursts. 495 496 If you don't know what to do here, say N. 497 498config X86_MPPARSE 499 bool "Enable MPS table" if ACPI 500 default y 501 depends on X86_LOCAL_APIC 502 help 503 For old smp systems that do not have proper acpi support. Newer systems 504 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 505 506config X86_CPU_RESCTRL 507 bool "x86 CPU resource control support" 508 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 509 select KERNFS 510 select PROC_CPU_RESCTRL if PROC_FS 511 select RESCTRL_FS_PSEUDO_LOCK 512 help 513 Enable x86 CPU resource control support. 514 515 Provide support for the allocation and monitoring of system resources 516 usage by the CPU. 517 518 Intel calls this Intel Resource Director Technology 519 (Intel(R) RDT). More information about RDT can be found in the 520 Intel x86 Architecture Software Developer Manual. 521 522 AMD calls this AMD Platform Quality of Service (AMD QoS). 523 More information about AMD QoS can be found in the AMD64 Technology 524 Platform Quality of Service Extensions manual. 525 526 Say N if unsure. 527 528config RESCTRL_FS_PSEUDO_LOCK 529 bool 530 help 531 Software mechanism to pin data in a cache portion using 532 micro-architecture specific knowledge. 533 534config X86_FRED 535 bool "Flexible Return and Event Delivery" 536 depends on X86_64 537 help 538 When enabled, try to use Flexible Return and Event Delivery 539 instead of the legacy SYSCALL/SYSENTER/IDT architecture for 540 ring transitions and exception/interrupt handling if the 541 system supports it. 542 543config X86_EXTENDED_PLATFORM 544 bool "Support for extended (non-PC) x86 platforms" 545 default y 546 help 547 If you disable this option then the kernel will only support 548 standard PC platforms. (which covers the vast majority of 549 systems out there.) 550 551 If you enable this option then you'll be able to select support 552 for the following non-PC x86 platforms, depending on the value of 553 CONFIG_64BIT. 554 555 32-bit platforms (CONFIG_64BIT=n): 556 Goldfish (mostly Android emulator) 557 Intel CE media processor (CE4100) SoC 558 Intel Quark 559 RDC R-321x SoC 560 561 64-bit platforms (CONFIG_64BIT=y): 562 Numascale NumaChip 563 ScaleMP vSMP 564 SGI Ultraviolet 565 Merrifield/Moorefield MID devices 566 Goldfish (mostly Android emulator) 567 568 If you have one of these systems, or if you want to build a 569 generic distribution kernel, say Y here - otherwise say N. 570 571# This is an alphabetically sorted list of 64 bit extended platforms 572# Please maintain the alphabetic order if and when there are additions 573config X86_NUMACHIP 574 bool "Numascale NumaChip" 575 depends on X86_64 576 depends on X86_EXTENDED_PLATFORM 577 depends on NUMA 578 depends on SMP 579 depends on X86_X2APIC 580 depends on PCI_MMCONFIG 581 help 582 Adds support for Numascale NumaChip large-SMP systems. Needed to 583 enable more than ~168 cores. 584 If you don't have one of these, you should say N here. 585 586config X86_VSMP 587 bool "ScaleMP vSMP" 588 select HYPERVISOR_GUEST 589 select PARAVIRT 590 depends on X86_64 && PCI 591 depends on X86_EXTENDED_PLATFORM 592 depends on SMP 593 help 594 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 595 supposed to run on these EM64T-based machines. Only choose this option 596 if you have one of these machines. 597 598config X86_UV 599 bool "SGI Ultraviolet" 600 depends on X86_64 601 depends on X86_EXTENDED_PLATFORM 602 depends on NUMA 603 depends on EFI 604 depends on KEXEC_CORE 605 depends on X86_X2APIC 606 depends on PCI 607 help 608 This option is needed in order to support SGI Ultraviolet systems. 609 If you don't have one of these, you should say N here. 610 611config X86_INTEL_MID 612 bool "Intel Z34xx/Z35xx MID platform support" 613 depends on X86_EXTENDED_PLATFORM 614 depends on X86_PLATFORM_DEVICES 615 depends on PCI 616 depends on X86_64 || (EXPERT && PCI_GOANY) 617 depends on X86_IO_APIC 618 select I2C 619 select DW_APB_TIMER 620 select INTEL_SCU_PCI 621 help 622 Select to build a kernel capable of supporting 64-bit Intel MID 623 (Mobile Internet Device) platform systems which do not have 624 the PCI legacy interfaces. 625 626 The only supported devices are the 22nm Merrified (Z34xx) 627 and Moorefield (Z35xx) SoC used in the Intel Edison board and 628 a small number of Android devices such as the Asus Zenfone 2, 629 Asus FonePad 8 and Dell Venue 7. 630 631 If you are building for a PC class system or non-MID tablet 632 SoCs like Bay Trail (Z36xx/Z37xx), say N here. 633 634 Intel MID platforms are based on an Intel processor and chipset which 635 consume less power than most of the x86 derivatives. 636 637config X86_GOLDFISH 638 bool "Goldfish (Virtual Platform)" 639 depends on X86_EXTENDED_PLATFORM 640 help 641 Enable support for the Goldfish virtual platform used primarily 642 for Android development. Unless you are building for the Android 643 Goldfish emulator say N here. 644 645# Following is an alphabetically sorted list of 32 bit extended platforms 646# Please maintain the alphabetic order if and when there are additions 647 648config X86_INTEL_CE 649 bool "CE4100 TV platform" 650 depends on PCI 651 depends on PCI_GODIRECT 652 depends on X86_IO_APIC 653 depends on X86_32 654 depends on X86_EXTENDED_PLATFORM 655 select X86_REBOOTFIXUPS 656 select OF 657 select OF_EARLY_FLATTREE 658 help 659 Select for the Intel CE media processor (CE4100) SOC. 660 This option compiles in support for the CE4100 SOC for settop 661 boxes and media devices. 662 663config X86_INTEL_QUARK 664 bool "Intel Quark platform support" 665 depends on X86_32 666 depends on X86_EXTENDED_PLATFORM 667 depends on X86_PLATFORM_DEVICES 668 depends on X86_TSC 669 depends on PCI 670 depends on PCI_GOANY 671 depends on X86_IO_APIC 672 select IOSF_MBI 673 select INTEL_IMR 674 select COMMON_CLK 675 help 676 Select to include support for Quark X1000 SoC. 677 Say Y here if you have a Quark based system such as the Arduino 678 compatible Intel Galileo. 679 680config X86_RDC321X 681 bool "RDC R-321x SoC" 682 depends on X86_32 683 depends on X86_EXTENDED_PLATFORM 684 select M486 685 select X86_REBOOTFIXUPS 686 help 687 This option is needed for RDC R-321x system-on-chip, also known 688 as R-8610-(G). 689 If you don't have one of these chips, you should say N here. 690 691config X86_INTEL_LPSS 692 bool "Intel Low Power Subsystem Support" 693 depends on X86 && ACPI && PCI 694 select COMMON_CLK 695 select PINCTRL 696 select IOSF_MBI 697 help 698 Select to build support for Intel Low Power Subsystem such as 699 found on Intel Lynxpoint PCH. Selecting this option enables 700 things like clock tree (common clock framework) and pincontrol 701 which are needed by the LPSS peripheral drivers. 702 703config X86_AMD_PLATFORM_DEVICE 704 bool "AMD ACPI2Platform devices support" 705 depends on ACPI 706 select COMMON_CLK 707 select PINCTRL 708 help 709 Select to interpret AMD specific ACPI device to platform device 710 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 711 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 712 implemented under PINCTRL subsystem. 713 714config IOSF_MBI 715 tristate "Intel SoC IOSF Sideband support for SoC platforms" 716 depends on PCI 717 help 718 This option enables sideband register access support for Intel SoC 719 platforms. On these platforms the IOSF sideband is used in lieu of 720 MSR's for some register accesses, mostly but not limited to thermal 721 and power. Drivers may query the availability of this device to 722 determine if they need the sideband in order to work on these 723 platforms. The sideband is available on the following SoC products. 724 This list is not meant to be exclusive. 725 - BayTrail 726 - Braswell 727 - Quark 728 729 You should say Y if you are running a kernel on one of these SoC's. 730 731config IOSF_MBI_DEBUG 732 bool "Enable IOSF sideband access through debugfs" 733 depends on IOSF_MBI && DEBUG_FS 734 help 735 Select this option to expose the IOSF sideband access registers (MCR, 736 MDR, MCRX) through debugfs to write and read register information from 737 different units on the SoC. This is most useful for obtaining device 738 state information for debug and analysis. As this is a general access 739 mechanism, users of this option would have specific knowledge of the 740 device they want to access. 741 742 If you don't require the option or are in doubt, say N. 743 744config X86_SUPPORTS_MEMORY_FAILURE 745 def_bool y 746 # MCE code calls memory_failure(): 747 depends on X86_MCE 748 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 749 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 750 depends on X86_64 || !SPARSEMEM 751 select ARCH_SUPPORTS_MEMORY_FAILURE 752 753config X86_32_IRIS 754 tristate "Eurobraille/Iris poweroff module" 755 depends on X86_32 756 help 757 The Iris machines from EuroBraille do not have APM or ACPI support 758 to shut themselves down properly. A special I/O sequence is 759 needed to do so, which is what this module does at 760 kernel shutdown. 761 762 This is only for Iris machines from EuroBraille. 763 764 If unused, say N. 765 766config SCHED_OMIT_FRAME_POINTER 767 def_bool y 768 prompt "Single-depth WCHAN output" 769 depends on X86 770 help 771 Calculate simpler /proc/<PID>/wchan values. If this option 772 is disabled then wchan values will recurse back to the 773 caller function. This provides more accurate wchan values, 774 at the expense of slightly more scheduling overhead. 775 776 If in doubt, say "Y". 777 778menuconfig HYPERVISOR_GUEST 779 bool "Linux guest support" 780 help 781 Say Y here to enable options for running Linux under various hyper- 782 visors. This option enables basic hypervisor detection and platform 783 setup. 784 785 If you say N, all options in this submenu will be skipped and 786 disabled, and Linux guest support won't be built in. 787 788if HYPERVISOR_GUEST 789 790config PARAVIRT 791 bool "Enable paravirtualization code" 792 depends on HAVE_STATIC_CALL 793 help 794 This changes the kernel so it can modify itself when it is run 795 under a hypervisor, potentially improving performance significantly 796 over full virtualization. However, when run without a hypervisor 797 the kernel is theoretically slower and slightly larger. 798 799config PARAVIRT_XXL 800 bool 801 802config PARAVIRT_DEBUG 803 bool "paravirt-ops debugging" 804 depends on PARAVIRT && DEBUG_KERNEL 805 help 806 Enable to debug paravirt_ops internals. Specifically, BUG if 807 a paravirt_op is missing when it is called. 808 809config PARAVIRT_SPINLOCKS 810 bool "Paravirtualization layer for spinlocks" 811 depends on PARAVIRT && SMP 812 help 813 Paravirtualized spinlocks allow a pvops backend to replace the 814 spinlock implementation with something virtualization-friendly 815 (for example, block the virtual CPU rather than spinning). 816 817 It has a minimal impact on native kernels and gives a nice performance 818 benefit on paravirtualized KVM / Xen kernels. 819 820 If you are unsure how to answer this question, answer Y. 821 822config X86_HV_CALLBACK_VECTOR 823 def_bool n 824 825source "arch/x86/xen/Kconfig" 826 827config KVM_GUEST 828 bool "KVM Guest support (including kvmclock)" 829 depends on PARAVIRT 830 select PARAVIRT_CLOCK 831 select ARCH_CPUIDLE_HALTPOLL 832 select X86_HV_CALLBACK_VECTOR 833 default y 834 help 835 This option enables various optimizations for running under the KVM 836 hypervisor. It includes a paravirtualized clock, so that instead 837 of relying on a PIT (or probably other) emulation by the 838 underlying device model, the host provides the guest with 839 timing infrastructure such as time of day, and system time 840 841config ARCH_CPUIDLE_HALTPOLL 842 def_bool n 843 prompt "Disable host haltpoll when loading haltpoll driver" 844 help 845 If virtualized under KVM, disable host haltpoll. 846 847config PVH 848 bool "Support for running PVH guests" 849 help 850 This option enables the PVH entry point for guest virtual machines 851 as specified in the x86/HVM direct boot ABI. 852 853config PARAVIRT_TIME_ACCOUNTING 854 bool "Paravirtual steal time accounting" 855 depends on PARAVIRT 856 help 857 Select this option to enable fine granularity task steal time 858 accounting. Time spent executing other tasks in parallel with 859 the current vCPU is discounted from the vCPU power. To account for 860 that, there can be a small performance impact. 