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 GENERIC_VDSO_32 18 select HAVE_DEBUG_STACKOVERFLOW 19 select KMAP_LOCAL 20 select MODULES_USE_ELF_REL 21 select OLD_SIGACTION 22 select ARCH_SPLIT_ARG64 23 24config X86_64 25 def_bool y 26 depends on 64BIT 27 # Options that are inherently 64-bit kernel only: 28 select ARCH_HAS_GIGANTIC_PAGE 29 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 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 select ARCH_HAS_ELFCORE_COMPAT 36 37config FORCE_DYNAMIC_FTRACE 38 def_bool y 39 depends on X86_32 40 depends on FUNCTION_TRACER 41 select DYNAMIC_FTRACE 42 help 43 We keep the static function tracing (!DYNAMIC_FTRACE) around 44 in order to test the non static function tracing in the 45 generic code, as other architectures still use it. But we 46 only need to keep it around for x86_64. No need to keep it 47 for x86_32. For x86_32, force DYNAMIC_FTRACE. 48# 49# Arch settings 50# 51# ( Note that options that are marked 'if X86_64' could in principle be 52# ported to 32-bit as well. ) 53# 54config X86 55 def_bool y 56 # 57 # Note: keep this list sorted alphabetically 58 # 59 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 60 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 61 select ARCH_32BIT_OFF_T if X86_32 62 select ARCH_CLOCKSOURCE_INIT 63 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 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_DEBUG_PAGEALLOC 98 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 99 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 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_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 118 select GENERIC_CLOCKEVENTS_MIN_ADJUST 119 select GENERIC_CMOS_UPDATE 120 select GENERIC_CPU_AUTOPROBE 121 select GENERIC_CPU_VULNERABILITIES 122 select GENERIC_EARLY_IOREMAP 123 select GENERIC_ENTRY 124 select GENERIC_FIND_FIRST_BIT 125 select GENERIC_IOMAP 126 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 127 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 128 select GENERIC_IRQ_MIGRATION if SMP 129 select GENERIC_IRQ_PROBE 130 select GENERIC_IRQ_RESERVATION_MODE 131 select GENERIC_IRQ_SHOW 132 select GENERIC_PENDING_IRQ if SMP 133 select GENERIC_PTDUMP 134 select GENERIC_SMP_IDLE_THREAD 135 select GENERIC_STRNCPY_FROM_USER 136 select GENERIC_STRNLEN_USER 137 select GENERIC_TIME_VSYSCALL 138 select GENERIC_GETTIMEOFDAY 139 select GENERIC_VDSO_TIME_NS 140 select GUP_GET_PTE_LOW_HIGH if X86_PAE 141 select HARDIRQS_SW_RESEND 142 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 143 select HAVE_ACPI_APEI if ACPI 144 select HAVE_ACPI_APEI_NMI if ACPI 145 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 146 select HAVE_ARCH_AUDITSYSCALL 147 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 148 select HAVE_ARCH_JUMP_LABEL 149 select HAVE_ARCH_JUMP_LABEL_RELATIVE 150 select HAVE_ARCH_KASAN if X86_64 151 select HAVE_ARCH_KASAN_VMALLOC if X86_64 152 select HAVE_ARCH_KGDB 153 select HAVE_ARCH_MMAP_RND_BITS if MMU 154 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 155 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 156 select HAVE_ARCH_PREL32_RELOCATIONS 157 select HAVE_ARCH_SECCOMP_FILTER 158 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 159 select HAVE_ARCH_STACKLEAK 160 select HAVE_ARCH_TRACEHOOK 161 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 162 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 163 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 164 select HAVE_ARCH_VMAP_STACK if X86_64 165 select HAVE_ARCH_WITHIN_STACK_FRAMES 166 select HAVE_ASM_MODVERSIONS 167 select HAVE_CMPXCHG_DOUBLE 168 select HAVE_CMPXCHG_LOCAL 169 select HAVE_CONTEXT_TRACKING if X86_64 170 select HAVE_CONTEXT_TRACKING_OFFSTACK if HAVE_CONTEXT_TRACKING 171 select HAVE_C_RECORDMCOUNT 172 select HAVE_DEBUG_KMEMLEAK 173 select HAVE_DMA_CONTIGUOUS 174 select HAVE_DYNAMIC_FTRACE 175 select HAVE_DYNAMIC_FTRACE_WITH_REGS 176 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 177 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 178 select HAVE_EBPF_JIT 179 select HAVE_EFFICIENT_UNALIGNED_ACCESS 180 select HAVE_EISA 181 select HAVE_EXIT_THREAD 182 select HAVE_FAST_GUP 183 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 184 select HAVE_FTRACE_MCOUNT_RECORD 185 select HAVE_FUNCTION_GRAPH_TRACER 186 select HAVE_FUNCTION_TRACER 187 select HAVE_GCC_PLUGINS 188 select HAVE_HW_BREAKPOINT 189 select HAVE_IDE 190 select HAVE_IOREMAP_PROT 191 select HAVE_IRQ_TIME_ACCOUNTING 192 select HAVE_KERNEL_BZIP2 193 select HAVE_KERNEL_GZIP 194 select HAVE_KERNEL_LZ4 195 select HAVE_KERNEL_LZMA 196 select HAVE_KERNEL_LZO 197 select HAVE_KERNEL_XZ 198 select HAVE_KERNEL_ZSTD 199 select HAVE_KPROBES 200 select HAVE_KPROBES_ON_FTRACE 201 select HAVE_FUNCTION_ERROR_INJECTION 202 select HAVE_KRETPROBES 203 select HAVE_KVM 204 select HAVE_LIVEPATCH if X86_64 205 select HAVE_MIXED_BREAKPOINTS_REGS 206 select HAVE_MOD_ARCH_SPECIFIC 207 select HAVE_MOVE_PMD 208 select HAVE_MOVE_PUD 209 select HAVE_NMI 210 select HAVE_OPTPROBES 211 select HAVE_PCSPKR_PLATFORM 212 select HAVE_PERF_EVENTS 213 select HAVE_PERF_EVENTS_NMI 214 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 215 select HAVE_PCI 216 select HAVE_PERF_REGS 217 select HAVE_PERF_USER_STACK_DUMP 218 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 219 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 220 select HAVE_REGS_AND_STACK_ACCESS_API 221 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 222 select HAVE_FUNCTION_ARG_ACCESS_API 223 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 224 select HAVE_STACK_VALIDATION if X86_64 225 select HAVE_STATIC_CALL 226 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION 227 select HAVE_PREEMPT_DYNAMIC 228 select HAVE_RSEQ 229 select HAVE_SYSCALL_TRACEPOINTS 230 select HAVE_UNSTABLE_SCHED_CLOCK 231 select HAVE_USER_RETURN_NOTIFIER 232 select HAVE_GENERIC_VDSO 233 select HOTPLUG_SMT if SMP 234 select IRQ_FORCED_THREADING 235 select NEED_SG_DMA_LENGTH 236 select PCI_DOMAINS if PCI 237 select PCI_LOCKLESS_CONFIG if PCI 238 select PERF_EVENTS 239 select RTC_LIB 240 select RTC_MC146818_LIB 241 select SPARSE_IRQ 242 select SRCU 243 select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE) 244 select SYSCTL_EXCEPTION_TRACE 245 select THREAD_INFO_IN_TASK 246 select USER_STACKTRACE_SUPPORT 247 select VIRT_TO_BUS 248 select HAVE_ARCH_KCSAN if X86_64 249 select X86_FEATURE_NAMES if PROC_FS 250 select PROC_PID_ARCH_STATUS if PROC_FS 251 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 252 253config INSTRUCTION_DECODER 254 def_bool y 255 depends on KPROBES || PERF_EVENTS || UPROBES 256 257config OUTPUT_FORMAT 258 string 259 default "elf32-i386" if X86_32 260 default "elf64-x86-64" if X86_64 261 262config LOCKDEP_SUPPORT 263 def_bool y 264 265config STACKTRACE_SUPPORT 266 def_bool y 267 268config MMU 269 def_bool y 270 271config ARCH_MMAP_RND_BITS_MIN 272 default 28 if 64BIT 273 default 8 274 275config ARCH_MMAP_RND_BITS_MAX 276 default 32 if 64BIT 277 default 16 278 279config ARCH_MMAP_RND_COMPAT_BITS_MIN 280 default 8 281 282config ARCH_MMAP_RND_COMPAT_BITS_MAX 283 default 16 284 285config SBUS 286 bool 287 288config GENERIC_ISA_DMA 289 def_bool y 290 depends on ISA_DMA_API 291 292config GENERIC_BUG 293 def_bool y 294 depends on BUG 295 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 296 297config GENERIC_BUG_RELATIVE_POINTERS 298 bool 299 300config ARCH_MAY_HAVE_PC_FDC 301 def_bool y 302 depends on ISA_DMA_API 303 304config GENERIC_CALIBRATE_DELAY 305 def_bool y 306 307config ARCH_HAS_CPU_RELAX 308 def_bool y 309 310config ARCH_HAS_CACHE_LINE_SIZE 311 def_bool y 312 313config ARCH_HAS_FILTER_PGPROT 314 def_bool y 315 316config HAVE_SETUP_PER_CPU_AREA 317 def_bool y 318 319config NEED_PER_CPU_EMBED_FIRST_CHUNK 320 def_bool y 321 322config NEED_PER_CPU_PAGE_FIRST_CHUNK 323 def_bool y 324 325config ARCH_HIBERNATION_POSSIBLE 326 def_bool y 327 328config ARCH_SUSPEND_POSSIBLE 329 def_bool y 330 331config ARCH_WANT_GENERAL_HUGETLB 332 def_bool y 333 334config ZONE_DMA32 335 def_bool y if X86_64 336 337config AUDIT_ARCH 338 def_bool y if X86_64 339 340config KASAN_SHADOW_OFFSET 341 hex 342 depends on KASAN 343 default 0xdffffc0000000000 344 345config HAVE_INTEL_TXT 346 def_bool y 347 depends on INTEL_IOMMU && ACPI 348 349config X86_32_SMP 350 def_bool y 351 depends on X86_32 && SMP 352 353config X86_64_SMP 354 def_bool y 355 depends on X86_64 && SMP 356 357config X86_32_LAZY_GS 358 def_bool y 359 depends on X86_32 && !STACKPROTECTOR 360 361config ARCH_SUPPORTS_UPROBES 362 def_bool y 363 364config FIX_EARLYCON_MEM 365 def_bool y 366 367config DYNAMIC_PHYSICAL_MASK 368 bool 369 370config PGTABLE_LEVELS 371 int 372 default 5 if X86_5LEVEL 373 default 4 if X86_64 374 default 3 if X86_PAE 375 default 2 376 377config CC_HAS_SANE_STACKPROTECTOR 378 bool 379 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 380 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 381 help 382 We have to make sure stack protector is unconditionally disabled if 383 the compiler produces broken code. 384 385menu "Processor type and features" 386 387config ZONE_DMA 388 bool "DMA memory allocation support" if EXPERT 389 default y 390 help 391 DMA memory allocation support allows devices with less than 32-bit 392 addressing to allocate within the first 16MB of address space. 393 Disable if no such devices will be used. 394 395 If unsure, say Y. 396 397config SMP 398 bool "Symmetric multi-processing support" 399 help 400 This enables support for systems with more than one CPU. If you have 401 a system with only one CPU, say N. If you have a system with more 402 than one CPU, say Y. 403 404 If you say N here, the kernel will run on uni- and multiprocessor 405 machines, but will use only one CPU of a multiprocessor machine. If 406 you say Y here, the kernel will run on many, but not all, 407 uniprocessor machines. On a uniprocessor machine, the kernel 408 will run faster if you say N here. 409 410 Note that if you say Y here and choose architecture "586" or 411 "Pentium" under "Processor family", the kernel will not work on 486 412 architectures. Similarly, multiprocessor kernels for the "PPro" 413 architecture may not work on all Pentium based boards. 414 415 People using multiprocessor machines who say Y here should also say 416 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 417 Management" code will be disabled if you say Y here. 418 419 See also <file:Documentation/x86/i386/IO-APIC.rst>, 420 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 421 <http://www.tldp.org/docs.html#howto>. 422 423 If you don't know what to do here, say N. 424 425config X86_FEATURE_NAMES 426 bool "Processor feature human-readable names" if EMBEDDED 427 default y 428 help 429 This option compiles in a table of x86 feature bits and corresponding 430 names. This is required to support /proc/cpuinfo and a few kernel 431 messages. You can disable this to save space, at the expense of 432 making those few kernel messages show numeric feature bits instead. 433 434 If in doubt, say Y. 435 436config X86_X2APIC 437 bool "Support x2apic" 438 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 439 help 440 This enables x2apic support on CPUs that have this feature. 441 442 This allows 32-bit apic IDs (so it can support very large systems), 443 and accesses the local apic via MSRs not via mmio. 444 445 If you don't know what to do here, say N. 446 447config X86_MPPARSE 448 bool "Enable MPS table" if ACPI || SFI 449 default y 450 depends on X86_LOCAL_APIC 451 help 452 For old smp systems that do not have proper acpi support. Newer systems 453 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 454 455config GOLDFISH 456 def_bool y 457 depends on X86_GOLDFISH 458 459config RETPOLINE 460 bool "Avoid speculative indirect branches in kernel" 461 default y 462 help 463 Compile kernel with the retpoline compiler options to guard against 464 kernel-to-user data leaks by avoiding speculative indirect 465 branches. Requires a compiler with -mindirect-branch=thunk-extern 466 support for full protection. The kernel may run slower. 467 468config X86_CPU_RESCTRL 469 bool "x86 CPU resource control support" 470 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 471 select KERNFS 472 select PROC_CPU_RESCTRL if PROC_FS 473 help 474 Enable x86 CPU resource control support. 475 476 Provide support for the allocation and monitoring of system resources 477 usage by the CPU. 478 479 Intel calls this Intel Resource Director Technology 480 (Intel(R) RDT). More information about RDT can be found in the 481 Intel x86 Architecture Software Developer Manual. 