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_USE_CMPXCHG_LOCKREF 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 ARCH_32BIT_OFF_T if X86_32 63 select ARCH_CLOCKSOURCE_INIT 64 select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 65 select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION 66 select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64 67 select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG 68 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE) 69 select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE 70 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 71 select ARCH_HAS_CACHE_LINE_SIZE 72 select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION 73 select ARCH_HAS_CURRENT_STACK_POINTER 74 select ARCH_HAS_DEBUG_VIRTUAL 75 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 76 select ARCH_HAS_DEVMEM_IS_ALLOWED 77 select ARCH_HAS_EARLY_DEBUG if KGDB 78 select ARCH_HAS_ELF_RANDOMIZE 79 select ARCH_HAS_FAST_MULTIPLIER 80 select ARCH_HAS_FORTIFY_SOURCE 81 select ARCH_HAS_GCOV_PROFILE_ALL 82 select ARCH_HAS_KCOV if X86_64 83 select ARCH_HAS_MEM_ENCRYPT 84 select ARCH_HAS_MEMBARRIER_SYNC_CORE 85 select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS 86 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 87 select ARCH_HAS_PMEM_API if X86_64 88 select ARCH_HAS_PTE_DEVMAP if X86_64 89 select ARCH_HAS_PTE_SPECIAL 90 select ARCH_HAS_NONLEAF_PMD_YOUNG if PGTABLE_LEVELS > 2 91 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 92 select ARCH_HAS_COPY_MC if X86_64 93 select ARCH_HAS_SET_MEMORY 94 select ARCH_HAS_SET_DIRECT_MAP 95 select ARCH_HAS_STRICT_KERNEL_RWX 96 select ARCH_HAS_STRICT_MODULE_RWX 97 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 98 select ARCH_HAS_SYSCALL_WRAPPER 99 select ARCH_HAS_UBSAN_SANITIZE_ALL 100 select ARCH_HAS_DEBUG_WX 101 select ARCH_HAS_ZONE_DMA_SET if EXPERT 102 select ARCH_HAVE_NMI_SAFE_CMPXCHG 103 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 104 select ARCH_MIGHT_HAVE_PC_PARPORT 105 select ARCH_MIGHT_HAVE_PC_SERIO 106 select ARCH_STACKWALK 107 select ARCH_SUPPORTS_ACPI 108 select ARCH_SUPPORTS_ATOMIC_RMW 109 select ARCH_SUPPORTS_DEBUG_PAGEALLOC 110 select ARCH_SUPPORTS_PAGE_TABLE_CHECK if X86_64 111 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 112 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 113 select ARCH_SUPPORTS_CFI_CLANG if X86_64 114 select ARCH_USES_CFI_TRAPS if X86_64 && CFI_CLANG 115 select ARCH_SUPPORTS_LTO_CLANG 116 select ARCH_SUPPORTS_LTO_CLANG_THIN 117 select ARCH_USE_BUILTIN_BSWAP 118 select ARCH_USE_MEMTEST 119 select ARCH_USE_QUEUED_RWLOCKS 120 select ARCH_USE_QUEUED_SPINLOCKS 121 select ARCH_USE_SYM_ANNOTATIONS 122 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 123 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 124 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 125 select ARCH_WANTS_NO_INSTR 126 select ARCH_WANT_GENERAL_HUGETLB 127 select ARCH_WANT_HUGE_PMD_SHARE 128 select ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP if X86_64 129 select ARCH_WANT_LD_ORPHAN_WARN 130 select ARCH_WANTS_THP_SWAP if X86_64 131 select ARCH_HAS_PARANOID_L1D_FLUSH 132 select BUILDTIME_TABLE_SORT 133 select CLKEVT_I8253 134 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 135 select CLOCKSOURCE_WATCHDOG 136 # Word-size accesses may read uninitialized data past the trailing \0 137 # in strings and cause false KMSAN reports. 138 select DCACHE_WORD_ACCESS if !KMSAN 139 select DYNAMIC_SIGFRAME 140 select EDAC_ATOMIC_SCRUB 141 select EDAC_SUPPORT 142 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 143 select GENERIC_CLOCKEVENTS_MIN_ADJUST 144 select GENERIC_CMOS_UPDATE 145 select GENERIC_CPU_AUTOPROBE 146 select GENERIC_CPU_VULNERABILITIES 147 select GENERIC_EARLY_IOREMAP 148 select GENERIC_ENTRY 149 select GENERIC_IOMAP 150 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 151 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 152 select GENERIC_IRQ_MIGRATION if SMP 153 select GENERIC_IRQ_PROBE 154 select GENERIC_IRQ_RESERVATION_MODE 155 select GENERIC_IRQ_SHOW 156 select GENERIC_PENDING_IRQ if SMP 157 select GENERIC_PTDUMP 158 select GENERIC_SMP_IDLE_THREAD 159 select GENERIC_TIME_VSYSCALL 160 select GENERIC_GETTIMEOFDAY 161 select GENERIC_VDSO_TIME_NS 162 select GUP_GET_PTE_LOW_HIGH if X86_PAE 163 select HARDIRQS_SW_RESEND 164 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 165 select HAVE_ACPI_APEI if ACPI 166 select HAVE_ACPI_APEI_NMI if ACPI 167 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 168 select HAVE_ARCH_AUDITSYSCALL 169 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 170 select HAVE_ARCH_HUGE_VMALLOC if X86_64 171 select HAVE_ARCH_JUMP_LABEL 172 select HAVE_ARCH_JUMP_LABEL_RELATIVE 173 select HAVE_ARCH_KASAN if X86_64 174 select HAVE_ARCH_KASAN_VMALLOC if X86_64 175 select HAVE_ARCH_KFENCE 176 select HAVE_ARCH_KMSAN if X86_64 177 select HAVE_ARCH_KGDB 178 select HAVE_ARCH_MMAP_RND_BITS if MMU 179 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 180 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 181 select HAVE_ARCH_PREL32_RELOCATIONS 182 select HAVE_ARCH_SECCOMP_FILTER 183 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 184 select HAVE_ARCH_STACKLEAK 185 select HAVE_ARCH_TRACEHOOK 186 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 187 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 188 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 189 select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 190 select HAVE_ARCH_VMAP_STACK if X86_64 191 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 192 select HAVE_ARCH_WITHIN_STACK_FRAMES 193 select HAVE_ASM_MODVERSIONS 194 select HAVE_CMPXCHG_DOUBLE 195 select HAVE_CMPXCHG_LOCAL 196 select HAVE_CONTEXT_TRACKING_USER if X86_64 197 select HAVE_CONTEXT_TRACKING_USER_OFFSTACK if HAVE_CONTEXT_TRACKING_USER 198 select HAVE_C_RECORDMCOUNT 199 select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL 200 select HAVE_BUILDTIME_MCOUNT_SORT 201 select HAVE_DEBUG_KMEMLEAK 202 select HAVE_DMA_CONTIGUOUS 203 select HAVE_DYNAMIC_FTRACE 204 select HAVE_DYNAMIC_FTRACE_WITH_REGS 205 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 206 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 207 select HAVE_SAMPLE_FTRACE_DIRECT if X86_64 208 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64 209 select HAVE_EBPF_JIT 210 select HAVE_EFFICIENT_UNALIGNED_ACCESS 211 select HAVE_EISA 212 select HAVE_EXIT_THREAD 213 select HAVE_FAST_GUP 214 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 215 select HAVE_FTRACE_MCOUNT_RECORD 216 select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) 217 select HAVE_FUNCTION_TRACER 218 select HAVE_GCC_PLUGINS 219 select HAVE_HW_BREAKPOINT 220 select HAVE_IOREMAP_PROT 221 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 222 select HAVE_IRQ_TIME_ACCOUNTING 223 select HAVE_JUMP_LABEL_HACK if HAVE_OBJTOOL 224 select HAVE_KERNEL_BZIP2 225 select HAVE_KERNEL_GZIP 226 select HAVE_KERNEL_LZ4 227 select HAVE_KERNEL_LZMA 228 select HAVE_KERNEL_LZO 229 select HAVE_KERNEL_XZ 230 select HAVE_KERNEL_ZSTD 231 select HAVE_KPROBES 232 select HAVE_KPROBES_ON_FTRACE 233 select HAVE_FUNCTION_ERROR_INJECTION 234 select HAVE_KRETPROBES 235 select HAVE_RETHOOK 236 select HAVE_KVM 237 select HAVE_LIVEPATCH if X86_64 238 select HAVE_MIXED_BREAKPOINTS_REGS 239 select HAVE_MOD_ARCH_SPECIFIC 240 select HAVE_MOVE_PMD 241 select HAVE_MOVE_PUD 242 select HAVE_NOINSTR_HACK if HAVE_OBJTOOL 243 select HAVE_NMI 244 select HAVE_NOINSTR_VALIDATION if HAVE_OBJTOOL 245 select HAVE_OBJTOOL if X86_64 246 select HAVE_OPTPROBES 247 select HAVE_PCSPKR_PLATFORM 248 select HAVE_PERF_EVENTS 249 select HAVE_PERF_EVENTS_NMI 250 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 251 select HAVE_PCI 252 select HAVE_PERF_REGS 253 select HAVE_PERF_USER_STACK_DUMP 254 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 255 select MMU_GATHER_MERGE_VMAS 256 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 257 select HAVE_REGS_AND_STACK_ACCESS_API 258 select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC || STACK_VALIDATION 259 select HAVE_FUNCTION_ARG_ACCESS_API 260 select HAVE_SETUP_PER_CPU_AREA 261 select HAVE_SOFTIRQ_ON_OWN_STACK 262 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 263 select HAVE_STACK_VALIDATION if HAVE_OBJTOOL 264 select HAVE_STATIC_CALL 265 select HAVE_STATIC_CALL_INLINE if HAVE_OBJTOOL 266 select HAVE_PREEMPT_DYNAMIC_CALL 267 select HAVE_RSEQ 268 select HAVE_RUST if X86_64 269 select HAVE_SYSCALL_TRACEPOINTS 270 select HAVE_UACCESS_VALIDATION if HAVE_OBJTOOL 271 select HAVE_UNSTABLE_SCHED_CLOCK 272 select HAVE_USER_RETURN_NOTIFIER 273 select HAVE_GENERIC_VDSO 274 select HOTPLUG_SMT if SMP 275 select IRQ_FORCED_THREADING 276 select NEED_PER_CPU_EMBED_FIRST_CHUNK 277 select NEED_PER_CPU_PAGE_FIRST_CHUNK 278 select NEED_SG_DMA_LENGTH 279 select PCI_DOMAINS if PCI 280 select PCI_LOCKLESS_CONFIG if PCI 281 select PERF_EVENTS 282 select RTC_LIB 283 select RTC_MC146818_LIB 284 select SPARSE_IRQ 285 select SRCU 286 select SYSCTL_EXCEPTION_TRACE 287 select THREAD_INFO_IN_TASK 288 select TRACE_IRQFLAGS_SUPPORT 289 select TRACE_IRQFLAGS_NMI_SUPPORT 290 select USER_STACKTRACE_SUPPORT 291 select HAVE_ARCH_KCSAN if X86_64 292 select X86_FEATURE_NAMES if PROC_FS 293 select PROC_PID_ARCH_STATUS if PROC_FS 294 select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX 295 select FUNCTION_ALIGNMENT_16B if X86_64 || X86_ALIGNMENT_16 296 select FUNCTION_ALIGNMENT_4B 297 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 298 select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 299 300config INSTRUCTION_DECODER 301 def_bool y 302 depends on KPROBES || PERF_EVENTS || UPROBES 303 304config OUTPUT_FORMAT 305 string 306 default "elf32-i386" if X86_32 307 default "elf64-x86-64" if X86_64 308 309config LOCKDEP_SUPPORT 310 def_bool y 311 312config STACKTRACE_SUPPORT 313 def_bool y 314 315config MMU 316 def_bool y 317 318config ARCH_MMAP_RND_BITS_MIN 319 default 28 if 64BIT 320 default 8 321 322config ARCH_MMAP_RND_BITS_MAX 323 default 32 if 64BIT 324 default 16 325 326config ARCH_MMAP_RND_COMPAT_BITS_MIN 327 default 8 328 329config ARCH_MMAP_RND_COMPAT_BITS_MAX 330 default 16 331 332config SBUS 333 bool 334 335config GENERIC_ISA_DMA 336 def_bool y 337 depends on ISA_DMA_API 338 339config GENERIC_CSUM 340 bool 341 default y if KMSAN || KASAN 342 343config GENERIC_BUG 344 def_bool y 345 depends on BUG 346 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 347 348config GENERIC_BUG_RELATIVE_POINTERS 349 bool 350 351config ARCH_MAY_HAVE_PC_FDC 352 def_bool y 353 depends on ISA_DMA_API 354 355config GENERIC_CALIBRATE_DELAY 356 def_bool y 357 358config ARCH_HAS_CPU_RELAX 359 def_bool y 360 361config ARCH_HIBERNATION_POSSIBLE 362 def_bool y 363 364config ARCH_NR_GPIO 365 int 366 default 1024 if X86_64 367 default 512 368 369config ARCH_SUSPEND_POSSIBLE 370 def_bool y 371 372config AUDIT_ARCH 373 def_bool y if X86_64 374 375config KASAN_SHADOW_OFFSET 376 hex 377 depends on KASAN 378 default 0xdffffc0000000000 379 380config HAVE_INTEL_TXT 381 def_bool y 382 depends on INTEL_IOMMU && ACPI 383 384config X86_32_SMP 385 def_bool y 386 depends on X86_32 && SMP 387 388config X86_64_SMP 389 def_bool y 390 depends on X86_64 && SMP 391 392config ARCH_SUPPORTS_UPROBES 393 def_bool y 394 395config FIX_EARLYCON_MEM 396 def_bool y 397 398config DYNAMIC_PHYSICAL_MASK 399 bool 400 401config PGTABLE_LEVELS 402 int 403 default 5 if X86_5LEVEL 404 default 4 if X86_64 405 default 3 if X86_PAE 406 default 2 407 408config CC_HAS_SANE_STACKPROTECTOR 409 bool 410 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT 411 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) 412 help 413 We have to make sure stack protector is unconditionally disabled if 414 the compiler produces broken code or if it does not let us control 415 the segment on 32-bit kernels. 416 417menu "Processor type and features" 418 419config SMP 420 bool "Symmetric multi-processing support" 421 help 422 This enables support for systems with more than one CPU. If you have 423 a system with only one CPU, say N. If you have a system with more 424 than one CPU, say Y. 425 426 If you say N here, the kernel will run on uni- and multiprocessor 427 machines, but will use only one CPU of a multiprocessor machine. If 428 you say Y here, the kernel will run on many, but not all, 429 uniprocessor machines. On a uniprocessor machine, the kernel 430 will run faster if you say N here. 431 432 Note that if you say Y here and choose architecture "586" or 433 "Pentium" under "Processor family", the kernel will not work on 486 434 architectures. Similarly, multiprocessor kernels for the "PPro" 435 architecture may not work on all Pentium based boards. 