1# SPDX-License-Identifier: GPL-2.0 2# Select 32 or 64 bit 3config 64BIT 4 bool "64-bit kernel" if "$(ARCH)" = "x86" 5 default "$(ARCH)" != "i386" 6 ---help--- 7 Say yes to build a 64-bit kernel - formerly known as x86_64 8 Say no to build a 32-bit kernel - formerly known as i386 9 10config X86_32 11 def_bool y 12 depends on !64BIT 13 # Options that are inherently 32-bit kernel only: 14 select ARCH_WANT_IPC_PARSE_VERSION 15 select CLKSRC_I8253 16 select CLONE_BACKWARDS 17 select HAVE_DEBUG_STACKOVERFLOW 18 select MODULES_USE_ELF_REL 19 select OLD_SIGACTION 20 select GENERIC_VDSO_32 21 22config X86_64 23 def_bool y 24 depends on 64BIT 25 # Options that are inherently 64-bit kernel only: 26 select ARCH_HAS_GIGANTIC_PAGE 27 select ARCH_SUPPORTS_INT128 28 select ARCH_USE_CMPXCHG_LOCKREF 29 select HAVE_ARCH_SOFT_DIRTY 30 select MODULES_USE_ELF_RELA 31 select NEED_DMA_MAP_STATE 32 select SWIOTLB 33 select ARCH_HAS_SYSCALL_WRAPPER 34 35config FORCE_DYNAMIC_FTRACE 36 def_bool y 37 depends on X86_32 38 depends on FUNCTION_TRACER 39 select DYNAMIC_FTRACE 40 help 41 We keep the static function tracing (!DYNAMIC_FTRACE) around 42 in order to test the non static function tracing in the 43 generic code, as other architectures still use it. But we 44 only need to keep it around for x86_64. No need to keep it 45 for x86_32. For x86_32, force DYNAMIC_FTRACE. 46# 47# Arch settings 48# 49# ( Note that options that are marked 'if X86_64' could in principle be 50# ported to 32-bit as well. ) 51# 52config X86 53 def_bool y 54 # 55 # Note: keep this list sorted alphabetically 56 # 57 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 58 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 59 select ARCH_32BIT_OFF_T if X86_32 60 select ARCH_CLOCKSOURCE_DATA 61 select ARCH_CLOCKSOURCE_INIT 62 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 63 select ARCH_HAS_DEBUG_VIRTUAL 64 select ARCH_HAS_DEVMEM_IS_ALLOWED 65 select ARCH_HAS_ELF_RANDOMIZE 66 select ARCH_HAS_FAST_MULTIPLIER 67 select ARCH_HAS_FILTER_PGPROT 68 select ARCH_HAS_FORTIFY_SOURCE 69 select ARCH_HAS_GCOV_PROFILE_ALL 70 select ARCH_HAS_KCOV if X86_64 71 select ARCH_HAS_MEMBARRIER_SYNC_CORE 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_REFCOUNT 76 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 77 select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE 78 select ARCH_HAS_SET_MEMORY 79 select ARCH_HAS_SET_DIRECT_MAP 80 select ARCH_HAS_STRICT_KERNEL_RWX 81 select ARCH_HAS_STRICT_MODULE_RWX 82 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 83 select ARCH_HAS_UBSAN_SANITIZE_ALL 84 select ARCH_HAVE_NMI_SAFE_CMPXCHG 85 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 86 select ARCH_MIGHT_HAVE_PC_PARPORT 87 select ARCH_MIGHT_HAVE_PC_SERIO 88 select ARCH_STACKWALK 89 select ARCH_SUPPORTS_ACPI 90 select ARCH_SUPPORTS_ATOMIC_RMW 91 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 92 select ARCH_USE_BUILTIN_BSWAP 93 select ARCH_USE_QUEUED_RWLOCKS 94 select ARCH_USE_QUEUED_SPINLOCKS 95 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 96 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 97 select ARCH_WANT_HUGE_PMD_SHARE 98 select ARCH_WANTS_THP_SWAP if X86_64 99 select BUILDTIME_EXTABLE_SORT 100 select CLKEVT_I8253 101 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 102 select CLOCKSOURCE_WATCHDOG 103 select DCACHE_WORD_ACCESS 104 select EDAC_ATOMIC_SCRUB 105 select EDAC_SUPPORT 106 select GENERIC_CLOCKEVENTS 107 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 108 select GENERIC_CLOCKEVENTS_MIN_ADJUST 109 select GENERIC_CMOS_UPDATE 110 select GENERIC_CPU_AUTOPROBE 111 select GENERIC_CPU_VULNERABILITIES 112 select GENERIC_EARLY_IOREMAP 113 select GENERIC_FIND_FIRST_BIT 114 select GENERIC_IOMAP 115 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 116 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 117 select GENERIC_IRQ_MIGRATION if SMP 118 select GENERIC_IRQ_PROBE 119 select GENERIC_IRQ_RESERVATION_MODE 120 select GENERIC_IRQ_SHOW 121 select GENERIC_PENDING_IRQ if SMP 122 select GENERIC_SMP_IDLE_THREAD 123 select GENERIC_STRNCPY_FROM_USER 124 select GENERIC_STRNLEN_USER 125 select GENERIC_TIME_VSYSCALL 126 select GENERIC_GETTIMEOFDAY 127 select GUP_GET_PTE_LOW_HIGH if X86_PAE 128 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 129 select HAVE_ACPI_APEI if ACPI 130 select HAVE_ACPI_APEI_NMI if ACPI 131 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 132 select HAVE_ARCH_AUDITSYSCALL 133 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 134 select HAVE_ARCH_JUMP_LABEL 135 select HAVE_ARCH_JUMP_LABEL_RELATIVE 136 select HAVE_ARCH_KASAN if X86_64 137 select HAVE_ARCH_KGDB 138 select HAVE_ARCH_MMAP_RND_BITS if MMU 139 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 140 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 141 select HAVE_ARCH_PREL32_RELOCATIONS 142 select HAVE_ARCH_SECCOMP_FILTER 143 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 144 select HAVE_ARCH_STACKLEAK 145 select HAVE_ARCH_TRACEHOOK 146 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 147 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 148 select HAVE_ARCH_VMAP_STACK if X86_64 149 select HAVE_ARCH_WITHIN_STACK_FRAMES 150 select HAVE_CMPXCHG_DOUBLE 151 select HAVE_CMPXCHG_LOCAL 152 select HAVE_CONTEXT_TRACKING if X86_64 153 select HAVE_COPY_THREAD_TLS 154 select HAVE_C_RECORDMCOUNT 155 select HAVE_DEBUG_KMEMLEAK 156 select HAVE_DMA_CONTIGUOUS 157 select HAVE_DYNAMIC_FTRACE 158 select HAVE_DYNAMIC_FTRACE_WITH_REGS 159 select HAVE_EBPF_JIT 160 select HAVE_EFFICIENT_UNALIGNED_ACCESS 161 select HAVE_EISA 162 select HAVE_EXIT_THREAD 163 select HAVE_FAST_GUP 164 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 165 select HAVE_FTRACE_MCOUNT_RECORD 166 select HAVE_FUNCTION_GRAPH_TRACER 167 select HAVE_FUNCTION_TRACER 168 select HAVE_GCC_PLUGINS 169 select HAVE_HW_BREAKPOINT 170 select HAVE_IDE 171 select HAVE_IOREMAP_PROT 172 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 173 select HAVE_IRQ_TIME_ACCOUNTING 174 select HAVE_KERNEL_BZIP2 175 select HAVE_KERNEL_GZIP 176 select HAVE_KERNEL_LZ4 177 select HAVE_KERNEL_LZMA 178 select HAVE_KERNEL_LZO 179 select HAVE_KERNEL_XZ 180 select HAVE_KPROBES 181 select HAVE_KPROBES_ON_FTRACE 182 select HAVE_FUNCTION_ERROR_INJECTION 183 select HAVE_KRETPROBES 184 select HAVE_KVM 185 select HAVE_LIVEPATCH if X86_64 186 select HAVE_MEMBLOCK_NODE_MAP 187 select HAVE_MIXED_BREAKPOINTS_REGS 188 select HAVE_MOD_ARCH_SPECIFIC 189 select HAVE_MOVE_PMD 190 select HAVE_NMI 191 select HAVE_OPROFILE 192 select HAVE_OPTPROBES 193 select HAVE_PCSPKR_PLATFORM 194 select HAVE_PERF_EVENTS 195 select HAVE_PERF_EVENTS_NMI 196 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 197 select HAVE_PCI 198 select HAVE_PERF_REGS 199 select HAVE_PERF_USER_STACK_DUMP 200 select HAVE_RCU_TABLE_FREE if PARAVIRT 201 select HAVE_REGS_AND_STACK_ACCESS_API 202 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 203 select HAVE_FUNCTION_ARG_ACCESS_API 204 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 205 select HAVE_STACK_VALIDATION if X86_64 206 select HAVE_RSEQ 207 select HAVE_SYSCALL_TRACEPOINTS 208 select HAVE_UNSTABLE_SCHED_CLOCK 209 select HAVE_USER_RETURN_NOTIFIER 210 select HAVE_GENERIC_VDSO 211 select HOTPLUG_SMT if SMP 212 select IRQ_FORCED_THREADING 213 select NEED_SG_DMA_LENGTH 214 select PCI_DOMAINS if PCI 215 select PCI_LOCKLESS_CONFIG if PCI 216 select PERF_EVENTS 217 select RTC_LIB 218 select RTC_MC146818_LIB 219 select SPARSE_IRQ 220 select SRCU 221 select SYSCTL_EXCEPTION_TRACE 222 select THREAD_INFO_IN_TASK 223 select USER_STACKTRACE_SUPPORT 224 select VIRT_TO_BUS 225 select X86_FEATURE_NAMES if PROC_FS 226 select PROC_PID_ARCH_STATUS if PROC_FS 227 228config INSTRUCTION_DECODER 229 def_bool y 230 depends on KPROBES || PERF_EVENTS || UPROBES 231 232config OUTPUT_FORMAT 233 string 234 default "elf32-i386" if X86_32 235 default "elf64-x86-64" if X86_64 236 237config ARCH_DEFCONFIG 238 string 239 default "arch/x86/configs/i386_defconfig" if X86_32 240 default "arch/x86/configs/x86_64_defconfig" if X86_64 241 242config LOCKDEP_SUPPORT 243 def_bool y 244 245config STACKTRACE_SUPPORT 246 def_bool y 247 248config MMU 249 def_bool y 250 251config ARCH_MMAP_RND_BITS_MIN 252 default 28 if 64BIT 253 default 8 254 255config ARCH_MMAP_RND_BITS_MAX 256 default 32 if 64BIT 257 default 16 258 259config ARCH_MMAP_RND_COMPAT_BITS_MIN 260 default 8 261 262config ARCH_MMAP_RND_COMPAT_BITS_MAX 263 default 16 264 265config SBUS 266 bool 267 268config GENERIC_ISA_DMA 269 def_bool y 270 depends on ISA_DMA_API 271 272config GENERIC_BUG 273 def_bool y 274 depends on BUG 275 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 276 277config GENERIC_BUG_RELATIVE_POINTERS 278 bool 279 280config ARCH_MAY_HAVE_PC_FDC 281 def_bool y 282 depends on ISA_DMA_API 283 284config GENERIC_CALIBRATE_DELAY 285 def_bool y 286 287config ARCH_HAS_CPU_RELAX 288 def_bool y 289 290config ARCH_HAS_CACHE_LINE_SIZE 291 def_bool y 292 293config ARCH_HAS_FILTER_PGPROT 294 def_bool y 295 296config HAVE_SETUP_PER_CPU_AREA 297 def_bool y 298 299config NEED_PER_CPU_EMBED_FIRST_CHUNK 300 def_bool y 301 302config NEED_PER_CPU_PAGE_FIRST_CHUNK 303 def_bool y 304 305config ARCH_HIBERNATION_POSSIBLE 306 def_bool y 307 308config ARCH_SUSPEND_POSSIBLE 309 def_bool y 310 311config ARCH_WANT_GENERAL_HUGETLB 312 def_bool y 313 314config ZONE_DMA32 315 def_bool y if X86_64 316 317config AUDIT_ARCH 318 def_bool y if X86_64 319 320config ARCH_SUPPORTS_DEBUG_PAGEALLOC 321 def_bool y 322 323config KASAN_SHADOW_OFFSET 324 hex 325 depends on KASAN 326 default 0xdffffc0000000000 327 328config HAVE_INTEL_TXT 329 def_bool y 330 depends on INTEL_IOMMU && ACPI 331 332config X86_32_SMP 333 def_bool y 334 depends on X86_32 && SMP 335 336config X86_64_SMP 337 def_bool y 338 depends on X86_64 && SMP 339 340config X86_32_LAZY_GS 341 def_bool y 342 depends on X86_32 && !STACKPROTECTOR 343 344config ARCH_SUPPORTS_UPROBES 345 def_bool y 346 347config FIX_EARLYCON_MEM 348 def_bool y 349 350config DYNAMIC_PHYSICAL_MASK 351 bool 352 353config PGTABLE_LEVELS 354 int 355 default 5 if X86_5LEVEL 356 default 4 if X86_64 357 default 3 if X86_PAE 358 default 2 359 360config CC_HAS_SANE_STACKPROTECTOR 361 bool 362 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 363 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 364 help 365 We have to make sure stack protector is unconditionally disabled if 366 the compiler produces broken code. 367 368menu "Processor type and features" 369 370config ZONE_DMA 371 bool "DMA memory allocation support" if EXPERT 372 default y 373 help 374 DMA memory allocation support allows devices with less than 32-bit 375 addressing to allocate within the first 16MB of address space. 376 Disable if no such devices will be used. 377 378 If unsure, say Y. 379 380config SMP 381 bool "Symmetric multi-processing support" 382 ---help--- 383 This enables support for systems with more than one CPU. If you have 384 a system with only one CPU, say N. If you have a system with more 385 than one CPU, say Y. 386 387 If you say N here, the kernel will run on uni- and multiprocessor 388 machines, but will use only one CPU of a multiprocessor machine. If 389 you say Y here, the kernel will run on many, but not all, 390 uniprocessor machines. On a uniprocessor machine, the kernel 391 will run faster if you say N here. 392 393 Note that if you say Y here and choose architecture "586" or 394 "Pentium" under "Processor family", the kernel will not work on 486 395 architectures. Similarly, multiprocessor kernels for the "PPro" 396 architecture may not work on all Pentium based boards. 397 398 People using multiprocessor machines who say Y here should also say 399 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 400 Management" code will be disabled if you say Y here. 401 402 See also <file:Documentation/x86/i386/IO-APIC.rst>, 403 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 404 <http://www.tldp.org/docs.html#howto>. 405 406 If you don't know what to do here, say N. 407 408config X86_FEATURE_NAMES 409 bool "Processor feature human-readable names" if EMBEDDED 410 default y 411 ---help--- 412 This option compiles in a table of x86 feature bits and corresponding 413 names. This is required to support /proc/cpuinfo and a few kernel 414 messages. You can disable this to save space, at the expense of 415 making those few kernel messages show numeric feature bits instead. 416 417 If in doubt, say Y. 418 419config X86_X2APIC 420 bool "Support x2apic" 421 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 422 ---help--- 423 This enables x2apic support on CPUs that have this feature. 