1# SPDX-License-Identifier: GPL-2.0 2# Select 32 or 64 bit 3config 64BIT 4 bool "64-bit kernel" if "$(ARCH)" = "x86" 5 default "$(ARCH)" != "i386" 6 help 7 Say yes to build a 64-bit kernel - formerly known as x86_64 8 Say no to build a 32-bit kernel - formerly known as i386 9 10config X86_32 11 def_bool y 12 depends on !64BIT 13 # Options that are inherently 32-bit kernel only: 14 select ARCH_WANT_IPC_PARSE_VERSION 15 select CLKSRC_I8253 16 select CLONE_BACKWARDS 17 select HAVE_DEBUG_STACKOVERFLOW 18 select MODULES_USE_ELF_REL 19 select OLD_SIGACTION 20 select GENERIC_VDSO_32 21 22config X86_64 23 def_bool y 24 depends on 64BIT 25 # Options that are inherently 64-bit kernel only: 26 select ARCH_HAS_GIGANTIC_PAGE 27 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 28 select ARCH_USE_CMPXCHG_LOCKREF 29 select HAVE_ARCH_SOFT_DIRTY 30 select MODULES_USE_ELF_RELA 31 select NEED_DMA_MAP_STATE 32 select SWIOTLB 33 34config FORCE_DYNAMIC_FTRACE 35 def_bool y 36 depends on X86_32 37 depends on FUNCTION_TRACER 38 select DYNAMIC_FTRACE 39 help 40 We keep the static function tracing (!DYNAMIC_FTRACE) around 41 in order to test the non static function tracing in the 42 generic code, as other architectures still use it. But we 43 only need to keep it around for x86_64. No need to keep it 44 for x86_32. For x86_32, force DYNAMIC_FTRACE. 45# 46# Arch settings 47# 48# ( Note that options that are marked 'if X86_64' could in principle be 49# ported to 32-bit as well. ) 50# 51config X86 52 def_bool y 53 # 54 # Note: keep this list sorted alphabetically 55 # 56 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 57 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 58 select ARCH_32BIT_OFF_T if X86_32 59 select ARCH_CLOCKSOURCE_INIT 60 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 61 select ARCH_HAS_DEBUG_VIRTUAL 62 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 63 select ARCH_HAS_DEVMEM_IS_ALLOWED 64 select ARCH_HAS_EARLY_DEBUG if KGDB 65 select ARCH_HAS_ELF_RANDOMIZE 66 select ARCH_HAS_FAST_MULTIPLIER 67 select ARCH_HAS_FILTER_PGPROT 68 select ARCH_HAS_FORTIFY_SOURCE 69 select ARCH_HAS_GCOV_PROFILE_ALL 70 select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION 71 select ARCH_HAS_MEM_ENCRYPT 72 select ARCH_HAS_MEMBARRIER_SYNC_CORE 73 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 74 select ARCH_HAS_PMEM_API if X86_64 75 select ARCH_HAS_PTE_DEVMAP if X86_64 76 select ARCH_HAS_PTE_SPECIAL 77 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 78 select ARCH_HAS_COPY_MC if X86_64 79 select ARCH_HAS_SET_MEMORY 80 select ARCH_HAS_SET_DIRECT_MAP 81 select ARCH_HAS_STRICT_KERNEL_RWX 82 select ARCH_HAS_STRICT_MODULE_RWX 83 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 84 select ARCH_HAS_SYSCALL_WRAPPER 85 select ARCH_HAS_UBSAN_SANITIZE_ALL 86 select ARCH_HAS_DEBUG_WX 87 select ARCH_HAVE_NMI_SAFE_CMPXCHG 88 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 89 select ARCH_MIGHT_HAVE_PC_PARPORT 90 select ARCH_MIGHT_HAVE_PC_SERIO 91 select ARCH_STACKWALK 92 select ARCH_SUPPORTS_ACPI 93 select ARCH_SUPPORTS_ATOMIC_RMW 94 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 95 select ARCH_USE_BUILTIN_BSWAP 96 select ARCH_USE_QUEUED_RWLOCKS 97 select ARCH_USE_QUEUED_SPINLOCKS 98 select ARCH_USE_SYM_ANNOTATIONS 99 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 100 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 101 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 102 select ARCH_WANT_HUGE_PMD_SHARE 103 select ARCH_WANTS_THP_SWAP if X86_64 104 select