1# SPDX-License-Identifier: GPL-2.0 2# Select 32 or 64 bit 3config 64BIT 4 bool "64-bit kernel" if "$(ARCH)" = "x86" 5 default "$(ARCH)" != "i386" 6 ---help--- 7 Say yes to build a 64-bit kernel - formerly known as x86_64 8 Say no to build a 32-bit kernel - formerly known as i386 9 10config X86_32 11 def_bool y 12 depends on !64BIT 13 # Options that are inherently 32-bit kernel only: 14 select ARCH_WANT_IPC_PARSE_VERSION 15 select CLKSRC_I8253 16 select CLONE_BACKWARDS 17 select HAVE_DEBUG_STACKOVERFLOW 18 select MODULES_USE_ELF_REL 19 select OLD_SIGACTION 20 select GENERIC_VDSO_32 21 22config X86_64 23 def_bool y 24 depends on 64BIT 25 # Options that are inherently 64-bit kernel only: 26 select ARCH_HAS_GIGANTIC_PAGE 27 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 28 select ARCH_USE_CMPXCHG_LOCKREF 29 select HAVE_ARCH_SOFT_DIRTY 30 select MODULES_USE_ELF_RELA 31 select NEED_DMA_MAP_STATE 32 select SWIOTLB 33 select ARCH_HAS_SYSCALL_WRAPPER 34 35config FORCE_DYNAMIC_FTRACE 36 def_bool y 37 depends on X86_32 38 depends on FUNCTION_TRACER 39 select DYNAMIC_FTRACE 40 help 41 We keep the static function tracing (!DYNAMIC_FTRACE) around 42 in order to test the non static function tracing in the 43 generic code, as other architectures still use it. But we 44 only need to keep it around for x86_64. No need to keep it 45 for x86_32. For x86_32, force DYNAMIC_FTRACE. 46# 47# Arch settings 48# 49# ( Note that options that are marked 'if X86_64' could in principle be 50# ported to 32-bit as well. ) 51# 52config X86 53 def_bool y 54 # 55 # Note: keep this list sorted alphabetically 56 # 57 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 58 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 59 select ARCH_32BIT_OFF_T if X86_32 60 select ARCH_CLOCKSOURCE_DATA 61 select ARCH_CLOCKSOURCE_INIT 62 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 63 select ARCH_HAS_DEBUG_VIRTUAL 64 select ARCH_HAS_DEVMEM_IS_ALLOWED 65 select ARCH_HAS_ELF_RANDOMIZE 66 select ARCH_HAS_FAST_MULTIPLIER 67 select ARCH_HAS_FILTER_PGPROT 68 select ARCH_HAS_FORTIFY_SOURCE 69 select ARCH_HAS_GCOV_PROFILE_ALL 70 select ARCH_HAS_KCOV if X86_64 71 select ARCH_HAS_MEM_ENCRYPT 72 select ARCH_HAS_MEMBARRIER_SYNC_CORE 73 select ARCH_HAS_PMEM_API if X86_64 74 select ARCH_HAS_PTE_DEVMAP if X86_64 75 select ARCH_HAS_PTE_SPECIAL 76 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 77 select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE 78 select ARCH_HAS_SET_MEMORY 79 select ARCH_HAS_SET_DIRECT_MAP 80 select ARCH_HAS_STRICT_KERNEL_RWX 81 select ARCH_HAS_STRICT_MODULE_RWX 82 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 83 select ARCH_HAS_UBSAN_SANITIZE_ALL 84 select ARCH_HAVE_NMI_SAFE_CMPXCHG 85 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 86 select ARCH_MIGHT_HAVE_PC_PARPORT 87 select ARCH_MIGHT_HAVE_PC_SERIO 88 select ARCH_STACKWALK 89 select ARCH_SUPPORTS_ACPI 90 select ARCH_SUPPORTS_ATOMIC_RMW 91 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 92 select ARCH_USE_BUILTIN_BSWAP 93 select ARCH_USE_QUEUED_RWLOCKS 94 select ARCH_USE_QUEUED_SPINLOCKS 95 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 96 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 97 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 98 select ARCH_WANT_HUGE_PMD_SHARE 99 select ARCH_WANTS_THP_SWAP if X86_64 100 select BUILDTIME_TABLE_SORT 101 select CLKEVT_I8253 102 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 103 select CLOCKSOURCE_WATCHDOG 104 select DCACHE_WORD_ACCESS 105 select EDAC_ATOMIC_SCRUB 106 select EDAC_SUPPORT 107 select GENERIC_CLOCKEVENTS 108 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 109 select GENERIC_CLOCKEVENTS_MIN_ADJUST 110 select GENERIC_CMOS_UPDATE 111 select GENERIC_CPU_AUTOPROBE 112 select GENERIC_CPU_VULNERABILITIES 113 select GENERIC_EARLY_IOREMAP 114 select GENERIC_FIND_FIRST_BIT 115 select GENERIC_IOMAP 116 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 117 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 118 select GENERIC_IRQ_MIGRATION if SMP 119 select GENERIC_IRQ_PROBE 120 select GENERIC_IRQ_RESERVATION_MODE 121 select GENERIC_IRQ_SHOW 122 select GENERIC_PENDING_IRQ if SMP 123 select GENERIC_PTDUMP 124 select GENERIC_SMP_IDLE_THREAD 125 select GENERIC_STRNCPY_FROM_USER 126 select GENERIC_STRNLEN_USER 127 select GENERIC_TIME_VSYSCALL 128 select GENERIC_GETTIMEOFDAY 129 select GENERIC_VDSO_TIME_NS 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_KASAN_VMALLOC if X86_64 141 select HAVE_ARCH_KGDB 142 select HAVE_ARCH_MMAP_RND_BITS if MMU 143 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 144 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 145 select HAVE_ARCH_PREL32_RELOCATIONS 146 select HAVE_ARCH_SECCOMP_FILTER 147 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 148 select HAVE_ARCH_STACKLEAK 149 select HAVE_ARCH_TRACEHOOK 150 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 151 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 152 select HAVE_ARCH_VMAP_STACK if X86_64 153 select HAVE_ARCH_WITHIN_STACK_FRAMES 154 select HAVE_ASM_MODVERSIONS 155 select HAVE_CMPXCHG_DOUBLE 156 select HAVE_CMPXCHG_LOCAL 157 select HAVE_CONTEXT_TRACKING if X86_64 158 select HAVE_COPY_THREAD_TLS 159 select HAVE_C_RECORDMCOUNT 160 select HAVE_DEBUG_KMEMLEAK 161 select HAVE_DMA_CONTIGUOUS 162 select HAVE_DYNAMIC_FTRACE 163 select HAVE_DYNAMIC_FTRACE_WITH_REGS 164 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 165 select HAVE_EBPF_JIT 166 select HAVE_EFFICIENT_UNALIGNED_ACCESS 167 select HAVE_EISA 168 select HAVE_EXIT_THREAD 169 select HAVE_FAST_GUP 170 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 171 select HAVE_FTRACE_MCOUNT_RECORD 172 select HAVE_FUNCTION_GRAPH_TRACER 173 select HAVE_FUNCTION_TRACER 174 select HAVE_GCC_PLUGINS 175 select HAVE_HW_BREAKPOINT 176 select HAVE_IDE 177 select HAVE_IOREMAP_PROT 178 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 179 select HAVE_IRQ_TIME_ACCOUNTING 180 select HAVE_KERNEL_BZIP2 181 select HAVE_KERNEL_GZIP 182 select HAVE_KERNEL_LZ4 183 select HAVE_KERNEL_LZMA 184 select HAVE_KERNEL_LZO 185 select HAVE_KERNEL_XZ 186 select HAVE_KPROBES 187 select HAVE_KPROBES_ON_FTRACE 188 select HAVE_FUNCTION_ERROR_INJECTION 189 select HAVE_KRETPROBES 190 select HAVE_KVM 191 select HAVE_LIVEPATCH if X86_64 192 select HAVE_MEMBLOCK_NODE_MAP 193 select HAVE_MIXED_BREAKPOINTS_REGS 194 select HAVE_MOD_ARCH_SPECIFIC 195 select HAVE_MOVE_PMD 196 select HAVE_NMI 197 select HAVE_OPROFILE 198 select HAVE_OPTPROBES 199 select HAVE_PCSPKR_PLATFORM 200 select HAVE_PERF_EVENTS 201 select HAVE_PERF_EVENTS_NMI 202 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 203 select HAVE_PCI 204 select HAVE_PERF_REGS 205 select HAVE_PERF_USER_STACK_DUMP 206 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 207 select HAVE_REGS_AND_STACK_ACCESS_API 208 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 209 select HAVE_FUNCTION_ARG_ACCESS_API 210 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 211 select HAVE_STACK_VALIDATION if X86_64 212 select HAVE_RSEQ 213 select HAVE_SYSCALL_TRACEPOINTS 214 select HAVE_UNSTABLE_SCHED_CLOCK 215 select HAVE_USER_RETURN_NOTIFIER 216 select HAVE_GENERIC_VDSO 217 select HOTPLUG_SMT if SMP 218 select IRQ_FORCED_THREADING 219 select NEED_SG_DMA_LENGTH 220 select PCI_DOMAINS if PCI 221 select PCI_LOCKLESS_CONFIG if PCI 222 select PERF_EVENTS 223 select RTC_LIB 224 select RTC_MC146818_LIB 225 select SPARSE_IRQ 226 select SRCU 227 select SYSCTL_EXCEPTION_TRACE 228 select THREAD_INFO_IN_TASK 229 select USER_STACKTRACE_SUPPORT 230 select VIRT_TO_BUS 231 select X86_FEATURE_NAMES if PROC_FS 232 select PROC_PID_ARCH_STATUS if PROC_FS 233 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 234 235config INSTRUCTION_DECODER 236 def_bool y 237 depends on KPROBES || PERF_EVENTS || UPROBES 238 239config OUTPUT_FORMAT 240 string 241 default "elf32-i386" if X86_32 242 default "elf64-x86-64" if X86_64 243 244config ARCH_DEFCONFIG 245 string 246 default "arch/x86/configs/i386_defconfig" if X86_32 247 default "arch/x86/configs/x86_64_defconfig" if X86_64 248 249config LOCKDEP_SUPPORT 250 def_bool y 251 252config STACKTRACE_SUPPORT 253 def_bool y 254 255config MMU 256 def_bool y 257 258config ARCH_MMAP_RND_BITS_MIN 259 default 28 if 64BIT 260 default 8 261 262config ARCH_MMAP_RND_BITS_MAX 263 default 32 if 64BIT 264 default 16 265 266config ARCH_MMAP_RND_COMPAT_BITS_MIN 267 default 8 268 269config ARCH_MMAP_RND_COMPAT_BITS_MAX 270 default 16 271 272config SBUS 273 bool 274 275config GENERIC_ISA_DMA 276 def_bool y 277 depends on ISA_DMA_API 278 279config GENERIC_BUG 280 def_bool y 281 depends on BUG 282 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 283 284config GENERIC_BUG_RELATIVE_POINTERS 285 bool 286 287config ARCH_MAY_HAVE_PC_FDC 288 def_bool y 289 depends on ISA_DMA_API 290 291config GENERIC_CALIBRATE_DELAY 292 def_bool y 293 294config ARCH_HAS_CPU_RELAX 295 def_bool y 296 297config ARCH_HAS_CACHE_LINE_SIZE 298 def_bool y 299 300config ARCH_HAS_FILTER_PGPROT 301 def_bool y 302 303config HAVE_SETUP_PER_CPU_AREA 304 def_bool y 305 306config NEED_PER_CPU_EMBED_FIRST_CHUNK 307 def_bool y 308 309config NEED_PER_CPU_PAGE_FIRST_CHUNK 310 def_bool y 311 312config ARCH_HIBERNATION_POSSIBLE 313 def_bool y 314 315config ARCH_SUSPEND_POSSIBLE 316 def_bool y 317 318config ARCH_WANT_GENERAL_HUGETLB 319 def_bool y 320 321config ZONE_DMA32 322 def_bool y if X86_64 323 324config AUDIT_ARCH 325 def_bool y if X86_64 326 327config ARCH_SUPPORTS_DEBUG_PAGEALLOC 328 def_bool y 329 330config KASAN_SHADOW_OFFSET 331 hex 332 depends on KASAN 333 default 0xdffffc0000000000 334 335config HAVE_INTEL_TXT 336 def_bool y 337 depends on INTEL_IOMMU && ACPI 338 339config X86_32_SMP 340 def_bool y 341 depends on X86_32 && SMP 342 343config X86_64_SMP 344 def_bool y 345 depends on X86_64 && SMP 346 347config X86_32_LAZY_GS 348 def_bool y 349 depends on X86_32 && !STACKPROTECTOR 350 351config ARCH_SUPPORTS_UPROBES 352 def_bool y 353 354config FIX_EARLYCON_MEM 355 def_bool y 356 357config DYNAMIC_PHYSICAL_MASK 358 bool 359 360config PGTABLE_LEVELS 361 int 362 default 5 if X86_5LEVEL 363 default 4 if X86_64 364 default 3 if X86_PAE 365 default 2 366 367config CC_HAS_SANE_STACKPROTECTOR 368 bool 369 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 370 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 371 help 372 We have to make sure stack protector is unconditionally disabled if 373 the compiler produces broken code. 374 375menu "Processor type and features" 376 377config ZONE_DMA 378 bool "DMA memory allocation support" if EXPERT 379 default y 380 help 381 DMA memory allocation support allows devices with less than 32-bit 382 addressing to allocate within the first 16MB of address space. 383 Disable if no such devices will be used. 384 385 If unsure, say Y. 386 387config SMP 388 bool "Symmetric multi-processing support" 389 ---help--- 390 This enables support for systems with more than one CPU. If you have 391 a system with only one CPU, say N. If you have a system with more 392 than one CPU, say Y. 393 394 If you say N here, the kernel will run on uni- and multiprocessor 395 machines, but will use only one CPU of a multiprocessor machine. If 396 you say Y here, the kernel will run on many, but not all, 397 uniprocessor machines. On a uniprocessor machine, the kernel 398 will run faster if you say N here. 399 400 Note that if you say Y here and choose architecture "586" or 401 "Pentium" under "Processor family", the kernel will not work on 486 402 architectures. Similarly, multiprocessor kernels for the "PPro" 403 architecture may not work on all Pentium based boards. 404 405 People using multiprocessor machines who say Y here should also say 406 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 407 Management" code will be disabled if you say Y here. 408 409 See also <file:Documentation/x86/i386/IO-APIC.rst>, 410 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 411 <http://www.tldp.org/docs.html#howto>. 412 413 If you don't know what to do here, say N. 414 415config X86_FEATURE_NAMES 416 bool "Processor feature human-readable names" if EMBEDDED 417 default y 418 ---help--- 419 This option compiles in a table of x86 feature bits and corresponding 420 names. This is required to support /proc/cpuinfo and a few kernel 421 messages. You can disable this to save space, at the expense of 422 making those few kernel messages show numeric feature bits instead. 423 424 If in doubt, say Y. 425 426config X86_X2APIC 427 bool "Support x2apic" 428 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 429 ---help--- 430 This enables x2apic support on CPUs that have this feature. 