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 select ARCH_SPLIT_ARG64 22 23config X86_64 24 def_bool y 25 depends on 64BIT 26 # Options that are inherently 64-bit kernel only: 27 select ARCH_HAS_GIGANTIC_PAGE 28 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 29 select ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT 30 select ARCH_USE_CMPXCHG_LOCKREF 31 select HAVE_ARCH_SOFT_DIRTY 32 select MODULES_USE_ELF_RELA 33 select NEED_DMA_MAP_STATE 34 select SWIOTLB 35 36config FORCE_DYNAMIC_FTRACE 37 def_bool y 38 depends on X86_32 39 depends on FUNCTION_TRACER 40 select DYNAMIC_FTRACE 41 help 42 We keep the static function tracing (!DYNAMIC_FTRACE) around 43 in order to test the non static function tracing in the 44 generic code, as other architectures still use it. But we 45 only need to keep it around for x86_64. No need to keep it 46 for x86_32. For x86_32, force DYNAMIC_FTRACE. 47# 48# Arch settings 49# 50# ( Note that options that are marked 'if X86_64' could in principle be 51# ported to 32-bit as well. ) 52# 53config X86 54 def_bool y 55 # 56 # Note: keep this list sorted alphabetically 57 # 58 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 59 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 60 select ARCH_32BIT_OFF_T if X86_32 61 select ARCH_CLOCKSOURCE_INIT 62 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 63 select ARCH_HAS_CPU_FINALIZE_INIT 64 select ARCH_HAS_DEBUG_VIRTUAL 65 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 66 select ARCH_HAS_DEVMEM_IS_ALLOWED 67 select ARCH_HAS_EARLY_DEBUG if KGDB 68 select ARCH_HAS_ELF_RANDOMIZE 69 select ARCH_HAS_FAST_MULTIPLIER 70 select ARCH_HAS_FILTER_PGPROT 71 select ARCH_HAS_FORTIFY_SOURCE 72 select ARCH_HAS_GCOV_PROFILE_ALL 73 select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION 74 select ARCH_HAS_MEM_ENCRYPT 75 select ARCH_HAS_MEMBARRIER_SYNC_CORE 76 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 77 select ARCH_HAS_PMEM_API if X86_64 78 select ARCH_HAS_PTE_DEVMAP if X86_64 79 select ARCH_HAS_PTE_SPECIAL 80 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 81 select ARCH_HAS_COPY_MC if X86_64 82 select ARCH_HAS_SET_MEMORY 83 select ARCH_HAS_SET_DIRECT_MAP 84 select ARCH_HAS_STRICT_KERNEL_RWX 85 select ARCH_HAS_STRICT_MODULE_RWX 86 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 87 select ARCH_HAS_SYSCALL_WRAPPER 88 select ARCH_HAS_UBSAN_SANITIZE_ALL 89 select ARCH_HAS_DEBUG_WX 90 select ARCH_HAVE_NMI_SAFE_CMPXCHG 91 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 92 select ARCH_MIGHT_HAVE_PC_PARPORT 93 select ARCH_MIGHT_HAVE_PC_SERIO 94 select ARCH_STACKWALK 95 select ARCH_SUPPORTS_ACPI 96 select ARCH_SUPPORTS_ATOMIC_RMW 97 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 98 select ARCH_SUPPORTS_LTO_CLANG if X86_64 99 select ARCH_SUPPORTS_LTO_CLANG_THIN if X86_64 100 select ARCH_USE_BUILTIN_BSWAP 101 select ARCH_USE_QUEUED_RWLOCKS 102 select ARCH_USE_QUEUED_SPINLOCKS 103 select ARCH_USE_SYM_ANNOTATIONS 104 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 105 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 106 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 107 select ARCH_WANT_HUGE_PMD_SHARE 108 select ARCH_WANT_LD_ORPHAN_WARN 109 select ARCH_WANTS_THP_SWAP if X86_64 110 select BUILDTIME_TABLE_SORT 111 select CLKEVT_I8253 112 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 113 select CLOCKSOURCE_WATCHDOG 114 select DCACHE_WORD_ACCESS 115 select EDAC_ATOMIC_SCRUB 116 select EDAC_SUPPORT 117 select GENERIC_CLOCKEVENTS 118 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 119 select GENERIC_CLOCKEVENTS_MIN_ADJUST 120 select GENERIC_CMOS_UPDATE 121 select GENERIC_CPU_AUTOPROBE 122 select GENERIC_CPU_VULNERABILITIES 123 select GENERIC_EARLY_IOREMAP 124 select GENERIC_ENTRY 125 select GENERIC_FIND_FIRST_BIT 126 select GENERIC_IOMAP 127 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 128 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 129 select GENERIC_IRQ_MIGRATION if SMP 130 select GENERIC_IRQ_PROBE 131 select GENERIC_IRQ_RESERVATION_MODE 132 select GENERIC_IRQ_SHOW 133 select GENERIC_PENDING_IRQ if SMP 134 select GENERIC_PTDUMP 135 select GENERIC_SMP_IDLE_THREAD 136 select GENERIC_STRNCPY_FROM_USER 137 select GENERIC_STRNLEN_USER 138 select GENERIC_TIME_VSYSCALL 139 select GENERIC_GETTIMEOFDAY 140 select GENERIC_VDSO_TIME_NS 141 select GUP_GET_PTE_LOW_HIGH if X86_PAE 142 select HARDIRQS_SW_RESEND 143 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 144 select HAVE_ACPI_APEI if ACPI 145 select HAVE_ACPI_APEI_NMI if ACPI 146 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 147 select HAVE_ARCH_AUDITSYSCALL 148 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 149 select HAVE_ARCH_JUMP_LABEL 150 select HAVE_ARCH_JUMP_LABEL_RELATIVE 151 select HAVE_ARCH_KASAN if X86_64 152 select HAVE_ARCH_KASAN_VMALLOC if X86_64 153 select HAVE_ARCH_KFENCE 154 select HAVE_ARCH_KGDB 155 select HAVE_ARCH_MMAP_RND_BITS if MMU 156 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 157 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 158 select HAVE_ARCH_PREL32_RELOCATIONS 159 select HAVE_ARCH_SECCOMP_FILTER 160 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 161 select HAVE_ARCH_STACKLEAK 162 select HAVE_ARCH_TRACEHOOK 163 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 164 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 165 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 166 select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 167 select HAVE_ARCH_VMAP_STACK if X86_64 168 select HAVE_ARCH_WITHIN_STACK_FRAMES 169 select HAVE_ASM_MODVERSIONS 170 select HAVE_CMPXCHG_DOUBLE 171 select HAVE_CMPXCHG_LOCAL 172 select HAVE_CONTEXT_TRACKING if X86_64 173 select HAVE_C_RECORDMCOUNT 174 select HAVE_OBJTOOL_MCOUNT if STACK_VALIDATION 175 select HAVE_DEBUG_KMEMLEAK 176 select HAVE_DMA_CONTIGUOUS 177 select HAVE_DYNAMIC_FTRACE 178 select HAVE_DYNAMIC_FTRACE_WITH_REGS 179 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 180 select HAVE_EBPF_JIT 181 select HAVE_EFFICIENT_UNALIGNED_ACCESS 182 select HAVE_EISA 183 select HAVE_EXIT_THREAD 184 select HAVE_FAST_GUP 185 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 186 select HAVE_FTRACE_MCOUNT_RECORD 187 select HAVE_FUNCTION_GRAPH_TRACER 188 select HAVE_FUNCTION_TRACER 189 select HAVE_GCC_PLUGINS 190 select HAVE_HW_BREAKPOINT 191 select HAVE_IDE 192 select HAVE_IOREMAP_PROT 193 select HAVE_IRQ_TIME_ACCOUNTING 194 select HAVE_KERNEL_BZIP2 195 select HAVE_KERNEL_GZIP 196 select HAVE_KERNEL_LZ4 197 select HAVE_KERNEL_LZMA 198 select HAVE_KERNEL_LZO 199 select HAVE_KERNEL_XZ 200 select HAVE_KERNEL_ZSTD 201 select HAVE_KPROBES 202 select HAVE_KPROBES_ON_FTRACE 203 select HAVE_FUNCTION_ERROR_INJECTION 204 select HAVE_KRETPROBES 205 select HAVE_KVM 206 select HAVE_LIVEPATCH if X86_64 207 select HAVE_MIXED_BREAKPOINTS_REGS 208 select HAVE_MOD_ARCH_SPECIFIC 209 select HAVE_MOVE_PMD 210 select HAVE_MOVE_PUD 211 select HAVE_NMI 212 select HAVE_OPROFILE 213 select HAVE_OPTPROBES 214 select HAVE_PCSPKR_PLATFORM 215 select HAVE_PERF_EVENTS 216 select HAVE_PERF_EVENTS_NMI 217 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 218 select HAVE_PCI 219 select HAVE_PERF_REGS 220 select HAVE_PERF_USER_STACK_DUMP 221 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 222 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 223 select HAVE_REGS_AND_STACK_ACCESS_API 224 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 225 select HAVE_FUNCTION_ARG_ACCESS_API 226 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 227 select HAVE_STACK_VALIDATION if X86_64 228 select HAVE_STATIC_CALL 229 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION 230 select HAVE_RSEQ 231 select HAVE_SYSCALL_TRACEPOINTS 232 select HAVE_UNSTABLE_SCHED_CLOCK 233 select HAVE_USER_RETURN_NOTIFIER 234 select HAVE_GENERIC_VDSO 235 select HOTPLUG_SMT if SMP 236 select IRQ_FORCED_THREADING 237 select NEED_SG_DMA_LENGTH 238 select PCI_DOMAINS if PCI 239 select PCI_LOCKLESS_CONFIG if PCI 240 select PERF_EVENTS 241 select RTC_LIB 242 select RTC_MC146818_LIB 243 select SPARSE_IRQ 244 select SRCU 245 select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE) 246 select SYSCTL_EXCEPTION_TRACE 247 select THREAD_INFO_IN_TASK 248 select USER_STACKTRACE_SUPPORT 249 select VIRT_TO_BUS 250 select HAVE_ARCH_KCSAN if X86_64 251 select X86_FEATURE_NAMES if PROC_FS 252 select PROC_PID_ARCH_STATUS if PROC_FS 253 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 254 255config INSTRUCTION_DECODER 256 def_bool y 257 depends on KPROBES || PERF_EVENTS || UPROBES 258 259config OUTPUT_FORMAT 260 string 261 default "elf32-i386" if X86_32 262 default "elf64-x86-64" if X86_64 263 264config LOCKDEP_SUPPORT 265 def_bool y 266 267config STACKTRACE_SUPPORT 268 def_bool y 269 270config MMU 271 def_bool y 272 273config ARCH_MMAP_RND_BITS_MIN 274 default 28 if 64BIT 275 default 8 276 277config ARCH_MMAP_RND_BITS_MAX 278 default 32 if 64BIT 279 default 16 280 281config ARCH_MMAP_RND_COMPAT_BITS_MIN 282 default 8 283 284config ARCH_MMAP_RND_COMPAT_BITS_MAX 285 default 16 286 287config SBUS 288 bool 289 290config GENERIC_ISA_DMA 291 def_bool y 292 depends on ISA_DMA_API 293 294config GENERIC_BUG 295 def_bool y 296 depends on BUG 297 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 298 299config GENERIC_BUG_RELATIVE_POINTERS 300 bool 301 302config ARCH_MAY_HAVE_PC_FDC 303 def_bool y 304 depends on ISA_DMA_API 305 306config GENERIC_CALIBRATE_DELAY 307 def_bool y 308 309config ARCH_HAS_CPU_RELAX 310 def_bool y 311 312config ARCH_HAS_CACHE_LINE_SIZE 313 def_bool y 314 315config ARCH_HAS_FILTER_PGPROT 316 def_bool y 317 318config HAVE_SETUP_PER_CPU_AREA 319 def_bool y 320 321config NEED_PER_CPU_EMBED_FIRST_CHUNK 322 def_bool y 323 324config NEED_PER_CPU_PAGE_FIRST_CHUNK 325 def_bool y 326 327config ARCH_HIBERNATION_POSSIBLE 328 def_bool y 329 330config ARCH_SUSPEND_POSSIBLE 331 def_bool y 332 333config ARCH_WANT_GENERAL_HUGETLB 334 def_bool y 335 336config ZONE_DMA32 337 def_bool y if X86_64 338 339config AUDIT_ARCH 340 def_bool y if X86_64 341 342config ARCH_SUPPORTS_DEBUG_PAGEALLOC 343 def_bool y 344 345config KASAN_SHADOW_OFFSET 346 hex 347 depends on KASAN 348 default 0xdffffc0000000000 349 350config HAVE_INTEL_TXT 351 def_bool y 352 depends on INTEL_IOMMU && ACPI 353 354config X86_32_SMP 355 def_bool y 356 depends on X86_32 && SMP 357 358config X86_64_SMP 359 def_bool y 360 depends on X86_64 && SMP 361 362config X86_32_LAZY_GS 363 def_bool y 364 depends on X86_32 && !STACKPROTECTOR 365 366config ARCH_SUPPORTS_UPROBES 367 def_bool y 368 369config FIX_EARLYCON_MEM 370 def_bool y 371 372config DYNAMIC_PHYSICAL_MASK 373 bool 374 375config PGTABLE_LEVELS 376 int 377 default 5 if X86_5LEVEL 378 default 4 if X86_64 379 default 3 if X86_PAE 380 default 2 381 382config CC_HAS_SANE_STACKPROTECTOR 383 bool 384 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 385 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 386 help 387 We have to make sure stack protector is unconditionally disabled if 388 the compiler produces broken code. 389 390menu "Processor type and features" 391 392config ZONE_DMA 393 bool "DMA memory allocation support" if EXPERT 394 default y 395 help 396 DMA memory allocation support allows devices with less than 32-bit 397 addressing to allocate within the first 16MB of address space. 398 Disable if no such devices will be used. 399 400 If unsure, say Y. 401 402config SMP 403 bool "Symmetric multi-processing support" 404 help 405 This enables support for systems with more than one CPU. If you have 406 a system with only one CPU, say N. If you have a system with more 407 than one CPU, say Y. 408 409 If you say N here, the kernel will run on uni- and multiprocessor 410 machines, but will use only one CPU of a multiprocessor machine. If 411 you say Y here, the kernel will run on many, but not all, 412 uniprocessor machines. On a uniprocessor machine, the kernel 413 will run faster if you say N here. 414 415 Note that if you say Y here and choose architecture "586" or 416 "Pentium" under "Processor family", the kernel will not work on 486 417 architectures. Similarly, multiprocessor kernels for the "PPro" 418 architecture may not work on all Pentium based boards. 419 420 People using multiprocessor machines who say Y here should also say 421 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 422 Management" code will be disabled if you say Y here. 423 424 See also <file:Documentation/x86/i386/IO-APIC.rst>, 425 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 426 <http://www.tldp.org/docs.html#howto>. 427 428 If you don't know what to do here, say N. 429 430config X86_FEATURE_NAMES 431 bool "Processor feature human-readable names" if EMBEDDED 432 default y 433 help 434 This option compiles in a table of x86 feature bits and corresponding 435 names. This is required to support /proc/cpuinfo and a few kernel 436 messages. You can disable this to save space, at the expense of 437 making those few kernel messages show numeric feature bits instead. 438 439 If in doubt, say Y. 440 441config X86_X2APIC 442 bool "Support x2apic" 443 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 444 help 445 This enables x2apic support on CPUs that have this feature. 