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 HAVE_DEBUG_STACKOVERFLOW 18 select MODULES_USE_ELF_REL 19 select OLD_SIGACTION 20 select GENERIC_VDSO_32 21 22config X86_64 23 def_bool y 24 depends on 64BIT 25 # Options that are inherently 64-bit kernel only: 26 select ARCH_HAS_GIGANTIC_PAGE 27 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 28 select ARCH_USE_CMPXCHG_LOCKREF 29 select HAVE_ARCH_SOFT_DIRTY 30 select MODULES_USE_ELF_RELA 31 select NEED_DMA_MAP_STATE 32 select SWIOTLB 33 34config FORCE_DYNAMIC_FTRACE 35 def_bool y 36 depends on X86_32 37 depends on FUNCTION_TRACER 38 select DYNAMIC_FTRACE 39 help 40 We keep the static function tracing (!DYNAMIC_FTRACE) around 41 in order to test the non static function tracing in the 42 generic code, as other architectures still use it. But we 43 only need to keep it around for x86_64. No need to keep it 44 for x86_32. For x86_32, force DYNAMIC_FTRACE. 45# 46# Arch settings 47# 48# ( Note that options that are marked 'if X86_64' could in principle be 49# ported to 32-bit as well. ) 50# 51config X86 52 def_bool y 53 # 54 # Note: keep this list sorted alphabetically 55 # 56 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 57 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 58 select ARCH_32BIT_OFF_T if X86_32 59 select ARCH_CLOCKSOURCE_INIT 60 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 61 select ARCH_HAS_DEBUG_VIRTUAL 62 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 63 select ARCH_HAS_DEVMEM_IS_ALLOWED 64 select ARCH_HAS_EARLY_DEBUG if KGDB 65 select ARCH_HAS_ELF_RANDOMIZE 66 select ARCH_HAS_FAST_MULTIPLIER 67 select ARCH_HAS_FILTER_PGPROT 68 select ARCH_HAS_FORTIFY_SOURCE 69 select ARCH_HAS_GCOV_PROFILE_ALL 70 select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION 71 select ARCH_HAS_MEM_ENCRYPT 72 select ARCH_HAS_MEMBARRIER_SYNC_CORE 73 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 74 select ARCH_HAS_PMEM_API if X86_64 75 select ARCH_HAS_PTE_DEVMAP if X86_64 76 select ARCH_HAS_PTE_SPECIAL 77 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 78 select ARCH_HAS_COPY_MC if X86_64 79 select ARCH_HAS_SET_MEMORY 80 select ARCH_HAS_SET_DIRECT_MAP 81 select ARCH_HAS_STRICT_KERNEL_RWX 82 select ARCH_HAS_STRICT_MODULE_RWX 83 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 84 select ARCH_HAS_SYSCALL_WRAPPER 85 select ARCH_HAS_UBSAN_SANITIZE_ALL 86 select ARCH_HAS_DEBUG_WX 87 select ARCH_HAVE_NMI_SAFE_CMPXCHG 88 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 89 select ARCH_MIGHT_HAVE_PC_PARPORT 90 select ARCH_MIGHT_HAVE_PC_SERIO 91 select ARCH_STACKWALK 92 select ARCH_SUPPORTS_ACPI 93 select ARCH_SUPPORTS_ATOMIC_RMW 94 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 95 select ARCH_USE_BUILTIN_BSWAP 96 select ARCH_USE_QUEUED_RWLOCKS 97 select ARCH_USE_QUEUED_SPINLOCKS 98 select ARCH_USE_SYM_ANNOTATIONS 99 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 100 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 101 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 102 select ARCH_WANT_HUGE_PMD_SHARE 103 select ARCH_WANT_LD_ORPHAN_WARN 104 select ARCH_WANTS_THP_SWAP if X86_64 105 select BUILDTIME_TABLE_SORT 106 select CLKEVT_I8253 107 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 108 select CLOCKSOURCE_WATCHDOG 109 select DCACHE_WORD_ACCESS 110 select EDAC_ATOMIC_SCRUB 111 select EDAC_SUPPORT 112 select GENERIC_CLOCKEVENTS 113 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 114 select GENERIC_CLOCKEVENTS_MIN_ADJUST 115 select GENERIC_CMOS_UPDATE 116 select GENERIC_CPU_AUTOPROBE 117 select GENERIC_CPU_VULNERABILITIES 118 select GENERIC_EARLY_IOREMAP 119 select GENERIC_ENTRY 120 select GENERIC_FIND_FIRST_BIT 121 select GENERIC_IOMAP 122 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 123 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 124 select GENERIC_IRQ_MIGRATION if SMP 125 select GENERIC_IRQ_PROBE 126 select GENERIC_IRQ_RESERVATION_MODE 127 select GENERIC_IRQ_SHOW 128 select GENERIC_PENDING_IRQ if SMP 129 select GENERIC_PTDUMP 130 select GENERIC_SMP_IDLE_THREAD 131 select GENERIC_STRNCPY_FROM_USER 132 select GENERIC_STRNLEN_USER 133 select GENERIC_TIME_VSYSCALL 134 select GENERIC_GETTIMEOFDAY 135 select GENERIC_VDSO_TIME_NS 136 select GUP_GET_PTE_LOW_HIGH if X86_PAE 137 select HARDIRQS_SW_RESEND 138 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 139 select HAVE_ACPI_APEI if ACPI 140 select HAVE_ACPI_APEI_NMI if ACPI 141 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 142 select HAVE_ARCH_AUDITSYSCALL 143 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 144 select HAVE_ARCH_JUMP_LABEL 145 select HAVE_ARCH_JUMP_LABEL_RELATIVE 146 select HAVE_ARCH_KASAN if X86_64 147 select HAVE_ARCH_KASAN_VMALLOC if X86_64 148 select HAVE_ARCH_KGDB 149 select HAVE_ARCH_MMAP_RND_BITS if MMU 150 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 151 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 152 select HAVE_ARCH_PREL32_RELOCATIONS 153 select HAVE_ARCH_SECCOMP_FILTER 154 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 155 select HAVE_ARCH_STACKLEAK 156 select HAVE_ARCH_TRACEHOOK 157 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 158 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 159 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 160 select HAVE_ARCH_VMAP_STACK if X86_64 161 select HAVE_ARCH_WITHIN_STACK_FRAMES 162 select HAVE_ASM_MODVERSIONS 163 select HAVE_CMPXCHG_DOUBLE 164 select HAVE_CMPXCHG_LOCAL 165 select HAVE_CONTEXT_TRACKING if X86_64 166 select HAVE_C_RECORDMCOUNT 167 select HAVE_DEBUG_KMEMLEAK 168 select HAVE_DMA_CONTIGUOUS 169 select HAVE_DYNAMIC_FTRACE 170 select HAVE_DYNAMIC_FTRACE_WITH_REGS 171 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 172 select HAVE_EBPF_JIT 173 select HAVE_EFFICIENT_UNALIGNED_ACCESS 174 select HAVE_EISA 175 select HAVE_EXIT_THREAD 176 select HAVE_FAST_GUP 177 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 178 select HAVE_FTRACE_MCOUNT_RECORD 179 select HAVE_FUNCTION_GRAPH_TRACER 180 select HAVE_FUNCTION_TRACER 181 select HAVE_GCC_PLUGINS 182 select HAVE_HW_BREAKPOINT 183 select HAVE_IDE 184 select HAVE_IOREMAP_PROT 185 select HAVE_IRQ_TIME_ACCOUNTING 186 select HAVE_KERNEL_BZIP2 187 select HAVE_KERNEL_GZIP 188 select HAVE_KERNEL_LZ4 189 select HAVE_KERNEL_LZMA 190 select HAVE_KERNEL_LZO 191 select HAVE_KERNEL_XZ 192 select HAVE_KERNEL_ZSTD 193 select HAVE_KPROBES 194 select HAVE_KPROBES_ON_FTRACE 195 select HAVE_FUNCTION_ERROR_INJECTION 196 select HAVE_KRETPROBES 197 select HAVE_KVM 198 select HAVE_LIVEPATCH if X86_64 199 select HAVE_MIXED_BREAKPOINTS_REGS 200 select HAVE_MOD_ARCH_SPECIFIC 201 select HAVE_MOVE_PMD 202 select HAVE_NMI 203 select HAVE_OPROFILE 204 select HAVE_OPTPROBES 205 select HAVE_PCSPKR_PLATFORM 206 select HAVE_PERF_EVENTS 207 select HAVE_PERF_EVENTS_NMI 208 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 209 select HAVE_PCI 210 select HAVE_PERF_REGS 211 select HAVE_PERF_USER_STACK_DUMP 212 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 213 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 214 select HAVE_REGS_AND_STACK_ACCESS_API 215 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 216 select HAVE_FUNCTION_ARG_ACCESS_API 217 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 218 select HAVE_STACK_VALIDATION if X86_64 219 select HAVE_STATIC_CALL 220 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION 221 select HAVE_RSEQ 222 select HAVE_SYSCALL_TRACEPOINTS 223 select HAVE_UNSTABLE_SCHED_CLOCK 224 select HAVE_USER_RETURN_NOTIFIER 225 select HAVE_GENERIC_VDSO 226 select HOTPLUG_SMT if SMP 227 select IRQ_FORCED_THREADING 228 select NEED_SG_DMA_LENGTH 229 select PCI_DOMAINS if PCI 230 select PCI_LOCKLESS_CONFIG if PCI 231 select PERF_EVENTS 232 select RTC_LIB 233 select RTC_MC146818_LIB 234 select SPARSE_IRQ 235 select SRCU 236 select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE) 237 select SYSCTL_EXCEPTION_TRACE 238 select THREAD_INFO_IN_TASK 239 select USER_STACKTRACE_SUPPORT 240 select VIRT_TO_BUS 241 select HAVE_ARCH_KCSAN if X86_64 242 select X86_FEATURE_NAMES if PROC_FS 243 select PROC_PID_ARCH_STATUS if PROC_FS 244 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 245 246config INSTRUCTION_DECODER 247 def_bool y 248 depends on KPROBES || PERF_EVENTS || UPROBES 249 250config OUTPUT_FORMAT 251 string 252 default "elf32-i386" if X86_32 253 default "elf64-x86-64" if X86_64 254 255config LOCKDEP_SUPPORT 256 def_bool y 257 258config STACKTRACE_SUPPORT 259 def_bool y 260 261config MMU 262 def_bool y 263 264config ARCH_MMAP_RND_BITS_MIN 265 default 28 if 64BIT 266 default 8 267 268config ARCH_MMAP_RND_BITS_MAX 269 default 32 if 64BIT 270 default 16 271 272config ARCH_MMAP_RND_COMPAT_BITS_MIN 273 default 8 274 275config ARCH_MMAP_RND_COMPAT_BITS_MAX 276 default 16 277 278config SBUS 279 bool 280 281config GENERIC_ISA_DMA 282 def_bool y 283 depends on ISA_DMA_API 284 285config GENERIC_BUG 286 def_bool y 287 depends on BUG 288 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 289 290config GENERIC_BUG_RELATIVE_POINTERS 291 bool 292 293config ARCH_MAY_HAVE_PC_FDC 294 def_bool y 295 depends on ISA_DMA_API 296 297config GENERIC_CALIBRATE_DELAY 298 def_bool y 299 300config ARCH_HAS_CPU_RELAX 301 def_bool y 302 303config ARCH_HAS_CACHE_LINE_SIZE 304 def_bool y 305 306config ARCH_HAS_FILTER_PGPROT 307 def_bool y 308 309config HAVE_SETUP_PER_CPU_AREA 310 def_bool y 311 312config NEED_PER_CPU_EMBED_FIRST_CHUNK 313 def_bool y 314 315config NEED_PER_CPU_PAGE_FIRST_CHUNK 316 def_bool y 317 318config ARCH_HIBERNATION_POSSIBLE 319 def_bool y 320 321config ARCH_SUSPEND_POSSIBLE 322 def_bool y 323 324config ARCH_WANT_GENERAL_HUGETLB 325 def_bool y 326 327config ZONE_DMA32 328 def_bool y if X86_64 329 330config AUDIT_ARCH 331 def_bool y if X86_64 332 333config ARCH_SUPPORTS_DEBUG_PAGEALLOC 334 def_bool y 335 336config KASAN_SHADOW_OFFSET 337 hex 338 depends on KASAN 339 default 0xdffffc0000000000 340 341config HAVE_INTEL_TXT 342 def_bool y 343 depends on INTEL_IOMMU && ACPI 344 345config X86_32_SMP 346 def_bool y 347 depends on X86_32 && SMP 348 349config X86_64_SMP 350 def_bool y 351 depends on X86_64 && SMP 352 353config X86_32_LAZY_GS 354 def_bool y 355 depends on X86_32 && !STACKPROTECTOR 356 357config ARCH_SUPPORTS_UPROBES 358 def_bool y 359 360config FIX_EARLYCON_MEM 361 def_bool y 362 363config DYNAMIC_PHYSICAL_MASK 364 bool 365 366config PGTABLE_LEVELS 367 int 368 default 5 if X86_5LEVEL 369 default 4 if X86_64 370 default 3 if X86_PAE 371 default 2 372 373config CC_HAS_SANE_STACKPROTECTOR 374 bool 375 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 376 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 377 help 378 We have to make sure stack protector is unconditionally disabled if 379 the compiler produces broken code. 380 381menu "Processor type and features" 382 383config ZONE_DMA 384 bool "DMA memory allocation support" if EXPERT 385 default y 386 help 387 DMA memory allocation support allows devices with less than 32-bit 388 addressing to allocate within the first 16MB of address space. 389 Disable if no such devices will be used. 390 391 If unsure, say Y. 392 393config SMP 394 bool "Symmetric multi-processing support" 395 help 396 This enables support for systems with more than one CPU. If you have 397 a system with only one CPU, say N. If you have a system with more 398 than one CPU, say Y. 399 400 If you say N here, the kernel will run on uni- and multiprocessor 401 machines, but will use only one CPU of a multiprocessor machine. If 402 you say Y here, the kernel will run on many, but not all, 403 uniprocessor machines. On a uniprocessor machine, the kernel 404 will run faster if you say N here. 405 406 Note that if you say Y here and choose architecture "586" or 407 "Pentium" under "Processor family", the kernel will not work on 486 408 architectures. Similarly, multiprocessor kernels for the "PPro" 409 architecture may not work on all Pentium based boards. 