436 437 People using multiprocessor machines who say Y here should also say 438 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 439 Management" code will be disabled if you say Y here. 440 441 See also <file:Documentation/x86/i386/IO-APIC.rst>, 442 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 443 <http://www.tldp.org/docs.html#howto>. 444 445 If you don't know what to do here, say N. 446 447config X86_FEATURE_NAMES 448 bool "Processor feature human-readable names" if EMBEDDED 449 default y 450 help 451 This option compiles in a table of x86 feature bits and corresponding 452 names. This is required to support /proc/cpuinfo and a few kernel 453 messages. You can disable this to save space, at the expense of 454 making those few kernel messages show numeric feature bits instead. 455 456 If in doubt, say Y. 457 458config X86_X2APIC 459 bool "Support x2apic" 460 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 461 help 462 This enables x2apic support on CPUs that have this feature. 463 464 This allows 32-bit apic IDs (so it can support very large systems), 465 and accesses the local apic via MSRs not via mmio. 466 467 Some Intel systems circa 2022 and later are locked into x2APIC mode 468 and can not fall back to the legacy APIC modes if SGX or TDX are 469 enabled in the BIOS. They will boot with very reduced functionality 470 without enabling this option. 471 472 If you don't know what to do here, say N. 473 474config X86_MPPARSE 475 bool "Enable MPS table" if ACPI 476 default y 477 depends on X86_LOCAL_APIC 478 help 479 For old smp systems that do not have proper acpi support. Newer systems 480 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 481 482config GOLDFISH 483 def_bool y 484 depends on X86_GOLDFISH 485 486config X86_CPU_RESCTRL 487 bool "x86 CPU resource control support" 488 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 489 select KERNFS 490 select PROC_CPU_RESCTRL if PROC_FS 491 help 492 Enable x86 CPU resource control support. 493 494 Provide support for the allocation and monitoring of system resources 495 usage by the CPU. 496 497 Intel calls this Intel Resource Director Technology 498 (Intel(R) RDT). More information about RDT can be found in the 499 Intel x86 Architecture Software Developer Manual. 500 501 AMD calls this AMD Platform Quality of Service (AMD QoS). 502 More information about AMD QoS can be found in the AMD64 Technology 503 Platform Quality of Service Extensions manual. 504 505 Say N if unsure. 506 507if X86_32 508config X86_BIGSMP 509 bool "Support for big SMP systems with more than 8 CPUs" 510 depends on SMP 511 help 512 This option is needed for the systems that have more than 8 CPUs. 513 514config X86_EXTENDED_PLATFORM 515 bool "Support for extended (non-PC) x86 platforms" 516 default y 517 help 518 If you disable this option then the kernel will only support 519 standard PC platforms. (which covers the vast majority of 520 systems out there.) 521 522 If you enable this option then you'll be able to select support 523 for the following (non-PC) 32 bit x86 platforms: 524 Goldfish (Android emulator) 525 AMD Elan 526 RDC R-321x SoC 527 SGI 320/540 (Visual Workstation) 528 STA2X11-based (e.g. Northville) 529 Moorestown MID devices 530 531 If you have one of these systems, or if you want to build a 532 generic distribution kernel, say Y here - otherwise say N. 533endif # X86_32 534 535if X86_64 536config X86_EXTENDED_PLATFORM 537 bool "Support for extended (non-PC) x86 platforms" 538 default y 539 help 540 If you disable this option then the kernel will only support 541 standard PC platforms. (which covers the vast majority of 542 systems out there.) 543 544 If you enable this option then you'll be able to select support 545 for the following (non-PC) 64 bit x86 platforms: 546 Numascale NumaChip 547 ScaleMP vSMP 548 SGI Ultraviolet 549 550 If you have one of these systems, or if you want to build a 551 generic distribution kernel, say Y here - otherwise say N. 552endif # X86_64 553# This is an alphabetically sorted list of 64 bit extended platforms 554# Please maintain the alphabetic order if and when there are additions 555config X86_NUMACHIP 556 bool "Numascale NumaChip" 557 depends on X86_64 558 depends on X86_EXTENDED_PLATFORM 559 depends on NUMA 560 depends on SMP 561 depends on X86_X2APIC 562 depends on PCI_MMCONFIG 563 help 564 Adds support for Numascale NumaChip large-SMP systems. Needed to 565 enable more than ~168 cores. 566 If you don't have one of these, you should say N here. 567 568config X86_VSMP 569 bool "ScaleMP vSMP" 570 select HYPERVISOR_GUEST 571 select PARAVIRT 572 depends on X86_64 && PCI 573 depends on X86_EXTENDED_PLATFORM 574 depends on SMP 575 help 576 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 577 supposed to run on these EM64T-based machines. Only choose this option 578 if you have one of these machines. 579 580config X86_UV 581 bool "SGI Ultraviolet" 582 depends on X86_64 583 depends on X86_EXTENDED_PLATFORM 584 depends on NUMA 585 depends on EFI 586 depends on KEXEC_CORE 587 depends on X86_X2APIC 588 depends on PCI 589 help 590 This option is needed in order to support SGI Ultraviolet systems. 591 If you don't have one of these, you should say N here. 592 593# Following is an alphabetically sorted list of 32 bit extended platforms 594# Please maintain the alphabetic order if and when there are additions 595 596config X86_GOLDFISH 597 bool "Goldfish (Virtual Platform)" 598 depends on X86_EXTENDED_PLATFORM 599 help 600 Enable support for the Goldfish virtual platform used primarily 601 for Android development. Unless you are building for the Android 602 Goldfish emulator say N here. 603 604config X86_INTEL_CE 605 bool "CE4100 TV platform" 606 depends on PCI 607 depends on PCI_GODIRECT 608 depends on X86_IO_APIC 609 depends on X86_32 610 depends on X86_EXTENDED_PLATFORM 611 select X86_REBOOTFIXUPS 612 select OF 613 select OF_EARLY_FLATTREE 614 help 615 Select for the Intel CE media processor (CE4100) SOC. 616 This option compiles in support for the CE4100 SOC for settop 617 boxes and media devices. 618 619config X86_INTEL_MID 620 bool "Intel MID platform support" 621 depends on X86_EXTENDED_PLATFORM 622 depends on X86_PLATFORM_DEVICES 623 depends on PCI 624 depends on X86_64 || (PCI_GOANY && X86_32) 625 depends on X86_IO_APIC 626 select I2C 627 select DW_APB_TIMER 628 select INTEL_SCU_PCI 629 help 630 Select to build a kernel capable of supporting Intel MID (Mobile 631 Internet Device) platform systems which do not have the PCI legacy 632 interfaces. If you are building for a PC class system say N here. 633 634 Intel MID platforms are based on an Intel processor and chipset which 635 consume less power than most of the x86 derivatives. 636 637config X86_INTEL_QUARK 638 bool "Intel Quark platform support" 639 depends on X86_32 640 depends on X86_EXTENDED_PLATFORM 641 depends on X86_PLATFORM_DEVICES 642 depends on X86_TSC 643 depends on PCI 644 depends on PCI_GOANY 645 depends on X86_IO_APIC 646 select IOSF_MBI 647 select INTEL_IMR 648 select COMMON_CLK 649 help 650 Select to include support for Quark X1000 SoC. 651 Say Y here if you have a Quark based system such as the Arduino 652 compatible Intel Galileo. 653 654config X86_INTEL_LPSS 655 bool "Intel Low Power Subsystem Support" 656 depends on X86 && ACPI && PCI 657 select COMMON_CLK 658 select PINCTRL 659 select IOSF_MBI 660 help 661 Select to build support for Intel Low Power Subsystem such as 662 found on Intel Lynxpoint PCH. Selecting this option enables 663 things like clock tree (common clock framework) and pincontrol 664 which are needed by the LPSS peripheral drivers. 665 666config X86_AMD_PLATFORM_DEVICE 667 bool "AMD ACPI2Platform devices support" 668 depends on ACPI 669 select COMMON_CLK 670 select PINCTRL 671 help 672 Select to interpret AMD specific ACPI device to platform device 673 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 674 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 675 implemented under PINCTRL subsystem. 676 677config IOSF_MBI 678 tristate "Intel SoC IOSF Sideband support for SoC platforms" 679 depends on PCI 680 help 681 This option enables sideband register access support for Intel SoC 682 platforms. On these platforms the IOSF sideband is used in lieu of 683 MSR's for some register accesses, mostly but not limited to thermal 684 and power. Drivers may query the availability of this device to 685 determine if they need the sideband in order to work on these 686 platforms. The sideband is available on the following SoC products. 687 This list is not meant to be exclusive. 688 - BayTrail 689 - Braswell 690 - Quark 691 692 You should say Y if you are running a kernel on one of these SoC's. 693 694config IOSF_MBI_DEBUG 695 bool "Enable IOSF sideband access through debugfs" 696 depends on IOSF_MBI && DEBUG_FS 697 help 698 Select this option to expose the IOSF sideband access registers (MCR, 699 MDR, MCRX) through debugfs to write and read register information from 700 different units on the SoC. This is most useful for obtaining device 701 state information for debug and analysis. As this is a general access 702 mechanism, users of this option would have specific knowledge of the 703 device they want to access. 704 705 If you don't require the option or are in doubt, say N. 706 707config X86_RDC321X 708 bool "RDC R-321x SoC" 709 depends on X86_32 710 depends on X86_EXTENDED_PLATFORM 711 select M486 712 select X86_REBOOTFIXUPS 713 help 714 This option is needed for RDC R-321x system-on-chip, also known 715 as R-8610-(G). 716 If you don't have one of these chips, you should say N here. 717 718config X86_32_NON_STANDARD 719 bool "Support non-standard 32-bit SMP architectures" 720 depends on X86_32 && SMP 721 depends on X86_EXTENDED_PLATFORM 722 help 723 This option compiles in the bigsmp and STA2X11 default 724 subarchitectures. It is intended for a generic binary 725 kernel. If you select them all, kernel will probe it one by 726 one and will fallback to default. 727 728# Alphabetically sorted list of Non standard 32 bit platforms 729 730config X86_SUPPORTS_MEMORY_FAILURE 731 def_bool y 732 # MCE code calls memory_failure(): 733 depends on X86_MCE 734 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 735 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 736 depends on X86_64 || !SPARSEMEM 737 select ARCH_SUPPORTS_MEMORY_FAILURE 738 739config STA2X11 740 bool "STA2X11 Companion Chip Support" 741 depends on X86_32_NON_STANDARD && PCI 742 select SWIOTLB 743 select MFD_STA2X11 744 select GPIOLIB 745 help 746 This adds support for boards based on the STA2X11 IO-Hub, 747 a.k.a. "ConneXt". The chip is used in place of the standard 748 PC chipset, so all "standard" peripherals are missing. If this 749 option is selected the kernel will still be able to boot on 750 standard PC machines. 751 752config X86_32_IRIS 753 tristate "Eurobraille/Iris poweroff module" 754 depends on X86_32 755 help 756 The Iris machines from EuroBraille do not have APM or ACPI support 757 to shut themselves down properly. A special I/O sequence is 758 needed to do so, which is what this module does at 759 kernel shutdown. 760 761 This is only for Iris machines from EuroBraille. 762 763 If unused, say N. 764 765config SCHED_OMIT_FRAME_POINTER 766 def_bool y 767 prompt "Single-depth WCHAN output" 768 depends on X86 769 help 770 Calculate simpler /proc/<PID>/wchan values. If this option 771 is disabled then wchan values will recurse back to the 772 caller function. This provides more accurate wchan values, 773 at the expense of slightly more scheduling overhead. 774 775 If in doubt, say "Y". 776 777menuconfig HYPERVISOR_GUEST 778 bool "Linux guest support" 779 help 780 Say Y here to enable options for running Linux under various hyper- 781 visors. This option enables basic hypervisor detection and platform 782 setup. 783 784 If you say N, all options in this submenu will be skipped and 785 disabled, and Linux guest support won't be built in. 786 787if HYPERVISOR_GUEST 788 789config PARAVIRT 790 bool "Enable paravirtualization code" 791 depends on HAVE_STATIC_CALL 792 help 793 This changes the kernel so it can modify itself when it is run 794 under a hypervisor, potentially improving performance significantly 795 over full virtualization. However, when run without a hypervisor 796 the kernel is theoretically slower and slightly larger. 797 798config PARAVIRT_XXL 799 bool 800 801config PARAVIRT_DEBUG 802 bool "paravirt-ops debugging" 803 depends on PARAVIRT && DEBUG_KERNEL 804 help 805 Enable to debug paravirt_ops internals. Specifically, BUG if 806 a paravirt_op is missing when it is called. 807 808config PARAVIRT_SPINLOCKS 809 bool "Paravirtualization layer for spinlocks" 810 depends on PARAVIRT && SMP 811 help 812 Paravirtualized spinlocks allow a pvops backend to replace the 813 spinlock implementation with something virtualization-friendly 814 (for example, block the virtual CPU rather than spinning). 815 816 It has a minimal impact on native kernels and gives a nice performance 817 benefit on paravirtualized KVM / Xen kernels. 