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 select ARCH_HAS_SYSCALL_WRAPPER 33 34# 35# Arch settings 36# 37# ( Note that options that are marked 'if X86_64' could in principle be 38# ported to 32-bit as well. ) 39# 40config X86 41 def_bool y 42 # 43 # Note: keep this list sorted alphabetically 44 # 45 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 46 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 47 select ANON_INODES 48 select ARCH_CLOCKSOURCE_DATA 49 select ARCH_DISCARD_MEMBLOCK 50 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 51 select ARCH_HAS_DEBUG_VIRTUAL 52 select ARCH_HAS_DEVMEM_IS_ALLOWED 53 select ARCH_HAS_ELF_RANDOMIZE 54 select ARCH_HAS_FAST_MULTIPLIER 55 select ARCH_HAS_FILTER_PGPROT 56 select ARCH_HAS_FORTIFY_SOURCE 57 select ARCH_HAS_GCOV_PROFILE_ALL 58 select ARCH_HAS_KCOV if X86_64 59 select ARCH_HAS_MEMBARRIER_SYNC_CORE 60 select ARCH_HAS_PMEM_API if X86_64 61 select ARCH_HAS_REFCOUNT 62 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 63 select ARCH_HAS_SET_MEMORY 64 select ARCH_HAS_SG_CHAIN 65 select ARCH_HAS_STRICT_KERNEL_RWX 66 select ARCH_HAS_STRICT_MODULE_RWX 67 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 68 select ARCH_HAS_UBSAN_SANITIZE_ALL 69 select ARCH_HAS_ZONE_DEVICE if X86_64 70 select ARCH_HAVE_NMI_SAFE_CMPXCHG 71 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 72 select ARCH_MIGHT_HAVE_PC_PARPORT 73 select ARCH_MIGHT_HAVE_PC_SERIO 74 select ARCH_SUPPORTS_ATOMIC_RMW 75 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 76 select ARCH_USE_BUILTIN_BSWAP 77 select ARCH_USE_QUEUED_RWLOCKS 78 select ARCH_USE_QUEUED_SPINLOCKS 79 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 80 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 81 select ARCH_WANTS_THP_SWAP if X86_64 82 select BUILDTIME_EXTABLE_SORT 83 select CLKEVT_I8253 84 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 85 select CLOCKSOURCE_WATCHDOG 86 select DCACHE_WORD_ACCESS 87 select DMA_DIRECT_OPS 88 select EDAC_ATOMIC_SCRUB 89 select EDAC_SUPPORT 90 select GENERIC_CLOCKEVENTS 91 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 92 select GENERIC_CLOCKEVENTS_MIN_ADJUST 93 select GENERIC_CMOS_UPDATE 94 select GENERIC_CPU_AUTOPROBE 95 select GENERIC_CPU_VULNERABILITIES 96 select GENERIC_EARLY_IOREMAP 97 select GENERIC_FIND_FIRST_BIT 98 select GENERIC_IOMAP 99 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 100 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 101 select GENERIC_IRQ_MIGRATION if SMP 102 select GENERIC_IRQ_PROBE 103 select GENERIC_IRQ_RESERVATION_MODE 104 select GENERIC_IRQ_SHOW 105 select GENERIC_PENDING_IRQ if SMP 106 select GENERIC_SMP_IDLE_THREAD 107 select GENERIC_STRNCPY_FROM_USER 108 select GENERIC_STRNLEN_USER 109 select GENERIC_TIME_VSYSCALL 110 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 111 select HAVE_ACPI_APEI if ACPI 112 select HAVE_ACPI_APEI_NMI if ACPI 113 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 114 select HAVE_ARCH_AUDITSYSCALL 115 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 116 select HAVE_ARCH_JUMP_LABEL 117 select HAVE_ARCH_KASAN if X86_64 118 select HAVE_ARCH_KGDB 119 select HAVE_ARCH_MMAP_RND_BITS if MMU 120 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 121 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 122 select HAVE_ARCH_SECCOMP_FILTER 123 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 124 select HAVE_ARCH_TRACEHOOK 125 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 126 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 127 select HAVE_ARCH_VMAP_STACK if X86_64 128 select HAVE_ARCH_WITHIN_STACK_FRAMES 129 select HAVE_CC_STACKPROTECTOR 130 select HAVE_CMPXCHG_DOUBLE 131 select HAVE_CMPXCHG_LOCAL 132 select HAVE_CONTEXT_TRACKING if X86_64 133 select HAVE_COPY_THREAD_TLS 134 select HAVE_C_RECORDMCOUNT 135 select HAVE_DEBUG_KMEMLEAK 136 select HAVE_DEBUG_STACKOVERFLOW 137 select HAVE_DMA_API_DEBUG 138 select HAVE_DMA_CONTIGUOUS 139 select HAVE_DYNAMIC_FTRACE 140 select HAVE_DYNAMIC_FTRACE_WITH_REGS 141 select HAVE_EBPF_JIT 142 select HAVE_EFFICIENT_UNALIGNED_ACCESS 143 select HAVE_EXIT_THREAD 144 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 145 select HAVE_FTRACE_MCOUNT_RECORD 146 select HAVE_FUNCTION_GRAPH_TRACER 147 select HAVE_FUNCTION_TRACER 148 select HAVE_GCC_PLUGINS 149 select HAVE_HW_BREAKPOINT 150 select HAVE_IDE 151 select HAVE_IOREMAP_PROT 152 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 153 select HAVE_IRQ_TIME_ACCOUNTING 154 select HAVE_KERNEL_BZIP2 155 select HAVE_KERNEL_GZIP 156 select HAVE_KERNEL_LZ4 157 select HAVE_KERNEL_LZMA 158 select HAVE_KERNEL_LZO 159 select HAVE_KERNEL_XZ 160 select HAVE_KPROBES 161 select HAVE_KPROBES_ON_FTRACE 162 select HAVE_FUNCTION_ERROR_INJECTION 163 select HAVE_KRETPROBES 164 select HAVE_KVM 165 select HAVE_LIVEPATCH if X86_64 166 select HAVE_MEMBLOCK 167 select HAVE_MEMBLOCK_NODE_MAP 168 select HAVE_MIXED_BREAKPOINTS_REGS 169 select HAVE_MOD_ARCH_SPECIFIC 170 select HAVE_NMI 171 select HAVE_OPROFILE 172 select HAVE_OPTPROBES 173 select HAVE_PCSPKR_PLATFORM 174 select HAVE_PERF_EVENTS 175 select HAVE_PERF_EVENTS_NMI 176 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 177 select HAVE_PERF_REGS 178 select HAVE_PERF_USER_STACK_DUMP 179 select HAVE_RCU_TABLE_FREE 180 select HAVE_REGS_AND_STACK_ACCESS_API 181 select HAVE_RELIABLE_STACKTRACE if X86_64 && UNWINDER_FRAME_POINTER && STACK_VALIDATION 182 select HAVE_STACK_VALIDATION if X86_64 183 select HAVE_SYSCALL_TRACEPOINTS 184 select HAVE_UNSTABLE_SCHED_CLOCK 185 select HAVE_USER_RETURN_NOTIFIER 186 select IRQ_FORCED_THREADING 187 select PCI_LOCKLESS_CONFIG 188 select PERF_EVENTS 189 select RTC_LIB 190 select RTC_MC146818_LIB 191 select SPARSE_IRQ 192 select SRCU 193 select SYSCTL_EXCEPTION_TRACE 194 select THREAD_INFO_IN_TASK 195 select USER_STACKTRACE_SUPPORT 196 select VIRT_TO_BUS 197 select X86_FEATURE_NAMES if PROC_FS 198 199config INSTRUCTION_DECODER 200 def_bool y 201 depends on KPROBES || PERF_EVENTS || UPROBES 202 203config OUTPUT_FORMAT 204 string 205 default "elf32-i386" if X86_32 206 default "elf64-x86-64" if X86_64 207 208config ARCH_DEFCONFIG 209 string 210 default "arch/x86/configs/i386_defconfig" if X86_32 211 default "arch/x86/configs/x86_64_defconfig" if X86_64 212 213config LOCKDEP_SUPPORT 214 def_bool y 215 216config STACKTRACE_SUPPORT 217 def_bool y 218 219config MMU 220 def_bool y 221 222config ARCH_MMAP_RND_BITS_MIN 223 default 28 if 64BIT 224 default 8 225 226config ARCH_MMAP_RND_BITS_MAX 227 default 32 if 64BIT 228 default 16 229 230config ARCH_MMAP_RND_COMPAT_BITS_MIN 231 default 8 232 233config ARCH_MMAP_RND_COMPAT_BITS_MAX 234 default 16 235 236config SBUS 237 bool 238 239config NEED_DMA_MAP_STATE 240 def_bool y 241 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB 242 243config NEED_SG_DMA_LENGTH 244 def_bool y 245 246config GENERIC_ISA_DMA 247 def_bool y 248 depends on ISA_DMA_API 249 250config GENERIC_BUG 251 def_bool y 252 depends on BUG 253 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 254 255config GENERIC_BUG_RELATIVE_POINTERS 256 bool 257 258config GENERIC_HWEIGHT 259 def_bool y 260 261config ARCH_MAY_HAVE_PC_FDC 262 def_bool y 263 depends on ISA_DMA_API 264 265config RWSEM_XCHGADD_ALGORITHM 266 def_bool y 267 268config GENERIC_CALIBRATE_DELAY 269 def_bool y 270 271config ARCH_HAS_CPU_RELAX 272 def_bool y 273 274config ARCH_HAS_CACHE_LINE_SIZE 275 def_bool y 276 277config ARCH_HAS_FILTER_PGPROT 278 def_bool y 279 280config HAVE_SETUP_PER_CPU_AREA 281 def_bool y 282 283config NEED_PER_CPU_EMBED_FIRST_CHUNK 284 def_bool y 285 286config NEED_PER_CPU_PAGE_FIRST_CHUNK 287 def_bool y 288 289config ARCH_HIBERNATION_POSSIBLE 290 def_bool y 291 292config ARCH_SUSPEND_POSSIBLE 293 def_bool y 294 295config ARCH_WANT_HUGE_PMD_SHARE 296 def_bool y 297 298config ARCH_WANT_GENERAL_HUGETLB 299 def_bool y 300 301config ZONE_DMA32 302 def_bool y if X86_64 303 304config AUDIT_ARCH 305 def_bool y if X86_64 306 307config ARCH_SUPPORTS_OPTIMIZED_INLINING 308 def_bool y 309 310config ARCH_SUPPORTS_DEBUG_PAGEALLOC 311 def_bool y 312 313config KASAN_SHADOW_OFFSET 314 hex 315 depends on KASAN 316 default 0xdffffc0000000000 317 318config HAVE_INTEL_TXT 319 def_bool y 320 depends on INTEL_IOMMU && ACPI 321 322config X86_32_SMP 323 def_bool y 324 depends on X86_32 && SMP 325 326config X86_64_SMP 327 def_bool y 328 depends on X86_64 && SMP 329 330config X86_32_LAZY_GS 331 def_bool y 332 depends on X86_32 && CC_STACKPROTECTOR_NONE 333 334config ARCH_SUPPORTS_UPROBES 335 def_bool y 336 337config FIX_EARLYCON_MEM 338 def_bool y 339 340config PGTABLE_LEVELS 341 int 342 default 5 if X86_5LEVEL 343 default 4 if X86_64 344 default 3 if X86_PAE 345 default 2 346 347source "init/Kconfig" 348source "kernel/Kconfig.freezer" 349 350menu "Processor type and features" 351 352config ZONE_DMA 353 bool "DMA memory allocation support" if EXPERT 354 default y 355 help 356 DMA memory allocation support allows devices with less than 32-bit 357 addressing to allocate within the first 16MB of address space. 358 Disable if no such devices will be used. 359 360 If unsure, say Y. 361 362config SMP 363 bool "Symmetric multi-processing support" 364 ---help--- 365 This enables support for systems with more than one CPU. If you have 366 a system with only one CPU, say N. If you have a system with more 367 than one CPU, say Y. 368 369 If you say N here, the kernel will run on uni- and multiprocessor 370 machines, but will use only one CPU of a multiprocessor machine. If 371 you say Y here, the kernel will run on many, but not all, 372 uniprocessor machines. On a uniprocessor machine, the kernel 373 will run faster if you say N here. 374 375 Note that if you say Y here and choose architecture "586" or 376 "Pentium" under "Processor family", the kernel will not work on 486 377 architectures. Similarly, multiprocessor kernels for the "PPro" 378 architecture may not work on all Pentium based boards. 379 380 People using multiprocessor machines who say Y here should also say 381 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 382 Management" code will be disabled if you say Y here. 383 384 See also <file:Documentation/x86/i386/IO-APIC.txt>, 385 <file:Documentation/lockup-watchdogs.txt> and the SMP-HOWTO available at 386 <http://www.tldp.org/docs.html#howto>. 387 388 If you don't know what to do here, say N. 389 390config X86_FEATURE_NAMES 391 bool "Processor feature human-readable names" if EMBEDDED 392 default y 393 ---help--- 394 This option compiles in a table of x86 feature bits and corresponding 395 names. This is required to support /proc/cpuinfo and a few kernel 396 messages. You can disable this to save space, at the expense of 397 making those few kernel messages show numeric feature bits instead. 398 399 If in doubt, say Y. 400 401config X86_X2APIC 402 bool "Support x2apic" 403 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 404 ---help--- 405 This enables x2apic support on CPUs that have this feature. 406 407 This allows 32-bit apic IDs (so it can support very large systems), 408 and accesses the local apic via MSRs not via mmio. 409 410 If you don't know what to do here, say N. 411 412config X86_MPPARSE 413 bool "Enable MPS table" if ACPI || SFI 414 default y 415 depends on X86_LOCAL_APIC 416 ---help--- 417 For old smp systems that do not have proper acpi support. Newer systems 418 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 419 420config GOLDFISH 421 def_bool y 422 depends on X86_GOLDFISH 423 424config RETPOLINE 425 bool "Avoid speculative indirect branches in kernel" 426 default y 427 select STACK_VALIDATION if HAVE_STACK_VALIDATION 428 help 429 Compile kernel with the retpoline compiler options to guard against 430 kernel-to-user data leaks by avoiding speculative indirect 431 branches. Requires a compiler with -mindirect-branch=thunk-extern 432 support for full protection. The kernel may run slower. 433 434 Without compiler support, at least indirect branches in assembler 435 code are eliminated. Since this includes the syscall entry path, 436 it is not entirely pointless. 437 438config INTEL_RDT 439 bool "Intel Resource Director Technology support" 440 default n 441 depends on X86 && CPU_SUP_INTEL 442 select KERNFS 443 help 444 Select to enable resource allocation and monitoring which are 445 sub-features of Intel Resource Director Technology(RDT). More 446 information about RDT can be found in the Intel x86 447 Architecture Software Developer Manual. 448 449 Say N if unsure. 450 451if X86_32 452config X86_BIGSMP 453 bool "Support for big SMP systems with more than 8 CPUs" 454 depends on SMP 455 ---help--- 456 This option is needed for the systems that have more than 8 CPUs 457 458config X86_EXTENDED_PLATFORM 459 bool "Support for extended (non-PC) x86 platforms" 460 default y 461 ---help--- 462 If you disable this option then the kernel will only support 463 standard PC platforms. (which covers the vast majority of 464 systems out there.) 