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_AOUT 18 select HAVE_GENERIC_DMA_COHERENT 19 select MODULES_USE_ELF_REL 20 select OLD_SIGACTION 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 if (MEMORY_ISOLATION && COMPACTION) || CMA 27 select ARCH_SUPPORTS_INT128 28 select ARCH_USE_CMPXCHG_LOCKREF 29 select HAVE_ARCH_SOFT_DIRTY 30 select MODULES_USE_ELF_RELA 31 select X86_DEV_DMA_OPS 32 33# 34# Arch settings 35# 36# ( Note that options that are marked 'if X86_64' could in principle be 37# ported to 32-bit as well. ) 38# 39config X86 40 def_bool y 41 # 42 # Note: keep this list sorted alphabetically 43 # 44 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 45 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 46 select ANON_INODES 47 select ARCH_CLOCKSOURCE_DATA 48 select ARCH_DISCARD_MEMBLOCK 49 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 50 select ARCH_HAS_DEBUG_VIRTUAL 51 select ARCH_HAS_DEVMEM_IS_ALLOWED 52 select ARCH_HAS_ELF_RANDOMIZE 53 select ARCH_HAS_FAST_MULTIPLIER 54 select ARCH_HAS_FORTIFY_SOURCE 55 select ARCH_HAS_GCOV_PROFILE_ALL 56 select ARCH_HAS_KCOV if X86_64 57 select ARCH_HAS_PHYS_TO_DMA 58 select ARCH_HAS_PMEM_API if X86_64 59 select ARCH_HAS_REFCOUNT 60 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 61 select ARCH_HAS_SET_MEMORY 62 select ARCH_HAS_SG_CHAIN 63 select ARCH_HAS_STRICT_KERNEL_RWX 64 select ARCH_HAS_STRICT_MODULE_RWX 65 select ARCH_HAS_UBSAN_SANITIZE_ALL 66 select ARCH_HAS_ZONE_DEVICE if X86_64 67 select ARCH_HAVE_NMI_SAFE_CMPXCHG 68 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 69 select ARCH_MIGHT_HAVE_PC_PARPORT 70 select ARCH_MIGHT_HAVE_PC_SERIO 71 select ARCH_SUPPORTS_ATOMIC_RMW 72 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 73 select ARCH_USE_BUILTIN_BSWAP 74 select ARCH_USE_QUEUED_RWLOCKS 75 select ARCH_USE_QUEUED_SPINLOCKS 76 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 77 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 78 select ARCH_WANTS_THP_SWAP if X86_64 79 select BUILDTIME_EXTABLE_SORT 80 select CLKEVT_I8253 81 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 82 select CLOCKSOURCE_WATCHDOG 83 select DCACHE_WORD_ACCESS 84 select EDAC_ATOMIC_SCRUB 85 select EDAC_SUPPORT 86 select GENERIC_CLOCKEVENTS 87 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 88 select GENERIC_CLOCKEVENTS_MIN_ADJUST 89 select GENERIC_CMOS_UPDATE 90 select GENERIC_CPU_AUTOPROBE 91 select GENERIC_CPU_VULNERABILITIES 92 select GENERIC_EARLY_IOREMAP 93 select GENERIC_FIND_FIRST_BIT 94 select GENERIC_IOMAP 95 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 96 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 97 select GENERIC_IRQ_MIGRATION if SMP 98 select GENERIC_IRQ_PROBE 99 select GENERIC_IRQ_RESERVATION_MODE 100 select GENERIC_IRQ_SHOW 101 select GENERIC_PENDING_IRQ if SMP 102 select GENERIC_SMP_IDLE_THREAD 103 select GENERIC_STRNCPY_FROM_USER 104 select GENERIC_STRNLEN_USER 105 select GENERIC_TIME_VSYSCALL 106 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 107 select HAVE_ACPI_APEI if ACPI 108 select HAVE_ACPI_APEI_NMI if ACPI 109 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 110 select HAVE_ARCH_AUDITSYSCALL 111 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 112 select HAVE_ARCH_JUMP_LABEL 113 select HAVE_ARCH_KASAN if X86_64 114 select HAVE_ARCH_KGDB 115 select HAVE_ARCH_MMAP_RND_BITS if MMU 116 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 117 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 118 select HAVE_ARCH_SECCOMP_FILTER 119 select HAVE_ARCH_TRACEHOOK 120 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 121 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 122 select HAVE_ARCH_VMAP_STACK if X86_64 123 select HAVE_ARCH_WITHIN_STACK_FRAMES 124 select HAVE_CC_STACKPROTECTOR 125 select HAVE_CMPXCHG_DOUBLE 126 select HAVE_CMPXCHG_LOCAL 127 select HAVE_CONTEXT_TRACKING if X86_64 128 select HAVE_COPY_THREAD_TLS 129 select HAVE_C_RECORDMCOUNT 130 select HAVE_DEBUG_KMEMLEAK 131 select HAVE_DEBUG_STACKOVERFLOW 132 select HAVE_DMA_API_DEBUG 133 select HAVE_DMA_CONTIGUOUS 134 select HAVE_DYNAMIC_FTRACE 135 select HAVE_DYNAMIC_FTRACE_WITH_REGS 136 select HAVE_EBPF_JIT if X86_64 137 select HAVE_EFFICIENT_UNALIGNED_ACCESS 138 select HAVE_EXIT_THREAD 139 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 140 select HAVE_FTRACE_MCOUNT_RECORD 141 select HAVE_FUNCTION_GRAPH_TRACER 142 select HAVE_FUNCTION_TRACER 143 select HAVE_GCC_PLUGINS 144 select HAVE_HW_BREAKPOINT 145 select HAVE_IDE 146 select HAVE_IOREMAP_PROT 147 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 148 select HAVE_IRQ_TIME_ACCOUNTING 149 select HAVE_KERNEL_BZIP2 150 select HAVE_KERNEL_GZIP 151 select HAVE_KERNEL_LZ4 152 select HAVE_KERNEL_LZMA 153 select HAVE_KERNEL_LZO 154 select HAVE_KERNEL_XZ 155 select HAVE_KPROBES 156 select HAVE_KPROBES_ON_FTRACE 157 select HAVE_FUNCTION_ERROR_INJECTION 158 select HAVE_KRETPROBES 159 select HAVE_KVM 160 select HAVE_LIVEPATCH if X86_64 161 select HAVE_MEMBLOCK 162 select HAVE_MEMBLOCK_NODE_MAP 163 select HAVE_MIXED_BREAKPOINTS_REGS 164 select HAVE_MOD_ARCH_SPECIFIC 165 select HAVE_NMI 166 select HAVE_OPROFILE 167 select HAVE_OPTPROBES 168 select HAVE_PCSPKR_PLATFORM 169 select HAVE_PERF_EVENTS 170 select HAVE_PERF_EVENTS_NMI 171 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 172 select HAVE_PERF_REGS 173 select HAVE_PERF_USER_STACK_DUMP 174 select HAVE_RCU_TABLE_FREE 175 select HAVE_REGS_AND_STACK_ACCESS_API 176 select HAVE_RELIABLE_STACKTRACE if X86_64 && UNWINDER_FRAME_POINTER && STACK_VALIDATION 177 select HAVE_STACK_VALIDATION if X86_64 178 select HAVE_SYSCALL_TRACEPOINTS 179 select HAVE_UNSTABLE_SCHED_CLOCK 180 select HAVE_USER_RETURN_NOTIFIER 181 select IRQ_FORCED_THREADING 182 select PCI_LOCKLESS_CONFIG 183 select PERF_EVENTS 184 select RTC_LIB 185 select RTC_MC146818_LIB 186 select SPARSE_IRQ 187 select SRCU 188 select SYSCTL_EXCEPTION_TRACE 189 select THREAD_INFO_IN_TASK 190 select USER_STACKTRACE_SUPPORT 191 select VIRT_TO_BUS 192 select X86_FEATURE_NAMES if PROC_FS 193 194config INSTRUCTION_DECODER 195 def_bool y 196 depends on KPROBES || PERF_EVENTS || UPROBES 197 198config OUTPUT_FORMAT 199 string 200 default "elf32-i386" if X86_32 201 default "elf64-x86-64" if X86_64 202 203config ARCH_DEFCONFIG 204 string 205 default "arch/x86/configs/i386_defconfig" if X86_32 206 default "arch/x86/configs/x86_64_defconfig" if X86_64 207 208config LOCKDEP_SUPPORT 209 def_bool y 210 211config STACKTRACE_SUPPORT 212 def_bool y 213 214config MMU 215 def_bool y 216 217config ARCH_MMAP_RND_BITS_MIN 218 default 28 if 64BIT 219 default 8 220 221config ARCH_MMAP_RND_BITS_MAX 222 default 32 if 64BIT 223 default 16 224 225config ARCH_MMAP_RND_COMPAT_BITS_MIN 226 default 8 227 228config ARCH_MMAP_RND_COMPAT_BITS_MAX 229 default 16 230 231config SBUS 232 bool 233 234config NEED_DMA_MAP_STATE 235 def_bool y 236 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB 237 238config NEED_SG_DMA_LENGTH 239 def_bool y 240 241config GENERIC_ISA_DMA 242 def_bool y 243 depends on ISA_DMA_API 244 245config GENERIC_BUG 246 def_bool y 247 depends on BUG 248 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 249 250config GENERIC_BUG_RELATIVE_POINTERS 251 bool 252 253config GENERIC_HWEIGHT 254 def_bool y 255 256config ARCH_MAY_HAVE_PC_FDC 257 def_bool y 258 depends on ISA_DMA_API 259 260config RWSEM_XCHGADD_ALGORITHM 261 def_bool y 262 263config GENERIC_CALIBRATE_DELAY 264 def_bool y 265 266config ARCH_HAS_CPU_RELAX 267 def_bool y 268 269config ARCH_HAS_CACHE_LINE_SIZE 270 def_bool y 271 272config HAVE_SETUP_PER_CPU_AREA 273 def_bool y 274 275config NEED_PER_CPU_EMBED_FIRST_CHUNK 276 def_bool y 277 278config NEED_PER_CPU_PAGE_FIRST_CHUNK 279 def_bool y 280 281config ARCH_HIBERNATION_POSSIBLE 282 def_bool y 283 284config ARCH_SUSPEND_POSSIBLE 285 def_bool y 286 287config ARCH_WANT_HUGE_PMD_SHARE 288 def_bool y 289 290config ARCH_WANT_GENERAL_HUGETLB 291 def_bool y 292 293config ZONE_DMA32 294 def_bool y if X86_64 295 296config AUDIT_ARCH 297 def_bool y if X86_64 298 299config ARCH_SUPPORTS_OPTIMIZED_INLINING 300 def_bool y 301 302config ARCH_SUPPORTS_DEBUG_PAGEALLOC 303 def_bool y 304 305config KASAN_SHADOW_OFFSET 306 hex 307 depends on KASAN 308 default 0xdffffc0000000000 309 310config HAVE_INTEL_TXT 311 def_bool y 312 depends on INTEL_IOMMU && ACPI 313 314config X86_32_SMP 315 def_bool y 316 depends on X86_32 && SMP 317 318config X86_64_SMP 319 def_bool y 320 depends on X86_64 && SMP 321 322config X86_32_LAZY_GS 323 def_bool y 324 depends on X86_32 && !CC_STACKPROTECTOR 325 326config ARCH_SUPPORTS_UPROBES 327 def_bool y 328 329config FIX_EARLYCON_MEM 330 def_bool y 331 332config PGTABLE_LEVELS 333 int 334 default 5 if X86_5LEVEL 335 default 4 if X86_64 336 default 3 if X86_PAE 337 default 2 338 339source "init/Kconfig" 340source "kernel/Kconfig.freezer" 341 342menu "Processor type and features" 343 344config ZONE_DMA 345 bool "DMA memory allocation support" if EXPERT 346 default y 347 help 348 DMA memory allocation support allows devices with less than 32-bit 349 addressing to allocate within the first 16MB of address space. 350 Disable if no such devices will be used. 351 352 If unsure, say Y. 353 354config SMP 355 bool "Symmetric multi-processing support" 356 ---help--- 357 This enables support for systems with more than one CPU. If you have 358 a system with only one CPU, say N. If you have a system with more 359 than one CPU, say Y. 360 361 If you say N here, the kernel will run on uni- and multiprocessor 362 machines, but will use only one CPU of a multiprocessor machine. If 363 you say Y here, the kernel will run on many, but not all, 364 uniprocessor machines. On a uniprocessor machine, the kernel 365 will run faster if you say N here. 366 367 Note that if you say Y here and choose architecture "586" or 368 "Pentium" under "Processor family", the kernel will not work on 486 369 architectures. Similarly, multiprocessor kernels for the "PPro" 370 architecture may not work on all Pentium based boards. 371 372 People using multiprocessor machines who say Y here should also say 373 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 374 Management" code will be disabled if you say Y here. 375 376 See also <file:Documentation/x86/i386/IO-APIC.txt>, 377 <file:Documentation/lockup-watchdogs.txt> and the SMP-HOWTO available at 378 <http://www.tldp.org/docs.html#howto>. 379 380 If you don't know what to do here, say N. 381 382config X86_FEATURE_NAMES 383 bool "Processor feature human-readable names" if EMBEDDED 384 default y 385 ---help--- 386 This option compiles in a table of x86 feature bits and corresponding 387 names. This is required to support /proc/cpuinfo and a few kernel 388 messages. You can disable this to save space, at the expense of 389 making those few kernel messages show numeric feature bits instead. 390 391 If in doubt, say Y. 392 393config X86_FAST_FEATURE_TESTS 394 bool "Fast CPU feature tests" if EMBEDDED 395 default y 396 ---help--- 397 Some fast-paths in the kernel depend on the capabilities of the CPU. 398 Say Y here for the kernel to patch in the appropriate code at runtime 399 based on the capabilities of the CPU. The infrastructure for patching 400 code at runtime takes up some additional space; space-constrained 401 embedded systems may wish to say N here to produce smaller, slightly 402 slower code. 403 404config X86_X2APIC 405 bool "Support x2apic" 406 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 407 ---help--- 408 This enables x2apic support on CPUs that have this feature. 409 410 This allows 32-bit apic IDs (so it can support very large systems), 411 and accesses the local apic via MSRs not via mmio. 412 413 If you don't know what to do here, say N. 414 415config X86_MPPARSE 416 bool "Enable MPS table" if ACPI || SFI 417 default y 418 depends on X86_LOCAL_APIC 419 ---help--- 420 For old smp systems that do not have proper acpi support. Newer systems 421 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 422 423config X86_BIGSMP 424 bool "Support for big SMP systems with more than 8 CPUs" 425 depends on X86_32 && SMP 426 ---help--- 427 This option is needed for the systems that have more than 8 CPUs 428 429config GOLDFISH 430 def_bool y 431 depends on X86_GOLDFISH 432 433config RETPOLINE 434 bool "Avoid speculative indirect branches in kernel" 435 default y 436 help 437 Compile kernel with the retpoline compiler options to guard against 438 kernel-to-user data leaks by avoiding speculative indirect 439 branches. Requires a compiler with -mindirect-branch=thunk-extern 440 support for full protection. The kernel may run slower. 441 442 Without compiler support, at least indirect branches in assembler 443 code are eliminated. Since this includes the syscall entry path, 444 it is not entirely pointless. 