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_THREAD_STRUCT_WHITELIST 120 select HAVE_ARCH_TRACEHOOK 121 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 122 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 123 select HAVE_ARCH_VMAP_STACK if X86_64 124 select HAVE_ARCH_WITHIN_STACK_FRAMES 125 select HAVE_CC_STACKPROTECTOR 126 select HAVE_CMPXCHG_DOUBLE 127 select HAVE_CMPXCHG_LOCAL 128 select HAVE_CONTEXT_TRACKING if X86_64 129 select HAVE_COPY_THREAD_TLS 130 select HAVE_C_RECORDMCOUNT 131 select HAVE_DEBUG_KMEMLEAK 132 select HAVE_DEBUG_STACKOVERFLOW 133 select HAVE_DMA_API_DEBUG 134 select HAVE_DMA_CONTIGUOUS 135 select HAVE_DYNAMIC_FTRACE 136 select HAVE_DYNAMIC_FTRACE_WITH_REGS 137 select HAVE_EBPF_JIT if X86_64 138 select HAVE_EFFICIENT_UNALIGNED_ACCESS 139 select HAVE_EXIT_THREAD 140 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 141 select HAVE_FTRACE_MCOUNT_RECORD 142 select HAVE_FUNCTION_GRAPH_TRACER 143 select HAVE_FUNCTION_TRACER 144 select HAVE_GCC_PLUGINS 145 select HAVE_HW_BREAKPOINT 146 select HAVE_IDE 147 select HAVE_IOREMAP_PROT 148 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 149 select HAVE_IRQ_TIME_ACCOUNTING 150 select HAVE_KERNEL_BZIP2 151 select HAVE_KERNEL_GZIP 152 select HAVE_KERNEL_LZ4 153 select HAVE_KERNEL_LZMA 154 select HAVE_KERNEL_LZO 155 select HAVE_KERNEL_XZ 156 select HAVE_KPROBES 157 select HAVE_KPROBES_ON_FTRACE 158 select HAVE_FUNCTION_ERROR_INJECTION 159 select HAVE_KRETPROBES 160 select HAVE_KVM 161 select HAVE_LIVEPATCH if X86_64 162 select HAVE_MEMBLOCK 163 select HAVE_MEMBLOCK_NODE_MAP 164 select HAVE_MIXED_BREAKPOINTS_REGS 165 select HAVE_MOD_ARCH_SPECIFIC 166 select HAVE_NMI 167 select HAVE_OPROFILE 168 select HAVE_OPTPROBES 169 select HAVE_PCSPKR_PLATFORM 170 select HAVE_PERF_EVENTS 171 select HAVE_PERF_EVENTS_NMI 172 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 173 select HAVE_PERF_REGS 174 select HAVE_PERF_USER_STACK_DUMP 175 select HAVE_RCU_TABLE_FREE 176 select HAVE_REGS_AND_STACK_ACCESS_API 177 select HAVE_RELIABLE_STACKTRACE if X86_64 && UNWINDER_FRAME_POINTER && STACK_VALIDATION 178 select HAVE_STACK_VALIDATION if X86_64 179 select HAVE_SYSCALL_TRACEPOINTS 180 select HAVE_UNSTABLE_SCHED_CLOCK 181 select HAVE_USER_RETURN_NOTIFIER 182 select IRQ_FORCED_THREADING 183 select PCI_LOCKLESS_CONFIG 184 select PERF_EVENTS 185 select RTC_LIB 186 select RTC_MC146818_LIB 187 select SPARSE_IRQ 188 select SRCU 189 select SYSCTL_EXCEPTION_TRACE 190 select THREAD_INFO_IN_TASK 191 select USER_STACKTRACE_SUPPORT 192 select VIRT_TO_BUS 193 select X86_FEATURE_NAMES if PROC_FS 194 195config INSTRUCTION_DECODER 196 def_bool y 197 depends on KPROBES || PERF_EVENTS || UPROBES 198 199config OUTPUT_FORMAT 200 string 201 default "elf32-i386" if X86_32 202 default "elf64-x86-64" if X86_64 203 204config ARCH_DEFCONFIG 205 string 206 default "arch/x86/configs/i386_defconfig" if X86_32 207 default "arch/x86/configs/x86_64_defconfig" if X86_64 208 209config LOCKDEP_SUPPORT 210 def_bool y 211 212config STACKTRACE_SUPPORT 213 def_bool y 214 215config MMU 216 def_bool y 217 218config ARCH_MMAP_RND_BITS_MIN 219 default 28 if 64BIT 220 default 8 221 222config ARCH_MMAP_RND_BITS_MAX 223 default 32 if 64BIT 224 default 16 225 226config ARCH_MMAP_RND_COMPAT_BITS_MIN 227 default 8 228 229config ARCH_MMAP_RND_COMPAT_BITS_MAX 230 default 16 231 232config SBUS 233 bool 234 235config NEED_DMA_MAP_STATE 236 def_bool y 237 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB 238 239config NEED_SG_DMA_LENGTH 240 def_bool y 241 242config GENERIC_ISA_DMA 243 def_bool y 244 depends on ISA_DMA_API 245 246config GENERIC_BUG 247 def_bool y 248 depends on BUG 249 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 250 251config GENERIC_BUG_RELATIVE_POINTERS 252 bool 253 254config GENERIC_HWEIGHT 255 def_bool y 256 257config ARCH_MAY_HAVE_PC_FDC 258 def_bool y 259 depends on ISA_DMA_API 260 261config RWSEM_XCHGADD_ALGORITHM 262 def_bool y 263 264config GENERIC_CALIBRATE_DELAY 265 def_bool y 266 267config ARCH_HAS_CPU_RELAX 268 def_bool y 269 270config ARCH_HAS_CACHE_LINE_SIZE 271 def_bool y 272 273config HAVE_SETUP_PER_CPU_AREA 274 def_bool y 275 276config NEED_PER_CPU_EMBED_FIRST_CHUNK 277 def_bool y 278 279config NEED_PER_CPU_PAGE_FIRST_CHUNK 280 def_bool y 281 282config ARCH_HIBERNATION_POSSIBLE 283 def_bool y 284 285config ARCH_SUSPEND_POSSIBLE 286 def_bool y 287 288config ARCH_WANT_HUGE_PMD_SHARE 289 def_bool y 290 291config ARCH_WANT_GENERAL_HUGETLB 292 def_bool y 293 294config ZONE_DMA32 295 def_bool y if X86_64 296 297config AUDIT_ARCH 298 def_bool y if X86_64 299 300config ARCH_SUPPORTS_OPTIMIZED_INLINING 301 def_bool y 302 303config ARCH_SUPPORTS_DEBUG_PAGEALLOC 304 def_bool y 305 306config KASAN_SHADOW_OFFSET 307 hex 308 depends on KASAN 309 default 0xdffffc0000000000 310 311config HAVE_INTEL_TXT 312 def_bool y 313 depends on INTEL_IOMMU && ACPI 314 315config X86_32_SMP 316 def_bool y 317 depends on X86_32 && SMP 318 319config X86_64_SMP 320 def_bool y 321 depends on X86_64 && SMP 322 323config X86_32_LAZY_GS 324 def_bool y 325 depends on X86_32 && !CC_STACKPROTECTOR 326 327config ARCH_SUPPORTS_UPROBES 328 def_bool y 329 330config FIX_EARLYCON_MEM 331 def_bool y 332 333config PGTABLE_LEVELS 334 int 335 default 5 if X86_5LEVEL 336 default 4 if X86_64 337 default 3 if X86_PAE 338 default 2 339 340source "init/Kconfig" 341source "kernel/Kconfig.freezer" 342 343menu "Processor type and features" 344 345config ZONE_DMA 346 bool "DMA memory allocation support" if EXPERT 347 default y 348 help 349 DMA memory allocation support allows devices with less than 32-bit 350 addressing to allocate within the first 16MB of address space. 351 Disable if no such devices will be used. 352 353 If unsure, say Y. 354 355config SMP 356 bool "Symmetric multi-processing support" 357 ---help--- 358 This enables support for systems with more than one CPU. If you have 359 a system with only one CPU, say N. If you have a system with more 360 than one CPU, say Y. 361 362 If you say N here, the kernel will run on uni- and multiprocessor 363 machines, but will use only one CPU of a multiprocessor machine. If 364 you say Y here, the kernel will run on many, but not all, 365 uniprocessor machines. On a uniprocessor machine, the kernel 366 will run faster if you say N here. 367 368 Note that if you say Y here and choose architecture "586" or 369 "Pentium" under "Processor family", the kernel will not work on 486 370 architectures. Similarly, multiprocessor kernels for the "PPro" 371 architecture may not work on all Pentium based boards. 372 373 People using multiprocessor machines who say Y here should also say 374 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 375 Management" code will be disabled if you say Y here. 376 377 See also <file:Documentation/x86/i386/IO-APIC.txt>, 378 <file:Documentation/lockup-watchdogs.txt> and the SMP-HOWTO available at 379 <http://www.tldp.org/docs.html#howto>. 380 381 If you don't know what to do here, say N. 382 383config X86_FEATURE_NAMES 384 bool "Processor feature human-readable names" if EMBEDDED 385 default y 386 ---help--- 387 This option compiles in a table of x86 feature bits and corresponding 388 names. This is required to support /proc/cpuinfo and a few kernel 389 messages. You can disable this to save space, at the expense of 390 making those few kernel messages show numeric feature bits instead. 391 392 If in doubt, say Y. 393 394config X86_FAST_FEATURE_TESTS 395 bool "Fast CPU feature tests" if EMBEDDED 396 default y 397 ---help--- 398 Some fast-paths in the kernel depend on the capabilities of the CPU. 399 Say Y here for the kernel to patch in the appropriate code at runtime 400 based on the capabilities of the CPU. The infrastructure for patching 401 code at runtime takes up some additional space; space-constrained 402 embedded systems may wish to say N here to produce smaller, slightly 403 slower code. 404 405config X86_X2APIC 406 bool "Support x2apic" 407 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 408 ---help--- 409 This enables x2apic support on CPUs that have this feature. 410 411 This allows 32-bit apic IDs (so it can support very large systems), 412 and accesses the local apic via MSRs not via mmio. 413 414 If you don't know what to do here, say N. 415 416config X86_MPPARSE 417 bool "Enable MPS table" if ACPI || SFI 418 default y 419 depends on X86_LOCAL_APIC 420 ---help--- 421 For old smp systems that do not have proper acpi support. Newer systems 422 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 423 424config X86_BIGSMP 425 bool "Support for big SMP systems with more than 8 CPUs" 426 depends on X86_32 && SMP 427 ---help--- 428 This option is needed for the systems that have more than 8 CPUs 429 430config GOLDFISH 431 def_bool y 432 depends on X86_GOLDFISH 433 434config RETPOLINE 435 bool "Avoid speculative indirect branches in kernel" 436 default y 437 help 438 Compile kernel with the retpoline compiler options to guard against 439 kernel-to-user data leaks by avoiding speculative indirect 440 branches. Requires a compiler with -mindirect-branch=thunk-extern 441 support for full protection. The kernel may run slower. 442 443 Without compiler support, at least indirect branches in assembler 444 code are eliminated. Since this includes the syscall entry path, 445 it is not entirely pointless. 446 447config INTEL_RDT 448 bool "Intel Resource Director Technology support" 449 default n 450 depends on X86 && CPU_SUP_INTEL 451 select KERNFS 452 help 453 Select to enable resource allocation and monitoring which are 454 sub-features of Intel Resource Director Technology(RDT). More 455 information about RDT can be found in the Intel x86 456 Architecture Software Developer Manual. 457 458 Say N if unsure. 459 460if X86_32 461config X86_EXTENDED_PLATFORM 462 bool "Support for extended (non-PC) x86 platforms" 463 default y 464 ---help--- 465 If you disable this option then the kernel will only support 466 standard PC platforms. (which covers the vast majority of 467 systems out there.) 468 469 If you enable this option then you'll be able to select support 470 for the following (non-PC) 32 bit x86 platforms: 471 Goldfish (Android emulator) 472 AMD Elan 473 RDC R-321x SoC 474 SGI 320/540 (Visual Workstation) 475 STA2X11-based (e.g. Northville) 476 Moorestown MID devices 477 478 If you have one of these systems, or if you want to build a 479 generic distribution kernel, say Y here - otherwise say N. 480endif 481 482if X86_64 483config X86_EXTENDED_PLATFORM 484 bool "Support for extended (non-PC) x86 platforms" 485 default y 486 ---help--- 487 If you disable this option then the kernel will only support 488 standard PC platforms. (which covers the vast majority of 489 systems out there.) 490 491 If you enable this option then you'll be able to select support 492 for the following (non-PC) 64 bit x86 platforms: 493 Numascale NumaChip 494 ScaleMP vSMP 495 SGI Ultraviolet 496 497 If you have one of these systems, or if you want to build a 498 generic distribution kernel, say Y here - otherwise say N. 499endif 500# This is an alphabetically sorted list of 64 bit extended platforms 501# Please maintain the alphabetic order if and when there are additions 502config X86_NUMACHIP 503 bool "Numascale NumaChip" 504 depends on X86_64 505 depends on X86_EXTENDED_PLATFORM 506 depends on NUMA 507 depends on SMP 508 depends on X86_X2APIC 509 depends on PCI_MMCONFIG 510 ---help--- 511 Adds support for Numascale NumaChip large-SMP systems. Needed to 512 enable more than ~168 cores. 513 If you don't have one of these, you should say N here. 514 515config X86_VSMP 516 bool "ScaleMP vSMP" 517 select HYPERVISOR_GUEST 518 select PARAVIRT 519 depends on X86_64 && PCI 520 depends on X86_EXTENDED_PLATFORM 521 depends on SMP 522 ---help--- 523 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 524 supposed to run on these EM64T-based machines. Only choose this option 525 if you have one of these machines. 526 527config X86_UV 528 bool "SGI Ultraviolet" 529 depends on X86_64 530 depends on X86_EXTENDED_PLATFORM 531 depends on NUMA 532 depends on EFI 533 depends on X86_X2APIC 534 depends on PCI 535 ---help--- 536 This option is needed in order to support SGI Ultraviolet systems. 