1# SPDX-License-Identifier: GPL-2.0 2# Select 32 or 64 bit 3config 64BIT 4 bool "64-bit kernel" if "$(ARCH)" = "x86" 5 default "$(ARCH)" != "i386" 6 ---help--- 7 Say yes to build a 64-bit kernel - formerly known as x86_64 8 Say no to build a 32-bit kernel - formerly known as i386 9 10config X86_32 11 def_bool y 12 depends on !64BIT 13 # Options that are inherently 32-bit kernel only: 14 select ARCH_WANT_IPC_PARSE_VERSION 15 select CLKSRC_I8253 16 select CLONE_BACKWARDS 17 select HAVE_DEBUG_STACKOVERFLOW 18 select MODULES_USE_ELF_REL 19 select OLD_SIGACTION 20 select GENERIC_VDSO_32 21 22config X86_64 23 def_bool y 24 depends on 64BIT 25 # Options that are inherently 64-bit kernel only: 26 select ARCH_HAS_GIGANTIC_PAGE 27 select ARCH_SUPPORTS_INT128 28 select ARCH_USE_CMPXCHG_LOCKREF 29 select HAVE_ARCH_SOFT_DIRTY 30 select MODULES_USE_ELF_RELA 31 select NEED_DMA_MAP_STATE 32 select SWIOTLB 33 select ARCH_HAS_SYSCALL_WRAPPER 34 35config FORCE_DYNAMIC_FTRACE 36 def_bool y 37 depends on X86_32 38 depends on FUNCTION_TRACER 39 select DYNAMIC_FTRACE 40 help 41 We keep the static function tracing (!DYNAMIC_FTRACE) around 42 in order to test the non static function tracing in the 43 generic code, as other architectures still use it. But we 44 only need to keep it around for x86_64. No need to keep it 45 for x86_32. For x86_32, force DYNAMIC_FTRACE. 46# 47# Arch settings 48# 49# ( Note that options that are marked 'if X86_64' could in principle be 50# ported to 32-bit as well. ) 51# 52config X86 53 def_bool y 54 # 55 # Note: keep this list sorted alphabetically 56 # 57 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 58 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 59 select ARCH_32BIT_OFF_T if X86_32 60 select ARCH_CLOCKSOURCE_DATA 61 select ARCH_CLOCKSOURCE_INIT 62 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 63 select ARCH_HAS_DEBUG_VIRTUAL 64 select ARCH_HAS_DEVMEM_IS_ALLOWED 65 select ARCH_HAS_ELF_RANDOMIZE 66 select ARCH_HAS_FAST_MULTIPLIER 67 select ARCH_HAS_FILTER_PGPROT 68 select ARCH_HAS_FORTIFY_SOURCE 69 select ARCH_HAS_GCOV_PROFILE_ALL 70 select ARCH_HAS_KCOV if X86_64 71 select ARCH_HAS_MEMBARRIER_SYNC_CORE 72 select ARCH_HAS_PMEM_API if X86_64 73 select ARCH_HAS_PTE_DEVMAP if X86_64 74 select ARCH_HAS_PTE_SPECIAL 75 select ARCH_HAS_REFCOUNT 76 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 77 select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE 78 select ARCH_HAS_SET_MEMORY 79 select ARCH_HAS_SET_DIRECT_MAP 80 select ARCH_HAS_STRICT_KERNEL_RWX 81 select ARCH_HAS_STRICT_MODULE_RWX 82 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 83 select ARCH_HAS_UBSAN_SANITIZE_ALL 84 select ARCH_HAVE_NMI_SAFE_CMPXCHG 85 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 86 select ARCH_MIGHT_HAVE_PC_PARPORT 87 select ARCH_MIGHT_HAVE_PC_SERIO 88 select ARCH_STACKWALK 89 select ARCH_SUPPORTS_ACPI 90 select ARCH_SUPPORTS_ATOMIC_RMW 91 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 92 select ARCH_USE_BUILTIN_BSWAP 93 select ARCH_USE_QUEUED_RWLOCKS 94 select ARCH_USE_QUEUED_SPINLOCKS 95 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 96 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 97 select ARCH_WANT_HUGE_PMD_SHARE 98 select ARCH_WANTS_THP_SWAP if X86_64 99 select BUILDTIME_EXTABLE_SORT 100 select CLKEVT_I8253 101 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 102 select CLOCKSOURCE_WATCHDOG 103 select DCACHE_WORD_ACCESS 104 select EDAC_ATOMIC_SCRUB 105 select EDAC_SUPPORT 106 select GENERIC_CLOCKEVENTS 107 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 108 select GENERIC_CLOCKEVENTS_MIN_ADJUST 109 select GENERIC_CMOS_UPDATE 110 select GENERIC_CPU_AUTOPROBE 111 select GENERIC_CPU_VULNERABILITIES 112 select GENERIC_EARLY_IOREMAP 113 select GENERIC_FIND_FIRST_BIT 114 select GENERIC_IOMAP 115 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 116 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 117 select GENERIC_IRQ_MIGRATION if SMP 118 select GENERIC_IRQ_PROBE 119 select GENERIC_IRQ_RESERVATION_MODE 120 select GENERIC_IRQ_SHOW 121 select GENERIC_PENDING_IRQ if SMP 122 select GENERIC_SMP_IDLE_THREAD 123 select GENERIC_STRNCPY_FROM_USER 124 select GENERIC_STRNLEN_USER 125 select GENERIC_TIME_VSYSCALL 126 select GENERIC_GETTIMEOFDAY 127 select GUP_GET_PTE_LOW_HIGH if X86_PAE 128 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 129 select HAVE_ACPI_APEI if ACPI 130 select HAVE_ACPI_APEI_NMI if ACPI 131 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 132 select HAVE_ARCH_AUDITSYSCALL 133 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 134 select HAVE_ARCH_JUMP_LABEL 135 select HAVE_ARCH_JUMP_LABEL_RELATIVE 136 select HAVE_ARCH_KASAN if X86_64 137 select HAVE_ARCH_KGDB 138 select HAVE_ARCH_MMAP_RND_BITS if MMU 139 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 140 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 141 select HAVE_ARCH_PREL32_RELOCATIONS 142 select HAVE_ARCH_SECCOMP_FILTER 143 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 144 select HAVE_ARCH_STACKLEAK 145 select HAVE_ARCH_TRACEHOOK 146 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 147 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 148 select HAVE_ARCH_VMAP_STACK if X86_64 149 select HAVE_ARCH_WITHIN_STACK_FRAMES 150 select HAVE_CMPXCHG_DOUBLE 151 select HAVE_CMPXCHG_LOCAL 152 select HAVE_CONTEXT_TRACKING if X86_64 153 select HAVE_COPY_THREAD_TLS 154 select HAVE_C_RECORDMCOUNT 155 select HAVE_DEBUG_KMEMLEAK 156 select HAVE_DMA_CONTIGUOUS 157 select HAVE_DYNAMIC_FTRACE 158 select HAVE_DYNAMIC_FTRACE_WITH_REGS 159 select HAVE_EBPF_JIT 160 select HAVE_EFFICIENT_UNALIGNED_ACCESS 161 select HAVE_EISA 162 select HAVE_EXIT_THREAD 163 select HAVE_FAST_GUP 164 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 165 select HAVE_FTRACE_MCOUNT_RECORD 166 select HAVE_FUNCTION_GRAPH_TRACER 167 select HAVE_FUNCTION_TRACER 168 select HAVE_GCC_PLUGINS 169 select HAVE_HW_BREAKPOINT 170 select HAVE_IDE 171 select HAVE_IOREMAP_PROT 172 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 173 select HAVE_IRQ_TIME_ACCOUNTING 174 select HAVE_KERNEL_BZIP2 175 select HAVE_KERNEL_GZIP 176 select HAVE_KERNEL_LZ4 177 select HAVE_KERNEL_LZMA 178 select HAVE_KERNEL_LZO 179 select HAVE_KERNEL_XZ 180 select HAVE_KPROBES 181 select HAVE_KPROBES_ON_FTRACE 182 select HAVE_FUNCTION_ERROR_INJECTION 183 select HAVE_KRETPROBES 184 select HAVE_KVM 185 select HAVE_LIVEPATCH if X86_64 186 select HAVE_MEMBLOCK_NODE_MAP 187 select HAVE_MIXED_BREAKPOINTS_REGS 188 select HAVE_MOD_ARCH_SPECIFIC 189 select HAVE_MOVE_PMD 190 select HAVE_NMI 191 select HAVE_OPROFILE 192 select HAVE_OPTPROBES 193 select HAVE_PCSPKR_PLATFORM 194 select HAVE_PERF_EVENTS 195 select HAVE_PERF_EVENTS_NMI 196 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 197 select HAVE_PCI 198 select HAVE_PERF_REGS 199 select HAVE_PERF_USER_STACK_DUMP 200 select HAVE_RCU_TABLE_FREE if PARAVIRT 201 select HAVE_REGS_AND_STACK_ACCESS_API 202 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 203 select HAVE_FUNCTION_ARG_ACCESS_API 204 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 205 select HAVE_STACK_VALIDATION if X86_64 206 select HAVE_RSEQ 207 select HAVE_SYSCALL_TRACEPOINTS 208 select HAVE_UNSTABLE_SCHED_CLOCK 209 select HAVE_USER_RETURN_NOTIFIER 210 select HAVE_GENERIC_VDSO 211 select HOTPLUG_SMT if SMP 212 select IRQ_FORCED_THREADING 213 select NEED_SG_DMA_LENGTH 214 select PCI_DOMAINS if PCI 215 select PCI_LOCKLESS_CONFIG if PCI 216 select PERF_EVENTS 217 select RTC_LIB 218 select RTC_MC146818_LIB 219 select SPARSE_IRQ 220 select SRCU 221 select SYSCTL_EXCEPTION_TRACE 222 select THREAD_INFO_IN_TASK 223 select USER_STACKTRACE_SUPPORT 224 select VIRT_TO_BUS 225 select X86_FEATURE_NAMES if PROC_FS 226 select PROC_PID_ARCH_STATUS if PROC_FS 227 228config INSTRUCTION_DECODER 229 def_bool y 230 depends on KPROBES || PERF_EVENTS || UPROBES 231 232config OUTPUT_FORMAT 233 string 234 default "elf32-i386" if X86_32 235 default "elf64-x86-64" if X86_64 236 237config ARCH_DEFCONFIG 238 string 239 default "arch/x86/configs/i386_defconfig" if X86_32 240 default "arch/x86/configs/x86_64_defconfig" if X86_64 241 242config LOCKDEP_SUPPORT 243 def_bool y 244 245config STACKTRACE_SUPPORT 246 def_bool y 247 248config MMU 249 def_bool y 250 251config ARCH_MMAP_RND_BITS_MIN 252 default 28 if 64BIT 253 default 8 254 255config ARCH_MMAP_RND_BITS_MAX 256 default 32 if 64BIT 257 default 16 258 259config ARCH_MMAP_RND_COMPAT_BITS_MIN 260 default 8 261 262config ARCH_MMAP_RND_COMPAT_BITS_MAX 263 default 16 264 265config SBUS 266 bool 267 268config GENERIC_ISA_DMA 269 def_bool y 270 depends on ISA_DMA_API 271 272config GENERIC_BUG 273 def_bool y 274 depends on BUG 275 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 276 277config GENERIC_BUG_RELATIVE_POINTERS 278 bool 279 280config ARCH_MAY_HAVE_PC_FDC 281 def_bool y 282 depends on ISA_DMA_API 283 284config GENERIC_CALIBRATE_DELAY 285 def_bool y 286 287config ARCH_HAS_CPU_RELAX 288 def_bool y 289 290config ARCH_HAS_CACHE_LINE_SIZE 291 def_bool y 292 293config ARCH_HAS_FILTER_PGPROT 294 def_bool y 295 296config HAVE_SETUP_PER_CPU_AREA 297 def_bool y 298 299config NEED_PER_CPU_EMBED_FIRST_CHUNK 300 def_bool y 301 302config NEED_PER_CPU_PAGE_FIRST_CHUNK 303 def_bool y 304 305config ARCH_HIBERNATION_POSSIBLE 306 def_bool y 307 308config ARCH_SUSPEND_POSSIBLE 309 def_bool y 310 311config ARCH_WANT_GENERAL_HUGETLB 312 def_bool y 313 314config ZONE_DMA32 315 def_bool y if X86_64 316 317config AUDIT_ARCH 318 def_bool y if X86_64 319 320config ARCH_SUPPORTS_DEBUG_PAGEALLOC 321 def_bool y 322 323config KASAN_SHADOW_OFFSET 324 hex 325 depends on KASAN 326 default 0xdffffc0000000000 327 328config HAVE_INTEL_TXT 329 def_bool y 330 depends on INTEL_IOMMU && ACPI 331 332config X86_32_SMP 333 def_bool y 334 depends on X86_32 && SMP 335 336config X86_64_SMP 337 def_bool y 338 depends on X86_64 && SMP 339 340config X86_32_LAZY_GS 341 def_bool y 342 depends on X86_32 && !STACKPROTECTOR 343 344config ARCH_SUPPORTS_UPROBES 345 def_bool y 346 347config FIX_EARLYCON_MEM 348 def_bool y 349 350config DYNAMIC_PHYSICAL_MASK 351 bool 352 353config PGTABLE_LEVELS 354 int 355 default 5 if X86_5LEVEL 356 default 4 if X86_64 357 default 3 if X86_PAE 358 default 2 359 360config CC_HAS_SANE_STACKPROTECTOR 361 bool 362 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 363 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 364 help 365 We have to make sure stack protector is unconditionally disabled if 366 the compiler produces broken code. 367 368menu "Processor type and features" 369 370config ZONE_DMA 371 bool "DMA memory allocation support" if EXPERT 372 default y 373 help 374 DMA memory allocation support allows devices with less than 32-bit 375 addressing to allocate within the first 16MB of address space. 376 Disable if no such devices will be used. 377 378 If unsure, say Y. 379 380config SMP 381 bool "Symmetric multi-processing support" 382 ---help--- 383 This enables support for systems with more than one CPU. If you have 384 a system with only one CPU, say N. If you have a system with more 385 than one CPU, say Y. 386 387 If you say N here, the kernel will run on uni- and multiprocessor 388 machines, but will use only one CPU of a multiprocessor machine. If 389 you say Y here, the kernel will run on many, but not all, 390 uniprocessor machines. On a uniprocessor machine, the kernel 391 will run faster if you say N here. 392 393 Note that if you say Y here and choose architecture "586" or 394 "Pentium" under "Processor family", the kernel will not work on 486 395 architectures. Similarly, multiprocessor kernels for the "PPro" 396 architecture may not work on all Pentium based boards. 397 398 People using multiprocessor machines who say Y here should also say 399 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 400 Management" code will be disabled if you say Y here. 401 402 See also <file:Documentation/x86/i386/IO-APIC.rst>, 403 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 404 <http://www.tldp.org/docs.html#howto>. 405 406 If you don't know what to do here, say N. 407 408config X86_FEATURE_NAMES 409 bool "Processor feature human-readable names" if EMBEDDED 410 default y 411 ---help--- 412 This option compiles in a table of x86 feature bits and corresponding 413 names. This is required to support /proc/cpuinfo and a few kernel 414 messages. You can disable this to save space, at the expense of 415 making those few kernel messages show numeric feature bits instead. 416 417 If in doubt, say Y. 418 419config X86_X2APIC 420 bool "Support x2apic" 421 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 422 ---help--- 423 This enables x2apic support on CPUs that have this feature. 