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_DEBUG_STACKOVERFLOW 18 select MODULES_USE_ELF_REL 19 select OLD_SIGACTION 20 21config X86_64 22 def_bool y 23 depends on 64BIT 24 # Options that are inherently 64-bit kernel only: 25 select ARCH_HAS_GIGANTIC_PAGE 26 select ARCH_SUPPORTS_INT128 27 select ARCH_USE_CMPXCHG_LOCKREF 28 select HAVE_ARCH_SOFT_DIRTY 29 select MODULES_USE_ELF_RELA 30 select NEED_DMA_MAP_STATE 31 select SWIOTLB 32 select ARCH_HAS_SYSCALL_WRAPPER 33 34# 35# Arch settings 36# 37# ( Note that options that are marked 'if X86_64' could in principle be 38# ported to 32-bit as well. ) 39# 40config X86 41 def_bool y 42 # 43 # Note: keep this list sorted alphabetically 44 # 45 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 46 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 47 select ARCH_32BIT_OFF_T if X86_32 48 select ARCH_CLOCKSOURCE_DATA 49 select ARCH_CLOCKSOURCE_INIT 50 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 51 select ARCH_HAS_DEBUG_VIRTUAL 52 select ARCH_HAS_DEVMEM_IS_ALLOWED 53 select ARCH_HAS_ELF_RANDOMIZE 54 select ARCH_HAS_FAST_MULTIPLIER 55 select ARCH_HAS_FILTER_PGPROT 56 select ARCH_HAS_FORTIFY_SOURCE 57 select ARCH_HAS_GCOV_PROFILE_ALL 58 select ARCH_HAS_KCOV if X86_64 59 select ARCH_HAS_MEMBARRIER_SYNC_CORE 60 select ARCH_HAS_PMEM_API if X86_64 61 select ARCH_HAS_PTE_SPECIAL 62 select ARCH_HAS_REFCOUNT 63 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 64 select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE 65 select ARCH_HAS_SET_MEMORY 66 select ARCH_HAS_SET_DIRECT_MAP 67 select ARCH_HAS_STRICT_KERNEL_RWX 68 select ARCH_HAS_STRICT_MODULE_RWX 69 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 70 select ARCH_HAS_UBSAN_SANITIZE_ALL 71 select ARCH_HAS_ZONE_DEVICE if X86_64 72 select ARCH_HAVE_NMI_SAFE_CMPXCHG 73 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 74 select ARCH_MIGHT_HAVE_PC_PARPORT 75 select ARCH_MIGHT_HAVE_PC_SERIO 76 select ARCH_STACKWALK 77 select ARCH_SUPPORTS_ACPI 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 EDAC_ATOMIC_SCRUB 92 select EDAC_SUPPORT 93 select GENERIC_CLOCKEVENTS 94 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 95 select GENERIC_CLOCKEVENTS_MIN_ADJUST 96 select GENERIC_CMOS_UPDATE 97 select GENERIC_CPU_AUTOPROBE 98 select GENERIC_CPU_VULNERABILITIES 99 select GENERIC_EARLY_IOREMAP 100 select GENERIC_FIND_FIRST_BIT 101 select GENERIC_IOMAP 102 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 103 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 104 select GENERIC_IRQ_MIGRATION if SMP 105 select GENERIC_IRQ_PROBE 106 select GENERIC_IRQ_RESERVATION_MODE 107 select GENERIC_IRQ_SHOW 108 select GENERIC_PENDING_IRQ if SMP 109 select GENERIC_SMP_IDLE_THREAD 110 select GENERIC_STRNCPY_FROM_USER 111 select GENERIC_STRNLEN_USER 112 select GENERIC_TIME_VSYSCALL 113 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 114 select HAVE_ACPI_APEI if ACPI 115 select HAVE_ACPI_APEI_NMI if ACPI 116 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 117 select HAVE_ARCH_AUDITSYSCALL 118 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 119 select HAVE_ARCH_JUMP_LABEL 120 select HAVE_ARCH_JUMP_LABEL_RELATIVE 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_PREL32_RELOCATIONS 127 select HAVE_ARCH_SECCOMP_FILTER 128 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 129 select HAVE_ARCH_STACKLEAK 130 select HAVE_ARCH_TRACEHOOK 131 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 132 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 133 select HAVE_ARCH_VMAP_STACK if X86_64 134 select HAVE_ARCH_WITHIN_STACK_FRAMES 135 select HAVE_CMPXCHG_DOUBLE 136 select HAVE_CMPXCHG_LOCAL 137 select HAVE_CONTEXT_TRACKING if X86_64 138 select HAVE_COPY_THREAD_TLS 139 select HAVE_C_RECORDMCOUNT 140 select HAVE_DEBUG_KMEMLEAK 141 select HAVE_DMA_CONTIGUOUS 142 select HAVE_DYNAMIC_FTRACE 143 select HAVE_DYNAMIC_FTRACE_WITH_REGS 144 select HAVE_EBPF_JIT 145 select HAVE_EFFICIENT_UNALIGNED_ACCESS 146 select HAVE_EISA 147 select HAVE_EXIT_THREAD 148 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 149 select HAVE_FTRACE_MCOUNT_RECORD 150 select HAVE_FUNCTION_GRAPH_TRACER 151 select HAVE_FUNCTION_TRACER 152 select HAVE_GCC_PLUGINS 153 select HAVE_HW_BREAKPOINT 154 select HAVE_IDE 155 select HAVE_IOREMAP_PROT 156 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 157 select HAVE_IRQ_TIME_ACCOUNTING 158 select HAVE_KERNEL_BZIP2 159 select HAVE_KERNEL_GZIP 160 select HAVE_KERNEL_LZ4 161 select HAVE_KERNEL_LZMA 162 select HAVE_KERNEL_LZO 163 select HAVE_KERNEL_XZ 164 select HAVE_KPROBES 165 select HAVE_KPROBES_ON_FTRACE 166 select HAVE_FUNCTION_ERROR_INJECTION 167 select HAVE_KRETPROBES 168 select HAVE_KVM 169 select HAVE_LIVEPATCH if X86_64 170 select HAVE_MEMBLOCK_NODE_MAP 171 select HAVE_MIXED_BREAKPOINTS_REGS 172 select HAVE_MOD_ARCH_SPECIFIC 173 select HAVE_MOVE_PMD 174 select HAVE_NMI 175 select HAVE_OPROFILE 176 select HAVE_OPTPROBES 177 select HAVE_PCSPKR_PLATFORM 178 select HAVE_PERF_EVENTS 179 select HAVE_PERF_EVENTS_NMI 180 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 181 select HAVE_PCI 182 select HAVE_PERF_REGS 183 select HAVE_PERF_USER_STACK_DUMP 184 select HAVE_RCU_TABLE_FREE if PARAVIRT 185 select HAVE_REGS_AND_STACK_ACCESS_API 186 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 187 select HAVE_FUNCTION_ARG_ACCESS_API 188 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 189 select HAVE_STACK_VALIDATION if X86_64 190 select HAVE_RSEQ 191 select HAVE_SYSCALL_TRACEPOINTS 192 select HAVE_UNSTABLE_SCHED_CLOCK 193 select HAVE_USER_RETURN_NOTIFIER 194 select HOTPLUG_SMT if SMP 195 select IRQ_FORCED_THREADING 196 select NEED_SG_DMA_LENGTH 197 select PCI_DOMAINS if PCI 198 select PCI_LOCKLESS_CONFIG if PCI 199 select PERF_EVENTS 200 select RTC_LIB 201 select RTC_MC146818_LIB 202 select SPARSE_IRQ 203 select SRCU 204 select SYSCTL_EXCEPTION_TRACE 205 select THREAD_INFO_IN_TASK 206 select USER_STACKTRACE_SUPPORT 207 select VIRT_TO_BUS 208 select X86_FEATURE_NAMES if PROC_FS 209 210config INSTRUCTION_DECODER 211 def_bool y 212 depends on KPROBES || PERF_EVENTS || UPROBES 213 214config OUTPUT_FORMAT 215 string 216 default "elf32-i386" if X86_32 217 default "elf64-x86-64" if X86_64 218 219config ARCH_DEFCONFIG 220 string 221 default "arch/x86/configs/i386_defconfig" if X86_32 222 default "arch/x86/configs/x86_64_defconfig" if X86_64 223 224config LOCKDEP_SUPPORT 225 def_bool y 226 227config STACKTRACE_SUPPORT 228 def_bool y 229 230config MMU 231 def_bool y 232 233config ARCH_MMAP_RND_BITS_MIN 234 default 28 if 64BIT 235 default 8 236 237config ARCH_MMAP_RND_BITS_MAX 238 default 32 if 64BIT 239 default 16 240 241config ARCH_MMAP_RND_COMPAT_BITS_MIN 242 default 8 243 244config ARCH_MMAP_RND_COMPAT_BITS_MAX 245 default 16 246 247config SBUS 248 bool 249 250config GENERIC_ISA_DMA 251 def_bool y 252 depends on ISA_DMA_API 253 254config GENERIC_BUG 255 def_bool y 256 depends on BUG 257 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 258 259config GENERIC_BUG_RELATIVE_POINTERS 260 bool 261 262config GENERIC_HWEIGHT 263 def_bool y 264 265config ARCH_MAY_HAVE_PC_FDC 266 def_bool y 267 depends on ISA_DMA_API 268 269config GENERIC_CALIBRATE_DELAY 270 def_bool y 271 272config ARCH_HAS_CPU_RELAX 273 def_bool y 274 275config ARCH_HAS_CACHE_LINE_SIZE 276 def_bool y 277 278config ARCH_HAS_FILTER_PGPROT 279 def_bool y 280 281config HAVE_SETUP_PER_CPU_AREA 282 def_bool y 283 284config NEED_PER_CPU_EMBED_FIRST_CHUNK 285 def_bool y 286 287config NEED_PER_CPU_PAGE_FIRST_CHUNK 288 def_bool y 289 290config ARCH_HIBERNATION_POSSIBLE 291 def_bool y 292 293config ARCH_SUSPEND_POSSIBLE 294 def_bool y 295 296config ARCH_WANT_HUGE_PMD_SHARE 297 def_bool y 298 299config ARCH_WANT_GENERAL_HUGETLB 300 def_bool y 301 302config ZONE_DMA32 303 def_bool y if X86_64 304 305config AUDIT_ARCH 306 def_bool y if X86_64 307 308config ARCH_SUPPORTS_OPTIMIZED_INLINING 309 def_bool y 310 311config ARCH_SUPPORTS_DEBUG_PAGEALLOC 312 def_bool y 313 314config KASAN_SHADOW_OFFSET 315 hex 316 depends on KASAN 317 default 0xdffffc0000000000 318 319config HAVE_INTEL_TXT 320 def_bool y 321 depends on INTEL_IOMMU && ACPI 322 323config X86_32_SMP 324 def_bool y 325 depends on X86_32 && SMP 326 327config X86_64_SMP 328 def_bool y 329 depends on X86_64 && SMP 330 331config X86_32_LAZY_GS 332 def_bool y 333 depends on X86_32 && !STACKPROTECTOR 334 335config ARCH_SUPPORTS_UPROBES 336 def_bool y 337 338config FIX_EARLYCON_MEM 339 def_bool y 340 341config DYNAMIC_PHYSICAL_MASK 342 bool 343 344config PGTABLE_LEVELS 345 int 346 default 5 if X86_5LEVEL 347 default 4 if X86_64 348 default 3 if X86_PAE 349 default 2 350 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 359menu "Processor type and features" 360 361config ZONE_DMA 362 bool "DMA memory allocation support" if EXPERT 363 default y 364 help 365 DMA memory allocation support allows devices with less than 32-bit 366 addressing to allocate within the first 16MB of address space. 367 Disable if no such devices will be used. 368 369 If unsure, say Y. 370 371config SMP 372 bool "Symmetric multi-processing support" 373 ---help--- 374 This enables support for systems with more than one CPU. If you have 375 a system with only one CPU, say N. If you have a system with more 376 than one CPU, say Y. 377 378 If you say N here, the kernel will run on uni- and multiprocessor 379 machines, but will use only one CPU of a multiprocessor machine. If 380 you say Y here, the kernel will run on many, but not all, 381 uniprocessor machines. On a uniprocessor machine, the kernel 382 will run faster if you say N here. 383 384 Note that if you say Y here and choose architecture "586" or 385 "Pentium" under "Processor family", the kernel will not work on 486 386 architectures. Similarly, multiprocessor kernels for the "PPro" 387 architecture may not work on all Pentium based boards. 388 389 People using multiprocessor machines who say Y here should also say 390 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 391 Management" code will be disabled if you say Y here. 392 393 See also <file:Documentation/x86/i386/IO-APIC.txt>, 394 <file:Documentation/lockup-watchdogs.txt> and the SMP-HOWTO available at 395 <http://www.tldp.org/docs.html#howto>. 396 397 If you don't know what to do here, say N. 398 399config X86_FEATURE_NAMES 400 bool "Processor feature human-readable names" if EMBEDDED 401 default y 402 ---help--- 403 This option compiles in a table of x86 feature bits and corresponding 404 names. This is required to support /proc/cpuinfo and a few kernel 405 messages. You can disable this to save space, at the expense of 406 making those few kernel messages show numeric feature bits instead. 407 408 If in doubt, say Y. 409 410config X86_X2APIC 411 bool "Support x2apic" 412 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 413 ---help--- 414 This enables x2apic support on CPUs that have this feature. 415 416 This allows 32-bit apic IDs (so it can support very large systems), 417 and accesses the local apic via MSRs not via mmio. 418 419 If you don't know what to do here, say N. 420 421config X86_MPPARSE 422 bool "Enable MPS table" if ACPI || SFI 423 default y 424 depends on X86_LOCAL_APIC 425 ---help--- 426 For old smp systems that do not have proper acpi support. Newer systems 427 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 428 429config GOLDFISH 430 def_bool y 431 depends on X86_GOLDFISH 432 433config RETPOLINE 434 bool "Avoid speculative indirect branches in kernel" 435 default y 436 select STACK_VALIDATION if HAVE_STACK_VALIDATION 437 help 438 Compile kernel with the retpoline compiler options to guard against 439 kernel-to-user data leaks by avoiding speculative indirect 440 branches. Requires a compiler with -mindirect-branch=thunk-extern 441 support for full protection. The kernel may run slower. 442 443config X86_CPU_RESCTRL 444 bool "x86 CPU resource control support" 445 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 446 select KERNFS 447 help 448 Enable x86 CPU resource control support. 449 450 Provide support for the allocation and monitoring of system resources 451 usage by the CPU. 452 453 Intel calls this Intel Resource Director Technology 454 (Intel(R) RDT). More information about RDT can be found in the 455 Intel x86 Architecture Software Developer Manual. 456 457 AMD calls this AMD Platform Quality of Service (AMD QoS). 458 More information about AMD QoS can be found in the AMD64 Technology 459 Platform Quality of Service Extensions manual. 460 461 Say N if unsure. 