424 425 This allows 32-bit apic IDs (so it can support very large systems), 426 and accesses the local apic via MSRs not via mmio. 427 428 If you don't know what to do here, say N. 429 430config X86_MPPARSE 431 bool "Enable MPS table" if ACPI || SFI 432 default y 433 depends on X86_LOCAL_APIC 434 ---help--- 435 For old smp systems that do not have proper acpi support. Newer systems 436 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 437 438config GOLDFISH 439 def_bool y 440 depends on X86_GOLDFISH 441 442config RETPOLINE 443 bool "Avoid speculative indirect branches in kernel" 444 default y 445 select STACK_VALIDATION if HAVE_STACK_VALIDATION 446 help 447 Compile kernel with the retpoline compiler options to guard against 448 kernel-to-user data leaks by avoiding speculative indirect 449 branches. Requires a compiler with -mindirect-branch=thunk-extern 450 support for full protection. The kernel may run slower. 451 452config X86_CPU_RESCTRL 453 bool "x86 CPU resource control support" 454 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 455 select KERNFS 456 help 457 Enable x86 CPU resource control support. 458 459 Provide support for the allocation and monitoring of system resources 460 usage by the CPU. 461 462 Intel calls this Intel Resource Director Technology 463 (Intel(R) RDT). More information about RDT can be found in the 464 Intel x86 Architecture Software Developer Manual. 465 466 AMD calls this AMD Platform Quality of Service (AMD QoS). 467 More information about AMD QoS can be found in the AMD64 Technology 468 Platform Quality of Service Extensions manual. 469 470 Say N if unsure. 471 472if X86_32 473config X86_BIGSMP 474 bool "Support for big SMP systems with more than 8 CPUs" 475 depends on SMP 476 ---help--- 477 This option is needed for the systems that have more than 8 CPUs 478 479config X86_EXTENDED_PLATFORM 480 bool "Support for extended (non-PC) x86 platforms" 481 default y 482 ---help--- 483 If you disable this option then the kernel will only support 484 standard PC platforms. (which covers the vast majority of 485 systems out there.) 486 487 If you enable this option then you'll be able to select support 488 for the following (non-PC) 32 bit x86 platforms: 489 Goldfish (Android emulator) 490 AMD Elan 491 RDC R-321x SoC 492 SGI 320/540 (Visual Workstation) 493 STA2X11-based (e.g. Northville) 494 Moorestown MID devices 495 496 If you have one of these systems, or if you want to build a 497 generic distribution kernel, say Y here - otherwise say N. 498endif 499 500if X86_64 501config X86_EXTENDED_PLATFORM 502 bool "Support for extended (non-PC) x86 platforms" 503 default y 504 ---help--- 505 If you disable this option then the kernel will only support 506 standard PC platforms. (which covers the vast majority of 507 systems out there.) 508 509 If you enable this option then you'll be able to select support 510 for the following (non-PC) 64 bit x86 platforms: 511 Numascale NumaChip 512 ScaleMP vSMP 513 SGI Ultraviolet 514 515 If you have one of these systems, or if you want to build a 516 generic distribution kernel, say Y here - otherwise say N. 517endif 518# This is an alphabetically sorted list of 64 bit extended platforms 519# Please maintain the alphabetic order if and when there are additions 520config X86_NUMACHIP 521 bool "Numascale NumaChip" 522 depends on X86_64 523 depends on X86_EXTENDED_PLATFORM 524 depends on NUMA 525 depends on SMP 526 depends on X86_X2APIC 527 depends on PCI_MMCONFIG 528 ---help--- 529 Adds support for Numascale NumaChip large-SMP systems. Needed to 530 enable more than ~168 cores. 531 If you don't have one of these, you should say N here. 532 533config X86_VSMP 534 bool "ScaleMP vSMP" 535 select HYPERVISOR_GUEST 536 select PARAVIRT 537 depends on X86_64 && PCI 538 depends on X86_EXTENDED_PLATFORM 539 depends on SMP 540 ---help--- 541 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 542 supposed to run on these EM64T-based machines. Only choose this option 543 if you have one of these machines. 544 545config X86_UV 546 bool "SGI Ultraviolet" 547 depends on X86_64 548 depends on X86_EXTENDED_PLATFORM 549 depends on NUMA 550 depends on EFI 551 depends on X86_X2APIC 552 depends on PCI 553 ---help--- 554 This option is needed in order to support SGI Ultraviolet systems. 555 If you don't have one of these, you should say N here. 556 557# Following is an alphabetically sorted list of 32 bit extended platforms 558# Please maintain the alphabetic order if and when there are additions 559 560config X86_GOLDFISH 561 bool "Goldfish (Virtual Platform)" 562 depends on X86_EXTENDED_PLATFORM 563 ---help--- 564 Enable support for the Goldfish virtual platform used primarily 565 for Android development. Unless you are building for the Android 566 Goldfish emulator say N here. 567 568config X86_INTEL_CE 569 bool "CE4100 TV platform" 570 depends on PCI 571 depends on PCI_GODIRECT 572 depends on X86_IO_APIC 573 depends on X86_32 574 depends on X86_EXTENDED_PLATFORM 575 select X86_REBOOTFIXUPS 576 select OF 577 select OF_EARLY_FLATTREE 578 ---help--- 579 Select for the Intel CE media processor (CE4100) SOC. 580 This option compiles in support for the CE4100 SOC for settop 581 boxes and media devices. 582 583config X86_INTEL_MID 584 bool "Intel MID platform support" 585 depends on X86_EXTENDED_PLATFORM 586 depends on X86_PLATFORM_DEVICES 587 depends on PCI 588 depends on X86_64 || (PCI_GOANY && X86_32) 589 depends on X86_IO_APIC 590 select SFI 591 select I2C 592 select DW_APB_TIMER 593 select APB_TIMER 594 select INTEL_SCU_IPC 595 select MFD_INTEL_MSIC 596 ---help--- 597 Select to build a kernel capable of supporting Intel MID (Mobile 598 Internet Device) platform systems which do not have the PCI legacy 599 interfaces. If you are building for a PC class system say N here. 600 601 Intel MID platforms are based on an Intel processor and chipset which 602 consume less power than most of the x86 derivatives. 603 604config X86_INTEL_QUARK 605 bool "Intel Quark platform support" 606 depends on X86_32 607 depends on X86_EXTENDED_PLATFORM 608 depends on X86_PLATFORM_DEVICES 609 depends on X86_TSC 610 depends on PCI 611 depends on PCI_GOANY 612 depends on X86_IO_APIC 613 select IOSF_MBI 614 select INTEL_IMR 615 select COMMON_CLK 616 ---help--- 617 Select to include support for Quark X1000 SoC. 618 Say Y here if you have a Quark based system such as the Arduino 619 compatible Intel Galileo. 620 621config X86_INTEL_LPSS 622 bool "Intel Low Power Subsystem Support" 623 depends on X86 && ACPI && PCI 624 select COMMON_CLK 625 select PINCTRL 626 select IOSF_MBI 627 ---help--- 628 Select to build support for Intel Low Power Subsystem such as 629 found on Intel Lynxpoint PCH. Selecting this option enables 630 things like clock tree (common clock framework) and pincontrol 631 which are needed by the LPSS peripheral drivers. 632 633config X86_AMD_PLATFORM_DEVICE 634 bool "AMD ACPI2Platform devices support" 635 depends on ACPI 636 select COMMON_CLK 637 select PINCTRL 638 ---help--- 639 Select to interpret AMD specific ACPI device to platform device 640 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 641 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 642 implemented under PINCTRL subsystem. 643 644config IOSF_MBI 645 tristate "Intel SoC IOSF Sideband support for SoC platforms" 646 depends on PCI 647 ---help--- 648 This option enables sideband register access support for Intel SoC 649 platforms. On these platforms the IOSF sideband is used in lieu of 650 MSR's for some register accesses, mostly but not limited to thermal 651 and power. Drivers may query the availability of this device to 652 determine if they need the sideband in order to work on these 653 platforms. The sideband is available on the following SoC products. 654 This list is not meant to be exclusive. 655 - BayTrail 656 - Braswell 657 - Quark 658 659 You should say Y if you are running a kernel on one of these SoC's. 660 661config IOSF_MBI_DEBUG 662 bool "Enable IOSF sideband access through debugfs" 663 depends on IOSF_MBI && DEBUG_FS 664 ---help--- 665 Select this option to expose the IOSF sideband access registers (MCR, 666 MDR, MCRX) through debugfs to write and read register information from 667 different units on the SoC. This is most useful for obtaining device 668 state information for debug and analysis. As this is a general access 669 mechanism, users of this option would have specific knowledge of the 670 device they want to access. 671 672 If you don't require the option or are in doubt, say N. 673 674config X86_RDC321X 675 bool "RDC R-321x SoC" 676 depends on X86_32 677 depends on X86_EXTENDED_PLATFORM 678 select M486 679 select X86_REBOOTFIXUPS 680 ---help--- 681 This option is needed for RDC R-321x system-on-chip, also known 682 as R-8610-(G). 683 If you don't have one of these chips, you should say N here. 684 685config X86_32_NON_STANDARD 686 bool "Support non-standard 32-bit SMP architectures" 687 depends on X86_32 && SMP 688 depends on X86_EXTENDED_PLATFORM 689 ---help--- 690 This option compiles in the bigsmp and STA2X11 default 691 subarchitectures. It is intended for a generic binary 692 kernel. If you select them all, kernel will probe it one by 693 one and will fallback to default. 694 695# Alphabetically sorted list of Non standard 32 bit platforms 696 697config X86_SUPPORTS_MEMORY_FAILURE 698 def_bool y 699 # MCE code calls memory_failure(): 700 depends on X86_MCE 701 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 702 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 703 depends on X86_64 || !SPARSEMEM 704 select ARCH_SUPPORTS_MEMORY_FAILURE 705 706config STA2X11 707 bool "STA2X11 Companion Chip Support" 708 depends on X86_32_NON_STANDARD && PCI 709 select ARCH_HAS_PHYS_TO_DMA 710 select SWIOTLB 711 select MFD_STA2X11 712 select GPIOLIB 713 ---help--- 714 This adds support for boards based on the STA2X11 IO-Hub, 715 a.k.a. "ConneXt". The chip is used in place of the standard 716 PC chipset, so all "standard" peripherals are missing. If this 717 option is selected the kernel will still be able to boot on 718 standard PC machines. 719 720config X86_32_IRIS 721 tristate "Eurobraille/Iris poweroff module" 722 depends on X86_32 723 ---help--- 724 The Iris machines from EuroBraille do not have APM or ACPI support 725 to shut themselves down properly. A special I/O sequence is 726 needed to do so, which is what this module does at 727 kernel shutdown. 728 729 This is only for Iris machines from EuroBraille. 730 731 If unused, say N. 732 733config SCHED_OMIT_FRAME_POINTER 734 def_bool y 735 prompt "Single-depth WCHAN output" 736 depends on X86 737 ---help--- 738 Calculate simpler /proc/<PID>/wchan values. If this option 739 is disabled then wchan values will recurse back to the 740 caller function. This provides more accurate wchan values, 741 at the expense of slightly more scheduling overhead. 742 743 If in doubt, say "Y". 744 745menuconfig HYPERVISOR_GUEST 746 bool "Linux guest support" 747 ---help--- 748 Say Y here to enable options for running Linux under various hyper- 749 visors. This option enables basic hypervisor detection and platform 750 setup. 751 752 If you say N, all options in this submenu will be skipped and 753 disabled, and Linux guest support won't be built in. 754 755if HYPERVISOR_GUEST 756 757config PARAVIRT 758 bool "Enable paravirtualization code" 759 ---help--- 760 This changes the kernel so it can modify itself when it is run 761 under a hypervisor, potentially improving performance significantly 762 over full virtualization. However, when run without a hypervisor 763 the kernel is theoretically slower and slightly larger. 764 765config PARAVIRT_XXL 766 bool 767 768config PARAVIRT_DEBUG 769 bool "paravirt-ops debugging" 770 depends on PARAVIRT && DEBUG_KERNEL 771 ---help--- 772 Enable to debug paravirt_ops internals. Specifically, BUG if 773 a paravirt_op is missing when it is called. 774 775config PARAVIRT_SPINLOCKS 776 bool "Paravirtualization layer for spinlocks" 777 depends on PARAVIRT && SMP 778 ---help--- 779 Paravirtualized spinlocks allow a pvops backend to replace the 780 spinlock implementation with something virtualization-friendly 781 (for example, block the virtual CPU rather than spinning). 782 783 It has a minimal impact on native kernels and gives a nice performance 784 benefit on paravirtualized KVM / Xen kernels. 785 786 If you are unsure how to answer this question, answer Y. 787 788config X86_HV_CALLBACK_VECTOR 789 def_bool n 790 791source "arch/x86/xen/Kconfig" 792 793config KVM_GUEST 794 bool "KVM Guest support (including kvmclock)" 795 depends on PARAVIRT 796 select PARAVIRT_CLOCK 797 select ARCH_CPUIDLE_HALTPOLL 798 default y 799 ---help--- 800 This option enables various optimizations for running under the KVM 801 hypervisor. It includes a paravirtualized clock, so that instead 802 of relying on a PIT (or probably other) emulation by the 803 underlying device model, the host provides the guest with 804 timing infrastructure such as time of day, and system time 805 806config ARCH_CPUIDLE_HALTPOLL 807 def_bool n 808 prompt "Disable host haltpoll when loading haltpoll driver" 809 help 810 If virtualized under KVM, disable host haltpoll. 