1# SPDX-License-Identifier: GPL-2.0 2# Select 32 or 64 bit 3config 64BIT 4 bool "64-bit kernel" if "$(ARCH)" = "x86" 5 default "$(ARCH)" != "i386" 6 ---help--- 7 Say yes to build a 64-bit kernel - formerly known as x86_64 8 Say no to build a 32-bit kernel - formerly known as i386 9 10config X86_32 11 def_bool y 12 depends on !64BIT 13 # Options that are inherently 32-bit kernel only: 14 select ARCH_WANT_IPC_PARSE_VERSION 15 select CLKSRC_I8253 16 select CLONE_BACKWARDS 17 select HAVE_DEBUG_STACKOVERFLOW 18 select MODULES_USE_ELF_REL 19 select OLD_SIGACTION 20 select GENERIC_VDSO_32 21 22config X86_64 23 def_bool y 24 depends on 64BIT 25 # Options that are inherently 64-bit kernel only: 26 select ARCH_HAS_GIGANTIC_PAGE 27 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 28 select ARCH_USE_CMPXCHG_LOCKREF 29 select HAVE_ARCH_SOFT_DIRTY 30 select MODULES_USE_ELF_RELA 31 select NEED_DMA_MAP_STATE 32 select SWIOTLB 33 34config FORCE_DYNAMIC_FTRACE 35 def_bool y 36 depends on X86_32 37 depends on FUNCTION_TRACER 38 select DYNAMIC_FTRACE 39 help 40 We keep the static function tracing (!DYNAMIC_FTRACE) around 41 in order to test the non static function tracing in the 42 generic code, as other architectures still use it. But we 43 only need to keep it around for x86_64. No need to keep it 44 for x86_32. For x86_32, force DYNAMIC_FTRACE. 45# 46# Arch settings 47# 48# ( Note that options that are marked 'if X86_64' could in principle be 49# ported to 32-bit as well. ) 50# 51config X86 52 def_bool y 53 # 54 # Note: keep this list sorted alphabetically 55 # 56 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 57 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 58 select ARCH_32BIT_OFF_T if X86_32 59 select ARCH_CLOCKSOURCE_INIT 60 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 61 select ARCH_HAS_DEBUG_VIRTUAL 62 select ARCH_HAS_DEVMEM_IS_ALLOWED 63 select ARCH_HAS_ELF_RANDOMIZE 64 select ARCH_HAS_FAST_MULTIPLIER 65 select ARCH_HAS_FILTER_PGPROT 66 select ARCH_HAS_FORTIFY_SOURCE 67 select ARCH_HAS_GCOV_PROFILE_ALL 68 select ARCH_HAS_KCOV if X86_64 69 select ARCH_HAS_MEM_ENCRYPT 70 select ARCH_HAS_MEMBARRIER_SYNC_CORE 71 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 72 select ARCH_HAS_PMEM_API if X86_64 73 select ARCH_HAS_PTE_DEVMAP if X86_64 74 select ARCH_HAS_PTE_SPECIAL 75 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 76 select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE 77 select ARCH_HAS_SET_MEMORY 78 select ARCH_HAS_SET_DIRECT_MAP 79 select ARCH_HAS_STRICT_KERNEL_RWX 80 select ARCH_HAS_STRICT_MODULE_RWX 81 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 82 select ARCH_HAS_SYSCALL_WRAPPER 83 select ARCH_HAS_UBSAN_SANITIZE_ALL 84 select ARCH_HAVE_NMI_SAFE_CMPXCHG 85 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 86 select ARCH_MIGHT_HAVE_PC_PARPORT 87 select ARCH_MIGHT_HAVE_PC_SERIO 88 select ARCH_STACKWALK 89 select ARCH_SUPPORTS_ACPI 90 select ARCH_SUPPORTS_ATOMIC_RMW 91 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 92 select ARCH_USE_BUILTIN_BSWAP 93 select ARCH_USE_QUEUED_RWLOCKS 94 select ARCH_USE_QUEUED_SPINLOCKS 95 select ARCH_USE_SYM_ANNOTATIONS 96 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 97 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 98 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 99 select ARCH_WANT_HUGE_PMD_SHARE 100 select ARCH_WANTS_THP_SWAP if X86_64 101 select BUILDTIME_TABLE_SORT 102 select CLKEVT_I8253 103 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 104 select CLOCKSOURCE_WATCHDOG 105 select DCACHE_WORD_ACCESS 106 select EDAC_ATOMIC_SCRUB 107 select EDAC_SUPPORT 108 select GENERIC_CLOCKEVENTS 109 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 110 select GENERIC_CLOCKEVENTS_MIN_ADJUST 111 select GENERIC_CMOS_UPDATE 112 select GENERIC_CPU_AUTOPROBE 113 select GENERIC_CPU_VULNERABILITIES 114 select GENERIC_EARLY_IOREMAP 115 select GENERIC_FIND_FIRST_BIT 116 select GENERIC_IOMAP 117 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 118 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 119 select GENERIC_IRQ_MIGRATION if SMP 120 select GENERIC_IRQ_PROBE 121 select GENERIC_IRQ_RESERVATION_MODE 122 select GENERIC_IRQ_SHOW 123 select GENERIC_PENDING_IRQ if SMP 124 select GENERIC_PTDUMP 125 select GENERIC_SMP_IDLE_THREAD 126 select GENERIC_STRNCPY_FROM_USER 127 select GENERIC_STRNLEN_USER 128 select GENERIC_TIME_VSYSCALL 129 select GENERIC_GETTIMEOFDAY 130 select GENERIC_VDSO_TIME_NS 131 select GUP_GET_PTE_LOW_HIGH if X86_PAE 132 select HARDIRQS_SW_RESEND 133 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 134 select HAVE_ACPI_APEI if ACPI 135 select HAVE_ACPI_APEI_NMI if ACPI 136 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 137 select HAVE_ARCH_AUDITSYSCALL 138 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 139 select HAVE_ARCH_JUMP_LABEL 140 select HAVE_ARCH_JUMP_LABEL_RELATIVE 141 select HAVE_ARCH_KASAN if X86_64 142 select HAVE_ARCH_KASAN_VMALLOC if X86_64 143 select HAVE_ARCH_KGDB 144 select HAVE_ARCH_MMAP_RND_BITS if MMU 145 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 146 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 147 select HAVE_ARCH_PREL32_RELOCATIONS 148 select HAVE_ARCH_SECCOMP_FILTER 149 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 150 select HAVE_ARCH_STACKLEAK 151 select HAVE_ARCH_TRACEHOOK 152 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 153 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 154 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 155 select HAVE_ARCH_VMAP_STACK if X86_64 156 select HAVE_ARCH_WITHIN_STACK_FRAMES 157 select HAVE_ASM_MODVERSIONS 158 select HAVE_CMPXCHG_DOUBLE 159 select HAVE_CMPXCHG_LOCAL 160 select HAVE_CONTEXT_TRACKING if X86_64 161 select HAVE_COPY_THREAD_TLS 162 select HAVE_C_RECORDMCOUNT 163 select HAVE_DEBUG_KMEMLEAK 164 select HAVE_DMA_CONTIGUOUS 165 select HAVE_DYNAMIC_FTRACE 166 select HAVE_DYNAMIC_FTRACE_WITH_REGS 167 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 168 select HAVE_EBPF_JIT 169 select HAVE_EFFICIENT_UNALIGNED_ACCESS 170 select HAVE_EISA 171 select HAVE_EXIT_THREAD 172 select HAVE_FAST_GUP 173 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 174 select HAVE_FTRACE_MCOUNT_RECORD 175 select HAVE_FUNCTION_GRAPH_TRACER 176 select HAVE_FUNCTION_TRACER 177 select HAVE_GCC_PLUGINS 178 select HAVE_HW_BREAKPOINT 179 select HAVE_IDE 180 select HAVE_IOREMAP_PROT 181 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 182 select HAVE_IRQ_TIME_ACCOUNTING 183 select HAVE_KERNEL_BZIP2 184 select HAVE_KERNEL_GZIP 185 select HAVE_KERNEL_LZ4 186 select HAVE_KERNEL_LZMA 187 select HAVE_KERNEL_LZO 188 select HAVE_KERNEL_XZ 189 select HAVE_KPROBES 190 select HAVE_KPROBES_ON_FTRACE 191 select HAVE_FUNCTION_ERROR_INJECTION 192 select HAVE_KRETPROBES 193 select HAVE_KVM 194 select HAVE_LIVEPATCH if X86_64 195 select HAVE_MEMBLOCK_NODE_MAP 196 select HAVE_MIXED_BREAKPOINTS_REGS 197 select HAVE_MOD_ARCH_SPECIFIC 198 select HAVE_MOVE_PMD 199 select HAVE_NMI 200 select HAVE_OPROFILE 201 select HAVE_OPTPROBES 202 select HAVE_PCSPKR_PLATFORM 203 select HAVE_PERF_EVENTS 204 select HAVE_PERF_EVENTS_NMI 205 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 206 select HAVE_PCI 207 select HAVE_PERF_REGS 208 select HAVE_PERF_USER_STACK_DUMP 209 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 210 select HAVE_REGS_AND_STACK_ACCESS_API 211 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 212 select HAVE_FUNCTION_ARG_ACCESS_API 213 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 214 select HAVE_STACK_VALIDATION if X86_64 215 select HAVE_RSEQ 216 select HAVE_SYSCALL_TRACEPOINTS 217 select HAVE_UNSTABLE_SCHED_CLOCK 218 select HAVE_USER_RETURN_NOTIFIER 219 select HAVE_GENERIC_VDSO 220 select HOTPLUG_SMT if SMP 221 select IRQ_FORCED_THREADING 222 select NEED_SG_DMA_LENGTH 223 select PCI_DOMAINS if PCI 224 select PCI_LOCKLESS_CONFIG if PCI 225 select PERF_EVENTS 226 select RTC_LIB 227 select RTC_MC146818_LIB 228 select SPARSE_IRQ 229 select SRCU 230 select SYSCTL_EXCEPTION_TRACE 231 select THREAD_INFO_IN_TASK 232 select USER_STACKTRACE_SUPPORT 233 select VIRT_TO_BUS 234 select X86_FEATURE_NAMES if PROC_FS 235 select PROC_PID_ARCH_STATUS if PROC_FS 236 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 237 238config INSTRUCTION_DECODER 239 def_bool y 240 depends on KPROBES || PERF_EVENTS || UPROBES 241 242config OUTPUT_FORMAT 243 string 244 default "elf32-i386" if X86_32 245 default "elf64-x86-64" if X86_64 246 247config LOCKDEP_SUPPORT 248 def_bool y 249 250config STACKTRACE_SUPPORT 251 def_bool y 252 253config MMU 254 def_bool y 255 256config ARCH_MMAP_RND_BITS_MIN 257 default 28 if 64BIT 258 default 8 259 260config ARCH_MMAP_RND_BITS_MAX 261 default 32 if 64BIT 262 default 16 263 264config ARCH_MMAP_RND_COMPAT_BITS_MIN 265 default 8 266 267config ARCH_MMAP_RND_COMPAT_BITS_MAX 268 default 16 269 270config SBUS 271 bool 272 273config GENERIC_ISA_DMA 274 def_bool y 275 depends on ISA_DMA_API 276 277config GENERIC_BUG 278 def_bool y 279 depends on BUG 280 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 281 282config GENERIC_BUG_RELATIVE_POINTERS 283 bool 284 285config ARCH_MAY_HAVE_PC_FDC 286 def_bool y 287 depends on ISA_DMA_API 288 289config GENERIC_CALIBRATE_DELAY 290 def_bool y 291 292config ARCH_HAS_CPU_RELAX 293 def_bool y 294 295config ARCH_HAS_CACHE_LINE_SIZE 296 def_bool y 297 298config ARCH_HAS_FILTER_PGPROT 299 def_bool y 300 301config HAVE_SETUP_PER_CPU_AREA 302 def_bool y 303 304config NEED_PER_CPU_EMBED_FIRST_CHUNK 305 def_bool y 306 307config NEED_PER_CPU_PAGE_FIRST_CHUNK 308 def_bool y 309 310config ARCH_HIBERNATION_POSSIBLE 311 def_bool y 312 313config ARCH_SUSPEND_POSSIBLE 314 def_bool y 315 316config ARCH_WANT_GENERAL_HUGETLB 317 def_bool y 318 319config ZONE_DMA32 320 def_bool y if X86_64 321 322config AUDIT_ARCH 323 def_bool y if X86_64 324 325config ARCH_SUPPORTS_DEBUG_PAGEALLOC 326 def_bool y 327 328config KASAN_SHADOW_OFFSET 329 hex 330 depends on KASAN 331 default 0xdffffc0000000000 332 333config HAVE_INTEL_TXT 334 def_bool y 335 depends on INTEL_IOMMU && ACPI 336 337config X86_32_SMP 338 def_bool y 339 depends on X86_32 && SMP 340 341config X86_64_SMP 342 def_bool y 343 depends on X86_64 && SMP 344 345config X86_32_LAZY_GS 346 def_bool y 347 depends on X86_32 && !STACKPROTECTOR 348 349config ARCH_SUPPORTS_UPROBES 350 def_bool y 351 352config FIX_EARLYCON_MEM 353 def_bool y 354 355config DYNAMIC_PHYSICAL_MASK 356 bool 357 358config PGTABLE_LEVELS 359 int 360 default 5 if X86_5LEVEL 361 default 4 if X86_64 362 default 3 if X86_PAE 363 default 2 364 365config CC_HAS_SANE_STACKPROTECTOR 366 bool 367 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 368 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 369 help 370 We have to make sure stack protector is unconditionally disabled if 371 the compiler produces broken code. 372 373menu "Processor type and features" 374 375config ZONE_DMA 376 bool "DMA memory allocation support" if EXPERT 377 default y 378 help 379 DMA memory allocation support allows devices with less than 32-bit 380 addressing to allocate within the first 16MB of address space. 381 Disable if no such devices will be used. 382 383 If unsure, say Y. 384 385config SMP 386 bool "Symmetric multi-processing support" 387 ---help--- 388 This enables support for systems with more than one CPU. If you have 389 a system with only one CPU, say N. If you have a system with more 390 than one CPU, say Y. 391 392 If you say N here, the kernel will run on uni- and multiprocessor 393 machines, but will use only one CPU of a multiprocessor machine. If 394 you say Y here, the kernel will run on many, but not all, 395 uniprocessor machines. On a uniprocessor machine, the kernel 396 will run faster if you say N here. 397 398 Note that if you say Y here and choose architecture "586" or 399 "Pentium" under "Processor family", the kernel will not work on 486 400 architectures. Similarly, multiprocessor kernels for the "PPro" 401 architecture may not work on all Pentium based boards. 