462 463if X86_32 464config X86_BIGSMP 465 bool "Support for big SMP systems with more than 8 CPUs" 466 depends on SMP 467 ---help--- 468 This option is needed for the systems that have more than 8 CPUs 469 470config X86_EXTENDED_PLATFORM 471 bool "Support for extended (non-PC) x86 platforms" 472 default y 473 ---help--- 474 If you disable this option then the kernel will only support 475 standard PC platforms. (which covers the vast majority of 476 systems out there.) 477 478 If you enable this option then you'll be able to select support 479 for the following (non-PC) 32 bit x86 platforms: 480 Goldfish (Android emulator) 481 AMD Elan 482 RDC R-321x SoC 483 SGI 320/540 (Visual Workstation) 484 STA2X11-based (e.g. Northville) 485 Moorestown MID devices 486 487 If you have one of these systems, or if you want to build a 488 generic distribution kernel, say Y here - otherwise say N. 489endif 490 491if X86_64 492config X86_EXTENDED_PLATFORM 493 bool "Support for extended (non-PC) x86 platforms" 494 default y 495 ---help--- 496 If you disable this option then the kernel will only support 497 standard PC platforms. (which covers the vast majority of 498 systems out there.) 499 500 If you enable this option then you'll be able to select support 501 for the following (non-PC) 64 bit x86 platforms: 502 Numascale NumaChip 503 ScaleMP vSMP 504 SGI Ultraviolet 505 506 If you have one of these systems, or if you want to build a 507 generic distribution kernel, say Y here - otherwise say N. 508endif 509# This is an alphabetically sorted list of 64 bit extended platforms 510# Please maintain the alphabetic order if and when there are additions 511config X86_NUMACHIP 512 bool "Numascale NumaChip" 513 depends on X86_64 514 depends on X86_EXTENDED_PLATFORM 515 depends on NUMA 516 depends on SMP 517 depends on X86_X2APIC 518 depends on PCI_MMCONFIG 519 ---help--- 520 Adds support for Numascale NumaChip large-SMP systems. Needed to 521 enable more than ~168 cores. 522 If you don't have one of these, you should say N here. 523 524config X86_VSMP 525 bool "ScaleMP vSMP" 526 select HYPERVISOR_GUEST 527 select PARAVIRT 528 depends on X86_64 && PCI 529 depends on X86_EXTENDED_PLATFORM 530 depends on SMP 531 ---help--- 532 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 533 supposed to run on these EM64T-based machines. Only choose this option 534 if you have one of these machines. 535 536config X86_UV 537 bool "SGI Ultraviolet" 538 depends on X86_64 539 depends on X86_EXTENDED_PLATFORM 540 depends on NUMA 541 depends on EFI 542 depends on X86_X2APIC 543 depends on PCI 544 ---help--- 545 This option is needed in order to support SGI Ultraviolet systems. 546 If you don't have one of these, you should say N here. 547 548# Following is an alphabetically sorted list of 32 bit extended platforms 549# Please maintain the alphabetic order if and when there are additions 550 551config X86_GOLDFISH 552 bool "Goldfish (Virtual Platform)" 553 depends on X86_EXTENDED_PLATFORM 554 ---help--- 555 Enable support for the Goldfish virtual platform used primarily 556 for Android development. Unless you are building for the Android 557 Goldfish emulator say N here. 558 559config X86_INTEL_CE 560 bool "CE4100 TV platform" 561 depends on PCI 562 depends on PCI_GODIRECT 563 depends on X86_IO_APIC 564 depends on X86_32 565 depends on X86_EXTENDED_PLATFORM 566 select X86_REBOOTFIXUPS 567 select OF 568 select OF_EARLY_FLATTREE 569 ---help--- 570 Select for the Intel CE media processor (CE4100) SOC. 571 This option compiles in support for the CE4100 SOC for settop 572 boxes and media devices. 573 574config X86_INTEL_MID 575 bool "Intel MID platform support" 576 depends on X86_EXTENDED_PLATFORM 577 depends on X86_PLATFORM_DEVICES 578 depends on PCI 579 depends on X86_64 || (PCI_GOANY && X86_32) 580 depends on X86_IO_APIC 581 select SFI 582 select I2C 583 select DW_APB_TIMER 584 select APB_TIMER 585 select INTEL_SCU_IPC 586 select MFD_INTEL_MSIC 587 ---help--- 588 Select to build a kernel capable of supporting Intel MID (Mobile 589 Internet Device) platform systems which do not have the PCI legacy 590 interfaces. If you are building for a PC class system say N here. 591 592 Intel MID platforms are based on an Intel processor and chipset which 593 consume less power than most of the x86 derivatives. 594 595config X86_INTEL_QUARK 596 bool "Intel Quark platform support" 597 depends on X86_32 598 depends on X86_EXTENDED_PLATFORM 599 depends on X86_PLATFORM_DEVICES 600 depends on X86_TSC 601 depends on PCI 602 depends on PCI_GOANY 603 depends on X86_IO_APIC 604 select IOSF_MBI 605 select INTEL_IMR 606 select COMMON_CLK 607 ---help--- 608 Select to include support for Quark X1000 SoC. 609 Say Y here if you have a Quark based system such as the Arduino 610 compatible Intel Galileo. 611 612config X86_INTEL_LPSS 613 bool "Intel Low Power Subsystem Support" 614 depends on X86 && ACPI && PCI 615 select COMMON_CLK 616 select PINCTRL 617 select IOSF_MBI 618 ---help--- 619 Select to build support for Intel Low Power Subsystem such as 620 found on Intel Lynxpoint PCH. Selecting this option enables 621 things like clock tree (common clock framework) and pincontrol 622 which are needed by the LPSS peripheral drivers. 623 624config X86_AMD_PLATFORM_DEVICE 625 bool "AMD ACPI2Platform devices support" 626 depends on ACPI 627 select COMMON_CLK 628 select PINCTRL 629 ---help--- 630 Select to interpret AMD specific ACPI device to platform device 631 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 632 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 633 implemented under PINCTRL subsystem. 634 635config IOSF_MBI 636 tristate "Intel SoC IOSF Sideband support for SoC platforms" 637 depends on PCI 638 ---help--- 639 This option enables sideband register access support for Intel SoC 640 platforms. On these platforms the IOSF sideband is used in lieu of 641 MSR's for some register accesses, mostly but not limited to thermal 642 and power. Drivers may query the availability of this device to 643 determine if they need the sideband in order to work on these 644 platforms. The sideband is available on the following SoC products. 645 This list is not meant to be exclusive. 646 - BayTrail 647 - Braswell 648 - Quark 649 650 You should say Y if you are running a kernel on one of these SoC's. 651 652config IOSF_MBI_DEBUG 653 bool "Enable IOSF sideband access through debugfs" 654 depends on IOSF_MBI && DEBUG_FS 655 ---help--- 656 Select this option to expose the IOSF sideband access registers (MCR, 657 MDR, MCRX) through debugfs to write and read register information from 658 different units on the SoC. This is most useful for obtaining device 659 state information for debug and analysis. As this is a general access 660 mechanism, users of this option would have specific knowledge of the 661 device they want to access. 662 663 If you don't require the option or are in doubt, say N. 664 665config X86_RDC321X 666 bool "RDC R-321x SoC" 667 depends on X86_32 668 depends on X86_EXTENDED_PLATFORM 669 select M486 670 select X86_REBOOTFIXUPS 671 ---help--- 672 This option is needed for RDC R-321x system-on-chip, also known 673 as R-8610-(G). 674 If you don't have one of these chips, you should say N here. 675 676config X86_32_NON_STANDARD 677 bool "Support non-standard 32-bit SMP architectures" 678 depends on X86_32 && SMP 679 depends on X86_EXTENDED_PLATFORM 680 ---help--- 681 This option compiles in the bigsmp and STA2X11 default 682 subarchitectures. It is intended for a generic binary 683 kernel. If you select them all, kernel will probe it one by 684 one and will fallback to default. 685 686# Alphabetically sorted list of Non standard 32 bit platforms 687 688config X86_SUPPORTS_MEMORY_FAILURE 689 def_bool y 690 # MCE code calls memory_failure(): 691 depends on X86_MCE 692 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 693 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 694 depends on X86_64 || !SPARSEMEM 695 select ARCH_SUPPORTS_MEMORY_FAILURE 696 697config STA2X11 698 bool "STA2X11 Companion Chip Support" 699 depends on X86_32_NON_STANDARD && PCI 700 select ARCH_HAS_PHYS_TO_DMA 701 select SWIOTLB 702 select MFD_STA2X11 703 select GPIOLIB 704 ---help--- 705 This adds support for boards based on the STA2X11 IO-Hub, 706 a.k.a. "ConneXt". The chip is used in place of the standard 707 PC chipset, so all "standard" peripherals are missing. If this 708 option is selected the kernel will still be able to boot on 709 standard PC machines. 710 711config X86_32_IRIS 712 tristate "Eurobraille/Iris poweroff module" 713 depends on X86_32 714 ---help--- 715 The Iris machines from EuroBraille do not have APM or ACPI support 716 to shut themselves down properly. A special I/O sequence is 717 needed to do so, which is what this module does at 718 kernel shutdown. 719 720 This is only for Iris machines from EuroBraille. 721 722 If unused, say N. 723 724config SCHED_OMIT_FRAME_POINTER 725 def_bool y 726 prompt "Single-depth WCHAN output" 727 depends on X86 728 ---help--- 729 Calculate simpler /proc/<PID>/wchan values. If this option 730 is disabled then wchan values will recurse back to the 731 caller function. This provides more accurate wchan values, 732 at the expense of slightly more scheduling overhead. 733 734 If in doubt, say "Y". 735 736menuconfig HYPERVISOR_GUEST 737 bool "Linux guest support" 738 ---help--- 739 Say Y here to enable options for running Linux under various hyper- 740 visors. This option enables basic hypervisor detection and platform 741 setup. 742 743 If you say N, all options in this submenu will be skipped and 744 disabled, and Linux guest support won't be built in. 745 746if HYPERVISOR_GUEST 747 748config PARAVIRT 749 bool "Enable paravirtualization code" 750 ---help--- 751 This changes the kernel so it can modify itself when it is run 752 under a hypervisor, potentially improving performance significantly 753 over full virtualization. However, when run without a hypervisor 754 the kernel is theoretically slower and slightly larger. 755 756config PARAVIRT_XXL 757 bool 758 759config PARAVIRT_DEBUG 760 bool "paravirt-ops debugging" 761 depends on PARAVIRT && DEBUG_KERNEL 762 ---help--- 763 Enable to debug paravirt_ops internals. Specifically, BUG if 764 a paravirt_op is missing when it is called. 765 766config PARAVIRT_SPINLOCKS 767 bool "Paravirtualization layer for spinlocks" 768 depends on PARAVIRT && SMP 769 ---help--- 770 Paravirtualized spinlocks allow a pvops backend to replace the 771 spinlock implementation with something virtualization-friendly 772 (for example, block the virtual CPU rather than spinning). 773 774 It has a minimal impact on native kernels and gives a nice performance 775 benefit on paravirtualized KVM / Xen kernels. 776 777 If you are unsure how to answer this question, answer Y. 778 779source "arch/x86/xen/Kconfig" 780 781config KVM_GUEST 782 bool "KVM Guest support (including kvmclock)" 783 depends on PARAVIRT 784 select PARAVIRT_CLOCK 785 default y 786 ---help--- 787 This option enables various optimizations for running under the KVM 788 hypervisor. It includes a paravirtualized clock, so that instead 789 of relying on a PIT (or probably other) emulation by the 790 underlying device model, the host provides the guest with 791 timing infrastructure such as time of day, and system time 792 793config PVH 794 bool "Support for running PVH guests" 795 ---help--- 796 This option enables the PVH entry point for guest virtual machines 797 as specified in the x86/HVM direct boot ABI. 798 799config KVM_DEBUG_FS 800 bool "Enable debug information for KVM Guests in debugfs" 801 depends on KVM_GUEST && DEBUG_FS 802 ---help--- 803 This option enables collection of various statistics for KVM guest. 804 Statistics are displayed in debugfs filesystem. Enabling this option 805 may incur significant overhead. 806 807config PARAVIRT_TIME_ACCOUNTING 808 bool "Paravirtual steal time accounting" 809 depends on PARAVIRT 810 ---help--- 811 Select this option to enable fine granularity task steal time 812 accounting. Time spent executing other tasks in parallel with 813 the current vCPU is discounted from the vCPU power. To account for 814 that, there can be a small performance impact. 815 816 If in doubt, say N here. 817 818config PARAVIRT_CLOCK 819 bool 820 821config JAILHOUSE_GUEST 822 bool "Jailhouse non-root cell support" 823 depends on X86_64 && PCI 824 select X86_PM_TIMER 825 ---help--- 826 This option allows to run Linux as guest in a Jailhouse non-root 827 cell. You can leave this option disabled if you only want to start 828 Jailhouse and run Linux afterwards in the root cell. 829 830endif #HYPERVISOR_GUEST 831 832source "arch/x86/Kconfig.cpu" 833 834config HPET_TIMER 835 def_bool X86_64 836 prompt "HPET Timer Support" if X86_32 837 ---help--- 838 Use the IA-PC HPET (High Precision Event Timer) to manage 839 time in preference to the PIT and RTC, if a HPET is 840 present. 