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 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_REFCOUNT 77 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 78 select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE 79 select ARCH_HAS_SET_MEMORY 80 select ARCH_HAS_SET_DIRECT_MAP 81 select ARCH_HAS_STRICT_KERNEL_RWX 82 select ARCH_HAS_STRICT_MODULE_RWX 83 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 84 select ARCH_HAS_UBSAN_SANITIZE_ALL 85 select ARCH_HAVE_NMI_SAFE_CMPXCHG 86 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 87 select ARCH_MIGHT_HAVE_PC_PARPORT 88 select ARCH_MIGHT_HAVE_PC_SERIO 89 select ARCH_STACKWALK 90 select ARCH_SUPPORTS_ACPI 91 select ARCH_SUPPORTS_ATOMIC_RMW 92 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 93 select ARCH_SUPPORTS_LTO_CLANG if X86_64 94 select ARCH_SUPPORTS_THINLTO if X86_64 95 select ARCH_USE_BUILTIN_BSWAP 96 select ARCH_USE_QUEUED_RWLOCKS 97 select ARCH_USE_QUEUED_SPINLOCKS 98 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 99 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 100 select ARCH_WANT_HUGE_PMD_SHARE 101 select ARCH_WANTS_THP_SWAP if X86_64 102 select BUILDTIME_EXTABLE_SORT 103 select CLKEVT_I8253 104 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 105 select CLOCKSOURCE_WATCHDOG 106 select DCACHE_WORD_ACCESS 107 select EDAC_ATOMIC_SCRUB 108 select EDAC_SUPPORT 109 select GENERIC_CLOCKEVENTS 110 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 111 select GENERIC_CLOCKEVENTS_MIN_ADJUST 112 select GENERIC_CMOS_UPDATE 113 select GENERIC_CPU_AUTOPROBE 114 select GENERIC_CPU_VULNERABILITIES 115 select GENERIC_EARLY_IOREMAP 116 select GENERIC_FIND_FIRST_BIT 117 select GENERIC_IOMAP 118 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 119 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 120 select GENERIC_IRQ_MIGRATION if SMP 121 select GENERIC_IRQ_PROBE 122 select GENERIC_IRQ_RESERVATION_MODE 123 select GENERIC_IRQ_SHOW 124 select GENERIC_PENDING_IRQ if SMP 125 select GENERIC_SMP_IDLE_THREAD 126 select GENERIC_STRNCPY_FROM_USER 127 select GENERIC_STRNLEN_USER 128 select GENERIC_TIME_VSYSCALL 129 select GENERIC_GETTIMEOFDAY 130 select GUP_GET_PTE_LOW_HIGH if X86_PAE 131 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 132 select HAVE_ACPI_APEI if ACPI 133 select HAVE_ACPI_APEI_NMI if ACPI 134 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 135 select HAVE_ARCH_AUDITSYSCALL 136 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 137 select HAVE_ARCH_JUMP_LABEL 138 select HAVE_ARCH_JUMP_LABEL_RELATIVE 139 select HAVE_ARCH_KASAN if X86_64 140 select HAVE_ARCH_KGDB 141 select HAVE_ARCH_MMAP_RND_BITS if MMU 142 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 143 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 144 select HAVE_ARCH_PREL32_RELOCATIONS if !LTO_CLANG 145 select HAVE_ARCH_SECCOMP_FILTER 146 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 147 select HAVE_ARCH_STACKLEAK 148 select HAVE_ARCH_TRACEHOOK 149 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 150 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 151 select HAVE_ARCH_VMAP_STACK if X86_64 152 select HAVE_ARCH_WITHIN_STACK_FRAMES 153 select HAVE_ASM_MODVERSIONS 154 select HAVE_CMPXCHG_DOUBLE 155 select HAVE_CMPXCHG_LOCAL 156 select HAVE_CONTEXT_TRACKING if X86_64 157 select HAVE_COPY_THREAD_TLS 158 select HAVE_C_RECORDMCOUNT 159 select HAVE_DEBUG_KMEMLEAK 160 select HAVE_DMA_CONTIGUOUS 161 select HAVE_DYNAMIC_FTRACE 162 select HAVE_DYNAMIC_FTRACE_WITH_REGS 163 select HAVE_EBPF_JIT 164 select HAVE_EFFICIENT_UNALIGNED_ACCESS 165 select HAVE_EISA 166 select HAVE_EXIT_THREAD 167 select HAVE_FAST_GUP 168 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 169 select HAVE_FTRACE_MCOUNT_RECORD 170 select HAVE_FUNCTION_GRAPH_TRACER 171 select HAVE_FUNCTION_TRACER 172 select HAVE_GCC_PLUGINS 173 select HAVE_HW_BREAKPOINT 174 select HAVE_IDE 175 select HAVE_IOREMAP_PROT 176 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 177 select HAVE_IRQ_TIME_ACCOUNTING 178 select HAVE_KERNEL_BZIP2 179 select HAVE_KERNEL_GZIP 180 select HAVE_KERNEL_LZ4 181 select HAVE_KERNEL_LZMA 182 select HAVE_KERNEL_LZO 183 select HAVE_KERNEL_XZ 184 select HAVE_KPROBES 185 select HAVE_KPROBES_ON_FTRACE 186 select HAVE_FUNCTION_ERROR_INJECTION 187 select HAVE_KRETPROBES 188 select HAVE_KVM 189 select HAVE_LIVEPATCH if X86_64 190 select HAVE_MEMBLOCK_NODE_MAP 191 select HAVE_MIXED_BREAKPOINTS_REGS 192 select HAVE_MOD_ARCH_SPECIFIC 193 select HAVE_MOVE_PMD 194 select HAVE_NMI 195 select HAVE_OPROFILE 196 select HAVE_OPTPROBES 197 select HAVE_PCSPKR_PLATFORM 198 select HAVE_PERF_EVENTS 199 select HAVE_PERF_EVENTS_NMI 200 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 201 select HAVE_PCI 202 select HAVE_PERF_REGS 203 select HAVE_PERF_USER_STACK_DUMP 204 select HAVE_RCU_TABLE_FREE if PARAVIRT 205 select HAVE_REGS_AND_STACK_ACCESS_API 206 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 207 select HAVE_FUNCTION_ARG_ACCESS_API 208 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 209 select HAVE_STACK_VALIDATION if X86_64 && !LTO_CLANG 210 select HAVE_RSEQ 211 select HAVE_SYSCALL_TRACEPOINTS 212 select HAVE_UNSTABLE_SCHED_CLOCK 213 select HAVE_USER_RETURN_NOTIFIER 214 select HAVE_GENERIC_VDSO 215 select HOTPLUG_SMT if SMP 216 select IRQ_FORCED_THREADING 217 select NEED_SG_DMA_LENGTH 218 select PCI_DOMAINS if PCI 219 select PCI_LOCKLESS_CONFIG if PCI 220 select PERF_EVENTS 221 select RTC_LIB 222 select RTC_MC146818_LIB 223 select SPARSE_IRQ 224 select SRCU 225 select SYSCTL_EXCEPTION_TRACE 226 select THREAD_INFO_IN_TASK 227 select USER_STACKTRACE_SUPPORT 228 select VIRT_TO_BUS 229 select X86_FEATURE_NAMES if PROC_FS 230 select PROC_PID_ARCH_STATUS if PROC_FS 231 232config INSTRUCTION_DECODER 233 def_bool y 234 depends on KPROBES || PERF_EVENTS || UPROBES 235 236config OUTPUT_FORMAT 237 string 238 default "elf32-i386" if X86_32 239 default "elf64-x86-64" if X86_64 240 241config ARCH_DEFCONFIG 242 string 243 default "arch/x86/configs/i386_defconfig" if X86_32 244 default "arch/x86/configs/x86_64_defconfig" if X86_64 245 246config LOCKDEP_SUPPORT 247 def_bool y 248 249config STACKTRACE_SUPPORT 250 def_bool y 251 252config MMU 253 def_bool y 254 255config ARCH_MMAP_RND_BITS_MIN 256 default 28 if 64BIT 257 default 8 258 259config ARCH_MMAP_RND_BITS_MAX 260 default 32 if 64BIT 261 default 16 262 263config ARCH_MMAP_RND_COMPAT_BITS_MIN 264 default 8 265 266config ARCH_MMAP_RND_COMPAT_BITS_MAX 267 default 16 268 269config SBUS 270 bool 271 272config GENERIC_ISA_DMA 273 def_bool y 274 depends on ISA_DMA_API 275 276config GENERIC_BUG 277 def_bool y 278 depends on BUG 279 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 280 281config GENERIC_BUG_RELATIVE_POINTERS 282 bool 283 284config ARCH_MAY_HAVE_PC_FDC 285 def_bool y 286 depends on ISA_DMA_API 287 288config GENERIC_CALIBRATE_DELAY 289 def_bool y 290 291config ARCH_HAS_CPU_RELAX 292 def_bool y 293 294config ARCH_HAS_CACHE_LINE_SIZE 295 def_bool y 296 297config ARCH_HAS_FILTER_PGPROT 298 def_bool y 299 300config HAVE_SETUP_PER_CPU_AREA 301 def_bool y 302 303config NEED_PER_CPU_EMBED_FIRST_CHUNK 304 def_bool y 305 306config NEED_PER_CPU_PAGE_FIRST_CHUNK 307 def_bool y 308 309config ARCH_HIBERNATION_POSSIBLE 310 def_bool y 311 312config ARCH_SUSPEND_POSSIBLE 313 def_bool y 314 315config ARCH_WANT_GENERAL_HUGETLB 316 def_bool y 317 318config ZONE_DMA32 319 def_bool y if X86_64 320 321config AUDIT_ARCH 322 def_bool y if X86_64 323 324config ARCH_SUPPORTS_DEBUG_PAGEALLOC 325 def_bool y 326 327config KASAN_SHADOW_OFFSET 328 hex 329 depends on KASAN 330 default 0xdffffc0000000000 331 332config HAVE_INTEL_TXT 333 def_bool y 334 depends on INTEL_IOMMU && ACPI 335 336config X86_32_SMP 337 def_bool y 338 depends on X86_32 && SMP 339 340config X86_64_SMP 341 def_bool y 342 depends on X86_64 && SMP 343 344config X86_32_LAZY_GS 345 def_bool y 346 depends on X86_32 && !STACKPROTECTOR 347 348config ARCH_SUPPORTS_UPROBES 349 def_bool y 350 351config FIX_EARLYCON_MEM 352 def_bool y 353 354config DYNAMIC_PHYSICAL_MASK 355 bool 356 357config PGTABLE_LEVELS 358 int 359 default 5 if X86_5LEVEL 360 default 4 if X86_64 361 default 3 if X86_PAE 362 default 2 363 364config CC_HAS_SANE_STACKPROTECTOR 365 bool 366 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 367 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 368 help 369 We have to make sure stack protector is unconditionally disabled if 370 the compiler produces broken code. 371 372menu "Processor type and features" 373 374config ZONE_DMA 375 bool "DMA memory allocation support" if EXPERT 376 default y 377 help 378 DMA memory allocation support allows devices with less than 32-bit 379 addressing to allocate within the first 16MB of address space. 380 Disable if no such devices will be used. 381 382 If unsure, say Y. 383 384config SMP 385 bool "Symmetric multi-processing support" 386 ---help--- 387 This enables support for systems with more than one CPU. If you have 388 a system with only one CPU, say N. If you have a system with more 389 than one CPU, say Y. 390 391 If you say N here, the kernel will run on uni- and multiprocessor 392 machines, but will use only one CPU of a multiprocessor machine. If 393 you say Y here, the kernel will run on many, but not all, 394 uniprocessor machines. On a uniprocessor machine, the kernel 395 will run faster if you say N here. 396 397 Note that if you say Y here and choose architecture "586" or 398 "Pentium" under "Processor family", the kernel will not work on 486 399 architectures. Similarly, multiprocessor kernels for the "PPro" 400 architecture may not work on all Pentium based boards. 401 402 People using multiprocessor machines who say Y here should also say 403 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 404 Management" code will be disabled if you say Y here. 405 406 See also <file:Documentation/x86/i386/IO-APIC.rst>, 407 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 408 <http://www.tldp.org/docs.html#howto>. 409 410 If you don't know what to do here, say N. 411 412config X86_FEATURE_NAMES 413 bool "Processor feature human-readable names" if EMBEDDED 414 default y 415 ---help--- 416 This option compiles in a table of x86 feature bits and corresponding 417 names. This is required to support /proc/cpuinfo and a few kernel 418 messages. You can disable this to save space, at the expense of 419 making those few kernel messages show numeric feature bits instead. 420 421 If in doubt, say Y. 422 423config X86_X2APIC 424 bool "Support x2apic" 425 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 426 ---help--- 427 This enables x2apic support on CPUs that have this feature. 428 429 This allows 32-bit apic IDs (so it can support very large systems), 430 and accesses the local apic via MSRs not via mmio. 431 432 If you don't know what to do here, say N. 433 434config X86_MPPARSE 435 bool "Enable MPS table" if ACPI || SFI 436 default y 437 depends on X86_LOCAL_APIC 438 ---help--- 439 For old smp systems that do not have proper acpi support. Newer systems 440 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 441 442config GOLDFISH 443 def_bool y 444 depends on X86_GOLDFISH 445 446config RETPOLINE 447 bool "Avoid speculative indirect branches in kernel" 448 default y 449 select STACK_VALIDATION if HAVE_STACK_VALIDATION 450 help 451 Compile kernel with the retpoline compiler options to guard against 452 kernel-to-user data leaks by avoiding speculative indirect 453 branches. Requires a compiler with -mindirect-branch=thunk-extern 454 support for full protection. The kernel may run slower. 455 456config X86_CPU_RESCTRL 457 bool "x86 CPU resource control support" 458 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 459 select KERNFS 460 help 461 Enable x86 CPU resource control support. 462 463 Provide support for the allocation and monitoring of system resources 464 usage by the CPU. 465 466 Intel calls this Intel Resource Director Technology 467 (Intel(R) RDT). More information about RDT can be found in the 468 Intel x86 Architecture Software Developer Manual. 469 470 AMD calls this AMD Platform Quality of Service (AMD QoS). 471 More information about AMD QoS can be found in the AMD64 Technology 472 Platform Quality of Service Extensions manual. 473 474 Say N if unsure. 475 476if X86_32 477config X86_BIGSMP 478 bool "Support for big SMP systems with more than 8 CPUs" 479 depends on SMP 480 ---help--- 481 This option is needed for the systems that have more than 8 CPUs 482 483config X86_EXTENDED_PLATFORM 484 bool "Support for extended (non-PC) x86 platforms" 485 default y 486 ---help--- 487 If you disable this option then the kernel will only support 488 standard PC platforms. (which covers the vast majority of 489 systems out there.) 