482 483 AMD calls this AMD Platform Quality of Service (AMD QoS). 484 More information about AMD QoS can be found in the AMD64 Technology 485 Platform Quality of Service Extensions manual. 486 487 Say N if unsure. 488 489if X86_32 490config X86_BIGSMP 491 bool "Support for big SMP systems with more than 8 CPUs" 492 depends on SMP 493 help 494 This option is needed for the systems that have more than 8 CPUs. 495 496config X86_EXTENDED_PLATFORM 497 bool "Support for extended (non-PC) x86 platforms" 498 default y 499 help 500 If you disable this option then the kernel will only support 501 standard PC platforms. (which covers the vast majority of 502 systems out there.) 503 504 If you enable this option then you'll be able to select support 505 for the following (non-PC) 32 bit x86 platforms: 506 Goldfish (Android emulator) 507 AMD Elan 508 RDC R-321x SoC 509 SGI 320/540 (Visual Workstation) 510 STA2X11-based (e.g. Northville) 511 Moorestown MID devices 512 513 If you have one of these systems, or if you want to build a 514 generic distribution kernel, say Y here - otherwise say N. 515endif 516 517if X86_64 518config X86_EXTENDED_PLATFORM 519 bool "Support for extended (non-PC) x86 platforms" 520 default y 521 help 522 If you disable this option then the kernel will only support 523 standard PC platforms. (which covers the vast majority of 524 systems out there.) 525 526 If you enable this option then you'll be able to select support 527 for the following (non-PC) 64 bit x86 platforms: 528 Numascale NumaChip 529 ScaleMP vSMP 530 SGI Ultraviolet 531 532 If you have one of these systems, or if you want to build a 533 generic distribution kernel, say Y here - otherwise say N. 534endif 535# This is an alphabetically sorted list of 64 bit extended platforms 536# Please maintain the alphabetic order if and when there are additions 537config X86_NUMACHIP 538 bool "Numascale NumaChip" 539 depends on X86_64 540 depends on X86_EXTENDED_PLATFORM 541 depends on NUMA 542 depends on SMP 543 depends on X86_X2APIC 544 depends on PCI_MMCONFIG 545 help 546 Adds support for Numascale NumaChip large-SMP systems. Needed to 547 enable more than ~168 cores. 548 If you don't have one of these, you should say N here. 549 550config X86_VSMP 551 bool "ScaleMP vSMP" 552 select HYPERVISOR_GUEST 553 select PARAVIRT 554 depends on X86_64 && PCI 555 depends on X86_EXTENDED_PLATFORM 556 depends on SMP 557 help 558 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 559 supposed to run on these EM64T-based machines. Only choose this option 560 if you have one of these machines. 561 562config X86_UV 563 bool "SGI Ultraviolet" 564 depends on X86_64 565 depends on X86_EXTENDED_PLATFORM 566 depends on NUMA 567 depends on EFI 568 depends on X86_X2APIC 569 depends on PCI 570 help 571 This option is needed in order to support SGI Ultraviolet systems. 572 If you don't have one of these, you should say N here. 573 574# Following is an alphabetically sorted list of 32 bit extended platforms 575# Please maintain the alphabetic order if and when there are additions 576 577config X86_GOLDFISH 578 bool "Goldfish (Virtual Platform)" 579 depends on X86_EXTENDED_PLATFORM 580 help 581 Enable support for the Goldfish virtual platform used primarily 582 for Android development. Unless you are building for the Android 583 Goldfish emulator say N here. 584 585config X86_INTEL_CE 586 bool "CE4100 TV platform" 587 depends on PCI 588 depends on PCI_GODIRECT 589 depends on X86_IO_APIC 590 depends on X86_32 591 depends on X86_EXTENDED_PLATFORM 592 select X86_REBOOTFIXUPS 593 select OF 594 select OF_EARLY_FLATTREE 595 help 596 Select for the Intel CE media processor (CE4100) SOC. 597 This option compiles in support for the CE4100 SOC for settop 598 boxes and media devices. 599 600config X86_INTEL_MID 601 bool "Intel MID platform support" 602 depends on X86_EXTENDED_PLATFORM 603 depends on X86_PLATFORM_DEVICES 604 depends on PCI 605 depends on X86_64 || (PCI_GOANY && X86_32) 606 depends on X86_IO_APIC 607 select SFI 608 select I2C 609 select DW_APB_TIMER 610 select APB_TIMER 611 select INTEL_SCU_PCI 612 select MFD_INTEL_MSIC 613 help 614 Select to build a kernel capable of supporting Intel MID (Mobile 615 Internet Device) platform systems which do not have the PCI legacy 616 interfaces. If you are building for a PC class system say N here. 617 618 Intel MID platforms are based on an Intel processor and chipset which 619 consume less power than most of the x86 derivatives. 620 621config X86_INTEL_QUARK 622 bool "Intel Quark platform support" 623 depends on X86_32 624 depends on X86_EXTENDED_PLATFORM 625 depends on X86_PLATFORM_DEVICES 626 depends on X86_TSC 627 depends on PCI 628 depends on PCI_GOANY 629 depends on X86_IO_APIC 630 select IOSF_MBI 631 select INTEL_IMR 632 select COMMON_CLK 633 help 634 Select to include support for Quark X1000 SoC. 635 Say Y here if you have a Quark based system such as the Arduino 636 compatible Intel Galileo. 637 638config X86_INTEL_LPSS 639 bool "Intel Low Power Subsystem Support" 640 depends on X86 && ACPI && PCI 641 select COMMON_CLK 642 select PINCTRL 643 select IOSF_MBI 644 help 645 Select to build support for Intel Low Power Subsystem such as 646 found on Intel Lynxpoint PCH. Selecting this option enables 647 things like clock tree (common clock framework) and pincontrol 648 which are needed by the LPSS peripheral drivers. 649 650config X86_AMD_PLATFORM_DEVICE 651 bool "AMD ACPI2Platform devices support" 652 depends on ACPI 653 select COMMON_CLK 654 select PINCTRL 655 help 656 Select to interpret AMD specific ACPI device to platform device 657 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 658 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 659 implemented under PINCTRL subsystem. 660 661config IOSF_MBI 662 tristate "Intel SoC IOSF Sideband support for SoC platforms" 663 depends on PCI 664 help 665 This option enables sideband register access support for Intel SoC 666 platforms. On these platforms the IOSF sideband is used in lieu of 667 MSR's for some register accesses, mostly but not limited to thermal 668 and power. Drivers may query the availability of this device to 669 determine if they need the sideband in order to work on these 670 platforms. The sideband is available on the following SoC products. 671 This list is not meant to be exclusive. 672 - BayTrail 673 - Braswell 674 - Quark 675 676 You should say Y if you are running a kernel on one of these SoC's. 677 678config IOSF_MBI_DEBUG 679 bool "Enable IOSF sideband access through debugfs" 680 depends on IOSF_MBI && DEBUG_FS 681 help 682 Select this option to expose the IOSF sideband access registers (MCR, 683 MDR, MCRX) through debugfs to write and read register information from 684 different units on the SoC. This is most useful for obtaining device 685 state information for debug and analysis. As this is a general access 686 mechanism, users of this option would have specific knowledge of the 687 device they want to access. 688 689 If you don't require the option or are in doubt, say N. 690 691config X86_RDC321X 692 bool "RDC R-321x SoC" 693 depends on X86_32 694 depends on X86_EXTENDED_PLATFORM 695 select M486 696 select X86_REBOOTFIXUPS 697 help 698 This option is needed for RDC R-321x system-on-chip, also known 699 as R-8610-(G). 700 If you don't have one of these chips, you should say N here. 701 702config X86_32_NON_STANDARD 703 bool "Support non-standard 32-bit SMP architectures" 704 depends on X86_32 && SMP 705 depends on X86_EXTENDED_PLATFORM 706 help 707 This option compiles in the bigsmp and STA2X11 default 708 subarchitectures. It is intended for a generic binary 709 kernel. If you select them all, kernel will probe it one by 710 one and will fallback to default. 711 712# Alphabetically sorted list of Non standard 32 bit platforms 713 714config X86_SUPPORTS_MEMORY_FAILURE 715 def_bool y 716 # MCE code calls memory_failure(): 717 depends on X86_MCE 718 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 719 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 720 depends on X86_64 || !SPARSEMEM 721 select ARCH_SUPPORTS_MEMORY_FAILURE 722 723config STA2X11 724 bool "STA2X11 Companion Chip Support" 725 depends on X86_32_NON_STANDARD && PCI 726 select SWIOTLB 727 select MFD_STA2X11 728 select GPIOLIB 729 help 730 This adds support for boards based on the STA2X11 IO-Hub, 731 a.k.a. "ConneXt". The chip is used in place of the standard 732 PC chipset, so all "standard" peripherals are missing. If this 733 option is selected the kernel will still be able to boot on 734 standard PC machines. 735 736config X86_32_IRIS 737 tristate "Eurobraille/Iris poweroff module" 738 depends on X86_32 739 help 740 The Iris machines from EuroBraille do not have APM or ACPI support 741 to shut themselves down properly. A special I/O sequence is 742 needed to do so, which is what this module does at 743 kernel shutdown. 744 745 This is only for Iris machines from EuroBraille. 746 747 If unused, say N. 748 749config SCHED_OMIT_FRAME_POINTER 750 def_bool y 751 prompt "Single-depth WCHAN output" 752 depends on X86 753 help 754 Calculate simpler /proc/<PID>/wchan values. If this option 755 is disabled then wchan values will recurse back to the 756 caller function. This provides more accurate wchan values, 757 at the expense of slightly more scheduling overhead. 758 759 If in doubt, say "Y". 760 761menuconfig HYPERVISOR_GUEST 762 bool "Linux guest support" 763 help 764 Say Y here to enable options for running Linux under various hyper- 765 visors. This option enables basic hypervisor detection and platform 766 setup. 767 768 If you say N, all options in this submenu will be skipped and 769 disabled, and Linux guest support won't be built in. 770 771if HYPERVISOR_GUEST 772 773config PARAVIRT 774 bool "Enable paravirtualization code" 775 help 776 This changes the kernel so it can modify itself when it is run 777 under a hypervisor, potentially improving performance significantly 778 over full virtualization. However, when run without a hypervisor 779 the kernel is theoretically slower and slightly larger. 780 781config PARAVIRT_XXL 782 bool 783 784config PARAVIRT_DEBUG 785 bool "paravirt-ops debugging" 786 depends on PARAVIRT && DEBUG_KERNEL 787 help 788 Enable to debug paravirt_ops internals. Specifically, BUG if 789 a paravirt_op is missing when it is called. 790 791config PARAVIRT_SPINLOCKS 792 bool "Paravirtualization layer for spinlocks" 793 depends on PARAVIRT && SMP 794 help 795 Paravirtualized spinlocks allow a pvops backend to replace the 796 spinlock implementation with something virtualization-friendly 797 (for example, block the virtual CPU rather than spinning). 798 799 It has a minimal impact on native kernels and gives a nice performance 800 benefit on paravirtualized KVM / Xen kernels. 801 802 If you are unsure how to answer this question, answer Y. 803 804config X86_HV_CALLBACK_VECTOR 805 def_bool n 806 807source "arch/x86/xen/Kconfig" 808 809config KVM_GUEST 810 bool "KVM Guest support (including kvmclock)" 811 depends on PARAVIRT 812 select PARAVIRT_CLOCK 813 select ARCH_CPUIDLE_HALTPOLL 814 select X86_HV_CALLBACK_VECTOR 815 default y 816 help 817 This option enables various optimizations for running under the KVM 818 hypervisor. It includes a paravirtualized clock, so that instead 819 of relying on a PIT (or probably other) emulation by the 820 underlying device model, the host provides the guest with 821 timing infrastructure such as time of day, and system time 822 823config ARCH_CPUIDLE_HALTPOLL 824 def_bool n 825 prompt "Disable host haltpoll when loading haltpoll driver" 826 help 827 If virtualized under KVM, disable host haltpoll. 828 829config PVH 830 bool "Support for running PVH guests" 831 help 832 This option enables the PVH entry point for guest virtual machines 833 as specified in the x86/HVM direct boot ABI. 834 835config PARAVIRT_TIME_ACCOUNTING 836 bool "Paravirtual steal time accounting" 837 depends on PARAVIRT 838 help 839 Select this option to enable fine granularity task steal time 840 accounting. Time spent executing other tasks in parallel with 841 the current vCPU is discounted from the vCPU power. To account for 842 that, there can be a small performance impact. 843 844 If in doubt, say N here. 845 846config PARAVIRT_CLOCK 847 bool 848 849config JAILHOUSE_GUEST 850 bool "Jailhouse non-root cell support" 851 depends on X86_64 && PCI 852 select X86_PM_TIMER 853 help 854 This option allows to run Linux as guest in a Jailhouse non-root 855 cell. You can leave this option disabled if you only want to start 856 Jailhouse and run Linux afterwards in the root cell. 857 858config ACRN_GUEST 859 bool "ACRN Guest support" 860 depends on X86_64 861 select X86_HV_CALLBACK_VECTOR 862 help 863 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 864 a flexible, lightweight reference open-source hypervisor, built with 865 real-time and safety-criticality in mind. It is built for embedded 866 IOT with small footprint and real-time features. More details can be 867 found in https://projectacrn.org/. 