1# SPDX-License-Identifier: GPL-2.0 2# Select 32 or 64 bit 3config 64BIT 4 bool "64-bit kernel" if "$(ARCH)" = "x86" 5 default "$(ARCH)" != "i386" 6 help 7 Say yes to build a 64-bit kernel - formerly known as x86_64 8 Say no to build a 32-bit kernel - formerly known as i386 9 10config X86_32 11 def_bool y 12 depends on !64BIT 13 # Options that are inherently 32-bit kernel only: 14 select ARCH_WANT_IPC_PARSE_VERSION 15 select CLKSRC_I8253 16 select CLONE_BACKWARDS 17 select HAVE_DEBUG_STACKOVERFLOW 18 select MODULES_USE_ELF_REL 19 select OLD_SIGACTION 20 select GENERIC_VDSO_32 21 22config X86_64 23 def_bool y 24 depends on 64BIT 25 # Options that are inherently 64-bit kernel only: 26 select ARCH_HAS_GIGANTIC_PAGE 27 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 28 select ARCH_USE_CMPXCHG_LOCKREF 29 select HAVE_ARCH_SOFT_DIRTY 30 select MODULES_USE_ELF_RELA 31 select NEED_DMA_MAP_STATE 32 select SWIOTLB 33 34config FORCE_DYNAMIC_FTRACE 35 def_bool y 36 depends on X86_32 37 depends on FUNCTION_TRACER 38 select DYNAMIC_FTRACE 39 help 40 We keep the static function tracing (!DYNAMIC_FTRACE) around 41 in order to test the non static function tracing in the 42 generic code, as other architectures still use it. But we 43 only need to keep it around for x86_64. No need to keep it 44 for x86_32. For x86_32, force DYNAMIC_FTRACE. 45# 46# Arch settings 47# 48# ( Note that options that are marked 'if X86_64' could in principle be 49# ported to 32-bit as well. ) 50# 51config X86 52 def_bool y 53 # 54 # Note: keep this list sorted alphabetically 55 # 56 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 57 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 58 select ARCH_32BIT_OFF_T if X86_32 59 select ARCH_CLOCKSOURCE_INIT 60 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 61 select ARCH_HAS_DEBUG_VIRTUAL 62 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 63 select ARCH_HAS_DEVMEM_IS_ALLOWED 64 select ARCH_HAS_EARLY_DEBUG if KGDB 65 select ARCH_HAS_ELF_RANDOMIZE 66 select ARCH_HAS_FAST_MULTIPLIER 67 select ARCH_HAS_FILTER_PGPROT 68 select ARCH_HAS_FORTIFY_SOURCE 69 select ARCH_HAS_GCOV_PROFILE_ALL 70 select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION 71 select ARCH_HAS_MEM_ENCRYPT 72 select ARCH_HAS_MEMBARRIER_SYNC_CORE 73 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 74 select ARCH_HAS_PMEM_API if X86_64 75 select ARCH_HAS_PTE_DEVMAP if X86_64 76 select ARCH_HAS_PTE_SPECIAL 77 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 78 select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE 79 select ARCH_HAS_SET_MEMORY 80 select ARCH_HAS_SET_DIRECT_MAP 81 select ARCH_HAS_STRICT_KERNEL_RWX 82 select ARCH_HAS_STRICT_MODULE_RWX 83 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 84 select ARCH_HAS_SYSCALL_WRAPPER 85 select ARCH_HAS_UBSAN_SANITIZE_ALL 86 select ARCH_HAS_DEBUG_WX 87 select ARCH_HAVE_NMI_SAFE_CMPXCHG 88 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 89 select ARCH_MIGHT_HAVE_PC_PARPORT 90 select ARCH_MIGHT_HAVE_PC_SERIO 91 select ARCH_STACKWALK 92 select ARCH_SUPPORTS_ACPI 93 select ARCH_SUPPORTS_ATOMIC_RMW 94 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 95 select ARCH_USE_BUILTIN_BSWAP 96 select ARCH_USE_QUEUED_RWLOCKS 97 select ARCH_USE_QUEUED_SPINLOCKS 98 select ARCH_USE_SYM_ANNOTATIONS 99 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 100 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 101 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 102 select ARCH_WANT_HUGE_PMD_SHARE 103 select ARCH_WANTS_THP_SWAP if X86_64 104 select BUILDTIME_TABLE_SORT 105 select CLKEVT_I8253 106 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 107 select CLOCKSOURCE_WATCHDOG 108 select DCACHE_WORD_ACCESS 109 select EDAC_ATOMIC_SCRUB 110 select EDAC_SUPPORT 111 select GENERIC_CLOCKEVENTS 112 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 113 select GENERIC_CLOCKEVENTS_MIN_ADJUST 114 select GENERIC_CMOS_UPDATE 115 select GENERIC_CPU_AUTOPROBE 116 select GENERIC_CPU_VULNERABILITIES 117 select GENERIC_EARLY_IOREMAP 118 select GENERIC_ENTRY 119 select GENERIC_FIND_FIRST_BIT 120 select GENERIC_IOMAP 121 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 122 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 123 select GENERIC_IRQ_MIGRATION if SMP 124 select GENERIC_IRQ_PROBE 125 select GENERIC_IRQ_RESERVATION_MODE 126 select GENERIC_IRQ_SHOW 127 select GENERIC_PENDING_IRQ if SMP 128 select GENERIC_PTDUMP 129 select GENERIC_SMP_IDLE_THREAD 130 select GENERIC_STRNCPY_FROM_USER 131 select GENERIC_STRNLEN_USER 132 select GENERIC_TIME_VSYSCALL 133 select GENERIC_GETTIMEOFDAY 134 select GENERIC_VDSO_TIME_NS 135 select GUP_GET_PTE_LOW_HIGH if X86_PAE 136 select HARDIRQS_SW_RESEND 137 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 138 select HAVE_ACPI_APEI if ACPI 139 select HAVE_ACPI_APEI_NMI if ACPI 140 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 141 select HAVE_ARCH_AUDITSYSCALL 142 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 143 select HAVE_ARCH_JUMP_LABEL 144 select HAVE_ARCH_JUMP_LABEL_RELATIVE 145 select HAVE_ARCH_KASAN if X86_64 146 select HAVE_ARCH_KASAN_VMALLOC if X86_64 147 select HAVE_ARCH_KGDB 148 select HAVE_ARCH_MMAP_RND_BITS if MMU 149 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 150 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 151 select HAVE_ARCH_PREL32_RELOCATIONS 152 select HAVE_ARCH_SECCOMP_FILTER 153 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 154 select HAVE_ARCH_STACKLEAK 155 select HAVE_ARCH_TRACEHOOK 156 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 157 