490 491 If you enable this option then you'll be able to select support 492 for the following (non-PC) 32 bit x86 platforms: 493 Goldfish (Android emulator) 494 AMD Elan 495 RDC R-321x SoC 496 SGI 320/540 (Visual Workstation) 497 STA2X11-based (e.g. Northville) 498 Moorestown MID devices 499 500 If you have one of these systems, or if you want to build a 501 generic distribution kernel, say Y here - otherwise say N. 502endif 503 504if X86_64 505config X86_EXTENDED_PLATFORM 506 bool "Support for extended (non-PC) x86 platforms" 507 default y 508 ---help--- 509 If you disable this option then the kernel will only support 510 standard PC platforms. (which covers the vast majority of 511 systems out there.) 512 513 If you enable this option then you'll be able to select support 514 for the following (non-PC) 64 bit x86 platforms: 515 Numascale NumaChip 516 ScaleMP vSMP 517 SGI Ultraviolet 518 519 If you have one of these systems, or if you want to build a 520 generic distribution kernel, say Y here - otherwise say N. 521endif 522# This is an alphabetically sorted list of 64 bit extended platforms 523# Please maintain the alphabetic order if and when there are additions 524config X86_NUMACHIP 525 bool "Numascale NumaChip" 526 depends on X86_64 527 depends on X86_EXTENDED_PLATFORM 528 depends on NUMA 529 depends on SMP 530 depends on X86_X2APIC 531 depends on PCI_MMCONFIG 532 ---help--- 533 Adds support for Numascale NumaChip large-SMP systems. Needed to 534 enable more than ~168 cores. 535 If you don't have one of these, you should say N here. 536 537config X86_VSMP 538 bool "ScaleMP vSMP" 539 select HYPERVISOR_GUEST 540 select PARAVIRT 541 depends on X86_64 && PCI 542 depends on X86_EXTENDED_PLATFORM 543 depends on SMP 544 ---help--- 545 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 546 supposed to run on these EM64T-based machines. Only choose this option 547 if you have one of these machines. 548 549config X86_UV 550 bool "SGI Ultraviolet" 551 depends on X86_64 552 depends on X86_EXTENDED_PLATFORM 553 depends on NUMA 554 depends on EFI 555 depends on X86_X2APIC 556 depends on PCI 557 ---help--- 558 This option is needed in order to support SGI Ultraviolet systems. 559 If you don't have one of these, you should say N here. 560 561# Following is an alphabetically sorted list of 32 bit extended platforms 562# Please maintain the alphabetic order if and when there are additions 563 564config X86_GOLDFISH 565 bool "Goldfish (Virtual Platform)" 566 depends on X86_EXTENDED_PLATFORM 567 ---help--- 568 Enable support for the Goldfish virtual platform used primarily 569 for Android development. Unless you are building for the Android 570 Goldfish emulator say N here. 571 572config X86_INTEL_CE 573 bool "CE4100 TV platform" 574 depends on PCI 575 depends on PCI_GODIRECT 576 depends on X86_IO_APIC 577 depends on X86_32 578 depends on X86_EXTENDED_PLATFORM 579 select X86_REBOOTFIXUPS 580 select OF 581 select OF_EARLY_FLATTREE 582 ---help--- 583 Select for the Intel CE media processor (CE4100) SOC. 584 This option compiles in support for the CE4100 SOC for settop 585 boxes and media devices. 586 587config X86_INTEL_MID 588 bool "Intel MID platform support" 589 depends on X86_EXTENDED_PLATFORM 590 depends on X86_PLATFORM_DEVICES 591 depends on PCI 592 depends on X86_64 || (PCI_GOANY && X86_32) 593 depends on X86_IO_APIC 594 select SFI 595 select I2C 596 select DW_APB_TIMER 597 select APB_TIMER 598 select INTEL_SCU_IPC 599 select MFD_INTEL_MSIC 600 ---help--- 601 Select to build a kernel capable of supporting Intel MID (Mobile 602 Internet Device) platform systems which do not have the PCI legacy 603 interfaces. If you are building for a PC class system say N here. 604 605 Intel MID platforms are based on an Intel processor and chipset which 606 consume less power than most of the x86 derivatives. 607 608config X86_INTEL_QUARK 609 bool "Intel Quark platform support" 610 depends on X86_32 611 depends on X86_EXTENDED_PLATFORM 612 depends on X86_PLATFORM_DEVICES 613 depends on X86_TSC 614 depends on PCI 615 depends on PCI_GOANY 616 depends on X86_IO_APIC 617 select IOSF_MBI 618 select INTEL_IMR 619 select COMMON_CLK 620 ---help--- 621 Select to include support for Quark X1000 SoC. 622 Say Y here if you have a Quark based system such as the Arduino 623 compatible Intel Galileo. 624 625config X86_INTEL_LPSS 626 bool "Intel Low Power Subsystem Support" 627 depends on X86 && ACPI && PCI 628 select COMMON_CLK 629 select PINCTRL 630 select IOSF_MBI 631 ---help--- 632 Select to build support for Intel Low Power Subsystem such as 633 found on Intel Lynxpoint PCH. Selecting this option enables 634 things like clock tree (common clock framework) and pincontrol 635 which are needed by the LPSS peripheral drivers. 636 637config X86_AMD_PLATFORM_DEVICE 638 bool "AMD ACPI2Platform devices support" 639 depends on ACPI 640 select COMMON_CLK 641 select PINCTRL 642 ---help--- 643 Select to interpret AMD specific ACPI device to platform device 644 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 645 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 646 implemented under PINCTRL subsystem. 647 648config IOSF_MBI 649 tristate "Intel SoC IOSF Sideband support for SoC platforms" 650 depends on PCI 651 ---help--- 652 This option enables sideband register access support for Intel SoC 653 platforms. On these platforms the IOSF sideband is used in lieu of 654 MSR's for some register accesses, mostly but not limited to thermal 655 and power. Drivers may query the availability of this device to 656 determine if they need the sideband in order to work on these 657 platforms. The sideband is available on the following SoC products. 658 This list is not meant to be exclusive. 659 - BayTrail 660 - Braswell 661 - Quark 662 663 You should say Y if you are running a kernel on one of these SoC's. 664 665config IOSF_MBI_DEBUG 666 bool "Enable IOSF sideband access through debugfs" 667 depends on IOSF_MBI && DEBUG_FS 668 ---help--- 669 Select this option to expose the IOSF sideband access registers (MCR, 670 MDR, MCRX) through debugfs to write and read register information from 671 different units on the SoC. This is most useful for obtaining device 672 state information for debug and analysis. As this is a general access 673 mechanism, users of this option would have specific knowledge of the 674 device they want to access. 675 676 If you don't require the option or are in doubt, say N. 677 678config X86_RDC321X 679 bool "RDC R-321x SoC" 680 depends on X86_32 681 depends on X86_EXTENDED_PLATFORM 682 select M486 683 select X86_REBOOTFIXUPS 684 ---help--- 685 This option is needed for RDC R-321x system-on-chip, also known 686 as R-8610-(G). 687 If you don't have one of these chips, you should say N here. 688 689config X86_32_NON_STANDARD 690 bool "Support non-standard 32-bit SMP architectures" 691 depends on X86_32 && SMP 692 depends on X86_EXTENDED_PLATFORM 693 ---help--- 694 This option compiles in the bigsmp and STA2X11 default 695 subarchitectures. It is intended for a generic binary 696 kernel. If you select them all, kernel will probe it one by 697 one and will fallback to default. 698 699# Alphabetically sorted list of Non standard 32 bit platforms 700 701config X86_SUPPORTS_MEMORY_FAILURE 702 def_bool y 703 # MCE code calls memory_failure(): 704 depends on X86_MCE 705 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 706 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 707 depends on X86_64 || !SPARSEMEM 708 select ARCH_SUPPORTS_MEMORY_FAILURE 709 710config STA2X11 711 bool "STA2X11 Companion Chip Support" 712 depends on X86_32_NON_STANDARD && PCI 713 select ARCH_HAS_PHYS_TO_DMA 714 select SWIOTLB 715 select MFD_STA2X11 716 select GPIOLIB 717 ---help--- 718 This adds support for boards based on the STA2X11 IO-Hub, 719 a.k.a. "ConneXt". The chip is used in place of the standard 720 PC chipset, so all "standard" peripherals are missing. If this 721 option is selected the kernel will still be able to boot on 722 standard PC machines. 723 724config X86_32_IRIS 725 tristate "Eurobraille/Iris poweroff module" 726 depends on X86_32 727 ---help--- 728 The Iris machines from EuroBraille do not have APM or ACPI support 729 to shut themselves down properly. A special I/O sequence is 730 needed to do so, which is what this module does at 731 kernel shutdown. 732 733 This is only for Iris machines from EuroBraille. 734 735 If unused, say N. 736 737config SCHED_OMIT_FRAME_POINTER 738 def_bool y 739 prompt "Single-depth WCHAN output" 740 depends on X86 741 ---help--- 742 Calculate simpler /proc/<PID>/wchan values. If this option 743 is disabled then wchan values will recurse back to the 744 caller function. This provides more accurate wchan values, 745 at the expense of slightly more scheduling overhead. 746 747 If in doubt, say "Y". 748 749menuconfig HYPERVISOR_GUEST 750 bool "Linux guest support" 751 ---help--- 752 Say Y here to enable options for running Linux under various hyper- 753 visors. This option enables basic hypervisor detection and platform 754 setup. 755 756 If you say N, all options in this submenu will be skipped and 757 disabled, and Linux guest support won't be built in. 758 759if HYPERVISOR_GUEST 760 761config PARAVIRT 762 bool "Enable paravirtualization code" 763 ---help--- 764 This changes the kernel so it can modify itself when it is run 765 under a hypervisor, potentially improving performance significantly 766 over full virtualization. However, when run without a hypervisor 767 the kernel is theoretically slower and slightly larger. 768 769config PARAVIRT_XXL 770 bool 771 772config PARAVIRT_DEBUG 773 bool "paravirt-ops debugging" 774 depends on PARAVIRT && DEBUG_KERNEL 775 ---help--- 776 Enable to debug paravirt_ops internals. Specifically, BUG if 777 a paravirt_op is missing when it is called. 778 779config PARAVIRT_SPINLOCKS 780 bool "Paravirtualization layer for spinlocks" 781 depends on PARAVIRT && SMP 782 ---help--- 783 Paravirtualized spinlocks allow a pvops backend to replace the 784 spinlock implementation with something virtualization-friendly 785 (for example, block the virtual CPU rather than spinning). 786 787 It has a minimal impact on native kernels and gives a nice performance 788 benefit on paravirtualized KVM / Xen kernels. 789 790 If you are unsure how to answer this question, answer Y. 791 792config X86_HV_CALLBACK_VECTOR 793 def_bool n 794 795source "arch/x86/xen/Kconfig" 796 797config KVM_GUEST 798 bool "KVM Guest support (including kvmclock)" 799 depends on PARAVIRT 800 select PARAVIRT_CLOCK 801 select ARCH_CPUIDLE_HALTPOLL 802 default y 803 ---help--- 804 This option enables various optimizations for running under the KVM 805 hypervisor. It includes a paravirtualized clock, so that instead 806 of relying on a PIT (or probably other) emulation by the 807 underlying device model, the host provides the guest with 808 timing infrastructure such as time of day, and system time 809 810config ARCH_CPUIDLE_HALTPOLL 811 def_bool n 812 prompt "Disable host haltpoll when loading haltpoll driver" 813 help 814 If virtualized under KVM, disable host haltpoll. 815 816config PVH 817 bool "Support for running PVH guests" 818 ---help--- 819 This option enables the PVH entry point for guest virtual machines 820 as specified in the x86/HVM direct boot ABI. 821 822config KVM_DEBUG_FS 823 bool "Enable debug information for KVM Guests in debugfs" 824 depends on KVM_GUEST && DEBUG_FS 825 ---help--- 826 This option enables collection of various statistics for KVM guest. 827 Statistics are displayed in debugfs filesystem. Enabling this option 828 may incur significant overhead. 829 830config PARAVIRT_TIME_ACCOUNTING 831 bool "Paravirtual steal time accounting" 832 depends on PARAVIRT 833 ---help--- 834 Select this option to enable fine granularity task steal time 835 accounting. Time spent executing other tasks in parallel with 836 the current vCPU is discounted from the vCPU power. To account for 837 that, there can be a small performance impact. 838 839 If in doubt, say N here. 840 841config PARAVIRT_CLOCK 842 bool 843 844config JAILHOUSE_GUEST 845 bool "Jailhouse non-root cell support" 846 depends on X86_64 && PCI 847 select X86_PM_TIMER 848 ---help--- 849 This option allows to run Linux as guest in a Jailhouse non-root 850 cell. You can leave this option disabled if you only want to start 851 Jailhouse and run Linux afterwards in the root cell. 852 853config ACRN_GUEST 854 bool "ACRN Guest support" 855 depends on X86_64 856 select X86_HV_CALLBACK_VECTOR 857 help 858 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 859 a flexible, lightweight reference open-source hypervisor, built with 860 real-time and safety-criticality in mind. It is built for embedded 861 IOT with small footprint and real-time features. More details can be 862 found in https://projectacrn.org/. 863 864endif #HYPERVISOR_GUEST 865 866source "arch/x86/Kconfig.cpu" 867 868config HPET_TIMER 869 def_bool X86_64 870 prompt "HPET Timer Support" if X86_32 871 ---help--- 872 Use the IA-PC HPET (High Precision Event Timer) to manage 873 time in preference to the PIT and RTC, if a HPET is 874 present. 875 HPET is the next generation timer replacing legacy 8254s. 876 The HPET provides a stable time base on SMP 877 systems, unlike the TSC, but it is more expensive to access, 878 as it is off-chip. The interface used is documented 879 in the HPET spec, revision 1. 