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 select ARCH_HAS_SYSCALL_WRAPPER 34 35config FORCE_DYNAMIC_FTRACE 36 def_bool y 37 depends on X86_32 38 depends on FUNCTION_TRACER 39 select DYNAMIC_FTRACE 40 help 41 We keep the static function tracing (!DYNAMIC_FTRACE) around 42 in order to test the non static function tracing in the 43 generic code, as other architectures still use it. But we 44 only need to keep it around for x86_64. No need to keep it 45 for x86_32. For x86_32, force DYNAMIC_FTRACE. 46# 47# Arch settings 48# 49# ( Note that options that are marked 'if X86_64' could in principle be 50# ported to 32-bit as well. ) 51# 52config X86 53 def_bool y 54 # 55 # Note: keep this list sorted alphabetically 56 # 57 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 58 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 59 select ARCH_32BIT_OFF_T if X86_32 60 select ARCH_CLOCKSOURCE_DATA 61 select ARCH_CLOCKSOURCE_INIT 62 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 63 select ARCH_HAS_DEBUG_VIRTUAL 64 select ARCH_HAS_DEVMEM_IS_ALLOWED 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 71 select ARCH_HAS_MEM_ENCRYPT 72 select ARCH_HAS_MEMBARRIER_SYNC_CORE 73 select ARCH_HAS_PMEM_API if X86_64 74 select ARCH_HAS_PTE_DEVMAP if X86_64 75 select ARCH_HAS_PTE_SPECIAL 76 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 77 select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE 78 select ARCH_HAS_SET_MEMORY 79 select ARCH_HAS_SET_DIRECT_MAP 80 select ARCH_HAS_STRICT_KERNEL_RWX 81 select ARCH_HAS_STRICT_MODULE_RWX 82 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 83 select ARCH_HAS_UBSAN_SANITIZE_ALL 84 select ARCH_HAVE_NMI_SAFE_CMPXCHG 85 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 86 select ARCH_MIGHT_HAVE_PC_PARPORT 87 select ARCH_MIGHT_HAVE_PC_SERIO 88 select ARCH_STACKWALK 89 select ARCH_SUPPORTS_ACPI 90 select ARCH_SUPPORTS_ATOMIC_RMW 91 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 92 select ARCH_USE_BUILTIN_BSWAP 93 select ARCH_USE_QUEUED_RWLOCKS 94 select ARCH_USE_QUEUED_SPINLOCKS 95 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 96 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 97 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 98 select ARCH_WANT_HUGE_PMD_SHARE 99 select ARCH_WANTS_THP_SWAP if X86_64 100 select BUILDTIME_TABLE_SORT 101 select CLKEVT_I8253 102 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 103 select CLOCKSOURCE_WATCHDOG 104 select DCACHE_WORD_ACCESS 105 select EDAC_ATOMIC_SCRUB 106 select EDAC_SUPPORT 107 select GENERIC_CLOCKEVENTS 108 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 109 select GENERIC_CLOCKEVENTS_MIN_ADJUST 110 select GENERIC_CMOS_UPDATE 111 select GENERIC_CPU_AUTOPROBE 112 select GENERIC_CPU_VULNERABILITIES 113 select GENERIC_EARLY_IOREMAP 114 select GENERIC_FIND_FIRST_BIT 115 select GENERIC_IOMAP 116 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 117 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 118 select GENERIC_IRQ_MIGRATION if SMP 119 select GENERIC_IRQ_PROBE 120 select GENERIC_IRQ_RESERVATION_MODE 121 select GENERIC_IRQ_SHOW 122 select GENERIC_PENDING_IRQ if SMP 123 select GENERIC_SMP_IDLE_THREAD 124 select GENERIC_STRNCPY_FROM_USER 125 select GENERIC_STRNLEN_USER 126 select GENERIC_TIME_VSYSCALL 127 select GENERIC_GETTIMEOFDAY 128 select GENERIC_VDSO_TIME_NS 129 select GUP_GET_PTE_LOW_HIGH if X86_PAE 130 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 131 select HAVE_ACPI_APEI if ACPI 132 select HAVE_ACPI_APEI_NMI if ACPI 133 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 134 select HAVE_ARCH_AUDITSYSCALL 135 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 136 select HAVE_ARCH_JUMP_LABEL 137 select HAVE_ARCH_JUMP_LABEL_RELATIVE 138 select HAVE_ARCH_KASAN if X86_64 139 select HAVE_ARCH_KASAN_VMALLOC if X86_64 140 select HAVE_ARCH_KGDB 141 select HAVE_ARCH_MMAP_RND_BITS if MMU 142 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 143 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 144 select HAVE_ARCH_PREL32_RELOCATIONS 145 select HAVE_ARCH_SECCOMP_FILTER 146 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 147 select HAVE_ARCH_STACKLEAK 148 select HAVE_ARCH_TRACEHOOK 149 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 150 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 151 select HAVE_ARCH_VMAP_STACK if X86_64 152 select HAVE_ARCH_WITHIN_STACK_FRAMES 153 select HAVE_ASM_MODVERSIONS 154 select HAVE_CMPXCHG_DOUBLE 155 select HAVE_CMPXCHG_LOCAL 156 select HAVE_CONTEXT_TRACKING if X86_64 157 select HAVE_COPY_THREAD_TLS 158 select HAVE_C_RECORDMCOUNT 159 select HAVE_DEBUG_KMEMLEAK 160 select HAVE_DMA_CONTIGUOUS 161 select HAVE_DYNAMIC_FTRACE 162 select HAVE_DYNAMIC_FTRACE_WITH_REGS 163 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 164 select HAVE_EBPF_JIT 165 select HAVE_EFFICIENT_UNALIGNED_ACCESS 166 select HAVE_EISA 167 select HAVE_EXIT_THREAD 168 select HAVE_FAST_GUP 169 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 170 select HAVE_FTRACE_MCOUNT_RECORD 171 select HAVE_FUNCTION_GRAPH_TRACER 172 select HAVE_FUNCTION_TRACER 173 select HAVE_GCC_PLUGINS 174 select HAVE_HW_BREAKPOINT 175 select HAVE_IDE 176 select HAVE_IOREMAP_PROT 177 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 178 select HAVE_IRQ_TIME_ACCOUNTING 179 select HAVE_KERNEL_BZIP2 180 select HAVE_KERNEL_GZIP 181 select HAVE_KERNEL_LZ4 182 select HAVE_KERNEL_LZMA 183 select HAVE_KERNEL_LZO 184 select HAVE_KERNEL_XZ 185 select HAVE_KPROBES 186 select HAVE_KPROBES_ON_FTRACE 187 select HAVE_FUNCTION_ERROR_INJECTION 188 select HAVE_KRETPROBES 189 select HAVE_KVM 190 select HAVE_LIVEPATCH if X86_64 191 select HAVE_MEMBLOCK_NODE_MAP 192 select HAVE_MIXED_BREAKPOINTS_REGS 193 select HAVE_MOD_ARCH_SPECIFIC 194 select HAVE_MOVE_PMD 195 select HAVE_NMI 196 select HAVE_OPROFILE 197 select HAVE_OPTPROBES 198 select HAVE_PCSPKR_PLATFORM 199 select HAVE_PERF_EVENTS 200 select HAVE_PERF_EVENTS_NMI 201 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 202 select HAVE_PCI 203 select HAVE_PERF_REGS 204 select HAVE_PERF_USER_STACK_DUMP 205 select HAVE_RCU_TABLE_FREE if PARAVIRT 206 select HAVE_REGS_AND_STACK_ACCESS_API 207 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 208 select HAVE_FUNCTION_ARG_ACCESS_API 209 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 210 select HAVE_STACK_VALIDATION if X86_64 211 select HAVE_RSEQ 212 select HAVE_SYSCALL_TRACEPOINTS 213 select HAVE_UNSTABLE_SCHED_CLOCK 214 select HAVE_USER_RETURN_NOTIFIER 215 select HAVE_GENERIC_VDSO 216 select HOTPLUG_SMT if SMP 217 select IRQ_FORCED_THREADING 218 select NEED_SG_DMA_LENGTH 219 select PCI_DOMAINS if PCI 220 select PCI_LOCKLESS_CONFIG if PCI 221 select PERF_EVENTS 222 select RTC_LIB 223 select RTC_MC146818_LIB 224 select SPARSE_IRQ 225 select SRCU 226 select SYSCTL_EXCEPTION_TRACE 227 select THREAD_INFO_IN_TASK 228 select USER_STACKTRACE_SUPPORT 229 select VIRT_TO_BUS 230 select X86_FEATURE_NAMES if PROC_FS 231 select PROC_PID_ARCH_STATUS if PROC_FS 232 233config INSTRUCTION_DECODER 234 def_bool y 235 depends on KPROBES || PERF_EVENTS || UPROBES 236 237config OUTPUT_FORMAT 238 string 239 default "elf32-i386" if X86_32 240 default "elf64-x86-64" if X86_64 241 242config ARCH_DEFCONFIG 243 string 244 default "arch/x86/configs/i386_defconfig" if X86_32 245 default "arch/x86/configs/x86_64_defconfig" if X86_64 246 247config LOCKDEP_SUPPORT 248 def_bool y 249 250config STACKTRACE_SUPPORT 251 def_bool y 252 253config MMU 254 def_bool y 255 256config ARCH_MMAP_RND_BITS_MIN 257 default 28 if 64BIT 258 default 8 259 260config ARCH_MMAP_RND_BITS_MAX 261 default 32 if 64BIT 262 default 16 263 264config ARCH_MMAP_RND_COMPAT_BITS_MIN 265 default 8 266 267config ARCH_MMAP_RND_COMPAT_BITS_MAX 268 default 16 269 270config SBUS 271 bool 272 273config GENERIC_ISA_DMA 274 def_bool y 275 depends on ISA_DMA_API 276 277config GENERIC_BUG 278 def_bool y 279 depends on BUG 280 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 281 282config GENERIC_BUG_RELATIVE_POINTERS 283 bool 284 285config ARCH_MAY_HAVE_PC_FDC 286 def_bool y 287 depends on ISA_DMA_API 288 289config GENERIC_CALIBRATE_DELAY 290 def_bool y 291 292config ARCH_HAS_CPU_RELAX 293 def_bool y 294 295config ARCH_HAS_CACHE_LINE_SIZE 296 def_bool y 297 298config ARCH_HAS_FILTER_PGPROT 299 def_bool y 300 301config HAVE_SETUP_PER_CPU_AREA 302 def_bool y 303 304config NEED_PER_CPU_EMBED_FIRST_CHUNK 305 def_bool y 306 307config NEED_PER_CPU_PAGE_FIRST_CHUNK 308 def_bool y 309 310config ARCH_HIBERNATION_POSSIBLE 311 def_bool y 312 313config ARCH_SUSPEND_POSSIBLE 314 def_bool y 315 316config ARCH_WANT_GENERAL_HUGETLB 317 def_bool y 318 319config ZONE_DMA32 320 def_bool y if X86_64 321 322config AUDIT_ARCH 323 def_bool y if X86_64 324 325config ARCH_SUPPORTS_DEBUG_PAGEALLOC 326 def_bool y 327 328config KASAN_SHADOW_OFFSET 329 hex 330 depends on KASAN 331 default 0xdffffc0000000000 332 333config HAVE_INTEL_TXT 334 def_bool y 335 depends on INTEL_IOMMU && ACPI 336 337config X86_32_SMP 338 def_bool y 339 depends on X86_32 && SMP 340 341config X86_64_SMP 342 def_bool y 343 depends on X86_64 && SMP 344 345config X86_32_LAZY_GS 346 def_bool y 347 depends on X86_32 && !STACKPROTECTOR 348 349config ARCH_SUPPORTS_UPROBES 350 def_bool y 351 352config FIX_EARLYCON_MEM 353 def_bool y 354 355config DYNAMIC_PHYSICAL_MASK 356 bool 357 358config PGTABLE_LEVELS 359 int 360 default 5 if X86_5LEVEL 361 default 4 if X86_64 362 default 3 if X86_PAE 363 default 2 364 365config CC_HAS_SANE_STACKPROTECTOR 366 bool 367 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 368 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 369 help 370 We have to make sure stack protector is unconditionally disabled if 371 the compiler produces broken code. 372 373menu "Processor type and features" 374 375config ZONE_DMA 376 bool "DMA memory allocation support" if EXPERT 377 default y 378 help 379 DMA memory allocation support allows devices with less than 32-bit 380 addressing to allocate within the first 16MB of address space. 381 Disable if no such devices will be used. 382 383 If unsure, say Y. 384 385config SMP 386 bool "Symmetric multi-processing support" 387 ---help--- 388 This enables support for systems with more than one CPU. If you have 389 a system with only one CPU, say N. If you have a system with more 390 than one CPU, say Y. 391 392 If you say N here, the kernel will run on uni- and multiprocessor 393 machines, but will use only one CPU of a multiprocessor machine. If 394 you say Y here, the kernel will run on many, but not all, 395 uniprocessor machines. On a uniprocessor machine, the kernel 396 will run faster if you say N here. 397 398 Note that if you say Y here and choose architecture "586" or 399 "Pentium" under "Processor family", the kernel will not work on 486 400 architectures. Similarly, multiprocessor kernels for the "PPro" 401 architecture may not work on all Pentium based boards. 402 403 People using multiprocessor machines who say Y here should also say 404 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 405 Management" code will be disabled if you say Y here. 406 407 See also <file:Documentation/x86/i386/IO-APIC.rst>, 408 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 409 <http://www.tldp.org/docs.html#howto>. 410 411 If you don't know what to do here, say N. 412 413config X86_FEATURE_NAMES 414 bool "Processor feature human-readable names" if EMBEDDED 415 default y 416 ---help--- 417 This option compiles in a table of x86 feature bits and corresponding 418 names. This is required to support /proc/cpuinfo and a few kernel 419 messages. You can disable this to save space, at the expense of 420 making those few kernel messages show numeric feature bits instead. 421 422 If in doubt, say Y. 423 424config X86_X2APIC 425 bool "Support x2apic" 426 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 427 ---help--- 428 This enables x2apic support on CPUs that have this feature. 429 430 This allows 32-bit apic IDs (so it can support very large systems), 431 and accesses the local apic via MSRs not via mmio. 432 433 If you don't know what to do here, say N. 434 435config X86_MPPARSE 436 bool "Enable MPS table" if ACPI || SFI 437 default y 438 depends on X86_LOCAL_APIC 439 ---help--- 440 For old smp systems that do not have proper acpi support. Newer systems 441 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 442 443config GOLDFISH 444 def_bool y 445 depends on X86_GOLDFISH 446 447config RETPOLINE 448 bool "Avoid speculative indirect branches in kernel" 449 default y 450 select STACK_VALIDATION if HAVE_STACK_VALIDATION 451 help 452 Compile kernel with the retpoline compiler options to guard against 453 kernel-to-user data leaks by avoiding speculative indirect 454 branches. Requires a compiler with -mindirect-branch=thunk-extern 455 support for full protection. The kernel may run slower. 456 457config X86_CPU_RESCTRL 458 bool "x86 CPU resource control support" 459 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 460 select KERNFS 461 select PROC_CPU_RESCTRL if PROC_FS 462 help 463 Enable x86 CPU resource control support. 