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 NEED_DMA_MAP_STATE 32 select SWIOTLB 33 select X86_DEV_DMA_OPS 34 select ARCH_HAS_SYSCALL_WRAPPER 35 36# 37# Arch settings 38# 39# ( Note that options that are marked 'if X86_64' could in principle be 40# ported to 32-bit as well. ) 41# 42config X86 43 def_bool y 44 # 45 # Note: keep this list sorted alphabetically 46 # 47 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 48 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 49 select ANON_INODES 50 select ARCH_CLOCKSOURCE_DATA 51 select ARCH_DISCARD_MEMBLOCK 52 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 53 select ARCH_HAS_DEBUG_VIRTUAL 54 select ARCH_HAS_DEVMEM_IS_ALLOWED 55 select ARCH_HAS_ELF_RANDOMIZE 56 select ARCH_HAS_FAST_MULTIPLIER 57 select ARCH_HAS_FILTER_PGPROT 58 select ARCH_HAS_FORTIFY_SOURCE 59 select ARCH_HAS_GCOV_PROFILE_ALL 60 select ARCH_HAS_KCOV if X86_64 61 select ARCH_HAS_MEMBARRIER_SYNC_CORE 62 select ARCH_HAS_PMEM_API if X86_64 63 select ARCH_HAS_REFCOUNT 64 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 65 select ARCH_HAS_UACCESS_MCSAFE if X86_64 66 select ARCH_HAS_SET_MEMORY 67 select ARCH_HAS_SG_CHAIN 68 select ARCH_HAS_STRICT_KERNEL_RWX 69 select ARCH_HAS_STRICT_MODULE_RWX 70 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 71 select ARCH_HAS_UBSAN_SANITIZE_ALL 72 select ARCH_HAS_ZONE_DEVICE if X86_64 73 select ARCH_HAVE_NMI_SAFE_CMPXCHG 74 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 75 select ARCH_MIGHT_HAVE_PC_PARPORT 76 select ARCH_MIGHT_HAVE_PC_SERIO 77 select ARCH_SUPPORTS_ATOMIC_RMW 78 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 79 select ARCH_USE_BUILTIN_BSWAP 80 select ARCH_USE_QUEUED_RWLOCKS 81 select ARCH_USE_QUEUED_SPINLOCKS 82 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 83 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 84 select ARCH_WANTS_THP_SWAP if X86_64 85 select BUILDTIME_EXTABLE_SORT 86 select CLKEVT_I8253 87 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 88 select CLOCKSOURCE_WATCHDOG 89 select DCACHE_WORD_ACCESS 90 select DMA_DIRECT_OPS 91 select EDAC_ATOMIC_SCRUB 92 select EDAC_SUPPORT 93 select GENERIC_CLOCKEVENTS 94 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 95 select GENERIC_CLOCKEVENTS_MIN_ADJUST 96 select GENERIC_CMOS_UPDATE 97 select GENERIC_CPU_AUTOPROBE 98 select GENERIC_CPU_VULNERABILITIES 99 select GENERIC_EARLY_IOREMAP 100 select GENERIC_FIND_FIRST_BIT 101 select GENERIC_IOMAP 102 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 103 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 104 select GENERIC_IRQ_MIGRATION if SMP 105 select GENERIC_IRQ_PROBE 106 select GENERIC_IRQ_RESERVATION_MODE 107 select GENERIC_IRQ_SHOW 108 select GENERIC_PENDING_IRQ if SMP 109 select GENERIC_SMP_IDLE_THREAD 110 select GENERIC_STRNCPY_FROM_USER 111 select GENERIC_STRNLEN_USER 112 select GENERIC_TIME_VSYSCALL 113 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 114 select HAVE_ACPI_APEI if ACPI 115 select HAVE_ACPI_APEI_NMI if ACPI 116 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 117 select HAVE_ARCH_AUDITSYSCALL 118 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 119 select HAVE_ARCH_JUMP_LABEL 120 select HAVE_ARCH_KASAN if X86_64 121 select HAVE_ARCH_KGDB 122 select HAVE_ARCH_MMAP_RND_BITS if MMU 123 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 124 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 125 select HAVE_ARCH_SECCOMP_FILTER 126 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 127 select HAVE_ARCH_TRACEHOOK 128 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 129 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 130 select HAVE_ARCH_VMAP_STACK if X86_64 131 select HAVE_ARCH_WITHIN_STACK_FRAMES 132 select HAVE_CC_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 133 select HAVE_CMPXCHG_DOUBLE 134 select HAVE_CMPXCHG_LOCAL 135 select HAVE_CONTEXT_TRACKING if X86_64 136 select HAVE_COPY_THREAD_TLS 137 select HAVE_C_RECORDMCOUNT 138 select HAVE_DEBUG_KMEMLEAK 139 select HAVE_DEBUG_STACKOVERFLOW 140 select HAVE_DMA_CONTIGUOUS 141 select HAVE_DYNAMIC_FTRACE 142 select HAVE_DYNAMIC_FTRACE_WITH_REGS 143 select HAVE_EBPF_JIT 144 select HAVE_EFFICIENT_UNALIGNED_ACCESS 145 select HAVE_EXIT_THREAD 146 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 147 select HAVE_FTRACE_MCOUNT_RECORD 148 select HAVE_FUNCTION_GRAPH_TRACER 149 select HAVE_FUNCTION_TRACER 150 select HAVE_GCC_PLUGINS 151 select HAVE_HW_BREAKPOINT 152 select HAVE_IDE 153 select HAVE_IOREMAP_PROT 154 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 155 select HAVE_IRQ_TIME_ACCOUNTING 156 select HAVE_KERNEL_BZIP2 157 select HAVE_KERNEL_GZIP 158 select HAVE_KERNEL_LZ4 159 select HAVE_KERNEL_LZMA 160 select HAVE_KERNEL_LZO 161 select HAVE_KERNEL_XZ 162 select HAVE_KPROBES 163 select HAVE_KPROBES_ON_FTRACE 164 select HAVE_FUNCTION_ERROR_INJECTION 165 select HAVE_KRETPROBES 166 select HAVE_KVM 167 select HAVE_LIVEPATCH if X86_64 168 select HAVE_MEMBLOCK 169 select HAVE_MEMBLOCK_NODE_MAP 170 select HAVE_MIXED_BREAKPOINTS_REGS 171 select HAVE_MOD_ARCH_SPECIFIC 172 select HAVE_NMI 173 select HAVE_OPROFILE 174 select HAVE_OPTPROBES 175 select HAVE_PCSPKR_PLATFORM 176 select HAVE_PERF_EVENTS 177 select HAVE_PERF_EVENTS_NMI 178 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 179 select HAVE_PERF_REGS 180 select HAVE_PERF_USER_STACK_DUMP 181 select HAVE_RCU_TABLE_FREE 182 select HAVE_REGS_AND_STACK_ACCESS_API 183 select HAVE_RELIABLE_STACKTRACE if X86_64 && UNWINDER_FRAME_POINTER && STACK_VALIDATION 184 select HAVE_STACK_VALIDATION if X86_64 185 select HAVE_SYSCALL_TRACEPOINTS 186 select HAVE_UNSTABLE_SCHED_CLOCK 187 select HAVE_USER_RETURN_NOTIFIER 188 select IRQ_FORCED_THREADING 189 select NEED_SG_DMA_LENGTH 190 select PCI_LOCKLESS_CONFIG 191 select PERF_EVENTS 192 select RTC_LIB 193 select RTC_MC146818_LIB 194 select SPARSE_IRQ 195 select SRCU 196 select SYSCTL_EXCEPTION_TRACE 197 select THREAD_INFO_IN_TASK 198 select USER_STACKTRACE_SUPPORT 199 select VIRT_TO_BUS 200 select X86_FEATURE_NAMES if PROC_FS 201 202config INSTRUCTION_DECODER 203 def_bool y 204 depends on KPROBES || PERF_EVENTS || UPROBES 205 206config OUTPUT_FORMAT 207 string 208 default "elf32-i386" if X86_32 209 default "elf64-x86-64" if X86_64 210 211config ARCH_DEFCONFIG 212 string 213 default "arch/x86/configs/i386_defconfig" if X86_32 214 default "arch/x86/configs/x86_64_defconfig" if X86_64 215 216config LOCKDEP_SUPPORT 217 def_bool y 218 219config STACKTRACE_SUPPORT 220 def_bool y 221 222config MMU 223 def_bool y 224 225config ARCH_MMAP_RND_BITS_MIN 226 default 28 if 64BIT 227 default 8 228 229config ARCH_MMAP_RND_BITS_MAX 230 default 32 if 64BIT 231 default 16 232 233config ARCH_MMAP_RND_COMPAT_BITS_MIN 234 default 8 235 236config ARCH_MMAP_RND_COMPAT_BITS_MAX 237 default 16 238 239config SBUS 240 bool 241 242config GENERIC_ISA_DMA 243 def_bool y 244 depends on ISA_DMA_API 245 246config GENERIC_BUG 247 def_bool y 248 depends on BUG 249 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 250 251config GENERIC_BUG_RELATIVE_POINTERS 252 bool 253 254config GENERIC_HWEIGHT 255 def_bool y 256 257config ARCH_MAY_HAVE_PC_FDC 258 def_bool y 259 depends on ISA_DMA_API 260 261config RWSEM_XCHGADD_ALGORITHM 262 def_bool y 263 264config GENERIC_CALIBRATE_DELAY 265 def_bool y 266 267config ARCH_HAS_CPU_RELAX 268 def_bool y 269 270config ARCH_HAS_CACHE_LINE_SIZE 271 def_bool y 272 273config ARCH_HAS_FILTER_PGPROT 274 def_bool y 275 276config HAVE_SETUP_PER_CPU_AREA 277 def_bool y 278 279config NEED_PER_CPU_EMBED_FIRST_CHUNK 280 def_bool y 281 282config NEED_PER_CPU_PAGE_FIRST_CHUNK 283 def_bool y 284 285config ARCH_HIBERNATION_POSSIBLE 286 def_bool y 287 288config ARCH_SUSPEND_POSSIBLE 289 def_bool y 290 291config ARCH_WANT_HUGE_PMD_SHARE 292 def_bool y 293 294config ARCH_WANT_GENERAL_HUGETLB 295 def_bool y 296 297config ZONE_DMA32 298 def_bool y if X86_64 299 300config AUDIT_ARCH 301 def_bool y if X86_64 302 303config ARCH_SUPPORTS_OPTIMIZED_INLINING 304 def_bool y 305 306config ARCH_SUPPORTS_DEBUG_PAGEALLOC 307 def_bool y 308 309config KASAN_SHADOW_OFFSET 310 hex 311 depends on KASAN 312 default 0xdffffc0000000000 313 314config HAVE_INTEL_TXT 315 def_bool y 316 depends on INTEL_IOMMU && ACPI 317 318config X86_32_SMP 319 def_bool y 320 depends on X86_32 && SMP 321 322config X86_64_SMP 323 def_bool y 324 depends on X86_64 && SMP 325 326config X86_32_LAZY_GS 327 def_bool y 328 depends on X86_32 && CC_STACKPROTECTOR_NONE 329 330config ARCH_SUPPORTS_UPROBES 331 def_bool y 332 333config FIX_EARLYCON_MEM 334 def_bool y 335 336config PGTABLE_LEVELS 337 int 338 default 5 if X86_5LEVEL 339 default 4 if X86_64 340 default 3 if X86_PAE 341 default 2 342 343source "init/Kconfig" 344 345config CC_HAS_SANE_STACKPROTECTOR 346 bool 347 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 348 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 349 help 350 We have to make sure stack protector is unconditionally disabled if 351 the compiler produces broken code. 352 353source "kernel/Kconfig.freezer" 354 355menu "Processor type and features" 356 357config ZONE_DMA 358 bool "DMA memory allocation support" if EXPERT 359 default y 360 help 361 DMA memory allocation support allows devices with less than 32-bit 362 addressing to allocate within the first 16MB of address space. 363 Disable if no such devices will be used. 364 365 If unsure, say Y. 366 367config SMP 368 bool "Symmetric multi-processing support" 369 ---help--- 370 This enables support for systems with more than one CPU. If you have 371 a system with only one CPU, say N. If you have a system with more 372 than one CPU, say Y. 373 374 If you say N here, the kernel will run on uni- and multiprocessor 375 machines, but will use only one CPU of a multiprocessor machine. If 376 you say Y here, the kernel will run on many, but not all, 377 uniprocessor machines. On a uniprocessor machine, the kernel 378 will run faster if you say N here. 379 380 Note that if you say Y here and choose architecture "586" or 381 "Pentium" under "Processor family", the kernel will not work on 486 382 architectures. Similarly, multiprocessor kernels for the "PPro" 383 architecture may not work on all Pentium based boards. 384 385 People using multiprocessor machines who say Y here should also say 386 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 387 Management" code will be disabled if you say Y here. 388 389 See also <file:Documentation/x86/i386/IO-APIC.txt>, 390 <file:Documentation/lockup-watchdogs.txt> and the SMP-HOWTO available at 391 <http://www.tldp.org/docs.html#howto>. 392 393 If you don't know what to do here, say N. 394 395config X86_FEATURE_NAMES 396 bool "Processor feature human-readable names" if EMBEDDED 397 default y 398 ---help--- 399 This option compiles in a table of x86 feature bits and corresponding 400 names. This is required to support /proc/cpuinfo and a few kernel 401 messages. You can disable this to save space, at the expense of 402 making those few kernel messages show numeric feature bits instead. 403 404 If in doubt, say Y. 405 406config X86_X2APIC 407 bool "Support x2apic" 408 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 409 ---help--- 410 This enables x2apic support on CPUs that have this feature. 411 412 This allows 32-bit apic IDs (so it can support very large systems), 413 and accesses the local apic via MSRs not via mmio. 414 415 If you don't know what to do here, say N. 416 417config X86_MPPARSE 418 bool "Enable MPS table" if ACPI || SFI 419 default y 420 depends on X86_LOCAL_APIC 421 ---help--- 422 For old smp systems that do not have proper acpi support. Newer systems 423 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 424 425config GOLDFISH 426 def_bool y 427 depends on X86_GOLDFISH 428 429config RETPOLINE 430 bool "Avoid speculative indirect branches in kernel" 431 default y 432 select STACK_VALIDATION if HAVE_STACK_VALIDATION 433 help 434 Compile kernel with the retpoline compiler options to guard against 435 kernel-to-user data leaks by avoiding speculative indirect 436 branches. Requires a compiler with -mindirect-branch=thunk-extern 437 support for full protection. The kernel may run slower. 438 439 Without compiler support, at least indirect branches in assembler 440 code are eliminated. Since this includes the syscall entry path, 441 it is not entirely pointless. 442 443config INTEL_RDT 444 bool "Intel Resource Director Technology support" 445 default n 446 depends on X86 && CPU_SUP_INTEL 447 select KERNFS 448 help 449 Select to enable resource allocation and monitoring which are 450 sub-features of Intel Resource Director Technology(RDT). More 451 information about RDT can be found in the Intel x86 452 Architecture Software Developer Manual. 453 454 Say N if unsure. 