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 34config FORCE_DYNAMIC_FTRACE 35 def_bool y 36 depends on X86_32 37 depends on FUNCTION_TRACER 38 select DYNAMIC_FTRACE 39 help 40 We keep the static function tracing (!DYNAMIC_FTRACE) around 41 in order to test the non static function tracing in the 42 generic code, as other architectures still use it. But we 43 only need to keep it around for x86_64. No need to keep it 44 for x86_32. For x86_32, force DYNAMIC_FTRACE. 45# 46# Arch settings 47# 48# ( Note that options that are marked 'if X86_64' could in principle be 49# ported to 32-bit as well. ) 50# 51config X86 52 def_bool y 53 # 54 # Note: keep this list sorted alphabetically 55 # 56 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 57 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 58 select ARCH_32BIT_OFF_T if X86_32 59 select ARCH_CLOCKSOURCE_INIT 60 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 61 select ARCH_HAS_DEBUG_VIRTUAL 62 select ARCH_HAS_DEVMEM_IS_ALLOWED 63 select ARCH_HAS_ELF_RANDOMIZE 64 select ARCH_HAS_FAST_MULTIPLIER 65 select ARCH_HAS_FILTER_PGPROT 66 select ARCH_HAS_FORTIFY_SOURCE 67 select ARCH_HAS_GCOV_PROFILE_ALL 68 select ARCH_HAS_KCOV if X86_64 69 select ARCH_HAS_MEM_ENCRYPT 70 select ARCH_HAS_MEMBARRIER_SYNC_CORE 71 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 72 select ARCH_HAS_PMEM_API if X86_64 73 select ARCH_HAS_PTE_DEVMAP if X86_64 74 select ARCH_HAS_PTE_SPECIAL 75 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 76 select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE 77 select ARCH_HAS_SET_MEMORY 78 select ARCH_HAS_SET_DIRECT_MAP 79 select ARCH_HAS_STRICT_KERNEL_RWX 80 select ARCH_HAS_STRICT_MODULE_RWX 81 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 82 select ARCH_HAS_SYSCALL_WRAPPER 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 HARDIRQS_SW_RESEND 132 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 133 select HAVE_ACPI_APEI if ACPI 134 select HAVE_ACPI_APEI_NMI if ACPI 135 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 136 select HAVE_ARCH_AUDITSYSCALL 137 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 138 select HAVE_ARCH_JUMP_LABEL 139 select HAVE_ARCH_JUMP_LABEL_RELATIVE 140 select HAVE_ARCH_KASAN if X86_64 141 select HAVE_ARCH_KASAN_VMALLOC if X86_64 142 select HAVE_ARCH_KGDB 143 select HAVE_ARCH_MMAP_RND_BITS if MMU 144 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 145 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 146 select HAVE_ARCH_PREL32_RELOCATIONS 147 select HAVE_ARCH_SECCOMP_FILTER 148 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 149 select HAVE_ARCH_STACKLEAK 150 select HAVE_ARCH_TRACEHOOK 151 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 152 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 153 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 154 select HAVE_ARCH_VMAP_STACK if X86_64 155 select HAVE_ARCH_WITHIN_STACK_FRAMES 156 select HAVE_ASM_MODVERSIONS 157 select HAVE_CMPXCHG_DOUBLE 158 select HAVE_CMPXCHG_LOCAL 159 select HAVE_CONTEXT_TRACKING if X86_64 160 select HAVE_COPY_THREAD_TLS 161 select HAVE_C_RECORDMCOUNT 162 select HAVE_DEBUG_KMEMLEAK 163 select HAVE_DMA_CONTIGUOUS 164 select HAVE_DYNAMIC_FTRACE 165 select HAVE_DYNAMIC_FTRACE_WITH_REGS 166 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 167 select HAVE_EBPF_JIT 168 select HAVE_EFFICIENT_UNALIGNED_ACCESS 169 select HAVE_EISA 170 select HAVE_EXIT_THREAD 171 select HAVE_FAST_GUP 172 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 173 select HAVE_FTRACE_MCOUNT_RECORD 174 select HAVE_FUNCTION_GRAPH_TRACER 175 select HAVE_FUNCTION_TRACER 176 select HAVE_GCC_PLUGINS 177 select HAVE_HW_BREAKPOINT 178 select HAVE_IDE 179 select HAVE_IOREMAP_PROT 180 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 181 select HAVE_IRQ_TIME_ACCOUNTING 182 select HAVE_KERNEL_BZIP2 183 select HAVE_KERNEL_GZIP 184 select HAVE_KERNEL_LZ4 185 select HAVE_KERNEL_LZMA 186 select HAVE_KERNEL_LZO 187 select HAVE_KERNEL_XZ 188 select HAVE_KPROBES 189 select HAVE_KPROBES_ON_FTRACE 190 select HAVE_FUNCTION_ERROR_INJECTION 191 select HAVE_KRETPROBES 192 select HAVE_KVM 193 select HAVE_LIVEPATCH if X86_64 194 select HAVE_MEMBLOCK_NODE_MAP 195 select HAVE_MIXED_BREAKPOINTS_REGS 196 select HAVE_MOD_ARCH_SPECIFIC 197 select HAVE_MOVE_PMD 198 select HAVE_NMI 199 select HAVE_OPROFILE 200 select HAVE_OPTPROBES 201 select HAVE_PCSPKR_PLATFORM 202 select HAVE_PERF_EVENTS 203 select HAVE_PERF_EVENTS_NMI 204 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 205 select HAVE_PCI 206 select HAVE_PERF_REGS 207 select HAVE_PERF_USER_STACK_DUMP 208 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 209 select HAVE_REGS_AND_STACK_ACCESS_API 210 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 211 select HAVE_FUNCTION_ARG_ACCESS_API 212 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 213 select HAVE_STACK_VALIDATION if X86_64 214 select HAVE_RSEQ 215 select HAVE_SYSCALL_TRACEPOINTS 216 select HAVE_UNSTABLE_SCHED_CLOCK 217 select HAVE_USER_RETURN_NOTIFIER 218 select HAVE_GENERIC_VDSO 219 select HOTPLUG_SMT if SMP 220 select IRQ_FORCED_THREADING 221 select NEED_SG_DMA_LENGTH 222 select PCI_DOMAINS if PCI 223 select PCI_LOCKLESS_CONFIG if PCI 224 select PERF_EVENTS 225 select RTC_LIB 226 select RTC_MC146818_LIB 227 select SPARSE_IRQ 228 select SRCU 229 select SYSCTL_EXCEPTION_TRACE 230 select THREAD_INFO_IN_TASK 231 select USER_STACKTRACE_SUPPORT 232 select VIRT_TO_BUS 233 select X86_FEATURE_NAMES if PROC_FS 234 select PROC_PID_ARCH_STATUS if PROC_FS 235 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 236 237config INSTRUCTION_DECODER 238 def_bool y 239 depends on KPROBES || PERF_EVENTS || UPROBES 240 241config OUTPUT_FORMAT 242 string 243 default "elf32-i386" if X86_32 244 default "elf64-x86-64" if X86_64 245 246config LOCKDEP_SUPPORT 247 def_bool y 248 249config STACKTRACE_SUPPORT 250 def_bool y 251 252config MMU 253 def_bool y 254 255config ARCH_MMAP_RND_BITS_MIN 256 default 28 if 64BIT 257 default 8 258 259config ARCH_MMAP_RND_BITS_MAX 260 default 32 if 64BIT 261 default 16 262 263config ARCH_MMAP_RND_COMPAT_BITS_MIN 264 default 8 265 266config ARCH_MMAP_RND_COMPAT_BITS_MAX 267 default 16 268 269config SBUS 270 bool 271 272config GENERIC_ISA_DMA 273 def_bool y 274 depends on ISA_DMA_API 275 276config GENERIC_BUG 277 def_bool y 278 depends on BUG 279 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 280 281config GENERIC_BUG_RELATIVE_POINTERS 282 bool 283 284config ARCH_MAY_HAVE_PC_FDC 285 def_bool y 286 depends on ISA_DMA_API 287 288config GENERIC_CALIBRATE_DELAY 289 def_bool y 290 291config ARCH_HAS_CPU_RELAX 292 def_bool y 293 294config ARCH_HAS_CACHE_LINE_SIZE 295 def_bool y 296 297config ARCH_HAS_FILTER_PGPROT 298 def_bool y 299 300config HAVE_SETUP_PER_CPU_AREA 301 def_bool y 302 303config NEED_PER_CPU_EMBED_FIRST_CHUNK 304 def_bool y 305 306config NEED_PER_CPU_PAGE_FIRST_CHUNK 307 def_bool y 308 309config ARCH_HIBERNATION_POSSIBLE 310 def_bool y 311 312config ARCH_SUSPEND_POSSIBLE 313 def_bool y 314 315config ARCH_WANT_GENERAL_HUGETLB 316 def_bool y 317 318config ZONE_DMA32 319 def_bool y if X86_64 320 321config AUDIT_ARCH 322 def_bool y if X86_64 323 324config ARCH_SUPPORTS_DEBUG_PAGEALLOC 325 def_bool y 326 327config KASAN_SHADOW_OFFSET 328 hex 329 depends on KASAN 330 default 0xdffffc0000000000 331 332config HAVE_INTEL_TXT 333 def_bool y 334 depends on INTEL_IOMMU && ACPI 335 336config X86_32_SMP 337 def_bool y 338 depends on X86_32 && SMP 339 340config X86_64_SMP 341 def_bool y 342 depends on X86_64 && SMP 343 344config X86_32_LAZY_GS 345 def_bool y 346 depends on X86_32 && !STACKPROTECTOR 347 348config ARCH_SUPPORTS_UPROBES 349 def_bool y 350 351config FIX_EARLYCON_MEM 352 def_bool y 353 354config DYNAMIC_PHYSICAL_MASK 355 bool 356 357config PGTABLE_LEVELS 358 int 359 default 5 if X86_5LEVEL 360 default 4 if X86_64 361 default 3 if X86_PAE 362 default 2 363 364config CC_HAS_SANE_STACKPROTECTOR 365 bool 366 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 367 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 368 help 369 We have to make sure stack protector is unconditionally disabled if 370 the compiler produces broken code. 371 372menu "Processor type and features" 373 374config ZONE_DMA 375 bool "DMA memory allocation support" if EXPERT 376 default y 377 help 378 DMA memory allocation support allows devices with less than 32-bit 379 addressing to allocate within the first 16MB of address space. 380 Disable if no such devices will be used. 381 382 If unsure, say Y. 383 384config SMP 385 bool "Symmetric multi-processing support" 386 ---help--- 387 This enables support for systems with more than one CPU. If you have 388 a system with only one CPU, say N. If you have a system with more 389 than one CPU, say Y. 390 391 If you say N here, the kernel will run on uni- and multiprocessor 392 machines, but will use only one CPU of a multiprocessor machine. If 393 you say Y here, the kernel will run on many, but not all, 394 uniprocessor machines. On a uniprocessor machine, the kernel 395 will run faster if you say N here. 396 397 Note that if you say Y here and choose architecture "586" or 398 "Pentium" under "Processor family", the kernel will not work on 486 399 architectures. Similarly, multiprocessor kernels for the "PPro" 400 architecture may not work on all Pentium based boards. 401 402 People using multiprocessor machines who say Y here should also say 403 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 404 Management" code will be disabled if you say Y here. 405 406 See also <file:Documentation/x86/i386/IO-APIC.rst>, 407 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 408 <http://www.tldp.org/docs.html#howto>. 409 410 If you don't know what to do here, say N. 411 412config X86_FEATURE_NAMES 413 bool "Processor feature human-readable names" if EMBEDDED 414 default y 415 ---help--- 416 This option compiles in a table of x86 feature bits and corresponding 417 names. This is required to support /proc/cpuinfo and a few kernel 418 messages. You can disable this to save space, at the expense of 419 making those few kernel messages show numeric feature bits instead. 420 421 If in doubt, say Y. 422 423config X86_X2APIC 424 bool "Support x2apic" 425 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 426 ---help--- 427 This enables x2apic support on CPUs that have this feature. 428 429 This allows 32-bit apic IDs (so it can support very large systems), 430 and accesses the local apic via MSRs not via mmio. 431 432 If you don't know what to do here, say N. 433 434config X86_MPPARSE 435 bool "Enable MPS table" if ACPI || SFI 436 default y 437 depends on X86_LOCAL_APIC 438 ---help--- 439 For old smp systems that do not have proper acpi support. Newer systems 440 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 441 442config GOLDFISH 443 def_bool y 444 depends on X86_GOLDFISH 445 446config RETPOLINE 447 bool "Avoid speculative indirect branches in kernel" 448 default y 449 select STACK_VALIDATION if HAVE_STACK_VALIDATION 450 help 451 Compile kernel with the retpoline compiler options to guard against 452 kernel-to-user data leaks by avoiding speculative indirect 453 branches. Requires a compiler with -mindirect-branch=thunk-extern 454 support for full protection. The kernel may run slower. 455 456config X86_CPU_RESCTRL 457 bool "x86 CPU resource control support" 458 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 459 select KERNFS 460 select PROC_CPU_RESCTRL if PROC_FS 461 help 462 Enable x86 CPU resource control support. 463 464 Provide support for the allocation and monitoring of system resources 465 usage by the CPU. 466 467 Intel calls this Intel Resource Director Technology 468 (Intel(R) RDT). More information about RDT can be found in the 469 Intel x86 Architecture Software Developer Manual. 470 471 AMD calls this AMD Platform Quality of Service (AMD QoS). 472 More information about AMD QoS can be found in the AMD64 Technology 473 Platform Quality of Service Extensions manual. 474 475 Say N if unsure. 476 477if X86_32 478config X86_BIGSMP 479 bool "Support for big SMP systems with more than 8 CPUs" 480 depends on SMP 481 ---help--- 482 This option is needed for the systems that have more than 8 CPUs. 483 484config X86_EXTENDED_PLATFORM 485 bool "Support for extended (non-PC) x86 platforms" 486 default y 487 ---help--- 488 If you disable this option then the kernel will only support 489 standard PC platforms. (which covers the vast majority of 490 systems out there.) 