445 446config INTEL_RDT 447 bool "Intel Resource Director Technology support" 448 default n 449 depends on X86 && CPU_SUP_INTEL 450 select KERNFS 451 help 452 Select to enable resource allocation and monitoring which are 453 sub-features of Intel Resource Director Technology(RDT). More 454 information about RDT can be found in the Intel x86 455 Architecture Software Developer Manual. 456 457 Say N if unsure. 458 459if X86_32 460config X86_EXTENDED_PLATFORM 461 bool "Support for extended (non-PC) x86 platforms" 462 default y 463 ---help--- 464 If you disable this option then the kernel will only support 465 standard PC platforms. (which covers the vast majority of 466 systems out there.) 467 468 If you enable this option then you'll be able to select support 469 for the following (non-PC) 32 bit x86 platforms: 470 Goldfish (Android emulator) 471 AMD Elan 472 RDC R-321x SoC 473 SGI 320/540 (Visual Workstation) 474 STA2X11-based (e.g. Northville) 475 Moorestown MID devices 476 477 If you have one of these systems, or if you want to build a 478 generic distribution kernel, say Y here - otherwise say N. 479endif 480 481if X86_64 482config X86_EXTENDED_PLATFORM 483 bool "Support for extended (non-PC) x86 platforms" 484 default y 485 ---help--- 486 If you disable this option then the kernel will only support 487 standard PC platforms. (which covers the vast majority of 488 systems out there.) 489 490 If you enable this option then you'll be able to select support 491 for the following (non-PC) 64 bit x86 platforms: 492 Numascale NumaChip 493 ScaleMP vSMP 494 SGI Ultraviolet 495 496 If you have one of these systems, or if you want to build a 497 generic distribution kernel, say Y here - otherwise say N. 498endif 499# This is an alphabetically sorted list of 64 bit extended platforms 500# Please maintain the alphabetic order if and when there are additions 501config X86_NUMACHIP 502 bool "Numascale NumaChip" 503 depends on X86_64 504 depends on X86_EXTENDED_PLATFORM 505 depends on NUMA 506 depends on SMP 507 depends on X86_X2APIC 508 depends on PCI_MMCONFIG 509 ---help--- 510 Adds support for Numascale NumaChip large-SMP systems. Needed to 511 enable more than ~168 cores. 512 If you don't have one of these, you should say N here. 513 514config X86_VSMP 515 bool "ScaleMP vSMP" 516 select HYPERVISOR_GUEST 517 select PARAVIRT 518 depends on X86_64 && PCI 519 depends on X86_EXTENDED_PLATFORM 520 depends on SMP 521 ---help--- 522 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 523 supposed to run on these EM64T-based machines. Only choose this option 524 if you have one of these machines. 525 526config X86_UV 527 bool "SGI Ultraviolet" 528 depends on X86_64 529 depends on X86_EXTENDED_PLATFORM 530 depends on NUMA 531 depends on EFI 532 depends on X86_X2APIC 533 depends on PCI 534 ---help--- 535 This option is needed in order to support SGI Ultraviolet systems. 536 If you don't have one of these, you should say N here. 537 538# Following is an alphabetically sorted list of 32 bit extended platforms 539# Please maintain the alphabetic order if and when there are additions 540 541config X86_GOLDFISH 542 bool "Goldfish (Virtual Platform)" 543 depends on X86_EXTENDED_PLATFORM 544 ---help--- 545 Enable support for the Goldfish virtual platform used primarily 546 for Android development. Unless you are building for the Android 547 Goldfish emulator say N here. 548 549config X86_INTEL_CE 550 bool "CE4100 TV platform" 551 depends on PCI 552 depends on PCI_GODIRECT 553 depends on X86_IO_APIC 554 depends on X86_32 555 depends on X86_EXTENDED_PLATFORM 556 select X86_REBOOTFIXUPS 557 select OF 558 select OF_EARLY_FLATTREE 559 ---help--- 560 Select for the Intel CE media processor (CE4100) SOC. 561 This option compiles in support for the CE4100 SOC for settop 562 boxes and media devices. 563 564config X86_INTEL_MID 565 bool "Intel MID platform support" 566 depends on X86_EXTENDED_PLATFORM 567 depends on X86_PLATFORM_DEVICES 568 depends on PCI 569 depends on X86_64 || (PCI_GOANY && X86_32) 570 depends on X86_IO_APIC 571 select SFI 572 select I2C 573 select DW_APB_TIMER 574 select APB_TIMER 575 select INTEL_SCU_IPC 576 select MFD_INTEL_MSIC 577 ---help--- 578 Select to build a kernel capable of supporting Intel MID (Mobile 579 Internet Device) platform systems which do not have the PCI legacy 580 interfaces. If you are building for a PC class system say N here. 581 582 Intel MID platforms are based on an Intel processor and chipset which 583 consume less power than most of the x86 derivatives. 584 585config X86_INTEL_QUARK 586 bool "Intel Quark platform support" 587 depends on X86_32 588 depends on X86_EXTENDED_PLATFORM 589 depends on X86_PLATFORM_DEVICES 590 depends on X86_TSC 591 depends on PCI 592 depends on PCI_GOANY 593 depends on X86_IO_APIC 594 select IOSF_MBI 595 select INTEL_IMR 596 select COMMON_CLK 597 ---help--- 598 Select to include support for Quark X1000 SoC. 599 Say Y here if you have a Quark based system such as the Arduino 600 compatible Intel Galileo. 601 602config X86_INTEL_LPSS 603 bool "Intel Low Power Subsystem Support" 604 depends on X86 && ACPI 605 select COMMON_CLK 606 select PINCTRL 607 select IOSF_MBI 608 ---help--- 609 Select to build support for Intel Low Power Subsystem such as 610 found on Intel Lynxpoint PCH. Selecting this option enables 611 things like clock tree (common clock framework) and pincontrol 612 which are needed by the LPSS peripheral drivers. 613 614config X86_AMD_PLATFORM_DEVICE 615 bool "AMD ACPI2Platform devices support" 616 depends on ACPI 617 select COMMON_CLK 618 select PINCTRL 619 ---help--- 620 Select to interpret AMD specific ACPI device to platform device 621 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 622 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 623 implemented under PINCTRL subsystem. 624 625config IOSF_MBI 626 tristate "Intel SoC IOSF Sideband support for SoC platforms" 627 depends on PCI 628 ---help--- 629 This option enables sideband register access support for Intel SoC 630 platforms. On these platforms the IOSF sideband is used in lieu of 631 MSR's for some register accesses, mostly but not limited to thermal 632 and power. Drivers may query the availability of this device to 633 determine if they need the sideband in order to work on these 634 platforms. The sideband is available on the following SoC products. 635 This list is not meant to be exclusive. 636 - BayTrail 637 - Braswell 638 - Quark 639 640 You should say Y if you are running a kernel on one of these SoC's. 641 642config IOSF_MBI_DEBUG 643 bool "Enable IOSF sideband access through debugfs" 644 depends on IOSF_MBI && DEBUG_FS 645 ---help--- 646 Select this option to expose the IOSF sideband access registers (MCR, 647 MDR, MCRX) through debugfs to write and read register information from 648 different units on the SoC. This is most useful for obtaining device 649 state information for debug and analysis. As this is a general access 650 mechanism, users of this option would have specific knowledge of the 651 device they want to access. 652 653 If you don't require the option or are in doubt, say N. 654 655config X86_RDC321X 656 bool "RDC R-321x SoC" 657 depends on X86_32 658 depends on X86_EXTENDED_PLATFORM 659 select M486 660 select X86_REBOOTFIXUPS 661 ---help--- 662 This option is needed for RDC R-321x system-on-chip, also known 663 as R-8610-(G). 664 If you don't have one of these chips, you should say N here. 665 666config X86_32_NON_STANDARD 667 bool "Support non-standard 32-bit SMP architectures" 668 depends on X86_32 && SMP 669 depends on X86_EXTENDED_PLATFORM 670 ---help--- 671 This option compiles in the bigsmp and STA2X11 default 672 subarchitectures. It is intended for a generic binary 673 kernel. If you select them all, kernel will probe it one by 674 one and will fallback to default. 675 676# Alphabetically sorted list of Non standard 32 bit platforms 677 678config X86_SUPPORTS_MEMORY_FAILURE 679 def_bool y 680 # MCE code calls memory_failure(): 681 depends on X86_MCE 682 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 683 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 684 depends on X86_64 || !SPARSEMEM 685 select ARCH_SUPPORTS_MEMORY_FAILURE 686 687config STA2X11 688 bool "STA2X11 Companion Chip Support" 689 depends on X86_32_NON_STANDARD && PCI 690 select X86_DEV_DMA_OPS 691 select X86_DMA_REMAP 692 select SWIOTLB 693 select MFD_STA2X11 694 select GPIOLIB 695 default n 696 ---help--- 697 This adds support for boards based on the STA2X11 IO-Hub, 698 a.k.a. "ConneXt". The chip is used in place of the standard 699 PC chipset, so all "standard" peripherals are missing. If this 700 option is selected the kernel will still be able to boot on 701 standard PC machines. 702 703config X86_32_IRIS 704 tristate "Eurobraille/Iris poweroff module" 705 depends on X86_32 706 ---help--- 707 The Iris machines from EuroBraille do not have APM or ACPI support 708 to shut themselves down properly. A special I/O sequence is 709 needed to do so, which is what this module does at 710 kernel shutdown. 711 712 This is only for Iris machines from EuroBraille. 713 714 If unused, say N. 715 716config SCHED_OMIT_FRAME_POINTER 717 def_bool y 718 prompt "Single-depth WCHAN output" 719 depends on X86 720 ---help--- 721 Calculate simpler /proc/<PID>/wchan values. If this option 722 is disabled then wchan values will recurse back to the 723 caller function. This provides more accurate wchan values, 724 at the expense of slightly more scheduling overhead. 725 726 If in doubt, say "Y". 727 728menuconfig HYPERVISOR_GUEST 729 bool "Linux guest support" 730 ---help--- 731 Say Y here to enable options for running Linux under various hyper- 732 visors. This option enables basic hypervisor detection and platform 733 setup. 734 735 If you say N, all options in this submenu will be skipped and 736 disabled, and Linux guest support won't be built in. 737 738if HYPERVISOR_GUEST 739 740config PARAVIRT 741 bool "Enable paravirtualization code" 742 ---help--- 743 This changes the kernel so it can modify itself when it is run 744 under a hypervisor, potentially improving performance significantly 745 over full virtualization. However, when run without a hypervisor 746 the kernel is theoretically slower and slightly larger. 747 748config PARAVIRT_DEBUG 749 bool "paravirt-ops debugging" 750 depends on PARAVIRT && DEBUG_KERNEL 751 ---help--- 752 Enable to debug paravirt_ops internals. Specifically, BUG if 753 a paravirt_op is missing when it is called. 754 755config PARAVIRT_SPINLOCKS 756 bool "Paravirtualization layer for spinlocks" 757 depends on PARAVIRT && SMP 758 ---help--- 759 Paravirtualized spinlocks allow a pvops backend to replace the 760 spinlock implementation with something virtualization-friendly 761 (for example, block the virtual CPU rather than spinning). 762 763 It has a minimal impact on native kernels and gives a nice performance 764 benefit on paravirtualized KVM / Xen kernels. 765 766 If you are unsure how to answer this question, answer Y. 767 768config QUEUED_LOCK_STAT 769 bool "Paravirt queued spinlock statistics" 770 depends on PARAVIRT_SPINLOCKS && DEBUG_FS 771 ---help--- 772 Enable the collection of statistical data on the slowpath 773 behavior of paravirtualized queued spinlocks and report 774 them on debugfs. 775 776source "arch/x86/xen/Kconfig" 777 778config KVM_GUEST 779 bool "KVM Guest support (including kvmclock)" 780 depends on PARAVIRT 781 select PARAVIRT_CLOCK 782 default y 783 ---help--- 784 This option enables various optimizations for running under the KVM 785 hypervisor. It includes a paravirtualized clock, so that instead 786 of relying on a PIT (or probably other) emulation by the 787 underlying device model, the host provides the guest with 788 timing infrastructure such as time of day, and system time 789 790config KVM_DEBUG_FS 791 bool "Enable debug information for KVM Guests in debugfs" 792 depends on KVM_GUEST && DEBUG_FS 793 default n 794 ---help--- 795 This option enables collection of various statistics for KVM guest. 796 Statistics are displayed in debugfs filesystem. Enabling this option 797 may incur significant overhead. 798 799config PARAVIRT_TIME_ACCOUNTING 800 bool "Paravirtual steal time accounting" 801 depends on PARAVIRT 802 default n 803 ---help--- 804 Select this option to enable fine granularity task steal time 805 accounting. Time spent executing other tasks in parallel with 806 the current vCPU is discounted from the vCPU power. To account for 807 that, there can be a small performance impact. 808 809 If in doubt, say N here. 810 811config PARAVIRT_CLOCK 812 bool 813 814config JAILHOUSE_GUEST 815 bool "Jailhouse non-root cell support" 816 depends on X86_64 && PCI 817 select X86_PM_TIMER 818 ---help--- 819 This option allows to run Linux as guest in a Jailhouse non-root 820 cell. You can leave this option disabled if you only want to start 821 Jailhouse and run Linux afterwards in the root cell. 822 823endif #HYPERVISOR_GUEST 824 825config NO_BOOTMEM 826 def_bool y 827 828source "arch/x86/Kconfig.cpu" 829 830config HPET_TIMER 831 def_bool X86_64 832 prompt "HPET Timer Support" if X86_32 833 ---help--- 834 Use the IA-PC HPET (High Precision Event Timer) to manage 835 time in preference to the PIT and RTC, if a HPET is 836 present. 