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_PXX_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_OBJTOOL_NOP_MCOUNT if HAVE_OBJTOOL_MCOUNT 201 select HAVE_BUILDTIME_MCOUNT_SORT 202 select HAVE_DEBUG_KMEMLEAK 203 select HAVE_DMA_CONTIGUOUS 204 select HAVE_DYNAMIC_FTRACE 205 select HAVE_DYNAMIC_FTRACE_WITH_REGS 206 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 207 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 208 select HAVE_SAMPLE_FTRACE_DIRECT if X86_64 209 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64 210 select HAVE_EBPF_JIT 211 select HAVE_EFFICIENT_UNALIGNED_ACCESS 212 select HAVE_EISA 213 select HAVE_EXIT_THREAD 214 select HAVE_FAST_GUP 215 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 216 select HAVE_FTRACE_MCOUNT_RECORD 217 select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) 218 select HAVE_FUNCTION_TRACER 219 select HAVE_GCC_PLUGINS 220 select HAVE_HW_BREAKPOINT 221 select HAVE_IOREMAP_PROT 222 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 223 select HAVE_IRQ_TIME_ACCOUNTING 224 select HAVE_JUMP_LABEL_HACK if HAVE_OBJTOOL 225 select HAVE_KERNEL_BZIP2 226 select HAVE_KERNEL_GZIP 227 select HAVE_KERNEL_LZ4 228 select HAVE_KERNEL_LZMA 229 select HAVE_KERNEL_LZO 230 select HAVE_KERNEL_XZ 231 select HAVE_KERNEL_ZSTD 232 select HAVE_KPROBES 233 select HAVE_KPROBES_ON_FTRACE 234 select HAVE_FUNCTION_ERROR_INJECTION 235 select HAVE_KRETPROBES 236 select HAVE_RETHOOK 237 select HAVE_KVM 238 select HAVE_LIVEPATCH if X86_64 239 select HAVE_MIXED_BREAKPOINTS_REGS 240 select HAVE_MOD_ARCH_SPECIFIC 241 select HAVE_MOVE_PMD 242 select HAVE_MOVE_PUD 243 select HAVE_NOINSTR_HACK if HAVE_OBJTOOL 244 select HAVE_NMI 245 select HAVE_NOINSTR_VALIDATION if HAVE_OBJTOOL 246 select HAVE_OBJTOOL if X86_64 247 select HAVE_OPTPROBES 248 select HAVE_PCSPKR_PLATFORM 249 select HAVE_PERF_EVENTS 250 select HAVE_PERF_EVENTS_NMI 251 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 252 select HAVE_PCI 253 select HAVE_PERF_REGS 254 select HAVE_PERF_USER_STACK_DUMP 255 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 256 select MMU_GATHER_MERGE_VMAS 257 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 258 select HAVE_REGS_AND_STACK_ACCESS_API 259 select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC || STACK_VALIDATION 260 select HAVE_FUNCTION_ARG_ACCESS_API 261 select HAVE_SETUP_PER_CPU_AREA 262 select HAVE_SOFTIRQ_ON_OWN_STACK 263 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 264 select HAVE_STACK_VALIDATION if HAVE_OBJTOOL 265 select HAVE_STATIC_CALL 266 select HAVE_STATIC_CALL_INLINE if HAVE_OBJTOOL 267 select HAVE_PREEMPT_DYNAMIC_CALL 268 select HAVE_RSEQ 269 select HAVE_RUST if X86_64 270 select HAVE_SYSCALL_TRACEPOINTS 271 select HAVE_UACCESS_VALIDATION if HAVE_OBJTOOL 272 select HAVE_UNSTABLE_SCHED_CLOCK 273 select HAVE_USER_RETURN_NOTIFIER 274 select HAVE_GENERIC_VDSO 275 select HOTPLUG_SMT if SMP 276 select IRQ_FORCED_THREADING 277 select NEED_PER_CPU_EMBED_FIRST_CHUNK 278 select NEED_PER_CPU_PAGE_FIRST_CHUNK 279 select NEED_SG_DMA_LENGTH 280 select PCI_DOMAINS if PCI 281 select PCI_LOCKLESS_CONFIG if PCI 282 select PERF_EVENTS 283 select RTC_LIB 284 select RTC_MC146818_LIB 285 select SPARSE_IRQ 286 select SRCU 287 select SYSCTL_EXCEPTION_TRACE 288 select THREAD_INFO_IN_TASK 289 select TRACE_IRQFLAGS_SUPPORT 290 select TRACE_IRQFLAGS_NMI_SUPPORT 291 select USER_STACKTRACE_SUPPORT 292 select HAVE_ARCH_KCSAN if X86_64 293 select X86_FEATURE_NAMES if PROC_FS 294 select PROC_PID_ARCH_STATUS if PROC_FS 295 select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX 296 select FUNCTION_ALIGNMENT_16B if X86_64 || X86_ALIGNMENT_16 297 select FUNCTION_ALIGNMENT_4B 298 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 299 select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 300 301config INSTRUCTION_DECODER 302 def_bool y 303 depends on KPROBES || PERF_EVENTS || UPROBES 304 305config OUTPUT_FORMAT 306 string 307 default "elf32-i386" if X86_32 308 default "elf64-x86-64" if X86_64 309 310config LOCKDEP_SUPPORT 311 def_bool y 312 313config STACKTRACE_SUPPORT 314 def_bool y 315 316config MMU 317 def_bool y 318 319config ARCH_MMAP_RND_BITS_MIN 320 default 28 if 64BIT 321 default 8 322 323config ARCH_MMAP_RND_BITS_MAX 324 default 32 if 64BIT 325 default 16 326 327config ARCH_MMAP_RND_COMPAT_BITS_MIN 328 default 8 329 330config ARCH_MMAP_RND_COMPAT_BITS_MAX 331 default 16 332 333config SBUS 334 bool 335 336config GENERIC_ISA_DMA 337 def_bool y 338 depends on ISA_DMA_API 339 340config GENERIC_CSUM 341 bool 342 default y if KMSAN || KASAN 343 344config GENERIC_BUG 345 def_bool y 346 depends on BUG 347 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 348 349config GENERIC_BUG_RELATIVE_POINTERS 350 bool 351 352config ARCH_MAY_HAVE_PC_FDC 353 def_bool y 354 depends on ISA_DMA_API 355 356config GENERIC_CALIBRATE_DELAY 357 def_bool y 358 359config ARCH_HAS_CPU_RELAX 360 def_bool y 361 362config ARCH_HIBERNATION_POSSIBLE 363 def_bool y 364 365config ARCH_SUSPEND_POSSIBLE 366 def_bool y 367 368config AUDIT_ARCH 369 def_bool y if X86_64 370 371config KASAN_SHADOW_OFFSET 372 hex 373 depends on KASAN 374 default 0xdffffc0000000000 375 376config HAVE_INTEL_TXT 377 def_bool y 378 depends on INTEL_IOMMU && ACPI 379 380config X86_32_SMP 381 def_bool y 382 depends on X86_32 && SMP 383 384config X86_64_SMP 385 def_bool y 386 depends on X86_64 && SMP 387 388config ARCH_SUPPORTS_UPROBES 389 def_bool y 390 391config FIX_EARLYCON_MEM 392 def_bool y 393 394config DYNAMIC_PHYSICAL_MASK 395 bool 396 397config PGTABLE_LEVELS 398 int 399 default 5 if X86_5LEVEL 400 default 4 if X86_64 401 default 3 if X86_PAE 402 default 2 403 404config CC_HAS_SANE_STACKPROTECTOR 405 bool 406 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT 407 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) 408 help 409 We have to make sure stack protector is unconditionally disabled if 410 the compiler produces broken code or if it does not let us control 411 the segment on 32-bit kernels. 412 413menu "Processor type and features" 414 415config SMP 416 bool "Symmetric multi-processing support" 417 help 418 This enables support for systems with more than one CPU. If you have 419 a system with only one CPU, say N. If you have a system with more 420 than one CPU, say Y. 421 422 If you say N here, the kernel will run on uni- and multiprocessor 423 machines, but will use only one CPU of a multiprocessor machine. If 424 you say Y here, the kernel will run on many, but not all, 425 uniprocessor machines. On a uniprocessor machine, the kernel 426 will run faster if you say N here. 427 428 Note that if you say Y here and choose architecture "586" or 429 "Pentium" under "Processor family", the kernel will not work on 486 430 architectures. Similarly, multiprocessor kernels for the "PPro" 431 architecture may not work on all Pentium based boards. 432 433 People using multiprocessor machines who say Y here should also say 434 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 435 Management" code will be disabled if you say Y here. 436 437 See also <file:Documentation/x86/i386/IO-APIC.rst>, 438 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 439 <http://www.tldp.org/docs.html#howto>. 440 441 If you don't know what to do here, say N. 442 443config X86_FEATURE_NAMES 444 bool "Processor feature human-readable names" if EMBEDDED 445 default y 446 help 447 This option compiles in a table of x86 feature bits and corresponding 448 names. This is required to support /proc/cpuinfo and a few kernel 449 messages. You can disable this to save space, at the expense of 450 making those few kernel messages show numeric feature bits instead. 451 452 If in doubt, say Y. 453 454config X86_X2APIC 455 bool "Support x2apic" 456 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 457 help 458 This enables x2apic support on CPUs that have this feature. 459 460 This allows 32-bit apic IDs (so it can support very large systems), 461 and accesses the local apic via MSRs not via mmio. 462 463 Some Intel systems circa 2022 and later are locked into x2APIC mode 464 and can not fall back to the legacy APIC modes if SGX or TDX are 465 enabled in the BIOS. They will boot with very reduced functionality 466 without enabling this option. 467 468 If you don't know what to do here, say N. 469 470config X86_MPPARSE 471 bool "Enable MPS table" if ACPI 472 default y 473 depends on X86_LOCAL_APIC 474 help 475 For old smp systems that do not have proper acpi support. Newer systems 476 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 477 478config GOLDFISH 479 def_bool y 480 depends on X86_GOLDFISH 481 482config X86_CPU_RESCTRL 483 bool "x86 CPU resource control support" 484 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 485 select KERNFS 486 select PROC_CPU_RESCTRL if PROC_FS 487 help 488 Enable x86 CPU resource control support. 489 490 Provide support for the allocation and monitoring of system resources 491 usage by the CPU. 492 493 Intel calls this Intel Resource Director Technology 494 (Intel(R) RDT). More information about RDT can be found in the 495 Intel x86 Architecture Software Developer Manual. 496 497 AMD calls this AMD Platform Quality of Service (AMD QoS). 498 More information about AMD QoS can be found in the AMD64 Technology 499 Platform Quality of Service Extensions manual. 500 501 Say N if unsure. 502 503if X86_32 504config X86_BIGSMP 505 bool "Support for big SMP systems with more than 8 CPUs" 506 depends on SMP 507 help 508 This option is needed for the systems that have more than 8 CPUs. 509 510config X86_EXTENDED_PLATFORM 511 bool "Support for extended (non-PC) x86 platforms" 512 default y 513 help 514 If you disable this option then the kernel will only support 515 standard PC platforms. (which covers the vast majority of 516 systems out there.) 517 518 If you enable this option then you'll be able to select support 519 for the following (non-PC) 32 bit x86 platforms: 520 Goldfish (Android emulator) 521 AMD Elan 522 RDC R-321x SoC 523 SGI 320/540 (Visual Workstation) 524 STA2X11-based (e.g. Northville) 525 Moorestown MID devices 526 527 If you have one of these systems, or if you want to build a 528 generic distribution kernel, say Y here - otherwise say N. 529endif # X86_32 530 531if X86_64 532config X86_EXTENDED_PLATFORM 533 bool "Support for extended (non-PC) x86 platforms" 534 default y 535 help 536 If you disable this option then the kernel will only support 537 standard PC platforms. (which covers the vast majority of 538 systems out there.) 539 540 If you enable this option then you'll be able to select support 541 for the following (non-PC) 64 bit x86 platforms: 542 Numascale NumaChip 543 ScaleMP vSMP 544 SGI Ultraviolet 545 546 If you have one of these systems, or if you want to build a 547 generic distribution kernel, say Y here - otherwise say N. 548endif # X86_64 549# This is an alphabetically sorted list of 64 bit extended platforms 550# Please maintain the alphabetic order if and when there are additions 551config X86_NUMACHIP 552 bool "Numascale NumaChip" 553 depends on X86_64 554 depends on X86_EXTENDED_PLATFORM 555 depends on NUMA 556 depends on SMP 557 depends on X86_X2APIC 558 depends on PCI_MMCONFIG 559 help 560 Adds support for Numascale NumaChip large-SMP systems. Needed to 561 enable more than ~168 cores. 562 If you don't have one of these, you should say N here. 563 564config X86_VSMP 565 bool "ScaleMP vSMP" 566 select HYPERVISOR_GUEST 567 select PARAVIRT 568 depends on X86_64 && PCI 569 depends on X86_EXTENDED_PLATFORM 570 depends on SMP 571 help 572 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 573 supposed to run on these EM64T-based machines. Only choose this option 574 if you have one of these machines. 575 576config X86_UV 577 bool "SGI Ultraviolet" 578 depends on X86_64 579 depends on X86_EXTENDED_PLATFORM 580 depends on NUMA 581 depends on EFI 582 depends on KEXEC_CORE 583 depends on X86_X2APIC 584 depends on PCI 585 help 586 This option is needed in order to support SGI Ultraviolet systems. 587 If you don't have one of these, you should say N here. 588 589# Following is an alphabetically sorted list of 32 bit extended platforms 590# Please maintain the alphabetic order if and when there are additions 591 592config X86_GOLDFISH 593 bool "Goldfish (Virtual Platform)" 594 depends on X86_EXTENDED_PLATFORM 595 help 596 Enable support for the Goldfish virtual platform used primarily 597 for Android development. Unless you are building for the Android 598 Goldfish emulator say N here. 599 600config X86_INTEL_CE 601 bool "CE4100 TV platform" 602 depends on PCI 603 depends on PCI_GODIRECT 604 depends on X86_IO_APIC 605 depends on X86_32 606 depends on X86_EXTENDED_PLATFORM 607 select X86_REBOOTFIXUPS 608 select OF 609 select OF_EARLY_FLATTREE 610 help 611 Select for the Intel CE media processor (CE4100) SOC. 612 This option compiles in support for the CE4100 SOC for settop 613 boxes and media devices. 