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_SUPPORTS_INT128 if CC_HAS_INT128 30 select ARCH_SUPPORTS_PER_VMA_LOCK 31 select HAVE_ARCH_SOFT_DIRTY 32 select MODULES_USE_ELF_RELA 33 select NEED_DMA_MAP_STATE 34 select SWIOTLB 35 select ARCH_HAS_ELFCORE_COMPAT 36 select ZONE_DMA32 37 38config FORCE_DYNAMIC_FTRACE 39 def_bool y 40 depends on X86_32 41 depends on FUNCTION_TRACER 42 select DYNAMIC_FTRACE 43 help 44 We keep the static function tracing (!DYNAMIC_FTRACE) around 45 in order to test the non static function tracing in the 46 generic code, as other architectures still use it. But we 47 only need to keep it around for x86_64. No need to keep it 48 for x86_32. For x86_32, force DYNAMIC_FTRACE. 49# 50# Arch settings 51# 52# ( Note that options that are marked 'if X86_64' could in principle be 53# ported to 32-bit as well. ) 54# 55config X86 56 def_bool y 57 # 58 # Note: keep this list sorted alphabetically 59 # 60 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 61 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 62 select ACPI_HOTPLUG_CPU if ACPI_PROCESSOR && HOTPLUG_CPU 63 select ARCH_32BIT_OFF_T if X86_32 64 select ARCH_CLOCKSOURCE_INIT 65 select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 66 select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION 67 select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64 68 select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG 69 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE) 70 select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE 71 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 72 select ARCH_HAS_CACHE_LINE_SIZE 73 select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION 74 select ARCH_HAS_CPU_FINALIZE_INIT 75 select ARCH_HAS_CPU_PASID if IOMMU_SVA 76 select ARCH_HAS_CURRENT_STACK_POINTER 77 select ARCH_HAS_DEBUG_VIRTUAL 78 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 79 select ARCH_HAS_DEVMEM_IS_ALLOWED 80 select ARCH_HAS_EARLY_DEBUG if KGDB 81 select ARCH_HAS_ELF_RANDOMIZE 82 select ARCH_HAS_FAST_MULTIPLIER 83 select ARCH_HAS_FORTIFY_SOURCE 84 select ARCH_HAS_GCOV_PROFILE_ALL 85 select ARCH_HAS_KCOV if X86_64 86 select ARCH_HAS_MEM_ENCRYPT 87 select ARCH_HAS_MEMBARRIER_SYNC_CORE 88 select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS 89 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 90 select ARCH_HAS_PMEM_API if X86_64 91 select ARCH_HAS_PTE_DEVMAP if X86_64 92 select ARCH_HAS_PTE_SPECIAL 93 select ARCH_HAS_HW_PTE_YOUNG 94 select ARCH_HAS_NONLEAF_PMD_YOUNG if PGTABLE_LEVELS > 2 95 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 96 select ARCH_HAS_COPY_MC if X86_64 97 select ARCH_HAS_SET_MEMORY 98 select ARCH_HAS_SET_DIRECT_MAP 99 select ARCH_HAS_STRICT_KERNEL_RWX 100 select ARCH_HAS_STRICT_MODULE_RWX 101 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 102 select ARCH_HAS_SYSCALL_WRAPPER 103 select ARCH_HAS_UBSAN 104 select ARCH_HAS_DEBUG_WX 105 select ARCH_HAS_ZONE_DMA_SET if EXPERT 106 select ARCH_HAVE_NMI_SAFE_CMPXCHG 107 select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 108 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 109 select ARCH_MIGHT_HAVE_PC_PARPORT 110 select ARCH_MIGHT_HAVE_PC_SERIO 111 select ARCH_STACKWALK 112 select ARCH_SUPPORTS_ACPI 113 select ARCH_SUPPORTS_ATOMIC_RMW 114 select ARCH_SUPPORTS_DEBUG_PAGEALLOC 115 select ARCH_SUPPORTS_PAGE_TABLE_CHECK if X86_64 116 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 117 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 118 select ARCH_SUPPORTS_CFI_CLANG if X86_64 119 select ARCH_USES_CFI_TRAPS if X86_64 && CFI_CLANG 120 select ARCH_SUPPORTS_LTO_CLANG 121 select ARCH_SUPPORTS_LTO_CLANG_THIN 122 select ARCH_USE_BUILTIN_BSWAP 123 select ARCH_USE_CMPXCHG_LOCKREF if X86_CMPXCHG64 124 select ARCH_USE_MEMTEST 125 select ARCH_USE_QUEUED_RWLOCKS 126 select ARCH_USE_QUEUED_SPINLOCKS 127 select ARCH_USE_SYM_ANNOTATIONS 128 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 129 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 130 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 131 select ARCH_WANTS_NO_INSTR 132 select ARCH_WANT_GENERAL_HUGETLB 133 select ARCH_WANT_HUGE_PMD_SHARE 134 select ARCH_WANT_LD_ORPHAN_WARN 135 select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP if X86_64 136 select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP if X86_64 137 select ARCH_WANTS_THP_SWAP if X86_64 138 select ARCH_HAS_PARANOID_L1D_FLUSH 139 select BUILDTIME_TABLE_SORT 140 select CLKEVT_I8253 141 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 142 select CLOCKSOURCE_WATCHDOG 143 # Word-size accesses may read uninitialized data past the trailing \0 144 # in strings and cause false KMSAN reports. 145 select DCACHE_WORD_ACCESS if !KMSAN 146 select DYNAMIC_SIGFRAME 147 select EDAC_ATOMIC_SCRUB 148 select EDAC_SUPPORT 149 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 150 select GENERIC_CLOCKEVENTS_BROADCAST_IDLE if GENERIC_CLOCKEVENTS_BROADCAST 151 select GENERIC_CLOCKEVENTS_MIN_ADJUST 152 select GENERIC_CMOS_UPDATE 153 select GENERIC_CPU_AUTOPROBE 154 select GENERIC_CPU_DEVICES 155 select GENERIC_CPU_VULNERABILITIES 156 select GENERIC_EARLY_IOREMAP 157 select GENERIC_ENTRY 158 select GENERIC_IOMAP 159 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 160 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 161 select GENERIC_IRQ_MIGRATION if SMP 162 select GENERIC_IRQ_PROBE 163 select GENERIC_IRQ_RESERVATION_MODE 164 select GENERIC_IRQ_SHOW 165 select GENERIC_PENDING_IRQ if SMP 166 select GENERIC_PTDUMP 167 select GENERIC_SMP_IDLE_THREAD 168 select GENERIC_TIME_VSYSCALL 169 select GENERIC_GETTIMEOFDAY 170 select GENERIC_VDSO_TIME_NS 171 select GUP_GET_PXX_LOW_HIGH if X86_PAE 172 select HARDIRQS_SW_RESEND 173 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 174 select HAS_IOPORT 175 select HAVE_ACPI_APEI if ACPI 176 select HAVE_ACPI_APEI_NMI if ACPI 177 select HAVE_ALIGNED_STRUCT_PAGE 178 select HAVE_ARCH_AUDITSYSCALL 179 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 180 select HAVE_ARCH_HUGE_VMALLOC if X86_64 181 select HAVE_ARCH_JUMP_LABEL 182 select HAVE_ARCH_JUMP_LABEL_RELATIVE 183 select HAVE_ARCH_KASAN if X86_64 184 select HAVE_ARCH_KASAN_VMALLOC if X86_64 185 select HAVE_ARCH_KFENCE 186 select HAVE_ARCH_KMSAN if X86_64 187 select HAVE_ARCH_KGDB 188 select HAVE_ARCH_MMAP_RND_BITS if MMU 189 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 190 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 191 select HAVE_ARCH_PREL32_RELOCATIONS 192 select HAVE_ARCH_SECCOMP_FILTER 193 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 194 select HAVE_ARCH_STACKLEAK 195 select HAVE_ARCH_TRACEHOOK 196 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 197 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 198 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 199 select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 200 select HAVE_ARCH_VMAP_STACK if X86_64 201 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 202 select HAVE_ARCH_WITHIN_STACK_FRAMES 203 select HAVE_ASM_MODVERSIONS 204 select HAVE_CMPXCHG_DOUBLE 205 select HAVE_CMPXCHG_LOCAL 206 select HAVE_CONTEXT_TRACKING_USER if X86_64 207 select HAVE_CONTEXT_TRACKING_USER_OFFSTACK if HAVE_CONTEXT_TRACKING_USER 208 select HAVE_C_RECORDMCOUNT 209 select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL 210 select HAVE_OBJTOOL_NOP_MCOUNT if HAVE_OBJTOOL_MCOUNT 211 select HAVE_BUILDTIME_MCOUNT_SORT 212 select HAVE_DEBUG_KMEMLEAK 213 select HAVE_DMA_CONTIGUOUS 214 select HAVE_DYNAMIC_FTRACE 215 select HAVE_DYNAMIC_FTRACE_WITH_REGS 216 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 217 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 218 select HAVE_SAMPLE_FTRACE_DIRECT if X86_64 219 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64 220 select HAVE_EBPF_JIT 221 select HAVE_EFFICIENT_UNALIGNED_ACCESS 222 select HAVE_EISA 223 select HAVE_EXIT_THREAD 224 select HAVE_FAST_GUP 225 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 226 select HAVE_FTRACE_MCOUNT_RECORD 227 select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER 228 select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) 229 select HAVE_FUNCTION_TRACER 230 select HAVE_GCC_PLUGINS 231 select HAVE_HW_BREAKPOINT 232 select HAVE_IOREMAP_PROT 233 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 234 select HAVE_IRQ_TIME_ACCOUNTING 235 select HAVE_JUMP_LABEL_HACK if HAVE_OBJTOOL 236 select HAVE_KERNEL_BZIP2 237 select HAVE_KERNEL_GZIP 238 select HAVE_KERNEL_LZ4 239 select HAVE_KERNEL_LZMA 240 select HAVE_KERNEL_LZO 241 select HAVE_KERNEL_XZ 242 select HAVE_KERNEL_ZSTD 243 select HAVE_KPROBES 244 select HAVE_KPROBES_ON_FTRACE 245 select HAVE_FUNCTION_ERROR_INJECTION 246 select HAVE_KRETPROBES 247 select HAVE_RETHOOK 248 select HAVE_LIVEPATCH if X86_64 249 select HAVE_MIXED_BREAKPOINTS_REGS 250 select HAVE_MOD_ARCH_SPECIFIC 251 select HAVE_MOVE_PMD 252 select HAVE_MOVE_PUD 253 select HAVE_NOINSTR_HACK if HAVE_OBJTOOL 254 select HAVE_NMI 255 select HAVE_NOINSTR_VALIDATION if HAVE_OBJTOOL 256 select HAVE_OBJTOOL if X86_64 257 select HAVE_OPTPROBES 258 select HAVE_PAGE_SIZE_4KB 259 select HAVE_PCSPKR_PLATFORM 260 select HAVE_PERF_EVENTS 261 select HAVE_PERF_EVENTS_NMI 262 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 263 select HAVE_PCI 264 select HAVE_PERF_REGS 265 select HAVE_PERF_USER_STACK_DUMP 266 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 267 select MMU_GATHER_MERGE_VMAS 268 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 269 select HAVE_REGS_AND_STACK_ACCESS_API 270 select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC || STACK_VALIDATION 271 select HAVE_FUNCTION_ARG_ACCESS_API 272 select HAVE_SETUP_PER_CPU_AREA 273 select HAVE_SOFTIRQ_ON_OWN_STACK 274 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 275 select HAVE_STACK_VALIDATION if HAVE_OBJTOOL 276 select HAVE_STATIC_CALL 277 select HAVE_STATIC_CALL_INLINE if HAVE_OBJTOOL 278 select HAVE_PREEMPT_DYNAMIC_CALL 279 select HAVE_RSEQ 280 select HAVE_RUST if X86_64 281 select HAVE_SYSCALL_TRACEPOINTS 282 select HAVE_UACCESS_VALIDATION if HAVE_OBJTOOL 283 select HAVE_UNSTABLE_SCHED_CLOCK 284 select HAVE_USER_RETURN_NOTIFIER 285 select HAVE_GENERIC_VDSO 286 select HOTPLUG_PARALLEL if SMP && X86_64 287 select HOTPLUG_SMT if SMP 288 select HOTPLUG_SPLIT_STARTUP if SMP && X86_32 289 select IRQ_FORCED_THREADING 290 select LOCK_MM_AND_FIND_VMA 291 select NEED_PER_CPU_EMBED_FIRST_CHUNK 292 select NEED_PER_CPU_PAGE_FIRST_CHUNK 293 select NEED_SG_DMA_LENGTH 294 select PCI_DOMAINS if PCI 295 select PCI_LOCKLESS_CONFIG if PCI 296 select PERF_EVENTS 297 select RTC_LIB 298 select RTC_MC146818_LIB 299 select SPARSE_IRQ 300 select SYSCTL_EXCEPTION_TRACE 301 select THREAD_INFO_IN_TASK 302 select TRACE_IRQFLAGS_SUPPORT 303 select TRACE_IRQFLAGS_NMI_SUPPORT 304 select USER_STACKTRACE_SUPPORT 305 select HAVE_ARCH_KCSAN if X86_64 306 select PROC_PID_ARCH_STATUS if PROC_FS 307 select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX 308 select FUNCTION_ALIGNMENT_16B if X86_64 || X86_ALIGNMENT_16 309 select FUNCTION_ALIGNMENT_4B 310 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 311 select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 312 313config INSTRUCTION_DECODER 314 def_bool y 315 depends on KPROBES || PERF_EVENTS || UPROBES 316 317config OUTPUT_FORMAT 318 string 319 default "elf32-i386" if X86_32 320 default "elf64-x86-64" if X86_64 321 322config LOCKDEP_SUPPORT 323 def_bool y 324 325config STACKTRACE_SUPPORT 326 def_bool y 327 328config MMU 329 def_bool y 330 331config ARCH_MMAP_RND_BITS_MIN 332 default 28 if 64BIT 333 default 8 334 335config ARCH_MMAP_RND_BITS_MAX 336 default 32 if 64BIT 337 default 16 338 339config ARCH_MMAP_RND_COMPAT_BITS_MIN 340 default 8 341 342config ARCH_MMAP_RND_COMPAT_BITS_MAX 343 default 16 344 345config SBUS 346 bool 347 348config GENERIC_ISA_DMA 349 def_bool y 350 depends on ISA_DMA_API 351 352config GENERIC_CSUM 353 bool 354 default y if KMSAN || KASAN 355 356config GENERIC_BUG 357 def_bool y 358 depends on BUG 359 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 360 361config GENERIC_BUG_RELATIVE_POINTERS 362 bool 363 364config ARCH_MAY_HAVE_PC_FDC 365 def_bool y 366 depends on ISA_DMA_API 367 368config GENERIC_CALIBRATE_DELAY 369 def_bool y 370 371config ARCH_HAS_CPU_RELAX 372 def_bool y 373 374config ARCH_HIBERNATION_POSSIBLE 375 def_bool y 376 377config ARCH_SUSPEND_POSSIBLE 378 def_bool y 379 380config AUDIT_ARCH 381 def_bool y if X86_64 382 383config KASAN_SHADOW_OFFSET 384 hex 385 depends on KASAN 386 default 0xdffffc0000000000 387 388config HAVE_INTEL_TXT 389 def_bool y 390 depends on INTEL_IOMMU && ACPI 391 392config X86_64_SMP 393 def_bool y 394 depends on X86_64 && SMP 395 396config ARCH_SUPPORTS_UPROBES 397 def_bool y 398 399config FIX_EARLYCON_MEM 400 def_bool y 401 402config DYNAMIC_PHYSICAL_MASK 403 bool 404 405config PGTABLE_LEVELS 406 int 407 default 5 if X86_5LEVEL 408 default 4 if X86_64 409 default 3 if X86_PAE 410 default 2 411 412config CC_HAS_SANE_STACKPROTECTOR 413 bool 414 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT 415 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) 416 help 417 We have to make sure stack protector is unconditionally disabled if 418 the compiler produces broken code or if it does not let us control 419 the segment on 32-bit kernels. 