491 492 If you enable this option then you'll be able to select support 493 for the following (non-PC) 32 bit x86 platforms: 494 Goldfish (Android emulator) 495 AMD Elan 496 RDC R-321x SoC 497 SGI 320/540 (Visual Workstation) 498 STA2X11-based (e.g. Northville) 499 Moorestown MID devices 500 501 If you have one of these systems, or if you want to build a 502 generic distribution kernel, say Y here - otherwise say N. 503endif 504 505if X86_64 506config X86_EXTENDED_PLATFORM 507 bool "Support for extended (non-PC) x86 platforms" 508 default y 509 ---help--- 510 If you disable this option then the kernel will only support 511 standard PC platforms. (which covers the vast majority of 512 systems out there.) 513 514 If you enable this option then you'll be able to select support 515 for the following (non-PC) 64 bit x86 platforms: 516 Numascale NumaChip 517 ScaleMP vSMP 518 SGI Ultraviolet 519 520 If you have one of these systems, or if you want to build a 521 generic distribution kernel, say Y here - otherwise say N. 522endif 523# This is an alphabetically sorted list of 64 bit extended platforms 524# Please maintain the alphabetic order if and when there are additions 525config X86_NUMACHIP 526 bool "Numascale NumaChip" 527 depends on X86_64 528 depends on X86_EXTENDED_PLATFORM 529 depends on NUMA 530 depends on SMP 531 depends on X86_X2APIC 532 depends on PCI_MMCONFIG 533 ---help--- 534 Adds support for Numascale NumaChip large-SMP systems. Needed to 535 enable more than ~168 cores. 536 If you don't have one of these, you should say N here. 537 538config X86_VSMP 539 bool "ScaleMP vSMP" 540 select HYPERVISOR_GUEST 541 select PARAVIRT 542 depends on X86_64 && PCI 543 depends on X86_EXTENDED_PLATFORM 544 depends on SMP 545 ---help--- 546 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 547 supposed to run on these EM64T-based machines. Only choose this option 548 if you have one of these machines. 549 550config X86_UV 551 bool "SGI Ultraviolet" 552 depends on X86_64 553 depends on X86_EXTENDED_PLATFORM 554 depends on NUMA 555 depends on EFI 556 depends on X86_X2APIC 557 depends on PCI 558 ---help--- 559 This option is needed in order to support SGI Ultraviolet systems. 560 If you don't have one of these, you should say N here. 561 562# Following is an alphabetically sorted list of 32 bit extended platforms 563# Please maintain the alphabetic order if and when there are additions 564 565config X86_GOLDFISH 566 bool "Goldfish (Virtual Platform)" 567 depends on X86_EXTENDED_PLATFORM 568 ---help--- 569 Enable support for the Goldfish virtual platform used primarily 570 for Android development. Unless you are building for the Android 571 Goldfish emulator say N here. 572 573config X86_INTEL_CE 574 bool "CE4100 TV platform" 575 depends on PCI 576 depends on PCI_GODIRECT 577 depends on X86_IO_APIC 578 depends on X86_32 579 depends on X86_EXTENDED_PLATFORM 580 select X86_REBOOTFIXUPS 581 select OF 582 select OF_EARLY_FLATTREE 583 ---help--- 584 Select for the Intel CE media processor (CE4100) SOC. 585 This option compiles in support for the CE4100 SOC for settop 586 boxes and media devices. 587 588config X86_INTEL_MID 589 bool "Intel MID platform support" 590 depends on X86_EXTENDED_PLATFORM 591 depends on X86_PLATFORM_DEVICES 592 depends on PCI 593 depends on X86_64 || (PCI_GOANY && X86_32) 594 depends on X86_IO_APIC 595 select SFI 596 select I2C 597 select DW_APB_TIMER 598 select APB_TIMER 599 select INTEL_SCU_IPC 600 select MFD_INTEL_MSIC 601 ---help--- 602 Select to build a kernel capable of supporting Intel MID (Mobile 603 Internet Device) platform systems which do not have the PCI legacy 604 interfaces. If you are building for a PC class system say N here. 605 606 Intel MID platforms are based on an Intel processor and chipset which 607 consume less power than most of the x86 derivatives. 608 609config X86_INTEL_QUARK 610 bool "Intel Quark platform support" 611 depends on X86_32 612 depends on X86_EXTENDED_PLATFORM 613 depends on X86_PLATFORM_DEVICES 614 depends on X86_TSC 615 depends on PCI 616 depends on PCI_GOANY 617 depends on X86_IO_APIC 618 select IOSF_MBI 619 select INTEL_IMR 620 select COMMON_CLK 621 ---help--- 622 Select to include support for Quark X1000 SoC. 623 Say Y here if you have a Quark based system such as the Arduino 624 compatible Intel Galileo. 625 626config X86_INTEL_LPSS 627 bool "Intel Low Power Subsystem Support" 628 depends on X86 && ACPI && PCI 629 select COMMON_CLK 630 select PINCTRL 631 select IOSF_MBI 632 ---help--- 633 Select to build support for Intel Low Power Subsystem such as 634 found on Intel Lynxpoint PCH. Selecting this option enables 635 things like clock tree (common clock framework) and pincontrol 636 which are needed by the LPSS peripheral drivers. 637 638config X86_AMD_PLATFORM_DEVICE 639 bool "AMD ACPI2Platform devices support" 640 depends on ACPI 641 select COMMON_CLK 642 select PINCTRL 643 ---help--- 644 Select to interpret AMD specific ACPI device to platform device 645 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 646 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 647 implemented under PINCTRL subsystem. 648 649config IOSF_MBI 650 tristate "Intel SoC IOSF Sideband support for SoC platforms" 651 depends on PCI 652 ---help--- 653 This option enables sideband register access support for Intel SoC 654 platforms. On these platforms the IOSF sideband is used in lieu of 655 MSR's for some register accesses, mostly but not limited to thermal 656 and power. Drivers may query the availability of this device to 657 determine if they need the sideband in order to work on these 658 platforms. The sideband is available on the following SoC products. 659 This list is not meant to be exclusive. 660 - BayTrail 661 - Braswell 662 - Quark 663 664 You should say Y if you are running a kernel on one of these SoC's. 665 666config IOSF_MBI_DEBUG 667 bool "Enable IOSF sideband access through debugfs" 668 depends on IOSF_MBI && DEBUG_FS 669 ---help--- 670 Select this option to expose the IOSF sideband access registers (MCR, 671 MDR, MCRX) through debugfs to write and read register information from 672 different units on the SoC. This is most useful for obtaining device 673 state information for debug and analysis. As this is a general access 674 mechanism, users of this option would have specific knowledge of the 675 device they want to access. 676 677 If you don't require the option or are in doubt, say N. 678 679config X86_RDC321X 680 bool "RDC R-321x SoC" 681 depends on X86_32 682 depends on X86_EXTENDED_PLATFORM 683 select M486 684 select X86_REBOOTFIXUPS 685 ---help--- 686 This option is needed for RDC R-321x system-on-chip, also known 687 as R-8610-(G). 688 If you don't have one of these chips, you should say N here. 689 690config X86_32_NON_STANDARD 691 bool "Support non-standard 32-bit SMP architectures" 692 depends on X86_32 && SMP 693 depends on X86_EXTENDED_PLATFORM 694 ---help--- 695 This option compiles in the bigsmp and STA2X11 default 696 subarchitectures. It is intended for a generic binary 697 kernel. If you select them all, kernel will probe it one by 698 one and will fallback to default. 699 700# Alphabetically sorted list of Non standard 32 bit platforms 701 702config X86_SUPPORTS_MEMORY_FAILURE 703 def_bool y 704 # MCE code calls memory_failure(): 705 depends on X86_MCE 706 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 707 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 708 depends on X86_64 || !SPARSEMEM 709 select ARCH_SUPPORTS_MEMORY_FAILURE 710 711config STA2X11 712 bool "STA2X11 Companion Chip Support" 713 depends on X86_32_NON_STANDARD && PCI 714 select SWIOTLB 715 select MFD_STA2X11 716 select GPIOLIB 717 ---help--- 718 This adds support for boards based on the STA2X11 IO-Hub, 719 a.k.a. "ConneXt". The chip is used in place of the standard 720 PC chipset, so all "standard" peripherals are missing. If this 721 option is selected the kernel will still be able to boot on 722 standard PC machines. 723 724config X86_32_IRIS 725 tristate "Eurobraille/Iris poweroff module" 726 depends on X86_32 727 ---help--- 728 The Iris machines from EuroBraille do not have APM or ACPI support 729 to shut themselves down properly. A special I/O sequence is 730 needed to do so, which is what this module does at 731 kernel shutdown. 732 733 This is only for Iris machines from EuroBraille. 734 735 If unused, say N. 736 737config SCHED_OMIT_FRAME_POINTER 738 def_bool y 739 prompt "Single-depth WCHAN output" 740 depends on X86 741 ---help--- 742 Calculate simpler /proc/<PID>/wchan values. If this option 743 is disabled then wchan values will recurse back to the 744 caller function. This provides more accurate wchan values, 745 at the expense of slightly more scheduling overhead. 746 747 If in doubt, say "Y". 748 749menuconfig HYPERVISOR_GUEST 750 bool "Linux guest support" 751 ---help--- 752 Say Y here to enable options for running Linux under various hyper- 753 visors. This option enables basic hypervisor detection and platform 754 setup. 755 756 If you say N, all options in this submenu will be skipped and 757 disabled, and Linux guest support won't be built in. 758 759if HYPERVISOR_GUEST 760 761config PARAVIRT 762 bool "Enable paravirtualization code" 763 ---help--- 764 This changes the kernel so it can modify itself when it is run 765 under a hypervisor, potentially improving performance significantly 766 over full virtualization. However, when run without a hypervisor 767 the kernel is theoretically slower and slightly larger. 768 769config PARAVIRT_XXL 770 bool 771 772config PARAVIRT_DEBUG 773 bool "paravirt-ops debugging" 774 depends on PARAVIRT && DEBUG_KERNEL 775 ---help--- 776 Enable to debug paravirt_ops internals. Specifically, BUG if 777 a paravirt_op is missing when it is called. 778 779config PARAVIRT_SPINLOCKS 780 bool "Paravirtualization layer for spinlocks" 781 depends on PARAVIRT && SMP 782 ---help--- 783 Paravirtualized spinlocks allow a pvops backend to replace the 784 spinlock implementation with something virtualization-friendly 785 (for example, block the virtual CPU rather than spinning). 786 787 It has a minimal impact on native kernels and gives a nice performance 788 benefit on paravirtualized KVM / Xen kernels. 789 790 If you are unsure how to answer this question, answer Y. 791 792config X86_HV_CALLBACK_VECTOR 793 def_bool n 794 795source "arch/x86/xen/Kconfig" 796 797config KVM_GUEST 798 bool "KVM Guest support (including kvmclock)" 799 depends on PARAVIRT 800 select PARAVIRT_CLOCK 801 select ARCH_CPUIDLE_HALTPOLL 802 default y 803 ---help--- 804 This option enables various optimizations for running under the KVM 805 hypervisor. It includes a paravirtualized clock, so that instead 806 of relying on a PIT (or probably other) emulation by the 807 underlying device model, the host provides the guest with 808 timing infrastructure such as time of day, and system time 809 810config ARCH_CPUIDLE_HALTPOLL 811 def_bool n 812 prompt "Disable host haltpoll when loading haltpoll driver" 813 help 814 If virtualized under KVM, disable host haltpoll. 815 816config PVH 817 bool "Support for running PVH guests" 818 ---help--- 819 This option enables the PVH entry point for guest virtual machines 820 as specified in the x86/HVM direct boot ABI. 821 822config KVM_DEBUG_FS 823 bool "Enable debug information for KVM Guests in debugfs" 824 depends on KVM_GUEST && DEBUG_FS 825 ---help--- 826 This option enables collection of various statistics for KVM guest. 827 Statistics are displayed in debugfs filesystem. Enabling this option 828 may incur significant overhead. 829 830config PARAVIRT_TIME_ACCOUNTING 831 bool "Paravirtual steal time accounting" 832 depends on PARAVIRT 833 ---help--- 834 Select this option to enable fine granularity task steal time 835 accounting. Time spent executing other tasks in parallel with 836 the current vCPU is discounted from the vCPU power. To account for 837 that, there can be a small performance impact. 838 839 If in doubt, say N here. 840 841config PARAVIRT_CLOCK 842 bool 843 844config JAILHOUSE_GUEST 845 bool "Jailhouse non-root cell support" 846 depends on X86_64 && PCI 847 select X86_PM_TIMER 848 ---help--- 849 This option allows to run Linux as guest in a Jailhouse non-root 850 cell. You can leave this option disabled if you only want to start 851 Jailhouse and run Linux afterwards in the root cell. 852 853config ACRN_GUEST 854 bool "ACRN Guest support" 855 depends on X86_64 856 select X86_HV_CALLBACK_VECTOR 857 help 858 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 859 a flexible, lightweight reference open-source hypervisor, built with 860 real-time and safety-criticality in mind. It is built for embedded 861 IOT with small footprint and real-time features. More details can be 862 found in https://projectacrn.org/. 863 864endif #HYPERVISOR_GUEST 865 866source "arch/x86/Kconfig.cpu" 867 868config HPET_TIMER 869 def_bool X86_64 870 prompt "HPET Timer Support" if X86_32 871 ---help--- 872 Use the IA-PC HPET (High Precision Event Timer) to manage 873 time in preference to the PIT and RTC, if a HPET is 874 present. 