841 HPET is the next generation timer replacing legacy 8254s. 842 The HPET provides a stable time base on SMP 843 systems, unlike the TSC, but it is more expensive to access, 844 as it is off-chip. The interface used is documented 845 in the HPET spec, revision 1. 846 847 You can safely choose Y here. However, HPET will only be 848 activated if the platform and the BIOS support this feature. 849 Otherwise the 8254 will be used for timing services. 850 851 Choose N to continue using the legacy 8254 timer. 852 853config HPET_EMULATE_RTC 854 def_bool y 855 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 856 857config APB_TIMER 858 def_bool y if X86_INTEL_MID 859 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 860 select DW_APB_TIMER 861 depends on X86_INTEL_MID && SFI 862 help 863 APB timer is the replacement for 8254, HPET on X86 MID platforms. 864 The APBT provides a stable time base on SMP 865 systems, unlike the TSC, but it is more expensive to access, 866 as it is off-chip. APB timers are always running regardless of CPU 867 C states, they are used as per CPU clockevent device when possible. 868 869# Mark as expert because too many people got it wrong. 870# The code disables itself when not needed. 871config DMI 872 default y 873 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 874 bool "Enable DMI scanning" if EXPERT 875 ---help--- 876 Enabled scanning of DMI to identify machine quirks. Say Y 877 here unless you have verified that your setup is not 878 affected by entries in the DMI blacklist. Required by PNP 879 BIOS code. 880 881config GART_IOMMU 882 bool "Old AMD GART IOMMU support" 883 select IOMMU_HELPER 884 select SWIOTLB 885 depends on X86_64 && PCI && AMD_NB 886 ---help--- 887 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 888 GART based hardware IOMMUs. 889 890 The GART supports full DMA access for devices with 32-bit access 891 limitations, on systems with more than 3 GB. This is usually needed 892 for USB, sound, many IDE/SATA chipsets and some other devices. 893 894 Newer systems typically have a modern AMD IOMMU, supported via 895 the CONFIG_AMD_IOMMU=y config option. 896 897 In normal configurations this driver is only active when needed: 898 there's more than 3 GB of memory and the system contains a 899 32-bit limited device. 900 901 If unsure, say Y. 902 903config CALGARY_IOMMU 904 bool "IBM Calgary IOMMU support" 905 select IOMMU_HELPER 906 select SWIOTLB 907 depends on X86_64 && PCI 908 ---help--- 909 Support for hardware IOMMUs in IBM's xSeries x366 and x460 910 systems. Needed to run systems with more than 3GB of memory 911 properly with 32-bit PCI devices that do not support DAC 912 (Double Address Cycle). Calgary also supports bus level 913 isolation, where all DMAs pass through the IOMMU. This 914 prevents them from going anywhere except their intended 915 destination. This catches hard-to-find kernel bugs and 916 mis-behaving drivers and devices that do not use the DMA-API 917 properly to set up their DMA buffers. The IOMMU can be 918 turned off at boot time with the iommu=off parameter. 919 Normally the kernel will make the right choice by itself. 920 If unsure, say Y. 921 922config CALGARY_IOMMU_ENABLED_BY_DEFAULT 923 def_bool y 924 prompt "Should Calgary be enabled by default?" 925 depends on CALGARY_IOMMU 926 ---help--- 927 Should Calgary be enabled by default? if you choose 'y', Calgary 928 will be used (if it exists). If you choose 'n', Calgary will not be 929 used even if it exists. If you choose 'n' and would like to use 930 Calgary anyway, pass 'iommu=calgary' on the kernel command line. 931 If unsure, say Y. 932 933config MAXSMP 934 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 935 depends on X86_64 && SMP && DEBUG_KERNEL 936 select CPUMASK_OFFSTACK 937 ---help--- 938 Enable maximum number of CPUS and NUMA Nodes for this architecture. 939 If unsure, say N. 940 941# 942# The maximum number of CPUs supported: 943# 944# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 945# and which can be configured interactively in the 946# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 947# 948# The ranges are different on 32-bit and 64-bit kernels, depending on 949# hardware capabilities and scalability features of the kernel. 950# 951# ( If MAXSMP is enabled we just use the highest possible value and disable 952# interactive configuration. ) 953# 954 955config NR_CPUS_RANGE_BEGIN 956 int 957 default NR_CPUS_RANGE_END if MAXSMP 958 default 1 if !SMP 959 default 2 960 961config NR_CPUS_RANGE_END 962 int 963 depends on X86_32 964 default 64 if SMP && X86_BIGSMP 965 default 8 if SMP && !X86_BIGSMP 966 default 1 if !SMP 967 968config NR_CPUS_RANGE_END 969 int 970 depends on X86_64 971 default 8192 if SMP && ( MAXSMP || CPUMASK_OFFSTACK) 972 default 512 if SMP && (!MAXSMP && !CPUMASK_OFFSTACK) 973 default 1 if !SMP 974 975config NR_CPUS_DEFAULT 976 int 977 depends on X86_32 978 default 32 if X86_BIGSMP 979 default 8 if SMP 980 default 1 if !SMP 981 982config NR_CPUS_DEFAULT 983 int 984 depends on X86_64 985 default 8192 if MAXSMP 986 default 64 if SMP 987 default 1 if !SMP 988 989config NR_CPUS 990 int "Maximum number of CPUs" if SMP && !MAXSMP 991 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 992 default NR_CPUS_DEFAULT 993 ---help--- 994 This allows you to specify the maximum number of CPUs which this 995 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 996 supported value is 8192, otherwise the maximum value is 512. The 997 minimum value which makes sense is 2. 998 999 This is purely to save memory: each supported CPU adds about 8KB 1000 to the kernel image. 1001 1002config SCHED_SMT 1003 def_bool y if SMP 1004 1005config SCHED_MC 1006 def_bool y 1007 prompt "Multi-core scheduler support" 1008 depends on SMP 1009 ---help--- 1010 Multi-core scheduler support improves the CPU scheduler's decision 1011 making when dealing with multi-core CPU chips at a cost of slightly 1012 increased overhead in some places. If unsure say N here. 1013 1014config SCHED_MC_PRIO 1015 bool "CPU core priorities scheduler support" 1016 depends on SCHED_MC && CPU_SUP_INTEL 1017 select X86_INTEL_PSTATE 1018 select CPU_FREQ 1019 default y 1020 ---help--- 1021 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1022 core ordering determined at manufacturing time, which allows 1023 certain cores to reach higher turbo frequencies (when running 1024 single threaded workloads) than others. 1025 1026 Enabling this kernel feature teaches the scheduler about 1027 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1028 scheduler's CPU selection logic accordingly, so that higher 1029 overall system performance can be achieved. 1030 1031 This feature will have no effect on CPUs without this feature. 1032 1033 If unsure say Y here. 1034 1035config UP_LATE_INIT 1036 def_bool y 1037 depends on !SMP && X86_LOCAL_APIC 1038 1039config X86_UP_APIC 1040 bool "Local APIC support on uniprocessors" if !PCI_MSI 1041 default PCI_MSI 1042 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1043 ---help--- 1044 A local APIC (Advanced Programmable Interrupt Controller) is an 1045 integrated interrupt controller in the CPU. If you have a single-CPU 1046 system which has a processor with a local APIC, you can say Y here to 1047 enable and use it. If you say Y here even though your machine doesn't 1048 have a local APIC, then the kernel will still run with no slowdown at 1049 all. The local APIC supports CPU-generated self-interrupts (timer, 1050 performance counters), and the NMI watchdog which detects hard 1051 lockups. 1052 1053config X86_UP_IOAPIC 1054 bool "IO-APIC support on uniprocessors" 1055 depends on X86_UP_APIC 1056 ---help--- 1057 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1058 SMP-capable replacement for PC-style interrupt controllers. Most 1059 SMP systems and many recent uniprocessor systems have one. 1060 1061 If you have a single-CPU system with an IO-APIC, you can say Y here 1062 to use it. If you say Y here even though your machine doesn't have 1063 an IO-APIC, then the kernel will still run with no slowdown at all. 1064 1065config X86_LOCAL_APIC 1066 def_bool y 1067 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1068 select IRQ_DOMAIN_HIERARCHY 1069 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1070 1071config X86_IO_APIC 1072 def_bool y 1073 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1074 1075config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1076 bool "Reroute for broken boot IRQs" 1077 depends on X86_IO_APIC 1078 ---help--- 1079 This option enables a workaround that fixes a source of 1080 spurious interrupts. This is recommended when threaded 1081 interrupt handling is used on systems where the generation of 1082 superfluous "boot interrupts" cannot be disabled. 1083 1084 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1085 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1086 kernel does during interrupt handling). On chipsets where this 1087 boot IRQ generation cannot be disabled, this workaround keeps 1088 the original IRQ line masked so that only the equivalent "boot 1089 IRQ" is delivered to the CPUs. The workaround also tells the 1090 kernel to set up the IRQ handler on the boot IRQ line. In this 1091 way only one interrupt is delivered to the kernel. Otherwise 1092 the spurious second interrupt may cause the kernel to bring 1093 down (vital) interrupt lines. 1094 1095 Only affects "broken" chipsets. Interrupt sharing may be 1096 increased on these systems. 1097 1098config X86_MCE 1099 bool "Machine Check / overheating reporting" 1100 select GENERIC_ALLOCATOR 1101 default y 1102 ---help--- 1103 Machine Check support allows the processor to notify the 1104 kernel if it detects a problem (e.g. overheating, data corruption). 1105 The action the kernel takes depends on the severity of the problem, 1106 ranging from warning messages to halting the machine. 1107 1108config X86_MCELOG_LEGACY 1109 bool "Support for deprecated /dev/mcelog character device" 1110 depends on X86_MCE 1111 ---help--- 1112 Enable support for /dev/mcelog which is needed by the old mcelog 1113 userspace logging daemon. Consider switching to the new generation 1114 rasdaemon solution. 1115 1116config X86_MCE_INTEL 1117 def_bool y 1118 prompt "Intel MCE features" 1119 depends on X86_MCE && X86_LOCAL_APIC 1120 ---help--- 1121 Additional support for intel specific MCE features such as 1122 the thermal monitor. 1123 1124config X86_MCE_AMD 1125 def_bool y 1126 prompt "AMD MCE features" 1127 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1128 ---help--- 1129 Additional support for AMD specific MCE features such as 1130 the DRAM Error Threshold. 1131 1132config X86_ANCIENT_MCE 1133 bool "Support for old Pentium 5 / WinChip machine checks" 1134 depends on X86_32 && X86_MCE 1135 ---help--- 1136 Include support for machine check handling on old Pentium 5 or WinChip 1137 systems. These typically need to be enabled explicitly on the command 1138 line. 1139 1140config X86_MCE_THRESHOLD 1141 depends on X86_MCE_AMD || X86_MCE_INTEL 1142 def_bool y 1143 1144config X86_MCE_INJECT 1145 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1146 tristate "Machine check injector support" 1147 ---help--- 1148 Provide support for injecting machine checks for testing purposes. 1149 If you don't know what a machine check is and you don't do kernel 1150 QA it is safe to say n. 1151 1152config X86_THERMAL_VECTOR 1153 def_bool y 1154 depends on X86_MCE_INTEL 1155 1156source "arch/x86/events/Kconfig" 1157 1158config X86_LEGACY_VM86 1159 bool "Legacy VM86 support" 1160 depends on X86_32 1161 ---help--- 1162 This option allows user programs to put the CPU into V8086 1163 mode, which is an 80286-era approximation of 16-bit real mode. 1164 1165 Some very old versions of X and/or vbetool require this option 1166 for user mode setting. Similarly, DOSEMU will use it if 1167 available to accelerate real mode DOS programs. However, any 1168 recent version of DOSEMU, X, or vbetool should be fully 1169 functional even without kernel VM86 support, as they will all 1170 fall back to software emulation. Nevertheless, if you are using 1171 a 16-bit DOS program where 16-bit performance matters, vm86 1172 mode might be faster than emulation and you might want to 1173 enable this option. 