880 881 You can safely choose Y here. However, HPET will only be 882 activated if the platform and the BIOS support this feature. 883 Otherwise the 8254 will be used for timing services. 884 885 Choose N to continue using the legacy 8254 timer. 886 887config HPET_EMULATE_RTC 888 def_bool y 889 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 890 891config APB_TIMER 892 def_bool y if X86_INTEL_MID 893 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 894 select DW_APB_TIMER 895 depends on X86_INTEL_MID && SFI 896 help 897 APB timer is the replacement for 8254, HPET on X86 MID platforms. 898 The APBT provides a stable time base on SMP 899 systems, unlike the TSC, but it is more expensive to access, 900 as it is off-chip. APB timers are always running regardless of CPU 901 C states, they are used as per CPU clockevent device when possible. 902 903# Mark as expert because too many people got it wrong. 904# The code disables itself when not needed. 905config DMI 906 default y 907 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 908 bool "Enable DMI scanning" if EXPERT 909 ---help--- 910 Enabled scanning of DMI to identify machine quirks. Say Y 911 here unless you have verified that your setup is not 912 affected by entries in the DMI blacklist. Required by PNP 913 BIOS code. 914 915config GART_IOMMU 916 bool "Old AMD GART IOMMU support" 917 select IOMMU_HELPER 918 select SWIOTLB 919 depends on X86_64 && PCI && AMD_NB 920 ---help--- 921 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 922 GART based hardware IOMMUs. 923 924 The GART supports full DMA access for devices with 32-bit access 925 limitations, on systems with more than 3 GB. This is usually needed 926 for USB, sound, many IDE/SATA chipsets and some other devices. 927 928 Newer systems typically have a modern AMD IOMMU, supported via 929 the CONFIG_AMD_IOMMU=y config option. 930 931 In normal configurations this driver is only active when needed: 932 there's more than 3 GB of memory and the system contains a 933 32-bit limited device. 934 935 If unsure, say Y. 936 937config CALGARY_IOMMU 938 bool "IBM Calgary IOMMU support" 939 select IOMMU_HELPER 940 select SWIOTLB 941 depends on X86_64 && PCI 942 ---help--- 943 Support for hardware IOMMUs in IBM's xSeries x366 and x460 944 systems. Needed to run systems with more than 3GB of memory 945 properly with 32-bit PCI devices that do not support DAC 946 (Double Address Cycle). Calgary also supports bus level 947 isolation, where all DMAs pass through the IOMMU. This 948 prevents them from going anywhere except their intended 949 destination. This catches hard-to-find kernel bugs and 950 mis-behaving drivers and devices that do not use the DMA-API 951 properly to set up their DMA buffers. The IOMMU can be 952 turned off at boot time with the iommu=off parameter. 953 Normally the kernel will make the right choice by itself. 954 If unsure, say Y. 955 956config CALGARY_IOMMU_ENABLED_BY_DEFAULT 957 def_bool y 958 prompt "Should Calgary be enabled by default?" 959 depends on CALGARY_IOMMU 960 ---help--- 961 Should Calgary be enabled by default? if you choose 'y', Calgary 962 will be used (if it exists). If you choose 'n', Calgary will not be 963 used even if it exists. If you choose 'n' and would like to use 964 Calgary anyway, pass 'iommu=calgary' on the kernel command line. 965 If unsure, say Y. 966 967config MAXSMP 968 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 969 depends on X86_64 && SMP && DEBUG_KERNEL 970 select CPUMASK_OFFSTACK 971 ---help--- 972 Enable maximum number of CPUS and NUMA Nodes for this architecture. 973 If unsure, say N. 974 975# 976# The maximum number of CPUs supported: 977# 978# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 979# and which can be configured interactively in the 980# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 981# 982# The ranges are different on 32-bit and 64-bit kernels, depending on 983# hardware capabilities and scalability features of the kernel. 984# 985# ( If MAXSMP is enabled we just use the highest possible value and disable 986# interactive configuration. ) 987# 988 989config NR_CPUS_RANGE_BEGIN 990 int 991 default NR_CPUS_RANGE_END if MAXSMP 992 default 1 if !SMP 993 default 2 994 995config NR_CPUS_RANGE_END 996 int 997 depends on X86_32 998 default 64 if SMP && X86_BIGSMP 999 default 8 if SMP && !X86_BIGSMP 1000 default 1 if !SMP 1001 1002config NR_CPUS_RANGE_END 1003 int 1004 depends on X86_64 1005 default 8192 if SMP && ( MAXSMP || CPUMASK_OFFSTACK) 1006 default 512 if SMP && (!MAXSMP && !CPUMASK_OFFSTACK) 1007 default 1 if !SMP 1008 1009config NR_CPUS_DEFAULT 1010 int 1011 depends on X86_32 1012 default 32 if X86_BIGSMP 1013 default 8 if SMP 1014 default 1 if !SMP 1015 1016config NR_CPUS_DEFAULT 1017 int 1018 depends on X86_64 1019 default 8192 if MAXSMP 1020 default 64 if SMP 1021 default 1 if !SMP 1022 1023config NR_CPUS 1024 int "Maximum number of CPUs" if SMP && !MAXSMP 1025 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1026 default NR_CPUS_DEFAULT 1027 ---help--- 1028 This allows you to specify the maximum number of CPUs which this 1029 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1030 supported value is 8192, otherwise the maximum value is 512. The 1031 minimum value which makes sense is 2. 1032 1033 This is purely to save memory: each supported CPU adds about 8KB 1034 to the kernel image. 1035 1036config SCHED_SMT 1037 def_bool y if SMP 1038 1039config SCHED_MC 1040 def_bool y 1041 prompt "Multi-core scheduler support" 1042 depends on SMP 1043 ---help--- 1044 Multi-core scheduler support improves the CPU scheduler's decision 1045 making when dealing with multi-core CPU chips at a cost of slightly 1046 increased overhead in some places. If unsure say N here. 1047 1048config SCHED_MC_PRIO 1049 bool "CPU core priorities scheduler support" 1050 depends on SCHED_MC && CPU_SUP_INTEL 1051 select X86_INTEL_PSTATE 1052 select CPU_FREQ 1053 default y 1054 ---help--- 1055 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1056 core ordering determined at manufacturing time, which allows 1057 certain cores to reach higher turbo frequencies (when running 1058 single threaded workloads) than others. 1059 1060 Enabling this kernel feature teaches the scheduler about 1061 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1062 scheduler's CPU selection logic accordingly, so that higher 1063 overall system performance can be achieved. 1064 1065 This feature will have no effect on CPUs without this feature. 1066 1067 If unsure say Y here. 1068 1069config UP_LATE_INIT 1070 def_bool y 1071 depends on !SMP && X86_LOCAL_APIC 1072 1073config X86_UP_APIC 1074 bool "Local APIC support on uniprocessors" if !PCI_MSI 1075 default PCI_MSI 1076 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1077 ---help--- 1078 A local APIC (Advanced Programmable Interrupt Controller) is an 1079 integrated interrupt controller in the CPU. If you have a single-CPU 1080 system which has a processor with a local APIC, you can say Y here to 1081 enable and use it. If you say Y here even though your machine doesn't 1082 have a local APIC, then the kernel will still run with no slowdown at 1083 all. The local APIC supports CPU-generated self-interrupts (timer, 1084 performance counters), and the NMI watchdog which detects hard 1085 lockups. 1086 1087config X86_UP_IOAPIC 1088 bool "IO-APIC support on uniprocessors" 1089 depends on X86_UP_APIC 1090 ---help--- 1091 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1092 SMP-capable replacement for PC-style interrupt controllers. Most 1093 SMP systems and many recent uniprocessor systems have one. 1094 1095 If you have a single-CPU system with an IO-APIC, you can say Y here 1096 to use it. If you say Y here even though your machine doesn't have 1097 an IO-APIC, then the kernel will still run with no slowdown at all. 1098 1099config X86_LOCAL_APIC 1100 def_bool y 1101 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1102 select IRQ_DOMAIN_HIERARCHY 1103 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1104 1105config X86_IO_APIC 1106 def_bool y 1107 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1108 1109config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1110 bool "Reroute for broken boot IRQs" 1111 depends on X86_IO_APIC 1112 ---help--- 1113 This option enables a workaround that fixes a source of 1114 spurious interrupts. This is recommended when threaded 1115 interrupt handling is used on systems where the generation of 1116 superfluous "boot interrupts" cannot be disabled. 1117 1118 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1119 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1120 kernel does during interrupt handling). On chipsets where this 1121 boot IRQ generation cannot be disabled, this workaround keeps 1122 the original IRQ line masked so that only the equivalent "boot 1123 IRQ" is delivered to the CPUs. The workaround also tells the 1124 kernel to set up the IRQ handler on the boot IRQ line. In this 1125 way only one interrupt is delivered to the kernel. Otherwise 1126 the spurious second interrupt may cause the kernel to bring 1127 down (vital) interrupt lines. 1128 1129 Only affects "broken" chipsets. Interrupt sharing may be 1130 increased on these systems. 1131 1132config X86_MCE 1133 bool "Machine Check / overheating reporting" 1134 select GENERIC_ALLOCATOR 1135 default y 1136 ---help--- 1137 Machine Check support allows the processor to notify the 1138 kernel if it detects a problem (e.g. overheating, data corruption). 1139 The action the kernel takes depends on the severity of the problem, 1140 ranging from warning messages to halting the machine. 1141 1142config X86_MCELOG_LEGACY 1143 bool "Support for deprecated /dev/mcelog character device" 1144 depends on X86_MCE 1145 ---help--- 1146 Enable support for /dev/mcelog which is needed by the old mcelog 1147 userspace logging daemon. Consider switching to the new generation 1148 rasdaemon solution. 1149 1150config X86_MCE_INTEL 1151 def_bool y 1152 prompt "Intel MCE features" 1153 depends on X86_MCE && X86_LOCAL_APIC 1154 ---help--- 1155 Additional support for intel specific MCE features such as 1156 the thermal monitor. 1157 1158config X86_MCE_AMD 1159 def_bool y 1160 prompt "AMD MCE features" 1161 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1162 ---help--- 1163 Additional support for AMD specific MCE features such as 1164 the DRAM Error Threshold. 1165 1166config X86_ANCIENT_MCE 1167 bool "Support for old Pentium 5 / WinChip machine checks" 1168 depends on X86_32 && X86_MCE 1169 ---help--- 1170 Include support for machine check handling on old Pentium 5 or WinChip 1171 systems. These typically need to be enabled explicitly on the command 1172 line. 1173 1174config X86_MCE_THRESHOLD 1175 depends on X86_MCE_AMD || X86_MCE_INTEL 1176 def_bool y 1177 1178config X86_MCE_INJECT 1179 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1180 tristate "Machine check injector support" 1181 ---help--- 1182 Provide support for injecting machine checks for testing purposes. 1183 If you don't know what a machine check is and you don't do kernel 1184 QA it is safe to say n. 1185 1186config X86_THERMAL_VECTOR 1187 def_bool y 1188 depends on X86_MCE_INTEL 1189 1190source "arch/x86/events/Kconfig" 1191 1192config X86_LEGACY_VM86 1193 bool "Legacy VM86 support" 1194 depends on X86_32 1195 ---help--- 1196 This option allows user programs to put the CPU into V8086 1197 mode, which is an 80286-era approximation of 16-bit real mode. 1198 1199 Some very old versions of X and/or vbetool require this option 1200 for user mode setting. Similarly, DOSEMU will use it if 1201 available to accelerate real mode DOS programs. However, any 1202 recent version of DOSEMU, X, or vbetool should be fully 1203 functional even without kernel VM86 support, as they will all 1204 fall back to software emulation. Nevertheless, if you are using 1205 a 16-bit DOS program where 16-bit performance matters, vm86 1206 mode might be faster than emulation and you might want to 1207 enable this option. 1208 1209 Note that any app that works on a 64-bit kernel is unlikely to 1210 need this option, as 64-bit kernels don't, and can't, support 1211 V8086 mode. This option is also unrelated to 16-bit protected 1212 mode and is not needed to run most 16-bit programs under Wine. 1213 1214 Enabling this option increases the complexity of the kernel 1215 and slows down exception handling a tiny bit. 1216 1217 If unsure, say N here. 1218 1219config VM86 1220 bool 1221 default X86_LEGACY_VM86 1222 1223config X86_16BIT 1224 bool "Enable support for 16-bit segments" if EXPERT 1225 default y 1226 depends on MODIFY_LDT_SYSCALL 1227 ---help--- 1228 This option is required by programs like Wine to run 16-bit 1229 protected mode legacy code on x86 processors. Disabling 1230 this option saves about 300 bytes on i386, or around 6K text 1231 plus 16K runtime memory on x86-64, 1232 1233config X86_ESPFIX32 1234 def_bool y 1235 depends on X86_16BIT && X86_32 1236 1237config X86_ESPFIX64 1238 def_bool y 1239 depends on X86_16BIT && X86_64 1240 1241config X86_VSYSCALL_EMULATION 1242 bool "Enable vsyscall emulation" if EXPERT 1243 default y 1244 depends on X86_64 1245 ---help--- 1246 This enables emulation of the legacy vsyscall page. Disabling 1247 it is roughly equivalent to booting with vsyscall=none, except 1248 that it will also disable the helpful warning if a program 1249 tries to use a vsyscall. With this option set to N, offending 1250 programs will just segfault, citing addresses of the form 1251 0xffffffffff600?00. 