537 If you don't have one of these, you should say N here. 538 539# Following is an alphabetically sorted list of 32 bit extended platforms 540# Please maintain the alphabetic order if and when there are additions 541 542config X86_GOLDFISH 543 bool "Goldfish (Virtual Platform)" 544 depends on X86_EXTENDED_PLATFORM 545 ---help--- 546 Enable support for the Goldfish virtual platform used primarily 547 for Android development. Unless you are building for the Android 548 Goldfish emulator say N here. 549 550config X86_INTEL_CE 551 bool "CE4100 TV platform" 552 depends on PCI 553 depends on PCI_GODIRECT 554 depends on X86_IO_APIC 555 depends on X86_32 556 depends on X86_EXTENDED_PLATFORM 557 select X86_REBOOTFIXUPS 558 select OF 559 select OF_EARLY_FLATTREE 560 ---help--- 561 Select for the Intel CE media processor (CE4100) SOC. 562 This option compiles in support for the CE4100 SOC for settop 563 boxes and media devices. 564 565config X86_INTEL_MID 566 bool "Intel MID platform support" 567 depends on X86_EXTENDED_PLATFORM 568 depends on X86_PLATFORM_DEVICES 569 depends on PCI 570 depends on X86_64 || (PCI_GOANY && X86_32) 571 depends on X86_IO_APIC 572 select SFI 573 select I2C 574 select DW_APB_TIMER 575 select APB_TIMER 576 select INTEL_SCU_IPC 577 select MFD_INTEL_MSIC 578 ---help--- 579 Select to build a kernel capable of supporting Intel MID (Mobile 580 Internet Device) platform systems which do not have the PCI legacy 581 interfaces. If you are building for a PC class system say N here. 582 583 Intel MID platforms are based on an Intel processor and chipset which 584 consume less power than most of the x86 derivatives. 585 586config X86_INTEL_QUARK 587 bool "Intel Quark platform support" 588 depends on X86_32 589 depends on X86_EXTENDED_PLATFORM 590 depends on X86_PLATFORM_DEVICES 591 depends on X86_TSC 592 depends on PCI 593 depends on PCI_GOANY 594 depends on X86_IO_APIC 595 select IOSF_MBI 596 select INTEL_IMR 597 select COMMON_CLK 598 ---help--- 599 Select to include support for Quark X1000 SoC. 600 Say Y here if you have a Quark based system such as the Arduino 601 compatible Intel Galileo. 602 603config X86_INTEL_LPSS 604 bool "Intel Low Power Subsystem Support" 605 depends on X86 && ACPI 606 select COMMON_CLK 607 select PINCTRL 608 select IOSF_MBI 609 ---help--- 610 Select to build support for Intel Low Power Subsystem such as 611 found on Intel Lynxpoint PCH. Selecting this option enables 612 things like clock tree (common clock framework) and pincontrol 613 which are needed by the LPSS peripheral drivers. 614 615config X86_AMD_PLATFORM_DEVICE 616 bool "AMD ACPI2Platform devices support" 617 depends on ACPI 618 select COMMON_CLK 619 select PINCTRL 620 ---help--- 621 Select to interpret AMD specific ACPI device to platform device 622 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 623 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 624 implemented under PINCTRL subsystem. 625 626config IOSF_MBI 627 tristate "Intel SoC IOSF Sideband support for SoC platforms" 628 depends on PCI 629 ---help--- 630 This option enables sideband register access support for Intel SoC 631 platforms. On these platforms the IOSF sideband is used in lieu of 632 MSR's for some register accesses, mostly but not limited to thermal 633 and power. Drivers may query the availability of this device to 634 determine if they need the sideband in order to work on these 635 platforms. The sideband is available on the following SoC products. 636 This list is not meant to be exclusive. 637 - BayTrail 638 - Braswell 639 - Quark 640 641 You should say Y if you are running a kernel on one of these SoC's. 642 643config IOSF_MBI_DEBUG 644 bool "Enable IOSF sideband access through debugfs" 645 depends on IOSF_MBI && DEBUG_FS 646 ---help--- 647 Select this option to expose the IOSF sideband access registers (MCR, 648 MDR, MCRX) through debugfs to write and read register information from 649 different units on the SoC. This is most useful for obtaining device 650 state information for debug and analysis. As this is a general access 651 mechanism, users of this option would have specific knowledge of the 652 device they want to access. 653 654 If you don't require the option or are in doubt, say N. 655 656config X86_RDC321X 657 bool "RDC R-321x SoC" 658 depends on X86_32 659 depends on X86_EXTENDED_PLATFORM 660 select M486 661 select X86_REBOOTFIXUPS 662 ---help--- 663 This option is needed for RDC R-321x system-on-chip, also known 664 as R-8610-(G). 665 If you don't have one of these chips, you should say N here. 666 667config X86_32_NON_STANDARD 668 bool "Support non-standard 32-bit SMP architectures" 669 depends on X86_32 && SMP 670 depends on X86_EXTENDED_PLATFORM 671 ---help--- 672 This option compiles in the bigsmp and STA2X11 default 673 subarchitectures. It is intended for a generic binary 674 kernel. If you select them all, kernel will probe it one by 675 one and will fallback to default. 676 677# Alphabetically sorted list of Non standard 32 bit platforms 678 679config X86_SUPPORTS_MEMORY_FAILURE 680 def_bool y 681 # MCE code calls memory_failure(): 682 depends on X86_MCE 683 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 684 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 685 depends on X86_64 || !SPARSEMEM 686 select ARCH_SUPPORTS_MEMORY_FAILURE 687 688config STA2X11 689 bool "STA2X11 Companion Chip Support" 690 depends on X86_32_NON_STANDARD && PCI 691 select X86_DEV_DMA_OPS 692 select X86_DMA_REMAP 693 select SWIOTLB 694 select MFD_STA2X11 695 select GPIOLIB 696 default n 697 ---help--- 698 This adds support for boards based on the STA2X11 IO-Hub, 699 a.k.a. "ConneXt". The chip is used in place of the standard 700 PC chipset, so all "standard" peripherals are missing. If this 701 option is selected the kernel will still be able to boot on 702 standard PC machines. 703 704config X86_32_IRIS 705 tristate "Eurobraille/Iris poweroff module" 706 depends on X86_32 707 ---help--- 708 The Iris machines from EuroBraille do not have APM or ACPI support 709 to shut themselves down properly. A special I/O sequence is 710 needed to do so, which is what this module does at 711 kernel shutdown. 712 713 This is only for Iris machines from EuroBraille. 714 715 If unused, say N. 716 717config SCHED_OMIT_FRAME_POINTER 718 def_bool y 719 prompt "Single-depth WCHAN output" 720 depends on X86 721 ---help--- 722 Calculate simpler /proc/<PID>/wchan values. If this option 723 is disabled then wchan values will recurse back to the 724 caller function. This provides more accurate wchan values, 725 at the expense of slightly more scheduling overhead. 726 727 If in doubt, say "Y". 728 729menuconfig HYPERVISOR_GUEST 730 bool "Linux guest support" 731 ---help--- 732 Say Y here to enable options for running Linux under various hyper- 733 visors. This option enables basic hypervisor detection and platform 734 setup. 735 736 If you say N, all options in this submenu will be skipped and 737 disabled, and Linux guest support won't be built in. 738 739if HYPERVISOR_GUEST 740 741config PARAVIRT 742 bool "Enable paravirtualization code" 743 ---help--- 744 This changes the kernel so it can modify itself when it is run 745 under a hypervisor, potentially improving performance significantly 746 over full virtualization. However, when run without a hypervisor 747 the kernel is theoretically slower and slightly larger. 748 749config PARAVIRT_DEBUG 750 bool "paravirt-ops debugging" 751 depends on PARAVIRT && DEBUG_KERNEL 752 ---help--- 753 Enable to debug paravirt_ops internals. Specifically, BUG if 754 a paravirt_op is missing when it is called. 755 756config PARAVIRT_SPINLOCKS 757 bool "Paravirtualization layer for spinlocks" 758 depends on PARAVIRT && SMP 759 ---help--- 760 Paravirtualized spinlocks allow a pvops backend to replace the 761 spinlock implementation with something virtualization-friendly 762 (for example, block the virtual CPU rather than spinning). 763 764 It has a minimal impact on native kernels and gives a nice performance 765 benefit on paravirtualized KVM / Xen kernels. 766 767 If you are unsure how to answer this question, answer Y. 768 769config QUEUED_LOCK_STAT 770 bool "Paravirt queued spinlock statistics" 771 depends on PARAVIRT_SPINLOCKS && DEBUG_FS 772 ---help--- 773 Enable the collection of statistical data on the slowpath 774 behavior of paravirtualized queued spinlocks and report 775 them on debugfs. 776 777source "arch/x86/xen/Kconfig" 778 779config KVM_GUEST 780 bool "KVM Guest support (including kvmclock)" 781 depends on PARAVIRT 782 select PARAVIRT_CLOCK 783 default y 784 ---help--- 785 This option enables various optimizations for running under the KVM 786 hypervisor. It includes a paravirtualized clock, so that instead 787 of relying on a PIT (or probably other) emulation by the 788 underlying device model, the host provides the guest with 789 timing infrastructure such as time of day, and system time 790 791config KVM_DEBUG_FS 792 bool "Enable debug information for KVM Guests in debugfs" 793 depends on KVM_GUEST && DEBUG_FS 794 default n 795 ---help--- 796 This option enables collection of various statistics for KVM guest. 797 Statistics are displayed in debugfs filesystem. Enabling this option 798 may incur significant overhead. 799 800config PARAVIRT_TIME_ACCOUNTING 801 bool "Paravirtual steal time accounting" 802 depends on PARAVIRT 803 default n 804 ---help--- 805 Select this option to enable fine granularity task steal time 806 accounting. Time spent executing other tasks in parallel with 807 the current vCPU is discounted from the vCPU power. To account for 808 that, there can be a small performance impact. 809 810 If in doubt, say N here. 811 812config PARAVIRT_CLOCK 813 bool 814 815config JAILHOUSE_GUEST 816 bool "Jailhouse non-root cell support" 817 depends on X86_64 && PCI 818 select X86_PM_TIMER 819 ---help--- 820 This option allows to run Linux as guest in a Jailhouse non-root 821 cell. You can leave this option disabled if you only want to start 822 Jailhouse and run Linux afterwards in the root cell. 823 824endif #HYPERVISOR_GUEST 825 826config NO_BOOTMEM 827 def_bool y 828 829source "arch/x86/Kconfig.cpu" 830 831config HPET_TIMER 832 def_bool X86_64 833 prompt "HPET Timer Support" if X86_32 834 ---help--- 835 Use the IA-PC HPET (High Precision Event Timer) to manage 836 time in preference to the PIT and RTC, if a HPET is 837 present. 838 HPET is the next generation timer replacing legacy 8254s. 839 The HPET provides a stable time base on SMP 840 systems, unlike the TSC, but it is more expensive to access, 841 as it is off-chip. The interface used is documented 842 in the HPET spec, revision 1. 843 844 You can safely choose Y here. However, HPET will only be 845 activated if the platform and the BIOS support this feature. 846 Otherwise the 8254 will be used for timing services. 847 848 Choose N to continue using the legacy 8254 timer. 849 850config HPET_EMULATE_RTC 851 def_bool y 852 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 853 854config APB_TIMER 855 def_bool y if X86_INTEL_MID 856 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 857 select DW_APB_TIMER 858 depends on X86_INTEL_MID && SFI 859 help 860 APB timer is the replacement for 8254, HPET on X86 MID platforms. 861 The APBT provides a stable time base on SMP 862 systems, unlike the TSC, but it is more expensive to access, 863 as it is off-chip. APB timers are always running regardless of CPU 864 C states, they are used as per CPU clockevent device when possible. 865 866# Mark as expert because too many people got it wrong. 867# The code disables itself when not needed. 868config DMI 869 default y 870 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 871 bool "Enable DMI scanning" if EXPERT 872 ---help--- 873 Enabled scanning of DMI to identify machine quirks. Say Y 874 here unless you have verified that your setup is not 875 affected by entries in the DMI blacklist. Required by PNP 876 BIOS code. 877 878config GART_IOMMU 879 bool "Old AMD GART IOMMU support" 880 select SWIOTLB 881 depends on X86_64 && PCI && AMD_NB 882 ---help--- 883 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 884 GART based hardware IOMMUs. 885 886 The GART supports full DMA access for devices with 32-bit access 887 limitations, on systems with more than 3 GB. This is usually needed 888 for USB, sound, many IDE/SATA chipsets and some other devices. 889 890 Newer systems typically have a modern AMD IOMMU, supported via 891 the CONFIG_AMD_IOMMU=y config option. 892 893 In normal configurations this driver is only active when needed: 894 there's more than 3 GB of memory and the system contains a 895 32-bit limited device. 