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_PTE_SPECIAL 64 select ARCH_HAS_REFCOUNT 65 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 66 select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE 67 select ARCH_HAS_SET_MEMORY 68 select ARCH_HAS_SG_CHAIN 69 select ARCH_HAS_STRICT_KERNEL_RWX 70 select ARCH_HAS_STRICT_MODULE_RWX 71 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 72 select ARCH_HAS_UBSAN_SANITIZE_ALL 73 select ARCH_HAS_ZONE_DEVICE if X86_64 74 select ARCH_HAVE_NMI_SAFE_CMPXCHG 75 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 76 select ARCH_MIGHT_HAVE_PC_PARPORT 77 select ARCH_MIGHT_HAVE_PC_SERIO 78 select ARCH_SUPPORTS_ATOMIC_RMW 79 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 80 select ARCH_USE_BUILTIN_BSWAP 81 select ARCH_USE_QUEUED_RWLOCKS 82 select ARCH_USE_QUEUED_SPINLOCKS 83 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 84 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 85 select ARCH_WANTS_THP_SWAP if X86_64 86 select BUILDTIME_EXTABLE_SORT 87 select CLKEVT_I8253 88 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 89 select CLOCKSOURCE_WATCHDOG 90 select DCACHE_WORD_ACCESS 91 select DMA_DIRECT_OPS 92 select EDAC_ATOMIC_SCRUB 93 select EDAC_SUPPORT 94 select GENERIC_CLOCKEVENTS 95 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 96 select GENERIC_CLOCKEVENTS_MIN_ADJUST 97 select GENERIC_CMOS_UPDATE 98 select GENERIC_CPU_AUTOPROBE 99 select GENERIC_CPU_VULNERABILITIES 100 select GENERIC_EARLY_IOREMAP 101 select GENERIC_FIND_FIRST_BIT 102 select GENERIC_IOMAP 103 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 104 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 105 select GENERIC_IRQ_MIGRATION if SMP 106 select GENERIC_IRQ_PROBE 107 select GENERIC_IRQ_RESERVATION_MODE 108 select GENERIC_IRQ_SHOW 109 select GENERIC_PENDING_IRQ if SMP 110 select GENERIC_SMP_IDLE_THREAD 111 select GENERIC_STRNCPY_FROM_USER 112 select GENERIC_STRNLEN_USER 113 select GENERIC_TIME_VSYSCALL 114 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 115 select HAVE_ACPI_APEI if ACPI 116 select HAVE_ACPI_APEI_NMI if ACPI 117 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 118 select HAVE_ARCH_AUDITSYSCALL 119 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 120 select HAVE_ARCH_JUMP_LABEL 121 select HAVE_ARCH_KASAN if X86_64 122 select HAVE_ARCH_KGDB 123 select HAVE_ARCH_MMAP_RND_BITS if MMU 124 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 125 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 126 select HAVE_ARCH_SECCOMP_FILTER 127 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 128 select HAVE_ARCH_TRACEHOOK 129 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 130 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 131 select HAVE_ARCH_VMAP_STACK if X86_64 132 select HAVE_ARCH_WITHIN_STACK_FRAMES 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 || UNWINDER_ORC) && STACK_VALIDATION 184 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 185 select HAVE_STACK_VALIDATION if X86_64 186 select HAVE_RSEQ 187 select HAVE_SYSCALL_TRACEPOINTS 188 select HAVE_UNSTABLE_SCHED_CLOCK 189 select HAVE_USER_RETURN_NOTIFIER 190 select HOTPLUG_SMT if SMP 191 select IRQ_FORCED_THREADING 192 select NEED_SG_DMA_LENGTH 193 select PCI_LOCKLESS_CONFIG 194 select PERF_EVENTS 195 select RTC_LIB 196 select RTC_MC146818_LIB 197 select SPARSE_IRQ 198 select SRCU 199 select SYSCTL_EXCEPTION_TRACE 200 select THREAD_INFO_IN_TASK 201 select USER_STACKTRACE_SUPPORT 202 select VIRT_TO_BUS 203 select X86_FEATURE_NAMES if PROC_FS 204 205config INSTRUCTION_DECODER 206 def_bool y 207 depends on KPROBES || PERF_EVENTS || UPROBES 208 209config OUTPUT_FORMAT 210 string 211 default "elf32-i386" if X86_32 212 default "elf64-x86-64" if X86_64 213 214config ARCH_DEFCONFIG 215 string 216 default "arch/x86/configs/i386_defconfig" if X86_32 217 default "arch/x86/configs/x86_64_defconfig" if X86_64 218 219config LOCKDEP_SUPPORT 220 def_bool y 221 222config STACKTRACE_SUPPORT 223 def_bool y 224 225config MMU 226 def_bool y 227 228config ARCH_MMAP_RND_BITS_MIN 229 default 28 if 64BIT 230 default 8 231 232config ARCH_MMAP_RND_BITS_MAX 233 default 32 if 64BIT 234 default 16 235 236config ARCH_MMAP_RND_COMPAT_BITS_MIN 237 default 8 238 239config ARCH_MMAP_RND_COMPAT_BITS_MAX 240 default 16 241 242config SBUS 243 bool 244 245config GENERIC_ISA_DMA 246 def_bool y 247 depends on ISA_DMA_API 248 249config GENERIC_BUG 250 def_bool y 251 depends on BUG 252 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 253 254config GENERIC_BUG_RELATIVE_POINTERS 255 bool 256 257config GENERIC_HWEIGHT 258 def_bool y 259 260config ARCH_MAY_HAVE_PC_FDC 261 def_bool y 262 depends on ISA_DMA_API 263 264config RWSEM_XCHGADD_ALGORITHM 265 def_bool y 266 267config GENERIC_CALIBRATE_DELAY 268 def_bool y 269 270config ARCH_HAS_CPU_RELAX 271 def_bool y 272 273config ARCH_HAS_CACHE_LINE_SIZE 274 def_bool y 275 276config ARCH_HAS_FILTER_PGPROT 277 def_bool y 278 279config HAVE_SETUP_PER_CPU_AREA 280 def_bool y 281 282config NEED_PER_CPU_EMBED_FIRST_CHUNK 283 def_bool y 284 285config NEED_PER_CPU_PAGE_FIRST_CHUNK 286 def_bool y 287 288config ARCH_HIBERNATION_POSSIBLE 289 def_bool y 290 291config ARCH_SUSPEND_POSSIBLE 292 def_bool y 293 294config ARCH_WANT_HUGE_PMD_SHARE 295 def_bool y 296 297config ARCH_WANT_GENERAL_HUGETLB 298 def_bool y 299 300config ZONE_DMA32 301 def_bool y if X86_64 302 303config AUDIT_ARCH 304 def_bool y if X86_64 305 306config ARCH_SUPPORTS_OPTIMIZED_INLINING 307 def_bool y 308 309config ARCH_SUPPORTS_DEBUG_PAGEALLOC 310 def_bool y 311 312config KASAN_SHADOW_OFFSET 313 hex 314 depends on KASAN 315 default 0xdffffc0000000000 316 317config HAVE_INTEL_TXT 318 def_bool y 319 depends on INTEL_IOMMU && ACPI 320 321config X86_32_SMP 322 def_bool y 323 depends on X86_32 && SMP 324 325config X86_64_SMP 326 def_bool y 327 depends on X86_64 && SMP 328 329config X86_32_LAZY_GS 330 def_bool y 331 depends on X86_32 && !STACKPROTECTOR 332 333config ARCH_SUPPORTS_UPROBES 334 def_bool y 335 336config FIX_EARLYCON_MEM 337 def_bool y 338 339config DYNAMIC_PHYSICAL_MASK 340 bool 341 342config PGTABLE_LEVELS 343 int 344 default 5 if X86_5LEVEL 345 default 4 if X86_64 346 default 3 if X86_PAE 347 default 2 348 349source "init/Kconfig" 350 351config CC_HAS_SANE_STACKPROTECTOR 352 bool 353 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 354 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 355 help 356 We have to make sure stack protector is unconditionally disabled if 357 the compiler produces broken code. 358 359source "kernel/Kconfig.freezer" 360 361menu "Processor type and features" 362 363config ZONE_DMA 364 bool "DMA memory allocation support" if EXPERT 365 default y 366 help 367 DMA memory allocation support allows devices with less than 32-bit 368 addressing to allocate within the first 16MB of address space. 369 Disable if no such devices will be used. 370 371 If unsure, say Y. 372 373config SMP 374 bool "Symmetric multi-processing support" 375 ---help--- 376 This enables support for systems with more than one CPU. If you have 377 a system with only one CPU, say N. If you have a system with more 378 than one CPU, say Y. 379 380 If you say N here, the kernel will run on uni- and multiprocessor 381 machines, but will use only one CPU of a multiprocessor machine. If 382 you say Y here, the kernel will run on many, but not all, 383 uniprocessor machines. On a uniprocessor machine, the kernel 384 will run faster if you say N here. 385 386 Note that if you say Y here and choose architecture "586" or 387 "Pentium" under "Processor family", the kernel will not work on 486 388 architectures. Similarly, multiprocessor kernels for the "PPro" 389 architecture may not work on all Pentium based boards. 390 391 People using multiprocessor machines who say Y here should also say 392 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 393 Management" code will be disabled if you say Y here. 394 395 See also <file:Documentation/x86/i386/IO-APIC.txt>, 396 <file:Documentation/lockup-watchdogs.txt> and the SMP-HOWTO available at 397 <http://www.tldp.org/docs.html#howto>. 398 399 If you don't know what to do here, say N. 400 401config X86_FEATURE_NAMES 402 bool "Processor feature human-readable names" if EMBEDDED 403 default y 404 ---help--- 405 This option compiles in a table of x86 feature bits and corresponding 406 names. This is required to support /proc/cpuinfo and a few kernel 407 messages. You can disable this to save space, at the expense of 408 making those few kernel messages show numeric feature bits instead. 409 410 If in doubt, say Y. 411 412config X86_X2APIC 413 bool "Support x2apic" 414 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 415 ---help--- 416 This enables x2apic support on CPUs that have this feature. 417 418 This allows 32-bit apic IDs (so it can support very large systems), 419 and accesses the local apic via MSRs not via mmio. 420 421 If you don't know what to do here, say N. 422 423config X86_MPPARSE 424 bool "Enable MPS table" if ACPI || SFI 425 default y 426 depends on X86_LOCAL_APIC 427 ---help--- 428 For old smp systems that do not have proper acpi support. Newer systems 429 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 430 431config GOLDFISH 432 def_bool y 433 depends on X86_GOLDFISH 434 435config RETPOLINE 436 bool "Avoid speculative indirect branches in kernel" 437 default y 438 select STACK_VALIDATION if HAVE_STACK_VALIDATION 439 help 440 Compile kernel with the retpoline compiler options to guard against 441 kernel-to-user data leaks by avoiding speculative indirect 442 branches. Requires a compiler with -mindirect-branch=thunk-extern 443 support for full protection. The kernel may run slower. 444 445 Without compiler support, at least indirect branches in assembler 446 code are eliminated. Since this includes the syscall entry path, 447 it is not entirely pointless. 448 449config INTEL_RDT 450 bool "Intel Resource Director Technology support" 451 default n 452 depends on X86 && CPU_SUP_INTEL 453 select KERNFS 454 help 455 Select to enable resource allocation and monitoring which are 456 sub-features of Intel Resource Director Technology(RDT). More 457 information about RDT can be found in the Intel x86 458 Architecture Software Developer Manual. 459 460 Say N if unsure. 461 462if X86_32 463config X86_BIGSMP 464 bool "Support for big SMP systems with more than 8 CPUs" 465 depends on SMP 466 ---help--- 467 This option is needed for the systems that have more than 8 CPUs 468 469config X86_EXTENDED_PLATFORM 470 bool "Support for extended (non-PC) x86 platforms" 471 default y 472 ---help--- 473 If you disable this option then the kernel will only support 474 standard PC platforms. (which covers the vast majority of 475 systems out there.) 476 477 If you enable this option then you'll be able to select support 478 for the following (non-PC) 32 bit x86 platforms: 479 Goldfish (Android emulator) 480 AMD Elan 481 RDC R-321x SoC 482 SGI 320/540 (Visual Workstation) 483 STA2X11-based (e.g. Northville) 484 Moorestown MID devices 485 486 If you have one of these systems, or if you want to build a 487 generic distribution kernel, say Y here - otherwise say N. 488endif 489 490if X86_64 491config X86_EXTENDED_PLATFORM 492 bool "Support for extended (non-PC) x86 platforms" 493 default y 494 ---help--- 495 If you disable this option then the kernel will only support 496 standard PC platforms. (which covers the vast majority of 497 systems out there.) 498 499 If you enable this option then you'll be able to select support 500 for the following (non-PC) 64 bit x86 platforms: 501 Numascale NumaChip 502 ScaleMP vSMP 503 SGI Ultraviolet 504 505 If you have one of these systems, or if you want to build a 506 generic distribution kernel, say Y here - otherwise say N. 507endif 508# This is an alphabetically sorted list of 64 bit extended platforms 509# Please maintain the alphabetic order if and when there are additions 510config X86_NUMACHIP 511 bool "Numascale NumaChip" 512 depends on X86_64 513 depends on X86_EXTENDED_PLATFORM 514 depends on NUMA 515 depends on SMP 516 depends on X86_X2APIC 517 depends on PCI_MMCONFIG 518 ---help--- 519 Adds support for Numascale NumaChip large-SMP systems. Needed to 520 enable more than ~168 cores. 521 If you don't have one of these, you should say N here. 522 523config X86_VSMP 524 bool "ScaleMP vSMP" 525 select HYPERVISOR_GUEST 526 select PARAVIRT 527 depends on X86_64 && PCI 528 depends on X86_EXTENDED_PLATFORM 529 depends on SMP 530 ---help--- 531 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 532 supposed to run on these EM64T-based machines. Only choose this option 533 if you have one of these machines. 