868 869endif #HYPERVISOR_GUEST 870 871source "arch/x86/Kconfig.cpu" 872 873config HPET_TIMER 874 def_bool X86_64 875 prompt "HPET Timer Support" if X86_32 876 help 877 Use the IA-PC HPET (High Precision Event Timer) to manage 878 time in preference to the PIT and RTC, if a HPET is 879 present. 880 HPET is the next generation timer replacing legacy 8254s. 881 The HPET provides a stable time base on SMP 882 systems, unlike the TSC, but it is more expensive to access, 883 as it is off-chip. The interface used is documented 884 in the HPET spec, revision 1. 885 886 You can safely choose Y here. However, HPET will only be 887 activated if the platform and the BIOS support this feature. 888 Otherwise the 8254 will be used for timing services. 889 890 Choose N to continue using the legacy 8254 timer. 891 892config HPET_EMULATE_RTC 893 def_bool y 894 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 895 896config APB_TIMER 897 def_bool y if X86_INTEL_MID 898 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 899 select DW_APB_TIMER 900 depends on X86_INTEL_MID && SFI 901 help 902 APB timer is the replacement for 8254, HPET on X86 MID platforms. 903 The APBT provides a stable time base on SMP 904 systems, unlike the TSC, but it is more expensive to access, 905 as it is off-chip. APB timers are always running regardless of CPU 906 C states, they are used as per CPU clockevent device when possible. 907 908# Mark as expert because too many people got it wrong. 909# The code disables itself when not needed. 910config DMI 911 default y 912 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 913 bool "Enable DMI scanning" if EXPERT 914 help 915 Enabled scanning of DMI to identify machine quirks. Say Y 916 here unless you have verified that your setup is not 917 affected by entries in the DMI blacklist. Required by PNP 918 BIOS code. 919 920config GART_IOMMU 921 bool "Old AMD GART IOMMU support" 922 select DMA_OPS 923 select IOMMU_HELPER 924 select SWIOTLB 925 depends on X86_64 && PCI && AMD_NB 926 help 927 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 928 GART based hardware IOMMUs. 929 930 The GART supports full DMA access for devices with 32-bit access 931 limitations, on systems with more than 3 GB. This is usually needed 932 for USB, sound, many IDE/SATA chipsets and some other devices. 933 934 Newer systems typically have a modern AMD IOMMU, supported via 935 the CONFIG_AMD_IOMMU=y config option. 936 937 In normal configurations this driver is only active when needed: 938 there's more than 3 GB of memory and the system contains a 939 32-bit limited device. 940 941 If unsure, say Y. 942 943config MAXSMP 944 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 945 depends on X86_64 && SMP && DEBUG_KERNEL 946 select CPUMASK_OFFSTACK 947 help 948 Enable maximum number of CPUS and NUMA Nodes for this architecture. 949 If unsure, say N. 950 951# 952# The maximum number of CPUs supported: 953# 954# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 955# and which can be configured interactively in the 956# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 957# 958# The ranges are different on 32-bit and 64-bit kernels, depending on 959# hardware capabilities and scalability features of the kernel. 960# 961# ( If MAXSMP is enabled we just use the highest possible value and disable 962# interactive configuration. ) 963# 964 965config NR_CPUS_RANGE_BEGIN 966 int 967 default NR_CPUS_RANGE_END if MAXSMP 968 default 1 if !SMP 969 default 2 970 971config NR_CPUS_RANGE_END 972 int 973 depends on X86_32 974 default 64 if SMP && X86_BIGSMP 975 default 8 if SMP && !X86_BIGSMP 976 default 1 if !SMP 977 978config NR_CPUS_RANGE_END 979 int 980 depends on X86_64 981 default 8192 if SMP && CPUMASK_OFFSTACK 982 default 512 if SMP && !CPUMASK_OFFSTACK 983 default 1 if !SMP 984 985config NR_CPUS_DEFAULT 986 int 987 depends on X86_32 988 default 32 if X86_BIGSMP 989 default 8 if SMP 990 default 1 if !SMP 991 992config NR_CPUS_DEFAULT 993 int 994 depends on X86_64 995 default 8192 if MAXSMP 996 default 64 if SMP 997 default 1 if !SMP 998 999config NR_CPUS 1000 int "Maximum number of CPUs" if SMP && !MAXSMP 1001 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1002 default NR_CPUS_DEFAULT 1003 help 1004 This allows you to specify the maximum number of CPUs which this 1005 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1006 supported value is 8192, otherwise the maximum value is 512. The 1007 minimum value which makes sense is 2. 1008 1009 This is purely to save memory: each supported CPU adds about 8KB 1010 to the kernel image. 1011 1012config SCHED_SMT 1013 def_bool y if SMP 1014 1015config SCHED_MC 1016 def_bool y 1017 prompt "Multi-core scheduler support" 1018 depends on SMP 1019 help 1020 Multi-core scheduler support improves the CPU scheduler's decision 1021 making when dealing with multi-core CPU chips at a cost of slightly 1022 increased overhead in some places. If unsure say N here. 1023 1024config SCHED_MC_PRIO 1025 bool "CPU core priorities scheduler support" 1026 depends on SCHED_MC && CPU_SUP_INTEL 1027 select X86_INTEL_PSTATE 1028 select CPU_FREQ 1029 default y 1030 help 1031 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1032 core ordering determined at manufacturing time, which allows 1033 certain cores to reach higher turbo frequencies (when running 1034 single threaded workloads) than others. 1035 1036 Enabling this kernel feature teaches the scheduler about 1037 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1038 scheduler's CPU selection logic accordingly, so that higher 1039 overall system performance can be achieved. 1040 1041 This feature will have no effect on CPUs without this feature. 1042 1043 If unsure say Y here. 1044 1045config UP_LATE_INIT 1046 def_bool y 1047 depends on !SMP && X86_LOCAL_APIC 1048 1049config X86_UP_APIC 1050 bool "Local APIC support on uniprocessors" if !PCI_MSI 1051 default PCI_MSI 1052 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1053 help 1054 A local APIC (Advanced Programmable Interrupt Controller) is an 1055 integrated interrupt controller in the CPU. If you have a single-CPU 1056 system which has a processor with a local APIC, you can say Y here to 1057 enable and use it. If you say Y here even though your machine doesn't 1058 have a local APIC, then the kernel will still run with no slowdown at 1059 all. The local APIC supports CPU-generated self-interrupts (timer, 1060 performance counters), and the NMI watchdog which detects hard 1061 lockups. 1062 1063config X86_UP_IOAPIC 1064 bool "IO-APIC support on uniprocessors" 1065 depends on X86_UP_APIC 1066 help 1067 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1068 SMP-capable replacement for PC-style interrupt controllers. Most 1069 SMP systems and many recent uniprocessor systems have one. 1070 1071 If you have a single-CPU system with an IO-APIC, you can say Y here 1072 to use it. If you say Y here even though your machine doesn't have 1073 an IO-APIC, then the kernel will still run with no slowdown at all. 1074 1075config X86_LOCAL_APIC 1076 def_bool y 1077 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1078 select IRQ_DOMAIN_HIERARCHY 1079 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1080 1081config X86_IO_APIC 1082 def_bool y 1083 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1084 1085config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1086 bool "Reroute for broken boot IRQs" 1087 depends on X86_IO_APIC 1088 help 1089 This option enables a workaround that fixes a source of 1090 spurious interrupts. This is recommended when threaded 1091 interrupt handling is used on systems where the generation of 1092 superfluous "boot interrupts" cannot be disabled. 1093 1094 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1095 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1096 kernel does during interrupt handling). On chipsets where this 1097 boot IRQ generation cannot be disabled, this workaround keeps 1098 the original IRQ line masked so that only the equivalent "boot 1099 IRQ" is delivered to the CPUs. The workaround also tells the 1100 kernel to set up the IRQ handler on the boot IRQ line. In this 1101 way only one interrupt is delivered to the kernel. Otherwise 1102 the spurious second interrupt may cause the kernel to bring 1103 down (vital) interrupt lines. 1104 1105 Only affects "broken" chipsets. Interrupt sharing may be 1106 increased on these systems. 1107 1108config X86_MCE 1109 bool "Machine Check / overheating reporting" 1110 select GENERIC_ALLOCATOR 1111 default y 1112 help 1113 Machine Check support allows the processor to notify the 1114 kernel if it detects a problem (e.g. overheating, data corruption). 1115 The action the kernel takes depends on the severity of the problem, 1116 ranging from warning messages to halting the machine. 1117 1118config X86_MCELOG_LEGACY 1119 bool "Support for deprecated /dev/mcelog character device" 1120 depends on X86_MCE 1121 help 1122 Enable support for /dev/mcelog which is needed by the old mcelog 1123 userspace logging daemon. Consider switching to the new generation 1124 rasdaemon solution. 1125 1126config X86_MCE_INTEL 1127 def_bool y 1128 prompt "Intel MCE features" 1129 depends on X86_MCE && X86_LOCAL_APIC 1130 help 1131 Additional support for intel specific MCE features such as 1132 the thermal monitor. 1133 1134config X86_MCE_AMD 1135 def_bool y 1136 prompt "AMD MCE features" 1137 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1138 help 1139 Additional support for AMD specific MCE features such as 1140 the DRAM Error Threshold. 1141 1142config X86_ANCIENT_MCE 1143 bool "Support for old Pentium 5 / WinChip machine checks" 1144 depends on X86_32 && X86_MCE 1145 help 1146 Include support for machine check handling on old Pentium 5 or WinChip 1147 systems. These typically need to be enabled explicitly on the command 1148 line. 1149 1150config X86_MCE_THRESHOLD 1151 depends on X86_MCE_AMD || X86_MCE_INTEL 1152 def_bool y 1153 1154config X86_MCE_INJECT 1155 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1156 tristate "Machine check injector support" 1157 help 1158 Provide support for injecting machine checks for testing purposes. 1159 If you don't know what a machine check is and you don't do kernel 1160 QA it is safe to say n. 1161 1162source "arch/x86/events/Kconfig" 1163 1164config X86_LEGACY_VM86 1165 bool "Legacy VM86 support" 1166 depends on X86_32 1167 help 1168 This option allows user programs to put the CPU into V8086 1169 mode, which is an 80286-era approximation of 16-bit real mode. 1170 1171 Some very old versions of X and/or vbetool require this option 1172 for user mode setting. Similarly, DOSEMU will use it if 1173 available to accelerate real mode DOS programs. However, any 1174 recent version of DOSEMU, X, or vbetool should be fully 1175 functional even without kernel VM86 support, as they will all 1176 fall back to software emulation. Nevertheless, if you are using 1177 a 16-bit DOS program where 16-bit performance matters, vm86 1178 mode might be faster than emulation and you might want to 1179 enable this option. 1180 1181 Note that any app that works on a 64-bit kernel is unlikely to 1182 need this option, as 64-bit kernels don't, and can't, support 1183 V8086 mode. This option is also unrelated to 16-bit protected 1184 mode and is not needed to run most 16-bit programs under Wine. 1185 1186 Enabling this option increases the complexity of the kernel 1187 and slows down exception handling a tiny bit. 1188 1189 If unsure, say N here. 1190 1191config VM86 1192 bool 1193 default X86_LEGACY_VM86 1194 1195config X86_16BIT 1196 bool "Enable support for 16-bit segments" if EXPERT 1197 default y 1198 depends on MODIFY_LDT_SYSCALL 1199 help 1200 This option is required by programs like Wine to run 16-bit 1201 protected mode legacy code on x86 processors. Disabling 1202 this option saves about 300 bytes on i386, or around 6K text 1203 plus 16K runtime memory on x86-64, 1204 1205config X86_ESPFIX32 1206 def_bool y 1207 depends on X86_16BIT && X86_32 1208 1209config X86_ESPFIX64 1210 def_bool y 1211 depends on X86_16BIT && X86_64 1212 1213config X86_VSYSCALL_EMULATION 1214 bool "Enable vsyscall emulation" if EXPERT 1215 default y 1216 depends on X86_64 1217 help 1218 This enables emulation of the legacy vsyscall page. Disabling 1219 it is roughly equivalent to booting with vsyscall=none, except 1220 that it will also disable the helpful warning if a program 1221 tries to use a vsyscall. With this option set to N, offending 1222 programs will just segfault, citing addresses of the form 1223 0xffffffffff600?00. 