896 897 If unsure, say Y. 898 899config CALGARY_IOMMU 900 bool "IBM Calgary IOMMU support" 901 select SWIOTLB 902 depends on X86_64 && PCI 903 ---help--- 904 Support for hardware IOMMUs in IBM's xSeries x366 and x460 905 systems. Needed to run systems with more than 3GB of memory 906 properly with 32-bit PCI devices that do not support DAC 907 (Double Address Cycle). Calgary also supports bus level 908 isolation, where all DMAs pass through the IOMMU. This 909 prevents them from going anywhere except their intended 910 destination. This catches hard-to-find kernel bugs and 911 mis-behaving drivers and devices that do not use the DMA-API 912 properly to set up their DMA buffers. The IOMMU can be 913 turned off at boot time with the iommu=off parameter. 914 Normally the kernel will make the right choice by itself. 915 If unsure, say Y. 916 917config CALGARY_IOMMU_ENABLED_BY_DEFAULT 918 def_bool y 919 prompt "Should Calgary be enabled by default?" 920 depends on CALGARY_IOMMU 921 ---help--- 922 Should Calgary be enabled by default? if you choose 'y', Calgary 923 will be used (if it exists). If you choose 'n', Calgary will not be 924 used even if it exists. If you choose 'n' and would like to use 925 Calgary anyway, pass 'iommu=calgary' on the kernel command line. 926 If unsure, say Y. 927 928# need this always selected by IOMMU for the VIA workaround 929config SWIOTLB 930 def_bool y if X86_64 931 ---help--- 932 Support for software bounce buffers used on x86-64 systems 933 which don't have a hardware IOMMU. Using this PCI devices 934 which can only access 32-bits of memory can be used on systems 935 with more than 3 GB of memory. 936 If unsure, say Y. 937 938config IOMMU_HELPER 939 def_bool y 940 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU 941 942config MAXSMP 943 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 944 depends on X86_64 && SMP && DEBUG_KERNEL 945 select CPUMASK_OFFSTACK 946 ---help--- 947 Enable maximum number of CPUS and NUMA Nodes for this architecture. 948 If unsure, say N. 949 950config NR_CPUS 951 int "Maximum number of CPUs" if SMP && !MAXSMP 952 range 2 8 if SMP && X86_32 && !X86_BIGSMP 953 range 2 64 if SMP && X86_32 && X86_BIGSMP 954 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK && X86_64 955 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64 956 default "1" if !SMP 957 default "8192" if MAXSMP 958 default "32" if SMP && X86_BIGSMP 959 default "8" if SMP && X86_32 960 default "64" if SMP 961 ---help--- 962 This allows you to specify the maximum number of CPUs which this 963 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 964 supported value is 8192, otherwise the maximum value is 512. The 965 minimum value which makes sense is 2. 966 967 This is purely to save memory - each supported CPU adds 968 approximately eight kilobytes to the kernel image. 969 970config SCHED_SMT 971 bool "SMT (Hyperthreading) scheduler support" 972 depends on SMP 973 ---help--- 974 SMT scheduler support improves the CPU scheduler's decision making 975 when dealing with Intel Pentium 4 chips with HyperThreading at a 976 cost of slightly increased overhead in some places. If unsure say 977 N here. 978 979config SCHED_MC 980 def_bool y 981 prompt "Multi-core scheduler support" 982 depends on SMP 983 ---help--- 984 Multi-core scheduler support improves the CPU scheduler's decision 985 making when dealing with multi-core CPU chips at a cost of slightly 986 increased overhead in some places. If unsure say N here. 987 988config SCHED_MC_PRIO 989 bool "CPU core priorities scheduler support" 990 depends on SCHED_MC && CPU_SUP_INTEL 991 select X86_INTEL_PSTATE 992 select CPU_FREQ 993 default y 994 ---help--- 995 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 996 core ordering determined at manufacturing time, which allows 997 certain cores to reach higher turbo frequencies (when running 998 single threaded workloads) than others. 999 1000 Enabling this kernel feature teaches the scheduler about 1001 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1002 scheduler's CPU selection logic accordingly, so that higher 1003 overall system performance can be achieved. 1004 1005 This feature will have no effect on CPUs without this feature. 1006 1007 If unsure say Y here. 1008 1009source "kernel/Kconfig.preempt" 1010 1011config UP_LATE_INIT 1012 def_bool y 1013 depends on !SMP && X86_LOCAL_APIC 1014 1015config X86_UP_APIC 1016 bool "Local APIC support on uniprocessors" if !PCI_MSI 1017 default PCI_MSI 1018 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1019 ---help--- 1020 A local APIC (Advanced Programmable Interrupt Controller) is an 1021 integrated interrupt controller in the CPU. If you have a single-CPU 1022 system which has a processor with a local APIC, you can say Y here to 1023 enable and use it. If you say Y here even though your machine doesn't 1024 have a local APIC, then the kernel will still run with no slowdown at 1025 all. The local APIC supports CPU-generated self-interrupts (timer, 1026 performance counters), and the NMI watchdog which detects hard 1027 lockups. 1028 1029config X86_UP_IOAPIC 1030 bool "IO-APIC support on uniprocessors" 1031 depends on X86_UP_APIC 1032 ---help--- 1033 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1034 SMP-capable replacement for PC-style interrupt controllers. Most 1035 SMP systems and many recent uniprocessor systems have one. 1036 1037 If you have a single-CPU system with an IO-APIC, you can say Y here 1038 to use it. If you say Y here even though your machine doesn't have 1039 an IO-APIC, then the kernel will still run with no slowdown at all. 1040 1041config X86_LOCAL_APIC 1042 def_bool y 1043 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1044 select IRQ_DOMAIN_HIERARCHY 1045 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1046 1047config X86_IO_APIC 1048 def_bool y 1049 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1050 1051config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1052 bool "Reroute for broken boot IRQs" 1053 depends on X86_IO_APIC 1054 ---help--- 1055 This option enables a workaround that fixes a source of 1056 spurious interrupts. This is recommended when threaded 1057 interrupt handling is used on systems where the generation of 1058 superfluous "boot interrupts" cannot be disabled. 1059 1060 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1061 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1062 kernel does during interrupt handling). On chipsets where this 1063 boot IRQ generation cannot be disabled, this workaround keeps 1064 the original IRQ line masked so that only the equivalent "boot 1065 IRQ" is delivered to the CPUs. The workaround also tells the 1066 kernel to set up the IRQ handler on the boot IRQ line. In this 1067 way only one interrupt is delivered to the kernel. Otherwise 1068 the spurious second interrupt may cause the kernel to bring 1069 down (vital) interrupt lines. 1070 1071 Only affects "broken" chipsets. Interrupt sharing may be 1072 increased on these systems. 1073 1074config X86_MCE 1075 bool "Machine Check / overheating reporting" 1076 select GENERIC_ALLOCATOR 1077 default y 1078 ---help--- 1079 Machine Check support allows the processor to notify the 1080 kernel if it detects a problem (e.g. overheating, data corruption). 1081 The action the kernel takes depends on the severity of the problem, 1082 ranging from warning messages to halting the machine. 1083 1084config X86_MCELOG_LEGACY 1085 bool "Support for deprecated /dev/mcelog character device" 1086 depends on X86_MCE 1087 ---help--- 1088 Enable support for /dev/mcelog which is needed by the old mcelog 1089 userspace logging daemon. Consider switching to the new generation 1090 rasdaemon solution. 1091 1092config X86_MCE_INTEL 1093 def_bool y 1094 prompt "Intel MCE features" 1095 depends on X86_MCE && X86_LOCAL_APIC 1096 ---help--- 1097 Additional support for intel specific MCE features such as 1098 the thermal monitor. 1099 1100config X86_MCE_AMD 1101 def_bool y 1102 prompt "AMD MCE features" 1103 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1104 ---help--- 1105 Additional support for AMD specific MCE features such as 1106 the DRAM Error Threshold. 1107 1108config X86_ANCIENT_MCE 1109 bool "Support for old Pentium 5 / WinChip machine checks" 1110 depends on X86_32 && X86_MCE 1111 ---help--- 1112 Include support for machine check handling on old Pentium 5 or WinChip 1113 systems. These typically need to be enabled explicitly on the command 1114 line. 1115 1116config X86_MCE_THRESHOLD 1117 depends on X86_MCE_AMD || X86_MCE_INTEL 1118 def_bool y 1119 1120config X86_MCE_INJECT 1121 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1122 tristate "Machine check injector support" 1123 ---help--- 1124 Provide support for injecting machine checks for testing purposes. 1125 If you don't know what a machine check is and you don't do kernel 1126 QA it is safe to say n. 1127 1128config X86_THERMAL_VECTOR 1129 def_bool y 1130 depends on X86_MCE_INTEL 1131 1132source "arch/x86/events/Kconfig" 1133 1134config X86_LEGACY_VM86 1135 bool "Legacy VM86 support" 1136 default n 1137 depends on X86_32 1138 ---help--- 1139 This option allows user programs to put the CPU into V8086 1140 mode, which is an 80286-era approximation of 16-bit real mode. 1141 1142 Some very old versions of X and/or vbetool require this option 1143 for user mode setting. Similarly, DOSEMU will use it if 1144 available to accelerate real mode DOS programs. However, any 1145 recent version of DOSEMU, X, or vbetool should be fully 1146 functional even without kernel VM86 support, as they will all 1147 fall back to software emulation. Nevertheless, if you are using 1148 a 16-bit DOS program where 16-bit performance matters, vm86 1149 mode might be faster than emulation and you might want to 1150 enable this option. 1151 1152 Note that any app that works on a 64-bit kernel is unlikely to 1153 need this option, as 64-bit kernels don't, and can't, support 1154 V8086 mode. This option is also unrelated to 16-bit protected 1155 mode and is not needed to run most 16-bit programs under Wine. 1156 1157 Enabling this option increases the complexity of the kernel 1158 and slows down exception handling a tiny bit. 1159 1160 If unsure, say N here. 1161 1162config VM86 1163 bool 1164 default X86_LEGACY_VM86 1165 1166config X86_16BIT 1167 bool "Enable support for 16-bit segments" if EXPERT 1168 default y 1169 depends on MODIFY_LDT_SYSCALL 1170 ---help--- 1171 This option is required by programs like Wine to run 16-bit 1172 protected mode legacy code on x86 processors. Disabling 1173 this option saves about 300 bytes on i386, or around 6K text 1174 plus 16K runtime memory on x86-64, 1175 1176config X86_ESPFIX32 1177 def_bool y 1178 depends on X86_16BIT && X86_32 1179 1180config X86_ESPFIX64 1181 def_bool y 1182 depends on X86_16BIT && X86_64 1183 1184config X86_VSYSCALL_EMULATION 1185 bool "Enable vsyscall emulation" if EXPERT 1186 default y 1187 depends on X86_64 1188 ---help--- 1189 This enables emulation of the legacy vsyscall page. Disabling 1190 it is roughly equivalent to booting with vsyscall=none, except 1191 that it will also disable the helpful warning if a program 1192 tries to use a vsyscall. With this option set to N, offending 1193 programs will just segfault, citing addresses of the form 1194 0xffffffffff600?00. 1195 1196 This option is required by many programs built before 2013, and 1197 care should be used even with newer programs if set to N. 1198 1199 Disabling this option saves about 7K of kernel size and 1200 possibly 4K of additional runtime pagetable memory. 1201 1202config TOSHIBA 1203 tristate "Toshiba Laptop support" 1204 depends on X86_32 1205 ---help--- 1206 This adds a driver to safely access the System Management Mode of 1207 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1208 not work on models with a Phoenix BIOS. The System Management Mode 1209 is used to set the BIOS and power saving options on Toshiba portables. 1210 1211 For information on utilities to make use of this driver see the 1212 Toshiba Linux utilities web site at: 1213 <http://www.buzzard.org.uk/toshiba/>. 1214 1215 Say Y if you intend to run this kernel on a Toshiba portable. 1216 Say N otherwise. 