861 862 If in doubt, say N here. 863 864config PARAVIRT_CLOCK 865 bool 866 867config JAILHOUSE_GUEST 868 bool "Jailhouse non-root cell support" 869 depends on X86_64 && PCI 870 select X86_PM_TIMER 871 help 872 This option allows to run Linux as guest in a Jailhouse non-root 873 cell. You can leave this option disabled if you only want to start 874 Jailhouse and run Linux afterwards in the root cell. 875 876config ACRN_GUEST 877 bool "ACRN Guest support" 878 depends on X86_64 879 select X86_HV_CALLBACK_VECTOR 880 help 881 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 882 a flexible, lightweight reference open-source hypervisor, built with 883 real-time and safety-criticality in mind. It is built for embedded 884 IOT with small footprint and real-time features. More details can be 885 found in https://projectacrn.org/. 886 887config INTEL_TDX_GUEST 888 bool "Intel TDX (Trust Domain Extensions) - Guest Support" 889 depends on X86_64 && CPU_SUP_INTEL 890 depends on X86_X2APIC 891 depends on EFI_STUB 892 select ARCH_HAS_CC_PLATFORM 893 select X86_MEM_ENCRYPT 894 select X86_MCE 895 select UNACCEPTED_MEMORY 896 help 897 Support running as a guest under Intel TDX. Without this support, 898 the guest kernel can not boot or run under TDX. 899 TDX includes memory encryption and integrity capabilities 900 which protect the confidentiality and integrity of guest 901 memory contents and CPU state. TDX guests are protected from 902 some attacks from the VMM. 903 904endif # HYPERVISOR_GUEST 905 906source "arch/x86/Kconfig.cpu" 907 908config HPET_TIMER 909 def_bool X86_64 910 prompt "HPET Timer Support" if X86_32 911 help 912 Use the IA-PC HPET (High Precision Event Timer) to manage 913 time in preference to the PIT and RTC, if a HPET is 914 present. 915 HPET is the next generation timer replacing legacy 8254s. 916 The HPET provides a stable time base on SMP 917 systems, unlike the TSC, but it is more expensive to access, 918 as it is off-chip. The interface used is documented 919 in the HPET spec, revision 1. 920 921 You can safely choose Y here. However, HPET will only be 922 activated if the platform and the BIOS support this feature. 923 Otherwise the 8254 will be used for timing services. 924 925 Choose N to continue using the legacy 8254 timer. 926 927config HPET_EMULATE_RTC 928 def_bool y 929 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 930 931# Mark as expert because too many people got it wrong. 932# The code disables itself when not needed. 933config DMI 934 default y 935 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 936 bool "Enable DMI scanning" if EXPERT 937 help 938 Enabled scanning of DMI to identify machine quirks. Say Y 939 here unless you have verified that your setup is not 940 affected by entries in the DMI blacklist. Required by PNP 941 BIOS code. 942 943config GART_IOMMU 944 bool "Old AMD GART IOMMU support" 945 select IOMMU_HELPER 946 select SWIOTLB 947 depends on X86_64 && PCI && AMD_NB 948 help 949 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 950 GART based hardware IOMMUs. 951 952 The GART supports full DMA access for devices with 32-bit access 953 limitations, on systems with more than 3 GB. This is usually needed 954 for USB, sound, many IDE/SATA chipsets and some other devices. 955 956 Newer systems typically have a modern AMD IOMMU, supported via 957 the CONFIG_AMD_IOMMU=y config option. 958 959 In normal configurations this driver is only active when needed: 960 there's more than 3 GB of memory and the system contains a 961 32-bit limited device. 962 963 If unsure, say Y. 964 965config BOOT_VESA_SUPPORT 966 bool 967 help 968 If true, at least one selected framebuffer driver can take advantage 969 of VESA video modes set at an early boot stage via the vga= parameter. 970 971config MAXSMP 972 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 973 depends on X86_64 && SMP && DEBUG_KERNEL 974 select CPUMASK_OFFSTACK 975 help 976 Enable maximum number of CPUS and NUMA Nodes for this architecture. 977 If unsure, say N. 978 979# 980# The maximum number of CPUs supported: 981# 982# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 983# and which can be configured interactively in the 984# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 985# 986# The ranges are different on 32-bit and 64-bit kernels, depending on 987# hardware capabilities and scalability features of the kernel. 988# 989# ( If MAXSMP is enabled we just use the highest possible value and disable 990# interactive configuration. ) 991# 992 993config NR_CPUS_RANGE_BEGIN 994 int 995 default NR_CPUS_RANGE_END if MAXSMP 996 default 1 if !SMP 997 default 2 998 999config NR_CPUS_RANGE_END 1000 int 1001 depends on X86_32 1002 default 8 if SMP 1003 default 1 if !SMP 1004 1005config NR_CPUS_RANGE_END 1006 int 1007 depends on X86_64 1008 default 8192 if SMP && CPUMASK_OFFSTACK 1009 default 512 if SMP && !CPUMASK_OFFSTACK 1010 default 1 if !SMP 1011 1012config NR_CPUS_DEFAULT 1013 int 1014 depends on X86_32 1015 default 8 if SMP 1016 default 1 if !SMP 1017 1018config NR_CPUS_DEFAULT 1019 int 1020 depends on X86_64 1021 default 8192 if MAXSMP 1022 default 64 if SMP 1023 default 1 if !SMP 1024 1025config NR_CPUS 1026 int "Maximum number of CPUs" if SMP && !MAXSMP 1027 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1028 default NR_CPUS_DEFAULT 1029 help 1030 This allows you to specify the maximum number of CPUs which this 1031 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1032 supported value is 8192, otherwise the maximum value is 512. The 1033 minimum value which makes sense is 2. 1034 1035 This is purely to save memory: each supported CPU adds about 8KB 1036 to the kernel image. 1037 1038config SCHED_CLUSTER 1039 bool "Cluster scheduler support" 1040 depends on SMP 1041 default y 1042 help 1043 Cluster scheduler support improves the CPU scheduler's decision 1044 making when dealing with machines that have clusters of CPUs. 1045 Cluster usually means a couple of CPUs which are placed closely 1046 by sharing mid-level caches, last-level cache tags or internal 1047 busses. 1048 1049config SCHED_SMT 1050 def_bool y if SMP 1051 1052config SCHED_MC 1053 def_bool y 1054 prompt "Multi-core scheduler support" 1055 depends on SMP 1056 help 1057 Multi-core scheduler support improves the CPU scheduler's decision 1058 making when dealing with multi-core CPU chips at a cost of slightly 1059 increased overhead in some places. If unsure say N here. 1060 1061config SCHED_MC_PRIO 1062 bool "CPU core priorities scheduler support" 1063 depends on SCHED_MC 1064 select X86_INTEL_PSTATE if CPU_SUP_INTEL 1065 select X86_AMD_PSTATE if CPU_SUP_AMD && ACPI 1066 select CPU_FREQ 1067 default y 1068 help 1069 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1070 core ordering determined at manufacturing time, which allows 1071 certain cores to reach higher turbo frequencies (when running 1072 single threaded workloads) than others. 1073 1074 Enabling this kernel feature teaches the scheduler about 1075 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1076 scheduler's CPU selection logic accordingly, so that higher 1077 overall system performance can be achieved. 1078 1079 This feature will have no effect on CPUs without this feature. 1080 1081 If unsure say Y here. 1082 1083config UP_LATE_INIT 1084 def_bool y 1085 depends on !SMP && X86_LOCAL_APIC 1086 1087config X86_UP_APIC 1088 bool "Local APIC support on uniprocessors" if !PCI_MSI 1089 default PCI_MSI 1090 depends on X86_32 && !SMP 1091 help 1092 A local APIC (Advanced Programmable Interrupt Controller) is an 1093 integrated interrupt controller in the CPU. If you have a single-CPU 1094 system which has a processor with a local APIC, you can say Y here to 1095 enable and use it. If you say Y here even though your machine doesn't 1096 have a local APIC, then the kernel will still run with no slowdown at 1097 all. The local APIC supports CPU-generated self-interrupts (timer, 1098 performance counters), and the NMI watchdog which detects hard 1099 lockups. 1100 1101config X86_UP_IOAPIC 1102 bool "IO-APIC support on uniprocessors" 1103 depends on X86_UP_APIC 1104 help 1105 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1106 SMP-capable replacement for PC-style interrupt controllers. Most 1107 SMP systems and many recent uniprocessor systems have one. 1108 1109 If you have a single-CPU system with an IO-APIC, you can say Y here 1110 to use it. If you say Y here even though your machine doesn't have 1111 an IO-APIC, then the kernel will still run with no slowdown at all. 1112 1113config X86_LOCAL_APIC 1114 def_bool y 1115 depends on X86_64 || SMP || X86_UP_APIC || PCI_MSI 1116 select IRQ_DOMAIN_HIERARCHY 1117 1118config ACPI_MADT_WAKEUP 1119 def_bool y 1120 depends on X86_64 1121 depends on ACPI 1122 depends on SMP 1123 depends on X86_LOCAL_APIC 1124 1125config X86_IO_APIC 1126 def_bool y 1127 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1128 1129config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1130 bool "Reroute for broken boot IRQs" 1131 depends on X86_IO_APIC 1132 help 1133 This option enables a workaround that fixes a source of 1134 spurious interrupts. This is recommended when threaded 1135 interrupt handling is used on systems where the generation of 1136 superfluous "boot interrupts" cannot be disabled. 1137 1138 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1139 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1140 kernel does during interrupt handling). On chipsets where this 1141 boot IRQ generation cannot be disabled, this workaround keeps 1142 the original IRQ line masked so that only the equivalent "boot 1143 IRQ" is delivered to the CPUs. The workaround also tells the 1144 kernel to set up the IRQ handler on the boot IRQ line. In this 1145 way only one interrupt is delivered to the kernel. Otherwise 1146 the spurious second interrupt may cause the kernel to bring 1147 down (vital) interrupt lines. 1148 1149 Only affects "broken" chipsets. Interrupt sharing may be 1150 increased on these systems. 1151 1152config X86_MCE 1153 bool "Machine Check / overheating reporting" 1154 select GENERIC_ALLOCATOR 1155 default y 1156 help 1157 Machine Check support allows the processor to notify the 1158 kernel if it detects a problem (e.g. overheating, data corruption). 1159 The action the kernel takes depends on the severity of the problem, 1160 ranging from warning messages to halting the machine. 1161 1162config X86_MCELOG_LEGACY 1163 bool "Support for deprecated /dev/mcelog character device" 1164 depends on X86_MCE 1165 help 1166 Enable support for /dev/mcelog which is needed by the old mcelog 1167 userspace logging daemon. Consider switching to the new generation 1168 rasdaemon solution. 1169 1170config X86_MCE_INTEL 1171 def_bool y 1172 prompt "Intel MCE features" 1173 depends on X86_MCE && X86_LOCAL_APIC 1174 help 1175 Additional support for intel specific MCE features such as 1176 the thermal monitor. 1177 1178config X86_MCE_AMD 1179 def_bool y 1180 prompt "AMD MCE features" 1181 depends on X86_MCE && X86_LOCAL_APIC 1182 help 1183 Additional support for AMD specific MCE features such as 1184 the DRAM Error Threshold. 1185 1186config X86_ANCIENT_MCE 1187 bool "Support for old Pentium 5 / WinChip machine checks" 1188 depends on X86_32 && X86_MCE 1189 help 1190 Include support for machine check handling on old Pentium 5 or WinChip 1191 systems. These typically need to be enabled explicitly on the command 1192 line. 1193 1194config X86_MCE_THRESHOLD 1195 depends on X86_MCE_AMD || X86_MCE_INTEL 1196 def_bool y 1197 1198config X86_MCE_INJECT 1199 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1200 tristate "Machine check injector support" 1201 help 1202 Provide support for injecting machine checks for testing purposes. 