614 615config X86_INTEL_MID 616 bool "Intel MID platform support" 617 depends on X86_EXTENDED_PLATFORM 618 depends on X86_PLATFORM_DEVICES 619 depends on PCI 620 depends on X86_64 || (PCI_GOANY && X86_32) 621 depends on X86_IO_APIC 622 select I2C 623 select DW_APB_TIMER 624 select INTEL_SCU_PCI 625 help 626 Select to build a kernel capable of supporting Intel MID (Mobile 627 Internet Device) platform systems which do not have the PCI legacy 628 interfaces. If you are building for a PC class system say N here. 629 630 Intel MID platforms are based on an Intel processor and chipset which 631 consume less power than most of the x86 derivatives. 632 633config X86_INTEL_QUARK 634 bool "Intel Quark platform support" 635 depends on X86_32 636 depends on X86_EXTENDED_PLATFORM 637 depends on X86_PLATFORM_DEVICES 638 depends on X86_TSC 639 depends on PCI 640 depends on PCI_GOANY 641 depends on X86_IO_APIC 642 select IOSF_MBI 643 select INTEL_IMR 644 select COMMON_CLK 645 help 646 Select to include support for Quark X1000 SoC. 647 Say Y here if you have a Quark based system such as the Arduino 648 compatible Intel Galileo. 649 650config X86_INTEL_LPSS 651 bool "Intel Low Power Subsystem Support" 652 depends on X86 && ACPI && PCI 653 select COMMON_CLK 654 select PINCTRL 655 select IOSF_MBI 656 help 657 Select to build support for Intel Low Power Subsystem such as 658 found on Intel Lynxpoint PCH. Selecting this option enables 659 things like clock tree (common clock framework) and pincontrol 660 which are needed by the LPSS peripheral drivers. 661 662config X86_AMD_PLATFORM_DEVICE 663 bool "AMD ACPI2Platform devices support" 664 depends on ACPI 665 select COMMON_CLK 666 select PINCTRL 667 help 668 Select to interpret AMD specific ACPI device to platform device 669 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 670 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 671 implemented under PINCTRL subsystem. 672 673config IOSF_MBI 674 tristate "Intel SoC IOSF Sideband support for SoC platforms" 675 depends on PCI 676 help 677 This option enables sideband register access support for Intel SoC 678 platforms. On these platforms the IOSF sideband is used in lieu of 679 MSR's for some register accesses, mostly but not limited to thermal 680 and power. Drivers may query the availability of this device to 681 determine if they need the sideband in order to work on these 682 platforms. The sideband is available on the following SoC products. 683 This list is not meant to be exclusive. 684 - BayTrail 685 - Braswell 686 - Quark 687 688 You should say Y if you are running a kernel on one of these SoC's. 689 690config IOSF_MBI_DEBUG 691 bool "Enable IOSF sideband access through debugfs" 692 depends on IOSF_MBI && DEBUG_FS 693 help 694 Select this option to expose the IOSF sideband access registers (MCR, 695 MDR, MCRX) through debugfs to write and read register information from 696 different units on the SoC. This is most useful for obtaining device 697 state information for debug and analysis. As this is a general access 698 mechanism, users of this option would have specific knowledge of the 699 device they want to access. 700 701 If you don't require the option or are in doubt, say N. 702 703config X86_RDC321X 704 bool "RDC R-321x SoC" 705 depends on X86_32 706 depends on X86_EXTENDED_PLATFORM 707 select M486 708 select X86_REBOOTFIXUPS 709 help 710 This option is needed for RDC R-321x system-on-chip, also known 711 as R-8610-(G). 712 If you don't have one of these chips, you should say N here. 713 714config X86_32_NON_STANDARD 715 bool "Support non-standard 32-bit SMP architectures" 716 depends on X86_32 && SMP 717 depends on X86_EXTENDED_PLATFORM 718 help 719 This option compiles in the bigsmp and STA2X11 default 720 subarchitectures. It is intended for a generic binary 721 kernel. If you select them all, kernel will probe it one by 722 one and will fallback to default. 723 724# Alphabetically sorted list of Non standard 32 bit platforms 725 726config X86_SUPPORTS_MEMORY_FAILURE 727 def_bool y 728 # MCE code calls memory_failure(): 729 depends on X86_MCE 730 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 731 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 732 depends on X86_64 || !SPARSEMEM 733 select ARCH_SUPPORTS_MEMORY_FAILURE 734 735config STA2X11 736 bool "STA2X11 Companion Chip Support" 737 depends on X86_32_NON_STANDARD && PCI 738 select SWIOTLB 739 select MFD_STA2X11 740 select GPIOLIB 741 help 742 This adds support for boards based on the STA2X11 IO-Hub, 743 a.k.a. "ConneXt". The chip is used in place of the standard 744 PC chipset, so all "standard" peripherals are missing. If this 745 option is selected the kernel will still be able to boot on 746 standard PC machines. 747 748config X86_32_IRIS 749 tristate "Eurobraille/Iris poweroff module" 750 depends on X86_32 751 help 752 The Iris machines from EuroBraille do not have APM or ACPI support 753 to shut themselves down properly. A special I/O sequence is 754 needed to do so, which is what this module does at 755 kernel shutdown. 756 757 This is only for Iris machines from EuroBraille. 758 759 If unused, say N. 760 761config SCHED_OMIT_FRAME_POINTER 762 def_bool y 763 prompt "Single-depth WCHAN output" 764 depends on X86 765 help 766 Calculate simpler /proc/<PID>/wchan values. If this option 767 is disabled then wchan values will recurse back to the 768 caller function. This provides more accurate wchan values, 769 at the expense of slightly more scheduling overhead. 770 771 If in doubt, say "Y". 772 773menuconfig HYPERVISOR_GUEST 774 bool "Linux guest support" 775 help 776 Say Y here to enable options for running Linux under various hyper- 777 visors. This option enables basic hypervisor detection and platform 778 setup. 779 780 If you say N, all options in this submenu will be skipped and 781 disabled, and Linux guest support won't be built in. 782 783if HYPERVISOR_GUEST 784 785config PARAVIRT 786 bool "Enable paravirtualization code" 787 depends on HAVE_STATIC_CALL 788 help 789 This changes the kernel so it can modify itself when it is run 790 under a hypervisor, potentially improving performance significantly 791 over full virtualization. However, when run without a hypervisor 792 the kernel is theoretically slower and slightly larger. 793 794config PARAVIRT_XXL 795 bool 796 797config PARAVIRT_DEBUG 798 bool "paravirt-ops debugging" 799 depends on PARAVIRT && DEBUG_KERNEL 800 help 801 Enable to debug paravirt_ops internals. Specifically, BUG if 802 a paravirt_op is missing when it is called. 803 804config PARAVIRT_SPINLOCKS 805 bool "Paravirtualization layer for spinlocks" 806 depends on PARAVIRT && SMP 807 help 808 Paravirtualized spinlocks allow a pvops backend to replace the 809 spinlock implementation with something virtualization-friendly 810 (for example, block the virtual CPU rather than spinning). 811 812 It has a minimal impact on native kernels and gives a nice performance 813 benefit on paravirtualized KVM / Xen kernels. 814 815 If you are unsure how to answer this question, answer Y. 816 817config X86_HV_CALLBACK_VECTOR 818 def_bool n 819 820source "arch/x86/xen/Kconfig" 821 822config KVM_GUEST 823 bool "KVM Guest support (including kvmclock)" 824 depends on PARAVIRT 825 select PARAVIRT_CLOCK 826 select ARCH_CPUIDLE_HALTPOLL 827 select X86_HV_CALLBACK_VECTOR 828 default y 829 help 830 This option enables various optimizations for running under the KVM 831 hypervisor. It includes a paravirtualized clock, so that instead 832 of relying on a PIT (or probably other) emulation by the 833 underlying device model, the host provides the guest with 834 timing infrastructure such as time of day, and system time 835 836config ARCH_CPUIDLE_HALTPOLL 837 def_bool n 838 prompt "Disable host haltpoll when loading haltpoll driver" 839 help 840 If virtualized under KVM, disable host haltpoll. 841 842config PVH 843 bool "Support for running PVH guests" 844 help 845 This option enables the PVH entry point for guest virtual machines 846 as specified in the x86/HVM direct boot ABI. 847 848config PARAVIRT_TIME_ACCOUNTING 849 bool "Paravirtual steal time accounting" 850 depends on PARAVIRT 851 help 852 Select this option to enable fine granularity task steal time 853 accounting. Time spent executing other tasks in parallel with 854 the current vCPU is discounted from the vCPU power. To account for 855 that, there can be a small performance impact. 856 857 If in doubt, say N here. 858 859config PARAVIRT_CLOCK 860 bool 861 862config JAILHOUSE_GUEST 863 bool "Jailhouse non-root cell support" 864 depends on X86_64 && PCI 865 select X86_PM_TIMER 866 help 867 This option allows to run Linux as guest in a Jailhouse non-root 868 cell. You can leave this option disabled if you only want to start 869 Jailhouse and run Linux afterwards in the root cell. 870 871config ACRN_GUEST 872 bool "ACRN Guest support" 873 depends on X86_64 874 select X86_HV_CALLBACK_VECTOR 875 help 876 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 877 a flexible, lightweight reference open-source hypervisor, built with 878 real-time and safety-criticality in mind. It is built for embedded 879 IOT with small footprint and real-time features. More details can be 880 found in https://projectacrn.org/. 881 882config INTEL_TDX_GUEST 883 bool "Intel TDX (Trust Domain Extensions) - Guest Support" 884 depends on X86_64 && CPU_SUP_INTEL 885 depends on X86_X2APIC 886 select ARCH_HAS_CC_PLATFORM 887 select X86_MEM_ENCRYPT 888 select X86_MCE 889 help 890 Support running as a guest under Intel TDX. Without this support, 891 the guest kernel can not boot or run under TDX. 892 TDX includes memory encryption and integrity capabilities 893 which protect the confidentiality and integrity of guest 894 memory contents and CPU state. TDX guests are protected from 895 some attacks from the VMM. 896 897endif # HYPERVISOR_GUEST 898 899source "arch/x86/Kconfig.cpu" 900 901config HPET_TIMER 902 def_bool X86_64 903 prompt "HPET Timer Support" if X86_32 904 help 905 Use the IA-PC HPET (High Precision Event Timer) to manage 906 time in preference to the PIT and RTC, if a HPET is 907 present. 908 HPET is the next generation timer replacing legacy 8254s. 909 The HPET provides a stable time base on SMP 910 systems, unlike the TSC, but it is more expensive to access, 911 as it is off-chip. The interface used is documented 912 in the HPET spec, revision 1. 913 914 You can safely choose Y here. However, HPET will only be 915 activated if the platform and the BIOS support this feature. 916 Otherwise the 8254 will be used for timing services. 917 918 Choose N to continue using the legacy 8254 timer. 919 920config HPET_EMULATE_RTC 921 def_bool y 922 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 923 924# Mark as expert because too many people got it wrong. 925# The code disables itself when not needed. 926config DMI 927 default y 928 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 929 bool "Enable DMI scanning" if EXPERT 930 help 931 Enabled scanning of DMI to identify machine quirks. Say Y 932 here unless you have verified that your setup is not 933 affected by entries in the DMI blacklist. Required by PNP 934 BIOS code. 935 936config GART_IOMMU 937 bool "Old AMD GART IOMMU support" 938 select DMA_OPS 939 select IOMMU_HELPER 940 select SWIOTLB 941 depends on X86_64 && PCI && AMD_NB 942 help 943 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 944 GART based hardware IOMMUs. 945 946 The GART supports full DMA access for devices with 32-bit access 947 limitations, on systems with more than 3 GB. This is usually needed 948 for USB, sound, many IDE/SATA chipsets and some other devices. 949 950 Newer systems typically have a modern AMD IOMMU, supported via 951 the CONFIG_AMD_IOMMU=y config option. 952 953 In normal configurations this driver is only active when needed: 954 there's more than 3 GB of memory and the system contains a 955 32-bit limited device. 956 957 If unsure, say Y. 958 959config BOOT_VESA_SUPPORT 960 bool 961 help 962 If true, at least one selected framebuffer driver can take advantage 963 of VESA video modes set at an early boot stage via the vga= parameter. 964 965config MAXSMP 966 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 967 depends on X86_64 && SMP && DEBUG_KERNEL 968 select CPUMASK_OFFSTACK 969 help 970 Enable maximum number of CPUS and NUMA Nodes for this architecture. 971 If unsure, say N. 972 973# 974# The maximum number of CPUs supported: 975# 976# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 977# and which can be configured interactively in the 978# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 979# 980# The ranges are different on 32-bit and 64-bit kernels, depending on 981# hardware capabilities and scalability features of the kernel. 