1217 1218config I8K 1219 tristate "Dell i8k legacy laptop support" 1220 select HWMON 1221 select SENSORS_DELL_SMM 1222 ---help--- 1223 This option enables legacy /proc/i8k userspace interface in hwmon 1224 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1225 temperature and allows controlling fan speeds of Dell laptops via 1226 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1227 it reports also power and hotkey status. For fan speed control is 1228 needed userspace package i8kutils. 1229 1230 Say Y if you intend to run this kernel on old Dell laptops or want to 1231 use userspace package i8kutils. 1232 Say N otherwise. 1233 1234config X86_REBOOTFIXUPS 1235 bool "Enable X86 board specific fixups for reboot" 1236 depends on X86_32 1237 ---help--- 1238 This enables chipset and/or board specific fixups to be done 1239 in order to get reboot to work correctly. This is only needed on 1240 some combinations of hardware and BIOS. The symptom, for which 1241 this config is intended, is when reboot ends with a stalled/hung 1242 system. 1243 1244 Currently, the only fixup is for the Geode machines using 1245 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1246 1247 Say Y if you want to enable the fixup. Currently, it's safe to 1248 enable this option even if you don't need it. 1249 Say N otherwise. 1250 1251config MICROCODE 1252 bool "CPU microcode loading support" 1253 default y 1254 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1255 select FW_LOADER 1256 ---help--- 1257 If you say Y here, you will be able to update the microcode on 1258 Intel and AMD processors. The Intel support is for the IA32 family, 1259 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1260 AMD support is for families 0x10 and later. You will obviously need 1261 the actual microcode binary data itself which is not shipped with 1262 the Linux kernel. 1263 1264 The preferred method to load microcode from a detached initrd is described 1265 in Documentation/x86/early-microcode.txt. For that you need to enable 1266 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1267 initrd for microcode blobs. 1268 1269 In addition, you can build the microcode into the kernel. For that you 1270 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1271 config option. 1272 1273config MICROCODE_INTEL 1274 bool "Intel microcode loading support" 1275 depends on MICROCODE 1276 default MICROCODE 1277 select FW_LOADER 1278 ---help--- 1279 This options enables microcode patch loading support for Intel 1280 processors. 1281 1282 For the current Intel microcode data package go to 1283 <https://downloadcenter.intel.com> and search for 1284 'Linux Processor Microcode Data File'. 1285 1286config MICROCODE_AMD 1287 bool "AMD microcode loading support" 1288 depends on MICROCODE 1289 select FW_LOADER 1290 ---help--- 1291 If you select this option, microcode patch loading support for AMD 1292 processors will be enabled. 1293 1294config MICROCODE_OLD_INTERFACE 1295 def_bool y 1296 depends on MICROCODE 1297 1298config X86_MSR 1299 tristate "/dev/cpu/*/msr - Model-specific register support" 1300 ---help--- 1301 This device gives privileged processes access to the x86 1302 Model-Specific Registers (MSRs). It is a character device with 1303 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1304 MSR accesses are directed to a specific CPU on multi-processor 1305 systems. 1306 1307config X86_CPUID 1308 tristate "/dev/cpu/*/cpuid - CPU information support" 1309 ---help--- 1310 This device gives processes access to the x86 CPUID instruction to 1311 be executed on a specific processor. It is a character device 1312 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1313 /dev/cpu/31/cpuid. 1314 1315choice 1316 prompt "High Memory Support" 1317 default HIGHMEM4G 1318 depends on X86_32 1319 1320config NOHIGHMEM 1321 bool "off" 1322 ---help--- 1323 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1324 However, the address space of 32-bit x86 processors is only 4 1325 Gigabytes large. That means that, if you have a large amount of 1326 physical memory, not all of it can be "permanently mapped" by the 1327 kernel. The physical memory that's not permanently mapped is called 1328 "high memory". 1329 1330 If you are compiling a kernel which will never run on a machine with 1331 more than 1 Gigabyte total physical RAM, answer "off" here (default 1332 choice and suitable for most users). This will result in a "3GB/1GB" 1333 split: 3GB are mapped so that each process sees a 3GB virtual memory 1334 space and the remaining part of the 4GB virtual memory space is used 1335 by the kernel to permanently map as much physical memory as 1336 possible. 1337 1338 If the machine has between 1 and 4 Gigabytes physical RAM, then 1339 answer "4GB" here. 1340 1341 If more than 4 Gigabytes is used then answer "64GB" here. This 1342 selection turns Intel PAE (Physical Address Extension) mode on. 1343 PAE implements 3-level paging on IA32 processors. PAE is fully 1344 supported by Linux, PAE mode is implemented on all recent Intel 1345 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1346 then the kernel will not boot on CPUs that don't support PAE! 1347 1348 The actual amount of total physical memory will either be 1349 auto detected or can be forced by using a kernel command line option 1350 such as "mem=256M". (Try "man bootparam" or see the documentation of 1351 your boot loader (lilo or loadlin) about how to pass options to the 1352 kernel at boot time.) 1353 1354 If unsure, say "off". 1355 1356config HIGHMEM4G 1357 bool "4GB" 1358 ---help--- 1359 Select this if you have a 32-bit processor and between 1 and 4 1360 gigabytes of physical RAM. 1361 1362config HIGHMEM64G 1363 bool "64GB" 1364 depends on !M486 1365 select X86_PAE 1366 ---help--- 1367 Select this if you have a 32-bit processor and more than 4 1368 gigabytes of physical RAM. 1369 1370endchoice 1371 1372choice 1373 prompt "Memory split" if EXPERT 1374 default VMSPLIT_3G 1375 depends on X86_32 1376 ---help--- 1377 Select the desired split between kernel and user memory. 1378 1379 If the address range available to the kernel is less than the 1380 physical memory installed, the remaining memory will be available 1381 as "high memory". Accessing high memory is a little more costly 1382 than low memory, as it needs to be mapped into the kernel first. 1383 Note that increasing the kernel address space limits the range 1384 available to user programs, making the address space there 1385 tighter. Selecting anything other than the default 3G/1G split 1386 will also likely make your kernel incompatible with binary-only 1387 kernel modules. 1388 1389 If you are not absolutely sure what you are doing, leave this 1390 option alone! 1391 1392 config VMSPLIT_3G 1393 bool "3G/1G user/kernel split" 1394 config VMSPLIT_3G_OPT 1395 depends on !X86_PAE 1396 bool "3G/1G user/kernel split (for full 1G low memory)" 1397 config VMSPLIT_2G 1398 bool "2G/2G user/kernel split" 1399 config VMSPLIT_2G_OPT 1400 depends on !X86_PAE 1401 bool "2G/2G user/kernel split (for full 2G low memory)" 1402 config VMSPLIT_1G 1403 bool "1G/3G user/kernel split" 1404endchoice 1405 1406config PAGE_OFFSET 1407 hex 1408 default 0xB0000000 if VMSPLIT_3G_OPT 1409 default 0x80000000 if VMSPLIT_2G 1410 default 0x78000000 if VMSPLIT_2G_OPT 1411 default 0x40000000 if VMSPLIT_1G 1412 default 0xC0000000 1413 depends on X86_32 1414 1415config HIGHMEM 1416 def_bool y 1417 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1418 1419config X86_PAE 1420 bool "PAE (Physical Address Extension) Support" 1421 depends on X86_32 && !HIGHMEM4G 1422 select SWIOTLB 1423 ---help--- 1424 PAE is required for NX support, and furthermore enables 1425 larger swapspace support for non-overcommit purposes. It 1426 has the cost of more pagetable lookup overhead, and also 1427 consumes more pagetable space per process. 1428 1429config X86_5LEVEL 1430 bool "Enable 5-level page tables support" 1431 depends on X86_64 1432 ---help--- 1433 5-level paging enables access to larger address space: 1434 upto 128 PiB of virtual address space and 4 PiB of 1435 physical address space. 1436 1437 It will be supported by future Intel CPUs. 1438 1439 Note: a kernel with this option enabled can only be booted 1440 on machines that support the feature. 1441 1442 See Documentation/x86/x86_64/5level-paging.txt for more 1443 information. 1444 1445 Say N if unsure. 1446 1447config ARCH_PHYS_ADDR_T_64BIT 1448 def_bool y 1449 depends on X86_64 || X86_PAE 1450 1451config ARCH_DMA_ADDR_T_64BIT 1452 def_bool y 1453 depends on X86_64 || HIGHMEM64G 1454 1455config X86_DIRECT_GBPAGES 1456 def_bool y 1457 depends on X86_64 && !DEBUG_PAGEALLOC 1458 ---help--- 1459 Certain kernel features effectively disable kernel 1460 linear 1 GB mappings (even if the CPU otherwise 1461 supports them), so don't confuse the user by printing 1462 that we have them enabled. 1463 1464config ARCH_HAS_MEM_ENCRYPT 1465 def_bool y 1466 1467config AMD_MEM_ENCRYPT 1468 bool "AMD Secure Memory Encryption (SME) support" 1469 depends on X86_64 && CPU_SUP_AMD 1470 ---help--- 1471 Say yes to enable support for the encryption of system memory. 1472 This requires an AMD processor that supports Secure Memory 1473 Encryption (SME). 1474 1475config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1476 bool "Activate AMD Secure Memory Encryption (SME) by default" 1477 default y 1478 depends on AMD_MEM_ENCRYPT 1479 ---help--- 1480 Say yes to have system memory encrypted by default if running on 1481 an AMD processor that supports Secure Memory Encryption (SME). 1482 1483 If set to Y, then the encryption of system memory can be 1484 deactivated with the mem_encrypt=off command line option. 1485 1486 If set to N, then the encryption of system memory can be 1487 activated with the mem_encrypt=on command line option. 1488 1489config ARCH_USE_MEMREMAP_PROT 1490 def_bool y 1491 depends on AMD_MEM_ENCRYPT 1492 1493# Common NUMA Features 1494config NUMA 1495 bool "Numa Memory Allocation and Scheduler Support" 1496 depends on SMP 1497 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1498 default y if X86_BIGSMP 1499 ---help--- 1500 Enable NUMA (Non Uniform Memory Access) support. 1501 1502 The kernel will try to allocate memory used by a CPU on the 1503 local memory controller of the CPU and add some more 1504 NUMA awareness to the kernel. 1505 1506 For 64-bit this is recommended if the system is Intel Core i7 1507 (or later), AMD Opteron, or EM64T NUMA. 1508 1509 For 32-bit this is only needed if you boot a 32-bit 1510 kernel on a 64-bit NUMA platform. 1511 1512 Otherwise, you should say N. 1513 1514config AMD_NUMA 1515 def_bool y 1516 prompt "Old style AMD Opteron NUMA detection" 1517 depends on X86_64 && NUMA && PCI 1518 ---help--- 1519 Enable AMD NUMA node topology detection. You should say Y here if 1520 you have a multi processor AMD system. This uses an old method to 1521 read the NUMA configuration directly from the builtin Northbridge 1522 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1523 which also takes priority if both are compiled in. 1524 1525config X86_64_ACPI_NUMA 1526 def_bool y 1527 prompt "ACPI NUMA detection" 1528 depends on X86_64 && NUMA && ACPI && PCI 1529 select ACPI_NUMA 1530 ---help--- 1531 Enable ACPI SRAT based node topology detection. 1532 1533# Some NUMA nodes have memory ranges that span 1534# other nodes. Even though a pfn is valid and 1535# between a node's start and end pfns, it may not 1536# reside on that node. See memmap_init_zone() 1537# for details. 1538config NODES_SPAN_OTHER_NODES 1539 def_bool y 1540 depends on X86_64_ACPI_NUMA 1541 1542config NUMA_EMU 1543 bool "NUMA emulation" 1544 depends on NUMA 1545 ---help--- 1546 Enable NUMA emulation. A flat machine will be split 1547 into virtual nodes when booted with "numa=fake=N", where N is the 1548 number of nodes. This is only useful for debugging. 1549 1550config NODES_SHIFT 1551 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1552 range 1 10 1553 default "10" if MAXSMP 1554 default "6" if X86_64 1555 default "3" 1556 depends on NEED_MULTIPLE_NODES 1557 ---help--- 1558 Specify the maximum number of NUMA Nodes available on the target 1559 system. Increases memory reserved to accommodate various tables. 