402 403 People using multiprocessor machines who say Y here should also say 404 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 405 Management" code will be disabled if you say Y here. 406 407 See also <file:Documentation/x86/i386/IO-APIC.rst>, 408 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 409 <http://www.tldp.org/docs.html#howto>. 410 411 If you don't know what to do here, say N. 412 413config X86_FEATURE_NAMES 414 bool "Processor feature human-readable names" if EMBEDDED 415 default y 416 ---help--- 417 This option compiles in a table of x86 feature bits and corresponding 418 names. This is required to support /proc/cpuinfo and a few kernel 419 messages. You can disable this to save space, at the expense of 420 making those few kernel messages show numeric feature bits instead. 421 422 If in doubt, say Y. 423 424config X86_X2APIC 425 bool "Support x2apic" 426 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 427 ---help--- 428 This enables x2apic support on CPUs that have this feature. 429 430 This allows 32-bit apic IDs (so it can support very large systems), 431 and accesses the local apic via MSRs not via mmio. 432 433 If you don't know what to do here, say N. 434 435config X86_MPPARSE 436 bool "Enable MPS table" if ACPI || SFI 437 default y 438 depends on X86_LOCAL_APIC 439 ---help--- 440 For old smp systems that do not have proper acpi support. Newer systems 441 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 442 443config GOLDFISH 444 def_bool y 445 depends on X86_GOLDFISH 446 447config RETPOLINE 448 bool "Avoid speculative indirect branches in kernel" 449 default y 450 select STACK_VALIDATION if HAVE_STACK_VALIDATION 451 help 452 Compile kernel with the retpoline compiler options to guard against 453 kernel-to-user data leaks by avoiding speculative indirect 454 branches. Requires a compiler with -mindirect-branch=thunk-extern 455 support for full protection. The kernel may run slower. 456 457config X86_CPU_RESCTRL 458 bool "x86 CPU resource control support" 459 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 460 select KERNFS 461 select PROC_CPU_RESCTRL if PROC_FS 462 help 463 Enable x86 CPU resource control support. 464 465 Provide support for the allocation and monitoring of system resources 466 usage by the CPU. 467 468 Intel calls this Intel Resource Director Technology 469 (Intel(R) RDT). More information about RDT can be found in the 470 Intel x86 Architecture Software Developer Manual. 471 472 AMD calls this AMD Platform Quality of Service (AMD QoS). 473 More information about AMD QoS can be found in the AMD64 Technology 474 Platform Quality of Service Extensions manual. 475 476 Say N if unsure. 477 478if X86_32 479config X86_BIGSMP 480 bool "Support for big SMP systems with more than 8 CPUs" 481 depends on SMP 482 ---help--- 483 This option is needed for the systems that have more than 8 CPUs. 484 485config X86_EXTENDED_PLATFORM 486 bool "Support for extended (non-PC) x86 platforms" 487 default y 488 ---help--- 489 If you disable this option then the kernel will only support 490 standard PC platforms. (which covers the vast majority of 491 systems out there.) 492 493 If you enable this option then you'll be able to select support 494 for the following (non-PC) 32 bit x86 platforms: 495 Goldfish (Android emulator) 496 AMD Elan 497 RDC R-321x SoC 498 SGI 320/540 (Visual Workstation) 499 STA2X11-based (e.g. Northville) 500 Moorestown MID devices 501 502 If you have one of these systems, or if you want to build a 503 generic distribution kernel, say Y here - otherwise say N. 504endif 505 506if X86_64 507config X86_EXTENDED_PLATFORM 508 bool "Support for extended (non-PC) x86 platforms" 509 default y 510 ---help--- 511 If you disable this option then the kernel will only support 512 standard PC platforms. (which covers the vast majority of 513 systems out there.) 514 515 If you enable this option then you'll be able to select support 516 for the following (non-PC) 64 bit x86 platforms: 517 Numascale NumaChip 518 ScaleMP vSMP 519 SGI Ultraviolet 520 521 If you have one of these systems, or if you want to build a 522 generic distribution kernel, say Y here - otherwise say N. 523endif 524# This is an alphabetically sorted list of 64 bit extended platforms 525# Please maintain the alphabetic order if and when there are additions 526config X86_NUMACHIP 527 bool "Numascale NumaChip" 528 depends on X86_64 529 depends on X86_EXTENDED_PLATFORM 530 depends on NUMA 531 depends on SMP 532 depends on X86_X2APIC 533 depends on PCI_MMCONFIG 534 ---help--- 535 Adds support for Numascale NumaChip large-SMP systems. Needed to 536 enable more than ~168 cores. 537 If you don't have one of these, you should say N here. 538 539config X86_VSMP 540 bool "ScaleMP vSMP" 541 select HYPERVISOR_GUEST 542 select PARAVIRT 543 depends on X86_64 && PCI 544 depends on X86_EXTENDED_PLATFORM 545 depends on SMP 546 ---help--- 547 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 548 supposed to run on these EM64T-based machines. Only choose this option 549 if you have one of these machines. 550 551config X86_UV 552 bool "SGI Ultraviolet" 553 depends on X86_64 554 depends on X86_EXTENDED_PLATFORM 555 depends on NUMA 556 depends on EFI 557 depends on X86_X2APIC 558 depends on PCI 559 ---help--- 560 This option is needed in order to support SGI Ultraviolet systems. 561 If you don't have one of these, you should say N here. 562 563# Following is an alphabetically sorted list of 32 bit extended platforms 564# Please maintain the alphabetic order if and when there are additions 565 566config X86_GOLDFISH 567 bool "Goldfish (Virtual Platform)" 568 depends on X86_EXTENDED_PLATFORM 569 ---help--- 570 Enable support for the Goldfish virtual platform used primarily 571 for Android development. Unless you are building for the Android 572 Goldfish emulator say N here. 573 574config X86_INTEL_CE 575 bool "CE4100 TV platform" 576 depends on PCI 577 depends on PCI_GODIRECT 578 depends on X86_IO_APIC 579 depends on X86_32 580 depends on X86_EXTENDED_PLATFORM 581 select X86_REBOOTFIXUPS 582 select OF 583 select OF_EARLY_FLATTREE 584 ---help--- 585 Select for the Intel CE media processor (CE4100) SOC. 586 This option compiles in support for the CE4100 SOC for settop 587 boxes and media devices. 588 589config X86_INTEL_MID 590 bool "Intel MID platform support" 591 depends on X86_EXTENDED_PLATFORM 592 depends on X86_PLATFORM_DEVICES 593 depends on PCI 594 depends on X86_64 || (PCI_GOANY && X86_32) 595 depends on X86_IO_APIC 596 select SFI 597 select I2C 598 select DW_APB_TIMER 599 select APB_TIMER 600 select INTEL_SCU_PCI 601 select MFD_INTEL_MSIC 602 ---help--- 603 Select to build a kernel capable of supporting Intel MID (Mobile 604 Internet Device) platform systems which do not have the PCI legacy 605 interfaces. If you are building for a PC class system say N here. 606 607 Intel MID platforms are based on an Intel processor and chipset which 608 consume less power than most of the x86 derivatives. 609 610config X86_INTEL_QUARK 611 bool "Intel Quark platform support" 612 depends on X86_32 613 depends on X86_EXTENDED_PLATFORM 614 depends on X86_PLATFORM_DEVICES 615 depends on X86_TSC 616 depends on PCI 617 depends on PCI_GOANY 618 depends on X86_IO_APIC 619 select IOSF_MBI 620 select INTEL_IMR 621 select COMMON_CLK 622 ---help--- 623 Select to include support for Quark X1000 SoC. 624 Say Y here if you have a Quark based system such as the Arduino 625 compatible Intel Galileo. 626 627config X86_INTEL_LPSS 628 bool "Intel Low Power Subsystem Support" 629 depends on X86 && ACPI && PCI 630 select COMMON_CLK 631 select PINCTRL 632 select IOSF_MBI 633 ---help--- 634 Select to build support for Intel Low Power Subsystem such as 635 found on Intel Lynxpoint PCH. Selecting this option enables 636 things like clock tree (common clock framework) and pincontrol 637 which are needed by the LPSS peripheral drivers. 638 639config X86_AMD_PLATFORM_DEVICE 640 bool "AMD ACPI2Platform devices support" 641 depends on ACPI 642 select COMMON_CLK 643 select PINCTRL 644 ---help--- 645 Select to interpret AMD specific ACPI device to platform device 646 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 647 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 648 implemented under PINCTRL subsystem. 649 650config IOSF_MBI 651 tristate "Intel SoC IOSF Sideband support for SoC platforms" 652 depends on PCI 653 ---help--- 654 This option enables sideband register access support for Intel SoC 655 platforms. On these platforms the IOSF sideband is used in lieu of 656 MSR's for some register accesses, mostly but not limited to thermal 657 and power. Drivers may query the availability of this device to 658 determine if they need the sideband in order to work on these 659 platforms. The sideband is available on the following SoC products. 660 This list is not meant to be exclusive. 661 - BayTrail 662 - Braswell 663 - Quark 664 665 You should say Y if you are running a kernel on one of these SoC's. 666 667config IOSF_MBI_DEBUG 668 bool "Enable IOSF sideband access through debugfs" 669 depends on IOSF_MBI && DEBUG_FS 670 ---help--- 671 Select this option to expose the IOSF sideband access registers (MCR, 672 MDR, MCRX) through debugfs to write and read register information from 673 different units on the SoC. This is most useful for obtaining device 674 state information for debug and analysis. As this is a general access 675 mechanism, users of this option would have specific knowledge of the 676 device they want to access. 677 678 If you don't require the option or are in doubt, say N. 679 680config X86_RDC321X 681 bool "RDC R-321x SoC" 682 depends on X86_32 683 depends on X86_EXTENDED_PLATFORM 684 select M486 685 select X86_REBOOTFIXUPS 686 ---help--- 687 This option is needed for RDC R-321x system-on-chip, also known 688 as R-8610-(G). 689 If you don't have one of these chips, you should say N here. 690 691config X86_32_NON_STANDARD 692 bool "Support non-standard 32-bit SMP architectures" 693 depends on X86_32 && SMP 694 depends on X86_EXTENDED_PLATFORM 695 ---help--- 696 This option compiles in the bigsmp and STA2X11 default 697 subarchitectures. It is intended for a generic binary 698 kernel. If you select them all, kernel will probe it one by 699 one and will fallback to default. 700 701# Alphabetically sorted list of Non standard 32 bit platforms 702 703config X86_SUPPORTS_MEMORY_FAILURE 704 def_bool y 705 # MCE code calls memory_failure(): 706 depends on X86_MCE 707 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 708 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 709 depends on X86_64 || !SPARSEMEM 710 select ARCH_SUPPORTS_MEMORY_FAILURE 711 712config STA2X11 713 bool "STA2X11 Companion Chip Support" 714 depends on X86_32_NON_STANDARD && PCI 715 select SWIOTLB 716 select MFD_STA2X11 717 select GPIOLIB 718 ---help--- 719 This adds support for boards based on the STA2X11 IO-Hub, 720 a.k.a. "ConneXt". The chip is used in place of the standard 721 PC chipset, so all "standard" peripherals are missing. If this 722 option is selected the kernel will still be able to boot on 723 standard PC machines. 724 725config X86_32_IRIS 726 tristate "Eurobraille/Iris poweroff module" 727 depends on X86_32 728 ---help--- 729 The Iris machines from EuroBraille do not have APM or ACPI support 730 to shut themselves down properly. A special I/O sequence is 731 needed to do so, which is what this module does at 732 kernel shutdown. 733 734 This is only for Iris machines from EuroBraille. 735 736 If unused, say N. 737 738config SCHED_OMIT_FRAME_POINTER 739 def_bool y 740 prompt "Single-depth WCHAN output" 741 depends on X86 742 ---help--- 743 Calculate simpler /proc/<PID>/wchan values. If this option 744 is disabled then wchan values will recurse back to the 745 caller function. This provides more accurate wchan values, 746 at the expense of slightly more scheduling overhead. 