1252 1253 This option is required by many programs built before 2013, and 1254 care should be used even with newer programs if set to N. 1255 1256 Disabling this option saves about 7K of kernel size and 1257 possibly 4K of additional runtime pagetable memory. 1258 1259config TOSHIBA 1260 tristate "Toshiba Laptop support" 1261 depends on X86_32 1262 ---help--- 1263 This adds a driver to safely access the System Management Mode of 1264 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1265 not work on models with a Phoenix BIOS. The System Management Mode 1266 is used to set the BIOS and power saving options on Toshiba portables. 1267 1268 For information on utilities to make use of this driver see the 1269 Toshiba Linux utilities web site at: 1270 <http://www.buzzard.org.uk/toshiba/>. 1271 1272 Say Y if you intend to run this kernel on a Toshiba portable. 1273 Say N otherwise. 1274 1275config I8K 1276 tristate "Dell i8k legacy laptop support" 1277 select HWMON 1278 select SENSORS_DELL_SMM 1279 ---help--- 1280 This option enables legacy /proc/i8k userspace interface in hwmon 1281 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1282 temperature and allows controlling fan speeds of Dell laptops via 1283 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1284 it reports also power and hotkey status. For fan speed control is 1285 needed userspace package i8kutils. 1286 1287 Say Y if you intend to run this kernel on old Dell laptops or want to 1288 use userspace package i8kutils. 1289 Say N otherwise. 1290 1291config X86_REBOOTFIXUPS 1292 bool "Enable X86 board specific fixups for reboot" 1293 depends on X86_32 1294 ---help--- 1295 This enables chipset and/or board specific fixups to be done 1296 in order to get reboot to work correctly. This is only needed on 1297 some combinations of hardware and BIOS. The symptom, for which 1298 this config is intended, is when reboot ends with a stalled/hung 1299 system. 1300 1301 Currently, the only fixup is for the Geode machines using 1302 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1303 1304 Say Y if you want to enable the fixup. Currently, it's safe to 1305 enable this option even if you don't need it. 1306 Say N otherwise. 1307 1308config MICROCODE 1309 bool "CPU microcode loading support" 1310 default y 1311 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1312 select FW_LOADER 1313 ---help--- 1314 If you say Y here, you will be able to update the microcode on 1315 Intel and AMD processors. The Intel support is for the IA32 family, 1316 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1317 AMD support is for families 0x10 and later. You will obviously need 1318 the actual microcode binary data itself which is not shipped with 1319 the Linux kernel. 1320 1321 The preferred method to load microcode from a detached initrd is described 1322 in Documentation/x86/microcode.rst. For that you need to enable 1323 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1324 initrd for microcode blobs. 1325 1326 In addition, you can build the microcode into the kernel. For that you 1327 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1328 config option. 1329 1330config MICROCODE_INTEL 1331 bool "Intel microcode loading support" 1332 depends on MICROCODE 1333 default MICROCODE 1334 select FW_LOADER 1335 ---help--- 1336 This options enables microcode patch loading support for Intel 1337 processors. 1338 1339 For the current Intel microcode data package go to 1340 <https://downloadcenter.intel.com> and search for 1341 'Linux Processor Microcode Data File'. 1342 1343config MICROCODE_AMD 1344 bool "AMD microcode loading support" 1345 depends on MICROCODE 1346 select FW_LOADER 1347 ---help--- 1348 If you select this option, microcode patch loading support for AMD 1349 processors will be enabled. 1350 1351config MICROCODE_OLD_INTERFACE 1352 bool "Ancient loading interface (DEPRECATED)" 1353 default n 1354 depends on MICROCODE 1355 ---help--- 1356 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1357 which was used by userspace tools like iucode_tool and microcode.ctl. 1358 It is inadequate because it runs too late to be able to properly 1359 load microcode on a machine and it needs special tools. Instead, you 1360 should've switched to the early loading method with the initrd or 1361 builtin microcode by now: Documentation/x86/microcode.rst 1362 1363config X86_MSR 1364 tristate "/dev/cpu/*/msr - Model-specific register support" 1365 ---help--- 1366 This device gives privileged processes access to the x86 1367 Model-Specific Registers (MSRs). It is a character device with 1368 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1369 MSR accesses are directed to a specific CPU on multi-processor 1370 systems. 1371 1372config X86_CPUID 1373 tristate "/dev/cpu/*/cpuid - CPU information support" 1374 ---help--- 1375 This device gives processes access to the x86 CPUID instruction to 1376 be executed on a specific processor. It is a character device 1377 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1378 /dev/cpu/31/cpuid. 1379 1380choice 1381 prompt "High Memory Support" 1382 default HIGHMEM4G 1383 depends on X86_32 1384 1385config NOHIGHMEM 1386 bool "off" 1387 ---help--- 1388 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1389 However, the address space of 32-bit x86 processors is only 4 1390 Gigabytes large. That means that, if you have a large amount of 1391 physical memory, not all of it can be "permanently mapped" by the 1392 kernel. The physical memory that's not permanently mapped is called 1393 "high memory". 1394 1395 If you are compiling a kernel which will never run on a machine with 1396 more than 1 Gigabyte total physical RAM, answer "off" here (default 1397 choice and suitable for most users). This will result in a "3GB/1GB" 1398 split: 3GB are mapped so that each process sees a 3GB virtual memory 1399 space and the remaining part of the 4GB virtual memory space is used 1400 by the kernel to permanently map as much physical memory as 1401 possible. 1402 1403 If the machine has between 1 and 4 Gigabytes physical RAM, then 1404 answer "4GB" here. 1405 1406 If more than 4 Gigabytes is used then answer "64GB" here. This 1407 selection turns Intel PAE (Physical Address Extension) mode on. 1408 PAE implements 3-level paging on IA32 processors. PAE is fully 1409 supported by Linux, PAE mode is implemented on all recent Intel 1410 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1411 then the kernel will not boot on CPUs that don't support PAE! 1412 1413 The actual amount of total physical memory will either be 1414 auto detected or can be forced by using a kernel command line option 1415 such as "mem=256M". (Try "man bootparam" or see the documentation of 1416 your boot loader (lilo or loadlin) about how to pass options to the 1417 kernel at boot time.) 1418 1419 If unsure, say "off". 1420 1421config HIGHMEM4G 1422 bool "4GB" 1423 ---help--- 1424 Select this if you have a 32-bit processor and between 1 and 4 1425 gigabytes of physical RAM. 1426 1427config HIGHMEM64G 1428 bool "64GB" 1429 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1430 select X86_PAE 1431 ---help--- 1432 Select this if you have a 32-bit processor and more than 4 1433 gigabytes of physical RAM. 1434 1435endchoice 1436 1437choice 1438 prompt "Memory split" if EXPERT 1439 default VMSPLIT_3G 1440 depends on X86_32 1441 ---help--- 1442 Select the desired split between kernel and user memory. 1443 1444 If the address range available to the kernel is less than the 1445 physical memory installed, the remaining memory will be available 1446 as "high memory". Accessing high memory is a little more costly 1447 than low memory, as it needs to be mapped into the kernel first. 1448 Note that increasing the kernel address space limits the range 1449 available to user programs, making the address space there 1450 tighter. Selecting anything other than the default 3G/1G split 1451 will also likely make your kernel incompatible with binary-only 1452 kernel modules. 1453 1454 If you are not absolutely sure what you are doing, leave this 1455 option alone! 1456 1457 config VMSPLIT_3G 1458 bool "3G/1G user/kernel split" 1459 config VMSPLIT_3G_OPT 1460 depends on !X86_PAE 1461 bool "3G/1G user/kernel split (for full 1G low memory)" 1462 config VMSPLIT_2G 1463 bool "2G/2G user/kernel split" 1464 config VMSPLIT_2G_OPT 1465 depends on !X86_PAE 1466 bool "2G/2G user/kernel split (for full 2G low memory)" 1467 config VMSPLIT_1G 1468 bool "1G/3G user/kernel split" 1469endchoice 1470 1471config PAGE_OFFSET 1472 hex 1473 default 0xB0000000 if VMSPLIT_3G_OPT 1474 default 0x80000000 if VMSPLIT_2G 1475 default 0x78000000 if VMSPLIT_2G_OPT 1476 default 0x40000000 if VMSPLIT_1G 1477 default 0xC0000000 1478 depends on X86_32 1479 1480config HIGHMEM 1481 def_bool y 1482 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1483 1484config X86_PAE 1485 bool "PAE (Physical Address Extension) Support" 1486 depends on X86_32 && !HIGHMEM4G 1487 select PHYS_ADDR_T_64BIT 1488 select SWIOTLB 1489 ---help--- 1490 PAE is required for NX support, and furthermore enables 1491 larger swapspace support for non-overcommit purposes. It 1492 has the cost of more pagetable lookup overhead, and also 1493 consumes more pagetable space per process. 1494 1495config X86_5LEVEL 1496 bool "Enable 5-level page tables support" 1497 select DYNAMIC_MEMORY_LAYOUT 1498 select SPARSEMEM_VMEMMAP 1499 depends on X86_64 1500 ---help--- 1501 5-level paging enables access to larger address space: 1502 upto 128 PiB of virtual address space and 4 PiB of 1503 physical address space. 1504 1505 It will be supported by future Intel CPUs. 1506 1507 A kernel with the option enabled can be booted on machines that 1508 support 4- or 5-level paging. 1509 1510 See Documentation/x86/x86_64/5level-paging.rst for more 1511 information. 1512 1513 Say N if unsure. 1514 1515config X86_DIRECT_GBPAGES 1516 def_bool y 1517 depends on X86_64 1518 ---help--- 1519 Certain kernel features effectively disable kernel 1520 linear 1 GB mappings (even if the CPU otherwise 1521 supports them), so don't confuse the user by printing 1522 that we have them enabled. 1523 1524config X86_CPA_STATISTICS 1525 bool "Enable statistic for Change Page Attribute" 1526 depends on DEBUG_FS 1527 ---help--- 1528 Expose statistics about the Change Page Attribute mechanims, which 1529 helps to determine the effectiveness of preserving large and huge 1530 page mappings when mapping protections are changed. 1531 1532config AMD_MEM_ENCRYPT 1533 bool "AMD Secure Memory Encryption (SME) support" 1534 depends on X86_64 && CPU_SUP_AMD 1535 select DYNAMIC_PHYSICAL_MASK 1536 select ARCH_USE_MEMREMAP_PROT 1537 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1538 ---help--- 1539 Say yes to enable support for the encryption of system memory. 1540 This requires an AMD processor that supports Secure Memory 1541 Encryption (SME). 1542 1543config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1544 bool "Activate AMD Secure Memory Encryption (SME) by default" 1545 default y 1546 depends on AMD_MEM_ENCRYPT 1547 ---help--- 1548 Say yes to have system memory encrypted by default if running on 1549 an AMD processor that supports Secure Memory Encryption (SME). 1550 1551 If set to Y, then the encryption of system memory can be 1552 deactivated with the mem_encrypt=off command line option. 1553 1554 If set to N, then the encryption of system memory can be 1555 activated with the mem_encrypt=on command line option. 1556 1557# Common NUMA Features 1558config NUMA 1559 bool "Numa Memory Allocation and Scheduler Support" 1560 depends on SMP 1561 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1562 default y if X86_BIGSMP 1563 ---help--- 1564 Enable NUMA (Non Uniform Memory Access) support. 1565 1566 The kernel will try to allocate memory used by a CPU on the 1567 local memory controller of the CPU and add some more 1568 NUMA awareness to the kernel. 1569 1570 For 64-bit this is recommended if the system is Intel Core i7 1571 (or later), AMD Opteron, or EM64T NUMA. 1572 1573 For 32-bit this is only needed if you boot a 32-bit 1574 kernel on a 64-bit NUMA platform. 