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_DEBUG_VIRTUAL 73 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 74 select ARCH_HAS_DEVMEM_IS_ALLOWED 75 select ARCH_HAS_EARLY_DEBUG if KGDB 76 select ARCH_HAS_ELF_RANDOMIZE 77 select ARCH_HAS_FAST_MULTIPLIER 78 select ARCH_HAS_FILTER_PGPROT 79 select ARCH_HAS_FORTIFY_SOURCE 80 select ARCH_HAS_GCOV_PROFILE_ALL 81 select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION 82 select ARCH_HAS_MEM_ENCRYPT 83 select ARCH_HAS_MEMBARRIER_SYNC_CORE 84 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 85 select ARCH_HAS_PMEM_API if X86_64 86 select ARCH_HAS_PTE_DEVMAP if X86_64 87 select ARCH_HAS_PTE_SPECIAL 88 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 89 select ARCH_HAS_COPY_MC if X86_64 90 select ARCH_HAS_SET_MEMORY 91 select ARCH_HAS_SET_DIRECT_MAP 92 select ARCH_HAS_STRICT_KERNEL_RWX 93 select ARCH_HAS_STRICT_MODULE_RWX 94 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 95 select ARCH_HAS_SYSCALL_WRAPPER 96 select ARCH_HAS_UBSAN_SANITIZE_ALL 97 select ARCH_HAS_DEBUG_WX 98 select ARCH_HAS_ZONE_DMA_SET if EXPERT 99 select ARCH_HAVE_NMI_SAFE_CMPXCHG 100 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 101 select ARCH_MIGHT_HAVE_PC_PARPORT 102 select ARCH_MIGHT_HAVE_PC_SERIO 103 select ARCH_STACKWALK 104 select ARCH_SUPPORTS_ACPI 105 select ARCH_SUPPORTS_ATOMIC_RMW 106 select ARCH_SUPPORTS_DEBUG_PAGEALLOC 107 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 108 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 109 select ARCH_SUPPORTS_LTO_CLANG 110 select ARCH_SUPPORTS_LTO_CLANG_THIN 111 select ARCH_USE_BUILTIN_BSWAP 112 select ARCH_USE_MEMTEST 113 select ARCH_USE_QUEUED_RWLOCKS 114 select ARCH_USE_QUEUED_SPINLOCKS 115 select ARCH_USE_SYM_ANNOTATIONS 116 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 117 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 118 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 119 select ARCH_WANTS_NO_INSTR 120 select ARCH_WANT_HUGE_PMD_SHARE 121 select ARCH_WANT_LD_ORPHAN_WARN 122 select ARCH_WANTS_THP_SWAP if X86_64 123 select ARCH_HAS_PARANOID_L1D_FLUSH 124 select BUILDTIME_TABLE_SORT 125 select CLKEVT_I8253 126 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 127 select CLOCKSOURCE_WATCHDOG 128 select DCACHE_WORD_ACCESS 129 select DYNAMIC_SIGFRAME 130 select EDAC_ATOMIC_SCRUB 131 select EDAC_SUPPORT 132 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 133 select GENERIC_CLOCKEVENTS_MIN_ADJUST 134 select GENERIC_CMOS_UPDATE 135 select GENERIC_CPU_AUTOPROBE 136 select GENERIC_CPU_VULNERABILITIES 137 select GENERIC_EARLY_IOREMAP 138 select GENERIC_ENTRY 139 select GENERIC_FIND_FIRST_BIT 140 select GENERIC_IOMAP 141 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 142 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 143 select GENERIC_IRQ_MIGRATION if SMP 144 select GENERIC_IRQ_PROBE 145 select GENERIC_IRQ_RESERVATION_MODE 146 select GENERIC_IRQ_SHOW 147 select GENERIC_PENDING_IRQ if SMP 148 select GENERIC_PTDUMP 149 select GENERIC_SMP_IDLE_THREAD 150 select GENERIC_TIME_VSYSCALL 151 select GENERIC_GETTIMEOFDAY 152 select GENERIC_VDSO_TIME_NS 153 select GUP_GET_PTE_LOW_HIGH if X86_PAE 154 select HARDIRQS_SW_RESEND 155 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 156 select HAVE_ACPI_APEI if ACPI 157 select HAVE_ACPI_APEI_NMI if ACPI 158 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 159 select HAVE_ARCH_AUDITSYSCALL 160 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 161 select HAVE_ARCH_JUMP_LABEL 162 select HAVE_ARCH_JUMP_LABEL_RELATIVE 163 select HAVE_ARCH_KASAN if X86_64 164 select HAVE_ARCH_KASAN_VMALLOC if X86_64 165 select HAVE_ARCH_KFENCE 166 select HAVE_ARCH_KGDB 167 select HAVE_ARCH_MMAP_RND_BITS if MMU 168 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 169 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 170 select HAVE_ARCH_PREL32_RELOCATIONS 171 select HAVE_ARCH_SECCOMP_FILTER 172 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 173 select HAVE_ARCH_STACKLEAK 174 select HAVE_ARCH_TRACEHOOK 175 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 176 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 177 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 178 select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 179 select HAVE_ARCH_VMAP_STACK if X86_64 180 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 181 select HAVE_ARCH_WITHIN_STACK_FRAMES 182 select HAVE_ASM_MODVERSIONS 183 select HAVE_CMPXCHG_DOUBLE 184 select HAVE_CMPXCHG_LOCAL 185 select HAVE_CONTEXT_TRACKING if X86_64 186 select HAVE_CONTEXT_TRACKING_OFFSTACK if HAVE_CONTEXT_TRACKING 187 select HAVE_C_RECORDMCOUNT 188 select HAVE_OBJTOOL_MCOUNT if STACK_VALIDATION 189 select HAVE_DEBUG_KMEMLEAK 190 select HAVE_DMA_CONTIGUOUS 191 select HAVE_DYNAMIC_FTRACE 192 select HAVE_DYNAMIC_FTRACE_WITH_REGS 193 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 194 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 195 select HAVE_SAMPLE_FTRACE_DIRECT if X86_64 196 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64 197 select HAVE_EBPF_JIT 198 select HAVE_EFFICIENT_UNALIGNED_ACCESS 199 select HAVE_EISA 200 select HAVE_EXIT_THREAD 201 select HAVE_FAST_GUP 202 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 203 select HAVE_FTRACE_MCOUNT_RECORD 204 select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) 205 select HAVE_FUNCTION_TRACER 206 select HAVE_GCC_PLUGINS 207 select HAVE_HW_BREAKPOINT 208 select HAVE_IOREMAP_PROT 209 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 210 select HAVE_IRQ_TIME_ACCOUNTING 211 select HAVE_KERNEL_BZIP2 212 select HAVE_KERNEL_GZIP 213 select HAVE_KERNEL_LZ4 214 select HAVE_KERNEL_LZMA 215 select HAVE_KERNEL_LZO 216 select HAVE_KERNEL_XZ 217 select HAVE_KERNEL_ZSTD 218 select HAVE_KPROBES 219 select HAVE_KPROBES_ON_FTRACE 220 select HAVE_FUNCTION_ERROR_INJECTION 221 select HAVE_KRETPROBES 222 select HAVE_KVM 223 select HAVE_LIVEPATCH if X86_64 224 select HAVE_MIXED_BREAKPOINTS_REGS 225 select HAVE_MOD_ARCH_SPECIFIC 226 select HAVE_MOVE_PMD 227 select HAVE_MOVE_PUD 228 select HAVE_NMI 229 select HAVE_OPTPROBES 230 select HAVE_PCSPKR_PLATFORM 231 select HAVE_PERF_EVENTS 232 select HAVE_PERF_EVENTS_NMI 233 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 234 select HAVE_PCI 235 select HAVE_PERF_REGS 236 select HAVE_PERF_USER_STACK_DUMP 237 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 238 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 239 select HAVE_REGS_AND_STACK_ACCESS_API 240 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 241 select HAVE_FUNCTION_ARG_ACCESS_API 242 select HAVE_SOFTIRQ_ON_OWN_STACK 243 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 244 select HAVE_STACK_VALIDATION if X86_64 245 select HAVE_STATIC_CALL 246 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION 247 select HAVE_PREEMPT_DYNAMIC 248 select HAVE_RSEQ 249 select HAVE_SYSCALL_TRACEPOINTS 250 select HAVE_UNSTABLE_SCHED_CLOCK 251 select HAVE_USER_RETURN_NOTIFIER 252 select HAVE_GENERIC_VDSO 253 select HOTPLUG_SMT if SMP 254 select IRQ_FORCED_THREADING 255 select NEED_SG_DMA_LENGTH 256 select PCI_DOMAINS if PCI 257 select PCI_LOCKLESS_CONFIG if PCI 258 select PERF_EVENTS 259 select RTC_LIB 260 select RTC_MC146818_LIB 261 select SPARSE_IRQ 262 select SRCU 263 select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE) 264 select SYSCTL_EXCEPTION_TRACE 265 select THREAD_INFO_IN_TASK 266 select TRACE_IRQFLAGS_SUPPORT 267 select USER_STACKTRACE_SUPPORT 268 select VIRT_TO_BUS 269 select HAVE_ARCH_KCSAN if X86_64 270 select X86_FEATURE_NAMES if PROC_FS 271 select PROC_PID_ARCH_STATUS if PROC_FS 272 select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX 273 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 274 275config INSTRUCTION_DECODER 276 def_bool y 277 depends on KPROBES || PERF_EVENTS || UPROBES 278 279config OUTPUT_FORMAT 280 string 281 default "elf32-i386" if X86_32 282 default "elf64-x86-64" if X86_64 283 284config LOCKDEP_SUPPORT 285 def_bool y 286 287config STACKTRACE_SUPPORT 288 def_bool y 289 290config MMU 291 def_bool y 292 293config ARCH_MMAP_RND_BITS_MIN 294 default 28 if 64BIT 295 default 8 296 297config ARCH_MMAP_RND_BITS_MAX 298 default 32 if 64BIT 299 default 16 300 301config ARCH_MMAP_RND_COMPAT_BITS_MIN 302 default 8 303 304config ARCH_MMAP_RND_COMPAT_BITS_MAX 305 default 16 306 307config SBUS 308 bool 309 310config GENERIC_ISA_DMA 311 def_bool y 312 depends on ISA_DMA_API 313 314config GENERIC_BUG 315 def_bool y 316 depends on BUG 317 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 318 319config GENERIC_BUG_RELATIVE_POINTERS 320 bool 321 322config ARCH_MAY_HAVE_PC_FDC 323 def_bool y 324 depends on ISA_DMA_API 325 326config GENERIC_CALIBRATE_DELAY 327 def_bool y 328 329config ARCH_HAS_CPU_RELAX 330 def_bool y 331 332config ARCH_HAS_FILTER_PGPROT 333 def_bool y 334 335config HAVE_SETUP_PER_CPU_AREA 336 def_bool y 337 338config NEED_PER_CPU_EMBED_FIRST_CHUNK 339 def_bool y 340 341config NEED_PER_CPU_PAGE_FIRST_CHUNK 342 def_bool y 343 344config ARCH_HIBERNATION_POSSIBLE 345 def_bool y 346 347config ARCH_NR_GPIO 348 int 349 default 1024 if X86_64 350 default 512 351 352config ARCH_SUSPEND_POSSIBLE 353 def_bool y 354 355config ARCH_WANT_GENERAL_HUGETLB 356 def_bool y 357 358config AUDIT_ARCH 359 def_bool y if X86_64 360 361config KASAN_SHADOW_OFFSET 362 hex 363 depends on KASAN 364 default 0xdffffc0000000000 365 366config HAVE_INTEL_TXT 367 def_bool y 368 depends on INTEL_IOMMU && ACPI 369 370config X86_32_SMP 371 def_bool y 372 depends on X86_32 && SMP 373 374config X86_64_SMP 375 def_bool y 376 depends on X86_64 && SMP 377 378config ARCH_SUPPORTS_UPROBES 379 def_bool y 380 381config FIX_EARLYCON_MEM 382 def_bool y 383 384config DYNAMIC_PHYSICAL_MASK 385 bool 386 387config PGTABLE_LEVELS 388 int 389 default 5 if X86_5LEVEL 390 default 4 if X86_64 391 default 3 if X86_PAE 392 default 2 393 394config CC_HAS_SANE_STACKPROTECTOR 395 bool 396 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 397 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 398 help 399 We have to make sure stack protector is unconditionally disabled if 400 the compiler produces broken code or if it does not let us control 401 the segment on 32-bit kernels. 402 403menu "Processor type and features" 404 405config SMP 406 bool "Symmetric multi-processing support" 407 help 408 This enables support for systems with more than one CPU. If you have 409 a system with only one CPU, say N. If you have a system with more 410 than one CPU, say Y. 411 412 If you say N here, the kernel will run on uni- and multiprocessor 413 machines, but will use only one CPU of a multiprocessor machine. If 414 you say Y here, the kernel will run on many, but not all, 415 uniprocessor machines. On a uniprocessor machine, the kernel 416 will run faster if you say N here. 417 418 Note that if you say Y here and choose architecture "586" or 419 "Pentium" under "Processor family", the kernel will not work on 486 420 architectures. Similarly, multiprocessor kernels for the "PPro" 421 architecture may not work on all Pentium based boards. 422 423 People using multiprocessor machines who say Y here should also say 424 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 425 Management" code will be disabled if you say Y here. 426 427 See also <file:Documentation/x86/i386/IO-APIC.rst>, 428 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 429 <http://www.tldp.org/docs.html#howto>. 430 431 If you don't know what to do here, say N. 432 433config X86_FEATURE_NAMES 434 bool "Processor feature human-readable names" if EMBEDDED 435 default y 436 help 437 This option compiles in a table of x86 feature bits and corresponding 438 names. This is required to support /proc/cpuinfo and a few kernel 439 messages. You can disable this to save space, at the expense of 440 making those few kernel messages show numeric feature bits instead. 441 442 If in doubt, say Y. 443 444config X86_X2APIC 445 bool "Support x2apic" 446 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 447 help 448 This enables x2apic support on CPUs that have this feature. 