465 466 If you enable this option then you'll be able to select support 467 for the following (non-PC) 32 bit x86 platforms: 468 Goldfish (Android emulator) 469 AMD Elan 470 RDC R-321x SoC 471 SGI 320/540 (Visual Workstation) 472 STA2X11-based (e.g. Northville) 473 Moorestown MID devices 474 475 If you have one of these systems, or if you want to build a 476 generic distribution kernel, say Y here - otherwise say N. 477endif 478 479if X86_64 480config X86_EXTENDED_PLATFORM 481 bool "Support for extended (non-PC) x86 platforms" 482 default y 483 ---help--- 484 If you disable this option then the kernel will only support 485 standard PC platforms. (which covers the vast majority of 486 systems out there.) 487 488 If you enable this option then you'll be able to select support 489 for the following (non-PC) 64 bit x86 platforms: 490 Numascale NumaChip 491 ScaleMP vSMP 492 SGI Ultraviolet 493 494 If you have one of these systems, or if you want to build a 495 generic distribution kernel, say Y here - otherwise say N. 496endif 497# This is an alphabetically sorted list of 64 bit extended platforms 498# Please maintain the alphabetic order if and when there are additions 499config X86_NUMACHIP 500 bool "Numascale NumaChip" 501 depends on X86_64 502 depends on X86_EXTENDED_PLATFORM 503 depends on NUMA 504 depends on SMP 505 depends on X86_X2APIC 506 depends on PCI_MMCONFIG 507 ---help--- 508 Adds support for Numascale NumaChip large-SMP systems. Needed to 509 enable more than ~168 cores. 510 If you don't have one of these, you should say N here. 511 512config X86_VSMP 513 bool "ScaleMP vSMP" 514 select HYPERVISOR_GUEST 515 select PARAVIRT 516 depends on X86_64 && PCI 517 depends on X86_EXTENDED_PLATFORM 518 depends on SMP 519 ---help--- 520 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 521 supposed to run on these EM64T-based machines. Only choose this option 522 if you have one of these machines. 523 524config X86_UV 525 bool "SGI Ultraviolet" 526 depends on X86_64 527 depends on X86_EXTENDED_PLATFORM 528 depends on NUMA 529 depends on EFI 530 depends on X86_X2APIC 531 depends on PCI 532 ---help--- 533 This option is needed in order to support SGI Ultraviolet systems. 534 If you don't have one of these, you should say N here. 535 536# Following is an alphabetically sorted list of 32 bit extended platforms 537# Please maintain the alphabetic order if and when there are additions 538 539config X86_GOLDFISH 540 bool "Goldfish (Virtual Platform)" 541 depends on X86_EXTENDED_PLATFORM 542 ---help--- 543 Enable support for the Goldfish virtual platform used primarily 544 for Android development. Unless you are building for the Android 545 Goldfish emulator say N here. 546 547config X86_INTEL_CE 548 bool "CE4100 TV platform" 549 depends on PCI 550 depends on PCI_GODIRECT 551 depends on X86_IO_APIC 552 depends on X86_32 553 depends on X86_EXTENDED_PLATFORM 554 select X86_REBOOTFIXUPS 555 select OF 556 select OF_EARLY_FLATTREE 557 ---help--- 558 Select for the Intel CE media processor (CE4100) SOC. 559 This option compiles in support for the CE4100 SOC for settop 560 boxes and media devices. 561 562config X86_INTEL_MID 563 bool "Intel MID platform support" 564 depends on X86_EXTENDED_PLATFORM 565 depends on X86_PLATFORM_DEVICES 566 depends on PCI 567 depends on X86_64 || (PCI_GOANY && X86_32) 568 depends on X86_IO_APIC 569 select SFI 570 select I2C 571 select DW_APB_TIMER 572 select APB_TIMER 573 select INTEL_SCU_IPC 574 select MFD_INTEL_MSIC 575 ---help--- 576 Select to build a kernel capable of supporting Intel MID (Mobile 577 Internet Device) platform systems which do not have the PCI legacy 578 interfaces. If you are building for a PC class system say N here. 579 580 Intel MID platforms are based on an Intel processor and chipset which 581 consume less power than most of the x86 derivatives. 582 583config X86_INTEL_QUARK 584 bool "Intel Quark platform support" 585 depends on X86_32 586 depends on X86_EXTENDED_PLATFORM 587 depends on X86_PLATFORM_DEVICES 588 depends on X86_TSC 589 depends on PCI 590 depends on PCI_GOANY 591 depends on X86_IO_APIC 592 select IOSF_MBI 593 select INTEL_IMR 594 select COMMON_CLK 595 ---help--- 596 Select to include support for Quark X1000 SoC. 597 Say Y here if you have a Quark based system such as the Arduino 598 compatible Intel Galileo. 599 600config X86_INTEL_LPSS 601 bool "Intel Low Power Subsystem Support" 602 depends on X86 && ACPI 603 select COMMON_CLK 604 select PINCTRL 605 select IOSF_MBI 606 ---help--- 607 Select to build support for Intel Low Power Subsystem such as 608 found on Intel Lynxpoint PCH. Selecting this option enables 609 things like clock tree (common clock framework) and pincontrol 610 which are needed by the LPSS peripheral drivers. 611 612config X86_AMD_PLATFORM_DEVICE 613 bool "AMD ACPI2Platform devices support" 614 depends on ACPI 615 select COMMON_CLK 616 select PINCTRL 617 ---help--- 618 Select to interpret AMD specific ACPI device to platform device 619 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 620 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 621 implemented under PINCTRL subsystem. 622 623config IOSF_MBI 624 tristate "Intel SoC IOSF Sideband support for SoC platforms" 625 depends on PCI 626 ---help--- 627 This option enables sideband register access support for Intel SoC 628 platforms. On these platforms the IOSF sideband is used in lieu of 629 MSR's for some register accesses, mostly but not limited to thermal 630 and power. Drivers may query the availability of this device to 631 determine if they need the sideband in order to work on these 632 platforms. The sideband is available on the following SoC products. 633 This list is not meant to be exclusive. 634 - BayTrail 635 - Braswell 636 - Quark 637 638 You should say Y if you are running a kernel on one of these SoC's. 639 640config IOSF_MBI_DEBUG 641 bool "Enable IOSF sideband access through debugfs" 642 depends on IOSF_MBI && DEBUG_FS 643 ---help--- 644 Select this option to expose the IOSF sideband access registers (MCR, 645 MDR, MCRX) through debugfs to write and read register information from 646 different units on the SoC. This is most useful for obtaining device 647 state information for debug and analysis. As this is a general access 648 mechanism, users of this option would have specific knowledge of the 649 device they want to access. 650 651 If you don't require the option or are in doubt, say N. 652 653config X86_RDC321X 654 bool "RDC R-321x SoC" 655 depends on X86_32 656 depends on X86_EXTENDED_PLATFORM 657 select M486 658 select X86_REBOOTFIXUPS 659 ---help--- 660 This option is needed for RDC R-321x system-on-chip, also known 661 as R-8610-(G). 662 If you don't have one of these chips, you should say N here. 663 664config X86_32_NON_STANDARD 665 bool "Support non-standard 32-bit SMP architectures" 666 depends on X86_32 && SMP 667 depends on X86_EXTENDED_PLATFORM 668 ---help--- 669 This option compiles in the bigsmp and STA2X11 default 670 subarchitectures. It is intended for a generic binary 671 kernel. If you select them all, kernel will probe it one by 672 one and will fallback to default. 673 674# Alphabetically sorted list of Non standard 32 bit platforms 675 676config X86_SUPPORTS_MEMORY_FAILURE 677 def_bool y 678 # MCE code calls memory_failure(): 679 depends on X86_MCE 680 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 681 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 682 depends on X86_64 || !SPARSEMEM 683 select ARCH_SUPPORTS_MEMORY_FAILURE 684 685config STA2X11 686 bool "STA2X11 Companion Chip Support" 687 depends on X86_32_NON_STANDARD && PCI 688 select ARCH_HAS_PHYS_TO_DMA 689 select X86_DEV_DMA_OPS 690 select X86_DMA_REMAP 691 select SWIOTLB 692 select MFD_STA2X11 693 select GPIOLIB 694 default n 695 ---help--- 696 This adds support for boards based on the STA2X11 IO-Hub, 697 a.k.a. "ConneXt". The chip is used in place of the standard 698 PC chipset, so all "standard" peripherals are missing. If this 699 option is selected the kernel will still be able to boot on 700 standard PC machines. 701 702config X86_32_IRIS 703 tristate "Eurobraille/Iris poweroff module" 704 depends on X86_32 705 ---help--- 706 The Iris machines from EuroBraille do not have APM or ACPI support 707 to shut themselves down properly. A special I/O sequence is 708 needed to do so, which is what this module does at 709 kernel shutdown. 710 711 This is only for Iris machines from EuroBraille. 712 713 If unused, say N. 714 715config SCHED_OMIT_FRAME_POINTER 716 def_bool y 717 prompt "Single-depth WCHAN output" 718 depends on X86 719 ---help--- 720 Calculate simpler /proc/<PID>/wchan values. If this option 721 is disabled then wchan values will recurse back to the 722 caller function. This provides more accurate wchan values, 723 at the expense of slightly more scheduling overhead. 724 725 If in doubt, say "Y". 726 727menuconfig HYPERVISOR_GUEST 728 bool "Linux guest support" 729 ---help--- 730 Say Y here to enable options for running Linux under various hyper- 731 visors. This option enables basic hypervisor detection and platform 732 setup. 733 734 If you say N, all options in this submenu will be skipped and 735 disabled, and Linux guest support won't be built in. 736 737if HYPERVISOR_GUEST 738 739config PARAVIRT 740 bool "Enable paravirtualization code" 741 ---help--- 742 This changes the kernel so it can modify itself when it is run 743 under a hypervisor, potentially improving performance significantly 744 over full virtualization. However, when run without a hypervisor 745 the kernel is theoretically slower and slightly larger. 746 747config PARAVIRT_DEBUG 748 bool "paravirt-ops debugging" 749 depends on PARAVIRT && DEBUG_KERNEL 750 ---help--- 751 Enable to debug paravirt_ops internals. Specifically, BUG if 752 a paravirt_op is missing when it is called. 753 754config PARAVIRT_SPINLOCKS 755 bool "Paravirtualization layer for spinlocks" 756 depends on PARAVIRT && SMP 757 ---help--- 758 Paravirtualized spinlocks allow a pvops backend to replace the 759 spinlock implementation with something virtualization-friendly 760 (for example, block the virtual CPU rather than spinning). 761 762 It has a minimal impact on native kernels and gives a nice performance 763 benefit on paravirtualized KVM / Xen kernels. 764 765 If you are unsure how to answer this question, answer Y. 766 767config QUEUED_LOCK_STAT 768 bool "Paravirt queued spinlock statistics" 769 depends on PARAVIRT_SPINLOCKS && DEBUG_FS 770 ---help--- 771 Enable the collection of statistical data on the slowpath 772 behavior of paravirtualized queued spinlocks and report 773 them on debugfs. 774 775source "arch/x86/xen/Kconfig" 776 777config KVM_GUEST 778 bool "KVM Guest support (including kvmclock)" 779 depends on PARAVIRT 780 select PARAVIRT_CLOCK 781 default y 782 ---help--- 783 This option enables various optimizations for running under the KVM 784 hypervisor. It includes a paravirtualized clock, so that instead 785 of relying on a PIT (or probably other) emulation by the 786 underlying device model, the host provides the guest with 787 timing infrastructure such as time of day, and system time 788 789config KVM_DEBUG_FS 790 bool "Enable debug information for KVM Guests in debugfs" 791 depends on KVM_GUEST && DEBUG_FS 792 default n 793 ---help--- 794 This option enables collection of various statistics for KVM guest. 795 Statistics are displayed in debugfs filesystem. Enabling this option 796 may incur significant overhead. 797 798config PARAVIRT_TIME_ACCOUNTING 799 bool "Paravirtual steal time accounting" 800 depends on PARAVIRT 801 default n 802 ---help--- 803 Select this option to enable fine granularity task steal time 804 accounting. Time spent executing other tasks in parallel with 805 the current vCPU is discounted from the vCPU power. To account for 806 that, there can be a small performance impact. 807 808 If in doubt, say N here. 809 810config PARAVIRT_CLOCK 811 bool 812 813config JAILHOUSE_GUEST 814 bool "Jailhouse non-root cell support" 815 depends on X86_64 && PCI 816 select X86_PM_TIMER 817 ---help--- 818 This option allows to run Linux as guest in a Jailhouse non-root 819 cell. You can leave this option disabled if you only want to start 820 Jailhouse and run Linux afterwards in the root cell. 821 822endif #HYPERVISOR_GUEST 823 824config NO_BOOTMEM 825 def_bool y 826 827source "arch/x86/Kconfig.cpu" 828 829config HPET_TIMER 830 def_bool X86_64 831 prompt "HPET Timer Support" if X86_32 832 ---help--- 833 Use the IA-PC HPET (High Precision Event Timer) to manage 834 time in preference to the PIT and RTC, if a HPET is 835 present. 836 HPET is the next generation timer replacing legacy 8254s. 837 The HPET provides a stable time base on SMP 838 systems, unlike the TSC, but it is more expensive to access, 839 as it is off-chip. The interface used is documented 840 in the HPET spec, revision 1. 