534 535config X86_UV 536 bool "SGI Ultraviolet" 537 depends on X86_64 538 depends on X86_EXTENDED_PLATFORM 539 depends on NUMA 540 depends on EFI 541 depends on X86_X2APIC 542 depends on PCI 543 ---help--- 544 This option is needed in order to support SGI Ultraviolet systems. 545 If you don't have one of these, you should say N here. 546 547# Following is an alphabetically sorted list of 32 bit extended platforms 548# Please maintain the alphabetic order if and when there are additions 549 550config X86_GOLDFISH 551 bool "Goldfish (Virtual Platform)" 552 depends on X86_EXTENDED_PLATFORM 553 ---help--- 554 Enable support for the Goldfish virtual platform used primarily 555 for Android development. Unless you are building for the Android 556 Goldfish emulator say N here. 557 558config X86_INTEL_CE 559 bool "CE4100 TV platform" 560 depends on PCI 561 depends on PCI_GODIRECT 562 depends on X86_IO_APIC 563 depends on X86_32 564 depends on X86_EXTENDED_PLATFORM 565 select X86_REBOOTFIXUPS 566 select OF 567 select OF_EARLY_FLATTREE 568 ---help--- 569 Select for the Intel CE media processor (CE4100) SOC. 570 This option compiles in support for the CE4100 SOC for settop 571 boxes and media devices. 572 573config X86_INTEL_MID 574 bool "Intel MID platform support" 575 depends on X86_EXTENDED_PLATFORM 576 depends on X86_PLATFORM_DEVICES 577 depends on PCI 578 depends on X86_64 || (PCI_GOANY && X86_32) 579 depends on X86_IO_APIC 580 select SFI 581 select I2C 582 select DW_APB_TIMER 583 select APB_TIMER 584 select INTEL_SCU_IPC 585 select MFD_INTEL_MSIC 586 ---help--- 587 Select to build a kernel capable of supporting Intel MID (Mobile 588 Internet Device) platform systems which do not have the PCI legacy 589 interfaces. If you are building for a PC class system say N here. 590 591 Intel MID platforms are based on an Intel processor and chipset which 592 consume less power than most of the x86 derivatives. 593 594config X86_INTEL_QUARK 595 bool "Intel Quark platform support" 596 depends on X86_32 597 depends on X86_EXTENDED_PLATFORM 598 depends on X86_PLATFORM_DEVICES 599 depends on X86_TSC 600 depends on PCI 601 depends on PCI_GOANY 602 depends on X86_IO_APIC 603 select IOSF_MBI 604 select INTEL_IMR 605 select COMMON_CLK 606 ---help--- 607 Select to include support for Quark X1000 SoC. 608 Say Y here if you have a Quark based system such as the Arduino 609 compatible Intel Galileo. 610 611config X86_INTEL_LPSS 612 bool "Intel Low Power Subsystem Support" 613 depends on X86 && ACPI 614 select COMMON_CLK 615 select PINCTRL 616 select IOSF_MBI 617 ---help--- 618 Select to build support for Intel Low Power Subsystem such as 619 found on Intel Lynxpoint PCH. Selecting this option enables 620 things like clock tree (common clock framework) and pincontrol 621 which are needed by the LPSS peripheral drivers. 622 623config X86_AMD_PLATFORM_DEVICE 624 bool "AMD ACPI2Platform devices support" 625 depends on ACPI 626 select COMMON_CLK 627 select PINCTRL 628 ---help--- 629 Select to interpret AMD specific ACPI device to platform device 630 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 631 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 632 implemented under PINCTRL subsystem. 633 634config IOSF_MBI 635 tristate "Intel SoC IOSF Sideband support for SoC platforms" 636 depends on PCI 637 ---help--- 638 This option enables sideband register access support for Intel SoC 639 platforms. On these platforms the IOSF sideband is used in lieu of 640 MSR's for some register accesses, mostly but not limited to thermal 641 and power. Drivers may query the availability of this device to 642 determine if they need the sideband in order to work on these 643 platforms. The sideband is available on the following SoC products. 644 This list is not meant to be exclusive. 645 - BayTrail 646 - Braswell 647 - Quark 648 649 You should say Y if you are running a kernel on one of these SoC's. 650 651config IOSF_MBI_DEBUG 652 bool "Enable IOSF sideband access through debugfs" 653 depends on IOSF_MBI && DEBUG_FS 654 ---help--- 655 Select this option to expose the IOSF sideband access registers (MCR, 656 MDR, MCRX) through debugfs to write and read register information from 657 different units on the SoC. This is most useful for obtaining device 658 state information for debug and analysis. As this is a general access 659 mechanism, users of this option would have specific knowledge of the 660 device they want to access. 661 662 If you don't require the option or are in doubt, say N. 663 664config X86_RDC321X 665 bool "RDC R-321x SoC" 666 depends on X86_32 667 depends on X86_EXTENDED_PLATFORM 668 select M486 669 select X86_REBOOTFIXUPS 670 ---help--- 671 This option is needed for RDC R-321x system-on-chip, also known 672 as R-8610-(G). 673 If you don't have one of these chips, you should say N here. 674 675config X86_32_NON_STANDARD 676 bool "Support non-standard 32-bit SMP architectures" 677 depends on X86_32 && SMP 678 depends on X86_EXTENDED_PLATFORM 679 ---help--- 680 This option compiles in the bigsmp and STA2X11 default 681 subarchitectures. It is intended for a generic binary 682 kernel. If you select them all, kernel will probe it one by 683 one and will fallback to default. 684 685# Alphabetically sorted list of Non standard 32 bit platforms 686 687config X86_SUPPORTS_MEMORY_FAILURE 688 def_bool y 689 # MCE code calls memory_failure(): 690 depends on X86_MCE 691 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 692 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 693 depends on X86_64 || !SPARSEMEM 694 select ARCH_SUPPORTS_MEMORY_FAILURE 695 696config STA2X11 697 bool "STA2X11 Companion Chip Support" 698 depends on X86_32_NON_STANDARD && PCI 699 select ARCH_HAS_PHYS_TO_DMA 700 select X86_DEV_DMA_OPS 701 select X86_DMA_REMAP 702 select SWIOTLB 703 select MFD_STA2X11 704 select GPIOLIB 705 default n 706 ---help--- 707 This adds support for boards based on the STA2X11 IO-Hub, 708 a.k.a. "ConneXt". The chip is used in place of the standard 709 PC chipset, so all "standard" peripherals are missing. If this 710 option is selected the kernel will still be able to boot on 711 standard PC machines. 712 713config X86_32_IRIS 714 tristate "Eurobraille/Iris poweroff module" 715 depends on X86_32 716 ---help--- 717 The Iris machines from EuroBraille do not have APM or ACPI support 718 to shut themselves down properly. A special I/O sequence is 719 needed to do so, which is what this module does at 720 kernel shutdown. 721 722 This is only for Iris machines from EuroBraille. 723 724 If unused, say N. 725 726config SCHED_OMIT_FRAME_POINTER 727 def_bool y 728 prompt "Single-depth WCHAN output" 729 depends on X86 730 ---help--- 731 Calculate simpler /proc/<PID>/wchan values. If this option 732 is disabled then wchan values will recurse back to the 733 caller function. This provides more accurate wchan values, 734 at the expense of slightly more scheduling overhead. 735 736 If in doubt, say "Y". 737 738menuconfig HYPERVISOR_GUEST 739 bool "Linux guest support" 740 ---help--- 741 Say Y here to enable options for running Linux under various hyper- 742 visors. This option enables basic hypervisor detection and platform 743 setup. 744 745 If you say N, all options in this submenu will be skipped and 746 disabled, and Linux guest support won't be built in. 747 748if HYPERVISOR_GUEST 749 750config PARAVIRT 751 bool "Enable paravirtualization code" 752 ---help--- 753 This changes the kernel so it can modify itself when it is run 754 under a hypervisor, potentially improving performance significantly 755 over full virtualization. However, when run without a hypervisor 756 the kernel is theoretically slower and slightly larger. 757 758config PARAVIRT_DEBUG 759 bool "paravirt-ops debugging" 760 depends on PARAVIRT && DEBUG_KERNEL 761 ---help--- 762 Enable to debug paravirt_ops internals. Specifically, BUG if 763 a paravirt_op is missing when it is called. 764 765config PARAVIRT_SPINLOCKS 766 bool "Paravirtualization layer for spinlocks" 767 depends on PARAVIRT && SMP 768 ---help--- 769 Paravirtualized spinlocks allow a pvops backend to replace the 770 spinlock implementation with something virtualization-friendly 771 (for example, block the virtual CPU rather than spinning). 772 773 It has a minimal impact on native kernels and gives a nice performance 774 benefit on paravirtualized KVM / Xen kernels. 775 776 If you are unsure how to answer this question, answer Y. 777 778config QUEUED_LOCK_STAT 779 bool "Paravirt queued spinlock statistics" 780 depends on PARAVIRT_SPINLOCKS && DEBUG_FS 781 ---help--- 782 Enable the collection of statistical data on the slowpath 783 behavior of paravirtualized queued spinlocks and report 784 them on debugfs. 785 786source "arch/x86/xen/Kconfig" 787 788config KVM_GUEST 789 bool "KVM Guest support (including kvmclock)" 790 depends on PARAVIRT 791 select PARAVIRT_CLOCK 792 default y 793 ---help--- 794 This option enables various optimizations for running under the KVM 795 hypervisor. It includes a paravirtualized clock, so that instead 796 of relying on a PIT (or probably other) emulation by the 797 underlying device model, the host provides the guest with 798 timing infrastructure such as time of day, and system time 799 800config KVM_DEBUG_FS 801 bool "Enable debug information for KVM Guests in debugfs" 802 depends on KVM_GUEST && DEBUG_FS 803 default n 804 ---help--- 805 This option enables collection of various statistics for KVM guest. 806 Statistics are displayed in debugfs filesystem. Enabling this option 807 may incur significant overhead. 808 809config PARAVIRT_TIME_ACCOUNTING 810 bool "Paravirtual steal time accounting" 811 depends on PARAVIRT 812 default n 813 ---help--- 814 Select this option to enable fine granularity task steal time 815 accounting. Time spent executing other tasks in parallel with 816 the current vCPU is discounted from the vCPU power. To account for 817 that, there can be a small performance impact. 818 819 If in doubt, say N here. 820 821config PARAVIRT_CLOCK 822 bool 823 824config JAILHOUSE_GUEST 825 bool "Jailhouse non-root cell support" 826 depends on X86_64 && PCI 827 select X86_PM_TIMER 828 ---help--- 829 This option allows to run Linux as guest in a Jailhouse non-root 830 cell. You can leave this option disabled if you only want to start 831 Jailhouse and run Linux afterwards in the root cell. 832 833endif #HYPERVISOR_GUEST 834 835config NO_BOOTMEM 836 def_bool y 837 838source "arch/x86/Kconfig.cpu" 839 840config HPET_TIMER 841 def_bool X86_64 842 prompt "HPET Timer Support" if X86_32 843 ---help--- 844 Use the IA-PC HPET (High Precision Event Timer) to manage 845 time in preference to the PIT and RTC, if a HPET is 846 present. 847 HPET is the next generation timer replacing legacy 8254s. 848 The HPET provides a stable time base on SMP 849 systems, unlike the TSC, but it is more expensive to access, 850 as it is off-chip. The interface used is documented 851 in the HPET spec, revision 1. 852 853 You can safely choose Y here. However, HPET will only be 854 activated if the platform and the BIOS support this feature. 855 Otherwise the 8254 will be used for timing services. 856 857 Choose N to continue using the legacy 8254 timer. 858 859config HPET_EMULATE_RTC 860 def_bool y 861 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 862 863config APB_TIMER 864 def_bool y if X86_INTEL_MID 865 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 866 select DW_APB_TIMER 867 depends on X86_INTEL_MID && SFI 868 help 869 APB timer is the replacement for 8254, HPET on X86 MID platforms. 870 The APBT provides a stable time base on SMP 871 systems, unlike the TSC, but it is more expensive to access, 872 as it is off-chip. APB timers are always running regardless of CPU 873 C states, they are used as per CPU clockevent device when possible. 874 875# Mark as expert because too many people got it wrong. 876# The code disables itself when not needed. 877config DMI 878 default y 879 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 880 bool "Enable DMI scanning" if EXPERT 881 ---help--- 882 Enabled scanning of DMI to identify machine quirks. Say Y 883 here unless you have verified that your setup is not 884 affected by entries in the DMI blacklist. Required by PNP 885 BIOS code. 886 887config GART_IOMMU 888 bool "Old AMD GART IOMMU support" 889 select IOMMU_HELPER 890 select SWIOTLB 891 depends on X86_64 && PCI && AMD_NB 892 ---help--- 893 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 894 GART based hardware IOMMUs. 