837 HPET is the next generation timer replacing legacy 8254s. 838 The HPET provides a stable time base on SMP 839 systems, unlike the TSC, but it is more expensive to access, 840 as it is off-chip. The interface used is documented 841 in the HPET spec, revision 1. 842 843 You can safely choose Y here. However, HPET will only be 844 activated if the platform and the BIOS support this feature. 845 Otherwise the 8254 will be used for timing services. 846 847 Choose N to continue using the legacy 8254 timer. 848 849config HPET_EMULATE_RTC 850 def_bool y 851 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 852 853config APB_TIMER 854 def_bool y if X86_INTEL_MID 855 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 856 select DW_APB_TIMER 857 depends on X86_INTEL_MID && SFI 858 help 859 APB timer is the replacement for 8254, HPET on X86 MID platforms. 860 The APBT provides a stable time base on SMP 861 systems, unlike the TSC, but it is more expensive to access, 862 as it is off-chip. APB timers are always running regardless of CPU 863 C states, they are used as per CPU clockevent device when possible. 864 865# Mark as expert because too many people got it wrong. 866# The code disables itself when not needed. 867config DMI 868 default y 869 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 870 bool "Enable DMI scanning" if EXPERT 871 ---help--- 872 Enabled scanning of DMI to identify machine quirks. Say Y 873 here unless you have verified that your setup is not 874 affected by entries in the DMI blacklist. Required by PNP 875 BIOS code. 876 877config GART_IOMMU 878 bool "Old AMD GART IOMMU support" 879 select SWIOTLB 880 depends on X86_64 && PCI && AMD_NB 881 ---help--- 882 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 883 GART based hardware IOMMUs. 884 885 The GART supports full DMA access for devices with 32-bit access 886 limitations, on systems with more than 3 GB. This is usually needed 887 for USB, sound, many IDE/SATA chipsets and some other devices. 888 889 Newer systems typically have a modern AMD IOMMU, supported via 890 the CONFIG_AMD_IOMMU=y config option. 891 892 In normal configurations this driver is only active when needed: 893 there's more than 3 GB of memory and the system contains a 894 32-bit limited device. 895 896 If unsure, say Y. 897 898config CALGARY_IOMMU 899 bool "IBM Calgary IOMMU support" 900 select SWIOTLB 901 depends on X86_64 && PCI 902 ---help--- 903 Support for hardware IOMMUs in IBM's xSeries x366 and x460 904 systems. Needed to run systems with more than 3GB of memory 905 properly with 32-bit PCI devices that do not support DAC 906 (Double Address Cycle). Calgary also supports bus level 907 isolation, where all DMAs pass through the IOMMU. This 908 prevents them from going anywhere except their intended 909 destination. This catches hard-to-find kernel bugs and 910 mis-behaving drivers and devices that do not use the DMA-API 911 properly to set up their DMA buffers. The IOMMU can be 912 turned off at boot time with the iommu=off parameter. 913 Normally the kernel will make the right choice by itself. 914 If unsure, say Y. 915 916config CALGARY_IOMMU_ENABLED_BY_DEFAULT 917 def_bool y 918 prompt "Should Calgary be enabled by default?" 919 depends on CALGARY_IOMMU 920 ---help--- 921 Should Calgary be enabled by default? if you choose 'y', Calgary 922 will be used (if it exists). If you choose 'n', Calgary will not be 923 used even if it exists. If you choose 'n' and would like to use 924 Calgary anyway, pass 'iommu=calgary' on the kernel command line. 925 If unsure, say Y. 926 927# need this always selected by IOMMU for the VIA workaround 928config SWIOTLB 929 def_bool y if X86_64 930 ---help--- 931 Support for software bounce buffers used on x86-64 systems 932 which don't have a hardware IOMMU. Using this PCI devices 933 which can only access 32-bits of memory can be used on systems 934 with more than 3 GB of memory. 935 If unsure, say Y. 936 937config IOMMU_HELPER 938 def_bool y 939 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU 940 941config MAXSMP 942 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 943 depends on X86_64 && SMP && DEBUG_KERNEL 944 select CPUMASK_OFFSTACK 945 ---help--- 946 Enable maximum number of CPUS and NUMA Nodes for this architecture. 947 If unsure, say N. 948 949config NR_CPUS 950 int "Maximum number of CPUs" if SMP && !MAXSMP 951 range 2 8 if SMP && X86_32 && !X86_BIGSMP 952 range 2 64 if SMP && X86_32 && X86_BIGSMP 953 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK && X86_64 954 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64 955 default "1" if !SMP 956 default "8192" if MAXSMP 957 default "32" if SMP && X86_BIGSMP 958 default "8" if SMP && X86_32 959 default "64" if SMP 960 ---help--- 961 This allows you to specify the maximum number of CPUs which this 962 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 963 supported value is 8192, otherwise the maximum value is 512. The 964 minimum value which makes sense is 2. 965 966 This is purely to save memory - each supported CPU adds 967 approximately eight kilobytes to the kernel image. 968 969config SCHED_SMT 970 bool "SMT (Hyperthreading) scheduler support" 971 depends on SMP 972 ---help--- 973 SMT scheduler support improves the CPU scheduler's decision making 974 when dealing with Intel Pentium 4 chips with HyperThreading at a 975 cost of slightly increased overhead in some places. If unsure say 976 N here. 977 978config SCHED_MC 979 def_bool y 980 prompt "Multi-core scheduler support" 981 depends on SMP 982 ---help--- 983 Multi-core scheduler support improves the CPU scheduler's decision 984 making when dealing with multi-core CPU chips at a cost of slightly 985 increased overhead in some places. If unsure say N here. 986 987config SCHED_MC_PRIO 988 bool "CPU core priorities scheduler support" 989 depends on SCHED_MC && CPU_SUP_INTEL 990 select X86_INTEL_PSTATE 991 select CPU_FREQ 992 default y 993 ---help--- 994 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 995 core ordering determined at manufacturing time, which allows 996 certain cores to reach higher turbo frequencies (when running 997 single threaded workloads) than others. 998 999 Enabling this kernel feature teaches the scheduler about 1000 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1001 scheduler's CPU selection logic accordingly, so that higher 1002 overall system performance can be achieved. 1003 1004 This feature will have no effect on CPUs without this feature. 1005 1006 If unsure say Y here. 1007 1008source "kernel/Kconfig.preempt" 1009 1010config UP_LATE_INIT 1011 def_bool y 1012 depends on !SMP && X86_LOCAL_APIC 1013 1014config X86_UP_APIC 1015 bool "Local APIC support on uniprocessors" if !PCI_MSI 1016 default PCI_MSI 1017 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1018 ---help--- 1019 A local APIC (Advanced Programmable Interrupt Controller) is an 1020 integrated interrupt controller in the CPU. If you have a single-CPU 1021 system which has a processor with a local APIC, you can say Y here to 1022 enable and use it. If you say Y here even though your machine doesn't 1023 have a local APIC, then the kernel will still run with no slowdown at 1024 all. The local APIC supports CPU-generated self-interrupts (timer, 1025 performance counters), and the NMI watchdog which detects hard 1026 lockups. 1027 1028config X86_UP_IOAPIC 1029 bool "IO-APIC support on uniprocessors" 1030 depends on X86_UP_APIC 1031 ---help--- 1032 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1033 SMP-capable replacement for PC-style interrupt controllers. Most 1034 SMP systems and many recent uniprocessor systems have one. 1035 1036 If you have a single-CPU system with an IO-APIC, you can say Y here 1037 to use it. If you say Y here even though your machine doesn't have 1038 an IO-APIC, then the kernel will still run with no slowdown at all. 1039 1040config X86_LOCAL_APIC 1041 def_bool y 1042 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1043 select IRQ_DOMAIN_HIERARCHY 1044 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1045 1046config X86_IO_APIC 1047 def_bool y 1048 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1049 1050config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1051 bool "Reroute for broken boot IRQs" 1052 depends on X86_IO_APIC 1053 ---help--- 1054 This option enables a workaround that fixes a source of 1055 spurious interrupts. This is recommended when threaded 1056 interrupt handling is used on systems where the generation of 1057 superfluous "boot interrupts" cannot be disabled. 1058 1059 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1060 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1061 kernel does during interrupt handling). On chipsets where this 1062 boot IRQ generation cannot be disabled, this workaround keeps 1063 the original IRQ line masked so that only the equivalent "boot 1064 IRQ" is delivered to the CPUs. The workaround also tells the 1065 kernel to set up the IRQ handler on the boot IRQ line. In this 1066 way only one interrupt is delivered to the kernel. Otherwise 1067 the spurious second interrupt may cause the kernel to bring 1068 down (vital) interrupt lines. 1069 1070 Only affects "broken" chipsets. Interrupt sharing may be 1071 increased on these systems. 1072 1073config X86_MCE 1074 bool "Machine Check / overheating reporting" 1075 select GENERIC_ALLOCATOR 1076 default y 1077 ---help--- 1078 Machine Check support allows the processor to notify the 1079 kernel if it detects a problem (e.g. overheating, data corruption). 1080 The action the kernel takes depends on the severity of the problem, 1081 ranging from warning messages to halting the machine. 1082 1083config X86_MCELOG_LEGACY 1084 bool "Support for deprecated /dev/mcelog character device" 1085 depends on X86_MCE 1086 ---help--- 1087 Enable support for /dev/mcelog which is needed by the old mcelog 1088 userspace logging daemon. Consider switching to the new generation 1089 rasdaemon solution. 1090 1091config X86_MCE_INTEL 1092 def_bool y 1093 prompt "Intel MCE features" 1094 depends on X86_MCE && X86_LOCAL_APIC 1095 ---help--- 1096 Additional support for intel specific MCE features such as 1097 the thermal monitor. 1098 1099config X86_MCE_AMD 1100 def_bool y 1101 prompt "AMD MCE features" 1102 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1103 ---help--- 1104 Additional support for AMD specific MCE features such as 1105 the DRAM Error Threshold. 1106 1107config X86_ANCIENT_MCE 1108 bool "Support for old Pentium 5 / WinChip machine checks" 1109 depends on X86_32 && X86_MCE 1110 ---help--- 1111 Include support for machine check handling on old Pentium 5 or WinChip 1112 systems. These typically need to be enabled explicitly on the command 1113 line. 1114 1115config X86_MCE_THRESHOLD 1116 depends on X86_MCE_AMD || X86_MCE_INTEL 1117 def_bool y 1118 1119config X86_MCE_INJECT 1120 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1121 tristate "Machine check injector support" 1122 ---help--- 1123 Provide support for injecting machine checks for testing purposes. 1124 If you don't know what a machine check is and you don't do kernel 1125 QA it is safe to say n. 1126 1127config X86_THERMAL_VECTOR 1128 def_bool y 1129 depends on X86_MCE_INTEL 1130 1131source "arch/x86/events/Kconfig" 1132 1133config X86_LEGACY_VM86 1134 bool "Legacy VM86 support" 1135 default n 1136 depends on X86_32 1137 ---help--- 1138 This option allows user programs to put the CPU into V8086 1139 mode, which is an 80286-era approximation of 16-bit real mode. 1140 1141 Some very old versions of X and/or vbetool require this option 1142 for user mode setting. Similarly, DOSEMU will use it if 1143 available to accelerate real mode DOS programs. However, any 1144 recent version of DOSEMU, X, or vbetool should be fully 1145 functional even without kernel VM86 support, as they will all 1146 fall back to software emulation. Nevertheless, if you are using 1147 a 16-bit DOS program where 16-bit performance matters, vm86 1148 mode might be faster than emulation and you might want to 1149 enable this option. 