1174 1175 Note that any app that works on a 64-bit kernel is unlikely to 1176 need this option, as 64-bit kernels don't, and can't, support 1177 V8086 mode. This option is also unrelated to 16-bit protected 1178 mode and is not needed to run most 16-bit programs under Wine. 1179 1180 Enabling this option increases the complexity of the kernel 1181 and slows down exception handling a tiny bit. 1182 1183 If unsure, say N here. 1184 1185config VM86 1186 bool 1187 default X86_LEGACY_VM86 1188 1189config X86_16BIT 1190 bool "Enable support for 16-bit segments" if EXPERT 1191 default y 1192 depends on MODIFY_LDT_SYSCALL 1193 ---help--- 1194 This option is required by programs like Wine to run 16-bit 1195 protected mode legacy code on x86 processors. Disabling 1196 this option saves about 300 bytes on i386, or around 6K text 1197 plus 16K runtime memory on x86-64, 1198 1199config X86_ESPFIX32 1200 def_bool y 1201 depends on X86_16BIT && X86_32 1202 1203config X86_ESPFIX64 1204 def_bool y 1205 depends on X86_16BIT && X86_64 1206 1207config X86_VSYSCALL_EMULATION 1208 bool "Enable vsyscall emulation" if EXPERT 1209 default y 1210 depends on X86_64 1211 ---help--- 1212 This enables emulation of the legacy vsyscall page. Disabling 1213 it is roughly equivalent to booting with vsyscall=none, except 1214 that it will also disable the helpful warning if a program 1215 tries to use a vsyscall. With this option set to N, offending 1216 programs will just segfault, citing addresses of the form 1217 0xffffffffff600?00. 1218 1219 This option is required by many programs built before 2013, and 1220 care should be used even with newer programs if set to N. 1221 1222 Disabling this option saves about 7K of kernel size and 1223 possibly 4K of additional runtime pagetable memory. 1224 1225config TOSHIBA 1226 tristate "Toshiba Laptop support" 1227 depends on X86_32 1228 ---help--- 1229 This adds a driver to safely access the System Management Mode of 1230 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1231 not work on models with a Phoenix BIOS. The System Management Mode 1232 is used to set the BIOS and power saving options on Toshiba portables. 1233 1234 For information on utilities to make use of this driver see the 1235 Toshiba Linux utilities web site at: 1236 <http://www.buzzard.org.uk/toshiba/>. 1237 1238 Say Y if you intend to run this kernel on a Toshiba portable. 1239 Say N otherwise. 1240 1241config I8K 1242 tristate "Dell i8k legacy laptop support" 1243 select HWMON 1244 select SENSORS_DELL_SMM 1245 ---help--- 1246 This option enables legacy /proc/i8k userspace interface in hwmon 1247 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1248 temperature and allows controlling fan speeds of Dell laptops via 1249 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1250 it reports also power and hotkey status. For fan speed control is 1251 needed userspace package i8kutils. 1252 1253 Say Y if you intend to run this kernel on old Dell laptops or want to 1254 use userspace package i8kutils. 1255 Say N otherwise. 1256 1257config X86_REBOOTFIXUPS 1258 bool "Enable X86 board specific fixups for reboot" 1259 depends on X86_32 1260 ---help--- 1261 This enables chipset and/or board specific fixups to be done 1262 in order to get reboot to work correctly. This is only needed on 1263 some combinations of hardware and BIOS. The symptom, for which 1264 this config is intended, is when reboot ends with a stalled/hung 1265 system. 1266 1267 Currently, the only fixup is for the Geode machines using 1268 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1269 1270 Say Y if you want to enable the fixup. Currently, it's safe to 1271 enable this option even if you don't need it. 1272 Say N otherwise. 1273 1274config MICROCODE 1275 bool "CPU microcode loading support" 1276 default y 1277 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1278 select FW_LOADER 1279 ---help--- 1280 If you say Y here, you will be able to update the microcode on 1281 Intel and AMD processors. The Intel support is for the IA32 family, 1282 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1283 AMD support is for families 0x10 and later. You will obviously need 1284 the actual microcode binary data itself which is not shipped with 1285 the Linux kernel. 1286 1287 The preferred method to load microcode from a detached initrd is described 1288 in Documentation/x86/microcode.txt. For that you need to enable 1289 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1290 initrd for microcode blobs. 1291 1292 In addition, you can build the microcode into the kernel. For that you 1293 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1294 config option. 1295 1296config MICROCODE_INTEL 1297 bool "Intel microcode loading support" 1298 depends on MICROCODE 1299 default MICROCODE 1300 select FW_LOADER 1301 ---help--- 1302 This options enables microcode patch loading support for Intel 1303 processors. 1304 1305 For the current Intel microcode data package go to 1306 <https://downloadcenter.intel.com> and search for 1307 'Linux Processor Microcode Data File'. 1308 1309config MICROCODE_AMD 1310 bool "AMD microcode loading support" 1311 depends on MICROCODE 1312 select FW_LOADER 1313 ---help--- 1314 If you select this option, microcode patch loading support for AMD 1315 processors will be enabled. 1316 1317config MICROCODE_OLD_INTERFACE 1318 bool "Ancient loading interface (DEPRECATED)" 1319 default n 1320 depends on MICROCODE 1321 ---help--- 1322 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1323 which was used by userspace tools like iucode_tool and microcode.ctl. 1324 It is inadequate because it runs too late to be able to properly 1325 load microcode on a machine and it needs special tools. Instead, you 1326 should've switched to the early loading method with the initrd or 1327 builtin microcode by now: Documentation/x86/microcode.txt 1328 1329config X86_MSR 1330 tristate "/dev/cpu/*/msr - Model-specific register support" 1331 ---help--- 1332 This device gives privileged processes access to the x86 1333 Model-Specific Registers (MSRs). It is a character device with 1334 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1335 MSR accesses are directed to a specific CPU on multi-processor 1336 systems. 1337 1338config X86_CPUID 1339 tristate "/dev/cpu/*/cpuid - CPU information support" 1340 ---help--- 1341 This device gives processes access to the x86 CPUID instruction to 1342 be executed on a specific processor. It is a character device 1343 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1344 /dev/cpu/31/cpuid. 1345 1346choice 1347 prompt "High Memory Support" 1348 default HIGHMEM4G 1349 depends on X86_32 1350 1351config NOHIGHMEM 1352 bool "off" 1353 ---help--- 1354 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1355 However, the address space of 32-bit x86 processors is only 4 1356 Gigabytes large. That means that, if you have a large amount of 1357 physical memory, not all of it can be "permanently mapped" by the 1358 kernel. The physical memory that's not permanently mapped is called 1359 "high memory". 1360 1361 If you are compiling a kernel which will never run on a machine with 1362 more than 1 Gigabyte total physical RAM, answer "off" here (default 1363 choice and suitable for most users). This will result in a "3GB/1GB" 1364 split: 3GB are mapped so that each process sees a 3GB virtual memory 1365 space and the remaining part of the 4GB virtual memory space is used 1366 by the kernel to permanently map as much physical memory as 1367 possible. 1368 1369 If the machine has between 1 and 4 Gigabytes physical RAM, then 1370 answer "4GB" here. 1371 1372 If more than 4 Gigabytes is used then answer "64GB" here. This 1373 selection turns Intel PAE (Physical Address Extension) mode on. 1374 PAE implements 3-level paging on IA32 processors. PAE is fully 1375 supported by Linux, PAE mode is implemented on all recent Intel 1376 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1377 then the kernel will not boot on CPUs that don't support PAE! 1378 1379 The actual amount of total physical memory will either be 1380 auto detected or can be forced by using a kernel command line option 1381 such as "mem=256M". (Try "man bootparam" or see the documentation of 1382 your boot loader (lilo or loadlin) about how to pass options to the 1383 kernel at boot time.) 1384 1385 If unsure, say "off". 1386 1387config HIGHMEM4G 1388 bool "4GB" 1389 ---help--- 1390 Select this if you have a 32-bit processor and between 1 and 4 1391 gigabytes of physical RAM. 1392 1393config HIGHMEM64G 1394 bool "64GB" 1395 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1396 select X86_PAE 1397 ---help--- 1398 Select this if you have a 32-bit processor and more than 4 1399 gigabytes of physical RAM. 1400 1401endchoice 1402 1403choice 1404 prompt "Memory split" if EXPERT 1405 default VMSPLIT_3G 1406 depends on X86_32 1407 ---help--- 1408 Select the desired split between kernel and user memory. 1409 1410 If the address range available to the kernel is less than the 1411 physical memory installed, the remaining memory will be available 1412 as "high memory". Accessing high memory is a little more costly 1413 than low memory, as it needs to be mapped into the kernel first. 1414 Note that increasing the kernel address space limits the range 1415 available to user programs, making the address space there 1416 tighter. Selecting anything other than the default 3G/1G split 1417 will also likely make your kernel incompatible with binary-only 1418 kernel modules. 1419 1420 If you are not absolutely sure what you are doing, leave this 1421 option alone! 1422 1423 config VMSPLIT_3G 1424 bool "3G/1G user/kernel split" 1425 config VMSPLIT_3G_OPT 1426 depends on !X86_PAE 1427 bool "3G/1G user/kernel split (for full 1G low memory)" 1428 config VMSPLIT_2G 1429 bool "2G/2G user/kernel split" 1430 config VMSPLIT_2G_OPT 1431 depends on !X86_PAE 1432 bool "2G/2G user/kernel split (for full 2G low memory)" 1433 config VMSPLIT_1G 1434 bool "1G/3G user/kernel split" 1435endchoice 1436 1437config PAGE_OFFSET 1438 hex 1439 default 0xB0000000 if VMSPLIT_3G_OPT 1440 default 0x80000000 if VMSPLIT_2G 1441 default 0x78000000 if VMSPLIT_2G_OPT 1442 default 0x40000000 if VMSPLIT_1G 1443 default 0xC0000000 1444 depends on X86_32 1445 1446config HIGHMEM 1447 def_bool y 1448 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1449 1450config X86_PAE 1451 bool "PAE (Physical Address Extension) Support" 1452 depends on X86_32 && !HIGHMEM4G 1453 select PHYS_ADDR_T_64BIT 1454 select SWIOTLB 1455 ---help--- 1456 PAE is required for NX support, and furthermore enables 1457 larger swapspace support for non-overcommit purposes. It 1458 has the cost of more pagetable lookup overhead, and also 1459 consumes more pagetable space per process. 1460 1461config X86_5LEVEL 1462 bool "Enable 5-level page tables support" 1463 select DYNAMIC_MEMORY_LAYOUT 1464 select SPARSEMEM_VMEMMAP 1465 depends on X86_64 1466 ---help--- 1467 5-level paging enables access to larger address space: 1468 upto 128 PiB of virtual address space and 4 PiB of 1469 physical address space. 1470 1471 It will be supported by future Intel CPUs. 1472 1473 A kernel with the option enabled can be booted on machines that 1474 support 4- or 5-level paging. 1475 1476 See Documentation/x86/x86_64/5level-paging.txt for more 1477 information. 1478 1479 Say N if unsure. 1480 1481config X86_DIRECT_GBPAGES 1482 def_bool y 1483 depends on X86_64 && !DEBUG_PAGEALLOC 1484 ---help--- 1485 Certain kernel features effectively disable kernel 1486 linear 1 GB mappings (even if the CPU otherwise 1487 supports them), so don't confuse the user by printing 1488 that we have them enabled. 1489 1490config X86_CPA_STATISTICS 1491 bool "Enable statistic for Change Page Attribute" 1492 depends on DEBUG_FS 1493 ---help--- 1494 Expose statistics about the Change Page Attribute mechanims, which 1495 helps to determine the effectiveness of preserving large and huge 1496 page mappings when mapping protections are changed. 1497 1498config ARCH_HAS_MEM_ENCRYPT 1499 def_bool y 1500 1501config AMD_MEM_ENCRYPT 1502 bool "AMD Secure Memory Encryption (SME) support" 1503 depends on X86_64 && CPU_SUP_AMD 1504 select DYNAMIC_PHYSICAL_MASK 1505 select ARCH_USE_MEMREMAP_PROT 1506 ---help--- 1507 Say yes to enable support for the encryption of system memory. 1508 This requires an AMD processor that supports Secure Memory 1509 Encryption (SME). 1510 1511config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1512 bool "Activate AMD Secure Memory Encryption (SME) by default" 1513 default y 1514 depends on AMD_MEM_ENCRYPT 1515 ---help--- 1516 Say yes to have system memory encrypted by default if running on 1517 an AMD processor that supports Secure Memory Encryption (SME). 