410 411 People using multiprocessor machines who say Y here should also say 412 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 413 Management" code will be disabled if you say Y here. 414 415 See also <file:Documentation/x86/i386/IO-APIC.rst>, 416 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 417 <http://www.tldp.org/docs.html#howto>. 418 419 If you don't know what to do here, say N. 420 421config X86_FEATURE_NAMES 422 bool "Processor feature human-readable names" if EMBEDDED 423 default y 424 help 425 This option compiles in a table of x86 feature bits and corresponding 426 names. This is required to support /proc/cpuinfo and a few kernel 427 messages. You can disable this to save space, at the expense of 428 making those few kernel messages show numeric feature bits instead. 429 430 If in doubt, say Y. 431 432config X86_X2APIC 433 bool "Support x2apic" 434 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 435 help 436 This enables x2apic support on CPUs that have this feature. 437 438 This allows 32-bit apic IDs (so it can support very large systems), 439 and accesses the local apic via MSRs not via mmio. 440 441 If you don't know what to do here, say N. 442 443config X86_MPPARSE 444 bool "Enable MPS table" if ACPI || SFI 445 default y 446 depends on X86_LOCAL_APIC 447 help 448 For old smp systems that do not have proper acpi support. Newer systems 449 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 450 451config GOLDFISH 452 def_bool y 453 depends on X86_GOLDFISH 454 455config RETPOLINE 456 bool "Avoid speculative indirect branches in kernel" 457 default y 458 help 459 Compile kernel with the retpoline compiler options to guard against 460 kernel-to-user data leaks by avoiding speculative indirect 461 branches. Requires a compiler with -mindirect-branch=thunk-extern 462 support for full protection. The kernel may run slower. 463 464config X86_CPU_RESCTRL 465 bool "x86 CPU resource control support" 466 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 467 select KERNFS 468 select PROC_CPU_RESCTRL if PROC_FS 469 help 470 Enable x86 CPU resource control support. 471 472 Provide support for the allocation and monitoring of system resources 473 usage by the CPU. 474 475 Intel calls this Intel Resource Director Technology 476 (Intel(R) RDT). More information about RDT can be found in the 477 Intel x86 Architecture Software Developer Manual. 478 479 AMD calls this AMD Platform Quality of Service (AMD QoS). 480 More information about AMD QoS can be found in the AMD64 Technology 481 Platform Quality of Service Extensions manual. 482 483 Say N if unsure. 484 485if X86_32 486config X86_BIGSMP 487 bool "Support for big SMP systems with more than 8 CPUs" 488 depends on SMP 489 help 490 This option is needed for the systems that have more than 8 CPUs. 491 492config X86_EXTENDED_PLATFORM 493 bool "Support for extended (non-PC) x86 platforms" 494 default y 495 help 496 If you disable this option then the kernel will only support 497 standard PC platforms. (which covers the vast majority of 498 systems out there.) 499 500 If you enable this option then you'll be able to select support 501 for the following (non-PC) 32 bit x86 platforms: 502 Goldfish (Android emulator) 503 AMD Elan 504 RDC R-321x SoC 505 SGI 320/540 (Visual Workstation) 506 STA2X11-based (e.g. Northville) 507 Moorestown MID devices 508 509 If you have one of these systems, or if you want to build a 510 generic distribution kernel, say Y here - otherwise say N. 511endif 512 513if X86_64 514config X86_EXTENDED_PLATFORM 515 bool "Support for extended (non-PC) x86 platforms" 516 default y 517 help 518 If you disable this option then the kernel will only support 519 standard PC platforms. (which covers the vast majority of 520 systems out there.) 521 522 If you enable this option then you'll be able to select support 523 for the following (non-PC) 64 bit x86 platforms: 524 Numascale NumaChip 525 ScaleMP vSMP 526 SGI Ultraviolet 527 528 If you have one of these systems, or if you want to build a 529 generic distribution kernel, say Y here - otherwise say N. 530endif 531# This is an alphabetically sorted list of 64 bit extended platforms 532# Please maintain the alphabetic order if and when there are additions 533config X86_NUMACHIP 534 bool "Numascale NumaChip" 535 depends on X86_64 536 depends on X86_EXTENDED_PLATFORM 537 depends on NUMA 538 depends on SMP 539 depends on X86_X2APIC 540 depends on PCI_MMCONFIG 541 help 542 Adds support for Numascale NumaChip large-SMP systems. Needed to 543 enable more than ~168 cores. 544 If you don't have one of these, you should say N here. 545 546config X86_VSMP 547 bool "ScaleMP vSMP" 548 select HYPERVISOR_GUEST 549 select PARAVIRT 550 depends on X86_64 && PCI 551 depends on X86_EXTENDED_PLATFORM 552 depends on SMP 553 help 554 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 555 supposed to run on these EM64T-based machines. Only choose this option 556 if you have one of these machines. 557 558config X86_UV 559 bool "SGI Ultraviolet" 560 depends on X86_64 561 depends on X86_EXTENDED_PLATFORM 562 depends on NUMA 563 depends on EFI 564 depends on X86_X2APIC 565 depends on PCI 566 help 567 This option is needed in order to support SGI Ultraviolet systems. 568 If you don't have one of these, you should say N here. 569 570# Following is an alphabetically sorted list of 32 bit extended platforms 571# Please maintain the alphabetic order if and when there are additions 572 573config X86_GOLDFISH 574 bool "Goldfish (Virtual Platform)" 575 depends on X86_EXTENDED_PLATFORM 576 help 577 Enable support for the Goldfish virtual platform used primarily 578 for Android development. Unless you are building for the Android 579 Goldfish emulator say N here. 580 581config X86_INTEL_CE 582 bool "CE4100 TV platform" 583 depends on PCI 584 depends on PCI_GODIRECT 585 depends on X86_IO_APIC 586 depends on X86_32 587 depends on X86_EXTENDED_PLATFORM 588 select X86_REBOOTFIXUPS 589 select OF 590 select OF_EARLY_FLATTREE 591 help 592 Select for the Intel CE media processor (CE4100) SOC. 593 This option compiles in support for the CE4100 SOC for settop 594 boxes and media devices. 595 596config X86_INTEL_MID 597 bool "Intel MID platform support" 598 depends on X86_EXTENDED_PLATFORM 599 depends on X86_PLATFORM_DEVICES 600 depends on PCI 601 depends on X86_64 || (PCI_GOANY && X86_32) 602 depends on X86_IO_APIC 603 select SFI 604 select I2C 605 select DW_APB_TIMER 606 select APB_TIMER 607 select INTEL_SCU_PCI 608 select MFD_INTEL_MSIC 609 help 610 Select to build a kernel capable of supporting Intel MID (Mobile 611 Internet Device) platform systems which do not have the PCI legacy 612 interfaces. If you are building for a PC class system say N here. 613 614 Intel MID platforms are based on an Intel processor and chipset which 615 consume less power than most of the x86 derivatives. 616 617config X86_INTEL_QUARK 618 bool "Intel Quark platform support" 619 depends on X86_32 620 depends on X86_EXTENDED_PLATFORM 621 depends on X86_PLATFORM_DEVICES 622 depends on X86_TSC 623 depends on PCI 624 depends on PCI_GOANY 625 depends on X86_IO_APIC 626 select IOSF_MBI 627 select INTEL_IMR 628 select COMMON_CLK 629 help 630 Select to include support for Quark X1000 SoC. 631 Say Y here if you have a Quark based system such as the Arduino 632 compatible Intel Galileo. 633 634config X86_INTEL_LPSS 635 bool "Intel Low Power Subsystem Support" 636 depends on X86 && ACPI && PCI 637 select COMMON_CLK 638 select PINCTRL 639 select IOSF_MBI 640 help 641 Select to build support for Intel Low Power Subsystem such as 642 found on Intel Lynxpoint PCH. Selecting this option enables 643 things like clock tree (common clock framework) and pincontrol 644 which are needed by the LPSS peripheral drivers. 645 646config X86_AMD_PLATFORM_DEVICE 647 bool "AMD ACPI2Platform devices support" 648 depends on ACPI 649 select COMMON_CLK 650 select PINCTRL 651 help 652 Select to interpret AMD specific ACPI device to platform device 653 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 654 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 655 implemented under PINCTRL subsystem. 656 657config IOSF_MBI 658 tristate "Intel SoC IOSF Sideband support for SoC platforms" 659 depends on PCI 660 help 661 This option enables sideband register access support for Intel SoC 662 platforms. On these platforms the IOSF sideband is used in lieu of 663 MSR's for some register accesses, mostly but not limited to thermal 664 and power. Drivers may query the availability of this device to 665 determine if they need the sideband in order to work on these 666 platforms. The sideband is available on the following SoC products. 667 This list is not meant to be exclusive. 668 - BayTrail 669 - Braswell 670 - Quark 671 672 You should say Y if you are running a kernel on one of these SoC's. 673 674config IOSF_MBI_DEBUG 675 bool "Enable IOSF sideband access through debugfs" 676 depends on IOSF_MBI && DEBUG_FS 677 help 678 Select this option to expose the IOSF sideband access registers (MCR, 679 MDR, MCRX) through debugfs to write and read register information from 680 different units on the SoC. This is most useful for obtaining device 681 state information for debug and analysis. As this is a general access 682 mechanism, users of this option would have specific knowledge of the 683 device they want to access. 684 685 If you don't require the option or are in doubt, say N. 686 687config X86_RDC321X 688 bool "RDC R-321x SoC" 689 depends on X86_32 690 depends on X86_EXTENDED_PLATFORM 691 select M486 692 select X86_REBOOTFIXUPS 693 help 694 This option is needed for RDC R-321x system-on-chip, also known 695 as R-8610-(G). 696 If you don't have one of these chips, you should say N here. 697 698config X86_32_NON_STANDARD 699 bool "Support non-standard 32-bit SMP architectures" 700 depends on X86_32 && SMP 701 depends on X86_EXTENDED_PLATFORM 702 help 703 This option compiles in the bigsmp and STA2X11 default 704 subarchitectures. It is intended for a generic binary 705 kernel. If you select them all, kernel will probe it one by 706 one and will fallback to default. 707 708# Alphabetically sorted list of Non standard 32 bit platforms 709 710config X86_SUPPORTS_MEMORY_FAILURE 711 def_bool y 712 # MCE code calls memory_failure(): 713 depends on X86_MCE 714 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 715 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 716 depends on X86_64 || !SPARSEMEM 717 select ARCH_SUPPORTS_MEMORY_FAILURE 718 719config STA2X11 720 bool "STA2X11 Companion Chip Support" 721 depends on X86_32_NON_STANDARD && PCI 722 select SWIOTLB 723 select MFD_STA2X11 724 select GPIOLIB 725 help 726 This adds support for boards based on the STA2X11 IO-Hub, 727 a.k.a. "ConneXt". The chip is used in place of the standard 728 PC chipset, so all "standard" peripherals are missing. If this 729 option is selected the kernel will still be able to boot on 730 standard PC machines. 731 732config X86_32_IRIS 733 tristate "Eurobraille/Iris poweroff module" 734 depends on X86_32 735 help 736 The Iris machines from EuroBraille do not have APM or ACPI support 737 to shut themselves down properly. A special I/O sequence is 738 needed to do so, which is what this module does at 739 kernel shutdown. 740 741 This is only for Iris machines from EuroBraille. 742 743 If unused, say N. 744 745config SCHED_OMIT_FRAME_POINTER 746 def_bool y 747 prompt "Single-depth WCHAN output" 748 depends on X86 749 help 750 Calculate simpler /proc/<PID>/wchan values. If this option 751 is disabled then wchan values will recurse back to the 752 caller function. This provides more accurate wchan values, 753 at the expense of slightly more scheduling overhead. 754 755 If in doubt, say "Y". 