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_WANTS_DYNAMIC_TASK_STRUCT 97 select ARCH_WANT_HUGE_PMD_SHARE 98 select ARCH_WANTS_THP_SWAP if X86_64 99 select BUILDTIME_EXTABLE_SORT 100 select CLKEVT_I8253 101 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 102 select CLOCKSOURCE_WATCHDOG 103 select DCACHE_WORD_ACCESS 104 select EDAC_ATOMIC_SCRUB 105 select EDAC_SUPPORT 106 select GENERIC_CLOCKEVENTS 107 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 108 select GENERIC_CLOCKEVENTS_MIN_ADJUST 109 select GENERIC_CMOS_UPDATE 110 select GENERIC_CPU_AUTOPROBE 111 select GENERIC_CPU_VULNERABILITIES 112 select GENERIC_EARLY_IOREMAP 113 select GENERIC_FIND_FIRST_BIT 114 select GENERIC_IOMAP 115 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 116 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 117 select GENERIC_IRQ_MIGRATION if SMP 118 select GENERIC_IRQ_PROBE 119 select GENERIC_IRQ_RESERVATION_MODE 120 select GENERIC_IRQ_SHOW 121 select GENERIC_PENDING_IRQ if SMP 122 select GENERIC_SMP_IDLE_THREAD 123 select GENERIC_STRNCPY_FROM_USER 124 select GENERIC_STRNLEN_USER 125 select GENERIC_TIME_VSYSCALL 126 select GENERIC_GETTIMEOFDAY 127 select GUP_GET_PTE_LOW_HIGH if X86_PAE 128 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 129 select HAVE_ACPI_APEI if ACPI 130 select HAVE_ACPI_APEI_NMI if ACPI 131 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 132 select HAVE_ARCH_AUDITSYSCALL 133 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 134 select HAVE_ARCH_JUMP_LABEL 135 select HAVE_ARCH_JUMP_LABEL_RELATIVE 136 select HAVE_ARCH_KASAN if X86_64 137 select HAVE_ARCH_KGDB 138 select HAVE_ARCH_MMAP_RND_BITS if MMU 139 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 140 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 141 select HAVE_ARCH_PREL32_RELOCATIONS 142 select HAVE_ARCH_SECCOMP_FILTER 143 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 144 select HAVE_ARCH_STACKLEAK 145 select HAVE_ARCH_TRACEHOOK 146 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 147 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 148 select HAVE_ARCH_VMAP_STACK if X86_64 149 select HAVE_ARCH_WITHIN_STACK_FRAMES 150 select HAVE_ASM_MODVERSIONS 151 select HAVE_CMPXCHG_DOUBLE 152 select HAVE_CMPXCHG_LOCAL 153 select HAVE_CONTEXT_TRACKING if X86_64 154 select HAVE_COPY_THREAD_TLS 155 select HAVE_C_RECORDMCOUNT 156 select HAVE_DEBUG_KMEMLEAK 157 select HAVE_DMA_CONTIGUOUS 158 select HAVE_DYNAMIC_FTRACE 159 select HAVE_DYNAMIC_FTRACE_WITH_REGS 160 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 161 select HAVE_EBPF_JIT 162 select HAVE_EFFICIENT_UNALIGNED_ACCESS 163 select HAVE_EISA 164 select HAVE_EXIT_THREAD 165 select HAVE_FAST_GUP 166 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 167 select HAVE_FTRACE_MCOUNT_RECORD 168 select HAVE_FUNCTION_GRAPH_TRACER 169 select HAVE_FUNCTION_TRACER 170 select HAVE_GCC_PLUGINS 171 select HAVE_HW_BREAKPOINT 172 select HAVE_IDE 173 select HAVE_IOREMAP_PROT 174 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 175 select HAVE_IRQ_TIME_ACCOUNTING 176 select HAVE_KERNEL_BZIP2 177 select HAVE_KERNEL_GZIP 178 select HAVE_KERNEL_LZ4 179 select HAVE_KERNEL_LZMA 180 select HAVE_KERNEL_LZO 181 select HAVE_KERNEL_XZ 182 select HAVE_KPROBES 183 select HAVE_KPROBES_ON_FTRACE 184 select HAVE_FUNCTION_ERROR_INJECTION 185 select HAVE_KRETPROBES 186 select HAVE_KVM 187 select HAVE_LIVEPATCH if X86_64 188 select HAVE_MEMBLOCK_NODE_MAP 189 select HAVE_MIXED_BREAKPOINTS_REGS 190 select HAVE_MOD_ARCH_SPECIFIC 191 select HAVE_MOVE_PMD 192 select HAVE_NMI 193 select HAVE_OPROFILE 194 select HAVE_OPTPROBES 195 select HAVE_PCSPKR_PLATFORM 196 select HAVE_PERF_EVENTS 197 select HAVE_PERF_EVENTS_NMI 198 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 199 select HAVE_PCI 200 select HAVE_PERF_REGS 201 select HAVE_PERF_USER_STACK_DUMP 202 select HAVE_RCU_TABLE_FREE if PARAVIRT 203 select HAVE_REGS_AND_STACK_ACCESS_API 204 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 205 select HAVE_FUNCTION_ARG_ACCESS_API 206 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 207 select HAVE_STACK_VALIDATION if X86_64 208 select HAVE_RSEQ 209 select HAVE_SYSCALL_TRACEPOINTS 210 select HAVE_UNSTABLE_SCHED_CLOCK 211 select HAVE_USER_RETURN_NOTIFIER 212 select HAVE_GENERIC_VDSO 213 select HOTPLUG_SMT if SMP 214 select IRQ_FORCED_THREADING 215 select NEED_SG_DMA_LENGTH 216 select PCI_DOMAINS if PCI 217 select PCI_LOCKLESS_CONFIG if PCI 218 select PERF_EVENTS 219 select RTC_LIB 220 select RTC_MC146818_LIB 221 select SPARSE_IRQ 222 select SRCU 223 select SYSCTL_EXCEPTION_TRACE 224 select THREAD_INFO_IN_TASK 225 select USER_STACKTRACE_SUPPORT 226 select VIRT_TO_BUS 227 select X86_FEATURE_NAMES if PROC_FS 228 select PROC_PID_ARCH_STATUS if PROC_FS 229 230config INSTRUCTION_DECODER 231 def_bool y 232 depends on KPROBES || PERF_EVENTS || UPROBES 233 234config OUTPUT_FORMAT 235 string 236 default "elf32-i386" if X86_32 237 default "elf64-x86-64" if X86_64 238 239config ARCH_DEFCONFIG 240 string 241 default "arch/x86/configs/i386_defconfig" if X86_32 242 default "arch/x86/configs/x86_64_defconfig" if X86_64 243 244config LOCKDEP_SUPPORT 245 def_bool y 246 247config STACKTRACE_SUPPORT 248 def_bool y 249 250config MMU 251 def_bool y 252 253config ARCH_MMAP_RND_BITS_MIN 254 default 28 if 64BIT 255 default 8 256 257config ARCH_MMAP_RND_BITS_MAX 258 default 32 if 64BIT 259 default 16 260 261config ARCH_MMAP_RND_COMPAT_BITS_MIN 262 default 8 263 264config ARCH_MMAP_RND_COMPAT_BITS_MAX 265 default 16 266 267config SBUS 268 bool 269 270config GENERIC_ISA_DMA 271 def_bool y 272 depends on ISA_DMA_API 273 274config GENERIC_BUG 275 def_bool y 276 depends on BUG 277 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 278 279config GENERIC_BUG_RELATIVE_POINTERS 280 bool 281 282config ARCH_MAY_HAVE_PC_FDC 283 def_bool y 284 depends on ISA_DMA_API 285 286config GENERIC_CALIBRATE_DELAY 287 def_bool y 288 289config ARCH_HAS_CPU_RELAX 290 def_bool y 291 292config ARCH_HAS_CACHE_LINE_SIZE 293 def_bool y 294 295config ARCH_HAS_FILTER_PGPROT 296 def_bool y 297 298config HAVE_SETUP_PER_CPU_AREA 299 def_bool y 300 301config NEED_PER_CPU_EMBED_FIRST_CHUNK 302 def_bool y 303 304config NEED_PER_CPU_PAGE_FIRST_CHUNK 305 def_bool y 306 307config ARCH_HIBERNATION_POSSIBLE 308 def_bool y 309 310config ARCH_SUSPEND_POSSIBLE 311 def_bool y 312 313config ARCH_WANT_GENERAL_HUGETLB 314 def_bool y 315 316config ZONE_DMA32 317 def_bool y if X86_64 318 319config AUDIT_ARCH 320 def_bool y if X86_64 321 322config ARCH_SUPPORTS_DEBUG_PAGEALLOC 323 def_bool y 324 325config KASAN_SHADOW_OFFSET 326 hex 327 depends on KASAN 328 default 0xdffffc0000000000 329 330config HAVE_INTEL_TXT 331 def_bool y 332 depends on INTEL_IOMMU && ACPI 333 334config X86_32_SMP 335 def_bool y 336 depends on X86_32 && SMP 337 338config X86_64_SMP 339 def_bool y 340 depends on X86_64 && SMP 341 342config X86_32_LAZY_GS 343 def_bool y 344 depends on X86_32 && !STACKPROTECTOR 345 346config ARCH_SUPPORTS_UPROBES 347 def_bool y 348 349config FIX_EARLYCON_MEM 350 def_bool y 351 352config DYNAMIC_PHYSICAL_MASK 353 bool 354 355config PGTABLE_LEVELS 356 int 357 default 5 if X86_5LEVEL 358 default 4 if X86_64 359 default 3 if X86_PAE 360 default 2 361 362config CC_HAS_SANE_STACKPROTECTOR 363 bool 364 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 365 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 366 help 367 We have to make sure stack protector is unconditionally disabled if 368 the compiler produces broken code. 369 370menu "Processor type and features" 371 372config ZONE_DMA 373 bool "DMA memory allocation support" if EXPERT 374 default y 375 help 376 DMA memory allocation support allows devices with less than 32-bit 377 addressing to allocate within the first 16MB of address space. 378 Disable if no such devices will be used. 379 380 If unsure, say Y. 381 382config SMP 383 bool "Symmetric multi-processing support" 384 ---help--- 385 This enables support for systems with more than one CPU. If you have 386 a system with only one CPU, say N. If you have a system with more 387 than one CPU, say Y. 388 389 If you say N here, the kernel will run on uni- and multiprocessor 390 machines, but will use only one CPU of a multiprocessor machine. If 391 you say Y here, the kernel will run on many, but not all, 392 uniprocessor machines. On a uniprocessor machine, the kernel 393 will run faster if you say N here. 394 395 Note that if you say Y here and choose architecture "586" or 396 "Pentium" under "Processor family", the kernel will not work on 486 397 architectures. Similarly, multiprocessor kernels for the "PPro" 398 architecture may not work on all Pentium based boards. 399 400 People using multiprocessor machines who say Y here should also say 401 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 402 Management" code will be disabled if you say Y here. 403 404 See also <file:Documentation/x86/i386/IO-APIC.rst>, 405 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 406 <http://www.tldp.org/docs.html#howto>. 407 408 If you don't know what to do here, say N. 409 410config X86_FEATURE_NAMES 411 bool "Processor feature human-readable names" if EMBEDDED 412 default y 413 ---help--- 414 This option compiles in a table of x86 feature bits and corresponding 415 names. This is required to support /proc/cpuinfo and a few kernel 416 messages. You can disable this to save space, at the expense of 417 making those few kernel messages show numeric feature bits instead. 418 419 If in doubt, say Y. 420 421config X86_X2APIC 422 bool "Support x2apic" 423 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 424 ---help--- 425 This enables x2apic support on CPUs that have this feature. 426 427 This allows 32-bit apic IDs (so it can support very large systems), 428 and accesses the local apic via MSRs not via mmio. 429 430 If you don't know what to do here, say N. 431 432config X86_MPPARSE 433 bool "Enable MPS table" if ACPI || SFI 434 default y 435 depends on X86_LOCAL_APIC 436 ---help--- 437 For old smp systems that do not have proper acpi support. Newer systems 438 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 439 440config GOLDFISH 441 def_bool y 442 depends on X86_GOLDFISH 443 444config RETPOLINE 445 bool "Avoid speculative indirect branches in kernel" 446 default y 447 select STACK_VALIDATION if HAVE_STACK_VALIDATION 448 help 449 Compile kernel with the retpoline compiler options to guard against 450 kernel-to-user data leaks by avoiding speculative indirect 451 branches. Requires a compiler with -mindirect-branch=thunk-extern 452 support for full protection. The kernel may run slower. 453 454config X86_CPU_RESCTRL 455 bool "x86 CPU resource control support" 456 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 457 select KERNFS 458 help 459 Enable x86 CPU resource control support. 460 461 Provide support for the allocation and monitoring of system resources 462 usage by the CPU. 463 464 Intel calls this Intel Resource Director Technology 465 (Intel(R) RDT). More information about RDT can be found in the 466 Intel x86 Architecture Software Developer Manual. 467 468 AMD calls this AMD Platform Quality of Service (AMD QoS). 469 More information about AMD QoS can be found in the AMD64 Technology 470 Platform Quality of Service Extensions manual. 471 472 Say N if unsure. 473 474if X86_32 475config X86_BIGSMP 476 bool "Support for big SMP systems with more than 8 CPUs" 477 depends on SMP 478 ---help--- 479 This option is needed for the systems that have more than 8 CPUs 480 481config X86_EXTENDED_PLATFORM 482 bool "Support for extended (non-PC) x86 platforms" 483 default y 484 ---help--- 485 If you disable this option then the kernel will only support 486 standard PC platforms. (which covers the vast majority of 487 systems out there.) 488 489 If you enable this option then you'll be able to select support 490 for the following (non-PC) 32 bit x86 platforms: 491 Goldfish (Android emulator) 492 AMD Elan 493 RDC R-321x SoC 494 SGI 320/540 (Visual Workstation) 495 STA2X11-based (e.g. Northville) 496 Moorestown MID devices 497 498 If you have one of these systems, or if you want to build a 499 generic distribution kernel, say Y here - otherwise say N. 500endif 501 502if X86_64 503config X86_EXTENDED_PLATFORM 504 bool "Support for extended (non-PC) x86 platforms" 505 default y 506 ---help--- 507 If you disable this option then the kernel will only support 508 standard PC platforms. (which covers the vast majority of 509 systems out there.) 