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 158 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 159 select HAVE_ARCH_VMAP_STACK if X86_64 160 select HAVE_ARCH_WITHIN_STACK_FRAMES 161 select HAVE_ASM_MODVERSIONS 162 select HAVE_CMPXCHG_DOUBLE 163 select HAVE_CMPXCHG_LOCAL 164 select HAVE_CONTEXT_TRACKING if X86_64 165 select HAVE_C_RECORDMCOUNT 166 select HAVE_DEBUG_KMEMLEAK 167 select HAVE_DMA_CONTIGUOUS 168 select HAVE_DYNAMIC_FTRACE 169 select HAVE_DYNAMIC_FTRACE_WITH_REGS 170 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 171 select HAVE_EBPF_JIT 172 select HAVE_EFFICIENT_UNALIGNED_ACCESS 173 select HAVE_EISA 174 select HAVE_EXIT_THREAD 175 select HAVE_FAST_GUP 176 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 177 select HAVE_FTRACE_MCOUNT_RECORD 178 select HAVE_FUNCTION_GRAPH_TRACER 179 select HAVE_FUNCTION_TRACER 180 select HAVE_GCC_PLUGINS 181 select HAVE_HW_BREAKPOINT 182 select HAVE_IDE 183 select HAVE_IOREMAP_PROT 184 select HAVE_IRQ_TIME_ACCOUNTING 185 select HAVE_KERNEL_BZIP2 186 select HAVE_KERNEL_GZIP 187 select HAVE_KERNEL_LZ4 188 select HAVE_KERNEL_LZMA 189 select HAVE_KERNEL_LZO 190 select HAVE_KERNEL_XZ 191 select HAVE_KERNEL_ZSTD 192 select HAVE_KPROBES 193 select HAVE_KPROBES_ON_FTRACE 194 select HAVE_FUNCTION_ERROR_INJECTION 195 select HAVE_KRETPROBES 196 select HAVE_KVM 197 select HAVE_LIVEPATCH if X86_64 198 select HAVE_MIXED_BREAKPOINTS_REGS 199 select HAVE_MOD_ARCH_SPECIFIC 200 select HAVE_MOVE_PMD 201 select HAVE_NMI 202 select HAVE_OPROFILE 203 select HAVE_OPTPROBES 204 select HAVE_PCSPKR_PLATFORM 205 select HAVE_PERF_EVENTS 206 select HAVE_PERF_EVENTS_NMI 207 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 208 select HAVE_PCI 209 select HAVE_PERF_REGS 210 select HAVE_PERF_USER_STACK_DUMP 211 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 212 select HAVE_REGS_AND_STACK_ACCESS_API 213 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 214 select HAVE_FUNCTION_ARG_ACCESS_API 215 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 216 select HAVE_STACK_VALIDATION if X86_64 217 select HAVE_RSEQ 218 select HAVE_SYSCALL_TRACEPOINTS 219 select HAVE_UNSTABLE_SCHED_CLOCK 220 select HAVE_USER_RETURN_NOTIFIER 221 select HAVE_GENERIC_VDSO 222 select HOTPLUG_SMT if SMP 223 select IRQ_FORCED_THREADING 224 select NEED_SG_DMA_LENGTH 225 select PCI_DOMAINS if PCI 226 select PCI_LOCKLESS_CONFIG if PCI 227 select PERF_EVENTS 228 select RTC_LIB 229 select RTC_MC146818_LIB 230 select SPARSE_IRQ 231 select SRCU 232 select SYSCTL_EXCEPTION_TRACE 233 select THREAD_INFO_IN_TASK 234 select USER_STACKTRACE_SUPPORT 235 select VIRT_TO_BUS 236 select HAVE_ARCH_KCSAN if X86_64 237 select X86_FEATURE_NAMES if PROC_FS 238 select PROC_PID_ARCH_STATUS if PROC_FS 239 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 240 241config INSTRUCTION_DECODER 242 def_bool y 243 depends on KPROBES || PERF_EVENTS || UPROBES 244 245config OUTPUT_FORMAT 246 string 247 default "elf32-i386" if X86_32 248 default "elf64-x86-64" if X86_64 249 250config LOCKDEP_SUPPORT 251 def_bool y 252 253config STACKTRACE_SUPPORT 254 def_bool y 255 256config MMU 257 def_bool y 258 259config ARCH_MMAP_RND_BITS_MIN 260 default 28 if 64BIT 261 default 8 262 263config ARCH_MMAP_RND_BITS_MAX 264 default 32 if 64BIT 265 default 16 266 267config ARCH_MMAP_RND_COMPAT_BITS_MIN 268 default 8 269 270config ARCH_MMAP_RND_COMPAT_BITS_MAX 271 default 16 272 273config SBUS 274 bool 275 276config GENERIC_ISA_DMA 277 def_bool y 278 depends on ISA_DMA_API 279 280config GENERIC_BUG 281 def_bool y 282 depends on BUG 283 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 284 285config GENERIC_BUG_RELATIVE_POINTERS 286 bool 287 288config ARCH_MAY_HAVE_PC_FDC 289 def_bool y 290 depends on ISA_DMA_API 291 292config GENERIC_CALIBRATE_DELAY 293 def_bool y 294 295config ARCH_HAS_CPU_RELAX 296 def_bool y 297 298config ARCH_HAS_CACHE_LINE_SIZE 299 def_bool y 300 301config ARCH_HAS_FILTER_PGPROT 302 def_bool y 303 304config HAVE_SETUP_PER_CPU_AREA 305 def_bool y 306 307config NEED_PER_CPU_EMBED_FIRST_CHUNK 308 def_bool y 309 310config NEED_PER_CPU_PAGE_FIRST_CHUNK 311 def_bool y 312 313config ARCH_HIBERNATION_POSSIBLE 314 def_bool y 315 316config ARCH_SUSPEND_POSSIBLE 317 def_bool y 318 319config ARCH_WANT_GENERAL_HUGETLB 320 def_bool y 321 322config ZONE_DMA32 323 def_bool y if X86_64 324 325config AUDIT_ARCH 326 def_bool y if X86_64 327 328config ARCH_SUPPORTS_DEBUG_PAGEALLOC 329 def_bool y 330 331config KASAN_SHADOW_OFFSET 332 hex 333 depends on KASAN 334 default 0xdffffc0000000000 335 336config HAVE_INTEL_TXT 337 def_bool y 338 depends on INTEL_IOMMU && ACPI 339 340config X86_32_SMP 341 def_bool y 342 depends on X86_32 && SMP 343 344config X86_64_SMP 345 def_bool y 346 depends on X86_64 && SMP 347 348config X86_32_LAZY_GS 349 def_bool y 350 depends on X86_32 && !STACKPROTECTOR 351 352config ARCH_SUPPORTS_UPROBES 353 def_bool y 354 355config FIX_EARLYCON_MEM 356 def_bool y 357 358config DYNAMIC_PHYSICAL_MASK 359 bool 360 361config PGTABLE_LEVELS 362 int 363 default 5 if X86_5LEVEL 364 default 4 if X86_64 365 default 3 if X86_PAE 366 default 2 367 368config CC_HAS_SANE_STACKPROTECTOR 369 bool 370 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 371 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 372 help 373 We have to make sure stack protector is unconditionally disabled if 374 the compiler produces broken code. 375 376menu "Processor type and features" 377 378config ZONE_DMA 379 bool "DMA memory allocation support" if EXPERT 380 default y 381 help 382 DMA memory allocation support allows devices with less than 32-bit 383 addressing to allocate within the first 16MB of address space. 