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_DEBUG_VM_PGTABLE if !X86_PAE 63 select ARCH_HAS_DEVMEM_IS_ALLOWED 64 select ARCH_HAS_EARLY_DEBUG if KGDB 65 select ARCH_HAS_ELF_RANDOMIZE 66 select ARCH_HAS_FAST_MULTIPLIER 67 select ARCH_HAS_FILTER_PGPROT 68 select ARCH_HAS_FORTIFY_SOURCE 69 select ARCH_HAS_GCOV_PROFILE_ALL 70 select ARCH_HAS_KCOV if X86_64 71 select ARCH_HAS_MEM_ENCRYPT 72 select ARCH_HAS_MEMBARRIER_SYNC_CORE 73 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 74 select ARCH_HAS_PMEM_API if X86_64 75 select ARCH_HAS_PTE_DEVMAP if X86_64 76 select ARCH_HAS_PTE_SPECIAL 77 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 78 select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE 79 select ARCH_HAS_SET_MEMORY 80 select ARCH_HAS_SET_DIRECT_MAP 81 select ARCH_HAS_STRICT_KERNEL_RWX 82 select ARCH_HAS_STRICT_MODULE_RWX 83 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 84 select ARCH_HAS_SYSCALL_WRAPPER 85 select ARCH_HAS_UBSAN_SANITIZE_ALL 86 select ARCH_HAS_DEBUG_WX 87 select ARCH_HAVE_NMI_SAFE_CMPXCHG 88 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 89 select ARCH_MIGHT_HAVE_PC_PARPORT 90 select ARCH_MIGHT_HAVE_PC_SERIO 91 select ARCH_STACKWALK 92 select ARCH_SUPPORTS_ACPI 93 select ARCH_SUPPORTS_ATOMIC_RMW 94 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 95 select ARCH_USE_BUILTIN_BSWAP 96 select ARCH_USE_QUEUED_RWLOCKS 97 select ARCH_USE_QUEUED_SPINLOCKS 98 select ARCH_USE_SYM_ANNOTATIONS 99 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 100 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 101 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 102 select ARCH_WANT_HUGE_PMD_SHARE 103 select ARCH_WANTS_THP_SWAP if X86_64 104 select BUILDTIME_TABLE_SORT 105 select CLKEVT_I8253 106 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 107 select CLOCKSOURCE_WATCHDOG 108 select DCACHE_WORD_ACCESS 109 select EDAC_ATOMIC_SCRUB 110 select EDAC_SUPPORT 111 select GENERIC_CLOCKEVENTS 112 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 113 select GENERIC_CLOCKEVENTS_MIN_ADJUST 114 select GENERIC_CMOS_UPDATE 115 select GENERIC_CPU_AUTOPROBE 116 select GENERIC_CPU_VULNERABILITIES 117 select GENERIC_EARLY_IOREMAP 118 select GENERIC_FIND_FIRST_BIT 119 select GENERIC_IOMAP 120 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 121 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 122 select GENERIC_IRQ_MIGRATION if SMP 123 select GENERIC_IRQ_PROBE 124 select GENERIC_IRQ_RESERVATION_MODE 125 select GENERIC_IRQ_SHOW 126 select GENERIC_PENDING_IRQ if SMP 127 select GENERIC_PTDUMP 128 select GENERIC_SMP_IDLE_THREAD 129 select GENERIC_STRNCPY_FROM_USER 130 select GENERIC_STRNLEN_USER 131 select GENERIC_TIME_VSYSCALL 132 select GENERIC_GETTIMEOFDAY 133 select GENERIC_VDSO_TIME_NS 134 select GUP_GET_PTE_LOW_HIGH if X86_PAE 135 select HARDIRQS_SW_RESEND 136 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 137 select HAVE_ACPI_APEI if ACPI 138 select HAVE_ACPI_APEI_NMI if ACPI 139 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 140 select HAVE_ARCH_AUDITSYSCALL 141 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 142 select HAVE_ARCH_JUMP_LABEL 143 select HAVE_ARCH_JUMP_LABEL_RELATIVE 144 select HAVE_ARCH_KASAN if X86_64 145 select HAVE_ARCH_KASAN_VMALLOC if X86_64 146 select HAVE_ARCH_KGDB 147 select HAVE_ARCH_MMAP_RND_BITS if MMU 148 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 149 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 150 select HAVE_ARCH_PREL32_RELOCATIONS 151 select HAVE_ARCH_SECCOMP_FILTER 152 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 153 select HAVE_ARCH_STACKLEAK 154 select HAVE_ARCH_TRACEHOOK 155 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 156 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 157 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 158 select HAVE_ARCH_VMAP_STACK if X86_64 159 select HAVE_ARCH_WITHIN_STACK_FRAMES 160 select HAVE_ASM_MODVERSIONS 161 select HAVE_CMPXCHG_DOUBLE 162 select HAVE_CMPXCHG_LOCAL 163 select HAVE_CONTEXT_TRACKING if X86_64 164 select HAVE_COPY_THREAD_TLS 165 select HAVE_C_RECORDMCOUNT 166 select HAVE_DEBUG_KMEMLEAK 167 select HAVE_DMA_CONTIGUOUS 168 select HAVE_DYNAMIC_FTRACE 169 select HAVE_DYNAMIC_FTRACE_WITH_REGS 170 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 171 select HAVE_EBPF_JIT 172 select HAVE_EFFICIENT_UNALIGNED_ACCESS 173 select HAVE_EISA 174 select HAVE_EXIT_THREAD 175 select HAVE_FAST_GUP 176 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 177 select HAVE_FTRACE_MCOUNT_RECORD 178 select HAVE_FUNCTION_GRAPH_TRACER 179 select HAVE_FUNCTION_TRACER 180 select HAVE_GCC_PLUGINS 181 select HAVE_HW_BREAKPOINT 182 select HAVE_IDE 183 select HAVE_IOREMAP_PROT 184 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 185 select HAVE_IRQ_TIME_ACCOUNTING 186 select HAVE_KERNEL_BZIP2 187 select HAVE_KERNEL_GZIP 188 select HAVE_KERNEL_LZ4 189 select HAVE_KERNEL_LZMA 190 select HAVE_KERNEL_LZO 191 select HAVE_KERNEL_XZ 192 select HAVE_KPROBES 193 select HAVE_KPROBES_ON_FTRACE 194 select HAVE_FUNCTION_ERROR_INJECTION 195 select HAVE_KRETPROBES 196 select HAVE_KVM 197 select HAVE_LIVEPATCH if X86_64 198 select HAVE_MIXED_BREAKPOINTS_REGS 199 select HAVE_MOD_ARCH_SPECIFIC 200 select HAVE_MOVE_PMD 201 select HAVE_NMI 202 select HAVE_OPROFILE 203 select HAVE_OPTPROBES 204 select HAVE_PCSPKR_PLATFORM 205 select HAVE_PERF_EVENTS 206 select HAVE_PERF_EVENTS_NMI 207 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 208 select HAVE_PCI 209 select HAVE_PERF_REGS 210 select HAVE_PERF_USER_STACK_DUMP 211 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 212 select HAVE_REGS_AND_STACK_ACCESS_API 213 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 214 select HAVE_FUNCTION_ARG_ACCESS_API 215 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 216 select HAVE_STACK_VALIDATION if X86_64 217 select HAVE_RSEQ 218 select HAVE_SYSCALL_TRACEPOINTS 219 select HAVE_UNSTABLE_SCHED_CLOCK 220 select HAVE_USER_RETURN_NOTIFIER 221 select HAVE_GENERIC_VDSO 222 select HOTPLUG_SMT if SMP 223 select IRQ_FORCED_THREADING 224 select NEED_SG_DMA_LENGTH 225 select PCI_DOMAINS if PCI 226 select PCI_LOCKLESS_CONFIG if PCI 227 select PERF_EVENTS 228 select RTC_LIB 229 select RTC_MC146818_LIB 230 select SPARSE_IRQ 231 select SRCU 232 select SYSCTL_EXCEPTION_TRACE 233 select THREAD_INFO_IN_TASK 234 select USER_STACKTRACE_SUPPORT 235 select VIRT_TO_BUS 236 select HAVE_ARCH_KCSAN if X86_64 237 select X86_FEATURE_NAMES if PROC_FS 238 select PROC_PID_ARCH_STATUS if PROC_FS 239 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 240 241config INSTRUCTION_DECODER 242 def_bool y 243 depends on KPROBES || PERF_EVENTS || UPROBES 244 245config OUTPUT_FORMAT 246 string 247 default "elf32-i386" if X86_32 248 default "elf64-x86-64" if X86_64 249 250config LOCKDEP_SUPPORT 251 def_bool y 252 253config STACKTRACE_SUPPORT 254 def_bool y 255 256config MMU 257 def_bool y 258 259config ARCH_MMAP_RND_BITS_MIN 260 default 28 if 64BIT 261 default 8 262 263config ARCH_MMAP_RND_BITS_MAX 264 default 32 if 64BIT 265 default 16 266 267config ARCH_MMAP_RND_COMPAT_BITS_MIN 268 default 8 269 270config ARCH_MMAP_RND_COMPAT_BITS_MAX 271 default 16 272 273config SBUS 274 bool 275 276config GENERIC_ISA_DMA 277 def_bool y 278 depends on ISA_DMA_API 279 280config GENERIC_BUG 281 def_bool y 282 depends on BUG 283 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 284 285config GENERIC_BUG_RELATIVE_POINTERS 286 bool 287 288config ARCH_MAY_HAVE_PC_FDC 289 def_bool y 290 depends on ISA_DMA_API 291 292config GENERIC_CALIBRATE_DELAY 293 def_bool y 294 295config ARCH_HAS_CPU_RELAX 296 def_bool y 297 298config ARCH_HAS_CACHE_LINE_SIZE 299 def_bool y 300 301config ARCH_HAS_FILTER_PGPROT 302 def_bool y 303 304config HAVE_SETUP_PER_CPU_AREA 305 def_bool y 306 307config NEED_PER_CPU_EMBED_FIRST_CHUNK 308 def_bool y 309 310config NEED_PER_CPU_PAGE_FIRST_CHUNK 311 def_bool y 312 313config ARCH_HIBERNATION_POSSIBLE 314 def_bool y 315 316config ARCH_SUSPEND_POSSIBLE 317 def_bool y 318 319config ARCH_WANT_GENERAL_HUGETLB 320 def_bool y 321 322config ZONE_DMA32 323 def_bool y if X86_64 324 325config AUDIT_ARCH 326 def_bool y if X86_64 327 328config ARCH_SUPPORTS_DEBUG_PAGEALLOC 329 def_bool y 330 331config KASAN_SHADOW_OFFSET 332 hex 333 depends on KASAN 334 default 0xdffffc0000000000 335 336config HAVE_INTEL_TXT 337 def_bool y 338 depends on INTEL_IOMMU && ACPI 339 340config X86_32_SMP 341 def_bool y 342 depends on X86_32 && SMP 343 344config X86_64_SMP 345 def_bool y 346 depends on X86_64 && SMP 347 348config X86_32_LAZY_GS 349 def_bool y 350 depends on X86_32 && !STACKPROTECTOR 351 352config ARCH_SUPPORTS_UPROBES 353 def_bool y 354 355config FIX_EARLYCON_MEM 356 def_bool y 357 358config DYNAMIC_PHYSICAL_MASK 359 bool 360 361config PGTABLE_LEVELS 362 int 363 default 5 if X86_5LEVEL 364 default 4 if X86_64 365 default 3 if X86_PAE 366 default 2 367 368config CC_HAS_SANE_STACKPROTECTOR 369 bool 370 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 371 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 372 help 373 We have to make sure stack protector is unconditionally disabled if 374 the compiler produces broken code. 375 376menu "Processor type and features" 377 378config ZONE_DMA 379 bool "DMA memory allocation support" if EXPERT 380 default y 381 help 382 DMA memory allocation support allows devices with less than 32-bit 383 addressing to allocate within the first 16MB of address space. 384 Disable if no such devices will be used. 385 386 If unsure, say Y. 387 388config SMP 389 bool "Symmetric multi-processing support" 390 ---help--- 391 This enables support for systems with more than one CPU. If you have 392 a system with only one CPU, say N. If you have a system with more 393 than one CPU, say Y. 394 395 If you say N here, the kernel will run on uni- and multiprocessor 396 machines, but will use only one CPU of a multiprocessor machine. If 397 you say Y here, the kernel will run on many, but not all, 398 uniprocessor machines. On a uniprocessor machine, the kernel 399 will run faster if you say N here. 400 401 Note that if you say Y here and choose architecture "586" or 402 "Pentium" under "Processor family", the kernel will not work on 486 403 architectures. Similarly, multiprocessor kernels for the "PPro" 404 architecture may not work on all Pentium based boards. 405 406 People using multiprocessor machines who say Y here should also say 407 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 408 Management" code will be disabled if you say Y here. 409 410 See also <file:Documentation/x86/i386/IO-APIC.rst>, 411 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 412 <http://www.tldp.org/docs.html#howto>. 413 414 If you don't know what to do here, say N. 415 416config X86_FEATURE_NAMES 417 bool "Processor feature human-readable names" if EMBEDDED 418 default y 419 ---help--- 420 This option compiles in a table of x86 feature bits and corresponding 421 names. This is required to support /proc/cpuinfo and a few kernel 422 messages. You can disable this to save space, at the expense of 423 making those few kernel messages show numeric feature bits instead. 424 425 If in doubt, say Y. 426 427config X86_X2APIC 428 bool "Support x2apic" 429 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 430 ---help--- 431 This enables x2apic support on CPUs that have this feature. 432 433 This allows 32-bit apic IDs (so it can support very large systems), 434 and accesses the local apic via MSRs not via mmio. 435 436 If you don't know what to do here, say N. 437 438config X86_MPPARSE 439 bool "Enable MPS table" if ACPI || SFI 440 default y 441 depends on X86_LOCAL_APIC 442 ---help--- 443 For old smp systems that do not have proper acpi support. Newer systems 444 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 445 446config GOLDFISH 447 def_bool y 448 depends on X86_GOLDFISH 449 450config RETPOLINE 451 bool "Avoid speculative indirect branches in kernel" 452 default y 453 select STACK_VALIDATION if HAVE_STACK_VALIDATION 454 help 455 Compile kernel with the retpoline compiler options to guard against 456 kernel-to-user data leaks by avoiding speculative indirect 457 branches. Requires a compiler with -mindirect-branch=thunk-extern 458 support for full protection. The kernel may run slower. 459 460config X86_CPU_RESCTRL 461 bool "x86 CPU resource control support" 462 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 463 select KERNFS 464 select PROC_CPU_RESCTRL if PROC_FS 465 help 466 Enable x86 CPU resource control support. 467 468 Provide support for the allocation and monitoring of system resources 469 usage by the CPU. 470 471 Intel calls this Intel Resource Director Technology 472 (Intel(R) RDT). More information about RDT can be found in the 473 Intel x86 Architecture Software Developer Manual. 474 475 AMD calls this AMD Platform Quality of Service (AMD QoS). 