510 511 If you enable this option then you'll be able to select support 512 for the following (non-PC) 64 bit x86 platforms: 513 Numascale NumaChip 514 ScaleMP vSMP 515 SGI Ultraviolet 516 517 If you have one of these systems, or if you want to build a 518 generic distribution kernel, say Y here - otherwise say N. 519endif 520# This is an alphabetically sorted list of 64 bit extended platforms 521# Please maintain the alphabetic order if and when there are additions 522config X86_NUMACHIP 523 bool "Numascale NumaChip" 524 depends on X86_64 525 depends on X86_EXTENDED_PLATFORM 526 depends on NUMA 527 depends on SMP 528 depends on X86_X2APIC 529 depends on PCI_MMCONFIG 530 ---help--- 531 Adds support for Numascale NumaChip large-SMP systems. Needed to 532 enable more than ~168 cores. 533 If you don't have one of these, you should say N here. 534 535config X86_VSMP 536 bool "ScaleMP vSMP" 537 select HYPERVISOR_GUEST 538 select PARAVIRT 539 depends on X86_64 && PCI 540 depends on X86_EXTENDED_PLATFORM 541 depends on SMP 542 ---help--- 543 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 544 supposed to run on these EM64T-based machines. Only choose this option 545 if you have one of these machines. 546 547config X86_UV 548 bool "SGI Ultraviolet" 549 depends on X86_64 550 depends on X86_EXTENDED_PLATFORM 551 depends on NUMA 552 depends on EFI 553 depends on X86_X2APIC 554 depends on PCI 555 ---help--- 556 This option is needed in order to support SGI Ultraviolet systems. 557 If you don't have one of these, you should say N here. 558 559# Following is an alphabetically sorted list of 32 bit extended platforms 560# Please maintain the alphabetic order if and when there are additions 561 562config X86_GOLDFISH 563 bool "Goldfish (Virtual Platform)" 564 depends on X86_EXTENDED_PLATFORM 565 ---help--- 566 Enable support for the Goldfish virtual platform used primarily 567 for Android development. Unless you are building for the Android 568 Goldfish emulator say N here. 569 570config X86_INTEL_CE 571 bool "CE4100 TV platform" 572 depends on PCI 573 depends on PCI_GODIRECT 574 depends on X86_IO_APIC 575 depends on X86_32 576 depends on X86_EXTENDED_PLATFORM 577 select X86_REBOOTFIXUPS 578 select OF 579 select OF_EARLY_FLATTREE 580 ---help--- 581 Select for the Intel CE media processor (CE4100) SOC. 582 This option compiles in support for the CE4100 SOC for settop 583 boxes and media devices. 584 585config X86_INTEL_MID 586 bool "Intel MID platform support" 587 depends on X86_EXTENDED_PLATFORM 588 depends on X86_PLATFORM_DEVICES 589 depends on PCI 590 depends on X86_64 || (PCI_GOANY && X86_32) 591 depends on X86_IO_APIC 592 select SFI 593 select I2C 594 select DW_APB_TIMER 595 select APB_TIMER 596 select INTEL_SCU_IPC 597 select MFD_INTEL_MSIC 598 ---help--- 599 Select to build a kernel capable of supporting Intel MID (Mobile 600 Internet Device) platform systems which do not have the PCI legacy 601 interfaces. If you are building for a PC class system say N here. 602 603 Intel MID platforms are based on an Intel processor and chipset which 604 consume less power than most of the x86 derivatives. 605 606config X86_INTEL_QUARK 607 bool "Intel Quark platform support" 608 depends on X86_32 609 depends on X86_EXTENDED_PLATFORM 610 depends on X86_PLATFORM_DEVICES 611 depends on X86_TSC 612 depends on PCI 613 depends on PCI_GOANY 614 depends on X86_IO_APIC 615 select IOSF_MBI 616 select INTEL_IMR 617 select COMMON_CLK 618 ---help--- 619 Select to include support for Quark X1000 SoC. 620 Say Y here if you have a Quark based system such as the Arduino 621 compatible Intel Galileo. 622 623config X86_INTEL_LPSS 624 bool "Intel Low Power Subsystem Support" 625 depends on X86 && ACPI && PCI 626 select COMMON_CLK 627 select PINCTRL 628 select IOSF_MBI 629 ---help--- 630 Select to build support for Intel Low Power Subsystem such as 631 found on Intel Lynxpoint PCH. Selecting this option enables 632 things like clock tree (common clock framework) and pincontrol 633 which are needed by the LPSS peripheral drivers. 634 635config X86_AMD_PLATFORM_DEVICE 636 bool "AMD ACPI2Platform devices support" 637 depends on ACPI 638 select COMMON_CLK 639 select PINCTRL 640 ---help--- 641 Select to interpret AMD specific ACPI device to platform device 642 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 643 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 644 implemented under PINCTRL subsystem. 645 646config IOSF_MBI 647 tristate "Intel SoC IOSF Sideband support for SoC platforms" 648 depends on PCI 649 ---help--- 650 This option enables sideband register access support for Intel SoC 651 platforms. On these platforms the IOSF sideband is used in lieu of 652 MSR's for some register accesses, mostly but not limited to thermal 653 and power. Drivers may query the availability of this device to 654 determine if they need the sideband in order to work on these 655 platforms. The sideband is available on the following SoC products. 656 This list is not meant to be exclusive. 657 - BayTrail 658 - Braswell 659 - Quark 660 661 You should say Y if you are running a kernel on one of these SoC's. 662 663config IOSF_MBI_DEBUG 664 bool "Enable IOSF sideband access through debugfs" 665 depends on IOSF_MBI && DEBUG_FS 666 ---help--- 667 Select this option to expose the IOSF sideband access registers (MCR, 668 MDR, MCRX) through debugfs to write and read register information from 669 different units on the SoC. This is most useful for obtaining device 670 state information for debug and analysis. As this is a general access 671 mechanism, users of this option would have specific knowledge of the 672 device they want to access. 673 674 If you don't require the option or are in doubt, say N. 675 676config X86_RDC321X 677 bool "RDC R-321x SoC" 678 depends on X86_32 679 depends on X86_EXTENDED_PLATFORM 680 select M486 681 select X86_REBOOTFIXUPS 682 ---help--- 683 This option is needed for RDC R-321x system-on-chip, also known 684 as R-8610-(G). 685 If you don't have one of these chips, you should say N here. 686 687config X86_32_NON_STANDARD 688 bool "Support non-standard 32-bit SMP architectures" 689 depends on X86_32 && SMP 690 depends on X86_EXTENDED_PLATFORM 691 ---help--- 692 This option compiles in the bigsmp and STA2X11 default 693 subarchitectures. It is intended for a generic binary 694 kernel. If you select them all, kernel will probe it one by 695 one and will fallback to default. 696 697# Alphabetically sorted list of Non standard 32 bit platforms 698 699config X86_SUPPORTS_MEMORY_FAILURE 700 def_bool y 701 # MCE code calls memory_failure(): 702 depends on X86_MCE 703 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 704 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 705 depends on X86_64 || !SPARSEMEM 706 select ARCH_SUPPORTS_MEMORY_FAILURE 707 708config STA2X11 709 bool "STA2X11 Companion Chip Support" 710 depends on X86_32_NON_STANDARD && PCI 711 select SWIOTLB 712 select MFD_STA2X11 713 select GPIOLIB 714 ---help--- 715 This adds support for boards based on the STA2X11 IO-Hub, 716 a.k.a. "ConneXt". The chip is used in place of the standard 717 PC chipset, so all "standard" peripherals are missing. If this 718 option is selected the kernel will still be able to boot on 719 standard PC machines. 720 721config X86_32_IRIS 722 tristate "Eurobraille/Iris poweroff module" 723 depends on X86_32 724 ---help--- 725 The Iris machines from EuroBraille do not have APM or ACPI support 726 to shut themselves down properly. A special I/O sequence is 727 needed to do so, which is what this module does at 728 kernel shutdown. 729 730 This is only for Iris machines from EuroBraille. 731 732 If unused, say N. 733 734config SCHED_OMIT_FRAME_POINTER 735 def_bool y 736 prompt "Single-depth WCHAN output" 737 depends on X86 738 ---help--- 739 Calculate simpler /proc/<PID>/wchan values. If this option 740 is disabled then wchan values will recurse back to the 741 caller function. This provides more accurate wchan values, 742 at the expense of slightly more scheduling overhead. 743 744 If in doubt, say "Y". 745 746menuconfig HYPERVISOR_GUEST 747 bool "Linux guest support" 748 ---help--- 749 Say Y here to enable options for running Linux under various hyper- 750 visors. This option enables basic hypervisor detection and platform 751 setup. 752 753 If you say N, all options in this submenu will be skipped and 754 disabled, and Linux guest support won't be built in. 755 756if HYPERVISOR_GUEST 757 758config PARAVIRT 759 bool "Enable paravirtualization code" 760 ---help--- 761 This changes the kernel so it can modify itself when it is run 762 under a hypervisor, potentially improving performance significantly 763 over full virtualization. However, when run without a hypervisor 764 the kernel is theoretically slower and slightly larger. 765 766config PARAVIRT_XXL 767 bool 768 769config PARAVIRT_DEBUG 770 bool "paravirt-ops debugging" 771 depends on PARAVIRT && DEBUG_KERNEL 772 ---help--- 773 Enable to debug paravirt_ops internals. Specifically, BUG if 774 a paravirt_op is missing when it is called. 775 776config PARAVIRT_SPINLOCKS 777 bool "Paravirtualization layer for spinlocks" 778 depends on PARAVIRT && SMP 779 ---help--- 780 Paravirtualized spinlocks allow a pvops backend to replace the 781 spinlock implementation with something virtualization-friendly 782 (for example, block the virtual CPU rather than spinning). 783 784 It has a minimal impact on native kernels and gives a nice performance 785 benefit on paravirtualized KVM / Xen kernels. 786 787 If you are unsure how to answer this question, answer Y. 788 789config X86_HV_CALLBACK_VECTOR 790 def_bool n 791 792source "arch/x86/xen/Kconfig" 793 794config KVM_GUEST 795 bool "KVM Guest support (including kvmclock)" 796 depends on PARAVIRT 797 select PARAVIRT_CLOCK 798 select ARCH_CPUIDLE_HALTPOLL 799 default y 800 ---help--- 801 This option enables various optimizations for running under the KVM 802 hypervisor. It includes a paravirtualized clock, so that instead 803 of relying on a PIT (or probably other) emulation by the 804 underlying device model, the host provides the guest with 805 timing infrastructure such as time of day, and system time 806 807config ARCH_CPUIDLE_HALTPOLL 808 def_bool n 809 prompt "Disable host haltpoll when loading haltpoll driver" 810 help 811 If virtualized under KVM, disable host haltpoll. 812 813config PVH 814 bool "Support for running PVH guests" 815 ---help--- 816 This option enables the PVH entry point for guest virtual machines 817 as specified in the x86/HVM direct boot ABI. 818 819config KVM_DEBUG_FS 820 bool "Enable debug information for KVM Guests in debugfs" 821 depends on KVM_GUEST && DEBUG_FS 822 ---help--- 823 This option enables collection of various statistics for KVM guest. 824 Statistics are displayed in debugfs filesystem. Enabling this option 825 may incur significant overhead. 826 827config PARAVIRT_TIME_ACCOUNTING 828 bool "Paravirtual steal time accounting" 829 depends on PARAVIRT 830 ---help--- 831 Select this option to enable fine granularity task steal time 832 accounting. Time spent executing other tasks in parallel with 833 the current vCPU is discounted from the vCPU power. To account for 834 that, there can be a small performance impact. 835 836 If in doubt, say N here. 837 838config PARAVIRT_CLOCK 839 bool 840 841config JAILHOUSE_GUEST 842 bool "Jailhouse non-root cell support" 843 depends on X86_64 && PCI 844 select X86_PM_TIMER 845 ---help--- 846 This option allows to run Linux as guest in a Jailhouse non-root 847 cell. You can leave this option disabled if you only want to start 848 Jailhouse and run Linux afterwards in the root cell. 849 850config ACRN_GUEST 851 bool "ACRN Guest support" 852 depends on X86_64 853 select X86_HV_CALLBACK_VECTOR 854 help 855 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 856 a flexible, lightweight reference open-source hypervisor, built with 857 real-time and safety-criticality in mind. It is built for embedded 858 IOT with small footprint and real-time features. More details can be 859 found in https://projectacrn.org/. 860 861endif #HYPERVISOR_GUEST 862 863source "arch/x86/Kconfig.cpu" 864 865config HPET_TIMER 866 def_bool X86_64 867 prompt "HPET Timer Support" if X86_32 868 ---help--- 869 Use the IA-PC HPET (High Precision Event Timer) to manage 870 time in preference to the PIT and RTC, if a HPET is 871 present. 872 HPET is the next generation timer replacing legacy 8254s. 873 The HPET provides a stable time base on SMP 874 systems, unlike the TSC, but it is more expensive to access, 875 as it is off-chip. The interface used is documented 876 in the HPET spec, revision 1. 877 878 You can safely choose Y here. However, HPET will only be 879 activated if the platform and the BIOS support this feature. 880 Otherwise the 8254 will be used for timing services. 881 882 Choose N to continue using the legacy 8254 timer. 883 884config HPET_EMULATE_RTC 885 def_bool y 886 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 887 888config APB_TIMER 889 def_bool y if X86_INTEL_MID 890 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 891 select DW_APB_TIMER 892 depends on X86_INTEL_MID && SFI 893 help 894 APB timer is the replacement for 8254, HPET on X86 MID platforms. 