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 select GENERIC_VDSO_32 21 22config X86_64 23 def_bool y 24 depends on 64BIT 25 # Options that are inherently 64-bit kernel only: 26 select ARCH_HAS_GIGANTIC_PAGE 27 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 28 select ARCH_USE_CMPXCHG_LOCKREF 29 select HAVE_ARCH_SOFT_DIRTY 30 select MODULES_USE_ELF_RELA 31 select NEED_DMA_MAP_STATE 32 select SWIOTLB 33 34config FORCE_DYNAMIC_FTRACE 35 def_bool y 36 depends on X86_32 37 depends on FUNCTION_TRACER 38 select DYNAMIC_FTRACE 39 help 40 We keep the static function tracing (!DYNAMIC_FTRACE) around 41 in order to test the non static function tracing in the 42 generic code, as other architectures still use it. But we 43 only need to keep it around for x86_64. No need to keep it 44 for x86_32. For x86_32, force DYNAMIC_FTRACE. 45# 46# Arch settings 47# 48# ( Note that options that are marked 'if X86_64' could in principle be 49# ported to 32-bit as well. ) 50# 51config X86 52 def_bool y 53 # 54 # Note: keep this list sorted alphabetically 55 # 56 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 57 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 58 select ARCH_32BIT_OFF_T if X86_32 59 select ARCH_CLOCKSOURCE_INIT 60 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 61 select ARCH_HAS_DEBUG_VIRTUAL 62 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 63 select ARCH_HAS_DEVMEM_IS_ALLOWED 64 select ARCH_HAS_EARLY_DEBUG if KGDB 65 select ARCH_HAS_ELF_RANDOMIZE 66 select ARCH_HAS_FAST_MULTIPLIER 67 select ARCH_HAS_FILTER_PGPROT 68 select ARCH_HAS_FORTIFY_SOURCE 69 select ARCH_HAS_GCOV_PROFILE_ALL 70 select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION 71 select ARCH_HAS_MEM_ENCRYPT 72 select ARCH_HAS_MEMBARRIER_SYNC_CORE 73 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 74 select ARCH_HAS_PMEM_API if X86_64 75 select ARCH_HAS_PTE_DEVMAP if X86_64 76 select ARCH_HAS_PTE_SPECIAL 77 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 78 select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE 79 select ARCH_HAS_SET_MEMORY 80 select ARCH_HAS_SET_DIRECT_MAP 81 select ARCH_HAS_STRICT_KERNEL_RWX 82 select ARCH_HAS_STRICT_MODULE_RWX 83 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 84 select ARCH_HAS_SYSCALL_WRAPPER 85 select ARCH_HAS_UBSAN_SANITIZE_ALL 86 select ARCH_HAS_DEBUG_WX 87 select ARCH_HAVE_NMI_SAFE_CMPXCHG 88 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 89 select ARCH_MIGHT_HAVE_PC_PARPORT 90 select ARCH_MIGHT_HAVE_PC_SERIO 91 select ARCH_STACKWALK 92 select ARCH_SUPPORTS_ACPI 93 select ARCH_SUPPORTS_ATOMIC_RMW 94 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 95 select ARCH_USE_BUILTIN_BSWAP 96 select ARCH_USE_QUEUED_RWLOCKS 97 select ARCH_USE_QUEUED_SPINLOCKS 98 select ARCH_USE_SYM_ANNOTATIONS 99 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 100 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 101 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 102 select ARCH_WANT_HUGE_PMD_SHARE 103 select ARCH_WANTS_THP_SWAP if X86_64 104 select BUILDTIME_TABLE_SORT 105 select CLKEVT_I8253 106 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 107 select CLOCKSOURCE_WATCHDOG 108 select DCACHE_WORD_ACCESS 109 select EDAC_ATOMIC_SCRUB 110 select EDAC_SUPPORT 111 select GENERIC_CLOCKEVENTS 112 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 113 select GENERIC_CLOCKEVENTS_MIN_ADJUST 114 select GENERIC_CMOS_UPDATE 115 select GENERIC_CPU_AUTOPROBE 116 select GENERIC_CPU_VULNERABILITIES 117 select GENERIC_EARLY_IOREMAP 118 select GENERIC_ENTRY 119 select GENERIC_FIND_FIRST_BIT 120 select GENERIC_IOMAP 121 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 122 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 123 select GENERIC_IRQ_MIGRATION if SMP 124 select GENERIC_IRQ_PROBE 125 select GENERIC_IRQ_RESERVATION_MODE 126 select GENERIC_IRQ_SHOW 127 select GENERIC_PENDING_IRQ if SMP 128 select GENERIC_PTDUMP 129 select GENERIC_SMP_IDLE_THREAD 130 select GENERIC_STRNCPY_FROM_USER 131 select GENERIC_STRNLEN_USER 132 select GENERIC_TIME_VSYSCALL 133 select GENERIC_GETTIMEOFDAY 134 select GENERIC_VDSO_TIME_NS 135 select GUP_GET_PTE_LOW_HIGH if X86_PAE 136 select HARDIRQS_SW_RESEND 137 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 138 select HAVE_ACPI_APEI if ACPI 139 select HAVE_ACPI_APEI_NMI if ACPI 140 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 141 select HAVE_ARCH_AUDITSYSCALL 142 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 143 select HAVE_ARCH_JUMP_LABEL 144 select HAVE_ARCH_JUMP_LABEL_RELATIVE 145 select HAVE_ARCH_KASAN if X86_64 146 select HAVE_ARCH_KASAN_VMALLOC if X86_64 147 select HAVE_ARCH_KGDB 148 select HAVE_ARCH_MMAP_RND_BITS if MMU 149 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 150 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 151 select HAVE_ARCH_PREL32_RELOCATIONS 152 select HAVE_ARCH_SECCOMP_FILTER 153 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 154 select HAVE_ARCH_STACKLEAK 155 select HAVE_ARCH_TRACEHOOK 156 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 157 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 158 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 159 select HAVE_ARCH_VMAP_STACK if X86_64 160 select HAVE_ARCH_WITHIN_STACK_FRAMES 161 select HAVE_ASM_MODVERSIONS 162 select HAVE_CMPXCHG_DOUBLE 163 select HAVE_CMPXCHG_LOCAL 164 select HAVE_CONTEXT_TRACKING if X86_64 165 select HAVE_C_RECORDMCOUNT 166 select HAVE_DEBUG_KMEMLEAK 167 select HAVE_DMA_CONTIGUOUS 168 select HAVE_DYNAMIC_FTRACE 169 select HAVE_DYNAMIC_FTRACE_WITH_REGS 170 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 171 select HAVE_EBPF_JIT 172 select HAVE_EFFICIENT_UNALIGNED_ACCESS 173 select HAVE_EISA 174 select HAVE_EXIT_THREAD 175 select HAVE_FAST_GUP 176 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 177 select HAVE_FTRACE_MCOUNT_RECORD 178 select HAVE_FUNCTION_GRAPH_TRACER 179 select HAVE_FUNCTION_TRACER 180 select HAVE_GCC_PLUGINS 181 select HAVE_HW_BREAKPOINT 182 select HAVE_IDE 183 select HAVE_IOREMAP_PROT 184 select HAVE_IRQ_TIME_ACCOUNTING 185 select HAVE_KERNEL_BZIP2 186 select HAVE_KERNEL_GZIP 187 select HAVE_KERNEL_LZ4 188 select HAVE_KERNEL_LZMA 189 select HAVE_KERNEL_LZO 190 select HAVE_KERNEL_XZ 191 select HAVE_KERNEL_ZSTD 192 select HAVE_KPROBES 193 select HAVE_KPROBES_ON_FTRACE 194 select HAVE_FUNCTION_ERROR_INJECTION 195 select HAVE_KRETPROBES 196 select HAVE_KVM 197 select HAVE_LIVEPATCH if X86_64 198 select HAVE_MIXED_BREAKPOINTS_REGS 199 select HAVE_MOD_ARCH_SPECIFIC 200 select HAVE_MOVE_PMD 201 select HAVE_NMI 202 select HAVE_OPROFILE 203 select HAVE_OPTPROBES 204 select HAVE_PCSPKR_PLATFORM 205 select HAVE_PERF_EVENTS 206 select HAVE_PERF_EVENTS_NMI 207 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 208 select HAVE_PCI 209 select HAVE_PERF_REGS 210 select HAVE_PERF_USER_STACK_DUMP 211 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 212 select HAVE_REGS_AND_STACK_ACCESS_API 213 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 214 select HAVE_FUNCTION_ARG_ACCESS_API 215 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 216 select HAVE_STACK_VALIDATION if X86_64 217 select HAVE_RSEQ 218 select HAVE_SYSCALL_TRACEPOINTS 219 select HAVE_UNSTABLE_SCHED_CLOCK 220 select HAVE_USER_RETURN_NOTIFIER 221 select HAVE_GENERIC_VDSO 222 select HOTPLUG_SMT if SMP 223 select IRQ_FORCED_THREADING 224 select NEED_SG_DMA_LENGTH 225 select PCI_DOMAINS if PCI 226 select PCI_LOCKLESS_CONFIG if PCI 227 select PERF_EVENTS 228 select RTC_LIB 229 select RTC_MC146818_LIB 230 select SPARSE_IRQ 231 select SRCU 232 select SYSCTL_EXCEPTION_TRACE 233 select THREAD_INFO_IN_TASK 234 select USER_STACKTRACE_SUPPORT 235 select VIRT_TO_BUS 236 select HAVE_ARCH_KCSAN if X86_64 237 select X86_FEATURE_NAMES if PROC_FS 238 select PROC_PID_ARCH_STATUS if PROC_FS 239 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 240 241config INSTRUCTION_DECODER 242 def_bool y 243 depends on KPROBES || PERF_EVENTS || UPROBES 244 245config OUTPUT_FORMAT 246 string 247 default "elf32-i386" if X86_32 248 default "elf64-x86-64" if X86_64 249 250config LOCKDEP_SUPPORT 251 def_bool y 252 253config STACKTRACE_SUPPORT 254 def_bool y 255 256config MMU 257 def_bool y 258 259config ARCH_MMAP_RND_BITS_MIN 260 default 28 if 64BIT 261 default 8 262 263config ARCH_MMAP_RND_BITS_MAX 264 default 32 if 64BIT 265 default 16 266 267config ARCH_MMAP_RND_COMPAT_BITS_MIN 268 default 8 269 270config ARCH_MMAP_RND_COMPAT_BITS_MAX 271 default 16 272 273config SBUS 274 bool 275 276config GENERIC_ISA_DMA 277 def_bool y 278 depends on ISA_DMA_API 279 280config GENERIC_BUG 281 def_bool y 282 depends on BUG 283 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 284 285config GENERIC_BUG_RELATIVE_POINTERS 286 bool 287 288config ARCH_MAY_HAVE_PC_FDC 289 def_bool y 290 depends on ISA_DMA_API 291 292config GENERIC_CALIBRATE_DELAY 293 def_bool y 294 295config ARCH_HAS_CPU_RELAX 296 def_bool y 297 298config ARCH_HAS_CACHE_LINE_SIZE 299 def_bool y 300 301config ARCH_HAS_FILTER_PGPROT 302 def_bool y 303 304config HAVE_SETUP_PER_CPU_AREA 305 def_bool y 306 307config NEED_PER_CPU_EMBED_FIRST_CHUNK 308 def_bool y 309 310config NEED_PER_CPU_PAGE_FIRST_CHUNK 311 def_bool y 312 313config ARCH_HIBERNATION_POSSIBLE 314 def_bool y 315 316config ARCH_SUSPEND_POSSIBLE 317 def_bool y 318 319config ARCH_WANT_GENERAL_HUGETLB 320 def_bool y 321 322config ZONE_DMA32 323 def_bool y if X86_64 324 325config AUDIT_ARCH 326 def_bool y if X86_64 327 328config ARCH_SUPPORTS_DEBUG_PAGEALLOC 329 def_bool y 330 331config KASAN_SHADOW_OFFSET 332 hex 333 depends on KASAN 334 default 0xdffffc0000000000 335 336config HAVE_INTEL_TXT 337 def_bool y 338 depends on INTEL_IOMMU && ACPI 339 340config X86_32_SMP 341 def_bool y 342 depends on X86_32 && SMP 343 344config X86_64_SMP 345 def_bool y 346 depends on X86_64 && SMP 347 348config X86_32_LAZY_GS 349 def_bool y 350 depends on X86_32 && !STACKPROTECTOR 351 352config ARCH_SUPPORTS_UPROBES 353 def_bool y 354 355config FIX_EARLYCON_MEM 356 def_bool y 357 358config DYNAMIC_PHYSICAL_MASK 359 bool 360 361config PGTABLE_LEVELS 362 int 363 default 5 if X86_5LEVEL 364 default 4 if X86_64 365 default 3 if X86_PAE 366 default 2 367 368config CC_HAS_SANE_STACKPROTECTOR 369 bool 370 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 371 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 372 help 373 We have to make sure stack protector is unconditionally disabled if 374 the compiler produces broken code. 375 376menu "Processor type and features" 377 378config ZONE_DMA 379 bool "DMA memory allocation support" if EXPERT 380 default y 381 help 382 DMA memory allocation support allows devices with less than 32-bit 383 addressing to allocate within the first 16MB of address space. 384 Disable if no such devices will be used. 385 386 If unsure, say Y. 387 388config SMP 389 bool "Symmetric multi-processing support" 390 help 391 This enables support for systems with more than one CPU. If you have 392 a system with only one CPU, say N. If you have a system with more 393 than one CPU, say Y. 394 395 If you say N here, the kernel will run on uni- and multiprocessor 396 machines, but will use only one CPU of a multiprocessor machine. If 397 you say Y here, the kernel will run on many, but not all, 398 uniprocessor machines. On a uniprocessor machine, the kernel 399 will run faster if you say N here. 400 401 Note that if you say Y here and choose architecture "586" or 402 "Pentium" under "Processor family", the kernel will not work on 486 403 architectures. Similarly, multiprocessor kernels for the "PPro" 404 architecture may not work on all Pentium based boards. 405 406 People using multiprocessor machines who say Y here should also say 407 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 408 Management" code will be disabled if you say Y here. 409 410 See also <file:Documentation/x86/i386/IO-APIC.rst>, 411 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 412 <http://www.tldp.org/docs.html#howto>. 413 414 If you don't know what to do here, say N. 415 416config X86_FEATURE_NAMES 417 bool "Processor feature human-readable names" if EMBEDDED 418 default y 419 help 420 This option compiles in a table of x86 feature bits and corresponding 421 names. This is required to support /proc/cpuinfo and a few kernel 422 messages. You can disable this to save space, at the expense of 423 making those few kernel messages show numeric feature bits instead. 424 425 If in doubt, say Y. 426 427config X86_X2APIC 428 bool "Support x2apic" 429 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 430 help 431 This enables x2apic support on CPUs that have this feature. 