431 432 This allows 32-bit apic IDs (so it can support very large systems), 433 and accesses the local apic via MSRs not via mmio. 434 435 If you don't know what to do here, say N. 436 437config X86_MPPARSE 438 bool "Enable MPS table" if ACPI || SFI 439 default y 440 depends on X86_LOCAL_APIC 441 ---help--- 442 For old smp systems that do not have proper acpi support. Newer systems 443 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 444 445config GOLDFISH 446 def_bool y 447 depends on X86_GOLDFISH 448 449config RETPOLINE 450 bool "Avoid speculative indirect branches in kernel" 451 default y 452 select STACK_VALIDATION if HAVE_STACK_VALIDATION 453 help 454 Compile kernel with the retpoline compiler options to guard against 455 kernel-to-user data leaks by avoiding speculative indirect 456 branches. Requires a compiler with -mindirect-branch=thunk-extern 457 support for full protection. The kernel may run slower. 458 459config X86_CPU_RESCTRL 460 bool "x86 CPU resource control support" 461 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 462 select KERNFS 463 select PROC_CPU_RESCTRL if PROC_FS 464 help 465 Enable x86 CPU resource control support. 466 467 Provide support for the allocation and monitoring of system resources 468 usage by the CPU. 469 470 Intel calls this Intel Resource Director Technology 471 (Intel(R) RDT). More information about RDT can be found in the 472 Intel x86 Architecture Software Developer Manual. 473 474 AMD calls this AMD Platform Quality of Service (AMD QoS). 475 More information about AMD QoS can be found in the AMD64 Technology 476 Platform Quality of Service Extensions manual. 477 478 Say N if unsure. 479 480if X86_32 481config X86_BIGSMP 482 bool "Support for big SMP systems with more than 8 CPUs" 483 depends on SMP 484 ---help--- 485 This option is needed for the systems that have more than 8 CPUs. 486 487config X86_EXTENDED_PLATFORM 488 bool "Support for extended (non-PC) x86 platforms" 489 default y 490 ---help--- 491 If you disable this option then the kernel will only support 492 standard PC platforms. (which covers the vast majority of 493 systems out there.) 494 495 If you enable this option then you'll be able to select support 496 for the following (non-PC) 32 bit x86 platforms: 497 Goldfish (Android emulator) 498 AMD Elan 499 RDC R-321x SoC 500 SGI 320/540 (Visual Workstation) 501 STA2X11-based (e.g. Northville) 502 Moorestown MID devices 503 504 If you have one of these systems, or if you want to build a 505 generic distribution kernel, say Y here - otherwise say N. 506endif 507 508if X86_64 509config X86_EXTENDED_PLATFORM 510 bool "Support for extended (non-PC) x86 platforms" 511 default y 512 ---help--- 513 If you disable this option then the kernel will only support 514 standard PC platforms. (which covers the vast majority of 515 systems out there.) 516 517 If you enable this option then you'll be able to select support 518 for the following (non-PC) 64 bit x86 platforms: 519 Numascale NumaChip 520 ScaleMP vSMP 521 SGI Ultraviolet 522 523 If you have one of these systems, or if you want to build a 524 generic distribution kernel, say Y here - otherwise say N. 525endif 526# This is an alphabetically sorted list of 64 bit extended platforms 527# Please maintain the alphabetic order if and when there are additions 528config X86_NUMACHIP 529 bool "Numascale NumaChip" 530 depends on X86_64 531 depends on X86_EXTENDED_PLATFORM 532 depends on NUMA 533 depends on SMP 534 depends on X86_X2APIC 535 depends on PCI_MMCONFIG 536 ---help--- 537 Adds support for Numascale NumaChip large-SMP systems. Needed to 538 enable more than ~168 cores. 539 If you don't have one of these, you should say N here. 540 541config X86_VSMP 542 bool "ScaleMP vSMP" 543 select HYPERVISOR_GUEST 544 select PARAVIRT 545 depends on X86_64 && PCI 546 depends on X86_EXTENDED_PLATFORM 547 depends on SMP 548 ---help--- 549 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 550 supposed to run on these EM64T-based machines. Only choose this option 551 if you have one of these machines. 552 553config X86_UV 554 bool "SGI Ultraviolet" 555 depends on X86_64 556 depends on X86_EXTENDED_PLATFORM 557 depends on NUMA 558 depends on EFI 559 depends on X86_X2APIC 560 depends on PCI 561 ---help--- 562 This option is needed in order to support SGI Ultraviolet systems. 563 If you don't have one of these, you should say N here. 564 565# Following is an alphabetically sorted list of 32 bit extended platforms 566# Please maintain the alphabetic order if and when there are additions 567 568config X86_GOLDFISH 569 bool "Goldfish (Virtual Platform)" 570 depends on X86_EXTENDED_PLATFORM 571 ---help--- 572 Enable support for the Goldfish virtual platform used primarily 573 for Android development. Unless you are building for the Android 574 Goldfish emulator say N here. 575 576config X86_INTEL_CE 577 bool "CE4100 TV platform" 578 depends on PCI 579 depends on PCI_GODIRECT 580 depends on X86_IO_APIC 581 depends on X86_32 582 depends on X86_EXTENDED_PLATFORM 583 select X86_REBOOTFIXUPS 584 select OF 585 select OF_EARLY_FLATTREE 586 ---help--- 587 Select for the Intel CE media processor (CE4100) SOC. 588 This option compiles in support for the CE4100 SOC for settop 589 boxes and media devices. 590 591config X86_INTEL_MID 592 bool "Intel MID platform support" 593 depends on X86_EXTENDED_PLATFORM 594 depends on X86_PLATFORM_DEVICES 595 depends on PCI 596 depends on X86_64 || (PCI_GOANY && X86_32) 597 depends on X86_IO_APIC 598 select SFI 599 select I2C 600 select DW_APB_TIMER 601 select APB_TIMER 602 select INTEL_SCU_IPC 603 select MFD_INTEL_MSIC 604 ---help--- 605 Select to build a kernel capable of supporting Intel MID (Mobile 606 Internet Device) platform systems which do not have the PCI legacy 607 interfaces. If you are building for a PC class system say N here. 608 609 Intel MID platforms are based on an Intel processor and chipset which 610 consume less power than most of the x86 derivatives. 611 612config X86_INTEL_QUARK 613 bool "Intel Quark platform support" 614 depends on X86_32 615 depends on X86_EXTENDED_PLATFORM 616 depends on X86_PLATFORM_DEVICES 617 depends on X86_TSC 618 depends on PCI 619 depends on PCI_GOANY 620 depends on X86_IO_APIC 621 select IOSF_MBI 622 select INTEL_IMR 623 select COMMON_CLK 624 ---help--- 625 Select to include support for Quark X1000 SoC. 626 Say Y here if you have a Quark based system such as the Arduino 627 compatible Intel Galileo. 628 629config X86_INTEL_LPSS 630 bool "Intel Low Power Subsystem Support" 631 depends on X86 && ACPI && PCI 632 select COMMON_CLK 633 select PINCTRL 634 select IOSF_MBI 635 ---help--- 636 Select to build support for Intel Low Power Subsystem such as 637 found on Intel Lynxpoint PCH. Selecting this option enables 638 things like clock tree (common clock framework) and pincontrol 639 which are needed by the LPSS peripheral drivers. 640 641config X86_AMD_PLATFORM_DEVICE 642 bool "AMD ACPI2Platform devices support" 643 depends on ACPI 644 select COMMON_CLK 645 select PINCTRL 646 ---help--- 647 Select to interpret AMD specific ACPI device to platform device 648 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 649 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 650 implemented under PINCTRL subsystem. 651 652config IOSF_MBI 653 tristate "Intel SoC IOSF Sideband support for SoC platforms" 654 depends on PCI 655 ---help--- 656 This option enables sideband register access support for Intel SoC 657 platforms. On these platforms the IOSF sideband is used in lieu of 658 MSR's for some register accesses, mostly but not limited to thermal 659 and power. Drivers may query the availability of this device to 660 determine if they need the sideband in order to work on these 661 platforms. The sideband is available on the following SoC products. 662 This list is not meant to be exclusive. 663 - BayTrail 664 - Braswell 665 - Quark 666 667 You should say Y if you are running a kernel on one of these SoC's. 668 669config IOSF_MBI_DEBUG 670 bool "Enable IOSF sideband access through debugfs" 671 depends on IOSF_MBI && DEBUG_FS 672 ---help--- 673 Select this option to expose the IOSF sideband access registers (MCR, 674 MDR, MCRX) through debugfs to write and read register information from 675 different units on the SoC. This is most useful for obtaining device 676 state information for debug and analysis. As this is a general access 677 mechanism, users of this option would have specific knowledge of the 678 device they want to access. 679 680 If you don't require the option or are in doubt, say N. 681 682config X86_RDC321X 683 bool "RDC R-321x SoC" 684 depends on X86_32 685 depends on X86_EXTENDED_PLATFORM 686 select M486 687 select X86_REBOOTFIXUPS 688 ---help--- 689 This option is needed for RDC R-321x system-on-chip, also known 690 as R-8610-(G). 691 If you don't have one of these chips, you should say N here. 692 693config X86_32_NON_STANDARD 694 bool "Support non-standard 32-bit SMP architectures" 695 depends on X86_32 && SMP 696 depends on X86_EXTENDED_PLATFORM 697 ---help--- 698 This option compiles in the bigsmp and STA2X11 default 699 subarchitectures. It is intended for a generic binary 700 kernel. If you select them all, kernel will probe it one by 701 one and will fallback to default. 702 703# Alphabetically sorted list of Non standard 32 bit platforms 704 705config X86_SUPPORTS_MEMORY_FAILURE 706 def_bool y 707 # MCE code calls memory_failure(): 708 depends on X86_MCE 709 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 710 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 711 depends on X86_64 || !SPARSEMEM 712 select ARCH_SUPPORTS_MEMORY_FAILURE 713 714config STA2X11 715 bool "STA2X11 Companion Chip Support" 716 depends on X86_32_NON_STANDARD && PCI 717 select SWIOTLB 718 select MFD_STA2X11 719 select GPIOLIB 720 ---help--- 721 This adds support for boards based on the STA2X11 IO-Hub, 722 a.k.a. "ConneXt". The chip is used in place of the standard 723 PC chipset, so all "standard" peripherals are missing. If this 724 option is selected the kernel will still be able to boot on 725 standard PC machines. 726 727config X86_32_IRIS 728 tristate "Eurobraille/Iris poweroff module" 729 depends on X86_32 730 ---help--- 731 The Iris machines from EuroBraille do not have APM or ACPI support 732 to shut themselves down properly. A special I/O sequence is 733 needed to do so, which is what this module does at 734 kernel shutdown. 735 736 This is only for Iris machines from EuroBraille. 737 738 If unused, say N. 739 740config SCHED_OMIT_FRAME_POINTER 741 def_bool y 742 prompt "Single-depth WCHAN output" 743 depends on X86 744 ---help--- 745 Calculate simpler /proc/<PID>/wchan values. If this option 746 is disabled then wchan values will recurse back to the 747 caller function. This provides more accurate wchan values, 748 at the expense of slightly more scheduling overhead. 749 750 If in doubt, say "Y". 751 752menuconfig HYPERVISOR_GUEST 753 bool "Linux guest support" 754 ---help--- 755 Say Y here to enable options for running Linux under various hyper- 756 visors. This option enables basic hypervisor detection and platform 757 setup. 758 759 If you say N, all options in this submenu will be skipped and 760 disabled, and Linux guest support won't be built in. 761 762if HYPERVISOR_GUEST 763 764config PARAVIRT 765 bool "Enable paravirtualization code" 766 ---help--- 767 This changes the kernel so it can modify itself when it is run 768 under a hypervisor, potentially improving performance significantly 769 over full virtualization. However, when run without a hypervisor 770 the kernel is theoretically slower and slightly larger. 771 772config PARAVIRT_XXL 773 bool 774 775config PARAVIRT_DEBUG 776 bool "paravirt-ops debugging" 777 depends on PARAVIRT && DEBUG_KERNEL 778 ---help--- 779 Enable to debug paravirt_ops internals. Specifically, BUG if 780 a paravirt_op is missing when it is called. 781 782config PARAVIRT_SPINLOCKS 783 bool "Paravirtualization layer for spinlocks" 784 depends on PARAVIRT && SMP 785 ---help--- 786 Paravirtualized spinlocks allow a pvops backend to replace the 787 spinlock implementation with something virtualization-friendly 788 (for example, block the virtual CPU rather than spinning). 789 790 It has a minimal impact on native kernels and gives a nice performance 791 benefit on paravirtualized KVM / Xen kernels. 792 793 If you are unsure how to answer this question, answer Y. 794 795config X86_HV_CALLBACK_VECTOR 796 def_bool n 797 798source "arch/x86/xen/Kconfig" 799 800config KVM_GUEST 801 bool "KVM Guest support (including kvmclock)" 802 depends on PARAVIRT 803 select PARAVIRT_CLOCK 804 select ARCH_CPUIDLE_HALTPOLL 805 default y 806 ---help--- 807 This option enables various optimizations for running under the KVM 808 hypervisor. It includes a paravirtualized clock, so that instead 809 of relying on a PIT (or probably other) emulation by the 810 underlying device model, the host provides the guest with 811 timing infrastructure such as time of day, and system time 812 813config ARCH_CPUIDLE_HALTPOLL 814 def_bool n 815 prompt "Disable host haltpoll when loading haltpoll driver" 816 help 817 If virtualized under KVM, disable host haltpoll. 818 819config PVH 820 bool "Support for running PVH guests" 821 ---help--- 822 This option enables the PVH entry point for guest virtual machines 823 as specified in the x86/HVM direct boot ABI. 824 825config KVM_DEBUG_FS 826 bool "Enable debug information for KVM Guests in debugfs" 827 depends on KVM_GUEST && DEBUG_FS 828 ---help--- 829 This option enables collection of various statistics for KVM guest. 