420 421menu "Processor type and features" 422 423config SMP 424 bool "Symmetric multi-processing support" 425 help 426 This enables support for systems with more than one CPU. If you have 427 a system with only one CPU, say N. If you have a system with more 428 than one CPU, say Y. 429 430 If you say N here, the kernel will run on uni- and multiprocessor 431 machines, but will use only one CPU of a multiprocessor machine. If 432 you say Y here, the kernel will run on many, but not all, 433 uniprocessor machines. On a uniprocessor machine, the kernel 434 will run faster if you say N here. 435 436 Note that if you say Y here and choose architecture "586" or 437 "Pentium" under "Processor family", the kernel will not work on 486 438 architectures. Similarly, multiprocessor kernels for the "PPro" 439 architecture may not work on all Pentium based boards. 440 441 People using multiprocessor machines who say Y here should also say 442 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 443 Management" code will be disabled if you say Y here. 444 445 See also <file:Documentation/arch/x86/i386/IO-APIC.rst>, 446 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 447 <http://www.tldp.org/docs.html#howto>. 448 449 If you don't know what to do here, say N. 450 451config X86_X2APIC 452 bool "Support x2apic" 453 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 454 help 455 This enables x2apic support on CPUs that have this feature. 456 457 This allows 32-bit apic IDs (so it can support very large systems), 458 and accesses the local apic via MSRs not via mmio. 459 460 Some Intel systems circa 2022 and later are locked into x2APIC mode 461 and can not fall back to the legacy APIC modes if SGX or TDX are 462 enabled in the BIOS. They will boot with very reduced functionality 463 without enabling this option. 464 465 If you don't know what to do here, say N. 466 467config X86_MPPARSE 468 bool "Enable MPS table" if ACPI 469 default y 470 depends on X86_LOCAL_APIC 471 help 472 For old smp systems that do not have proper acpi support. Newer systems 473 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 474 475config X86_CPU_RESCTRL 476 bool "x86 CPU resource control support" 477 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 478 select KERNFS 479 select PROC_CPU_RESCTRL if PROC_FS 480 help 481 Enable x86 CPU resource control support. 482 483 Provide support for the allocation and monitoring of system resources 484 usage by the CPU. 485 486 Intel calls this Intel Resource Director Technology 487 (Intel(R) RDT). More information about RDT can be found in the 488 Intel x86 Architecture Software Developer Manual. 489 490 AMD calls this AMD Platform Quality of Service (AMD QoS). 491 More information about AMD QoS can be found in the AMD64 Technology 492 Platform Quality of Service Extensions manual. 493 494 Say N if unsure. 495 496config X86_FRED 497 bool "Flexible Return and Event Delivery" 498 depends on X86_64 499 help 500 When enabled, try to use Flexible Return and Event Delivery 501 instead of the legacy SYSCALL/SYSENTER/IDT architecture for 502 ring transitions and exception/interrupt handling if the 503 system supports. 504 505if X86_32 506config X86_BIGSMP 507 bool "Support for big SMP systems with more than 8 CPUs" 508 depends on SMP 509 help 510 This option is needed for the systems that have more than 8 CPUs. 511 512config X86_EXTENDED_PLATFORM 513 bool "Support for extended (non-PC) x86 platforms" 514 default y 515 help 516 If you disable this option then the kernel will only support 517 standard PC platforms. (which covers the vast majority of 518 systems out there.) 519 520 If you enable this option then you'll be able to select support 521 for the following (non-PC) 32 bit x86 platforms: 522 Goldfish (Android emulator) 523 AMD Elan 524 RDC R-321x SoC 525 SGI 320/540 (Visual Workstation) 526 STA2X11-based (e.g. Northville) 527 Moorestown MID devices 528 529 If you have one of these systems, or if you want to build a 530 generic distribution kernel, say Y here - otherwise say N. 531endif # X86_32 532 533if X86_64 534config X86_EXTENDED_PLATFORM 535 bool "Support for extended (non-PC) x86 platforms" 536 default y 537 help 538 If you disable this option then the kernel will only support 539 standard PC platforms. (which covers the vast majority of 540 systems out there.) 541 542 If you enable this option then you'll be able to select support 543 for the following (non-PC) 64 bit x86 platforms: 544 Numascale NumaChip 545 ScaleMP vSMP 546 SGI Ultraviolet 547 548 If you have one of these systems, or if you want to build a 549 generic distribution kernel, say Y here - otherwise say N. 550endif # X86_64 551# This is an alphabetically sorted list of 64 bit extended platforms 552# Please maintain the alphabetic order if and when there are additions 553config X86_NUMACHIP 554 bool "Numascale NumaChip" 555 depends on X86_64 556 depends on X86_EXTENDED_PLATFORM 557 depends on NUMA 558 depends on SMP 559 depends on X86_X2APIC 560 depends on PCI_MMCONFIG 561 help 562 Adds support for Numascale NumaChip large-SMP systems. Needed to 563 enable more than ~168 cores. 564 If you don't have one of these, you should say N here. 565 566config X86_VSMP 567 bool "ScaleMP vSMP" 568 select HYPERVISOR_GUEST 569 select PARAVIRT 570 depends on X86_64 && PCI 571 depends on X86_EXTENDED_PLATFORM 572 depends on SMP 573 help 574 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 575 supposed to run on these EM64T-based machines. Only choose this option 576 if you have one of these machines. 577 578config X86_UV 579 bool "SGI Ultraviolet" 580 depends on X86_64 581 depends on X86_EXTENDED_PLATFORM 582 depends on NUMA 583 depends on EFI 584 depends on KEXEC_CORE 585 depends on X86_X2APIC 586 depends on PCI 587 help 588 This option is needed in order to support SGI Ultraviolet systems. 589 If you don't have one of these, you should say N here. 590 591# Following is an alphabetically sorted list of 32 bit extended platforms 592# Please maintain the alphabetic order if and when there are additions 593 594config X86_GOLDFISH 595 bool "Goldfish (Virtual Platform)" 596 depends on X86_EXTENDED_PLATFORM 597 help 598 Enable support for the Goldfish virtual platform used primarily 599 for Android development. Unless you are building for the Android 600 Goldfish emulator say N here. 601 602config X86_INTEL_CE 603 bool "CE4100 TV platform" 604 depends on PCI 605 depends on PCI_GODIRECT 606 depends on X86_IO_APIC 607 depends on X86_32 608 depends on X86_EXTENDED_PLATFORM 609 select X86_REBOOTFIXUPS 610 select OF 611 select OF_EARLY_FLATTREE 612 help 613 Select for the Intel CE media processor (CE4100) SOC. 614 This option compiles in support for the CE4100 SOC for settop 615 boxes and media devices. 616 617config X86_INTEL_MID 618 bool "Intel MID platform support" 619 depends on X86_EXTENDED_PLATFORM 620 depends on X86_PLATFORM_DEVICES 621 depends on PCI 622 depends on X86_64 || (PCI_GOANY && X86_32) 623 depends on X86_IO_APIC 624 select I2C 625 select DW_APB_TIMER 626 select INTEL_SCU_PCI 627 help 628 Select to build a kernel capable of supporting Intel MID (Mobile 629 Internet Device) platform systems which do not have the PCI legacy 630 interfaces. If you are building for a PC class system say N here. 631 632 Intel MID platforms are based on an Intel processor and chipset which 633 consume less power than most of the x86 derivatives. 634 635config X86_INTEL_QUARK 636 bool "Intel Quark platform support" 637 depends on X86_32 638 depends on X86_EXTENDED_PLATFORM 639 depends on X86_PLATFORM_DEVICES 640 depends on X86_TSC 641 depends on PCI 642 depends on PCI_GOANY 643 depends on X86_IO_APIC 644 select IOSF_MBI 645 select INTEL_IMR 646 select COMMON_CLK 647 help 648 Select to include support for Quark X1000 SoC. 649 Say Y here if you have a Quark based system such as the Arduino 650 compatible Intel Galileo. 651 652config X86_INTEL_LPSS 653 bool "Intel Low Power Subsystem Support" 654 depends on X86 && ACPI && PCI 655 select COMMON_CLK 656 select PINCTRL 657 select IOSF_MBI 658 help 659 Select to build support for Intel Low Power Subsystem such as 660 found on Intel Lynxpoint PCH. Selecting this option enables 661 things like clock tree (common clock framework) and pincontrol 662 which are needed by the LPSS peripheral drivers. 663 664config X86_AMD_PLATFORM_DEVICE 665 bool "AMD ACPI2Platform devices support" 666 depends on ACPI 667 select COMMON_CLK 668 select PINCTRL 669 help 670 Select to interpret AMD specific ACPI device to platform device 671 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 672 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 673 implemented under PINCTRL subsystem. 674 675config IOSF_MBI 676 tristate "Intel SoC IOSF Sideband support for SoC platforms" 677 depends on PCI 678 help 679 This option enables sideband register access support for Intel SoC 680 platforms. On these platforms the IOSF sideband is used in lieu of 681 MSR's for some register accesses, mostly but not limited to thermal 682 and power. Drivers may query the availability of this device to 683 determine if they need the sideband in order to work on these 684 platforms. The sideband is available on the following SoC products. 685 This list is not meant to be exclusive. 686 - BayTrail 687 - Braswell 688 - Quark 689 690 You should say Y if you are running a kernel on one of these SoC's. 691 692config IOSF_MBI_DEBUG 693 bool "Enable IOSF sideband access through debugfs" 694 depends on IOSF_MBI && DEBUG_FS 695 help 696 Select this option to expose the IOSF sideband access registers (MCR, 697 MDR, MCRX) through debugfs to write and read register information from 698 different units on the SoC. This is most useful for obtaining device 699 state information for debug and analysis. As this is a general access 700 mechanism, users of this option would have specific knowledge of the 701 device they want to access. 702 703 If you don't require the option or are in doubt, say N. 704 705config X86_RDC321X 706 bool "RDC R-321x SoC" 707 depends on X86_32 708 depends on X86_EXTENDED_PLATFORM 709 select M486 710 select X86_REBOOTFIXUPS 711 help 712 This option is needed for RDC R-321x system-on-chip, also known 713 as R-8610-(G). 714 If you don't have one of these chips, you should say N here. 715 716config X86_32_NON_STANDARD 717 bool "Support non-standard 32-bit SMP architectures" 718 depends on X86_32 && SMP 719 depends on X86_EXTENDED_PLATFORM 720 help 721 This option compiles in the bigsmp and STA2X11 default 722 subarchitectures. It is intended for a generic binary 723 kernel. If you select them all, kernel will probe it one by 724 one and will fallback to default. 725 726# Alphabetically sorted list of Non standard 32 bit platforms 727 728config X86_SUPPORTS_MEMORY_FAILURE 729 def_bool y 730 # MCE code calls memory_failure(): 731 depends on X86_MCE 732 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 733 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 734 depends on X86_64 || !SPARSEMEM 735 select ARCH_SUPPORTS_MEMORY_FAILURE 736 737config STA2X11 738 bool "STA2X11 Companion Chip Support" 739 depends on X86_32_NON_STANDARD && PCI 740 select SWIOTLB 741 select MFD_STA2X11 742 select GPIOLIB 743 help 744 This adds support for boards based on the STA2X11 IO-Hub, 745 a.k.a. "ConneXt". The chip is used in place of the standard 746 PC chipset, so all "standard" peripherals are missing. If this 747 option is selected the kernel will still be able to boot on 748 standard PC machines. 749 750config X86_32_IRIS 751 tristate "Eurobraille/Iris poweroff module" 752 depends on X86_32 753 help 754 The Iris machines from EuroBraille do not have APM or ACPI support 755 to shut themselves down properly. A special I/O sequence is 756 needed to do so, which is what this module does at 757 kernel shutdown. 758 759 This is only for Iris machines from EuroBraille. 760 761 If unused, say N. 762 763config SCHED_OMIT_FRAME_POINTER 764 def_bool y 765 prompt "Single-depth WCHAN output" 766 depends on X86 767 help 768 Calculate simpler /proc/<PID>/wchan values. If this option 769 is disabled then wchan values will recurse back to the 770 caller function. This provides more accurate wchan values, 771 at the expense of slightly more scheduling overhead. 772 773 If in doubt, say "Y". 774 775menuconfig HYPERVISOR_GUEST 776 bool "Linux guest support" 777 help 778 Say Y here to enable options for running Linux under various hyper- 779 visors. This option enables basic hypervisor detection and platform 780 setup. 781 782 If you say N, all options in this submenu will be skipped and 783 disabled, and Linux guest support won't be built in. 784 785if HYPERVISOR_GUEST 786 787config PARAVIRT 788 bool "Enable paravirtualization code" 789 depends on HAVE_STATIC_CALL 790 help 791 This changes the kernel so it can modify itself when it is run 792 under a hypervisor, potentially improving performance significantly 793 over full virtualization. However, when run without a hypervisor 794 the kernel is theoretically slower and slightly larger. 795 796config PARAVIRT_XXL 797 bool 798 799config PARAVIRT_DEBUG 800 bool "paravirt-ops debugging" 801 depends on PARAVIRT && DEBUG_KERNEL 802 help 803 Enable to debug paravirt_ops internals. Specifically, BUG if 804 a paravirt_op is missing when it is called. 