1203 If you don't know what a machine check is and you don't do kernel 1204 QA it is safe to say n. 1205 1206source "arch/x86/events/Kconfig" 1207 1208config X86_LEGACY_VM86 1209 bool "Legacy VM86 support" 1210 depends on X86_32 1211 help 1212 This option allows user programs to put the CPU into V8086 1213 mode, which is an 80286-era approximation of 16-bit real mode. 1214 1215 Some very old versions of X and/or vbetool require this option 1216 for user mode setting. Similarly, DOSEMU will use it if 1217 available to accelerate real mode DOS programs. However, any 1218 recent version of DOSEMU, X, or vbetool should be fully 1219 functional even without kernel VM86 support, as they will all 1220 fall back to software emulation. Nevertheless, if you are using 1221 a 16-bit DOS program where 16-bit performance matters, vm86 1222 mode might be faster than emulation and you might want to 1223 enable this option. 1224 1225 Note that any app that works on a 64-bit kernel is unlikely to 1226 need this option, as 64-bit kernels don't, and can't, support 1227 V8086 mode. This option is also unrelated to 16-bit protected 1228 mode and is not needed to run most 16-bit programs under Wine. 1229 1230 Enabling this option increases the complexity of the kernel 1231 and slows down exception handling a tiny bit. 1232 1233 If unsure, say N here. 1234 1235config VM86 1236 bool 1237 default X86_LEGACY_VM86 1238 1239config X86_16BIT 1240 bool "Enable support for 16-bit segments" if EXPERT 1241 default y 1242 depends on MODIFY_LDT_SYSCALL 1243 help 1244 This option is required by programs like Wine to run 16-bit 1245 protected mode legacy code on x86 processors. Disabling 1246 this option saves about 300 bytes on i386, or around 6K text 1247 plus 16K runtime memory on x86-64, 1248 1249config X86_ESPFIX32 1250 def_bool y 1251 depends on X86_16BIT && X86_32 1252 1253config X86_ESPFIX64 1254 def_bool y 1255 depends on X86_16BIT && X86_64 1256 1257config X86_VSYSCALL_EMULATION 1258 bool "Enable vsyscall emulation" if EXPERT 1259 default y 1260 depends on X86_64 1261 help 1262 This enables emulation of the legacy vsyscall page. Disabling 1263 it is roughly equivalent to booting with vsyscall=none, except 1264 that it will also disable the helpful warning if a program 1265 tries to use a vsyscall. With this option set to N, offending 1266 programs will just segfault, citing addresses of the form 1267 0xffffffffff600?00. 1268 1269 This option is required by many programs built before 2013, and 1270 care should be used even with newer programs if set to N. 1271 1272 Disabling this option saves about 7K of kernel size and 1273 possibly 4K of additional runtime pagetable memory. 1274 1275config X86_IOPL_IOPERM 1276 bool "IOPERM and IOPL Emulation" 1277 default y 1278 help 1279 This enables the ioperm() and iopl() syscalls which are necessary 1280 for legacy applications. 1281 1282 Legacy IOPL support is an overbroad mechanism which allows user 1283 space aside of accessing all 65536 I/O ports also to disable 1284 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1285 capabilities and permission from potentially active security 1286 modules. 1287 1288 The emulation restricts the functionality of the syscall to 1289 only allowing the full range I/O port access, but prevents the 1290 ability to disable interrupts from user space which would be 1291 granted if the hardware IOPL mechanism would be used. 1292 1293config TOSHIBA 1294 tristate "Toshiba Laptop support" 1295 depends on X86_32 1296 help 1297 This adds a driver to safely access the System Management Mode of 1298 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1299 not work on models with a Phoenix BIOS. The System Management Mode 1300 is used to set the BIOS and power saving options on Toshiba portables. 1301 1302 For information on utilities to make use of this driver see the 1303 Toshiba Linux utilities web site at: 1304 <http://www.buzzard.org.uk/toshiba/>. 1305 1306 Say Y if you intend to run this kernel on a Toshiba portable. 1307 Say N otherwise. 1308 1309config X86_REBOOTFIXUPS 1310 bool "Enable X86 board specific fixups for reboot" 1311 depends on X86_32 1312 help 1313 This enables chipset and/or board specific fixups to be done 1314 in order to get reboot to work correctly. This is only needed on 1315 some combinations of hardware and BIOS. The symptom, for which 1316 this config is intended, is when reboot ends with a stalled/hung 1317 system. 1318 1319 Currently, the only fixup is for the Geode machines using 1320 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1321 1322 Say Y if you want to enable the fixup. Currently, it's safe to 1323 enable this option even if you don't need it. 1324 Say N otherwise. 1325 1326config MICROCODE 1327 def_bool y 1328 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1329 select CRYPTO_LIB_SHA256 if CPU_SUP_AMD 1330 1331config MICROCODE_INITRD32 1332 def_bool y 1333 depends on MICROCODE && X86_32 && BLK_DEV_INITRD 1334 1335config MICROCODE_LATE_LOADING 1336 bool "Late microcode loading (DANGEROUS)" 1337 default n 1338 depends on MICROCODE && SMP 1339 help 1340 Loading microcode late, when the system is up and executing instructions 1341 is a tricky business and should be avoided if possible. Just the sequence 1342 of synchronizing all cores and SMT threads is one fragile dance which does 1343 not guarantee that cores might not softlock after the loading. Therefore, 1344 use this at your own risk. Late loading taints the kernel unless the 1345 microcode header indicates that it is safe for late loading via the 1346 minimal revision check. This minimal revision check can be enforced on 1347 the kernel command line with "microcode.minrev=Y". 1348 1349config MICROCODE_LATE_FORCE_MINREV 1350 bool "Enforce late microcode loading minimal revision check" 1351 default n 1352 depends on MICROCODE_LATE_LOADING 1353 help 1354 To prevent that users load microcode late which modifies already 1355 in use features, newer microcode patches have a minimum revision field 1356 in the microcode header, which tells the kernel which minimum 1357 revision must be active in the CPU to safely load that new microcode 1358 late into the running system. If disabled the check will not 1359 be enforced but the kernel will be tainted when the minimal 1360 revision check fails. 1361 1362 This minimal revision check can also be controlled via the 1363 "microcode.minrev" parameter on the kernel command line. 1364 1365 If unsure say Y. 1366 1367config X86_MSR 1368 tristate "/dev/cpu/*/msr - Model-specific register support" 1369 help 1370 This device gives privileged processes access to the x86 1371 Model-Specific Registers (MSRs). It is a character device with 1372 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1373 MSR accesses are directed to a specific CPU on multi-processor 1374 systems. 1375 1376config X86_CPUID 1377 tristate "/dev/cpu/*/cpuid - CPU information support" 1378 help 1379 This device gives processes access to the x86 CPUID instruction to 1380 be executed on a specific processor. It is a character device 1381 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1382 /dev/cpu/31/cpuid. 1383 1384config HIGHMEM4G 1385 bool "High Memory Support" 1386 depends on X86_32 1387 help 1388 Linux can use up to 4 Gigabytes of physical memory on x86 systems. 1389 However, the address space of 32-bit x86 processors is only 4 1390 Gigabytes large. That means that, if you have a large amount of 1391 physical memory, not all of it can be "permanently mapped" by the 1392 kernel. The physical memory that's not permanently mapped is called 1393 "high memory". 1394 1395 If you are compiling a kernel which will never run on a machine with 1396 more than 1 Gigabyte total physical RAM, answer "off" here (default 1397 choice and suitable for most users). This will result in a "3GB/1GB" 1398 split: 3GB are mapped so that each process sees a 3GB virtual memory 1399 space and the remaining part of the 4GB virtual memory space is used 1400 by the kernel to permanently map as much physical memory as 1401 possible. 1402 1403 If the machine has between 1 and 4 Gigabytes physical RAM, then 1404 answer "Y" here. 1405 1406 If unsure, say N. 1407 1408choice 1409 prompt "Memory split" if EXPERT 1410 default VMSPLIT_3G 1411 depends on X86_32 1412 help 1413 Select the desired split between kernel and user memory. 1414 1415 If the address range available to the kernel is less than the 1416 physical memory installed, the remaining memory will be available 1417 as "high memory". Accessing high memory is a little more costly 1418 than low memory, as it needs to be mapped into the kernel first. 1419 Note that increasing the kernel address space limits the range 1420 available to user programs, making the address space there 1421 tighter. Selecting anything other than the default 3G/1G split 1422 will also likely make your kernel incompatible with binary-only 1423 kernel modules. 1424 1425 If you are not absolutely sure what you are doing, leave this 1426 option alone! 1427 1428 config VMSPLIT_3G 1429 bool "3G/1G user/kernel split" 1430 config VMSPLIT_3G_OPT 1431 depends on !X86_PAE 1432 bool "3G/1G user/kernel split (for full 1G low memory)" 1433 config VMSPLIT_2G 1434 bool "2G/2G user/kernel split" 1435 config VMSPLIT_2G_OPT 1436 depends on !X86_PAE 1437 bool "2G/2G user/kernel split (for full 2G low memory)" 1438 config VMSPLIT_1G 1439 bool "1G/3G user/kernel split" 1440endchoice 1441 1442config PAGE_OFFSET 1443 hex 1444 default 0xB0000000 if VMSPLIT_3G_OPT 1445 default 0x80000000 if VMSPLIT_2G 1446 default 0x78000000 if VMSPLIT_2G_OPT 1447 default 0x40000000 if VMSPLIT_1G 1448 default 0xC0000000 1449 depends on X86_32 1450 1451config HIGHMEM 1452 def_bool HIGHMEM4G 1453 1454config X86_PAE 1455 bool "PAE (Physical Address Extension) Support" 1456 depends on X86_32 && X86_HAVE_PAE 1457 select PHYS_ADDR_T_64BIT 1458 help 1459 PAE is required for NX support, and furthermore enables 1460 larger swapspace support for non-overcommit purposes. It 1461 has the cost of more pagetable lookup overhead, and also 1462 consumes more pagetable space per process. 1463 1464config X86_5LEVEL 1465 bool "Enable 5-level page tables support" 1466 default y 1467 select DYNAMIC_MEMORY_LAYOUT 1468 select SPARSEMEM_VMEMMAP 1469 depends on X86_64 1470 help 1471 5-level paging enables access to larger address space: 1472 up to 128 PiB of virtual address space and 4 PiB of 1473 physical address space. 1474 1475 It will be supported by future Intel CPUs. 1476 1477 A kernel with the option enabled can be booted on machines that 1478 support 4- or 5-level paging. 1479 1480 See Documentation/arch/x86/x86_64/5level-paging.rst for more 1481 information. 1482 1483 Say N if unsure. 1484 1485config X86_DIRECT_GBPAGES 1486 def_bool y 1487 depends on X86_64 1488 help 1489 Certain kernel features effectively disable kernel 1490 linear 1 GB mappings (even if the CPU otherwise 1491 supports them), so don't confuse the user by printing 1492 that we have them enabled. 1493 1494config X86_CPA_STATISTICS 1495 bool "Enable statistic for Change Page Attribute" 1496 depends on DEBUG_FS 1497 help 1498 Expose statistics about the Change Page Attribute mechanism, which 1499 helps to determine the effectiveness of preserving large and huge 1500 page mappings when mapping protections are changed. 1501 1502config X86_MEM_ENCRYPT 1503 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1504 select DYNAMIC_PHYSICAL_MASK 1505 def_bool n 1506 1507config AMD_MEM_ENCRYPT 1508 bool "AMD Secure Memory Encryption (SME) support" 1509 depends on X86_64 && CPU_SUP_AMD 1510 depends on EFI_STUB 1511 select DMA_COHERENT_POOL 1512 select ARCH_USE_MEMREMAP_PROT 1513 select INSTRUCTION_DECODER 1514 select ARCH_HAS_CC_PLATFORM 1515 select X86_MEM_ENCRYPT 1516 select UNACCEPTED_MEMORY 1517 select CRYPTO_LIB_AESGCM 1518 help 1519 Say yes to enable support for the encryption of system memory. 1520 This requires an AMD processor that supports Secure Memory 1521 Encryption (SME). 1522 1523# Common NUMA Features 1524config NUMA 1525 bool "NUMA Memory Allocation and Scheduler Support" 1526 depends on SMP 1527 depends on X86_64 1528 select USE_PERCPU_NUMA_NODE_ID 1529 select OF_NUMA if OF 1530 help 1531 Enable NUMA (Non-Uniform Memory Access) support. 1532 1533 The kernel will try to allocate memory used by a CPU on the 1534 local memory controller of the CPU and add some more 1535 NUMA awareness to the kernel. 