432 433 This allows 32-bit apic IDs (so it can support very large systems), 434 and accesses the local apic via MSRs not via mmio. 435 436 If you don't know what to do here, say N. 437 438config X86_MPPARSE 439 bool "Enable MPS table" if ACPI || SFI 440 default y 441 depends on X86_LOCAL_APIC 442 help 443 For old smp systems that do not have proper acpi support. Newer systems 444 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 445 446config GOLDFISH 447 def_bool y 448 depends on X86_GOLDFISH 449 450config RETPOLINE 451 bool "Avoid speculative indirect branches in kernel" 452 default y 453 select STACK_VALIDATION if HAVE_STACK_VALIDATION 454 help 455 Compile kernel with the retpoline compiler options to guard against 456 kernel-to-user data leaks by avoiding speculative indirect 457 branches. Requires a compiler with -mindirect-branch=thunk-extern 458 support for full protection. The kernel may run slower. 459 460config X86_CPU_RESCTRL 461 bool "x86 CPU resource control support" 462 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 463 select KERNFS 464 select PROC_CPU_RESCTRL if PROC_FS 465 help 466 Enable x86 CPU resource control support. 467 468 Provide support for the allocation and monitoring of system resources 469 usage by the CPU. 470 471 Intel calls this Intel Resource Director Technology 472 (Intel(R) RDT). More information about RDT can be found in the 473 Intel x86 Architecture Software Developer Manual. 474 475 AMD calls this AMD Platform Quality of Service (AMD QoS). 476 More information about AMD QoS can be found in the AMD64 Technology 477 Platform Quality of Service Extensions manual. 478 479 Say N if unsure. 480 481if X86_32 482config X86_BIGSMP 483 bool "Support for big SMP systems with more than 8 CPUs" 484 depends on SMP 485 help 486 This option is needed for the systems that have more than 8 CPUs. 487 488config X86_EXTENDED_PLATFORM 489 bool "Support for extended (non-PC) x86 platforms" 490 default y 491 help 492 If you disable this option then the kernel will only support 493 standard PC platforms. (which covers the vast majority of 494 systems out there.) 495 496 If you enable this option then you'll be able to select support 497 for the following (non-PC) 32 bit x86 platforms: 498 Goldfish (Android emulator) 499 AMD Elan 500 RDC R-321x SoC 501 SGI 320/540 (Visual Workstation) 502 STA2X11-based (e.g. Northville) 503 Moorestown MID devices 504 505 If you have one of these systems, or if you want to build a 506 generic distribution kernel, say Y here - otherwise say N. 507endif 508 509if X86_64 510config X86_EXTENDED_PLATFORM 511 bool "Support for extended (non-PC) x86 platforms" 512 default y 513 help 514 If you disable this option then the kernel will only support 515 standard PC platforms. (which covers the vast majority of 516 systems out there.) 517 518 If you enable this option then you'll be able to select support 519 for the following (non-PC) 64 bit x86 platforms: 520 Numascale NumaChip 521 ScaleMP vSMP 522 SGI Ultraviolet 523 524 If you have one of these systems, or if you want to build a 525 generic distribution kernel, say Y here - otherwise say N. 526endif 527# This is an alphabetically sorted list of 64 bit extended platforms 528# Please maintain the alphabetic order if and when there are additions 529config X86_NUMACHIP 530 bool "Numascale NumaChip" 531 depends on X86_64 532 depends on X86_EXTENDED_PLATFORM 533 depends on NUMA 534 depends on SMP 535 depends on X86_X2APIC 536 depends on PCI_MMCONFIG 537 help 538 Adds support for Numascale NumaChip large-SMP systems. Needed to 539 enable more than ~168 cores. 540 If you don't have one of these, you should say N here. 541 542config X86_VSMP 543 bool "ScaleMP vSMP" 544 select HYPERVISOR_GUEST 545 select PARAVIRT 546 depends on X86_64 && PCI 547 depends on X86_EXTENDED_PLATFORM 548 depends on SMP 549 help 550 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 551 supposed to run on these EM64T-based machines. Only choose this option 552 if you have one of these machines. 553 554config X86_UV 555 bool "SGI Ultraviolet" 556 depends on X86_64 557 depends on X86_EXTENDED_PLATFORM 558 depends on NUMA 559 depends on EFI 560 depends on X86_X2APIC 561 depends on PCI 562 help 563 This option is needed in order to support SGI Ultraviolet systems. 564 If you don't have one of these, you should say N here. 565 566# Following is an alphabetically sorted list of 32 bit extended platforms 567# Please maintain the alphabetic order if and when there are additions 568 569config X86_GOLDFISH 570 bool "Goldfish (Virtual Platform)" 571 depends on X86_EXTENDED_PLATFORM 572 help 573 Enable support for the Goldfish virtual platform used primarily 574 for Android development. Unless you are building for the Android 575 Goldfish emulator say N here. 576 577config X86_INTEL_CE 578 bool "CE4100 TV platform" 579 depends on PCI 580 depends on PCI_GODIRECT 581 depends on X86_IO_APIC 582 depends on X86_32 583 depends on X86_EXTENDED_PLATFORM 584 select X86_REBOOTFIXUPS 585 select OF 586 select OF_EARLY_FLATTREE 587 help 588 Select for the Intel CE media processor (CE4100) SOC. 589 This option compiles in support for the CE4100 SOC for settop 590 boxes and media devices. 591 592config X86_INTEL_MID 593 bool "Intel MID platform support" 594 depends on X86_EXTENDED_PLATFORM 595 depends on X86_PLATFORM_DEVICES 596 depends on PCI 597 depends on X86_64 || (PCI_GOANY && X86_32) 598 depends on X86_IO_APIC 599 select SFI 600 select I2C 601 select DW_APB_TIMER 602 select APB_TIMER 603 select INTEL_SCU_PCI 604 select MFD_INTEL_MSIC 605 help 606 Select to build a kernel capable of supporting Intel MID (Mobile 607 Internet Device) platform systems which do not have the PCI legacy 608 interfaces. If you are building for a PC class system say N here. 609 610 Intel MID platforms are based on an Intel processor and chipset which 611 consume less power than most of the x86 derivatives. 612 613config X86_INTEL_QUARK 614 bool "Intel Quark platform support" 615 depends on X86_32 616 depends on X86_EXTENDED_PLATFORM 617 depends on X86_PLATFORM_DEVICES 618 depends on X86_TSC 619 depends on PCI 620 depends on PCI_GOANY 621 depends on X86_IO_APIC 622 select IOSF_MBI 623 select INTEL_IMR 624 select COMMON_CLK 625 help 626 Select to include support for Quark X1000 SoC. 627 Say Y here if you have a Quark based system such as the Arduino 628 compatible Intel Galileo. 629 630config X86_INTEL_LPSS 631 bool "Intel Low Power Subsystem Support" 632 depends on X86 && ACPI && PCI 633 select COMMON_CLK 634 select PINCTRL 635 select IOSF_MBI 636 help 637 Select to build support for Intel Low Power Subsystem such as 638 found on Intel Lynxpoint PCH. Selecting this option enables 639 things like clock tree (common clock framework) and pincontrol 640 which are needed by the LPSS peripheral drivers. 641 642config X86_AMD_PLATFORM_DEVICE 643 bool "AMD ACPI2Platform devices support" 644 depends on ACPI 645 select COMMON_CLK 646 select PINCTRL 647 help 648 Select to interpret AMD specific ACPI device to platform device 649 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 650 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 651 implemented under PINCTRL subsystem. 652 653config IOSF_MBI 654 tristate "Intel SoC IOSF Sideband support for SoC platforms" 655 depends on PCI 656 help 657 This option enables sideband register access support for Intel SoC 658 platforms. On these platforms the IOSF sideband is used in lieu of 659 MSR's for some register accesses, mostly but not limited to thermal 660 and power. Drivers may query the availability of this device to 661 determine if they need the sideband in order to work on these 662 platforms. The sideband is available on the following SoC products. 663 This list is not meant to be exclusive. 664 - BayTrail 665 - Braswell 666 - Quark 667 668 You should say Y if you are running a kernel on one of these SoC's. 669 670config IOSF_MBI_DEBUG 671 bool "Enable IOSF sideband access through debugfs" 672 depends on IOSF_MBI && DEBUG_FS 673 help 674 Select this option to expose the IOSF sideband access registers (MCR, 675 MDR, MCRX) through debugfs to write and read register information from 676 different units on the SoC. This is most useful for obtaining device 677 state information for debug and analysis. As this is a general access 678 mechanism, users of this option would have specific knowledge of the 679 device they want to access. 680 681 If you don't require the option or are in doubt, say N. 682 683config X86_RDC321X 684 bool "RDC R-321x SoC" 685 depends on X86_32 686 depends on X86_EXTENDED_PLATFORM 687 select M486 688 select X86_REBOOTFIXUPS 689 help 690 This option is needed for RDC R-321x system-on-chip, also known 691 as R-8610-(G). 692 If you don't have one of these chips, you should say N here. 693 694config X86_32_NON_STANDARD 695 bool "Support non-standard 32-bit SMP architectures" 696 depends on X86_32 && SMP 697 depends on X86_EXTENDED_PLATFORM 698 help 699 This option compiles in the bigsmp and STA2X11 default 700 subarchitectures. It is intended for a generic binary 701 kernel. If you select them all, kernel will probe it one by 702 one and will fallback to default. 703 704# Alphabetically sorted list of Non standard 32 bit platforms 705 706config X86_SUPPORTS_MEMORY_FAILURE 707 def_bool y 708 # MCE code calls memory_failure(): 709 depends on X86_MCE 710 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 711 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 712 depends on X86_64 || !SPARSEMEM 713 select ARCH_SUPPORTS_MEMORY_FAILURE 714 715config STA2X11 716 bool "STA2X11 Companion Chip Support" 717 depends on X86_32_NON_STANDARD && PCI 718 select SWIOTLB 719 select MFD_STA2X11 720 select GPIOLIB 721 help 722 This adds support for boards based on the STA2X11 IO-Hub, 723 a.k.a. "ConneXt". The chip is used in place of the standard 724 PC chipset, so all "standard" peripherals are missing. If this 725 option is selected the kernel will still be able to boot on 726 standard PC machines. 727 728config X86_32_IRIS 729 tristate "Eurobraille/Iris poweroff module" 730 depends on X86_32 731 help 732 The Iris machines from EuroBraille do not have APM or ACPI support 733 to shut themselves down properly. A special I/O sequence is 734 needed to do so, which is what this module does at 735 kernel shutdown. 736 737 This is only for Iris machines from EuroBraille. 738 739 If unused, say N. 740 741config SCHED_OMIT_FRAME_POINTER 742 def_bool y 743 prompt "Single-depth WCHAN output" 744 depends on X86 745 help 746 Calculate simpler /proc/<PID>/wchan values. If this option 747 is disabled then wchan values will recurse back to the 748 caller function. This provides more accurate wchan values, 749 at the expense of slightly more scheduling overhead. 750 751 If in doubt, say "Y". 752 753menuconfig HYPERVISOR_GUEST 754 bool "Linux guest support" 755 help 756 Say Y here to enable options for running Linux under various hyper- 757 visors. This option enables basic hypervisor detection and platform 758 setup. 759 760 If you say N, all options in this submenu will be skipped and 761 disabled, and Linux guest support won't be built in. 762 763if HYPERVISOR_GUEST 764 765config PARAVIRT 766 bool "Enable paravirtualization code" 767 help 768 This changes the kernel so it can modify itself when it is run 769 under a hypervisor, potentially improving performance significantly 770 over full virtualization. However, when run without a hypervisor 771 the kernel is theoretically slower and slightly larger. 772 773config PARAVIRT_XXL 774 bool 775 776config PARAVIRT_DEBUG 777 bool "paravirt-ops debugging" 778 depends on PARAVIRT && DEBUG_KERNEL 779 help 780 Enable to debug paravirt_ops internals. Specifically, BUG if 781 a paravirt_op is missing when it is called. 782 783config PARAVIRT_SPINLOCKS 784 bool "Paravirtualization layer for spinlocks" 785 depends on PARAVIRT && SMP 786 help 787 Paravirtualized spinlocks allow a pvops backend to replace the 788 spinlock implementation with something virtualization-friendly 789 (for example, block the virtual CPU rather than spinning). 790 791 It has a minimal impact on native kernels and gives a nice performance 792 benefit on paravirtualized KVM / Xen kernels. 793 794 If you are unsure how to answer this question, answer Y. 795 796config X86_HV_CALLBACK_VECTOR 797 def_bool n 798 799source "arch/x86/xen/Kconfig" 800 801config KVM_GUEST 802 bool "KVM Guest support (including kvmclock)" 803 depends on PARAVIRT 804 select PARAVIRT_CLOCK 805 select ARCH_CPUIDLE_HALTPOLL 806 default y 807 help 808 This option enables various optimizations for running under the KVM 809 hypervisor. It includes a paravirtualized clock, so that instead 810 of relying on a PIT (or probably other) emulation by the 811 underlying device model, the host provides the guest with 812 timing infrastructure such as time of day, and system time 813 814config ARCH_CPUIDLE_HALTPOLL 815 def_bool n 816 prompt "Disable host haltpoll when loading haltpoll driver" 817 help 818 If virtualized under KVM, disable host haltpoll. 