818 819 If you are unsure how to answer this question, answer Y. 820 821config X86_HV_CALLBACK_VECTOR 822 def_bool n 823 824source "arch/x86/xen/Kconfig" 825 826config KVM_GUEST 827 bool "KVM Guest support (including kvmclock)" 828 depends on PARAVIRT 829 select PARAVIRT_CLOCK 830 select ARCH_CPUIDLE_HALTPOLL 831 select X86_HV_CALLBACK_VECTOR 832 default y 833 help 834 This option enables various optimizations for running under the KVM 835 hypervisor. It includes a paravirtualized clock, so that instead 836 of relying on a PIT (or probably other) emulation by the 837 underlying device model, the host provides the guest with 838 timing infrastructure such as time of day, and system time 839 840config ARCH_CPUIDLE_HALTPOLL 841 def_bool n 842 prompt "Disable host haltpoll when loading haltpoll driver" 843 help 844 If virtualized under KVM, disable host haltpoll. 845 846config PVH 847 bool "Support for running PVH guests" 848 help 849 This option enables the PVH entry point for guest virtual machines 850 as specified in the x86/HVM direct boot ABI. 851 852config PARAVIRT_TIME_ACCOUNTING 853 bool "Paravirtual steal time accounting" 854 depends on PARAVIRT 855 help 856 Select this option to enable fine granularity task steal time 857 accounting. Time spent executing other tasks in parallel with 858 the current vCPU is discounted from the vCPU power. To account for 859 that, there can be a small performance impact. 860 861 If in doubt, say N here. 862 863config PARAVIRT_CLOCK 864 bool 865 866config JAILHOUSE_GUEST 867 bool "Jailhouse non-root cell support" 868 depends on X86_64 && PCI 869 select X86_PM_TIMER 870 help 871 This option allows to run Linux as guest in a Jailhouse non-root 872 cell. You can leave this option disabled if you only want to start 873 Jailhouse and run Linux afterwards in the root cell. 874 875config ACRN_GUEST 876 bool "ACRN Guest support" 877 depends on X86_64 878 select X86_HV_CALLBACK_VECTOR 879 help 880 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 881 a flexible, lightweight reference open-source hypervisor, built with 882 real-time and safety-criticality in mind. It is built for embedded 883 IOT with small footprint and real-time features. More details can be 884 found in https://projectacrn.org/. 885 886config INTEL_TDX_GUEST 887 bool "Intel TDX (Trust Domain Extensions) - Guest Support" 888 depends on X86_64 && CPU_SUP_INTEL 889 depends on X86_X2APIC 890 select ARCH_HAS_CC_PLATFORM 891 select X86_MEM_ENCRYPT 892 select X86_MCE 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 && CPU_SUP_INTEL 1064 select X86_INTEL_PSTATE 1065 select CPU_FREQ 1066 default y 1067 help 1068 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1069 core ordering determined at manufacturing time, which allows 1070 certain cores to reach higher turbo frequencies (when running 1071 single threaded workloads) than others. 1072 1073 Enabling this kernel feature teaches the scheduler about 1074 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1075 scheduler's CPU selection logic accordingly, so that higher 1076 overall system performance can be achieved. 1077 1078 This feature will have no effect on CPUs without this feature. 1079 1080 If unsure say Y here. 1081 1082config UP_LATE_INIT 1083 def_bool y 1084 depends on !SMP && X86_LOCAL_APIC 1085 1086config X86_UP_APIC 1087 bool "Local APIC support on uniprocessors" if !PCI_MSI 1088 default PCI_MSI 1089 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1090 help 1091 A local APIC (Advanced Programmable Interrupt Controller) is an 1092 integrated interrupt controller in the CPU. If you have a single-CPU 1093 system which has a processor with a local APIC, you can say Y here to 1094 enable and use it. If you say Y here even though your machine doesn't 1095 have a local APIC, then the kernel will still run with no slowdown at 1096 all. The local APIC supports CPU-generated self-interrupts (timer, 1097 performance counters), and the NMI watchdog which detects hard 1098 lockups. 1099 1100config X86_UP_IOAPIC 1101 bool "IO-APIC support on uniprocessors" 1102 depends on X86_UP_APIC 1103 help 1104 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1105 SMP-capable replacement for PC-style interrupt controllers. Most 1106 SMP systems and many recent uniprocessor systems have one. 1107 1108 If you have a single-CPU system with an IO-APIC, you can say Y here 1109 to use it. If you say Y here even though your machine doesn't have 1110 an IO-APIC, then the kernel will still run with no slowdown at all. 1111 1112config X86_LOCAL_APIC 1113 def_bool y 1114 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1115 select IRQ_DOMAIN_HIERARCHY 1116 1117config X86_IO_APIC 1118 def_bool y 1119 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1120 1121config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1122 bool "Reroute for broken boot IRQs" 1123 depends on X86_IO_APIC 1124 help 1125 This option enables a workaround that fixes a source of 1126 spurious interrupts. This is recommended when threaded 1127 interrupt handling is used on systems where the generation of 1128 superfluous "boot interrupts" cannot be disabled. 1129 1130 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1131 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1132 kernel does during interrupt handling). On chipsets where this 1133 boot IRQ generation cannot be disabled, this workaround keeps 1134 the original IRQ line masked so that only the equivalent "boot 1135 IRQ" is delivered to the CPUs. The workaround also tells the 1136 kernel to set up the IRQ handler on the boot IRQ line. In this 1137 way only one interrupt is delivered to the kernel. Otherwise 1138 the spurious second interrupt may cause the kernel to bring 1139 down (vital) interrupt lines. 1140 1141 Only affects "broken" chipsets. Interrupt sharing may be 1142 increased on these systems. 1143 1144config X86_MCE 1145 bool "Machine Check / overheating reporting" 1146 select GENERIC_ALLOCATOR 1147 default y 1148 help 1149 Machine Check support allows the processor to notify the 1150 kernel if it detects a problem (e.g. overheating, data corruption). 1151 The action the kernel takes depends on the severity of the problem, 1152 ranging from warning messages to halting the machine. 1153 1154config X86_MCELOG_LEGACY 1155 bool "Support for deprecated /dev/mcelog character device" 1156 depends on X86_MCE 1157 help 1158 Enable support for /dev/mcelog which is needed by the old mcelog 1159 userspace logging daemon. Consider switching to the new generation 1160 rasdaemon solution. 1161 1162config X86_MCE_INTEL 1163 def_bool y 1164 prompt "Intel MCE features" 1165 depends on X86_MCE && X86_LOCAL_APIC 1166 help 1167 Additional support for intel specific MCE features such as 1168 the thermal monitor. 1169 1170config X86_MCE_AMD 1171 def_bool y 1172 prompt "AMD MCE features" 1173 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1174 help 1175 Additional support for AMD specific MCE features such as 1176 the DRAM Error Threshold. 1177 1178config X86_ANCIENT_MCE 1179 bool "Support for old Pentium 5 / WinChip machine checks" 1180 depends on X86_32 && X86_MCE 1181 help 1182 Include support for machine check handling on old Pentium 5 or WinChip 1183 systems. These typically need to be enabled explicitly on the command 1184 line. 1185 1186config X86_MCE_THRESHOLD 1187 depends on X86_MCE_AMD || X86_MCE_INTEL 1188 def_bool y 1189 1190config X86_MCE_INJECT 1191 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1192 tristate "Machine check injector support" 1193 help 1194 Provide support for injecting machine checks for testing purposes. 1195 If you don't know what a machine check is and you don't do kernel 1196 QA it is safe to say n. 1197 1198source "arch/x86/events/Kconfig" 1199 1200config X86_LEGACY_VM86 1201 bool "Legacy VM86 support" 1202 depends on X86_32 1203 help 1204 This option allows user programs to put the CPU into V8086 1205 mode, which is an 80286-era approximation of 16-bit real mode. 1206 1207 Some very old versions of X and/or vbetool require this option 1208 for user mode setting. Similarly, DOSEMU will use it if 1209 available to accelerate real mode DOS programs. However, any 1210 recent version of DOSEMU, X, or vbetool should be fully 1211 functional even without kernel VM86 support, as they will all 1212 fall back to software emulation. Nevertheless, if you are using 1213 a 16-bit DOS program where 16-bit performance matters, vm86 1214 mode might be faster than emulation and you might want to 1215 enable this option. 1216 1217 Note that any app that works on a 64-bit kernel is unlikely to 1218 need this option, as 64-bit kernels don't, and can't, support 1219 V8086 mode. This option is also unrelated to 16-bit protected 1220 mode and is not needed to run most 16-bit programs under Wine. 1221 1222 Enabling this option increases the complexity of the kernel 1223 and slows down exception handling a tiny bit. 1224 1225 If unsure, say N here. 1226 1227config VM86 1228 bool 1229 default X86_LEGACY_VM86 1230 1231config X86_16BIT 1232 bool "Enable support for 16-bit segments" if EXPERT 1233 default y 1234 depends on MODIFY_LDT_SYSCALL 1235 help 1236 This option is required by programs like Wine to run 16-bit 1237 protected mode legacy code on x86 processors. Disabling 1238 this option saves about 300 bytes on i386, or around 6K text 1239 plus 16K runtime memory on x86-64, 1240 1241config X86_ESPFIX32 1242 def_bool y 1243 depends on X86_16BIT && X86_32 1244 1245config X86_ESPFIX64 1246 def_bool y 1247 depends on X86_16BIT && X86_64 1248 1249config X86_VSYSCALL_EMULATION 1250 bool "Enable vsyscall emulation" if EXPERT 1251 default y 1252 depends on X86_64 1253 help 1254 This enables emulation of the legacy vsyscall page. Disabling 1255 it is roughly equivalent to booting with vsyscall=none, except 1256 that it will also disable the helpful warning if a program 1257 tries to use a vsyscall. With this option set to N, offending 1258 programs will just segfault, citing addresses of the form 1259 0xffffffffff600?00. 1260 1261 This option is required by many programs built before 2013, and 1262 care should be used even with newer programs if set to N. 1263 1264 Disabling this option saves about 7K of kernel size and 1265 possibly 4K of additional runtime pagetable memory. 1266 1267config X86_IOPL_IOPERM 1268 bool "IOPERM and IOPL Emulation" 1269 default y 1270 help 1271 This enables the ioperm() and iopl() syscalls which are necessary 1272 for legacy applications. 1273 1274 Legacy IOPL support is an overbroad mechanism which allows user 1275 space aside of accessing all 65536 I/O ports also to disable 1276 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1277 capabilities and permission from potentially active security 1278 modules. 1279 1280 The emulation restricts the functionality of the syscall to 1281 only allowing the full range I/O port access, but prevents the 1282 ability to disable interrupts from user space which would be 1283 granted if the hardware IOPL mechanism would be used. 1284 1285config TOSHIBA 1286 tristate "Toshiba Laptop support" 1287 depends on X86_32 1288 help 1289 This adds a driver to safely access the System Management Mode of 1290 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1291 not work on models with a Phoenix BIOS. The System Management Mode 1292 is used to set the BIOS and power saving options on Toshiba portables. 1293 1294 For information on utilities to make use of this driver see the 1295 Toshiba Linux utilities web site at: 1296 <http://www.buzzard.org.uk/toshiba/>. 1297 1298 Say Y if you intend to run this kernel on a Toshiba portable. 1299 Say N otherwise. 1300 1301config X86_REBOOTFIXUPS 1302 bool "Enable X86 board specific fixups for reboot" 1303 depends on X86_32 1304 help 1305 This enables chipset and/or board specific fixups to be done 1306 in order to get reboot to work correctly. This is only needed on 1307 some combinations of hardware and BIOS. The symptom, for which 1308 this config is intended, is when reboot ends with a stalled/hung 1309 system. 1310 1311 Currently, the only fixup is for the Geode machines using 1312 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1313 1314 Say Y if you want to enable the fixup. Currently, it's safe to 1315 enable this option even if you don't need it. 1316 Say N otherwise. 1317 1318config MICROCODE 1319 bool "CPU microcode loading support" 1320 default y 1321 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1322 help 1323 If you say Y here, you will be able to update the microcode on 1324 Intel and AMD processors. The Intel support is for the IA32 family, 1325 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1326 AMD support is for families 0x10 and later. You will obviously need 1327 the actual microcode binary data itself which is not shipped with 1328 the Linux kernel. 