1518 1519 If set to Y, then the encryption of system memory can be 1520 deactivated with the mem_encrypt=off command line option. 1521 1522 If set to N, then the encryption of system memory can be 1523 activated with the mem_encrypt=on command line option. 1524 1525# Common NUMA Features 1526config NUMA 1527 bool "Numa Memory Allocation and Scheduler Support" 1528 depends on SMP 1529 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1530 default y if X86_BIGSMP 1531 ---help--- 1532 Enable NUMA (Non Uniform Memory Access) support. 1533 1534 The kernel will try to allocate memory used by a CPU on the 1535 local memory controller of the CPU and add some more 1536 NUMA awareness to the kernel. 1537 1538 For 64-bit this is recommended if the system is Intel Core i7 1539 (or later), AMD Opteron, or EM64T NUMA. 1540 1541 For 32-bit this is only needed if you boot a 32-bit 1542 kernel on a 64-bit NUMA platform. 1543 1544 Otherwise, you should say N. 1545 1546config AMD_NUMA 1547 def_bool y 1548 prompt "Old style AMD Opteron NUMA detection" 1549 depends on X86_64 && NUMA && PCI 1550 ---help--- 1551 Enable AMD NUMA node topology detection. You should say Y here if 1552 you have a multi processor AMD system. This uses an old method to 1553 read the NUMA configuration directly from the builtin Northbridge 1554 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1555 which also takes priority if both are compiled in. 1556 1557config X86_64_ACPI_NUMA 1558 def_bool y 1559 prompt "ACPI NUMA detection" 1560 depends on X86_64 && NUMA && ACPI && PCI 1561 select ACPI_NUMA 1562 ---help--- 1563 Enable ACPI SRAT based node topology detection. 1564 1565# Some NUMA nodes have memory ranges that span 1566# other nodes. Even though a pfn is valid and 1567# between a node's start and end pfns, it may not 1568# reside on that node. See memmap_init_zone() 1569# for details. 1570config NODES_SPAN_OTHER_NODES 1571 def_bool y 1572 depends on X86_64_ACPI_NUMA 1573 1574config NUMA_EMU 1575 bool "NUMA emulation" 1576 depends on NUMA 1577 ---help--- 1578 Enable NUMA emulation. A flat machine will be split 1579 into virtual nodes when booted with "numa=fake=N", where N is the 1580 number of nodes. This is only useful for debugging. 1581 1582config NODES_SHIFT 1583 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1584 range 1 10 1585 default "10" if MAXSMP 1586 default "6" if X86_64 1587 default "3" 1588 depends on NEED_MULTIPLE_NODES 1589 ---help--- 1590 Specify the maximum number of NUMA Nodes available on the target 1591 system. Increases memory reserved to accommodate various tables. 1592 1593config ARCH_HAVE_MEMORY_PRESENT 1594 def_bool y 1595 depends on X86_32 && DISCONTIGMEM 1596 1597config ARCH_FLATMEM_ENABLE 1598 def_bool y 1599 depends on X86_32 && !NUMA 1600 1601config ARCH_DISCONTIGMEM_ENABLE 1602 def_bool n 1603 depends on NUMA && X86_32 1604 depends on BROKEN 1605 1606config ARCH_SPARSEMEM_ENABLE 1607 def_bool y 1608 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1609 select SPARSEMEM_STATIC if X86_32 1610 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1611 1612config ARCH_SPARSEMEM_DEFAULT 1613 def_bool X86_64 || (NUMA && X86_32) 1614 1615config ARCH_SELECT_MEMORY_MODEL 1616 def_bool y 1617 depends on ARCH_SPARSEMEM_ENABLE 1618 1619config ARCH_MEMORY_PROBE 1620 bool "Enable sysfs memory/probe interface" 1621 depends on X86_64 && MEMORY_HOTPLUG 1622 help 1623 This option enables a sysfs memory/probe interface for testing. 1624 See Documentation/memory-hotplug.txt for more information. 1625 If you are unsure how to answer this question, answer N. 1626 1627config ARCH_PROC_KCORE_TEXT 1628 def_bool y 1629 depends on X86_64 && PROC_KCORE 1630 1631config ILLEGAL_POINTER_VALUE 1632 hex 1633 default 0 if X86_32 1634 default 0xdead000000000000 if X86_64 1635 1636config X86_PMEM_LEGACY_DEVICE 1637 bool 1638 1639config X86_PMEM_LEGACY 1640 tristate "Support non-standard NVDIMMs and ADR protected memory" 1641 depends on PHYS_ADDR_T_64BIT 1642 depends on BLK_DEV 1643 select X86_PMEM_LEGACY_DEVICE 1644 select LIBNVDIMM 1645 help 1646 Treat memory marked using the non-standard e820 type of 12 as used 1647 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1648 The kernel will offer these regions to the 'pmem' driver so 1649 they can be used for persistent storage. 1650 1651 Say Y if unsure. 1652 1653config HIGHPTE 1654 bool "Allocate 3rd-level pagetables from highmem" 1655 depends on HIGHMEM 1656 ---help--- 1657 The VM uses one page table entry for each page of physical memory. 1658 For systems with a lot of RAM, this can be wasteful of precious 1659 low memory. Setting this option will put user-space page table 1660 entries in high memory. 1661 1662config X86_CHECK_BIOS_CORRUPTION 1663 bool "Check for low memory corruption" 1664 ---help--- 1665 Periodically check for memory corruption in low memory, which 1666 is suspected to be caused by BIOS. Even when enabled in the 1667 configuration, it is disabled at runtime. Enable it by 1668 setting "memory_corruption_check=1" on the kernel command 1669 line. By default it scans the low 64k of memory every 60 1670 seconds; see the memory_corruption_check_size and 1671 memory_corruption_check_period parameters in 1672 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1673 1674 When enabled with the default parameters, this option has 1675 almost no overhead, as it reserves a relatively small amount 1676 of memory and scans it infrequently. It both detects corruption 1677 and prevents it from affecting the running system. 1678 1679 It is, however, intended as a diagnostic tool; if repeatable 1680 BIOS-originated corruption always affects the same memory, 1681 you can use memmap= to prevent the kernel from using that 1682 memory. 1683 1684config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1685 bool "Set the default setting of memory_corruption_check" 1686 depends on X86_CHECK_BIOS_CORRUPTION 1687 default y 1688 ---help--- 1689 Set whether the default state of memory_corruption_check is 1690 on or off. 1691 1692config X86_RESERVE_LOW 1693 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1694 default 64 1695 range 4 640 1696 ---help--- 1697 Specify the amount of low memory to reserve for the BIOS. 1698 1699 The first page contains BIOS data structures that the kernel 1700 must not use, so that page must always be reserved. 1701 1702 By default we reserve the first 64K of physical RAM, as a 1703 number of BIOSes are known to corrupt that memory range 1704 during events such as suspend/resume or monitor cable 1705 insertion, so it must not be used by the kernel. 1706 1707 You can set this to 4 if you are absolutely sure that you 1708 trust the BIOS to get all its memory reservations and usages 1709 right. If you know your BIOS have problems beyond the 1710 default 64K area, you can set this to 640 to avoid using the 1711 entire low memory range. 1712 1713 If you have doubts about the BIOS (e.g. suspend/resume does 1714 not work or there's kernel crashes after certain hardware 1715 hotplug events) then you might want to enable 1716 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1717 typical corruption patterns. 1718 1719 Leave this to the default value of 64 if you are unsure. 1720 1721config MATH_EMULATION 1722 bool 1723 depends on MODIFY_LDT_SYSCALL 1724 prompt "Math emulation" if X86_32 1725 ---help--- 1726 Linux can emulate a math coprocessor (used for floating point 1727 operations) if you don't have one. 486DX and Pentium processors have 1728 a math coprocessor built in, 486SX and 386 do not, unless you added 1729 a 487DX or 387, respectively. (The messages during boot time can 1730 give you some hints here ["man dmesg"].) Everyone needs either a 1731 coprocessor or this emulation. 1732 1733 If you don't have a math coprocessor, you need to say Y here; if you 1734 say Y here even though you have a coprocessor, the coprocessor will 1735 be used nevertheless. (This behavior can be changed with the kernel 1736 command line option "no387", which comes handy if your coprocessor 1737 is broken. Try "man bootparam" or see the documentation of your boot 1738 loader (lilo or loadlin) about how to pass options to the kernel at 1739 boot time.) This means that it is a good idea to say Y here if you 1740 intend to use this kernel on different machines. 1741 1742 More information about the internals of the Linux math coprocessor 1743 emulation can be found in <file:arch/x86/math-emu/README>. 1744 1745 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1746 kernel, it won't hurt. 1747 1748config MTRR 1749 def_bool y 1750 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1751 ---help--- 1752 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1753 the Memory Type Range Registers (MTRRs) may be used to control 1754 processor access to memory ranges. This is most useful if you have 1755 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1756 allows bus write transfers to be combined into a larger transfer 1757 before bursting over the PCI/AGP bus. This can increase performance 1758 of image write operations 2.5 times or more. Saying Y here creates a 1759 /proc/mtrr file which may be used to manipulate your processor's 1760 MTRRs. Typically the X server should use this. 1761 1762 This code has a reasonably generic interface so that similar 1763 control registers on other processors can be easily supported 1764 as well: 1765 1766 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1767 Registers (ARRs) which provide a similar functionality to MTRRs. For 1768 these, the ARRs are used to emulate the MTRRs. 1769 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1770 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1771 write-combining. All of these processors are supported by this code 1772 and it makes sense to say Y here if you have one of them. 1773 1774 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1775 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1776 can lead to all sorts of problems, so it's good to say Y here. 1777 1778 You can safely say Y even if your machine doesn't have MTRRs, you'll 1779 just add about 9 KB to your kernel. 1780 1781 See <file:Documentation/x86/mtrr.txt> for more information. 1782 1783config MTRR_SANITIZER 1784 def_bool y 1785 prompt "MTRR cleanup support" 1786 depends on MTRR 1787 ---help--- 1788 Convert MTRR layout from continuous to discrete, so X drivers can 1789 add writeback entries. 1790 1791 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1792 The largest mtrr entry size for a continuous block can be set with 1793 mtrr_chunk_size. 1794 1795 If unsure, say Y. 1796 1797config MTRR_SANITIZER_ENABLE_DEFAULT 1798 int "MTRR cleanup enable value (0-1)" 1799 range 0 1 1800 default "0" 1801 depends on MTRR_SANITIZER 1802 ---help--- 1803 Enable mtrr cleanup default value 1804 1805config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1806 int "MTRR cleanup spare reg num (0-7)" 1807 range 0 7 1808 default "1" 1809 depends on MTRR_SANITIZER 1810 ---help--- 1811 mtrr cleanup spare entries default, it can be changed via 1812 mtrr_spare_reg_nr=N on the kernel command line. 1813 1814config X86_PAT 1815 def_bool y 1816 prompt "x86 PAT support" if EXPERT 1817 depends on MTRR 1818 ---help--- 1819 Use PAT attributes to setup page level cache control. 1820 1821 PATs are the modern equivalents of MTRRs and are much more 1822 flexible than MTRRs. 1823 1824 Say N here if you see bootup problems (boot crash, boot hang, 1825 spontaneous reboots) or a non-working video driver. 1826 1827 If unsure, say Y. 1828 1829config ARCH_USES_PG_UNCACHED 1830 def_bool y 1831 depends on X86_PAT 1832 1833config ARCH_RANDOM 1834 def_bool y 1835 prompt "x86 architectural random number generator" if EXPERT 1836 ---help--- 1837 Enable the x86 architectural RDRAND instruction 1838 (Intel Bull Mountain technology) to generate random numbers. 1839 If supported, this is a high bandwidth, cryptographically 1840 secure hardware random number generator. 1841 1842config X86_SMAP 1843 def_bool y 1844 prompt "Supervisor Mode Access Prevention" if EXPERT 1845 ---help--- 1846 Supervisor Mode Access Prevention (SMAP) is a security 1847 feature in newer Intel processors. There is a small 1848 performance cost if this enabled and turned on; there is 1849 also a small increase in the kernel size if this is enabled. 1850 1851 If unsure, say Y. 1852 1853config X86_INTEL_UMIP 1854 def_bool y 1855 depends on CPU_SUP_INTEL 1856 prompt "Intel User Mode Instruction Prevention" if EXPERT 1857 ---help--- 1858 The User Mode Instruction Prevention (UMIP) is a security 1859 feature in newer Intel processors. If enabled, a general 1860 protection fault is issued if the SGDT, SLDT, SIDT, SMSW 1861 or STR instructions are executed in user mode. These instructions 1862 unnecessarily expose information about the hardware state. 