841 842 You can safely choose Y here. However, HPET will only be 843 activated if the platform and the BIOS support this feature. 844 Otherwise the 8254 will be used for timing services. 845 846 Choose N to continue using the legacy 8254 timer. 847 848config HPET_EMULATE_RTC 849 def_bool y 850 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 851 852config APB_TIMER 853 def_bool y if X86_INTEL_MID 854 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 855 select DW_APB_TIMER 856 depends on X86_INTEL_MID && SFI 857 help 858 APB timer is the replacement for 8254, HPET on X86 MID platforms. 859 The APBT provides a stable time base on SMP 860 systems, unlike the TSC, but it is more expensive to access, 861 as it is off-chip. APB timers are always running regardless of CPU 862 C states, they are used as per CPU clockevent device when possible. 863 864# Mark as expert because too many people got it wrong. 865# The code disables itself when not needed. 866config DMI 867 default y 868 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 869 bool "Enable DMI scanning" if EXPERT 870 ---help--- 871 Enabled scanning of DMI to identify machine quirks. Say Y 872 here unless you have verified that your setup is not 873 affected by entries in the DMI blacklist. Required by PNP 874 BIOS code. 875 876config GART_IOMMU 877 bool "Old AMD GART IOMMU support" 878 select SWIOTLB 879 depends on X86_64 && PCI && AMD_NB 880 ---help--- 881 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 882 GART based hardware IOMMUs. 883 884 The GART supports full DMA access for devices with 32-bit access 885 limitations, on systems with more than 3 GB. This is usually needed 886 for USB, sound, many IDE/SATA chipsets and some other devices. 887 888 Newer systems typically have a modern AMD IOMMU, supported via 889 the CONFIG_AMD_IOMMU=y config option. 890 891 In normal configurations this driver is only active when needed: 892 there's more than 3 GB of memory and the system contains a 893 32-bit limited device. 894 895 If unsure, say Y. 896 897config CALGARY_IOMMU 898 bool "IBM Calgary IOMMU support" 899 select SWIOTLB 900 depends on X86_64 && PCI 901 ---help--- 902 Support for hardware IOMMUs in IBM's xSeries x366 and x460 903 systems. Needed to run systems with more than 3GB of memory 904 properly with 32-bit PCI devices that do not support DAC 905 (Double Address Cycle). Calgary also supports bus level 906 isolation, where all DMAs pass through the IOMMU. This 907 prevents them from going anywhere except their intended 908 destination. This catches hard-to-find kernel bugs and 909 mis-behaving drivers and devices that do not use the DMA-API 910 properly to set up their DMA buffers. The IOMMU can be 911 turned off at boot time with the iommu=off parameter. 912 Normally the kernel will make the right choice by itself. 913 If unsure, say Y. 914 915config CALGARY_IOMMU_ENABLED_BY_DEFAULT 916 def_bool y 917 prompt "Should Calgary be enabled by default?" 918 depends on CALGARY_IOMMU 919 ---help--- 920 Should Calgary be enabled by default? if you choose 'y', Calgary 921 will be used (if it exists). If you choose 'n', Calgary will not be 922 used even if it exists. If you choose 'n' and would like to use 923 Calgary anyway, pass 'iommu=calgary' on the kernel command line. 924 If unsure, say Y. 925 926# need this always selected by IOMMU for the VIA workaround 927config SWIOTLB 928 def_bool y if X86_64 929 ---help--- 930 Support for software bounce buffers used on x86-64 systems 931 which don't have a hardware IOMMU. Using this PCI devices 932 which can only access 32-bits of memory can be used on systems 933 with more than 3 GB of memory. 934 If unsure, say Y. 935 936config IOMMU_HELPER 937 def_bool y 938 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU 939 940config MAXSMP 941 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 942 depends on X86_64 && SMP && DEBUG_KERNEL 943 select CPUMASK_OFFSTACK 944 ---help--- 945 Enable maximum number of CPUS and NUMA Nodes for this architecture. 946 If unsure, say N. 947 948# 949# The maximum number of CPUs supported: 950# 951# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 952# and which can be configured interactively in the 953# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 954# 955# The ranges are different on 32-bit and 64-bit kernels, depending on 956# hardware capabilities and scalability features of the kernel. 957# 958# ( If MAXSMP is enabled we just use the highest possible value and disable 959# interactive configuration. ) 960# 961 962config NR_CPUS_RANGE_BEGIN 963 int 964 default NR_CPUS_RANGE_END if MAXSMP 965 default 1 if !SMP 966 default 2 967 968config NR_CPUS_RANGE_END 969 int 970 depends on X86_32 971 default 64 if SMP && X86_BIGSMP 972 default 8 if SMP && !X86_BIGSMP 973 default 1 if !SMP 974 975config NR_CPUS_RANGE_END 976 int 977 depends on X86_64 978 default 8192 if SMP && ( MAXSMP || CPUMASK_OFFSTACK) 979 default 512 if SMP && (!MAXSMP && !CPUMASK_OFFSTACK) 980 default 1 if !SMP 981 982config NR_CPUS_DEFAULT 983 int 984 depends on X86_32 985 default 32 if X86_BIGSMP 986 default 8 if SMP 987 default 1 if !SMP 988 989config NR_CPUS_DEFAULT 990 int 991 depends on X86_64 992 default 8192 if MAXSMP 993 default 64 if SMP 994 default 1 if !SMP 995 996config NR_CPUS 997 int "Maximum number of CPUs" if SMP && !MAXSMP 998 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 999 default NR_CPUS_DEFAULT 1000 ---help--- 1001 This allows you to specify the maximum number of CPUs which this 1002 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1003 supported value is 8192, otherwise the maximum value is 512. The 1004 minimum value which makes sense is 2. 1005 1006 This is purely to save memory: each supported CPU adds about 8KB 1007 to the kernel image. 1008 1009config SCHED_SMT 1010 bool "SMT (Hyperthreading) scheduler support" 1011 depends on SMP 1012 ---help--- 1013 SMT scheduler support improves the CPU scheduler's decision making 1014 when dealing with Intel Pentium 4 chips with HyperThreading at a 1015 cost of slightly increased overhead in some places. If unsure say 1016 N here. 1017 1018config SCHED_MC 1019 def_bool y 1020 prompt "Multi-core scheduler support" 1021 depends on SMP 1022 ---help--- 1023 Multi-core scheduler support improves the CPU scheduler's decision 1024 making when dealing with multi-core CPU chips at a cost of slightly 1025 increased overhead in some places. If unsure say N here. 1026 1027config SCHED_MC_PRIO 1028 bool "CPU core priorities scheduler support" 1029 depends on SCHED_MC && CPU_SUP_INTEL 1030 select X86_INTEL_PSTATE 1031 select CPU_FREQ 1032 default y 1033 ---help--- 1034 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1035 core ordering determined at manufacturing time, which allows 1036 certain cores to reach higher turbo frequencies (when running 1037 single threaded workloads) than others. 1038 1039 Enabling this kernel feature teaches the scheduler about 1040 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1041 scheduler's CPU selection logic accordingly, so that higher 1042 overall system performance can be achieved. 1043 1044 This feature will have no effect on CPUs without this feature. 1045 1046 If unsure say Y here. 1047 1048source "kernel/Kconfig.preempt" 1049 1050config UP_LATE_INIT 1051 def_bool y 1052 depends on !SMP && X86_LOCAL_APIC 1053 1054config X86_UP_APIC 1055 bool "Local APIC support on uniprocessors" if !PCI_MSI 1056 default PCI_MSI 1057 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1058 ---help--- 1059 A local APIC (Advanced Programmable Interrupt Controller) is an 1060 integrated interrupt controller in the CPU. If you have a single-CPU 1061 system which has a processor with a local APIC, you can say Y here to 1062 enable and use it. If you say Y here even though your machine doesn't 1063 have a local APIC, then the kernel will still run with no slowdown at 1064 all. The local APIC supports CPU-generated self-interrupts (timer, 1065 performance counters), and the NMI watchdog which detects hard 1066 lockups. 1067 1068config X86_UP_IOAPIC 1069 bool "IO-APIC support on uniprocessors" 1070 depends on X86_UP_APIC 1071 ---help--- 1072 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1073 SMP-capable replacement for PC-style interrupt controllers. Most 1074 SMP systems and many recent uniprocessor systems have one. 1075 1076 If you have a single-CPU system with an IO-APIC, you can say Y here 1077 to use it. If you say Y here even though your machine doesn't have 1078 an IO-APIC, then the kernel will still run with no slowdown at all. 1079 1080config X86_LOCAL_APIC 1081 def_bool y 1082 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1083 select IRQ_DOMAIN_HIERARCHY 1084 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1085 1086config X86_IO_APIC 1087 def_bool y 1088 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1089 1090config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1091 bool "Reroute for broken boot IRQs" 1092 depends on X86_IO_APIC 1093 ---help--- 1094 This option enables a workaround that fixes a source of 1095 spurious interrupts. This is recommended when threaded 1096 interrupt handling is used on systems where the generation of 1097 superfluous "boot interrupts" cannot be disabled. 1098 1099 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1100 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1101 kernel does during interrupt handling). On chipsets where this 1102 boot IRQ generation cannot be disabled, this workaround keeps 1103 the original IRQ line masked so that only the equivalent "boot 1104 IRQ" is delivered to the CPUs. The workaround also tells the 1105 kernel to set up the IRQ handler on the boot IRQ line. In this 1106 way only one interrupt is delivered to the kernel. Otherwise 1107 the spurious second interrupt may cause the kernel to bring 1108 down (vital) interrupt lines. 1109 1110 Only affects "broken" chipsets. Interrupt sharing may be 1111 increased on these systems. 1112 1113config X86_MCE 1114 bool "Machine Check / overheating reporting" 1115 select GENERIC_ALLOCATOR 1116 default y 1117 ---help--- 1118 Machine Check support allows the processor to notify the 1119 kernel if it detects a problem (e.g. overheating, data corruption). 1120 The action the kernel takes depends on the severity of the problem, 1121 ranging from warning messages to halting the machine. 1122 1123config X86_MCELOG_LEGACY 1124 bool "Support for deprecated /dev/mcelog character device" 1125 depends on X86_MCE 1126 ---help--- 1127 Enable support for /dev/mcelog which is needed by the old mcelog 1128 userspace logging daemon. Consider switching to the new generation 1129 rasdaemon solution. 1130 1131config X86_MCE_INTEL 1132 def_bool y 1133 prompt "Intel MCE features" 1134 depends on X86_MCE && X86_LOCAL_APIC 1135 ---help--- 1136 Additional support for intel specific MCE features such as 1137 the thermal monitor. 1138 1139config X86_MCE_AMD 1140 def_bool y 1141 prompt "AMD MCE features" 1142 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1143 ---help--- 1144 Additional support for AMD specific MCE features such as 1145 the DRAM Error Threshold. 1146 1147config X86_ANCIENT_MCE 1148 bool "Support for old Pentium 5 / WinChip machine checks" 1149 depends on X86_32 && X86_MCE 1150 ---help--- 1151 Include support for machine check handling on old Pentium 5 or WinChip 1152 systems. These typically need to be enabled explicitly on the command 1153 line. 1154 1155config X86_MCE_THRESHOLD 1156 depends on X86_MCE_AMD || X86_MCE_INTEL 1157 def_bool y 1158 1159config X86_MCE_INJECT 1160 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1161 tristate "Machine check injector support" 1162 ---help--- 1163 Provide support for injecting machine checks for testing purposes. 1164 If you don't know what a machine check is and you don't do kernel 1165 QA it is safe to say n. 1166 1167config X86_THERMAL_VECTOR 1168 def_bool y 1169 depends on X86_MCE_INTEL 1170 1171source "arch/x86/events/Kconfig" 1172 1173config X86_LEGACY_VM86 1174 bool "Legacy VM86 support" 1175 default n 1176 depends on X86_32 1177 ---help--- 1178 This option allows user programs to put the CPU into V8086 1179 mode, which is an 80286-era approximation of 16-bit real mode. 1180 1181 Some very old versions of X and/or vbetool require this option 1182 for user mode setting. Similarly, DOSEMU will use it if 1183 available to accelerate real mode DOS programs. However, any 1184 recent version of DOSEMU, X, or vbetool should be fully 1185 functional even without kernel VM86 support, as they will all 1186 fall back to software emulation. Nevertheless, if you are using 1187 a 16-bit DOS program where 16-bit performance matters, vm86 1188 mode might be faster than emulation and you might want to 1189 enable this option. 