449 450 This allows 32-bit apic IDs (so it can support very large systems), 451 and accesses the local apic via MSRs not via mmio. 452 453 If you don't know what to do here, say N. 454 455config X86_MPPARSE 456 bool "Enable MPS table" if ACPI 457 default y 458 depends on X86_LOCAL_APIC 459 help 460 For old smp systems that do not have proper acpi support. Newer systems 461 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 462 463config GOLDFISH 464 def_bool y 465 depends on X86_GOLDFISH 466 467config RETPOLINE 468 bool "Avoid speculative indirect branches in kernel" 469 default y 470 help 471 Compile kernel with the retpoline compiler options to guard against 472 kernel-to-user data leaks by avoiding speculative indirect 473 branches. Requires a compiler with -mindirect-branch=thunk-extern 474 support for full protection. The kernel may run slower. 475 476config X86_CPU_RESCTRL 477 bool "x86 CPU resource control support" 478 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 479 select KERNFS 480 select PROC_CPU_RESCTRL if PROC_FS 481 help 482 Enable x86 CPU resource control support. 483 484 Provide support for the allocation and monitoring of system resources 485 usage by the CPU. 486 487 Intel calls this Intel Resource Director Technology 488 (Intel(R) RDT). More information about RDT can be found in the 489 Intel x86 Architecture Software Developer Manual. 490 491 AMD calls this AMD Platform Quality of Service (AMD QoS). 492 More information about AMD QoS can be found in the AMD64 Technology 493 Platform Quality of Service Extensions manual. 494 495 Say N if unsure. 496 497if X86_32 498config X86_BIGSMP 499 bool "Support for big SMP systems with more than 8 CPUs" 500 depends on SMP 501 help 502 This option is needed for the systems that have more than 8 CPUs. 503 504config X86_EXTENDED_PLATFORM 505 bool "Support for extended (non-PC) x86 platforms" 506 default y 507 help 508 If you disable this option then the kernel will only support 509 standard PC platforms. (which covers the vast majority of 510 systems out there.) 511 512 If you enable this option then you'll be able to select support 513 for the following (non-PC) 32 bit x86 platforms: 514 Goldfish (Android emulator) 515 AMD Elan 516 RDC R-321x SoC 517 SGI 320/540 (Visual Workstation) 518 STA2X11-based (e.g. Northville) 519 Moorestown MID devices 520 521 If you have one of these systems, or if you want to build a 522 generic distribution kernel, say Y here - otherwise say N. 523endif 524 525if X86_64 526config X86_EXTENDED_PLATFORM 527 bool "Support for extended (non-PC) x86 platforms" 528 default y 529 help 530 If you disable this option then the kernel will only support 531 standard PC platforms. (which covers the vast majority of 532 systems out there.) 533 534 If you enable this option then you'll be able to select support 535 for the following (non-PC) 64 bit x86 platforms: 536 Numascale NumaChip 537 ScaleMP vSMP 538 SGI Ultraviolet 539 540 If you have one of these systems, or if you want to build a 541 generic distribution kernel, say Y here - otherwise say N. 542endif 543# This is an alphabetically sorted list of 64 bit extended platforms 544# Please maintain the alphabetic order if and when there are additions 545config X86_NUMACHIP 546 bool "Numascale NumaChip" 547 depends on X86_64 548 depends on X86_EXTENDED_PLATFORM 549 depends on NUMA 550 depends on SMP 551 depends on X86_X2APIC 552 depends on PCI_MMCONFIG 553 help 554 Adds support for Numascale NumaChip large-SMP systems. Needed to 555 enable more than ~168 cores. 556 If you don't have one of these, you should say N here. 557 558config X86_VSMP 559 bool "ScaleMP vSMP" 560 select HYPERVISOR_GUEST 561 select PARAVIRT 562 depends on X86_64 && PCI 563 depends on X86_EXTENDED_PLATFORM 564 depends on SMP 565 help 566 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 567 supposed to run on these EM64T-based machines. Only choose this option 568 if you have one of these machines. 569 570config X86_UV 571 bool "SGI Ultraviolet" 572 depends on X86_64 573 depends on X86_EXTENDED_PLATFORM 574 depends on NUMA 575 depends on EFI 576 depends on KEXEC_CORE 577 depends on X86_X2APIC 578 depends on PCI 579 help 580 This option is needed in order to support SGI Ultraviolet systems. 581 If you don't have one of these, you should say N here. 582 583# Following is an alphabetically sorted list of 32 bit extended platforms 584# Please maintain the alphabetic order if and when there are additions 585 586config X86_GOLDFISH 587 bool "Goldfish (Virtual Platform)" 588 depends on X86_EXTENDED_PLATFORM 589 help 590 Enable support for the Goldfish virtual platform used primarily 591 for Android development. Unless you are building for the Android 592 Goldfish emulator say N here. 593 594config X86_INTEL_CE 595 bool "CE4100 TV platform" 596 depends on PCI 597 depends on PCI_GODIRECT 598 depends on X86_IO_APIC 599 depends on X86_32 600 depends on X86_EXTENDED_PLATFORM 601 select X86_REBOOTFIXUPS 602 select OF 603 select OF_EARLY_FLATTREE 604 help 605 Select for the Intel CE media processor (CE4100) SOC. 606 This option compiles in support for the CE4100 SOC for settop 607 boxes and media devices. 608 609config X86_INTEL_MID 610 bool "Intel MID platform support" 611 depends on X86_EXTENDED_PLATFORM 612 depends on X86_PLATFORM_DEVICES 613 depends on PCI 614 depends on X86_64 || (PCI_GOANY && X86_32) 615 depends on X86_IO_APIC 616 select I2C 617 select DW_APB_TIMER 618 select INTEL_SCU_PCI 619 help 620 Select to build a kernel capable of supporting Intel MID (Mobile 621 Internet Device) platform systems which do not have the PCI legacy 622 interfaces. If you are building for a PC class system say N here. 623 624 Intel MID platforms are based on an Intel processor and chipset which 625 consume less power than most of the x86 derivatives. 626 627config X86_INTEL_QUARK 628 bool "Intel Quark platform support" 629 depends on X86_32 630 depends on X86_EXTENDED_PLATFORM 631 depends on X86_PLATFORM_DEVICES 632 depends on X86_TSC 633 depends on PCI 634 depends on PCI_GOANY 635 depends on X86_IO_APIC 636 select IOSF_MBI 637 select INTEL_IMR 638 select COMMON_CLK 639 help 640 Select to include support for Quark X1000 SoC. 641 Say Y here if you have a Quark based system such as the Arduino 642 compatible Intel Galileo. 643 644config X86_INTEL_LPSS 645 bool "Intel Low Power Subsystem Support" 646 depends on X86 && ACPI && PCI 647 select COMMON_CLK 648 select PINCTRL 649 select IOSF_MBI 650 help 651 Select to build support for Intel Low Power Subsystem such as 652 found on Intel Lynxpoint PCH. Selecting this option enables 653 things like clock tree (common clock framework) and pincontrol 654 which are needed by the LPSS peripheral drivers. 655 656config X86_AMD_PLATFORM_DEVICE 657 bool "AMD ACPI2Platform devices support" 658 depends on ACPI 659 select COMMON_CLK 660 select PINCTRL 661 help 662 Select to interpret AMD specific ACPI device to platform device 663 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 664 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 665 implemented under PINCTRL subsystem. 666 667config IOSF_MBI 668 tristate "Intel SoC IOSF Sideband support for SoC platforms" 669 depends on PCI 670 help 671 This option enables sideband register access support for Intel SoC 672 platforms. On these platforms the IOSF sideband is used in lieu of 673 MSR's for some register accesses, mostly but not limited to thermal 674 and power. Drivers may query the availability of this device to 675 determine if they need the sideband in order to work on these 676 platforms. The sideband is available on the following SoC products. 677 This list is not meant to be exclusive. 678 - BayTrail 679 - Braswell 680 - Quark 681 682 You should say Y if you are running a kernel on one of these SoC's. 683 684config IOSF_MBI_DEBUG 685 bool "Enable IOSF sideband access through debugfs" 686 depends on IOSF_MBI && DEBUG_FS 687 help 688 Select this option to expose the IOSF sideband access registers (MCR, 689 MDR, MCRX) through debugfs to write and read register information from 690 different units on the SoC. This is most useful for obtaining device 691 state information for debug and analysis. As this is a general access 692 mechanism, users of this option would have specific knowledge of the 693 device they want to access. 694 695 If you don't require the option or are in doubt, say N. 696 697config X86_RDC321X 698 bool "RDC R-321x SoC" 699 depends on X86_32 700 depends on X86_EXTENDED_PLATFORM 701 select M486 702 select X86_REBOOTFIXUPS 703 help 704 This option is needed for RDC R-321x system-on-chip, also known 705 as R-8610-(G). 706 If you don't have one of these chips, you should say N here. 707 708config X86_32_NON_STANDARD 709 bool "Support non-standard 32-bit SMP architectures" 710 depends on X86_32 && SMP 711 depends on X86_EXTENDED_PLATFORM 712 help 713 This option compiles in the bigsmp and STA2X11 default 714 subarchitectures. It is intended for a generic binary 715 kernel. If you select them all, kernel will probe it one by 716 one and will fallback to default. 717 718# Alphabetically sorted list of Non standard 32 bit platforms 719 720config X86_SUPPORTS_MEMORY_FAILURE 721 def_bool y 722 # MCE code calls memory_failure(): 723 depends on X86_MCE 724 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 725 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 726 depends on X86_64 || !SPARSEMEM 727 select ARCH_SUPPORTS_MEMORY_FAILURE 728 729config STA2X11 730 bool "STA2X11 Companion Chip Support" 731 depends on X86_32_NON_STANDARD && PCI 732 select SWIOTLB 733 select MFD_STA2X11 734 select GPIOLIB 735 help 736 This adds support for boards based on the STA2X11 IO-Hub, 737 a.k.a. "ConneXt". The chip is used in place of the standard 738 PC chipset, so all "standard" peripherals are missing. If this 739 option is selected the kernel will still be able to boot on 740 standard PC machines. 741 742config X86_32_IRIS 743 tristate "Eurobraille/Iris poweroff module" 744 depends on X86_32 745 help 746 The Iris machines from EuroBraille do not have APM or ACPI support 747 to shut themselves down properly. A special I/O sequence is 748 needed to do so, which is what this module does at 749 kernel shutdown. 750 751 This is only for Iris machines from EuroBraille. 752 753 If unused, say N. 754 755config SCHED_OMIT_FRAME_POINTER 756 def_bool y 757 prompt "Single-depth WCHAN output" 758 depends on X86 759 help 760 Calculate simpler /proc/<PID>/wchan values. If this option 761 is disabled then wchan values will recurse back to the 762 caller function. This provides more accurate wchan values, 763 at the expense of slightly more scheduling overhead. 764 765 If in doubt, say "Y". 766 767menuconfig HYPERVISOR_GUEST 768 bool "Linux guest support" 769 help 770 Say Y here to enable options for running Linux under various hyper- 771 visors. This option enables basic hypervisor detection and platform 772 setup. 773 774 If you say N, all options in this submenu will be skipped and 775 disabled, and Linux guest support won't be built in. 776 777if HYPERVISOR_GUEST 778 779config PARAVIRT 780 bool "Enable paravirtualization code" 781 depends on HAVE_STATIC_CALL 782 help 783 This changes the kernel so it can modify itself when it is run 784 under a hypervisor, potentially improving performance significantly 785 over full virtualization. However, when run without a hypervisor 786 the kernel is theoretically slower and slightly larger. 787 788config PARAVIRT_XXL 789 bool 790 791config PARAVIRT_DEBUG 792 bool "paravirt-ops debugging" 793 depends on PARAVIRT && DEBUG_KERNEL 794 help 795 Enable to debug paravirt_ops internals. Specifically, BUG if 796 a paravirt_op is missing when it is called. 797 798config PARAVIRT_SPINLOCKS 799 bool "Paravirtualization layer for spinlocks" 800 depends on PARAVIRT && SMP 801 help 802 Paravirtualized spinlocks allow a pvops backend to replace the 803 spinlock implementation with something virtualization-friendly 804 (for example, block the virtual CPU rather than spinning). 805 806 It has a minimal impact on native kernels and gives a nice performance 807 benefit on paravirtualized KVM / Xen kernels. 808 809 If you are unsure how to answer this question, answer Y. 810 811config X86_HV_CALLBACK_VECTOR 812 def_bool n 813 814source "arch/x86/xen/Kconfig" 815 816config KVM_GUEST 817 bool "KVM Guest support (including kvmclock)" 818 depends on PARAVIRT 819 select PARAVIRT_CLOCK 820 select ARCH_CPUIDLE_HALTPOLL 821 select X86_HV_CALLBACK_VECTOR 822 default y 823 help 824 This option enables various optimizations for running under the KVM 825 hypervisor. It includes a paravirtualized clock, so that instead 826 of relying on a PIT (or probably other) emulation by the 827 underlying device model, the host provides the guest with 828 timing infrastructure such as time of day, and system time 829 830config ARCH_CPUIDLE_HALTPOLL 831 def_bool n 832 prompt "Disable host haltpoll when loading haltpoll driver" 833 help 834 If virtualized under KVM, disable host haltpoll. 