805 806config PARAVIRT_SPINLOCKS 807 bool "Paravirtualization layer for spinlocks" 808 depends on PARAVIRT && SMP 809 help 810 Paravirtualized spinlocks allow a pvops backend to replace the 811 spinlock implementation with something virtualization-friendly 812 (for example, block the virtual CPU rather than spinning). 813 814 It has a minimal impact on native kernels and gives a nice performance 815 benefit on paravirtualized KVM / Xen kernels. 816 817 If you are unsure how to answer this question, answer Y. 818 819config X86_HV_CALLBACK_VECTOR 820 def_bool n 821 822source "arch/x86/xen/Kconfig" 823 824config KVM_GUEST 825 bool "KVM Guest support (including kvmclock)" 826 depends on PARAVIRT 827 select PARAVIRT_CLOCK 828 select ARCH_CPUIDLE_HALTPOLL 829 select X86_HV_CALLBACK_VECTOR 830 default y 831 help 832 This option enables various optimizations for running under the KVM 833 hypervisor. It includes a paravirtualized clock, so that instead 834 of relying on a PIT (or probably other) emulation by the 835 underlying device model, the host provides the guest with 836 timing infrastructure such as time of day, and system time 837 838config ARCH_CPUIDLE_HALTPOLL 839 def_bool n 840 prompt "Disable host haltpoll when loading haltpoll driver" 841 help 842 If virtualized under KVM, disable host haltpoll. 843 844config PVH 845 bool "Support for running PVH guests" 846 help 847 This option enables the PVH entry point for guest virtual machines 848 as specified in the x86/HVM direct boot ABI. 849 850config PARAVIRT_TIME_ACCOUNTING 851 bool "Paravirtual steal time accounting" 852 depends on PARAVIRT 853 help 854 Select this option to enable fine granularity task steal time 855 accounting. Time spent executing other tasks in parallel with 856 the current vCPU is discounted from the vCPU power. To account for 857 that, there can be a small performance impact. 858 859 If in doubt, say N here. 860 861config PARAVIRT_CLOCK 862 bool 863 864config JAILHOUSE_GUEST 865 bool "Jailhouse non-root cell support" 866 depends on X86_64 && PCI 867 select X86_PM_TIMER 868 help 869 This option allows to run Linux as guest in a Jailhouse non-root 870 cell. You can leave this option disabled if you only want to start 871 Jailhouse and run Linux afterwards in the root cell. 872 873config ACRN_GUEST 874 bool "ACRN Guest support" 875 depends on X86_64 876 select X86_HV_CALLBACK_VECTOR 877 help 878 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 879 a flexible, lightweight reference open-source hypervisor, built with 880 real-time and safety-criticality in mind. It is built for embedded 881 IOT with small footprint and real-time features. More details can be 882 found in https://projectacrn.org/. 883 884config INTEL_TDX_GUEST 885 bool "Intel TDX (Trust Domain Extensions) - Guest Support" 886 depends on X86_64 && CPU_SUP_INTEL 887 depends on X86_X2APIC 888 depends on EFI_STUB 889 select ARCH_HAS_CC_PLATFORM 890 select X86_MEM_ENCRYPT 891 select X86_MCE 892 select UNACCEPTED_MEMORY 893 help 894 Support running as a guest under Intel TDX. Without this support, 895 the guest kernel can not boot or run under TDX. 896 TDX includes memory encryption and integrity capabilities 897 which protect the confidentiality and integrity of guest 898 memory contents and CPU state. TDX guests are protected from 899 some attacks from the VMM. 900 901endif # HYPERVISOR_GUEST 902 903source "arch/x86/Kconfig.cpu" 904 905config HPET_TIMER 906 def_bool X86_64 907 prompt "HPET Timer Support" if X86_32 908 help 909 Use the IA-PC HPET (High Precision Event Timer) to manage 910 time in preference to the PIT and RTC, if a HPET is 911 present. 912 HPET is the next generation timer replacing legacy 8254s. 913 The HPET provides a stable time base on SMP 914 systems, unlike the TSC, but it is more expensive to access, 915 as it is off-chip. The interface used is documented 916 in the HPET spec, revision 1. 917 918 You can safely choose Y here. However, HPET will only be 919 activated if the platform and the BIOS support this feature. 920 Otherwise the 8254 will be used for timing services. 921 922 Choose N to continue using the legacy 8254 timer. 923 924config HPET_EMULATE_RTC 925 def_bool y 926 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 927 928# Mark as expert because too many people got it wrong. 929# The code disables itself when not needed. 930config DMI 931 default y 932 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 933 bool "Enable DMI scanning" if EXPERT 934 help 935 Enabled scanning of DMI to identify machine quirks. Say Y 936 here unless you have verified that your setup is not 937 affected by entries in the DMI blacklist. Required by PNP 938 BIOS code. 939 940config GART_IOMMU 941 bool "Old AMD GART IOMMU support" 942 select DMA_OPS 943 select IOMMU_HELPER 944 select SWIOTLB 945 depends on X86_64 && PCI && AMD_NB 946 help 947 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 948 GART based hardware IOMMUs. 949 950 The GART supports full DMA access for devices with 32-bit access 951 limitations, on systems with more than 3 GB. This is usually needed 952 for USB, sound, many IDE/SATA chipsets and some other devices. 953 954 Newer systems typically have a modern AMD IOMMU, supported via 955 the CONFIG_AMD_IOMMU=y config option. 956 957 In normal configurations this driver is only active when needed: 958 there's more than 3 GB of memory and the system contains a 959 32-bit limited device. 960 961 If unsure, say Y. 962 963config BOOT_VESA_SUPPORT 964 bool 965 help 966 If true, at least one selected framebuffer driver can take advantage 967 of VESA video modes set at an early boot stage via the vga= parameter. 968 969config MAXSMP 970 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 971 depends on X86_64 && SMP && DEBUG_KERNEL 972 select CPUMASK_OFFSTACK 973 help 974 Enable maximum number of CPUS and NUMA Nodes for this architecture. 975 If unsure, say N. 976 977# 978# The maximum number of CPUs supported: 979# 980# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 981# and which can be configured interactively in the 982# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 983# 984# The ranges are different on 32-bit and 64-bit kernels, depending on 985# hardware capabilities and scalability features of the kernel. 986# 987# ( If MAXSMP is enabled we just use the highest possible value and disable 988# interactive configuration. ) 989# 990 991config NR_CPUS_RANGE_BEGIN 992 int 993 default NR_CPUS_RANGE_END if MAXSMP 994 default 1 if !SMP 995 default 2 996 997config NR_CPUS_RANGE_END 998 int 999 depends on X86_32 1000 default 64 if SMP && X86_BIGSMP 1001 default 8 if SMP && !X86_BIGSMP 1002 default 1 if !SMP 1003 1004config NR_CPUS_RANGE_END 1005 int 1006 depends on X86_64 1007 default 8192 if SMP && CPUMASK_OFFSTACK 1008 default 512 if SMP && !CPUMASK_OFFSTACK 1009 default 1 if !SMP 1010 1011config NR_CPUS_DEFAULT 1012 int 1013 depends on X86_32 1014 default 32 if X86_BIGSMP 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 && !X86_32_NON_STANDARD 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_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1116 select IRQ_DOMAIN_HIERARCHY 1117 1118config X86_IO_APIC 1119 def_bool y 1120 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1121 1122config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1123 bool "Reroute for broken boot IRQs" 1124 depends on X86_IO_APIC 1125 help 1126 This option enables a workaround that fixes a source of 1127 spurious interrupts. This is recommended when threaded 1128 interrupt handling is used on systems where the generation of 1129 superfluous "boot interrupts" cannot be disabled. 1130 1131 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1132 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1133 kernel does during interrupt handling). On chipsets where this 1134 boot IRQ generation cannot be disabled, this workaround keeps 1135 the original IRQ line masked so that only the equivalent "boot 1136 IRQ" is delivered to the CPUs. The workaround also tells the 1137 kernel to set up the IRQ handler on the boot IRQ line. In this 1138 way only one interrupt is delivered to the kernel. Otherwise 1139 the spurious second interrupt may cause the kernel to bring 1140 down (vital) interrupt lines. 1141 1142 Only affects "broken" chipsets. Interrupt sharing may be 1143 increased on these systems. 1144 1145config X86_MCE 1146 bool "Machine Check / overheating reporting" 1147 select GENERIC_ALLOCATOR 1148 default y 1149 help 1150 Machine Check support allows the processor to notify the 1151 kernel if it detects a problem (e.g. overheating, data corruption). 1152 The action the kernel takes depends on the severity of the problem, 1153 ranging from warning messages to halting the machine. 1154 1155config X86_MCELOG_LEGACY 1156 bool "Support for deprecated /dev/mcelog character device" 1157 depends on X86_MCE 1158 help 1159 Enable support for /dev/mcelog which is needed by the old mcelog 1160 userspace logging daemon. Consider switching to the new generation 1161 rasdaemon solution. 1162 1163config X86_MCE_INTEL 1164 def_bool y 1165 prompt "Intel MCE features" 1166 depends on X86_MCE && X86_LOCAL_APIC 1167 help 1168 Additional support for intel specific MCE features such as 1169 the thermal monitor. 1170 1171config X86_MCE_AMD 1172 def_bool y 1173 prompt "AMD MCE features" 1174 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1175 help 1176 Additional support for AMD specific MCE features such as 1177 the DRAM Error Threshold. 1178 1179config X86_ANCIENT_MCE 1180 bool "Support for old Pentium 5 / WinChip machine checks" 1181 depends on X86_32 && X86_MCE 1182 help 1183 Include support for machine check handling on old Pentium 5 or WinChip 1184 systems. These typically need to be enabled explicitly on the command 1185 line. 1186 1187config X86_MCE_THRESHOLD 1188 depends on X86_MCE_AMD || X86_MCE_INTEL 1189 def_bool y 1190 1191config X86_MCE_INJECT 1192 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1193 tristate "Machine check injector support" 1194 help 1195 Provide support for injecting machine checks for testing purposes. 1196 If you don't know what a machine check is and you don't do kernel 1197 QA it is safe to say n. 1198 1199source "arch/x86/events/Kconfig" 1200 1201config X86_LEGACY_VM86 1202 bool "Legacy VM86 support" 1203 depends on X86_32 1204 help 1205 This option allows user programs to put the CPU into V8086 1206 mode, which is an 80286-era approximation of 16-bit real mode. 1207 1208 Some very old versions of X and/or vbetool require this option 1209 for user mode setting. Similarly, DOSEMU will use it if 1210 available to accelerate real mode DOS programs. However, any 1211 recent version of DOSEMU, X, or vbetool should be fully 1212 functional even without kernel VM86 support, as they will all 1213 fall back to software emulation. Nevertheless, if you are using 1214 a 16-bit DOS program where 16-bit performance matters, vm86 1215 mode might be faster than emulation and you might want to 1216 enable this option. 1217 1218 Note that any app that works on a 64-bit kernel is unlikely to 1219 need this option, as 64-bit kernels don't, and can't, support 1220 V8086 mode. This option is also unrelated to 16-bit protected 1221 mode and is not needed to run most 16-bit programs under Wine. 1222 1223 Enabling this option increases the complexity of the kernel 1224 and slows down exception handling a tiny bit. 1225 1226 If unsure, say N here. 1227 1228config VM86 1229 bool 1230 default X86_LEGACY_VM86 1231 1232config X86_16BIT 1233 bool "Enable support for 16-bit segments" if EXPERT 1234 default y 1235 depends on MODIFY_LDT_SYSCALL 1236 help 1237 This option is required by programs like Wine to run 16-bit 1238 protected mode legacy code on x86 processors. Disabling 1239 this option saves about 300 bytes on i386, or around 6K text 1240 plus 16K runtime memory on x86-64, 1241 1242config X86_ESPFIX32 1243 def_bool y 1244 depends on X86_16BIT && X86_32 1245 1246config X86_ESPFIX64 1247 def_bool y 1248 depends on X86_16BIT && X86_64 1249 1250config X86_VSYSCALL_EMULATION 1251 bool "Enable vsyscall emulation" if EXPERT 1252 default y 1253 depends on X86_64 1254 help 1255 This enables emulation of the legacy vsyscall page. Disabling 1256 it is roughly equivalent to booting with vsyscall=none, except 1257 that it will also disable the helpful warning if a program 1258 tries to use a vsyscall. With this option set to N, offending 1259 programs will just segfault, citing addresses of the form 1260 0xffffffffff600?00. 1261 1262 This option is required by many programs built before 2013, and 1263 care should be used even with newer programs if set to N. 1264 1265 Disabling this option saves about 7K of kernel size and 1266 possibly 4K of additional runtime pagetable memory. 1267 1268config X86_IOPL_IOPERM 1269 bool "IOPERM and IOPL Emulation" 1270 default y 1271 help 1272 This enables the ioperm() and iopl() syscalls which are necessary 1273 for legacy applications. 1274 1275 Legacy IOPL support is an overbroad mechanism which allows user 1276 space aside of accessing all 65536 I/O ports also to disable 1277 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1278 capabilities and permission from potentially active security 1279 modules. 