819 820config PVH 821 bool "Support for running PVH guests" 822 help 823 This option enables the PVH entry point for guest virtual machines 824 as specified in the x86/HVM direct boot ABI. 825 826config PARAVIRT_TIME_ACCOUNTING 827 bool "Paravirtual steal time accounting" 828 depends on PARAVIRT 829 help 830 Select this option to enable fine granularity task steal time 831 accounting. Time spent executing other tasks in parallel with 832 the current vCPU is discounted from the vCPU power. To account for 833 that, there can be a small performance impact. 834 835 If in doubt, say N here. 836 837config PARAVIRT_CLOCK 838 bool 839 840config JAILHOUSE_GUEST 841 bool "Jailhouse non-root cell support" 842 depends on X86_64 && PCI 843 select X86_PM_TIMER 844 help 845 This option allows to run Linux as guest in a Jailhouse non-root 846 cell. You can leave this option disabled if you only want to start 847 Jailhouse and run Linux afterwards in the root cell. 848 849config ACRN_GUEST 850 bool "ACRN Guest support" 851 depends on X86_64 852 select X86_HV_CALLBACK_VECTOR 853 help 854 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 855 a flexible, lightweight reference open-source hypervisor, built with 856 real-time and safety-criticality in mind. It is built for embedded 857 IOT with small footprint and real-time features. More details can be 858 found in https://projectacrn.org/. 859 860endif #HYPERVISOR_GUEST 861 862source "arch/x86/Kconfig.cpu" 863 864config HPET_TIMER 865 def_bool X86_64 866 prompt "HPET Timer Support" if X86_32 867 help 868 Use the IA-PC HPET (High Precision Event Timer) to manage 869 time in preference to the PIT and RTC, if a HPET is 870 present. 871 HPET is the next generation timer replacing legacy 8254s. 872 The HPET provides a stable time base on SMP 873 systems, unlike the TSC, but it is more expensive to access, 874 as it is off-chip. The interface used is documented 875 in the HPET spec, revision 1. 876 877 You can safely choose Y here. However, HPET will only be 878 activated if the platform and the BIOS support this feature. 879 Otherwise the 8254 will be used for timing services. 880 881 Choose N to continue using the legacy 8254 timer. 882 883config HPET_EMULATE_RTC 884 def_bool y 885 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 886 887config APB_TIMER 888 def_bool y if X86_INTEL_MID 889 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 890 select DW_APB_TIMER 891 depends on X86_INTEL_MID && SFI 892 help 893 APB timer is the replacement for 8254, HPET on X86 MID platforms. 894 The APBT provides a stable time base on SMP 895 systems, unlike the TSC, but it is more expensive to access, 896 as it is off-chip. APB timers are always running regardless of CPU 897 C states, they are used as per CPU clockevent device when possible. 898 899# Mark as expert because too many people got it wrong. 900# The code disables itself when not needed. 901config DMI 902 default y 903 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 904 bool "Enable DMI scanning" if EXPERT 905 help 906 Enabled scanning of DMI to identify machine quirks. Say Y 907 here unless you have verified that your setup is not 908 affected by entries in the DMI blacklist. Required by PNP 909 BIOS code. 910 911config GART_IOMMU 912 bool "Old AMD GART IOMMU support" 913 select DMA_OPS 914 select IOMMU_HELPER 915 select SWIOTLB 916 depends on X86_64 && PCI && AMD_NB 917 help 918 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 919 GART based hardware IOMMUs. 920 921 The GART supports full DMA access for devices with 32-bit access 922 limitations, on systems with more than 3 GB. This is usually needed 923 for USB, sound, many IDE/SATA chipsets and some other devices. 924 925 Newer systems typically have a modern AMD IOMMU, supported via 926 the CONFIG_AMD_IOMMU=y config option. 927 928 In normal configurations this driver is only active when needed: 929 there's more than 3 GB of memory and the system contains a 930 32-bit limited device. 931 932 If unsure, say Y. 933 934config MAXSMP 935 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 936 depends on X86_64 && SMP && DEBUG_KERNEL 937 select CPUMASK_OFFSTACK 938 help 939 Enable maximum number of CPUS and NUMA Nodes for this architecture. 940 If unsure, say N. 941 942# 943# The maximum number of CPUs supported: 944# 945# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 946# and which can be configured interactively in the 947# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 948# 949# The ranges are different on 32-bit and 64-bit kernels, depending on 950# hardware capabilities and scalability features of the kernel. 951# 952# ( If MAXSMP is enabled we just use the highest possible value and disable 953# interactive configuration. ) 954# 955 956config NR_CPUS_RANGE_BEGIN 957 int 958 default NR_CPUS_RANGE_END if MAXSMP 959 default 1 if !SMP 960 default 2 961 962config NR_CPUS_RANGE_END 963 int 964 depends on X86_32 965 default 64 if SMP && X86_BIGSMP 966 default 8 if SMP && !X86_BIGSMP 967 default 1 if !SMP 968 969config NR_CPUS_RANGE_END 970 int 971 depends on X86_64 972 default 8192 if SMP && CPUMASK_OFFSTACK 973 default 512 if SMP && !CPUMASK_OFFSTACK 974 default 1 if !SMP 975 976config NR_CPUS_DEFAULT 977 int 978 depends on X86_32 979 default 32 if X86_BIGSMP 980 default 8 if SMP 981 default 1 if !SMP 982 983config NR_CPUS_DEFAULT 984 int 985 depends on X86_64 986 default 8192 if MAXSMP 987 default 64 if SMP 988 default 1 if !SMP 989 990config NR_CPUS 991 int "Maximum number of CPUs" if SMP && !MAXSMP 992 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 993 default NR_CPUS_DEFAULT 994 help 995 This allows you to specify the maximum number of CPUs which this 996 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 997 supported value is 8192, otherwise the maximum value is 512. The 998 minimum value which makes sense is 2. 999 1000 This is purely to save memory: each supported CPU adds about 8KB 1001 to the kernel image. 1002 1003config SCHED_SMT 1004 def_bool y if SMP 1005 1006config SCHED_MC 1007 def_bool y 1008 prompt "Multi-core scheduler support" 1009 depends on SMP 1010 help 1011 Multi-core scheduler support improves the CPU scheduler's decision 1012 making when dealing with multi-core CPU chips at a cost of slightly 1013 increased overhead in some places. If unsure say N here. 1014 1015config SCHED_MC_PRIO 1016 bool "CPU core priorities scheduler support" 1017 depends on SCHED_MC && CPU_SUP_INTEL 1018 select X86_INTEL_PSTATE 1019 select CPU_FREQ 1020 default y 1021 help 1022 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1023 core ordering determined at manufacturing time, which allows 1024 certain cores to reach higher turbo frequencies (when running 1025 single threaded workloads) than others. 1026 1027 Enabling this kernel feature teaches the scheduler about 1028 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1029 scheduler's CPU selection logic accordingly, so that higher 1030 overall system performance can be achieved. 1031 1032 This feature will have no effect on CPUs without this feature. 1033 1034 If unsure say Y here. 1035 1036config UP_LATE_INIT 1037 def_bool y 1038 depends on !SMP && X86_LOCAL_APIC 1039 1040config X86_UP_APIC 1041 bool "Local APIC support on uniprocessors" if !PCI_MSI 1042 default PCI_MSI 1043 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1044 help 1045 A local APIC (Advanced Programmable Interrupt Controller) is an 1046 integrated interrupt controller in the CPU. If you have a single-CPU 1047 system which has a processor with a local APIC, you can say Y here to 1048 enable and use it. If you say Y here even though your machine doesn't 1049 have a local APIC, then the kernel will still run with no slowdown at 1050 all. The local APIC supports CPU-generated self-interrupts (timer, 1051 performance counters), and the NMI watchdog which detects hard 1052 lockups. 1053 1054config X86_UP_IOAPIC 1055 bool "IO-APIC support on uniprocessors" 1056 depends on X86_UP_APIC 1057 help 1058 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1059 SMP-capable replacement for PC-style interrupt controllers. Most 1060 SMP systems and many recent uniprocessor systems have one. 1061 1062 If you have a single-CPU system with an IO-APIC, you can say Y here 1063 to use it. If you say Y here even though your machine doesn't have 1064 an IO-APIC, then the kernel will still run with no slowdown at all. 1065 1066config X86_LOCAL_APIC 1067 def_bool y 1068 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1069 select IRQ_DOMAIN_HIERARCHY 1070 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1071 1072config X86_IO_APIC 1073 def_bool y 1074 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1075 1076config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1077 bool "Reroute for broken boot IRQs" 1078 depends on X86_IO_APIC 1079 help 1080 This option enables a workaround that fixes a source of 1081 spurious interrupts. This is recommended when threaded 1082 interrupt handling is used on systems where the generation of 1083 superfluous "boot interrupts" cannot be disabled. 1084 1085 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1086 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1087 kernel does during interrupt handling). On chipsets where this 1088 boot IRQ generation cannot be disabled, this workaround keeps 1089 the original IRQ line masked so that only the equivalent "boot 1090 IRQ" is delivered to the CPUs. The workaround also tells the 1091 kernel to set up the IRQ handler on the boot IRQ line. In this 1092 way only one interrupt is delivered to the kernel. Otherwise 1093 the spurious second interrupt may cause the kernel to bring 1094 down (vital) interrupt lines. 1095 1096 Only affects "broken" chipsets. Interrupt sharing may be 1097 increased on these systems. 1098 1099config X86_MCE 1100 bool "Machine Check / overheating reporting" 1101 select GENERIC_ALLOCATOR 1102 default y 1103 help 1104 Machine Check support allows the processor to notify the 1105 kernel if it detects a problem (e.g. overheating, data corruption). 1106 The action the kernel takes depends on the severity of the problem, 1107 ranging from warning messages to halting the machine. 1108 1109config X86_MCELOG_LEGACY 1110 bool "Support for deprecated /dev/mcelog character device" 1111 depends on X86_MCE 1112 help 1113 Enable support for /dev/mcelog which is needed by the old mcelog 1114 userspace logging daemon. Consider switching to the new generation 1115 rasdaemon solution. 1116 1117config X86_MCE_INTEL 1118 def_bool y 1119 prompt "Intel MCE features" 1120 depends on X86_MCE && X86_LOCAL_APIC 1121 help 1122 Additional support for intel specific MCE features such as 1123 the thermal monitor. 1124 1125config X86_MCE_AMD 1126 def_bool y 1127 prompt "AMD MCE features" 1128 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1129 help 1130 Additional support for AMD specific MCE features such as 1131 the DRAM Error Threshold. 1132 1133config X86_ANCIENT_MCE 1134 bool "Support for old Pentium 5 / WinChip machine checks" 1135 depends on X86_32 && X86_MCE 1136 help 1137 Include support for machine check handling on old Pentium 5 or WinChip 1138 systems. These typically need to be enabled explicitly on the command 1139 line. 1140 1141config X86_MCE_THRESHOLD 1142 depends on X86_MCE_AMD || X86_MCE_INTEL 1143 def_bool y 1144 1145config X86_MCE_INJECT 1146 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1147 tristate "Machine check injector support" 1148 help 1149 Provide support for injecting machine checks for testing purposes. 1150 If you don't know what a machine check is and you don't do kernel 1151 QA it is safe to say n. 1152 1153config X86_THERMAL_VECTOR 1154 def_bool y 1155 depends on X86_MCE_INTEL 1156 1157source "arch/x86/events/Kconfig" 1158 1159config X86_LEGACY_VM86 1160 bool "Legacy VM86 support" 1161 depends on X86_32 1162 help 1163 This option allows user programs to put the CPU into V8086 1164 mode, which is an 80286-era approximation of 16-bit real mode. 1165 1166 Some very old versions of X and/or vbetool require this option 1167 for user mode setting. Similarly, DOSEMU will use it if 1168 available to accelerate real mode DOS programs. However, any 1169 recent version of DOSEMU, X, or vbetool should be fully 1170 functional even without kernel VM86 support, as they will all 1171 fall back to software emulation. Nevertheless, if you are using 1172 a 16-bit DOS program where 16-bit performance matters, vm86 1173 mode might be faster than emulation and you might want to 1174 enable this option. 