1536 1537 For 64-bit this is recommended if the system is Intel Core i7 1538 (or later), AMD Opteron, or EM64T NUMA. 1539 1540 Otherwise, you should say N. 1541 1542config AMD_NUMA 1543 def_bool y 1544 prompt "Old style AMD Opteron NUMA detection" 1545 depends on X86_64 && NUMA && PCI 1546 help 1547 Enable AMD NUMA node topology detection. You should say Y here if 1548 you have a multi processor AMD system. This uses an old method to 1549 read the NUMA configuration directly from the builtin Northbridge 1550 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1551 which also takes priority if both are compiled in. 1552 1553config X86_64_ACPI_NUMA 1554 def_bool y 1555 prompt "ACPI NUMA detection" 1556 depends on X86_64 && NUMA && ACPI && PCI 1557 select ACPI_NUMA 1558 help 1559 Enable ACPI SRAT based node topology detection. 1560 1561config NODES_SHIFT 1562 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1563 range 1 10 1564 default "10" if MAXSMP 1565 default "6" if X86_64 1566 default "3" 1567 depends on NUMA 1568 help 1569 Specify the maximum number of NUMA Nodes available on the target 1570 system. Increases memory reserved to accommodate various tables. 1571 1572config ARCH_FLATMEM_ENABLE 1573 def_bool y 1574 depends on X86_32 && !NUMA 1575 1576config ARCH_SPARSEMEM_ENABLE 1577 def_bool y 1578 select SPARSEMEM_STATIC if X86_32 1579 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1580 1581config ARCH_SPARSEMEM_DEFAULT 1582 def_bool X86_64 || (NUMA && X86_32) 1583 1584config ARCH_SELECT_MEMORY_MODEL 1585 def_bool y 1586 depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE 1587 1588config ARCH_MEMORY_PROBE 1589 bool "Enable sysfs memory/probe interface" 1590 depends on MEMORY_HOTPLUG 1591 help 1592 This option enables a sysfs memory/probe interface for testing. 1593 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1594 If you are unsure how to answer this question, answer N. 1595 1596config ARCH_PROC_KCORE_TEXT 1597 def_bool y 1598 depends on X86_64 && PROC_KCORE 1599 1600config ILLEGAL_POINTER_VALUE 1601 hex 1602 default 0 if X86_32 1603 default 0xdead000000000000 if X86_64 1604 1605config X86_PMEM_LEGACY_DEVICE 1606 bool 1607 1608config X86_PMEM_LEGACY 1609 tristate "Support non-standard NVDIMMs and ADR protected memory" 1610 depends on PHYS_ADDR_T_64BIT 1611 depends on BLK_DEV 1612 select X86_PMEM_LEGACY_DEVICE 1613 select NUMA_KEEP_MEMINFO if NUMA 1614 select LIBNVDIMM 1615 help 1616 Treat memory marked using the non-standard e820 type of 12 as used 1617 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1618 The kernel will offer these regions to the 'pmem' driver so 1619 they can be used for persistent storage. 1620 1621 Say Y if unsure. 1622 1623config X86_CHECK_BIOS_CORRUPTION 1624 bool "Check for low memory corruption" 1625 help 1626 Periodically check for memory corruption in low memory, which 1627 is suspected to be caused by BIOS. Even when enabled in the 1628 configuration, it is disabled at runtime. Enable it by 1629 setting "memory_corruption_check=1" on the kernel command 1630 line. By default it scans the low 64k of memory every 60 1631 seconds; see the memory_corruption_check_size and 1632 memory_corruption_check_period parameters in 1633 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1634 1635 When enabled with the default parameters, this option has 1636 almost no overhead, as it reserves a relatively small amount 1637 of memory and scans it infrequently. It both detects corruption 1638 and prevents it from affecting the running system. 1639 1640 It is, however, intended as a diagnostic tool; if repeatable 1641 BIOS-originated corruption always affects the same memory, 1642 you can use memmap= to prevent the kernel from using that 1643 memory. 1644 1645config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1646 bool "Set the default setting of memory_corruption_check" 1647 depends on X86_CHECK_BIOS_CORRUPTION 1648 default y 1649 help 1650 Set whether the default state of memory_corruption_check is 1651 on or off. 1652 1653config MATH_EMULATION 1654 bool 1655 depends on MODIFY_LDT_SYSCALL 1656 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1657 help 1658 Linux can emulate a math coprocessor (used for floating point 1659 operations) if you don't have one. 486DX and Pentium processors have 1660 a math coprocessor built in, 486SX and 386 do not, unless you added 1661 a 487DX or 387, respectively. (The messages during boot time can 1662 give you some hints here ["man dmesg"].) Everyone needs either a 1663 coprocessor or this emulation. 1664 1665 If you don't have a math coprocessor, you need to say Y here; if you 1666 say Y here even though you have a coprocessor, the coprocessor will 1667 be used nevertheless. (This behavior can be changed with the kernel 1668 command line option "no387", which comes handy if your coprocessor 1669 is broken. Try "man bootparam" or see the documentation of your boot 1670 loader (lilo or loadlin) about how to pass options to the kernel at 1671 boot time.) This means that it is a good idea to say Y here if you 1672 intend to use this kernel on different machines. 1673 1674 More information about the internals of the Linux math coprocessor 1675 emulation can be found in <file:arch/x86/math-emu/README>. 1676 1677 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1678 kernel, it won't hurt. 1679 1680config MTRR 1681 def_bool y 1682 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1683 help 1684 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1685 the Memory Type Range Registers (MTRRs) may be used to control 1686 processor access to memory ranges. This is most useful if you have 1687 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1688 allows bus write transfers to be combined into a larger transfer 1689 before bursting over the PCI/AGP bus. This can increase performance 1690 of image write operations 2.5 times or more. Saying Y here creates a 1691 /proc/mtrr file which may be used to manipulate your processor's 1692 MTRRs. Typically the X server should use this. 1693 1694 This code has a reasonably generic interface so that similar 1695 control registers on other processors can be easily supported 1696 as well: 1697 1698 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1699 Registers (ARRs) which provide a similar functionality to MTRRs. For 1700 these, the ARRs are used to emulate the MTRRs. 1701 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1702 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1703 write-combining. All of these processors are supported by this code 1704 and it makes sense to say Y here if you have one of them. 1705 1706 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1707 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1708 can lead to all sorts of problems, so it's good to say Y here. 1709 1710 You can safely say Y even if your machine doesn't have MTRRs, you'll 1711 just add about 9 KB to your kernel. 1712 1713 See <file:Documentation/arch/x86/mtrr.rst> for more information. 1714 1715config MTRR_SANITIZER 1716 def_bool y 1717 prompt "MTRR cleanup support" 1718 depends on MTRR 1719 help 1720 Convert MTRR layout from continuous to discrete, so X drivers can 1721 add writeback entries. 1722 1723 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1724 The largest mtrr entry size for a continuous block can be set with 1725 mtrr_chunk_size. 1726 1727 If unsure, say Y. 1728 1729config MTRR_SANITIZER_ENABLE_DEFAULT 1730 int "MTRR cleanup enable value (0-1)" 1731 range 0 1 1732 default "0" 1733 depends on MTRR_SANITIZER 1734 help 1735 Enable mtrr cleanup default value 1736 1737config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1738 int "MTRR cleanup spare reg num (0-7)" 1739 range 0 7 1740 default "1" 1741 depends on MTRR_SANITIZER 1742 help 1743 mtrr cleanup spare entries default, it can be changed via 1744 mtrr_spare_reg_nr=N on the kernel command line. 1745 1746config X86_PAT 1747 def_bool y 1748 prompt "x86 PAT support" if EXPERT 1749 depends on MTRR 1750 select ARCH_USES_PG_ARCH_2 1751 help 1752 Use PAT attributes to setup page level cache control. 1753 1754 PATs are the modern equivalents of MTRRs and are much more 1755 flexible than MTRRs. 1756 1757 Say N here if you see bootup problems (boot crash, boot hang, 1758 spontaneous reboots) or a non-working video driver. 1759 1760 If unsure, say Y. 1761 1762config X86_UMIP 1763 def_bool y 1764 prompt "User Mode Instruction Prevention" if EXPERT 1765 help 1766 User Mode Instruction Prevention (UMIP) is a security feature in 1767 some x86 processors. If enabled, a general protection fault is 1768 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1769 executed in user mode. These instructions unnecessarily expose 1770 information about the hardware state. 1771 1772 The vast majority of applications do not use these instructions. 1773 For the very few that do, software emulation is provided in 1774 specific cases in protected and virtual-8086 modes. Emulated 1775 results are dummy. 1776 1777config CC_HAS_IBT 1778 # GCC >= 9 and binutils >= 2.29 1779 # Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654 1780 # Clang/LLVM >= 14 1781 # https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f 1782 # https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332 1783 def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \ 1784 (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \ 1785 $(as-instr,endbr64) 1786 1787config X86_CET 1788 def_bool n 1789 help 1790 CET features configured (Shadow stack or IBT) 1791 1792config X86_KERNEL_IBT 1793 prompt "Indirect Branch Tracking" 1794 def_bool y 1795 depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL 1796 # https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f 1797 depends on !LD_IS_LLD || LLD_VERSION >= 140000 1798 select OBJTOOL 1799 select X86_CET 1800 help 1801 Build the kernel with support for Indirect Branch Tracking, a 1802 hardware support course-grain forward-edge Control Flow Integrity 1803 protection. It enforces that all indirect calls must land on 1804 an ENDBR instruction, as such, the compiler will instrument the 1805 code with them to make this happen. 1806 1807 In addition to building the kernel with IBT, seal all functions that 1808 are not indirect call targets, avoiding them ever becoming one. 1809 1810 This requires LTO like objtool runs and will slow down the build. It 1811 does significantly reduce the number of ENDBR instructions in the 1812 kernel image. 1813 1814config X86_INTEL_MEMORY_PROTECTION_KEYS 1815 prompt "Memory Protection Keys" 1816 def_bool y 1817 # Note: only available in 64-bit mode 1818 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1819 select ARCH_USES_HIGH_VMA_FLAGS 1820 select ARCH_HAS_PKEYS 1821 help 1822 Memory Protection Keys provides a mechanism for enforcing 1823 page-based protections, but without requiring modification of the 1824 page tables when an application changes protection domains. 1825 1826 For details, see Documentation/core-api/protection-keys.rst 1827 1828 If unsure, say y. 1829 1830config ARCH_PKEY_BITS 1831 int 1832 default 4 1833 1834choice 1835 prompt "TSX enable mode" 1836 depends on CPU_SUP_INTEL 1837 default X86_INTEL_TSX_MODE_OFF 1838 help 1839 Intel's TSX (Transactional Synchronization Extensions) feature 1840 allows to optimize locking protocols through lock elision which 1841 can lead to a noticeable performance boost. 1842 1843 On the other hand it has been shown that TSX can be exploited 1844 to form side channel attacks (e.g. TAA) and chances are there 1845 will be more of those attacks discovered in the future. 1846 1847 Therefore TSX is not enabled by default (aka tsx=off). An admin 1848 might override this decision by tsx=on the command line parameter. 1849 Even with TSX enabled, the kernel will attempt to enable the best 1850 possible TAA mitigation setting depending on the microcode available 1851 for the particular machine. 1852 1853 This option allows to set the default tsx mode between tsx=on, =off 1854 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1855 details. 1856 1857 Say off if not sure, auto if TSX is in use but it should be used on safe 1858 platforms or on if TSX is in use and the security aspect of tsx is not 1859 relevant. 