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_FIND_FIRST_BIT 119 select GENERIC_IOMAP 120 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 121 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 122 select GENERIC_IRQ_MIGRATION if SMP 123 select GENERIC_IRQ_PROBE 124 select GENERIC_IRQ_RESERVATION_MODE 125 select GENERIC_IRQ_SHOW 126 select GENERIC_PENDING_IRQ if SMP 127 select GENERIC_PTDUMP 128 select GENERIC_SMP_IDLE_THREAD 129 select GENERIC_STRNCPY_FROM_USER 130 select GENERIC_STRNLEN_USER 131 select GENERIC_TIME_VSYSCALL 132 select GENERIC_GETTIMEOFDAY 133 select GENERIC_VDSO_TIME_NS 134 select GUP_GET_PTE_LOW_HIGH if X86_PAE 135 select HARDIRQS_SW_RESEND 136 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 137 select HAVE_ACPI_APEI if ACPI 138 select HAVE_ACPI_APEI_NMI if ACPI 139 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 140 select HAVE_ARCH_AUDITSYSCALL 141 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 142 select HAVE_ARCH_JUMP_LABEL 143 select HAVE_ARCH_JUMP_LABEL_RELATIVE 144 select HAVE_ARCH_KASAN if X86_64 145 select HAVE_ARCH_KASAN_VMALLOC if X86_64 146 select HAVE_ARCH_KGDB 147 select HAVE_ARCH_MMAP_RND_BITS if MMU 148 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 149 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 150 select HAVE_ARCH_PREL32_RELOCATIONS 151 select HAVE_ARCH_SECCOMP_FILTER 152 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 153 select HAVE_ARCH_STACKLEAK 154 select HAVE_ARCH_TRACEHOOK 155 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 156 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 157 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 158 select HAVE_ARCH_VMAP_STACK if X86_64 159 select HAVE_ARCH_WITHIN_STACK_FRAMES 160 select HAVE_ASM_MODVERSIONS 161 select HAVE_CMPXCHG_DOUBLE 162 select HAVE_CMPXCHG_LOCAL 163 select HAVE_CONTEXT_TRACKING if X86_64 164 select HAVE_COPY_THREAD_TLS 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_KPROBES 192 select HAVE_KPROBES_ON_FTRACE 193 select HAVE_FUNCTION_ERROR_INJECTION 194 select HAVE_KRETPROBES 195 select HAVE_KVM 196 select HAVE_LIVEPATCH if X86_64 197 select HAVE_MIXED_BREAKPOINTS_REGS 198 select HAVE_MOD_ARCH_SPECIFIC 199 select HAVE_MOVE_PMD 200 select HAVE_NMI 201 select HAVE_OPROFILE 202 select HAVE_OPTPROBES 203 select HAVE_PCSPKR_PLATFORM 204 select HAVE_PERF_EVENTS 205 select HAVE_PERF_EVENTS_NMI 206 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 207 select HAVE_PCI 208 select HAVE_PERF_REGS 209 select HAVE_PERF_USER_STACK_DUMP 210 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 211 select HAVE_REGS_AND_STACK_ACCESS_API 212 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 213 select HAVE_FUNCTION_ARG_ACCESS_API 214 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 215 select HAVE_STACK_VALIDATION if X86_64 216 select HAVE_RSEQ 217 select HAVE_SYSCALL_TRACEPOINTS 218 select HAVE_UNSTABLE_SCHED_CLOCK 219 select HAVE_USER_RETURN_NOTIFIER 220 select HAVE_GENERIC_VDSO 221 select HOTPLUG_SMT if SMP 222 select IRQ_FORCED_THREADING 223 select NEED_SG_DMA_LENGTH 224 select PCI_DOMAINS if PCI 225 select PCI_LOCKLESS_CONFIG if PCI 226 select PERF_EVENTS 227 select RTC_LIB 228 select RTC_MC146818_LIB 229 select SPARSE_IRQ 230 select SRCU 231 select SYSCTL_EXCEPTION_TRACE 232 select THREAD_INFO_IN_TASK 233 select USER_STACKTRACE_SUPPORT 234 select VIRT_TO_BUS 235 select HAVE_ARCH_KCSAN if X86_64 236 select X86_FEATURE_NAMES if PROC_FS 237 select PROC_PID_ARCH_STATUS if PROC_FS 238 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 239 240config INSTRUCTION_DECODER 241 def_bool y 242 depends on KPROBES || PERF_EVENTS || UPROBES 243 244config OUTPUT_FORMAT 245 string 246 default "elf32-i386" if X86_32 247 default "elf64-x86-64" if X86_64 248 249config LOCKDEP_SUPPORT 250 def_bool y 251 252config STACKTRACE_SUPPORT 253 def_bool y 254 255config MMU 256 def_bool y 257 258config ARCH_MMAP_RND_BITS_MIN 259 default 28 if 64BIT 260 default 8 261 262config ARCH_MMAP_RND_BITS_MAX 263 default 32 if 64BIT 264 default 16 265 266config ARCH_MMAP_RND_COMPAT_BITS_MIN 267 default 8 268 269config ARCH_MMAP_RND_COMPAT_BITS_MAX 270 default 16 271 272config SBUS 273 bool 274 275config GENERIC_ISA_DMA 276 def_bool y 277 depends on ISA_DMA_API 278 279config GENERIC_BUG 280 def_bool y 281 depends on BUG 282 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 283 284config GENERIC_BUG_RELATIVE_POINTERS 285 bool 286 287config ARCH_MAY_HAVE_PC_FDC 288 def_bool y 289 depends on ISA_DMA_API 290 291config GENERIC_CALIBRATE_DELAY 292 def_bool y 293 294config ARCH_HAS_CPU_RELAX 295 def_bool y 296 297config ARCH_HAS_CACHE_LINE_SIZE 298 def_bool y 299 300config ARCH_HAS_FILTER_PGPROT 301 def_bool y 302 303config HAVE_SETUP_PER_CPU_AREA 304 def_bool y 305 306config NEED_PER_CPU_EMBED_FIRST_CHUNK 307 def_bool y 308 309config NEED_PER_CPU_PAGE_FIRST_CHUNK 310 def_bool y 311 312config ARCH_HIBERNATION_POSSIBLE 313 def_bool y 314 315config ARCH_SUSPEND_POSSIBLE 316 def_bool y 317 318config ARCH_WANT_GENERAL_HUGETLB 319 def_bool y 320 321config ZONE_DMA32 322 def_bool y if X86_64 323 324config AUDIT_ARCH 325 def_bool y if X86_64 326 327config ARCH_SUPPORTS_DEBUG_PAGEALLOC 328 def_bool y 329 330config KASAN_SHADOW_OFFSET 331 hex 332 depends on KASAN 333 default 0xdffffc0000000000 334 335config HAVE_INTEL_TXT 336 def_bool y 337 depends on INTEL_IOMMU && ACPI 338 339config X86_32_SMP 340 def_bool y 341 depends on X86_32 && SMP 342 343config X86_64_SMP 344 def_bool y 345 depends on X86_64 && SMP 346 347config X86_32_LAZY_GS 348 def_bool y 349 depends on X86_32 && !STACKPROTECTOR 350 351config ARCH_SUPPORTS_UPROBES 352 def_bool y 353 354config FIX_EARLYCON_MEM 355 def_bool y 356 357config DYNAMIC_PHYSICAL_MASK 358 bool 359 360config PGTABLE_LEVELS 361 int 362 default 5 if X86_5LEVEL 363 default 4 if X86_64 364 default 3 if X86_PAE 365 default 2 366 367config CC_HAS_SANE_STACKPROTECTOR 368 bool 369 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 370 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 371 help 372 We have to make sure stack protector is unconditionally disabled if 373 the compiler produces broken code. 374 375menu "Processor type and features" 376 377config ZONE_DMA 378 bool "DMA memory allocation support" if EXPERT 379 default y 380 help 381 DMA memory allocation support allows devices with less than 32-bit 382 addressing to allocate within the first 16MB of address space. 383 Disable if no such devices will be used. 384 385 If unsure, say Y. 386 387config SMP 388 bool "Symmetric multi-processing support" 389 help 390 This enables support for systems with more than one CPU. If you have 391 a system with only one CPU, say N. If you have a system with more 392 than one CPU, say Y. 393 394 If you say N here, the kernel will run on uni- and multiprocessor 395 machines, but will use only one CPU of a multiprocessor machine. If 396 you say Y here, the kernel will run on many, but not all, 397 uniprocessor machines. On a uniprocessor machine, the kernel 398 will run faster if you say N here. 399 400 Note that if you say Y here and choose architecture "586" or 401 "Pentium" under "Processor family", the kernel will not work on 486 402 architectures. Similarly, multiprocessor kernels for the "PPro" 403 architecture may not work on all Pentium based boards. 404 405 People using multiprocessor machines who say Y here should also say 406 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 407 Management" code will be disabled if you say Y here. 408 409 See also <file:Documentation/x86/i386/IO-APIC.rst>, 410 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 411 <http://www.tldp.org/docs.html#howto>. 412 413 If you don't know what to do here, say N. 414 415config X86_FEATURE_NAMES 416 bool "Processor feature human-readable names" if EMBEDDED 417 default y 418 help 419 This option compiles in a table of x86 feature bits and corresponding 420 names. This is required to support /proc/cpuinfo and a few kernel 421 messages. You can disable this to save space, at the expense of 422 making those few kernel messages show numeric feature bits instead. 423 424 If in doubt, say Y. 425 426config X86_X2APIC 427 bool "Support x2apic" 428 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 429 help 430 This enables x2apic support on CPUs that have this feature. 431 432 This allows 32-bit apic IDs (so it can support very large systems), 433 and accesses the local apic via MSRs not via mmio. 434 435 If you don't know what to do here, say N. 436 437config X86_MPPARSE 438 bool "Enable MPS table" if ACPI || SFI 439 default y 440 depends on X86_LOCAL_APIC 441 help 442 For old smp systems that do not have proper acpi support. Newer systems 443 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 444 445config GOLDFISH 446 def_bool y 447 depends on X86_GOLDFISH 448 449config RETPOLINE 450 bool "Avoid speculative indirect branches in kernel" 451 default y 452 select STACK_VALIDATION if HAVE_STACK_VALIDATION 453 help 454 Compile kernel with the retpoline compiler options to guard against 455 kernel-to-user data leaks by avoiding speculative indirect 456 branches. Requires a compiler with -mindirect-branch=thunk-extern 457 support for full protection. The kernel may run slower. 458 459config X86_CPU_RESCTRL 460 bool "x86 CPU resource control support" 461 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 462 select KERNFS 463 select PROC_CPU_RESCTRL if PROC_FS 464 help 465 Enable x86 CPU resource control support. 466 467 Provide support for the allocation and monitoring of system resources 468 usage by the CPU. 469 470 Intel calls this Intel Resource Director Technology 471 (Intel(R) RDT). More information about RDT can be found in the 472 Intel x86 Architecture Software Developer Manual. 473 474 AMD calls this AMD Platform Quality of Service (AMD QoS). 475 More information about AMD QoS can be found in the AMD64 Technology 476 Platform Quality of Service Extensions manual. 477 478 Say N if unsure. 479 480if X86_32 481config X86_BIGSMP 482 bool "Support for big SMP systems with more than 8 CPUs" 483 depends on SMP 484 help 485 This option is needed for the systems that have more than 8 CPUs. 486 487config X86_EXTENDED_PLATFORM 488 bool "Support for extended (non-PC) x86 platforms" 489 default y 490 help 491 If you disable this option then the kernel will only support 492 standard PC platforms. (which covers the vast majority of 493 systems out there.) 494 495 If you enable this option then you'll be able to select support 496 for the following (non-PC) 32 bit x86 platforms: 497 Goldfish (Android emulator) 498 AMD Elan 499 RDC R-321x SoC 500 SGI 320/540 (Visual Workstation) 501 STA2X11-based (e.g. Northville) 502 Moorestown MID devices 503 504 If you have one of these systems, or if you want to build a 505 generic distribution kernel, say Y here - otherwise say N. 506endif 507 508if X86_64 509config X86_EXTENDED_PLATFORM 510 bool "Support for extended (non-PC) x86 platforms" 511 default y 512 help 513 If you disable this option then the kernel will only support 514 standard PC platforms. (which covers the vast majority of 515 systems out there.) 516 517 If you enable this option then you'll be able to select support 518 for the following (non-PC) 64 bit x86 platforms: 519 Numascale NumaChip 520 ScaleMP vSMP 521 SGI Ultraviolet 522 523 If you have one of these systems, or if you want to build a 524 generic distribution kernel, say Y here - otherwise say N. 525endif 526# This is an alphabetically sorted list of 64 bit extended platforms 527# Please maintain the alphabetic order if and when there are additions 528config X86_NUMACHIP 529 bool "Numascale NumaChip" 530 depends on X86_64 531 depends on X86_EXTENDED_PLATFORM 532 depends on NUMA 533 depends on SMP 534 depends on X86_X2APIC 535 depends on PCI_MMCONFIG 536 help 537 Adds support for Numascale NumaChip large-SMP systems. Needed to 538 enable more than ~168 cores. 539 If you don't have one of these, you should say N here. 540 541config X86_VSMP 542 bool "ScaleMP vSMP" 543 select HYPERVISOR_GUEST 544 select PARAVIRT 545 depends on X86_64 && PCI 546 depends on X86_EXTENDED_PLATFORM 547 depends on SMP 548 help 549 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 550 supposed to run on these EM64T-based machines. Only choose this option 551 if you have one of these machines. 