1150 1151 Note that any app that works on a 64-bit kernel is unlikely to 1152 need this option, as 64-bit kernels don't, and can't, support 1153 V8086 mode. This option is also unrelated to 16-bit protected 1154 mode and is not needed to run most 16-bit programs under Wine. 1155 1156 Enabling this option increases the complexity of the kernel 1157 and slows down exception handling a tiny bit. 1158 1159 If unsure, say N here. 1160 1161config VM86 1162 bool 1163 default X86_LEGACY_VM86 1164 1165config X86_16BIT 1166 bool "Enable support for 16-bit segments" if EXPERT 1167 default y 1168 depends on MODIFY_LDT_SYSCALL 1169 ---help--- 1170 This option is required by programs like Wine to run 16-bit 1171 protected mode legacy code on x86 processors. Disabling 1172 this option saves about 300 bytes on i386, or around 6K text 1173 plus 16K runtime memory on x86-64, 1174 1175config X86_ESPFIX32 1176 def_bool y 1177 depends on X86_16BIT && X86_32 1178 1179config X86_ESPFIX64 1180 def_bool y 1181 depends on X86_16BIT && X86_64 1182 1183config X86_VSYSCALL_EMULATION 1184 bool "Enable vsyscall emulation" if EXPERT 1185 default y 1186 depends on X86_64 1187 ---help--- 1188 This enables emulation of the legacy vsyscall page. Disabling 1189 it is roughly equivalent to booting with vsyscall=none, except 1190 that it will also disable the helpful warning if a program 1191 tries to use a vsyscall. With this option set to N, offending 1192 programs will just segfault, citing addresses of the form 1193 0xffffffffff600?00. 1194 1195 This option is required by many programs built before 2013, and 1196 care should be used even with newer programs if set to N. 1197 1198 Disabling this option saves about 7K of kernel size and 1199 possibly 4K of additional runtime pagetable memory. 1200 1201config TOSHIBA 1202 tristate "Toshiba Laptop support" 1203 depends on X86_32 1204 ---help--- 1205 This adds a driver to safely access the System Management Mode of 1206 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1207 not work on models with a Phoenix BIOS. The System Management Mode 1208 is used to set the BIOS and power saving options on Toshiba portables. 1209 1210 For information on utilities to make use of this driver see the 1211 Toshiba Linux utilities web site at: 1212 <http://www.buzzard.org.uk/toshiba/>. 1213 1214 Say Y if you intend to run this kernel on a Toshiba portable. 1215 Say N otherwise. 1216 1217config I8K 1218 tristate "Dell i8k legacy laptop support" 1219 select HWMON 1220 select SENSORS_DELL_SMM 1221 ---help--- 1222 This option enables legacy /proc/i8k userspace interface in hwmon 1223 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1224 temperature and allows controlling fan speeds of Dell laptops via 1225 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1226 it reports also power and hotkey status. For fan speed control is 1227 needed userspace package i8kutils. 1228 1229 Say Y if you intend to run this kernel on old Dell laptops or want to 1230 use userspace package i8kutils. 1231 Say N otherwise. 1232 1233config X86_REBOOTFIXUPS 1234 bool "Enable X86 board specific fixups for reboot" 1235 depends on X86_32 1236 ---help--- 1237 This enables chipset and/or board specific fixups to be done 1238 in order to get reboot to work correctly. This is only needed on 1239 some combinations of hardware and BIOS. The symptom, for which 1240 this config is intended, is when reboot ends with a stalled/hung 1241 system. 1242 1243 Currently, the only fixup is for the Geode machines using 1244 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1245 1246 Say Y if you want to enable the fixup. Currently, it's safe to 1247 enable this option even if you don't need it. 1248 Say N otherwise. 1249 1250config MICROCODE 1251 bool "CPU microcode loading support" 1252 default y 1253 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1254 select FW_LOADER 1255 ---help--- 1256 If you say Y here, you will be able to update the microcode on 1257 Intel and AMD processors. The Intel support is for the IA32 family, 1258 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1259 AMD support is for families 0x10 and later. You will obviously need 1260 the actual microcode binary data itself which is not shipped with 1261 the Linux kernel. 1262 1263 The preferred method to load microcode from a detached initrd is described 1264 in Documentation/x86/early-microcode.txt. For that you need to enable 1265 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1266 initrd for microcode blobs. 1267 1268 In addition, you can build the microcode into the kernel. For that you 1269 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1270 config option. 1271 1272config MICROCODE_INTEL 1273 bool "Intel microcode loading support" 1274 depends on MICROCODE 1275 default MICROCODE 1276 select FW_LOADER 1277 ---help--- 1278 This options enables microcode patch loading support for Intel 1279 processors. 1280 1281 For the current Intel microcode data package go to 1282 <https://downloadcenter.intel.com> and search for 1283 'Linux Processor Microcode Data File'. 1284 1285config MICROCODE_AMD 1286 bool "AMD microcode loading support" 1287 depends on MICROCODE 1288 select FW_LOADER 1289 ---help--- 1290 If you select this option, microcode patch loading support for AMD 1291 processors will be enabled. 1292 1293config MICROCODE_OLD_INTERFACE 1294 def_bool y 1295 depends on MICROCODE 1296 1297config X86_MSR 1298 tristate "/dev/cpu/*/msr - Model-specific register support" 1299 ---help--- 1300 This device gives privileged processes access to the x86 1301 Model-Specific Registers (MSRs). It is a character device with 1302 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1303 MSR accesses are directed to a specific CPU on multi-processor 1304 systems. 1305 1306config X86_CPUID 1307 tristate "/dev/cpu/*/cpuid - CPU information support" 1308 ---help--- 1309 This device gives processes access to the x86 CPUID instruction to 1310 be executed on a specific processor. It is a character device 1311 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1312 /dev/cpu/31/cpuid. 1313 1314choice 1315 prompt "High Memory Support" 1316 default HIGHMEM4G 1317 depends on X86_32 1318 1319config NOHIGHMEM 1320 bool "off" 1321 ---help--- 1322 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1323 However, the address space of 32-bit x86 processors is only 4 1324 Gigabytes large. That means that, if you have a large amount of 1325 physical memory, not all of it can be "permanently mapped" by the 1326 kernel. The physical memory that's not permanently mapped is called 1327 "high memory". 1328 1329 If you are compiling a kernel which will never run on a machine with 1330 more than 1 Gigabyte total physical RAM, answer "off" here (default 1331 choice and suitable for most users). This will result in a "3GB/1GB" 1332 split: 3GB are mapped so that each process sees a 3GB virtual memory 1333 space and the remaining part of the 4GB virtual memory space is used 1334 by the kernel to permanently map as much physical memory as 1335 possible. 1336 1337 If the machine has between 1 and 4 Gigabytes physical RAM, then 1338 answer "4GB" here. 1339 1340 If more than 4 Gigabytes is used then answer "64GB" here. This 1341 selection turns Intel PAE (Physical Address Extension) mode on. 1342 PAE implements 3-level paging on IA32 processors. PAE is fully 1343 supported by Linux, PAE mode is implemented on all recent Intel 1344 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1345 then the kernel will not boot on CPUs that don't support PAE! 1346 1347 The actual amount of total physical memory will either be 1348 auto detected or can be forced by using a kernel command line option 1349 such as "mem=256M". (Try "man bootparam" or see the documentation of 1350 your boot loader (lilo or loadlin) about how to pass options to the 1351 kernel at boot time.) 1352 1353 If unsure, say "off". 1354 1355config HIGHMEM4G 1356 bool "4GB" 1357 ---help--- 1358 Select this if you have a 32-bit processor and between 1 and 4 1359 gigabytes of physical RAM. 1360 1361config HIGHMEM64G 1362 bool "64GB" 1363 depends on !M486 1364 select X86_PAE 1365 ---help--- 1366 Select this if you have a 32-bit processor and more than 4 1367 gigabytes of physical RAM. 1368 1369endchoice 1370 1371choice 1372 prompt "Memory split" if EXPERT 1373 default VMSPLIT_3G 1374 depends on X86_32 1375 ---help--- 1376 Select the desired split between kernel and user memory. 1377 1378 If the address range available to the kernel is less than the 1379 physical memory installed, the remaining memory will be available 1380 as "high memory". Accessing high memory is a little more costly 1381 than low memory, as it needs to be mapped into the kernel first. 1382 Note that increasing the kernel address space limits the range 1383 available to user programs, making the address space there 1384 tighter. Selecting anything other than the default 3G/1G split 1385 will also likely make your kernel incompatible with binary-only 1386 kernel modules. 1387 1388 If you are not absolutely sure what you are doing, leave this 1389 option alone! 1390 1391 config VMSPLIT_3G 1392 bool "3G/1G user/kernel split" 1393 config VMSPLIT_3G_OPT 1394 depends on !X86_PAE 1395 bool "3G/1G user/kernel split (for full 1G low memory)" 1396 config VMSPLIT_2G 1397 bool "2G/2G user/kernel split" 1398 config VMSPLIT_2G_OPT 1399 depends on !X86_PAE 1400 bool "2G/2G user/kernel split (for full 2G low memory)" 1401 config VMSPLIT_1G 1402 bool "1G/3G user/kernel split" 1403endchoice 1404 1405config PAGE_OFFSET 1406 hex 1407 default 0xB0000000 if VMSPLIT_3G_OPT 1408 default 0x80000000 if VMSPLIT_2G 1409 default 0x78000000 if VMSPLIT_2G_OPT 1410 default 0x40000000 if VMSPLIT_1G 1411 default 0xC0000000 1412 depends on X86_32 1413 1414config HIGHMEM 1415 def_bool y 1416 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1417 1418config X86_PAE 1419 bool "PAE (Physical Address Extension) Support" 1420 depends on X86_32 && !HIGHMEM4G 1421 select SWIOTLB 1422 ---help--- 1423 PAE is required for NX support, and furthermore enables 1424 larger swapspace support for non-overcommit purposes. It 1425 has the cost of more pagetable lookup overhead, and also 1426 consumes more pagetable space per process. 1427 1428config X86_5LEVEL 1429 bool "Enable 5-level page tables support" 1430 depends on X86_64 1431 ---help--- 1432 5-level paging enables access to larger address space: 1433 upto 128 PiB of virtual address space and 4 PiB of 1434 physical address space. 1435 1436 It will be supported by future Intel CPUs. 1437 1438 Note: a kernel with this option enabled can only be booted 1439 on machines that support the feature. 1440 1441 See Documentation/x86/x86_64/5level-paging.txt for more 1442 information. 1443 1444 Say N if unsure. 1445 1446config ARCH_PHYS_ADDR_T_64BIT 1447 def_bool y 1448 depends on X86_64 || X86_PAE 1449 1450config ARCH_DMA_ADDR_T_64BIT 1451 def_bool y 1452 depends on X86_64 || HIGHMEM64G 1453 1454config X86_DIRECT_GBPAGES 1455 def_bool y 1456 depends on X86_64 && !DEBUG_PAGEALLOC 1457 ---help--- 1458 Certain kernel features effectively disable kernel 1459 linear 1 GB mappings (even if the CPU otherwise 1460 supports them), so don't confuse the user by printing 1461 that we have them enabled. 1462 1463config ARCH_HAS_MEM_ENCRYPT 1464 def_bool y 1465 1466config AMD_MEM_ENCRYPT 1467 bool "AMD Secure Memory Encryption (SME) support" 1468 depends on X86_64 && CPU_SUP_AMD 1469 ---help--- 1470 Say yes to enable support for the encryption of system memory. 1471 This requires an AMD processor that supports Secure Memory 1472 Encryption (SME). 1473 1474config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1475 bool "Activate AMD Secure Memory Encryption (SME) by default" 1476 default y 1477 depends on AMD_MEM_ENCRYPT 1478 ---help--- 1479 Say yes to have system memory encrypted by default if running on 1480 an AMD processor that supports Secure Memory Encryption (SME). 1481 1482 If set to Y, then the encryption of system memory can be 1483 deactivated with the mem_encrypt=off command line option. 1484 1485 If set to N, then the encryption of system memory can be 1486 activated with the mem_encrypt=on command line option. 1487 1488config ARCH_USE_MEMREMAP_PROT 1489 def_bool y 1490 depends on AMD_MEM_ENCRYPT 1491 1492# Common NUMA Features 1493config NUMA 1494 bool "Numa Memory Allocation and Scheduler Support" 1495 depends on SMP 1496 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1497 default y if X86_BIGSMP 1498 ---help--- 1499 Enable NUMA (Non Uniform Memory Access) support. 1500 1501 The kernel will try to allocate memory used by a CPU on the 1502 local memory controller of the CPU and add some more 1503 NUMA awareness to the kernel. 1504 1505 For 64-bit this is recommended if the system is Intel Core i7 1506 (or later), AMD Opteron, or EM64T NUMA. 1507 1508 For 32-bit this is only needed if you boot a 32-bit 1509 kernel on a 64-bit NUMA platform. 