1190 1191 Note that any app that works on a 64-bit kernel is unlikely to 1192 need this option, as 64-bit kernels don't, and can't, support 1193 V8086 mode. This option is also unrelated to 16-bit protected 1194 mode and is not needed to run most 16-bit programs under Wine. 1195 1196 Enabling this option increases the complexity of the kernel 1197 and slows down exception handling a tiny bit. 1198 1199 If unsure, say N here. 1200 1201config VM86 1202 bool 1203 default X86_LEGACY_VM86 1204 1205config X86_16BIT 1206 bool "Enable support for 16-bit segments" if EXPERT 1207 default y 1208 depends on MODIFY_LDT_SYSCALL 1209 ---help--- 1210 This option is required by programs like Wine to run 16-bit 1211 protected mode legacy code on x86 processors. Disabling 1212 this option saves about 300 bytes on i386, or around 6K text 1213 plus 16K runtime memory on x86-64, 1214 1215config X86_ESPFIX32 1216 def_bool y 1217 depends on X86_16BIT && X86_32 1218 1219config X86_ESPFIX64 1220 def_bool y 1221 depends on X86_16BIT && X86_64 1222 1223config X86_VSYSCALL_EMULATION 1224 bool "Enable vsyscall emulation" if EXPERT 1225 default y 1226 depends on X86_64 1227 ---help--- 1228 This enables emulation of the legacy vsyscall page. Disabling 1229 it is roughly equivalent to booting with vsyscall=none, except 1230 that it will also disable the helpful warning if a program 1231 tries to use a vsyscall. With this option set to N, offending 1232 programs will just segfault, citing addresses of the form 1233 0xffffffffff600?00. 1234 1235 This option is required by many programs built before 2013, and 1236 care should be used even with newer programs if set to N. 1237 1238 Disabling this option saves about 7K of kernel size and 1239 possibly 4K of additional runtime pagetable memory. 1240 1241config TOSHIBA 1242 tristate "Toshiba Laptop support" 1243 depends on X86_32 1244 ---help--- 1245 This adds a driver to safely access the System Management Mode of 1246 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1247 not work on models with a Phoenix BIOS. The System Management Mode 1248 is used to set the BIOS and power saving options on Toshiba portables. 1249 1250 For information on utilities to make use of this driver see the 1251 Toshiba Linux utilities web site at: 1252 <http://www.buzzard.org.uk/toshiba/>. 1253 1254 Say Y if you intend to run this kernel on a Toshiba portable. 1255 Say N otherwise. 1256 1257config I8K 1258 tristate "Dell i8k legacy laptop support" 1259 select HWMON 1260 select SENSORS_DELL_SMM 1261 ---help--- 1262 This option enables legacy /proc/i8k userspace interface in hwmon 1263 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1264 temperature and allows controlling fan speeds of Dell laptops via 1265 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1266 it reports also power and hotkey status. For fan speed control is 1267 needed userspace package i8kutils. 1268 1269 Say Y if you intend to run this kernel on old Dell laptops or want to 1270 use userspace package i8kutils. 1271 Say N otherwise. 1272 1273config X86_REBOOTFIXUPS 1274 bool "Enable X86 board specific fixups for reboot" 1275 depends on X86_32 1276 ---help--- 1277 This enables chipset and/or board specific fixups to be done 1278 in order to get reboot to work correctly. This is only needed on 1279 some combinations of hardware and BIOS. The symptom, for which 1280 this config is intended, is when reboot ends with a stalled/hung 1281 system. 1282 1283 Currently, the only fixup is for the Geode machines using 1284 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1285 1286 Say Y if you want to enable the fixup. Currently, it's safe to 1287 enable this option even if you don't need it. 1288 Say N otherwise. 1289 1290config MICROCODE 1291 bool "CPU microcode loading support" 1292 default y 1293 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1294 select FW_LOADER 1295 ---help--- 1296 If you say Y here, you will be able to update the microcode on 1297 Intel and AMD processors. The Intel support is for the IA32 family, 1298 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1299 AMD support is for families 0x10 and later. You will obviously need 1300 the actual microcode binary data itself which is not shipped with 1301 the Linux kernel. 1302 1303 The preferred method to load microcode from a detached initrd is described 1304 in Documentation/x86/microcode.txt. For that you need to enable 1305 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1306 initrd for microcode blobs. 1307 1308 In addition, you can build the microcode into the kernel. For that you 1309 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1310 config option. 1311 1312config MICROCODE_INTEL 1313 bool "Intel microcode loading support" 1314 depends on MICROCODE 1315 default MICROCODE 1316 select FW_LOADER 1317 ---help--- 1318 This options enables microcode patch loading support for Intel 1319 processors. 1320 1321 For the current Intel microcode data package go to 1322 <https://downloadcenter.intel.com> and search for 1323 'Linux Processor Microcode Data File'. 1324 1325config MICROCODE_AMD 1326 bool "AMD microcode loading support" 1327 depends on MICROCODE 1328 select FW_LOADER 1329 ---help--- 1330 If you select this option, microcode patch loading support for AMD 1331 processors will be enabled. 1332 1333config MICROCODE_OLD_INTERFACE 1334 def_bool y 1335 depends on MICROCODE 1336 1337config X86_MSR 1338 tristate "/dev/cpu/*/msr - Model-specific register support" 1339 ---help--- 1340 This device gives privileged processes access to the x86 1341 Model-Specific Registers (MSRs). It is a character device with 1342 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1343 MSR accesses are directed to a specific CPU on multi-processor 1344 systems. 1345 1346config X86_CPUID 1347 tristate "/dev/cpu/*/cpuid - CPU information support" 1348 ---help--- 1349 This device gives processes access to the x86 CPUID instruction to 1350 be executed on a specific processor. It is a character device 1351 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1352 /dev/cpu/31/cpuid. 1353 1354choice 1355 prompt "High Memory Support" 1356 default HIGHMEM4G 1357 depends on X86_32 1358 1359config NOHIGHMEM 1360 bool "off" 1361 ---help--- 1362 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1363 However, the address space of 32-bit x86 processors is only 4 1364 Gigabytes large. That means that, if you have a large amount of 1365 physical memory, not all of it can be "permanently mapped" by the 1366 kernel. The physical memory that's not permanently mapped is called 1367 "high memory". 1368 1369 If you are compiling a kernel which will never run on a machine with 1370 more than 1 Gigabyte total physical RAM, answer "off" here (default 1371 choice and suitable for most users). This will result in a "3GB/1GB" 1372 split: 3GB are mapped so that each process sees a 3GB virtual memory 1373 space and the remaining part of the 4GB virtual memory space is used 1374 by the kernel to permanently map as much physical memory as 1375 possible. 1376 1377 If the machine has between 1 and 4 Gigabytes physical RAM, then 1378 answer "4GB" here. 1379 1380 If more than 4 Gigabytes is used then answer "64GB" here. This 1381 selection turns Intel PAE (Physical Address Extension) mode on. 1382 PAE implements 3-level paging on IA32 processors. PAE is fully 1383 supported by Linux, PAE mode is implemented on all recent Intel 1384 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1385 then the kernel will not boot on CPUs that don't support PAE! 1386 1387 The actual amount of total physical memory will either be 1388 auto detected or can be forced by using a kernel command line option 1389 such as "mem=256M". (Try "man bootparam" or see the documentation of 1390 your boot loader (lilo or loadlin) about how to pass options to the 1391 kernel at boot time.) 1392 1393 If unsure, say "off". 1394 1395config HIGHMEM4G 1396 bool "4GB" 1397 ---help--- 1398 Select this if you have a 32-bit processor and between 1 and 4 1399 gigabytes of physical RAM. 1400 1401config HIGHMEM64G 1402 bool "64GB" 1403 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1404 select X86_PAE 1405 ---help--- 1406 Select this if you have a 32-bit processor and more than 4 1407 gigabytes of physical RAM. 1408 1409endchoice 1410 1411choice 1412 prompt "Memory split" if EXPERT 1413 default VMSPLIT_3G 1414 depends on X86_32 1415 ---help--- 1416 Select the desired split between kernel and user memory. 1417 1418 If the address range available to the kernel is less than the 1419 physical memory installed, the remaining memory will be available 1420 as "high memory". Accessing high memory is a little more costly 1421 than low memory, as it needs to be mapped into the kernel first. 1422 Note that increasing the kernel address space limits the range 1423 available to user programs, making the address space there 1424 tighter. Selecting anything other than the default 3G/1G split 1425 will also likely make your kernel incompatible with binary-only 1426 kernel modules. 1427 1428 If you are not absolutely sure what you are doing, leave this 1429 option alone! 1430 1431 config VMSPLIT_3G 1432 bool "3G/1G user/kernel split" 1433 config VMSPLIT_3G_OPT 1434 depends on !X86_PAE 1435 bool "3G/1G user/kernel split (for full 1G low memory)" 1436 config VMSPLIT_2G 1437 bool "2G/2G user/kernel split" 1438 config VMSPLIT_2G_OPT 1439 depends on !X86_PAE 1440 bool "2G/2G user/kernel split (for full 2G low memory)" 1441 config VMSPLIT_1G 1442 bool "1G/3G user/kernel split" 1443endchoice 1444 1445config PAGE_OFFSET 1446 hex 1447 default 0xB0000000 if VMSPLIT_3G_OPT 1448 default 0x80000000 if VMSPLIT_2G 1449 default 0x78000000 if VMSPLIT_2G_OPT 1450 default 0x40000000 if VMSPLIT_1G 1451 default 0xC0000000 1452 depends on X86_32 1453 1454config HIGHMEM 1455 def_bool y 1456 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1457 1458config X86_PAE 1459 bool "PAE (Physical Address Extension) Support" 1460 depends on X86_32 && !HIGHMEM4G 1461 select SWIOTLB 1462 ---help--- 1463 PAE is required for NX support, and furthermore enables 1464 larger swapspace support for non-overcommit purposes. It 1465 has the cost of more pagetable lookup overhead, and also 1466 consumes more pagetable space per process. 1467 1468config X86_5LEVEL 1469 bool "Enable 5-level page tables support" 1470 select DYNAMIC_MEMORY_LAYOUT 1471 select SPARSEMEM_VMEMMAP 1472 depends on X86_64 1473 ---help--- 1474 5-level paging enables access to larger address space: 1475 upto 128 PiB of virtual address space and 4 PiB of 1476 physical address space. 1477 1478 It will be supported by future Intel CPUs. 1479 1480 A kernel with the option enabled can be booted on machines that 1481 support 4- or 5-level paging. 1482 1483 See Documentation/x86/x86_64/5level-paging.txt for more 1484 information. 1485 1486 Say N if unsure. 1487 1488config ARCH_PHYS_ADDR_T_64BIT 1489 def_bool y 1490 depends on X86_64 || X86_PAE 1491 1492config ARCH_DMA_ADDR_T_64BIT 1493 def_bool y 1494 depends on X86_64 || HIGHMEM64G 1495 1496config X86_DIRECT_GBPAGES 1497 def_bool y 1498 depends on X86_64 && !DEBUG_PAGEALLOC 1499 ---help--- 1500 Certain kernel features effectively disable kernel 1501 linear 1 GB mappings (even if the CPU otherwise 1502 supports them), so don't confuse the user by printing 1503 that we have them enabled. 1504 1505config ARCH_HAS_MEM_ENCRYPT 1506 def_bool y 1507 1508config AMD_MEM_ENCRYPT 1509 bool "AMD Secure Memory Encryption (SME) support" 1510 depends on X86_64 && CPU_SUP_AMD 1511 ---help--- 1512 Say yes to enable support for the encryption of system memory. 1513 This requires an AMD processor that supports Secure Memory 1514 Encryption (SME). 1515 1516config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1517 bool "Activate AMD Secure Memory Encryption (SME) by default" 1518 default y 1519 depends on AMD_MEM_ENCRYPT 1520 ---help--- 1521 Say yes to have system memory encrypted by default if running on 1522 an AMD processor that supports Secure Memory Encryption (SME). 1523 1524 If set to Y, then the encryption of system memory can be 1525 deactivated with the mem_encrypt=off command line option. 1526 1527 If set to N, then the encryption of system memory can be 1528 activated with the mem_encrypt=on command line option. 1529 1530config ARCH_USE_MEMREMAP_PROT 1531 def_bool y 1532 depends on AMD_MEM_ENCRYPT 1533 1534# Common NUMA Features 1535config NUMA 1536 bool "Numa Memory Allocation and Scheduler Support" 1537 depends on SMP 1538 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1539 default y if X86_BIGSMP 1540 ---help--- 1541 Enable NUMA (Non Uniform Memory Access) support. 1542 1543 The kernel will try to allocate memory used by a CPU on the 1544 local memory controller of the CPU and add some more 1545 NUMA awareness to the kernel. 1546 1547 For 64-bit this is recommended if the system is Intel Core i7 1548 (or later), AMD Opteron, or EM64T NUMA. 1549 1550 For 32-bit this is only needed if you boot a 32-bit 1551 kernel on a 64-bit NUMA platform. 