1224 1225 This option is required by many programs built before 2013, and 1226 care should be used even with newer programs if set to N. 1227 1228 Disabling this option saves about 7K of kernel size and 1229 possibly 4K of additional runtime pagetable memory. 1230 1231config X86_IOPL_IOPERM 1232 bool "IOPERM and IOPL Emulation" 1233 default y 1234 help 1235 This enables the ioperm() and iopl() syscalls which are necessary 1236 for legacy applications. 1237 1238 Legacy IOPL support is an overbroad mechanism which allows user 1239 space aside of accessing all 65536 I/O ports also to disable 1240 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1241 capabilities and permission from potentially active security 1242 modules. 1243 1244 The emulation restricts the functionality of the syscall to 1245 only allowing the full range I/O port access, but prevents the 1246 ability to disable interrupts from user space which would be 1247 granted if the hardware IOPL mechanism would be used. 1248 1249config TOSHIBA 1250 tristate "Toshiba Laptop support" 1251 depends on X86_32 1252 help 1253 This adds a driver to safely access the System Management Mode of 1254 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1255 not work on models with a Phoenix BIOS. The System Management Mode 1256 is used to set the BIOS and power saving options on Toshiba portables. 1257 1258 For information on utilities to make use of this driver see the 1259 Toshiba Linux utilities web site at: 1260 <http://www.buzzard.org.uk/toshiba/>. 1261 1262 Say Y if you intend to run this kernel on a Toshiba portable. 1263 Say N otherwise. 1264 1265config I8K 1266 tristate "Dell i8k legacy laptop support" 1267 select HWMON 1268 select SENSORS_DELL_SMM 1269 help 1270 This option enables legacy /proc/i8k userspace interface in hwmon 1271 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1272 temperature and allows controlling fan speeds of Dell laptops via 1273 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1274 it reports also power and hotkey status. For fan speed control is 1275 needed userspace package i8kutils. 1276 1277 Say Y if you intend to run this kernel on old Dell laptops or want to 1278 use userspace package i8kutils. 1279 Say N otherwise. 1280 1281config X86_REBOOTFIXUPS 1282 bool "Enable X86 board specific fixups for reboot" 1283 depends on X86_32 1284 help 1285 This enables chipset and/or board specific fixups to be done 1286 in order to get reboot to work correctly. This is only needed on 1287 some combinations of hardware and BIOS. The symptom, for which 1288 this config is intended, is when reboot ends with a stalled/hung 1289 system. 1290 1291 Currently, the only fixup is for the Geode machines using 1292 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1293 1294 Say Y if you want to enable the fixup. Currently, it's safe to 1295 enable this option even if you don't need it. 1296 Say N otherwise. 1297 1298config MICROCODE 1299 bool "CPU microcode loading support" 1300 default y 1301 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1302 help 1303 If you say Y here, you will be able to update the microcode on 1304 Intel and AMD processors. The Intel support is for the IA32 family, 1305 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1306 AMD support is for families 0x10 and later. You will obviously need 1307 the actual microcode binary data itself which is not shipped with 1308 the Linux kernel. 1309 1310 The preferred method to load microcode from a detached initrd is described 1311 in Documentation/x86/microcode.rst. For that you need to enable 1312 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1313 initrd for microcode blobs. 1314 1315 In addition, you can build the microcode into the kernel. For that you 1316 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1317 config option. 1318 1319config MICROCODE_INTEL 1320 bool "Intel microcode loading support" 1321 depends on MICROCODE 1322 default MICROCODE 1323 help 1324 This options enables microcode patch loading support for Intel 1325 processors. 1326 1327 For the current Intel microcode data package go to 1328 <https://downloadcenter.intel.com> and search for 1329 'Linux Processor Microcode Data File'. 1330 1331config MICROCODE_AMD 1332 bool "AMD microcode loading support" 1333 depends on MICROCODE 1334 help 1335 If you select this option, microcode patch loading support for AMD 1336 processors will be enabled. 1337 1338config MICROCODE_OLD_INTERFACE 1339 bool "Ancient loading interface (DEPRECATED)" 1340 default n 1341 depends on MICROCODE 1342 help 1343 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1344 which was used by userspace tools like iucode_tool and microcode.ctl. 1345 It is inadequate because it runs too late to be able to properly 1346 load microcode on a machine and it needs special tools. Instead, you 1347 should've switched to the early loading method with the initrd or 1348 builtin microcode by now: Documentation/x86/microcode.rst 1349 1350config X86_MSR 1351 tristate "/dev/cpu/*/msr - Model-specific register support" 1352 help 1353 This device gives privileged processes access to the x86 1354 Model-Specific Registers (MSRs). It is a character device with 1355 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1356 MSR accesses are directed to a specific CPU on multi-processor 1357 systems. 1358 1359config X86_CPUID 1360 tristate "/dev/cpu/*/cpuid - CPU information support" 1361 help 1362 This device gives processes access to the x86 CPUID instruction to 1363 be executed on a specific processor. It is a character device 1364 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1365 /dev/cpu/31/cpuid. 1366 1367choice 1368 prompt "High Memory Support" 1369 default HIGHMEM4G 1370 depends on X86_32 1371 1372config NOHIGHMEM 1373 bool "off" 1374 help 1375 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1376 However, the address space of 32-bit x86 processors is only 4 1377 Gigabytes large. That means that, if you have a large amount of 1378 physical memory, not all of it can be "permanently mapped" by the 1379 kernel. The physical memory that's not permanently mapped is called 1380 "high memory". 1381 1382 If you are compiling a kernel which will never run on a machine with 1383 more than 1 Gigabyte total physical RAM, answer "off" here (default 1384 choice and suitable for most users). This will result in a "3GB/1GB" 1385 split: 3GB are mapped so that each process sees a 3GB virtual memory 1386 space and the remaining part of the 4GB virtual memory space is used 1387 by the kernel to permanently map as much physical memory as 1388 possible. 1389 1390 If the machine has between 1 and 4 Gigabytes physical RAM, then 1391 answer "4GB" here. 1392 1393 If more than 4 Gigabytes is used then answer "64GB" here. This 1394 selection turns Intel PAE (Physical Address Extension) mode on. 1395 PAE implements 3-level paging on IA32 processors. PAE is fully 1396 supported by Linux, PAE mode is implemented on all recent Intel 1397 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1398 then the kernel will not boot on CPUs that don't support PAE! 1399 1400 The actual amount of total physical memory will either be 1401 auto detected or can be forced by using a kernel command line option 1402 such as "mem=256M". (Try "man bootparam" or see the documentation of 1403 your boot loader (lilo or loadlin) about how to pass options to the 1404 kernel at boot time.) 1405 1406 If unsure, say "off". 1407 1408config HIGHMEM4G 1409 bool "4GB" 1410 help 1411 Select this if you have a 32-bit processor and between 1 and 4 1412 gigabytes of physical RAM. 1413 1414config HIGHMEM64G 1415 bool "64GB" 1416 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1417 select X86_PAE 1418 help 1419 Select this if you have a 32-bit processor and more than 4 1420 gigabytes of physical RAM. 1421 1422endchoice 1423 1424choice 1425 prompt "Memory split" if EXPERT 1426 default VMSPLIT_3G 1427 depends on X86_32 1428 help 1429 Select the desired split between kernel and user memory. 1430 1431 If the address range available to the kernel is less than the 1432 physical memory installed, the remaining memory will be available 1433 as "high memory". Accessing high memory is a little more costly 1434 than low memory, as it needs to be mapped into the kernel first. 1435 Note that increasing the kernel address space limits the range 1436 available to user programs, making the address space there 1437 tighter. Selecting anything other than the default 3G/1G split 1438 will also likely make your kernel incompatible with binary-only 1439 kernel modules. 1440 1441 If you are not absolutely sure what you are doing, leave this 1442 option alone! 1443 1444 config VMSPLIT_3G 1445 bool "3G/1G user/kernel split" 1446 config VMSPLIT_3G_OPT 1447 depends on !X86_PAE 1448 bool "3G/1G user/kernel split (for full 1G low memory)" 1449 config VMSPLIT_2G 1450 bool "2G/2G user/kernel split" 1451 config VMSPLIT_2G_OPT 1452 depends on !X86_PAE 1453 bool "2G/2G user/kernel split (for full 2G low memory)" 1454 config VMSPLIT_1G 1455 bool "1G/3G user/kernel split" 1456endchoice 1457 1458config PAGE_OFFSET 1459 hex 1460 default 0xB0000000 if VMSPLIT_3G_OPT 1461 default 0x80000000 if VMSPLIT_2G 1462 default 0x78000000 if VMSPLIT_2G_OPT 1463 default 0x40000000 if VMSPLIT_1G 1464 default 0xC0000000 1465 depends on X86_32 1466 1467config HIGHMEM 1468 def_bool y 1469 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1470 1471config X86_PAE 1472 bool "PAE (Physical Address Extension) Support" 1473 depends on X86_32 && !HIGHMEM4G 1474 select PHYS_ADDR_T_64BIT 1475 select SWIOTLB 1476 help 1477 PAE is required for NX support, and furthermore enables 1478 larger swapspace support for non-overcommit purposes. It 1479 has the cost of more pagetable lookup overhead, and also 1480 consumes more pagetable space per process. 1481 1482config X86_5LEVEL 1483 bool "Enable 5-level page tables support" 1484 default y 1485 select DYNAMIC_MEMORY_LAYOUT 1486 select SPARSEMEM_VMEMMAP 1487 depends on X86_64 1488 help 1489 5-level paging enables access to larger address space: 1490 upto 128 PiB of virtual address space and 4 PiB of 1491 physical address space. 1492 1493 It will be supported by future Intel CPUs. 1494 1495 A kernel with the option enabled can be booted on machines that 1496 support 4- or 5-level paging. 1497 1498 See Documentation/x86/x86_64/5level-paging.rst for more 1499 information. 1500 1501 Say N if unsure. 1502 1503config X86_DIRECT_GBPAGES 1504 def_bool y 1505 depends on X86_64 1506 help 1507 Certain kernel features effectively disable kernel 1508 linear 1 GB mappings (even if the CPU otherwise 1509 supports them), so don't confuse the user by printing 1510 that we have them enabled. 1511 1512config X86_CPA_STATISTICS 1513 bool "Enable statistic for Change Page Attribute" 1514 depends on DEBUG_FS 1515 help 1516 Expose statistics about the Change Page Attribute mechanism, which 1517 helps to determine the effectiveness of preserving large and huge 1518 page mappings when mapping protections are changed. 1519 1520config AMD_MEM_ENCRYPT 1521 bool "AMD Secure Memory Encryption (SME) support" 1522 depends on X86_64 && CPU_SUP_AMD 1523 select DMA_COHERENT_POOL 1524 select DYNAMIC_PHYSICAL_MASK 1525 select ARCH_USE_MEMREMAP_PROT 1526 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1527 select INSTRUCTION_DECODER 1528 help 1529 Say yes to enable support for the encryption of system memory. 1530 This requires an AMD processor that supports Secure Memory 1531 Encryption (SME). 1532 1533config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1534 bool "Activate AMD Secure Memory Encryption (SME) by default" 1535 default y 1536 depends on AMD_MEM_ENCRYPT 1537 help 1538 Say yes to have system memory encrypted by default if running on 1539 an AMD processor that supports Secure Memory Encryption (SME). 1540 1541 If set to Y, then the encryption of system memory can be 1542 deactivated with the mem_encrypt=off command line option. 1543 1544 If set to N, then the encryption of system memory can be 1545 activated with the mem_encrypt=on command line option. 1546 1547# Common NUMA Features 1548config NUMA 1549 bool "NUMA Memory Allocation and Scheduler Support" 1550 depends on SMP 1551 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1552 default y if X86_BIGSMP 1553 help 1554 Enable NUMA (Non-Uniform Memory Access) support. 