835 836config PVH 837 bool "Support for running PVH guests" 838 help 839 This option enables the PVH entry point for guest virtual machines 840 as specified in the x86/HVM direct boot ABI. 841 842config PARAVIRT_TIME_ACCOUNTING 843 bool "Paravirtual steal time accounting" 844 depends on PARAVIRT 845 help 846 Select this option to enable fine granularity task steal time 847 accounting. Time spent executing other tasks in parallel with 848 the current vCPU is discounted from the vCPU power. To account for 849 that, there can be a small performance impact. 850 851 If in doubt, say N here. 852 853config PARAVIRT_CLOCK 854 bool 855 856config JAILHOUSE_GUEST 857 bool "Jailhouse non-root cell support" 858 depends on X86_64 && PCI 859 select X86_PM_TIMER 860 help 861 This option allows to run Linux as guest in a Jailhouse non-root 862 cell. You can leave this option disabled if you only want to start 863 Jailhouse and run Linux afterwards in the root cell. 864 865config ACRN_GUEST 866 bool "ACRN Guest support" 867 depends on X86_64 868 select X86_HV_CALLBACK_VECTOR 869 help 870 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 871 a flexible, lightweight reference open-source hypervisor, built with 872 real-time and safety-criticality in mind. It is built for embedded 873 IOT with small footprint and real-time features. More details can be 874 found in https://projectacrn.org/. 875 876endif #HYPERVISOR_GUEST 877 878source "arch/x86/Kconfig.cpu" 879 880config HPET_TIMER 881 def_bool X86_64 882 prompt "HPET Timer Support" if X86_32 883 help 884 Use the IA-PC HPET (High Precision Event Timer) to manage 885 time in preference to the PIT and RTC, if a HPET is 886 present. 887 HPET is the next generation timer replacing legacy 8254s. 888 The HPET provides a stable time base on SMP 889 systems, unlike the TSC, but it is more expensive to access, 890 as it is off-chip. The interface used is documented 891 in the HPET spec, revision 1. 892 893 You can safely choose Y here. However, HPET will only be 894 activated if the platform and the BIOS support this feature. 895 Otherwise the 8254 will be used for timing services. 896 897 Choose N to continue using the legacy 8254 timer. 898 899config HPET_EMULATE_RTC 900 def_bool y 901 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 902 903# Mark as expert because too many people got it wrong. 904# The code disables itself when not needed. 905config DMI 906 default y 907 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 908 bool "Enable DMI scanning" if EXPERT 909 help 910 Enabled scanning of DMI to identify machine quirks. Say Y 911 here unless you have verified that your setup is not 912 affected by entries in the DMI blacklist. Required by PNP 913 BIOS code. 914 915config GART_IOMMU 916 bool "Old AMD GART IOMMU support" 917 select DMA_OPS 918 select IOMMU_HELPER 919 select SWIOTLB 920 depends on X86_64 && PCI && AMD_NB 921 help 922 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 923 GART based hardware IOMMUs. 924 925 The GART supports full DMA access for devices with 32-bit access 926 limitations, on systems with more than 3 GB. This is usually needed 927 for USB, sound, many IDE/SATA chipsets and some other devices. 928 929 Newer systems typically have a modern AMD IOMMU, supported via 930 the CONFIG_AMD_IOMMU=y config option. 931 932 In normal configurations this driver is only active when needed: 933 there's more than 3 GB of memory and the system contains a 934 32-bit limited device. 935 936 If unsure, say Y. 937 938config MAXSMP 939 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 940 depends on X86_64 && SMP && DEBUG_KERNEL 941 select CPUMASK_OFFSTACK 942 help 943 Enable maximum number of CPUS and NUMA Nodes for this architecture. 944 If unsure, say N. 945 946# 947# The maximum number of CPUs supported: 948# 949# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 950# and which can be configured interactively in the 951# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 952# 953# The ranges are different on 32-bit and 64-bit kernels, depending on 954# hardware capabilities and scalability features of the kernel. 955# 956# ( If MAXSMP is enabled we just use the highest possible value and disable 957# interactive configuration. ) 958# 959 960config NR_CPUS_RANGE_BEGIN 961 int 962 default NR_CPUS_RANGE_END if MAXSMP 963 default 1 if !SMP 964 default 2 965 966config NR_CPUS_RANGE_END 967 int 968 depends on X86_32 969 default 64 if SMP && X86_BIGSMP 970 default 8 if SMP && !X86_BIGSMP 971 default 1 if !SMP 972 973config NR_CPUS_RANGE_END 974 int 975 depends on X86_64 976 default 8192 if SMP && CPUMASK_OFFSTACK 977 default 512 if SMP && !CPUMASK_OFFSTACK 978 default 1 if !SMP 979 980config NR_CPUS_DEFAULT 981 int 982 depends on X86_32 983 default 32 if X86_BIGSMP 984 default 8 if SMP 985 default 1 if !SMP 986 987config NR_CPUS_DEFAULT 988 int 989 depends on X86_64 990 default 8192 if MAXSMP 991 default 64 if SMP 992 default 1 if !SMP 993 994config NR_CPUS 995 int "Maximum number of CPUs" if SMP && !MAXSMP 996 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 997 default NR_CPUS_DEFAULT 998 help 999 This allows you to specify the maximum number of CPUs which this 1000 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1001 supported value is 8192, otherwise the maximum value is 512. The 1002 minimum value which makes sense is 2. 1003 1004 This is purely to save memory: each supported CPU adds about 8KB 1005 to the kernel image. 1006 1007config SCHED_CLUSTER 1008 bool "Cluster scheduler support" 1009 depends on SMP 1010 default y 1011 help 1012 Cluster scheduler support improves the CPU scheduler's decision 1013 making when dealing with machines that have clusters of CPUs. 1014 Cluster usually means a couple of CPUs which are placed closely 1015 by sharing mid-level caches, last-level cache tags or internal 1016 busses. 1017 1018config SCHED_SMT 1019 def_bool y if SMP 1020 1021config SCHED_MC 1022 def_bool y 1023 prompt "Multi-core scheduler support" 1024 depends on SMP 1025 help 1026 Multi-core scheduler support improves the CPU scheduler's decision 1027 making when dealing with multi-core CPU chips at a cost of slightly 1028 increased overhead in some places. If unsure say N here. 1029 1030config SCHED_MC_PRIO 1031 bool "CPU core priorities scheduler support" 1032 depends on SCHED_MC && CPU_SUP_INTEL 1033 select X86_INTEL_PSTATE 1034 select CPU_FREQ 1035 default y 1036 help 1037 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1038 core ordering determined at manufacturing time, which allows 1039 certain cores to reach higher turbo frequencies (when running 1040 single threaded workloads) than others. 1041 1042 Enabling this kernel feature teaches the scheduler about 1043 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1044 scheduler's CPU selection logic accordingly, so that higher 1045 overall system performance can be achieved. 1046 1047 This feature will have no effect on CPUs without this feature. 1048 1049 If unsure say Y here. 1050 1051config UP_LATE_INIT 1052 def_bool y 1053 depends on !SMP && X86_LOCAL_APIC 1054 1055config X86_UP_APIC 1056 bool "Local APIC support on uniprocessors" if !PCI_MSI 1057 default PCI_MSI 1058 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1059 help 1060 A local APIC (Advanced Programmable Interrupt Controller) is an 1061 integrated interrupt controller in the CPU. If you have a single-CPU 1062 system which has a processor with a local APIC, you can say Y here to 1063 enable and use it. If you say Y here even though your machine doesn't 1064 have a local APIC, then the kernel will still run with no slowdown at 1065 all. The local APIC supports CPU-generated self-interrupts (timer, 1066 performance counters), and the NMI watchdog which detects hard 1067 lockups. 1068 1069config X86_UP_IOAPIC 1070 bool "IO-APIC support on uniprocessors" 1071 depends on X86_UP_APIC 1072 help 1073 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1074 SMP-capable replacement for PC-style interrupt controllers. Most 1075 SMP systems and many recent uniprocessor systems have one. 1076 1077 If you have a single-CPU system with an IO-APIC, you can say Y here 1078 to use it. If you say Y here even though your machine doesn't have 1079 an IO-APIC, then the kernel will still run with no slowdown at all. 1080 1081config X86_LOCAL_APIC 1082 def_bool y 1083 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1084 select IRQ_DOMAIN_HIERARCHY 1085 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1086 1087config X86_IO_APIC 1088 def_bool y 1089 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1090 1091config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1092 bool "Reroute for broken boot IRQs" 1093 depends on X86_IO_APIC 1094 help 1095 This option enables a workaround that fixes a source of 1096 spurious interrupts. This is recommended when threaded 1097 interrupt handling is used on systems where the generation of 1098 superfluous "boot interrupts" cannot be disabled. 1099 1100 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1101 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1102 kernel does during interrupt handling). On chipsets where this 1103 boot IRQ generation cannot be disabled, this workaround keeps 1104 the original IRQ line masked so that only the equivalent "boot 1105 IRQ" is delivered to the CPUs. The workaround also tells the 1106 kernel to set up the IRQ handler on the boot IRQ line. In this 1107 way only one interrupt is delivered to the kernel. Otherwise 1108 the spurious second interrupt may cause the kernel to bring 1109 down (vital) interrupt lines. 1110 1111 Only affects "broken" chipsets. Interrupt sharing may be 1112 increased on these systems. 1113 1114config X86_MCE 1115 bool "Machine Check / overheating reporting" 1116 select GENERIC_ALLOCATOR 1117 default y 1118 help 1119 Machine Check support allows the processor to notify the 1120 kernel if it detects a problem (e.g. overheating, data corruption). 1121 The action the kernel takes depends on the severity of the problem, 1122 ranging from warning messages to halting the machine. 1123 1124config X86_MCELOG_LEGACY 1125 bool "Support for deprecated /dev/mcelog character device" 1126 depends on X86_MCE 1127 help 1128 Enable support for /dev/mcelog which is needed by the old mcelog 1129 userspace logging daemon. Consider switching to the new generation 1130 rasdaemon solution. 1131 1132config X86_MCE_INTEL 1133 def_bool y 1134 prompt "Intel MCE features" 1135 depends on X86_MCE && X86_LOCAL_APIC 1136 help 1137 Additional support for intel specific MCE features such as 1138 the thermal monitor. 1139 1140config X86_MCE_AMD 1141 def_bool y 1142 prompt "AMD MCE features" 1143 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1144 help 1145 Additional support for AMD specific MCE features such as 1146 the DRAM Error Threshold. 1147 1148config X86_ANCIENT_MCE 1149 bool "Support for old Pentium 5 / WinChip machine checks" 1150 depends on X86_32 && X86_MCE 1151 help 1152 Include support for machine check handling on old Pentium 5 or WinChip 1153 systems. These typically need to be enabled explicitly on the command 1154 line. 1155 1156config X86_MCE_THRESHOLD 1157 depends on X86_MCE_AMD || X86_MCE_INTEL 1158 def_bool y 1159 1160config X86_MCE_INJECT 1161 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1162 tristate "Machine check injector support" 1163 help 1164 Provide support for injecting machine checks for testing purposes. 1165 If you don't know what a machine check is and you don't do kernel 1166 QA it is safe to say n. 1167 1168source "arch/x86/events/Kconfig" 1169 1170config X86_LEGACY_VM86 1171 bool "Legacy VM86 support" 1172 depends on X86_32 1173 help 1174 This option allows user programs to put the CPU into V8086 1175 mode, which is an 80286-era approximation of 16-bit real mode. 1176 1177 Some very old versions of X and/or vbetool require this option 1178 for user mode setting. Similarly, DOSEMU will use it if 1179 available to accelerate real mode DOS programs. However, any 1180 recent version of DOSEMU, X, or vbetool should be fully 1181 functional even without kernel VM86 support, as they will all 1182 fall back to software emulation. Nevertheless, if you are using 1183 a 16-bit DOS program where 16-bit performance matters, vm86 1184 mode might be faster than emulation and you might want to 1185 enable this option. 