424 425 This allows 32-bit apic IDs (so it can support very large systems), 426 and accesses the local apic via MSRs not via mmio. 427 428 If you don't know what to do here, say N. 429 430config X86_MPPARSE 431 bool "Enable MPS table" if ACPI || SFI 432 default y 433 depends on X86_LOCAL_APIC 434 ---help--- 435 For old smp systems that do not have proper acpi support. Newer systems 436 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 437 438config GOLDFISH 439 def_bool y 440 depends on X86_GOLDFISH 441 442config RETPOLINE 443 bool "Avoid speculative indirect branches in kernel" 444 default y 445 select STACK_VALIDATION if HAVE_STACK_VALIDATION 446 help 447 Compile kernel with the retpoline compiler options to guard against 448 kernel-to-user data leaks by avoiding speculative indirect 449 branches. Requires a compiler with -mindirect-branch=thunk-extern 450 support for full protection. The kernel may run slower. 451 452config X86_CPU_RESCTRL 453 bool "x86 CPU resource control support" 454 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 455 select KERNFS 456 help 457 Enable x86 CPU resource control support. 458 459 Provide support for the allocation and monitoring of system resources 460 usage by the CPU. 461 462 Intel calls this Intel Resource Director Technology 463 (Intel(R) RDT). More information about RDT can be found in the 464 Intel x86 Architecture Software Developer Manual. 465 466 AMD calls this AMD Platform Quality of Service (AMD QoS). 467 More information about AMD QoS can be found in the AMD64 Technology 468 Platform Quality of Service Extensions manual. 469 470 Say N if unsure. 471 472if X86_32 473config X86_BIGSMP 474 bool "Support for big SMP systems with more than 8 CPUs" 475 depends on SMP 476 ---help--- 477 This option is needed for the systems that have more than 8 CPUs 478 479config X86_EXTENDED_PLATFORM 480 bool "Support for extended (non-PC) x86 platforms" 481 default y 482 ---help--- 483 If you disable this option then the kernel will only support 484 standard PC platforms. (which covers the vast majority of 485 systems out there.) 486 487 If you enable this option then you'll be able to select support 488 for the following (non-PC) 32 bit x86 platforms: 489 Goldfish (Android emulator) 490 AMD Elan 491 RDC R-321x SoC 492 SGI 320/540 (Visual Workstation) 493 STA2X11-based (e.g. Northville) 494 Moorestown MID devices 495 496 If you have one of these systems, or if you want to build a 497 generic distribution kernel, say Y here - otherwise say N. 498endif 499 500if X86_64 501config X86_EXTENDED_PLATFORM 502 bool "Support for extended (non-PC) x86 platforms" 503 default y 504 ---help--- 505 If you disable this option then the kernel will only support 506 standard PC platforms. (which covers the vast majority of 507 systems out there.) 508 509 If you enable this option then you'll be able to select support 510 for the following (non-PC) 64 bit x86 platforms: 511 Numascale NumaChip 512 ScaleMP vSMP 513 SGI Ultraviolet 514 515 If you have one of these systems, or if you want to build a 516 generic distribution kernel, say Y here - otherwise say N. 517endif 518# This is an alphabetically sorted list of 64 bit extended platforms 519# Please maintain the alphabetic order if and when there are additions 520config X86_NUMACHIP 521 bool "Numascale NumaChip" 522 depends on X86_64 523 depends on X86_EXTENDED_PLATFORM 524 depends on NUMA 525 depends on SMP 526 depends on X86_X2APIC 527 depends on PCI_MMCONFIG 528 ---help--- 529 Adds support for Numascale NumaChip large-SMP systems. Needed to 530 enable more than ~168 cores. 531 If you don't have one of these, you should say N here. 532 533config X86_VSMP 534 bool "ScaleMP vSMP" 535 select HYPERVISOR_GUEST 536 select PARAVIRT 537 depends on X86_64 && PCI 538 depends on X86_EXTENDED_PLATFORM 539 depends on SMP 540 ---help--- 541 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 542 supposed to run on these EM64T-based machines. Only choose this option 543 if you have one of these machines. 544 545config X86_UV 546 bool "SGI Ultraviolet" 547 depends on X86_64 548 depends on X86_EXTENDED_PLATFORM 549 depends on NUMA 550 depends on EFI 551 depends on X86_X2APIC 552 depends on PCI 553 ---help--- 554 This option is needed in order to support SGI Ultraviolet systems. 555 If you don't have one of these, you should say N here. 556 557# Following is an alphabetically sorted list of 32 bit extended platforms 558# Please maintain the alphabetic order if and when there are additions 559 560config X86_GOLDFISH 561 bool "Goldfish (Virtual Platform)" 562 depends on X86_EXTENDED_PLATFORM 563 ---help--- 564 Enable support for the Goldfish virtual platform used primarily 565 for Android development. Unless you are building for the Android 566 Goldfish emulator say N here. 567 568config X86_INTEL_CE 569 bool "CE4100 TV platform" 570 depends on PCI 571 depends on PCI_GODIRECT 572 depends on X86_IO_APIC 573 depends on X86_32 574 depends on X86_EXTENDED_PLATFORM 575 select X86_REBOOTFIXUPS 576 select OF 577 select OF_EARLY_FLATTREE 578 ---help--- 579 Select for the Intel CE media processor (CE4100) SOC. 580 This option compiles in support for the CE4100 SOC for settop 581 boxes and media devices. 582 583config X86_INTEL_MID 584 bool "Intel MID platform support" 585 depends on X86_EXTENDED_PLATFORM 586 depends on X86_PLATFORM_DEVICES 587 depends on PCI 588 depends on X86_64 || (PCI_GOANY && X86_32) 589 depends on X86_IO_APIC 590 select SFI 591 select I2C 592 select DW_APB_TIMER 593 select APB_TIMER 594 select INTEL_SCU_IPC 595 select MFD_INTEL_MSIC 596 ---help--- 597 Select to build a kernel capable of supporting Intel MID (Mobile 598 Internet Device) platform systems which do not have the PCI legacy 599 interfaces. If you are building for a PC class system say N here. 600 601 Intel MID platforms are based on an Intel processor and chipset which 602 consume less power than most of the x86 derivatives. 603 604config X86_INTEL_QUARK 605 bool "Intel Quark platform support" 606 depends on X86_32 607 depends on X86_EXTENDED_PLATFORM 608 depends on X86_PLATFORM_DEVICES 609 depends on X86_TSC 610 depends on PCI 611 depends on PCI_GOANY 612 depends on X86_IO_APIC 613 select IOSF_MBI 614 select INTEL_IMR 615 select COMMON_CLK 616 ---help--- 617 Select to include support for Quark X1000 SoC. 618 Say Y here if you have a Quark based system such as the Arduino 619 compatible Intel Galileo. 620 621config X86_INTEL_LPSS 622 bool "Intel Low Power Subsystem Support" 623 depends on X86 && ACPI && PCI 624 select COMMON_CLK 625 select PINCTRL 626 select IOSF_MBI 627 ---help--- 628 Select to build support for Intel Low Power Subsystem such as 629 found on Intel Lynxpoint PCH. Selecting this option enables 630 things like clock tree (common clock framework) and pincontrol 631 which are needed by the LPSS peripheral drivers. 632 633config X86_AMD_PLATFORM_DEVICE 634 bool "AMD ACPI2Platform devices support" 635 depends on ACPI 636 select COMMON_CLK 637 select PINCTRL 638 ---help--- 639 Select to interpret AMD specific ACPI device to platform device 640 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 641 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 642 implemented under PINCTRL subsystem. 643 644config IOSF_MBI 645 tristate "Intel SoC IOSF Sideband support for SoC platforms" 646 depends on PCI 647 ---help--- 648 This option enables sideband register access support for Intel SoC 649 platforms. On these platforms the IOSF sideband is used in lieu of 650 MSR's for some register accesses, mostly but not limited to thermal 651 and power. Drivers may query the availability of this device to 652 determine if they need the sideband in order to work on these 653 platforms. The sideband is available on the following SoC products. 654 This list is not meant to be exclusive. 655 - BayTrail 656 - Braswell 657 - Quark 658 659 You should say Y if you are running a kernel on one of these SoC's. 660 661config IOSF_MBI_DEBUG 662 bool "Enable IOSF sideband access through debugfs" 663 depends on IOSF_MBI && DEBUG_FS 664 ---help--- 665 Select this option to expose the IOSF sideband access registers (MCR, 666 MDR, MCRX) through debugfs to write and read register information from 667 different units on the SoC. This is most useful for obtaining device 668 state information for debug and analysis. As this is a general access 669 mechanism, users of this option would have specific knowledge of the 670 device they want to access. 671 672 If you don't require the option or are in doubt, say N. 673 674config X86_RDC321X 675 bool "RDC R-321x SoC" 676 depends on X86_32 677 depends on X86_EXTENDED_PLATFORM 678 select M486 679 select X86_REBOOTFIXUPS 680 ---help--- 681 This option is needed for RDC R-321x system-on-chip, also known 682 as R-8610-(G). 683 If you don't have one of these chips, you should say N here. 684 685config X86_32_NON_STANDARD 686 bool "Support non-standard 32-bit SMP architectures" 687 depends on X86_32 && SMP 688 depends on X86_EXTENDED_PLATFORM 689 ---help--- 690 This option compiles in the bigsmp and STA2X11 default 691 subarchitectures. It is intended for a generic binary 692 kernel. If you select them all, kernel will probe it one by 693 one and will fallback to default. 694 695# Alphabetically sorted list of Non standard 32 bit platforms 696 697config X86_SUPPORTS_MEMORY_FAILURE 698 def_bool y 699 # MCE code calls memory_failure(): 700 depends on X86_MCE 701 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 702 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 703 depends on X86_64 || !SPARSEMEM 704 select ARCH_SUPPORTS_MEMORY_FAILURE 705 706config STA2X11 707 bool "STA2X11 Companion Chip Support" 708 depends on X86_32_NON_STANDARD && PCI 709 select ARCH_HAS_PHYS_TO_DMA 710 select SWIOTLB 711 select MFD_STA2X11 712 select GPIOLIB 713 ---help--- 714 This adds support for boards based on the STA2X11 IO-Hub, 715 a.k.a. "ConneXt". The chip is used in place of the standard 716 PC chipset, so all "standard" peripherals are missing. If this 717 option is selected the kernel will still be able to boot on 718 standard PC machines. 719 720config X86_32_IRIS 721 tristate "Eurobraille/Iris poweroff module" 722 depends on X86_32 723 ---help--- 724 The Iris machines from EuroBraille do not have APM or ACPI support 725 to shut themselves down properly. A special I/O sequence is 726 needed to do so, which is what this module does at 727 kernel shutdown. 728 729 This is only for Iris machines from EuroBraille. 730 731 If unused, say N. 732 733config SCHED_OMIT_FRAME_POINTER 734 def_bool y 735 prompt "Single-depth WCHAN output" 736 depends on X86 737 ---help--- 738 Calculate simpler /proc/<PID>/wchan values. If this option 739 is disabled then wchan values will recurse back to the 740 caller function. This provides more accurate wchan values, 741 at the expense of slightly more scheduling overhead. 742 743 If in doubt, say "Y". 744 745menuconfig HYPERVISOR_GUEST 746 bool "Linux guest support" 747 ---help--- 748 Say Y here to enable options for running Linux under various hyper- 749 visors. This option enables basic hypervisor detection and platform 750 setup. 751 752 If you say N, all options in this submenu will be skipped and 753 disabled, and Linux guest support won't be built in. 754 755if HYPERVISOR_GUEST 756 757config PARAVIRT 758 bool "Enable paravirtualization code" 759 ---help--- 760 This changes the kernel so it can modify itself when it is run 761 under a hypervisor, potentially improving performance significantly 762 over full virtualization. However, when run without a hypervisor 763 the kernel is theoretically slower and slightly larger. 764 765config PARAVIRT_XXL 766 bool 767 768config PARAVIRT_DEBUG 769 bool "paravirt-ops debugging" 770 depends on PARAVIRT && DEBUG_KERNEL 771 ---help--- 772 Enable to debug paravirt_ops internals. Specifically, BUG if 773 a paravirt_op is missing when it is called. 774 775config PARAVIRT_SPINLOCKS 776 bool "Paravirtualization layer for spinlocks" 777 depends on PARAVIRT && SMP 778 ---help--- 779 Paravirtualized spinlocks allow a pvops backend to replace the 780 spinlock implementation with something virtualization-friendly 781 (for example, block the virtual CPU rather than spinning). 782 783 It has a minimal impact on native kernels and gives a nice performance 784 benefit on paravirtualized KVM / Xen kernels. 785 786 If you are unsure how to answer this question, answer Y. 787 788config X86_HV_CALLBACK_VECTOR 789 def_bool n 790 791source "arch/x86/xen/Kconfig" 792 793config KVM_GUEST 794 bool "KVM Guest support (including kvmclock)" 795 depends on PARAVIRT 796 select PARAVIRT_CLOCK 797 default y 798 ---help--- 799 This option enables various optimizations for running under the KVM 800 hypervisor. It includes a paravirtualized clock, so that instead 801 of relying on a PIT (or probably other) emulation by the 802 underlying device model, the host provides the guest with 803 timing infrastructure such as time of day, and system time 804 805config PVH 806 bool "Support for running PVH guests" 807 ---help--- 808 This option enables the PVH entry point for guest virtual machines 809 as specified in the x86/HVM direct boot ABI. 810 811config KVM_DEBUG_FS 812 bool "Enable debug information for KVM Guests in debugfs" 813 depends on KVM_GUEST && DEBUG_FS 814 ---help--- 815 This option enables collection of various statistics for KVM guest. 