747 748 If in doubt, say "Y". 749 750menuconfig HYPERVISOR_GUEST 751 bool "Linux guest support" 752 ---help--- 753 Say Y here to enable options for running Linux under various hyper- 754 visors. This option enables basic hypervisor detection and platform 755 setup. 756 757 If you say N, all options in this submenu will be skipped and 758 disabled, and Linux guest support won't be built in. 759 760if HYPERVISOR_GUEST 761 762config PARAVIRT 763 bool "Enable paravirtualization code" 764 ---help--- 765 This changes the kernel so it can modify itself when it is run 766 under a hypervisor, potentially improving performance significantly 767 over full virtualization. However, when run without a hypervisor 768 the kernel is theoretically slower and slightly larger. 769 770config PARAVIRT_XXL 771 bool 772 773config PARAVIRT_DEBUG 774 bool "paravirt-ops debugging" 775 depends on PARAVIRT && DEBUG_KERNEL 776 ---help--- 777 Enable to debug paravirt_ops internals. Specifically, BUG if 778 a paravirt_op is missing when it is called. 779 780config PARAVIRT_SPINLOCKS 781 bool "Paravirtualization layer for spinlocks" 782 depends on PARAVIRT && SMP 783 ---help--- 784 Paravirtualized spinlocks allow a pvops backend to replace the 785 spinlock implementation with something virtualization-friendly 786 (for example, block the virtual CPU rather than spinning). 787 788 It has a minimal impact on native kernels and gives a nice performance 789 benefit on paravirtualized KVM / Xen kernels. 790 791 If you are unsure how to answer this question, answer Y. 792 793config X86_HV_CALLBACK_VECTOR 794 def_bool n 795 796source "arch/x86/xen/Kconfig" 797 798config KVM_GUEST 799 bool "KVM Guest support (including kvmclock)" 800 depends on PARAVIRT 801 select PARAVIRT_CLOCK 802 select ARCH_CPUIDLE_HALTPOLL 803 default y 804 ---help--- 805 This option enables various optimizations for running under the KVM 806 hypervisor. It includes a paravirtualized clock, so that instead 807 of relying on a PIT (or probably other) emulation by the 808 underlying device model, the host provides the guest with 809 timing infrastructure such as time of day, and system time 810 811config ARCH_CPUIDLE_HALTPOLL 812 def_bool n 813 prompt "Disable host haltpoll when loading haltpoll driver" 814 help 815 If virtualized under KVM, disable host haltpoll. 816 817config PVH 818 bool "Support for running PVH guests" 819 ---help--- 820 This option enables the PVH entry point for guest virtual machines 821 as specified in the x86/HVM direct boot ABI. 822 823config KVM_DEBUG_FS 824 bool "Enable debug information for KVM Guests in debugfs" 825 depends on KVM_GUEST && DEBUG_FS 826 ---help--- 827 This option enables collection of various statistics for KVM guest. 828 Statistics are displayed in debugfs filesystem. Enabling this option 829 may incur significant overhead. 830 831config PARAVIRT_TIME_ACCOUNTING 832 bool "Paravirtual steal time accounting" 833 depends on PARAVIRT 834 ---help--- 835 Select this option to enable fine granularity task steal time 836 accounting. Time spent executing other tasks in parallel with 837 the current vCPU is discounted from the vCPU power. To account for 838 that, there can be a small performance impact. 839 840 If in doubt, say N here. 841 842config PARAVIRT_CLOCK 843 bool 844 845config JAILHOUSE_GUEST 846 bool "Jailhouse non-root cell support" 847 depends on X86_64 && PCI 848 select X86_PM_TIMER 849 ---help--- 850 This option allows to run Linux as guest in a Jailhouse non-root 851 cell. You can leave this option disabled if you only want to start 852 Jailhouse and run Linux afterwards in the root cell. 853 854config ACRN_GUEST 855 bool "ACRN Guest support" 856 depends on X86_64 857 select X86_HV_CALLBACK_VECTOR 858 help 859 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 860 a flexible, lightweight reference open-source hypervisor, built with 861 real-time and safety-criticality in mind. It is built for embedded 862 IOT with small footprint and real-time features. More details can be 863 found in https://projectacrn.org/. 864 865endif #HYPERVISOR_GUEST 866 867source "arch/x86/Kconfig.cpu" 868 869config HPET_TIMER 870 def_bool X86_64 871 prompt "HPET Timer Support" if X86_32 872 ---help--- 873 Use the IA-PC HPET (High Precision Event Timer) to manage 874 time in preference to the PIT and RTC, if a HPET is 875 present. 876 HPET is the next generation timer replacing legacy 8254s. 877 The HPET provides a stable time base on SMP 878 systems, unlike the TSC, but it is more expensive to access, 879 as it is off-chip. The interface used is documented 880 in the HPET spec, revision 1. 881 882 You can safely choose Y here. However, HPET will only be 883 activated if the platform and the BIOS support this feature. 884 Otherwise the 8254 will be used for timing services. 885 886 Choose N to continue using the legacy 8254 timer. 887 888config HPET_EMULATE_RTC 889 def_bool y 890 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 891 892config APB_TIMER 893 def_bool y if X86_INTEL_MID 894 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 895 select DW_APB_TIMER 896 depends on X86_INTEL_MID && SFI 897 help 898 APB timer is the replacement for 8254, HPET on X86 MID platforms. 899 The APBT provides a stable time base on SMP 900 systems, unlike the TSC, but it is more expensive to access, 901 as it is off-chip. APB timers are always running regardless of CPU 902 C states, they are used as per CPU clockevent device when possible. 903 904# Mark as expert because too many people got it wrong. 905# The code disables itself when not needed. 906config DMI 907 default y 908 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 909 bool "Enable DMI scanning" if EXPERT 910 ---help--- 911 Enabled scanning of DMI to identify machine quirks. Say Y 912 here unless you have verified that your setup is not 913 affected by entries in the DMI blacklist. Required by PNP 914 BIOS code. 915 916config GART_IOMMU 917 bool "Old AMD GART IOMMU support" 918 select IOMMU_HELPER 919 select SWIOTLB 920 depends on X86_64 && PCI && AMD_NB 921 ---help--- 922 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 923 GART based hardware IOMMUs. 924 925 The GART supports full DMA access for devices with 32-bit access 926 limitations, on systems with more than 3 GB. This is usually needed 927 for USB, sound, many IDE/SATA chipsets and some other devices. 928 929 Newer systems typically have a modern AMD IOMMU, supported via 930 the CONFIG_AMD_IOMMU=y config option. 931 932 In normal configurations this driver is only active when needed: 933 there's more than 3 GB of memory and the system contains a 934 32-bit limited device. 935 936 If unsure, say Y. 937 938config MAXSMP 939 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 940 depends on X86_64 && SMP && DEBUG_KERNEL 941 select CPUMASK_OFFSTACK 942 ---help--- 943 Enable maximum number of CPUS and NUMA Nodes for this architecture. 944 If unsure, say N. 945 946# 947# The maximum number of CPUs supported: 948# 949# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 950# and which can be configured interactively in the 951# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 952# 953# The ranges are different on 32-bit and 64-bit kernels, depending on 954# hardware capabilities and scalability features of the kernel. 955# 956# ( If MAXSMP is enabled we just use the highest possible value and disable 957# interactive configuration. ) 958# 959 960config NR_CPUS_RANGE_BEGIN 961 int 962 default NR_CPUS_RANGE_END if MAXSMP 963 default 1 if !SMP 964 default 2 965 966config NR_CPUS_RANGE_END 967 int 968 depends on X86_32 969 default 64 if SMP && X86_BIGSMP 970 default 8 if SMP && !X86_BIGSMP 971 default 1 if !SMP 972 973config NR_CPUS_RANGE_END 974 int 975 depends on X86_64 976 default 8192 if SMP && CPUMASK_OFFSTACK 977 default 512 if SMP && !CPUMASK_OFFSTACK 978 default 1 if !SMP 979 980config NR_CPUS_DEFAULT 981 int 982 depends on X86_32 983 default 32 if X86_BIGSMP 984 default 8 if SMP 985 default 1 if !SMP 986 987config NR_CPUS_DEFAULT 988 int 989 depends on X86_64 990 default 8192 if MAXSMP 991 default 64 if SMP 992 default 1 if !SMP 993 994config NR_CPUS 995 int "Maximum number of CPUs" if SMP && !MAXSMP 996 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 997 default NR_CPUS_DEFAULT 998 ---help--- 999 This allows you to specify the maximum number of CPUs which this 1000 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1001 supported value is 8192, otherwise the maximum value is 512. The 1002 minimum value which makes sense is 2. 1003 1004 This is purely to save memory: each supported CPU adds about 8KB 1005 to the kernel image. 1006 1007config SCHED_SMT 1008 def_bool y if SMP 1009 1010config SCHED_MC 1011 def_bool y 1012 prompt "Multi-core scheduler support" 1013 depends on SMP 1014 ---help--- 1015 Multi-core scheduler support improves the CPU scheduler's decision 1016 making when dealing with multi-core CPU chips at a cost of slightly 1017 increased overhead in some places. If unsure say N here. 1018 1019config SCHED_MC_PRIO 1020 bool "CPU core priorities scheduler support" 1021 depends on SCHED_MC && CPU_SUP_INTEL 1022 select X86_INTEL_PSTATE 1023 select CPU_FREQ 1024 default y 1025 ---help--- 1026 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1027 core ordering determined at manufacturing time, which allows 1028 certain cores to reach higher turbo frequencies (when running 1029 single threaded workloads) than others. 1030 1031 Enabling this kernel feature teaches the scheduler about 1032 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1033 scheduler's CPU selection logic accordingly, so that higher 1034 overall system performance can be achieved. 1035 1036 This feature will have no effect on CPUs without this feature. 1037 1038 If unsure say Y here. 1039 1040config UP_LATE_INIT 1041 def_bool y 1042 depends on !SMP && X86_LOCAL_APIC 1043 1044config X86_UP_APIC 1045 bool "Local APIC support on uniprocessors" if !PCI_MSI 1046 default PCI_MSI 1047 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1048 ---help--- 1049 A local APIC (Advanced Programmable Interrupt Controller) is an 1050 integrated interrupt controller in the CPU. If you have a single-CPU 1051 system which has a processor with a local APIC, you can say Y here to 1052 enable and use it. If you say Y here even though your machine doesn't 1053 have a local APIC, then the kernel will still run with no slowdown at 1054 all. The local APIC supports CPU-generated self-interrupts (timer, 1055 performance counters), and the NMI watchdog which detects hard 1056 lockups. 1057 1058config X86_UP_IOAPIC 1059 bool "IO-APIC support on uniprocessors" 1060 depends on X86_UP_APIC 1061 ---help--- 1062 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1063 SMP-capable replacement for PC-style interrupt controllers. Most 1064 SMP systems and many recent uniprocessor systems have one. 1065 1066 If you have a single-CPU system with an IO-APIC, you can say Y here 1067 to use it. If you say Y here even though your machine doesn't have 1068 an IO-APIC, then the kernel will still run with no slowdown at all. 1069 1070config X86_LOCAL_APIC 1071 def_bool y 1072 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1073 select IRQ_DOMAIN_HIERARCHY 1074 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1075 1076config X86_IO_APIC 1077 def_bool y 1078 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1079 1080config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1081 bool "Reroute for broken boot IRQs" 1082 depends on X86_IO_APIC 1083 ---help--- 1084 This option enables a workaround that fixes a source of 1085 spurious interrupts. This is recommended when threaded 1086 interrupt handling is used on systems where the generation of 1087 superfluous "boot interrupts" cannot be disabled. 