1# SPDX-License-Identifier: GPL-2.0 2# Select 32 or 64 bit 3config 64BIT 4 bool "64-bit kernel" if "$(ARCH)" = "x86" 5 default "$(ARCH)" != "i386" 6 ---help--- 7 Say yes to build a 64-bit kernel - formerly known as x86_64 8 Say no to build a 32-bit kernel - formerly known as i386 9 10config X86_32 11 def_bool y 12 depends on !64BIT 13 # Options that are inherently 32-bit kernel only: 14 select ARCH_WANT_IPC_PARSE_VERSION 15 select CLKSRC_I8253 16 select CLONE_BACKWARDS 17 select HAVE_DEBUG_STACKOVERFLOW 18 select MODULES_USE_ELF_REL 19 select OLD_SIGACTION 20 select GENERIC_VDSO_32 21 22config X86_64 23 def_bool y 24 depends on 64BIT 25 # Options that are inherently 64-bit kernel only: 26 select ARCH_HAS_GIGANTIC_PAGE 27 select ARCH_SUPPORTS_INT128 28 select ARCH_USE_CMPXCHG_LOCKREF 29 select HAVE_ARCH_SOFT_DIRTY 30 select MODULES_USE_ELF_RELA 31 select NEED_DMA_MAP_STATE 32 select SWIOTLB 33 select ARCH_HAS_SYSCALL_WRAPPER 34 35config FORCE_DYNAMIC_FTRACE 36 def_bool y 37 depends on X86_32 38 depends on FUNCTION_TRACER 39 select DYNAMIC_FTRACE 40 help 41 We keep the static function tracing (!DYNAMIC_FTRACE) around 42 in order to test the non static function tracing in the 43 generic code, as other architectures still use it. But we 44 only need to keep it around for x86_64. No need to keep it 45 for x86_32. For x86_32, force DYNAMIC_FTRACE. 46# 47# Arch settings 48# 49# ( Note that options that are marked 'if X86_64' could in principle be 50# ported to 32-bit as well. ) 51# 52config X86 53 def_bool y 54 # 55 # Note: keep this list sorted alphabetically 56 # 57 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 58 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 59 select ARCH_32BIT_OFF_T if X86_32 60 select ARCH_CLOCKSOURCE_DATA 61 select ARCH_CLOCKSOURCE_INIT 62 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 63 select ARCH_HAS_DEBUG_VIRTUAL 64 select ARCH_HAS_DEVMEM_IS_ALLOWED 65 select ARCH_HAS_ELF_RANDOMIZE 66 select ARCH_HAS_FAST_MULTIPLIER 67 select ARCH_HAS_FILTER_PGPROT 68 select ARCH_HAS_FORTIFY_SOURCE 69 select ARCH_HAS_GCOV_PROFILE_ALL 70 select ARCH_HAS_KCOV if X86_64 71 select ARCH_HAS_MEM_ENCRYPT 72 select ARCH_HAS_MEMBARRIER_SYNC_CORE 73 select ARCH_HAS_PMEM_API if X86_64 74 select ARCH_HAS_PTE_DEVMAP if X86_64 75 select ARCH_HAS_PTE_SPECIAL 76 select ARCH_HAS_REFCOUNT 77 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 78 select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE 79 select ARCH_HAS_SET_MEMORY 80 select ARCH_HAS_SET_DIRECT_MAP 81 select ARCH_HAS_STRICT_KERNEL_RWX 82 select ARCH_HAS_STRICT_MODULE_RWX 83 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 84 select ARCH_HAS_UBSAN_SANITIZE_ALL 85 select ARCH_HAVE_NMI_SAFE_CMPXCHG 86 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 87 select ARCH_MIGHT_HAVE_PC_PARPORT 88 select ARCH_MIGHT_HAVE_PC_SERIO 89 select ARCH_STACKWALK 90 select ARCH_SUPPORTS_ACPI 91 select ARCH_SUPPORTS_ATOMIC_RMW 92 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 93 select ARCH_USE_BUILTIN_BSWAP 94 select ARCH_USE_QUEUED_RWLOCKS 95 select ARCH_USE_QUEUED_SPINLOCKS 96 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 97 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 98 select ARCH_WANT_HUGE_PMD_SHARE 99 select ARCH_WANTS_THP_SWAP if X86_64 100 select BUILDTIME_EXTABLE_SORT 101 select CLKEVT_I8253 102 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 103 select CLOCKSOURCE_WATCHDOG 104 select DCACHE_WORD_ACCESS 105 select EDAC_ATOMIC_SCRUB 106 select EDAC_SUPPORT 107 select GENERIC_CLOCKEVENTS 108 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 109 select GENERIC_CLOCKEVENTS_MIN_ADJUST 110 select GENERIC_CMOS_UPDATE 111 select GENERIC_CPU_AUTOPROBE 112 select GENERIC_CPU_VULNERABILITIES 113 select GENERIC_EARLY_IOREMAP 114 select GENERIC_FIND_FIRST_BIT 115 select GENERIC_IOMAP 116 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 117 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 118 select GENERIC_IRQ_MIGRATION if SMP 119 select GENERIC_IRQ_PROBE 120 select GENERIC_IRQ_RESERVATION_MODE 121 select GENERIC_IRQ_SHOW 122 select GENERIC_PENDING_IRQ if SMP 123 select GENERIC_SMP_IDLE_THREAD 124 select GENERIC_STRNCPY_FROM_USER 125 select GENERIC_STRNLEN_USER 126 select GENERIC_TIME_VSYSCALL 127 select GENERIC_GETTIMEOFDAY 128 select GUP_GET_PTE_LOW_HIGH if X86_PAE 129 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 130 select HAVE_ACPI_APEI if ACPI 131 select HAVE_ACPI_APEI_NMI if ACPI 132 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 133 select HAVE_ARCH_AUDITSYSCALL 134 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 135 select HAVE_ARCH_JUMP_LABEL 136 select HAVE_ARCH_JUMP_LABEL_RELATIVE 137 select HAVE_ARCH_KASAN if X86_64 138 select HAVE_ARCH_KGDB 139 select HAVE_ARCH_MMAP_RND_BITS if MMU 140 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 141 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 142 select HAVE_ARCH_PREL32_RELOCATIONS 143 select HAVE_ARCH_SECCOMP_FILTER 144 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 145 select HAVE_ARCH_STACKLEAK 146 select HAVE_ARCH_TRACEHOOK 147 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 148 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 149 select HAVE_ARCH_VMAP_STACK if X86_64 150 select HAVE_ARCH_WITHIN_STACK_FRAMES 151 select HAVE_ASM_MODVERSIONS 152 select HAVE_CMPXCHG_DOUBLE 153 select HAVE_CMPXCHG_LOCAL 154 select HAVE_CONTEXT_TRACKING if X86_64 155 select HAVE_COPY_THREAD_TLS 156 select HAVE_C_RECORDMCOUNT 157 select HAVE_DEBUG_KMEMLEAK 158 select HAVE_DMA_CONTIGUOUS 159 select HAVE_DYNAMIC_FTRACE 160 select HAVE_DYNAMIC_FTRACE_WITH_REGS 161 select HAVE_EBPF_JIT 162 select HAVE_EFFICIENT_UNALIGNED_ACCESS 163 select HAVE_EISA 164 select HAVE_EXIT_THREAD 165 select HAVE_FAST_GUP 166 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 167 select HAVE_FTRACE_MCOUNT_RECORD 168 select HAVE_FUNCTION_GRAPH_TRACER 169 select HAVE_FUNCTION_TRACER 170 select HAVE_GCC_PLUGINS 171 select HAVE_HW_BREAKPOINT 172 select HAVE_IDE 173 select HAVE_IOREMAP_PROT 174 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 175 select HAVE_IRQ_TIME_ACCOUNTING 176 select HAVE_KERNEL_BZIP2 177 select HAVE_KERNEL_GZIP 178 select HAVE_KERNEL_LZ4 179 select HAVE_KERNEL_LZMA 180 select HAVE_KERNEL_LZO 181 select HAVE_KERNEL_XZ 182 select HAVE_KPROBES 183 select HAVE_KPROBES_ON_FTRACE 184 select HAVE_FUNCTION_ERROR_INJECTION 185 select HAVE_KRETPROBES 186 select HAVE_KVM 187 select HAVE_LIVEPATCH if X86_64 188 select HAVE_MEMBLOCK_NODE_MAP 189 select HAVE_MIXED_BREAKPOINTS_REGS 190 select HAVE_MOD_ARCH_SPECIFIC 191 select HAVE_MOVE_PMD 192 select HAVE_NMI 193 select HAVE_OPROFILE 194 select HAVE_OPTPROBES 195 select HAVE_PCSPKR_PLATFORM 196 select HAVE_PERF_EVENTS 197 select HAVE_PERF_EVENTS_NMI 198 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 199 select HAVE_PCI 200 select HAVE_PERF_REGS 201 select HAVE_PERF_USER_STACK_DUMP 202 select HAVE_RCU_TABLE_FREE if PARAVIRT 203 select HAVE_REGS_AND_STACK_ACCESS_API 204 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 205 select HAVE_FUNCTION_ARG_ACCESS_API 206 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 207 select HAVE_STACK_VALIDATION if X86_64 208 select HAVE_RSEQ 209 select HAVE_SYSCALL_TRACEPOINTS 210 select HAVE_UNSTABLE_SCHED_CLOCK 211 select HAVE_USER_RETURN_NOTIFIER 212 select HAVE_GENERIC_VDSO 213 select HOTPLUG_SMT if SMP 214 select IRQ_FORCED_THREADING 215 select NEED_SG_DMA_LENGTH 216 select PCI_DOMAINS if PCI 217 select PCI_LOCKLESS_CONFIG if PCI 218 select PERF_EVENTS 219 select RTC_LIB 220 select RTC_MC146818_LIB 221 select SPARSE_IRQ 222 select SRCU 223 select SYSCTL_EXCEPTION_TRACE 224 select THREAD_INFO_IN_TASK 225 select USER_STACKTRACE_SUPPORT 226 select VIRT_TO_BUS 227 select X86_FEATURE_NAMES if PROC_FS 228 select PROC_PID_ARCH_STATUS if PROC_FS 229 select HAVE_ARCH_KCSAN if X86_64 230 231config INSTRUCTION_DECODER 232 def_bool y 233 depends on KPROBES || PERF_EVENTS || UPROBES 234 235config OUTPUT_FORMAT 236 string 237 default "elf32-i386" if X86_32 238 default "elf64-x86-64" if X86_64 239 240config ARCH_DEFCONFIG 241 string 242 default "arch/x86/configs/i386_defconfig" if X86_32 243 default "arch/x86/configs/x86_64_defconfig" if X86_64 244 245config LOCKDEP_SUPPORT 246 def_bool y 247 248config STACKTRACE_SUPPORT 249 def_bool y 250 251config MMU 252 def_bool y 253 254config ARCH_MMAP_RND_BITS_MIN 255 default 28 if 64BIT 256 default 8 257 258config ARCH_MMAP_RND_BITS_MAX 259 default 32 if 64BIT 260 default 16 261 262config ARCH_MMAP_RND_COMPAT_BITS_MIN 263 default 8 264 265config ARCH_MMAP_RND_COMPAT_BITS_MAX 266 default 16 267 268config SBUS 269 bool 270 271config GENERIC_ISA_DMA 272 def_bool y 273 depends on ISA_DMA_API 274 275config GENERIC_BUG 276 def_bool y 277 depends on BUG 278 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 279 280config GENERIC_BUG_RELATIVE_POINTERS 281 bool 282 283config ARCH_MAY_HAVE_PC_FDC 284 def_bool y 285 depends on ISA_DMA_API 286 287config GENERIC_CALIBRATE_DELAY 288 def_bool y 289 290config ARCH_HAS_CPU_RELAX 291 def_bool y 292 293config ARCH_HAS_CACHE_LINE_SIZE 294 def_bool y 295 296config ARCH_HAS_FILTER_PGPROT 297 def_bool y 298 299config HAVE_SETUP_PER_CPU_AREA 300 def_bool y 301 302config NEED_PER_CPU_EMBED_FIRST_CHUNK 303 def_bool y 304 305config NEED_PER_CPU_PAGE_FIRST_CHUNK 306 def_bool y 307 308config ARCH_HIBERNATION_POSSIBLE 309 def_bool y 310 311config ARCH_SUSPEND_POSSIBLE 312 def_bool y 313 314config ARCH_WANT_GENERAL_HUGETLB 315 def_bool y 316 317config ZONE_DMA32 318 def_bool y if X86_64 319 320config AUDIT_ARCH 321 def_bool y if X86_64 322 323config ARCH_SUPPORTS_DEBUG_PAGEALLOC 324 def_bool y 325 326config KASAN_SHADOW_OFFSET 327 hex 328 depends on KASAN 329 default 0xdffffc0000000000 330 331config HAVE_INTEL_TXT 332 def_bool y 333 depends on INTEL_IOMMU && ACPI 334 335config X86_32_SMP 336 def_bool y 337 depends on X86_32 && SMP 338 339config X86_64_SMP 340 def_bool y 341 depends on X86_64 && SMP 342 343config X86_32_LAZY_GS 344 def_bool y 345 depends on X86_32 && !STACKPROTECTOR 346 347config ARCH_SUPPORTS_UPROBES 348 def_bool y 349 350config FIX_EARLYCON_MEM 351 def_bool y 352 353config DYNAMIC_PHYSICAL_MASK 354 bool 355 356config PGTABLE_LEVELS 357 int 358 default 5 if X86_5LEVEL 359 default 4 if X86_64 360 default 3 if X86_PAE 361 default 2 362 363config CC_HAS_SANE_STACKPROTECTOR 364 bool 365 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 366 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 367 help 368 We have to make sure stack protector is unconditionally disabled if 369 the compiler produces broken code. 370 371menu "Processor type and features" 372 373config ZONE_DMA 374 bool "DMA memory allocation support" if EXPERT 375 default y 376 help 377 DMA memory allocation support allows devices with less than 32-bit 378 addressing to allocate within the first 16MB of address space. 