384 Disable if no such devices will be used. 385 386 If unsure, say Y. 387 388config SMP 389 bool "Symmetric multi-processing support" 390 help 391 This enables support for systems with more than one CPU. If you have 392 a system with only one CPU, say N. If you have a system with more 393 than one CPU, say Y. 394 395 If you say N here, the kernel will run on uni- and multiprocessor 396 machines, but will use only one CPU of a multiprocessor machine. If 397 you say Y here, the kernel will run on many, but not all, 398 uniprocessor machines. On a uniprocessor machine, the kernel 399 will run faster if you say N here. 400 401 Note that if you say Y here and choose architecture "586" or 402 "Pentium" under "Processor family", the kernel will not work on 486 403 architectures. Similarly, multiprocessor kernels for the "PPro" 404 architecture may not work on all Pentium based boards. 405 406 People using multiprocessor machines who say Y here should also say 407 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 408 Management" code will be disabled if you say Y here. 409 410 See also <file:Documentation/x86/i386/IO-APIC.rst>, 411 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 412 <http://www.tldp.org/docs.html#howto>. 413 414 If you don't know what to do here, say N. 415 416config X86_FEATURE_NAMES 417 bool "Processor feature human-readable names" if EMBEDDED 418 default y 419 help 420 This option compiles in a table of x86 feature bits and corresponding 421 names. This is required to support /proc/cpuinfo and a few kernel 422 messages. You can disable this to save space, at the expense of 423 making those few kernel messages show numeric feature bits instead. 424 425 If in doubt, say Y. 426 427config X86_X2APIC 428 bool "Support x2apic" 429 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 430 help 431 This enables x2apic support on CPUs that have this feature. 432 433 This allows 32-bit apic IDs (so it can support very large systems), 434 and accesses the local apic via MSRs not via mmio. 435 436 If you don't know what to do here, say N. 437 438config X86_MPPARSE 439 bool "Enable MPS table" if ACPI || SFI 440 default y 441 depends on X86_LOCAL_APIC 442 help 443 For old smp systems that do not have proper acpi support. Newer systems 444 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 445 446config GOLDFISH 447 def_bool y 448 depends on X86_GOLDFISH 449 450config RETPOLINE 451 bool "Avoid speculative indirect branches in kernel" 452 default y 453 select STACK_VALIDATION if HAVE_STACK_VALIDATION 454 help 455 Compile kernel with the retpoline compiler options to guard against 456 kernel-to-user data leaks by avoiding speculative indirect 457 branches. Requires a compiler with -mindirect-branch=thunk-extern 458 support for full protection. The kernel may run slower. 459 460config X86_CPU_RESCTRL 461 bool "x86 CPU resource control support" 462 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 463 select KERNFS 464 select PROC_CPU_RESCTRL if PROC_FS 465 help 466 Enable x86 CPU resource control support. 467 468 Provide support for the allocation and monitoring of system resources 469 usage by the CPU. 470 471 Intel calls this Intel Resource Director Technology 472 (Intel(R) RDT). More information about RDT can be found in the 473 Intel x86 Architecture Software Developer Manual. 474 475 AMD calls this AMD Platform Quality of Service (AMD QoS). 476 More information about AMD QoS can be found in the AMD64 Technology 477 Platform Quality of Service Extensions manual. 478 479 Say N if unsure. 480 481if X86_32 482config X86_BIGSMP 483 bool "Support for big SMP systems with more than 8 CPUs" 484 depends on SMP 485 help 486 This option is needed for the systems that have more than 8 CPUs. 487 488config X86_EXTENDED_PLATFORM 489 bool "Support for extended (non-PC) x86 platforms" 490 default y 491 help 492 If you disable this option then the kernel will only support 493 standard PC platforms. (which covers the vast majority of 494 systems out there.) 495 496 If you enable this option then you'll be able to select support 497 for the following (non-PC) 32 bit x86 platforms: 498 Goldfish (Android emulator) 499 AMD Elan 500 RDC R-321x SoC 501 SGI 320/540 (Visual Workstation) 502 STA2X11-based (e.g. Northville) 503 Moorestown MID devices 504 505 If you have one of these systems, or if you want to build a 506 generic distribution kernel, say Y here - otherwise say N. 507endif 508 509if X86_64 510config X86_EXTENDED_PLATFORM 511 bool "Support for extended (non-PC) x86 platforms" 512 default y 513 help 514 If you disable this option then the kernel will only support 515 standard PC platforms. (which covers the vast majority of 516 systems out there.) 517 518 If you enable this option then you'll be able to select support 519 for the following (non-PC) 64 bit x86 platforms: 520 Numascale NumaChip 521 ScaleMP vSMP 522 SGI Ultraviolet 523 524 If you have one of these systems, or if you want to build a 525 generic distribution kernel, say Y here - otherwise say N. 526endif 527# This is an alphabetically sorted list of 64 bit extended platforms 528# Please maintain the alphabetic order if and when there are additions 529config X86_NUMACHIP 530 bool "Numascale NumaChip" 531 depends on X86_64 532 depends on X86_EXTENDED_PLATFORM 533 depends on NUMA 534 depends on SMP 535 depends on X86_X2APIC 536 depends on PCI_MMCONFIG 537 help 538 Adds support for Numascale NumaChip large-SMP systems. Needed to 539 enable more than ~168 cores. 