1280 1281 The emulation restricts the functionality of the syscall to 1282 only allowing the full range I/O port access, but prevents the 1283 ability to disable interrupts from user space which would be 1284 granted if the hardware IOPL mechanism would be used. 1285 1286config TOSHIBA 1287 tristate "Toshiba Laptop support" 1288 depends on X86_32 1289 help 1290 This adds a driver to safely access the System Management Mode of 1291 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1292 not work on models with a Phoenix BIOS. The System Management Mode 1293 is used to set the BIOS and power saving options on Toshiba portables. 1294 1295 For information on utilities to make use of this driver see the 1296 Toshiba Linux utilities web site at: 1297 <http://www.buzzard.org.uk/toshiba/>. 1298 1299 Say Y if you intend to run this kernel on a Toshiba portable. 1300 Say N otherwise. 1301 1302config X86_REBOOTFIXUPS 1303 bool "Enable X86 board specific fixups for reboot" 1304 depends on X86_32 1305 help 1306 This enables chipset and/or board specific fixups to be done 1307 in order to get reboot to work correctly. This is only needed on 1308 some combinations of hardware and BIOS. The symptom, for which 1309 this config is intended, is when reboot ends with a stalled/hung 1310 system. 1311 1312 Currently, the only fixup is for the Geode machines using 1313 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1314 1315 Say Y if you want to enable the fixup. Currently, it's safe to 1316 enable this option even if you don't need it. 1317 Say N otherwise. 1318 1319config MICROCODE 1320 def_bool y 1321 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1322 1323config MICROCODE_INITRD32 1324 def_bool y 1325 depends on MICROCODE && X86_32 && BLK_DEV_INITRD 1326 1327config MICROCODE_LATE_LOADING 1328 bool "Late microcode loading (DANGEROUS)" 1329 default n 1330 depends on MICROCODE && SMP 1331 help 1332 Loading microcode late, when the system is up and executing instructions 1333 is a tricky business and should be avoided if possible. Just the sequence 1334 of synchronizing all cores and SMT threads is one fragile dance which does 1335 not guarantee that cores might not softlock after the loading. Therefore, 1336 use this at your own risk. Late loading taints the kernel unless the 1337 microcode header indicates that it is safe for late loading via the 1338 minimal revision check. This minimal revision check can be enforced on 1339 the kernel command line with "microcode.minrev=Y". 1340 1341config MICROCODE_LATE_FORCE_MINREV 1342 bool "Enforce late microcode loading minimal revision check" 1343 default n 1344 depends on MICROCODE_LATE_LOADING 1345 help 1346 To prevent that users load microcode late which modifies already 1347 in use features, newer microcode patches have a minimum revision field 1348 in the microcode header, which tells the kernel which minimum 1349 revision must be active in the CPU to safely load that new microcode 1350 late into the running system. If disabled the check will not 1351 be enforced but the kernel will be tainted when the minimal 1352 revision check fails. 1353 1354 This minimal revision check can also be controlled via the 1355 "microcode.minrev" parameter on the kernel command line. 1356 1357 If unsure say Y. 1358 1359config X86_MSR 1360 tristate "/dev/cpu/*/msr - Model-specific register support" 1361 help 1362 This device gives privileged processes access to the x86 1363 Model-Specific Registers (MSRs). It is a character device with 1364 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1365 MSR accesses are directed to a specific CPU on multi-processor 1366 systems. 1367 1368config X86_CPUID 1369 tristate "/dev/cpu/*/cpuid - CPU information support" 1370 help 1371 This device gives processes access to the x86 CPUID instruction to 1372 be executed on a specific processor. It is a character device 1373 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1374 /dev/cpu/31/cpuid. 1375 1376choice 1377 prompt "High Memory Support" 1378 default HIGHMEM4G 1379 depends on X86_32 1380 1381config NOHIGHMEM 1382 bool "off" 1383 help 1384 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1385 However, the address space of 32-bit x86 processors is only 4 1386 Gigabytes large. That means that, if you have a large amount of 1387 physical memory, not all of it can be "permanently mapped" by the 1388 kernel. The physical memory that's not permanently mapped is called 1389 "high memory". 1390 1391 If you are compiling a kernel which will never run on a machine with 1392 more than 1 Gigabyte total physical RAM, answer "off" here (default 1393 choice and suitable for most users). This will result in a "3GB/1GB" 1394 split: 3GB are mapped so that each process sees a 3GB virtual memory 1395 space and the remaining part of the 4GB virtual memory space is used 1396 by the kernel to permanently map as much physical memory as 1397 possible. 1398 1399 If the machine has between 1 and 4 Gigabytes physical RAM, then 1400 answer "4GB" here. 1401 1402 If more than 4 Gigabytes is used then answer "64GB" here. This 1403 selection turns Intel PAE (Physical Address Extension) mode on. 1404 PAE implements 3-level paging on IA32 processors. PAE is fully 1405 supported by Linux, PAE mode is implemented on all recent Intel 1406 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1407 then the kernel will not boot on CPUs that don't support PAE! 1408 1409 The actual amount of total physical memory will either be 1410 auto detected or can be forced by using a kernel command line option 1411 such as "mem=256M". (Try "man bootparam" or see the documentation of 1412 your boot loader (lilo or loadlin) about how to pass options to the 1413 kernel at boot time.) 1414 1415 If unsure, say "off". 1416 1417config HIGHMEM4G 1418 bool "4GB" 1419 help 1420 Select this if you have a 32-bit processor and between 1 and 4 1421 gigabytes of physical RAM. 1422 1423config HIGHMEM64G 1424 bool "64GB" 1425 depends on X86_HAVE_PAE 1426 select X86_PAE 1427 help 1428 Select this if you have a 32-bit processor and more than 4 1429 gigabytes of physical RAM. 1430 1431endchoice 1432 1433choice 1434 prompt "Memory split" if EXPERT 1435 default VMSPLIT_3G 1436 depends on X86_32 1437 help 1438 Select the desired split between kernel and user memory. 1439 1440 If the address range available to the kernel is less than the 1441 physical memory installed, the remaining memory will be available 1442 as "high memory". Accessing high memory is a little more costly 1443 than low memory, as it needs to be mapped into the kernel first. 1444 Note that increasing the kernel address space limits the range 1445 available to user programs, making the address space there 1446 tighter. Selecting anything other than the default 3G/1G split 1447 will also likely make your kernel incompatible with binary-only 1448 kernel modules. 1449 1450 If you are not absolutely sure what you are doing, leave this 1451 option alone! 1452 1453 config VMSPLIT_3G 1454 bool "3G/1G user/kernel split" 1455 config VMSPLIT_3G_OPT 1456 depends on !X86_PAE 1457 bool "3G/1G user/kernel split (for full 1G low memory)" 1458 config VMSPLIT_2G 1459 bool "2G/2G user/kernel split" 1460 config VMSPLIT_2G_OPT 1461 depends on !X86_PAE 1462 bool "2G/2G user/kernel split (for full 2G low memory)" 1463 config VMSPLIT_1G 1464 bool "1G/3G user/kernel split" 1465endchoice 1466 1467config PAGE_OFFSET 1468 hex 1469 default 0xB0000000 if VMSPLIT_3G_OPT 1470 default 0x80000000 if VMSPLIT_2G 1471 default 0x78000000 if VMSPLIT_2G_OPT 1472 default 0x40000000 if VMSPLIT_1G 1473 default 0xC0000000 1474 depends on X86_32 1475 1476config HIGHMEM 1477 def_bool y 1478 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1479 1480config X86_PAE 1481 bool "PAE (Physical Address Extension) Support" 1482 depends on X86_32 && X86_HAVE_PAE 1483 select PHYS_ADDR_T_64BIT 1484 select SWIOTLB 1485 help 1486 PAE is required for NX support, and furthermore enables 1487 larger swapspace support for non-overcommit purposes. It 1488 has the cost of more pagetable lookup overhead, and also 1489 consumes more pagetable space per process. 1490 1491config X86_5LEVEL 1492 bool "Enable 5-level page tables support" 1493 default y 1494 select DYNAMIC_MEMORY_LAYOUT 1495 select SPARSEMEM_VMEMMAP 1496 depends on X86_64 1497 help 1498 5-level paging enables access to larger address space: 1499 up to 128 PiB of virtual address space and 4 PiB of 1500 physical address space. 1501 1502 It will be supported by future Intel CPUs. 1503 1504 A kernel with the option enabled can be booted on machines that 1505 support 4- or 5-level paging. 1506 1507 See Documentation/arch/x86/x86_64/5level-paging.rst for more 1508 information. 1509 1510 Say N if unsure. 1511 1512config X86_DIRECT_GBPAGES 1513 def_bool y 1514 depends on X86_64 1515 help 1516 Certain kernel features effectively disable kernel 1517 linear 1 GB mappings (even if the CPU otherwise 1518 supports them), so don't confuse the user by printing 1519 that we have them enabled. 1520 1521config X86_CPA_STATISTICS 1522 bool "Enable statistic for Change Page Attribute" 1523 depends on DEBUG_FS 1524 help 1525 Expose statistics about the Change Page Attribute mechanism, which 1526 helps to determine the effectiveness of preserving large and huge 1527 page mappings when mapping protections are changed. 1528 1529config X86_MEM_ENCRYPT 1530 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1531 select DYNAMIC_PHYSICAL_MASK 1532 def_bool n 1533 1534config AMD_MEM_ENCRYPT 1535 bool "AMD Secure Memory Encryption (SME) support" 1536 depends on X86_64 && CPU_SUP_AMD 1537 depends on EFI_STUB 1538 select DMA_COHERENT_POOL 1539 select ARCH_USE_MEMREMAP_PROT 1540 select INSTRUCTION_DECODER 1541 select ARCH_HAS_CC_PLATFORM 1542 select X86_MEM_ENCRYPT 1543 select UNACCEPTED_MEMORY 1544 help 1545 Say yes to enable support for the encryption of system memory. 1546 This requires an AMD processor that supports Secure Memory 1547 Encryption (SME). 1548 1549# Common NUMA Features 1550config NUMA 1551 bool "NUMA Memory Allocation and Scheduler Support" 1552 depends on SMP 1553 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1554 default y if X86_BIGSMP 1555 select USE_PERCPU_NUMA_NODE_ID 1556 select OF_NUMA if OF 1557 help 1558 Enable NUMA (Non-Uniform Memory Access) support. 1559 1560 The kernel will try to allocate memory used by a CPU on the 1561 local memory controller of the CPU and add some more 1562 NUMA awareness to the kernel. 1563 1564 For 64-bit this is recommended if the system is Intel Core i7 1565 (or later), AMD Opteron, or EM64T NUMA. 1566 1567 For 32-bit this is only needed if you boot a 32-bit 1568 kernel on a 64-bit NUMA platform. 1569 1570 Otherwise, you should say N. 1571 1572config AMD_NUMA 1573 def_bool y 1574 prompt "Old style AMD Opteron NUMA detection" 1575 depends on X86_64 && NUMA && PCI 1576 help 1577 Enable AMD NUMA node topology detection. You should say Y here if 1578 you have a multi processor AMD system. This uses an old method to 1579 read the NUMA configuration directly from the builtin Northbridge 1580 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1581 which also takes priority if both are compiled in. 1582 1583config X86_64_ACPI_NUMA 1584 def_bool y 1585 prompt "ACPI NUMA detection" 1586 depends on X86_64 && NUMA && ACPI && PCI 1587 select ACPI_NUMA 1588 help 1589 Enable ACPI SRAT based node topology detection. 1590 1591config NUMA_EMU 1592 bool "NUMA emulation" 1593 depends on NUMA 1594 help 1595 Enable NUMA emulation. A flat machine will be split 1596 into virtual nodes when booted with "numa=fake=N", where N is the 1597 number of nodes. This is only useful for debugging. 1598 1599config NODES_SHIFT 1600 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1601 range 1 10 1602 default "10" if MAXSMP 1603 default "6" if X86_64 1604 default "3" 1605 depends on NUMA 1606 help 1607 Specify the maximum number of NUMA Nodes available on the target 1608 system. Increases memory reserved to accommodate various tables. 1609 1610config ARCH_FLATMEM_ENABLE 1611 def_bool y 1612 depends on X86_32 && !NUMA 1613 1614config ARCH_SPARSEMEM_ENABLE 1615 def_bool y 1616 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1617 select SPARSEMEM_STATIC if X86_32 1618 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1619 1620config ARCH_SPARSEMEM_DEFAULT 1621 def_bool X86_64 || (NUMA && X86_32) 1622 1623config ARCH_SELECT_MEMORY_MODEL 1624 def_bool y 1625 depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE 1626 1627config ARCH_MEMORY_PROBE 1628 bool "Enable sysfs memory/probe interface" 1629 depends on MEMORY_HOTPLUG 1630 help 1631 This option enables a sysfs memory/probe interface for testing. 1632 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1633 If you are unsure how to answer this question, answer N. 1634 1635config ARCH_PROC_KCORE_TEXT 1636 def_bool y 1637 depends on X86_64 && PROC_KCORE 1638 1639config ILLEGAL_POINTER_VALUE 1640 hex 1641 default 0 if X86_32 1642 default 0xdead000000000000 if X86_64 1643 1644config X86_PMEM_LEGACY_DEVICE 1645 bool 1646 1647config X86_PMEM_LEGACY 1648 tristate "Support non-standard NVDIMMs and ADR protected memory" 1649 depends on PHYS_ADDR_T_64BIT 1650 depends on BLK_DEV 1651 select X86_PMEM_LEGACY_DEVICE 1652 select NUMA_KEEP_MEMINFO if NUMA 1653 select LIBNVDIMM 1654 help 1655 Treat memory marked using the non-standard e820 type of 12 as used 1656 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1657 The kernel will offer these regions to the 'pmem' driver so 1658 they can be used for persistent storage. 