455 456if X86_32 457config X86_BIGSMP 458 bool "Support for big SMP systems with more than 8 CPUs" 459 depends on SMP 460 ---help--- 461 This option is needed for the systems that have more than 8 CPUs 462 463config X86_EXTENDED_PLATFORM 464 bool "Support for extended (non-PC) x86 platforms" 465 default y 466 ---help--- 467 If you disable this option then the kernel will only support 468 standard PC platforms. (which covers the vast majority of 469 systems out there.) 470 471 If you enable this option then you'll be able to select support 472 for the following (non-PC) 32 bit x86 platforms: 473 Goldfish (Android emulator) 474 AMD Elan 475 RDC R-321x SoC 476 SGI 320/540 (Visual Workstation) 477 STA2X11-based (e.g. Northville) 478 Moorestown MID devices 479 480 If you have one of these systems, or if you want to build a 481 generic distribution kernel, say Y here - otherwise say N. 482endif 483 484if X86_64 485config X86_EXTENDED_PLATFORM 486 bool "Support for extended (non-PC) x86 platforms" 487 default y 488 ---help--- 489 If you disable this option then the kernel will only support 490 standard PC platforms. (which covers the vast majority of 491 systems out there.) 492 493 If you enable this option then you'll be able to select support 494 for the following (non-PC) 64 bit x86 platforms: 495 Numascale NumaChip 496 ScaleMP vSMP 497 SGI Ultraviolet 498 499 If you have one of these systems, or if you want to build a 500 generic distribution kernel, say Y here - otherwise say N. 501endif 502# This is an alphabetically sorted list of 64 bit extended platforms 503# Please maintain the alphabetic order if and when there are additions 504config X86_NUMACHIP 505 bool "Numascale NumaChip" 506 depends on X86_64 507 depends on X86_EXTENDED_PLATFORM 508 depends on NUMA 509 depends on SMP 510 depends on X86_X2APIC 511 depends on PCI_MMCONFIG 512 ---help--- 513 Adds support for Numascale NumaChip large-SMP systems. Needed to 514 enable more than ~168 cores. 515 If you don't have one of these, you should say N here. 516 517config X86_VSMP 518 bool "ScaleMP vSMP" 519 select HYPERVISOR_GUEST 520 select PARAVIRT 521 depends on X86_64 && PCI 522 depends on X86_EXTENDED_PLATFORM 523 depends on SMP 524 ---help--- 525 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 526 supposed to run on these EM64T-based machines. Only choose this option 527 if you have one of these machines. 528 529config X86_UV 530 bool "SGI Ultraviolet" 531 depends on X86_64 532 depends on X86_EXTENDED_PLATFORM 533 depends on NUMA 534 depends on EFI 535 depends on X86_X2APIC 536 depends on PCI 537 ---help--- 538 This option is needed in order to support SGI Ultraviolet systems. 539 If you don't have one of these, you should say N here. 540 541# Following is an alphabetically sorted list of 32 bit extended platforms 542# Please maintain the alphabetic order if and when there are additions 543 544config X86_GOLDFISH 545 bool "Goldfish (Virtual Platform)" 546 depends on X86_EXTENDED_PLATFORM 547 ---help--- 548 Enable support for the Goldfish virtual platform used primarily 549 for Android development. Unless you are building for the Android 550 Goldfish emulator say N here. 551 552config X86_INTEL_CE 553 bool "CE4100 TV platform" 554 depends on PCI 555 depends on PCI_GODIRECT 556 depends on X86_IO_APIC 557 depends on X86_32 558 depends on X86_EXTENDED_PLATFORM 559 select X86_REBOOTFIXUPS 560 select OF 561 select OF_EARLY_FLATTREE 562 ---help--- 563 Select for the Intel CE media processor (CE4100) SOC. 564 This option compiles in support for the CE4100 SOC for settop 565 boxes and media devices. 566 567config X86_INTEL_MID 568 bool "Intel MID platform support" 569 depends on X86_EXTENDED_PLATFORM 570 depends on X86_PLATFORM_DEVICES 571 depends on PCI 572 depends on X86_64 || (PCI_GOANY && X86_32) 573 depends on X86_IO_APIC 574 select SFI 575 select I2C 576 select DW_APB_TIMER 577 select APB_TIMER 578 select INTEL_SCU_IPC 579 select MFD_INTEL_MSIC 580 ---help--- 581 Select to build a kernel capable of supporting Intel MID (Mobile 582 Internet Device) platform systems which do not have the PCI legacy 583 interfaces. If you are building for a PC class system say N here. 584 585 Intel MID platforms are based on an Intel processor and chipset which 586 consume less power than most of the x86 derivatives. 587 588config X86_INTEL_QUARK 589 bool "Intel Quark platform support" 590 depends on X86_32 591 depends on X86_EXTENDED_PLATFORM 592 depends on X86_PLATFORM_DEVICES 593 depends on X86_TSC 594 depends on PCI 595 depends on PCI_GOANY 596 depends on X86_IO_APIC 597 select IOSF_MBI 598 select INTEL_IMR 599 select COMMON_CLK 600 ---help--- 601 Select to include support for Quark X1000 SoC. 602 Say Y here if you have a Quark based system such as the Arduino 603 compatible Intel Galileo. 604 605config X86_INTEL_LPSS 606 bool "Intel Low Power Subsystem Support" 607 depends on X86 && ACPI 608 select COMMON_CLK 609 select PINCTRL 610 select IOSF_MBI 611 ---help--- 612 Select to build support for Intel Low Power Subsystem such as 613 found on Intel Lynxpoint PCH. Selecting this option enables 614 things like clock tree (common clock framework) and pincontrol 615 which are needed by the LPSS peripheral drivers. 616 617config X86_AMD_PLATFORM_DEVICE 618 bool "AMD ACPI2Platform devices support" 619 depends on ACPI 620 select COMMON_CLK 621 select PINCTRL 622 ---help--- 623 Select to interpret AMD specific ACPI device to platform device 624 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 625 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 626 implemented under PINCTRL subsystem. 627 628config IOSF_MBI 629 tristate "Intel SoC IOSF Sideband support for SoC platforms" 630 depends on PCI 631 ---help--- 632 This option enables sideband register access support for Intel SoC 633 platforms. On these platforms the IOSF sideband is used in lieu of 634 MSR's for some register accesses, mostly but not limited to thermal 635 and power. Drivers may query the availability of this device to 636 determine if they need the sideband in order to work on these 637 platforms. The sideband is available on the following SoC products. 638 This list is not meant to be exclusive. 639 - BayTrail 640 - Braswell 641 - Quark 642 643 You should say Y if you are running a kernel on one of these SoC's. 644 645config IOSF_MBI_DEBUG 646 bool "Enable IOSF sideband access through debugfs" 647 depends on IOSF_MBI && DEBUG_FS 648 ---help--- 649 Select this option to expose the IOSF sideband access registers (MCR, 650 MDR, MCRX) through debugfs to write and read register information from 651 different units on the SoC. This is most useful for obtaining device 652 state information for debug and analysis. As this is a general access 653 mechanism, users of this option would have specific knowledge of the 654 device they want to access. 655 656 If you don't require the option or are in doubt, say N. 657 658config X86_RDC321X 659 bool "RDC R-321x SoC" 660 depends on X86_32 661 depends on X86_EXTENDED_PLATFORM 662 select M486 663 select X86_REBOOTFIXUPS 664 ---help--- 665 This option is needed for RDC R-321x system-on-chip, also known 666 as R-8610-(G). 667 If you don't have one of these chips, you should say N here. 668 669config X86_32_NON_STANDARD 670 bool "Support non-standard 32-bit SMP architectures" 671 depends on X86_32 && SMP 672 depends on X86_EXTENDED_PLATFORM 673 ---help--- 674 This option compiles in the bigsmp and STA2X11 default 675 subarchitectures. It is intended for a generic binary 676 kernel. If you select them all, kernel will probe it one by 677 one and will fallback to default. 678 679# Alphabetically sorted list of Non standard 32 bit platforms 680 681config X86_SUPPORTS_MEMORY_FAILURE 682 def_bool y 683 # MCE code calls memory_failure(): 684 depends on X86_MCE 685 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 686 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 687 depends on X86_64 || !SPARSEMEM 688 select ARCH_SUPPORTS_MEMORY_FAILURE 689 690config STA2X11 691 bool "STA2X11 Companion Chip Support" 692 depends on X86_32_NON_STANDARD && PCI 693 select ARCH_HAS_PHYS_TO_DMA 694 select X86_DEV_DMA_OPS 695 select X86_DMA_REMAP 696 select SWIOTLB 697 select MFD_STA2X11 698 select GPIOLIB 699 default n 700 ---help--- 701 This adds support for boards based on the STA2X11 IO-Hub, 702 a.k.a. "ConneXt". The chip is used in place of the standard 703 PC chipset, so all "standard" peripherals are missing. If this 704 option is selected the kernel will still be able to boot on 705 standard PC machines. 706 707config X86_32_IRIS 708 tristate "Eurobraille/Iris poweroff module" 709 depends on X86_32 710 ---help--- 711 The Iris machines from EuroBraille do not have APM or ACPI support 712 to shut themselves down properly. A special I/O sequence is 713 needed to do so, which is what this module does at 714 kernel shutdown. 715 716 This is only for Iris machines from EuroBraille. 717 718 If unused, say N. 719 720config SCHED_OMIT_FRAME_POINTER 721 def_bool y 722 prompt "Single-depth WCHAN output" 723 depends on X86 724 ---help--- 725 Calculate simpler /proc/<PID>/wchan values. If this option 726 is disabled then wchan values will recurse back to the 727 caller function. This provides more accurate wchan values, 728 at the expense of slightly more scheduling overhead. 729 730 If in doubt, say "Y". 731 732menuconfig HYPERVISOR_GUEST 733 bool "Linux guest support" 734 ---help--- 735 Say Y here to enable options for running Linux under various hyper- 736 visors. This option enables basic hypervisor detection and platform 737 setup. 738 739 If you say N, all options in this submenu will be skipped and 740 disabled, and Linux guest support won't be built in. 741 742if HYPERVISOR_GUEST 743 744config PARAVIRT 745 bool "Enable paravirtualization code" 746 ---help--- 747 This changes the kernel so it can modify itself when it is run 748 under a hypervisor, potentially improving performance significantly 749 over full virtualization. However, when run without a hypervisor 750 the kernel is theoretically slower and slightly larger. 751 752config PARAVIRT_DEBUG 753 bool "paravirt-ops debugging" 754 depends on PARAVIRT && DEBUG_KERNEL 755 ---help--- 756 Enable to debug paravirt_ops internals. Specifically, BUG if 757 a paravirt_op is missing when it is called. 758 759config PARAVIRT_SPINLOCKS 760 bool "Paravirtualization layer for spinlocks" 761 depends on PARAVIRT && SMP 762 ---help--- 763 Paravirtualized spinlocks allow a pvops backend to replace the 764 spinlock implementation with something virtualization-friendly 765 (for example, block the virtual CPU rather than spinning). 766 767 It has a minimal impact on native kernels and gives a nice performance 768 benefit on paravirtualized KVM / Xen kernels. 769 770 If you are unsure how to answer this question, answer Y. 771 772config QUEUED_LOCK_STAT 773 bool "Paravirt queued spinlock statistics" 774 depends on PARAVIRT_SPINLOCKS && DEBUG_FS 775 ---help--- 776 Enable the collection of statistical data on the slowpath 777 behavior of paravirtualized queued spinlocks and report 778 them on debugfs. 779 780source "arch/x86/xen/Kconfig" 781 782config KVM_GUEST 783 bool "KVM Guest support (including kvmclock)" 784 depends on PARAVIRT 785 select PARAVIRT_CLOCK 786 default y 787 ---help--- 788 This option enables various optimizations for running under the KVM 789 hypervisor. It includes a paravirtualized clock, so that instead 790 of relying on a PIT (or probably other) emulation by the 791 underlying device model, the host provides the guest with 792 timing infrastructure such as time of day, and system time 793 794config KVM_DEBUG_FS 795 bool "Enable debug information for KVM Guests in debugfs" 796 depends on KVM_GUEST && DEBUG_FS 797 default n 798 ---help--- 799 This option enables collection of various statistics for KVM guest. 800 Statistics are displayed in debugfs filesystem. Enabling this option 801 may incur significant overhead. 802 803config PARAVIRT_TIME_ACCOUNTING 804 bool "Paravirtual steal time accounting" 805 depends on PARAVIRT 806 default n 807 ---help--- 808 Select this option to enable fine granularity task steal time 809 accounting. Time spent executing other tasks in parallel with 810 the current vCPU is discounted from the vCPU power. To account for 811 that, there can be a small performance impact. 812 813 If in doubt, say N here. 814 815config PARAVIRT_CLOCK 816 bool 817 818config JAILHOUSE_GUEST 819 bool "Jailhouse non-root cell support" 820 depends on X86_64 && PCI 821 select X86_PM_TIMER 822 ---help--- 823 This option allows to run Linux as guest in a Jailhouse non-root 824 cell. You can leave this option disabled if you only want to start 825 Jailhouse and run Linux afterwards in the root cell. 826 827endif #HYPERVISOR_GUEST 828 829config NO_BOOTMEM 830 def_bool y 831 832source "arch/x86/Kconfig.cpu" 833 834config HPET_TIMER 835 def_bool X86_64 836 prompt "HPET Timer Support" if X86_32 837 ---help--- 838 Use the IA-PC HPET (High Precision Event Timer) to manage 839 time in preference to the PIT and RTC, if a HPET is 840 present. 