982# 983# ( If MAXSMP is enabled we just use the highest possible value and disable 984# interactive configuration. ) 985# 986 987config NR_CPUS_RANGE_BEGIN 988 int 989 default NR_CPUS_RANGE_END if MAXSMP 990 default 1 if !SMP 991 default 2 992 993config NR_CPUS_RANGE_END 994 int 995 depends on X86_32 996 default 64 if SMP && X86_BIGSMP 997 default 8 if SMP && !X86_BIGSMP 998 default 1 if !SMP 999 1000config NR_CPUS_RANGE_END 1001 int 1002 depends on X86_64 1003 default 8192 if SMP && CPUMASK_OFFSTACK 1004 default 512 if SMP && !CPUMASK_OFFSTACK 1005 default 1 if !SMP 1006 1007config NR_CPUS_DEFAULT 1008 int 1009 depends on X86_32 1010 default 32 if X86_BIGSMP 1011 default 8 if SMP 1012 default 1 if !SMP 1013 1014config NR_CPUS_DEFAULT 1015 int 1016 depends on X86_64 1017 default 8192 if MAXSMP 1018 default 64 if SMP 1019 default 1 if !SMP 1020 1021config NR_CPUS 1022 int "Maximum number of CPUs" if SMP && !MAXSMP 1023 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1024 default NR_CPUS_DEFAULT 1025 help 1026 This allows you to specify the maximum number of CPUs which this 1027 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1028 supported value is 8192, otherwise the maximum value is 512. The 1029 minimum value which makes sense is 2. 1030 1031 This is purely to save memory: each supported CPU adds about 8KB 1032 to the kernel image. 1033 1034config SCHED_CLUSTER 1035 bool "Cluster scheduler support" 1036 depends on SMP 1037 default y 1038 help 1039 Cluster scheduler support improves the CPU scheduler's decision 1040 making when dealing with machines that have clusters of CPUs. 1041 Cluster usually means a couple of CPUs which are placed closely 1042 by sharing mid-level caches, last-level cache tags or internal 1043 busses. 1044 1045config SCHED_SMT 1046 def_bool y if SMP 1047 1048config SCHED_MC 1049 def_bool y 1050 prompt "Multi-core scheduler support" 1051 depends on SMP 1052 help 1053 Multi-core scheduler support improves the CPU scheduler's decision 1054 making when dealing with multi-core CPU chips at a cost of slightly 1055 increased overhead in some places. If unsure say N here. 1056 1057config SCHED_MC_PRIO 1058 bool "CPU core priorities scheduler support" 1059 depends on SCHED_MC && CPU_SUP_INTEL 1060 select X86_INTEL_PSTATE 1061 select CPU_FREQ 1062 default y 1063 help 1064 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1065 core ordering determined at manufacturing time, which allows 1066 certain cores to reach higher turbo frequencies (when running 1067 single threaded workloads) than others. 1068 1069 Enabling this kernel feature teaches the scheduler about 1070 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1071 scheduler's CPU selection logic accordingly, so that higher 1072 overall system performance can be achieved. 1073 1074 This feature will have no effect on CPUs without this feature. 1075 1076 If unsure say Y here. 1077 1078config UP_LATE_INIT 1079 def_bool y 1080 depends on !SMP && X86_LOCAL_APIC 1081 1082config X86_UP_APIC 1083 bool "Local APIC support on uniprocessors" if !PCI_MSI 1084 default PCI_MSI 1085 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1086 help 1087 A local APIC (Advanced Programmable Interrupt Controller) is an 1088 integrated interrupt controller in the CPU. If you have a single-CPU 1089 system which has a processor with a local APIC, you can say Y here to 1090 enable and use it. If you say Y here even though your machine doesn't 1091 have a local APIC, then the kernel will still run with no slowdown at 1092 all. The local APIC supports CPU-generated self-interrupts (timer, 1093 performance counters), and the NMI watchdog which detects hard 1094 lockups. 1095 1096config X86_UP_IOAPIC 1097 bool "IO-APIC support on uniprocessors" 1098 depends on X86_UP_APIC 1099 help 1100 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1101 SMP-capable replacement for PC-style interrupt controllers. Most 1102 SMP systems and many recent uniprocessor systems have one. 1103 1104 If you have a single-CPU system with an IO-APIC, you can say Y here 1105 to use it. If you say Y here even though your machine doesn't have 1106 an IO-APIC, then the kernel will still run with no slowdown at all. 1107 1108config X86_LOCAL_APIC 1109 def_bool y 1110 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1111 select IRQ_DOMAIN_HIERARCHY 1112 1113config X86_IO_APIC 1114 def_bool y 1115 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1116 1117config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1118 bool "Reroute for broken boot IRQs" 1119 depends on X86_IO_APIC 1120 help 1121 This option enables a workaround that fixes a source of 1122 spurious interrupts. This is recommended when threaded 1123 interrupt handling is used on systems where the generation of 1124 superfluous "boot interrupts" cannot be disabled. 1125 1126 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1127 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1128 kernel does during interrupt handling). On chipsets where this 1129 boot IRQ generation cannot be disabled, this workaround keeps 1130 the original IRQ line masked so that only the equivalent "boot 1131 IRQ" is delivered to the CPUs. The workaround also tells the 1132 kernel to set up the IRQ handler on the boot IRQ line. In this 1133 way only one interrupt is delivered to the kernel. Otherwise 1134 the spurious second interrupt may cause the kernel to bring 1135 down (vital) interrupt lines. 1136 1137 Only affects "broken" chipsets. Interrupt sharing may be 1138 increased on these systems. 1139 1140config X86_MCE 1141 bool "Machine Check / overheating reporting" 1142 select GENERIC_ALLOCATOR 1143 default y 1144 help 1145 Machine Check support allows the processor to notify the 1146 kernel if it detects a problem (e.g. overheating, data corruption). 1147 The action the kernel takes depends on the severity of the problem, 1148 ranging from warning messages to halting the machine. 1149 1150config X86_MCELOG_LEGACY 1151 bool "Support for deprecated /dev/mcelog character device" 1152 depends on X86_MCE 1153 help 1154 Enable support for /dev/mcelog which is needed by the old mcelog 1155 userspace logging daemon. Consider switching to the new generation 1156 rasdaemon solution. 1157 1158config X86_MCE_INTEL 1159 def_bool y 1160 prompt "Intel MCE features" 1161 depends on X86_MCE && X86_LOCAL_APIC 1162 help 1163 Additional support for intel specific MCE features such as 1164 the thermal monitor. 1165 1166config X86_MCE_AMD 1167 def_bool y 1168 prompt "AMD MCE features" 1169 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1170 help 1171 Additional support for AMD specific MCE features such as 1172 the DRAM Error Threshold. 1173 1174config X86_ANCIENT_MCE 1175 bool "Support for old Pentium 5 / WinChip machine checks" 1176 depends on X86_32 && X86_MCE 1177 help 1178 Include support for machine check handling on old Pentium 5 or WinChip 1179 systems. These typically need to be enabled explicitly on the command 1180 line. 1181 1182config X86_MCE_THRESHOLD 1183 depends on X86_MCE_AMD || X86_MCE_INTEL 1184 def_bool y 1185 1186config X86_MCE_INJECT 1187 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1188 tristate "Machine check injector support" 1189 help 1190 Provide support for injecting machine checks for testing purposes. 1191 If you don't know what a machine check is and you don't do kernel 1192 QA it is safe to say n. 1193 1194source "arch/x86/events/Kconfig" 1195 1196config X86_LEGACY_VM86 1197 bool "Legacy VM86 support" 1198 depends on X86_32 1199 help 1200 This option allows user programs to put the CPU into V8086 1201 mode, which is an 80286-era approximation of 16-bit real mode. 1202 1203 Some very old versions of X and/or vbetool require this option 1204 for user mode setting. Similarly, DOSEMU will use it if 1205 available to accelerate real mode DOS programs. However, any 1206 recent version of DOSEMU, X, or vbetool should be fully 1207 functional even without kernel VM86 support, as they will all 1208 fall back to software emulation. Nevertheless, if you are using 1209 a 16-bit DOS program where 16-bit performance matters, vm86 1210 mode might be faster than emulation and you might want to 1211 enable this option. 1212 1213 Note that any app that works on a 64-bit kernel is unlikely to 1214 need this option, as 64-bit kernels don't, and can't, support 1215 V8086 mode. This option is also unrelated to 16-bit protected 1216 mode and is not needed to run most 16-bit programs under Wine. 1217 1218 Enabling this option increases the complexity of the kernel 1219 and slows down exception handling a tiny bit. 1220 1221 If unsure, say N here. 1222 1223config VM86 1224 bool 1225 default X86_LEGACY_VM86 1226 1227config X86_16BIT 1228 bool "Enable support for 16-bit segments" if EXPERT 1229 default y 1230 depends on MODIFY_LDT_SYSCALL 1231 help 1232 This option is required by programs like Wine to run 16-bit 1233 protected mode legacy code on x86 processors. Disabling 1234 this option saves about 300 bytes on i386, or around 6K text 1235 plus 16K runtime memory on x86-64, 1236 1237config X86_ESPFIX32 1238 def_bool y 1239 depends on X86_16BIT && X86_32 1240 1241config X86_ESPFIX64 1242 def_bool y 1243 depends on X86_16BIT && X86_64 1244 1245config X86_VSYSCALL_EMULATION 1246 bool "Enable vsyscall emulation" if EXPERT 1247 default y 1248 depends on X86_64 1249 help 1250 This enables emulation of the legacy vsyscall page. Disabling 1251 it is roughly equivalent to booting with vsyscall=none, except 1252 that it will also disable the helpful warning if a program 1253 tries to use a vsyscall. With this option set to N, offending 1254 programs will just segfault, citing addresses of the form 1255 0xffffffffff600?00. 1256 1257 This option is required by many programs built before 2013, and 1258 care should be used even with newer programs if set to N. 1259 1260 Disabling this option saves about 7K of kernel size and 1261 possibly 4K of additional runtime pagetable memory. 1262 1263config X86_IOPL_IOPERM 1264 bool "IOPERM and IOPL Emulation" 1265 default y 1266 help 1267 This enables the ioperm() and iopl() syscalls which are necessary 1268 for legacy applications. 1269 1270 Legacy IOPL support is an overbroad mechanism which allows user 1271 space aside of accessing all 65536 I/O ports also to disable 1272 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1273 capabilities and permission from potentially active security 1274 modules. 1275 1276 The emulation restricts the functionality of the syscall to 1277 only allowing the full range I/O port access, but prevents the 1278 ability to disable interrupts from user space which would be 1279 granted if the hardware IOPL mechanism would be used. 1280 1281config TOSHIBA 1282 tristate "Toshiba Laptop support" 1283 depends on X86_32 1284 help 1285 This adds a driver to safely access the System Management Mode of 1286 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1287 not work on models with a Phoenix BIOS. The System Management Mode 1288 is used to set the BIOS and power saving options on Toshiba portables. 1289 1290 For information on utilities to make use of this driver see the 1291 Toshiba Linux utilities web site at: 1292 <http://www.buzzard.org.uk/toshiba/>. 1293 1294 Say Y if you intend to run this kernel on a Toshiba portable. 1295 Say N otherwise. 1296 1297config X86_REBOOTFIXUPS 1298 bool "Enable X86 board specific fixups for reboot" 1299 depends on X86_32 1300 help 1301 This enables chipset and/or board specific fixups to be done 1302 in order to get reboot to work correctly. This is only needed on 1303 some combinations of hardware and BIOS. The symptom, for which 1304 this config is intended, is when reboot ends with a stalled/hung 1305 system. 1306 1307 Currently, the only fixup is for the Geode machines using 1308 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1309 1310 Say Y if you want to enable the fixup. Currently, it's safe to 1311 enable this option even if you don't need it. 1312 Say N otherwise. 1313 1314config MICROCODE 1315 bool "CPU microcode loading support" 1316 default y 1317 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1318 help 1319 If you say Y here, you will be able to update the microcode on 1320 Intel and AMD processors. The Intel support is for the IA32 family, 1321 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1322 AMD support is for families 0x10 and later. You will obviously need 1323 the actual microcode binary data itself which is not shipped with 1324 the Linux kernel. 1325 1326 The preferred method to load microcode from a detached initrd is described 1327 in Documentation/x86/microcode.rst. For that you need to enable 1328 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1329 initrd for microcode blobs. 1330 1331 In addition, you can build the microcode into the kernel. For that you 1332 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1333 config option. 