1575 1576 Otherwise, you should say N. 1577 1578config AMD_NUMA 1579 def_bool y 1580 prompt "Old style AMD Opteron NUMA detection" 1581 depends on X86_64 && NUMA && PCI 1582 ---help--- 1583 Enable AMD NUMA node topology detection. You should say Y here if 1584 you have a multi processor AMD system. This uses an old method to 1585 read the NUMA configuration directly from the builtin Northbridge 1586 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1587 which also takes priority if both are compiled in. 1588 1589config X86_64_ACPI_NUMA 1590 def_bool y 1591 prompt "ACPI NUMA detection" 1592 depends on X86_64 && NUMA && ACPI && PCI 1593 select ACPI_NUMA 1594 ---help--- 1595 Enable ACPI SRAT based node topology detection. 1596 1597# Some NUMA nodes have memory ranges that span 1598# other nodes. Even though a pfn is valid and 1599# between a node's start and end pfns, it may not 1600# reside on that node. See memmap_init_zone() 1601# for details. 1602config NODES_SPAN_OTHER_NODES 1603 def_bool y 1604 depends on X86_64_ACPI_NUMA 1605 1606config NUMA_EMU 1607 bool "NUMA emulation" 1608 depends on NUMA 1609 ---help--- 1610 Enable NUMA emulation. A flat machine will be split 1611 into virtual nodes when booted with "numa=fake=N", where N is the 1612 number of nodes. This is only useful for debugging. 1613 1614config NODES_SHIFT 1615 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1616 range 1 10 1617 default "10" if MAXSMP 1618 default "6" if X86_64 1619 default "3" 1620 depends on NEED_MULTIPLE_NODES 1621 ---help--- 1622 Specify the maximum number of NUMA Nodes available on the target 1623 system. Increases memory reserved to accommodate various tables. 1624 1625config ARCH_HAVE_MEMORY_PRESENT 1626 def_bool y 1627 depends on X86_32 && DISCONTIGMEM 1628 1629config ARCH_FLATMEM_ENABLE 1630 def_bool y 1631 depends on X86_32 && !NUMA 1632 1633config ARCH_DISCONTIGMEM_ENABLE 1634 def_bool n 1635 depends on NUMA && X86_32 1636 depends on BROKEN 1637 1638config ARCH_SPARSEMEM_ENABLE 1639 def_bool y 1640 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1641 select SPARSEMEM_STATIC if X86_32 1642 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1643 1644config ARCH_SPARSEMEM_DEFAULT 1645 def_bool X86_64 || (NUMA && X86_32) 1646 1647config ARCH_SELECT_MEMORY_MODEL 1648 def_bool y 1649 depends on ARCH_SPARSEMEM_ENABLE 1650 1651config ARCH_MEMORY_PROBE 1652 bool "Enable sysfs memory/probe interface" 1653 depends on X86_64 && MEMORY_HOTPLUG 1654 help 1655 This option enables a sysfs memory/probe interface for testing. 1656 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1657 If you are unsure how to answer this question, answer N. 1658 1659config ARCH_PROC_KCORE_TEXT 1660 def_bool y 1661 depends on X86_64 && PROC_KCORE 1662 1663config ILLEGAL_POINTER_VALUE 1664 hex 1665 default 0 if X86_32 1666 default 0xdead000000000000 if X86_64 1667 1668config X86_PMEM_LEGACY_DEVICE 1669 bool 1670 1671config X86_PMEM_LEGACY 1672 tristate "Support non-standard NVDIMMs and ADR protected memory" 1673 depends on PHYS_ADDR_T_64BIT 1674 depends on BLK_DEV 1675 select X86_PMEM_LEGACY_DEVICE 1676 select LIBNVDIMM 1677 help 1678 Treat memory marked using the non-standard e820 type of 12 as used 1679 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1680 The kernel will offer these regions to the 'pmem' driver so 1681 they can be used for persistent storage. 1682 1683 Say Y if unsure. 1684 1685config HIGHPTE 1686 bool "Allocate 3rd-level pagetables from highmem" 1687 depends on HIGHMEM 1688 ---help--- 1689 The VM uses one page table entry for each page of physical memory. 1690 For systems with a lot of RAM, this can be wasteful of precious 1691 low memory. Setting this option will put user-space page table 1692 entries in high memory. 1693 1694config X86_CHECK_BIOS_CORRUPTION 1695 bool "Check for low memory corruption" 1696 ---help--- 1697 Periodically check for memory corruption in low memory, which 1698 is suspected to be caused by BIOS. Even when enabled in the 1699 configuration, it is disabled at runtime. Enable it by 1700 setting "memory_corruption_check=1" on the kernel command 1701 line. By default it scans the low 64k of memory every 60 1702 seconds; see the memory_corruption_check_size and 1703 memory_corruption_check_period parameters in 1704 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1705 1706 When enabled with the default parameters, this option has 1707 almost no overhead, as it reserves a relatively small amount 1708 of memory and scans it infrequently. It both detects corruption 1709 and prevents it from affecting the running system. 1710 1711 It is, however, intended as a diagnostic tool; if repeatable 1712 BIOS-originated corruption always affects the same memory, 1713 you can use memmap= to prevent the kernel from using that 1714 memory. 1715 1716config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1717 bool "Set the default setting of memory_corruption_check" 1718 depends on X86_CHECK_BIOS_CORRUPTION 1719 default y 1720 ---help--- 1721 Set whether the default state of memory_corruption_check is 1722 on or off. 1723 1724config X86_RESERVE_LOW 1725 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1726 default 64 1727 range 4 640 1728 ---help--- 1729 Specify the amount of low memory to reserve for the BIOS. 1730 1731 The first page contains BIOS data structures that the kernel 1732 must not use, so that page must always be reserved. 1733 1734 By default we reserve the first 64K of physical RAM, as a 1735 number of BIOSes are known to corrupt that memory range 1736 during events such as suspend/resume or monitor cable 1737 insertion, so it must not be used by the kernel. 1738 1739 You can set this to 4 if you are absolutely sure that you 1740 trust the BIOS to get all its memory reservations and usages 1741 right. If you know your BIOS have problems beyond the 1742 default 64K area, you can set this to 640 to avoid using the 1743 entire low memory range. 1744 1745 If you have doubts about the BIOS (e.g. suspend/resume does 1746 not work or there's kernel crashes after certain hardware 1747 hotplug events) then you might want to enable 1748 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1749 typical corruption patterns. 1750 1751 Leave this to the default value of 64 if you are unsure. 1752 1753config MATH_EMULATION 1754 bool 1755 depends on MODIFY_LDT_SYSCALL 1756 prompt "Math emulation" if X86_32 1757 ---help--- 1758 Linux can emulate a math coprocessor (used for floating point 1759 operations) if you don't have one. 486DX and Pentium processors have 1760 a math coprocessor built in, 486SX and 386 do not, unless you added 1761 a 487DX or 387, respectively. (The messages during boot time can 1762 give you some hints here ["man dmesg"].) Everyone needs either a 1763 coprocessor or this emulation. 1764 1765 If you don't have a math coprocessor, you need to say Y here; if you 1766 say Y here even though you have a coprocessor, the coprocessor will 1767 be used nevertheless. (This behavior can be changed with the kernel 1768 command line option "no387", which comes handy if your coprocessor 1769 is broken. Try "man bootparam" or see the documentation of your boot 1770 loader (lilo or loadlin) about how to pass options to the kernel at 1771 boot time.) This means that it is a good idea to say Y here if you 1772 intend to use this kernel on different machines. 1773 1774 More information about the internals of the Linux math coprocessor 1775 emulation can be found in <file:arch/x86/math-emu/README>. 1776 1777 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1778 kernel, it won't hurt. 1779 1780config MTRR 1781 def_bool y 1782 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1783 ---help--- 1784 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1785 the Memory Type Range Registers (MTRRs) may be used to control 1786 processor access to memory ranges. This is most useful if you have 1787 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1788 allows bus write transfers to be combined into a larger transfer 1789 before bursting over the PCI/AGP bus. This can increase performance 1790 of image write operations 2.5 times or more. Saying Y here creates a 1791 /proc/mtrr file which may be used to manipulate your processor's 1792 MTRRs. Typically the X server should use this. 1793 1794 This code has a reasonably generic interface so that similar 1795 control registers on other processors can be easily supported 1796 as well: 1797 1798 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1799 Registers (ARRs) which provide a similar functionality to MTRRs. For 1800 these, the ARRs are used to emulate the MTRRs. 1801 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1802 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1803 write-combining. All of these processors are supported by this code 1804 and it makes sense to say Y here if you have one of them. 1805 1806 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1807 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1808 can lead to all sorts of problems, so it's good to say Y here. 1809 1810 You can safely say Y even if your machine doesn't have MTRRs, you'll 1811 just add about 9 KB to your kernel. 1812 1813 See <file:Documentation/x86/mtrr.rst> for more information. 1814 1815config MTRR_SANITIZER 1816 def_bool y 1817 prompt "MTRR cleanup support" 1818 depends on MTRR 1819 ---help--- 1820 Convert MTRR layout from continuous to discrete, so X drivers can 1821 add writeback entries. 1822 1823 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1824 The largest mtrr entry size for a continuous block can be set with 1825 mtrr_chunk_size. 1826 1827 If unsure, say Y. 1828 1829config MTRR_SANITIZER_ENABLE_DEFAULT 1830 int "MTRR cleanup enable value (0-1)" 1831 range 0 1 1832 default "0" 1833 depends on MTRR_SANITIZER 1834 ---help--- 1835 Enable mtrr cleanup default value 1836 1837config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1838 int "MTRR cleanup spare reg num (0-7)" 1839 range 0 7 1840 default "1" 1841 depends on MTRR_SANITIZER 1842 ---help--- 1843 mtrr cleanup spare entries default, it can be changed via 1844 mtrr_spare_reg_nr=N on the kernel command line. 1845 1846config X86_PAT 1847 def_bool y 1848 prompt "x86 PAT support" if EXPERT 1849 depends on MTRR 1850 ---help--- 1851 Use PAT attributes to setup page level cache control. 1852 1853 PATs are the modern equivalents of MTRRs and are much more 1854 flexible than MTRRs. 1855 1856 Say N here if you see bootup problems (boot crash, boot hang, 1857 spontaneous reboots) or a non-working video driver. 1858 1859 If unsure, say Y. 1860 1861config ARCH_USES_PG_UNCACHED 1862 def_bool y 1863 depends on X86_PAT 1864 1865config ARCH_RANDOM 1866 def_bool y 1867 prompt "x86 architectural random number generator" if EXPERT 1868 ---help--- 1869 Enable the x86 architectural RDRAND instruction 1870 (Intel Bull Mountain technology) to generate random numbers. 1871 If supported, this is a high bandwidth, cryptographically 1872 secure hardware random number generator. 1873 1874config X86_SMAP 1875 def_bool y 1876 prompt "Supervisor Mode Access Prevention" if EXPERT 1877 ---help--- 1878 Supervisor Mode Access Prevention (SMAP) is a security 1879 feature in newer Intel processors. There is a small 1880 performance cost if this enabled and turned on; there is 1881 also a small increase in the kernel size if this is enabled. 1882 1883 If unsure, say Y. 1884 1885config X86_INTEL_UMIP 1886 def_bool y 1887 depends on CPU_SUP_INTEL 1888 prompt "Intel User Mode Instruction Prevention" if EXPERT 1889 ---help--- 1890 The User Mode Instruction Prevention (UMIP) is a security 1891 feature in newer Intel processors. If enabled, a general 1892 protection fault is issued if the SGDT, SLDT, SIDT, SMSW 1893 or STR instructions are executed in user mode. These instructions 1894 unnecessarily expose information about the hardware state. 1895 1896 The vast majority of applications do not use these instructions. 1897 For the very few that do, software emulation is provided in 1898 specific cases in protected and virtual-8086 modes. Emulated 1899 results are dummy. 1900 1901config X86_INTEL_MPX 1902 prompt "Intel MPX (Memory Protection Extensions)" 1903 def_bool n 1904 # Note: only available in 64-bit mode due to VMA flags shortage 1905 depends on CPU_SUP_INTEL && X86_64 1906 select ARCH_USES_HIGH_VMA_FLAGS 1907 ---help--- 1908 MPX provides hardware features that can be used in 1909 conjunction with compiler-instrumented code to check 1910 memory references. It is designed to detect buffer 1911 overflow or underflow bugs. 1912 1913 This option enables running applications which are 1914 instrumented or otherwise use MPX. It does not use MPX 1915 itself inside the kernel or to protect the kernel 1916 against bad memory references. 1917 1918 Enabling this option will make the kernel larger: 1919 ~8k of kernel text and 36 bytes of data on a 64-bit 1920 defconfig. It adds a long to the 'mm_struct' which 1921 will increase the kernel memory overhead of each 1922 process and adds some branches to paths used during 1923 exec() and munmap(). 