552 553config X86_UV 554 bool "SGI Ultraviolet" 555 depends on X86_64 556 depends on X86_EXTENDED_PLATFORM 557 depends on NUMA 558 depends on EFI 559 depends on X86_X2APIC 560 depends on PCI 561 help 562 This option is needed in order to support SGI Ultraviolet systems. 563 If you don't have one of these, you should say N here. 564 565# Following is an alphabetically sorted list of 32 bit extended platforms 566# Please maintain the alphabetic order if and when there are additions 567 568config X86_GOLDFISH 569 bool "Goldfish (Virtual Platform)" 570 depends on X86_EXTENDED_PLATFORM 571 help 572 Enable support for the Goldfish virtual platform used primarily 573 for Android development. Unless you are building for the Android 574 Goldfish emulator say N here. 575 576config X86_INTEL_CE 577 bool "CE4100 TV platform" 578 depends on PCI 579 depends on PCI_GODIRECT 580 depends on X86_IO_APIC 581 depends on X86_32 582 depends on X86_EXTENDED_PLATFORM 583 select X86_REBOOTFIXUPS 584 select OF 585 select OF_EARLY_FLATTREE 586 help 587 Select for the Intel CE media processor (CE4100) SOC. 588 This option compiles in support for the CE4100 SOC for settop 589 boxes and media devices. 590 591config X86_INTEL_MID 592 bool "Intel MID platform support" 593 depends on X86_EXTENDED_PLATFORM 594 depends on X86_PLATFORM_DEVICES 595 depends on PCI 596 depends on X86_64 || (PCI_GOANY && X86_32) 597 depends on X86_IO_APIC 598 select SFI 599 select I2C 600 select DW_APB_TIMER 601 select APB_TIMER 602 select INTEL_SCU_PCI 603 select MFD_INTEL_MSIC 604 help 605 Select to build a kernel capable of supporting Intel MID (Mobile 606 Internet Device) platform systems which do not have the PCI legacy 607 interfaces. If you are building for a PC class system say N here. 608 609 Intel MID platforms are based on an Intel processor and chipset which 610 consume less power than most of the x86 derivatives. 611 612config X86_INTEL_QUARK 613 bool "Intel Quark platform support" 614 depends on X86_32 615 depends on X86_EXTENDED_PLATFORM 616 depends on X86_PLATFORM_DEVICES 617 depends on X86_TSC 618 depends on PCI 619 depends on PCI_GOANY 620 depends on X86_IO_APIC 621 select IOSF_MBI 622 select INTEL_IMR 623 select COMMON_CLK 624 help 625 Select to include support for Quark X1000 SoC. 626 Say Y here if you have a Quark based system such as the Arduino 627 compatible Intel Galileo. 628 629config X86_INTEL_LPSS 630 bool "Intel Low Power Subsystem Support" 631 depends on X86 && ACPI && PCI 632 select COMMON_CLK 633 select PINCTRL 634 select IOSF_MBI 635 help 636 Select to build support for Intel Low Power Subsystem such as 637 found on Intel Lynxpoint PCH. Selecting this option enables 638 things like clock tree (common clock framework) and pincontrol 639 which are needed by the LPSS peripheral drivers. 640 641config X86_AMD_PLATFORM_DEVICE 642 bool "AMD ACPI2Platform devices support" 643 depends on ACPI 644 select COMMON_CLK 645 select PINCTRL 646 help 647 Select to interpret AMD specific ACPI device to platform device 648 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 649 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 650 implemented under PINCTRL subsystem. 651 652config IOSF_MBI 653 tristate "Intel SoC IOSF Sideband support for SoC platforms" 654 depends on PCI 655 help 656 This option enables sideband register access support for Intel SoC 657 platforms. On these platforms the IOSF sideband is used in lieu of 658 MSR's for some register accesses, mostly but not limited to thermal 659 and power. Drivers may query the availability of this device to 660 determine if they need the sideband in order to work on these 661 platforms. The sideband is available on the following SoC products. 662 This list is not meant to be exclusive. 663 - BayTrail 664 - Braswell 665 - Quark 666 667 You should say Y if you are running a kernel on one of these SoC's. 668 669config IOSF_MBI_DEBUG 670 bool "Enable IOSF sideband access through debugfs" 671 depends on IOSF_MBI && DEBUG_FS 672 help 673 Select this option to expose the IOSF sideband access registers (MCR, 674 MDR, MCRX) through debugfs to write and read register information from 675 different units on the SoC. This is most useful for obtaining device 676 state information for debug and analysis. As this is a general access 677 mechanism, users of this option would have specific knowledge of the 678 device they want to access. 679 680 If you don't require the option or are in doubt, say N. 681 682config X86_RDC321X 683 bool "RDC R-321x SoC" 684 depends on X86_32 685 depends on X86_EXTENDED_PLATFORM 686 select M486 687 select X86_REBOOTFIXUPS 688 help 689 This option is needed for RDC R-321x system-on-chip, also known 690 as R-8610-(G). 691 If you don't have one of these chips, you should say N here. 692 693config X86_32_NON_STANDARD 694 bool "Support non-standard 32-bit SMP architectures" 695 depends on X86_32 && SMP 696 depends on X86_EXTENDED_PLATFORM 697 help 698 This option compiles in the bigsmp and STA2X11 default 699 subarchitectures. It is intended for a generic binary 700 kernel. If you select them all, kernel will probe it one by 701 one and will fallback to default. 702 703# Alphabetically sorted list of Non standard 32 bit platforms 704 705config X86_SUPPORTS_MEMORY_FAILURE 706 def_bool y 707 # MCE code calls memory_failure(): 708 depends on X86_MCE 709 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 710 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 711 depends on X86_64 || !SPARSEMEM 712 select ARCH_SUPPORTS_MEMORY_FAILURE 713 714config STA2X11 715 bool "STA2X11 Companion Chip Support" 716 depends on X86_32_NON_STANDARD && PCI 717 select SWIOTLB 718 select MFD_STA2X11 719 select GPIOLIB 720 help 721 This adds support for boards based on the STA2X11 IO-Hub, 722 a.k.a. "ConneXt". The chip is used in place of the standard 723 PC chipset, so all "standard" peripherals are missing. If this 724 option is selected the kernel will still be able to boot on 725 standard PC machines. 726 727config X86_32_IRIS 728 tristate "Eurobraille/Iris poweroff module" 729 depends on X86_32 730 help 731 The Iris machines from EuroBraille do not have APM or ACPI support 732 to shut themselves down properly. A special I/O sequence is 733 needed to do so, which is what this module does at 734 kernel shutdown. 735 736 This is only for Iris machines from EuroBraille. 737 738 If unused, say N. 739 740config SCHED_OMIT_FRAME_POINTER 741 def_bool y 742 prompt "Single-depth WCHAN output" 743 depends on X86 744 help 745 Calculate simpler /proc/<PID>/wchan values. If this option 746 is disabled then wchan values will recurse back to the 747 caller function. This provides more accurate wchan values, 748 at the expense of slightly more scheduling overhead. 749 750 If in doubt, say "Y". 751 752menuconfig HYPERVISOR_GUEST 753 bool "Linux guest support" 754 help 755 Say Y here to enable options for running Linux under various hyper- 756 visors. This option enables basic hypervisor detection and platform 757 setup. 758 759 If you say N, all options in this submenu will be skipped and 760 disabled, and Linux guest support won't be built in. 761 762if HYPERVISOR_GUEST 763 764config PARAVIRT 765 bool "Enable paravirtualization code" 766 help 767 This changes the kernel so it can modify itself when it is run 768 under a hypervisor, potentially improving performance significantly 769 over full virtualization. However, when run without a hypervisor 770 the kernel is theoretically slower and slightly larger. 771 772config PARAVIRT_XXL 773 bool 774 775config PARAVIRT_DEBUG 776 bool "paravirt-ops debugging" 777 depends on PARAVIRT && DEBUG_KERNEL 778 help 779 Enable to debug paravirt_ops internals. Specifically, BUG if 780 a paravirt_op is missing when it is called. 781 782config PARAVIRT_SPINLOCKS 783 bool "Paravirtualization layer for spinlocks" 784 depends on PARAVIRT && SMP 785 help 786 Paravirtualized spinlocks allow a pvops backend to replace the 787 spinlock implementation with something virtualization-friendly 788 (for example, block the virtual CPU rather than spinning). 789 790 It has a minimal impact on native kernels and gives a nice performance 791 benefit on paravirtualized KVM / Xen kernels. 792 793 If you are unsure how to answer this question, answer Y. 794 795config X86_HV_CALLBACK_VECTOR 796 def_bool n 797 798source "arch/x86/xen/Kconfig" 799 800config KVM_GUEST 801 bool "KVM Guest support (including kvmclock)" 802 depends on PARAVIRT 803 select PARAVIRT_CLOCK 804 select ARCH_CPUIDLE_HALTPOLL 805 default y 806 help 807 This option enables various optimizations for running under the KVM 808 hypervisor. It includes a paravirtualized clock, so that instead 809 of relying on a PIT (or probably other) emulation by the 810 underlying device model, the host provides the guest with 811 timing infrastructure such as time of day, and system time 812 813config ARCH_CPUIDLE_HALTPOLL 814 def_bool n 815 prompt "Disable host haltpoll when loading haltpoll driver" 816 help 817 If virtualized under KVM, disable host haltpoll. 818 819config PVH 820 bool "Support for running PVH guests" 821 help 822 This option enables the PVH entry point for guest virtual machines 823 as specified in the x86/HVM direct boot ABI. 824 825config PARAVIRT_TIME_ACCOUNTING 826 bool "Paravirtual steal time accounting" 827 depends on PARAVIRT 828 help 829 Select this option to enable fine granularity task steal time 830 accounting. Time spent executing other tasks in parallel with 831 the current vCPU is discounted from the vCPU power. To account for 832 that, there can be a small performance impact. 833 834 If in doubt, say N here. 835 836config PARAVIRT_CLOCK 837 bool 838 839config JAILHOUSE_GUEST 840 bool "Jailhouse non-root cell support" 841 depends on X86_64 && PCI 842 select X86_PM_TIMER 843 help 844 This option allows to run Linux as guest in a Jailhouse non-root 845 cell. You can leave this option disabled if you only want to start 846 Jailhouse and run Linux afterwards in the root cell. 847 848config ACRN_GUEST 849 bool "ACRN Guest support" 850 depends on X86_64 851 select X86_HV_CALLBACK_VECTOR 852 help 853 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 854 a flexible, lightweight reference open-source hypervisor, built with 855 real-time and safety-criticality in mind. It is built for embedded 856 IOT with small footprint and real-time features. More details can be 857 found in https://projectacrn.org/. 858 859endif #HYPERVISOR_GUEST 860 861source "arch/x86/Kconfig.cpu" 862 863config HPET_TIMER 864 def_bool X86_64 865 prompt "HPET Timer Support" if X86_32 866 help 867 Use the IA-PC HPET (High Precision Event Timer) to manage 868 time in preference to the PIT and RTC, if a HPET is 869 present. 870 HPET is the next generation timer replacing legacy 8254s. 871 The HPET provides a stable time base on SMP 872 systems, unlike the TSC, but it is more expensive to access, 873 as it is off-chip. The interface used is documented 874 in the HPET spec, revision 1. 875 876 You can safely choose Y here. However, HPET will only be 877 activated if the platform and the BIOS support this feature. 878 Otherwise the 8254 will be used for timing services. 879 880 Choose N to continue using the legacy 8254 timer. 881 882config HPET_EMULATE_RTC 883 def_bool y 884 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 885 886config APB_TIMER 887 def_bool y if X86_INTEL_MID 888 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 889 select DW_APB_TIMER 890 depends on X86_INTEL_MID && SFI 891 help 892 APB timer is the replacement for 8254, HPET on X86 MID platforms. 893 The APBT provides a stable time base on SMP 894 systems, unlike the TSC, but it is more expensive to access, 895 as it is off-chip. APB timers are always running regardless of CPU 896 C states, they are used as per CPU clockevent device when possible. 897 898# Mark as expert because too many people got it wrong. 899# The code disables itself when not needed. 900config DMI 901 default y 902 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 903 bool "Enable DMI scanning" if EXPERT 904 help 905 Enabled scanning of DMI to identify machine quirks. Say Y 906 here unless you have verified that your setup is not 907 affected by entries in the DMI blacklist. Required by PNP 908 BIOS code. 909 910config GART_IOMMU 911 bool "Old AMD GART IOMMU support" 912 select IOMMU_HELPER 913 select SWIOTLB 914 depends on X86_64 && PCI && AMD_NB 915 help 916 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 917 GART based hardware IOMMUs. 