756 757menuconfig HYPERVISOR_GUEST 758 bool "Linux guest support" 759 help 760 Say Y here to enable options for running Linux under various hyper- 761 visors. This option enables basic hypervisor detection and platform 762 setup. 763 764 If you say N, all options in this submenu will be skipped and 765 disabled, and Linux guest support won't be built in. 766 767if HYPERVISOR_GUEST 768 769config PARAVIRT 770 bool "Enable paravirtualization code" 771 help 772 This changes the kernel so it can modify itself when it is run 773 under a hypervisor, potentially improving performance significantly 774 over full virtualization. However, when run without a hypervisor 775 the kernel is theoretically slower and slightly larger. 776 777config PARAVIRT_XXL 778 bool 779 780config PARAVIRT_DEBUG 781 bool "paravirt-ops debugging" 782 depends on PARAVIRT && DEBUG_KERNEL 783 help 784 Enable to debug paravirt_ops internals. Specifically, BUG if 785 a paravirt_op is missing when it is called. 786 787config PARAVIRT_SPINLOCKS 788 bool "Paravirtualization layer for spinlocks" 789 depends on PARAVIRT && SMP 790 help 791 Paravirtualized spinlocks allow a pvops backend to replace the 792 spinlock implementation with something virtualization-friendly 793 (for example, block the virtual CPU rather than spinning). 794 795 It has a minimal impact on native kernels and gives a nice performance 796 benefit on paravirtualized KVM / Xen kernels. 797 798 If you are unsure how to answer this question, answer Y. 799 800config X86_HV_CALLBACK_VECTOR 801 def_bool n 802 803source "arch/x86/xen/Kconfig" 804 805config KVM_GUEST 806 bool "KVM Guest support (including kvmclock)" 807 depends on PARAVIRT 808 select PARAVIRT_CLOCK 809 select ARCH_CPUIDLE_HALTPOLL 810 select X86_HV_CALLBACK_VECTOR 811 default y 812 help 813 This option enables various optimizations for running under the KVM 814 hypervisor. It includes a paravirtualized clock, so that instead 815 of relying on a PIT (or probably other) emulation by the 816 underlying device model, the host provides the guest with 817 timing infrastructure such as time of day, and system time 818 819config ARCH_CPUIDLE_HALTPOLL 820 def_bool n 821 prompt "Disable host haltpoll when loading haltpoll driver" 822 help 823 If virtualized under KVM, disable host haltpoll. 824 825config PVH 826 bool "Support for running PVH guests" 827 help 828 This option enables the PVH entry point for guest virtual machines 829 as specified in the x86/HVM direct boot ABI. 830 831config PARAVIRT_TIME_ACCOUNTING 832 bool "Paravirtual steal time accounting" 833 depends on PARAVIRT 834 help 835 Select this option to enable fine granularity task steal time 836 accounting. Time spent executing other tasks in parallel with 837 the current vCPU is discounted from the vCPU power. To account for 838 that, there can be a small performance impact. 839 840 If in doubt, say N here. 841 842config PARAVIRT_CLOCK 843 bool 844 845config JAILHOUSE_GUEST 846 bool "Jailhouse non-root cell support" 847 depends on X86_64 && PCI 848 select X86_PM_TIMER 849 help 850 This option allows to run Linux as guest in a Jailhouse non-root 851 cell. You can leave this option disabled if you only want to start 852 Jailhouse and run Linux afterwards in the root cell. 853 854config ACRN_GUEST 855 bool "ACRN Guest support" 856 depends on X86_64 857 select X86_HV_CALLBACK_VECTOR 858 help 859 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 860 a flexible, lightweight reference open-source hypervisor, built with 861 real-time and safety-criticality in mind. It is built for embedded 862 IOT with small footprint and real-time features. More details can be 863 found in https://projectacrn.org/. 864 865endif #HYPERVISOR_GUEST 866 867source "arch/x86/Kconfig.cpu" 868 869config HPET_TIMER 870 def_bool X86_64 871 prompt "HPET Timer Support" if X86_32 872 help 873 Use the IA-PC HPET (High Precision Event Timer) to manage 874 time in preference to the PIT and RTC, if a HPET is 875 present. 876 HPET is the next generation timer replacing legacy 8254s. 877 The HPET provides a stable time base on SMP 878 systems, unlike the TSC, but it is more expensive to access, 879 as it is off-chip. The interface used is documented 880 in the HPET spec, revision 1. 881 882 You can safely choose Y here. However, HPET will only be 883 activated if the platform and the BIOS support this feature. 884 Otherwise the 8254 will be used for timing services. 885 886 Choose N to continue using the legacy 8254 timer. 887 888config HPET_EMULATE_RTC 889 def_bool y 890 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 891 892config APB_TIMER 893 def_bool y if X86_INTEL_MID 894 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 895 select DW_APB_TIMER 896 depends on X86_INTEL_MID && SFI 897 help 898 APB timer is the replacement for 8254, HPET on X86 MID platforms. 899 The APBT provides a stable time base on SMP 900 systems, unlike the TSC, but it is more expensive to access, 901 as it is off-chip. APB timers are always running regardless of CPU 902 C states, they are used as per CPU clockevent device when possible. 903 904# Mark as expert because too many people got it wrong. 905# The code disables itself when not needed. 906config DMI 907 default y 908 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 909 bool "Enable DMI scanning" if EXPERT 910 help 911 Enabled scanning of DMI to identify machine quirks. Say Y 912 here unless you have verified that your setup is not 913 affected by entries in the DMI blacklist. Required by PNP 914 BIOS code. 915 916config GART_IOMMU 917 bool "Old AMD GART IOMMU support" 918 select DMA_OPS 919 select IOMMU_HELPER 920 select SWIOTLB 921 depends on X86_64 && PCI && AMD_NB 922 help 923 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 924 GART based hardware IOMMUs. 925 926 The GART supports full DMA access for devices with 32-bit access 927 limitations, on systems with more than 3 GB. This is usually needed 928 for USB, sound, many IDE/SATA chipsets and some other devices. 929 930 Newer systems typically have a modern AMD IOMMU, supported via 931 the CONFIG_AMD_IOMMU=y config option. 932 933 In normal configurations this driver is only active when needed: 934 there's more than 3 GB of memory and the system contains a 935 32-bit limited device. 936 937 If unsure, say Y. 938 939config MAXSMP 940 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 941 depends on X86_64 && SMP && DEBUG_KERNEL 942 select CPUMASK_OFFSTACK 943 help 944 Enable maximum number of CPUS and NUMA Nodes for this architecture. 945 If unsure, say N. 946 947# 948# The maximum number of CPUs supported: 949# 950# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 951# and which can be configured interactively in the 952# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 953# 954# The ranges are different on 32-bit and 64-bit kernels, depending on 955# hardware capabilities and scalability features of the kernel. 956# 957# ( If MAXSMP is enabled we just use the highest possible value and disable 958# interactive configuration. ) 959# 960 961config NR_CPUS_RANGE_BEGIN 962 int 963 default NR_CPUS_RANGE_END if MAXSMP 964 default 1 if !SMP 965 default 2 966 967config NR_CPUS_RANGE_END 968 int 969 depends on X86_32 970 default 64 if SMP && X86_BIGSMP 971 default 8 if SMP && !X86_BIGSMP 972 default 1 if !SMP 973 974config NR_CPUS_RANGE_END 975 int 976 depends on X86_64 977 default 8192 if SMP && CPUMASK_OFFSTACK 978 default 512 if SMP && !CPUMASK_OFFSTACK 979 default 1 if !SMP 980 981config NR_CPUS_DEFAULT 982 int 983 depends on X86_32 984 default 32 if X86_BIGSMP 985 default 8 if SMP 986 default 1 if !SMP 987 988config NR_CPUS_DEFAULT 989 int 990 depends on X86_64 991 default 8192 if MAXSMP 992 default 64 if SMP 993 default 1 if !SMP 994 995config NR_CPUS 996 int "Maximum number of CPUs" if SMP && !MAXSMP 997 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 998 default NR_CPUS_DEFAULT 999 help 1000 This allows you to specify the maximum number of CPUs which this 1001 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1002 supported value is 8192, otherwise the maximum value is 512. The 1003 minimum value which makes sense is 2. 1004 1005 This is purely to save memory: each supported CPU adds about 8KB 1006 to the kernel image. 1007 1008config SCHED_SMT 1009 def_bool y if SMP 1010 1011config SCHED_MC 1012 def_bool y 1013 prompt "Multi-core scheduler support" 1014 depends on SMP 1015 help 1016 Multi-core scheduler support improves the CPU scheduler's decision 1017 making when dealing with multi-core CPU chips at a cost of slightly 1018 increased overhead in some places. If unsure say N here. 1019 1020config SCHED_MC_PRIO 1021 bool "CPU core priorities scheduler support" 1022 depends on SCHED_MC && CPU_SUP_INTEL 1023 select X86_INTEL_PSTATE 1024 select CPU_FREQ 1025 default y 1026 help 1027 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1028 core ordering determined at manufacturing time, which allows 1029 certain cores to reach higher turbo frequencies (when running 1030 single threaded workloads) than others. 1031 1032 Enabling this kernel feature teaches the scheduler about 1033 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1034 scheduler's CPU selection logic accordingly, so that higher 1035 overall system performance can be achieved. 1036 1037 This feature will have no effect on CPUs without this feature. 1038 1039 If unsure say Y here. 1040 1041config UP_LATE_INIT 1042 def_bool y 1043 depends on !SMP && X86_LOCAL_APIC 1044 1045config X86_UP_APIC 1046 bool "Local APIC support on uniprocessors" if !PCI_MSI 1047 default PCI_MSI 1048 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1049 help 1050 A local APIC (Advanced Programmable Interrupt Controller) is an 1051 integrated interrupt controller in the CPU. If you have a single-CPU 1052 system which has a processor with a local APIC, you can say Y here to 1053 enable and use it. If you say Y here even though your machine doesn't 1054 have a local APIC, then the kernel will still run with no slowdown at 1055 all. The local APIC supports CPU-generated self-interrupts (timer, 1056 performance counters), and the NMI watchdog which detects hard 1057 lockups. 1058 1059config X86_UP_IOAPIC 1060 bool "IO-APIC support on uniprocessors" 1061 depends on X86_UP_APIC 1062 help 1063 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1064 SMP-capable replacement for PC-style interrupt controllers. Most 1065 SMP systems and many recent uniprocessor systems have one. 1066 1067 If you have a single-CPU system with an IO-APIC, you can say Y here 1068 to use it. If you say Y here even though your machine doesn't have 1069 an IO-APIC, then the kernel will still run with no slowdown at all. 1070 1071config X86_LOCAL_APIC 1072 def_bool y 1073 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1074 select IRQ_DOMAIN_HIERARCHY 1075 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1076 1077config X86_IO_APIC 1078 def_bool y 1079 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1080 1081config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1082 bool "Reroute for broken boot IRQs" 1083 depends on X86_IO_APIC 1084 help 1085 This option enables a workaround that fixes a source of 1086 spurious interrupts. This is recommended when threaded 1087 interrupt handling is used on systems where the generation of 1088 superfluous "boot interrupts" cannot be disabled. 1089 1090 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1091 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1092 kernel does during interrupt handling). On chipsets where this 1093 boot IRQ generation cannot be disabled, this workaround keeps 1094 the original IRQ line masked so that only the equivalent "boot 1095 IRQ" is delivered to the CPUs. The workaround also tells the 1096 kernel to set up the IRQ handler on the boot IRQ line. In this 1097 way only one interrupt is delivered to the kernel. Otherwise 1098 the spurious second interrupt may cause the kernel to bring 1099 down (vital) interrupt lines. 