1334 1335config MICROCODE_INTEL 1336 bool "Intel microcode loading support" 1337 depends on CPU_SUP_INTEL && MICROCODE 1338 default MICROCODE 1339 help 1340 This options enables microcode patch loading support for Intel 1341 processors. 1342 1343 For the current Intel microcode data package go to 1344 <https://downloadcenter.intel.com> and search for 1345 'Linux Processor Microcode Data File'. 1346 1347config MICROCODE_AMD 1348 bool "AMD microcode loading support" 1349 depends on CPU_SUP_AMD && MICROCODE 1350 help 1351 If you select this option, microcode patch loading support for AMD 1352 processors will be enabled. 1353 1354config MICROCODE_LATE_LOADING 1355 bool "Late microcode loading (DANGEROUS)" 1356 default n 1357 depends on MICROCODE 1358 help 1359 Loading microcode late, when the system is up and executing instructions 1360 is a tricky business and should be avoided if possible. Just the sequence 1361 of synchronizing all cores and SMT threads is one fragile dance which does 1362 not guarantee that cores might not softlock after the loading. Therefore, 1363 use this at your own risk. Late loading taints the kernel too. 1364 1365config X86_MSR 1366 tristate "/dev/cpu/*/msr - Model-specific register support" 1367 help 1368 This device gives privileged processes access to the x86 1369 Model-Specific Registers (MSRs). It is a character device with 1370 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1371 MSR accesses are directed to a specific CPU on multi-processor 1372 systems. 1373 1374config X86_CPUID 1375 tristate "/dev/cpu/*/cpuid - CPU information support" 1376 help 1377 This device gives processes access to the x86 CPUID instruction to 1378 be executed on a specific processor. It is a character device 1379 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1380 /dev/cpu/31/cpuid. 1381 1382choice 1383 prompt "High Memory Support" 1384 default HIGHMEM4G 1385 depends on X86_32 1386 1387config NOHIGHMEM 1388 bool "off" 1389 help 1390 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1391 However, the address space of 32-bit x86 processors is only 4 1392 Gigabytes large. That means that, if you have a large amount of 1393 physical memory, not all of it can be "permanently mapped" by the 1394 kernel. The physical memory that's not permanently mapped is called 1395 "high memory". 1396 1397 If you are compiling a kernel which will never run on a machine with 1398 more than 1 Gigabyte total physical RAM, answer "off" here (default 1399 choice and suitable for most users). This will result in a "3GB/1GB" 1400 split: 3GB are mapped so that each process sees a 3GB virtual memory 1401 space and the remaining part of the 4GB virtual memory space is used 1402 by the kernel to permanently map as much physical memory as 1403 possible. 1404 1405 If the machine has between 1 and 4 Gigabytes physical RAM, then 1406 answer "4GB" here. 1407 1408 If more than 4 Gigabytes is used then answer "64GB" here. This 1409 selection turns Intel PAE (Physical Address Extension) mode on. 1410 PAE implements 3-level paging on IA32 processors. PAE is fully 1411 supported by Linux, PAE mode is implemented on all recent Intel 1412 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1413 then the kernel will not boot on CPUs that don't support PAE! 1414 1415 The actual amount of total physical memory will either be 1416 auto detected or can be forced by using a kernel command line option 1417 such as "mem=256M". (Try "man bootparam" or see the documentation of 1418 your boot loader (lilo or loadlin) about how to pass options to the 1419 kernel at boot time.) 1420 1421 If unsure, say "off". 1422 1423config HIGHMEM4G 1424 bool "4GB" 1425 help 1426 Select this if you have a 32-bit processor and between 1 and 4 1427 gigabytes of physical RAM. 1428 1429config HIGHMEM64G 1430 bool "64GB" 1431 depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6 1432 select X86_PAE 1433 help 1434 Select this if you have a 32-bit processor and more than 4 1435 gigabytes of physical RAM. 1436 1437endchoice 1438 1439choice 1440 prompt "Memory split" if EXPERT 1441 default VMSPLIT_3G 1442 depends on X86_32 1443 help 1444 Select the desired split between kernel and user memory. 1445 1446 If the address range available to the kernel is less than the 1447 physical memory installed, the remaining memory will be available 1448 as "high memory". Accessing high memory is a little more costly 1449 than low memory, as it needs to be mapped into the kernel first. 1450 Note that increasing the kernel address space limits the range 1451 available to user programs, making the address space there 1452 tighter. Selecting anything other than the default 3G/1G split 1453 will also likely make your kernel incompatible with binary-only 1454 kernel modules. 1455 1456 If you are not absolutely sure what you are doing, leave this 1457 option alone! 1458 1459 config VMSPLIT_3G 1460 bool "3G/1G user/kernel split" 1461 config VMSPLIT_3G_OPT 1462 depends on !X86_PAE 1463 bool "3G/1G user/kernel split (for full 1G low memory)" 1464 config VMSPLIT_2G 1465 bool "2G/2G user/kernel split" 1466 config VMSPLIT_2G_OPT 1467 depends on !X86_PAE 1468 bool "2G/2G user/kernel split (for full 2G low memory)" 1469 config VMSPLIT_1G 1470 bool "1G/3G user/kernel split" 1471endchoice 1472 1473config PAGE_OFFSET 1474 hex 1475 default 0xB0000000 if VMSPLIT_3G_OPT 1476 default 0x80000000 if VMSPLIT_2G 1477 default 0x78000000 if VMSPLIT_2G_OPT 1478 default 0x40000000 if VMSPLIT_1G 1479 default 0xC0000000 1480 depends on X86_32 1481 1482config HIGHMEM 1483 def_bool y 1484 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1485 1486config X86_PAE 1487 bool "PAE (Physical Address Extension) Support" 1488 depends on X86_32 && !HIGHMEM4G 1489 select PHYS_ADDR_T_64BIT 1490 select SWIOTLB 1491 help 1492 PAE is required for NX support, and furthermore enables 1493 larger swapspace support for non-overcommit purposes. It 1494 has the cost of more pagetable lookup overhead, and also 1495 consumes more pagetable space per process. 1496 1497config X86_5LEVEL 1498 bool "Enable 5-level page tables support" 1499 default y 1500 select DYNAMIC_MEMORY_LAYOUT 1501 select SPARSEMEM_VMEMMAP 1502 depends on X86_64 1503 help 1504 5-level paging enables access to larger address space: 1505 upto 128 PiB of virtual address space and 4 PiB of 1506 physical address space. 1507 1508 It will be supported by future Intel CPUs. 1509 1510 A kernel with the option enabled can be booted on machines that 1511 support 4- or 5-level paging. 1512 1513 See Documentation/x86/x86_64/5level-paging.rst for more 1514 information. 1515 1516 Say N if unsure. 1517 1518config X86_DIRECT_GBPAGES 1519 def_bool y 1520 depends on X86_64 1521 help 1522 Certain kernel features effectively disable kernel 1523 linear 1 GB mappings (even if the CPU otherwise 1524 supports them), so don't confuse the user by printing 1525 that we have them enabled. 1526 1527config X86_CPA_STATISTICS 1528 bool "Enable statistic for Change Page Attribute" 1529 depends on DEBUG_FS 1530 help 1531 Expose statistics about the Change Page Attribute mechanism, which 1532 helps to determine the effectiveness of preserving large and huge 1533 page mappings when mapping protections are changed. 1534 1535config X86_MEM_ENCRYPT 1536 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1537 select DYNAMIC_PHYSICAL_MASK 1538 def_bool n 1539 1540config AMD_MEM_ENCRYPT 1541 bool "AMD Secure Memory Encryption (SME) support" 1542 depends on X86_64 && CPU_SUP_AMD 1543 select DMA_COHERENT_POOL 1544 select ARCH_USE_MEMREMAP_PROT 1545 select INSTRUCTION_DECODER 1546 select ARCH_HAS_CC_PLATFORM 1547 select X86_MEM_ENCRYPT 1548 help 1549 Say yes to enable support for the encryption of system memory. 1550 This requires an AMD processor that supports Secure Memory 1551 Encryption (SME). 1552 1553config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1554 bool "Activate AMD Secure Memory Encryption (SME) by default" 1555 depends on AMD_MEM_ENCRYPT 1556 help 1557 Say yes to have system memory encrypted by default if running on 1558 an AMD processor that supports Secure Memory Encryption (SME). 1559 1560 If set to Y, then the encryption of system memory can be 1561 deactivated with the mem_encrypt=off command line option. 1562 1563 If set to N, then the encryption of system memory can be 1564 activated with the mem_encrypt=on command line option. 1565 1566# Common NUMA Features 1567config NUMA 1568 bool "NUMA Memory Allocation and Scheduler Support" 1569 depends on SMP 1570 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1571 default y if X86_BIGSMP 1572 select USE_PERCPU_NUMA_NODE_ID 1573 help 1574 Enable NUMA (Non-Uniform Memory Access) support. 1575 1576 The kernel will try to allocate memory used by a CPU on the 1577 local memory controller of the CPU and add some more 1578 NUMA awareness to the kernel. 1579 1580 For 64-bit this is recommended if the system is Intel Core i7 1581 (or later), AMD Opteron, or EM64T NUMA. 1582 1583 For 32-bit this is only needed if you boot a 32-bit 1584 kernel on a 64-bit NUMA platform. 1585 1586 Otherwise, you should say N. 1587 1588config AMD_NUMA 1589 def_bool y 1590 prompt "Old style AMD Opteron NUMA detection" 1591 depends on X86_64 && NUMA && PCI 1592 help 1593 Enable AMD NUMA node topology detection. You should say Y here if 1594 you have a multi processor AMD system. This uses an old method to 1595 read the NUMA configuration directly from the builtin Northbridge 1596 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1597 which also takes priority if both are compiled in. 1598 1599config X86_64_ACPI_NUMA 1600 def_bool y 1601 prompt "ACPI NUMA detection" 1602 depends on X86_64 && NUMA && ACPI && PCI 1603 select ACPI_NUMA 1604 help 1605 Enable ACPI SRAT based node topology detection. 1606 1607config NUMA_EMU 1608 bool "NUMA emulation" 1609 depends on NUMA 1610 help 1611 Enable NUMA emulation. A flat machine will be split 1612 into virtual nodes when booted with "numa=fake=N", where N is the 1613 number of nodes. This is only useful for debugging. 1614 1615config NODES_SHIFT 1616 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1617 range 1 10 1618 default "10" if MAXSMP 1619 default "6" if X86_64 1620 default "3" 1621 depends on NUMA 1622 help 1623 Specify the maximum number of NUMA Nodes available on the target 1624 system. Increases memory reserved to accommodate various tables. 1625 1626config ARCH_FLATMEM_ENABLE 1627 def_bool y 1628 depends on X86_32 && !NUMA 1629 1630config ARCH_SPARSEMEM_ENABLE 1631 def_bool y 1632 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1633 select SPARSEMEM_STATIC if X86_32 1634 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1635 1636config ARCH_SPARSEMEM_DEFAULT 1637 def_bool X86_64 || (NUMA && X86_32) 1638 1639config ARCH_SELECT_MEMORY_MODEL 1640 def_bool y 1641 depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE 1642 1643config ARCH_MEMORY_PROBE 1644 bool "Enable sysfs memory/probe interface" 1645 depends on MEMORY_HOTPLUG 1646 help 1647 This option enables a sysfs memory/probe interface for testing. 1648 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1649 If you are unsure how to answer this question, answer N. 1650 1651config ARCH_PROC_KCORE_TEXT 1652 def_bool y 1653 depends on X86_64 && PROC_KCORE 1654 1655config ILLEGAL_POINTER_VALUE 1656 hex 1657 default 0 if X86_32 1658 default 0xdead000000000000 if X86_64 1659 1660config X86_PMEM_LEGACY_DEVICE 1661 bool 1662 1663config X86_PMEM_LEGACY 1664 tristate "Support non-standard NVDIMMs and ADR protected memory" 1665 depends on PHYS_ADDR_T_64BIT 1666 depends on BLK_DEV 1667 select X86_PMEM_LEGACY_DEVICE 1668 select NUMA_KEEP_MEMINFO if NUMA 1669 select LIBNVDIMM 1670 help 1671 Treat memory marked using the non-standard e820 type of 12 as used 1672 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1673 The kernel will offer these regions to the 'pmem' driver so 1674 they can be used for persistent storage. 1675 1676 Say Y if unsure. 1677 1678config HIGHPTE 1679 bool "Allocate 3rd-level pagetables from highmem" 1680 depends on HIGHMEM 1681 help 1682 The VM uses one page table entry for each page of physical memory. 1683 For systems with a lot of RAM, this can be wasteful of precious 1684 low memory. Setting this option will put user-space page table 1685 entries in high memory. 1686 1687config X86_CHECK_BIOS_CORRUPTION 1688 bool "Check for low memory corruption" 1689 help 1690 Periodically check for memory corruption in low memory, which 1691 is suspected to be caused by BIOS. Even when enabled in the 1692 configuration, it is disabled at runtime. Enable it by 1693 setting "memory_corruption_check=1" on the kernel command 1694 line. By default it scans the low 64k of memory every 60 1695 seconds; see the memory_corruption_check_size and 1696 memory_corruption_check_period parameters in 1697 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1698 1699 When enabled with the default parameters, this option has 1700 almost no overhead, as it reserves a relatively small amount 1701 of memory and scans it infrequently. It both detects corruption 1702 and prevents it from affecting the running system. 