1175 1176 Note that any app that works on a 64-bit kernel is unlikely to 1177 need this option, as 64-bit kernels don't, and can't, support 1178 V8086 mode. This option is also unrelated to 16-bit protected 1179 mode and is not needed to run most 16-bit programs under Wine. 1180 1181 Enabling this option increases the complexity of the kernel 1182 and slows down exception handling a tiny bit. 1183 1184 If unsure, say N here. 1185 1186config VM86 1187 bool 1188 default X86_LEGACY_VM86 1189 1190config X86_16BIT 1191 bool "Enable support for 16-bit segments" if EXPERT 1192 default y 1193 depends on MODIFY_LDT_SYSCALL 1194 help 1195 This option is required by programs like Wine to run 16-bit 1196 protected mode legacy code on x86 processors. Disabling 1197 this option saves about 300 bytes on i386, or around 6K text 1198 plus 16K runtime memory on x86-64, 1199 1200config X86_ESPFIX32 1201 def_bool y 1202 depends on X86_16BIT && X86_32 1203 1204config X86_ESPFIX64 1205 def_bool y 1206 depends on X86_16BIT && X86_64 1207 1208config X86_VSYSCALL_EMULATION 1209 bool "Enable vsyscall emulation" if EXPERT 1210 default y 1211 depends on X86_64 1212 help 1213 This enables emulation of the legacy vsyscall page. Disabling 1214 it is roughly equivalent to booting with vsyscall=none, except 1215 that it will also disable the helpful warning if a program 1216 tries to use a vsyscall. With this option set to N, offending 1217 programs will just segfault, citing addresses of the form 1218 0xffffffffff600?00. 1219 1220 This option is required by many programs built before 2013, and 1221 care should be used even with newer programs if set to N. 1222 1223 Disabling this option saves about 7K of kernel size and 1224 possibly 4K of additional runtime pagetable memory. 1225 1226config X86_IOPL_IOPERM 1227 bool "IOPERM and IOPL Emulation" 1228 default y 1229 help 1230 This enables the ioperm() and iopl() syscalls which are necessary 1231 for legacy applications. 1232 1233 Legacy IOPL support is an overbroad mechanism which allows user 1234 space aside of accessing all 65536 I/O ports also to disable 1235 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1236 capabilities and permission from potentially active security 1237 modules. 1238 1239 The emulation restricts the functionality of the syscall to 1240 only allowing the full range I/O port access, but prevents the 1241 ability to disable interrupts from user space which would be 1242 granted if the hardware IOPL mechanism would be used. 1243 1244config TOSHIBA 1245 tristate "Toshiba Laptop support" 1246 depends on X86_32 1247 help 1248 This adds a driver to safely access the System Management Mode of 1249 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1250 not work on models with a Phoenix BIOS. The System Management Mode 1251 is used to set the BIOS and power saving options on Toshiba portables. 1252 1253 For information on utilities to make use of this driver see the 1254 Toshiba Linux utilities web site at: 1255 <http://www.buzzard.org.uk/toshiba/>. 1256 1257 Say Y if you intend to run this kernel on a Toshiba portable. 1258 Say N otherwise. 1259 1260config I8K 1261 tristate "Dell i8k legacy laptop support" 1262 select HWMON 1263 select SENSORS_DELL_SMM 1264 help 1265 This option enables legacy /proc/i8k userspace interface in hwmon 1266 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1267 temperature and allows controlling fan speeds of Dell laptops via 1268 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1269 it reports also power and hotkey status. For fan speed control is 1270 needed userspace package i8kutils. 1271 1272 Say Y if you intend to run this kernel on old Dell laptops or want to 1273 use userspace package i8kutils. 1274 Say N otherwise. 1275 1276config X86_REBOOTFIXUPS 1277 bool "Enable X86 board specific fixups for reboot" 1278 depends on X86_32 1279 help 1280 This enables chipset and/or board specific fixups to be done 1281 in order to get reboot to work correctly. This is only needed on 1282 some combinations of hardware and BIOS. The symptom, for which 1283 this config is intended, is when reboot ends with a stalled/hung 1284 system. 1285 1286 Currently, the only fixup is for the Geode machines using 1287 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1288 1289 Say Y if you want to enable the fixup. Currently, it's safe to 1290 enable this option even if you don't need it. 1291 Say N otherwise. 1292 1293config MICROCODE 1294 bool "CPU microcode loading support" 1295 default y 1296 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1297 help 1298 If you say Y here, you will be able to update the microcode on 1299 Intel and AMD processors. The Intel support is for the IA32 family, 1300 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1301 AMD support is for families 0x10 and later. You will obviously need 1302 the actual microcode binary data itself which is not shipped with 1303 the Linux kernel. 1304 1305 The preferred method to load microcode from a detached initrd is described 1306 in Documentation/x86/microcode.rst. For that you need to enable 1307 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1308 initrd for microcode blobs. 1309 1310 In addition, you can build the microcode into the kernel. For that you 1311 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1312 config option. 1313 1314config MICROCODE_INTEL 1315 bool "Intel microcode loading support" 1316 depends on MICROCODE 1317 default MICROCODE 1318 help 1319 This options enables microcode patch loading support for Intel 1320 processors. 1321 1322 For the current Intel microcode data package go to 1323 <https://downloadcenter.intel.com> and search for 1324 'Linux Processor Microcode Data File'. 1325 1326config MICROCODE_AMD 1327 bool "AMD microcode loading support" 1328 depends on MICROCODE 1329 help 1330 If you select this option, microcode patch loading support for AMD 1331 processors will be enabled. 1332 1333config MICROCODE_OLD_INTERFACE 1334 bool "Ancient loading interface (DEPRECATED)" 1335 default n 1336 depends on MICROCODE 1337 help 1338 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1339 which was used by userspace tools like iucode_tool and microcode.ctl. 1340 It is inadequate because it runs too late to be able to properly 1341 load microcode on a machine and it needs special tools. Instead, you 1342 should've switched to the early loading method with the initrd or 1343 builtin microcode by now: Documentation/x86/microcode.rst 1344 1345config X86_MSR 1346 tristate "/dev/cpu/*/msr - Model-specific register support" 1347 help 1348 This device gives privileged processes access to the x86 1349 Model-Specific Registers (MSRs). It is a character device with 1350 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1351 MSR accesses are directed to a specific CPU on multi-processor 1352 systems. 1353 1354config X86_CPUID 1355 tristate "/dev/cpu/*/cpuid - CPU information support" 1356 help 1357 This device gives processes access to the x86 CPUID instruction to 1358 be executed on a specific processor. It is a character device 1359 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1360 /dev/cpu/31/cpuid. 1361 1362choice 1363 prompt "High Memory Support" 1364 default HIGHMEM4G 1365 depends on X86_32 1366 1367config NOHIGHMEM 1368 bool "off" 1369 help 1370 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1371 However, the address space of 32-bit x86 processors is only 4 1372 Gigabytes large. That means that, if you have a large amount of 1373 physical memory, not all of it can be "permanently mapped" by the 1374 kernel. The physical memory that's not permanently mapped is called 1375 "high memory". 1376 1377 If you are compiling a kernel which will never run on a machine with 1378 more than 1 Gigabyte total physical RAM, answer "off" here (default 1379 choice and suitable for most users). This will result in a "3GB/1GB" 1380 split: 3GB are mapped so that each process sees a 3GB virtual memory 1381 space and the remaining part of the 4GB virtual memory space is used 1382 by the kernel to permanently map as much physical memory as 1383 possible. 1384 1385 If the machine has between 1 and 4 Gigabytes physical RAM, then 1386 answer "4GB" here. 1387 1388 If more than 4 Gigabytes is used then answer "64GB" here. This 1389 selection turns Intel PAE (Physical Address Extension) mode on. 1390 PAE implements 3-level paging on IA32 processors. PAE is fully 1391 supported by Linux, PAE mode is implemented on all recent Intel 1392 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1393 then the kernel will not boot on CPUs that don't support PAE! 1394 1395 The actual amount of total physical memory will either be 1396 auto detected or can be forced by using a kernel command line option 1397 such as "mem=256M". (Try "man bootparam" or see the documentation of 1398 your boot loader (lilo or loadlin) about how to pass options to the 1399 kernel at boot time.) 1400 1401 If unsure, say "off". 1402 1403config HIGHMEM4G 1404 bool "4GB" 1405 help 1406 Select this if you have a 32-bit processor and between 1 and 4 1407 gigabytes of physical RAM. 1408 1409config HIGHMEM64G 1410 bool "64GB" 1411 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1412 select X86_PAE 1413 help 1414 Select this if you have a 32-bit processor and more than 4 1415 gigabytes of physical RAM. 1416 1417endchoice 1418 1419choice 1420 prompt "Memory split" if EXPERT 1421 default VMSPLIT_3G 1422 depends on X86_32 1423 help 1424 Select the desired split between kernel and user memory. 1425 1426 If the address range available to the kernel is less than the 1427 physical memory installed, the remaining memory will be available 1428 as "high memory". Accessing high memory is a little more costly 1429 than low memory, as it needs to be mapped into the kernel first. 1430 Note that increasing the kernel address space limits the range 1431 available to user programs, making the address space there 1432 tighter. Selecting anything other than the default 3G/1G split 1433 will also likely make your kernel incompatible with binary-only 1434 kernel modules. 1435 1436 If you are not absolutely sure what you are doing, leave this 1437 option alone! 1438 1439 config VMSPLIT_3G 1440 bool "3G/1G user/kernel split" 1441 config VMSPLIT_3G_OPT 1442 depends on !X86_PAE 1443 bool "3G/1G user/kernel split (for full 1G low memory)" 1444 config VMSPLIT_2G 1445 bool "2G/2G user/kernel split" 1446 config VMSPLIT_2G_OPT 1447 depends on !X86_PAE 1448 bool "2G/2G user/kernel split (for full 2G low memory)" 1449 config VMSPLIT_1G 1450 bool "1G/3G user/kernel split" 1451endchoice 1452 1453config PAGE_OFFSET 1454 hex 1455 default 0xB0000000 if VMSPLIT_3G_OPT 1456 default 0x80000000 if VMSPLIT_2G 1457 default 0x78000000 if VMSPLIT_2G_OPT 1458 default 0x40000000 if VMSPLIT_1G 1459 default 0xC0000000 1460 depends on X86_32 1461 1462config HIGHMEM 1463 def_bool y 1464 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1465 1466config X86_PAE 1467 bool "PAE (Physical Address Extension) Support" 1468 depends on X86_32 && !HIGHMEM4G 1469 select PHYS_ADDR_T_64BIT 1470 select SWIOTLB 1471 help 1472 PAE is required for NX support, and furthermore enables 1473 larger swapspace support for non-overcommit purposes. It 1474 has the cost of more pagetable lookup overhead, and also 1475 consumes more pagetable space per process. 1476 1477config X86_5LEVEL 1478 bool "Enable 5-level page tables support" 1479 default y 1480 select DYNAMIC_MEMORY_LAYOUT 1481 select SPARSEMEM_VMEMMAP 1482 depends on X86_64 1483 help 1484 5-level paging enables access to larger address space: 1485 upto 128 PiB of virtual address space and 4 PiB of 1486 physical address space. 1487 1488 It will be supported by future Intel CPUs. 1489 1490 A kernel with the option enabled can be booted on machines that 1491 support 4- or 5-level paging. 1492 1493 See Documentation/x86/x86_64/5level-paging.rst for more 1494 information. 1495 1496 Say N if unsure. 1497 1498config X86_DIRECT_GBPAGES 1499 def_bool y 1500 depends on X86_64 1501 help 1502 Certain kernel features effectively disable kernel 1503 linear 1 GB mappings (even if the CPU otherwise 1504 supports them), so don't confuse the user by printing 1505 that we have them enabled. 1506 1507config X86_CPA_STATISTICS 1508 bool "Enable statistic for Change Page Attribute" 1509 depends on DEBUG_FS 1510 help 1511 Expose statistics about the Change Page Attribute mechanism, which 1512 helps to determine the effectiveness of preserving large and huge 1513 page mappings when mapping protections are changed. 1514 1515config AMD_MEM_ENCRYPT 1516 bool "AMD Secure Memory Encryption (SME) support" 1517 depends on X86_64 && CPU_SUP_AMD 1518 select DMA_COHERENT_POOL 1519 select DYNAMIC_PHYSICAL_MASK 1520 select ARCH_USE_MEMREMAP_PROT 1521 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1522 help 1523 Say yes to enable support for the encryption of system memory. 1524 This requires an AMD processor that supports Secure Memory 1525 Encryption (SME). 1526 1527config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1528 bool "Activate AMD Secure Memory Encryption (SME) by default" 1529 default y 1530 depends on AMD_MEM_ENCRYPT 1531 help 1532 Say yes to have system memory encrypted by default if running on 1533 an AMD processor that supports Secure Memory Encryption (SME). 