1100 1101 Only affects "broken" chipsets. Interrupt sharing may be 1102 increased on these systems. 1103 1104config X86_MCE 1105 bool "Machine Check / overheating reporting" 1106 select GENERIC_ALLOCATOR 1107 default y 1108 help 1109 Machine Check support allows the processor to notify the 1110 kernel if it detects a problem (e.g. overheating, data corruption). 1111 The action the kernel takes depends on the severity of the problem, 1112 ranging from warning messages to halting the machine. 1113 1114config X86_MCELOG_LEGACY 1115 bool "Support for deprecated /dev/mcelog character device" 1116 depends on X86_MCE 1117 help 1118 Enable support for /dev/mcelog which is needed by the old mcelog 1119 userspace logging daemon. Consider switching to the new generation 1120 rasdaemon solution. 1121 1122config X86_MCE_INTEL 1123 def_bool y 1124 prompt "Intel MCE features" 1125 depends on X86_MCE && X86_LOCAL_APIC 1126 help 1127 Additional support for intel specific MCE features such as 1128 the thermal monitor. 1129 1130config X86_MCE_AMD 1131 def_bool y 1132 prompt "AMD MCE features" 1133 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1134 help 1135 Additional support for AMD specific MCE features such as 1136 the DRAM Error Threshold. 1137 1138config X86_ANCIENT_MCE 1139 bool "Support for old Pentium 5 / WinChip machine checks" 1140 depends on X86_32 && X86_MCE 1141 help 1142 Include support for machine check handling on old Pentium 5 or WinChip 1143 systems. These typically need to be enabled explicitly on the command 1144 line. 1145 1146config X86_MCE_THRESHOLD 1147 depends on X86_MCE_AMD || X86_MCE_INTEL 1148 def_bool y 1149 1150config X86_MCE_INJECT 1151 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1152 tristate "Machine check injector support" 1153 help 1154 Provide support for injecting machine checks for testing purposes. 1155 If you don't know what a machine check is and you don't do kernel 1156 QA it is safe to say n. 1157 1158config X86_THERMAL_VECTOR 1159 def_bool y 1160 depends on X86_MCE_INTEL 1161 1162source "arch/x86/events/Kconfig" 1163 1164config X86_LEGACY_VM86 1165 bool "Legacy VM86 support" 1166 depends on X86_32 1167 help 1168 This option allows user programs to put the CPU into V8086 1169 mode, which is an 80286-era approximation of 16-bit real mode. 1170 1171 Some very old versions of X and/or vbetool require this option 1172 for user mode setting. Similarly, DOSEMU will use it if 1173 available to accelerate real mode DOS programs. However, any 1174 recent version of DOSEMU, X, or vbetool should be fully 1175 functional even without kernel VM86 support, as they will all 1176 fall back to software emulation. Nevertheless, if you are using 1177 a 16-bit DOS program where 16-bit performance matters, vm86 1178 mode might be faster than emulation and you might want to 1179 enable this option. 1180 1181 Note that any app that works on a 64-bit kernel is unlikely to 1182 need this option, as 64-bit kernels don't, and can't, support 1183 V8086 mode. This option is also unrelated to 16-bit protected 1184 mode and is not needed to run most 16-bit programs under Wine. 1185 1186 Enabling this option increases the complexity of the kernel 1187 and slows down exception handling a tiny bit. 1188 1189 If unsure, say N here. 1190 1191config VM86 1192 bool 1193 default X86_LEGACY_VM86 1194 1195config X86_16BIT 1196 bool "Enable support for 16-bit segments" if EXPERT 1197 default y 1198 depends on MODIFY_LDT_SYSCALL 1199 help 1200 This option is required by programs like Wine to run 16-bit 1201 protected mode legacy code on x86 processors. Disabling 1202 this option saves about 300 bytes on i386, or around 6K text 1203 plus 16K runtime memory on x86-64, 1204 1205config X86_ESPFIX32 1206 def_bool y 1207 depends on X86_16BIT && X86_32 1208 1209config X86_ESPFIX64 1210 def_bool y 1211 depends on X86_16BIT && X86_64 1212 1213config X86_VSYSCALL_EMULATION 1214 bool "Enable vsyscall emulation" if EXPERT 1215 default y 1216 depends on X86_64 1217 help 1218 This enables emulation of the legacy vsyscall page. Disabling 1219 it is roughly equivalent to booting with vsyscall=none, except 1220 that it will also disable the helpful warning if a program 1221 tries to use a vsyscall. With this option set to N, offending 1222 programs will just segfault, citing addresses of the form 1223 0xffffffffff600?00. 1224 1225 This option is required by many programs built before 2013, and 1226 care should be used even with newer programs if set to N. 1227 1228 Disabling this option saves about 7K of kernel size and 1229 possibly 4K of additional runtime pagetable memory. 1230 1231config X86_IOPL_IOPERM 1232 bool "IOPERM and IOPL Emulation" 1233 default y 1234 help 1235 This enables the ioperm() and iopl() syscalls which are necessary 1236 for legacy applications. 1237 1238 Legacy IOPL support is an overbroad mechanism which allows user 1239 space aside of accessing all 65536 I/O ports also to disable 1240 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1241 capabilities and permission from potentially active security 1242 modules. 1243 1244 The emulation restricts the functionality of the syscall to 1245 only allowing the full range I/O port access, but prevents the 1246 ability to disable interrupts from user space which would be 1247 granted if the hardware IOPL mechanism would be used. 1248 1249config TOSHIBA 1250 tristate "Toshiba Laptop support" 1251 depends on X86_32 1252 help 1253 This adds a driver to safely access the System Management Mode of 1254 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1255 not work on models with a Phoenix BIOS. The System Management Mode 1256 is used to set the BIOS and power saving options on Toshiba portables. 1257 1258 For information on utilities to make use of this driver see the 1259 Toshiba Linux utilities web site at: 1260 <http://www.buzzard.org.uk/toshiba/>. 1261 1262 Say Y if you intend to run this kernel on a Toshiba portable. 1263 Say N otherwise. 1264 1265config I8K 1266 tristate "Dell i8k legacy laptop support" 1267 select HWMON 1268 select SENSORS_DELL_SMM 1269 help 1270 This option enables legacy /proc/i8k userspace interface in hwmon 1271 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1272 temperature and allows controlling fan speeds of Dell laptops via 1273 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1274 it reports also power and hotkey status. For fan speed control is 1275 needed userspace package i8kutils. 1276 1277 Say Y if you intend to run this kernel on old Dell laptops or want to 1278 use userspace package i8kutils. 1279 Say N otherwise. 1280 1281config X86_REBOOTFIXUPS 1282 bool "Enable X86 board specific fixups for reboot" 1283 depends on X86_32 1284 help 1285 This enables chipset and/or board specific fixups to be done 1286 in order to get reboot to work correctly. This is only needed on 1287 some combinations of hardware and BIOS. The symptom, for which 1288 this config is intended, is when reboot ends with a stalled/hung 1289 system. 1290 1291 Currently, the only fixup is for the Geode machines using 1292 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1293 1294 Say Y if you want to enable the fixup. Currently, it's safe to 1295 enable this option even if you don't need it. 1296 Say N otherwise. 1297 1298config MICROCODE 1299 bool "CPU microcode loading support" 1300 default y 1301 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1302 help 1303 If you say Y here, you will be able to update the microcode on 1304 Intel and AMD processors. The Intel support is for the IA32 family, 1305 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1306 AMD support is for families 0x10 and later. You will obviously need 1307 the actual microcode binary data itself which is not shipped with 1308 the Linux kernel. 1309 1310 The preferred method to load microcode from a detached initrd is described 1311 in Documentation/x86/microcode.rst. For that you need to enable 1312 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1313 initrd for microcode blobs. 1314 1315 In addition, you can build the microcode into the kernel. For that you 1316 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1317 config option. 1318 1319config MICROCODE_INTEL 1320 bool "Intel microcode loading support" 1321 depends on MICROCODE 1322 default MICROCODE 1323 help 1324 This options enables microcode patch loading support for Intel 1325 processors. 1326 1327 For the current Intel microcode data package go to 1328 <https://downloadcenter.intel.com> and search for 1329 'Linux Processor Microcode Data File'. 1330 1331config MICROCODE_AMD 1332 bool "AMD microcode loading support" 1333 depends on MICROCODE 1334 help 1335 If you select this option, microcode patch loading support for AMD 1336 processors will be enabled. 1337 1338config MICROCODE_OLD_INTERFACE 1339 bool "Ancient loading interface (DEPRECATED)" 1340 default n 1341 depends on MICROCODE 1342 help 1343 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1344 which was used by userspace tools like iucode_tool and microcode.ctl. 1345 It is inadequate because it runs too late to be able to properly 1346 load microcode on a machine and it needs special tools. Instead, you 1347 should've switched to the early loading method with the initrd or 1348 builtin microcode by now: Documentation/x86/microcode.rst 1349 1350config X86_MSR 1351 tristate "/dev/cpu/*/msr - Model-specific register support" 1352 help 1353 This device gives privileged processes access to the x86 1354 Model-Specific Registers (MSRs). It is a character device with 1355 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1356 MSR accesses are directed to a specific CPU on multi-processor 1357 systems. 1358 1359config X86_CPUID 1360 tristate "/dev/cpu/*/cpuid - CPU information support" 1361 help 1362 This device gives processes access to the x86 CPUID instruction to 1363 be executed on a specific processor. It is a character device 1364 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1365 /dev/cpu/31/cpuid. 1366 1367choice 1368 prompt "High Memory Support" 1369 default HIGHMEM4G 1370 depends on X86_32 1371 1372config NOHIGHMEM 1373 bool "off" 1374 help 1375 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1376 However, the address space of 32-bit x86 processors is only 4 1377 Gigabytes large. That means that, if you have a large amount of 1378 physical memory, not all of it can be "permanently mapped" by the 1379 kernel. The physical memory that's not permanently mapped is called 1380 "high memory". 1381 1382 If you are compiling a kernel which will never run on a machine with 1383 more than 1 Gigabyte total physical RAM, answer "off" here (default 1384 choice and suitable for most users). This will result in a "3GB/1GB" 1385 split: 3GB are mapped so that each process sees a 3GB virtual memory 1386 space and the remaining part of the 4GB virtual memory space is used 1387 by the kernel to permanently map as much physical memory as 1388 possible. 1389 1390 If the machine has between 1 and 4 Gigabytes physical RAM, then 1391 answer "4GB" here. 1392 1393 If more than 4 Gigabytes is used then answer "64GB" here. This 1394 selection turns Intel PAE (Physical Address Extension) mode on. 1395 PAE implements 3-level paging on IA32 processors. PAE is fully 1396 supported by Linux, PAE mode is implemented on all recent Intel 1397 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1398 then the kernel will not boot on CPUs that don't support PAE! 1399 1400 The actual amount of total physical memory will either be 1401 auto detected or can be forced by using a kernel command line option 1402 such as "mem=256M". (Try "man bootparam" or see the documentation of 1403 your boot loader (lilo or loadlin) about how to pass options to the 1404 kernel at boot time.) 1405 1406 If unsure, say "off". 