1703 1704 It is, however, intended as a diagnostic tool; if repeatable 1705 BIOS-originated corruption always affects the same memory, 1706 you can use memmap= to prevent the kernel from using that 1707 memory. 1708 1709config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1710 bool "Set the default setting of memory_corruption_check" 1711 depends on X86_CHECK_BIOS_CORRUPTION 1712 default y 1713 help 1714 Set whether the default state of memory_corruption_check is 1715 on or off. 1716 1717config MATH_EMULATION 1718 bool 1719 depends on MODIFY_LDT_SYSCALL 1720 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1721 help 1722 Linux can emulate a math coprocessor (used for floating point 1723 operations) if you don't have one. 486DX and Pentium processors have 1724 a math coprocessor built in, 486SX and 386 do not, unless you added 1725 a 487DX or 387, respectively. (The messages during boot time can 1726 give you some hints here ["man dmesg"].) Everyone needs either a 1727 coprocessor or this emulation. 1728 1729 If you don't have a math coprocessor, you need to say Y here; if you 1730 say Y here even though you have a coprocessor, the coprocessor will 1731 be used nevertheless. (This behavior can be changed with the kernel 1732 command line option "no387", which comes handy if your coprocessor 1733 is broken. Try "man bootparam" or see the documentation of your boot 1734 loader (lilo or loadlin) about how to pass options to the kernel at 1735 boot time.) This means that it is a good idea to say Y here if you 1736 intend to use this kernel on different machines. 1737 1738 More information about the internals of the Linux math coprocessor 1739 emulation can be found in <file:arch/x86/math-emu/README>. 1740 1741 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1742 kernel, it won't hurt. 1743 1744config MTRR 1745 def_bool y 1746 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1747 help 1748 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1749 the Memory Type Range Registers (MTRRs) may be used to control 1750 processor access to memory ranges. This is most useful if you have 1751 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1752 allows bus write transfers to be combined into a larger transfer 1753 before bursting over the PCI/AGP bus. This can increase performance 1754 of image write operations 2.5 times or more. Saying Y here creates a 1755 /proc/mtrr file which may be used to manipulate your processor's 1756 MTRRs. Typically the X server should use this. 1757 1758 This code has a reasonably generic interface so that similar 1759 control registers on other processors can be easily supported 1760 as well: 1761 1762 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1763 Registers (ARRs) which provide a similar functionality to MTRRs. For 1764 these, the ARRs are used to emulate the MTRRs. 1765 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1766 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1767 write-combining. All of these processors are supported by this code 1768 and it makes sense to say Y here if you have one of them. 1769 1770 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1771 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1772 can lead to all sorts of problems, so it's good to say Y here. 1773 1774 You can safely say Y even if your machine doesn't have MTRRs, you'll 1775 just add about 9 KB to your kernel. 1776 1777 See <file:Documentation/x86/mtrr.rst> for more information. 1778 1779config MTRR_SANITIZER 1780 def_bool y 1781 prompt "MTRR cleanup support" 1782 depends on MTRR 1783 help 1784 Convert MTRR layout from continuous to discrete, so X drivers can 1785 add writeback entries. 1786 1787 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1788 The largest mtrr entry size for a continuous block can be set with 1789 mtrr_chunk_size. 1790 1791 If unsure, say Y. 1792 1793config MTRR_SANITIZER_ENABLE_DEFAULT 1794 int "MTRR cleanup enable value (0-1)" 1795 range 0 1 1796 default "0" 1797 depends on MTRR_SANITIZER 1798 help 1799 Enable mtrr cleanup default value 1800 1801config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1802 int "MTRR cleanup spare reg num (0-7)" 1803 range 0 7 1804 default "1" 1805 depends on MTRR_SANITIZER 1806 help 1807 mtrr cleanup spare entries default, it can be changed via 1808 mtrr_spare_reg_nr=N on the kernel command line. 1809 1810config X86_PAT 1811 def_bool y 1812 prompt "x86 PAT support" if EXPERT 1813 depends on MTRR 1814 help 1815 Use PAT attributes to setup page level cache control. 1816 1817 PATs are the modern equivalents of MTRRs and are much more 1818 flexible than MTRRs. 1819 1820 Say N here if you see bootup problems (boot crash, boot hang, 1821 spontaneous reboots) or a non-working video driver. 1822 1823 If unsure, say Y. 1824 1825config ARCH_USES_PG_UNCACHED 1826 def_bool y 1827 depends on X86_PAT 1828 1829config X86_UMIP 1830 def_bool y 1831 prompt "User Mode Instruction Prevention" if EXPERT 1832 help 1833 User Mode Instruction Prevention (UMIP) is a security feature in 1834 some x86 processors. If enabled, a general protection fault is 1835 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1836 executed in user mode. These instructions unnecessarily expose 1837 information about the hardware state. 1838 1839 The vast majority of applications do not use these instructions. 1840 For the very few that do, software emulation is provided in 1841 specific cases in protected and virtual-8086 modes. Emulated 1842 results are dummy. 1843 1844config CC_HAS_IBT 1845 # GCC >= 9 and binutils >= 2.29 1846 # Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654 1847 # Clang/LLVM >= 14 1848 # https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f 1849 # https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332 1850 def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \ 1851 (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \ 1852 $(as-instr,endbr64) 1853 1854config X86_KERNEL_IBT 1855 prompt "Indirect Branch Tracking" 1856 def_bool y 1857 depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL 1858 # https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f 1859 depends on !LD_IS_LLD || LLD_VERSION >= 140000 1860 select OBJTOOL 1861 help 1862 Build the kernel with support for Indirect Branch Tracking, a 1863 hardware support course-grain forward-edge Control Flow Integrity 1864 protection. It enforces that all indirect calls must land on 1865 an ENDBR instruction, as such, the compiler will instrument the 1866 code with them to make this happen. 1867 1868 In addition to building the kernel with IBT, seal all functions that 1869 are not indirect call targets, avoiding them ever becoming one. 1870 1871 This requires LTO like objtool runs and will slow down the build. It 1872 does significantly reduce the number of ENDBR instructions in the 1873 kernel image. 1874 1875config X86_INTEL_MEMORY_PROTECTION_KEYS 1876 prompt "Memory Protection Keys" 1877 def_bool y 1878 # Note: only available in 64-bit mode 1879 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1880 select ARCH_USES_HIGH_VMA_FLAGS 1881 select ARCH_HAS_PKEYS 1882 help 1883 Memory Protection Keys provides a mechanism for enforcing 1884 page-based protections, but without requiring modification of the 1885 page tables when an application changes protection domains. 1886 1887 For details, see Documentation/core-api/protection-keys.rst 1888 1889 If unsure, say y. 1890 1891choice 1892 prompt "TSX enable mode" 1893 depends on CPU_SUP_INTEL 1894 default X86_INTEL_TSX_MODE_OFF 1895 help 1896 Intel's TSX (Transactional Synchronization Extensions) feature 1897 allows to optimize locking protocols through lock elision which 1898 can lead to a noticeable performance boost. 1899 1900 On the other hand it has been shown that TSX can be exploited 1901 to form side channel attacks (e.g. TAA) and chances are there 1902 will be more of those attacks discovered in the future. 1903 1904 Therefore TSX is not enabled by default (aka tsx=off). An admin 1905 might override this decision by tsx=on the command line parameter. 1906 Even with TSX enabled, the kernel will attempt to enable the best 1907 possible TAA mitigation setting depending on the microcode available 1908 for the particular machine. 1909 1910 This option allows to set the default tsx mode between tsx=on, =off 1911 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1912 details. 1913 1914 Say off if not sure, auto if TSX is in use but it should be used on safe 1915 platforms or on if TSX is in use and the security aspect of tsx is not 1916 relevant. 1917 1918config X86_INTEL_TSX_MODE_OFF 1919 bool "off" 1920 help 1921 TSX is disabled if possible - equals to tsx=off command line parameter. 1922 1923config X86_INTEL_TSX_MODE_ON 1924 bool "on" 1925 help 1926 TSX is always enabled on TSX capable HW - equals the tsx=on command 1927 line parameter. 1928 1929config X86_INTEL_TSX_MODE_AUTO 1930 bool "auto" 1931 help 1932 TSX is enabled on TSX capable HW that is believed to be safe against 1933 side channel attacks- equals the tsx=auto command line parameter. 1934endchoice 1935 1936config X86_SGX 1937 bool "Software Guard eXtensions (SGX)" 1938 depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC 1939 depends on CRYPTO=y 1940 depends on CRYPTO_SHA256=y 1941 select SRCU 1942 select MMU_NOTIFIER 1943 select NUMA_KEEP_MEMINFO if NUMA 1944 select XARRAY_MULTI 1945 help 1946 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1947 that can be used by applications to set aside private regions of code 1948 and data, referred to as enclaves. An enclave's private memory can 1949 only be accessed by code running within the enclave. Accesses from 1950 outside the enclave, including other enclaves, are disallowed by 1951 hardware. 1952 1953 If unsure, say N. 1954 1955config EFI 1956 bool "EFI runtime service support" 1957 depends on ACPI 1958 select UCS2_STRING 1959 select EFI_RUNTIME_WRAPPERS 1960 select ARCH_USE_MEMREMAP_PROT 1961 help 1962 This enables the kernel to use EFI runtime services that are 1963 available (such as the EFI variable services). 1964 1965 This option is only useful on systems that have EFI firmware. 1966 In addition, you should use the latest ELILO loader available 1967 at <http://elilo.sourceforge.net> in order to take advantage 1968 of EFI runtime services. However, even with this option, the 1969 resultant kernel should continue to boot on existing non-EFI 1970 platforms. 1971 1972config EFI_STUB 1973 bool "EFI stub support" 1974 depends on EFI 1975 select RELOCATABLE 1976 help 1977 This kernel feature allows a bzImage to be loaded directly 1978 by EFI firmware without the use of a bootloader. 1979 1980 See Documentation/admin-guide/efi-stub.rst for more information. 1981 1982config EFI_HANDOVER_PROTOCOL 1983 bool "EFI handover protocol (DEPRECATED)" 1984 depends on EFI_STUB 1985 default y 1986 help 1987 Select this in order to include support for the deprecated EFI 1988 handover protocol, which defines alternative entry points into the 1989 EFI stub. This is a practice that has no basis in the UEFI 1990 specification, and requires a priori knowledge on the part of the 1991 bootloader about Linux/x86 specific ways of passing the command line 1992 and initrd, and where in memory those assets may be loaded. 1993 1994 If in doubt, say Y. Even though the corresponding support is not 1995 present in upstream GRUB or other bootloaders, most distros build 1996 GRUB with numerous downstream patches applied, and may rely on the 1997 handover protocol as as result. 1998 1999config EFI_MIXED 2000 bool "EFI mixed-mode support" 2001 depends on EFI_STUB && X86_64 2002 help 2003 Enabling this feature allows a 64-bit kernel to be booted 2004 on a 32-bit firmware, provided that your CPU supports 64-bit 2005 mode. 2006 2007 Note that it is not possible to boot a mixed-mode enabled 2008 kernel via the EFI boot stub - a bootloader that supports 2009 the EFI handover protocol must be used. 2010 2011 If unsure, say N. 2012 2013config EFI_FAKE_MEMMAP 2014 bool "Enable EFI fake memory map" 2015 depends on EFI 2016 help 2017 Saying Y here will enable "efi_fake_mem" boot option. By specifying 2018 this parameter, you can add arbitrary attribute to specific memory 2019 range by updating original (firmware provided) EFI memmap. This is 2020 useful for debugging of EFI memmap related feature, e.g., Address 2021 Range Mirroring feature. 2022 2023config EFI_MAX_FAKE_MEM 2024 int "maximum allowable number of ranges in efi_fake_mem boot option" 2025 depends on EFI_FAKE_MEMMAP 2026 range 1 128 2027 default 8 2028 help 2029 Maximum allowable number of ranges in efi_fake_mem boot option. 