BUILDTIME_TABLE_SORT 105 select CLKEVT_I8253 106 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 107 select CLOCKSOURCE_WATCHDOG 108 select DCACHE_WORD_ACCESS 109 select EDAC_ATOMIC_SCRUB 110 select EDAC_SUPPORT 111 select GENERIC_CLOCKEVENTS 112 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 113 select GENERIC_CLOCKEVENTS_MIN_ADJUST 114 select GENERIC_CMOS_UPDATE 115 select GENERIC_CPU_AUTOPROBE 116 select GENERIC_CPU_VULNERABILITIES 117 select GENERIC_EARLY_IOREMAP 118 select GENERIC_ENTRY 119 select GENERIC_FIND_FIRST_BIT 120 select GENERIC_IOMAP 121 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 122 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 123 select GENERIC_IRQ_MIGRATION if SMP 124 select GENERIC_IRQ_PROBE 125 select GENERIC_IRQ_RESERVATION_MODE 126 select GENERIC_IRQ_SHOW 127 select GENERIC_PENDING_IRQ if SMP 128 select GENERIC_PTDUMP 129 select GENERIC_SMP_IDLE_THREAD 130 select GENERIC_STRNCPY_FROM_USER 131 select GENERIC_STRNLEN_USER 132 select GENERIC_TIME_VSYSCALL 133 select GENERIC_GETTIMEOFDAY 134 select GENERIC_VDSO_TIME_NS 135 select GUP_GET_PTE_LOW_HIGH if X86_PAE 136 select HARDIRQS_SW_RESEND 137 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 138 select HAVE_ACPI_APEI if ACPI 139 select HAVE_ACPI_APEI_NMI if ACPI 140 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 141 select HAVE_ARCH_AUDITSYSCALL 142 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 143 select HAVE_ARCH_JUMP_LABEL 144 select HAVE_ARCH_JUMP_LABEL_RELATIVE 145 select HAVE_ARCH_KASAN if X86_64 146 select HAVE_ARCH_KASAN_VMALLOC if X86_64 147 select HAVE_ARCH_KGDB 148 select HAVE_ARCH_MMAP_RND_BITS if MMU 149 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 150 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 151 select HAVE_ARCH_PREL32_RELOCATIONS 152 select HAVE_ARCH_SECCOMP_FILTER 153 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 154 select HAVE_ARCH_STACKLEAK 155 select HAVE_ARCH_TRACEHOOK 156 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 157 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 158 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 159 select HAVE_ARCH_VMAP_STACK if X86_64 160 select HAVE_ARCH_WITHIN_STACK_FRAMES 161 select HAVE_ASM_MODVERSIONS 162 select HAVE_CMPXCHG_DOUBLE 163 select HAVE_CMPXCHG_LOCAL 164 select HAVE_CONTEXT_TRACKING if X86_64 165 select HAVE_C_RECORDMCOUNT 166 select HAVE_DEBUG_KMEMLEAK 167 select HAVE_DMA_CONTIGUOUS 168 select HAVE_DYNAMIC_FTRACE 169 select HAVE_DYNAMIC_FTRACE_WITH_REGS 170 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 171 select HAVE_EBPF_JIT 172 select HAVE_EFFICIENT_UNALIGNED_ACCESS 173 select HAVE_EISA 174 select HAVE_EXIT_THREAD 175 select HAVE_FAST_GUP 176 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 177 select HAVE_FTRACE_MCOUNT_RECORD 178 select HAVE_FUNCTION_GRAPH_TRACER 179 select HAVE_FUNCTION_TRACER 180 select HAVE_GCC_PLUGINS 181 select HAVE_HW_BREAKPOINT 182 select HAVE_IDE 183 select HAVE_IOREMAP_PROT 184 select HAVE_IRQ_TIME_ACCOUNTING 185 select HAVE_KERNEL_BZIP2 186 select HAVE_KERNEL_GZIP 187 select HAVE_KERNEL_LZ4 188 select HAVE_KERNEL_LZMA 189 select HAVE_KERNEL_LZO 190 select HAVE_KERNEL_XZ 191 select HAVE_KERNEL_ZSTD 192 select HAVE_KPROBES 193 select HAVE_KPROBES_ON_FTRACE 194 select HAVE_FUNCTION_ERROR_INJECTION 195 select HAVE_KRETPROBES 196 select HAVE_KVM 197 select HAVE_LIVEPATCH if X86_64 198 select HAVE_MIXED_BREAKPOINTS_REGS 199 select HAVE_MOD_ARCH_SPECIFIC 200 select HAVE_MOVE_PMD 201 select HAVE_NMI 202 select