1552 1553 Otherwise, you should say N. 1554 1555config AMD_NUMA 1556 def_bool y 1557 prompt "Old style AMD Opteron NUMA detection" 1558 depends on X86_64 && NUMA && PCI 1559 ---help--- 1560 Enable AMD NUMA node topology detection. You should say Y here if 1561 you have a multi processor AMD system. This uses an old method to 1562 read the NUMA configuration directly from the builtin Northbridge 1563 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1564 which also takes priority if both are compiled in. 1565 1566config X86_64_ACPI_NUMA 1567 def_bool y 1568 prompt "ACPI NUMA detection" 1569 depends on X86_64 && NUMA && ACPI && PCI 1570 select ACPI_NUMA 1571 ---help--- 1572 Enable ACPI SRAT based node topology detection. 1573 1574# Some NUMA nodes have memory ranges that span 1575# other nodes. Even though a pfn is valid and 1576# between a node's start and end pfns, it may not 1577# reside on that node. See memmap_init_zone() 1578# for details. 1579config NODES_SPAN_OTHER_NODES 1580 def_bool y 1581 depends on X86_64_ACPI_NUMA 1582 1583config NUMA_EMU 1584 bool "NUMA emulation" 1585 depends on NUMA 1586 ---help--- 1587 Enable NUMA emulation. A flat machine will be split 1588 into virtual nodes when booted with "numa=fake=N", where N is the 1589 number of nodes. This is only useful for debugging. 1590 1591config NODES_SHIFT 1592 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1593 range 1 10 1594 default "10" if MAXSMP 1595 default "6" if X86_64 1596 default "3" 1597 depends on NEED_MULTIPLE_NODES 1598 ---help--- 1599 Specify the maximum number of NUMA Nodes available on the target 1600 system. Increases memory reserved to accommodate various tables. 1601 1602config ARCH_HAVE_MEMORY_PRESENT 1603 def_bool y 1604 depends on X86_32 && DISCONTIGMEM 1605 1606config ARCH_FLATMEM_ENABLE 1607 def_bool y 1608 depends on X86_32 && !NUMA 1609 1610config ARCH_DISCONTIGMEM_ENABLE 1611 def_bool y 1612 depends on NUMA && X86_32 1613 1614config ARCH_DISCONTIGMEM_DEFAULT 1615 def_bool y 1616 depends on NUMA && X86_32 1617 1618config ARCH_SPARSEMEM_ENABLE 1619 def_bool y 1620 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1621 select SPARSEMEM_STATIC if X86_32 1622 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1623 1624config ARCH_SPARSEMEM_DEFAULT 1625 def_bool y 1626 depends on X86_64 1627 1628config ARCH_SELECT_MEMORY_MODEL 1629 def_bool y 1630 depends on ARCH_SPARSEMEM_ENABLE 1631 1632config ARCH_MEMORY_PROBE 1633 bool "Enable sysfs memory/probe interface" 1634 depends on X86_64 && MEMORY_HOTPLUG 1635 help 1636 This option enables a sysfs memory/probe interface for testing. 1637 See Documentation/memory-hotplug.txt for more information. 1638 If you are unsure how to answer this question, answer N. 1639 1640config ARCH_PROC_KCORE_TEXT 1641 def_bool y 1642 depends on X86_64 && PROC_KCORE 1643 1644config ILLEGAL_POINTER_VALUE 1645 hex 1646 default 0 if X86_32 1647 default 0xdead000000000000 if X86_64 1648 1649source "mm/Kconfig" 1650 1651config X86_PMEM_LEGACY_DEVICE 1652 bool 1653 1654config X86_PMEM_LEGACY 1655 tristate "Support non-standard NVDIMMs and ADR protected memory" 1656 depends on PHYS_ADDR_T_64BIT 1657 depends on BLK_DEV 1658 select X86_PMEM_LEGACY_DEVICE 1659 select LIBNVDIMM 1660 help 1661 Treat memory marked using the non-standard e820 type of 12 as used 1662 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1663 The kernel will offer these regions to the 'pmem' driver so 1664 they can be used for persistent storage. 1665 1666 Say Y if unsure. 1667 1668config HIGHPTE 1669 bool "Allocate 3rd-level pagetables from highmem" 1670 depends on HIGHMEM 1671 ---help--- 1672 The VM uses one page table entry for each page of physical memory. 1673 For systems with a lot of RAM, this can be wasteful of precious 1674 low memory. Setting this option will put user-space page table 1675 entries in high memory. 1676 1677config X86_CHECK_BIOS_CORRUPTION 1678 bool "Check for low memory corruption" 1679 ---help--- 1680 Periodically check for memory corruption in low memory, which 1681 is suspected to be caused by BIOS. Even when enabled in the 1682 configuration, it is disabled at runtime. Enable it by 1683 setting "memory_corruption_check=1" on the kernel command 1684 line. By default it scans the low 64k of memory every 60 1685 seconds; see the memory_corruption_check_size and 1686 memory_corruption_check_period parameters in 1687 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1688 1689 When enabled with the default parameters, this option has 1690 almost no overhead, as it reserves a relatively small amount 1691 of memory and scans it infrequently. It both detects corruption 1692 and prevents it from affecting the running system. 1693 1694 It is, however, intended as a diagnostic tool; if repeatable 1695 BIOS-originated corruption always affects the same memory, 1696 you can use memmap= to prevent the kernel from using that 1697 memory. 1698 1699config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1700 bool "Set the default setting of memory_corruption_check" 1701 depends on X86_CHECK_BIOS_CORRUPTION 1702 default y 1703 ---help--- 1704 Set whether the default state of memory_corruption_check is 1705 on or off. 1706 1707config X86_RESERVE_LOW 1708 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1709 default 64 1710 range 4 640 1711 ---help--- 1712 Specify the amount of low memory to reserve for the BIOS. 1713 1714 The first page contains BIOS data structures that the kernel 1715 must not use, so that page must always be reserved. 1716 1717 By default we reserve the first 64K of physical RAM, as a 1718 number of BIOSes are known to corrupt that memory range 1719 during events such as suspend/resume or monitor cable 1720 insertion, so it must not be used by the kernel. 1721 1722 You can set this to 4 if you are absolutely sure that you 1723 trust the BIOS to get all its memory reservations and usages 1724 right. If you know your BIOS have problems beyond the 1725 default 64K area, you can set this to 640 to avoid using the 1726 entire low memory range. 1727 1728 If you have doubts about the BIOS (e.g. suspend/resume does 1729 not work or there's kernel crashes after certain hardware 1730 hotplug events) then you might want to enable 1731 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1732 typical corruption patterns. 1733 1734 Leave this to the default value of 64 if you are unsure. 1735 1736config MATH_EMULATION 1737 bool 1738 depends on MODIFY_LDT_SYSCALL 1739 prompt "Math emulation" if X86_32 1740 ---help--- 1741 Linux can emulate a math coprocessor (used for floating point 1742 operations) if you don't have one. 486DX and Pentium processors have 1743 a math coprocessor built in, 486SX and 386 do not, unless you added 1744 a 487DX or 387, respectively. (The messages during boot time can 1745 give you some hints here ["man dmesg"].) Everyone needs either a 1746 coprocessor or this emulation. 1747 1748 If you don't have a math coprocessor, you need to say Y here; if you 1749 say Y here even though you have a coprocessor, the coprocessor will 1750 be used nevertheless. (This behavior can be changed with the kernel 1751 command line option "no387", which comes handy if your coprocessor 1752 is broken. Try "man bootparam" or see the documentation of your boot 1753 loader (lilo or loadlin) about how to pass options to the kernel at 1754 boot time.) This means that it is a good idea to say Y here if you 1755 intend to use this kernel on different machines. 1756 1757 More information about the internals of the Linux math coprocessor 1758 emulation can be found in <file:arch/x86/math-emu/README>. 1759 1760 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1761 kernel, it won't hurt. 1762 1763config MTRR 1764 def_bool y 1765 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1766 ---help--- 1767 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1768 the Memory Type Range Registers (MTRRs) may be used to control 1769 processor access to memory ranges. This is most useful if you have 1770 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1771 allows bus write transfers to be combined into a larger transfer 1772 before bursting over the PCI/AGP bus. This can increase performance 1773 of image write operations 2.5 times or more. Saying Y here creates a 1774 /proc/mtrr file which may be used to manipulate your processor's 1775 MTRRs. Typically the X server should use this. 1776 1777 This code has a reasonably generic interface so that similar 1778 control registers on other processors can be easily supported 1779 as well: 1780 1781 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1782 Registers (ARRs) which provide a similar functionality to MTRRs. For 1783 these, the ARRs are used to emulate the MTRRs. 1784 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1785 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1786 write-combining. All of these processors are supported by this code 1787 and it makes sense to say Y here if you have one of them. 1788 1789 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1790 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1791 can lead to all sorts of problems, so it's good to say Y here. 1792 1793 You can safely say Y even if your machine doesn't have MTRRs, you'll 1794 just add about 9 KB to your kernel. 1795 1796 See <file:Documentation/x86/mtrr.txt> for more information. 1797 1798config MTRR_SANITIZER 1799 def_bool y 1800 prompt "MTRR cleanup support" 1801 depends on MTRR 1802 ---help--- 1803 Convert MTRR layout from continuous to discrete, so X drivers can 1804 add writeback entries. 1805 1806 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1807 The largest mtrr entry size for a continuous block can be set with 1808 mtrr_chunk_size. 1809 1810 If unsure, say Y. 1811 1812config MTRR_SANITIZER_ENABLE_DEFAULT 1813 int "MTRR cleanup enable value (0-1)" 1814 range 0 1 1815 default "0" 1816 depends on MTRR_SANITIZER 1817 ---help--- 1818 Enable mtrr cleanup default value 1819 1820config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1821 int "MTRR cleanup spare reg num (0-7)" 1822 range 0 7 1823 default "1" 1824 depends on MTRR_SANITIZER 1825 ---help--- 1826 mtrr cleanup spare entries default, it can be changed via 1827 mtrr_spare_reg_nr=N on the kernel command line. 1828 1829config X86_PAT 1830 def_bool y 1831 prompt "x86 PAT support" if EXPERT 1832 depends on MTRR 1833 ---help--- 1834 Use PAT attributes to setup page level cache control. 1835 1836 PATs are the modern equivalents of MTRRs and are much more 1837 flexible than MTRRs. 1838 1839 Say N here if you see bootup problems (boot crash, boot hang, 1840 spontaneous reboots) or a non-working video driver. 1841 1842 If unsure, say Y. 1843 1844config ARCH_USES_PG_UNCACHED 1845 def_bool y 1846 depends on X86_PAT 1847 1848config ARCH_RANDOM 1849 def_bool y 1850 prompt "x86 architectural random number generator" if EXPERT 1851 ---help--- 1852 Enable the x86 architectural RDRAND instruction 1853 (Intel Bull Mountain technology) to generate random numbers. 1854 If supported, this is a high bandwidth, cryptographically 1855 secure hardware random number generator. 1856 1857config X86_SMAP 1858 def_bool y 1859 prompt "Supervisor Mode Access Prevention" if EXPERT 1860 ---help--- 1861 Supervisor Mode Access Prevention (SMAP) is a security 1862 feature in newer Intel processors. There is a small 1863 performance cost if this enabled and turned on; there is 1864 also a small increase in the kernel size if this is enabled. 1865 1866 If unsure, say Y. 1867 1868config X86_INTEL_UMIP 1869 def_bool y 1870 depends on CPU_SUP_INTEL 1871 prompt "Intel User Mode Instruction Prevention" if EXPERT 1872 ---help--- 1873 The User Mode Instruction Prevention (UMIP) is a security 1874 feature in newer Intel processors. If enabled, a general 1875 protection fault is issued if the SGDT, SLDT, SIDT, SMSW 1876 or STR instructions are executed in user mode. These instructions 1877 unnecessarily expose information about the hardware state. 1878 1879 The vast majority of applications do not use these instructions. 1880 For the very few that do, software emulation is provided in 1881 specific cases in protected and virtual-8086 modes. Emulated 1882 results are dummy. 1883 1884config X86_INTEL_MPX 1885 prompt "Intel MPX (Memory Protection Extensions)" 1886 def_bool n 1887 # Note: only available in 64-bit mode due to VMA flags shortage 1888 depends on CPU_SUP_INTEL && X86_64 1889 select ARCH_USES_HIGH_VMA_FLAGS 1890 ---help--- 1891 MPX provides hardware features that can be used in 1892 conjunction with compiler-instrumented code to check 1893 memory references. It is designed to detect buffer 1894 overflow or underflow bugs. 1895 1896 This option enables running applications which are 1897 instrumented or otherwise use MPX. It does not use MPX 1898 itself inside the kernel or to protect the kernel 1899 against bad memory references. 