1659 1660 Say Y if unsure. 1661 1662config HIGHPTE 1663 bool "Allocate 3rd-level pagetables from highmem" 1664 depends on HIGHMEM 1665 help 1666 The VM uses one page table entry for each page of physical memory. 1667 For systems with a lot of RAM, this can be wasteful of precious 1668 low memory. Setting this option will put user-space page table 1669 entries in high memory. 1670 1671config X86_CHECK_BIOS_CORRUPTION 1672 bool "Check for low memory corruption" 1673 help 1674 Periodically check for memory corruption in low memory, which 1675 is suspected to be caused by BIOS. Even when enabled in the 1676 configuration, it is disabled at runtime. Enable it by 1677 setting "memory_corruption_check=1" on the kernel command 1678 line. By default it scans the low 64k of memory every 60 1679 seconds; see the memory_corruption_check_size and 1680 memory_corruption_check_period parameters in 1681 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1682 1683 When enabled with the default parameters, this option has 1684 almost no overhead, as it reserves a relatively small amount 1685 of memory and scans it infrequently. It both detects corruption 1686 and prevents it from affecting the running system. 1687 1688 It is, however, intended as a diagnostic tool; if repeatable 1689 BIOS-originated corruption always affects the same memory, 1690 you can use memmap= to prevent the kernel from using that 1691 memory. 1692 1693config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1694 bool "Set the default setting of memory_corruption_check" 1695 depends on X86_CHECK_BIOS_CORRUPTION 1696 default y 1697 help 1698 Set whether the default state of memory_corruption_check is 1699 on or off. 1700 1701config MATH_EMULATION 1702 bool 1703 depends on MODIFY_LDT_SYSCALL 1704 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1705 help 1706 Linux can emulate a math coprocessor (used for floating point 1707 operations) if you don't have one. 486DX and Pentium processors have 1708 a math coprocessor built in, 486SX and 386 do not, unless you added 1709 a 487DX or 387, respectively. (The messages during boot time can 1710 give you some hints here ["man dmesg"].) Everyone needs either a 1711 coprocessor or this emulation. 1712 1713 If you don't have a math coprocessor, you need to say Y here; if you 1714 say Y here even though you have a coprocessor, the coprocessor will 1715 be used nevertheless. (This behavior can be changed with the kernel 1716 command line option "no387", which comes handy if your coprocessor 1717 is broken. Try "man bootparam" or see the documentation of your boot 1718 loader (lilo or loadlin) about how to pass options to the kernel at 1719 boot time.) This means that it is a good idea to say Y here if you 1720 intend to use this kernel on different machines. 1721 1722 More information about the internals of the Linux math coprocessor 1723 emulation can be found in <file:arch/x86/math-emu/README>. 1724 1725 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1726 kernel, it won't hurt. 1727 1728config MTRR 1729 def_bool y 1730 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1731 help 1732 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1733 the Memory Type Range Registers (MTRRs) may be used to control 1734 processor access to memory ranges. This is most useful if you have 1735 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1736 allows bus write transfers to be combined into a larger transfer 1737 before bursting over the PCI/AGP bus. This can increase performance 1738 of image write operations 2.5 times or more. Saying Y here creates a 1739 /proc/mtrr file which may be used to manipulate your processor's 1740 MTRRs. Typically the X server should use this. 1741 1742 This code has a reasonably generic interface so that similar 1743 control registers on other processors can be easily supported 1744 as well: 1745 1746 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1747 Registers (ARRs) which provide a similar functionality to MTRRs. For 1748 these, the ARRs are used to emulate the MTRRs. 1749 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1750 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1751 write-combining. All of these processors are supported by this code 1752 and it makes sense to say Y here if you have one of them. 1753 1754 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1755 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1756 can lead to all sorts of problems, so it's good to say Y here. 1757 1758 You can safely say Y even if your machine doesn't have MTRRs, you'll 1759 just add about 9 KB to your kernel. 1760 1761 See <file:Documentation/arch/x86/mtrr.rst> for more information. 1762 1763config MTRR_SANITIZER 1764 def_bool y 1765 prompt "MTRR cleanup support" 1766 depends on MTRR 1767 help 1768 Convert MTRR layout from continuous to discrete, so X drivers can 1769 add writeback entries. 1770 1771 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1772 The largest mtrr entry size for a continuous block can be set with 1773 mtrr_chunk_size. 1774 1775 If unsure, say Y. 1776 1777config MTRR_SANITIZER_ENABLE_DEFAULT 1778 int "MTRR cleanup enable value (0-1)" 1779 range 0 1 1780 default "0" 1781 depends on MTRR_SANITIZER 1782 help 1783 Enable mtrr cleanup default value 1784 1785config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1786 int "MTRR cleanup spare reg num (0-7)" 1787 range 0 7 1788 default "1" 1789 depends on MTRR_SANITIZER 1790 help 1791 mtrr cleanup spare entries default, it can be changed via 1792 mtrr_spare_reg_nr=N on the kernel command line. 1793 1794config X86_PAT 1795 def_bool y 1796 prompt "x86 PAT support" if EXPERT 1797 depends on MTRR 1798 help 1799 Use PAT attributes to setup page level cache control. 1800 1801 PATs are the modern equivalents of MTRRs and are much more 1802 flexible than MTRRs. 1803 1804 Say N here if you see bootup problems (boot crash, boot hang, 1805 spontaneous reboots) or a non-working video driver. 1806 1807 If unsure, say Y. 1808 1809config ARCH_USES_PG_UNCACHED 1810 def_bool y 1811 depends on X86_PAT 1812 1813config X86_UMIP 1814 def_bool y 1815 prompt "User Mode Instruction Prevention" if EXPERT 1816 help 1817 User Mode Instruction Prevention (UMIP) is a security feature in 1818 some x86 processors. If enabled, a general protection fault is 1819 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1820 executed in user mode. These instructions unnecessarily expose 1821 information about the hardware state. 1822 1823 The vast majority of applications do not use these instructions. 1824 For the very few that do, software emulation is provided in 1825 specific cases in protected and virtual-8086 modes. Emulated 1826 results are dummy. 1827 1828config CC_HAS_IBT 1829 # GCC >= 9 and binutils >= 2.29 1830 # Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654 1831 # Clang/LLVM >= 14 1832 # https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f 1833 # https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332 1834 def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \ 1835 (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \ 1836 $(as-instr,endbr64) 1837 1838config X86_CET 1839 def_bool n 1840 help 1841 CET features configured (Shadow stack or IBT) 1842 1843config X86_KERNEL_IBT 1844 prompt "Indirect Branch Tracking" 1845 def_bool y 1846 depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL 1847 # https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f 1848 depends on !LD_IS_LLD || LLD_VERSION >= 140000 1849 select OBJTOOL 1850 select X86_CET 1851 help 1852 Build the kernel with support for Indirect Branch Tracking, a 1853 hardware support course-grain forward-edge Control Flow Integrity 1854 protection. It enforces that all indirect calls must land on 1855 an ENDBR instruction, as such, the compiler will instrument the 1856 code with them to make this happen. 1857 1858 In addition to building the kernel with IBT, seal all functions that 1859 are not indirect call targets, avoiding them ever becoming one. 1860 1861 This requires LTO like objtool runs and will slow down the build. It 1862 does significantly reduce the number of ENDBR instructions in the 1863 kernel image. 1864 1865config X86_INTEL_MEMORY_PROTECTION_KEYS 1866 prompt "Memory Protection Keys" 1867 def_bool y 1868 # Note: only available in 64-bit mode 1869 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1870 select ARCH_USES_HIGH_VMA_FLAGS 1871 select ARCH_HAS_PKEYS 1872 help 1873 Memory Protection Keys provides a mechanism for enforcing 1874 page-based protections, but without requiring modification of the 1875 page tables when an application changes protection domains. 1876 1877 For details, see Documentation/core-api/protection-keys.rst 1878 1879 If unsure, say y. 1880 1881choice 1882 prompt "TSX enable mode" 1883 depends on CPU_SUP_INTEL 1884 default X86_INTEL_TSX_MODE_OFF 1885 help 1886 Intel's TSX (Transactional Synchronization Extensions) feature 1887 allows to optimize locking protocols through lock elision which 1888 can lead to a noticeable performance boost. 1889 1890 On the other hand it has been shown that TSX can be exploited 1891 to form side channel attacks (e.g. TAA) and chances are there 1892 will be more of those attacks discovered in the future. 1893 1894 Therefore TSX is not enabled by default (aka tsx=off). An admin 1895 might override this decision by tsx=on the command line parameter. 1896 Even with TSX enabled, the kernel will attempt to enable the best 1897 possible TAA mitigation setting depending on the microcode available 1898 for the particular machine. 1899 1900 This option allows to set the default tsx mode between tsx=on, =off 1901 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1902 details. 1903 1904 Say off if not sure, auto if TSX is in use but it should be used on safe 1905 platforms or on if TSX is in use and the security aspect of tsx is not 1906 relevant. 1907 1908config X86_INTEL_TSX_MODE_OFF 1909 bool "off" 1910 help 1911 TSX is disabled if possible - equals to tsx=off command line parameter. 1912 1913config X86_INTEL_TSX_MODE_ON 1914 bool "on" 1915 help 1916 TSX is always enabled on TSX capable HW - equals the tsx=on command 1917 line parameter. 1918 1919config X86_INTEL_TSX_MODE_AUTO 1920 bool "auto" 1921 help 1922 TSX is enabled on TSX capable HW that is believed to be safe against 1923 side channel attacks- equals the tsx=auto command line parameter. 1924endchoice 1925 1926config X86_SGX 1927 bool "Software Guard eXtensions (SGX)" 1928 depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC 1929 depends on CRYPTO=y 1930 depends on CRYPTO_SHA256=y 1931 select MMU_NOTIFIER 1932 select NUMA_KEEP_MEMINFO if NUMA 1933 select XARRAY_MULTI 1934 help 1935 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1936 that can be used by applications to set aside private regions of code 1937 and data, referred to as enclaves. An enclave's private memory can 1938 only be accessed by code running within the enclave. Accesses from 1939 outside the enclave, including other enclaves, are disallowed by 1940 hardware. 1941 1942 If unsure, say N. 1943 1944config X86_USER_SHADOW_STACK 1945 bool "X86 userspace shadow stack" 1946 depends on AS_WRUSS 1947 depends on X86_64 1948 select ARCH_USES_HIGH_VMA_FLAGS 1949 select X86_CET 1950 help 1951 Shadow stack protection is a hardware feature that detects function 1952 return address corruption. This helps mitigate ROP attacks. 1953 Applications must be enabled to use it, and old userspace does not 1954 get protection "for free". 1955 1956 CPUs supporting shadow stacks were first released in 2020. 1957 1958 See Documentation/arch/x86/shstk.rst for more information. 1959 1960 If unsure, say N. 1961 1962config INTEL_TDX_HOST 1963 bool "Intel Trust Domain Extensions (TDX) host support" 1964 depends on CPU_SUP_INTEL 1965 depends on X86_64 1966 depends on KVM_INTEL 1967 depends on X86_X2APIC 1968 select ARCH_KEEP_MEMBLOCK 1969 depends on CONTIG_ALLOC 1970 depends on !KEXEC_CORE 1971 depends on X86_MCE 1972 help 1973 Intel Trust Domain Extensions (TDX) protects guest VMs from malicious 1974 host and certain physical attacks. This option enables necessary TDX 1975 support in the host kernel to run confidential VMs. 1976 1977 If unsure, say N. 1978 1979config EFI 1980 bool "EFI runtime service support" 1981 depends on ACPI 1982 select UCS2_STRING 1983 select EFI_RUNTIME_WRAPPERS 1984 select ARCH_USE_MEMREMAP_PROT 1985 select EFI_RUNTIME_MAP if KEXEC_CORE 1986 help 1987 This enables the kernel to use EFI runtime services that are 1988 available (such as the EFI variable services). 1989 1990 This option is only useful on systems that have EFI firmware. 1991 In addition, you should use the latest ELILO loader available 1992 at <http://elilo.sourceforge.net> in order to take advantage 1993 of EFI runtime services. However, even with this option, the 1994 resultant kernel should continue to boot on existing non-EFI 1995 platforms. 