1329 1330 The preferred method to load microcode from a detached initrd is described 1331 in Documentation/x86/microcode.rst. For that you need to enable 1332 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1333 initrd for microcode blobs. 1334 1335 In addition, you can build the microcode into the kernel. For that you 1336 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1337 config option. 1338 1339config MICROCODE_INTEL 1340 bool "Intel microcode loading support" 1341 depends on CPU_SUP_INTEL && MICROCODE 1342 default MICROCODE 1343 help 1344 This options enables microcode patch loading support for Intel 1345 processors. 1346 1347 For the current Intel microcode data package go to 1348 <https://downloadcenter.intel.com> and search for 1349 'Linux Processor Microcode Data File'. 1350 1351config MICROCODE_AMD 1352 bool "AMD microcode loading support" 1353 depends on CPU_SUP_AMD && MICROCODE 1354 help 1355 If you select this option, microcode patch loading support for AMD 1356 processors will be enabled. 1357 1358config MICROCODE_LATE_LOADING 1359 bool "Late microcode loading (DANGEROUS)" 1360 default n 1361 depends on MICROCODE 1362 help 1363 Loading microcode late, when the system is up and executing instructions 1364 is a tricky business and should be avoided if possible. Just the sequence 1365 of synchronizing all cores and SMT threads is one fragile dance which does 1366 not guarantee that cores might not softlock after the loading. Therefore, 1367 use this at your own risk. Late loading taints the kernel too. 1368 1369config X86_MSR 1370 tristate "/dev/cpu/*/msr - Model-specific register support" 1371 help 1372 This device gives privileged processes access to the x86 1373 Model-Specific Registers (MSRs). It is a character device with 1374 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1375 MSR accesses are directed to a specific CPU on multi-processor 1376 systems. 1377 1378config X86_CPUID 1379 tristate "/dev/cpu/*/cpuid - CPU information support" 1380 help 1381 This device gives processes access to the x86 CPUID instruction to 1382 be executed on a specific processor. It is a character device 1383 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1384 /dev/cpu/31/cpuid. 1385 1386choice 1387 prompt "High Memory Support" 1388 default HIGHMEM4G 1389 depends on X86_32 1390 1391config NOHIGHMEM 1392 bool "off" 1393 help 1394 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1395 However, the address space of 32-bit x86 processors is only 4 1396 Gigabytes large. That means that, if you have a large amount of 1397 physical memory, not all of it can be "permanently mapped" by the 1398 kernel. The physical memory that's not permanently mapped is called 1399 "high memory". 1400 1401 If you are compiling a kernel which will never run on a machine with 1402 more than 1 Gigabyte total physical RAM, answer "off" here (default 1403 choice and suitable for most users). This will result in a "3GB/1GB" 1404 split: 3GB are mapped so that each process sees a 3GB virtual memory 1405 space and the remaining part of the 4GB virtual memory space is used 1406 by the kernel to permanently map as much physical memory as 1407 possible. 1408 1409 If the machine has between 1 and 4 Gigabytes physical RAM, then 1410 answer "4GB" here. 1411 1412 If more than 4 Gigabytes is used then answer "64GB" here. This 1413 selection turns Intel PAE (Physical Address Extension) mode on. 1414 PAE implements 3-level paging on IA32 processors. PAE is fully 1415 supported by Linux, PAE mode is implemented on all recent Intel 1416 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1417 then the kernel will not boot on CPUs that don't support PAE! 1418 1419 The actual amount of total physical memory will either be 1420 auto detected or can be forced by using a kernel command line option 1421 such as "mem=256M". (Try "man bootparam" or see the documentation of 1422 your boot loader (lilo or loadlin) about how to pass options to the 1423 kernel at boot time.) 1424 1425 If unsure, say "off". 1426 1427config HIGHMEM4G 1428 bool "4GB" 1429 help 1430 Select this if you have a 32-bit processor and between 1 and 4 1431 gigabytes of physical RAM. 1432 1433config HIGHMEM64G 1434 bool "64GB" 1435 depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6 1436 select X86_PAE 1437 help 1438 Select this if you have a 32-bit processor and more than 4 1439 gigabytes of physical RAM. 1440 1441endchoice 1442 1443choice 1444 prompt "Memory split" if EXPERT 1445 default VMSPLIT_3G 1446 depends on X86_32 1447 help 1448 Select the desired split between kernel and user memory. 1449 1450 If the address range available to the kernel is less than the 1451 physical memory installed, the remaining memory will be available 1452 as "high memory". Accessing high memory is a little more costly 1453 than low memory, as it needs to be mapped into the kernel first. 1454 Note that increasing the kernel address space limits the range 1455 available to user programs, making the address space there 1456 tighter. Selecting anything other than the default 3G/1G split 1457 will also likely make your kernel incompatible with binary-only 1458 kernel modules. 1459 1460 If you are not absolutely sure what you are doing, leave this 1461 option alone! 1462 1463 config VMSPLIT_3G 1464 bool "3G/1G user/kernel split" 1465 config VMSPLIT_3G_OPT 1466 depends on !X86_PAE 1467 bool "3G/1G user/kernel split (for full 1G low memory)" 1468 config VMSPLIT_2G 1469 bool "2G/2G user/kernel split" 1470 config VMSPLIT_2G_OPT 1471 depends on !X86_PAE 1472 bool "2G/2G user/kernel split (for full 2G low memory)" 1473 config VMSPLIT_1G 1474 bool "1G/3G user/kernel split" 1475endchoice 1476 1477config PAGE_OFFSET 1478 hex 1479 default 0xB0000000 if VMSPLIT_3G_OPT 1480 default 0x80000000 if VMSPLIT_2G 1481 default 0x78000000 if VMSPLIT_2G_OPT 1482 default 0x40000000 if VMSPLIT_1G 1483 default 0xC0000000 1484 depends on X86_32 1485 1486config HIGHMEM 1487 def_bool y 1488 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1489 1490config X86_PAE 1491 bool "PAE (Physical Address Extension) Support" 1492 depends on X86_32 && !HIGHMEM4G 1493 select PHYS_ADDR_T_64BIT 1494 select SWIOTLB 1495 help 1496 PAE is required for NX support, and furthermore enables 1497 larger swapspace support for non-overcommit purposes. It 1498 has the cost of more pagetable lookup overhead, and also 1499 consumes more pagetable space per process. 1500 1501config X86_5LEVEL 1502 bool "Enable 5-level page tables support" 1503 default y 1504 select DYNAMIC_MEMORY_LAYOUT 1505 select SPARSEMEM_VMEMMAP 1506 depends on X86_64 1507 help 1508 5-level paging enables access to larger address space: 1509 upto 128 PiB of virtual address space and 4 PiB of 1510 physical address space. 1511 1512 It will be supported by future Intel CPUs. 1513 1514 A kernel with the option enabled can be booted on machines that 1515 support 4- or 5-level paging. 1516 1517 See Documentation/x86/x86_64/5level-paging.rst for more 1518 information. 1519 1520 Say N if unsure. 1521 1522config X86_DIRECT_GBPAGES 1523 def_bool y 1524 depends on X86_64 1525 help 1526 Certain kernel features effectively disable kernel 1527 linear 1 GB mappings (even if the CPU otherwise 1528 supports them), so don't confuse the user by printing 1529 that we have them enabled. 1530 1531config X86_CPA_STATISTICS 1532 bool "Enable statistic for Change Page Attribute" 1533 depends on DEBUG_FS 1534 help 1535 Expose statistics about the Change Page Attribute mechanism, which 1536 helps to determine the effectiveness of preserving large and huge 1537 page mappings when mapping protections are changed. 1538 1539config X86_MEM_ENCRYPT 1540 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1541 select DYNAMIC_PHYSICAL_MASK 1542 def_bool n 1543 1544config AMD_MEM_ENCRYPT 1545 bool "AMD Secure Memory Encryption (SME) support" 1546 depends on X86_64 && CPU_SUP_AMD 1547 select DMA_COHERENT_POOL 1548 select ARCH_USE_MEMREMAP_PROT 1549 select INSTRUCTION_DECODER 1550 select ARCH_HAS_CC_PLATFORM 1551 select X86_MEM_ENCRYPT 1552 help 1553 Say yes to enable support for the encryption of system memory. 1554 This requires an AMD processor that supports Secure Memory 1555 Encryption (SME). 1556 1557config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1558 bool "Activate AMD Secure Memory Encryption (SME) by default" 1559 depends on AMD_MEM_ENCRYPT 1560 help 1561 Say yes to have system memory encrypted by default if running on 1562 an AMD processor that supports Secure Memory Encryption (SME). 1563 1564 If set to Y, then the encryption of system memory can be 1565 deactivated with the mem_encrypt=off command line option. 1566 1567 If set to N, then the encryption of system memory can be 1568 activated with the mem_encrypt=on command line option. 1569 1570# Common NUMA Features 1571config NUMA 1572 bool "NUMA Memory Allocation and Scheduler Support" 1573 depends on SMP 1574 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1575 default y if X86_BIGSMP 1576 select USE_PERCPU_NUMA_NODE_ID 1577 help 1578 Enable NUMA (Non-Uniform Memory Access) support. 1579 1580 The kernel will try to allocate memory used by a CPU on the 1581 local memory controller of the CPU and add some more 1582 NUMA awareness to the kernel. 1583 1584 For 64-bit this is recommended if the system is Intel Core i7 1585 (or later), AMD Opteron, or EM64T NUMA. 1586 1587 For 32-bit this is only needed if you boot a 32-bit 1588 kernel on a 64-bit NUMA platform. 1589 1590 Otherwise, you should say N. 1591 1592config AMD_NUMA 1593 def_bool y 1594 prompt "Old style AMD Opteron NUMA detection" 1595 depends on X86_64 && NUMA && PCI 1596 help 1597 Enable AMD NUMA node topology detection. You should say Y here if 1598 you have a multi processor AMD system. This uses an old method to 1599 read the NUMA configuration directly from the builtin Northbridge 1600 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1601 which also takes priority if both are compiled in. 1602 1603config X86_64_ACPI_NUMA 1604 def_bool y 1605 prompt "ACPI NUMA detection" 1606 depends on X86_64 && NUMA && ACPI && PCI 1607 select ACPI_NUMA 1608 help 1609 Enable ACPI SRAT based node topology detection. 1610 1611config NUMA_EMU 1612 bool "NUMA emulation" 1613 depends on NUMA 1614 help 1615 Enable NUMA emulation. A flat machine will be split 1616 into virtual nodes when booted with "numa=fake=N", where N is the 1617 number of nodes. This is only useful for debugging. 1618 1619config NODES_SHIFT 1620 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1621 range 1 10 1622 default "10" if MAXSMP 1623 default "6" if X86_64 1624 default "3" 1625 depends on NUMA 1626 help 1627 Specify the maximum number of NUMA Nodes available on the target 1628 system. Increases memory reserved to accommodate various tables. 1629 1630config ARCH_FLATMEM_ENABLE 1631 def_bool y 1632 depends on X86_32 && !NUMA 1633 1634config ARCH_SPARSEMEM_ENABLE 1635 def_bool y 1636 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1637 select SPARSEMEM_STATIC if X86_32 1638 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1639 1640config ARCH_SPARSEMEM_DEFAULT 1641 def_bool X86_64 || (NUMA && X86_32) 1642 1643config ARCH_SELECT_MEMORY_MODEL 1644 def_bool y 1645 depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE 1646 1647config ARCH_MEMORY_PROBE 1648 bool "Enable sysfs memory/probe interface" 1649 depends on MEMORY_HOTPLUG 1650 help 1651 This option enables a sysfs memory/probe interface for testing. 1652 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1653 If you are unsure how to answer this question, answer N. 1654 1655config ARCH_PROC_KCORE_TEXT 1656 def_bool y 1657 depends on X86_64 && PROC_KCORE 1658 1659config ILLEGAL_POINTER_VALUE 1660 hex 1661 default 0 if X86_32 1662 default 0xdead000000000000 if X86_64 1663 1664config X86_PMEM_LEGACY_DEVICE 1665 bool 1666 1667config X86_PMEM_LEGACY 1668 tristate "Support non-standard NVDIMMs and ADR protected memory" 1669 depends on PHYS_ADDR_T_64BIT 1670 depends on BLK_DEV 1671 select X86_PMEM_LEGACY_DEVICE 1672 select NUMA_KEEP_MEMINFO if NUMA 1673 select LIBNVDIMM 1674 help 1675 Treat memory marked using the non-standard e820 type of 12 as used 1676 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1677 The kernel will offer these regions to the 'pmem' driver so 1678 they can be used for persistent storage. 1679 1680 Say Y if unsure. 1681 1682config HIGHPTE 1683 bool "Allocate 3rd-level pagetables from highmem" 1684 depends on HIGHMEM 1685 help 1686 The VM uses one page table entry for each page of physical memory. 1687 For systems with a lot of RAM, this can be wasteful of precious 1688 low memory. Setting this option will put user-space page table 1689 entries in high memory. 