1088 1089 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1090 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1091 kernel does during interrupt handling). On chipsets where this 1092 boot IRQ generation cannot be disabled, this workaround keeps 1093 the original IRQ line masked so that only the equivalent "boot 1094 IRQ" is delivered to the CPUs. The workaround also tells the 1095 kernel to set up the IRQ handler on the boot IRQ line. In this 1096 way only one interrupt is delivered to the kernel. Otherwise 1097 the spurious second interrupt may cause the kernel to bring 1098 down (vital) interrupt lines. 1099 1100 Only affects "broken" chipsets. Interrupt sharing may be 1101 increased on these systems. 1102 1103config X86_MCE 1104 bool "Machine Check / overheating reporting" 1105 select GENERIC_ALLOCATOR 1106 default y 1107 ---help--- 1108 Machine Check support allows the processor to notify the 1109 kernel if it detects a problem (e.g. overheating, data corruption). 1110 The action the kernel takes depends on the severity of the problem, 1111 ranging from warning messages to halting the machine. 1112 1113config X86_MCELOG_LEGACY 1114 bool "Support for deprecated /dev/mcelog character device" 1115 depends on X86_MCE 1116 ---help--- 1117 Enable support for /dev/mcelog which is needed by the old mcelog 1118 userspace logging daemon. Consider switching to the new generation 1119 rasdaemon solution. 1120 1121config X86_MCE_INTEL 1122 def_bool y 1123 prompt "Intel MCE features" 1124 depends on X86_MCE && X86_LOCAL_APIC 1125 ---help--- 1126 Additional support for intel specific MCE features such as 1127 the thermal monitor. 1128 1129config X86_MCE_AMD 1130 def_bool y 1131 prompt "AMD MCE features" 1132 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1133 ---help--- 1134 Additional support for AMD specific MCE features such as 1135 the DRAM Error Threshold. 1136 1137config X86_ANCIENT_MCE 1138 bool "Support for old Pentium 5 / WinChip machine checks" 1139 depends on X86_32 && X86_MCE 1140 ---help--- 1141 Include support for machine check handling on old Pentium 5 or WinChip 1142 systems. These typically need to be enabled explicitly on the command 1143 line. 1144 1145config X86_MCE_THRESHOLD 1146 depends on X86_MCE_AMD || X86_MCE_INTEL 1147 def_bool y 1148 1149config X86_MCE_INJECT 1150 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1151 tristate "Machine check injector support" 1152 ---help--- 1153 Provide support for injecting machine checks for testing purposes. 1154 If you don't know what a machine check is and you don't do kernel 1155 QA it is safe to say n. 1156 1157config X86_THERMAL_VECTOR 1158 def_bool y 1159 depends on X86_MCE_INTEL 1160 1161source "arch/x86/events/Kconfig" 1162 1163config X86_LEGACY_VM86 1164 bool "Legacy VM86 support" 1165 depends on X86_32 1166 ---help--- 1167 This option allows user programs to put the CPU into V8086 1168 mode, which is an 80286-era approximation of 16-bit real mode. 1169 1170 Some very old versions of X and/or vbetool require this option 1171 for user mode setting. Similarly, DOSEMU will use it if 1172 available to accelerate real mode DOS programs. However, any 1173 recent version of DOSEMU, X, or vbetool should be fully 1174 functional even without kernel VM86 support, as they will all 1175 fall back to software emulation. Nevertheless, if you are using 1176 a 16-bit DOS program where 16-bit performance matters, vm86 1177 mode might be faster than emulation and you might want to 1178 enable this option. 1179 1180 Note that any app that works on a 64-bit kernel is unlikely to 1181 need this option, as 64-bit kernels don't, and can't, support 1182 V8086 mode. This option is also unrelated to 16-bit protected 1183 mode and is not needed to run most 16-bit programs under Wine. 1184 1185 Enabling this option increases the complexity of the kernel 1186 and slows down exception handling a tiny bit. 1187 1188 If unsure, say N here. 1189 1190config VM86 1191 bool 1192 default X86_LEGACY_VM86 1193 1194config X86_16BIT 1195 bool "Enable support for 16-bit segments" if EXPERT 1196 default y 1197 depends on MODIFY_LDT_SYSCALL 1198 ---help--- 1199 This option is required by programs like Wine to run 16-bit 1200 protected mode legacy code on x86 processors. Disabling 1201 this option saves about 300 bytes on i386, or around 6K text 1202 plus 16K runtime memory on x86-64, 1203 1204config X86_ESPFIX32 1205 def_bool y 1206 depends on X86_16BIT && X86_32 1207 1208config X86_ESPFIX64 1209 def_bool y 1210 depends on X86_16BIT && X86_64 1211 1212config X86_VSYSCALL_EMULATION 1213 bool "Enable vsyscall emulation" if EXPERT 1214 default y 1215 depends on X86_64 1216 ---help--- 1217 This enables emulation of the legacy vsyscall page. Disabling 1218 it is roughly equivalent to booting with vsyscall=none, except 1219 that it will also disable the helpful warning if a program 1220 tries to use a vsyscall. With this option set to N, offending 1221 programs will just segfault, citing addresses of the form 1222 0xffffffffff600?00. 1223 1224 This option is required by many programs built before 2013, and 1225 care should be used even with newer programs if set to N. 1226 1227 Disabling this option saves about 7K of kernel size and 1228 possibly 4K of additional runtime pagetable memory. 1229 1230config X86_IOPL_IOPERM 1231 bool "IOPERM and IOPL Emulation" 1232 default y 1233 ---help--- 1234 This enables the ioperm() and iopl() syscalls which are necessary 1235 for legacy applications. 1236 1237 Legacy IOPL support is an overbroad mechanism which allows user 1238 space aside of accessing all 65536 I/O ports also to disable 1239 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1240 capabilities and permission from potentially active security 1241 modules. 1242 1243 The emulation restricts the functionality of the syscall to 1244 only allowing the full range I/O port access, but prevents the 1245 ability to disable interrupts from user space which would be 1246 granted if the hardware IOPL mechanism would be used. 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 default y 1487 select DYNAMIC_MEMORY_LAYOUT 1488 select SPARSEMEM_VMEMMAP 1489 depends on X86_64 1490 ---help--- 1491 5-level paging enables access to larger address space: 1492 upto 128 PiB of virtual address space and 4 PiB of 1493 physical address space. 1494 1495 It will be supported by future Intel CPUs. 1496 1497 A kernel with the option enabled can be booted on machines that 1498 support 4- or 5-level paging. 1499 1500 See Documentation/x86/x86_64/5level-paging.rst for more 1501 information. 1502 1503 Say N if unsure. 1504 1505config X86_DIRECT_GBPAGES 1506 def_bool y 1507 depends on X86_64 1508 ---help--- 1509 Certain kernel features effectively disable kernel 1510 linear 1 GB mappings (even if the CPU otherwise 1511 supports them), so don't confuse the user by printing 1512 that we have them enabled. 1513 1514config X86_CPA_STATISTICS 1515 bool "Enable statistic for Change Page Attribute" 1516 depends on DEBUG_FS 1517 ---help--- 1518 Expose statistics about the Change Page Attribute mechanism, which 1519 helps to determine the effectiveness of preserving large and huge 1520 page mappings when mapping protections are changed. 1521 1522config AMD_MEM_ENCRYPT 1523 bool "AMD Secure Memory Encryption (SME) support" 1524 depends on X86_64 && CPU_SUP_AMD 1525 select DYNAMIC_PHYSICAL_MASK 1526 select ARCH_USE_MEMREMAP_PROT 1527 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1528 ---help--- 1529 Say yes to enable support for the encryption of system memory. 1530 This requires an AMD processor that supports Secure Memory 1531 Encryption (SME). 1532 1533config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1534 bool "Activate AMD Secure Memory Encryption (SME) by default" 1535 default y 1536 depends on AMD_MEM_ENCRYPT 1537 ---help--- 1538 Say yes to have system memory encrypted by default if running on 1539 an AMD processor that supports Secure Memory Encryption (SME). 1540 1541 If set to Y, then the encryption of system memory can be 1542 deactivated with the mem_encrypt=off command line option. 1543 1544 If set to N, then the encryption of system memory can be 1545 activated with the mem_encrypt=on command line option. 1546 1547# Common NUMA Features 1548config NUMA 1549 bool "NUMA Memory Allocation and Scheduler Support" 1550 depends on SMP 1551 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1552 default y if X86_BIGSMP 1553 ---help--- 1554 Enable NUMA (Non-Uniform Memory Access) support. 1555 1556 The kernel will try to allocate memory used by a CPU on the 1557 local memory controller of the CPU and add some more 1558 NUMA awareness to the kernel. 1559 1560 For 64-bit this is recommended if the system is Intel Core i7 1561 (or later), AMD Opteron, or EM64T NUMA. 1562 1563 For 32-bit this is only needed if you boot a 32-bit 1564 kernel on a 64-bit NUMA platform. 1565 1566 Otherwise, you should say N. 1567 1568config AMD_NUMA 1569 def_bool y 1570 prompt "Old style AMD Opteron NUMA detection" 1571 depends on X86_64 && NUMA && PCI 1572 ---help--- 1573 Enable AMD NUMA node topology detection. You should say Y here if 1574 you have a multi processor AMD system. This uses an old method to 1575 read the NUMA configuration directly from the builtin Northbridge 1576 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1577 which also takes priority if both are compiled in. 1578 1579config X86_64_ACPI_NUMA 1580 def_bool y 1581 prompt "ACPI NUMA detection" 1582 depends on X86_64 && NUMA && ACPI && PCI 1583 select ACPI_NUMA 1584 ---help--- 1585 Enable ACPI SRAT based node topology detection. 1586 1587# Some NUMA nodes have memory ranges that span 1588# other nodes. Even though a pfn is valid and 1589# between a node's start and end pfns, it may not 1590# reside on that node. See memmap_init_zone() 1591# for details. 1592config NODES_SPAN_OTHER_NODES 1593 def_bool y 1594 depends on X86_64_ACPI_NUMA 1595 1596config NUMA_EMU 1597 bool "NUMA emulation" 1598 depends on NUMA 1599 ---help--- 1600 Enable NUMA emulation. A flat machine will be split 1601 into virtual nodes when booted with "numa=fake=N", where N is the 1602 number of nodes. This is only useful for debugging. 1603 1604config NODES_SHIFT 1605 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1606 range 1 10 1607 default "10" if MAXSMP 1608 default "6" if X86_64 1609 default "3" 1610 depends on NEED_MULTIPLE_NODES 1611 ---help--- 1612 Specify the maximum number of NUMA Nodes available on the target 1613 system. Increases memory reserved to accommodate various tables. 1614 1615config ARCH_FLATMEM_ENABLE 1616 def_bool y 1617 depends on X86_32 && !NUMA 1618 1619config ARCH_SPARSEMEM_ENABLE 1620 def_bool y 1621 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1622 select SPARSEMEM_STATIC if X86_32 1623 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1624 1625config ARCH_SPARSEMEM_DEFAULT 1626 def_bool X86_64 || (NUMA && X86_32) 1627 1628config ARCH_SELECT_MEMORY_MODEL 1629 def_bool y 1630 depends on ARCH_SPARSEMEM_ENABLE 1631 1632config ARCH_MEMORY_PROBE 1633 bool "Enable sysfs memory/probe interface" 1634 depends on X86_64 && MEMORY_HOTPLUG 1635 help 1636 This option enables a sysfs memory/probe interface for testing. 1637 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1638 If you are unsure how to answer this question, answer N. 1639 1640config ARCH_PROC_KCORE_TEXT 1641 def_bool y 1642 depends on X86_64 && PROC_KCORE 1643 1644config ILLEGAL_POINTER_VALUE 1645 hex 1646 default 0 if X86_32 1647 default 0xdead000000000000 if X86_64 1648 1649config X86_PMEM_LEGACY_DEVICE 1650 bool 1651 1652config X86_PMEM_LEGACY 1653 tristate "Support non-standard NVDIMMs and ADR protected memory" 1654 depends on PHYS_ADDR_T_64BIT 1655 depends on BLK_DEV 1656 select X86_PMEM_LEGACY_DEVICE 1657 select NUMA_KEEP_MEMINFO if NUMA 1658 select LIBNVDIMM 1659 help 1660 Treat memory marked using the non-standard e820 type of 12 as used 1661 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1662 The kernel will offer these regions to the 'pmem' driver so 1663 they can be used for persistent storage. 