816 Statistics are displayed in debugfs filesystem. Enabling this option 817 may incur significant overhead. 818 819config PARAVIRT_TIME_ACCOUNTING 820 bool "Paravirtual steal time accounting" 821 depends on PARAVIRT 822 ---help--- 823 Select this option to enable fine granularity task steal time 824 accounting. Time spent executing other tasks in parallel with 825 the current vCPU is discounted from the vCPU power. To account for 826 that, there can be a small performance impact. 827 828 If in doubt, say N here. 829 830config PARAVIRT_CLOCK 831 bool 832 833config JAILHOUSE_GUEST 834 bool "Jailhouse non-root cell support" 835 depends on X86_64 && PCI 836 select X86_PM_TIMER 837 ---help--- 838 This option allows to run Linux as guest in a Jailhouse non-root 839 cell. You can leave this option disabled if you only want to start 840 Jailhouse and run Linux afterwards in the root cell. 841 842config ACRN_GUEST 843 bool "ACRN Guest support" 844 depends on X86_64 845 select X86_HV_CALLBACK_VECTOR 846 help 847 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 848 a flexible, lightweight reference open-source hypervisor, built with 849 real-time and safety-criticality in mind. It is built for embedded 850 IOT with small footprint and real-time features. More details can be 851 found in https://projectacrn.org/. 852 853endif #HYPERVISOR_GUEST 854 855source "arch/x86/Kconfig.cpu" 856 857config HPET_TIMER 858 def_bool X86_64 859 prompt "HPET Timer Support" if X86_32 860 ---help--- 861 Use the IA-PC HPET (High Precision Event Timer) to manage 862 time in preference to the PIT and RTC, if a HPET is 863 present. 864 HPET is the next generation timer replacing legacy 8254s. 865 The HPET provides a stable time base on SMP 866 systems, unlike the TSC, but it is more expensive to access, 867 as it is off-chip. The interface used is documented 868 in the HPET spec, revision 1. 869 870 You can safely choose Y here. However, HPET will only be 871 activated if the platform and the BIOS support this feature. 872 Otherwise the 8254 will be used for timing services. 873 874 Choose N to continue using the legacy 8254 timer. 875 876config HPET_EMULATE_RTC 877 def_bool y 878 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 879 880config APB_TIMER 881 def_bool y if X86_INTEL_MID 882 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 883 select DW_APB_TIMER 884 depends on X86_INTEL_MID && SFI 885 help 886 APB timer is the replacement for 8254, HPET on X86 MID platforms. 887 The APBT provides a stable time base on SMP 888 systems, unlike the TSC, but it is more expensive to access, 889 as it is off-chip. APB timers are always running regardless of CPU 890 C states, they are used as per CPU clockevent device when possible. 891 892# Mark as expert because too many people got it wrong. 893# The code disables itself when not needed. 894config DMI 895 default y 896 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 897 bool "Enable DMI scanning" if EXPERT 898 ---help--- 899 Enabled scanning of DMI to identify machine quirks. Say Y 900 here unless you have verified that your setup is not 901 affected by entries in the DMI blacklist. Required by PNP 902 BIOS code. 903 904config GART_IOMMU 905 bool "Old AMD GART IOMMU support" 906 select IOMMU_HELPER 907 select SWIOTLB 908 depends on X86_64 && PCI && AMD_NB 909 ---help--- 910 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 911 GART based hardware IOMMUs. 912 913 The GART supports full DMA access for devices with 32-bit access 914 limitations, on systems with more than 3 GB. This is usually needed 915 for USB, sound, many IDE/SATA chipsets and some other devices. 916 917 Newer systems typically have a modern AMD IOMMU, supported via 918 the CONFIG_AMD_IOMMU=y config option. 919 920 In normal configurations this driver is only active when needed: 921 there's more than 3 GB of memory and the system contains a 922 32-bit limited device. 923 924 If unsure, say Y. 925 926config CALGARY_IOMMU 927 bool "IBM Calgary IOMMU support" 928 select IOMMU_HELPER 929 select SWIOTLB 930 depends on X86_64 && PCI 931 ---help--- 932 Support for hardware IOMMUs in IBM's xSeries x366 and x460 933 systems. Needed to run systems with more than 3GB of memory 934 properly with 32-bit PCI devices that do not support DAC 935 (Double Address Cycle). Calgary also supports bus level 936 isolation, where all DMAs pass through the IOMMU. This 937 prevents them from going anywhere except their intended 938 destination. This catches hard-to-find kernel bugs and 939 mis-behaving drivers and devices that do not use the DMA-API 940 properly to set up their DMA buffers. The IOMMU can be 941 turned off at boot time with the iommu=off parameter. 942 Normally the kernel will make the right choice by itself. 943 If unsure, say Y. 944 945config CALGARY_IOMMU_ENABLED_BY_DEFAULT 946 def_bool y 947 prompt "Should Calgary be enabled by default?" 948 depends on CALGARY_IOMMU 949 ---help--- 950 Should Calgary be enabled by default? if you choose 'y', Calgary 951 will be used (if it exists). If you choose 'n', Calgary will not be 952 used even if it exists. If you choose 'n' and would like to use 953 Calgary anyway, pass 'iommu=calgary' on the kernel command line. 954 If unsure, say Y. 955 956config MAXSMP 957 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 958 depends on X86_64 && SMP && DEBUG_KERNEL 959 select CPUMASK_OFFSTACK 960 ---help--- 961 Enable maximum number of CPUS and NUMA Nodes for this architecture. 962 If unsure, say N. 963 964# 965# The maximum number of CPUs supported: 966# 967# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 968# and which can be configured interactively in the 969# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 970# 971# The ranges are different on 32-bit and 64-bit kernels, depending on 972# hardware capabilities and scalability features of the kernel. 973# 974# ( If MAXSMP is enabled we just use the highest possible value and disable 975# interactive configuration. ) 976# 977 978config NR_CPUS_RANGE_BEGIN 979 int 980 default NR_CPUS_RANGE_END if MAXSMP 981 default 1 if !SMP 982 default 2 983 984config NR_CPUS_RANGE_END 985 int 986 depends on X86_32 987 default 64 if SMP && X86_BIGSMP 988 default 8 if SMP && !X86_BIGSMP 989 default 1 if !SMP 990 991config NR_CPUS_RANGE_END 992 int 993 depends on X86_64 994 default 8192 if SMP && ( MAXSMP || CPUMASK_OFFSTACK) 995 default 512 if SMP && (!MAXSMP && !CPUMASK_OFFSTACK) 996 default 1 if !SMP 997 998config NR_CPUS_DEFAULT 999 int 1000 depends on X86_32 1001 default 32 if X86_BIGSMP 1002 default 8 if SMP 1003 default 1 if !SMP 1004 1005config NR_CPUS_DEFAULT 1006 int 1007 depends on X86_64 1008 default 8192 if MAXSMP 1009 default 64 if SMP 1010 default 1 if !SMP 1011 1012config NR_CPUS 1013 int "Maximum number of CPUs" if SMP && !MAXSMP 1014 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1015 default NR_CPUS_DEFAULT 1016 ---help--- 1017 This allows you to specify the maximum number of CPUs which this 1018 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1019 supported value is 8192, otherwise the maximum value is 512. The 1020 minimum value which makes sense is 2. 1021 1022 This is purely to save memory: each supported CPU adds about 8KB 1023 to the kernel image. 1024 1025config SCHED_SMT 1026 def_bool y if SMP 1027 1028config SCHED_MC 1029 def_bool y 1030 prompt "Multi-core scheduler support" 1031 depends on SMP 1032 ---help--- 1033 Multi-core scheduler support improves the CPU scheduler's decision 1034 making when dealing with multi-core CPU chips at a cost of slightly 1035 increased overhead in some places. If unsure say N here. 1036 1037config SCHED_MC_PRIO 1038 bool "CPU core priorities scheduler support" 1039 depends on SCHED_MC && CPU_SUP_INTEL 1040 select X86_INTEL_PSTATE 1041 select CPU_FREQ 1042 default y 1043 ---help--- 1044 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1045 core ordering determined at manufacturing time, which allows 1046 certain cores to reach higher turbo frequencies (when running 1047 single threaded workloads) than others. 1048 1049 Enabling this kernel feature teaches the scheduler about 1050 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1051 scheduler's CPU selection logic accordingly, so that higher 1052 overall system performance can be achieved. 1053 1054 This feature will have no effect on CPUs without this feature. 1055 1056 If unsure say Y here. 1057 1058config UP_LATE_INIT 1059 def_bool y 1060 depends on !SMP && X86_LOCAL_APIC 1061 1062config X86_UP_APIC 1063 bool "Local APIC support on uniprocessors" if !PCI_MSI 1064 default PCI_MSI 1065 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1066 ---help--- 1067 A local APIC (Advanced Programmable Interrupt Controller) is an 1068 integrated interrupt controller in the CPU. If you have a single-CPU 1069 system which has a processor with a local APIC, you can say Y here to 1070 enable and use it. If you say Y here even though your machine doesn't 1071 have a local APIC, then the kernel will still run with no slowdown at 1072 all. The local APIC supports CPU-generated self-interrupts (timer, 1073 performance counters), and the NMI watchdog which detects hard 1074 lockups. 1075 1076config X86_UP_IOAPIC 1077 bool "IO-APIC support on uniprocessors" 1078 depends on X86_UP_APIC 1079 ---help--- 1080 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1081 SMP-capable replacement for PC-style interrupt controllers. Most 1082 SMP systems and many recent uniprocessor systems have one. 1083 1084 If you have a single-CPU system with an IO-APIC, you can say Y here 1085 to use it. If you say Y here even though your machine doesn't have 1086 an IO-APIC, then the kernel will still run with no slowdown at all. 1087 1088config X86_LOCAL_APIC 1089 def_bool y 1090 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1091 select IRQ_DOMAIN_HIERARCHY 1092 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1093 1094config X86_IO_APIC 1095 def_bool y 1096 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1097 1098config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1099 bool "Reroute for broken boot IRQs" 1100 depends on X86_IO_APIC 1101 ---help--- 1102 This option enables a workaround that fixes a source of 1103 spurious interrupts. This is recommended when threaded 1104 interrupt handling is used on systems where the generation of 1105 superfluous "boot interrupts" cannot be disabled. 1106 1107 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1108 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1109 kernel does during interrupt handling). On chipsets where this 1110 boot IRQ generation cannot be disabled, this workaround keeps 1111 the original IRQ line masked so that only the equivalent "boot 1112 IRQ" is delivered to the CPUs. The workaround also tells the 1113 kernel to set up the IRQ handler on the boot IRQ line. In this 1114 way only one interrupt is delivered to the kernel. Otherwise 1115 the spurious second interrupt may cause the kernel to bring 1116 down (vital) interrupt lines. 1117 1118 Only affects "broken" chipsets. Interrupt sharing may be 1119 increased on these systems. 1120 1121config X86_MCE 1122 bool "Machine Check / overheating reporting" 1123 select GENERIC_ALLOCATOR 1124 default y 1125 ---help--- 1126 Machine Check support allows the processor to notify the 1127 kernel if it detects a problem (e.g. overheating, data corruption). 1128 The action the kernel takes depends on the severity of the problem, 1129 ranging from warning messages to halting the machine. 1130 1131config X86_MCELOG_LEGACY 1132 bool "Support for deprecated /dev/mcelog character device" 1133 depends on X86_MCE 1134 ---help--- 1135 Enable support for /dev/mcelog which is needed by the old mcelog 1136 userspace logging daemon. Consider switching to the new generation 1137 rasdaemon solution. 1138 1139config X86_MCE_INTEL 1140 def_bool y 1141 prompt "Intel MCE features" 1142 depends on X86_MCE && X86_LOCAL_APIC 1143 ---help--- 1144 Additional support for intel specific MCE features such as 1145 the thermal monitor. 1146 1147config X86_MCE_AMD 1148 def_bool y 1149 prompt "AMD MCE features" 1150 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1151 ---help--- 1152 Additional support for AMD specific MCE features such as 1153 the DRAM Error Threshold. 1154 1155config X86_ANCIENT_MCE 1156 bool "Support for old Pentium 5 / WinChip machine checks" 1157 depends on X86_32 && X86_MCE 1158 ---help--- 1159 Include support for machine check handling on old Pentium 5 or WinChip 1160 systems. These typically need to be enabled explicitly on the command 1161 line. 1162 1163config X86_MCE_THRESHOLD 1164 depends on X86_MCE_AMD || X86_MCE_INTEL 1165 def_bool y 1166 1167config X86_MCE_INJECT 1168 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1169 tristate "Machine check injector support" 1170 ---help--- 1171 Provide support for injecting machine checks for testing purposes. 