841 HPET is the next generation timer replacing legacy 8254s. 842 The HPET provides a stable time base on SMP 843 systems, unlike the TSC, but it is more expensive to access, 844 as it is off-chip. The interface used is documented 845 in the HPET spec, revision 1. 846 847 You can safely choose Y here. However, HPET will only be 848 activated if the platform and the BIOS support this feature. 849 Otherwise the 8254 will be used for timing services. 850 851 Choose N to continue using the legacy 8254 timer. 852 853config HPET_EMULATE_RTC 854 def_bool y 855 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 856 857config APB_TIMER 858 def_bool y if X86_INTEL_MID 859 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 860 select DW_APB_TIMER 861 depends on X86_INTEL_MID && SFI 862 help 863 APB timer is the replacement for 8254, HPET on X86 MID platforms. 864 The APBT provides a stable time base on SMP 865 systems, unlike the TSC, but it is more expensive to access, 866 as it is off-chip. APB timers are always running regardless of CPU 867 C states, they are used as per CPU clockevent device when possible. 868 869# Mark as expert because too many people got it wrong. 870# The code disables itself when not needed. 871config DMI 872 default y 873 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 874 bool "Enable DMI scanning" if EXPERT 875 ---help--- 876 Enabled scanning of DMI to identify machine quirks. Say Y 877 here unless you have verified that your setup is not 878 affected by entries in the DMI blacklist. Required by PNP 879 BIOS code. 880 881config GART_IOMMU 882 bool "Old AMD GART IOMMU support" 883 select IOMMU_HELPER 884 select SWIOTLB 885 depends on X86_64 && PCI && AMD_NB 886 ---help--- 887 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 888 GART based hardware IOMMUs. 889 890 The GART supports full DMA access for devices with 32-bit access 891 limitations, on systems with more than 3 GB. This is usually needed 892 for USB, sound, many IDE/SATA chipsets and some other devices. 893 894 Newer systems typically have a modern AMD IOMMU, supported via 895 the CONFIG_AMD_IOMMU=y config option. 896 897 In normal configurations this driver is only active when needed: 898 there's more than 3 GB of memory and the system contains a 899 32-bit limited device. 900 901 If unsure, say Y. 902 903config CALGARY_IOMMU 904 bool "IBM Calgary IOMMU support" 905 select IOMMU_HELPER 906 select SWIOTLB 907 depends on X86_64 && PCI 908 ---help--- 909 Support for hardware IOMMUs in IBM's xSeries x366 and x460 910 systems. Needed to run systems with more than 3GB of memory 911 properly with 32-bit PCI devices that do not support DAC 912 (Double Address Cycle). Calgary also supports bus level 913 isolation, where all DMAs pass through the IOMMU. This 914 prevents them from going anywhere except their intended 915 destination. This catches hard-to-find kernel bugs and 916 mis-behaving drivers and devices that do not use the DMA-API 917 properly to set up their DMA buffers. The IOMMU can be 918 turned off at boot time with the iommu=off parameter. 919 Normally the kernel will make the right choice by itself. 920 If unsure, say Y. 921 922config CALGARY_IOMMU_ENABLED_BY_DEFAULT 923 def_bool y 924 prompt "Should Calgary be enabled by default?" 925 depends on CALGARY_IOMMU 926 ---help--- 927 Should Calgary be enabled by default? if you choose 'y', Calgary 928 will be used (if it exists). If you choose 'n', Calgary will not be 929 used even if it exists. If you choose 'n' and would like to use 930 Calgary anyway, pass 'iommu=calgary' on the kernel command line. 931 If unsure, say Y. 932 933config MAXSMP 934 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 935 depends on X86_64 && SMP && DEBUG_KERNEL 936 select CPUMASK_OFFSTACK 937 ---help--- 938 Enable maximum number of CPUS and NUMA Nodes for this architecture. 939 If unsure, say N. 940 941# 942# The maximum number of CPUs supported: 943# 944# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 945# and which can be configured interactively in the 946# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 947# 948# The ranges are different on 32-bit and 64-bit kernels, depending on 949# hardware capabilities and scalability features of the kernel. 950# 951# ( If MAXSMP is enabled we just use the highest possible value and disable 952# interactive configuration. ) 953# 954 955config NR_CPUS_RANGE_BEGIN 956 int 957 default NR_CPUS_RANGE_END if MAXSMP 958 default 1 if !SMP 959 default 2 960 961config NR_CPUS_RANGE_END 962 int 963 depends on X86_32 964 default 64 if SMP && X86_BIGSMP 965 default 8 if SMP && !X86_BIGSMP 966 default 1 if !SMP 967 968config NR_CPUS_RANGE_END 969 int 970 depends on X86_64 971 default 8192 if SMP && ( MAXSMP || CPUMASK_OFFSTACK) 972 default 512 if SMP && (!MAXSMP && !CPUMASK_OFFSTACK) 973 default 1 if !SMP 974 975config NR_CPUS_DEFAULT 976 int 977 depends on X86_32 978 default 32 if X86_BIGSMP 979 default 8 if SMP 980 default 1 if !SMP 981 982config NR_CPUS_DEFAULT 983 int 984 depends on X86_64 985 default 8192 if MAXSMP 986 default 64 if SMP 987 default 1 if !SMP 988 989config NR_CPUS 990 int "Maximum number of CPUs" if SMP && !MAXSMP 991 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 992 default NR_CPUS_DEFAULT 993 ---help--- 994 This allows you to specify the maximum number of CPUs which this 995 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 996 supported value is 8192, otherwise the maximum value is 512. The 997 minimum value which makes sense is 2. 998 999 This is purely to save memory: each supported CPU adds about 8KB 1000 to the kernel image. 1001 1002config SCHED_SMT 1003 bool "SMT (Hyperthreading) scheduler support" 1004 depends on SMP 1005 ---help--- 1006 SMT scheduler support improves the CPU scheduler's decision making 1007 when dealing with Intel Pentium 4 chips with HyperThreading at a 1008 cost of slightly increased overhead in some places. If unsure say 1009 N here. 1010 1011config SCHED_MC 1012 def_bool y 1013 prompt "Multi-core scheduler support" 1014 depends on SMP 1015 ---help--- 1016 Multi-core scheduler support improves the CPU scheduler's decision 1017 making when dealing with multi-core CPU chips at a cost of slightly 1018 increased overhead in some places. If unsure say N here. 1019 1020config SCHED_MC_PRIO 1021 bool "CPU core priorities scheduler support" 1022 depends on SCHED_MC && CPU_SUP_INTEL 1023 select X86_INTEL_PSTATE 1024 select CPU_FREQ 1025 default y 1026 ---help--- 1027 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1028 core ordering determined at manufacturing time, which allows 1029 certain cores to reach higher turbo frequencies (when running 1030 single threaded workloads) than others. 1031 1032 Enabling this kernel feature teaches the scheduler about 1033 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1034 scheduler's CPU selection logic accordingly, so that higher 1035 overall system performance can be achieved. 1036 1037 This feature will have no effect on CPUs without this feature. 1038 1039 If unsure say Y here. 1040 1041source "kernel/Kconfig.preempt" 1042 1043config UP_LATE_INIT 1044 def_bool y 1045 depends on !SMP && X86_LOCAL_APIC 1046 1047config X86_UP_APIC 1048 bool "Local APIC support on uniprocessors" if !PCI_MSI 1049 default PCI_MSI 1050 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1051 ---help--- 1052 A local APIC (Advanced Programmable Interrupt Controller) is an 1053 integrated interrupt controller in the CPU. If you have a single-CPU 1054 system which has a processor with a local APIC, you can say Y here to 1055 enable and use it. If you say Y here even though your machine doesn't 1056 have a local APIC, then the kernel will still run with no slowdown at 1057 all. The local APIC supports CPU-generated self-interrupts (timer, 1058 performance counters), and the NMI watchdog which detects hard 1059 lockups. 1060 1061config X86_UP_IOAPIC 1062 bool "IO-APIC support on uniprocessors" 1063 depends on X86_UP_APIC 1064 ---help--- 1065 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1066 SMP-capable replacement for PC-style interrupt controllers. Most 1067 SMP systems and many recent uniprocessor systems have one. 1068 1069 If you have a single-CPU system with an IO-APIC, you can say Y here 1070 to use it. If you say Y here even though your machine doesn't have 1071 an IO-APIC, then the kernel will still run with no slowdown at all. 1072 1073config X86_LOCAL_APIC 1074 def_bool y 1075 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1076 select IRQ_DOMAIN_HIERARCHY 1077 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1078 1079config X86_IO_APIC 1080 def_bool y 1081 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1082 1083config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1084 bool "Reroute for broken boot IRQs" 1085 depends on X86_IO_APIC 1086 ---help--- 1087 This option enables a workaround that fixes a source of 1088 spurious interrupts. This is recommended when threaded 1089 interrupt handling is used on systems where the generation of 1090 superfluous "boot interrupts" cannot be disabled. 1091 1092 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1093 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1094 kernel does during interrupt handling). On chipsets where this 1095 boot IRQ generation cannot be disabled, this workaround keeps 1096 the original IRQ line masked so that only the equivalent "boot 1097 IRQ" is delivered to the CPUs. The workaround also tells the 1098 kernel to set up the IRQ handler on the boot IRQ line. In this 1099 way only one interrupt is delivered to the kernel. Otherwise 1100 the spurious second interrupt may cause the kernel to bring 1101 down (vital) interrupt lines. 1102 1103 Only affects "broken" chipsets. Interrupt sharing may be 1104 increased on these systems. 1105 1106config X86_MCE 1107 bool "Machine Check / overheating reporting" 1108 select GENERIC_ALLOCATOR 1109 default y 1110 ---help--- 1111 Machine Check support allows the processor to notify the 1112 kernel if it detects a problem (e.g. overheating, data corruption). 1113 The action the kernel takes depends on the severity of the problem, 1114 ranging from warning messages to halting the machine. 1115 1116config X86_MCELOG_LEGACY 1117 bool "Support for deprecated /dev/mcelog character device" 1118 depends on X86_MCE 1119 ---help--- 1120 Enable support for /dev/mcelog which is needed by the old mcelog 1121 userspace logging daemon. Consider switching to the new generation 1122 rasdaemon solution. 1123 1124config X86_MCE_INTEL 1125 def_bool y 1126 prompt "Intel MCE features" 1127 depends on X86_MCE && X86_LOCAL_APIC 1128 ---help--- 1129 Additional support for intel specific MCE features such as 1130 the thermal monitor. 1131 1132config X86_MCE_AMD 1133 def_bool y 1134 prompt "AMD MCE features" 1135 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1136 ---help--- 1137 Additional support for AMD specific MCE features such as 1138 the DRAM Error Threshold. 1139 1140config X86_ANCIENT_MCE 1141 bool "Support for old Pentium 5 / WinChip machine checks" 1142 depends on X86_32 && X86_MCE 1143 ---help--- 1144 Include support for machine check handling on old Pentium 5 or WinChip 1145 systems. These typically need to be enabled explicitly on the command 1146 line. 1147 1148config X86_MCE_THRESHOLD 1149 depends on X86_MCE_AMD || X86_MCE_INTEL 1150 def_bool y 1151 1152config X86_MCE_INJECT 1153 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1154 tristate "Machine check injector support" 1155 ---help--- 1156 Provide support for injecting machine checks for testing purposes. 1157 If you don't know what a machine check is and you don't do kernel 1158 QA it is safe to say n. 1159 1160config X86_THERMAL_VECTOR 1161 def_bool y 1162 depends on X86_MCE_INTEL 1163 1164source "arch/x86/events/Kconfig" 1165 1166config X86_LEGACY_VM86 1167 bool "Legacy VM86 support" 1168 default n 1169 depends on X86_32 1170 ---help--- 1171 This option allows user programs to put the CPU into V8086 1172 mode, which is an 80286-era approximation of 16-bit real mode. 1173 1174 Some very old versions of X and/or vbetool require this option 1175 for user mode setting. Similarly, DOSEMU will use it if 1176 available to accelerate real mode DOS programs. However, any 1177 recent version of DOSEMU, X, or vbetool should be fully 1178 functional even without kernel VM86 support, as they will all 1179 fall back to software emulation. Nevertheless, if you are using 1180 a 16-bit DOS program where 16-bit performance matters, vm86 1181 mode might be faster than emulation and you might want to 1182 enable this option. 