895 896 The GART supports full DMA access for devices with 32-bit access 897 limitations, on systems with more than 3 GB. This is usually needed 898 for USB, sound, many IDE/SATA chipsets and some other devices. 899 900 Newer systems typically have a modern AMD IOMMU, supported via 901 the CONFIG_AMD_IOMMU=y config option. 902 903 In normal configurations this driver is only active when needed: 904 there's more than 3 GB of memory and the system contains a 905 32-bit limited device. 906 907 If unsure, say Y. 908 909config CALGARY_IOMMU 910 bool "IBM Calgary IOMMU support" 911 select IOMMU_HELPER 912 select SWIOTLB 913 depends on X86_64 && PCI 914 ---help--- 915 Support for hardware IOMMUs in IBM's xSeries x366 and x460 916 systems. Needed to run systems with more than 3GB of memory 917 properly with 32-bit PCI devices that do not support DAC 918 (Double Address Cycle). Calgary also supports bus level 919 isolation, where all DMAs pass through the IOMMU. This 920 prevents them from going anywhere except their intended 921 destination. This catches hard-to-find kernel bugs and 922 mis-behaving drivers and devices that do not use the DMA-API 923 properly to set up their DMA buffers. The IOMMU can be 924 turned off at boot time with the iommu=off parameter. 925 Normally the kernel will make the right choice by itself. 926 If unsure, say Y. 927 928config CALGARY_IOMMU_ENABLED_BY_DEFAULT 929 def_bool y 930 prompt "Should Calgary be enabled by default?" 931 depends on CALGARY_IOMMU 932 ---help--- 933 Should Calgary be enabled by default? if you choose 'y', Calgary 934 will be used (if it exists). If you choose 'n', Calgary will not be 935 used even if it exists. If you choose 'n' and would like to use 936 Calgary anyway, pass 'iommu=calgary' on the kernel command line. 937 If unsure, say Y. 938 939config MAXSMP 940 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 941 depends on X86_64 && SMP && DEBUG_KERNEL 942 select CPUMASK_OFFSTACK 943 ---help--- 944 Enable maximum number of CPUS and NUMA Nodes for this architecture. 945 If unsure, say N. 946 947# 948# The maximum number of CPUs supported: 949# 950# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 951# and which can be configured interactively in the 952# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 953# 954# The ranges are different on 32-bit and 64-bit kernels, depending on 955# hardware capabilities and scalability features of the kernel. 956# 957# ( If MAXSMP is enabled we just use the highest possible value and disable 958# interactive configuration. ) 959# 960 961config NR_CPUS_RANGE_BEGIN 962 int 963 default NR_CPUS_RANGE_END if MAXSMP 964 default 1 if !SMP 965 default 2 966 967config NR_CPUS_RANGE_END 968 int 969 depends on X86_32 970 default 64 if SMP && X86_BIGSMP 971 default 8 if SMP && !X86_BIGSMP 972 default 1 if !SMP 973 974config NR_CPUS_RANGE_END 975 int 976 depends on X86_64 977 default 8192 if SMP && ( MAXSMP || CPUMASK_OFFSTACK) 978 default 512 if SMP && (!MAXSMP && !CPUMASK_OFFSTACK) 979 default 1 if !SMP 980 981config NR_CPUS_DEFAULT 982 int 983 depends on X86_32 984 default 32 if X86_BIGSMP 985 default 8 if SMP 986 default 1 if !SMP 987 988config NR_CPUS_DEFAULT 989 int 990 depends on X86_64 991 default 8192 if MAXSMP 992 default 64 if SMP 993 default 1 if !SMP 994 995config NR_CPUS 996 int "Maximum number of CPUs" if SMP && !MAXSMP 997 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 998 default NR_CPUS_DEFAULT 999 ---help--- 1000 This allows you to specify the maximum number of CPUs which this 1001 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1002 supported value is 8192, otherwise the maximum value is 512. The 1003 minimum value which makes sense is 2. 1004 1005 This is purely to save memory: each supported CPU adds about 8KB 1006 to the kernel image. 1007 1008config SCHED_SMT 1009 bool "SMT (Hyperthreading) scheduler support" 1010 depends on SMP 1011 ---help--- 1012 SMT scheduler support improves the CPU scheduler's decision making 1013 when dealing with Intel Pentium 4 chips with HyperThreading at a 1014 cost of slightly increased overhead in some places. If unsure say 1015 N here. 1016 1017config SCHED_MC 1018 def_bool y 1019 prompt "Multi-core scheduler support" 1020 depends on SMP 1021 ---help--- 1022 Multi-core scheduler support improves the CPU scheduler's decision 1023 making when dealing with multi-core CPU chips at a cost of slightly 1024 increased overhead in some places. If unsure say N here. 1025 1026config SCHED_MC_PRIO 1027 bool "CPU core priorities scheduler support" 1028 depends on SCHED_MC && CPU_SUP_INTEL 1029 select X86_INTEL_PSTATE 1030 select CPU_FREQ 1031 default y 1032 ---help--- 1033 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1034 core ordering determined at manufacturing time, which allows 1035 certain cores to reach higher turbo frequencies (when running 1036 single threaded workloads) than others. 1037 1038 Enabling this kernel feature teaches the scheduler about 1039 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1040 scheduler's CPU selection logic accordingly, so that higher 1041 overall system performance can be achieved. 1042 1043 This feature will have no effect on CPUs without this feature. 1044 1045 If unsure say Y here. 1046 1047source "kernel/Kconfig.preempt" 1048 1049config UP_LATE_INIT 1050 def_bool y 1051 depends on !SMP && X86_LOCAL_APIC 1052 1053config X86_UP_APIC 1054 bool "Local APIC support on uniprocessors" if !PCI_MSI 1055 default PCI_MSI 1056 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1057 ---help--- 1058 A local APIC (Advanced Programmable Interrupt Controller) is an 1059 integrated interrupt controller in the CPU. If you have a single-CPU 1060 system which has a processor with a local APIC, you can say Y here to 1061 enable and use it. If you say Y here even though your machine doesn't 1062 have a local APIC, then the kernel will still run with no slowdown at 1063 all. The local APIC supports CPU-generated self-interrupts (timer, 1064 performance counters), and the NMI watchdog which detects hard 1065 lockups. 1066 1067config X86_UP_IOAPIC 1068 bool "IO-APIC support on uniprocessors" 1069 depends on X86_UP_APIC 1070 ---help--- 1071 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1072 SMP-capable replacement for PC-style interrupt controllers. Most 1073 SMP systems and many recent uniprocessor systems have one. 1074 1075 If you have a single-CPU system with an IO-APIC, you can say Y here 1076 to use it. If you say Y here even though your machine doesn't have 1077 an IO-APIC, then the kernel will still run with no slowdown at all. 1078 1079config X86_LOCAL_APIC 1080 def_bool y 1081 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1082 select IRQ_DOMAIN_HIERARCHY 1083 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1084 1085config X86_IO_APIC 1086 def_bool y 1087 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1088 1089config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1090 bool "Reroute for broken boot IRQs" 1091 depends on X86_IO_APIC 1092 ---help--- 1093 This option enables a workaround that fixes a source of 1094 spurious interrupts. This is recommended when threaded 1095 interrupt handling is used on systems where the generation of 1096 superfluous "boot interrupts" cannot be disabled. 1097 1098 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1099 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1100 kernel does during interrupt handling). On chipsets where this 1101 boot IRQ generation cannot be disabled, this workaround keeps 1102 the original IRQ line masked so that only the equivalent "boot 1103 IRQ" is delivered to the CPUs. The workaround also tells the 1104 kernel to set up the IRQ handler on the boot IRQ line. In this 1105 way only one interrupt is delivered to the kernel. Otherwise 1106 the spurious second interrupt may cause the kernel to bring 1107 down (vital) interrupt lines. 1108 1109 Only affects "broken" chipsets. Interrupt sharing may be 1110 increased on these systems. 1111 1112config X86_MCE 1113 bool "Machine Check / overheating reporting" 1114 select GENERIC_ALLOCATOR 1115 default y 1116 ---help--- 1117 Machine Check support allows the processor to notify the 1118 kernel if it detects a problem (e.g. overheating, data corruption). 1119 The action the kernel takes depends on the severity of the problem, 1120 ranging from warning messages to halting the machine. 1121 1122config X86_MCELOG_LEGACY 1123 bool "Support for deprecated /dev/mcelog character device" 1124 depends on X86_MCE 1125 ---help--- 1126 Enable support for /dev/mcelog which is needed by the old mcelog 1127 userspace logging daemon. Consider switching to the new generation 1128 rasdaemon solution. 1129 1130config X86_MCE_INTEL 1131 def_bool y 1132 prompt "Intel MCE features" 1133 depends on X86_MCE && X86_LOCAL_APIC 1134 ---help--- 1135 Additional support for intel specific MCE features such as 1136 the thermal monitor. 1137 1138config X86_MCE_AMD 1139 def_bool y 1140 prompt "AMD MCE features" 1141 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1142 ---help--- 1143 Additional support for AMD specific MCE features such as 1144 the DRAM Error Threshold. 1145 1146config X86_ANCIENT_MCE 1147 bool "Support for old Pentium 5 / WinChip machine checks" 1148 depends on X86_32 && X86_MCE 1149 ---help--- 1150 Include support for machine check handling on old Pentium 5 or WinChip 1151 systems. These typically need to be enabled explicitly on the command 1152 line. 1153 1154config X86_MCE_THRESHOLD 1155 depends on X86_MCE_AMD || X86_MCE_INTEL 1156 def_bool y 1157 1158config X86_MCE_INJECT 1159 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1160 tristate "Machine check injector support" 1161 ---help--- 1162 Provide support for injecting machine checks for testing purposes. 1163 If you don't know what a machine check is and you don't do kernel 1164 QA it is safe to say n. 1165 1166config X86_THERMAL_VECTOR 1167 def_bool y 1168 depends on X86_MCE_INTEL 1169 1170source "arch/x86/events/Kconfig" 1171 1172config X86_LEGACY_VM86 1173 bool "Legacy VM86 support" 1174 default n 1175 depends on X86_32 1176 ---help--- 1177 This option allows user programs to put the CPU into V8086 1178 mode, which is an 80286-era approximation of 16-bit real mode. 1179 1180 Some very old versions of X and/or vbetool require this option 1181 for user mode setting. Similarly, DOSEMU will use it if 1182 available to accelerate real mode DOS programs. However, any 1183 recent version of DOSEMU, X, or vbetool should be fully 1184 functional even without kernel VM86 support, as they will all 1185 fall back to software emulation. Nevertheless, if you are using 1186 a 16-bit DOS program where 16-bit performance matters, vm86 1187 mode might be faster than emulation and you might want to 1188 enable this option. 1189 1190 Note that any app that works on a 64-bit kernel is unlikely to 1191 need this option, as 64-bit kernels don't, and can't, support 1192 V8086 mode. This option is also unrelated to 16-bit protected 1193 mode and is not needed to run most 16-bit programs under Wine. 1194 1195 Enabling this option increases the complexity of the kernel 1196 and slows down exception handling a tiny bit. 1197 1198 If unsure, say N here. 1199 1200config VM86 1201 bool 1202 default X86_LEGACY_VM86 1203 1204config X86_16BIT 1205 bool "Enable support for 16-bit segments" if EXPERT 1206 default y 1207 depends on MODIFY_LDT_SYSCALL 1208 ---help--- 1209 This option is required by programs like Wine to run 16-bit 1210 protected mode legacy code on x86 processors. Disabling 1211 this option saves about 300 bytes on i386, or around 6K text 1212 plus 16K runtime memory on x86-64, 1213 1214config X86_ESPFIX32 1215 def_bool y 1216 depends on X86_16BIT && X86_32 1217 1218config X86_ESPFIX64 1219 def_bool y 1220 depends on X86_16BIT && X86_64 1221 1222config X86_VSYSCALL_EMULATION 1223 bool "Enable vsyscall emulation" if EXPERT 1224 default y 1225 depends on X86_64 1226 ---help--- 1227 This enables emulation of the legacy vsyscall page. Disabling 1228 it is roughly equivalent to booting with vsyscall=none, except 1229 that it will also disable the helpful warning if a program 1230 tries to use a vsyscall. With this option set to N, offending 1231 programs will just segfault, citing addresses of the form 1232 0xffffffffff600?00. 1233 1234 This option is required by many programs built before 2013, and 1235 care should be used even with newer programs if set to N. 1236 1237 Disabling this option saves about 7K of kernel size and 1238 possibly 4K of additional runtime pagetable memory. 