379 Disable if no such devices will be used. 380 381 If unsure, say Y. 382 383config SMP 384 bool "Symmetric multi-processing support" 385 ---help--- 386 This enables support for systems with more than one CPU. If you have 387 a system with only one CPU, say N. If you have a system with more 388 than one CPU, say Y. 389 390 If you say N here, the kernel will run on uni- and multiprocessor 391 machines, but will use only one CPU of a multiprocessor machine. If 392 you say Y here, the kernel will run on many, but not all, 393 uniprocessor machines. On a uniprocessor machine, the kernel 394 will run faster if you say N here. 395 396 Note that if you say Y here and choose architecture "586" or 397 "Pentium" under "Processor family", the kernel will not work on 486 398 architectures. Similarly, multiprocessor kernels for the "PPro" 399 architecture may not work on all Pentium based boards. 400 401 People using multiprocessor machines who say Y here should also say 402 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 403 Management" code will be disabled if you say Y here. 404 405 See also <file:Documentation/x86/i386/IO-APIC.rst>, 406 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 407 <http://www.tldp.org/docs.html#howto>. 408 409 If you don't know what to do here, say N. 410 411config X86_FEATURE_NAMES 412 bool "Processor feature human-readable names" if EMBEDDED 413 default y 414 ---help--- 415 This option compiles in a table of x86 feature bits and corresponding 416 names. This is required to support /proc/cpuinfo and a few kernel 417 messages. You can disable this to save space, at the expense of 418 making those few kernel messages show numeric feature bits instead. 419 420 If in doubt, say Y. 421 422config X86_X2APIC 423 bool "Support x2apic" 424 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 425 ---help--- 426 This enables x2apic support on CPUs that have this feature. 427 428 This allows 32-bit apic IDs (so it can support very large systems), 429 and accesses the local apic via MSRs not via mmio. 430 431 If you don't know what to do here, say N. 432 433config X86_MPPARSE 434 bool "Enable MPS table" if ACPI || SFI 435 default y 436 depends on X86_LOCAL_APIC 437 ---help--- 438 For old smp systems that do not have proper acpi support. Newer systems 439 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 440 441config GOLDFISH 442 def_bool y 443 depends on X86_GOLDFISH 444 445config RETPOLINE 446 bool "Avoid speculative indirect branches in kernel" 447 default y 448 select STACK_VALIDATION if HAVE_STACK_VALIDATION 449 help 450 Compile kernel with the retpoline compiler options to guard against 451 kernel-to-user data leaks by avoiding speculative indirect 452 branches. Requires a compiler with -mindirect-branch=thunk-extern 453 support for full protection. The kernel may run slower. 454 455config X86_CPU_RESCTRL 456 bool "x86 CPU resource control support" 457 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 458 select KERNFS 459 help 460 Enable x86 CPU resource control support. 461 462 Provide support for the allocation and monitoring of system resources 463 usage by the CPU. 464 465 Intel calls this Intel Resource Director Technology 466 (Intel(R) RDT). More information about RDT can be found in the 467 Intel x86 Architecture Software Developer Manual. 468 469 AMD calls this AMD Platform Quality of Service (AMD QoS). 470 More information about AMD QoS can be found in the AMD64 Technology 471 Platform Quality of Service Extensions manual. 472 473 Say N if unsure. 474 475if X86_32 476config X86_BIGSMP 477 bool "Support for big SMP systems with more than 8 CPUs" 478 depends on SMP 479 ---help--- 480 This option is needed for the systems that have more than 8 CPUs 481 482config X86_EXTENDED_PLATFORM 483 bool "Support for extended (non-PC) x86 platforms" 484 default y 485 ---help--- 486 If you disable this option then the kernel will only support 487 standard PC platforms. (which covers the vast majority of 488 systems out there.) 489 490 If you enable this option then you'll be able to select support 491 for the following (non-PC) 32 bit x86 platforms: 492 Goldfish (Android emulator) 493 AMD Elan 494 RDC R-321x SoC 495 SGI 320/540 (Visual Workstation) 496 STA2X11-based (e.g. Northville) 497 Moorestown MID devices 498 499 If you have one of these systems, or if you want to build a 500 generic distribution kernel, say Y here - otherwise say N. 501endif 502 503if X86_64 504config X86_EXTENDED_PLATFORM 505 bool "Support for extended (non-PC) x86 platforms" 506 default y 507 ---help--- 508 If you disable this option then the kernel will only support 509 standard PC platforms. (which covers the vast majority of 510 systems out there.) 511 512 If you enable this option then you'll be able to select support 513 for the following (non-PC) 64 bit x86 platforms: 514 Numascale NumaChip 515 ScaleMP vSMP 516 SGI Ultraviolet 517 518 If you have one of these systems, or if you want to build a 519 generic distribution kernel, say Y here - otherwise say N. 520endif 521# This is an alphabetically sorted list of 64 bit extended platforms 522# Please maintain the alphabetic order if and when there are additions 523config X86_NUMACHIP 524 bool "Numascale NumaChip" 525 depends on X86_64 526 depends on X86_EXTENDED_PLATFORM 527 depends on NUMA 528 depends on SMP 529 depends on X86_X2APIC 530 depends on PCI_MMCONFIG 531 ---help--- 532 Adds support for Numascale NumaChip large-SMP systems. Needed to 533 enable more than ~168 cores. 534 If you don't have one of these, you should say N here. 535 536config X86_VSMP 537 bool "ScaleMP vSMP" 538 select HYPERVISOR_GUEST 539 select PARAVIRT 540 depends on X86_64 && PCI 541 depends on X86_EXTENDED_PLATFORM 542 depends on SMP 543 ---help--- 544 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 545 supposed to run on these EM64T-based machines. Only choose this option 546 if you have one of these machines. 547 548config X86_UV 549 bool "SGI Ultraviolet" 550 depends on X86_64 551 depends on X86_EXTENDED_PLATFORM 552 depends on NUMA 553 depends on EFI 554 depends on X86_X2APIC 555 depends on PCI 556 ---help--- 557 This option is needed in order to support SGI Ultraviolet systems. 558 If you don't have one of these, you should say N here. 559 560# Following is an alphabetically sorted list of 32 bit extended platforms 561# Please maintain the alphabetic order if and when there are additions 562 563config X86_GOLDFISH 564 bool "Goldfish (Virtual Platform)" 565 depends on X86_EXTENDED_PLATFORM 566 ---help--- 567 Enable support for the Goldfish virtual platform used primarily 568 for Android development. Unless you are building for the Android 569 Goldfish emulator say N here. 570 571config X86_INTEL_CE 572 bool "CE4100 TV platform" 573 depends on PCI 574 depends on PCI_GODIRECT 575 depends on X86_IO_APIC 576 depends on X86_32 577 depends on X86_EXTENDED_PLATFORM 578 select X86_REBOOTFIXUPS 579 select OF 580 select OF_EARLY_FLATTREE 581 ---help--- 582 Select for the Intel CE media processor (CE4100) SOC. 583 This option compiles in support for the CE4100 SOC for settop 584 boxes and media devices. 585 586config X86_INTEL_MID 587 bool "Intel MID platform support" 588 depends on X86_EXTENDED_PLATFORM 589 depends on X86_PLATFORM_DEVICES 590 depends on PCI 591 depends on X86_64 || (PCI_GOANY && X86_32) 592 depends on X86_IO_APIC 593 select SFI 594 select I2C 595 select DW_APB_TIMER 596 select APB_TIMER 597 select INTEL_SCU_IPC 598 select MFD_INTEL_MSIC 599 ---help--- 600 Select to build a kernel capable of supporting Intel MID (Mobile 601 Internet Device) platform systems which do not have the PCI legacy 602 interfaces. If you are building for a PC class system say N here. 603 604 Intel MID platforms are based on an Intel processor and chipset which 605 consume less power than most of the x86 derivatives. 606 607config X86_INTEL_QUARK 608 bool "Intel Quark platform support" 609 depends on X86_32 610 depends on X86_EXTENDED_PLATFORM 611 depends on X86_PLATFORM_DEVICES 612 depends on X86_TSC 613 depends on PCI 614 depends on PCI_GOANY 615 depends on X86_IO_APIC 616 select IOSF_MBI 617 select INTEL_IMR 618 select COMMON_CLK 619 ---help--- 620 Select to include support for Quark X1000 SoC. 621 Say Y here if you have a Quark based system such as the Arduino 622 compatible Intel Galileo. 623 624config X86_INTEL_LPSS 625 bool "Intel Low Power Subsystem Support" 626 depends on X86 && ACPI && PCI 627 select COMMON_CLK 628 select PINCTRL 629 select IOSF_MBI 630 ---help--- 631 Select to build support for Intel Low Power Subsystem such as 632 found on Intel Lynxpoint PCH. Selecting this option enables 633 things like clock tree (common clock framework) and pincontrol 634 which are needed by the LPSS peripheral drivers. 635 636config X86_AMD_PLATFORM_DEVICE 637 bool "AMD ACPI2Platform devices support" 638 depends on ACPI 639 select COMMON_CLK 640 select PINCTRL 641 ---help--- 642 Select to interpret AMD specific ACPI device to platform device 643 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 644 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 645 implemented under PINCTRL subsystem. 646 647config IOSF_MBI 648 tristate "Intel SoC IOSF Sideband support for SoC platforms" 649 depends on PCI 650 ---help--- 651 This option enables sideband register access support for Intel SoC 652 platforms. On these platforms the IOSF sideband is used in lieu of 653 MSR's for some register accesses, mostly but not limited to thermal 654 and power. Drivers may query the availability of this device to 655 determine if they need the sideband in order to work on these 656 platforms. The sideband is available on the following SoC products. 657 This list is not meant to be exclusive. 658 - BayTrail 659 - Braswell 660 - Quark 661 662 You should say Y if you are running a kernel on one of these SoC's. 663 664config IOSF_MBI_DEBUG 665 bool "Enable IOSF sideband access through debugfs" 666 depends on IOSF_MBI && DEBUG_FS 667 ---help--- 668 Select this option to expose the IOSF sideband access registers (MCR, 669 MDR, MCRX) through debugfs to write and read register information from 670 different units on the SoC. This is most useful for obtaining device 671 state information for debug and analysis. As this is a general access 672 mechanism, users of this option would have specific knowledge of the 673 device they want to access. 674 675 If you don't require the option or are in doubt, say N. 676 677config X86_RDC321X 678 bool "RDC R-321x SoC" 679 depends on X86_32 680 depends on X86_EXTENDED_PLATFORM 681 select M486 682 select X86_REBOOTFIXUPS 683 ---help--- 684 This option is needed for RDC R-321x system-on-chip, also known 685 as R-8610-(G). 