1560 1561config ARCH_HAVE_MEMORY_PRESENT 1562 def_bool y 1563 depends on X86_32 && DISCONTIGMEM 1564 1565config NEED_NODE_MEMMAP_SIZE 1566 def_bool y 1567 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM) 1568 1569config ARCH_FLATMEM_ENABLE 1570 def_bool y 1571 depends on X86_32 && !NUMA 1572 1573config ARCH_DISCONTIGMEM_ENABLE 1574 def_bool y 1575 depends on NUMA && X86_32 1576 1577config ARCH_DISCONTIGMEM_DEFAULT 1578 def_bool y 1579 depends on NUMA && X86_32 1580 1581config ARCH_SPARSEMEM_ENABLE 1582 def_bool y 1583 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1584 select SPARSEMEM_STATIC if X86_32 1585 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1586 1587config ARCH_SPARSEMEM_DEFAULT 1588 def_bool y 1589 depends on X86_64 1590 1591config ARCH_SELECT_MEMORY_MODEL 1592 def_bool y 1593 depends on ARCH_SPARSEMEM_ENABLE 1594 1595config ARCH_MEMORY_PROBE 1596 bool "Enable sysfs memory/probe interface" 1597 depends on X86_64 && MEMORY_HOTPLUG 1598 help 1599 This option enables a sysfs memory/probe interface for testing. 1600 See Documentation/memory-hotplug.txt for more information. 1601 If you are unsure how to answer this question, answer N. 1602 1603config ARCH_PROC_KCORE_TEXT 1604 def_bool y 1605 depends on X86_64 && PROC_KCORE 1606 1607config ILLEGAL_POINTER_VALUE 1608 hex 1609 default 0 if X86_32 1610 default 0xdead000000000000 if X86_64 1611 1612source "mm/Kconfig" 1613 1614config X86_PMEM_LEGACY_DEVICE 1615 bool 1616 1617config X86_PMEM_LEGACY 1618 tristate "Support non-standard NVDIMMs and ADR protected memory" 1619 depends on PHYS_ADDR_T_64BIT 1620 depends on BLK_DEV 1621 select X86_PMEM_LEGACY_DEVICE 1622 select LIBNVDIMM 1623 help 1624 Treat memory marked using the non-standard e820 type of 12 as used 1625 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1626 The kernel will offer these regions to the 'pmem' driver so 1627 they can be used for persistent storage. 1628 1629 Say Y if unsure. 1630 1631config HIGHPTE 1632 bool "Allocate 3rd-level pagetables from highmem" 1633 depends on HIGHMEM 1634 ---help--- 1635 The VM uses one page table entry for each page of physical memory. 1636 For systems with a lot of RAM, this can be wasteful of precious 1637 low memory. Setting this option will put user-space page table 1638 entries in high memory. 1639 1640config X86_CHECK_BIOS_CORRUPTION 1641 bool "Check for low memory corruption" 1642 ---help--- 1643 Periodically check for memory corruption in low memory, which 1644 is suspected to be caused by BIOS. Even when enabled in the 1645 configuration, it is disabled at runtime. Enable it by 1646 setting "memory_corruption_check=1" on the kernel command 1647 line. By default it scans the low 64k of memory every 60 1648 seconds; see the memory_corruption_check_size and 1649 memory_corruption_check_period parameters in 1650 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1651 1652 When enabled with the default parameters, this option has 1653 almost no overhead, as it reserves a relatively small amount 1654 of memory and scans it infrequently. It both detects corruption 1655 and prevents it from affecting the running system. 1656 1657 It is, however, intended as a diagnostic tool; if repeatable 1658 BIOS-originated corruption always affects the same memory, 1659 you can use memmap= to prevent the kernel from using that 1660 memory. 1661 1662config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1663 bool "Set the default setting of memory_corruption_check" 1664 depends on X86_CHECK_BIOS_CORRUPTION 1665 default y 1666 ---help--- 1667 Set whether the default state of memory_corruption_check is 1668 on or off. 1669 1670config X86_RESERVE_LOW 1671 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1672 default 64 1673 range 4 640 1674 ---help--- 1675 Specify the amount of low memory to reserve for the BIOS. 1676 1677 The first page contains BIOS data structures that the kernel 1678 must not use, so that page must always be reserved. 1679 1680 By default we reserve the first 64K of physical RAM, as a 1681 number of BIOSes are known to corrupt that memory range 1682 during events such as suspend/resume or monitor cable 1683 insertion, so it must not be used by the kernel. 1684 1685 You can set this to 4 if you are absolutely sure that you 1686 trust the BIOS to get all its memory reservations and usages 1687 right. If you know your BIOS have problems beyond the 1688 default 64K area, you can set this to 640 to avoid using the 1689 entire low memory range. 1690 1691 If you have doubts about the BIOS (e.g. suspend/resume does 1692 not work or there's kernel crashes after certain hardware 1693 hotplug events) then you might want to enable 1694 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1695 typical corruption patterns. 1696 1697 Leave this to the default value of 64 if you are unsure. 1698 1699config MATH_EMULATION 1700 bool 1701 depends on MODIFY_LDT_SYSCALL 1702 prompt "Math emulation" if X86_32 1703 ---help--- 1704 Linux can emulate a math coprocessor (used for floating point 1705 operations) if you don't have one. 486DX and Pentium processors have 1706 a math coprocessor built in, 486SX and 386 do not, unless you added 1707 a 487DX or 387, respectively. (The messages during boot time can 1708 give you some hints here ["man dmesg"].) Everyone needs either a 1709 coprocessor or this emulation. 1710 1711 If you don't have a math coprocessor, you need to say Y here; if you 1712 say Y here even though you have a coprocessor, the coprocessor will 1713 be used nevertheless. (This behavior can be changed with the kernel 1714 command line option "no387", which comes handy if your coprocessor 1715 is broken. Try "man bootparam" or see the documentation of your boot 1716 loader (lilo or loadlin) about how to pass options to the kernel at 1717 boot time.) This means that it is a good idea to say Y here if you 1718 intend to use this kernel on different machines. 1719 1720 More information about the internals of the Linux math coprocessor 1721 emulation can be found in <file:arch/x86/math-emu/README>. 1722 1723 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1724 kernel, it won't hurt. 1725 1726config MTRR 1727 def_bool y 1728 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1729 ---help--- 1730 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1731 the Memory Type Range Registers (MTRRs) may be used to control 1732 processor access to memory ranges. This is most useful if you have 1733 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1734 allows bus write transfers to be combined into a larger transfer 1735 before bursting over the PCI/AGP bus. This can increase performance 1736 of image write operations 2.5 times or more. Saying Y here creates a 1737 /proc/mtrr file which may be used to manipulate your processor's 1738 MTRRs. Typically the X server should use this. 1739 1740 This code has a reasonably generic interface so that similar 1741 control registers on other processors can be easily supported 1742 as well: 1743 1744 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1745 Registers (ARRs) which provide a similar functionality to MTRRs. For 1746 these, the ARRs are used to emulate the MTRRs. 1747 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1748 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1749 write-combining. All of these processors are supported by this code 1750 and it makes sense to say Y here if you have one of them. 1751 1752 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1753 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1754 can lead to all sorts of problems, so it's good to say Y here. 1755 1756 You can safely say Y even if your machine doesn't have MTRRs, you'll 1757 just add about 9 KB to your kernel. 1758 1759 See <file:Documentation/x86/mtrr.txt> for more information. 1760 1761config MTRR_SANITIZER 1762 def_bool y 1763 prompt "MTRR cleanup support" 1764 depends on MTRR 1765 ---help--- 1766 Convert MTRR layout from continuous to discrete, so X drivers can 1767 add writeback entries. 1768 1769 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1770 The largest mtrr entry size for a continuous block can be set with 1771 mtrr_chunk_size. 1772 1773 If unsure, say Y. 1774 1775config MTRR_SANITIZER_ENABLE_DEFAULT 1776 int "MTRR cleanup enable value (0-1)" 1777 range 0 1 1778 default "0" 1779 depends on MTRR_SANITIZER 1780 ---help--- 1781 Enable mtrr cleanup default value 1782 1783config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1784 int "MTRR cleanup spare reg num (0-7)" 1785 range 0 7 1786 default "1" 1787 depends on MTRR_SANITIZER 1788 ---help--- 1789 mtrr cleanup spare entries default, it can be changed via 1790 mtrr_spare_reg_nr=N on the kernel command line. 1791 1792config X86_PAT 1793 def_bool y 1794 prompt "x86 PAT support" if EXPERT 1795 depends on MTRR 1796 ---help--- 1797 Use PAT attributes to setup page level cache control. 1798 1799 PATs are the modern equivalents of MTRRs and are much more 1800 flexible than MTRRs. 1801 1802 Say N here if you see bootup problems (boot crash, boot hang, 1803 spontaneous reboots) or a non-working video driver. 1804 1805 If unsure, say Y. 1806 1807config ARCH_USES_PG_UNCACHED 1808 def_bool y 1809 depends on X86_PAT 1810 1811config ARCH_RANDOM 1812 def_bool y 1813 prompt "x86 architectural random number generator" if EXPERT 1814 ---help--- 1815 Enable the x86 architectural RDRAND instruction 1816 (Intel Bull Mountain technology) to generate random numbers. 1817 If supported, this is a high bandwidth, cryptographically 1818 secure hardware random number generator. 1819 1820config X86_SMAP 1821 def_bool y 1822 prompt "Supervisor Mode Access Prevention" if EXPERT 1823 ---help--- 1824 Supervisor Mode Access Prevention (SMAP) is a security 1825 feature in newer Intel processors. There is a small 1826 performance cost if this enabled and turned on; there is 1827 also a small increase in the kernel size if this is enabled. 1828 1829 If unsure, say Y. 1830 1831config X86_INTEL_UMIP 1832 def_bool y 1833 depends on CPU_SUP_INTEL 1834 prompt "Intel User Mode Instruction Prevention" if EXPERT 1835 ---help--- 1836 The User Mode Instruction Prevention (UMIP) is a security 1837 feature in newer Intel processors. If enabled, a general 1838 protection fault is issued if the SGDT, SLDT, SIDT, SMSW 1839 or STR instructions are executed in user mode. These instructions 1840 unnecessarily expose information about the hardware state. 1841 1842 The vast majority of applications do not use these instructions. 1843 For the very few that do, software emulation is provided in 1844 specific cases in protected and virtual-8086 modes. Emulated 1845 results are dummy. 1846 1847config X86_INTEL_MPX 1848 prompt "Intel MPX (Memory Protection Extensions)" 1849 def_bool n 1850 # Note: only available in 64-bit mode due to VMA flags shortage 1851 depends on CPU_SUP_INTEL && X86_64 1852 select ARCH_USES_HIGH_VMA_FLAGS 1853 ---help--- 1854 MPX provides hardware features that can be used in 1855 conjunction with compiler-instrumented code to check 1856 memory references. It is designed to detect buffer 1857 overflow or underflow bugs. 1858 1859 This option enables running applications which are 1860 instrumented or otherwise use MPX. It does not use MPX 1861 itself inside the kernel or to protect the kernel 1862 against bad memory references. 1863 1864 Enabling this option will make the kernel larger: 1865 ~8k of kernel text and 36 bytes of data on a 64-bit 1866 defconfig. It adds a long to the 'mm_struct' which 1867 will increase the kernel memory overhead of each 1868 process and adds some branches to paths used during 1869 exec() and munmap(). 1870 1871 For details, see Documentation/x86/intel_mpx.txt 1872 1873 If unsure, say N. 1874 1875config X86_INTEL_MEMORY_PROTECTION_KEYS 1876 prompt "Intel Memory Protection Keys" 1877 def_bool y 1878 # Note: only available in 64-bit mode 1879 depends on CPU_SUP_INTEL && X86_64 1880 select ARCH_USES_HIGH_VMA_FLAGS 1881 select ARCH_HAS_PKEYS 1882 ---help--- 1883 Memory Protection Keys provides a mechanism for enforcing 1884 page-based protections, but without requiring modification of the 1885 page tables when an application changes protection domains. 1886 1887 For details, see Documentation/x86/protection-keys.txt 1888 1889 If unsure, say y. 1890 1891config EFI 1892 bool "EFI runtime service support" 1893 depends on ACPI 1894 select UCS2_STRING 1895 select EFI_RUNTIME_WRAPPERS 1896 ---help--- 1897 This enables the kernel to use EFI runtime services that are 1898 available (such as the EFI variable services). 1899 1900 This option is only useful on systems that have EFI firmware. 