1996 1997config EFI_STUB 1998 bool "EFI stub support" 1999 depends on EFI 2000 select RELOCATABLE 2001 help 2002 This kernel feature allows a bzImage to be loaded directly 2003 by EFI firmware without the use of a bootloader. 2004 2005 See Documentation/admin-guide/efi-stub.rst for more information. 2006 2007config EFI_HANDOVER_PROTOCOL 2008 bool "EFI handover protocol (DEPRECATED)" 2009 depends on EFI_STUB 2010 default y 2011 help 2012 Select this in order to include support for the deprecated EFI 2013 handover protocol, which defines alternative entry points into the 2014 EFI stub. This is a practice that has no basis in the UEFI 2015 specification, and requires a priori knowledge on the part of the 2016 bootloader about Linux/x86 specific ways of passing the command line 2017 and initrd, and where in memory those assets may be loaded. 2018 2019 If in doubt, say Y. Even though the corresponding support is not 2020 present in upstream GRUB or other bootloaders, most distros build 2021 GRUB with numerous downstream patches applied, and may rely on the 2022 handover protocol as as result. 2023 2024config EFI_MIXED 2025 bool "EFI mixed-mode support" 2026 depends on EFI_STUB && X86_64 2027 help 2028 Enabling this feature allows a 64-bit kernel to be booted 2029 on a 32-bit firmware, provided that your CPU supports 64-bit 2030 mode. 2031 2032 Note that it is not possible to boot a mixed-mode enabled 2033 kernel via the EFI boot stub - a bootloader that supports 2034 the EFI handover protocol must be used. 2035 2036 If unsure, say N. 2037 2038config EFI_FAKE_MEMMAP 2039 bool "Enable EFI fake memory map" 2040 depends on EFI 2041 help 2042 Saying Y here will enable "efi_fake_mem" boot option. By specifying 2043 this parameter, you can add arbitrary attribute to specific memory 2044 range by updating original (firmware provided) EFI memmap. This is 2045 useful for debugging of EFI memmap related feature, e.g., Address 2046 Range Mirroring feature. 2047 2048config EFI_MAX_FAKE_MEM 2049 int "maximum allowable number of ranges in efi_fake_mem boot option" 2050 depends on EFI_FAKE_MEMMAP 2051 range 1 128 2052 default 8 2053 help 2054 Maximum allowable number of ranges in efi_fake_mem boot option. 2055 Ranges can be set up to this value using comma-separated list. 2056 The default value is 8. 2057 2058config EFI_RUNTIME_MAP 2059 bool "Export EFI runtime maps to sysfs" if EXPERT 2060 depends on EFI 2061 help 2062 Export EFI runtime memory regions to /sys/firmware/efi/runtime-map. 2063 That memory map is required by the 2nd kernel to set up EFI virtual 2064 mappings after kexec, but can also be used for debugging purposes. 2065 2066 See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map. 2067 2068source "kernel/Kconfig.hz" 2069 2070config ARCH_SUPPORTS_KEXEC 2071 def_bool y 2072 2073config ARCH_SUPPORTS_KEXEC_FILE 2074 def_bool X86_64 2075 2076config ARCH_SELECTS_KEXEC_FILE 2077 def_bool y 2078 depends on KEXEC_FILE 2079 select HAVE_IMA_KEXEC if IMA 2080 2081config ARCH_SUPPORTS_KEXEC_PURGATORY 2082 def_bool y 2083 2084config ARCH_SUPPORTS_KEXEC_SIG 2085 def_bool y 2086 2087config ARCH_SUPPORTS_KEXEC_SIG_FORCE 2088 def_bool y 2089 2090config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG 2091 def_bool y 2092 2093config ARCH_SUPPORTS_KEXEC_JUMP 2094 def_bool y 2095 2096config ARCH_SUPPORTS_CRASH_DUMP 2097 def_bool X86_64 || (X86_32 && HIGHMEM) 2098 2099config ARCH_SUPPORTS_CRASH_HOTPLUG 2100 def_bool y 2101 2102config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION 2103 def_bool CRASH_RESERVE 2104 2105config PHYSICAL_START 2106 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2107 default "0x1000000" 2108 help 2109 This gives the physical address where the kernel is loaded. 2110 2111 If the kernel is not relocatable (CONFIG_RELOCATABLE=n) then bzImage 2112 will decompress itself to above physical address and run from there. 2113 Otherwise, bzImage will run from the address where it has been loaded 2114 by the boot loader. The only exception is if it is loaded below the 2115 above physical address, in which case it will relocate itself there. 2116 2117 In normal kdump cases one does not have to set/change this option 2118 as now bzImage can be compiled as a completely relocatable image 2119 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2120 address. This option is mainly useful for the folks who don't want 2121 to use a bzImage for capturing the crash dump and want to use a 2122 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2123 to be specifically compiled to run from a specific memory area 2124 (normally a reserved region) and this option comes handy. 2125 2126 So if you are using bzImage for capturing the crash dump, 2127 leave the value here unchanged to 0x1000000 and set 2128 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2129 for capturing the crash dump change this value to start of 2130 the reserved region. In other words, it can be set based on 2131 the "X" value as specified in the "crashkernel=YM@XM" 2132 command line boot parameter passed to the panic-ed 2133 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2134 for more details about crash dumps. 2135 2136 Usage of bzImage for capturing the crash dump is recommended as 2137 one does not have to build two kernels. Same kernel can be used 2138 as production kernel and capture kernel. Above option should have 2139 gone away after relocatable bzImage support is introduced. But it 2140 is present because there are users out there who continue to use 2141 vmlinux for dump capture. This option should go away down the 2142 line. 2143 2144 Don't change this unless you know what you are doing. 2145 2146config RELOCATABLE 2147 bool "Build a relocatable kernel" 2148 default y 2149 help 2150 This builds a kernel image that retains relocation information 2151 so it can be loaded someplace besides the default 1MB. 2152 The relocations tend to make the kernel binary about 10% larger, 2153 but are discarded at runtime. 2154 2155 One use is for the kexec on panic case where the recovery kernel 2156 must live at a different physical address than the primary 2157 kernel. 2158 2159 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2160 it has been loaded at and the compile time physical address 2161 (CONFIG_PHYSICAL_START) is used as the minimum location. 2162 2163config RANDOMIZE_BASE 2164 bool "Randomize the address of the kernel image (KASLR)" 2165 depends on RELOCATABLE 2166 default y 2167 help 2168 In support of Kernel Address Space Layout Randomization (KASLR), 2169 this randomizes the physical address at which the kernel image 2170 is decompressed and the virtual address where the kernel 2171 image is mapped, as a security feature that deters exploit 2172 attempts relying on knowledge of the location of kernel 2173 code internals. 2174 2175 On 64-bit, the kernel physical and virtual addresses are 2176 randomized separately. The physical address will be anywhere 2177 between 16MB and the top of physical memory (up to 64TB). The 2178 virtual address will be randomized from 16MB up to 1GB (9 bits 2179 of entropy). Note that this also reduces the memory space 2180 available to kernel modules from 1.5GB to 1GB. 2181 2182 On 32-bit, the kernel physical and virtual addresses are 2183 randomized together. They will be randomized from 16MB up to 2184 512MB (8 bits of entropy). 2185 2186 Entropy is generated using the RDRAND instruction if it is 2187 supported. If RDTSC is supported, its value is mixed into 2188 the entropy pool as well. If neither RDRAND nor RDTSC are 2189 supported, then entropy is read from the i8254 timer. The 2190 usable entropy is limited by the kernel being built using 2191 2GB addressing, and that PHYSICAL_ALIGN must be at a 2192 minimum of 2MB. As a result, only 10 bits of entropy are 2193 theoretically possible, but the implementations are further 2194 limited due to memory layouts. 2195 2196 If unsure, say Y. 2197 2198# Relocation on x86 needs some additional build support 2199config X86_NEED_RELOCS 2200 def_bool y 2201 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2202 2203config PHYSICAL_ALIGN 2204 hex "Alignment value to which kernel should be aligned" 2205 default "0x200000" 2206 range 0x2000 0x1000000 if X86_32 2207 range 0x200000 0x1000000 if X86_64 2208 help 2209 This value puts the alignment restrictions on physical address 2210 where kernel is loaded and run from. Kernel is compiled for an 2211 address which meets above alignment restriction. 2212 2213 If bootloader loads the kernel at a non-aligned address and 2214 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2215 address aligned to above value and run from there. 2216 2217 If bootloader loads the kernel at a non-aligned address and 2218 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2219 load address and decompress itself to the address it has been 2220 compiled for and run from there. The address for which kernel is 2221 compiled already meets above alignment restrictions. Hence the 2222 end result is that kernel runs from a physical address meeting 2223 above alignment restrictions. 2224 2225 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2226 this value must be a multiple of 0x200000. 2227 2228 Don't change this unless you know what you are doing. 2229 2230config DYNAMIC_MEMORY_LAYOUT 2231 bool 2232 help 2233 This option makes base addresses of vmalloc and vmemmap as well as 2234 __PAGE_OFFSET movable during boot. 2235 2236config RANDOMIZE_MEMORY 2237 bool "Randomize the kernel memory sections" 2238 depends on X86_64 2239 depends on RANDOMIZE_BASE 2240 select DYNAMIC_MEMORY_LAYOUT 2241 default RANDOMIZE_BASE 2242 help 2243 Randomizes the base virtual address of kernel memory sections 2244 (physical memory mapping, vmalloc & vmemmap). This security feature 2245 makes exploits relying on predictable memory locations less reliable. 2246 2247 The order of allocations remains unchanged. Entropy is generated in 2248 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2249 configuration have in average 30,000 different possible virtual 2250 addresses for each memory section. 2251 2252 If unsure, say Y. 2253 2254config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2255 hex "Physical memory mapping padding" if EXPERT 2256 depends on RANDOMIZE_MEMORY 2257 default "0xa" if MEMORY_HOTPLUG 2258 default "0x0" 2259 range 0x1 0x40 if MEMORY_HOTPLUG 2260 range 0x0 0x40 2261 help 2262 Define the padding in terabytes added to the existing physical 2263 memory size during kernel memory randomization. It is useful 2264 for memory hotplug support but reduces the entropy available for 2265 address randomization. 2266 2267 If unsure, leave at the default value. 2268 2269config ADDRESS_MASKING 2270 bool "Linear Address Masking support" 2271 depends on X86_64 2272 help 2273 Linear Address Masking (LAM) modifies the checking that is applied 2274 to 64-bit linear addresses, allowing software to use of the 2275 untranslated address bits for metadata. 2276 2277 The capability can be used for efficient address sanitizers (ASAN) 2278 implementation and for optimizations in JITs. 2279 2280config HOTPLUG_CPU 2281 def_bool y 2282 depends on SMP 2283 2284config COMPAT_VDSO 2285 def_bool n 2286 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2287 depends on COMPAT_32 2288 help 2289 Certain buggy versions of glibc will crash if they are 2290 presented with a 32-bit vDSO that is not mapped at the address 2291 indicated in its segment table. 2292 2293 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2294 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2295 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2296 the only released version with the bug, but OpenSUSE 9 2297 contains a buggy "glibc 2.3.2". 2298 2299 The symptom of the bug is that everything crashes on startup, saying: 2300 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2301 2302 Saying Y here changes the default value of the vdso32 boot 2303 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2304 This works around the glibc bug but hurts performance. 2305 2306 If unsure, say N: if you are compiling your own kernel, you 2307 are unlikely to be using a buggy version of glibc. 2308 2309choice 2310 prompt "vsyscall table for legacy applications" 2311 depends on X86_64 2312 default LEGACY_VSYSCALL_XONLY 2313 help 2314 Legacy user code that does not know how to find the vDSO expects 2315 to be able to issue three syscalls by calling fixed addresses in 2316 kernel space. Since this location is not randomized with ASLR, 2317 it can be used to assist security vulnerability exploitation. 2318 2319 This setting can be changed at boot time via the kernel command 2320 line parameter vsyscall=[emulate|xonly|none]. Emulate mode 2321 is deprecated and can only be enabled using the kernel command 2322 line. 2323 2324 On a system with recent enough glibc (2.14 or newer) and no 2325 static binaries, you can say None without a performance penalty 2326 to improve security. 2327 2328 If unsure, select "Emulate execution only". 