2030 Ranges can be set up to this value using comma-separated list. 2031 The default value is 8. 2032 2033config EFI_RUNTIME_MAP 2034 bool "Export EFI runtime maps to sysfs" if EXPERT 2035 depends on EFI 2036 default KEXEC_CORE 2037 help 2038 Export EFI runtime memory regions to /sys/firmware/efi/runtime-map. 2039 That memory map is required by the 2nd kernel to set up EFI virtual 2040 mappings after kexec, but can also be used for debugging purposes. 2041 2042 See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map. 2043 2044source "kernel/Kconfig.hz" 2045 2046config KEXEC 2047 bool "kexec system call" 2048 select KEXEC_CORE 2049 help 2050 kexec is a system call that implements the ability to shutdown your 2051 current kernel, and to start another kernel. It is like a reboot 2052 but it is independent of the system firmware. And like a reboot 2053 you can start any kernel with it, not just Linux. 2054 2055 The name comes from the similarity to the exec system call. 2056 2057 It is an ongoing process to be certain the hardware in a machine 2058 is properly shutdown, so do not be surprised if this code does not 2059 initially work for you. As of this writing the exact hardware 2060 interface is strongly in flux, so no good recommendation can be 2061 made. 2062 2063config KEXEC_FILE 2064 bool "kexec file based system call" 2065 select KEXEC_CORE 2066 select HAVE_IMA_KEXEC if IMA 2067 depends on X86_64 2068 depends on CRYPTO=y 2069 depends on CRYPTO_SHA256=y 2070 help 2071 This is new version of kexec system call. This system call is 2072 file based and takes file descriptors as system call argument 2073 for kernel and initramfs as opposed to list of segments as 2074 accepted by previous system call. 2075 2076config ARCH_HAS_KEXEC_PURGATORY 2077 def_bool KEXEC_FILE 2078 2079config KEXEC_SIG 2080 bool "Verify kernel signature during kexec_file_load() syscall" 2081 depends on KEXEC_FILE 2082 help 2083 2084 This option makes the kexec_file_load() syscall check for a valid 2085 signature of the kernel image. The image can still be loaded without 2086 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2087 there's a signature that we can check, then it must be valid. 2088 2089 In addition to this option, you need to enable signature 2090 verification for the corresponding kernel image type being 2091 loaded in order for this to work. 2092 2093config KEXEC_SIG_FORCE 2094 bool "Require a valid signature in kexec_file_load() syscall" 2095 depends on KEXEC_SIG 2096 help 2097 This option makes kernel signature verification mandatory for 2098 the kexec_file_load() syscall. 2099 2100config KEXEC_BZIMAGE_VERIFY_SIG 2101 bool "Enable bzImage signature verification support" 2102 depends on KEXEC_SIG 2103 depends on SIGNED_PE_FILE_VERIFICATION 2104 select SYSTEM_TRUSTED_KEYRING 2105 help 2106 Enable bzImage signature verification support. 2107 2108config CRASH_DUMP 2109 bool "kernel crash dumps" 2110 depends on X86_64 || (X86_32 && HIGHMEM) 2111 help 2112 Generate crash dump after being started by kexec. 2113 This should be normally only set in special crash dump kernels 2114 which are loaded in the main kernel with kexec-tools into 2115 a specially reserved region and then later executed after 2116 a crash by kdump/kexec. The crash dump kernel must be compiled 2117 to a memory address not used by the main kernel or BIOS using 2118 PHYSICAL_START, or it must be built as a relocatable image 2119 (CONFIG_RELOCATABLE=y). 2120 For more details see Documentation/admin-guide/kdump/kdump.rst 2121 2122config KEXEC_JUMP 2123 bool "kexec jump" 2124 depends on KEXEC && HIBERNATION 2125 help 2126 Jump between original kernel and kexeced kernel and invoke 2127 code in physical address mode via KEXEC 2128 2129config PHYSICAL_START 2130 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2131 default "0x1000000" 2132 help 2133 This gives the physical address where the kernel is loaded. 2134 2135 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2136 bzImage will decompress itself to above physical address and 2137 run from there. Otherwise, bzImage will run from the address where 2138 it has been loaded by the boot loader and will ignore above physical 2139 address. 2140 2141 In normal kdump cases one does not have to set/change this option 2142 as now bzImage can be compiled as a completely relocatable image 2143 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2144 address. This option is mainly useful for the folks who don't want 2145 to use a bzImage for capturing the crash dump and want to use a 2146 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2147 to be specifically compiled to run from a specific memory area 2148 (normally a reserved region) and this option comes handy. 2149 2150 So if you are using bzImage for capturing the crash dump, 2151 leave the value here unchanged to 0x1000000 and set 2152 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2153 for capturing the crash dump change this value to start of 2154 the reserved region. In other words, it can be set based on 2155 the "X" value as specified in the "crashkernel=YM@XM" 2156 command line boot parameter passed to the panic-ed 2157 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2158 for more details about crash dumps. 2159 2160 Usage of bzImage for capturing the crash dump is recommended as 2161 one does not have to build two kernels. Same kernel can be used 2162 as production kernel and capture kernel. Above option should have 2163 gone away after relocatable bzImage support is introduced. But it 2164 is present because there are users out there who continue to use 2165 vmlinux for dump capture. This option should go away down the 2166 line. 2167 2168 Don't change this unless you know what you are doing. 2169 2170config RELOCATABLE 2171 bool "Build a relocatable kernel" 2172 default y 2173 help 2174 This builds a kernel image that retains relocation information 2175 so it can be loaded someplace besides the default 1MB. 2176 The relocations tend to make the kernel binary about 10% larger, 2177 but are discarded at runtime. 2178 2179 One use is for the kexec on panic case where the recovery kernel 2180 must live at a different physical address than the primary 2181 kernel. 2182 2183 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2184 it has been loaded at and the compile time physical address 2185 (CONFIG_PHYSICAL_START) is used as the minimum location. 2186 2187config RANDOMIZE_BASE 2188 bool "Randomize the address of the kernel image (KASLR)" 2189 depends on RELOCATABLE 2190 default y 2191 help 2192 In support of Kernel Address Space Layout Randomization (KASLR), 2193 this randomizes the physical address at which the kernel image 2194 is decompressed and the virtual address where the kernel 2195 image is mapped, as a security feature that deters exploit 2196 attempts relying on knowledge of the location of kernel 2197 code internals. 2198 2199 On 64-bit, the kernel physical and virtual addresses are 2200 randomized separately. The physical address will be anywhere 2201 between 16MB and the top of physical memory (up to 64TB). The 2202 virtual address will be randomized from 16MB up to 1GB (9 bits 2203 of entropy). Note that this also reduces the memory space 2204 available to kernel modules from 1.5GB to 1GB. 2205 2206 On 32-bit, the kernel physical and virtual addresses are 2207 randomized together. They will be randomized from 16MB up to 2208 512MB (8 bits of entropy). 2209 2210 Entropy is generated using the RDRAND instruction if it is 2211 supported. If RDTSC is supported, its value is mixed into 2212 the entropy pool as well. If neither RDRAND nor RDTSC are 2213 supported, then entropy is read from the i8254 timer. The 2214 usable entropy is limited by the kernel being built using 2215 2GB addressing, and that PHYSICAL_ALIGN must be at a 2216 minimum of 2MB. As a result, only 10 bits of entropy are 2217 theoretically possible, but the implementations are further 2218 limited due to memory layouts. 2219 2220 If unsure, say Y. 2221 2222# Relocation on x86 needs some additional build support 2223config X86_NEED_RELOCS 2224 def_bool y 2225 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2226 2227config PHYSICAL_ALIGN 2228 hex "Alignment value to which kernel should be aligned" 2229 default "0x200000" 2230 range 0x2000 0x1000000 if X86_32 2231 range 0x200000 0x1000000 if X86_64 2232 help 2233 This value puts the alignment restrictions on physical address 2234 where kernel is loaded and run from. Kernel is compiled for an 2235 address which meets above alignment restriction. 2236 2237 If bootloader loads the kernel at a non-aligned address and 2238 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2239 address aligned to above value and run from there. 2240 2241 If bootloader loads the kernel at a non-aligned address and 2242 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2243 load address and decompress itself to the address it has been 2244 compiled for and run from there. The address for which kernel is 2245 compiled already meets above alignment restrictions. Hence the 2246 end result is that kernel runs from a physical address meeting 2247 above alignment restrictions. 2248 2249 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2250 this value must be a multiple of 0x200000. 2251 2252 Don't change this unless you know what you are doing. 2253 2254config DYNAMIC_MEMORY_LAYOUT 2255 bool 2256 help 2257 This option makes base addresses of vmalloc and vmemmap as well as 2258 __PAGE_OFFSET movable during boot. 2259 2260config RANDOMIZE_MEMORY 2261 bool "Randomize the kernel memory sections" 2262 depends on X86_64 2263 depends on RANDOMIZE_BASE 2264 select DYNAMIC_MEMORY_LAYOUT 2265 default RANDOMIZE_BASE 2266 help 2267 Randomizes the base virtual address of kernel memory sections 2268 (physical memory mapping, vmalloc & vmemmap). This security feature 2269 makes exploits relying on predictable memory locations less reliable. 2270 2271 The order of allocations remains unchanged. Entropy is generated in 2272 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2273 configuration have in average 30,000 different possible virtual 2274 addresses for each memory section. 2275 2276 If unsure, say Y. 2277 2278config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2279 hex "Physical memory mapping padding" if EXPERT 2280 depends on RANDOMIZE_MEMORY 2281 default "0xa" if MEMORY_HOTPLUG 2282 default "0x0" 2283 range 0x1 0x40 if MEMORY_HOTPLUG 2284 range 0x0 0x40 2285 help 2286 Define the padding in terabytes added to the existing physical 2287 memory size during kernel memory randomization. It is useful 2288 for memory hotplug support but reduces the entropy available for 2289 address randomization. 2290 2291 If unsure, leave at the default value. 2292 2293config HOTPLUG_CPU 2294 def_bool y 2295 depends on SMP 2296 2297config BOOTPARAM_HOTPLUG_CPU0 2298 bool "Set default setting of cpu0_hotpluggable" 2299 depends on HOTPLUG_CPU 2300 help 2301 Set whether default state of cpu0_hotpluggable is on or off. 2302 2303 Say Y here to enable CPU0 hotplug by default. If this switch 2304 is turned on, there is no need to give cpu0_hotplug kernel 2305 parameter and the CPU0 hotplug feature is enabled by default. 2306 2307 Please note: there are two known CPU0 dependencies if you want 2308 to enable the CPU0 hotplug feature either by this switch or by 2309 cpu0_hotplug kernel parameter. 2310 2311 First, resume from hibernate or suspend always starts from CPU0. 2312 So hibernate and suspend are prevented if CPU0 is offline. 2313 2314 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2315 offline if any interrupt can not migrate out of CPU0. There may 2316 be other CPU0 dependencies. 2317 2318 Please make sure the dependencies are under your control before 2319 you enable this feature. 2320 2321 Say N if you don't want to enable CPU0 hotplug feature by default. 2322 You still can enable the CPU0 hotplug feature at boot by kernel 2323 parameter cpu0_hotplug. 2324 2325config DEBUG_HOTPLUG_CPU0 2326 def_bool n 2327 prompt "Debug CPU0 hotplug" 2328 depends on HOTPLUG_CPU 2329 help 2330 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2331 soon as possible and boots up userspace with CPU0 offlined. User 2332 can online CPU0 back after boot time. 2333 2334 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2335 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2336 compilation or giving cpu0_hotplug kernel parameter at boot. 2337 2338 If unsure, say N. 2339 2340config COMPAT_VDSO 2341 def_bool n 2342 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2343 depends on COMPAT_32 2344 help 2345 Certain buggy versions of glibc will crash if they are 2346 presented with a 32-bit vDSO that is not mapped at the address 2347 indicated in its segment table. 