895 The APBT provides a stable time base on SMP 896 systems, unlike the TSC, but it is more expensive to access, 897 as it is off-chip. APB timers are always running regardless of CPU 898 C states, they are used as per CPU clockevent device when possible. 899 900# Mark as expert because too many people got it wrong. 901# The code disables itself when not needed. 902config DMI 903 default y 904 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 905 bool "Enable DMI scanning" if EXPERT 906 ---help--- 907 Enabled scanning of DMI to identify machine quirks. Say Y 908 here unless you have verified that your setup is not 909 affected by entries in the DMI blacklist. Required by PNP 910 BIOS code. 911 912config GART_IOMMU 913 bool "Old AMD GART IOMMU support" 914 select IOMMU_HELPER 915 select SWIOTLB 916 depends on X86_64 && PCI && AMD_NB 917 ---help--- 918 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 919 GART based hardware IOMMUs. 920 921 The GART supports full DMA access for devices with 32-bit access 922 limitations, on systems with more than 3 GB. This is usually needed 923 for USB, sound, many IDE/SATA chipsets and some other devices. 924 925 Newer systems typically have a modern AMD IOMMU, supported via 926 the CONFIG_AMD_IOMMU=y config option. 927 928 In normal configurations this driver is only active when needed: 929 there's more than 3 GB of memory and the system contains a 930 32-bit limited device. 931 932 If unsure, say Y. 933 934config MAXSMP 935 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 936 depends on X86_64 && SMP && DEBUG_KERNEL 937 select CPUMASK_OFFSTACK 938 ---help--- 939 Enable maximum number of CPUS and NUMA Nodes for this architecture. 940 If unsure, say N. 941 942# 943# The maximum number of CPUs supported: 944# 945# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 946# and which can be configured interactively in the 947# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 948# 949# The ranges are different on 32-bit and 64-bit kernels, depending on 950# hardware capabilities and scalability features of the kernel. 951# 952# ( If MAXSMP is enabled we just use the highest possible value and disable 953# interactive configuration. ) 954# 955 956config NR_CPUS_RANGE_BEGIN 957 int 958 default NR_CPUS_RANGE_END if MAXSMP 959 default 1 if !SMP 960 default 2 961 962config NR_CPUS_RANGE_END 963 int 964 depends on X86_32 965 default 64 if SMP && X86_BIGSMP 966 default 8 if SMP && !X86_BIGSMP 967 default 1 if !SMP 968 969config NR_CPUS_RANGE_END 970 int 971 depends on X86_64 972 default 8192 if SMP && CPUMASK_OFFSTACK 973 default 512 if SMP && !CPUMASK_OFFSTACK 974 default 1 if !SMP 975 976config NR_CPUS_DEFAULT 977 int 978 depends on X86_32 979 default 32 if X86_BIGSMP 980 default 8 if SMP 981 default 1 if !SMP 982 983config NR_CPUS_DEFAULT 984 int 985 depends on X86_64 986 default 8192 if MAXSMP 987 default 64 if SMP 988 default 1 if !SMP 989 990config NR_CPUS 991 int "Maximum number of CPUs" if SMP && !MAXSMP 992 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 993 default NR_CPUS_DEFAULT 994 ---help--- 995 This allows you to specify the maximum number of CPUs which this 996 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 997 supported value is 8192, otherwise the maximum value is 512. The 998 minimum value which makes sense is 2. 999 1000 This is purely to save memory: each supported CPU adds about 8KB 1001 to the kernel image. 1002 1003config SCHED_SMT 1004 def_bool y if SMP 1005 1006config SCHED_MC 1007 def_bool y 1008 prompt "Multi-core scheduler support" 1009 depends on SMP 1010 ---help--- 1011 Multi-core scheduler support improves the CPU scheduler's decision 1012 making when dealing with multi-core CPU chips at a cost of slightly 1013 increased overhead in some places. If unsure say N here. 1014 1015config SCHED_MC_PRIO 1016 bool "CPU core priorities scheduler support" 1017 depends on SCHED_MC && CPU_SUP_INTEL 1018 select X86_INTEL_PSTATE 1019 select CPU_FREQ 1020 default y 1021 ---help--- 1022 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1023 core ordering determined at manufacturing time, which allows 1024 certain cores to reach higher turbo frequencies (when running 1025 single threaded workloads) than others. 1026 1027 Enabling this kernel feature teaches the scheduler about 1028 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1029 scheduler's CPU selection logic accordingly, so that higher 1030 overall system performance can be achieved. 1031 1032 This feature will have no effect on CPUs without this feature. 1033 1034 If unsure say Y here. 1035 1036config UP_LATE_INIT 1037 def_bool y 1038 depends on !SMP && X86_LOCAL_APIC 1039 1040config X86_UP_APIC 1041 bool "Local APIC support on uniprocessors" if !PCI_MSI 1042 default PCI_MSI 1043 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1044 ---help--- 1045 A local APIC (Advanced Programmable Interrupt Controller) is an 1046 integrated interrupt controller in the CPU. If you have a single-CPU 1047 system which has a processor with a local APIC, you can say Y here to 1048 enable and use it. If you say Y here even though your machine doesn't 1049 have a local APIC, then the kernel will still run with no slowdown at 1050 all. The local APIC supports CPU-generated self-interrupts (timer, 1051 performance counters), and the NMI watchdog which detects hard 1052 lockups. 1053 1054config X86_UP_IOAPIC 1055 bool "IO-APIC support on uniprocessors" 1056 depends on X86_UP_APIC 1057 ---help--- 1058 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1059 SMP-capable replacement for PC-style interrupt controllers. Most 1060 SMP systems and many recent uniprocessor systems have one. 1061 1062 If you have a single-CPU system with an IO-APIC, you can say Y here 1063 to use it. If you say Y here even though your machine doesn't have 1064 an IO-APIC, then the kernel will still run with no slowdown at all. 1065 1066config X86_LOCAL_APIC 1067 def_bool y 1068 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1069 select IRQ_DOMAIN_HIERARCHY 1070 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1071 1072config X86_IO_APIC 1073 def_bool y 1074 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1075 1076config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1077 bool "Reroute for broken boot IRQs" 1078 depends on X86_IO_APIC 1079 ---help--- 1080 This option enables a workaround that fixes a source of 1081 spurious interrupts. This is recommended when threaded 1082 interrupt handling is used on systems where the generation of 1083 superfluous "boot interrupts" cannot be disabled. 1084 1085 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1086 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1087 kernel does during interrupt handling). On chipsets where this 1088 boot IRQ generation cannot be disabled, this workaround keeps 1089 the original IRQ line masked so that only the equivalent "boot 1090 IRQ" is delivered to the CPUs. The workaround also tells the 1091 kernel to set up the IRQ handler on the boot IRQ line. In this 1092 way only one interrupt is delivered to the kernel. Otherwise 1093 the spurious second interrupt may cause the kernel to bring 1094 down (vital) interrupt lines. 1095 1096 Only affects "broken" chipsets. Interrupt sharing may be 1097 increased on these systems. 1098 1099config X86_MCE 1100 bool "Machine Check / overheating reporting" 1101 select GENERIC_ALLOCATOR 1102 default y 1103 ---help--- 1104 Machine Check support allows the processor to notify the 1105 kernel if it detects a problem (e.g. overheating, data corruption). 1106 The action the kernel takes depends on the severity of the problem, 1107 ranging from warning messages to halting the machine. 1108 1109config X86_MCELOG_LEGACY 1110 bool "Support for deprecated /dev/mcelog character device" 1111 depends on X86_MCE 1112 ---help--- 1113 Enable support for /dev/mcelog which is needed by the old mcelog 1114 userspace logging daemon. Consider switching to the new generation 1115 rasdaemon solution. 1116 1117config X86_MCE_INTEL 1118 def_bool y 1119 prompt "Intel MCE features" 1120 depends on X86_MCE && X86_LOCAL_APIC 1121 ---help--- 1122 Additional support for intel specific MCE features such as 1123 the thermal monitor. 1124 1125config X86_MCE_AMD 1126 def_bool y 1127 prompt "AMD MCE features" 1128 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1129 ---help--- 1130 Additional support for AMD specific MCE features such as 1131 the DRAM Error Threshold. 1132 1133config X86_ANCIENT_MCE 1134 bool "Support for old Pentium 5 / WinChip machine checks" 1135 depends on X86_32 && X86_MCE 1136 ---help--- 1137 Include support for machine check handling on old Pentium 5 or WinChip 1138 systems. These typically need to be enabled explicitly on the command 1139 line. 1140 1141config X86_MCE_THRESHOLD 1142 depends on X86_MCE_AMD || X86_MCE_INTEL 1143 def_bool y 1144 1145config X86_MCE_INJECT 1146 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1147 tristate "Machine check injector support" 1148 ---help--- 1149 Provide support for injecting machine checks for testing purposes. 1150 If you don't know what a machine check is and you don't do kernel 1151 QA it is safe to say n. 1152 1153config X86_THERMAL_VECTOR 1154 def_bool y 1155 depends on X86_MCE_INTEL 1156 1157source "arch/x86/events/Kconfig" 1158 1159config X86_LEGACY_VM86 1160 bool "Legacy VM86 support" 1161 depends on X86_32 1162 ---help--- 1163 This option allows user programs to put the CPU into V8086 1164 mode, which is an 80286-era approximation of 16-bit real mode. 1165 1166 Some very old versions of X and/or vbetool require this option 1167 for user mode setting. Similarly, DOSEMU will use it if 1168 available to accelerate real mode DOS programs. However, any 1169 recent version of DOSEMU, X, or vbetool should be fully 1170 functional even without kernel VM86 support, as they will all 1171 fall back to software emulation. Nevertheless, if you are using 1172 a 16-bit DOS program where 16-bit performance matters, vm86 1173 mode might be faster than emulation and you might want to 1174 enable this option. 1175 1176 Note that any app that works on a 64-bit kernel is unlikely to 1177 need this option, as 64-bit kernels don't, and can't, support 1178 V8086 mode. This option is also unrelated to 16-bit protected 1179 mode and is not needed to run most 16-bit programs under Wine. 1180 1181 Enabling this option increases the complexity of the kernel 1182 and slows down exception handling a tiny bit. 1183 1184 If unsure, say N here. 1185 1186config VM86 1187 bool 1188 default X86_LEGACY_VM86 1189 1190config X86_16BIT 1191 bool "Enable support for 16-bit segments" if EXPERT 1192 default y 1193 depends on MODIFY_LDT_SYSCALL 1194 ---help--- 1195 This option is required by programs like Wine to run 16-bit 1196 protected mode legacy code on x86 processors. Disabling 1197 this option saves about 300 bytes on i386, or around 6K text 1198 plus 16K runtime memory on x86-64, 1199 1200config X86_ESPFIX32 1201 def_bool y 1202 depends on X86_16BIT && X86_32 1203 1204config X86_ESPFIX64 1205 def_bool y 1206 depends on X86_16BIT && X86_64 1207 1208config X86_VSYSCALL_EMULATION 1209 bool "Enable vsyscall emulation" if EXPERT 1210 default y 1211 depends on X86_64 1212 ---help--- 1213 This enables emulation of the legacy vsyscall page. Disabling 1214 it is roughly equivalent to booting with vsyscall=none, except 1215 that it will also disable the helpful warning if a program 1216 tries to use a vsyscall. With this option set to N, offending 1217 programs will just segfault, citing addresses of the form 1218 0xffffffffff600?00. 1219 1220 This option is required by many programs built before 2013, and 1221 care should be used even with newer programs if set to N. 1222 1223 Disabling this option saves about 7K of kernel size and 1224 possibly 4K of additional runtime pagetable memory. 1225 1226config X86_IOPL_IOPERM 1227 bool "IOPERM and IOPL Emulation" 1228 default y 1229 ---help--- 1230 This enables the ioperm() and iopl() syscalls which are necessary 1231 for legacy applications. 1232 1233 Legacy IOPL support is an overbroad mechanism which allows user 1234 space aside of accessing all 65536 I/O ports also to disable 1235 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1236 capabilities and permission from potentially active security 1237 modules. 1238 1239 The emulation restricts the functionality of the syscall to 1240 only allowing the full range I/O port access, but prevents the 1241 ability to disable interrupts from user space which would be 1242 granted if the hardware IOPL mechanism would be used. 1243 1244config TOSHIBA 1245 tristate "Toshiba Laptop support" 1246 depends on X86_32 1247 ---help--- 1248 This adds a driver to safely access the System Management Mode of 1249 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1250 not work on models with a Phoenix BIOS. The System Management Mode 1251 is used to set the BIOS and power saving options on Toshiba portables. 