1183 1184 Note that any app that works on a 64-bit kernel is unlikely to 1185 need this option, as 64-bit kernels don't, and can't, support 1186 V8086 mode. This option is also unrelated to 16-bit protected 1187 mode and is not needed to run most 16-bit programs under Wine. 1188 1189 Enabling this option increases the complexity of the kernel 1190 and slows down exception handling a tiny bit. 1191 1192 If unsure, say N here. 1193 1194config VM86 1195 bool 1196 default X86_LEGACY_VM86 1197 1198config X86_16BIT 1199 bool "Enable support for 16-bit segments" if EXPERT 1200 default y 1201 depends on MODIFY_LDT_SYSCALL 1202 ---help--- 1203 This option is required by programs like Wine to run 16-bit 1204 protected mode legacy code on x86 processors. Disabling 1205 this option saves about 300 bytes on i386, or around 6K text 1206 plus 16K runtime memory on x86-64, 1207 1208config X86_ESPFIX32 1209 def_bool y 1210 depends on X86_16BIT && X86_32 1211 1212config X86_ESPFIX64 1213 def_bool y 1214 depends on X86_16BIT && X86_64 1215 1216config X86_VSYSCALL_EMULATION 1217 bool "Enable vsyscall emulation" if EXPERT 1218 default y 1219 depends on X86_64 1220 ---help--- 1221 This enables emulation of the legacy vsyscall page. Disabling 1222 it is roughly equivalent to booting with vsyscall=none, except 1223 that it will also disable the helpful warning if a program 1224 tries to use a vsyscall. With this option set to N, offending 1225 programs will just segfault, citing addresses of the form 1226 0xffffffffff600?00. 1227 1228 This option is required by many programs built before 2013, and 1229 care should be used even with newer programs if set to N. 1230 1231 Disabling this option saves about 7K of kernel size and 1232 possibly 4K of additional runtime pagetable memory. 1233 1234config TOSHIBA 1235 tristate "Toshiba Laptop support" 1236 depends on X86_32 1237 ---help--- 1238 This adds a driver to safely access the System Management Mode of 1239 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1240 not work on models with a Phoenix BIOS. The System Management Mode 1241 is used to set the BIOS and power saving options on Toshiba portables. 1242 1243 For information on utilities to make use of this driver see the 1244 Toshiba Linux utilities web site at: 1245 <http://www.buzzard.org.uk/toshiba/>. 1246 1247 Say Y if you intend to run this kernel on a Toshiba portable. 1248 Say N otherwise. 1249 1250config I8K 1251 tristate "Dell i8k legacy laptop support" 1252 select HWMON 1253 select SENSORS_DELL_SMM 1254 ---help--- 1255 This option enables legacy /proc/i8k userspace interface in hwmon 1256 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1257 temperature and allows controlling fan speeds of Dell laptops via 1258 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1259 it reports also power and hotkey status. For fan speed control is 1260 needed userspace package i8kutils. 1261 1262 Say Y if you intend to run this kernel on old Dell laptops or want to 1263 use userspace package i8kutils. 1264 Say N otherwise. 1265 1266config X86_REBOOTFIXUPS 1267 bool "Enable X86 board specific fixups for reboot" 1268 depends on X86_32 1269 ---help--- 1270 This enables chipset and/or board specific fixups to be done 1271 in order to get reboot to work correctly. This is only needed on 1272 some combinations of hardware and BIOS. The symptom, for which 1273 this config is intended, is when reboot ends with a stalled/hung 1274 system. 1275 1276 Currently, the only fixup is for the Geode machines using 1277 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1278 1279 Say Y if you want to enable the fixup. Currently, it's safe to 1280 enable this option even if you don't need it. 1281 Say N otherwise. 1282 1283config MICROCODE 1284 bool "CPU microcode loading support" 1285 default y 1286 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1287 select FW_LOADER 1288 ---help--- 1289 If you say Y here, you will be able to update the microcode on 1290 Intel and AMD processors. The Intel support is for the IA32 family, 1291 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1292 AMD support is for families 0x10 and later. You will obviously need 1293 the actual microcode binary data itself which is not shipped with 1294 the Linux kernel. 1295 1296 The preferred method to load microcode from a detached initrd is described 1297 in Documentation/x86/microcode.txt. For that you need to enable 1298 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1299 initrd for microcode blobs. 1300 1301 In addition, you can build the microcode into the kernel. For that you 1302 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1303 config option. 1304 1305config MICROCODE_INTEL 1306 bool "Intel microcode loading support" 1307 depends on MICROCODE 1308 default MICROCODE 1309 select FW_LOADER 1310 ---help--- 1311 This options enables microcode patch loading support for Intel 1312 processors. 1313 1314 For the current Intel microcode data package go to 1315 <https://downloadcenter.intel.com> and search for 1316 'Linux Processor Microcode Data File'. 1317 1318config MICROCODE_AMD 1319 bool "AMD microcode loading support" 1320 depends on MICROCODE 1321 select FW_LOADER 1322 ---help--- 1323 If you select this option, microcode patch loading support for AMD 1324 processors will be enabled. 1325 1326config MICROCODE_OLD_INTERFACE 1327 def_bool y 1328 depends on MICROCODE 1329 1330config X86_MSR 1331 tristate "/dev/cpu/*/msr - Model-specific register support" 1332 ---help--- 1333 This device gives privileged processes access to the x86 1334 Model-Specific Registers (MSRs). It is a character device with 1335 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1336 MSR accesses are directed to a specific CPU on multi-processor 1337 systems. 1338 1339config X86_CPUID 1340 tristate "/dev/cpu/*/cpuid - CPU information support" 1341 ---help--- 1342 This device gives processes access to the x86 CPUID instruction to 1343 be executed on a specific processor. It is a character device 1344 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1345 /dev/cpu/31/cpuid. 1346 1347choice 1348 prompt "High Memory Support" 1349 default HIGHMEM4G 1350 depends on X86_32 1351 1352config NOHIGHMEM 1353 bool "off" 1354 ---help--- 1355 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1356 However, the address space of 32-bit x86 processors is only 4 1357 Gigabytes large. That means that, if you have a large amount of 1358 physical memory, not all of it can be "permanently mapped" by the 1359 kernel. The physical memory that's not permanently mapped is called 1360 "high memory". 1361 1362 If you are compiling a kernel which will never run on a machine with 1363 more than 1 Gigabyte total physical RAM, answer "off" here (default 1364 choice and suitable for most users). This will result in a "3GB/1GB" 1365 split: 3GB are mapped so that each process sees a 3GB virtual memory 1366 space and the remaining part of the 4GB virtual memory space is used 1367 by the kernel to permanently map as much physical memory as 1368 possible. 1369 1370 If the machine has between 1 and 4 Gigabytes physical RAM, then 1371 answer "4GB" here. 1372 1373 If more than 4 Gigabytes is used then answer "64GB" here. This 1374 selection turns Intel PAE (Physical Address Extension) mode on. 1375 PAE implements 3-level paging on IA32 processors. PAE is fully 1376 supported by Linux, PAE mode is implemented on all recent Intel 1377 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1378 then the kernel will not boot on CPUs that don't support PAE! 1379 1380 The actual amount of total physical memory will either be 1381 auto detected or can be forced by using a kernel command line option 1382 such as "mem=256M". (Try "man bootparam" or see the documentation of 1383 your boot loader (lilo or loadlin) about how to pass options to the 1384 kernel at boot time.) 1385 1386 If unsure, say "off". 1387 1388config HIGHMEM4G 1389 bool "4GB" 1390 ---help--- 1391 Select this if you have a 32-bit processor and between 1 and 4 1392 gigabytes of physical RAM. 1393 1394config HIGHMEM64G 1395 bool "64GB" 1396 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1397 select X86_PAE 1398 ---help--- 1399 Select this if you have a 32-bit processor and more than 4 1400 gigabytes of physical RAM. 1401 1402endchoice 1403 1404choice 1405 prompt "Memory split" if EXPERT 1406 default VMSPLIT_3G 1407 depends on X86_32 1408 ---help--- 1409 Select the desired split between kernel and user memory. 1410 1411 If the address range available to the kernel is less than the 1412 physical memory installed, the remaining memory will be available 1413 as "high memory". Accessing high memory is a little more costly 1414 than low memory, as it needs to be mapped into the kernel first. 1415 Note that increasing the kernel address space limits the range 1416 available to user programs, making the address space there 1417 tighter. Selecting anything other than the default 3G/1G split 1418 will also likely make your kernel incompatible with binary-only 1419 kernel modules. 1420 1421 If you are not absolutely sure what you are doing, leave this 1422 option alone! 1423 1424 config VMSPLIT_3G 1425 bool "3G/1G user/kernel split" 1426 config VMSPLIT_3G_OPT 1427 depends on !X86_PAE 1428 bool "3G/1G user/kernel split (for full 1G low memory)" 1429 config VMSPLIT_2G 1430 bool "2G/2G user/kernel split" 1431 config VMSPLIT_2G_OPT 1432 depends on !X86_PAE 1433 bool "2G/2G user/kernel split (for full 2G low memory)" 1434 config VMSPLIT_1G 1435 bool "1G/3G user/kernel split" 1436endchoice 1437 1438config PAGE_OFFSET 1439 hex 1440 default 0xB0000000 if VMSPLIT_3G_OPT 1441 default 0x80000000 if VMSPLIT_2G 1442 default 0x78000000 if VMSPLIT_2G_OPT 1443 default 0x40000000 if VMSPLIT_1G 1444 default 0xC0000000 1445 depends on X86_32 1446 1447config HIGHMEM 1448 def_bool y 1449 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1450 1451config X86_PAE 1452 bool "PAE (Physical Address Extension) Support" 1453 depends on X86_32 && !HIGHMEM4G 1454 select PHYS_ADDR_T_64BIT 1455 select SWIOTLB 1456 ---help--- 1457 PAE is required for NX support, and furthermore enables 1458 larger swapspace support for non-overcommit purposes. It 1459 has the cost of more pagetable lookup overhead, and also 1460 consumes more pagetable space per process. 1461 1462config X86_5LEVEL 1463 bool "Enable 5-level page tables support" 1464 select DYNAMIC_MEMORY_LAYOUT 1465 select SPARSEMEM_VMEMMAP 1466 depends on X86_64 1467 ---help--- 1468 5-level paging enables access to larger address space: 1469 upto 128 PiB of virtual address space and 4 PiB of 1470 physical address space. 1471 1472 It will be supported by future Intel CPUs. 1473 1474 A kernel with the option enabled can be booted on machines that 1475 support 4- or 5-level paging. 1476 1477 See Documentation/x86/x86_64/5level-paging.txt for more 1478 information. 1479 1480 Say N if unsure. 1481 1482config X86_DIRECT_GBPAGES 1483 def_bool y 1484 depends on X86_64 && !DEBUG_PAGEALLOC 1485 ---help--- 1486 Certain kernel features effectively disable kernel 1487 linear 1 GB mappings (even if the CPU otherwise 1488 supports them), so don't confuse the user by printing 1489 that we have them enabled. 1490 1491config ARCH_HAS_MEM_ENCRYPT 1492 def_bool y 1493 1494config AMD_MEM_ENCRYPT 1495 bool "AMD Secure Memory Encryption (SME) support" 1496 depends on X86_64 && CPU_SUP_AMD 1497 ---help--- 1498 Say yes to enable support for the encryption of system memory. 1499 This requires an AMD processor that supports Secure Memory 1500 Encryption (SME). 1501 1502config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1503 bool "Activate AMD Secure Memory Encryption (SME) by default" 1504 default y 1505 depends on AMD_MEM_ENCRYPT 1506 ---help--- 1507 Say yes to have system memory encrypted by default if running on 1508 an AMD processor that supports Secure Memory Encryption (SME). 1509 1510 If set to Y, then the encryption of system memory can be 1511 deactivated with the mem_encrypt=off command line option. 1512 1513 If set to N, then the encryption of system memory can be 1514 activated with the mem_encrypt=on command line option. 1515 1516config ARCH_USE_MEMREMAP_PROT 1517 def_bool y 1518 depends on AMD_MEM_ENCRYPT 1519 1520# Common NUMA Features 1521config NUMA 1522 bool "Numa Memory Allocation and Scheduler Support" 1523 depends on SMP 1524 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1525 default y if X86_BIGSMP 1526 ---help--- 1527 Enable NUMA (Non Uniform Memory Access) support. 1528 1529 The kernel will try to allocate memory used by a CPU on the 1530 local memory controller of the CPU and add some more 1531 NUMA awareness to the kernel. 1532 1533 For 64-bit this is recommended if the system is Intel Core i7 1534 (or later), AMD Opteron, or EM64T NUMA. 1535 1536 For 32-bit this is only needed if you boot a 32-bit 1537 kernel on a 64-bit NUMA platform. 