2329 2330 config LEGACY_VSYSCALL_XONLY 2331 bool "Emulate execution only" 2332 help 2333 The kernel traps and emulates calls into the fixed vsyscall 2334 address mapping and does not allow reads. This 2335 configuration is recommended when userspace might use the 2336 legacy vsyscall area but support for legacy binary 2337 instrumentation of legacy code is not needed. It mitigates 2338 certain uses of the vsyscall area as an ASLR-bypassing 2339 buffer. 2340 2341 config LEGACY_VSYSCALL_NONE 2342 bool "None" 2343 help 2344 There will be no vsyscall mapping at all. This will 2345 eliminate any risk of ASLR bypass due to the vsyscall 2346 fixed address mapping. Attempts to use the vsyscalls 2347 will be reported to dmesg, so that either old or 2348 malicious userspace programs can be identified. 2349 2350endchoice 2351 2352config CMDLINE_BOOL 2353 bool "Built-in kernel command line" 2354 help 2355 Allow for specifying boot arguments to the kernel at 2356 build time. On some systems (e.g. embedded ones), it is 2357 necessary or convenient to provide some or all of the 2358 kernel boot arguments with the kernel itself (that is, 2359 to not rely on the boot loader to provide them.) 2360 2361 To compile command line arguments into the kernel, 2362 set this option to 'Y', then fill in the 2363 boot arguments in CONFIG_CMDLINE. 2364 2365 Systems with fully functional boot loaders (i.e. non-embedded) 2366 should leave this option set to 'N'. 2367 2368config CMDLINE 2369 string "Built-in kernel command string" 2370 depends on CMDLINE_BOOL 2371 default "" 2372 help 2373 Enter arguments here that should be compiled into the kernel 2374 image and used at boot time. If the boot loader provides a 2375 command line at boot time, it is appended to this string to 2376 form the full kernel command line, when the system boots. 2377 2378 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2379 change this behavior. 2380 2381 In most cases, the command line (whether built-in or provided 2382 by the boot loader) should specify the device for the root 2383 file system. 2384 2385config CMDLINE_OVERRIDE 2386 bool "Built-in command line overrides boot loader arguments" 2387 depends on CMDLINE_BOOL && CMDLINE != "" 2388 help 2389 Set this option to 'Y' to have the kernel ignore the boot loader 2390 command line, and use ONLY the built-in command line. 2391 2392 This is used to work around broken boot loaders. This should 2393 be set to 'N' under normal conditions. 2394 2395config MODIFY_LDT_SYSCALL 2396 bool "Enable the LDT (local descriptor table)" if EXPERT 2397 default y 2398 help 2399 Linux can allow user programs to install a per-process x86 2400 Local Descriptor Table (LDT) using the modify_ldt(2) system 2401 call. This is required to run 16-bit or segmented code such as 2402 DOSEMU or some Wine programs. It is also used by some very old 2403 threading libraries. 2404 2405 Enabling this feature adds a small amount of overhead to 2406 context switches and increases the low-level kernel attack 2407 surface. Disabling it removes the modify_ldt(2) system call. 2408 2409 Saying 'N' here may make sense for embedded or server kernels. 2410 2411config STRICT_SIGALTSTACK_SIZE 2412 bool "Enforce strict size checking for sigaltstack" 2413 depends on DYNAMIC_SIGFRAME 2414 help 2415 For historical reasons MINSIGSTKSZ is a constant which became 2416 already too small with AVX512 support. Add a mechanism to 2417 enforce strict checking of the sigaltstack size against the 2418 real size of the FPU frame. This option enables the check 2419 by default. It can also be controlled via the kernel command 2420 line option 'strict_sas_size' independent of this config 2421 switch. Enabling it might break existing applications which 2422 allocate a too small sigaltstack but 'work' because they 2423 never get a signal delivered. 2424 2425 Say 'N' unless you want to really enforce this check. 2426 2427source "kernel/livepatch/Kconfig" 2428 2429endmenu 2430 2431config CC_HAS_NAMED_AS 2432 def_bool CC_IS_GCC && GCC_VERSION >= 120100 2433 2434config USE_X86_SEG_SUPPORT 2435 def_bool y 2436 depends on CC_HAS_NAMED_AS 2437 # 2438 # -fsanitize=kernel-address (KASAN) is at the moment incompatible 2439 # with named address spaces - see GCC PR sanitizer/111736. 2440 # 2441 depends on !KASAN 2442 # -fsanitize=thread (KCSAN) is also incompatible. 2443 depends on !KCSAN 2444 2445config CC_HAS_SLS 2446 def_bool $(cc-option,-mharden-sls=all) 2447 2448config CC_HAS_RETURN_THUNK 2449 def_bool $(cc-option,-mfunction-return=thunk-extern) 2450 2451config CC_HAS_ENTRY_PADDING 2452 def_bool $(cc-option,-fpatchable-function-entry=16,16) 2453 2454config FUNCTION_PADDING_CFI 2455 int 2456 default 59 if FUNCTION_ALIGNMENT_64B 2457 default 27 if FUNCTION_ALIGNMENT_32B 2458 default 11 if FUNCTION_ALIGNMENT_16B 2459 default 3 if FUNCTION_ALIGNMENT_8B 2460 default 0 2461 2462# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG 2463# except Kconfig can't do arithmetic :/ 2464config FUNCTION_PADDING_BYTES 2465 int 2466 default FUNCTION_PADDING_CFI if CFI_CLANG 2467 default FUNCTION_ALIGNMENT 2468 2469config CALL_PADDING 2470 def_bool n 2471 depends on CC_HAS_ENTRY_PADDING && OBJTOOL 2472 select FUNCTION_ALIGNMENT_16B 2473 2474config FINEIBT 2475 def_bool y 2476 depends on X86_KERNEL_IBT && CFI_CLANG && MITIGATION_RETPOLINE 2477 select CALL_PADDING 2478 2479config HAVE_CALL_THUNKS 2480 def_bool y 2481 depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL 2482 2483config CALL_THUNKS 2484 def_bool n 2485 select CALL_PADDING 2486 2487config PREFIX_SYMBOLS 2488 def_bool y 2489 depends on CALL_PADDING && !CFI_CLANG 2490 2491menuconfig SPECULATION_MITIGATIONS 2492 bool "Mitigations for speculative execution vulnerabilities" 2493 default y 2494 help 2495 Say Y here to enable options which enable mitigations for 2496 speculative execution hardware vulnerabilities. 2497 2498 If you say N, all mitigations will be disabled. You really 2499 should know what you are doing to say so. 2500 2501if SPECULATION_MITIGATIONS 2502 2503config MITIGATION_PAGE_TABLE_ISOLATION 2504 bool "Remove the kernel mapping in user mode" 2505 default y 2506 depends on (X86_64 || X86_PAE) 2507 help 2508 This feature reduces the number of hardware side channels by 2509 ensuring that the majority of kernel addresses are not mapped 2510 into userspace. 2511 2512 See Documentation/arch/x86/pti.rst for more details. 2513 2514config MITIGATION_RETPOLINE 2515 bool "Avoid speculative indirect branches in kernel" 2516 select OBJTOOL if HAVE_OBJTOOL 2517 default y 2518 help 2519 Compile kernel with the retpoline compiler options to guard against 2520 kernel-to-user data leaks by avoiding speculative indirect 2521 branches. Requires a compiler with -mindirect-branch=thunk-extern 2522 support for full protection. The kernel may run slower. 2523 2524config MITIGATION_RETHUNK 2525 bool "Enable return-thunks" 2526 depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK 2527 select OBJTOOL if HAVE_OBJTOOL 2528 default y if X86_64 2529 help 2530 Compile the kernel with the return-thunks compiler option to guard 2531 against kernel-to-user data leaks by avoiding return speculation. 2532 Requires a compiler with -mfunction-return=thunk-extern 2533 support for full protection. The kernel may run slower. 2534 2535config MITIGATION_UNRET_ENTRY 2536 bool "Enable UNRET on kernel entry" 2537 depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64 2538 default y 2539 help 2540 Compile the kernel with support for the retbleed=unret mitigation. 2541 2542config MITIGATION_CALL_DEPTH_TRACKING 2543 bool "Mitigate RSB underflow with call depth tracking" 2544 depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS 2545 select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 2546 select CALL_THUNKS 2547 default y 2548 help 2549 Compile the kernel with call depth tracking to mitigate the Intel 2550 SKL Return-Speculation-Buffer (RSB) underflow issue. The 2551 mitigation is off by default and needs to be enabled on the 2552 kernel command line via the retbleed=stuff option. For 2553 non-affected systems the overhead of this option is marginal as 2554 the call depth tracking is using run-time generated call thunks 2555 in a compiler generated padding area and call patching. This 2556 increases text size by ~5%. For non affected systems this space 2557 is unused. On affected SKL systems this results in a significant 2558 performance gain over the IBRS mitigation. 2559 2560config CALL_THUNKS_DEBUG 2561 bool "Enable call thunks and call depth tracking debugging" 2562 depends on MITIGATION_CALL_DEPTH_TRACKING 2563 select FUNCTION_ALIGNMENT_32B 2564 default n 2565 help 2566 Enable call/ret counters for imbalance detection and build in 2567 a noisy dmesg about callthunks generation and call patching for 2568 trouble shooting. The debug prints need to be enabled on the 2569 kernel command line with 'debug-callthunks'. 2570 Only enable this when you are debugging call thunks as this 2571 creates a noticeable runtime overhead. If unsure say N. 2572 2573config MITIGATION_IBPB_ENTRY 2574 bool "Enable IBPB on kernel entry" 2575 depends on CPU_SUP_AMD && X86_64 2576 default y 2577 help 2578 Compile the kernel with support for the retbleed=ibpb mitigation. 2579 2580config MITIGATION_IBRS_ENTRY 2581 bool "Enable IBRS on kernel entry" 2582 depends on CPU_SUP_INTEL && X86_64 2583 default y 2584 help 2585 Compile the kernel with support for the spectre_v2=ibrs mitigation. 2586 This mitigates both spectre_v2 and retbleed at great cost to 2587 performance. 2588 2589config MITIGATION_SRSO 2590 bool "Mitigate speculative RAS overflow on AMD" 2591 depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK 2592 default y 2593 help 2594 Enable the SRSO mitigation needed on AMD Zen1-4 machines. 2595 2596config MITIGATION_SLS 2597 bool "Mitigate Straight-Line-Speculation" 2598 depends on CC_HAS_SLS && X86_64 2599 select OBJTOOL if HAVE_OBJTOOL 2600 default n 2601 help 2602 Compile the kernel with straight-line-speculation options to guard 2603 against straight line speculation. The kernel image might be slightly 2604 larger. 2605 2606config MITIGATION_GDS_FORCE 2607 bool "Force GDS Mitigation" 2608 depends on CPU_SUP_INTEL 2609 default n 2610 help 2611 Gather Data Sampling (GDS) is a hardware vulnerability which allows 2612 unprivileged speculative access to data which was previously stored in 2613 vector registers. 2614 2615 This option is equivalent to setting gather_data_sampling=force on the 2616 command line. The microcode mitigation is used if present, otherwise 2617 AVX is disabled as a mitigation. On affected systems that are missing 2618 the microcode any userspace code that unconditionally uses AVX will 2619 break with this option set. 2620 2621 Setting this option on systems not vulnerable to GDS has no effect. 2622 2623 If in doubt, say N. 2624 2625config MITIGATION_RFDS 2626 bool "RFDS Mitigation" 2627 depends on CPU_SUP_INTEL 2628 default y 2629 help 2630 Enable mitigation for Register File Data Sampling (RFDS) by default. 2631 RFDS is a hardware vulnerability which affects Intel Atom CPUs. It 2632 allows unprivileged speculative access to stale data previously 2633 stored in floating point, vector and integer registers. 2634 See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst> 2635 2636config MITIGATION_SPECTRE_BHI 2637 bool "Mitigate Spectre-BHB (Branch History Injection)" 2638 depends on CPU_SUP_INTEL 2639 default y 2640 help 2641 Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks 2642 where the branch history buffer is poisoned to speculatively steer 2643 indirect branches. 2644 See <file:Documentation/admin-guide/hw-vuln/spectre.rst> 2645 2646endif 2647 2648config ARCH_HAS_ADD_PAGES 2649 def_bool y 2650 depends on ARCH_ENABLE_MEMORY_HOTPLUG 2651 2652menu "Power management and ACPI options" 2653 2654config ARCH_HIBERNATION_HEADER 2655 def_bool y 2656 depends on HIBERNATION 2657 2658source "kernel/power/Kconfig" 2659 2660source "drivers/acpi/Kconfig" 2661 2662config X86_APM_BOOT 2663 def_bool y 2664 depends on APM 2665 2666menuconfig APM 2667 tristate "APM (Advanced Power Management) BIOS support" 2668 depends on X86_32 && PM_SLEEP 2669 help 2670 APM is a BIOS specification for saving power using several different 2671 techniques. This is mostly useful for battery powered laptops with 2672 APM compliant BIOSes. If you say Y here, the system time will be 2673 reset after a RESUME operation, the /proc/apm device will provide 2674 battery status information, and user-space programs will receive 2675 notification of APM "events" (e.g. battery status change). 2676 2677 If you select "Y" here, you can disable actual use of the APM 2678 BIOS by passing the "apm=off" option to the kernel at boot time. 2679 2680 Note that the APM support is almost completely disabled for 2681 machines with more than one CPU. 2682 2683 In order to use APM, you will need supporting software. For location 2684 and more information, read <file:Documentation/power/apm-acpi.rst> 2685 and the Battery Powered Linux mini-HOWTO, available from 2686 <http://www.tldp.org/docs.html#howto>. 2687 2688 This driver does not spin down disk drives (see the hdparm(8) 2689 manpage ("man 8 hdparm") for that), and it doesn't turn off 2690 VESA-compliant "green" monitors. 2691 2692 This driver does not support the TI 4000M TravelMate and the ACER 2693 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2694 desktop machines also don't have compliant BIOSes, and this driver 2695 may cause those machines to panic during the boot phase. 