1901 In addition, you should use the latest ELILO loader available 1902 at <http://elilo.sourceforge.net> in order to take advantage 1903 of EFI runtime services. However, even with this option, the 1904 resultant kernel should continue to boot on existing non-EFI 1905 platforms. 1906 1907config EFI_STUB 1908 bool "EFI stub support" 1909 depends on EFI && !X86_USE_3DNOW 1910 select RELOCATABLE 1911 ---help--- 1912 This kernel feature allows a bzImage to be loaded directly 1913 by EFI firmware without the use of a bootloader. 1914 1915 See Documentation/efi-stub.txt for more information. 1916 1917config EFI_MIXED 1918 bool "EFI mixed-mode support" 1919 depends on EFI_STUB && X86_64 1920 ---help--- 1921 Enabling this feature allows a 64-bit kernel to be booted 1922 on a 32-bit firmware, provided that your CPU supports 64-bit 1923 mode. 1924 1925 Note that it is not possible to boot a mixed-mode enabled 1926 kernel via the EFI boot stub - a bootloader that supports 1927 the EFI handover protocol must be used. 1928 1929 If unsure, say N. 1930 1931config SECCOMP 1932 def_bool y 1933 prompt "Enable seccomp to safely compute untrusted bytecode" 1934 ---help--- 1935 This kernel feature is useful for number crunching applications 1936 that may need to compute untrusted bytecode during their 1937 execution. By using pipes or other transports made available to 1938 the process as file descriptors supporting the read/write 1939 syscalls, it's possible to isolate those applications in 1940 their own address space using seccomp. Once seccomp is 1941 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 1942 and the task is only allowed to execute a few safe syscalls 1943 defined by each seccomp mode. 1944 1945 If unsure, say Y. Only embedded should say N here. 1946 1947source kernel/Kconfig.hz 1948 1949config KEXEC 1950 bool "kexec system call" 1951 select KEXEC_CORE 1952 ---help--- 1953 kexec is a system call that implements the ability to shutdown your 1954 current kernel, and to start another kernel. It is like a reboot 1955 but it is independent of the system firmware. And like a reboot 1956 you can start any kernel with it, not just Linux. 1957 1958 The name comes from the similarity to the exec system call. 1959 1960 It is an ongoing process to be certain the hardware in a machine 1961 is properly shutdown, so do not be surprised if this code does not 1962 initially work for you. As of this writing the exact hardware 1963 interface is strongly in flux, so no good recommendation can be 1964 made. 1965 1966config KEXEC_FILE 1967 bool "kexec file based system call" 1968 select KEXEC_CORE 1969 select BUILD_BIN2C 1970 depends on X86_64 1971 depends on CRYPTO=y 1972 depends on CRYPTO_SHA256=y 1973 ---help--- 1974 This is new version of kexec system call. This system call is 1975 file based and takes file descriptors as system call argument 1976 for kernel and initramfs as opposed to list of segments as 1977 accepted by previous system call. 1978 1979config KEXEC_VERIFY_SIG 1980 bool "Verify kernel signature during kexec_file_load() syscall" 1981 depends on KEXEC_FILE 1982 ---help--- 1983 This option makes kernel signature verification mandatory for 1984 the kexec_file_load() syscall. 1985 1986 In addition to that option, you need to enable signature 1987 verification for the corresponding kernel image type being 1988 loaded in order for this to work. 1989 1990config KEXEC_BZIMAGE_VERIFY_SIG 1991 bool "Enable bzImage signature verification support" 1992 depends on KEXEC_VERIFY_SIG 1993 depends on SIGNED_PE_FILE_VERIFICATION 1994 select SYSTEM_TRUSTED_KEYRING 1995 ---help--- 1996 Enable bzImage signature verification support. 1997 1998config CRASH_DUMP 1999 bool "kernel crash dumps" 2000 depends on X86_64 || (X86_32 && HIGHMEM) 2001 ---help--- 2002 Generate crash dump after being started by kexec. 2003 This should be normally only set in special crash dump kernels 2004 which are loaded in the main kernel with kexec-tools into 2005 a specially reserved region and then later executed after 2006 a crash by kdump/kexec. The crash dump kernel must be compiled 2007 to a memory address not used by the main kernel or BIOS using 2008 PHYSICAL_START, or it must be built as a relocatable image 2009 (CONFIG_RELOCATABLE=y). 2010 For more details see Documentation/kdump/kdump.txt 2011 2012config KEXEC_JUMP 2013 bool "kexec jump" 2014 depends on KEXEC && HIBERNATION 2015 ---help--- 2016 Jump between original kernel and kexeced kernel and invoke 2017 code in physical address mode via KEXEC 2018 2019config PHYSICAL_START 2020 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2021 default "0x1000000" 2022 ---help--- 2023 This gives the physical address where the kernel is loaded. 2024 2025 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2026 bzImage will decompress itself to above physical address and 2027 run from there. Otherwise, bzImage will run from the address where 2028 it has been loaded by the boot loader and will ignore above physical 2029 address. 2030 2031 In normal kdump cases one does not have to set/change this option 2032 as now bzImage can be compiled as a completely relocatable image 2033 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2034 address. This option is mainly useful for the folks who don't want 2035 to use a bzImage for capturing the crash dump and want to use a 2036 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2037 to be specifically compiled to run from a specific memory area 2038 (normally a reserved region) and this option comes handy. 2039 2040 So if you are using bzImage for capturing the crash dump, 2041 leave the value here unchanged to 0x1000000 and set 2042 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2043 for capturing the crash dump change this value to start of 2044 the reserved region. In other words, it can be set based on 2045 the "X" value as specified in the "crashkernel=YM@XM" 2046 command line boot parameter passed to the panic-ed 2047 kernel. Please take a look at Documentation/kdump/kdump.txt 2048 for more details about crash dumps. 2049 2050 Usage of bzImage for capturing the crash dump is recommended as 2051 one does not have to build two kernels. Same kernel can be used 2052 as production kernel and capture kernel. Above option should have 2053 gone away after relocatable bzImage support is introduced. But it 2054 is present because there are users out there who continue to use 2055 vmlinux for dump capture. This option should go away down the 2056 line. 2057 2058 Don't change this unless you know what you are doing. 2059 2060config RELOCATABLE 2061 bool "Build a relocatable kernel" 2062 default y 2063 ---help--- 2064 This builds a kernel image that retains relocation information 2065 so it can be loaded someplace besides the default 1MB. 2066 The relocations tend to make the kernel binary about 10% larger, 2067 but are discarded at runtime. 2068 2069 One use is for the kexec on panic case where the recovery kernel 2070 must live at a different physical address than the primary 2071 kernel. 2072 2073 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2074 it has been loaded at and the compile time physical address 2075 (CONFIG_PHYSICAL_START) is used as the minimum location. 2076 2077config RANDOMIZE_BASE 2078 bool "Randomize the address of the kernel image (KASLR)" 2079 depends on RELOCATABLE 2080 default y 2081 ---help--- 2082 In support of Kernel Address Space Layout Randomization (KASLR), 2083 this randomizes the physical address at which the kernel image 2084 is decompressed and the virtual address where the kernel 2085 image is mapped, as a security feature that deters exploit 2086 attempts relying on knowledge of the location of kernel 2087 code internals. 2088 2089 On 64-bit, the kernel physical and virtual addresses are 2090 randomized separately. The physical address will be anywhere 2091 between 16MB and the top of physical memory (up to 64TB). The 2092 virtual address will be randomized from 16MB up to 1GB (9 bits 2093 of entropy). Note that this also reduces the memory space 2094 available to kernel modules from 1.5GB to 1GB. 2095 2096 On 32-bit, the kernel physical and virtual addresses are 2097 randomized together. They will be randomized from 16MB up to 2098 512MB (8 bits of entropy). 2099 2100 Entropy is generated using the RDRAND instruction if it is 2101 supported. If RDTSC is supported, its value is mixed into 2102 the entropy pool as well. If neither RDRAND nor RDTSC are 2103 supported, then entropy is read from the i8254 timer. The 2104 usable entropy is limited by the kernel being built using 2105 2GB addressing, and that PHYSICAL_ALIGN must be at a 2106 minimum of 2MB. As a result, only 10 bits of entropy are 2107 theoretically possible, but the implementations are further 2108 limited due to memory layouts. 2109 2110 If unsure, say Y. 2111 2112# Relocation on x86 needs some additional build support 2113config X86_NEED_RELOCS 2114 def_bool y 2115 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2116 2117config PHYSICAL_ALIGN 2118 hex "Alignment value to which kernel should be aligned" 2119 default "0x200000" 2120 range 0x2000 0x1000000 if X86_32 2121 range 0x200000 0x1000000 if X86_64 2122 ---help--- 2123 This value puts the alignment restrictions on physical address 2124 where kernel is loaded and run from. Kernel is compiled for an 2125 address which meets above alignment restriction. 2126 2127 If bootloader loads the kernel at a non-aligned address and 2128 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2129 address aligned to above value and run from there. 2130 2131 If bootloader loads the kernel at a non-aligned address and 2132 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2133 load address and decompress itself to the address it has been 2134 compiled for and run from there. The address for which kernel is 2135 compiled already meets above alignment restrictions. Hence the 2136 end result is that kernel runs from a physical address meeting 2137 above alignment restrictions. 2138 2139 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2140 this value must be a multiple of 0x200000. 2141 2142 Don't change this unless you know what you are doing. 2143 2144config RANDOMIZE_MEMORY 2145 bool "Randomize the kernel memory sections" 2146 depends on X86_64 2147 depends on RANDOMIZE_BASE 2148 default RANDOMIZE_BASE 2149 ---help--- 2150 Randomizes the base virtual address of kernel memory sections 2151 (physical memory mapping, vmalloc & vmemmap). This security feature 2152 makes exploits relying on predictable memory locations less reliable. 2153 2154 The order of allocations remains unchanged. Entropy is generated in 2155 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2156 configuration have in average 30,000 different possible virtual 2157 addresses for each memory section. 2158 2159 If unsure, say Y. 2160 2161config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2162 hex "Physical memory mapping padding" if EXPERT 2163 depends on RANDOMIZE_MEMORY 2164 default "0xa" if MEMORY_HOTPLUG 2165 default "0x0" 2166 range 0x1 0x40 if MEMORY_HOTPLUG 2167 range 0x0 0x40 2168 ---help--- 2169 Define the padding in terabytes added to the existing physical 2170 memory size during kernel memory randomization. It is useful 2171 for memory hotplug support but reduces the entropy available for 2172 address randomization. 2173 2174 If unsure, leave at the default value. 2175 2176config HOTPLUG_CPU 2177 bool "Support for hot-pluggable CPUs" 2178 depends on SMP 2179 ---help--- 2180 Say Y here to allow turning CPUs off and on. CPUs can be 2181 controlled through /sys/devices/system/cpu. 2182 ( Note: power management support will enable this option 2183 automatically on SMP systems. ) 2184 Say N if you want to disable CPU hotplug. 2185 2186config BOOTPARAM_HOTPLUG_CPU0 2187 bool "Set default setting of cpu0_hotpluggable" 2188 default n 2189 depends on HOTPLUG_CPU 2190 ---help--- 2191 Set whether default state of cpu0_hotpluggable is on or off. 2192 2193 Say Y here to enable CPU0 hotplug by default. If this switch 2194 is turned on, there is no need to give cpu0_hotplug kernel 2195 parameter and the CPU0 hotplug feature is enabled by default. 2196 2197 Please note: there are two known CPU0 dependencies if you want 2198 to enable the CPU0 hotplug feature either by this switch or by 2199 cpu0_hotplug kernel parameter. 2200 2201 First, resume from hibernate or suspend always starts from CPU0. 2202 So hibernate and suspend are prevented if CPU0 is offline. 