464 465 Provide support for the allocation and monitoring of system resources 466 usage by the CPU. 467 468 Intel calls this Intel Resource Director Technology 469 (Intel(R) RDT). More information about RDT can be found in the 470 Intel x86 Architecture Software Developer Manual. 471 472 AMD calls this AMD Platform Quality of Service (AMD QoS). 473 More information about AMD QoS can be found in the AMD64 Technology 474 Platform Quality of Service Extensions manual. 475 476 Say N if unsure. 477 478if X86_32 479config X86_BIGSMP 480 bool "Support for big SMP systems with more than 8 CPUs" 481 depends on SMP 482 ---help--- 483 This option is needed for the systems that have more than 8 CPUs. 484 485config X86_EXTENDED_PLATFORM 486 bool "Support for extended (non-PC) x86 platforms" 487 default y 488 ---help--- 489 If you disable this option then the kernel will only support 490 standard PC platforms. (which covers the vast majority of 491 systems out there.) 492 493 If you enable this option then you'll be able to select support 494 for the following (non-PC) 32 bit x86 platforms: 495 Goldfish (Android emulator) 496 AMD Elan 497 RDC R-321x SoC 498 SGI 320/540 (Visual Workstation) 499 STA2X11-based (e.g. Northville) 500 Moorestown MID devices 501 502 If you have one of these systems, or if you want to build a 503 generic distribution kernel, say Y here - otherwise say N. 504endif 505 506if X86_64 507config X86_EXTENDED_PLATFORM 508 bool "Support for extended (non-PC) x86 platforms" 509 default y 510 ---help--- 511 If you disable this option then the kernel will only support 512 standard PC platforms. (which covers the vast majority of 513 systems out there.) 514 515 If you enable this option then you'll be able to select support 516 for the following (non-PC) 64 bit x86 platforms: 517 Numascale NumaChip 518 ScaleMP vSMP 519 SGI Ultraviolet 520 521 If you have one of these systems, or if you want to build a 522 generic distribution kernel, say Y here - otherwise say N. 523endif 524# This is an alphabetically sorted list of 64 bit extended platforms 525# Please maintain the alphabetic order if and when there are additions 526config X86_NUMACHIP 527 bool "Numascale NumaChip" 528 depends on X86_64 529 depends on X86_EXTENDED_PLATFORM 530 depends on NUMA 531 depends on SMP 532 depends on X86_X2APIC 533 depends on PCI_MMCONFIG 534 ---help--- 535 Adds support for Numascale NumaChip large-SMP systems. Needed to 536 enable more than ~168 cores. 537 If you don't have one of these, you should say N here. 538 539config X86_VSMP 540 bool "ScaleMP vSMP" 541 select HYPERVISOR_GUEST 542 select PARAVIRT 543 depends on X86_64 && PCI 544 depends on X86_EXTENDED_PLATFORM 545 depends on SMP 546 ---help--- 547 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 548 supposed to run on these EM64T-based machines. Only choose this option 549 if you have one of these machines. 550 551config X86_UV 552 bool "SGI Ultraviolet" 553 depends on X86_64 554 depends on X86_EXTENDED_PLATFORM 555 depends on NUMA 556 depends on EFI 557 depends on X86_X2APIC 558 depends on PCI 559 ---help--- 560 This option is needed in order to support SGI Ultraviolet systems. 561 If you don't have one of these, you should say N here. 562 563# Following is an alphabetically sorted list of 32 bit extended platforms 564# Please maintain the alphabetic order if and when there are additions 565 566config X86_GOLDFISH 567 bool "Goldfish (Virtual Platform)" 568 depends on X86_EXTENDED_PLATFORM 569 ---help--- 570 Enable support for the Goldfish virtual platform used primarily 571 for Android development. Unless you are building for the Android 572 Goldfish emulator say N here. 573 574config X86_INTEL_CE 575 bool "CE4100 TV platform" 576 depends on PCI 577 depends on PCI_GODIRECT 578 depends on X86_IO_APIC 579 depends on X86_32 580 depends on X86_EXTENDED_PLATFORM 581 select X86_REBOOTFIXUPS 582 select OF 583 select OF_EARLY_FLATTREE 584 ---help--- 585 Select for the Intel CE media processor (CE4100) SOC. 586 This option compiles in support for the CE4100 SOC for settop 587 boxes and media devices. 588 589config X86_INTEL_MID 590 bool "Intel MID platform support" 591 depends on X86_EXTENDED_PLATFORM 592 depends on X86_PLATFORM_DEVICES 593 depends on PCI 594 depends on X86_64 || (PCI_GOANY && X86_32) 595 depends on X86_IO_APIC 596 select SFI 597 select I2C 598 select DW_APB_TIMER 599 select APB_TIMER 600 select INTEL_SCU_IPC 601 select MFD_INTEL_MSIC 602 ---help--- 603 Select to build a kernel capable of supporting Intel MID (Mobile 604 Internet Device) platform systems which do not have the PCI legacy 605 interfaces. If you are building for a PC class system say N here. 606 607 Intel MID platforms are based on an Intel processor and chipset which 608 consume less power than most of the x86 derivatives. 609 610config X86_INTEL_QUARK 611 bool "Intel Quark platform support" 612 depends on X86_32 613 depends on X86_EXTENDED_PLATFORM 614 depends on X86_PLATFORM_DEVICES 615 depends on X86_TSC 616 depends on PCI 617 depends on PCI_GOANY 618 depends on X86_IO_APIC 619 select IOSF_MBI 620 select INTEL_IMR 621 select COMMON_CLK 622 ---help--- 623 Select to include support for Quark X1000 SoC. 624 Say Y here if you have a Quark based system such as the Arduino 625 compatible Intel Galileo. 626 627config X86_INTEL_LPSS 628 bool "Intel Low Power Subsystem Support" 629 depends on X86 && ACPI && PCI 630 select COMMON_CLK 631 select PINCTRL 632 select IOSF_MBI 633 ---help--- 634 Select to build support for Intel Low Power Subsystem such as 635 found on Intel Lynxpoint PCH. Selecting this option enables 636 things like clock tree (common clock framework) and pincontrol 637 which are needed by the LPSS peripheral drivers. 638 639config X86_AMD_PLATFORM_DEVICE 640 bool "AMD ACPI2Platform devices support" 641 depends on ACPI 642 select COMMON_CLK 643 select PINCTRL 644 ---help--- 645 Select to interpret AMD specific ACPI device to platform device 646 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 647 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 648 implemented under PINCTRL subsystem. 649 650config IOSF_MBI 651 tristate "Intel SoC IOSF Sideband support for SoC platforms" 652 depends on PCI 653 ---help--- 654 This option enables sideband register access support for Intel SoC 655 platforms. On these platforms the IOSF sideband is used in lieu of 656 MSR's for some register accesses, mostly but not limited to thermal 657 and power. Drivers may query the availability of this device to 658 determine if they need the sideband in order to work on these 659 platforms. The sideband is available on the following SoC products. 660 This list is not meant to be exclusive. 661 - BayTrail 662 - Braswell 663 - Quark 664 665 You should say Y if you are running a kernel on one of these SoC's. 666 667config IOSF_MBI_DEBUG 668 bool "Enable IOSF sideband access through debugfs" 669 depends on IOSF_MBI && DEBUG_FS 670 ---help--- 671 Select this option to expose the IOSF sideband access registers (MCR, 672 MDR, MCRX) through debugfs to write and read register information from 673 different units on the SoC. This is most useful for obtaining device 674 state information for debug and analysis. As this is a general access 675 mechanism, users of this option would have specific knowledge of the 676 device they want to access. 677 678 If you don't require the option or are in doubt, say N. 679 680config X86_RDC321X 681 bool "RDC R-321x SoC" 682 depends on X86_32 683 depends on X86_EXTENDED_PLATFORM 684 select M486 685 select X86_REBOOTFIXUPS 686 ---help--- 687 This option is needed for RDC R-321x system-on-chip, also known 688 as R-8610-(G). 689 If you don't have one of these chips, you should say N here. 690 691config X86_32_NON_STANDARD 692 bool "Support non-standard 32-bit SMP architectures" 693 depends on X86_32 && SMP 694 depends on X86_EXTENDED_PLATFORM 695 ---help--- 696 This option compiles in the bigsmp and STA2X11 default 697 subarchitectures. It is intended for a generic binary 698 kernel. If you select them all, kernel will probe it one by 699 one and will fallback to default. 700 701# Alphabetically sorted list of Non standard 32 bit platforms 702 703config X86_SUPPORTS_MEMORY_FAILURE 704 def_bool y 705 # MCE code calls memory_failure(): 706 depends on X86_MCE 707 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 708 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 709 depends on X86_64 || !SPARSEMEM 710 select ARCH_SUPPORTS_MEMORY_FAILURE 711 712config STA2X11 713 bool "STA2X11 Companion Chip Support" 714 depends on X86_32_NON_STANDARD && PCI 715 select SWIOTLB 716 select MFD_STA2X11 717 select GPIOLIB 718 ---help--- 719 This adds support for boards based on the STA2X11 IO-Hub, 720 a.k.a. "ConneXt". The chip is used in place of the standard 721 PC chipset, so all "standard" peripherals are missing. If this 722 option is selected the kernel will still be able to boot on 723 standard PC machines. 724 725config X86_32_IRIS 726 tristate "Eurobraille/Iris poweroff module" 727 depends on X86_32 728 ---help--- 729 The Iris machines from EuroBraille do not have APM or ACPI support 730 to shut themselves down properly. A special I/O sequence is 731 needed to do so, which is what this module does at 732 kernel shutdown. 733 734 This is only for Iris machines from EuroBraille. 735 736 If unused, say N. 737 738config SCHED_OMIT_FRAME_POINTER 739 def_bool y 740 prompt "Single-depth WCHAN output" 741 depends on X86 742 ---help--- 743 Calculate simpler /proc/<PID>/wchan values. If this option 744 is disabled then wchan values will recurse back to the 745 caller function. This provides more accurate wchan values, 746 at the expense of slightly more scheduling overhead. 747 748 If in doubt, say "Y". 749 750menuconfig HYPERVISOR_GUEST 751 bool "Linux guest support" 752 ---help--- 753 Say Y here to enable options for running Linux under various hyper- 754 visors. This option enables basic hypervisor detection and platform 755 setup. 756 757 If you say N, all options in this submenu will be skipped and 758 disabled, and Linux guest support won't be built in. 759 760if HYPERVISOR_GUEST 761 762config PARAVIRT 763 bool "Enable paravirtualization code" 764 ---help--- 765 This changes the kernel so it can modify itself when it is run 766 under a hypervisor, potentially improving performance significantly 767 over full virtualization. However, when run without a hypervisor 768 the kernel is theoretically slower and slightly larger. 769 770config PARAVIRT_XXL 771 bool 772 773config PARAVIRT_DEBUG 774 bool "paravirt-ops debugging" 775 depends on PARAVIRT && DEBUG_KERNEL 776 ---help--- 777 Enable to debug paravirt_ops internals. Specifically, BUG if 778 a paravirt_op is missing when it is called. 779 780config PARAVIRT_SPINLOCKS 781 bool "Paravirtualization layer for spinlocks" 782 depends on PARAVIRT && SMP 783 ---help--- 784 Paravirtualized spinlocks allow a pvops backend to replace the 785 spinlock implementation with something virtualization-friendly 786 (for example, block the virtual CPU rather than spinning). 787 788 It has a minimal impact on native kernels and gives a nice performance 789 benefit on paravirtualized KVM / Xen kernels. 790 791 If you are unsure how to answer this question, answer Y. 792 793config X86_HV_CALLBACK_VECTOR 794 def_bool n 795 796source "arch/x86/xen/Kconfig" 797 798config KVM_GUEST 799 bool "KVM Guest support (including kvmclock)" 800 depends on PARAVIRT 801 select PARAVIRT_CLOCK 802 select ARCH_CPUIDLE_HALTPOLL 803 default y 804 ---help--- 805 This option enables various optimizations for running under the KVM 806 hypervisor. It includes a paravirtualized clock, so that instead 807 of relying on a PIT (or probably other) emulation by the 808 underlying device model, the host provides the guest with 809 timing infrastructure such as time of day, and system time 810 811config ARCH_CPUIDLE_HALTPOLL 812 def_bool n 813 prompt "Disable host haltpoll when loading haltpoll driver" 814 help 815 If virtualized under KVM, disable host haltpoll. 816 817config PVH 818 bool "Support for running PVH guests" 819 ---help--- 820 This option enables the PVH entry point for guest virtual machines 821 as specified in the x86/HVM direct boot ABI. 822 823config KVM_DEBUG_FS 824 bool "Enable debug information for KVM Guests in debugfs" 825 depends on KVM_GUEST && DEBUG_FS 826 ---help--- 827 This option enables collection of various statistics for KVM guest. 828 Statistics are displayed in debugfs filesystem. Enabling this option 829 may incur significant overhead. 830 831config PARAVIRT_TIME_ACCOUNTING 832 bool "Paravirtual steal time accounting" 833 depends on PARAVIRT 834 ---help--- 835 Select this option to enable fine granularity task steal time 836 accounting. Time spent executing other tasks in parallel with 837 the current vCPU is discounted from the vCPU power. To account for 838 that, there can be a small performance impact. 