1186 1187 Note that any app that works on a 64-bit kernel is unlikely to 1188 need this option, as 64-bit kernels don't, and can't, support 1189 V8086 mode. This option is also unrelated to 16-bit protected 1190 mode and is not needed to run most 16-bit programs under Wine. 1191 1192 Enabling this option increases the complexity of the kernel 1193 and slows down exception handling a tiny bit. 1194 1195 If unsure, say N here. 1196 1197config VM86 1198 bool 1199 default X86_LEGACY_VM86 1200 1201config X86_16BIT 1202 bool "Enable support for 16-bit segments" if EXPERT 1203 default y 1204 depends on MODIFY_LDT_SYSCALL 1205 help 1206 This option is required by programs like Wine to run 16-bit 1207 protected mode legacy code on x86 processors. Disabling 1208 this option saves about 300 bytes on i386, or around 6K text 1209 plus 16K runtime memory on x86-64, 1210 1211config X86_ESPFIX32 1212 def_bool y 1213 depends on X86_16BIT && X86_32 1214 1215config X86_ESPFIX64 1216 def_bool y 1217 depends on X86_16BIT && X86_64 1218 1219config X86_VSYSCALL_EMULATION 1220 bool "Enable vsyscall emulation" if EXPERT 1221 default y 1222 depends on X86_64 1223 help 1224 This enables emulation of the legacy vsyscall page. Disabling 1225 it is roughly equivalent to booting with vsyscall=none, except 1226 that it will also disable the helpful warning if a program 1227 tries to use a vsyscall. With this option set to N, offending 1228 programs will just segfault, citing addresses of the form 1229 0xffffffffff600?00. 1230 1231 This option is required by many programs built before 2013, and 1232 care should be used even with newer programs if set to N. 1233 1234 Disabling this option saves about 7K of kernel size and 1235 possibly 4K of additional runtime pagetable memory. 1236 1237config X86_IOPL_IOPERM 1238 bool "IOPERM and IOPL Emulation" 1239 default y 1240 help 1241 This enables the ioperm() and iopl() syscalls which are necessary 1242 for legacy applications. 1243 1244 Legacy IOPL support is an overbroad mechanism which allows user 1245 space aside of accessing all 65536 I/O ports also to disable 1246 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1247 capabilities and permission from potentially active security 1248 modules. 1249 1250 The emulation restricts the functionality of the syscall to 1251 only allowing the full range I/O port access, but prevents the 1252 ability to disable interrupts from user space which would be 1253 granted if the hardware IOPL mechanism would be used. 1254 1255config TOSHIBA 1256 tristate "Toshiba Laptop support" 1257 depends on X86_32 1258 help 1259 This adds a driver to safely access the System Management Mode of 1260 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1261 not work on models with a Phoenix BIOS. The System Management Mode 1262 is used to set the BIOS and power saving options on Toshiba portables. 1263 1264 For information on utilities to make use of this driver see the 1265 Toshiba Linux utilities web site at: 1266 <http://www.buzzard.org.uk/toshiba/>. 1267 1268 Say Y if you intend to run this kernel on a Toshiba portable. 1269 Say N otherwise. 1270 1271config I8K 1272 tristate "Dell i8k legacy laptop support" 1273 depends on HWMON 1274 depends on PROC_FS 1275 select SENSORS_DELL_SMM 1276 help 1277 This option enables legacy /proc/i8k userspace interface in hwmon 1278 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1279 temperature and allows controlling fan speeds of Dell laptops via 1280 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1281 it reports also power and hotkey status. For fan speed control is 1282 needed userspace package i8kutils. 1283 1284 Say Y if you intend to run this kernel on old Dell laptops or want to 1285 use userspace package i8kutils. 1286 Say N otherwise. 1287 1288config X86_REBOOTFIXUPS 1289 bool "Enable X86 board specific fixups for reboot" 1290 depends on X86_32 1291 help 1292 This enables chipset and/or board specific fixups to be done 1293 in order to get reboot to work correctly. This is only needed on 1294 some combinations of hardware and BIOS. The symptom, for which 1295 this config is intended, is when reboot ends with a stalled/hung 1296 system. 1297 1298 Currently, the only fixup is for the Geode machines using 1299 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1300 1301 Say Y if you want to enable the fixup. Currently, it's safe to 1302 enable this option even if you don't need it. 1303 Say N otherwise. 1304 1305config MICROCODE 1306 bool "CPU microcode loading support" 1307 default y 1308 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1309 help 1310 If you say Y here, you will be able to update the microcode on 1311 Intel and AMD processors. The Intel support is for the IA32 family, 1312 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1313 AMD support is for families 0x10 and later. You will obviously need 1314 the actual microcode binary data itself which is not shipped with 1315 the Linux kernel. 1316 1317 The preferred method to load microcode from a detached initrd is described 1318 in Documentation/x86/microcode.rst. For that you need to enable 1319 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1320 initrd for microcode blobs. 1321 1322 In addition, you can build the microcode into the kernel. For that you 1323 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1324 config option. 1325 1326config MICROCODE_INTEL 1327 bool "Intel microcode loading support" 1328 depends on MICROCODE 1329 default MICROCODE 1330 help 1331 This options enables microcode patch loading support for Intel 1332 processors. 1333 1334 For the current Intel microcode data package go to 1335 <https://downloadcenter.intel.com> and search for 1336 'Linux Processor Microcode Data File'. 1337 1338config MICROCODE_AMD 1339 bool "AMD microcode loading support" 1340 depends on MICROCODE 1341 help 1342 If you select this option, microcode patch loading support for AMD 1343 processors will be enabled. 1344 1345config MICROCODE_OLD_INTERFACE 1346 bool "Ancient loading interface (DEPRECATED)" 1347 default n 1348 depends on MICROCODE 1349 help 1350 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1351 which was used by userspace tools like iucode_tool and microcode.ctl. 1352 It is inadequate because it runs too late to be able to properly 1353 load microcode on a machine and it needs special tools. Instead, you 1354 should've switched to the early loading method with the initrd or 1355 builtin microcode by now: Documentation/x86/microcode.rst 1356 1357config X86_MSR 1358 tristate "/dev/cpu/*/msr - Model-specific register support" 1359 help 1360 This device gives privileged processes access to the x86 1361 Model-Specific Registers (MSRs). It is a character device with 1362 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1363 MSR accesses are directed to a specific CPU on multi-processor 1364 systems. 1365 1366config X86_CPUID 1367 tristate "/dev/cpu/*/cpuid - CPU information support" 1368 help 1369 This device gives processes access to the x86 CPUID instruction to 1370 be executed on a specific processor. It is a character device 1371 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1372 /dev/cpu/31/cpuid. 1373 1374choice 1375 prompt "High Memory Support" 1376 default HIGHMEM4G 1377 depends on X86_32 1378 1379config NOHIGHMEM 1380 bool "off" 1381 help 1382 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1383 However, the address space of 32-bit x86 processors is only 4 1384 Gigabytes large. That means that, if you have a large amount of 1385 physical memory, not all of it can be "permanently mapped" by the 1386 kernel. The physical memory that's not permanently mapped is called 1387 "high memory". 1388 1389 If you are compiling a kernel which will never run on a machine with 1390 more than 1 Gigabyte total physical RAM, answer "off" here (default 1391 choice and suitable for most users). This will result in a "3GB/1GB" 1392 split: 3GB are mapped so that each process sees a 3GB virtual memory 1393 space and the remaining part of the 4GB virtual memory space is used 1394 by the kernel to permanently map as much physical memory as 1395 possible. 1396 1397 If the machine has between 1 and 4 Gigabytes physical RAM, then 1398 answer "4GB" here. 1399 1400 If more than 4 Gigabytes is used then answer "64GB" here. This 1401 selection turns Intel PAE (Physical Address Extension) mode on. 1402 PAE implements 3-level paging on IA32 processors. PAE is fully 1403 supported by Linux, PAE mode is implemented on all recent Intel 1404 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1405 then the kernel will not boot on CPUs that don't support PAE! 1406 1407 The actual amount of total physical memory will either be 1408 auto detected or can be forced by using a kernel command line option 1409 such as "mem=256M". (Try "man bootparam" or see the documentation of 1410 your boot loader (lilo or loadlin) about how to pass options to the 1411 kernel at boot time.) 1412 1413 If unsure, say "off". 1414 1415config HIGHMEM4G 1416 bool "4GB" 1417 help 1418 Select this if you have a 32-bit processor and between 1 and 4 1419 gigabytes of physical RAM. 1420 1421config HIGHMEM64G 1422 bool "64GB" 1423 depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6 1424 select X86_PAE 1425 help 1426 Select this if you have a 32-bit processor and more than 4 1427 gigabytes of physical RAM. 1428 1429endchoice 1430 1431choice 1432 prompt "Memory split" if EXPERT 1433 default VMSPLIT_3G 1434 depends on X86_32 1435 help 1436 Select the desired split between kernel and user memory. 1437 1438 If the address range available to the kernel is less than the 1439 physical memory installed, the remaining memory will be available 1440 as "high memory". Accessing high memory is a little more costly 1441 than low memory, as it needs to be mapped into the kernel first. 1442 Note that increasing the kernel address space limits the range 1443 available to user programs, making the address space there 1444 tighter. Selecting anything other than the default 3G/1G split 1445 will also likely make your kernel incompatible with binary-only 1446 kernel modules. 1447 1448 If you are not absolutely sure what you are doing, leave this 1449 option alone! 1450 1451 config VMSPLIT_3G 1452 bool "3G/1G user/kernel split" 1453 config VMSPLIT_3G_OPT 1454 depends on !X86_PAE 1455 bool "3G/1G user/kernel split (for full 1G low memory)" 1456 config VMSPLIT_2G 1457 bool "2G/2G user/kernel split" 1458 config VMSPLIT_2G_OPT 1459 depends on !X86_PAE 1460 bool "2G/2G user/kernel split (for full 2G low memory)" 1461 config VMSPLIT_1G 1462 bool "1G/3G user/kernel split" 1463endchoice 1464 1465config PAGE_OFFSET 1466 hex 1467 default 0xB0000000 if VMSPLIT_3G_OPT 1468 default 0x80000000 if VMSPLIT_2G 1469 default 0x78000000 if VMSPLIT_2G_OPT 1470 default 0x40000000 if VMSPLIT_1G 1471 default 0xC0000000 1472 depends on X86_32 1473 1474config HIGHMEM 1475 def_bool y 1476 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1477 1478config X86_PAE 1479 bool "PAE (Physical Address Extension) Support" 1480 depends on X86_32 && !HIGHMEM4G 1481 select PHYS_ADDR_T_64BIT 1482 select SWIOTLB 1483 help 1484 PAE is required for NX support, and furthermore enables 1485 larger swapspace support for non-overcommit purposes. It 1486 has the cost of more pagetable lookup overhead, and also 1487 consumes more pagetable space per process. 1488 1489config X86_5LEVEL 1490 bool "Enable 5-level page tables support" 1491 default y 1492 select DYNAMIC_MEMORY_LAYOUT 1493 select SPARSEMEM_VMEMMAP 1494 depends on X86_64 1495 help 1496 5-level paging enables access to larger address space: 1497 upto 128 PiB of virtual address space and 4 PiB of 1498 physical address space. 1499 1500 It will be supported by future Intel CPUs. 1501 1502 A kernel with the option enabled can be booted on machines that 1503 support 4- or 5-level paging. 1504 1505 See Documentation/x86/x86_64/5level-paging.rst for more 1506 information. 1507 1508 Say N if unsure. 1509 1510config X86_DIRECT_GBPAGES 1511 def_bool y 1512 depends on X86_64 1513 help 1514 Certain kernel features effectively disable kernel 1515 linear 1 GB mappings (even if the CPU otherwise 1516 supports them), so don't confuse the user by printing 1517 that we have them enabled. 1518 1519config X86_CPA_STATISTICS 1520 bool "Enable statistic for Change Page Attribute" 1521 depends on DEBUG_FS 1522 help 1523 Expose statistics about the Change Page Attribute mechanism, which 1524 helps to determine the effectiveness of preserving large and huge 1525 page mappings when mapping protections are changed. 