1239 1240config TOSHIBA 1241 tristate "Toshiba Laptop support" 1242 depends on X86_32 1243 ---help--- 1244 This adds a driver to safely access the System Management Mode of 1245 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1246 not work on models with a Phoenix BIOS. The System Management Mode 1247 is used to set the BIOS and power saving options on Toshiba portables. 1248 1249 For information on utilities to make use of this driver see the 1250 Toshiba Linux utilities web site at: 1251 <http://www.buzzard.org.uk/toshiba/>. 1252 1253 Say Y if you intend to run this kernel on a Toshiba portable. 1254 Say N otherwise. 1255 1256config I8K 1257 tristate "Dell i8k legacy laptop support" 1258 select HWMON 1259 select SENSORS_DELL_SMM 1260 ---help--- 1261 This option enables legacy /proc/i8k userspace interface in hwmon 1262 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1263 temperature and allows controlling fan speeds of Dell laptops via 1264 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1265 it reports also power and hotkey status. For fan speed control is 1266 needed userspace package i8kutils. 1267 1268 Say Y if you intend to run this kernel on old Dell laptops or want to 1269 use userspace package i8kutils. 1270 Say N otherwise. 1271 1272config X86_REBOOTFIXUPS 1273 bool "Enable X86 board specific fixups for reboot" 1274 depends on X86_32 1275 ---help--- 1276 This enables chipset and/or board specific fixups to be done 1277 in order to get reboot to work correctly. This is only needed on 1278 some combinations of hardware and BIOS. The symptom, for which 1279 this config is intended, is when reboot ends with a stalled/hung 1280 system. 1281 1282 Currently, the only fixup is for the Geode machines using 1283 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1284 1285 Say Y if you want to enable the fixup. Currently, it's safe to 1286 enable this option even if you don't need it. 1287 Say N otherwise. 1288 1289config MICROCODE 1290 bool "CPU microcode loading support" 1291 default y 1292 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1293 select FW_LOADER 1294 ---help--- 1295 If you say Y here, you will be able to update the microcode on 1296 Intel and AMD processors. The Intel support is for the IA32 family, 1297 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1298 AMD support is for families 0x10 and later. You will obviously need 1299 the actual microcode binary data itself which is not shipped with 1300 the Linux kernel. 1301 1302 The preferred method to load microcode from a detached initrd is described 1303 in Documentation/x86/microcode.txt. For that you need to enable 1304 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1305 initrd for microcode blobs. 1306 1307 In addition, you can build the microcode into the kernel. For that you 1308 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1309 config option. 1310 1311config MICROCODE_INTEL 1312 bool "Intel microcode loading support" 1313 depends on MICROCODE 1314 default MICROCODE 1315 select FW_LOADER 1316 ---help--- 1317 This options enables microcode patch loading support for Intel 1318 processors. 1319 1320 For the current Intel microcode data package go to 1321 <https://downloadcenter.intel.com> and search for 1322 'Linux Processor Microcode Data File'. 1323 1324config MICROCODE_AMD 1325 bool "AMD microcode loading support" 1326 depends on MICROCODE 1327 select FW_LOADER 1328 ---help--- 1329 If you select this option, microcode patch loading support for AMD 1330 processors will be enabled. 1331 1332config MICROCODE_OLD_INTERFACE 1333 def_bool y 1334 depends on MICROCODE 1335 1336config X86_MSR 1337 tristate "/dev/cpu/*/msr - Model-specific register support" 1338 ---help--- 1339 This device gives privileged processes access to the x86 1340 Model-Specific Registers (MSRs). It is a character device with 1341 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1342 MSR accesses are directed to a specific CPU on multi-processor 1343 systems. 1344 1345config X86_CPUID 1346 tristate "/dev/cpu/*/cpuid - CPU information support" 1347 ---help--- 1348 This device gives processes access to the x86 CPUID instruction to 1349 be executed on a specific processor. It is a character device 1350 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1351 /dev/cpu/31/cpuid. 1352 1353choice 1354 prompt "High Memory Support" 1355 default HIGHMEM4G 1356 depends on X86_32 1357 1358config NOHIGHMEM 1359 bool "off" 1360 ---help--- 1361 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1362 However, the address space of 32-bit x86 processors is only 4 1363 Gigabytes large. That means that, if you have a large amount of 1364 physical memory, not all of it can be "permanently mapped" by the 1365 kernel. The physical memory that's not permanently mapped is called 1366 "high memory". 1367 1368 If you are compiling a kernel which will never run on a machine with 1369 more than 1 Gigabyte total physical RAM, answer "off" here (default 1370 choice and suitable for most users). This will result in a "3GB/1GB" 1371 split: 3GB are mapped so that each process sees a 3GB virtual memory 1372 space and the remaining part of the 4GB virtual memory space is used 1373 by the kernel to permanently map as much physical memory as 1374 possible. 1375 1376 If the machine has between 1 and 4 Gigabytes physical RAM, then 1377 answer "4GB" here. 1378 1379 If more than 4 Gigabytes is used then answer "64GB" here. This 1380 selection turns Intel PAE (Physical Address Extension) mode on. 1381 PAE implements 3-level paging on IA32 processors. PAE is fully 1382 supported by Linux, PAE mode is implemented on all recent Intel 1383 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1384 then the kernel will not boot on CPUs that don't support PAE! 1385 1386 The actual amount of total physical memory will either be 1387 auto detected or can be forced by using a kernel command line option 1388 such as "mem=256M". (Try "man bootparam" or see the documentation of 1389 your boot loader (lilo or loadlin) about how to pass options to the 1390 kernel at boot time.) 1391 1392 If unsure, say "off". 1393 1394config HIGHMEM4G 1395 bool "4GB" 1396 ---help--- 1397 Select this if you have a 32-bit processor and between 1 and 4 1398 gigabytes of physical RAM. 1399 1400config HIGHMEM64G 1401 bool "64GB" 1402 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1403 select X86_PAE 1404 ---help--- 1405 Select this if you have a 32-bit processor and more than 4 1406 gigabytes of physical RAM. 1407 1408endchoice 1409 1410choice 1411 prompt "Memory split" if EXPERT 1412 default VMSPLIT_3G 1413 depends on X86_32 1414 ---help--- 1415 Select the desired split between kernel and user memory. 1416 1417 If the address range available to the kernel is less than the 1418 physical memory installed, the remaining memory will be available 1419 as "high memory". Accessing high memory is a little more costly 1420 than low memory, as it needs to be mapped into the kernel first. 1421 Note that increasing the kernel address space limits the range 1422 available to user programs, making the address space there 1423 tighter. Selecting anything other than the default 3G/1G split 1424 will also likely make your kernel incompatible with binary-only 1425 kernel modules. 1426 1427 If you are not absolutely sure what you are doing, leave this 1428 option alone! 1429 1430 config VMSPLIT_3G 1431 bool "3G/1G user/kernel split" 1432 config VMSPLIT_3G_OPT 1433 depends on !X86_PAE 1434 bool "3G/1G user/kernel split (for full 1G low memory)" 1435 config VMSPLIT_2G 1436 bool "2G/2G user/kernel split" 1437 config VMSPLIT_2G_OPT 1438 depends on !X86_PAE 1439 bool "2G/2G user/kernel split (for full 2G low memory)" 1440 config VMSPLIT_1G 1441 bool "1G/3G user/kernel split" 1442endchoice 1443 1444config PAGE_OFFSET 1445 hex 1446 default 0xB0000000 if VMSPLIT_3G_OPT 1447 default 0x80000000 if VMSPLIT_2G 1448 default 0x78000000 if VMSPLIT_2G_OPT 1449 default 0x40000000 if VMSPLIT_1G 1450 default 0xC0000000 1451 depends on X86_32 1452 1453config HIGHMEM 1454 def_bool y 1455 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1456 1457config X86_PAE 1458 bool "PAE (Physical Address Extension) Support" 1459 depends on X86_32 && !HIGHMEM4G 1460 select PHYS_ADDR_T_64BIT 1461 select SWIOTLB 1462 ---help--- 1463 PAE is required for NX support, and furthermore enables 1464 larger swapspace support for non-overcommit purposes. It 1465 has the cost of more pagetable lookup overhead, and also 1466 consumes more pagetable space per process. 1467 1468config X86_5LEVEL 1469 bool "Enable 5-level page tables support" 1470 select DYNAMIC_MEMORY_LAYOUT 1471 select SPARSEMEM_VMEMMAP 1472 depends on X86_64 1473 ---help--- 1474 5-level paging enables access to larger address space: 1475 upto 128 PiB of virtual address space and 4 PiB of 1476 physical address space. 1477 1478 It will be supported by future Intel CPUs. 1479 1480 A kernel with the option enabled can be booted on machines that 1481 support 4- or 5-level paging. 1482 1483 See Documentation/x86/x86_64/5level-paging.txt for more 1484 information. 1485 1486 Say N if unsure. 1487 1488config X86_DIRECT_GBPAGES 1489 def_bool y 1490 depends on X86_64 && !DEBUG_PAGEALLOC 1491 ---help--- 1492 Certain kernel features effectively disable kernel 1493 linear 1 GB mappings (even if the CPU otherwise 1494 supports them), so don't confuse the user by printing 1495 that we have them enabled. 1496 1497config ARCH_HAS_MEM_ENCRYPT 1498 def_bool y 1499 1500config AMD_MEM_ENCRYPT 1501 bool "AMD Secure Memory Encryption (SME) support" 1502 depends on X86_64 && CPU_SUP_AMD 1503 select DYNAMIC_PHYSICAL_MASK 1504 ---help--- 1505 Say yes to enable support for the encryption of system memory. 1506 This requires an AMD processor that supports Secure Memory 1507 Encryption (SME). 1508 1509config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1510 bool "Activate AMD Secure Memory Encryption (SME) by default" 1511 default y 1512 depends on AMD_MEM_ENCRYPT 1513 ---help--- 1514 Say yes to have system memory encrypted by default if running on 1515 an AMD processor that supports Secure Memory Encryption (SME). 1516 1517 If set to Y, then the encryption of system memory can be 1518 deactivated with the mem_encrypt=off command line option. 1519 1520 If set to N, then the encryption of system memory can be 1521 activated with the mem_encrypt=on command line option. 1522 1523config ARCH_USE_MEMREMAP_PROT 1524 def_bool y 1525 depends on AMD_MEM_ENCRYPT 1526 1527# Common NUMA Features 1528config NUMA 1529 bool "Numa Memory Allocation and Scheduler Support" 1530 depends on SMP 1531 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1532 default y if X86_BIGSMP 1533 ---help--- 1534 Enable NUMA (Non Uniform Memory Access) support. 1535 1536 The kernel will try to allocate memory used by a CPU on the 1537 local memory controller of the CPU and add some more 1538 NUMA awareness to the kernel. 1539 1540 For 64-bit this is recommended if the system is Intel Core i7 1541 (or later), AMD Opteron, or EM64T NUMA. 1542 1543 For 32-bit this is only needed if you boot a 32-bit 1544 kernel on a 64-bit NUMA platform. 1545 1546 Otherwise, you should say N. 1547 1548config AMD_NUMA 1549 def_bool y 1550 prompt "Old style AMD Opteron NUMA detection" 1551 depends on X86_64 && NUMA && PCI 1552 ---help--- 1553 Enable AMD NUMA node topology detection. You should say Y here if 1554 you have a multi processor AMD system. This uses an old method to 1555 read the NUMA configuration directly from the builtin Northbridge 1556 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1557 which also takes priority if both are compiled in. 1558 1559config X86_64_ACPI_NUMA 1560 def_bool y 1561 prompt "ACPI NUMA detection" 1562 depends on X86_64 && NUMA && ACPI && PCI 1563 select ACPI_NUMA 1564 ---help--- 1565 Enable ACPI SRAT based node topology detection. 1566 1567# Some NUMA nodes have memory ranges that span 1568# other nodes. Even though a pfn is valid and 1569# between a node's start and end pfns, it may not 1570# reside on that node. See memmap_init_zone() 1571# for details. 1572config NODES_SPAN_OTHER_NODES 1573 def_bool y 1574 depends on X86_64_ACPI_NUMA 1575 1576config NUMA_EMU 1577 bool "NUMA emulation" 1578 depends on NUMA 1579 ---help--- 1580 Enable NUMA emulation. A flat machine will be split 1581 into virtual nodes when booted with "numa=fake=N", where N is the 1582 number of nodes. This is only useful for debugging. 