839 840 If in doubt, say N here. 841 842config PARAVIRT_CLOCK 843 bool 844 845config JAILHOUSE_GUEST 846 bool "Jailhouse non-root cell support" 847 depends on X86_64 && PCI 848 select X86_PM_TIMER 849 ---help--- 850 This option allows to run Linux as guest in a Jailhouse non-root 851 cell. You can leave this option disabled if you only want to start 852 Jailhouse and run Linux afterwards in the root cell. 853 854config ACRN_GUEST 855 bool "ACRN Guest support" 856 depends on X86_64 857 select X86_HV_CALLBACK_VECTOR 858 help 859 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 860 a flexible, lightweight reference open-source hypervisor, built with 861 real-time and safety-criticality in mind. It is built for embedded 862 IOT with small footprint and real-time features. More details can be 863 found in https://projectacrn.org/. 864 865endif #HYPERVISOR_GUEST 866 867source "arch/x86/Kconfig.cpu" 868 869config HPET_TIMER 870 def_bool X86_64 871 prompt "HPET Timer Support" if X86_32 872 ---help--- 873 Use the IA-PC HPET (High Precision Event Timer) to manage 874 time in preference to the PIT and RTC, if a HPET is 875 present. 876 HPET is the next generation timer replacing legacy 8254s. 877 The HPET provides a stable time base on SMP 878 systems, unlike the TSC, but it is more expensive to access, 879 as it is off-chip. The interface used is documented 880 in the HPET spec, revision 1. 881 882 You can safely choose Y here. However, HPET will only be 883 activated if the platform and the BIOS support this feature. 884 Otherwise the 8254 will be used for timing services. 885 886 Choose N to continue using the legacy 8254 timer. 887 888config HPET_EMULATE_RTC 889 def_bool y 890 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 891 892config APB_TIMER 893 def_bool y if X86_INTEL_MID 894 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 895 select DW_APB_TIMER 896 depends on X86_INTEL_MID && SFI 897 help 898 APB timer is the replacement for 8254, HPET on X86 MID platforms. 899 The APBT provides a stable time base on SMP 900 systems, unlike the TSC, but it is more expensive to access, 901 as it is off-chip. APB timers are always running regardless of CPU 902 C states, they are used as per CPU clockevent device when possible. 903 904# Mark as expert because too many people got it wrong. 905# The code disables itself when not needed. 906config DMI 907 default y 908 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 909 bool "Enable DMI scanning" if EXPERT 910 ---help--- 911 Enabled scanning of DMI to identify machine quirks. Say Y 912 here unless you have verified that your setup is not 913 affected by entries in the DMI blacklist. Required by PNP 914 BIOS code. 915 916config GART_IOMMU 917 bool "Old AMD GART IOMMU support" 918 select IOMMU_HELPER 919 select SWIOTLB 920 depends on X86_64 && PCI && AMD_NB 921 ---help--- 922 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 923 GART based hardware IOMMUs. 924 925 The GART supports full DMA access for devices with 32-bit access 926 limitations, on systems with more than 3 GB. This is usually needed 927 for USB, sound, many IDE/SATA chipsets and some other devices. 928 929 Newer systems typically have a modern AMD IOMMU, supported via 930 the CONFIG_AMD_IOMMU=y config option. 931 932 In normal configurations this driver is only active when needed: 933 there's more than 3 GB of memory and the system contains a 934 32-bit limited device. 935 936 If unsure, say Y. 937 938config MAXSMP 939 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 940 depends on X86_64 && SMP && DEBUG_KERNEL 941 select CPUMASK_OFFSTACK 942 ---help--- 943 Enable maximum number of CPUS and NUMA Nodes for this architecture. 944 If unsure, say N. 945 946# 947# The maximum number of CPUs supported: 948# 949# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 950# and which can be configured interactively in the 951# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 952# 953# The ranges are different on 32-bit and 64-bit kernels, depending on 954# hardware capabilities and scalability features of the kernel. 955# 956# ( If MAXSMP is enabled we just use the highest possible value and disable 957# interactive configuration. ) 958# 959 960config NR_CPUS_RANGE_BEGIN 961 int 962 default NR_CPUS_RANGE_END if MAXSMP 963 default 1 if !SMP 964 default 2 965 966config NR_CPUS_RANGE_END 967 int 968 depends on X86_32 969 default 64 if SMP && X86_BIGSMP 970 default 8 if SMP && !X86_BIGSMP 971 default 1 if !SMP 972 973config NR_CPUS_RANGE_END 974 int 975 depends on X86_64 976 default 8192 if SMP && CPUMASK_OFFSTACK 977 default 512 if SMP && !CPUMASK_OFFSTACK 978 default 1 if !SMP 979 980config NR_CPUS_DEFAULT 981 int 982 depends on X86_32 983 default 32 if X86_BIGSMP 984 default 8 if SMP 985 default 1 if !SMP 986 987config NR_CPUS_DEFAULT 988 int 989 depends on X86_64 990 default 8192 if MAXSMP 991 default 64 if SMP 992 default 1 if !SMP 993 994config NR_CPUS 995 int "Maximum number of CPUs" if SMP && !MAXSMP 996 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 997 default NR_CPUS_DEFAULT 998 ---help--- 999 This allows you to specify the maximum number of CPUs which this 1000 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1001 supported value is 8192, otherwise the maximum value is 512. The 1002 minimum value which makes sense is 2. 1003 1004 This is purely to save memory: each supported CPU adds about 8KB 1005 to the kernel image. 1006 1007config SCHED_SMT 1008 def_bool y if SMP 1009 1010config SCHED_MC 1011 def_bool y 1012 prompt "Multi-core scheduler support" 1013 depends on SMP 1014 ---help--- 1015 Multi-core scheduler support improves the CPU scheduler's decision 1016 making when dealing with multi-core CPU chips at a cost of slightly 1017 increased overhead in some places. If unsure say N here. 1018 1019config SCHED_MC_PRIO 1020 bool "CPU core priorities scheduler support" 1021 depends on SCHED_MC && CPU_SUP_INTEL 1022 select X86_INTEL_PSTATE 1023 select CPU_FREQ 1024 default y 1025 ---help--- 1026 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1027 core ordering determined at manufacturing time, which allows 1028 certain cores to reach higher turbo frequencies (when running 1029 single threaded workloads) than others. 1030 1031 Enabling this kernel feature teaches the scheduler about 1032 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1033 scheduler's CPU selection logic accordingly, so that higher 1034 overall system performance can be achieved. 1035 1036 This feature will have no effect on CPUs without this feature. 1037 1038 If unsure say Y here. 1039 1040config UP_LATE_INIT 1041 def_bool y 1042 depends on !SMP && X86_LOCAL_APIC 1043 1044config X86_UP_APIC 1045 bool "Local APIC support on uniprocessors" if !PCI_MSI 1046 default PCI_MSI 1047 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1048 ---help--- 1049 A local APIC (Advanced Programmable Interrupt Controller) is an 1050 integrated interrupt controller in the CPU. If you have a single-CPU 1051 system which has a processor with a local APIC, you can say Y here to 1052 enable and use it. If you say Y here even though your machine doesn't 1053 have a local APIC, then the kernel will still run with no slowdown at 1054 all. The local APIC supports CPU-generated self-interrupts (timer, 1055 performance counters), and the NMI watchdog which detects hard 1056 lockups. 1057 1058config X86_UP_IOAPIC 1059 bool "IO-APIC support on uniprocessors" 1060 depends on X86_UP_APIC 1061 ---help--- 1062 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1063 SMP-capable replacement for PC-style interrupt controllers. Most 1064 SMP systems and many recent uniprocessor systems have one. 1065 1066 If you have a single-CPU system with an IO-APIC, you can say Y here 1067 to use it. If you say Y here even though your machine doesn't have 1068 an IO-APIC, then the kernel will still run with no slowdown at all. 1069 1070config X86_LOCAL_APIC 1071 def_bool y 1072 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1073 select IRQ_DOMAIN_HIERARCHY 1074 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1075 1076config X86_IO_APIC 1077 def_bool y 1078 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1079 1080config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1081 bool "Reroute for broken boot IRQs" 1082 depends on X86_IO_APIC 1083 ---help--- 1084 This option enables a workaround that fixes a source of 1085 spurious interrupts. This is recommended when threaded 1086 interrupt handling is used on systems where the generation of 1087 superfluous "boot interrupts" cannot be disabled. 1088 1089 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1090 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1091 kernel does during interrupt handling). On chipsets where this 1092 boot IRQ generation cannot be disabled, this workaround keeps 1093 the original IRQ line masked so that only the equivalent "boot 1094 IRQ" is delivered to the CPUs. The workaround also tells the 1095 kernel to set up the IRQ handler on the boot IRQ line. In this 1096 way only one interrupt is delivered to the kernel. Otherwise 1097 the spurious second interrupt may cause the kernel to bring 1098 down (vital) interrupt lines. 1099 1100 Only affects "broken" chipsets. Interrupt sharing may be 1101 increased on these systems. 1102 1103config X86_MCE 1104 bool "Machine Check / overheating reporting" 1105 select GENERIC_ALLOCATOR 1106 default y 1107 ---help--- 1108 Machine Check support allows the processor to notify the 1109 kernel if it detects a problem (e.g. overheating, data corruption). 1110 The action the kernel takes depends on the severity of the problem, 1111 ranging from warning messages to halting the machine. 1112 1113config X86_MCELOG_LEGACY 1114 bool "Support for deprecated /dev/mcelog character device" 1115 depends on X86_MCE 1116 ---help--- 1117 Enable support for /dev/mcelog which is needed by the old mcelog 1118 userspace logging daemon. Consider switching to the new generation 1119 rasdaemon solution. 1120 1121config X86_MCE_INTEL 1122 def_bool y 1123 prompt "Intel MCE features" 1124 depends on X86_MCE && X86_LOCAL_APIC 1125 ---help--- 1126 Additional support for intel specific MCE features such as 1127 the thermal monitor. 1128 1129config X86_MCE_AMD 1130 def_bool y 1131 prompt "AMD MCE features" 1132 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1133 ---help--- 1134 Additional support for AMD specific MCE features such as 1135 the DRAM Error Threshold. 1136 1137config X86_ANCIENT_MCE 1138 bool "Support for old Pentium 5 / WinChip machine checks" 1139 depends on X86_32 && X86_MCE 1140 ---help--- 1141 Include support for machine check handling on old Pentium 5 or WinChip 1142 systems. These typically need to be enabled explicitly on the command 1143 line. 1144 1145config X86_MCE_THRESHOLD 1146 depends on X86_MCE_AMD || X86_MCE_INTEL 1147 def_bool y 1148 1149config X86_MCE_INJECT 1150 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1151 tristate "Machine check injector support" 1152 ---help--- 1153 Provide support for injecting machine checks for testing purposes. 1154 If you don't know what a machine check is and you don't do kernel 1155 QA it is safe to say n. 1156 1157config X86_THERMAL_VECTOR 1158 def_bool y 1159 depends on X86_MCE_INTEL 1160 1161source "arch/x86/events/Kconfig" 1162 1163config X86_LEGACY_VM86 1164 bool "Legacy VM86 support" 1165 depends on X86_32 1166 ---help--- 1167 This option allows user programs to put the CPU into V8086 1168 mode, which is an 80286-era approximation of 16-bit real mode. 1169 1170 Some very old versions of X and/or vbetool require this option 1171 for user mode setting. Similarly, DOSEMU will use it if 1172 available to accelerate real mode DOS programs. However, any 1173 recent version of DOSEMU, X, or vbetool should be fully 1174 functional even without kernel VM86 support, as they will all 1175 fall back to software emulation. Nevertheless, if you are using 1176 a 16-bit DOS program where 16-bit performance matters, vm86 1177 mode might be faster than emulation and you might want to 1178 enable this option. 1179 1180 Note that any app that works on a 64-bit kernel is unlikely to 1181 need this option, as 64-bit kernels don't, and can't, support 1182 V8086 mode. This option is also unrelated to 16-bit protected 1183 mode and is not needed to run most 16-bit programs under Wine. 1184 1185 Enabling this option increases the complexity of the kernel 1186 and slows down exception handling a tiny bit. 1187 1188 If unsure, say N here. 1189 1190config VM86 1191 bool 1192 default X86_LEGACY_VM86 1193 1194config X86_16BIT 1195 bool "Enable support for 16-bit segments" if EXPERT 1196 default y 1197 depends on MODIFY_LDT_SYSCALL 1198 ---help--- 1199 This option is required by programs like Wine to run 16-bit 1200 protected mode legacy code on x86 processors. Disabling 1201 this option saves about 300 bytes on i386, or around 6K text 1202 plus 16K runtime memory on x86-64, 1203 1204config X86_ESPFIX32 1205 def_bool y 1206 depends on X86_16BIT && X86_32 1207 1208config X86_ESPFIX64 1209 def_bool y 1210 depends on X86_16BIT && X86_64 1211 1212config X86_VSYSCALL_EMULATION 1213 bool "Enable vsyscall emulation" if EXPERT 1214 default y 1215 depends on X86_64 1216 ---help--- 1217 This enables emulation of the legacy vsyscall page. Disabling 1218 it is roughly equivalent to booting with vsyscall=none, except 1219 that it will also disable the helpful warning if a program 1220 tries to use a vsyscall. With this option set to N, offending 1221 programs will just segfault, citing addresses of the form 1222 0xffffffffff600?00. 