1526 1527config X86_MEM_ENCRYPT 1528 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1529 select DYNAMIC_PHYSICAL_MASK 1530 select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS 1531 def_bool n 1532 1533config AMD_MEM_ENCRYPT 1534 bool "AMD Secure Memory Encryption (SME) support" 1535 depends on X86_64 && CPU_SUP_AMD 1536 select DMA_COHERENT_POOL 1537 select ARCH_USE_MEMREMAP_PROT 1538 select INSTRUCTION_DECODER 1539 select ARCH_HAS_CC_PLATFORM 1540 select X86_MEM_ENCRYPT 1541 help 1542 Say yes to enable support for the encryption of system memory. 1543 This requires an AMD processor that supports Secure Memory 1544 Encryption (SME). 1545 1546config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1547 bool "Activate AMD Secure Memory Encryption (SME) by default" 1548 depends on AMD_MEM_ENCRYPT 1549 help 1550 Say yes to have system memory encrypted by default if running on 1551 an AMD processor that supports Secure Memory Encryption (SME). 1552 1553 If set to Y, then the encryption of system memory can be 1554 deactivated with the mem_encrypt=off command line option. 1555 1556 If set to N, then the encryption of system memory can be 1557 activated with the mem_encrypt=on command line option. 1558 1559# Common NUMA Features 1560config NUMA 1561 bool "NUMA Memory Allocation and Scheduler Support" 1562 depends on SMP 1563 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1564 default y if X86_BIGSMP 1565 help 1566 Enable NUMA (Non-Uniform Memory Access) support. 1567 1568 The kernel will try to allocate memory used by a CPU on the 1569 local memory controller of the CPU and add some more 1570 NUMA awareness to the kernel. 1571 1572 For 64-bit this is recommended if the system is Intel Core i7 1573 (or later), AMD Opteron, or EM64T NUMA. 1574 1575 For 32-bit this is only needed if you boot a 32-bit 1576 kernel on a 64-bit NUMA platform. 1577 1578 Otherwise, you should say N. 1579 1580config AMD_NUMA 1581 def_bool y 1582 prompt "Old style AMD Opteron NUMA detection" 1583 depends on X86_64 && NUMA && PCI 1584 help 1585 Enable AMD NUMA node topology detection. You should say Y here if 1586 you have a multi processor AMD system. This uses an old method to 1587 read the NUMA configuration directly from the builtin Northbridge 1588 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1589 which also takes priority if both are compiled in. 1590 1591config X86_64_ACPI_NUMA 1592 def_bool y 1593 prompt "ACPI NUMA detection" 1594 depends on X86_64 && NUMA && ACPI && PCI 1595 select ACPI_NUMA 1596 help 1597 Enable ACPI SRAT based node topology detection. 1598 1599config NUMA_EMU 1600 bool "NUMA emulation" 1601 depends on NUMA 1602 help 1603 Enable NUMA emulation. A flat machine will be split 1604 into virtual nodes when booted with "numa=fake=N", where N is the 1605 number of nodes. This is only useful for debugging. 1606 1607config NODES_SHIFT 1608 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1609 range 1 10 1610 default "10" if MAXSMP 1611 default "6" if X86_64 1612 default "3" 1613 depends on NUMA 1614 help 1615 Specify the maximum number of NUMA Nodes available on the target 1616 system. Increases memory reserved to accommodate various tables. 1617 1618config ARCH_FLATMEM_ENABLE 1619 def_bool y 1620 depends on X86_32 && !NUMA 1621 1622config ARCH_SPARSEMEM_ENABLE 1623 def_bool y 1624 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1625 select SPARSEMEM_STATIC if X86_32 1626 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1627 1628config ARCH_SPARSEMEM_DEFAULT 1629 def_bool X86_64 || (NUMA && X86_32) 1630 1631config ARCH_SELECT_MEMORY_MODEL 1632 def_bool y 1633 depends on ARCH_SPARSEMEM_ENABLE 1634 1635config ARCH_MEMORY_PROBE 1636 bool "Enable sysfs memory/probe interface" 1637 depends on MEMORY_HOTPLUG 1638 help 1639 This option enables a sysfs memory/probe interface for testing. 1640 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1641 If you are unsure how to answer this question, answer N. 1642 1643config ARCH_PROC_KCORE_TEXT 1644 def_bool y 1645 depends on X86_64 && PROC_KCORE 1646 1647config ILLEGAL_POINTER_VALUE 1648 hex 1649 default 0 if X86_32 1650 default 0xdead000000000000 if X86_64 1651 1652config X86_PMEM_LEGACY_DEVICE 1653 bool 1654 1655config X86_PMEM_LEGACY 1656 tristate "Support non-standard NVDIMMs and ADR protected memory" 1657 depends on PHYS_ADDR_T_64BIT 1658 depends on BLK_DEV 1659 select X86_PMEM_LEGACY_DEVICE 1660 select NUMA_KEEP_MEMINFO if NUMA 1661 select LIBNVDIMM 1662 help 1663 Treat memory marked using the non-standard e820 type of 12 as used 1664 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1665 The kernel will offer these regions to the 'pmem' driver so 1666 they can be used for persistent storage. 1667 1668 Say Y if unsure. 1669 1670config HIGHPTE 1671 bool "Allocate 3rd-level pagetables from highmem" 1672 depends on HIGHMEM 1673 help 1674 The VM uses one page table entry for each page of physical memory. 1675 For systems with a lot of RAM, this can be wasteful of precious 1676 low memory. Setting this option will put user-space page table 1677 entries in high memory. 1678 1679config X86_CHECK_BIOS_CORRUPTION 1680 bool "Check for low memory corruption" 1681 help 1682 Periodically check for memory corruption in low memory, which 1683 is suspected to be caused by BIOS. Even when enabled in the 1684 configuration, it is disabled at runtime. Enable it by 1685 setting "memory_corruption_check=1" on the kernel command 1686 line. By default it scans the low 64k of memory every 60 1687 seconds; see the memory_corruption_check_size and 1688 memory_corruption_check_period parameters in 1689 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1690 1691 When enabled with the default parameters, this option has 1692 almost no overhead, as it reserves a relatively small amount 1693 of memory and scans it infrequently. It both detects corruption 1694 and prevents it from affecting the running system. 1695 1696 It is, however, intended as a diagnostic tool; if repeatable 1697 BIOS-originated corruption always affects the same memory, 1698 you can use memmap= to prevent the kernel from using that 1699 memory. 1700 1701config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1702 bool "Set the default setting of memory_corruption_check" 1703 depends on X86_CHECK_BIOS_CORRUPTION 1704 default y 1705 help 1706 Set whether the default state of memory_corruption_check is 1707 on or off. 1708 1709config MATH_EMULATION 1710 bool 1711 depends on MODIFY_LDT_SYSCALL 1712 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1713 help 1714 Linux can emulate a math coprocessor (used for floating point 1715 operations) if you don't have one. 486DX and Pentium processors have 1716 a math coprocessor built in, 486SX and 386 do not, unless you added 1717 a 487DX or 387, respectively. (The messages during boot time can 1718 give you some hints here ["man dmesg"].) Everyone needs either a 1719 coprocessor or this emulation. 1720 1721 If you don't have a math coprocessor, you need to say Y here; if you 1722 say Y here even though you have a coprocessor, the coprocessor will 1723 be used nevertheless. (This behavior can be changed with the kernel 1724 command line option "no387", which comes handy if your coprocessor 1725 is broken. Try "man bootparam" or see the documentation of your boot 1726 loader (lilo or loadlin) about how to pass options to the kernel at 1727 boot time.) This means that it is a good idea to say Y here if you 1728 intend to use this kernel on different machines. 1729 1730 More information about the internals of the Linux math coprocessor 1731 emulation can be found in <file:arch/x86/math-emu/README>. 1732 1733 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1734 kernel, it won't hurt. 1735 1736config MTRR 1737 def_bool y 1738 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1739 help 1740 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1741 the Memory Type Range Registers (MTRRs) may be used to control 1742 processor access to memory ranges. This is most useful if you have 1743 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1744 allows bus write transfers to be combined into a larger transfer 1745 before bursting over the PCI/AGP bus. This can increase performance 1746 of image write operations 2.5 times or more. Saying Y here creates a 1747 /proc/mtrr file which may be used to manipulate your processor's 1748 MTRRs. Typically the X server should use this. 1749 1750 This code has a reasonably generic interface so that similar 1751 control registers on other processors can be easily supported 1752 as well: 1753 1754 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1755 Registers (ARRs) which provide a similar functionality to MTRRs. For 1756 these, the ARRs are used to emulate the MTRRs. 1757 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1758 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1759 write-combining. All of these processors are supported by this code 1760 and it makes sense to say Y here if you have one of them. 1761 1762 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1763 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1764 can lead to all sorts of problems, so it's good to say Y here. 1765 1766 You can safely say Y even if your machine doesn't have MTRRs, you'll 1767 just add about 9 KB to your kernel. 1768 1769 See <file:Documentation/x86/mtrr.rst> for more information. 1770 1771config MTRR_SANITIZER 1772 def_bool y 1773 prompt "MTRR cleanup support" 1774 depends on MTRR 1775 help 1776 Convert MTRR layout from continuous to discrete, so X drivers can 1777 add writeback entries. 1778 1779 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1780 The largest mtrr entry size for a continuous block can be set with 1781 mtrr_chunk_size. 1782 1783 If unsure, say Y. 1784 1785config MTRR_SANITIZER_ENABLE_DEFAULT 1786 int "MTRR cleanup enable value (0-1)" 1787 range 0 1 1788 default "0" 1789 depends on MTRR_SANITIZER 1790 help 1791 Enable mtrr cleanup default value 1792 1793config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1794 int "MTRR cleanup spare reg num (0-7)" 1795 range 0 7 1796 default "1" 1797 depends on MTRR_SANITIZER 1798 help 1799 mtrr cleanup spare entries default, it can be changed via 1800 mtrr_spare_reg_nr=N on the kernel command line. 1801 1802config X86_PAT 1803 def_bool y 1804 prompt "x86 PAT support" if EXPERT 1805 depends on MTRR 1806 help 1807 Use PAT attributes to setup page level cache control. 1808 1809 PATs are the modern equivalents of MTRRs and are much more 1810 flexible than MTRRs. 1811 1812 Say N here if you see bootup problems (boot crash, boot hang, 1813 spontaneous reboots) or a non-working video driver. 1814 1815 If unsure, say Y. 1816 1817config ARCH_USES_PG_UNCACHED 1818 def_bool y 1819 depends on X86_PAT 1820 1821config ARCH_RANDOM 1822 def_bool y 1823 prompt "x86 architectural random number generator" if EXPERT 1824 help 1825 Enable the x86 architectural RDRAND instruction 1826 (Intel Bull Mountain technology) to generate random numbers. 1827 If supported, this is a high bandwidth, cryptographically 1828 secure hardware random number generator. 1829 1830config X86_SMAP 1831 def_bool y 1832 prompt "Supervisor Mode Access Prevention" if EXPERT 1833 help 1834 Supervisor Mode Access Prevention (SMAP) is a security 1835 feature in newer Intel processors. There is a small 1836 performance cost if this enabled and turned on; there is 1837 also a small increase in the kernel size if this is enabled. 1838 1839 If unsure, say Y. 1840 1841config X86_UMIP 1842 def_bool y 1843 prompt "User Mode Instruction Prevention" if EXPERT 1844 help 1845 User Mode Instruction Prevention (UMIP) is a security feature in 1846 some x86 processors. If enabled, a general protection fault is 1847 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1848 executed in user mode. These instructions unnecessarily expose 1849 information about the hardware state. 1850 1851 The vast majority of applications do not use these instructions. 1852 For the very few that do, software emulation is provided in 1853 specific cases in protected and virtual-8086 modes. Emulated 1854 results are dummy. 