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