1172 If you don't know what a machine check is and you don't do kernel 1173 QA it is safe to say n. 1174 1175config X86_THERMAL_VECTOR 1176 def_bool y 1177 depends on X86_MCE_INTEL 1178 1179source "arch/x86/events/Kconfig" 1180 1181config X86_LEGACY_VM86 1182 bool "Legacy VM86 support" 1183 depends on X86_32 1184 ---help--- 1185 This option allows user programs to put the CPU into V8086 1186 mode, which is an 80286-era approximation of 16-bit real mode. 1187 1188 Some very old versions of X and/or vbetool require this option 1189 for user mode setting. Similarly, DOSEMU will use it if 1190 available to accelerate real mode DOS programs. However, any 1191 recent version of DOSEMU, X, or vbetool should be fully 1192 functional even without kernel VM86 support, as they will all 1193 fall back to software emulation. Nevertheless, if you are using 1194 a 16-bit DOS program where 16-bit performance matters, vm86 1195 mode might be faster than emulation and you might want to 1196 enable this option. 1197 1198 Note that any app that works on a 64-bit kernel is unlikely to 1199 need this option, as 64-bit kernels don't, and can't, support 1200 V8086 mode. This option is also unrelated to 16-bit protected 1201 mode and is not needed to run most 16-bit programs under Wine. 1202 1203 Enabling this option increases the complexity of the kernel 1204 and slows down exception handling a tiny bit. 1205 1206 If unsure, say N here. 1207 1208config VM86 1209 bool 1210 default X86_LEGACY_VM86 1211 1212config X86_16BIT 1213 bool "Enable support for 16-bit segments" if EXPERT 1214 default y 1215 depends on MODIFY_LDT_SYSCALL 1216 ---help--- 1217 This option is required by programs like Wine to run 16-bit 1218 protected mode legacy code on x86 processors. Disabling 1219 this option saves about 300 bytes on i386, or around 6K text 1220 plus 16K runtime memory on x86-64, 1221 1222config X86_ESPFIX32 1223 def_bool y 1224 depends on X86_16BIT && X86_32 1225 1226config X86_ESPFIX64 1227 def_bool y 1228 depends on X86_16BIT && X86_64 1229 1230config X86_VSYSCALL_EMULATION 1231 bool "Enable vsyscall emulation" if EXPERT 1232 default y 1233 depends on X86_64 1234 ---help--- 1235 This enables emulation of the legacy vsyscall page. Disabling 1236 it is roughly equivalent to booting with vsyscall=none, except 1237 that it will also disable the helpful warning if a program 1238 tries to use a vsyscall. With this option set to N, offending 1239 programs will just segfault, citing addresses of the form 1240 0xffffffffff600?00. 1241 1242 This option is required by many programs built before 2013, and 1243 care should be used even with newer programs if set to N. 1244 1245 Disabling this option saves about 7K of kernel size and 1246 possibly 4K of additional runtime pagetable memory. 1247 1248config TOSHIBA 1249 tristate "Toshiba Laptop support" 1250 depends on X86_32 1251 ---help--- 1252 This adds a driver to safely access the System Management Mode of 1253 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1254 not work on models with a Phoenix BIOS. The System Management Mode 1255 is used to set the BIOS and power saving options on Toshiba portables. 1256 1257 For information on utilities to make use of this driver see the 1258 Toshiba Linux utilities web site at: 1259 <http://www.buzzard.org.uk/toshiba/>. 1260 1261 Say Y if you intend to run this kernel on a Toshiba portable. 1262 Say N otherwise. 1263 1264config I8K 1265 tristate "Dell i8k legacy laptop support" 1266 select HWMON 1267 select SENSORS_DELL_SMM 1268 ---help--- 1269 This option enables legacy /proc/i8k userspace interface in hwmon 1270 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1271 temperature and allows controlling fan speeds of Dell laptops via 1272 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1273 it reports also power and hotkey status. For fan speed control is 1274 needed userspace package i8kutils. 1275 1276 Say Y if you intend to run this kernel on old Dell laptops or want to 1277 use userspace package i8kutils. 1278 Say N otherwise. 1279 1280config X86_REBOOTFIXUPS 1281 bool "Enable X86 board specific fixups for reboot" 1282 depends on X86_32 1283 ---help--- 1284 This enables chipset and/or board specific fixups to be done 1285 in order to get reboot to work correctly. This is only needed on 1286 some combinations of hardware and BIOS. The symptom, for which 1287 this config is intended, is when reboot ends with a stalled/hung 1288 system. 1289 1290 Currently, the only fixup is for the Geode machines using 1291 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1292 1293 Say Y if you want to enable the fixup. Currently, it's safe to 1294 enable this option even if you don't need it. 1295 Say N otherwise. 1296 1297config MICROCODE 1298 bool "CPU microcode loading support" 1299 default y 1300 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1301 select FW_LOADER 1302 ---help--- 1303 If you say Y here, you will be able to update the microcode on 1304 Intel and AMD processors. The Intel support is for the IA32 family, 1305 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1306 AMD support is for families 0x10 and later. You will obviously need 1307 the actual microcode binary data itself which is not shipped with 1308 the Linux kernel. 1309 1310 The preferred method to load microcode from a detached initrd is described 1311 in Documentation/x86/microcode.rst. For that you need to enable 1312 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1313 initrd for microcode blobs. 1314 1315 In addition, you can build the microcode into the kernel. For that you 1316 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1317 config option. 1318 1319config MICROCODE_INTEL 1320 bool "Intel microcode loading support" 1321 depends on MICROCODE 1322 default MICROCODE 1323 select FW_LOADER 1324 ---help--- 1325 This options enables microcode patch loading support for Intel 1326 processors. 1327 1328 For the current Intel microcode data package go to 1329 <https://downloadcenter.intel.com> and search for 1330 'Linux Processor Microcode Data File'. 1331 1332config MICROCODE_AMD 1333 bool "AMD microcode loading support" 1334 depends on MICROCODE 1335 select FW_LOADER 1336 ---help--- 1337 If you select this option, microcode patch loading support for AMD 1338 processors will be enabled. 1339 1340config MICROCODE_OLD_INTERFACE 1341 bool "Ancient loading interface (DEPRECATED)" 1342 default n 1343 depends on MICROCODE 1344 ---help--- 1345 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1346 which was used by userspace tools like iucode_tool and microcode.ctl. 1347 It is inadequate because it runs too late to be able to properly 1348 load microcode on a machine and it needs special tools. Instead, you 1349 should've switched to the early loading method with the initrd or 1350 builtin microcode by now: Documentation/x86/microcode.rst 1351 1352config X86_MSR 1353 tristate "/dev/cpu/*/msr - Model-specific register support" 1354 ---help--- 1355 This device gives privileged processes access to the x86 1356 Model-Specific Registers (MSRs). It is a character device with 1357 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1358 MSR accesses are directed to a specific CPU on multi-processor 1359 systems. 1360 1361config X86_CPUID 1362 tristate "/dev/cpu/*/cpuid - CPU information support" 1363 ---help--- 1364 This device gives processes access to the x86 CPUID instruction to 1365 be executed on a specific processor. It is a character device 1366 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1367 /dev/cpu/31/cpuid. 1368 1369choice 1370 prompt "High Memory Support" 1371 default HIGHMEM4G 1372 depends on X86_32 1373 1374config NOHIGHMEM 1375 bool "off" 1376 ---help--- 1377 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1378 However, the address space of 32-bit x86 processors is only 4 1379 Gigabytes large. That means that, if you have a large amount of 1380 physical memory, not all of it can be "permanently mapped" by the 1381 kernel. The physical memory that's not permanently mapped is called 1382 "high memory". 1383 1384 If you are compiling a kernel which will never run on a machine with 1385 more than 1 Gigabyte total physical RAM, answer "off" here (default 1386 choice and suitable for most users). This will result in a "3GB/1GB" 1387 split: 3GB are mapped so that each process sees a 3GB virtual memory 1388 space and the remaining part of the 4GB virtual memory space is used 1389 by the kernel to permanently map as much physical memory as 1390 possible. 1391 1392 If the machine has between 1 and 4 Gigabytes physical RAM, then 1393 answer "4GB" here. 1394 1395 If more than 4 Gigabytes is used then answer "64GB" here. This 1396 selection turns Intel PAE (Physical Address Extension) mode on. 1397 PAE implements 3-level paging on IA32 processors. PAE is fully 1398 supported by Linux, PAE mode is implemented on all recent Intel 1399 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1400 then the kernel will not boot on CPUs that don't support PAE! 1401 1402 The actual amount of total physical memory will either be 1403 auto detected or can be forced by using a kernel command line option 1404 such as "mem=256M". (Try "man bootparam" or see the documentation of 1405 your boot loader (lilo or loadlin) about how to pass options to the 1406 kernel at boot time.) 1407 1408 If unsure, say "off". 1409 1410config HIGHMEM4G 1411 bool "4GB" 1412 ---help--- 1413 Select this if you have a 32-bit processor and between 1 and 4 1414 gigabytes of physical RAM. 1415 1416config HIGHMEM64G 1417 bool "64GB" 1418 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1419 select X86_PAE 1420 ---help--- 1421 Select this if you have a 32-bit processor and more than 4 1422 gigabytes of physical RAM. 1423 1424endchoice 1425 1426choice 1427 prompt "Memory split" if EXPERT 1428 default VMSPLIT_3G 1429 depends on X86_32 1430 ---help--- 1431 Select the desired split between kernel and user memory. 1432 1433 If the address range available to the kernel is less than the 1434 physical memory installed, the remaining memory will be available 1435 as "high memory". Accessing high memory is a little more costly 1436 than low memory, as it needs to be mapped into the kernel first. 1437 Note that increasing the kernel address space limits the range 1438 available to user programs, making the address space there 1439 tighter. Selecting anything other than the default 3G/1G split 1440 will also likely make your kernel incompatible with binary-only 1441 kernel modules. 1442 1443 If you are not absolutely sure what you are doing, leave this 1444 option alone! 1445 1446 config VMSPLIT_3G 1447 bool "3G/1G user/kernel split" 1448 config VMSPLIT_3G_OPT 1449 depends on !X86_PAE 1450 bool "3G/1G user/kernel split (for full 1G low memory)" 1451 config VMSPLIT_2G 1452 bool "2G/2G user/kernel split" 1453 config VMSPLIT_2G_OPT 1454 depends on !X86_PAE 1455 bool "2G/2G user/kernel split (for full 2G low memory)" 1456 config VMSPLIT_1G 1457 bool "1G/3G user/kernel split" 1458endchoice 1459 1460config PAGE_OFFSET 1461 hex 1462 default 0xB0000000 if VMSPLIT_3G_OPT 1463 default 0x80000000 if VMSPLIT_2G 1464 default 0x78000000 if VMSPLIT_2G_OPT 1465 default 0x40000000 if VMSPLIT_1G 1466 default 0xC0000000 1467 depends on X86_32 1468 1469config HIGHMEM 1470 def_bool y 1471 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1472 1473config X86_PAE 1474 bool "PAE (Physical Address Extension) Support" 1475 depends on X86_32 && !HIGHMEM4G 1476 select PHYS_ADDR_T_64BIT 1477 select SWIOTLB 1478 ---help--- 1479 PAE is required for NX support, and furthermore enables 1480 larger swapspace support for non-overcommit purposes. It 1481 has the cost of more pagetable lookup overhead, and also 1482 consumes more pagetable space per process. 1483 1484config X86_5LEVEL 1485 bool "Enable 5-level page tables support" 1486 select DYNAMIC_MEMORY_LAYOUT 1487 select SPARSEMEM_VMEMMAP 1488 depends on X86_64 1489 ---help--- 1490 5-level paging enables access to larger address space: 1491 upto 128 PiB of virtual address space and 4 PiB of 1492 physical address space. 1493 1494 It will be supported by future Intel CPUs. 1495 1496 A kernel with the option enabled can be booted on machines that 1497 support 4- or 5-level paging. 1498 1499 See Documentation/x86/x86_64/5level-paging.rst for more 1500 information. 1501 1502 Say N if unsure. 1503 1504config X86_DIRECT_GBPAGES 1505 def_bool y 1506 depends on X86_64 && !DEBUG_PAGEALLOC 1507 ---help--- 1508 Certain kernel features effectively disable kernel 1509 linear 1 GB mappings (even if the CPU otherwise 1510 supports them), so don't confuse the user by printing 1511 that we have them enabled. 1512 1513config X86_CPA_STATISTICS 1514 bool "Enable statistic for Change Page Attribute" 1515 depends on DEBUG_FS 1516 ---help--- 1517 Expose statistics about the Change Page Attribute mechanims, which 1518 helps to determine the effectiveness of preserving large and huge 1519 page mappings when mapping protections are changed. 