1855 1856config X86_INTEL_MEMORY_PROTECTION_KEYS 1857 prompt "Memory Protection Keys" 1858 def_bool y 1859 # Note: only available in 64-bit mode 1860 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1861 select ARCH_USES_HIGH_VMA_FLAGS 1862 select ARCH_HAS_PKEYS 1863 help 1864 Memory Protection Keys provides a mechanism for enforcing 1865 page-based protections, but without requiring modification of the 1866 page tables when an application changes protection domains. 1867 1868 For details, see Documentation/core-api/protection-keys.rst 1869 1870 If unsure, say y. 1871 1872choice 1873 prompt "TSX enable mode" 1874 depends on CPU_SUP_INTEL 1875 default X86_INTEL_TSX_MODE_OFF 1876 help 1877 Intel's TSX (Transactional Synchronization Extensions) feature 1878 allows to optimize locking protocols through lock elision which 1879 can lead to a noticeable performance boost. 1880 1881 On the other hand it has been shown that TSX can be exploited 1882 to form side channel attacks (e.g. TAA) and chances are there 1883 will be more of those attacks discovered in the future. 1884 1885 Therefore TSX is not enabled by default (aka tsx=off). An admin 1886 might override this decision by tsx=on the command line parameter. 1887 Even with TSX enabled, the kernel will attempt to enable the best 1888 possible TAA mitigation setting depending on the microcode available 1889 for the particular machine. 1890 1891 This option allows to set the default tsx mode between tsx=on, =off 1892 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1893 details. 1894 1895 Say off if not sure, auto if TSX is in use but it should be used on safe 1896 platforms or on if TSX is in use and the security aspect of tsx is not 1897 relevant. 1898 1899config X86_INTEL_TSX_MODE_OFF 1900 bool "off" 1901 help 1902 TSX is disabled if possible - equals to tsx=off command line parameter. 1903 1904config X86_INTEL_TSX_MODE_ON 1905 bool "on" 1906 help 1907 TSX is always enabled on TSX capable HW - equals the tsx=on command 1908 line parameter. 1909 1910config X86_INTEL_TSX_MODE_AUTO 1911 bool "auto" 1912 help 1913 TSX is enabled on TSX capable HW that is believed to be safe against 1914 side channel attacks- equals the tsx=auto command line parameter. 1915endchoice 1916 1917config X86_SGX 1918 bool "Software Guard eXtensions (SGX)" 1919 depends on X86_64 && CPU_SUP_INTEL 1920 depends on CRYPTO=y 1921 depends on CRYPTO_SHA256=y 1922 select SRCU 1923 select MMU_NOTIFIER 1924 select NUMA_KEEP_MEMINFO if NUMA 1925 select XARRAY_MULTI 1926 help 1927 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1928 that can be used by applications to set aside private regions of code 1929 and data, referred to as enclaves. An enclave's private memory can 1930 only be accessed by code running within the enclave. Accesses from 1931 outside the enclave, including other enclaves, are disallowed by 1932 hardware. 1933 1934 If unsure, say N. 1935 1936config EFI 1937 bool "EFI runtime service support" 1938 depends on ACPI 1939 select UCS2_STRING 1940 select EFI_RUNTIME_WRAPPERS 1941 select ARCH_USE_MEMREMAP_PROT 1942 help 1943 This enables the kernel to use EFI runtime services that are 1944 available (such as the EFI variable services). 1945 1946 This option is only useful on systems that have EFI firmware. 1947 In addition, you should use the latest ELILO loader available 1948 at <http://elilo.sourceforge.net> in order to take advantage 1949 of EFI runtime services. However, even with this option, the 1950 resultant kernel should continue to boot on existing non-EFI 1951 platforms. 1952 1953config EFI_STUB 1954 bool "EFI stub support" 1955 depends on EFI && !X86_USE_3DNOW 1956 depends on $(cc-option,-mabi=ms) || X86_32 1957 select RELOCATABLE 1958 help 1959 This kernel feature allows a bzImage to be loaded directly 1960 by EFI firmware without the use of a bootloader. 1961 1962 See Documentation/admin-guide/efi-stub.rst for more information. 1963 1964config EFI_MIXED 1965 bool "EFI mixed-mode support" 1966 depends on EFI_STUB && X86_64 1967 help 1968 Enabling this feature allows a 64-bit kernel to be booted 1969 on a 32-bit firmware, provided that your CPU supports 64-bit 1970 mode. 1971 1972 Note that it is not possible to boot a mixed-mode enabled 1973 kernel via the EFI boot stub - a bootloader that supports 1974 the EFI handover protocol must be used. 1975 1976 If unsure, say N. 1977 1978source "kernel/Kconfig.hz" 1979 1980config KEXEC 1981 bool "kexec system call" 1982 select KEXEC_CORE 1983 help 1984 kexec is a system call that implements the ability to shutdown your 1985 current kernel, and to start another kernel. It is like a reboot 1986 but it is independent of the system firmware. And like a reboot 1987 you can start any kernel with it, not just Linux. 1988 1989 The name comes from the similarity to the exec system call. 1990 1991 It is an ongoing process to be certain the hardware in a machine 1992 is properly shutdown, so do not be surprised if this code does not 1993 initially work for you. As of this writing the exact hardware 1994 interface is strongly in flux, so no good recommendation can be 1995 made. 1996 1997config KEXEC_FILE 1998 bool "kexec file based system call" 1999 select KEXEC_CORE 2000 select BUILD_BIN2C 2001 depends on X86_64 2002 depends on CRYPTO=y 2003 depends on CRYPTO_SHA256=y 2004 help 2005 This is new version of kexec system call. This system call is 2006 file based and takes file descriptors as system call argument 2007 for kernel and initramfs as opposed to list of segments as 2008 accepted by previous system call. 2009 2010config ARCH_HAS_KEXEC_PURGATORY 2011 def_bool KEXEC_FILE 2012 2013config KEXEC_SIG 2014 bool "Verify kernel signature during kexec_file_load() syscall" 2015 depends on KEXEC_FILE 2016 help 2017 2018 This option makes the kexec_file_load() syscall check for a valid 2019 signature of the kernel image. The image can still be loaded without 2020 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2021 there's a signature that we can check, then it must be valid. 2022 2023 In addition to this option, you need to enable signature 2024 verification for the corresponding kernel image type being 2025 loaded in order for this to work. 2026 2027config KEXEC_SIG_FORCE 2028 bool "Require a valid signature in kexec_file_load() syscall" 2029 depends on KEXEC_SIG 2030 help 2031 This option makes kernel signature verification mandatory for 2032 the kexec_file_load() syscall. 2033 2034config KEXEC_BZIMAGE_VERIFY_SIG 2035 bool "Enable bzImage signature verification support" 2036 depends on KEXEC_SIG 2037 depends on SIGNED_PE_FILE_VERIFICATION 2038 select SYSTEM_TRUSTED_KEYRING 2039 help 2040 Enable bzImage signature verification support. 2041 2042config CRASH_DUMP 2043 bool "kernel crash dumps" 2044 depends on X86_64 || (X86_32 && HIGHMEM) 2045 help 2046 Generate crash dump after being started by kexec. 2047 This should be normally only set in special crash dump kernels 2048 which are loaded in the main kernel with kexec-tools into 2049 a specially reserved region and then later executed after 2050 a crash by kdump/kexec. The crash dump kernel must be compiled 2051 to a memory address not used by the main kernel or BIOS using 2052 PHYSICAL_START, or it must be built as a relocatable image 2053 (CONFIG_RELOCATABLE=y). 2054 For more details see Documentation/admin-guide/kdump/kdump.rst 2055 2056config KEXEC_JUMP 2057 bool "kexec jump" 2058 depends on KEXEC && HIBERNATION 2059 help 2060 Jump between original kernel and kexeced kernel and invoke 2061 code in physical address mode via KEXEC 2062 2063config PHYSICAL_START 2064 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2065 default "0x1000000" 2066 help 2067 This gives the physical address where the kernel is loaded. 2068 2069 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2070 bzImage will decompress itself to above physical address and 2071 run from there. Otherwise, bzImage will run from the address where 2072 it has been loaded by the boot loader and will ignore above physical 2073 address. 2074 2075 In normal kdump cases one does not have to set/change this option 2076 as now bzImage can be compiled as a completely relocatable image 2077 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2078 address. This option is mainly useful for the folks who don't want 2079 to use a bzImage for capturing the crash dump and want to use a 2080 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2081 to be specifically compiled to run from a specific memory area 2082 (normally a reserved region) and this option comes handy. 2083 2084 So if you are using bzImage for capturing the crash dump, 2085 leave the value here unchanged to 0x1000000 and set 2086 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2087 for capturing the crash dump change this value to start of 2088 the reserved region. In other words, it can be set based on 2089 the "X" value as specified in the "crashkernel=YM@XM" 2090 command line boot parameter passed to the panic-ed 2091 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2092 for more details about crash dumps. 2093 2094 Usage of bzImage for capturing the crash dump is recommended as 2095 one does not have to build two kernels. Same kernel can be used 2096 as production kernel and capture kernel. Above option should have 2097 gone away after relocatable bzImage support is introduced. But it 2098 is present because there are users out there who continue to use 2099 vmlinux for dump capture. This option should go away down the 2100 line. 2101 2102 Don't change this unless you know what you are doing. 2103 2104config RELOCATABLE 2105 bool "Build a relocatable kernel" 2106 default y 2107 help 2108 This builds a kernel image that retains relocation information 2109 so it can be loaded someplace besides the default 1MB. 2110 The relocations tend to make the kernel binary about 10% larger, 2111 but are discarded at runtime. 2112 2113 One use is for the kexec on panic case where the recovery kernel 2114 must live at a different physical address than the primary 2115 kernel. 2116 2117 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2118 it has been loaded at and the compile time physical address 2119 (CONFIG_PHYSICAL_START) is used as the minimum location. 2120 2121config RANDOMIZE_BASE 2122 bool "Randomize the address of the kernel image (KASLR)" 2123 depends on RELOCATABLE 2124 default y 2125 help 2126 In support of Kernel Address Space Layout Randomization (KASLR), 2127 this randomizes the physical address at which the kernel image 2128 is decompressed and the virtual address where the kernel 2129 image is mapped, as a security feature that deters exploit 2130 attempts relying on knowledge of the location of kernel 2131 code internals. 2132 2133 On 64-bit, the kernel physical and virtual addresses are 2134 randomized separately. The physical address will be anywhere 2135 between 16MB and the top of physical memory (up to 64TB). The 2136 virtual address will be randomized from 16MB up to 1GB (9 bits 2137 of entropy). Note that this also reduces the memory space 2138 available to kernel modules from 1.5GB to 1GB. 2139 2140 On 32-bit, the kernel physical and virtual addresses are 2141 randomized together. They will be randomized from 16MB up to 2142 512MB (8 bits of entropy). 2143 2144 Entropy is generated using the RDRAND instruction if it is 2145 supported. If RDTSC is supported, its value is mixed into 2146 the entropy pool as well. If neither RDRAND nor RDTSC are 2147 supported, then entropy is read from the i8254 timer. The 2148 usable entropy is limited by the kernel being built using 2149 2GB addressing, and that PHYSICAL_ALIGN must be at a 2150 minimum of 2MB. As a result, only 10 bits of entropy are 2151 theoretically possible, but the implementations are further 2152 limited due to memory layouts. 2153 2154 If unsure, say Y. 2155 2156# Relocation on x86 needs some additional build support 2157config X86_NEED_RELOCS 2158 def_bool y 2159 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2160 2161config PHYSICAL_ALIGN 2162 hex "Alignment value to which kernel should be aligned" 2163 default "0x200000" 2164 range 0x2000 0x1000000 if X86_32 2165 range 0x200000 0x1000000 if X86_64 2166 help 2167 This value puts the alignment restrictions on physical address 2168 where kernel is loaded and run from. Kernel is compiled for an 2169 address which meets above alignment restriction. 2170 2171 If bootloader loads the kernel at a non-aligned address and 2172 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2173 address aligned to above value and run from there. 