476 More information about AMD QoS can be found in the AMD64 Technology 477 Platform Quality of Service Extensions manual. 478 479 Say N if unsure. 480 481if X86_32 482config X86_BIGSMP 483 bool "Support for big SMP systems with more than 8 CPUs" 484 depends on SMP 485 ---help--- 486 This option is needed for the systems that have more than 8 CPUs. 487 488config X86_EXTENDED_PLATFORM 489 bool "Support for extended (non-PC) x86 platforms" 490 default y 491 ---help--- 492 If you disable this option then the kernel will only support 493 standard PC platforms. (which covers the vast majority of 494 systems out there.) 495 496 If you enable this option then you'll be able to select support 497 for the following (non-PC) 32 bit x86 platforms: 498 Goldfish (Android emulator) 499 AMD Elan 500 RDC R-321x SoC 501 SGI 320/540 (Visual Workstation) 502 STA2X11-based (e.g. Northville) 503 Moorestown MID devices 504 505 If you have one of these systems, or if you want to build a 506 generic distribution kernel, say Y here - otherwise say N. 507endif 508 509if X86_64 510config X86_EXTENDED_PLATFORM 511 bool "Support for extended (non-PC) x86 platforms" 512 default y 513 ---help--- 514 If you disable this option then the kernel will only support 515 standard PC platforms. (which covers the vast majority of 516 systems out there.) 517 518 If you enable this option then you'll be able to select support 519 for the following (non-PC) 64 bit x86 platforms: 520 Numascale NumaChip 521 ScaleMP vSMP 522 SGI Ultraviolet 523 524 If you have one of these systems, or if you want to build a 525 generic distribution kernel, say Y here - otherwise say N. 526endif 527# This is an alphabetically sorted list of 64 bit extended platforms 528# Please maintain the alphabetic order if and when there are additions 529config X86_NUMACHIP 530 bool "Numascale NumaChip" 531 depends on X86_64 532 depends on X86_EXTENDED_PLATFORM 533 depends on NUMA 534 depends on SMP 535 depends on X86_X2APIC 536 depends on PCI_MMCONFIG 537 ---help--- 538 Adds support for Numascale NumaChip large-SMP systems. Needed to 539 enable more than ~168 cores. 540 If you don't have one of these, you should say N here. 541 542config X86_VSMP 543 bool "ScaleMP vSMP" 544 select HYPERVISOR_GUEST 545 select PARAVIRT 546 depends on X86_64 && PCI 547 depends on X86_EXTENDED_PLATFORM 548 depends on SMP 549 ---help--- 550 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 551 supposed to run on these EM64T-based machines. Only choose this option 552 if you have one of these machines. 553 554config X86_UV 555 bool "SGI Ultraviolet" 556 depends on X86_64 557 depends on X86_EXTENDED_PLATFORM 558 depends on NUMA 559 depends on EFI 560 depends on X86_X2APIC 561 depends on PCI 562 ---help--- 563 This option is needed in order to support SGI Ultraviolet systems. 564 If you don't have one of these, you should say N here. 565 566# Following is an alphabetically sorted list of 32 bit extended platforms 567# Please maintain the alphabetic order if and when there are additions 568 569config X86_GOLDFISH 570 bool "Goldfish (Virtual Platform)" 571 depends on X86_EXTENDED_PLATFORM 572 ---help--- 573 Enable support for the Goldfish virtual platform used primarily 574 for Android development. Unless you are building for the Android 575 Goldfish emulator say N here. 576 577config X86_INTEL_CE 578 bool "CE4100 TV platform" 579 depends on PCI 580 depends on PCI_GODIRECT 581 depends on X86_IO_APIC 582 depends on X86_32 583 depends on X86_EXTENDED_PLATFORM 584 select X86_REBOOTFIXUPS 585 select OF 586 select OF_EARLY_FLATTREE 587 ---help--- 588 Select for the Intel CE media processor (CE4100) SOC. 589 This option compiles in support for the CE4100 SOC for settop 590 boxes and media devices. 591 592config X86_INTEL_MID 593 bool "Intel MID platform support" 594 depends on X86_EXTENDED_PLATFORM 595 depends on X86_PLATFORM_DEVICES 596 depends on PCI 597 depends on X86_64 || (PCI_GOANY && X86_32) 598 depends on X86_IO_APIC 599 select SFI 600 select I2C 601 select DW_APB_TIMER 602 select APB_TIMER 603 select INTEL_SCU_PCI 604 select MFD_INTEL_MSIC 605 ---help--- 606 Select to build a kernel capable of supporting Intel MID (Mobile 607 Internet Device) platform systems which do not have the PCI legacy 608 interfaces. If you are building for a PC class system say N here. 609 610 Intel MID platforms are based on an Intel processor and chipset which 611 consume less power than most of the x86 derivatives. 612 613config X86_INTEL_QUARK 614 bool "Intel Quark platform support" 615 depends on X86_32 616 depends on X86_EXTENDED_PLATFORM 617 depends on X86_PLATFORM_DEVICES 618 depends on X86_TSC 619 depends on PCI 620 depends on PCI_GOANY 621 depends on X86_IO_APIC 622 select IOSF_MBI 623 select INTEL_IMR 624 select COMMON_CLK 625 ---help--- 626 Select to include support for Quark X1000 SoC. 627 Say Y here if you have a Quark based system such as the Arduino 628 compatible Intel Galileo. 629 630config X86_INTEL_LPSS 631 bool "Intel Low Power Subsystem Support" 632 depends on X86 && ACPI && PCI 633 select COMMON_CLK 634 select PINCTRL 635 select IOSF_MBI 636 ---help--- 637 Select to build support for Intel Low Power Subsystem such as 638 found on Intel Lynxpoint PCH. Selecting this option enables 639 things like clock tree (common clock framework) and pincontrol 640 which are needed by the LPSS peripheral drivers. 641 642config X86_AMD_PLATFORM_DEVICE 643 bool "AMD ACPI2Platform devices support" 644 depends on ACPI 645 select COMMON_CLK 646 select PINCTRL 647 ---help--- 648 Select to interpret AMD specific ACPI device to platform device 649 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 650 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 651 implemented under PINCTRL subsystem. 652 653config IOSF_MBI 654 tristate "Intel SoC IOSF Sideband support for SoC platforms" 655 depends on PCI 656 ---help--- 657 This option enables sideband register access support for Intel SoC 658 platforms. On these platforms the IOSF sideband is used in lieu of 659 MSR's for some register accesses, mostly but not limited to thermal 660 and power. Drivers may query the availability of this device to 661 determine if they need the sideband in order to work on these 662 platforms. The sideband is available on the following SoC products. 663 This list is not meant to be exclusive. 664 - BayTrail 665 - Braswell 666 - Quark 667 668 You should say Y if you are running a kernel on one of these SoC's. 669 670config IOSF_MBI_DEBUG 671 bool "Enable IOSF sideband access through debugfs" 672 depends on IOSF_MBI && DEBUG_FS 673 ---help--- 674 Select this option to expose the IOSF sideband access registers (MCR, 675 MDR, MCRX) through debugfs to write and read register information from 676 different units on the SoC. This is most useful for obtaining device 677 state information for debug and analysis. As this is a general access 678 mechanism, users of this option would have specific knowledge of the 679 device they want to access. 680 681 If you don't require the option or are in doubt, say N. 682 683config X86_RDC321X 684 bool "RDC R-321x SoC" 685 depends on X86_32 686 depends on X86_EXTENDED_PLATFORM 687 select M486 688 select X86_REBOOTFIXUPS 689 ---help--- 690 This option is needed for RDC R-321x system-on-chip, also known 691 as R-8610-(G). 692 If you don't have one of these chips, you should say N here. 693 694config X86_32_NON_STANDARD 695 bool "Support non-standard 32-bit SMP architectures" 696 depends on X86_32 && SMP 697 depends on X86_EXTENDED_PLATFORM 698 ---help--- 699 This option compiles in the bigsmp and STA2X11 default 700 subarchitectures. It is intended for a generic binary 701 kernel. If you select them all, kernel will probe it one by 702 one and will fallback to default. 703 704# Alphabetically sorted list of Non standard 32 bit platforms 705 706config X86_SUPPORTS_MEMORY_FAILURE 707 def_bool y 708 # MCE code calls memory_failure(): 709 depends on X86_MCE 710 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 711 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 712 depends on X86_64 || !SPARSEMEM 713 select ARCH_SUPPORTS_MEMORY_FAILURE 714 715config STA2X11 716 bool "STA2X11 Companion Chip Support" 717 depends on X86_32_NON_STANDARD && PCI 718 select SWIOTLB 719 select MFD_STA2X11 720 select GPIOLIB 721 ---help--- 722 This adds support for boards based on the STA2X11 IO-Hub, 723 a.k.a. "ConneXt". The chip is used in place of the standard 724 PC chipset, so all "standard" peripherals are missing. If this 725 option is selected the kernel will still be able to boot on 726 standard PC machines. 727 728config X86_32_IRIS 729 tristate "Eurobraille/Iris poweroff module" 730 depends on X86_32 731 ---help--- 732 The Iris machines from EuroBraille do not have APM or ACPI support 733 to shut themselves down properly. A special I/O sequence is 734 needed to do so, which is what this module does at 735 kernel shutdown. 736 737 This is only for Iris machines from EuroBraille. 738 739 If unused, say N. 740 741config SCHED_OMIT_FRAME_POINTER 742 def_bool y 743 prompt "Single-depth WCHAN output" 744 depends on X86 745 ---help--- 746 Calculate simpler /proc/<PID>/wchan values. If this option 747 is disabled then wchan values will recurse back to the 748 caller function. This provides more accurate wchan values, 749 at the expense of slightly more scheduling overhead. 750 751 If in doubt, say "Y". 752 753menuconfig HYPERVISOR_GUEST 754 bool "Linux guest support" 755 ---help--- 756 Say Y here to enable options for running Linux under various hyper- 757 visors. This option enables basic hypervisor detection and platform 758 setup. 759 760 If you say N, all options in this submenu will be skipped and 761 disabled, and Linux guest support won't be built in. 762 763if HYPERVISOR_GUEST 764 765config PARAVIRT 766 bool "Enable paravirtualization code" 767 ---help--- 768 This changes the kernel so it can modify itself when it is run 769 under a hypervisor, potentially improving performance significantly 770 over full virtualization. However, when run without a hypervisor 771 the kernel is theoretically slower and slightly larger. 772 773config PARAVIRT_XXL 774 bool 775 776config PARAVIRT_DEBUG 777 bool "paravirt-ops debugging" 778 depends on PARAVIRT && DEBUG_KERNEL 779 ---help--- 780 Enable to debug paravirt_ops internals. Specifically, BUG if 781 a paravirt_op is missing when it is called. 782 783config PARAVIRT_SPINLOCKS 784 bool "Paravirtualization layer for spinlocks" 785 depends on PARAVIRT && SMP 786 ---help--- 787 Paravirtualized spinlocks allow a pvops backend to replace the 788 spinlock implementation with something virtualization-friendly 789 (for example, block the virtual CPU rather than spinning). 790 791 It has a minimal impact on native kernels and gives a nice performance 792 benefit on paravirtualized KVM / Xen kernels. 793 794 If you are unsure how to answer this question, answer Y. 795 796config X86_HV_CALLBACK_VECTOR 797 def_bool n 798 799source "arch/x86/xen/Kconfig" 800 801config KVM_GUEST 802 bool "KVM Guest support (including kvmclock)" 803 depends on PARAVIRT 804 select PARAVIRT_CLOCK 805 select ARCH_CPUIDLE_HALTPOLL 806 default y 807 ---help--- 808 This option enables various optimizations for running under the KVM 809 hypervisor. It includes a paravirtualized clock, so that instead 810 of relying on a PIT (or probably other) emulation by the 811 underlying device model, the host provides the guest with 812 timing infrastructure such as time of day, and system time 813 814config ARCH_CPUIDLE_HALTPOLL 815 def_bool n 816 prompt "Disable host haltpoll when loading haltpoll driver" 817 help 818 If virtualized under KVM, disable host haltpoll. 819 820config PVH 821 bool "Support for running PVH guests" 822 ---help--- 823 This option enables the PVH entry point for guest virtual machines 824 as specified in the x86/HVM direct boot ABI. 825 826config KVM_DEBUG_FS 827 bool "Enable debug information for KVM Guests in debugfs" 828 depends on KVM_GUEST && DEBUG_FS 829 ---help--- 830 This option enables collection of various statistics for KVM guest. 831 Statistics are displayed in debugfs filesystem. Enabling this option 832 may incur significant overhead. 833 834config PARAVIRT_TIME_ACCOUNTING 835 bool "Paravirtual steal time accounting" 836 depends on PARAVIRT 837 ---help--- 838 Select this option to enable fine granularity task steal time 839 accounting. Time spent executing other tasks in parallel with 840 the current vCPU is discounted from the vCPU power. To account for 841 that, there can be a small performance impact. 