1407 1408config HIGHMEM4G 1409 bool "4GB" 1410 help 1411 Select this if you have a 32-bit processor and between 1 and 4 1412 gigabytes of physical RAM. 1413 1414config HIGHMEM64G 1415 bool "64GB" 1416 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1417 select X86_PAE 1418 help 1419 Select this if you have a 32-bit processor and more than 4 1420 gigabytes of physical RAM. 1421 1422endchoice 1423 1424choice 1425 prompt "Memory split" if EXPERT 1426 default VMSPLIT_3G 1427 depends on X86_32 1428 help 1429 Select the desired split between kernel and user memory. 1430 1431 If the address range available to the kernel is less than the 1432 physical memory installed, the remaining memory will be available 1433 as "high memory". Accessing high memory is a little more costly 1434 than low memory, as it needs to be mapped into the kernel first. 1435 Note that increasing the kernel address space limits the range 1436 available to user programs, making the address space there 1437 tighter. Selecting anything other than the default 3G/1G split 1438 will also likely make your kernel incompatible with binary-only 1439 kernel modules. 1440 1441 If you are not absolutely sure what you are doing, leave this 1442 option alone! 1443 1444 config VMSPLIT_3G 1445 bool "3G/1G user/kernel split" 1446 config VMSPLIT_3G_OPT 1447 depends on !X86_PAE 1448 bool "3G/1G user/kernel split (for full 1G low memory)" 1449 config VMSPLIT_2G 1450 bool "2G/2G user/kernel split" 1451 config VMSPLIT_2G_OPT 1452 depends on !X86_PAE 1453 bool "2G/2G user/kernel split (for full 2G low memory)" 1454 config VMSPLIT_1G 1455 bool "1G/3G user/kernel split" 1456endchoice 1457 1458config PAGE_OFFSET 1459 hex 1460 default 0xB0000000 if VMSPLIT_3G_OPT 1461 default 0x80000000 if VMSPLIT_2G 1462 default 0x78000000 if VMSPLIT_2G_OPT 1463 default 0x40000000 if VMSPLIT_1G 1464 default 0xC0000000 1465 depends on X86_32 1466 1467config HIGHMEM 1468 def_bool y 1469 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1470 1471config X86_PAE 1472 bool "PAE (Physical Address Extension) Support" 1473 depends on X86_32 && !HIGHMEM4G 1474 select PHYS_ADDR_T_64BIT 1475 select SWIOTLB 1476 help 1477 PAE is required for NX support, and furthermore enables 1478 larger swapspace support for non-overcommit purposes. It 1479 has the cost of more pagetable lookup overhead, and also 1480 consumes more pagetable space per process. 1481 1482config X86_5LEVEL 1483 bool "Enable 5-level page tables support" 1484 default y 1485 select DYNAMIC_MEMORY_LAYOUT 1486 select SPARSEMEM_VMEMMAP 1487 depends on X86_64 1488 help 1489 5-level paging enables access to larger address space: 1490 upto 128 PiB of virtual address space and 4 PiB of 1491 physical address space. 1492 1493 It will be supported by future Intel CPUs. 1494 1495 A kernel with the option enabled can be booted on machines that 1496 support 4- or 5-level paging. 1497 1498 See Documentation/x86/x86_64/5level-paging.rst for more 1499 information. 1500 1501 Say N if unsure. 1502 1503config X86_DIRECT_GBPAGES 1504 def_bool y 1505 depends on X86_64 1506 help 1507 Certain kernel features effectively disable kernel 1508 linear 1 GB mappings (even if the CPU otherwise 1509 supports them), so don't confuse the user by printing 1510 that we have them enabled. 1511 1512config X86_CPA_STATISTICS 1513 bool "Enable statistic for Change Page Attribute" 1514 depends on DEBUG_FS 1515 help 1516 Expose statistics about the Change Page Attribute mechanism, which 1517 helps to determine the effectiveness of preserving large and huge 1518 page mappings when mapping protections are changed. 1519 1520config AMD_MEM_ENCRYPT 1521 bool "AMD Secure Memory Encryption (SME) support" 1522 depends on X86_64 && CPU_SUP_AMD 1523 select DMA_COHERENT_POOL 1524 select DYNAMIC_PHYSICAL_MASK 1525 select ARCH_USE_MEMREMAP_PROT 1526 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1527 select INSTRUCTION_DECODER 1528 help 1529 Say yes to enable support for the encryption of system memory. 1530 This requires an AMD processor that supports Secure Memory 1531 Encryption (SME). 1532 1533config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1534 bool "Activate AMD Secure Memory Encryption (SME) by default" 1535 default y 1536 depends on AMD_MEM_ENCRYPT 1537 help 1538 Say yes to have system memory encrypted by default if running on 1539 an AMD processor that supports Secure Memory Encryption (SME). 1540 1541 If set to Y, then the encryption of system memory can be 1542 deactivated with the mem_encrypt=off command line option. 1543 1544 If set to N, then the encryption of system memory can be 1545 activated with the mem_encrypt=on command line option. 1546 1547# Common NUMA Features 1548config NUMA 1549 bool "NUMA Memory Allocation and Scheduler Support" 1550 depends on SMP 1551 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1552 default y if X86_BIGSMP 1553 help 1554 Enable NUMA (Non-Uniform Memory Access) support. 1555 1556 The kernel will try to allocate memory used by a CPU on the 1557 local memory controller of the CPU and add some more 1558 NUMA awareness to the kernel. 1559 1560 For 64-bit this is recommended if the system is Intel Core i7 1561 (or later), AMD Opteron, or EM64T NUMA. 1562 1563 For 32-bit this is only needed if you boot a 32-bit 1564 kernel on a 64-bit NUMA platform. 1565 1566 Otherwise, you should say N. 1567 1568config AMD_NUMA 1569 def_bool y 1570 prompt "Old style AMD Opteron NUMA detection" 1571 depends on X86_64 && NUMA && PCI 1572 help 1573 Enable AMD NUMA node topology detection. You should say Y here if 1574 you have a multi processor AMD system. This uses an old method to 1575 read the NUMA configuration directly from the builtin Northbridge 1576 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1577 which also takes priority if both are compiled in. 1578 1579config X86_64_ACPI_NUMA 1580 def_bool y 1581 prompt "ACPI NUMA detection" 1582 depends on X86_64 && NUMA && ACPI && PCI 1583 select ACPI_NUMA 1584 help 1585 Enable ACPI SRAT based node topology detection. 1586 1587config NUMA_EMU 1588 bool "NUMA emulation" 1589 depends on NUMA 1590 help 1591 Enable NUMA emulation. A flat machine will be split 1592 into virtual nodes when booted with "numa=fake=N", where N is the 1593 number of nodes. This is only useful for debugging. 1594 1595config NODES_SHIFT 1596 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1597 range 1 10 1598 default "10" if MAXSMP 1599 default "6" if X86_64 1600 default "3" 1601 depends on NEED_MULTIPLE_NODES 1602 help 1603 Specify the maximum number of NUMA Nodes available on the target 1604 system. Increases memory reserved to accommodate various tables. 1605 1606config ARCH_FLATMEM_ENABLE 1607 def_bool y 1608 depends on X86_32 && !NUMA 1609 1610config ARCH_SPARSEMEM_ENABLE 1611 def_bool y 1612 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1613 select SPARSEMEM_STATIC if X86_32 1614 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1615 1616config ARCH_SPARSEMEM_DEFAULT 1617 def_bool X86_64 || (NUMA && X86_32) 1618 1619config ARCH_SELECT_MEMORY_MODEL 1620 def_bool y 1621 depends on ARCH_SPARSEMEM_ENABLE 1622 1623config ARCH_MEMORY_PROBE 1624 bool "Enable sysfs memory/probe interface" 1625 depends on X86_64 && MEMORY_HOTPLUG 1626 help 1627 This option enables a sysfs memory/probe interface for testing. 1628 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1629 If you are unsure how to answer this question, answer N. 1630 1631config ARCH_PROC_KCORE_TEXT 1632 def_bool y 1633 depends on X86_64 && PROC_KCORE 1634 1635config ILLEGAL_POINTER_VALUE 1636 hex 1637 default 0 if X86_32 1638 default 0xdead000000000000 if X86_64 1639 1640config X86_PMEM_LEGACY_DEVICE 1641 bool 1642 1643config X86_PMEM_LEGACY 1644 tristate "Support non-standard NVDIMMs and ADR protected memory" 1645 depends on PHYS_ADDR_T_64BIT 1646 depends on BLK_DEV 1647 select X86_PMEM_LEGACY_DEVICE 1648 select NUMA_KEEP_MEMINFO if NUMA 1649 select LIBNVDIMM 1650 help 1651 Treat memory marked using the non-standard e820 type of 12 as used 1652 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1653 The kernel will offer these regions to the 'pmem' driver so 1654 they can be used for persistent storage. 1655 1656 Say Y if unsure. 1657 1658config HIGHPTE 1659 bool "Allocate 3rd-level pagetables from highmem" 1660 depends on HIGHMEM 1661 help 1662 The VM uses one page table entry for each page of physical memory. 1663 For systems with a lot of RAM, this can be wasteful of precious 1664 low memory. Setting this option will put user-space page table 1665 entries in high memory. 1666 1667config X86_CHECK_BIOS_CORRUPTION 1668 bool "Check for low memory corruption" 1669 help 1670 Periodically check for memory corruption in low memory, which 1671 is suspected to be caused by BIOS. Even when enabled in the 1672 configuration, it is disabled at runtime. Enable it by 1673 setting "memory_corruption_check=1" on the kernel command 1674 line. By default it scans the low 64k of memory every 60 1675 seconds; see the memory_corruption_check_size and 1676 memory_corruption_check_period parameters in 1677 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1678 1679 When enabled with the default parameters, this option has 1680 almost no overhead, as it reserves a relatively small amount 1681 of memory and scans it infrequently. It both detects corruption 1682 and prevents it from affecting the running system. 1683 1684 It is, however, intended as a diagnostic tool; if repeatable 1685 BIOS-originated corruption always affects the same memory, 1686 you can use memmap= to prevent the kernel from using that 1687 memory. 1688 1689config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1690 bool "Set the default setting of memory_corruption_check" 1691 depends on X86_CHECK_BIOS_CORRUPTION 1692 default y 1693 help 1694 Set whether the default state of memory_corruption_check is 1695 on or off. 1696 1697config X86_RESERVE_LOW 1698 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1699 default 64 1700 range 4 640 1701 help 1702 Specify the amount of low memory to reserve for the BIOS. 1703 1704 The first page contains BIOS data structures that the kernel 1705 must not use, so that page must always be reserved. 1706 1707 By default we reserve the first 64K of physical RAM, as a 1708 number of BIOSes are known to corrupt that memory range 1709 during events such as suspend/resume or monitor cable 1710 insertion, so it must not be used by the kernel. 1711 1712 You can set this to 4 if you are absolutely sure that you 1713 trust the BIOS to get all its memory reservations and usages 1714 right. If you know your BIOS have problems beyond the 1715 default 64K area, you can set this to 640 to avoid using the 1716 entire low memory range. 1717 1718 If you have doubts about the BIOS (e.g. suspend/resume does 1719 not work or there's kernel crashes after certain hardware 1720 hotplug events) then you might want to enable 1721 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1722 typical corruption patterns. 1723 1724 Leave this to the default value of 64 if you are unsure. 1725 1726config MATH_EMULATION 1727 bool 1728 depends on MODIFY_LDT_SYSCALL 1729 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1730 help 1731 Linux can emulate a math coprocessor (used for floating point 1732 operations) if you don't have one. 486DX and Pentium processors have 1733 a math coprocessor built in, 486SX and 386 do not, unless you added 1734 a 487DX or 387, respectively. (The messages during boot time can 1735 give you some hints here ["man dmesg"].) Everyone needs either a 1736 coprocessor or this emulation. 