918 919 The GART supports full DMA access for devices with 32-bit access 920 limitations, on systems with more than 3 GB. This is usually needed 921 for USB, sound, many IDE/SATA chipsets and some other devices. 922 923 Newer systems typically have a modern AMD IOMMU, supported via 924 the CONFIG_AMD_IOMMU=y config option. 925 926 In normal configurations this driver is only active when needed: 927 there's more than 3 GB of memory and the system contains a 928 32-bit limited device. 929 930 If unsure, say Y. 931 932config MAXSMP 933 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 934 depends on X86_64 && SMP && DEBUG_KERNEL 935 select CPUMASK_OFFSTACK 936 help 937 Enable maximum number of CPUS and NUMA Nodes for this architecture. 938 If unsure, say N. 939 940# 941# The maximum number of CPUs supported: 942# 943# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 944# and which can be configured interactively in the 945# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 946# 947# The ranges are different on 32-bit and 64-bit kernels, depending on 948# hardware capabilities and scalability features of the kernel. 949# 950# ( If MAXSMP is enabled we just use the highest possible value and disable 951# interactive configuration. ) 952# 953 954config NR_CPUS_RANGE_BEGIN 955 int 956 default NR_CPUS_RANGE_END if MAXSMP 957 default 1 if !SMP 958 default 2 959 960config NR_CPUS_RANGE_END 961 int 962 depends on X86_32 963 default 64 if SMP && X86_BIGSMP 964 default 8 if SMP && !X86_BIGSMP 965 default 1 if !SMP 966 967config NR_CPUS_RANGE_END 968 int 969 depends on X86_64 970 default 8192 if SMP && CPUMASK_OFFSTACK 971 default 512 if SMP && !CPUMASK_OFFSTACK 972 default 1 if !SMP 973 974config NR_CPUS_DEFAULT 975 int 976 depends on X86_32 977 default 32 if X86_BIGSMP 978 default 8 if SMP 979 default 1 if !SMP 980 981config NR_CPUS_DEFAULT 982 int 983 depends on X86_64 984 default 8192 if MAXSMP 985 default 64 if SMP 986 default 1 if !SMP 987 988config NR_CPUS 989 int "Maximum number of CPUs" if SMP && !MAXSMP 990 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 991 default NR_CPUS_DEFAULT 992 help 993 This allows you to specify the maximum number of CPUs which this 994 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 995 supported value is 8192, otherwise the maximum value is 512. The 996 minimum value which makes sense is 2. 997 998 This is purely to save memory: each supported CPU adds about 8KB 999 to the kernel image. 1000 1001config SCHED_SMT 1002 def_bool y if SMP 1003 1004config SCHED_MC 1005 def_bool y 1006 prompt "Multi-core scheduler support" 1007 depends on SMP 1008 help 1009 Multi-core scheduler support improves the CPU scheduler's decision 1010 making when dealing with multi-core CPU chips at a cost of slightly 1011 increased overhead in some places. If unsure say N here. 1012 1013config SCHED_MC_PRIO 1014 bool "CPU core priorities scheduler support" 1015 depends on SCHED_MC && CPU_SUP_INTEL 1016 select X86_INTEL_PSTATE 1017 select CPU_FREQ 1018 default y 1019 help 1020 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1021 core ordering determined at manufacturing time, which allows 1022 certain cores to reach higher turbo frequencies (when running 1023 single threaded workloads) than others. 1024 1025 Enabling this kernel feature teaches the scheduler about 1026 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1027 scheduler's CPU selection logic accordingly, so that higher 1028 overall system performance can be achieved. 1029 1030 This feature will have no effect on CPUs without this feature. 1031 1032 If unsure say Y here. 1033 1034config UP_LATE_INIT 1035 def_bool y 1036 depends on !SMP && X86_LOCAL_APIC 1037 1038config X86_UP_APIC 1039 bool "Local APIC support on uniprocessors" if !PCI_MSI 1040 default PCI_MSI 1041 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1042 help 1043 A local APIC (Advanced Programmable Interrupt Controller) is an 1044 integrated interrupt controller in the CPU. If you have a single-CPU 1045 system which has a processor with a local APIC, you can say Y here to 1046 enable and use it. If you say Y here even though your machine doesn't 1047 have a local APIC, then the kernel will still run with no slowdown at 1048 all. The local APIC supports CPU-generated self-interrupts (timer, 1049 performance counters), and the NMI watchdog which detects hard 1050 lockups. 1051 1052config X86_UP_IOAPIC 1053 bool "IO-APIC support on uniprocessors" 1054 depends on X86_UP_APIC 1055 help 1056 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1057 SMP-capable replacement for PC-style interrupt controllers. Most 1058 SMP systems and many recent uniprocessor systems have one. 1059 1060 If you have a single-CPU system with an IO-APIC, you can say Y here 1061 to use it. If you say Y here even though your machine doesn't have 1062 an IO-APIC, then the kernel will still run with no slowdown at all. 1063 1064config X86_LOCAL_APIC 1065 def_bool y 1066 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1067 select IRQ_DOMAIN_HIERARCHY 1068 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1069 1070config X86_IO_APIC 1071 def_bool y 1072 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1073 1074config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1075 bool "Reroute for broken boot IRQs" 1076 depends on X86_IO_APIC 1077 help 1078 This option enables a workaround that fixes a source of 1079 spurious interrupts. This is recommended when threaded 1080 interrupt handling is used on systems where the generation of 1081 superfluous "boot interrupts" cannot be disabled. 1082 1083 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1084 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1085 kernel does during interrupt handling). On chipsets where this 1086 boot IRQ generation cannot be disabled, this workaround keeps 1087 the original IRQ line masked so that only the equivalent "boot 1088 IRQ" is delivered to the CPUs. The workaround also tells the 1089 kernel to set up the IRQ handler on the boot IRQ line. In this 1090 way only one interrupt is delivered to the kernel. Otherwise 1091 the spurious second interrupt may cause the kernel to bring 1092 down (vital) interrupt lines. 1093 1094 Only affects "broken" chipsets. Interrupt sharing may be 1095 increased on these systems. 1096 1097config X86_MCE 1098 bool "Machine Check / overheating reporting" 1099 select GENERIC_ALLOCATOR 1100 default y 1101 help 1102 Machine Check support allows the processor to notify the 1103 kernel if it detects a problem (e.g. overheating, data corruption). 1104 The action the kernel takes depends on the severity of the problem, 1105 ranging from warning messages to halting the machine. 1106 1107config X86_MCELOG_LEGACY 1108 bool "Support for deprecated /dev/mcelog character device" 1109 depends on X86_MCE 1110 help 1111 Enable support for /dev/mcelog which is needed by the old mcelog 1112 userspace logging daemon. Consider switching to the new generation 1113 rasdaemon solution. 1114 1115config X86_MCE_INTEL 1116 def_bool y 1117 prompt "Intel MCE features" 1118 depends on X86_MCE && X86_LOCAL_APIC 1119 help 1120 Additional support for intel specific MCE features such as 1121 the thermal monitor. 1122 1123config X86_MCE_AMD 1124 def_bool y 1125 prompt "AMD MCE features" 1126 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1127 help 1128 Additional support for AMD specific MCE features such as 1129 the DRAM Error Threshold. 1130 1131config X86_ANCIENT_MCE 1132 bool "Support for old Pentium 5 / WinChip machine checks" 1133 depends on X86_32 && X86_MCE 1134 help 1135 Include support for machine check handling on old Pentium 5 or WinChip 1136 systems. These typically need to be enabled explicitly on the command 1137 line. 1138 1139config X86_MCE_THRESHOLD 1140 depends on X86_MCE_AMD || X86_MCE_INTEL 1141 def_bool y 1142 1143config X86_MCE_INJECT 1144 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1145 tristate "Machine check injector support" 1146 help 1147 Provide support for injecting machine checks for testing purposes. 1148 If you don't know what a machine check is and you don't do kernel 1149 QA it is safe to say n. 1150 1151config X86_THERMAL_VECTOR 1152 def_bool y 1153 depends on X86_MCE_INTEL 1154 1155source "arch/x86/events/Kconfig" 1156 1157config X86_LEGACY_VM86 1158 bool "Legacy VM86 support" 1159 depends on X86_32 1160 help 1161 This option allows user programs to put the CPU into V8086 1162 mode, which is an 80286-era approximation of 16-bit real mode. 1163 1164 Some very old versions of X and/or vbetool require this option 1165 for user mode setting. Similarly, DOSEMU will use it if 1166 available to accelerate real mode DOS programs. However, any 1167 recent version of DOSEMU, X, or vbetool should be fully 1168 functional even without kernel VM86 support, as they will all 1169 fall back to software emulation. Nevertheless, if you are using 1170 a 16-bit DOS program where 16-bit performance matters, vm86 1171 mode might be faster than emulation and you might want to 1172 enable this option. 1173 1174 Note that any app that works on a 64-bit kernel is unlikely to 1175 need this option, as 64-bit kernels don't, and can't, support 1176 V8086 mode. This option is also unrelated to 16-bit protected 1177 mode and is not needed to run most 16-bit programs under Wine. 1178 1179 Enabling this option increases the complexity of the kernel 1180 and slows down exception handling a tiny bit. 1181 1182 If unsure, say N here. 1183 1184config VM86 1185 bool 1186 default X86_LEGACY_VM86 1187 1188config X86_16BIT 1189 bool "Enable support for 16-bit segments" if EXPERT 1190 default y 1191 depends on MODIFY_LDT_SYSCALL 1192 help 1193 This option is required by programs like Wine to run 16-bit 1194 protected mode legacy code on x86 processors. Disabling 1195 this option saves about 300 bytes on i386, or around 6K text 1196 plus 16K runtime memory on x86-64, 1197 1198config X86_ESPFIX32 1199 def_bool y 1200 depends on X86_16BIT && X86_32 1201 1202config X86_ESPFIX64 1203 def_bool y 1204 depends on X86_16BIT && X86_64 1205 1206config X86_VSYSCALL_EMULATION 1207 bool "Enable vsyscall emulation" if EXPERT 1208 default y 1209 depends on X86_64 1210 help 1211 This enables emulation of the legacy vsyscall page. Disabling 1212 it is roughly equivalent to booting with vsyscall=none, except 1213 that it will also disable the helpful warning if a program 1214 tries to use a vsyscall. With this option set to N, offending 1215 programs will just segfault, citing addresses of the form 1216 0xffffffffff600?00. 1217 1218 This option is required by many programs built before 2013, and 1219 care should be used even with newer programs if set to N. 1220 1221 Disabling this option saves about 7K of kernel size and 1222 possibly 4K of additional runtime pagetable memory. 1223 1224config X86_IOPL_IOPERM 1225 bool "IOPERM and IOPL Emulation" 1226 default y 1227 help 1228 This enables the ioperm() and iopl() syscalls which are necessary 1229 for legacy applications. 1230 1231 Legacy IOPL support is an overbroad mechanism which allows user 1232 space aside of accessing all 65536 I/O ports also to disable 1233 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1234 capabilities and permission from potentially active security 1235 modules. 1236 1237 The emulation restricts the functionality of the syscall to 1238 only allowing the full range I/O port access, but prevents the 1239 ability to disable interrupts from user space which would be 1240 granted if the hardware IOPL mechanism would be used. 1241 1242config TOSHIBA 1243 tristate "Toshiba Laptop support" 1244 depends on X86_32 1245 help 1246 This adds a driver to safely access the System Management Mode of 1247 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1248 not work on models with a Phoenix BIOS. The System Management Mode 1249 is used to set the BIOS and power saving options on Toshiba portables. 