HAVE_OPROFILE 203 select HAVE_OPTPROBES 204 select HAVE_PCSPKR_PLATFORM 205 select HAVE_PERF_EVENTS 206 select HAVE_PERF_EVENTS_NMI 207 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 208 select HAVE_PCI 209 select HAVE_PERF_REGS 210 select HAVE_PERF_USER_STACK_DUMP 211 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 212 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 213 select HAVE_REGS_AND_STACK_ACCESS_API 214 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 215 select HAVE_FUNCTION_ARG_ACCESS_API 216 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 217 select HAVE_STACK_VALIDATION if X86_64 218 select HAVE_STATIC_CALL 219 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION 220 select HAVE_RSEQ 221 select HAVE_SYSCALL_TRACEPOINTS 222 select HAVE_UNSTABLE_SCHED_CLOCK 223 select HAVE_USER_RETURN_NOTIFIER 224 select HAVE_GENERIC_VDSO 225 select HOTPLUG_SMT if SMP 226 select IRQ_FORCED_THREADING 227 select NEED_SG_DMA_LENGTH 228 select PCI_DOMAINS if PCI 229 select PCI_LOCKLESS_CONFIG if PCI 230 select PERF_EVENTS 231 select RTC_LIB 232 select RTC_MC146818_LIB 233 select SPARSE_IRQ 234 select SRCU 235 select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE) 236 select SYSCTL_EXCEPTION_TRACE 237 select THREAD_INFO_IN_TASK 238 select USER_STACKTRACE_SUPPORT 239 select VIRT_TO_BUS 240 select HAVE_ARCH_KCSAN if X86_64 241 select X86_FEATURE_NAMES if PROC_FS 242 select PROC_PID_ARCH_STATUS if PROC_FS 243 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 244 245config INSTRUCTION_DECODER 246 def_bool y 247 depends on KPROBES || PERF_EVENTS || UPROBES 248 249config OUTPUT_FORMAT 250 string 251 default "elf32-i386" if X86_32 252 default "elf64-x86-64" if X86_64 253 254config LOCKDEP_SUPPORT 255 def_bool y 256 257config STACKTRACE_SUPPORT 258 def_bool y 259 260config MMU 261 def_bool y 262 263config ARCH_MMAP_RND_BITS_MIN 264 default 28 if 64BIT 265 default 8 266 267config ARCH_MMAP_RND_BITS_MAX 268 default 32 if 64BIT 269 default 16 270 271config ARCH_MMAP_RND_COMPAT_BITS_MIN 272 default 8 273 274config ARCH_MMAP_RND_COMPAT_BITS_MAX 275 default 16 276 277config SBUS 278 bool 279 280config GENERIC_ISA_DMA 281 def_bool y 282 depends on ISA_DMA_API 283 284config GENERIC_BUG 285 def_bool y 286 depends on BUG 287 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 288 289config GENERIC_BUG_RELATIVE_POINTERS 290 bool 291 292config ARCH_MAY_HAVE_PC_FDC 293 def_bool y 294 depends on ISA_DMA_API 295 296config GENERIC_CALIBRATE_DELAY 297 def_bool y 298 299config ARCH_HAS_CPU_RELAX 300 def_bool y 301 302config ARCH_HAS_CACHE_LINE_SIZE 303 def_bool y 304 305config ARCH_HAS_FILTER_PGPROT 306 def_bool y 307 308config HAVE_SETUP_PER_CPU_AREA 309 def_bool y 310 311config NEED_PER_CPU_EMBED_FIRST_CHUNK 312 def_bool y 313 314config NEED_PER_CPU_PAGE_FIRST_CHUNK 315 def_bool y 316 317config ARCH_HIBERNATION_POSSIBLE 318 def_bool y 319 320config ARCH_SUSPEND_POSSIBLE 321 def_bool y 322 323config ARCH_WANT_GENERAL_HUGETLB 324 def_bool y 325 326config ZONE_DMA32 327 def_bool y if X86_64 328 329config AUDIT_ARCH 330 def_bool y if X86_64 331 332config ARCH_SUPPORTS_DEBUG_PAGEALLOC 333 def_bool y 334 335config KASAN_SHADOW_OFFSET 336 hex 337 depends on KASAN 338 default 0xdffffc0000000000 339 340config HAVE_INTEL_TXT 341 def_bool y 342 depends on INTEL_IOMMU && ACPI 343 344config X86_32_SMP 345 def_bool y 346 depends on X86_32 && SMP 347 348config X86_64_SMP 349 def_bool y 350 depends on X86_64 && SMP 351 352config X86_32_LAZY_GS 353 def_bool y 354 depends on X86_32 && !STACKPROTECTOR 355 356config ARCH_SUPPORTS_UPROBES 357 def_bool y 358 359config FIX_EARLYCON_MEM 360 def_bool y 361 362config DYNAMIC_PHYSICAL_MASK 363 bool 364 365config PGTABLE_LEVELS 366 int 367 default 5 if X86_5LEVEL 368 default 4 if X86_64 369 default 3 if X86_PAE 370 default 2 371 372config CC_HAS_SANE_STACKPROTECTOR 373 bool 374 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 375 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 376 help 377 We have to make sure stack protector is unconditionally disabled if 378 the compiler produces broken code. 379 380menu "Processor type and features" 381 382config ZONE_DMA 383 bool "DMA memory allocation support" if EXPERT 384 default y 385 help 386 DMA memory allocation support allows devices with less than 32-bit 387 addressing to allocate within the first 16MB of address space. 388 Disable if no such devices will be used. 389 390 If unsure, say Y. 391 392config SMP 393 bool "Symmetric multi-processing support" 394 help 395 This enables support for systems with more than one CPU. If you have 396 a system with only one CPU, say N. If you have a system with more 397 than one CPU, say Y. 398 399 If you say N here, the kernel will run on uni- and multiprocessor 400 machines, but will use only one CPU of a multiprocessor machine. If 401 you say Y here, the kernel will run on many, but not all, 402 uniprocessor machines. On a uniprocessor machine, the kernel 403 will run faster if you say N here. 404 405 Note that if you say Y here and choose architecture "586" or 406 "Pentium" under "Processor family", the kernel will not work on 486 407 architectures. Similarly, multiprocessor kernels for the "PPro" 408 architecture may not work on all Pentium based boards. 409 410 People using multiprocessor machines who say Y here should also say 411 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 412 Management" code will be disabled if you say Y here. 413 414 See also <file:Documentation/x86/i386/IO-APIC.rst>, 415 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 416 <http://www.tldp.org/docs.html#howto>. 417 418 If you don't know what to do here, say N. 419 420config X86_FEATURE_NAMES 421 bool "Processor feature human-readable names" if EMBEDDED 422 default y 423 help 424 This option compiles in a table of x86 feature bits and corresponding 425 names. This is required to support /proc/cpuinfo and a few kernel 426 messages. You can disable this to save space, at the expense of 427 making those few kernel messages show numeric feature bits instead. 428 429 If in doubt, say Y. 430 431config X86_X2APIC 432 bool "Support x2apic" 433 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 434 help 435 This enables x2apic support on CPUs that have this feature. 436 437 This allows 32-bit apic IDs (so it can support very large systems), 438 and accesses the local apic via MSRs not via mmio. 439 440 If you don't know what to do here, say N. 441 442config X86_MPPARSE 443 bool "Enable MPS table" if ACPI || SFI 444 default y 445 depends on X86_LOCAL_APIC 446 help 447 For old smp systems that do not have proper acpi support. Newer systems 448 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 449 450config GOLDFISH 451 def_bool y 452 depends on X86_GOLDFISH 453 454config RETPOLINE 455 bool "Avoid speculative indirect branches in kernel" 456 default y 457 help 458 Compile kernel with the retpoline compiler options to guard against 459 kernel-to-user data leaks by avoiding speculative indirect 460 branches. Requires a compiler with -mindirect-branch=thunk-extern 461 support for full protection. The kernel may run slower. 