1520 1521config ARCH_HAS_MEM_ENCRYPT 1522 def_bool y 1523 1524config AMD_MEM_ENCRYPT 1525 bool "AMD Secure Memory Encryption (SME) support" 1526 depends on X86_64 && CPU_SUP_AMD 1527 select DYNAMIC_PHYSICAL_MASK 1528 select ARCH_USE_MEMREMAP_PROT 1529 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1530 ---help--- 1531 Say yes to enable support for the encryption of system memory. 1532 This requires an AMD processor that supports Secure Memory 1533 Encryption (SME). 1534 1535config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1536 bool "Activate AMD Secure Memory Encryption (SME) by default" 1537 default y 1538 depends on AMD_MEM_ENCRYPT 1539 ---help--- 1540 Say yes to have system memory encrypted by default if running on 1541 an AMD processor that supports Secure Memory Encryption (SME). 1542 1543 If set to Y, then the encryption of system memory can be 1544 deactivated with the mem_encrypt=off command line option. 1545 1546 If set to N, then the encryption of system memory can be 1547 activated with the mem_encrypt=on command line option. 1548 1549# Common NUMA Features 1550config NUMA 1551 bool "Numa Memory Allocation and Scheduler Support" 1552 depends on SMP 1553 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1554 default y if X86_BIGSMP 1555 ---help--- 1556 Enable NUMA (Non Uniform Memory Access) support. 1557 1558 The kernel will try to allocate memory used by a CPU on the 1559 local memory controller of the CPU and add some more 1560 NUMA awareness to the kernel. 1561 1562 For 64-bit this is recommended if the system is Intel Core i7 1563 (or later), AMD Opteron, or EM64T NUMA. 1564 1565 For 32-bit this is only needed if you boot a 32-bit 1566 kernel on a 64-bit NUMA platform. 1567 1568 Otherwise, you should say N. 1569 1570config AMD_NUMA 1571 def_bool y 1572 prompt "Old style AMD Opteron NUMA detection" 1573 depends on X86_64 && NUMA && PCI 1574 ---help--- 1575 Enable AMD NUMA node topology detection. You should say Y here if 1576 you have a multi processor AMD system. This uses an old method to 1577 read the NUMA configuration directly from the builtin Northbridge 1578 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1579 which also takes priority if both are compiled in. 1580 1581config X86_64_ACPI_NUMA 1582 def_bool y 1583 prompt "ACPI NUMA detection" 1584 depends on X86_64 && NUMA && ACPI && PCI 1585 select ACPI_NUMA 1586 ---help--- 1587 Enable ACPI SRAT based node topology detection. 1588 1589# Some NUMA nodes have memory ranges that span 1590# other nodes. Even though a pfn is valid and 1591# between a node's start and end pfns, it may not 1592# reside on that node. See memmap_init_zone() 1593# for details. 1594config NODES_SPAN_OTHER_NODES 1595 def_bool y 1596 depends on X86_64_ACPI_NUMA 1597 1598config NUMA_EMU 1599 bool "NUMA emulation" 1600 depends on NUMA 1601 ---help--- 1602 Enable NUMA emulation. A flat machine will be split 1603 into virtual nodes when booted with "numa=fake=N", where N is the 1604 number of nodes. This is only useful for debugging. 1605 1606config NODES_SHIFT 1607 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1608 range 1 10 1609 default "10" if MAXSMP 1610 default "6" if X86_64 1611 default "3" 1612 depends on NEED_MULTIPLE_NODES 1613 ---help--- 1614 Specify the maximum number of NUMA Nodes available on the target 1615 system. Increases memory reserved to accommodate various tables. 1616 1617config ARCH_HAVE_MEMORY_PRESENT 1618 def_bool y 1619 depends on X86_32 && DISCONTIGMEM 1620 1621config ARCH_FLATMEM_ENABLE 1622 def_bool y 1623 depends on X86_32 && !NUMA 1624 1625config ARCH_DISCONTIGMEM_ENABLE 1626 def_bool n 1627 depends on NUMA && X86_32 1628 depends on BROKEN 1629 1630config ARCH_SPARSEMEM_ENABLE 1631 def_bool y 1632 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1633 select SPARSEMEM_STATIC if X86_32 1634 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1635 1636config ARCH_SPARSEMEM_DEFAULT 1637 def_bool X86_64 || (NUMA && X86_32) 1638 1639config ARCH_SELECT_MEMORY_MODEL 1640 def_bool y 1641 depends on ARCH_SPARSEMEM_ENABLE 1642 1643config ARCH_MEMORY_PROBE 1644 bool "Enable sysfs memory/probe interface" 1645 depends on X86_64 && MEMORY_HOTPLUG 1646 help 1647 This option enables a sysfs memory/probe interface for testing. 1648 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1649 If you are unsure how to answer this question, answer N. 1650 1651config ARCH_PROC_KCORE_TEXT 1652 def_bool y 1653 depends on X86_64 && PROC_KCORE 1654 1655config ILLEGAL_POINTER_VALUE 1656 hex 1657 default 0 if X86_32 1658 default 0xdead000000000000 if X86_64 1659 1660config X86_PMEM_LEGACY_DEVICE 1661 bool 1662 1663config X86_PMEM_LEGACY 1664 tristate "Support non-standard NVDIMMs and ADR protected memory" 1665 depends on PHYS_ADDR_T_64BIT 1666 depends on BLK_DEV 1667 select X86_PMEM_LEGACY_DEVICE 1668 select LIBNVDIMM 1669 help 1670 Treat memory marked using the non-standard e820 type of 12 as used 1671 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1672 The kernel will offer these regions to the 'pmem' driver so 1673 they can be used for persistent storage. 1674 1675 Say Y if unsure. 1676 1677config HIGHPTE 1678 bool "Allocate 3rd-level pagetables from highmem" 1679 depends on HIGHMEM 1680 ---help--- 1681 The VM uses one page table entry for each page of physical memory. 1682 For systems with a lot of RAM, this can be wasteful of precious 1683 low memory. Setting this option will put user-space page table 1684 entries in high memory. 1685 1686config X86_CHECK_BIOS_CORRUPTION 1687 bool "Check for low memory corruption" 1688 ---help--- 1689 Periodically check for memory corruption in low memory, which 1690 is suspected to be caused by BIOS. Even when enabled in the 1691 configuration, it is disabled at runtime. Enable it by 1692 setting "memory_corruption_check=1" on the kernel command 1693 line. By default it scans the low 64k of memory every 60 1694 seconds; see the memory_corruption_check_size and 1695 memory_corruption_check_period parameters in 1696 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1697 1698 When enabled with the default parameters, this option has 1699 almost no overhead, as it reserves a relatively small amount 1700 of memory and scans it infrequently. It both detects corruption 1701 and prevents it from affecting the running system. 1702 1703 It is, however, intended as a diagnostic tool; if repeatable 1704 BIOS-originated corruption always affects the same memory, 1705 you can use memmap= to prevent the kernel from using that 1706 memory. 1707 1708config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1709 bool "Set the default setting of memory_corruption_check" 1710 depends on X86_CHECK_BIOS_CORRUPTION 1711 default y 1712 ---help--- 1713 Set whether the default state of memory_corruption_check is 1714 on or off. 1715 1716config X86_RESERVE_LOW 1717 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1718 default 64 1719 range 4 640 1720 ---help--- 1721 Specify the amount of low memory to reserve for the BIOS. 1722 1723 The first page contains BIOS data structures that the kernel 1724 must not use, so that page must always be reserved. 1725 1726 By default we reserve the first 64K of physical RAM, as a 1727 number of BIOSes are known to corrupt that memory range 1728 during events such as suspend/resume or monitor cable 1729 insertion, so it must not be used by the kernel. 1730 1731 You can set this to 4 if you are absolutely sure that you 1732 trust the BIOS to get all its memory reservations and usages 1733 right. If you know your BIOS have problems beyond the 1734 default 64K area, you can set this to 640 to avoid using the 1735 entire low memory range. 1736 1737 If you have doubts about the BIOS (e.g. suspend/resume does 1738 not work or there's kernel crashes after certain hardware 1739 hotplug events) then you might want to enable 1740 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1741 typical corruption patterns. 1742 1743 Leave this to the default value of 64 if you are unsure. 1744 1745config MATH_EMULATION 1746 bool 1747 depends on MODIFY_LDT_SYSCALL 1748 prompt "Math emulation" if X86_32 1749 ---help--- 1750 Linux can emulate a math coprocessor (used for floating point 1751 operations) if you don't have one. 486DX and Pentium processors have 1752 a math coprocessor built in, 486SX and 386 do not, unless you added 1753 a 487DX or 387, respectively. (The messages during boot time can 1754 give you some hints here ["man dmesg"].) Everyone needs either a 1755 coprocessor or this emulation. 1756 1757 If you don't have a math coprocessor, you need to say Y here; if you 1758 say Y here even though you have a coprocessor, the coprocessor will 1759 be used nevertheless. (This behavior can be changed with the kernel 1760 command line option "no387", which comes handy if your coprocessor 1761 is broken. Try "man bootparam" or see the documentation of your boot 1762 loader (lilo or loadlin) about how to pass options to the kernel at 1763 boot time.) This means that it is a good idea to say Y here if you 1764 intend to use this kernel on different machines. 1765 1766 More information about the internals of the Linux math coprocessor 1767 emulation can be found in <file:arch/x86/math-emu/README>. 1768 1769 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1770 kernel, it won't hurt. 1771 1772config MTRR 1773 def_bool y 1774 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1775 ---help--- 1776 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1777 the Memory Type Range Registers (MTRRs) may be used to control 1778 processor access to memory ranges. This is most useful if you have 1779 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1780 allows bus write transfers to be combined into a larger transfer 1781 before bursting over the PCI/AGP bus. This can increase performance 1782 of image write operations 2.5 times or more. Saying Y here creates a 1783 /proc/mtrr file which may be used to manipulate your processor's 1784 MTRRs. Typically the X server should use this. 1785 1786 This code has a reasonably generic interface so that similar 1787 control registers on other processors can be easily supported 1788 as well: 1789 1790 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1791 Registers (ARRs) which provide a similar functionality to MTRRs. For 1792 these, the ARRs are used to emulate the MTRRs. 1793 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1794 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1795 write-combining. All of these processors are supported by this code 1796 and it makes sense to say Y here if you have one of them. 1797 1798 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1799 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1800 can lead to all sorts of problems, so it's good to say Y here. 1801 1802 You can safely say Y even if your machine doesn't have MTRRs, you'll 1803 just add about 9 KB to your kernel. 1804 1805 See <file:Documentation/x86/mtrr.rst> for more information. 1806 1807config MTRR_SANITIZER 1808 def_bool y 1809 prompt "MTRR cleanup support" 1810 depends on MTRR 1811 ---help--- 1812 Convert MTRR layout from continuous to discrete, so X drivers can 1813 add writeback entries. 1814 1815 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1816 The largest mtrr entry size for a continuous block can be set with 1817 mtrr_chunk_size. 1818 1819 If unsure, say Y. 1820 1821config MTRR_SANITIZER_ENABLE_DEFAULT 1822 int "MTRR cleanup enable value (0-1)" 1823 range 0 1 1824 default "0" 1825 depends on MTRR_SANITIZER 1826 ---help--- 1827 Enable mtrr cleanup default value 1828 1829config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1830 int "MTRR cleanup spare reg num (0-7)" 1831 range 0 7 1832 default "1" 1833 depends on MTRR_SANITIZER 1834 ---help--- 1835 mtrr cleanup spare entries default, it can be changed via 1836 mtrr_spare_reg_nr=N on the kernel command line. 1837 1838config X86_PAT 1839 def_bool y 1840 prompt "x86 PAT support" if EXPERT 1841 depends on MTRR 1842 ---help--- 1843 Use PAT attributes to setup page level cache control. 1844 1845 PATs are the modern equivalents of MTRRs and are much more 1846 flexible than MTRRs. 1847 1848 Say N here if you see bootup problems (boot crash, boot hang, 1849 spontaneous reboots) or a non-working video driver. 1850 1851 If unsure, say Y. 1852 1853config ARCH_USES_PG_UNCACHED 1854 def_bool y 1855 depends on X86_PAT 1856 1857config ARCH_RANDOM 1858 def_bool y 1859 prompt "x86 architectural random number generator" if EXPERT 1860 ---help--- 1861 Enable the x86 architectural RDRAND instruction 1862 (Intel Bull Mountain technology) to generate random numbers. 1863 If supported, this is a high bandwidth, cryptographically 1864 secure hardware random number generator. 