842 843 If in doubt, say N here. 844 845config PARAVIRT_CLOCK 846 bool 847 848config JAILHOUSE_GUEST 849 bool "Jailhouse non-root cell support" 850 depends on X86_64 && PCI 851 select X86_PM_TIMER 852 ---help--- 853 This option allows to run Linux as guest in a Jailhouse non-root 854 cell. You can leave this option disabled if you only want to start 855 Jailhouse and run Linux afterwards in the root cell. 856 857config ACRN_GUEST 858 bool "ACRN Guest support" 859 depends on X86_64 860 select X86_HV_CALLBACK_VECTOR 861 help 862 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 863 a flexible, lightweight reference open-source hypervisor, built with 864 real-time and safety-criticality in mind. It is built for embedded 865 IOT with small footprint and real-time features. More details can be 866 found in https://projectacrn.org/. 867 868endif #HYPERVISOR_GUEST 869 870source "arch/x86/Kconfig.cpu" 871 872config HPET_TIMER 873 def_bool X86_64 874 prompt "HPET Timer Support" if X86_32 875 ---help--- 876 Use the IA-PC HPET (High Precision Event Timer) to manage 877 time in preference to the PIT and RTC, if a HPET is 878 present. 879 HPET is the next generation timer replacing legacy 8254s. 880 The HPET provides a stable time base on SMP 881 systems, unlike the TSC, but it is more expensive to access, 882 as it is off-chip. The interface used is documented 883 in the HPET spec, revision 1. 884 885 You can safely choose Y here. However, HPET will only be 886 activated if the platform and the BIOS support this feature. 887 Otherwise the 8254 will be used for timing services. 888 889 Choose N to continue using the legacy 8254 timer. 890 891config HPET_EMULATE_RTC 892 def_bool y 893 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 894 895config APB_TIMER 896 def_bool y if X86_INTEL_MID 897 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 898 select DW_APB_TIMER 899 depends on X86_INTEL_MID && SFI 900 help 901 APB timer is the replacement for 8254, HPET on X86 MID platforms. 902 The APBT provides a stable time base on SMP 903 systems, unlike the TSC, but it is more expensive to access, 904 as it is off-chip. APB timers are always running regardless of CPU 905 C states, they are used as per CPU clockevent device when possible. 906 907# Mark as expert because too many people got it wrong. 908# The code disables itself when not needed. 909config DMI 910 default y 911 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 912 bool "Enable DMI scanning" if EXPERT 913 ---help--- 914 Enabled scanning of DMI to identify machine quirks. Say Y 915 here unless you have verified that your setup is not 916 affected by entries in the DMI blacklist. Required by PNP 917 BIOS code. 918 919config GART_IOMMU 920 bool "Old AMD GART IOMMU support" 921 select IOMMU_HELPER 922 select SWIOTLB 923 depends on X86_64 && PCI && AMD_NB 924 ---help--- 925 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 926 GART based hardware IOMMUs. 927 928 The GART supports full DMA access for devices with 32-bit access 929 limitations, on systems with more than 3 GB. This is usually needed 930 for USB, sound, many IDE/SATA chipsets and some other devices. 931 932 Newer systems typically have a modern AMD IOMMU, supported via 933 the CONFIG_AMD_IOMMU=y config option. 934 935 In normal configurations this driver is only active when needed: 936 there's more than 3 GB of memory and the system contains a 937 32-bit limited device. 938 939 If unsure, say Y. 940 941config MAXSMP 942 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 943 depends on X86_64 && SMP && DEBUG_KERNEL 944 select CPUMASK_OFFSTACK 945 ---help--- 946 Enable maximum number of CPUS and NUMA Nodes for this architecture. 947 If unsure, say N. 948 949# 950# The maximum number of CPUs supported: 951# 952# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 953# and which can be configured interactively in the 954# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 955# 956# The ranges are different on 32-bit and 64-bit kernels, depending on 957# hardware capabilities and scalability features of the kernel. 958# 959# ( If MAXSMP is enabled we just use the highest possible value and disable 960# interactive configuration. ) 961# 962 963config NR_CPUS_RANGE_BEGIN 964 int 965 default NR_CPUS_RANGE_END if MAXSMP 966 default 1 if !SMP 967 default 2 968 969config NR_CPUS_RANGE_END 970 int 971 depends on X86_32 972 default 64 if SMP && X86_BIGSMP 973 default 8 if SMP && !X86_BIGSMP 974 default 1 if !SMP 975 976config NR_CPUS_RANGE_END 977 int 978 depends on X86_64 979 default 8192 if SMP && CPUMASK_OFFSTACK 980 default 512 if SMP && !CPUMASK_OFFSTACK 981 default 1 if !SMP 982 983config NR_CPUS_DEFAULT 984 int 985 depends on X86_32 986 default 32 if X86_BIGSMP 987 default 8 if SMP 988 default 1 if !SMP 989 990config NR_CPUS_DEFAULT 991 int 992 depends on X86_64 993 default 8192 if MAXSMP 994 default 64 if SMP 995 default 1 if !SMP 996 997config NR_CPUS 998 int "Maximum number of CPUs" if SMP && !MAXSMP 999 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1000 default NR_CPUS_DEFAULT 1001 ---help--- 1002 This allows you to specify the maximum number of CPUs which this 1003 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1004 supported value is 8192, otherwise the maximum value is 512. The 1005 minimum value which makes sense is 2. 1006 1007 This is purely to save memory: each supported CPU adds about 8KB 1008 to the kernel image. 1009 1010config SCHED_SMT 1011 def_bool y if SMP 1012 1013config SCHED_MC 1014 def_bool y 1015 prompt "Multi-core scheduler support" 1016 depends on SMP 1017 ---help--- 1018 Multi-core scheduler support improves the CPU scheduler's decision 1019 making when dealing with multi-core CPU chips at a cost of slightly 1020 increased overhead in some places. If unsure say N here. 1021 1022config SCHED_MC_PRIO 1023 bool "CPU core priorities scheduler support" 1024 depends on SCHED_MC && CPU_SUP_INTEL 1025 select X86_INTEL_PSTATE 1026 select CPU_FREQ 1027 default y 1028 ---help--- 1029 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1030 core ordering determined at manufacturing time, which allows 1031 certain cores to reach higher turbo frequencies (when running 1032 single threaded workloads) than others. 1033 1034 Enabling this kernel feature teaches the scheduler about 1035 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1036 scheduler's CPU selection logic accordingly, so that higher 1037 overall system performance can be achieved. 1038 1039 This feature will have no effect on CPUs without this feature. 1040 1041 If unsure say Y here. 1042 1043config UP_LATE_INIT 1044 def_bool y 1045 depends on !SMP && X86_LOCAL_APIC 1046 1047config X86_UP_APIC 1048 bool "Local APIC support on uniprocessors" if !PCI_MSI 1049 default PCI_MSI 1050 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1051 ---help--- 1052 A local APIC (Advanced Programmable Interrupt Controller) is an 1053 integrated interrupt controller in the CPU. If you have a single-CPU 1054 system which has a processor with a local APIC, you can say Y here to 1055 enable and use it. If you say Y here even though your machine doesn't 1056 have a local APIC, then the kernel will still run with no slowdown at 1057 all. The local APIC supports CPU-generated self-interrupts (timer, 1058 performance counters), and the NMI watchdog which detects hard 1059 lockups. 1060 1061config X86_UP_IOAPIC 1062 bool "IO-APIC support on uniprocessors" 1063 depends on X86_UP_APIC 1064 ---help--- 1065 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1066 SMP-capable replacement for PC-style interrupt controllers. Most 1067 SMP systems and many recent uniprocessor systems have one. 1068 1069 If you have a single-CPU system with an IO-APIC, you can say Y here 1070 to use it. If you say Y here even though your machine doesn't have 1071 an IO-APIC, then the kernel will still run with no slowdown at all. 1072 1073config X86_LOCAL_APIC 1074 def_bool y 1075 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1076 select IRQ_DOMAIN_HIERARCHY 1077 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1078 1079config X86_IO_APIC 1080 def_bool y 1081 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1082 1083config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1084 bool "Reroute for broken boot IRQs" 1085 depends on X86_IO_APIC 1086 ---help--- 1087 This option enables a workaround that fixes a source of 1088 spurious interrupts. This is recommended when threaded 1089 interrupt handling is used on systems where the generation of 1090 superfluous "boot interrupts" cannot be disabled. 1091 1092 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1093 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1094 kernel does during interrupt handling). On chipsets where this 1095 boot IRQ generation cannot be disabled, this workaround keeps 1096 the original IRQ line masked so that only the equivalent "boot 1097 IRQ" is delivered to the CPUs. The workaround also tells the 1098 kernel to set up the IRQ handler on the boot IRQ line. In this 1099 way only one interrupt is delivered to the kernel. Otherwise 1100 the spurious second interrupt may cause the kernel to bring 1101 down (vital) interrupt lines. 1102 1103 Only affects "broken" chipsets. Interrupt sharing may be 1104 increased on these systems. 1105 1106config X86_MCE 1107 bool "Machine Check / overheating reporting" 1108 select GENERIC_ALLOCATOR 1109 default y 1110 ---help--- 1111 Machine Check support allows the processor to notify the 1112 kernel if it detects a problem (e.g. overheating, data corruption). 1113 The action the kernel takes depends on the severity of the problem, 1114 ranging from warning messages to halting the machine. 1115 1116config X86_MCELOG_LEGACY 1117 bool "Support for deprecated /dev/mcelog character device" 1118 depends on X86_MCE 1119 ---help--- 1120 Enable support for /dev/mcelog which is needed by the old mcelog 1121 userspace logging daemon. Consider switching to the new generation 1122 rasdaemon solution. 1123 1124config X86_MCE_INTEL 1125 def_bool y 1126 prompt "Intel MCE features" 1127 depends on X86_MCE && X86_LOCAL_APIC 1128 ---help--- 1129 Additional support for intel specific MCE features such as 1130 the thermal monitor. 1131 1132config X86_MCE_AMD 1133 def_bool y 1134 prompt "AMD MCE features" 1135 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1136 ---help--- 1137 Additional support for AMD specific MCE features such as 1138 the DRAM Error Threshold. 1139 1140config X86_ANCIENT_MCE 1141 bool "Support for old Pentium 5 / WinChip machine checks" 1142 depends on X86_32 && X86_MCE 1143 ---help--- 1144 Include support for machine check handling on old Pentium 5 or WinChip 1145 systems. These typically need to be enabled explicitly on the command 1146 line. 1147 1148config X86_MCE_THRESHOLD 1149 depends on X86_MCE_AMD || X86_MCE_INTEL 1150 def_bool y 1151 1152config X86_MCE_INJECT 1153 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1154 tristate "Machine check injector support" 1155 ---help--- 1156 Provide support for injecting machine checks for testing purposes. 1157 If you don't know what a machine check is and you don't do kernel 1158 QA it is safe to say n. 1159 1160config X86_THERMAL_VECTOR 1161 def_bool y 1162 depends on X86_MCE_INTEL 1163 1164source "arch/x86/events/Kconfig" 1165 1166config X86_LEGACY_VM86 1167 bool "Legacy VM86 support" 1168 depends on X86_32 1169 ---help--- 1170 This option allows user programs to put the CPU into V8086 1171 mode, which is an 80286-era approximation of 16-bit real mode. 1172 1173 Some very old versions of X and/or vbetool require this option 1174 for user mode setting. Similarly, DOSEMU will use it if 1175 available to accelerate real mode DOS programs. However, any 1176 recent version of DOSEMU, X, or vbetool should be fully 1177 functional even without kernel VM86 support, as they will all 1178 fall back to software emulation. Nevertheless, if you are using 1179 a 16-bit DOS program where 16-bit performance matters, vm86 1180 mode might be faster than emulation and you might want to 1181 enable this option. 1182 1183 Note that any app that works on a 64-bit kernel is unlikely to 1184 need this option, as 64-bit kernels don't, and can't, support 1185 V8086 mode. This option is also unrelated to 16-bit protected 1186 mode and is not needed to run most 16-bit programs under Wine. 1187 1188 Enabling this option increases the complexity of the kernel 1189 and slows down exception handling a tiny bit. 1190 1191 If unsure, say N here. 1192 1193config VM86 1194 bool 1195 default X86_LEGACY_VM86 1196 1197config X86_16BIT 1198 bool "Enable support for 16-bit segments" if EXPERT 1199 default y 1200 depends on MODIFY_LDT_SYSCALL 1201 ---help--- 1202 This option is required by programs like Wine to run 16-bit 1203 protected mode legacy code on x86 processors. Disabling 1204 this option saves about 300 bytes on i386, or around 6K text 1205 plus 16K runtime memory on x86-64, 1206 1207config X86_ESPFIX32 1208 def_bool y 1209 depends on X86_16BIT && X86_32 1210 1211config X86_ESPFIX64 1212 def_bool y 1213 depends on X86_16BIT && X86_64 1214 1215config X86_VSYSCALL_EMULATION 1216 bool "Enable vsyscall emulation" if EXPERT 1217 default y 1218 depends on X86_64 1219 ---help--- 1220 This enables emulation of the legacy vsyscall page. Disabling 1221 it is roughly equivalent to booting with vsyscall=none, except 1222 that it will also disable the helpful warning if a program 1223 tries to use a vsyscall. With this option set to N, offending 1224 programs will just segfault, citing addresses of the form 1225 0xffffffffff600?00. 