1223 1224 This option is required by many programs built before 2013, and 1225 care should be used even with newer programs if set to N. 1226 1227 Disabling this option saves about 7K of kernel size and 1228 possibly 4K of additional runtime pagetable memory. 1229 1230config X86_IOPL_IOPERM 1231 bool "IOPERM and IOPL Emulation" 1232 default y 1233 ---help--- 1234 This enables the ioperm() and iopl() syscalls which are necessary 1235 for legacy applications. 1236 1237 Legacy IOPL support is an overbroad mechanism which allows user 1238 space aside of accessing all 65536 I/O ports also to disable 1239 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1240 capabilities and permission from potentially active security 1241 modules. 1242 1243 The emulation restricts the functionality of the syscall to 1244 only allowing the full range I/O port access, but prevents the 1245 ability to disable interrupts from user space which would be 1246 granted if the hardware IOPL mechanism would be used. 1247 1248config TOSHIBA 1249 tristate "Toshiba Laptop support" 1250 depends on X86_32 1251 ---help--- 1252 This adds a driver to safely access the System Management Mode of 1253 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1254 not work on models with a Phoenix BIOS. The System Management Mode 1255 is used to set the BIOS and power saving options on Toshiba portables. 1256 1257 For information on utilities to make use of this driver see the 1258 Toshiba Linux utilities web site at: 1259 <http://www.buzzard.org.uk/toshiba/>. 1260 1261 Say Y if you intend to run this kernel on a Toshiba portable. 1262 Say N otherwise. 1263 1264config I8K 1265 tristate "Dell i8k legacy laptop support" 1266 select HWMON 1267 select SENSORS_DELL_SMM 1268 ---help--- 1269 This option enables legacy /proc/i8k userspace interface in hwmon 1270 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1271 temperature and allows controlling fan speeds of Dell laptops via 1272 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1273 it reports also power and hotkey status. For fan speed control is 1274 needed userspace package i8kutils. 1275 1276 Say Y if you intend to run this kernel on old Dell laptops or want to 1277 use userspace package i8kutils. 1278 Say N otherwise. 1279 1280config X86_REBOOTFIXUPS 1281 bool "Enable X86 board specific fixups for reboot" 1282 depends on X86_32 1283 ---help--- 1284 This enables chipset and/or board specific fixups to be done 1285 in order to get reboot to work correctly. This is only needed on 1286 some combinations of hardware and BIOS. The symptom, for which 1287 this config is intended, is when reboot ends with a stalled/hung 1288 system. 1289 1290 Currently, the only fixup is for the Geode machines using 1291 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1292 1293 Say Y if you want to enable the fixup. Currently, it's safe to 1294 enable this option even if you don't need it. 1295 Say N otherwise. 1296 1297config MICROCODE 1298 bool "CPU microcode loading support" 1299 default y 1300 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1301 select FW_LOADER 1302 ---help--- 1303 If you say Y here, you will be able to update the microcode on 1304 Intel and AMD processors. The Intel support is for the IA32 family, 1305 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1306 AMD support is for families 0x10 and later. You will obviously need 1307 the actual microcode binary data itself which is not shipped with 1308 the Linux kernel. 1309 1310 The preferred method to load microcode from a detached initrd is described 1311 in Documentation/x86/microcode.rst. For that you need to enable 1312 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1313 initrd for microcode blobs. 1314 1315 In addition, you can build the microcode into the kernel. For that you 1316 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1317 config option. 1318 1319config MICROCODE_INTEL 1320 bool "Intel microcode loading support" 1321 depends on MICROCODE 1322 default MICROCODE 1323 select FW_LOADER 1324 ---help--- 1325 This options enables microcode patch loading support for Intel 1326 processors. 1327 1328 For the current Intel microcode data package go to 1329 <https://downloadcenter.intel.com> and search for 1330 'Linux Processor Microcode Data File'. 1331 1332config MICROCODE_AMD 1333 bool "AMD microcode loading support" 1334 depends on MICROCODE 1335 select FW_LOADER 1336 ---help--- 1337 If you select this option, microcode patch loading support for AMD 1338 processors will be enabled. 1339 1340config MICROCODE_OLD_INTERFACE 1341 bool "Ancient loading interface (DEPRECATED)" 1342 default n 1343 depends on MICROCODE 1344 ---help--- 1345 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1346 which was used by userspace tools like iucode_tool and microcode.ctl. 1347 It is inadequate because it runs too late to be able to properly 1348 load microcode on a machine and it needs special tools. Instead, you 1349 should've switched to the early loading method with the initrd or 1350 builtin microcode by now: Documentation/x86/microcode.rst 1351 1352config X86_MSR 1353 tristate "/dev/cpu/*/msr - Model-specific register support" 1354 ---help--- 1355 This device gives privileged processes access to the x86 1356 Model-Specific Registers (MSRs). It is a character device with 1357 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1358 MSR accesses are directed to a specific CPU on multi-processor 1359 systems. 1360 1361config X86_CPUID 1362 tristate "/dev/cpu/*/cpuid - CPU information support" 1363 ---help--- 1364 This device gives processes access to the x86 CPUID instruction to 1365 be executed on a specific processor. It is a character device 1366 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1367 /dev/cpu/31/cpuid. 1368 1369choice 1370 prompt "High Memory Support" 1371 default HIGHMEM4G 1372 depends on X86_32 1373 1374config NOHIGHMEM 1375 bool "off" 1376 ---help--- 1377 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1378 However, the address space of 32-bit x86 processors is only 4 1379 Gigabytes large. That means that, if you have a large amount of 1380 physical memory, not all of it can be "permanently mapped" by the 1381 kernel. The physical memory that's not permanently mapped is called 1382 "high memory". 1383 1384 If you are compiling a kernel which will never run on a machine with 1385 more than 1 Gigabyte total physical RAM, answer "off" here (default 1386 choice and suitable for most users). This will result in a "3GB/1GB" 1387 split: 3GB are mapped so that each process sees a 3GB virtual memory 1388 space and the remaining part of the 4GB virtual memory space is used 1389 by the kernel to permanently map as much physical memory as 1390 possible. 1391 1392 If the machine has between 1 and 4 Gigabytes physical RAM, then 1393 answer "4GB" here. 1394 1395 If more than 4 Gigabytes is used then answer "64GB" here. This 1396 selection turns Intel PAE (Physical Address Extension) mode on. 1397 PAE implements 3-level paging on IA32 processors. PAE is fully 1398 supported by Linux, PAE mode is implemented on all recent Intel 1399 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1400 then the kernel will not boot on CPUs that don't support PAE! 1401 1402 The actual amount of total physical memory will either be 1403 auto detected or can be forced by using a kernel command line option 1404 such as "mem=256M". (Try "man bootparam" or see the documentation of 1405 your boot loader (lilo or loadlin) about how to pass options to the 1406 kernel at boot time.) 1407 1408 If unsure, say "off". 1409 1410config HIGHMEM4G 1411 bool "4GB" 1412 ---help--- 1413 Select this if you have a 32-bit processor and between 1 and 4 1414 gigabytes of physical RAM. 1415 1416config HIGHMEM64G 1417 bool "64GB" 1418 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1419 select X86_PAE 1420 ---help--- 1421 Select this if you have a 32-bit processor and more than 4 1422 gigabytes of physical RAM. 1423 1424endchoice 1425 1426choice 1427 prompt "Memory split" if EXPERT 1428 default VMSPLIT_3G 1429 depends on X86_32 1430 ---help--- 1431 Select the desired split between kernel and user memory. 1432 1433 If the address range available to the kernel is less than the 1434 physical memory installed, the remaining memory will be available 1435 as "high memory". Accessing high memory is a little more costly 1436 than low memory, as it needs to be mapped into the kernel first. 1437 Note that increasing the kernel address space limits the range 1438 available to user programs, making the address space there 1439 tighter. Selecting anything other than the default 3G/1G split 1440 will also likely make your kernel incompatible with binary-only 1441 kernel modules. 1442 1443 If you are not absolutely sure what you are doing, leave this 1444 option alone! 1445 1446 config VMSPLIT_3G 1447 bool "3G/1G user/kernel split" 1448 config VMSPLIT_3G_OPT 1449 depends on !X86_PAE 1450 bool "3G/1G user/kernel split (for full 1G low memory)" 1451 config VMSPLIT_2G 1452 bool "2G/2G user/kernel split" 1453 config VMSPLIT_2G_OPT 1454 depends on !X86_PAE 1455 bool "2G/2G user/kernel split (for full 2G low memory)" 1456 config VMSPLIT_1G 1457 bool "1G/3G user/kernel split" 1458endchoice 1459 1460config PAGE_OFFSET 1461 hex 1462 default 0xB0000000 if VMSPLIT_3G_OPT 1463 default 0x80000000 if VMSPLIT_2G 1464 default 0x78000000 if VMSPLIT_2G_OPT 1465 default 0x40000000 if VMSPLIT_1G 1466 default 0xC0000000 1467 depends on X86_32 1468 1469config HIGHMEM 1470 def_bool y 1471 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1472 1473config X86_PAE 1474 bool "PAE (Physical Address Extension) Support" 1475 depends on X86_32 && !HIGHMEM4G 1476 select PHYS_ADDR_T_64BIT 1477 select SWIOTLB 1478 ---help--- 1479 PAE is required for NX support, and furthermore enables 1480 larger swapspace support for non-overcommit purposes. It 1481 has the cost of more pagetable lookup overhead, and also 1482 consumes more pagetable space per process. 1483 1484config X86_5LEVEL 1485 bool "Enable 5-level page tables support" 1486 default y 1487 select DYNAMIC_MEMORY_LAYOUT 1488 select SPARSEMEM_VMEMMAP 1489 depends on X86_64 1490 ---help--- 1491 5-level paging enables access to larger address space: 1492 upto 128 PiB of virtual address space and 4 PiB of 1493 physical address space. 1494 1495 It will be supported by future Intel CPUs. 1496 1497 A kernel with the option enabled can be booted on machines that 1498 support 4- or 5-level paging. 1499 1500 See Documentation/x86/x86_64/5level-paging.rst for more 1501 information. 1502 1503 Say N if unsure. 1504 1505config X86_DIRECT_GBPAGES 1506 def_bool y 1507 depends on X86_64 1508 ---help--- 1509 Certain kernel features effectively disable kernel 1510 linear 1 GB mappings (even if the CPU otherwise 1511 supports them), so don't confuse the user by printing 1512 that we have them enabled. 1513 1514config X86_CPA_STATISTICS 1515 bool "Enable statistic for Change Page Attribute" 1516 depends on DEBUG_FS 1517 ---help--- 1518 Expose statistics about the Change Page Attribute mechanism, which 1519 helps to determine the effectiveness of preserving large and huge 1520 page mappings when mapping protections are changed. 1521 1522config AMD_MEM_ENCRYPT 1523 bool "AMD Secure Memory Encryption (SME) support" 1524 depends on X86_64 && CPU_SUP_AMD 1525 select DYNAMIC_PHYSICAL_MASK 1526 select ARCH_USE_MEMREMAP_PROT 1527 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1528 ---help--- 1529 Say yes to enable support for the encryption of system memory. 1530 This requires an AMD processor that supports Secure Memory 1531 Encryption (SME). 1532 1533config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1534 bool "Activate AMD Secure Memory Encryption (SME) by default" 1535 default y 1536 depends on AMD_MEM_ENCRYPT 1537 ---help--- 1538 Say yes to have system memory encrypted by default if running on 1539 an AMD processor that supports Secure Memory Encryption (SME). 1540 1541 If set to Y, then the encryption of system memory can be 1542 deactivated with the mem_encrypt=off command line option. 1543 1544 If set to N, then the encryption of system memory can be 1545 activated with the mem_encrypt=on command line option. 