446 447 This allows 32-bit apic IDs (so it can support very large systems), 448 and accesses the local apic via MSRs not via mmio. 449 450 If you don't know what to do here, say N. 451 452config X86_MPPARSE 453 bool "Enable MPS table" if ACPI || SFI 454 default y 455 depends on X86_LOCAL_APIC 456 help 457 For old smp systems that do not have proper acpi support. Newer systems 458 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 459 460config GOLDFISH 461 def_bool y 462 depends on X86_GOLDFISH 463 464config X86_CPU_RESCTRL 465 bool "x86 CPU resource control support" 466 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 467 select KERNFS 468 select PROC_CPU_RESCTRL if PROC_FS 469 help 470 Enable x86 CPU resource control support. 471 472 Provide support for the allocation and monitoring of system resources 473 usage by the CPU. 474 475 Intel calls this Intel Resource Director Technology 476 (Intel(R) RDT). More information about RDT can be found in the 477 Intel x86 Architecture Software Developer Manual. 478 479 AMD calls this AMD Platform Quality of Service (AMD QoS). 480 More information about AMD QoS can be found in the AMD64 Technology 481 Platform Quality of Service Extensions manual. 482 483 Say N if unsure. 484 485if X86_32 486config X86_BIGSMP 487 bool "Support for big SMP systems with more than 8 CPUs" 488 depends on SMP 489 help 490 This option is needed for the systems that have more than 8 CPUs. 491 492config X86_EXTENDED_PLATFORM 493 bool "Support for extended (non-PC) x86 platforms" 494 default y 495 help 496 If you disable this option then the kernel will only support 497 standard PC platforms. (which covers the vast majority of 498 systems out there.) 499 500 If you enable this option then you'll be able to select support 501 for the following (non-PC) 32 bit x86 platforms: 502 Goldfish (Android emulator) 503 AMD Elan 504 RDC R-321x SoC 505 SGI 320/540 (Visual Workstation) 506 STA2X11-based (e.g. Northville) 507 Moorestown MID devices 508 509 If you have one of these systems, or if you want to build a 510 generic distribution kernel, say Y here - otherwise say N. 511endif 512 513if X86_64 514config X86_EXTENDED_PLATFORM 515 bool "Support for extended (non-PC) x86 platforms" 516 default y 517 help 518 If you disable this option then the kernel will only support 519 standard PC platforms. (which covers the vast majority of 520 systems out there.) 521 522 If you enable this option then you'll be able to select support 523 for the following (non-PC) 64 bit x86 platforms: 524 Numascale NumaChip 525 ScaleMP vSMP 526 SGI Ultraviolet 527 528 If you have one of these systems, or if you want to build a 529 generic distribution kernel, say Y here - otherwise say N. 530endif 531# This is an alphabetically sorted list of 64 bit extended platforms 532# Please maintain the alphabetic order if and when there are additions 533config X86_NUMACHIP 534 bool "Numascale NumaChip" 535 depends on X86_64 536 depends on X86_EXTENDED_PLATFORM 537 depends on NUMA 538 depends on SMP 539 depends on X86_X2APIC 540 depends on PCI_MMCONFIG 541 help 542 Adds support for Numascale NumaChip large-SMP systems. Needed to 543 enable more than ~168 cores. 544 If you don't have one of these, you should say N here. 545 546config X86_VSMP 547 bool "ScaleMP vSMP" 548 select HYPERVISOR_GUEST 549 select PARAVIRT 550 depends on X86_64 && PCI 551 depends on X86_EXTENDED_PLATFORM 552 depends on SMP 553 help 554 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 555 supposed to run on these EM64T-based machines. Only choose this option 556 if you have one of these machines. 557 558config X86_UV 559 bool "SGI Ultraviolet" 560 depends on X86_64 561 depends on X86_EXTENDED_PLATFORM 562 depends on NUMA 563 depends on EFI 564 depends on KEXEC_CORE 565 depends on X86_X2APIC 566 depends on PCI 567 help 568 This option is needed in order to support SGI Ultraviolet systems. 569 If you don't have one of these, you should say N here. 570 571# Following is an alphabetically sorted list of 32 bit extended platforms 572# Please maintain the alphabetic order if and when there are additions 573 574config X86_GOLDFISH 575 bool "Goldfish (Virtual Platform)" 576 depends on X86_EXTENDED_PLATFORM 577 help 578 Enable support for the Goldfish virtual platform used primarily 579 for Android development. Unless you are building for the Android 580 Goldfish emulator say N here. 581 582config X86_INTEL_CE 583 bool "CE4100 TV platform" 584 depends on PCI 585 depends on PCI_GODIRECT 586 depends on X86_IO_APIC 587 depends on X86_32 588 depends on X86_EXTENDED_PLATFORM 589 select X86_REBOOTFIXUPS 590 select OF 591 select OF_EARLY_FLATTREE 592 help 593 Select for the Intel CE media processor (CE4100) SOC. 594 This option compiles in support for the CE4100 SOC for settop 595 boxes and media devices. 596 597config X86_INTEL_MID 598 bool "Intel MID platform support" 599 depends on X86_EXTENDED_PLATFORM 600 depends on X86_PLATFORM_DEVICES 601 depends on PCI 602 depends on X86_64 || (PCI_GOANY && X86_32) 603 depends on X86_IO_APIC 604 select SFI 605 select I2C 606 select DW_APB_TIMER 607 select APB_TIMER 608 select INTEL_SCU_PCI 609 select MFD_INTEL_MSIC 610 help 611 Select to build a kernel capable of supporting Intel MID (Mobile 612 Internet Device) platform systems which do not have the PCI legacy 613 interfaces. If you are building for a PC class system say N here. 614 615 Intel MID platforms are based on an Intel processor and chipset which 616 consume less power than most of the x86 derivatives. 617 618config X86_INTEL_QUARK 619 bool "Intel Quark platform support" 620 depends on X86_32 621 depends on X86_EXTENDED_PLATFORM 622 depends on X86_PLATFORM_DEVICES 623 depends on X86_TSC 624 depends on PCI 625 depends on PCI_GOANY 626 depends on X86_IO_APIC 627 select IOSF_MBI 628 select INTEL_IMR 629 select COMMON_CLK 630 help 631 Select to include support for Quark X1000 SoC. 632 Say Y here if you have a Quark based system such as the Arduino 633 compatible Intel Galileo. 634 635config X86_INTEL_LPSS 636 bool "Intel Low Power Subsystem Support" 637 depends on X86 && ACPI && PCI 638 select COMMON_CLK 639 select PINCTRL 640 select IOSF_MBI 641 help 642 Select to build support for Intel Low Power Subsystem such as 643 found on Intel Lynxpoint PCH. Selecting this option enables 644 things like clock tree (common clock framework) and pincontrol 645 which are needed by the LPSS peripheral drivers. 646 647config X86_AMD_PLATFORM_DEVICE 648 bool "AMD ACPI2Platform devices support" 649 depends on ACPI 650 select COMMON_CLK 651 select PINCTRL 652 help 653 Select to interpret AMD specific ACPI device to platform device 654 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 655 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 656 implemented under PINCTRL subsystem. 657 658config IOSF_MBI 659 tristate "Intel SoC IOSF Sideband support for SoC platforms" 660 depends on PCI 661 help 662 This option enables sideband register access support for Intel SoC 663 platforms. On these platforms the IOSF sideband is used in lieu of 664 MSR's for some register accesses, mostly but not limited to thermal 665 and power. Drivers may query the availability of this device to 666 determine if they need the sideband in order to work on these 667 platforms. The sideband is available on the following SoC products. 668 This list is not meant to be exclusive. 669 - BayTrail 670 - Braswell 671 - Quark 672 673 You should say Y if you are running a kernel on one of these SoC's. 674 675config IOSF_MBI_DEBUG 676 bool "Enable IOSF sideband access through debugfs" 677 depends on IOSF_MBI && DEBUG_FS 678 help 679 Select this option to expose the IOSF sideband access registers (MCR, 680 MDR, MCRX) through debugfs to write and read register information from 681 different units on the SoC. This is most useful for obtaining device 682 state information for debug and analysis. As this is a general access 683 mechanism, users of this option would have specific knowledge of the 684 device they want to access. 685 686 If you don't require the option or are in doubt, say N. 687 688config X86_RDC321X 689 bool "RDC R-321x SoC" 690 depends on X86_32 691 depends on X86_EXTENDED_PLATFORM 692 select M486 693 select X86_REBOOTFIXUPS 694 help 695 This option is needed for RDC R-321x system-on-chip, also known 696 as R-8610-(G). 697 If you don't have one of these chips, you should say N here. 698 699config X86_32_NON_STANDARD 700 bool "Support non-standard 32-bit SMP architectures" 701 depends on X86_32 && SMP 702 depends on X86_EXTENDED_PLATFORM 703 help 704 This option compiles in the bigsmp and STA2X11 default 705 subarchitectures. It is intended for a generic binary 706 kernel. If you select them all, kernel will probe it one by 707 one and will fallback to default. 708 709# Alphabetically sorted list of Non standard 32 bit platforms 710 711config X86_SUPPORTS_MEMORY_FAILURE 712 def_bool y 713 # MCE code calls memory_failure(): 714 depends on X86_MCE 715 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 716 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 717 depends on X86_64 || !SPARSEMEM 718 select ARCH_SUPPORTS_MEMORY_FAILURE 719 720config STA2X11 721 bool "STA2X11 Companion Chip Support" 722 depends on X86_32_NON_STANDARD && PCI 723 select SWIOTLB 724 select MFD_STA2X11 725 select GPIOLIB 726 help 727 This adds support for boards based on the STA2X11 IO-Hub, 728 a.k.a. "ConneXt". The chip is used in place of the standard 729 PC chipset, so all "standard" peripherals are missing. If this 730 option is selected the kernel will still be able to boot on 731 standard PC machines. 732 733config X86_32_IRIS 734 tristate "Eurobraille/Iris poweroff module" 735 depends on X86_32 736 help 737 The Iris machines from EuroBraille do not have APM or ACPI support 738 to shut themselves down properly. A special I/O sequence is 739 needed to do so, which is what this module does at 740 kernel shutdown. 741 742 This is only for Iris machines from EuroBraille. 743 744 If unused, say N. 745 746config SCHED_OMIT_FRAME_POINTER 747 def_bool y 748 prompt "Single-depth WCHAN output" 749 depends on X86 750 help 751 Calculate simpler /proc/<PID>/wchan values. If this option 752 is disabled then wchan values will recurse back to the 753 caller function. This provides more accurate wchan values, 754 at the expense of slightly more scheduling overhead. 755 756 If in doubt, say "Y". 757 758menuconfig HYPERVISOR_GUEST 759 bool "Linux guest support" 760 help 761 Say Y here to enable options for running Linux under various hyper- 762 visors. This option enables basic hypervisor detection and platform 763 setup. 764 765 If you say N, all options in this submenu will be skipped and 766 disabled, and Linux guest support won't be built in. 767 768if HYPERVISOR_GUEST 769 770config PARAVIRT 771 bool "Enable paravirtualization code" 772 help 773 This changes the kernel so it can modify itself when it is run 774 under a hypervisor, potentially improving performance significantly 775 over full virtualization. However, when run without a hypervisor 776 the kernel is theoretically slower and slightly larger. 777 778config PARAVIRT_XXL 779 bool 780 781config PARAVIRT_DEBUG 782 bool "paravirt-ops debugging" 783 depends on PARAVIRT && DEBUG_KERNEL 784 help 785 Enable to debug paravirt_ops internals. Specifically, BUG if 786 a paravirt_op is missing when it is called. 787 788config PARAVIRT_SPINLOCKS 789 bool "Paravirtualization layer for spinlocks" 790 depends on PARAVIRT && SMP 791 help 792 Paravirtualized spinlocks allow a pvops backend to replace the 793 spinlock implementation with something virtualization-friendly 794 (for example, block the virtual CPU rather than spinning). 795 796 It has a minimal impact on native kernels and gives a nice performance 797 benefit on paravirtualized KVM / Xen kernels. 798 799 If you are unsure how to answer this question, answer Y. 800 801config X86_HV_CALLBACK_VECTOR 802 def_bool n 803 804source "arch/x86/xen/Kconfig" 805 806config KVM_GUEST 807 bool "KVM Guest support (including kvmclock)" 808 depends on PARAVIRT 809 select PARAVIRT_CLOCK 810 select ARCH_CPUIDLE_HALTPOLL 811 select X86_HV_CALLBACK_VECTOR 812 default y 813 help 814 This option enables various optimizations for running under the KVM 815 hypervisor. It includes a paravirtualized clock, so that instead 816 of relying on a PIT (or probably other) emulation by the 817 underlying device model, the host provides the guest with 818 timing infrastructure such as time of day, and system time 819 820config ARCH_CPUIDLE_HALTPOLL 821 def_bool n 822 prompt "Disable host haltpoll when loading haltpoll driver" 823 help 824 If virtualized under KVM, disable host haltpoll. 825 826config PVH 827 bool "Support for running PVH guests" 828 help 829 This option enables the PVH entry point for guest virtual machines 830 as specified in the x86/HVM direct boot ABI. 831 832config PARAVIRT_TIME_ACCOUNTING 833 bool "Paravirtual steal time accounting" 834 depends on PARAVIRT 835 help 836 Select this option to enable fine granularity task steal time 837 accounting. Time spent executing other tasks in parallel with 838 the current vCPU is discounted from the vCPU power. To account for 839 that, there can be a small performance impact. 