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 if (MEMORY_ISOLATION && COMPACTION) || CMA 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 ANON_INODES 48 select ARCH_32BIT_OFF_T if X86_32 49 select ARCH_CLOCKSOURCE_DATA 50 select ARCH_CLOCKSOURCE_INIT 51 select ARCH_DISCARD_MEMBLOCK 52 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 53 select ARCH_HAS_DEBUG_VIRTUAL 54 select ARCH_HAS_DEVMEM_IS_ALLOWED 55 select ARCH_HAS_ELF_RANDOMIZE 56 select ARCH_HAS_FAST_MULTIPLIER 57 select ARCH_HAS_FILTER_PGPROT 58 select ARCH_HAS_FORTIFY_SOURCE 59 select ARCH_HAS_GCOV_PROFILE_ALL 60 select ARCH_HAS_KCOV if X86_64 61 select ARCH_HAS_MEMBARRIER_SYNC_CORE 62 select ARCH_HAS_PMEM_API if X86_64 63 select ARCH_HAS_PTE_SPECIAL 64 select ARCH_HAS_REFCOUNT 65 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 66 select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE 67 select ARCH_HAS_SET_MEMORY 68 select ARCH_HAS_SET_DIRECT_MAP 69 select ARCH_HAS_STRICT_KERNEL_RWX 70 select ARCH_HAS_STRICT_MODULE_RWX 71 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 72 select ARCH_HAS_UBSAN_SANITIZE_ALL 73 select ARCH_HAS_ZONE_DEVICE if X86_64 74 select ARCH_HAVE_NMI_SAFE_CMPXCHG 75 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 76 select ARCH_MIGHT_HAVE_PC_PARPORT 77 select ARCH_MIGHT_HAVE_PC_SERIO 78 select ARCH_STACKWALK 79 select ARCH_SUPPORTS_ACPI 80 select ARCH_SUPPORTS_ATOMIC_RMW 81 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 82 select ARCH_USE_BUILTIN_BSWAP 83 select ARCH_USE_QUEUED_RWLOCKS 84 select ARCH_USE_QUEUED_SPINLOCKS 85 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 86 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 87 select ARCH_WANTS_THP_SWAP if X86_64 88 select BUILDTIME_EXTABLE_SORT 89 select CLKEVT_I8253 90 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 91 select CLOCKSOURCE_WATCHDOG 92 select DCACHE_WORD_ACCESS 93 select EDAC_ATOMIC_SCRUB 94 select EDAC_SUPPORT 95 select GENERIC_CLOCKEVENTS 96 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 97 select GENERIC_CLOCKEVENTS_MIN_ADJUST 98 select GENERIC_CMOS_UPDATE 99 select GENERIC_CPU_AUTOPROBE 100 select GENERIC_CPU_VULNERABILITIES 101 select GENERIC_EARLY_IOREMAP 102 select GENERIC_FIND_FIRST_BIT 103 select GENERIC_IOMAP 104 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 105 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 106 select GENERIC_IRQ_MIGRATION if SMP 107 select GENERIC_IRQ_PROBE 108 select GENERIC_IRQ_RESERVATION_MODE 109 select GENERIC_IRQ_SHOW 110 select GENERIC_PENDING_IRQ if SMP 111 select GENERIC_SMP_IDLE_THREAD 112 select GENERIC_STRNCPY_FROM_USER 113 select GENERIC_STRNLEN_USER 114 select GENERIC_TIME_VSYSCALL 115 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 116 select HAVE_ACPI_APEI if ACPI 117 select HAVE_ACPI_APEI_NMI if ACPI 118 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 119 select HAVE_ARCH_AUDITSYSCALL 120 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 121 select HAVE_ARCH_JUMP_LABEL 122 select HAVE_ARCH_JUMP_LABEL_RELATIVE 123 select HAVE_ARCH_KASAN if X86_64 124 select HAVE_ARCH_KGDB 125 select HAVE_ARCH_MMAP_RND_BITS if MMU 126 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 127 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 128 select HAVE_ARCH_PREL32_RELOCATIONS 129 select HAVE_ARCH_SECCOMP_FILTER 130 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 131 select HAVE_ARCH_STACKLEAK 132 select HAVE_ARCH_TRACEHOOK 133 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 134 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 135 select HAVE_ARCH_VMAP_STACK if X86_64 136 select HAVE_ARCH_WITHIN_STACK_FRAMES 137 select HAVE_CMPXCHG_DOUBLE 138 select HAVE_CMPXCHG_LOCAL 139 select HAVE_CONTEXT_TRACKING if X86_64 140 select HAVE_COPY_THREAD_TLS 141 select HAVE_C_RECORDMCOUNT 142 select HAVE_DEBUG_KMEMLEAK 143 select HAVE_DMA_CONTIGUOUS 144 select HAVE_DYNAMIC_FTRACE 145 select HAVE_DYNAMIC_FTRACE_WITH_REGS 146 select HAVE_EBPF_JIT 147 select HAVE_EFFICIENT_UNALIGNED_ACCESS 148 select HAVE_EISA 149 select HAVE_EXIT_THREAD 150 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 151 select HAVE_FTRACE_MCOUNT_RECORD 152 select HAVE_FUNCTION_GRAPH_TRACER 153 select HAVE_FUNCTION_TRACER 154 select HAVE_GCC_PLUGINS 155 select HAVE_HW_BREAKPOINT 156 select HAVE_IDE 157 select HAVE_IOREMAP_PROT 158 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 159 select HAVE_IRQ_TIME_ACCOUNTING 160 select HAVE_KERNEL_BZIP2 161 select HAVE_KERNEL_GZIP 162 select HAVE_KERNEL_LZ4 163 select HAVE_KERNEL_LZMA 164 select HAVE_KERNEL_LZO 165 select HAVE_KERNEL_XZ 166 select HAVE_KPROBES 167 select HAVE_KPROBES_ON_FTRACE 168 select HAVE_FUNCTION_ERROR_INJECTION 169 select HAVE_KRETPROBES 170 select HAVE_KVM 171 select HAVE_LIVEPATCH if X86_64 172 select HAVE_MEMBLOCK_NODE_MAP 173 select HAVE_MIXED_BREAKPOINTS_REGS 174 select HAVE_MOD_ARCH_SPECIFIC 175 select HAVE_MOVE_PMD 176 select HAVE_NMI 177 select HAVE_OPROFILE 178 select HAVE_OPTPROBES 179 select HAVE_PCSPKR_PLATFORM 180 select HAVE_PERF_EVENTS 181 select HAVE_PERF_EVENTS_NMI 182 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 183 select HAVE_PCI 184 select HAVE_PERF_REGS 185 select HAVE_PERF_USER_STACK_DUMP 186 select HAVE_RCU_TABLE_FREE if PARAVIRT 187 select HAVE_REGS_AND_STACK_ACCESS_API 188 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 189 select HAVE_FUNCTION_ARG_ACCESS_API 190 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 191 select HAVE_STACK_VALIDATION if X86_64 192 select HAVE_RSEQ 193 select HAVE_SYSCALL_TRACEPOINTS 194 select HAVE_UNSTABLE_SCHED_CLOCK 195 select HAVE_USER_RETURN_NOTIFIER 196 select HOTPLUG_SMT if SMP 197 select IRQ_FORCED_THREADING 198 select NEED_SG_DMA_LENGTH 199 select PCI_DOMAINS if PCI 200 select PCI_LOCKLESS_CONFIG if PCI 201 select PERF_EVENTS 202 select RTC_LIB 203 select RTC_MC146818_LIB 204 select SPARSE_IRQ 205 select SRCU 206 select SYSCTL_EXCEPTION_TRACE 207 select THREAD_INFO_IN_TASK 208 select USER_STACKTRACE_SUPPORT 209 select VIRT_TO_BUS 210 select X86_FEATURE_NAMES if PROC_FS 211 212config INSTRUCTION_DECODER 213 def_bool y 214 depends on KPROBES || PERF_EVENTS || UPROBES 215 216config OUTPUT_FORMAT 217 string 218 default "elf32-i386" if X86_32 219 default "elf64-x86-64" if X86_64 220 221config ARCH_DEFCONFIG 222 string 223 default "arch/x86/configs/i386_defconfig" if X86_32 224 default "arch/x86/configs/x86_64_defconfig" if X86_64 225 226config LOCKDEP_SUPPORT 227 def_bool y 228 229config STACKTRACE_SUPPORT 230 def_bool y 231 232config MMU 233 def_bool y 234 235config ARCH_MMAP_RND_BITS_MIN 236 default 28 if 64BIT 237 default 8 238 239config ARCH_MMAP_RND_BITS_MAX 240 default 32 if 64BIT 241 default 16 242 243config ARCH_MMAP_RND_COMPAT_BITS_MIN 244 default 8 245 246config ARCH_MMAP_RND_COMPAT_BITS_MAX 247 default 16 248 249config SBUS 250 bool 251 252config GENERIC_ISA_DMA 253 def_bool y 254 depends on ISA_DMA_API 255 256config GENERIC_BUG 257 def_bool y 258 depends on BUG 259 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 260 261config GENERIC_BUG_RELATIVE_POINTERS 262 bool 263 264config GENERIC_HWEIGHT 265 def_bool y 266 267config ARCH_MAY_HAVE_PC_FDC 268 def_bool y 269 depends on ISA_DMA_API 270 271config GENERIC_CALIBRATE_DELAY 272 def_bool y 273 274config ARCH_HAS_CPU_RELAX 275 def_bool y 276 277config ARCH_HAS_CACHE_LINE_SIZE 278 def_bool y 279 280config ARCH_HAS_FILTER_PGPROT 281 def_bool y 282 283config HAVE_SETUP_PER_CPU_AREA 284 def_bool y 285 286config NEED_PER_CPU_EMBED_FIRST_CHUNK 287 def_bool y 288 289config NEED_PER_CPU_PAGE_FIRST_CHUNK 290 def_bool y 291 292config ARCH_HIBERNATION_POSSIBLE 293 def_bool y 294 295config ARCH_SUSPEND_POSSIBLE 296 def_bool y 297 298config ARCH_WANT_HUGE_PMD_SHARE 299 def_bool y 300 301config ARCH_WANT_GENERAL_HUGETLB 302 def_bool y 303 304config ZONE_DMA32 305 def_bool y if X86_64 306 307config AUDIT_ARCH 308 def_bool y if X86_64 309 310config ARCH_SUPPORTS_OPTIMIZED_INLINING 311 def_bool y 312 313config ARCH_SUPPORTS_DEBUG_PAGEALLOC 314 def_bool y 315 316config KASAN_SHADOW_OFFSET 317 hex 318 depends on KASAN 319 default 0xdffffc0000000000 320 321config HAVE_INTEL_TXT 322 def_bool y 323 depends on INTEL_IOMMU && ACPI 324 325config X86_32_SMP 326 def_bool y 327 depends on X86_32 && SMP 328 329config X86_64_SMP 330 def_bool y 331 depends on X86_64 && SMP 332 333config X86_32_LAZY_GS 334 def_bool y 335 depends on X86_32 && !STACKPROTECTOR 336 337config ARCH_SUPPORTS_UPROBES 338 def_bool y 339 340config FIX_EARLYCON_MEM 341 def_bool y 342 343config DYNAMIC_PHYSICAL_MASK 344 bool 345 346config PGTABLE_LEVELS 347 int 348 default 5 if X86_5LEVEL 349 default 4 if X86_64 350 default 3 if X86_PAE 351 default 2 352 353config CC_HAS_SANE_STACKPROTECTOR 354 bool 355 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 356 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 357 help 358 We have to make sure stack protector is unconditionally disabled if 359 the compiler produces broken code. 360 361menu "Processor type and features" 362 363config ZONE_DMA 364 bool "DMA memory allocation support" if EXPERT 365 default y 366 help 367 DMA memory allocation support allows devices with less than 32-bit 368 addressing to allocate within the first 16MB of address space. 369 Disable if no such devices will be used. 370 371 If unsure, say Y. 372 373config SMP 374 bool "Symmetric multi-processing support" 375 ---help--- 376 This enables support for systems with more than one CPU. If you have 377 a system with only one CPU, say N. If you have a system with more 378 than one CPU, say Y. 379 380 If you say N here, the kernel will run on uni- and multiprocessor 381 machines, but will use only one CPU of a multiprocessor machine. If 382 you say Y here, the kernel will run on many, but not all, 383 uniprocessor machines. On a uniprocessor machine, the kernel 384 will run faster if you say N here. 385 386 Note that if you say Y here and choose architecture "586" or 387 "Pentium" under "Processor family", the kernel will not work on 486 388 architectures. Similarly, multiprocessor kernels for the "PPro" 389 architecture may not work on all Pentium based boards. 390 391 People using multiprocessor machines who say Y here should also say 392 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 393 Management" code will be disabled if you say Y here. 394 395 See also <file:Documentation/x86/i386/IO-APIC.txt>, 396 <file:Documentation/lockup-watchdogs.txt> and the SMP-HOWTO available at 397 <http://www.tldp.org/docs.html#howto>. 398 399 If you don't know what to do here, say N. 400 401config X86_FEATURE_NAMES 402 bool "Processor feature human-readable names" if EMBEDDED 403 default y 404 ---help--- 405 This option compiles in a table of x86 feature bits and corresponding 406 names. This is required to support /proc/cpuinfo and a few kernel 407 messages. You can disable this to save space, at the expense of 408 making those few kernel messages show numeric feature bits instead. 409 410 If in doubt, say Y. 411 412config X86_X2APIC 413 bool "Support x2apic" 414 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 415 ---help--- 416 This enables x2apic support on CPUs that have this feature. 417 418 This allows 32-bit apic IDs (so it can support very large systems), 419 and accesses the local apic via MSRs not via mmio. 420 421 If you don't know what to do here, say N. 422 423config X86_MPPARSE 424 bool "Enable MPS table" if ACPI || SFI 425 default y 426 depends on X86_LOCAL_APIC 427 ---help--- 428 For old smp systems that do not have proper acpi support. Newer systems 429 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 430 431config GOLDFISH 432 def_bool y 433 depends on X86_GOLDFISH 434 435config RETPOLINE 436 bool "Avoid speculative indirect branches in kernel" 437 default y 438 select STACK_VALIDATION if HAVE_STACK_VALIDATION 439 help 440 Compile kernel with the retpoline compiler options to guard against 441 kernel-to-user data leaks by avoiding speculative indirect 442 branches. Requires a compiler with -mindirect-branch=thunk-extern 443 support for full protection. The kernel may run slower. 444 445config X86_CPU_RESCTRL 446 bool "x86 CPU resource control support" 447 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 448 select KERNFS 449 help 450 Enable x86 CPU resource control support. 451 452 Provide support for the allocation and monitoring of system resources 453 usage by the CPU. 454 455 Intel calls this Intel Resource Director Technology 456 (Intel(R) RDT). More information about RDT can be found in the 457 Intel x86 Architecture Software Developer Manual. 458 459 AMD calls this AMD Platform Quality of Service (AMD QoS). 