1226 1227 This option is required by many programs built before 2013, and 1228 care should be used even with newer programs if set to N. 1229 1230 Disabling this option saves about 7K of kernel size and 1231 possibly 4K of additional runtime pagetable memory. 1232 1233config X86_IOPL_IOPERM 1234 bool "IOPERM and IOPL Emulation" 1235 default y 1236 ---help--- 1237 This enables the ioperm() and iopl() syscalls which are necessary 1238 for legacy applications. 1239 1240 Legacy IOPL support is an overbroad mechanism which allows user 1241 space aside of accessing all 65536 I/O ports also to disable 1242 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1243 capabilities and permission from potentially active security 1244 modules. 1245 1246 The emulation restricts the functionality of the syscall to 1247 only allowing the full range I/O port access, but prevents the 1248 ability to disable interrupts from user space which would be 1249 granted if the hardware IOPL mechanism would be used. 1250 1251config TOSHIBA 1252 tristate "Toshiba Laptop support" 1253 depends on X86_32 1254 ---help--- 1255 This adds a driver to safely access the System Management Mode of 1256 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1257 not work on models with a Phoenix BIOS. The System Management Mode 1258 is used to set the BIOS and power saving options on Toshiba portables. 1259 1260 For information on utilities to make use of this driver see the 1261 Toshiba Linux utilities web site at: 1262 <http://www.buzzard.org.uk/toshiba/>. 1263 1264 Say Y if you intend to run this kernel on a Toshiba portable. 1265 Say N otherwise. 1266 1267config I8K 1268 tristate "Dell i8k legacy laptop support" 1269 select HWMON 1270 select SENSORS_DELL_SMM 1271 ---help--- 1272 This option enables legacy /proc/i8k userspace interface in hwmon 1273 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1274 temperature and allows controlling fan speeds of Dell laptops via 1275 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1276 it reports also power and hotkey status. For fan speed control is 1277 needed userspace package i8kutils. 1278 1279 Say Y if you intend to run this kernel on old Dell laptops or want to 1280 use userspace package i8kutils. 1281 Say N otherwise. 1282 1283config X86_REBOOTFIXUPS 1284 bool "Enable X86 board specific fixups for reboot" 1285 depends on X86_32 1286 ---help--- 1287 This enables chipset and/or board specific fixups to be done 1288 in order to get reboot to work correctly. This is only needed on 1289 some combinations of hardware and BIOS. The symptom, for which 1290 this config is intended, is when reboot ends with a stalled/hung 1291 system. 1292 1293 Currently, the only fixup is for the Geode machines using 1294 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1295 1296 Say Y if you want to enable the fixup. Currently, it's safe to 1297 enable this option even if you don't need it. 1298 Say N otherwise. 1299 1300config MICROCODE 1301 bool "CPU microcode loading support" 1302 default y 1303 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1304 select FW_LOADER 1305 ---help--- 1306 If you say Y here, you will be able to update the microcode on 1307 Intel and AMD processors. The Intel support is for the IA32 family, 1308 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1309 AMD support is for families 0x10 and later. You will obviously need 1310 the actual microcode binary data itself which is not shipped with 1311 the Linux kernel. 1312 1313 The preferred method to load microcode from a detached initrd is described 1314 in Documentation/x86/microcode.rst. For that you need to enable 1315 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1316 initrd for microcode blobs. 1317 1318 In addition, you can build the microcode into the kernel. For that you 1319 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1320 config option. 1321 1322config MICROCODE_INTEL 1323 bool "Intel microcode loading support" 1324 depends on MICROCODE 1325 default MICROCODE 1326 select FW_LOADER 1327 ---help--- 1328 This options enables microcode patch loading support for Intel 1329 processors. 1330 1331 For the current Intel microcode data package go to 1332 <https://downloadcenter.intel.com> and search for 1333 'Linux Processor Microcode Data File'. 1334 1335config MICROCODE_AMD 1336 bool "AMD microcode loading support" 1337 depends on MICROCODE 1338 select FW_LOADER 1339 ---help--- 1340 If you select this option, microcode patch loading support for AMD 1341 processors will be enabled. 1342 1343config MICROCODE_OLD_INTERFACE 1344 bool "Ancient loading interface (DEPRECATED)" 1345 default n 1346 depends on MICROCODE 1347 ---help--- 1348 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1349 which was used by userspace tools like iucode_tool and microcode.ctl. 1350 It is inadequate because it runs too late to be able to properly 1351 load microcode on a machine and it needs special tools. Instead, you 1352 should've switched to the early loading method with the initrd or 1353 builtin microcode by now: Documentation/x86/microcode.rst 1354 1355config X86_MSR 1356 tristate "/dev/cpu/*/msr - Model-specific register support" 1357 ---help--- 1358 This device gives privileged processes access to the x86 1359 Model-Specific Registers (MSRs). It is a character device with 1360 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1361 MSR accesses are directed to a specific CPU on multi-processor 1362 systems. 1363 1364config X86_CPUID 1365 tristate "/dev/cpu/*/cpuid - CPU information support" 1366 ---help--- 1367 This device gives processes access to the x86 CPUID instruction to 1368 be executed on a specific processor. It is a character device 1369 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1370 /dev/cpu/31/cpuid. 1371 1372choice 1373 prompt "High Memory Support" 1374 default HIGHMEM4G 1375 depends on X86_32 1376 1377config NOHIGHMEM 1378 bool "off" 1379 ---help--- 1380 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1381 However, the address space of 32-bit x86 processors is only 4 1382 Gigabytes large. That means that, if you have a large amount of 1383 physical memory, not all of it can be "permanently mapped" by the 1384 kernel. The physical memory that's not permanently mapped is called 1385 "high memory". 1386 1387 If you are compiling a kernel which will never run on a machine with 1388 more than 1 Gigabyte total physical RAM, answer "off" here (default 1389 choice and suitable for most users). This will result in a "3GB/1GB" 1390 split: 3GB are mapped so that each process sees a 3GB virtual memory 1391 space and the remaining part of the 4GB virtual memory space is used 1392 by the kernel to permanently map as much physical memory as 1393 possible. 1394 1395 If the machine has between 1 and 4 Gigabytes physical RAM, then 1396 answer "4GB" here. 1397 1398 If more than 4 Gigabytes is used then answer "64GB" here. This 1399 selection turns Intel PAE (Physical Address Extension) mode on. 1400 PAE implements 3-level paging on IA32 processors. PAE is fully 1401 supported by Linux, PAE mode is implemented on all recent Intel 1402 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1403 then the kernel will not boot on CPUs that don't support PAE! 1404 1405 The actual amount of total physical memory will either be 1406 auto detected or can be forced by using a kernel command line option 1407 such as "mem=256M". (Try "man bootparam" or see the documentation of 1408 your boot loader (lilo or loadlin) about how to pass options to the 1409 kernel at boot time.) 1410 1411 If unsure, say "off". 1412 1413config HIGHMEM4G 1414 bool "4GB" 1415 ---help--- 1416 Select this if you have a 32-bit processor and between 1 and 4 1417 gigabytes of physical RAM. 1418 1419config HIGHMEM64G 1420 bool "64GB" 1421 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1422 select X86_PAE 1423 ---help--- 1424 Select this if you have a 32-bit processor and more than 4 1425 gigabytes of physical RAM. 1426 1427endchoice 1428 1429choice 1430 prompt "Memory split" if EXPERT 1431 default VMSPLIT_3G 1432 depends on X86_32 1433 ---help--- 1434 Select the desired split between kernel and user memory. 1435 1436 If the address range available to the kernel is less than the 1437 physical memory installed, the remaining memory will be available 1438 as "high memory". Accessing high memory is a little more costly 1439 than low memory, as it needs to be mapped into the kernel first. 1440 Note that increasing the kernel address space limits the range 1441 available to user programs, making the address space there 1442 tighter. Selecting anything other than the default 3G/1G split 1443 will also likely make your kernel incompatible with binary-only 1444 kernel modules. 1445 1446 If you are not absolutely sure what you are doing, leave this 1447 option alone! 1448 1449 config VMSPLIT_3G 1450 bool "3G/1G user/kernel split" 1451 config VMSPLIT_3G_OPT 1452 depends on !X86_PAE 1453 bool "3G/1G user/kernel split (for full 1G low memory)" 1454 config VMSPLIT_2G 1455 bool "2G/2G user/kernel split" 1456 config VMSPLIT_2G_OPT 1457 depends on !X86_PAE 1458 bool "2G/2G user/kernel split (for full 2G low memory)" 1459 config VMSPLIT_1G 1460 bool "1G/3G user/kernel split" 1461endchoice 1462 1463config PAGE_OFFSET 1464 hex 1465 default 0xB0000000 if VMSPLIT_3G_OPT 1466 default 0x80000000 if VMSPLIT_2G 1467 default 0x78000000 if VMSPLIT_2G_OPT 1468 default 0x40000000 if VMSPLIT_1G 1469 default 0xC0000000 1470 depends on X86_32 1471 1472config HIGHMEM 1473 def_bool y 1474 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1475 1476config X86_PAE 1477 bool "PAE (Physical Address Extension) Support" 1478 depends on X86_32 && !HIGHMEM4G 1479 select PHYS_ADDR_T_64BIT 1480 select SWIOTLB 1481 ---help--- 1482 PAE is required for NX support, and furthermore enables 1483 larger swapspace support for non-overcommit purposes. It 1484 has the cost of more pagetable lookup overhead, and also 1485 consumes more pagetable space per process. 1486 1487config X86_5LEVEL 1488 bool "Enable 5-level page tables support" 1489 default y 1490 select DYNAMIC_MEMORY_LAYOUT 1491 select SPARSEMEM_VMEMMAP 1492 depends on X86_64 1493 ---help--- 1494 5-level paging enables access to larger address space: 1495 upto 128 PiB of virtual address space and 4 PiB of 1496 physical address space. 1497 1498 It will be supported by future Intel CPUs. 1499 1500 A kernel with the option enabled can be booted on machines that 1501 support 4- or 5-level paging. 1502 1503 See Documentation/x86/x86_64/5level-paging.rst for more 1504 information. 1505 1506 Say N if unsure. 1507 1508config X86_DIRECT_GBPAGES 1509 def_bool y 1510 depends on X86_64 1511 ---help--- 1512 Certain kernel features effectively disable kernel 1513 linear 1 GB mappings (even if the CPU otherwise 1514 supports them), so don't confuse the user by printing 1515 that we have them enabled. 1516 1517config X86_CPA_STATISTICS 1518 bool "Enable statistic for Change Page Attribute" 1519 depends on DEBUG_FS 1520 ---help--- 1521 Expose statistics about the Change Page Attribute mechanism, which 1522 helps to determine the effectiveness of preserving large and huge 1523 page mappings when mapping protections are changed. 1524 1525config AMD_MEM_ENCRYPT 1526 bool "AMD Secure Memory Encryption (SME) support" 1527 depends on X86_64 && CPU_SUP_AMD 1528 select DMA_COHERENT_POOL 1529 select DYNAMIC_PHYSICAL_MASK 1530 select ARCH_USE_MEMREMAP_PROT 1531 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1532 ---help--- 1533 Say yes to enable support for the encryption of system memory. 1534 This requires an AMD processor that supports Secure Memory 1535 Encryption (SME). 1536 1537config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1538 bool "Activate AMD Secure Memory Encryption (SME) by default" 1539 default y 1540 depends on AMD_MEM_ENCRYPT 1541 ---help--- 1542 Say yes to have system memory encrypted by default if running on 1543 an AMD processor that supports Secure Memory Encryption (SME). 1544 1545 If set to Y, then the encryption of system memory can be 1546 deactivated with the mem_encrypt=off command line option. 1547 1548 If set to N, then the encryption of system memory can be 1549 activated with the mem_encrypt=on command line option. 