1690 1691config X86_CHECK_BIOS_CORRUPTION 1692 bool "Check for low memory corruption" 1693 help 1694 Periodically check for memory corruption in low memory, which 1695 is suspected to be caused by BIOS. Even when enabled in the 1696 configuration, it is disabled at runtime. Enable it by 1697 setting "memory_corruption_check=1" on the kernel command 1698 line. By default it scans the low 64k of memory every 60 1699 seconds; see the memory_corruption_check_size and 1700 memory_corruption_check_period parameters in 1701 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1702 1703 When enabled with the default parameters, this option has 1704 almost no overhead, as it reserves a relatively small amount 1705 of memory and scans it infrequently. It both detects corruption 1706 and prevents it from affecting the running system. 1707 1708 It is, however, intended as a diagnostic tool; if repeatable 1709 BIOS-originated corruption always affects the same memory, 1710 you can use memmap= to prevent the kernel from using that 1711 memory. 1712 1713config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1714 bool "Set the default setting of memory_corruption_check" 1715 depends on X86_CHECK_BIOS_CORRUPTION 1716 default y 1717 help 1718 Set whether the default state of memory_corruption_check is 1719 on or off. 1720 1721config MATH_EMULATION 1722 bool 1723 depends on MODIFY_LDT_SYSCALL 1724 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1725 help 1726 Linux can emulate a math coprocessor (used for floating point 1727 operations) if you don't have one. 486DX and Pentium processors have 1728 a math coprocessor built in, 486SX and 386 do not, unless you added 1729 a 487DX or 387, respectively. (The messages during boot time can 1730 give you some hints here ["man dmesg"].) Everyone needs either a 1731 coprocessor or this emulation. 1732 1733 If you don't have a math coprocessor, you need to say Y here; if you 1734 say Y here even though you have a coprocessor, the coprocessor will 1735 be used nevertheless. (This behavior can be changed with the kernel 1736 command line option "no387", which comes handy if your coprocessor 1737 is broken. Try "man bootparam" or see the documentation of your boot 1738 loader (lilo or loadlin) about how to pass options to the kernel at 1739 boot time.) This means that it is a good idea to say Y here if you 1740 intend to use this kernel on different machines. 1741 1742 More information about the internals of the Linux math coprocessor 1743 emulation can be found in <file:arch/x86/math-emu/README>. 1744 1745 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1746 kernel, it won't hurt. 1747 1748config MTRR 1749 def_bool y 1750 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1751 help 1752 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1753 the Memory Type Range Registers (MTRRs) may be used to control 1754 processor access to memory ranges. This is most useful if you have 1755 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1756 allows bus write transfers to be combined into a larger transfer 1757 before bursting over the PCI/AGP bus. This can increase performance 1758 of image write operations 2.5 times or more. Saying Y here creates a 1759 /proc/mtrr file which may be used to manipulate your processor's 1760 MTRRs. Typically the X server should use this. 1761 1762 This code has a reasonably generic interface so that similar 1763 control registers on other processors can be easily supported 1764 as well: 1765 1766 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1767 Registers (ARRs) which provide a similar functionality to MTRRs. For 1768 these, the ARRs are used to emulate the MTRRs. 1769 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1770 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1771 write-combining. All of these processors are supported by this code 1772 and it makes sense to say Y here if you have one of them. 1773 1774 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1775 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1776 can lead to all sorts of problems, so it's good to say Y here. 1777 1778 You can safely say Y even if your machine doesn't have MTRRs, you'll 1779 just add about 9 KB to your kernel. 1780 1781 See <file:Documentation/x86/mtrr.rst> for more information. 1782 1783config MTRR_SANITIZER 1784 def_bool y 1785 prompt "MTRR cleanup support" 1786 depends on MTRR 1787 help 1788 Convert MTRR layout from continuous to discrete, so X drivers can 1789 add writeback entries. 1790 1791 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1792 The largest mtrr entry size for a continuous block can be set with 1793 mtrr_chunk_size. 1794 1795 If unsure, say Y. 1796 1797config MTRR_SANITIZER_ENABLE_DEFAULT 1798 int "MTRR cleanup enable value (0-1)" 1799 range 0 1 1800 default "0" 1801 depends on MTRR_SANITIZER 1802 help 1803 Enable mtrr cleanup default value 1804 1805config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1806 int "MTRR cleanup spare reg num (0-7)" 1807 range 0 7 1808 default "1" 1809 depends on MTRR_SANITIZER 1810 help 1811 mtrr cleanup spare entries default, it can be changed via 1812 mtrr_spare_reg_nr=N on the kernel command line. 1813 1814config X86_PAT 1815 def_bool y 1816 prompt "x86 PAT support" if EXPERT 1817 depends on MTRR 1818 help 1819 Use PAT attributes to setup page level cache control. 1820 1821 PATs are the modern equivalents of MTRRs and are much more 1822 flexible than MTRRs. 1823 1824 Say N here if you see bootup problems (boot crash, boot hang, 1825 spontaneous reboots) or a non-working video driver. 1826 1827 If unsure, say Y. 1828 1829config ARCH_USES_PG_UNCACHED 1830 def_bool y 1831 depends on X86_PAT 1832 1833config X86_UMIP 1834 def_bool y 1835 prompt "User Mode Instruction Prevention" if EXPERT 1836 help 1837 User Mode Instruction Prevention (UMIP) is a security feature in 1838 some x86 processors. If enabled, a general protection fault is 1839 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1840 executed in user mode. These instructions unnecessarily expose 1841 information about the hardware state. 1842 1843 The vast majority of applications do not use these instructions. 1844 For the very few that do, software emulation is provided in 1845 specific cases in protected and virtual-8086 modes. Emulated 1846 results are dummy. 1847 1848config CC_HAS_IBT 1849 # GCC >= 9 and binutils >= 2.29 1850 # Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654 1851 # Clang/LLVM >= 14 1852 # https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f 1853 # https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332 1854 def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \ 1855 (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \ 1856 $(as-instr,endbr64) 1857 1858config X86_KERNEL_IBT 1859 prompt "Indirect Branch Tracking" 1860 def_bool y 1861 depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL 1862 # https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f 1863 depends on !LD_IS_LLD || LLD_VERSION >= 140000 1864 select OBJTOOL 1865 help 1866 Build the kernel with support for Indirect Branch Tracking, a 1867 hardware support course-grain forward-edge Control Flow Integrity 1868 protection. It enforces that all indirect calls must land on 1869 an ENDBR instruction, as such, the compiler will instrument the 1870 code with them to make this happen. 1871 1872 In addition to building the kernel with IBT, seal all functions that 1873 are not indirect call targets, avoiding them ever becoming one. 1874 1875 This requires LTO like objtool runs and will slow down the build. It 1876 does significantly reduce the number of ENDBR instructions in the 1877 kernel image. 1878 1879config X86_INTEL_MEMORY_PROTECTION_KEYS 1880 prompt "Memory Protection Keys" 1881 def_bool y 1882 # Note: only available in 64-bit mode 1883 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1884 select ARCH_USES_HIGH_VMA_FLAGS 1885 select ARCH_HAS_PKEYS 1886 help 1887 Memory Protection Keys provides a mechanism for enforcing 1888 page-based protections, but without requiring modification of the 1889 page tables when an application changes protection domains. 1890 1891 For details, see Documentation/core-api/protection-keys.rst 1892 1893 If unsure, say y. 1894 1895choice 1896 prompt "TSX enable mode" 1897 depends on CPU_SUP_INTEL 1898 default X86_INTEL_TSX_MODE_OFF 1899 help 1900 Intel's TSX (Transactional Synchronization Extensions) feature 1901 allows to optimize locking protocols through lock elision which 1902 can lead to a noticeable performance boost. 1903 1904 On the other hand it has been shown that TSX can be exploited 1905 to form side channel attacks (e.g. TAA) and chances are there 1906 will be more of those attacks discovered in the future. 1907 1908 Therefore TSX is not enabled by default (aka tsx=off). An admin 1909 might override this decision by tsx=on the command line parameter. 1910 Even with TSX enabled, the kernel will attempt to enable the best 1911 possible TAA mitigation setting depending on the microcode available 1912 for the particular machine. 1913 1914 This option allows to set the default tsx mode between tsx=on, =off 1915 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1916 details. 1917 1918 Say off if not sure, auto if TSX is in use but it should be used on safe 1919 platforms or on if TSX is in use and the security aspect of tsx is not 1920 relevant. 1921 1922config X86_INTEL_TSX_MODE_OFF 1923 bool "off" 1924 help 1925 TSX is disabled if possible - equals to tsx=off command line parameter. 1926 1927config X86_INTEL_TSX_MODE_ON 1928 bool "on" 1929 help 1930 TSX is always enabled on TSX capable HW - equals the tsx=on command 1931 line parameter. 1932 1933config X86_INTEL_TSX_MODE_AUTO 1934 bool "auto" 1935 help 1936 TSX is enabled on TSX capable HW that is believed to be safe against 1937 side channel attacks- equals the tsx=auto command line parameter. 1938endchoice 1939 1940config X86_SGX 1941 bool "Software Guard eXtensions (SGX)" 1942 depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC 1943 depends on CRYPTO=y 1944 depends on CRYPTO_SHA256=y 1945 select SRCU 1946 select MMU_NOTIFIER 1947 select NUMA_KEEP_MEMINFO if NUMA 1948 select XARRAY_MULTI 1949 help 1950 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1951 that can be used by applications to set aside private regions of code 1952 and data, referred to as enclaves. An enclave's private memory can 1953 only be accessed by code running within the enclave. Accesses from 1954 outside the enclave, including other enclaves, are disallowed by 1955 hardware. 1956 1957 If unsure, say N. 1958 1959config EFI 1960 bool "EFI runtime service support" 1961 depends on ACPI 1962 select UCS2_STRING 1963 select EFI_RUNTIME_WRAPPERS 1964 select ARCH_USE_MEMREMAP_PROT 1965 help 1966 This enables the kernel to use EFI runtime services that are 1967 available (such as the EFI variable services). 1968 1969 This option is only useful on systems that have EFI firmware. 1970 In addition, you should use the latest ELILO loader available 1971 at <http://elilo.sourceforge.net> in order to take advantage 1972 of EFI runtime services. However, even with this option, the 1973 resultant kernel should continue to boot on existing non-EFI 1974 platforms. 1975 1976config EFI_STUB 1977 bool "EFI stub support" 1978 depends on EFI 1979 select RELOCATABLE 1980 help 1981 This kernel feature allows a bzImage to be loaded directly 1982 by EFI firmware without the use of a bootloader. 1983 1984 See Documentation/admin-guide/efi-stub.rst for more information. 1985 1986config EFI_HANDOVER_PROTOCOL 1987 bool "EFI handover protocol (DEPRECATED)" 1988 depends on EFI_STUB 1989 default y 1990 help 1991 Select this in order to include support for the deprecated EFI 1992 handover protocol, which defines alternative entry points into the 1993 EFI stub. This is a practice that has no basis in the UEFI 1994 specification, and requires a priori knowledge on the part of the 1995 bootloader about Linux/x86 specific ways of passing the command line 1996 and initrd, and where in memory those assets may be loaded. 1997 1998 If in doubt, say Y. Even though the corresponding support is not 1999 present in upstream GRUB or other bootloaders, most distros build 2000 GRUB with numerous downstream patches applied, and may rely on the 2001 handover protocol as as result. 2002 2003config EFI_MIXED 2004 bool "EFI mixed-mode support" 2005 depends on EFI_STUB && X86_64 2006 help 2007 Enabling this feature allows a 64-bit kernel to be booted 2008 on a 32-bit firmware, provided that your CPU supports 64-bit 2009 mode. 2010 2011 Note that it is not possible to boot a mixed-mode enabled 2012 kernel via the EFI boot stub - a bootloader that supports 2013 the EFI handover protocol must be used. 2014 2015 If unsure, say N. 2016 2017config EFI_FAKE_MEMMAP 2018 bool "Enable EFI fake memory map" 2019 depends on EFI 2020 help 2021 Saying Y here will enable "efi_fake_mem" boot option. By specifying 2022 this parameter, you can add arbitrary attribute to specific memory 2023 range by updating original (firmware provided) EFI memmap. This is 2024 useful for debugging of EFI memmap related feature, e.g., Address 2025 Range Mirroring feature. 