1924 1925 For details, see Documentation/x86/intel_mpx.rst 1926 1927 If unsure, say N. 1928 1929config X86_INTEL_MEMORY_PROTECTION_KEYS 1930 prompt "Intel Memory Protection Keys" 1931 def_bool y 1932 # Note: only available in 64-bit mode 1933 depends on CPU_SUP_INTEL && X86_64 1934 select ARCH_USES_HIGH_VMA_FLAGS 1935 select ARCH_HAS_PKEYS 1936 ---help--- 1937 Memory Protection Keys provides a mechanism for enforcing 1938 page-based protections, but without requiring modification of the 1939 page tables when an application changes protection domains. 1940 1941 For details, see Documentation/core-api/protection-keys.rst 1942 1943 If unsure, say y. 1944 1945choice 1946 prompt "TSX enable mode" 1947 depends on CPU_SUP_INTEL 1948 default X86_INTEL_TSX_MODE_OFF 1949 help 1950 Intel's TSX (Transactional Synchronization Extensions) feature 1951 allows to optimize locking protocols through lock elision which 1952 can lead to a noticeable performance boost. 1953 1954 On the other hand it has been shown that TSX can be exploited 1955 to form side channel attacks (e.g. TAA) and chances are there 1956 will be more of those attacks discovered in the future. 1957 1958 Therefore TSX is not enabled by default (aka tsx=off). An admin 1959 might override this decision by tsx=on the command line parameter. 1960 Even with TSX enabled, the kernel will attempt to enable the best 1961 possible TAA mitigation setting depending on the microcode available 1962 for the particular machine. 1963 1964 This option allows to set the default tsx mode between tsx=on, =off 1965 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1966 details. 1967 1968 Say off if not sure, auto if TSX is in use but it should be used on safe 1969 platforms or on if TSX is in use and the security aspect of tsx is not 1970 relevant. 1971 1972config X86_INTEL_TSX_MODE_OFF 1973 bool "off" 1974 help 1975 TSX is disabled if possible - equals to tsx=off command line parameter. 1976 1977config X86_INTEL_TSX_MODE_ON 1978 bool "on" 1979 help 1980 TSX is always enabled on TSX capable HW - equals the tsx=on command 1981 line parameter. 1982 1983config X86_INTEL_TSX_MODE_AUTO 1984 bool "auto" 1985 help 1986 TSX is enabled on TSX capable HW that is believed to be safe against 1987 side channel attacks- equals the tsx=auto command line parameter. 1988endchoice 1989 1990config EFI 1991 bool "EFI runtime service support" 1992 depends on ACPI 1993 select UCS2_STRING 1994 select EFI_RUNTIME_WRAPPERS 1995 ---help--- 1996 This enables the kernel to use EFI runtime services that are 1997 available (such as the EFI variable services). 1998 1999 This option is only useful on systems that have EFI firmware. 2000 In addition, you should use the latest ELILO loader available 2001 at <http://elilo.sourceforge.net> in order to take advantage 2002 of EFI runtime services. However, even with this option, the 2003 resultant kernel should continue to boot on existing non-EFI 2004 platforms. 2005 2006config EFI_STUB 2007 bool "EFI stub support" 2008 depends on EFI && !X86_USE_3DNOW 2009 select RELOCATABLE 2010 ---help--- 2011 This kernel feature allows a bzImage to be loaded directly 2012 by EFI firmware without the use of a bootloader. 2013 2014 See Documentation/admin-guide/efi-stub.rst for more information. 2015 2016config EFI_MIXED 2017 bool "EFI mixed-mode support" 2018 depends on EFI_STUB && X86_64 2019 ---help--- 2020 Enabling this feature allows a 64-bit kernel to be booted 2021 on a 32-bit firmware, provided that your CPU supports 64-bit 2022 mode. 2023 2024 Note that it is not possible to boot a mixed-mode enabled 2025 kernel via the EFI boot stub - a bootloader that supports 2026 the EFI handover protocol must be used. 2027 2028 If unsure, say N. 2029 2030config SECCOMP 2031 def_bool y 2032 prompt "Enable seccomp to safely compute untrusted bytecode" 2033 ---help--- 2034 This kernel feature is useful for number crunching applications 2035 that may need to compute untrusted bytecode during their 2036 execution. By using pipes or other transports made available to 2037 the process as file descriptors supporting the read/write 2038 syscalls, it's possible to isolate those applications in 2039 their own address space using seccomp. Once seccomp is 2040 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 2041 and the task is only allowed to execute a few safe syscalls 2042 defined by each seccomp mode. 2043 2044 If unsure, say Y. Only embedded should say N here. 2045 2046source "kernel/Kconfig.hz" 2047 2048config KEXEC 2049 bool "kexec system call" 2050 select KEXEC_CORE 2051 ---help--- 2052 kexec is a system call that implements the ability to shutdown your 2053 current kernel, and to start another kernel. It is like a reboot 2054 but it is independent of the system firmware. And like a reboot 2055 you can start any kernel with it, not just Linux. 2056 2057 The name comes from the similarity to the exec system call. 2058 2059 It is an ongoing process to be certain the hardware in a machine 2060 is properly shutdown, so do not be surprised if this code does not 2061 initially work for you. As of this writing the exact hardware 2062 interface is strongly in flux, so no good recommendation can be 2063 made. 2064 2065config KEXEC_FILE 2066 bool "kexec file based system call" 2067 select KEXEC_CORE 2068 select BUILD_BIN2C 2069 depends on X86_64 2070 depends on CRYPTO=y 2071 depends on CRYPTO_SHA256=y 2072 ---help--- 2073 This is new version of kexec system call. This system call is 2074 file based and takes file descriptors as system call argument 2075 for kernel and initramfs as opposed to list of segments as 2076 accepted by previous system call. 2077 2078config ARCH_HAS_KEXEC_PURGATORY 2079 def_bool KEXEC_FILE 2080 2081config KEXEC_SIG 2082 bool "Verify kernel signature during kexec_file_load() syscall" 2083 depends on KEXEC_FILE 2084 ---help--- 2085 2086 This option makes the kexec_file_load() syscall check for a valid 2087 signature of the kernel image. The image can still be loaded without 2088 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2089 there's a signature that we can check, then it must be valid. 2090 2091 In addition to this option, you need to enable signature 2092 verification for the corresponding kernel image type being 2093 loaded in order for this to work. 2094 2095config KEXEC_SIG_FORCE 2096 bool "Require a valid signature in kexec_file_load() syscall" 2097 depends on KEXEC_SIG 2098 ---help--- 2099 This option makes kernel signature verification mandatory for 2100 the kexec_file_load() syscall. 2101 2102config KEXEC_BZIMAGE_VERIFY_SIG 2103 bool "Enable bzImage signature verification support" 2104 depends on KEXEC_SIG 2105 depends on SIGNED_PE_FILE_VERIFICATION 2106 select SYSTEM_TRUSTED_KEYRING 2107 ---help--- 2108 Enable bzImage signature verification support. 2109 2110config CRASH_DUMP 2111 bool "kernel crash dumps" 2112 depends on X86_64 || (X86_32 && HIGHMEM) 2113 ---help--- 2114 Generate crash dump after being started by kexec. 2115 This should be normally only set in special crash dump kernels 2116 which are loaded in the main kernel with kexec-tools into 2117 a specially reserved region and then later executed after 2118 a crash by kdump/kexec. The crash dump kernel must be compiled 2119 to a memory address not used by the main kernel or BIOS using 2120 PHYSICAL_START, or it must be built as a relocatable image 2121 (CONFIG_RELOCATABLE=y). 2122 For more details see Documentation/admin-guide/kdump/kdump.rst 2123 2124config KEXEC_JUMP 2125 bool "kexec jump" 2126 depends on KEXEC && HIBERNATION 2127 ---help--- 2128 Jump between original kernel and kexeced kernel and invoke 2129 code in physical address mode via KEXEC 2130 2131config PHYSICAL_START 2132 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2133 default "0x1000000" 2134 ---help--- 2135 This gives the physical address where the kernel is loaded. 2136 2137 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2138 bzImage will decompress itself to above physical address and 2139 run from there. Otherwise, bzImage will run from the address where 2140 it has been loaded by the boot loader and will ignore above physical 2141 address. 2142 2143 In normal kdump cases one does not have to set/change this option 2144 as now bzImage can be compiled as a completely relocatable image 2145 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2146 address. This option is mainly useful for the folks who don't want 2147 to use a bzImage for capturing the crash dump and want to use a 2148 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2149 to be specifically compiled to run from a specific memory area 2150 (normally a reserved region) and this option comes handy. 2151 2152 So if you are using bzImage for capturing the crash dump, 2153 leave the value here unchanged to 0x1000000 and set 2154 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2155 for capturing the crash dump change this value to start of 2156 the reserved region. In other words, it can be set based on 2157 the "X" value as specified in the "crashkernel=YM@XM" 2158 command line boot parameter passed to the panic-ed 2159 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2160 for more details about crash dumps. 2161 2162 Usage of bzImage for capturing the crash dump is recommended as 2163 one does not have to build two kernels. Same kernel can be used 2164 as production kernel and capture kernel. Above option should have 2165 gone away after relocatable bzImage support is introduced. But it 2166 is present because there are users out there who continue to use 2167 vmlinux for dump capture. This option should go away down the 2168 line. 2169 2170 Don't change this unless you know what you are doing. 2171 2172config RELOCATABLE 2173 bool "Build a relocatable kernel" 2174 default y 2175 ---help--- 2176 This builds a kernel image that retains relocation information 2177 so it can be loaded someplace besides the default 1MB. 2178 The relocations tend to make the kernel binary about 10% larger, 2179 but are discarded at runtime. 2180 2181 One use is for the kexec on panic case where the recovery kernel 2182 must live at a different physical address than the primary 2183 kernel. 2184 2185 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2186 it has been loaded at and the compile time physical address 2187 (CONFIG_PHYSICAL_START) is used as the minimum location. 2188 2189config RANDOMIZE_BASE 2190 bool "Randomize the address of the kernel image (KASLR)" 2191 depends on RELOCATABLE 2192 default y 2193 ---help--- 2194 In support of Kernel Address Space Layout Randomization (KASLR), 2195 this randomizes the physical address at which the kernel image 2196 is decompressed and the virtual address where the kernel 2197 image is mapped, as a security feature that deters exploit 2198 attempts relying on knowledge of the location of kernel 2199 code internals. 2200 2201 On 64-bit, the kernel physical and virtual addresses are 2202 randomized separately. The physical address will be anywhere 2203 between 16MB and the top of physical memory (up to 64TB). The 2204 virtual address will be randomized from 16MB up to 1GB (9 bits 2205 of entropy). Note that this also reduces the memory space 2206 available to kernel modules from 1.5GB to 1GB. 2207 2208 On 32-bit, the kernel physical and virtual addresses are 2209 randomized together. They will be randomized from 16MB up to 2210 512MB (8 bits of entropy). 2211 2212 Entropy is generated using the RDRAND instruction if it is 2213 supported. If RDTSC is supported, its value is mixed into 2214 the entropy pool as well. If neither RDRAND nor RDTSC are 2215 supported, then entropy is read from the i8254 timer. The 2216 usable entropy is limited by the kernel being built using 2217 2GB addressing, and that PHYSICAL_ALIGN must be at a 2218 minimum of 2MB. As a result, only 10 bits of entropy are 2219 theoretically possible, but the implementations are further 2220 limited due to memory layouts. 2221 2222 If unsure, say Y. 2223 2224# Relocation on x86 needs some additional build support 2225config X86_NEED_RELOCS 2226 def_bool y 2227 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2228 2229config PHYSICAL_ALIGN 2230 hex "Alignment value to which kernel should be aligned" 2231 default "0x200000" 2232 range 0x2000 0x1000000 if X86_32 2233 range 0x200000 0x1000000 if X86_64 2234 ---help--- 2235 This value puts the alignment restrictions on physical address 2236 where kernel is loaded and run from. Kernel is compiled for an 2237 address which meets above alignment restriction. 2238 2239 If bootloader loads the kernel at a non-aligned address and 2240 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2241 address aligned to above value and run from there. 2242 2243 If bootloader loads the kernel at a non-aligned address and 2244 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2245 load address and decompress itself to the address it has been 2246 compiled for and run from there. The address for which kernel is 2247 compiled already meets above alignment restrictions. Hence the 2248 end result is that kernel runs from a physical address meeting 2249 above alignment restrictions. 