540 If you don't have one of these, you should say N here. 541 542config X86_VSMP 543 bool "ScaleMP vSMP" 544 select HYPERVISOR_GUEST 545 select PARAVIRT 546 depends on X86_64 && PCI 547 depends on X86_EXTENDED_PLATFORM 548 depends on SMP 549 help 550 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 551 supposed to run on these EM64T-based machines. Only choose this option 552 if you have one of these machines. 553 554config X86_UV 555 bool "SGI Ultraviolet" 556 depends on X86_64 557 depends on X86_EXTENDED_PLATFORM 558 depends on NUMA 559 depends on EFI 560 depends on X86_X2APIC 561 depends on PCI 562 help 563 This option is needed in order to support SGI Ultraviolet systems. 564 If you don't have one of these, you should say N here. 565 566# Following is an alphabetically sorted list of 32 bit extended platforms 567# Please maintain the alphabetic order if and when there are additions 568 569config X86_GOLDFISH 570 bool "Goldfish (Virtual Platform)" 571 depends on X86_EXTENDED_PLATFORM 572 help 573 Enable support for the Goldfish virtual platform used primarily 574 for Android development. Unless you are building for the Android 575 Goldfish emulator say N here. 576 577config X86_INTEL_CE 578 bool "CE4100 TV platform" 579 depends on PCI 580 depends on PCI_GODIRECT 581 depends on X86_IO_APIC 582 depends on X86_32 583 depends on X86_EXTENDED_PLATFORM 584 select X86_REBOOTFIXUPS 585 select OF 586 select OF_EARLY_FLATTREE 587 help 588 Select for the Intel CE media processor (CE4100) SOC. 589 This option compiles in support for the CE4100 SOC for settop 590 boxes and media devices. 591 592config X86_INTEL_MID 593 bool "Intel MID platform support" 594 depends on X86_EXTENDED_PLATFORM 595 depends on X86_PLATFORM_DEVICES 596 depends on PCI 597 depends on X86_64 || (PCI_GOANY && X86_32) 598 depends on X86_IO_APIC 599 select SFI 600 select I2C 601 select DW_APB_TIMER 602 select APB_TIMER 603 select INTEL_SCU_PCI 604 select MFD_INTEL_MSIC 605 help 606 Select to build a kernel capable of supporting Intel MID (Mobile 607 Internet Device) platform systems which do not have the PCI legacy 608 interfaces. If you are building for a PC class system say N here. 609 610 Intel MID platforms are based on an Intel processor and chipset which 611 consume less power than most of the x86 derivatives. 612 613config X86_INTEL_QUARK 614 bool "Intel Quark platform support" 615 depends on X86_32 616 depends on X86_EXTENDED_PLATFORM 617 depends on X86_PLATFORM_DEVICES 618 depends on X86_TSC 619 depends on PCI 620 depends on PCI_GOANY 621 depends on X86_IO_APIC 622 select IOSF_MBI 623 select INTEL_IMR 624 select COMMON_CLK 625 help 626 Select to include support for Quark X1000 SoC. 627 Say Y here if you have a Quark based system such as the Arduino 628 compatible Intel Galileo. 629 630config X86_INTEL_LPSS 631 bool "Intel Low Power Subsystem Support" 632 depends on X86 && ACPI && PCI 633 select COMMON_CLK 634 select PINCTRL 635 select IOSF_MBI 636 help 637 Select to build support for Intel Low Power Subsystem such as 638 found on Intel Lynxpoint PCH. Selecting this option enables 639 things like clock tree (common clock framework) and pincontrol 640 which are needed by the LPSS peripheral drivers. 641 642config X86_AMD_PLATFORM_DEVICE 643 bool "AMD ACPI2Platform devices support" 644 depends on ACPI 645 select COMMON_CLK 646 select PINCTRL 647 help 648 Select to interpret AMD specific ACPI device to platform device 649 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 650 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 651 implemented under PINCTRL subsystem. 652 653config IOSF_MBI 654 tristate "Intel SoC IOSF Sideband support for SoC platforms" 655 depends on PCI 656 help 657 This option enables sideband register access support for Intel SoC 658 platforms. On these platforms the IOSF sideband is used in lieu of 659 MSR's for some register accesses, mostly but not limited to thermal 660 and power. Drivers may query the availability of this device to 661 determine if they need the sideband in order to work on these 662 platforms. The sideband is available on the following SoC products. 663 This list is not meant to be exclusive. 664 - BayTrail 665 - Braswell 666 - Quark 667 668 You should say Y if you are running a kernel on one of these SoC's. 669 670config IOSF_MBI_DEBUG 671 bool "Enable IOSF sideband access through debugfs" 672 depends on IOSF_MBI && DEBUG_FS 673 help 674 Select this option to expose the IOSF sideband access registers (MCR, 675 MDR, MCRX) through debugfs to write and read register information from 676 different units on the SoC. This is most useful for obtaining device 677 state information for debug and analysis. As this is a general access 678 mechanism, users of this option would have specific knowledge of the 679 device they want to access. 680 681 If you don't require the option or are in doubt, say N. 682 683config X86_RDC321X 684 bool "RDC R-321x SoC" 685 depends on X86_32 686 depends on X86_EXTENDED_PLATFORM 687 select M486 688 select X86_REBOOTFIXUPS 689 help 690 This option is needed for RDC R-321x system-on-chip, also known 691 as R-8610-(G). 692 If you don't have one of these chips, you should say N here. 693 694config X86_32_NON_STANDARD 695 bool "Support non-standard 32-bit SMP architectures" 696 depends on X86_32 && SMP 697 depends on X86_EXTENDED_PLATFORM 698 help 699 This option compiles in the bigsmp and STA2X11 default 700 subarchitectures. It is intended for a generic binary 701 kernel. If you select them all, kernel will probe it one by 702 one and will fallback to default. 