875 HPET is the next generation timer replacing legacy 8254s. 876 The HPET provides a stable time base on SMP 877 systems, unlike the TSC, but it is more expensive to access, 878 as it is off-chip. The interface used is documented 879 in the HPET spec, revision 1. 880 881 You can safely choose Y here. However, HPET will only be 882 activated if the platform and the BIOS support this feature. 883 Otherwise the 8254 will be used for timing services. 884 885 Choose N to continue using the legacy 8254 timer. 886 887config HPET_EMULATE_RTC 888 def_bool y 889 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 890 891config APB_TIMER 892 def_bool y if X86_INTEL_MID 893 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 894 select DW_APB_TIMER 895 depends on X86_INTEL_MID && SFI 896 help 897 APB timer is the replacement for 8254, HPET on X86 MID platforms. 898 The APBT provides a stable time base on SMP 899 systems, unlike the TSC, but it is more expensive to access, 900 as it is off-chip. APB timers are always running regardless of CPU 901 C states, they are used as per CPU clockevent device when possible. 902 903# Mark as expert because too many people got it wrong. 904# The code disables itself when not needed. 905config DMI 906 default y 907 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 908 bool "Enable DMI scanning" if EXPERT 909 ---help--- 910 Enabled scanning of DMI to identify machine quirks. Say Y 911 here unless you have verified that your setup is not 912 affected by entries in the DMI blacklist. Required by PNP 913 BIOS code. 914 915config GART_IOMMU 916 bool "Old AMD GART IOMMU support" 917 select IOMMU_HELPER 918 select SWIOTLB 919 depends on X86_64 && PCI && AMD_NB 920 ---help--- 921 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 922 GART based hardware IOMMUs. 923 924 The GART supports full DMA access for devices with 32-bit access 925 limitations, on systems with more than 3 GB. This is usually needed 926 for USB, sound, many IDE/SATA chipsets and some other devices. 927 928 Newer systems typically have a modern AMD IOMMU, supported via 929 the CONFIG_AMD_IOMMU=y config option. 930 931 In normal configurations this driver is only active when needed: 932 there's more than 3 GB of memory and the system contains a 933 32-bit limited device. 934 935 If unsure, say Y. 936 937config MAXSMP 938 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 939 depends on X86_64 && SMP && DEBUG_KERNEL 940 select CPUMASK_OFFSTACK 941 ---help--- 942 Enable maximum number of CPUS and NUMA Nodes for this architecture. 943 If unsure, say N. 944 945# 946# The maximum number of CPUs supported: 947# 948# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 949# and which can be configured interactively in the 950# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 951# 952# The ranges are different on 32-bit and 64-bit kernels, depending on 953# hardware capabilities and scalability features of the kernel. 954# 955# ( If MAXSMP is enabled we just use the highest possible value and disable 956# interactive configuration. ) 957# 958 959config NR_CPUS_RANGE_BEGIN 960 int 961 default NR_CPUS_RANGE_END if MAXSMP 962 default 1 if !SMP 963 default 2 964 965config NR_CPUS_RANGE_END 966 int 967 depends on X86_32 968 default 64 if SMP && X86_BIGSMP 969 default 8 if SMP && !X86_BIGSMP 970 default 1 if !SMP 971 972config NR_CPUS_RANGE_END 973 int 974 depends on X86_64 975 default 8192 if SMP && CPUMASK_OFFSTACK 976 default 512 if SMP && !CPUMASK_OFFSTACK 977 default 1 if !SMP 978 979config NR_CPUS_DEFAULT 980 int 981 depends on X86_32 982 default 32 if X86_BIGSMP 983 default 8 if SMP 984 default 1 if !SMP 985 986config NR_CPUS_DEFAULT 987 int 988 depends on X86_64 989 default 8192 if MAXSMP 990 default 64 if SMP 991 default 1 if !SMP 992 993config NR_CPUS 994 int "Maximum number of CPUs" if SMP && !MAXSMP 995 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 996 default NR_CPUS_DEFAULT 997 ---help--- 998 This allows you to specify the maximum number of CPUs which this 999 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1000 supported value is 8192, otherwise the maximum value is 512. The 1001 minimum value which makes sense is 2. 1002 1003 This is purely to save memory: each supported CPU adds about 8KB 1004 to the kernel image. 1005 1006config SCHED_SMT 1007 def_bool y if SMP 1008 1009config SCHED_MC 1010 def_bool y 1011 prompt "Multi-core scheduler support" 1012 depends on SMP 1013 ---help--- 1014 Multi-core scheduler support improves the CPU scheduler's decision 1015 making when dealing with multi-core CPU chips at a cost of slightly 1016 increased overhead in some places. If unsure say N here. 1017 1018config SCHED_MC_PRIO 1019 bool "CPU core priorities scheduler support" 1020 depends on SCHED_MC && CPU_SUP_INTEL 1021 select X86_INTEL_PSTATE 1022 select CPU_FREQ 1023 default y 1024 ---help--- 1025 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1026 core ordering determined at manufacturing time, which allows 1027 certain cores to reach higher turbo frequencies (when running 1028 single threaded workloads) than others. 1029 1030 Enabling this kernel feature teaches the scheduler about 1031 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1032 scheduler's CPU selection logic accordingly, so that higher 1033 overall system performance can be achieved. 1034 1035 This feature will have no effect on CPUs without this feature. 1036 1037 If unsure say Y here. 1038 1039config UP_LATE_INIT 1040 def_bool y 1041 depends on !SMP && X86_LOCAL_APIC 1042 1043config X86_UP_APIC 1044 bool "Local APIC support on uniprocessors" if !PCI_MSI 1045 default PCI_MSI 1046 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1047 ---help--- 1048 A local APIC (Advanced Programmable Interrupt Controller) is an 1049 integrated interrupt controller in the CPU. If you have a single-CPU 1050 system which has a processor with a local APIC, you can say Y here to 1051 enable and use it. If you say Y here even though your machine doesn't 1052 have a local APIC, then the kernel will still run with no slowdown at 1053 all. The local APIC supports CPU-generated self-interrupts (timer, 1054 performance counters), and the NMI watchdog which detects hard 1055 lockups. 1056 1057config X86_UP_IOAPIC 1058 bool "IO-APIC support on uniprocessors" 1059 depends on X86_UP_APIC 1060 ---help--- 1061 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1062 SMP-capable replacement for PC-style interrupt controllers. Most 1063 SMP systems and many recent uniprocessor systems have one. 1064 1065 If you have a single-CPU system with an IO-APIC, you can say Y here 1066 to use it. If you say Y here even though your machine doesn't have 1067 an IO-APIC, then the kernel will still run with no slowdown at all. 1068 1069config X86_LOCAL_APIC 1070 def_bool y 1071 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1072 select IRQ_DOMAIN_HIERARCHY 1073 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1074 1075config X86_IO_APIC 1076 def_bool y 1077 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1078 1079config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1080 bool "Reroute for broken boot IRQs" 1081 depends on X86_IO_APIC 1082 ---help--- 1083 This option enables a workaround that fixes a source of 1084 spurious interrupts. This is recommended when threaded 1085 interrupt handling is used on systems where the generation of 1086 superfluous "boot interrupts" cannot be disabled. 1087 1088 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1089 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1090 kernel does during interrupt handling). On chipsets where this 1091 boot IRQ generation cannot be disabled, this workaround keeps 1092 the original IRQ line masked so that only the equivalent "boot 1093 IRQ" is delivered to the CPUs. The workaround also tells the 1094 kernel to set up the IRQ handler on the boot IRQ line. In this 1095 way only one interrupt is delivered to the kernel. Otherwise 1096 the spurious second interrupt may cause the kernel to bring 1097 down (vital) interrupt lines. 1098 1099 Only affects "broken" chipsets. Interrupt sharing may be 1100 increased on these systems. 1101 1102config X86_MCE 1103 bool "Machine Check / overheating reporting" 1104 select GENERIC_ALLOCATOR 1105 default y 1106 ---help--- 1107 Machine Check support allows the processor to notify the 1108 kernel if it detects a problem (e.g. overheating, data corruption). 1109 The action the kernel takes depends on the severity of the problem, 1110 ranging from warning messages to halting the machine. 1111 1112config X86_MCELOG_LEGACY 1113 bool "Support for deprecated /dev/mcelog character device" 1114 depends on X86_MCE 1115 ---help--- 1116 Enable support for /dev/mcelog which is needed by the old mcelog 1117 userspace logging daemon. Consider switching to the new generation 1118 rasdaemon solution. 1119 1120config X86_MCE_INTEL 1121 def_bool y 1122 prompt "Intel MCE features" 1123 depends on X86_MCE && X86_LOCAL_APIC 1124 ---help--- 1125 Additional support for intel specific MCE features such as 1126 the thermal monitor. 1127 1128config X86_MCE_AMD 1129 def_bool y 1130 prompt "AMD MCE features" 1131 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1132 ---help--- 1133 Additional support for AMD specific MCE features such as 1134 the DRAM Error Threshold. 1135 1136config X86_ANCIENT_MCE 1137 bool "Support for old Pentium 5 / WinChip machine checks" 1138 depends on X86_32 && X86_MCE 1139 ---help--- 1140 Include support for machine check handling on old Pentium 5 or WinChip 1141 systems. These typically need to be enabled explicitly on the command 1142 line. 1143 1144config X86_MCE_THRESHOLD 1145 depends on X86_MCE_AMD || X86_MCE_INTEL 1146 def_bool y 1147 1148config X86_MCE_INJECT 1149 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1150 tristate "Machine check injector support" 1151 ---help--- 1152 Provide support for injecting machine checks for testing purposes. 1153 If you don't know what a machine check is and you don't do kernel 1154 QA it is safe to say n. 1155 1156config X86_THERMAL_VECTOR 1157 def_bool y 1158 depends on X86_MCE_INTEL 1159 1160source "arch/x86/events/Kconfig" 1161 1162config X86_LEGACY_VM86 1163 bool "Legacy VM86 support" 1164 depends on X86_32 1165 ---help--- 1166 This option allows user programs to put the CPU into V8086 1167 mode, which is an 80286-era approximation of 16-bit real mode. 1168 1169 Some very old versions of X and/or vbetool require this option 1170 for user mode setting. Similarly, DOSEMU will use it if 1171 available to accelerate real mode DOS programs. However, any 1172 recent version of DOSEMU, X, or vbetool should be fully 1173 functional even without kernel VM86 support, as they will all 1174 fall back to software emulation. Nevertheless, if you are using 1175 a 16-bit DOS program where 16-bit performance matters, vm86 1176 mode might be faster than emulation and you might want to 1177 enable this option. 1178 1179 Note that any app that works on a 64-bit kernel is unlikely to 1180 need this option, as 64-bit kernels don't, and can't, support 1181 V8086 mode. This option is also unrelated to 16-bit protected 1182 mode and is not needed to run most 16-bit programs under Wine. 1183 1184 Enabling this option increases the complexity of the kernel 1185 and slows down exception handling a tiny bit. 1186 1187 If unsure, say N here. 1188 1189config VM86 1190 bool 1191 default X86_LEGACY_VM86 1192 1193config X86_16BIT 1194 bool "Enable support for 16-bit segments" if EXPERT 1195 default y 1196 depends on MODIFY_LDT_SYSCALL 1197 ---help--- 1198 This option is required by programs like Wine to run 16-bit 1199 protected mode legacy code on x86 processors. Disabling 1200 this option saves about 300 bytes on i386, or around 6K text 1201 plus 16K runtime memory on x86-64, 1202 1203config X86_ESPFIX32 1204 def_bool y 1205 depends on X86_16BIT && X86_32 1206 1207config X86_ESPFIX64 1208 def_bool y 1209 depends on X86_16BIT && X86_64 1210 1211config X86_VSYSCALL_EMULATION 1212 bool "Enable vsyscall emulation" if EXPERT 1213 default y 1214 depends on X86_64 1215 ---help--- 1216 This enables emulation of the legacy vsyscall page. Disabling 1217 it is roughly equivalent to booting with vsyscall=none, except 1218 that it will also disable the helpful warning if a program 1219 tries to use a vsyscall. With this option set to N, offending 1220 programs will just segfault, citing addresses of the form 1221 0xffffffffff600?00. 1222 1223 This option is required by many programs built before 2013, and 1224 care should be used even with newer programs if set to N. 1225 1226 Disabling this option saves about 7K of kernel size and 1227 possibly 4K of additional runtime pagetable memory. 