460 More information about AMD QoS can be found in the AMD64 Technology 461 Platform Quality of Service Extensions manual. 462 463 Say N if unsure. 464 465if X86_32 466config X86_BIGSMP 467 bool "Support for big SMP systems with more than 8 CPUs" 468 depends on SMP 469 ---help--- 470 This option is needed for the systems that have more than 8 CPUs 471 472config X86_EXTENDED_PLATFORM 473 bool "Support for extended (non-PC) x86 platforms" 474 default y 475 ---help--- 476 If you disable this option then the kernel will only support 477 standard PC platforms. (which covers the vast majority of 478 systems out there.) 479 480 If you enable this option then you'll be able to select support 481 for the following (non-PC) 32 bit x86 platforms: 482 Goldfish (Android emulator) 483 AMD Elan 484 RDC R-321x SoC 485 SGI 320/540 (Visual Workstation) 486 STA2X11-based (e.g. Northville) 487 Moorestown MID devices 488 489 If you have one of these systems, or if you want to build a 490 generic distribution kernel, say Y here - otherwise say N. 491endif 492 493if X86_64 494config X86_EXTENDED_PLATFORM 495 bool "Support for extended (non-PC) x86 platforms" 496 default y 497 ---help--- 498 If you disable this option then the kernel will only support 499 standard PC platforms. (which covers the vast majority of 500 systems out there.) 501 502 If you enable this option then you'll be able to select support 503 for the following (non-PC) 64 bit x86 platforms: 504 Numascale NumaChip 505 ScaleMP vSMP 506 SGI Ultraviolet 507 508 If you have one of these systems, or if you want to build a 509 generic distribution kernel, say Y here - otherwise say N. 510endif 511# This is an alphabetically sorted list of 64 bit extended platforms 512# Please maintain the alphabetic order if and when there are additions 513config X86_NUMACHIP 514 bool "Numascale NumaChip" 515 depends on X86_64 516 depends on X86_EXTENDED_PLATFORM 517 depends on NUMA 518 depends on SMP 519 depends on X86_X2APIC 520 depends on PCI_MMCONFIG 521 ---help--- 522 Adds support for Numascale NumaChip large-SMP systems. Needed to 523 enable more than ~168 cores. 524 If you don't have one of these, you should say N here. 525 526config X86_VSMP 527 bool "ScaleMP vSMP" 528 select HYPERVISOR_GUEST 529 select PARAVIRT 530 depends on X86_64 && PCI 531 depends on X86_EXTENDED_PLATFORM 532 depends on SMP 533 ---help--- 534 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 535 supposed to run on these EM64T-based machines. Only choose this option 536 if you have one of these machines. 537 538config X86_UV 539 bool "SGI Ultraviolet" 540 depends on X86_64 541 depends on X86_EXTENDED_PLATFORM 542 depends on NUMA 543 depends on EFI 544 depends on X86_X2APIC 545 depends on PCI 546 ---help--- 547 This option is needed in order to support SGI Ultraviolet systems. 548 If you don't have one of these, you should say N here. 549 550# Following is an alphabetically sorted list of 32 bit extended platforms 551# Please maintain the alphabetic order if and when there are additions 552 553config X86_GOLDFISH 554 bool "Goldfish (Virtual Platform)" 555 depends on X86_EXTENDED_PLATFORM 556 ---help--- 557 Enable support for the Goldfish virtual platform used primarily 558 for Android development. Unless you are building for the Android 559 Goldfish emulator say N here. 560 561config X86_INTEL_CE 562 bool "CE4100 TV platform" 563 depends on PCI 564 depends on PCI_GODIRECT 565 depends on X86_IO_APIC 566 depends on X86_32 567 depends on X86_EXTENDED_PLATFORM 568 select X86_REBOOTFIXUPS 569 select OF 570 select OF_EARLY_FLATTREE 571 ---help--- 572 Select for the Intel CE media processor (CE4100) SOC. 573 This option compiles in support for the CE4100 SOC for settop 574 boxes and media devices. 575 576config X86_INTEL_MID 577 bool "Intel MID platform support" 578 depends on X86_EXTENDED_PLATFORM 579 depends on X86_PLATFORM_DEVICES 580 depends on PCI 581 depends on X86_64 || (PCI_GOANY && X86_32) 582 depends on X86_IO_APIC 583 select SFI 584 select I2C 585 select DW_APB_TIMER 586 select APB_TIMER 587 select INTEL_SCU_IPC 588 select MFD_INTEL_MSIC 589 ---help--- 590 Select to build a kernel capable of supporting Intel MID (Mobile 591 Internet Device) platform systems which do not have the PCI legacy 592 interfaces. If you are building for a PC class system say N here. 593 594 Intel MID platforms are based on an Intel processor and chipset which 595 consume less power than most of the x86 derivatives. 596 597config X86_INTEL_QUARK 598 bool "Intel Quark platform support" 599 depends on X86_32 600 depends on X86_EXTENDED_PLATFORM 601 depends on X86_PLATFORM_DEVICES 602 depends on X86_TSC 603 depends on PCI 604 depends on PCI_GOANY 605 depends on X86_IO_APIC 606 select IOSF_MBI 607 select INTEL_IMR 608 select COMMON_CLK 609 ---help--- 610 Select to include support for Quark X1000 SoC. 611 Say Y here if you have a Quark based system such as the Arduino 612 compatible Intel Galileo. 613 614config X86_INTEL_LPSS 615 bool "Intel Low Power Subsystem Support" 616 depends on X86 && ACPI && PCI 617 select COMMON_CLK 618 select PINCTRL 619 select IOSF_MBI 620 ---help--- 621 Select to build support for Intel Low Power Subsystem such as 622 found on Intel Lynxpoint PCH. Selecting this option enables 623 things like clock tree (common clock framework) and pincontrol 624 which are needed by the LPSS peripheral drivers. 625 626config X86_AMD_PLATFORM_DEVICE 627 bool "AMD ACPI2Platform devices support" 628 depends on ACPI 629 select COMMON_CLK 630 select PINCTRL 631 ---help--- 632 Select to interpret AMD specific ACPI device to platform device 633 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 634 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 635 implemented under PINCTRL subsystem. 636 637config IOSF_MBI 638 tristate "Intel SoC IOSF Sideband support for SoC platforms" 639 depends on PCI 640 ---help--- 641 This option enables sideband register access support for Intel SoC 642 platforms. On these platforms the IOSF sideband is used in lieu of 643 MSR's for some register accesses, mostly but not limited to thermal 644 and power. Drivers may query the availability of this device to 645 determine if they need the sideband in order to work on these 646 platforms. The sideband is available on the following SoC products. 647 This list is not meant to be exclusive. 648 - BayTrail 649 - Braswell 650 - Quark 651 652 You should say Y if you are running a kernel on one of these SoC's. 653 654config IOSF_MBI_DEBUG 655 bool "Enable IOSF sideband access through debugfs" 656 depends on IOSF_MBI && DEBUG_FS 657 ---help--- 658 Select this option to expose the IOSF sideband access registers (MCR, 659 MDR, MCRX) through debugfs to write and read register information from 660 different units on the SoC. This is most useful for obtaining device 661 state information for debug and analysis. As this is a general access 662 mechanism, users of this option would have specific knowledge of the 663 device they want to access. 664 665 If you don't require the option or are in doubt, say N. 666 667config X86_RDC321X 668 bool "RDC R-321x SoC" 669 depends on X86_32 670 depends on X86_EXTENDED_PLATFORM 671 select M486 672 select X86_REBOOTFIXUPS 673 ---help--- 674 This option is needed for RDC R-321x system-on-chip, also known 675 as R-8610-(G). 676 If you don't have one of these chips, you should say N here. 677 678config X86_32_NON_STANDARD 679 bool "Support non-standard 32-bit SMP architectures" 680 depends on X86_32 && SMP 681 depends on X86_EXTENDED_PLATFORM 682 ---help--- 683 This option compiles in the bigsmp and STA2X11 default 684 subarchitectures. It is intended for a generic binary 685 kernel. If you select them all, kernel will probe it one by 686 one and will fallback to default. 687 688# Alphabetically sorted list of Non standard 32 bit platforms 689 690config X86_SUPPORTS_MEMORY_FAILURE 691 def_bool y 692 # MCE code calls memory_failure(): 693 depends on X86_MCE 694 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 695 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 696 depends on X86_64 || !SPARSEMEM 697 select ARCH_SUPPORTS_MEMORY_FAILURE 698 699config STA2X11 700 bool "STA2X11 Companion Chip Support" 701 depends on X86_32_NON_STANDARD && PCI 702 select ARCH_HAS_PHYS_TO_DMA 703 select SWIOTLB 704 select MFD_STA2X11 705 select GPIOLIB 706 ---help--- 707 This adds support for boards based on the STA2X11 IO-Hub, 708 a.k.a. "ConneXt". The chip is used in place of the standard 709 PC chipset, so all "standard" peripherals are missing. If this 710 option is selected the kernel will still be able to boot on 711 standard PC machines. 712 713config X86_32_IRIS 714 tristate "Eurobraille/Iris poweroff module" 715 depends on X86_32 716 ---help--- 717 The Iris machines from EuroBraille do not have APM or ACPI support 718 to shut themselves down properly. A special I/O sequence is 719 needed to do so, which is what this module does at 720 kernel shutdown. 721 722 This is only for Iris machines from EuroBraille. 723 724 If unused, say N. 725 726config SCHED_OMIT_FRAME_POINTER 727 def_bool y 728 prompt "Single-depth WCHAN output" 729 depends on X86 730 ---help--- 731 Calculate simpler /proc/<PID>/wchan values. If this option 732 is disabled then wchan values will recurse back to the 733 caller function. This provides more accurate wchan values, 734 at the expense of slightly more scheduling overhead. 735 736 If in doubt, say "Y". 737 738menuconfig HYPERVISOR_GUEST 739 bool "Linux guest support" 740 ---help--- 741 Say Y here to enable options for running Linux under various hyper- 742 visors. This option enables basic hypervisor detection and platform 743 setup. 744 745 If you say N, all options in this submenu will be skipped and 746 disabled, and Linux guest support won't be built in. 747 748if HYPERVISOR_GUEST 749 750config PARAVIRT 751 bool "Enable paravirtualization code" 752 ---help--- 753 This changes the kernel so it can modify itself when it is run 754 under a hypervisor, potentially improving performance significantly 755 over full virtualization. However, when run without a hypervisor 756 the kernel is theoretically slower and slightly larger. 757 758config PARAVIRT_XXL 759 bool 760 761config PARAVIRT_DEBUG 762 bool "paravirt-ops debugging" 763 depends on PARAVIRT && DEBUG_KERNEL 764 ---help--- 765 Enable to debug paravirt_ops internals. Specifically, BUG if 766 a paravirt_op is missing when it is called. 767 768config PARAVIRT_SPINLOCKS 769 bool "Paravirtualization layer for spinlocks" 770 depends on PARAVIRT && SMP 771 ---help--- 772 Paravirtualized spinlocks allow a pvops backend to replace the 773 spinlock implementation with something virtualization-friendly 774 (for example, block the virtual CPU rather than spinning). 775 776 It has a minimal impact on native kernels and gives a nice performance 777 benefit on paravirtualized KVM / Xen kernels. 778 779 If you are unsure how to answer this question, answer Y. 780 781source "arch/x86/xen/Kconfig" 782 783config KVM_GUEST 784 bool "KVM Guest support (including kvmclock)" 785 depends on PARAVIRT 786 select PARAVIRT_CLOCK 787 default y 788 ---help--- 789 This option enables various optimizations for running under the KVM 790 hypervisor. It includes a paravirtualized clock, so that instead 791 of relying on a PIT (or probably other) emulation by the 792 underlying device model, the host provides the guest with 793 timing infrastructure such as time of day, and system time 794 795config PVH 796 bool "Support for running PVH guests" 797 ---help--- 798 This option enables the PVH entry point for guest virtual machines 799 as specified in the x86/HVM direct boot ABI. 800 801config KVM_DEBUG_FS 802 bool "Enable debug information for KVM Guests in debugfs" 803 depends on KVM_GUEST && DEBUG_FS 804 ---help--- 805 This option enables collection of various statistics for KVM guest. 806 Statistics are displayed in debugfs filesystem. Enabling this option 807 may incur significant overhead. 808 809config PARAVIRT_TIME_ACCOUNTING 810 bool "Paravirtual steal time accounting" 811 depends on PARAVIRT 812 ---help--- 813 Select this option to enable fine granularity task steal time 814 accounting. Time spent executing other tasks in parallel with 815 the current vCPU is discounted from the vCPU power. To account for 816 that, there can be a small performance impact. 