1555 1556 The kernel will try to allocate memory used by a CPU on the 1557 local memory controller of the CPU and add some more 1558 NUMA awareness to the kernel. 1559 1560 For 64-bit this is recommended if the system is Intel Core i7 1561 (or later), AMD Opteron, or EM64T NUMA. 1562 1563 For 32-bit this is only needed if you boot a 32-bit 1564 kernel on a 64-bit NUMA platform. 1565 1566 Otherwise, you should say N. 1567 1568config AMD_NUMA 1569 def_bool y 1570 prompt "Old style AMD Opteron NUMA detection" 1571 depends on X86_64 && NUMA && PCI 1572 help 1573 Enable AMD NUMA node topology detection. You should say Y here if 1574 you have a multi processor AMD system. This uses an old method to 1575 read the NUMA configuration directly from the builtin Northbridge 1576 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1577 which also takes priority if both are compiled in. 1578 1579config X86_64_ACPI_NUMA 1580 def_bool y 1581 prompt "ACPI NUMA detection" 1582 depends on X86_64 && NUMA && ACPI && PCI 1583 select ACPI_NUMA 1584 help 1585 Enable ACPI SRAT based node topology detection. 1586 1587config NUMA_EMU 1588 bool "NUMA emulation" 1589 depends on NUMA 1590 help 1591 Enable NUMA emulation. A flat machine will be split 1592 into virtual nodes when booted with "numa=fake=N", where N is the 1593 number of nodes. This is only useful for debugging. 1594 1595config NODES_SHIFT 1596 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1597 range 1 10 1598 default "10" if MAXSMP 1599 default "6" if X86_64 1600 default "3" 1601 depends on NEED_MULTIPLE_NODES 1602 help 1603 Specify the maximum number of NUMA Nodes available on the target 1604 system. Increases memory reserved to accommodate various tables. 1605 1606config ARCH_FLATMEM_ENABLE 1607 def_bool y 1608 depends on X86_32 && !NUMA 1609 1610config ARCH_SPARSEMEM_ENABLE 1611 def_bool y 1612 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1613 select SPARSEMEM_STATIC if X86_32 1614 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1615 1616config ARCH_SPARSEMEM_DEFAULT 1617 def_bool X86_64 || (NUMA && X86_32) 1618 1619config ARCH_SELECT_MEMORY_MODEL 1620 def_bool y 1621 depends on ARCH_SPARSEMEM_ENABLE 1622 1623config ARCH_MEMORY_PROBE 1624 bool "Enable sysfs memory/probe interface" 1625 depends on X86_64 && MEMORY_HOTPLUG 1626 help 1627 This option enables a sysfs memory/probe interface for testing. 1628 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1629 If you are unsure how to answer this question, answer N. 1630 1631config ARCH_PROC_KCORE_TEXT 1632 def_bool y 1633 depends on X86_64 && PROC_KCORE 1634 1635config ILLEGAL_POINTER_VALUE 1636 hex 1637 default 0 if X86_32 1638 default 0xdead000000000000 if X86_64 1639 1640config X86_PMEM_LEGACY_DEVICE 1641 bool 1642 1643config X86_PMEM_LEGACY 1644 tristate "Support non-standard NVDIMMs and ADR protected memory" 1645 depends on PHYS_ADDR_T_64BIT 1646 depends on BLK_DEV 1647 select X86_PMEM_LEGACY_DEVICE 1648 select NUMA_KEEP_MEMINFO if NUMA 1649 select LIBNVDIMM 1650 help 1651 Treat memory marked using the non-standard e820 type of 12 as used 1652 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1653 The kernel will offer these regions to the 'pmem' driver so 1654 they can be used for persistent storage. 1655 1656 Say Y if unsure. 1657 1658config HIGHPTE 1659 bool "Allocate 3rd-level pagetables from highmem" 1660 depends on HIGHMEM 1661 help 1662 The VM uses one page table entry for each page of physical memory. 1663 For systems with a lot of RAM, this can be wasteful of precious 1664 low memory. Setting this option will put user-space page table 1665 entries in high memory. 1666 1667config X86_CHECK_BIOS_CORRUPTION 1668 bool "Check for low memory corruption" 1669 help 1670 Periodically check for memory corruption in low memory, which 1671 is suspected to be caused by BIOS. Even when enabled in the 1672 configuration, it is disabled at runtime. Enable it by 1673 setting "memory_corruption_check=1" on the kernel command 1674 line. By default it scans the low 64k of memory every 60 1675 seconds; see the memory_corruption_check_size and 1676 memory_corruption_check_period parameters in 1677 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1678 1679 When enabled with the default parameters, this option has 1680 almost no overhead, as it reserves a relatively small amount 1681 of memory and scans it infrequently. It both detects corruption 1682 and prevents it from affecting the running system. 1683 1684 It is, however, intended as a diagnostic tool; if repeatable 1685 BIOS-originated corruption always affects the same memory, 1686 you can use memmap= to prevent the kernel from using that 1687 memory. 1688 1689config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1690 bool "Set the default setting of memory_corruption_check" 1691 depends on X86_CHECK_BIOS_CORRUPTION 1692 default y 1693 help 1694 Set whether the default state of memory_corruption_check is 1695 on or off. 1696 1697config X86_RESERVE_LOW 1698 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1699 default 64 1700 range 4 640 1701 help 1702 Specify the amount of low memory to reserve for the BIOS. 1703 1704 The first page contains BIOS data structures that the kernel 1705 must not use, so that page must always be reserved. 1706 1707 By default we reserve the first 64K of physical RAM, as a 1708 number of BIOSes are known to corrupt that memory range 1709 during events such as suspend/resume or monitor cable 1710 insertion, so it must not be used by the kernel. 1711 1712 You can set this to 4 if you are absolutely sure that you 1713 trust the BIOS to get all its memory reservations and usages 1714 right. If you know your BIOS have problems beyond the 1715 default 64K area, you can set this to 640 to avoid using the 1716 entire low memory range. 1717 1718 If you have doubts about the BIOS (e.g. suspend/resume does 1719 not work or there's kernel crashes after certain hardware 1720 hotplug events) then you might want to enable 1721 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1722 typical corruption patterns. 1723 1724 Leave this to the default value of 64 if you are unsure. 1725 1726config MATH_EMULATION 1727 bool 1728 depends on MODIFY_LDT_SYSCALL 1729 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1730 help 1731 Linux can emulate a math coprocessor (used for floating point 1732 operations) if you don't have one. 486DX and Pentium processors have 1733 a math coprocessor built in, 486SX and 386 do not, unless you added 1734 a 487DX or 387, respectively. (The messages during boot time can 1735 give you some hints here ["man dmesg"].) Everyone needs either a 1736 coprocessor or this emulation. 1737 1738 If you don't have a math coprocessor, you need to say Y here; if you 1739 say Y here even though you have a coprocessor, the coprocessor will 1740 be used nevertheless. (This behavior can be changed with the kernel 1741 command line option "no387", which comes handy if your coprocessor 1742 is broken. Try "man bootparam" or see the documentation of your boot 1743 loader (lilo or loadlin) about how to pass options to the kernel at 1744 boot time.) This means that it is a good idea to say Y here if you 1745 intend to use this kernel on different machines. 1746 1747 More information about the internals of the Linux math coprocessor 1748 emulation can be found in <file:arch/x86/math-emu/README>. 1749 1750 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1751 kernel, it won't hurt. 1752 1753config MTRR 1754 def_bool y 1755 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1756 help 1757 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1758 the Memory Type Range Registers (MTRRs) may be used to control 1759 processor access to memory ranges. This is most useful if you have 1760 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1761 allows bus write transfers to be combined into a larger transfer 1762 before bursting over the PCI/AGP bus. This can increase performance 1763 of image write operations 2.5 times or more. Saying Y here creates a 1764 /proc/mtrr file which may be used to manipulate your processor's 1765 MTRRs. Typically the X server should use this. 1766 1767 This code has a reasonably generic interface so that similar 1768 control registers on other processors can be easily supported 1769 as well: 1770 1771 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1772 Registers (ARRs) which provide a similar functionality to MTRRs. For 1773 these, the ARRs are used to emulate the MTRRs. 1774 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1775 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1776 write-combining. All of these processors are supported by this code 1777 and it makes sense to say Y here if you have one of them. 1778 1779 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1780 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1781 can lead to all sorts of problems, so it's good to say Y here. 1782 1783 You can safely say Y even if your machine doesn't have MTRRs, you'll 1784 just add about 9 KB to your kernel. 1785 1786 See <file:Documentation/x86/mtrr.rst> for more information. 1787 1788config MTRR_SANITIZER 1789 def_bool y 1790 prompt "MTRR cleanup support" 1791 depends on MTRR 1792 help 1793 Convert MTRR layout from continuous to discrete, so X drivers can 1794 add writeback entries. 1795 1796 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1797 The largest mtrr entry size for a continuous block can be set with 1798 mtrr_chunk_size. 1799 1800 If unsure, say Y. 1801 1802config MTRR_SANITIZER_ENABLE_DEFAULT 1803 int "MTRR cleanup enable value (0-1)" 1804 range 0 1 1805 default "0" 1806 depends on MTRR_SANITIZER 1807 help 1808 Enable mtrr cleanup default value 1809 1810config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1811 int "MTRR cleanup spare reg num (0-7)" 1812 range 0 7 1813 default "1" 1814 depends on MTRR_SANITIZER 1815 help 1816 mtrr cleanup spare entries default, it can be changed via 1817 mtrr_spare_reg_nr=N on the kernel command line. 1818 1819config X86_PAT 1820 def_bool y 1821 prompt "x86 PAT support" if EXPERT 1822 depends on MTRR 1823 help 1824 Use PAT attributes to setup page level cache control. 1825 1826 PATs are the modern equivalents of MTRRs and are much more 1827 flexible than MTRRs. 1828 1829 Say N here if you see bootup problems (boot crash, boot hang, 1830 spontaneous reboots) or a non-working video driver. 1831 1832 If unsure, say Y. 1833 1834config ARCH_USES_PG_UNCACHED 1835 def_bool y 1836 depends on X86_PAT 1837 1838config ARCH_RANDOM 1839 def_bool y 1840 prompt "x86 architectural random number generator" if EXPERT 1841 help 1842 Enable the x86 architectural RDRAND instruction 1843 (Intel Bull Mountain technology) to generate random numbers. 1844 If supported, this is a high bandwidth, cryptographically 1845 secure hardware random number generator. 1846 1847config X86_SMAP 1848 def_bool y 1849 prompt "Supervisor Mode Access Prevention" if EXPERT 1850 help 1851 Supervisor Mode Access Prevention (SMAP) is a security 1852 feature in newer Intel processors. There is a small 1853 performance cost if this enabled and turned on; there is 1854 also a small increase in the kernel size if this is enabled. 1855 1856 If unsure, say Y. 1857 1858config X86_UMIP 1859 def_bool y 1860 prompt "User Mode Instruction Prevention" if EXPERT 1861 help 1862 User Mode Instruction Prevention (UMIP) is a security feature in 1863 some x86 processors. If enabled, a general protection fault is 1864 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1865 executed in user mode. These instructions unnecessarily expose 1866 information about the hardware state. 1867 1868 The vast majority of applications do not use these instructions. 1869 For the very few that do, software emulation is provided in 1870 specific cases in protected and virtual-8086 modes. Emulated 1871 results are dummy. 1872 1873config X86_INTEL_MEMORY_PROTECTION_KEYS 1874 prompt "Memory Protection Keys" 1875 def_bool y 1876 # Note: only available in 64-bit mode 1877 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1878 select ARCH_USES_HIGH_VMA_FLAGS 1879 select ARCH_HAS_PKEYS 1880 help 1881 Memory Protection Keys provides a mechanism for enforcing 1882 page-based protections, but without requiring modification of the 1883 page tables when an application changes protection domains. 1884 1885 For details, see Documentation/core-api/protection-keys.rst 1886 1887 If unsure, say y. 1888 1889choice 1890 prompt "TSX enable mode" 1891 depends on CPU_SUP_INTEL 1892 default X86_INTEL_TSX_MODE_OFF 1893 help 1894 Intel's TSX (Transactional Synchronization Extensions) feature 1895 allows to optimize locking protocols through lock elision which 1896 can lead to a noticeable performance boost. 