1228 1229config X86_IOPL_IOPERM 1230 bool "IOPERM and IOPL Emulation" 1231 default y 1232 ---help--- 1233 This enables the ioperm() and iopl() syscalls which are necessary 1234 for legacy applications. 1235 1236 Legacy IOPL support is an overbroad mechanism which allows user 1237 space aside of accessing all 65536 I/O ports also to disable 1238 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1239 capabilities and permission from potentially active security 1240 modules. 1241 1242 The emulation restricts the functionality of the syscall to 1243 only allowing the full range I/O port access, but prevents the 1244 ability to disable interrupts from user space which would be 1245 granted if the hardware IOPL mechanism would be used. 1246 1247config TOSHIBA 1248 tristate "Toshiba Laptop support" 1249 depends on X86_32 1250 ---help--- 1251 This adds a driver to safely access the System Management Mode of 1252 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1253 not work on models with a Phoenix BIOS. The System Management Mode 1254 is used to set the BIOS and power saving options on Toshiba portables. 1255 1256 For information on utilities to make use of this driver see the 1257 Toshiba Linux utilities web site at: 1258 <http://www.buzzard.org.uk/toshiba/>. 1259 1260 Say Y if you intend to run this kernel on a Toshiba portable. 1261 Say N otherwise. 1262 1263config I8K 1264 tristate "Dell i8k legacy laptop support" 1265 select HWMON 1266 select SENSORS_DELL_SMM 1267 ---help--- 1268 This option enables legacy /proc/i8k userspace interface in hwmon 1269 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1270 temperature and allows controlling fan speeds of Dell laptops via 1271 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1272 it reports also power and hotkey status. For fan speed control is 1273 needed userspace package i8kutils. 1274 1275 Say Y if you intend to run this kernel on old Dell laptops or want to 1276 use userspace package i8kutils. 1277 Say N otherwise. 1278 1279config X86_REBOOTFIXUPS 1280 bool "Enable X86 board specific fixups for reboot" 1281 depends on X86_32 1282 ---help--- 1283 This enables chipset and/or board specific fixups to be done 1284 in order to get reboot to work correctly. This is only needed on 1285 some combinations of hardware and BIOS. The symptom, for which 1286 this config is intended, is when reboot ends with a stalled/hung 1287 system. 1288 1289 Currently, the only fixup is for the Geode machines using 1290 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1291 1292 Say Y if you want to enable the fixup. Currently, it's safe to 1293 enable this option even if you don't need it. 1294 Say N otherwise. 1295 1296config MICROCODE 1297 bool "CPU microcode loading support" 1298 default y 1299 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1300 select FW_LOADER 1301 ---help--- 1302 If you say Y here, you will be able to update the microcode on 1303 Intel and AMD processors. The Intel support is for the IA32 family, 1304 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1305 AMD support is for families 0x10 and later. You will obviously need 1306 the actual microcode binary data itself which is not shipped with 1307 the Linux kernel. 1308 1309 The preferred method to load microcode from a detached initrd is described 1310 in Documentation/x86/microcode.rst. For that you need to enable 1311 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1312 initrd for microcode blobs. 1313 1314 In addition, you can build the microcode into the kernel. For that you 1315 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1316 config option. 1317 1318config MICROCODE_INTEL 1319 bool "Intel microcode loading support" 1320 depends on MICROCODE 1321 default MICROCODE 1322 select FW_LOADER 1323 ---help--- 1324 This options enables microcode patch loading support for Intel 1325 processors. 1326 1327 For the current Intel microcode data package go to 1328 <https://downloadcenter.intel.com> and search for 1329 'Linux Processor Microcode Data File'. 1330 1331config MICROCODE_AMD 1332 bool "AMD microcode loading support" 1333 depends on MICROCODE 1334 select FW_LOADER 1335 ---help--- 1336 If you select this option, microcode patch loading support for AMD 1337 processors will be enabled. 1338 1339config MICROCODE_OLD_INTERFACE 1340 bool "Ancient loading interface (DEPRECATED)" 1341 default n 1342 depends on MICROCODE 1343 ---help--- 1344 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1345 which was used by userspace tools like iucode_tool and microcode.ctl. 1346 It is inadequate because it runs too late to be able to properly 1347 load microcode on a machine and it needs special tools. Instead, you 1348 should've switched to the early loading method with the initrd or 1349 builtin microcode by now: Documentation/x86/microcode.rst 1350 1351config X86_MSR 1352 tristate "/dev/cpu/*/msr - Model-specific register support" 1353 ---help--- 1354 This device gives privileged processes access to the x86 1355 Model-Specific Registers (MSRs). It is a character device with 1356 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1357 MSR accesses are directed to a specific CPU on multi-processor 1358 systems. 1359 1360config X86_CPUID 1361 tristate "/dev/cpu/*/cpuid - CPU information support" 1362 ---help--- 1363 This device gives processes access to the x86 CPUID instruction to 1364 be executed on a specific processor. It is a character device 1365 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1366 /dev/cpu/31/cpuid. 1367 1368choice 1369 prompt "High Memory Support" 1370 default HIGHMEM4G 1371 depends on X86_32 1372 1373config NOHIGHMEM 1374 bool "off" 1375 ---help--- 1376 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1377 However, the address space of 32-bit x86 processors is only 4 1378 Gigabytes large. That means that, if you have a large amount of 1379 physical memory, not all of it can be "permanently mapped" by the 1380 kernel. The physical memory that's not permanently mapped is called 1381 "high memory". 1382 1383 If you are compiling a kernel which will never run on a machine with 1384 more than 1 Gigabyte total physical RAM, answer "off" here (default 1385 choice and suitable for most users). This will result in a "3GB/1GB" 1386 split: 3GB are mapped so that each process sees a 3GB virtual memory 1387 space and the remaining part of the 4GB virtual memory space is used 1388 by the kernel to permanently map as much physical memory as 1389 possible. 1390 1391 If the machine has between 1 and 4 Gigabytes physical RAM, then 1392 answer "4GB" here. 1393 1394 If more than 4 Gigabytes is used then answer "64GB" here. This 1395 selection turns Intel PAE (Physical Address Extension) mode on. 1396 PAE implements 3-level paging on IA32 processors. PAE is fully 1397 supported by Linux, PAE mode is implemented on all recent Intel 1398 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1399 then the kernel will not boot on CPUs that don't support PAE! 1400 1401 The actual amount of total physical memory will either be 1402 auto detected or can be forced by using a kernel command line option 1403 such as "mem=256M". (Try "man bootparam" or see the documentation of 1404 your boot loader (lilo or loadlin) about how to pass options to the 1405 kernel at boot time.) 1406 1407 If unsure, say "off". 1408 1409config HIGHMEM4G 1410 bool "4GB" 1411 ---help--- 1412 Select this if you have a 32-bit processor and between 1 and 4 1413 gigabytes of physical RAM. 1414 1415config HIGHMEM64G 1416 bool "64GB" 1417 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1418 select X86_PAE 1419 ---help--- 1420 Select this if you have a 32-bit processor and more than 4 1421 gigabytes of physical RAM. 1422 1423endchoice 1424 1425choice 1426 prompt "Memory split" if EXPERT 1427 default VMSPLIT_3G 1428 depends on X86_32 1429 ---help--- 1430 Select the desired split between kernel and user memory. 1431 1432 If the address range available to the kernel is less than the 1433 physical memory installed, the remaining memory will be available 1434 as "high memory". Accessing high memory is a little more costly 1435 than low memory, as it needs to be mapped into the kernel first. 1436 Note that increasing the kernel address space limits the range 1437 available to user programs, making the address space there 1438 tighter. Selecting anything other than the default 3G/1G split 1439 will also likely make your kernel incompatible with binary-only 1440 kernel modules. 1441 1442 If you are not absolutely sure what you are doing, leave this 1443 option alone! 1444 1445 config VMSPLIT_3G 1446 bool "3G/1G user/kernel split" 1447 config VMSPLIT_3G_OPT 1448 depends on !X86_PAE 1449 bool "3G/1G user/kernel split (for full 1G low memory)" 1450 config VMSPLIT_2G 1451 bool "2G/2G user/kernel split" 1452 config VMSPLIT_2G_OPT 1453 depends on !X86_PAE 1454 bool "2G/2G user/kernel split (for full 2G low memory)" 1455 config VMSPLIT_1G 1456 bool "1G/3G user/kernel split" 1457endchoice 1458 1459config PAGE_OFFSET 1460 hex 1461 default 0xB0000000 if VMSPLIT_3G_OPT 1462 default 0x80000000 if VMSPLIT_2G 1463 default 0x78000000 if VMSPLIT_2G_OPT 1464 default 0x40000000 if VMSPLIT_1G 1465 default 0xC0000000 1466 depends on X86_32 1467 1468config HIGHMEM 1469 def_bool y 1470 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1471 1472config X86_PAE 1473 bool "PAE (Physical Address Extension) Support" 1474 depends on X86_32 && !HIGHMEM4G 1475 select PHYS_ADDR_T_64BIT 1476 select SWIOTLB 1477 ---help--- 1478 PAE is required for NX support, and furthermore enables 1479 larger swapspace support for non-overcommit purposes. It 1480 has the cost of more pagetable lookup overhead, and also 1481 consumes more pagetable space per process. 1482 1483config X86_5LEVEL 1484 bool "Enable 5-level page tables support" 1485 default y 1486 select DYNAMIC_MEMORY_LAYOUT 1487 select SPARSEMEM_VMEMMAP 1488 depends on X86_64 1489 ---help--- 1490 5-level paging enables access to larger address space: 1491 upto 128 PiB of virtual address space and 4 PiB of 1492 physical address space. 1493 1494 It will be supported by future Intel CPUs. 1495 1496 A kernel with the option enabled can be booted on machines that 1497 support 4- or 5-level paging. 1498 1499 See Documentation/x86/x86_64/5level-paging.rst for more 1500 information. 1501 1502 Say N if unsure. 1503 1504config X86_DIRECT_GBPAGES 1505 def_bool y 1506 depends on X86_64 1507 ---help--- 1508 Certain kernel features effectively disable kernel 1509 linear 1 GB mappings (even if the CPU otherwise 1510 supports them), so don't confuse the user by printing 1511 that we have them enabled. 1512 1513config X86_CPA_STATISTICS 1514 bool "Enable statistic for Change Page Attribute" 1515 depends on DEBUG_FS 1516 ---help--- 1517 Expose statistics about the Change Page Attribute mechanism, which 1518 helps to determine the effectiveness of preserving large and huge 1519 page mappings when mapping protections are changed. 1520 1521config AMD_MEM_ENCRYPT 1522 bool "AMD Secure Memory Encryption (SME) support" 1523 depends on X86_64 && CPU_SUP_AMD 1524 select DYNAMIC_PHYSICAL_MASK 1525 select ARCH_USE_MEMREMAP_PROT 1526 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1527 ---help--- 1528 Say yes to enable support for the encryption of system memory. 1529 This requires an AMD processor that supports Secure Memory 1530 Encryption (SME). 1531 1532config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1533 bool "Activate AMD Secure Memory Encryption (SME) by default" 1534 default y 1535 depends on AMD_MEM_ENCRYPT 1536 ---help--- 1537 Say yes to have system memory encrypted by default if running on 1538 an AMD processor that supports Secure Memory Encryption (SME). 1539 1540 If set to Y, then the encryption of system memory can be 1541 deactivated with the mem_encrypt=off command line option. 1542 1543 If set to N, then the encryption of system memory can be 1544 activated with the mem_encrypt=on command line option. 1545 1546# Common NUMA Features 1547config NUMA 1548 bool "NUMA Memory Allocation and Scheduler Support" 1549 depends on SMP 1550 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1551 default y if X86_BIGSMP 1552 ---help--- 1553 Enable NUMA (Non-Uniform Memory Access) support. 1554 1555 The kernel will try to allocate memory used by a CPU on the 1556 local memory controller of the CPU and add some more 1557 NUMA awareness to the kernel. 1558 1559 For 64-bit this is recommended if the system is Intel Core i7 1560 (or later), AMD Opteron, or EM64T NUMA. 1561 1562 For 32-bit this is only needed if you boot a 32-bit 1563 kernel on a 64-bit NUMA platform. 