1250 1251 For information on utilities to make use of this driver see the 1252 Toshiba Linux utilities web site at: 1253 <http://www.buzzard.org.uk/toshiba/>. 1254 1255 Say Y if you intend to run this kernel on a Toshiba portable. 1256 Say N otherwise. 1257 1258config I8K 1259 tristate "Dell i8k legacy laptop support" 1260 select HWMON 1261 select SENSORS_DELL_SMM 1262 help 1263 This option enables legacy /proc/i8k userspace interface in hwmon 1264 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1265 temperature and allows controlling fan speeds of Dell laptops via 1266 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1267 it reports also power and hotkey status. For fan speed control is 1268 needed userspace package i8kutils. 1269 1270 Say Y if you intend to run this kernel on old Dell laptops or want to 1271 use userspace package i8kutils. 1272 Say N otherwise. 1273 1274config X86_REBOOTFIXUPS 1275 bool "Enable X86 board specific fixups for reboot" 1276 depends on X86_32 1277 help 1278 This enables chipset and/or board specific fixups to be done 1279 in order to get reboot to work correctly. This is only needed on 1280 some combinations of hardware and BIOS. The symptom, for which 1281 this config is intended, is when reboot ends with a stalled/hung 1282 system. 1283 1284 Currently, the only fixup is for the Geode machines using 1285 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1286 1287 Say Y if you want to enable the fixup. Currently, it's safe to 1288 enable this option even if you don't need it. 1289 Say N otherwise. 1290 1291config MICROCODE 1292 bool "CPU microcode loading support" 1293 default y 1294 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1295 select FW_LOADER 1296 help 1297 If you say Y here, you will be able to update the microcode on 1298 Intel and AMD processors. The Intel support is for the IA32 family, 1299 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1300 AMD support is for families 0x10 and later. You will obviously need 1301 the actual microcode binary data itself which is not shipped with 1302 the Linux kernel. 1303 1304 The preferred method to load microcode from a detached initrd is described 1305 in Documentation/x86/microcode.rst. For that you need to enable 1306 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1307 initrd for microcode blobs. 1308 1309 In addition, you can build the microcode into the kernel. For that you 1310 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1311 config option. 1312 1313config MICROCODE_INTEL 1314 bool "Intel microcode loading support" 1315 depends on MICROCODE 1316 default MICROCODE 1317 select FW_LOADER 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 select FW_LOADER 1330 help 1331 If you select this option, microcode patch loading support for AMD 1332 processors will be enabled. 1333 1334config MICROCODE_OLD_INTERFACE 1335 bool "Ancient loading interface (DEPRECATED)" 1336 default n 1337 depends on MICROCODE 1338 help 1339 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1340 which was used by userspace tools like iucode_tool and microcode.ctl. 1341 It is inadequate because it runs too late to be able to properly 1342 load microcode on a machine and it needs special tools. Instead, you 1343 should've switched to the early loading method with the initrd or 1344 builtin microcode by now: Documentation/x86/microcode.rst 1345 1346config X86_MSR 1347 tristate "/dev/cpu/*/msr - Model-specific register support" 1348 help 1349 This device gives privileged processes access to the x86 1350 Model-Specific Registers (MSRs). It is a character device with 1351 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1352 MSR accesses are directed to a specific CPU on multi-processor 1353 systems. 1354 1355config X86_CPUID 1356 tristate "/dev/cpu/*/cpuid - CPU information support" 1357 help 1358 This device gives processes access to the x86 CPUID instruction to 1359 be executed on a specific processor. It is a character device 1360 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1361 /dev/cpu/31/cpuid. 1362 1363choice 1364 prompt "High Memory Support" 1365 default HIGHMEM4G 1366 depends on X86_32 1367 1368config NOHIGHMEM 1369 bool "off" 1370 help 1371 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1372 However, the address space of 32-bit x86 processors is only 4 1373 Gigabytes large. That means that, if you have a large amount of 1374 physical memory, not all of it can be "permanently mapped" by the 1375 kernel. The physical memory that's not permanently mapped is called 1376 "high memory". 1377 1378 If you are compiling a kernel which will never run on a machine with 1379 more than 1 Gigabyte total physical RAM, answer "off" here (default 1380 choice and suitable for most users). This will result in a "3GB/1GB" 1381 split: 3GB are mapped so that each process sees a 3GB virtual memory 1382 space and the remaining part of the 4GB virtual memory space is used 1383 by the kernel to permanently map as much physical memory as 1384 possible. 1385 1386 If the machine has between 1 and 4 Gigabytes physical RAM, then 1387 answer "4GB" here. 1388 1389 If more than 4 Gigabytes is used then answer "64GB" here. This 1390 selection turns Intel PAE (Physical Address Extension) mode on. 1391 PAE implements 3-level paging on IA32 processors. PAE is fully 1392 supported by Linux, PAE mode is implemented on all recent Intel 1393 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1394 then the kernel will not boot on CPUs that don't support PAE! 1395 1396 The actual amount of total physical memory will either be 1397 auto detected or can be forced by using a kernel command line option 1398 such as "mem=256M". (Try "man bootparam" or see the documentation of 1399 your boot loader (lilo or loadlin) about how to pass options to the 1400 kernel at boot time.) 1401 1402 If unsure, say "off". 1403 1404config HIGHMEM4G 1405 bool "4GB" 1406 help 1407 Select this if you have a 32-bit processor and between 1 and 4 1408 gigabytes of physical RAM. 1409 1410config HIGHMEM64G 1411 bool "64GB" 1412 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1413 select X86_PAE 1414 help 1415 Select this if you have a 32-bit processor and more than 4 1416 gigabytes of physical RAM. 1417 1418endchoice 1419 1420choice 1421 prompt "Memory split" if EXPERT 1422 default VMSPLIT_3G 1423 depends on X86_32 1424 help 1425 Select the desired split between kernel and user memory. 1426 1427 If the address range available to the kernel is less than the 1428 physical memory installed, the remaining memory will be available 1429 as "high memory". Accessing high memory is a little more costly 1430 than low memory, as it needs to be mapped into the kernel first. 1431 Note that increasing the kernel address space limits the range 1432 available to user programs, making the address space there 1433 tighter. Selecting anything other than the default 3G/1G split 1434 will also likely make your kernel incompatible with binary-only 1435 kernel modules. 1436 1437 If you are not absolutely sure what you are doing, leave this 1438 option alone! 1439 1440 config VMSPLIT_3G 1441 bool "3G/1G user/kernel split" 1442 config VMSPLIT_3G_OPT 1443 depends on !X86_PAE 1444 bool "3G/1G user/kernel split (for full 1G low memory)" 1445 config VMSPLIT_2G 1446 bool "2G/2G user/kernel split" 1447 config VMSPLIT_2G_OPT 1448 depends on !X86_PAE 1449 bool "2G/2G user/kernel split (for full 2G low memory)" 1450 config VMSPLIT_1G 1451 bool "1G/3G user/kernel split" 1452endchoice 1453 1454config PAGE_OFFSET 1455 hex 1456 default 0xB0000000 if VMSPLIT_3G_OPT 1457 default 0x80000000 if VMSPLIT_2G 1458 default 0x78000000 if VMSPLIT_2G_OPT 1459 default 0x40000000 if VMSPLIT_1G 1460 default 0xC0000000 1461 depends on X86_32 1462 1463config HIGHMEM 1464 def_bool y 1465 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1466 1467config X86_PAE 1468 bool "PAE (Physical Address Extension) Support" 1469 depends on X86_32 && !HIGHMEM4G 1470 select PHYS_ADDR_T_64BIT 1471 select SWIOTLB 1472 help 1473 PAE is required for NX support, and furthermore enables 1474 larger swapspace support for non-overcommit purposes. It 1475 has the cost of more pagetable lookup overhead, and also 1476 consumes more pagetable space per process. 1477 1478config X86_5LEVEL 1479 bool "Enable 5-level page tables support" 1480 default y 1481 select DYNAMIC_MEMORY_LAYOUT 1482 select SPARSEMEM_VMEMMAP 1483 depends on X86_64 1484 help 1485 5-level paging enables access to larger address space: 1486 upto 128 PiB of virtual address space and 4 PiB of 1487 physical address space. 1488 1489 It will be supported by future Intel CPUs. 1490 1491 A kernel with the option enabled can be booted on machines that 1492 support 4- or 5-level paging. 1493 1494 See Documentation/x86/x86_64/5level-paging.rst for more 1495 information. 1496 1497 Say N if unsure. 1498 1499config X86_DIRECT_GBPAGES 1500 def_bool y 1501 depends on X86_64 1502 help 1503 Certain kernel features effectively disable kernel 1504 linear 1 GB mappings (even if the CPU otherwise 1505 supports them), so don't confuse the user by printing 1506 that we have them enabled. 1507 1508config X86_CPA_STATISTICS 1509 bool "Enable statistic for Change Page Attribute" 1510 depends on DEBUG_FS 1511 help 1512 Expose statistics about the Change Page Attribute mechanism, which 1513 helps to determine the effectiveness of preserving large and huge 1514 page mappings when mapping protections are changed. 1515 1516config AMD_MEM_ENCRYPT 1517 bool "AMD Secure Memory Encryption (SME) support" 1518 depends on X86_64 && CPU_SUP_AMD 1519 select DMA_COHERENT_POOL 1520 select DYNAMIC_PHYSICAL_MASK 1521 select ARCH_USE_MEMREMAP_PROT 1522 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1523 help 1524 Say yes to enable support for the encryption of system memory. 1525 This requires an AMD processor that supports Secure Memory 1526 Encryption (SME). 1527 1528config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1529 bool "Activate AMD Secure Memory Encryption (SME) by default" 1530 default y 1531 depends on AMD_MEM_ENCRYPT 1532 help 1533 Say yes to have system memory encrypted by default if running on 1534 an AMD processor that supports Secure Memory Encryption (SME). 1535 1536 If set to Y, then the encryption of system memory can be 1537 deactivated with the mem_encrypt=off command line option. 1538 1539 If set to N, then the encryption of system memory can be 1540 activated with the mem_encrypt=on command line option. 1541 1542# Common NUMA Features 1543config NUMA 1544 bool "NUMA Memory Allocation and Scheduler Support" 1545 depends on SMP 1546 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1547 default y if X86_BIGSMP 1548 help 1549 Enable NUMA (Non-Uniform Memory Access) support. 1550 1551 The kernel will try to allocate memory used by a CPU on the 1552 local memory controller of the CPU and add some more 1553 NUMA awareness to the kernel. 1554 1555 For 64-bit this is recommended if the system is Intel Core i7 1556 (or later), AMD Opteron, or EM64T NUMA. 1557 1558 For 32-bit this is only needed if you boot a 32-bit 1559 kernel on a 64-bit NUMA platform. 1560 1561 Otherwise, you should say N. 1562 1563config AMD_NUMA 1564 def_bool y 1565 prompt "Old style AMD Opteron NUMA detection" 1566 depends on X86_64 && NUMA && PCI 1567 help 1568 Enable AMD NUMA node topology detection. You should say Y here if 1569 you have a multi processor AMD system. This uses an old method to 1570 read the NUMA configuration directly from the builtin Northbridge 1571 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1572 which also takes priority if both are compiled in. 1573 1574config X86_64_ACPI_NUMA 1575 def_bool y 1576 prompt "ACPI NUMA detection" 1577 depends on X86_64 && NUMA && ACPI && PCI 1578 select ACPI_NUMA 1579 help 1580 Enable ACPI SRAT based node topology detection. 1581 1582config NUMA_EMU 1583 bool "NUMA emulation" 1584 depends on NUMA 1585 help 1586 Enable NUMA emulation. A flat machine will be split 1587 into virtual nodes when booted with "numa=fake=N", where N is the 1588 number of nodes. This is only useful for debugging. 1589 1590config NODES_SHIFT 1591 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1592 range 1 10 1593 default "10" if MAXSMP 1594 default "6" if X86_64 1595 default "3" 1596 depends on NEED_MULTIPLE_NODES 1597 help 1598 Specify the maximum number of NUMA Nodes available on the target 1599 system. Increases memory reserved to accommodate various tables. 