1583 1584config NODES_SHIFT 1585 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1586 range 1 10 1587 default "10" if MAXSMP 1588 default "6" if X86_64 1589 default "3" 1590 depends on NEED_MULTIPLE_NODES 1591 ---help--- 1592 Specify the maximum number of NUMA Nodes available on the target 1593 system. Increases memory reserved to accommodate various tables. 1594 1595config ARCH_HAVE_MEMORY_PRESENT 1596 def_bool y 1597 depends on X86_32 && DISCONTIGMEM 1598 1599config ARCH_FLATMEM_ENABLE 1600 def_bool y 1601 depends on X86_32 && !NUMA 1602 1603config ARCH_DISCONTIGMEM_ENABLE 1604 def_bool y 1605 depends on NUMA && X86_32 1606 1607config ARCH_DISCONTIGMEM_DEFAULT 1608 def_bool y 1609 depends on NUMA && X86_32 1610 1611config ARCH_SPARSEMEM_ENABLE 1612 def_bool y 1613 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1614 select SPARSEMEM_STATIC if X86_32 1615 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1616 1617config ARCH_SPARSEMEM_DEFAULT 1618 def_bool y 1619 depends on X86_64 1620 1621config ARCH_SELECT_MEMORY_MODEL 1622 def_bool y 1623 depends on ARCH_SPARSEMEM_ENABLE 1624 1625config ARCH_MEMORY_PROBE 1626 bool "Enable sysfs memory/probe interface" 1627 depends on X86_64 && MEMORY_HOTPLUG 1628 help 1629 This option enables a sysfs memory/probe interface for testing. 1630 See Documentation/memory-hotplug.txt for more information. 1631 If you are unsure how to answer this question, answer N. 1632 1633config ARCH_PROC_KCORE_TEXT 1634 def_bool y 1635 depends on X86_64 && PROC_KCORE 1636 1637config ILLEGAL_POINTER_VALUE 1638 hex 1639 default 0 if X86_32 1640 default 0xdead000000000000 if X86_64 1641 1642source "mm/Kconfig" 1643 1644config X86_PMEM_LEGACY_DEVICE 1645 bool 1646 1647config X86_PMEM_LEGACY 1648 tristate "Support non-standard NVDIMMs and ADR protected memory" 1649 depends on PHYS_ADDR_T_64BIT 1650 depends on BLK_DEV 1651 select X86_PMEM_LEGACY_DEVICE 1652 select LIBNVDIMM 1653 help 1654 Treat memory marked using the non-standard e820 type of 12 as used 1655 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1656 The kernel will offer these regions to the 'pmem' driver so 1657 they can be used for persistent storage. 1658 1659 Say Y if unsure. 1660 1661config HIGHPTE 1662 bool "Allocate 3rd-level pagetables from highmem" 1663 depends on HIGHMEM 1664 ---help--- 1665 The VM uses one page table entry for each page of physical memory. 1666 For systems with a lot of RAM, this can be wasteful of precious 1667 low memory. Setting this option will put user-space page table 1668 entries in high memory. 1669 1670config X86_CHECK_BIOS_CORRUPTION 1671 bool "Check for low memory corruption" 1672 ---help--- 1673 Periodically check for memory corruption in low memory, which 1674 is suspected to be caused by BIOS. Even when enabled in the 1675 configuration, it is disabled at runtime. Enable it by 1676 setting "memory_corruption_check=1" on the kernel command 1677 line. By default it scans the low 64k of memory every 60 1678 seconds; see the memory_corruption_check_size and 1679 memory_corruption_check_period parameters in 1680 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1681 1682 When enabled with the default parameters, this option has 1683 almost no overhead, as it reserves a relatively small amount 1684 of memory and scans it infrequently. It both detects corruption 1685 and prevents it from affecting the running system. 1686 1687 It is, however, intended as a diagnostic tool; if repeatable 1688 BIOS-originated corruption always affects the same memory, 1689 you can use memmap= to prevent the kernel from using that 1690 memory. 1691 1692config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1693 bool "Set the default setting of memory_corruption_check" 1694 depends on X86_CHECK_BIOS_CORRUPTION 1695 default y 1696 ---help--- 1697 Set whether the default state of memory_corruption_check is 1698 on or off. 1699 1700config X86_RESERVE_LOW 1701 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1702 default 64 1703 range 4 640 1704 ---help--- 1705 Specify the amount of low memory to reserve for the BIOS. 1706 1707 The first page contains BIOS data structures that the kernel 1708 must not use, so that page must always be reserved. 1709 1710 By default we reserve the first 64K of physical RAM, as a 1711 number of BIOSes are known to corrupt that memory range 1712 during events such as suspend/resume or monitor cable 1713 insertion, so it must not be used by the kernel. 1714 1715 You can set this to 4 if you are absolutely sure that you 1716 trust the BIOS to get all its memory reservations and usages 1717 right. If you know your BIOS have problems beyond the 1718 default 64K area, you can set this to 640 to avoid using the 1719 entire low memory range. 1720 1721 If you have doubts about the BIOS (e.g. suspend/resume does 1722 not work or there's kernel crashes after certain hardware 1723 hotplug events) then you might want to enable 1724 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1725 typical corruption patterns. 1726 1727 Leave this to the default value of 64 if you are unsure. 1728 1729config MATH_EMULATION 1730 bool 1731 depends on MODIFY_LDT_SYSCALL 1732 prompt "Math emulation" if X86_32 1733 ---help--- 1734 Linux can emulate a math coprocessor (used for floating point 1735 operations) if you don't have one. 486DX and Pentium processors have 1736 a math coprocessor built in, 486SX and 386 do not, unless you added 1737 a 487DX or 387, respectively. (The messages during boot time can 1738 give you some hints here ["man dmesg"].) Everyone needs either a 1739 coprocessor or this emulation. 1740 1741 If you don't have a math coprocessor, you need to say Y here; if you 1742 say Y here even though you have a coprocessor, the coprocessor will 1743 be used nevertheless. (This behavior can be changed with the kernel 1744 command line option "no387", which comes handy if your coprocessor 1745 is broken. Try "man bootparam" or see the documentation of your boot 1746 loader (lilo or loadlin) about how to pass options to the kernel at 1747 boot time.) This means that it is a good idea to say Y here if you 1748 intend to use this kernel on different machines. 1749 1750 More information about the internals of the Linux math coprocessor 1751 emulation can be found in <file:arch/x86/math-emu/README>. 1752 1753 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1754 kernel, it won't hurt. 1755 1756config MTRR 1757 def_bool y 1758 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1759 ---help--- 1760 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1761 the Memory Type Range Registers (MTRRs) may be used to control 1762 processor access to memory ranges. This is most useful if you have 1763 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1764 allows bus write transfers to be combined into a larger transfer 1765 before bursting over the PCI/AGP bus. This can increase performance 1766 of image write operations 2.5 times or more. Saying Y here creates a 1767 /proc/mtrr file which may be used to manipulate your processor's 1768 MTRRs. Typically the X server should use this. 1769 1770 This code has a reasonably generic interface so that similar 1771 control registers on other processors can be easily supported 1772 as well: 1773 1774 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1775 Registers (ARRs) which provide a similar functionality to MTRRs. For 1776 these, the ARRs are used to emulate the MTRRs. 1777 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1778 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1779 write-combining. All of these processors are supported by this code 1780 and it makes sense to say Y here if you have one of them. 1781 1782 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1783 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1784 can lead to all sorts of problems, so it's good to say Y here. 1785 1786 You can safely say Y even if your machine doesn't have MTRRs, you'll 1787 just add about 9 KB to your kernel. 1788 1789 See <file:Documentation/x86/mtrr.txt> for more information. 1790 1791config MTRR_SANITIZER 1792 def_bool y 1793 prompt "MTRR cleanup support" 1794 depends on MTRR 1795 ---help--- 1796 Convert MTRR layout from continuous to discrete, so X drivers can 1797 add writeback entries. 1798 1799 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1800 The largest mtrr entry size for a continuous block can be set with 1801 mtrr_chunk_size. 1802 1803 If unsure, say Y. 1804 1805config MTRR_SANITIZER_ENABLE_DEFAULT 1806 int "MTRR cleanup enable value (0-1)" 1807 range 0 1 1808 default "0" 1809 depends on MTRR_SANITIZER 1810 ---help--- 1811 Enable mtrr cleanup default value 1812 1813config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1814 int "MTRR cleanup spare reg num (0-7)" 1815 range 0 7 1816 default "1" 1817 depends on MTRR_SANITIZER 1818 ---help--- 1819 mtrr cleanup spare entries default, it can be changed via 1820 mtrr_spare_reg_nr=N on the kernel command line. 1821 1822config X86_PAT 1823 def_bool y 1824 prompt "x86 PAT support" if EXPERT 1825 depends on MTRR 1826 ---help--- 1827 Use PAT attributes to setup page level cache control. 1828 1829 PATs are the modern equivalents of MTRRs and are much more 1830 flexible than MTRRs. 1831 1832 Say N here if you see bootup problems (boot crash, boot hang, 1833 spontaneous reboots) or a non-working video driver. 1834 1835 If unsure, say Y. 1836 1837config ARCH_USES_PG_UNCACHED 1838 def_bool y 1839 depends on X86_PAT 1840 1841config ARCH_RANDOM 1842 def_bool y 1843 prompt "x86 architectural random number generator" if EXPERT 1844 ---help--- 1845 Enable the x86 architectural RDRAND instruction 1846 (Intel Bull Mountain technology) to generate random numbers. 1847 If supported, this is a high bandwidth, cryptographically 1848 secure hardware random number generator. 1849 1850config X86_SMAP 1851 def_bool y 1852 prompt "Supervisor Mode Access Prevention" if EXPERT 1853 ---help--- 1854 Supervisor Mode Access Prevention (SMAP) is a security 1855 feature in newer Intel processors. There is a small 1856 performance cost if this enabled and turned on; there is 1857 also a small increase in the kernel size if this is enabled. 1858 1859 If unsure, say Y. 1860 1861config X86_INTEL_UMIP 1862 def_bool y 1863 depends on CPU_SUP_INTEL 1864 prompt "Intel User Mode Instruction Prevention" if EXPERT 1865 ---help--- 1866 The User Mode Instruction Prevention (UMIP) is a security 1867 feature in newer Intel processors. If enabled, a general 1868 protection fault is issued if the SGDT, SLDT, SIDT, SMSW 1869 or STR instructions are executed in user mode. These instructions 1870 unnecessarily expose information about the hardware state. 1871 1872 The vast majority of applications do not use these instructions. 1873 For the very few that do, software emulation is provided in 1874 specific cases in protected and virtual-8086 modes. Emulated 1875 results are dummy. 1876 1877config X86_INTEL_MPX 1878 prompt "Intel MPX (Memory Protection Extensions)" 1879 def_bool n 1880 # Note: only available in 64-bit mode due to VMA flags shortage 1881 depends on CPU_SUP_INTEL && X86_64 1882 select ARCH_USES_HIGH_VMA_FLAGS 1883 ---help--- 1884 MPX provides hardware features that can be used in 1885 conjunction with compiler-instrumented code to check 1886 memory references. It is designed to detect buffer 1887 overflow or underflow bugs. 1888 1889 This option enables running applications which are 1890 instrumented or otherwise use MPX. It does not use MPX 1891 itself inside the kernel or to protect the kernel 1892 against bad memory references. 1893 1894 Enabling this option will make the kernel larger: 1895 ~8k of kernel text and 36 bytes of data on a 64-bit 1896 defconfig. It adds a long to the 'mm_struct' which 1897 will increase the kernel memory overhead of each 1898 process and adds some branches to paths used during 1899 exec() and munmap(). 1900 1901 For details, see Documentation/x86/intel_mpx.txt 1902 1903 If unsure, say N. 1904 1905config X86_INTEL_MEMORY_PROTECTION_KEYS 1906 prompt "Intel Memory Protection Keys" 1907 def_bool y 1908 # Note: only available in 64-bit mode 1909 depends on CPU_SUP_INTEL && X86_64 1910 select ARCH_USES_HIGH_VMA_FLAGS 1911 select ARCH_HAS_PKEYS 1912 ---help--- 1913 Memory Protection Keys provides a mechanism for enforcing 1914 page-based protections, but without requiring modification of the 1915 page tables when an application changes protection domains. 