840 841 If in doubt, say N here. 842 843config PARAVIRT_CLOCK 844 bool 845 846config JAILHOUSE_GUEST 847 bool "Jailhouse non-root cell support" 848 depends on X86_64 && PCI 849 select X86_PM_TIMER 850 help 851 This option allows to run Linux as guest in a Jailhouse non-root 852 cell. You can leave this option disabled if you only want to start 853 Jailhouse and run Linux afterwards in the root cell. 854 855config ACRN_GUEST 856 bool "ACRN Guest support" 857 depends on X86_64 858 select X86_HV_CALLBACK_VECTOR 859 help 860 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 861 a flexible, lightweight reference open-source hypervisor, built with 862 real-time and safety-criticality in mind. It is built for embedded 863 IOT with small footprint and real-time features. More details can be 864 found in https://projectacrn.org/. 865 866endif #HYPERVISOR_GUEST 867 868source "arch/x86/Kconfig.cpu" 869 870config HPET_TIMER 871 def_bool X86_64 872 prompt "HPET Timer Support" if X86_32 873 help 874 Use the IA-PC HPET (High Precision Event Timer) to manage 875 time in preference to the PIT and RTC, if a HPET is 876 present. 877 HPET is the next generation timer replacing legacy 8254s. 878 The HPET provides a stable time base on SMP 879 systems, unlike the TSC, but it is more expensive to access, 880 as it is off-chip. The interface used is documented 881 in the HPET spec, revision 1. 882 883 You can safely choose Y here. However, HPET will only be 884 activated if the platform and the BIOS support this feature. 885 Otherwise the 8254 will be used for timing services. 886 887 Choose N to continue using the legacy 8254 timer. 888 889config HPET_EMULATE_RTC 890 def_bool y 891 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 892 893config APB_TIMER 894 def_bool y if X86_INTEL_MID 895 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 896 select DW_APB_TIMER 897 depends on X86_INTEL_MID && SFI 898 help 899 APB timer is the replacement for 8254, HPET on X86 MID platforms. 900 The APBT provides a stable time base on SMP 901 systems, unlike the TSC, but it is more expensive to access, 902 as it is off-chip. APB timers are always running regardless of CPU 903 C states, they are used as per CPU clockevent device when possible. 904 905# Mark as expert because too many people got it wrong. 906# The code disables itself when not needed. 907config DMI 908 default y 909 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 910 bool "Enable DMI scanning" if EXPERT 911 help 912 Enabled scanning of DMI to identify machine quirks. Say Y 913 here unless you have verified that your setup is not 914 affected by entries in the DMI blacklist. Required by PNP 915 BIOS code. 916 917config GART_IOMMU 918 bool "Old AMD GART IOMMU support" 919 select DMA_OPS 920 select IOMMU_HELPER 921 select SWIOTLB 922 depends on X86_64 && PCI && AMD_NB 923 help 924 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 925 GART based hardware IOMMUs. 926 927 The GART supports full DMA access for devices with 32-bit access 928 limitations, on systems with more than 3 GB. This is usually needed 929 for USB, sound, many IDE/SATA chipsets and some other devices. 930 931 Newer systems typically have a modern AMD IOMMU, supported via 932 the CONFIG_AMD_IOMMU=y config option. 933 934 In normal configurations this driver is only active when needed: 935 there's more than 3 GB of memory and the system contains a 936 32-bit limited device. 937 938 If unsure, say Y. 939 940config MAXSMP 941 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 942 depends on X86_64 && SMP && DEBUG_KERNEL 943 select CPUMASK_OFFSTACK 944 help 945 Enable maximum number of CPUS and NUMA Nodes for this architecture. 946 If unsure, say N. 947 948# 949# The maximum number of CPUs supported: 950# 951# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 952# and which can be configured interactively in the 953# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 954# 955# The ranges are different on 32-bit and 64-bit kernels, depending on 956# hardware capabilities and scalability features of the kernel. 957# 958# ( If MAXSMP is enabled we just use the highest possible value and disable 959# interactive configuration. ) 960# 961 962config NR_CPUS_RANGE_BEGIN 963 int 964 default NR_CPUS_RANGE_END if MAXSMP 965 default 1 if !SMP 966 default 2 967 968config NR_CPUS_RANGE_END 969 int 970 depends on X86_32 971 default 64 if SMP && X86_BIGSMP 972 default 8 if SMP && !X86_BIGSMP 973 default 1 if !SMP 974 975config NR_CPUS_RANGE_END 976 int 977 depends on X86_64 978 default 8192 if SMP && CPUMASK_OFFSTACK 979 default 512 if SMP && !CPUMASK_OFFSTACK 980 default 1 if !SMP 981 982config NR_CPUS_DEFAULT 983 int 984 depends on X86_32 985 default 32 if X86_BIGSMP 986 default 8 if SMP 987 default 1 if !SMP 988 989config NR_CPUS_DEFAULT 990 int 991 depends on X86_64 992 default 8192 if MAXSMP 993 default 64 if SMP 994 default 1 if !SMP 995 996config NR_CPUS 997 int "Maximum number of CPUs" if SMP && !MAXSMP 998 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 999 default NR_CPUS_DEFAULT 1000 help 1001 This allows you to specify the maximum number of CPUs which this 1002 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1003 supported value is 8192, otherwise the maximum value is 512. The 1004 minimum value which makes sense is 2. 1005 1006 This is purely to save memory: each supported CPU adds about 8KB 1007 to the kernel image. 1008 1009config SCHED_SMT 1010 def_bool y if SMP 1011 1012config SCHED_MC 1013 def_bool y 1014 prompt "Multi-core scheduler support" 1015 depends on SMP 1016 help 1017 Multi-core scheduler support improves the CPU scheduler's decision 1018 making when dealing with multi-core CPU chips at a cost of slightly 1019 increased overhead in some places. If unsure say N here. 1020 1021config SCHED_MC_PRIO 1022 bool "CPU core priorities scheduler support" 1023 depends on SCHED_MC && CPU_SUP_INTEL 1024 select X86_INTEL_PSTATE 1025 select CPU_FREQ 1026 default y 1027 help 1028 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1029 core ordering determined at manufacturing time, which allows 1030 certain cores to reach higher turbo frequencies (when running 1031 single threaded workloads) than others. 1032 1033 Enabling this kernel feature teaches the scheduler about 1034 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1035 scheduler's CPU selection logic accordingly, so that higher 1036 overall system performance can be achieved. 1037 1038 This feature will have no effect on CPUs without this feature. 1039 1040 If unsure say Y here. 1041 1042config UP_LATE_INIT 1043 def_bool y 1044 depends on !SMP && X86_LOCAL_APIC 1045 1046config X86_UP_APIC 1047 bool "Local APIC support on uniprocessors" if !PCI_MSI 1048 default PCI_MSI 1049 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1050 help 1051 A local APIC (Advanced Programmable Interrupt Controller) is an 1052 integrated interrupt controller in the CPU. If you have a single-CPU 1053 system which has a processor with a local APIC, you can say Y here to 1054 enable and use it. If you say Y here even though your machine doesn't 1055 have a local APIC, then the kernel will still run with no slowdown at 1056 all. The local APIC supports CPU-generated self-interrupts (timer, 1057 performance counters), and the NMI watchdog which detects hard 1058 lockups. 1059 1060config X86_UP_IOAPIC 1061 bool "IO-APIC support on uniprocessors" 1062 depends on X86_UP_APIC 1063 help 1064 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1065 SMP-capable replacement for PC-style interrupt controllers. Most 1066 SMP systems and many recent uniprocessor systems have one. 1067 1068 If you have a single-CPU system with an IO-APIC, you can say Y here 1069 to use it. If you say Y here even though your machine doesn't have 1070 an IO-APIC, then the kernel will still run with no slowdown at all. 1071 1072config X86_LOCAL_APIC 1073 def_bool y 1074 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1075 select IRQ_DOMAIN_HIERARCHY 1076 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1077 1078config X86_IO_APIC 1079 def_bool y 1080 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1081 1082config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1083 bool "Reroute for broken boot IRQs" 1084 depends on X86_IO_APIC 1085 help 1086 This option enables a workaround that fixes a source of 1087 spurious interrupts. This is recommended when threaded 1088 interrupt handling is used on systems where the generation of 1089 superfluous "boot interrupts" cannot be disabled. 1090 1091 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1092 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1093 kernel does during interrupt handling). On chipsets where this 1094 boot IRQ generation cannot be disabled, this workaround keeps 1095 the original IRQ line masked so that only the equivalent "boot 1096 IRQ" is delivered to the CPUs. The workaround also tells the 1097 kernel to set up the IRQ handler on the boot IRQ line. In this 1098 way only one interrupt is delivered to the kernel. Otherwise 1099 the spurious second interrupt may cause the kernel to bring 1100 down (vital) interrupt lines. 1101 1102 Only affects "broken" chipsets. Interrupt sharing may be 1103 increased on these systems. 1104 1105config X86_MCE 1106 bool "Machine Check / overheating reporting" 1107 select GENERIC_ALLOCATOR 1108 default y 1109 help 1110 Machine Check support allows the processor to notify the 1111 kernel if it detects a problem (e.g. overheating, data corruption). 1112 The action the kernel takes depends on the severity of the problem, 1113 ranging from warning messages to halting the machine. 1114 1115config X86_MCELOG_LEGACY 1116 bool "Support for deprecated /dev/mcelog character device" 1117 depends on X86_MCE 1118 help 1119 Enable support for /dev/mcelog which is needed by the old mcelog 1120 userspace logging daemon. Consider switching to the new generation 1121 rasdaemon solution. 1122 1123config X86_MCE_INTEL 1124 def_bool y 1125 prompt "Intel MCE features" 1126 depends on X86_MCE && X86_LOCAL_APIC 1127 help 1128 Additional support for intel specific MCE features such as 1129 the thermal monitor. 1130 1131config X86_MCE_AMD 1132 def_bool y 1133 prompt "AMD MCE features" 1134 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1135 help 1136 Additional support for AMD specific MCE features such as 1137 the DRAM Error Threshold. 1138 1139config X86_ANCIENT_MCE 1140 bool "Support for old Pentium 5 / WinChip machine checks" 1141 depends on X86_32 && X86_MCE 1142 help 1143 Include support for machine check handling on old Pentium 5 or WinChip 1144 systems. These typically need to be enabled explicitly on the command 1145 line. 1146 1147config X86_MCE_THRESHOLD 1148 depends on X86_MCE_AMD || X86_MCE_INTEL 1149 def_bool y 1150 1151config X86_MCE_INJECT 1152 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1153 tristate "Machine check injector support" 1154 help 1155 Provide support for injecting machine checks for testing purposes. 1156 If you don't know what a machine check is and you don't do kernel 1157 QA it is safe to say n. 1158 1159config X86_THERMAL_VECTOR 1160 def_bool y 1161 depends on X86_MCE_INTEL 1162 1163source "arch/x86/events/Kconfig" 1164 1165config X86_LEGACY_VM86 1166 bool "Legacy VM86 support" 1167 depends on X86_32 1168 help 1169 This option allows user programs to put the CPU into V8086 1170 mode, which is an 80286-era approximation of 16-bit real mode. 1171 1172 Some very old versions of X and/or vbetool require this option 1173 for user mode setting. Similarly, DOSEMU will use it if 1174 available to accelerate real mode DOS programs. However, any 1175 recent version of DOSEMU, X, or vbetool should be fully 1176 functional even without kernel VM86 support, as they will all 1177 fall back to software emulation. Nevertheless, if you are using 1178 a 16-bit DOS program where 16-bit performance matters, vm86 1179 mode might be faster than emulation and you might want to 1180 enable this option. 1181 1182 Note that any app that works on a 64-bit kernel is unlikely to 1183 need this option, as 64-bit kernels don't, and can't, support 1184 V8086 mode. This option is also unrelated to 16-bit protected 1185 mode and is not needed to run most 16-bit programs under Wine. 1186 1187 Enabling this option increases the complexity of the kernel 1188 and slows down exception handling a tiny bit. 1189 1190 If unsure, say N here. 1191 1192config VM86 1193 bool 1194 default X86_LEGACY_VM86 1195 1196config X86_16BIT 1197 bool "Enable support for 16-bit segments" if EXPERT 1198 default y 1199 depends on MODIFY_LDT_SYSCALL 1200 help 1201 This option is required by programs like Wine to run 16-bit 1202 protected mode legacy code on x86 processors. Disabling 1203 this option saves about 300 bytes on i386, or around 6K text 1204 plus 16K runtime memory on x86-64, 1205 1206config X86_ESPFIX32 1207 def_bool y 1208 depends on X86_16BIT && X86_32 1209 1210config X86_ESPFIX64 1211 def_bool y 1212 depends on X86_16BIT && X86_64 1213 1214config X86_VSYSCALL_EMULATION 1215 bool "Enable vsyscall emulation" if EXPERT 1216 default y 1217 depends on X86_64 1218 help 1219 This enables emulation of the legacy vsyscall page. Disabling 1220 it is roughly equivalent to booting with vsyscall=none, except 1221 that it will also disable the helpful warning if a program 1222 tries to use a vsyscall. With this option set to N, offending 1223 programs will just segfault, citing addresses of the form 1224 0xffffffffff600?00. 