1252 1253 For information on utilities to make use of this driver see the 1254 Toshiba Linux utilities web site at: 1255 <http://www.buzzard.org.uk/toshiba/>. 1256 1257 Say Y if you intend to run this kernel on a Toshiba portable. 1258 Say N otherwise. 1259 1260config I8K 1261 tristate "Dell i8k legacy laptop support" 1262 select HWMON 1263 select SENSORS_DELL_SMM 1264 ---help--- 1265 This option enables legacy /proc/i8k userspace interface in hwmon 1266 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1267 temperature and allows controlling fan speeds of Dell laptops via 1268 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1269 it reports also power and hotkey status. For fan speed control is 1270 needed userspace package i8kutils. 1271 1272 Say Y if you intend to run this kernel on old Dell laptops or want to 1273 use userspace package i8kutils. 1274 Say N otherwise. 1275 1276config X86_REBOOTFIXUPS 1277 bool "Enable X86 board specific fixups for reboot" 1278 depends on X86_32 1279 ---help--- 1280 This enables chipset and/or board specific fixups to be done 1281 in order to get reboot to work correctly. This is only needed on 1282 some combinations of hardware and BIOS. The symptom, for which 1283 this config is intended, is when reboot ends with a stalled/hung 1284 system. 1285 1286 Currently, the only fixup is for the Geode machines using 1287 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1288 1289 Say Y if you want to enable the fixup. Currently, it's safe to 1290 enable this option even if you don't need it. 1291 Say N otherwise. 1292 1293config MICROCODE 1294 bool "CPU microcode loading support" 1295 default y 1296 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1297 select FW_LOADER 1298 ---help--- 1299 If you say Y here, you will be able to update the microcode on 1300 Intel and AMD processors. The Intel support is for the IA32 family, 1301 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1302 AMD support is for families 0x10 and later. You will obviously need 1303 the actual microcode binary data itself which is not shipped with 1304 the Linux kernel. 1305 1306 The preferred method to load microcode from a detached initrd is described 1307 in Documentation/x86/microcode.rst. For that you need to enable 1308 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1309 initrd for microcode blobs. 1310 1311 In addition, you can build the microcode into the kernel. For that you 1312 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1313 config option. 1314 1315config MICROCODE_INTEL 1316 bool "Intel microcode loading support" 1317 depends on MICROCODE 1318 default MICROCODE 1319 select FW_LOADER 1320 ---help--- 1321 This options enables microcode patch loading support for Intel 1322 processors. 1323 1324 For the current Intel microcode data package go to 1325 <https://downloadcenter.intel.com> and search for 1326 'Linux Processor Microcode Data File'. 1327 1328config MICROCODE_AMD 1329 bool "AMD microcode loading support" 1330 depends on MICROCODE 1331 select FW_LOADER 1332 ---help--- 1333 If you select this option, microcode patch loading support for AMD 1334 processors will be enabled. 1335 1336config MICROCODE_OLD_INTERFACE 1337 bool "Ancient loading interface (DEPRECATED)" 1338 default n 1339 depends on MICROCODE 1340 ---help--- 1341 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1342 which was used by userspace tools like iucode_tool and microcode.ctl. 1343 It is inadequate because it runs too late to be able to properly 1344 load microcode on a machine and it needs special tools. Instead, you 1345 should've switched to the early loading method with the initrd or 1346 builtin microcode by now: Documentation/x86/microcode.rst 1347 1348config X86_MSR 1349 tristate "/dev/cpu/*/msr - Model-specific register support" 1350 ---help--- 1351 This device gives privileged processes access to the x86 1352 Model-Specific Registers (MSRs). It is a character device with 1353 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1354 MSR accesses are directed to a specific CPU on multi-processor 1355 systems. 1356 1357config X86_CPUID 1358 tristate "/dev/cpu/*/cpuid - CPU information support" 1359 ---help--- 1360 This device gives processes access to the x86 CPUID instruction to 1361 be executed on a specific processor. It is a character device 1362 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1363 /dev/cpu/31/cpuid. 1364 1365choice 1366 prompt "High Memory Support" 1367 default HIGHMEM4G 1368 depends on X86_32 1369 1370config NOHIGHMEM 1371 bool "off" 1372 ---help--- 1373 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1374 However, the address space of 32-bit x86 processors is only 4 1375 Gigabytes large. That means that, if you have a large amount of 1376 physical memory, not all of it can be "permanently mapped" by the 1377 kernel. The physical memory that's not permanently mapped is called 1378 "high memory". 1379 1380 If you are compiling a kernel which will never run on a machine with 1381 more than 1 Gigabyte total physical RAM, answer "off" here (default 1382 choice and suitable for most users). This will result in a "3GB/1GB" 1383 split: 3GB are mapped so that each process sees a 3GB virtual memory 1384 space and the remaining part of the 4GB virtual memory space is used 1385 by the kernel to permanently map as much physical memory as 1386 possible. 1387 1388 If the machine has between 1 and 4 Gigabytes physical RAM, then 1389 answer "4GB" here. 1390 1391 If more than 4 Gigabytes is used then answer "64GB" here. This 1392 selection turns Intel PAE (Physical Address Extension) mode on. 1393 PAE implements 3-level paging on IA32 processors. PAE is fully 1394 supported by Linux, PAE mode is implemented on all recent Intel 1395 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1396 then the kernel will not boot on CPUs that don't support PAE! 1397 1398 The actual amount of total physical memory will either be 1399 auto detected or can be forced by using a kernel command line option 1400 such as "mem=256M". (Try "man bootparam" or see the documentation of 1401 your boot loader (lilo or loadlin) about how to pass options to the 1402 kernel at boot time.) 1403 1404 If unsure, say "off". 1405 1406config HIGHMEM4G 1407 bool "4GB" 1408 ---help--- 1409 Select this if you have a 32-bit processor and between 1 and 4 1410 gigabytes of physical RAM. 1411 1412config HIGHMEM64G 1413 bool "64GB" 1414 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1415 select X86_PAE 1416 ---help--- 1417 Select this if you have a 32-bit processor and more than 4 1418 gigabytes of physical RAM. 1419 1420endchoice 1421 1422choice 1423 prompt "Memory split" if EXPERT 1424 default VMSPLIT_3G 1425 depends on X86_32 1426 ---help--- 1427 Select the desired split between kernel and user memory. 1428 1429 If the address range available to the kernel is less than the 1430 physical memory installed, the remaining memory will be available 1431 as "high memory". Accessing high memory is a little more costly 1432 than low memory, as it needs to be mapped into the kernel first. 1433 Note that increasing the kernel address space limits the range 1434 available to user programs, making the address space there 1435 tighter. Selecting anything other than the default 3G/1G split 1436 will also likely make your kernel incompatible with binary-only 1437 kernel modules. 1438 1439 If you are not absolutely sure what you are doing, leave this 1440 option alone! 1441 1442 config VMSPLIT_3G 1443 bool "3G/1G user/kernel split" 1444 config VMSPLIT_3G_OPT 1445 depends on !X86_PAE 1446 bool "3G/1G user/kernel split (for full 1G low memory)" 1447 config VMSPLIT_2G 1448 bool "2G/2G user/kernel split" 1449 config VMSPLIT_2G_OPT 1450 depends on !X86_PAE 1451 bool "2G/2G user/kernel split (for full 2G low memory)" 1452 config VMSPLIT_1G 1453 bool "1G/3G user/kernel split" 1454endchoice 1455 1456config PAGE_OFFSET 1457 hex 1458 default 0xB0000000 if VMSPLIT_3G_OPT 1459 default 0x80000000 if VMSPLIT_2G 1460 default 0x78000000 if VMSPLIT_2G_OPT 1461 default 0x40000000 if VMSPLIT_1G 1462 default 0xC0000000 1463 depends on X86_32 1464 1465config HIGHMEM 1466 def_bool y 1467 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1468 1469config X86_PAE 1470 bool "PAE (Physical Address Extension) Support" 1471 depends on X86_32 && !HIGHMEM4G 1472 select PHYS_ADDR_T_64BIT 1473 select SWIOTLB 1474 ---help--- 1475 PAE is required for NX support, and furthermore enables 1476 larger swapspace support for non-overcommit purposes. It 1477 has the cost of more pagetable lookup overhead, and also 1478 consumes more pagetable space per process. 1479 1480config X86_5LEVEL 1481 bool "Enable 5-level page tables support" 1482 default y 1483 select DYNAMIC_MEMORY_LAYOUT 1484 select SPARSEMEM_VMEMMAP 1485 depends on X86_64 1486 ---help--- 1487 5-level paging enables access to larger address space: 1488 upto 128 PiB of virtual address space and 4 PiB of 1489 physical address space. 1490 1491 It will be supported by future Intel CPUs. 1492 1493 A kernel with the option enabled can be booted on machines that 1494 support 4- or 5-level paging. 1495 1496 See Documentation/x86/x86_64/5level-paging.rst for more 1497 information. 1498 1499 Say N if unsure. 1500 1501config X86_DIRECT_GBPAGES 1502 def_bool y 1503 depends on X86_64 1504 ---help--- 1505 Certain kernel features effectively disable kernel 1506 linear 1 GB mappings (even if the CPU otherwise 1507 supports them), so don't confuse the user by printing 1508 that we have them enabled. 1509 1510config X86_CPA_STATISTICS 1511 bool "Enable statistic for Change Page Attribute" 1512 depends on DEBUG_FS 1513 ---help--- 1514 Expose statistics about the Change Page Attribute mechanims, which 1515 helps to determine the effectiveness of preserving large and huge 1516 page mappings when mapping protections are changed. 1517 1518config AMD_MEM_ENCRYPT 1519 bool "AMD Secure Memory Encryption (SME) support" 1520 depends on X86_64 && CPU_SUP_AMD 1521 select DYNAMIC_PHYSICAL_MASK 1522 select ARCH_USE_MEMREMAP_PROT 1523 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1524 ---help--- 1525 Say yes to enable support for the encryption of system memory. 1526 This requires an AMD processor that supports Secure Memory 1527 Encryption (SME). 1528 1529config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1530 bool "Activate AMD Secure Memory Encryption (SME) by default" 1531 default y 1532 depends on AMD_MEM_ENCRYPT 1533 ---help--- 1534 Say yes to have system memory encrypted by default if running on 1535 an AMD processor that supports Secure Memory Encryption (SME). 1536 1537 If set to Y, then the encryption of system memory can be 1538 deactivated with the mem_encrypt=off command line option. 1539 1540 If set to N, then the encryption of system memory can be 1541 activated with the mem_encrypt=on command line option. 1542 1543# Common NUMA Features 1544config NUMA 1545 bool "Numa Memory Allocation and Scheduler Support" 1546 depends on SMP 1547 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1548 default y if X86_BIGSMP 1549 ---help--- 1550 Enable NUMA (Non Uniform Memory Access) support. 1551 1552 The kernel will try to allocate memory used by a CPU on the 1553 local memory controller of the CPU and add some more 1554 NUMA awareness to the kernel. 1555 1556 For 64-bit this is recommended if the system is Intel Core i7 1557 (or later), AMD Opteron, or EM64T NUMA. 1558 1559 For 32-bit this is only needed if you boot a 32-bit 1560 kernel on a 64-bit NUMA platform. 1561 1562 Otherwise, you should say N. 1563 1564config AMD_NUMA 1565 def_bool y 1566 prompt "Old style AMD Opteron NUMA detection" 1567 depends on X86_64 && NUMA && PCI 1568 ---help--- 1569 Enable AMD NUMA node topology detection. You should say Y here if 1570 you have a multi processor AMD system. This uses an old method to 1571 read the NUMA configuration directly from the builtin Northbridge 1572 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1573 which also takes priority if both are compiled in. 1574 1575config X86_64_ACPI_NUMA 1576 def_bool y 1577 prompt "ACPI NUMA detection" 1578 depends on X86_64 && NUMA && ACPI && PCI 1579 select ACPI_NUMA 1580 ---help--- 1581 Enable ACPI SRAT based node topology detection. 1582 1583# Some NUMA nodes have memory ranges that span 1584# other nodes. Even though a pfn is valid and 1585# between a node's start and end pfns, it may not 1586# reside on that node. See memmap_init_zone() 1587# for details. 