703 704# Alphabetically sorted list of Non standard 32 bit platforms 705 706config X86_SUPPORTS_MEMORY_FAILURE 707 def_bool y 708 # MCE code calls memory_failure(): 709 depends on X86_MCE 710 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 711 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 712 depends on X86_64 || !SPARSEMEM 713 select ARCH_SUPPORTS_MEMORY_FAILURE 714 715config STA2X11 716 bool "STA2X11 Companion Chip Support" 717 depends on X86_32_NON_STANDARD && PCI 718 select SWIOTLB 719 select MFD_STA2X11 720 select GPIOLIB 721 help 722 This adds support for boards based on the STA2X11 IO-Hub, 723 a.k.a. "ConneXt". The chip is used in place of the standard 724 PC chipset, so all "standard" peripherals are missing. If this 725 option is selected the kernel will still be able to boot on 726 standard PC machines. 727 728config X86_32_IRIS 729 tristate "Eurobraille/Iris poweroff module" 730 depends on X86_32 731 help 732 The Iris machines from EuroBraille do not have APM or ACPI support 733 to shut themselves down properly. A special I/O sequence is 734 needed to do so, which is what this module does at 735 kernel shutdown. 736 737 This is only for Iris machines from EuroBraille. 738 739 If unused, say N. 740 741config SCHED_OMIT_FRAME_POINTER 742 def_bool y 743 prompt "Single-depth WCHAN output" 744 depends on X86 745 help 746 Calculate simpler /proc/<PID>/wchan values. If this option 747 is disabled then wchan values will recurse back to the 748 caller function. This provides more accurate wchan values, 749 at the expense of slightly more scheduling overhead. 750 751 If in doubt, say "Y". 752 753menuconfig HYPERVISOR_GUEST 754 bool "Linux guest support" 755 help 756 Say Y here to enable options for running Linux under various hyper- 757 visors. This option enables basic hypervisor detection and platform 758 setup. 759 760 If you say N, all options in this submenu will be skipped and 761 disabled, and Linux guest support won't be built in. 762 763if HYPERVISOR_GUEST 764 765config PARAVIRT 766 bool "Enable paravirtualization code" 767 help 768 This changes the kernel so it can modify itself when it is run 769 under a hypervisor, potentially improving performance significantly 770 over full virtualization. However, when run without a hypervisor 771 the kernel is theoretically slower and slightly larger. 772 773config PARAVIRT_XXL 774 bool 775 776config PARAVIRT_DEBUG 777 bool "paravirt-ops debugging" 778 depends on PARAVIRT && DEBUG_KERNEL 779 help 780 Enable to debug paravirt_ops internals. Specifically, BUG if 781 a paravirt_op is missing when it is called. 782 783config PARAVIRT_SPINLOCKS 784 bool "Paravirtualization layer for spinlocks" 785 depends on PARAVIRT && SMP 786 help 787 Paravirtualized spinlocks allow a pvops backend to replace the 788 spinlock implementation with something virtualization-friendly 789 (for example, block the virtual CPU rather than spinning). 790 791 It has a minimal impact on native kernels and gives a nice performance 792 benefit on paravirtualized KVM / Xen kernels. 793 794 If you are unsure how to answer this question, answer Y. 795 796config X86_HV_CALLBACK_VECTOR 797 def_bool n 798 799source "arch/x86/xen/Kconfig" 800 801config KVM_GUEST 802 bool "KVM Guest support (including kvmclock)" 803 depends on PARAVIRT 804 select PARAVIRT_CLOCK 805 select ARCH_CPUIDLE_HALTPOLL 806 select X86_HV_CALLBACK_VECTOR 807 default y 808 help 809 This option enables various optimizations for running under the KVM 810 hypervisor. It includes a paravirtualized clock, so that instead 811 of relying on a PIT (or probably other) emulation by the 812 underlying device model, the host provides the guest with 813 timing infrastructure such as time of day, and system time 814 815config ARCH_CPUIDLE_HALTPOLL 816 def_bool n 817 prompt "Disable host haltpoll when loading haltpoll driver" 818 help 819 If virtualized under KVM, disable host haltpoll. 820 821config PVH 822 bool "Support for running PVH guests" 823 help 824 This option enables the PVH entry point for guest virtual machines 825 as specified in the x86/HVM direct boot ABI. 826 827config PARAVIRT_TIME_ACCOUNTING 828 bool "Paravirtual steal time accounting" 829 depends on PARAVIRT 830 help 831 Select this option to enable fine granularity task steal time 832 accounting. Time spent executing other tasks in parallel with 833 the current vCPU is discounted from the vCPU power. To account for 834 that, there can be a small performance impact. 835 836 If in doubt, say N here. 837 838config PARAVIRT_CLOCK 839 bool 840 841config JAILHOUSE_GUEST 842 bool "Jailhouse non-root cell support" 843 depends on X86_64 && PCI 844 select X86_PM_TIMER 845 help 846 This option allows to run Linux as guest in a Jailhouse non-root 847 cell. You can leave this option disabled if you only want to start 848 Jailhouse and run Linux afterwards in the root cell. 849 850config ACRN_GUEST 851 bool "ACRN Guest support" 852 depends on X86_64 853 select X86_HV_CALLBACK_VECTOR 854 help 855 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 856 a flexible, lightweight reference open-source hypervisor, built with 857 real-time and safety-criticality in mind. It is built for embedded 858 IOT with small footprint and real-time features. More details can be 859 found in https://projectacrn.org/. 860 861endif #HYPERVISOR_GUEST 862 863source "arch/x86/Kconfig.cpu" 864 865config HPET_TIMER 866 def_bool X86_64 867 prompt "HPET Timer Support" if X86_32 868 help 869 Use the IA-PC HPET (High Precision Event Timer) to manage 870 time in preference to the PIT and RTC, if a HPET is 871 present. 