1564 1565 Otherwise, you should say N. 1566 1567config AMD_NUMA 1568 def_bool y 1569 prompt "Old style AMD Opteron NUMA detection" 1570 depends on X86_64 && NUMA && PCI 1571 ---help--- 1572 Enable AMD NUMA node topology detection. You should say Y here if 1573 you have a multi processor AMD system. This uses an old method to 1574 read the NUMA configuration directly from the builtin Northbridge 1575 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1576 which also takes priority if both are compiled in. 1577 1578config X86_64_ACPI_NUMA 1579 def_bool y 1580 prompt "ACPI NUMA detection" 1581 depends on X86_64 && NUMA && ACPI && PCI 1582 select ACPI_NUMA 1583 ---help--- 1584 Enable ACPI SRAT based node topology detection. 1585 1586# Some NUMA nodes have memory ranges that span 1587# other nodes. Even though a pfn is valid and 1588# between a node's start and end pfns, it may not 1589# reside on that node. See memmap_init_zone() 1590# for details. 1591config NODES_SPAN_OTHER_NODES 1592 def_bool y 1593 depends on X86_64_ACPI_NUMA 1594 1595config NUMA_EMU 1596 bool "NUMA emulation" 1597 depends on NUMA 1598 ---help--- 1599 Enable NUMA emulation. A flat machine will be split 1600 into virtual nodes when booted with "numa=fake=N", where N is the 1601 number of nodes. This is only useful for debugging. 1602 1603config NODES_SHIFT 1604 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1605 range 1 10 1606 default "10" if MAXSMP 1607 default "6" if X86_64 1608 default "3" 1609 depends on NEED_MULTIPLE_NODES 1610 ---help--- 1611 Specify the maximum number of NUMA Nodes available on the target 1612 system. Increases memory reserved to accommodate various tables. 1613 1614config ARCH_HAVE_MEMORY_PRESENT 1615 def_bool y 1616 depends on X86_32 && DISCONTIGMEM 1617 1618config ARCH_FLATMEM_ENABLE 1619 def_bool y 1620 depends on X86_32 && !NUMA 1621 1622config ARCH_DISCONTIGMEM_ENABLE 1623 def_bool n 1624 depends on NUMA && X86_32 1625 depends on BROKEN 1626 1627config ARCH_SPARSEMEM_ENABLE 1628 def_bool y 1629 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1630 select SPARSEMEM_STATIC if X86_32 1631 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1632 1633config ARCH_SPARSEMEM_DEFAULT 1634 def_bool X86_64 || (NUMA && X86_32) 1635 1636config ARCH_SELECT_MEMORY_MODEL 1637 def_bool y 1638 depends on ARCH_SPARSEMEM_ENABLE 1639 1640config ARCH_MEMORY_PROBE 1641 bool "Enable sysfs memory/probe interface" 1642 depends on X86_64 && MEMORY_HOTPLUG 1643 help 1644 This option enables a sysfs memory/probe interface for testing. 1645 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1646 If you are unsure how to answer this question, answer N. 1647 1648config ARCH_PROC_KCORE_TEXT 1649 def_bool y 1650 depends on X86_64 && PROC_KCORE 1651 1652config ILLEGAL_POINTER_VALUE 1653 hex 1654 default 0 if X86_32 1655 default 0xdead000000000000 if X86_64 1656 1657config X86_PMEM_LEGACY_DEVICE 1658 bool 1659 1660config X86_PMEM_LEGACY 1661 tristate "Support non-standard NVDIMMs and ADR protected memory" 1662 depends on PHYS_ADDR_T_64BIT 1663 depends on BLK_DEV 1664 select X86_PMEM_LEGACY_DEVICE 1665 select NUMA_KEEP_MEMINFO if NUMA 1666 select LIBNVDIMM 1667 help 1668 Treat memory marked using the non-standard e820 type of 12 as used 1669 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1670 The kernel will offer these regions to the 'pmem' driver so 1671 they can be used for persistent storage. 1672 1673 Say Y if unsure. 1674 1675config HIGHPTE 1676 bool "Allocate 3rd-level pagetables from highmem" 1677 depends on HIGHMEM 1678 ---help--- 1679 The VM uses one page table entry for each page of physical memory. 1680 For systems with a lot of RAM, this can be wasteful of precious 1681 low memory. Setting this option will put user-space page table 1682 entries in high memory. 1683 1684config X86_CHECK_BIOS_CORRUPTION 1685 bool "Check for low memory corruption" 1686 ---help--- 1687 Periodically check for memory corruption in low memory, which 1688 is suspected to be caused by BIOS. Even when enabled in the 1689 configuration, it is disabled at runtime. Enable it by 1690 setting "memory_corruption_check=1" on the kernel command 1691 line. By default it scans the low 64k of memory every 60 1692 seconds; see the memory_corruption_check_size and 1693 memory_corruption_check_period parameters in 1694 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1695 1696 When enabled with the default parameters, this option has 1697 almost no overhead, as it reserves a relatively small amount 1698 of memory and scans it infrequently. It both detects corruption 1699 and prevents it from affecting the running system. 1700 1701 It is, however, intended as a diagnostic tool; if repeatable 1702 BIOS-originated corruption always affects the same memory, 1703 you can use memmap= to prevent the kernel from using that 1704 memory. 1705 1706config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1707 bool "Set the default setting of memory_corruption_check" 1708 depends on X86_CHECK_BIOS_CORRUPTION 1709 default y 1710 ---help--- 1711 Set whether the default state of memory_corruption_check is 1712 on or off. 1713 1714config X86_RESERVE_LOW 1715 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1716 default 64 1717 range 4 640 1718 ---help--- 1719 Specify the amount of low memory to reserve for the BIOS. 1720 1721 The first page contains BIOS data structures that the kernel 1722 must not use, so that page must always be reserved. 1723 1724 By default we reserve the first 64K of physical RAM, as a 1725 number of BIOSes are known to corrupt that memory range 1726 during events such as suspend/resume or monitor cable 1727 insertion, so it must not be used by the kernel. 1728 1729 You can set this to 4 if you are absolutely sure that you 1730 trust the BIOS to get all its memory reservations and usages 1731 right. If you know your BIOS have problems beyond the 1732 default 64K area, you can set this to 640 to avoid using the 1733 entire low memory range. 1734 1735 If you have doubts about the BIOS (e.g. suspend/resume does 1736 not work or there's kernel crashes after certain hardware 1737 hotplug events) then you might want to enable 1738 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1739 typical corruption patterns. 1740 1741 Leave this to the default value of 64 if you are unsure. 1742 1743config MATH_EMULATION 1744 bool 1745 depends on MODIFY_LDT_SYSCALL 1746 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1747 ---help--- 1748 Linux can emulate a math coprocessor (used for floating point 1749 operations) if you don't have one. 486DX and Pentium processors have 1750 a math coprocessor built in, 486SX and 386 do not, unless you added 1751 a 487DX or 387, respectively. (The messages during boot time can 1752 give you some hints here ["man dmesg"].) Everyone needs either a 1753 coprocessor or this emulation. 1754 1755 If you don't have a math coprocessor, you need to say Y here; if you 1756 say Y here even though you have a coprocessor, the coprocessor will 1757 be used nevertheless. (This behavior can be changed with the kernel 1758 command line option "no387", which comes handy if your coprocessor 1759 is broken. Try "man bootparam" or see the documentation of your boot 1760 loader (lilo or loadlin) about how to pass options to the kernel at 1761 boot time.) This means that it is a good idea to say Y here if you 1762 intend to use this kernel on different machines. 1763 1764 More information about the internals of the Linux math coprocessor 1765 emulation can be found in <file:arch/x86/math-emu/README>. 1766 1767 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1768 kernel, it won't hurt. 1769 1770config MTRR 1771 def_bool y 1772 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1773 ---help--- 1774 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1775 the Memory Type Range Registers (MTRRs) may be used to control 1776 processor access to memory ranges. This is most useful if you have 1777 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1778 allows bus write transfers to be combined into a larger transfer 1779 before bursting over the PCI/AGP bus. This can increase performance 1780 of image write operations 2.5 times or more. Saying Y here creates a 1781 /proc/mtrr file which may be used to manipulate your processor's 1782 MTRRs. Typically the X server should use this. 1783 1784 This code has a reasonably generic interface so that similar 1785 control registers on other processors can be easily supported 1786 as well: 1787 1788 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1789 Registers (ARRs) which provide a similar functionality to MTRRs. For 1790 these, the ARRs are used to emulate the MTRRs. 1791 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1792 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1793 write-combining. All of these processors are supported by this code 1794 and it makes sense to say Y here if you have one of them. 1795 1796 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1797 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1798 can lead to all sorts of problems, so it's good to say Y here. 1799 1800 You can safely say Y even if your machine doesn't have MTRRs, you'll 1801 just add about 9 KB to your kernel. 1802 1803 See <file:Documentation/x86/mtrr.rst> for more information. 1804 1805config MTRR_SANITIZER 1806 def_bool y 1807 prompt "MTRR cleanup support" 1808 depends on MTRR 1809 ---help--- 1810 Convert MTRR layout from continuous to discrete, so X drivers can 1811 add writeback entries. 1812 1813 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1814 The largest mtrr entry size for a continuous block can be set with 1815 mtrr_chunk_size. 1816 1817 If unsure, say Y. 1818 1819config MTRR_SANITIZER_ENABLE_DEFAULT 1820 int "MTRR cleanup enable value (0-1)" 1821 range 0 1 1822 default "0" 1823 depends on MTRR_SANITIZER 1824 ---help--- 1825 Enable mtrr cleanup default value 1826 1827config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1828 int "MTRR cleanup spare reg num (0-7)" 1829 range 0 7 1830 default "1" 1831 depends on MTRR_SANITIZER 1832 ---help--- 1833 mtrr cleanup spare entries default, it can be changed via 1834 mtrr_spare_reg_nr=N on the kernel command line. 1835 1836config X86_PAT 1837 def_bool y 1838 prompt "x86 PAT support" if EXPERT 1839 depends on MTRR 1840 ---help--- 1841 Use PAT attributes to setup page level cache control. 1842 1843 PATs are the modern equivalents of MTRRs and are much more 1844 flexible than MTRRs. 1845 1846 Say N here if you see bootup problems (boot crash, boot hang, 1847 spontaneous reboots) or a non-working video driver. 1848 1849 If unsure, say Y. 1850 1851config ARCH_USES_PG_UNCACHED 1852 def_bool y 1853 depends on X86_PAT 1854 1855config ARCH_RANDOM 1856 def_bool y 1857 prompt "x86 architectural random number generator" if EXPERT 1858 ---help--- 1859 Enable the x86 architectural RDRAND instruction 1860 (Intel Bull Mountain technology) to generate random numbers. 1861 If supported, this is a high bandwidth, cryptographically 1862 secure hardware random number generator. 1863 1864config X86_SMAP 1865 def_bool y 1866 prompt "Supervisor Mode Access Prevention" if EXPERT 1867 ---help--- 1868 Supervisor Mode Access Prevention (SMAP) is a security 1869 feature in newer Intel processors. There is a small 1870 performance cost if this enabled and turned on; there is 1871 also a small increase in the kernel size if this is enabled. 1872 1873 If unsure, say Y. 1874 1875config X86_UMIP 1876 def_bool y 1877 prompt "User Mode Instruction Prevention" if EXPERT 1878 ---help--- 1879 User Mode Instruction Prevention (UMIP) is a security feature in 1880 some x86 processors. If enabled, a general protection fault is 1881 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1882 executed in user mode. These instructions unnecessarily expose 1883 information about the hardware state. 1884 1885 The vast majority of applications do not use these instructions. 1886 For the very few that do, software emulation is provided in 1887 specific cases in protected and virtual-8086 modes. Emulated 1888 results are dummy. 1889 1890config X86_INTEL_MEMORY_PROTECTION_KEYS 1891 prompt "Intel Memory Protection Keys" 1892 def_bool y 1893 # Note: only available in 64-bit mode 1894 depends on CPU_SUP_INTEL && X86_64 1895 select ARCH_USES_HIGH_VMA_FLAGS 1896 select ARCH_HAS_PKEYS 1897 ---help--- 1898 Memory Protection Keys provides a mechanism for enforcing 1899 page-based protections, but without requiring modification of the 1900 page tables when an application changes protection domains. 1901 1902 For details, see Documentation/core-api/protection-keys.rst 1903 1904 If unsure, say y. 1905 1906choice 1907 prompt "TSX enable mode" 1908 depends on CPU_SUP_INTEL 1909 default X86_INTEL_TSX_MODE_OFF 1910 help 1911 Intel's TSX (Transactional Synchronization Extensions) feature 1912 allows to optimize locking protocols through lock elision which 1913 can lead to a noticeable performance boost. 