1900 1901 Enabling this option will make the kernel larger: 1902 ~8k of kernel text and 36 bytes of data on a 64-bit 1903 defconfig. It adds a long to the 'mm_struct' which 1904 will increase the kernel memory overhead of each 1905 process and adds some branches to paths used during 1906 exec() and munmap(). 1907 1908 For details, see Documentation/x86/intel_mpx.txt 1909 1910 If unsure, say N. 1911 1912config X86_INTEL_MEMORY_PROTECTION_KEYS 1913 prompt "Intel Memory Protection Keys" 1914 def_bool y 1915 # Note: only available in 64-bit mode 1916 depends on CPU_SUP_INTEL && X86_64 1917 select ARCH_USES_HIGH_VMA_FLAGS 1918 select ARCH_HAS_PKEYS 1919 ---help--- 1920 Memory Protection Keys provides a mechanism for enforcing 1921 page-based protections, but without requiring modification of the 1922 page tables when an application changes protection domains. 1923 1924 For details, see Documentation/x86/protection-keys.txt 1925 1926 If unsure, say y. 1927 1928config EFI 1929 bool "EFI runtime service support" 1930 depends on ACPI 1931 select UCS2_STRING 1932 select EFI_RUNTIME_WRAPPERS 1933 ---help--- 1934 This enables the kernel to use EFI runtime services that are 1935 available (such as the EFI variable services). 1936 1937 This option is only useful on systems that have EFI firmware. 1938 In addition, you should use the latest ELILO loader available 1939 at <http://elilo.sourceforge.net> in order to take advantage 1940 of EFI runtime services. However, even with this option, the 1941 resultant kernel should continue to boot on existing non-EFI 1942 platforms. 1943 1944config EFI_STUB 1945 bool "EFI stub support" 1946 depends on EFI && !X86_USE_3DNOW 1947 select RELOCATABLE 1948 ---help--- 1949 This kernel feature allows a bzImage to be loaded directly 1950 by EFI firmware without the use of a bootloader. 1951 1952 See Documentation/efi-stub.txt for more information. 1953 1954config EFI_MIXED 1955 bool "EFI mixed-mode support" 1956 depends on EFI_STUB && X86_64 1957 ---help--- 1958 Enabling this feature allows a 64-bit kernel to be booted 1959 on a 32-bit firmware, provided that your CPU supports 64-bit 1960 mode. 1961 1962 Note that it is not possible to boot a mixed-mode enabled 1963 kernel via the EFI boot stub - a bootloader that supports 1964 the EFI handover protocol must be used. 1965 1966 If unsure, say N. 1967 1968config SECCOMP 1969 def_bool y 1970 prompt "Enable seccomp to safely compute untrusted bytecode" 1971 ---help--- 1972 This kernel feature is useful for number crunching applications 1973 that may need to compute untrusted bytecode during their 1974 execution. By using pipes or other transports made available to 1975 the process as file descriptors supporting the read/write 1976 syscalls, it's possible to isolate those applications in 1977 their own address space using seccomp. Once seccomp is 1978 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 1979 and the task is only allowed to execute a few safe syscalls 1980 defined by each seccomp mode. 1981 1982 If unsure, say Y. Only embedded should say N here. 1983 1984source kernel/Kconfig.hz 1985 1986config KEXEC 1987 bool "kexec system call" 1988 select KEXEC_CORE 1989 ---help--- 1990 kexec is a system call that implements the ability to shutdown your 1991 current kernel, and to start another kernel. It is like a reboot 1992 but it is independent of the system firmware. And like a reboot 1993 you can start any kernel with it, not just Linux. 1994 1995 The name comes from the similarity to the exec system call. 1996 1997 It is an ongoing process to be certain the hardware in a machine 1998 is properly shutdown, so do not be surprised if this code does not 1999 initially work for you. As of this writing the exact hardware 2000 interface is strongly in flux, so no good recommendation can be 2001 made. 2002 2003config KEXEC_FILE 2004 bool "kexec file based system call" 2005 select KEXEC_CORE 2006 select BUILD_BIN2C 2007 depends on X86_64 2008 depends on CRYPTO=y 2009 depends on CRYPTO_SHA256=y 2010 ---help--- 2011 This is new version of kexec system call. This system call is 2012 file based and takes file descriptors as system call argument 2013 for kernel and initramfs as opposed to list of segments as 2014 accepted by previous system call. 2015 2016config ARCH_HAS_KEXEC_PURGATORY 2017 def_bool KEXEC_FILE 2018 2019config KEXEC_VERIFY_SIG 2020 bool "Verify kernel signature during kexec_file_load() syscall" 2021 depends on KEXEC_FILE 2022 ---help--- 2023 This option makes kernel signature verification mandatory for 2024 the kexec_file_load() syscall. 2025 2026 In addition to that option, you need to enable signature 2027 verification for the corresponding kernel image type being 2028 loaded in order for this to work. 2029 2030config KEXEC_BZIMAGE_VERIFY_SIG 2031 bool "Enable bzImage signature verification support" 2032 depends on KEXEC_VERIFY_SIG 2033 depends on SIGNED_PE_FILE_VERIFICATION 2034 select SYSTEM_TRUSTED_KEYRING 2035 ---help--- 2036 Enable bzImage signature verification support. 2037 2038config CRASH_DUMP 2039 bool "kernel crash dumps" 2040 depends on X86_64 || (X86_32 && HIGHMEM) 2041 ---help--- 2042 Generate crash dump after being started by kexec. 2043 This should be normally only set in special crash dump kernels 2044 which are loaded in the main kernel with kexec-tools into 2045 a specially reserved region and then later executed after 2046 a crash by kdump/kexec. The crash dump kernel must be compiled 2047 to a memory address not used by the main kernel or BIOS using 2048 PHYSICAL_START, or it must be built as a relocatable image 2049 (CONFIG_RELOCATABLE=y). 2050 For more details see Documentation/kdump/kdump.txt 2051 2052config KEXEC_JUMP 2053 bool "kexec jump" 2054 depends on KEXEC && HIBERNATION 2055 ---help--- 2056 Jump between original kernel and kexeced kernel and invoke 2057 code in physical address mode via KEXEC 2058 2059config PHYSICAL_START 2060 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2061 default "0x1000000" 2062 ---help--- 2063 This gives the physical address where the kernel is loaded. 2064 2065 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2066 bzImage will decompress itself to above physical address and 2067 run from there. Otherwise, bzImage will run from the address where 2068 it has been loaded by the boot loader and will ignore above physical 2069 address. 2070 2071 In normal kdump cases one does not have to set/change this option 2072 as now bzImage can be compiled as a completely relocatable image 2073 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2074 address. This option is mainly useful for the folks who don't want 2075 to use a bzImage for capturing the crash dump and want to use a 2076 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2077 to be specifically compiled to run from a specific memory area 2078 (normally a reserved region) and this option comes handy. 2079 2080 So if you are using bzImage for capturing the crash dump, 2081 leave the value here unchanged to 0x1000000 and set 2082 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2083 for capturing the crash dump change this value to start of 2084 the reserved region. In other words, it can be set based on 2085 the "X" value as specified in the "crashkernel=YM@XM" 2086 command line boot parameter passed to the panic-ed 2087 kernel. Please take a look at Documentation/kdump/kdump.txt 2088 for more details about crash dumps. 2089 2090 Usage of bzImage for capturing the crash dump is recommended as 2091 one does not have to build two kernels. Same kernel can be used 2092 as production kernel and capture kernel. Above option should have 2093 gone away after relocatable bzImage support is introduced. But it 2094 is present because there are users out there who continue to use 2095 vmlinux for dump capture. This option should go away down the 2096 line. 2097 2098 Don't change this unless you know what you are doing. 2099 2100config RELOCATABLE 2101 bool "Build a relocatable kernel" 2102 default y 2103 ---help--- 2104 This builds a kernel image that retains relocation information 2105 so it can be loaded someplace besides the default 1MB. 2106 The relocations tend to make the kernel binary about 10% larger, 2107 but are discarded at runtime. 2108 2109 One use is for the kexec on panic case where the recovery kernel 2110 must live at a different physical address than the primary 2111 kernel. 2112 2113 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2114 it has been loaded at and the compile time physical address 2115 (CONFIG_PHYSICAL_START) is used as the minimum location. 2116 2117config RANDOMIZE_BASE 2118 bool "Randomize the address of the kernel image (KASLR)" 2119 depends on RELOCATABLE 2120 default y 2121 ---help--- 2122 In support of Kernel Address Space Layout Randomization (KASLR), 2123 this randomizes the physical address at which the kernel image 2124 is decompressed and the virtual address where the kernel 2125 image is mapped, as a security feature that deters exploit 2126 attempts relying on knowledge of the location of kernel 2127 code internals. 2128 2129 On 64-bit, the kernel physical and virtual addresses are 2130 randomized separately. The physical address will be anywhere 2131 between 16MB and the top of physical memory (up to 64TB). The 2132 virtual address will be randomized from 16MB up to 1GB (9 bits 2133 of entropy). Note that this also reduces the memory space 2134 available to kernel modules from 1.5GB to 1GB. 2135 2136 On 32-bit, the kernel physical and virtual addresses are 2137 randomized together. They will be randomized from 16MB up to 2138 512MB (8 bits of entropy). 2139 2140 Entropy is generated using the RDRAND instruction if it is 2141 supported. If RDTSC is supported, its value is mixed into 2142 the entropy pool as well. If neither RDRAND nor RDTSC are 2143 supported, then entropy is read from the i8254 timer. The 2144 usable entropy is limited by the kernel being built using 2145 2GB addressing, and that PHYSICAL_ALIGN must be at a 2146 minimum of 2MB. As a result, only 10 bits of entropy are 2147 theoretically possible, but the implementations are further 2148 limited due to memory layouts. 2149 2150 If unsure, say Y. 2151 2152# Relocation on x86 needs some additional build support 2153config X86_NEED_RELOCS 2154 def_bool y 2155 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2156 2157config PHYSICAL_ALIGN 2158 hex "Alignment value to which kernel should be aligned" 2159 default "0x200000" 2160 range 0x2000 0x1000000 if X86_32 2161 range 0x200000 0x1000000 if X86_64 2162 ---help--- 2163 This value puts the alignment restrictions on physical address 2164 where kernel is loaded and run from. Kernel is compiled for an 2165 address which meets above alignment restriction. 2166 2167 If bootloader loads the kernel at a non-aligned address and 2168 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2169 address aligned to above value and run from there. 2170 2171 If bootloader loads the kernel at a non-aligned address and 2172 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2173 load address and decompress itself to the address it has been 2174 compiled for and run from there. The address for which kernel is 2175 compiled already meets above alignment restrictions. Hence the 2176 end result is that kernel runs from a physical address meeting 2177 above alignment restrictions. 2178 2179 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2180 this value must be a multiple of 0x200000. 2181 2182 Don't change this unless you know what you are doing. 2183 2184config DYNAMIC_MEMORY_LAYOUT 2185 bool 2186 ---help--- 2187 This option makes base addresses of vmalloc and vmemmap as well as 2188 __PAGE_OFFSET movable during boot. 2189 2190config RANDOMIZE_MEMORY 2191 bool "Randomize the kernel memory sections" 2192 depends on X86_64 2193 depends on RANDOMIZE_BASE 2194 select DYNAMIC_MEMORY_LAYOUT 2195 default RANDOMIZE_BASE 2196 ---help--- 2197 Randomizes the base virtual address of kernel memory sections 2198 (physical memory mapping, vmalloc & vmemmap). This security feature 2199 makes exploits relying on predictable memory locations less reliable. 2200 2201 The order of allocations remains unchanged. Entropy is generated in 2202 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2203 configuration have in average 30,000 different possible virtual 2204 addresses for each memory section. 2205 2206 If unsure, say Y. 2207 2208config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2209 hex "Physical memory mapping padding" if EXPERT 2210 depends on RANDOMIZE_MEMORY 2211 default "0xa" if MEMORY_HOTPLUG 2212 default "0x0" 2213 range 0x1 0x40 if MEMORY_HOTPLUG 2214 range 0x0 0x40 2215 ---help--- 2216 Define the padding in terabytes added to the existing physical 2217 memory size during kernel memory randomization. It is useful 2218 for memory hotplug support but reduces the entropy available for 2219 address randomization. 