1510 1511 Otherwise, you should say N. 1512 1513config AMD_NUMA 1514 def_bool y 1515 prompt "Old style AMD Opteron NUMA detection" 1516 depends on X86_64 && NUMA && PCI 1517 ---help--- 1518 Enable AMD NUMA node topology detection. You should say Y here if 1519 you have a multi processor AMD system. This uses an old method to 1520 read the NUMA configuration directly from the builtin Northbridge 1521 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1522 which also takes priority if both are compiled in. 1523 1524config X86_64_ACPI_NUMA 1525 def_bool y 1526 prompt "ACPI NUMA detection" 1527 depends on X86_64 && NUMA && ACPI && PCI 1528 select ACPI_NUMA 1529 ---help--- 1530 Enable ACPI SRAT based node topology detection. 1531 1532# Some NUMA nodes have memory ranges that span 1533# other nodes. Even though a pfn is valid and 1534# between a node's start and end pfns, it may not 1535# reside on that node. See memmap_init_zone() 1536# for details. 1537config NODES_SPAN_OTHER_NODES 1538 def_bool y 1539 depends on X86_64_ACPI_NUMA 1540 1541config NUMA_EMU 1542 bool "NUMA emulation" 1543 depends on NUMA 1544 ---help--- 1545 Enable NUMA emulation. A flat machine will be split 1546 into virtual nodes when booted with "numa=fake=N", where N is the 1547 number of nodes. This is only useful for debugging. 1548 1549config NODES_SHIFT 1550 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1551 range 1 10 1552 default "10" if MAXSMP 1553 default "6" if X86_64 1554 default "3" 1555 depends on NEED_MULTIPLE_NODES 1556 ---help--- 1557 Specify the maximum number of NUMA Nodes available on the target 1558 system. Increases memory reserved to accommodate various tables. 1559 1560config ARCH_HAVE_MEMORY_PRESENT 1561 def_bool y 1562 depends on X86_32 && DISCONTIGMEM 1563 1564config NEED_NODE_MEMMAP_SIZE 1565 def_bool y 1566 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM) 1567 1568config ARCH_FLATMEM_ENABLE 1569 def_bool y 1570 depends on X86_32 && !NUMA 1571 1572config ARCH_DISCONTIGMEM_ENABLE 1573 def_bool y 1574 depends on NUMA && X86_32 1575 1576config ARCH_DISCONTIGMEM_DEFAULT 1577 def_bool y 1578 depends on NUMA && X86_32 1579 1580config ARCH_SPARSEMEM_ENABLE 1581 def_bool y 1582 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1583 select SPARSEMEM_STATIC if X86_32 1584 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1585 1586config ARCH_SPARSEMEM_DEFAULT 1587 def_bool y 1588 depends on X86_64 1589 1590config ARCH_SELECT_MEMORY_MODEL 1591 def_bool y 1592 depends on ARCH_SPARSEMEM_ENABLE 1593 1594config ARCH_MEMORY_PROBE 1595 bool "Enable sysfs memory/probe interface" 1596 depends on X86_64 && MEMORY_HOTPLUG 1597 help 1598 This option enables a sysfs memory/probe interface for testing. 1599 See Documentation/memory-hotplug.txt for more information. 1600 If you are unsure how to answer this question, answer N. 1601 1602config ARCH_PROC_KCORE_TEXT 1603 def_bool y 1604 depends on X86_64 && PROC_KCORE 1605 1606config ILLEGAL_POINTER_VALUE 1607 hex 1608 default 0 if X86_32 1609 default 0xdead000000000000 if X86_64 1610 1611source "mm/Kconfig" 1612 1613config X86_PMEM_LEGACY_DEVICE 1614 bool 1615 1616config X86_PMEM_LEGACY 1617 tristate "Support non-standard NVDIMMs and ADR protected memory" 1618 depends on PHYS_ADDR_T_64BIT 1619 depends on BLK_DEV 1620 select X86_PMEM_LEGACY_DEVICE 1621 select LIBNVDIMM 1622 help 1623 Treat memory marked using the non-standard e820 type of 12 as used 1624 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1625 The kernel will offer these regions to the 'pmem' driver so 1626 they can be used for persistent storage. 1627 1628 Say Y if unsure. 1629 1630config HIGHPTE 1631 bool "Allocate 3rd-level pagetables from highmem" 1632 depends on HIGHMEM 1633 ---help--- 1634 The VM uses one page table entry for each page of physical memory. 1635 For systems with a lot of RAM, this can be wasteful of precious 1636 low memory. Setting this option will put user-space page table 1637 entries in high memory. 1638 1639config X86_CHECK_BIOS_CORRUPTION 1640 bool "Check for low memory corruption" 1641 ---help--- 1642 Periodically check for memory corruption in low memory, which 1643 is suspected to be caused by BIOS. Even when enabled in the 1644 configuration, it is disabled at runtime. Enable it by 1645 setting "memory_corruption_check=1" on the kernel command 1646 line. By default it scans the low 64k of memory every 60 1647 seconds; see the memory_corruption_check_size and 1648 memory_corruption_check_period parameters in 1649 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1650 1651 When enabled with the default parameters, this option has 1652 almost no overhead, as it reserves a relatively small amount 1653 of memory and scans it infrequently. It both detects corruption 1654 and prevents it from affecting the running system. 1655 1656 It is, however, intended as a diagnostic tool; if repeatable 1657 BIOS-originated corruption always affects the same memory, 1658 you can use memmap= to prevent the kernel from using that 1659 memory. 1660 1661config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1662 bool "Set the default setting of memory_corruption_check" 1663 depends on X86_CHECK_BIOS_CORRUPTION 1664 default y 1665 ---help--- 1666 Set whether the default state of memory_corruption_check is 1667 on or off. 1668 1669config X86_RESERVE_LOW 1670 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1671 default 64 1672 range 4 640 1673 ---help--- 1674 Specify the amount of low memory to reserve for the BIOS. 1675 1676 The first page contains BIOS data structures that the kernel 1677 must not use, so that page must always be reserved. 1678 1679 By default we reserve the first 64K of physical RAM, as a 1680 number of BIOSes are known to corrupt that memory range 1681 during events such as suspend/resume or monitor cable 1682 insertion, so it must not be used by the kernel. 1683 1684 You can set this to 4 if you are absolutely sure that you 1685 trust the BIOS to get all its memory reservations and usages 1686 right. If you know your BIOS have problems beyond the 1687 default 64K area, you can set this to 640 to avoid using the 1688 entire low memory range. 1689 1690 If you have doubts about the BIOS (e.g. suspend/resume does 1691 not work or there's kernel crashes after certain hardware 1692 hotplug events) then you might want to enable 1693 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1694 typical corruption patterns. 1695 1696 Leave this to the default value of 64 if you are unsure. 1697 1698config MATH_EMULATION 1699 bool 1700 depends on MODIFY_LDT_SYSCALL 1701 prompt "Math emulation" if X86_32 1702 ---help--- 1703 Linux can emulate a math coprocessor (used for floating point 1704 operations) if you don't have one. 486DX and Pentium processors have 1705 a math coprocessor built in, 486SX and 386 do not, unless you added 1706 a 487DX or 387, respectively. (The messages during boot time can 1707 give you some hints here ["man dmesg"].) Everyone needs either a 1708 coprocessor or this emulation. 1709 1710 If you don't have a math coprocessor, you need to say Y here; if you 1711 say Y here even though you have a coprocessor, the coprocessor will 1712 be used nevertheless. (This behavior can be changed with the kernel 1713 command line option "no387", which comes handy if your coprocessor 1714 is broken. Try "man bootparam" or see the documentation of your boot 1715 loader (lilo or loadlin) about how to pass options to the kernel at 1716 boot time.) This means that it is a good idea to say Y here if you 1717 intend to use this kernel on different machines. 1718 1719 More information about the internals of the Linux math coprocessor 1720 emulation can be found in <file:arch/x86/math-emu/README>. 1721 1722 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1723 kernel, it won't hurt. 1724 1725config MTRR 1726 def_bool y 1727 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1728 ---help--- 1729 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1730 the Memory Type Range Registers (MTRRs) may be used to control 1731 processor access to memory ranges. This is most useful if you have 1732 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1733 allows bus write transfers to be combined into a larger transfer 1734 before bursting over the PCI/AGP bus. This can increase performance 1735 of image write operations 2.5 times or more. Saying Y here creates a 1736 /proc/mtrr file which may be used to manipulate your processor's 1737 MTRRs. Typically the X server should use this. 1738 1739 This code has a reasonably generic interface so that similar 1740 control registers on other processors can be easily supported 1741 as well: 1742 1743 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1744 Registers (ARRs) which provide a similar functionality to MTRRs. For 1745 these, the ARRs are used to emulate the MTRRs. 1746 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1747 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1748 write-combining. All of these processors are supported by this code 1749 and it makes sense to say Y here if you have one of them. 1750 1751 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1752 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1753 can lead to all sorts of problems, so it's good to say Y here. 1754 1755 You can safely say Y even if your machine doesn't have MTRRs, you'll 1756 just add about 9 KB to your kernel. 1757 1758 See <file:Documentation/x86/mtrr.txt> for more information. 1759 1760config MTRR_SANITIZER 1761 def_bool y 1762 prompt "MTRR cleanup support" 1763 depends on MTRR 1764 ---help--- 1765 Convert MTRR layout from continuous to discrete, so X drivers can 1766 add writeback entries. 1767 1768 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1769 The largest mtrr entry size for a continuous block can be set with 1770 mtrr_chunk_size. 1771 1772 If unsure, say Y. 1773 1774config MTRR_SANITIZER_ENABLE_DEFAULT 1775 int "MTRR cleanup enable value (0-1)" 1776 range 0 1 1777 default "0" 1778 depends on MTRR_SANITIZER 1779 ---help--- 1780 Enable mtrr cleanup default value 1781 1782config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1783 int "MTRR cleanup spare reg num (0-7)" 1784 range 0 7 1785 default "1" 1786 depends on MTRR_SANITIZER 1787 ---help--- 1788 mtrr cleanup spare entries default, it can be changed via 1789 mtrr_spare_reg_nr=N on the kernel command line. 1790 1791config X86_PAT 1792 def_bool y 1793 prompt "x86 PAT support" if EXPERT 1794 depends on MTRR 1795 ---help--- 1796 Use PAT attributes to setup page level cache control. 1797 1798 PATs are the modern equivalents of MTRRs and are much more 1799 flexible than MTRRs. 1800 1801 Say N here if you see bootup problems (boot crash, boot hang, 1802 spontaneous reboots) or a non-working video driver. 1803 1804 If unsure, say Y. 1805 1806config ARCH_USES_PG_UNCACHED 1807 def_bool y 1808 depends on X86_PAT 1809 1810config ARCH_RANDOM 1811 def_bool y 1812 prompt "x86 architectural random number generator" if EXPERT 1813 ---help--- 1814 Enable the x86 architectural RDRAND instruction 1815 (Intel Bull Mountain technology) to generate random numbers. 1816 If supported, this is a high bandwidth, cryptographically 1817 secure hardware random number generator. 1818 1819config X86_SMAP 1820 def_bool y 1821 prompt "Supervisor Mode Access Prevention" if EXPERT 1822 ---help--- 1823 Supervisor Mode Access Prevention (SMAP) is a security 1824 feature in newer Intel processors. There is a small 1825 performance cost if this enabled and turned on; there is 1826 also a small increase in the kernel size if this is enabled. 1827 1828 If unsure, say Y. 1829 1830config X86_INTEL_UMIP 1831 def_bool y 1832 depends on CPU_SUP_INTEL 1833 prompt "Intel User Mode Instruction Prevention" if EXPERT 1834 ---help--- 1835 The User Mode Instruction Prevention (UMIP) is a security 1836 feature in newer Intel processors. If enabled, a general 1837 protection fault is issued if the SGDT, SLDT, SIDT, SMSW 1838 or STR instructions are executed in user mode. These instructions 1839 unnecessarily expose information about the hardware state. 1840 1841 The vast majority of applications do not use these instructions. 1842 For the very few that do, software emulation is provided in 1843 specific cases in protected and virtual-8086 modes. Emulated 1844 results are dummy. 1845 1846config X86_INTEL_MPX 1847 prompt "Intel MPX (Memory Protection Extensions)" 1848 def_bool n 1849 # Note: only available in 64-bit mode due to VMA flags shortage 1850 depends on CPU_SUP_INTEL && X86_64 1851 select ARCH_USES_HIGH_VMA_FLAGS 1852 ---help--- 1853 MPX provides hardware features that can be used in 1854 conjunction with compiler-instrumented code to check 1855 memory references. It is designed to detect buffer 1856 overflow or underflow bugs. 1857 1858 This option enables running applications which are 1859 instrumented or otherwise use MPX. It does not use MPX 1860 itself inside the kernel or to protect the kernel 1861 against bad memory references. 