1860 1861config X86_INTEL_TSX_MODE_OFF 1862 bool "off" 1863 help 1864 TSX is disabled if possible - equals to tsx=off command line parameter. 1865 1866config X86_INTEL_TSX_MODE_ON 1867 bool "on" 1868 help 1869 TSX is always enabled on TSX capable HW - equals the tsx=on command 1870 line parameter. 1871 1872config X86_INTEL_TSX_MODE_AUTO 1873 bool "auto" 1874 help 1875 TSX is enabled on TSX capable HW that is believed to be safe against 1876 side channel attacks- equals the tsx=auto command line parameter. 1877endchoice 1878 1879config X86_SGX 1880 bool "Software Guard eXtensions (SGX)" 1881 depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC 1882 depends on CRYPTO=y 1883 depends on CRYPTO_SHA256=y 1884 select MMU_NOTIFIER 1885 select NUMA_KEEP_MEMINFO if NUMA 1886 select XARRAY_MULTI 1887 help 1888 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1889 that can be used by applications to set aside private regions of code 1890 and data, referred to as enclaves. An enclave's private memory can 1891 only be accessed by code running within the enclave. Accesses from 1892 outside the enclave, including other enclaves, are disallowed by 1893 hardware. 1894 1895 If unsure, say N. 1896 1897config X86_USER_SHADOW_STACK 1898 bool "X86 userspace shadow stack" 1899 depends on AS_WRUSS 1900 depends on X86_64 1901 select ARCH_USES_HIGH_VMA_FLAGS 1902 select ARCH_HAS_USER_SHADOW_STACK 1903 select X86_CET 1904 help 1905 Shadow stack protection is a hardware feature that detects function 1906 return address corruption. This helps mitigate ROP attacks. 1907 Applications must be enabled to use it, and old userspace does not 1908 get protection "for free". 1909 1910 CPUs supporting shadow stacks were first released in 2020. 1911 1912 See Documentation/arch/x86/shstk.rst for more information. 1913 1914 If unsure, say N. 1915 1916config INTEL_TDX_HOST 1917 bool "Intel Trust Domain Extensions (TDX) host support" 1918 depends on CPU_SUP_INTEL 1919 depends on X86_64 1920 depends on KVM_INTEL 1921 depends on X86_X2APIC 1922 select ARCH_KEEP_MEMBLOCK 1923 depends on CONTIG_ALLOC 1924 depends on !KEXEC_CORE 1925 depends on X86_MCE 1926 help 1927 Intel Trust Domain Extensions (TDX) protects guest VMs from malicious 1928 host and certain physical attacks. This option enables necessary TDX 1929 support in the host kernel to run confidential VMs. 1930 1931 If unsure, say N. 1932 1933config EFI 1934 bool "EFI runtime service support" 1935 depends on ACPI 1936 select UCS2_STRING 1937 select EFI_RUNTIME_WRAPPERS 1938 select ARCH_USE_MEMREMAP_PROT 1939 select EFI_RUNTIME_MAP if KEXEC_CORE 1940 help 1941 This enables the kernel to use EFI runtime services that are 1942 available (such as the EFI variable services). 1943 1944 This option is only useful on systems that have EFI firmware. 1945 In addition, you should use the latest ELILO loader available 1946 at <http://elilo.sourceforge.net> in order to take advantage 1947 of EFI runtime services. However, even with this option, the 1948 resultant kernel should continue to boot on existing non-EFI 1949 platforms. 1950 1951config EFI_STUB 1952 bool "EFI stub support" 1953 depends on EFI 1954 select RELOCATABLE 1955 help 1956 This kernel feature allows a bzImage to be loaded directly 1957 by EFI firmware without the use of a bootloader. 1958 1959 See Documentation/admin-guide/efi-stub.rst for more information. 1960 1961config EFI_HANDOVER_PROTOCOL 1962 bool "EFI handover protocol (DEPRECATED)" 1963 depends on EFI_STUB 1964 default y 1965 help 1966 Select this in order to include support for the deprecated EFI 1967 handover protocol, which defines alternative entry points into the 1968 EFI stub. This is a practice that has no basis in the UEFI 1969 specification, and requires a priori knowledge on the part of the 1970 bootloader about Linux/x86 specific ways of passing the command line 1971 and initrd, and where in memory those assets may be loaded. 1972 1973 If in doubt, say Y. Even though the corresponding support is not 1974 present in upstream GRUB or other bootloaders, most distros build 1975 GRUB with numerous downstream patches applied, and may rely on the 1976 handover protocol as as result. 1977 1978config EFI_MIXED 1979 bool "EFI mixed-mode support" 1980 depends on EFI_STUB && X86_64 1981 help 1982 Enabling this feature allows a 64-bit kernel to be booted 1983 on a 32-bit firmware, provided that your CPU supports 64-bit 1984 mode. 1985 1986 Note that it is not possible to boot a mixed-mode enabled 1987 kernel via the EFI boot stub - a bootloader that supports 1988 the EFI handover protocol must be used. 1989 1990 If unsure, say N. 1991 1992config EFI_RUNTIME_MAP 1993 bool "Export EFI runtime maps to sysfs" if EXPERT 1994 depends on EFI 1995 help 1996 Export EFI runtime memory regions to /sys/firmware/efi/runtime-map. 1997 That memory map is required by the 2nd kernel to set up EFI virtual 1998 mappings after kexec, but can also be used for debugging purposes. 1999 2000 See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map. 2001 2002source "kernel/Kconfig.hz" 2003 2004config ARCH_SUPPORTS_KEXEC 2005 def_bool y 2006 2007config ARCH_SUPPORTS_KEXEC_FILE 2008 def_bool X86_64 2009 2010config ARCH_SELECTS_KEXEC_FILE 2011 def_bool y 2012 depends on KEXEC_FILE 2013 select HAVE_IMA_KEXEC if IMA 2014 2015config ARCH_SUPPORTS_KEXEC_PURGATORY 2016 def_bool y 2017 2018config ARCH_SUPPORTS_KEXEC_SIG 2019 def_bool y 2020 2021config ARCH_SUPPORTS_KEXEC_SIG_FORCE 2022 def_bool y 2023 2024config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG 2025 def_bool y 2026 2027config ARCH_SUPPORTS_KEXEC_JUMP 2028 def_bool y 2029 2030config ARCH_SUPPORTS_CRASH_DUMP 2031 def_bool X86_64 || (X86_32 && HIGHMEM) 2032 2033config ARCH_DEFAULT_CRASH_DUMP 2034 def_bool y 2035 2036config ARCH_SUPPORTS_CRASH_HOTPLUG 2037 def_bool y 2038 2039config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION 2040 def_bool CRASH_RESERVE 2041 2042config PHYSICAL_START 2043 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2044 default "0x1000000" 2045 help 2046 This gives the physical address where the kernel is loaded. 2047 2048 If the kernel is not relocatable (CONFIG_RELOCATABLE=n) then bzImage 2049 will decompress itself to above physical address and run from there. 2050 Otherwise, bzImage will run from the address where it has been loaded 2051 by the boot loader. The only exception is if it is loaded below the 2052 above physical address, in which case it will relocate itself there. 2053 2054 In normal kdump cases one does not have to set/change this option 2055 as now bzImage can be compiled as a completely relocatable image 2056 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2057 address. This option is mainly useful for the folks who don't want 2058 to use a bzImage for capturing the crash dump and want to use a 2059 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2060 to be specifically compiled to run from a specific memory area 2061 (normally a reserved region) and this option comes handy. 2062 2063 So if you are using bzImage for capturing the crash dump, 2064 leave the value here unchanged to 0x1000000 and set 2065 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2066 for capturing the crash dump change this value to start of 2067 the reserved region. In other words, it can be set based on 2068 the "X" value as specified in the "crashkernel=YM@XM" 2069 command line boot parameter passed to the panic-ed 2070 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2071 for more details about crash dumps. 2072 2073 Usage of bzImage for capturing the crash dump is recommended as 2074 one does not have to build two kernels. Same kernel can be used 2075 as production kernel and capture kernel. Above option should have 2076 gone away after relocatable bzImage support is introduced. But it 2077 is present because there are users out there who continue to use 2078 vmlinux for dump capture. This option should go away down the 2079 line. 2080 2081 Don't change this unless you know what you are doing. 2082 2083config RELOCATABLE 2084 bool "Build a relocatable kernel" 2085 default y 2086 help 2087 This builds a kernel image that retains relocation information 2088 so it can be loaded someplace besides the default 1MB. 2089 The relocations tend to make the kernel binary about 10% larger, 2090 but are discarded at runtime. 2091 2092 One use is for the kexec on panic case where the recovery kernel 2093 must live at a different physical address than the primary 2094 kernel. 2095 2096 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2097 it has been loaded at and the compile time physical address 2098 (CONFIG_PHYSICAL_START) is used as the minimum location. 2099 2100config RANDOMIZE_BASE 2101 bool "Randomize the address of the kernel image (KASLR)" 2102 depends on RELOCATABLE 2103 default y 2104 help 2105 In support of Kernel Address Space Layout Randomization (KASLR), 2106 this randomizes the physical address at which the kernel image 2107 is decompressed and the virtual address where the kernel 2108 image is mapped, as a security feature that deters exploit 2109 attempts relying on knowledge of the location of kernel 2110 code internals. 2111 2112 On 64-bit, the kernel physical and virtual addresses are 2113 randomized separately. The physical address will be anywhere 2114 between 16MB and the top of physical memory (up to 64TB). The 2115 virtual address will be randomized from 16MB up to 1GB (9 bits 2116 of entropy). Note that this also reduces the memory space 2117 available to kernel modules from 1.5GB to 1GB. 2118 2119 On 32-bit, the kernel physical and virtual addresses are 2120 randomized together. They will be randomized from 16MB up to 2121 512MB (8 bits of entropy). 2122 2123 Entropy is generated using the RDRAND instruction if it is 2124 supported. If RDTSC is supported, its value is mixed into 2125 the entropy pool as well. If neither RDRAND nor RDTSC are 2126 supported, then entropy is read from the i8254 timer. The 2127 usable entropy is limited by the kernel being built using 2128 2GB addressing, and that PHYSICAL_ALIGN must be at a 2129 minimum of 2MB. As a result, only 10 bits of entropy are 2130 theoretically possible, but the implementations are further 2131 limited due to memory layouts. 2132 2133 If unsure, say Y. 2134 2135# Relocation on x86 needs some additional build support 2136config X86_NEED_RELOCS 2137 def_bool y 2138 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2139 2140config PHYSICAL_ALIGN 2141 hex "Alignment value to which kernel should be aligned" 2142 default "0x200000" 2143 range 0x2000 0x1000000 if X86_32 2144 range 0x200000 0x1000000 if X86_64 2145 help 2146 This value puts the alignment restrictions on physical address 2147 where kernel is loaded and run from. Kernel is compiled for an 2148 address which meets above alignment restriction. 2149 2150 If bootloader loads the kernel at a non-aligned address and 2151 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2152 address aligned to above value and run from there. 2153 2154 If bootloader loads the kernel at a non-aligned address and 2155 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2156 load address and decompress itself to the address it has been 2157 compiled for and run from there. The address for which kernel is 2158 compiled already meets above alignment restrictions. Hence the 2159 end result is that kernel runs from a physical address meeting 2160 above alignment restrictions. 2161 2162 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2163 this value must be a multiple of 0x200000. 2164 2165 Don't change this unless you know what you are doing. 2166 2167config DYNAMIC_MEMORY_LAYOUT 2168 bool 2169 help 2170 This option makes base addresses of vmalloc and vmemmap as well as 2171 __PAGE_OFFSET movable during boot. 2172 2173config RANDOMIZE_MEMORY 2174 bool "Randomize the kernel memory sections" 2175 depends on X86_64 2176 depends on RANDOMIZE_BASE 2177 select DYNAMIC_MEMORY_LAYOUT 2178 default RANDOMIZE_BASE 2179 help 2180 Randomizes the base virtual address of kernel memory sections 2181 (physical memory mapping, vmalloc & vmemmap). This security feature 2182 makes exploits relying on predictable memory locations less reliable. 