1737 1738 If you don't have a math coprocessor, you need to say Y here; if you 1739 say Y here even though you have a coprocessor, the coprocessor will 1740 be used nevertheless. (This behavior can be changed with the kernel 1741 command line option "no387", which comes handy if your coprocessor 1742 is broken. Try "man bootparam" or see the documentation of your boot 1743 loader (lilo or loadlin) about how to pass options to the kernel at 1744 boot time.) This means that it is a good idea to say Y here if you 1745 intend to use this kernel on different machines. 1746 1747 More information about the internals of the Linux math coprocessor 1748 emulation can be found in <file:arch/x86/math-emu/README>. 1749 1750 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1751 kernel, it won't hurt. 1752 1753config MTRR 1754 def_bool y 1755 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1756 help 1757 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1758 the Memory Type Range Registers (MTRRs) may be used to control 1759 processor access to memory ranges. This is most useful if you have 1760 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1761 allows bus write transfers to be combined into a larger transfer 1762 before bursting over the PCI/AGP bus. This can increase performance 1763 of image write operations 2.5 times or more. Saying Y here creates a 1764 /proc/mtrr file which may be used to manipulate your processor's 1765 MTRRs. Typically the X server should use this. 1766 1767 This code has a reasonably generic interface so that similar 1768 control registers on other processors can be easily supported 1769 as well: 1770 1771 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1772 Registers (ARRs) which provide a similar functionality to MTRRs. For 1773 these, the ARRs are used to emulate the MTRRs. 1774 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1775 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1776 write-combining. All of these processors are supported by this code 1777 and it makes sense to say Y here if you have one of them. 1778 1779 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1780 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1781 can lead to all sorts of problems, so it's good to say Y here. 1782 1783 You can safely say Y even if your machine doesn't have MTRRs, you'll 1784 just add about 9 KB to your kernel. 1785 1786 See <file:Documentation/x86/mtrr.rst> for more information. 1787 1788config MTRR_SANITIZER 1789 def_bool y 1790 prompt "MTRR cleanup support" 1791 depends on MTRR 1792 help 1793 Convert MTRR layout from continuous to discrete, so X drivers can 1794 add writeback entries. 1795 1796 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1797 The largest mtrr entry size for a continuous block can be set with 1798 mtrr_chunk_size. 1799 1800 If unsure, say Y. 1801 1802config MTRR_SANITIZER_ENABLE_DEFAULT 1803 int "MTRR cleanup enable value (0-1)" 1804 range 0 1 1805 default "0" 1806 depends on MTRR_SANITIZER 1807 help 1808 Enable mtrr cleanup default value 1809 1810config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1811 int "MTRR cleanup spare reg num (0-7)" 1812 range 0 7 1813 default "1" 1814 depends on MTRR_SANITIZER 1815 help 1816 mtrr cleanup spare entries default, it can be changed via 1817 mtrr_spare_reg_nr=N on the kernel command line. 1818 1819config X86_PAT 1820 def_bool y 1821 prompt "x86 PAT support" if EXPERT 1822 depends on MTRR 1823 help 1824 Use PAT attributes to setup page level cache control. 1825 1826 PATs are the modern equivalents of MTRRs and are much more 1827 flexible than MTRRs. 1828 1829 Say N here if you see bootup problems (boot crash, boot hang, 1830 spontaneous reboots) or a non-working video driver. 1831 1832 If unsure, say Y. 1833 1834config ARCH_USES_PG_UNCACHED 1835 def_bool y 1836 depends on X86_PAT 1837 1838config ARCH_RANDOM 1839 def_bool y 1840 prompt "x86 architectural random number generator" if EXPERT 1841 help 1842 Enable the x86 architectural RDRAND instruction 1843 (Intel Bull Mountain technology) to generate random numbers. 1844 If supported, this is a high bandwidth, cryptographically 1845 secure hardware random number generator. 1846 1847config X86_SMAP 1848 def_bool y 1849 prompt "Supervisor Mode Access Prevention" if EXPERT 1850 help 1851 Supervisor Mode Access Prevention (SMAP) is a security 1852 feature in newer Intel processors. There is a small 1853 performance cost if this enabled and turned on; there is 1854 also a small increase in the kernel size if this is enabled. 1855 1856 If unsure, say Y. 1857 1858config X86_UMIP 1859 def_bool y 1860 prompt "User Mode Instruction Prevention" if EXPERT 1861 help 1862 User Mode Instruction Prevention (UMIP) is a security feature in 1863 some x86 processors. If enabled, a general protection fault is 1864 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1865 executed in user mode. These instructions unnecessarily expose 1866 information about the hardware state. 1867 1868 The vast majority of applications do not use these instructions. 1869 For the very few that do, software emulation is provided in 1870 specific cases in protected and virtual-8086 modes. Emulated 1871 results are dummy. 1872 1873config X86_INTEL_MEMORY_PROTECTION_KEYS 1874 prompt "Memory Protection Keys" 1875 def_bool y 1876 # Note: only available in 64-bit mode 1877 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1878 select ARCH_USES_HIGH_VMA_FLAGS 1879 select ARCH_HAS_PKEYS 1880 help 1881 Memory Protection Keys provides a mechanism for enforcing 1882 page-based protections, but without requiring modification of the 1883 page tables when an application changes protection domains. 1884 1885 For details, see Documentation/core-api/protection-keys.rst 1886 1887 If unsure, say y. 1888 1889choice 1890 prompt "TSX enable mode" 1891 depends on CPU_SUP_INTEL 1892 default X86_INTEL_TSX_MODE_OFF 1893 help 1894 Intel's TSX (Transactional Synchronization Extensions) feature 1895 allows to optimize locking protocols through lock elision which 1896 can lead to a noticeable performance boost. 1897 1898 On the other hand it has been shown that TSX can be exploited 1899 to form side channel attacks (e.g. TAA) and chances are there 1900 will be more of those attacks discovered in the future. 1901 1902 Therefore TSX is not enabled by default (aka tsx=off). An admin 1903 might override this decision by tsx=on the command line parameter. 1904 Even with TSX enabled, the kernel will attempt to enable the best 1905 possible TAA mitigation setting depending on the microcode available 1906 for the particular machine. 1907 1908 This option allows to set the default tsx mode between tsx=on, =off 1909 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1910 details. 1911 1912 Say off if not sure, auto if TSX is in use but it should be used on safe 1913 platforms or on if TSX is in use and the security aspect of tsx is not 1914 relevant. 1915 1916config X86_INTEL_TSX_MODE_OFF 1917 bool "off" 1918 help 1919 TSX is disabled if possible - equals to tsx=off command line parameter. 1920 1921config X86_INTEL_TSX_MODE_ON 1922 bool "on" 1923 help 1924 TSX is always enabled on TSX capable HW - equals the tsx=on command 1925 line parameter. 1926 1927config X86_INTEL_TSX_MODE_AUTO 1928 bool "auto" 1929 help 1930 TSX is enabled on TSX capable HW that is believed to be safe against 1931 side channel attacks- equals the tsx=auto command line parameter. 1932endchoice 1933 1934config EFI 1935 bool "EFI runtime service support" 1936 depends on ACPI 1937 select UCS2_STRING 1938 select EFI_RUNTIME_WRAPPERS 1939 help 1940 This enables the kernel to use EFI runtime services that are 1941 available (such as the EFI variable services). 1942 1943 This option is only useful on systems that have EFI firmware. 1944 In addition, you should use the latest ELILO loader available 1945 at <http://elilo.sourceforge.net> in order to take advantage 1946 of EFI runtime services. However, even with this option, the 1947 resultant kernel should continue to boot on existing non-EFI 1948 platforms. 1949 1950config EFI_STUB 1951 bool "EFI stub support" 1952 depends on EFI && !X86_USE_3DNOW 1953 depends on $(cc-option,-mabi=ms) || X86_32 1954 select RELOCATABLE 1955 help 1956 This kernel feature allows a bzImage to be loaded directly 1957 by EFI firmware without the use of a bootloader. 1958 1959 See Documentation/admin-guide/efi-stub.rst for more information. 1960 1961config EFI_MIXED 1962 bool "EFI mixed-mode support" 1963 depends on EFI_STUB && X86_64 1964 help 1965 Enabling this feature allows a 64-bit kernel to be booted 1966 on a 32-bit firmware, provided that your CPU supports 64-bit 1967 mode. 1968 1969 Note that it is not possible to boot a mixed-mode enabled 1970 kernel via the EFI boot stub - a bootloader that supports 1971 the EFI handover protocol must be used. 1972 1973 If unsure, say N. 1974 1975source "kernel/Kconfig.hz" 1976 1977config KEXEC 1978 bool "kexec system call" 1979 select KEXEC_CORE 1980 help 1981 kexec is a system call that implements the ability to shutdown your 1982 current kernel, and to start another kernel. It is like a reboot 1983 but it is independent of the system firmware. And like a reboot 1984 you can start any kernel with it, not just Linux. 1985 1986 The name comes from the similarity to the exec system call. 1987 1988 It is an ongoing process to be certain the hardware in a machine 1989 is properly shutdown, so do not be surprised if this code does not 1990 initially work for you. As of this writing the exact hardware 1991 interface is strongly in flux, so no good recommendation can be 1992 made. 1993 1994config KEXEC_FILE 1995 bool "kexec file based system call" 1996 select KEXEC_CORE 1997 select BUILD_BIN2C 1998 depends on X86_64 1999 depends on CRYPTO=y 2000 depends on CRYPTO_SHA256=y 2001 help 2002 This is new version of kexec system call. This system call is 2003 file based and takes file descriptors as system call argument 2004 for kernel and initramfs as opposed to list of segments as 2005 accepted by previous system call. 2006 2007config ARCH_HAS_KEXEC_PURGATORY 2008 def_bool KEXEC_FILE 2009 2010config KEXEC_SIG 2011 bool "Verify kernel signature during kexec_file_load() syscall" 2012 depends on KEXEC_FILE 2013 help 2014 2015 This option makes the kexec_file_load() syscall check for a valid 2016 signature of the kernel image. The image can still be loaded without 2017 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2018 there's a signature that we can check, then it must be valid. 2019 2020 In addition to this option, you need to enable signature 2021 verification for the corresponding kernel image type being 2022 loaded in order for this to work. 2023 2024config KEXEC_SIG_FORCE 2025 bool "Require a valid signature in kexec_file_load() syscall" 2026 depends on KEXEC_SIG 2027 help 2028 This option makes kernel signature verification mandatory for 2029 the kexec_file_load() syscall. 2030 2031config KEXEC_BZIMAGE_VERIFY_SIG 2032 bool "Enable bzImage signature verification support" 2033 depends on KEXEC_SIG 2034 depends on SIGNED_PE_FILE_VERIFICATION 2035 select SYSTEM_TRUSTED_KEYRING 2036 help 2037 Enable bzImage signature verification support. 2038 2039config CRASH_DUMP 2040 bool "kernel crash dumps" 2041 depends on X86_64 || (X86_32 && HIGHMEM) 2042 help 2043 Generate crash dump after being started by kexec. 2044 This should be normally only set in special crash dump kernels 2045 which are loaded in the main kernel with kexec-tools into 2046 a specially reserved region and then later executed after 2047 a crash by kdump/kexec. The crash dump kernel must be compiled 2048 to a memory address not used by the main kernel or BIOS using 2049 PHYSICAL_START, or it must be built as a relocatable image 2050 (CONFIG_RELOCATABLE=y). 