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_KASAN_VMALLOC if X86_64 138 select HAVE_ARCH_KGDB 139 select HAVE_ARCH_MMAP_RND_BITS if MMU 140 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 141 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 142 select HAVE_ARCH_PREL32_RELOCATIONS 143 select HAVE_ARCH_SECCOMP_FILTER 144 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 145 select HAVE_ARCH_STACKLEAK 146 select HAVE_ARCH_TRACEHOOK 147 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 148 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 149 select HAVE_ARCH_VMAP_STACK if X86_64 150 select HAVE_ARCH_WITHIN_STACK_FRAMES 151 select HAVE_ASM_MODVERSIONS 152 select HAVE_CMPXCHG_DOUBLE 153 select HAVE_CMPXCHG_LOCAL 154 select HAVE_CONTEXT_TRACKING if X86_64 155 select HAVE_COPY_THREAD_TLS 156 select HAVE_C_RECORDMCOUNT 157 select HAVE_DEBUG_KMEMLEAK 158 select HAVE_DMA_CONTIGUOUS 159 select HAVE_DYNAMIC_FTRACE 160 select HAVE_DYNAMIC_FTRACE_WITH_REGS 161 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 162 select HAVE_EBPF_JIT 163 select HAVE_EFFICIENT_UNALIGNED_ACCESS 164 select HAVE_EISA 165 select HAVE_EXIT_THREAD 166 select HAVE_FAST_GUP 167 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 168 select HAVE_FTRACE_MCOUNT_RECORD 169 select HAVE_FUNCTION_GRAPH_TRACER 170 select HAVE_FUNCTION_TRACER 171 select HAVE_GCC_PLUGINS 172 select HAVE_HW_BREAKPOINT 173 select HAVE_IDE 174 select HAVE_IOREMAP_PROT 175 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 176 select HAVE_IRQ_TIME_ACCOUNTING 177 select HAVE_KERNEL_BZIP2 178 select HAVE_KERNEL_GZIP 179 select HAVE_KERNEL_LZ4 180 select HAVE_KERNEL_LZMA 181 select HAVE_KERNEL_LZO 182 select HAVE_KERNEL_XZ 183 select HAVE_KPROBES 184 select HAVE_KPROBES_ON_FTRACE 185 select HAVE_FUNCTION_ERROR_INJECTION 186 select HAVE_KRETPROBES 187 select HAVE_KVM 188 select HAVE_LIVEPATCH if X86_64 189 select HAVE_MEMBLOCK_NODE_MAP 190 select HAVE_MIXED_BREAKPOINTS_REGS 191 select HAVE_MOD_ARCH_SPECIFIC 192 select HAVE_MOVE_PMD 193 select HAVE_NMI 194 select HAVE_OPROFILE 195 select HAVE_OPTPROBES 196 select HAVE_PCSPKR_PLATFORM 197 select HAVE_PERF_EVENTS 198 select HAVE_PERF_EVENTS_NMI 199 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 200 select HAVE_PCI 201 select HAVE_PERF_REGS 202 select HAVE_PERF_USER_STACK_DUMP 203 select HAVE_RCU_TABLE_FREE if PARAVIRT 204 select HAVE_REGS_AND_STACK_ACCESS_API 205 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 206 select HAVE_FUNCTION_ARG_ACCESS_API 207 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 208 select HAVE_STACK_VALIDATION if X86_64 209 select HAVE_RSEQ 210 select HAVE_SYSCALL_TRACEPOINTS 211 select HAVE_UNSTABLE_SCHED_CLOCK 212 select HAVE_USER_RETURN_NOTIFIER 213 select HAVE_GENERIC_VDSO 214 select HOTPLUG_SMT if SMP 215 select IRQ_FORCED_THREADING 216 select NEED_SG_DMA_LENGTH 217 select PCI_DOMAINS if PCI 218 select PCI_LOCKLESS_CONFIG if PCI 219 select PERF_EVENTS 220 select RTC_LIB 221 select RTC_MC146818_LIB 222 select SPARSE_IRQ 223 select SRCU 224 select SYSCTL_EXCEPTION_TRACE 225 select THREAD_INFO_IN_TASK 226 select USER_STACKTRACE_SUPPORT 227 select VIRT_TO_BUS 228 select X86_FEATURE_NAMES if PROC_FS 229 select PROC_PID_ARCH_STATUS if PROC_FS 230 231config INSTRUCTION_DECODER 232 def_bool y 233 depends on KPROBES || PERF_EVENTS || UPROBES 234 235config OUTPUT_FORMAT 236 string 237 default "elf32-i386" if X86_32 238 default "elf64-x86-64" if X86_64 239 240config ARCH_DEFCONFIG 241 string 242 default "arch/x86/configs/i386_defconfig" if X86_32 243 default "arch/x86/configs/x86_64_defconfig" if X86_64 244 245config LOCKDEP_SUPPORT 246 def_bool y 247 248config STACKTRACE_SUPPORT 249 def_bool y 250 251config MMU 252 def_bool y 253 254config ARCH_MMAP_RND_BITS_MIN 255 default 28 if 64BIT 256 default 8 257 258config ARCH_MMAP_RND_BITS_MAX 259 default 32 if 64BIT 260 default 16 261 262config ARCH_MMAP_RND_COMPAT_BITS_MIN 263 default 8 264 265config ARCH_MMAP_RND_COMPAT_BITS_MAX 266 default 16 267 268config SBUS 269 bool 270 271config GENERIC_ISA_DMA 272 def_bool y 273 depends on ISA_DMA_API 274 275config GENERIC_BUG 276 def_bool y 277 depends on BUG 278 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 279 280config GENERIC_BUG_RELATIVE_POINTERS 281 bool 282 283config ARCH_MAY_HAVE_PC_FDC 284 def_bool y 285 depends on ISA_DMA_API 286 287config GENERIC_CALIBRATE_DELAY 288 def_bool y 289 290config ARCH_HAS_CPU_RELAX 291 def_bool y 292 293config ARCH_HAS_CACHE_LINE_SIZE 294 def_bool y 295 296config ARCH_HAS_FILTER_PGPROT 297 def_bool y 298 299config HAVE_SETUP_PER_CPU_AREA 300 def_bool y 301 302config NEED_PER_CPU_EMBED_FIRST_CHUNK 303 def_bool y 304 305config NEED_PER_CPU_PAGE_FIRST_CHUNK 306 def_bool y 307 308config ARCH_HIBERNATION_POSSIBLE 309 def_bool y 310 311config ARCH_SUSPEND_POSSIBLE 312 def_bool y 313 314config ARCH_WANT_GENERAL_HUGETLB 315 def_bool y 316 317config ZONE_DMA32 318 def_bool y if X86_64 319 320config AUDIT_ARCH 321 def_bool y if X86_64 322 323config ARCH_SUPPORTS_DEBUG_PAGEALLOC 324 def_bool y 325 326config KASAN_SHADOW_OFFSET 327 hex 328 depends on KASAN 329 default 0xdffffc0000000000 330 331config HAVE_INTEL_TXT 332 def_bool y 333 depends on INTEL_IOMMU && ACPI 334 335config X86_32_SMP 336 def_bool y 337 depends on X86_32 && SMP 338 339config X86_64_SMP 340 def_bool y 341 depends on X86_64 && SMP 342 343config X86_32_LAZY_GS 344 def_bool y 345 depends on X86_32 && !STACKPROTECTOR 346 347config ARCH_SUPPORTS_UPROBES 348 def_bool y 349 350config FIX_EARLYCON_MEM 351 def_bool y 352 353config DYNAMIC_PHYSICAL_MASK 354 bool 355 356config PGTABLE_LEVELS 357 int 358 default 5 if X86_5LEVEL 359 default 4 if X86_64 360 default 3 if X86_PAE 361 default 2 362 363config CC_HAS_SANE_STACKPROTECTOR 364 bool 365 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 366 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 367 help 368 We have to make sure stack protector is unconditionally disabled if 369 the compiler produces broken code. 370 371menu "Processor type and features" 372 373config ZONE_DMA 374 bool "DMA memory allocation support" if EXPERT 375 default y 376 help 377 DMA memory allocation support allows devices with less than 32-bit 378 addressing to allocate within the first 16MB of address space. 379 Disable if no such devices will be used. 380 381 If unsure, say Y. 382 383config SMP 384 bool "Symmetric multi-processing support" 385 ---help--- 386 This enables support for systems with more than one CPU. If you have 387 a system with only one CPU, say N. If you have a system with more 388 than one CPU, say Y. 389 390 If you say N here, the kernel will run on uni- and multiprocessor 391 machines, but will use only one CPU of a multiprocessor machine. If 392 you say Y here, the kernel will run on many, but not all, 393 uniprocessor machines. On a uniprocessor machine, the kernel 394 will run faster if you say N here. 395 396 Note that if you say Y here and choose architecture "586" or 397 "Pentium" under "Processor family", the kernel will not work on 486 398 architectures. Similarly, multiprocessor kernels for the "PPro" 399 architecture may not work on all Pentium based boards. 400 401 People using multiprocessor machines who say Y here should also say 402 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 403 Management" code will be disabled if you say Y here. 404 405 See also <file:Documentation/x86/i386/IO-APIC.rst>, 406 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 407 <http://www.tldp.org/docs.html#howto>. 408 409 If you don't know what to do here, say N. 410 411config X86_FEATURE_NAMES 412 bool "Processor feature human-readable names" if EMBEDDED 413 default y 414 ---help--- 415 This option compiles in a table of x86 feature bits and corresponding 416 names. This is required to support /proc/cpuinfo and a few kernel 417 messages. You can disable this to save space, at the expense of 418 making those few kernel messages show numeric feature bits instead. 419 420 If in doubt, say Y. 421 422config X86_X2APIC 423 bool "Support x2apic" 424 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 425 ---help--- 426 This enables x2apic support on CPUs that have this feature. 427 428 This allows 32-bit apic IDs (so it can support very large systems), 429 and accesses the local apic via MSRs not via mmio. 430 431 If you don't know what to do here, say N. 432 433config X86_MPPARSE 434 bool "Enable MPS table" if ACPI || SFI 435 default y 436 depends on X86_LOCAL_APIC 437 ---help--- 438 For old smp systems that do not have proper acpi support. Newer systems 439 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 440 441config GOLDFISH 442 def_bool y 443 depends on X86_GOLDFISH 444 445config RETPOLINE 446 bool "Avoid speculative indirect branches in kernel" 447 default y 448 select STACK_VALIDATION if HAVE_STACK_VALIDATION 449 help 450 Compile kernel with the retpoline compiler options to guard against 451 kernel-to-user data leaks by avoiding speculative indirect 452 branches. Requires a compiler with -mindirect-branch=thunk-extern 453 support for full protection. The kernel may run slower. 454 455config X86_CPU_RESCTRL 456 bool "x86 CPU resource control support" 457 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 458 select KERNFS 459 help 460 Enable x86 CPU resource control support. 461 462 Provide support for the allocation and monitoring of system resources 463 usage by the CPU. 464 465 Intel calls this Intel Resource Director Technology 466 (Intel(R) RDT). More information about RDT can be found in the 467 Intel x86 Architecture Software Developer Manual. 468 469 AMD calls this AMD Platform Quality of Service (AMD QoS). 470 More information about AMD QoS can be found in the AMD64 Technology 471 Platform Quality of Service Extensions manual. 472 473 Say N if unsure. 474 475if X86_32 476config X86_BIGSMP 477 bool "Support for big SMP systems with more than 8 CPUs" 478 depends on SMP 479 ---help--- 480 This option is needed for the systems that have more than 8 CPUs 481 482config X86_EXTENDED_PLATFORM 483 bool "Support for extended (non-PC) x86 platforms" 484 default y 485 ---help--- 486 If you disable this option then the kernel will only support 487 standard PC platforms. (which covers the vast majority of 488 systems out there.) 489 490 If you enable this option then you'll be able to select support 491 for the following (non-PC) 32 bit x86 platforms: 492 Goldfish (Android emulator) 493 AMD Elan 494 RDC R-321x SoC 495 SGI 320/540 (Visual Workstation) 496 STA2X11-based (e.g. Northville) 497 Moorestown MID devices 498 499 If you have one of these systems, or if you want to build a 500 generic distribution kernel, say Y here - otherwise say N. 501endif 502 503if X86_64 504config X86_EXTENDED_PLATFORM 505 bool "Support for extended (non-PC) x86 platforms" 506 default y 507 ---help--- 508 If you disable this option then the kernel will only support 509 standard PC platforms. (which covers the vast majority of 510 systems out there.) 511 512 If you enable this option then you'll be able to select support 513 for the following (non-PC) 64 bit x86 platforms: 514 Numascale NumaChip 515 ScaleMP vSMP 516 SGI Ultraviolet 517 518 If you have one of these systems, or if you want to build a 519 generic distribution kernel, say Y here - otherwise say N. 520endif 521# This is an alphabetically sorted list of 64 bit extended platforms 522# Please maintain the alphabetic order if and when there are additions 523config X86_NUMACHIP 524 bool "Numascale NumaChip" 525 depends on X86_64 526 depends on X86_EXTENDED_PLATFORM 527 depends on NUMA 528 depends on SMP 529 depends on X86_X2APIC 530 depends on PCI_MMCONFIG 531 ---help--- 532 Adds support for Numascale NumaChip large-SMP systems. Needed to 533 enable more than ~168 cores. 534 If you don't have one of these, you should say N here. 535 536config X86_VSMP 537 bool "ScaleMP vSMP" 538 select HYPERVISOR_GUEST 539 select PARAVIRT 540 depends on X86_64 && PCI 541 depends on X86_EXTENDED_PLATFORM 542 depends on SMP 543 ---help--- 544 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 545 supposed to run on these EM64T-based machines. Only choose this option 546 if you have one of these machines. 547 548config X86_UV 549 bool "SGI Ultraviolet" 550 depends on X86_64 551 depends on X86_EXTENDED_PLATFORM 552 depends on NUMA 553 depends on EFI 554 depends on X86_X2APIC 555 depends on PCI 556 ---help--- 557 This option is needed in order to support SGI Ultraviolet systems. 