811 812config PVH 813 bool "Support for running PVH guests" 814 ---help--- 815 This option enables the PVH entry point for guest virtual machines 816 as specified in the x86/HVM direct boot ABI. 817 818config KVM_DEBUG_FS 819 bool "Enable debug information for KVM Guests in debugfs" 820 depends on KVM_GUEST && DEBUG_FS 821 ---help--- 822 This option enables collection of various statistics for KVM guest. 823 Statistics are displayed in debugfs filesystem. Enabling this option 824 may incur significant overhead. 825 826config PARAVIRT_TIME_ACCOUNTING 827 bool "Paravirtual steal time accounting" 828 depends on PARAVIRT 829 ---help--- 830 Select this option to enable fine granularity task steal time 831 accounting. Time spent executing other tasks in parallel with 832 the current vCPU is discounted from the vCPU power. To account for 833 that, there can be a small performance impact. 834 835 If in doubt, say N here. 836 837config PARAVIRT_CLOCK 838 bool 839 840config JAILHOUSE_GUEST 841 bool "Jailhouse non-root cell support" 842 depends on X86_64 && PCI 843 select X86_PM_TIMER 844 ---help--- 845 This option allows to run Linux as guest in a Jailhouse non-root 846 cell. You can leave this option disabled if you only want to start 847 Jailhouse and run Linux afterwards in the root cell. 848 849config ACRN_GUEST 850 bool "ACRN Guest support" 851 depends on X86_64 852 select X86_HV_CALLBACK_VECTOR 853 help 854 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 855 a flexible, lightweight reference open-source hypervisor, built with 856 real-time and safety-criticality in mind. It is built for embedded 857 IOT with small footprint and real-time features. More details can be 858 found in https://projectacrn.org/. 859 860endif #HYPERVISOR_GUEST 861 862source "arch/x86/Kconfig.cpu" 863 864config HPET_TIMER 865 def_bool X86_64 866 prompt "HPET Timer Support" if X86_32 867 ---help--- 868 Use the IA-PC HPET (High Precision Event Timer) to manage 869 time in preference to the PIT and RTC, if a HPET is 870 present. 871 HPET is the next generation timer replacing legacy 8254s. 872 The HPET provides a stable time base on SMP 873 systems, unlike the TSC, but it is more expensive to access, 874 as it is off-chip. The interface used is documented 875 in the HPET spec, revision 1. 876 877 You can safely choose Y here. However, HPET will only be 878 activated if the platform and the BIOS support this feature. 879 Otherwise the 8254 will be used for timing services. 880 881 Choose N to continue using the legacy 8254 timer. 882 883config HPET_EMULATE_RTC 884 def_bool y 885 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 886 887config APB_TIMER 888 def_bool y if X86_INTEL_MID 889 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 890 select DW_APB_TIMER 891 depends on X86_INTEL_MID && SFI 892 help 893 APB timer is the replacement for 8254, HPET on X86 MID platforms. 894 The APBT provides a stable time base on SMP 895 systems, unlike the TSC, but it is more expensive to access, 896 as it is off-chip. APB timers are always running regardless of CPU 897 C states, they are used as per CPU clockevent device when possible. 898 899# Mark as expert because too many people got it wrong. 900# The code disables itself when not needed. 901config DMI 902 default y 903 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 904 bool "Enable DMI scanning" if EXPERT 905 ---help--- 906 Enabled scanning of DMI to identify machine quirks. Say Y 907 here unless you have verified that your setup is not 908 affected by entries in the DMI blacklist. Required by PNP 909 BIOS code. 910 911config GART_IOMMU 912 bool "Old AMD GART IOMMU support" 913 select IOMMU_HELPER 914 select SWIOTLB 915 depends on X86_64 && PCI && AMD_NB 916 ---help--- 917 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 918 GART based hardware IOMMUs. 919 920 The GART supports full DMA access for devices with 32-bit access 921 limitations, on systems with more than 3 GB. This is usually needed 922 for USB, sound, many IDE/SATA chipsets and some other devices. 923 924 Newer systems typically have a modern AMD IOMMU, supported via 925 the CONFIG_AMD_IOMMU=y config option. 926 927 In normal configurations this driver is only active when needed: 928 there's more than 3 GB of memory and the system contains a 929 32-bit limited device. 930 931 If unsure, say Y. 932 933config CALGARY_IOMMU 934 bool "IBM Calgary IOMMU support" 935 select IOMMU_HELPER 936 select SWIOTLB 937 depends on X86_64 && PCI 938 ---help--- 939 Support for hardware IOMMUs in IBM's xSeries x366 and x460 940 systems. Needed to run systems with more than 3GB of memory 941 properly with 32-bit PCI devices that do not support DAC 942 (Double Address Cycle). Calgary also supports bus level 943 isolation, where all DMAs pass through the IOMMU. This 944 prevents them from going anywhere except their intended 945 destination. This catches hard-to-find kernel bugs and 946 mis-behaving drivers and devices that do not use the DMA-API 947 properly to set up their DMA buffers. The IOMMU can be 948 turned off at boot time with the iommu=off parameter. 949 Normally the kernel will make the right choice by itself. 950 If unsure, say Y. 951 952config CALGARY_IOMMU_ENABLED_BY_DEFAULT 953 def_bool y 954 prompt "Should Calgary be enabled by default?" 955 depends on CALGARY_IOMMU 956 ---help--- 957 Should Calgary be enabled by default? if you choose 'y', Calgary 958 will be used (if it exists). If you choose 'n', Calgary will not be 959 used even if it exists. If you choose 'n' and would like to use 960 Calgary anyway, pass 'iommu=calgary' on the kernel command line. 961 If unsure, say Y. 962 963config MAXSMP 964 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 965 depends on X86_64 && SMP && DEBUG_KERNEL 966 select CPUMASK_OFFSTACK 967 ---help--- 968 Enable maximum number of CPUS and NUMA Nodes for this architecture. 969 If unsure, say N. 970 971# 972# The maximum number of CPUs supported: 973# 974# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 975# and which can be configured interactively in the 976# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 977# 978# The ranges are different on 32-bit and 64-bit kernels, depending on 979# hardware capabilities and scalability features of the kernel. 980# 981# ( If MAXSMP is enabled we just use the highest possible value and disable 982# interactive configuration. ) 983# 984 985config NR_CPUS_RANGE_BEGIN 986 int 987 default NR_CPUS_RANGE_END if MAXSMP 988 default 1 if !SMP 989 default 2 990 991config NR_CPUS_RANGE_END 992 int 993 depends on X86_32 994 default 64 if SMP && X86_BIGSMP 995 default 8 if SMP && !X86_BIGSMP 996 default 1 if !SMP 997 998config NR_CPUS_RANGE_END 999 int 1000 depends on X86_64 1001 default 8192 if SMP && ( MAXSMP || CPUMASK_OFFSTACK) 1002 default 512 if SMP && (!MAXSMP && !CPUMASK_OFFSTACK) 1003 default 1 if !SMP 1004 1005config NR_CPUS_DEFAULT 1006 int 1007 depends on X86_32 1008 default 32 if X86_BIGSMP 1009 default 8 if SMP 1010 default 1 if !SMP 1011 1012config NR_CPUS_DEFAULT 1013 int 1014 depends on X86_64 1015 default 8192 if MAXSMP 1016 default 64 if SMP 1017 default 1 if !SMP 1018 1019config NR_CPUS 1020 int "Maximum number of CPUs" if SMP && !MAXSMP 1021 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1022 default NR_CPUS_DEFAULT 1023 ---help--- 1024 This allows you to specify the maximum number of CPUs which this 1025 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1026 supported value is 8192, otherwise the maximum value is 512. The 1027 minimum value which makes sense is 2. 1028 1029 This is purely to save memory: each supported CPU adds about 8KB 1030 to the kernel image. 1031 1032config SCHED_SMT 1033 def_bool y if SMP 1034 1035config SCHED_MC 1036 def_bool y 1037 prompt "Multi-core scheduler support" 1038 depends on SMP 1039 ---help--- 1040 Multi-core scheduler support improves the CPU scheduler's decision 1041 making when dealing with multi-core CPU chips at a cost of slightly 1042 increased overhead in some places. If unsure say N here. 1043 1044config SCHED_MC_PRIO 1045 bool "CPU core priorities scheduler support" 1046 depends on SCHED_MC && CPU_SUP_INTEL 1047 select X86_INTEL_PSTATE 1048 select CPU_FREQ 1049 default y 1050 ---help--- 1051 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1052 core ordering determined at manufacturing time, which allows 1053 certain cores to reach higher turbo frequencies (when running 1054 single threaded workloads) than others. 1055 1056 Enabling this kernel feature teaches the scheduler about 1057 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1058 scheduler's CPU selection logic accordingly, so that higher 1059 overall system performance can be achieved. 1060 1061 This feature will have no effect on CPUs without this feature. 1062 1063 If unsure say Y here. 1064 1065config UP_LATE_INIT 1066 def_bool y 1067 depends on !SMP && X86_LOCAL_APIC 1068 1069config X86_UP_APIC 1070 bool "Local APIC support on uniprocessors" if !PCI_MSI 1071 default PCI_MSI 1072 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1073 ---help--- 1074 A local APIC (Advanced Programmable Interrupt Controller) is an 1075 integrated interrupt controller in the CPU. If you have a single-CPU 1076 system which has a processor with a local APIC, you can say Y here to 1077 enable and use it. If you say Y here even though your machine doesn't 1078 have a local APIC, then the kernel will still run with no slowdown at 1079 all. The local APIC supports CPU-generated self-interrupts (timer, 1080 performance counters), and the NMI watchdog which detects hard 1081 lockups. 1082 1083config X86_UP_IOAPIC 1084 bool "IO-APIC support on uniprocessors" 1085 depends on X86_UP_APIC 1086 ---help--- 1087 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1088 SMP-capable replacement for PC-style interrupt controllers. Most 1089 SMP systems and many recent uniprocessor systems have one. 1090 1091 If you have a single-CPU system with an IO-APIC, you can say Y here 1092 to use it. If you say Y here even though your machine doesn't have 1093 an IO-APIC, then the kernel will still run with no slowdown at all. 1094 1095config X86_LOCAL_APIC 1096 def_bool y 1097 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1098 select IRQ_DOMAIN_HIERARCHY 1099 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1100 1101config X86_IO_APIC 1102 def_bool y 1103 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1104 1105config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1106 bool "Reroute for broken boot IRQs" 1107 depends on X86_IO_APIC 1108 ---help--- 1109 This option enables a workaround that fixes a source of 1110 spurious interrupts. This is recommended when threaded 1111 interrupt handling is used on systems where the generation of 1112 superfluous "boot interrupts" cannot be disabled. 1113 1114 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1115 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1116 kernel does during interrupt handling). On chipsets where this 1117 boot IRQ generation cannot be disabled, this workaround keeps 1118 the original IRQ line masked so that only the equivalent "boot 1119 IRQ" is delivered to the CPUs. The workaround also tells the 1120 kernel to set up the IRQ handler on the boot IRQ line. In this 1121 way only one interrupt is delivered to the kernel. Otherwise 1122 the spurious second interrupt may cause the kernel to bring 1123 down (vital) interrupt lines. 1124 1125 Only affects "broken" chipsets. Interrupt sharing may be 1126 increased on these systems. 1127 1128config X86_MCE 1129 bool "Machine Check / overheating reporting" 1130 select GENERIC_ALLOCATOR 1131 default y 1132 ---help--- 1133 Machine Check support allows the processor to notify the 1134 kernel if it detects a problem (e.g. overheating, data corruption). 1135 The action the kernel takes depends on the severity of the problem, 1136 ranging from warning messages to halting the machine. 1137 1138config X86_MCELOG_LEGACY 1139 bool "Support for deprecated /dev/mcelog character device" 1140 depends on X86_MCE 1141 ---help--- 1142 Enable support for /dev/mcelog which is needed by the old mcelog 1143 userspace logging daemon. Consider switching to the new generation 1144 rasdaemon solution. 1145 1146config X86_MCE_INTEL 1147 def_bool y 1148 prompt "Intel MCE features" 1149 depends on X86_MCE && X86_LOCAL_APIC 1150 ---help--- 1151 Additional support for intel specific MCE features such as 1152 the thermal monitor. 1153 1154config X86_MCE_AMD 1155 def_bool y 1156 prompt "AMD MCE features" 1157 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1158 ---help--- 1159 Additional support for AMD specific MCE features such as 1160 the DRAM Error Threshold. 1161 1162config X86_ANCIENT_MCE 1163 bool "Support for old Pentium 5 / WinChip machine checks" 1164 depends on X86_32 && X86_MCE 1165 ---help--- 1166 Include support for machine check handling on old Pentium 5 or WinChip 1167 systems. These typically need to be enabled explicitly on the command 1168 line. 1169 1170config X86_MCE_THRESHOLD 1171 depends on X86_MCE_AMD || X86_MCE_INTEL 1172 def_bool y 1173 1174config X86_MCE_INJECT 1175 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1176 tristate "Machine check injector support" 1177 ---help--- 1178 Provide support for injecting machine checks for testing purposes. 