2174 2175 If bootloader loads the kernel at a non-aligned address and 2176 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2177 load address and decompress itself to the address it has been 2178 compiled for and run from there. The address for which kernel is 2179 compiled already meets above alignment restrictions. Hence the 2180 end result is that kernel runs from a physical address meeting 2181 above alignment restrictions. 2182 2183 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2184 this value must be a multiple of 0x200000. 2185 2186 Don't change this unless you know what you are doing. 2187 2188config DYNAMIC_MEMORY_LAYOUT 2189 bool 2190 help 2191 This option makes base addresses of vmalloc and vmemmap as well as 2192 __PAGE_OFFSET movable during boot. 2193 2194config RANDOMIZE_MEMORY 2195 bool "Randomize the kernel memory sections" 2196 depends on X86_64 2197 depends on RANDOMIZE_BASE 2198 select DYNAMIC_MEMORY_LAYOUT 2199 default RANDOMIZE_BASE 2200 help 2201 Randomizes the base virtual address of kernel memory sections 2202 (physical memory mapping, vmalloc & vmemmap). This security feature 2203 makes exploits relying on predictable memory locations less reliable. 2204 2205 The order of allocations remains unchanged. Entropy is generated in 2206 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2207 configuration have in average 30,000 different possible virtual 2208 addresses for each memory section. 2209 2210 If unsure, say Y. 2211 2212config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2213 hex "Physical memory mapping padding" if EXPERT 2214 depends on RANDOMIZE_MEMORY 2215 default "0xa" if MEMORY_HOTPLUG 2216 default "0x0" 2217 range 0x1 0x40 if MEMORY_HOTPLUG 2218 range 0x0 0x40 2219 help 2220 Define the padding in terabytes added to the existing physical 2221 memory size during kernel memory randomization. It is useful 2222 for memory hotplug support but reduces the entropy available for 2223 address randomization. 2224 2225 If unsure, leave at the default value. 2226 2227config HOTPLUG_CPU 2228 def_bool y 2229 depends on SMP 2230 2231config BOOTPARAM_HOTPLUG_CPU0 2232 bool "Set default setting of cpu0_hotpluggable" 2233 depends on HOTPLUG_CPU 2234 help 2235 Set whether default state of cpu0_hotpluggable is on or off. 2236 2237 Say Y here to enable CPU0 hotplug by default. If this switch 2238 is turned on, there is no need to give cpu0_hotplug kernel 2239 parameter and the CPU0 hotplug feature is enabled by default. 2240 2241 Please note: there are two known CPU0 dependencies if you want 2242 to enable the CPU0 hotplug feature either by this switch or by 2243 cpu0_hotplug kernel parameter. 2244 2245 First, resume from hibernate or suspend always starts from CPU0. 2246 So hibernate and suspend are prevented if CPU0 is offline. 2247 2248 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2249 offline if any interrupt can not migrate out of CPU0. There may 2250 be other CPU0 dependencies. 2251 2252 Please make sure the dependencies are under your control before 2253 you enable this feature. 2254 2255 Say N if you don't want to enable CPU0 hotplug feature by default. 2256 You still can enable the CPU0 hotplug feature at boot by kernel 2257 parameter cpu0_hotplug. 2258 2259config DEBUG_HOTPLUG_CPU0 2260 def_bool n 2261 prompt "Debug CPU0 hotplug" 2262 depends on HOTPLUG_CPU 2263 help 2264 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2265 soon as possible and boots up userspace with CPU0 offlined. User 2266 can online CPU0 back after boot time. 2267 2268 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2269 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2270 compilation or giving cpu0_hotplug kernel parameter at boot. 2271 2272 If unsure, say N. 2273 2274config COMPAT_VDSO 2275 def_bool n 2276 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2277 depends on COMPAT_32 2278 help 2279 Certain buggy versions of glibc will crash if they are 2280 presented with a 32-bit vDSO that is not mapped at the address 2281 indicated in its segment table. 2282 2283 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2284 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2285 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2286 the only released version with the bug, but OpenSUSE 9 2287 contains a buggy "glibc 2.3.2". 2288 2289 The symptom of the bug is that everything crashes on startup, saying: 2290 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2291 2292 Saying Y here changes the default value of the vdso32 boot 2293 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2294 This works around the glibc bug but hurts performance. 2295 2296 If unsure, say N: if you are compiling your own kernel, you 2297 are unlikely to be using a buggy version of glibc. 2298 2299choice 2300 prompt "vsyscall table for legacy applications" 2301 depends on X86_64 2302 default LEGACY_VSYSCALL_XONLY 2303 help 2304 Legacy user code that does not know how to find the vDSO expects 2305 to be able to issue three syscalls by calling fixed addresses in 2306 kernel space. Since this location is not randomized with ASLR, 2307 it can be used to assist security vulnerability exploitation. 2308 2309 This setting can be changed at boot time via the kernel command 2310 line parameter vsyscall=[emulate|xonly|none]. 2311 2312 On a system with recent enough glibc (2.14 or newer) and no 2313 static binaries, you can say None without a performance penalty 2314 to improve security. 2315 2316 If unsure, select "Emulate execution only". 2317 2318 config LEGACY_VSYSCALL_EMULATE 2319 bool "Full emulation" 2320 help 2321 The kernel traps and emulates calls into the fixed vsyscall 2322 address mapping. This makes the mapping non-executable, but 2323 it still contains readable known contents, which could be 2324 used in certain rare security vulnerability exploits. This 2325 configuration is recommended when using legacy userspace 2326 that still uses vsyscalls along with legacy binary 2327 instrumentation tools that require code to be readable. 2328 2329 An example of this type of legacy userspace is running 2330 Pin on an old binary that still uses vsyscalls. 2331 2332 config LEGACY_VSYSCALL_XONLY 2333 bool "Emulate execution only" 2334 help 2335 The kernel traps and emulates calls into the fixed vsyscall 2336 address mapping and does not allow reads. This 2337 configuration is recommended when userspace might use the 2338 legacy vsyscall area but support for legacy binary 2339 instrumentation of legacy code is not needed. It mitigates 2340 certain uses of the vsyscall area as an ASLR-bypassing 2341 buffer. 2342 2343 config LEGACY_VSYSCALL_NONE 2344 bool "None" 2345 help 2346 There will be no vsyscall mapping at all. This will 2347 eliminate any risk of ASLR bypass due to the vsyscall 2348 fixed address mapping. Attempts to use the vsyscalls 2349 will be reported to dmesg, so that either old or 2350 malicious userspace programs can be identified. 2351 2352endchoice 2353 2354config CMDLINE_BOOL 2355 bool "Built-in kernel command line" 2356 help 2357 Allow for specifying boot arguments to the kernel at 2358 build time. On some systems (e.g. embedded ones), it is 2359 necessary or convenient to provide some or all of the 2360 kernel boot arguments with the kernel itself (that is, 2361 to not rely on the boot loader to provide them.) 2362 2363 To compile command line arguments into the kernel, 2364 set this option to 'Y', then fill in the 2365 boot arguments in CONFIG_CMDLINE. 2366 2367 Systems with fully functional boot loaders (i.e. non-embedded) 2368 should leave this option set to 'N'. 2369 2370config CMDLINE 2371 string "Built-in kernel command string" 2372 depends on CMDLINE_BOOL 2373 default "" 2374 help 2375 Enter arguments here that should be compiled into the kernel 2376 image and used at boot time. If the boot loader provides a 2377 command line at boot time, it is appended to this string to 2378 form the full kernel command line, when the system boots. 2379 2380 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2381 change this behavior. 2382 2383 In most cases, the command line (whether built-in or provided 2384 by the boot loader) should specify the device for the root 2385 file system. 2386 2387config CMDLINE_OVERRIDE 2388 bool "Built-in command line overrides boot loader arguments" 2389 depends on CMDLINE_BOOL && CMDLINE != "" 2390 help 2391 Set this option to 'Y' to have the kernel ignore the boot loader 2392 command line, and use ONLY the built-in command line. 2393 2394 This is used to work around broken boot loaders. This should 2395 be set to 'N' under normal conditions. 2396 2397config MODIFY_LDT_SYSCALL 2398 bool "Enable the LDT (local descriptor table)" if EXPERT 2399 default y 2400 help 2401 Linux can allow user programs to install a per-process x86 2402 Local Descriptor Table (LDT) using the modify_ldt(2) system 2403 call. This is required to run 16-bit or segmented code such as 2404 DOSEMU or some Wine programs. It is also used by some very old 2405 threading libraries. 2406 2407 Enabling this feature adds a small amount of overhead to 2408 context switches and increases the low-level kernel attack 2409 surface. Disabling it removes the modify_ldt(2) system call. 2410 2411 Saying 'N' here may make sense for embedded or server kernels. 2412 2413config STRICT_SIGALTSTACK_SIZE 2414 bool "Enforce strict size checking for sigaltstack" 2415 depends on DYNAMIC_SIGFRAME 2416 help 2417 For historical reasons MINSIGSTKSZ is a constant which became 2418 already too small with AVX512 support. Add a mechanism to 2419 enforce strict checking of the sigaltstack size against the 2420 real size of the FPU frame. This option enables the check 2421 by default. It can also be controlled via the kernel command 2422 line option 'strict_sas_size' independent of this config 2423 switch. Enabling it might break existing applications which 2424 allocate a too small sigaltstack but 'work' because they 2425 never get a signal delivered. 2426 2427 Say 'N' unless you want to really enforce this check. 2428 2429source "kernel/livepatch/Kconfig" 2430 2431endmenu 2432 2433config ARCH_HAS_ADD_PAGES 2434 def_bool y 2435 depends on ARCH_ENABLE_MEMORY_HOTPLUG 2436 2437config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 2438 def_bool y 2439 2440config USE_PERCPU_NUMA_NODE_ID 2441 def_bool y 2442 depends on NUMA 2443 2444menu "Power management and ACPI options" 2445 2446config ARCH_HIBERNATION_HEADER 2447 def_bool y 2448 depends on HIBERNATION 2449 2450source "kernel/power/Kconfig" 2451 2452source "drivers/acpi/Kconfig" 2453 2454config X86_APM_BOOT 2455 def_bool y 2456 depends on APM 2457 2458menuconfig APM 2459 tristate "APM (Advanced Power Management) BIOS support" 2460 depends on X86_32 && PM_SLEEP 2461 help 2462 APM is a BIOS specification for saving power using several different 2463 techniques. This is mostly useful for battery powered laptops with 2464 APM compliant BIOSes. If you say Y here, the system time will be 2465 reset after a RESUME operation, the /proc/apm device will provide 2466 battery status information, and user-space programs will receive 2467 notification of APM "events" (e.g. battery status change). 2468 2469 If you select "Y" here, you can disable actual use of the APM 2470 BIOS by passing the "apm=off" option to the kernel at boot time. 2471 2472 Note that the APM support is almost completely disabled for 2473 machines with more than one CPU. 2474 2475 In order to use APM, you will need supporting software. For location 2476 and more information, read <file:Documentation/power/apm-acpi.rst> 2477 and the Battery Powered Linux mini-HOWTO, available from 2478 <http://www.tldp.org/docs.html#howto>. 2479 2480 This driver does not spin down disk drives (see the hdparm(8) 2481 manpage ("man 8 hdparm") for that), and it doesn't turn off 2482 VESA-compliant "green" monitors. 2483 2484 This driver does not support the TI 4000M TravelMate and the ACER 2485 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2486 desktop machines also don't have compliant BIOSes, and this driver 2487 may cause those machines to panic during the boot phase. 2488 2489 Generally, if you don't have a battery in your machine, there isn't 2490 much point in using this driver and you should say N. If you get 2491 random kernel OOPSes or reboots that don't seem to be related to 2492 anything, try disabling/enabling this option (or disabling/enabling 2493 APM in your BIOS). 2494 2495 Some other things you should try when experiencing seemingly random, 2496 "weird" problems: 2497 2498 1) make sure that you have enough swap space and that it is 2499 enabled. 