1546 1547# Common NUMA Features 1548config NUMA 1549 bool "NUMA Memory Allocation and Scheduler Support" 1550 depends on SMP 1551 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1552 default y if X86_BIGSMP 1553 ---help--- 1554 Enable NUMA (Non-Uniform Memory Access) support. 1555 1556 The kernel will try to allocate memory used by a CPU on the 1557 local memory controller of the CPU and add some more 1558 NUMA awareness to the kernel. 1559 1560 For 64-bit this is recommended if the system is Intel Core i7 1561 (or later), AMD Opteron, or EM64T NUMA. 1562 1563 For 32-bit this is only needed if you boot a 32-bit 1564 kernel on a 64-bit NUMA platform. 1565 1566 Otherwise, you should say N. 1567 1568config AMD_NUMA 1569 def_bool y 1570 prompt "Old style AMD Opteron NUMA detection" 1571 depends on X86_64 && NUMA && PCI 1572 ---help--- 1573 Enable AMD NUMA node topology detection. You should say Y here if 1574 you have a multi processor AMD system. This uses an old method to 1575 read the NUMA configuration directly from the builtin Northbridge 1576 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1577 which also takes priority if both are compiled in. 1578 1579config X86_64_ACPI_NUMA 1580 def_bool y 1581 prompt "ACPI NUMA detection" 1582 depends on X86_64 && NUMA && ACPI && PCI 1583 select ACPI_NUMA 1584 ---help--- 1585 Enable ACPI SRAT based node topology detection. 1586 1587# Some NUMA nodes have memory ranges that span 1588# other nodes. Even though a pfn is valid and 1589# between a node's start and end pfns, it may not 1590# reside on that node. See memmap_init_zone() 1591# for details. 1592config NODES_SPAN_OTHER_NODES 1593 def_bool y 1594 depends on X86_64_ACPI_NUMA 1595 1596config NUMA_EMU 1597 bool "NUMA emulation" 1598 depends on NUMA 1599 ---help--- 1600 Enable NUMA emulation. A flat machine will be split 1601 into virtual nodes when booted with "numa=fake=N", where N is the 1602 number of nodes. This is only useful for debugging. 1603 1604config NODES_SHIFT 1605 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1606 range 1 10 1607 default "10" if MAXSMP 1608 default "6" if X86_64 1609 default "3" 1610 depends on NEED_MULTIPLE_NODES 1611 ---help--- 1612 Specify the maximum number of NUMA Nodes available on the target 1613 system. Increases memory reserved to accommodate various tables. 1614 1615config ARCH_HAVE_MEMORY_PRESENT 1616 def_bool y 1617 depends on X86_32 && DISCONTIGMEM 1618 1619config ARCH_FLATMEM_ENABLE 1620 def_bool y 1621 depends on X86_32 && !NUMA 1622 1623config ARCH_DISCONTIGMEM_ENABLE 1624 def_bool n 1625 depends on NUMA && X86_32 1626 depends on BROKEN 1627 1628config ARCH_SPARSEMEM_ENABLE 1629 def_bool y 1630 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1631 select SPARSEMEM_STATIC if X86_32 1632 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1633 1634config ARCH_SPARSEMEM_DEFAULT 1635 def_bool X86_64 || (NUMA && X86_32) 1636 1637config ARCH_SELECT_MEMORY_MODEL 1638 def_bool y 1639 depends on ARCH_SPARSEMEM_ENABLE 1640 1641config ARCH_MEMORY_PROBE 1642 bool "Enable sysfs memory/probe interface" 1643 depends on X86_64 && MEMORY_HOTPLUG 1644 help 1645 This option enables a sysfs memory/probe interface for testing. 1646 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1647 If you are unsure how to answer this question, answer N. 1648 1649config ARCH_PROC_KCORE_TEXT 1650 def_bool y 1651 depends on X86_64 && PROC_KCORE 1652 1653config ILLEGAL_POINTER_VALUE 1654 hex 1655 default 0 if X86_32 1656 default 0xdead000000000000 if X86_64 1657 1658config X86_PMEM_LEGACY_DEVICE 1659 bool 1660 1661config X86_PMEM_LEGACY 1662 tristate "Support non-standard NVDIMMs and ADR protected memory" 1663 depends on PHYS_ADDR_T_64BIT 1664 depends on BLK_DEV 1665 select X86_PMEM_LEGACY_DEVICE 1666 select LIBNVDIMM 1667 help 1668 Treat memory marked using the non-standard e820 type of 12 as used 1669 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1670 The kernel will offer these regions to the 'pmem' driver so 1671 they can be used for persistent storage. 1672 1673 Say Y if unsure. 1674 1675config HIGHPTE 1676 bool "Allocate 3rd-level pagetables from highmem" 1677 depends on HIGHMEM 1678 ---help--- 1679 The VM uses one page table entry for each page of physical memory. 1680 For systems with a lot of RAM, this can be wasteful of precious 1681 low memory. Setting this option will put user-space page table 1682 entries in high memory. 1683 1684config X86_CHECK_BIOS_CORRUPTION 1685 bool "Check for low memory corruption" 1686 ---help--- 1687 Periodically check for memory corruption in low memory, which 1688 is suspected to be caused by BIOS. Even when enabled in the 1689 configuration, it is disabled at runtime. Enable it by 1690 setting "memory_corruption_check=1" on the kernel command 1691 line. By default it scans the low 64k of memory every 60 1692 seconds; see the memory_corruption_check_size and 1693 memory_corruption_check_period parameters in 1694 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1695 1696 When enabled with the default parameters, this option has 1697 almost no overhead, as it reserves a relatively small amount 1698 of memory and scans it infrequently. It both detects corruption 1699 and prevents it from affecting the running system. 1700 1701 It is, however, intended as a diagnostic tool; if repeatable 1702 BIOS-originated corruption always affects the same memory, 1703 you can use memmap= to prevent the kernel from using that 1704 memory. 1705 1706config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1707 bool "Set the default setting of memory_corruption_check" 1708 depends on X86_CHECK_BIOS_CORRUPTION 1709 default y 1710 ---help--- 1711 Set whether the default state of memory_corruption_check is 1712 on or off. 1713 1714config X86_RESERVE_LOW 1715 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1716 default 64 1717 range 4 640 1718 ---help--- 1719 Specify the amount of low memory to reserve for the BIOS. 1720 1721 The first page contains BIOS data structures that the kernel 1722 must not use, so that page must always be reserved. 1723 1724 By default we reserve the first 64K of physical RAM, as a 1725 number of BIOSes are known to corrupt that memory range 1726 during events such as suspend/resume or monitor cable 1727 insertion, so it must not be used by the kernel. 1728 1729 You can set this to 4 if you are absolutely sure that you 1730 trust the BIOS to get all its memory reservations and usages 1731 right. If you know your BIOS have problems beyond the 1732 default 64K area, you can set this to 640 to avoid using the 1733 entire low memory range. 1734 1735 If you have doubts about the BIOS (e.g. suspend/resume does 1736 not work or there's kernel crashes after certain hardware 1737 hotplug events) then you might want to enable 1738 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1739 typical corruption patterns. 1740 1741 Leave this to the default value of 64 if you are unsure. 1742 1743config MATH_EMULATION 1744 bool 1745 depends on MODIFY_LDT_SYSCALL 1746 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1747 ---help--- 1748 Linux can emulate a math coprocessor (used for floating point 1749 operations) if you don't have one. 486DX and Pentium processors have 1750 a math coprocessor built in, 486SX and 386 do not, unless you added 1751 a 487DX or 387, respectively. (The messages during boot time can 1752 give you some hints here ["man dmesg"].) Everyone needs either a 1753 coprocessor or this emulation. 1754 1755 If you don't have a math coprocessor, you need to say Y here; if you 1756 say Y here even though you have a coprocessor, the coprocessor will 1757 be used nevertheless. (This behavior can be changed with the kernel 1758 command line option "no387", which comes handy if your coprocessor 1759 is broken. Try "man bootparam" or see the documentation of your boot 1760 loader (lilo or loadlin) about how to pass options to the kernel at 1761 boot time.) This means that it is a good idea to say Y here if you 1762 intend to use this kernel on different machines. 1763 1764 More information about the internals of the Linux math coprocessor 1765 emulation can be found in <file:arch/x86/math-emu/README>. 1766 1767 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1768 kernel, it won't hurt. 1769 1770config MTRR 1771 def_bool y 1772 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1773 ---help--- 1774 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1775 the Memory Type Range Registers (MTRRs) may be used to control 1776 processor access to memory ranges. This is most useful if you have 1777 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1778 allows bus write transfers to be combined into a larger transfer 1779 before bursting over the PCI/AGP bus. This can increase performance 1780 of image write operations 2.5 times or more. Saying Y here creates a 1781 /proc/mtrr file which may be used to manipulate your processor's 1782 MTRRs. Typically the X server should use this. 1783 1784 This code has a reasonably generic interface so that similar 1785 control registers on other processors can be easily supported 1786 as well: 1787 1788 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1789 Registers (ARRs) which provide a similar functionality to MTRRs. For 1790 these, the ARRs are used to emulate the MTRRs. 1791 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1792 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1793 write-combining. All of these processors are supported by this code 1794 and it makes sense to say Y here if you have one of them. 1795 1796 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1797 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1798 can lead to all sorts of problems, so it's good to say Y here. 1799 1800 You can safely say Y even if your machine doesn't have MTRRs, you'll 1801 just add about 9 KB to your kernel. 1802 1803 See <file:Documentation/x86/mtrr.rst> for more information. 1804 1805config MTRR_SANITIZER 1806 def_bool y 1807 prompt "MTRR cleanup support" 1808 depends on MTRR 1809 ---help--- 1810 Convert MTRR layout from continuous to discrete, so X drivers can 1811 add writeback entries. 1812 1813 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1814 The largest mtrr entry size for a continuous block can be set with 1815 mtrr_chunk_size. 1816 1817 If unsure, say Y. 1818 1819config MTRR_SANITIZER_ENABLE_DEFAULT 1820 int "MTRR cleanup enable value (0-1)" 1821 range 0 1 1822 default "0" 1823 depends on MTRR_SANITIZER 1824 ---help--- 1825 Enable mtrr cleanup default value 1826 1827config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1828 int "MTRR cleanup spare reg num (0-7)" 1829 range 0 7 1830 default "1" 1831 depends on MTRR_SANITIZER 1832 ---help--- 1833 mtrr cleanup spare entries default, it can be changed via 1834 mtrr_spare_reg_nr=N on the kernel command line. 1835 1836config X86_PAT 1837 def_bool y 1838 prompt "x86 PAT support" if EXPERT 1839 depends on MTRR 1840 ---help--- 1841 Use PAT attributes to setup page level cache control. 1842 1843 PATs are the modern equivalents of MTRRs and are much more 1844 flexible than MTRRs. 1845 1846 Say N here if you see bootup problems (boot crash, boot hang, 1847 spontaneous reboots) or a non-working video driver. 1848 1849 If unsure, say Y. 1850 1851config ARCH_USES_PG_UNCACHED 1852 def_bool y 1853 depends on X86_PAT 1854 1855config ARCH_RANDOM 1856 def_bool y 1857 prompt "x86 architectural random number generator" if EXPERT 1858 ---help--- 1859 Enable the x86 architectural RDRAND instruction 1860 (Intel Bull Mountain technology) to generate random numbers. 1861 If supported, this is a high bandwidth, cryptographically 1862 secure hardware random number generator. 1863 1864config X86_SMAP 1865 def_bool y 1866 prompt "Supervisor Mode Access Prevention" if EXPERT 1867 ---help--- 1868 Supervisor Mode Access Prevention (SMAP) is a security 1869 feature in newer Intel processors. There is a small 1870 performance cost if this enabled and turned on; there is 1871 also a small increase in the kernel size if this is enabled. 1872 1873 If unsure, say Y. 1874 1875config X86_UMIP 1876 def_bool y 1877 depends on CPU_SUP_INTEL || CPU_SUP_AMD 1878 prompt "User Mode Instruction Prevention" if EXPERT 1879 ---help--- 1880 User Mode Instruction Prevention (UMIP) is a security feature in 1881 some x86 processors. If enabled, a general protection fault is 1882 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1883 executed in user mode. These instructions unnecessarily expose 1884 information about the hardware state. 1885 1886 The vast majority of applications do not use these instructions. 1887 For the very few that do, software emulation is provided in 1888 specific cases in protected and virtual-8086 modes. Emulated 1889 results are dummy. 