1914 1915 On the other hand it has been shown that TSX can be exploited 1916 to form side channel attacks (e.g. TAA) and chances are there 1917 will be more of those attacks discovered in the future. 1918 1919 Therefore TSX is not enabled by default (aka tsx=off). An admin 1920 might override this decision by tsx=on the command line parameter. 1921 Even with TSX enabled, the kernel will attempt to enable the best 1922 possible TAA mitigation setting depending on the microcode available 1923 for the particular machine. 1924 1925 This option allows to set the default tsx mode between tsx=on, =off 1926 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1927 details. 1928 1929 Say off if not sure, auto if TSX is in use but it should be used on safe 1930 platforms or on if TSX is in use and the security aspect of tsx is not 1931 relevant. 1932 1933config X86_INTEL_TSX_MODE_OFF 1934 bool "off" 1935 help 1936 TSX is disabled if possible - equals to tsx=off command line parameter. 1937 1938config X86_INTEL_TSX_MODE_ON 1939 bool "on" 1940 help 1941 TSX is always enabled on TSX capable HW - equals the tsx=on command 1942 line parameter. 1943 1944config X86_INTEL_TSX_MODE_AUTO 1945 bool "auto" 1946 help 1947 TSX is enabled on TSX capable HW that is believed to be safe against 1948 side channel attacks- equals the tsx=auto command line parameter. 1949endchoice 1950 1951config EFI 1952 bool "EFI runtime service support" 1953 depends on ACPI 1954 select UCS2_STRING 1955 select EFI_RUNTIME_WRAPPERS 1956 ---help--- 1957 This enables the kernel to use EFI runtime services that are 1958 available (such as the EFI variable services). 1959 1960 This option is only useful on systems that have EFI firmware. 1961 In addition, you should use the latest ELILO loader available 1962 at <http://elilo.sourceforge.net> in order to take advantage 1963 of EFI runtime services. However, even with this option, the 1964 resultant kernel should continue to boot on existing non-EFI 1965 platforms. 1966 1967config EFI_STUB 1968 bool "EFI stub support" 1969 depends on EFI && !X86_USE_3DNOW 1970 depends on $(cc-option,-mabi=ms) || X86_32 1971 select RELOCATABLE 1972 ---help--- 1973 This kernel feature allows a bzImage to be loaded directly 1974 by EFI firmware without the use of a bootloader. 1975 1976 See Documentation/admin-guide/efi-stub.rst for more information. 1977 1978config EFI_MIXED 1979 bool "EFI mixed-mode support" 1980 depends on EFI_STUB && X86_64 1981 ---help--- 1982 Enabling this feature allows a 64-bit kernel to be booted 1983 on a 32-bit firmware, provided that your CPU supports 64-bit 1984 mode. 1985 1986 Note that it is not possible to boot a mixed-mode enabled 1987 kernel via the EFI boot stub - a bootloader that supports 1988 the EFI handover protocol must be used. 1989 1990 If unsure, say N. 1991 1992config SECCOMP 1993 def_bool y 1994 prompt "Enable seccomp to safely compute untrusted bytecode" 1995 ---help--- 1996 This kernel feature is useful for number crunching applications 1997 that may need to compute untrusted bytecode during their 1998 execution. By using pipes or other transports made available to 1999 the process as file descriptors supporting the read/write 2000 syscalls, it's possible to isolate those applications in 2001 their own address space using seccomp. Once seccomp is 2002 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 2003 and the task is only allowed to execute a few safe syscalls 2004 defined by each seccomp mode. 2005 2006 If unsure, say Y. Only embedded should say N here. 2007 2008source "kernel/Kconfig.hz" 2009 2010config KEXEC 2011 bool "kexec system call" 2012 select KEXEC_CORE 2013 ---help--- 2014 kexec is a system call that implements the ability to shutdown your 2015 current kernel, and to start another kernel. It is like a reboot 2016 but it is independent of the system firmware. And like a reboot 2017 you can start any kernel with it, not just Linux. 2018 2019 The name comes from the similarity to the exec system call. 2020 2021 It is an ongoing process to be certain the hardware in a machine 2022 is properly shutdown, so do not be surprised if this code does not 2023 initially work for you. As of this writing the exact hardware 2024 interface is strongly in flux, so no good recommendation can be 2025 made. 2026 2027config KEXEC_FILE 2028 bool "kexec file based system call" 2029 select KEXEC_CORE 2030 select BUILD_BIN2C 2031 depends on X86_64 2032 depends on CRYPTO=y 2033 depends on CRYPTO_SHA256=y 2034 ---help--- 2035 This is new version of kexec system call. This system call is 2036 file based and takes file descriptors as system call argument 2037 for kernel and initramfs as opposed to list of segments as 2038 accepted by previous system call. 2039 2040config ARCH_HAS_KEXEC_PURGATORY 2041 def_bool KEXEC_FILE 2042 2043config KEXEC_SIG 2044 bool "Verify kernel signature during kexec_file_load() syscall" 2045 depends on KEXEC_FILE 2046 ---help--- 2047 2048 This option makes the kexec_file_load() syscall check for a valid 2049 signature of the kernel image. The image can still be loaded without 2050 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2051 there's a signature that we can check, then it must be valid. 2052 2053 In addition to this option, you need to enable signature 2054 verification for the corresponding kernel image type being 2055 loaded in order for this to work. 2056 2057config KEXEC_SIG_FORCE 2058 bool "Require a valid signature in kexec_file_load() syscall" 2059 depends on KEXEC_SIG 2060 ---help--- 2061 This option makes kernel signature verification mandatory for 2062 the kexec_file_load() syscall. 2063 2064config KEXEC_BZIMAGE_VERIFY_SIG 2065 bool "Enable bzImage signature verification support" 2066 depends on KEXEC_SIG 2067 depends on SIGNED_PE_FILE_VERIFICATION 2068 select SYSTEM_TRUSTED_KEYRING 2069 ---help--- 2070 Enable bzImage signature verification support. 2071 2072config CRASH_DUMP 2073 bool "kernel crash dumps" 2074 depends on X86_64 || (X86_32 && HIGHMEM) 2075 ---help--- 2076 Generate crash dump after being started by kexec. 2077 This should be normally only set in special crash dump kernels 2078 which are loaded in the main kernel with kexec-tools into 2079 a specially reserved region and then later executed after 2080 a crash by kdump/kexec. The crash dump kernel must be compiled 2081 to a memory address not used by the main kernel or BIOS using 2082 PHYSICAL_START, or it must be built as a relocatable image 2083 (CONFIG_RELOCATABLE=y). 2084 For more details see Documentation/admin-guide/kdump/kdump.rst 2085 2086config KEXEC_JUMP 2087 bool "kexec jump" 2088 depends on KEXEC && HIBERNATION 2089 ---help--- 2090 Jump between original kernel and kexeced kernel and invoke 2091 code in physical address mode via KEXEC 2092 2093config PHYSICAL_START 2094 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2095 default "0x1000000" 2096 ---help--- 2097 This gives the physical address where the kernel is loaded. 2098 2099 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2100 bzImage will decompress itself to above physical address and 2101 run from there. Otherwise, bzImage will run from the address where 2102 it has been loaded by the boot loader and will ignore above physical 2103 address. 2104 2105 In normal kdump cases one does not have to set/change this option 2106 as now bzImage can be compiled as a completely relocatable image 2107 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2108 address. This option is mainly useful for the folks who don't want 2109 to use a bzImage for capturing the crash dump and want to use a 2110 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2111 to be specifically compiled to run from a specific memory area 2112 (normally a reserved region) and this option comes handy. 2113 2114 So if you are using bzImage for capturing the crash dump, 2115 leave the value here unchanged to 0x1000000 and set 2116 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2117 for capturing the crash dump change this value to start of 2118 the reserved region. In other words, it can be set based on 2119 the "X" value as specified in the "crashkernel=YM@XM" 2120 command line boot parameter passed to the panic-ed 2121 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2122 for more details about crash dumps. 2123 2124 Usage of bzImage for capturing the crash dump is recommended as 2125 one does not have to build two kernels. Same kernel can be used 2126 as production kernel and capture kernel. Above option should have 2127 gone away after relocatable bzImage support is introduced. But it 2128 is present because there are users out there who continue to use 2129 vmlinux for dump capture. This option should go away down the 2130 line. 2131 2132 Don't change this unless you know what you are doing. 2133 2134config RELOCATABLE 2135 bool "Build a relocatable kernel" 2136 default y 2137 ---help--- 2138 This builds a kernel image that retains relocation information 2139 so it can be loaded someplace besides the default 1MB. 2140 The relocations tend to make the kernel binary about 10% larger, 2141 but are discarded at runtime. 2142 2143 One use is for the kexec on panic case where the recovery kernel 2144 must live at a different physical address than the primary 2145 kernel. 2146 2147 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2148 it has been loaded at and the compile time physical address 2149 (CONFIG_PHYSICAL_START) is used as the minimum location. 2150 2151config RANDOMIZE_BASE 2152 bool "Randomize the address of the kernel image (KASLR)" 2153 depends on RELOCATABLE 2154 default y 2155 ---help--- 2156 In support of Kernel Address Space Layout Randomization (KASLR), 2157 this randomizes the physical address at which the kernel image 2158 is decompressed and the virtual address where the kernel 2159 image is mapped, as a security feature that deters exploit 2160 attempts relying on knowledge of the location of kernel 2161 code internals. 2162 2163 On 64-bit, the kernel physical and virtual addresses are 2164 randomized separately. The physical address will be anywhere 2165 between 16MB and the top of physical memory (up to 64TB). The 2166 virtual address will be randomized from 16MB up to 1GB (9 bits 2167 of entropy). Note that this also reduces the memory space 2168 available to kernel modules from 1.5GB to 1GB. 2169 2170 On 32-bit, the kernel physical and virtual addresses are 2171 randomized together. They will be randomized from 16MB up to 2172 512MB (8 bits of entropy). 2173 2174 Entropy is generated using the RDRAND instruction if it is 2175 supported. If RDTSC is supported, its value is mixed into 2176 the entropy pool as well. If neither RDRAND nor RDTSC are 2177 supported, then entropy is read from the i8254 timer. The 2178 usable entropy is limited by the kernel being built using 2179 2GB addressing, and that PHYSICAL_ALIGN must be at a 2180 minimum of 2MB. As a result, only 10 bits of entropy are 2181 theoretically possible, but the implementations are further 2182 limited due to memory layouts. 2183 2184 If unsure, say Y. 2185 2186# Relocation on x86 needs some additional build support 2187config X86_NEED_RELOCS 2188 def_bool y 2189 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2190 2191config PHYSICAL_ALIGN 2192 hex "Alignment value to which kernel should be aligned" 2193 default "0x200000" 2194 range 0x2000 0x1000000 if X86_32 2195 range 0x200000 0x1000000 if X86_64 2196 ---help--- 2197 This value puts the alignment restrictions on physical address 2198 where kernel is loaded and run from. Kernel is compiled for an 2199 address which meets above alignment restriction. 2200 2201 If bootloader loads the kernel at a non-aligned address and 2202 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2203 address aligned to above value and run from there. 2204 2205 If bootloader loads the kernel at a non-aligned address and 2206 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2207 load address and decompress itself to the address it has been 2208 compiled for and run from there. The address for which kernel is 2209 compiled already meets above alignment restrictions. Hence the 2210 end result is that kernel runs from a physical address meeting 2211 above alignment restrictions. 2212 2213 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2214 this value must be a multiple of 0x200000. 2215 2216 Don't change this unless you know what you are doing. 