1897 1898 On the other hand it has been shown that TSX can be exploited 1899 to form side channel attacks (e.g. TAA) and chances are there 1900 will be more of those attacks discovered in the future. 1901 1902 Therefore TSX is not enabled by default (aka tsx=off). An admin 1903 might override this decision by tsx=on the command line parameter. 1904 Even with TSX enabled, the kernel will attempt to enable the best 1905 possible TAA mitigation setting depending on the microcode available 1906 for the particular machine. 1907 1908 This option allows to set the default tsx mode between tsx=on, =off 1909 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1910 details. 1911 1912 Say off if not sure, auto if TSX is in use but it should be used on safe 1913 platforms or on if TSX is in use and the security aspect of tsx is not 1914 relevant. 1915 1916config X86_INTEL_TSX_MODE_OFF 1917 bool "off" 1918 help 1919 TSX is disabled if possible - equals to tsx=off command line parameter. 1920 1921config X86_INTEL_TSX_MODE_ON 1922 bool "on" 1923 help 1924 TSX is always enabled on TSX capable HW - equals the tsx=on command 1925 line parameter. 1926 1927config X86_INTEL_TSX_MODE_AUTO 1928 bool "auto" 1929 help 1930 TSX is enabled on TSX capable HW that is believed to be safe against 1931 side channel attacks- equals the tsx=auto command line parameter. 1932endchoice 1933 1934config X86_SGX 1935 bool "Software Guard eXtensions (SGX)" 1936 depends on X86_64 && CPU_SUP_INTEL 1937 depends on CRYPTO=y 1938 depends on CRYPTO_SHA256=y 1939 select SRCU 1940 select MMU_NOTIFIER 1941 help 1942 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1943 that can be used by applications to set aside private regions of code 1944 and data, referred to as enclaves. An enclave's private memory can 1945 only be accessed by code running within the enclave. Accesses from 1946 outside the enclave, including other enclaves, are disallowed by 1947 hardware. 1948 1949 If unsure, say N. 1950 1951config EFI 1952 bool "EFI runtime service support" 1953 depends on ACPI 1954 select UCS2_STRING 1955 select EFI_RUNTIME_WRAPPERS 1956 help 1957 This enables the kernel to use EFI runtime services that are 1958 available (such as the EFI variable services). 1959 1960 This option is only useful on systems that have EFI firmware. 1961 In addition, you should use the latest ELILO loader available 1962 at <http://elilo.sourceforge.net> in order to take advantage 1963 of EFI runtime services. However, even with this option, the 1964 resultant kernel should continue to boot on existing non-EFI 1965 platforms. 1966 1967config EFI_STUB 1968 bool "EFI stub support" 1969 depends on EFI && !X86_USE_3DNOW 1970 depends on $(cc-option,-mabi=ms) || X86_32 1971 select RELOCATABLE 1972 help 1973 This kernel feature allows a bzImage to be loaded directly 1974 by EFI firmware without the use of a bootloader. 1975 1976 See Documentation/admin-guide/efi-stub.rst for more information. 1977 1978config EFI_MIXED 1979 bool "EFI mixed-mode support" 1980 depends on EFI_STUB && X86_64 1981 help 1982 Enabling this feature allows a 64-bit kernel to be booted 1983 on a 32-bit firmware, provided that your CPU supports 64-bit 1984 mode. 1985 1986 Note that it is not possible to boot a mixed-mode enabled 1987 kernel via the EFI boot stub - a bootloader that supports 1988 the EFI handover protocol must be used. 1989 1990 If unsure, say N. 1991 1992source "kernel/Kconfig.hz" 1993 1994config KEXEC 1995 bool "kexec system call" 1996 select KEXEC_CORE 1997 help 1998 kexec is a system call that implements the ability to shutdown your 1999 current kernel, and to start another kernel. It is like a reboot 2000 but it is independent of the system firmware. And like a reboot 2001 you can start any kernel with it, not just Linux. 2002 2003 The name comes from the similarity to the exec system call. 2004 2005 It is an ongoing process to be certain the hardware in a machine 2006 is properly shutdown, so do not be surprised if this code does not 2007 initially work for you. As of this writing the exact hardware 2008 interface is strongly in flux, so no good recommendation can be 2009 made. 2010 2011config KEXEC_FILE 2012 bool "kexec file based system call" 2013 select KEXEC_CORE 2014 select BUILD_BIN2C 2015 depends on X86_64 2016 depends on CRYPTO=y 2017 depends on CRYPTO_SHA256=y 2018 help 2019 This is new version of kexec system call. This system call is 2020 file based and takes file descriptors as system call argument 2021 for kernel and initramfs as opposed to list of segments as 2022 accepted by previous system call. 2023 2024config ARCH_HAS_KEXEC_PURGATORY 2025 def_bool KEXEC_FILE 2026 2027config KEXEC_SIG 2028 bool "Verify kernel signature during kexec_file_load() syscall" 2029 depends on KEXEC_FILE 2030 help 2031 2032 This option makes the kexec_file_load() syscall check for a valid 2033 signature of the kernel image. The image can still be loaded without 2034 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2035 there's a signature that we can check, then it must be valid. 2036 2037 In addition to this option, you need to enable signature 2038 verification for the corresponding kernel image type being 2039 loaded in order for this to work. 2040 2041config KEXEC_SIG_FORCE 2042 bool "Require a valid signature in kexec_file_load() syscall" 2043 depends on KEXEC_SIG 2044 help 2045 This option makes kernel signature verification mandatory for 2046 the kexec_file_load() syscall. 2047 2048config KEXEC_BZIMAGE_VERIFY_SIG 2049 bool "Enable bzImage signature verification support" 2050 depends on KEXEC_SIG 2051 depends on SIGNED_PE_FILE_VERIFICATION 2052 select SYSTEM_TRUSTED_KEYRING 2053 help 2054 Enable bzImage signature verification support. 2055 2056config CRASH_DUMP 2057 bool "kernel crash dumps" 2058 depends on X86_64 || (X86_32 && HIGHMEM) 2059 help 2060 Generate crash dump after being started by kexec. 2061 This should be normally only set in special crash dump kernels 2062 which are loaded in the main kernel with kexec-tools into 2063 a specially reserved region and then later executed after 2064 a crash by kdump/kexec. The crash dump kernel must be compiled 2065 to a memory address not used by the main kernel or BIOS using 2066 PHYSICAL_START, or it must be built as a relocatable image 2067 (CONFIG_RELOCATABLE=y). 2068 For more details see Documentation/admin-guide/kdump/kdump.rst 2069 2070config KEXEC_JUMP 2071 bool "kexec jump" 2072 depends on KEXEC && HIBERNATION 2073 help 2074 Jump between original kernel and kexeced kernel and invoke 2075 code in physical address mode via KEXEC 2076 2077config PHYSICAL_START 2078 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2079 default "0x1000000" 2080 help 2081 This gives the physical address where the kernel is loaded. 2082 2083 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2084 bzImage will decompress itself to above physical address and 2085 run from there. Otherwise, bzImage will run from the address where 2086 it has been loaded by the boot loader and will ignore above physical 2087 address. 2088 2089 In normal kdump cases one does not have to set/change this option 2090 as now bzImage can be compiled as a completely relocatable image 2091 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2092 address. This option is mainly useful for the folks who don't want 2093 to use a bzImage for capturing the crash dump and want to use a 2094 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2095 to be specifically compiled to run from a specific memory area 2096 (normally a reserved region) and this option comes handy. 2097 2098 So if you are using bzImage for capturing the crash dump, 2099 leave the value here unchanged to 0x1000000 and set 2100 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2101 for capturing the crash dump change this value to start of 2102 the reserved region. In other words, it can be set based on 2103 the "X" value as specified in the "crashkernel=YM@XM" 2104 command line boot parameter passed to the panic-ed 2105 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2106 for more details about crash dumps. 2107 2108 Usage of bzImage for capturing the crash dump is recommended as 2109 one does not have to build two kernels. Same kernel can be used 2110 as production kernel and capture kernel. Above option should have 2111 gone away after relocatable bzImage support is introduced. But it 2112 is present because there are users out there who continue to use 2113 vmlinux for dump capture. This option should go away down the 2114 line. 2115 2116 Don't change this unless you know what you are doing. 2117 2118config RELOCATABLE 2119 bool "Build a relocatable kernel" 2120 default y 2121 help 2122 This builds a kernel image that retains relocation information 2123 so it can be loaded someplace besides the default 1MB. 2124 The relocations tend to make the kernel binary about 10% larger, 2125 but are discarded at runtime. 2126 2127 One use is for the kexec on panic case where the recovery kernel 2128 must live at a different physical address than the primary 2129 kernel. 2130 2131 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2132 it has been loaded at and the compile time physical address 2133 (CONFIG_PHYSICAL_START) is used as the minimum location. 2134 2135config RANDOMIZE_BASE 2136 bool "Randomize the address of the kernel image (KASLR)" 2137 depends on RELOCATABLE 2138 default y 2139 help 2140 In support of Kernel Address Space Layout Randomization (KASLR), 2141 this randomizes the physical address at which the kernel image 2142 is decompressed and the virtual address where the kernel 2143 image is mapped, as a security feature that deters exploit 2144 attempts relying on knowledge of the location of kernel 2145 code internals. 2146 2147 On 64-bit, the kernel physical and virtual addresses are 2148 randomized separately. The physical address will be anywhere 2149 between 16MB and the top of physical memory (up to 64TB). The 2150 virtual address will be randomized from 16MB up to 1GB (9 bits 2151 of entropy). Note that this also reduces the memory space 2152 available to kernel modules from 1.5GB to 1GB. 2153 2154 On 32-bit, the kernel physical and virtual addresses are 2155 randomized together. They will be randomized from 16MB up to 2156 512MB (8 bits of entropy). 2157 2158 Entropy is generated using the RDRAND instruction if it is 2159 supported. If RDTSC is supported, its value is mixed into 2160 the entropy pool as well. If neither RDRAND nor RDTSC are 2161 supported, then entropy is read from the i8254 timer. The 2162 usable entropy is limited by the kernel being built using 2163 2GB addressing, and that PHYSICAL_ALIGN must be at a 2164 minimum of 2MB. As a result, only 10 bits of entropy are 2165 theoretically possible, but the implementations are further 2166 limited due to memory layouts. 2167 2168 If unsure, say Y. 2169 2170# Relocation on x86 needs some additional build support 2171config X86_NEED_RELOCS 2172 def_bool y 2173 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2174 2175config PHYSICAL_ALIGN 2176 hex "Alignment value to which kernel should be aligned" 2177 default "0x200000" 2178 range 0x2000 0x1000000 if X86_32 2179 range 0x200000 0x1000000 if X86_64 2180 help 2181 This value puts the alignment restrictions on physical address 2182 where kernel is loaded and run from. Kernel is compiled for an 2183 address which meets above alignment restriction. 2184 2185 If bootloader loads the kernel at a non-aligned address and 2186 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2187 address aligned to above value and run from there. 2188 2189 If bootloader loads the kernel at a non-aligned address and 2190 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2191 load address and decompress itself to the address it has been 2192 compiled for and run from there. The address for which kernel is 2193 compiled already meets above alignment restrictions. Hence the 2194 end result is that kernel runs from a physical address meeting 2195 above alignment restrictions. 2196 2197 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2198 this value must be a multiple of 0x200000. 2199 2200 Don't change this unless you know what you are doing. 