2250 2251 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2252 this value must be a multiple of 0x200000. 2253 2254 Don't change this unless you know what you are doing. 2255 2256config DYNAMIC_MEMORY_LAYOUT 2257 bool 2258 ---help--- 2259 This option makes base addresses of vmalloc and vmemmap as well as 2260 __PAGE_OFFSET movable during boot. 2261 2262config RANDOMIZE_MEMORY 2263 bool "Randomize the kernel memory sections" 2264 depends on X86_64 2265 depends on RANDOMIZE_BASE 2266 select DYNAMIC_MEMORY_LAYOUT 2267 default RANDOMIZE_BASE 2268 ---help--- 2269 Randomizes the base virtual address of kernel memory sections 2270 (physical memory mapping, vmalloc & vmemmap). This security feature 2271 makes exploits relying on predictable memory locations less reliable. 2272 2273 The order of allocations remains unchanged. Entropy is generated in 2274 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2275 configuration have in average 30,000 different possible virtual 2276 addresses for each memory section. 2277 2278 If unsure, say Y. 2279 2280config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2281 hex "Physical memory mapping padding" if EXPERT 2282 depends on RANDOMIZE_MEMORY 2283 default "0xa" if MEMORY_HOTPLUG 2284 default "0x0" 2285 range 0x1 0x40 if MEMORY_HOTPLUG 2286 range 0x0 0x40 2287 ---help--- 2288 Define the padding in terabytes added to the existing physical 2289 memory size during kernel memory randomization. It is useful 2290 for memory hotplug support but reduces the entropy available for 2291 address randomization. 2292 2293 If unsure, leave at the default value. 2294 2295config HOTPLUG_CPU 2296 def_bool y 2297 depends on SMP 2298 2299config BOOTPARAM_HOTPLUG_CPU0 2300 bool "Set default setting of cpu0_hotpluggable" 2301 depends on HOTPLUG_CPU 2302 ---help--- 2303 Set whether default state of cpu0_hotpluggable is on or off. 2304 2305 Say Y here to enable CPU0 hotplug by default. If this switch 2306 is turned on, there is no need to give cpu0_hotplug kernel 2307 parameter and the CPU0 hotplug feature is enabled by default. 2308 2309 Please note: there are two known CPU0 dependencies if you want 2310 to enable the CPU0 hotplug feature either by this switch or by 2311 cpu0_hotplug kernel parameter. 2312 2313 First, resume from hibernate or suspend always starts from CPU0. 2314 So hibernate and suspend are prevented if CPU0 is offline. 2315 2316 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2317 offline if any interrupt can not migrate out of CPU0. There may 2318 be other CPU0 dependencies. 2319 2320 Please make sure the dependencies are under your control before 2321 you enable this feature. 2322 2323 Say N if you don't want to enable CPU0 hotplug feature by default. 2324 You still can enable the CPU0 hotplug feature at boot by kernel 2325 parameter cpu0_hotplug. 2326 2327config DEBUG_HOTPLUG_CPU0 2328 def_bool n 2329 prompt "Debug CPU0 hotplug" 2330 depends on HOTPLUG_CPU 2331 ---help--- 2332 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2333 soon as possible and boots up userspace with CPU0 offlined. User 2334 can online CPU0 back after boot time. 2335 2336 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2337 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2338 compilation or giving cpu0_hotplug kernel parameter at boot. 2339 2340 If unsure, say N. 2341 2342config COMPAT_VDSO 2343 def_bool n 2344 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2345 depends on COMPAT_32 2346 ---help--- 2347 Certain buggy versions of glibc will crash if they are 2348 presented with a 32-bit vDSO that is not mapped at the address 2349 indicated in its segment table. 2350 2351 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2352 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2353 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2354 the only released version with the bug, but OpenSUSE 9 2355 contains a buggy "glibc 2.3.2". 2356 2357 The symptom of the bug is that everything crashes on startup, saying: 2358 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2359 2360 Saying Y here changes the default value of the vdso32 boot 2361 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2362 This works around the glibc bug but hurts performance. 2363 2364 If unsure, say N: if you are compiling your own kernel, you 2365 are unlikely to be using a buggy version of glibc. 2366 2367choice 2368 prompt "vsyscall table for legacy applications" 2369 depends on X86_64 2370 default LEGACY_VSYSCALL_XONLY 2371 help 2372 Legacy user code that does not know how to find the vDSO expects 2373 to be able to issue three syscalls by calling fixed addresses in 2374 kernel space. Since this location is not randomized with ASLR, 2375 it can be used to assist security vulnerability exploitation. 2376 2377 This setting can be changed at boot time via the kernel command 2378 line parameter vsyscall=[emulate|xonly|none]. 2379 2380 On a system with recent enough glibc (2.14 or newer) and no 2381 static binaries, you can say None without a performance penalty 2382 to improve security. 2383 2384 If unsure, select "Emulate execution only". 2385 2386 config LEGACY_VSYSCALL_EMULATE 2387 bool "Full emulation" 2388 help 2389 The kernel traps and emulates calls into the fixed vsyscall 2390 address mapping. This makes the mapping non-executable, but 2391 it still contains readable known contents, which could be 2392 used in certain rare security vulnerability exploits. This 2393 configuration is recommended when using legacy userspace 2394 that still uses vsyscalls along with legacy binary 2395 instrumentation tools that require code to be readable. 2396 2397 An example of this type of legacy userspace is running 2398 Pin on an old binary that still uses vsyscalls. 2399 2400 config LEGACY_VSYSCALL_XONLY 2401 bool "Emulate execution only" 2402 help 2403 The kernel traps and emulates calls into the fixed vsyscall 2404 address mapping and does not allow reads. This 2405 configuration is recommended when userspace might use the 2406 legacy vsyscall area but support for legacy binary 2407 instrumentation of legacy code is not needed. It mitigates 2408 certain uses of the vsyscall area as an ASLR-bypassing 2409 buffer. 2410 2411 config LEGACY_VSYSCALL_NONE 2412 bool "None" 2413 help 2414 There will be no vsyscall mapping at all. This will 2415 eliminate any risk of ASLR bypass due to the vsyscall 2416 fixed address mapping. Attempts to use the vsyscalls 2417 will be reported to dmesg, so that either old or 2418 malicious userspace programs can be identified. 2419 2420endchoice 2421 2422config CMDLINE_BOOL 2423 bool "Built-in kernel command line" 2424 ---help--- 2425 Allow for specifying boot arguments to the kernel at 2426 build time. On some systems (e.g. embedded ones), it is 2427 necessary or convenient to provide some or all of the 2428 kernel boot arguments with the kernel itself (that is, 2429 to not rely on the boot loader to provide them.) 2430 2431 To compile command line arguments into the kernel, 2432 set this option to 'Y', then fill in the 2433 boot arguments in CONFIG_CMDLINE. 2434 2435 Systems with fully functional boot loaders (i.e. non-embedded) 2436 should leave this option set to 'N'. 2437 2438config CMDLINE 2439 string "Built-in kernel command string" 2440 depends on CMDLINE_BOOL 2441 default "" 2442 ---help--- 2443 Enter arguments here that should be compiled into the kernel 2444 image and used at boot time. If the boot loader provides a 2445 command line at boot time, it is appended to this string to 2446 form the full kernel command line, when the system boots. 2447 2448 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2449 change this behavior. 2450 2451 In most cases, the command line (whether built-in or provided 2452 by the boot loader) should specify the device for the root 2453 file system. 2454 2455config CMDLINE_OVERRIDE 2456 bool "Built-in command line overrides boot loader arguments" 2457 depends on CMDLINE_BOOL 2458 ---help--- 2459 Set this option to 'Y' to have the kernel ignore the boot loader 2460 command line, and use ONLY the built-in command line. 2461 2462 This is used to work around broken boot loaders. This should 2463 be set to 'N' under normal conditions. 2464 2465config MODIFY_LDT_SYSCALL 2466 bool "Enable the LDT (local descriptor table)" if EXPERT 2467 default y 2468 ---help--- 2469 Linux can allow user programs to install a per-process x86 2470 Local Descriptor Table (LDT) using the modify_ldt(2) system 2471 call. This is required to run 16-bit or segmented code such as 2472 DOSEMU or some Wine programs. It is also used by some very old 2473 threading libraries. 2474 2475 Enabling this feature adds a small amount of overhead to 2476 context switches and increases the low-level kernel attack 2477 surface. Disabling it removes the modify_ldt(2) system call. 2478 2479 Saying 'N' here may make sense for embedded or server kernels. 2480 2481source "kernel/livepatch/Kconfig" 2482 2483endmenu 2484 2485config ARCH_HAS_ADD_PAGES 2486 def_bool y 2487 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2488 2489config ARCH_ENABLE_MEMORY_HOTPLUG 2490 def_bool y 2491 depends on X86_64 || (X86_32 && HIGHMEM) 2492 2493config ARCH_ENABLE_MEMORY_HOTREMOVE 2494 def_bool y 2495 depends on MEMORY_HOTPLUG 2496 2497config USE_PERCPU_NUMA_NODE_ID 2498 def_bool y 2499 depends on NUMA 2500 2501config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2502 def_bool y 2503 depends on X86_64 || X86_PAE 2504 2505config ARCH_ENABLE_HUGEPAGE_MIGRATION 2506 def_bool y 2507 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2508 2509config ARCH_ENABLE_THP_MIGRATION 2510 def_bool y 2511 depends on X86_64 && TRANSPARENT_HUGEPAGE 2512 2513menu "Power management and ACPI options" 2514 2515config ARCH_HIBERNATION_HEADER 2516 def_bool y 2517 depends on HIBERNATION 2518 2519source "kernel/power/Kconfig" 2520 2521source "drivers/acpi/Kconfig" 2522 2523source "drivers/sfi/Kconfig" 2524 2525config X86_APM_BOOT 2526 def_bool y 2527 depends on APM 2528 2529menuconfig APM 2530 tristate "APM (Advanced Power Management) BIOS support" 2531 depends on X86_32 && PM_SLEEP 2532 ---help--- 2533 APM is a BIOS specification for saving power using several different 2534 techniques. This is mostly useful for battery powered laptops with 2535 APM compliant BIOSes. If you say Y here, the system time will be 2536 reset after a RESUME operation, the /proc/apm device will provide 2537 battery status information, and user-space programs will receive 2538 notification of APM "events" (e.g. battery status change). 2539 2540 If you select "Y" here, you can disable actual use of the APM 2541 BIOS by passing the "apm=off" option to the kernel at boot time. 2542 2543 Note that the APM support is almost completely disabled for 2544 machines with more than one CPU. 2545 2546 In order to use APM, you will need supporting software. For location 2547 and more information, read <file:Documentation/power/apm-acpi.rst> 2548 and the Battery Powered Linux mini-HOWTO, available from 2549 <http://www.tldp.org/docs.html#howto>. 2550 2551 This driver does not spin down disk drives (see the hdparm(8) 2552 manpage ("man 8 hdparm") for that), and it doesn't turn off 2553 VESA-compliant "green" monitors. 2554 2555 This driver does not support the TI 4000M TravelMate and the ACER 2556 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2557 desktop machines also don't have compliant BIOSes, and this driver 2558 may cause those machines to panic during the boot phase. 2559 2560 Generally, if you don't have a battery in your machine, there isn't 2561 much point in using this driver and you should say N. If you get 2562 random kernel OOPSes or reboots that don't seem to be related to 2563 anything, try disabling/enabling this option (or disabling/enabling 2564 APM in your BIOS). 2565 2566 Some other things you should try when experiencing seemingly random, 2567 "weird" problems: 2568 2569 1) make sure that you have enough swap space and that it is 2570 enabled. 2571 2) pass the "no-hlt" option to the kernel 2572 3) switch on floating point emulation in the kernel and pass 2573 the "no387" option to the kernel 2574 4) pass the "floppy=nodma" option to the kernel 2575 5) pass the "mem=4M" option to the kernel (thereby disabling 2576 all but the first 4 MB of RAM) 2577 6) make sure that the CPU is not over clocked. 2578 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2579 8) disable the cache from your BIOS settings 2580 9) install a fan for the video card or exchange video RAM 2581 10) install a better fan for the CPU 2582 11) exchange RAM chips 2583 12) exchange the motherboard. 