1225 1226 This option is required by many programs built before 2013, and 1227 care should be used even with newer programs if set to N. 1228 1229 Disabling this option saves about 7K of kernel size and 1230 possibly 4K of additional runtime pagetable memory. 1231 1232config X86_IOPL_IOPERM 1233 bool "IOPERM and IOPL Emulation" 1234 default y 1235 help 1236 This enables the ioperm() and iopl() syscalls which are necessary 1237 for legacy applications. 1238 1239 Legacy IOPL support is an overbroad mechanism which allows user 1240 space aside of accessing all 65536 I/O ports also to disable 1241 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1242 capabilities and permission from potentially active security 1243 modules. 1244 1245 The emulation restricts the functionality of the syscall to 1246 only allowing the full range I/O port access, but prevents the 1247 ability to disable interrupts from user space which would be 1248 granted if the hardware IOPL mechanism would be used. 1249 1250config TOSHIBA 1251 tristate "Toshiba Laptop support" 1252 depends on X86_32 1253 help 1254 This adds a driver to safely access the System Management Mode of 1255 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1256 not work on models with a Phoenix BIOS. The System Management Mode 1257 is used to set the BIOS and power saving options on Toshiba portables. 1258 1259 For information on utilities to make use of this driver see the 1260 Toshiba Linux utilities web site at: 1261 <http://www.buzzard.org.uk/toshiba/>. 1262 1263 Say Y if you intend to run this kernel on a Toshiba portable. 1264 Say N otherwise. 1265 1266config I8K 1267 tristate "Dell i8k legacy laptop support" 1268 depends on HWMON 1269 depends on PROC_FS 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 help 1305 If you say Y here, you will be able to update the microcode on 1306 Intel and AMD processors. The Intel support is for the IA32 family, 1307 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1308 AMD support is for families 0x10 and later. You will obviously need 1309 the actual microcode binary data itself which is not shipped with 1310 the Linux kernel. 1311 1312 The preferred method to load microcode from a detached initrd is described 1313 in Documentation/x86/microcode.rst. For that you need to enable 1314 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1315 initrd for microcode blobs. 1316 1317 In addition, you can build the microcode into the kernel. For that you 1318 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1319 config option. 1320 1321config MICROCODE_INTEL 1322 bool "Intel microcode loading support" 1323 depends on CPU_SUP_INTEL && MICROCODE 1324 default MICROCODE 1325 help 1326 This options enables microcode patch loading support for Intel 1327 processors. 1328 1329 For the current Intel microcode data package go to 1330 <https://downloadcenter.intel.com> and search for 1331 'Linux Processor Microcode Data File'. 1332 1333config MICROCODE_AMD 1334 bool "AMD microcode loading support" 1335 depends on CPU_SUP_AMD && MICROCODE 1336 help 1337 If you select this option, microcode patch loading support for AMD 1338 processors will be enabled. 1339 1340config MICROCODE_LATE_LOADING 1341 bool "Late microcode loading (DANGEROUS)" 1342 default n 1343 depends on MICROCODE 1344 help 1345 Loading microcode late, when the system is up and executing instructions 1346 is a tricky business and should be avoided if possible. Just the sequence 1347 of synchronizing all cores and SMT threads is one fragile dance which does 1348 not guarantee that cores might not softlock after the loading. Therefore, 1349 use this at your own risk. Late loading taints the kernel too. 1350 1351config X86_MSR 1352 tristate "/dev/cpu/*/msr - Model-specific register support" 1353 help 1354 This device gives privileged processes access to the x86 1355 Model-Specific Registers (MSRs). It is a character device with 1356 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1357 MSR accesses are directed to a specific CPU on multi-processor 1358 systems. 1359 1360config X86_CPUID 1361 tristate "/dev/cpu/*/cpuid - CPU information support" 1362 help 1363 This device gives processes access to the x86 CPUID instruction to 1364 be executed on a specific processor. It is a character device 1365 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1366 /dev/cpu/31/cpuid. 1367 1368choice 1369 prompt "High Memory Support" 1370 default HIGHMEM4G 1371 depends on X86_32 1372 1373config NOHIGHMEM 1374 bool "off" 1375 help 1376 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1377 However, the address space of 32-bit x86 processors is only 4 1378 Gigabytes large. That means that, if you have a large amount of 1379 physical memory, not all of it can be "permanently mapped" by the 1380 kernel. The physical memory that's not permanently mapped is called 1381 "high memory". 1382 1383 If you are compiling a kernel which will never run on a machine with 1384 more than 1 Gigabyte total physical RAM, answer "off" here (default 1385 choice and suitable for most users). This will result in a "3GB/1GB" 1386 split: 3GB are mapped so that each process sees a 3GB virtual memory 1387 space and the remaining part of the 4GB virtual memory space is used 1388 by the kernel to permanently map as much physical memory as 1389 possible. 1390 1391 If the machine has between 1 and 4 Gigabytes physical RAM, then 1392 answer "4GB" here. 1393 1394 If more than 4 Gigabytes is used then answer "64GB" here. This 1395 selection turns Intel PAE (Physical Address Extension) mode on. 1396 PAE implements 3-level paging on IA32 processors. PAE is fully 1397 supported by Linux, PAE mode is implemented on all recent Intel 1398 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1399 then the kernel will not boot on CPUs that don't support PAE! 1400 1401 The actual amount of total physical memory will either be 1402 auto detected or can be forced by using a kernel command line option 1403 such as "mem=256M". (Try "man bootparam" or see the documentation of 1404 your boot loader (lilo or loadlin) about how to pass options to the 1405 kernel at boot time.) 1406 1407 If unsure, say "off". 1408 1409config HIGHMEM4G 1410 bool "4GB" 1411 help 1412 Select this if you have a 32-bit processor and between 1 and 4 1413 gigabytes of physical RAM. 1414 1415config HIGHMEM64G 1416 bool "64GB" 1417 depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6 1418 select X86_PAE 1419 help 1420 Select this if you have a 32-bit processor and more than 4 1421 gigabytes of physical RAM. 1422 1423endchoice 1424 1425choice 1426 prompt "Memory split" if EXPERT 1427 default VMSPLIT_3G 1428 depends on X86_32 1429 help 1430 Select the desired split between kernel and user memory. 1431 1432 If the address range available to the kernel is less than the 1433 physical memory installed, the remaining memory will be available 1434 as "high memory". Accessing high memory is a little more costly 1435 than low memory, as it needs to be mapped into the kernel first. 1436 Note that increasing the kernel address space limits the range 1437 available to user programs, making the address space there 1438 tighter. Selecting anything other than the default 3G/1G split 1439 will also likely make your kernel incompatible with binary-only 1440 kernel modules. 1441 1442 If you are not absolutely sure what you are doing, leave this 1443 option alone! 1444 1445 config VMSPLIT_3G 1446 bool "3G/1G user/kernel split" 1447 config VMSPLIT_3G_OPT 1448 depends on !X86_PAE 1449 bool "3G/1G user/kernel split (for full 1G low memory)" 1450 config VMSPLIT_2G 1451 bool "2G/2G user/kernel split" 1452 config VMSPLIT_2G_OPT 1453 depends on !X86_PAE 1454 bool "2G/2G user/kernel split (for full 2G low memory)" 1455 config VMSPLIT_1G 1456 bool "1G/3G user/kernel split" 1457endchoice 1458 1459config PAGE_OFFSET 1460 hex 1461 default 0xB0000000 if VMSPLIT_3G_OPT 1462 default 0x80000000 if VMSPLIT_2G 1463 default 0x78000000 if VMSPLIT_2G_OPT 1464 default 0x40000000 if VMSPLIT_1G 1465 default 0xC0000000 1466 depends on X86_32 1467 1468config HIGHMEM 1469 def_bool y 1470 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1471 1472config X86_PAE 1473 bool "PAE (Physical Address Extension) Support" 1474 depends on X86_32 && !HIGHMEM4G 1475 select PHYS_ADDR_T_64BIT 1476 select SWIOTLB 1477 help 1478 PAE is required for NX support, and furthermore enables 1479 larger swapspace support for non-overcommit purposes. It 1480 has the cost of more pagetable lookup overhead, and also 1481 consumes more pagetable space per process. 1482 1483config X86_5LEVEL 1484 bool "Enable 5-level page tables support" 1485 default y 1486 select DYNAMIC_MEMORY_LAYOUT 1487 select SPARSEMEM_VMEMMAP 1488 depends on X86_64 1489 help 1490 5-level paging enables access to larger address space: 1491 upto 128 PiB of virtual address space and 4 PiB of 1492 physical address space. 1493 1494 It will be supported by future Intel CPUs. 1495 1496 A kernel with the option enabled can be booted on machines that 1497 support 4- or 5-level paging. 1498 1499 See Documentation/x86/x86_64/5level-paging.rst for more 1500 information. 1501 1502 Say N if unsure. 1503 1504config X86_DIRECT_GBPAGES 1505 def_bool y 1506 depends on X86_64 1507 help 1508 Certain kernel features effectively disable kernel 1509 linear 1 GB mappings (even if the CPU otherwise 1510 supports them), so don't confuse the user by printing 1511 that we have them enabled. 1512 1513config X86_CPA_STATISTICS 1514 bool "Enable statistic for Change Page Attribute" 1515 depends on DEBUG_FS 1516 help 1517 Expose statistics about the Change Page Attribute mechanism, which 1518 helps to determine the effectiveness of preserving large and huge 1519 page mappings when mapping protections are changed. 1520 1521config AMD_MEM_ENCRYPT 1522 bool "AMD Secure Memory Encryption (SME) support" 1523 depends on X86_64 && CPU_SUP_AMD 1524 select DMA_COHERENT_POOL 1525 select DYNAMIC_PHYSICAL_MASK 1526 select ARCH_USE_MEMREMAP_PROT 1527 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1528 select INSTRUCTION_DECODER 1529 select ARCH_HAS_CC_PLATFORM 1530 help 1531 Say yes to enable support for the encryption of system memory. 1532 This requires an AMD processor that supports Secure Memory 1533 Encryption (SME). 1534 1535config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1536 bool "Activate AMD Secure Memory Encryption (SME) by default" 1537 depends on AMD_MEM_ENCRYPT 1538 help 1539 Say yes to have system memory encrypted by default if running on 1540 an AMD processor that supports Secure Memory Encryption (SME). 1541 1542 If set to Y, then the encryption of system memory can be 1543 deactivated with the mem_encrypt=off command line option. 1544 1545 If set to N, then the encryption of system memory can be 1546 activated with the mem_encrypt=on command line option. 1547 1548# Common NUMA Features 1549config NUMA 1550 bool "NUMA Memory Allocation and Scheduler Support" 1551 depends on SMP 1552 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1553 default y if X86_BIGSMP 1554 help 1555 Enable NUMA (Non-Uniform Memory Access) support. 1556 1557 The kernel will try to allocate memory used by a CPU on the 1558 local memory controller of the CPU and add some more 1559 NUMA awareness to the kernel. 1560 1561 For 64-bit this is recommended if the system is Intel Core i7 1562 (or later), AMD Opteron, or EM64T NUMA. 1563 1564 For 32-bit this is only needed if you boot a 32-bit 1565 kernel on a 64-bit NUMA platform. 1566 1567 Otherwise, you should say N. 1568 1569config AMD_NUMA 1570 def_bool y 1571 prompt "Old style AMD Opteron NUMA detection" 1572 depends on X86_64 && NUMA && PCI 1573 help 1574 Enable AMD NUMA node topology detection. You should say Y here if 1575 you have a multi processor AMD system. This uses an old method to 1576 read the NUMA configuration directly from the builtin Northbridge 1577 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1578 which also takes priority if both are compiled in. 1579 1580config X86_64_ACPI_NUMA 1581 def_bool y 1582 prompt "ACPI NUMA detection" 1583 depends on X86_64 && NUMA && ACPI && PCI 1584 select ACPI_NUMA 1585 help 1586 Enable ACPI SRAT based node topology detection. 1587 1588config NUMA_EMU 1589 bool "NUMA emulation" 1590 depends on NUMA 1591 help 1592 Enable NUMA emulation. A flat machine will be split 1593 into virtual nodes when booted with "numa=fake=N", where N is the 1594 number of nodes. This is only useful for debugging. 