872 HPET is the next generation timer replacing legacy 8254s. 873 The HPET provides a stable time base on SMP 874 systems, unlike the TSC, but it is more expensive to access, 875 as it is off-chip. The interface used is documented 876 in the HPET spec, revision 1. 877 878 You can safely choose Y here. However, HPET will only be 879 activated if the platform and the BIOS support this feature. 880 Otherwise the 8254 will be used for timing services. 881 882 Choose N to continue using the legacy 8254 timer. 883 884config HPET_EMULATE_RTC 885 def_bool y 886 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 887 888config APB_TIMER 889 def_bool y if X86_INTEL_MID 890 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 891 select DW_APB_TIMER 892 depends on X86_INTEL_MID && SFI 893 help 894 APB timer is the replacement for 8254, HPET on X86 MID platforms. 895 The APBT provides a stable time base on SMP 896 systems, unlike the TSC, but it is more expensive to access, 897 as it is off-chip. APB timers are always running regardless of CPU 898 C states, they are used as per CPU clockevent device when possible. 899 900# Mark as expert because too many people got it wrong. 901# The code disables itself when not needed. 902config DMI 903 default y 904 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 905 bool "Enable DMI scanning" if EXPERT 906 help 907 Enabled scanning of DMI to identify machine quirks. Say Y 908 here unless you have verified that your setup is not 909 affected by entries in the DMI blacklist. Required by PNP 910 BIOS code. 911 912config GART_IOMMU 913 bool "Old AMD GART IOMMU support" 914 select DMA_OPS 915 select IOMMU_HELPER 916 select SWIOTLB 917 depends on X86_64 && PCI && AMD_NB 918 help 919 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 920 GART based hardware IOMMUs. 921 922 The GART supports full DMA access for devices with 32-bit access 923 limitations, on systems with more than 3 GB. This is usually needed 924 for USB, sound, many IDE/SATA chipsets and some other devices. 925 926 Newer systems typically have a modern AMD IOMMU, supported via 927 the CONFIG_AMD_IOMMU=y config option. 928 929 In normal configurations this driver is only active when needed: 930 there's more than 3 GB of memory and the system contains a 931 32-bit limited device. 932 933 If unsure, say Y. 934 935config MAXSMP 936 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 937 depends on X86_64 && SMP && DEBUG_KERNEL 938 select CPUMASK_OFFSTACK 939 help 940 Enable maximum number of CPUS and NUMA Nodes for this architecture. 941 If unsure, say N. 942 943# 944# The maximum number of CPUs supported: 945# 946# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 947# and which can be configured interactively in the 948# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 949# 950# The ranges are different on 32-bit and 64-bit kernels, depending on 951# hardware capabilities and scalability features of the kernel. 952# 953# ( If MAXSMP is enabled we just use the highest possible value and disable 954# interactive configuration. ) 955# 956 957config NR_CPUS_RANGE_BEGIN 958 int 959 default NR_CPUS_RANGE_END if MAXSMP 960 default 1 if !SMP 961 default 2 962 963config NR_CPUS_RANGE_END 964 int 965 depends on X86_32 966 default 64 if SMP && X86_BIGSMP 967 default 8 if SMP && !X86_BIGSMP 968 default 1 if !SMP 969 970config NR_CPUS_RANGE_END 971 int 972 depends on X86_64 973 default 8192 if SMP && CPUMASK_OFFSTACK 974 default 512 if SMP && !CPUMASK_OFFSTACK 975 default 1 if !SMP 976 977config NR_CPUS_DEFAULT 978 int 979 depends on X86_32 980 default 32 if X86_BIGSMP 981 default 8 if SMP 982 default 1 if !SMP 983 984config NR_CPUS_DEFAULT 985 int 986 depends on X86_64 987 default 8192 if MAXSMP 988 default 64 if SMP 989 default 1 if !SMP 990 991config NR_CPUS 992 int "Maximum number of CPUs" if SMP && !MAXSMP 993 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 994 default NR_CPUS_DEFAULT 995 help 996 This allows you to specify the maximum number of CPUs which this 997 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 998 supported value is 8192, otherwise the maximum value is 512. The 999 minimum value which makes sense is 2. 1000 1001 This is purely to save memory: each supported CPU adds about 8KB 1002 to the kernel image. 1003 1004config SCHED_SMT 1005 def_bool y if SMP 1006 1007config SCHED_MC 1008 def_bool y 1009 prompt "Multi-core scheduler support" 1010 depends on SMP 1011 help 1012 Multi-core scheduler support improves the CPU scheduler's decision 1013 making when dealing with multi-core CPU chips at a cost of slightly 1014 increased overhead in some places. If unsure say N here. 1015 1016config SCHED_MC_PRIO 1017 bool "CPU core priorities scheduler support" 1018 depends on SCHED_MC && CPU_SUP_INTEL 1019 select X86_INTEL_PSTATE 1020 select CPU_FREQ 1021 default y 1022 help 1023 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1024 core ordering determined at manufacturing time, which allows 1025 certain cores to reach higher turbo frequencies (when running 1026 single threaded workloads) than others. 1027 1028 Enabling this kernel feature teaches the scheduler about 1029 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1030 scheduler's CPU selection logic accordingly, so that higher 1031 overall system performance can be achieved. 1032 1033 This feature will have no effect on CPUs without this feature. 