1550 1551# Common NUMA Features 1552config NUMA 1553 bool "NUMA Memory Allocation and Scheduler Support" 1554 depends on SMP 1555 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1556 default y if X86_BIGSMP 1557 ---help--- 1558 Enable NUMA (Non-Uniform Memory Access) support. 1559 1560 The kernel will try to allocate memory used by a CPU on the 1561 local memory controller of the CPU and add some more 1562 NUMA awareness to the kernel. 1563 1564 For 64-bit this is recommended if the system is Intel Core i7 1565 (or later), AMD Opteron, or EM64T NUMA. 1566 1567 For 32-bit this is only needed if you boot a 32-bit 1568 kernel on a 64-bit NUMA platform. 1569 1570 Otherwise, you should say N. 1571 1572config AMD_NUMA 1573 def_bool y 1574 prompt "Old style AMD Opteron NUMA detection" 1575 depends on X86_64 && NUMA && PCI 1576 ---help--- 1577 Enable AMD NUMA node topology detection. You should say Y here if 1578 you have a multi processor AMD system. This uses an old method to 1579 read the NUMA configuration directly from the builtin Northbridge 1580 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1581 which also takes priority if both are compiled in. 1582 1583config X86_64_ACPI_NUMA 1584 def_bool y 1585 prompt "ACPI NUMA detection" 1586 depends on X86_64 && NUMA && ACPI && PCI 1587 select ACPI_NUMA 1588 ---help--- 1589 Enable ACPI SRAT based node topology detection. 1590 1591config NUMA_EMU 1592 bool "NUMA emulation" 1593 depends on NUMA 1594 ---help--- 1595 Enable NUMA emulation. A flat machine will be split 1596 into virtual nodes when booted with "numa=fake=N", where N is the 1597 number of nodes. This is only useful for debugging. 1598 1599config NODES_SHIFT 1600 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1601 range 1 10 1602 default "10" if MAXSMP 1603 default "6" if X86_64 1604 default "3" 1605 depends on NEED_MULTIPLE_NODES 1606 ---help--- 1607 Specify the maximum number of NUMA Nodes available on the target 1608 system. Increases memory reserved to accommodate various tables. 1609 1610config ARCH_FLATMEM_ENABLE 1611 def_bool y 1612 depends on X86_32 && !NUMA 1613 1614config ARCH_SPARSEMEM_ENABLE 1615 def_bool y 1616 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1617 select SPARSEMEM_STATIC if X86_32 1618 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1619 1620config ARCH_SPARSEMEM_DEFAULT 1621 def_bool X86_64 || (NUMA && X86_32) 1622 1623config ARCH_SELECT_MEMORY_MODEL 1624 def_bool y 1625 depends on ARCH_SPARSEMEM_ENABLE 1626 1627config ARCH_MEMORY_PROBE 1628 bool "Enable sysfs memory/probe interface" 1629 depends on X86_64 && MEMORY_HOTPLUG 1630 help 1631 This option enables a sysfs memory/probe interface for testing. 1632 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1633 If you are unsure how to answer this question, answer N. 1634 1635config ARCH_PROC_KCORE_TEXT 1636 def_bool y 1637 depends on X86_64 && PROC_KCORE 1638 1639config ILLEGAL_POINTER_VALUE 1640 hex 1641 default 0 if X86_32 1642 default 0xdead000000000000 if X86_64 1643 1644config X86_PMEM_LEGACY_DEVICE 1645 bool 1646 1647config X86_PMEM_LEGACY 1648 tristate "Support non-standard NVDIMMs and ADR protected memory" 1649 depends on PHYS_ADDR_T_64BIT 1650 depends on BLK_DEV 1651 select X86_PMEM_LEGACY_DEVICE 1652 select NUMA_KEEP_MEMINFO if NUMA 1653 select LIBNVDIMM 1654 help 1655 Treat memory marked using the non-standard e820 type of 12 as used 1656 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1657 The kernel will offer these regions to the 'pmem' driver so 1658 they can be used for persistent storage. 1659 1660 Say Y if unsure. 1661 1662config HIGHPTE 1663 bool "Allocate 3rd-level pagetables from highmem" 1664 depends on HIGHMEM 1665 ---help--- 1666 The VM uses one page table entry for each page of physical memory. 1667 For systems with a lot of RAM, this can be wasteful of precious 1668 low memory. Setting this option will put user-space page table 1669 entries in high memory. 1670 1671config X86_CHECK_BIOS_CORRUPTION 1672 bool "Check for low memory corruption" 1673 ---help--- 1674 Periodically check for memory corruption in low memory, which 1675 is suspected to be caused by BIOS. Even when enabled in the 1676 configuration, it is disabled at runtime. Enable it by 1677 setting "memory_corruption_check=1" on the kernel command 1678 line. By default it scans the low 64k of memory every 60 1679 seconds; see the memory_corruption_check_size and 1680 memory_corruption_check_period parameters in 1681 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1682 1683 When enabled with the default parameters, this option has 1684 almost no overhead, as it reserves a relatively small amount 1685 of memory and scans it infrequently. It both detects corruption 1686 and prevents it from affecting the running system. 1687 1688 It is, however, intended as a diagnostic tool; if repeatable 1689 BIOS-originated corruption always affects the same memory, 1690 you can use memmap= to prevent the kernel from using that 1691 memory. 1692 1693config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1694 bool "Set the default setting of memory_corruption_check" 1695 depends on X86_CHECK_BIOS_CORRUPTION 1696 default y 1697 ---help--- 1698 Set whether the default state of memory_corruption_check is 1699 on or off. 1700 1701config X86_RESERVE_LOW 1702 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1703 default 64 1704 range 4 640 1705 ---help--- 1706 Specify the amount of low memory to reserve for the BIOS. 1707 1708 The first page contains BIOS data structures that the kernel 1709 must not use, so that page must always be reserved. 1710 1711 By default we reserve the first 64K of physical RAM, as a 1712 number of BIOSes are known to corrupt that memory range 1713 during events such as suspend/resume or monitor cable 1714 insertion, so it must not be used by the kernel. 1715 1716 You can set this to 4 if you are absolutely sure that you 1717 trust the BIOS to get all its memory reservations and usages 1718 right. If you know your BIOS have problems beyond the 1719 default 64K area, you can set this to 640 to avoid using the 1720 entire low memory range. 1721 1722 If you have doubts about the BIOS (e.g. suspend/resume does 1723 not work or there's kernel crashes after certain hardware 1724 hotplug events) then you might want to enable 1725 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1726 typical corruption patterns. 1727 1728 Leave this to the default value of 64 if you are unsure. 1729 1730config MATH_EMULATION 1731 bool 1732 depends on MODIFY_LDT_SYSCALL 1733 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1734 ---help--- 1735 Linux can emulate a math coprocessor (used for floating point 1736 operations) if you don't have one. 486DX and Pentium processors have 1737 a math coprocessor built in, 486SX and 386 do not, unless you added 1738 a 487DX or 387, respectively. (The messages during boot time can 1739 give you some hints here ["man dmesg"].) Everyone needs either a 1740 coprocessor or this emulation. 1741 1742 If you don't have a math coprocessor, you need to say Y here; if you 1743 say Y here even though you have a coprocessor, the coprocessor will 1744 be used nevertheless. (This behavior can be changed with the kernel 1745 command line option "no387", which comes handy if your coprocessor 1746 is broken. Try "man bootparam" or see the documentation of your boot 1747 loader (lilo or loadlin) about how to pass options to the kernel at 1748 boot time.) This means that it is a good idea to say Y here if you 1749 intend to use this kernel on different machines. 1750 1751 More information about the internals of the Linux math coprocessor 1752 emulation can be found in <file:arch/x86/math-emu/README>. 1753 1754 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1755 kernel, it won't hurt. 1756 1757config MTRR 1758 def_bool y 1759 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1760 ---help--- 1761 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1762 the Memory Type Range Registers (MTRRs) may be used to control 1763 processor access to memory ranges. This is most useful if you have 1764 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1765 allows bus write transfers to be combined into a larger transfer 1766 before bursting over the PCI/AGP bus. This can increase performance 1767 of image write operations 2.5 times or more. Saying Y here creates a 1768 /proc/mtrr file which may be used to manipulate your processor's 1769 MTRRs. Typically the X server should use this. 1770 1771 This code has a reasonably generic interface so that similar 1772 control registers on other processors can be easily supported 1773 as well: 1774 1775 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1776 Registers (ARRs) which provide a similar functionality to MTRRs. For 1777 these, the ARRs are used to emulate the MTRRs. 1778 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1779 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1780 write-combining. All of these processors are supported by this code 1781 and it makes sense to say Y here if you have one of them. 1782 1783 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1784 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1785 can lead to all sorts of problems, so it's good to say Y here. 1786 1787 You can safely say Y even if your machine doesn't have MTRRs, you'll 1788 just add about 9 KB to your kernel. 1789 1790 See <file:Documentation/x86/mtrr.rst> for more information. 1791 1792config MTRR_SANITIZER 1793 def_bool y 1794 prompt "MTRR cleanup support" 1795 depends on MTRR 1796 ---help--- 1797 Convert MTRR layout from continuous to discrete, so X drivers can 1798 add writeback entries. 1799 1800 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1801 The largest mtrr entry size for a continuous block can be set with 1802 mtrr_chunk_size. 1803 1804 If unsure, say Y. 1805 1806config MTRR_SANITIZER_ENABLE_DEFAULT 1807 int "MTRR cleanup enable value (0-1)" 1808 range 0 1 1809 default "0" 1810 depends on MTRR_SANITIZER 1811 ---help--- 1812 Enable mtrr cleanup default value 1813 1814config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1815 int "MTRR cleanup spare reg num (0-7)" 1816 range 0 7 1817 default "1" 1818 depends on MTRR_SANITIZER 1819 ---help--- 1820 mtrr cleanup spare entries default, it can be changed via 1821 mtrr_spare_reg_nr=N on the kernel command line. 1822 1823config X86_PAT 1824 def_bool y 1825 prompt "x86 PAT support" if EXPERT 1826 depends on MTRR 1827 ---help--- 1828 Use PAT attributes to setup page level cache control. 1829 1830 PATs are the modern equivalents of MTRRs and are much more 1831 flexible than MTRRs. 1832 1833 Say N here if you see bootup problems (boot crash, boot hang, 1834 spontaneous reboots) or a non-working video driver. 1835 1836 If unsure, say Y. 1837 1838config ARCH_USES_PG_UNCACHED 1839 def_bool y 1840 depends on X86_PAT 1841 1842config ARCH_RANDOM 1843 def_bool y 1844 prompt "x86 architectural random number generator" if EXPERT 1845 ---help--- 1846 Enable the x86 architectural RDRAND instruction 1847 (Intel Bull Mountain technology) to generate random numbers. 1848 If supported, this is a high bandwidth, cryptographically 1849 secure hardware random number generator. 1850 1851config X86_SMAP 1852 def_bool y 1853 prompt "Supervisor Mode Access Prevention" if EXPERT 1854 ---help--- 1855 Supervisor Mode Access Prevention (SMAP) is a security 1856 feature in newer Intel processors. There is a small 1857 performance cost if this enabled and turned on; there is 1858 also a small increase in the kernel size if this is enabled. 1859 1860 If unsure, say Y. 1861 1862config X86_UMIP 1863 def_bool y 1864 prompt "User Mode Instruction Prevention" if EXPERT 1865 ---help--- 1866 User Mode Instruction Prevention (UMIP) is a security feature in 1867 some x86 processors. If enabled, a general protection fault is 1868 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1869 executed in user mode. These instructions unnecessarily expose 1870 information about the hardware state. 1871 1872 The vast majority of applications do not use these instructions. 1873 For the very few that do, software emulation is provided in 1874 specific cases in protected and virtual-8086 modes. Emulated 1875 results are dummy. 1876 1877config X86_INTEL_MEMORY_PROTECTION_KEYS 1878 prompt "Memory Protection Keys" 1879 def_bool y 1880 # Note: only available in 64-bit mode 1881 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1882 select ARCH_USES_HIGH_VMA_FLAGS 1883 select ARCH_HAS_PKEYS 1884 ---help--- 1885 Memory Protection Keys provides a mechanism for enforcing 1886 page-based protections, but without requiring modification of the 1887 page tables when an application changes protection domains. 