1595 1596config NODES_SHIFT 1597 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1598 range 1 10 1599 default "10" if MAXSMP 1600 default "6" if X86_64 1601 default "3" 1602 depends on NEED_MULTIPLE_NODES 1603 help 1604 Specify the maximum number of NUMA Nodes available on the target 1605 system. Increases memory reserved to accommodate various tables. 1606 1607config ARCH_FLATMEM_ENABLE 1608 def_bool y 1609 depends on X86_32 && !NUMA 1610 1611config ARCH_SPARSEMEM_ENABLE 1612 def_bool y 1613 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1614 select SPARSEMEM_STATIC if X86_32 1615 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1616 1617config ARCH_SPARSEMEM_DEFAULT 1618 def_bool X86_64 || (NUMA && X86_32) 1619 1620config ARCH_SELECT_MEMORY_MODEL 1621 def_bool y 1622 depends on ARCH_SPARSEMEM_ENABLE 1623 1624config ARCH_MEMORY_PROBE 1625 bool "Enable sysfs memory/probe interface" 1626 depends on X86_64 && MEMORY_HOTPLUG 1627 help 1628 This option enables a sysfs memory/probe interface for testing. 1629 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1630 If you are unsure how to answer this question, answer N. 1631 1632config ARCH_PROC_KCORE_TEXT 1633 def_bool y 1634 depends on X86_64 && PROC_KCORE 1635 1636config ILLEGAL_POINTER_VALUE 1637 hex 1638 default 0 if X86_32 1639 default 0xdead000000000000 if X86_64 1640 1641config X86_PMEM_LEGACY_DEVICE 1642 bool 1643 1644config X86_PMEM_LEGACY 1645 tristate "Support non-standard NVDIMMs and ADR protected memory" 1646 depends on PHYS_ADDR_T_64BIT 1647 depends on BLK_DEV 1648 select X86_PMEM_LEGACY_DEVICE 1649 select NUMA_KEEP_MEMINFO if NUMA 1650 select LIBNVDIMM 1651 help 1652 Treat memory marked using the non-standard e820 type of 12 as used 1653 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1654 The kernel will offer these regions to the 'pmem' driver so 1655 they can be used for persistent storage. 1656 1657 Say Y if unsure. 1658 1659config HIGHPTE 1660 bool "Allocate 3rd-level pagetables from highmem" 1661 depends on HIGHMEM 1662 help 1663 The VM uses one page table entry for each page of physical memory. 1664 For systems with a lot of RAM, this can be wasteful of precious 1665 low memory. Setting this option will put user-space page table 1666 entries in high memory. 1667 1668config X86_CHECK_BIOS_CORRUPTION 1669 bool "Check for low memory corruption" 1670 help 1671 Periodically check for memory corruption in low memory, which 1672 is suspected to be caused by BIOS. Even when enabled in the 1673 configuration, it is disabled at runtime. Enable it by 1674 setting "memory_corruption_check=1" on the kernel command 1675 line. By default it scans the low 64k of memory every 60 1676 seconds; see the memory_corruption_check_size and 1677 memory_corruption_check_period parameters in 1678 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1679 1680 When enabled with the default parameters, this option has 1681 almost no overhead, as it reserves a relatively small amount 1682 of memory and scans it infrequently. It both detects corruption 1683 and prevents it from affecting the running system. 1684 1685 It is, however, intended as a diagnostic tool; if repeatable 1686 BIOS-originated corruption always affects the same memory, 1687 you can use memmap= to prevent the kernel from using that 1688 memory. 1689 1690config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1691 bool "Set the default setting of memory_corruption_check" 1692 depends on X86_CHECK_BIOS_CORRUPTION 1693 default y 1694 help 1695 Set whether the default state of memory_corruption_check is 1696 on or off. 1697 1698config X86_RESERVE_LOW 1699 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1700 default 64 1701 range 4 640 1702 help 1703 Specify the amount of low memory to reserve for the BIOS. 1704 1705 The first page contains BIOS data structures that the kernel 1706 must not use, so that page must always be reserved. 1707 1708 By default we reserve the first 64K of physical RAM, as a 1709 number of BIOSes are known to corrupt that memory range 1710 during events such as suspend/resume or monitor cable 1711 insertion, so it must not be used by the kernel. 1712 1713 You can set this to 4 if you are absolutely sure that you 1714 trust the BIOS to get all its memory reservations and usages 1715 right. If you know your BIOS have problems beyond the 1716 default 64K area, you can set this to 640 to avoid using the 1717 entire low memory range. 1718 1719 If you have doubts about the BIOS (e.g. suspend/resume does 1720 not work or there's kernel crashes after certain hardware 1721 hotplug events) then you might want to enable 1722 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1723 typical corruption patterns. 1724 1725 Leave this to the default value of 64 if you are unsure. 1726 1727config MATH_EMULATION 1728 bool 1729 depends on MODIFY_LDT_SYSCALL 1730 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1731 help 1732 Linux can emulate a math coprocessor (used for floating point 1733 operations) if you don't have one. 486DX and Pentium processors have 1734 a math coprocessor built in, 486SX and 386 do not, unless you added 1735 a 487DX or 387, respectively. (The messages during boot time can 1736 give you some hints here ["man dmesg"].) Everyone needs either a 1737 coprocessor or this emulation. 1738 1739 If you don't have a math coprocessor, you need to say Y here; if you 1740 say Y here even though you have a coprocessor, the coprocessor will 1741 be used nevertheless. (This behavior can be changed with the kernel 1742 command line option "no387", which comes handy if your coprocessor 1743 is broken. Try "man bootparam" or see the documentation of your boot 1744 loader (lilo or loadlin) about how to pass options to the kernel at 1745 boot time.) This means that it is a good idea to say Y here if you 1746 intend to use this kernel on different machines. 1747 1748 More information about the internals of the Linux math coprocessor 1749 emulation can be found in <file:arch/x86/math-emu/README>. 1750 1751 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1752 kernel, it won't hurt. 1753 1754config MTRR 1755 def_bool y 1756 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1757 help 1758 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1759 the Memory Type Range Registers (MTRRs) may be used to control 1760 processor access to memory ranges. This is most useful if you have 1761 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1762 allows bus write transfers to be combined into a larger transfer 1763 before bursting over the PCI/AGP bus. This can increase performance 1764 of image write operations 2.5 times or more. Saying Y here creates a 1765 /proc/mtrr file which may be used to manipulate your processor's 1766 MTRRs. Typically the X server should use this. 1767 1768 This code has a reasonably generic interface so that similar 1769 control registers on other processors can be easily supported 1770 as well: 1771 1772 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1773 Registers (ARRs) which provide a similar functionality to MTRRs. For 1774 these, the ARRs are used to emulate the MTRRs. 1775 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1776 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1777 write-combining. All of these processors are supported by this code 1778 and it makes sense to say Y here if you have one of them. 1779 1780 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1781 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1782 can lead to all sorts of problems, so it's good to say Y here. 1783 1784 You can safely say Y even if your machine doesn't have MTRRs, you'll 1785 just add about 9 KB to your kernel. 1786 1787 See <file:Documentation/x86/mtrr.rst> for more information. 1788 1789config MTRR_SANITIZER 1790 def_bool y 1791 prompt "MTRR cleanup support" 1792 depends on MTRR 1793 help 1794 Convert MTRR layout from continuous to discrete, so X drivers can 1795 add writeback entries. 1796 1797 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1798 The largest mtrr entry size for a continuous block can be set with 1799 mtrr_chunk_size. 1800 1801 If unsure, say Y. 1802 1803config MTRR_SANITIZER_ENABLE_DEFAULT 1804 int "MTRR cleanup enable value (0-1)" 1805 range 0 1 1806 default "0" 1807 depends on MTRR_SANITIZER 1808 help 1809 Enable mtrr cleanup default value 1810 1811config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1812 int "MTRR cleanup spare reg num (0-7)" 1813 range 0 7 1814 default "1" 1815 depends on MTRR_SANITIZER 1816 help 1817 mtrr cleanup spare entries default, it can be changed via 1818 mtrr_spare_reg_nr=N on the kernel command line. 1819 1820config X86_PAT 1821 def_bool y 1822 prompt "x86 PAT support" if EXPERT 1823 depends on MTRR 1824 help 1825 Use PAT attributes to setup page level cache control. 1826 1827 PATs are the modern equivalents of MTRRs and are much more 1828 flexible than MTRRs. 1829 1830 Say N here if you see bootup problems (boot crash, boot hang, 1831 spontaneous reboots) or a non-working video driver. 1832 1833 If unsure, say Y. 1834 1835config ARCH_USES_PG_UNCACHED 1836 def_bool y 1837 depends on X86_PAT 1838 1839config ARCH_RANDOM 1840 def_bool y 1841 prompt "x86 architectural random number generator" if EXPERT 1842 help 1843 Enable the x86 architectural RDRAND instruction 1844 (Intel Bull Mountain technology) to generate random numbers. 1845 If supported, this is a high bandwidth, cryptographically 1846 secure hardware random number generator. 1847 1848config X86_SMAP 1849 def_bool y 1850 prompt "Supervisor Mode Access Prevention" if EXPERT 1851 help 1852 Supervisor Mode Access Prevention (SMAP) is a security 1853 feature in newer Intel processors. There is a small 1854 performance cost if this enabled and turned on; there is 1855 also a small increase in the kernel size if this is enabled. 1856 1857 If unsure, say Y. 1858 1859config X86_UMIP 1860 def_bool y 1861 prompt "User Mode Instruction Prevention" if EXPERT 1862 help 1863 User Mode Instruction Prevention (UMIP) is a security feature in 1864 some x86 processors. If enabled, a general protection fault is 1865 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1866 executed in user mode. These instructions unnecessarily expose 1867 information about the hardware state. 1868 1869 The vast majority of applications do not use these instructions. 1870 For the very few that do, software emulation is provided in 1871 specific cases in protected and virtual-8086 modes. Emulated 1872 results are dummy. 1873 1874config X86_INTEL_MEMORY_PROTECTION_KEYS 1875 prompt "Memory Protection Keys" 1876 def_bool y 1877 # Note: only available in 64-bit mode 1878 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1879 select ARCH_USES_HIGH_VMA_FLAGS 1880 select ARCH_HAS_PKEYS 1881 help 1882 Memory Protection Keys provides a mechanism for enforcing 1883 page-based protections, but without requiring modification of the 1884 page tables when an application changes protection domains. 1885 1886 For details, see Documentation/core-api/protection-keys.rst 1887 1888 If unsure, say y. 1889 1890choice 1891 prompt "TSX enable mode" 1892 depends on CPU_SUP_INTEL 1893 default X86_INTEL_TSX_MODE_OFF 1894 help 1895 Intel's TSX (Transactional Synchronization Extensions) feature 1896 allows to optimize locking protocols through lock elision which 1897 can lead to a noticeable performance boost. 1898 1899 On the other hand it has been shown that TSX can be exploited 1900 to form side channel attacks (e.g. TAA) and chances are there 1901 will be more of those attacks discovered in the future. 1902 1903 Therefore TSX is not enabled by default (aka tsx=off). An admin 1904 might override this decision by tsx=on the command line parameter. 1905 Even with TSX enabled, the kernel will attempt to enable the best 1906 possible TAA mitigation setting depending on the microcode available 1907 for the particular machine. 1908 1909 This option allows to set the default tsx mode between tsx=on, =off 1910 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1911 details. 1912 1913 Say off if not sure, auto if TSX is in use but it should be used on safe 1914 platforms or on if TSX is in use and the security aspect of tsx is not 1915 relevant. 1916 1917config X86_INTEL_TSX_MODE_OFF 1918 bool "off" 1919 help 1920 TSX is disabled if possible - equals to tsx=off command line parameter. 1921 1922config X86_INTEL_TSX_MODE_ON 1923 bool "on" 1924 help 1925 TSX is always enabled on TSX capable HW - equals the tsx=on command 1926 line parameter. 1927 1928config X86_INTEL_TSX_MODE_AUTO 1929 bool "auto" 1930 help 1931 TSX is enabled on TSX capable HW that is believed to be safe against 1932 side channel attacks- equals the tsx=auto command line parameter. 1933endchoice 1934 1935config EFI 1936 bool "EFI runtime service support" 1937 depends on ACPI 1938 select UCS2_STRING 1939 select EFI_RUNTIME_WRAPPERS 1940 select ARCH_USE_MEMREMAP_PROT 1941 help 1942 This enables the kernel to use EFI runtime services that are 1943 available (such as the EFI variable services). 1944 1945 This option is only useful on systems that have EFI firmware. 