2217 2218config DYNAMIC_MEMORY_LAYOUT 2219 bool 2220 ---help--- 2221 This option makes base addresses of vmalloc and vmemmap as well as 2222 __PAGE_OFFSET movable during boot. 2223 2224config RANDOMIZE_MEMORY 2225 bool "Randomize the kernel memory sections" 2226 depends on X86_64 2227 depends on RANDOMIZE_BASE 2228 select DYNAMIC_MEMORY_LAYOUT 2229 default RANDOMIZE_BASE 2230 ---help--- 2231 Randomizes the base virtual address of kernel memory sections 2232 (physical memory mapping, vmalloc & vmemmap). This security feature 2233 makes exploits relying on predictable memory locations less reliable. 2234 2235 The order of allocations remains unchanged. Entropy is generated in 2236 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2237 configuration have in average 30,000 different possible virtual 2238 addresses for each memory section. 2239 2240 If unsure, say Y. 2241 2242config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2243 hex "Physical memory mapping padding" if EXPERT 2244 depends on RANDOMIZE_MEMORY 2245 default "0xa" if MEMORY_HOTPLUG 2246 default "0x0" 2247 range 0x1 0x40 if MEMORY_HOTPLUG 2248 range 0x0 0x40 2249 ---help--- 2250 Define the padding in terabytes added to the existing physical 2251 memory size during kernel memory randomization. It is useful 2252 for memory hotplug support but reduces the entropy available for 2253 address randomization. 2254 2255 If unsure, leave at the default value. 2256 2257config HOTPLUG_CPU 2258 def_bool y 2259 depends on SMP 2260 2261config BOOTPARAM_HOTPLUG_CPU0 2262 bool "Set default setting of cpu0_hotpluggable" 2263 depends on HOTPLUG_CPU 2264 ---help--- 2265 Set whether default state of cpu0_hotpluggable is on or off. 2266 2267 Say Y here to enable CPU0 hotplug by default. If this switch 2268 is turned on, there is no need to give cpu0_hotplug kernel 2269 parameter and the CPU0 hotplug feature is enabled by default. 2270 2271 Please note: there are two known CPU0 dependencies if you want 2272 to enable the CPU0 hotplug feature either by this switch or by 2273 cpu0_hotplug kernel parameter. 2274 2275 First, resume from hibernate or suspend always starts from CPU0. 2276 So hibernate and suspend are prevented if CPU0 is offline. 2277 2278 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2279 offline if any interrupt can not migrate out of CPU0. There may 2280 be other CPU0 dependencies. 2281 2282 Please make sure the dependencies are under your control before 2283 you enable this feature. 2284 2285 Say N if you don't want to enable CPU0 hotplug feature by default. 2286 You still can enable the CPU0 hotplug feature at boot by kernel 2287 parameter cpu0_hotplug. 2288 2289config DEBUG_HOTPLUG_CPU0 2290 def_bool n 2291 prompt "Debug CPU0 hotplug" 2292 depends on HOTPLUG_CPU 2293 ---help--- 2294 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2295 soon as possible and boots up userspace with CPU0 offlined. User 2296 can online CPU0 back after boot time. 2297 2298 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2299 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2300 compilation or giving cpu0_hotplug kernel parameter at boot. 2301 2302 If unsure, say N. 2303 2304config COMPAT_VDSO 2305 def_bool n 2306 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2307 depends on COMPAT_32 2308 ---help--- 2309 Certain buggy versions of glibc will crash if they are 2310 presented with a 32-bit vDSO that is not mapped at the address 2311 indicated in its segment table. 2312 2313 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2314 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2315 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2316 the only released version with the bug, but OpenSUSE 9 2317 contains a buggy "glibc 2.3.2". 2318 2319 The symptom of the bug is that everything crashes on startup, saying: 2320 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2321 2322 Saying Y here changes the default value of the vdso32 boot 2323 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2324 This works around the glibc bug but hurts performance. 2325 2326 If unsure, say N: if you are compiling your own kernel, you 2327 are unlikely to be using a buggy version of glibc. 2328 2329choice 2330 prompt "vsyscall table for legacy applications" 2331 depends on X86_64 2332 default LEGACY_VSYSCALL_XONLY 2333 help 2334 Legacy user code that does not know how to find the vDSO expects 2335 to be able to issue three syscalls by calling fixed addresses in 2336 kernel space. Since this location is not randomized with ASLR, 2337 it can be used to assist security vulnerability exploitation. 2338 2339 This setting can be changed at boot time via the kernel command 2340 line parameter vsyscall=[emulate|xonly|none]. 2341 2342 On a system with recent enough glibc (2.14 or newer) and no 2343 static binaries, you can say None without a performance penalty 2344 to improve security. 2345 2346 If unsure, select "Emulate execution only". 2347 2348 config LEGACY_VSYSCALL_EMULATE 2349 bool "Full emulation" 2350 help 2351 The kernel traps and emulates calls into the fixed vsyscall 2352 address mapping. This makes the mapping non-executable, but 2353 it still contains readable known contents, which could be 2354 used in certain rare security vulnerability exploits. This 2355 configuration is recommended when using legacy userspace 2356 that still uses vsyscalls along with legacy binary 2357 instrumentation tools that require code to be readable. 2358 2359 An example of this type of legacy userspace is running 2360 Pin on an old binary that still uses vsyscalls. 2361 2362 config LEGACY_VSYSCALL_XONLY 2363 bool "Emulate execution only" 2364 help 2365 The kernel traps and emulates calls into the fixed vsyscall 2366 address mapping and does not allow reads. This 2367 configuration is recommended when userspace might use the 2368 legacy vsyscall area but support for legacy binary 2369 instrumentation of legacy code is not needed. It mitigates 2370 certain uses of the vsyscall area as an ASLR-bypassing 2371 buffer. 2372 2373 config LEGACY_VSYSCALL_NONE 2374 bool "None" 2375 help 2376 There will be no vsyscall mapping at all. This will 2377 eliminate any risk of ASLR bypass due to the vsyscall 2378 fixed address mapping. Attempts to use the vsyscalls 2379 will be reported to dmesg, so that either old or 2380 malicious userspace programs can be identified. 2381 2382endchoice 2383 2384config CMDLINE_BOOL 2385 bool "Built-in kernel command line" 2386 ---help--- 2387 Allow for specifying boot arguments to the kernel at 2388 build time. On some systems (e.g. embedded ones), it is 2389 necessary or convenient to provide some or all of the 2390 kernel boot arguments with the kernel itself (that is, 2391 to not rely on the boot loader to provide them.) 2392 2393 To compile command line arguments into the kernel, 2394 set this option to 'Y', then fill in the 2395 boot arguments in CONFIG_CMDLINE. 2396 2397 Systems with fully functional boot loaders (i.e. non-embedded) 2398 should leave this option set to 'N'. 2399 2400config CMDLINE 2401 string "Built-in kernel command string" 2402 depends on CMDLINE_BOOL 2403 default "" 2404 ---help--- 2405 Enter arguments here that should be compiled into the kernel 2406 image and used at boot time. If the boot loader provides a 2407 command line at boot time, it is appended to this string to 2408 form the full kernel command line, when the system boots. 2409 2410 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2411 change this behavior. 2412 2413 In most cases, the command line (whether built-in or provided 2414 by the boot loader) should specify the device for the root 2415 file system. 2416 2417config CMDLINE_OVERRIDE 2418 bool "Built-in command line overrides boot loader arguments" 2419 depends on CMDLINE_BOOL && CMDLINE != "" 2420 ---help--- 2421 Set this option to 'Y' to have the kernel ignore the boot loader 2422 command line, and use ONLY the built-in command line. 2423 2424 This is used to work around broken boot loaders. This should 2425 be set to 'N' under normal conditions. 2426 2427config MODIFY_LDT_SYSCALL 2428 bool "Enable the LDT (local descriptor table)" if EXPERT 2429 default y 2430 ---help--- 2431 Linux can allow user programs to install a per-process x86 2432 Local Descriptor Table (LDT) using the modify_ldt(2) system 2433 call. This is required to run 16-bit or segmented code such as 2434 DOSEMU or some Wine programs. It is also used by some very old 2435 threading libraries. 2436 2437 Enabling this feature adds a small amount of overhead to 2438 context switches and increases the low-level kernel attack 2439 surface. Disabling it removes the modify_ldt(2) system call. 2440 2441 Saying 'N' here may make sense for embedded or server kernels. 2442 2443source "kernel/livepatch/Kconfig" 2444 2445endmenu 2446 2447config ARCH_HAS_ADD_PAGES 2448 def_bool y 2449 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2450 2451config ARCH_ENABLE_MEMORY_HOTPLUG 2452 def_bool y 2453 depends on X86_64 || (X86_32 && HIGHMEM) 2454 2455config ARCH_ENABLE_MEMORY_HOTREMOVE 2456 def_bool y 2457 depends on MEMORY_HOTPLUG 2458 2459config USE_PERCPU_NUMA_NODE_ID 2460 def_bool y 2461 depends on NUMA 2462 2463config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2464 def_bool y 2465 depends on X86_64 || X86_PAE 2466 2467config ARCH_ENABLE_HUGEPAGE_MIGRATION 2468 def_bool y 2469 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2470 2471config ARCH_ENABLE_THP_MIGRATION 2472 def_bool y 2473 depends on X86_64 && TRANSPARENT_HUGEPAGE 2474 2475menu "Power management and ACPI options" 2476 2477config ARCH_HIBERNATION_HEADER 2478 def_bool y 2479 depends on HIBERNATION 2480 2481source "kernel/power/Kconfig" 2482 2483source "drivers/acpi/Kconfig" 2484 2485source "drivers/sfi/Kconfig" 2486 2487config X86_APM_BOOT 2488 def_bool y 2489 depends on APM 2490 2491menuconfig APM 2492 tristate "APM (Advanced Power Management) BIOS support" 2493 depends on X86_32 && PM_SLEEP 2494 ---help--- 2495 APM is a BIOS specification for saving power using several different 2496 techniques. This is mostly useful for battery powered laptops with 2497 APM compliant BIOSes. If you say Y here, the system time will be 2498 reset after a RESUME operation, the /proc/apm device will provide 2499 battery status information, and user-space programs will receive 2500 notification of APM "events" (e.g. battery status change). 2501 2502 If you select "Y" here, you can disable actual use of the APM 2503 BIOS by passing the "apm=off" option to the kernel at boot time. 2504 2505 Note that the APM support is almost completely disabled for 2506 machines with more than one CPU. 2507 2508 In order to use APM, you will need supporting software. For location 2509 and more information, read <file:Documentation/power/apm-acpi.rst> 2510 and the Battery Powered Linux mini-HOWTO, available from 2511 <http://www.tldp.org/docs.html#howto>. 2512 2513 This driver does not spin down disk drives (see the hdparm(8) 2514 manpage ("man 8 hdparm") for that), and it doesn't turn off 2515 VESA-compliant "green" monitors. 2516 2517 This driver does not support the TI 4000M TravelMate and the ACER 2518 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2519 desktop machines also don't have compliant BIOSes, and this driver 2520 may cause those machines to panic during the boot phase. 2521 2522 Generally, if you don't have a battery in your machine, there isn't 2523 much point in using this driver and you should say N. If you get 2524 random kernel OOPSes or reboots that don't seem to be related to 2525 anything, try disabling/enabling this option (or disabling/enabling 2526 APM in your BIOS). 2527 2528 Some other things you should try when experiencing seemingly random, 2529 "weird" problems: 2530 2531 1) make sure that you have enough swap space and that it is 2532 enabled. 2533 2) pass the "no-hlt" option to the kernel 2534 3) switch on floating point emulation in the kernel and pass 2535 the "no387" option to the kernel 2536 4) pass the "floppy=nodma" option to the kernel 2537 5) pass the "mem=4M" option to the kernel (thereby disabling 2538 all but the first 4 MB of RAM) 2539 6) make sure that the CPU is not over clocked. 2540 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2541 8) disable the cache from your BIOS settings 2542 9) install a fan for the video card or exchange video RAM 2543 10) install a better fan for the CPU 2544 11) exchange RAM chips 2545 12) exchange the motherboard. 2546 2547 To compile this driver as a module, choose M here: the 2548 module will be called apm. 2549 2550if APM 2551 2552config APM_IGNORE_USER_SUSPEND 2553 bool "Ignore USER SUSPEND" 2554 ---help--- 2555 This option will ignore USER SUSPEND requests. On machines with a 2556 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2557 series notebooks, it is necessary to say Y because of a BIOS bug. 2558 2559config APM_DO_ENABLE 2560 bool "Enable PM at boot time" 2561 ---help--- 2562 Enable APM features at boot time. From page 36 of the APM BIOS 2563 specification: "When disabled, the APM BIOS does not automatically 2564 power manage devices, enter the Standby State, enter the Suspend 2565 State, or take power saving steps in response to CPU Idle calls." 