830 Statistics are displayed in debugfs filesystem. Enabling this option 831 may incur significant overhead. 832 833config PARAVIRT_TIME_ACCOUNTING 834 bool "Paravirtual steal time accounting" 835 depends on PARAVIRT 836 ---help--- 837 Select this option to enable fine granularity task steal time 838 accounting. Time spent executing other tasks in parallel with 839 the current vCPU is discounted from the vCPU power. To account for 840 that, there can be a small performance impact. 841 842 If in doubt, say N here. 843 844config PARAVIRT_CLOCK 845 bool 846 847config JAILHOUSE_GUEST 848 bool "Jailhouse non-root cell support" 849 depends on X86_64 && PCI 850 select X86_PM_TIMER 851 ---help--- 852 This option allows to run Linux as guest in a Jailhouse non-root 853 cell. You can leave this option disabled if you only want to start 854 Jailhouse and run Linux afterwards in the root cell. 855 856config ACRN_GUEST 857 bool "ACRN Guest support" 858 depends on X86_64 859 select X86_HV_CALLBACK_VECTOR 860 help 861 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 862 a flexible, lightweight reference open-source hypervisor, built with 863 real-time and safety-criticality in mind. It is built for embedded 864 IOT with small footprint and real-time features. More details can be 865 found in https://projectacrn.org/. 866 867endif #HYPERVISOR_GUEST 868 869source "arch/x86/Kconfig.cpu" 870 871config HPET_TIMER 872 def_bool X86_64 873 prompt "HPET Timer Support" if X86_32 874 ---help--- 875 Use the IA-PC HPET (High Precision Event Timer) to manage 876 time in preference to the PIT and RTC, if a HPET is 877 present. 878 HPET is the next generation timer replacing legacy 8254s. 879 The HPET provides a stable time base on SMP 880 systems, unlike the TSC, but it is more expensive to access, 881 as it is off-chip. The interface used is documented 882 in the HPET spec, revision 1. 883 884 You can safely choose Y here. However, HPET will only be 885 activated if the platform and the BIOS support this feature. 886 Otherwise the 8254 will be used for timing services. 887 888 Choose N to continue using the legacy 8254 timer. 889 890config HPET_EMULATE_RTC 891 def_bool y 892 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 893 894config APB_TIMER 895 def_bool y if X86_INTEL_MID 896 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 897 select DW_APB_TIMER 898 depends on X86_INTEL_MID && SFI 899 help 900 APB timer is the replacement for 8254, HPET on X86 MID platforms. 901 The APBT provides a stable time base on SMP 902 systems, unlike the TSC, but it is more expensive to access, 903 as it is off-chip. APB timers are always running regardless of CPU 904 C states, they are used as per CPU clockevent device when possible. 905 906# Mark as expert because too many people got it wrong. 907# The code disables itself when not needed. 908config DMI 909 default y 910 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 911 bool "Enable DMI scanning" if EXPERT 912 ---help--- 913 Enabled scanning of DMI to identify machine quirks. Say Y 914 here unless you have verified that your setup is not 915 affected by entries in the DMI blacklist. Required by PNP 916 BIOS code. 917 918config GART_IOMMU 919 bool "Old AMD GART IOMMU support" 920 select IOMMU_HELPER 921 select SWIOTLB 922 depends on X86_64 && PCI && AMD_NB 923 ---help--- 924 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 925 GART based hardware IOMMUs. 926 927 The GART supports full DMA access for devices with 32-bit access 928 limitations, on systems with more than 3 GB. This is usually needed 929 for USB, sound, many IDE/SATA chipsets and some other devices. 930 931 Newer systems typically have a modern AMD IOMMU, supported via 932 the CONFIG_AMD_IOMMU=y config option. 933 934 In normal configurations this driver is only active when needed: 935 there's more than 3 GB of memory and the system contains a 936 32-bit limited device. 937 938 If unsure, say Y. 939 940config MAXSMP 941 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 942 depends on X86_64 && SMP && DEBUG_KERNEL 943 select CPUMASK_OFFSTACK 944 ---help--- 945 Enable maximum number of CPUS and NUMA Nodes for this architecture. 946 If unsure, say N. 947 948# 949# The maximum number of CPUs supported: 950# 951# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 952# and which can be configured interactively in the 953# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 954# 955# The ranges are different on 32-bit and 64-bit kernels, depending on 956# hardware capabilities and scalability features of the kernel. 957# 958# ( If MAXSMP is enabled we just use the highest possible value and disable 959# interactive configuration. ) 960# 961 962config NR_CPUS_RANGE_BEGIN 963 int 964 default NR_CPUS_RANGE_END if MAXSMP 965 default 1 if !SMP 966 default 2 967 968config NR_CPUS_RANGE_END 969 int 970 depends on X86_32 971 default 64 if SMP && X86_BIGSMP 972 default 8 if SMP && !X86_BIGSMP 973 default 1 if !SMP 974 975config NR_CPUS_RANGE_END 976 int 977 depends on X86_64 978 default 8192 if SMP && CPUMASK_OFFSTACK 979 default 512 if SMP && !CPUMASK_OFFSTACK 980 default 1 if !SMP 981 982config NR_CPUS_DEFAULT 983 int 984 depends on X86_32 985 default 32 if X86_BIGSMP 986 default 8 if SMP 987 default 1 if !SMP 988 989config NR_CPUS_DEFAULT 990 int 991 depends on X86_64 992 default 8192 if MAXSMP 993 default 64 if SMP 994 default 1 if !SMP 995 996config NR_CPUS 997 int "Maximum number of CPUs" if SMP && !MAXSMP 998 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 999 default NR_CPUS_DEFAULT 1000 ---help--- 1001 This allows you to specify the maximum number of CPUs which this 1002 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1003 supported value is 8192, otherwise the maximum value is 512. The 1004 minimum value which makes sense is 2. 1005 1006 This is purely to save memory: each supported CPU adds about 8KB 1007 to the kernel image. 1008 1009config SCHED_SMT 1010 def_bool y if SMP 1011 1012config SCHED_MC 1013 def_bool y 1014 prompt "Multi-core scheduler support" 1015 depends on SMP 1016 ---help--- 1017 Multi-core scheduler support improves the CPU scheduler's decision 1018 making when dealing with multi-core CPU chips at a cost of slightly 1019 increased overhead in some places. If unsure say N here. 1020 1021config SCHED_MC_PRIO 1022 bool "CPU core priorities scheduler support" 1023 depends on SCHED_MC && CPU_SUP_INTEL 1024 select X86_INTEL_PSTATE 1025 select CPU_FREQ 1026 default y 1027 ---help--- 1028 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1029 core ordering determined at manufacturing time, which allows 1030 certain cores to reach higher turbo frequencies (when running 1031 single threaded workloads) than others. 1032 1033 Enabling this kernel feature teaches the scheduler about 1034 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1035 scheduler's CPU selection logic accordingly, so that higher 1036 overall system performance can be achieved. 1037 1038 This feature will have no effect on CPUs without this feature. 1039 1040 If unsure say Y here. 1041 1042config UP_LATE_INIT 1043 def_bool y 1044 depends on !SMP && X86_LOCAL_APIC 1045 1046config X86_UP_APIC 1047 bool "Local APIC support on uniprocessors" if !PCI_MSI 1048 default PCI_MSI 1049 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1050 ---help--- 1051 A local APIC (Advanced Programmable Interrupt Controller) is an 1052 integrated interrupt controller in the CPU. If you have a single-CPU 1053 system which has a processor with a local APIC, you can say Y here to 1054 enable and use it. If you say Y here even though your machine doesn't 1055 have a local APIC, then the kernel will still run with no slowdown at 1056 all. The local APIC supports CPU-generated self-interrupts (timer, 1057 performance counters), and the NMI watchdog which detects hard 1058 lockups. 1059 1060config X86_UP_IOAPIC 1061 bool "IO-APIC support on uniprocessors" 1062 depends on X86_UP_APIC 1063 ---help--- 1064 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1065 SMP-capable replacement for PC-style interrupt controllers. Most 1066 SMP systems and many recent uniprocessor systems have one. 1067 1068 If you have a single-CPU system with an IO-APIC, you can say Y here 1069 to use it. If you say Y here even though your machine doesn't have 1070 an IO-APIC, then the kernel will still run with no slowdown at all. 1071 1072config X86_LOCAL_APIC 1073 def_bool y 1074 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1075 select IRQ_DOMAIN_HIERARCHY 1076 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1077 1078config X86_IO_APIC 1079 def_bool y 1080 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1081 1082config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1083 bool "Reroute for broken boot IRQs" 1084 depends on X86_IO_APIC 1085 ---help--- 1086 This option enables a workaround that fixes a source of 1087 spurious interrupts. This is recommended when threaded 1088 interrupt handling is used on systems where the generation of 1089 superfluous "boot interrupts" cannot be disabled. 1090 1091 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1092 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1093 kernel does during interrupt handling). On chipsets where this 1094 boot IRQ generation cannot be disabled, this workaround keeps 1095 the original IRQ line masked so that only the equivalent "boot 1096 IRQ" is delivered to the CPUs. The workaround also tells the 1097 kernel to set up the IRQ handler on the boot IRQ line. In this 1098 way only one interrupt is delivered to the kernel. Otherwise 1099 the spurious second interrupt may cause the kernel to bring 1100 down (vital) interrupt lines. 1101 1102 Only affects "broken" chipsets. Interrupt sharing may be 1103 increased on these systems. 1104 1105config X86_MCE 1106 bool "Machine Check / overheating reporting" 1107 select GENERIC_ALLOCATOR 1108 default y 1109 ---help--- 1110 Machine Check support allows the processor to notify the 1111 kernel if it detects a problem (e.g. overheating, data corruption). 1112 The action the kernel takes depends on the severity of the problem, 1113 ranging from warning messages to halting the machine. 1114 1115config X86_MCELOG_LEGACY 1116 bool "Support for deprecated /dev/mcelog character device" 1117 depends on X86_MCE 1118 ---help--- 1119 Enable support for /dev/mcelog which is needed by the old mcelog 1120 userspace logging daemon. Consider switching to the new generation 1121 rasdaemon solution. 1122 1123config X86_MCE_INTEL 1124 def_bool y 1125 prompt "Intel MCE features" 1126 depends on X86_MCE && X86_LOCAL_APIC 1127 ---help--- 1128 Additional support for intel specific MCE features such as 1129 the thermal monitor. 1130 1131config X86_MCE_AMD 1132 def_bool y 1133 prompt "AMD MCE features" 1134 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1135 ---help--- 1136 Additional support for AMD specific MCE features such as 1137 the DRAM Error Threshold. 1138 1139config X86_ANCIENT_MCE 1140 bool "Support for old Pentium 5 / WinChip machine checks" 1141 depends on X86_32 && X86_MCE 1142 ---help--- 1143 Include support for machine check handling on old Pentium 5 or WinChip 1144 systems. These typically need to be enabled explicitly on the command 1145 line. 1146 1147config X86_MCE_THRESHOLD 1148 depends on X86_MCE_AMD || X86_MCE_INTEL 1149 def_bool y 1150 1151config X86_MCE_INJECT 1152 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1153 tristate "Machine check injector support" 1154 ---help--- 1155 Provide support for injecting machine checks for testing purposes. 1156 If you don't know what a machine check is and you don't do kernel 1157 QA it is safe to say n. 1158 1159config X86_THERMAL_VECTOR 1160 def_bool y 1161 depends on X86_MCE_INTEL 1162 1163source "arch/x86/events/Kconfig" 1164 1165config X86_LEGACY_VM86 1166 bool "Legacy VM86 support" 1167 depends on X86_32 1168 ---help--- 1169 This option allows user programs to put the CPU into V8086 1170 mode, which is an 80286-era approximation of 16-bit real mode. 1171 1172 Some very old versions of X and/or vbetool require this option 1173 for user mode setting. Similarly, DOSEMU will use it if 1174 available to accelerate real mode DOS programs. However, any 1175 recent version of DOSEMU, X, or vbetool should be fully 1176 functional even without kernel VM86 support, as they will all 1177 fall back to software emulation. Nevertheless, if you are using 1178 a 16-bit DOS program where 16-bit performance matters, vm86 1179 mode might be faster than emulation and you might want to 1180 enable this option. 