2026 2027config EFI_MAX_FAKE_MEM 2028 int "maximum allowable number of ranges in efi_fake_mem boot option" 2029 depends on EFI_FAKE_MEMMAP 2030 range 1 128 2031 default 8 2032 help 2033 Maximum allowable number of ranges in efi_fake_mem boot option. 2034 Ranges can be set up to this value using comma-separated list. 2035 The default value is 8. 2036 2037config EFI_RUNTIME_MAP 2038 bool "Export EFI runtime maps to sysfs" if EXPERT 2039 depends on EFI 2040 default KEXEC_CORE 2041 help 2042 Export EFI runtime memory regions to /sys/firmware/efi/runtime-map. 2043 That memory map is required by the 2nd kernel to set up EFI virtual 2044 mappings after kexec, but can also be used for debugging purposes. 2045 2046 See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map. 2047 2048source "kernel/Kconfig.hz" 2049 2050config KEXEC 2051 bool "kexec system call" 2052 select KEXEC_CORE 2053 help 2054 kexec is a system call that implements the ability to shutdown your 2055 current kernel, and to start another kernel. It is like a reboot 2056 but it is independent of the system firmware. And like a reboot 2057 you can start any kernel with it, not just Linux. 2058 2059 The name comes from the similarity to the exec system call. 2060 2061 It is an ongoing process to be certain the hardware in a machine 2062 is properly shutdown, so do not be surprised if this code does not 2063 initially work for you. As of this writing the exact hardware 2064 interface is strongly in flux, so no good recommendation can be 2065 made. 2066 2067config KEXEC_FILE 2068 bool "kexec file based system call" 2069 select KEXEC_CORE 2070 select HAVE_IMA_KEXEC if IMA 2071 depends on X86_64 2072 depends on CRYPTO=y 2073 depends on CRYPTO_SHA256=y 2074 help 2075 This is new version of kexec system call. This system call is 2076 file based and takes file descriptors as system call argument 2077 for kernel and initramfs as opposed to list of segments as 2078 accepted by previous system call. 2079 2080config ARCH_HAS_KEXEC_PURGATORY 2081 def_bool KEXEC_FILE 2082 2083config KEXEC_SIG 2084 bool "Verify kernel signature during kexec_file_load() syscall" 2085 depends on KEXEC_FILE 2086 help 2087 2088 This option makes the kexec_file_load() syscall check for a valid 2089 signature of the kernel image. The image can still be loaded without 2090 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2091 there's a signature that we can check, then it must be valid. 2092 2093 In addition to this option, you need to enable signature 2094 verification for the corresponding kernel image type being 2095 loaded in order for this to work. 2096 2097config KEXEC_SIG_FORCE 2098 bool "Require a valid signature in kexec_file_load() syscall" 2099 depends on KEXEC_SIG 2100 help 2101 This option makes kernel signature verification mandatory for 2102 the kexec_file_load() syscall. 2103 2104config KEXEC_BZIMAGE_VERIFY_SIG 2105 bool "Enable bzImage signature verification support" 2106 depends on KEXEC_SIG 2107 depends on SIGNED_PE_FILE_VERIFICATION 2108 select SYSTEM_TRUSTED_KEYRING 2109 help 2110 Enable bzImage signature verification support. 2111 2112config CRASH_DUMP 2113 bool "kernel crash dumps" 2114 depends on X86_64 || (X86_32 && HIGHMEM) 2115 help 2116 Generate crash dump after being started by kexec. 2117 This should be normally only set in special crash dump kernels 2118 which are loaded in the main kernel with kexec-tools into 2119 a specially reserved region and then later executed after 2120 a crash by kdump/kexec. The crash dump kernel must be compiled 2121 to a memory address not used by the main kernel or BIOS using 2122 PHYSICAL_START, or it must be built as a relocatable image 2123 (CONFIG_RELOCATABLE=y). 2124 For more details see Documentation/admin-guide/kdump/kdump.rst 2125 2126config KEXEC_JUMP 2127 bool "kexec jump" 2128 depends on KEXEC && HIBERNATION 2129 help 2130 Jump between original kernel and kexeced kernel and invoke 2131 code in physical address mode via KEXEC 2132 2133config PHYSICAL_START 2134 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2135 default "0x1000000" 2136 help 2137 This gives the physical address where the kernel is loaded. 2138 2139 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2140 bzImage will decompress itself to above physical address and 2141 run from there. Otherwise, bzImage will run from the address where 2142 it has been loaded by the boot loader and will ignore above physical 2143 address. 2144 2145 In normal kdump cases one does not have to set/change this option 2146 as now bzImage can be compiled as a completely relocatable image 2147 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2148 address. This option is mainly useful for the folks who don't want 2149 to use a bzImage for capturing the crash dump and want to use a 2150 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2151 to be specifically compiled to run from a specific memory area 2152 (normally a reserved region) and this option comes handy. 2153 2154 So if you are using bzImage for capturing the crash dump, 2155 leave the value here unchanged to 0x1000000 and set 2156 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2157 for capturing the crash dump change this value to start of 2158 the reserved region. In other words, it can be set based on 2159 the "X" value as specified in the "crashkernel=YM@XM" 2160 command line boot parameter passed to the panic-ed 2161 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2162 for more details about crash dumps. 2163 2164 Usage of bzImage for capturing the crash dump is recommended as 2165 one does not have to build two kernels. Same kernel can be used 2166 as production kernel and capture kernel. Above option should have 2167 gone away after relocatable bzImage support is introduced. But it 2168 is present because there are users out there who continue to use 2169 vmlinux for dump capture. This option should go away down the 2170 line. 2171 2172 Don't change this unless you know what you are doing. 2173 2174config RELOCATABLE 2175 bool "Build a relocatable kernel" 2176 default y 2177 help 2178 This builds a kernel image that retains relocation information 2179 so it can be loaded someplace besides the default 1MB. 2180 The relocations tend to make the kernel binary about 10% larger, 2181 but are discarded at runtime. 2182 2183 One use is for the kexec on panic case where the recovery kernel 2184 must live at a different physical address than the primary 2185 kernel. 2186 2187 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2188 it has been loaded at and the compile time physical address 2189 (CONFIG_PHYSICAL_START) is used as the minimum location. 2190 2191config RANDOMIZE_BASE 2192 bool "Randomize the address of the kernel image (KASLR)" 2193 depends on RELOCATABLE 2194 default y 2195 help 2196 In support of Kernel Address Space Layout Randomization (KASLR), 2197 this randomizes the physical address at which the kernel image 2198 is decompressed and the virtual address where the kernel 2199 image is mapped, as a security feature that deters exploit 2200 attempts relying on knowledge of the location of kernel 2201 code internals. 2202 2203 On 64-bit, the kernel physical and virtual addresses are 2204 randomized separately. The physical address will be anywhere 2205 between 16MB and the top of physical memory (up to 64TB). The 2206 virtual address will be randomized from 16MB up to 1GB (9 bits 2207 of entropy). Note that this also reduces the memory space 2208 available to kernel modules from 1.5GB to 1GB. 2209 2210 On 32-bit, the kernel physical and virtual addresses are 2211 randomized together. They will be randomized from 16MB up to 2212 512MB (8 bits of entropy). 2213 2214 Entropy is generated using the RDRAND instruction if it is 2215 supported. If RDTSC is supported, its value is mixed into 2216 the entropy pool as well. If neither RDRAND nor RDTSC are 2217 supported, then entropy is read from the i8254 timer. The 2218 usable entropy is limited by the kernel being built using 2219 2GB addressing, and that PHYSICAL_ALIGN must be at a 2220 minimum of 2MB. As a result, only 10 bits of entropy are 2221 theoretically possible, but the implementations are further 2222 limited due to memory layouts. 2223 2224 If unsure, say Y. 2225 2226# Relocation on x86 needs some additional build support 2227config X86_NEED_RELOCS 2228 def_bool y 2229 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2230 2231config PHYSICAL_ALIGN 2232 hex "Alignment value to which kernel should be aligned" 2233 default "0x200000" 2234 range 0x2000 0x1000000 if X86_32 2235 range 0x200000 0x1000000 if X86_64 2236 help 2237 This value puts the alignment restrictions on physical address 2238 where kernel is loaded and run from. Kernel is compiled for an 2239 address which meets above alignment restriction. 2240 2241 If bootloader loads the kernel at a non-aligned address and 2242 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2243 address aligned to above value and run from there. 2244 2245 If bootloader loads the kernel at a non-aligned address and 2246 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2247 load address and decompress itself to the address it has been 2248 compiled for and run from there. The address for which kernel is 2249 compiled already meets above alignment restrictions. Hence the 2250 end result is that kernel runs from a physical address meeting 2251 above alignment restrictions. 2252 2253 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2254 this value must be a multiple of 0x200000. 2255 2256 Don't change this unless you know what you are doing. 2257 2258config DYNAMIC_MEMORY_LAYOUT 2259 bool 2260 help 2261 This option makes base addresses of vmalloc and vmemmap as well as 2262 __PAGE_OFFSET movable during boot. 2263 2264config RANDOMIZE_MEMORY 2265 bool "Randomize the kernel memory sections" 2266 depends on X86_64 2267 depends on RANDOMIZE_BASE 2268 select DYNAMIC_MEMORY_LAYOUT 2269 default RANDOMIZE_BASE 2270 help 2271 Randomizes the base virtual address of kernel memory sections 2272 (physical memory mapping, vmalloc & vmemmap). This security feature 2273 makes exploits relying on predictable memory locations less reliable. 2274 2275 The order of allocations remains unchanged. Entropy is generated in 2276 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2277 configuration have in average 30,000 different possible virtual 2278 addresses for each memory section. 2279 2280 If unsure, say Y. 2281 2282config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2283 hex "Physical memory mapping padding" if EXPERT 2284 depends on RANDOMIZE_MEMORY 2285 default "0xa" if MEMORY_HOTPLUG 2286 default "0x0" 2287 range 0x1 0x40 if MEMORY_HOTPLUG 2288 range 0x0 0x40 2289 help 2290 Define the padding in terabytes added to the existing physical 2291 memory size during kernel memory randomization. It is useful 2292 for memory hotplug support but reduces the entropy available for 2293 address randomization. 2294 2295 If unsure, leave at the default value. 2296 2297config HOTPLUG_CPU 2298 def_bool y 2299 depends on SMP 2300 2301config BOOTPARAM_HOTPLUG_CPU0 2302 bool "Set default setting of cpu0_hotpluggable" 2303 depends on HOTPLUG_CPU 2304 help 2305 Set whether default state of cpu0_hotpluggable is on or off. 2306 2307 Say Y here to enable CPU0 hotplug by default. If this switch 2308 is turned on, there is no need to give cpu0_hotplug kernel 2309 parameter and the CPU0 hotplug feature is enabled by default. 2310 2311 Please note: there are two known CPU0 dependencies if you want 2312 to enable the CPU0 hotplug feature either by this switch or by 2313 cpu0_hotplug kernel parameter. 2314 2315 First, resume from hibernate or suspend always starts from CPU0. 2316 So hibernate and suspend are prevented if CPU0 is offline. 2317 2318 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2319 offline if any interrupt can not migrate out of CPU0. There may 2320 be other CPU0 dependencies. 2321 2322 Please make sure the dependencies are under your control before 2323 you enable this feature. 2324 2325 Say N if you don't want to enable CPU0 hotplug feature by default. 2326 You still can enable the CPU0 hotplug feature at boot by kernel 2327 parameter cpu0_hotplug. 2328 2329config DEBUG_HOTPLUG_CPU0 2330 def_bool n 2331 prompt "Debug CPU0 hotplug" 2332 depends on HOTPLUG_CPU 2333 help 2334 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2335 soon as possible and boots up userspace with CPU0 offlined. User 2336 can online CPU0 back after boot time. 2337 2338 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2339 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2340 compilation or giving cpu0_hotplug kernel parameter at boot. 2341 2342 If unsure, say N. 2343 2344config COMPAT_VDSO 2345 def_bool n 2346 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2347 depends on COMPAT_32 2348 help 2349 Certain buggy versions of glibc will crash if they are 2350 presented with a 32-bit vDSO that is not mapped at the address 2351 indicated in its segment table. 