1888 1889 For details, see Documentation/core-api/protection-keys.rst 1890 1891 If unsure, say y. 1892 1893choice 1894 prompt "TSX enable mode" 1895 depends on CPU_SUP_INTEL 1896 default X86_INTEL_TSX_MODE_OFF 1897 help 1898 Intel's TSX (Transactional Synchronization Extensions) feature 1899 allows to optimize locking protocols through lock elision which 1900 can lead to a noticeable performance boost. 1901 1902 On the other hand it has been shown that TSX can be exploited 1903 to form side channel attacks (e.g. TAA) and chances are there 1904 will be more of those attacks discovered in the future. 1905 1906 Therefore TSX is not enabled by default (aka tsx=off). An admin 1907 might override this decision by tsx=on the command line parameter. 1908 Even with TSX enabled, the kernel will attempt to enable the best 1909 possible TAA mitigation setting depending on the microcode available 1910 for the particular machine. 1911 1912 This option allows to set the default tsx mode between tsx=on, =off 1913 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1914 details. 1915 1916 Say off if not sure, auto if TSX is in use but it should be used on safe 1917 platforms or on if TSX is in use and the security aspect of tsx is not 1918 relevant. 1919 1920config X86_INTEL_TSX_MODE_OFF 1921 bool "off" 1922 help 1923 TSX is disabled if possible - equals to tsx=off command line parameter. 1924 1925config X86_INTEL_TSX_MODE_ON 1926 bool "on" 1927 help 1928 TSX is always enabled on TSX capable HW - equals the tsx=on command 1929 line parameter. 1930 1931config X86_INTEL_TSX_MODE_AUTO 1932 bool "auto" 1933 help 1934 TSX is enabled on TSX capable HW that is believed to be safe against 1935 side channel attacks- equals the tsx=auto command line parameter. 1936endchoice 1937 1938config EFI 1939 bool "EFI runtime service support" 1940 depends on ACPI 1941 select UCS2_STRING 1942 select EFI_RUNTIME_WRAPPERS 1943 ---help--- 1944 This enables the kernel to use EFI runtime services that are 1945 available (such as the EFI variable services). 1946 1947 This option is only useful on systems that have EFI firmware. 1948 In addition, you should use the latest ELILO loader available 1949 at <http://elilo.sourceforge.net> in order to take advantage 1950 of EFI runtime services. However, even with this option, the 1951 resultant kernel should continue to boot on existing non-EFI 1952 platforms. 1953 1954config EFI_STUB 1955 bool "EFI stub support" 1956 depends on EFI && !X86_USE_3DNOW 1957 depends on $(cc-option,-mabi=ms) || X86_32 1958 select RELOCATABLE 1959 ---help--- 1960 This kernel feature allows a bzImage to be loaded directly 1961 by EFI firmware without the use of a bootloader. 1962 1963 See Documentation/admin-guide/efi-stub.rst for more information. 1964 1965config EFI_MIXED 1966 bool "EFI mixed-mode support" 1967 depends on EFI_STUB && X86_64 1968 ---help--- 1969 Enabling this feature allows a 64-bit kernel to be booted 1970 on a 32-bit firmware, provided that your CPU supports 64-bit 1971 mode. 1972 1973 Note that it is not possible to boot a mixed-mode enabled 1974 kernel via the EFI boot stub - a bootloader that supports 1975 the EFI handover protocol must be used. 1976 1977 If unsure, say N. 1978 1979config SECCOMP 1980 def_bool y 1981 prompt "Enable seccomp to safely compute untrusted bytecode" 1982 ---help--- 1983 This kernel feature is useful for number crunching applications 1984 that may need to compute untrusted bytecode during their 1985 execution. By using pipes or other transports made available to 1986 the process as file descriptors supporting the read/write 1987 syscalls, it's possible to isolate those applications in 1988 their own address space using seccomp. Once seccomp is 1989 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 1990 and the task is only allowed to execute a few safe syscalls 1991 defined by each seccomp mode. 1992 1993 If unsure, say Y. Only embedded should say N here. 1994 1995source "kernel/Kconfig.hz" 1996 1997config KEXEC 1998 bool "kexec system call" 1999 select KEXEC_CORE 2000 ---help--- 2001 kexec is a system call that implements the ability to shutdown your 2002 current kernel, and to start another kernel. It is like a reboot 2003 but it is independent of the system firmware. And like a reboot 2004 you can start any kernel with it, not just Linux. 2005 2006 The name comes from the similarity to the exec system call. 2007 2008 It is an ongoing process to be certain the hardware in a machine 2009 is properly shutdown, so do not be surprised if this code does not 2010 initially work for you. As of this writing the exact hardware 2011 interface is strongly in flux, so no good recommendation can be 2012 made. 2013 2014config KEXEC_FILE 2015 bool "kexec file based system call" 2016 select KEXEC_CORE 2017 select BUILD_BIN2C 2018 depends on X86_64 2019 depends on CRYPTO=y 2020 depends on CRYPTO_SHA256=y 2021 ---help--- 2022 This is new version of kexec system call. This system call is 2023 file based and takes file descriptors as system call argument 2024 for kernel and initramfs as opposed to list of segments as 2025 accepted by previous system call. 2026 2027config ARCH_HAS_KEXEC_PURGATORY 2028 def_bool KEXEC_FILE 2029 2030config KEXEC_SIG 2031 bool "Verify kernel signature during kexec_file_load() syscall" 2032 depends on KEXEC_FILE 2033 ---help--- 2034 2035 This option makes the kexec_file_load() syscall check for a valid 2036 signature of the kernel image. The image can still be loaded without 2037 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2038 there's a signature that we can check, then it must be valid. 2039 2040 In addition to this option, you need to enable signature 2041 verification for the corresponding kernel image type being 2042 loaded in order for this to work. 2043 2044config KEXEC_SIG_FORCE 2045 bool "Require a valid signature in kexec_file_load() syscall" 2046 depends on KEXEC_SIG 2047 ---help--- 2048 This option makes kernel signature verification mandatory for 2049 the kexec_file_load() syscall. 2050 2051config KEXEC_BZIMAGE_VERIFY_SIG 2052 bool "Enable bzImage signature verification support" 2053 depends on KEXEC_SIG 2054 depends on SIGNED_PE_FILE_VERIFICATION 2055 select SYSTEM_TRUSTED_KEYRING 2056 ---help--- 2057 Enable bzImage signature verification support. 2058 2059config CRASH_DUMP 2060 bool "kernel crash dumps" 2061 depends on X86_64 || (X86_32 && HIGHMEM) 2062 ---help--- 2063 Generate crash dump after being started by kexec. 2064 This should be normally only set in special crash dump kernels 2065 which are loaded in the main kernel with kexec-tools into 2066 a specially reserved region and then later executed after 2067 a crash by kdump/kexec. The crash dump kernel must be compiled 2068 to a memory address not used by the main kernel or BIOS using 2069 PHYSICAL_START, or it must be built as a relocatable image 2070 (CONFIG_RELOCATABLE=y). 2071 For more details see Documentation/admin-guide/kdump/kdump.rst 2072 2073config KEXEC_JUMP 2074 bool "kexec jump" 2075 depends on KEXEC && HIBERNATION 2076 ---help--- 2077 Jump between original kernel and kexeced kernel and invoke 2078 code in physical address mode via KEXEC 2079 2080config PHYSICAL_START 2081 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2082 default "0x1000000" 2083 ---help--- 2084 This gives the physical address where the kernel is loaded. 2085 2086 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2087 bzImage will decompress itself to above physical address and 2088 run from there. Otherwise, bzImage will run from the address where 2089 it has been loaded by the boot loader and will ignore above physical 2090 address. 2091 2092 In normal kdump cases one does not have to set/change this option 2093 as now bzImage can be compiled as a completely relocatable image 2094 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2095 address. This option is mainly useful for the folks who don't want 2096 to use a bzImage for capturing the crash dump and want to use a 2097 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2098 to be specifically compiled to run from a specific memory area 2099 (normally a reserved region) and this option comes handy. 2100 2101 So if you are using bzImage for capturing the crash dump, 2102 leave the value here unchanged to 0x1000000 and set 2103 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2104 for capturing the crash dump change this value to start of 2105 the reserved region. In other words, it can be set based on 2106 the "X" value as specified in the "crashkernel=YM@XM" 2107 command line boot parameter passed to the panic-ed 2108 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2109 for more details about crash dumps. 2110 2111 Usage of bzImage for capturing the crash dump is recommended as 2112 one does not have to build two kernels. Same kernel can be used 2113 as production kernel and capture kernel. Above option should have 2114 gone away after relocatable bzImage support is introduced. But it 2115 is present because there are users out there who continue to use 2116 vmlinux for dump capture. This option should go away down the 2117 line. 2118 2119 Don't change this unless you know what you are doing. 2120 2121config RELOCATABLE 2122 bool "Build a relocatable kernel" 2123 default y 2124 ---help--- 2125 This builds a kernel image that retains relocation information 2126 so it can be loaded someplace besides the default 1MB. 2127 The relocations tend to make the kernel binary about 10% larger, 2128 but are discarded at runtime. 2129 2130 One use is for the kexec on panic case where the recovery kernel 2131 must live at a different physical address than the primary 2132 kernel. 2133 2134 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2135 it has been loaded at and the compile time physical address 2136 (CONFIG_PHYSICAL_START) is used as the minimum location. 2137 2138config RANDOMIZE_BASE 2139 bool "Randomize the address of the kernel image (KASLR)" 2140 depends on RELOCATABLE 2141 default y 2142 ---help--- 2143 In support of Kernel Address Space Layout Randomization (KASLR), 2144 this randomizes the physical address at which the kernel image 2145 is decompressed and the virtual address where the kernel 2146 image is mapped, as a security feature that deters exploit 2147 attempts relying on knowledge of the location of kernel 2148 code internals. 2149 2150 On 64-bit, the kernel physical and virtual addresses are 2151 randomized separately. The physical address will be anywhere 2152 between 16MB and the top of physical memory (up to 64TB). The 2153 virtual address will be randomized from 16MB up to 1GB (9 bits 2154 of entropy). Note that this also reduces the memory space 2155 available to kernel modules from 1.5GB to 1GB. 2156 2157 On 32-bit, the kernel physical and virtual addresses are 2158 randomized together. They will be randomized from 16MB up to 2159 512MB (8 bits of entropy). 2160 2161 Entropy is generated using the RDRAND instruction if it is 2162 supported. If RDTSC is supported, its value is mixed into 2163 the entropy pool as well. If neither RDRAND nor RDTSC are 2164 supported, then entropy is read from the i8254 timer. The 2165 usable entropy is limited by the kernel being built using 2166 2GB addressing, and that PHYSICAL_ALIGN must be at a 2167 minimum of 2MB. As a result, only 10 bits of entropy are 2168 theoretically possible, but the implementations are further 2169 limited due to memory layouts. 2170 2171 If unsure, say Y. 2172 2173# Relocation on x86 needs some additional build support 2174config X86_NEED_RELOCS 2175 def_bool y 2176 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2177 2178config PHYSICAL_ALIGN 2179 hex "Alignment value to which kernel should be aligned" 2180 default "0x200000" 2181 range 0x2000 0x1000000 if X86_32 2182 range 0x200000 0x1000000 if X86_64 2183 ---help--- 2184 This value puts the alignment restrictions on physical address 2185 where kernel is loaded and run from. Kernel is compiled for an 2186 address which meets above alignment restriction. 2187 2188 If bootloader loads the kernel at a non-aligned address and 2189 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2190 address aligned to above value and run from there. 2191 2192 If bootloader loads the kernel at a non-aligned address and 2193 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2194 load address and decompress itself to the address it has been 2195 compiled for and run from there. The address for which kernel is 2196 compiled already meets above alignment restrictions. Hence the 2197 end result is that kernel runs from a physical address meeting 2198 above alignment restrictions. 2199 2200 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2201 this value must be a multiple of 0x200000. 2202 2203 Don't change this unless you know what you are doing. 