1534 1535 If set to Y, then the encryption of system memory can be 1536 deactivated with the mem_encrypt=off command line option. 1537 1538 If set to N, then the encryption of system memory can be 1539 activated with the mem_encrypt=on command line option. 1540 1541# Common NUMA Features 1542config NUMA 1543 bool "NUMA Memory Allocation and Scheduler Support" 1544 depends on SMP 1545 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1546 default y if X86_BIGSMP 1547 help 1548 Enable NUMA (Non-Uniform Memory Access) support. 1549 1550 The kernel will try to allocate memory used by a CPU on the 1551 local memory controller of the CPU and add some more 1552 NUMA awareness to the kernel. 1553 1554 For 64-bit this is recommended if the system is Intel Core i7 1555 (or later), AMD Opteron, or EM64T NUMA. 1556 1557 For 32-bit this is only needed if you boot a 32-bit 1558 kernel on a 64-bit NUMA platform. 1559 1560 Otherwise, you should say N. 1561 1562config AMD_NUMA 1563 def_bool y 1564 prompt "Old style AMD Opteron NUMA detection" 1565 depends on X86_64 && NUMA && PCI 1566 help 1567 Enable AMD NUMA node topology detection. You should say Y here if 1568 you have a multi processor AMD system. This uses an old method to 1569 read the NUMA configuration directly from the builtin Northbridge 1570 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1571 which also takes priority if both are compiled in. 1572 1573config X86_64_ACPI_NUMA 1574 def_bool y 1575 prompt "ACPI NUMA detection" 1576 depends on X86_64 && NUMA && ACPI && PCI 1577 select ACPI_NUMA 1578 help 1579 Enable ACPI SRAT based node topology detection. 1580 1581config NUMA_EMU 1582 bool "NUMA emulation" 1583 depends on NUMA 1584 help 1585 Enable NUMA emulation. A flat machine will be split 1586 into virtual nodes when booted with "numa=fake=N", where N is the 1587 number of nodes. This is only useful for debugging. 1588 1589config NODES_SHIFT 1590 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1591 range 1 10 1592 default "10" if MAXSMP 1593 default "6" if X86_64 1594 default "3" 1595 depends on NEED_MULTIPLE_NODES 1596 help 1597 Specify the maximum number of NUMA Nodes available on the target 1598 system. Increases memory reserved to accommodate various tables. 1599 1600config ARCH_FLATMEM_ENABLE 1601 def_bool y 1602 depends on X86_32 && !NUMA 1603 1604config ARCH_SPARSEMEM_ENABLE 1605 def_bool y 1606 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1607 select SPARSEMEM_STATIC if X86_32 1608 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1609 1610config ARCH_SPARSEMEM_DEFAULT 1611 def_bool X86_64 || (NUMA && X86_32) 1612 1613config ARCH_SELECT_MEMORY_MODEL 1614 def_bool y 1615 depends on ARCH_SPARSEMEM_ENABLE 1616 1617config ARCH_MEMORY_PROBE 1618 bool "Enable sysfs memory/probe interface" 1619 depends on X86_64 && MEMORY_HOTPLUG 1620 help 1621 This option enables a sysfs memory/probe interface for testing. 1622 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1623 If you are unsure how to answer this question, answer N. 1624 1625config ARCH_PROC_KCORE_TEXT 1626 def_bool y 1627 depends on X86_64 && PROC_KCORE 1628 1629config ILLEGAL_POINTER_VALUE 1630 hex 1631 default 0 if X86_32 1632 default 0xdead000000000000 if X86_64 1633 1634config X86_PMEM_LEGACY_DEVICE 1635 bool 1636 1637config X86_PMEM_LEGACY 1638 tristate "Support non-standard NVDIMMs and ADR protected memory" 1639 depends on PHYS_ADDR_T_64BIT 1640 depends on BLK_DEV 1641 select X86_PMEM_LEGACY_DEVICE 1642 select NUMA_KEEP_MEMINFO if NUMA 1643 select LIBNVDIMM 1644 help 1645 Treat memory marked using the non-standard e820 type of 12 as used 1646 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1647 The kernel will offer these regions to the 'pmem' driver so 1648 they can be used for persistent storage. 1649 1650 Say Y if unsure. 1651 1652config HIGHPTE 1653 bool "Allocate 3rd-level pagetables from highmem" 1654 depends on HIGHMEM 1655 help 1656 The VM uses one page table entry for each page of physical memory. 1657 For systems with a lot of RAM, this can be wasteful of precious 1658 low memory. Setting this option will put user-space page table 1659 entries in high memory. 1660 1661config X86_CHECK_BIOS_CORRUPTION 1662 bool "Check for low memory corruption" 1663 help 1664 Periodically check for memory corruption in low memory, which 1665 is suspected to be caused by BIOS. Even when enabled in the 1666 configuration, it is disabled at runtime. Enable it by 1667 setting "memory_corruption_check=1" on the kernel command 1668 line. By default it scans the low 64k of memory every 60 1669 seconds; see the memory_corruption_check_size and 1670 memory_corruption_check_period parameters in 1671 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1672 1673 When enabled with the default parameters, this option has 1674 almost no overhead, as it reserves a relatively small amount 1675 of memory and scans it infrequently. It both detects corruption 1676 and prevents it from affecting the running system. 1677 1678 It is, however, intended as a diagnostic tool; if repeatable 1679 BIOS-originated corruption always affects the same memory, 1680 you can use memmap= to prevent the kernel from using that 1681 memory. 1682 1683config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1684 bool "Set the default setting of memory_corruption_check" 1685 depends on X86_CHECK_BIOS_CORRUPTION 1686 default y 1687 help 1688 Set whether the default state of memory_corruption_check is 1689 on or off. 1690 1691config X86_RESERVE_LOW 1692 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1693 default 64 1694 range 4 640 1695 help 1696 Specify the amount of low memory to reserve for the BIOS. 1697 1698 The first page contains BIOS data structures that the kernel 1699 must not use, so that page must always be reserved. 1700 1701 By default we reserve the first 64K of physical RAM, as a 1702 number of BIOSes are known to corrupt that memory range 1703 during events such as suspend/resume or monitor cable 1704 insertion, so it must not be used by the kernel. 1705 1706 You can set this to 4 if you are absolutely sure that you 1707 trust the BIOS to get all its memory reservations and usages 1708 right. If you know your BIOS have problems beyond the 1709 default 64K area, you can set this to 640 to avoid using the 1710 entire low memory range. 1711 1712 If you have doubts about the BIOS (e.g. suspend/resume does 1713 not work or there's kernel crashes after certain hardware 1714 hotplug events) then you might want to enable 1715 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1716 typical corruption patterns. 1717 1718 Leave this to the default value of 64 if you are unsure. 1719 1720config MATH_EMULATION 1721 bool 1722 depends on MODIFY_LDT_SYSCALL 1723 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1724 help 1725 Linux can emulate a math coprocessor (used for floating point 1726 operations) if you don't have one. 486DX and Pentium processors have 1727 a math coprocessor built in, 486SX and 386 do not, unless you added 1728 a 487DX or 387, respectively. (The messages during boot time can 1729 give you some hints here ["man dmesg"].) Everyone needs either a 1730 coprocessor or this emulation. 1731 1732 If you don't have a math coprocessor, you need to say Y here; if you 1733 say Y here even though you have a coprocessor, the coprocessor will 1734 be used nevertheless. (This behavior can be changed with the kernel 1735 command line option "no387", which comes handy if your coprocessor 1736 is broken. Try "man bootparam" or see the documentation of your boot 1737 loader (lilo or loadlin) about how to pass options to the kernel at 1738 boot time.) This means that it is a good idea to say Y here if you 1739 intend to use this kernel on different machines. 1740 1741 More information about the internals of the Linux math coprocessor 1742 emulation can be found in <file:arch/x86/math-emu/README>. 1743 1744 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1745 kernel, it won't hurt. 1746 1747config MTRR 1748 def_bool y 1749 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1750 help 1751 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1752 the Memory Type Range Registers (MTRRs) may be used to control 1753 processor access to memory ranges. This is most useful if you have 1754 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1755 allows bus write transfers to be combined into a larger transfer 1756 before bursting over the PCI/AGP bus. This can increase performance 1757 of image write operations 2.5 times or more. Saying Y here creates a 1758 /proc/mtrr file which may be used to manipulate your processor's 1759 MTRRs. Typically the X server should use this. 1760 1761 This code has a reasonably generic interface so that similar 1762 control registers on other processors can be easily supported 1763 as well: 1764 1765 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1766 Registers (ARRs) which provide a similar functionality to MTRRs. For 1767 these, the ARRs are used to emulate the MTRRs. 1768 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1769 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1770 write-combining. All of these processors are supported by this code 1771 and it makes sense to say Y here if you have one of them. 1772 1773 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1774 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1775 can lead to all sorts of problems, so it's good to say Y here. 1776 1777 You can safely say Y even if your machine doesn't have MTRRs, you'll 1778 just add about 9 KB to your kernel. 1779 1780 See <file:Documentation/x86/mtrr.rst> for more information. 1781 1782config MTRR_SANITIZER 1783 def_bool y 1784 prompt "MTRR cleanup support" 1785 depends on MTRR 1786 help 1787 Convert MTRR layout from continuous to discrete, so X drivers can 1788 add writeback entries. 1789 1790 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1791 The largest mtrr entry size for a continuous block can be set with 1792 mtrr_chunk_size. 1793 1794 If unsure, say Y. 1795 1796config MTRR_SANITIZER_ENABLE_DEFAULT 1797 int "MTRR cleanup enable value (0-1)" 1798 range 0 1 1799 default "0" 1800 depends on MTRR_SANITIZER 1801 help 1802 Enable mtrr cleanup default value 1803 1804config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1805 int "MTRR cleanup spare reg num (0-7)" 1806 range 0 7 1807 default "1" 1808 depends on MTRR_SANITIZER 1809 help 1810 mtrr cleanup spare entries default, it can be changed via 1811 mtrr_spare_reg_nr=N on the kernel command line. 1812 1813config X86_PAT 1814 def_bool y 1815 prompt "x86 PAT support" if EXPERT 1816 depends on MTRR 1817 help 1818 Use PAT attributes to setup page level cache control. 1819 1820 PATs are the modern equivalents of MTRRs and are much more 1821 flexible than MTRRs. 1822 1823 Say N here if you see bootup problems (boot crash, boot hang, 1824 spontaneous reboots) or a non-working video driver. 1825 1826 If unsure, say Y. 1827 1828config ARCH_USES_PG_UNCACHED 1829 def_bool y 1830 depends on X86_PAT 1831 1832config ARCH_RANDOM 1833 def_bool y 1834 prompt "x86 architectural random number generator" if EXPERT 1835 help 1836 Enable the x86 architectural RDRAND instruction 1837 (Intel Bull Mountain technology) to generate random numbers. 1838 If supported, this is a high bandwidth, cryptographically 1839 secure hardware random number generator. 1840 1841config X86_SMAP 1842 def_bool y 1843 prompt "Supervisor Mode Access Prevention" if EXPERT 1844 help 1845 Supervisor Mode Access Prevention (SMAP) is a security 1846 feature in newer Intel processors. There is a small 1847 performance cost if this enabled and turned on; there is 1848 also a small increase in the kernel size if this is enabled. 1849 1850 If unsure, say Y. 1851 1852config X86_UMIP 1853 def_bool y 1854 prompt "User Mode Instruction Prevention" if EXPERT 1855 help 1856 User Mode Instruction Prevention (UMIP) is a security feature in 1857 some x86 processors. If enabled, a general protection fault is 1858 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1859 executed in user mode. These instructions unnecessarily expose 1860 information about the hardware state. 1861 1862 The vast majority of applications do not use these instructions. 1863 For the very few that do, software emulation is provided in 1864 specific cases in protected and virtual-8086 modes. Emulated 1865 results are dummy. 1866 1867config X86_INTEL_MEMORY_PROTECTION_KEYS 1868 prompt "Memory Protection Keys" 1869 def_bool y 1870 # Note: only available in 64-bit mode 1871 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1872 select ARCH_USES_HIGH_VMA_FLAGS 1873 select ARCH_HAS_PKEYS 1874 help 1875 Memory Protection Keys provides a mechanism for enforcing 1876 page-based protections, but without requiring modification of the 1877 page tables when an application changes protection domains. 