2352 2353 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2354 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2355 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2356 the only released version with the bug, but OpenSUSE 9 2357 contains a buggy "glibc 2.3.2". 2358 2359 The symptom of the bug is that everything crashes on startup, saying: 2360 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2361 2362 Saying Y here changes the default value of the vdso32 boot 2363 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2364 This works around the glibc bug but hurts performance. 2365 2366 If unsure, say N: if you are compiling your own kernel, you 2367 are unlikely to be using a buggy version of glibc. 2368 2369choice 2370 prompt "vsyscall table for legacy applications" 2371 depends on X86_64 2372 default LEGACY_VSYSCALL_XONLY 2373 help 2374 Legacy user code that does not know how to find the vDSO expects 2375 to be able to issue three syscalls by calling fixed addresses in 2376 kernel space. Since this location is not randomized with ASLR, 2377 it can be used to assist security vulnerability exploitation. 2378 2379 This setting can be changed at boot time via the kernel command 2380 line parameter vsyscall=[emulate|xonly|none]. Emulate mode 2381 is deprecated and can only be enabled using the kernel command 2382 line. 2383 2384 On a system with recent enough glibc (2.14 or newer) and no 2385 static binaries, you can say None without a performance penalty 2386 to improve security. 2387 2388 If unsure, select "Emulate execution only". 2389 2390 config LEGACY_VSYSCALL_XONLY 2391 bool "Emulate execution only" 2392 help 2393 The kernel traps and emulates calls into the fixed vsyscall 2394 address mapping and does not allow reads. This 2395 configuration is recommended when userspace might use the 2396 legacy vsyscall area but support for legacy binary 2397 instrumentation of legacy code is not needed. It mitigates 2398 certain uses of the vsyscall area as an ASLR-bypassing 2399 buffer. 2400 2401 config LEGACY_VSYSCALL_NONE 2402 bool "None" 2403 help 2404 There will be no vsyscall mapping at all. This will 2405 eliminate any risk of ASLR bypass due to the vsyscall 2406 fixed address mapping. Attempts to use the vsyscalls 2407 will be reported to dmesg, so that either old or 2408 malicious userspace programs can be identified. 2409 2410endchoice 2411 2412config CMDLINE_BOOL 2413 bool "Built-in kernel command line" 2414 help 2415 Allow for specifying boot arguments to the kernel at 2416 build time. On some systems (e.g. embedded ones), it is 2417 necessary or convenient to provide some or all of the 2418 kernel boot arguments with the kernel itself (that is, 2419 to not rely on the boot loader to provide them.) 2420 2421 To compile command line arguments into the kernel, 2422 set this option to 'Y', then fill in the 2423 boot arguments in CONFIG_CMDLINE. 2424 2425 Systems with fully functional boot loaders (i.e. non-embedded) 2426 should leave this option set to 'N'. 2427 2428config CMDLINE 2429 string "Built-in kernel command string" 2430 depends on CMDLINE_BOOL 2431 default "" 2432 help 2433 Enter arguments here that should be compiled into the kernel 2434 image and used at boot time. If the boot loader provides a 2435 command line at boot time, it is appended to this string to 2436 form the full kernel command line, when the system boots. 2437 2438 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2439 change this behavior. 2440 2441 In most cases, the command line (whether built-in or provided 2442 by the boot loader) should specify the device for the root 2443 file system. 2444 2445config CMDLINE_OVERRIDE 2446 bool "Built-in command line overrides boot loader arguments" 2447 depends on CMDLINE_BOOL && CMDLINE != "" 2448 help 2449 Set this option to 'Y' to have the kernel ignore the boot loader 2450 command line, and use ONLY the built-in command line. 2451 2452 This is used to work around broken boot loaders. This should 2453 be set to 'N' under normal conditions. 2454 2455config MODIFY_LDT_SYSCALL 2456 bool "Enable the LDT (local descriptor table)" if EXPERT 2457 default y 2458 help 2459 Linux can allow user programs to install a per-process x86 2460 Local Descriptor Table (LDT) using the modify_ldt(2) system 2461 call. This is required to run 16-bit or segmented code such as 2462 DOSEMU or some Wine programs. It is also used by some very old 2463 threading libraries. 2464 2465 Enabling this feature adds a small amount of overhead to 2466 context switches and increases the low-level kernel attack 2467 surface. Disabling it removes the modify_ldt(2) system call. 2468 2469 Saying 'N' here may make sense for embedded or server kernels. 2470 2471config STRICT_SIGALTSTACK_SIZE 2472 bool "Enforce strict size checking for sigaltstack" 2473 depends on DYNAMIC_SIGFRAME 2474 help 2475 For historical reasons MINSIGSTKSZ is a constant which became 2476 already too small with AVX512 support. Add a mechanism to 2477 enforce strict checking of the sigaltstack size against the 2478 real size of the FPU frame. This option enables the check 2479 by default. It can also be controlled via the kernel command 2480 line option 'strict_sas_size' independent of this config 2481 switch. Enabling it might break existing applications which 2482 allocate a too small sigaltstack but 'work' because they 2483 never get a signal delivered. 2484 2485 Say 'N' unless you want to really enforce this check. 2486 2487source "kernel/livepatch/Kconfig" 2488 2489endmenu 2490 2491config CC_HAS_SLS 2492 def_bool $(cc-option,-mharden-sls=all) 2493 2494config CC_HAS_RETURN_THUNK 2495 def_bool $(cc-option,-mfunction-return=thunk-extern) 2496 2497config CC_HAS_ENTRY_PADDING 2498 def_bool $(cc-option,-fpatchable-function-entry=16,16) 2499 2500config FUNCTION_PADDING_CFI 2501 int 2502 default 59 if FUNCTION_ALIGNMENT_64B 2503 default 27 if FUNCTION_ALIGNMENT_32B 2504 default 11 if FUNCTION_ALIGNMENT_16B 2505 default 3 if FUNCTION_ALIGNMENT_8B 2506 default 0 2507 2508# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG 2509# except Kconfig can't do arithmetic :/ 2510config FUNCTION_PADDING_BYTES 2511 int 2512 default FUNCTION_PADDING_CFI if CFI_CLANG 2513 default FUNCTION_ALIGNMENT 2514 2515config CALL_PADDING 2516 def_bool n 2517 depends on CC_HAS_ENTRY_PADDING && OBJTOOL 2518 select FUNCTION_ALIGNMENT_16B 2519 2520config FINEIBT 2521 def_bool y 2522 depends on X86_KERNEL_IBT && CFI_CLANG && RETPOLINE 2523 select CALL_PADDING 2524 2525config HAVE_CALL_THUNKS 2526 def_bool y 2527 depends on CC_HAS_ENTRY_PADDING && RETHUNK && OBJTOOL 2528 2529config CALL_THUNKS 2530 def_bool n 2531 select CALL_PADDING 2532 2533config PREFIX_SYMBOLS 2534 def_bool y 2535 depends on CALL_PADDING && !CFI_CLANG 2536 2537menuconfig SPECULATION_MITIGATIONS 2538 bool "Mitigations for speculative execution vulnerabilities" 2539 default y 2540 help 2541 Say Y here to enable options which enable mitigations for 2542 speculative execution hardware vulnerabilities. 2543 2544 If you say N, all mitigations will be disabled. You really 2545 should know what you are doing to say so. 2546 2547if SPECULATION_MITIGATIONS 2548 2549config PAGE_TABLE_ISOLATION 2550 bool "Remove the kernel mapping in user mode" 2551 default y 2552 depends on (X86_64 || X86_PAE) 2553 help 2554 This feature reduces the number of hardware side channels by 2555 ensuring that the majority of kernel addresses are not mapped 2556 into userspace. 2557 2558 See Documentation/x86/pti.rst for more details. 2559 2560config RETPOLINE 2561 bool "Avoid speculative indirect branches in kernel" 2562 select OBJTOOL if HAVE_OBJTOOL 2563 default y 2564 help 2565 Compile kernel with the retpoline compiler options to guard against 2566 kernel-to-user data leaks by avoiding speculative indirect 2567 branches. Requires a compiler with -mindirect-branch=thunk-extern 2568 support for full protection. The kernel may run slower. 2569 2570config RETHUNK 2571 bool "Enable return-thunks" 2572 depends on RETPOLINE && CC_HAS_RETURN_THUNK 2573 select OBJTOOL if HAVE_OBJTOOL 2574 default y if X86_64 2575 help 2576 Compile the kernel with the return-thunks compiler option to guard 2577 against kernel-to-user data leaks by avoiding return speculation. 2578 Requires a compiler with -mfunction-return=thunk-extern 2579 support for full protection. The kernel may run slower. 2580 2581config CPU_UNRET_ENTRY 2582 bool "Enable UNRET on kernel entry" 2583 depends on CPU_SUP_AMD && RETHUNK && X86_64 2584 default y 2585 help 2586 Compile the kernel with support for the retbleed=unret mitigation. 2587 2588config CALL_DEPTH_TRACKING 2589 bool "Mitigate RSB underflow with call depth tracking" 2590 depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS 2591 select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 2592 select CALL_THUNKS 2593 default y 2594 help 2595 Compile the kernel with call depth tracking to mitigate the Intel 2596 SKL Return-Speculation-Buffer (RSB) underflow issue. The 2597 mitigation is off by default and needs to be enabled on the 2598 kernel command line via the retbleed=stuff option. For 2599 non-affected systems the overhead of this option is marginal as 2600 the call depth tracking is using run-time generated call thunks 2601 in a compiler generated padding area and call patching. This 2602 increases text size by ~5%. For non affected systems this space 2603 is unused. On affected SKL systems this results in a significant 2604 performance gain over the IBRS mitigation. 2605 2606config CALL_THUNKS_DEBUG 2607 bool "Enable call thunks and call depth tracking debugging" 2608 depends on CALL_DEPTH_TRACKING 2609 select FUNCTION_ALIGNMENT_32B 2610 default n 2611 help 2612 Enable call/ret counters for imbalance detection and build in 2613 a noisy dmesg about callthunks generation and call patching for 2614 trouble shooting. The debug prints need to be enabled on the 2615 kernel command line with 'debug-callthunks'. 2616 Only enable this, when you are debugging call thunks as this 2617 creates a noticable runtime overhead. If unsure say N. 2618 2619config CPU_IBPB_ENTRY 2620 bool "Enable IBPB on kernel entry" 2621 depends on CPU_SUP_AMD && X86_64 2622 default y 2623 help 2624 Compile the kernel with support for the retbleed=ibpb mitigation. 2625 2626config CPU_IBRS_ENTRY 2627 bool "Enable IBRS on kernel entry" 2628 depends on CPU_SUP_INTEL && X86_64 2629 default y 2630 help 2631 Compile the kernel with support for the spectre_v2=ibrs mitigation. 2632 This mitigates both spectre_v2 and retbleed at great cost to 2633 performance. 2634 2635config SLS 2636 bool "Mitigate Straight-Line-Speculation" 2637 depends on CC_HAS_SLS && X86_64 2638 select OBJTOOL if HAVE_OBJTOOL 2639 default n 2640 help 2641 Compile the kernel with straight-line-speculation options to guard 2642 against straight line speculation. The kernel image might be slightly 2643 larger. 2644 2645endif 2646 2647config ARCH_HAS_ADD_PAGES 2648 def_bool y 2649 depends on ARCH_ENABLE_MEMORY_HOTPLUG 2650 2651config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 2652 def_bool y 2653 2654menu "Power management and ACPI options" 2655 2656config ARCH_HIBERNATION_HEADER 2657 def_bool y 2658 depends on HIBERNATION 2659 2660source "kernel/power/Kconfig" 2661 2662source "drivers/acpi/Kconfig" 2663 2664config X86_APM_BOOT 2665 def_bool y 2666 depends on APM 2667 2668menuconfig APM 2669 tristate "APM (Advanced Power Management) BIOS support" 2670 depends on X86_32 && PM_SLEEP 2671 help 2672 APM is a BIOS specification for saving power using several different 2673 techniques. This is mostly useful for battery powered laptops with 2674 APM compliant BIOSes. If you say Y here, the system time will be 2675 reset after a RESUME operation, the /proc/apm device will provide 2676 battery status information, and user-space programs will receive 2677 notification of APM "events" (e.g. battery status change). 2678 2679 If you select "Y" here, you can disable actual use of the APM 2680 BIOS by passing the "apm=off" option to the kernel at boot time. 2681 2682 Note that the APM support is almost completely disabled for 2683 machines with more than one CPU. 2684 2685 In order to use APM, you will need supporting software. For location 2686 and more information, read <file:Documentation/power/apm-acpi.rst> 2687 and the Battery Powered Linux mini-HOWTO, available from 2688 <http://www.tldp.org/docs.html#howto>. 2689 2690 This driver does not spin down disk drives (see the hdparm(8) 2691 manpage ("man 8 hdparm") for that), and it doesn't turn off 2692 VESA-compliant "green" monitors. 2693 2694 This driver does not support the TI 4000M TravelMate and the ACER 2695 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2696 desktop machines also don't have compliant BIOSes, and this driver 2697 may cause those machines to panic during the boot phase. 