2204 2205config DYNAMIC_MEMORY_LAYOUT 2206 bool 2207 ---help--- 2208 This option makes base addresses of vmalloc and vmemmap as well as 2209 __PAGE_OFFSET movable during boot. 2210 2211config RANDOMIZE_MEMORY 2212 bool "Randomize the kernel memory sections" 2213 depends on X86_64 2214 depends on RANDOMIZE_BASE 2215 select DYNAMIC_MEMORY_LAYOUT 2216 default RANDOMIZE_BASE 2217 ---help--- 2218 Randomizes the base virtual address of kernel memory sections 2219 (physical memory mapping, vmalloc & vmemmap). This security feature 2220 makes exploits relying on predictable memory locations less reliable. 2221 2222 The order of allocations remains unchanged. Entropy is generated in 2223 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2224 configuration have in average 30,000 different possible virtual 2225 addresses for each memory section. 2226 2227 If unsure, say Y. 2228 2229config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2230 hex "Physical memory mapping padding" if EXPERT 2231 depends on RANDOMIZE_MEMORY 2232 default "0xa" if MEMORY_HOTPLUG 2233 default "0x0" 2234 range 0x1 0x40 if MEMORY_HOTPLUG 2235 range 0x0 0x40 2236 ---help--- 2237 Define the padding in terabytes added to the existing physical 2238 memory size during kernel memory randomization. It is useful 2239 for memory hotplug support but reduces the entropy available for 2240 address randomization. 2241 2242 If unsure, leave at the default value. 2243 2244config HOTPLUG_CPU 2245 def_bool y 2246 depends on SMP 2247 2248config BOOTPARAM_HOTPLUG_CPU0 2249 bool "Set default setting of cpu0_hotpluggable" 2250 depends on HOTPLUG_CPU 2251 ---help--- 2252 Set whether default state of cpu0_hotpluggable is on or off. 2253 2254 Say Y here to enable CPU0 hotplug by default. If this switch 2255 is turned on, there is no need to give cpu0_hotplug kernel 2256 parameter and the CPU0 hotplug feature is enabled by default. 2257 2258 Please note: there are two known CPU0 dependencies if you want 2259 to enable the CPU0 hotplug feature either by this switch or by 2260 cpu0_hotplug kernel parameter. 2261 2262 First, resume from hibernate or suspend always starts from CPU0. 2263 So hibernate and suspend are prevented if CPU0 is offline. 2264 2265 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2266 offline if any interrupt can not migrate out of CPU0. There may 2267 be other CPU0 dependencies. 2268 2269 Please make sure the dependencies are under your control before 2270 you enable this feature. 2271 2272 Say N if you don't want to enable CPU0 hotplug feature by default. 2273 You still can enable the CPU0 hotplug feature at boot by kernel 2274 parameter cpu0_hotplug. 2275 2276config DEBUG_HOTPLUG_CPU0 2277 def_bool n 2278 prompt "Debug CPU0 hotplug" 2279 depends on HOTPLUG_CPU 2280 ---help--- 2281 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2282 soon as possible and boots up userspace with CPU0 offlined. User 2283 can online CPU0 back after boot time. 2284 2285 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2286 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2287 compilation or giving cpu0_hotplug kernel parameter at boot. 2288 2289 If unsure, say N. 2290 2291config COMPAT_VDSO 2292 def_bool n 2293 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2294 depends on COMPAT_32 2295 ---help--- 2296 Certain buggy versions of glibc will crash if they are 2297 presented with a 32-bit vDSO that is not mapped at the address 2298 indicated in its segment table. 2299 2300 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2301 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2302 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2303 the only released version with the bug, but OpenSUSE 9 2304 contains a buggy "glibc 2.3.2". 2305 2306 The symptom of the bug is that everything crashes on startup, saying: 2307 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2308 2309 Saying Y here changes the default value of the vdso32 boot 2310 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2311 This works around the glibc bug but hurts performance. 2312 2313 If unsure, say N: if you are compiling your own kernel, you 2314 are unlikely to be using a buggy version of glibc. 2315 2316choice 2317 prompt "vsyscall table for legacy applications" 2318 depends on X86_64 2319 default LEGACY_VSYSCALL_XONLY 2320 help 2321 Legacy user code that does not know how to find the vDSO expects 2322 to be able to issue three syscalls by calling fixed addresses in 2323 kernel space. Since this location is not randomized with ASLR, 2324 it can be used to assist security vulnerability exploitation. 2325 2326 This setting can be changed at boot time via the kernel command 2327 line parameter vsyscall=[emulate|xonly|none]. 2328 2329 On a system with recent enough glibc (2.14 or newer) and no 2330 static binaries, you can say None without a performance penalty 2331 to improve security. 2332 2333 If unsure, select "Emulate execution only". 2334 2335 config LEGACY_VSYSCALL_EMULATE 2336 bool "Full emulation" 2337 help 2338 The kernel traps and emulates calls into the fixed vsyscall 2339 address mapping. This makes the mapping non-executable, but 2340 it still contains readable known contents, which could be 2341 used in certain rare security vulnerability exploits. This 2342 configuration is recommended when using legacy userspace 2343 that still uses vsyscalls along with legacy binary 2344 instrumentation tools that require code to be readable. 2345 2346 An example of this type of legacy userspace is running 2347 Pin on an old binary that still uses vsyscalls. 2348 2349 config LEGACY_VSYSCALL_XONLY 2350 bool "Emulate execution only" 2351 help 2352 The kernel traps and emulates calls into the fixed vsyscall 2353 address mapping and does not allow reads. This 2354 configuration is recommended when userspace might use the 2355 legacy vsyscall area but support for legacy binary 2356 instrumentation of legacy code is not needed. It mitigates 2357 certain uses of the vsyscall area as an ASLR-bypassing 2358 buffer. 2359 2360 config LEGACY_VSYSCALL_NONE 2361 bool "None" 2362 help 2363 There will be no vsyscall mapping at all. This will 2364 eliminate any risk of ASLR bypass due to the vsyscall 2365 fixed address mapping. Attempts to use the vsyscalls 2366 will be reported to dmesg, so that either old or 2367 malicious userspace programs can be identified. 2368 2369endchoice 2370 2371config CMDLINE_BOOL 2372 bool "Built-in kernel command line" 2373 ---help--- 2374 Allow for specifying boot arguments to the kernel at 2375 build time. On some systems (e.g. embedded ones), it is 2376 necessary or convenient to provide some or all of the 2377 kernel boot arguments with the kernel itself (that is, 2378 to not rely on the boot loader to provide them.) 2379 2380 To compile command line arguments into the kernel, 2381 set this option to 'Y', then fill in the 2382 boot arguments in CONFIG_CMDLINE. 2383 2384 Systems with fully functional boot loaders (i.e. non-embedded) 2385 should leave this option set to 'N'. 2386 2387config CMDLINE 2388 string "Built-in kernel command string" 2389 depends on CMDLINE_BOOL 2390 default "" 2391 ---help--- 2392 Enter arguments here that should be compiled into the kernel 2393 image and used at boot time. If the boot loader provides a 2394 command line at boot time, it is appended to this string to 2395 form the full kernel command line, when the system boots. 2396 2397 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2398 change this behavior. 2399 2400 In most cases, the command line (whether built-in or provided 2401 by the boot loader) should specify the device for the root 2402 file system. 2403 2404config CMDLINE_OVERRIDE 2405 bool "Built-in command line overrides boot loader arguments" 2406 depends on CMDLINE_BOOL && CMDLINE != "" 2407 ---help--- 2408 Set this option to 'Y' to have the kernel ignore the boot loader 2409 command line, and use ONLY the built-in command line. 2410 2411 This is used to work around broken boot loaders. This should 2412 be set to 'N' under normal conditions. 2413 2414config MODIFY_LDT_SYSCALL 2415 bool "Enable the LDT (local descriptor table)" if EXPERT 2416 default y 2417 ---help--- 2418 Linux can allow user programs to install a per-process x86 2419 Local Descriptor Table (LDT) using the modify_ldt(2) system 2420 call. This is required to run 16-bit or segmented code such as 2421 DOSEMU or some Wine programs. It is also used by some very old 2422 threading libraries. 2423 2424 Enabling this feature adds a small amount of overhead to 2425 context switches and increases the low-level kernel attack 2426 surface. Disabling it removes the modify_ldt(2) system call. 2427 2428 Saying 'N' here may make sense for embedded or server kernels. 2429 2430source "kernel/livepatch/Kconfig" 2431 2432endmenu 2433 2434config ARCH_HAS_ADD_PAGES 2435 def_bool y 2436 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2437 2438config ARCH_ENABLE_MEMORY_HOTPLUG 2439 def_bool y 2440 depends on X86_64 || (X86_32 && HIGHMEM) 2441 2442config ARCH_ENABLE_MEMORY_HOTREMOVE 2443 def_bool y 2444 depends on MEMORY_HOTPLUG 2445 2446config USE_PERCPU_NUMA_NODE_ID 2447 def_bool y 2448 depends on NUMA 2449 2450config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2451 def_bool y 2452 depends on X86_64 || X86_PAE 2453 2454config ARCH_ENABLE_HUGEPAGE_MIGRATION 2455 def_bool y 2456 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2457 2458config ARCH_ENABLE_THP_MIGRATION 2459 def_bool y 2460 depends on X86_64 && TRANSPARENT_HUGEPAGE 2461 2462menu "Power management and ACPI options" 2463 2464config ARCH_HIBERNATION_HEADER 2465 def_bool y 2466 depends on HIBERNATION 2467 2468source "kernel/power/Kconfig" 2469 2470source "drivers/acpi/Kconfig" 2471 2472source "drivers/sfi/Kconfig" 2473 2474config X86_APM_BOOT 2475 def_bool y 2476 depends on APM 2477 2478menuconfig APM 2479 tristate "APM (Advanced Power Management) BIOS support" 2480 depends on X86_32 && PM_SLEEP 2481 ---help--- 2482 APM is a BIOS specification for saving power using several different 2483 techniques. This is mostly useful for battery powered laptops with 2484 APM compliant BIOSes. If you say Y here, the system time will be 2485 reset after a RESUME operation, the /proc/apm device will provide 2486 battery status information, and user-space programs will receive 2487 notification of APM "events" (e.g. battery status change). 2488 2489 If you select "Y" here, you can disable actual use of the APM 2490 BIOS by passing the "apm=off" option to the kernel at boot time. 2491 2492 Note that the APM support is almost completely disabled for 2493 machines with more than one CPU. 2494 2495 In order to use APM, you will need supporting software. For location 2496 and more information, read <file:Documentation/power/apm-acpi.rst> 2497 and the Battery Powered Linux mini-HOWTO, available from 2498 <http://www.tldp.org/docs.html#howto>. 2499 2500 This driver does not spin down disk drives (see the hdparm(8) 2501 manpage ("man 8 hdparm") for that), and it doesn't turn off 2502 VESA-compliant "green" monitors. 2503 2504 This driver does not support the TI 4000M TravelMate and the ACER 2505 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2506 desktop machines also don't have compliant BIOSes, and this driver 2507 may cause those machines to panic during the boot phase. 2508 2509 Generally, if you don't have a battery in your machine, there isn't 2510 much point in using this driver and you should say N. If you get 2511 random kernel OOPSes or reboots that don't seem to be related to 2512 anything, try disabling/enabling this option (or disabling/enabling 2513 APM in your BIOS). 2514 2515 Some other things you should try when experiencing seemingly random, 2516 "weird" problems: 2517 2518 1) make sure that you have enough swap space and that it is 2519 enabled. 2520 2) pass the "no-hlt" option to the kernel 2521 3) switch on floating point emulation in the kernel and pass 2522 the "no387" option to the kernel 2523 4) pass the "floppy=nodma" option to the kernel 2524 5) pass the "mem=4M" option to the kernel (thereby disabling 2525 all but the first 4 MB of RAM) 2526 6) make sure that the CPU is not over clocked. 2527 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2528 8) disable the cache from your BIOS settings 2529 9) install a fan for the video card or exchange video RAM 2530 10) install a better fan for the CPU 2531 11) exchange RAM chips 2532 12) exchange the motherboard. 2533 2534 To compile this driver as a module, choose M here: the 2535 module will be called apm. 2536 2537if APM 2538 2539config APM_IGNORE_USER_SUSPEND 2540 bool "Ignore USER SUSPEND" 2541 ---help--- 2542 This option will ignore USER SUSPEND requests. On machines with a 2543 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2544 series notebooks, it is necessary to say Y because of a BIOS bug. 2545 2546config APM_DO_ENABLE 2547 bool "Enable PM at boot time" 2548 ---help--- 2549 Enable APM features at boot time. From page 36 of the APM BIOS 2550 specification: "When disabled, the APM BIOS does not automatically 2551 power manage devices, enter the Standby State, enter the Suspend 2552 State, or take power saving steps in response to CPU Idle calls." 