1890 1891config X86_INTEL_MEMORY_PROTECTION_KEYS 1892 prompt "Intel Memory Protection Keys" 1893 def_bool y 1894 # Note: only available in 64-bit mode 1895 depends on CPU_SUP_INTEL && X86_64 1896 select ARCH_USES_HIGH_VMA_FLAGS 1897 select ARCH_HAS_PKEYS 1898 ---help--- 1899 Memory Protection Keys provides a mechanism for enforcing 1900 page-based protections, but without requiring modification of the 1901 page tables when an application changes protection domains. 1902 1903 For details, see Documentation/core-api/protection-keys.rst 1904 1905 If unsure, say y. 1906 1907choice 1908 prompt "TSX enable mode" 1909 depends on CPU_SUP_INTEL 1910 default X86_INTEL_TSX_MODE_OFF 1911 help 1912 Intel's TSX (Transactional Synchronization Extensions) feature 1913 allows to optimize locking protocols through lock elision which 1914 can lead to a noticeable performance boost. 1915 1916 On the other hand it has been shown that TSX can be exploited 1917 to form side channel attacks (e.g. TAA) and chances are there 1918 will be more of those attacks discovered in the future. 1919 1920 Therefore TSX is not enabled by default (aka tsx=off). An admin 1921 might override this decision by tsx=on the command line parameter. 1922 Even with TSX enabled, the kernel will attempt to enable the best 1923 possible TAA mitigation setting depending on the microcode available 1924 for the particular machine. 1925 1926 This option allows to set the default tsx mode between tsx=on, =off 1927 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1928 details. 1929 1930 Say off if not sure, auto if TSX is in use but it should be used on safe 1931 platforms or on if TSX is in use and the security aspect of tsx is not 1932 relevant. 1933 1934config X86_INTEL_TSX_MODE_OFF 1935 bool "off" 1936 help 1937 TSX is disabled if possible - equals to tsx=off command line parameter. 1938 1939config X86_INTEL_TSX_MODE_ON 1940 bool "on" 1941 help 1942 TSX is always enabled on TSX capable HW - equals the tsx=on command 1943 line parameter. 1944 1945config X86_INTEL_TSX_MODE_AUTO 1946 bool "auto" 1947 help 1948 TSX is enabled on TSX capable HW that is believed to be safe against 1949 side channel attacks- equals the tsx=auto command line parameter. 1950endchoice 1951 1952config EFI 1953 bool "EFI runtime service support" 1954 depends on ACPI 1955 select UCS2_STRING 1956 select EFI_RUNTIME_WRAPPERS 1957 ---help--- 1958 This enables the kernel to use EFI runtime services that are 1959 available (such as the EFI variable services). 1960 1961 This option is only useful on systems that have EFI firmware. 1962 In addition, you should use the latest ELILO loader available 1963 at <http://elilo.sourceforge.net> in order to take advantage 1964 of EFI runtime services. However, even with this option, the 1965 resultant kernel should continue to boot on existing non-EFI 1966 platforms. 1967 1968config EFI_STUB 1969 bool "EFI stub support" 1970 depends on EFI && !X86_USE_3DNOW 1971 depends on $(cc-option,-mabi=ms) || X86_32 1972 select RELOCATABLE 1973 ---help--- 1974 This kernel feature allows a bzImage to be loaded directly 1975 by EFI firmware without the use of a bootloader. 1976 1977 See Documentation/admin-guide/efi-stub.rst for more information. 1978 1979config EFI_MIXED 1980 bool "EFI mixed-mode support" 1981 depends on EFI_STUB && X86_64 1982 ---help--- 1983 Enabling this feature allows a 64-bit kernel to be booted 1984 on a 32-bit firmware, provided that your CPU supports 64-bit 1985 mode. 1986 1987 Note that it is not possible to boot a mixed-mode enabled 1988 kernel via the EFI boot stub - a bootloader that supports 1989 the EFI handover protocol must be used. 1990 1991 If unsure, say N. 1992 1993config SECCOMP 1994 def_bool y 1995 prompt "Enable seccomp to safely compute untrusted bytecode" 1996 ---help--- 1997 This kernel feature is useful for number crunching applications 1998 that may need to compute untrusted bytecode during their 1999 execution. By using pipes or other transports made available to 2000 the process as file descriptors supporting the read/write 2001 syscalls, it's possible to isolate those applications in 2002 their own address space using seccomp. Once seccomp is 2003 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 2004 and the task is only allowed to execute a few safe syscalls 2005 defined by each seccomp mode. 2006 2007 If unsure, say Y. Only embedded should say N here. 2008 2009source "kernel/Kconfig.hz" 2010 2011config KEXEC 2012 bool "kexec system call" 2013 select KEXEC_CORE 2014 ---help--- 2015 kexec is a system call that implements the ability to shutdown your 2016 current kernel, and to start another kernel. It is like a reboot 2017 but it is independent of the system firmware. And like a reboot 2018 you can start any kernel with it, not just Linux. 2019 2020 The name comes from the similarity to the exec system call. 2021 2022 It is an ongoing process to be certain the hardware in a machine 2023 is properly shutdown, so do not be surprised if this code does not 2024 initially work for you. As of this writing the exact hardware 2025 interface is strongly in flux, so no good recommendation can be 2026 made. 2027 2028config KEXEC_FILE 2029 bool "kexec file based system call" 2030 select KEXEC_CORE 2031 select BUILD_BIN2C 2032 depends on X86_64 2033 depends on CRYPTO=y 2034 depends on CRYPTO_SHA256=y 2035 ---help--- 2036 This is new version of kexec system call. This system call is 2037 file based and takes file descriptors as system call argument 2038 for kernel and initramfs as opposed to list of segments as 2039 accepted by previous system call. 2040 2041config ARCH_HAS_KEXEC_PURGATORY 2042 def_bool KEXEC_FILE 2043 2044config KEXEC_SIG 2045 bool "Verify kernel signature during kexec_file_load() syscall" 2046 depends on KEXEC_FILE 2047 ---help--- 2048 2049 This option makes the kexec_file_load() syscall check for a valid 2050 signature of the kernel image. The image can still be loaded without 2051 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2052 there's a signature that we can check, then it must be valid. 2053 2054 In addition to this option, you need to enable signature 2055 verification for the corresponding kernel image type being 2056 loaded in order for this to work. 2057 2058config KEXEC_SIG_FORCE 2059 bool "Require a valid signature in kexec_file_load() syscall" 2060 depends on KEXEC_SIG 2061 ---help--- 2062 This option makes kernel signature verification mandatory for 2063 the kexec_file_load() syscall. 2064 2065config KEXEC_BZIMAGE_VERIFY_SIG 2066 bool "Enable bzImage signature verification support" 2067 depends on KEXEC_SIG 2068 depends on SIGNED_PE_FILE_VERIFICATION 2069 select SYSTEM_TRUSTED_KEYRING 2070 ---help--- 2071 Enable bzImage signature verification support. 2072 2073config CRASH_DUMP 2074 bool "kernel crash dumps" 2075 depends on X86_64 || (X86_32 && HIGHMEM) 2076 ---help--- 2077 Generate crash dump after being started by kexec. 2078 This should be normally only set in special crash dump kernels 2079 which are loaded in the main kernel with kexec-tools into 2080 a specially reserved region and then later executed after 2081 a crash by kdump/kexec. The crash dump kernel must be compiled 2082 to a memory address not used by the main kernel or BIOS using 2083 PHYSICAL_START, or it must be built as a relocatable image 2084 (CONFIG_RELOCATABLE=y). 2085 For more details see Documentation/admin-guide/kdump/kdump.rst 2086 2087config KEXEC_JUMP 2088 bool "kexec jump" 2089 depends on KEXEC && HIBERNATION 2090 ---help--- 2091 Jump between original kernel and kexeced kernel and invoke 2092 code in physical address mode via KEXEC 2093 2094config PHYSICAL_START 2095 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2096 default "0x1000000" 2097 ---help--- 2098 This gives the physical address where the kernel is loaded. 2099 2100 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2101 bzImage will decompress itself to above physical address and 2102 run from there. Otherwise, bzImage will run from the address where 2103 it has been loaded by the boot loader and will ignore above physical 2104 address. 2105 2106 In normal kdump cases one does not have to set/change this option 2107 as now bzImage can be compiled as a completely relocatable image 2108 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2109 address. This option is mainly useful for the folks who don't want 2110 to use a bzImage for capturing the crash dump and want to use a 2111 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2112 to be specifically compiled to run from a specific memory area 2113 (normally a reserved region) and this option comes handy. 2114 2115 So if you are using bzImage for capturing the crash dump, 2116 leave the value here unchanged to 0x1000000 and set 2117 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2118 for capturing the crash dump change this value to start of 2119 the reserved region. In other words, it can be set based on 2120 the "X" value as specified in the "crashkernel=YM@XM" 2121 command line boot parameter passed to the panic-ed 2122 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2123 for more details about crash dumps. 2124 2125 Usage of bzImage for capturing the crash dump is recommended as 2126 one does not have to build two kernels. Same kernel can be used 2127 as production kernel and capture kernel. Above option should have 2128 gone away after relocatable bzImage support is introduced. But it 2129 is present because there are users out there who continue to use 2130 vmlinux for dump capture. This option should go away down the 2131 line. 2132 2133 Don't change this unless you know what you are doing. 2134 2135config RELOCATABLE 2136 bool "Build a relocatable kernel" 2137 default y 2138 ---help--- 2139 This builds a kernel image that retains relocation information 2140 so it can be loaded someplace besides the default 1MB. 2141 The relocations tend to make the kernel binary about 10% larger, 2142 but are discarded at runtime. 2143 2144 One use is for the kexec on panic case where the recovery kernel 2145 must live at a different physical address than the primary 2146 kernel. 2147 2148 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2149 it has been loaded at and the compile time physical address 2150 (CONFIG_PHYSICAL_START) is used as the minimum location. 2151 2152config RANDOMIZE_BASE 2153 bool "Randomize the address of the kernel image (KASLR)" 2154 depends on RELOCATABLE 2155 default y 2156 ---help--- 2157 In support of Kernel Address Space Layout Randomization (KASLR), 2158 this randomizes the physical address at which the kernel image 2159 is decompressed and the virtual address where the kernel 2160 image is mapped, as a security feature that deters exploit 2161 attempts relying on knowledge of the location of kernel 2162 code internals. 2163 2164 On 64-bit, the kernel physical and virtual addresses are 2165 randomized separately. The physical address will be anywhere 2166 between 16MB and the top of physical memory (up to 64TB). The 2167 virtual address will be randomized from 16MB up to 1GB (9 bits 2168 of entropy). Note that this also reduces the memory space 2169 available to kernel modules from 1.5GB to 1GB. 2170 2171 On 32-bit, the kernel physical and virtual addresses are 2172 randomized together. They will be randomized from 16MB up to 2173 512MB (8 bits of entropy). 2174 2175 Entropy is generated using the RDRAND instruction if it is 2176 supported. If RDTSC is supported, its value is mixed into 2177 the entropy pool as well. If neither RDRAND nor RDTSC are 2178 supported, then entropy is read from the i8254 timer. The 2179 usable entropy is limited by the kernel being built using 2180 2GB addressing, and that PHYSICAL_ALIGN must be at a 2181 minimum of 2MB. As a result, only 10 bits of entropy are 2182 theoretically possible, but the implementations are further 2183 limited due to memory layouts. 2184 2185 If unsure, say Y. 2186 2187# Relocation on x86 needs some additional build support 2188config X86_NEED_RELOCS 2189 def_bool y 2190 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2191 2192config PHYSICAL_ALIGN 2193 hex "Alignment value to which kernel should be aligned" 2194 default "0x200000" 2195 range 0x2000 0x1000000 if X86_32 2196 range 0x200000 0x1000000 if X86_64 2197 ---help--- 2198 This value puts the alignment restrictions on physical address 2199 where kernel is loaded and run from. Kernel is compiled for an 2200 address which meets above alignment restriction. 2201 2202 If bootloader loads the kernel at a non-aligned address and 2203 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2204 address aligned to above value and run from there. 2205 2206 If bootloader loads the kernel at a non-aligned address and 2207 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2208 load address and decompress itself to the address it has been 2209 compiled for and run from there. The address for which kernel is 2210 compiled already meets above alignment restrictions. Hence the 2211 end result is that kernel runs from a physical address meeting 2212 above alignment restrictions. 