2203 2204 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2205 offline if any interrupt can not migrate out of CPU0. There may 2206 be other CPU0 dependencies. 2207 2208 Please make sure the dependencies are under your control before 2209 you enable this feature. 2210 2211 Say N if you don't want to enable CPU0 hotplug feature by default. 2212 You still can enable the CPU0 hotplug feature at boot by kernel 2213 parameter cpu0_hotplug. 2214 2215config DEBUG_HOTPLUG_CPU0 2216 def_bool n 2217 prompt "Debug CPU0 hotplug" 2218 depends on HOTPLUG_CPU 2219 ---help--- 2220 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2221 soon as possible and boots up userspace with CPU0 offlined. User 2222 can online CPU0 back after boot time. 2223 2224 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2225 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2226 compilation or giving cpu0_hotplug kernel parameter at boot. 2227 2228 If unsure, say N. 2229 2230config COMPAT_VDSO 2231 def_bool n 2232 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2233 depends on COMPAT_32 2234 ---help--- 2235 Certain buggy versions of glibc will crash if they are 2236 presented with a 32-bit vDSO that is not mapped at the address 2237 indicated in its segment table. 2238 2239 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2240 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2241 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2242 the only released version with the bug, but OpenSUSE 9 2243 contains a buggy "glibc 2.3.2". 2244 2245 The symptom of the bug is that everything crashes on startup, saying: 2246 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2247 2248 Saying Y here changes the default value of the vdso32 boot 2249 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2250 This works around the glibc bug but hurts performance. 2251 2252 If unsure, say N: if you are compiling your own kernel, you 2253 are unlikely to be using a buggy version of glibc. 2254 2255choice 2256 prompt "vsyscall table for legacy applications" 2257 depends on X86_64 2258 default LEGACY_VSYSCALL_EMULATE 2259 help 2260 Legacy user code that does not know how to find the vDSO expects 2261 to be able to issue three syscalls by calling fixed addresses in 2262 kernel space. Since this location is not randomized with ASLR, 2263 it can be used to assist security vulnerability exploitation. 2264 2265 This setting can be changed at boot time via the kernel command 2266 line parameter vsyscall=[native|emulate|none]. 2267 2268 On a system with recent enough glibc (2.14 or newer) and no 2269 static binaries, you can say None without a performance penalty 2270 to improve security. 2271 2272 If unsure, select "Emulate". 2273 2274 config LEGACY_VSYSCALL_NATIVE 2275 bool "Native" 2276 help 2277 Actual executable code is located in the fixed vsyscall 2278 address mapping, implementing time() efficiently. Since 2279 this makes the mapping executable, it can be used during 2280 security vulnerability exploitation (traditionally as 2281 ROP gadgets). This configuration is not recommended. 2282 2283 config LEGACY_VSYSCALL_EMULATE 2284 bool "Emulate" 2285 help 2286 The kernel traps and emulates calls into the fixed 2287 vsyscall address mapping. This makes the mapping 2288 non-executable, but it still contains known contents, 2289 which could be used in certain rare security vulnerability 2290 exploits. This configuration is recommended when userspace 2291 still uses the vsyscall area. 2292 2293 config LEGACY_VSYSCALL_NONE 2294 bool "None" 2295 help 2296 There will be no vsyscall mapping at all. This will 2297 eliminate any risk of ASLR bypass due to the vsyscall 2298 fixed address mapping. Attempts to use the vsyscalls 2299 will be reported to dmesg, so that either old or 2300 malicious userspace programs can be identified. 2301 2302endchoice 2303 2304config CMDLINE_BOOL 2305 bool "Built-in kernel command line" 2306 ---help--- 2307 Allow for specifying boot arguments to the kernel at 2308 build time. On some systems (e.g. embedded ones), it is 2309 necessary or convenient to provide some or all of the 2310 kernel boot arguments with the kernel itself (that is, 2311 to not rely on the boot loader to provide them.) 2312 2313 To compile command line arguments into the kernel, 2314 set this option to 'Y', then fill in the 2315 boot arguments in CONFIG_CMDLINE. 2316 2317 Systems with fully functional boot loaders (i.e. non-embedded) 2318 should leave this option set to 'N'. 2319 2320config CMDLINE 2321 string "Built-in kernel command string" 2322 depends on CMDLINE_BOOL 2323 default "" 2324 ---help--- 2325 Enter arguments here that should be compiled into the kernel 2326 image and used at boot time. If the boot loader provides a 2327 command line at boot time, it is appended to this string to 2328 form the full kernel command line, when the system boots. 2329 2330 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2331 change this behavior. 2332 2333 In most cases, the command line (whether built-in or provided 2334 by the boot loader) should specify the device for the root 2335 file system. 2336 2337config CMDLINE_OVERRIDE 2338 bool "Built-in command line overrides boot loader arguments" 2339 depends on CMDLINE_BOOL 2340 ---help--- 2341 Set this option to 'Y' to have the kernel ignore the boot loader 2342 command line, and use ONLY the built-in command line. 2343 2344 This is used to work around broken boot loaders. This should 2345 be set to 'N' under normal conditions. 2346 2347config MODIFY_LDT_SYSCALL 2348 bool "Enable the LDT (local descriptor table)" if EXPERT 2349 default y 2350 ---help--- 2351 Linux can allow user programs to install a per-process x86 2352 Local Descriptor Table (LDT) using the modify_ldt(2) system 2353 call. This is required to run 16-bit or segmented code such as 2354 DOSEMU or some Wine programs. It is also used by some very old 2355 threading libraries. 2356 2357 Enabling this feature adds a small amount of overhead to 2358 context switches and increases the low-level kernel attack 2359 surface. Disabling it removes the modify_ldt(2) system call. 2360 2361 Saying 'N' here may make sense for embedded or server kernels. 2362 2363source "kernel/livepatch/Kconfig" 2364 2365endmenu 2366 2367config ARCH_HAS_ADD_PAGES 2368 def_bool y 2369 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2370 2371config ARCH_ENABLE_MEMORY_HOTPLUG 2372 def_bool y 2373 depends on X86_64 || (X86_32 && HIGHMEM) 2374 2375config ARCH_ENABLE_MEMORY_HOTREMOVE 2376 def_bool y 2377 depends on MEMORY_HOTPLUG 2378 2379config USE_PERCPU_NUMA_NODE_ID 2380 def_bool y 2381 depends on NUMA 2382 2383config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2384 def_bool y 2385 depends on X86_64 || X86_PAE 2386 2387config ARCH_ENABLE_HUGEPAGE_MIGRATION 2388 def_bool y 2389 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2390 2391config ARCH_ENABLE_THP_MIGRATION 2392 def_bool y 2393 depends on X86_64 && TRANSPARENT_HUGEPAGE 2394 2395menu "Power management and ACPI options" 2396 2397config ARCH_HIBERNATION_HEADER 2398 def_bool y 2399 depends on X86_64 && HIBERNATION 2400 2401source "kernel/power/Kconfig" 2402 2403source "drivers/acpi/Kconfig" 2404 2405source "drivers/sfi/Kconfig" 2406 2407config X86_APM_BOOT 2408 def_bool y 2409 depends on APM 2410 2411menuconfig APM 2412 tristate "APM (Advanced Power Management) BIOS support" 2413 depends on X86_32 && PM_SLEEP 2414 ---help--- 2415 APM is a BIOS specification for saving power using several different 2416 techniques. This is mostly useful for battery powered laptops with 2417 APM compliant BIOSes. If you say Y here, the system time will be 2418 reset after a RESUME operation, the /proc/apm device will provide 2419 battery status information, and user-space programs will receive 2420 notification of APM "events" (e.g. battery status change). 2421 2422 If you select "Y" here, you can disable actual use of the APM 2423 BIOS by passing the "apm=off" option to the kernel at boot time. 2424 2425 Note that the APM support is almost completely disabled for 2426 machines with more than one CPU. 2427 2428 In order to use APM, you will need supporting software. For location 2429 and more information, read <file:Documentation/power/apm-acpi.txt> 2430 and the Battery Powered Linux mini-HOWTO, available from 2431 <http://www.tldp.org/docs.html#howto>. 2432 2433 This driver does not spin down disk drives (see the hdparm(8) 2434 manpage ("man 8 hdparm") for that), and it doesn't turn off 2435 VESA-compliant "green" monitors. 2436 2437 This driver does not support the TI 4000M TravelMate and the ACER 2438 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2439 desktop machines also don't have compliant BIOSes, and this driver 2440 may cause those machines to panic during the boot phase. 2441 2442 Generally, if you don't have a battery in your machine, there isn't 2443 much point in using this driver and you should say N. If you get 2444 random kernel OOPSes or reboots that don't seem to be related to 2445 anything, try disabling/enabling this option (or disabling/enabling 2446 APM in your BIOS). 2447 2448 Some other things you should try when experiencing seemingly random, 2449 "weird" problems: 2450 2451 1) make sure that you have enough swap space and that it is 2452 enabled. 2453 2) pass the "no-hlt" option to the kernel 2454 3) switch on floating point emulation in the kernel and pass 2455 the "no387" option to the kernel 2456 4) pass the "floppy=nodma" option to the kernel 2457 5) pass the "mem=4M" option to the kernel (thereby disabling 2458 all but the first 4 MB of RAM) 2459 6) make sure that the CPU is not over clocked. 2460 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2461 8) disable the cache from your BIOS settings 2462 9) install a fan for the video card or exchange video RAM 2463 10) install a better fan for the CPU 2464 11) exchange RAM chips 2465 12) exchange the motherboard. 2466 2467 To compile this driver as a module, choose M here: the 2468 module will be called apm. 2469 2470if APM 2471 2472config APM_IGNORE_USER_SUSPEND 2473 bool "Ignore USER SUSPEND" 2474 ---help--- 2475 This option will ignore USER SUSPEND requests. On machines with a 2476 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2477 series notebooks, it is necessary to say Y because of a BIOS bug. 2478 2479config APM_DO_ENABLE 2480 bool "Enable PM at boot time" 2481 ---help--- 2482 Enable APM features at boot time. From page 36 of the APM BIOS 2483 specification: "When disabled, the APM BIOS does not automatically 2484 power manage devices, enter the Standby State, enter the Suspend 2485 State, or take power saving steps in response to CPU Idle calls." 2486 This driver will make CPU Idle calls when Linux is idle (unless this 2487 feature is turned off -- see "Do CPU IDLE calls", below). This 2488 should always save battery power, but more complicated APM features 2489 will be dependent on your BIOS implementation. You may need to turn 2490 this option off if your computer hangs at boot time when using APM 2491 support, or if it beeps continuously instead of suspending. Turn 2492 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2493 T400CDT. This is off by default since most machines do fine without 2494 this feature. 2495 2496config APM_CPU_IDLE 2497 depends on CPU_IDLE 2498 bool "Make CPU Idle calls when idle" 2499 ---help--- 2500 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2501 On some machines, this can activate improved power savings, such as 2502 a slowed CPU clock rate, when the machine is idle. These idle calls 2503 are made after the idle loop has run for some length of time (e.g., 2504 333 mS). On some machines, this will cause a hang at boot time or 2505 whenever the CPU becomes idle. (On machines with more than one CPU, 2506 this option does nothing.) 