558 If you don't have one of these, you should say N here. 559 560# Following is an alphabetically sorted list of 32 bit extended platforms 561# Please maintain the alphabetic order if and when there are additions 562 563config X86_GOLDFISH 564 bool "Goldfish (Virtual Platform)" 565 depends on X86_EXTENDED_PLATFORM 566 ---help--- 567 Enable support for the Goldfish virtual platform used primarily 568 for Android development. Unless you are building for the Android 569 Goldfish emulator say N here. 570 571config X86_INTEL_CE 572 bool "CE4100 TV platform" 573 depends on PCI 574 depends on PCI_GODIRECT 575 depends on X86_IO_APIC 576 depends on X86_32 577 depends on X86_EXTENDED_PLATFORM 578 select X86_REBOOTFIXUPS 579 select OF 580 select OF_EARLY_FLATTREE 581 ---help--- 582 Select for the Intel CE media processor (CE4100) SOC. 583 This option compiles in support for the CE4100 SOC for settop 584 boxes and media devices. 585 586config X86_INTEL_MID 587 bool "Intel MID platform support" 588 depends on X86_EXTENDED_PLATFORM 589 depends on X86_PLATFORM_DEVICES 590 depends on PCI 591 depends on X86_64 || (PCI_GOANY && X86_32) 592 depends on X86_IO_APIC 593 select SFI 594 select I2C 595 select DW_APB_TIMER 596 select APB_TIMER 597 select INTEL_SCU_IPC 598 select MFD_INTEL_MSIC 599 ---help--- 600 Select to build a kernel capable of supporting Intel MID (Mobile 601 Internet Device) platform systems which do not have the PCI legacy 602 interfaces. If you are building for a PC class system say N here. 603 604 Intel MID platforms are based on an Intel processor and chipset which 605 consume less power than most of the x86 derivatives. 606 607config X86_INTEL_QUARK 608 bool "Intel Quark platform support" 609 depends on X86_32 610 depends on X86_EXTENDED_PLATFORM 611 depends on X86_PLATFORM_DEVICES 612 depends on X86_TSC 613 depends on PCI 614 depends on PCI_GOANY 615 depends on X86_IO_APIC 616 select IOSF_MBI 617 select INTEL_IMR 618 select COMMON_CLK 619 ---help--- 620 Select to include support for Quark X1000 SoC. 621 Say Y here if you have a Quark based system such as the Arduino 622 compatible Intel Galileo. 623 624config X86_INTEL_LPSS 625 bool "Intel Low Power Subsystem Support" 626 depends on X86 && ACPI && PCI 627 select COMMON_CLK 628 select PINCTRL 629 select IOSF_MBI 630 ---help--- 631 Select to build support for Intel Low Power Subsystem such as 632 found on Intel Lynxpoint PCH. Selecting this option enables 633 things like clock tree (common clock framework) and pincontrol 634 which are needed by the LPSS peripheral drivers. 635 636config X86_AMD_PLATFORM_DEVICE 637 bool "AMD ACPI2Platform devices support" 638 depends on ACPI 639 select COMMON_CLK 640 select PINCTRL 641 ---help--- 642 Select to interpret AMD specific ACPI device to platform device 643 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 644 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 645 implemented under PINCTRL subsystem. 646 647config IOSF_MBI 648 tristate "Intel SoC IOSF Sideband support for SoC platforms" 649 depends on PCI 650 ---help--- 651 This option enables sideband register access support for Intel SoC 652 platforms. On these platforms the IOSF sideband is used in lieu of 653 MSR's for some register accesses, mostly but not limited to thermal 654 and power. Drivers may query the availability of this device to 655 determine if they need the sideband in order to work on these 656 platforms. The sideband is available on the following SoC products. 657 This list is not meant to be exclusive. 658 - BayTrail 659 - Braswell 660 - Quark 661 662 You should say Y if you are running a kernel on one of these SoC's. 663 664config IOSF_MBI_DEBUG 665 bool "Enable IOSF sideband access through debugfs" 666 depends on IOSF_MBI && DEBUG_FS 667 ---help--- 668 Select this option to expose the IOSF sideband access registers (MCR, 669 MDR, MCRX) through debugfs to write and read register information from 670 different units on the SoC. This is most useful for obtaining device 671 state information for debug and analysis. As this is a general access 672 mechanism, users of this option would have specific knowledge of the 673 device they want to access. 674 675 If you don't require the option or are in doubt, say N. 676 677config X86_RDC321X 678 bool "RDC R-321x SoC" 679 depends on X86_32 680 depends on X86_EXTENDED_PLATFORM 681 select M486 682 select X86_REBOOTFIXUPS 683 ---help--- 684 This option is needed for RDC R-321x system-on-chip, also known 685 as R-8610-(G). 686 If you don't have one of these chips, you should say N here. 687 688config X86_32_NON_STANDARD 689 bool "Support non-standard 32-bit SMP architectures" 690 depends on X86_32 && SMP 691 depends on X86_EXTENDED_PLATFORM 692 ---help--- 693 This option compiles in the bigsmp and STA2X11 default 694 subarchitectures. It is intended for a generic binary 695 kernel. If you select them all, kernel will probe it one by 696 one and will fallback to default. 697 698# Alphabetically sorted list of Non standard 32 bit platforms 699 700config X86_SUPPORTS_MEMORY_FAILURE 701 def_bool y 702 # MCE code calls memory_failure(): 703 depends on X86_MCE 704 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 705 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 706 depends on X86_64 || !SPARSEMEM 707 select ARCH_SUPPORTS_MEMORY_FAILURE 708 709config STA2X11 710 bool "STA2X11 Companion Chip Support" 711 depends on X86_32_NON_STANDARD && PCI 712 select SWIOTLB 713 select MFD_STA2X11 714 select GPIOLIB 715 ---help--- 716 This adds support for boards based on the STA2X11 IO-Hub, 717 a.k.a. "ConneXt". The chip is used in place of the standard 718 PC chipset, so all "standard" peripherals are missing. If this 719 option is selected the kernel will still be able to boot on 720 standard PC machines. 721 722config X86_32_IRIS 723 tristate "Eurobraille/Iris poweroff module" 724 depends on X86_32 725 ---help--- 726 The Iris machines from EuroBraille do not have APM or ACPI support 727 to shut themselves down properly. A special I/O sequence is 728 needed to do so, which is what this module does at 729 kernel shutdown. 730 731 This is only for Iris machines from EuroBraille. 732 733 If unused, say N. 734 735config SCHED_OMIT_FRAME_POINTER 736 def_bool y 737 prompt "Single-depth WCHAN output" 738 depends on X86 739 ---help--- 740 Calculate simpler /proc/<PID>/wchan values. If this option 741 is disabled then wchan values will recurse back to the 742 caller function. This provides more accurate wchan values, 743 at the expense of slightly more scheduling overhead. 744 745 If in doubt, say "Y". 746 747menuconfig HYPERVISOR_GUEST 748 bool "Linux guest support" 749 ---help--- 750 Say Y here to enable options for running Linux under various hyper- 751 visors. This option enables basic hypervisor detection and platform 752 setup. 753 754 If you say N, all options in this submenu will be skipped and 755 disabled, and Linux guest support won't be built in. 756 757if HYPERVISOR_GUEST 758 759config PARAVIRT 760 bool "Enable paravirtualization code" 761 ---help--- 762 This changes the kernel so it can modify itself when it is run 763 under a hypervisor, potentially improving performance significantly 764 over full virtualization. However, when run without a hypervisor 765 the kernel is theoretically slower and slightly larger. 766 767config PARAVIRT_XXL 768 bool 769 770config PARAVIRT_DEBUG 771 bool "paravirt-ops debugging" 772 depends on PARAVIRT && DEBUG_KERNEL 773 ---help--- 774 Enable to debug paravirt_ops internals. Specifically, BUG if 775 a paravirt_op is missing when it is called. 776 777config PARAVIRT_SPINLOCKS 778 bool "Paravirtualization layer for spinlocks" 779 depends on PARAVIRT && SMP 780 ---help--- 781 Paravirtualized spinlocks allow a pvops backend to replace the 782 spinlock implementation with something virtualization-friendly 783 (for example, block the virtual CPU rather than spinning). 784 785 It has a minimal impact on native kernels and gives a nice performance 786 benefit on paravirtualized KVM / Xen kernels. 787 788 If you are unsure how to answer this question, answer Y. 789 790config X86_HV_CALLBACK_VECTOR 791 def_bool n 792 793source "arch/x86/xen/Kconfig" 794 795config KVM_GUEST 796 bool "KVM Guest support (including kvmclock)" 797 depends on PARAVIRT 798 select PARAVIRT_CLOCK 799 select ARCH_CPUIDLE_HALTPOLL 800 default y 801 ---help--- 802 This option enables various optimizations for running under the KVM 803 hypervisor. It includes a paravirtualized clock, so that instead 804 of relying on a PIT (or probably other) emulation by the 805 underlying device model, the host provides the guest with 806 timing infrastructure such as time of day, and system time 807 808config ARCH_CPUIDLE_HALTPOLL 809 def_bool n 810 prompt "Disable host haltpoll when loading haltpoll driver" 811 help 812 If virtualized under KVM, disable host haltpoll. 813 814config PVH 815 bool "Support for running PVH guests" 816 ---help--- 817 This option enables the PVH entry point for guest virtual machines 818 as specified in the x86/HVM direct boot ABI. 819 820config KVM_DEBUG_FS 821 bool "Enable debug information for KVM Guests in debugfs" 822 depends on KVM_GUEST && DEBUG_FS 823 ---help--- 824 This option enables collection of various statistics for KVM guest. 825 Statistics are displayed in debugfs filesystem. Enabling this option 826 may incur significant overhead. 827 828config PARAVIRT_TIME_ACCOUNTING 829 bool "Paravirtual steal time accounting" 830 depends on PARAVIRT 831 ---help--- 832 Select this option to enable fine granularity task steal time 833 accounting. Time spent executing other tasks in parallel with 834 the current vCPU is discounted from the vCPU power. To account for 835 that, there can be a small performance impact. 836 837 If in doubt, say N here. 838 839config PARAVIRT_CLOCK 840 bool 841 842config JAILHOUSE_GUEST 843 bool "Jailhouse non-root cell support" 844 depends on X86_64 && PCI 845 select X86_PM_TIMER 846 ---help--- 847 This option allows to run Linux as guest in a Jailhouse non-root 848 cell. You can leave this option disabled if you only want to start 849 Jailhouse and run Linux afterwards in the root cell. 850 851config ACRN_GUEST 852 bool "ACRN Guest support" 853 depends on X86_64 854 select X86_HV_CALLBACK_VECTOR 855 help 856 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 857 a flexible, lightweight reference open-source hypervisor, built with 858 real-time and safety-criticality in mind. It is built for embedded 859 IOT with small footprint and real-time features. More details can be 860 found in https://projectacrn.org/. 861 862endif #HYPERVISOR_GUEST 863 864source "arch/x86/Kconfig.cpu" 865 866config HPET_TIMER 867 def_bool X86_64 868 prompt "HPET Timer Support" if X86_32 869 ---help--- 870 Use the IA-PC HPET (High Precision Event Timer) to manage 871 time in preference to the PIT and RTC, if a HPET is 872 present. 873 HPET is the next generation timer replacing legacy 8254s. 874 The HPET provides a stable time base on SMP 875 systems, unlike the TSC, but it is more expensive to access, 876 as it is off-chip. The interface used is documented 877 in the HPET spec, revision 1. 878 879 You can safely choose Y here. However, HPET will only be 880 activated if the platform and the BIOS support this feature. 881 Otherwise the 8254 will be used for timing services. 882 883 Choose N to continue using the legacy 8254 timer. 884 885config HPET_EMULATE_RTC 886 def_bool y 887 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 888 889config APB_TIMER 890 def_bool y if X86_INTEL_MID 891 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 892 select DW_APB_TIMER 893 depends on X86_INTEL_MID && SFI 894 help 895 APB timer is the replacement for 8254, HPET on X86 MID platforms. 896 The APBT provides a stable time base on SMP 897 systems, unlike the TSC, but it is more expensive to access, 898 as it is off-chip. APB timers are always running regardless of CPU 899 C states, they are used as per CPU clockevent device when possible. 900 901# Mark as expert because too many people got it wrong. 902# The code disables itself when not needed. 903config DMI 904 default y 905 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 906 bool "Enable DMI scanning" if EXPERT 907 ---help--- 908 Enabled scanning of DMI to identify machine quirks. Say Y 909 here unless you have verified that your setup is not 910 affected by entries in the DMI blacklist. Required by PNP 911 BIOS code. 912 913config GART_IOMMU 914 bool "Old AMD GART IOMMU support" 915 select IOMMU_HELPER 916 select SWIOTLB 917 depends on X86_64 && PCI && AMD_NB 918 ---help--- 919 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 920 GART based hardware IOMMUs. 