1664 1665 Say Y if unsure. 1666 1667config HIGHPTE 1668 bool "Allocate 3rd-level pagetables from highmem" 1669 depends on HIGHMEM 1670 ---help--- 1671 The VM uses one page table entry for each page of physical memory. 1672 For systems with a lot of RAM, this can be wasteful of precious 1673 low memory. Setting this option will put user-space page table 1674 entries in high memory. 1675 1676config X86_CHECK_BIOS_CORRUPTION 1677 bool "Check for low memory corruption" 1678 ---help--- 1679 Periodically check for memory corruption in low memory, which 1680 is suspected to be caused by BIOS. Even when enabled in the 1681 configuration, it is disabled at runtime. Enable it by 1682 setting "memory_corruption_check=1" on the kernel command 1683 line. By default it scans the low 64k of memory every 60 1684 seconds; see the memory_corruption_check_size and 1685 memory_corruption_check_period parameters in 1686 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1687 1688 When enabled with the default parameters, this option has 1689 almost no overhead, as it reserves a relatively small amount 1690 of memory and scans it infrequently. It both detects corruption 1691 and prevents it from affecting the running system. 1692 1693 It is, however, intended as a diagnostic tool; if repeatable 1694 BIOS-originated corruption always affects the same memory, 1695 you can use memmap= to prevent the kernel from using that 1696 memory. 1697 1698config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1699 bool "Set the default setting of memory_corruption_check" 1700 depends on X86_CHECK_BIOS_CORRUPTION 1701 default y 1702 ---help--- 1703 Set whether the default state of memory_corruption_check is 1704 on or off. 1705 1706config X86_RESERVE_LOW 1707 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1708 default 64 1709 range 4 640 1710 ---help--- 1711 Specify the amount of low memory to reserve for the BIOS. 1712 1713 The first page contains BIOS data structures that the kernel 1714 must not use, so that page must always be reserved. 1715 1716 By default we reserve the first 64K of physical RAM, as a 1717 number of BIOSes are known to corrupt that memory range 1718 during events such as suspend/resume or monitor cable 1719 insertion, so it must not be used by the kernel. 1720 1721 You can set this to 4 if you are absolutely sure that you 1722 trust the BIOS to get all its memory reservations and usages 1723 right. If you know your BIOS have problems beyond the 1724 default 64K area, you can set this to 640 to avoid using the 1725 entire low memory range. 1726 1727 If you have doubts about the BIOS (e.g. suspend/resume does 1728 not work or there's kernel crashes after certain hardware 1729 hotplug events) then you might want to enable 1730 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1731 typical corruption patterns. 1732 1733 Leave this to the default value of 64 if you are unsure. 1734 1735config MATH_EMULATION 1736 bool 1737 depends on MODIFY_LDT_SYSCALL 1738 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1739 ---help--- 1740 Linux can emulate a math coprocessor (used for floating point 1741 operations) if you don't have one. 486DX and Pentium processors have 1742 a math coprocessor built in, 486SX and 386 do not, unless you added 1743 a 487DX or 387, respectively. (The messages during boot time can 1744 give you some hints here ["man dmesg"].) Everyone needs either a 1745 coprocessor or this emulation. 1746 1747 If you don't have a math coprocessor, you need to say Y here; if you 1748 say Y here even though you have a coprocessor, the coprocessor will 1749 be used nevertheless. (This behavior can be changed with the kernel 1750 command line option "no387", which comes handy if your coprocessor 1751 is broken. Try "man bootparam" or see the documentation of your boot 1752 loader (lilo or loadlin) about how to pass options to the kernel at 1753 boot time.) This means that it is a good idea to say Y here if you 1754 intend to use this kernel on different machines. 1755 1756 More information about the internals of the Linux math coprocessor 1757 emulation can be found in <file:arch/x86/math-emu/README>. 1758 1759 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1760 kernel, it won't hurt. 1761 1762config MTRR 1763 def_bool y 1764 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1765 ---help--- 1766 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1767 the Memory Type Range Registers (MTRRs) may be used to control 1768 processor access to memory ranges. This is most useful if you have 1769 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1770 allows bus write transfers to be combined into a larger transfer 1771 before bursting over the PCI/AGP bus. This can increase performance 1772 of image write operations 2.5 times or more. Saying Y here creates a 1773 /proc/mtrr file which may be used to manipulate your processor's 1774 MTRRs. Typically the X server should use this. 1775 1776 This code has a reasonably generic interface so that similar 1777 control registers on other processors can be easily supported 1778 as well: 1779 1780 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1781 Registers (ARRs) which provide a similar functionality to MTRRs. For 1782 these, the ARRs are used to emulate the MTRRs. 1783 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1784 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1785 write-combining. All of these processors are supported by this code 1786 and it makes sense to say Y here if you have one of them. 1787 1788 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1789 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1790 can lead to all sorts of problems, so it's good to say Y here. 1791 1792 You can safely say Y even if your machine doesn't have MTRRs, you'll 1793 just add about 9 KB to your kernel. 1794 1795 See <file:Documentation/x86/mtrr.rst> for more information. 1796 1797config MTRR_SANITIZER 1798 def_bool y 1799 prompt "MTRR cleanup support" 1800 depends on MTRR 1801 ---help--- 1802 Convert MTRR layout from continuous to discrete, so X drivers can 1803 add writeback entries. 1804 1805 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1806 The largest mtrr entry size for a continuous block can be set with 1807 mtrr_chunk_size. 1808 1809 If unsure, say Y. 1810 1811config MTRR_SANITIZER_ENABLE_DEFAULT 1812 int "MTRR cleanup enable value (0-1)" 1813 range 0 1 1814 default "0" 1815 depends on MTRR_SANITIZER 1816 ---help--- 1817 Enable mtrr cleanup default value 1818 1819config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1820 int "MTRR cleanup spare reg num (0-7)" 1821 range 0 7 1822 default "1" 1823 depends on MTRR_SANITIZER 1824 ---help--- 1825 mtrr cleanup spare entries default, it can be changed via 1826 mtrr_spare_reg_nr=N on the kernel command line. 1827 1828config X86_PAT 1829 def_bool y 1830 prompt "x86 PAT support" if EXPERT 1831 depends on MTRR 1832 ---help--- 1833 Use PAT attributes to setup page level cache control. 1834 1835 PATs are the modern equivalents of MTRRs and are much more 1836 flexible than MTRRs. 1837 1838 Say N here if you see bootup problems (boot crash, boot hang, 1839 spontaneous reboots) or a non-working video driver. 1840 1841 If unsure, say Y. 1842 1843config ARCH_USES_PG_UNCACHED 1844 def_bool y 1845 depends on X86_PAT 1846 1847config ARCH_RANDOM 1848 def_bool y 1849 prompt "x86 architectural random number generator" if EXPERT 1850 ---help--- 1851 Enable the x86 architectural RDRAND instruction 1852 (Intel Bull Mountain technology) to generate random numbers. 1853 If supported, this is a high bandwidth, cryptographically 1854 secure hardware random number generator. 1855 1856config X86_SMAP 1857 def_bool y 1858 prompt "Supervisor Mode Access Prevention" if EXPERT 1859 ---help--- 1860 Supervisor Mode Access Prevention (SMAP) is a security 1861 feature in newer Intel processors. There is a small 1862 performance cost if this enabled and turned on; there is 1863 also a small increase in the kernel size if this is enabled. 1864 1865 If unsure, say Y. 1866 1867config X86_UMIP 1868 def_bool y 1869 prompt "User Mode Instruction Prevention" if EXPERT 1870 ---help--- 1871 User Mode Instruction Prevention (UMIP) is a security feature in 1872 some x86 processors. If enabled, a general protection fault is 1873 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1874 executed in user mode. These instructions unnecessarily expose 1875 information about the hardware state. 1876 1877 The vast majority of applications do not use these instructions. 1878 For the very few that do, software emulation is provided in 1879 specific cases in protected and virtual-8086 modes. Emulated 1880 results are dummy. 1881 1882config X86_INTEL_MEMORY_PROTECTION_KEYS 1883 prompt "Memory Protection Keys" 1884 def_bool y 1885 # Note: only available in 64-bit mode 1886 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1887 select ARCH_USES_HIGH_VMA_FLAGS 1888 select ARCH_HAS_PKEYS 1889 ---help--- 1890 Memory Protection Keys provides a mechanism for enforcing 1891 page-based protections, but without requiring modification of the 1892 page tables when an application changes protection domains. 1893 1894 For details, see Documentation/core-api/protection-keys.rst 1895 1896 If unsure, say y. 1897 1898choice 1899 prompt "TSX enable mode" 1900 depends on CPU_SUP_INTEL 1901 default X86_INTEL_TSX_MODE_OFF 1902 help 1903 Intel's TSX (Transactional Synchronization Extensions) feature 1904 allows to optimize locking protocols through lock elision which 1905 can lead to a noticeable performance boost. 1906 1907 On the other hand it has been shown that TSX can be exploited 1908 to form side channel attacks (e.g. TAA) and chances are there 1909 will be more of those attacks discovered in the future. 1910 1911 Therefore TSX is not enabled by default (aka tsx=off). An admin 1912 might override this decision by tsx=on the command line parameter. 1913 Even with TSX enabled, the kernel will attempt to enable the best 1914 possible TAA mitigation setting depending on the microcode available 1915 for the particular machine. 1916 1917 This option allows to set the default tsx mode between tsx=on, =off 1918 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1919 details. 1920 1921 Say off if not sure, auto if TSX is in use but it should be used on safe 1922 platforms or on if TSX is in use and the security aspect of tsx is not 1923 relevant. 1924 1925config X86_INTEL_TSX_MODE_OFF 1926 bool "off" 1927 help 1928 TSX is disabled if possible - equals to tsx=off command line parameter. 1929 1930config X86_INTEL_TSX_MODE_ON 1931 bool "on" 1932 help 1933 TSX is always enabled on TSX capable HW - equals the tsx=on command 1934 line parameter. 1935 1936config X86_INTEL_TSX_MODE_AUTO 1937 bool "auto" 1938 help 1939 TSX is enabled on TSX capable HW that is believed to be safe against 1940 side channel attacks- equals the tsx=auto command line parameter. 1941endchoice 1942 1943config EFI 1944 bool "EFI runtime service support" 1945 depends on ACPI 1946 select UCS2_STRING 1947 select EFI_RUNTIME_WRAPPERS 1948 ---help--- 1949 This enables the kernel to use EFI runtime services that are 1950 available (such as the EFI variable services). 1951 1952 This option is only useful on systems that have EFI firmware. 1953 In addition, you should use the latest ELILO loader available 1954 at <http://elilo.sourceforge.net> in order to take advantage 1955 of EFI runtime services. However, even with this option, the 1956 resultant kernel should continue to boot on existing non-EFI 1957 platforms. 1958 1959config EFI_STUB 1960 bool "EFI stub support" 1961 depends on EFI && !X86_USE_3DNOW 1962 depends on $(cc-option,-mabi=ms) || X86_32 1963 select RELOCATABLE 1964 ---help--- 1965 This kernel feature allows a bzImage to be loaded directly 1966 by EFI firmware without the use of a bootloader. 1967 1968 See Documentation/admin-guide/efi-stub.rst for more information. 