817 818 If in doubt, say N here. 819 820config PARAVIRT_CLOCK 821 bool 822 823config JAILHOUSE_GUEST 824 bool "Jailhouse non-root cell support" 825 depends on X86_64 && PCI 826 select X86_PM_TIMER 827 ---help--- 828 This option allows to run Linux as guest in a Jailhouse non-root 829 cell. You can leave this option disabled if you only want to start 830 Jailhouse and run Linux afterwards in the root cell. 831 832endif #HYPERVISOR_GUEST 833 834source "arch/x86/Kconfig.cpu" 835 836config HPET_TIMER 837 def_bool X86_64 838 prompt "HPET Timer Support" if X86_32 839 ---help--- 840 Use the IA-PC HPET (High Precision Event Timer) to manage 841 time in preference to the PIT and RTC, if a HPET is 842 present. 843 HPET is the next generation timer replacing legacy 8254s. 844 The HPET provides a stable time base on SMP 845 systems, unlike the TSC, but it is more expensive to access, 846 as it is off-chip. The interface used is documented 847 in the HPET spec, revision 1. 848 849 You can safely choose Y here. However, HPET will only be 850 activated if the platform and the BIOS support this feature. 851 Otherwise the 8254 will be used for timing services. 852 853 Choose N to continue using the legacy 8254 timer. 854 855config HPET_EMULATE_RTC 856 def_bool y 857 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 858 859config APB_TIMER 860 def_bool y if X86_INTEL_MID 861 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 862 select DW_APB_TIMER 863 depends on X86_INTEL_MID && SFI 864 help 865 APB timer is the replacement for 8254, HPET on X86 MID platforms. 866 The APBT provides a stable time base on SMP 867 systems, unlike the TSC, but it is more expensive to access, 868 as it is off-chip. APB timers are always running regardless of CPU 869 C states, they are used as per CPU clockevent device when possible. 870 871# Mark as expert because too many people got it wrong. 872# The code disables itself when not needed. 873config DMI 874 default y 875 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 876 bool "Enable DMI scanning" if EXPERT 877 ---help--- 878 Enabled scanning of DMI to identify machine quirks. Say Y 879 here unless you have verified that your setup is not 880 affected by entries in the DMI blacklist. Required by PNP 881 BIOS code. 882 883config GART_IOMMU 884 bool "Old AMD GART IOMMU support" 885 select IOMMU_HELPER 886 select SWIOTLB 887 depends on X86_64 && PCI && AMD_NB 888 ---help--- 889 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 890 GART based hardware IOMMUs. 891 892 The GART supports full DMA access for devices with 32-bit access 893 limitations, on systems with more than 3 GB. This is usually needed 894 for USB, sound, many IDE/SATA chipsets and some other devices. 895 896 Newer systems typically have a modern AMD IOMMU, supported via 897 the CONFIG_AMD_IOMMU=y config option. 898 899 In normal configurations this driver is only active when needed: 900 there's more than 3 GB of memory and the system contains a 901 32-bit limited device. 902 903 If unsure, say Y. 904 905config CALGARY_IOMMU 906 bool "IBM Calgary IOMMU support" 907 select IOMMU_HELPER 908 select SWIOTLB 909 depends on X86_64 && PCI 910 ---help--- 911 Support for hardware IOMMUs in IBM's xSeries x366 and x460 912 systems. Needed to run systems with more than 3GB of memory 913 properly with 32-bit PCI devices that do not support DAC 914 (Double Address Cycle). Calgary also supports bus level 915 isolation, where all DMAs pass through the IOMMU. This 916 prevents them from going anywhere except their intended 917 destination. This catches hard-to-find kernel bugs and 918 mis-behaving drivers and devices that do not use the DMA-API 919 properly to set up their DMA buffers. The IOMMU can be 920 turned off at boot time with the iommu=off parameter. 921 Normally the kernel will make the right choice by itself. 922 If unsure, say Y. 923 924config CALGARY_IOMMU_ENABLED_BY_DEFAULT 925 def_bool y 926 prompt "Should Calgary be enabled by default?" 927 depends on CALGARY_IOMMU 928 ---help--- 929 Should Calgary be enabled by default? if you choose 'y', Calgary 930 will be used (if it exists). If you choose 'n', Calgary will not be 931 used even if it exists. If you choose 'n' and would like to use 932 Calgary anyway, pass 'iommu=calgary' on the kernel command line. 933 If unsure, say Y. 934 935config MAXSMP 936 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 937 depends on X86_64 && SMP && DEBUG_KERNEL 938 select CPUMASK_OFFSTACK 939 ---help--- 940 Enable maximum number of CPUS and NUMA Nodes for this architecture. 941 If unsure, say N. 942 943# 944# The maximum number of CPUs supported: 945# 946# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 947# and which can be configured interactively in the 948# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 949# 950# The ranges are different on 32-bit and 64-bit kernels, depending on 951# hardware capabilities and scalability features of the kernel. 952# 953# ( If MAXSMP is enabled we just use the highest possible value and disable 954# interactive configuration. ) 955# 956 957config NR_CPUS_RANGE_BEGIN 958 int 959 default NR_CPUS_RANGE_END if MAXSMP 960 default 1 if !SMP 961 default 2 962 963config NR_CPUS_RANGE_END 964 int 965 depends on X86_32 966 default 64 if SMP && X86_BIGSMP 967 default 8 if SMP && !X86_BIGSMP 968 default 1 if !SMP 969 970config NR_CPUS_RANGE_END 971 int 972 depends on X86_64 973 default 8192 if SMP && ( MAXSMP || CPUMASK_OFFSTACK) 974 default 512 if SMP && (!MAXSMP && !CPUMASK_OFFSTACK) 975 default 1 if !SMP 976 977config NR_CPUS_DEFAULT 978 int 979 depends on X86_32 980 default 32 if X86_BIGSMP 981 default 8 if SMP 982 default 1 if !SMP 983 984config NR_CPUS_DEFAULT 985 int 986 depends on X86_64 987 default 8192 if MAXSMP 988 default 64 if SMP 989 default 1 if !SMP 990 991config NR_CPUS 992 int "Maximum number of CPUs" if SMP && !MAXSMP 993 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 994 default NR_CPUS_DEFAULT 995 ---help--- 996 This allows you to specify the maximum number of CPUs which this 997 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 998 supported value is 8192, otherwise the maximum value is 512. The 999 minimum value which makes sense is 2. 1000 1001 This is purely to save memory: each supported CPU adds about 8KB 1002 to the kernel image. 1003 1004config SCHED_SMT 1005 def_bool y if SMP 1006 1007config SCHED_MC 1008 def_bool y 1009 prompt "Multi-core scheduler support" 1010 depends on SMP 1011 ---help--- 1012 Multi-core scheduler support improves the CPU scheduler's decision 1013 making when dealing with multi-core CPU chips at a cost of slightly 1014 increased overhead in some places. If unsure say N here. 1015 1016config SCHED_MC_PRIO 1017 bool "CPU core priorities scheduler support" 1018 depends on SCHED_MC && CPU_SUP_INTEL 1019 select X86_INTEL_PSTATE 1020 select CPU_FREQ 1021 default y 1022 ---help--- 1023 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1024 core ordering determined at manufacturing time, which allows 1025 certain cores to reach higher turbo frequencies (when running 1026 single threaded workloads) than others. 1027 1028 Enabling this kernel feature teaches the scheduler about 1029 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1030 scheduler's CPU selection logic accordingly, so that higher 1031 overall system performance can be achieved. 1032 1033 This feature will have no effect on CPUs without this feature. 1034 1035 If unsure say Y here. 1036 1037config UP_LATE_INIT 1038 def_bool y 1039 depends on !SMP && X86_LOCAL_APIC 1040 1041config X86_UP_APIC 1042 bool "Local APIC support on uniprocessors" if !PCI_MSI 1043 default PCI_MSI 1044 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1045 ---help--- 1046 A local APIC (Advanced Programmable Interrupt Controller) is an 1047 integrated interrupt controller in the CPU. If you have a single-CPU 1048 system which has a processor with a local APIC, you can say Y here to 1049 enable and use it. If you say Y here even though your machine doesn't 1050 have a local APIC, then the kernel will still run with no slowdown at 1051 all. The local APIC supports CPU-generated self-interrupts (timer, 1052 performance counters), and the NMI watchdog which detects hard 1053 lockups. 1054 1055config X86_UP_IOAPIC 1056 bool "IO-APIC support on uniprocessors" 1057 depends on X86_UP_APIC 1058 ---help--- 1059 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1060 SMP-capable replacement for PC-style interrupt controllers. Most 1061 SMP systems and many recent uniprocessor systems have one. 1062 1063 If you have a single-CPU system with an IO-APIC, you can say Y here 1064 to use it. If you say Y here even though your machine doesn't have 1065 an IO-APIC, then the kernel will still run with no slowdown at all. 1066 1067config X86_LOCAL_APIC 1068 def_bool y 1069 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1070 select IRQ_DOMAIN_HIERARCHY 1071 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1072 1073config X86_IO_APIC 1074 def_bool y 1075 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1076 1077config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1078 bool "Reroute for broken boot IRQs" 1079 depends on X86_IO_APIC 1080 ---help--- 1081 This option enables a workaround that fixes a source of 1082 spurious interrupts. This is recommended when threaded 1083 interrupt handling is used on systems where the generation of 1084 superfluous "boot interrupts" cannot be disabled. 1085 1086 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1087 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1088 kernel does during interrupt handling). On chipsets where this 1089 boot IRQ generation cannot be disabled, this workaround keeps 1090 the original IRQ line masked so that only the equivalent "boot 1091 IRQ" is delivered to the CPUs. The workaround also tells the 1092 kernel to set up the IRQ handler on the boot IRQ line. In this 1093 way only one interrupt is delivered to the kernel. Otherwise 1094 the spurious second interrupt may cause the kernel to bring 1095 down (vital) interrupt lines. 1096 1097 Only affects "broken" chipsets. Interrupt sharing may be 1098 increased on these systems. 1099 1100config X86_MCE 1101 bool "Machine Check / overheating reporting" 1102 select GENERIC_ALLOCATOR 1103 default y 1104 ---help--- 1105 Machine Check support allows the processor to notify the 1106 kernel if it detects a problem (e.g. overheating, data corruption). 1107 The action the kernel takes depends on the severity of the problem, 1108 ranging from warning messages to halting the machine. 1109 1110config X86_MCELOG_LEGACY 1111 bool "Support for deprecated /dev/mcelog character device" 1112 depends on X86_MCE 1113 ---help--- 1114 Enable support for /dev/mcelog which is needed by the old mcelog 1115 userspace logging daemon. Consider switching to the new generation 1116 rasdaemon solution. 1117 1118config X86_MCE_INTEL 1119 def_bool y 1120 prompt "Intel MCE features" 1121 depends on X86_MCE && X86_LOCAL_APIC 1122 ---help--- 1123 Additional support for intel specific MCE features such as 1124 the thermal monitor. 1125 1126config X86_MCE_AMD 1127 def_bool y 1128 prompt "AMD MCE features" 1129 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1130 ---help--- 1131 Additional support for AMD specific MCE features such as 1132 the DRAM Error Threshold. 1133 1134config X86_ANCIENT_MCE 1135 bool "Support for old Pentium 5 / WinChip machine checks" 1136 depends on X86_32 && X86_MCE 1137 ---help--- 1138 Include support for machine check handling on old Pentium 5 or WinChip 1139 systems. These typically need to be enabled explicitly on the command 1140 line. 1141 1142config X86_MCE_THRESHOLD 1143 depends on X86_MCE_AMD || X86_MCE_INTEL 1144 def_bool y 1145 1146config X86_MCE_INJECT 1147 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1148 tristate "Machine check injector support" 1149 ---help--- 1150 Provide support for injecting machine checks for testing purposes. 1151 If you don't know what a machine check is and you don't do kernel 1152 QA it is safe to say n. 1153 1154config X86_THERMAL_VECTOR 1155 def_bool y 1156 depends on X86_MCE_INTEL 1157 1158source "arch/x86/events/Kconfig" 1159 1160config X86_LEGACY_VM86 1161 bool "Legacy VM86 support" 1162 depends on X86_32 1163 ---help--- 1164 This option allows user programs to put the CPU into V8086 1165 mode, which is an 80286-era approximation of 16-bit real mode. 1166 1167 Some very old versions of X and/or vbetool require this option 1168 for user mode setting. Similarly, DOSEMU will use it if 1169 available to accelerate real mode DOS programs. However, any 1170 recent version of DOSEMU, X, or vbetool should be fully 1171 functional even without kernel VM86 support, as they will all 1172 fall back to software emulation. Nevertheless, if you are using 1173 a 16-bit DOS program where 16-bit performance matters, vm86 1174 mode might be faster than emulation and you might want to 1175 enable this option. 