2213 2214 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2215 this value must be a multiple of 0x200000. 2216 2217 Don't change this unless you know what you are doing. 2218 2219config DYNAMIC_MEMORY_LAYOUT 2220 bool 2221 ---help--- 2222 This option makes base addresses of vmalloc and vmemmap as well as 2223 __PAGE_OFFSET movable during boot. 2224 2225config RANDOMIZE_MEMORY 2226 bool "Randomize the kernel memory sections" 2227 depends on X86_64 2228 depends on RANDOMIZE_BASE 2229 select DYNAMIC_MEMORY_LAYOUT 2230 default RANDOMIZE_BASE 2231 ---help--- 2232 Randomizes the base virtual address of kernel memory sections 2233 (physical memory mapping, vmalloc & vmemmap). This security feature 2234 makes exploits relying on predictable memory locations less reliable. 2235 2236 The order of allocations remains unchanged. Entropy is generated in 2237 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2238 configuration have in average 30,000 different possible virtual 2239 addresses for each memory section. 2240 2241 If unsure, say Y. 2242 2243config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2244 hex "Physical memory mapping padding" if EXPERT 2245 depends on RANDOMIZE_MEMORY 2246 default "0xa" if MEMORY_HOTPLUG 2247 default "0x0" 2248 range 0x1 0x40 if MEMORY_HOTPLUG 2249 range 0x0 0x40 2250 ---help--- 2251 Define the padding in terabytes added to the existing physical 2252 memory size during kernel memory randomization. It is useful 2253 for memory hotplug support but reduces the entropy available for 2254 address randomization. 2255 2256 If unsure, leave at the default value. 2257 2258config HOTPLUG_CPU 2259 def_bool y 2260 depends on SMP 2261 2262config BOOTPARAM_HOTPLUG_CPU0 2263 bool "Set default setting of cpu0_hotpluggable" 2264 depends on HOTPLUG_CPU 2265 ---help--- 2266 Set whether default state of cpu0_hotpluggable is on or off. 2267 2268 Say Y here to enable CPU0 hotplug by default. If this switch 2269 is turned on, there is no need to give cpu0_hotplug kernel 2270 parameter and the CPU0 hotplug feature is enabled by default. 2271 2272 Please note: there are two known CPU0 dependencies if you want 2273 to enable the CPU0 hotplug feature either by this switch or by 2274 cpu0_hotplug kernel parameter. 2275 2276 First, resume from hibernate or suspend always starts from CPU0. 2277 So hibernate and suspend are prevented if CPU0 is offline. 2278 2279 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2280 offline if any interrupt can not migrate out of CPU0. There may 2281 be other CPU0 dependencies. 2282 2283 Please make sure the dependencies are under your control before 2284 you enable this feature. 2285 2286 Say N if you don't want to enable CPU0 hotplug feature by default. 2287 You still can enable the CPU0 hotplug feature at boot by kernel 2288 parameter cpu0_hotplug. 2289 2290config DEBUG_HOTPLUG_CPU0 2291 def_bool n 2292 prompt "Debug CPU0 hotplug" 2293 depends on HOTPLUG_CPU 2294 ---help--- 2295 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2296 soon as possible and boots up userspace with CPU0 offlined. User 2297 can online CPU0 back after boot time. 2298 2299 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2300 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2301 compilation or giving cpu0_hotplug kernel parameter at boot. 2302 2303 If unsure, say N. 2304 2305config COMPAT_VDSO 2306 def_bool n 2307 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2308 depends on COMPAT_32 2309 ---help--- 2310 Certain buggy versions of glibc will crash if they are 2311 presented with a 32-bit vDSO that is not mapped at the address 2312 indicated in its segment table. 2313 2314 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2315 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2316 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2317 the only released version with the bug, but OpenSUSE 9 2318 contains a buggy "glibc 2.3.2". 2319 2320 The symptom of the bug is that everything crashes on startup, saying: 2321 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2322 2323 Saying Y here changes the default value of the vdso32 boot 2324 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2325 This works around the glibc bug but hurts performance. 2326 2327 If unsure, say N: if you are compiling your own kernel, you 2328 are unlikely to be using a buggy version of glibc. 2329 2330choice 2331 prompt "vsyscall table for legacy applications" 2332 depends on X86_64 2333 default LEGACY_VSYSCALL_XONLY 2334 help 2335 Legacy user code that does not know how to find the vDSO expects 2336 to be able to issue three syscalls by calling fixed addresses in 2337 kernel space. Since this location is not randomized with ASLR, 2338 it can be used to assist security vulnerability exploitation. 2339 2340 This setting can be changed at boot time via the kernel command 2341 line parameter vsyscall=[emulate|xonly|none]. 2342 2343 On a system with recent enough glibc (2.14 or newer) and no 2344 static binaries, you can say None without a performance penalty 2345 to improve security. 2346 2347 If unsure, select "Emulate execution only". 2348 2349 config LEGACY_VSYSCALL_EMULATE 2350 bool "Full emulation" 2351 help 2352 The kernel traps and emulates calls into the fixed vsyscall 2353 address mapping. This makes the mapping non-executable, but 2354 it still contains readable known contents, which could be 2355 used in certain rare security vulnerability exploits. This 2356 configuration is recommended when using legacy userspace 2357 that still uses vsyscalls along with legacy binary 2358 instrumentation tools that require code to be readable. 2359 2360 An example of this type of legacy userspace is running 2361 Pin on an old binary that still uses vsyscalls. 2362 2363 config LEGACY_VSYSCALL_XONLY 2364 bool "Emulate execution only" 2365 help 2366 The kernel traps and emulates calls into the fixed vsyscall 2367 address mapping and does not allow reads. This 2368 configuration is recommended when userspace might use the 2369 legacy vsyscall area but support for legacy binary 2370 instrumentation of legacy code is not needed. It mitigates 2371 certain uses of the vsyscall area as an ASLR-bypassing 2372 buffer. 2373 2374 config LEGACY_VSYSCALL_NONE 2375 bool "None" 2376 help 2377 There will be no vsyscall mapping at all. This will 2378 eliminate any risk of ASLR bypass due to the vsyscall 2379 fixed address mapping. Attempts to use the vsyscalls 2380 will be reported to dmesg, so that either old or 2381 malicious userspace programs can be identified. 2382 2383endchoice 2384 2385config CMDLINE_BOOL 2386 bool "Built-in kernel command line" 2387 ---help--- 2388 Allow for specifying boot arguments to the kernel at 2389 build time. On some systems (e.g. embedded ones), it is 2390 necessary or convenient to provide some or all of the 2391 kernel boot arguments with the kernel itself (that is, 2392 to not rely on the boot loader to provide them.) 2393 2394 To compile command line arguments into the kernel, 2395 set this option to 'Y', then fill in the 2396 boot arguments in CONFIG_CMDLINE. 2397 2398 Systems with fully functional boot loaders (i.e. non-embedded) 2399 should leave this option set to 'N'. 2400 2401config CMDLINE 2402 string "Built-in kernel command string" 2403 depends on CMDLINE_BOOL 2404 default "" 2405 ---help--- 2406 Enter arguments here that should be compiled into the kernel 2407 image and used at boot time. If the boot loader provides a 2408 command line at boot time, it is appended to this string to 2409 form the full kernel command line, when the system boots. 2410 2411 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2412 change this behavior. 2413 2414 In most cases, the command line (whether built-in or provided 2415 by the boot loader) should specify the device for the root 2416 file system. 2417 2418config CMDLINE_OVERRIDE 2419 bool "Built-in command line overrides boot loader arguments" 2420 depends on CMDLINE_BOOL 2421 ---help--- 2422 Set this option to 'Y' to have the kernel ignore the boot loader 2423 command line, and use ONLY the built-in command line. 2424 2425 This is used to work around broken boot loaders. This should 2426 be set to 'N' under normal conditions. 2427 2428config MODIFY_LDT_SYSCALL 2429 bool "Enable the LDT (local descriptor table)" if EXPERT 2430 default y 2431 ---help--- 2432 Linux can allow user programs to install a per-process x86 2433 Local Descriptor Table (LDT) using the modify_ldt(2) system 2434 call. This is required to run 16-bit or segmented code such as 2435 DOSEMU or some Wine programs. It is also used by some very old 2436 threading libraries. 2437 2438 Enabling this feature adds a small amount of overhead to 2439 context switches and increases the low-level kernel attack 2440 surface. Disabling it removes the modify_ldt(2) system call. 2441 2442 Saying 'N' here may make sense for embedded or server kernels. 2443 2444source "kernel/livepatch/Kconfig" 2445 2446endmenu 2447 2448config ARCH_HAS_ADD_PAGES 2449 def_bool y 2450 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2451 2452config ARCH_ENABLE_MEMORY_HOTPLUG 2453 def_bool y 2454 depends on X86_64 || (X86_32 && HIGHMEM) 2455 2456config ARCH_ENABLE_MEMORY_HOTREMOVE 2457 def_bool y 2458 depends on MEMORY_HOTPLUG 2459 2460config USE_PERCPU_NUMA_NODE_ID 2461 def_bool y 2462 depends on NUMA 2463 2464config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2465 def_bool y 2466 depends on X86_64 || X86_PAE 2467 2468config ARCH_ENABLE_HUGEPAGE_MIGRATION 2469 def_bool y 2470 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2471 2472config ARCH_ENABLE_THP_MIGRATION 2473 def_bool y 2474 depends on X86_64 && TRANSPARENT_HUGEPAGE 2475 2476menu "Power management and ACPI options" 2477 2478config ARCH_HIBERNATION_HEADER 2479 def_bool y 2480 depends on HIBERNATION 2481 2482source "kernel/power/Kconfig" 2483 2484source "drivers/acpi/Kconfig" 2485 2486source "drivers/sfi/Kconfig" 2487 2488config X86_APM_BOOT 2489 def_bool y 2490 depends on APM 2491 2492menuconfig APM 2493 tristate "APM (Advanced Power Management) BIOS support" 2494 depends on X86_32 && PM_SLEEP 2495 ---help--- 2496 APM is a BIOS specification for saving power using several different 2497 techniques. This is mostly useful for battery powered laptops with 2498 APM compliant BIOSes. If you say Y here, the system time will be 2499 reset after a RESUME operation, the /proc/apm device will provide 2500 battery status information, and user-space programs will receive 2501 notification of APM "events" (e.g. battery status change). 2502 2503 If you select "Y" here, you can disable actual use of the APM 2504 BIOS by passing the "apm=off" option to the kernel at boot time. 2505 2506 Note that the APM support is almost completely disabled for 2507 machines with more than one CPU. 2508 2509 In order to use APM, you will need supporting software. For location 2510 and more information, read <file:Documentation/power/apm-acpi.rst> 2511 and the Battery Powered Linux mini-HOWTO, available from 2512 <http://www.tldp.org/docs.html#howto>. 2513 2514 This driver does not spin down disk drives (see the hdparm(8) 2515 manpage ("man 8 hdparm") for that), and it doesn't turn off 2516 VESA-compliant "green" monitors. 2517 2518 This driver does not support the TI 4000M TravelMate and the ACER 2519 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2520 desktop machines also don't have compliant BIOSes, and this driver 2521 may cause those machines to panic during the boot phase. 2522 2523 Generally, if you don't have a battery in your machine, there isn't 2524 much point in using this driver and you should say N. If you get 2525 random kernel OOPSes or reboots that don't seem to be related to 2526 anything, try disabling/enabling this option (or disabling/enabling 2527 APM in your BIOS). 2528 2529 Some other things you should try when experiencing seemingly random, 2530 "weird" problems: 2531 2532 1) make sure that you have enough swap space and that it is 2533 enabled. 2534 2) pass the "no-hlt" option to the kernel 2535 3) switch on floating point emulation in the kernel and pass 2536 the "no387" option to the kernel 2537 4) pass the "floppy=nodma" option to the kernel 2538 5) pass the "mem=4M" option to the kernel (thereby disabling 2539 all but the first 4 MB of RAM) 2540 6) make sure that the CPU is not over clocked. 2541 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2542 8) disable the cache from your BIOS settings 2543 9) install a fan for the video card or exchange video RAM 2544 10) install a better fan for the CPU 2545 11) exchange RAM chips 2546 12) exchange the motherboard. 