1181 1182 Note that any app that works on a 64-bit kernel is unlikely to 1183 need this option, as 64-bit kernels don't, and can't, support 1184 V8086 mode. This option is also unrelated to 16-bit protected 1185 mode and is not needed to run most 16-bit programs under Wine. 1186 1187 Enabling this option increases the complexity of the kernel 1188 and slows down exception handling a tiny bit. 1189 1190 If unsure, say N here. 1191 1192config VM86 1193 bool 1194 default X86_LEGACY_VM86 1195 1196config X86_16BIT 1197 bool "Enable support for 16-bit segments" if EXPERT 1198 default y 1199 depends on MODIFY_LDT_SYSCALL 1200 ---help--- 1201 This option is required by programs like Wine to run 16-bit 1202 protected mode legacy code on x86 processors. Disabling 1203 this option saves about 300 bytes on i386, or around 6K text 1204 plus 16K runtime memory on x86-64, 1205 1206config X86_ESPFIX32 1207 def_bool y 1208 depends on X86_16BIT && X86_32 1209 1210config X86_ESPFIX64 1211 def_bool y 1212 depends on X86_16BIT && X86_64 1213 1214config X86_VSYSCALL_EMULATION 1215 bool "Enable vsyscall emulation" if EXPERT 1216 default y 1217 depends on X86_64 1218 ---help--- 1219 This enables emulation of the legacy vsyscall page. Disabling 1220 it is roughly equivalent to booting with vsyscall=none, except 1221 that it will also disable the helpful warning if a program 1222 tries to use a vsyscall. With this option set to N, offending 1223 programs will just segfault, citing addresses of the form 1224 0xffffffffff600?00. 1225 1226 This option is required by many programs built before 2013, and 1227 care should be used even with newer programs if set to N. 1228 1229 Disabling this option saves about 7K of kernel size and 1230 possibly 4K of additional runtime pagetable memory. 1231 1232config X86_IOPL_IOPERM 1233 bool "IOPERM and IOPL Emulation" 1234 default y 1235 ---help--- 1236 This enables the ioperm() and iopl() syscalls which are necessary 1237 for legacy applications. 1238 1239 Legacy IOPL support is an overbroad mechanism which allows user 1240 space aside of accessing all 65536 I/O ports also to disable 1241 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1242 capabilities and permission from potentially active security 1243 modules. 1244 1245 The emulation restricts the functionality of the syscall to 1246 only allowing the full range I/O port access, but prevents the 1247 ability to disable interrupts from user space which would be 1248 granted if the hardware IOPL mechanism would be used. 1249 1250config TOSHIBA 1251 tristate "Toshiba Laptop support" 1252 depends on X86_32 1253 ---help--- 1254 This adds a driver to safely access the System Management Mode of 1255 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1256 not work on models with a Phoenix BIOS. The System Management Mode 1257 is used to set the BIOS and power saving options on Toshiba portables. 1258 1259 For information on utilities to make use of this driver see the 1260 Toshiba Linux utilities web site at: 1261 <http://www.buzzard.org.uk/toshiba/>. 1262 1263 Say Y if you intend to run this kernel on a Toshiba portable. 1264 Say N otherwise. 1265 1266config I8K 1267 tristate "Dell i8k legacy laptop support" 1268 select HWMON 1269 select SENSORS_DELL_SMM 1270 ---help--- 1271 This option enables legacy /proc/i8k userspace interface in hwmon 1272 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1273 temperature and allows controlling fan speeds of Dell laptops via 1274 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1275 it reports also power and hotkey status. For fan speed control is 1276 needed userspace package i8kutils. 1277 1278 Say Y if you intend to run this kernel on old Dell laptops or want to 1279 use userspace package i8kutils. 1280 Say N otherwise. 1281 1282config X86_REBOOTFIXUPS 1283 bool "Enable X86 board specific fixups for reboot" 1284 depends on X86_32 1285 ---help--- 1286 This enables chipset and/or board specific fixups to be done 1287 in order to get reboot to work correctly. This is only needed on 1288 some combinations of hardware and BIOS. The symptom, for which 1289 this config is intended, is when reboot ends with a stalled/hung 1290 system. 1291 1292 Currently, the only fixup is for the Geode machines using 1293 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1294 1295 Say Y if you want to enable the fixup. Currently, it's safe to 1296 enable this option even if you don't need it. 1297 Say N otherwise. 1298 1299config MICROCODE 1300 bool "CPU microcode loading support" 1301 default y 1302 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1303 select FW_LOADER 1304 ---help--- 1305 If you say Y here, you will be able to update the microcode on 1306 Intel and AMD processors. The Intel support is for the IA32 family, 1307 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1308 AMD support is for families 0x10 and later. You will obviously need 1309 the actual microcode binary data itself which is not shipped with 1310 the Linux kernel. 1311 1312 The preferred method to load microcode from a detached initrd is described 1313 in Documentation/x86/microcode.rst. For that you need to enable 1314 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1315 initrd for microcode blobs. 1316 1317 In addition, you can build the microcode into the kernel. For that you 1318 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1319 config option. 1320 1321config MICROCODE_INTEL 1322 bool "Intel microcode loading support" 1323 depends on MICROCODE 1324 default MICROCODE 1325 select FW_LOADER 1326 ---help--- 1327 This options enables microcode patch loading support for Intel 1328 processors. 1329 1330 For the current Intel microcode data package go to 1331 <https://downloadcenter.intel.com> and search for 1332 'Linux Processor Microcode Data File'. 1333 1334config MICROCODE_AMD 1335 bool "AMD microcode loading support" 1336 depends on MICROCODE 1337 select FW_LOADER 1338 ---help--- 1339 If you select this option, microcode patch loading support for AMD 1340 processors will be enabled. 1341 1342config MICROCODE_OLD_INTERFACE 1343 bool "Ancient loading interface (DEPRECATED)" 1344 default n 1345 depends on MICROCODE 1346 ---help--- 1347 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1348 which was used by userspace tools like iucode_tool and microcode.ctl. 1349 It is inadequate because it runs too late to be able to properly 1350 load microcode on a machine and it needs special tools. Instead, you 1351 should've switched to the early loading method with the initrd or 1352 builtin microcode by now: Documentation/x86/microcode.rst 1353 1354config X86_MSR 1355 tristate "/dev/cpu/*/msr - Model-specific register support" 1356 ---help--- 1357 This device gives privileged processes access to the x86 1358 Model-Specific Registers (MSRs). It is a character device with 1359 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1360 MSR accesses are directed to a specific CPU on multi-processor 1361 systems. 1362 1363config X86_CPUID 1364 tristate "/dev/cpu/*/cpuid - CPU information support" 1365 ---help--- 1366 This device gives processes access to the x86 CPUID instruction to 1367 be executed on a specific processor. It is a character device 1368 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1369 /dev/cpu/31/cpuid. 1370 1371choice 1372 prompt "High Memory Support" 1373 default HIGHMEM4G 1374 depends on X86_32 1375 1376config NOHIGHMEM 1377 bool "off" 1378 ---help--- 1379 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1380 However, the address space of 32-bit x86 processors is only 4 1381 Gigabytes large. That means that, if you have a large amount of 1382 physical memory, not all of it can be "permanently mapped" by the 1383 kernel. The physical memory that's not permanently mapped is called 1384 "high memory". 1385 1386 If you are compiling a kernel which will never run on a machine with 1387 more than 1 Gigabyte total physical RAM, answer "off" here (default 1388 choice and suitable for most users). This will result in a "3GB/1GB" 1389 split: 3GB are mapped so that each process sees a 3GB virtual memory 1390 space and the remaining part of the 4GB virtual memory space is used 1391 by the kernel to permanently map as much physical memory as 1392 possible. 1393 1394 If the machine has between 1 and 4 Gigabytes physical RAM, then 1395 answer "4GB" here. 1396 1397 If more than 4 Gigabytes is used then answer "64GB" here. This 1398 selection turns Intel PAE (Physical Address Extension) mode on. 1399 PAE implements 3-level paging on IA32 processors. PAE is fully 1400 supported by Linux, PAE mode is implemented on all recent Intel 1401 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1402 then the kernel will not boot on CPUs that don't support PAE! 1403 1404 The actual amount of total physical memory will either be 1405 auto detected or can be forced by using a kernel command line option 1406 such as "mem=256M". (Try "man bootparam" or see the documentation of 1407 your boot loader (lilo or loadlin) about how to pass options to the 1408 kernel at boot time.) 1409 1410 If unsure, say "off". 1411 1412config HIGHMEM4G 1413 bool "4GB" 1414 ---help--- 1415 Select this if you have a 32-bit processor and between 1 and 4 1416 gigabytes of physical RAM. 1417 1418config HIGHMEM64G 1419 bool "64GB" 1420 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1421 select X86_PAE 1422 ---help--- 1423 Select this if you have a 32-bit processor and more than 4 1424 gigabytes of physical RAM. 1425 1426endchoice 1427 1428choice 1429 prompt "Memory split" if EXPERT 1430 default VMSPLIT_3G 1431 depends on X86_32 1432 ---help--- 1433 Select the desired split between kernel and user memory. 1434 1435 If the address range available to the kernel is less than the 1436 physical memory installed, the remaining memory will be available 1437 as "high memory". Accessing high memory is a little more costly 1438 than low memory, as it needs to be mapped into the kernel first. 1439 Note that increasing the kernel address space limits the range 1440 available to user programs, making the address space there 1441 tighter. Selecting anything other than the default 3G/1G split 1442 will also likely make your kernel incompatible with binary-only 1443 kernel modules. 1444 1445 If you are not absolutely sure what you are doing, leave this 1446 option alone! 1447 1448 config VMSPLIT_3G 1449 bool "3G/1G user/kernel split" 1450 config VMSPLIT_3G_OPT 1451 depends on !X86_PAE 1452 bool "3G/1G user/kernel split (for full 1G low memory)" 1453 config VMSPLIT_2G 1454 bool "2G/2G user/kernel split" 1455 config VMSPLIT_2G_OPT 1456 depends on !X86_PAE 1457 bool "2G/2G user/kernel split (for full 2G low memory)" 1458 config VMSPLIT_1G 1459 bool "1G/3G user/kernel split" 1460endchoice 1461 1462config PAGE_OFFSET 1463 hex 1464 default 0xB0000000 if VMSPLIT_3G_OPT 1465 default 0x80000000 if VMSPLIT_2G 1466 default 0x78000000 if VMSPLIT_2G_OPT 1467 default 0x40000000 if VMSPLIT_1G 1468 default 0xC0000000 1469 depends on X86_32 1470 1471config HIGHMEM 1472 def_bool y 1473 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1474 1475config X86_PAE 1476 bool "PAE (Physical Address Extension) Support" 1477 depends on X86_32 && !HIGHMEM4G 1478 select PHYS_ADDR_T_64BIT 1479 select SWIOTLB 1480 ---help--- 1481 PAE is required for NX support, and furthermore enables 1482 larger swapspace support for non-overcommit purposes. It 1483 has the cost of more pagetable lookup overhead, and also 1484 consumes more pagetable space per process. 1485 1486config X86_5LEVEL 1487 bool "Enable 5-level page tables support" 1488 default y 1489 select DYNAMIC_MEMORY_LAYOUT 1490 select SPARSEMEM_VMEMMAP 1491 depends on X86_64 1492 ---help--- 1493 5-level paging enables access to larger address space: 1494 upto 128 PiB of virtual address space and 4 PiB of 1495 physical address space. 1496 1497 It will be supported by future Intel CPUs. 1498 1499 A kernel with the option enabled can be booted on machines that 1500 support 4- or 5-level paging. 1501 1502 See Documentation/x86/x86_64/5level-paging.rst for more 1503 information. 1504 1505 Say N if unsure. 1506 1507config X86_DIRECT_GBPAGES 1508 def_bool y 1509 depends on X86_64 1510 ---help--- 1511 Certain kernel features effectively disable kernel 1512 linear 1 GB mappings (even if the CPU otherwise 1513 supports them), so don't confuse the user by printing 1514 that we have them enabled. 1515 1516config X86_CPA_STATISTICS 1517 bool "Enable statistic for Change Page Attribute" 1518 depends on DEBUG_FS 1519 ---help--- 1520 Expose statistics about the Change Page Attribute mechanism, which 1521 helps to determine the effectiveness of preserving large and huge 1522 page mappings when mapping protections are changed. 1523 1524config AMD_MEM_ENCRYPT 1525 bool "AMD Secure Memory Encryption (SME) support" 1526 depends on X86_64 && CPU_SUP_AMD 1527 select DYNAMIC_PHYSICAL_MASK 1528 select ARCH_USE_MEMREMAP_PROT 1529 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1530 ---help--- 1531 Say yes to enable support for the encryption of system memory. 1532 This requires an AMD processor that supports Secure Memory 1533 Encryption (SME). 1534 1535config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1536 bool "Activate AMD Secure Memory Encryption (SME) by default" 1537 default y 1538 depends on AMD_MEM_ENCRYPT 1539 ---help--- 1540 Say yes to have system memory encrypted by default if running on 1541 an AMD processor that supports Secure Memory Encryption (SME). 