1865 1866config X86_SMAP 1867 def_bool y 1868 prompt "Supervisor Mode Access Prevention" if EXPERT 1869 ---help--- 1870 Supervisor Mode Access Prevention (SMAP) is a security 1871 feature in newer Intel processors. There is a small 1872 performance cost if this enabled and turned on; there is 1873 also a small increase in the kernel size if this is enabled. 1874 1875 If unsure, say Y. 1876 1877config X86_INTEL_UMIP 1878 def_bool y 1879 depends on CPU_SUP_INTEL 1880 prompt "Intel User Mode Instruction Prevention" if EXPERT 1881 ---help--- 1882 The User Mode Instruction Prevention (UMIP) is a security 1883 feature in newer Intel processors. If enabled, a general 1884 protection fault is issued if the SGDT, SLDT, SIDT, SMSW 1885 or STR instructions are executed in user mode. These instructions 1886 unnecessarily expose information about the hardware state. 1887 1888 The vast majority of applications do not use these instructions. 1889 For the very few that do, software emulation is provided in 1890 specific cases in protected and virtual-8086 modes. Emulated 1891 results are dummy. 1892 1893config X86_INTEL_MPX 1894 prompt "Intel MPX (Memory Protection Extensions)" 1895 def_bool n 1896 # Note: only available in 64-bit mode due to VMA flags shortage 1897 depends on CPU_SUP_INTEL && X86_64 1898 select ARCH_USES_HIGH_VMA_FLAGS 1899 ---help--- 1900 MPX provides hardware features that can be used in 1901 conjunction with compiler-instrumented code to check 1902 memory references. It is designed to detect buffer 1903 overflow or underflow bugs. 1904 1905 This option enables running applications which are 1906 instrumented or otherwise use MPX. It does not use MPX 1907 itself inside the kernel or to protect the kernel 1908 against bad memory references. 1909 1910 Enabling this option will make the kernel larger: 1911 ~8k of kernel text and 36 bytes of data on a 64-bit 1912 defconfig. It adds a long to the 'mm_struct' which 1913 will increase the kernel memory overhead of each 1914 process and adds some branches to paths used during 1915 exec() and munmap(). 1916 1917 For details, see Documentation/x86/intel_mpx.rst 1918 1919 If unsure, say N. 1920 1921config X86_INTEL_MEMORY_PROTECTION_KEYS 1922 prompt "Intel Memory Protection Keys" 1923 def_bool y 1924 # Note: only available in 64-bit mode 1925 depends on CPU_SUP_INTEL && X86_64 1926 select ARCH_USES_HIGH_VMA_FLAGS 1927 select ARCH_HAS_PKEYS 1928 ---help--- 1929 Memory Protection Keys provides a mechanism for enforcing 1930 page-based protections, but without requiring modification of the 1931 page tables when an application changes protection domains. 1932 1933 For details, see Documentation/core-api/protection-keys.rst 1934 1935 If unsure, say y. 1936 1937config EFI 1938 bool "EFI runtime service support" 1939 depends on ACPI 1940 select UCS2_STRING 1941 select EFI_RUNTIME_WRAPPERS 1942 ---help--- 1943 This enables the kernel to use EFI runtime services that are 1944 available (such as the EFI variable services). 1945 1946 This option is only useful on systems that have EFI firmware. 1947 In addition, you should use the latest ELILO loader available 1948 at <http://elilo.sourceforge.net> in order to take advantage 1949 of EFI runtime services. However, even with this option, the 1950 resultant kernel should continue to boot on existing non-EFI 1951 platforms. 1952 1953config EFI_STUB 1954 bool "EFI stub support" 1955 depends on EFI && !X86_USE_3DNOW 1956 select RELOCATABLE 1957 ---help--- 1958 This kernel feature allows a bzImage to be loaded directly 1959 by EFI firmware without the use of a bootloader. 1960 1961 See Documentation/admin-guide/efi-stub.rst for more information. 1962 1963config EFI_MIXED 1964 bool "EFI mixed-mode support" 1965 depends on EFI_STUB && X86_64 1966 ---help--- 1967 Enabling this feature allows a 64-bit kernel to be booted 1968 on a 32-bit firmware, provided that your CPU supports 64-bit 1969 mode. 1970 1971 Note that it is not possible to boot a mixed-mode enabled 1972 kernel via the EFI boot stub - a bootloader that supports 1973 the EFI handover protocol must be used. 1974 1975 If unsure, say N. 1976 1977config SECCOMP 1978 def_bool y 1979 prompt "Enable seccomp to safely compute untrusted bytecode" 1980 ---help--- 1981 This kernel feature is useful for number crunching applications 1982 that may need to compute untrusted bytecode during their 1983 execution. By using pipes or other transports made available to 1984 the process as file descriptors supporting the read/write 1985 syscalls, it's possible to isolate those applications in 1986 their own address space using seccomp. Once seccomp is 1987 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 1988 and the task is only allowed to execute a few safe syscalls 1989 defined by each seccomp mode. 1990 1991 If unsure, say Y. Only embedded should say N here. 1992 1993source "kernel/Kconfig.hz" 1994 1995config KEXEC 1996 bool "kexec system call" 1997 select KEXEC_CORE 1998 ---help--- 1999 kexec is a system call that implements the ability to shutdown your 2000 current kernel, and to start another kernel. It is like a reboot 2001 but it is independent of the system firmware. And like a reboot 2002 you can start any kernel with it, not just Linux. 2003 2004 The name comes from the similarity to the exec system call. 2005 2006 It is an ongoing process to be certain the hardware in a machine 2007 is properly shutdown, so do not be surprised if this code does not 2008 initially work for you. As of this writing the exact hardware 2009 interface is strongly in flux, so no good recommendation can be 2010 made. 2011 2012config KEXEC_FILE 2013 bool "kexec file based system call" 2014 select KEXEC_CORE 2015 select BUILD_BIN2C 2016 depends on X86_64 2017 depends on CRYPTO=y 2018 depends on CRYPTO_SHA256=y 2019 ---help--- 2020 This is new version of kexec system call. This system call is 2021 file based and takes file descriptors as system call argument 2022 for kernel and initramfs as opposed to list of segments as 2023 accepted by previous system call. 2024 2025config ARCH_HAS_KEXEC_PURGATORY 2026 def_bool KEXEC_FILE 2027 2028config KEXEC_VERIFY_SIG 2029 bool "Verify kernel signature during kexec_file_load() syscall" 2030 depends on KEXEC_FILE 2031 ---help--- 2032 This option makes kernel signature verification mandatory for 2033 the kexec_file_load() syscall. 2034 2035 In addition to that option, you need to enable signature 2036 verification for the corresponding kernel image type being 2037 loaded in order for this to work. 2038 2039config KEXEC_BZIMAGE_VERIFY_SIG 2040 bool "Enable bzImage signature verification support" 2041 depends on KEXEC_VERIFY_SIG 2042 depends on SIGNED_PE_FILE_VERIFICATION 2043 select SYSTEM_TRUSTED_KEYRING 2044 ---help--- 2045 Enable bzImage signature verification support. 2046 2047config CRASH_DUMP 2048 bool "kernel crash dumps" 2049 depends on X86_64 || (X86_32 && HIGHMEM) 2050 ---help--- 2051 Generate crash dump after being started by kexec. 2052 This should be normally only set in special crash dump kernels 2053 which are loaded in the main kernel with kexec-tools into 2054 a specially reserved region and then later executed after 2055 a crash by kdump/kexec. The crash dump kernel must be compiled 2056 to a memory address not used by the main kernel or BIOS using 2057 PHYSICAL_START, or it must be built as a relocatable image 2058 (CONFIG_RELOCATABLE=y). 2059 For more details see Documentation/admin-guide/kdump/kdump.rst 2060 2061config KEXEC_JUMP 2062 bool "kexec jump" 2063 depends on KEXEC && HIBERNATION 2064 ---help--- 2065 Jump between original kernel and kexeced kernel and invoke 2066 code in physical address mode via KEXEC 2067 2068config PHYSICAL_START 2069 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2070 default "0x1000000" 2071 ---help--- 2072 This gives the physical address where the kernel is loaded. 2073 2074 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2075 bzImage will decompress itself to above physical address and 2076 run from there. Otherwise, bzImage will run from the address where 2077 it has been loaded by the boot loader and will ignore above physical 2078 address. 2079 2080 In normal kdump cases one does not have to set/change this option 2081 as now bzImage can be compiled as a completely relocatable image 2082 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2083 address. This option is mainly useful for the folks who don't want 2084 to use a bzImage for capturing the crash dump and want to use a 2085 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2086 to be specifically compiled to run from a specific memory area 2087 (normally a reserved region) and this option comes handy. 2088 2089 So if you are using bzImage for capturing the crash dump, 2090 leave the value here unchanged to 0x1000000 and set 2091 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2092 for capturing the crash dump change this value to start of 2093 the reserved region. In other words, it can be set based on 2094 the "X" value as specified in the "crashkernel=YM@XM" 2095 command line boot parameter passed to the panic-ed 2096 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2097 for more details about crash dumps. 2098 2099 Usage of bzImage for capturing the crash dump is recommended as 2100 one does not have to build two kernels. Same kernel can be used 2101 as production kernel and capture kernel. Above option should have 2102 gone away after relocatable bzImage support is introduced. But it 2103 is present because there are users out there who continue to use 2104 vmlinux for dump capture. This option should go away down the 2105 line. 2106 2107 Don't change this unless you know what you are doing. 2108 2109config RELOCATABLE 2110 bool "Build a relocatable kernel" 2111 default y 2112 ---help--- 2113 This builds a kernel image that retains relocation information 2114 so it can be loaded someplace besides the default 1MB. 2115 The relocations tend to make the kernel binary about 10% larger, 2116 but are discarded at runtime. 2117 2118 One use is for the kexec on panic case where the recovery kernel 2119 must live at a different physical address than the primary 2120 kernel. 2121 2122 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2123 it has been loaded at and the compile time physical address 2124 (CONFIG_PHYSICAL_START) is used as the minimum location. 2125 2126config RANDOMIZE_BASE 2127 bool "Randomize the address of the kernel image (KASLR)" 2128 depends on RELOCATABLE 2129 default y 2130 ---help--- 2131 In support of Kernel Address Space Layout Randomization (KASLR), 2132 this randomizes the physical address at which the kernel image 2133 is decompressed and the virtual address where the kernel 2134 image is mapped, as a security feature that deters exploit 2135 attempts relying on knowledge of the location of kernel 2136 code internals. 2137 2138 On 64-bit, the kernel physical and virtual addresses are 2139 randomized separately. The physical address will be anywhere 2140 between 16MB and the top of physical memory (up to 64TB). The 2141 virtual address will be randomized from 16MB up to 1GB (9 bits 2142 of entropy). Note that this also reduces the memory space 2143 available to kernel modules from 1.5GB to 1GB. 2144 2145 On 32-bit, the kernel physical and virtual addresses are 2146 randomized together. They will be randomized from 16MB up to 2147 512MB (8 bits of entropy). 2148 2149 Entropy is generated using the RDRAND instruction if it is 2150 supported. If RDTSC is supported, its value is mixed into 2151 the entropy pool as well. If neither RDRAND nor RDTSC are 2152 supported, then entropy is read from the i8254 timer. The 2153 usable entropy is limited by the kernel being built using 2154 2GB addressing, and that PHYSICAL_ALIGN must be at a 2155 minimum of 2MB. As a result, only 10 bits of entropy are 2156 theoretically possible, but the implementations are further 2157 limited due to memory layouts. 2158 2159 If unsure, say Y. 2160 2161# Relocation on x86 needs some additional build support 2162config X86_NEED_RELOCS 2163 def_bool y 2164 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2165 2166config PHYSICAL_ALIGN 2167 hex "Alignment value to which kernel should be aligned" 2168 default "0x200000" 2169 range 0x2000 0x1000000 if X86_32 2170 range 0x200000 0x1000000 if X86_64 2171 ---help--- 2172 This value puts the alignment restrictions on physical address 2173 where kernel is loaded and run from. Kernel is compiled for an 2174 address which meets above alignment restriction. 2175 2176 If bootloader loads the kernel at a non-aligned address and 2177 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2178 address aligned to above value and run from there. 2179 2180 If bootloader loads the kernel at a non-aligned address and 2181 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2182 load address and decompress itself to the address it has been 2183 compiled for and run from there. The address for which kernel is 2184 compiled already meets above alignment restrictions. Hence the 2185 end result is that kernel runs from a physical address meeting 2186 above alignment restrictions. 