1863 1864 The vast majority of applications do not use these instructions. 1865 For the very few that do, software emulation is provided in 1866 specific cases in protected and virtual-8086 modes. Emulated 1867 results are dummy. 1868 1869config X86_INTEL_MPX 1870 prompt "Intel MPX (Memory Protection Extensions)" 1871 def_bool n 1872 # Note: only available in 64-bit mode due to VMA flags shortage 1873 depends on CPU_SUP_INTEL && X86_64 1874 select ARCH_USES_HIGH_VMA_FLAGS 1875 ---help--- 1876 MPX provides hardware features that can be used in 1877 conjunction with compiler-instrumented code to check 1878 memory references. It is designed to detect buffer 1879 overflow or underflow bugs. 1880 1881 This option enables running applications which are 1882 instrumented or otherwise use MPX. It does not use MPX 1883 itself inside the kernel or to protect the kernel 1884 against bad memory references. 1885 1886 Enabling this option will make the kernel larger: 1887 ~8k of kernel text and 36 bytes of data on a 64-bit 1888 defconfig. It adds a long to the 'mm_struct' which 1889 will increase the kernel memory overhead of each 1890 process and adds some branches to paths used during 1891 exec() and munmap(). 1892 1893 For details, see Documentation/x86/intel_mpx.txt 1894 1895 If unsure, say N. 1896 1897config X86_INTEL_MEMORY_PROTECTION_KEYS 1898 prompt "Intel Memory Protection Keys" 1899 def_bool y 1900 # Note: only available in 64-bit mode 1901 depends on CPU_SUP_INTEL && X86_64 1902 select ARCH_USES_HIGH_VMA_FLAGS 1903 select ARCH_HAS_PKEYS 1904 ---help--- 1905 Memory Protection Keys provides a mechanism for enforcing 1906 page-based protections, but without requiring modification of the 1907 page tables when an application changes protection domains. 1908 1909 For details, see Documentation/x86/protection-keys.txt 1910 1911 If unsure, say y. 1912 1913config EFI 1914 bool "EFI runtime service support" 1915 depends on ACPI 1916 select UCS2_STRING 1917 select EFI_RUNTIME_WRAPPERS 1918 ---help--- 1919 This enables the kernel to use EFI runtime services that are 1920 available (such as the EFI variable services). 1921 1922 This option is only useful on systems that have EFI firmware. 1923 In addition, you should use the latest ELILO loader available 1924 at <http://elilo.sourceforge.net> in order to take advantage 1925 of EFI runtime services. However, even with this option, the 1926 resultant kernel should continue to boot on existing non-EFI 1927 platforms. 1928 1929config EFI_STUB 1930 bool "EFI stub support" 1931 depends on EFI && !X86_USE_3DNOW 1932 select RELOCATABLE 1933 ---help--- 1934 This kernel feature allows a bzImage to be loaded directly 1935 by EFI firmware without the use of a bootloader. 1936 1937 See Documentation/efi-stub.txt for more information. 1938 1939config EFI_MIXED 1940 bool "EFI mixed-mode support" 1941 depends on EFI_STUB && X86_64 1942 ---help--- 1943 Enabling this feature allows a 64-bit kernel to be booted 1944 on a 32-bit firmware, provided that your CPU supports 64-bit 1945 mode. 1946 1947 Note that it is not possible to boot a mixed-mode enabled 1948 kernel via the EFI boot stub - a bootloader that supports 1949 the EFI handover protocol must be used. 1950 1951 If unsure, say N. 1952 1953config SECCOMP 1954 def_bool y 1955 prompt "Enable seccomp to safely compute untrusted bytecode" 1956 ---help--- 1957 This kernel feature is useful for number crunching applications 1958 that may need to compute untrusted bytecode during their 1959 execution. By using pipes or other transports made available to 1960 the process as file descriptors supporting the read/write 1961 syscalls, it's possible to isolate those applications in 1962 their own address space using seccomp. Once seccomp is 1963 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 1964 and the task is only allowed to execute a few safe syscalls 1965 defined by each seccomp mode. 1966 1967 If unsure, say Y. Only embedded should say N here. 1968 1969source "kernel/Kconfig.hz" 1970 1971config KEXEC 1972 bool "kexec system call" 1973 select KEXEC_CORE 1974 ---help--- 1975 kexec is a system call that implements the ability to shutdown your 1976 current kernel, and to start another kernel. It is like a reboot 1977 but it is independent of the system firmware. And like a reboot 1978 you can start any kernel with it, not just Linux. 1979 1980 The name comes from the similarity to the exec system call. 1981 1982 It is an ongoing process to be certain the hardware in a machine 1983 is properly shutdown, so do not be surprised if this code does not 1984 initially work for you. As of this writing the exact hardware 1985 interface is strongly in flux, so no good recommendation can be 1986 made. 1987 1988config KEXEC_FILE 1989 bool "kexec file based system call" 1990 select KEXEC_CORE 1991 select BUILD_BIN2C 1992 depends on X86_64 1993 depends on CRYPTO=y 1994 depends on CRYPTO_SHA256=y 1995 ---help--- 1996 This is new version of kexec system call. This system call is 1997 file based and takes file descriptors as system call argument 1998 for kernel and initramfs as opposed to list of segments as 1999 accepted by previous system call. 2000 2001config ARCH_HAS_KEXEC_PURGATORY 2002 def_bool KEXEC_FILE 2003 2004config KEXEC_VERIFY_SIG 2005 bool "Verify kernel signature during kexec_file_load() syscall" 2006 depends on KEXEC_FILE 2007 ---help--- 2008 This option makes kernel signature verification mandatory for 2009 the kexec_file_load() syscall. 2010 2011 In addition to that option, you need to enable signature 2012 verification for the corresponding kernel image type being 2013 loaded in order for this to work. 2014 2015config KEXEC_BZIMAGE_VERIFY_SIG 2016 bool "Enable bzImage signature verification support" 2017 depends on KEXEC_VERIFY_SIG 2018 depends on SIGNED_PE_FILE_VERIFICATION 2019 select SYSTEM_TRUSTED_KEYRING 2020 ---help--- 2021 Enable bzImage signature verification support. 2022 2023config CRASH_DUMP 2024 bool "kernel crash dumps" 2025 depends on X86_64 || (X86_32 && HIGHMEM) 2026 ---help--- 2027 Generate crash dump after being started by kexec. 2028 This should be normally only set in special crash dump kernels 2029 which are loaded in the main kernel with kexec-tools into 2030 a specially reserved region and then later executed after 2031 a crash by kdump/kexec. The crash dump kernel must be compiled 2032 to a memory address not used by the main kernel or BIOS using 2033 PHYSICAL_START, or it must be built as a relocatable image 2034 (CONFIG_RELOCATABLE=y). 2035 For more details see Documentation/kdump/kdump.txt 2036 2037config KEXEC_JUMP 2038 bool "kexec jump" 2039 depends on KEXEC && HIBERNATION 2040 ---help--- 2041 Jump between original kernel and kexeced kernel and invoke 2042 code in physical address mode via KEXEC 2043 2044config PHYSICAL_START 2045 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2046 default "0x1000000" 2047 ---help--- 2048 This gives the physical address where the kernel is loaded. 2049 2050 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2051 bzImage will decompress itself to above physical address and 2052 run from there. Otherwise, bzImage will run from the address where 2053 it has been loaded by the boot loader and will ignore above physical 2054 address. 2055 2056 In normal kdump cases one does not have to set/change this option 2057 as now bzImage can be compiled as a completely relocatable image 2058 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2059 address. This option is mainly useful for the folks who don't want 2060 to use a bzImage for capturing the crash dump and want to use a 2061 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2062 to be specifically compiled to run from a specific memory area 2063 (normally a reserved region) and this option comes handy. 2064 2065 So if you are using bzImage for capturing the crash dump, 2066 leave the value here unchanged to 0x1000000 and set 2067 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2068 for capturing the crash dump change this value to start of 2069 the reserved region. In other words, it can be set based on 2070 the "X" value as specified in the "crashkernel=YM@XM" 2071 command line boot parameter passed to the panic-ed 2072 kernel. Please take a look at Documentation/kdump/kdump.txt 2073 for more details about crash dumps. 2074 2075 Usage of bzImage for capturing the crash dump is recommended as 2076 one does not have to build two kernels. Same kernel can be used 2077 as production kernel and capture kernel. Above option should have 2078 gone away after relocatable bzImage support is introduced. But it 2079 is present because there are users out there who continue to use 2080 vmlinux for dump capture. This option should go away down the 2081 line. 2082 2083 Don't change this unless you know what you are doing. 2084 2085config RELOCATABLE 2086 bool "Build a relocatable kernel" 2087 default y 2088 ---help--- 2089 This builds a kernel image that retains relocation information 2090 so it can be loaded someplace besides the default 1MB. 2091 The relocations tend to make the kernel binary about 10% larger, 2092 but are discarded at runtime. 2093 2094 One use is for the kexec on panic case where the recovery kernel 2095 must live at a different physical address than the primary 2096 kernel. 2097 2098 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2099 it has been loaded at and the compile time physical address 2100 (CONFIG_PHYSICAL_START) is used as the minimum location. 2101 2102config RANDOMIZE_BASE 2103 bool "Randomize the address of the kernel image (KASLR)" 2104 depends on RELOCATABLE 2105 default y 2106 ---help--- 2107 In support of Kernel Address Space Layout Randomization (KASLR), 2108 this randomizes the physical address at which the kernel image 2109 is decompressed and the virtual address where the kernel 2110 image is mapped, as a security feature that deters exploit 2111 attempts relying on knowledge of the location of kernel 2112 code internals. 2113 2114 On 64-bit, the kernel physical and virtual addresses are 2115 randomized separately. The physical address will be anywhere 2116 between 16MB and the top of physical memory (up to 64TB). The 2117 virtual address will be randomized from 16MB up to 1GB (9 bits 2118 of entropy). Note that this also reduces the memory space 2119 available to kernel modules from 1.5GB to 1GB. 2120 2121 On 32-bit, the kernel physical and virtual addresses are 2122 randomized together. They will be randomized from 16MB up to 2123 512MB (8 bits of entropy). 2124 2125 Entropy is generated using the RDRAND instruction if it is 2126 supported. If RDTSC is supported, its value is mixed into 2127 the entropy pool as well. If neither RDRAND nor RDTSC are 2128 supported, then entropy is read from the i8254 timer. The 2129 usable entropy is limited by the kernel being built using 2130 2GB addressing, and that PHYSICAL_ALIGN must be at a 2131 minimum of 2MB. As a result, only 10 bits of entropy are 2132 theoretically possible, but the implementations are further 2133 limited due to memory layouts. 2134 2135 If unsure, say Y. 2136 2137# Relocation on x86 needs some additional build support 2138config X86_NEED_RELOCS 2139 def_bool y 2140 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2141 2142config PHYSICAL_ALIGN 2143 hex "Alignment value to which kernel should be aligned" 2144 default "0x200000" 2145 range 0x2000 0x1000000 if X86_32 2146 range 0x200000 0x1000000 if X86_64 2147 ---help--- 2148 This value puts the alignment restrictions on physical address 2149 where kernel is loaded and run from. Kernel is compiled for an 2150 address which meets above alignment restriction. 2151 2152 If bootloader loads the kernel at a non-aligned address and 2153 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2154 address aligned to above value and run from there. 2155 2156 If bootloader loads the kernel at a non-aligned address and 2157 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2158 load address and decompress itself to the address it has been 2159 compiled for and run from there. The address for which kernel is 2160 compiled already meets above alignment restrictions. Hence the 2161 end result is that kernel runs from a physical address meeting 2162 above alignment restrictions. 2163 2164 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2165 this value must be a multiple of 0x200000. 