1542 1543 If set to Y, then the encryption of system memory can be 1544 deactivated with the mem_encrypt=off command line option. 1545 1546 If set to N, then the encryption of system memory can be 1547 activated with the mem_encrypt=on command line option. 1548 1549# Common NUMA Features 1550config NUMA 1551 bool "NUMA Memory Allocation and Scheduler Support" 1552 depends on SMP 1553 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1554 default y if X86_BIGSMP 1555 ---help--- 1556 Enable NUMA (Non-Uniform Memory Access) support. 1557 1558 The kernel will try to allocate memory used by a CPU on the 1559 local memory controller of the CPU and add some more 1560 NUMA awareness to the kernel. 1561 1562 For 64-bit this is recommended if the system is Intel Core i7 1563 (or later), AMD Opteron, or EM64T NUMA. 1564 1565 For 32-bit this is only needed if you boot a 32-bit 1566 kernel on a 64-bit NUMA platform. 1567 1568 Otherwise, you should say N. 1569 1570config AMD_NUMA 1571 def_bool y 1572 prompt "Old style AMD Opteron NUMA detection" 1573 depends on X86_64 && NUMA && PCI 1574 ---help--- 1575 Enable AMD NUMA node topology detection. You should say Y here if 1576 you have a multi processor AMD system. This uses an old method to 1577 read the NUMA configuration directly from the builtin Northbridge 1578 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1579 which also takes priority if both are compiled in. 1580 1581config X86_64_ACPI_NUMA 1582 def_bool y 1583 prompt "ACPI NUMA detection" 1584 depends on X86_64 && NUMA && ACPI && PCI 1585 select ACPI_NUMA 1586 ---help--- 1587 Enable ACPI SRAT based node topology detection. 1588 1589# Some NUMA nodes have memory ranges that span 1590# other nodes. Even though a pfn is valid and 1591# between a node's start and end pfns, it may not 1592# reside on that node. See memmap_init_zone() 1593# for details. 1594config NODES_SPAN_OTHER_NODES 1595 def_bool y 1596 depends on X86_64_ACPI_NUMA 1597 1598config NUMA_EMU 1599 bool "NUMA emulation" 1600 depends on NUMA 1601 ---help--- 1602 Enable NUMA emulation. A flat machine will be split 1603 into virtual nodes when booted with "numa=fake=N", where N is the 1604 number of nodes. This is only useful for debugging. 1605 1606config NODES_SHIFT 1607 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1608 range 1 10 1609 default "10" if MAXSMP 1610 default "6" if X86_64 1611 default "3" 1612 depends on NEED_MULTIPLE_NODES 1613 ---help--- 1614 Specify the maximum number of NUMA Nodes available on the target 1615 system. Increases memory reserved to accommodate various tables. 1616 1617config ARCH_HAVE_MEMORY_PRESENT 1618 def_bool y 1619 depends on X86_32 && DISCONTIGMEM 1620 1621config ARCH_FLATMEM_ENABLE 1622 def_bool y 1623 depends on X86_32 && !NUMA 1624 1625config ARCH_DISCONTIGMEM_ENABLE 1626 def_bool n 1627 depends on NUMA && X86_32 1628 depends on BROKEN 1629 1630config ARCH_SPARSEMEM_ENABLE 1631 def_bool y 1632 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1633 select SPARSEMEM_STATIC if X86_32 1634 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1635 1636config ARCH_SPARSEMEM_DEFAULT 1637 def_bool X86_64 || (NUMA && X86_32) 1638 1639config ARCH_SELECT_MEMORY_MODEL 1640 def_bool y 1641 depends on ARCH_SPARSEMEM_ENABLE 1642 1643config ARCH_MEMORY_PROBE 1644 bool "Enable sysfs memory/probe interface" 1645 depends on X86_64 && MEMORY_HOTPLUG 1646 help 1647 This option enables a sysfs memory/probe interface for testing. 1648 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1649 If you are unsure how to answer this question, answer N. 1650 1651config ARCH_PROC_KCORE_TEXT 1652 def_bool y 1653 depends on X86_64 && PROC_KCORE 1654 1655config ILLEGAL_POINTER_VALUE 1656 hex 1657 default 0 if X86_32 1658 default 0xdead000000000000 if X86_64 1659 1660config X86_PMEM_LEGACY_DEVICE 1661 bool 1662 1663config X86_PMEM_LEGACY 1664 tristate "Support non-standard NVDIMMs and ADR protected memory" 1665 depends on PHYS_ADDR_T_64BIT 1666 depends on BLK_DEV 1667 select X86_PMEM_LEGACY_DEVICE 1668 select LIBNVDIMM 1669 help 1670 Treat memory marked using the non-standard e820 type of 12 as used 1671 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1672 The kernel will offer these regions to the 'pmem' driver so 1673 they can be used for persistent storage. 1674 1675 Say Y if unsure. 1676 1677config HIGHPTE 1678 bool "Allocate 3rd-level pagetables from highmem" 1679 depends on HIGHMEM 1680 ---help--- 1681 The VM uses one page table entry for each page of physical memory. 1682 For systems with a lot of RAM, this can be wasteful of precious 1683 low memory. Setting this option will put user-space page table 1684 entries in high memory. 1685 1686config X86_CHECK_BIOS_CORRUPTION 1687 bool "Check for low memory corruption" 1688 ---help--- 1689 Periodically check for memory corruption in low memory, which 1690 is suspected to be caused by BIOS. Even when enabled in the 1691 configuration, it is disabled at runtime. Enable it by 1692 setting "memory_corruption_check=1" on the kernel command 1693 line. By default it scans the low 64k of memory every 60 1694 seconds; see the memory_corruption_check_size and 1695 memory_corruption_check_period parameters in 1696 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1697 1698 When enabled with the default parameters, this option has 1699 almost no overhead, as it reserves a relatively small amount 1700 of memory and scans it infrequently. It both detects corruption 1701 and prevents it from affecting the running system. 1702 1703 It is, however, intended as a diagnostic tool; if repeatable 1704 BIOS-originated corruption always affects the same memory, 1705 you can use memmap= to prevent the kernel from using that 1706 memory. 1707 1708config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1709 bool "Set the default setting of memory_corruption_check" 1710 depends on X86_CHECK_BIOS_CORRUPTION 1711 default y 1712 ---help--- 1713 Set whether the default state of memory_corruption_check is 1714 on or off. 1715 1716config X86_RESERVE_LOW 1717 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1718 default 64 1719 range 4 640 1720 ---help--- 1721 Specify the amount of low memory to reserve for the BIOS. 1722 1723 The first page contains BIOS data structures that the kernel 1724 must not use, so that page must always be reserved. 1725 1726 By default we reserve the first 64K of physical RAM, as a 1727 number of BIOSes are known to corrupt that memory range 1728 during events such as suspend/resume or monitor cable 1729 insertion, so it must not be used by the kernel. 1730 1731 You can set this to 4 if you are absolutely sure that you 1732 trust the BIOS to get all its memory reservations and usages 1733 right. If you know your BIOS have problems beyond the 1734 default 64K area, you can set this to 640 to avoid using the 1735 entire low memory range. 1736 1737 If you have doubts about the BIOS (e.g. suspend/resume does 1738 not work or there's kernel crashes after certain hardware 1739 hotplug events) then you might want to enable 1740 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1741 typical corruption patterns. 1742 1743 Leave this to the default value of 64 if you are unsure. 1744 1745config MATH_EMULATION 1746 bool 1747 depends on MODIFY_LDT_SYSCALL 1748 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1749 ---help--- 1750 Linux can emulate a math coprocessor (used for floating point 1751 operations) if you don't have one. 486DX and Pentium processors have 1752 a math coprocessor built in, 486SX and 386 do not, unless you added 1753 a 487DX or 387, respectively. (The messages during boot time can 1754 give you some hints here ["man dmesg"].) Everyone needs either a 1755 coprocessor or this emulation. 1756 1757 If you don't have a math coprocessor, you need to say Y here; if you 1758 say Y here even though you have a coprocessor, the coprocessor will 1759 be used nevertheless. (This behavior can be changed with the kernel 1760 command line option "no387", which comes handy if your coprocessor 1761 is broken. Try "man bootparam" or see the documentation of your boot 1762 loader (lilo or loadlin) about how to pass options to the kernel at 1763 boot time.) This means that it is a good idea to say Y here if you 1764 intend to use this kernel on different machines. 1765 1766 More information about the internals of the Linux math coprocessor 1767 emulation can be found in <file:arch/x86/math-emu/README>. 1768 1769 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1770 kernel, it won't hurt. 1771 1772config MTRR 1773 def_bool y 1774 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1775 ---help--- 1776 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1777 the Memory Type Range Registers (MTRRs) may be used to control 1778 processor access to memory ranges. This is most useful if you have 1779 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1780 allows bus write transfers to be combined into a larger transfer 1781 before bursting over the PCI/AGP bus. This can increase performance 1782 of image write operations 2.5 times or more. Saying Y here creates a 1783 /proc/mtrr file which may be used to manipulate your processor's 1784 MTRRs. Typically the X server should use this. 1785 1786 This code has a reasonably generic interface so that similar 1787 control registers on other processors can be easily supported 1788 as well: 1789 1790 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1791 Registers (ARRs) which provide a similar functionality to MTRRs. For 1792 these, the ARRs are used to emulate the MTRRs. 1793 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1794 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1795 write-combining. All of these processors are supported by this code 1796 and it makes sense to say Y here if you have one of them. 1797 1798 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1799 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1800 can lead to all sorts of problems, so it's good to say Y here. 1801 1802 You can safely say Y even if your machine doesn't have MTRRs, you'll 1803 just add about 9 KB to your kernel. 1804 1805 See <file:Documentation/x86/mtrr.rst> for more information. 1806 1807config MTRR_SANITIZER 1808 def_bool y 1809 prompt "MTRR cleanup support" 1810 depends on MTRR 1811 ---help--- 1812 Convert MTRR layout from continuous to discrete, so X drivers can 1813 add writeback entries. 1814 1815 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1816 The largest mtrr entry size for a continuous block can be set with 1817 mtrr_chunk_size. 1818 1819 If unsure, say Y. 1820 1821config MTRR_SANITIZER_ENABLE_DEFAULT 1822 int "MTRR cleanup enable value (0-1)" 1823 range 0 1 1824 default "0" 1825 depends on MTRR_SANITIZER 1826 ---help--- 1827 Enable mtrr cleanup default value 1828 1829config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1830 int "MTRR cleanup spare reg num (0-7)" 1831 range 0 7 1832 default "1" 1833 depends on MTRR_SANITIZER 1834 ---help--- 1835 mtrr cleanup spare entries default, it can be changed via 1836 mtrr_spare_reg_nr=N on the kernel command line. 1837 1838config X86_PAT 1839 def_bool y 1840 prompt "x86 PAT support" if EXPERT 1841 depends on MTRR 1842 ---help--- 1843 Use PAT attributes to setup page level cache control. 1844 1845 PATs are the modern equivalents of MTRRs and are much more 1846 flexible than MTRRs. 1847 1848 Say N here if you see bootup problems (boot crash, boot hang, 1849 spontaneous reboots) or a non-working video driver. 1850 1851 If unsure, say Y. 1852 1853config ARCH_USES_PG_UNCACHED 1854 def_bool y 1855 depends on X86_PAT 1856 1857config ARCH_RANDOM 1858 def_bool y 1859 prompt "x86 architectural random number generator" if EXPERT 1860 ---help--- 1861 Enable the x86 architectural RDRAND instruction 1862 (Intel Bull Mountain technology) to generate random numbers. 1863 If supported, this is a high bandwidth, cryptographically 1864 secure hardware random number generator. 1865 1866config X86_SMAP 1867 def_bool y 1868 prompt "Supervisor Mode Access Prevention" if EXPERT 1869 ---help--- 1870 Supervisor Mode Access Prevention (SMAP) is a security 1871 feature in newer Intel processors. There is a small 1872 performance cost if this enabled and turned on; there is 1873 also a small increase in the kernel size if this is enabled. 1874 1875 If unsure, say Y. 1876 1877config X86_UMIP 1878 def_bool y 1879 depends on CPU_SUP_INTEL || CPU_SUP_AMD 1880 prompt "User Mode Instruction Prevention" if EXPERT 1881 ---help--- 1882 User Mode Instruction Prevention (UMIP) is a security feature in 1883 some x86 processors. If enabled, a general protection fault is 1884 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1885 executed in user mode. These instructions unnecessarily expose 1886 information about the hardware state. 1887 1888 The vast majority of applications do not use these instructions. 