1179 If you don't know what a machine check is and you don't do kernel 1180 QA it is safe to say n. 1181 1182config X86_THERMAL_VECTOR 1183 def_bool y 1184 depends on X86_MCE_INTEL 1185 1186source "arch/x86/events/Kconfig" 1187 1188config X86_LEGACY_VM86 1189 bool "Legacy VM86 support" 1190 depends on X86_32 1191 ---help--- 1192 This option allows user programs to put the CPU into V8086 1193 mode, which is an 80286-era approximation of 16-bit real mode. 1194 1195 Some very old versions of X and/or vbetool require this option 1196 for user mode setting. Similarly, DOSEMU will use it if 1197 available to accelerate real mode DOS programs. However, any 1198 recent version of DOSEMU, X, or vbetool should be fully 1199 functional even without kernel VM86 support, as they will all 1200 fall back to software emulation. Nevertheless, if you are using 1201 a 16-bit DOS program where 16-bit performance matters, vm86 1202 mode might be faster than emulation and you might want to 1203 enable this option. 1204 1205 Note that any app that works on a 64-bit kernel is unlikely to 1206 need this option, as 64-bit kernels don't, and can't, support 1207 V8086 mode. This option is also unrelated to 16-bit protected 1208 mode and is not needed to run most 16-bit programs under Wine. 1209 1210 Enabling this option increases the complexity of the kernel 1211 and slows down exception handling a tiny bit. 1212 1213 If unsure, say N here. 1214 1215config VM86 1216 bool 1217 default X86_LEGACY_VM86 1218 1219config X86_16BIT 1220 bool "Enable support for 16-bit segments" if EXPERT 1221 default y 1222 depends on MODIFY_LDT_SYSCALL 1223 ---help--- 1224 This option is required by programs like Wine to run 16-bit 1225 protected mode legacy code on x86 processors. Disabling 1226 this option saves about 300 bytes on i386, or around 6K text 1227 plus 16K runtime memory on x86-64, 1228 1229config X86_ESPFIX32 1230 def_bool y 1231 depends on X86_16BIT && X86_32 1232 1233config X86_ESPFIX64 1234 def_bool y 1235 depends on X86_16BIT && X86_64 1236 1237config X86_VSYSCALL_EMULATION 1238 bool "Enable vsyscall emulation" if EXPERT 1239 default y 1240 depends on X86_64 1241 ---help--- 1242 This enables emulation of the legacy vsyscall page. Disabling 1243 it is roughly equivalent to booting with vsyscall=none, except 1244 that it will also disable the helpful warning if a program 1245 tries to use a vsyscall. With this option set to N, offending 1246 programs will just segfault, citing addresses of the form 1247 0xffffffffff600?00. 1248 1249 This option is required by many programs built before 2013, and 1250 care should be used even with newer programs if set to N. 1251 1252 Disabling this option saves about 7K of kernel size and 1253 possibly 4K of additional runtime pagetable memory. 1254 1255config TOSHIBA 1256 tristate "Toshiba Laptop support" 1257 depends on X86_32 1258 ---help--- 1259 This adds a driver to safely access the System Management Mode of 1260 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1261 not work on models with a Phoenix BIOS. The System Management Mode 1262 is used to set the BIOS and power saving options on Toshiba portables. 1263 1264 For information on utilities to make use of this driver see the 1265 Toshiba Linux utilities web site at: 1266 <http://www.buzzard.org.uk/toshiba/>. 1267 1268 Say Y if you intend to run this kernel on a Toshiba portable. 1269 Say N otherwise. 1270 1271config I8K 1272 tristate "Dell i8k legacy laptop support" 1273 select HWMON 1274 select SENSORS_DELL_SMM 1275 ---help--- 1276 This option enables legacy /proc/i8k userspace interface in hwmon 1277 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1278 temperature and allows controlling fan speeds of Dell laptops via 1279 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1280 it reports also power and hotkey status. For fan speed control is 1281 needed userspace package i8kutils. 1282 1283 Say Y if you intend to run this kernel on old Dell laptops or want to 1284 use userspace package i8kutils. 1285 Say N otherwise. 1286 1287config X86_REBOOTFIXUPS 1288 bool "Enable X86 board specific fixups for reboot" 1289 depends on X86_32 1290 ---help--- 1291 This enables chipset and/or board specific fixups to be done 1292 in order to get reboot to work correctly. This is only needed on 1293 some combinations of hardware and BIOS. The symptom, for which 1294 this config is intended, is when reboot ends with a stalled/hung 1295 system. 1296 1297 Currently, the only fixup is for the Geode machines using 1298 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1299 1300 Say Y if you want to enable the fixup. Currently, it's safe to 1301 enable this option even if you don't need it. 1302 Say N otherwise. 1303 1304config MICROCODE 1305 bool "CPU microcode loading support" 1306 default y 1307 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1308 select FW_LOADER 1309 ---help--- 1310 If you say Y here, you will be able to update the microcode on 1311 Intel and AMD processors. The Intel support is for the IA32 family, 1312 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1313 AMD support is for families 0x10 and later. You will obviously need 1314 the actual microcode binary data itself which is not shipped with 1315 the Linux kernel. 1316 1317 The preferred method to load microcode from a detached initrd is described 1318 in Documentation/x86/microcode.rst. For that you need to enable 1319 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1320 initrd for microcode blobs. 1321 1322 In addition, you can build the microcode into the kernel. For that you 1323 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1324 config option. 1325 1326config MICROCODE_INTEL 1327 bool "Intel microcode loading support" 1328 depends on MICROCODE 1329 default MICROCODE 1330 select FW_LOADER 1331 ---help--- 1332 This options enables microcode patch loading support for Intel 1333 processors. 1334 1335 For the current Intel microcode data package go to 1336 <https://downloadcenter.intel.com> and search for 1337 'Linux Processor Microcode Data File'. 1338 1339config MICROCODE_AMD 1340 bool "AMD microcode loading support" 1341 depends on MICROCODE 1342 select FW_LOADER 1343 ---help--- 1344 If you select this option, microcode patch loading support for AMD 1345 processors will be enabled. 1346 1347config MICROCODE_OLD_INTERFACE 1348 bool "Ancient loading interface (DEPRECATED)" 1349 default n 1350 depends on MICROCODE 1351 ---help--- 1352 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1353 which was used by userspace tools like iucode_tool and microcode.ctl. 1354 It is inadequate because it runs too late to be able to properly 1355 load microcode on a machine and it needs special tools. Instead, you 1356 should've switched to the early loading method with the initrd or 1357 builtin microcode by now: Documentation/x86/microcode.rst 1358 1359config X86_MSR 1360 tristate "/dev/cpu/*/msr - Model-specific register support" 1361 ---help--- 1362 This device gives privileged processes access to the x86 1363 Model-Specific Registers (MSRs). It is a character device with 1364 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1365 MSR accesses are directed to a specific CPU on multi-processor 1366 systems. 1367 1368config X86_CPUID 1369 tristate "/dev/cpu/*/cpuid - CPU information support" 1370 ---help--- 1371 This device gives processes access to the x86 CPUID instruction to 1372 be executed on a specific processor. It is a character device 1373 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1374 /dev/cpu/31/cpuid. 1375 1376choice 1377 prompt "High Memory Support" 1378 default HIGHMEM4G 1379 depends on X86_32 1380 1381config NOHIGHMEM 1382 bool "off" 1383 ---help--- 1384 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1385 However, the address space of 32-bit x86 processors is only 4 1386 Gigabytes large. That means that, if you have a large amount of 1387 physical memory, not all of it can be "permanently mapped" by the 1388 kernel. The physical memory that's not permanently mapped is called 1389 "high memory". 1390 1391 If you are compiling a kernel which will never run on a machine with 1392 more than 1 Gigabyte total physical RAM, answer "off" here (default 1393 choice and suitable for most users). This will result in a "3GB/1GB" 1394 split: 3GB are mapped so that each process sees a 3GB virtual memory 1395 space and the remaining part of the 4GB virtual memory space is used 1396 by the kernel to permanently map as much physical memory as 1397 possible. 1398 1399 If the machine has between 1 and 4 Gigabytes physical RAM, then 1400 answer "4GB" here. 1401 1402 If more than 4 Gigabytes is used then answer "64GB" here. This 1403 selection turns Intel PAE (Physical Address Extension) mode on. 1404 PAE implements 3-level paging on IA32 processors. PAE is fully 1405 supported by Linux, PAE mode is implemented on all recent Intel 1406 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1407 then the kernel will not boot on CPUs that don't support PAE! 1408 1409 The actual amount of total physical memory will either be 1410 auto detected or can be forced by using a kernel command line option 1411 such as "mem=256M". (Try "man bootparam" or see the documentation of 1412 your boot loader (lilo or loadlin) about how to pass options to the 1413 kernel at boot time.) 1414 1415 If unsure, say "off". 1416 1417config HIGHMEM4G 1418 bool "4GB" 1419 ---help--- 1420 Select this if you have a 32-bit processor and between 1 and 4 1421 gigabytes of physical RAM. 1422 1423config HIGHMEM64G 1424 bool "64GB" 1425 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1426 select X86_PAE 1427 ---help--- 1428 Select this if you have a 32-bit processor and more than 4 1429 gigabytes of physical RAM. 1430 1431endchoice 1432 1433choice 1434 prompt "Memory split" if EXPERT 1435 default VMSPLIT_3G 1436 depends on X86_32 1437 ---help--- 1438 Select the desired split between kernel and user memory. 1439 1440 If the address range available to the kernel is less than the 1441 physical memory installed, the remaining memory will be available 1442 as "high memory". Accessing high memory is a little more costly 1443 than low memory, as it needs to be mapped into the kernel first. 1444 Note that increasing the kernel address space limits the range 1445 available to user programs, making the address space there 1446 tighter. Selecting anything other than the default 3G/1G split 1447 will also likely make your kernel incompatible with binary-only 1448 kernel modules. 1449 1450 If you are not absolutely sure what you are doing, leave this 1451 option alone! 1452 1453 config VMSPLIT_3G 1454 bool "3G/1G user/kernel split" 1455 config VMSPLIT_3G_OPT 1456 depends on !X86_PAE 1457 bool "3G/1G user/kernel split (for full 1G low memory)" 1458 config VMSPLIT_2G 1459 bool "2G/2G user/kernel split" 1460 config VMSPLIT_2G_OPT 1461 depends on !X86_PAE 1462 bool "2G/2G user/kernel split (for full 2G low memory)" 1463 config VMSPLIT_1G 1464 bool "1G/3G user/kernel split" 1465endchoice 1466 1467config PAGE_OFFSET 1468 hex 1469 default 0xB0000000 if VMSPLIT_3G_OPT 1470 default 0x80000000 if VMSPLIT_2G 1471 default 0x78000000 if VMSPLIT_2G_OPT 1472 default 0x40000000 if VMSPLIT_1G 1473 default 0xC0000000 1474 depends on X86_32 1475 1476config HIGHMEM 1477 def_bool y 1478 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1479 1480config X86_PAE 1481 bool "PAE (Physical Address Extension) Support" 1482 depends on X86_32 && !HIGHMEM4G 1483 select PHYS_ADDR_T_64BIT 1484 select SWIOTLB 1485 ---help--- 1486 PAE is required for NX support, and furthermore enables 1487 larger swapspace support for non-overcommit purposes. It 1488 has the cost of more pagetable lookup overhead, and also 1489 consumes more pagetable space per process. 1490 1491config X86_5LEVEL 1492 bool "Enable 5-level page tables support" 1493 select DYNAMIC_MEMORY_LAYOUT 1494 select SPARSEMEM_VMEMMAP 1495 depends on X86_64 1496 ---help--- 1497 5-level paging enables access to larger address space: 1498 upto 128 PiB of virtual address space and 4 PiB of 1499 physical address space. 1500 1501 It will be supported by future Intel CPUs. 1502 1503 A kernel with the option enabled can be booted on machines that 1504 support 4- or 5-level paging. 1505 1506 See Documentation/x86/x86_64/5level-paging.rst for more 1507 information. 1508 1509 Say N if unsure. 1510 1511config X86_DIRECT_GBPAGES 1512 def_bool y 1513 depends on X86_64 1514 ---help--- 1515 Certain kernel features effectively disable kernel 1516 linear 1 GB mappings (even if the CPU otherwise 1517 supports them), so don't confuse the user by printing 1518 that we have them enabled. 1519 1520config X86_CPA_STATISTICS 1521 bool "Enable statistic for Change Page Attribute" 1522 depends on DEBUG_FS 1523 ---help--- 1524 Expose statistics about the Change Page Attribute mechanims, which 1525 helps to determine the effectiveness of preserving large and huge 1526 page mappings when mapping protections are changed. 