2500 2) pass the "no-hlt" option to the kernel 2501 3) switch on floating point emulation in the kernel and pass 2502 the "no387" option to the kernel 2503 4) pass the "floppy=nodma" option to the kernel 2504 5) pass the "mem=4M" option to the kernel (thereby disabling 2505 all but the first 4 MB of RAM) 2506 6) make sure that the CPU is not over clocked. 2507 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2508 8) disable the cache from your BIOS settings 2509 9) install a fan for the video card or exchange video RAM 2510 10) install a better fan for the CPU 2511 11) exchange RAM chips 2512 12) exchange the motherboard. 2513 2514 To compile this driver as a module, choose M here: the 2515 module will be called apm. 2516 2517if APM 2518 2519config APM_IGNORE_USER_SUSPEND 2520 bool "Ignore USER SUSPEND" 2521 help 2522 This option will ignore USER SUSPEND requests. On machines with a 2523 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2524 series notebooks, it is necessary to say Y because of a BIOS bug. 2525 2526config APM_DO_ENABLE 2527 bool "Enable PM at boot time" 2528 help 2529 Enable APM features at boot time. From page 36 of the APM BIOS 2530 specification: "When disabled, the APM BIOS does not automatically 2531 power manage devices, enter the Standby State, enter the Suspend 2532 State, or take power saving steps in response to CPU Idle calls." 2533 This driver will make CPU Idle calls when Linux is idle (unless this 2534 feature is turned off -- see "Do CPU IDLE calls", below). This 2535 should always save battery power, but more complicated APM features 2536 will be dependent on your BIOS implementation. You may need to turn 2537 this option off if your computer hangs at boot time when using APM 2538 support, or if it beeps continuously instead of suspending. Turn 2539 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2540 T400CDT. This is off by default since most machines do fine without 2541 this feature. 2542 2543config APM_CPU_IDLE 2544 depends on CPU_IDLE 2545 bool "Make CPU Idle calls when idle" 2546 help 2547 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2548 On some machines, this can activate improved power savings, such as 2549 a slowed CPU clock rate, when the machine is idle. These idle calls 2550 are made after the idle loop has run for some length of time (e.g., 2551 333 mS). On some machines, this will cause a hang at boot time or 2552 whenever the CPU becomes idle. (On machines with more than one CPU, 2553 this option does nothing.) 2554 2555config APM_DISPLAY_BLANK 2556 bool "Enable console blanking using APM" 2557 help 2558 Enable console blanking using the APM. Some laptops can use this to 2559 turn off the LCD backlight when the screen blanker of the Linux 2560 virtual console blanks the screen. Note that this is only used by 2561 the virtual console screen blanker, and won't turn off the backlight 2562 when using the X Window system. This also doesn't have anything to 2563 do with your VESA-compliant power-saving monitor. Further, this 2564 option doesn't work for all laptops -- it might not turn off your 2565 backlight at all, or it might print a lot of errors to the console, 2566 especially if you are using gpm. 2567 2568config APM_ALLOW_INTS 2569 bool "Allow interrupts during APM BIOS calls" 2570 help 2571 Normally we disable external interrupts while we are making calls to 2572 the APM BIOS as a measure to lessen the effects of a badly behaving 2573 BIOS implementation. The BIOS should reenable interrupts if it 2574 needs to. Unfortunately, some BIOSes do not -- especially those in 2575 many of the newer IBM Thinkpads. If you experience hangs when you 2576 suspend, try setting this to Y. Otherwise, say N. 2577 2578endif # APM 2579 2580source "drivers/cpufreq/Kconfig" 2581 2582source "drivers/cpuidle/Kconfig" 2583 2584source "drivers/idle/Kconfig" 2585 2586endmenu 2587 2588 2589menu "Bus options (PCI etc.)" 2590 2591choice 2592 prompt "PCI access mode" 2593 depends on X86_32 && PCI 2594 default PCI_GOANY 2595 help 2596 On PCI systems, the BIOS can be used to detect the PCI devices and 2597 determine their configuration. However, some old PCI motherboards 2598 have BIOS bugs and may crash if this is done. Also, some embedded 2599 PCI-based systems don't have any BIOS at all. Linux can also try to 2600 detect the PCI hardware directly without using the BIOS. 2601 2602 With this option, you can specify how Linux should detect the 2603 PCI devices. If you choose "BIOS", the BIOS will be used, 2604 if you choose "Direct", the BIOS won't be used, and if you 2605 choose "MMConfig", then PCI Express MMCONFIG will be used. 2606 If you choose "Any", the kernel will try MMCONFIG, then the 2607 direct access method and falls back to the BIOS if that doesn't 2608 work. If unsure, go with the default, which is "Any". 2609 2610config PCI_GOBIOS 2611 bool "BIOS" 2612 2613config PCI_GOMMCONFIG 2614 bool "MMConfig" 2615 2616config PCI_GODIRECT 2617 bool "Direct" 2618 2619config PCI_GOOLPC 2620 bool "OLPC XO-1" 2621 depends on OLPC 2622 2623config PCI_GOANY 2624 bool "Any" 2625 2626endchoice 2627 2628config PCI_BIOS 2629 def_bool y 2630 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2631 2632# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2633config PCI_DIRECT 2634 def_bool y 2635 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2636 2637config PCI_MMCONFIG 2638 bool "Support mmconfig PCI config space access" if X86_64 2639 default y 2640 depends on PCI && (ACPI || JAILHOUSE_GUEST) 2641 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2642 2643config PCI_OLPC 2644 def_bool y 2645 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2646 2647config PCI_XEN 2648 def_bool y 2649 depends on PCI && XEN 2650 2651config MMCONF_FAM10H 2652 def_bool y 2653 depends on X86_64 && PCI_MMCONFIG && ACPI 2654 2655config PCI_CNB20LE_QUIRK 2656 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2657 depends on PCI 2658 help 2659 Read the PCI windows out of the CNB20LE host bridge. This allows 2660 PCI hotplug to work on systems with the CNB20LE chipset which do 2661 not have ACPI. 2662 2663 There's no public spec for this chipset, and this functionality 2664 is known to be incomplete. 2665 2666 You should say N unless you know you need this. 2667 2668config ISA_BUS 2669 bool "ISA bus support on modern systems" if EXPERT 2670 help 2671 Expose ISA bus device drivers and options available for selection and 2672 configuration. Enable this option if your target machine has an ISA 2673 bus. ISA is an older system, displaced by PCI and newer bus 2674 architectures -- if your target machine is modern, it probably does 2675 not have an ISA bus. 2676 2677 If unsure, say N. 2678 2679# x86_64 have no ISA slots, but can have ISA-style DMA. 2680config ISA_DMA_API 2681 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2682 default y 2683 help 2684 Enables ISA-style DMA support for devices requiring such controllers. 2685 If unsure, say Y. 2686 2687if X86_32 2688 2689config ISA 2690 bool "ISA support" 2691 help 2692 Find out whether you have ISA slots on your motherboard. ISA is the 2693 name of a bus system, i.e. the way the CPU talks to the other stuff 2694 inside your box. Other bus systems are PCI, EISA, MicroChannel 2695 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2696 newer boards don't support it. If you have ISA, say Y, otherwise N. 2697 2698config SCx200 2699 tristate "NatSemi SCx200 support" 2700 help 2701 This provides basic support for National Semiconductor's 2702 (now AMD's) Geode processors. The driver probes for the 2703 PCI-IDs of several on-chip devices, so its a good dependency 2704 for other scx200_* drivers. 2705 2706 If compiled as a module, the driver is named scx200. 2707 2708config SCx200HR_TIMER 2709 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2710 depends on SCx200 2711 default y 2712 help 2713 This driver provides a clocksource built upon the on-chip 2714 27MHz high-resolution timer. Its also a workaround for 2715 NSC Geode SC-1100's buggy TSC, which loses time when the 2716 processor goes idle (as is done by the scheduler). The 2717 other workaround is idle=poll boot option. 2718 2719config OLPC 2720 bool "One Laptop Per Child support" 2721 depends on !X86_PAE 2722 select GPIOLIB 2723 select OF 2724 select OF_PROMTREE 2725 select IRQ_DOMAIN 2726 select OLPC_EC 2727 help 2728 Add support for detecting the unique features of the OLPC 2729 XO hardware. 2730 2731config OLPC_XO1_PM 2732 bool "OLPC XO-1 Power Management" 2733 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2734 help 2735 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2736 2737config OLPC_XO1_RTC 2738 bool "OLPC XO-1 Real Time Clock" 2739 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2740 help 2741 Add support for the XO-1 real time clock, which can be used as a 2742 programmable wakeup source. 2743 2744config OLPC_XO1_SCI 2745 bool "OLPC XO-1 SCI extras" 2746 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2747 depends on INPUT=y 2748 select POWER_SUPPLY 2749 help 2750 Add support for SCI-based features of the OLPC XO-1 laptop: 2751 - EC-driven system wakeups 2752 - Power button 2753 - Ebook switch 2754 - Lid switch 2755 - AC adapter status updates 2756 - Battery status updates 2757 2758config OLPC_XO15_SCI 2759 bool "OLPC XO-1.5 SCI extras" 2760 depends on OLPC && ACPI 2761 select POWER_SUPPLY 2762 help 2763 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2764 - EC-driven system wakeups 2765 - AC adapter status updates 2766 - Battery status updates 2767 2768config ALIX 2769 bool "PCEngines ALIX System Support (LED setup)" 2770 select GPIOLIB 2771 help 2772 This option enables system support for the PCEngines ALIX. 2773 At present this just sets up LEDs for GPIO control on 2774 ALIX2/3/6 boards. However, other system specific setup should 2775 get added here. 2776 2777 Note: You must still enable the drivers for GPIO and LED support 2778 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2779 2780 Note: You have to set alix.force=1 for boards with Award BIOS. 2781 2782config NET5501 2783 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2784 select GPIOLIB 2785 help 2786 This option enables system support for the Soekris Engineering net5501. 2787 2788config GEOS 2789 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2790 select GPIOLIB 2791 depends on DMI 2792 help 2793 This option enables system support for the Traverse Technologies GEOS. 2794 2795config TS5500 2796 bool "Technologic Systems TS-5500 platform support" 2797 depends on MELAN 2798 select CHECK_SIGNATURE 2799 select NEW_LEDS 2800 select LEDS_CLASS 2801 help 2802 This option enables system support for the Technologic Systems TS-5500. 2803 2804endif # X86_32 2805 2806config AMD_NB 2807 def_bool y 2808 depends on CPU_SUP_AMD && PCI 2809 2810endmenu 2811 2812 2813menu "Binary Emulations" 2814 2815config IA32_EMULATION 2816 bool "IA32 Emulation" 2817 depends on X86_64 2818 select ARCH_WANT_OLD_COMPAT_IPC 2819 select BINFMT_ELF 2820 select COMPAT_OLD_SIGACTION 2821 help 2822 Include code to run legacy 32-bit programs under a 2823 64-bit kernel. You should likely turn this on, unless you're 2824 100% sure that you don't have any 32-bit programs left. 2825 2826config IA32_AOUT 2827 tristate "IA32 a.out support" 2828 depends on IA32_EMULATION 2829 depends on BROKEN 2830 help 2831 Support old a.out binaries in the 32bit emulation. 2832 2833config X86_X32 2834 bool "x32 ABI for 64-bit mode" 2835 depends on X86_64 2836 help 2837 Include code to run binaries for the x32 native 32-bit ABI 2838 for 64-bit processors. An x32 process gets access to the 2839 full 64-bit register file and wide data path while leaving 2840 pointers at 32 bits for smaller memory footprint. 2841 2842 You will need a recent binutils (2.22 or later) with 2843 elf32_x86_64 support enabled to compile a kernel with this 2844 option set. 2845 2846config COMPAT_32 2847 def_bool y 2848 depends on IA32_EMULATION || X86_32 2849 select HAVE_UID16 2850 select OLD_SIGSUSPEND3 2851 2852config COMPAT 2853 def_bool y 2854 depends on IA32_EMULATION || X86_X32 2855 2856if COMPAT 2857config COMPAT_FOR_U64_ALIGNMENT 2858 def_bool y 2859 2860config SYSVIPC_COMPAT 2861 def_bool y 2862 depends on SYSVIPC 2863endif 2864 2865endmenu 2866 2867 2868config HAVE_ATOMIC_IOMAP 2869 def_bool y 2870 depends on X86_32 2871 2872source "arch/x86/kvm/Kconfig" 2873 2874source "arch/x86/Kconfig.assembler" 2875