921 922 The GART supports full DMA access for devices with 32-bit access 923 limitations, on systems with more than 3 GB. This is usually needed 924 for USB, sound, many IDE/SATA chipsets and some other devices. 925 926 Newer systems typically have a modern AMD IOMMU, supported via 927 the CONFIG_AMD_IOMMU=y config option. 928 929 In normal configurations this driver is only active when needed: 930 there's more than 3 GB of memory and the system contains a 931 32-bit limited device. 932 933 If unsure, say Y. 934 935config MAXSMP 936 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 937 depends on X86_64 && SMP && DEBUG_KERNEL 938 select CPUMASK_OFFSTACK 939 ---help--- 940 Enable maximum number of CPUS and NUMA Nodes for this architecture. 941 If unsure, say N. 942 943# 944# The maximum number of CPUs supported: 945# 946# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 947# and which can be configured interactively in the 948# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 949# 950# The ranges are different on 32-bit and 64-bit kernels, depending on 951# hardware capabilities and scalability features of the kernel. 952# 953# ( If MAXSMP is enabled we just use the highest possible value and disable 954# interactive configuration. ) 955# 956 957config NR_CPUS_RANGE_BEGIN 958 int 959 default NR_CPUS_RANGE_END if MAXSMP 960 default 1 if !SMP 961 default 2 962 963config NR_CPUS_RANGE_END 964 int 965 depends on X86_32 966 default 64 if SMP && X86_BIGSMP 967 default 8 if SMP && !X86_BIGSMP 968 default 1 if !SMP 969 970config NR_CPUS_RANGE_END 971 int 972 depends on X86_64 973 default 8192 if SMP && CPUMASK_OFFSTACK 974 default 512 if SMP && !CPUMASK_OFFSTACK 975 default 1 if !SMP 976 977config NR_CPUS_DEFAULT 978 int 979 depends on X86_32 980 default 32 if X86_BIGSMP 981 default 8 if SMP 982 default 1 if !SMP 983 984config NR_CPUS_DEFAULT 985 int 986 depends on X86_64 987 default 8192 if MAXSMP 988 default 64 if SMP 989 default 1 if !SMP 990 991config NR_CPUS 992 int "Maximum number of CPUs" if SMP && !MAXSMP 993 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 994 default NR_CPUS_DEFAULT 995 ---help--- 996 This allows you to specify the maximum number of CPUs which this 997 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 998 supported value is 8192, otherwise the maximum value is 512. The 999 minimum value which makes sense is 2. 1000 1001 This is purely to save memory: each supported CPU adds about 8KB 1002 to the kernel image. 1003 1004config SCHED_SMT 1005 def_bool y if SMP 1006 1007config SCHED_MC 1008 def_bool y 1009 prompt "Multi-core scheduler support" 1010 depends on SMP 1011 ---help--- 1012 Multi-core scheduler support improves the CPU scheduler's decision 1013 making when dealing with multi-core CPU chips at a cost of slightly 1014 increased overhead in some places. If unsure say N here. 1015 1016config SCHED_MC_PRIO 1017 bool "CPU core priorities scheduler support" 1018 depends on SCHED_MC && CPU_SUP_INTEL 1019 select X86_INTEL_PSTATE 1020 select CPU_FREQ 1021 default y 1022 ---help--- 1023 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1024 core ordering determined at manufacturing time, which allows 1025 certain cores to reach higher turbo frequencies (when running 1026 single threaded workloads) than others. 1027 1028 Enabling this kernel feature teaches the scheduler about 1029 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1030 scheduler's CPU selection logic accordingly, so that higher 1031 overall system performance can be achieved. 1032 1033 This feature will have no effect on CPUs without this feature. 1034 1035 If unsure say Y here. 1036 1037config UP_LATE_INIT 1038 def_bool y 1039 depends on !SMP && X86_LOCAL_APIC 1040 1041config X86_UP_APIC 1042 bool "Local APIC support on uniprocessors" if !PCI_MSI 1043 default PCI_MSI 1044 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1045 ---help--- 1046 A local APIC (Advanced Programmable Interrupt Controller) is an 1047 integrated interrupt controller in the CPU. If you have a single-CPU 1048 system which has a processor with a local APIC, you can say Y here to 1049 enable and use it. If you say Y here even though your machine doesn't 1050 have a local APIC, then the kernel will still run with no slowdown at 1051 all. The local APIC supports CPU-generated self-interrupts (timer, 1052 performance counters), and the NMI watchdog which detects hard 1053 lockups. 1054 1055config X86_UP_IOAPIC 1056 bool "IO-APIC support on uniprocessors" 1057 depends on X86_UP_APIC 1058 ---help--- 1059 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1060 SMP-capable replacement for PC-style interrupt controllers. Most 1061 SMP systems and many recent uniprocessor systems have one. 1062 1063 If you have a single-CPU system with an IO-APIC, you can say Y here 1064 to use it. If you say Y here even though your machine doesn't have 1065 an IO-APIC, then the kernel will still run with no slowdown at all. 1066 1067config X86_LOCAL_APIC 1068 def_bool y 1069 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1070 select IRQ_DOMAIN_HIERARCHY 1071 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1072 1073config X86_IO_APIC 1074 def_bool y 1075 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1076 1077config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1078 bool "Reroute for broken boot IRQs" 1079 depends on X86_IO_APIC 1080 ---help--- 1081 This option enables a workaround that fixes a source of 1082 spurious interrupts. This is recommended when threaded 1083 interrupt handling is used on systems where the generation of 1084 superfluous "boot interrupts" cannot be disabled. 1085 1086 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1087 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1088 kernel does during interrupt handling). On chipsets where this 1089 boot IRQ generation cannot be disabled, this workaround keeps 1090 the original IRQ line masked so that only the equivalent "boot 1091 IRQ" is delivered to the CPUs. The workaround also tells the 1092 kernel to set up the IRQ handler on the boot IRQ line. In this 1093 way only one interrupt is delivered to the kernel. Otherwise 1094 the spurious second interrupt may cause the kernel to bring 1095 down (vital) interrupt lines. 1096 1097 Only affects "broken" chipsets. Interrupt sharing may be 1098 increased on these systems. 1099 1100config X86_MCE 1101 bool "Machine Check / overheating reporting" 1102 select GENERIC_ALLOCATOR 1103 default y 1104 ---help--- 1105 Machine Check support allows the processor to notify the 1106 kernel if it detects a problem (e.g. overheating, data corruption). 1107 The action the kernel takes depends on the severity of the problem, 1108 ranging from warning messages to halting the machine. 1109 1110config X86_MCELOG_LEGACY 1111 bool "Support for deprecated /dev/mcelog character device" 1112 depends on X86_MCE 1113 ---help--- 1114 Enable support for /dev/mcelog which is needed by the old mcelog 1115 userspace logging daemon. Consider switching to the new generation 1116 rasdaemon solution. 1117 1118config X86_MCE_INTEL 1119 def_bool y 1120 prompt "Intel MCE features" 1121 depends on X86_MCE && X86_LOCAL_APIC 1122 ---help--- 1123 Additional support for intel specific MCE features such as 1124 the thermal monitor. 1125 1126config X86_MCE_AMD 1127 def_bool y 1128 prompt "AMD MCE features" 1129 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1130 ---help--- 1131 Additional support for AMD specific MCE features such as 1132 the DRAM Error Threshold. 1133 1134config X86_ANCIENT_MCE 1135 bool "Support for old Pentium 5 / WinChip machine checks" 1136 depends on X86_32 && X86_MCE 1137 ---help--- 1138 Include support for machine check handling on old Pentium 5 or WinChip 1139 systems. These typically need to be enabled explicitly on the command 1140 line. 1141 1142config X86_MCE_THRESHOLD 1143 depends on X86_MCE_AMD || X86_MCE_INTEL 1144 def_bool y 1145 1146config X86_MCE_INJECT 1147 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1148 tristate "Machine check injector support" 1149 ---help--- 1150 Provide support for injecting machine checks for testing purposes. 1151 If you don't know what a machine check is and you don't do kernel 1152 QA it is safe to say n. 1153 1154config X86_THERMAL_VECTOR 1155 def_bool y 1156 depends on X86_MCE_INTEL 1157 1158source "arch/x86/events/Kconfig" 1159 1160config X86_LEGACY_VM86 1161 bool "Legacy VM86 support" 1162 depends on X86_32 1163 ---help--- 1164 This option allows user programs to put the CPU into V8086 1165 mode, which is an 80286-era approximation of 16-bit real mode. 1166 1167 Some very old versions of X and/or vbetool require this option 1168 for user mode setting. Similarly, DOSEMU will use it if 1169 available to accelerate real mode DOS programs. However, any 1170 recent version of DOSEMU, X, or vbetool should be fully 1171 functional even without kernel VM86 support, as they will all 1172 fall back to software emulation. Nevertheless, if you are using 1173 a 16-bit DOS program where 16-bit performance matters, vm86 1174 mode might be faster than emulation and you might want to 1175 enable this option. 1176 1177 Note that any app that works on a 64-bit kernel is unlikely to 1178 need this option, as 64-bit kernels don't, and can't, support 1179 V8086 mode. This option is also unrelated to 16-bit protected 1180 mode and is not needed to run most 16-bit programs under Wine. 1181 1182 Enabling this option increases the complexity of the kernel 1183 and slows down exception handling a tiny bit. 1184 1185 If unsure, say N here. 1186 1187config VM86 1188 bool 1189 default X86_LEGACY_VM86 1190 1191config X86_16BIT 1192 bool "Enable support for 16-bit segments" if EXPERT 1193 default y 1194 depends on MODIFY_LDT_SYSCALL 1195 ---help--- 1196 This option is required by programs like Wine to run 16-bit 1197 protected mode legacy code on x86 processors. Disabling 1198 this option saves about 300 bytes on i386, or around 6K text 1199 plus 16K runtime memory on x86-64, 1200 1201config X86_ESPFIX32 1202 def_bool y 1203 depends on X86_16BIT && X86_32 1204 1205config X86_ESPFIX64 1206 def_bool y 1207 depends on X86_16BIT && X86_64 1208 1209config X86_VSYSCALL_EMULATION 1210 bool "Enable vsyscall emulation" if EXPERT 1211 default y 1212 depends on X86_64 1213 ---help--- 1214 This enables emulation of the legacy vsyscall page. Disabling 1215 it is roughly equivalent to booting with vsyscall=none, except 1216 that it will also disable the helpful warning if a program 1217 tries to use a vsyscall. With this option set to N, offending 1218 programs will just segfault, citing addresses of the form 1219 0xffffffffff600?00. 1220 1221 This option is required by many programs built before 2013, and 1222 care should be used even with newer programs if set to N. 1223 1224 Disabling this option saves about 7K of kernel size and 1225 possibly 4K of additional runtime pagetable memory. 1226 1227config X86_IOPL_IOPERM 1228 bool "IOPERM and IOPL Emulation" 1229 default y 1230 ---help--- 1231 This enables the ioperm() and iopl() syscalls which are necessary 1232 for legacy applications. 1233 1234 Legacy IOPL support is an overbroad mechanism which allows user 1235 space aside of accessing all 65536 I/O ports also to disable 1236 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1237 capabilities and permission from potentially active security 1238 modules. 1239 1240 The emulation restricts the functionality of the syscall to 1241 only allowing the full range I/O port access, but prevents the 1242 ability to disable interrupts from user space which would be 1243 granted if the hardware IOPL mechanism would be used. 1244 1245config TOSHIBA 1246 tristate "Toshiba Laptop support" 1247 depends on X86_32 1248 ---help--- 1249 This adds a driver to safely access the System Management Mode of 1250 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1251 not work on models with a Phoenix BIOS. The System Management Mode 1252 is used to set the BIOS and power saving options on Toshiba portables. 1253 1254 For information on utilities to make use of this driver see the 1255 Toshiba Linux utilities web site at: 1256 <http://www.buzzard.org.uk/toshiba/>. 1257 1258 Say Y if you intend to run this kernel on a Toshiba portable. 1259 Say N otherwise. 1260 1261config I8K 1262 tristate "Dell i8k legacy laptop support" 1263 select HWMON 1264 select SENSORS_DELL_SMM 1265 ---help--- 1266 This option enables legacy /proc/i8k userspace interface in hwmon 1267 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1268 temperature and allows controlling fan speeds of Dell laptops via 1269 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1270 it reports also power and hotkey status. For fan speed control is 1271 needed userspace package i8kutils. 