2201 2202config DYNAMIC_MEMORY_LAYOUT 2203 bool 2204 help 2205 This option makes base addresses of vmalloc and vmemmap as well as 2206 __PAGE_OFFSET movable during boot. 2207 2208config RANDOMIZE_MEMORY 2209 bool "Randomize the kernel memory sections" 2210 depends on X86_64 2211 depends on RANDOMIZE_BASE 2212 select DYNAMIC_MEMORY_LAYOUT 2213 default RANDOMIZE_BASE 2214 help 2215 Randomizes the base virtual address of kernel memory sections 2216 (physical memory mapping, vmalloc & vmemmap). This security feature 2217 makes exploits relying on predictable memory locations less reliable. 2218 2219 The order of allocations remains unchanged. Entropy is generated in 2220 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2221 configuration have in average 30,000 different possible virtual 2222 addresses for each memory section. 2223 2224 If unsure, say Y. 2225 2226config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2227 hex "Physical memory mapping padding" if EXPERT 2228 depends on RANDOMIZE_MEMORY 2229 default "0xa" if MEMORY_HOTPLUG 2230 default "0x0" 2231 range 0x1 0x40 if MEMORY_HOTPLUG 2232 range 0x0 0x40 2233 help 2234 Define the padding in terabytes added to the existing physical 2235 memory size during kernel memory randomization. It is useful 2236 for memory hotplug support but reduces the entropy available for 2237 address randomization. 2238 2239 If unsure, leave at the default value. 2240 2241config HOTPLUG_CPU 2242 def_bool y 2243 depends on SMP 2244 2245config BOOTPARAM_HOTPLUG_CPU0 2246 bool "Set default setting of cpu0_hotpluggable" 2247 depends on HOTPLUG_CPU 2248 help 2249 Set whether default state of cpu0_hotpluggable is on or off. 2250 2251 Say Y here to enable CPU0 hotplug by default. If this switch 2252 is turned on, there is no need to give cpu0_hotplug kernel 2253 parameter and the CPU0 hotplug feature is enabled by default. 2254 2255 Please note: there are two known CPU0 dependencies if you want 2256 to enable the CPU0 hotplug feature either by this switch or by 2257 cpu0_hotplug kernel parameter. 2258 2259 First, resume from hibernate or suspend always starts from CPU0. 2260 So hibernate and suspend are prevented if CPU0 is offline. 2261 2262 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2263 offline if any interrupt can not migrate out of CPU0. There may 2264 be other CPU0 dependencies. 2265 2266 Please make sure the dependencies are under your control before 2267 you enable this feature. 2268 2269 Say N if you don't want to enable CPU0 hotplug feature by default. 2270 You still can enable the CPU0 hotplug feature at boot by kernel 2271 parameter cpu0_hotplug. 2272 2273config DEBUG_HOTPLUG_CPU0 2274 def_bool n 2275 prompt "Debug CPU0 hotplug" 2276 depends on HOTPLUG_CPU 2277 help 2278 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2279 soon as possible and boots up userspace with CPU0 offlined. User 2280 can online CPU0 back after boot time. 2281 2282 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2283 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2284 compilation or giving cpu0_hotplug kernel parameter at boot. 2285 2286 If unsure, say N. 2287 2288config COMPAT_VDSO 2289 def_bool n 2290 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2291 depends on COMPAT_32 2292 help 2293 Certain buggy versions of glibc will crash if they are 2294 presented with a 32-bit vDSO that is not mapped at the address 2295 indicated in its segment table. 2296 2297 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2298 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2299 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2300 the only released version with the bug, but OpenSUSE 9 2301 contains a buggy "glibc 2.3.2". 2302 2303 The symptom of the bug is that everything crashes on startup, saying: 2304 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2305 2306 Saying Y here changes the default value of the vdso32 boot 2307 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2308 This works around the glibc bug but hurts performance. 2309 2310 If unsure, say N: if you are compiling your own kernel, you 2311 are unlikely to be using a buggy version of glibc. 2312 2313choice 2314 prompt "vsyscall table for legacy applications" 2315 depends on X86_64 2316 default LEGACY_VSYSCALL_XONLY 2317 help 2318 Legacy user code that does not know how to find the vDSO expects 2319 to be able to issue three syscalls by calling fixed addresses in 2320 kernel space. Since this location is not randomized with ASLR, 2321 it can be used to assist security vulnerability exploitation. 2322 2323 This setting can be changed at boot time via the kernel command 2324 line parameter vsyscall=[emulate|xonly|none]. 2325 2326 On a system with recent enough glibc (2.14 or newer) and no 2327 static binaries, you can say None without a performance penalty 2328 to improve security. 2329 2330 If unsure, select "Emulate execution only". 2331 2332 config LEGACY_VSYSCALL_EMULATE 2333 bool "Full emulation" 2334 help 2335 The kernel traps and emulates calls into the fixed vsyscall 2336 address mapping. This makes the mapping non-executable, but 2337 it still contains readable known contents, which could be 2338 used in certain rare security vulnerability exploits. This 2339 configuration is recommended when using legacy userspace 2340 that still uses vsyscalls along with legacy binary 2341 instrumentation tools that require code to be readable. 2342 2343 An example of this type of legacy userspace is running 2344 Pin on an old binary that still uses vsyscalls. 2345 2346 config LEGACY_VSYSCALL_XONLY 2347 bool "Emulate execution only" 2348 help 2349 The kernel traps and emulates calls into the fixed vsyscall 2350 address mapping and does not allow reads. This 2351 configuration is recommended when userspace might use the 2352 legacy vsyscall area but support for legacy binary 2353 instrumentation of legacy code is not needed. It mitigates 2354 certain uses of the vsyscall area as an ASLR-bypassing 2355 buffer. 2356 2357 config LEGACY_VSYSCALL_NONE 2358 bool "None" 2359 help 2360 There will be no vsyscall mapping at all. This will 2361 eliminate any risk of ASLR bypass due to the vsyscall 2362 fixed address mapping. Attempts to use the vsyscalls 2363 will be reported to dmesg, so that either old or 2364 malicious userspace programs can be identified. 2365 2366endchoice 2367 2368config CMDLINE_BOOL 2369 bool "Built-in kernel command line" 2370 help 2371 Allow for specifying boot arguments to the kernel at 2372 build time. On some systems (e.g. embedded ones), it is 2373 necessary or convenient to provide some or all of the 2374 kernel boot arguments with the kernel itself (that is, 2375 to not rely on the boot loader to provide them.) 2376 2377 To compile command line arguments into the kernel, 2378 set this option to 'Y', then fill in the 2379 boot arguments in CONFIG_CMDLINE. 2380 2381 Systems with fully functional boot loaders (i.e. non-embedded) 2382 should leave this option set to 'N'. 2383 2384config CMDLINE 2385 string "Built-in kernel command string" 2386 depends on CMDLINE_BOOL 2387 default "" 2388 help 2389 Enter arguments here that should be compiled into the kernel 2390 image and used at boot time. If the boot loader provides a 2391 command line at boot time, it is appended to this string to 2392 form the full kernel command line, when the system boots. 2393 2394 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2395 change this behavior. 2396 2397 In most cases, the command line (whether built-in or provided 2398 by the boot loader) should specify the device for the root 2399 file system. 2400 2401config CMDLINE_OVERRIDE 2402 bool "Built-in command line overrides boot loader arguments" 2403 depends on CMDLINE_BOOL && CMDLINE != "" 2404 help 2405 Set this option to 'Y' to have the kernel ignore the boot loader 2406 command line, and use ONLY the built-in command line. 2407 2408 This is used to work around broken boot loaders. This should 2409 be set to 'N' under normal conditions. 2410 2411config MODIFY_LDT_SYSCALL 2412 bool "Enable the LDT (local descriptor table)" if EXPERT 2413 default y 2414 help 2415 Linux can allow user programs to install a per-process x86 2416 Local Descriptor Table (LDT) using the modify_ldt(2) system 2417 call. This is required to run 16-bit or segmented code such as 2418 DOSEMU or some Wine programs. It is also used by some very old 2419 threading libraries. 2420 2421 Enabling this feature adds a small amount of overhead to 2422 context switches and increases the low-level kernel attack 2423 surface. Disabling it removes the modify_ldt(2) system call. 2424 2425 Saying 'N' here may make sense for embedded or server kernels. 2426 2427source "kernel/livepatch/Kconfig" 2428 2429endmenu 2430 2431config ARCH_HAS_ADD_PAGES 2432 def_bool y 2433 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2434 2435config ARCH_ENABLE_MEMORY_HOTPLUG 2436 def_bool y 2437 depends on X86_64 || (X86_32 && HIGHMEM) 2438 2439config ARCH_ENABLE_MEMORY_HOTREMOVE 2440 def_bool y 2441 depends on MEMORY_HOTPLUG 2442 2443config USE_PERCPU_NUMA_NODE_ID 2444 def_bool y 2445 depends on NUMA 2446 2447config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2448 def_bool y 2449 depends on X86_64 || X86_PAE 2450 2451config ARCH_ENABLE_HUGEPAGE_MIGRATION 2452 def_bool y 2453 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2454 2455config ARCH_ENABLE_THP_MIGRATION 2456 def_bool y 2457 depends on X86_64 && TRANSPARENT_HUGEPAGE 2458 2459menu "Power management and ACPI options" 2460 2461config ARCH_HIBERNATION_HEADER 2462 def_bool y 2463 depends on HIBERNATION 2464 2465source "kernel/power/Kconfig" 2466 2467source "drivers/acpi/Kconfig" 2468 2469source "drivers/sfi/Kconfig" 2470 2471config X86_APM_BOOT 2472 def_bool y 2473 depends on APM 2474 2475menuconfig APM 2476 tristate "APM (Advanced Power Management) BIOS support" 2477 depends on X86_32 && PM_SLEEP 2478 help 2479 APM is a BIOS specification for saving power using several different 2480 techniques. This is mostly useful for battery powered laptops with 2481 APM compliant BIOSes. If you say Y here, the system time will be 2482 reset after a RESUME operation, the /proc/apm device will provide 2483 battery status information, and user-space programs will receive 2484 notification of APM "events" (e.g. battery status change). 2485 2486 If you select "Y" here, you can disable actual use of the APM 2487 BIOS by passing the "apm=off" option to the kernel at boot time. 2488 2489 Note that the APM support is almost completely disabled for 2490 machines with more than one CPU. 2491 2492 In order to use APM, you will need supporting software. For location 2493 and more information, read <file:Documentation/power/apm-acpi.rst> 2494 and the Battery Powered Linux mini-HOWTO, available from 2495 <http://www.tldp.org/docs.html#howto>. 2496 2497 This driver does not spin down disk drives (see the hdparm(8) 2498 manpage ("man 8 hdparm") for that), and it doesn't turn off 2499 VESA-compliant "green" monitors. 2500 2501 This driver does not support the TI 4000M TravelMate and the ACER 2502 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2503 desktop machines also don't have compliant BIOSes, and this driver 2504 may cause those machines to panic during the boot phase. 2505 2506 Generally, if you don't have a battery in your machine, there isn't 2507 much point in using this driver and you should say N. If you get 2508 random kernel OOPSes or reboots that don't seem to be related to 2509 anything, try disabling/enabling this option (or disabling/enabling 2510 APM in your BIOS). 2511 2512 Some other things you should try when experiencing seemingly random, 2513 "weird" problems: 2514 2515 1) make sure that you have enough swap space and that it is 2516 enabled. 2517 2) pass the "no-hlt" option to the kernel 2518 3) switch on floating point emulation in the kernel and pass 2519 the "no387" option to the kernel 2520 4) pass the "floppy=nodma" option to the kernel 2521 5) pass the "mem=4M" option to the kernel (thereby disabling 2522 all but the first 4 MB of RAM) 2523 6) make sure that the CPU is not over clocked. 2524 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2525 8) disable the cache from your BIOS settings 2526 9) install a fan for the video card or exchange video RAM 2527 10) install a better fan for the CPU 2528 11) exchange RAM chips 2529 12) exchange the motherboard. 2530 2531 To compile this driver as a module, choose M here: the 2532 module will be called apm. 2533 2534if APM 2535 2536config APM_IGNORE_USER_SUSPEND 2537 bool "Ignore USER SUSPEND" 2538 help 2539 This option will ignore USER SUSPEND requests. On machines with a 2540 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2541 series notebooks, it is necessary to say Y because of a BIOS bug. 2542 2543config APM_DO_ENABLE 2544 bool "Enable PM at boot time" 2545 help 2546 Enable APM features at boot time. From page 36 of the APM BIOS 2547 specification: "When disabled, the APM BIOS does not automatically 2548 power manage devices, enter the Standby State, enter the Suspend 2549 State, or take power saving steps in response to CPU Idle calls." 