1538 1539 Otherwise, you should say N. 1540 1541config AMD_NUMA 1542 def_bool y 1543 prompt "Old style AMD Opteron NUMA detection" 1544 depends on X86_64 && NUMA && PCI 1545 ---help--- 1546 Enable AMD NUMA node topology detection. You should say Y here if 1547 you have a multi processor AMD system. This uses an old method to 1548 read the NUMA configuration directly from the builtin Northbridge 1549 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1550 which also takes priority if both are compiled in. 1551 1552config X86_64_ACPI_NUMA 1553 def_bool y 1554 prompt "ACPI NUMA detection" 1555 depends on X86_64 && NUMA && ACPI && PCI 1556 select ACPI_NUMA 1557 ---help--- 1558 Enable ACPI SRAT based node topology detection. 1559 1560# Some NUMA nodes have memory ranges that span 1561# other nodes. Even though a pfn is valid and 1562# between a node's start and end pfns, it may not 1563# reside on that node. See memmap_init_zone() 1564# for details. 1565config NODES_SPAN_OTHER_NODES 1566 def_bool y 1567 depends on X86_64_ACPI_NUMA 1568 1569config NUMA_EMU 1570 bool "NUMA emulation" 1571 depends on NUMA 1572 ---help--- 1573 Enable NUMA emulation. A flat machine will be split 1574 into virtual nodes when booted with "numa=fake=N", where N is the 1575 number of nodes. This is only useful for debugging. 1576 1577config NODES_SHIFT 1578 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1579 range 1 10 1580 default "10" if MAXSMP 1581 default "6" if X86_64 1582 default "3" 1583 depends on NEED_MULTIPLE_NODES 1584 ---help--- 1585 Specify the maximum number of NUMA Nodes available on the target 1586 system. Increases memory reserved to accommodate various tables. 1587 1588config ARCH_HAVE_MEMORY_PRESENT 1589 def_bool y 1590 depends on X86_32 && DISCONTIGMEM 1591 1592config ARCH_FLATMEM_ENABLE 1593 def_bool y 1594 depends on X86_32 && !NUMA 1595 1596config ARCH_DISCONTIGMEM_ENABLE 1597 def_bool y 1598 depends on NUMA && X86_32 1599 1600config ARCH_DISCONTIGMEM_DEFAULT 1601 def_bool y 1602 depends on NUMA && X86_32 1603 1604config ARCH_SPARSEMEM_ENABLE 1605 def_bool y 1606 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1607 select SPARSEMEM_STATIC if X86_32 1608 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1609 1610config ARCH_SPARSEMEM_DEFAULT 1611 def_bool y 1612 depends on X86_64 1613 1614config ARCH_SELECT_MEMORY_MODEL 1615 def_bool y 1616 depends on ARCH_SPARSEMEM_ENABLE 1617 1618config ARCH_MEMORY_PROBE 1619 bool "Enable sysfs memory/probe interface" 1620 depends on X86_64 && MEMORY_HOTPLUG 1621 help 1622 This option enables a sysfs memory/probe interface for testing. 1623 See Documentation/memory-hotplug.txt for more information. 1624 If you are unsure how to answer this question, answer N. 1625 1626config ARCH_PROC_KCORE_TEXT 1627 def_bool y 1628 depends on X86_64 && PROC_KCORE 1629 1630config ILLEGAL_POINTER_VALUE 1631 hex 1632 default 0 if X86_32 1633 default 0xdead000000000000 if X86_64 1634 1635source "mm/Kconfig" 1636 1637config X86_PMEM_LEGACY_DEVICE 1638 bool 1639 1640config X86_PMEM_LEGACY 1641 tristate "Support non-standard NVDIMMs and ADR protected memory" 1642 depends on PHYS_ADDR_T_64BIT 1643 depends on BLK_DEV 1644 select X86_PMEM_LEGACY_DEVICE 1645 select LIBNVDIMM 1646 help 1647 Treat memory marked using the non-standard e820 type of 12 as used 1648 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1649 The kernel will offer these regions to the 'pmem' driver so 1650 they can be used for persistent storage. 1651 1652 Say Y if unsure. 1653 1654config HIGHPTE 1655 bool "Allocate 3rd-level pagetables from highmem" 1656 depends on HIGHMEM 1657 ---help--- 1658 The VM uses one page table entry for each page of physical memory. 1659 For systems with a lot of RAM, this can be wasteful of precious 1660 low memory. Setting this option will put user-space page table 1661 entries in high memory. 1662 1663config X86_CHECK_BIOS_CORRUPTION 1664 bool "Check for low memory corruption" 1665 ---help--- 1666 Periodically check for memory corruption in low memory, which 1667 is suspected to be caused by BIOS. Even when enabled in the 1668 configuration, it is disabled at runtime. Enable it by 1669 setting "memory_corruption_check=1" on the kernel command 1670 line. By default it scans the low 64k of memory every 60 1671 seconds; see the memory_corruption_check_size and 1672 memory_corruption_check_period parameters in 1673 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1674 1675 When enabled with the default parameters, this option has 1676 almost no overhead, as it reserves a relatively small amount 1677 of memory and scans it infrequently. It both detects corruption 1678 and prevents it from affecting the running system. 1679 1680 It is, however, intended as a diagnostic tool; if repeatable 1681 BIOS-originated corruption always affects the same memory, 1682 you can use memmap= to prevent the kernel from using that 1683 memory. 1684 1685config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1686 bool "Set the default setting of memory_corruption_check" 1687 depends on X86_CHECK_BIOS_CORRUPTION 1688 default y 1689 ---help--- 1690 Set whether the default state of memory_corruption_check is 1691 on or off. 1692 1693config X86_RESERVE_LOW 1694 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1695 default 64 1696 range 4 640 1697 ---help--- 1698 Specify the amount of low memory to reserve for the BIOS. 1699 1700 The first page contains BIOS data structures that the kernel 1701 must not use, so that page must always be reserved. 1702 1703 By default we reserve the first 64K of physical RAM, as a 1704 number of BIOSes are known to corrupt that memory range 1705 during events such as suspend/resume or monitor cable 1706 insertion, so it must not be used by the kernel. 1707 1708 You can set this to 4 if you are absolutely sure that you 1709 trust the BIOS to get all its memory reservations and usages 1710 right. If you know your BIOS have problems beyond the 1711 default 64K area, you can set this to 640 to avoid using the 1712 entire low memory range. 1713 1714 If you have doubts about the BIOS (e.g. suspend/resume does 1715 not work or there's kernel crashes after certain hardware 1716 hotplug events) then you might want to enable 1717 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1718 typical corruption patterns. 1719 1720 Leave this to the default value of 64 if you are unsure. 1721 1722config MATH_EMULATION 1723 bool 1724 depends on MODIFY_LDT_SYSCALL 1725 prompt "Math emulation" if X86_32 1726 ---help--- 1727 Linux can emulate a math coprocessor (used for floating point 1728 operations) if you don't have one. 486DX and Pentium processors have 1729 a math coprocessor built in, 486SX and 386 do not, unless you added 1730 a 487DX or 387, respectively. (The messages during boot time can 1731 give you some hints here ["man dmesg"].) Everyone needs either a 1732 coprocessor or this emulation. 1733 1734 If you don't have a math coprocessor, you need to say Y here; if you 1735 say Y here even though you have a coprocessor, the coprocessor will 1736 be used nevertheless. (This behavior can be changed with the kernel 1737 command line option "no387", which comes handy if your coprocessor 1738 is broken. Try "man bootparam" or see the documentation of your boot 1739 loader (lilo or loadlin) about how to pass options to the kernel at 1740 boot time.) This means that it is a good idea to say Y here if you 1741 intend to use this kernel on different machines. 1742 1743 More information about the internals of the Linux math coprocessor 1744 emulation can be found in <file:arch/x86/math-emu/README>. 1745 1746 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1747 kernel, it won't hurt. 1748 1749config MTRR 1750 def_bool y 1751 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1752 ---help--- 1753 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1754 the Memory Type Range Registers (MTRRs) may be used to control 1755 processor access to memory ranges. This is most useful if you have 1756 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1757 allows bus write transfers to be combined into a larger transfer 1758 before bursting over the PCI/AGP bus. This can increase performance 1759 of image write operations 2.5 times or more. Saying Y here creates a 1760 /proc/mtrr file which may be used to manipulate your processor's 1761 MTRRs. Typically the X server should use this. 1762 1763 This code has a reasonably generic interface so that similar 1764 control registers on other processors can be easily supported 1765 as well: 1766 1767 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1768 Registers (ARRs) which provide a similar functionality to MTRRs. For 1769 these, the ARRs are used to emulate the MTRRs. 1770 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1771 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1772 write-combining. All of these processors are supported by this code 1773 and it makes sense to say Y here if you have one of them. 1774 1775 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1776 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1777 can lead to all sorts of problems, so it's good to say Y here. 1778 1779 You can safely say Y even if your machine doesn't have MTRRs, you'll 1780 just add about 9 KB to your kernel. 1781 1782 See <file:Documentation/x86/mtrr.txt> for more information. 1783 1784config MTRR_SANITIZER 1785 def_bool y 1786 prompt "MTRR cleanup support" 1787 depends on MTRR 1788 ---help--- 1789 Convert MTRR layout from continuous to discrete, so X drivers can 1790 add writeback entries. 1791 1792 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1793 The largest mtrr entry size for a continuous block can be set with 1794 mtrr_chunk_size. 1795 1796 If unsure, say Y. 1797 1798config MTRR_SANITIZER_ENABLE_DEFAULT 1799 int "MTRR cleanup enable value (0-1)" 1800 range 0 1 1801 default "0" 1802 depends on MTRR_SANITIZER 1803 ---help--- 1804 Enable mtrr cleanup default value 1805 1806config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1807 int "MTRR cleanup spare reg num (0-7)" 1808 range 0 7 1809 default "1" 1810 depends on MTRR_SANITIZER 1811 ---help--- 1812 mtrr cleanup spare entries default, it can be changed via 1813 mtrr_spare_reg_nr=N on the kernel command line. 1814 1815config X86_PAT 1816 def_bool y 1817 prompt "x86 PAT support" if EXPERT 1818 depends on MTRR 1819 ---help--- 1820 Use PAT attributes to setup page level cache control. 1821 1822 PATs are the modern equivalents of MTRRs and are much more 1823 flexible than MTRRs. 1824 1825 Say N here if you see bootup problems (boot crash, boot hang, 1826 spontaneous reboots) or a non-working video driver. 1827 1828 If unsure, say Y. 1829 1830config ARCH_USES_PG_UNCACHED 1831 def_bool y 1832 depends on X86_PAT 1833 1834config ARCH_RANDOM 1835 def_bool y 1836 prompt "x86 architectural random number generator" if EXPERT 1837 ---help--- 1838 Enable the x86 architectural RDRAND instruction 1839 (Intel Bull Mountain technology) to generate random numbers. 1840 If supported, this is a high bandwidth, cryptographically 1841 secure hardware random number generator. 1842 1843config X86_SMAP 1844 def_bool y 1845 prompt "Supervisor Mode Access Prevention" if EXPERT 1846 ---help--- 1847 Supervisor Mode Access Prevention (SMAP) is a security 1848 feature in newer Intel processors. There is a small 1849 performance cost if this enabled and turned on; there is 1850 also a small increase in the kernel size if this is enabled. 1851 1852 If unsure, say Y. 1853 1854config X86_INTEL_UMIP 1855 def_bool y 1856 depends on CPU_SUP_INTEL 1857 prompt "Intel User Mode Instruction Prevention" if EXPERT 1858 ---help--- 1859 The User Mode Instruction Prevention (UMIP) is a security 1860 feature in newer Intel processors. If enabled, a general 1861 protection fault is issued if the SGDT, SLDT, SIDT, SMSW 1862 or STR instructions are executed in user mode. These instructions 1863 unnecessarily expose information about the hardware state. 1864 1865 The vast majority of applications do not use these instructions. 1866 For the very few that do, software emulation is provided in 1867 specific cases in protected and virtual-8086 modes. Emulated 1868 results are dummy. 1869 1870config X86_INTEL_MPX 1871 prompt "Intel MPX (Memory Protection Extensions)" 1872 def_bool n 1873 # Note: only available in 64-bit mode due to VMA flags shortage 1874 depends on CPU_SUP_INTEL && X86_64 1875 select ARCH_USES_HIGH_VMA_FLAGS 1876 ---help--- 1877 MPX provides hardware features that can be used in 1878 conjunction with compiler-instrumented code to check 1879 memory references. It is designed to detect buffer 1880 overflow or underflow bugs. 1881 1882 This option enables running applications which are 1883 instrumented or otherwise use MPX. It does not use MPX 1884 itself inside the kernel or to protect the kernel 1885 against bad memory references. 