1272 1273 Say Y if you intend to run this kernel on old Dell laptops or want to 1274 use userspace package i8kutils. 1275 Say N otherwise. 1276 1277config X86_REBOOTFIXUPS 1278 bool "Enable X86 board specific fixups for reboot" 1279 depends on X86_32 1280 ---help--- 1281 This enables chipset and/or board specific fixups to be done 1282 in order to get reboot to work correctly. This is only needed on 1283 some combinations of hardware and BIOS. The symptom, for which 1284 this config is intended, is when reboot ends with a stalled/hung 1285 system. 1286 1287 Currently, the only fixup is for the Geode machines using 1288 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1289 1290 Say Y if you want to enable the fixup. Currently, it's safe to 1291 enable this option even if you don't need it. 1292 Say N otherwise. 1293 1294config MICROCODE 1295 bool "CPU microcode loading support" 1296 default y 1297 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1298 select FW_LOADER 1299 ---help--- 1300 If you say Y here, you will be able to update the microcode on 1301 Intel and AMD processors. The Intel support is for the IA32 family, 1302 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1303 AMD support is for families 0x10 and later. You will obviously need 1304 the actual microcode binary data itself which is not shipped with 1305 the Linux kernel. 1306 1307 The preferred method to load microcode from a detached initrd is described 1308 in Documentation/x86/microcode.rst. For that you need to enable 1309 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1310 initrd for microcode blobs. 1311 1312 In addition, you can build the microcode into the kernel. For that you 1313 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1314 config option. 1315 1316config MICROCODE_INTEL 1317 bool "Intel microcode loading support" 1318 depends on MICROCODE 1319 default MICROCODE 1320 select FW_LOADER 1321 ---help--- 1322 This options enables microcode patch loading support for Intel 1323 processors. 1324 1325 For the current Intel microcode data package go to 1326 <https://downloadcenter.intel.com> and search for 1327 'Linux Processor Microcode Data File'. 1328 1329config MICROCODE_AMD 1330 bool "AMD microcode loading support" 1331 depends on MICROCODE 1332 select FW_LOADER 1333 ---help--- 1334 If you select this option, microcode patch loading support for AMD 1335 processors will be enabled. 1336 1337config MICROCODE_OLD_INTERFACE 1338 bool "Ancient loading interface (DEPRECATED)" 1339 default n 1340 depends on MICROCODE 1341 ---help--- 1342 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1343 which was used by userspace tools like iucode_tool and microcode.ctl. 1344 It is inadequate because it runs too late to be able to properly 1345 load microcode on a machine and it needs special tools. Instead, you 1346 should've switched to the early loading method with the initrd or 1347 builtin microcode by now: Documentation/x86/microcode.rst 1348 1349config X86_MSR 1350 tristate "/dev/cpu/*/msr - Model-specific register support" 1351 ---help--- 1352 This device gives privileged processes access to the x86 1353 Model-Specific Registers (MSRs). It is a character device with 1354 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1355 MSR accesses are directed to a specific CPU on multi-processor 1356 systems. 1357 1358config X86_CPUID 1359 tristate "/dev/cpu/*/cpuid - CPU information support" 1360 ---help--- 1361 This device gives processes access to the x86 CPUID instruction to 1362 be executed on a specific processor. It is a character device 1363 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1364 /dev/cpu/31/cpuid. 1365 1366choice 1367 prompt "High Memory Support" 1368 default HIGHMEM4G 1369 depends on X86_32 1370 1371config NOHIGHMEM 1372 bool "off" 1373 ---help--- 1374 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1375 However, the address space of 32-bit x86 processors is only 4 1376 Gigabytes large. That means that, if you have a large amount of 1377 physical memory, not all of it can be "permanently mapped" by the 1378 kernel. The physical memory that's not permanently mapped is called 1379 "high memory". 1380 1381 If you are compiling a kernel which will never run on a machine with 1382 more than 1 Gigabyte total physical RAM, answer "off" here (default 1383 choice and suitable for most users). This will result in a "3GB/1GB" 1384 split: 3GB are mapped so that each process sees a 3GB virtual memory 1385 space and the remaining part of the 4GB virtual memory space is used 1386 by the kernel to permanently map as much physical memory as 1387 possible. 1388 1389 If the machine has between 1 and 4 Gigabytes physical RAM, then 1390 answer "4GB" here. 1391 1392 If more than 4 Gigabytes is used then answer "64GB" here. This 1393 selection turns Intel PAE (Physical Address Extension) mode on. 1394 PAE implements 3-level paging on IA32 processors. PAE is fully 1395 supported by Linux, PAE mode is implemented on all recent Intel 1396 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1397 then the kernel will not boot on CPUs that don't support PAE! 1398 1399 The actual amount of total physical memory will either be 1400 auto detected or can be forced by using a kernel command line option 1401 such as "mem=256M". (Try "man bootparam" or see the documentation of 1402 your boot loader (lilo or loadlin) about how to pass options to the 1403 kernel at boot time.) 1404 1405 If unsure, say "off". 1406 1407config HIGHMEM4G 1408 bool "4GB" 1409 ---help--- 1410 Select this if you have a 32-bit processor and between 1 and 4 1411 gigabytes of physical RAM. 1412 1413config HIGHMEM64G 1414 bool "64GB" 1415 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1416 select X86_PAE 1417 ---help--- 1418 Select this if you have a 32-bit processor and more than 4 1419 gigabytes of physical RAM. 1420 1421endchoice 1422 1423choice 1424 prompt "Memory split" if EXPERT 1425 default VMSPLIT_3G 1426 depends on X86_32 1427 ---help--- 1428 Select the desired split between kernel and user memory. 1429 1430 If the address range available to the kernel is less than the 1431 physical memory installed, the remaining memory will be available 1432 as "high memory". Accessing high memory is a little more costly 1433 than low memory, as it needs to be mapped into the kernel first. 1434 Note that increasing the kernel address space limits the range 1435 available to user programs, making the address space there 1436 tighter. Selecting anything other than the default 3G/1G split 1437 will also likely make your kernel incompatible with binary-only 1438 kernel modules. 1439 1440 If you are not absolutely sure what you are doing, leave this 1441 option alone! 1442 1443 config VMSPLIT_3G 1444 bool "3G/1G user/kernel split" 1445 config VMSPLIT_3G_OPT 1446 depends on !X86_PAE 1447 bool "3G/1G user/kernel split (for full 1G low memory)" 1448 config VMSPLIT_2G 1449 bool "2G/2G user/kernel split" 1450 config VMSPLIT_2G_OPT 1451 depends on !X86_PAE 1452 bool "2G/2G user/kernel split (for full 2G low memory)" 1453 config VMSPLIT_1G 1454 bool "1G/3G user/kernel split" 1455endchoice 1456 1457config PAGE_OFFSET 1458 hex 1459 default 0xB0000000 if VMSPLIT_3G_OPT 1460 default 0x80000000 if VMSPLIT_2G 1461 default 0x78000000 if VMSPLIT_2G_OPT 1462 default 0x40000000 if VMSPLIT_1G 1463 default 0xC0000000 1464 depends on X86_32 1465 1466config HIGHMEM 1467 def_bool y 1468 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1469 1470config X86_PAE 1471 bool "PAE (Physical Address Extension) Support" 1472 depends on X86_32 && !HIGHMEM4G 1473 select PHYS_ADDR_T_64BIT 1474 select SWIOTLB 1475 ---help--- 1476 PAE is required for NX support, and furthermore enables 1477 larger swapspace support for non-overcommit purposes. It 1478 has the cost of more pagetable lookup overhead, and also 1479 consumes more pagetable space per process. 1480 1481config X86_5LEVEL 1482 bool "Enable 5-level page tables support" 1483 default y 1484 select DYNAMIC_MEMORY_LAYOUT 1485 select SPARSEMEM_VMEMMAP 1486 depends on X86_64 1487 ---help--- 1488 5-level paging enables access to larger address space: 1489 upto 128 PiB of virtual address space and 4 PiB of 1490 physical address space. 1491 1492 It will be supported by future Intel CPUs. 1493 1494 A kernel with the option enabled can be booted on machines that 1495 support 4- or 5-level paging. 1496 1497 See Documentation/x86/x86_64/5level-paging.rst for more 1498 information. 1499 1500 Say N if unsure. 1501 1502config X86_DIRECT_GBPAGES 1503 def_bool y 1504 depends on X86_64 1505 ---help--- 1506 Certain kernel features effectively disable kernel 1507 linear 1 GB mappings (even if the CPU otherwise 1508 supports them), so don't confuse the user by printing 1509 that we have them enabled. 1510 1511config X86_CPA_STATISTICS 1512 bool "Enable statistic for Change Page Attribute" 1513 depends on DEBUG_FS 1514 ---help--- 1515 Expose statistics about the Change Page Attribute mechanims, which 1516 helps to determine the effectiveness of preserving large and huge 1517 page mappings when mapping protections are changed. 1518 1519config AMD_MEM_ENCRYPT 1520 bool "AMD Secure Memory Encryption (SME) support" 1521 depends on X86_64 && CPU_SUP_AMD 1522 select DYNAMIC_PHYSICAL_MASK 1523 select ARCH_USE_MEMREMAP_PROT 1524 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1525 ---help--- 1526 Say yes to enable support for the encryption of system memory. 1527 This requires an AMD processor that supports Secure Memory 1528 Encryption (SME). 1529 1530config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1531 bool "Activate AMD Secure Memory Encryption (SME) by default" 1532 default y 1533 depends on AMD_MEM_ENCRYPT 1534 ---help--- 1535 Say yes to have system memory encrypted by default if running on 1536 an AMD processor that supports Secure Memory Encryption (SME). 1537 1538 If set to Y, then the encryption of system memory can be 1539 deactivated with the mem_encrypt=off command line option. 1540 1541 If set to N, then the encryption of system memory can be 1542 activated with the mem_encrypt=on command line option. 1543 1544# Common NUMA Features 1545config NUMA 1546 bool "Numa Memory Allocation and Scheduler Support" 1547 depends on SMP 1548 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1549 default y if X86_BIGSMP 1550 ---help--- 1551 Enable NUMA (Non Uniform Memory Access) support. 1552 1553 The kernel will try to allocate memory used by a CPU on the 1554 local memory controller of the CPU and add some more 1555 NUMA awareness to the kernel. 1556 1557 For 64-bit this is recommended if the system is Intel Core i7 1558 (or later), AMD Opteron, or EM64T NUMA. 1559 1560 For 32-bit this is only needed if you boot a 32-bit 1561 kernel on a 64-bit NUMA platform. 1562 1563 Otherwise, you should say N. 1564 1565config AMD_NUMA 1566 def_bool y 1567 prompt "Old style AMD Opteron NUMA detection" 1568 depends on X86_64 && NUMA && PCI 1569 ---help--- 1570 Enable AMD NUMA node topology detection. You should say Y here if 1571 you have a multi processor AMD system. This uses an old method to 1572 read the NUMA configuration directly from the builtin Northbridge 1573 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1574 which also takes priority if both are compiled in. 1575 1576config X86_64_ACPI_NUMA 1577 def_bool y 1578 prompt "ACPI NUMA detection" 1579 depends on X86_64 && NUMA && ACPI && PCI 1580 select ACPI_NUMA 1581 ---help--- 1582 Enable ACPI SRAT based node topology detection. 1583 1584# Some NUMA nodes have memory ranges that span 1585# other nodes. Even though a pfn is valid and 1586# between a node's start and end pfns, it may not 1587# reside on that node. See memmap_init_zone() 1588# for details. 1589config NODES_SPAN_OTHER_NODES 1590 def_bool y 1591 depends on X86_64_ACPI_NUMA 1592 1593config NUMA_EMU 1594 bool "NUMA emulation" 1595 depends on NUMA 1596 ---help--- 1597 Enable NUMA emulation. A flat machine will be split 1598 into virtual nodes when booted with "numa=fake=N", where N is the 1599 number of nodes. This is only useful for debugging. 1600 1601config NODES_SHIFT 1602 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1603 range 1 10 1604 default "10" if MAXSMP 1605 default "6" if X86_64 1606 default "3" 1607 depends on NEED_MULTIPLE_NODES 1608 ---help--- 1609 Specify the maximum number of NUMA Nodes available on the target 1610 system. Increases memory reserved to accommodate various tables. 