1916 1917 For details, see Documentation/x86/protection-keys.txt 1918 1919 If unsure, say y. 1920 1921config EFI 1922 bool "EFI runtime service support" 1923 depends on ACPI 1924 select UCS2_STRING 1925 select EFI_RUNTIME_WRAPPERS 1926 ---help--- 1927 This enables the kernel to use EFI runtime services that are 1928 available (such as the EFI variable services). 1929 1930 This option is only useful on systems that have EFI firmware. 1931 In addition, you should use the latest ELILO loader available 1932 at <http://elilo.sourceforge.net> in order to take advantage 1933 of EFI runtime services. However, even with this option, the 1934 resultant kernel should continue to boot on existing non-EFI 1935 platforms. 1936 1937config EFI_STUB 1938 bool "EFI stub support" 1939 depends on EFI && !X86_USE_3DNOW 1940 select RELOCATABLE 1941 ---help--- 1942 This kernel feature allows a bzImage to be loaded directly 1943 by EFI firmware without the use of a bootloader. 1944 1945 See Documentation/efi-stub.txt for more information. 1946 1947config EFI_MIXED 1948 bool "EFI mixed-mode support" 1949 depends on EFI_STUB && X86_64 1950 ---help--- 1951 Enabling this feature allows a 64-bit kernel to be booted 1952 on a 32-bit firmware, provided that your CPU supports 64-bit 1953 mode. 1954 1955 Note that it is not possible to boot a mixed-mode enabled 1956 kernel via the EFI boot stub - a bootloader that supports 1957 the EFI handover protocol must be used. 1958 1959 If unsure, say N. 1960 1961config SECCOMP 1962 def_bool y 1963 prompt "Enable seccomp to safely compute untrusted bytecode" 1964 ---help--- 1965 This kernel feature is useful for number crunching applications 1966 that may need to compute untrusted bytecode during their 1967 execution. By using pipes or other transports made available to 1968 the process as file descriptors supporting the read/write 1969 syscalls, it's possible to isolate those applications in 1970 their own address space using seccomp. Once seccomp is 1971 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 1972 and the task is only allowed to execute a few safe syscalls 1973 defined by each seccomp mode. 1974 1975 If unsure, say Y. Only embedded should say N here. 1976 1977source kernel/Kconfig.hz 1978 1979config KEXEC 1980 bool "kexec system call" 1981 select KEXEC_CORE 1982 ---help--- 1983 kexec is a system call that implements the ability to shutdown your 1984 current kernel, and to start another kernel. It is like a reboot 1985 but it is independent of the system firmware. And like a reboot 1986 you can start any kernel with it, not just Linux. 1987 1988 The name comes from the similarity to the exec system call. 1989 1990 It is an ongoing process to be certain the hardware in a machine 1991 is properly shutdown, so do not be surprised if this code does not 1992 initially work for you. As of this writing the exact hardware 1993 interface is strongly in flux, so no good recommendation can be 1994 made. 1995 1996config KEXEC_FILE 1997 bool "kexec file based system call" 1998 select KEXEC_CORE 1999 select BUILD_BIN2C 2000 depends on X86_64 2001 depends on CRYPTO=y 2002 depends on CRYPTO_SHA256=y 2003 ---help--- 2004 This is new version of kexec system call. This system call is 2005 file based and takes file descriptors as system call argument 2006 for kernel and initramfs as opposed to list of segments as 2007 accepted by previous system call. 2008 2009config ARCH_HAS_KEXEC_PURGATORY 2010 def_bool KEXEC_FILE 2011 2012config KEXEC_VERIFY_SIG 2013 bool "Verify kernel signature during kexec_file_load() syscall" 2014 depends on KEXEC_FILE 2015 ---help--- 2016 This option makes kernel signature verification mandatory for 2017 the kexec_file_load() syscall. 2018 2019 In addition to that option, you need to enable signature 2020 verification for the corresponding kernel image type being 2021 loaded in order for this to work. 2022 2023config KEXEC_BZIMAGE_VERIFY_SIG 2024 bool "Enable bzImage signature verification support" 2025 depends on KEXEC_VERIFY_SIG 2026 depends on SIGNED_PE_FILE_VERIFICATION 2027 select SYSTEM_TRUSTED_KEYRING 2028 ---help--- 2029 Enable bzImage signature verification support. 2030 2031config CRASH_DUMP 2032 bool "kernel crash dumps" 2033 depends on X86_64 || (X86_32 && HIGHMEM) 2034 ---help--- 2035 Generate crash dump after being started by kexec. 2036 This should be normally only set in special crash dump kernels 2037 which are loaded in the main kernel with kexec-tools into 2038 a specially reserved region and then later executed after 2039 a crash by kdump/kexec. The crash dump kernel must be compiled 2040 to a memory address not used by the main kernel or BIOS using 2041 PHYSICAL_START, or it must be built as a relocatable image 2042 (CONFIG_RELOCATABLE=y). 2043 For more details see Documentation/kdump/kdump.txt 2044 2045config KEXEC_JUMP 2046 bool "kexec jump" 2047 depends on KEXEC && HIBERNATION 2048 ---help--- 2049 Jump between original kernel and kexeced kernel and invoke 2050 code in physical address mode via KEXEC 2051 2052config PHYSICAL_START 2053 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2054 default "0x1000000" 2055 ---help--- 2056 This gives the physical address where the kernel is loaded. 2057 2058 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2059 bzImage will decompress itself to above physical address and 2060 run from there. Otherwise, bzImage will run from the address where 2061 it has been loaded by the boot loader and will ignore above physical 2062 address. 2063 2064 In normal kdump cases one does not have to set/change this option 2065 as now bzImage can be compiled as a completely relocatable image 2066 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2067 address. This option is mainly useful for the folks who don't want 2068 to use a bzImage for capturing the crash dump and want to use a 2069 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2070 to be specifically compiled to run from a specific memory area 2071 (normally a reserved region) and this option comes handy. 2072 2073 So if you are using bzImage for capturing the crash dump, 2074 leave the value here unchanged to 0x1000000 and set 2075 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2076 for capturing the crash dump change this value to start of 2077 the reserved region. In other words, it can be set based on 2078 the "X" value as specified in the "crashkernel=YM@XM" 2079 command line boot parameter passed to the panic-ed 2080 kernel. Please take a look at Documentation/kdump/kdump.txt 2081 for more details about crash dumps. 2082 2083 Usage of bzImage for capturing the crash dump is recommended as 2084 one does not have to build two kernels. Same kernel can be used 2085 as production kernel and capture kernel. Above option should have 2086 gone away after relocatable bzImage support is introduced. But it 2087 is present because there are users out there who continue to use 2088 vmlinux for dump capture. This option should go away down the 2089 line. 2090 2091 Don't change this unless you know what you are doing. 2092 2093config RELOCATABLE 2094 bool "Build a relocatable kernel" 2095 default y 2096 ---help--- 2097 This builds a kernel image that retains relocation information 2098 so it can be loaded someplace besides the default 1MB. 2099 The relocations tend to make the kernel binary about 10% larger, 2100 but are discarded at runtime. 2101 2102 One use is for the kexec on panic case where the recovery kernel 2103 must live at a different physical address than the primary 2104 kernel. 2105 2106 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2107 it has been loaded at and the compile time physical address 2108 (CONFIG_PHYSICAL_START) is used as the minimum location. 2109 2110config RANDOMIZE_BASE 2111 bool "Randomize the address of the kernel image (KASLR)" 2112 depends on RELOCATABLE 2113 default y 2114 ---help--- 2115 In support of Kernel Address Space Layout Randomization (KASLR), 2116 this randomizes the physical address at which the kernel image 2117 is decompressed and the virtual address where the kernel 2118 image is mapped, as a security feature that deters exploit 2119 attempts relying on knowledge of the location of kernel 2120 code internals. 2121 2122 On 64-bit, the kernel physical and virtual addresses are 2123 randomized separately. The physical address will be anywhere 2124 between 16MB and the top of physical memory (up to 64TB). The 2125 virtual address will be randomized from 16MB up to 1GB (9 bits 2126 of entropy). Note that this also reduces the memory space 2127 available to kernel modules from 1.5GB to 1GB. 2128 2129 On 32-bit, the kernel physical and virtual addresses are 2130 randomized together. They will be randomized from 16MB up to 2131 512MB (8 bits of entropy). 2132 2133 Entropy is generated using the RDRAND instruction if it is 2134 supported. If RDTSC is supported, its value is mixed into 2135 the entropy pool as well. If neither RDRAND nor RDTSC are 2136 supported, then entropy is read from the i8254 timer. The 2137 usable entropy is limited by the kernel being built using 2138 2GB addressing, and that PHYSICAL_ALIGN must be at a 2139 minimum of 2MB. As a result, only 10 bits of entropy are 2140 theoretically possible, but the implementations are further 2141 limited due to memory layouts. 2142 2143 If unsure, say Y. 2144 2145# Relocation on x86 needs some additional build support 2146config X86_NEED_RELOCS 2147 def_bool y 2148 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2149 2150config PHYSICAL_ALIGN 2151 hex "Alignment value to which kernel should be aligned" 2152 default "0x200000" 2153 range 0x2000 0x1000000 if X86_32 2154 range 0x200000 0x1000000 if X86_64 2155 ---help--- 2156 This value puts the alignment restrictions on physical address 2157 where kernel is loaded and run from. Kernel is compiled for an 2158 address which meets above alignment restriction. 2159 2160 If bootloader loads the kernel at a non-aligned address and 2161 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2162 address aligned to above value and run from there. 2163 2164 If bootloader loads the kernel at a non-aligned address and 2165 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2166 load address and decompress itself to the address it has been 2167 compiled for and run from there. The address for which kernel is 2168 compiled already meets above alignment restrictions. Hence the 2169 end result is that kernel runs from a physical address meeting 2170 above alignment restrictions. 2171 2172 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2173 this value must be a multiple of 0x200000. 2174 2175 Don't change this unless you know what you are doing. 2176 2177config DYNAMIC_MEMORY_LAYOUT 2178 bool 2179 ---help--- 2180 This option makes base addresses of vmalloc and vmemmap as well as 2181 __PAGE_OFFSET movable during boot. 2182 2183config RANDOMIZE_MEMORY 2184 bool "Randomize the kernel memory sections" 2185 depends on X86_64 2186 depends on RANDOMIZE_BASE 2187 select DYNAMIC_MEMORY_LAYOUT 2188 default RANDOMIZE_BASE 2189 ---help--- 2190 Randomizes the base virtual address of kernel memory sections 2191 (physical memory mapping, vmalloc & vmemmap). This security feature 2192 makes exploits relying on predictable memory locations less reliable. 2193 2194 The order of allocations remains unchanged. Entropy is generated in 2195 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2196 configuration have in average 30,000 different possible virtual 2197 addresses for each memory section. 2198 2199 If unsure, say Y. 2200 2201config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2202 hex "Physical memory mapping padding" if EXPERT 2203 depends on RANDOMIZE_MEMORY 2204 default "0xa" if MEMORY_HOTPLUG 2205 default "0x0" 2206 range 0x1 0x40 if MEMORY_HOTPLUG 2207 range 0x0 0x40 2208 ---help--- 2209 Define the padding in terabytes added to the existing physical 2210 memory size during kernel memory randomization. It is useful 2211 for memory hotplug support but reduces the entropy available for 2212 address randomization. 2213 2214 If unsure, leave at the default value. 2215 2216config HOTPLUG_CPU 2217 bool "Support for hot-pluggable CPUs" 2218 depends on SMP 2219 ---help--- 2220 Say Y here to allow turning CPUs off and on. CPUs can be 2221 controlled through /sys/devices/system/cpu. 2222 ( Note: power management support will enable this option 2223 automatically on SMP systems. ) 2224 Say N if you want to disable CPU hotplug. 2225 2226config BOOTPARAM_HOTPLUG_CPU0 2227 bool "Set default setting of cpu0_hotpluggable" 2228 default n 2229 depends on HOTPLUG_CPU 2230 ---help--- 2231 Set whether default state of cpu0_hotpluggable is on or off. 2232 2233 Say Y here to enable CPU0 hotplug by default. If this switch 2234 is turned on, there is no need to give cpu0_hotplug kernel 2235 parameter and the CPU0 hotplug feature is enabled by default. 