2553 This driver will make CPU Idle calls when Linux is idle (unless this 2554 feature is turned off -- see "Do CPU IDLE calls", below). This 2555 should always save battery power, but more complicated APM features 2556 will be dependent on your BIOS implementation. You may need to turn 2557 this option off if your computer hangs at boot time when using APM 2558 support, or if it beeps continuously instead of suspending. Turn 2559 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2560 T400CDT. This is off by default since most machines do fine without 2561 this feature. 2562 2563config APM_CPU_IDLE 2564 depends on CPU_IDLE 2565 bool "Make CPU Idle calls when idle" 2566 ---help--- 2567 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2568 On some machines, this can activate improved power savings, such as 2569 a slowed CPU clock rate, when the machine is idle. These idle calls 2570 are made after the idle loop has run for some length of time (e.g., 2571 333 mS). On some machines, this will cause a hang at boot time or 2572 whenever the CPU becomes idle. (On machines with more than one CPU, 2573 this option does nothing.) 2574 2575config APM_DISPLAY_BLANK 2576 bool "Enable console blanking using APM" 2577 ---help--- 2578 Enable console blanking using the APM. Some laptops can use this to 2579 turn off the LCD backlight when the screen blanker of the Linux 2580 virtual console blanks the screen. Note that this is only used by 2581 the virtual console screen blanker, and won't turn off the backlight 2582 when using the X Window system. This also doesn't have anything to 2583 do with your VESA-compliant power-saving monitor. Further, this 2584 option doesn't work for all laptops -- it might not turn off your 2585 backlight at all, or it might print a lot of errors to the console, 2586 especially if you are using gpm. 2587 2588config APM_ALLOW_INTS 2589 bool "Allow interrupts during APM BIOS calls" 2590 ---help--- 2591 Normally we disable external interrupts while we are making calls to 2592 the APM BIOS as a measure to lessen the effects of a badly behaving 2593 BIOS implementation. The BIOS should reenable interrupts if it 2594 needs to. Unfortunately, some BIOSes do not -- especially those in 2595 many of the newer IBM Thinkpads. If you experience hangs when you 2596 suspend, try setting this to Y. Otherwise, say N. 2597 2598endif # APM 2599 2600source "drivers/cpufreq/Kconfig" 2601 2602source "drivers/cpuidle/Kconfig" 2603 2604source "drivers/idle/Kconfig" 2605 2606endmenu 2607 2608 2609menu "Bus options (PCI etc.)" 2610 2611choice 2612 prompt "PCI access mode" 2613 depends on X86_32 && PCI 2614 default PCI_GOANY 2615 ---help--- 2616 On PCI systems, the BIOS can be used to detect the PCI devices and 2617 determine their configuration. However, some old PCI motherboards 2618 have BIOS bugs and may crash if this is done. Also, some embedded 2619 PCI-based systems don't have any BIOS at all. Linux can also try to 2620 detect the PCI hardware directly without using the BIOS. 2621 2622 With this option, you can specify how Linux should detect the 2623 PCI devices. If you choose "BIOS", the BIOS will be used, 2624 if you choose "Direct", the BIOS won't be used, and if you 2625 choose "MMConfig", then PCI Express MMCONFIG will be used. 2626 If you choose "Any", the kernel will try MMCONFIG, then the 2627 direct access method and falls back to the BIOS if that doesn't 2628 work. If unsure, go with the default, which is "Any". 2629 2630config PCI_GOBIOS 2631 bool "BIOS" 2632 2633config PCI_GOMMCONFIG 2634 bool "MMConfig" 2635 2636config PCI_GODIRECT 2637 bool "Direct" 2638 2639config PCI_GOOLPC 2640 bool "OLPC XO-1" 2641 depends on OLPC 2642 2643config PCI_GOANY 2644 bool "Any" 2645 2646endchoice 2647 2648config PCI_BIOS 2649 def_bool y 2650 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2651 2652# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2653config PCI_DIRECT 2654 def_bool y 2655 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2656 2657config PCI_MMCONFIG 2658 bool "Support mmconfig PCI config space access" if X86_64 2659 default y 2660 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2661 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2662 2663config PCI_OLPC 2664 def_bool y 2665 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2666 2667config PCI_XEN 2668 def_bool y 2669 depends on PCI && XEN 2670 select SWIOTLB_XEN 2671 2672config MMCONF_FAM10H 2673 def_bool y 2674 depends on X86_64 && PCI_MMCONFIG && ACPI 2675 2676config PCI_CNB20LE_QUIRK 2677 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2678 depends on PCI 2679 help 2680 Read the PCI windows out of the CNB20LE host bridge. This allows 2681 PCI hotplug to work on systems with the CNB20LE chipset which do 2682 not have ACPI. 2683 2684 There's no public spec for this chipset, and this functionality 2685 is known to be incomplete. 2686 2687 You should say N unless you know you need this. 2688 2689config ISA_BUS 2690 bool "ISA bus support on modern systems" if EXPERT 2691 help 2692 Expose ISA bus device drivers and options available for selection and 2693 configuration. Enable this option if your target machine has an ISA 2694 bus. ISA is an older system, displaced by PCI and newer bus 2695 architectures -- if your target machine is modern, it probably does 2696 not have an ISA bus. 2697 2698 If unsure, say N. 2699 2700# x86_64 have no ISA slots, but can have ISA-style DMA. 2701config ISA_DMA_API 2702 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2703 default y 2704 help 2705 Enables ISA-style DMA support for devices requiring such controllers. 2706 If unsure, say Y. 2707 2708if X86_32 2709 2710config ISA 2711 bool "ISA support" 2712 ---help--- 2713 Find out whether you have ISA slots on your motherboard. ISA is the 2714 name of a bus system, i.e. the way the CPU talks to the other stuff 2715 inside your box. Other bus systems are PCI, EISA, MicroChannel 2716 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2717 newer boards don't support it. If you have ISA, say Y, otherwise N. 2718 2719config SCx200 2720 tristate "NatSemi SCx200 support" 2721 ---help--- 2722 This provides basic support for National Semiconductor's 2723 (now AMD's) Geode processors. The driver probes for the 2724 PCI-IDs of several on-chip devices, so its a good dependency 2725 for other scx200_* drivers. 2726 2727 If compiled as a module, the driver is named scx200. 2728 2729config SCx200HR_TIMER 2730 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2731 depends on SCx200 2732 default y 2733 ---help--- 2734 This driver provides a clocksource built upon the on-chip 2735 27MHz high-resolution timer. Its also a workaround for 2736 NSC Geode SC-1100's buggy TSC, which loses time when the 2737 processor goes idle (as is done by the scheduler). The 2738 other workaround is idle=poll boot option. 2739 2740config OLPC 2741 bool "One Laptop Per Child support" 2742 depends on !X86_PAE 2743 select GPIOLIB 2744 select OF 2745 select OF_PROMTREE 2746 select IRQ_DOMAIN 2747 select OLPC_EC 2748 ---help--- 2749 Add support for detecting the unique features of the OLPC 2750 XO hardware. 2751 2752config OLPC_XO1_PM 2753 bool "OLPC XO-1 Power Management" 2754 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2755 ---help--- 2756 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2757 2758config OLPC_XO1_RTC 2759 bool "OLPC XO-1 Real Time Clock" 2760 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2761 ---help--- 2762 Add support for the XO-1 real time clock, which can be used as a 2763 programmable wakeup source. 2764 2765config OLPC_XO1_SCI 2766 bool "OLPC XO-1 SCI extras" 2767 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2768 depends on INPUT=y 2769 select POWER_SUPPLY 2770 ---help--- 2771 Add support for SCI-based features of the OLPC XO-1 laptop: 2772 - EC-driven system wakeups 2773 - Power button 2774 - Ebook switch 2775 - Lid switch 2776 - AC adapter status updates 2777 - Battery status updates 2778 2779config OLPC_XO15_SCI 2780 bool "OLPC XO-1.5 SCI extras" 2781 depends on OLPC && ACPI 2782 select POWER_SUPPLY 2783 ---help--- 2784 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2785 - EC-driven system wakeups 2786 - AC adapter status updates 2787 - Battery status updates 2788 2789config ALIX 2790 bool "PCEngines ALIX System Support (LED setup)" 2791 select GPIOLIB 2792 ---help--- 2793 This option enables system support for the PCEngines ALIX. 2794 At present this just sets up LEDs for GPIO control on 2795 ALIX2/3/6 boards. However, other system specific setup should 2796 get added here. 2797 2798 Note: You must still enable the drivers for GPIO and LED support 2799 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2800 2801 Note: You have to set alix.force=1 for boards with Award BIOS. 2802 2803config NET5501 2804 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2805 select GPIOLIB 2806 ---help--- 2807 This option enables system support for the Soekris Engineering net5501. 2808 2809config GEOS 2810 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2811 select GPIOLIB 2812 depends on DMI 2813 ---help--- 2814 This option enables system support for the Traverse Technologies GEOS. 2815 2816config TS5500 2817 bool "Technologic Systems TS-5500 platform support" 2818 depends on MELAN 2819 select CHECK_SIGNATURE 2820 select NEW_LEDS 2821 select LEDS_CLASS 2822 ---help--- 2823 This option enables system support for the Technologic Systems TS-5500. 2824 2825endif # X86_32 2826 2827config AMD_NB 2828 def_bool y 2829 depends on CPU_SUP_AMD && PCI 2830 2831config X86_SYSFB 2832 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2833 help 2834 Firmwares often provide initial graphics framebuffers so the BIOS, 2835 bootloader or kernel can show basic video-output during boot for 2836 user-guidance and debugging. Historically, x86 used the VESA BIOS 2837 Extensions and EFI-framebuffers for this, which are mostly limited 2838 to x86. 2839 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2840 framebuffers so the new generic system-framebuffer drivers can be 2841 used on x86. If the framebuffer is not compatible with the generic 2842 modes, it is advertised as fallback platform framebuffer so legacy 2843 drivers like efifb, vesafb and uvesafb can pick it up. 2844 If this option is not selected, all system framebuffers are always 2845 marked as fallback platform framebuffers as usual. 2846 2847 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2848 not be able to pick up generic system framebuffers if this option 2849 is selected. You are highly encouraged to enable simplefb as 2850 replacement if you select this option. simplefb can correctly deal 2851 with generic system framebuffers. But you should still keep vesafb 2852 and others enabled as fallback if a system framebuffer is 2853 incompatible with simplefb. 2854 2855 If unsure, say Y. 2856 2857endmenu 2858 2859 2860menu "Binary Emulations" 2861 2862config IA32_EMULATION 2863 bool "IA32 Emulation" 2864 depends on X86_64 2865 select ARCH_WANT_OLD_COMPAT_IPC 2866 select BINFMT_ELF 2867 select COMPAT_BINFMT_ELF 2868 select COMPAT_OLD_SIGACTION 2869 ---help--- 2870 Include code to run legacy 32-bit programs under a 2871 64-bit kernel. You should likely turn this on, unless you're 2872 100% sure that you don't have any 32-bit programs left. 2873 2874config IA32_AOUT 2875 tristate "IA32 a.out support" 2876 depends on IA32_EMULATION 2877 depends on BROKEN 2878 ---help--- 2879 Support old a.out binaries in the 32bit emulation. 2880 2881config X86_X32 2882 bool "x32 ABI for 64-bit mode" 2883 depends on X86_64 2884 ---help--- 2885 Include code to run binaries for the x32 native 32-bit ABI 2886 for 64-bit processors. An x32 process gets access to the 2887 full 64-bit register file and wide data path while leaving 2888 pointers at 32 bits for smaller memory footprint. 2889 2890 You will need a recent binutils (2.22 or later) with 2891 elf32_x86_64 support enabled to compile a kernel with this 2892 option set. 2893 2894config COMPAT_32 2895 def_bool y 2896 depends on IA32_EMULATION || X86_32 2897 select HAVE_UID16 2898 select OLD_SIGSUSPEND3 2899 2900config COMPAT 2901 def_bool y 2902 depends on IA32_EMULATION || X86_X32 2903 2904if COMPAT 2905config COMPAT_FOR_U64_ALIGNMENT 2906 def_bool y 2907 2908config SYSVIPC_COMPAT 2909 def_bool y 2910 depends on SYSVIPC 2911endif 2912 2913endmenu 2914 2915 2916config HAVE_ATOMIC_IOMAP 2917 def_bool y 2918 depends on X86_32 2919 2920source "drivers/firmware/Kconfig" 2921 2922source "arch/x86/kvm/Kconfig" 2923 2924source "arch/x86/Kconfig.assembler" 2925