1878 1879 For details, see Documentation/core-api/protection-keys.rst 1880 1881 If unsure, say y. 1882 1883choice 1884 prompt "TSX enable mode" 1885 depends on CPU_SUP_INTEL 1886 default X86_INTEL_TSX_MODE_OFF 1887 help 1888 Intel's TSX (Transactional Synchronization Extensions) feature 1889 allows to optimize locking protocols through lock elision which 1890 can lead to a noticeable performance boost. 1891 1892 On the other hand it has been shown that TSX can be exploited 1893 to form side channel attacks (e.g. TAA) and chances are there 1894 will be more of those attacks discovered in the future. 1895 1896 Therefore TSX is not enabled by default (aka tsx=off). An admin 1897 might override this decision by tsx=on the command line parameter. 1898 Even with TSX enabled, the kernel will attempt to enable the best 1899 possible TAA mitigation setting depending on the microcode available 1900 for the particular machine. 1901 1902 This option allows to set the default tsx mode between tsx=on, =off 1903 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1904 details. 1905 1906 Say off if not sure, auto if TSX is in use but it should be used on safe 1907 platforms or on if TSX is in use and the security aspect of tsx is not 1908 relevant. 1909 1910config X86_INTEL_TSX_MODE_OFF 1911 bool "off" 1912 help 1913 TSX is disabled if possible - equals to tsx=off command line parameter. 1914 1915config X86_INTEL_TSX_MODE_ON 1916 bool "on" 1917 help 1918 TSX is always enabled on TSX capable HW - equals the tsx=on command 1919 line parameter. 1920 1921config X86_INTEL_TSX_MODE_AUTO 1922 bool "auto" 1923 help 1924 TSX is enabled on TSX capable HW that is believed to be safe against 1925 side channel attacks- equals the tsx=auto command line parameter. 1926endchoice 1927 1928config EFI 1929 bool "EFI runtime service support" 1930 depends on ACPI 1931 select UCS2_STRING 1932 select EFI_RUNTIME_WRAPPERS 1933 help 1934 This enables the kernel to use EFI runtime services that are 1935 available (such as the EFI variable services). 1936 1937 This option is only useful on systems that have EFI firmware. 1938 In addition, you should use the latest ELILO loader available 1939 at <http://elilo.sourceforge.net> in order to take advantage 1940 of EFI runtime services. However, even with this option, the 1941 resultant kernel should continue to boot on existing non-EFI 1942 platforms. 1943 1944config EFI_STUB 1945 bool "EFI stub support" 1946 depends on EFI && !X86_USE_3DNOW 1947 depends on $(cc-option,-mabi=ms) || X86_32 1948 select RELOCATABLE 1949 help 1950 This kernel feature allows a bzImage to be loaded directly 1951 by EFI firmware without the use of a bootloader. 1952 1953 See Documentation/admin-guide/efi-stub.rst for more information. 1954 1955config EFI_MIXED 1956 bool "EFI mixed-mode support" 1957 depends on EFI_STUB && X86_64 1958 help 1959 Enabling this feature allows a 64-bit kernel to be booted 1960 on a 32-bit firmware, provided that your CPU supports 64-bit 1961 mode. 1962 1963 Note that it is not possible to boot a mixed-mode enabled 1964 kernel via the EFI boot stub - a bootloader that supports 1965 the EFI handover protocol must be used. 1966 1967 If unsure, say N. 1968 1969config SECCOMP 1970 def_bool y 1971 prompt "Enable seccomp to safely compute untrusted bytecode" 1972 help 1973 This kernel feature is useful for number crunching applications 1974 that may need to compute untrusted bytecode during their 1975 execution. By using pipes or other transports made available to 1976 the process as file descriptors supporting the read/write 1977 syscalls, it's possible to isolate those applications in 1978 their own address space using seccomp. Once seccomp is 1979 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 1980 and the task is only allowed to execute a few safe syscalls 1981 defined by each seccomp mode. 1982 1983 If unsure, say Y. Only embedded should say N here. 1984 1985source "kernel/Kconfig.hz" 1986 1987config KEXEC 1988 bool "kexec system call" 1989 select KEXEC_CORE 1990 help 1991 kexec is a system call that implements the ability to shutdown your 1992 current kernel, and to start another kernel. It is like a reboot 1993 but it is independent of the system firmware. And like a reboot 1994 you can start any kernel with it, not just Linux. 1995 1996 The name comes from the similarity to the exec system call. 1997 1998 It is an ongoing process to be certain the hardware in a machine 1999 is properly shutdown, so do not be surprised if this code does not 2000 initially work for you. As of this writing the exact hardware 2001 interface is strongly in flux, so no good recommendation can be 2002 made. 2003 2004config KEXEC_FILE 2005 bool "kexec file based system call" 2006 select KEXEC_CORE 2007 select BUILD_BIN2C 2008 depends on X86_64 2009 depends on CRYPTO=y 2010 depends on CRYPTO_SHA256=y 2011 help 2012 This is new version of kexec system call. This system call is 2013 file based and takes file descriptors as system call argument 2014 for kernel and initramfs as opposed to list of segments as 2015 accepted by previous system call. 2016 2017config ARCH_HAS_KEXEC_PURGATORY 2018 def_bool KEXEC_FILE 2019 2020config KEXEC_SIG 2021 bool "Verify kernel signature during kexec_file_load() syscall" 2022 depends on KEXEC_FILE 2023 help 2024 2025 This option makes the kexec_file_load() syscall check for a valid 2026 signature of the kernel image. The image can still be loaded without 2027 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2028 there's a signature that we can check, then it must be valid. 2029 2030 In addition to this option, you need to enable signature 2031 verification for the corresponding kernel image type being 2032 loaded in order for this to work. 2033 2034config KEXEC_SIG_FORCE 2035 bool "Require a valid signature in kexec_file_load() syscall" 2036 depends on KEXEC_SIG 2037 help 2038 This option makes kernel signature verification mandatory for 2039 the kexec_file_load() syscall. 2040 2041config KEXEC_BZIMAGE_VERIFY_SIG 2042 bool "Enable bzImage signature verification support" 2043 depends on KEXEC_SIG 2044 depends on SIGNED_PE_FILE_VERIFICATION 2045 select SYSTEM_TRUSTED_KEYRING 2046 help 2047 Enable bzImage signature verification support. 2048 2049config CRASH_DUMP 2050 bool "kernel crash dumps" 2051 depends on X86_64 || (X86_32 && HIGHMEM) 2052 help 2053 Generate crash dump after being started by kexec. 2054 This should be normally only set in special crash dump kernels 2055 which are loaded in the main kernel with kexec-tools into 2056 a specially reserved region and then later executed after 2057 a crash by kdump/kexec. The crash dump kernel must be compiled 2058 to a memory address not used by the main kernel or BIOS using 2059 PHYSICAL_START, or it must be built as a relocatable image 2060 (CONFIG_RELOCATABLE=y). 2061 For more details see Documentation/admin-guide/kdump/kdump.rst 2062 2063config KEXEC_JUMP 2064 bool "kexec jump" 2065 depends on KEXEC && HIBERNATION 2066 help 2067 Jump between original kernel and kexeced kernel and invoke 2068 code in physical address mode via KEXEC 2069 2070config PHYSICAL_START 2071 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2072 default "0x1000000" 2073 help 2074 This gives the physical address where the kernel is loaded. 2075 2076 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2077 bzImage will decompress itself to above physical address and 2078 run from there. Otherwise, bzImage will run from the address where 2079 it has been loaded by the boot loader and will ignore above physical 2080 address. 2081 2082 In normal kdump cases one does not have to set/change this option 2083 as now bzImage can be compiled as a completely relocatable image 2084 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2085 address. This option is mainly useful for the folks who don't want 2086 to use a bzImage for capturing the crash dump and want to use a 2087 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2088 to be specifically compiled to run from a specific memory area 2089 (normally a reserved region) and this option comes handy. 2090 2091 So if you are using bzImage for capturing the crash dump, 2092 leave the value here unchanged to 0x1000000 and set 2093 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2094 for capturing the crash dump change this value to start of 2095 the reserved region. In other words, it can be set based on 2096 the "X" value as specified in the "crashkernel=YM@XM" 2097 command line boot parameter passed to the panic-ed 2098 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2099 for more details about crash dumps. 2100 2101 Usage of bzImage for capturing the crash dump is recommended as 2102 one does not have to build two kernels. Same kernel can be used 2103 as production kernel and capture kernel. Above option should have 2104 gone away after relocatable bzImage support is introduced. But it 2105 is present because there are users out there who continue to use 2106 vmlinux for dump capture. This option should go away down the 2107 line. 2108 2109 Don't change this unless you know what you are doing. 2110 2111config RELOCATABLE 2112 bool "Build a relocatable kernel" 2113 default y 2114 help 2115 This builds a kernel image that retains relocation information 2116 so it can be loaded someplace besides the default 1MB. 2117 The relocations tend to make the kernel binary about 10% larger, 2118 but are discarded at runtime. 2119 2120 One use is for the kexec on panic case where the recovery kernel 2121 must live at a different physical address than the primary 2122 kernel. 2123 2124 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2125 it has been loaded at and the compile time physical address 2126 (CONFIG_PHYSICAL_START) is used as the minimum location. 2127 2128config RANDOMIZE_BASE 2129 bool "Randomize the address of the kernel image (KASLR)" 2130 depends on RELOCATABLE 2131 default y 2132 help 2133 In support of Kernel Address Space Layout Randomization (KASLR), 2134 this randomizes the physical address at which the kernel image 2135 is decompressed and the virtual address where the kernel 2136 image is mapped, as a security feature that deters exploit 2137 attempts relying on knowledge of the location of kernel 2138 code internals. 2139 2140 On 64-bit, the kernel physical and virtual addresses are 2141 randomized separately. The physical address will be anywhere 2142 between 16MB and the top of physical memory (up to 64TB). The 2143 virtual address will be randomized from 16MB up to 1GB (9 bits 2144 of entropy). Note that this also reduces the memory space 2145 available to kernel modules from 1.5GB to 1GB. 2146 2147 On 32-bit, the kernel physical and virtual addresses are 2148 randomized together. They will be randomized from 16MB up to 2149 512MB (8 bits of entropy). 2150 2151 Entropy is generated using the RDRAND instruction if it is 2152 supported. If RDTSC is supported, its value is mixed into 2153 the entropy pool as well. If neither RDRAND nor RDTSC are 2154 supported, then entropy is read from the i8254 timer. The 2155 usable entropy is limited by the kernel being built using 2156 2GB addressing, and that PHYSICAL_ALIGN must be at a 2157 minimum of 2MB. As a result, only 10 bits of entropy are 2158 theoretically possible, but the implementations are further 2159 limited due to memory layouts. 2160 2161 If unsure, say Y. 2162 2163# Relocation on x86 needs some additional build support 2164config X86_NEED_RELOCS 2165 def_bool y 2166 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2167 2168config PHYSICAL_ALIGN 2169 hex "Alignment value to which kernel should be aligned" 2170 default "0x200000" 2171 range 0x2000 0x1000000 if X86_32 2172 range 0x200000 0x1000000 if X86_64 2173 help 2174 This value puts the alignment restrictions on physical address 2175 where kernel is loaded and run from. Kernel is compiled for an 2176 address which meets above alignment restriction. 2177 2178 If bootloader loads the kernel at a non-aligned address and 2179 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2180 address aligned to above value and run from there. 2181 2182 If bootloader loads the kernel at a non-aligned address and 2183 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2184 load address and decompress itself to the address it has been 2185 compiled for and run from there. The address for which kernel is 2186 compiled already meets above alignment restrictions. Hence the 2187 end result is that kernel runs from a physical address meeting 2188 above alignment restrictions. 2189 2190 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2191 this value must be a multiple of 0x200000. 