1886 1887 Enabling this option will make the kernel larger: 1888 ~8k of kernel text and 36 bytes of data on a 64-bit 1889 defconfig. It adds a long to the 'mm_struct' which 1890 will increase the kernel memory overhead of each 1891 process and adds some branches to paths used during 1892 exec() and munmap(). 1893 1894 For details, see Documentation/x86/intel_mpx.txt 1895 1896 If unsure, say N. 1897 1898config X86_INTEL_MEMORY_PROTECTION_KEYS 1899 prompt "Intel Memory Protection Keys" 1900 def_bool y 1901 # Note: only available in 64-bit mode 1902 depends on CPU_SUP_INTEL && X86_64 1903 select ARCH_USES_HIGH_VMA_FLAGS 1904 select ARCH_HAS_PKEYS 1905 ---help--- 1906 Memory Protection Keys provides a mechanism for enforcing 1907 page-based protections, but without requiring modification of the 1908 page tables when an application changes protection domains. 1909 1910 For details, see Documentation/x86/protection-keys.txt 1911 1912 If unsure, say y. 1913 1914config EFI 1915 bool "EFI runtime service support" 1916 depends on ACPI 1917 select UCS2_STRING 1918 select EFI_RUNTIME_WRAPPERS 1919 ---help--- 1920 This enables the kernel to use EFI runtime services that are 1921 available (such as the EFI variable services). 1922 1923 This option is only useful on systems that have EFI firmware. 1924 In addition, you should use the latest ELILO loader available 1925 at <http://elilo.sourceforge.net> in order to take advantage 1926 of EFI runtime services. However, even with this option, the 1927 resultant kernel should continue to boot on existing non-EFI 1928 platforms. 1929 1930config EFI_STUB 1931 bool "EFI stub support" 1932 depends on EFI && !X86_USE_3DNOW 1933 select RELOCATABLE 1934 ---help--- 1935 This kernel feature allows a bzImage to be loaded directly 1936 by EFI firmware without the use of a bootloader. 1937 1938 See Documentation/efi-stub.txt for more information. 1939 1940config EFI_MIXED 1941 bool "EFI mixed-mode support" 1942 depends on EFI_STUB && X86_64 1943 ---help--- 1944 Enabling this feature allows a 64-bit kernel to be booted 1945 on a 32-bit firmware, provided that your CPU supports 64-bit 1946 mode. 1947 1948 Note that it is not possible to boot a mixed-mode enabled 1949 kernel via the EFI boot stub - a bootloader that supports 1950 the EFI handover protocol must be used. 1951 1952 If unsure, say N. 1953 1954config SECCOMP 1955 def_bool y 1956 prompt "Enable seccomp to safely compute untrusted bytecode" 1957 ---help--- 1958 This kernel feature is useful for number crunching applications 1959 that may need to compute untrusted bytecode during their 1960 execution. By using pipes or other transports made available to 1961 the process as file descriptors supporting the read/write 1962 syscalls, it's possible to isolate those applications in 1963 their own address space using seccomp. Once seccomp is 1964 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 1965 and the task is only allowed to execute a few safe syscalls 1966 defined by each seccomp mode. 1967 1968 If unsure, say Y. Only embedded should say N here. 1969 1970source kernel/Kconfig.hz 1971 1972config KEXEC 1973 bool "kexec system call" 1974 select KEXEC_CORE 1975 ---help--- 1976 kexec is a system call that implements the ability to shutdown your 1977 current kernel, and to start another kernel. It is like a reboot 1978 but it is independent of the system firmware. And like a reboot 1979 you can start any kernel with it, not just Linux. 1980 1981 The name comes from the similarity to the exec system call. 1982 1983 It is an ongoing process to be certain the hardware in a machine 1984 is properly shutdown, so do not be surprised if this code does not 1985 initially work for you. As of this writing the exact hardware 1986 interface is strongly in flux, so no good recommendation can be 1987 made. 1988 1989config KEXEC_FILE 1990 bool "kexec file based system call" 1991 select KEXEC_CORE 1992 select BUILD_BIN2C 1993 depends on X86_64 1994 depends on CRYPTO=y 1995 depends on CRYPTO_SHA256=y 1996 ---help--- 1997 This is new version of kexec system call. This system call is 1998 file based and takes file descriptors as system call argument 1999 for kernel and initramfs as opposed to list of segments as 2000 accepted by previous system call. 2001 2002config ARCH_HAS_KEXEC_PURGATORY 2003 def_bool KEXEC_FILE 2004 2005config KEXEC_VERIFY_SIG 2006 bool "Verify kernel signature during kexec_file_load() syscall" 2007 depends on KEXEC_FILE 2008 ---help--- 2009 This option makes kernel signature verification mandatory for 2010 the kexec_file_load() syscall. 2011 2012 In addition to that option, you need to enable signature 2013 verification for the corresponding kernel image type being 2014 loaded in order for this to work. 2015 2016config KEXEC_BZIMAGE_VERIFY_SIG 2017 bool "Enable bzImage signature verification support" 2018 depends on KEXEC_VERIFY_SIG 2019 depends on SIGNED_PE_FILE_VERIFICATION 2020 select SYSTEM_TRUSTED_KEYRING 2021 ---help--- 2022 Enable bzImage signature verification support. 2023 2024config CRASH_DUMP 2025 bool "kernel crash dumps" 2026 depends on X86_64 || (X86_32 && HIGHMEM) 2027 ---help--- 2028 Generate crash dump after being started by kexec. 2029 This should be normally only set in special crash dump kernels 2030 which are loaded in the main kernel with kexec-tools into 2031 a specially reserved region and then later executed after 2032 a crash by kdump/kexec. The crash dump kernel must be compiled 2033 to a memory address not used by the main kernel or BIOS using 2034 PHYSICAL_START, or it must be built as a relocatable image 2035 (CONFIG_RELOCATABLE=y). 2036 For more details see Documentation/kdump/kdump.txt 2037 2038config KEXEC_JUMP 2039 bool "kexec jump" 2040 depends on KEXEC && HIBERNATION 2041 ---help--- 2042 Jump between original kernel and kexeced kernel and invoke 2043 code in physical address mode via KEXEC 2044 2045config PHYSICAL_START 2046 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2047 default "0x1000000" 2048 ---help--- 2049 This gives the physical address where the kernel is loaded. 2050 2051 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2052 bzImage will decompress itself to above physical address and 2053 run from there. Otherwise, bzImage will run from the address where 2054 it has been loaded by the boot loader and will ignore above physical 2055 address. 2056 2057 In normal kdump cases one does not have to set/change this option 2058 as now bzImage can be compiled as a completely relocatable image 2059 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2060 address. This option is mainly useful for the folks who don't want 2061 to use a bzImage for capturing the crash dump and want to use a 2062 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2063 to be specifically compiled to run from a specific memory area 2064 (normally a reserved region) and this option comes handy. 2065 2066 So if you are using bzImage for capturing the crash dump, 2067 leave the value here unchanged to 0x1000000 and set 2068 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2069 for capturing the crash dump change this value to start of 2070 the reserved region. In other words, it can be set based on 2071 the "X" value as specified in the "crashkernel=YM@XM" 2072 command line boot parameter passed to the panic-ed 2073 kernel. Please take a look at Documentation/kdump/kdump.txt 2074 for more details about crash dumps. 2075 2076 Usage of bzImage for capturing the crash dump is recommended as 2077 one does not have to build two kernels. Same kernel can be used 2078 as production kernel and capture kernel. Above option should have 2079 gone away after relocatable bzImage support is introduced. But it 2080 is present because there are users out there who continue to use 2081 vmlinux for dump capture. This option should go away down the 2082 line. 2083 2084 Don't change this unless you know what you are doing. 2085 2086config RELOCATABLE 2087 bool "Build a relocatable kernel" 2088 default y 2089 ---help--- 2090 This builds a kernel image that retains relocation information 2091 so it can be loaded someplace besides the default 1MB. 2092 The relocations tend to make the kernel binary about 10% larger, 2093 but are discarded at runtime. 2094 2095 One use is for the kexec on panic case where the recovery kernel 2096 must live at a different physical address than the primary 2097 kernel. 2098 2099 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2100 it has been loaded at and the compile time physical address 2101 (CONFIG_PHYSICAL_START) is used as the minimum location. 2102 2103config RANDOMIZE_BASE 2104 bool "Randomize the address of the kernel image (KASLR)" 2105 depends on RELOCATABLE 2106 default y 2107 ---help--- 2108 In support of Kernel Address Space Layout Randomization (KASLR), 2109 this randomizes the physical address at which the kernel image 2110 is decompressed and the virtual address where the kernel 2111 image is mapped, as a security feature that deters exploit 2112 attempts relying on knowledge of the location of kernel 2113 code internals. 2114 2115 On 64-bit, the kernel physical and virtual addresses are 2116 randomized separately. The physical address will be anywhere 2117 between 16MB and the top of physical memory (up to 64TB). The 2118 virtual address will be randomized from 16MB up to 1GB (9 bits 2119 of entropy). Note that this also reduces the memory space 2120 available to kernel modules from 1.5GB to 1GB. 2121 2122 On 32-bit, the kernel physical and virtual addresses are 2123 randomized together. They will be randomized from 16MB up to 2124 512MB (8 bits of entropy). 2125 2126 Entropy is generated using the RDRAND instruction if it is 2127 supported. If RDTSC is supported, its value is mixed into 2128 the entropy pool as well. If neither RDRAND nor RDTSC are 2129 supported, then entropy is read from the i8254 timer. The 2130 usable entropy is limited by the kernel being built using 2131 2GB addressing, and that PHYSICAL_ALIGN must be at a 2132 minimum of 2MB. As a result, only 10 bits of entropy are 2133 theoretically possible, but the implementations are further 2134 limited due to memory layouts. 2135 2136 If unsure, say Y. 2137 2138# Relocation on x86 needs some additional build support 2139config X86_NEED_RELOCS 2140 def_bool y 2141 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2142 2143config PHYSICAL_ALIGN 2144 hex "Alignment value to which kernel should be aligned" 2145 default "0x200000" 2146 range 0x2000 0x1000000 if X86_32 2147 range 0x200000 0x1000000 if X86_64 2148 ---help--- 2149 This value puts the alignment restrictions on physical address 2150 where kernel is loaded and run from. Kernel is compiled for an 2151 address which meets above alignment restriction. 2152 2153 If bootloader loads the kernel at a non-aligned address and 2154 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2155 address aligned to above value and run from there. 2156 2157 If bootloader loads the kernel at a non-aligned address and 2158 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2159 load address and decompress itself to the address it has been 2160 compiled for and run from there. The address for which kernel is 2161 compiled already meets above alignment restrictions. Hence the 2162 end result is that kernel runs from a physical address meeting 2163 above alignment restrictions. 2164 2165 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2166 this value must be a multiple of 0x200000. 2167 2168 Don't change this unless you know what you are doing. 2169 2170config DYNAMIC_MEMORY_LAYOUT 2171 bool 2172 ---help--- 2173 This option makes base addresses of vmalloc and vmemmap as well as 2174 __PAGE_OFFSET movable during boot. 2175 2176config RANDOMIZE_MEMORY 2177 bool "Randomize the kernel memory sections" 2178 depends on X86_64 2179 depends on RANDOMIZE_BASE 2180 select DYNAMIC_MEMORY_LAYOUT 2181 default RANDOMIZE_BASE 2182 ---help--- 2183 Randomizes the base virtual address of kernel memory sections 2184 (physical memory mapping, vmalloc & vmemmap). This security feature 2185 makes exploits relying on predictable memory locations less reliable. 2186 2187 The order of allocations remains unchanged. Entropy is generated in 2188 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2189 configuration have in average 30,000 different possible virtual 2190 addresses for each memory section. 2191 2192 If unsure, say Y. 2193 2194config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2195 hex "Physical memory mapping padding" if EXPERT 2196 depends on RANDOMIZE_MEMORY 2197 default "0xa" if MEMORY_HOTPLUG 2198 default "0x0" 2199 range 0x1 0x40 if MEMORY_HOTPLUG 2200 range 0x0 0x40 2201 ---help--- 2202 Define the padding in terabytes added to the existing physical 2203 memory size during kernel memory randomization. It is useful 2204 for memory hotplug support but reduces the entropy available for 2205 address randomization. 2206 2207 If unsure, leave at the default value. 