2166 2167 Don't change this unless you know what you are doing. 2168 2169config DYNAMIC_MEMORY_LAYOUT 2170 bool 2171 ---help--- 2172 This option makes base addresses of vmalloc and vmemmap as well as 2173 __PAGE_OFFSET movable during boot. 2174 2175config RANDOMIZE_MEMORY 2176 bool "Randomize the kernel memory sections" 2177 depends on X86_64 2178 depends on RANDOMIZE_BASE 2179 select DYNAMIC_MEMORY_LAYOUT 2180 default RANDOMIZE_BASE 2181 ---help--- 2182 Randomizes the base virtual address of kernel memory sections 2183 (physical memory mapping, vmalloc & vmemmap). This security feature 2184 makes exploits relying on predictable memory locations less reliable. 2185 2186 The order of allocations remains unchanged. Entropy is generated in 2187 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2188 configuration have in average 30,000 different possible virtual 2189 addresses for each memory section. 2190 2191 If unsure, say Y. 2192 2193config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2194 hex "Physical memory mapping padding" if EXPERT 2195 depends on RANDOMIZE_MEMORY 2196 default "0xa" if MEMORY_HOTPLUG 2197 default "0x0" 2198 range 0x1 0x40 if MEMORY_HOTPLUG 2199 range 0x0 0x40 2200 ---help--- 2201 Define the padding in terabytes added to the existing physical 2202 memory size during kernel memory randomization. It is useful 2203 for memory hotplug support but reduces the entropy available for 2204 address randomization. 2205 2206 If unsure, leave at the default value. 2207 2208config HOTPLUG_CPU 2209 def_bool y 2210 depends on SMP 2211 2212config BOOTPARAM_HOTPLUG_CPU0 2213 bool "Set default setting of cpu0_hotpluggable" 2214 depends on HOTPLUG_CPU 2215 ---help--- 2216 Set whether default state of cpu0_hotpluggable is on or off. 2217 2218 Say Y here to enable CPU0 hotplug by default. If this switch 2219 is turned on, there is no need to give cpu0_hotplug kernel 2220 parameter and the CPU0 hotplug feature is enabled by default. 2221 2222 Please note: there are two known CPU0 dependencies if you want 2223 to enable the CPU0 hotplug feature either by this switch or by 2224 cpu0_hotplug kernel parameter. 2225 2226 First, resume from hibernate or suspend always starts from CPU0. 2227 So hibernate and suspend are prevented if CPU0 is offline. 2228 2229 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2230 offline if any interrupt can not migrate out of CPU0. There may 2231 be other CPU0 dependencies. 2232 2233 Please make sure the dependencies are under your control before 2234 you enable this feature. 2235 2236 Say N if you don't want to enable CPU0 hotplug feature by default. 2237 You still can enable the CPU0 hotplug feature at boot by kernel 2238 parameter cpu0_hotplug. 2239 2240config DEBUG_HOTPLUG_CPU0 2241 def_bool n 2242 prompt "Debug CPU0 hotplug" 2243 depends on HOTPLUG_CPU 2244 ---help--- 2245 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2246 soon as possible and boots up userspace with CPU0 offlined. User 2247 can online CPU0 back after boot time. 2248 2249 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2250 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2251 compilation or giving cpu0_hotplug kernel parameter at boot. 2252 2253 If unsure, say N. 2254 2255config COMPAT_VDSO 2256 def_bool n 2257 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2258 depends on COMPAT_32 2259 ---help--- 2260 Certain buggy versions of glibc will crash if they are 2261 presented with a 32-bit vDSO that is not mapped at the address 2262 indicated in its segment table. 2263 2264 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2265 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2266 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2267 the only released version with the bug, but OpenSUSE 9 2268 contains a buggy "glibc 2.3.2". 2269 2270 The symptom of the bug is that everything crashes on startup, saying: 2271 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2272 2273 Saying Y here changes the default value of the vdso32 boot 2274 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2275 This works around the glibc bug but hurts performance. 2276 2277 If unsure, say N: if you are compiling your own kernel, you 2278 are unlikely to be using a buggy version of glibc. 2279 2280choice 2281 prompt "vsyscall table for legacy applications" 2282 depends on X86_64 2283 default LEGACY_VSYSCALL_EMULATE 2284 help 2285 Legacy user code that does not know how to find the vDSO expects 2286 to be able to issue three syscalls by calling fixed addresses in 2287 kernel space. Since this location is not randomized with ASLR, 2288 it can be used to assist security vulnerability exploitation. 2289 2290 This setting can be changed at boot time via the kernel command 2291 line parameter vsyscall=[emulate|none]. 2292 2293 On a system with recent enough glibc (2.14 or newer) and no 2294 static binaries, you can say None without a performance penalty 2295 to improve security. 2296 2297 If unsure, select "Emulate". 2298 2299 config LEGACY_VSYSCALL_EMULATE 2300 bool "Emulate" 2301 help 2302 The kernel traps and emulates calls into the fixed 2303 vsyscall address mapping. This makes the mapping 2304 non-executable, but it still contains known contents, 2305 which could be used in certain rare security vulnerability 2306 exploits. This configuration is recommended when userspace 2307 still uses the vsyscall area. 2308 2309 config LEGACY_VSYSCALL_NONE 2310 bool "None" 2311 help 2312 There will be no vsyscall mapping at all. This will 2313 eliminate any risk of ASLR bypass due to the vsyscall 2314 fixed address mapping. Attempts to use the vsyscalls 2315 will be reported to dmesg, so that either old or 2316 malicious userspace programs can be identified. 2317 2318endchoice 2319 2320config CMDLINE_BOOL 2321 bool "Built-in kernel command line" 2322 ---help--- 2323 Allow for specifying boot arguments to the kernel at 2324 build time. On some systems (e.g. embedded ones), it is 2325 necessary or convenient to provide some or all of the 2326 kernel boot arguments with the kernel itself (that is, 2327 to not rely on the boot loader to provide them.) 2328 2329 To compile command line arguments into the kernel, 2330 set this option to 'Y', then fill in the 2331 boot arguments in CONFIG_CMDLINE. 2332 2333 Systems with fully functional boot loaders (i.e. non-embedded) 2334 should leave this option set to 'N'. 2335 2336config CMDLINE 2337 string "Built-in kernel command string" 2338 depends on CMDLINE_BOOL 2339 default "" 2340 ---help--- 2341 Enter arguments here that should be compiled into the kernel 2342 image and used at boot time. If the boot loader provides a 2343 command line at boot time, it is appended to this string to 2344 form the full kernel command line, when the system boots. 2345 2346 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2347 change this behavior. 2348 2349 In most cases, the command line (whether built-in or provided 2350 by the boot loader) should specify the device for the root 2351 file system. 2352 2353config CMDLINE_OVERRIDE 2354 bool "Built-in command line overrides boot loader arguments" 2355 depends on CMDLINE_BOOL 2356 ---help--- 2357 Set this option to 'Y' to have the kernel ignore the boot loader 2358 command line, and use ONLY the built-in command line. 2359 2360 This is used to work around broken boot loaders. This should 2361 be set to 'N' under normal conditions. 2362 2363config MODIFY_LDT_SYSCALL 2364 bool "Enable the LDT (local descriptor table)" if EXPERT 2365 default y 2366 ---help--- 2367 Linux can allow user programs to install a per-process x86 2368 Local Descriptor Table (LDT) using the modify_ldt(2) system 2369 call. This is required to run 16-bit or segmented code such as 2370 DOSEMU or some Wine programs. It is also used by some very old 2371 threading libraries. 2372 2373 Enabling this feature adds a small amount of overhead to 2374 context switches and increases the low-level kernel attack 2375 surface. Disabling it removes the modify_ldt(2) system call. 2376 2377 Saying 'N' here may make sense for embedded or server kernels. 2378 2379source "kernel/livepatch/Kconfig" 2380 2381endmenu 2382 2383config ARCH_HAS_ADD_PAGES 2384 def_bool y 2385 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2386 2387config ARCH_ENABLE_MEMORY_HOTPLUG 2388 def_bool y 2389 depends on X86_64 || (X86_32 && HIGHMEM) 2390 2391config ARCH_ENABLE_MEMORY_HOTREMOVE 2392 def_bool y 2393 depends on MEMORY_HOTPLUG 2394 2395config USE_PERCPU_NUMA_NODE_ID 2396 def_bool y 2397 depends on NUMA 2398 2399config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2400 def_bool y 2401 depends on X86_64 || X86_PAE 2402 2403config ARCH_ENABLE_HUGEPAGE_MIGRATION 2404 def_bool y 2405 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2406 2407config ARCH_ENABLE_THP_MIGRATION 2408 def_bool y 2409 depends on X86_64 && TRANSPARENT_HUGEPAGE 2410 2411menu "Power management and ACPI options" 2412 2413config ARCH_HIBERNATION_HEADER 2414 def_bool y 2415 depends on HIBERNATION 2416 2417source "kernel/power/Kconfig" 2418 2419source "drivers/acpi/Kconfig" 2420 2421source "drivers/sfi/Kconfig" 2422 2423config X86_APM_BOOT 2424 def_bool y 2425 depends on APM 2426 2427menuconfig APM 2428 tristate "APM (Advanced Power Management) BIOS support" 2429 depends on X86_32 && PM_SLEEP 2430 ---help--- 2431 APM is a BIOS specification for saving power using several different 2432 techniques. This is mostly useful for battery powered laptops with 2433 APM compliant BIOSes. If you say Y here, the system time will be 2434 reset after a RESUME operation, the /proc/apm device will provide 2435 battery status information, and user-space programs will receive 2436 notification of APM "events" (e.g. battery status change). 2437 2438 If you select "Y" here, you can disable actual use of the APM 2439 BIOS by passing the "apm=off" option to the kernel at boot time. 2440 2441 Note that the APM support is almost completely disabled for 2442 machines with more than one CPU. 2443 2444 In order to use APM, you will need supporting software. For location 2445 and more information, read <file:Documentation/power/apm-acpi.txt> 2446 and the Battery Powered Linux mini-HOWTO, available from 2447 <http://www.tldp.org/docs.html#howto>. 2448 2449 This driver does not spin down disk drives (see the hdparm(8) 2450 manpage ("man 8 hdparm") for that), and it doesn't turn off 2451 VESA-compliant "green" monitors. 2452 2453 This driver does not support the TI 4000M TravelMate and the ACER 2454 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2455 desktop machines also don't have compliant BIOSes, and this driver 2456 may cause those machines to panic during the boot phase. 2457 2458 Generally, if you don't have a battery in your machine, there isn't 2459 much point in using this driver and you should say N. If you get 2460 random kernel OOPSes or reboots that don't seem to be related to 2461 anything, try disabling/enabling this option (or disabling/enabling 2462 APM in your BIOS). 2463 2464 Some other things you should try when experiencing seemingly random, 2465 "weird" problems: 2466 2467 1) make sure that you have enough swap space and that it is 2468 enabled. 2469 2) pass the "no-hlt" option to the kernel 2470 3) switch on floating point emulation in the kernel and pass 2471 the "no387" option to the kernel 2472 4) pass the "floppy=nodma" option to the kernel 2473 5) pass the "mem=4M" option to the kernel (thereby disabling 2474 all but the first 4 MB of RAM) 2475 6) make sure that the CPU is not over clocked. 2476 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2477 8) disable the cache from your BIOS settings 2478 9) install a fan for the video card or exchange video RAM 2479 10) install a better fan for the CPU 2480 11) exchange RAM chips 2481 12) exchange the motherboard. 2482 2483 To compile this driver as a module, choose M here: the 2484 module will be called apm. 2485 2486if APM 2487 2488config APM_IGNORE_USER_SUSPEND 2489 bool "Ignore USER SUSPEND" 2490 ---help--- 2491 This option will ignore USER SUSPEND requests. On machines with a 2492 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2493 series notebooks, it is necessary to say Y because of a BIOS bug. 2494 2495config APM_DO_ENABLE 2496 bool "Enable PM at boot time" 2497 ---help--- 2498 Enable APM features at boot time. From page 36 of the APM BIOS 2499 specification: "When disabled, the APM BIOS does not automatically 2500 power manage devices, enter the Standby State, enter the Suspend 2501 State, or take power saving steps in response to CPU Idle calls." 