1946 In addition, you should use the latest ELILO loader available 1947 at <http://elilo.sourceforge.net> in order to take advantage 1948 of EFI runtime services. However, even with this option, the 1949 resultant kernel should continue to boot on existing non-EFI 1950 platforms. 1951 1952config EFI_STUB 1953 bool "EFI stub support" 1954 depends on EFI && !X86_USE_3DNOW 1955 select RELOCATABLE 1956 help 1957 This kernel feature allows a bzImage to be loaded directly 1958 by EFI firmware without the use of a bootloader. 1959 1960 See Documentation/admin-guide/efi-stub.rst for more information. 1961 1962config EFI_MIXED 1963 bool "EFI mixed-mode support" 1964 depends on EFI_STUB && X86_64 1965 help 1966 Enabling this feature allows a 64-bit kernel to be booted 1967 on a 32-bit firmware, provided that your CPU supports 64-bit 1968 mode. 1969 1970 Note that it is not possible to boot a mixed-mode enabled 1971 kernel via the EFI boot stub - a bootloader that supports 1972 the EFI handover protocol must be used. 1973 1974 If unsure, say N. 1975 1976source "kernel/Kconfig.hz" 1977 1978config KEXEC 1979 bool "kexec system call" 1980 select KEXEC_CORE 1981 help 1982 kexec is a system call that implements the ability to shutdown your 1983 current kernel, and to start another kernel. It is like a reboot 1984 but it is independent of the system firmware. And like a reboot 1985 you can start any kernel with it, not just Linux. 1986 1987 The name comes from the similarity to the exec system call. 1988 1989 It is an ongoing process to be certain the hardware in a machine 1990 is properly shutdown, so do not be surprised if this code does not 1991 initially work for you. As of this writing the exact hardware 1992 interface is strongly in flux, so no good recommendation can be 1993 made. 1994 1995config KEXEC_FILE 1996 bool "kexec file based system call" 1997 select KEXEC_CORE 1998 select BUILD_BIN2C 1999 depends on X86_64 2000 depends on CRYPTO=y 2001 depends on CRYPTO_SHA256=y 2002 help 2003 This is new version of kexec system call. This system call is 2004 file based and takes file descriptors as system call argument 2005 for kernel and initramfs as opposed to list of segments as 2006 accepted by previous system call. 2007 2008config ARCH_HAS_KEXEC_PURGATORY 2009 def_bool KEXEC_FILE 2010 2011config KEXEC_SIG 2012 bool "Verify kernel signature during kexec_file_load() syscall" 2013 depends on KEXEC_FILE 2014 help 2015 2016 This option makes the kexec_file_load() syscall check for a valid 2017 signature of the kernel image. The image can still be loaded without 2018 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2019 there's a signature that we can check, then it must be valid. 2020 2021 In addition to this option, you need to enable signature 2022 verification for the corresponding kernel image type being 2023 loaded in order for this to work. 2024 2025config KEXEC_SIG_FORCE 2026 bool "Require a valid signature in kexec_file_load() syscall" 2027 depends on KEXEC_SIG 2028 help 2029 This option makes kernel signature verification mandatory for 2030 the kexec_file_load() syscall. 2031 2032config KEXEC_BZIMAGE_VERIFY_SIG 2033 bool "Enable bzImage signature verification support" 2034 depends on KEXEC_SIG 2035 depends on SIGNED_PE_FILE_VERIFICATION 2036 select SYSTEM_TRUSTED_KEYRING 2037 help 2038 Enable bzImage signature verification support. 2039 2040config CRASH_DUMP 2041 bool "kernel crash dumps" 2042 depends on X86_64 || (X86_32 && HIGHMEM) 2043 help 2044 Generate crash dump after being started by kexec. 2045 This should be normally only set in special crash dump kernels 2046 which are loaded in the main kernel with kexec-tools into 2047 a specially reserved region and then later executed after 2048 a crash by kdump/kexec. The crash dump kernel must be compiled 2049 to a memory address not used by the main kernel or BIOS using 2050 PHYSICAL_START, or it must be built as a relocatable image 2051 (CONFIG_RELOCATABLE=y). 2052 For more details see Documentation/admin-guide/kdump/kdump.rst 2053 2054config KEXEC_JUMP 2055 bool "kexec jump" 2056 depends on KEXEC && HIBERNATION 2057 help 2058 Jump between original kernel and kexeced kernel and invoke 2059 code in physical address mode via KEXEC 2060 2061config PHYSICAL_START 2062 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2063 default "0x1000000" 2064 help 2065 This gives the physical address where the kernel is loaded. 2066 2067 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2068 bzImage will decompress itself to above physical address and 2069 run from there. Otherwise, bzImage will run from the address where 2070 it has been loaded by the boot loader and will ignore above physical 2071 address. 2072 2073 In normal kdump cases one does not have to set/change this option 2074 as now bzImage can be compiled as a completely relocatable image 2075 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2076 address. This option is mainly useful for the folks who don't want 2077 to use a bzImage for capturing the crash dump and want to use a 2078 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2079 to be specifically compiled to run from a specific memory area 2080 (normally a reserved region) and this option comes handy. 2081 2082 So if you are using bzImage for capturing the crash dump, 2083 leave the value here unchanged to 0x1000000 and set 2084 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2085 for capturing the crash dump change this value to start of 2086 the reserved region. In other words, it can be set based on 2087 the "X" value as specified in the "crashkernel=YM@XM" 2088 command line boot parameter passed to the panic-ed 2089 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2090 for more details about crash dumps. 2091 2092 Usage of bzImage for capturing the crash dump is recommended as 2093 one does not have to build two kernels. Same kernel can be used 2094 as production kernel and capture kernel. Above option should have 2095 gone away after relocatable bzImage support is introduced. But it 2096 is present because there are users out there who continue to use 2097 vmlinux for dump capture. This option should go away down the 2098 line. 2099 2100 Don't change this unless you know what you are doing. 2101 2102config RELOCATABLE 2103 bool "Build a relocatable kernel" 2104 default y 2105 help 2106 This builds a kernel image that retains relocation information 2107 so it can be loaded someplace besides the default 1MB. 2108 The relocations tend to make the kernel binary about 10% larger, 2109 but are discarded at runtime. 2110 2111 One use is for the kexec on panic case where the recovery kernel 2112 must live at a different physical address than the primary 2113 kernel. 2114 2115 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2116 it has been loaded at and the compile time physical address 2117 (CONFIG_PHYSICAL_START) is used as the minimum location. 2118 2119config RANDOMIZE_BASE 2120 bool "Randomize the address of the kernel image (KASLR)" 2121 depends on RELOCATABLE 2122 default y 2123 help 2124 In support of Kernel Address Space Layout Randomization (KASLR), 2125 this randomizes the physical address at which the kernel image 2126 is decompressed and the virtual address where the kernel 2127 image is mapped, as a security feature that deters exploit 2128 attempts relying on knowledge of the location of kernel 2129 code internals. 2130 2131 On 64-bit, the kernel physical and virtual addresses are 2132 randomized separately. The physical address will be anywhere 2133 between 16MB and the top of physical memory (up to 64TB). The 2134 virtual address will be randomized from 16MB up to 1GB (9 bits 2135 of entropy). Note that this also reduces the memory space 2136 available to kernel modules from 1.5GB to 1GB. 2137 2138 On 32-bit, the kernel physical and virtual addresses are 2139 randomized together. They will be randomized from 16MB up to 2140 512MB (8 bits of entropy). 2141 2142 Entropy is generated using the RDRAND instruction if it is 2143 supported. If RDTSC is supported, its value is mixed into 2144 the entropy pool as well. If neither RDRAND nor RDTSC are 2145 supported, then entropy is read from the i8254 timer. The 2146 usable entropy is limited by the kernel being built using 2147 2GB addressing, and that PHYSICAL_ALIGN must be at a 2148 minimum of 2MB. As a result, only 10 bits of entropy are 2149 theoretically possible, but the implementations are further 2150 limited due to memory layouts. 2151 2152 If unsure, say Y. 2153 2154# Relocation on x86 needs some additional build support 2155config X86_NEED_RELOCS 2156 def_bool y 2157 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2158 2159config PHYSICAL_ALIGN 2160 hex "Alignment value to which kernel should be aligned" 2161 default "0x200000" 2162 range 0x2000 0x1000000 if X86_32 2163 range 0x200000 0x1000000 if X86_64 2164 help 2165 This value puts the alignment restrictions on physical address 2166 where kernel is loaded and run from. Kernel is compiled for an 2167 address which meets above alignment restriction. 2168 2169 If bootloader loads the kernel at a non-aligned address and 2170 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2171 address aligned to above value and run from there. 2172 2173 If bootloader loads the kernel at a non-aligned address and 2174 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2175 load address and decompress itself to the address it has been 2176 compiled for and run from there. The address for which kernel is 2177 compiled already meets above alignment restrictions. Hence the 2178 end result is that kernel runs from a physical address meeting 2179 above alignment restrictions. 2180 2181 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2182 this value must be a multiple of 0x200000. 2183 2184 Don't change this unless you know what you are doing. 2185 2186config DYNAMIC_MEMORY_LAYOUT 2187 bool 2188 help 2189 This option makes base addresses of vmalloc and vmemmap as well as 2190 __PAGE_OFFSET movable during boot. 2191 2192config RANDOMIZE_MEMORY 2193 bool "Randomize the kernel memory sections" 2194 depends on X86_64 2195 depends on RANDOMIZE_BASE 2196 select DYNAMIC_MEMORY_LAYOUT 2197 default RANDOMIZE_BASE 2198 help 2199 Randomizes the base virtual address of kernel memory sections 2200 (physical memory mapping, vmalloc & vmemmap). This security feature 2201 makes exploits relying on predictable memory locations less reliable. 2202 2203 The order of allocations remains unchanged. Entropy is generated in 2204 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2205 configuration have in average 30,000 different possible virtual 2206 addresses for each memory section. 2207 2208 If unsure, say Y. 2209 2210config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2211 hex "Physical memory mapping padding" if EXPERT 2212 depends on RANDOMIZE_MEMORY 2213 default "0xa" if MEMORY_HOTPLUG 2214 default "0x0" 2215 range 0x1 0x40 if MEMORY_HOTPLUG 2216 range 0x0 0x40 2217 help 2218 Define the padding in terabytes added to the existing physical 2219 memory size during kernel memory randomization. It is useful 2220 for memory hotplug support but reduces the entropy available for 2221 address randomization. 2222 2223 If unsure, leave at the default value. 2224 2225config HOTPLUG_CPU 2226 def_bool y 2227 depends on SMP 2228 2229config BOOTPARAM_HOTPLUG_CPU0 2230 bool "Set default setting of cpu0_hotpluggable" 2231 depends on HOTPLUG_CPU 2232 help 2233 Set whether default state of cpu0_hotpluggable is on or off. 2234 2235 Say Y here to enable CPU0 hotplug by default. If this switch 2236 is turned on, there is no need to give cpu0_hotplug kernel 2237 parameter and the CPU0 hotplug feature is enabled by default. 2238 2239 Please note: there are two known CPU0 dependencies if you want 2240 to enable the CPU0 hotplug feature either by this switch or by 2241 cpu0_hotplug kernel parameter. 2242 2243 First, resume from hibernate or suspend always starts from CPU0. 2244 So hibernate and suspend are prevented if CPU0 is offline. 2245 2246 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2247 offline if any interrupt can not migrate out of CPU0. There may 2248 be other CPU0 dependencies. 2249 2250 Please make sure the dependencies are under your control before 2251 you enable this feature. 2252 2253 Say N if you don't want to enable CPU0 hotplug feature by default. 2254 You still can enable the CPU0 hotplug feature at boot by kernel 2255 parameter cpu0_hotplug. 2256 2257config DEBUG_HOTPLUG_CPU0 2258 def_bool n 2259 prompt "Debug CPU0 hotplug" 2260 depends on HOTPLUG_CPU 2261 help 2262 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2263 soon as possible and boots up userspace with CPU0 offlined. User 2264 can online CPU0 back after boot time. 2265 2266 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2267 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2268 compilation or giving cpu0_hotplug kernel parameter at boot. 2269 2270 If unsure, say N. 2271 2272config COMPAT_VDSO 2273 def_bool n 2274 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2275 depends on COMPAT_32 2276 help 2277 Certain buggy versions of glibc will crash if they are 2278 presented with a 32-bit vDSO that is not mapped at the address 2279 indicated in its segment table. 