1611 1612config ARCH_HAVE_MEMORY_PRESENT 1613 def_bool y 1614 depends on X86_32 && DISCONTIGMEM 1615 1616config ARCH_FLATMEM_ENABLE 1617 def_bool y 1618 depends on X86_32 && !NUMA 1619 1620config ARCH_DISCONTIGMEM_ENABLE 1621 def_bool n 1622 depends on NUMA && X86_32 1623 depends on BROKEN 1624 1625config ARCH_SPARSEMEM_ENABLE 1626 def_bool y 1627 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1628 select SPARSEMEM_STATIC if X86_32 1629 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1630 1631config ARCH_SPARSEMEM_DEFAULT 1632 def_bool X86_64 || (NUMA && X86_32) 1633 1634config ARCH_SELECT_MEMORY_MODEL 1635 def_bool y 1636 depends on ARCH_SPARSEMEM_ENABLE 1637 1638config ARCH_MEMORY_PROBE 1639 bool "Enable sysfs memory/probe interface" 1640 depends on X86_64 && MEMORY_HOTPLUG 1641 help 1642 This option enables a sysfs memory/probe interface for testing. 1643 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1644 If you are unsure how to answer this question, answer N. 1645 1646config ARCH_PROC_KCORE_TEXT 1647 def_bool y 1648 depends on X86_64 && PROC_KCORE 1649 1650config ILLEGAL_POINTER_VALUE 1651 hex 1652 default 0 if X86_32 1653 default 0xdead000000000000 if X86_64 1654 1655config X86_PMEM_LEGACY_DEVICE 1656 bool 1657 1658config X86_PMEM_LEGACY 1659 tristate "Support non-standard NVDIMMs and ADR protected memory" 1660 depends on PHYS_ADDR_T_64BIT 1661 depends on BLK_DEV 1662 select X86_PMEM_LEGACY_DEVICE 1663 select LIBNVDIMM 1664 help 1665 Treat memory marked using the non-standard e820 type of 12 as used 1666 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1667 The kernel will offer these regions to the 'pmem' driver so 1668 they can be used for persistent storage. 1669 1670 Say Y if unsure. 1671 1672config HIGHPTE 1673 bool "Allocate 3rd-level pagetables from highmem" 1674 depends on HIGHMEM 1675 ---help--- 1676 The VM uses one page table entry for each page of physical memory. 1677 For systems with a lot of RAM, this can be wasteful of precious 1678 low memory. Setting this option will put user-space page table 1679 entries in high memory. 1680 1681config X86_CHECK_BIOS_CORRUPTION 1682 bool "Check for low memory corruption" 1683 ---help--- 1684 Periodically check for memory corruption in low memory, which 1685 is suspected to be caused by BIOS. Even when enabled in the 1686 configuration, it is disabled at runtime. Enable it by 1687 setting "memory_corruption_check=1" on the kernel command 1688 line. By default it scans the low 64k of memory every 60 1689 seconds; see the memory_corruption_check_size and 1690 memory_corruption_check_period parameters in 1691 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1692 1693 When enabled with the default parameters, this option has 1694 almost no overhead, as it reserves a relatively small amount 1695 of memory and scans it infrequently. It both detects corruption 1696 and prevents it from affecting the running system. 1697 1698 It is, however, intended as a diagnostic tool; if repeatable 1699 BIOS-originated corruption always affects the same memory, 1700 you can use memmap= to prevent the kernel from using that 1701 memory. 1702 1703config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1704 bool "Set the default setting of memory_corruption_check" 1705 depends on X86_CHECK_BIOS_CORRUPTION 1706 default y 1707 ---help--- 1708 Set whether the default state of memory_corruption_check is 1709 on or off. 1710 1711config X86_RESERVE_LOW 1712 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1713 default 64 1714 range 4 640 1715 ---help--- 1716 Specify the amount of low memory to reserve for the BIOS. 1717 1718 The first page contains BIOS data structures that the kernel 1719 must not use, so that page must always be reserved. 1720 1721 By default we reserve the first 64K of physical RAM, as a 1722 number of BIOSes are known to corrupt that memory range 1723 during events such as suspend/resume or monitor cable 1724 insertion, so it must not be used by the kernel. 1725 1726 You can set this to 4 if you are absolutely sure that you 1727 trust the BIOS to get all its memory reservations and usages 1728 right. If you know your BIOS have problems beyond the 1729 default 64K area, you can set this to 640 to avoid using the 1730 entire low memory range. 1731 1732 If you have doubts about the BIOS (e.g. suspend/resume does 1733 not work or there's kernel crashes after certain hardware 1734 hotplug events) then you might want to enable 1735 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1736 typical corruption patterns. 1737 1738 Leave this to the default value of 64 if you are unsure. 1739 1740config MATH_EMULATION 1741 bool 1742 depends on MODIFY_LDT_SYSCALL 1743 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1744 ---help--- 1745 Linux can emulate a math coprocessor (used for floating point 1746 operations) if you don't have one. 486DX and Pentium processors have 1747 a math coprocessor built in, 486SX and 386 do not, unless you added 1748 a 487DX or 387, respectively. (The messages during boot time can 1749 give you some hints here ["man dmesg"].) Everyone needs either a 1750 coprocessor or this emulation. 1751 1752 If you don't have a math coprocessor, you need to say Y here; if you 1753 say Y here even though you have a coprocessor, the coprocessor will 1754 be used nevertheless. (This behavior can be changed with the kernel 1755 command line option "no387", which comes handy if your coprocessor 1756 is broken. Try "man bootparam" or see the documentation of your boot 1757 loader (lilo or loadlin) about how to pass options to the kernel at 1758 boot time.) This means that it is a good idea to say Y here if you 1759 intend to use this kernel on different machines. 1760 1761 More information about the internals of the Linux math coprocessor 1762 emulation can be found in <file:arch/x86/math-emu/README>. 1763 1764 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1765 kernel, it won't hurt. 1766 1767config MTRR 1768 def_bool y 1769 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1770 ---help--- 1771 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1772 the Memory Type Range Registers (MTRRs) may be used to control 1773 processor access to memory ranges. This is most useful if you have 1774 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1775 allows bus write transfers to be combined into a larger transfer 1776 before bursting over the PCI/AGP bus. This can increase performance 1777 of image write operations 2.5 times or more. Saying Y here creates a 1778 /proc/mtrr file which may be used to manipulate your processor's 1779 MTRRs. Typically the X server should use this. 1780 1781 This code has a reasonably generic interface so that similar 1782 control registers on other processors can be easily supported 1783 as well: 1784 1785 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1786 Registers (ARRs) which provide a similar functionality to MTRRs. For 1787 these, the ARRs are used to emulate the MTRRs. 1788 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1789 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1790 write-combining. All of these processors are supported by this code 1791 and it makes sense to say Y here if you have one of them. 1792 1793 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1794 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1795 can lead to all sorts of problems, so it's good to say Y here. 1796 1797 You can safely say Y even if your machine doesn't have MTRRs, you'll 1798 just add about 9 KB to your kernel. 1799 1800 See <file:Documentation/x86/mtrr.rst> for more information. 1801 1802config MTRR_SANITIZER 1803 def_bool y 1804 prompt "MTRR cleanup support" 1805 depends on MTRR 1806 ---help--- 1807 Convert MTRR layout from continuous to discrete, so X drivers can 1808 add writeback entries. 1809 1810 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1811 The largest mtrr entry size for a continuous block can be set with 1812 mtrr_chunk_size. 1813 1814 If unsure, say Y. 1815 1816config MTRR_SANITIZER_ENABLE_DEFAULT 1817 int "MTRR cleanup enable value (0-1)" 1818 range 0 1 1819 default "0" 1820 depends on MTRR_SANITIZER 1821 ---help--- 1822 Enable mtrr cleanup default value 1823 1824config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1825 int "MTRR cleanup spare reg num (0-7)" 1826 range 0 7 1827 default "1" 1828 depends on MTRR_SANITIZER 1829 ---help--- 1830 mtrr cleanup spare entries default, it can be changed via 1831 mtrr_spare_reg_nr=N on the kernel command line. 1832 1833config X86_PAT 1834 def_bool y 1835 prompt "x86 PAT support" if EXPERT 1836 depends on MTRR 1837 ---help--- 1838 Use PAT attributes to setup page level cache control. 1839 1840 PATs are the modern equivalents of MTRRs and are much more 1841 flexible than MTRRs. 1842 1843 Say N here if you see bootup problems (boot crash, boot hang, 1844 spontaneous reboots) or a non-working video driver. 1845 1846 If unsure, say Y. 1847 1848config ARCH_USES_PG_UNCACHED 1849 def_bool y 1850 depends on X86_PAT 1851 1852config ARCH_RANDOM 1853 def_bool y 1854 prompt "x86 architectural random number generator" if EXPERT 1855 ---help--- 1856 Enable the x86 architectural RDRAND instruction 1857 (Intel Bull Mountain technology) to generate random numbers. 1858 If supported, this is a high bandwidth, cryptographically 1859 secure hardware random number generator. 1860 1861config X86_SMAP 1862 def_bool y 1863 prompt "Supervisor Mode Access Prevention" if EXPERT 1864 ---help--- 1865 Supervisor Mode Access Prevention (SMAP) is a security 1866 feature in newer Intel processors. There is a small 1867 performance cost if this enabled and turned on; there is 1868 also a small increase in the kernel size if this is enabled. 1869 1870 If unsure, say Y. 1871 1872config X86_UMIP 1873 def_bool y 1874 depends on CPU_SUP_INTEL || CPU_SUP_AMD 1875 prompt "User Mode Instruction Prevention" if EXPERT 1876 ---help--- 1877 User Mode Instruction Prevention (UMIP) is a security feature in 1878 some x86 processors. If enabled, a general protection fault is 1879 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1880 executed in user mode. These instructions unnecessarily expose 1881 information about the hardware state. 1882 1883 The vast majority of applications do not use these instructions. 1884 For the very few that do, software emulation is provided in 1885 specific cases in protected and virtual-8086 modes. Emulated 1886 results are dummy. 1887 1888config X86_INTEL_MPX 1889 prompt "Intel MPX (Memory Protection Extensions)" 1890 def_bool n 1891 # Note: only available in 64-bit mode due to VMA flags shortage 1892 depends on CPU_SUP_INTEL && X86_64 1893 select ARCH_USES_HIGH_VMA_FLAGS 1894 ---help--- 1895 MPX provides hardware features that can be used in 1896 conjunction with compiler-instrumented code to check 1897 memory references. It is designed to detect buffer 1898 overflow or underflow bugs. 1899 1900 This option enables running applications which are 1901 instrumented or otherwise use MPX. It does not use MPX 1902 itself inside the kernel or to protect the kernel 1903 against bad memory references. 1904 1905 Enabling this option will make the kernel larger: 1906 ~8k of kernel text and 36 bytes of data on a 64-bit 1907 defconfig. It adds a long to the 'mm_struct' which 1908 will increase the kernel memory overhead of each 1909 process and adds some branches to paths used during 1910 exec() and munmap(). 1911 1912 For details, see Documentation/x86/intel_mpx.rst 1913 1914 If unsure, say N. 1915 1916config X86_INTEL_MEMORY_PROTECTION_KEYS 1917 prompt "Intel Memory Protection Keys" 1918 def_bool y 1919 # Note: only available in 64-bit mode 1920 depends on CPU_SUP_INTEL && X86_64 1921 select ARCH_USES_HIGH_VMA_FLAGS 1922 select ARCH_HAS_PKEYS 1923 ---help--- 1924 Memory Protection Keys provides a mechanism for enforcing 1925 page-based protections, but without requiring modification of the 1926 page tables when an application changes protection domains. 1927 1928 For details, see Documentation/core-api/protection-keys.rst 1929 1930 If unsure, say y. 1931 1932choice 1933 prompt "TSX enable mode" 1934 depends on CPU_SUP_INTEL 1935 default X86_INTEL_TSX_MODE_OFF 1936 help 1937 Intel's TSX (Transactional Synchronization Extensions) feature 1938 allows to optimize locking protocols through lock elision which 1939 can lead to a noticeable performance boost. 1940 1941 On the other hand it has been shown that TSX can be exploited 1942 to form side channel attacks (e.g. TAA) and chances are there 1943 will be more of those attacks discovered in the future. 1944 1945 Therefore TSX is not enabled by default (aka tsx=off). An admin 1946 might override this decision by tsx=on the command line parameter. 