686 If you don't have one of these chips, you should say N here. 687 688config X86_32_NON_STANDARD 689 bool "Support non-standard 32-bit SMP architectures" 690 depends on X86_32 && SMP 691 depends on X86_EXTENDED_PLATFORM 692 ---help--- 693 This option compiles in the bigsmp and STA2X11 default 694 subarchitectures. It is intended for a generic binary 695 kernel. If you select them all, kernel will probe it one by 696 one and will fallback to default. 697 698# Alphabetically sorted list of Non standard 32 bit platforms 699 700config X86_SUPPORTS_MEMORY_FAILURE 701 def_bool y 702 # MCE code calls memory_failure(): 703 depends on X86_MCE 704 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 705 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 706 depends on X86_64 || !SPARSEMEM 707 select ARCH_SUPPORTS_MEMORY_FAILURE 708 709config STA2X11 710 bool "STA2X11 Companion Chip Support" 711 depends on X86_32_NON_STANDARD && PCI 712 select ARCH_HAS_PHYS_TO_DMA 713 select SWIOTLB 714 select MFD_STA2X11 715 select GPIOLIB 716 ---help--- 717 This adds support for boards based on the STA2X11 IO-Hub, 718 a.k.a. "ConneXt". The chip is used in place of the standard 719 PC chipset, so all "standard" peripherals are missing. If this 720 option is selected the kernel will still be able to boot on 721 standard PC machines. 722 723config X86_32_IRIS 724 tristate "Eurobraille/Iris poweroff module" 725 depends on X86_32 726 ---help--- 727 The Iris machines from EuroBraille do not have APM or ACPI support 728 to shut themselves down properly. A special I/O sequence is 729 needed to do so, which is what this module does at 730 kernel shutdown. 731 732 This is only for Iris machines from EuroBraille. 733 734 If unused, say N. 735 736config SCHED_OMIT_FRAME_POINTER 737 def_bool y 738 prompt "Single-depth WCHAN output" 739 depends on X86 740 ---help--- 741 Calculate simpler /proc/<PID>/wchan values. If this option 742 is disabled then wchan values will recurse back to the 743 caller function. This provides more accurate wchan values, 744 at the expense of slightly more scheduling overhead. 745 746 If in doubt, say "Y". 747 748menuconfig HYPERVISOR_GUEST 749 bool "Linux guest support" 750 ---help--- 751 Say Y here to enable options for running Linux under various hyper- 752 visors. This option enables basic hypervisor detection and platform 753 setup. 754 755 If you say N, all options in this submenu will be skipped and 756 disabled, and Linux guest support won't be built in. 757 758if HYPERVISOR_GUEST 759 760config PARAVIRT 761 bool "Enable paravirtualization code" 762 ---help--- 763 This changes the kernel so it can modify itself when it is run 764 under a hypervisor, potentially improving performance significantly 765 over full virtualization. However, when run without a hypervisor 766 the kernel is theoretically slower and slightly larger. 767 768config PARAVIRT_XXL 769 bool 770 771config PARAVIRT_DEBUG 772 bool "paravirt-ops debugging" 773 depends on PARAVIRT && DEBUG_KERNEL 774 ---help--- 775 Enable to debug paravirt_ops internals. Specifically, BUG if 776 a paravirt_op is missing when it is called. 777 778config PARAVIRT_SPINLOCKS 779 bool "Paravirtualization layer for spinlocks" 780 depends on PARAVIRT && SMP 781 ---help--- 782 Paravirtualized spinlocks allow a pvops backend to replace the 783 spinlock implementation with something virtualization-friendly 784 (for example, block the virtual CPU rather than spinning). 785 786 It has a minimal impact on native kernels and gives a nice performance 787 benefit on paravirtualized KVM / Xen kernels. 788 789 If you are unsure how to answer this question, answer Y. 790 791config X86_HV_CALLBACK_VECTOR 792 def_bool n 793 794source "arch/x86/xen/Kconfig" 795 796config KVM_GUEST 797 bool "KVM Guest support (including kvmclock)" 798 depends on PARAVIRT 799 select PARAVIRT_CLOCK 800 select ARCH_CPUIDLE_HALTPOLL 801 default y 802 ---help--- 803 This option enables various optimizations for running under the KVM 804 hypervisor. It includes a paravirtualized clock, so that instead 805 of relying on a PIT (or probably other) emulation by the 806 underlying device model, the host provides the guest with 807 timing infrastructure such as time of day, and system time 808 809config ARCH_CPUIDLE_HALTPOLL 810 def_bool n 811 prompt "Disable host haltpoll when loading haltpoll driver" 812 help 813 If virtualized under KVM, disable host haltpoll. 814 815config PVH 816 bool "Support for running PVH guests" 817 ---help--- 818 This option enables the PVH entry point for guest virtual machines 819 as specified in the x86/HVM direct boot ABI. 820 821config KVM_DEBUG_FS 822 bool "Enable debug information for KVM Guests in debugfs" 823 depends on KVM_GUEST && DEBUG_FS 824 ---help--- 825 This option enables collection of various statistics for KVM guest. 826 Statistics are displayed in debugfs filesystem. Enabling this option 827 may incur significant overhead. 828 829config PARAVIRT_TIME_ACCOUNTING 830 bool "Paravirtual steal time accounting" 831 depends on PARAVIRT 832 ---help--- 833 Select this option to enable fine granularity task steal time 834 accounting. Time spent executing other tasks in parallel with 835 the current vCPU is discounted from the vCPU power. To account for 836 that, there can be a small performance impact. 837 838 If in doubt, say N here. 839 840config PARAVIRT_CLOCK 841 bool 842 843config JAILHOUSE_GUEST 844 bool "Jailhouse non-root cell support" 845 depends on X86_64 && PCI 846 select X86_PM_TIMER 847 ---help--- 848 This option allows to run Linux as guest in a Jailhouse non-root 849 cell. You can leave this option disabled if you only want to start 850 Jailhouse and run Linux afterwards in the root cell. 851 852config ACRN_GUEST 853 bool "ACRN Guest support" 854 depends on X86_64 855 select X86_HV_CALLBACK_VECTOR 856 help 857 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 858 a flexible, lightweight reference open-source hypervisor, built with 859 real-time and safety-criticality in mind. It is built for embedded 860 IOT with small footprint and real-time features. More details can be 861 found in https://projectacrn.org/. 862 863endif #HYPERVISOR_GUEST 864 865source "arch/x86/Kconfig.cpu" 866 867config HPET_TIMER 868 def_bool X86_64 869 prompt "HPET Timer Support" if X86_32 870 ---help--- 871 Use the IA-PC HPET (High Precision Event Timer) to manage 872 time in preference to the PIT and RTC, if a HPET is 873 present. 874 HPET is the next generation timer replacing legacy 8254s. 875 The HPET provides a stable time base on SMP 876 systems, unlike the TSC, but it is more expensive to access, 877 as it is off-chip. The interface used is documented 878 in the HPET spec, revision 1. 879 880 You can safely choose Y here. However, HPET will only be 881 activated if the platform and the BIOS support this feature. 882 Otherwise the 8254 will be used for timing services. 883 884 Choose N to continue using the legacy 8254 timer. 885 886config HPET_EMULATE_RTC 887 def_bool y 888 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 889 890config APB_TIMER 891 def_bool y if X86_INTEL_MID 892 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 893 select DW_APB_TIMER 894 depends on X86_INTEL_MID && SFI 895 help 896 APB timer is the replacement for 8254, HPET on X86 MID platforms. 897 The APBT provides a stable time base on SMP 898 systems, unlike the TSC, but it is more expensive to access, 899 as it is off-chip. APB timers are always running regardless of CPU 900 C states, they are used as per CPU clockevent device when possible. 901 902# Mark as expert because too many people got it wrong. 903# The code disables itself when not needed. 904config DMI 905 default y 906 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 907 bool "Enable DMI scanning" if EXPERT 908 ---help--- 909 Enabled scanning of DMI to identify machine quirks. Say Y 910 here unless you have verified that your setup is not 911 affected by entries in the DMI blacklist. Required by PNP 912 BIOS code. 913 914config GART_IOMMU 915 bool "Old AMD GART IOMMU support" 916 select IOMMU_HELPER 917 select SWIOTLB 918 depends on X86_64 && PCI && AMD_NB 919 ---help--- 920 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 921 GART based hardware IOMMUs. 922 923 The GART supports full DMA access for devices with 32-bit access 924 limitations, on systems with more than 3 GB. This is usually needed 925 for USB, sound, many IDE/SATA chipsets and some other devices. 926 927 Newer systems typically have a modern AMD IOMMU, supported via 928 the CONFIG_AMD_IOMMU=y config option. 929 930 In normal configurations this driver is only active when needed: 931 there's more than 3 GB of memory and the system contains a 932 32-bit limited device. 933 934 If unsure, say Y. 935 936config CALGARY_IOMMU 937 bool "IBM Calgary IOMMU support" 938 select IOMMU_HELPER 939 select SWIOTLB 940 depends on X86_64 && PCI 941 ---help--- 942 Support for hardware IOMMUs in IBM's xSeries x366 and x460 943 systems. Needed to run systems with more than 3GB of memory 944 properly with 32-bit PCI devices that do not support DAC 945 (Double Address Cycle). Calgary also supports bus level 946 isolation, where all DMAs pass through the IOMMU. This 947 prevents them from going anywhere except their intended 948 destination. This catches hard-to-find kernel bugs and 949 mis-behaving drivers and devices that do not use the DMA-API 950 properly to set up their DMA buffers. The IOMMU can be 951 turned off at boot time with the iommu=off parameter. 952 Normally the kernel will make the right choice by itself. 953 If unsure, say Y. 954 955config CALGARY_IOMMU_ENABLED_BY_DEFAULT 956 def_bool y 957 prompt "Should Calgary be enabled by default?" 958 depends on CALGARY_IOMMU 959 ---help--- 960 Should Calgary be enabled by default? if you choose 'y', Calgary 961 will be used (if it exists). If you choose 'n', Calgary will not be 962 used even if it exists. If you choose 'n' and would like to use 963 Calgary anyway, pass 'iommu=calgary' on the kernel command line. 964 If unsure, say Y. 965 966config MAXSMP 967 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 968 depends on X86_64 && SMP && DEBUG_KERNEL 969 select CPUMASK_OFFSTACK 970 ---help--- 971 Enable maximum number of CPUS and NUMA Nodes for this architecture. 972 If unsure, say N. 973 974# 975# The maximum number of CPUs supported: 976# 977# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 978# and which can be configured interactively in the 979# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 980# 981# The ranges are different on 32-bit and 64-bit kernels, depending on 982# hardware capabilities and scalability features of the kernel. 