2236 2237 Please note: there are two known CPU0 dependencies if you want 2238 to enable the CPU0 hotplug feature either by this switch or by 2239 cpu0_hotplug kernel parameter. 2240 2241 First, resume from hibernate or suspend always starts from CPU0. 2242 So hibernate and suspend are prevented if CPU0 is offline. 2243 2244 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2245 offline if any interrupt can not migrate out of CPU0. There may 2246 be other CPU0 dependencies. 2247 2248 Please make sure the dependencies are under your control before 2249 you enable this feature. 2250 2251 Say N if you don't want to enable CPU0 hotplug feature by default. 2252 You still can enable the CPU0 hotplug feature at boot by kernel 2253 parameter cpu0_hotplug. 2254 2255config DEBUG_HOTPLUG_CPU0 2256 def_bool n 2257 prompt "Debug CPU0 hotplug" 2258 depends on HOTPLUG_CPU 2259 ---help--- 2260 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2261 soon as possible and boots up userspace with CPU0 offlined. User 2262 can online CPU0 back after boot time. 2263 2264 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2265 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2266 compilation or giving cpu0_hotplug kernel parameter at boot. 2267 2268 If unsure, say N. 2269 2270config COMPAT_VDSO 2271 def_bool n 2272 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2273 depends on COMPAT_32 2274 ---help--- 2275 Certain buggy versions of glibc will crash if they are 2276 presented with a 32-bit vDSO that is not mapped at the address 2277 indicated in its segment table. 2278 2279 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2280 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2281 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2282 the only released version with the bug, but OpenSUSE 9 2283 contains a buggy "glibc 2.3.2". 2284 2285 The symptom of the bug is that everything crashes on startup, saying: 2286 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2287 2288 Saying Y here changes the default value of the vdso32 boot 2289 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2290 This works around the glibc bug but hurts performance. 2291 2292 If unsure, say N: if you are compiling your own kernel, you 2293 are unlikely to be using a buggy version of glibc. 2294 2295choice 2296 prompt "vsyscall table for legacy applications" 2297 depends on X86_64 2298 default LEGACY_VSYSCALL_EMULATE 2299 help 2300 Legacy user code that does not know how to find the vDSO expects 2301 to be able to issue three syscalls by calling fixed addresses in 2302 kernel space. Since this location is not randomized with ASLR, 2303 it can be used to assist security vulnerability exploitation. 2304 2305 This setting can be changed at boot time via the kernel command 2306 line parameter vsyscall=[emulate|none]. 2307 2308 On a system with recent enough glibc (2.14 or newer) and no 2309 static binaries, you can say None without a performance penalty 2310 to improve security. 2311 2312 If unsure, select "Emulate". 2313 2314 config LEGACY_VSYSCALL_EMULATE 2315 bool "Emulate" 2316 help 2317 The kernel traps and emulates calls into the fixed 2318 vsyscall address mapping. This makes the mapping 2319 non-executable, but it still contains known contents, 2320 which could be used in certain rare security vulnerability 2321 exploits. This configuration is recommended when userspace 2322 still uses the vsyscall area. 2323 2324 config LEGACY_VSYSCALL_NONE 2325 bool "None" 2326 help 2327 There will be no vsyscall mapping at all. This will 2328 eliminate any risk of ASLR bypass due to the vsyscall 2329 fixed address mapping. Attempts to use the vsyscalls 2330 will be reported to dmesg, so that either old or 2331 malicious userspace programs can be identified. 2332 2333endchoice 2334 2335config CMDLINE_BOOL 2336 bool "Built-in kernel command line" 2337 ---help--- 2338 Allow for specifying boot arguments to the kernel at 2339 build time. On some systems (e.g. embedded ones), it is 2340 necessary or convenient to provide some or all of the 2341 kernel boot arguments with the kernel itself (that is, 2342 to not rely on the boot loader to provide them.) 2343 2344 To compile command line arguments into the kernel, 2345 set this option to 'Y', then fill in the 2346 boot arguments in CONFIG_CMDLINE. 2347 2348 Systems with fully functional boot loaders (i.e. non-embedded) 2349 should leave this option set to 'N'. 2350 2351config CMDLINE 2352 string "Built-in kernel command string" 2353 depends on CMDLINE_BOOL 2354 default "" 2355 ---help--- 2356 Enter arguments here that should be compiled into the kernel 2357 image and used at boot time. If the boot loader provides a 2358 command line at boot time, it is appended to this string to 2359 form the full kernel command line, when the system boots. 2360 2361 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2362 change this behavior. 2363 2364 In most cases, the command line (whether built-in or provided 2365 by the boot loader) should specify the device for the root 2366 file system. 2367 2368config CMDLINE_OVERRIDE 2369 bool "Built-in command line overrides boot loader arguments" 2370 depends on CMDLINE_BOOL 2371 ---help--- 2372 Set this option to 'Y' to have the kernel ignore the boot loader 2373 command line, and use ONLY the built-in command line. 2374 2375 This is used to work around broken boot loaders. This should 2376 be set to 'N' under normal conditions. 2377 2378config MODIFY_LDT_SYSCALL 2379 bool "Enable the LDT (local descriptor table)" if EXPERT 2380 default y 2381 ---help--- 2382 Linux can allow user programs to install a per-process x86 2383 Local Descriptor Table (LDT) using the modify_ldt(2) system 2384 call. This is required to run 16-bit or segmented code such as 2385 DOSEMU or some Wine programs. It is also used by some very old 2386 threading libraries. 2387 2388 Enabling this feature adds a small amount of overhead to 2389 context switches and increases the low-level kernel attack 2390 surface. Disabling it removes the modify_ldt(2) system call. 2391 2392 Saying 'N' here may make sense for embedded or server kernels. 2393 2394source "kernel/livepatch/Kconfig" 2395 2396endmenu 2397 2398config ARCH_HAS_ADD_PAGES 2399 def_bool y 2400 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2401 2402config ARCH_ENABLE_MEMORY_HOTPLUG 2403 def_bool y 2404 depends on X86_64 || (X86_32 && HIGHMEM) 2405 2406config ARCH_ENABLE_MEMORY_HOTREMOVE 2407 def_bool y 2408 depends on MEMORY_HOTPLUG 2409 2410config USE_PERCPU_NUMA_NODE_ID 2411 def_bool y 2412 depends on NUMA 2413 2414config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2415 def_bool y 2416 depends on X86_64 || X86_PAE 2417 2418config ARCH_ENABLE_HUGEPAGE_MIGRATION 2419 def_bool y 2420 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2421 2422config ARCH_ENABLE_THP_MIGRATION 2423 def_bool y 2424 depends on X86_64 && TRANSPARENT_HUGEPAGE 2425 2426menu "Power management and ACPI options" 2427 2428config ARCH_HIBERNATION_HEADER 2429 def_bool y 2430 depends on X86_64 && HIBERNATION 2431 2432source "kernel/power/Kconfig" 2433 2434source "drivers/acpi/Kconfig" 2435 2436source "drivers/sfi/Kconfig" 2437 2438config X86_APM_BOOT 2439 def_bool y 2440 depends on APM 2441 2442menuconfig APM 2443 tristate "APM (Advanced Power Management) BIOS support" 2444 depends on X86_32 && PM_SLEEP 2445 ---help--- 2446 APM is a BIOS specification for saving power using several different 2447 techniques. This is mostly useful for battery powered laptops with 2448 APM compliant BIOSes. If you say Y here, the system time will be 2449 reset after a RESUME operation, the /proc/apm device will provide 2450 battery status information, and user-space programs will receive 2451 notification of APM "events" (e.g. battery status change). 2452 2453 If you select "Y" here, you can disable actual use of the APM 2454 BIOS by passing the "apm=off" option to the kernel at boot time. 2455 2456 Note that the APM support is almost completely disabled for 2457 machines with more than one CPU. 2458 2459 In order to use APM, you will need supporting software. For location 2460 and more information, read <file:Documentation/power/apm-acpi.txt> 2461 and the Battery Powered Linux mini-HOWTO, available from 2462 <http://www.tldp.org/docs.html#howto>. 2463 2464 This driver does not spin down disk drives (see the hdparm(8) 2465 manpage ("man 8 hdparm") for that), and it doesn't turn off 2466 VESA-compliant "green" monitors. 2467 2468 This driver does not support the TI 4000M TravelMate and the ACER 2469 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2470 desktop machines also don't have compliant BIOSes, and this driver 2471 may cause those machines to panic during the boot phase. 2472 2473 Generally, if you don't have a battery in your machine, there isn't 2474 much point in using this driver and you should say N. If you get 2475 random kernel OOPSes or reboots that don't seem to be related to 2476 anything, try disabling/enabling this option (or disabling/enabling 2477 APM in your BIOS). 2478 2479 Some other things you should try when experiencing seemingly random, 2480 "weird" problems: 2481 2482 1) make sure that you have enough swap space and that it is 2483 enabled. 2484 2) pass the "no-hlt" option to the kernel 2485 3) switch on floating point emulation in the kernel and pass 2486 the "no387" option to the kernel 2487 4) pass the "floppy=nodma" option to the kernel 2488 5) pass the "mem=4M" option to the kernel (thereby disabling 2489 all but the first 4 MB of RAM) 2490 6) make sure that the CPU is not over clocked. 2491 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2492 8) disable the cache from your BIOS settings 2493 9) install a fan for the video card or exchange video RAM 2494 10) install a better fan for the CPU 2495 11) exchange RAM chips 2496 12) exchange the motherboard. 2497 2498 To compile this driver as a module, choose M here: the 2499 module will be called apm. 2500 2501if APM 2502 2503config APM_IGNORE_USER_SUSPEND 2504 bool "Ignore USER SUSPEND" 2505 ---help--- 2506 This option will ignore USER SUSPEND requests. On machines with a 2507 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2508 series notebooks, it is necessary to say Y because of a BIOS bug. 2509 2510config APM_DO_ENABLE 2511 bool "Enable PM at boot time" 2512 ---help--- 2513 Enable APM features at boot time. From page 36 of the APM BIOS 2514 specification: "When disabled, the APM BIOS does not automatically 2515 power manage devices, enter the Standby State, enter the Suspend 2516 State, or take power saving steps in response to CPU Idle calls." 2517 This driver will make CPU Idle calls when Linux is idle (unless this 2518 feature is turned off -- see "Do CPU IDLE calls", below). This 2519 should always save battery power, but more complicated APM features 2520 will be dependent on your BIOS implementation. You may need to turn 2521 this option off if your computer hangs at boot time when using APM 2522 support, or if it beeps continuously instead of suspending. Turn 2523 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2524 T400CDT. This is off by default since most machines do fine without 2525 this feature. 2526 2527config APM_CPU_IDLE 2528 depends on CPU_IDLE 2529 bool "Make CPU Idle calls when idle" 2530 ---help--- 2531 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2532 On some machines, this can activate improved power savings, such as 2533 a slowed CPU clock rate, when the machine is idle. These idle calls 2534 are made after the idle loop has run for some length of time (e.g., 2535 333 mS). On some machines, this will cause a hang at boot time or 2536 whenever the CPU becomes idle. (On machines with more than one CPU, 2537 this option does nothing.) 