2280 2281 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2282 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2283 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2284 the only released version with the bug, but OpenSUSE 9 2285 contains a buggy "glibc 2.3.2". 2286 2287 The symptom of the bug is that everything crashes on startup, saying: 2288 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2289 2290 Saying Y here changes the default value of the vdso32 boot 2291 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2292 This works around the glibc bug but hurts performance. 2293 2294 If unsure, say N: if you are compiling your own kernel, you 2295 are unlikely to be using a buggy version of glibc. 2296 2297choice 2298 prompt "vsyscall table for legacy applications" 2299 depends on X86_64 2300 default LEGACY_VSYSCALL_XONLY 2301 help 2302 Legacy user code that does not know how to find the vDSO expects 2303 to be able to issue three syscalls by calling fixed addresses in 2304 kernel space. Since this location is not randomized with ASLR, 2305 it can be used to assist security vulnerability exploitation. 2306 2307 This setting can be changed at boot time via the kernel command 2308 line parameter vsyscall=[emulate|xonly|none]. 2309 2310 On a system with recent enough glibc (2.14 or newer) and no 2311 static binaries, you can say None without a performance penalty 2312 to improve security. 2313 2314 If unsure, select "Emulate execution only". 2315 2316 config LEGACY_VSYSCALL_EMULATE 2317 bool "Full emulation" 2318 help 2319 The kernel traps and emulates calls into the fixed vsyscall 2320 address mapping. This makes the mapping non-executable, but 2321 it still contains readable known contents, which could be 2322 used in certain rare security vulnerability exploits. This 2323 configuration is recommended when using legacy userspace 2324 that still uses vsyscalls along with legacy binary 2325 instrumentation tools that require code to be readable. 2326 2327 An example of this type of legacy userspace is running 2328 Pin on an old binary that still uses vsyscalls. 2329 2330 config LEGACY_VSYSCALL_XONLY 2331 bool "Emulate execution only" 2332 help 2333 The kernel traps and emulates calls into the fixed vsyscall 2334 address mapping and does not allow reads. This 2335 configuration is recommended when userspace might use the 2336 legacy vsyscall area but support for legacy binary 2337 instrumentation of legacy code is not needed. It mitigates 2338 certain uses of the vsyscall area as an ASLR-bypassing 2339 buffer. 2340 2341 config LEGACY_VSYSCALL_NONE 2342 bool "None" 2343 help 2344 There will be no vsyscall mapping at all. This will 2345 eliminate any risk of ASLR bypass due to the vsyscall 2346 fixed address mapping. Attempts to use the vsyscalls 2347 will be reported to dmesg, so that either old or 2348 malicious userspace programs can be identified. 2349 2350endchoice 2351 2352config CMDLINE_BOOL 2353 bool "Built-in kernel command line" 2354 help 2355 Allow for specifying boot arguments to the kernel at 2356 build time. On some systems (e.g. embedded ones), it is 2357 necessary or convenient to provide some or all of the 2358 kernel boot arguments with the kernel itself (that is, 2359 to not rely on the boot loader to provide them.) 2360 2361 To compile command line arguments into the kernel, 2362 set this option to 'Y', then fill in the 2363 boot arguments in CONFIG_CMDLINE. 2364 2365 Systems with fully functional boot loaders (i.e. non-embedded) 2366 should leave this option set to 'N'. 2367 2368config CMDLINE 2369 string "Built-in kernel command string" 2370 depends on CMDLINE_BOOL 2371 default "" 2372 help 2373 Enter arguments here that should be compiled into the kernel 2374 image and used at boot time. If the boot loader provides a 2375 command line at boot time, it is appended to this string to 2376 form the full kernel command line, when the system boots. 2377 2378 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2379 change this behavior. 2380 2381 In most cases, the command line (whether built-in or provided 2382 by the boot loader) should specify the device for the root 2383 file system. 2384 2385config CMDLINE_OVERRIDE 2386 bool "Built-in command line overrides boot loader arguments" 2387 depends on CMDLINE_BOOL && CMDLINE != "" 2388 help 2389 Set this option to 'Y' to have the kernel ignore the boot loader 2390 command line, and use ONLY the built-in command line. 2391 2392 This is used to work around broken boot loaders. This should 2393 be set to 'N' under normal conditions. 2394 2395config MODIFY_LDT_SYSCALL 2396 bool "Enable the LDT (local descriptor table)" if EXPERT 2397 default y 2398 help 2399 Linux can allow user programs to install a per-process x86 2400 Local Descriptor Table (LDT) using the modify_ldt(2) system 2401 call. This is required to run 16-bit or segmented code such as 2402 DOSEMU or some Wine programs. It is also used by some very old 2403 threading libraries. 2404 2405 Enabling this feature adds a small amount of overhead to 2406 context switches and increases the low-level kernel attack 2407 surface. Disabling it removes the modify_ldt(2) system call. 2408 2409 Saying 'N' here may make sense for embedded or server kernels. 2410 2411source "kernel/livepatch/Kconfig" 2412 2413endmenu 2414 2415config CC_HAS_SLS 2416 def_bool $(cc-option,-mharden-sls=all) 2417 2418config CC_HAS_RETURN_THUNK 2419 def_bool $(cc-option,-mfunction-return=thunk-extern) 2420 2421menuconfig SPECULATION_MITIGATIONS 2422 bool "Mitigations for speculative execution vulnerabilities" 2423 default y 2424 help 2425 Say Y here to enable options which enable mitigations for 2426 speculative execution hardware vulnerabilities. 2427 2428 If you say N, all mitigations will be disabled. You really 2429 should know what you are doing to say so. 2430 2431if SPECULATION_MITIGATIONS 2432 2433config PAGE_TABLE_ISOLATION 2434 bool "Remove the kernel mapping in user mode" 2435 default y 2436 depends on (X86_64 || X86_PAE) 2437 help 2438 This feature reduces the number of hardware side channels by 2439 ensuring that the majority of kernel addresses are not mapped 2440 into userspace. 2441 2442 See Documentation/x86/pti.rst for more details. 2443 2444config RETPOLINE 2445 bool "Avoid speculative indirect branches in kernel" 2446 default y 2447 help 2448 Compile kernel with the retpoline compiler options to guard against 2449 kernel-to-user data leaks by avoiding speculative indirect 2450 branches. Requires a compiler with -mindirect-branch=thunk-extern 2451 support for full protection. The kernel may run slower. 2452 2453config RETHUNK 2454 bool "Enable return-thunks" 2455 depends on RETPOLINE && CC_HAS_RETURN_THUNK 2456 default y if X86_64 2457 help 2458 Compile the kernel with the return-thunks compiler option to guard 2459 against kernel-to-user data leaks by avoiding return speculation. 2460 Requires a compiler with -mfunction-return=thunk-extern 2461 support for full protection. The kernel may run slower. 2462 2463config CPU_UNRET_ENTRY 2464 bool "Enable UNRET on kernel entry" 2465 depends on CPU_SUP_AMD && RETHUNK && X86_64 2466 default y 2467 help 2468 Compile the kernel with support for the retbleed=unret mitigation. 2469 2470config CPU_IBPB_ENTRY 2471 bool "Enable IBPB on kernel entry" 2472 depends on CPU_SUP_AMD && X86_64 2473 default y 2474 help 2475 Compile the kernel with support for the retbleed=ibpb mitigation. 2476 2477config CPU_IBRS_ENTRY 2478 bool "Enable IBRS on kernel entry" 2479 depends on CPU_SUP_INTEL && X86_64 2480 default y 2481 help 2482 Compile the kernel with support for the spectre_v2=ibrs mitigation. 2483 This mitigates both spectre_v2 and retbleed at great cost to 2484 performance. 2485 2486config CPU_SRSO 2487 bool "Mitigate speculative RAS overflow on AMD" 2488 depends on CPU_SUP_AMD && X86_64 && RETHUNK 2489 default y 2490 help 2491 Enable the SRSO mitigation needed on AMD Zen1-4 machines. 2492 2493config SLS 2494 bool "Mitigate Straight-Line-Speculation" 2495 depends on CC_HAS_SLS && X86_64 2496 default n 2497 help 2498 Compile the kernel with straight-line-speculation options to guard 2499 against straight line speculation. The kernel image might be slightly 2500 larger. 2501 2502config GDS_FORCE_MITIGATION 2503 bool "Force GDS Mitigation" 2504 depends on CPU_SUP_INTEL 2505 default n 2506 help 2507 Gather Data Sampling (GDS) is a hardware vulnerability which allows 2508 unprivileged speculative access to data which was previously stored in 2509 vector registers. 2510 2511 This option is equivalent to setting gather_data_sampling=force on the 2512 command line. The microcode mitigation is used if present, otherwise 2513 AVX is disabled as a mitigation. On affected systems that are missing 2514 the microcode any userspace code that unconditionally uses AVX will 2515 break with this option set. 2516 2517 Setting this option on systems not vulnerable to GDS has no effect. 2518 2519 If in doubt, say N. 2520 2521endif 2522 2523config ARCH_HAS_ADD_PAGES 2524 def_bool y 2525 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2526 2527config ARCH_ENABLE_MEMORY_HOTPLUG 2528 def_bool y 2529 depends on X86_64 || (X86_32 && HIGHMEM) 2530 2531config ARCH_ENABLE_MEMORY_HOTREMOVE 2532 def_bool y 2533 depends on MEMORY_HOTPLUG 2534 2535config USE_PERCPU_NUMA_NODE_ID 2536 def_bool y 2537 depends on NUMA 2538 2539config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2540 def_bool y 2541 depends on X86_64 || X86_PAE 2542 2543config ARCH_ENABLE_HUGEPAGE_MIGRATION 2544 def_bool y 2545 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2546 2547config ARCH_ENABLE_THP_MIGRATION 2548 def_bool y 2549 depends on X86_64 && TRANSPARENT_HUGEPAGE 2550 2551menu "Power management and ACPI options" 2552 2553config ARCH_HIBERNATION_HEADER 2554 def_bool y 2555 depends on HIBERNATION 2556 2557source "kernel/power/Kconfig" 2558 2559source "drivers/acpi/Kconfig" 2560 2561source "drivers/sfi/Kconfig" 2562 2563config X86_APM_BOOT 2564 def_bool y 2565 depends on APM 2566 2567menuconfig APM 2568 tristate "APM (Advanced Power Management) BIOS support" 2569 depends on X86_32 && PM_SLEEP 2570 help 2571 APM is a BIOS specification for saving power using several different 2572 techniques. This is mostly useful for battery powered laptops with 2573 APM compliant BIOSes. If you say Y here, the system time will be 2574 reset after a RESUME operation, the /proc/apm device will provide 2575 battery status information, and user-space programs will receive 2576 notification of APM "events" (e.g. battery status change). 2577 2578 If you select "Y" here, you can disable actual use of the APM 2579 BIOS by passing the "apm=off" option to the kernel at boot time. 2580 2581 Note that the APM support is almost completely disabled for 2582 machines with more than one CPU. 2583 2584 In order to use APM, you will need supporting software. For location 2585 and more information, read <file:Documentation/power/apm-acpi.rst> 2586 and the Battery Powered Linux mini-HOWTO, available from 2587 <http://www.tldp.org/docs.html#howto>. 2588 2589 This driver does not spin down disk drives (see the hdparm(8) 2590 manpage ("man 8 hdparm") for that), and it doesn't turn off 2591 VESA-compliant "green" monitors. 2592 2593 This driver does not support the TI 4000M TravelMate and the ACER 2594 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2595 desktop machines also don't have compliant BIOSes, and this driver 2596 may cause those machines to panic during the boot phase. 2597 2598 Generally, if you don't have a battery in your machine, there isn't 2599 much point in using this driver and you should say N. If you get 2600 random kernel OOPSes or reboots that don't seem to be related to 2601 anything, try disabling/enabling this option (or disabling/enabling 2602 APM in your BIOS). 2603 2604 Some other things you should try when experiencing seemingly random, 2605 "weird" problems: 2606 2607 1) make sure that you have enough swap space and that it is 2608 enabled. 2609 2) pass the "no-hlt" option to the kernel 2610 3) switch on floating point emulation in the kernel and pass 2611 the "no387" option to the kernel 2612 4) pass the "floppy=nodma" option to the kernel 2613 5) pass the "mem=4M" option to the kernel (thereby disabling 2614 all but the first 4 MB of RAM) 2615 6) make sure that the CPU is not over clocked. 2616 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2617 8) disable the cache from your BIOS settings 2618 9) install a fan for the video card or exchange video RAM 2619 10) install a better fan for the CPU 2620 11) exchange RAM chips 2621 12) exchange the motherboard. 2622 2623 To compile this driver as a module, choose M here: the 2624 module will be called apm. 2625 2626if APM 2627 2628config APM_IGNORE_USER_SUSPEND 2629 bool "Ignore USER SUSPEND" 2630 help 2631 This option will ignore USER SUSPEND requests. On machines with a 2632 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2633 series notebooks, it is necessary to say Y because of a BIOS bug. 2634 2635config APM_DO_ENABLE 2636 bool "Enable PM at boot time" 2637 help 2638 Enable APM features at boot time. From page 36 of the APM BIOS 2639 specification: "When disabled, the APM BIOS does not automatically 2640 power manage devices, enter the Standby State, enter the Suspend 2641 State, or take power saving steps in response to CPU Idle calls." 