1862 1863 Enabling this option will make the kernel larger: 1864 ~8k of kernel text and 36 bytes of data on a 64-bit 1865 defconfig. It adds a long to the 'mm_struct' which 1866 will increase the kernel memory overhead of each 1867 process and adds some branches to paths used during 1868 exec() and munmap(). 1869 1870 For details, see Documentation/x86/intel_mpx.txt 1871 1872 If unsure, say N. 1873 1874config X86_INTEL_MEMORY_PROTECTION_KEYS 1875 prompt "Intel Memory Protection Keys" 1876 def_bool y 1877 # Note: only available in 64-bit mode 1878 depends on CPU_SUP_INTEL && X86_64 1879 select ARCH_USES_HIGH_VMA_FLAGS 1880 select ARCH_HAS_PKEYS 1881 ---help--- 1882 Memory Protection Keys provides a mechanism for enforcing 1883 page-based protections, but without requiring modification of the 1884 page tables when an application changes protection domains. 1885 1886 For details, see Documentation/x86/protection-keys.txt 1887 1888 If unsure, say y. 1889 1890config EFI 1891 bool "EFI runtime service support" 1892 depends on ACPI 1893 select UCS2_STRING 1894 select EFI_RUNTIME_WRAPPERS 1895 ---help--- 1896 This enables the kernel to use EFI runtime services that are 1897 available (such as the EFI variable services). 1898 1899 This option is only useful on systems that have EFI firmware. 1900 In addition, you should use the latest ELILO loader available 1901 at <http://elilo.sourceforge.net> in order to take advantage 1902 of EFI runtime services. However, even with this option, the 1903 resultant kernel should continue to boot on existing non-EFI 1904 platforms. 1905 1906config EFI_STUB 1907 bool "EFI stub support" 1908 depends on EFI && !X86_USE_3DNOW 1909 select RELOCATABLE 1910 ---help--- 1911 This kernel feature allows a bzImage to be loaded directly 1912 by EFI firmware without the use of a bootloader. 1913 1914 See Documentation/efi-stub.txt for more information. 1915 1916config EFI_MIXED 1917 bool "EFI mixed-mode support" 1918 depends on EFI_STUB && X86_64 1919 ---help--- 1920 Enabling this feature allows a 64-bit kernel to be booted 1921 on a 32-bit firmware, provided that your CPU supports 64-bit 1922 mode. 1923 1924 Note that it is not possible to boot a mixed-mode enabled 1925 kernel via the EFI boot stub - a bootloader that supports 1926 the EFI handover protocol must be used. 1927 1928 If unsure, say N. 1929 1930config SECCOMP 1931 def_bool y 1932 prompt "Enable seccomp to safely compute untrusted bytecode" 1933 ---help--- 1934 This kernel feature is useful for number crunching applications 1935 that may need to compute untrusted bytecode during their 1936 execution. By using pipes or other transports made available to 1937 the process as file descriptors supporting the read/write 1938 syscalls, it's possible to isolate those applications in 1939 their own address space using seccomp. Once seccomp is 1940 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 1941 and the task is only allowed to execute a few safe syscalls 1942 defined by each seccomp mode. 1943 1944 If unsure, say Y. Only embedded should say N here. 1945 1946source kernel/Kconfig.hz 1947 1948config KEXEC 1949 bool "kexec system call" 1950 select KEXEC_CORE 1951 ---help--- 1952 kexec is a system call that implements the ability to shutdown your 1953 current kernel, and to start another kernel. It is like a reboot 1954 but it is independent of the system firmware. And like a reboot 1955 you can start any kernel with it, not just Linux. 1956 1957 The name comes from the similarity to the exec system call. 1958 1959 It is an ongoing process to be certain the hardware in a machine 1960 is properly shutdown, so do not be surprised if this code does not 1961 initially work for you. As of this writing the exact hardware 1962 interface is strongly in flux, so no good recommendation can be 1963 made. 1964 1965config KEXEC_FILE 1966 bool "kexec file based system call" 1967 select KEXEC_CORE 1968 select BUILD_BIN2C 1969 depends on X86_64 1970 depends on CRYPTO=y 1971 depends on CRYPTO_SHA256=y 1972 ---help--- 1973 This is new version of kexec system call. This system call is 1974 file based and takes file descriptors as system call argument 1975 for kernel and initramfs as opposed to list of segments as 1976 accepted by previous system call. 1977 1978config KEXEC_VERIFY_SIG 1979 bool "Verify kernel signature during kexec_file_load() syscall" 1980 depends on KEXEC_FILE 1981 ---help--- 1982 This option makes kernel signature verification mandatory for 1983 the kexec_file_load() syscall. 1984 1985 In addition to that option, you need to enable signature 1986 verification for the corresponding kernel image type being 1987 loaded in order for this to work. 1988 1989config KEXEC_BZIMAGE_VERIFY_SIG 1990 bool "Enable bzImage signature verification support" 1991 depends on KEXEC_VERIFY_SIG 1992 depends on SIGNED_PE_FILE_VERIFICATION 1993 select SYSTEM_TRUSTED_KEYRING 1994 ---help--- 1995 Enable bzImage signature verification support. 1996 1997config CRASH_DUMP 1998 bool "kernel crash dumps" 1999 depends on X86_64 || (X86_32 && HIGHMEM) 2000 ---help--- 2001 Generate crash dump after being started by kexec. 2002 This should be normally only set in special crash dump kernels 2003 which are loaded in the main kernel with kexec-tools into 2004 a specially reserved region and then later executed after 2005 a crash by kdump/kexec. The crash dump kernel must be compiled 2006 to a memory address not used by the main kernel or BIOS using 2007 PHYSICAL_START, or it must be built as a relocatable image 2008 (CONFIG_RELOCATABLE=y). 2009 For more details see Documentation/kdump/kdump.txt 2010 2011config KEXEC_JUMP 2012 bool "kexec jump" 2013 depends on KEXEC && HIBERNATION 2014 ---help--- 2015 Jump between original kernel and kexeced kernel and invoke 2016 code in physical address mode via KEXEC 2017 2018config PHYSICAL_START 2019 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2020 default "0x1000000" 2021 ---help--- 2022 This gives the physical address where the kernel is loaded. 2023 2024 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2025 bzImage will decompress itself to above physical address and 2026 run from there. Otherwise, bzImage will run from the address where 2027 it has been loaded by the boot loader and will ignore above physical 2028 address. 2029 2030 In normal kdump cases one does not have to set/change this option 2031 as now bzImage can be compiled as a completely relocatable image 2032 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2033 address. This option is mainly useful for the folks who don't want 2034 to use a bzImage for capturing the crash dump and want to use a 2035 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2036 to be specifically compiled to run from a specific memory area 2037 (normally a reserved region) and this option comes handy. 2038 2039 So if you are using bzImage for capturing the crash dump, 2040 leave the value here unchanged to 0x1000000 and set 2041 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2042 for capturing the crash dump change this value to start of 2043 the reserved region. In other words, it can be set based on 2044 the "X" value as specified in the "crashkernel=YM@XM" 2045 command line boot parameter passed to the panic-ed 2046 kernel. Please take a look at Documentation/kdump/kdump.txt 2047 for more details about crash dumps. 2048 2049 Usage of bzImage for capturing the crash dump is recommended as 2050 one does not have to build two kernels. Same kernel can be used 2051 as production kernel and capture kernel. Above option should have 2052 gone away after relocatable bzImage support is introduced. But it 2053 is present because there are users out there who continue to use 2054 vmlinux for dump capture. This option should go away down the 2055 line. 2056 2057 Don't change this unless you know what you are doing. 2058 2059config RELOCATABLE 2060 bool "Build a relocatable kernel" 2061 default y 2062 ---help--- 2063 This builds a kernel image that retains relocation information 2064 so it can be loaded someplace besides the default 1MB. 2065 The relocations tend to make the kernel binary about 10% larger, 2066 but are discarded at runtime. 2067 2068 One use is for the kexec on panic case where the recovery kernel 2069 must live at a different physical address than the primary 2070 kernel. 2071 2072 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2073 it has been loaded at and the compile time physical address 2074 (CONFIG_PHYSICAL_START) is used as the minimum location. 2075 2076config RANDOMIZE_BASE 2077 bool "Randomize the address of the kernel image (KASLR)" 2078 depends on RELOCATABLE 2079 default y 2080 ---help--- 2081 In support of Kernel Address Space Layout Randomization (KASLR), 2082 this randomizes the physical address at which the kernel image 2083 is decompressed and the virtual address where the kernel 2084 image is mapped, as a security feature that deters exploit 2085 attempts relying on knowledge of the location of kernel 2086 code internals. 2087 2088 On 64-bit, the kernel physical and virtual addresses are 2089 randomized separately. The physical address will be anywhere 2090 between 16MB and the top of physical memory (up to 64TB). The 2091 virtual address will be randomized from 16MB up to 1GB (9 bits 2092 of entropy). Note that this also reduces the memory space 2093 available to kernel modules from 1.5GB to 1GB. 2094 2095 On 32-bit, the kernel physical and virtual addresses are 2096 randomized together. They will be randomized from 16MB up to 2097 512MB (8 bits of entropy). 2098 2099 Entropy is generated using the RDRAND instruction if it is 2100 supported. If RDTSC is supported, its value is mixed into 2101 the entropy pool as well. If neither RDRAND nor RDTSC are 2102 supported, then entropy is read from the i8254 timer. The 2103 usable entropy is limited by the kernel being built using 2104 2GB addressing, and that PHYSICAL_ALIGN must be at a 2105 minimum of 2MB. As a result, only 10 bits of entropy are 2106 theoretically possible, but the implementations are further 2107 limited due to memory layouts. 2108 2109 If unsure, say Y. 2110 2111# Relocation on x86 needs some additional build support 2112config X86_NEED_RELOCS 2113 def_bool y 2114 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2115 2116config PHYSICAL_ALIGN 2117 hex "Alignment value to which kernel should be aligned" 2118 default "0x200000" 2119 range 0x2000 0x1000000 if X86_32 2120 range 0x200000 0x1000000 if X86_64 2121 ---help--- 2122 This value puts the alignment restrictions on physical address 2123 where kernel is loaded and run from. Kernel is compiled for an 2124 address which meets above alignment restriction. 2125 2126 If bootloader loads the kernel at a non-aligned address and 2127 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2128 address aligned to above value and run from there. 2129 2130 If bootloader loads the kernel at a non-aligned address and 2131 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2132 load address and decompress itself to the address it has been 2133 compiled for and run from there. The address for which kernel is 2134 compiled already meets above alignment restrictions. Hence the 2135 end result is that kernel runs from a physical address meeting 2136 above alignment restrictions. 2137 2138 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2139 this value must be a multiple of 0x200000. 2140 2141 Don't change this unless you know what you are doing. 2142 2143config RANDOMIZE_MEMORY 2144 bool "Randomize the kernel memory sections" 2145 depends on X86_64 2146 depends on RANDOMIZE_BASE 2147 default RANDOMIZE_BASE 2148 ---help--- 2149 Randomizes the base virtual address of kernel memory sections 2150 (physical memory mapping, vmalloc & vmemmap). This security feature 2151 makes exploits relying on predictable memory locations less reliable. 2152 2153 The order of allocations remains unchanged. Entropy is generated in 2154 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2155 configuration have in average 30,000 different possible virtual 2156 addresses for each memory section. 2157 2158 If unsure, say Y. 2159 2160config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2161 hex "Physical memory mapping padding" if EXPERT 2162 depends on RANDOMIZE_MEMORY 2163 default "0xa" if MEMORY_HOTPLUG 2164 default "0x0" 2165 range 0x1 0x40 if MEMORY_HOTPLUG 2166 range 0x0 0x40 2167 ---help--- 2168 Define the padding in terabytes added to the existing physical 2169 memory size during kernel memory randomization. It is useful 2170 for memory hotplug support but reduces the entropy available for 2171 address randomization. 2172 2173 If unsure, leave at the default value. 2174 2175config HOTPLUG_CPU 2176 bool "Support for hot-pluggable CPUs" 2177 depends on SMP 2178 ---help--- 2179 Say Y here to allow turning CPUs off and on. CPUs can be 2180 controlled through /sys/devices/system/cpu. 2181 ( Note: power management support will enable this option 2182 automatically on SMP systems. ) 2183 Say N if you want to disable CPU hotplug. 