1889 For the very few that do, software emulation is provided in 1890 specific cases in protected and virtual-8086 modes. Emulated 1891 results are dummy. 1892 1893config X86_INTEL_MEMORY_PROTECTION_KEYS 1894 prompt "Intel Memory Protection Keys" 1895 def_bool y 1896 # Note: only available in 64-bit mode 1897 depends on CPU_SUP_INTEL && X86_64 1898 select ARCH_USES_HIGH_VMA_FLAGS 1899 select ARCH_HAS_PKEYS 1900 ---help--- 1901 Memory Protection Keys provides a mechanism for enforcing 1902 page-based protections, but without requiring modification of the 1903 page tables when an application changes protection domains. 1904 1905 For details, see Documentation/core-api/protection-keys.rst 1906 1907 If unsure, say y. 1908 1909choice 1910 prompt "TSX enable mode" 1911 depends on CPU_SUP_INTEL 1912 default X86_INTEL_TSX_MODE_OFF 1913 help 1914 Intel's TSX (Transactional Synchronization Extensions) feature 1915 allows to optimize locking protocols through lock elision which 1916 can lead to a noticeable performance boost. 1917 1918 On the other hand it has been shown that TSX can be exploited 1919 to form side channel attacks (e.g. TAA) and chances are there 1920 will be more of those attacks discovered in the future. 1921 1922 Therefore TSX is not enabled by default (aka tsx=off). An admin 1923 might override this decision by tsx=on the command line parameter. 1924 Even with TSX enabled, the kernel will attempt to enable the best 1925 possible TAA mitigation setting depending on the microcode available 1926 for the particular machine. 1927 1928 This option allows to set the default tsx mode between tsx=on, =off 1929 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1930 details. 1931 1932 Say off if not sure, auto if TSX is in use but it should be used on safe 1933 platforms or on if TSX is in use and the security aspect of tsx is not 1934 relevant. 1935 1936config X86_INTEL_TSX_MODE_OFF 1937 bool "off" 1938 help 1939 TSX is disabled if possible - equals to tsx=off command line parameter. 1940 1941config X86_INTEL_TSX_MODE_ON 1942 bool "on" 1943 help 1944 TSX is always enabled on TSX capable HW - equals the tsx=on command 1945 line parameter. 1946 1947config X86_INTEL_TSX_MODE_AUTO 1948 bool "auto" 1949 help 1950 TSX is enabled on TSX capable HW that is believed to be safe against 1951 side channel attacks- equals the tsx=auto command line parameter. 1952endchoice 1953 1954config EFI 1955 bool "EFI runtime service support" 1956 depends on ACPI 1957 select UCS2_STRING 1958 select EFI_RUNTIME_WRAPPERS 1959 ---help--- 1960 This enables the kernel to use EFI runtime services that are 1961 available (such as the EFI variable services). 1962 1963 This option is only useful on systems that have EFI firmware. 1964 In addition, you should use the latest ELILO loader available 1965 at <http://elilo.sourceforge.net> in order to take advantage 1966 of EFI runtime services. However, even with this option, the 1967 resultant kernel should continue to boot on existing non-EFI 1968 platforms. 1969 1970config EFI_STUB 1971 bool "EFI stub support" 1972 depends on EFI && !X86_USE_3DNOW 1973 depends on $(cc-option,-mabi=ms) || X86_32 1974 select RELOCATABLE 1975 ---help--- 1976 This kernel feature allows a bzImage to be loaded directly 1977 by EFI firmware without the use of a bootloader. 1978 1979 See Documentation/admin-guide/efi-stub.rst for more information. 1980 1981config EFI_MIXED 1982 bool "EFI mixed-mode support" 1983 depends on EFI_STUB && X86_64 1984 ---help--- 1985 Enabling this feature allows a 64-bit kernel to be booted 1986 on a 32-bit firmware, provided that your CPU supports 64-bit 1987 mode. 1988 1989 Note that it is not possible to boot a mixed-mode enabled 1990 kernel via the EFI boot stub - a bootloader that supports 1991 the EFI handover protocol must be used. 1992 1993 If unsure, say N. 1994 1995config SECCOMP 1996 def_bool y 1997 prompt "Enable seccomp to safely compute untrusted bytecode" 1998 ---help--- 1999 This kernel feature is useful for number crunching applications 2000 that may need to compute untrusted bytecode during their 2001 execution. By using pipes or other transports made available to 2002 the process as file descriptors supporting the read/write 2003 syscalls, it's possible to isolate those applications in 2004 their own address space using seccomp. Once seccomp is 2005 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 2006 and the task is only allowed to execute a few safe syscalls 2007 defined by each seccomp mode. 2008 2009 If unsure, say Y. Only embedded should say N here. 2010 2011source "kernel/Kconfig.hz" 2012 2013config KEXEC 2014 bool "kexec system call" 2015 select KEXEC_CORE 2016 ---help--- 2017 kexec is a system call that implements the ability to shutdown your 2018 current kernel, and to start another kernel. It is like a reboot 2019 but it is independent of the system firmware. And like a reboot 2020 you can start any kernel with it, not just Linux. 2021 2022 The name comes from the similarity to the exec system call. 2023 2024 It is an ongoing process to be certain the hardware in a machine 2025 is properly shutdown, so do not be surprised if this code does not 2026 initially work for you. As of this writing the exact hardware 2027 interface is strongly in flux, so no good recommendation can be 2028 made. 2029 2030config KEXEC_FILE 2031 bool "kexec file based system call" 2032 select KEXEC_CORE 2033 select BUILD_BIN2C 2034 depends on X86_64 2035 depends on CRYPTO=y 2036 depends on CRYPTO_SHA256=y 2037 ---help--- 2038 This is new version of kexec system call. This system call is 2039 file based and takes file descriptors as system call argument 2040 for kernel and initramfs as opposed to list of segments as 2041 accepted by previous system call. 2042 2043config ARCH_HAS_KEXEC_PURGATORY 2044 def_bool KEXEC_FILE 2045 2046config KEXEC_SIG 2047 bool "Verify kernel signature during kexec_file_load() syscall" 2048 depends on KEXEC_FILE 2049 ---help--- 2050 2051 This option makes the kexec_file_load() syscall check for a valid 2052 signature of the kernel image. The image can still be loaded without 2053 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2054 there's a signature that we can check, then it must be valid. 2055 2056 In addition to this option, you need to enable signature 2057 verification for the corresponding kernel image type being 2058 loaded in order for this to work. 2059 2060config KEXEC_SIG_FORCE 2061 bool "Require a valid signature in kexec_file_load() syscall" 2062 depends on KEXEC_SIG 2063 ---help--- 2064 This option makes kernel signature verification mandatory for 2065 the kexec_file_load() syscall. 2066 2067config KEXEC_BZIMAGE_VERIFY_SIG 2068 bool "Enable bzImage signature verification support" 2069 depends on KEXEC_SIG 2070 depends on SIGNED_PE_FILE_VERIFICATION 2071 select SYSTEM_TRUSTED_KEYRING 2072 ---help--- 2073 Enable bzImage signature verification support. 2074 2075config CRASH_DUMP 2076 bool "kernel crash dumps" 2077 depends on X86_64 || (X86_32 && HIGHMEM) 2078 ---help--- 2079 Generate crash dump after being started by kexec. 2080 This should be normally only set in special crash dump kernels 2081 which are loaded in the main kernel with kexec-tools into 2082 a specially reserved region and then later executed after 2083 a crash by kdump/kexec. The crash dump kernel must be compiled 2084 to a memory address not used by the main kernel or BIOS using 2085 PHYSICAL_START, or it must be built as a relocatable image 2086 (CONFIG_RELOCATABLE=y). 2087 For more details see Documentation/admin-guide/kdump/kdump.rst 2088 2089config KEXEC_JUMP 2090 bool "kexec jump" 2091 depends on KEXEC && HIBERNATION 2092 ---help--- 2093 Jump between original kernel and kexeced kernel and invoke 2094 code in physical address mode via KEXEC 2095 2096config PHYSICAL_START 2097 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2098 default "0x1000000" 2099 ---help--- 2100 This gives the physical address where the kernel is loaded. 2101 2102 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2103 bzImage will decompress itself to above physical address and 2104 run from there. Otherwise, bzImage will run from the address where 2105 it has been loaded by the boot loader and will ignore above physical 2106 address. 2107 2108 In normal kdump cases one does not have to set/change this option 2109 as now bzImage can be compiled as a completely relocatable image 2110 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2111 address. This option is mainly useful for the folks who don't want 2112 to use a bzImage for capturing the crash dump and want to use a 2113 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2114 to be specifically compiled to run from a specific memory area 2115 (normally a reserved region) and this option comes handy. 2116 2117 So if you are using bzImage for capturing the crash dump, 2118 leave the value here unchanged to 0x1000000 and set 2119 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2120 for capturing the crash dump change this value to start of 2121 the reserved region. In other words, it can be set based on 2122 the "X" value as specified in the "crashkernel=YM@XM" 2123 command line boot parameter passed to the panic-ed 2124 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2125 for more details about crash dumps. 2126 2127 Usage of bzImage for capturing the crash dump is recommended as 2128 one does not have to build two kernels. Same kernel can be used 2129 as production kernel and capture kernel. Above option should have 2130 gone away after relocatable bzImage support is introduced. But it 2131 is present because there are users out there who continue to use 2132 vmlinux for dump capture. This option should go away down the 2133 line. 2134 2135 Don't change this unless you know what you are doing. 2136 2137config RELOCATABLE 2138 bool "Build a relocatable kernel" 2139 default y 2140 ---help--- 2141 This builds a kernel image that retains relocation information 2142 so it can be loaded someplace besides the default 1MB. 2143 The relocations tend to make the kernel binary about 10% larger, 2144 but are discarded at runtime. 2145 2146 One use is for the kexec on panic case where the recovery kernel 2147 must live at a different physical address than the primary 2148 kernel. 2149 2150 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2151 it has been loaded at and the compile time physical address 2152 (CONFIG_PHYSICAL_START) is used as the minimum location. 2153 2154config RANDOMIZE_BASE 2155 bool "Randomize the address of the kernel image (KASLR)" 2156 depends on RELOCATABLE 2157 default y 2158 ---help--- 2159 In support of Kernel Address Space Layout Randomization (KASLR), 2160 this randomizes the physical address at which the kernel image 2161 is decompressed and the virtual address where the kernel 2162 image is mapped, as a security feature that deters exploit 2163 attempts relying on knowledge of the location of kernel 2164 code internals. 2165 2166 On 64-bit, the kernel physical and virtual addresses are 2167 randomized separately. The physical address will be anywhere 2168 between 16MB and the top of physical memory (up to 64TB). The 2169 virtual address will be randomized from 16MB up to 1GB (9 bits 2170 of entropy). Note that this also reduces the memory space 2171 available to kernel modules from 1.5GB to 1GB. 2172 2173 On 32-bit, the kernel physical and virtual addresses are 2174 randomized together. They will be randomized from 16MB up to 2175 512MB (8 bits of entropy). 2176 2177 Entropy is generated using the RDRAND instruction if it is 2178 supported. If RDTSC is supported, its value is mixed into 2179 the entropy pool as well. If neither RDRAND nor RDTSC are 2180 supported, then entropy is read from the i8254 timer. The 2181 usable entropy is limited by the kernel being built using 2182 2GB addressing, and that PHYSICAL_ALIGN must be at a 2183 minimum of 2MB. As a result, only 10 bits of entropy are 2184 theoretically possible, but the implementations are further 2185 limited due to memory layouts. 2186 2187 If unsure, say Y. 2188 2189# Relocation on x86 needs some additional build support 2190config X86_NEED_RELOCS 2191 def_bool y 2192 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2193 2194config PHYSICAL_ALIGN 2195 hex "Alignment value to which kernel should be aligned" 2196 default "0x200000" 2197 range 0x2000 0x1000000 if X86_32 2198 range 0x200000 0x1000000 if X86_64 2199 ---help--- 2200 This value puts the alignment restrictions on physical address 2201 where kernel is loaded and run from. Kernel is compiled for an 2202 address which meets above alignment restriction. 2203 2204 If bootloader loads the kernel at a non-aligned address and 2205 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2206 address aligned to above value and run from there. 2207 2208 If bootloader loads the kernel at a non-aligned address and 2209 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2210 load address and decompress itself to the address it has been 2211 compiled for and run from there. The address for which kernel is 2212 compiled already meets above alignment restrictions. Hence the 2213 end result is that kernel runs from a physical address meeting 2214 above alignment restrictions. 