983# 984# ( If MAXSMP is enabled we just use the highest possible value and disable 985# interactive configuration. ) 986# 987 988config NR_CPUS_RANGE_BEGIN 989 int 990 default NR_CPUS_RANGE_END if MAXSMP 991 default 1 if !SMP 992 default 2 993 994config NR_CPUS_RANGE_END 995 int 996 depends on X86_32 997 default 64 if SMP && X86_BIGSMP 998 default 8 if SMP && !X86_BIGSMP 999 default 1 if !SMP 1000 1001config NR_CPUS_RANGE_END 1002 int 1003 depends on X86_64 1004 default 8192 if SMP && ( MAXSMP || CPUMASK_OFFSTACK) 1005 default 512 if SMP && (!MAXSMP && !CPUMASK_OFFSTACK) 1006 default 1 if !SMP 1007 1008config NR_CPUS_DEFAULT 1009 int 1010 depends on X86_32 1011 default 32 if X86_BIGSMP 1012 default 8 if SMP 1013 default 1 if !SMP 1014 1015config NR_CPUS_DEFAULT 1016 int 1017 depends on X86_64 1018 default 8192 if MAXSMP 1019 default 64 if SMP 1020 default 1 if !SMP 1021 1022config NR_CPUS 1023 int "Maximum number of CPUs" if SMP && !MAXSMP 1024 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1025 default NR_CPUS_DEFAULT 1026 ---help--- 1027 This allows you to specify the maximum number of CPUs which this 1028 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1029 supported value is 8192, otherwise the maximum value is 512. The 1030 minimum value which makes sense is 2. 1031 1032 This is purely to save memory: each supported CPU adds about 8KB 1033 to the kernel image. 1034 1035config SCHED_SMT 1036 def_bool y if SMP 1037 1038config SCHED_MC 1039 def_bool y 1040 prompt "Multi-core scheduler support" 1041 depends on SMP 1042 ---help--- 1043 Multi-core scheduler support improves the CPU scheduler's decision 1044 making when dealing with multi-core CPU chips at a cost of slightly 1045 increased overhead in some places. If unsure say N here. 1046 1047config SCHED_MC_PRIO 1048 bool "CPU core priorities scheduler support" 1049 depends on SCHED_MC && CPU_SUP_INTEL 1050 select X86_INTEL_PSTATE 1051 select CPU_FREQ 1052 default y 1053 ---help--- 1054 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1055 core ordering determined at manufacturing time, which allows 1056 certain cores to reach higher turbo frequencies (when running 1057 single threaded workloads) than others. 1058 1059 Enabling this kernel feature teaches the scheduler about 1060 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1061 scheduler's CPU selection logic accordingly, so that higher 1062 overall system performance can be achieved. 1063 1064 This feature will have no effect on CPUs without this feature. 1065 1066 If unsure say Y here. 1067 1068config UP_LATE_INIT 1069 def_bool y 1070 depends on !SMP && X86_LOCAL_APIC 1071 1072config X86_UP_APIC 1073 bool "Local APIC support on uniprocessors" if !PCI_MSI 1074 default PCI_MSI 1075 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1076 ---help--- 1077 A local APIC (Advanced Programmable Interrupt Controller) is an 1078 integrated interrupt controller in the CPU. If you have a single-CPU 1079 system which has a processor with a local APIC, you can say Y here to 1080 enable and use it. If you say Y here even though your machine doesn't 1081 have a local APIC, then the kernel will still run with no slowdown at 1082 all. The local APIC supports CPU-generated self-interrupts (timer, 1083 performance counters), and the NMI watchdog which detects hard 1084 lockups. 1085 1086config X86_UP_IOAPIC 1087 bool "IO-APIC support on uniprocessors" 1088 depends on X86_UP_APIC 1089 ---help--- 1090 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1091 SMP-capable replacement for PC-style interrupt controllers. Most 1092 SMP systems and many recent uniprocessor systems have one. 1093 1094 If you have a single-CPU system with an IO-APIC, you can say Y here 1095 to use it. If you say Y here even though your machine doesn't have 1096 an IO-APIC, then the kernel will still run with no slowdown at all. 1097 1098config X86_LOCAL_APIC 1099 def_bool y 1100 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1101 select IRQ_DOMAIN_HIERARCHY 1102 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1103 1104config X86_IO_APIC 1105 def_bool y 1106 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1107 1108config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1109 bool "Reroute for broken boot IRQs" 1110 depends on X86_IO_APIC 1111 ---help--- 1112 This option enables a workaround that fixes a source of 1113 spurious interrupts. This is recommended when threaded 1114 interrupt handling is used on systems where the generation of 1115 superfluous "boot interrupts" cannot be disabled. 1116 1117 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1118 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1119 kernel does during interrupt handling). On chipsets where this 1120 boot IRQ generation cannot be disabled, this workaround keeps 1121 the original IRQ line masked so that only the equivalent "boot 1122 IRQ" is delivered to the CPUs. The workaround also tells the 1123 kernel to set up the IRQ handler on the boot IRQ line. In this 1124 way only one interrupt is delivered to the kernel. Otherwise 1125 the spurious second interrupt may cause the kernel to bring 1126 down (vital) interrupt lines. 1127 1128 Only affects "broken" chipsets. Interrupt sharing may be 1129 increased on these systems. 1130 1131config X86_MCE 1132 bool "Machine Check / overheating reporting" 1133 select GENERIC_ALLOCATOR 1134 default y 1135 ---help--- 1136 Machine Check support allows the processor to notify the 1137 kernel if it detects a problem (e.g. overheating, data corruption). 1138 The action the kernel takes depends on the severity of the problem, 1139 ranging from warning messages to halting the machine. 1140 1141config X86_MCELOG_LEGACY 1142 bool "Support for deprecated /dev/mcelog character device" 1143 depends on X86_MCE 1144 ---help--- 1145 Enable support for /dev/mcelog which is needed by the old mcelog 1146 userspace logging daemon. Consider switching to the new generation 1147 rasdaemon solution. 1148 1149config X86_MCE_INTEL 1150 def_bool y 1151 prompt "Intel MCE features" 1152 depends on X86_MCE && X86_LOCAL_APIC 1153 ---help--- 1154 Additional support for intel specific MCE features such as 1155 the thermal monitor. 1156 1157config X86_MCE_AMD 1158 def_bool y 1159 prompt "AMD MCE features" 1160 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1161 ---help--- 1162 Additional support for AMD specific MCE features such as 1163 the DRAM Error Threshold. 1164 1165config X86_ANCIENT_MCE 1166 bool "Support for old Pentium 5 / WinChip machine checks" 1167 depends on X86_32 && X86_MCE 1168 ---help--- 1169 Include support for machine check handling on old Pentium 5 or WinChip 1170 systems. These typically need to be enabled explicitly on the command 1171 line. 1172 1173config X86_MCE_THRESHOLD 1174 depends on X86_MCE_AMD || X86_MCE_INTEL 1175 def_bool y 1176 1177config X86_MCE_INJECT 1178 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1179 tristate "Machine check injector support" 1180 ---help--- 1181 Provide support for injecting machine checks for testing purposes. 1182 If you don't know what a machine check is and you don't do kernel 1183 QA it is safe to say n. 1184 1185config X86_THERMAL_VECTOR 1186 def_bool y 1187 depends on X86_MCE_INTEL 1188 1189source "arch/x86/events/Kconfig" 1190 1191config X86_LEGACY_VM86 1192 bool "Legacy VM86 support" 1193 depends on X86_32 1194 ---help--- 1195 This option allows user programs to put the CPU into V8086 1196 mode, which is an 80286-era approximation of 16-bit real mode. 1197 1198 Some very old versions of X and/or vbetool require this option 1199 for user mode setting. Similarly, DOSEMU will use it if 1200 available to accelerate real mode DOS programs. However, any 1201 recent version of DOSEMU, X, or vbetool should be fully 1202 functional even without kernel VM86 support, as they will all 1203 fall back to software emulation. Nevertheless, if you are using 1204 a 16-bit DOS program where 16-bit performance matters, vm86 1205 mode might be faster than emulation and you might want to 1206 enable this option. 1207 1208 Note that any app that works on a 64-bit kernel is unlikely to 1209 need this option, as 64-bit kernels don't, and can't, support 1210 V8086 mode. This option is also unrelated to 16-bit protected 1211 mode and is not needed to run most 16-bit programs under Wine. 1212 1213 Enabling this option increases the complexity of the kernel 1214 and slows down exception handling a tiny bit. 1215 1216 If unsure, say N here. 1217 1218config VM86 1219 bool 1220 default X86_LEGACY_VM86 1221 1222config X86_16BIT 1223 bool "Enable support for 16-bit segments" if EXPERT 1224 default y 1225 depends on MODIFY_LDT_SYSCALL 1226 ---help--- 1227 This option is required by programs like Wine to run 16-bit 1228 protected mode legacy code on x86 processors. Disabling 1229 this option saves about 300 bytes on i386, or around 6K text 1230 plus 16K runtime memory on x86-64, 1231 1232config X86_ESPFIX32 1233 def_bool y 1234 depends on X86_16BIT && X86_32 1235 1236config X86_ESPFIX64 1237 def_bool y 1238 depends on X86_16BIT && X86_64 1239 1240config X86_VSYSCALL_EMULATION 1241 bool "Enable vsyscall emulation" if EXPERT 1242 default y 1243 depends on X86_64 1244 ---help--- 1245 This enables emulation of the legacy vsyscall page. Disabling 1246 it is roughly equivalent to booting with vsyscall=none, except 1247 that it will also disable the helpful warning if a program 1248 tries to use a vsyscall. With this option set to N, offending 1249 programs will just segfault, citing addresses of the form 1250 0xffffffffff600?00. 1251 1252 This option is required by many programs built before 2013, and 1253 care should be used even with newer programs if set to N. 1254 1255 Disabling this option saves about 7K of kernel size and 1256 possibly 4K of additional runtime pagetable memory. 1257 1258config TOSHIBA 1259 tristate "Toshiba Laptop support" 1260 depends on X86_32 1261 ---help--- 1262 This adds a driver to safely access the System Management Mode of 1263 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1264 not work on models with a Phoenix BIOS. The System Management Mode 1265 is used to set the BIOS and power saving options on Toshiba portables. 1266 1267 For information on utilities to make use of this driver see the 1268 Toshiba Linux utilities web site at: 1269 <http://www.buzzard.org.uk/toshiba/>. 1270 1271 Say Y if you intend to run this kernel on a Toshiba portable. 1272 Say N otherwise. 