1588config NODES_SPAN_OTHER_NODES 1589 def_bool y 1590 depends on X86_64_ACPI_NUMA 1591 1592config NUMA_EMU 1593 bool "NUMA emulation" 1594 depends on NUMA 1595 ---help--- 1596 Enable NUMA emulation. A flat machine will be split 1597 into virtual nodes when booted with "numa=fake=N", where N is the 1598 number of nodes. This is only useful for debugging. 1599 1600config NODES_SHIFT 1601 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1602 range 1 10 1603 default "10" if MAXSMP 1604 default "6" if X86_64 1605 default "3" 1606 depends on NEED_MULTIPLE_NODES 1607 ---help--- 1608 Specify the maximum number of NUMA Nodes available on the target 1609 system. Increases memory reserved to accommodate various tables. 1610 1611config ARCH_HAVE_MEMORY_PRESENT 1612 def_bool y 1613 depends on X86_32 && DISCONTIGMEM 1614 1615config ARCH_FLATMEM_ENABLE 1616 def_bool y 1617 depends on X86_32 && !NUMA 1618 1619config ARCH_DISCONTIGMEM_ENABLE 1620 def_bool n 1621 depends on NUMA && X86_32 1622 depends on BROKEN 1623 1624config ARCH_SPARSEMEM_ENABLE 1625 def_bool y 1626 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1627 select SPARSEMEM_STATIC if X86_32 1628 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1629 1630config ARCH_SPARSEMEM_DEFAULT 1631 def_bool X86_64 || (NUMA && X86_32) 1632 1633config ARCH_SELECT_MEMORY_MODEL 1634 def_bool y 1635 depends on ARCH_SPARSEMEM_ENABLE 1636 1637config ARCH_MEMORY_PROBE 1638 bool "Enable sysfs memory/probe interface" 1639 depends on X86_64 && MEMORY_HOTPLUG 1640 help 1641 This option enables a sysfs memory/probe interface for testing. 1642 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1643 If you are unsure how to answer this question, answer N. 1644 1645config ARCH_PROC_KCORE_TEXT 1646 def_bool y 1647 depends on X86_64 && PROC_KCORE 1648 1649config ILLEGAL_POINTER_VALUE 1650 hex 1651 default 0 if X86_32 1652 default 0xdead000000000000 if X86_64 1653 1654config X86_PMEM_LEGACY_DEVICE 1655 bool 1656 1657config X86_PMEM_LEGACY 1658 tristate "Support non-standard NVDIMMs and ADR protected memory" 1659 depends on PHYS_ADDR_T_64BIT 1660 depends on BLK_DEV 1661 select X86_PMEM_LEGACY_DEVICE 1662 select LIBNVDIMM 1663 help 1664 Treat memory marked using the non-standard e820 type of 12 as used 1665 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1666 The kernel will offer these regions to the 'pmem' driver so 1667 they can be used for persistent storage. 1668 1669 Say Y if unsure. 1670 1671config HIGHPTE 1672 bool "Allocate 3rd-level pagetables from highmem" 1673 depends on HIGHMEM 1674 ---help--- 1675 The VM uses one page table entry for each page of physical memory. 1676 For systems with a lot of RAM, this can be wasteful of precious 1677 low memory. Setting this option will put user-space page table 1678 entries in high memory. 1679 1680config X86_CHECK_BIOS_CORRUPTION 1681 bool "Check for low memory corruption" 1682 ---help--- 1683 Periodically check for memory corruption in low memory, which 1684 is suspected to be caused by BIOS. Even when enabled in the 1685 configuration, it is disabled at runtime. Enable it by 1686 setting "memory_corruption_check=1" on the kernel command 1687 line. By default it scans the low 64k of memory every 60 1688 seconds; see the memory_corruption_check_size and 1689 memory_corruption_check_period parameters in 1690 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1691 1692 When enabled with the default parameters, this option has 1693 almost no overhead, as it reserves a relatively small amount 1694 of memory and scans it infrequently. It both detects corruption 1695 and prevents it from affecting the running system. 1696 1697 It is, however, intended as a diagnostic tool; if repeatable 1698 BIOS-originated corruption always affects the same memory, 1699 you can use memmap= to prevent the kernel from using that 1700 memory. 1701 1702config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1703 bool "Set the default setting of memory_corruption_check" 1704 depends on X86_CHECK_BIOS_CORRUPTION 1705 default y 1706 ---help--- 1707 Set whether the default state of memory_corruption_check is 1708 on or off. 1709 1710config X86_RESERVE_LOW 1711 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1712 default 64 1713 range 4 640 1714 ---help--- 1715 Specify the amount of low memory to reserve for the BIOS. 1716 1717 The first page contains BIOS data structures that the kernel 1718 must not use, so that page must always be reserved. 1719 1720 By default we reserve the first 64K of physical RAM, as a 1721 number of BIOSes are known to corrupt that memory range 1722 during events such as suspend/resume or monitor cable 1723 insertion, so it must not be used by the kernel. 1724 1725 You can set this to 4 if you are absolutely sure that you 1726 trust the BIOS to get all its memory reservations and usages 1727 right. If you know your BIOS have problems beyond the 1728 default 64K area, you can set this to 640 to avoid using the 1729 entire low memory range. 1730 1731 If you have doubts about the BIOS (e.g. suspend/resume does 1732 not work or there's kernel crashes after certain hardware 1733 hotplug events) then you might want to enable 1734 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1735 typical corruption patterns. 1736 1737 Leave this to the default value of 64 if you are unsure. 1738 1739config MATH_EMULATION 1740 bool 1741 depends on MODIFY_LDT_SYSCALL 1742 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1743 ---help--- 1744 Linux can emulate a math coprocessor (used for floating point 1745 operations) if you don't have one. 486DX and Pentium processors have 1746 a math coprocessor built in, 486SX and 386 do not, unless you added 1747 a 487DX or 387, respectively. (The messages during boot time can 1748 give you some hints here ["man dmesg"].) Everyone needs either a 1749 coprocessor or this emulation. 1750 1751 If you don't have a math coprocessor, you need to say Y here; if you 1752 say Y here even though you have a coprocessor, the coprocessor will 1753 be used nevertheless. (This behavior can be changed with the kernel 1754 command line option "no387", which comes handy if your coprocessor 1755 is broken. Try "man bootparam" or see the documentation of your boot 1756 loader (lilo or loadlin) about how to pass options to the kernel at 1757 boot time.) This means that it is a good idea to say Y here if you 1758 intend to use this kernel on different machines. 1759 1760 More information about the internals of the Linux math coprocessor 1761 emulation can be found in <file:arch/x86/math-emu/README>. 1762 1763 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1764 kernel, it won't hurt. 1765 1766config MTRR 1767 def_bool y 1768 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1769 ---help--- 1770 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1771 the Memory Type Range Registers (MTRRs) may be used to control 1772 processor access to memory ranges. This is most useful if you have 1773 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1774 allows bus write transfers to be combined into a larger transfer 1775 before bursting over the PCI/AGP bus. This can increase performance 1776 of image write operations 2.5 times or more. Saying Y here creates a 1777 /proc/mtrr file which may be used to manipulate your processor's 1778 MTRRs. Typically the X server should use this. 1779 1780 This code has a reasonably generic interface so that similar 1781 control registers on other processors can be easily supported 1782 as well: 1783 1784 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1785 Registers (ARRs) which provide a similar functionality to MTRRs. For 1786 these, the ARRs are used to emulate the MTRRs. 1787 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1788 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1789 write-combining. All of these processors are supported by this code 1790 and it makes sense to say Y here if you have one of them. 1791 1792 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1793 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1794 can lead to all sorts of problems, so it's good to say Y here. 1795 1796 You can safely say Y even if your machine doesn't have MTRRs, you'll 1797 just add about 9 KB to your kernel. 1798 1799 See <file:Documentation/x86/mtrr.rst> for more information. 1800 1801config MTRR_SANITIZER 1802 def_bool y 1803 prompt "MTRR cleanup support" 1804 depends on MTRR 1805 ---help--- 1806 Convert MTRR layout from continuous to discrete, so X drivers can 1807 add writeback entries. 1808 1809 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1810 The largest mtrr entry size for a continuous block can be set with 1811 mtrr_chunk_size. 1812 1813 If unsure, say Y. 1814 1815config MTRR_SANITIZER_ENABLE_DEFAULT 1816 int "MTRR cleanup enable value (0-1)" 1817 range 0 1 1818 default "0" 1819 depends on MTRR_SANITIZER 1820 ---help--- 1821 Enable mtrr cleanup default value 1822 1823config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1824 int "MTRR cleanup spare reg num (0-7)" 1825 range 0 7 1826 default "1" 1827 depends on MTRR_SANITIZER 1828 ---help--- 1829 mtrr cleanup spare entries default, it can be changed via 1830 mtrr_spare_reg_nr=N on the kernel command line. 1831 1832config X86_PAT 1833 def_bool y 1834 prompt "x86 PAT support" if EXPERT 1835 depends on MTRR 1836 ---help--- 1837 Use PAT attributes to setup page level cache control. 1838 1839 PATs are the modern equivalents of MTRRs and are much more 1840 flexible than MTRRs. 1841 1842 Say N here if you see bootup problems (boot crash, boot hang, 1843 spontaneous reboots) or a non-working video driver. 1844 1845 If unsure, say Y. 1846 1847config ARCH_USES_PG_UNCACHED 1848 def_bool y 1849 depends on X86_PAT 1850 1851config ARCH_RANDOM 1852 def_bool y 1853 prompt "x86 architectural random number generator" if EXPERT 1854 ---help--- 1855 Enable the x86 architectural RDRAND instruction 1856 (Intel Bull Mountain technology) to generate random numbers. 1857 If supported, this is a high bandwidth, cryptographically 1858 secure hardware random number generator. 1859 1860config X86_SMAP 1861 def_bool y 1862 prompt "Supervisor Mode Access Prevention" if EXPERT 1863 ---help--- 1864 Supervisor Mode Access Prevention (SMAP) is a security 1865 feature in newer Intel processors. There is a small 1866 performance cost if this enabled and turned on; there is 1867 also a small increase in the kernel size if this is enabled. 1868 1869 If unsure, say Y. 1870 1871config X86_UMIP 1872 def_bool y 1873 depends on CPU_SUP_INTEL || CPU_SUP_AMD 1874 prompt "User Mode Instruction Prevention" if EXPERT 1875 ---help--- 1876 User Mode Instruction Prevention (UMIP) is a security feature in 1877 some x86 processors. If enabled, a general protection fault is 1878 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1879 executed in user mode. These instructions unnecessarily expose 1880 information about the hardware state. 1881 1882 The vast majority of applications do not use these instructions. 1883 For the very few that do, software emulation is provided in 1884 specific cases in protected and virtual-8086 modes. Emulated 1885 results are dummy. 1886 1887config X86_INTEL_MPX 1888 prompt "Intel MPX (Memory Protection Extensions)" 1889 def_bool n 1890 # Note: only available in 64-bit mode due to VMA flags shortage 1891 depends on CPU_SUP_INTEL && X86_64 1892 select ARCH_USES_HIGH_VMA_FLAGS 1893 ---help--- 1894 MPX provides hardware features that can be used in 1895 conjunction with compiler-instrumented code to check 1896 memory references. It is designed to detect buffer 1897 overflow or underflow bugs. 1898 1899 This option enables running applications which are 1900 instrumented or otherwise use MPX. It does not use MPX 1901 itself inside the kernel or to protect the kernel 1902 against bad memory references. 1903 1904 Enabling this option will make the kernel larger: 1905 ~8k of kernel text and 36 bytes of data on a 64-bit 1906 defconfig. It adds a long to the 'mm_struct' which 1907 will increase the kernel memory overhead of each 1908 process and adds some branches to paths used during 1909 exec() and munmap(). 1910 1911 For details, see Documentation/x86/intel_mpx.rst 1912 1913 If unsure, say N. 1914 1915config X86_INTEL_MEMORY_PROTECTION_KEYS 1916 prompt "Intel Memory Protection Keys" 1917 def_bool y 1918 # Note: only available in 64-bit mode 1919 depends on CPU_SUP_INTEL && X86_64 1920 select ARCH_USES_HIGH_VMA_FLAGS 1921 select ARCH_HAS_PKEYS 1922 ---help--- 1923 Memory Protection Keys provides a mechanism for enforcing 1924 page-based protections, but without requiring modification of the 1925 page tables when an application changes protection domains. 