2184 2185config BOOTPARAM_HOTPLUG_CPU0 2186 bool "Set default setting of cpu0_hotpluggable" 2187 default n 2188 depends on HOTPLUG_CPU 2189 ---help--- 2190 Set whether default state of cpu0_hotpluggable is on or off. 2191 2192 Say Y here to enable CPU0 hotplug by default. If this switch 2193 is turned on, there is no need to give cpu0_hotplug kernel 2194 parameter and the CPU0 hotplug feature is enabled by default. 2195 2196 Please note: there are two known CPU0 dependencies if you want 2197 to enable the CPU0 hotplug feature either by this switch or by 2198 cpu0_hotplug kernel parameter. 2199 2200 First, resume from hibernate or suspend always starts from CPU0. 2201 So hibernate and suspend are prevented if CPU0 is offline. 2202 2203 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2204 offline if any interrupt can not migrate out of CPU0. There may 2205 be other CPU0 dependencies. 2206 2207 Please make sure the dependencies are under your control before 2208 you enable this feature. 2209 2210 Say N if you don't want to enable CPU0 hotplug feature by default. 2211 You still can enable the CPU0 hotplug feature at boot by kernel 2212 parameter cpu0_hotplug. 2213 2214config DEBUG_HOTPLUG_CPU0 2215 def_bool n 2216 prompt "Debug CPU0 hotplug" 2217 depends on HOTPLUG_CPU 2218 ---help--- 2219 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2220 soon as possible and boots up userspace with CPU0 offlined. User 2221 can online CPU0 back after boot time. 2222 2223 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2224 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2225 compilation or giving cpu0_hotplug kernel parameter at boot. 2226 2227 If unsure, say N. 2228 2229config COMPAT_VDSO 2230 def_bool n 2231 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2232 depends on COMPAT_32 2233 ---help--- 2234 Certain buggy versions of glibc will crash if they are 2235 presented with a 32-bit vDSO that is not mapped at the address 2236 indicated in its segment table. 2237 2238 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2239 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2240 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2241 the only released version with the bug, but OpenSUSE 9 2242 contains a buggy "glibc 2.3.2". 2243 2244 The symptom of the bug is that everything crashes on startup, saying: 2245 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2246 2247 Saying Y here changes the default value of the vdso32 boot 2248 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2249 This works around the glibc bug but hurts performance. 2250 2251 If unsure, say N: if you are compiling your own kernel, you 2252 are unlikely to be using a buggy version of glibc. 2253 2254choice 2255 prompt "vsyscall table for legacy applications" 2256 depends on X86_64 2257 default LEGACY_VSYSCALL_EMULATE 2258 help 2259 Legacy user code that does not know how to find the vDSO expects 2260 to be able to issue three syscalls by calling fixed addresses in 2261 kernel space. Since this location is not randomized with ASLR, 2262 it can be used to assist security vulnerability exploitation. 2263 2264 This setting can be changed at boot time via the kernel command 2265 line parameter vsyscall=[native|emulate|none]. 2266 2267 On a system with recent enough glibc (2.14 or newer) and no 2268 static binaries, you can say None without a performance penalty 2269 to improve security. 2270 2271 If unsure, select "Emulate". 2272 2273 config LEGACY_VSYSCALL_NATIVE 2274 bool "Native" 2275 help 2276 Actual executable code is located in the fixed vsyscall 2277 address mapping, implementing time() efficiently. Since 2278 this makes the mapping executable, it can be used during 2279 security vulnerability exploitation (traditionally as 2280 ROP gadgets). This configuration is not recommended. 2281 2282 config LEGACY_VSYSCALL_EMULATE 2283 bool "Emulate" 2284 help 2285 The kernel traps and emulates calls into the fixed 2286 vsyscall address mapping. This makes the mapping 2287 non-executable, but it still contains known contents, 2288 which could be used in certain rare security vulnerability 2289 exploits. This configuration is recommended when userspace 2290 still uses the vsyscall area. 2291 2292 config LEGACY_VSYSCALL_NONE 2293 bool "None" 2294 help 2295 There will be no vsyscall mapping at all. This will 2296 eliminate any risk of ASLR bypass due to the vsyscall 2297 fixed address mapping. Attempts to use the vsyscalls 2298 will be reported to dmesg, so that either old or 2299 malicious userspace programs can be identified. 2300 2301endchoice 2302 2303config CMDLINE_BOOL 2304 bool "Built-in kernel command line" 2305 ---help--- 2306 Allow for specifying boot arguments to the kernel at 2307 build time. On some systems (e.g. embedded ones), it is 2308 necessary or convenient to provide some or all of the 2309 kernel boot arguments with the kernel itself (that is, 2310 to not rely on the boot loader to provide them.) 2311 2312 To compile command line arguments into the kernel, 2313 set this option to 'Y', then fill in the 2314 boot arguments in CONFIG_CMDLINE. 2315 2316 Systems with fully functional boot loaders (i.e. non-embedded) 2317 should leave this option set to 'N'. 2318 2319config CMDLINE 2320 string "Built-in kernel command string" 2321 depends on CMDLINE_BOOL 2322 default "" 2323 ---help--- 2324 Enter arguments here that should be compiled into the kernel 2325 image and used at boot time. If the boot loader provides a 2326 command line at boot time, it is appended to this string to 2327 form the full kernel command line, when the system boots. 2328 2329 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2330 change this behavior. 2331 2332 In most cases, the command line (whether built-in or provided 2333 by the boot loader) should specify the device for the root 2334 file system. 2335 2336config CMDLINE_OVERRIDE 2337 bool "Built-in command line overrides boot loader arguments" 2338 depends on CMDLINE_BOOL 2339 ---help--- 2340 Set this option to 'Y' to have the kernel ignore the boot loader 2341 command line, and use ONLY the built-in command line. 2342 2343 This is used to work around broken boot loaders. This should 2344 be set to 'N' under normal conditions. 2345 2346config MODIFY_LDT_SYSCALL 2347 bool "Enable the LDT (local descriptor table)" if EXPERT 2348 default y 2349 ---help--- 2350 Linux can allow user programs to install a per-process x86 2351 Local Descriptor Table (LDT) using the modify_ldt(2) system 2352 call. This is required to run 16-bit or segmented code such as 2353 DOSEMU or some Wine programs. It is also used by some very old 2354 threading libraries. 2355 2356 Enabling this feature adds a small amount of overhead to 2357 context switches and increases the low-level kernel attack 2358 surface. Disabling it removes the modify_ldt(2) system call. 2359 2360 Saying 'N' here may make sense for embedded or server kernels. 2361 2362source "kernel/livepatch/Kconfig" 2363 2364endmenu 2365 2366config ARCH_HAS_ADD_PAGES 2367 def_bool y 2368 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2369 2370config ARCH_ENABLE_MEMORY_HOTPLUG 2371 def_bool y 2372 depends on X86_64 || (X86_32 && HIGHMEM) 2373 2374config ARCH_ENABLE_MEMORY_HOTREMOVE 2375 def_bool y 2376 depends on MEMORY_HOTPLUG 2377 2378config USE_PERCPU_NUMA_NODE_ID 2379 def_bool y 2380 depends on NUMA 2381 2382config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2383 def_bool y 2384 depends on X86_64 || X86_PAE 2385 2386config ARCH_ENABLE_HUGEPAGE_MIGRATION 2387 def_bool y 2388 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2389 2390config ARCH_ENABLE_THP_MIGRATION 2391 def_bool y 2392 depends on X86_64 && TRANSPARENT_HUGEPAGE 2393 2394menu "Power management and ACPI options" 2395 2396config ARCH_HIBERNATION_HEADER 2397 def_bool y 2398 depends on X86_64 && HIBERNATION 2399 2400source "kernel/power/Kconfig" 2401 2402source "drivers/acpi/Kconfig" 2403 2404source "drivers/sfi/Kconfig" 2405 2406config X86_APM_BOOT 2407 def_bool y 2408 depends on APM 2409 2410menuconfig APM 2411 tristate "APM (Advanced Power Management) BIOS support" 2412 depends on X86_32 && PM_SLEEP 2413 ---help--- 2414 APM is a BIOS specification for saving power using several different 2415 techniques. This is mostly useful for battery powered laptops with 2416 APM compliant BIOSes. If you say Y here, the system time will be 2417 reset after a RESUME operation, the /proc/apm device will provide 2418 battery status information, and user-space programs will receive 2419 notification of APM "events" (e.g. battery status change). 2420 2421 If you select "Y" here, you can disable actual use of the APM 2422 BIOS by passing the "apm=off" option to the kernel at boot time. 2423 2424 Note that the APM support is almost completely disabled for 2425 machines with more than one CPU. 2426 2427 In order to use APM, you will need supporting software. For location 2428 and more information, read <file:Documentation/power/apm-acpi.txt> 2429 and the Battery Powered Linux mini-HOWTO, available from 2430 <http://www.tldp.org/docs.html#howto>. 2431 2432 This driver does not spin down disk drives (see the hdparm(8) 2433 manpage ("man 8 hdparm") for that), and it doesn't turn off 2434 VESA-compliant "green" monitors. 2435 2436 This driver does not support the TI 4000M TravelMate and the ACER 2437 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2438 desktop machines also don't have compliant BIOSes, and this driver 2439 may cause those machines to panic during the boot phase. 2440 2441 Generally, if you don't have a battery in your machine, there isn't 2442 much point in using this driver and you should say N. If you get 2443 random kernel OOPSes or reboots that don't seem to be related to 2444 anything, try disabling/enabling this option (or disabling/enabling 2445 APM in your BIOS). 2446 2447 Some other things you should try when experiencing seemingly random, 2448 "weird" problems: 2449 2450 1) make sure that you have enough swap space and that it is 2451 enabled. 2452 2) pass the "no-hlt" option to the kernel 2453 3) switch on floating point emulation in the kernel and pass 2454 the "no387" option to the kernel 2455 4) pass the "floppy=nodma" option to the kernel 2456 5) pass the "mem=4M" option to the kernel (thereby disabling 2457 all but the first 4 MB of RAM) 2458 6) make sure that the CPU is not over clocked. 2459 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2460 8) disable the cache from your BIOS settings 2461 9) install a fan for the video card or exchange video RAM 2462 10) install a better fan for the CPU 2463 11) exchange RAM chips 2464 12) exchange the motherboard. 2465 2466 To compile this driver as a module, choose M here: the 2467 module will be called apm. 2468 2469if APM 2470 2471config APM_IGNORE_USER_SUSPEND 2472 bool "Ignore USER SUSPEND" 2473 ---help--- 2474 This option will ignore USER SUSPEND requests. On machines with a 2475 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2476 series notebooks, it is necessary to say Y because of a BIOS bug. 2477 2478config APM_DO_ENABLE 2479 bool "Enable PM at boot time" 2480 ---help--- 2481 Enable APM features at boot time. From page 36 of the APM BIOS 2482 specification: "When disabled, the APM BIOS does not automatically 2483 power manage devices, enter the Standby State, enter the Suspend 2484 State, or take power saving steps in response to CPU Idle calls." 2485 This driver will make CPU Idle calls when Linux is idle (unless this 2486 feature is turned off -- see "Do CPU IDLE calls", below). This 2487 should always save battery power, but more complicated APM features 2488 will be dependent on your BIOS implementation. You may need to turn 2489 this option off if your computer hangs at boot time when using APM 2490 support, or if it beeps continuously instead of suspending. Turn 2491 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2492 T400CDT. This is off by default since most machines do fine without 2493 this feature. 2494 2495config APM_CPU_IDLE 2496 depends on CPU_IDLE 2497 bool "Make CPU Idle calls when idle" 2498 ---help--- 2499 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2500 On some machines, this can activate improved power savings, such as 2501 a slowed CPU clock rate, when the machine is idle. These idle calls 2502 are made after the idle loop has run for some length of time (e.g., 2503 333 mS). On some machines, this will cause a hang at boot time or 2504 whenever the CPU becomes idle. (On machines with more than one CPU, 2505 this option does nothing.) 