1600 1601config ARCH_FLATMEM_ENABLE 1602 def_bool y 1603 depends on X86_32 && !NUMA 1604 1605config ARCH_SPARSEMEM_ENABLE 1606 def_bool y 1607 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1608 select SPARSEMEM_STATIC if X86_32 1609 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1610 1611config ARCH_SPARSEMEM_DEFAULT 1612 def_bool X86_64 || (NUMA && X86_32) 1613 1614config ARCH_SELECT_MEMORY_MODEL 1615 def_bool y 1616 depends on ARCH_SPARSEMEM_ENABLE 1617 1618config ARCH_MEMORY_PROBE 1619 bool "Enable sysfs memory/probe interface" 1620 depends on X86_64 && MEMORY_HOTPLUG 1621 help 1622 This option enables a sysfs memory/probe interface for testing. 1623 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1624 If you are unsure how to answer this question, answer N. 1625 1626config ARCH_PROC_KCORE_TEXT 1627 def_bool y 1628 depends on X86_64 && PROC_KCORE 1629 1630config ILLEGAL_POINTER_VALUE 1631 hex 1632 default 0 if X86_32 1633 default 0xdead000000000000 if X86_64 1634 1635config X86_PMEM_LEGACY_DEVICE 1636 bool 1637 1638config X86_PMEM_LEGACY 1639 tristate "Support non-standard NVDIMMs and ADR protected memory" 1640 depends on PHYS_ADDR_T_64BIT 1641 depends on BLK_DEV 1642 select X86_PMEM_LEGACY_DEVICE 1643 select NUMA_KEEP_MEMINFO if NUMA 1644 select LIBNVDIMM 1645 help 1646 Treat memory marked using the non-standard e820 type of 12 as used 1647 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1648 The kernel will offer these regions to the 'pmem' driver so 1649 they can be used for persistent storage. 1650 1651 Say Y if unsure. 1652 1653config HIGHPTE 1654 bool "Allocate 3rd-level pagetables from highmem" 1655 depends on HIGHMEM 1656 help 1657 The VM uses one page table entry for each page of physical memory. 1658 For systems with a lot of RAM, this can be wasteful of precious 1659 low memory. Setting this option will put user-space page table 1660 entries in high memory. 1661 1662config X86_CHECK_BIOS_CORRUPTION 1663 bool "Check for low memory corruption" 1664 help 1665 Periodically check for memory corruption in low memory, which 1666 is suspected to be caused by BIOS. Even when enabled in the 1667 configuration, it is disabled at runtime. Enable it by 1668 setting "memory_corruption_check=1" on the kernel command 1669 line. By default it scans the low 64k of memory every 60 1670 seconds; see the memory_corruption_check_size and 1671 memory_corruption_check_period parameters in 1672 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1673 1674 When enabled with the default parameters, this option has 1675 almost no overhead, as it reserves a relatively small amount 1676 of memory and scans it infrequently. It both detects corruption 1677 and prevents it from affecting the running system. 1678 1679 It is, however, intended as a diagnostic tool; if repeatable 1680 BIOS-originated corruption always affects the same memory, 1681 you can use memmap= to prevent the kernel from using that 1682 memory. 1683 1684config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1685 bool "Set the default setting of memory_corruption_check" 1686 depends on X86_CHECK_BIOS_CORRUPTION 1687 default y 1688 help 1689 Set whether the default state of memory_corruption_check is 1690 on or off. 1691 1692config X86_RESERVE_LOW 1693 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1694 default 64 1695 range 4 640 1696 help 1697 Specify the amount of low memory to reserve for the BIOS. 1698 1699 The first page contains BIOS data structures that the kernel 1700 must not use, so that page must always be reserved. 1701 1702 By default we reserve the first 64K of physical RAM, as a 1703 number of BIOSes are known to corrupt that memory range 1704 during events such as suspend/resume or monitor cable 1705 insertion, so it must not be used by the kernel. 1706 1707 You can set this to 4 if you are absolutely sure that you 1708 trust the BIOS to get all its memory reservations and usages 1709 right. If you know your BIOS have problems beyond the 1710 default 64K area, you can set this to 640 to avoid using the 1711 entire low memory range. 1712 1713 If you have doubts about the BIOS (e.g. suspend/resume does 1714 not work or there's kernel crashes after certain hardware 1715 hotplug events) then you might want to enable 1716 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1717 typical corruption patterns. 1718 1719 Leave this to the default value of 64 if you are unsure. 1720 1721config MATH_EMULATION 1722 bool 1723 depends on MODIFY_LDT_SYSCALL 1724 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1725 help 1726 Linux can emulate a math coprocessor (used for floating point 1727 operations) if you don't have one. 486DX and Pentium processors have 1728 a math coprocessor built in, 486SX and 386 do not, unless you added 1729 a 487DX or 387, respectively. (The messages during boot time can 1730 give you some hints here ["man dmesg"].) Everyone needs either a 1731 coprocessor or this emulation. 1732 1733 If you don't have a math coprocessor, you need to say Y here; if you 1734 say Y here even though you have a coprocessor, the coprocessor will 1735 be used nevertheless. (This behavior can be changed with the kernel 1736 command line option "no387", which comes handy if your coprocessor 1737 is broken. Try "man bootparam" or see the documentation of your boot 1738 loader (lilo or loadlin) about how to pass options to the kernel at 1739 boot time.) This means that it is a good idea to say Y here if you 1740 intend to use this kernel on different machines. 1741 1742 More information about the internals of the Linux math coprocessor 1743 emulation can be found in <file:arch/x86/math-emu/README>. 1744 1745 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1746 kernel, it won't hurt. 1747 1748config MTRR 1749 def_bool y 1750 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1751 help 1752 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1753 the Memory Type Range Registers (MTRRs) may be used to control 1754 processor access to memory ranges. This is most useful if you have 1755 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1756 allows bus write transfers to be combined into a larger transfer 1757 before bursting over the PCI/AGP bus. This can increase performance 1758 of image write operations 2.5 times or more. Saying Y here creates a 1759 /proc/mtrr file which may be used to manipulate your processor's 1760 MTRRs. Typically the X server should use this. 1761 1762 This code has a reasonably generic interface so that similar 1763 control registers on other processors can be easily supported 1764 as well: 1765 1766 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1767 Registers (ARRs) which provide a similar functionality to MTRRs. For 1768 these, the ARRs are used to emulate the MTRRs. 1769 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1770 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1771 write-combining. All of these processors are supported by this code 1772 and it makes sense to say Y here if you have one of them. 1773 1774 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1775 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1776 can lead to all sorts of problems, so it's good to say Y here. 1777 1778 You can safely say Y even if your machine doesn't have MTRRs, you'll 1779 just add about 9 KB to your kernel. 1780 1781 See <file:Documentation/x86/mtrr.rst> for more information. 1782 1783config MTRR_SANITIZER 1784 def_bool y 1785 prompt "MTRR cleanup support" 1786 depends on MTRR 1787 help 1788 Convert MTRR layout from continuous to discrete, so X drivers can 1789 add writeback entries. 1790 1791 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1792 The largest mtrr entry size for a continuous block can be set with 1793 mtrr_chunk_size. 1794 1795 If unsure, say Y. 1796 1797config MTRR_SANITIZER_ENABLE_DEFAULT 1798 int "MTRR cleanup enable value (0-1)" 1799 range 0 1 1800 default "0" 1801 depends on MTRR_SANITIZER 1802 help 1803 Enable mtrr cleanup default value 1804 1805config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1806 int "MTRR cleanup spare reg num (0-7)" 1807 range 0 7 1808 default "1" 1809 depends on MTRR_SANITIZER 1810 help 1811 mtrr cleanup spare entries default, it can be changed via 1812 mtrr_spare_reg_nr=N on the kernel command line. 1813 1814config X86_PAT 1815 def_bool y 1816 prompt "x86 PAT support" if EXPERT 1817 depends on MTRR 1818 help 1819 Use PAT attributes to setup page level cache control. 1820 1821 PATs are the modern equivalents of MTRRs and are much more 1822 flexible than MTRRs. 1823 1824 Say N here if you see bootup problems (boot crash, boot hang, 1825 spontaneous reboots) or a non-working video driver. 1826 1827 If unsure, say Y. 1828 1829config ARCH_USES_PG_UNCACHED 1830 def_bool y 1831 depends on X86_PAT 1832 1833config ARCH_RANDOM 1834 def_bool y 1835 prompt "x86 architectural random number generator" if EXPERT 1836 help 1837 Enable the x86 architectural RDRAND instruction 1838 (Intel Bull Mountain technology) to generate random numbers. 1839 If supported, this is a high bandwidth, cryptographically 1840 secure hardware random number generator. 1841 1842config X86_SMAP 1843 def_bool y 1844 prompt "Supervisor Mode Access Prevention" if EXPERT 1845 help 1846 Supervisor Mode Access Prevention (SMAP) is a security 1847 feature in newer Intel processors. There is a small 1848 performance cost if this enabled and turned on; there is 1849 also a small increase in the kernel size if this is enabled. 1850 1851 If unsure, say Y. 1852 1853config X86_UMIP 1854 def_bool y 1855 prompt "User Mode Instruction Prevention" if EXPERT 1856 help 1857 User Mode Instruction Prevention (UMIP) is a security feature in 1858 some x86 processors. If enabled, a general protection fault is 1859 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1860 executed in user mode. These instructions unnecessarily expose 1861 information about the hardware state. 1862 1863 The vast majority of applications do not use these instructions. 1864 For the very few that do, software emulation is provided in 1865 specific cases in protected and virtual-8086 modes. Emulated 1866 results are dummy. 1867 1868config X86_INTEL_MEMORY_PROTECTION_KEYS 1869 prompt "Memory Protection Keys" 1870 def_bool y 1871 # Note: only available in 64-bit mode 1872 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1873 select ARCH_USES_HIGH_VMA_FLAGS 1874 select ARCH_HAS_PKEYS 1875 help 1876 Memory Protection Keys provides a mechanism for enforcing 1877 page-based protections, but without requiring modification of the 1878 page tables when an application changes protection domains. 1879 1880 For details, see Documentation/core-api/protection-keys.rst 1881 1882 If unsure, say y. 1883 1884choice 1885 prompt "TSX enable mode" 1886 depends on CPU_SUP_INTEL 1887 default X86_INTEL_TSX_MODE_OFF 1888 help 1889 Intel's TSX (Transactional Synchronization Extensions) feature 1890 allows to optimize locking protocols through lock elision which 1891 can lead to a noticeable performance boost. 1892 1893 On the other hand it has been shown that TSX can be exploited 1894 to form side channel attacks (e.g. TAA) and chances are there 1895 will be more of those attacks discovered in the future. 1896 1897 Therefore TSX is not enabled by default (aka tsx=off). An admin 1898 might override this decision by tsx=on the command line parameter. 1899 Even with TSX enabled, the kernel will attempt to enable the best 1900 possible TAA mitigation setting depending on the microcode available 1901 for the particular machine. 1902 1903 This option allows to set the default tsx mode between tsx=on, =off 1904 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1905 details. 1906 1907 Say off if not sure, auto if TSX is in use but it should be used on safe 1908 platforms or on if TSX is in use and the security aspect of tsx is not 1909 relevant. 1910 1911config X86_INTEL_TSX_MODE_OFF 1912 bool "off" 1913 help 1914 TSX is disabled if possible - equals to tsx=off command line parameter. 1915 1916config X86_INTEL_TSX_MODE_ON 1917 bool "on" 1918 help 1919 TSX is always enabled on TSX capable HW - equals the tsx=on command 1920 line parameter. 