1926 1927 For details, see Documentation/core-api/protection-keys.rst 1928 1929 If unsure, say y. 1930 1931choice 1932 prompt "TSX enable mode" 1933 depends on CPU_SUP_INTEL 1934 default X86_INTEL_TSX_MODE_OFF 1935 help 1936 Intel's TSX (Transactional Synchronization Extensions) feature 1937 allows to optimize locking protocols through lock elision which 1938 can lead to a noticeable performance boost. 1939 1940 On the other hand it has been shown that TSX can be exploited 1941 to form side channel attacks (e.g. TAA) and chances are there 1942 will be more of those attacks discovered in the future. 1943 1944 Therefore TSX is not enabled by default (aka tsx=off). An admin 1945 might override this decision by tsx=on the command line parameter. 1946 Even with TSX enabled, the kernel will attempt to enable the best 1947 possible TAA mitigation setting depending on the microcode available 1948 for the particular machine. 1949 1950 This option allows to set the default tsx mode between tsx=on, =off 1951 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1952 details. 1953 1954 Say off if not sure, auto if TSX is in use but it should be used on safe 1955 platforms or on if TSX is in use and the security aspect of tsx is not 1956 relevant. 1957 1958config X86_INTEL_TSX_MODE_OFF 1959 bool "off" 1960 help 1961 TSX is disabled if possible - equals to tsx=off command line parameter. 1962 1963config X86_INTEL_TSX_MODE_ON 1964 bool "on" 1965 help 1966 TSX is always enabled on TSX capable HW - equals the tsx=on command 1967 line parameter. 1968 1969config X86_INTEL_TSX_MODE_AUTO 1970 bool "auto" 1971 help 1972 TSX is enabled on TSX capable HW that is believed to be safe against 1973 side channel attacks- equals the tsx=auto command line parameter. 1974endchoice 1975 1976config EFI 1977 bool "EFI runtime service support" 1978 depends on ACPI 1979 select UCS2_STRING 1980 select EFI_RUNTIME_WRAPPERS 1981 ---help--- 1982 This enables the kernel to use EFI runtime services that are 1983 available (such as the EFI variable services). 1984 1985 This option is only useful on systems that have EFI firmware. 1986 In addition, you should use the latest ELILO loader available 1987 at <http://elilo.sourceforge.net> in order to take advantage 1988 of EFI runtime services. However, even with this option, the 1989 resultant kernel should continue to boot on existing non-EFI 1990 platforms. 1991 1992config EFI_STUB 1993 bool "EFI stub support" 1994 depends on EFI && !X86_USE_3DNOW 1995 select RELOCATABLE 1996 ---help--- 1997 This kernel feature allows a bzImage to be loaded directly 1998 by EFI firmware without the use of a bootloader. 1999 2000 See Documentation/admin-guide/efi-stub.rst for more information. 2001 2002config EFI_MIXED 2003 bool "EFI mixed-mode support" 2004 depends on EFI_STUB && X86_64 2005 ---help--- 2006 Enabling this feature allows a 64-bit kernel to be booted 2007 on a 32-bit firmware, provided that your CPU supports 64-bit 2008 mode. 2009 2010 Note that it is not possible to boot a mixed-mode enabled 2011 kernel via the EFI boot stub - a bootloader that supports 2012 the EFI handover protocol must be used. 2013 2014 If unsure, say N. 2015 2016config SECCOMP 2017 def_bool y 2018 prompt "Enable seccomp to safely compute untrusted bytecode" 2019 ---help--- 2020 This kernel feature is useful for number crunching applications 2021 that may need to compute untrusted bytecode during their 2022 execution. By using pipes or other transports made available to 2023 the process as file descriptors supporting the read/write 2024 syscalls, it's possible to isolate those applications in 2025 their own address space using seccomp. Once seccomp is 2026 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 2027 and the task is only allowed to execute a few safe syscalls 2028 defined by each seccomp mode. 2029 2030 If unsure, say Y. Only embedded should say N here. 2031 2032source "kernel/Kconfig.hz" 2033 2034config KEXEC 2035 bool "kexec system call" 2036 select KEXEC_CORE 2037 ---help--- 2038 kexec is a system call that implements the ability to shutdown your 2039 current kernel, and to start another kernel. It is like a reboot 2040 but it is independent of the system firmware. And like a reboot 2041 you can start any kernel with it, not just Linux. 2042 2043 The name comes from the similarity to the exec system call. 2044 2045 It is an ongoing process to be certain the hardware in a machine 2046 is properly shutdown, so do not be surprised if this code does not 2047 initially work for you. As of this writing the exact hardware 2048 interface is strongly in flux, so no good recommendation can be 2049 made. 2050 2051config KEXEC_FILE 2052 bool "kexec file based system call" 2053 select KEXEC_CORE 2054 select BUILD_BIN2C 2055 depends on X86_64 2056 depends on CRYPTO=y 2057 depends on CRYPTO_SHA256=y 2058 ---help--- 2059 This is new version of kexec system call. This system call is 2060 file based and takes file descriptors as system call argument 2061 for kernel and initramfs as opposed to list of segments as 2062 accepted by previous system call. 2063 2064config ARCH_HAS_KEXEC_PURGATORY 2065 def_bool KEXEC_FILE 2066 2067config KEXEC_SIG 2068 bool "Verify kernel signature during kexec_file_load() syscall" 2069 depends on KEXEC_FILE 2070 ---help--- 2071 2072 This option makes the kexec_file_load() syscall check for a valid 2073 signature of the kernel image. The image can still be loaded without 2074 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2075 there's a signature that we can check, then it must be valid. 2076 2077 In addition to this option, you need to enable signature 2078 verification for the corresponding kernel image type being 2079 loaded in order for this to work. 2080 2081config KEXEC_SIG_FORCE 2082 bool "Require a valid signature in kexec_file_load() syscall" 2083 depends on KEXEC_SIG 2084 ---help--- 2085 This option makes kernel signature verification mandatory for 2086 the kexec_file_load() syscall. 2087 2088config KEXEC_BZIMAGE_VERIFY_SIG 2089 bool "Enable bzImage signature verification support" 2090 depends on KEXEC_SIG 2091 depends on SIGNED_PE_FILE_VERIFICATION 2092 select SYSTEM_TRUSTED_KEYRING 2093 ---help--- 2094 Enable bzImage signature verification support. 2095 2096config CRASH_DUMP 2097 bool "kernel crash dumps" 2098 depends on X86_64 || (X86_32 && HIGHMEM) 2099 ---help--- 2100 Generate crash dump after being started by kexec. 2101 This should be normally only set in special crash dump kernels 2102 which are loaded in the main kernel with kexec-tools into 2103 a specially reserved region and then later executed after 2104 a crash by kdump/kexec. The crash dump kernel must be compiled 2105 to a memory address not used by the main kernel or BIOS using 2106 PHYSICAL_START, or it must be built as a relocatable image 2107 (CONFIG_RELOCATABLE=y). 2108 For more details see Documentation/admin-guide/kdump/kdump.rst 2109 2110config KEXEC_JUMP 2111 bool "kexec jump" 2112 depends on KEXEC && HIBERNATION 2113 ---help--- 2114 Jump between original kernel and kexeced kernel and invoke 2115 code in physical address mode via KEXEC 2116 2117config PHYSICAL_START 2118 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2119 default "0x1000000" 2120 ---help--- 2121 This gives the physical address where the kernel is loaded. 2122 2123 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2124 bzImage will decompress itself to above physical address and 2125 run from there. Otherwise, bzImage will run from the address where 2126 it has been loaded by the boot loader and will ignore above physical 2127 address. 2128 2129 In normal kdump cases one does not have to set/change this option 2130 as now bzImage can be compiled as a completely relocatable image 2131 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2132 address. This option is mainly useful for the folks who don't want 2133 to use a bzImage for capturing the crash dump and want to use a 2134 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2135 to be specifically compiled to run from a specific memory area 2136 (normally a reserved region) and this option comes handy. 2137 2138 So if you are using bzImage for capturing the crash dump, 2139 leave the value here unchanged to 0x1000000 and set 2140 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2141 for capturing the crash dump change this value to start of 2142 the reserved region. In other words, it can be set based on 2143 the "X" value as specified in the "crashkernel=YM@XM" 2144 command line boot parameter passed to the panic-ed 2145 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2146 for more details about crash dumps. 2147 2148 Usage of bzImage for capturing the crash dump is recommended as 2149 one does not have to build two kernels. Same kernel can be used 2150 as production kernel and capture kernel. Above option should have 2151 gone away after relocatable bzImage support is introduced. But it 2152 is present because there are users out there who continue to use 2153 vmlinux for dump capture. This option should go away down the 2154 line. 2155 2156 Don't change this unless you know what you are doing. 2157 2158config RELOCATABLE 2159 bool "Build a relocatable kernel" 2160 default y 2161 ---help--- 2162 This builds a kernel image that retains relocation information 2163 so it can be loaded someplace besides the default 1MB. 2164 The relocations tend to make the kernel binary about 10% larger, 2165 but are discarded at runtime. 2166 2167 One use is for the kexec on panic case where the recovery kernel 2168 must live at a different physical address than the primary 2169 kernel. 2170 2171 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2172 it has been loaded at and the compile time physical address 2173 (CONFIG_PHYSICAL_START) is used as the minimum location. 2174 2175config RANDOMIZE_BASE 2176 bool "Randomize the address of the kernel image (KASLR)" 2177 depends on RELOCATABLE 2178 default y 2179 ---help--- 2180 In support of Kernel Address Space Layout Randomization (KASLR), 2181 this randomizes the physical address at which the kernel image 2182 is decompressed and the virtual address where the kernel 2183 image is mapped, as a security feature that deters exploit 2184 attempts relying on knowledge of the location of kernel 2185 code internals. 2186 2187 On 64-bit, the kernel physical and virtual addresses are 2188 randomized separately. The physical address will be anywhere 2189 between 16MB and the top of physical memory (up to 64TB). The 2190 virtual address will be randomized from 16MB up to 1GB (9 bits 2191 of entropy). Note that this also reduces the memory space 2192 available to kernel modules from 1.5GB to 1GB. 2193 2194 On 32-bit, the kernel physical and virtual addresses are 2195 randomized together. They will be randomized from 16MB up to 2196 512MB (8 bits of entropy). 2197 2198 Entropy is generated using the RDRAND instruction if it is 2199 supported. If RDTSC is supported, its value is mixed into 2200 the entropy pool as well. If neither RDRAND nor RDTSC are 2201 supported, then entropy is read from the i8254 timer. The 2202 usable entropy is limited by the kernel being built using 2203 2GB addressing, and that PHYSICAL_ALIGN must be at a 2204 minimum of 2MB. As a result, only 10 bits of entropy are 2205 theoretically possible, but the implementations are further 2206 limited due to memory layouts. 2207 2208 If unsure, say Y. 2209 2210# Relocation on x86 needs some additional build support 2211config X86_NEED_RELOCS 2212 def_bool y 2213 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2214 2215config PHYSICAL_ALIGN 2216 hex "Alignment value to which kernel should be aligned" 2217 default "0x200000" 2218 range 0x2000 0x1000000 if X86_32 2219 range 0x200000 0x1000000 if X86_64 2220 ---help--- 2221 This value puts the alignment restrictions on physical address 2222 where kernel is loaded and run from. Kernel is compiled for an 2223 address which meets above alignment restriction. 2224 2225 If bootloader loads the kernel at a non-aligned address and 2226 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2227 address aligned to above value and run from there. 2228 2229 If bootloader loads the kernel at a non-aligned address and 2230 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2231 load address and decompress itself to the address it has been 2232 compiled for and run from there. The address for which kernel is 2233 compiled already meets above alignment restrictions. Hence the 2234 end result is that kernel runs from a physical address meeting 2235 above alignment restrictions. 2236 2237 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2238 this value must be a multiple of 0x200000. 2239 2240 Don't change this unless you know what you are doing. 