1527 1528config ARCH_HAS_MEM_ENCRYPT 1529 def_bool y 1530 1531config AMD_MEM_ENCRYPT 1532 bool "AMD Secure Memory Encryption (SME) support" 1533 depends on X86_64 && CPU_SUP_AMD 1534 select DYNAMIC_PHYSICAL_MASK 1535 select ARCH_USE_MEMREMAP_PROT 1536 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1537 ---help--- 1538 Say yes to enable support for the encryption of system memory. 1539 This requires an AMD processor that supports Secure Memory 1540 Encryption (SME). 1541 1542config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1543 bool "Activate AMD Secure Memory Encryption (SME) by default" 1544 default y 1545 depends on AMD_MEM_ENCRYPT 1546 ---help--- 1547 Say yes to have system memory encrypted by default if running on 1548 an AMD processor that supports Secure Memory Encryption (SME). 1549 1550 If set to Y, then the encryption of system memory can be 1551 deactivated with the mem_encrypt=off command line option. 1552 1553 If set to N, then the encryption of system memory can be 1554 activated with the mem_encrypt=on command line option. 1555 1556# Common NUMA Features 1557config NUMA 1558 bool "Numa Memory Allocation and Scheduler Support" 1559 depends on SMP 1560 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1561 default y if X86_BIGSMP 1562 ---help--- 1563 Enable NUMA (Non Uniform Memory Access) support. 1564 1565 The kernel will try to allocate memory used by a CPU on the 1566 local memory controller of the CPU and add some more 1567 NUMA awareness to the kernel. 1568 1569 For 64-bit this is recommended if the system is Intel Core i7 1570 (or later), AMD Opteron, or EM64T NUMA. 1571 1572 For 32-bit this is only needed if you boot a 32-bit 1573 kernel on a 64-bit NUMA platform. 1574 1575 Otherwise, you should say N. 1576 1577config AMD_NUMA 1578 def_bool y 1579 prompt "Old style AMD Opteron NUMA detection" 1580 depends on X86_64 && NUMA && PCI 1581 ---help--- 1582 Enable AMD NUMA node topology detection. You should say Y here if 1583 you have a multi processor AMD system. This uses an old method to 1584 read the NUMA configuration directly from the builtin Northbridge 1585 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1586 which also takes priority if both are compiled in. 1587 1588config X86_64_ACPI_NUMA 1589 def_bool y 1590 prompt "ACPI NUMA detection" 1591 depends on X86_64 && NUMA && ACPI && PCI 1592 select ACPI_NUMA 1593 ---help--- 1594 Enable ACPI SRAT based node topology detection. 1595 1596# Some NUMA nodes have memory ranges that span 1597# other nodes. Even though a pfn is valid and 1598# between a node's start and end pfns, it may not 1599# reside on that node. See memmap_init_zone() 1600# for details. 1601config NODES_SPAN_OTHER_NODES 1602 def_bool y 1603 depends on X86_64_ACPI_NUMA 1604 1605config NUMA_EMU 1606 bool "NUMA emulation" 1607 depends on NUMA 1608 ---help--- 1609 Enable NUMA emulation. A flat machine will be split 1610 into virtual nodes when booted with "numa=fake=N", where N is the 1611 number of nodes. This is only useful for debugging. 1612 1613config NODES_SHIFT 1614 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1615 range 1 10 1616 default "10" if MAXSMP 1617 default "6" if X86_64 1618 default "3" 1619 depends on NEED_MULTIPLE_NODES 1620 ---help--- 1621 Specify the maximum number of NUMA Nodes available on the target 1622 system. Increases memory reserved to accommodate various tables. 1623 1624config ARCH_HAVE_MEMORY_PRESENT 1625 def_bool y 1626 depends on X86_32 && DISCONTIGMEM 1627 1628config ARCH_FLATMEM_ENABLE 1629 def_bool y 1630 depends on X86_32 && !NUMA 1631 1632config ARCH_DISCONTIGMEM_ENABLE 1633 def_bool n 1634 depends on NUMA && X86_32 1635 depends on BROKEN 1636 1637config ARCH_SPARSEMEM_ENABLE 1638 def_bool y 1639 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1640 select SPARSEMEM_STATIC if X86_32 1641 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1642 1643config ARCH_SPARSEMEM_DEFAULT 1644 def_bool X86_64 || (NUMA && X86_32) 1645 1646config ARCH_SELECT_MEMORY_MODEL 1647 def_bool y 1648 depends on ARCH_SPARSEMEM_ENABLE 1649 1650config ARCH_MEMORY_PROBE 1651 bool "Enable sysfs memory/probe interface" 1652 depends on X86_64 && MEMORY_HOTPLUG 1653 help 1654 This option enables a sysfs memory/probe interface for testing. 1655 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1656 If you are unsure how to answer this question, answer N. 1657 1658config ARCH_PROC_KCORE_TEXT 1659 def_bool y 1660 depends on X86_64 && PROC_KCORE 1661 1662config ILLEGAL_POINTER_VALUE 1663 hex 1664 default 0 if X86_32 1665 default 0xdead000000000000 if X86_64 1666 1667config X86_PMEM_LEGACY_DEVICE 1668 bool 1669 1670config X86_PMEM_LEGACY 1671 tristate "Support non-standard NVDIMMs and ADR protected memory" 1672 depends on PHYS_ADDR_T_64BIT 1673 depends on BLK_DEV 1674 select X86_PMEM_LEGACY_DEVICE 1675 select LIBNVDIMM 1676 help 1677 Treat memory marked using the non-standard e820 type of 12 as used 1678 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1679 The kernel will offer these regions to the 'pmem' driver so 1680 they can be used for persistent storage. 1681 1682 Say Y if unsure. 1683 1684config HIGHPTE 1685 bool "Allocate 3rd-level pagetables from highmem" 1686 depends on HIGHMEM 1687 ---help--- 1688 The VM uses one page table entry for each page of physical memory. 1689 For systems with a lot of RAM, this can be wasteful of precious 1690 low memory. Setting this option will put user-space page table 1691 entries in high memory. 1692 1693config X86_CHECK_BIOS_CORRUPTION 1694 bool "Check for low memory corruption" 1695 ---help--- 1696 Periodically check for memory corruption in low memory, which 1697 is suspected to be caused by BIOS. Even when enabled in the 1698 configuration, it is disabled at runtime. Enable it by 1699 setting "memory_corruption_check=1" on the kernel command 1700 line. By default it scans the low 64k of memory every 60 1701 seconds; see the memory_corruption_check_size and 1702 memory_corruption_check_period parameters in 1703 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1704 1705 When enabled with the default parameters, this option has 1706 almost no overhead, as it reserves a relatively small amount 1707 of memory and scans it infrequently. It both detects corruption 1708 and prevents it from affecting the running system. 1709 1710 It is, however, intended as a diagnostic tool; if repeatable 1711 BIOS-originated corruption always affects the same memory, 1712 you can use memmap= to prevent the kernel from using that 1713 memory. 1714 1715config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1716 bool "Set the default setting of memory_corruption_check" 1717 depends on X86_CHECK_BIOS_CORRUPTION 1718 default y 1719 ---help--- 1720 Set whether the default state of memory_corruption_check is 1721 on or off. 1722 1723config X86_RESERVE_LOW 1724 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1725 default 64 1726 range 4 640 1727 ---help--- 1728 Specify the amount of low memory to reserve for the BIOS. 1729 1730 The first page contains BIOS data structures that the kernel 1731 must not use, so that page must always be reserved. 1732 1733 By default we reserve the first 64K of physical RAM, as a 1734 number of BIOSes are known to corrupt that memory range 1735 during events such as suspend/resume or monitor cable 1736 insertion, so it must not be used by the kernel. 1737 1738 You can set this to 4 if you are absolutely sure that you 1739 trust the BIOS to get all its memory reservations and usages 1740 right. If you know your BIOS have problems beyond the 1741 default 64K area, you can set this to 640 to avoid using the 1742 entire low memory range. 1743 1744 If you have doubts about the BIOS (e.g. suspend/resume does 1745 not work or there's kernel crashes after certain hardware 1746 hotplug events) then you might want to enable 1747 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1748 typical corruption patterns. 1749 1750 Leave this to the default value of 64 if you are unsure. 1751 1752config MATH_EMULATION 1753 bool 1754 depends on MODIFY_LDT_SYSCALL 1755 prompt "Math emulation" if X86_32 1756 ---help--- 1757 Linux can emulate a math coprocessor (used for floating point 1758 operations) if you don't have one. 486DX and Pentium processors have 1759 a math coprocessor built in, 486SX and 386 do not, unless you added 1760 a 487DX or 387, respectively. (The messages during boot time can 1761 give you some hints here ["man dmesg"].) Everyone needs either a 1762 coprocessor or this emulation. 1763 1764 If you don't have a math coprocessor, you need to say Y here; if you 1765 say Y here even though you have a coprocessor, the coprocessor will 1766 be used nevertheless. (This behavior can be changed with the kernel 1767 command line option "no387", which comes handy if your coprocessor 1768 is broken. Try "man bootparam" or see the documentation of your boot 1769 loader (lilo or loadlin) about how to pass options to the kernel at 1770 boot time.) This means that it is a good idea to say Y here if you 1771 intend to use this kernel on different machines. 1772 1773 More information about the internals of the Linux math coprocessor 1774 emulation can be found in <file:arch/x86/math-emu/README>. 1775 1776 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1777 kernel, it won't hurt. 1778 1779config MTRR 1780 def_bool y 1781 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1782 ---help--- 1783 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1784 the Memory Type Range Registers (MTRRs) may be used to control 1785 processor access to memory ranges. This is most useful if you have 1786 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1787 allows bus write transfers to be combined into a larger transfer 1788 before bursting over the PCI/AGP bus. This can increase performance 1789 of image write operations 2.5 times or more. Saying Y here creates a 1790 /proc/mtrr file which may be used to manipulate your processor's 1791 MTRRs. Typically the X server should use this. 1792 1793 This code has a reasonably generic interface so that similar 1794 control registers on other processors can be easily supported 1795 as well: 1796 1797 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1798 Registers (ARRs) which provide a similar functionality to MTRRs. For 1799 these, the ARRs are used to emulate the MTRRs. 1800 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1801 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1802 write-combining. All of these processors are supported by this code 1803 and it makes sense to say Y here if you have one of them. 1804 1805 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1806 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1807 can lead to all sorts of problems, so it's good to say Y here. 1808 1809 You can safely say Y even if your machine doesn't have MTRRs, you'll 1810 just add about 9 KB to your kernel. 1811 1812 See <file:Documentation/x86/mtrr.rst> for more information. 1813 1814config MTRR_SANITIZER 1815 def_bool y 1816 prompt "MTRR cleanup support" 1817 depends on MTRR 1818 ---help--- 1819 Convert MTRR layout from continuous to discrete, so X drivers can 1820 add writeback entries. 1821 1822 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1823 The largest mtrr entry size for a continuous block can be set with 1824 mtrr_chunk_size. 1825 1826 If unsure, say Y. 1827 1828config MTRR_SANITIZER_ENABLE_DEFAULT 1829 int "MTRR cleanup enable value (0-1)" 1830 range 0 1 1831 default "0" 1832 depends on MTRR_SANITIZER 1833 ---help--- 1834 Enable mtrr cleanup default value 1835 1836config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1837 int "MTRR cleanup spare reg num (0-7)" 1838 range 0 7 1839 default "1" 1840 depends on MTRR_SANITIZER 1841 ---help--- 1842 mtrr cleanup spare entries default, it can be changed via 1843 mtrr_spare_reg_nr=N on the kernel command line. 1844 1845config X86_PAT 1846 def_bool y 1847 prompt "x86 PAT support" if EXPERT 1848 depends on MTRR 1849 ---help--- 1850 Use PAT attributes to setup page level cache control. 1851 1852 PATs are the modern equivalents of MTRRs and are much more 1853 flexible than MTRRs. 1854 1855 Say N here if you see bootup problems (boot crash, boot hang, 1856 spontaneous reboots) or a non-working video driver. 1857 1858 If unsure, say Y. 1859 1860config ARCH_USES_PG_UNCACHED 1861 def_bool y 1862 depends on X86_PAT 1863 1864config ARCH_RANDOM 1865 def_bool y 1866 prompt "x86 architectural random number generator" if EXPERT 1867 ---help--- 1868 Enable the x86 architectural RDRAND instruction 1869 (Intel Bull Mountain technology) to generate random numbers. 1870 If supported, this is a high bandwidth, cryptographically 1871 secure hardware random number generator. 