1176 1177 Note that any app that works on a 64-bit kernel is unlikely to 1178 need this option, as 64-bit kernels don't, and can't, support 1179 V8086 mode. This option is also unrelated to 16-bit protected 1180 mode and is not needed to run most 16-bit programs under Wine. 1181 1182 Enabling this option increases the complexity of the kernel 1183 and slows down exception handling a tiny bit. 1184 1185 If unsure, say N here. 1186 1187config VM86 1188 bool 1189 default X86_LEGACY_VM86 1190 1191config X86_16BIT 1192 bool "Enable support for 16-bit segments" if EXPERT 1193 default y 1194 depends on MODIFY_LDT_SYSCALL 1195 ---help--- 1196 This option is required by programs like Wine to run 16-bit 1197 protected mode legacy code on x86 processors. Disabling 1198 this option saves about 300 bytes on i386, or around 6K text 1199 plus 16K runtime memory on x86-64, 1200 1201config X86_ESPFIX32 1202 def_bool y 1203 depends on X86_16BIT && X86_32 1204 1205config X86_ESPFIX64 1206 def_bool y 1207 depends on X86_16BIT && X86_64 1208 1209config X86_VSYSCALL_EMULATION 1210 bool "Enable vsyscall emulation" if EXPERT 1211 default y 1212 depends on X86_64 1213 ---help--- 1214 This enables emulation of the legacy vsyscall page. Disabling 1215 it is roughly equivalent to booting with vsyscall=none, except 1216 that it will also disable the helpful warning if a program 1217 tries to use a vsyscall. With this option set to N, offending 1218 programs will just segfault, citing addresses of the form 1219 0xffffffffff600?00. 1220 1221 This option is required by many programs built before 2013, and 1222 care should be used even with newer programs if set to N. 1223 1224 Disabling this option saves about 7K of kernel size and 1225 possibly 4K of additional runtime pagetable memory. 1226 1227config TOSHIBA 1228 tristate "Toshiba Laptop support" 1229 depends on X86_32 1230 ---help--- 1231 This adds a driver to safely access the System Management Mode of 1232 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1233 not work on models with a Phoenix BIOS. The System Management Mode 1234 is used to set the BIOS and power saving options on Toshiba portables. 1235 1236 For information on utilities to make use of this driver see the 1237 Toshiba Linux utilities web site at: 1238 <http://www.buzzard.org.uk/toshiba/>. 1239 1240 Say Y if you intend to run this kernel on a Toshiba portable. 1241 Say N otherwise. 1242 1243config I8K 1244 tristate "Dell i8k legacy laptop support" 1245 select HWMON 1246 select SENSORS_DELL_SMM 1247 ---help--- 1248 This option enables legacy /proc/i8k userspace interface in hwmon 1249 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1250 temperature and allows controlling fan speeds of Dell laptops via 1251 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1252 it reports also power and hotkey status. For fan speed control is 1253 needed userspace package i8kutils. 1254 1255 Say Y if you intend to run this kernel on old Dell laptops or want to 1256 use userspace package i8kutils. 1257 Say N otherwise. 1258 1259config X86_REBOOTFIXUPS 1260 bool "Enable X86 board specific fixups for reboot" 1261 depends on X86_32 1262 ---help--- 1263 This enables chipset and/or board specific fixups to be done 1264 in order to get reboot to work correctly. This is only needed on 1265 some combinations of hardware and BIOS. The symptom, for which 1266 this config is intended, is when reboot ends with a stalled/hung 1267 system. 1268 1269 Currently, the only fixup is for the Geode machines using 1270 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1271 1272 Say Y if you want to enable the fixup. Currently, it's safe to 1273 enable this option even if you don't need it. 1274 Say N otherwise. 1275 1276config MICROCODE 1277 bool "CPU microcode loading support" 1278 default y 1279 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1280 select FW_LOADER 1281 ---help--- 1282 If you say Y here, you will be able to update the microcode on 1283 Intel and AMD processors. The Intel support is for the IA32 family, 1284 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1285 AMD support is for families 0x10 and later. You will obviously need 1286 the actual microcode binary data itself which is not shipped with 1287 the Linux kernel. 1288 1289 The preferred method to load microcode from a detached initrd is described 1290 in Documentation/x86/microcode.txt. For that you need to enable 1291 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1292 initrd for microcode blobs. 1293 1294 In addition, you can build the microcode into the kernel. For that you 1295 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1296 config option. 1297 1298config MICROCODE_INTEL 1299 bool "Intel microcode loading support" 1300 depends on MICROCODE 1301 default MICROCODE 1302 select FW_LOADER 1303 ---help--- 1304 This options enables microcode patch loading support for Intel 1305 processors. 1306 1307 For the current Intel microcode data package go to 1308 <https://downloadcenter.intel.com> and search for 1309 'Linux Processor Microcode Data File'. 1310 1311config MICROCODE_AMD 1312 bool "AMD microcode loading support" 1313 depends on MICROCODE 1314 select FW_LOADER 1315 ---help--- 1316 If you select this option, microcode patch loading support for AMD 1317 processors will be enabled. 1318 1319config MICROCODE_OLD_INTERFACE 1320 bool "Ancient loading interface (DEPRECATED)" 1321 default n 1322 depends on MICROCODE 1323 ---help--- 1324 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1325 which was used by userspace tools like iucode_tool and microcode.ctl. 1326 It is inadequate because it runs too late to be able to properly 1327 load microcode on a machine and it needs special tools. Instead, you 1328 should've switched to the early loading method with the initrd or 1329 builtin microcode by now: Documentation/x86/microcode.txt 1330 1331config X86_MSR 1332 tristate "/dev/cpu/*/msr - Model-specific register support" 1333 ---help--- 1334 This device gives privileged processes access to the x86 1335 Model-Specific Registers (MSRs). It is a character device with 1336 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1337 MSR accesses are directed to a specific CPU on multi-processor 1338 systems. 1339 1340config X86_CPUID 1341 tristate "/dev/cpu/*/cpuid - CPU information support" 1342 ---help--- 1343 This device gives processes access to the x86 CPUID instruction to 1344 be executed on a specific processor. It is a character device 1345 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1346 /dev/cpu/31/cpuid. 1347 1348choice 1349 prompt "High Memory Support" 1350 default HIGHMEM4G 1351 depends on X86_32 1352 1353config NOHIGHMEM 1354 bool "off" 1355 ---help--- 1356 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1357 However, the address space of 32-bit x86 processors is only 4 1358 Gigabytes large. That means that, if you have a large amount of 1359 physical memory, not all of it can be "permanently mapped" by the 1360 kernel. The physical memory that's not permanently mapped is called 1361 "high memory". 1362 1363 If you are compiling a kernel which will never run on a machine with 1364 more than 1 Gigabyte total physical RAM, answer "off" here (default 1365 choice and suitable for most users). This will result in a "3GB/1GB" 1366 split: 3GB are mapped so that each process sees a 3GB virtual memory 1367 space and the remaining part of the 4GB virtual memory space is used 1368 by the kernel to permanently map as much physical memory as 1369 possible. 1370 1371 If the machine has between 1 and 4 Gigabytes physical RAM, then 1372 answer "4GB" here. 1373 1374 If more than 4 Gigabytes is used then answer "64GB" here. This 1375 selection turns Intel PAE (Physical Address Extension) mode on. 1376 PAE implements 3-level paging on IA32 processors. PAE is fully 1377 supported by Linux, PAE mode is implemented on all recent Intel 1378 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1379 then the kernel will not boot on CPUs that don't support PAE! 1380 1381 The actual amount of total physical memory will either be 1382 auto detected or can be forced by using a kernel command line option 1383 such as "mem=256M". (Try "man bootparam" or see the documentation of 1384 your boot loader (lilo or loadlin) about how to pass options to the 1385 kernel at boot time.) 1386 1387 If unsure, say "off". 1388 1389config HIGHMEM4G 1390 bool "4GB" 1391 ---help--- 1392 Select this if you have a 32-bit processor and between 1 and 4 1393 gigabytes of physical RAM. 1394 1395config HIGHMEM64G 1396 bool "64GB" 1397 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1398 select X86_PAE 1399 ---help--- 1400 Select this if you have a 32-bit processor and more than 4 1401 gigabytes of physical RAM. 1402 1403endchoice 1404 1405choice 1406 prompt "Memory split" if EXPERT 1407 default VMSPLIT_3G 1408 depends on X86_32 1409 ---help--- 1410 Select the desired split between kernel and user memory. 1411 1412 If the address range available to the kernel is less than the 1413 physical memory installed, the remaining memory will be available 1414 as "high memory". Accessing high memory is a little more costly 1415 than low memory, as it needs to be mapped into the kernel first. 1416 Note that increasing the kernel address space limits the range 1417 available to user programs, making the address space there 1418 tighter. Selecting anything other than the default 3G/1G split 1419 will also likely make your kernel incompatible with binary-only 1420 kernel modules. 1421 1422 If you are not absolutely sure what you are doing, leave this 1423 option alone! 1424 1425 config VMSPLIT_3G 1426 bool "3G/1G user/kernel split" 1427 config VMSPLIT_3G_OPT 1428 depends on !X86_PAE 1429 bool "3G/1G user/kernel split (for full 1G low memory)" 1430 config VMSPLIT_2G 1431 bool "2G/2G user/kernel split" 1432 config VMSPLIT_2G_OPT 1433 depends on !X86_PAE 1434 bool "2G/2G user/kernel split (for full 2G low memory)" 1435 config VMSPLIT_1G 1436 bool "1G/3G user/kernel split" 1437endchoice 1438 1439config PAGE_OFFSET 1440 hex 1441 default 0xB0000000 if VMSPLIT_3G_OPT 1442 default 0x80000000 if VMSPLIT_2G 1443 default 0x78000000 if VMSPLIT_2G_OPT 1444 default 0x40000000 if VMSPLIT_1G 1445 default 0xC0000000 1446 depends on X86_32 1447 1448config HIGHMEM 1449 def_bool y 1450 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1451 1452config X86_PAE 1453 bool "PAE (Physical Address Extension) Support" 1454 depends on X86_32 && !HIGHMEM4G 1455 select PHYS_ADDR_T_64BIT 1456 select SWIOTLB 1457 ---help--- 1458 PAE is required for NX support, and furthermore enables 1459 larger swapspace support for non-overcommit purposes. It 1460 has the cost of more pagetable lookup overhead, and also 1461 consumes more pagetable space per process. 1462 1463config X86_5LEVEL 1464 bool "Enable 5-level page tables support" 1465 select DYNAMIC_MEMORY_LAYOUT 1466 select SPARSEMEM_VMEMMAP 1467 depends on X86_64 1468 ---help--- 1469 5-level paging enables access to larger address space: 1470 upto 128 PiB of virtual address space and 4 PiB of 1471 physical address space. 1472 1473 It will be supported by future Intel CPUs. 1474 1475 A kernel with the option enabled can be booted on machines that 1476 support 4- or 5-level paging. 1477 1478 See Documentation/x86/x86_64/5level-paging.txt for more 1479 information. 1480 1481 Say N if unsure. 1482 1483config X86_DIRECT_GBPAGES 1484 def_bool y 1485 depends on X86_64 && !DEBUG_PAGEALLOC 1486 ---help--- 1487 Certain kernel features effectively disable kernel 1488 linear 1 GB mappings (even if the CPU otherwise 1489 supports them), so don't confuse the user by printing 1490 that we have them enabled. 1491 1492config X86_CPA_STATISTICS 1493 bool "Enable statistic for Change Page Attribute" 1494 depends on DEBUG_FS 1495 ---help--- 1496 Expose statistics about the Change Page Attribute mechanims, which 1497 helps to determine the effectiveness of preserving large and huge 1498 page mappings when mapping protections are changed. 1499 1500config ARCH_HAS_MEM_ENCRYPT 1501 def_bool y 1502 1503config AMD_MEM_ENCRYPT 1504 bool "AMD Secure Memory Encryption (SME) support" 1505 depends on X86_64 && CPU_SUP_AMD 1506 select DYNAMIC_PHYSICAL_MASK 1507 select ARCH_USE_MEMREMAP_PROT 1508 ---help--- 1509 Say yes to enable support for the encryption of system memory. 1510 This requires an AMD processor that supports Secure Memory 1511 Encryption (SME). 1512 1513config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1514 bool "Activate AMD Secure Memory Encryption (SME) by default" 1515 default y 1516 depends on AMD_MEM_ENCRYPT 1517 ---help--- 1518 Say yes to have system memory encrypted by default if running on 1519 an AMD processor that supports Secure Memory Encryption (SME). 