1034 1035 If unsure say Y here. 1036 1037config UP_LATE_INIT 1038 def_bool y 1039 depends on !SMP && X86_LOCAL_APIC 1040 1041config X86_UP_APIC 1042 bool "Local APIC support on uniprocessors" if !PCI_MSI 1043 default PCI_MSI 1044 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1045 help 1046 A local APIC (Advanced Programmable Interrupt Controller) is an 1047 integrated interrupt controller in the CPU. If you have a single-CPU 1048 system which has a processor with a local APIC, you can say Y here to 1049 enable and use it. If you say Y here even though your machine doesn't 1050 have a local APIC, then the kernel will still run with no slowdown at 1051 all. The local APIC supports CPU-generated self-interrupts (timer, 1052 performance counters), and the NMI watchdog which detects hard 1053 lockups. 1054 1055config X86_UP_IOAPIC 1056 bool "IO-APIC support on uniprocessors" 1057 depends on X86_UP_APIC 1058 help 1059 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1060 SMP-capable replacement for PC-style interrupt controllers. Most 1061 SMP systems and many recent uniprocessor systems have one. 1062 1063 If you have a single-CPU system with an IO-APIC, you can say Y here 1064 to use it. If you say Y here even though your machine doesn't have 1065 an IO-APIC, then the kernel will still run with no slowdown at all. 1066 1067config X86_LOCAL_APIC 1068 def_bool y 1069 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1070 select IRQ_DOMAIN_HIERARCHY 1071 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1072 1073config X86_IO_APIC 1074 def_bool y 1075 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1076 1077config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1078 bool "Reroute for broken boot IRQs" 1079 depends on X86_IO_APIC 1080 help 1081 This option enables a workaround that fixes a source of 1082 spurious interrupts. This is recommended when threaded 1083 interrupt handling is used on systems where the generation of 1084 superfluous "boot interrupts" cannot be disabled. 1085 1086 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1087 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1088 kernel does during interrupt handling). On chipsets where this 1089 boot IRQ generation cannot be disabled, this workaround keeps 1090 the original IRQ line masked so that only the equivalent "boot 1091 IRQ" is delivered to the CPUs. The workaround also tells the 1092 kernel to set up the IRQ handler on the boot IRQ line. In this 1093 way only one interrupt is delivered to the kernel. Otherwise 1094 the spurious second interrupt may cause the kernel to bring 1095 down (vital) interrupt lines. 1096 1097 Only affects "broken" chipsets. Interrupt sharing may be 1098 increased on these systems. 1099 1100config X86_MCE 1101 bool "Machine Check / overheating reporting" 1102 select GENERIC_ALLOCATOR 1103 default y 1104 help 1105 Machine Check support allows the processor to notify the 1106 kernel if it detects a problem (e.g. overheating, data corruption). 1107 The action the kernel takes depends on the severity of the problem, 1108 ranging from warning messages to halting the machine. 1109 1110config X86_MCELOG_LEGACY 1111 bool "Support for deprecated /dev/mcelog character device" 1112 depends on X86_MCE 1113 help 1114 Enable support for /dev/mcelog which is needed by the old mcelog 1115 userspace logging daemon. Consider switching to the new generation 1116 rasdaemon solution. 1117 1118config X86_MCE_INTEL 1119 def_bool y 1120 prompt "Intel MCE features" 1121 depends on X86_MCE && X86_LOCAL_APIC 1122 help 1123 Additional support for intel specific MCE features such as 1124 the thermal monitor. 1125 1126config X86_MCE_AMD 1127 def_bool y 1128 prompt "AMD MCE features" 1129 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1130 help 1131 Additional support for AMD specific MCE features such as 1132 the DRAM Error Threshold. 1133 1134config X86_ANCIENT_MCE 1135 bool "Support for old Pentium 5 / WinChip machine checks" 1136 depends on X86_32 && X86_MCE 1137 help 1138 Include support for machine check handling on old Pentium 5 or WinChip 1139 systems. These typically need to be enabled explicitly on the command 1140 line. 1141 1142config X86_MCE_THRESHOLD 1143 depends on X86_MCE_AMD || X86_MCE_INTEL 1144 def_bool y 1145 1146config X86_MCE_INJECT 1147 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1148 tristate "Machine check injector support" 1149 help 1150 Provide support for injecting machine checks for testing purposes. 1151 If you don't know what a machine check is and you don't do kernel 1152 QA it is safe to say n. 1153 1154config X86_THERMAL_VECTOR 1155 def_bool y 1156 depends on X86_MCE_INTEL 1157 1158source "arch/x86/events/Kconfig" 1159 1160config X86_LEGACY_VM86 1161 bool "Legacy VM86 support" 1162 depends on X86_32 1163 help 1164 This option allows user programs to put the CPU into V8086 1165 mode, which is an 80286-era approximation of 16-bit real mode. 1166 1167 Some very old versions of X and/or vbetool require this option 1168 for user mode setting. Similarly, DOSEMU will use it if 1169 available to accelerate real mode DOS programs. However, any 1170 recent version of DOSEMU, X, or vbetool should be fully 1171 functional even without kernel VM86 support, as they will all 1172 fall back to software emulation. Nevertheless, if you are using 1173 a 16-bit DOS program where 16-bit performance matters, vm86 1174 mode might be faster than emulation and you might want to 1175 enable this option. 