2208 2209config HOTPLUG_CPU 2210 bool "Support for hot-pluggable CPUs" 2211 depends on SMP 2212 ---help--- 2213 Say Y here to allow turning CPUs off and on. CPUs can be 2214 controlled through /sys/devices/system/cpu. 2215 ( Note: power management support will enable this option 2216 automatically on SMP systems. ) 2217 Say N if you want to disable CPU hotplug. 2218 2219config BOOTPARAM_HOTPLUG_CPU0 2220 bool "Set default setting of cpu0_hotpluggable" 2221 default n 2222 depends on HOTPLUG_CPU 2223 ---help--- 2224 Set whether default state of cpu0_hotpluggable is on or off. 2225 2226 Say Y here to enable CPU0 hotplug by default. If this switch 2227 is turned on, there is no need to give cpu0_hotplug kernel 2228 parameter and the CPU0 hotplug feature is enabled by default. 2229 2230 Please note: there are two known CPU0 dependencies if you want 2231 to enable the CPU0 hotplug feature either by this switch or by 2232 cpu0_hotplug kernel parameter. 2233 2234 First, resume from hibernate or suspend always starts from CPU0. 2235 So hibernate and suspend are prevented if CPU0 is offline. 2236 2237 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2238 offline if any interrupt can not migrate out of CPU0. There may 2239 be other CPU0 dependencies. 2240 2241 Please make sure the dependencies are under your control before 2242 you enable this feature. 2243 2244 Say N if you don't want to enable CPU0 hotplug feature by default. 2245 You still can enable the CPU0 hotplug feature at boot by kernel 2246 parameter cpu0_hotplug. 2247 2248config DEBUG_HOTPLUG_CPU0 2249 def_bool n 2250 prompt "Debug CPU0 hotplug" 2251 depends on HOTPLUG_CPU 2252 ---help--- 2253 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2254 soon as possible and boots up userspace with CPU0 offlined. User 2255 can online CPU0 back after boot time. 2256 2257 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2258 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2259 compilation or giving cpu0_hotplug kernel parameter at boot. 2260 2261 If unsure, say N. 2262 2263config COMPAT_VDSO 2264 def_bool n 2265 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2266 depends on COMPAT_32 2267 ---help--- 2268 Certain buggy versions of glibc will crash if they are 2269 presented with a 32-bit vDSO that is not mapped at the address 2270 indicated in its segment table. 2271 2272 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2273 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2274 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2275 the only released version with the bug, but OpenSUSE 9 2276 contains a buggy "glibc 2.3.2". 2277 2278 The symptom of the bug is that everything crashes on startup, saying: 2279 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2280 2281 Saying Y here changes the default value of the vdso32 boot 2282 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2283 This works around the glibc bug but hurts performance. 2284 2285 If unsure, say N: if you are compiling your own kernel, you 2286 are unlikely to be using a buggy version of glibc. 2287 2288choice 2289 prompt "vsyscall table for legacy applications" 2290 depends on X86_64 2291 default LEGACY_VSYSCALL_EMULATE 2292 help 2293 Legacy user code that does not know how to find the vDSO expects 2294 to be able to issue three syscalls by calling fixed addresses in 2295 kernel space. Since this location is not randomized with ASLR, 2296 it can be used to assist security vulnerability exploitation. 2297 2298 This setting can be changed at boot time via the kernel command 2299 line parameter vsyscall=[emulate|none]. 2300 2301 On a system with recent enough glibc (2.14 or newer) and no 2302 static binaries, you can say None without a performance penalty 2303 to improve security. 2304 2305 If unsure, select "Emulate". 2306 2307 config LEGACY_VSYSCALL_EMULATE 2308 bool "Emulate" 2309 help 2310 The kernel traps and emulates calls into the fixed 2311 vsyscall address mapping. This makes the mapping 2312 non-executable, but it still contains known contents, 2313 which could be used in certain rare security vulnerability 2314 exploits. This configuration is recommended when userspace 2315 still uses the vsyscall area. 2316 2317 config LEGACY_VSYSCALL_NONE 2318 bool "None" 2319 help 2320 There will be no vsyscall mapping at all. This will 2321 eliminate any risk of ASLR bypass due to the vsyscall 2322 fixed address mapping. Attempts to use the vsyscalls 2323 will be reported to dmesg, so that either old or 2324 malicious userspace programs can be identified. 2325 2326endchoice 2327 2328config CMDLINE_BOOL 2329 bool "Built-in kernel command line" 2330 ---help--- 2331 Allow for specifying boot arguments to the kernel at 2332 build time. On some systems (e.g. embedded ones), it is 2333 necessary or convenient to provide some or all of the 2334 kernel boot arguments with the kernel itself (that is, 2335 to not rely on the boot loader to provide them.) 2336 2337 To compile command line arguments into the kernel, 2338 set this option to 'Y', then fill in the 2339 boot arguments in CONFIG_CMDLINE. 2340 2341 Systems with fully functional boot loaders (i.e. non-embedded) 2342 should leave this option set to 'N'. 2343 2344config CMDLINE 2345 string "Built-in kernel command string" 2346 depends on CMDLINE_BOOL 2347 default "" 2348 ---help--- 2349 Enter arguments here that should be compiled into the kernel 2350 image and used at boot time. If the boot loader provides a 2351 command line at boot time, it is appended to this string to 2352 form the full kernel command line, when the system boots. 2353 2354 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2355 change this behavior. 2356 2357 In most cases, the command line (whether built-in or provided 2358 by the boot loader) should specify the device for the root 2359 file system. 2360 2361config CMDLINE_OVERRIDE 2362 bool "Built-in command line overrides boot loader arguments" 2363 depends on CMDLINE_BOOL 2364 ---help--- 2365 Set this option to 'Y' to have the kernel ignore the boot loader 2366 command line, and use ONLY the built-in command line. 2367 2368 This is used to work around broken boot loaders. This should 2369 be set to 'N' under normal conditions. 2370 2371config MODIFY_LDT_SYSCALL 2372 bool "Enable the LDT (local descriptor table)" if EXPERT 2373 default y 2374 ---help--- 2375 Linux can allow user programs to install a per-process x86 2376 Local Descriptor Table (LDT) using the modify_ldt(2) system 2377 call. This is required to run 16-bit or segmented code such as 2378 DOSEMU or some Wine programs. It is also used by some very old 2379 threading libraries. 2380 2381 Enabling this feature adds a small amount of overhead to 2382 context switches and increases the low-level kernel attack 2383 surface. Disabling it removes the modify_ldt(2) system call. 2384 2385 Saying 'N' here may make sense for embedded or server kernels. 2386 2387source "kernel/livepatch/Kconfig" 2388 2389endmenu 2390 2391config ARCH_HAS_ADD_PAGES 2392 def_bool y 2393 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2394 2395config ARCH_ENABLE_MEMORY_HOTPLUG 2396 def_bool y 2397 depends on X86_64 || (X86_32 && HIGHMEM) 2398 2399config ARCH_ENABLE_MEMORY_HOTREMOVE 2400 def_bool y 2401 depends on MEMORY_HOTPLUG 2402 2403config USE_PERCPU_NUMA_NODE_ID 2404 def_bool y 2405 depends on NUMA 2406 2407config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2408 def_bool y 2409 depends on X86_64 || X86_PAE 2410 2411config ARCH_ENABLE_HUGEPAGE_MIGRATION 2412 def_bool y 2413 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2414 2415config ARCH_ENABLE_THP_MIGRATION 2416 def_bool y 2417 depends on X86_64 && TRANSPARENT_HUGEPAGE 2418 2419menu "Power management and ACPI options" 2420 2421config ARCH_HIBERNATION_HEADER 2422 def_bool y 2423 depends on X86_64 && HIBERNATION 2424 2425source "kernel/power/Kconfig" 2426 2427source "drivers/acpi/Kconfig" 2428 2429source "drivers/sfi/Kconfig" 2430 2431config X86_APM_BOOT 2432 def_bool y 2433 depends on APM 2434 2435menuconfig APM 2436 tristate "APM (Advanced Power Management) BIOS support" 2437 depends on X86_32 && PM_SLEEP 2438 ---help--- 2439 APM is a BIOS specification for saving power using several different 2440 techniques. This is mostly useful for battery powered laptops with 2441 APM compliant BIOSes. If you say Y here, the system time will be 2442 reset after a RESUME operation, the /proc/apm device will provide 2443 battery status information, and user-space programs will receive 2444 notification of APM "events" (e.g. battery status change). 2445 2446 If you select "Y" here, you can disable actual use of the APM 2447 BIOS by passing the "apm=off" option to the kernel at boot time. 2448 2449 Note that the APM support is almost completely disabled for 2450 machines with more than one CPU. 2451 2452 In order to use APM, you will need supporting software. For location 2453 and more information, read <file:Documentation/power/apm-acpi.txt> 2454 and the Battery Powered Linux mini-HOWTO, available from 2455 <http://www.tldp.org/docs.html#howto>. 2456 2457 This driver does not spin down disk drives (see the hdparm(8) 2458 manpage ("man 8 hdparm") for that), and it doesn't turn off 2459 VESA-compliant "green" monitors. 2460 2461 This driver does not support the TI 4000M TravelMate and the ACER 2462 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2463 desktop machines also don't have compliant BIOSes, and this driver 2464 may cause those machines to panic during the boot phase. 2465 2466 Generally, if you don't have a battery in your machine, there isn't 2467 much point in using this driver and you should say N. If you get 2468 random kernel OOPSes or reboots that don't seem to be related to 2469 anything, try disabling/enabling this option (or disabling/enabling 2470 APM in your BIOS). 2471 2472 Some other things you should try when experiencing seemingly random, 2473 "weird" problems: 2474 2475 1) make sure that you have enough swap space and that it is 2476 enabled. 2477 2) pass the "no-hlt" option to the kernel 2478 3) switch on floating point emulation in the kernel and pass 2479 the "no387" option to the kernel 2480 4) pass the "floppy=nodma" option to the kernel 2481 5) pass the "mem=4M" option to the kernel (thereby disabling 2482 all but the first 4 MB of RAM) 2483 6) make sure that the CPU is not over clocked. 2484 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2485 8) disable the cache from your BIOS settings 2486 9) install a fan for the video card or exchange video RAM 2487 10) install a better fan for the CPU 2488 11) exchange RAM chips 2489 12) exchange the motherboard. 2490 2491 To compile this driver as a module, choose M here: the 2492 module will be called apm. 2493 2494if APM 2495 2496config APM_IGNORE_USER_SUSPEND 2497 bool "Ignore USER SUSPEND" 2498 ---help--- 2499 This option will ignore USER SUSPEND requests. On machines with a 2500 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2501 series notebooks, it is necessary to say Y because of a BIOS bug. 2502 2503config APM_DO_ENABLE 2504 bool "Enable PM at boot time" 2505 ---help--- 2506 Enable APM features at boot time. From page 36 of the APM BIOS 2507 specification: "When disabled, the APM BIOS does not automatically 2508 power manage devices, enter the Standby State, enter the Suspend 2509 State, or take power saving steps in response to CPU Idle calls." 2510 This driver will make CPU Idle calls when Linux is idle (unless this 2511 feature is turned off -- see "Do CPU IDLE calls", below). This 2512 should always save battery power, but more complicated APM features 2513 will be dependent on your BIOS implementation. You may need to turn 2514 this option off if your computer hangs at boot time when using APM 2515 support, or if it beeps continuously instead of suspending. Turn 2516 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2517 T400CDT. This is off by default since most machines do fine without 2518 this feature. 2519 2520config APM_CPU_IDLE 2521 depends on CPU_IDLE 2522 bool "Make CPU Idle calls when idle" 2523 ---help--- 2524 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2525 On some machines, this can activate improved power savings, such as 2526 a slowed CPU clock rate, when the machine is idle. These idle calls 2527 are made after the idle loop has run for some length of time (e.g., 2528 333 mS). On some machines, this will cause a hang at boot time or 2529 whenever the CPU becomes idle. (On machines with more than one CPU, 2530 this option does nothing.) 