1273 1274config I8K 1275 tristate "Dell i8k legacy laptop support" 1276 select HWMON 1277 select SENSORS_DELL_SMM 1278 ---help--- 1279 This option enables legacy /proc/i8k userspace interface in hwmon 1280 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1281 temperature and allows controlling fan speeds of Dell laptops via 1282 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1283 it reports also power and hotkey status. For fan speed control is 1284 needed userspace package i8kutils. 1285 1286 Say Y if you intend to run this kernel on old Dell laptops or want to 1287 use userspace package i8kutils. 1288 Say N otherwise. 1289 1290config X86_REBOOTFIXUPS 1291 bool "Enable X86 board specific fixups for reboot" 1292 depends on X86_32 1293 ---help--- 1294 This enables chipset and/or board specific fixups to be done 1295 in order to get reboot to work correctly. This is only needed on 1296 some combinations of hardware and BIOS. The symptom, for which 1297 this config is intended, is when reboot ends with a stalled/hung 1298 system. 1299 1300 Currently, the only fixup is for the Geode machines using 1301 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1302 1303 Say Y if you want to enable the fixup. Currently, it's safe to 1304 enable this option even if you don't need it. 1305 Say N otherwise. 1306 1307config MICROCODE 1308 bool "CPU microcode loading support" 1309 default y 1310 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1311 select FW_LOADER 1312 ---help--- 1313 If you say Y here, you will be able to update the microcode on 1314 Intel and AMD processors. The Intel support is for the IA32 family, 1315 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1316 AMD support is for families 0x10 and later. You will obviously need 1317 the actual microcode binary data itself which is not shipped with 1318 the Linux kernel. 1319 1320 The preferred method to load microcode from a detached initrd is described 1321 in Documentation/x86/microcode.rst. For that you need to enable 1322 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1323 initrd for microcode blobs. 1324 1325 In addition, you can build the microcode into the kernel. For that you 1326 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1327 config option. 1328 1329config MICROCODE_INTEL 1330 bool "Intel microcode loading support" 1331 depends on MICROCODE 1332 default MICROCODE 1333 select FW_LOADER 1334 ---help--- 1335 This options enables microcode patch loading support for Intel 1336 processors. 1337 1338 For the current Intel microcode data package go to 1339 <https://downloadcenter.intel.com> and search for 1340 'Linux Processor Microcode Data File'. 1341 1342config MICROCODE_AMD 1343 bool "AMD microcode loading support" 1344 depends on MICROCODE 1345 select FW_LOADER 1346 ---help--- 1347 If you select this option, microcode patch loading support for AMD 1348 processors will be enabled. 1349 1350config MICROCODE_OLD_INTERFACE 1351 bool "Ancient loading interface (DEPRECATED)" 1352 default n 1353 depends on MICROCODE 1354 ---help--- 1355 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1356 which was used by userspace tools like iucode_tool and microcode.ctl. 1357 It is inadequate because it runs too late to be able to properly 1358 load microcode on a machine and it needs special tools. Instead, you 1359 should've switched to the early loading method with the initrd or 1360 builtin microcode by now: Documentation/x86/microcode.rst 1361 1362config X86_MSR 1363 tristate "/dev/cpu/*/msr - Model-specific register support" 1364 ---help--- 1365 This device gives privileged processes access to the x86 1366 Model-Specific Registers (MSRs). It is a character device with 1367 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1368 MSR accesses are directed to a specific CPU on multi-processor 1369 systems. 1370 1371config X86_CPUID 1372 tristate "/dev/cpu/*/cpuid - CPU information support" 1373 ---help--- 1374 This device gives processes access to the x86 CPUID instruction to 1375 be executed on a specific processor. It is a character device 1376 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1377 /dev/cpu/31/cpuid. 1378 1379choice 1380 prompt "High Memory Support" 1381 default HIGHMEM4G 1382 depends on X86_32 1383 1384config NOHIGHMEM 1385 bool "off" 1386 ---help--- 1387 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1388 However, the address space of 32-bit x86 processors is only 4 1389 Gigabytes large. That means that, if you have a large amount of 1390 physical memory, not all of it can be "permanently mapped" by the 1391 kernel. The physical memory that's not permanently mapped is called 1392 "high memory". 1393 1394 If you are compiling a kernel which will never run on a machine with 1395 more than 1 Gigabyte total physical RAM, answer "off" here (default 1396 choice and suitable for most users). This will result in a "3GB/1GB" 1397 split: 3GB are mapped so that each process sees a 3GB virtual memory 1398 space and the remaining part of the 4GB virtual memory space is used 1399 by the kernel to permanently map as much physical memory as 1400 possible. 1401 1402 If the machine has between 1 and 4 Gigabytes physical RAM, then 1403 answer "4GB" here. 1404 1405 If more than 4 Gigabytes is used then answer "64GB" here. This 1406 selection turns Intel PAE (Physical Address Extension) mode on. 1407 PAE implements 3-level paging on IA32 processors. PAE is fully 1408 supported by Linux, PAE mode is implemented on all recent Intel 1409 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1410 then the kernel will not boot on CPUs that don't support PAE! 1411 1412 The actual amount of total physical memory will either be 1413 auto detected or can be forced by using a kernel command line option 1414 such as "mem=256M". (Try "man bootparam" or see the documentation of 1415 your boot loader (lilo or loadlin) about how to pass options to the 1416 kernel at boot time.) 1417 1418 If unsure, say "off". 1419 1420config HIGHMEM4G 1421 bool "4GB" 1422 ---help--- 1423 Select this if you have a 32-bit processor and between 1 and 4 1424 gigabytes of physical RAM. 1425 1426config HIGHMEM64G 1427 bool "64GB" 1428 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1429 select X86_PAE 1430 ---help--- 1431 Select this if you have a 32-bit processor and more than 4 1432 gigabytes of physical RAM. 1433 1434endchoice 1435 1436choice 1437 prompt "Memory split" if EXPERT 1438 default VMSPLIT_3G 1439 depends on X86_32 1440 ---help--- 1441 Select the desired split between kernel and user memory. 1442 1443 If the address range available to the kernel is less than the 1444 physical memory installed, the remaining memory will be available 1445 as "high memory". Accessing high memory is a little more costly 1446 than low memory, as it needs to be mapped into the kernel first. 1447 Note that increasing the kernel address space limits the range 1448 available to user programs, making the address space there 1449 tighter. Selecting anything other than the default 3G/1G split 1450 will also likely make your kernel incompatible with binary-only 1451 kernel modules. 1452 1453 If you are not absolutely sure what you are doing, leave this 1454 option alone! 1455 1456 config VMSPLIT_3G 1457 bool "3G/1G user/kernel split" 1458 config VMSPLIT_3G_OPT 1459 depends on !X86_PAE 1460 bool "3G/1G user/kernel split (for full 1G low memory)" 1461 config VMSPLIT_2G 1462 bool "2G/2G user/kernel split" 1463 config VMSPLIT_2G_OPT 1464 depends on !X86_PAE 1465 bool "2G/2G user/kernel split (for full 2G low memory)" 1466 config VMSPLIT_1G 1467 bool "1G/3G user/kernel split" 1468endchoice 1469 1470config PAGE_OFFSET 1471 hex 1472 default 0xB0000000 if VMSPLIT_3G_OPT 1473 default 0x80000000 if VMSPLIT_2G 1474 default 0x78000000 if VMSPLIT_2G_OPT 1475 default 0x40000000 if VMSPLIT_1G 1476 default 0xC0000000 1477 depends on X86_32 1478 1479config HIGHMEM 1480 def_bool y 1481 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1482 1483config X86_PAE 1484 bool "PAE (Physical Address Extension) Support" 1485 depends on X86_32 && !HIGHMEM4G 1486 select PHYS_ADDR_T_64BIT 1487 select SWIOTLB 1488 ---help--- 1489 PAE is required for NX support, and furthermore enables 1490 larger swapspace support for non-overcommit purposes. It 1491 has the cost of more pagetable lookup overhead, and also 1492 consumes more pagetable space per process. 1493 1494config X86_5LEVEL 1495 bool "Enable 5-level page tables support" 1496 select DYNAMIC_MEMORY_LAYOUT 1497 select SPARSEMEM_VMEMMAP 1498 depends on X86_64 1499 ---help--- 1500 5-level paging enables access to larger address space: 1501 upto 128 PiB of virtual address space and 4 PiB of 1502 physical address space. 1503 1504 It will be supported by future Intel CPUs. 1505 1506 A kernel with the option enabled can be booted on machines that 1507 support 4- or 5-level paging. 1508 1509 See Documentation/x86/x86_64/5level-paging.rst for more 1510 information. 1511 1512 Say N if unsure. 1513 1514config X86_DIRECT_GBPAGES 1515 def_bool y 1516 depends on X86_64 1517 ---help--- 1518 Certain kernel features effectively disable kernel 1519 linear 1 GB mappings (even if the CPU otherwise 1520 supports them), so don't confuse the user by printing 1521 that we have them enabled. 1522 1523config X86_CPA_STATISTICS 1524 bool "Enable statistic for Change Page Attribute" 1525 depends on DEBUG_FS 1526 ---help--- 1527 Expose statistics about the Change Page Attribute mechanims, which 1528 helps to determine the effectiveness of preserving large and huge 1529 page mappings when mapping protections are changed. 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_SIG 2036 bool "Verify kernel signature during kexec_file_load() syscall" 2037 depends on KEXEC_FILE 2038 ---help--- 2039 2040 This option makes the kexec_file_load() syscall check for a valid 2041 signature of the kernel image. The image can still be loaded without 2042 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2043 there's a signature that we can check, then it must be valid. 2044 2045 In addition to this option, you need to enable signature 2046 verification for the corresponding kernel image type being 2047 loaded in order for this to work. 2048 2049config KEXEC_SIG_FORCE 2050 bool "Require a valid signature in kexec_file_load() syscall" 2051 depends on KEXEC_SIG 2052 ---help--- 2053 This option makes kernel signature verification mandatory for 2054 the kexec_file_load() syscall. 2055 2056config KEXEC_BZIMAGE_VERIFY_SIG 2057 bool "Enable bzImage signature verification support" 2058 depends on KEXEC_SIG 2059 depends on SIGNED_PE_FILE_VERIFICATION 2060 select SYSTEM_TRUSTED_KEYRING 2061 ---help--- 2062 Enable bzImage signature verification support. 2063 2064config CRASH_DUMP 2065 bool "kernel crash dumps" 2066 depends on X86_64 || (X86_32 && HIGHMEM) 2067 ---help--- 2068 Generate crash dump after being started by kexec. 