1520 1521 If set to Y, then the encryption of system memory can be 1522 deactivated with the mem_encrypt=off command line option. 1523 1524 If set to N, then the encryption of system memory can be 1525 activated with the mem_encrypt=on command line option. 1526 1527# Common NUMA Features 1528config NUMA 1529 bool "Numa Memory Allocation and Scheduler Support" 1530 depends on SMP 1531 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1532 default y if X86_BIGSMP 1533 ---help--- 1534 Enable NUMA (Non Uniform Memory Access) support. 1535 1536 The kernel will try to allocate memory used by a CPU on the 1537 local memory controller of the CPU and add some more 1538 NUMA awareness to the kernel. 1539 1540 For 64-bit this is recommended if the system is Intel Core i7 1541 (or later), AMD Opteron, or EM64T NUMA. 1542 1543 For 32-bit this is only needed if you boot a 32-bit 1544 kernel on a 64-bit NUMA platform. 1545 1546 Otherwise, you should say N. 1547 1548config AMD_NUMA 1549 def_bool y 1550 prompt "Old style AMD Opteron NUMA detection" 1551 depends on X86_64 && NUMA && PCI 1552 ---help--- 1553 Enable AMD NUMA node topology detection. You should say Y here if 1554 you have a multi processor AMD system. This uses an old method to 1555 read the NUMA configuration directly from the builtin Northbridge 1556 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1557 which also takes priority if both are compiled in. 1558 1559config X86_64_ACPI_NUMA 1560 def_bool y 1561 prompt "ACPI NUMA detection" 1562 depends on X86_64 && NUMA && ACPI && PCI 1563 select ACPI_NUMA 1564 ---help--- 1565 Enable ACPI SRAT based node topology detection. 1566 1567# Some NUMA nodes have memory ranges that span 1568# other nodes. Even though a pfn is valid and 1569# between a node's start and end pfns, it may not 1570# reside on that node. See memmap_init_zone() 1571# for details. 1572config NODES_SPAN_OTHER_NODES 1573 def_bool y 1574 depends on X86_64_ACPI_NUMA 1575 1576config NUMA_EMU 1577 bool "NUMA emulation" 1578 depends on NUMA 1579 ---help--- 1580 Enable NUMA emulation. A flat machine will be split 1581 into virtual nodes when booted with "numa=fake=N", where N is the 1582 number of nodes. This is only useful for debugging. 1583 1584config NODES_SHIFT 1585 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1586 range 1 10 1587 default "10" if MAXSMP 1588 default "6" if X86_64 1589 default "3" 1590 depends on NEED_MULTIPLE_NODES 1591 ---help--- 1592 Specify the maximum number of NUMA Nodes available on the target 1593 system. Increases memory reserved to accommodate various tables. 1594 1595config ARCH_HAVE_MEMORY_PRESENT 1596 def_bool y 1597 depends on X86_32 && DISCONTIGMEM 1598 1599config ARCH_FLATMEM_ENABLE 1600 def_bool y 1601 depends on X86_32 && !NUMA 1602 1603config ARCH_DISCONTIGMEM_ENABLE 1604 def_bool n 1605 depends on NUMA && X86_32 1606 depends on BROKEN 1607 1608config ARCH_SPARSEMEM_ENABLE 1609 def_bool y 1610 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1611 select SPARSEMEM_STATIC if X86_32 1612 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1613 1614config ARCH_SPARSEMEM_DEFAULT 1615 def_bool X86_64 || (NUMA && X86_32) 1616 1617config ARCH_SELECT_MEMORY_MODEL 1618 def_bool y 1619 depends on ARCH_SPARSEMEM_ENABLE 1620 1621config ARCH_MEMORY_PROBE 1622 bool "Enable sysfs memory/probe interface" 1623 depends on X86_64 && MEMORY_HOTPLUG 1624 help 1625 This option enables a sysfs memory/probe interface for testing. 1626 See Documentation/memory-hotplug.txt for more information. 1627 If you are unsure how to answer this question, answer N. 1628 1629config ARCH_PROC_KCORE_TEXT 1630 def_bool y 1631 depends on X86_64 && PROC_KCORE 1632 1633config ILLEGAL_POINTER_VALUE 1634 hex 1635 default 0 if X86_32 1636 default 0xdead000000000000 if X86_64 1637 1638config X86_PMEM_LEGACY_DEVICE 1639 bool 1640 1641config X86_PMEM_LEGACY 1642 tristate "Support non-standard NVDIMMs and ADR protected memory" 1643 depends on PHYS_ADDR_T_64BIT 1644 depends on BLK_DEV 1645 select X86_PMEM_LEGACY_DEVICE 1646 select LIBNVDIMM 1647 help 1648 Treat memory marked using the non-standard e820 type of 12 as used 1649 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1650 The kernel will offer these regions to the 'pmem' driver so 1651 they can be used for persistent storage. 1652 1653 Say Y if unsure. 1654 1655config HIGHPTE 1656 bool "Allocate 3rd-level pagetables from highmem" 1657 depends on HIGHMEM 1658 ---help--- 1659 The VM uses one page table entry for each page of physical memory. 1660 For systems with a lot of RAM, this can be wasteful of precious 1661 low memory. Setting this option will put user-space page table 1662 entries in high memory. 1663 1664config X86_CHECK_BIOS_CORRUPTION 1665 bool "Check for low memory corruption" 1666 ---help--- 1667 Periodically check for memory corruption in low memory, which 1668 is suspected to be caused by BIOS. Even when enabled in the 1669 configuration, it is disabled at runtime. Enable it by 1670 setting "memory_corruption_check=1" on the kernel command 1671 line. By default it scans the low 64k of memory every 60 1672 seconds; see the memory_corruption_check_size and 1673 memory_corruption_check_period parameters in 1674 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1675 1676 When enabled with the default parameters, this option has 1677 almost no overhead, as it reserves a relatively small amount 1678 of memory and scans it infrequently. It both detects corruption 1679 and prevents it from affecting the running system. 1680 1681 It is, however, intended as a diagnostic tool; if repeatable 1682 BIOS-originated corruption always affects the same memory, 1683 you can use memmap= to prevent the kernel from using that 1684 memory. 1685 1686config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1687 bool "Set the default setting of memory_corruption_check" 1688 depends on X86_CHECK_BIOS_CORRUPTION 1689 default y 1690 ---help--- 1691 Set whether the default state of memory_corruption_check is 1692 on or off. 1693 1694config X86_RESERVE_LOW 1695 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1696 default 64 1697 range 4 640 1698 ---help--- 1699 Specify the amount of low memory to reserve for the BIOS. 1700 1701 The first page contains BIOS data structures that the kernel 1702 must not use, so that page must always be reserved. 1703 1704 By default we reserve the first 64K of physical RAM, as a 1705 number of BIOSes are known to corrupt that memory range 1706 during events such as suspend/resume or monitor cable 1707 insertion, so it must not be used by the kernel. 1708 1709 You can set this to 4 if you are absolutely sure that you 1710 trust the BIOS to get all its memory reservations and usages 1711 right. If you know your BIOS have problems beyond the 1712 default 64K area, you can set this to 640 to avoid using the 1713 entire low memory range. 1714 1715 If you have doubts about the BIOS (e.g. suspend/resume does 1716 not work or there's kernel crashes after certain hardware 1717 hotplug events) then you might want to enable 1718 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1719 typical corruption patterns. 1720 1721 Leave this to the default value of 64 if you are unsure. 1722 1723config MATH_EMULATION 1724 bool 1725 depends on MODIFY_LDT_SYSCALL 1726 prompt "Math emulation" if X86_32 1727 ---help--- 1728 Linux can emulate a math coprocessor (used for floating point 1729 operations) if you don't have one. 486DX and Pentium processors have 1730 a math coprocessor built in, 486SX and 386 do not, unless you added 1731 a 487DX or 387, respectively. (The messages during boot time can 1732 give you some hints here ["man dmesg"].) Everyone needs either a 1733 coprocessor or this emulation. 1734 1735 If you don't have a math coprocessor, you need to say Y here; if you 1736 say Y here even though you have a coprocessor, the coprocessor will 1737 be used nevertheless. (This behavior can be changed with the kernel 1738 command line option "no387", which comes handy if your coprocessor 1739 is broken. Try "man bootparam" or see the documentation of your boot 1740 loader (lilo or loadlin) about how to pass options to the kernel at 1741 boot time.) This means that it is a good idea to say Y here if you 1742 intend to use this kernel on different machines. 1743 1744 More information about the internals of the Linux math coprocessor 1745 emulation can be found in <file:arch/x86/math-emu/README>. 1746 1747 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1748 kernel, it won't hurt. 1749 1750config MTRR 1751 def_bool y 1752 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1753 ---help--- 1754 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1755 the Memory Type Range Registers (MTRRs) may be used to control 1756 processor access to memory ranges. This is most useful if you have 1757 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1758 allows bus write transfers to be combined into a larger transfer 1759 before bursting over the PCI/AGP bus. This can increase performance 1760 of image write operations 2.5 times or more. Saying Y here creates a 1761 /proc/mtrr file which may be used to manipulate your processor's 1762 MTRRs. Typically the X server should use this. 1763 1764 This code has a reasonably generic interface so that similar 1765 control registers on other processors can be easily supported 1766 as well: 1767 1768 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1769 Registers (ARRs) which provide a similar functionality to MTRRs. For 1770 these, the ARRs are used to emulate the MTRRs. 1771 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1772 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1773 write-combining. All of these processors are supported by this code 1774 and it makes sense to say Y here if you have one of them. 1775 1776 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1777 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1778 can lead to all sorts of problems, so it's good to say Y here. 1779 1780 You can safely say Y even if your machine doesn't have MTRRs, you'll 1781 just add about 9 KB to your kernel. 1782 1783 See <file:Documentation/x86/mtrr.txt> for more information. 1784 1785config MTRR_SANITIZER 1786 def_bool y 1787 prompt "MTRR cleanup support" 1788 depends on MTRR 1789 ---help--- 1790 Convert MTRR layout from continuous to discrete, so X drivers can 1791 add writeback entries. 1792 1793 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1794 The largest mtrr entry size for a continuous block can be set with 1795 mtrr_chunk_size. 1796 1797 If unsure, say Y. 1798 1799config MTRR_SANITIZER_ENABLE_DEFAULT 1800 int "MTRR cleanup enable value (0-1)" 1801 range 0 1 1802 default "0" 1803 depends on MTRR_SANITIZER 1804 ---help--- 1805 Enable mtrr cleanup default value 1806 1807config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1808 int "MTRR cleanup spare reg num (0-7)" 1809 range 0 7 1810 default "1" 1811 depends on MTRR_SANITIZER 1812 ---help--- 1813 mtrr cleanup spare entries default, it can be changed via 1814 mtrr_spare_reg_nr=N on the kernel command line. 1815 1816config X86_PAT 1817 def_bool y 1818 prompt "x86 PAT support" if EXPERT 1819 depends on MTRR 1820 ---help--- 1821 Use PAT attributes to setup page level cache control. 1822 1823 PATs are the modern equivalents of MTRRs and are much more 1824 flexible than MTRRs. 1825 1826 Say N here if you see bootup problems (boot crash, boot hang, 1827 spontaneous reboots) or a non-working video driver. 1828 1829 If unsure, say Y. 1830 1831config ARCH_USES_PG_UNCACHED 1832 def_bool y 1833 depends on X86_PAT 1834 1835config ARCH_RANDOM 1836 def_bool y 1837 prompt "x86 architectural random number generator" if EXPERT 1838 ---help--- 1839 Enable the x86 architectural RDRAND instruction 1840 (Intel Bull Mountain technology) to generate random numbers. 1841 If supported, this is a high bandwidth, cryptographically 1842 secure hardware random number generator. 1843 1844config X86_SMAP 1845 def_bool y 1846 prompt "Supervisor Mode Access Prevention" if EXPERT 1847 ---help--- 1848 Supervisor Mode Access Prevention (SMAP) is a security 1849 feature in newer Intel processors. There is a small 1850 performance cost if this enabled and turned on; there is 1851 also a small increase in the kernel size if this is enabled. 