2696 2697 Generally, if you don't have a battery in your machine, there isn't 2698 much point in using this driver and you should say N. If you get 2699 random kernel OOPSes or reboots that don't seem to be related to 2700 anything, try disabling/enabling this option (or disabling/enabling 2701 APM in your BIOS). 2702 2703 Some other things you should try when experiencing seemingly random, 2704 "weird" problems: 2705 2706 1) make sure that you have enough swap space and that it is 2707 enabled. 2708 2) pass the "idle=poll" option to the kernel 2709 3) switch on floating point emulation in the kernel and pass 2710 the "no387" option to the kernel 2711 4) pass the "floppy=nodma" option to the kernel 2712 5) pass the "mem=4M" option to the kernel (thereby disabling 2713 all but the first 4 MB of RAM) 2714 6) make sure that the CPU is not over clocked. 2715 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2716 8) disable the cache from your BIOS settings 2717 9) install a fan for the video card or exchange video RAM 2718 10) install a better fan for the CPU 2719 11) exchange RAM chips 2720 12) exchange the motherboard. 2721 2722 To compile this driver as a module, choose M here: the 2723 module will be called apm. 2724 2725if APM 2726 2727config APM_IGNORE_USER_SUSPEND 2728 bool "Ignore USER SUSPEND" 2729 help 2730 This option will ignore USER SUSPEND requests. On machines with a 2731 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2732 series notebooks, it is necessary to say Y because of a BIOS bug. 2733 2734config APM_DO_ENABLE 2735 bool "Enable PM at boot time" 2736 help 2737 Enable APM features at boot time. From page 36 of the APM BIOS 2738 specification: "When disabled, the APM BIOS does not automatically 2739 power manage devices, enter the Standby State, enter the Suspend 2740 State, or take power saving steps in response to CPU Idle calls." 2741 This driver will make CPU Idle calls when Linux is idle (unless this 2742 feature is turned off -- see "Do CPU IDLE calls", below). This 2743 should always save battery power, but more complicated APM features 2744 will be dependent on your BIOS implementation. You may need to turn 2745 this option off if your computer hangs at boot time when using APM 2746 support, or if it beeps continuously instead of suspending. Turn 2747 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2748 T400CDT. This is off by default since most machines do fine without 2749 this feature. 2750 2751config APM_CPU_IDLE 2752 depends on CPU_IDLE 2753 bool "Make CPU Idle calls when idle" 2754 help 2755 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2756 On some machines, this can activate improved power savings, such as 2757 a slowed CPU clock rate, when the machine is idle. These idle calls 2758 are made after the idle loop has run for some length of time (e.g., 2759 333 mS). On some machines, this will cause a hang at boot time or 2760 whenever the CPU becomes idle. (On machines with more than one CPU, 2761 this option does nothing.) 2762 2763config APM_DISPLAY_BLANK 2764 bool "Enable console blanking using APM" 2765 help 2766 Enable console blanking using the APM. Some laptops can use this to 2767 turn off the LCD backlight when the screen blanker of the Linux 2768 virtual console blanks the screen. Note that this is only used by 2769 the virtual console screen blanker, and won't turn off the backlight 2770 when using the X Window system. This also doesn't have anything to 2771 do with your VESA-compliant power-saving monitor. Further, this 2772 option doesn't work for all laptops -- it might not turn off your 2773 backlight at all, or it might print a lot of errors to the console, 2774 especially if you are using gpm. 2775 2776config APM_ALLOW_INTS 2777 bool "Allow interrupts during APM BIOS calls" 2778 help 2779 Normally we disable external interrupts while we are making calls to 2780 the APM BIOS as a measure to lessen the effects of a badly behaving 2781 BIOS implementation. The BIOS should reenable interrupts if it 2782 needs to. Unfortunately, some BIOSes do not -- especially those in 2783 many of the newer IBM Thinkpads. If you experience hangs when you 2784 suspend, try setting this to Y. Otherwise, say N. 2785 2786endif # APM 2787 2788source "drivers/cpufreq/Kconfig" 2789 2790source "drivers/cpuidle/Kconfig" 2791 2792source "drivers/idle/Kconfig" 2793 2794endmenu 2795 2796menu "Bus options (PCI etc.)" 2797 2798choice 2799 prompt "PCI access mode" 2800 depends on X86_32 && PCI 2801 default PCI_GOANY 2802 help 2803 On PCI systems, the BIOS can be used to detect the PCI devices and 2804 determine their configuration. However, some old PCI motherboards 2805 have BIOS bugs and may crash if this is done. Also, some embedded 2806 PCI-based systems don't have any BIOS at all. Linux can also try to 2807 detect the PCI hardware directly without using the BIOS. 2808 2809 With this option, you can specify how Linux should detect the 2810 PCI devices. If you choose "BIOS", the BIOS will be used, 2811 if you choose "Direct", the BIOS won't be used, and if you 2812 choose "MMConfig", then PCI Express MMCONFIG will be used. 2813 If you choose "Any", the kernel will try MMCONFIG, then the 2814 direct access method and falls back to the BIOS if that doesn't 2815 work. If unsure, go with the default, which is "Any". 2816 2817config PCI_GOBIOS 2818 bool "BIOS" 2819 2820config PCI_GOMMCONFIG 2821 bool "MMConfig" 2822 2823config PCI_GODIRECT 2824 bool "Direct" 2825 2826config PCI_GOOLPC 2827 bool "OLPC XO-1" 2828 depends on OLPC 2829 2830config PCI_GOANY 2831 bool "Any" 2832 2833endchoice 2834 2835config PCI_BIOS 2836 def_bool y 2837 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2838 2839# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2840config PCI_DIRECT 2841 def_bool y 2842 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2843 2844config PCI_MMCONFIG 2845 bool "Support mmconfig PCI config space access" if X86_64 2846 default y 2847 depends on PCI && (ACPI || JAILHOUSE_GUEST) 2848 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2849 2850config PCI_OLPC 2851 def_bool y 2852 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2853 2854config PCI_XEN 2855 def_bool y 2856 depends on PCI && XEN 2857 2858config MMCONF_FAM10H 2859 def_bool y 2860 depends on X86_64 && PCI_MMCONFIG && ACPI 2861 2862config PCI_CNB20LE_QUIRK 2863 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2864 depends on PCI 2865 help 2866 Read the PCI windows out of the CNB20LE host bridge. This allows 2867 PCI hotplug to work on systems with the CNB20LE chipset which do 2868 not have ACPI. 2869 2870 There's no public spec for this chipset, and this functionality 2871 is known to be incomplete. 2872 2873 You should say N unless you know you need this. 2874 2875config ISA_BUS 2876 bool "ISA bus support on modern systems" if EXPERT 2877 help 2878 Expose ISA bus device drivers and options available for selection and 2879 configuration. Enable this option if your target machine has an ISA 2880 bus. ISA is an older system, displaced by PCI and newer bus 2881 architectures -- if your target machine is modern, it probably does 2882 not have an ISA bus. 2883 2884 If unsure, say N. 2885 2886# x86_64 have no ISA slots, but can have ISA-style DMA. 2887config ISA_DMA_API 2888 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2889 default y 2890 help 2891 Enables ISA-style DMA support for devices requiring such controllers. 2892 If unsure, say Y. 2893 2894if X86_32 2895 2896config ISA 2897 bool "ISA support" 2898 help 2899 Find out whether you have ISA slots on your motherboard. ISA is the 2900 name of a bus system, i.e. the way the CPU talks to the other stuff 2901 inside your box. Other bus systems are PCI, EISA, MicroChannel 2902 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2903 newer boards don't support it. If you have ISA, say Y, otherwise N. 2904 2905config SCx200 2906 tristate "NatSemi SCx200 support" 2907 help 2908 This provides basic support for National Semiconductor's 2909 (now AMD's) Geode processors. The driver probes for the 2910 PCI-IDs of several on-chip devices, so its a good dependency 2911 for other scx200_* drivers. 2912 2913 If compiled as a module, the driver is named scx200. 2914 2915config SCx200HR_TIMER 2916 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2917 depends on SCx200 2918 default y 2919 help 2920 This driver provides a clocksource built upon the on-chip 2921 27MHz high-resolution timer. Its also a workaround for 2922 NSC Geode SC-1100's buggy TSC, which loses time when the 2923 processor goes idle (as is done by the scheduler). The 2924 other workaround is idle=poll boot option. 2925 2926config OLPC 2927 bool "One Laptop Per Child support" 2928 depends on !X86_PAE 2929 select GPIOLIB 2930 select OF 2931 select OF_PROMTREE 2932 select IRQ_DOMAIN 2933 select OLPC_EC 2934 help 2935 Add support for detecting the unique features of the OLPC 2936 XO hardware. 2937 2938config OLPC_XO1_PM 2939 bool "OLPC XO-1 Power Management" 2940 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2941 help 2942 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2943 2944config OLPC_XO1_RTC 2945 bool "OLPC XO-1 Real Time Clock" 2946 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2947 help 2948 Add support for the XO-1 real time clock, which can be used as a 2949 programmable wakeup source. 2950 2951config OLPC_XO1_SCI 2952 bool "OLPC XO-1 SCI extras" 2953 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2954 depends on INPUT=y 2955 select POWER_SUPPLY 2956 help 2957 Add support for SCI-based features of the OLPC XO-1 laptop: 2958 - EC-driven system wakeups 2959 - Power button 2960 - Ebook switch 2961 - Lid switch 2962 - AC adapter status updates 2963 - Battery status updates 2964 2965config OLPC_XO15_SCI 2966 bool "OLPC XO-1.5 SCI extras" 2967 depends on OLPC && ACPI 2968 select POWER_SUPPLY 2969 help 2970 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2971 - EC-driven system wakeups 2972 - AC adapter status updates 2973 - Battery status updates 2974 2975config ALIX 2976 bool "PCEngines ALIX System Support (LED setup)" 2977 select GPIOLIB 2978 help 2979 This option enables system support for the PCEngines ALIX. 2980 At present this just sets up LEDs for GPIO control on 2981 ALIX2/3/6 boards. However, other system specific setup should 2982 get added here. 2983 2984 Note: You must still enable the drivers for GPIO and LED support 2985 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2986 2987 Note: You have to set alix.force=1 for boards with Award BIOS. 2988 2989config NET5501 2990 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2991 select GPIOLIB 2992 help 2993 This option enables system support for the Soekris Engineering net5501. 2994 2995config GEOS 2996 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2997 select GPIOLIB 2998 depends on DMI 2999 help 3000 This option enables system support for the Traverse Technologies GEOS. 3001 3002config TS5500 3003 bool "Technologic Systems TS-5500 platform support" 3004 depends on MELAN 3005 select CHECK_SIGNATURE 3006 select NEW_LEDS 3007 select LEDS_CLASS 3008 help 3009 This option enables system support for the Technologic Systems TS-5500. 3010 3011endif # X86_32 3012 3013config AMD_NB 3014 def_bool y 3015 depends on CPU_SUP_AMD && PCI 3016 3017endmenu 3018 3019menu "Binary Emulations" 3020 3021config IA32_EMULATION 3022 bool "IA32 Emulation" 3023 depends on X86_64 3024 select ARCH_WANT_OLD_COMPAT_IPC 3025 select BINFMT_ELF 3026 select COMPAT_OLD_SIGACTION 3027 help 3028 Include code to run legacy 32-bit programs under a 3029 64-bit kernel. You should likely turn this on, unless you're 3030 100% sure that you don't have any 32-bit programs left. 3031 3032config IA32_EMULATION_DEFAULT_DISABLED 3033 bool "IA32 emulation disabled by default" 3034 default n 3035 depends on IA32_EMULATION 3036 help 3037 Make IA32 emulation disabled by default. This prevents loading 32-bit 3038 processes and access to 32-bit syscalls. If unsure, leave it to its 3039 default value. 3040 3041config X86_X32_ABI 3042 bool "x32 ABI for 64-bit mode" 3043 depends on X86_64 3044 # llvm-objcopy does not convert x86_64 .note.gnu.property or 3045 # compressed debug sections to x86_x32 properly: 3046 # https://github.com/ClangBuiltLinux/linux/issues/514 3047 # https://github.com/ClangBuiltLinux/linux/issues/1141 3048 depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm) 3049 help 3050 Include code to run binaries for the x32 native 32-bit ABI 3051 for 64-bit processors. An x32 process gets access to the 3052 full 64-bit register file and wide data path while leaving 3053 pointers at 32 bits for smaller memory footprint. 3054 3055config COMPAT_32 3056 def_bool y 3057 depends on IA32_EMULATION || X86_32 3058 select HAVE_UID16 3059 select OLD_SIGSUSPEND3 3060 3061config COMPAT 3062 def_bool y 3063 depends on IA32_EMULATION || X86_X32_ABI 3064 3065config COMPAT_FOR_U64_ALIGNMENT 3066 def_bool y 3067 depends on COMPAT 3068 3069endmenu 3070 3071config HAVE_ATOMIC_IOMAP 3072 def_bool y 3073 depends on X86_32 3074 3075source "arch/x86/kvm/Kconfig" 3076 3077source "arch/x86/Kconfig.assembler" 3078