2531 2532config APM_DISPLAY_BLANK 2533 bool "Enable console blanking using APM" 2534 ---help--- 2535 Enable console blanking using the APM. Some laptops can use this to 2536 turn off the LCD backlight when the screen blanker of the Linux 2537 virtual console blanks the screen. Note that this is only used by 2538 the virtual console screen blanker, and won't turn off the backlight 2539 when using the X Window system. This also doesn't have anything to 2540 do with your VESA-compliant power-saving monitor. Further, this 2541 option doesn't work for all laptops -- it might not turn off your 2542 backlight at all, or it might print a lot of errors to the console, 2543 especially if you are using gpm. 2544 2545config APM_ALLOW_INTS 2546 bool "Allow interrupts during APM BIOS calls" 2547 ---help--- 2548 Normally we disable external interrupts while we are making calls to 2549 the APM BIOS as a measure to lessen the effects of a badly behaving 2550 BIOS implementation. The BIOS should reenable interrupts if it 2551 needs to. Unfortunately, some BIOSes do not -- especially those in 2552 many of the newer IBM Thinkpads. If you experience hangs when you 2553 suspend, try setting this to Y. Otherwise, say N. 2554 2555endif # APM 2556 2557source "drivers/cpufreq/Kconfig" 2558 2559source "drivers/cpuidle/Kconfig" 2560 2561source "drivers/idle/Kconfig" 2562 2563endmenu 2564 2565 2566menu "Bus options (PCI etc.)" 2567 2568config PCI 2569 bool "PCI support" 2570 default y 2571 ---help--- 2572 Find out whether you have a PCI motherboard. PCI is the name of a 2573 bus system, i.e. the way the CPU talks to the other stuff inside 2574 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or 2575 VESA. If you have PCI, say Y, otherwise N. 2576 2577choice 2578 prompt "PCI access mode" 2579 depends on X86_32 && PCI 2580 default PCI_GOANY 2581 ---help--- 2582 On PCI systems, the BIOS can be used to detect the PCI devices and 2583 determine their configuration. However, some old PCI motherboards 2584 have BIOS bugs and may crash if this is done. Also, some embedded 2585 PCI-based systems don't have any BIOS at all. Linux can also try to 2586 detect the PCI hardware directly without using the BIOS. 2587 2588 With this option, you can specify how Linux should detect the 2589 PCI devices. If you choose "BIOS", the BIOS will be used, 2590 if you choose "Direct", the BIOS won't be used, and if you 2591 choose "MMConfig", then PCI Express MMCONFIG will be used. 2592 If you choose "Any", the kernel will try MMCONFIG, then the 2593 direct access method and falls back to the BIOS if that doesn't 2594 work. If unsure, go with the default, which is "Any". 2595 2596config PCI_GOBIOS 2597 bool "BIOS" 2598 2599config PCI_GOMMCONFIG 2600 bool "MMConfig" 2601 2602config PCI_GODIRECT 2603 bool "Direct" 2604 2605config PCI_GOOLPC 2606 bool "OLPC XO-1" 2607 depends on OLPC 2608 2609config PCI_GOANY 2610 bool "Any" 2611 2612endchoice 2613 2614config PCI_BIOS 2615 def_bool y 2616 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2617 2618# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2619config PCI_DIRECT 2620 def_bool y 2621 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2622 2623config PCI_MMCONFIG 2624 bool "Support mmconfig PCI config space access" if X86_64 2625 default y 2626 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2627 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2628 2629config PCI_OLPC 2630 def_bool y 2631 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2632 2633config PCI_XEN 2634 def_bool y 2635 depends on PCI && XEN 2636 select SWIOTLB_XEN 2637 2638config PCI_DOMAINS 2639 def_bool y 2640 depends on PCI 2641 2642config MMCONF_FAM10H 2643 def_bool y 2644 depends on X86_64 && PCI_MMCONFIG && ACPI 2645 2646config PCI_CNB20LE_QUIRK 2647 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2648 depends on PCI 2649 help 2650 Read the PCI windows out of the CNB20LE host bridge. This allows 2651 PCI hotplug to work on systems with the CNB20LE chipset which do 2652 not have ACPI. 2653 2654 There's no public spec for this chipset, and this functionality 2655 is known to be incomplete. 2656 2657 You should say N unless you know you need this. 2658 2659source "drivers/pci/Kconfig" 2660 2661config ISA_BUS 2662 bool "ISA bus support on modern systems" if EXPERT 2663 help 2664 Expose ISA bus device drivers and options available for selection and 2665 configuration. Enable this option if your target machine has an ISA 2666 bus. ISA is an older system, displaced by PCI and newer bus 2667 architectures -- if your target machine is modern, it probably does 2668 not have an ISA bus. 2669 2670 If unsure, say N. 2671 2672# x86_64 have no ISA slots, but can have ISA-style DMA. 2673config ISA_DMA_API 2674 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2675 default y 2676 help 2677 Enables ISA-style DMA support for devices requiring such controllers. 2678 If unsure, say Y. 2679 2680if X86_32 2681 2682config ISA 2683 bool "ISA support" 2684 ---help--- 2685 Find out whether you have ISA slots on your motherboard. ISA is the 2686 name of a bus system, i.e. the way the CPU talks to the other stuff 2687 inside your box. Other bus systems are PCI, EISA, MicroChannel 2688 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2689 newer boards don't support it. If you have ISA, say Y, otherwise N. 2690 2691config EISA 2692 bool "EISA support" 2693 depends on ISA 2694 ---help--- 2695 The Extended Industry Standard Architecture (EISA) bus was 2696 developed as an open alternative to the IBM MicroChannel bus. 2697 2698 The EISA bus provided some of the features of the IBM MicroChannel 2699 bus while maintaining backward compatibility with cards made for 2700 the older ISA bus. The EISA bus saw limited use between 1988 and 2701 1995 when it was made obsolete by the PCI bus. 2702 2703 Say Y here if you are building a kernel for an EISA-based machine. 2704 2705 Otherwise, say N. 2706 2707source "drivers/eisa/Kconfig" 2708 2709config SCx200 2710 tristate "NatSemi SCx200 support" 2711 ---help--- 2712 This provides basic support for National Semiconductor's 2713 (now AMD's) Geode processors. The driver probes for the 2714 PCI-IDs of several on-chip devices, so its a good dependency 2715 for other scx200_* drivers. 2716 2717 If compiled as a module, the driver is named scx200. 2718 2719config SCx200HR_TIMER 2720 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2721 depends on SCx200 2722 default y 2723 ---help--- 2724 This driver provides a clocksource built upon the on-chip 2725 27MHz high-resolution timer. Its also a workaround for 2726 NSC Geode SC-1100's buggy TSC, which loses time when the 2727 processor goes idle (as is done by the scheduler). The 2728 other workaround is idle=poll boot option. 2729 2730config OLPC 2731 bool "One Laptop Per Child support" 2732 depends on !X86_PAE 2733 select GPIOLIB 2734 select OF 2735 select OF_PROMTREE 2736 select IRQ_DOMAIN 2737 ---help--- 2738 Add support for detecting the unique features of the OLPC 2739 XO hardware. 2740 2741config OLPC_XO1_PM 2742 bool "OLPC XO-1 Power Management" 2743 depends on OLPC && MFD_CS5535 && PM_SLEEP 2744 select MFD_CORE 2745 ---help--- 2746 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2747 2748config OLPC_XO1_RTC 2749 bool "OLPC XO-1 Real Time Clock" 2750 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2751 ---help--- 2752 Add support for the XO-1 real time clock, which can be used as a 2753 programmable wakeup source. 2754 2755config OLPC_XO1_SCI 2756 bool "OLPC XO-1 SCI extras" 2757 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2758 depends on INPUT=y 2759 select POWER_SUPPLY 2760 ---help--- 2761 Add support for SCI-based features of the OLPC XO-1 laptop: 2762 - EC-driven system wakeups 2763 - Power button 2764 - Ebook switch 2765 - Lid switch 2766 - AC adapter status updates 2767 - Battery status updates 2768 2769config OLPC_XO15_SCI 2770 bool "OLPC XO-1.5 SCI extras" 2771 depends on OLPC && ACPI 2772 select POWER_SUPPLY 2773 ---help--- 2774 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2775 - EC-driven system wakeups 2776 - AC adapter status updates 2777 - Battery status updates 2778 2779config ALIX 2780 bool "PCEngines ALIX System Support (LED setup)" 2781 select GPIOLIB 2782 ---help--- 2783 This option enables system support for the PCEngines ALIX. 2784 At present this just sets up LEDs for GPIO control on 2785 ALIX2/3/6 boards. However, other system specific setup should 2786 get added here. 2787 2788 Note: You must still enable the drivers for GPIO and LED support 2789 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2790 2791 Note: You have to set alix.force=1 for boards with Award BIOS. 2792 2793config NET5501 2794 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2795 select GPIOLIB 2796 ---help--- 2797 This option enables system support for the Soekris Engineering net5501. 2798 2799config GEOS 2800 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2801 select GPIOLIB 2802 depends on DMI 2803 ---help--- 2804 This option enables system support for the Traverse Technologies GEOS. 2805 2806config TS5500 2807 bool "Technologic Systems TS-5500 platform support" 2808 depends on MELAN 2809 select CHECK_SIGNATURE 2810 select NEW_LEDS 2811 select LEDS_CLASS 2812 ---help--- 2813 This option enables system support for the Technologic Systems TS-5500. 2814 2815endif # X86_32 2816 2817config AMD_NB 2818 def_bool y 2819 depends on CPU_SUP_AMD && PCI 2820 2821source "drivers/pcmcia/Kconfig" 2822 2823config RAPIDIO 2824 tristate "RapidIO support" 2825 depends on PCI 2826 default n 2827 help 2828 If enabled this option will include drivers and the core 2829 infrastructure code to support RapidIO interconnect devices. 2830 2831source "drivers/rapidio/Kconfig" 2832 2833config X86_SYSFB 2834 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2835 help 2836 Firmwares often provide initial graphics framebuffers so the BIOS, 2837 bootloader or kernel can show basic video-output during boot for 2838 user-guidance and debugging. Historically, x86 used the VESA BIOS 2839 Extensions and EFI-framebuffers for this, which are mostly limited 2840 to x86. 2841 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2842 framebuffers so the new generic system-framebuffer drivers can be 2843 used on x86. If the framebuffer is not compatible with the generic 2844 modes, it is adverticed as fallback platform framebuffer so legacy 2845 drivers like efifb, vesafb and uvesafb can pick it up. 2846 If this option is not selected, all system framebuffers are always 2847 marked as fallback platform framebuffers as usual. 2848 2849 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2850 not be able to pick up generic system framebuffers if this option 2851 is selected. You are highly encouraged to enable simplefb as 2852 replacement if you select this option. simplefb can correctly deal 2853 with generic system framebuffers. But you should still keep vesafb 2854 and others enabled as fallback if a system framebuffer is 2855 incompatible with simplefb. 2856 2857 If unsure, say Y. 2858 2859endmenu 2860 2861 2862menu "Executable file formats / Emulations" 2863 2864source "fs/Kconfig.binfmt" 2865 2866config IA32_EMULATION 2867 bool "IA32 Emulation" 2868 depends on X86_64 2869 select ARCH_WANT_OLD_COMPAT_IPC 2870 select BINFMT_ELF 2871 select COMPAT_BINFMT_ELF 2872 select COMPAT_OLD_SIGACTION 2873 ---help--- 2874 Include code to run legacy 32-bit programs under a 2875 64-bit kernel. You should likely turn this on, unless you're 2876 100% sure that you don't have any 32-bit programs left. 2877 2878config IA32_AOUT 2879 tristate "IA32 a.out support" 2880 depends on IA32_EMULATION 2881 ---help--- 2882 Support old a.out binaries in the 32bit emulation. 2883 2884config X86_X32 2885 bool "x32 ABI for 64-bit mode" 2886 depends on X86_64 2887 ---help--- 2888 Include code to run binaries for the x32 native 32-bit ABI 2889 for 64-bit processors. An x32 process gets access to the 2890 full 64-bit register file and wide data path while leaving 2891 pointers at 32 bits for smaller memory footprint. 2892 2893 You will need a recent binutils (2.22 or later) with 2894 elf32_x86_64 support enabled to compile a kernel with this 2895 option set. 2896 2897config COMPAT_32 2898 def_bool y 2899 depends on IA32_EMULATION || X86_32 2900 select HAVE_UID16 2901 select OLD_SIGSUSPEND3 2902 2903config COMPAT 2904 def_bool y 2905 depends on IA32_EMULATION || X86_X32 2906 2907if COMPAT 2908config COMPAT_FOR_U64_ALIGNMENT 2909 def_bool y 2910 2911config SYSVIPC_COMPAT 2912 def_bool y 2913 depends on SYSVIPC 2914endif 2915 2916endmenu 2917 2918 2919config HAVE_ATOMIC_IOMAP 2920 def_bool y 2921 depends on X86_32 2922 2923config X86_DEV_DMA_OPS 2924 bool 2925 depends on X86_64 || STA2X11 2926 2927config X86_DMA_REMAP 2928 bool 2929 depends on STA2X11 2930 2931config HAVE_GENERIC_GUP 2932 def_bool y 2933 2934source "net/Kconfig" 2935 2936source "drivers/Kconfig" 2937 2938source "drivers/firmware/Kconfig" 2939 2940source "fs/Kconfig" 2941 2942source "arch/x86/Kconfig.debug" 2943 2944source "security/Kconfig" 2945 2946source "crypto/Kconfig" 2947 2948source "arch/x86/kvm/Kconfig" 2949 2950source "lib/Kconfig" 2951