2642 This driver will make CPU Idle calls when Linux is idle (unless this 2643 feature is turned off -- see "Do CPU IDLE calls", below). This 2644 should always save battery power, but more complicated APM features 2645 will be dependent on your BIOS implementation. You may need to turn 2646 this option off if your computer hangs at boot time when using APM 2647 support, or if it beeps continuously instead of suspending. Turn 2648 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2649 T400CDT. This is off by default since most machines do fine without 2650 this feature. 2651 2652config APM_CPU_IDLE 2653 depends on CPU_IDLE 2654 bool "Make CPU Idle calls when idle" 2655 help 2656 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2657 On some machines, this can activate improved power savings, such as 2658 a slowed CPU clock rate, when the machine is idle. These idle calls 2659 are made after the idle loop has run for some length of time (e.g., 2660 333 mS). On some machines, this will cause a hang at boot time or 2661 whenever the CPU becomes idle. (On machines with more than one CPU, 2662 this option does nothing.) 2663 2664config APM_DISPLAY_BLANK 2665 bool "Enable console blanking using APM" 2666 help 2667 Enable console blanking using the APM. Some laptops can use this to 2668 turn off the LCD backlight when the screen blanker of the Linux 2669 virtual console blanks the screen. Note that this is only used by 2670 the virtual console screen blanker, and won't turn off the backlight 2671 when using the X Window system. This also doesn't have anything to 2672 do with your VESA-compliant power-saving monitor. Further, this 2673 option doesn't work for all laptops -- it might not turn off your 2674 backlight at all, or it might print a lot of errors to the console, 2675 especially if you are using gpm. 2676 2677config APM_ALLOW_INTS 2678 bool "Allow interrupts during APM BIOS calls" 2679 help 2680 Normally we disable external interrupts while we are making calls to 2681 the APM BIOS as a measure to lessen the effects of a badly behaving 2682 BIOS implementation. The BIOS should reenable interrupts if it 2683 needs to. Unfortunately, some BIOSes do not -- especially those in 2684 many of the newer IBM Thinkpads. If you experience hangs when you 2685 suspend, try setting this to Y. Otherwise, say N. 2686 2687endif # APM 2688 2689source "drivers/cpufreq/Kconfig" 2690 2691source "drivers/cpuidle/Kconfig" 2692 2693source "drivers/idle/Kconfig" 2694 2695endmenu 2696 2697 2698menu "Bus options (PCI etc.)" 2699 2700choice 2701 prompt "PCI access mode" 2702 depends on X86_32 && PCI 2703 default PCI_GOANY 2704 help 2705 On PCI systems, the BIOS can be used to detect the PCI devices and 2706 determine their configuration. However, some old PCI motherboards 2707 have BIOS bugs and may crash if this is done. Also, some embedded 2708 PCI-based systems don't have any BIOS at all. Linux can also try to 2709 detect the PCI hardware directly without using the BIOS. 2710 2711 With this option, you can specify how Linux should detect the 2712 PCI devices. If you choose "BIOS", the BIOS will be used, 2713 if you choose "Direct", the BIOS won't be used, and if you 2714 choose "MMConfig", then PCI Express MMCONFIG will be used. 2715 If you choose "Any", the kernel will try MMCONFIG, then the 2716 direct access method and falls back to the BIOS if that doesn't 2717 work. If unsure, go with the default, which is "Any". 2718 2719config PCI_GOBIOS 2720 bool "BIOS" 2721 2722config PCI_GOMMCONFIG 2723 bool "MMConfig" 2724 2725config PCI_GODIRECT 2726 bool "Direct" 2727 2728config PCI_GOOLPC 2729 bool "OLPC XO-1" 2730 depends on OLPC 2731 2732config PCI_GOANY 2733 bool "Any" 2734 2735endchoice 2736 2737config PCI_BIOS 2738 def_bool y 2739 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2740 2741# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2742config PCI_DIRECT 2743 def_bool y 2744 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2745 2746config PCI_MMCONFIG 2747 bool "Support mmconfig PCI config space access" if X86_64 2748 default y 2749 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2750 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2751 2752config PCI_OLPC 2753 def_bool y 2754 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2755 2756config PCI_XEN 2757 def_bool y 2758 depends on PCI && XEN 2759 select SWIOTLB_XEN 2760 2761config MMCONF_FAM10H 2762 def_bool y 2763 depends on X86_64 && PCI_MMCONFIG && ACPI 2764 2765config PCI_CNB20LE_QUIRK 2766 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2767 depends on PCI 2768 help 2769 Read the PCI windows out of the CNB20LE host bridge. This allows 2770 PCI hotplug to work on systems with the CNB20LE chipset which do 2771 not have ACPI. 2772 2773 There's no public spec for this chipset, and this functionality 2774 is known to be incomplete. 2775 2776 You should say N unless you know you need this. 2777 2778config ISA_BUS 2779 bool "ISA bus support on modern systems" if EXPERT 2780 help 2781 Expose ISA bus device drivers and options available for selection and 2782 configuration. Enable this option if your target machine has an ISA 2783 bus. ISA is an older system, displaced by PCI and newer bus 2784 architectures -- if your target machine is modern, it probably does 2785 not have an ISA bus. 2786 2787 If unsure, say N. 2788 2789# x86_64 have no ISA slots, but can have ISA-style DMA. 2790config ISA_DMA_API 2791 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2792 default y 2793 help 2794 Enables ISA-style DMA support for devices requiring such controllers. 2795 If unsure, say Y. 2796 2797if X86_32 2798 2799config ISA 2800 bool "ISA support" 2801 help 2802 Find out whether you have ISA slots on your motherboard. ISA is the 2803 name of a bus system, i.e. the way the CPU talks to the other stuff 2804 inside your box. Other bus systems are PCI, EISA, MicroChannel 2805 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2806 newer boards don't support it. If you have ISA, say Y, otherwise N. 2807 2808config SCx200 2809 tristate "NatSemi SCx200 support" 2810 help 2811 This provides basic support for National Semiconductor's 2812 (now AMD's) Geode processors. The driver probes for the 2813 PCI-IDs of several on-chip devices, so its a good dependency 2814 for other scx200_* drivers. 2815 2816 If compiled as a module, the driver is named scx200. 2817 2818config SCx200HR_TIMER 2819 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2820 depends on SCx200 2821 default y 2822 help 2823 This driver provides a clocksource built upon the on-chip 2824 27MHz high-resolution timer. Its also a workaround for 2825 NSC Geode SC-1100's buggy TSC, which loses time when the 2826 processor goes idle (as is done by the scheduler). The 2827 other workaround is idle=poll boot option. 2828 2829config OLPC 2830 bool "One Laptop Per Child support" 2831 depends on !X86_PAE 2832 select GPIOLIB 2833 select OF 2834 select OF_PROMTREE 2835 select IRQ_DOMAIN 2836 select OLPC_EC 2837 help 2838 Add support for detecting the unique features of the OLPC 2839 XO hardware. 2840 2841config OLPC_XO1_PM 2842 bool "OLPC XO-1 Power Management" 2843 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2844 help 2845 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2846 2847config OLPC_XO1_RTC 2848 bool "OLPC XO-1 Real Time Clock" 2849 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2850 help 2851 Add support for the XO-1 real time clock, which can be used as a 2852 programmable wakeup source. 2853 2854config OLPC_XO1_SCI 2855 bool "OLPC XO-1 SCI extras" 2856 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2857 depends on INPUT=y 2858 select POWER_SUPPLY 2859 help 2860 Add support for SCI-based features of the OLPC XO-1 laptop: 2861 - EC-driven system wakeups 2862 - Power button 2863 - Ebook switch 2864 - Lid switch 2865 - AC adapter status updates 2866 - Battery status updates 2867 2868config OLPC_XO15_SCI 2869 bool "OLPC XO-1.5 SCI extras" 2870 depends on OLPC && ACPI 2871 select POWER_SUPPLY 2872 help 2873 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2874 - EC-driven system wakeups 2875 - AC adapter status updates 2876 - Battery status updates 2877 2878config ALIX 2879 bool "PCEngines ALIX System Support (LED setup)" 2880 select GPIOLIB 2881 help 2882 This option enables system support for the PCEngines ALIX. 2883 At present this just sets up LEDs for GPIO control on 2884 ALIX2/3/6 boards. However, other system specific setup should 2885 get added here. 2886 2887 Note: You must still enable the drivers for GPIO and LED support 2888 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2889 2890 Note: You have to set alix.force=1 for boards with Award BIOS. 2891 2892config NET5501 2893 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2894 select GPIOLIB 2895 help 2896 This option enables system support for the Soekris Engineering net5501. 2897 2898config GEOS 2899 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2900 select GPIOLIB 2901 depends on DMI 2902 help 2903 This option enables system support for the Traverse Technologies GEOS. 2904 2905config TS5500 2906 bool "Technologic Systems TS-5500 platform support" 2907 depends on MELAN 2908 select CHECK_SIGNATURE 2909 select NEW_LEDS 2910 select LEDS_CLASS 2911 help 2912 This option enables system support for the Technologic Systems TS-5500. 2913 2914endif # X86_32 2915 2916config AMD_NB 2917 def_bool y 2918 depends on CPU_SUP_AMD && PCI 2919 2920config X86_SYSFB 2921 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2922 help 2923 Firmwares often provide initial graphics framebuffers so the BIOS, 2924 bootloader or kernel can show basic video-output during boot for 2925 user-guidance and debugging. Historically, x86 used the VESA BIOS 2926 Extensions and EFI-framebuffers for this, which are mostly limited 2927 to x86. 2928 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2929 framebuffers so the new generic system-framebuffer drivers can be 2930 used on x86. If the framebuffer is not compatible with the generic 2931 modes, it is advertised as fallback platform framebuffer so legacy 2932 drivers like efifb, vesafb and uvesafb can pick it up. 2933 If this option is not selected, all system framebuffers are always 2934 marked as fallback platform framebuffers as usual. 2935 2936 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2937 not be able to pick up generic system framebuffers if this option 2938 is selected. You are highly encouraged to enable simplefb as 2939 replacement if you select this option. simplefb can correctly deal 2940 with generic system framebuffers. But you should still keep vesafb 2941 and others enabled as fallback if a system framebuffer is 2942 incompatible with simplefb. 2943 2944 If unsure, say Y. 2945 2946endmenu 2947 2948 2949menu "Binary Emulations" 2950 2951config IA32_EMULATION 2952 bool "IA32 Emulation" 2953 depends on X86_64 2954 select ARCH_WANT_OLD_COMPAT_IPC 2955 select BINFMT_ELF 2956 select COMPAT_BINFMT_ELF 2957 select COMPAT_OLD_SIGACTION 2958 help 2959 Include code to run legacy 32-bit programs under a 2960 64-bit kernel. You should likely turn this on, unless you're 2961 100% sure that you don't have any 32-bit programs left. 2962 2963config IA32_AOUT 2964 tristate "IA32 a.out support" 2965 depends on IA32_EMULATION 2966 depends on BROKEN 2967 help 2968 Support old a.out binaries in the 32bit emulation. 2969 2970config X86_X32 2971 bool "x32 ABI for 64-bit mode" 2972 depends on X86_64 2973 # llvm-objcopy does not convert x86_64 .note.gnu.property or 2974 # compressed debug sections to x86_x32 properly: 2975 # https://github.com/ClangBuiltLinux/linux/issues/514 2976 # https://github.com/ClangBuiltLinux/linux/issues/1141 2977 depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm) 2978 help 2979 Include code to run binaries for the x32 native 32-bit ABI 2980 for 64-bit processors. An x32 process gets access to the 2981 full 64-bit register file and wide data path while leaving 2982 pointers at 32 bits for smaller memory footprint. 2983 2984 You will need a recent binutils (2.22 or later) with 2985 elf32_x86_64 support enabled to compile a kernel with this 2986 option set. 2987 2988config COMPAT_32 2989 def_bool y 2990 depends on IA32_EMULATION || X86_32 2991 select HAVE_UID16 2992 select OLD_SIGSUSPEND3 2993 2994config COMPAT 2995 def_bool y 2996 depends on IA32_EMULATION || X86_X32 2997 2998if COMPAT 2999config COMPAT_FOR_U64_ALIGNMENT 3000 def_bool y 3001 3002config SYSVIPC_COMPAT 3003 def_bool y 3004 depends on SYSVIPC 3005endif 3006 3007endmenu 3008 3009 3010config HAVE_ATOMIC_IOMAP 3011 def_bool y 3012 depends on X86_32 3013 3014source "drivers/firmware/Kconfig" 3015 3016source "arch/x86/kvm/Kconfig" 3017 3018source "arch/x86/Kconfig.assembler" 3019