2051 For more details see Documentation/admin-guide/kdump/kdump.rst 2052 2053config KEXEC_JUMP 2054 bool "kexec jump" 2055 depends on KEXEC && HIBERNATION 2056 help 2057 Jump between original kernel and kexeced kernel and invoke 2058 code in physical address mode via KEXEC 2059 2060config PHYSICAL_START 2061 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2062 default "0x1000000" 2063 help 2064 This gives the physical address where the kernel is loaded. 2065 2066 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2067 bzImage will decompress itself to above physical address and 2068 run from there. Otherwise, bzImage will run from the address where 2069 it has been loaded by the boot loader and will ignore above physical 2070 address. 2071 2072 In normal kdump cases one does not have to set/change this option 2073 as now bzImage can be compiled as a completely relocatable image 2074 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2075 address. This option is mainly useful for the folks who don't want 2076 to use a bzImage for capturing the crash dump and want to use a 2077 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2078 to be specifically compiled to run from a specific memory area 2079 (normally a reserved region) and this option comes handy. 2080 2081 So if you are using bzImage for capturing the crash dump, 2082 leave the value here unchanged to 0x1000000 and set 2083 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2084 for capturing the crash dump change this value to start of 2085 the reserved region. In other words, it can be set based on 2086 the "X" value as specified in the "crashkernel=YM@XM" 2087 command line boot parameter passed to the panic-ed 2088 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2089 for more details about crash dumps. 2090 2091 Usage of bzImage for capturing the crash dump is recommended as 2092 one does not have to build two kernels. Same kernel can be used 2093 as production kernel and capture kernel. Above option should have 2094 gone away after relocatable bzImage support is introduced. But it 2095 is present because there are users out there who continue to use 2096 vmlinux for dump capture. This option should go away down the 2097 line. 2098 2099 Don't change this unless you know what you are doing. 2100 2101config RELOCATABLE 2102 bool "Build a relocatable kernel" 2103 default y 2104 help 2105 This builds a kernel image that retains relocation information 2106 so it can be loaded someplace besides the default 1MB. 2107 The relocations tend to make the kernel binary about 10% larger, 2108 but are discarded at runtime. 2109 2110 One use is for the kexec on panic case where the recovery kernel 2111 must live at a different physical address than the primary 2112 kernel. 2113 2114 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2115 it has been loaded at and the compile time physical address 2116 (CONFIG_PHYSICAL_START) is used as the minimum location. 2117 2118config RANDOMIZE_BASE 2119 bool "Randomize the address of the kernel image (KASLR)" 2120 depends on RELOCATABLE 2121 default y 2122 help 2123 In support of Kernel Address Space Layout Randomization (KASLR), 2124 this randomizes the physical address at which the kernel image 2125 is decompressed and the virtual address where the kernel 2126 image is mapped, as a security feature that deters exploit 2127 attempts relying on knowledge of the location of kernel 2128 code internals. 2129 2130 On 64-bit, the kernel physical and virtual addresses are 2131 randomized separately. The physical address will be anywhere 2132 between 16MB and the top of physical memory (up to 64TB). The 2133 virtual address will be randomized from 16MB up to 1GB (9 bits 2134 of entropy). Note that this also reduces the memory space 2135 available to kernel modules from 1.5GB to 1GB. 2136 2137 On 32-bit, the kernel physical and virtual addresses are 2138 randomized together. They will be randomized from 16MB up to 2139 512MB (8 bits of entropy). 2140 2141 Entropy is generated using the RDRAND instruction if it is 2142 supported. If RDTSC is supported, its value is mixed into 2143 the entropy pool as well. If neither RDRAND nor RDTSC are 2144 supported, then entropy is read from the i8254 timer. The 2145 usable entropy is limited by the kernel being built using 2146 2GB addressing, and that PHYSICAL_ALIGN must be at a 2147 minimum of 2MB. As a result, only 10 bits of entropy are 2148 theoretically possible, but the implementations are further 2149 limited due to memory layouts. 2150 2151 If unsure, say Y. 2152 2153# Relocation on x86 needs some additional build support 2154config X86_NEED_RELOCS 2155 def_bool y 2156 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2157 2158config PHYSICAL_ALIGN 2159 hex "Alignment value to which kernel should be aligned" 2160 default "0x200000" 2161 range 0x2000 0x1000000 if X86_32 2162 range 0x200000 0x1000000 if X86_64 2163 help 2164 This value puts the alignment restrictions on physical address 2165 where kernel is loaded and run from. Kernel is compiled for an 2166 address which meets above alignment restriction. 2167 2168 If bootloader loads the kernel at a non-aligned address and 2169 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2170 address aligned to above value and run from there. 2171 2172 If bootloader loads the kernel at a non-aligned address and 2173 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2174 load address and decompress itself to the address it has been 2175 compiled for and run from there. The address for which kernel is 2176 compiled already meets above alignment restrictions. Hence the 2177 end result is that kernel runs from a physical address meeting 2178 above alignment restrictions. 2179 2180 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2181 this value must be a multiple of 0x200000. 2182 2183 Don't change this unless you know what you are doing. 2184 2185config DYNAMIC_MEMORY_LAYOUT 2186 bool 2187 help 2188 This option makes base addresses of vmalloc and vmemmap as well as 2189 __PAGE_OFFSET movable during boot. 2190 2191config RANDOMIZE_MEMORY 2192 bool "Randomize the kernel memory sections" 2193 depends on X86_64 2194 depends on RANDOMIZE_BASE 2195 select DYNAMIC_MEMORY_LAYOUT 2196 default RANDOMIZE_BASE 2197 help 2198 Randomizes the base virtual address of kernel memory sections 2199 (physical memory mapping, vmalloc & vmemmap). This security feature 2200 makes exploits relying on predictable memory locations less reliable. 2201 2202 The order of allocations remains unchanged. Entropy is generated in 2203 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2204 configuration have in average 30,000 different possible virtual 2205 addresses for each memory section. 2206 2207 If unsure, say Y. 2208 2209config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2210 hex "Physical memory mapping padding" if EXPERT 2211 depends on RANDOMIZE_MEMORY 2212 default "0xa" if MEMORY_HOTPLUG 2213 default "0x0" 2214 range 0x1 0x40 if MEMORY_HOTPLUG 2215 range 0x0 0x40 2216 help 2217 Define the padding in terabytes added to the existing physical 2218 memory size during kernel memory randomization. It is useful 2219 for memory hotplug support but reduces the entropy available for 2220 address randomization. 2221 2222 If unsure, leave at the default value. 2223 2224config HOTPLUG_CPU 2225 def_bool y 2226 depends on SMP 2227 2228config BOOTPARAM_HOTPLUG_CPU0 2229 bool "Set default setting of cpu0_hotpluggable" 2230 depends on HOTPLUG_CPU 2231 help 2232 Set whether default state of cpu0_hotpluggable is on or off. 2233 2234 Say Y here to enable CPU0 hotplug by default. If this switch 2235 is turned on, there is no need to give cpu0_hotplug kernel 2236 parameter and the CPU0 hotplug feature is enabled by default. 2237 2238 Please note: there are two known CPU0 dependencies if you want 2239 to enable the CPU0 hotplug feature either by this switch or by 2240 cpu0_hotplug kernel parameter. 2241 2242 First, resume from hibernate or suspend always starts from CPU0. 2243 So hibernate and suspend are prevented if CPU0 is offline. 2244 2245 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2246 offline if any interrupt can not migrate out of CPU0. There may 2247 be other CPU0 dependencies. 2248 2249 Please make sure the dependencies are under your control before 2250 you enable this feature. 2251 2252 Say N if you don't want to enable CPU0 hotplug feature by default. 2253 You still can enable the CPU0 hotplug feature at boot by kernel 2254 parameter cpu0_hotplug. 2255 2256config DEBUG_HOTPLUG_CPU0 2257 def_bool n 2258 prompt "Debug CPU0 hotplug" 2259 depends on HOTPLUG_CPU 2260 help 2261 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2262 soon as possible and boots up userspace with CPU0 offlined. User 2263 can online CPU0 back after boot time. 2264 2265 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2266 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2267 compilation or giving cpu0_hotplug kernel parameter at boot. 2268 2269 If unsure, say N. 2270 2271config COMPAT_VDSO 2272 def_bool n 2273 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2274 depends on COMPAT_32 2275 help 2276 Certain buggy versions of glibc will crash if they are 2277 presented with a 32-bit vDSO that is not mapped at the address 2278 indicated in its segment table. 2279 2280 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2281 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2282 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2283 the only released version with the bug, but OpenSUSE 9 2284 contains a buggy "glibc 2.3.2". 2285 2286 The symptom of the bug is that everything crashes on startup, saying: 2287 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2288 2289 Saying Y here changes the default value of the vdso32 boot 2290 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2291 This works around the glibc bug but hurts performance. 2292 2293 If unsure, say N: if you are compiling your own kernel, you 2294 are unlikely to be using a buggy version of glibc. 2295 2296choice 2297 prompt "vsyscall table for legacy applications" 2298 depends on X86_64 2299 default LEGACY_VSYSCALL_XONLY 2300 help 2301 Legacy user code that does not know how to find the vDSO expects 2302 to be able to issue three syscalls by calling fixed addresses in 2303 kernel space. Since this location is not randomized with ASLR, 2304 it can be used to assist security vulnerability exploitation. 2305 2306 This setting can be changed at boot time via the kernel command 2307 line parameter vsyscall=[emulate|xonly|none]. 2308 2309 On a system with recent enough glibc (2.14 or newer) and no 2310 static binaries, you can say None without a performance penalty 2311 to improve security. 2312 2313 If unsure, select "Emulate execution only". 2314 2315 config LEGACY_VSYSCALL_EMULATE 2316 bool "Full emulation" 2317 help 2318 The kernel traps and emulates calls into the fixed vsyscall 2319 address mapping. This makes the mapping non-executable, but 2320 it still contains readable known contents, which could be 2321 used in certain rare security vulnerability exploits. This 2322 configuration is recommended when using legacy userspace 2323 that still uses vsyscalls along with legacy binary 2324 instrumentation tools that require code to be readable. 2325 2326 An example of this type of legacy userspace is running 2327 Pin on an old binary that still uses vsyscalls. 2328 2329 config LEGACY_VSYSCALL_XONLY 2330 bool "Emulate execution only" 2331 help 2332 The kernel traps and emulates calls into the fixed vsyscall 2333 address mapping and does not allow reads. This 2334 configuration is recommended when userspace might use the 2335 legacy vsyscall area but support for legacy binary 2336 instrumentation of legacy code is not needed. It mitigates 2337 certain uses of the vsyscall area as an ASLR-bypassing 2338 buffer. 