2507 2508config APM_DISPLAY_BLANK 2509 bool "Enable console blanking using APM" 2510 ---help--- 2511 Enable console blanking using the APM. Some laptops can use this to 2512 turn off the LCD backlight when the screen blanker of the Linux 2513 virtual console blanks the screen. Note that this is only used by 2514 the virtual console screen blanker, and won't turn off the backlight 2515 when using the X Window system. This also doesn't have anything to 2516 do with your VESA-compliant power-saving monitor. Further, this 2517 option doesn't work for all laptops -- it might not turn off your 2518 backlight at all, or it might print a lot of errors to the console, 2519 especially if you are using gpm. 2520 2521config APM_ALLOW_INTS 2522 bool "Allow interrupts during APM BIOS calls" 2523 ---help--- 2524 Normally we disable external interrupts while we are making calls to 2525 the APM BIOS as a measure to lessen the effects of a badly behaving 2526 BIOS implementation. The BIOS should reenable interrupts if it 2527 needs to. Unfortunately, some BIOSes do not -- especially those in 2528 many of the newer IBM Thinkpads. If you experience hangs when you 2529 suspend, try setting this to Y. Otherwise, say N. 2530 2531endif # APM 2532 2533source "drivers/cpufreq/Kconfig" 2534 2535source "drivers/cpuidle/Kconfig" 2536 2537source "drivers/idle/Kconfig" 2538 2539endmenu 2540 2541 2542menu "Bus options (PCI etc.)" 2543 2544config PCI 2545 bool "PCI support" 2546 default y 2547 ---help--- 2548 Find out whether you have a PCI motherboard. PCI is the name of a 2549 bus system, i.e. the way the CPU talks to the other stuff inside 2550 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or 2551 VESA. If you have PCI, say Y, otherwise N. 2552 2553choice 2554 prompt "PCI access mode" 2555 depends on X86_32 && PCI 2556 default PCI_GOANY 2557 ---help--- 2558 On PCI systems, the BIOS can be used to detect the PCI devices and 2559 determine their configuration. However, some old PCI motherboards 2560 have BIOS bugs and may crash if this is done. Also, some embedded 2561 PCI-based systems don't have any BIOS at all. Linux can also try to 2562 detect the PCI hardware directly without using the BIOS. 2563 2564 With this option, you can specify how Linux should detect the 2565 PCI devices. If you choose "BIOS", the BIOS will be used, 2566 if you choose "Direct", the BIOS won't be used, and if you 2567 choose "MMConfig", then PCI Express MMCONFIG will be used. 2568 If you choose "Any", the kernel will try MMCONFIG, then the 2569 direct access method and falls back to the BIOS if that doesn't 2570 work. If unsure, go with the default, which is "Any". 2571 2572config PCI_GOBIOS 2573 bool "BIOS" 2574 2575config PCI_GOMMCONFIG 2576 bool "MMConfig" 2577 2578config PCI_GODIRECT 2579 bool "Direct" 2580 2581config PCI_GOOLPC 2582 bool "OLPC XO-1" 2583 depends on OLPC 2584 2585config PCI_GOANY 2586 bool "Any" 2587 2588endchoice 2589 2590config PCI_BIOS 2591 def_bool y 2592 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2593 2594# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2595config PCI_DIRECT 2596 def_bool y 2597 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2598 2599config PCI_MMCONFIG 2600 def_bool y 2601 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY) 2602 2603config PCI_OLPC 2604 def_bool y 2605 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2606 2607config PCI_XEN 2608 def_bool y 2609 depends on PCI && XEN 2610 select SWIOTLB_XEN 2611 2612config PCI_DOMAINS 2613 def_bool y 2614 depends on PCI 2615 2616config PCI_MMCONFIG 2617 bool "Support mmconfig PCI config space access" 2618 depends on X86_64 && PCI && ACPI 2619 2620config PCI_CNB20LE_QUIRK 2621 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2622 depends on PCI 2623 help 2624 Read the PCI windows out of the CNB20LE host bridge. This allows 2625 PCI hotplug to work on systems with the CNB20LE chipset which do 2626 not have ACPI. 2627 2628 There's no public spec for this chipset, and this functionality 2629 is known to be incomplete. 2630 2631 You should say N unless you know you need this. 2632 2633source "drivers/pci/Kconfig" 2634 2635config ISA_BUS 2636 bool "ISA-style bus support on modern systems" if EXPERT 2637 select ISA_BUS_API 2638 help 2639 Enables ISA-style drivers on modern systems. This is necessary to 2640 support PC/104 devices on X86_64 platforms. 2641 2642 If unsure, say N. 2643 2644# x86_64 have no ISA slots, but can have ISA-style DMA. 2645config ISA_DMA_API 2646 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2647 default y 2648 help 2649 Enables ISA-style DMA support for devices requiring such controllers. 2650 If unsure, say Y. 2651 2652if X86_32 2653 2654config ISA 2655 bool "ISA support" 2656 ---help--- 2657 Find out whether you have ISA slots on your motherboard. ISA is the 2658 name of a bus system, i.e. the way the CPU talks to the other stuff 2659 inside your box. Other bus systems are PCI, EISA, MicroChannel 2660 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2661 newer boards don't support it. If you have ISA, say Y, otherwise N. 2662 2663config EISA 2664 bool "EISA support" 2665 depends on ISA 2666 ---help--- 2667 The Extended Industry Standard Architecture (EISA) bus was 2668 developed as an open alternative to the IBM MicroChannel bus. 2669 2670 The EISA bus provided some of the features of the IBM MicroChannel 2671 bus while maintaining backward compatibility with cards made for 2672 the older ISA bus. The EISA bus saw limited use between 1988 and 2673 1995 when it was made obsolete by the PCI bus. 2674 2675 Say Y here if you are building a kernel for an EISA-based machine. 2676 2677 Otherwise, say N. 2678 2679source "drivers/eisa/Kconfig" 2680 2681config SCx200 2682 tristate "NatSemi SCx200 support" 2683 ---help--- 2684 This provides basic support for National Semiconductor's 2685 (now AMD's) Geode processors. The driver probes for the 2686 PCI-IDs of several on-chip devices, so its a good dependency 2687 for other scx200_* drivers. 2688 2689 If compiled as a module, the driver is named scx200. 2690 2691config SCx200HR_TIMER 2692 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2693 depends on SCx200 2694 default y 2695 ---help--- 2696 This driver provides a clocksource built upon the on-chip 2697 27MHz high-resolution timer. Its also a workaround for 2698 NSC Geode SC-1100's buggy TSC, which loses time when the 2699 processor goes idle (as is done by the scheduler). The 2700 other workaround is idle=poll boot option. 2701 2702config OLPC 2703 bool "One Laptop Per Child support" 2704 depends on !X86_PAE 2705 select GPIOLIB 2706 select OF 2707 select OF_PROMTREE 2708 select IRQ_DOMAIN 2709 ---help--- 2710 Add support for detecting the unique features of the OLPC 2711 XO hardware. 2712 2713config OLPC_XO1_PM 2714 bool "OLPC XO-1 Power Management" 2715 depends on OLPC && MFD_CS5535 && PM_SLEEP 2716 select MFD_CORE 2717 ---help--- 2718 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2719 2720config OLPC_XO1_RTC 2721 bool "OLPC XO-1 Real Time Clock" 2722 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2723 ---help--- 2724 Add support for the XO-1 real time clock, which can be used as a 2725 programmable wakeup source. 2726 2727config OLPC_XO1_SCI 2728 bool "OLPC XO-1 SCI extras" 2729 depends on OLPC && OLPC_XO1_PM 2730 depends on INPUT=y 2731 select POWER_SUPPLY 2732 select GPIO_CS5535 2733 select MFD_CORE 2734 ---help--- 2735 Add support for SCI-based features of the OLPC XO-1 laptop: 2736 - EC-driven system wakeups 2737 - Power button 2738 - Ebook switch 2739 - Lid switch 2740 - AC adapter status updates 2741 - Battery status updates 2742 2743config OLPC_XO15_SCI 2744 bool "OLPC XO-1.5 SCI extras" 2745 depends on OLPC && ACPI 2746 select POWER_SUPPLY 2747 ---help--- 2748 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2749 - EC-driven system wakeups 2750 - AC adapter status updates 2751 - Battery status updates 2752 2753config ALIX 2754 bool "PCEngines ALIX System Support (LED setup)" 2755 select GPIOLIB 2756 ---help--- 2757 This option enables system support for the PCEngines ALIX. 2758 At present this just sets up LEDs for GPIO control on 2759 ALIX2/3/6 boards. However, other system specific setup should 2760 get added here. 2761 2762 Note: You must still enable the drivers for GPIO and LED support 2763 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2764 2765 Note: You have to set alix.force=1 for boards with Award BIOS. 2766 2767config NET5501 2768 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2769 select GPIOLIB 2770 ---help--- 2771 This option enables system support for the Soekris Engineering net5501. 2772 2773config GEOS 2774 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2775 select GPIOLIB 2776 depends on DMI 2777 ---help--- 2778 This option enables system support for the Traverse Technologies GEOS. 2779 2780config TS5500 2781 bool "Technologic Systems TS-5500 platform support" 2782 depends on MELAN 2783 select CHECK_SIGNATURE 2784 select NEW_LEDS 2785 select LEDS_CLASS 2786 ---help--- 2787 This option enables system support for the Technologic Systems TS-5500. 2788 2789endif # X86_32 2790 2791config AMD_NB 2792 def_bool y 2793 depends on CPU_SUP_AMD && PCI 2794 2795source "drivers/pcmcia/Kconfig" 2796 2797config RAPIDIO 2798 tristate "RapidIO support" 2799 depends on PCI 2800 default n 2801 help 2802 If enabled this option will include drivers and the core 2803 infrastructure code to support RapidIO interconnect devices. 2804 2805source "drivers/rapidio/Kconfig" 2806 2807config X86_SYSFB 2808 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2809 help 2810 Firmwares often provide initial graphics framebuffers so the BIOS, 2811 bootloader or kernel can show basic video-output during boot for 2812 user-guidance and debugging. Historically, x86 used the VESA BIOS 2813 Extensions and EFI-framebuffers for this, which are mostly limited 2814 to x86. 2815 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2816 framebuffers so the new generic system-framebuffer drivers can be 2817 used on x86. If the framebuffer is not compatible with the generic 2818 modes, it is adverticed as fallback platform framebuffer so legacy 2819 drivers like efifb, vesafb and uvesafb can pick it up. 2820 If this option is not selected, all system framebuffers are always 2821 marked as fallback platform framebuffers as usual. 2822 2823 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2824 not be able to pick up generic system framebuffers if this option 2825 is selected. You are highly encouraged to enable simplefb as 2826 replacement if you select this option. simplefb can correctly deal 2827 with generic system framebuffers. But you should still keep vesafb 2828 and others enabled as fallback if a system framebuffer is 2829 incompatible with simplefb. 2830 2831 If unsure, say Y. 2832 2833endmenu 2834 2835 2836menu "Executable file formats / Emulations" 2837 2838source "fs/Kconfig.binfmt" 2839 2840config IA32_EMULATION 2841 bool "IA32 Emulation" 2842 depends on X86_64 2843 select ARCH_WANT_OLD_COMPAT_IPC 2844 select BINFMT_ELF 2845 select COMPAT_BINFMT_ELF 2846 select COMPAT_OLD_SIGACTION 2847 ---help--- 2848 Include code to run legacy 32-bit programs under a 2849 64-bit kernel. You should likely turn this on, unless you're 2850 100% sure that you don't have any 32-bit programs left. 2851 2852config IA32_AOUT 2853 tristate "IA32 a.out support" 2854 depends on IA32_EMULATION 2855 ---help--- 2856 Support old a.out binaries in the 32bit emulation. 2857 2858config X86_X32 2859 bool "x32 ABI for 64-bit mode" 2860 depends on X86_64 2861 ---help--- 2862 Include code to run binaries for the x32 native 32-bit ABI 2863 for 64-bit processors. An x32 process gets access to the 2864 full 64-bit register file and wide data path while leaving 2865 pointers at 32 bits for smaller memory footprint. 2866 2867 You will need a recent binutils (2.22 or later) with 2868 elf32_x86_64 support enabled to compile a kernel with this 2869 option set. 2870 2871config COMPAT_32 2872 def_bool y 2873 depends on IA32_EMULATION || X86_32 2874 select HAVE_UID16 2875 select OLD_SIGSUSPEND3 2876 2877config COMPAT 2878 def_bool y 2879 depends on IA32_EMULATION || X86_X32 2880 2881if COMPAT 2882config COMPAT_FOR_U64_ALIGNMENT 2883 def_bool y 2884 2885config SYSVIPC_COMPAT 2886 def_bool y 2887 depends on SYSVIPC 2888endif 2889 2890endmenu 2891 2892 2893config HAVE_ATOMIC_IOMAP 2894 def_bool y 2895 depends on X86_32 2896 2897config X86_DEV_DMA_OPS 2898 bool 2899 depends on X86_64 || STA2X11 2900 2901config X86_DMA_REMAP 2902 bool 2903 depends on STA2X11 2904 2905config HAVE_GENERIC_GUP 2906 def_bool y 2907 2908source "net/Kconfig" 2909 2910source "drivers/Kconfig" 2911 2912source "drivers/firmware/Kconfig" 2913 2914source "fs/Kconfig" 2915 2916source "arch/x86/Kconfig.debug" 2917 2918source "security/Kconfig" 2919 2920source "crypto/Kconfig" 2921 2922source "arch/x86/kvm/Kconfig" 2923 2924source "lib/Kconfig" 2925