2506 2507config APM_DISPLAY_BLANK 2508 bool "Enable console blanking using APM" 2509 ---help--- 2510 Enable console blanking using the APM. Some laptops can use this to 2511 turn off the LCD backlight when the screen blanker of the Linux 2512 virtual console blanks the screen. Note that this is only used by 2513 the virtual console screen blanker, and won't turn off the backlight 2514 when using the X Window system. This also doesn't have anything to 2515 do with your VESA-compliant power-saving monitor. Further, this 2516 option doesn't work for all laptops -- it might not turn off your 2517 backlight at all, or it might print a lot of errors to the console, 2518 especially if you are using gpm. 2519 2520config APM_ALLOW_INTS 2521 bool "Allow interrupts during APM BIOS calls" 2522 ---help--- 2523 Normally we disable external interrupts while we are making calls to 2524 the APM BIOS as a measure to lessen the effects of a badly behaving 2525 BIOS implementation. The BIOS should reenable interrupts if it 2526 needs to. Unfortunately, some BIOSes do not -- especially those in 2527 many of the newer IBM Thinkpads. If you experience hangs when you 2528 suspend, try setting this to Y. Otherwise, say N. 2529 2530endif # APM 2531 2532source "drivers/cpufreq/Kconfig" 2533 2534source "drivers/cpuidle/Kconfig" 2535 2536source "drivers/idle/Kconfig" 2537 2538endmenu 2539 2540 2541menu "Bus options (PCI etc.)" 2542 2543config PCI 2544 bool "PCI support" 2545 default y 2546 ---help--- 2547 Find out whether you have a PCI motherboard. PCI is the name of a 2548 bus system, i.e. the way the CPU talks to the other stuff inside 2549 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or 2550 VESA. If you have PCI, say Y, otherwise N. 2551 2552choice 2553 prompt "PCI access mode" 2554 depends on X86_32 && PCI 2555 default PCI_GOANY 2556 ---help--- 2557 On PCI systems, the BIOS can be used to detect the PCI devices and 2558 determine their configuration. However, some old PCI motherboards 2559 have BIOS bugs and may crash if this is done. Also, some embedded 2560 PCI-based systems don't have any BIOS at all. Linux can also try to 2561 detect the PCI hardware directly without using the BIOS. 2562 2563 With this option, you can specify how Linux should detect the 2564 PCI devices. If you choose "BIOS", the BIOS will be used, 2565 if you choose "Direct", the BIOS won't be used, and if you 2566 choose "MMConfig", then PCI Express MMCONFIG will be used. 2567 If you choose "Any", the kernel will try MMCONFIG, then the 2568 direct access method and falls back to the BIOS if that doesn't 2569 work. If unsure, go with the default, which is "Any". 2570 2571config PCI_GOBIOS 2572 bool "BIOS" 2573 2574config PCI_GOMMCONFIG 2575 bool "MMConfig" 2576 2577config PCI_GODIRECT 2578 bool "Direct" 2579 2580config PCI_GOOLPC 2581 bool "OLPC XO-1" 2582 depends on OLPC 2583 2584config PCI_GOANY 2585 bool "Any" 2586 2587endchoice 2588 2589config PCI_BIOS 2590 def_bool y 2591 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2592 2593# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2594config PCI_DIRECT 2595 def_bool y 2596 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2597 2598config PCI_MMCONFIG 2599 def_bool y 2600 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY) 2601 2602config PCI_OLPC 2603 def_bool y 2604 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2605 2606config PCI_XEN 2607 def_bool y 2608 depends on PCI && XEN 2609 select SWIOTLB_XEN 2610 2611config PCI_DOMAINS 2612 def_bool y 2613 depends on PCI 2614 2615config PCI_MMCONFIG 2616 bool "Support mmconfig PCI config space access" 2617 depends on X86_64 && PCI && ACPI 2618 2619config PCI_CNB20LE_QUIRK 2620 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2621 depends on PCI 2622 help 2623 Read the PCI windows out of the CNB20LE host bridge. This allows 2624 PCI hotplug to work on systems with the CNB20LE chipset which do 2625 not have ACPI. 2626 2627 There's no public spec for this chipset, and this functionality 2628 is known to be incomplete. 2629 2630 You should say N unless you know you need this. 2631 2632source "drivers/pci/Kconfig" 2633 2634config ISA_BUS 2635 bool "ISA-style bus support on modern systems" if EXPERT 2636 select ISA_BUS_API 2637 help 2638 Enables ISA-style drivers on modern systems. This is necessary to 2639 support PC/104 devices on X86_64 platforms. 2640 2641 If unsure, say N. 2642 2643# x86_64 have no ISA slots, but can have ISA-style DMA. 2644config ISA_DMA_API 2645 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2646 default y 2647 help 2648 Enables ISA-style DMA support for devices requiring such controllers. 2649 If unsure, say Y. 2650 2651if X86_32 2652 2653config ISA 2654 bool "ISA support" 2655 ---help--- 2656 Find out whether you have ISA slots on your motherboard. ISA is the 2657 name of a bus system, i.e. the way the CPU talks to the other stuff 2658 inside your box. Other bus systems are PCI, EISA, MicroChannel 2659 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2660 newer boards don't support it. If you have ISA, say Y, otherwise N. 2661 2662config EISA 2663 bool "EISA support" 2664 depends on ISA 2665 ---help--- 2666 The Extended Industry Standard Architecture (EISA) bus was 2667 developed as an open alternative to the IBM MicroChannel bus. 2668 2669 The EISA bus provided some of the features of the IBM MicroChannel 2670 bus while maintaining backward compatibility with cards made for 2671 the older ISA bus. The EISA bus saw limited use between 1988 and 2672 1995 when it was made obsolete by the PCI bus. 2673 2674 Say Y here if you are building a kernel for an EISA-based machine. 2675 2676 Otherwise, say N. 2677 2678source "drivers/eisa/Kconfig" 2679 2680config SCx200 2681 tristate "NatSemi SCx200 support" 2682 ---help--- 2683 This provides basic support for National Semiconductor's 2684 (now AMD's) Geode processors. The driver probes for the 2685 PCI-IDs of several on-chip devices, so its a good dependency 2686 for other scx200_* drivers. 2687 2688 If compiled as a module, the driver is named scx200. 2689 2690config SCx200HR_TIMER 2691 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2692 depends on SCx200 2693 default y 2694 ---help--- 2695 This driver provides a clocksource built upon the on-chip 2696 27MHz high-resolution timer. Its also a workaround for 2697 NSC Geode SC-1100's buggy TSC, which loses time when the 2698 processor goes idle (as is done by the scheduler). The 2699 other workaround is idle=poll boot option. 2700 2701config OLPC 2702 bool "One Laptop Per Child support" 2703 depends on !X86_PAE 2704 select GPIOLIB 2705 select OF 2706 select OF_PROMTREE 2707 select IRQ_DOMAIN 2708 ---help--- 2709 Add support for detecting the unique features of the OLPC 2710 XO hardware. 2711 2712config OLPC_XO1_PM 2713 bool "OLPC XO-1 Power Management" 2714 depends on OLPC && MFD_CS5535 && PM_SLEEP 2715 select MFD_CORE 2716 ---help--- 2717 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2718 2719config OLPC_XO1_RTC 2720 bool "OLPC XO-1 Real Time Clock" 2721 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2722 ---help--- 2723 Add support for the XO-1 real time clock, which can be used as a 2724 programmable wakeup source. 2725 2726config OLPC_XO1_SCI 2727 bool "OLPC XO-1 SCI extras" 2728 depends on OLPC && OLPC_XO1_PM 2729 depends on INPUT=y 2730 select POWER_SUPPLY 2731 select GPIO_CS5535 2732 select MFD_CORE 2733 ---help--- 2734 Add support for SCI-based features of the OLPC XO-1 laptop: 2735 - EC-driven system wakeups 2736 - Power button 2737 - Ebook switch 2738 - Lid switch 2739 - AC adapter status updates 2740 - Battery status updates 2741 2742config OLPC_XO15_SCI 2743 bool "OLPC XO-1.5 SCI extras" 2744 depends on OLPC && ACPI 2745 select POWER_SUPPLY 2746 ---help--- 2747 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2748 - EC-driven system wakeups 2749 - AC adapter status updates 2750 - Battery status updates 2751 2752config ALIX 2753 bool "PCEngines ALIX System Support (LED setup)" 2754 select GPIOLIB 2755 ---help--- 2756 This option enables system support for the PCEngines ALIX. 2757 At present this just sets up LEDs for GPIO control on 2758 ALIX2/3/6 boards. However, other system specific setup should 2759 get added here. 2760 2761 Note: You must still enable the drivers for GPIO and LED support 2762 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2763 2764 Note: You have to set alix.force=1 for boards with Award BIOS. 2765 2766config NET5501 2767 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2768 select GPIOLIB 2769 ---help--- 2770 This option enables system support for the Soekris Engineering net5501. 2771 2772config GEOS 2773 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2774 select GPIOLIB 2775 depends on DMI 2776 ---help--- 2777 This option enables system support for the Traverse Technologies GEOS. 2778 2779config TS5500 2780 bool "Technologic Systems TS-5500 platform support" 2781 depends on MELAN 2782 select CHECK_SIGNATURE 2783 select NEW_LEDS 2784 select LEDS_CLASS 2785 ---help--- 2786 This option enables system support for the Technologic Systems TS-5500. 2787 2788endif # X86_32 2789 2790config AMD_NB 2791 def_bool y 2792 depends on CPU_SUP_AMD && PCI 2793 2794source "drivers/pcmcia/Kconfig" 2795 2796config RAPIDIO 2797 tristate "RapidIO support" 2798 depends on PCI 2799 default n 2800 help 2801 If enabled this option will include drivers and the core 2802 infrastructure code to support RapidIO interconnect devices. 2803 2804source "drivers/rapidio/Kconfig" 2805 2806config X86_SYSFB 2807 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2808 help 2809 Firmwares often provide initial graphics framebuffers so the BIOS, 2810 bootloader or kernel can show basic video-output during boot for 2811 user-guidance and debugging. Historically, x86 used the VESA BIOS 2812 Extensions and EFI-framebuffers for this, which are mostly limited 2813 to x86. 2814 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2815 framebuffers so the new generic system-framebuffer drivers can be 2816 used on x86. If the framebuffer is not compatible with the generic 2817 modes, it is adverticed as fallback platform framebuffer so legacy 2818 drivers like efifb, vesafb and uvesafb can pick it up. 2819 If this option is not selected, all system framebuffers are always 2820 marked as fallback platform framebuffers as usual. 2821 2822 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2823 not be able to pick up generic system framebuffers if this option 2824 is selected. You are highly encouraged to enable simplefb as 2825 replacement if you select this option. simplefb can correctly deal 2826 with generic system framebuffers. But you should still keep vesafb 2827 and others enabled as fallback if a system framebuffer is 2828 incompatible with simplefb. 2829 2830 If unsure, say Y. 2831 2832endmenu 2833 2834 2835menu "Executable file formats / Emulations" 2836 2837source "fs/Kconfig.binfmt" 2838 2839config IA32_EMULATION 2840 bool "IA32 Emulation" 2841 depends on X86_64 2842 select ARCH_WANT_OLD_COMPAT_IPC 2843 select BINFMT_ELF 2844 select COMPAT_BINFMT_ELF 2845 select COMPAT_OLD_SIGACTION 2846 ---help--- 2847 Include code to run legacy 32-bit programs under a 2848 64-bit kernel. You should likely turn this on, unless you're 2849 100% sure that you don't have any 32-bit programs left. 2850 2851config IA32_AOUT 2852 tristate "IA32 a.out support" 2853 depends on IA32_EMULATION 2854 ---help--- 2855 Support old a.out binaries in the 32bit emulation. 2856 2857config X86_X32 2858 bool "x32 ABI for 64-bit mode" 2859 depends on X86_64 2860 ---help--- 2861 Include code to run binaries for the x32 native 32-bit ABI 2862 for 64-bit processors. An x32 process gets access to the 2863 full 64-bit register file and wide data path while leaving 2864 pointers at 32 bits for smaller memory footprint. 2865 2866 You will need a recent binutils (2.22 or later) with 2867 elf32_x86_64 support enabled to compile a kernel with this 2868 option set. 2869 2870config COMPAT_32 2871 def_bool y 2872 depends on IA32_EMULATION || X86_32 2873 select HAVE_UID16 2874 select OLD_SIGSUSPEND3 2875 2876config COMPAT 2877 def_bool y 2878 depends on IA32_EMULATION || X86_X32 2879 2880if COMPAT 2881config COMPAT_FOR_U64_ALIGNMENT 2882 def_bool y 2883 2884config SYSVIPC_COMPAT 2885 def_bool y 2886 depends on SYSVIPC 2887endif 2888 2889endmenu 2890 2891 2892config HAVE_ATOMIC_IOMAP 2893 def_bool y 2894 depends on X86_32 2895 2896config X86_DEV_DMA_OPS 2897 bool 2898 depends on X86_64 || STA2X11 2899 2900config X86_DMA_REMAP 2901 bool 2902 depends on STA2X11 2903 2904config HAVE_GENERIC_GUP 2905 def_bool y 2906 2907source "net/Kconfig" 2908 2909source "drivers/Kconfig" 2910 2911source "drivers/firmware/Kconfig" 2912 2913source "fs/Kconfig" 2914 2915source "arch/x86/Kconfig.debug" 2916 2917source "security/Kconfig" 2918 2919source "crypto/Kconfig" 2920 2921source "arch/x86/kvm/Kconfig" 2922 2923source "lib/Kconfig" 2924