2069 This should be normally only set in special crash dump kernels 2070 which are loaded in the main kernel with kexec-tools into 2071 a specially reserved region and then later executed after 2072 a crash by kdump/kexec. The crash dump kernel must be compiled 2073 to a memory address not used by the main kernel or BIOS using 2074 PHYSICAL_START, or it must be built as a relocatable image 2075 (CONFIG_RELOCATABLE=y). 2076 For more details see Documentation/admin-guide/kdump/kdump.rst 2077 2078config KEXEC_JUMP 2079 bool "kexec jump" 2080 depends on KEXEC && HIBERNATION 2081 ---help--- 2082 Jump between original kernel and kexeced kernel and invoke 2083 code in physical address mode via KEXEC 2084 2085config PHYSICAL_START 2086 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2087 default "0x1000000" 2088 ---help--- 2089 This gives the physical address where the kernel is loaded. 2090 2091 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2092 bzImage will decompress itself to above physical address and 2093 run from there. Otherwise, bzImage will run from the address where 2094 it has been loaded by the boot loader and will ignore above physical 2095 address. 2096 2097 In normal kdump cases one does not have to set/change this option 2098 as now bzImage can be compiled as a completely relocatable image 2099 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2100 address. This option is mainly useful for the folks who don't want 2101 to use a bzImage for capturing the crash dump and want to use a 2102 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2103 to be specifically compiled to run from a specific memory area 2104 (normally a reserved region) and this option comes handy. 2105 2106 So if you are using bzImage for capturing the crash dump, 2107 leave the value here unchanged to 0x1000000 and set 2108 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2109 for capturing the crash dump change this value to start of 2110 the reserved region. In other words, it can be set based on 2111 the "X" value as specified in the "crashkernel=YM@XM" 2112 command line boot parameter passed to the panic-ed 2113 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2114 for more details about crash dumps. 2115 2116 Usage of bzImage for capturing the crash dump is recommended as 2117 one does not have to build two kernels. Same kernel can be used 2118 as production kernel and capture kernel. Above option should have 2119 gone away after relocatable bzImage support is introduced. But it 2120 is present because there are users out there who continue to use 2121 vmlinux for dump capture. This option should go away down the 2122 line. 2123 2124 Don't change this unless you know what you are doing. 2125 2126config RELOCATABLE 2127 bool "Build a relocatable kernel" 2128 default y 2129 ---help--- 2130 This builds a kernel image that retains relocation information 2131 so it can be loaded someplace besides the default 1MB. 2132 The relocations tend to make the kernel binary about 10% larger, 2133 but are discarded at runtime. 2134 2135 One use is for the kexec on panic case where the recovery kernel 2136 must live at a different physical address than the primary 2137 kernel. 2138 2139 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2140 it has been loaded at and the compile time physical address 2141 (CONFIG_PHYSICAL_START) is used as the minimum location. 2142 2143config RANDOMIZE_BASE 2144 bool "Randomize the address of the kernel image (KASLR)" 2145 depends on RELOCATABLE 2146 default y 2147 ---help--- 2148 In support of Kernel Address Space Layout Randomization (KASLR), 2149 this randomizes the physical address at which the kernel image 2150 is decompressed and the virtual address where the kernel 2151 image is mapped, as a security feature that deters exploit 2152 attempts relying on knowledge of the location of kernel 2153 code internals. 2154 2155 On 64-bit, the kernel physical and virtual addresses are 2156 randomized separately. The physical address will be anywhere 2157 between 16MB and the top of physical memory (up to 64TB). The 2158 virtual address will be randomized from 16MB up to 1GB (9 bits 2159 of entropy). Note that this also reduces the memory space 2160 available to kernel modules from 1.5GB to 1GB. 2161 2162 On 32-bit, the kernel physical and virtual addresses are 2163 randomized together. They will be randomized from 16MB up to 2164 512MB (8 bits of entropy). 2165 2166 Entropy is generated using the RDRAND instruction if it is 2167 supported. If RDTSC is supported, its value is mixed into 2168 the entropy pool as well. If neither RDRAND nor RDTSC are 2169 supported, then entropy is read from the i8254 timer. The 2170 usable entropy is limited by the kernel being built using 2171 2GB addressing, and that PHYSICAL_ALIGN must be at a 2172 minimum of 2MB. As a result, only 10 bits of entropy are 2173 theoretically possible, but the implementations are further 2174 limited due to memory layouts. 2175 2176 If unsure, say Y. 2177 2178# Relocation on x86 needs some additional build support 2179config X86_NEED_RELOCS 2180 def_bool y 2181 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2182 2183config PHYSICAL_ALIGN 2184 hex "Alignment value to which kernel should be aligned" 2185 default "0x200000" 2186 range 0x2000 0x1000000 if X86_32 2187 range 0x200000 0x1000000 if X86_64 2188 ---help--- 2189 This value puts the alignment restrictions on physical address 2190 where kernel is loaded and run from. Kernel is compiled for an 2191 address which meets above alignment restriction. 2192 2193 If bootloader loads the kernel at a non-aligned address and 2194 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2195 address aligned to above value and run from there. 2196 2197 If bootloader loads the kernel at a non-aligned address and 2198 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2199 load address and decompress itself to the address it has been 2200 compiled for and run from there. The address for which kernel is 2201 compiled already meets above alignment restrictions. Hence the 2202 end result is that kernel runs from a physical address meeting 2203 above alignment restrictions. 2204 2205 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2206 this value must be a multiple of 0x200000. 2207 2208 Don't change this unless you know what you are doing. 2209 2210config DYNAMIC_MEMORY_LAYOUT 2211 bool 2212 ---help--- 2213 This option makes base addresses of vmalloc and vmemmap as well as 2214 __PAGE_OFFSET movable during boot. 2215 2216config RANDOMIZE_MEMORY 2217 bool "Randomize the kernel memory sections" 2218 depends on X86_64 2219 depends on RANDOMIZE_BASE 2220 select DYNAMIC_MEMORY_LAYOUT 2221 default RANDOMIZE_BASE 2222 ---help--- 2223 Randomizes the base virtual address of kernel memory sections 2224 (physical memory mapping, vmalloc & vmemmap). This security feature 2225 makes exploits relying on predictable memory locations less reliable. 2226 2227 The order of allocations remains unchanged. Entropy is generated in 2228 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2229 configuration have in average 30,000 different possible virtual 2230 addresses for each memory section. 2231 2232 If unsure, say Y. 2233 2234config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2235 hex "Physical memory mapping padding" if EXPERT 2236 depends on RANDOMIZE_MEMORY 2237 default "0xa" if MEMORY_HOTPLUG 2238 default "0x0" 2239 range 0x1 0x40 if MEMORY_HOTPLUG 2240 range 0x0 0x40 2241 ---help--- 2242 Define the padding in terabytes added to the existing physical 2243 memory size during kernel memory randomization. It is useful 2244 for memory hotplug support but reduces the entropy available for 2245 address randomization. 2246 2247 If unsure, leave at the default value. 2248 2249config HOTPLUG_CPU 2250 def_bool y 2251 depends on SMP 2252 2253config BOOTPARAM_HOTPLUG_CPU0 2254 bool "Set default setting of cpu0_hotpluggable" 2255 depends on HOTPLUG_CPU 2256 ---help--- 2257 Set whether default state of cpu0_hotpluggable is on or off. 2258 2259 Say Y here to enable CPU0 hotplug by default. If this switch 2260 is turned on, there is no need to give cpu0_hotplug kernel 2261 parameter and the CPU0 hotplug feature is enabled by default. 2262 2263 Please note: there are two known CPU0 dependencies if you want 2264 to enable the CPU0 hotplug feature either by this switch or by 2265 cpu0_hotplug kernel parameter. 2266 2267 First, resume from hibernate or suspend always starts from CPU0. 2268 So hibernate and suspend are prevented if CPU0 is offline. 2269 2270 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2271 offline if any interrupt can not migrate out of CPU0. There may 2272 be other CPU0 dependencies. 2273 2274 Please make sure the dependencies are under your control before 2275 you enable this feature. 2276 2277 Say N if you don't want to enable CPU0 hotplug feature by default. 2278 You still can enable the CPU0 hotplug feature at boot by kernel 2279 parameter cpu0_hotplug. 2280 2281config DEBUG_HOTPLUG_CPU0 2282 def_bool n 2283 prompt "Debug CPU0 hotplug" 2284 depends on HOTPLUG_CPU 2285 ---help--- 2286 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2287 soon as possible and boots up userspace with CPU0 offlined. User 2288 can online CPU0 back after boot time. 2289 2290 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2291 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2292 compilation or giving cpu0_hotplug kernel parameter at boot. 2293 2294 If unsure, say N. 2295 2296config COMPAT_VDSO 2297 def_bool n 2298 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2299 depends on COMPAT_32 2300 ---help--- 2301 Certain buggy versions of glibc will crash if they are 2302 presented with a 32-bit vDSO that is not mapped at the address 2303 indicated in its segment table. 2304 2305 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2306 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2307 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2308 the only released version with the bug, but OpenSUSE 9 2309 contains a buggy "glibc 2.3.2". 2310 2311 The symptom of the bug is that everything crashes on startup, saying: 2312 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2313 2314 Saying Y here changes the default value of the vdso32 boot 2315 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2316 This works around the glibc bug but hurts performance. 2317 2318 If unsure, say N: if you are compiling your own kernel, you 2319 are unlikely to be using a buggy version of glibc. 