1921 1922config X86_INTEL_TSX_MODE_AUTO 1923 bool "auto" 1924 help 1925 TSX is enabled on TSX capable HW that is believed to be safe against 1926 side channel attacks- equals the tsx=auto command line parameter. 1927endchoice 1928 1929config EFI 1930 bool "EFI runtime service support" 1931 depends on ACPI 1932 select UCS2_STRING 1933 select EFI_RUNTIME_WRAPPERS 1934 help 1935 This enables the kernel to use EFI runtime services that are 1936 available (such as the EFI variable services). 1937 1938 This option is only useful on systems that have EFI firmware. 1939 In addition, you should use the latest ELILO loader available 1940 at <http://elilo.sourceforge.net> in order to take advantage 1941 of EFI runtime services. However, even with this option, the 1942 resultant kernel should continue to boot on existing non-EFI 1943 platforms. 1944 1945config EFI_STUB 1946 bool "EFI stub support" 1947 depends on EFI && !X86_USE_3DNOW 1948 depends on $(cc-option,-mabi=ms) || X86_32 1949 select RELOCATABLE 1950 help 1951 This kernel feature allows a bzImage to be loaded directly 1952 by EFI firmware without the use of a bootloader. 1953 1954 See Documentation/admin-guide/efi-stub.rst for more information. 1955 1956config EFI_MIXED 1957 bool "EFI mixed-mode support" 1958 depends on EFI_STUB && X86_64 1959 help 1960 Enabling this feature allows a 64-bit kernel to be booted 1961 on a 32-bit firmware, provided that your CPU supports 64-bit 1962 mode. 1963 1964 Note that it is not possible to boot a mixed-mode enabled 1965 kernel via the EFI boot stub - a bootloader that supports 1966 the EFI handover protocol must be used. 1967 1968 If unsure, say N. 1969 1970config SECCOMP 1971 def_bool y 1972 prompt "Enable seccomp to safely compute untrusted bytecode" 1973 help 1974 This kernel feature is useful for number crunching applications 1975 that may need to compute untrusted bytecode during their 1976 execution. By using pipes or other transports made available to 1977 the process as file descriptors supporting the read/write 1978 syscalls, it's possible to isolate those applications in 1979 their own address space using seccomp. Once seccomp is 1980 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 1981 and the task is only allowed to execute a few safe syscalls 1982 defined by each seccomp mode. 1983 1984 If unsure, say Y. Only embedded should say N here. 1985 1986source "kernel/Kconfig.hz" 1987 1988config KEXEC 1989 bool "kexec system call" 1990 select KEXEC_CORE 1991 help 1992 kexec is a system call that implements the ability to shutdown your 1993 current kernel, and to start another kernel. It is like a reboot 1994 but it is independent of the system firmware. And like a reboot 1995 you can start any kernel with it, not just Linux. 1996 1997 The name comes from the similarity to the exec system call. 1998 1999 It is an ongoing process to be certain the hardware in a machine 2000 is properly shutdown, so do not be surprised if this code does not 2001 initially work for you. As of this writing the exact hardware 2002 interface is strongly in flux, so no good recommendation can be 2003 made. 2004 2005config KEXEC_FILE 2006 bool "kexec file based system call" 2007 select KEXEC_CORE 2008 select BUILD_BIN2C 2009 depends on X86_64 2010 depends on CRYPTO=y 2011 depends on CRYPTO_SHA256=y 2012 help 2013 This is new version of kexec system call. This system call is 2014 file based and takes file descriptors as system call argument 2015 for kernel and initramfs as opposed to list of segments as 2016 accepted by previous system call. 2017 2018config ARCH_HAS_KEXEC_PURGATORY 2019 def_bool KEXEC_FILE 2020 2021config KEXEC_SIG 2022 bool "Verify kernel signature during kexec_file_load() syscall" 2023 depends on KEXEC_FILE 2024 help 2025 2026 This option makes the kexec_file_load() syscall check for a valid 2027 signature of the kernel image. The image can still be loaded without 2028 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2029 there's a signature that we can check, then it must be valid. 2030 2031 In addition to this option, you need to enable signature 2032 verification for the corresponding kernel image type being 2033 loaded in order for this to work. 2034 2035config KEXEC_SIG_FORCE 2036 bool "Require a valid signature in kexec_file_load() syscall" 2037 depends on KEXEC_SIG 2038 help 2039 This option makes kernel signature verification mandatory for 2040 the kexec_file_load() syscall. 2041 2042config KEXEC_BZIMAGE_VERIFY_SIG 2043 bool "Enable bzImage signature verification support" 2044 depends on KEXEC_SIG 2045 depends on SIGNED_PE_FILE_VERIFICATION 2046 select SYSTEM_TRUSTED_KEYRING 2047 help 2048 Enable bzImage signature verification support. 2049 2050config CRASH_DUMP 2051 bool "kernel crash dumps" 2052 depends on X86_64 || (X86_32 && HIGHMEM) 2053 help 2054 Generate crash dump after being started by kexec. 2055 This should be normally only set in special crash dump kernels 2056 which are loaded in the main kernel with kexec-tools into 2057 a specially reserved region and then later executed after 2058 a crash by kdump/kexec. The crash dump kernel must be compiled 2059 to a memory address not used by the main kernel or BIOS using 2060 PHYSICAL_START, or it must be built as a relocatable image 2061 (CONFIG_RELOCATABLE=y). 2062 For more details see Documentation/admin-guide/kdump/kdump.rst 2063 2064config KEXEC_JUMP 2065 bool "kexec jump" 2066 depends on KEXEC && HIBERNATION 2067 help 2068 Jump between original kernel and kexeced kernel and invoke 2069 code in physical address mode via KEXEC 2070 2071config PHYSICAL_START 2072 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2073 default "0x1000000" 2074 help 2075 This gives the physical address where the kernel is loaded. 2076 2077 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2078 bzImage will decompress itself to above physical address and 2079 run from there. Otherwise, bzImage will run from the address where 2080 it has been loaded by the boot loader and will ignore above physical 2081 address. 2082 2083 In normal kdump cases one does not have to set/change this option 2084 as now bzImage can be compiled as a completely relocatable image 2085 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2086 address. This option is mainly useful for the folks who don't want 2087 to use a bzImage for capturing the crash dump and want to use a 2088 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2089 to be specifically compiled to run from a specific memory area 2090 (normally a reserved region) and this option comes handy. 2091 2092 So if you are using bzImage for capturing the crash dump, 2093 leave the value here unchanged to 0x1000000 and set 2094 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2095 for capturing the crash dump change this value to start of 2096 the reserved region. In other words, it can be set based on 2097 the "X" value as specified in the "crashkernel=YM@XM" 2098 command line boot parameter passed to the panic-ed 2099 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2100 for more details about crash dumps. 2101 2102 Usage of bzImage for capturing the crash dump is recommended as 2103 one does not have to build two kernels. Same kernel can be used 2104 as production kernel and capture kernel. Above option should have 2105 gone away after relocatable bzImage support is introduced. But it 2106 is present because there are users out there who continue to use 2107 vmlinux for dump capture. This option should go away down the 2108 line. 2109 2110 Don't change this unless you know what you are doing. 2111 2112config RELOCATABLE 2113 bool "Build a relocatable kernel" 2114 default y 2115 help 2116 This builds a kernel image that retains relocation information 2117 so it can be loaded someplace besides the default 1MB. 2118 The relocations tend to make the kernel binary about 10% larger, 2119 but are discarded at runtime. 2120 2121 One use is for the kexec on panic case where the recovery kernel 2122 must live at a different physical address than the primary 2123 kernel. 2124 2125 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2126 it has been loaded at and the compile time physical address 2127 (CONFIG_PHYSICAL_START) is used as the minimum location. 2128 2129config RANDOMIZE_BASE 2130 bool "Randomize the address of the kernel image (KASLR)" 2131 depends on RELOCATABLE 2132 default y 2133 help 2134 In support of Kernel Address Space Layout Randomization (KASLR), 2135 this randomizes the physical address at which the kernel image 2136 is decompressed and the virtual address where the kernel 2137 image is mapped, as a security feature that deters exploit 2138 attempts relying on knowledge of the location of kernel 2139 code internals. 2140 2141 On 64-bit, the kernel physical and virtual addresses are 2142 randomized separately. The physical address will be anywhere 2143 between 16MB and the top of physical memory (up to 64TB). The 2144 virtual address will be randomized from 16MB up to 1GB (9 bits 2145 of entropy). Note that this also reduces the memory space 2146 available to kernel modules from 1.5GB to 1GB. 2147 2148 On 32-bit, the kernel physical and virtual addresses are 2149 randomized together. They will be randomized from 16MB up to 2150 512MB (8 bits of entropy). 2151 2152 Entropy is generated using the RDRAND instruction if it is 2153 supported. If RDTSC is supported, its value is mixed into 2154 the entropy pool as well. If neither RDRAND nor RDTSC are 2155 supported, then entropy is read from the i8254 timer. The 2156 usable entropy is limited by the kernel being built using 2157 2GB addressing, and that PHYSICAL_ALIGN must be at a 2158 minimum of 2MB. As a result, only 10 bits of entropy are 2159 theoretically possible, but the implementations are further 2160 limited due to memory layouts. 2161 2162 If unsure, say Y. 2163 2164# Relocation on x86 needs some additional build support 2165config X86_NEED_RELOCS 2166 def_bool y 2167 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2168 2169config PHYSICAL_ALIGN 2170 hex "Alignment value to which kernel should be aligned" 2171 default "0x200000" 2172 range 0x2000 0x1000000 if X86_32 2173 range 0x200000 0x1000000 if X86_64 2174 help 2175 This value puts the alignment restrictions on physical address 2176 where kernel is loaded and run from. Kernel is compiled for an 2177 address which meets above alignment restriction. 2178 2179 If bootloader loads the kernel at a non-aligned address and 2180 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2181 address aligned to above value and run from there. 2182 2183 If bootloader loads the kernel at a non-aligned address and 2184 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2185 load address and decompress itself to the address it has been 2186 compiled for and run from there. The address for which kernel is 2187 compiled already meets above alignment restrictions. Hence the 2188 end result is that kernel runs from a physical address meeting 2189 above alignment restrictions. 2190 2191 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2192 this value must be a multiple of 0x200000. 2193 2194 Don't change this unless you know what you are doing. 2195 2196config DYNAMIC_MEMORY_LAYOUT 2197 bool 2198 help 2199 This option makes base addresses of vmalloc and vmemmap as well as 2200 __PAGE_OFFSET movable during boot. 2201 2202config RANDOMIZE_MEMORY 2203 bool "Randomize the kernel memory sections" 2204 depends on X86_64 2205 depends on RANDOMIZE_BASE 2206 select DYNAMIC_MEMORY_LAYOUT 2207 default RANDOMIZE_BASE 2208 help 2209 Randomizes the base virtual address of kernel memory sections 2210 (physical memory mapping, vmalloc & vmemmap). This security feature 2211 makes exploits relying on predictable memory locations less reliable. 2212 2213 The order of allocations remains unchanged. Entropy is generated in 2214 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2215 configuration have in average 30,000 different possible virtual 2216 addresses for each memory section. 