2339 2340 config LEGACY_VSYSCALL_NONE 2341 bool "None" 2342 help 2343 There will be no vsyscall mapping at all. This will 2344 eliminate any risk of ASLR bypass due to the vsyscall 2345 fixed address mapping. Attempts to use the vsyscalls 2346 will be reported to dmesg, so that either old or 2347 malicious userspace programs can be identified. 2348 2349endchoice 2350 2351config CMDLINE_BOOL 2352 bool "Built-in kernel command line" 2353 help 2354 Allow for specifying boot arguments to the kernel at 2355 build time. On some systems (e.g. embedded ones), it is 2356 necessary or convenient to provide some or all of the 2357 kernel boot arguments with the kernel itself (that is, 2358 to not rely on the boot loader to provide them.) 2359 2360 To compile command line arguments into the kernel, 2361 set this option to 'Y', then fill in the 2362 boot arguments in CONFIG_CMDLINE. 2363 2364 Systems with fully functional boot loaders (i.e. non-embedded) 2365 should leave this option set to 'N'. 2366 2367config CMDLINE 2368 string "Built-in kernel command string" 2369 depends on CMDLINE_BOOL 2370 default "" 2371 help 2372 Enter arguments here that should be compiled into the kernel 2373 image and used at boot time. If the boot loader provides a 2374 command line at boot time, it is appended to this string to 2375 form the full kernel command line, when the system boots. 2376 2377 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2378 change this behavior. 2379 2380 In most cases, the command line (whether built-in or provided 2381 by the boot loader) should specify the device for the root 2382 file system. 2383 2384config CMDLINE_OVERRIDE 2385 bool "Built-in command line overrides boot loader arguments" 2386 depends on CMDLINE_BOOL && CMDLINE != "" 2387 help 2388 Set this option to 'Y' to have the kernel ignore the boot loader 2389 command line, and use ONLY the built-in command line. 2390 2391 This is used to work around broken boot loaders. This should 2392 be set to 'N' under normal conditions. 2393 2394config MODIFY_LDT_SYSCALL 2395 bool "Enable the LDT (local descriptor table)" if EXPERT 2396 default y 2397 help 2398 Linux can allow user programs to install a per-process x86 2399 Local Descriptor Table (LDT) using the modify_ldt(2) system 2400 call. This is required to run 16-bit or segmented code such as 2401 DOSEMU or some Wine programs. It is also used by some very old 2402 threading libraries. 2403 2404 Enabling this feature adds a small amount of overhead to 2405 context switches and increases the low-level kernel attack 2406 surface. Disabling it removes the modify_ldt(2) system call. 2407 2408 Saying 'N' here may make sense for embedded or server kernels. 2409 2410source "kernel/livepatch/Kconfig" 2411 2412endmenu 2413 2414config ARCH_HAS_ADD_PAGES 2415 def_bool y 2416 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2417 2418config ARCH_ENABLE_MEMORY_HOTPLUG 2419 def_bool y 2420 depends on X86_64 || (X86_32 && HIGHMEM) 2421 2422config ARCH_ENABLE_MEMORY_HOTREMOVE 2423 def_bool y 2424 depends on MEMORY_HOTPLUG 2425 2426config USE_PERCPU_NUMA_NODE_ID 2427 def_bool y 2428 depends on NUMA 2429 2430config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2431 def_bool y 2432 depends on X86_64 || X86_PAE 2433 2434config ARCH_ENABLE_HUGEPAGE_MIGRATION 2435 def_bool y 2436 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2437 2438config ARCH_ENABLE_THP_MIGRATION 2439 def_bool y 2440 depends on X86_64 && TRANSPARENT_HUGEPAGE 2441 2442menu "Power management and ACPI options" 2443 2444config ARCH_HIBERNATION_HEADER 2445 def_bool y 2446 depends on HIBERNATION 2447 2448source "kernel/power/Kconfig" 2449 2450source "drivers/acpi/Kconfig" 2451 2452source "drivers/sfi/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 || SFI || 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 select SWIOTLB_XEN 2651 2652config MMCONF_FAM10H 2653 def_bool y 2654 depends on X86_64 && PCI_MMCONFIG && ACPI 2655 2656config PCI_CNB20LE_QUIRK 2657 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2658 depends on PCI 2659 help 2660 Read the PCI windows out of the CNB20LE host bridge. This allows 2661 PCI hotplug to work on systems with the CNB20LE chipset which do 2662 not have ACPI. 2663 2664 There's no public spec for this chipset, and this functionality 2665 is known to be incomplete. 2666 2667 You should say N unless you know you need this. 2668 2669config ISA_BUS 2670 bool "ISA bus support on modern systems" if EXPERT 2671 help 2672 Expose ISA bus device drivers and options available for selection and 2673 configuration. Enable this option if your target machine has an ISA 2674 bus. ISA is an older system, displaced by PCI and newer bus 2675 architectures -- if your target machine is modern, it probably does 2676 not have an ISA bus. 2677 2678 If unsure, say N. 2679 2680# x86_64 have no ISA slots, but can have ISA-style DMA. 2681config ISA_DMA_API 2682 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2683 default y 2684 help 2685 Enables ISA-style DMA support for devices requiring such controllers. 2686 If unsure, say Y. 2687 2688if X86_32 2689 2690config ISA 2691 bool "ISA support" 2692 help 2693 Find out whether you have ISA slots on your motherboard. ISA is the 2694 name of a bus system, i.e. the way the CPU talks to the other stuff 2695 inside your box. Other bus systems are PCI, EISA, MicroChannel 2696 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2697 newer boards don't support it. If you have ISA, say Y, otherwise N. 2698 2699config SCx200 2700 tristate "NatSemi SCx200 support" 2701 help 2702 This provides basic support for National Semiconductor's 2703 (now AMD's) Geode processors. The driver probes for the 2704 PCI-IDs of several on-chip devices, so its a good dependency 2705 for other scx200_* drivers. 2706 2707 If compiled as a module, the driver is named scx200. 2708 2709config SCx200HR_TIMER 2710 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2711 depends on SCx200 2712 default y 2713 help 2714 This driver provides a clocksource built upon the on-chip 2715 27MHz high-resolution timer. Its also a workaround for 2716 NSC Geode SC-1100's buggy TSC, which loses time when the 2717 processor goes idle (as is done by the scheduler). The 2718 other workaround is idle=poll boot option. 2719 2720config OLPC 2721 bool "One Laptop Per Child support" 2722 depends on !X86_PAE 2723 select GPIOLIB 2724 select OF 2725 select OF_PROMTREE 2726 select IRQ_DOMAIN 2727 select OLPC_EC 2728 help 2729 Add support for detecting the unique features of the OLPC 2730 XO hardware. 2731 2732config OLPC_XO1_PM 2733 bool "OLPC XO-1 Power Management" 2734 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2735 help 2736 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2737 2738config OLPC_XO1_RTC 2739 bool "OLPC XO-1 Real Time Clock" 2740 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2741 help 2742 Add support for the XO-1 real time clock, which can be used as a 2743 programmable wakeup source. 2744 2745config OLPC_XO1_SCI 2746 bool "OLPC XO-1 SCI extras" 2747 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2748 depends on INPUT=y 2749 select POWER_SUPPLY 2750 help 2751 Add support for SCI-based features of the OLPC XO-1 laptop: 2752 - EC-driven system wakeups 2753 - Power button 2754 - Ebook switch 2755 - Lid switch 2756 - AC adapter status updates 2757 - Battery status updates 2758 2759config OLPC_XO15_SCI 2760 bool "OLPC XO-1.5 SCI extras" 2761 depends on OLPC && ACPI 2762 select POWER_SUPPLY 2763 help 2764 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2765 - EC-driven system wakeups 2766 - AC adapter status updates 2767 - Battery status updates 2768 2769config ALIX 2770 bool "PCEngines ALIX System Support (LED setup)" 2771 select GPIOLIB 2772 help 2773 This option enables system support for the PCEngines ALIX. 2774 At present this just sets up LEDs for GPIO control on 2775 ALIX2/3/6 boards. However, other system specific setup should 2776 get added here. 2777 2778 Note: You must still enable the drivers for GPIO and LED support 2779 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2780 2781 Note: You have to set alix.force=1 for boards with Award BIOS. 2782 2783config NET5501 2784 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2785 select GPIOLIB 2786 help 2787 This option enables system support for the Soekris Engineering net5501. 2788 2789config GEOS 2790 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2791 select GPIOLIB 2792 depends on DMI 2793 help 2794 This option enables system support for the Traverse Technologies GEOS. 2795 2796config TS5500 2797 bool "Technologic Systems TS-5500 platform support" 2798 depends on MELAN 2799 select CHECK_SIGNATURE 2800 select NEW_LEDS 2801 select LEDS_CLASS 2802 help 2803 This option enables system support for the Technologic Systems TS-5500. 2804 2805endif # X86_32 2806 2807config AMD_NB 2808 def_bool y 2809 depends on CPU_SUP_AMD && PCI 2810 2811config X86_SYSFB 2812 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2813 help 2814 Firmwares often provide initial graphics framebuffers so the BIOS, 2815 bootloader or kernel can show basic video-output during boot for 2816 user-guidance and debugging. Historically, x86 used the VESA BIOS 2817 Extensions and EFI-framebuffers for this, which are mostly limited 2818 to x86. 2819 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2820 framebuffers so the new generic system-framebuffer drivers can be 2821 used on x86. If the framebuffer is not compatible with the generic 2822 modes, it is advertised as fallback platform framebuffer so legacy 2823 drivers like efifb, vesafb and uvesafb can pick it up. 2824 If this option is not selected, all system framebuffers are always 2825 marked as fallback platform framebuffers as usual. 2826 2827 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2828 not be able to pick up generic system framebuffers if this option 2829 is selected. You are highly encouraged to enable simplefb as 2830 replacement if you select this option. simplefb can correctly deal 2831 with generic system framebuffers. But you should still keep vesafb 2832 and others enabled as fallback if a system framebuffer is 2833 incompatible with simplefb. 2834 2835 If unsure, say Y. 2836 2837endmenu 2838 2839 2840menu "Binary Emulations" 2841 2842config IA32_EMULATION 2843 bool "IA32 Emulation" 2844 depends on X86_64 2845 select ARCH_WANT_OLD_COMPAT_IPC 2846 select BINFMT_ELF 2847 select COMPAT_BINFMT_ELF 2848 select COMPAT_OLD_SIGACTION 2849 help 2850 Include code to run legacy 32-bit programs under a 2851 64-bit kernel. You should likely turn this on, unless you're 2852 100% sure that you don't have any 32-bit programs left. 2853 2854config IA32_AOUT 2855 tristate "IA32 a.out support" 2856 depends on IA32_EMULATION 2857 depends on BROKEN 2858 help 2859 Support old a.out binaries in the 32bit emulation. 2860 2861config X86_X32 2862 bool "x32 ABI for 64-bit mode" 2863 depends on X86_64 2864 help 2865 Include code to run binaries for the x32 native 32-bit ABI 2866 for 64-bit processors. An x32 process gets access to the 2867 full 64-bit register file and wide data path while leaving 2868 pointers at 32 bits for smaller memory footprint. 2869 2870 You will need a recent binutils (2.22 or later) with 2871 elf32_x86_64 support enabled to compile a kernel with this 2872 option set. 2873 2874config COMPAT_32 2875 def_bool y 2876 depends on IA32_EMULATION || X86_32 2877 select HAVE_UID16 2878 select OLD_SIGSUSPEND3 2879 2880config COMPAT 2881 def_bool y 2882 depends on IA32_EMULATION || X86_X32 2883 2884if COMPAT 2885config COMPAT_FOR_U64_ALIGNMENT 2886 def_bool y 2887 2888config SYSVIPC_COMPAT 2889 def_bool y 2890 depends on SYSVIPC 2891endif 2892 2893endmenu 2894 2895 2896config HAVE_ATOMIC_IOMAP 2897 def_bool y 2898 depends on X86_32 2899 2900source "drivers/firmware/Kconfig" 2901 2902source "arch/x86/kvm/Kconfig" 2903 2904source "arch/x86/Kconfig.assembler" 2905