2502 This driver will make CPU Idle calls when Linux is idle (unless this 2503 feature is turned off -- see "Do CPU IDLE calls", below). This 2504 should always save battery power, but more complicated APM features 2505 will be dependent on your BIOS implementation. You may need to turn 2506 this option off if your computer hangs at boot time when using APM 2507 support, or if it beeps continuously instead of suspending. Turn 2508 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2509 T400CDT. This is off by default since most machines do fine without 2510 this feature. 2511 2512config APM_CPU_IDLE 2513 depends on CPU_IDLE 2514 bool "Make CPU Idle calls when idle" 2515 ---help--- 2516 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2517 On some machines, this can activate improved power savings, such as 2518 a slowed CPU clock rate, when the machine is idle. These idle calls 2519 are made after the idle loop has run for some length of time (e.g., 2520 333 mS). On some machines, this will cause a hang at boot time or 2521 whenever the CPU becomes idle. (On machines with more than one CPU, 2522 this option does nothing.) 2523 2524config APM_DISPLAY_BLANK 2525 bool "Enable console blanking using APM" 2526 ---help--- 2527 Enable console blanking using the APM. Some laptops can use this to 2528 turn off the LCD backlight when the screen blanker of the Linux 2529 virtual console blanks the screen. Note that this is only used by 2530 the virtual console screen blanker, and won't turn off the backlight 2531 when using the X Window system. This also doesn't have anything to 2532 do with your VESA-compliant power-saving monitor. Further, this 2533 option doesn't work for all laptops -- it might not turn off your 2534 backlight at all, or it might print a lot of errors to the console, 2535 especially if you are using gpm. 2536 2537config APM_ALLOW_INTS 2538 bool "Allow interrupts during APM BIOS calls" 2539 ---help--- 2540 Normally we disable external interrupts while we are making calls to 2541 the APM BIOS as a measure to lessen the effects of a badly behaving 2542 BIOS implementation. The BIOS should reenable interrupts if it 2543 needs to. Unfortunately, some BIOSes do not -- especially those in 2544 many of the newer IBM Thinkpads. If you experience hangs when you 2545 suspend, try setting this to Y. Otherwise, say N. 2546 2547endif # APM 2548 2549source "drivers/cpufreq/Kconfig" 2550 2551source "drivers/cpuidle/Kconfig" 2552 2553source "drivers/idle/Kconfig" 2554 2555endmenu 2556 2557 2558menu "Bus options (PCI etc.)" 2559 2560choice 2561 prompt "PCI access mode" 2562 depends on X86_32 && PCI 2563 default PCI_GOANY 2564 ---help--- 2565 On PCI systems, the BIOS can be used to detect the PCI devices and 2566 determine their configuration. However, some old PCI motherboards 2567 have BIOS bugs and may crash if this is done. Also, some embedded 2568 PCI-based systems don't have any BIOS at all. Linux can also try to 2569 detect the PCI hardware directly without using the BIOS. 2570 2571 With this option, you can specify how Linux should detect the 2572 PCI devices. If you choose "BIOS", the BIOS will be used, 2573 if you choose "Direct", the BIOS won't be used, and if you 2574 choose "MMConfig", then PCI Express MMCONFIG will be used. 2575 If you choose "Any", the kernel will try MMCONFIG, then the 2576 direct access method and falls back to the BIOS if that doesn't 2577 work. If unsure, go with the default, which is "Any". 2578 2579config PCI_GOBIOS 2580 bool "BIOS" 2581 2582config PCI_GOMMCONFIG 2583 bool "MMConfig" 2584 2585config PCI_GODIRECT 2586 bool "Direct" 2587 2588config PCI_GOOLPC 2589 bool "OLPC XO-1" 2590 depends on OLPC 2591 2592config PCI_GOANY 2593 bool "Any" 2594 2595endchoice 2596 2597config PCI_BIOS 2598 def_bool y 2599 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2600 2601# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2602config PCI_DIRECT 2603 def_bool y 2604 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2605 2606config PCI_MMCONFIG 2607 bool "Support mmconfig PCI config space access" if X86_64 2608 default y 2609 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2610 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2611 2612config PCI_OLPC 2613 def_bool y 2614 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2615 2616config PCI_XEN 2617 def_bool y 2618 depends on PCI && XEN 2619 select SWIOTLB_XEN 2620 2621config MMCONF_FAM10H 2622 def_bool y 2623 depends on X86_64 && PCI_MMCONFIG && ACPI 2624 2625config PCI_CNB20LE_QUIRK 2626 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2627 depends on PCI 2628 help 2629 Read the PCI windows out of the CNB20LE host bridge. This allows 2630 PCI hotplug to work on systems with the CNB20LE chipset which do 2631 not have ACPI. 2632 2633 There's no public spec for this chipset, and this functionality 2634 is known to be incomplete. 2635 2636 You should say N unless you know you need this. 2637 2638config ISA_BUS 2639 bool "ISA bus support on modern systems" if EXPERT 2640 help 2641 Expose ISA bus device drivers and options available for selection and 2642 configuration. Enable this option if your target machine has an ISA 2643 bus. ISA is an older system, displaced by PCI and newer bus 2644 architectures -- if your target machine is modern, it probably does 2645 not have an ISA bus. 2646 2647 If unsure, say N. 2648 2649# x86_64 have no ISA slots, but can have ISA-style DMA. 2650config ISA_DMA_API 2651 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2652 default y 2653 help 2654 Enables ISA-style DMA support for devices requiring such controllers. 2655 If unsure, say Y. 2656 2657if X86_32 2658 2659config ISA 2660 bool "ISA support" 2661 ---help--- 2662 Find out whether you have ISA slots on your motherboard. ISA is the 2663 name of a bus system, i.e. the way the CPU talks to the other stuff 2664 inside your box. Other bus systems are PCI, EISA, MicroChannel 2665 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2666 newer boards don't support it. If you have ISA, say Y, otherwise N. 2667 2668config SCx200 2669 tristate "NatSemi SCx200 support" 2670 ---help--- 2671 This provides basic support for National Semiconductor's 2672 (now AMD's) Geode processors. The driver probes for the 2673 PCI-IDs of several on-chip devices, so its a good dependency 2674 for other scx200_* drivers. 2675 2676 If compiled as a module, the driver is named scx200. 2677 2678config SCx200HR_TIMER 2679 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2680 depends on SCx200 2681 default y 2682 ---help--- 2683 This driver provides a clocksource built upon the on-chip 2684 27MHz high-resolution timer. Its also a workaround for 2685 NSC Geode SC-1100's buggy TSC, which loses time when the 2686 processor goes idle (as is done by the scheduler). The 2687 other workaround is idle=poll boot option. 2688 2689config OLPC 2690 bool "One Laptop Per Child support" 2691 depends on !X86_PAE 2692 select GPIOLIB 2693 select OF 2694 select OF_PROMTREE 2695 select IRQ_DOMAIN 2696 ---help--- 2697 Add support for detecting the unique features of the OLPC 2698 XO hardware. 2699 2700config OLPC_XO1_PM 2701 bool "OLPC XO-1 Power Management" 2702 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2703 ---help--- 2704 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2705 2706config OLPC_XO1_RTC 2707 bool "OLPC XO-1 Real Time Clock" 2708 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2709 ---help--- 2710 Add support for the XO-1 real time clock, which can be used as a 2711 programmable wakeup source. 2712 2713config OLPC_XO1_SCI 2714 bool "OLPC XO-1 SCI extras" 2715 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2716 depends on INPUT=y 2717 select POWER_SUPPLY 2718 ---help--- 2719 Add support for SCI-based features of the OLPC XO-1 laptop: 2720 - EC-driven system wakeups 2721 - Power button 2722 - Ebook switch 2723 - Lid switch 2724 - AC adapter status updates 2725 - Battery status updates 2726 2727config OLPC_XO15_SCI 2728 bool "OLPC XO-1.5 SCI extras" 2729 depends on OLPC && ACPI 2730 select POWER_SUPPLY 2731 ---help--- 2732 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2733 - EC-driven system wakeups 2734 - AC adapter status updates 2735 - Battery status updates 2736 2737config ALIX 2738 bool "PCEngines ALIX System Support (LED setup)" 2739 select GPIOLIB 2740 ---help--- 2741 This option enables system support for the PCEngines ALIX. 2742 At present this just sets up LEDs for GPIO control on 2743 ALIX2/3/6 boards. However, other system specific setup should 2744 get added here. 2745 2746 Note: You must still enable the drivers for GPIO and LED support 2747 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2748 2749 Note: You have to set alix.force=1 for boards with Award BIOS. 2750 2751config NET5501 2752 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2753 select GPIOLIB 2754 ---help--- 2755 This option enables system support for the Soekris Engineering net5501. 2756 2757config GEOS 2758 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2759 select GPIOLIB 2760 depends on DMI 2761 ---help--- 2762 This option enables system support for the Traverse Technologies GEOS. 2763 2764config TS5500 2765 bool "Technologic Systems TS-5500 platform support" 2766 depends on MELAN 2767 select CHECK_SIGNATURE 2768 select NEW_LEDS 2769 select LEDS_CLASS 2770 ---help--- 2771 This option enables system support for the Technologic Systems TS-5500. 2772 2773endif # X86_32 2774 2775config AMD_NB 2776 def_bool y 2777 depends on CPU_SUP_AMD && PCI 2778 2779config X86_SYSFB 2780 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2781 help 2782 Firmwares often provide initial graphics framebuffers so the BIOS, 2783 bootloader or kernel can show basic video-output during boot for 2784 user-guidance and debugging. Historically, x86 used the VESA BIOS 2785 Extensions and EFI-framebuffers for this, which are mostly limited 2786 to x86. 2787 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2788 framebuffers so the new generic system-framebuffer drivers can be 2789 used on x86. If the framebuffer is not compatible with the generic 2790 modes, it is advertised as fallback platform framebuffer so legacy 2791 drivers like efifb, vesafb and uvesafb can pick it up. 2792 If this option is not selected, all system framebuffers are always 2793 marked as fallback platform framebuffers as usual. 2794 2795 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2796 not be able to pick up generic system framebuffers if this option 2797 is selected. You are highly encouraged to enable simplefb as 2798 replacement if you select this option. simplefb can correctly deal 2799 with generic system framebuffers. But you should still keep vesafb 2800 and others enabled as fallback if a system framebuffer is 2801 incompatible with simplefb. 2802 2803 If unsure, say Y. 2804 2805endmenu 2806 2807 2808menu "Binary Emulations" 2809 2810config IA32_EMULATION 2811 bool "IA32 Emulation" 2812 depends on X86_64 2813 select ARCH_WANT_OLD_COMPAT_IPC 2814 select BINFMT_ELF 2815 select COMPAT_BINFMT_ELF 2816 select COMPAT_OLD_SIGACTION 2817 ---help--- 2818 Include code to run legacy 32-bit programs under a 2819 64-bit kernel. You should likely turn this on, unless you're 2820 100% sure that you don't have any 32-bit programs left. 2821 2822config IA32_AOUT 2823 tristate "IA32 a.out support" 2824 depends on IA32_EMULATION 2825 depends on BROKEN 2826 ---help--- 2827 Support old a.out binaries in the 32bit emulation. 2828 2829config X86_X32 2830 bool "x32 ABI for 64-bit mode" 2831 depends on X86_64 2832 ---help--- 2833 Include code to run binaries for the x32 native 32-bit ABI 2834 for 64-bit processors. An x32 process gets access to the 2835 full 64-bit register file and wide data path while leaving 2836 pointers at 32 bits for smaller memory footprint. 2837 2838 You will need a recent binutils (2.22 or later) with 2839 elf32_x86_64 support enabled to compile a kernel with this 2840 option set. 2841 2842config COMPAT_32 2843 def_bool y 2844 depends on IA32_EMULATION || X86_32 2845 select HAVE_UID16 2846 select OLD_SIGSUSPEND3 2847 2848config COMPAT 2849 def_bool y 2850 depends on IA32_EMULATION || X86_X32 2851 2852if COMPAT 2853config COMPAT_FOR_U64_ALIGNMENT 2854 def_bool y 2855 2856config SYSVIPC_COMPAT 2857 def_bool y 2858 depends on SYSVIPC 2859endif 2860 2861endmenu 2862 2863 2864config HAVE_ATOMIC_IOMAP 2865 def_bool y 2866 depends on X86_32 2867 2868config X86_DEV_DMA_OPS 2869 bool 2870 2871config HAVE_GENERIC_GUP 2872 def_bool y 2873 2874source "drivers/firmware/Kconfig" 2875 2876source "arch/x86/kvm/Kconfig" 2877