2192 2193 Don't change this unless you know what you are doing. 2194 2195config DYNAMIC_MEMORY_LAYOUT 2196 bool 2197 help 2198 This option makes base addresses of vmalloc and vmemmap as well as 2199 __PAGE_OFFSET movable during boot. 2200 2201config RANDOMIZE_MEMORY 2202 bool "Randomize the kernel memory sections" 2203 depends on X86_64 2204 depends on RANDOMIZE_BASE 2205 select DYNAMIC_MEMORY_LAYOUT 2206 default RANDOMIZE_BASE 2207 help 2208 Randomizes the base virtual address of kernel memory sections 2209 (physical memory mapping, vmalloc & vmemmap). This security feature 2210 makes exploits relying on predictable memory locations less reliable. 2211 2212 The order of allocations remains unchanged. Entropy is generated in 2213 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2214 configuration have in average 30,000 different possible virtual 2215 addresses for each memory section. 2216 2217 If unsure, say Y. 2218 2219config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2220 hex "Physical memory mapping padding" if EXPERT 2221 depends on RANDOMIZE_MEMORY 2222 default "0xa" if MEMORY_HOTPLUG 2223 default "0x0" 2224 range 0x1 0x40 if MEMORY_HOTPLUG 2225 range 0x0 0x40 2226 help 2227 Define the padding in terabytes added to the existing physical 2228 memory size during kernel memory randomization. It is useful 2229 for memory hotplug support but reduces the entropy available for 2230 address randomization. 2231 2232 If unsure, leave at the default value. 2233 2234config HOTPLUG_CPU 2235 def_bool y 2236 depends on SMP 2237 2238config BOOTPARAM_HOTPLUG_CPU0 2239 bool "Set default setting of cpu0_hotpluggable" 2240 depends on HOTPLUG_CPU 2241 help 2242 Set whether default state of cpu0_hotpluggable is on or off. 2243 2244 Say Y here to enable CPU0 hotplug by default. If this switch 2245 is turned on, there is no need to give cpu0_hotplug kernel 2246 parameter and the CPU0 hotplug feature is enabled by default. 2247 2248 Please note: there are two known CPU0 dependencies if you want 2249 to enable the CPU0 hotplug feature either by this switch or by 2250 cpu0_hotplug kernel parameter. 2251 2252 First, resume from hibernate or suspend always starts from CPU0. 2253 So hibernate and suspend are prevented if CPU0 is offline. 2254 2255 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2256 offline if any interrupt can not migrate out of CPU0. There may 2257 be other CPU0 dependencies. 2258 2259 Please make sure the dependencies are under your control before 2260 you enable this feature. 2261 2262 Say N if you don't want to enable CPU0 hotplug feature by default. 2263 You still can enable the CPU0 hotplug feature at boot by kernel 2264 parameter cpu0_hotplug. 2265 2266config DEBUG_HOTPLUG_CPU0 2267 def_bool n 2268 prompt "Debug CPU0 hotplug" 2269 depends on HOTPLUG_CPU 2270 help 2271 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2272 soon as possible and boots up userspace with CPU0 offlined. User 2273 can online CPU0 back after boot time. 2274 2275 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2276 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2277 compilation or giving cpu0_hotplug kernel parameter at boot. 2278 2279 If unsure, say N. 2280 2281config COMPAT_VDSO 2282 def_bool n 2283 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2284 depends on COMPAT_32 2285 help 2286 Certain buggy versions of glibc will crash if they are 2287 presented with a 32-bit vDSO that is not mapped at the address 2288 indicated in its segment table. 2289 2290 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2291 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2292 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2293 the only released version with the bug, but OpenSUSE 9 2294 contains a buggy "glibc 2.3.2". 2295 2296 The symptom of the bug is that everything crashes on startup, saying: 2297 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2298 2299 Saying Y here changes the default value of the vdso32 boot 2300 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2301 This works around the glibc bug but hurts performance. 2302 2303 If unsure, say N: if you are compiling your own kernel, you 2304 are unlikely to be using a buggy version of glibc. 2305 2306choice 2307 prompt "vsyscall table for legacy applications" 2308 depends on X86_64 2309 default LEGACY_VSYSCALL_XONLY 2310 help 2311 Legacy user code that does not know how to find the vDSO expects 2312 to be able to issue three syscalls by calling fixed addresses in 2313 kernel space. Since this location is not randomized with ASLR, 2314 it can be used to assist security vulnerability exploitation. 2315 2316 This setting can be changed at boot time via the kernel command 2317 line parameter vsyscall=[emulate|xonly|none]. 2318 2319 On a system with recent enough glibc (2.14 or newer) and no 2320 static binaries, you can say None without a performance penalty 2321 to improve security. 2322 2323 If unsure, select "Emulate execution only". 2324 2325 config LEGACY_VSYSCALL_EMULATE 2326 bool "Full emulation" 2327 help 2328 The kernel traps and emulates calls into the fixed vsyscall 2329 address mapping. This makes the mapping non-executable, but 2330 it still contains readable known contents, which could be 2331 used in certain rare security vulnerability exploits. This 2332 configuration is recommended when using legacy userspace 2333 that still uses vsyscalls along with legacy binary 2334 instrumentation tools that require code to be readable. 2335 2336 An example of this type of legacy userspace is running 2337 Pin on an old binary that still uses vsyscalls. 2338 2339 config LEGACY_VSYSCALL_XONLY 2340 bool "Emulate execution only" 2341 help 2342 The kernel traps and emulates calls into the fixed vsyscall 2343 address mapping and does not allow reads. This 2344 configuration is recommended when userspace might use the 2345 legacy vsyscall area but support for legacy binary 2346 instrumentation of legacy code is not needed. It mitigates 2347 certain uses of the vsyscall area as an ASLR-bypassing 2348 buffer. 2349 2350 config LEGACY_VSYSCALL_NONE 2351 bool "None" 2352 help 2353 There will be no vsyscall mapping at all. This will 2354 eliminate any risk of ASLR bypass due to the vsyscall 2355 fixed address mapping. Attempts to use the vsyscalls 2356 will be reported to dmesg, so that either old or 2357 malicious userspace programs can be identified. 2358 2359endchoice 2360 2361config CMDLINE_BOOL 2362 bool "Built-in kernel command line" 2363 help 2364 Allow for specifying boot arguments to the kernel at 2365 build time. On some systems (e.g. embedded ones), it is 2366 necessary or convenient to provide some or all of the 2367 kernel boot arguments with the kernel itself (that is, 2368 to not rely on the boot loader to provide them.) 2369 2370 To compile command line arguments into the kernel, 2371 set this option to 'Y', then fill in the 2372 boot arguments in CONFIG_CMDLINE. 2373 2374 Systems with fully functional boot loaders (i.e. non-embedded) 2375 should leave this option set to 'N'. 2376 2377config CMDLINE 2378 string "Built-in kernel command string" 2379 depends on CMDLINE_BOOL 2380 default "" 2381 help 2382 Enter arguments here that should be compiled into the kernel 2383 image and used at boot time. If the boot loader provides a 2384 command line at boot time, it is appended to this string to 2385 form the full kernel command line, when the system boots. 2386 2387 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2388 change this behavior. 2389 2390 In most cases, the command line (whether built-in or provided 2391 by the boot loader) should specify the device for the root 2392 file system. 2393 2394config CMDLINE_OVERRIDE 2395 bool "Built-in command line overrides boot loader arguments" 2396 depends on CMDLINE_BOOL && CMDLINE != "" 2397 help 2398 Set this option to 'Y' to have the kernel ignore the boot loader 2399 command line, and use ONLY the built-in command line. 2400 2401 This is used to work around broken boot loaders. This should 2402 be set to 'N' under normal conditions. 2403 2404config MODIFY_LDT_SYSCALL 2405 bool "Enable the LDT (local descriptor table)" if EXPERT 2406 default y 2407 help 2408 Linux can allow user programs to install a per-process x86 2409 Local Descriptor Table (LDT) using the modify_ldt(2) system 2410 call. This is required to run 16-bit or segmented code such as 2411 DOSEMU or some Wine programs. It is also used by some very old 2412 threading libraries. 2413 2414 Enabling this feature adds a small amount of overhead to 2415 context switches and increases the low-level kernel attack 2416 surface. Disabling it removes the modify_ldt(2) system call. 2417 2418 Saying 'N' here may make sense for embedded or server kernels. 2419 2420source "kernel/livepatch/Kconfig" 2421 2422endmenu 2423 2424config ARCH_HAS_ADD_PAGES 2425 def_bool y 2426 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2427 2428config ARCH_ENABLE_MEMORY_HOTPLUG 2429 def_bool y 2430 depends on X86_64 || (X86_32 && HIGHMEM) 2431 2432config ARCH_ENABLE_MEMORY_HOTREMOVE 2433 def_bool y 2434 depends on MEMORY_HOTPLUG 2435 2436config USE_PERCPU_NUMA_NODE_ID 2437 def_bool y 2438 depends on NUMA 2439 2440config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2441 def_bool y 2442 depends on X86_64 || X86_PAE 2443 2444config ARCH_ENABLE_HUGEPAGE_MIGRATION 2445 def_bool y 2446 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2447 2448config ARCH_ENABLE_THP_MIGRATION 2449 def_bool y 2450 depends on X86_64 && TRANSPARENT_HUGEPAGE 2451 2452menu "Power management and ACPI options" 2453 2454config ARCH_HIBERNATION_HEADER 2455 def_bool y 2456 depends on HIBERNATION 2457 2458source "kernel/power/Kconfig" 2459 2460source "drivers/acpi/Kconfig" 2461 2462source "drivers/sfi/Kconfig" 2463 2464config X86_APM_BOOT 2465 def_bool y 2466 depends on APM 2467 2468menuconfig APM 2469 tristate "APM (Advanced Power Management) BIOS support" 2470 depends on X86_32 && PM_SLEEP 2471 help 2472 APM is a BIOS specification for saving power using several different 2473 techniques. This is mostly useful for battery powered laptops with 2474 APM compliant BIOSes. If you say Y here, the system time will be 2475 reset after a RESUME operation, the /proc/apm device will provide 2476 battery status information, and user-space programs will receive 2477 notification of APM "events" (e.g. battery status change). 2478 2479 If you select "Y" here, you can disable actual use of the APM 2480 BIOS by passing the "apm=off" option to the kernel at boot time. 2481 2482 Note that the APM support is almost completely disabled for 2483 machines with more than one CPU. 2484 2485 In order to use APM, you will need supporting software. For location 2486 and more information, read <file:Documentation/power/apm-acpi.rst> 2487 and the Battery Powered Linux mini-HOWTO, available from 2488 <http://www.tldp.org/docs.html#howto>. 2489 2490 This driver does not spin down disk drives (see the hdparm(8) 2491 manpage ("man 8 hdparm") for that), and it doesn't turn off 2492 VESA-compliant "green" monitors. 2493 2494 This driver does not support the TI 4000M TravelMate and the ACER 2495 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2496 desktop machines also don't have compliant BIOSes, and this driver 2497 may cause those machines to panic during the boot phase. 2498 2499 Generally, if you don't have a battery in your machine, there isn't 2500 much point in using this driver and you should say N. If you get 2501 random kernel OOPSes or reboots that don't seem to be related to 2502 anything, try disabling/enabling this option (or disabling/enabling 2503 APM in your BIOS). 2504 2505 Some other things you should try when experiencing seemingly random, 2506 "weird" problems: 2507 2508 1) make sure that you have enough swap space and that it is 2509 enabled. 2510 2) pass the "no-hlt" option to the kernel 2511 3) switch on floating point emulation in the kernel and pass 2512 the "no387" option to the kernel 2513 4) pass the "floppy=nodma" option to the kernel 2514 5) pass the "mem=4M" option to the kernel (thereby disabling 2515 all but the first 4 MB of RAM) 2516 6) make sure that the CPU is not over clocked. 2517 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2518 8) disable the cache from your BIOS settings 2519 9) install a fan for the video card or exchange video RAM 2520 10) install a better fan for the CPU 2521 11) exchange RAM chips 2522 12) exchange the motherboard. 