2187 2188 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2189 this value must be a multiple of 0x200000. 2190 2191 Don't change this unless you know what you are doing. 2192 2193config DYNAMIC_MEMORY_LAYOUT 2194 bool 2195 ---help--- 2196 This option makes base addresses of vmalloc and vmemmap as well as 2197 __PAGE_OFFSET movable during boot. 2198 2199config RANDOMIZE_MEMORY 2200 bool "Randomize the kernel memory sections" 2201 depends on X86_64 2202 depends on RANDOMIZE_BASE 2203 select DYNAMIC_MEMORY_LAYOUT 2204 default RANDOMIZE_BASE 2205 ---help--- 2206 Randomizes the base virtual address of kernel memory sections 2207 (physical memory mapping, vmalloc & vmemmap). This security feature 2208 makes exploits relying on predictable memory locations less reliable. 2209 2210 The order of allocations remains unchanged. Entropy is generated in 2211 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2212 configuration have in average 30,000 different possible virtual 2213 addresses for each memory section. 2214 2215 If unsure, say Y. 2216 2217config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2218 hex "Physical memory mapping padding" if EXPERT 2219 depends on RANDOMIZE_MEMORY 2220 default "0xa" if MEMORY_HOTPLUG 2221 default "0x0" 2222 range 0x1 0x40 if MEMORY_HOTPLUG 2223 range 0x0 0x40 2224 ---help--- 2225 Define the padding in terabytes added to the existing physical 2226 memory size during kernel memory randomization. It is useful 2227 for memory hotplug support but reduces the entropy available for 2228 address randomization. 2229 2230 If unsure, leave at the default value. 2231 2232config HOTPLUG_CPU 2233 def_bool y 2234 depends on SMP 2235 2236config BOOTPARAM_HOTPLUG_CPU0 2237 bool "Set default setting of cpu0_hotpluggable" 2238 depends on HOTPLUG_CPU 2239 ---help--- 2240 Set whether default state of cpu0_hotpluggable is on or off. 2241 2242 Say Y here to enable CPU0 hotplug by default. If this switch 2243 is turned on, there is no need to give cpu0_hotplug kernel 2244 parameter and the CPU0 hotplug feature is enabled by default. 2245 2246 Please note: there are two known CPU0 dependencies if you want 2247 to enable the CPU0 hotplug feature either by this switch or by 2248 cpu0_hotplug kernel parameter. 2249 2250 First, resume from hibernate or suspend always starts from CPU0. 2251 So hibernate and suspend are prevented if CPU0 is offline. 2252 2253 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2254 offline if any interrupt can not migrate out of CPU0. There may 2255 be other CPU0 dependencies. 2256 2257 Please make sure the dependencies are under your control before 2258 you enable this feature. 2259 2260 Say N if you don't want to enable CPU0 hotplug feature by default. 2261 You still can enable the CPU0 hotplug feature at boot by kernel 2262 parameter cpu0_hotplug. 2263 2264config DEBUG_HOTPLUG_CPU0 2265 def_bool n 2266 prompt "Debug CPU0 hotplug" 2267 depends on HOTPLUG_CPU 2268 ---help--- 2269 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2270 soon as possible and boots up userspace with CPU0 offlined. User 2271 can online CPU0 back after boot time. 2272 2273 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2274 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2275 compilation or giving cpu0_hotplug kernel parameter at boot. 2276 2277 If unsure, say N. 2278 2279config COMPAT_VDSO 2280 def_bool n 2281 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2282 depends on COMPAT_32 2283 ---help--- 2284 Certain buggy versions of glibc will crash if they are 2285 presented with a 32-bit vDSO that is not mapped at the address 2286 indicated in its segment table. 2287 2288 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2289 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2290 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2291 the only released version with the bug, but OpenSUSE 9 2292 contains a buggy "glibc 2.3.2". 2293 2294 The symptom of the bug is that everything crashes on startup, saying: 2295 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2296 2297 Saying Y here changes the default value of the vdso32 boot 2298 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2299 This works around the glibc bug but hurts performance. 2300 2301 If unsure, say N: if you are compiling your own kernel, you 2302 are unlikely to be using a buggy version of glibc. 2303 2304choice 2305 prompt "vsyscall table for legacy applications" 2306 depends on X86_64 2307 default LEGACY_VSYSCALL_XONLY 2308 help 2309 Legacy user code that does not know how to find the vDSO expects 2310 to be able to issue three syscalls by calling fixed addresses in 2311 kernel space. Since this location is not randomized with ASLR, 2312 it can be used to assist security vulnerability exploitation. 2313 2314 This setting can be changed at boot time via the kernel command 2315 line parameter vsyscall=[emulate|xonly|none]. 2316 2317 On a system with recent enough glibc (2.14 or newer) and no 2318 static binaries, you can say None without a performance penalty 2319 to improve security. 2320 2321 If unsure, select "Emulate execution only". 2322 2323 config LEGACY_VSYSCALL_EMULATE 2324 bool "Full emulation" 2325 help 2326 The kernel traps and emulates calls into the fixed vsyscall 2327 address mapping. This makes the mapping non-executable, but 2328 it still contains readable known contents, which could be 2329 used in certain rare security vulnerability exploits. This 2330 configuration is recommended when using legacy userspace 2331 that still uses vsyscalls along with legacy binary 2332 instrumentation tools that require code to be readable. 2333 2334 An example of this type of legacy userspace is running 2335 Pin on an old binary that still uses vsyscalls. 2336 2337 config LEGACY_VSYSCALL_XONLY 2338 bool "Emulate execution only" 2339 help 2340 The kernel traps and emulates calls into the fixed vsyscall 2341 address mapping and does not allow reads. This 2342 configuration is recommended when userspace might use the 2343 legacy vsyscall area but support for legacy binary 2344 instrumentation of legacy code is not needed. It mitigates 2345 certain uses of the vsyscall area as an ASLR-bypassing 2346 buffer. 2347 2348 config LEGACY_VSYSCALL_NONE 2349 bool "None" 2350 help 2351 There will be no vsyscall mapping at all. This will 2352 eliminate any risk of ASLR bypass due to the vsyscall 2353 fixed address mapping. Attempts to use the vsyscalls 2354 will be reported to dmesg, so that either old or 2355 malicious userspace programs can be identified. 2356 2357endchoice 2358 2359config CMDLINE_BOOL 2360 bool "Built-in kernel command line" 2361 ---help--- 2362 Allow for specifying boot arguments to the kernel at 2363 build time. On some systems (e.g. embedded ones), it is 2364 necessary or convenient to provide some or all of the 2365 kernel boot arguments with the kernel itself (that is, 2366 to not rely on the boot loader to provide them.) 2367 2368 To compile command line arguments into the kernel, 2369 set this option to 'Y', then fill in the 2370 boot arguments in CONFIG_CMDLINE. 2371 2372 Systems with fully functional boot loaders (i.e. non-embedded) 2373 should leave this option set to 'N'. 2374 2375config CMDLINE 2376 string "Built-in kernel command string" 2377 depends on CMDLINE_BOOL 2378 default "" 2379 ---help--- 2380 Enter arguments here that should be compiled into the kernel 2381 image and used at boot time. If the boot loader provides a 2382 command line at boot time, it is appended to this string to 2383 form the full kernel command line, when the system boots. 2384 2385 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2386 change this behavior. 2387 2388 In most cases, the command line (whether built-in or provided 2389 by the boot loader) should specify the device for the root 2390 file system. 2391 2392config CMDLINE_OVERRIDE 2393 bool "Built-in command line overrides boot loader arguments" 2394 depends on CMDLINE_BOOL 2395 ---help--- 2396 Set this option to 'Y' to have the kernel ignore the boot loader 2397 command line, and use ONLY the built-in command line. 2398 2399 This is used to work around broken boot loaders. This should 2400 be set to 'N' under normal conditions. 2401 2402config MODIFY_LDT_SYSCALL 2403 bool "Enable the LDT (local descriptor table)" if EXPERT 2404 default y 2405 ---help--- 2406 Linux can allow user programs to install a per-process x86 2407 Local Descriptor Table (LDT) using the modify_ldt(2) system 2408 call. This is required to run 16-bit or segmented code such as 2409 DOSEMU or some Wine programs. It is also used by some very old 2410 threading libraries. 2411 2412 Enabling this feature adds a small amount of overhead to 2413 context switches and increases the low-level kernel attack 2414 surface. Disabling it removes the modify_ldt(2) system call. 2415 2416 Saying 'N' here may make sense for embedded or server kernels. 2417 2418source "kernel/livepatch/Kconfig" 2419 2420endmenu 2421 2422config ARCH_HAS_ADD_PAGES 2423 def_bool y 2424 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2425 2426config ARCH_ENABLE_MEMORY_HOTPLUG 2427 def_bool y 2428 depends on X86_64 || (X86_32 && HIGHMEM) 2429 2430config ARCH_ENABLE_MEMORY_HOTREMOVE 2431 def_bool y 2432 depends on MEMORY_HOTPLUG 2433 2434config USE_PERCPU_NUMA_NODE_ID 2435 def_bool y 2436 depends on NUMA 2437 2438config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2439 def_bool y 2440 depends on X86_64 || X86_PAE 2441 2442config ARCH_ENABLE_HUGEPAGE_MIGRATION 2443 def_bool y 2444 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2445 2446config ARCH_ENABLE_THP_MIGRATION 2447 def_bool y 2448 depends on X86_64 && TRANSPARENT_HUGEPAGE 2449 2450menu "Power management and ACPI options" 2451 2452config ARCH_HIBERNATION_HEADER 2453 def_bool y 2454 depends on HIBERNATION 2455 2456source "kernel/power/Kconfig" 2457 2458source "drivers/acpi/Kconfig" 2459 2460source "drivers/sfi/Kconfig" 2461 2462config X86_APM_BOOT 2463 def_bool y 2464 depends on APM 2465 2466menuconfig APM 2467 tristate "APM (Advanced Power Management) BIOS support" 2468 depends on X86_32 && PM_SLEEP 2469 ---help--- 2470 APM is a BIOS specification for saving power using several different 2471 techniques. This is mostly useful for battery powered laptops with 2472 APM compliant BIOSes. If you say Y here, the system time will be 2473 reset after a RESUME operation, the /proc/apm device will provide 2474 battery status information, and user-space programs will receive 2475 notification of APM "events" (e.g. battery status change). 2476 2477 If you select "Y" here, you can disable actual use of the APM 2478 BIOS by passing the "apm=off" option to the kernel at boot time. 2479 2480 Note that the APM support is almost completely disabled for 2481 machines with more than one CPU. 2482 2483 In order to use APM, you will need supporting software. For location 2484 and more information, read <file:Documentation/power/apm-acpi.rst> 2485 and the Battery Powered Linux mini-HOWTO, available from 2486 <http://www.tldp.org/docs.html#howto>. 2487 2488 This driver does not spin down disk drives (see the hdparm(8) 2489 manpage ("man 8 hdparm") for that), and it doesn't turn off 2490 VESA-compliant "green" monitors. 2491 2492 This driver does not support the TI 4000M TravelMate and the ACER 2493 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2494 desktop machines also don't have compliant BIOSes, and this driver 2495 may cause those machines to panic during the boot phase. 2496 2497 Generally, if you don't have a battery in your machine, there isn't 2498 much point in using this driver and you should say N. If you get 2499 random kernel OOPSes or reboots that don't seem to be related to 2500 anything, try disabling/enabling this option (or disabling/enabling 2501 APM in your BIOS). 2502 2503 Some other things you should try when experiencing seemingly random, 2504 "weird" problems: 2505 2506 1) make sure that you have enough swap space and that it is 2507 enabled. 2508 2) pass the "no-hlt" option to the kernel 2509 3) switch on floating point emulation in the kernel and pass 2510 the "no387" option to the kernel 2511 4) pass the "floppy=nodma" option to the kernel 2512 5) pass the "mem=4M" option to the kernel (thereby disabling 2513 all but the first 4 MB of RAM) 2514 6) make sure that the CPU is not over clocked. 2515 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2516 8) disable the cache from your BIOS settings 2517 9) install a fan for the video card or exchange video RAM 2518 10) install a better fan for the CPU 2519 11) exchange RAM chips 2520 12) exchange the motherboard. 