2220 2221 If unsure, leave at the default value. 2222 2223config HOTPLUG_CPU 2224 bool "Support for hot-pluggable CPUs" 2225 depends on SMP 2226 ---help--- 2227 Say Y here to allow turning CPUs off and on. CPUs can be 2228 controlled through /sys/devices/system/cpu. 2229 ( Note: power management support will enable this option 2230 automatically on SMP systems. ) 2231 Say N if you want to disable CPU hotplug. 2232 2233config BOOTPARAM_HOTPLUG_CPU0 2234 bool "Set default setting of cpu0_hotpluggable" 2235 default n 2236 depends on HOTPLUG_CPU 2237 ---help--- 2238 Set whether default state of cpu0_hotpluggable is on or off. 2239 2240 Say Y here to enable CPU0 hotplug by default. If this switch 2241 is turned on, there is no need to give cpu0_hotplug kernel 2242 parameter and the CPU0 hotplug feature is enabled by default. 2243 2244 Please note: there are two known CPU0 dependencies if you want 2245 to enable the CPU0 hotplug feature either by this switch or by 2246 cpu0_hotplug kernel parameter. 2247 2248 First, resume from hibernate or suspend always starts from CPU0. 2249 So hibernate and suspend are prevented if CPU0 is offline. 2250 2251 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2252 offline if any interrupt can not migrate out of CPU0. There may 2253 be other CPU0 dependencies. 2254 2255 Please make sure the dependencies are under your control before 2256 you enable this feature. 2257 2258 Say N if you don't want to enable CPU0 hotplug feature by default. 2259 You still can enable the CPU0 hotplug feature at boot by kernel 2260 parameter cpu0_hotplug. 2261 2262config DEBUG_HOTPLUG_CPU0 2263 def_bool n 2264 prompt "Debug CPU0 hotplug" 2265 depends on HOTPLUG_CPU 2266 ---help--- 2267 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2268 soon as possible and boots up userspace with CPU0 offlined. User 2269 can online CPU0 back after boot time. 2270 2271 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2272 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2273 compilation or giving cpu0_hotplug kernel parameter at boot. 2274 2275 If unsure, say N. 2276 2277config COMPAT_VDSO 2278 def_bool n 2279 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2280 depends on COMPAT_32 2281 ---help--- 2282 Certain buggy versions of glibc will crash if they are 2283 presented with a 32-bit vDSO that is not mapped at the address 2284 indicated in its segment table. 2285 2286 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2287 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2288 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2289 the only released version with the bug, but OpenSUSE 9 2290 contains a buggy "glibc 2.3.2". 2291 2292 The symptom of the bug is that everything crashes on startup, saying: 2293 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2294 2295 Saying Y here changes the default value of the vdso32 boot 2296 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2297 This works around the glibc bug but hurts performance. 2298 2299 If unsure, say N: if you are compiling your own kernel, you 2300 are unlikely to be using a buggy version of glibc. 2301 2302choice 2303 prompt "vsyscall table for legacy applications" 2304 depends on X86_64 2305 default LEGACY_VSYSCALL_EMULATE 2306 help 2307 Legacy user code that does not know how to find the vDSO expects 2308 to be able to issue three syscalls by calling fixed addresses in 2309 kernel space. Since this location is not randomized with ASLR, 2310 it can be used to assist security vulnerability exploitation. 2311 2312 This setting can be changed at boot time via the kernel command 2313 line parameter vsyscall=[emulate|none]. 2314 2315 On a system with recent enough glibc (2.14 or newer) and no 2316 static binaries, you can say None without a performance penalty 2317 to improve security. 2318 2319 If unsure, select "Emulate". 2320 2321 config LEGACY_VSYSCALL_EMULATE 2322 bool "Emulate" 2323 help 2324 The kernel traps and emulates calls into the fixed 2325 vsyscall address mapping. This makes the mapping 2326 non-executable, but it still contains known contents, 2327 which could be used in certain rare security vulnerability 2328 exploits. This configuration is recommended when userspace 2329 still uses the vsyscall area. 2330 2331 config LEGACY_VSYSCALL_NONE 2332 bool "None" 2333 help 2334 There will be no vsyscall mapping at all. This will 2335 eliminate any risk of ASLR bypass due to the vsyscall 2336 fixed address mapping. Attempts to use the vsyscalls 2337 will be reported to dmesg, so that either old or 2338 malicious userspace programs can be identified. 2339 2340endchoice 2341 2342config CMDLINE_BOOL 2343 bool "Built-in kernel command line" 2344 ---help--- 2345 Allow for specifying boot arguments to the kernel at 2346 build time. On some systems (e.g. embedded ones), it is 2347 necessary or convenient to provide some or all of the 2348 kernel boot arguments with the kernel itself (that is, 2349 to not rely on the boot loader to provide them.) 2350 2351 To compile command line arguments into the kernel, 2352 set this option to 'Y', then fill in the 2353 boot arguments in CONFIG_CMDLINE. 2354 2355 Systems with fully functional boot loaders (i.e. non-embedded) 2356 should leave this option set to 'N'. 2357 2358config CMDLINE 2359 string "Built-in kernel command string" 2360 depends on CMDLINE_BOOL 2361 default "" 2362 ---help--- 2363 Enter arguments here that should be compiled into the kernel 2364 image and used at boot time. If the boot loader provides a 2365 command line at boot time, it is appended to this string to 2366 form the full kernel command line, when the system boots. 2367 2368 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2369 change this behavior. 2370 2371 In most cases, the command line (whether built-in or provided 2372 by the boot loader) should specify the device for the root 2373 file system. 2374 2375config CMDLINE_OVERRIDE 2376 bool "Built-in command line overrides boot loader arguments" 2377 depends on CMDLINE_BOOL 2378 ---help--- 2379 Set this option to 'Y' to have the kernel ignore the boot loader 2380 command line, and use ONLY the built-in command line. 2381 2382 This is used to work around broken boot loaders. This should 2383 be set to 'N' under normal conditions. 2384 2385config MODIFY_LDT_SYSCALL 2386 bool "Enable the LDT (local descriptor table)" if EXPERT 2387 default y 2388 ---help--- 2389 Linux can allow user programs to install a per-process x86 2390 Local Descriptor Table (LDT) using the modify_ldt(2) system 2391 call. This is required to run 16-bit or segmented code such as 2392 DOSEMU or some Wine programs. It is also used by some very old 2393 threading libraries. 2394 2395 Enabling this feature adds a small amount of overhead to 2396 context switches and increases the low-level kernel attack 2397 surface. Disabling it removes the modify_ldt(2) system call. 2398 2399 Saying 'N' here may make sense for embedded or server kernels. 2400 2401source "kernel/livepatch/Kconfig" 2402 2403endmenu 2404 2405config ARCH_HAS_ADD_PAGES 2406 def_bool y 2407 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2408 2409config ARCH_ENABLE_MEMORY_HOTPLUG 2410 def_bool y 2411 depends on X86_64 || (X86_32 && HIGHMEM) 2412 2413config ARCH_ENABLE_MEMORY_HOTREMOVE 2414 def_bool y 2415 depends on MEMORY_HOTPLUG 2416 2417config USE_PERCPU_NUMA_NODE_ID 2418 def_bool y 2419 depends on NUMA 2420 2421config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2422 def_bool y 2423 depends on X86_64 || X86_PAE 2424 2425config ARCH_ENABLE_HUGEPAGE_MIGRATION 2426 def_bool y 2427 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2428 2429config ARCH_ENABLE_THP_MIGRATION 2430 def_bool y 2431 depends on X86_64 && TRANSPARENT_HUGEPAGE 2432 2433menu "Power management and ACPI options" 2434 2435config ARCH_HIBERNATION_HEADER 2436 def_bool y 2437 depends on X86_64 && HIBERNATION 2438 2439source "kernel/power/Kconfig" 2440 2441source "drivers/acpi/Kconfig" 2442 2443source "drivers/sfi/Kconfig" 2444 2445config X86_APM_BOOT 2446 def_bool y 2447 depends on APM 2448 2449menuconfig APM 2450 tristate "APM (Advanced Power Management) BIOS support" 2451 depends on X86_32 && PM_SLEEP 2452 ---help--- 2453 APM is a BIOS specification for saving power using several different 2454 techniques. This is mostly useful for battery powered laptops with 2455 APM compliant BIOSes. If you say Y here, the system time will be 2456 reset after a RESUME operation, the /proc/apm device will provide 2457 battery status information, and user-space programs will receive 2458 notification of APM "events" (e.g. battery status change). 2459 2460 If you select "Y" here, you can disable actual use of the APM 2461 BIOS by passing the "apm=off" option to the kernel at boot time. 2462 2463 Note that the APM support is almost completely disabled for 2464 machines with more than one CPU. 2465 2466 In order to use APM, you will need supporting software. For location 2467 and more information, read <file:Documentation/power/apm-acpi.txt> 2468 and the Battery Powered Linux mini-HOWTO, available from 2469 <http://www.tldp.org/docs.html#howto>. 2470 2471 This driver does not spin down disk drives (see the hdparm(8) 2472 manpage ("man 8 hdparm") for that), and it doesn't turn off 2473 VESA-compliant "green" monitors. 2474 2475 This driver does not support the TI 4000M TravelMate and the ACER 2476 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2477 desktop machines also don't have compliant BIOSes, and this driver 2478 may cause those machines to panic during the boot phase. 2479 2480 Generally, if you don't have a battery in your machine, there isn't 2481 much point in using this driver and you should say N. If you get 2482 random kernel OOPSes or reboots that don't seem to be related to 2483 anything, try disabling/enabling this option (or disabling/enabling 2484 APM in your BIOS). 2485 2486 Some other things you should try when experiencing seemingly random, 2487 "weird" problems: 2488 2489 1) make sure that you have enough swap space and that it is 2490 enabled. 2491 2) pass the "no-hlt" option to the kernel 2492 3) switch on floating point emulation in the kernel and pass 2493 the "no387" option to the kernel 2494 4) pass the "floppy=nodma" option to the kernel 2495 5) pass the "mem=4M" option to the kernel (thereby disabling 2496 all but the first 4 MB of RAM) 2497 6) make sure that the CPU is not over clocked. 2498 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2499 8) disable the cache from your BIOS settings 2500 9) install a fan for the video card or exchange video RAM 2501 10) install a better fan for the CPU 2502 11) exchange RAM chips 2503 12) exchange the motherboard. 2504 2505 To compile this driver as a module, choose M here: the 2506 module will be called apm. 2507 2508if APM 2509 2510config APM_IGNORE_USER_SUSPEND 2511 bool "Ignore USER SUSPEND" 2512 ---help--- 2513 This option will ignore USER SUSPEND requests. On machines with a 2514 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2515 series notebooks, it is necessary to say Y because of a BIOS bug. 2516 2517config APM_DO_ENABLE 2518 bool "Enable PM at boot time" 2519 ---help--- 2520 Enable APM features at boot time. From page 36 of the APM BIOS 2521 specification: "When disabled, the APM BIOS does not automatically 2522 power manage devices, enter the Standby State, enter the Suspend 2523 State, or take power saving steps in response to CPU Idle calls." 2524 This driver will make CPU Idle calls when Linux is idle (unless this 2525 feature is turned off -- see "Do CPU IDLE calls", below). This 2526 should always save battery power, but more complicated APM features 2527 will be dependent on your BIOS implementation. You may need to turn 2528 this option off if your computer hangs at boot time when using APM 2529 support, or if it beeps continuously instead of suspending. Turn 2530 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2531 T400CDT. This is off by default since most machines do fine without 2532 this feature. 2533 2534config APM_CPU_IDLE 2535 depends on CPU_IDLE 2536 bool "Make CPU Idle calls when idle" 2537 ---help--- 2538 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2539 On some machines, this can activate improved power savings, such as 2540 a slowed CPU clock rate, when the machine is idle. These idle calls 2541 are made after the idle loop has run for some length of time (e.g., 2542 333 mS). On some machines, this will cause a hang at boot time or 2543 whenever the CPU becomes idle. (On machines with more than one CPU, 2544 this option does nothing.) 