2348 2349 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2350 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2351 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2352 the only released version with the bug, but OpenSUSE 9 2353 contains a buggy "glibc 2.3.2". 2354 2355 The symptom of the bug is that everything crashes on startup, saying: 2356 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2357 2358 Saying Y here changes the default value of the vdso32 boot 2359 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2360 This works around the glibc bug but hurts performance. 2361 2362 If unsure, say N: if you are compiling your own kernel, you 2363 are unlikely to be using a buggy version of glibc. 2364 2365choice 2366 prompt "vsyscall table for legacy applications" 2367 depends on X86_64 2368 default LEGACY_VSYSCALL_XONLY 2369 help 2370 Legacy user code that does not know how to find the vDSO expects 2371 to be able to issue three syscalls by calling fixed addresses in 2372 kernel space. Since this location is not randomized with ASLR, 2373 it can be used to assist security vulnerability exploitation. 2374 2375 This setting can be changed at boot time via the kernel command 2376 line parameter vsyscall=[emulate|xonly|none]. Emulate mode 2377 is deprecated and can only be enabled using the kernel command 2378 line. 2379 2380 On a system with recent enough glibc (2.14 or newer) and no 2381 static binaries, you can say None without a performance penalty 2382 to improve security. 2383 2384 If unsure, select "Emulate execution only". 2385 2386 config LEGACY_VSYSCALL_XONLY 2387 bool "Emulate execution only" 2388 help 2389 The kernel traps and emulates calls into the fixed vsyscall 2390 address mapping and does not allow reads. This 2391 configuration is recommended when userspace might use the 2392 legacy vsyscall area but support for legacy binary 2393 instrumentation of legacy code is not needed. It mitigates 2394 certain uses of the vsyscall area as an ASLR-bypassing 2395 buffer. 2396 2397 config LEGACY_VSYSCALL_NONE 2398 bool "None" 2399 help 2400 There will be no vsyscall mapping at all. This will 2401 eliminate any risk of ASLR bypass due to the vsyscall 2402 fixed address mapping. Attempts to use the vsyscalls 2403 will be reported to dmesg, so that either old or 2404 malicious userspace programs can be identified. 2405 2406endchoice 2407 2408config CMDLINE_BOOL 2409 bool "Built-in kernel command line" 2410 help 2411 Allow for specifying boot arguments to the kernel at 2412 build time. On some systems (e.g. embedded ones), it is 2413 necessary or convenient to provide some or all of the 2414 kernel boot arguments with the kernel itself (that is, 2415 to not rely on the boot loader to provide them.) 2416 2417 To compile command line arguments into the kernel, 2418 set this option to 'Y', then fill in the 2419 boot arguments in CONFIG_CMDLINE. 2420 2421 Systems with fully functional boot loaders (i.e. non-embedded) 2422 should leave this option set to 'N'. 2423 2424config CMDLINE 2425 string "Built-in kernel command string" 2426 depends on CMDLINE_BOOL 2427 default "" 2428 help 2429 Enter arguments here that should be compiled into the kernel 2430 image and used at boot time. If the boot loader provides a 2431 command line at boot time, it is appended to this string to 2432 form the full kernel command line, when the system boots. 2433 2434 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2435 change this behavior. 2436 2437 In most cases, the command line (whether built-in or provided 2438 by the boot loader) should specify the device for the root 2439 file system. 2440 2441config CMDLINE_OVERRIDE 2442 bool "Built-in command line overrides boot loader arguments" 2443 depends on CMDLINE_BOOL && CMDLINE != "" 2444 help 2445 Set this option to 'Y' to have the kernel ignore the boot loader 2446 command line, and use ONLY the built-in command line. 2447 2448 This is used to work around broken boot loaders. This should 2449 be set to 'N' under normal conditions. 2450 2451config MODIFY_LDT_SYSCALL 2452 bool "Enable the LDT (local descriptor table)" if EXPERT 2453 default y 2454 help 2455 Linux can allow user programs to install a per-process x86 2456 Local Descriptor Table (LDT) using the modify_ldt(2) system 2457 call. This is required to run 16-bit or segmented code such as 2458 DOSEMU or some Wine programs. It is also used by some very old 2459 threading libraries. 2460 2461 Enabling this feature adds a small amount of overhead to 2462 context switches and increases the low-level kernel attack 2463 surface. Disabling it removes the modify_ldt(2) system call. 2464 2465 Saying 'N' here may make sense for embedded or server kernels. 2466 2467config STRICT_SIGALTSTACK_SIZE 2468 bool "Enforce strict size checking for sigaltstack" 2469 depends on DYNAMIC_SIGFRAME 2470 help 2471 For historical reasons MINSIGSTKSZ is a constant which became 2472 already too small with AVX512 support. Add a mechanism to 2473 enforce strict checking of the sigaltstack size against the 2474 real size of the FPU frame. This option enables the check 2475 by default. It can also be controlled via the kernel command 2476 line option 'strict_sas_size' independent of this config 2477 switch. Enabling it might break existing applications which 2478 allocate a too small sigaltstack but 'work' because they 2479 never get a signal delivered. 2480 2481 Say 'N' unless you want to really enforce this check. 2482 2483source "kernel/livepatch/Kconfig" 2484 2485endmenu 2486 2487config CC_HAS_SLS 2488 def_bool $(cc-option,-mharden-sls=all) 2489 2490config CC_HAS_RETURN_THUNK 2491 def_bool $(cc-option,-mfunction-return=thunk-extern) 2492 2493config CC_HAS_ENTRY_PADDING 2494 def_bool $(cc-option,-fpatchable-function-entry=16,16) 2495 2496config FUNCTION_PADDING_CFI 2497 int 2498 default 59 if FUNCTION_ALIGNMENT_64B 2499 default 27 if FUNCTION_ALIGNMENT_32B 2500 default 11 if FUNCTION_ALIGNMENT_16B 2501 default 3 if FUNCTION_ALIGNMENT_8B 2502 default 0 2503 2504# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG 2505# except Kconfig can't do arithmetic :/ 2506config FUNCTION_PADDING_BYTES 2507 int 2508 default FUNCTION_PADDING_CFI if CFI_CLANG 2509 default FUNCTION_ALIGNMENT 2510 2511config CALL_PADDING 2512 def_bool n 2513 depends on CC_HAS_ENTRY_PADDING && OBJTOOL 2514 select FUNCTION_ALIGNMENT_16B 2515 2516config FINEIBT 2517 def_bool y 2518 depends on X86_KERNEL_IBT && CFI_CLANG && RETPOLINE 2519 select CALL_PADDING 2520 2521config HAVE_CALL_THUNKS 2522 def_bool y 2523 depends on CC_HAS_ENTRY_PADDING && RETHUNK && OBJTOOL 2524 2525config CALL_THUNKS 2526 def_bool n 2527 select CALL_PADDING 2528 2529config PREFIX_SYMBOLS 2530 def_bool y 2531 depends on CALL_PADDING && !CFI_CLANG 2532 2533menuconfig SPECULATION_MITIGATIONS 2534 bool "Mitigations for speculative execution vulnerabilities" 2535 default y 2536 help 2537 Say Y here to enable options which enable mitigations for 2538 speculative execution hardware vulnerabilities. 2539 2540 If you say N, all mitigations will be disabled. You really 2541 should know what you are doing to say so. 2542 2543if SPECULATION_MITIGATIONS 2544 2545config PAGE_TABLE_ISOLATION 2546 bool "Remove the kernel mapping in user mode" 2547 default y 2548 depends on (X86_64 || X86_PAE) 2549 help 2550 This feature reduces the number of hardware side channels by 2551 ensuring that the majority of kernel addresses are not mapped 2552 into userspace. 2553 2554 See Documentation/x86/pti.rst for more details. 2555 2556config RETPOLINE 2557 bool "Avoid speculative indirect branches in kernel" 2558 select OBJTOOL if HAVE_OBJTOOL 2559 default y 2560 help 2561 Compile kernel with the retpoline compiler options to guard against 2562 kernel-to-user data leaks by avoiding speculative indirect 2563 branches. Requires a compiler with -mindirect-branch=thunk-extern 2564 support for full protection. The kernel may run slower. 2565 2566config RETHUNK 2567 bool "Enable return-thunks" 2568 depends on RETPOLINE && CC_HAS_RETURN_THUNK 2569 select OBJTOOL if HAVE_OBJTOOL 2570 default y if X86_64 2571 help 2572 Compile the kernel with the return-thunks compiler option to guard 2573 against kernel-to-user data leaks by avoiding return speculation. 2574 Requires a compiler with -mfunction-return=thunk-extern 2575 support for full protection. The kernel may run slower. 2576 2577config CPU_UNRET_ENTRY 2578 bool "Enable UNRET on kernel entry" 2579 depends on CPU_SUP_AMD && RETHUNK && X86_64 2580 default y 2581 help 2582 Compile the kernel with support for the retbleed=unret mitigation. 2583 2584config CALL_DEPTH_TRACKING 2585 bool "Mitigate RSB underflow with call depth tracking" 2586 depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS 2587 select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 2588 select CALL_THUNKS 2589 default y 2590 help 2591 Compile the kernel with call depth tracking to mitigate the Intel 2592 SKL Return-Speculation-Buffer (RSB) underflow issue. The 2593 mitigation is off by default and needs to be enabled on the 2594 kernel command line via the retbleed=stuff option. For 2595 non-affected systems the overhead of this option is marginal as 2596 the call depth tracking is using run-time generated call thunks 2597 in a compiler generated padding area and call patching. This 2598 increases text size by ~5%. For non affected systems this space 2599 is unused. On affected SKL systems this results in a significant 2600 performance gain over the IBRS mitigation. 2601 2602config CALL_THUNKS_DEBUG 2603 bool "Enable call thunks and call depth tracking debugging" 2604 depends on CALL_DEPTH_TRACKING 2605 select FUNCTION_ALIGNMENT_32B 2606 default n 2607 help 2608 Enable call/ret counters for imbalance detection and build in 2609 a noisy dmesg about callthunks generation and call patching for 2610 trouble shooting. The debug prints need to be enabled on the 2611 kernel command line with 'debug-callthunks'. 2612 Only enable this, when you are debugging call thunks as this 2613 creates a noticable runtime overhead. If unsure say N. 2614 2615config CPU_IBPB_ENTRY 2616 bool "Enable IBPB on kernel entry" 2617 depends on CPU_SUP_AMD && X86_64 2618 default y 2619 help 2620 Compile the kernel with support for the retbleed=ibpb mitigation. 2621 2622config CPU_IBRS_ENTRY 2623 bool "Enable IBRS on kernel entry" 2624 depends on CPU_SUP_INTEL && X86_64 2625 default y 2626 help 2627 Compile the kernel with support for the spectre_v2=ibrs mitigation. 2628 This mitigates both spectre_v2 and retbleed at great cost to 2629 performance. 2630 2631config SLS 2632 bool "Mitigate Straight-Line-Speculation" 2633 depends on CC_HAS_SLS && X86_64 2634 select OBJTOOL if HAVE_OBJTOOL 2635 default n 2636 help 2637 Compile the kernel with straight-line-speculation options to guard 2638 against straight line speculation. The kernel image might be slightly 2639 larger. 2640 2641endif 2642 2643config ARCH_HAS_ADD_PAGES 2644 def_bool y 2645 depends on ARCH_ENABLE_MEMORY_HOTPLUG 2646 2647config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 2648 def_bool y 2649 2650menu "Power management and ACPI options" 2651 2652config ARCH_HIBERNATION_HEADER 2653 def_bool y 2654 depends on HIBERNATION 2655 2656source "kernel/power/Kconfig" 2657 2658source "drivers/acpi/Kconfig" 2659 2660config X86_APM_BOOT 2661 def_bool y 2662 depends on APM 2663 2664menuconfig APM 2665 tristate "APM (Advanced Power Management) BIOS support" 2666 depends on X86_32 && PM_SLEEP 2667 help 2668 APM is a BIOS specification for saving power using several different 2669 techniques. This is mostly useful for battery powered laptops with 2670 APM compliant BIOSes. If you say Y here, the system time will be 2671 reset after a RESUME operation, the /proc/apm device will provide 2672 battery status information, and user-space programs will receive 2673 notification of APM "events" (e.g. battery status change). 2674 2675 If you select "Y" here, you can disable actual use of the APM 2676 BIOS by passing the "apm=off" option to the kernel at boot time. 2677 2678 Note that the APM support is almost completely disabled for 2679 machines with more than one CPU. 2680 2681 In order to use APM, you will need supporting software. For location 2682 and more information, read <file:Documentation/power/apm-acpi.rst> 2683 and the Battery Powered Linux mini-HOWTO, available from 2684 <http://www.tldp.org/docs.html#howto>. 2685 2686 This driver does not spin down disk drives (see the hdparm(8) 2687 manpage ("man 8 hdparm") for that), and it doesn't turn off 2688 VESA-compliant "green" monitors. 2689 2690 This driver does not support the TI 4000M TravelMate and the ACER 2691 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2692 desktop machines also don't have compliant BIOSes, and this driver 2693 may cause those machines to panic during the boot phase. 