2550 This driver will make CPU Idle calls when Linux is idle (unless this 2551 feature is turned off -- see "Do CPU IDLE calls", below). This 2552 should always save battery power, but more complicated APM features 2553 will be dependent on your BIOS implementation. You may need to turn 2554 this option off if your computer hangs at boot time when using APM 2555 support, or if it beeps continuously instead of suspending. Turn 2556 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2557 T400CDT. This is off by default since most machines do fine without 2558 this feature. 2559 2560config APM_CPU_IDLE 2561 depends on CPU_IDLE 2562 bool "Make CPU Idle calls when idle" 2563 help 2564 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2565 On some machines, this can activate improved power savings, such as 2566 a slowed CPU clock rate, when the machine is idle. These idle calls 2567 are made after the idle loop has run for some length of time (e.g., 2568 333 mS). On some machines, this will cause a hang at boot time or 2569 whenever the CPU becomes idle. (On machines with more than one CPU, 2570 this option does nothing.) 2571 2572config APM_DISPLAY_BLANK 2573 bool "Enable console blanking using APM" 2574 help 2575 Enable console blanking using the APM. Some laptops can use this to 2576 turn off the LCD backlight when the screen blanker of the Linux 2577 virtual console blanks the screen. Note that this is only used by 2578 the virtual console screen blanker, and won't turn off the backlight 2579 when using the X Window system. This also doesn't have anything to 2580 do with your VESA-compliant power-saving monitor. Further, this 2581 option doesn't work for all laptops -- it might not turn off your 2582 backlight at all, or it might print a lot of errors to the console, 2583 especially if you are using gpm. 2584 2585config APM_ALLOW_INTS 2586 bool "Allow interrupts during APM BIOS calls" 2587 help 2588 Normally we disable external interrupts while we are making calls to 2589 the APM BIOS as a measure to lessen the effects of a badly behaving 2590 BIOS implementation. The BIOS should reenable interrupts if it 2591 needs to. Unfortunately, some BIOSes do not -- especially those in 2592 many of the newer IBM Thinkpads. If you experience hangs when you 2593 suspend, try setting this to Y. Otherwise, say N. 2594 2595endif # APM 2596 2597source "drivers/cpufreq/Kconfig" 2598 2599source "drivers/cpuidle/Kconfig" 2600 2601source "drivers/idle/Kconfig" 2602 2603endmenu 2604 2605 2606menu "Bus options (PCI etc.)" 2607 2608choice 2609 prompt "PCI access mode" 2610 depends on X86_32 && PCI 2611 default PCI_GOANY 2612 help 2613 On PCI systems, the BIOS can be used to detect the PCI devices and 2614 determine their configuration. However, some old PCI motherboards 2615 have BIOS bugs and may crash if this is done. Also, some embedded 2616 PCI-based systems don't have any BIOS at all. Linux can also try to 2617 detect the PCI hardware directly without using the BIOS. 2618 2619 With this option, you can specify how Linux should detect the 2620 PCI devices. If you choose "BIOS", the BIOS will be used, 2621 if you choose "Direct", the BIOS won't be used, and if you 2622 choose "MMConfig", then PCI Express MMCONFIG will be used. 2623 If you choose "Any", the kernel will try MMCONFIG, then the 2624 direct access method and falls back to the BIOS if that doesn't 2625 work. If unsure, go with the default, which is "Any". 2626 2627config PCI_GOBIOS 2628 bool "BIOS" 2629 2630config PCI_GOMMCONFIG 2631 bool "MMConfig" 2632 2633config PCI_GODIRECT 2634 bool "Direct" 2635 2636config PCI_GOOLPC 2637 bool "OLPC XO-1" 2638 depends on OLPC 2639 2640config PCI_GOANY 2641 bool "Any" 2642 2643endchoice 2644 2645config PCI_BIOS 2646 def_bool y 2647 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2648 2649# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2650config PCI_DIRECT 2651 def_bool y 2652 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2653 2654config PCI_MMCONFIG 2655 bool "Support mmconfig PCI config space access" if X86_64 2656 default y 2657 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2658 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2659 2660config PCI_OLPC 2661 def_bool y 2662 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2663 2664config PCI_XEN 2665 def_bool y 2666 depends on PCI && XEN 2667 select SWIOTLB_XEN 2668 2669config MMCONF_FAM10H 2670 def_bool y 2671 depends on X86_64 && PCI_MMCONFIG && ACPI 2672 2673config PCI_CNB20LE_QUIRK 2674 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2675 depends on PCI 2676 help 2677 Read the PCI windows out of the CNB20LE host bridge. This allows 2678 PCI hotplug to work on systems with the CNB20LE chipset which do 2679 not have ACPI. 2680 2681 There's no public spec for this chipset, and this functionality 2682 is known to be incomplete. 2683 2684 You should say N unless you know you need this. 2685 2686config ISA_BUS 2687 bool "ISA bus support on modern systems" if EXPERT 2688 help 2689 Expose ISA bus device drivers and options available for selection and 2690 configuration. Enable this option if your target machine has an ISA 2691 bus. ISA is an older system, displaced by PCI and newer bus 2692 architectures -- if your target machine is modern, it probably does 2693 not have an ISA bus. 2694 2695 If unsure, say N. 2696 2697# x86_64 have no ISA slots, but can have ISA-style DMA. 2698config ISA_DMA_API 2699 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2700 default y 2701 help 2702 Enables ISA-style DMA support for devices requiring such controllers. 2703 If unsure, say Y. 2704 2705if X86_32 2706 2707config ISA 2708 bool "ISA support" 2709 help 2710 Find out whether you have ISA slots on your motherboard. ISA is the 2711 name of a bus system, i.e. the way the CPU talks to the other stuff 2712 inside your box. Other bus systems are PCI, EISA, MicroChannel 2713 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2714 newer boards don't support it. If you have ISA, say Y, otherwise N. 2715 2716config SCx200 2717 tristate "NatSemi SCx200 support" 2718 help 2719 This provides basic support for National Semiconductor's 2720 (now AMD's) Geode processors. The driver probes for the 2721 PCI-IDs of several on-chip devices, so its a good dependency 2722 for other scx200_* drivers. 2723 2724 If compiled as a module, the driver is named scx200. 2725 2726config SCx200HR_TIMER 2727 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2728 depends on SCx200 2729 default y 2730 help 2731 This driver provides a clocksource built upon the on-chip 2732 27MHz high-resolution timer. Its also a workaround for 2733 NSC Geode SC-1100's buggy TSC, which loses time when the 2734 processor goes idle (as is done by the scheduler). The 2735 other workaround is idle=poll boot option. 2736 2737config OLPC 2738 bool "One Laptop Per Child support" 2739 depends on !X86_PAE 2740 select GPIOLIB 2741 select OF 2742 select OF_PROMTREE 2743 select IRQ_DOMAIN 2744 select OLPC_EC 2745 help 2746 Add support for detecting the unique features of the OLPC 2747 XO hardware. 2748 2749config OLPC_XO1_PM 2750 bool "OLPC XO-1 Power Management" 2751 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2752 help 2753 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2754 2755config OLPC_XO1_RTC 2756 bool "OLPC XO-1 Real Time Clock" 2757 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2758 help 2759 Add support for the XO-1 real time clock, which can be used as a 2760 programmable wakeup source. 2761 2762config OLPC_XO1_SCI 2763 bool "OLPC XO-1 SCI extras" 2764 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2765 depends on INPUT=y 2766 select POWER_SUPPLY 2767 help 2768 Add support for SCI-based features of the OLPC XO-1 laptop: 2769 - EC-driven system wakeups 2770 - Power button 2771 - Ebook switch 2772 - Lid switch 2773 - AC adapter status updates 2774 - Battery status updates 2775 2776config OLPC_XO15_SCI 2777 bool "OLPC XO-1.5 SCI extras" 2778 depends on OLPC && ACPI 2779 select POWER_SUPPLY 2780 help 2781 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2782 - EC-driven system wakeups 2783 - AC adapter status updates 2784 - Battery status updates 2785 2786config ALIX 2787 bool "PCEngines ALIX System Support (LED setup)" 2788 select GPIOLIB 2789 help 2790 This option enables system support for the PCEngines ALIX. 2791 At present this just sets up LEDs for GPIO control on 2792 ALIX2/3/6 boards. However, other system specific setup should 2793 get added here. 2794 2795 Note: You must still enable the drivers for GPIO and LED support 2796 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2797 2798 Note: You have to set alix.force=1 for boards with Award BIOS. 2799 2800config NET5501 2801 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2802 select GPIOLIB 2803 help 2804 This option enables system support for the Soekris Engineering net5501. 2805 2806config GEOS 2807 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2808 select GPIOLIB 2809 depends on DMI 2810 help 2811 This option enables system support for the Traverse Technologies GEOS. 2812 2813config TS5500 2814 bool "Technologic Systems TS-5500 platform support" 2815 depends on MELAN 2816 select CHECK_SIGNATURE 2817 select NEW_LEDS 2818 select LEDS_CLASS 2819 help 2820 This option enables system support for the Technologic Systems TS-5500. 2821 2822endif # X86_32 2823 2824config AMD_NB 2825 def_bool y 2826 depends on CPU_SUP_AMD && PCI 2827 2828config X86_SYSFB 2829 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2830 help 2831 Firmwares often provide initial graphics framebuffers so the BIOS, 2832 bootloader or kernel can show basic video-output during boot for 2833 user-guidance and debugging. Historically, x86 used the VESA BIOS 2834 Extensions and EFI-framebuffers for this, which are mostly limited 2835 to x86. 2836 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2837 framebuffers so the new generic system-framebuffer drivers can be 2838 used on x86. If the framebuffer is not compatible with the generic 2839 modes, it is advertised as fallback platform framebuffer so legacy 2840 drivers like efifb, vesafb and uvesafb can pick it up. 2841 If this option is not selected, all system framebuffers are always 2842 marked as fallback platform framebuffers as usual. 2843 2844 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2845 not be able to pick up generic system framebuffers if this option 2846 is selected. You are highly encouraged to enable simplefb as 2847 replacement if you select this option. simplefb can correctly deal 2848 with generic system framebuffers. But you should still keep vesafb 2849 and others enabled as fallback if a system framebuffer is 2850 incompatible with simplefb. 2851 2852 If unsure, say Y. 2853 2854endmenu 2855 2856 2857menu "Binary Emulations" 2858 2859config IA32_EMULATION 2860 bool "IA32 Emulation" 2861 depends on X86_64 2862 select ARCH_WANT_OLD_COMPAT_IPC 2863 select BINFMT_ELF 2864 select COMPAT_OLD_SIGACTION 2865 help 2866 Include code to run legacy 32-bit programs under a 2867 64-bit kernel. You should likely turn this on, unless you're 2868 100% sure that you don't have any 32-bit programs left. 2869 2870config IA32_AOUT 2871 tristate "IA32 a.out support" 2872 depends on IA32_EMULATION 2873 depends on BROKEN 2874 help 2875 Support old a.out binaries in the 32bit emulation. 2876 2877config X86_X32 2878 bool "x32 ABI for 64-bit mode" 2879 depends on X86_64 2880 help 2881 Include code to run binaries for the x32 native 32-bit ABI 2882 for 64-bit processors. An x32 process gets access to the 2883 full 64-bit register file and wide data path while leaving 2884 pointers at 32 bits for smaller memory footprint. 2885 2886 You will need a recent binutils (2.22 or later) with 2887 elf32_x86_64 support enabled to compile a kernel with this 2888 option set. 2889 2890config COMPAT_32 2891 def_bool y 2892 depends on IA32_EMULATION || X86_32 2893 select HAVE_UID16 2894 select OLD_SIGSUSPEND3 2895 2896config COMPAT 2897 def_bool y 2898 depends on IA32_EMULATION || X86_X32 2899 2900if COMPAT 2901config COMPAT_FOR_U64_ALIGNMENT 2902 def_bool y 2903 2904config SYSVIPC_COMPAT 2905 def_bool y 2906 depends on SYSVIPC 2907endif 2908 2909endmenu 2910 2911 2912config HAVE_ATOMIC_IOMAP 2913 def_bool y 2914 depends on X86_32 2915 2916source "drivers/firmware/Kconfig" 2917 2918source "arch/x86/kvm/Kconfig" 2919 2920source "arch/x86/Kconfig.assembler" 2921