2183 2184 The order of allocations remains unchanged. Entropy is generated in 2185 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2186 configuration have in average 30,000 different possible virtual 2187 addresses for each memory section. 2188 2189 If unsure, say Y. 2190 2191config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2192 hex "Physical memory mapping padding" if EXPERT 2193 depends on RANDOMIZE_MEMORY 2194 default "0xa" if MEMORY_HOTPLUG 2195 default "0x0" 2196 range 0x1 0x40 if MEMORY_HOTPLUG 2197 range 0x0 0x40 2198 help 2199 Define the padding in terabytes added to the existing physical 2200 memory size during kernel memory randomization. It is useful 2201 for memory hotplug support but reduces the entropy available for 2202 address randomization. 2203 2204 If unsure, leave at the default value. 2205 2206config ADDRESS_MASKING 2207 bool "Linear Address Masking support" 2208 depends on X86_64 2209 depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS 2210 help 2211 Linear Address Masking (LAM) modifies the checking that is applied 2212 to 64-bit linear addresses, allowing software to use of the 2213 untranslated address bits for metadata. 2214 2215 The capability can be used for efficient address sanitizers (ASAN) 2216 implementation and for optimizations in JITs. 2217 2218config HOTPLUG_CPU 2219 def_bool y 2220 depends on SMP 2221 2222config COMPAT_VDSO 2223 def_bool n 2224 prompt "Workaround for glibc 2.3.2 / 2.3.3 (released in year 2003/2004)" 2225 depends on COMPAT_32 2226 help 2227 Certain buggy versions of glibc will crash if they are 2228 presented with a 32-bit vDSO that is not mapped at the address 2229 indicated in its segment table. 2230 2231 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2232 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2233 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2234 the only released version with the bug, but OpenSUSE 9 2235 contains a buggy "glibc 2.3.2". 2236 2237 The symptom of the bug is that everything crashes on startup, saying: 2238 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2239 2240 Saying Y here changes the default value of the vdso32 boot 2241 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2242 This works around the glibc bug but hurts performance. 2243 2244 If unsure, say N: if you are compiling your own kernel, you 2245 are unlikely to be using a buggy version of glibc. 2246 2247choice 2248 prompt "vsyscall table for legacy applications" 2249 depends on X86_64 2250 default LEGACY_VSYSCALL_XONLY 2251 help 2252 Legacy user code that does not know how to find the vDSO expects 2253 to be able to issue three syscalls by calling fixed addresses in 2254 kernel space. Since this location is not randomized with ASLR, 2255 it can be used to assist security vulnerability exploitation. 2256 2257 This setting can be changed at boot time via the kernel command 2258 line parameter vsyscall=[emulate|xonly|none]. Emulate mode 2259 is deprecated and can only be enabled using the kernel command 2260 line. 2261 2262 On a system with recent enough glibc (2.14 or newer) and no 2263 static binaries, you can say None without a performance penalty 2264 to improve security. 2265 2266 If unsure, select "Emulate execution only". 2267 2268 config LEGACY_VSYSCALL_XONLY 2269 bool "Emulate execution only" 2270 help 2271 The kernel traps and emulates calls into the fixed vsyscall 2272 address mapping and does not allow reads. This 2273 configuration is recommended when userspace might use the 2274 legacy vsyscall area but support for legacy binary 2275 instrumentation of legacy code is not needed. It mitigates 2276 certain uses of the vsyscall area as an ASLR-bypassing 2277 buffer. 2278 2279 config LEGACY_VSYSCALL_NONE 2280 bool "None" 2281 help 2282 There will be no vsyscall mapping at all. This will 2283 eliminate any risk of ASLR bypass due to the vsyscall 2284 fixed address mapping. Attempts to use the vsyscalls 2285 will be reported to dmesg, so that either old or 2286 malicious userspace programs can be identified. 2287 2288endchoice 2289 2290config CMDLINE_BOOL 2291 bool "Built-in kernel command line" 2292 help 2293 Allow for specifying boot arguments to the kernel at 2294 build time. On some systems (e.g. embedded ones), it is 2295 necessary or convenient to provide some or all of the 2296 kernel boot arguments with the kernel itself (that is, 2297 to not rely on the boot loader to provide them.) 2298 2299 To compile command line arguments into the kernel, 2300 set this option to 'Y', then fill in the 2301 boot arguments in CONFIG_CMDLINE. 2302 2303 Systems with fully functional boot loaders (i.e. non-embedded) 2304 should leave this option set to 'N'. 2305 2306config CMDLINE 2307 string "Built-in kernel command string" 2308 depends on CMDLINE_BOOL 2309 default "" 2310 help 2311 Enter arguments here that should be compiled into the kernel 2312 image and used at boot time. If the boot loader provides a 2313 command line at boot time, it is appended to this string to 2314 form the full kernel command line, when the system boots. 2315 2316 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2317 change this behavior. 2318 2319 In most cases, the command line (whether built-in or provided 2320 by the boot loader) should specify the device for the root 2321 file system. 2322 2323config CMDLINE_OVERRIDE 2324 bool "Built-in command line overrides boot loader arguments" 2325 depends on CMDLINE_BOOL && CMDLINE != "" 2326 help 2327 Set this option to 'Y' to have the kernel ignore the boot loader 2328 command line, and use ONLY the built-in command line. 2329 2330 This is used to work around broken boot loaders. This should 2331 be set to 'N' under normal conditions. 2332 2333config MODIFY_LDT_SYSCALL 2334 bool "Enable the LDT (local descriptor table)" if EXPERT 2335 default y 2336 help 2337 Linux can allow user programs to install a per-process x86 2338 Local Descriptor Table (LDT) using the modify_ldt(2) system 2339 call. This is required to run 16-bit or segmented code such as 2340 DOSEMU or some Wine programs. It is also used by some very old 2341 threading libraries. 2342 2343 Enabling this feature adds a small amount of overhead to 2344 context switches and increases the low-level kernel attack 2345 surface. Disabling it removes the modify_ldt(2) system call. 2346 2347 Saying 'N' here may make sense for embedded or server kernels. 2348 2349config STRICT_SIGALTSTACK_SIZE 2350 bool "Enforce strict size checking for sigaltstack" 2351 depends on DYNAMIC_SIGFRAME 2352 help 2353 For historical reasons MINSIGSTKSZ is a constant which became 2354 already too small with AVX512 support. Add a mechanism to 2355 enforce strict checking of the sigaltstack size against the 2356 real size of the FPU frame. This option enables the check 2357 by default. It can also be controlled via the kernel command 2358 line option 'strict_sas_size' independent of this config 2359 switch. Enabling it might break existing applications which 2360 allocate a too small sigaltstack but 'work' because they 2361 never get a signal delivered. 2362 2363 Say 'N' unless you want to really enforce this check. 2364 2365config CFI_AUTO_DEFAULT 2366 bool "Attempt to use FineIBT by default at boot time" 2367 depends on FINEIBT 2368 default y 2369 help 2370 Attempt to use FineIBT by default at boot time. If enabled, 2371 this is the same as booting with "cfi=auto". If disabled, 2372 this is the same as booting with "cfi=kcfi". 2373 2374source "kernel/livepatch/Kconfig" 2375 2376config X86_BUS_LOCK_DETECT 2377 bool "Split Lock Detect and Bus Lock Detect support" 2378 depends on CPU_SUP_INTEL || CPU_SUP_AMD 2379 default y 2380 help 2381 Enable Split Lock Detect and Bus Lock Detect functionalities. 2382 See <file:Documentation/arch/x86/buslock.rst> for more information. 2383 2384endmenu 2385 2386config CC_HAS_NAMED_AS 2387 def_bool $(success,echo 'int __seg_fs fs; int __seg_gs gs;' | $(CC) -x c - -S -o /dev/null) 2388 depends on CC_IS_GCC 2389 2390# 2391# -fsanitize=kernel-address (KASAN) and -fsanitize=thread (KCSAN) 2392# are incompatible with named address spaces with GCC < 13.3 2393# (see GCC PR sanitizer/111736 and also PR sanitizer/115172). 2394# 2395 2396config CC_HAS_NAMED_AS_FIXED_SANITIZERS 2397 def_bool y 2398 depends on !(KASAN || KCSAN) || GCC_VERSION >= 130300 2399 depends on !(UBSAN_BOOL && KASAN) || GCC_VERSION >= 140200 2400 2401config USE_X86_SEG_SUPPORT 2402 def_bool CC_HAS_NAMED_AS 2403 depends on CC_HAS_NAMED_AS_FIXED_SANITIZERS 2404 2405config CC_HAS_SLS 2406 def_bool $(cc-option,-mharden-sls=all) 2407 2408config CC_HAS_RETURN_THUNK 2409 def_bool $(cc-option,-mfunction-return=thunk-extern) 2410 2411config CC_HAS_ENTRY_PADDING 2412 def_bool $(cc-option,-fpatchable-function-entry=16,16) 2413 2414config CC_HAS_KCFI_ARITY 2415 def_bool $(cc-option,-fsanitize=kcfi -fsanitize-kcfi-arity) 2416 depends on CC_IS_CLANG && !RUST 2417 2418config FUNCTION_PADDING_CFI 2419 int 2420 default 59 if FUNCTION_ALIGNMENT_64B 2421 default 27 if FUNCTION_ALIGNMENT_32B 2422 default 11 if FUNCTION_ALIGNMENT_16B 2423 default 3 if FUNCTION_ALIGNMENT_8B 2424 default 0 2425 2426# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG 2427# except Kconfig can't do arithmetic :/ 2428config FUNCTION_PADDING_BYTES 2429 int 2430 default FUNCTION_PADDING_CFI if CFI_CLANG 2431 default FUNCTION_ALIGNMENT 2432 2433config CALL_PADDING 2434 def_bool n 2435 depends on CC_HAS_ENTRY_PADDING && OBJTOOL 2436 select FUNCTION_ALIGNMENT_16B 2437 2438config FINEIBT 2439 def_bool y 2440 depends on X86_KERNEL_IBT && CFI_CLANG && MITIGATION_RETPOLINE 2441 select CALL_PADDING 2442 2443config FINEIBT_BHI 2444 def_bool y 2445 depends on FINEIBT && CC_HAS_KCFI_ARITY 2446 2447config HAVE_CALL_THUNKS 2448 def_bool y 2449 depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL 2450 2451config CALL_THUNKS 2452 def_bool n 2453 select CALL_PADDING 2454 2455config PREFIX_SYMBOLS 2456 def_bool y 2457 depends on CALL_PADDING && !CFI_CLANG 2458 2459menuconfig CPU_MITIGATIONS 2460 bool "Mitigations for CPU vulnerabilities" 2461 default y 2462 help 2463 Say Y here to enable options which enable mitigations for hardware 2464 vulnerabilities (usually related to speculative execution). 2465 Mitigations can be disabled or restricted to SMT systems at runtime 2466 via the "mitigations" kernel parameter. 2467 2468 If you say N, all mitigations will be disabled. This CANNOT be 2469 overridden at runtime. 2470 2471 Say 'Y', unless you really know what you are doing. 2472 2473if CPU_MITIGATIONS 2474 2475config MITIGATION_PAGE_TABLE_ISOLATION 2476 bool "Remove the kernel mapping in user mode" 2477 default y 2478 depends on (X86_64 || X86_PAE) 2479 help 2480 This feature reduces the number of hardware side channels by 2481 ensuring that the majority of kernel addresses are not mapped 2482 into userspace. 2483 2484 See Documentation/arch/x86/pti.rst for more details. 2485 2486config MITIGATION_RETPOLINE 2487 bool "Avoid speculative indirect branches in kernel" 2488 select OBJTOOL if HAVE_OBJTOOL 2489 default y 2490 help 2491 Compile kernel with the retpoline compiler options to guard against 2492 kernel-to-user data leaks by avoiding speculative indirect 2493 branches. Requires a compiler with -mindirect-branch=thunk-extern 2494 support for full protection. The kernel may run slower. 2495 2496config MITIGATION_RETHUNK 2497 bool "Enable return-thunks" 2498 depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK 2499 select OBJTOOL if HAVE_OBJTOOL 2500 default y if X86_64 2501 help 2502 Compile the kernel with the return-thunks compiler option to guard 2503 against kernel-to-user data leaks by avoiding return speculation. 2504 Requires a compiler with -mfunction-return=thunk-extern 2505 support for full protection. The kernel may run slower. 2506 2507config MITIGATION_UNRET_ENTRY 2508 bool "Enable UNRET on kernel entry" 2509 depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64 2510 default y 2511 help 2512 Compile the kernel with support for the retbleed=unret mitigation. 