2521 2522 To compile this driver as a module, choose M here: the 2523 module will be called apm. 2524 2525if APM 2526 2527config APM_IGNORE_USER_SUSPEND 2528 bool "Ignore USER SUSPEND" 2529 ---help--- 2530 This option will ignore USER SUSPEND requests. On machines with a 2531 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2532 series notebooks, it is necessary to say Y because of a BIOS bug. 2533 2534config APM_DO_ENABLE 2535 bool "Enable PM at boot time" 2536 ---help--- 2537 Enable APM features at boot time. From page 36 of the APM BIOS 2538 specification: "When disabled, the APM BIOS does not automatically 2539 power manage devices, enter the Standby State, enter the Suspend 2540 State, or take power saving steps in response to CPU Idle calls." 2541 This driver will make CPU Idle calls when Linux is idle (unless this 2542 feature is turned off -- see "Do CPU IDLE calls", below). This 2543 should always save battery power, but more complicated APM features 2544 will be dependent on your BIOS implementation. You may need to turn 2545 this option off if your computer hangs at boot time when using APM 2546 support, or if it beeps continuously instead of suspending. Turn 2547 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2548 T400CDT. This is off by default since most machines do fine without 2549 this feature. 2550 2551config APM_CPU_IDLE 2552 depends on CPU_IDLE 2553 bool "Make CPU Idle calls when idle" 2554 ---help--- 2555 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2556 On some machines, this can activate improved power savings, such as 2557 a slowed CPU clock rate, when the machine is idle. These idle calls 2558 are made after the idle loop has run for some length of time (e.g., 2559 333 mS). On some machines, this will cause a hang at boot time or 2560 whenever the CPU becomes idle. (On machines with more than one CPU, 2561 this option does nothing.) 2562 2563config APM_DISPLAY_BLANK 2564 bool "Enable console blanking using APM" 2565 ---help--- 2566 Enable console blanking using the APM. Some laptops can use this to 2567 turn off the LCD backlight when the screen blanker of the Linux 2568 virtual console blanks the screen. Note that this is only used by 2569 the virtual console screen blanker, and won't turn off the backlight 2570 when using the X Window system. This also doesn't have anything to 2571 do with your VESA-compliant power-saving monitor. Further, this 2572 option doesn't work for all laptops -- it might not turn off your 2573 backlight at all, or it might print a lot of errors to the console, 2574 especially if you are using gpm. 2575 2576config APM_ALLOW_INTS 2577 bool "Allow interrupts during APM BIOS calls" 2578 ---help--- 2579 Normally we disable external interrupts while we are making calls to 2580 the APM BIOS as a measure to lessen the effects of a badly behaving 2581 BIOS implementation. The BIOS should reenable interrupts if it 2582 needs to. Unfortunately, some BIOSes do not -- especially those in 2583 many of the newer IBM Thinkpads. If you experience hangs when you 2584 suspend, try setting this to Y. Otherwise, say N. 2585 2586endif # APM 2587 2588source "drivers/cpufreq/Kconfig" 2589 2590source "drivers/cpuidle/Kconfig" 2591 2592source "drivers/idle/Kconfig" 2593 2594endmenu 2595 2596 2597menu "Bus options (PCI etc.)" 2598 2599choice 2600 prompt "PCI access mode" 2601 depends on X86_32 && PCI 2602 default PCI_GOANY 2603 ---help--- 2604 On PCI systems, the BIOS can be used to detect the PCI devices and 2605 determine their configuration. However, some old PCI motherboards 2606 have BIOS bugs and may crash if this is done. Also, some embedded 2607 PCI-based systems don't have any BIOS at all. Linux can also try to 2608 detect the PCI hardware directly without using the BIOS. 2609 2610 With this option, you can specify how Linux should detect the 2611 PCI devices. If you choose "BIOS", the BIOS will be used, 2612 if you choose "Direct", the BIOS won't be used, and if you 2613 choose "MMConfig", then PCI Express MMCONFIG will be used. 2614 If you choose "Any", the kernel will try MMCONFIG, then the 2615 direct access method and falls back to the BIOS if that doesn't 2616 work. If unsure, go with the default, which is "Any". 2617 2618config PCI_GOBIOS 2619 bool "BIOS" 2620 2621config PCI_GOMMCONFIG 2622 bool "MMConfig" 2623 2624config PCI_GODIRECT 2625 bool "Direct" 2626 2627config PCI_GOOLPC 2628 bool "OLPC XO-1" 2629 depends on OLPC 2630 2631config PCI_GOANY 2632 bool "Any" 2633 2634endchoice 2635 2636config PCI_BIOS 2637 def_bool y 2638 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2639 2640# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2641config PCI_DIRECT 2642 def_bool y 2643 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2644 2645config PCI_MMCONFIG 2646 bool "Support mmconfig PCI config space access" if X86_64 2647 default y 2648 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2649 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2650 2651config PCI_OLPC 2652 def_bool y 2653 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2654 2655config PCI_XEN 2656 def_bool y 2657 depends on PCI && XEN 2658 select SWIOTLB_XEN 2659 2660config MMCONF_FAM10H 2661 def_bool y 2662 depends on X86_64 && PCI_MMCONFIG && ACPI 2663 2664config PCI_CNB20LE_QUIRK 2665 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2666 depends on PCI 2667 help 2668 Read the PCI windows out of the CNB20LE host bridge. This allows 2669 PCI hotplug to work on systems with the CNB20LE chipset which do 2670 not have ACPI. 2671 2672 There's no public spec for this chipset, and this functionality 2673 is known to be incomplete. 2674 2675 You should say N unless you know you need this. 2676 2677config ISA_BUS 2678 bool "ISA bus support on modern systems" if EXPERT 2679 help 2680 Expose ISA bus device drivers and options available for selection and 2681 configuration. Enable this option if your target machine has an ISA 2682 bus. ISA is an older system, displaced by PCI and newer bus 2683 architectures -- if your target machine is modern, it probably does 2684 not have an ISA bus. 2685 2686 If unsure, say N. 2687 2688# x86_64 have no ISA slots, but can have ISA-style DMA. 2689config ISA_DMA_API 2690 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2691 default y 2692 help 2693 Enables ISA-style DMA support for devices requiring such controllers. 2694 If unsure, say Y. 2695 2696if X86_32 2697 2698config ISA 2699 bool "ISA support" 2700 ---help--- 2701 Find out whether you have ISA slots on your motherboard. ISA is the 2702 name of a bus system, i.e. the way the CPU talks to the other stuff 2703 inside your box. Other bus systems are PCI, EISA, MicroChannel 2704 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2705 newer boards don't support it. If you have ISA, say Y, otherwise N. 2706 2707config SCx200 2708 tristate "NatSemi SCx200 support" 2709 ---help--- 2710 This provides basic support for National Semiconductor's 2711 (now AMD's) Geode processors. The driver probes for the 2712 PCI-IDs of several on-chip devices, so its a good dependency 2713 for other scx200_* drivers. 2714 2715 If compiled as a module, the driver is named scx200. 2716 2717config SCx200HR_TIMER 2718 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2719 depends on SCx200 2720 default y 2721 ---help--- 2722 This driver provides a clocksource built upon the on-chip 2723 27MHz high-resolution timer. Its also a workaround for 2724 NSC Geode SC-1100's buggy TSC, which loses time when the 2725 processor goes idle (as is done by the scheduler). The 2726 other workaround is idle=poll boot option. 2727 2728config OLPC 2729 bool "One Laptop Per Child support" 2730 depends on !X86_PAE 2731 select GPIOLIB 2732 select OF 2733 select OF_PROMTREE 2734 select IRQ_DOMAIN 2735 select OLPC_EC 2736 ---help--- 2737 Add support for detecting the unique features of the OLPC 2738 XO hardware. 2739 2740config OLPC_XO1_PM 2741 bool "OLPC XO-1 Power Management" 2742 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2743 ---help--- 2744 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2745 2746config OLPC_XO1_RTC 2747 bool "OLPC XO-1 Real Time Clock" 2748 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2749 ---help--- 2750 Add support for the XO-1 real time clock, which can be used as a 2751 programmable wakeup source. 2752 2753config OLPC_XO1_SCI 2754 bool "OLPC XO-1 SCI extras" 2755 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2756 depends on INPUT=y 2757 select POWER_SUPPLY 2758 ---help--- 2759 Add support for SCI-based features of the OLPC XO-1 laptop: 2760 - EC-driven system wakeups 2761 - Power button 2762 - Ebook switch 2763 - Lid switch 2764 - AC adapter status updates 2765 - Battery status updates 2766 2767config OLPC_XO15_SCI 2768 bool "OLPC XO-1.5 SCI extras" 2769 depends on OLPC && ACPI 2770 select POWER_SUPPLY 2771 ---help--- 2772 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2773 - EC-driven system wakeups 2774 - AC adapter status updates 2775 - Battery status updates 2776 2777config ALIX 2778 bool "PCEngines ALIX System Support (LED setup)" 2779 select GPIOLIB 2780 ---help--- 2781 This option enables system support for the PCEngines ALIX. 2782 At present this just sets up LEDs for GPIO control on 2783 ALIX2/3/6 boards. However, other system specific setup should 2784 get added here. 2785 2786 Note: You must still enable the drivers for GPIO and LED support 2787 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2788 2789 Note: You have to set alix.force=1 for boards with Award BIOS. 2790 2791config NET5501 2792 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2793 select GPIOLIB 2794 ---help--- 2795 This option enables system support for the Soekris Engineering net5501. 2796 2797config GEOS 2798 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2799 select GPIOLIB 2800 depends on DMI 2801 ---help--- 2802 This option enables system support for the Traverse Technologies GEOS. 2803 2804config TS5500 2805 bool "Technologic Systems TS-5500 platform support" 2806 depends on MELAN 2807 select CHECK_SIGNATURE 2808 select NEW_LEDS 2809 select LEDS_CLASS 2810 ---help--- 2811 This option enables system support for the Technologic Systems TS-5500. 2812 2813endif # X86_32 2814 2815config AMD_NB 2816 def_bool y 2817 depends on CPU_SUP_AMD && PCI 2818 2819config X86_SYSFB 2820 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2821 help 2822 Firmwares often provide initial graphics framebuffers so the BIOS, 2823 bootloader or kernel can show basic video-output during boot for 2824 user-guidance and debugging. Historically, x86 used the VESA BIOS 2825 Extensions and EFI-framebuffers for this, which are mostly limited 2826 to x86. 2827 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2828 framebuffers so the new generic system-framebuffer drivers can be 2829 used on x86. If the framebuffer is not compatible with the generic 2830 modes, it is advertised as fallback platform framebuffer so legacy 2831 drivers like efifb, vesafb and uvesafb can pick it up. 2832 If this option is not selected, all system framebuffers are always 2833 marked as fallback platform framebuffers as usual. 2834 2835 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2836 not be able to pick up generic system framebuffers if this option 2837 is selected. You are highly encouraged to enable simplefb as 2838 replacement if you select this option. simplefb can correctly deal 2839 with generic system framebuffers. But you should still keep vesafb 2840 and others enabled as fallback if a system framebuffer is 2841 incompatible with simplefb. 2842 2843 If unsure, say Y. 2844 2845endmenu 2846 2847 2848menu "Binary Emulations" 2849 2850config IA32_EMULATION 2851 bool "IA32 Emulation" 2852 depends on X86_64 2853 select ARCH_WANT_OLD_COMPAT_IPC 2854 select BINFMT_ELF 2855 select COMPAT_BINFMT_ELF 2856 select COMPAT_OLD_SIGACTION 2857 ---help--- 2858 Include code to run legacy 32-bit programs under a 2859 64-bit kernel. You should likely turn this on, unless you're 2860 100% sure that you don't have any 32-bit programs left. 2861 2862config IA32_AOUT 2863 tristate "IA32 a.out support" 2864 depends on IA32_EMULATION 2865 depends on BROKEN 2866 ---help--- 2867 Support old a.out binaries in the 32bit emulation. 2868 2869config X86_X32 2870 bool "x32 ABI for 64-bit mode" 2871 depends on X86_64 2872 ---help--- 2873 Include code to run binaries for the x32 native 32-bit ABI 2874 for 64-bit processors. An x32 process gets access to the 2875 full 64-bit register file and wide data path while leaving 2876 pointers at 32 bits for smaller memory footprint. 2877 2878 You will need a recent binutils (2.22 or later) with 2879 elf32_x86_64 support enabled to compile a kernel with this 2880 option set. 2881 2882config COMPAT_32 2883 def_bool y 2884 depends on IA32_EMULATION || X86_32 2885 select HAVE_UID16 2886 select OLD_SIGSUSPEND3 2887 2888config COMPAT 2889 def_bool y 2890 depends on IA32_EMULATION || X86_X32 2891 2892if COMPAT 2893config COMPAT_FOR_U64_ALIGNMENT 2894 def_bool y 2895 2896config SYSVIPC_COMPAT 2897 def_bool y 2898 depends on SYSVIPC 2899endif 2900 2901endmenu 2902 2903 2904config HAVE_ATOMIC_IOMAP 2905 def_bool y 2906 depends on X86_32 2907 2908config X86_DEV_DMA_OPS 2909 bool 2910 2911source "drivers/firmware/Kconfig" 2912 2913source "arch/x86/kvm/Kconfig" 2914