1852 1853 If unsure, say Y. 1854 1855config X86_INTEL_UMIP 1856 def_bool y 1857 depends on CPU_SUP_INTEL 1858 prompt "Intel User Mode Instruction Prevention" if EXPERT 1859 ---help--- 1860 The User Mode Instruction Prevention (UMIP) is a security 1861 feature in newer Intel processors. If enabled, a general 1862 protection fault is issued if the SGDT, SLDT, SIDT, SMSW 1863 or STR instructions are executed in user mode. These instructions 1864 unnecessarily expose information about the hardware state. 1865 1866 The vast majority of applications do not use these instructions. 1867 For the very few that do, software emulation is provided in 1868 specific cases in protected and virtual-8086 modes. Emulated 1869 results are dummy. 1870 1871config X86_INTEL_MPX 1872 prompt "Intel MPX (Memory Protection Extensions)" 1873 def_bool n 1874 # Note: only available in 64-bit mode due to VMA flags shortage 1875 depends on CPU_SUP_INTEL && X86_64 1876 select ARCH_USES_HIGH_VMA_FLAGS 1877 ---help--- 1878 MPX provides hardware features that can be used in 1879 conjunction with compiler-instrumented code to check 1880 memory references. It is designed to detect buffer 1881 overflow or underflow bugs. 1882 1883 This option enables running applications which are 1884 instrumented or otherwise use MPX. It does not use MPX 1885 itself inside the kernel or to protect the kernel 1886 against bad memory references. 1887 1888 Enabling this option will make the kernel larger: 1889 ~8k of kernel text and 36 bytes of data on a 64-bit 1890 defconfig. It adds a long to the 'mm_struct' which 1891 will increase the kernel memory overhead of each 1892 process and adds some branches to paths used during 1893 exec() and munmap(). 1894 1895 For details, see Documentation/x86/intel_mpx.txt 1896 1897 If unsure, say N. 1898 1899config X86_INTEL_MEMORY_PROTECTION_KEYS 1900 prompt "Intel Memory Protection Keys" 1901 def_bool y 1902 # Note: only available in 64-bit mode 1903 depends on CPU_SUP_INTEL && X86_64 1904 select ARCH_USES_HIGH_VMA_FLAGS 1905 select ARCH_HAS_PKEYS 1906 ---help--- 1907 Memory Protection Keys provides a mechanism for enforcing 1908 page-based protections, but without requiring modification of the 1909 page tables when an application changes protection domains. 1910 1911 For details, see Documentation/x86/protection-keys.txt 1912 1913 If unsure, say y. 1914 1915config EFI 1916 bool "EFI runtime service support" 1917 depends on ACPI 1918 select UCS2_STRING 1919 select EFI_RUNTIME_WRAPPERS 1920 ---help--- 1921 This enables the kernel to use EFI runtime services that are 1922 available (such as the EFI variable services). 1923 1924 This option is only useful on systems that have EFI firmware. 1925 In addition, you should use the latest ELILO loader available 1926 at <http://elilo.sourceforge.net> in order to take advantage 1927 of EFI runtime services. However, even with this option, the 1928 resultant kernel should continue to boot on existing non-EFI 1929 platforms. 1930 1931config EFI_STUB 1932 bool "EFI stub support" 1933 depends on EFI && !X86_USE_3DNOW 1934 select RELOCATABLE 1935 ---help--- 1936 This kernel feature allows a bzImage to be loaded directly 1937 by EFI firmware without the use of a bootloader. 1938 1939 See Documentation/efi-stub.txt for more information. 1940 1941config EFI_MIXED 1942 bool "EFI mixed-mode support" 1943 depends on EFI_STUB && X86_64 1944 ---help--- 1945 Enabling this feature allows a 64-bit kernel to be booted 1946 on a 32-bit firmware, provided that your CPU supports 64-bit 1947 mode. 1948 1949 Note that it is not possible to boot a mixed-mode enabled 1950 kernel via the EFI boot stub - a bootloader that supports 1951 the EFI handover protocol must be used. 1952 1953 If unsure, say N. 1954 1955config SECCOMP 1956 def_bool y 1957 prompt "Enable seccomp to safely compute untrusted bytecode" 1958 ---help--- 1959 This kernel feature is useful for number crunching applications 1960 that may need to compute untrusted bytecode during their 1961 execution. By using pipes or other transports made available to 1962 the process as file descriptors supporting the read/write 1963 syscalls, it's possible to isolate those applications in 1964 their own address space using seccomp. Once seccomp is 1965 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 1966 and the task is only allowed to execute a few safe syscalls 1967 defined by each seccomp mode. 1968 1969 If unsure, say Y. Only embedded should say N here. 1970 1971source "kernel/Kconfig.hz" 1972 1973config KEXEC 1974 bool "kexec system call" 1975 select KEXEC_CORE 1976 ---help--- 1977 kexec is a system call that implements the ability to shutdown your 1978 current kernel, and to start another kernel. It is like a reboot 1979 but it is independent of the system firmware. And like a reboot 1980 you can start any kernel with it, not just Linux. 1981 1982 The name comes from the similarity to the exec system call. 1983 1984 It is an ongoing process to be certain the hardware in a machine 1985 is properly shutdown, so do not be surprised if this code does not 1986 initially work for you. As of this writing the exact hardware 1987 interface is strongly in flux, so no good recommendation can be 1988 made. 1989 1990config KEXEC_FILE 1991 bool "kexec file based system call" 1992 select KEXEC_CORE 1993 select BUILD_BIN2C 1994 depends on X86_64 1995 depends on CRYPTO=y 1996 depends on CRYPTO_SHA256=y 1997 ---help--- 1998 This is new version of kexec system call. This system call is 1999 file based and takes file descriptors as system call argument 2000 for kernel and initramfs as opposed to list of segments as 2001 accepted by previous system call. 2002 2003config ARCH_HAS_KEXEC_PURGATORY 2004 def_bool KEXEC_FILE 2005 2006config KEXEC_VERIFY_SIG 2007 bool "Verify kernel signature during kexec_file_load() syscall" 2008 depends on KEXEC_FILE 2009 ---help--- 2010 This option makes kernel signature verification mandatory for 2011 the kexec_file_load() syscall. 2012 2013 In addition to that option, you need to enable signature 2014 verification for the corresponding kernel image type being 2015 loaded in order for this to work. 2016 2017config KEXEC_BZIMAGE_VERIFY_SIG 2018 bool "Enable bzImage signature verification support" 2019 depends on KEXEC_VERIFY_SIG 2020 depends on SIGNED_PE_FILE_VERIFICATION 2021 select SYSTEM_TRUSTED_KEYRING 2022 ---help--- 2023 Enable bzImage signature verification support. 2024 2025config CRASH_DUMP 2026 bool "kernel crash dumps" 2027 depends on X86_64 || (X86_32 && HIGHMEM) 2028 ---help--- 2029 Generate crash dump after being started by kexec. 2030 This should be normally only set in special crash dump kernels 2031 which are loaded in the main kernel with kexec-tools into 2032 a specially reserved region and then later executed after 2033 a crash by kdump/kexec. The crash dump kernel must be compiled 2034 to a memory address not used by the main kernel or BIOS using 2035 PHYSICAL_START, or it must be built as a relocatable image 2036 (CONFIG_RELOCATABLE=y). 2037 For more details see Documentation/kdump/kdump.txt 2038 2039config KEXEC_JUMP 2040 bool "kexec jump" 2041 depends on KEXEC && HIBERNATION 2042 ---help--- 2043 Jump between original kernel and kexeced kernel and invoke 2044 code in physical address mode via KEXEC 2045 2046config PHYSICAL_START 2047 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2048 default "0x1000000" 2049 ---help--- 2050 This gives the physical address where the kernel is loaded. 2051 2052 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2053 bzImage will decompress itself to above physical address and 2054 run from there. Otherwise, bzImage will run from the address where 2055 it has been loaded by the boot loader and will ignore above physical 2056 address. 2057 2058 In normal kdump cases one does not have to set/change this option 2059 as now bzImage can be compiled as a completely relocatable image 2060 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2061 address. This option is mainly useful for the folks who don't want 2062 to use a bzImage for capturing the crash dump and want to use a 2063 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2064 to be specifically compiled to run from a specific memory area 2065 (normally a reserved region) and this option comes handy. 2066 2067 So if you are using bzImage for capturing the crash dump, 2068 leave the value here unchanged to 0x1000000 and set 2069 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2070 for capturing the crash dump change this value to start of 2071 the reserved region. In other words, it can be set based on 2072 the "X" value as specified in the "crashkernel=YM@XM" 2073 command line boot parameter passed to the panic-ed 2074 kernel. Please take a look at Documentation/kdump/kdump.txt 2075 for more details about crash dumps. 2076 2077 Usage of bzImage for capturing the crash dump is recommended as 2078 one does not have to build two kernels. Same kernel can be used 2079 as production kernel and capture kernel. Above option should have 2080 gone away after relocatable bzImage support is introduced. But it 2081 is present because there are users out there who continue to use 2082 vmlinux for dump capture. This option should go away down the 2083 line. 2084 2085 Don't change this unless you know what you are doing. 2086 2087config RELOCATABLE 2088 bool "Build a relocatable kernel" 2089 default y 2090 ---help--- 2091 This builds a kernel image that retains relocation information 2092 so it can be loaded someplace besides the default 1MB. 2093 The relocations tend to make the kernel binary about 10% larger, 2094 but are discarded at runtime. 2095 2096 One use is for the kexec on panic case where the recovery kernel 2097 must live at a different physical address than the primary 2098 kernel. 2099 2100 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2101 it has been loaded at and the compile time physical address 2102 (CONFIG_PHYSICAL_START) is used as the minimum location. 2103 2104config RANDOMIZE_BASE 2105 bool "Randomize the address of the kernel image (KASLR)" 2106 depends on RELOCATABLE 2107 default y 2108 ---help--- 2109 In support of Kernel Address Space Layout Randomization (KASLR), 2110 this randomizes the physical address at which the kernel image 2111 is decompressed and the virtual address where the kernel 2112 image is mapped, as a security feature that deters exploit 2113 attempts relying on knowledge of the location of kernel 2114 code internals. 2115 2116 On 64-bit, the kernel physical and virtual addresses are 2117 randomized separately. The physical address will be anywhere 2118 between 16MB and the top of physical memory (up to 64TB). The 2119 virtual address will be randomized from 16MB up to 1GB (9 bits 2120 of entropy). Note that this also reduces the memory space 2121 available to kernel modules from 1.5GB to 1GB. 2122 2123 On 32-bit, the kernel physical and virtual addresses are 2124 randomized together. They will be randomized from 16MB up to 2125 512MB (8 bits of entropy). 2126 2127 Entropy is generated using the RDRAND instruction if it is 2128 supported. If RDTSC is supported, its value is mixed into 2129 the entropy pool as well. If neither RDRAND nor RDTSC are 2130 supported, then entropy is read from the i8254 timer. The 2131 usable entropy is limited by the kernel being built using 2132 2GB addressing, and that PHYSICAL_ALIGN must be at a 2133 minimum of 2MB. As a result, only 10 bits of entropy are 2134 theoretically possible, but the implementations are further 2135 limited due to memory layouts. 2136 2137 If unsure, say Y. 2138 2139# Relocation on x86 needs some additional build support 2140config X86_NEED_RELOCS 2141 def_bool y 2142 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2143 2144config PHYSICAL_ALIGN 2145 hex "Alignment value to which kernel should be aligned" 2146 default "0x200000" 2147 range 0x2000 0x1000000 if X86_32 2148 range 0x200000 0x1000000 if X86_64 2149 ---help--- 2150 This value puts the alignment restrictions on physical address 2151 where kernel is loaded and run from. Kernel is compiled for an 2152 address which meets above alignment restriction. 2153 2154 If bootloader loads the kernel at a non-aligned address and 2155 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2156 address aligned to above value and run from there. 2157 2158 If bootloader loads the kernel at a non-aligned address and 2159 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2160 load address and decompress itself to the address it has been 2161 compiled for and run from there. The address for which kernel is 2162 compiled already meets above alignment restrictions. Hence the 2163 end result is that kernel runs from a physical address meeting 2164 above alignment restrictions. 