2566 This driver will make CPU Idle calls when Linux is idle (unless this 2567 feature is turned off -- see "Do CPU IDLE calls", below). This 2568 should always save battery power, but more complicated APM features 2569 will be dependent on your BIOS implementation. You may need to turn 2570 this option off if your computer hangs at boot time when using APM 2571 support, or if it beeps continuously instead of suspending. Turn 2572 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2573 T400CDT. This is off by default since most machines do fine without 2574 this feature. 2575 2576config APM_CPU_IDLE 2577 depends on CPU_IDLE 2578 bool "Make CPU Idle calls when idle" 2579 ---help--- 2580 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2581 On some machines, this can activate improved power savings, such as 2582 a slowed CPU clock rate, when the machine is idle. These idle calls 2583 are made after the idle loop has run for some length of time (e.g., 2584 333 mS). On some machines, this will cause a hang at boot time or 2585 whenever the CPU becomes idle. (On machines with more than one CPU, 2586 this option does nothing.) 2587 2588config APM_DISPLAY_BLANK 2589 bool "Enable console blanking using APM" 2590 ---help--- 2591 Enable console blanking using the APM. Some laptops can use this to 2592 turn off the LCD backlight when the screen blanker of the Linux 2593 virtual console blanks the screen. Note that this is only used by 2594 the virtual console screen blanker, and won't turn off the backlight 2595 when using the X Window system. This also doesn't have anything to 2596 do with your VESA-compliant power-saving monitor. Further, this 2597 option doesn't work for all laptops -- it might not turn off your 2598 backlight at all, or it might print a lot of errors to the console, 2599 especially if you are using gpm. 2600 2601config APM_ALLOW_INTS 2602 bool "Allow interrupts during APM BIOS calls" 2603 ---help--- 2604 Normally we disable external interrupts while we are making calls to 2605 the APM BIOS as a measure to lessen the effects of a badly behaving 2606 BIOS implementation. The BIOS should reenable interrupts if it 2607 needs to. Unfortunately, some BIOSes do not -- especially those in 2608 many of the newer IBM Thinkpads. If you experience hangs when you 2609 suspend, try setting this to Y. Otherwise, say N. 2610 2611endif # APM 2612 2613source "drivers/cpufreq/Kconfig" 2614 2615source "drivers/cpuidle/Kconfig" 2616 2617source "drivers/idle/Kconfig" 2618 2619endmenu 2620 2621 2622menu "Bus options (PCI etc.)" 2623 2624choice 2625 prompt "PCI access mode" 2626 depends on X86_32 && PCI 2627 default PCI_GOANY 2628 ---help--- 2629 On PCI systems, the BIOS can be used to detect the PCI devices and 2630 determine their configuration. However, some old PCI motherboards 2631 have BIOS bugs and may crash if this is done. Also, some embedded 2632 PCI-based systems don't have any BIOS at all. Linux can also try to 2633 detect the PCI hardware directly without using the BIOS. 2634 2635 With this option, you can specify how Linux should detect the 2636 PCI devices. If you choose "BIOS", the BIOS will be used, 2637 if you choose "Direct", the BIOS won't be used, and if you 2638 choose "MMConfig", then PCI Express MMCONFIG will be used. 2639 If you choose "Any", the kernel will try MMCONFIG, then the 2640 direct access method and falls back to the BIOS if that doesn't 2641 work. If unsure, go with the default, which is "Any". 2642 2643config PCI_GOBIOS 2644 bool "BIOS" 2645 2646config PCI_GOMMCONFIG 2647 bool "MMConfig" 2648 2649config PCI_GODIRECT 2650 bool "Direct" 2651 2652config PCI_GOOLPC 2653 bool "OLPC XO-1" 2654 depends on OLPC 2655 2656config PCI_GOANY 2657 bool "Any" 2658 2659endchoice 2660 2661config PCI_BIOS 2662 def_bool y 2663 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2664 2665# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2666config PCI_DIRECT 2667 def_bool y 2668 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2669 2670config PCI_MMCONFIG 2671 bool "Support mmconfig PCI config space access" if X86_64 2672 default y 2673 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2674 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2675 2676config PCI_OLPC 2677 def_bool y 2678 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2679 2680config PCI_XEN 2681 def_bool y 2682 depends on PCI && XEN 2683 select SWIOTLB_XEN 2684 2685config MMCONF_FAM10H 2686 def_bool y 2687 depends on X86_64 && PCI_MMCONFIG && ACPI 2688 2689config PCI_CNB20LE_QUIRK 2690 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2691 depends on PCI 2692 help 2693 Read the PCI windows out of the CNB20LE host bridge. This allows 2694 PCI hotplug to work on systems with the CNB20LE chipset which do 2695 not have ACPI. 2696 2697 There's no public spec for this chipset, and this functionality 2698 is known to be incomplete. 2699 2700 You should say N unless you know you need this. 2701 2702config ISA_BUS 2703 bool "ISA bus support on modern systems" if EXPERT 2704 help 2705 Expose ISA bus device drivers and options available for selection and 2706 configuration. Enable this option if your target machine has an ISA 2707 bus. ISA is an older system, displaced by PCI and newer bus 2708 architectures -- if your target machine is modern, it probably does 2709 not have an ISA bus. 2710 2711 If unsure, say N. 2712 2713# x86_64 have no ISA slots, but can have ISA-style DMA. 2714config ISA_DMA_API 2715 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2716 default y 2717 help 2718 Enables ISA-style DMA support for devices requiring such controllers. 2719 If unsure, say Y. 2720 2721if X86_32 2722 2723config ISA 2724 bool "ISA support" 2725 ---help--- 2726 Find out whether you have ISA slots on your motherboard. ISA is the 2727 name of a bus system, i.e. the way the CPU talks to the other stuff 2728 inside your box. Other bus systems are PCI, EISA, MicroChannel 2729 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2730 newer boards don't support it. If you have ISA, say Y, otherwise N. 2731 2732config SCx200 2733 tristate "NatSemi SCx200 support" 2734 ---help--- 2735 This provides basic support for National Semiconductor's 2736 (now AMD's) Geode processors. The driver probes for the 2737 PCI-IDs of several on-chip devices, so its a good dependency 2738 for other scx200_* drivers. 2739 2740 If compiled as a module, the driver is named scx200. 2741 2742config SCx200HR_TIMER 2743 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2744 depends on SCx200 2745 default y 2746 ---help--- 2747 This driver provides a clocksource built upon the on-chip 2748 27MHz high-resolution timer. Its also a workaround for 2749 NSC Geode SC-1100's buggy TSC, which loses time when the 2750 processor goes idle (as is done by the scheduler). The 2751 other workaround is idle=poll boot option. 2752 2753config OLPC 2754 bool "One Laptop Per Child support" 2755 depends on !X86_PAE 2756 select GPIOLIB 2757 select OF 2758 select OF_PROMTREE 2759 select IRQ_DOMAIN 2760 select OLPC_EC 2761 ---help--- 2762 Add support for detecting the unique features of the OLPC 2763 XO hardware. 2764 2765config OLPC_XO1_PM 2766 bool "OLPC XO-1 Power Management" 2767 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2768 ---help--- 2769 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2770 2771config OLPC_XO1_RTC 2772 bool "OLPC XO-1 Real Time Clock" 2773 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2774 ---help--- 2775 Add support for the XO-1 real time clock, which can be used as a 2776 programmable wakeup source. 2777 2778config OLPC_XO1_SCI 2779 bool "OLPC XO-1 SCI extras" 2780 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2781 depends on INPUT=y 2782 select POWER_SUPPLY 2783 ---help--- 2784 Add support for SCI-based features of the OLPC XO-1 laptop: 2785 - EC-driven system wakeups 2786 - Power button 2787 - Ebook switch 2788 - Lid switch 2789 - AC adapter status updates 2790 - Battery status updates 2791 2792config OLPC_XO15_SCI 2793 bool "OLPC XO-1.5 SCI extras" 2794 depends on OLPC && ACPI 2795 select POWER_SUPPLY 2796 ---help--- 2797 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2798 - EC-driven system wakeups 2799 - AC adapter status updates 2800 - Battery status updates 2801 2802config ALIX 2803 bool "PCEngines ALIX System Support (LED setup)" 2804 select GPIOLIB 2805 ---help--- 2806 This option enables system support for the PCEngines ALIX. 2807 At present this just sets up LEDs for GPIO control on 2808 ALIX2/3/6 boards. However, other system specific setup should 2809 get added here. 2810 2811 Note: You must still enable the drivers for GPIO and LED support 2812 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2813 2814 Note: You have to set alix.force=1 for boards with Award BIOS. 2815 2816config NET5501 2817 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2818 select GPIOLIB 2819 ---help--- 2820 This option enables system support for the Soekris Engineering net5501. 2821 2822config GEOS 2823 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2824 select GPIOLIB 2825 depends on DMI 2826 ---help--- 2827 This option enables system support for the Traverse Technologies GEOS. 2828 2829config TS5500 2830 bool "Technologic Systems TS-5500 platform support" 2831 depends on MELAN 2832 select CHECK_SIGNATURE 2833 select NEW_LEDS 2834 select LEDS_CLASS 2835 ---help--- 2836 This option enables system support for the Technologic Systems TS-5500. 2837 2838endif # X86_32 2839 2840config AMD_NB 2841 def_bool y 2842 depends on CPU_SUP_AMD && PCI 2843 2844config X86_SYSFB 2845 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2846 help 2847 Firmwares often provide initial graphics framebuffers so the BIOS, 2848 bootloader or kernel can show basic video-output during boot for 2849 user-guidance and debugging. Historically, x86 used the VESA BIOS 2850 Extensions and EFI-framebuffers for this, which are mostly limited 2851 to x86. 2852 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2853 framebuffers so the new generic system-framebuffer drivers can be 2854 used on x86. If the framebuffer is not compatible with the generic 2855 modes, it is advertised as fallback platform framebuffer so legacy 2856 drivers like efifb, vesafb and uvesafb can pick it up. 2857 If this option is not selected, all system framebuffers are always 2858 marked as fallback platform framebuffers as usual. 2859 2860 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2861 not be able to pick up generic system framebuffers if this option 2862 is selected. You are highly encouraged to enable simplefb as 2863 replacement if you select this option. simplefb can correctly deal 2864 with generic system framebuffers. But you should still keep vesafb 2865 and others enabled as fallback if a system framebuffer is 2866 incompatible with simplefb. 2867 2868 If unsure, say Y. 2869 2870endmenu 2871 2872 2873menu "Binary Emulations" 2874 2875config IA32_EMULATION 2876 bool "IA32 Emulation" 2877 depends on X86_64 2878 select ARCH_WANT_OLD_COMPAT_IPC 2879 select BINFMT_ELF 2880 select COMPAT_BINFMT_ELF 2881 select COMPAT_OLD_SIGACTION 2882 ---help--- 2883 Include code to run legacy 32-bit programs under a 2884 64-bit kernel. You should likely turn this on, unless you're 2885 100% sure that you don't have any 32-bit programs left. 2886 2887config IA32_AOUT 2888 tristate "IA32 a.out support" 2889 depends on IA32_EMULATION 2890 depends on BROKEN 2891 ---help--- 2892 Support old a.out binaries in the 32bit emulation. 2893 2894config X86_X32 2895 bool "x32 ABI for 64-bit mode" 2896 depends on X86_64 2897 ---help--- 2898 Include code to run binaries for the x32 native 32-bit ABI 2899 for 64-bit processors. An x32 process gets access to the 2900 full 64-bit register file and wide data path while leaving 2901 pointers at 32 bits for smaller memory footprint. 2902 2903 You will need a recent binutils (2.22 or later) with 2904 elf32_x86_64 support enabled to compile a kernel with this 2905 option set. 2906 2907config COMPAT_32 2908 def_bool y 2909 depends on IA32_EMULATION || X86_32 2910 select HAVE_UID16 2911 select OLD_SIGSUSPEND3 2912 2913config COMPAT 2914 def_bool y 2915 depends on IA32_EMULATION || X86_X32 2916 2917if COMPAT 2918config COMPAT_FOR_U64_ALIGNMENT 2919 def_bool y 2920 2921config SYSVIPC_COMPAT 2922 def_bool y 2923 depends on SYSVIPC 2924endif 2925 2926endmenu 2927 2928 2929config HAVE_ATOMIC_IOMAP 2930 def_bool y 2931 depends on X86_32 2932 2933source "drivers/firmware/Kconfig" 2934 2935source "arch/x86/kvm/Kconfig" 2936 2937source "arch/x86/Kconfig.assembler" 2938