1872 1873config X86_SMAP 1874 def_bool y 1875 prompt "Supervisor Mode Access Prevention" if EXPERT 1876 ---help--- 1877 Supervisor Mode Access Prevention (SMAP) is a security 1878 feature in newer Intel processors. There is a small 1879 performance cost if this enabled and turned on; there is 1880 also a small increase in the kernel size if this is enabled. 1881 1882 If unsure, say Y. 1883 1884config X86_INTEL_UMIP 1885 def_bool y 1886 depends on CPU_SUP_INTEL 1887 prompt "Intel User Mode Instruction Prevention" if EXPERT 1888 ---help--- 1889 The User Mode Instruction Prevention (UMIP) is a security 1890 feature in newer Intel processors. If enabled, a general 1891 protection fault is issued if the SGDT, SLDT, SIDT, SMSW 1892 or STR instructions are executed in user mode. These instructions 1893 unnecessarily expose information about the hardware state. 1894 1895 The vast majority of applications do not use these instructions. 1896 For the very few that do, software emulation is provided in 1897 specific cases in protected and virtual-8086 modes. Emulated 1898 results are dummy. 1899 1900config X86_INTEL_MPX 1901 prompt "Intel MPX (Memory Protection Extensions)" 1902 def_bool n 1903 # Note: only available in 64-bit mode due to VMA flags shortage 1904 depends on CPU_SUP_INTEL && X86_64 1905 select ARCH_USES_HIGH_VMA_FLAGS 1906 ---help--- 1907 MPX provides hardware features that can be used in 1908 conjunction with compiler-instrumented code to check 1909 memory references. It is designed to detect buffer 1910 overflow or underflow bugs. 1911 1912 This option enables running applications which are 1913 instrumented or otherwise use MPX. It does not use MPX 1914 itself inside the kernel or to protect the kernel 1915 against bad memory references. 1916 1917 Enabling this option will make the kernel larger: 1918 ~8k of kernel text and 36 bytes of data on a 64-bit 1919 defconfig. It adds a long to the 'mm_struct' which 1920 will increase the kernel memory overhead of each 1921 process and adds some branches to paths used during 1922 exec() and munmap(). 1923 1924 For details, see Documentation/x86/intel_mpx.rst 1925 1926 If unsure, say N. 1927 1928config X86_INTEL_MEMORY_PROTECTION_KEYS 1929 prompt "Intel Memory Protection Keys" 1930 def_bool y 1931 # Note: only available in 64-bit mode 1932 depends on CPU_SUP_INTEL && X86_64 1933 select ARCH_USES_HIGH_VMA_FLAGS 1934 select ARCH_HAS_PKEYS 1935 ---help--- 1936 Memory Protection Keys provides a mechanism for enforcing 1937 page-based protections, but without requiring modification of the 1938 page tables when an application changes protection domains. 1939 1940 For details, see Documentation/core-api/protection-keys.rst 1941 1942 If unsure, say y. 1943 1944config EFI 1945 bool "EFI runtime service support" 1946 depends on ACPI 1947 select UCS2_STRING 1948 select EFI_RUNTIME_WRAPPERS 1949 ---help--- 1950 This enables the kernel to use EFI runtime services that are 1951 available (such as the EFI variable services). 1952 1953 This option is only useful on systems that have EFI firmware. 1954 In addition, you should use the latest ELILO loader available 1955 at <http://elilo.sourceforge.net> in order to take advantage 1956 of EFI runtime services. However, even with this option, the 1957 resultant kernel should continue to boot on existing non-EFI 1958 platforms. 1959 1960config EFI_STUB 1961 bool "EFI stub support" 1962 depends on EFI && !X86_USE_3DNOW 1963 select RELOCATABLE 1964 ---help--- 1965 This kernel feature allows a bzImage to be loaded directly 1966 by EFI firmware without the use of a bootloader. 1967 1968 See Documentation/admin-guide/efi-stub.rst for more information. 1969 1970config EFI_MIXED 1971 bool "EFI mixed-mode support" 1972 depends on EFI_STUB && X86_64 1973 ---help--- 1974 Enabling this feature allows a 64-bit kernel to be booted 1975 on a 32-bit firmware, provided that your CPU supports 64-bit 1976 mode. 1977 1978 Note that it is not possible to boot a mixed-mode enabled 1979 kernel via the EFI boot stub - a bootloader that supports 1980 the EFI handover protocol must be used. 1981 1982 If unsure, say N. 1983 1984config SECCOMP 1985 def_bool y 1986 prompt "Enable seccomp to safely compute untrusted bytecode" 1987 ---help--- 1988 This kernel feature is useful for number crunching applications 1989 that may need to compute untrusted bytecode during their 1990 execution. By using pipes or other transports made available to 1991 the process as file descriptors supporting the read/write 1992 syscalls, it's possible to isolate those applications in 1993 their own address space using seccomp. Once seccomp is 1994 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 1995 and the task is only allowed to execute a few safe syscalls 1996 defined by each seccomp mode. 1997 1998 If unsure, say Y. Only embedded should say N here. 1999 2000source "kernel/Kconfig.hz" 2001 2002config KEXEC 2003 bool "kexec system call" 2004 select KEXEC_CORE 2005 ---help--- 2006 kexec is a system call that implements the ability to shutdown your 2007 current kernel, and to start another kernel. It is like a reboot 2008 but it is independent of the system firmware. And like a reboot 2009 you can start any kernel with it, not just Linux. 2010 2011 The name comes from the similarity to the exec system call. 2012 2013 It is an ongoing process to be certain the hardware in a machine 2014 is properly shutdown, so do not be surprised if this code does not 2015 initially work for you. As of this writing the exact hardware 2016 interface is strongly in flux, so no good recommendation can be 2017 made. 2018 2019config KEXEC_FILE 2020 bool "kexec file based system call" 2021 select KEXEC_CORE 2022 select BUILD_BIN2C 2023 depends on X86_64 2024 depends on CRYPTO=y 2025 depends on CRYPTO_SHA256=y 2026 ---help--- 2027 This is new version of kexec system call. This system call is 2028 file based and takes file descriptors as system call argument 2029 for kernel and initramfs as opposed to list of segments as 2030 accepted by previous system call. 2031 2032config ARCH_HAS_KEXEC_PURGATORY 2033 def_bool KEXEC_FILE 2034 2035config KEXEC_VERIFY_SIG 2036 bool "Verify kernel signature during kexec_file_load() syscall" 2037 depends on KEXEC_FILE 2038 ---help--- 2039 This option makes kernel signature verification mandatory for 2040 the kexec_file_load() syscall. 2041 2042 In addition to that option, you need to enable signature 2043 verification for the corresponding kernel image type being 2044 loaded in order for this to work. 2045 2046config KEXEC_BZIMAGE_VERIFY_SIG 2047 bool "Enable bzImage signature verification support" 2048 depends on KEXEC_VERIFY_SIG 2049 depends on SIGNED_PE_FILE_VERIFICATION 2050 select SYSTEM_TRUSTED_KEYRING 2051 ---help--- 2052 Enable bzImage signature verification support. 2053 2054config CRASH_DUMP 2055 bool "kernel crash dumps" 2056 depends on X86_64 || (X86_32 && HIGHMEM) 2057 ---help--- 2058 Generate crash dump after being started by kexec. 2059 This should be normally only set in special crash dump kernels 2060 which are loaded in the main kernel with kexec-tools into 2061 a specially reserved region and then later executed after 2062 a crash by kdump/kexec. The crash dump kernel must be compiled 2063 to a memory address not used by the main kernel or BIOS using 2064 PHYSICAL_START, or it must be built as a relocatable image 2065 (CONFIG_RELOCATABLE=y). 2066 For more details see Documentation/admin-guide/kdump/kdump.rst 2067 2068config KEXEC_JUMP 2069 bool "kexec jump" 2070 depends on KEXEC && HIBERNATION 2071 ---help--- 2072 Jump between original kernel and kexeced kernel and invoke 2073 code in physical address mode via KEXEC 2074 2075config PHYSICAL_START 2076 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2077 default "0x1000000" 2078 ---help--- 2079 This gives the physical address where the kernel is loaded. 2080 2081 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2082 bzImage will decompress itself to above physical address and 2083 run from there. Otherwise, bzImage will run from the address where 2084 it has been loaded by the boot loader and will ignore above physical 2085 address. 2086 2087 In normal kdump cases one does not have to set/change this option 2088 as now bzImage can be compiled as a completely relocatable image 2089 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2090 address. This option is mainly useful for the folks who don't want 2091 to use a bzImage for capturing the crash dump and want to use a 2092 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2093 to be specifically compiled to run from a specific memory area 2094 (normally a reserved region) and this option comes handy. 2095 2096 So if you are using bzImage for capturing the crash dump, 2097 leave the value here unchanged to 0x1000000 and set 2098 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2099 for capturing the crash dump change this value to start of 2100 the reserved region. In other words, it can be set based on 2101 the "X" value as specified in the "crashkernel=YM@XM" 2102 command line boot parameter passed to the panic-ed 2103 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2104 for more details about crash dumps. 2105 2106 Usage of bzImage for capturing the crash dump is recommended as 2107 one does not have to build two kernels. Same kernel can be used 2108 as production kernel and capture kernel. Above option should have 2109 gone away after relocatable bzImage support is introduced. But it 2110 is present because there are users out there who continue to use 2111 vmlinux for dump capture. This option should go away down the 2112 line. 2113 2114 Don't change this unless you know what you are doing. 2115 2116config RELOCATABLE 2117 bool "Build a relocatable kernel" 2118 default y 2119 ---help--- 2120 This builds a kernel image that retains relocation information 2121 so it can be loaded someplace besides the default 1MB. 2122 The relocations tend to make the kernel binary about 10% larger, 2123 but are discarded at runtime. 2124 2125 One use is for the kexec on panic case where the recovery kernel 2126 must live at a different physical address than the primary 2127 kernel. 2128 2129 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2130 it has been loaded at and the compile time physical address 2131 (CONFIG_PHYSICAL_START) is used as the minimum location. 2132 2133config RANDOMIZE_BASE 2134 bool "Randomize the address of the kernel image (KASLR)" 2135 depends on RELOCATABLE 2136 default y 2137 ---help--- 2138 In support of Kernel Address Space Layout Randomization (KASLR), 2139 this randomizes the physical address at which the kernel image 2140 is decompressed and the virtual address where the kernel 2141 image is mapped, as a security feature that deters exploit 2142 attempts relying on knowledge of the location of kernel 2143 code internals. 2144 2145 On 64-bit, the kernel physical and virtual addresses are 2146 randomized separately. The physical address will be anywhere 2147 between 16MB and the top of physical memory (up to 64TB). The 2148 virtual address will be randomized from 16MB up to 1GB (9 bits 2149 of entropy). Note that this also reduces the memory space 2150 available to kernel modules from 1.5GB to 1GB. 2151 2152 On 32-bit, the kernel physical and virtual addresses are 2153 randomized together. They will be randomized from 16MB up to 2154 512MB (8 bits of entropy). 2155 2156 Entropy is generated using the RDRAND instruction if it is 2157 supported. If RDTSC is supported, its value is mixed into 2158 the entropy pool as well. If neither RDRAND nor RDTSC are 2159 supported, then entropy is read from the i8254 timer. The 2160 usable entropy is limited by the kernel being built using 2161 2GB addressing, and that PHYSICAL_ALIGN must be at a 2162 minimum of 2MB. As a result, only 10 bits of entropy are 2163 theoretically possible, but the implementations are further 2164 limited due to memory layouts. 2165 2166 If unsure, say Y. 2167 2168# Relocation on x86 needs some additional build support 2169config X86_NEED_RELOCS 2170 def_bool y 2171 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2172 2173config PHYSICAL_ALIGN 2174 hex "Alignment value to which kernel should be aligned" 2175 default "0x200000" 2176 range 0x2000 0x1000000 if X86_32 2177 range 0x200000 0x1000000 if X86_64 2178 ---help--- 2179 This value puts the alignment restrictions on physical address 2180 where kernel is loaded and run from. Kernel is compiled for an 2181 address which meets above alignment restriction. 2182 2183 If bootloader loads the kernel at a non-aligned address and 2184 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2185 address aligned to above value and run from there. 2186 2187 If bootloader loads the kernel at a non-aligned address and 2188 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2189 load address and decompress itself to the address it has been 2190 compiled for and run from there. The address for which kernel is 2191 compiled already meets above alignment restrictions. Hence the 2192 end result is that kernel runs from a physical address meeting 2193 above alignment restrictions. 