1969 1970config EFI_MIXED 1971 bool "EFI mixed-mode support" 1972 depends on EFI_STUB && X86_64 1973 ---help--- 1974 Enabling this feature allows a 64-bit kernel to be booted 1975 on a 32-bit firmware, provided that your CPU supports 64-bit 1976 mode. 1977 1978 Note that it is not possible to boot a mixed-mode enabled 1979 kernel via the EFI boot stub - a bootloader that supports 1980 the EFI handover protocol must be used. 1981 1982 If unsure, say N. 1983 1984config SECCOMP 1985 def_bool y 1986 prompt "Enable seccomp to safely compute untrusted bytecode" 1987 ---help--- 1988 This kernel feature is useful for number crunching applications 1989 that may need to compute untrusted bytecode during their 1990 execution. By using pipes or other transports made available to 1991 the process as file descriptors supporting the read/write 1992 syscalls, it's possible to isolate those applications in 1993 their own address space using seccomp. Once seccomp is 1994 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 1995 and the task is only allowed to execute a few safe syscalls 1996 defined by each seccomp mode. 1997 1998 If unsure, say Y. Only embedded should say N here. 1999 2000source "kernel/Kconfig.hz" 2001 2002config KEXEC 2003 bool "kexec system call" 2004 select KEXEC_CORE 2005 ---help--- 2006 kexec is a system call that implements the ability to shutdown your 2007 current kernel, and to start another kernel. It is like a reboot 2008 but it is independent of the system firmware. And like a reboot 2009 you can start any kernel with it, not just Linux. 2010 2011 The name comes from the similarity to the exec system call. 2012 2013 It is an ongoing process to be certain the hardware in a machine 2014 is properly shutdown, so do not be surprised if this code does not 2015 initially work for you. As of this writing the exact hardware 2016 interface is strongly in flux, so no good recommendation can be 2017 made. 2018 2019config KEXEC_FILE 2020 bool "kexec file based system call" 2021 select KEXEC_CORE 2022 select BUILD_BIN2C 2023 depends on X86_64 2024 depends on CRYPTO=y 2025 depends on CRYPTO_SHA256=y 2026 ---help--- 2027 This is new version of kexec system call. This system call is 2028 file based and takes file descriptors as system call argument 2029 for kernel and initramfs as opposed to list of segments as 2030 accepted by previous system call. 2031 2032config ARCH_HAS_KEXEC_PURGATORY 2033 def_bool KEXEC_FILE 2034 2035config KEXEC_SIG 2036 bool "Verify kernel signature during kexec_file_load() syscall" 2037 depends on KEXEC_FILE 2038 ---help--- 2039 2040 This option makes the kexec_file_load() syscall check for a valid 2041 signature of the kernel image. The image can still be loaded without 2042 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2043 there's a signature that we can check, then it must be valid. 2044 2045 In addition to this option, you need to enable signature 2046 verification for the corresponding kernel image type being 2047 loaded in order for this to work. 2048 2049config KEXEC_SIG_FORCE 2050 bool "Require a valid signature in kexec_file_load() syscall" 2051 depends on KEXEC_SIG 2052 ---help--- 2053 This option makes kernel signature verification mandatory for 2054 the kexec_file_load() syscall. 2055 2056config KEXEC_BZIMAGE_VERIFY_SIG 2057 bool "Enable bzImage signature verification support" 2058 depends on KEXEC_SIG 2059 depends on SIGNED_PE_FILE_VERIFICATION 2060 select SYSTEM_TRUSTED_KEYRING 2061 ---help--- 2062 Enable bzImage signature verification support. 2063 2064config CRASH_DUMP 2065 bool "kernel crash dumps" 2066 depends on X86_64 || (X86_32 && HIGHMEM) 2067 ---help--- 2068 Generate crash dump after being started by kexec. 2069 This should be normally only set in special crash dump kernels 2070 which are loaded in the main kernel with kexec-tools into 2071 a specially reserved region and then later executed after 2072 a crash by kdump/kexec. The crash dump kernel must be compiled 2073 to a memory address not used by the main kernel or BIOS using 2074 PHYSICAL_START, or it must be built as a relocatable image 2075 (CONFIG_RELOCATABLE=y). 2076 For more details see Documentation/admin-guide/kdump/kdump.rst 2077 2078config KEXEC_JUMP 2079 bool "kexec jump" 2080 depends on KEXEC && HIBERNATION 2081 ---help--- 2082 Jump between original kernel and kexeced kernel and invoke 2083 code in physical address mode via KEXEC 2084 2085config PHYSICAL_START 2086 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2087 default "0x1000000" 2088 ---help--- 2089 This gives the physical address where the kernel is loaded. 2090 2091 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2092 bzImage will decompress itself to above physical address and 2093 run from there. Otherwise, bzImage will run from the address where 2094 it has been loaded by the boot loader and will ignore above physical 2095 address. 2096 2097 In normal kdump cases one does not have to set/change this option 2098 as now bzImage can be compiled as a completely relocatable image 2099 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2100 address. This option is mainly useful for the folks who don't want 2101 to use a bzImage for capturing the crash dump and want to use a 2102 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2103 to be specifically compiled to run from a specific memory area 2104 (normally a reserved region) and this option comes handy. 2105 2106 So if you are using bzImage for capturing the crash dump, 2107 leave the value here unchanged to 0x1000000 and set 2108 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2109 for capturing the crash dump change this value to start of 2110 the reserved region. In other words, it can be set based on 2111 the "X" value as specified in the "crashkernel=YM@XM" 2112 command line boot parameter passed to the panic-ed 2113 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2114 for more details about crash dumps. 2115 2116 Usage of bzImage for capturing the crash dump is recommended as 2117 one does not have to build two kernels. Same kernel can be used 2118 as production kernel and capture kernel. Above option should have 2119 gone away after relocatable bzImage support is introduced. But it 2120 is present because there are users out there who continue to use 2121 vmlinux for dump capture. This option should go away down the 2122 line. 2123 2124 Don't change this unless you know what you are doing. 2125 2126config RELOCATABLE 2127 bool "Build a relocatable kernel" 2128 default y 2129 ---help--- 2130 This builds a kernel image that retains relocation information 2131 so it can be loaded someplace besides the default 1MB. 2132 The relocations tend to make the kernel binary about 10% larger, 2133 but are discarded at runtime. 2134 2135 One use is for the kexec on panic case where the recovery kernel 2136 must live at a different physical address than the primary 2137 kernel. 2138 2139 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2140 it has been loaded at and the compile time physical address 2141 (CONFIG_PHYSICAL_START) is used as the minimum location. 2142 2143config RANDOMIZE_BASE 2144 bool "Randomize the address of the kernel image (KASLR)" 2145 depends on RELOCATABLE 2146 default y 2147 ---help--- 2148 In support of Kernel Address Space Layout Randomization (KASLR), 2149 this randomizes the physical address at which the kernel image 2150 is decompressed and the virtual address where the kernel 2151 image is mapped, as a security feature that deters exploit 2152 attempts relying on knowledge of the location of kernel 2153 code internals. 2154 2155 On 64-bit, the kernel physical and virtual addresses are 2156 randomized separately. The physical address will be anywhere 2157 between 16MB and the top of physical memory (up to 64TB). The 2158 virtual address will be randomized from 16MB up to 1GB (9 bits 2159 of entropy). Note that this also reduces the memory space 2160 available to kernel modules from 1.5GB to 1GB. 2161 2162 On 32-bit, the kernel physical and virtual addresses are 2163 randomized together. They will be randomized from 16MB up to 2164 512MB (8 bits of entropy). 2165 2166 Entropy is generated using the RDRAND instruction if it is 2167 supported. If RDTSC is supported, its value is mixed into 2168 the entropy pool as well. If neither RDRAND nor RDTSC are 2169 supported, then entropy is read from the i8254 timer. The 2170 usable entropy is limited by the kernel being built using 2171 2GB addressing, and that PHYSICAL_ALIGN must be at a 2172 minimum of 2MB. As a result, only 10 bits of entropy are 2173 theoretically possible, but the implementations are further 2174 limited due to memory layouts. 2175 2176 If unsure, say Y. 2177 2178# Relocation on x86 needs some additional build support 2179config X86_NEED_RELOCS 2180 def_bool y 2181 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2182 2183config PHYSICAL_ALIGN 2184 hex "Alignment value to which kernel should be aligned" 2185 default "0x200000" 2186 range 0x2000 0x1000000 if X86_32 2187 range 0x200000 0x1000000 if X86_64 2188 ---help--- 2189 This value puts the alignment restrictions on physical address 2190 where kernel is loaded and run from. Kernel is compiled for an 2191 address which meets above alignment restriction. 2192 2193 If bootloader loads the kernel at a non-aligned address and 2194 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2195 address aligned to above value and run from there. 2196 2197 If bootloader loads the kernel at a non-aligned address and 2198 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2199 load address and decompress itself to the address it has been 2200 compiled for and run from there. The address for which kernel is 2201 compiled already meets above alignment restrictions. Hence the 2202 end result is that kernel runs from a physical address meeting 2203 above alignment restrictions. 2204 2205 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2206 this value must be a multiple of 0x200000. 2207 2208 Don't change this unless you know what you are doing. 2209 2210config DYNAMIC_MEMORY_LAYOUT 2211 bool 2212 ---help--- 2213 This option makes base addresses of vmalloc and vmemmap as well as 2214 __PAGE_OFFSET movable during boot. 2215 2216config RANDOMIZE_MEMORY 2217 bool "Randomize the kernel memory sections" 2218 depends on X86_64 2219 depends on RANDOMIZE_BASE 2220 select DYNAMIC_MEMORY_LAYOUT 2221 default RANDOMIZE_BASE 2222 ---help--- 2223 Randomizes the base virtual address of kernel memory sections 2224 (physical memory mapping, vmalloc & vmemmap). This security feature 2225 makes exploits relying on predictable memory locations less reliable. 2226 2227 The order of allocations remains unchanged. Entropy is generated in 2228 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2229 configuration have in average 30,000 different possible virtual 2230 addresses for each memory section. 2231 2232 If unsure, say Y. 2233 2234config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2235 hex "Physical memory mapping padding" if EXPERT 2236 depends on RANDOMIZE_MEMORY 2237 default "0xa" if MEMORY_HOTPLUG 2238 default "0x0" 2239 range 0x1 0x40 if MEMORY_HOTPLUG 2240 range 0x0 0x40 2241 ---help--- 2242 Define the padding in terabytes added to the existing physical 2243 memory size during kernel memory randomization. It is useful 2244 for memory hotplug support but reduces the entropy available for 2245 address randomization. 2246 2247 If unsure, leave at the default value. 2248 2249config HOTPLUG_CPU 2250 def_bool y 2251 depends on SMP 2252 2253config BOOTPARAM_HOTPLUG_CPU0 2254 bool "Set default setting of cpu0_hotpluggable" 2255 depends on HOTPLUG_CPU 2256 ---help--- 2257 Set whether default state of cpu0_hotpluggable is on or off. 2258 2259 Say Y here to enable CPU0 hotplug by default. If this switch 2260 is turned on, there is no need to give cpu0_hotplug kernel 2261 parameter and the CPU0 hotplug feature is enabled by default. 