2523 2524 To compile this driver as a module, choose M here: the 2525 module will be called apm. 2526 2527if APM 2528 2529config APM_IGNORE_USER_SUSPEND 2530 bool "Ignore USER SUSPEND" 2531 help 2532 This option will ignore USER SUSPEND requests. On machines with a 2533 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2534 series notebooks, it is necessary to say Y because of a BIOS bug. 2535 2536config APM_DO_ENABLE 2537 bool "Enable PM at boot time" 2538 help 2539 Enable APM features at boot time. From page 36 of the APM BIOS 2540 specification: "When disabled, the APM BIOS does not automatically 2541 power manage devices, enter the Standby State, enter the Suspend 2542 State, or take power saving steps in response to CPU Idle calls." 2543 This driver will make CPU Idle calls when Linux is idle (unless this 2544 feature is turned off -- see "Do CPU IDLE calls", below). This 2545 should always save battery power, but more complicated APM features 2546 will be dependent on your BIOS implementation. You may need to turn 2547 this option off if your computer hangs at boot time when using APM 2548 support, or if it beeps continuously instead of suspending. Turn 2549 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2550 T400CDT. This is off by default since most machines do fine without 2551 this feature. 2552 2553config APM_CPU_IDLE 2554 depends on CPU_IDLE 2555 bool "Make CPU Idle calls when idle" 2556 help 2557 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2558 On some machines, this can activate improved power savings, such as 2559 a slowed CPU clock rate, when the machine is idle. These idle calls 2560 are made after the idle loop has run for some length of time (e.g., 2561 333 mS). On some machines, this will cause a hang at boot time or 2562 whenever the CPU becomes idle. (On machines with more than one CPU, 2563 this option does nothing.) 2564 2565config APM_DISPLAY_BLANK 2566 bool "Enable console blanking using APM" 2567 help 2568 Enable console blanking using the APM. Some laptops can use this to 2569 turn off the LCD backlight when the screen blanker of the Linux 2570 virtual console blanks the screen. Note that this is only used by 2571 the virtual console screen blanker, and won't turn off the backlight 2572 when using the X Window system. This also doesn't have anything to 2573 do with your VESA-compliant power-saving monitor. Further, this 2574 option doesn't work for all laptops -- it might not turn off your 2575 backlight at all, or it might print a lot of errors to the console, 2576 especially if you are using gpm. 2577 2578config APM_ALLOW_INTS 2579 bool "Allow interrupts during APM BIOS calls" 2580 help 2581 Normally we disable external interrupts while we are making calls to 2582 the APM BIOS as a measure to lessen the effects of a badly behaving 2583 BIOS implementation. The BIOS should reenable interrupts if it 2584 needs to. Unfortunately, some BIOSes do not -- especially those in 2585 many of the newer IBM Thinkpads. If you experience hangs when you 2586 suspend, try setting this to Y. Otherwise, say N. 2587 2588endif # APM 2589 2590source "drivers/cpufreq/Kconfig" 2591 2592source "drivers/cpuidle/Kconfig" 2593 2594source "drivers/idle/Kconfig" 2595 2596endmenu 2597 2598 2599menu "Bus options (PCI etc.)" 2600 2601choice 2602 prompt "PCI access mode" 2603 depends on X86_32 && PCI 2604 default PCI_GOANY 2605 help 2606 On PCI systems, the BIOS can be used to detect the PCI devices and 2607 determine their configuration. However, some old PCI motherboards 2608 have BIOS bugs and may crash if this is done. Also, some embedded 2609 PCI-based systems don't have any BIOS at all. Linux can also try to 2610 detect the PCI hardware directly without using the BIOS. 2611 2612 With this option, you can specify how Linux should detect the 2613 PCI devices. If you choose "BIOS", the BIOS will be used, 2614 if you choose "Direct", the BIOS won't be used, and if you 2615 choose "MMConfig", then PCI Express MMCONFIG will be used. 2616 If you choose "Any", the kernel will try MMCONFIG, then the 2617 direct access method and falls back to the BIOS if that doesn't 2618 work. If unsure, go with the default, which is "Any". 2619 2620config PCI_GOBIOS 2621 bool "BIOS" 2622 2623config PCI_GOMMCONFIG 2624 bool "MMConfig" 2625 2626config PCI_GODIRECT 2627 bool "Direct" 2628 2629config PCI_GOOLPC 2630 bool "OLPC XO-1" 2631 depends on OLPC 2632 2633config PCI_GOANY 2634 bool "Any" 2635 2636endchoice 2637 2638config PCI_BIOS 2639 def_bool y 2640 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2641 2642# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2643config PCI_DIRECT 2644 def_bool y 2645 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2646 2647config PCI_MMCONFIG 2648 bool "Support mmconfig PCI config space access" if X86_64 2649 default y 2650 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2651 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2652 2653config PCI_OLPC 2654 def_bool y 2655 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2656 2657config PCI_XEN 2658 def_bool y 2659 depends on PCI && XEN 2660 select SWIOTLB_XEN 2661 2662config MMCONF_FAM10H 2663 def_bool y 2664 depends on X86_64 && PCI_MMCONFIG && ACPI 2665 2666config PCI_CNB20LE_QUIRK 2667 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2668 depends on PCI 2669 help 2670 Read the PCI windows out of the CNB20LE host bridge. This allows 2671 PCI hotplug to work on systems with the CNB20LE chipset which do 2672 not have ACPI. 2673 2674 There's no public spec for this chipset, and this functionality 2675 is known to be incomplete. 2676 2677 You should say N unless you know you need this. 2678 2679config ISA_BUS 2680 bool "ISA bus support on modern systems" if EXPERT 2681 help 2682 Expose ISA bus device drivers and options available for selection and 2683 configuration. Enable this option if your target machine has an ISA 2684 bus. ISA is an older system, displaced by PCI and newer bus 2685 architectures -- if your target machine is modern, it probably does 2686 not have an ISA bus. 2687 2688 If unsure, say N. 2689 2690# x86_64 have no ISA slots, but can have ISA-style DMA. 2691config ISA_DMA_API 2692 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2693 default y 2694 help 2695 Enables ISA-style DMA support for devices requiring such controllers. 2696 If unsure, say Y. 2697 2698if X86_32 2699 2700config ISA 2701 bool "ISA support" 2702 help 2703 Find out whether you have ISA slots on your motherboard. ISA is the 2704 name of a bus system, i.e. the way the CPU talks to the other stuff 2705 inside your box. Other bus systems are PCI, EISA, MicroChannel 2706 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2707 newer boards don't support it. If you have ISA, say Y, otherwise N. 2708 2709config SCx200 2710 tristate "NatSemi SCx200 support" 2711 help 2712 This provides basic support for National Semiconductor's 2713 (now AMD's) Geode processors. The driver probes for the 2714 PCI-IDs of several on-chip devices, so its a good dependency 2715 for other scx200_* drivers. 2716 2717 If compiled as a module, the driver is named scx200. 2718 2719config SCx200HR_TIMER 2720 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2721 depends on SCx200 2722 default y 2723 help 2724 This driver provides a clocksource built upon the on-chip 2725 27MHz high-resolution timer. Its also a workaround for 2726 NSC Geode SC-1100's buggy TSC, which loses time when the 2727 processor goes idle (as is done by the scheduler). The 2728 other workaround is idle=poll boot option. 2729 2730config OLPC 2731 bool "One Laptop Per Child support" 2732 depends on !X86_PAE 2733 select GPIOLIB 2734 select OF 2735 select OF_PROMTREE 2736 select IRQ_DOMAIN 2737 select OLPC_EC 2738 help 2739 Add support for detecting the unique features of the OLPC 2740 XO hardware. 2741 2742config OLPC_XO1_PM 2743 bool "OLPC XO-1 Power Management" 2744 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2745 help 2746 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2747 2748config OLPC_XO1_RTC 2749 bool "OLPC XO-1 Real Time Clock" 2750 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2751 help 2752 Add support for the XO-1 real time clock, which can be used as a 2753 programmable wakeup source. 2754 2755config OLPC_XO1_SCI 2756 bool "OLPC XO-1 SCI extras" 2757 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2758 depends on INPUT=y 2759 select POWER_SUPPLY 2760 help 2761 Add support for SCI-based features of the OLPC XO-1 laptop: 2762 - EC-driven system wakeups 2763 - Power button 2764 - Ebook switch 2765 - Lid switch 2766 - AC adapter status updates 2767 - Battery status updates 2768 2769config OLPC_XO15_SCI 2770 bool "OLPC XO-1.5 SCI extras" 2771 depends on OLPC && ACPI 2772 select POWER_SUPPLY 2773 help 2774 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2775 - EC-driven system wakeups 2776 - AC adapter status updates 2777 - Battery status updates 2778 2779config ALIX 2780 bool "PCEngines ALIX System Support (LED setup)" 2781 select GPIOLIB 2782 help 2783 This option enables system support for the PCEngines ALIX. 2784 At present this just sets up LEDs for GPIO control on 2785 ALIX2/3/6 boards. However, other system specific setup should 2786 get added here. 2787 2788 Note: You must still enable the drivers for GPIO and LED support 2789 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2790 2791 Note: You have to set alix.force=1 for boards with Award BIOS. 2792 2793config NET5501 2794 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2795 select GPIOLIB 2796 help 2797 This option enables system support for the Soekris Engineering net5501. 2798 2799config GEOS 2800 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2801 select GPIOLIB 2802 depends on DMI 2803 help 2804 This option enables system support for the Traverse Technologies GEOS. 2805 2806config TS5500 2807 bool "Technologic Systems TS-5500 platform support" 2808 depends on MELAN 2809 select CHECK_SIGNATURE 2810 select NEW_LEDS 2811 select LEDS_CLASS 2812 help 2813 This option enables system support for the Technologic Systems TS-5500. 2814 2815endif # X86_32 2816 2817config AMD_NB 2818 def_bool y 2819 depends on CPU_SUP_AMD && PCI 2820 2821config X86_SYSFB 2822 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2823 help 2824 Firmwares often provide initial graphics framebuffers so the BIOS, 2825 bootloader or kernel can show basic video-output during boot for 2826 user-guidance and debugging. Historically, x86 used the VESA BIOS 2827 Extensions and EFI-framebuffers for this, which are mostly limited 2828 to x86. 2829 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2830 framebuffers so the new generic system-framebuffer drivers can be 2831 used on x86. If the framebuffer is not compatible with the generic 2832 modes, it is advertised as fallback platform framebuffer so legacy 2833 drivers like efifb, vesafb and uvesafb can pick it up. 2834 If this option is not selected, all system framebuffers are always 2835 marked as fallback platform framebuffers as usual. 2836 2837 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2838 not be able to pick up generic system framebuffers if this option 2839 is selected. You are highly encouraged to enable simplefb as 2840 replacement if you select this option. simplefb can correctly deal 2841 with generic system framebuffers. But you should still keep vesafb 2842 and others enabled as fallback if a system framebuffer is 2843 incompatible with simplefb. 2844 2845 If unsure, say Y. 2846 2847endmenu 2848 2849 2850menu "Binary Emulations" 2851 2852config IA32_EMULATION 2853 bool "IA32 Emulation" 2854 depends on X86_64 2855 select ARCH_WANT_OLD_COMPAT_IPC 2856 select BINFMT_ELF 2857 select COMPAT_BINFMT_ELF 2858 select COMPAT_OLD_SIGACTION 2859 help 2860 Include code to run legacy 32-bit programs under a 2861 64-bit kernel. You should likely turn this on, unless you're 2862 100% sure that you don't have any 32-bit programs left. 2863 2864config IA32_AOUT 2865 tristate "IA32 a.out support" 2866 depends on IA32_EMULATION 2867 depends on BROKEN 2868 help 2869 Support old a.out binaries in the 32bit emulation. 2870 2871config X86_X32 2872 bool "x32 ABI for 64-bit mode" 2873 depends on X86_64 2874 help 2875 Include code to run binaries for the x32 native 32-bit ABI 2876 for 64-bit processors. An x32 process gets access to the 2877 full 64-bit register file and wide data path while leaving 2878 pointers at 32 bits for smaller memory footprint. 2879 2880 You will need a recent binutils (2.22 or later) with 2881 elf32_x86_64 support enabled to compile a kernel with this 2882 option set. 2883 2884config COMPAT_32 2885 def_bool y 2886 depends on IA32_EMULATION || X86_32 2887 select HAVE_UID16 2888 select OLD_SIGSUSPEND3 2889 2890config COMPAT 2891 def_bool y 2892 depends on IA32_EMULATION || X86_X32 2893 2894if COMPAT 2895config COMPAT_FOR_U64_ALIGNMENT 2896 def_bool y 2897 2898config SYSVIPC_COMPAT 2899 def_bool y 2900 depends on SYSVIPC 2901endif 2902 2903endmenu 2904 2905 2906config HAVE_ATOMIC_IOMAP 2907 def_bool y 2908 depends on X86_32 2909 2910source "drivers/firmware/Kconfig" 2911 2912source "arch/x86/kvm/Kconfig" 2913 2914source "arch/x86/Kconfig.assembler" 2915