2194 2195 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2196 this value must be a multiple of 0x200000. 2197 2198 Don't change this unless you know what you are doing. 2199 2200config DYNAMIC_MEMORY_LAYOUT 2201 bool 2202 ---help--- 2203 This option makes base addresses of vmalloc and vmemmap as well as 2204 __PAGE_OFFSET movable during boot. 2205 2206config RANDOMIZE_MEMORY 2207 bool "Randomize the kernel memory sections" 2208 depends on X86_64 2209 depends on RANDOMIZE_BASE 2210 select DYNAMIC_MEMORY_LAYOUT 2211 default RANDOMIZE_BASE 2212 ---help--- 2213 Randomizes the base virtual address of kernel memory sections 2214 (physical memory mapping, vmalloc & vmemmap). This security feature 2215 makes exploits relying on predictable memory locations less reliable. 2216 2217 The order of allocations remains unchanged. Entropy is generated in 2218 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2219 configuration have in average 30,000 different possible virtual 2220 addresses for each memory section. 2221 2222 If unsure, say Y. 2223 2224config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2225 hex "Physical memory mapping padding" if EXPERT 2226 depends on RANDOMIZE_MEMORY 2227 default "0xa" if MEMORY_HOTPLUG 2228 default "0x0" 2229 range 0x1 0x40 if MEMORY_HOTPLUG 2230 range 0x0 0x40 2231 ---help--- 2232 Define the padding in terabytes added to the existing physical 2233 memory size during kernel memory randomization. It is useful 2234 for memory hotplug support but reduces the entropy available for 2235 address randomization. 2236 2237 If unsure, leave at the default value. 2238 2239config HOTPLUG_CPU 2240 def_bool y 2241 depends on SMP 2242 2243config BOOTPARAM_HOTPLUG_CPU0 2244 bool "Set default setting of cpu0_hotpluggable" 2245 depends on HOTPLUG_CPU 2246 ---help--- 2247 Set whether default state of cpu0_hotpluggable is on or off. 2248 2249 Say Y here to enable CPU0 hotplug by default. If this switch 2250 is turned on, there is no need to give cpu0_hotplug kernel 2251 parameter and the CPU0 hotplug feature is enabled by default. 2252 2253 Please note: there are two known CPU0 dependencies if you want 2254 to enable the CPU0 hotplug feature either by this switch or by 2255 cpu0_hotplug kernel parameter. 2256 2257 First, resume from hibernate or suspend always starts from CPU0. 2258 So hibernate and suspend are prevented if CPU0 is offline. 2259 2260 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2261 offline if any interrupt can not migrate out of CPU0. There may 2262 be other CPU0 dependencies. 2263 2264 Please make sure the dependencies are under your control before 2265 you enable this feature. 2266 2267 Say N if you don't want to enable CPU0 hotplug feature by default. 2268 You still can enable the CPU0 hotplug feature at boot by kernel 2269 parameter cpu0_hotplug. 2270 2271config DEBUG_HOTPLUG_CPU0 2272 def_bool n 2273 prompt "Debug CPU0 hotplug" 2274 depends on HOTPLUG_CPU 2275 ---help--- 2276 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2277 soon as possible and boots up userspace with CPU0 offlined. User 2278 can online CPU0 back after boot time. 2279 2280 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2281 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2282 compilation or giving cpu0_hotplug kernel parameter at boot. 2283 2284 If unsure, say N. 2285 2286config COMPAT_VDSO 2287 def_bool n 2288 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2289 depends on COMPAT_32 2290 ---help--- 2291 Certain buggy versions of glibc will crash if they are 2292 presented with a 32-bit vDSO that is not mapped at the address 2293 indicated in its segment table. 2294 2295 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2296 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2297 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2298 the only released version with the bug, but OpenSUSE 9 2299 contains a buggy "glibc 2.3.2". 2300 2301 The symptom of the bug is that everything crashes on startup, saying: 2302 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2303 2304 Saying Y here changes the default value of the vdso32 boot 2305 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2306 This works around the glibc bug but hurts performance. 2307 2308 If unsure, say N: if you are compiling your own kernel, you 2309 are unlikely to be using a buggy version of glibc. 2310 2311choice 2312 prompt "vsyscall table for legacy applications" 2313 depends on X86_64 2314 default LEGACY_VSYSCALL_XONLY 2315 help 2316 Legacy user code that does not know how to find the vDSO expects 2317 to be able to issue three syscalls by calling fixed addresses in 2318 kernel space. Since this location is not randomized with ASLR, 2319 it can be used to assist security vulnerability exploitation. 2320 2321 This setting can be changed at boot time via the kernel command 2322 line parameter vsyscall=[emulate|xonly|none]. 2323 2324 On a system with recent enough glibc (2.14 or newer) and no 2325 static binaries, you can say None without a performance penalty 2326 to improve security. 2327 2328 If unsure, select "Emulate execution only". 2329 2330 config LEGACY_VSYSCALL_EMULATE 2331 bool "Full emulation" 2332 help 2333 The kernel traps and emulates calls into the fixed vsyscall 2334 address mapping. This makes the mapping non-executable, but 2335 it still contains readable known contents, which could be 2336 used in certain rare security vulnerability exploits. This 2337 configuration is recommended when using legacy userspace 2338 that still uses vsyscalls along with legacy binary 2339 instrumentation tools that require code to be readable. 2340 2341 An example of this type of legacy userspace is running 2342 Pin on an old binary that still uses vsyscalls. 2343 2344 config LEGACY_VSYSCALL_XONLY 2345 bool "Emulate execution only" 2346 help 2347 The kernel traps and emulates calls into the fixed vsyscall 2348 address mapping and does not allow reads. This 2349 configuration is recommended when userspace might use the 2350 legacy vsyscall area but support for legacy binary 2351 instrumentation of legacy code is not needed. It mitigates 2352 certain uses of the vsyscall area as an ASLR-bypassing 2353 buffer. 2354 2355 config LEGACY_VSYSCALL_NONE 2356 bool "None" 2357 help 2358 There will be no vsyscall mapping at all. This will 2359 eliminate any risk of ASLR bypass due to the vsyscall 2360 fixed address mapping. Attempts to use the vsyscalls 2361 will be reported to dmesg, so that either old or 2362 malicious userspace programs can be identified. 2363 2364endchoice 2365 2366config CMDLINE_BOOL 2367 bool "Built-in kernel command line" 2368 ---help--- 2369 Allow for specifying boot arguments to the kernel at 2370 build time. On some systems (e.g. embedded ones), it is 2371 necessary or convenient to provide some or all of the 2372 kernel boot arguments with the kernel itself (that is, 2373 to not rely on the boot loader to provide them.) 2374 2375 To compile command line arguments into the kernel, 2376 set this option to 'Y', then fill in the 2377 boot arguments in CONFIG_CMDLINE. 2378 2379 Systems with fully functional boot loaders (i.e. non-embedded) 2380 should leave this option set to 'N'. 2381 2382config CMDLINE 2383 string "Built-in kernel command string" 2384 depends on CMDLINE_BOOL 2385 default "" 2386 ---help--- 2387 Enter arguments here that should be compiled into the kernel 2388 image and used at boot time. If the boot loader provides a 2389 command line at boot time, it is appended to this string to 2390 form the full kernel command line, when the system boots. 2391 2392 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2393 change this behavior. 2394 2395 In most cases, the command line (whether built-in or provided 2396 by the boot loader) should specify the device for the root 2397 file system. 2398 2399config CMDLINE_OVERRIDE 2400 bool "Built-in command line overrides boot loader arguments" 2401 depends on CMDLINE_BOOL 2402 ---help--- 2403 Set this option to 'Y' to have the kernel ignore the boot loader 2404 command line, and use ONLY the built-in command line. 2405 2406 This is used to work around broken boot loaders. This should 2407 be set to 'N' under normal conditions. 2408 2409config MODIFY_LDT_SYSCALL 2410 bool "Enable the LDT (local descriptor table)" if EXPERT 2411 default y 2412 ---help--- 2413 Linux can allow user programs to install a per-process x86 2414 Local Descriptor Table (LDT) using the modify_ldt(2) system 2415 call. This is required to run 16-bit or segmented code such as 2416 DOSEMU or some Wine programs. It is also used by some very old 2417 threading libraries. 2418 2419 Enabling this feature adds a small amount of overhead to 2420 context switches and increases the low-level kernel attack 2421 surface. Disabling it removes the modify_ldt(2) system call. 2422 2423 Saying 'N' here may make sense for embedded or server kernels. 2424 2425source "kernel/livepatch/Kconfig" 2426 2427endmenu 2428 2429config ARCH_HAS_ADD_PAGES 2430 def_bool y 2431 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2432 2433config ARCH_ENABLE_MEMORY_HOTPLUG 2434 def_bool y 2435 depends on X86_64 || (X86_32 && HIGHMEM) 2436 2437config ARCH_ENABLE_MEMORY_HOTREMOVE 2438 def_bool y 2439 depends on MEMORY_HOTPLUG 2440 2441config USE_PERCPU_NUMA_NODE_ID 2442 def_bool y 2443 depends on NUMA 2444 2445config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2446 def_bool y 2447 depends on X86_64 || X86_PAE 2448 2449config ARCH_ENABLE_HUGEPAGE_MIGRATION 2450 def_bool y 2451 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2452 2453config ARCH_ENABLE_THP_MIGRATION 2454 def_bool y 2455 depends on X86_64 && TRANSPARENT_HUGEPAGE 2456 2457menu "Power management and ACPI options" 2458 2459config ARCH_HIBERNATION_HEADER 2460 def_bool y 2461 depends on HIBERNATION 2462 2463source "kernel/power/Kconfig" 2464 2465source "drivers/acpi/Kconfig" 2466 2467source "drivers/sfi/Kconfig" 2468 2469config X86_APM_BOOT 2470 def_bool y 2471 depends on APM 2472 2473menuconfig APM 2474 tristate "APM (Advanced Power Management) BIOS support" 2475 depends on X86_32 && PM_SLEEP 2476 ---help--- 2477 APM is a BIOS specification for saving power using several different 2478 techniques. This is mostly useful for battery powered laptops with 2479 APM compliant BIOSes. If you say Y here, the system time will be 2480 reset after a RESUME operation, the /proc/apm device will provide 2481 battery status information, and user-space programs will receive 2482 notification of APM "events" (e.g. battery status change). 2483 2484 If you select "Y" here, you can disable actual use of the APM 2485 BIOS by passing the "apm=off" option to the kernel at boot time. 2486 2487 Note that the APM support is almost completely disabled for 2488 machines with more than one CPU. 2489 2490 In order to use APM, you will need supporting software. For location 2491 and more information, read <file:Documentation/power/apm-acpi.rst> 2492 and the Battery Powered Linux mini-HOWTO, available from 2493 <http://www.tldp.org/docs.html#howto>. 2494 2495 This driver does not spin down disk drives (see the hdparm(8) 2496 manpage ("man 8 hdparm") for that), and it doesn't turn off 2497 VESA-compliant "green" monitors. 2498 2499 This driver does not support the TI 4000M TravelMate and the ACER 2500 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2501 desktop machines also don't have compliant BIOSes, and this driver 2502 may cause those machines to panic during the boot phase. 2503 2504 Generally, if you don't have a battery in your machine, there isn't 2505 much point in using this driver and you should say N. If you get 2506 random kernel OOPSes or reboots that don't seem to be related to 2507 anything, try disabling/enabling this option (or disabling/enabling 2508 APM in your BIOS). 2509 2510 Some other things you should try when experiencing seemingly random, 2511 "weird" problems: 2512 2513 1) make sure that you have enough swap space and that it is 2514 enabled. 2515 2) pass the "no-hlt" option to the kernel 2516 3) switch on floating point emulation in the kernel and pass 2517 the "no387" option to the kernel 2518 4) pass the "floppy=nodma" option to the kernel 2519 5) pass the "mem=4M" option to the kernel (thereby disabling 2520 all but the first 4 MB of RAM) 2521 6) make sure that the CPU is not over clocked. 2522 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2523 8) disable the cache from your BIOS settings 2524 9) install a fan for the video card or exchange video RAM 2525 10) install a better fan for the CPU 2526 11) exchange RAM chips 2527 12) exchange the motherboard. 