2538 2539config APM_DISPLAY_BLANK 2540 bool "Enable console blanking using APM" 2541 ---help--- 2542 Enable console blanking using the APM. Some laptops can use this to 2543 turn off the LCD backlight when the screen blanker of the Linux 2544 virtual console blanks the screen. Note that this is only used by 2545 the virtual console screen blanker, and won't turn off the backlight 2546 when using the X Window system. This also doesn't have anything to 2547 do with your VESA-compliant power-saving monitor. Further, this 2548 option doesn't work for all laptops -- it might not turn off your 2549 backlight at all, or it might print a lot of errors to the console, 2550 especially if you are using gpm. 2551 2552config APM_ALLOW_INTS 2553 bool "Allow interrupts during APM BIOS calls" 2554 ---help--- 2555 Normally we disable external interrupts while we are making calls to 2556 the APM BIOS as a measure to lessen the effects of a badly behaving 2557 BIOS implementation. The BIOS should reenable interrupts if it 2558 needs to. Unfortunately, some BIOSes do not -- especially those in 2559 many of the newer IBM Thinkpads. If you experience hangs when you 2560 suspend, try setting this to Y. Otherwise, say N. 2561 2562endif # APM 2563 2564source "drivers/cpufreq/Kconfig" 2565 2566source "drivers/cpuidle/Kconfig" 2567 2568source "drivers/idle/Kconfig" 2569 2570endmenu 2571 2572 2573menu "Bus options (PCI etc.)" 2574 2575config PCI 2576 bool "PCI support" 2577 default y 2578 ---help--- 2579 Find out whether you have a PCI motherboard. PCI is the name of a 2580 bus system, i.e. the way the CPU talks to the other stuff inside 2581 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or 2582 VESA. If you have PCI, say Y, otherwise N. 2583 2584choice 2585 prompt "PCI access mode" 2586 depends on X86_32 && PCI 2587 default PCI_GOANY 2588 ---help--- 2589 On PCI systems, the BIOS can be used to detect the PCI devices and 2590 determine their configuration. However, some old PCI motherboards 2591 have BIOS bugs and may crash if this is done. Also, some embedded 2592 PCI-based systems don't have any BIOS at all. Linux can also try to 2593 detect the PCI hardware directly without using the BIOS. 2594 2595 With this option, you can specify how Linux should detect the 2596 PCI devices. If you choose "BIOS", the BIOS will be used, 2597 if you choose "Direct", the BIOS won't be used, and if you 2598 choose "MMConfig", then PCI Express MMCONFIG will be used. 2599 If you choose "Any", the kernel will try MMCONFIG, then the 2600 direct access method and falls back to the BIOS if that doesn't 2601 work. If unsure, go with the default, which is "Any". 2602 2603config PCI_GOBIOS 2604 bool "BIOS" 2605 2606config PCI_GOMMCONFIG 2607 bool "MMConfig" 2608 2609config PCI_GODIRECT 2610 bool "Direct" 2611 2612config PCI_GOOLPC 2613 bool "OLPC XO-1" 2614 depends on OLPC 2615 2616config PCI_GOANY 2617 bool "Any" 2618 2619endchoice 2620 2621config PCI_BIOS 2622 def_bool y 2623 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2624 2625# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2626config PCI_DIRECT 2627 def_bool y 2628 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2629 2630config PCI_MMCONFIG 2631 bool "Support mmconfig PCI config space access" if X86_64 2632 default y 2633 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2634 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2635 2636config PCI_OLPC 2637 def_bool y 2638 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2639 2640config PCI_XEN 2641 def_bool y 2642 depends on PCI && XEN 2643 select SWIOTLB_XEN 2644 2645config PCI_DOMAINS 2646 def_bool y 2647 depends on PCI 2648 2649config MMCONF_FAM10H 2650 def_bool y 2651 depends on X86_64 && PCI_MMCONFIG && ACPI 2652 2653config PCI_CNB20LE_QUIRK 2654 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2655 depends on PCI 2656 help 2657 Read the PCI windows out of the CNB20LE host bridge. This allows 2658 PCI hotplug to work on systems with the CNB20LE chipset which do 2659 not have ACPI. 2660 2661 There's no public spec for this chipset, and this functionality 2662 is known to be incomplete. 2663 2664 You should say N unless you know you need this. 2665 2666source "drivers/pci/Kconfig" 2667 2668config ISA_BUS 2669 bool "ISA bus support on modern systems" if EXPERT 2670 help 2671 Expose ISA bus device drivers and options available for selection and 2672 configuration. Enable this option if your target machine has an ISA 2673 bus. ISA is an older system, displaced by PCI and newer bus 2674 architectures -- if your target machine is modern, it probably does 2675 not have an ISA bus. 2676 2677 If unsure, say N. 2678 2679# x86_64 have no ISA slots, but can have ISA-style DMA. 2680config ISA_DMA_API 2681 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2682 default y 2683 help 2684 Enables ISA-style DMA support for devices requiring such controllers. 2685 If unsure, say Y. 2686 2687if X86_32 2688 2689config ISA 2690 bool "ISA support" 2691 ---help--- 2692 Find out whether you have ISA slots on your motherboard. ISA is the 2693 name of a bus system, i.e. the way the CPU talks to the other stuff 2694 inside your box. Other bus systems are PCI, EISA, MicroChannel 2695 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2696 newer boards don't support it. If you have ISA, say Y, otherwise N. 2697 2698config EISA 2699 bool "EISA support" 2700 depends on ISA 2701 ---help--- 2702 The Extended Industry Standard Architecture (EISA) bus was 2703 developed as an open alternative to the IBM MicroChannel bus. 2704 2705 The EISA bus provided some of the features of the IBM MicroChannel 2706 bus while maintaining backward compatibility with cards made for 2707 the older ISA bus. The EISA bus saw limited use between 1988 and 2708 1995 when it was made obsolete by the PCI bus. 2709 2710 Say Y here if you are building a kernel for an EISA-based machine. 2711 2712 Otherwise, say N. 2713 2714source "drivers/eisa/Kconfig" 2715 2716config SCx200 2717 tristate "NatSemi SCx200 support" 2718 ---help--- 2719 This provides basic support for National Semiconductor's 2720 (now AMD's) Geode processors. The driver probes for the 2721 PCI-IDs of several on-chip devices, so its a good dependency 2722 for other scx200_* drivers. 2723 2724 If compiled as a module, the driver is named scx200. 2725 2726config SCx200HR_TIMER 2727 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2728 depends on SCx200 2729 default y 2730 ---help--- 2731 This driver provides a clocksource built upon the on-chip 2732 27MHz high-resolution timer. Its also a workaround for 2733 NSC Geode SC-1100's buggy TSC, which loses time when the 2734 processor goes idle (as is done by the scheduler). The 2735 other workaround is idle=poll boot option. 2736 2737config OLPC 2738 bool "One Laptop Per Child support" 2739 depends on !X86_PAE 2740 select GPIOLIB 2741 select OF 2742 select OF_PROMTREE 2743 select IRQ_DOMAIN 2744 ---help--- 2745 Add support for detecting the unique features of the OLPC 2746 XO hardware. 2747 2748config OLPC_XO1_PM 2749 bool "OLPC XO-1 Power Management" 2750 depends on OLPC && MFD_CS5535 && PM_SLEEP 2751 select MFD_CORE 2752 ---help--- 2753 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2754 2755config OLPC_XO1_RTC 2756 bool "OLPC XO-1 Real Time Clock" 2757 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2758 ---help--- 2759 Add support for the XO-1 real time clock, which can be used as a 2760 programmable wakeup source. 2761 2762config OLPC_XO1_SCI 2763 bool "OLPC XO-1 SCI extras" 2764 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2765 depends on INPUT=y 2766 select POWER_SUPPLY 2767 ---help--- 2768 Add support for SCI-based features of the OLPC XO-1 laptop: 2769 - EC-driven system wakeups 2770 - Power button 2771 - Ebook switch 2772 - Lid switch 2773 - AC adapter status updates 2774 - Battery status updates 2775 2776config OLPC_XO15_SCI 2777 bool "OLPC XO-1.5 SCI extras" 2778 depends on OLPC && ACPI 2779 select POWER_SUPPLY 2780 ---help--- 2781 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2782 - EC-driven system wakeups 2783 - AC adapter status updates 2784 - Battery status updates 2785 2786config ALIX 2787 bool "PCEngines ALIX System Support (LED setup)" 2788 select GPIOLIB 2789 ---help--- 2790 This option enables system support for the PCEngines ALIX. 2791 At present this just sets up LEDs for GPIO control on 2792 ALIX2/3/6 boards. However, other system specific setup should 2793 get added here. 2794 2795 Note: You must still enable the drivers for GPIO and LED support 2796 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2797 2798 Note: You have to set alix.force=1 for boards with Award BIOS. 2799 2800config NET5501 2801 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2802 select GPIOLIB 2803 ---help--- 2804 This option enables system support for the Soekris Engineering net5501. 2805 2806config GEOS 2807 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2808 select GPIOLIB 2809 depends on DMI 2810 ---help--- 2811 This option enables system support for the Traverse Technologies GEOS. 2812 2813config TS5500 2814 bool "Technologic Systems TS-5500 platform support" 2815 depends on MELAN 2816 select CHECK_SIGNATURE 2817 select NEW_LEDS 2818 select LEDS_CLASS 2819 ---help--- 2820 This option enables system support for the Technologic Systems TS-5500. 2821 2822endif # X86_32 2823 2824config AMD_NB 2825 def_bool y 2826 depends on CPU_SUP_AMD && PCI 2827 2828source "drivers/pcmcia/Kconfig" 2829 2830config RAPIDIO 2831 tristate "RapidIO support" 2832 depends on PCI 2833 default n 2834 help 2835 If enabled this option will include drivers and the core 2836 infrastructure code to support RapidIO interconnect devices. 2837 2838source "drivers/rapidio/Kconfig" 2839 2840config X86_SYSFB 2841 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2842 help 2843 Firmwares often provide initial graphics framebuffers so the BIOS, 2844 bootloader or kernel can show basic video-output during boot for 2845 user-guidance and debugging. Historically, x86 used the VESA BIOS 2846 Extensions and EFI-framebuffers for this, which are mostly limited 2847 to x86. 2848 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2849 framebuffers so the new generic system-framebuffer drivers can be 2850 used on x86. If the framebuffer is not compatible with the generic 2851 modes, it is adverticed as fallback platform framebuffer so legacy 2852 drivers like efifb, vesafb and uvesafb can pick it up. 2853 If this option is not selected, all system framebuffers are always 2854 marked as fallback platform framebuffers as usual. 2855 2856 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2857 not be able to pick up generic system framebuffers if this option 2858 is selected. You are highly encouraged to enable simplefb as 2859 replacement if you select this option. simplefb can correctly deal 2860 with generic system framebuffers. But you should still keep vesafb 2861 and others enabled as fallback if a system framebuffer is 2862 incompatible with simplefb. 2863 2864 If unsure, say Y. 2865 2866endmenu 2867 2868 2869menu "Executable file formats / Emulations" 2870 2871source "fs/Kconfig.binfmt" 2872 2873config IA32_EMULATION 2874 bool "IA32 Emulation" 2875 depends on X86_64 2876 select ARCH_WANT_OLD_COMPAT_IPC 2877 select BINFMT_ELF 2878 select COMPAT_BINFMT_ELF 2879 select COMPAT_OLD_SIGACTION 2880 ---help--- 2881 Include code to run legacy 32-bit programs under a 2882 64-bit kernel. You should likely turn this on, unless you're 2883 100% sure that you don't have any 32-bit programs left. 2884 2885config IA32_AOUT 2886 tristate "IA32 a.out support" 2887 depends on IA32_EMULATION 2888 ---help--- 2889 Support old a.out binaries in the 32bit emulation. 2890 2891config X86_X32 2892 bool "x32 ABI for 64-bit mode" 2893 depends on X86_64 2894 ---help--- 2895 Include code to run binaries for the x32 native 32-bit ABI 2896 for 64-bit processors. An x32 process gets access to the 2897 full 64-bit register file and wide data path while leaving 2898 pointers at 32 bits for smaller memory footprint. 2899 2900 You will need a recent binutils (2.22 or later) with 2901 elf32_x86_64 support enabled to compile a kernel with this 2902 option set. 2903 2904config COMPAT_32 2905 def_bool y 2906 depends on IA32_EMULATION || X86_32 2907 select HAVE_UID16 2908 select OLD_SIGSUSPEND3 2909 2910config COMPAT 2911 def_bool y 2912 depends on IA32_EMULATION || X86_X32 2913 2914if COMPAT 2915config COMPAT_FOR_U64_ALIGNMENT 2916 def_bool y 2917 2918config SYSVIPC_COMPAT 2919 def_bool y 2920 depends on SYSVIPC 2921endif 2922 2923endmenu 2924 2925 2926config HAVE_ATOMIC_IOMAP 2927 def_bool y 2928 depends on X86_32 2929 2930config X86_DEV_DMA_OPS 2931 bool 2932 depends on X86_64 || STA2X11 2933 2934config X86_DMA_REMAP 2935 bool 2936 depends on STA2X11 2937 2938config HAVE_GENERIC_GUP 2939 def_bool y 2940 2941source "net/Kconfig" 2942 2943source "drivers/Kconfig" 2944 2945source "drivers/firmware/Kconfig" 2946 2947source "fs/Kconfig" 2948 2949source "arch/x86/Kconfig.debug" 2950 2951source "security/Kconfig" 2952 2953source "crypto/Kconfig" 2954 2955source "arch/x86/kvm/Kconfig" 2956 2957source "lib/Kconfig" 2958