2165 2166 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2167 this value must be a multiple of 0x200000. 2168 2169 Don't change this unless you know what you are doing. 2170 2171config DYNAMIC_MEMORY_LAYOUT 2172 bool 2173 ---help--- 2174 This option makes base addresses of vmalloc and vmemmap as well as 2175 __PAGE_OFFSET movable during boot. 2176 2177config RANDOMIZE_MEMORY 2178 bool "Randomize the kernel memory sections" 2179 depends on X86_64 2180 depends on RANDOMIZE_BASE 2181 select DYNAMIC_MEMORY_LAYOUT 2182 default RANDOMIZE_BASE 2183 ---help--- 2184 Randomizes the base virtual address of kernel memory sections 2185 (physical memory mapping, vmalloc & vmemmap). This security feature 2186 makes exploits relying on predictable memory locations less reliable. 2187 2188 The order of allocations remains unchanged. Entropy is generated in 2189 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2190 configuration have in average 30,000 different possible virtual 2191 addresses for each memory section. 2192 2193 If unsure, say Y. 2194 2195config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2196 hex "Physical memory mapping padding" if EXPERT 2197 depends on RANDOMIZE_MEMORY 2198 default "0xa" if MEMORY_HOTPLUG 2199 default "0x0" 2200 range 0x1 0x40 if MEMORY_HOTPLUG 2201 range 0x0 0x40 2202 ---help--- 2203 Define the padding in terabytes added to the existing physical 2204 memory size during kernel memory randomization. It is useful 2205 for memory hotplug support but reduces the entropy available for 2206 address randomization. 2207 2208 If unsure, leave at the default value. 2209 2210config HOTPLUG_CPU 2211 def_bool y 2212 depends on SMP 2213 2214config BOOTPARAM_HOTPLUG_CPU0 2215 bool "Set default setting of cpu0_hotpluggable" 2216 depends on HOTPLUG_CPU 2217 ---help--- 2218 Set whether default state of cpu0_hotpluggable is on or off. 2219 2220 Say Y here to enable CPU0 hotplug by default. If this switch 2221 is turned on, there is no need to give cpu0_hotplug kernel 2222 parameter and the CPU0 hotplug feature is enabled by default. 2223 2224 Please note: there are two known CPU0 dependencies if you want 2225 to enable the CPU0 hotplug feature either by this switch or by 2226 cpu0_hotplug kernel parameter. 2227 2228 First, resume from hibernate or suspend always starts from CPU0. 2229 So hibernate and suspend are prevented if CPU0 is offline. 2230 2231 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2232 offline if any interrupt can not migrate out of CPU0. There may 2233 be other CPU0 dependencies. 2234 2235 Please make sure the dependencies are under your control before 2236 you enable this feature. 2237 2238 Say N if you don't want to enable CPU0 hotplug feature by default. 2239 You still can enable the CPU0 hotplug feature at boot by kernel 2240 parameter cpu0_hotplug. 2241 2242config DEBUG_HOTPLUG_CPU0 2243 def_bool n 2244 prompt "Debug CPU0 hotplug" 2245 depends on HOTPLUG_CPU 2246 ---help--- 2247 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2248 soon as possible and boots up userspace with CPU0 offlined. User 2249 can online CPU0 back after boot time. 2250 2251 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2252 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2253 compilation or giving cpu0_hotplug kernel parameter at boot. 2254 2255 If unsure, say N. 2256 2257config COMPAT_VDSO 2258 def_bool n 2259 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2260 depends on COMPAT_32 2261 ---help--- 2262 Certain buggy versions of glibc will crash if they are 2263 presented with a 32-bit vDSO that is not mapped at the address 2264 indicated in its segment table. 2265 2266 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2267 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2268 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2269 the only released version with the bug, but OpenSUSE 9 2270 contains a buggy "glibc 2.3.2". 2271 2272 The symptom of the bug is that everything crashes on startup, saying: 2273 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2274 2275 Saying Y here changes the default value of the vdso32 boot 2276 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2277 This works around the glibc bug but hurts performance. 2278 2279 If unsure, say N: if you are compiling your own kernel, you 2280 are unlikely to be using a buggy version of glibc. 2281 2282choice 2283 prompt "vsyscall table for legacy applications" 2284 depends on X86_64 2285 default LEGACY_VSYSCALL_EMULATE 2286 help 2287 Legacy user code that does not know how to find the vDSO expects 2288 to be able to issue three syscalls by calling fixed addresses in 2289 kernel space. Since this location is not randomized with ASLR, 2290 it can be used to assist security vulnerability exploitation. 2291 2292 This setting can be changed at boot time via the kernel command 2293 line parameter vsyscall=[emulate|none]. 2294 2295 On a system with recent enough glibc (2.14 or newer) and no 2296 static binaries, you can say None without a performance penalty 2297 to improve security. 2298 2299 If unsure, select "Emulate". 2300 2301 config LEGACY_VSYSCALL_EMULATE 2302 bool "Emulate" 2303 help 2304 The kernel traps and emulates calls into the fixed 2305 vsyscall address mapping. This makes the mapping 2306 non-executable, but it still contains known contents, 2307 which could be used in certain rare security vulnerability 2308 exploits. This configuration is recommended when userspace 2309 still uses the vsyscall area. 2310 2311 config LEGACY_VSYSCALL_NONE 2312 bool "None" 2313 help 2314 There will be no vsyscall mapping at all. This will 2315 eliminate any risk of ASLR bypass due to the vsyscall 2316 fixed address mapping. Attempts to use the vsyscalls 2317 will be reported to dmesg, so that either old or 2318 malicious userspace programs can be identified. 2319 2320endchoice 2321 2322config CMDLINE_BOOL 2323 bool "Built-in kernel command line" 2324 ---help--- 2325 Allow for specifying boot arguments to the kernel at 2326 build time. On some systems (e.g. embedded ones), it is 2327 necessary or convenient to provide some or all of the 2328 kernel boot arguments with the kernel itself (that is, 2329 to not rely on the boot loader to provide them.) 2330 2331 To compile command line arguments into the kernel, 2332 set this option to 'Y', then fill in the 2333 boot arguments in CONFIG_CMDLINE. 2334 2335 Systems with fully functional boot loaders (i.e. non-embedded) 2336 should leave this option set to 'N'. 2337 2338config CMDLINE 2339 string "Built-in kernel command string" 2340 depends on CMDLINE_BOOL 2341 default "" 2342 ---help--- 2343 Enter arguments here that should be compiled into the kernel 2344 image and used at boot time. If the boot loader provides a 2345 command line at boot time, it is appended to this string to 2346 form the full kernel command line, when the system boots. 2347 2348 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2349 change this behavior. 2350 2351 In most cases, the command line (whether built-in or provided 2352 by the boot loader) should specify the device for the root 2353 file system. 2354 2355config CMDLINE_OVERRIDE 2356 bool "Built-in command line overrides boot loader arguments" 2357 depends on CMDLINE_BOOL 2358 ---help--- 2359 Set this option to 'Y' to have the kernel ignore the boot loader 2360 command line, and use ONLY the built-in command line. 2361 2362 This is used to work around broken boot loaders. This should 2363 be set to 'N' under normal conditions. 2364 2365config MODIFY_LDT_SYSCALL 2366 bool "Enable the LDT (local descriptor table)" if EXPERT 2367 default y 2368 ---help--- 2369 Linux can allow user programs to install a per-process x86 2370 Local Descriptor Table (LDT) using the modify_ldt(2) system 2371 call. This is required to run 16-bit or segmented code such as 2372 DOSEMU or some Wine programs. It is also used by some very old 2373 threading libraries. 2374 2375 Enabling this feature adds a small amount of overhead to 2376 context switches and increases the low-level kernel attack 2377 surface. Disabling it removes the modify_ldt(2) system call. 2378 2379 Saying 'N' here may make sense for embedded or server kernels. 2380 2381source "kernel/livepatch/Kconfig" 2382 2383endmenu 2384 2385config ARCH_HAS_ADD_PAGES 2386 def_bool y 2387 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2388 2389config ARCH_ENABLE_MEMORY_HOTPLUG 2390 def_bool y 2391 depends on X86_64 || (X86_32 && HIGHMEM) 2392 2393config ARCH_ENABLE_MEMORY_HOTREMOVE 2394 def_bool y 2395 depends on MEMORY_HOTPLUG 2396 2397config USE_PERCPU_NUMA_NODE_ID 2398 def_bool y 2399 depends on NUMA 2400 2401config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2402 def_bool y 2403 depends on X86_64 || X86_PAE 2404 2405config ARCH_ENABLE_HUGEPAGE_MIGRATION 2406 def_bool y 2407 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2408 2409config ARCH_ENABLE_THP_MIGRATION 2410 def_bool y 2411 depends on X86_64 && TRANSPARENT_HUGEPAGE 2412 2413menu "Power management and ACPI options" 2414 2415config ARCH_HIBERNATION_HEADER 2416 def_bool y 2417 depends on HIBERNATION 2418 2419source "kernel/power/Kconfig" 2420 2421source "drivers/acpi/Kconfig" 2422 2423source "drivers/sfi/Kconfig" 2424 2425config X86_APM_BOOT 2426 def_bool y 2427 depends on APM 2428 2429menuconfig APM 2430 tristate "APM (Advanced Power Management) BIOS support" 2431 depends on X86_32 && PM_SLEEP 2432 ---help--- 2433 APM is a BIOS specification for saving power using several different 2434 techniques. This is mostly useful for battery powered laptops with 2435 APM compliant BIOSes. If you say Y here, the system time will be 2436 reset after a RESUME operation, the /proc/apm device will provide 2437 battery status information, and user-space programs will receive 2438 notification of APM "events" (e.g. battery status change). 2439 2440 If you select "Y" here, you can disable actual use of the APM 2441 BIOS by passing the "apm=off" option to the kernel at boot time. 2442 2443 Note that the APM support is almost completely disabled for 2444 machines with more than one CPU. 2445 2446 In order to use APM, you will need supporting software. For location 2447 and more information, read <file:Documentation/power/apm-acpi.txt> 2448 and the Battery Powered Linux mini-HOWTO, available from 2449 <http://www.tldp.org/docs.html#howto>. 2450 2451 This driver does not spin down disk drives (see the hdparm(8) 2452 manpage ("man 8 hdparm") for that), and it doesn't turn off 2453 VESA-compliant "green" monitors. 2454 2455 This driver does not support the TI 4000M TravelMate and the ACER 2456 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2457 desktop machines also don't have compliant BIOSes, and this driver 2458 may cause those machines to panic during the boot phase. 2459 2460 Generally, if you don't have a battery in your machine, there isn't 2461 much point in using this driver and you should say N. If you get 2462 random kernel OOPSes or reboots that don't seem to be related to 2463 anything, try disabling/enabling this option (or disabling/enabling 2464 APM in your BIOS). 2465 2466 Some other things you should try when experiencing seemingly random, 2467 "weird" problems: 2468 2469 1) make sure that you have enough swap space and that it is 2470 enabled. 2471 2) pass the "no-hlt" option to the kernel 2472 3) switch on floating point emulation in the kernel and pass 2473 the "no387" option to the kernel 2474 4) pass the "floppy=nodma" option to the kernel 2475 5) pass the "mem=4M" option to the kernel (thereby disabling 2476 all but the first 4 MB of RAM) 2477 6) make sure that the CPU is not over clocked. 2478 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2479 8) disable the cache from your BIOS settings 2480 9) install a fan for the video card or exchange video RAM 2481 10) install a better fan for the CPU 2482 11) exchange RAM chips 2483 12) exchange the motherboard. 2484 2485 To compile this driver as a module, choose M here: the 2486 module will be called apm. 2487 2488if APM 2489 2490config APM_IGNORE_USER_SUSPEND 2491 bool "Ignore USER SUSPEND" 2492 ---help--- 2493 This option will ignore USER SUSPEND requests. On machines with a 2494 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2495 series notebooks, it is necessary to say Y because of a BIOS bug. 2496 2497config APM_DO_ENABLE 2498 bool "Enable PM at boot time" 2499 ---help--- 2500 Enable APM features at boot time. From page 36 of the APM BIOS 2501 specification: "When disabled, the APM BIOS does not automatically 2502 power manage devices, enter the Standby State, enter the Suspend 2503 State, or take power saving steps in response to CPU Idle calls." 