2217 2218 If unsure, say Y. 2219 2220config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2221 hex "Physical memory mapping padding" if EXPERT 2222 depends on RANDOMIZE_MEMORY 2223 default "0xa" if MEMORY_HOTPLUG 2224 default "0x0" 2225 range 0x1 0x40 if MEMORY_HOTPLUG 2226 range 0x0 0x40 2227 help 2228 Define the padding in terabytes added to the existing physical 2229 memory size during kernel memory randomization. It is useful 2230 for memory hotplug support but reduces the entropy available for 2231 address randomization. 2232 2233 If unsure, leave at the default value. 2234 2235config HOTPLUG_CPU 2236 def_bool y 2237 depends on SMP 2238 2239config BOOTPARAM_HOTPLUG_CPU0 2240 bool "Set default setting of cpu0_hotpluggable" 2241 depends on HOTPLUG_CPU 2242 help 2243 Set whether default state of cpu0_hotpluggable is on or off. 2244 2245 Say Y here to enable CPU0 hotplug by default. If this switch 2246 is turned on, there is no need to give cpu0_hotplug kernel 2247 parameter and the CPU0 hotplug feature is enabled by default. 2248 2249 Please note: there are two known CPU0 dependencies if you want 2250 to enable the CPU0 hotplug feature either by this switch or by 2251 cpu0_hotplug kernel parameter. 2252 2253 First, resume from hibernate or suspend always starts from CPU0. 2254 So hibernate and suspend are prevented if CPU0 is offline. 2255 2256 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2257 offline if any interrupt can not migrate out of CPU0. There may 2258 be other CPU0 dependencies. 2259 2260 Please make sure the dependencies are under your control before 2261 you enable this feature. 2262 2263 Say N if you don't want to enable CPU0 hotplug feature by default. 2264 You still can enable the CPU0 hotplug feature at boot by kernel 2265 parameter cpu0_hotplug. 2266 2267config DEBUG_HOTPLUG_CPU0 2268 def_bool n 2269 prompt "Debug CPU0 hotplug" 2270 depends on HOTPLUG_CPU 2271 help 2272 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2273 soon as possible and boots up userspace with CPU0 offlined. User 2274 can online CPU0 back after boot time. 2275 2276 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2277 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2278 compilation or giving cpu0_hotplug kernel parameter at boot. 2279 2280 If unsure, say N. 2281 2282config COMPAT_VDSO 2283 def_bool n 2284 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2285 depends on COMPAT_32 2286 help 2287 Certain buggy versions of glibc will crash if they are 2288 presented with a 32-bit vDSO that is not mapped at the address 2289 indicated in its segment table. 2290 2291 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2292 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2293 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2294 the only released version with the bug, but OpenSUSE 9 2295 contains a buggy "glibc 2.3.2". 2296 2297 The symptom of the bug is that everything crashes on startup, saying: 2298 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2299 2300 Saying Y here changes the default value of the vdso32 boot 2301 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2302 This works around the glibc bug but hurts performance. 2303 2304 If unsure, say N: if you are compiling your own kernel, you 2305 are unlikely to be using a buggy version of glibc. 2306 2307choice 2308 prompt "vsyscall table for legacy applications" 2309 depends on X86_64 2310 default LEGACY_VSYSCALL_XONLY 2311 help 2312 Legacy user code that does not know how to find the vDSO expects 2313 to be able to issue three syscalls by calling fixed addresses in 2314 kernel space. Since this location is not randomized with ASLR, 2315 it can be used to assist security vulnerability exploitation. 2316 2317 This setting can be changed at boot time via the kernel command 2318 line parameter vsyscall=[emulate|xonly|none]. 2319 2320 On a system with recent enough glibc (2.14 or newer) and no 2321 static binaries, you can say None without a performance penalty 2322 to improve security. 2323 2324 If unsure, select "Emulate execution only". 2325 2326 config LEGACY_VSYSCALL_EMULATE 2327 bool "Full emulation" 2328 help 2329 The kernel traps and emulates calls into the fixed vsyscall 2330 address mapping. This makes the mapping non-executable, but 2331 it still contains readable known contents, which could be 2332 used in certain rare security vulnerability exploits. This 2333 configuration is recommended when using legacy userspace 2334 that still uses vsyscalls along with legacy binary 2335 instrumentation tools that require code to be readable. 2336 2337 An example of this type of legacy userspace is running 2338 Pin on an old binary that still uses vsyscalls. 2339 2340 config LEGACY_VSYSCALL_XONLY 2341 bool "Emulate execution only" 2342 help 2343 The kernel traps and emulates calls into the fixed vsyscall 2344 address mapping and does not allow reads. This 2345 configuration is recommended when userspace might use the 2346 legacy vsyscall area but support for legacy binary 2347 instrumentation of legacy code is not needed. It mitigates 2348 certain uses of the vsyscall area as an ASLR-bypassing 2349 buffer. 2350 2351 config LEGACY_VSYSCALL_NONE 2352 bool "None" 2353 help 2354 There will be no vsyscall mapping at all. This will 2355 eliminate any risk of ASLR bypass due to the vsyscall 2356 fixed address mapping. Attempts to use the vsyscalls 2357 will be reported to dmesg, so that either old or 2358 malicious userspace programs can be identified. 2359 2360endchoice 2361 2362config CMDLINE_BOOL 2363 bool "Built-in kernel command line" 2364 help 2365 Allow for specifying boot arguments to the kernel at 2366 build time. On some systems (e.g. embedded ones), it is 2367 necessary or convenient to provide some or all of the 2368 kernel boot arguments with the kernel itself (that is, 2369 to not rely on the boot loader to provide them.) 2370 2371 To compile command line arguments into the kernel, 2372 set this option to 'Y', then fill in the 2373 boot arguments in CONFIG_CMDLINE. 2374 2375 Systems with fully functional boot loaders (i.e. non-embedded) 2376 should leave this option set to 'N'. 2377 2378config CMDLINE 2379 string "Built-in kernel command string" 2380 depends on CMDLINE_BOOL 2381 default "" 2382 help 2383 Enter arguments here that should be compiled into the kernel 2384 image and used at boot time. If the boot loader provides a 2385 command line at boot time, it is appended to this string to 2386 form the full kernel command line, when the system boots. 2387 2388 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2389 change this behavior. 2390 2391 In most cases, the command line (whether built-in or provided 2392 by the boot loader) should specify the device for the root 2393 file system. 2394 2395config CMDLINE_OVERRIDE 2396 bool "Built-in command line overrides boot loader arguments" 2397 depends on CMDLINE_BOOL && CMDLINE != "" 2398 help 2399 Set this option to 'Y' to have the kernel ignore the boot loader 2400 command line, and use ONLY the built-in command line. 2401 2402 This is used to work around broken boot loaders. This should 2403 be set to 'N' under normal conditions. 2404 2405config MODIFY_LDT_SYSCALL 2406 bool "Enable the LDT (local descriptor table)" if EXPERT 2407 default y 2408 help 2409 Linux can allow user programs to install a per-process x86 2410 Local Descriptor Table (LDT) using the modify_ldt(2) system 2411 call. This is required to run 16-bit or segmented code such as 2412 DOSEMU or some Wine programs. It is also used by some very old 2413 threading libraries. 2414 2415 Enabling this feature adds a small amount of overhead to 2416 context switches and increases the low-level kernel attack 2417 surface. Disabling it removes the modify_ldt(2) system call. 2418 2419 Saying 'N' here may make sense for embedded or server kernels. 2420 2421source "kernel/livepatch/Kconfig" 2422 2423endmenu 2424 2425config ARCH_HAS_ADD_PAGES 2426 def_bool y 2427 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2428 2429config ARCH_ENABLE_MEMORY_HOTPLUG 2430 def_bool y 2431 depends on X86_64 || (X86_32 && HIGHMEM) 2432 2433config ARCH_ENABLE_MEMORY_HOTREMOVE 2434 def_bool y 2435 depends on MEMORY_HOTPLUG 2436 2437config USE_PERCPU_NUMA_NODE_ID 2438 def_bool y 2439 depends on NUMA 2440 2441config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2442 def_bool y 2443 depends on X86_64 || X86_PAE 2444 2445config ARCH_ENABLE_HUGEPAGE_MIGRATION 2446 def_bool y 2447 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2448 2449config ARCH_ENABLE_THP_MIGRATION 2450 def_bool y 2451 depends on X86_64 && TRANSPARENT_HUGEPAGE 2452 2453menu "Power management and ACPI options" 2454 2455config ARCH_HIBERNATION_HEADER 2456 def_bool y 2457 depends on HIBERNATION 2458 2459source "kernel/power/Kconfig" 2460 2461source "drivers/acpi/Kconfig" 2462 2463source "drivers/sfi/Kconfig" 2464 2465config X86_APM_BOOT 2466 def_bool y 2467 depends on APM 2468 2469menuconfig APM 2470 tristate "APM (Advanced Power Management) BIOS support" 2471 depends on X86_32 && PM_SLEEP 2472 help 2473 APM is a BIOS specification for saving power using several different 2474 techniques. This is mostly useful for battery powered laptops with 2475 APM compliant BIOSes. If you say Y here, the system time will be 2476 reset after a RESUME operation, the /proc/apm device will provide 2477 battery status information, and user-space programs will receive 2478 notification of APM "events" (e.g. battery status change). 2479 2480 If you select "Y" here, you can disable actual use of the APM 2481 BIOS by passing the "apm=off" option to the kernel at boot time. 2482 2483 Note that the APM support is almost completely disabled for 2484 machines with more than one CPU. 2485 2486 In order to use APM, you will need supporting software. For location 2487 and more information, read <file:Documentation/power/apm-acpi.rst> 2488 and the Battery Powered Linux mini-HOWTO, available from 2489 <http://www.tldp.org/docs.html#howto>. 2490 2491 This driver does not spin down disk drives (see the hdparm(8) 2492 manpage ("man 8 hdparm") for that), and it doesn't turn off 2493 VESA-compliant "green" monitors. 2494 2495 This driver does not support the TI 4000M TravelMate and the ACER 2496 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2497 desktop machines also don't have compliant BIOSes, and this driver 2498 may cause those machines to panic during the boot phase. 2499 2500 Generally, if you don't have a battery in your machine, there isn't 2501 much point in using this driver and you should say N. If you get 2502 random kernel OOPSes or reboots that don't seem to be related to 2503 anything, try disabling/enabling this option (or disabling/enabling 2504 APM in your BIOS). 2505 2506 Some other things you should try when experiencing seemingly random, 2507 "weird" problems: 2508 2509 1) make sure that you have enough swap space and that it is 2510 enabled. 2511 2) pass the "no-hlt" option to the kernel 2512 3) switch on floating point emulation in the kernel and pass 2513 the "no387" option to the kernel 2514 4) pass the "floppy=nodma" option to the kernel 2515 5) pass the "mem=4M" option to the kernel (thereby disabling 2516 all but the first 4 MB of RAM) 2517 6) make sure that the CPU is not over clocked. 2518 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2519 8) disable the cache from your BIOS settings 2520 9) install a fan for the video card or exchange video RAM 2521 10) install a better fan for the CPU 2522 11) exchange RAM chips 2523 12) exchange the motherboard. 2524 2525 To compile this driver as a module, choose M here: the 2526 module will be called apm. 2527 2528if APM 2529 2530config APM_IGNORE_USER_SUSPEND 2531 bool "Ignore USER SUSPEND" 2532 help 2533 This option will ignore USER SUSPEND requests. On machines with a 2534 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2535 series notebooks, it is necessary to say Y because of a BIOS bug. 2536 2537config APM_DO_ENABLE 2538 bool "Enable PM at boot time" 2539 help 2540 Enable APM features at boot time. From page 36 of the APM BIOS 2541 specification: "When disabled, the APM BIOS does not automatically 2542 power manage devices, enter the Standby State, enter the Suspend 2543 State, or take power saving steps in response to CPU Idle calls." 