1947 Even with TSX enabled, the kernel will attempt to enable the best 1948 possible TAA mitigation setting depending on the microcode available 1949 for the particular machine. 1950 1951 This option allows to set the default tsx mode between tsx=on, =off 1952 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1953 details. 1954 1955 Say off if not sure, auto if TSX is in use but it should be used on safe 1956 platforms or on if TSX is in use and the security aspect of tsx is not 1957 relevant. 1958 1959config X86_INTEL_TSX_MODE_OFF 1960 bool "off" 1961 help 1962 TSX is disabled if possible - equals to tsx=off command line parameter. 1963 1964config X86_INTEL_TSX_MODE_ON 1965 bool "on" 1966 help 1967 TSX is always enabled on TSX capable HW - equals the tsx=on command 1968 line parameter. 1969 1970config X86_INTEL_TSX_MODE_AUTO 1971 bool "auto" 1972 help 1973 TSX is enabled on TSX capable HW that is believed to be safe against 1974 side channel attacks- equals the tsx=auto command line parameter. 1975endchoice 1976 1977config EFI 1978 bool "EFI runtime service support" 1979 depends on ACPI 1980 select UCS2_STRING 1981 select EFI_RUNTIME_WRAPPERS 1982 ---help--- 1983 This enables the kernel to use EFI runtime services that are 1984 available (such as the EFI variable services). 1985 1986 This option is only useful on systems that have EFI firmware. 1987 In addition, you should use the latest ELILO loader available 1988 at <http://elilo.sourceforge.net> in order to take advantage 1989 of EFI runtime services. However, even with this option, the 1990 resultant kernel should continue to boot on existing non-EFI 1991 platforms. 1992 1993config EFI_STUB 1994 bool "EFI stub support" 1995 depends on EFI && !X86_USE_3DNOW 1996 select RELOCATABLE 1997 ---help--- 1998 This kernel feature allows a bzImage to be loaded directly 1999 by EFI firmware without the use of a bootloader. 2000 2001 See Documentation/admin-guide/efi-stub.rst for more information. 2002 2003config EFI_MIXED 2004 bool "EFI mixed-mode support" 2005 depends on EFI_STUB && X86_64 2006 ---help--- 2007 Enabling this feature allows a 64-bit kernel to be booted 2008 on a 32-bit firmware, provided that your CPU supports 64-bit 2009 mode. 2010 2011 Note that it is not possible to boot a mixed-mode enabled 2012 kernel via the EFI boot stub - a bootloader that supports 2013 the EFI handover protocol must be used. 2014 2015 If unsure, say N. 2016 2017config SECCOMP 2018 def_bool y 2019 prompt "Enable seccomp to safely compute untrusted bytecode" 2020 ---help--- 2021 This kernel feature is useful for number crunching applications 2022 that may need to compute untrusted bytecode during their 2023 execution. By using pipes or other transports made available to 2024 the process as file descriptors supporting the read/write 2025 syscalls, it's possible to isolate those applications in 2026 their own address space using seccomp. Once seccomp is 2027 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 2028 and the task is only allowed to execute a few safe syscalls 2029 defined by each seccomp mode. 2030 2031 If unsure, say Y. Only embedded should say N here. 2032 2033source "kernel/Kconfig.hz" 2034 2035config KEXEC 2036 bool "kexec system call" 2037 select KEXEC_CORE 2038 ---help--- 2039 kexec is a system call that implements the ability to shutdown your 2040 current kernel, and to start another kernel. It is like a reboot 2041 but it is independent of the system firmware. And like a reboot 2042 you can start any kernel with it, not just Linux. 2043 2044 The name comes from the similarity to the exec system call. 2045 2046 It is an ongoing process to be certain the hardware in a machine 2047 is properly shutdown, so do not be surprised if this code does not 2048 initially work for you. As of this writing the exact hardware 2049 interface is strongly in flux, so no good recommendation can be 2050 made. 2051 2052config KEXEC_FILE 2053 bool "kexec file based system call" 2054 select KEXEC_CORE 2055 select BUILD_BIN2C 2056 depends on X86_64 2057 depends on CRYPTO=y 2058 depends on CRYPTO_SHA256=y 2059 ---help--- 2060 This is new version of kexec system call. This system call is 2061 file based and takes file descriptors as system call argument 2062 for kernel and initramfs as opposed to list of segments as 2063 accepted by previous system call. 2064 2065config ARCH_HAS_KEXEC_PURGATORY 2066 def_bool KEXEC_FILE 2067 2068config KEXEC_SIG 2069 bool "Verify kernel signature during kexec_file_load() syscall" 2070 depends on KEXEC_FILE 2071 ---help--- 2072 2073 This option makes the kexec_file_load() syscall check for a valid 2074 signature of the kernel image. The image can still be loaded without 2075 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2076 there's a signature that we can check, then it must be valid. 2077 2078 In addition to this option, you need to enable signature 2079 verification for the corresponding kernel image type being 2080 loaded in order for this to work. 2081 2082config KEXEC_SIG_FORCE 2083 bool "Require a valid signature in kexec_file_load() syscall" 2084 depends on KEXEC_SIG 2085 ---help--- 2086 This option makes kernel signature verification mandatory for 2087 the kexec_file_load() syscall. 2088 2089config KEXEC_BZIMAGE_VERIFY_SIG 2090 bool "Enable bzImage signature verification support" 2091 depends on KEXEC_SIG 2092 depends on SIGNED_PE_FILE_VERIFICATION 2093 select SYSTEM_TRUSTED_KEYRING 2094 ---help--- 2095 Enable bzImage signature verification support. 2096 2097config CRASH_DUMP 2098 bool "kernel crash dumps" 2099 depends on X86_64 || (X86_32 && HIGHMEM) 2100 ---help--- 2101 Generate crash dump after being started by kexec. 2102 This should be normally only set in special crash dump kernels 2103 which are loaded in the main kernel with kexec-tools into 2104 a specially reserved region and then later executed after 2105 a crash by kdump/kexec. The crash dump kernel must be compiled 2106 to a memory address not used by the main kernel or BIOS using 2107 PHYSICAL_START, or it must be built as a relocatable image 2108 (CONFIG_RELOCATABLE=y). 2109 For more details see Documentation/admin-guide/kdump/kdump.rst 2110 2111config KEXEC_JUMP 2112 bool "kexec jump" 2113 depends on KEXEC && HIBERNATION 2114 ---help--- 2115 Jump between original kernel and kexeced kernel and invoke 2116 code in physical address mode via KEXEC 2117 2118config PHYSICAL_START 2119 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2120 default "0x1000000" 2121 ---help--- 2122 This gives the physical address where the kernel is loaded. 2123 2124 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2125 bzImage will decompress itself to above physical address and 2126 run from there. Otherwise, bzImage will run from the address where 2127 it has been loaded by the boot loader and will ignore above physical 2128 address. 2129 2130 In normal kdump cases one does not have to set/change this option 2131 as now bzImage can be compiled as a completely relocatable image 2132 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2133 address. This option is mainly useful for the folks who don't want 2134 to use a bzImage for capturing the crash dump and want to use a 2135 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2136 to be specifically compiled to run from a specific memory area 2137 (normally a reserved region) and this option comes handy. 2138 2139 So if you are using bzImage for capturing the crash dump, 2140 leave the value here unchanged to 0x1000000 and set 2141 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2142 for capturing the crash dump change this value to start of 2143 the reserved region. In other words, it can be set based on 2144 the "X" value as specified in the "crashkernel=YM@XM" 2145 command line boot parameter passed to the panic-ed 2146 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2147 for more details about crash dumps. 2148 2149 Usage of bzImage for capturing the crash dump is recommended as 2150 one does not have to build two kernels. Same kernel can be used 2151 as production kernel and capture kernel. Above option should have 2152 gone away after relocatable bzImage support is introduced. But it 2153 is present because there are users out there who continue to use 2154 vmlinux for dump capture. This option should go away down the 2155 line. 2156 2157 Don't change this unless you know what you are doing. 2158 2159config RELOCATABLE 2160 bool "Build a relocatable kernel" 2161 default y 2162 ---help--- 2163 This builds a kernel image that retains relocation information 2164 so it can be loaded someplace besides the default 1MB. 2165 The relocations tend to make the kernel binary about 10% larger, 2166 but are discarded at runtime. 2167 2168 One use is for the kexec on panic case where the recovery kernel 2169 must live at a different physical address than the primary 2170 kernel. 2171 2172 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2173 it has been loaded at and the compile time physical address 2174 (CONFIG_PHYSICAL_START) is used as the minimum location. 2175 2176config RANDOMIZE_BASE 2177 bool "Randomize the address of the kernel image (KASLR)" 2178 depends on RELOCATABLE 2179 default y 2180 ---help--- 2181 In support of Kernel Address Space Layout Randomization (KASLR), 2182 this randomizes the physical address at which the kernel image 2183 is decompressed and the virtual address where the kernel 2184 image is mapped, as a security feature that deters exploit 2185 attempts relying on knowledge of the location of kernel 2186 code internals. 2187 2188 On 64-bit, the kernel physical and virtual addresses are 2189 randomized separately. The physical address will be anywhere 2190 between 16MB and the top of physical memory (up to 64TB). The 2191 virtual address will be randomized from 16MB up to 1GB (9 bits 2192 of entropy). Note that this also reduces the memory space 2193 available to kernel modules from 1.5GB to 1GB. 2194 2195 On 32-bit, the kernel physical and virtual addresses are 2196 randomized together. They will be randomized from 16MB up to 2197 512MB (8 bits of entropy). 2198 2199 Entropy is generated using the RDRAND instruction if it is 2200 supported. If RDTSC is supported, its value is mixed into 2201 the entropy pool as well. If neither RDRAND nor RDTSC are 2202 supported, then entropy is read from the i8254 timer. The 2203 usable entropy is limited by the kernel being built using 2204 2GB addressing, and that PHYSICAL_ALIGN must be at a 2205 minimum of 2MB. As a result, only 10 bits of entropy are 2206 theoretically possible, but the implementations are further 2207 limited due to memory layouts. 2208 2209 If unsure, say Y. 2210 2211# Relocation on x86 needs some additional build support 2212config X86_NEED_RELOCS 2213 def_bool y 2214 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2215 2216config PHYSICAL_ALIGN 2217 hex "Alignment value to which kernel should be aligned" 2218 default "0x200000" 2219 range 0x2000 0x1000000 if X86_32 2220 range 0x200000 0x1000000 if X86_64 2221 ---help--- 2222 This value puts the alignment restrictions on physical address 2223 where kernel is loaded and run from. Kernel is compiled for an 2224 address which meets above alignment restriction. 2225 2226 If bootloader loads the kernel at a non-aligned address and 2227 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2228 address aligned to above value and run from there. 2229 2230 If bootloader loads the kernel at a non-aligned address and 2231 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2232 load address and decompress itself to the address it has been 2233 compiled for and run from there. The address for which kernel is 2234 compiled already meets above alignment restrictions. Hence the 2235 end result is that kernel runs from a physical address meeting 2236 above alignment restrictions. 2237 2238 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2239 this value must be a multiple of 0x200000. 2240 2241 Don't change this unless you know what you are doing. 2242 2243config DYNAMIC_MEMORY_LAYOUT 2244 bool 2245 ---help--- 2246 This option makes base addresses of vmalloc and vmemmap as well as 2247 __PAGE_OFFSET movable during boot. 2248 2249config RANDOMIZE_MEMORY 2250 bool "Randomize the kernel memory sections" 2251 depends on X86_64 2252 depends on RANDOMIZE_BASE 2253 select DYNAMIC_MEMORY_LAYOUT 2254 default RANDOMIZE_BASE 2255 ---help--- 2256 Randomizes the base virtual address of kernel memory sections 2257 (physical memory mapping, vmalloc & vmemmap). This security feature 2258 makes exploits relying on predictable memory locations less reliable. 