2513 2514config MITIGATION_CALL_DEPTH_TRACKING 2515 bool "Mitigate RSB underflow with call depth tracking" 2516 depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS 2517 select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 2518 select CALL_THUNKS 2519 default y 2520 help 2521 Compile the kernel with call depth tracking to mitigate the Intel 2522 SKL Return-Stack-Buffer (RSB) underflow issue. The mitigation is off 2523 by default and needs to be enabled on the kernel command line via the 2524 retbleed=stuff option. For non-affected systems the overhead of this 2525 option is marginal as the call depth tracking is using run-time 2526 generated call thunks in a compiler generated padding area and call 2527 patching. This increases text size by ~5%. For non affected systems 2528 this space is unused. On affected SKL systems this results in a 2529 significant performance gain over the IBRS mitigation. 2530 2531config CALL_THUNKS_DEBUG 2532 bool "Enable call thunks and call depth tracking debugging" 2533 depends on MITIGATION_CALL_DEPTH_TRACKING 2534 select FUNCTION_ALIGNMENT_32B 2535 default n 2536 help 2537 Enable call/ret counters for imbalance detection and build in 2538 a noisy dmesg about callthunks generation and call patching for 2539 trouble shooting. The debug prints need to be enabled on the 2540 kernel command line with 'debug-callthunks'. 2541 Only enable this when you are debugging call thunks as this 2542 creates a noticeable runtime overhead. If unsure say N. 2543 2544config MITIGATION_IBPB_ENTRY 2545 bool "Enable IBPB on kernel entry" 2546 depends on CPU_SUP_AMD && X86_64 2547 default y 2548 help 2549 Compile the kernel with support for the retbleed=ibpb and 2550 spec_rstack_overflow={ibpb,ibpb-vmexit} mitigations. 2551 2552config MITIGATION_IBRS_ENTRY 2553 bool "Enable IBRS on kernel entry" 2554 depends on CPU_SUP_INTEL && X86_64 2555 default y 2556 help 2557 Compile the kernel with support for the spectre_v2=ibrs mitigation. 2558 This mitigates both spectre_v2 and retbleed at great cost to 2559 performance. 2560 2561config MITIGATION_SRSO 2562 bool "Mitigate speculative RAS overflow on AMD" 2563 depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK 2564 default y 2565 help 2566 Enable the SRSO mitigation needed on AMD Zen1-4 machines. 2567 2568config MITIGATION_SLS 2569 bool "Mitigate Straight-Line-Speculation" 2570 depends on CC_HAS_SLS && X86_64 2571 select OBJTOOL if HAVE_OBJTOOL 2572 default n 2573 help 2574 Compile the kernel with straight-line-speculation options to guard 2575 against straight line speculation. The kernel image might be slightly 2576 larger. 2577 2578config MITIGATION_GDS 2579 bool "Mitigate Gather Data Sampling" 2580 depends on CPU_SUP_INTEL 2581 default y 2582 help 2583 Enable mitigation for Gather Data Sampling (GDS). GDS is a hardware 2584 vulnerability which allows unprivileged speculative access to data 2585 which was previously stored in vector registers. The attacker uses gather 2586 instructions to infer the stale vector register data. 2587 2588config MITIGATION_RFDS 2589 bool "RFDS Mitigation" 2590 depends on CPU_SUP_INTEL 2591 default y 2592 help 2593 Enable mitigation for Register File Data Sampling (RFDS) by default. 2594 RFDS is a hardware vulnerability which affects Intel Atom CPUs. It 2595 allows unprivileged speculative access to stale data previously 2596 stored in floating point, vector and integer registers. 2597 See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst> 2598 2599config MITIGATION_SPECTRE_BHI 2600 bool "Mitigate Spectre-BHB (Branch History Injection)" 2601 depends on CPU_SUP_INTEL 2602 default y 2603 help 2604 Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks 2605 where the branch history buffer is poisoned to speculatively steer 2606 indirect branches. 2607 See <file:Documentation/admin-guide/hw-vuln/spectre.rst> 2608 2609config MITIGATION_MDS 2610 bool "Mitigate Microarchitectural Data Sampling (MDS) hardware bug" 2611 depends on CPU_SUP_INTEL 2612 default y 2613 help 2614 Enable mitigation for Microarchitectural Data Sampling (MDS). MDS is 2615 a hardware vulnerability which allows unprivileged speculative access 2616 to data which is available in various CPU internal buffers. 2617 See also <file:Documentation/admin-guide/hw-vuln/mds.rst> 2618 2619config MITIGATION_TAA 2620 bool "Mitigate TSX Asynchronous Abort (TAA) hardware bug" 2621 depends on CPU_SUP_INTEL 2622 default y 2623 help 2624 Enable mitigation for TSX Asynchronous Abort (TAA). TAA is a hardware 2625 vulnerability that allows unprivileged speculative access to data 2626 which is available in various CPU internal buffers by using 2627 asynchronous aborts within an Intel TSX transactional region. 2628 See also <file:Documentation/admin-guide/hw-vuln/tsx_async_abort.rst> 2629 2630config MITIGATION_MMIO_STALE_DATA 2631 bool "Mitigate MMIO Stale Data hardware bug" 2632 depends on CPU_SUP_INTEL 2633 default y 2634 help 2635 Enable mitigation for MMIO Stale Data hardware bugs. Processor MMIO 2636 Stale Data Vulnerabilities are a class of memory-mapped I/O (MMIO) 2637 vulnerabilities that can expose data. The vulnerabilities require the 2638 attacker to have access to MMIO. 2639 See also 2640 <file:Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst> 2641 2642config MITIGATION_L1TF 2643 bool "Mitigate L1 Terminal Fault (L1TF) hardware bug" 2644 depends on CPU_SUP_INTEL 2645 default y 2646 help 2647 Mitigate L1 Terminal Fault (L1TF) hardware bug. L1 Terminal Fault is a 2648 hardware vulnerability which allows unprivileged speculative access to data 2649 available in the Level 1 Data Cache. 2650 See <file:Documentation/admin-guide/hw-vuln/l1tf.rst 2651 2652config MITIGATION_RETBLEED 2653 bool "Mitigate RETBleed hardware bug" 2654 depends on (CPU_SUP_INTEL && MITIGATION_SPECTRE_V2) || MITIGATION_UNRET_ENTRY || MITIGATION_IBPB_ENTRY 2655 default y 2656 help 2657 Enable mitigation for RETBleed (Arbitrary Speculative Code Execution 2658 with Return Instructions) vulnerability. RETBleed is a speculative 2659 execution attack which takes advantage of microarchitectural behavior 2660 in many modern microprocessors, similar to Spectre v2. An 2661 unprivileged attacker can use these flaws to bypass conventional 2662 memory security restrictions to gain read access to privileged memory 2663 that would otherwise be inaccessible. 2664 2665config MITIGATION_SPECTRE_V1 2666 bool "Mitigate SPECTRE V1 hardware bug" 2667 default y 2668 help 2669 Enable mitigation for Spectre V1 (Bounds Check Bypass). Spectre V1 is a 2670 class of side channel attacks that takes advantage of speculative 2671 execution that bypasses conditional branch instructions used for 2672 memory access bounds check. 2673 See also <file:Documentation/admin-guide/hw-vuln/spectre.rst> 2674 2675config MITIGATION_SPECTRE_V2 2676 bool "Mitigate SPECTRE V2 hardware bug" 2677 default y 2678 help 2679 Enable mitigation for Spectre V2 (Branch Target Injection). Spectre 2680 V2 is a class of side channel attacks that takes advantage of 2681 indirect branch predictors inside the processor. In Spectre variant 2 2682 attacks, the attacker can steer speculative indirect branches in the 2683 victim to gadget code by poisoning the branch target buffer of a CPU 2684 used for predicting indirect branch addresses. 2685 See also <file:Documentation/admin-guide/hw-vuln/spectre.rst> 2686 2687config MITIGATION_SRBDS 2688 bool "Mitigate Special Register Buffer Data Sampling (SRBDS) hardware bug" 2689 depends on CPU_SUP_INTEL 2690 default y 2691 help 2692 Enable mitigation for Special Register Buffer Data Sampling (SRBDS). 2693 SRBDS is a hardware vulnerability that allows Microarchitectural Data 2694 Sampling (MDS) techniques to infer values returned from special 2695 register accesses. An unprivileged user can extract values returned 2696 from RDRAND and RDSEED executed on another core or sibling thread 2697 using MDS techniques. 2698 See also 2699 <file:Documentation/admin-guide/hw-vuln/special-register-buffer-data-sampling.rst> 2700 2701config MITIGATION_SSB 2702 bool "Mitigate Speculative Store Bypass (SSB) hardware bug" 2703 default y 2704 help 2705 Enable mitigation for Speculative Store Bypass (SSB). SSB is a 2706 hardware security vulnerability and its exploitation takes advantage 2707 of speculative execution in a similar way to the Meltdown and Spectre 2708 security vulnerabilities. 2709 2710endif 2711 2712config ARCH_HAS_ADD_PAGES 2713 def_bool y 2714 depends on ARCH_ENABLE_MEMORY_HOTPLUG 2715 2716menu "Power management and ACPI options" 2717 2718config ARCH_HIBERNATION_HEADER 2719 def_bool y 2720 depends on HIBERNATION 2721 2722source "kernel/power/Kconfig" 2723 2724source "drivers/acpi/Kconfig" 2725 2726config X86_APM_BOOT 2727 def_bool y 2728 depends on APM 2729 2730menuconfig APM 2731 tristate "APM (Advanced Power Management) BIOS support" 2732 depends on X86_32 && PM_SLEEP 2733 help 2734 APM is a BIOS specification for saving power using several different 2735 techniques. This is mostly useful for battery powered laptops with 2736 APM compliant BIOSes. If you say Y here, the system time will be 2737 reset after a RESUME operation, the /proc/apm device will provide 2738 battery status information, and user-space programs will receive 2739 notification of APM "events" (e.g. battery status change). 2740 2741 If you select "Y" here, you can disable actual use of the APM 2742 BIOS by passing the "apm=off" option to the kernel at boot time. 2743 2744 Note that the APM support is almost completely disabled for 2745 machines with more than one CPU. 2746 2747 In order to use APM, you will need supporting software. For location 2748 and more information, read <file:Documentation/power/apm-acpi.rst> 2749 and the Battery Powered Linux mini-HOWTO, available from 2750 <http://www.tldp.org/docs.html#howto>. 2751 2752 This driver does not spin down disk drives (see the hdparm(8) 2753 manpage ("man 8 hdparm") for that), and it doesn't turn off 2754 VESA-compliant "green" monitors. 2755 2756 This driver does not support the TI 4000M TravelMate and the ACER 2757 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2758 desktop machines also don't have compliant BIOSes, and this driver 2759 may cause those machines to panic during the boot phase. 2760 2761 Generally, if you don't have a battery in your machine, there isn't 2762 much point in using this driver and you should say N. If you get 2763 random kernel OOPSes or reboots that don't seem to be related to 2764 anything, try disabling/enabling this option (or disabling/enabling 2765 APM in your BIOS). 2766 2767 Some other things you should try when experiencing seemingly random, 2768 "weird" problems: 2769 2770 1) make sure that you have enough swap space and that it is 2771 enabled. 2772 2) pass the "idle=poll" option to the kernel 2773 3) switch on floating point emulation in the kernel and pass 2774 the "no387" option to the kernel 2775 4) pass the "floppy=nodma" option to the kernel 2776 5) pass the "mem=4M" option to the kernel (thereby disabling 2777 all but the first 4 MB of RAM) 2778 6) make sure that the CPU is not over clocked. 2779 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2780 8) disable the cache from your BIOS settings 2781 9) install a fan for the video card or exchange video RAM 2782 10) install a better fan for the CPU 2783 11) exchange RAM chips 2784 12) exchange the motherboard. 2785 2786 To compile this driver as a module, choose M here: the 2787 module will be called apm. 2788 2789if APM 2790 2791config APM_IGNORE_USER_SUSPEND 2792 bool "Ignore USER SUSPEND" 2793 help 2794 This option will ignore USER SUSPEND requests. On machines with a 2795 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2796 series notebooks, it is necessary to say Y because of a BIOS bug. 2797 2798config APM_DO_ENABLE 2799 bool "Enable PM at boot time" 2800 help 2801 Enable APM features at boot time. From page 36 of the APM BIOS 2802 specification: "When disabled, the APM BIOS does not automatically 2803 power manage devices, enter the Standby State, enter the Suspend 2804 State, or take power saving steps in response to CPU Idle calls." 