2694 2695 Generally, if you don't have a battery in your machine, there isn't 2696 much point in using this driver and you should say N. If you get 2697 random kernel OOPSes or reboots that don't seem to be related to 2698 anything, try disabling/enabling this option (or disabling/enabling 2699 APM in your BIOS). 2700 2701 Some other things you should try when experiencing seemingly random, 2702 "weird" problems: 2703 2704 1) make sure that you have enough swap space and that it is 2705 enabled. 2706 2) pass the "idle=poll" option to the kernel 2707 3) switch on floating point emulation in the kernel and pass 2708 the "no387" option to the kernel 2709 4) pass the "floppy=nodma" option to the kernel 2710 5) pass the "mem=4M" option to the kernel (thereby disabling 2711 all but the first 4 MB of RAM) 2712 6) make sure that the CPU is not over clocked. 2713 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2714 8) disable the cache from your BIOS settings 2715 9) install a fan for the video card or exchange video RAM 2716 10) install a better fan for the CPU 2717 11) exchange RAM chips 2718 12) exchange the motherboard. 2719 2720 To compile this driver as a module, choose M here: the 2721 module will be called apm. 2722 2723if APM 2724 2725config APM_IGNORE_USER_SUSPEND 2726 bool "Ignore USER SUSPEND" 2727 help 2728 This option will ignore USER SUSPEND requests. On machines with a 2729 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2730 series notebooks, it is necessary to say Y because of a BIOS bug. 2731 2732config APM_DO_ENABLE 2733 bool "Enable PM at boot time" 2734 help 2735 Enable APM features at boot time. From page 36 of the APM BIOS 2736 specification: "When disabled, the APM BIOS does not automatically 2737 power manage devices, enter the Standby State, enter the Suspend 2738 State, or take power saving steps in response to CPU Idle calls." 2739 This driver will make CPU Idle calls when Linux is idle (unless this 2740 feature is turned off -- see "Do CPU IDLE calls", below). This 2741 should always save battery power, but more complicated APM features 2742 will be dependent on your BIOS implementation. You may need to turn 2743 this option off if your computer hangs at boot time when using APM 2744 support, or if it beeps continuously instead of suspending. Turn 2745 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2746 T400CDT. This is off by default since most machines do fine without 2747 this feature. 2748 2749config APM_CPU_IDLE 2750 depends on CPU_IDLE 2751 bool "Make CPU Idle calls when idle" 2752 help 2753 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2754 On some machines, this can activate improved power savings, such as 2755 a slowed CPU clock rate, when the machine is idle. These idle calls 2756 are made after the idle loop has run for some length of time (e.g., 2757 333 mS). On some machines, this will cause a hang at boot time or 2758 whenever the CPU becomes idle. (On machines with more than one CPU, 2759 this option does nothing.) 2760 2761config APM_DISPLAY_BLANK 2762 bool "Enable console blanking using APM" 2763 help 2764 Enable console blanking using the APM. Some laptops can use this to 2765 turn off the LCD backlight when the screen blanker of the Linux 2766 virtual console blanks the screen. Note that this is only used by 2767 the virtual console screen blanker, and won't turn off the backlight 2768 when using the X Window system. This also doesn't have anything to 2769 do with your VESA-compliant power-saving monitor. Further, this 2770 option doesn't work for all laptops -- it might not turn off your 2771 backlight at all, or it might print a lot of errors to the console, 2772 especially if you are using gpm. 2773 2774config APM_ALLOW_INTS 2775 bool "Allow interrupts during APM BIOS calls" 2776 help 2777 Normally we disable external interrupts while we are making calls to 2778 the APM BIOS as a measure to lessen the effects of a badly behaving 2779 BIOS implementation. The BIOS should reenable interrupts if it 2780 needs to. Unfortunately, some BIOSes do not -- especially those in 2781 many of the newer IBM Thinkpads. If you experience hangs when you 2782 suspend, try setting this to Y. Otherwise, say N. 2783 2784endif # APM 2785 2786source "drivers/cpufreq/Kconfig" 2787 2788source "drivers/cpuidle/Kconfig" 2789 2790source "drivers/idle/Kconfig" 2791 2792endmenu 2793 2794menu "Bus options (PCI etc.)" 2795 2796choice 2797 prompt "PCI access mode" 2798 depends on X86_32 && PCI 2799 default PCI_GOANY 2800 help 2801 On PCI systems, the BIOS can be used to detect the PCI devices and 2802 determine their configuration. However, some old PCI motherboards 2803 have BIOS bugs and may crash if this is done. Also, some embedded 2804 PCI-based systems don't have any BIOS at all. Linux can also try to 2805 detect the PCI hardware directly without using the BIOS. 2806 2807 With this option, you can specify how Linux should detect the 2808 PCI devices. If you choose "BIOS", the BIOS will be used, 2809 if you choose "Direct", the BIOS won't be used, and if you 2810 choose "MMConfig", then PCI Express MMCONFIG will be used. 2811 If you choose "Any", the kernel will try MMCONFIG, then the 2812 direct access method and falls back to the BIOS if that doesn't 2813 work. If unsure, go with the default, which is "Any". 2814 2815config PCI_GOBIOS 2816 bool "BIOS" 2817 2818config PCI_GOMMCONFIG 2819 bool "MMConfig" 2820 2821config PCI_GODIRECT 2822 bool "Direct" 2823 2824config PCI_GOOLPC 2825 bool "OLPC XO-1" 2826 depends on OLPC 2827 2828config PCI_GOANY 2829 bool "Any" 2830 2831endchoice 2832 2833config PCI_BIOS 2834 def_bool y 2835 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2836 2837# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2838config PCI_DIRECT 2839 def_bool y 2840 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2841 2842config PCI_MMCONFIG 2843 bool "Support mmconfig PCI config space access" if X86_64 2844 default y 2845 depends on PCI && (ACPI || JAILHOUSE_GUEST) 2846 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2847 2848config PCI_OLPC 2849 def_bool y 2850 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2851 2852config PCI_XEN 2853 def_bool y 2854 depends on PCI && XEN 2855 2856config MMCONF_FAM10H 2857 def_bool y 2858 depends on X86_64 && PCI_MMCONFIG && ACPI 2859 2860config PCI_CNB20LE_QUIRK 2861 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2862 depends on PCI 2863 help 2864 Read the PCI windows out of the CNB20LE host bridge. This allows 2865 PCI hotplug to work on systems with the CNB20LE chipset which do 2866 not have ACPI. 2867 2868 There's no public spec for this chipset, and this functionality 2869 is known to be incomplete. 2870 2871 You should say N unless you know you need this. 2872 2873config ISA_BUS 2874 bool "ISA bus support on modern systems" if EXPERT 2875 help 2876 Expose ISA bus device drivers and options available for selection and 2877 configuration. Enable this option if your target machine has an ISA 2878 bus. ISA is an older system, displaced by PCI and newer bus 2879 architectures -- if your target machine is modern, it probably does 2880 not have an ISA bus. 2881 2882 If unsure, say N. 2883 2884# x86_64 have no ISA slots, but can have ISA-style DMA. 2885config ISA_DMA_API 2886 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2887 default y 2888 help 2889 Enables ISA-style DMA support for devices requiring such controllers. 2890 If unsure, say Y. 2891 2892if X86_32 2893 2894config ISA 2895 bool "ISA support" 2896 help 2897 Find out whether you have ISA slots on your motherboard. ISA is the 2898 name of a bus system, i.e. the way the CPU talks to the other stuff 2899 inside your box. Other bus systems are PCI, EISA, MicroChannel 2900 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2901 newer boards don't support it. If you have ISA, say Y, otherwise N. 2902 2903config SCx200 2904 tristate "NatSemi SCx200 support" 2905 help 2906 This provides basic support for National Semiconductor's 2907 (now AMD's) Geode processors. The driver probes for the 2908 PCI-IDs of several on-chip devices, so its a good dependency 2909 for other scx200_* drivers. 2910 2911 If compiled as a module, the driver is named scx200. 2912 2913config SCx200HR_TIMER 2914 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2915 depends on SCx200 2916 default y 2917 help 2918 This driver provides a clocksource built upon the on-chip 2919 27MHz high-resolution timer. Its also a workaround for 2920 NSC Geode SC-1100's buggy TSC, which loses time when the 2921 processor goes idle (as is done by the scheduler). The 2922 other workaround is idle=poll boot option. 2923 2924config OLPC 2925 bool "One Laptop Per Child support" 2926 depends on !X86_PAE 2927 select GPIOLIB 2928 select OF 2929 select OF_PROMTREE 2930 select IRQ_DOMAIN 2931 select OLPC_EC 2932 help 2933 Add support for detecting the unique features of the OLPC 2934 XO hardware. 2935 2936config OLPC_XO1_PM 2937 bool "OLPC XO-1 Power Management" 2938 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2939 help 2940 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2941 2942config OLPC_XO1_RTC 2943 bool "OLPC XO-1 Real Time Clock" 2944 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2945 help 2946 Add support for the XO-1 real time clock, which can be used as a 2947 programmable wakeup source. 2948 2949config OLPC_XO1_SCI 2950 bool "OLPC XO-1 SCI extras" 2951 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2952 depends on INPUT=y 2953 select POWER_SUPPLY 2954 help 2955 Add support for SCI-based features of the OLPC XO-1 laptop: 2956 - EC-driven system wakeups 2957 - Power button 2958 - Ebook switch 2959 - Lid switch 2960 - AC adapter status updates 2961 - Battery status updates 2962 2963config OLPC_XO15_SCI 2964 bool "OLPC XO-1.5 SCI extras" 2965 depends on OLPC && ACPI 2966 select POWER_SUPPLY 2967 help 2968 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2969 - EC-driven system wakeups 2970 - AC adapter status updates 2971 - Battery status updates 2972 2973config ALIX 2974 bool "PCEngines ALIX System Support (LED setup)" 2975 select GPIOLIB 2976 help 2977 This option enables system support for the PCEngines ALIX. 2978 At present this just sets up LEDs for GPIO control on 2979 ALIX2/3/6 boards. However, other system specific setup should 2980 get added here. 2981 2982 Note: You must still enable the drivers for GPIO and LED support 2983 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2984 2985 Note: You have to set alix.force=1 for boards with Award BIOS. 2986 2987config NET5501 2988 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2989 select GPIOLIB 2990 help 2991 This option enables system support for the Soekris Engineering net5501. 2992 2993config GEOS 2994 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2995 select GPIOLIB 2996 depends on DMI 2997 help 2998 This option enables system support for the Traverse Technologies GEOS. 2999 3000config TS5500 3001 bool "Technologic Systems TS-5500 platform support" 3002 depends on MELAN 3003 select CHECK_SIGNATURE 3004 select NEW_LEDS 3005 select LEDS_CLASS 3006 help 3007 This option enables system support for the Technologic Systems TS-5500. 3008 3009endif # X86_32 3010 3011config AMD_NB 3012 def_bool y 3013 depends on CPU_SUP_AMD && PCI 3014 3015endmenu 3016 3017menu "Binary Emulations" 3018 3019config IA32_EMULATION 3020 bool "IA32 Emulation" 3021 depends on X86_64 3022 select ARCH_WANT_OLD_COMPAT_IPC 3023 select BINFMT_ELF 3024 select COMPAT_OLD_SIGACTION 3025 help 3026 Include code to run legacy 32-bit programs under a 3027 64-bit kernel. You should likely turn this on, unless you're 3028 100% sure that you don't have any 32-bit programs left. 3029 3030config X86_X32_ABI 3031 bool "x32 ABI for 64-bit mode" 3032 depends on X86_64 3033 # llvm-objcopy does not convert x86_64 .note.gnu.property or 3034 # compressed debug sections to x86_x32 properly: 3035 # https://github.com/ClangBuiltLinux/linux/issues/514 3036 # https://github.com/ClangBuiltLinux/linux/issues/1141 3037 depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm) 3038 help 3039 Include code to run binaries for the x32 native 32-bit ABI 3040 for 64-bit processors. An x32 process gets access to the 3041 full 64-bit register file and wide data path while leaving 3042 pointers at 32 bits for smaller memory footprint. 3043 3044config COMPAT_32 3045 def_bool y 3046 depends on IA32_EMULATION || X86_32 3047 select HAVE_UID16 3048 select OLD_SIGSUSPEND3 3049 3050config COMPAT 3051 def_bool y 3052 depends on IA32_EMULATION || X86_X32_ABI 3053 3054config COMPAT_FOR_U64_ALIGNMENT 3055 def_bool y 3056 depends on COMPAT 3057 3058endmenu 3059 3060config HAVE_ATOMIC_IOMAP 3061 def_bool y 3062 depends on X86_32 3063 3064source "arch/x86/kvm/Kconfig" 3065 3066source "arch/x86/Kconfig.assembler" 3067