2259 2260 The order of allocations remains unchanged. Entropy is generated in 2261 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2262 configuration have in average 30,000 different possible virtual 2263 addresses for each memory section. 2264 2265 If unsure, say Y. 2266 2267config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2268 hex "Physical memory mapping padding" if EXPERT 2269 depends on RANDOMIZE_MEMORY 2270 default "0xa" if MEMORY_HOTPLUG 2271 default "0x0" 2272 range 0x1 0x40 if MEMORY_HOTPLUG 2273 range 0x0 0x40 2274 ---help--- 2275 Define the padding in terabytes added to the existing physical 2276 memory size during kernel memory randomization. It is useful 2277 for memory hotplug support but reduces the entropy available for 2278 address randomization. 2279 2280 If unsure, leave at the default value. 2281 2282config HOTPLUG_CPU 2283 def_bool y 2284 depends on SMP 2285 2286config BOOTPARAM_HOTPLUG_CPU0 2287 bool "Set default setting of cpu0_hotpluggable" 2288 depends on HOTPLUG_CPU 2289 ---help--- 2290 Set whether default state of cpu0_hotpluggable is on or off. 2291 2292 Say Y here to enable CPU0 hotplug by default. If this switch 2293 is turned on, there is no need to give cpu0_hotplug kernel 2294 parameter and the CPU0 hotplug feature is enabled by default. 2295 2296 Please note: there are two known CPU0 dependencies if you want 2297 to enable the CPU0 hotplug feature either by this switch or by 2298 cpu0_hotplug kernel parameter. 2299 2300 First, resume from hibernate or suspend always starts from CPU0. 2301 So hibernate and suspend are prevented if CPU0 is offline. 2302 2303 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2304 offline if any interrupt can not migrate out of CPU0. There may 2305 be other CPU0 dependencies. 2306 2307 Please make sure the dependencies are under your control before 2308 you enable this feature. 2309 2310 Say N if you don't want to enable CPU0 hotplug feature by default. 2311 You still can enable the CPU0 hotplug feature at boot by kernel 2312 parameter cpu0_hotplug. 2313 2314config DEBUG_HOTPLUG_CPU0 2315 def_bool n 2316 prompt "Debug CPU0 hotplug" 2317 depends on HOTPLUG_CPU 2318 ---help--- 2319 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2320 soon as possible and boots up userspace with CPU0 offlined. User 2321 can online CPU0 back after boot time. 2322 2323 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2324 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2325 compilation or giving cpu0_hotplug kernel parameter at boot. 2326 2327 If unsure, say N. 2328 2329config COMPAT_VDSO 2330 def_bool n 2331 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2332 depends on COMPAT_32 2333 ---help--- 2334 Certain buggy versions of glibc will crash if they are 2335 presented with a 32-bit vDSO that is not mapped at the address 2336 indicated in its segment table. 2337 2338 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2339 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2340 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2341 the only released version with the bug, but OpenSUSE 9 2342 contains a buggy "glibc 2.3.2". 2343 2344 The symptom of the bug is that everything crashes on startup, saying: 2345 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2346 2347 Saying Y here changes the default value of the vdso32 boot 2348 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2349 This works around the glibc bug but hurts performance. 2350 2351 If unsure, say N: if you are compiling your own kernel, you 2352 are unlikely to be using a buggy version of glibc. 2353 2354choice 2355 prompt "vsyscall table for legacy applications" 2356 depends on X86_64 2357 default LEGACY_VSYSCALL_XONLY 2358 help 2359 Legacy user code that does not know how to find the vDSO expects 2360 to be able to issue three syscalls by calling fixed addresses in 2361 kernel space. Since this location is not randomized with ASLR, 2362 it can be used to assist security vulnerability exploitation. 2363 2364 This setting can be changed at boot time via the kernel command 2365 line parameter vsyscall=[emulate|xonly|none]. 2366 2367 On a system with recent enough glibc (2.14 or newer) and no 2368 static binaries, you can say None without a performance penalty 2369 to improve security. 2370 2371 If unsure, select "Emulate execution only". 2372 2373 config LEGACY_VSYSCALL_EMULATE 2374 bool "Full emulation" 2375 help 2376 The kernel traps and emulates calls into the fixed vsyscall 2377 address mapping. This makes the mapping non-executable, but 2378 it still contains readable known contents, which could be 2379 used in certain rare security vulnerability exploits. This 2380 configuration is recommended when using legacy userspace 2381 that still uses vsyscalls along with legacy binary 2382 instrumentation tools that require code to be readable. 2383 2384 An example of this type of legacy userspace is running 2385 Pin on an old binary that still uses vsyscalls. 2386 2387 config LEGACY_VSYSCALL_XONLY 2388 bool "Emulate execution only" 2389 help 2390 The kernel traps and emulates calls into the fixed vsyscall 2391 address mapping and does not allow reads. This 2392 configuration is recommended when userspace might use the 2393 legacy vsyscall area but support for legacy binary 2394 instrumentation of legacy code is not needed. It mitigates 2395 certain uses of the vsyscall area as an ASLR-bypassing 2396 buffer. 2397 2398 config LEGACY_VSYSCALL_NONE 2399 bool "None" 2400 help 2401 There will be no vsyscall mapping at all. This will 2402 eliminate any risk of ASLR bypass due to the vsyscall 2403 fixed address mapping. Attempts to use the vsyscalls 2404 will be reported to dmesg, so that either old or 2405 malicious userspace programs can be identified. 2406 2407endchoice 2408 2409config CMDLINE_BOOL 2410 bool "Built-in kernel command line" 2411 ---help--- 2412 Allow for specifying boot arguments to the kernel at 2413 build time. On some systems (e.g. embedded ones), it is 2414 necessary or convenient to provide some or all of the 2415 kernel boot arguments with the kernel itself (that is, 2416 to not rely on the boot loader to provide them.) 2417 2418 To compile command line arguments into the kernel, 2419 set this option to 'Y', then fill in the 2420 boot arguments in CONFIG_CMDLINE. 2421 2422 Systems with fully functional boot loaders (i.e. non-embedded) 2423 should leave this option set to 'N'. 2424 2425config CMDLINE 2426 string "Built-in kernel command string" 2427 depends on CMDLINE_BOOL 2428 default "" 2429 ---help--- 2430 Enter arguments here that should be compiled into the kernel 2431 image and used at boot time. If the boot loader provides a 2432 command line at boot time, it is appended to this string to 2433 form the full kernel command line, when the system boots. 2434 2435 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2436 change this behavior. 2437 2438 In most cases, the command line (whether built-in or provided 2439 by the boot loader) should specify the device for the root 2440 file system. 2441 2442config CMDLINE_OVERRIDE 2443 bool "Built-in command line overrides boot loader arguments" 2444 depends on CMDLINE_BOOL 2445 ---help--- 2446 Set this option to 'Y' to have the kernel ignore the boot loader 2447 command line, and use ONLY the built-in command line. 2448 2449 This is used to work around broken boot loaders. This should 2450 be set to 'N' under normal conditions. 2451 2452config MODIFY_LDT_SYSCALL 2453 bool "Enable the LDT (local descriptor table)" if EXPERT 2454 default y 2455 ---help--- 2456 Linux can allow user programs to install a per-process x86 2457 Local Descriptor Table (LDT) using the modify_ldt(2) system 2458 call. This is required to run 16-bit or segmented code such as 2459 DOSEMU or some Wine programs. It is also used by some very old 2460 threading libraries. 2461 2462 Enabling this feature adds a small amount of overhead to 2463 context switches and increases the low-level kernel attack 2464 surface. Disabling it removes the modify_ldt(2) system call. 2465 2466 Saying 'N' here may make sense for embedded or server kernels. 2467 2468source "kernel/livepatch/Kconfig" 2469 2470endmenu 2471 2472config ARCH_HAS_ADD_PAGES 2473 def_bool y 2474 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2475 2476config ARCH_ENABLE_MEMORY_HOTPLUG 2477 def_bool y 2478 depends on X86_64 || (X86_32 && HIGHMEM) 2479 2480config ARCH_ENABLE_MEMORY_HOTREMOVE 2481 def_bool y 2482 depends on MEMORY_HOTPLUG 2483 2484config USE_PERCPU_NUMA_NODE_ID 2485 def_bool y 2486 depends on NUMA 2487 2488config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2489 def_bool y 2490 depends on X86_64 || X86_PAE 2491 2492config ARCH_ENABLE_HUGEPAGE_MIGRATION 2493 def_bool y 2494 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2495 2496config ARCH_ENABLE_THP_MIGRATION 2497 def_bool y 2498 depends on X86_64 && TRANSPARENT_HUGEPAGE 2499 2500menu "Power management and ACPI options" 2501 2502config ARCH_HIBERNATION_HEADER 2503 def_bool y 2504 depends on HIBERNATION 2505 2506source "kernel/power/Kconfig" 2507 2508source "drivers/acpi/Kconfig" 2509 2510source "drivers/sfi/Kconfig" 2511 2512config X86_APM_BOOT 2513 def_bool y 2514 depends on APM 2515 2516menuconfig APM 2517 tristate "APM (Advanced Power Management) BIOS support" 2518 depends on X86_32 && PM_SLEEP 2519 ---help--- 2520 APM is a BIOS specification for saving power using several different 2521 techniques. This is mostly useful for battery powered laptops with 2522 APM compliant BIOSes. If you say Y here, the system time will be 2523 reset after a RESUME operation, the /proc/apm device will provide 2524 battery status information, and user-space programs will receive 2525 notification of APM "events" (e.g. battery status change). 2526 2527 If you select "Y" here, you can disable actual use of the APM 2528 BIOS by passing the "apm=off" option to the kernel at boot time. 2529 2530 Note that the APM support is almost completely disabled for 2531 machines with more than one CPU. 2532 2533 In order to use APM, you will need supporting software. For location 2534 and more information, read <file:Documentation/power/apm-acpi.rst> 2535 and the Battery Powered Linux mini-HOWTO, available from 2536 <http://www.tldp.org/docs.html#howto>. 2537 2538 This driver does not spin down disk drives (see the hdparm(8) 2539 manpage ("man 8 hdparm") for that), and it doesn't turn off 2540 VESA-compliant "green" monitors. 2541 2542 This driver does not support the TI 4000M TravelMate and the ACER 2543 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2544 desktop machines also don't have compliant BIOSes, and this driver 2545 may cause those machines to panic during the boot phase. 2546 2547 Generally, if you don't have a battery in your machine, there isn't 2548 much point in using this driver and you should say N. If you get 2549 random kernel OOPSes or reboots that don't seem to be related to 2550 anything, try disabling/enabling this option (or disabling/enabling 2551 APM in your BIOS). 2552 2553 Some other things you should try when experiencing seemingly random, 2554 "weird" problems: 2555 2556 1) make sure that you have enough swap space and that it is 2557 enabled. 2558 2) pass the "no-hlt" option to the kernel 2559 3) switch on floating point emulation in the kernel and pass 2560 the "no387" option to the kernel 2561 4) pass the "floppy=nodma" option to the kernel 2562 5) pass the "mem=4M" option to the kernel (thereby disabling 2563 all but the first 4 MB of RAM) 2564 6) make sure that the CPU is not over clocked. 2565 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2566 8) disable the cache from your BIOS settings 2567 9) install a fan for the video card or exchange video RAM 2568 10) install a better fan for the CPU 2569 11) exchange RAM chips 2570 12) exchange the motherboard. 2571 2572 To compile this driver as a module, choose M here: the 2573 module will be called apm. 2574 2575if APM 2576 2577config APM_IGNORE_USER_SUSPEND 2578 bool "Ignore USER SUSPEND" 2579 ---help--- 2580 This option will ignore USER SUSPEND requests. On machines with a 2581 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2582 series notebooks, it is necessary to say Y because of a BIOS bug. 2583 2584config APM_DO_ENABLE 2585 bool "Enable PM at boot time" 2586 ---help--- 2587 Enable APM features at boot time. From page 36 of the APM BIOS 2588 specification: "When disabled, the APM BIOS does not automatically 2589 power manage devices, enter the Standby State, enter the Suspend 2590 State, or take power saving steps in response to CPU Idle calls." 