2528 2529 To compile this driver as a module, choose M here: the 2530 module will be called apm. 2531 2532if APM 2533 2534config APM_IGNORE_USER_SUSPEND 2535 bool "Ignore USER SUSPEND" 2536 ---help--- 2537 This option will ignore USER SUSPEND requests. On machines with a 2538 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2539 series notebooks, it is necessary to say Y because of a BIOS bug. 2540 2541config APM_DO_ENABLE 2542 bool "Enable PM at boot time" 2543 ---help--- 2544 Enable APM features at boot time. From page 36 of the APM BIOS 2545 specification: "When disabled, the APM BIOS does not automatically 2546 power manage devices, enter the Standby State, enter the Suspend 2547 State, or take power saving steps in response to CPU Idle calls." 2548 This driver will make CPU Idle calls when Linux is idle (unless this 2549 feature is turned off -- see "Do CPU IDLE calls", below). This 2550 should always save battery power, but more complicated APM features 2551 will be dependent on your BIOS implementation. You may need to turn 2552 this option off if your computer hangs at boot time when using APM 2553 support, or if it beeps continuously instead of suspending. Turn 2554 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2555 T400CDT. This is off by default since most machines do fine without 2556 this feature. 2557 2558config APM_CPU_IDLE 2559 depends on CPU_IDLE 2560 bool "Make CPU Idle calls when idle" 2561 ---help--- 2562 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2563 On some machines, this can activate improved power savings, such as 2564 a slowed CPU clock rate, when the machine is idle. These idle calls 2565 are made after the idle loop has run for some length of time (e.g., 2566 333 mS). On some machines, this will cause a hang at boot time or 2567 whenever the CPU becomes idle. (On machines with more than one CPU, 2568 this option does nothing.) 2569 2570config APM_DISPLAY_BLANK 2571 bool "Enable console blanking using APM" 2572 ---help--- 2573 Enable console blanking using the APM. Some laptops can use this to 2574 turn off the LCD backlight when the screen blanker of the Linux 2575 virtual console blanks the screen. Note that this is only used by 2576 the virtual console screen blanker, and won't turn off the backlight 2577 when using the X Window system. This also doesn't have anything to 2578 do with your VESA-compliant power-saving monitor. Further, this 2579 option doesn't work for all laptops -- it might not turn off your 2580 backlight at all, or it might print a lot of errors to the console, 2581 especially if you are using gpm. 2582 2583config APM_ALLOW_INTS 2584 bool "Allow interrupts during APM BIOS calls" 2585 ---help--- 2586 Normally we disable external interrupts while we are making calls to 2587 the APM BIOS as a measure to lessen the effects of a badly behaving 2588 BIOS implementation. The BIOS should reenable interrupts if it 2589 needs to. Unfortunately, some BIOSes do not -- especially those in 2590 many of the newer IBM Thinkpads. If you experience hangs when you 2591 suspend, try setting this to Y. Otherwise, say N. 2592 2593endif # APM 2594 2595source "drivers/cpufreq/Kconfig" 2596 2597source "drivers/cpuidle/Kconfig" 2598 2599source "drivers/idle/Kconfig" 2600 2601endmenu 2602 2603 2604menu "Bus options (PCI etc.)" 2605 2606choice 2607 prompt "PCI access mode" 2608 depends on X86_32 && PCI 2609 default PCI_GOANY 2610 ---help--- 2611 On PCI systems, the BIOS can be used to detect the PCI devices and 2612 determine their configuration. However, some old PCI motherboards 2613 have BIOS bugs and may crash if this is done. Also, some embedded 2614 PCI-based systems don't have any BIOS at all. Linux can also try to 2615 detect the PCI hardware directly without using the BIOS. 2616 2617 With this option, you can specify how Linux should detect the 2618 PCI devices. If you choose "BIOS", the BIOS will be used, 2619 if you choose "Direct", the BIOS won't be used, and if you 2620 choose "MMConfig", then PCI Express MMCONFIG will be used. 2621 If you choose "Any", the kernel will try MMCONFIG, then the 2622 direct access method and falls back to the BIOS if that doesn't 2623 work. If unsure, go with the default, which is "Any". 2624 2625config PCI_GOBIOS 2626 bool "BIOS" 2627 2628config PCI_GOMMCONFIG 2629 bool "MMConfig" 2630 2631config PCI_GODIRECT 2632 bool "Direct" 2633 2634config PCI_GOOLPC 2635 bool "OLPC XO-1" 2636 depends on OLPC 2637 2638config PCI_GOANY 2639 bool "Any" 2640 2641endchoice 2642 2643config PCI_BIOS 2644 def_bool y 2645 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2646 2647# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2648config PCI_DIRECT 2649 def_bool y 2650 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2651 2652config PCI_MMCONFIG 2653 bool "Support mmconfig PCI config space access" if X86_64 2654 default y 2655 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2656 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2657 2658config PCI_OLPC 2659 def_bool y 2660 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2661 2662config PCI_XEN 2663 def_bool y 2664 depends on PCI && XEN 2665 select SWIOTLB_XEN 2666 2667config MMCONF_FAM10H 2668 def_bool y 2669 depends on X86_64 && PCI_MMCONFIG && ACPI 2670 2671config PCI_CNB20LE_QUIRK 2672 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2673 depends on PCI 2674 help 2675 Read the PCI windows out of the CNB20LE host bridge. This allows 2676 PCI hotplug to work on systems with the CNB20LE chipset which do 2677 not have ACPI. 2678 2679 There's no public spec for this chipset, and this functionality 2680 is known to be incomplete. 2681 2682 You should say N unless you know you need this. 2683 2684config ISA_BUS 2685 bool "ISA bus support on modern systems" if EXPERT 2686 help 2687 Expose ISA bus device drivers and options available for selection and 2688 configuration. Enable this option if your target machine has an ISA 2689 bus. ISA is an older system, displaced by PCI and newer bus 2690 architectures -- if your target machine is modern, it probably does 2691 not have an ISA bus. 2692 2693 If unsure, say N. 2694 2695# x86_64 have no ISA slots, but can have ISA-style DMA. 2696config ISA_DMA_API 2697 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2698 default y 2699 help 2700 Enables ISA-style DMA support for devices requiring such controllers. 2701 If unsure, say Y. 2702 2703if X86_32 2704 2705config ISA 2706 bool "ISA support" 2707 ---help--- 2708 Find out whether you have ISA slots on your motherboard. ISA is the 2709 name of a bus system, i.e. the way the CPU talks to the other stuff 2710 inside your box. Other bus systems are PCI, EISA, MicroChannel 2711 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2712 newer boards don't support it. If you have ISA, say Y, otherwise N. 2713 2714config SCx200 2715 tristate "NatSemi SCx200 support" 2716 ---help--- 2717 This provides basic support for National Semiconductor's 2718 (now AMD's) Geode processors. The driver probes for the 2719 PCI-IDs of several on-chip devices, so its a good dependency 2720 for other scx200_* drivers. 2721 2722 If compiled as a module, the driver is named scx200. 2723 2724config SCx200HR_TIMER 2725 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2726 depends on SCx200 2727 default y 2728 ---help--- 2729 This driver provides a clocksource built upon the on-chip 2730 27MHz high-resolution timer. Its also a workaround for 2731 NSC Geode SC-1100's buggy TSC, which loses time when the 2732 processor goes idle (as is done by the scheduler). The 2733 other workaround is idle=poll boot option. 2734 2735config OLPC 2736 bool "One Laptop Per Child support" 2737 depends on !X86_PAE 2738 select GPIOLIB 2739 select OF 2740 select OF_PROMTREE 2741 select IRQ_DOMAIN 2742 select OLPC_EC 2743 ---help--- 2744 Add support for detecting the unique features of the OLPC 2745 XO hardware. 2746 2747config OLPC_XO1_PM 2748 bool "OLPC XO-1 Power Management" 2749 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2750 ---help--- 2751 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2752 2753config OLPC_XO1_RTC 2754 bool "OLPC XO-1 Real Time Clock" 2755 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2756 ---help--- 2757 Add support for the XO-1 real time clock, which can be used as a 2758 programmable wakeup source. 2759 2760config OLPC_XO1_SCI 2761 bool "OLPC XO-1 SCI extras" 2762 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2763 depends on INPUT=y 2764 select POWER_SUPPLY 2765 ---help--- 2766 Add support for SCI-based features of the OLPC XO-1 laptop: 2767 - EC-driven system wakeups 2768 - Power button 2769 - Ebook switch 2770 - Lid switch 2771 - AC adapter status updates 2772 - Battery status updates 2773 2774config OLPC_XO15_SCI 2775 bool "OLPC XO-1.5 SCI extras" 2776 depends on OLPC && ACPI 2777 select POWER_SUPPLY 2778 ---help--- 2779 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2780 - EC-driven system wakeups 2781 - AC adapter status updates 2782 - Battery status updates 2783 2784config ALIX 2785 bool "PCEngines ALIX System Support (LED setup)" 2786 select GPIOLIB 2787 ---help--- 2788 This option enables system support for the PCEngines ALIX. 2789 At present this just sets up LEDs for GPIO control on 2790 ALIX2/3/6 boards. However, other system specific setup should 2791 get added here. 2792 2793 Note: You must still enable the drivers for GPIO and LED support 2794 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2795 2796 Note: You have to set alix.force=1 for boards with Award BIOS. 2797 2798config NET5501 2799 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2800 select GPIOLIB 2801 ---help--- 2802 This option enables system support for the Soekris Engineering net5501. 2803 2804config GEOS 2805 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2806 select GPIOLIB 2807 depends on DMI 2808 ---help--- 2809 This option enables system support for the Traverse Technologies GEOS. 2810 2811config TS5500 2812 bool "Technologic Systems TS-5500 platform support" 2813 depends on MELAN 2814 select CHECK_SIGNATURE 2815 select NEW_LEDS 2816 select LEDS_CLASS 2817 ---help--- 2818 This option enables system support for the Technologic Systems TS-5500. 2819 2820endif # X86_32 2821 2822config AMD_NB 2823 def_bool y 2824 depends on CPU_SUP_AMD && PCI 2825 2826config X86_SYSFB 2827 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2828 help 2829 Firmwares often provide initial graphics framebuffers so the BIOS, 2830 bootloader or kernel can show basic video-output during boot for 2831 user-guidance and debugging. Historically, x86 used the VESA BIOS 2832 Extensions and EFI-framebuffers for this, which are mostly limited 2833 to x86. 2834 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2835 framebuffers so the new generic system-framebuffer drivers can be 2836 used on x86. If the framebuffer is not compatible with the generic 2837 modes, it is advertised as fallback platform framebuffer so legacy 2838 drivers like efifb, vesafb and uvesafb can pick it up. 2839 If this option is not selected, all system framebuffers are always 2840 marked as fallback platform framebuffers as usual. 2841 2842 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2843 not be able to pick up generic system framebuffers if this option 2844 is selected. You are highly encouraged to enable simplefb as 2845 replacement if you select this option. simplefb can correctly deal 2846 with generic system framebuffers. But you should still keep vesafb 2847 and others enabled as fallback if a system framebuffer is 2848 incompatible with simplefb. 2849 2850 If unsure, say Y. 2851 2852endmenu 2853 2854 2855menu "Binary Emulations" 2856 2857config IA32_EMULATION 2858 bool "IA32 Emulation" 2859 depends on X86_64 2860 select ARCH_WANT_OLD_COMPAT_IPC 2861 select BINFMT_ELF 2862 select COMPAT_BINFMT_ELF 2863 select COMPAT_OLD_SIGACTION 2864 ---help--- 2865 Include code to run legacy 32-bit programs under a 2866 64-bit kernel. You should likely turn this on, unless you're 2867 100% sure that you don't have any 32-bit programs left. 2868 2869config IA32_AOUT 2870 tristate "IA32 a.out support" 2871 depends on IA32_EMULATION 2872 depends on BROKEN 2873 ---help--- 2874 Support old a.out binaries in the 32bit emulation. 2875 2876config X86_X32 2877 bool "x32 ABI for 64-bit mode" 2878 depends on X86_64 2879 ---help--- 2880 Include code to run binaries for the x32 native 32-bit ABI 2881 for 64-bit processors. An x32 process gets access to the 2882 full 64-bit register file and wide data path while leaving 2883 pointers at 32 bits for smaller memory footprint. 2884 2885 You will need a recent binutils (2.22 or later) with 2886 elf32_x86_64 support enabled to compile a kernel with this 2887 option set. 2888 2889config COMPAT_32 2890 def_bool y 2891 depends on IA32_EMULATION || X86_32 2892 select HAVE_UID16 2893 select OLD_SIGSUSPEND3 2894 2895config COMPAT 2896 def_bool y 2897 depends on IA32_EMULATION || X86_X32 2898 2899if COMPAT 2900config COMPAT_FOR_U64_ALIGNMENT 2901 def_bool y 2902 2903config SYSVIPC_COMPAT 2904 def_bool y 2905 depends on SYSVIPC 2906endif 2907 2908endmenu 2909 2910 2911config HAVE_ATOMIC_IOMAP 2912 def_bool y 2913 depends on X86_32 2914 2915config X86_DEV_DMA_OPS 2916 bool 2917 2918source "drivers/firmware/Kconfig" 2919 2920source "arch/x86/kvm/Kconfig" 2921