2215 2216 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2217 this value must be a multiple of 0x200000. 2218 2219 Don't change this unless you know what you are doing. 2220 2221config DYNAMIC_MEMORY_LAYOUT 2222 bool 2223 ---help--- 2224 This option makes base addresses of vmalloc and vmemmap as well as 2225 __PAGE_OFFSET movable during boot. 2226 2227config RANDOMIZE_MEMORY 2228 bool "Randomize the kernel memory sections" 2229 depends on X86_64 2230 depends on RANDOMIZE_BASE 2231 select DYNAMIC_MEMORY_LAYOUT 2232 default RANDOMIZE_BASE 2233 ---help--- 2234 Randomizes the base virtual address of kernel memory sections 2235 (physical memory mapping, vmalloc & vmemmap). This security feature 2236 makes exploits relying on predictable memory locations less reliable. 2237 2238 The order of allocations remains unchanged. Entropy is generated in 2239 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2240 configuration have in average 30,000 different possible virtual 2241 addresses for each memory section. 2242 2243 If unsure, say Y. 2244 2245config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2246 hex "Physical memory mapping padding" if EXPERT 2247 depends on RANDOMIZE_MEMORY 2248 default "0xa" if MEMORY_HOTPLUG 2249 default "0x0" 2250 range 0x1 0x40 if MEMORY_HOTPLUG 2251 range 0x0 0x40 2252 ---help--- 2253 Define the padding in terabytes added to the existing physical 2254 memory size during kernel memory randomization. It is useful 2255 for memory hotplug support but reduces the entropy available for 2256 address randomization. 2257 2258 If unsure, leave at the default value. 2259 2260config HOTPLUG_CPU 2261 def_bool y 2262 depends on SMP 2263 2264config BOOTPARAM_HOTPLUG_CPU0 2265 bool "Set default setting of cpu0_hotpluggable" 2266 depends on HOTPLUG_CPU 2267 ---help--- 2268 Set whether default state of cpu0_hotpluggable is on or off. 2269 2270 Say Y here to enable CPU0 hotplug by default. If this switch 2271 is turned on, there is no need to give cpu0_hotplug kernel 2272 parameter and the CPU0 hotplug feature is enabled by default. 2273 2274 Please note: there are two known CPU0 dependencies if you want 2275 to enable the CPU0 hotplug feature either by this switch or by 2276 cpu0_hotplug kernel parameter. 2277 2278 First, resume from hibernate or suspend always starts from CPU0. 2279 So hibernate and suspend are prevented if CPU0 is offline. 2280 2281 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2282 offline if any interrupt can not migrate out of CPU0. There may 2283 be other CPU0 dependencies. 2284 2285 Please make sure the dependencies are under your control before 2286 you enable this feature. 2287 2288 Say N if you don't want to enable CPU0 hotplug feature by default. 2289 You still can enable the CPU0 hotplug feature at boot by kernel 2290 parameter cpu0_hotplug. 2291 2292config DEBUG_HOTPLUG_CPU0 2293 def_bool n 2294 prompt "Debug CPU0 hotplug" 2295 depends on HOTPLUG_CPU 2296 ---help--- 2297 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2298 soon as possible and boots up userspace with CPU0 offlined. User 2299 can online CPU0 back after boot time. 2300 2301 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2302 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2303 compilation or giving cpu0_hotplug kernel parameter at boot. 2304 2305 If unsure, say N. 2306 2307config COMPAT_VDSO 2308 def_bool n 2309 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2310 depends on COMPAT_32 2311 ---help--- 2312 Certain buggy versions of glibc will crash if they are 2313 presented with a 32-bit vDSO that is not mapped at the address 2314 indicated in its segment table. 2315 2316 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2317 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2318 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2319 the only released version with the bug, but OpenSUSE 9 2320 contains a buggy "glibc 2.3.2". 2321 2322 The symptom of the bug is that everything crashes on startup, saying: 2323 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2324 2325 Saying Y here changes the default value of the vdso32 boot 2326 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2327 This works around the glibc bug but hurts performance. 2328 2329 If unsure, say N: if you are compiling your own kernel, you 2330 are unlikely to be using a buggy version of glibc. 2331 2332choice 2333 prompt "vsyscall table for legacy applications" 2334 depends on X86_64 2335 default LEGACY_VSYSCALL_XONLY 2336 help 2337 Legacy user code that does not know how to find the vDSO expects 2338 to be able to issue three syscalls by calling fixed addresses in 2339 kernel space. Since this location is not randomized with ASLR, 2340 it can be used to assist security vulnerability exploitation. 2341 2342 This setting can be changed at boot time via the kernel command 2343 line parameter vsyscall=[emulate|xonly|none]. 2344 2345 On a system with recent enough glibc (2.14 or newer) and no 2346 static binaries, you can say None without a performance penalty 2347 to improve security. 2348 2349 If unsure, select "Emulate execution only". 2350 2351 config LEGACY_VSYSCALL_EMULATE 2352 bool "Full emulation" 2353 help 2354 The kernel traps and emulates calls into the fixed vsyscall 2355 address mapping. This makes the mapping non-executable, but 2356 it still contains readable known contents, which could be 2357 used in certain rare security vulnerability exploits. This 2358 configuration is recommended when using legacy userspace 2359 that still uses vsyscalls along with legacy binary 2360 instrumentation tools that require code to be readable. 2361 2362 An example of this type of legacy userspace is running 2363 Pin on an old binary that still uses vsyscalls. 2364 2365 config LEGACY_VSYSCALL_XONLY 2366 bool "Emulate execution only" 2367 help 2368 The kernel traps and emulates calls into the fixed vsyscall 2369 address mapping and does not allow reads. This 2370 configuration is recommended when userspace might use the 2371 legacy vsyscall area but support for legacy binary 2372 instrumentation of legacy code is not needed. It mitigates 2373 certain uses of the vsyscall area as an ASLR-bypassing 2374 buffer. 2375 2376 config LEGACY_VSYSCALL_NONE 2377 bool "None" 2378 help 2379 There will be no vsyscall mapping at all. This will 2380 eliminate any risk of ASLR bypass due to the vsyscall 2381 fixed address mapping. Attempts to use the vsyscalls 2382 will be reported to dmesg, so that either old or 2383 malicious userspace programs can be identified. 2384 2385endchoice 2386 2387config CMDLINE_BOOL 2388 bool "Built-in kernel command line" 2389 ---help--- 2390 Allow for specifying boot arguments to the kernel at 2391 build time. On some systems (e.g. embedded ones), it is 2392 necessary or convenient to provide some or all of the 2393 kernel boot arguments with the kernel itself (that is, 2394 to not rely on the boot loader to provide them.) 2395 2396 To compile command line arguments into the kernel, 2397 set this option to 'Y', then fill in the 2398 boot arguments in CONFIG_CMDLINE. 2399 2400 Systems with fully functional boot loaders (i.e. non-embedded) 2401 should leave this option set to 'N'. 2402 2403config CMDLINE 2404 string "Built-in kernel command string" 2405 depends on CMDLINE_BOOL 2406 default "" 2407 ---help--- 2408 Enter arguments here that should be compiled into the kernel 2409 image and used at boot time. If the boot loader provides a 2410 command line at boot time, it is appended to this string to 2411 form the full kernel command line, when the system boots. 2412 2413 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2414 change this behavior. 2415 2416 In most cases, the command line (whether built-in or provided 2417 by the boot loader) should specify the device for the root 2418 file system. 2419 2420config CMDLINE_OVERRIDE 2421 bool "Built-in command line overrides boot loader arguments" 2422 depends on CMDLINE_BOOL 2423 ---help--- 2424 Set this option to 'Y' to have the kernel ignore the boot loader 2425 command line, and use ONLY the built-in command line. 2426 2427 This is used to work around broken boot loaders. This should 2428 be set to 'N' under normal conditions. 2429 2430config MODIFY_LDT_SYSCALL 2431 bool "Enable the LDT (local descriptor table)" if EXPERT 2432 default y 2433 ---help--- 2434 Linux can allow user programs to install a per-process x86 2435 Local Descriptor Table (LDT) using the modify_ldt(2) system 2436 call. This is required to run 16-bit or segmented code such as 2437 DOSEMU or some Wine programs. It is also used by some very old 2438 threading libraries. 2439 2440 Enabling this feature adds a small amount of overhead to 2441 context switches and increases the low-level kernel attack 2442 surface. Disabling it removes the modify_ldt(2) system call. 2443 2444 Saying 'N' here may make sense for embedded or server kernels. 2445 2446source "kernel/livepatch/Kconfig" 2447 2448endmenu 2449 2450config ARCH_HAS_ADD_PAGES 2451 def_bool y 2452 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2453 2454config ARCH_ENABLE_MEMORY_HOTPLUG 2455 def_bool y 2456 depends on X86_64 || (X86_32 && HIGHMEM) 2457 2458config ARCH_ENABLE_MEMORY_HOTREMOVE 2459 def_bool y 2460 depends on MEMORY_HOTPLUG 2461 2462config USE_PERCPU_NUMA_NODE_ID 2463 def_bool y 2464 depends on NUMA 2465 2466config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2467 def_bool y 2468 depends on X86_64 || X86_PAE 2469 2470config ARCH_ENABLE_HUGEPAGE_MIGRATION 2471 def_bool y 2472 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2473 2474config ARCH_ENABLE_THP_MIGRATION 2475 def_bool y 2476 depends on X86_64 && TRANSPARENT_HUGEPAGE 2477 2478menu "Power management and ACPI options" 2479 2480config ARCH_HIBERNATION_HEADER 2481 def_bool y 2482 depends on HIBERNATION 2483 2484source "kernel/power/Kconfig" 2485 2486source "drivers/acpi/Kconfig" 2487 2488source "drivers/sfi/Kconfig" 2489 2490config X86_APM_BOOT 2491 def_bool y 2492 depends on APM 2493 2494menuconfig APM 2495 tristate "APM (Advanced Power Management) BIOS support" 2496 depends on X86_32 && PM_SLEEP 2497 ---help--- 2498 APM is a BIOS specification for saving power using several different 2499 techniques. This is mostly useful for battery powered laptops with 2500 APM compliant BIOSes. If you say Y here, the system time will be 2501 reset after a RESUME operation, the /proc/apm device will provide 2502 battery status information, and user-space programs will receive 2503 notification of APM "events" (e.g. battery status change). 2504 2505 If you select "Y" here, you can disable actual use of the APM 2506 BIOS by passing the "apm=off" option to the kernel at boot time. 2507 2508 Note that the APM support is almost completely disabled for 2509 machines with more than one CPU. 2510 2511 In order to use APM, you will need supporting software. For location 2512 and more information, read <file:Documentation/power/apm-acpi.rst> 2513 and the Battery Powered Linux mini-HOWTO, available from 2514 <http://www.tldp.org/docs.html#howto>. 2515 2516 This driver does not spin down disk drives (see the hdparm(8) 2517 manpage ("man 8 hdparm") for that), and it doesn't turn off 2518 VESA-compliant "green" monitors. 2519 2520 This driver does not support the TI 4000M TravelMate and the ACER 2521 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2522 desktop machines also don't have compliant BIOSes, and this driver 2523 may cause those machines to panic during the boot phase. 2524 2525 Generally, if you don't have a battery in your machine, there isn't 2526 much point in using this driver and you should say N. If you get 2527 random kernel OOPSes or reboots that don't seem to be related to 2528 anything, try disabling/enabling this option (or disabling/enabling 2529 APM in your BIOS). 2530 2531 Some other things you should try when experiencing seemingly random, 2532 "weird" problems: 2533 2534 1) make sure that you have enough swap space and that it is 2535 enabled. 2536 2) pass the "no-hlt" option to the kernel 2537 3) switch on floating point emulation in the kernel and pass 2538 the "no387" option to the kernel 2539 4) pass the "floppy=nodma" option to the kernel 2540 5) pass the "mem=4M" option to the kernel (thereby disabling 2541 all but the first 4 MB of RAM) 2542 6) make sure that the CPU is not over clocked. 2543 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2544 8) disable the cache from your BIOS settings 2545 9) install a fan for the video card or exchange video RAM 2546 10) install a better fan for the CPU 2547 11) exchange RAM chips 2548 12) exchange the motherboard. 