2591 This driver will make CPU Idle calls when Linux is idle (unless this 2592 feature is turned off -- see "Do CPU IDLE calls", below). This 2593 should always save battery power, but more complicated APM features 2594 will be dependent on your BIOS implementation. You may need to turn 2595 this option off if your computer hangs at boot time when using APM 2596 support, or if it beeps continuously instead of suspending. Turn 2597 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2598 T400CDT. This is off by default since most machines do fine without 2599 this feature. 2600 2601config APM_CPU_IDLE 2602 depends on CPU_IDLE 2603 bool "Make CPU Idle calls when idle" 2604 ---help--- 2605 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2606 On some machines, this can activate improved power savings, such as 2607 a slowed CPU clock rate, when the machine is idle. These idle calls 2608 are made after the idle loop has run for some length of time (e.g., 2609 333 mS). On some machines, this will cause a hang at boot time or 2610 whenever the CPU becomes idle. (On machines with more than one CPU, 2611 this option does nothing.) 2612 2613config APM_DISPLAY_BLANK 2614 bool "Enable console blanking using APM" 2615 ---help--- 2616 Enable console blanking using the APM. Some laptops can use this to 2617 turn off the LCD backlight when the screen blanker of the Linux 2618 virtual console blanks the screen. Note that this is only used by 2619 the virtual console screen blanker, and won't turn off the backlight 2620 when using the X Window system. This also doesn't have anything to 2621 do with your VESA-compliant power-saving monitor. Further, this 2622 option doesn't work for all laptops -- it might not turn off your 2623 backlight at all, or it might print a lot of errors to the console, 2624 especially if you are using gpm. 2625 2626config APM_ALLOW_INTS 2627 bool "Allow interrupts during APM BIOS calls" 2628 ---help--- 2629 Normally we disable external interrupts while we are making calls to 2630 the APM BIOS as a measure to lessen the effects of a badly behaving 2631 BIOS implementation. The BIOS should reenable interrupts if it 2632 needs to. Unfortunately, some BIOSes do not -- especially those in 2633 many of the newer IBM Thinkpads. If you experience hangs when you 2634 suspend, try setting this to Y. Otherwise, say N. 2635 2636endif # APM 2637 2638source "drivers/cpufreq/Kconfig" 2639 2640source "drivers/cpuidle/Kconfig" 2641 2642source "drivers/idle/Kconfig" 2643 2644endmenu 2645 2646 2647menu "Bus options (PCI etc.)" 2648 2649choice 2650 prompt "PCI access mode" 2651 depends on X86_32 && PCI 2652 default PCI_GOANY 2653 ---help--- 2654 On PCI systems, the BIOS can be used to detect the PCI devices and 2655 determine their configuration. However, some old PCI motherboards 2656 have BIOS bugs and may crash if this is done. Also, some embedded 2657 PCI-based systems don't have any BIOS at all. Linux can also try to 2658 detect the PCI hardware directly without using the BIOS. 2659 2660 With this option, you can specify how Linux should detect the 2661 PCI devices. If you choose "BIOS", the BIOS will be used, 2662 if you choose "Direct", the BIOS won't be used, and if you 2663 choose "MMConfig", then PCI Express MMCONFIG will be used. 2664 If you choose "Any", the kernel will try MMCONFIG, then the 2665 direct access method and falls back to the BIOS if that doesn't 2666 work. If unsure, go with the default, which is "Any". 2667 2668config PCI_GOBIOS 2669 bool "BIOS" 2670 2671config PCI_GOMMCONFIG 2672 bool "MMConfig" 2673 2674config PCI_GODIRECT 2675 bool "Direct" 2676 2677config PCI_GOOLPC 2678 bool "OLPC XO-1" 2679 depends on OLPC 2680 2681config PCI_GOANY 2682 bool "Any" 2683 2684endchoice 2685 2686config PCI_BIOS 2687 def_bool y 2688 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2689 2690# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2691config PCI_DIRECT 2692 def_bool y 2693 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2694 2695config PCI_MMCONFIG 2696 bool "Support mmconfig PCI config space access" if X86_64 2697 default y 2698 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2699 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2700 2701config PCI_OLPC 2702 def_bool y 2703 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2704 2705config PCI_XEN 2706 def_bool y 2707 depends on PCI && XEN 2708 select SWIOTLB_XEN 2709 2710config MMCONF_FAM10H 2711 def_bool y 2712 depends on X86_64 && PCI_MMCONFIG && ACPI 2713 2714config PCI_CNB20LE_QUIRK 2715 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2716 depends on PCI 2717 help 2718 Read the PCI windows out of the CNB20LE host bridge. This allows 2719 PCI hotplug to work on systems with the CNB20LE chipset which do 2720 not have ACPI. 2721 2722 There's no public spec for this chipset, and this functionality 2723 is known to be incomplete. 2724 2725 You should say N unless you know you need this. 2726 2727config ISA_BUS 2728 bool "ISA bus support on modern systems" if EXPERT 2729 help 2730 Expose ISA bus device drivers and options available for selection and 2731 configuration. Enable this option if your target machine has an ISA 2732 bus. ISA is an older system, displaced by PCI and newer bus 2733 architectures -- if your target machine is modern, it probably does 2734 not have an ISA bus. 2735 2736 If unsure, say N. 2737 2738# x86_64 have no ISA slots, but can have ISA-style DMA. 2739config ISA_DMA_API 2740 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2741 default y 2742 help 2743 Enables ISA-style DMA support for devices requiring such controllers. 2744 If unsure, say Y. 2745 2746if X86_32 2747 2748config ISA 2749 bool "ISA support" 2750 ---help--- 2751 Find out whether you have ISA slots on your motherboard. ISA is the 2752 name of a bus system, i.e. the way the CPU talks to the other stuff 2753 inside your box. Other bus systems are PCI, EISA, MicroChannel 2754 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2755 newer boards don't support it. If you have ISA, say Y, otherwise N. 2756 2757config SCx200 2758 tristate "NatSemi SCx200 support" 2759 ---help--- 2760 This provides basic support for National Semiconductor's 2761 (now AMD's) Geode processors. The driver probes for the 2762 PCI-IDs of several on-chip devices, so its a good dependency 2763 for other scx200_* drivers. 2764 2765 If compiled as a module, the driver is named scx200. 2766 2767config SCx200HR_TIMER 2768 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2769 depends on SCx200 2770 default y 2771 ---help--- 2772 This driver provides a clocksource built upon the on-chip 2773 27MHz high-resolution timer. Its also a workaround for 2774 NSC Geode SC-1100's buggy TSC, which loses time when the 2775 processor goes idle (as is done by the scheduler). The 2776 other workaround is idle=poll boot option. 2777 2778config OLPC 2779 bool "One Laptop Per Child support" 2780 depends on !X86_PAE 2781 select GPIOLIB 2782 select OF 2783 select OF_PROMTREE 2784 select IRQ_DOMAIN 2785 select OLPC_EC 2786 ---help--- 2787 Add support for detecting the unique features of the OLPC 2788 XO hardware. 2789 2790config OLPC_XO1_PM 2791 bool "OLPC XO-1 Power Management" 2792 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2793 ---help--- 2794 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2795 2796config OLPC_XO1_RTC 2797 bool "OLPC XO-1 Real Time Clock" 2798 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2799 ---help--- 2800 Add support for the XO-1 real time clock, which can be used as a 2801 programmable wakeup source. 2802 2803config OLPC_XO1_SCI 2804 bool "OLPC XO-1 SCI extras" 2805 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2806 depends on INPUT=y 2807 select POWER_SUPPLY 2808 ---help--- 2809 Add support for SCI-based features of the OLPC XO-1 laptop: 2810 - EC-driven system wakeups 2811 - Power button 2812 - Ebook switch 2813 - Lid switch 2814 - AC adapter status updates 2815 - Battery status updates 2816 2817config OLPC_XO15_SCI 2818 bool "OLPC XO-1.5 SCI extras" 2819 depends on OLPC && ACPI 2820 select POWER_SUPPLY 2821 ---help--- 2822 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2823 - EC-driven system wakeups 2824 - AC adapter status updates 2825 - Battery status updates 2826 2827config ALIX 2828 bool "PCEngines ALIX System Support (LED setup)" 2829 select GPIOLIB 2830 ---help--- 2831 This option enables system support for the PCEngines ALIX. 2832 At present this just sets up LEDs for GPIO control on 2833 ALIX2/3/6 boards. However, other system specific setup should 2834 get added here. 2835 2836 Note: You must still enable the drivers for GPIO and LED support 2837 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2838 2839 Note: You have to set alix.force=1 for boards with Award BIOS. 2840 2841config NET5501 2842 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2843 select GPIOLIB 2844 ---help--- 2845 This option enables system support for the Soekris Engineering net5501. 2846 2847config GEOS 2848 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2849 select GPIOLIB 2850 depends on DMI 2851 ---help--- 2852 This option enables system support for the Traverse Technologies GEOS. 2853 2854config TS5500 2855 bool "Technologic Systems TS-5500 platform support" 2856 depends on MELAN 2857 select CHECK_SIGNATURE 2858 select NEW_LEDS 2859 select LEDS_CLASS 2860 ---help--- 2861 This option enables system support for the Technologic Systems TS-5500. 2862 2863endif # X86_32 2864 2865config AMD_NB 2866 def_bool y 2867 depends on CPU_SUP_AMD && PCI 2868 2869config X86_SYSFB 2870 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2871 help 2872 Firmwares often provide initial graphics framebuffers so the BIOS, 2873 bootloader or kernel can show basic video-output during boot for 2874 user-guidance and debugging. Historically, x86 used the VESA BIOS 2875 Extensions and EFI-framebuffers for this, which are mostly limited 2876 to x86. 2877 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2878 framebuffers so the new generic system-framebuffer drivers can be 2879 used on x86. If the framebuffer is not compatible with the generic 2880 modes, it is advertised as fallback platform framebuffer so legacy 2881 drivers like efifb, vesafb and uvesafb can pick it up. 2882 If this option is not selected, all system framebuffers are always 2883 marked as fallback platform framebuffers as usual. 2884 2885 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2886 not be able to pick up generic system framebuffers if this option 2887 is selected. You are highly encouraged to enable simplefb as 2888 replacement if you select this option. simplefb can correctly deal 2889 with generic system framebuffers. But you should still keep vesafb 2890 and others enabled as fallback if a system framebuffer is 2891 incompatible with simplefb. 2892 2893 If unsure, say Y. 2894 2895endmenu 2896 2897 2898menu "Binary Emulations" 2899 2900config IA32_EMULATION 2901 bool "IA32 Emulation" 2902 depends on X86_64 2903 select ARCH_WANT_OLD_COMPAT_IPC 2904 select BINFMT_ELF 2905 select COMPAT_BINFMT_ELF 2906 select COMPAT_OLD_SIGACTION 2907 ---help--- 2908 Include code to run legacy 32-bit programs under a 2909 64-bit kernel. You should likely turn this on, unless you're 2910 100% sure that you don't have any 32-bit programs left. 2911 2912config IA32_AOUT 2913 tristate "IA32 a.out support" 2914 depends on IA32_EMULATION 2915 depends on BROKEN 2916 ---help--- 2917 Support old a.out binaries in the 32bit emulation. 2918 2919config X86_X32 2920 bool "x32 ABI for 64-bit mode" 2921 depends on X86_64 2922 ---help--- 2923 Include code to run binaries for the x32 native 32-bit ABI 2924 for 64-bit processors. An x32 process gets access to the 2925 full 64-bit register file and wide data path while leaving 2926 pointers at 32 bits for smaller memory footprint. 2927 2928 You will need a recent binutils (2.22 or later) with 2929 elf32_x86_64 support enabled to compile a kernel with this 2930 option set. 2931 2932config COMPAT_32 2933 def_bool y 2934 depends on IA32_EMULATION || X86_32 2935 select HAVE_UID16 2936 select OLD_SIGSUSPEND3 2937 2938config COMPAT 2939 def_bool y 2940 depends on IA32_EMULATION || X86_X32 2941 2942if COMPAT 2943config COMPAT_FOR_U64_ALIGNMENT 2944 def_bool y 2945 2946config SYSVIPC_COMPAT 2947 def_bool y 2948 depends on SYSVIPC 2949endif 2950 2951endmenu 2952 2953 2954config HAVE_ATOMIC_IOMAP 2955 def_bool y 2956 depends on X86_32 2957 2958config X86_DEV_DMA_OPS 2959 bool 2960 2961source "drivers/firmware/Kconfig" 2962 2963source "arch/x86/kvm/Kconfig" 2964