2504 This driver will make CPU Idle calls when Linux is idle (unless this 2505 feature is turned off -- see "Do CPU IDLE calls", below). This 2506 should always save battery power, but more complicated APM features 2507 will be dependent on your BIOS implementation. You may need to turn 2508 this option off if your computer hangs at boot time when using APM 2509 support, or if it beeps continuously instead of suspending. Turn 2510 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2511 T400CDT. This is off by default since most machines do fine without 2512 this feature. 2513 2514config APM_CPU_IDLE 2515 depends on CPU_IDLE 2516 bool "Make CPU Idle calls when idle" 2517 ---help--- 2518 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2519 On some machines, this can activate improved power savings, such as 2520 a slowed CPU clock rate, when the machine is idle. These idle calls 2521 are made after the idle loop has run for some length of time (e.g., 2522 333 mS). On some machines, this will cause a hang at boot time or 2523 whenever the CPU becomes idle. (On machines with more than one CPU, 2524 this option does nothing.) 2525 2526config APM_DISPLAY_BLANK 2527 bool "Enable console blanking using APM" 2528 ---help--- 2529 Enable console blanking using the APM. Some laptops can use this to 2530 turn off the LCD backlight when the screen blanker of the Linux 2531 virtual console blanks the screen. Note that this is only used by 2532 the virtual console screen blanker, and won't turn off the backlight 2533 when using the X Window system. This also doesn't have anything to 2534 do with your VESA-compliant power-saving monitor. Further, this 2535 option doesn't work for all laptops -- it might not turn off your 2536 backlight at all, or it might print a lot of errors to the console, 2537 especially if you are using gpm. 2538 2539config APM_ALLOW_INTS 2540 bool "Allow interrupts during APM BIOS calls" 2541 ---help--- 2542 Normally we disable external interrupts while we are making calls to 2543 the APM BIOS as a measure to lessen the effects of a badly behaving 2544 BIOS implementation. The BIOS should reenable interrupts if it 2545 needs to. Unfortunately, some BIOSes do not -- especially those in 2546 many of the newer IBM Thinkpads. If you experience hangs when you 2547 suspend, try setting this to Y. Otherwise, say N. 2548 2549endif # APM 2550 2551source "drivers/cpufreq/Kconfig" 2552 2553source "drivers/cpuidle/Kconfig" 2554 2555source "drivers/idle/Kconfig" 2556 2557endmenu 2558 2559 2560menu "Bus options (PCI etc.)" 2561 2562choice 2563 prompt "PCI access mode" 2564 depends on X86_32 && PCI 2565 default PCI_GOANY 2566 ---help--- 2567 On PCI systems, the BIOS can be used to detect the PCI devices and 2568 determine their configuration. However, some old PCI motherboards 2569 have BIOS bugs and may crash if this is done. Also, some embedded 2570 PCI-based systems don't have any BIOS at all. Linux can also try to 2571 detect the PCI hardware directly without using the BIOS. 2572 2573 With this option, you can specify how Linux should detect the 2574 PCI devices. If you choose "BIOS", the BIOS will be used, 2575 if you choose "Direct", the BIOS won't be used, and if you 2576 choose "MMConfig", then PCI Express MMCONFIG will be used. 2577 If you choose "Any", the kernel will try MMCONFIG, then the 2578 direct access method and falls back to the BIOS if that doesn't 2579 work. If unsure, go with the default, which is "Any". 2580 2581config PCI_GOBIOS 2582 bool "BIOS" 2583 2584config PCI_GOMMCONFIG 2585 bool "MMConfig" 2586 2587config PCI_GODIRECT 2588 bool "Direct" 2589 2590config PCI_GOOLPC 2591 bool "OLPC XO-1" 2592 depends on OLPC 2593 2594config PCI_GOANY 2595 bool "Any" 2596 2597endchoice 2598 2599config PCI_BIOS 2600 def_bool y 2601 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2602 2603# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2604config PCI_DIRECT 2605 def_bool y 2606 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2607 2608config PCI_MMCONFIG 2609 bool "Support mmconfig PCI config space access" if X86_64 2610 default y 2611 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2612 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2613 2614config PCI_OLPC 2615 def_bool y 2616 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2617 2618config PCI_XEN 2619 def_bool y 2620 depends on PCI && XEN 2621 select SWIOTLB_XEN 2622 2623config MMCONF_FAM10H 2624 def_bool y 2625 depends on X86_64 && PCI_MMCONFIG && ACPI 2626 2627config PCI_CNB20LE_QUIRK 2628 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2629 depends on PCI 2630 help 2631 Read the PCI windows out of the CNB20LE host bridge. This allows 2632 PCI hotplug to work on systems with the CNB20LE chipset which do 2633 not have ACPI. 2634 2635 There's no public spec for this chipset, and this functionality 2636 is known to be incomplete. 2637 2638 You should say N unless you know you need this. 2639 2640config ISA_BUS 2641 bool "ISA bus support on modern systems" if EXPERT 2642 help 2643 Expose ISA bus device drivers and options available for selection and 2644 configuration. Enable this option if your target machine has an ISA 2645 bus. ISA is an older system, displaced by PCI and newer bus 2646 architectures -- if your target machine is modern, it probably does 2647 not have an ISA bus. 2648 2649 If unsure, say N. 2650 2651# x86_64 have no ISA slots, but can have ISA-style DMA. 2652config ISA_DMA_API 2653 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2654 default y 2655 help 2656 Enables ISA-style DMA support for devices requiring such controllers. 2657 If unsure, say Y. 2658 2659if X86_32 2660 2661config ISA 2662 bool "ISA support" 2663 ---help--- 2664 Find out whether you have ISA slots on your motherboard. ISA is the 2665 name of a bus system, i.e. the way the CPU talks to the other stuff 2666 inside your box. Other bus systems are PCI, EISA, MicroChannel 2667 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2668 newer boards don't support it. If you have ISA, say Y, otherwise N. 2669 2670config SCx200 2671 tristate "NatSemi SCx200 support" 2672 ---help--- 2673 This provides basic support for National Semiconductor's 2674 (now AMD's) Geode processors. The driver probes for the 2675 PCI-IDs of several on-chip devices, so its a good dependency 2676 for other scx200_* drivers. 2677 2678 If compiled as a module, the driver is named scx200. 2679 2680config SCx200HR_TIMER 2681 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2682 depends on SCx200 2683 default y 2684 ---help--- 2685 This driver provides a clocksource built upon the on-chip 2686 27MHz high-resolution timer. Its also a workaround for 2687 NSC Geode SC-1100's buggy TSC, which loses time when the 2688 processor goes idle (as is done by the scheduler). The 2689 other workaround is idle=poll boot option. 2690 2691config OLPC 2692 bool "One Laptop Per Child support" 2693 depends on !X86_PAE 2694 select GPIOLIB 2695 select OF 2696 select OF_PROMTREE 2697 select IRQ_DOMAIN 2698 ---help--- 2699 Add support for detecting the unique features of the OLPC 2700 XO hardware. 2701 2702config OLPC_XO1_PM 2703 bool "OLPC XO-1 Power Management" 2704 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2705 ---help--- 2706 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2707 2708config OLPC_XO1_RTC 2709 bool "OLPC XO-1 Real Time Clock" 2710 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2711 ---help--- 2712 Add support for the XO-1 real time clock, which can be used as a 2713 programmable wakeup source. 2714 2715config OLPC_XO1_SCI 2716 bool "OLPC XO-1 SCI extras" 2717 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2718 depends on INPUT=y 2719 select POWER_SUPPLY 2720 ---help--- 2721 Add support for SCI-based features of the OLPC XO-1 laptop: 2722 - EC-driven system wakeups 2723 - Power button 2724 - Ebook switch 2725 - Lid switch 2726 - AC adapter status updates 2727 - Battery status updates 2728 2729config OLPC_XO15_SCI 2730 bool "OLPC XO-1.5 SCI extras" 2731 depends on OLPC && ACPI 2732 select POWER_SUPPLY 2733 ---help--- 2734 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2735 - EC-driven system wakeups 2736 - AC adapter status updates 2737 - Battery status updates 2738 2739config ALIX 2740 bool "PCEngines ALIX System Support (LED setup)" 2741 select GPIOLIB 2742 ---help--- 2743 This option enables system support for the PCEngines ALIX. 2744 At present this just sets up LEDs for GPIO control on 2745 ALIX2/3/6 boards. However, other system specific setup should 2746 get added here. 2747 2748 Note: You must still enable the drivers for GPIO and LED support 2749 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2750 2751 Note: You have to set alix.force=1 for boards with Award BIOS. 2752 2753config NET5501 2754 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2755 select GPIOLIB 2756 ---help--- 2757 This option enables system support for the Soekris Engineering net5501. 2758 2759config GEOS 2760 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2761 select GPIOLIB 2762 depends on DMI 2763 ---help--- 2764 This option enables system support for the Traverse Technologies GEOS. 2765 2766config TS5500 2767 bool "Technologic Systems TS-5500 platform support" 2768 depends on MELAN 2769 select CHECK_SIGNATURE 2770 select NEW_LEDS 2771 select LEDS_CLASS 2772 ---help--- 2773 This option enables system support for the Technologic Systems TS-5500. 2774 2775endif # X86_32 2776 2777config AMD_NB 2778 def_bool y 2779 depends on CPU_SUP_AMD && PCI 2780 2781config X86_SYSFB 2782 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2783 help 2784 Firmwares often provide initial graphics framebuffers so the BIOS, 2785 bootloader or kernel can show basic video-output during boot for 2786 user-guidance and debugging. Historically, x86 used the VESA BIOS 2787 Extensions and EFI-framebuffers for this, which are mostly limited 2788 to x86. 2789 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2790 framebuffers so the new generic system-framebuffer drivers can be 2791 used on x86. If the framebuffer is not compatible with the generic 2792 modes, it is advertised as fallback platform framebuffer so legacy 2793 drivers like efifb, vesafb and uvesafb can pick it up. 2794 If this option is not selected, all system framebuffers are always 2795 marked as fallback platform framebuffers as usual. 2796 2797 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2798 not be able to pick up generic system framebuffers if this option 2799 is selected. You are highly encouraged to enable simplefb as 2800 replacement if you select this option. simplefb can correctly deal 2801 with generic system framebuffers. But you should still keep vesafb 2802 and others enabled as fallback if a system framebuffer is 2803 incompatible with simplefb. 2804 2805 If unsure, say Y. 2806 2807endmenu 2808 2809 2810menu "Binary Emulations" 2811 2812config IA32_EMULATION 2813 bool "IA32 Emulation" 2814 depends on X86_64 2815 select ARCH_WANT_OLD_COMPAT_IPC 2816 select BINFMT_ELF 2817 select COMPAT_BINFMT_ELF 2818 select COMPAT_OLD_SIGACTION 2819 ---help--- 2820 Include code to run legacy 32-bit programs under a 2821 64-bit kernel. You should likely turn this on, unless you're 2822 100% sure that you don't have any 32-bit programs left. 2823 2824config IA32_AOUT 2825 tristate "IA32 a.out support" 2826 depends on IA32_EMULATION 2827 depends on BROKEN 2828 ---help--- 2829 Support old a.out binaries in the 32bit emulation. 2830 2831config X86_X32 2832 bool "x32 ABI for 64-bit mode" 2833 depends on X86_64 2834 ---help--- 2835 Include code to run binaries for the x32 native 32-bit ABI 2836 for 64-bit processors. An x32 process gets access to the 2837 full 64-bit register file and wide data path while leaving 2838 pointers at 32 bits for smaller memory footprint. 2839 2840 You will need a recent binutils (2.22 or later) with 2841 elf32_x86_64 support enabled to compile a kernel with this 2842 option set. 2843 2844config COMPAT_32 2845 def_bool y 2846 depends on IA32_EMULATION || X86_32 2847 select HAVE_UID16 2848 select OLD_SIGSUSPEND3 2849 2850config COMPAT 2851 def_bool y 2852 depends on IA32_EMULATION || X86_X32 2853 2854if COMPAT 2855config COMPAT_FOR_U64_ALIGNMENT 2856 def_bool y 2857 2858config SYSVIPC_COMPAT 2859 def_bool y 2860 depends on SYSVIPC 2861endif 2862 2863endmenu 2864 2865 2866config HAVE_ATOMIC_IOMAP 2867 def_bool y 2868 depends on X86_32 2869 2870config X86_DEV_DMA_OPS 2871 bool 2872 2873config HAVE_GENERIC_GUP 2874 def_bool y 2875 2876source "drivers/firmware/Kconfig" 2877 2878source "arch/x86/kvm/Kconfig" 2879