2549 2550 To compile this driver as a module, choose M here: the 2551 module will be called apm. 2552 2553if APM 2554 2555config APM_IGNORE_USER_SUSPEND 2556 bool "Ignore USER SUSPEND" 2557 ---help--- 2558 This option will ignore USER SUSPEND requests. On machines with a 2559 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2560 series notebooks, it is necessary to say Y because of a BIOS bug. 2561 2562config APM_DO_ENABLE 2563 bool "Enable PM at boot time" 2564 ---help--- 2565 Enable APM features at boot time. From page 36 of the APM BIOS 2566 specification: "When disabled, the APM BIOS does not automatically 2567 power manage devices, enter the Standby State, enter the Suspend 2568 State, or take power saving steps in response to CPU Idle calls." 2569 This driver will make CPU Idle calls when Linux is idle (unless this 2570 feature is turned off -- see "Do CPU IDLE calls", below). This 2571 should always save battery power, but more complicated APM features 2572 will be dependent on your BIOS implementation. You may need to turn 2573 this option off if your computer hangs at boot time when using APM 2574 support, or if it beeps continuously instead of suspending. Turn 2575 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2576 T400CDT. This is off by default since most machines do fine without 2577 this feature. 2578 2579config APM_CPU_IDLE 2580 depends on CPU_IDLE 2581 bool "Make CPU Idle calls when idle" 2582 ---help--- 2583 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2584 On some machines, this can activate improved power savings, such as 2585 a slowed CPU clock rate, when the machine is idle. These idle calls 2586 are made after the idle loop has run for some length of time (e.g., 2587 333 mS). On some machines, this will cause a hang at boot time or 2588 whenever the CPU becomes idle. (On machines with more than one CPU, 2589 this option does nothing.) 2590 2591config APM_DISPLAY_BLANK 2592 bool "Enable console blanking using APM" 2593 ---help--- 2594 Enable console blanking using the APM. Some laptops can use this to 2595 turn off the LCD backlight when the screen blanker of the Linux 2596 virtual console blanks the screen. Note that this is only used by 2597 the virtual console screen blanker, and won't turn off the backlight 2598 when using the X Window system. This also doesn't have anything to 2599 do with your VESA-compliant power-saving monitor. Further, this 2600 option doesn't work for all laptops -- it might not turn off your 2601 backlight at all, or it might print a lot of errors to the console, 2602 especially if you are using gpm. 2603 2604config APM_ALLOW_INTS 2605 bool "Allow interrupts during APM BIOS calls" 2606 ---help--- 2607 Normally we disable external interrupts while we are making calls to 2608 the APM BIOS as a measure to lessen the effects of a badly behaving 2609 BIOS implementation. The BIOS should reenable interrupts if it 2610 needs to. Unfortunately, some BIOSes do not -- especially those in 2611 many of the newer IBM Thinkpads. If you experience hangs when you 2612 suspend, try setting this to Y. Otherwise, say N. 2613 2614endif # APM 2615 2616source "drivers/cpufreq/Kconfig" 2617 2618source "drivers/cpuidle/Kconfig" 2619 2620source "drivers/idle/Kconfig" 2621 2622endmenu 2623 2624 2625menu "Bus options (PCI etc.)" 2626 2627choice 2628 prompt "PCI access mode" 2629 depends on X86_32 && PCI 2630 default PCI_GOANY 2631 ---help--- 2632 On PCI systems, the BIOS can be used to detect the PCI devices and 2633 determine their configuration. However, some old PCI motherboards 2634 have BIOS bugs and may crash if this is done. Also, some embedded 2635 PCI-based systems don't have any BIOS at all. Linux can also try to 2636 detect the PCI hardware directly without using the BIOS. 2637 2638 With this option, you can specify how Linux should detect the 2639 PCI devices. If you choose "BIOS", the BIOS will be used, 2640 if you choose "Direct", the BIOS won't be used, and if you 2641 choose "MMConfig", then PCI Express MMCONFIG will be used. 2642 If you choose "Any", the kernel will try MMCONFIG, then the 2643 direct access method and falls back to the BIOS if that doesn't 2644 work. If unsure, go with the default, which is "Any". 2645 2646config PCI_GOBIOS 2647 bool "BIOS" 2648 2649config PCI_GOMMCONFIG 2650 bool "MMConfig" 2651 2652config PCI_GODIRECT 2653 bool "Direct" 2654 2655config PCI_GOOLPC 2656 bool "OLPC XO-1" 2657 depends on OLPC 2658 2659config PCI_GOANY 2660 bool "Any" 2661 2662endchoice 2663 2664config PCI_BIOS 2665 def_bool y 2666 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2667 2668# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2669config PCI_DIRECT 2670 def_bool y 2671 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2672 2673config PCI_MMCONFIG 2674 bool "Support mmconfig PCI config space access" if X86_64 2675 default y 2676 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2677 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2678 2679config PCI_OLPC 2680 def_bool y 2681 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2682 2683config PCI_XEN 2684 def_bool y 2685 depends on PCI && XEN 2686 select SWIOTLB_XEN 2687 2688config MMCONF_FAM10H 2689 def_bool y 2690 depends on X86_64 && PCI_MMCONFIG && ACPI 2691 2692config PCI_CNB20LE_QUIRK 2693 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2694 depends on PCI 2695 help 2696 Read the PCI windows out of the CNB20LE host bridge. This allows 2697 PCI hotplug to work on systems with the CNB20LE chipset which do 2698 not have ACPI. 2699 2700 There's no public spec for this chipset, and this functionality 2701 is known to be incomplete. 2702 2703 You should say N unless you know you need this. 2704 2705config ISA_BUS 2706 bool "ISA bus support on modern systems" if EXPERT 2707 help 2708 Expose ISA bus device drivers and options available for selection and 2709 configuration. Enable this option if your target machine has an ISA 2710 bus. ISA is an older system, displaced by PCI and newer bus 2711 architectures -- if your target machine is modern, it probably does 2712 not have an ISA bus. 2713 2714 If unsure, say N. 2715 2716# x86_64 have no ISA slots, but can have ISA-style DMA. 2717config ISA_DMA_API 2718 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2719 default y 2720 help 2721 Enables ISA-style DMA support for devices requiring such controllers. 2722 If unsure, say Y. 2723 2724if X86_32 2725 2726config ISA 2727 bool "ISA support" 2728 ---help--- 2729 Find out whether you have ISA slots on your motherboard. ISA is the 2730 name of a bus system, i.e. the way the CPU talks to the other stuff 2731 inside your box. Other bus systems are PCI, EISA, MicroChannel 2732 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2733 newer boards don't support it. If you have ISA, say Y, otherwise N. 2734 2735config SCx200 2736 tristate "NatSemi SCx200 support" 2737 ---help--- 2738 This provides basic support for National Semiconductor's 2739 (now AMD's) Geode processors. The driver probes for the 2740 PCI-IDs of several on-chip devices, so its a good dependency 2741 for other scx200_* drivers. 2742 2743 If compiled as a module, the driver is named scx200. 2744 2745config SCx200HR_TIMER 2746 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2747 depends on SCx200 2748 default y 2749 ---help--- 2750 This driver provides a clocksource built upon the on-chip 2751 27MHz high-resolution timer. Its also a workaround for 2752 NSC Geode SC-1100's buggy TSC, which loses time when the 2753 processor goes idle (as is done by the scheduler). The 2754 other workaround is idle=poll boot option. 2755 2756config OLPC 2757 bool "One Laptop Per Child support" 2758 depends on !X86_PAE 2759 select GPIOLIB 2760 select OF 2761 select OF_PROMTREE 2762 select IRQ_DOMAIN 2763 select OLPC_EC 2764 ---help--- 2765 Add support for detecting the unique features of the OLPC 2766 XO hardware. 2767 2768config OLPC_XO1_PM 2769 bool "OLPC XO-1 Power Management" 2770 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2771 ---help--- 2772 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2773 2774config OLPC_XO1_RTC 2775 bool "OLPC XO-1 Real Time Clock" 2776 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2777 ---help--- 2778 Add support for the XO-1 real time clock, which can be used as a 2779 programmable wakeup source. 2780 2781config OLPC_XO1_SCI 2782 bool "OLPC XO-1 SCI extras" 2783 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2784 depends on INPUT=y 2785 select POWER_SUPPLY 2786 ---help--- 2787 Add support for SCI-based features of the OLPC XO-1 laptop: 2788 - EC-driven system wakeups 2789 - Power button 2790 - Ebook switch 2791 - Lid switch 2792 - AC adapter status updates 2793 - Battery status updates 2794 2795config OLPC_XO15_SCI 2796 bool "OLPC XO-1.5 SCI extras" 2797 depends on OLPC && ACPI 2798 select POWER_SUPPLY 2799 ---help--- 2800 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2801 - EC-driven system wakeups 2802 - AC adapter status updates 2803 - Battery status updates 2804 2805config ALIX 2806 bool "PCEngines ALIX System Support (LED setup)" 2807 select GPIOLIB 2808 ---help--- 2809 This option enables system support for the PCEngines ALIX. 2810 At present this just sets up LEDs for GPIO control on 2811 ALIX2/3/6 boards. However, other system specific setup should 2812 get added here. 2813 2814 Note: You must still enable the drivers for GPIO and LED support 2815 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2816 2817 Note: You have to set alix.force=1 for boards with Award BIOS. 2818 2819config NET5501 2820 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2821 select GPIOLIB 2822 ---help--- 2823 This option enables system support for the Soekris Engineering net5501. 2824 2825config GEOS 2826 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2827 select GPIOLIB 2828 depends on DMI 2829 ---help--- 2830 This option enables system support for the Traverse Technologies GEOS. 2831 2832config TS5500 2833 bool "Technologic Systems TS-5500 platform support" 2834 depends on MELAN 2835 select CHECK_SIGNATURE 2836 select NEW_LEDS 2837 select LEDS_CLASS 2838 ---help--- 2839 This option enables system support for the Technologic Systems TS-5500. 2840 2841endif # X86_32 2842 2843config AMD_NB 2844 def_bool y 2845 depends on CPU_SUP_AMD && PCI 2846 2847config X86_SYSFB 2848 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2849 help 2850 Firmwares often provide initial graphics framebuffers so the BIOS, 2851 bootloader or kernel can show basic video-output during boot for 2852 user-guidance and debugging. Historically, x86 used the VESA BIOS 2853 Extensions and EFI-framebuffers for this, which are mostly limited 2854 to x86. 2855 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2856 framebuffers so the new generic system-framebuffer drivers can be 2857 used on x86. If the framebuffer is not compatible with the generic 2858 modes, it is advertised as fallback platform framebuffer so legacy 2859 drivers like efifb, vesafb and uvesafb can pick it up. 2860 If this option is not selected, all system framebuffers are always 2861 marked as fallback platform framebuffers as usual. 2862 2863 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2864 not be able to pick up generic system framebuffers if this option 2865 is selected. You are highly encouraged to enable simplefb as 2866 replacement if you select this option. simplefb can correctly deal 2867 with generic system framebuffers. But you should still keep vesafb 2868 and others enabled as fallback if a system framebuffer is 2869 incompatible with simplefb. 2870 2871 If unsure, say Y. 2872 2873endmenu 2874 2875 2876menu "Binary Emulations" 2877 2878config IA32_EMULATION 2879 bool "IA32 Emulation" 2880 depends on X86_64 2881 select ARCH_WANT_OLD_COMPAT_IPC 2882 select BINFMT_ELF 2883 select COMPAT_BINFMT_ELF 2884 select COMPAT_OLD_SIGACTION 2885 ---help--- 2886 Include code to run legacy 32-bit programs under a 2887 64-bit kernel. You should likely turn this on, unless you're 2888 100% sure that you don't have any 32-bit programs left. 2889 2890config IA32_AOUT 2891 tristate "IA32 a.out support" 2892 depends on IA32_EMULATION 2893 depends on BROKEN 2894 ---help--- 2895 Support old a.out binaries in the 32bit emulation. 2896 2897config X86_X32 2898 bool "x32 ABI for 64-bit mode" 2899 depends on X86_64 2900 ---help--- 2901 Include code to run binaries for the x32 native 32-bit ABI 2902 for 64-bit processors. An x32 process gets access to the 2903 full 64-bit register file and wide data path while leaving 2904 pointers at 32 bits for smaller memory footprint. 2905 2906 You will need a recent binutils (2.22 or later) with 2907 elf32_x86_64 support enabled to compile a kernel with this 2908 option set. 2909 2910config COMPAT_32 2911 def_bool y 2912 depends on IA32_EMULATION || X86_32 2913 select HAVE_UID16 2914 select OLD_SIGSUSPEND3 2915 2916config COMPAT 2917 def_bool y 2918 depends on IA32_EMULATION || X86_X32 2919 2920if COMPAT 2921config COMPAT_FOR_U64_ALIGNMENT 2922 def_bool y 2923 2924config SYSVIPC_COMPAT 2925 def_bool y 2926 depends on SYSVIPC 2927endif 2928 2929endmenu 2930 2931 2932config HAVE_ATOMIC_IOMAP 2933 def_bool y 2934 depends on X86_32 2935 2936source "drivers/firmware/Kconfig" 2937 2938source "arch/x86/kvm/Kconfig" 2939