2320 2321choice 2322 prompt "vsyscall table for legacy applications" 2323 depends on X86_64 2324 default LEGACY_VSYSCALL_XONLY 2325 help 2326 Legacy user code that does not know how to find the vDSO expects 2327 to be able to issue three syscalls by calling fixed addresses in 2328 kernel space. Since this location is not randomized with ASLR, 2329 it can be used to assist security vulnerability exploitation. 2330 2331 This setting can be changed at boot time via the kernel command 2332 line parameter vsyscall=[emulate|xonly|none]. 2333 2334 On a system with recent enough glibc (2.14 or newer) and no 2335 static binaries, you can say None without a performance penalty 2336 to improve security. 2337 2338 If unsure, select "Emulate execution only". 2339 2340 config LEGACY_VSYSCALL_EMULATE 2341 bool "Full emulation" 2342 help 2343 The kernel traps and emulates calls into the fixed vsyscall 2344 address mapping. This makes the mapping non-executable, but 2345 it still contains readable known contents, which could be 2346 used in certain rare security vulnerability exploits. This 2347 configuration is recommended when using legacy userspace 2348 that still uses vsyscalls along with legacy binary 2349 instrumentation tools that require code to be readable. 2350 2351 An example of this type of legacy userspace is running 2352 Pin on an old binary that still uses vsyscalls. 2353 2354 config LEGACY_VSYSCALL_XONLY 2355 bool "Emulate execution only" 2356 help 2357 The kernel traps and emulates calls into the fixed vsyscall 2358 address mapping and does not allow reads. This 2359 configuration is recommended when userspace might use the 2360 legacy vsyscall area but support for legacy binary 2361 instrumentation of legacy code is not needed. It mitigates 2362 certain uses of the vsyscall area as an ASLR-bypassing 2363 buffer. 2364 2365 config LEGACY_VSYSCALL_NONE 2366 bool "None" 2367 help 2368 There will be no vsyscall mapping at all. This will 2369 eliminate any risk of ASLR bypass due to the vsyscall 2370 fixed address mapping. Attempts to use the vsyscalls 2371 will be reported to dmesg, so that either old or 2372 malicious userspace programs can be identified. 2373 2374endchoice 2375 2376config CMDLINE_BOOL 2377 bool "Built-in kernel command line" 2378 ---help--- 2379 Allow for specifying boot arguments to the kernel at 2380 build time. On some systems (e.g. embedded ones), it is 2381 necessary or convenient to provide some or all of the 2382 kernel boot arguments with the kernel itself (that is, 2383 to not rely on the boot loader to provide them.) 2384 2385 To compile command line arguments into the kernel, 2386 set this option to 'Y', then fill in the 2387 boot arguments in CONFIG_CMDLINE. 2388 2389 Systems with fully functional boot loaders (i.e. non-embedded) 2390 should leave this option set to 'N'. 2391 2392config CMDLINE 2393 string "Built-in kernel command string" 2394 depends on CMDLINE_BOOL 2395 default "" 2396 ---help--- 2397 Enter arguments here that should be compiled into the kernel 2398 image and used at boot time. If the boot loader provides a 2399 command line at boot time, it is appended to this string to 2400 form the full kernel command line, when the system boots. 2401 2402 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2403 change this behavior. 2404 2405 In most cases, the command line (whether built-in or provided 2406 by the boot loader) should specify the device for the root 2407 file system. 2408 2409config CMDLINE_OVERRIDE 2410 bool "Built-in command line overrides boot loader arguments" 2411 depends on CMDLINE_BOOL 2412 ---help--- 2413 Set this option to 'Y' to have the kernel ignore the boot loader 2414 command line, and use ONLY the built-in command line. 2415 2416 This is used to work around broken boot loaders. This should 2417 be set to 'N' under normal conditions. 2418 2419config MODIFY_LDT_SYSCALL 2420 bool "Enable the LDT (local descriptor table)" if EXPERT 2421 default y 2422 ---help--- 2423 Linux can allow user programs to install a per-process x86 2424 Local Descriptor Table (LDT) using the modify_ldt(2) system 2425 call. This is required to run 16-bit or segmented code such as 2426 DOSEMU or some Wine programs. It is also used by some very old 2427 threading libraries. 2428 2429 Enabling this feature adds a small amount of overhead to 2430 context switches and increases the low-level kernel attack 2431 surface. Disabling it removes the modify_ldt(2) system call. 2432 2433 Saying 'N' here may make sense for embedded or server kernels. 2434 2435source "kernel/livepatch/Kconfig" 2436 2437endmenu 2438 2439config ARCH_HAS_ADD_PAGES 2440 def_bool y 2441 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2442 2443config ARCH_ENABLE_MEMORY_HOTPLUG 2444 def_bool y 2445 depends on X86_64 || (X86_32 && HIGHMEM) 2446 2447config ARCH_ENABLE_MEMORY_HOTREMOVE 2448 def_bool y 2449 depends on MEMORY_HOTPLUG 2450 2451config USE_PERCPU_NUMA_NODE_ID 2452 def_bool y 2453 depends on NUMA 2454 2455config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2456 def_bool y 2457 depends on X86_64 || X86_PAE 2458 2459config ARCH_ENABLE_HUGEPAGE_MIGRATION 2460 def_bool y 2461 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2462 2463config ARCH_ENABLE_THP_MIGRATION 2464 def_bool y 2465 depends on X86_64 && TRANSPARENT_HUGEPAGE 2466 2467menu "Power management and ACPI options" 2468 2469config ARCH_HIBERNATION_HEADER 2470 def_bool y 2471 depends on HIBERNATION 2472 2473source "kernel/power/Kconfig" 2474 2475source "drivers/acpi/Kconfig" 2476 2477source "drivers/sfi/Kconfig" 2478 2479config X86_APM_BOOT 2480 def_bool y 2481 depends on APM 2482 2483menuconfig APM 2484 tristate "APM (Advanced Power Management) BIOS support" 2485 depends on X86_32 && PM_SLEEP 2486 ---help--- 2487 APM is a BIOS specification for saving power using several different 2488 techniques. This is mostly useful for battery powered laptops with 2489 APM compliant BIOSes. If you say Y here, the system time will be 2490 reset after a RESUME operation, the /proc/apm device will provide 2491 battery status information, and user-space programs will receive 2492 notification of APM "events" (e.g. battery status change). 2493 2494 If you select "Y" here, you can disable actual use of the APM 2495 BIOS by passing the "apm=off" option to the kernel at boot time. 2496 2497 Note that the APM support is almost completely disabled for 2498 machines with more than one CPU. 2499 2500 In order to use APM, you will need supporting software. For location 2501 and more information, read <file:Documentation/power/apm-acpi.rst> 2502 and the Battery Powered Linux mini-HOWTO, available from 2503 <http://www.tldp.org/docs.html#howto>. 2504 2505 This driver does not spin down disk drives (see the hdparm(8) 2506 manpage ("man 8 hdparm") for that), and it doesn't turn off 2507 VESA-compliant "green" monitors. 2508 2509 This driver does not support the TI 4000M TravelMate and the ACER 2510 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2511 desktop machines also don't have compliant BIOSes, and this driver 2512 may cause those machines to panic during the boot phase. 2513 2514 Generally, if you don't have a battery in your machine, there isn't 2515 much point in using this driver and you should say N. If you get 2516 random kernel OOPSes or reboots that don't seem to be related to 2517 anything, try disabling/enabling this option (or disabling/enabling 2518 APM in your BIOS). 2519 2520 Some other things you should try when experiencing seemingly random, 2521 "weird" problems: 2522 2523 1) make sure that you have enough swap space and that it is 2524 enabled. 2525 2) pass the "no-hlt" option to the kernel 2526 3) switch on floating point emulation in the kernel and pass 2527 the "no387" option to the kernel 2528 4) pass the "floppy=nodma" option to the kernel 2529 5) pass the "mem=4M" option to the kernel (thereby disabling 2530 all but the first 4 MB of RAM) 2531 6) make sure that the CPU is not over clocked. 2532 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2533 8) disable the cache from your BIOS settings 2534 9) install a fan for the video card or exchange video RAM 2535 10) install a better fan for the CPU 2536 11) exchange RAM chips 2537 12) exchange the motherboard. 2538 2539 To compile this driver as a module, choose M here: the 2540 module will be called apm. 2541 2542if APM 2543 2544config APM_IGNORE_USER_SUSPEND 2545 bool "Ignore USER SUSPEND" 2546 ---help--- 2547 This option will ignore USER SUSPEND requests. On machines with a 2548 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2549 series notebooks, it is necessary to say Y because of a BIOS bug. 2550 2551config APM_DO_ENABLE 2552 bool "Enable PM at boot time" 2553 ---help--- 2554 Enable APM features at boot time. From page 36 of the APM BIOS 2555 specification: "When disabled, the APM BIOS does not automatically 2556 power manage devices, enter the Standby State, enter the Suspend 2557 State, or take power saving steps in response to CPU Idle calls." 2558 This driver will make CPU Idle calls when Linux is idle (unless this 2559 feature is turned off -- see "Do CPU IDLE calls", below). This 2560 should always save battery power, but more complicated APM features 2561 will be dependent on your BIOS implementation. You may need to turn 2562 this option off if your computer hangs at boot time when using APM 2563 support, or if it beeps continuously instead of suspending. Turn 2564 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2565 T400CDT. This is off by default since most machines do fine without 2566 this feature. 2567 2568config APM_CPU_IDLE 2569 depends on CPU_IDLE 2570 bool "Make CPU Idle calls when idle" 2571 ---help--- 2572 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2573 On some machines, this can activate improved power savings, such as 2574 a slowed CPU clock rate, when the machine is idle. These idle calls 2575 are made after the idle loop has run for some length of time (e.g., 2576 333 mS). On some machines, this will cause a hang at boot time or 2577 whenever the CPU becomes idle. (On machines with more than one CPU, 2578 this option does nothing.) 