2262 2263 Please note: there are two known CPU0 dependencies if you want 2264 to enable the CPU0 hotplug feature either by this switch or by 2265 cpu0_hotplug kernel parameter. 2266 2267 First, resume from hibernate or suspend always starts from CPU0. 2268 So hibernate and suspend are prevented if CPU0 is offline. 2269 2270 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2271 offline if any interrupt can not migrate out of CPU0. There may 2272 be other CPU0 dependencies. 2273 2274 Please make sure the dependencies are under your control before 2275 you enable this feature. 2276 2277 Say N if you don't want to enable CPU0 hotplug feature by default. 2278 You still can enable the CPU0 hotplug feature at boot by kernel 2279 parameter cpu0_hotplug. 2280 2281config DEBUG_HOTPLUG_CPU0 2282 def_bool n 2283 prompt "Debug CPU0 hotplug" 2284 depends on HOTPLUG_CPU 2285 ---help--- 2286 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2287 soon as possible and boots up userspace with CPU0 offlined. User 2288 can online CPU0 back after boot time. 2289 2290 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2291 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2292 compilation or giving cpu0_hotplug kernel parameter at boot. 2293 2294 If unsure, say N. 2295 2296config COMPAT_VDSO 2297 def_bool n 2298 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2299 depends on COMPAT_32 2300 ---help--- 2301 Certain buggy versions of glibc will crash if they are 2302 presented with a 32-bit vDSO that is not mapped at the address 2303 indicated in its segment table. 2304 2305 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2306 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2307 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2308 the only released version with the bug, but OpenSUSE 9 2309 contains a buggy "glibc 2.3.2". 2310 2311 The symptom of the bug is that everything crashes on startup, saying: 2312 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2313 2314 Saying Y here changes the default value of the vdso32 boot 2315 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2316 This works around the glibc bug but hurts performance. 2317 2318 If unsure, say N: if you are compiling your own kernel, you 2319 are unlikely to be using a buggy version of glibc. 2320 2321choice 2322 prompt "vsyscall table for legacy applications" 2323 depends on X86_64 2324 default LEGACY_VSYSCALL_XONLY 2325 help 2326 Legacy user code that does not know how to find the vDSO expects 2327 to be able to issue three syscalls by calling fixed addresses in 2328 kernel space. Since this location is not randomized with ASLR, 2329 it can be used to assist security vulnerability exploitation. 2330 2331 This setting can be changed at boot time via the kernel command 2332 line parameter vsyscall=[emulate|xonly|none]. 2333 2334 On a system with recent enough glibc (2.14 or newer) and no 2335 static binaries, you can say None without a performance penalty 2336 to improve security. 2337 2338 If unsure, select "Emulate execution only". 2339 2340 config LEGACY_VSYSCALL_EMULATE 2341 bool "Full emulation" 2342 help 2343 The kernel traps and emulates calls into the fixed vsyscall 2344 address mapping. This makes the mapping non-executable, but 2345 it still contains readable known contents, which could be 2346 used in certain rare security vulnerability exploits. This 2347 configuration is recommended when using legacy userspace 2348 that still uses vsyscalls along with legacy binary 2349 instrumentation tools that require code to be readable. 2350 2351 An example of this type of legacy userspace is running 2352 Pin on an old binary that still uses vsyscalls. 2353 2354 config LEGACY_VSYSCALL_XONLY 2355 bool "Emulate execution only" 2356 help 2357 The kernel traps and emulates calls into the fixed vsyscall 2358 address mapping and does not allow reads. This 2359 configuration is recommended when userspace might use the 2360 legacy vsyscall area but support for legacy binary 2361 instrumentation of legacy code is not needed. It mitigates 2362 certain uses of the vsyscall area as an ASLR-bypassing 2363 buffer. 2364 2365 config LEGACY_VSYSCALL_NONE 2366 bool "None" 2367 help 2368 There will be no vsyscall mapping at all. This will 2369 eliminate any risk of ASLR bypass due to the vsyscall 2370 fixed address mapping. Attempts to use the vsyscalls 2371 will be reported to dmesg, so that either old or 2372 malicious userspace programs can be identified. 2373 2374endchoice 2375 2376config CMDLINE_BOOL 2377 bool "Built-in kernel command line" 2378 ---help--- 2379 Allow for specifying boot arguments to the kernel at 2380 build time. On some systems (e.g. embedded ones), it is 2381 necessary or convenient to provide some or all of the 2382 kernel boot arguments with the kernel itself (that is, 2383 to not rely on the boot loader to provide them.) 2384 2385 To compile command line arguments into the kernel, 2386 set this option to 'Y', then fill in the 2387 boot arguments in CONFIG_CMDLINE. 2388 2389 Systems with fully functional boot loaders (i.e. non-embedded) 2390 should leave this option set to 'N'. 2391 2392config CMDLINE 2393 string "Built-in kernel command string" 2394 depends on CMDLINE_BOOL 2395 default "" 2396 ---help--- 2397 Enter arguments here that should be compiled into the kernel 2398 image and used at boot time. If the boot loader provides a 2399 command line at boot time, it is appended to this string to 2400 form the full kernel command line, when the system boots. 2401 2402 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2403 change this behavior. 2404 2405 In most cases, the command line (whether built-in or provided 2406 by the boot loader) should specify the device for the root 2407 file system. 2408 2409config CMDLINE_OVERRIDE 2410 bool "Built-in command line overrides boot loader arguments" 2411 depends on CMDLINE_BOOL && CMDLINE != "" 2412 ---help--- 2413 Set this option to 'Y' to have the kernel ignore the boot loader 2414 command line, and use ONLY the built-in command line. 2415 2416 This is used to work around broken boot loaders. This should 2417 be set to 'N' under normal conditions. 2418 2419config MODIFY_LDT_SYSCALL 2420 bool "Enable the LDT (local descriptor table)" if EXPERT 2421 default y 2422 ---help--- 2423 Linux can allow user programs to install a per-process x86 2424 Local Descriptor Table (LDT) using the modify_ldt(2) system 2425 call. This is required to run 16-bit or segmented code such as 2426 DOSEMU or some Wine programs. It is also used by some very old 2427 threading libraries. 2428 2429 Enabling this feature adds a small amount of overhead to 2430 context switches and increases the low-level kernel attack 2431 surface. Disabling it removes the modify_ldt(2) system call. 2432 2433 Saying 'N' here may make sense for embedded or server kernels. 2434 2435source "kernel/livepatch/Kconfig" 2436 2437endmenu 2438 2439config ARCH_HAS_ADD_PAGES 2440 def_bool y 2441 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2442 2443config ARCH_ENABLE_MEMORY_HOTPLUG 2444 def_bool y 2445 depends on X86_64 || (X86_32 && HIGHMEM) 2446 2447config ARCH_ENABLE_MEMORY_HOTREMOVE 2448 def_bool y 2449 depends on MEMORY_HOTPLUG 2450 2451config USE_PERCPU_NUMA_NODE_ID 2452 def_bool y 2453 depends on NUMA 2454 2455config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2456 def_bool y 2457 depends on X86_64 || X86_PAE 2458 2459config ARCH_ENABLE_HUGEPAGE_MIGRATION 2460 def_bool y 2461 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2462 2463config ARCH_ENABLE_THP_MIGRATION 2464 def_bool y 2465 depends on X86_64 && TRANSPARENT_HUGEPAGE 2466 2467menu "Power management and ACPI options" 2468 2469config ARCH_HIBERNATION_HEADER 2470 def_bool y 2471 depends on HIBERNATION 2472 2473source "kernel/power/Kconfig" 2474 2475source "drivers/acpi/Kconfig" 2476 2477source "drivers/sfi/Kconfig" 2478 2479config X86_APM_BOOT 2480 def_bool y 2481 depends on APM 2482 2483menuconfig APM 2484 tristate "APM (Advanced Power Management) BIOS support" 2485 depends on X86_32 && PM_SLEEP 2486 ---help--- 2487 APM is a BIOS specification for saving power using several different 2488 techniques. This is mostly useful for battery powered laptops with 2489 APM compliant BIOSes. If you say Y here, the system time will be 2490 reset after a RESUME operation, the /proc/apm device will provide 2491 battery status information, and user-space programs will receive 2492 notification of APM "events" (e.g. battery status change). 2493 2494 If you select "Y" here, you can disable actual use of the APM 2495 BIOS by passing the "apm=off" option to the kernel at boot time. 2496 2497 Note that the APM support is almost completely disabled for 2498 machines with more than one CPU. 2499 2500 In order to use APM, you will need supporting software. For location 2501 and more information, read <file:Documentation/power/apm-acpi.rst> 2502 and the Battery Powered Linux mini-HOWTO, available from 2503 <http://www.tldp.org/docs.html#howto>. 2504 2505 This driver does not spin down disk drives (see the hdparm(8) 2506 manpage ("man 8 hdparm") for that), and it doesn't turn off 2507 VESA-compliant "green" monitors. 2508 2509 This driver does not support the TI 4000M TravelMate and the ACER 2510 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2511 desktop machines also don't have compliant BIOSes, and this driver 2512 may cause those machines to panic during the boot phase. 2513 2514 Generally, if you don't have a battery in your machine, there isn't 2515 much point in using this driver and you should say N. If you get 2516 random kernel OOPSes or reboots that don't seem to be related to 2517 anything, try disabling/enabling this option (or disabling/enabling 2518 APM in your BIOS). 2519 2520 Some other things you should try when experiencing seemingly random, 2521 "weird" problems: 2522 2523 1) make sure that you have enough swap space and that it is 2524 enabled. 2525 2) pass the "no-hlt" option to the kernel 2526 3) switch on floating point emulation in the kernel and pass 2527 the "no387" option to the kernel 2528 4) pass the "floppy=nodma" option to the kernel 2529 5) pass the "mem=4M" option to the kernel (thereby disabling 2530 all but the first 4 MB of RAM) 2531 6) make sure that the CPU is not over clocked. 2532 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2533 8) disable the cache from your BIOS settings 2534 9) install a fan for the video card or exchange video RAM 2535 10) install a better fan for the CPU 2536 11) exchange RAM chips 2537 12) exchange the motherboard. 2538 2539 To compile this driver as a module, choose M here: the 2540 module will be called apm. 2541 2542if APM 2543 2544config APM_IGNORE_USER_SUSPEND 2545 bool "Ignore USER SUSPEND" 2546 ---help--- 2547 This option will ignore USER SUSPEND requests. On machines with a 2548 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2549 series notebooks, it is necessary to say Y because of a BIOS bug. 2550 2551config APM_DO_ENABLE 2552 bool "Enable PM at boot time" 2553 ---help--- 2554 Enable APM features at boot time. From page 36 of the APM BIOS 2555 specification: "When disabled, the APM BIOS does not automatically 2556 power manage devices, enter the Standby State, enter the Suspend 2557 State, or take power saving steps in response to CPU Idle calls." 2558 This driver will make CPU Idle calls when Linux is idle (unless this 2559 feature is turned off -- see "Do CPU IDLE calls", below). This 2560 should always save battery power, but more complicated APM features 2561 will be dependent on your BIOS implementation. You may need to turn 2562 this option off if your computer hangs at boot time when using APM 2563 support, or if it beeps continuously instead of suspending. Turn 2564 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2565 T400CDT. This is off by default since most machines do fine without 2566 this feature. 