2544 This driver will make CPU Idle calls when Linux is idle (unless this 2545 feature is turned off -- see "Do CPU IDLE calls", below). This 2546 should always save battery power, but more complicated APM features 2547 will be dependent on your BIOS implementation. You may need to turn 2548 this option off if your computer hangs at boot time when using APM 2549 support, or if it beeps continuously instead of suspending. Turn 2550 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2551 T400CDT. This is off by default since most machines do fine without 2552 this feature. 2553 2554config APM_CPU_IDLE 2555 depends on CPU_IDLE 2556 bool "Make CPU Idle calls when idle" 2557 help 2558 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2559 On some machines, this can activate improved power savings, such as 2560 a slowed CPU clock rate, when the machine is idle. These idle calls 2561 are made after the idle loop has run for some length of time (e.g., 2562 333 mS). On some machines, this will cause a hang at boot time or 2563 whenever the CPU becomes idle. (On machines with more than one CPU, 2564 this option does nothing.) 2565 2566config APM_DISPLAY_BLANK 2567 bool "Enable console blanking using APM" 2568 help 2569 Enable console blanking using the APM. Some laptops can use this to 2570 turn off the LCD backlight when the screen blanker of the Linux 2571 virtual console blanks the screen. Note that this is only used by 2572 the virtual console screen blanker, and won't turn off the backlight 2573 when using the X Window system. This also doesn't have anything to 2574 do with your VESA-compliant power-saving monitor. Further, this 2575 option doesn't work for all laptops -- it might not turn off your 2576 backlight at all, or it might print a lot of errors to the console, 2577 especially if you are using gpm. 2578 2579config APM_ALLOW_INTS 2580 bool "Allow interrupts during APM BIOS calls" 2581 help 2582 Normally we disable external interrupts while we are making calls to 2583 the APM BIOS as a measure to lessen the effects of a badly behaving 2584 BIOS implementation. The BIOS should reenable interrupts if it 2585 needs to. Unfortunately, some BIOSes do not -- especially those in 2586 many of the newer IBM Thinkpads. If you experience hangs when you 2587 suspend, try setting this to Y. Otherwise, say N. 2588 2589endif # APM 2590 2591source "drivers/cpufreq/Kconfig" 2592 2593source "drivers/cpuidle/Kconfig" 2594 2595source "drivers/idle/Kconfig" 2596 2597endmenu 2598 2599 2600menu "Bus options (PCI etc.)" 2601 2602choice 2603 prompt "PCI access mode" 2604 depends on X86_32 && PCI 2605 default PCI_GOANY 2606 help 2607 On PCI systems, the BIOS can be used to detect the PCI devices and 2608 determine their configuration. However, some old PCI motherboards 2609 have BIOS bugs and may crash if this is done. Also, some embedded 2610 PCI-based systems don't have any BIOS at all. Linux can also try to 2611 detect the PCI hardware directly without using the BIOS. 2612 2613 With this option, you can specify how Linux should detect the 2614 PCI devices. If you choose "BIOS", the BIOS will be used, 2615 if you choose "Direct", the BIOS won't be used, and if you 2616 choose "MMConfig", then PCI Express MMCONFIG will be used. 2617 If you choose "Any", the kernel will try MMCONFIG, then the 2618 direct access method and falls back to the BIOS if that doesn't 2619 work. If unsure, go with the default, which is "Any". 2620 2621config PCI_GOBIOS 2622 bool "BIOS" 2623 2624config PCI_GOMMCONFIG 2625 bool "MMConfig" 2626 2627config PCI_GODIRECT 2628 bool "Direct" 2629 2630config PCI_GOOLPC 2631 bool "OLPC XO-1" 2632 depends on OLPC 2633 2634config PCI_GOANY 2635 bool "Any" 2636 2637endchoice 2638 2639config PCI_BIOS 2640 def_bool y 2641 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2642 2643# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2644config PCI_DIRECT 2645 def_bool y 2646 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2647 2648config PCI_MMCONFIG 2649 bool "Support mmconfig PCI config space access" if X86_64 2650 default y 2651 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2652 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2653 2654config PCI_OLPC 2655 def_bool y 2656 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2657 2658config PCI_XEN 2659 def_bool y 2660 depends on PCI && XEN 2661 select SWIOTLB_XEN 2662 2663config MMCONF_FAM10H 2664 def_bool y 2665 depends on X86_64 && PCI_MMCONFIG && ACPI 2666 2667config PCI_CNB20LE_QUIRK 2668 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2669 depends on PCI 2670 help 2671 Read the PCI windows out of the CNB20LE host bridge. This allows 2672 PCI hotplug to work on systems with the CNB20LE chipset which do 2673 not have ACPI. 2674 2675 There's no public spec for this chipset, and this functionality 2676 is known to be incomplete. 2677 2678 You should say N unless you know you need this. 2679 2680config ISA_BUS 2681 bool "ISA bus support on modern systems" if EXPERT 2682 help 2683 Expose ISA bus device drivers and options available for selection and 2684 configuration. Enable this option if your target machine has an ISA 2685 bus. ISA is an older system, displaced by PCI and newer bus 2686 architectures -- if your target machine is modern, it probably does 2687 not have an ISA bus. 2688 2689 If unsure, say N. 2690 2691# x86_64 have no ISA slots, but can have ISA-style DMA. 2692config ISA_DMA_API 2693 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2694 default y 2695 help 2696 Enables ISA-style DMA support for devices requiring such controllers. 2697 If unsure, say Y. 2698 2699if X86_32 2700 2701config ISA 2702 bool "ISA support" 2703 help 2704 Find out whether you have ISA slots on your motherboard. ISA is the 2705 name of a bus system, i.e. the way the CPU talks to the other stuff 2706 inside your box. Other bus systems are PCI, EISA, MicroChannel 2707 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2708 newer boards don't support it. If you have ISA, say Y, otherwise N. 2709 2710config SCx200 2711 tristate "NatSemi SCx200 support" 2712 help 2713 This provides basic support for National Semiconductor's 2714 (now AMD's) Geode processors. The driver probes for the 2715 PCI-IDs of several on-chip devices, so its a good dependency 2716 for other scx200_* drivers. 2717 2718 If compiled as a module, the driver is named scx200. 2719 2720config SCx200HR_TIMER 2721 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2722 depends on SCx200 2723 default y 2724 help 2725 This driver provides a clocksource built upon the on-chip 2726 27MHz high-resolution timer. Its also a workaround for 2727 NSC Geode SC-1100's buggy TSC, which loses time when the 2728 processor goes idle (as is done by the scheduler). The 2729 other workaround is idle=poll boot option. 2730 2731config OLPC 2732 bool "One Laptop Per Child support" 2733 depends on !X86_PAE 2734 select GPIOLIB 2735 select OF 2736 select OF_PROMTREE 2737 select IRQ_DOMAIN 2738 select OLPC_EC 2739 help 2740 Add support for detecting the unique features of the OLPC 2741 XO hardware. 2742 2743config OLPC_XO1_PM 2744 bool "OLPC XO-1 Power Management" 2745 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2746 help 2747 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2748 2749config OLPC_XO1_RTC 2750 bool "OLPC XO-1 Real Time Clock" 2751 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2752 help 2753 Add support for the XO-1 real time clock, which can be used as a 2754 programmable wakeup source. 2755 2756config OLPC_XO1_SCI 2757 bool "OLPC XO-1 SCI extras" 2758 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2759 depends on INPUT=y 2760 select POWER_SUPPLY 2761 help 2762 Add support for SCI-based features of the OLPC XO-1 laptop: 2763 - EC-driven system wakeups 2764 - Power button 2765 - Ebook switch 2766 - Lid switch 2767 - AC adapter status updates 2768 - Battery status updates 2769 2770config OLPC_XO15_SCI 2771 bool "OLPC XO-1.5 SCI extras" 2772 depends on OLPC && ACPI 2773 select POWER_SUPPLY 2774 help 2775 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2776 - EC-driven system wakeups 2777 - AC adapter status updates 2778 - Battery status updates 2779 2780config ALIX 2781 bool "PCEngines ALIX System Support (LED setup)" 2782 select GPIOLIB 2783 help 2784 This option enables system support for the PCEngines ALIX. 2785 At present this just sets up LEDs for GPIO control on 2786 ALIX2/3/6 boards. However, other system specific setup should 2787 get added here. 2788 2789 Note: You must still enable the drivers for GPIO and LED support 2790 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2791 2792 Note: You have to set alix.force=1 for boards with Award BIOS. 2793 2794config NET5501 2795 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2796 select GPIOLIB 2797 help 2798 This option enables system support for the Soekris Engineering net5501. 2799 2800config GEOS 2801 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2802 select GPIOLIB 2803 depends on DMI 2804 help 2805 This option enables system support for the Traverse Technologies GEOS. 2806 2807config TS5500 2808 bool "Technologic Systems TS-5500 platform support" 2809 depends on MELAN 2810 select CHECK_SIGNATURE 2811 select NEW_LEDS 2812 select LEDS_CLASS 2813 help 2814 This option enables system support for the Technologic Systems TS-5500. 2815 2816endif # X86_32 2817 2818config AMD_NB 2819 def_bool y 2820 depends on CPU_SUP_AMD && PCI 2821 2822config X86_SYSFB 2823 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2824 help 2825 Firmwares often provide initial graphics framebuffers so the BIOS, 2826 bootloader or kernel can show basic video-output during boot for 2827 user-guidance and debugging. Historically, x86 used the VESA BIOS 2828 Extensions and EFI-framebuffers for this, which are mostly limited 2829 to x86. 2830 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2831 framebuffers so the new generic system-framebuffer drivers can be 2832 used on x86. If the framebuffer is not compatible with the generic 2833 modes, it is advertised as fallback platform framebuffer so legacy 2834 drivers like efifb, vesafb and uvesafb can pick it up. 2835 If this option is not selected, all system framebuffers are always 2836 marked as fallback platform framebuffers as usual. 2837 2838 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2839 not be able to pick up generic system framebuffers if this option 2840 is selected. You are highly encouraged to enable simplefb as 2841 replacement if you select this option. simplefb can correctly deal 2842 with generic system framebuffers. But you should still keep vesafb 2843 and others enabled as fallback if a system framebuffer is 2844 incompatible with simplefb. 2845 2846 If unsure, say Y. 2847 2848endmenu 2849 2850 2851menu "Binary Emulations" 2852 2853config IA32_EMULATION 2854 bool "IA32 Emulation" 2855 depends on X86_64 2856 select ARCH_WANT_OLD_COMPAT_IPC 2857 select BINFMT_ELF 2858 select COMPAT_BINFMT_ELF 2859 select COMPAT_OLD_SIGACTION 2860 help 2861 Include code to run legacy 32-bit programs under a 2862 64-bit kernel. You should likely turn this on, unless you're 2863 100% sure that you don't have any 32-bit programs left. 2864 2865config IA32_AOUT 2866 tristate "IA32 a.out support" 2867 depends on IA32_EMULATION 2868 depends on BROKEN 2869 help 2870 Support old a.out binaries in the 32bit emulation. 2871 2872config X86_X32 2873 bool "x32 ABI for 64-bit mode" 2874 depends on X86_64 2875 help 2876 Include code to run binaries for the x32 native 32-bit ABI 2877 for 64-bit processors. An x32 process gets access to the 2878 full 64-bit register file and wide data path while leaving 2879 pointers at 32 bits for smaller memory footprint. 2880 2881 You will need a recent binutils (2.22 or later) with 2882 elf32_x86_64 support enabled to compile a kernel with this 2883 option set. 2884 2885config COMPAT_32 2886 def_bool y 2887 depends on IA32_EMULATION || X86_32 2888 select HAVE_UID16 2889 select OLD_SIGSUSPEND3 2890 2891config COMPAT 2892 def_bool y 2893 depends on IA32_EMULATION || X86_X32 2894 2895if COMPAT 2896config COMPAT_FOR_U64_ALIGNMENT 2897 def_bool y 2898 2899config SYSVIPC_COMPAT 2900 def_bool y 2901 depends on SYSVIPC 2902endif 2903 2904endmenu 2905 2906 2907config HAVE_ATOMIC_IOMAP 2908 def_bool y 2909 depends on X86_32 2910 2911source "drivers/firmware/Kconfig" 2912 2913source "arch/x86/kvm/Kconfig" 2914 2915source "arch/x86/Kconfig.assembler" 2916