2241 2242config DYNAMIC_MEMORY_LAYOUT 2243 bool 2244 ---help--- 2245 This option makes base addresses of vmalloc and vmemmap as well as 2246 __PAGE_OFFSET movable during boot. 2247 2248config RANDOMIZE_MEMORY 2249 bool "Randomize the kernel memory sections" 2250 depends on X86_64 2251 depends on RANDOMIZE_BASE 2252 select DYNAMIC_MEMORY_LAYOUT 2253 default RANDOMIZE_BASE 2254 ---help--- 2255 Randomizes the base virtual address of kernel memory sections 2256 (physical memory mapping, vmalloc & vmemmap). This security feature 2257 makes exploits relying on predictable memory locations less reliable. 2258 2259 The order of allocations remains unchanged. Entropy is generated in 2260 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2261 configuration have in average 30,000 different possible virtual 2262 addresses for each memory section. 2263 2264 If unsure, say Y. 2265 2266config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2267 hex "Physical memory mapping padding" if EXPERT 2268 depends on RANDOMIZE_MEMORY 2269 default "0xa" if MEMORY_HOTPLUG 2270 default "0x0" 2271 range 0x1 0x40 if MEMORY_HOTPLUG 2272 range 0x0 0x40 2273 ---help--- 2274 Define the padding in terabytes added to the existing physical 2275 memory size during kernel memory randomization. It is useful 2276 for memory hotplug support but reduces the entropy available for 2277 address randomization. 2278 2279 If unsure, leave at the default value. 2280 2281config HOTPLUG_CPU 2282 def_bool y 2283 depends on SMP 2284 2285config BOOTPARAM_HOTPLUG_CPU0 2286 bool "Set default setting of cpu0_hotpluggable" 2287 depends on HOTPLUG_CPU 2288 ---help--- 2289 Set whether default state of cpu0_hotpluggable is on or off. 2290 2291 Say Y here to enable CPU0 hotplug by default. If this switch 2292 is turned on, there is no need to give cpu0_hotplug kernel 2293 parameter and the CPU0 hotplug feature is enabled by default. 2294 2295 Please note: there are two known CPU0 dependencies if you want 2296 to enable the CPU0 hotplug feature either by this switch or by 2297 cpu0_hotplug kernel parameter. 2298 2299 First, resume from hibernate or suspend always starts from CPU0. 2300 So hibernate and suspend are prevented if CPU0 is offline. 2301 2302 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2303 offline if any interrupt can not migrate out of CPU0. There may 2304 be other CPU0 dependencies. 2305 2306 Please make sure the dependencies are under your control before 2307 you enable this feature. 2308 2309 Say N if you don't want to enable CPU0 hotplug feature by default. 2310 You still can enable the CPU0 hotplug feature at boot by kernel 2311 parameter cpu0_hotplug. 2312 2313config DEBUG_HOTPLUG_CPU0 2314 def_bool n 2315 prompt "Debug CPU0 hotplug" 2316 depends on HOTPLUG_CPU 2317 ---help--- 2318 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2319 soon as possible and boots up userspace with CPU0 offlined. User 2320 can online CPU0 back after boot time. 2321 2322 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2323 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2324 compilation or giving cpu0_hotplug kernel parameter at boot. 2325 2326 If unsure, say N. 2327 2328config COMPAT_VDSO 2329 def_bool n 2330 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2331 depends on COMPAT_32 2332 ---help--- 2333 Certain buggy versions of glibc will crash if they are 2334 presented with a 32-bit vDSO that is not mapped at the address 2335 indicated in its segment table. 2336 2337 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2338 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2339 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2340 the only released version with the bug, but OpenSUSE 9 2341 contains a buggy "glibc 2.3.2". 2342 2343 The symptom of the bug is that everything crashes on startup, saying: 2344 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2345 2346 Saying Y here changes the default value of the vdso32 boot 2347 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2348 This works around the glibc bug but hurts performance. 2349 2350 If unsure, say N: if you are compiling your own kernel, you 2351 are unlikely to be using a buggy version of glibc. 2352 2353choice 2354 prompt "vsyscall table for legacy applications" 2355 depends on X86_64 2356 default LEGACY_VSYSCALL_XONLY 2357 help 2358 Legacy user code that does not know how to find the vDSO expects 2359 to be able to issue three syscalls by calling fixed addresses in 2360 kernel space. Since this location is not randomized with ASLR, 2361 it can be used to assist security vulnerability exploitation. 2362 2363 This setting can be changed at boot time via the kernel command 2364 line parameter vsyscall=[emulate|xonly|none]. 2365 2366 On a system with recent enough glibc (2.14 or newer) and no 2367 static binaries, you can say None without a performance penalty 2368 to improve security. 2369 2370 If unsure, select "Emulate execution only". 2371 2372 config LEGACY_VSYSCALL_EMULATE 2373 bool "Full emulation" 2374 help 2375 The kernel traps and emulates calls into the fixed vsyscall 2376 address mapping. This makes the mapping non-executable, but 2377 it still contains readable known contents, which could be 2378 used in certain rare security vulnerability exploits. This 2379 configuration is recommended when using legacy userspace 2380 that still uses vsyscalls along with legacy binary 2381 instrumentation tools that require code to be readable. 2382 2383 An example of this type of legacy userspace is running 2384 Pin on an old binary that still uses vsyscalls. 2385 2386 config LEGACY_VSYSCALL_XONLY 2387 bool "Emulate execution only" 2388 help 2389 The kernel traps and emulates calls into the fixed vsyscall 2390 address mapping and does not allow reads. This 2391 configuration is recommended when userspace might use the 2392 legacy vsyscall area but support for legacy binary 2393 instrumentation of legacy code is not needed. It mitigates 2394 certain uses of the vsyscall area as an ASLR-bypassing 2395 buffer. 2396 2397 config LEGACY_VSYSCALL_NONE 2398 bool "None" 2399 help 2400 There will be no vsyscall mapping at all. This will 2401 eliminate any risk of ASLR bypass due to the vsyscall 2402 fixed address mapping. Attempts to use the vsyscalls 2403 will be reported to dmesg, so that either old or 2404 malicious userspace programs can be identified. 2405 2406endchoice 2407 2408config CMDLINE_BOOL 2409 bool "Built-in kernel command line" 2410 ---help--- 2411 Allow for specifying boot arguments to the kernel at 2412 build time. On some systems (e.g. embedded ones), it is 2413 necessary or convenient to provide some or all of the 2414 kernel boot arguments with the kernel itself (that is, 2415 to not rely on the boot loader to provide them.) 2416 2417 To compile command line arguments into the kernel, 2418 set this option to 'Y', then fill in the 2419 boot arguments in CONFIG_CMDLINE. 2420 2421 Systems with fully functional boot loaders (i.e. non-embedded) 2422 should leave this option set to 'N'. 2423 2424config CMDLINE 2425 string "Built-in kernel command string" 2426 depends on CMDLINE_BOOL 2427 default "" 2428 ---help--- 2429 Enter arguments here that should be compiled into the kernel 2430 image and used at boot time. If the boot loader provides a 2431 command line at boot time, it is appended to this string to 2432 form the full kernel command line, when the system boots. 2433 2434 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2435 change this behavior. 2436 2437 In most cases, the command line (whether built-in or provided 2438 by the boot loader) should specify the device for the root 2439 file system. 2440 2441config CMDLINE_OVERRIDE 2442 bool "Built-in command line overrides boot loader arguments" 2443 depends on CMDLINE_BOOL 2444 ---help--- 2445 Set this option to 'Y' to have the kernel ignore the boot loader 2446 command line, and use ONLY the built-in command line. 2447 2448 This is used to work around broken boot loaders. This should 2449 be set to 'N' under normal conditions. 2450 2451config MODIFY_LDT_SYSCALL 2452 bool "Enable the LDT (local descriptor table)" if EXPERT 2453 default y 2454 ---help--- 2455 Linux can allow user programs to install a per-process x86 2456 Local Descriptor Table (LDT) using the modify_ldt(2) system 2457 call. This is required to run 16-bit or segmented code such as 2458 DOSEMU or some Wine programs. It is also used by some very old 2459 threading libraries. 2460 2461 Enabling this feature adds a small amount of overhead to 2462 context switches and increases the low-level kernel attack 2463 surface. Disabling it removes the modify_ldt(2) system call. 2464 2465 Saying 'N' here may make sense for embedded or server kernels. 2466 2467source "kernel/livepatch/Kconfig" 2468 2469endmenu 2470 2471config ARCH_HAS_ADD_PAGES 2472 def_bool y 2473 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2474 2475config ARCH_ENABLE_MEMORY_HOTPLUG 2476 def_bool y 2477 depends on X86_64 || (X86_32 && HIGHMEM) 2478 2479config ARCH_ENABLE_MEMORY_HOTREMOVE 2480 def_bool y 2481 depends on MEMORY_HOTPLUG 2482 2483config USE_PERCPU_NUMA_NODE_ID 2484 def_bool y 2485 depends on NUMA 2486 2487config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2488 def_bool y 2489 depends on X86_64 || X86_PAE 2490 2491config ARCH_ENABLE_HUGEPAGE_MIGRATION 2492 def_bool y 2493 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2494 2495config ARCH_ENABLE_THP_MIGRATION 2496 def_bool y 2497 depends on X86_64 && TRANSPARENT_HUGEPAGE 2498 2499menu "Power management and ACPI options" 2500 2501config ARCH_HIBERNATION_HEADER 2502 def_bool y 2503 depends on HIBERNATION 2504 2505source "kernel/power/Kconfig" 2506 2507source "drivers/acpi/Kconfig" 2508 2509source "drivers/sfi/Kconfig" 2510 2511config X86_APM_BOOT 2512 def_bool y 2513 depends on APM 2514 2515menuconfig APM 2516 tristate "APM (Advanced Power Management) BIOS support" 2517 depends on X86_32 && PM_SLEEP 2518 ---help--- 2519 APM is a BIOS specification for saving power using several different 2520 techniques. This is mostly useful for battery powered laptops with 2521 APM compliant BIOSes. If you say Y here, the system time will be 2522 reset after a RESUME operation, the /proc/apm device will provide 2523 battery status information, and user-space programs will receive 2524 notification of APM "events" (e.g. battery status change). 2525 2526 If you select "Y" here, you can disable actual use of the APM 2527 BIOS by passing the "apm=off" option to the kernel at boot time. 2528 2529 Note that the APM support is almost completely disabled for 2530 machines with more than one CPU. 2531 2532 In order to use APM, you will need supporting software. For location 2533 and more information, read <file:Documentation/power/apm-acpi.rst> 2534 and the Battery Powered Linux mini-HOWTO, available from 2535 <http://www.tldp.org/docs.html#howto>. 2536 2537 This driver does not spin down disk drives (see the hdparm(8) 2538 manpage ("man 8 hdparm") for that), and it doesn't turn off 2539 VESA-compliant "green" monitors. 2540 2541 This driver does not support the TI 4000M TravelMate and the ACER 2542 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2543 desktop machines also don't have compliant BIOSes, and this driver 2544 may cause those machines to panic during the boot phase. 2545 2546 Generally, if you don't have a battery in your machine, there isn't 2547 much point in using this driver and you should say N. If you get 2548 random kernel OOPSes or reboots that don't seem to be related to 2549 anything, try disabling/enabling this option (or disabling/enabling 2550 APM in your BIOS). 2551 2552 Some other things you should try when experiencing seemingly random, 2553 "weird" problems: 2554 2555 1) make sure that you have enough swap space and that it is 2556 enabled. 2557 2) pass the "no-hlt" option to the kernel 2558 3) switch on floating point emulation in the kernel and pass 2559 the "no387" option to the kernel 2560 4) pass the "floppy=nodma" option to the kernel 2561 5) pass the "mem=4M" option to the kernel (thereby disabling 2562 all but the first 4 MB of RAM) 2563 6) make sure that the CPU is not over clocked. 2564 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2565 8) disable the cache from your BIOS settings 2566 9) install a fan for the video card or exchange video RAM 2567 10) install a better fan for the CPU 2568 11) exchange RAM chips 2569 12) exchange the motherboard. 2570 2571 To compile this driver as a module, choose M here: the 2572 module will be called apm. 2573 2574if APM 2575 2576config APM_IGNORE_USER_SUSPEND 2577 bool "Ignore USER SUSPEND" 2578 ---help--- 2579 This option will ignore USER SUSPEND requests. On machines with a 2580 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2581 series notebooks, it is necessary to say Y because of a BIOS bug. 2582 2583config APM_DO_ENABLE 2584 bool "Enable PM at boot time" 2585 ---help--- 2586 Enable APM features at boot time. From page 36 of the APM BIOS 2587 specification: "When disabled, the APM BIOS does not automatically 2588 power manage devices, enter the Standby State, enter the Suspend 2589 State, or take power saving steps in response to CPU Idle calls." 