2698 2699 Generally, if you don't have a battery in your machine, there isn't 2700 much point in using this driver and you should say N. If you get 2701 random kernel OOPSes or reboots that don't seem to be related to 2702 anything, try disabling/enabling this option (or disabling/enabling 2703 APM in your BIOS). 2704 2705 Some other things you should try when experiencing seemingly random, 2706 "weird" problems: 2707 2708 1) make sure that you have enough swap space and that it is 2709 enabled. 2710 2) pass the "idle=poll" option to the kernel 2711 3) switch on floating point emulation in the kernel and pass 2712 the "no387" option to the kernel 2713 4) pass the "floppy=nodma" option to the kernel 2714 5) pass the "mem=4M" option to the kernel (thereby disabling 2715 all but the first 4 MB of RAM) 2716 6) make sure that the CPU is not over clocked. 2717 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2718 8) disable the cache from your BIOS settings 2719 9) install a fan for the video card or exchange video RAM 2720 10) install a better fan for the CPU 2721 11) exchange RAM chips 2722 12) exchange the motherboard. 2723 2724 To compile this driver as a module, choose M here: the 2725 module will be called apm. 2726 2727if APM 2728 2729config APM_IGNORE_USER_SUSPEND 2730 bool "Ignore USER SUSPEND" 2731 help 2732 This option will ignore USER SUSPEND requests. On machines with a 2733 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2734 series notebooks, it is necessary to say Y because of a BIOS bug. 2735 2736config APM_DO_ENABLE 2737 bool "Enable PM at boot time" 2738 help 2739 Enable APM features at boot time. From page 36 of the APM BIOS 2740 specification: "When disabled, the APM BIOS does not automatically 2741 power manage devices, enter the Standby State, enter the Suspend 2742 State, or take power saving steps in response to CPU Idle calls." 2743 This driver will make CPU Idle calls when Linux is idle (unless this 2744 feature is turned off -- see "Do CPU IDLE calls", below). This 2745 should always save battery power, but more complicated APM features 2746 will be dependent on your BIOS implementation. You may need to turn 2747 this option off if your computer hangs at boot time when using APM 2748 support, or if it beeps continuously instead of suspending. Turn 2749 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2750 T400CDT. This is off by default since most machines do fine without 2751 this feature. 2752 2753config APM_CPU_IDLE 2754 depends on CPU_IDLE 2755 bool "Make CPU Idle calls when idle" 2756 help 2757 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2758 On some machines, this can activate improved power savings, such as 2759 a slowed CPU clock rate, when the machine is idle. These idle calls 2760 are made after the idle loop has run for some length of time (e.g., 2761 333 mS). On some machines, this will cause a hang at boot time or 2762 whenever the CPU becomes idle. (On machines with more than one CPU, 2763 this option does nothing.) 2764 2765config APM_DISPLAY_BLANK 2766 bool "Enable console blanking using APM" 2767 help 2768 Enable console blanking using the APM. Some laptops can use this to 2769 turn off the LCD backlight when the screen blanker of the Linux 2770 virtual console blanks the screen. Note that this is only used by 2771 the virtual console screen blanker, and won't turn off the backlight 2772 when using the X Window system. This also doesn't have anything to 2773 do with your VESA-compliant power-saving monitor. Further, this 2774 option doesn't work for all laptops -- it might not turn off your 2775 backlight at all, or it might print a lot of errors to the console, 2776 especially if you are using gpm. 2777 2778config APM_ALLOW_INTS 2779 bool "Allow interrupts during APM BIOS calls" 2780 help 2781 Normally we disable external interrupts while we are making calls to 2782 the APM BIOS as a measure to lessen the effects of a badly behaving 2783 BIOS implementation. The BIOS should reenable interrupts if it 2784 needs to. Unfortunately, some BIOSes do not -- especially those in 2785 many of the newer IBM Thinkpads. If you experience hangs when you 2786 suspend, try setting this to Y. Otherwise, say N. 2787 2788endif # APM 2789 2790source "drivers/cpufreq/Kconfig" 2791 2792source "drivers/cpuidle/Kconfig" 2793 2794source "drivers/idle/Kconfig" 2795 2796endmenu 2797 2798menu "Bus options (PCI etc.)" 2799 2800choice 2801 prompt "PCI access mode" 2802 depends on X86_32 && PCI 2803 default PCI_GOANY 2804 help 2805 On PCI systems, the BIOS can be used to detect the PCI devices and 2806 determine their configuration. However, some old PCI motherboards 2807 have BIOS bugs and may crash if this is done. Also, some embedded 2808 PCI-based systems don't have any BIOS at all. Linux can also try to 2809 detect the PCI hardware directly without using the BIOS. 2810 2811 With this option, you can specify how Linux should detect the 2812 PCI devices. If you choose "BIOS", the BIOS will be used, 2813 if you choose "Direct", the BIOS won't be used, and if you 2814 choose "MMConfig", then PCI Express MMCONFIG will be used. 2815 If you choose "Any", the kernel will try MMCONFIG, then the 2816 direct access method and falls back to the BIOS if that doesn't 2817 work. If unsure, go with the default, which is "Any". 2818 2819config PCI_GOBIOS 2820 bool "BIOS" 2821 2822config PCI_GOMMCONFIG 2823 bool "MMConfig" 2824 2825config PCI_GODIRECT 2826 bool "Direct" 2827 2828config PCI_GOOLPC 2829 bool "OLPC XO-1" 2830 depends on OLPC 2831 2832config PCI_GOANY 2833 bool "Any" 2834 2835endchoice 2836 2837config PCI_BIOS 2838 def_bool y 2839 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2840 2841# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2842config PCI_DIRECT 2843 def_bool y 2844 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2845 2846config PCI_MMCONFIG 2847 bool "Support mmconfig PCI config space access" if X86_64 2848 default y 2849 depends on PCI && (ACPI || JAILHOUSE_GUEST) 2850 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2851 2852config PCI_OLPC 2853 def_bool y 2854 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2855 2856config PCI_XEN 2857 def_bool y 2858 depends on PCI && XEN 2859 2860config MMCONF_FAM10H 2861 def_bool y 2862 depends on X86_64 && PCI_MMCONFIG && ACPI 2863 2864config PCI_CNB20LE_QUIRK 2865 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2866 depends on PCI 2867 help 2868 Read the PCI windows out of the CNB20LE host bridge. This allows 2869 PCI hotplug to work on systems with the CNB20LE chipset which do 2870 not have ACPI. 2871 2872 There's no public spec for this chipset, and this functionality 2873 is known to be incomplete. 2874 2875 You should say N unless you know you need this. 2876 2877config ISA_BUS 2878 bool "ISA bus support on modern systems" if EXPERT 2879 help 2880 Expose ISA bus device drivers and options available for selection and 2881 configuration. Enable this option if your target machine has an ISA 2882 bus. ISA is an older system, displaced by PCI and newer bus 2883 architectures -- if your target machine is modern, it probably does 2884 not have an ISA bus. 2885 2886 If unsure, say N. 2887 2888# x86_64 have no ISA slots, but can have ISA-style DMA. 2889config ISA_DMA_API 2890 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2891 default y 2892 help 2893 Enables ISA-style DMA support for devices requiring such controllers. 2894 If unsure, say Y. 2895 2896if X86_32 2897 2898config ISA 2899 bool "ISA support" 2900 help 2901 Find out whether you have ISA slots on your motherboard. ISA is the 2902 name of a bus system, i.e. the way the CPU talks to the other stuff 2903 inside your box. Other bus systems are PCI, EISA, MicroChannel 2904 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2905 newer boards don't support it. If you have ISA, say Y, otherwise N. 2906 2907config SCx200 2908 tristate "NatSemi SCx200 support" 2909 help 2910 This provides basic support for National Semiconductor's 2911 (now AMD's) Geode processors. The driver probes for the 2912 PCI-IDs of several on-chip devices, so its a good dependency 2913 for other scx200_* drivers. 2914 2915 If compiled as a module, the driver is named scx200. 2916 2917config SCx200HR_TIMER 2918 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2919 depends on SCx200 2920 default y 2921 help 2922 This driver provides a clocksource built upon the on-chip 2923 27MHz high-resolution timer. Its also a workaround for 2924 NSC Geode SC-1100's buggy TSC, which loses time when the 2925 processor goes idle (as is done by the scheduler). The 2926 other workaround is idle=poll boot option. 2927 2928config OLPC 2929 bool "One Laptop Per Child support" 2930 depends on !X86_PAE 2931 select GPIOLIB 2932 select OF 2933 select OF_PROMTREE 2934 select IRQ_DOMAIN 2935 select OLPC_EC 2936 help 2937 Add support for detecting the unique features of the OLPC 2938 XO hardware. 2939 2940config OLPC_XO1_PM 2941 bool "OLPC XO-1 Power Management" 2942 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2943 help 2944 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2945 2946config OLPC_XO1_RTC 2947 bool "OLPC XO-1 Real Time Clock" 2948 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2949 help 2950 Add support for the XO-1 real time clock, which can be used as a 2951 programmable wakeup source. 2952 2953config OLPC_XO1_SCI 2954 bool "OLPC XO-1 SCI extras" 2955 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2956 depends on INPUT=y 2957 select POWER_SUPPLY 2958 help 2959 Add support for SCI-based features of the OLPC XO-1 laptop: 2960 - EC-driven system wakeups 2961 - Power button 2962 - Ebook switch 2963 - Lid switch 2964 - AC adapter status updates 2965 - Battery status updates 2966 2967config OLPC_XO15_SCI 2968 bool "OLPC XO-1.5 SCI extras" 2969 depends on OLPC && ACPI 2970 select POWER_SUPPLY 2971 help 2972 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2973 - EC-driven system wakeups 2974 - AC adapter status updates 2975 - Battery status updates 2976 2977config ALIX 2978 bool "PCEngines ALIX System Support (LED setup)" 2979 select GPIOLIB 2980 help 2981 This option enables system support for the PCEngines ALIX. 2982 At present this just sets up LEDs for GPIO control on 2983 ALIX2/3/6 boards. However, other system specific setup should 2984 get added here. 2985 2986 Note: You must still enable the drivers for GPIO and LED support 2987 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2988 2989 Note: You have to set alix.force=1 for boards with Award BIOS. 2990 2991config NET5501 2992 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2993 select GPIOLIB 2994 help 2995 This option enables system support for the Soekris Engineering net5501. 2996 2997config GEOS 2998 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2999 select GPIOLIB 3000 depends on DMI 3001 help 3002 This option enables system support for the Traverse Technologies GEOS. 3003 3004config TS5500 3005 bool "Technologic Systems TS-5500 platform support" 3006 depends on MELAN 3007 select CHECK_SIGNATURE 3008 select NEW_LEDS 3009 select LEDS_CLASS 3010 help 3011 This option enables system support for the Technologic Systems TS-5500. 3012 3013endif # X86_32 3014 3015config AMD_NB 3016 def_bool y 3017 depends on CPU_SUP_AMD && PCI 3018 3019endmenu 3020 3021menu "Binary Emulations" 3022 3023config IA32_EMULATION 3024 bool "IA32 Emulation" 3025 depends on X86_64 3026 select ARCH_WANT_OLD_COMPAT_IPC 3027 select BINFMT_ELF 3028 select COMPAT_OLD_SIGACTION 3029 help 3030 Include code to run legacy 32-bit programs under a 3031 64-bit kernel. You should likely turn this on, unless you're 3032 100% sure that you don't have any 32-bit programs left. 3033 3034config X86_X32_ABI 3035 bool "x32 ABI for 64-bit mode" 3036 depends on X86_64 3037 # llvm-objcopy does not convert x86_64 .note.gnu.property or 3038 # compressed debug sections to x86_x32 properly: 3039 # https://github.com/ClangBuiltLinux/linux/issues/514 3040 # https://github.com/ClangBuiltLinux/linux/issues/1141 3041 depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm) 3042 help 3043 Include code to run binaries for the x32 native 32-bit ABI 3044 for 64-bit processors. An x32 process gets access to the 3045 full 64-bit register file and wide data path while leaving 3046 pointers at 32 bits for smaller memory footprint. 3047 3048config COMPAT_32 3049 def_bool y 3050 depends on IA32_EMULATION || X86_32 3051 select HAVE_UID16 3052 select OLD_SIGSUSPEND3 3053 3054config COMPAT 3055 def_bool y 3056 depends on IA32_EMULATION || X86_X32_ABI 3057 3058config COMPAT_FOR_U64_ALIGNMENT 3059 def_bool y 3060 depends on COMPAT 3061 3062endmenu 3063 3064config HAVE_ATOMIC_IOMAP 3065 def_bool y 3066 depends on X86_32 3067 3068source "arch/x86/kvm/Kconfig" 3069 3070source "arch/x86/Kconfig.assembler" 3071