2547 2548 To compile this driver as a module, choose M here: the 2549 module will be called apm. 2550 2551if APM 2552 2553config APM_IGNORE_USER_SUSPEND 2554 bool "Ignore USER SUSPEND" 2555 ---help--- 2556 This option will ignore USER SUSPEND requests. On machines with a 2557 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2558 series notebooks, it is necessary to say Y because of a BIOS bug. 2559 2560config APM_DO_ENABLE 2561 bool "Enable PM at boot time" 2562 ---help--- 2563 Enable APM features at boot time. From page 36 of the APM BIOS 2564 specification: "When disabled, the APM BIOS does not automatically 2565 power manage devices, enter the Standby State, enter the Suspend 2566 State, or take power saving steps in response to CPU Idle calls." 2567 This driver will make CPU Idle calls when Linux is idle (unless this 2568 feature is turned off -- see "Do CPU IDLE calls", below). This 2569 should always save battery power, but more complicated APM features 2570 will be dependent on your BIOS implementation. You may need to turn 2571 this option off if your computer hangs at boot time when using APM 2572 support, or if it beeps continuously instead of suspending. Turn 2573 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2574 T400CDT. This is off by default since most machines do fine without 2575 this feature. 2576 2577config APM_CPU_IDLE 2578 depends on CPU_IDLE 2579 bool "Make CPU Idle calls when idle" 2580 ---help--- 2581 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2582 On some machines, this can activate improved power savings, such as 2583 a slowed CPU clock rate, when the machine is idle. These idle calls 2584 are made after the idle loop has run for some length of time (e.g., 2585 333 mS). On some machines, this will cause a hang at boot time or 2586 whenever the CPU becomes idle. (On machines with more than one CPU, 2587 this option does nothing.) 2588 2589config APM_DISPLAY_BLANK 2590 bool "Enable console blanking using APM" 2591 ---help--- 2592 Enable console blanking using the APM. Some laptops can use this to 2593 turn off the LCD backlight when the screen blanker of the Linux 2594 virtual console blanks the screen. Note that this is only used by 2595 the virtual console screen blanker, and won't turn off the backlight 2596 when using the X Window system. This also doesn't have anything to 2597 do with your VESA-compliant power-saving monitor. Further, this 2598 option doesn't work for all laptops -- it might not turn off your 2599 backlight at all, or it might print a lot of errors to the console, 2600 especially if you are using gpm. 2601 2602config APM_ALLOW_INTS 2603 bool "Allow interrupts during APM BIOS calls" 2604 ---help--- 2605 Normally we disable external interrupts while we are making calls to 2606 the APM BIOS as a measure to lessen the effects of a badly behaving 2607 BIOS implementation. The BIOS should reenable interrupts if it 2608 needs to. Unfortunately, some BIOSes do not -- especially those in 2609 many of the newer IBM Thinkpads. If you experience hangs when you 2610 suspend, try setting this to Y. Otherwise, say N. 2611 2612endif # APM 2613 2614source "drivers/cpufreq/Kconfig" 2615 2616source "drivers/cpuidle/Kconfig" 2617 2618source "drivers/idle/Kconfig" 2619 2620endmenu 2621 2622 2623menu "Bus options (PCI etc.)" 2624 2625choice 2626 prompt "PCI access mode" 2627 depends on X86_32 && PCI 2628 default PCI_GOANY 2629 ---help--- 2630 On PCI systems, the BIOS can be used to detect the PCI devices and 2631 determine their configuration. However, some old PCI motherboards 2632 have BIOS bugs and may crash if this is done. Also, some embedded 2633 PCI-based systems don't have any BIOS at all. Linux can also try to 2634 detect the PCI hardware directly without using the BIOS. 2635 2636 With this option, you can specify how Linux should detect the 2637 PCI devices. If you choose "BIOS", the BIOS will be used, 2638 if you choose "Direct", the BIOS won't be used, and if you 2639 choose "MMConfig", then PCI Express MMCONFIG will be used. 2640 If you choose "Any", the kernel will try MMCONFIG, then the 2641 direct access method and falls back to the BIOS if that doesn't 2642 work. If unsure, go with the default, which is "Any". 2643 2644config PCI_GOBIOS 2645 bool "BIOS" 2646 2647config PCI_GOMMCONFIG 2648 bool "MMConfig" 2649 2650config PCI_GODIRECT 2651 bool "Direct" 2652 2653config PCI_GOOLPC 2654 bool "OLPC XO-1" 2655 depends on OLPC 2656 2657config PCI_GOANY 2658 bool "Any" 2659 2660endchoice 2661 2662config PCI_BIOS 2663 def_bool y 2664 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2665 2666# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2667config PCI_DIRECT 2668 def_bool y 2669 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2670 2671config PCI_MMCONFIG 2672 bool "Support mmconfig PCI config space access" if X86_64 2673 default y 2674 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2675 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2676 2677config PCI_OLPC 2678 def_bool y 2679 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2680 2681config PCI_XEN 2682 def_bool y 2683 depends on PCI && XEN 2684 select SWIOTLB_XEN 2685 2686config MMCONF_FAM10H 2687 def_bool y 2688 depends on X86_64 && PCI_MMCONFIG && ACPI 2689 2690config PCI_CNB20LE_QUIRK 2691 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2692 depends on PCI 2693 help 2694 Read the PCI windows out of the CNB20LE host bridge. This allows 2695 PCI hotplug to work on systems with the CNB20LE chipset which do 2696 not have ACPI. 2697 2698 There's no public spec for this chipset, and this functionality 2699 is known to be incomplete. 2700 2701 You should say N unless you know you need this. 2702 2703config ISA_BUS 2704 bool "ISA bus support on modern systems" if EXPERT 2705 help 2706 Expose ISA bus device drivers and options available for selection and 2707 configuration. Enable this option if your target machine has an ISA 2708 bus. ISA is an older system, displaced by PCI and newer bus 2709 architectures -- if your target machine is modern, it probably does 2710 not have an ISA bus. 2711 2712 If unsure, say N. 2713 2714# x86_64 have no ISA slots, but can have ISA-style DMA. 2715config ISA_DMA_API 2716 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2717 default y 2718 help 2719 Enables ISA-style DMA support for devices requiring such controllers. 2720 If unsure, say Y. 2721 2722if X86_32 2723 2724config ISA 2725 bool "ISA support" 2726 ---help--- 2727 Find out whether you have ISA slots on your motherboard. ISA is the 2728 name of a bus system, i.e. the way the CPU talks to the other stuff 2729 inside your box. Other bus systems are PCI, EISA, MicroChannel 2730 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2731 newer boards don't support it. If you have ISA, say Y, otherwise N. 2732 2733config SCx200 2734 tristate "NatSemi SCx200 support" 2735 ---help--- 2736 This provides basic support for National Semiconductor's 2737 (now AMD's) Geode processors. The driver probes for the 2738 PCI-IDs of several on-chip devices, so its a good dependency 2739 for other scx200_* drivers. 2740 2741 If compiled as a module, the driver is named scx200. 2742 2743config SCx200HR_TIMER 2744 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2745 depends on SCx200 2746 default y 2747 ---help--- 2748 This driver provides a clocksource built upon the on-chip 2749 27MHz high-resolution timer. Its also a workaround for 2750 NSC Geode SC-1100's buggy TSC, which loses time when the 2751 processor goes idle (as is done by the scheduler). The 2752 other workaround is idle=poll boot option. 2753 2754config OLPC 2755 bool "One Laptop Per Child support" 2756 depends on !X86_PAE 2757 select GPIOLIB 2758 select OF 2759 select OF_PROMTREE 2760 select IRQ_DOMAIN 2761 select OLPC_EC 2762 ---help--- 2763 Add support for detecting the unique features of the OLPC 2764 XO hardware. 2765 2766config OLPC_XO1_PM 2767 bool "OLPC XO-1 Power Management" 2768 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2769 ---help--- 2770 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2771 2772config OLPC_XO1_RTC 2773 bool "OLPC XO-1 Real Time Clock" 2774 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2775 ---help--- 2776 Add support for the XO-1 real time clock, which can be used as a 2777 programmable wakeup source. 2778 2779config OLPC_XO1_SCI 2780 bool "OLPC XO-1 SCI extras" 2781 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2782 depends on INPUT=y 2783 select POWER_SUPPLY 2784 ---help--- 2785 Add support for SCI-based features of the OLPC XO-1 laptop: 2786 - EC-driven system wakeups 2787 - Power button 2788 - Ebook switch 2789 - Lid switch 2790 - AC adapter status updates 2791 - Battery status updates 2792 2793config OLPC_XO15_SCI 2794 bool "OLPC XO-1.5 SCI extras" 2795 depends on OLPC && ACPI 2796 select POWER_SUPPLY 2797 ---help--- 2798 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2799 - EC-driven system wakeups 2800 - AC adapter status updates 2801 - Battery status updates 2802 2803config ALIX 2804 bool "PCEngines ALIX System Support (LED setup)" 2805 select GPIOLIB 2806 ---help--- 2807 This option enables system support for the PCEngines ALIX. 2808 At present this just sets up LEDs for GPIO control on 2809 ALIX2/3/6 boards. However, other system specific setup should 2810 get added here. 2811 2812 Note: You must still enable the drivers for GPIO and LED support 2813 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2814 2815 Note: You have to set alix.force=1 for boards with Award BIOS. 2816 2817config NET5501 2818 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2819 select GPIOLIB 2820 ---help--- 2821 This option enables system support for the Soekris Engineering net5501. 2822 2823config GEOS 2824 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2825 select GPIOLIB 2826 depends on DMI 2827 ---help--- 2828 This option enables system support for the Traverse Technologies GEOS. 2829 2830config TS5500 2831 bool "Technologic Systems TS-5500 platform support" 2832 depends on MELAN 2833 select CHECK_SIGNATURE 2834 select NEW_LEDS 2835 select LEDS_CLASS 2836 ---help--- 2837 This option enables system support for the Technologic Systems TS-5500. 2838 2839endif # X86_32 2840 2841config AMD_NB 2842 def_bool y 2843 depends on CPU_SUP_AMD && PCI 2844 2845config X86_SYSFB 2846 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2847 help 2848 Firmwares often provide initial graphics framebuffers so the BIOS, 2849 bootloader or kernel can show basic video-output during boot for 2850 user-guidance and debugging. Historically, x86 used the VESA BIOS 2851 Extensions and EFI-framebuffers for this, which are mostly limited 2852 to x86. 2853 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2854 framebuffers so the new generic system-framebuffer drivers can be 2855 used on x86. If the framebuffer is not compatible with the generic 2856 modes, it is advertised as fallback platform framebuffer so legacy 2857 drivers like efifb, vesafb and uvesafb can pick it up. 2858 If this option is not selected, all system framebuffers are always 2859 marked as fallback platform framebuffers as usual. 2860 2861 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2862 not be able to pick up generic system framebuffers if this option 2863 is selected. You are highly encouraged to enable simplefb as 2864 replacement if you select this option. simplefb can correctly deal 2865 with generic system framebuffers. But you should still keep vesafb 2866 and others enabled as fallback if a system framebuffer is 2867 incompatible with simplefb. 2868 2869 If unsure, say Y. 2870 2871endmenu 2872 2873 2874menu "Binary Emulations" 2875 2876config IA32_EMULATION 2877 bool "IA32 Emulation" 2878 depends on X86_64 2879 select ARCH_WANT_OLD_COMPAT_IPC 2880 select BINFMT_ELF 2881 select COMPAT_BINFMT_ELF 2882 select COMPAT_OLD_SIGACTION 2883 ---help--- 2884 Include code to run legacy 32-bit programs under a 2885 64-bit kernel. You should likely turn this on, unless you're 2886 100% sure that you don't have any 32-bit programs left. 2887 2888config IA32_AOUT 2889 tristate "IA32 a.out support" 2890 depends on IA32_EMULATION 2891 depends on BROKEN 2892 ---help--- 2893 Support old a.out binaries in the 32bit emulation. 2894 2895config X86_X32 2896 bool "x32 ABI for 64-bit mode" 2897 depends on X86_64 2898 ---help--- 2899 Include code to run binaries for the x32 native 32-bit ABI 2900 for 64-bit processors. An x32 process gets access to the 2901 full 64-bit register file and wide data path while leaving 2902 pointers at 32 bits for smaller memory footprint. 2903 2904 You will need a recent binutils (2.22 or later) with 2905 elf32_x86_64 support enabled to compile a kernel with this 2906 option set. 2907 2908config COMPAT_32 2909 def_bool y 2910 depends on IA32_EMULATION || X86_32 2911 select HAVE_UID16 2912 select OLD_SIGSUSPEND3 2913 2914config COMPAT 2915 def_bool y 2916 depends on IA32_EMULATION || X86_X32 2917 2918if COMPAT 2919config COMPAT_FOR_U64_ALIGNMENT 2920 def_bool y 2921 2922config SYSVIPC_COMPAT 2923 def_bool y 2924 depends on SYSVIPC 2925endif 2926 2927endmenu 2928 2929 2930config HAVE_ATOMIC_IOMAP 2931 def_bool y 2932 depends on X86_32 2933 2934source "drivers/firmware/Kconfig" 2935 2936source "arch/x86/kvm/Kconfig" 2937