1176 1177 Note that any app that works on a 64-bit kernel is unlikely to 1178 need this option, as 64-bit kernels don't, and can't, support 1179 V8086 mode. This option is also unrelated to 16-bit protected 1180 mode and is not needed to run most 16-bit programs under Wine. 1181 1182 Enabling this option increases the complexity of the kernel 1183 and slows down exception handling a tiny bit. 1184 1185 If unsure, say N here. 1186 1187config VM86 1188 bool 1189 default X86_LEGACY_VM86 1190 1191config X86_16BIT 1192 bool "Enable support for 16-bit segments" if EXPERT 1193 default y 1194 depends on MODIFY_LDT_SYSCALL 1195 help 1196 This option is required by programs like Wine to run 16-bit 1197 protected mode legacy code on x86 processors. Disabling 1198 this option saves about 300 bytes on i386, or around 6K text 1199 plus 16K runtime memory on x86-64, 1200 1201config X86_ESPFIX32 1202 def_bool y 1203 depends on X86_16BIT && X86_32 1204 1205config X86_ESPFIX64 1206 def_bool y 1207 depends on X86_16BIT && X86_64 1208 1209config X86_VSYSCALL_EMULATION 1210 bool "Enable vsyscall emulation" if EXPERT 1211 default y 1212 depends on X86_64 1213 help 1214 This enables emulation of the legacy vsyscall page. Disabling 1215 it is roughly equivalent to booting with vsyscall=none, except 1216 that it will also disable the helpful warning if a program 1217 tries to use a vsyscall. With this option set to N, offending 1218 programs will just segfault, citing addresses of the form 1219 0xffffffffff600?00. 1220 1221 This option is required by many programs built before 2013, and 1222 care should be used even with newer programs if set to N. 1223 1224 Disabling this option saves about 7K of kernel size and 1225 possibly 4K of additional runtime pagetable memory. 1226 1227config X86_IOPL_IOPERM 1228 bool "IOPERM and IOPL Emulation" 1229 default y 1230 help 1231 This enables the ioperm() and iopl() syscalls which are necessary 1232 for legacy applications. 1233 1234 Legacy IOPL support is an overbroad mechanism which allows user 1235 space aside of accessing all 65536 I/O ports also to disable 1236 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1237 capabilities and permission from potentially active security 1238 modules. 1239 1240 The emulation restricts the functionality of the syscall to 1241 only allowing the full range I/O port access, but prevents the 1242 ability to disable interrupts from user space which would be 1243 granted if the hardware IOPL mechanism would be used. 1244 1245config TOSHIBA 1246 tristate "Toshiba Laptop support" 1247 depends on X86_32 1248 help 1249 This adds a driver to safely access the System Management Mode of 1250 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1251 not work on models with a Phoenix BIOS. The System Management Mode 1252 is used to set the BIOS and power saving options on Toshiba portables. 1253 1254 For information on utilities to make use of this driver see the 1255 Toshiba Linux utilities web site at: 1256 <http://www.buzzard.org.uk/toshiba/>. 1257 1258 Say Y if you intend to run this kernel on a Toshiba portable. 1259 Say N otherwise. 1260 1261config I8K 1262 tristate "Dell i8k legacy laptop support" 1263 select HWMON 1264 select SENSORS_DELL_SMM 1265 help 1266 This option enables legacy /proc/i8k userspace interface in hwmon 1267 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1268 temperature and allows controlling fan speeds of Dell laptops via 1269 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1270 it reports also power and hotkey status. For fan speed control is 1271 needed userspace package i8kutils. 1272 1273 Say Y if you intend to run this kernel on old Dell laptops or want to 1274 use userspace package i8kutils. 1275 Say N otherwise. 1276 1277config X86_REBOOTFIXUPS 1278 bool "Enable X86 board specific fixups for reboot" 1279 depends on X86_32 1280 help 1281 This enables chipset and/or board specific fixups to be done 1282 in order to get reboot to work correctly. This is only needed on 1283 some combinations of hardware and BIOS. The symptom, for which 1284 this config is intended, is when reboot ends with a stalled/hung 1285 system. 1286 1287 Currently, the only fixup is for the Geode machines using 1288 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1289 1290 Say Y if you want to enable the fixup. Currently, it's safe to 1291 enable this option even if you don't need it. 1292 Say N otherwise. 1293 1294config MICROCODE 1295 bool "CPU microcode loading support" 1296 default y 1297 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1298 help 1299 If you say Y here, you will be able to update the microcode on 1300 Intel and AMD processors. The Intel support is for the IA32 family, 1301 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1302 AMD support is for families 0x10 and later. You will obviously need 1303 the actual microcode binary data itself which is not shipped with 1304 the Linux kernel. 1305 1306 The preferred method to load microcode from a detached initrd is described 1307 in Documentation/x86/microcode.rst. For that you need to enable 1308 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1309 initrd for microcode blobs. 1310 1311 In addition, you can build the microcode into the kernel. For that you 1312 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1313 config option. 1314 1315config MICROCODE_INTEL 1316 bool "Intel microcode loading support" 1317 depends on MICROCODE 1318 default MICROCODE 1319 help 1320 This options enables microcode patch loading support for Intel 1321 processors. 1322 1323 For the current Intel microcode data package go to 1324 <https://downloadcenter.intel.com> and search for 1325 'Linux Processor Microcode Data File'. 1326 1327config MICROCODE_AMD 1328 bool "AMD microcode loading support" 1329 depends on MICROCODE 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