2567 2568config APM_CPU_IDLE 2569 depends on CPU_IDLE 2570 bool "Make CPU Idle calls when idle" 2571 ---help--- 2572 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2573 On some machines, this can activate improved power savings, such as 2574 a slowed CPU clock rate, when the machine is idle. These idle calls 2575 are made after the idle loop has run for some length of time (e.g., 2576 333 mS). On some machines, this will cause a hang at boot time or 2577 whenever the CPU becomes idle. (On machines with more than one CPU, 2578 this option does nothing.) 2579 2580config APM_DISPLAY_BLANK 2581 bool "Enable console blanking using APM" 2582 ---help--- 2583 Enable console blanking using the APM. Some laptops can use this to 2584 turn off the LCD backlight when the screen blanker of the Linux 2585 virtual console blanks the screen. Note that this is only used by 2586 the virtual console screen blanker, and won't turn off the backlight 2587 when using the X Window system. This also doesn't have anything to 2588 do with your VESA-compliant power-saving monitor. Further, this 2589 option doesn't work for all laptops -- it might not turn off your 2590 backlight at all, or it might print a lot of errors to the console, 2591 especially if you are using gpm. 2592 2593config APM_ALLOW_INTS 2594 bool "Allow interrupts during APM BIOS calls" 2595 ---help--- 2596 Normally we disable external interrupts while we are making calls to 2597 the APM BIOS as a measure to lessen the effects of a badly behaving 2598 BIOS implementation. The BIOS should reenable interrupts if it 2599 needs to. Unfortunately, some BIOSes do not -- especially those in 2600 many of the newer IBM Thinkpads. If you experience hangs when you 2601 suspend, try setting this to Y. Otherwise, say N. 2602 2603endif # APM 2604 2605source "drivers/cpufreq/Kconfig" 2606 2607source "drivers/cpuidle/Kconfig" 2608 2609source "drivers/idle/Kconfig" 2610 2611endmenu 2612 2613 2614menu "Bus options (PCI etc.)" 2615 2616choice 2617 prompt "PCI access mode" 2618 depends on X86_32 && PCI 2619 default PCI_GOANY 2620 ---help--- 2621 On PCI systems, the BIOS can be used to detect the PCI devices and 2622 determine their configuration. However, some old PCI motherboards 2623 have BIOS bugs and may crash if this is done. Also, some embedded 2624 PCI-based systems don't have any BIOS at all. Linux can also try to 2625 detect the PCI hardware directly without using the BIOS. 2626 2627 With this option, you can specify how Linux should detect the 2628 PCI devices. If you choose "BIOS", the BIOS will be used, 2629 if you choose "Direct", the BIOS won't be used, and if you 2630 choose "MMConfig", then PCI Express MMCONFIG will be used. 2631 If you choose "Any", the kernel will try MMCONFIG, then the 2632 direct access method and falls back to the BIOS if that doesn't 2633 work. If unsure, go with the default, which is "Any". 2634 2635config PCI_GOBIOS 2636 bool "BIOS" 2637 2638config PCI_GOMMCONFIG 2639 bool "MMConfig" 2640 2641config PCI_GODIRECT 2642 bool "Direct" 2643 2644config PCI_GOOLPC 2645 bool "OLPC XO-1" 2646 depends on OLPC 2647 2648config PCI_GOANY 2649 bool "Any" 2650 2651endchoice 2652 2653config PCI_BIOS 2654 def_bool y 2655 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2656 2657# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2658config PCI_DIRECT 2659 def_bool y 2660 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2661 2662config PCI_MMCONFIG 2663 bool "Support mmconfig PCI config space access" if X86_64 2664 default y 2665 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2666 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2667 2668config PCI_OLPC 2669 def_bool y 2670 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2671 2672config PCI_XEN 2673 def_bool y 2674 depends on PCI && XEN 2675 select SWIOTLB_XEN 2676 2677config MMCONF_FAM10H 2678 def_bool y 2679 depends on X86_64 && PCI_MMCONFIG && ACPI 2680 2681config PCI_CNB20LE_QUIRK 2682 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2683 depends on PCI 2684 help 2685 Read the PCI windows out of the CNB20LE host bridge. This allows 2686 PCI hotplug to work on systems with the CNB20LE chipset which do 2687 not have ACPI. 2688 2689 There's no public spec for this chipset, and this functionality 2690 is known to be incomplete. 2691 2692 You should say N unless you know you need this. 2693 2694config ISA_BUS 2695 bool "ISA bus support on modern systems" if EXPERT 2696 help 2697 Expose ISA bus device drivers and options available for selection and 2698 configuration. Enable this option if your target machine has an ISA 2699 bus. ISA is an older system, displaced by PCI and newer bus 2700 architectures -- if your target machine is modern, it probably does 2701 not have an ISA bus. 2702 2703 If unsure, say N. 2704 2705# x86_64 have no ISA slots, but can have ISA-style DMA. 2706config ISA_DMA_API 2707 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2708 default y 2709 help 2710 Enables ISA-style DMA support for devices requiring such controllers. 2711 If unsure, say Y. 2712 2713if X86_32 2714 2715config ISA 2716 bool "ISA support" 2717 ---help--- 2718 Find out whether you have ISA slots on your motherboard. ISA is the 2719 name of a bus system, i.e. the way the CPU talks to the other stuff 2720 inside your box. Other bus systems are PCI, EISA, MicroChannel 2721 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2722 newer boards don't support it. If you have ISA, say Y, otherwise N. 2723 2724config SCx200 2725 tristate "NatSemi SCx200 support" 2726 ---help--- 2727 This provides basic support for National Semiconductor's 2728 (now AMD's) Geode processors. The driver probes for the 2729 PCI-IDs of several on-chip devices, so its a good dependency 2730 for other scx200_* drivers. 2731 2732 If compiled as a module, the driver is named scx200. 2733 2734config SCx200HR_TIMER 2735 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2736 depends on SCx200 2737 default y 2738 ---help--- 2739 This driver provides a clocksource built upon the on-chip 2740 27MHz high-resolution timer. Its also a workaround for 2741 NSC Geode SC-1100's buggy TSC, which loses time when the 2742 processor goes idle (as is done by the scheduler). The 2743 other workaround is idle=poll boot option. 2744 2745config OLPC 2746 bool "One Laptop Per Child support" 2747 depends on !X86_PAE 2748 select GPIOLIB 2749 select OF 2750 select OF_PROMTREE 2751 select IRQ_DOMAIN 2752 select OLPC_EC 2753 ---help--- 2754 Add support for detecting the unique features of the OLPC 2755 XO hardware. 2756 2757config OLPC_XO1_PM 2758 bool "OLPC XO-1 Power Management" 2759 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2760 ---help--- 2761 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2762 2763config OLPC_XO1_RTC 2764 bool "OLPC XO-1 Real Time Clock" 2765 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2766 ---help--- 2767 Add support for the XO-1 real time clock, which can be used as a 2768 programmable wakeup source. 2769 2770config OLPC_XO1_SCI 2771 bool "OLPC XO-1 SCI extras" 2772 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2773 depends on INPUT=y 2774 select POWER_SUPPLY 2775 ---help--- 2776 Add support for SCI-based features of the OLPC XO-1 laptop: 2777 - EC-driven system wakeups 2778 - Power button 2779 - Ebook switch 2780 - Lid switch 2781 - AC adapter status updates 2782 - Battery status updates 2783 2784config OLPC_XO15_SCI 2785 bool "OLPC XO-1.5 SCI extras" 2786 depends on OLPC && ACPI 2787 select POWER_SUPPLY 2788 ---help--- 2789 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2790 - EC-driven system wakeups 2791 - AC adapter status updates 2792 - Battery status updates 2793 2794config ALIX 2795 bool "PCEngines ALIX System Support (LED setup)" 2796 select GPIOLIB 2797 ---help--- 2798 This option enables system support for the PCEngines ALIX. 2799 At present this just sets up LEDs for GPIO control on 2800 ALIX2/3/6 boards. However, other system specific setup should 2801 get added here. 2802 2803 Note: You must still enable the drivers for GPIO and LED support 2804 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2805 2806 Note: You have to set alix.force=1 for boards with Award BIOS. 2807 2808config NET5501 2809 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2810 select GPIOLIB 2811 ---help--- 2812 This option enables system support for the Soekris Engineering net5501. 2813 2814config GEOS 2815 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2816 select GPIOLIB 2817 depends on DMI 2818 ---help--- 2819 This option enables system support for the Traverse Technologies GEOS. 2820 2821config TS5500 2822 bool "Technologic Systems TS-5500 platform support" 2823 depends on MELAN 2824 select CHECK_SIGNATURE 2825 select NEW_LEDS 2826 select LEDS_CLASS 2827 ---help--- 2828 This option enables system support for the Technologic Systems TS-5500. 2829 2830endif # X86_32 2831 2832config AMD_NB 2833 def_bool y 2834 depends on CPU_SUP_AMD && PCI 2835 2836config X86_SYSFB 2837 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2838 help 2839 Firmwares often provide initial graphics framebuffers so the BIOS, 2840 bootloader or kernel can show basic video-output during boot for 2841 user-guidance and debugging. Historically, x86 used the VESA BIOS 2842 Extensions and EFI-framebuffers for this, which are mostly limited 2843 to x86. 2844 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2845 framebuffers so the new generic system-framebuffer drivers can be 2846 used on x86. If the framebuffer is not compatible with the generic 2847 modes, it is advertised as fallback platform framebuffer so legacy 2848 drivers like efifb, vesafb and uvesafb can pick it up. 2849 If this option is not selected, all system framebuffers are always 2850 marked as fallback platform framebuffers as usual. 2851 2852 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2853 not be able to pick up generic system framebuffers if this option 2854 is selected. You are highly encouraged to enable simplefb as 2855 replacement if you select this option. simplefb can correctly deal 2856 with generic system framebuffers. But you should still keep vesafb 2857 and others enabled as fallback if a system framebuffer is 2858 incompatible with simplefb. 2859 2860 If unsure, say Y. 2861 2862endmenu 2863 2864 2865menu "Binary Emulations" 2866 2867config IA32_EMULATION 2868 bool "IA32 Emulation" 2869 depends on X86_64 2870 select ARCH_WANT_OLD_COMPAT_IPC 2871 select BINFMT_ELF 2872 select COMPAT_BINFMT_ELF 2873 select COMPAT_OLD_SIGACTION 2874 ---help--- 2875 Include code to run legacy 32-bit programs under a 2876 64-bit kernel. You should likely turn this on, unless you're 2877 100% sure that you don't have any 32-bit programs left. 2878 2879config IA32_AOUT 2880 tristate "IA32 a.out support" 2881 depends on IA32_EMULATION 2882 depends on BROKEN 2883 ---help--- 2884 Support old a.out binaries in the 32bit emulation. 2885 2886config X86_X32 2887 bool "x32 ABI for 64-bit mode" 2888 depends on X86_64 2889 ---help--- 2890 Include code to run binaries for the x32 native 32-bit ABI 2891 for 64-bit processors. An x32 process gets access to the 2892 full 64-bit register file and wide data path while leaving 2893 pointers at 32 bits for smaller memory footprint. 2894 2895 You will need a recent binutils (2.22 or later) with 2896 elf32_x86_64 support enabled to compile a kernel with this 2897 option set. 2898 2899config COMPAT_32 2900 def_bool y 2901 depends on IA32_EMULATION || X86_32 2902 select HAVE_UID16 2903 select OLD_SIGSUSPEND3 2904 2905config COMPAT 2906 def_bool y 2907 depends on IA32_EMULATION || X86_X32 2908 2909if COMPAT 2910config COMPAT_FOR_U64_ALIGNMENT 2911 def_bool y 2912 2913config SYSVIPC_COMPAT 2914 def_bool y 2915 depends on SYSVIPC 2916endif 2917 2918endmenu 2919 2920 2921config HAVE_ATOMIC_IOMAP 2922 def_bool y 2923 depends on X86_32 2924 2925source "drivers/firmware/Kconfig" 2926 2927source "arch/x86/kvm/Kconfig" 2928 2929source "arch/x86/Kconfig.assembler" 2930