2590 This driver will make CPU Idle calls when Linux is idle (unless this 2591 feature is turned off -- see "Do CPU IDLE calls", below). This 2592 should always save battery power, but more complicated APM features 2593 will be dependent on your BIOS implementation. You may need to turn 2594 this option off if your computer hangs at boot time when using APM 2595 support, or if it beeps continuously instead of suspending. Turn 2596 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2597 T400CDT. This is off by default since most machines do fine without 2598 this feature. 2599 2600config APM_CPU_IDLE 2601 depends on CPU_IDLE 2602 bool "Make CPU Idle calls when idle" 2603 ---help--- 2604 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2605 On some machines, this can activate improved power savings, such as 2606 a slowed CPU clock rate, when the machine is idle. These idle calls 2607 are made after the idle loop has run for some length of time (e.g., 2608 333 mS). On some machines, this will cause a hang at boot time or 2609 whenever the CPU becomes idle. (On machines with more than one CPU, 2610 this option does nothing.) 2611 2612config APM_DISPLAY_BLANK 2613 bool "Enable console blanking using APM" 2614 ---help--- 2615 Enable console blanking using the APM. Some laptops can use this to 2616 turn off the LCD backlight when the screen blanker of the Linux 2617 virtual console blanks the screen. Note that this is only used by 2618 the virtual console screen blanker, and won't turn off the backlight 2619 when using the X Window system. This also doesn't have anything to 2620 do with your VESA-compliant power-saving monitor. Further, this 2621 option doesn't work for all laptops -- it might not turn off your 2622 backlight at all, or it might print a lot of errors to the console, 2623 especially if you are using gpm. 2624 2625config APM_ALLOW_INTS 2626 bool "Allow interrupts during APM BIOS calls" 2627 ---help--- 2628 Normally we disable external interrupts while we are making calls to 2629 the APM BIOS as a measure to lessen the effects of a badly behaving 2630 BIOS implementation. The BIOS should reenable interrupts if it 2631 needs to. Unfortunately, some BIOSes do not -- especially those in 2632 many of the newer IBM Thinkpads. If you experience hangs when you 2633 suspend, try setting this to Y. Otherwise, say N. 2634 2635endif # APM 2636 2637source "drivers/cpufreq/Kconfig" 2638 2639source "drivers/cpuidle/Kconfig" 2640 2641source "drivers/idle/Kconfig" 2642 2643endmenu 2644 2645 2646menu "Bus options (PCI etc.)" 2647 2648choice 2649 prompt "PCI access mode" 2650 depends on X86_32 && PCI 2651 default PCI_GOANY 2652 ---help--- 2653 On PCI systems, the BIOS can be used to detect the PCI devices and 2654 determine their configuration. However, some old PCI motherboards 2655 have BIOS bugs and may crash if this is done. Also, some embedded 2656 PCI-based systems don't have any BIOS at all. Linux can also try to 2657 detect the PCI hardware directly without using the BIOS. 2658 2659 With this option, you can specify how Linux should detect the 2660 PCI devices. If you choose "BIOS", the BIOS will be used, 2661 if you choose "Direct", the BIOS won't be used, and if you 2662 choose "MMConfig", then PCI Express MMCONFIG will be used. 2663 If you choose "Any", the kernel will try MMCONFIG, then the 2664 direct access method and falls back to the BIOS if that doesn't 2665 work. If unsure, go with the default, which is "Any". 2666 2667config PCI_GOBIOS 2668 bool "BIOS" 2669 2670config PCI_GOMMCONFIG 2671 bool "MMConfig" 2672 2673config PCI_GODIRECT 2674 bool "Direct" 2675 2676config PCI_GOOLPC 2677 bool "OLPC XO-1" 2678 depends on OLPC 2679 2680config PCI_GOANY 2681 bool "Any" 2682 2683endchoice 2684 2685config PCI_BIOS 2686 def_bool y 2687 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2688 2689# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2690config PCI_DIRECT 2691 def_bool y 2692 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2693 2694config PCI_MMCONFIG 2695 bool "Support mmconfig PCI config space access" if X86_64 2696 default y 2697 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2698 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2699 2700config PCI_OLPC 2701 def_bool y 2702 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2703 2704config PCI_XEN 2705 def_bool y 2706 depends on PCI && XEN 2707 select SWIOTLB_XEN 2708 2709config MMCONF_FAM10H 2710 def_bool y 2711 depends on X86_64 && PCI_MMCONFIG && ACPI 2712 2713config PCI_CNB20LE_QUIRK 2714 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2715 depends on PCI 2716 help 2717 Read the PCI windows out of the CNB20LE host bridge. This allows 2718 PCI hotplug to work on systems with the CNB20LE chipset which do 2719 not have ACPI. 2720 2721 There's no public spec for this chipset, and this functionality 2722 is known to be incomplete. 2723 2724 You should say N unless you know you need this. 2725 2726config ISA_BUS 2727 bool "ISA bus support on modern systems" if EXPERT 2728 help 2729 Expose ISA bus device drivers and options available for selection and 2730 configuration. Enable this option if your target machine has an ISA 2731 bus. ISA is an older system, displaced by PCI and newer bus 2732 architectures -- if your target machine is modern, it probably does 2733 not have an ISA bus. 2734 2735 If unsure, say N. 2736 2737# x86_64 have no ISA slots, but can have ISA-style DMA. 2738config ISA_DMA_API 2739 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2740 default y 2741 help 2742 Enables ISA-style DMA support for devices requiring such controllers. 2743 If unsure, say Y. 2744 2745if X86_32 2746 2747config ISA 2748 bool "ISA support" 2749 ---help--- 2750 Find out whether you have ISA slots on your motherboard. ISA is the 2751 name of a bus system, i.e. the way the CPU talks to the other stuff 2752 inside your box. Other bus systems are PCI, EISA, MicroChannel 2753 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2754 newer boards don't support it. If you have ISA, say Y, otherwise N. 2755 2756config SCx200 2757 tristate "NatSemi SCx200 support" 2758 ---help--- 2759 This provides basic support for National Semiconductor's 2760 (now AMD's) Geode processors. The driver probes for the 2761 PCI-IDs of several on-chip devices, so its a good dependency 2762 for other scx200_* drivers. 2763 2764 If compiled as a module, the driver is named scx200. 2765 2766config SCx200HR_TIMER 2767 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2768 depends on SCx200 2769 default y 2770 ---help--- 2771 This driver provides a clocksource built upon the on-chip 2772 27MHz high-resolution timer. Its also a workaround for 2773 NSC Geode SC-1100's buggy TSC, which loses time when the 2774 processor goes idle (as is done by the scheduler). The 2775 other workaround is idle=poll boot option. 2776 2777config OLPC 2778 bool "One Laptop Per Child support" 2779 depends on !X86_PAE 2780 select GPIOLIB 2781 select OF 2782 select OF_PROMTREE 2783 select IRQ_DOMAIN 2784 select OLPC_EC 2785 ---help--- 2786 Add support for detecting the unique features of the OLPC 2787 XO hardware. 2788 2789config OLPC_XO1_PM 2790 bool "OLPC XO-1 Power Management" 2791 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2792 ---help--- 2793 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2794 2795config OLPC_XO1_RTC 2796 bool "OLPC XO-1 Real Time Clock" 2797 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2798 ---help--- 2799 Add support for the XO-1 real time clock, which can be used as a 2800 programmable wakeup source. 2801 2802config OLPC_XO1_SCI 2803 bool "OLPC XO-1 SCI extras" 2804 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2805 depends on INPUT=y 2806 select POWER_SUPPLY 2807 ---help--- 2808 Add support for SCI-based features of the OLPC XO-1 laptop: 2809 - EC-driven system wakeups 2810 - Power button 2811 - Ebook switch 2812 - Lid switch 2813 - AC adapter status updates 2814 - Battery status updates 2815 2816config OLPC_XO15_SCI 2817 bool "OLPC XO-1.5 SCI extras" 2818 depends on OLPC && ACPI 2819 select POWER_SUPPLY 2820 ---help--- 2821 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2822 - EC-driven system wakeups 2823 - AC adapter status updates 2824 - Battery status updates 2825 2826config ALIX 2827 bool "PCEngines ALIX System Support (LED setup)" 2828 select GPIOLIB 2829 ---help--- 2830 This option enables system support for the PCEngines ALIX. 2831 At present this just sets up LEDs for GPIO control on 2832 ALIX2/3/6 boards. However, other system specific setup should 2833 get added here. 2834 2835 Note: You must still enable the drivers for GPIO and LED support 2836 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2837 2838 Note: You have to set alix.force=1 for boards with Award BIOS. 2839 2840config NET5501 2841 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2842 select GPIOLIB 2843 ---help--- 2844 This option enables system support for the Soekris Engineering net5501. 2845 2846config GEOS 2847 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2848 select GPIOLIB 2849 depends on DMI 2850 ---help--- 2851 This option enables system support for the Traverse Technologies GEOS. 2852 2853config TS5500 2854 bool "Technologic Systems TS-5500 platform support" 2855 depends on MELAN 2856 select CHECK_SIGNATURE 2857 select NEW_LEDS 2858 select LEDS_CLASS 2859 ---help--- 2860 This option enables system support for the Technologic Systems TS-5500. 2861 2862endif # X86_32 2863 2864config AMD_NB 2865 def_bool y 2866 depends on CPU_SUP_AMD && PCI 2867 2868config X86_SYSFB 2869 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2870 help 2871 Firmwares often provide initial graphics framebuffers so the BIOS, 2872 bootloader or kernel can show basic video-output during boot for 2873 user-guidance and debugging. Historically, x86 used the VESA BIOS 2874 Extensions and EFI-framebuffers for this, which are mostly limited 2875 to x86. 2876 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2877 framebuffers so the new generic system-framebuffer drivers can be 2878 used on x86. If the framebuffer is not compatible with the generic 2879 modes, it is advertised as fallback platform framebuffer so legacy 2880 drivers like efifb, vesafb and uvesafb can pick it up. 2881 If this option is not selected, all system framebuffers are always 2882 marked as fallback platform framebuffers as usual. 2883 2884 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2885 not be able to pick up generic system framebuffers if this option 2886 is selected. You are highly encouraged to enable simplefb as 2887 replacement if you select this option. simplefb can correctly deal 2888 with generic system framebuffers. But you should still keep vesafb 2889 and others enabled as fallback if a system framebuffer is 2890 incompatible with simplefb. 2891 2892 If unsure, say Y. 2893 2894endmenu 2895 2896 2897menu "Binary Emulations" 2898 2899config IA32_EMULATION 2900 bool "IA32 Emulation" 2901 depends on X86_64 2902 select ARCH_WANT_OLD_COMPAT_IPC 2903 select BINFMT_ELF 2904 select COMPAT_BINFMT_ELF 2905 select COMPAT_OLD_SIGACTION 2906 ---help--- 2907 Include code to run legacy 32-bit programs under a 2908 64-bit kernel. You should likely turn this on, unless you're 2909 100% sure that you don't have any 32-bit programs left. 2910 2911config IA32_AOUT 2912 tristate "IA32 a.out support" 2913 depends on IA32_EMULATION 2914 depends on BROKEN 2915 ---help--- 2916 Support old a.out binaries in the 32bit emulation. 2917 2918config X86_X32 2919 bool "x32 ABI for 64-bit mode" 2920 depends on X86_64 2921 ---help--- 2922 Include code to run binaries for the x32 native 32-bit ABI 2923 for 64-bit processors. An x32 process gets access to the 2924 full 64-bit register file and wide data path while leaving 2925 pointers at 32 bits for smaller memory footprint. 2926 2927 You will need a recent binutils (2.22 or later) with 2928 elf32_x86_64 support enabled to compile a kernel with this 2929 option set. 2930 2931config COMPAT_32 2932 def_bool y 2933 depends on IA32_EMULATION || X86_32 2934 select HAVE_UID16 2935 select OLD_SIGSUSPEND3 2936 2937config COMPAT 2938 def_bool y 2939 depends on IA32_EMULATION || X86_X32 2940 2941if COMPAT 2942config COMPAT_FOR_U64_ALIGNMENT 2943 def_bool y 2944 2945config SYSVIPC_COMPAT 2946 def_bool y 2947 depends on SYSVIPC 2948endif 2949 2950endmenu 2951 2952 2953config HAVE_ATOMIC_IOMAP 2954 def_bool y 2955 depends on X86_32 2956 2957config X86_DEV_DMA_OPS 2958 bool 2959 2960source "drivers/firmware/Kconfig" 2961 2962source "arch/x86/kvm/Kconfig" 2963