2545 2546config APM_DISPLAY_BLANK 2547 bool "Enable console blanking using APM" 2548 ---help--- 2549 Enable console blanking using the APM. Some laptops can use this to 2550 turn off the LCD backlight when the screen blanker of the Linux 2551 virtual console blanks the screen. Note that this is only used by 2552 the virtual console screen blanker, and won't turn off the backlight 2553 when using the X Window system. This also doesn't have anything to 2554 do with your VESA-compliant power-saving monitor. Further, this 2555 option doesn't work for all laptops -- it might not turn off your 2556 backlight at all, or it might print a lot of errors to the console, 2557 especially if you are using gpm. 2558 2559config APM_ALLOW_INTS 2560 bool "Allow interrupts during APM BIOS calls" 2561 ---help--- 2562 Normally we disable external interrupts while we are making calls to 2563 the APM BIOS as a measure to lessen the effects of a badly behaving 2564 BIOS implementation. The BIOS should reenable interrupts if it 2565 needs to. Unfortunately, some BIOSes do not -- especially those in 2566 many of the newer IBM Thinkpads. If you experience hangs when you 2567 suspend, try setting this to Y. Otherwise, say N. 2568 2569endif # APM 2570 2571source "drivers/cpufreq/Kconfig" 2572 2573source "drivers/cpuidle/Kconfig" 2574 2575source "drivers/idle/Kconfig" 2576 2577endmenu 2578 2579 2580menu "Bus options (PCI etc.)" 2581 2582config PCI 2583 bool "PCI support" 2584 default y 2585 ---help--- 2586 Find out whether you have a PCI motherboard. PCI is the name of a 2587 bus system, i.e. the way the CPU talks to the other stuff inside 2588 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or 2589 VESA. If you have PCI, say Y, otherwise N. 2590 2591choice 2592 prompt "PCI access mode" 2593 depends on X86_32 && PCI 2594 default PCI_GOANY 2595 ---help--- 2596 On PCI systems, the BIOS can be used to detect the PCI devices and 2597 determine their configuration. However, some old PCI motherboards 2598 have BIOS bugs and may crash if this is done. Also, some embedded 2599 PCI-based systems don't have any BIOS at all. Linux can also try to 2600 detect the PCI hardware directly without using the BIOS. 2601 2602 With this option, you can specify how Linux should detect the 2603 PCI devices. If you choose "BIOS", the BIOS will be used, 2604 if you choose "Direct", the BIOS won't be used, and if you 2605 choose "MMConfig", then PCI Express MMCONFIG will be used. 2606 If you choose "Any", the kernel will try MMCONFIG, then the 2607 direct access method and falls back to the BIOS if that doesn't 2608 work. If unsure, go with the default, which is "Any". 2609 2610config PCI_GOBIOS 2611 bool "BIOS" 2612 2613config PCI_GOMMCONFIG 2614 bool "MMConfig" 2615 2616config PCI_GODIRECT 2617 bool "Direct" 2618 2619config PCI_GOOLPC 2620 bool "OLPC XO-1" 2621 depends on OLPC 2622 2623config PCI_GOANY 2624 bool "Any" 2625 2626endchoice 2627 2628config PCI_BIOS 2629 def_bool y 2630 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2631 2632# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2633config PCI_DIRECT 2634 def_bool y 2635 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2636 2637config PCI_MMCONFIG 2638 bool "Support mmconfig PCI config space access" if X86_64 2639 default y 2640 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2641 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2642 2643config PCI_OLPC 2644 def_bool y 2645 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2646 2647config PCI_XEN 2648 def_bool y 2649 depends on PCI && XEN 2650 select SWIOTLB_XEN 2651 2652config PCI_DOMAINS 2653 def_bool y 2654 depends on PCI 2655 2656config MMCONF_FAM10H 2657 def_bool y 2658 depends on X86_64 && PCI_MMCONFIG && ACPI 2659 2660config PCI_CNB20LE_QUIRK 2661 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2662 depends on PCI 2663 help 2664 Read the PCI windows out of the CNB20LE host bridge. This allows 2665 PCI hotplug to work on systems with the CNB20LE chipset which do 2666 not have ACPI. 2667 2668 There's no public spec for this chipset, and this functionality 2669 is known to be incomplete. 2670 2671 You should say N unless you know you need this. 2672 2673source "drivers/pci/Kconfig" 2674 2675config ISA_BUS 2676 bool "ISA bus support on modern systems" if EXPERT 2677 help 2678 Expose ISA bus device drivers and options available for selection and 2679 configuration. Enable this option if your target machine has an ISA 2680 bus. ISA is an older system, displaced by PCI and newer bus 2681 architectures -- if your target machine is modern, it probably does 2682 not have an ISA bus. 2683 2684 If unsure, say N. 2685 2686# x86_64 have no ISA slots, but can have ISA-style DMA. 2687config ISA_DMA_API 2688 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2689 default y 2690 help 2691 Enables ISA-style DMA support for devices requiring such controllers. 2692 If unsure, say Y. 2693 2694if X86_32 2695 2696config ISA 2697 bool "ISA support" 2698 ---help--- 2699 Find out whether you have ISA slots on your motherboard. ISA is the 2700 name of a bus system, i.e. the way the CPU talks to the other stuff 2701 inside your box. Other bus systems are PCI, EISA, MicroChannel 2702 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2703 newer boards don't support it. If you have ISA, say Y, otherwise N. 2704 2705config EISA 2706 bool "EISA support" 2707 depends on ISA 2708 ---help--- 2709 The Extended Industry Standard Architecture (EISA) bus was 2710 developed as an open alternative to the IBM MicroChannel bus. 2711 2712 The EISA bus provided some of the features of the IBM MicroChannel 2713 bus while maintaining backward compatibility with cards made for 2714 the older ISA bus. The EISA bus saw limited use between 1988 and 2715 1995 when it was made obsolete by the PCI bus. 2716 2717 Say Y here if you are building a kernel for an EISA-based machine. 2718 2719 Otherwise, say N. 2720 2721source "drivers/eisa/Kconfig" 2722 2723config SCx200 2724 tristate "NatSemi SCx200 support" 2725 ---help--- 2726 This provides basic support for National Semiconductor's 2727 (now AMD's) Geode processors. The driver probes for the 2728 PCI-IDs of several on-chip devices, so its a good dependency 2729 for other scx200_* drivers. 2730 2731 If compiled as a module, the driver is named scx200. 2732 2733config SCx200HR_TIMER 2734 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2735 depends on SCx200 2736 default y 2737 ---help--- 2738 This driver provides a clocksource built upon the on-chip 2739 27MHz high-resolution timer. Its also a workaround for 2740 NSC Geode SC-1100's buggy TSC, which loses time when the 2741 processor goes idle (as is done by the scheduler). The 2742 other workaround is idle=poll boot option. 2743 2744config OLPC 2745 bool "One Laptop Per Child support" 2746 depends on !X86_PAE 2747 select GPIOLIB 2748 select OF 2749 select OF_PROMTREE 2750 select IRQ_DOMAIN 2751 ---help--- 2752 Add support for detecting the unique features of the OLPC 2753 XO hardware. 2754 2755config OLPC_XO1_PM 2756 bool "OLPC XO-1 Power Management" 2757 depends on OLPC && MFD_CS5535 && PM_SLEEP 2758 select MFD_CORE 2759 ---help--- 2760 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2761 2762config OLPC_XO1_RTC 2763 bool "OLPC XO-1 Real Time Clock" 2764 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2765 ---help--- 2766 Add support for the XO-1 real time clock, which can be used as a 2767 programmable wakeup source. 2768 2769config OLPC_XO1_SCI 2770 bool "OLPC XO-1 SCI extras" 2771 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2772 depends on INPUT=y 2773 select POWER_SUPPLY 2774 ---help--- 2775 Add support for SCI-based features of the OLPC XO-1 laptop: 2776 - EC-driven system wakeups 2777 - Power button 2778 - Ebook switch 2779 - Lid switch 2780 - AC adapter status updates 2781 - Battery status updates 2782 2783config OLPC_XO15_SCI 2784 bool "OLPC XO-1.5 SCI extras" 2785 depends on OLPC && ACPI 2786 select POWER_SUPPLY 2787 ---help--- 2788 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2789 - EC-driven system wakeups 2790 - AC adapter status updates 2791 - Battery status updates 2792 2793config ALIX 2794 bool "PCEngines ALIX System Support (LED setup)" 2795 select GPIOLIB 2796 ---help--- 2797 This option enables system support for the PCEngines ALIX. 2798 At present this just sets up LEDs for GPIO control on 2799 ALIX2/3/6 boards. However, other system specific setup should 2800 get added here. 2801 2802 Note: You must still enable the drivers for GPIO and LED support 2803 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2804 2805 Note: You have to set alix.force=1 for boards with Award BIOS. 2806 2807config NET5501 2808 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2809 select GPIOLIB 2810 ---help--- 2811 This option enables system support for the Soekris Engineering net5501. 2812 2813config GEOS 2814 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2815 select GPIOLIB 2816 depends on DMI 2817 ---help--- 2818 This option enables system support for the Traverse Technologies GEOS. 2819 2820config TS5500 2821 bool "Technologic Systems TS-5500 platform support" 2822 depends on MELAN 2823 select CHECK_SIGNATURE 2824 select NEW_LEDS 2825 select LEDS_CLASS 2826 ---help--- 2827 This option enables system support for the Technologic Systems TS-5500. 2828 2829endif # X86_32 2830 2831config AMD_NB 2832 def_bool y 2833 depends on CPU_SUP_AMD && PCI 2834 2835source "drivers/pcmcia/Kconfig" 2836 2837config RAPIDIO 2838 tristate "RapidIO support" 2839 depends on PCI 2840 default n 2841 help 2842 If enabled this option will include drivers and the core 2843 infrastructure code to support RapidIO interconnect devices. 2844 2845source "drivers/rapidio/Kconfig" 2846 2847config X86_SYSFB 2848 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2849 help 2850 Firmwares often provide initial graphics framebuffers so the BIOS, 2851 bootloader or kernel can show basic video-output during boot for 2852 user-guidance and debugging. Historically, x86 used the VESA BIOS 2853 Extensions and EFI-framebuffers for this, which are mostly limited 2854 to x86. 2855 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2856 framebuffers so the new generic system-framebuffer drivers can be 2857 used on x86. If the framebuffer is not compatible with the generic 2858 modes, it is adverticed as fallback platform framebuffer so legacy 2859 drivers like efifb, vesafb and uvesafb can pick it up. 2860 If this option is not selected, all system framebuffers are always 2861 marked as fallback platform framebuffers as usual. 2862 2863 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2864 not be able to pick up generic system framebuffers if this option 2865 is selected. You are highly encouraged to enable simplefb as 2866 replacement if you select this option. simplefb can correctly deal 2867 with generic system framebuffers. But you should still keep vesafb 2868 and others enabled as fallback if a system framebuffer is 2869 incompatible with simplefb. 2870 2871 If unsure, say Y. 2872 2873endmenu 2874 2875 2876menu "Executable file formats / Emulations" 2877 2878source "fs/Kconfig.binfmt" 2879 2880config IA32_EMULATION 2881 bool "IA32 Emulation" 2882 depends on X86_64 2883 select ARCH_WANT_OLD_COMPAT_IPC 2884 select BINFMT_ELF 2885 select COMPAT_BINFMT_ELF 2886 select COMPAT_OLD_SIGACTION 2887 ---help--- 2888 Include code to run legacy 32-bit programs under a 2889 64-bit kernel. You should likely turn this on, unless you're 2890 100% sure that you don't have any 32-bit programs left. 2891 2892config IA32_AOUT 2893 tristate "IA32 a.out support" 2894 depends on IA32_EMULATION 2895 ---help--- 2896 Support old a.out binaries in the 32bit emulation. 2897 2898config X86_X32 2899 bool "x32 ABI for 64-bit mode" 2900 depends on X86_64 2901 ---help--- 2902 Include code to run binaries for the x32 native 32-bit ABI 2903 for 64-bit processors. An x32 process gets access to the 2904 full 64-bit register file and wide data path while leaving 2905 pointers at 32 bits for smaller memory footprint. 2906 2907 You will need a recent binutils (2.22 or later) with 2908 elf32_x86_64 support enabled to compile a kernel with this 2909 option set. 2910 2911config COMPAT_32 2912 def_bool y 2913 depends on IA32_EMULATION || X86_32 2914 select HAVE_UID16 2915 select OLD_SIGSUSPEND3 2916 2917config COMPAT 2918 def_bool y 2919 depends on IA32_EMULATION || X86_X32 2920 2921if COMPAT 2922config COMPAT_FOR_U64_ALIGNMENT 2923 def_bool y 2924 2925config SYSVIPC_COMPAT 2926 def_bool y 2927 depends on SYSVIPC 2928endif 2929 2930endmenu 2931 2932 2933config HAVE_ATOMIC_IOMAP 2934 def_bool y 2935 depends on X86_32 2936 2937config X86_DEV_DMA_OPS 2938 bool 2939 depends on X86_64 || STA2X11 2940 2941config X86_DMA_REMAP 2942 bool 2943 depends on STA2X11 2944 2945config HAVE_GENERIC_GUP 2946 def_bool y 2947 2948source "net/Kconfig" 2949 2950source "drivers/Kconfig" 2951 2952source "drivers/firmware/Kconfig" 2953 2954source "fs/Kconfig" 2955 2956source "arch/x86/Kconfig.debug" 2957 2958source "security/Kconfig" 2959 2960source "crypto/Kconfig" 2961 2962source "arch/x86/kvm/Kconfig" 2963 2964source "lib/Kconfig" 2965