2584 2585 To compile this driver as a module, choose M here: the 2586 module will be called apm. 2587 2588if APM 2589 2590config APM_IGNORE_USER_SUSPEND 2591 bool "Ignore USER SUSPEND" 2592 ---help--- 2593 This option will ignore USER SUSPEND requests. On machines with a 2594 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2595 series notebooks, it is necessary to say Y because of a BIOS bug. 2596 2597config APM_DO_ENABLE 2598 bool "Enable PM at boot time" 2599 ---help--- 2600 Enable APM features at boot time. From page 36 of the APM BIOS 2601 specification: "When disabled, the APM BIOS does not automatically 2602 power manage devices, enter the Standby State, enter the Suspend 2603 State, or take power saving steps in response to CPU Idle calls." 2604 This driver will make CPU Idle calls when Linux is idle (unless this 2605 feature is turned off -- see "Do CPU IDLE calls", below). This 2606 should always save battery power, but more complicated APM features 2607 will be dependent on your BIOS implementation. You may need to turn 2608 this option off if your computer hangs at boot time when using APM 2609 support, or if it beeps continuously instead of suspending. Turn 2610 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2611 T400CDT. This is off by default since most machines do fine without 2612 this feature. 2613 2614config APM_CPU_IDLE 2615 depends on CPU_IDLE 2616 bool "Make CPU Idle calls when idle" 2617 ---help--- 2618 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2619 On some machines, this can activate improved power savings, such as 2620 a slowed CPU clock rate, when the machine is idle. These idle calls 2621 are made after the idle loop has run for some length of time (e.g., 2622 333 mS). On some machines, this will cause a hang at boot time or 2623 whenever the CPU becomes idle. (On machines with more than one CPU, 2624 this option does nothing.) 2625 2626config APM_DISPLAY_BLANK 2627 bool "Enable console blanking using APM" 2628 ---help--- 2629 Enable console blanking using the APM. Some laptops can use this to 2630 turn off the LCD backlight when the screen blanker of the Linux 2631 virtual console blanks the screen. Note that this is only used by 2632 the virtual console screen blanker, and won't turn off the backlight 2633 when using the X Window system. This also doesn't have anything to 2634 do with your VESA-compliant power-saving monitor. Further, this 2635 option doesn't work for all laptops -- it might not turn off your 2636 backlight at all, or it might print a lot of errors to the console, 2637 especially if you are using gpm. 2638 2639config APM_ALLOW_INTS 2640 bool "Allow interrupts during APM BIOS calls" 2641 ---help--- 2642 Normally we disable external interrupts while we are making calls to 2643 the APM BIOS as a measure to lessen the effects of a badly behaving 2644 BIOS implementation. The BIOS should reenable interrupts if it 2645 needs to. Unfortunately, some BIOSes do not -- especially those in 2646 many of the newer IBM Thinkpads. If you experience hangs when you 2647 suspend, try setting this to Y. Otherwise, say N. 2648 2649endif # APM 2650 2651source "drivers/cpufreq/Kconfig" 2652 2653source "drivers/cpuidle/Kconfig" 2654 2655source "drivers/idle/Kconfig" 2656 2657endmenu 2658 2659 2660menu "Bus options (PCI etc.)" 2661 2662choice 2663 prompt "PCI access mode" 2664 depends on X86_32 && PCI 2665 default PCI_GOANY 2666 ---help--- 2667 On PCI systems, the BIOS can be used to detect the PCI devices and 2668 determine their configuration. However, some old PCI motherboards 2669 have BIOS bugs and may crash if this is done. Also, some embedded 2670 PCI-based systems don't have any BIOS at all. Linux can also try to 2671 detect the PCI hardware directly without using the BIOS. 2672 2673 With this option, you can specify how Linux should detect the 2674 PCI devices. If you choose "BIOS", the BIOS will be used, 2675 if you choose "Direct", the BIOS won't be used, and if you 2676 choose "MMConfig", then PCI Express MMCONFIG will be used. 2677 If you choose "Any", the kernel will try MMCONFIG, then the 2678 direct access method and falls back to the BIOS if that doesn't 2679 work. If unsure, go with the default, which is "Any". 2680 2681config PCI_GOBIOS 2682 bool "BIOS" 2683 2684config PCI_GOMMCONFIG 2685 bool "MMConfig" 2686 2687config PCI_GODIRECT 2688 bool "Direct" 2689 2690config PCI_GOOLPC 2691 bool "OLPC XO-1" 2692 depends on OLPC 2693 2694config PCI_GOANY 2695 bool "Any" 2696 2697endchoice 2698 2699config PCI_BIOS 2700 def_bool y 2701 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2702 2703# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2704config PCI_DIRECT 2705 def_bool y 2706 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2707 2708config PCI_MMCONFIG 2709 bool "Support mmconfig PCI config space access" if X86_64 2710 default y 2711 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2712 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2713 2714config PCI_OLPC 2715 def_bool y 2716 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2717 2718config PCI_XEN 2719 def_bool y 2720 depends on PCI && XEN 2721 select SWIOTLB_XEN 2722 2723config MMCONF_FAM10H 2724 def_bool y 2725 depends on X86_64 && PCI_MMCONFIG && ACPI 2726 2727config PCI_CNB20LE_QUIRK 2728 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2729 depends on PCI 2730 help 2731 Read the PCI windows out of the CNB20LE host bridge. This allows 2732 PCI hotplug to work on systems with the CNB20LE chipset which do 2733 not have ACPI. 2734 2735 There's no public spec for this chipset, and this functionality 2736 is known to be incomplete. 2737 2738 You should say N unless you know you need this. 2739 2740config ISA_BUS 2741 bool "ISA bus support on modern systems" if EXPERT 2742 help 2743 Expose ISA bus device drivers and options available for selection and 2744 configuration. Enable this option if your target machine has an ISA 2745 bus. ISA is an older system, displaced by PCI and newer bus 2746 architectures -- if your target machine is modern, it probably does 2747 not have an ISA bus. 2748 2749 If unsure, say N. 2750 2751# x86_64 have no ISA slots, but can have ISA-style DMA. 2752config ISA_DMA_API 2753 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2754 default y 2755 help 2756 Enables ISA-style DMA support for devices requiring such controllers. 2757 If unsure, say Y. 2758 2759if X86_32 2760 2761config ISA 2762 bool "ISA support" 2763 ---help--- 2764 Find out whether you have ISA slots on your motherboard. ISA is the 2765 name of a bus system, i.e. the way the CPU talks to the other stuff 2766 inside your box. Other bus systems are PCI, EISA, MicroChannel 2767 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2768 newer boards don't support it. If you have ISA, say Y, otherwise N. 2769 2770config SCx200 2771 tristate "NatSemi SCx200 support" 2772 ---help--- 2773 This provides basic support for National Semiconductor's 2774 (now AMD's) Geode processors. The driver probes for the 2775 PCI-IDs of several on-chip devices, so its a good dependency 2776 for other scx200_* drivers. 2777 2778 If compiled as a module, the driver is named scx200. 2779 2780config SCx200HR_TIMER 2781 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2782 depends on SCx200 2783 default y 2784 ---help--- 2785 This driver provides a clocksource built upon the on-chip 2786 27MHz high-resolution timer. Its also a workaround for 2787 NSC Geode SC-1100's buggy TSC, which loses time when the 2788 processor goes idle (as is done by the scheduler). The 2789 other workaround is idle=poll boot option. 2790 2791config OLPC 2792 bool "One Laptop Per Child support" 2793 depends on !X86_PAE 2794 select GPIOLIB 2795 select OF 2796 select OF_PROMTREE 2797 select IRQ_DOMAIN 2798 select OLPC_EC 2799 ---help--- 2800 Add support for detecting the unique features of the OLPC 2801 XO hardware. 2802 2803config OLPC_XO1_PM 2804 bool "OLPC XO-1 Power Management" 2805 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2806 ---help--- 2807 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2808 2809config OLPC_XO1_RTC 2810 bool "OLPC XO-1 Real Time Clock" 2811 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2812 ---help--- 2813 Add support for the XO-1 real time clock, which can be used as a 2814 programmable wakeup source. 2815 2816config OLPC_XO1_SCI 2817 bool "OLPC XO-1 SCI extras" 2818 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2819 depends on INPUT=y 2820 select POWER_SUPPLY 2821 ---help--- 2822 Add support for SCI-based features of the OLPC XO-1 laptop: 2823 - EC-driven system wakeups 2824 - Power button 2825 - Ebook switch 2826 - Lid switch 2827 - AC adapter status updates 2828 - Battery status updates 2829 2830config OLPC_XO15_SCI 2831 bool "OLPC XO-1.5 SCI extras" 2832 depends on OLPC && ACPI 2833 select POWER_SUPPLY 2834 ---help--- 2835 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2836 - EC-driven system wakeups 2837 - AC adapter status updates 2838 - Battery status updates 2839 2840config ALIX 2841 bool "PCEngines ALIX System Support (LED setup)" 2842 select GPIOLIB 2843 ---help--- 2844 This option enables system support for the PCEngines ALIX. 2845 At present this just sets up LEDs for GPIO control on 2846 ALIX2/3/6 boards. However, other system specific setup should 2847 get added here. 2848 2849 Note: You must still enable the drivers for GPIO and LED support 2850 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2851 2852 Note: You have to set alix.force=1 for boards with Award BIOS. 2853 2854config NET5501 2855 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2856 select GPIOLIB 2857 ---help--- 2858 This option enables system support for the Soekris Engineering net5501. 2859 2860config GEOS 2861 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2862 select GPIOLIB 2863 depends on DMI 2864 ---help--- 2865 This option enables system support for the Traverse Technologies GEOS. 2866 2867config TS5500 2868 bool "Technologic Systems TS-5500 platform support" 2869 depends on MELAN 2870 select CHECK_SIGNATURE 2871 select NEW_LEDS 2872 select LEDS_CLASS 2873 ---help--- 2874 This option enables system support for the Technologic Systems TS-5500. 2875 2876endif # X86_32 2877 2878config AMD_NB 2879 def_bool y 2880 depends on CPU_SUP_AMD && PCI 2881 2882config X86_SYSFB 2883 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2884 help 2885 Firmwares often provide initial graphics framebuffers so the BIOS, 2886 bootloader or kernel can show basic video-output during boot for 2887 user-guidance and debugging. Historically, x86 used the VESA BIOS 2888 Extensions and EFI-framebuffers for this, which are mostly limited 2889 to x86. 2890 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2891 framebuffers so the new generic system-framebuffer drivers can be 2892 used on x86. If the framebuffer is not compatible with the generic 2893 modes, it is advertised as fallback platform framebuffer so legacy 2894 drivers like efifb, vesafb and uvesafb can pick it up. 2895 If this option is not selected, all system framebuffers are always 2896 marked as fallback platform framebuffers as usual. 2897 2898 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2899 not be able to pick up generic system framebuffers if this option 2900 is selected. You are highly encouraged to enable simplefb as 2901 replacement if you select this option. simplefb can correctly deal 2902 with generic system framebuffers. But you should still keep vesafb 2903 and others enabled as fallback if a system framebuffer is 2904 incompatible with simplefb. 2905 2906 If unsure, say Y. 2907 2908endmenu 2909 2910 2911menu "Binary Emulations" 2912 2913config IA32_EMULATION 2914 bool "IA32 Emulation" 2915 depends on X86_64 2916 select ARCH_WANT_OLD_COMPAT_IPC 2917 select BINFMT_ELF 2918 select COMPAT_BINFMT_ELF 2919 select COMPAT_OLD_SIGACTION 2920 ---help--- 2921 Include code to run legacy 32-bit programs under a 2922 64-bit kernel. You should likely turn this on, unless you're 2923 100% sure that you don't have any 32-bit programs left. 2924 2925config IA32_AOUT 2926 tristate "IA32 a.out support" 2927 depends on IA32_EMULATION 2928 depends on BROKEN 2929 ---help--- 2930 Support old a.out binaries in the 32bit emulation. 2931 2932config X86_X32 2933 bool "x32 ABI for 64-bit mode" 2934 depends on X86_64 2935 ---help--- 2936 Include code to run binaries for the x32 native 32-bit ABI 2937 for 64-bit processors. An x32 process gets access to the 2938 full 64-bit register file and wide data path while leaving 2939 pointers at 32 bits for smaller memory footprint. 2940 2941 You will need a recent binutils (2.22 or later) with 2942 elf32_x86_64 support enabled to compile a kernel with this 2943 option set. 2944 2945config COMPAT_32 2946 def_bool y 2947 depends on IA32_EMULATION || X86_32 2948 select HAVE_UID16 2949 select OLD_SIGSUSPEND3 2950 2951config COMPAT 2952 def_bool y 2953 depends on IA32_EMULATION || X86_X32 2954 2955if COMPAT 2956config COMPAT_FOR_U64_ALIGNMENT 2957 def_bool y 2958 2959config SYSVIPC_COMPAT 2960 def_bool y 2961 depends on SYSVIPC 2962endif 2963 2964endmenu 2965 2966 2967config HAVE_ATOMIC_IOMAP 2968 def_bool y 2969 depends on X86_32 2970 2971config X86_DEV_DMA_OPS 2972 bool 2973 2974source "drivers/firmware/Kconfig" 2975 2976source "arch/x86/kvm/Kconfig" 2977