2579 2580config APM_DISPLAY_BLANK 2581 bool "Enable console blanking using APM" 2582 ---help--- 2583 Enable console blanking using the APM. Some laptops can use this to 2584 turn off the LCD backlight when the screen blanker of the Linux 2585 virtual console blanks the screen. Note that this is only used by 2586 the virtual console screen blanker, and won't turn off the backlight 2587 when using the X Window system. This also doesn't have anything to 2588 do with your VESA-compliant power-saving monitor. Further, this 2589 option doesn't work for all laptops -- it might not turn off your 2590 backlight at all, or it might print a lot of errors to the console, 2591 especially if you are using gpm. 2592 2593config APM_ALLOW_INTS 2594 bool "Allow interrupts during APM BIOS calls" 2595 ---help--- 2596 Normally we disable external interrupts while we are making calls to 2597 the APM BIOS as a measure to lessen the effects of a badly behaving 2598 BIOS implementation. The BIOS should reenable interrupts if it 2599 needs to. Unfortunately, some BIOSes do not -- especially those in 2600 many of the newer IBM Thinkpads. If you experience hangs when you 2601 suspend, try setting this to Y. Otherwise, say N. 2602 2603endif # APM 2604 2605source "drivers/cpufreq/Kconfig" 2606 2607source "drivers/cpuidle/Kconfig" 2608 2609source "drivers/idle/Kconfig" 2610 2611endmenu 2612 2613 2614menu "Bus options (PCI etc.)" 2615 2616choice 2617 prompt "PCI access mode" 2618 depends on X86_32 && PCI 2619 default PCI_GOANY 2620 ---help--- 2621 On PCI systems, the BIOS can be used to detect the PCI devices and 2622 determine their configuration. However, some old PCI motherboards 2623 have BIOS bugs and may crash if this is done. Also, some embedded 2624 PCI-based systems don't have any BIOS at all. Linux can also try to 2625 detect the PCI hardware directly without using the BIOS. 2626 2627 With this option, you can specify how Linux should detect the 2628 PCI devices. If you choose "BIOS", the BIOS will be used, 2629 if you choose "Direct", the BIOS won't be used, and if you 2630 choose "MMConfig", then PCI Express MMCONFIG will be used. 2631 If you choose "Any", the kernel will try MMCONFIG, then the 2632 direct access method and falls back to the BIOS if that doesn't 2633 work. If unsure, go with the default, which is "Any". 2634 2635config PCI_GOBIOS 2636 bool "BIOS" 2637 2638config PCI_GOMMCONFIG 2639 bool "MMConfig" 2640 2641config PCI_GODIRECT 2642 bool "Direct" 2643 2644config PCI_GOOLPC 2645 bool "OLPC XO-1" 2646 depends on OLPC 2647 2648config PCI_GOANY 2649 bool "Any" 2650 2651endchoice 2652 2653config PCI_BIOS 2654 def_bool y 2655 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2656 2657# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2658config PCI_DIRECT 2659 def_bool y 2660 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2661 2662config PCI_MMCONFIG 2663 bool "Support mmconfig PCI config space access" if X86_64 2664 default y 2665 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2666 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2667 2668config PCI_OLPC 2669 def_bool y 2670 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2671 2672config PCI_XEN 2673 def_bool y 2674 depends on PCI && XEN 2675 select SWIOTLB_XEN 2676 2677config MMCONF_FAM10H 2678 def_bool y 2679 depends on X86_64 && PCI_MMCONFIG && ACPI 2680 2681config PCI_CNB20LE_QUIRK 2682 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2683 depends on PCI 2684 help 2685 Read the PCI windows out of the CNB20LE host bridge. This allows 2686 PCI hotplug to work on systems with the CNB20LE chipset which do 2687 not have ACPI. 2688 2689 There's no public spec for this chipset, and this functionality 2690 is known to be incomplete. 2691 2692 You should say N unless you know you need this. 2693 2694config ISA_BUS 2695 bool "ISA bus support on modern systems" if EXPERT 2696 help 2697 Expose ISA bus device drivers and options available for selection and 2698 configuration. Enable this option if your target machine has an ISA 2699 bus. ISA is an older system, displaced by PCI and newer bus 2700 architectures -- if your target machine is modern, it probably does 2701 not have an ISA bus. 2702 2703 If unsure, say N. 2704 2705# x86_64 have no ISA slots, but can have ISA-style DMA. 2706config ISA_DMA_API 2707 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2708 default y 2709 help 2710 Enables ISA-style DMA support for devices requiring such controllers. 2711 If unsure, say Y. 2712 2713if X86_32 2714 2715config ISA 2716 bool "ISA support" 2717 ---help--- 2718 Find out whether you have ISA slots on your motherboard. ISA is the 2719 name of a bus system, i.e. the way the CPU talks to the other stuff 2720 inside your box. Other bus systems are PCI, EISA, MicroChannel 2721 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2722 newer boards don't support it. If you have ISA, say Y, otherwise N. 2723 2724config SCx200 2725 tristate "NatSemi SCx200 support" 2726 ---help--- 2727 This provides basic support for National Semiconductor's 2728 (now AMD's) Geode processors. The driver probes for the 2729 PCI-IDs of several on-chip devices, so its a good dependency 2730 for other scx200_* drivers. 2731 2732 If compiled as a module, the driver is named scx200. 2733 2734config SCx200HR_TIMER 2735 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2736 depends on SCx200 2737 default y 2738 ---help--- 2739 This driver provides a clocksource built upon the on-chip 2740 27MHz high-resolution timer. Its also a workaround for 2741 NSC Geode SC-1100's buggy TSC, which loses time when the 2742 processor goes idle (as is done by the scheduler). The 2743 other workaround is idle=poll boot option. 2744 2745config OLPC 2746 bool "One Laptop Per Child support" 2747 depends on !X86_PAE 2748 select GPIOLIB 2749 select OF 2750 select OF_PROMTREE 2751 select IRQ_DOMAIN 2752 select OLPC_EC 2753 ---help--- 2754 Add support for detecting the unique features of the OLPC 2755 XO hardware. 2756 2757config OLPC_XO1_PM 2758 bool "OLPC XO-1 Power Management" 2759 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2760 ---help--- 2761 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2762 2763config OLPC_XO1_RTC 2764 bool "OLPC XO-1 Real Time Clock" 2765 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2766 ---help--- 2767 Add support for the XO-1 real time clock, which can be used as a 2768 programmable wakeup source. 2769 2770config OLPC_XO1_SCI 2771 bool "OLPC XO-1 SCI extras" 2772 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2773 depends on INPUT=y 2774 select POWER_SUPPLY 2775 ---help--- 2776 Add support for SCI-based features of the OLPC XO-1 laptop: 2777 - EC-driven system wakeups 2778 - Power button 2779 - Ebook switch 2780 - Lid switch 2781 - AC adapter status updates 2782 - Battery status updates 2783 2784config OLPC_XO15_SCI 2785 bool "OLPC XO-1.5 SCI extras" 2786 depends on OLPC && ACPI 2787 select POWER_SUPPLY 2788 ---help--- 2789 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2790 - EC-driven system wakeups 2791 - AC adapter status updates 2792 - Battery status updates 2793 2794config ALIX 2795 bool "PCEngines ALIX System Support (LED setup)" 2796 select GPIOLIB 2797 ---help--- 2798 This option enables system support for the PCEngines ALIX. 2799 At present this just sets up LEDs for GPIO control on 2800 ALIX2/3/6 boards. However, other system specific setup should 2801 get added here. 2802 2803 Note: You must still enable the drivers for GPIO and LED support 2804 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2805 2806 Note: You have to set alix.force=1 for boards with Award BIOS. 2807 2808config NET5501 2809 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2810 select GPIOLIB 2811 ---help--- 2812 This option enables system support for the Soekris Engineering net5501. 2813 2814config GEOS 2815 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2816 select GPIOLIB 2817 depends on DMI 2818 ---help--- 2819 This option enables system support for the Traverse Technologies GEOS. 2820 2821config TS5500 2822 bool "Technologic Systems TS-5500 platform support" 2823 depends on MELAN 2824 select CHECK_SIGNATURE 2825 select NEW_LEDS 2826 select LEDS_CLASS 2827 ---help--- 2828 This option enables system support for the Technologic Systems TS-5500. 2829 2830endif # X86_32 2831 2832config AMD_NB 2833 def_bool y 2834 depends on CPU_SUP_AMD && PCI 2835 2836config X86_SYSFB 2837 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2838 help 2839 Firmwares often provide initial graphics framebuffers so the BIOS, 2840 bootloader or kernel can show basic video-output during boot for 2841 user-guidance and debugging. Historically, x86 used the VESA BIOS 2842 Extensions and EFI-framebuffers for this, which are mostly limited 2843 to x86. 2844 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2845 framebuffers so the new generic system-framebuffer drivers can be 2846 used on x86. If the framebuffer is not compatible with the generic 2847 modes, it is advertised as fallback platform framebuffer so legacy 2848 drivers like efifb, vesafb and uvesafb can pick it up. 2849 If this option is not selected, all system framebuffers are always 2850 marked as fallback platform framebuffers as usual. 2851 2852 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2853 not be able to pick up generic system framebuffers if this option 2854 is selected. You are highly encouraged to enable simplefb as 2855 replacement if you select this option. simplefb can correctly deal 2856 with generic system framebuffers. But you should still keep vesafb 2857 and others enabled as fallback if a system framebuffer is 2858 incompatible with simplefb. 2859 2860 If unsure, say Y. 2861 2862endmenu 2863 2864 2865menu "Binary Emulations" 2866 2867config IA32_EMULATION 2868 bool "IA32 Emulation" 2869 depends on X86_64 2870 select ARCH_WANT_OLD_COMPAT_IPC 2871 select BINFMT_ELF 2872 select COMPAT_BINFMT_ELF 2873 select COMPAT_OLD_SIGACTION 2874 ---help--- 2875 Include code to run legacy 32-bit programs under a 2876 64-bit kernel. You should likely turn this on, unless you're 2877 100% sure that you don't have any 32-bit programs left. 2878 2879config IA32_AOUT 2880 tristate "IA32 a.out support" 2881 depends on IA32_EMULATION 2882 depends on BROKEN 2883 ---help--- 2884 Support old a.out binaries in the 32bit emulation. 2885 2886config X86_X32 2887 bool "x32 ABI for 64-bit mode" 2888 depends on X86_64 2889 ---help--- 2890 Include code to run binaries for the x32 native 32-bit ABI 2891 for 64-bit processors. An x32 process gets access to the 2892 full 64-bit register file and wide data path while leaving 2893 pointers at 32 bits for smaller memory footprint. 2894 2895 You will need a recent binutils (2.22 or later) with 2896 elf32_x86_64 support enabled to compile a kernel with this 2897 option set. 2898 2899config COMPAT_32 2900 def_bool y 2901 depends on IA32_EMULATION || X86_32 2902 select HAVE_UID16 2903 select OLD_SIGSUSPEND3 2904 2905config COMPAT 2906 def_bool y 2907 depends on IA32_EMULATION || X86_X32 2908 2909if COMPAT 2910config COMPAT_FOR_U64_ALIGNMENT 2911 def_bool y 2912 2913config SYSVIPC_COMPAT 2914 def_bool y 2915 depends on SYSVIPC 2916endif 2917 2918endmenu 2919 2920 2921config HAVE_ATOMIC_IOMAP 2922 def_bool y 2923 depends on X86_32 2924 2925config X86_DEV_DMA_OPS 2926 bool 2927 2928source "drivers/firmware/Kconfig" 2929 2930source "arch/x86/kvm/Kconfig" 2931