2805 This driver will make CPU Idle calls when Linux is idle (unless this 2806 feature is turned off -- see "Do CPU IDLE calls", below). This 2807 should always save battery power, but more complicated APM features 2808 will be dependent on your BIOS implementation. You may need to turn 2809 this option off if your computer hangs at boot time when using APM 2810 support, or if it beeps continuously instead of suspending. Turn 2811 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2812 T400CDT. This is off by default since most machines do fine without 2813 this feature. 2814 2815config APM_CPU_IDLE 2816 depends on CPU_IDLE 2817 bool "Make CPU Idle calls when idle" 2818 help 2819 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2820 On some machines, this can activate improved power savings, such as 2821 a slowed CPU clock rate, when the machine is idle. These idle calls 2822 are made after the idle loop has run for some length of time (e.g., 2823 333 mS). On some machines, this will cause a hang at boot time or 2824 whenever the CPU becomes idle. (On machines with more than one CPU, 2825 this option does nothing.) 2826 2827config APM_DISPLAY_BLANK 2828 bool "Enable console blanking using APM" 2829 help 2830 Enable console blanking using the APM. Some laptops can use this to 2831 turn off the LCD backlight when the screen blanker of the Linux 2832 virtual console blanks the screen. Note that this is only used by 2833 the virtual console screen blanker, and won't turn off the backlight 2834 when using the X Window system. This also doesn't have anything to 2835 do with your VESA-compliant power-saving monitor. Further, this 2836 option doesn't work for all laptops -- it might not turn off your 2837 backlight at all, or it might print a lot of errors to the console, 2838 especially if you are using gpm. 2839 2840config APM_ALLOW_INTS 2841 bool "Allow interrupts during APM BIOS calls" 2842 help 2843 Normally we disable external interrupts while we are making calls to 2844 the APM BIOS as a measure to lessen the effects of a badly behaving 2845 BIOS implementation. The BIOS should reenable interrupts if it 2846 needs to. Unfortunately, some BIOSes do not -- especially those in 2847 many of the newer IBM Thinkpads. If you experience hangs when you 2848 suspend, try setting this to Y. Otherwise, say N. 2849 2850endif # APM 2851 2852source "drivers/cpufreq/Kconfig" 2853 2854source "drivers/cpuidle/Kconfig" 2855 2856source "drivers/idle/Kconfig" 2857 2858endmenu 2859 2860menu "Bus options (PCI etc.)" 2861 2862choice 2863 prompt "PCI access mode" 2864 depends on X86_32 && PCI 2865 default PCI_GOANY 2866 help 2867 On PCI systems, the BIOS can be used to detect the PCI devices and 2868 determine their configuration. However, some old PCI motherboards 2869 have BIOS bugs and may crash if this is done. Also, some embedded 2870 PCI-based systems don't have any BIOS at all. Linux can also try to 2871 detect the PCI hardware directly without using the BIOS. 2872 2873 With this option, you can specify how Linux should detect the 2874 PCI devices. If you choose "BIOS", the BIOS will be used, 2875 if you choose "Direct", the BIOS won't be used, and if you 2876 choose "MMConfig", then PCI Express MMCONFIG will be used. 2877 If you choose "Any", the kernel will try MMCONFIG, then the 2878 direct access method and falls back to the BIOS if that doesn't 2879 work. If unsure, go with the default, which is "Any". 2880 2881config PCI_GOBIOS 2882 bool "BIOS" 2883 2884config PCI_GOMMCONFIG 2885 bool "MMConfig" 2886 2887config PCI_GODIRECT 2888 bool "Direct" 2889 2890config PCI_GOOLPC 2891 bool "OLPC XO-1" 2892 depends on OLPC 2893 2894config PCI_GOANY 2895 bool "Any" 2896 2897endchoice 2898 2899config PCI_BIOS 2900 def_bool y 2901 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2902 2903# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2904config PCI_DIRECT 2905 def_bool y 2906 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2907 2908config PCI_MMCONFIG 2909 bool "Support mmconfig PCI config space access" if X86_64 2910 default y 2911 depends on PCI && (ACPI || JAILHOUSE_GUEST) 2912 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2913 help 2914 Add support for accessing the PCI configuration space as a memory 2915 mapped area. It is the recommended method if the system supports 2916 this (it must have PCI Express and ACPI for it to be available). 2917 2918 In the unlikely case that enabling this configuration option causes 2919 problems, the mechanism can be switched off with the 'pci=nommconf' 2920 command line parameter. 2921 2922 Say N only if you are sure that your platform does not support this 2923 access method or you have problems caused by it. 2924 2925 Say Y otherwise. 2926 2927config PCI_OLPC 2928 def_bool y 2929 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2930 2931config PCI_XEN 2932 def_bool y 2933 depends on PCI && XEN 2934 2935config MMCONF_FAM10H 2936 def_bool y 2937 depends on X86_64 && PCI_MMCONFIG && ACPI 2938 2939config PCI_CNB20LE_QUIRK 2940 bool "Read PCI host bridge windows from the CNB20LE chipset" if EXPERT 2941 depends on X86_32 && PCI 2942 help 2943 Read the PCI windows out of the CNB20LE host bridge. This allows 2944 PCI hotplug to work on systems with the CNB20LE chipset which do 2945 not have ACPI. 2946 2947 The ServerWorks (later Broadcom) CNB20LE was a chipset designed 2948 most probably only for Pentium III. 2949 2950 To find out if you have such a chipset, search for a PCI device with 2951 1166:0009 PCI IDs, for example by executing 2952 lspci -nn | grep '1166:0009' 2953 The code is inactive if there is none. 2954 2955 There's no public spec for this chipset, and this functionality 2956 is known to be incomplete. 2957 2958 You should say N unless you know you need this. 2959 2960config ISA_BUS 2961 bool "ISA bus support on modern systems" if EXPERT 2962 help 2963 Expose ISA bus device drivers and options available for selection and 2964 configuration. Enable this option if your target machine has an ISA 2965 bus. ISA is an older system, displaced by PCI and newer bus 2966 architectures -- if your target machine is modern, it probably does 2967 not have an ISA bus. 2968 2969 If unsure, say N. 2970 2971# x86_64 have no ISA slots, but can have ISA-style DMA. 2972config ISA_DMA_API 2973 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2974 default y 2975 help 2976 Enables ISA-style DMA support for devices requiring such controllers. 2977 If unsure, say Y. 2978 2979if X86_32 2980 2981config ISA 2982 bool "ISA support" 2983 help 2984 Find out whether you have ISA slots on your motherboard. ISA is the 2985 name of a bus system, i.e. the way the CPU talks to the other stuff 2986 inside your box. Other bus systems are PCI, EISA, MicroChannel 2987 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2988 newer boards don't support it. If you have ISA, say Y, otherwise N. 2989 2990config SCx200 2991 tristate "NatSemi SCx200 support" 2992 help 2993 This provides basic support for National Semiconductor's 2994 (now AMD's) Geode processors. The driver probes for the 2995 PCI-IDs of several on-chip devices, so its a good dependency 2996 for other scx200_* drivers. 2997 2998 If compiled as a module, the driver is named scx200. 2999 3000config SCx200HR_TIMER 3001 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 3002 depends on SCx200 3003 default y 3004 help 3005 This driver provides a clocksource built upon the on-chip 3006 27MHz high-resolution timer. Its also a workaround for 3007 NSC Geode SC-1100's buggy TSC, which loses time when the 3008 processor goes idle (as is done by the scheduler). The 3009 other workaround is idle=poll boot option. 3010 3011config OLPC 3012 bool "One Laptop Per Child support" 3013 depends on !X86_PAE 3014 select GPIOLIB 3015 select OF 3016 select OF_PROMTREE 3017 select IRQ_DOMAIN 3018 select OLPC_EC 3019 help 3020 Add support for detecting the unique features of the OLPC 3021 XO hardware. 3022 3023config OLPC_XO1_PM 3024 bool "OLPC XO-1 Power Management" 3025 depends on OLPC && MFD_CS5535=y && PM_SLEEP 3026 help 3027 Add support for poweroff and suspend of the OLPC XO-1 laptop. 3028 3029config OLPC_XO1_RTC 3030 bool "OLPC XO-1 Real Time Clock" 3031 depends on OLPC_XO1_PM && RTC_DRV_CMOS 3032 help 3033 Add support for the XO-1 real time clock, which can be used as a 3034 programmable wakeup source. 3035 3036config OLPC_XO1_SCI 3037 bool "OLPC XO-1 SCI extras" 3038 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 3039 depends on INPUT=y 3040 select POWER_SUPPLY 3041 help 3042 Add support for SCI-based features of the OLPC XO-1 laptop: 3043 - EC-driven system wakeups 3044 - Power button 3045 - Ebook switch 3046 - Lid switch 3047 - AC adapter status updates 3048 - Battery status updates 3049 3050config OLPC_XO15_SCI 3051 bool "OLPC XO-1.5 SCI extras" 3052 depends on OLPC && ACPI 3053 select POWER_SUPPLY 3054 help 3055 Add support for SCI-based features of the OLPC XO-1.5 laptop: 3056 - EC-driven system wakeups 3057 - AC adapter status updates 3058 - Battery status updates 3059 3060config GEODE_COMMON 3061 bool 3062 3063config ALIX 3064 bool "PCEngines ALIX System Support (LED setup)" 3065 select GPIOLIB 3066 select GEODE_COMMON 3067 help 3068 This option enables system support for the PCEngines ALIX. 3069 At present this just sets up LEDs for GPIO control on 3070 ALIX2/3/6 boards. However, other system specific setup should 3071 get added here. 3072 3073 Note: You must still enable the drivers for GPIO and LED support 3074 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 3075 3076 Note: You have to set alix.force=1 for boards with Award BIOS. 3077 3078config NET5501 3079 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 3080 select GPIOLIB 3081 select GEODE_COMMON 3082 help 3083 This option enables system support for the Soekris Engineering net5501. 3084 3085config GEOS 3086 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 3087 select GPIOLIB 3088 select GEODE_COMMON 3089 depends on DMI 3090 help 3091 This option enables system support for the Traverse Technologies GEOS. 3092 3093config TS5500 3094 bool "Technologic Systems TS-5500 platform support" 3095 depends on MELAN 3096 select CHECK_SIGNATURE 3097 select NEW_LEDS 3098 select LEDS_CLASS 3099 help 3100 This option enables system support for the Technologic Systems TS-5500. 3101 3102endif # X86_32 3103 3104config AMD_NB 3105 def_bool y 3106 depends on AMD_NODE 3107 3108config AMD_NODE 3109 def_bool y 3110 depends on CPU_SUP_AMD && PCI 3111 3112endmenu 3113 3114menu "Binary Emulations" 3115 3116config IA32_EMULATION 3117 bool "IA32 Emulation" 3118 depends on X86_64 3119 select ARCH_WANT_OLD_COMPAT_IPC 3120 select BINFMT_ELF 3121 select COMPAT_OLD_SIGACTION 3122 help 3123 Include code to run legacy 32-bit programs under a 3124 64-bit kernel. You should likely turn this on, unless you're 3125 100% sure that you don't have any 32-bit programs left. 3126 3127config IA32_EMULATION_DEFAULT_DISABLED 3128 bool "IA32 emulation disabled by default" 3129 default n 3130 depends on IA32_EMULATION 3131 help 3132 Make IA32 emulation disabled by default. This prevents loading 32-bit 3133 processes and access to 32-bit syscalls. If unsure, leave it to its 3134 default value. 3135 3136config X86_X32_ABI 3137 bool "x32 ABI for 64-bit mode" 3138 depends on X86_64 3139 # llvm-objcopy does not convert x86_64 .note.gnu.property or 3140 # compressed debug sections to x86_x32 properly: 3141 # https://github.com/ClangBuiltLinux/linux/issues/514 3142 # https://github.com/ClangBuiltLinux/linux/issues/1141 3143 depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm) 3144 help 3145 Include code to run binaries for the x32 native 32-bit ABI 3146 for 64-bit processors. An x32 process gets access to the 3147 full 64-bit register file and wide data path while leaving 3148 pointers at 32 bits for smaller memory footprint. 3149 3150config COMPAT_32 3151 def_bool y 3152 depends on IA32_EMULATION || X86_32 3153 select HAVE_UID16 3154 select OLD_SIGSUSPEND3 3155 3156config COMPAT 3157 def_bool y 3158 depends on IA32_EMULATION || X86_X32_ABI 3159 3160config COMPAT_FOR_U64_ALIGNMENT 3161 def_bool y 3162 depends on COMPAT 3163 3164endmenu 3165 3166config HAVE_ATOMIC_IOMAP 3167 def_bool y 3168 depends on X86_32 3169 3170source "arch/x86/kvm/Kconfig" 3171 3172source "arch/x86/Kconfig.cpufeatures" 3173 3174source "arch/x86/Kconfig.assembler" 3175