462 463config X86_CPU_RESCTRL 464 bool "x86 CPU resource control support" 465 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 466 select KERNFS 467 select PROC_CPU_RESCTRL if PROC_FS 468 help 469 Enable x86 CPU resource control support. 470 471 Provide support for the allocation and monitoring of system resources 472 usage by the CPU. 473 474 Intel calls this Intel Resource Director Technology 475 (Intel(R) RDT). More information about RDT can be found in the 476 Intel x86 Architecture Software Developer Manual. 477 478 AMD calls this AMD Platform Quality of Service (AMD QoS). 479 More information about AMD QoS can be found in the AMD64 Technology 480 Platform Quality of Service Extensions manual. 481 482 Say N if unsure. 483 484if X86_32 485config X86_BIGSMP 486 bool "Support for big SMP systems with more than 8 CPUs" 487 depends on SMP 488 help 489 This option is needed for the systems that have more than 8 CPUs. 490 491config X86_EXTENDED_PLATFORM 492 bool "Support for extended (non-PC) x86 platforms" 493 default y 494 help 495 If you disable this option then the kernel will only support 496 standard PC platforms. (which covers the vast majority of 497 systems out there.) 498 499 If you enable this option then you'll be able to select support 500 for the following (non-PC) 32 bit x86 platforms: 501 Goldfish (Android emulator) 502 AMD Elan 503 RDC R-321x SoC 504 SGI 320/540 (Visual Workstation) 505 STA2X11-based (e.g. Northville) 506 Moorestown MID devices 507 508 If you have one of these systems, or if you want to build a 509 generic distribution kernel, say Y here - otherwise say N. 510endif 511 512if X86_64 513config X86_EXTENDED_PLATFORM 514 bool "Support for extended (non-PC) x86 platforms" 515 default y 516 help 517 If you disable this option then the kernel will only support 518 standard PC platforms. (which covers the vast majority of 519 systems out there.) 520 521 If you enable this option then you'll be able to select support 522 for the following (non-PC) 64 bit x86 platforms: 523 Numascale NumaChip 524 ScaleMP vSMP 525 SGI Ultraviolet 526 527 If you have one of these systems, or if you want to build a 528 generic distribution kernel, say Y here - otherwise say N. 529endif 530# This is an alphabetically sorted list of 64 bit extended platforms 531# Please maintain the alphabetic order if and when there are additions 532config X86_NUMACHIP 533 bool "Numascale NumaChip" 534 depends on X86_64 535 depends on X86_EXTENDED_PLATFORM 536 depends on NUMA 537 depends on SMP 538 depends on X86_X2APIC 539 depends on PCI_MMCONFIG 540 help 541 Adds support for Numascale NumaChip large-SMP systems. Needed to 542 enable more than ~168 cores. 543 If you don't have one of these, you should say N here. 544 545config X86_VSMP 546 bool "ScaleMP vSMP" 547 select HYPERVISOR_GUEST 548 select PARAVIRT 549 depends on X86_64 && PCI 550 depends on X86_EXTENDED_PLATFORM 551 depends on SMP 552 help 553 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 554 supposed to run on these EM64T-based machines. Only choose this option 555 if you have one of these machines. 556 557config X86_UV 558 bool "SGI Ultraviolet" 559 depends on X86_64 560 depends on X86_EXTENDED_PLATFORM 561 depends on NUMA 562 depends on EFI 563 depends on X86_X2APIC 564 depends on PCI 565 help 566 This option is needed in order to support SGI Ultraviolet systems. 567 If you don't have one of these, you should say N here. 568 569# Following is an alphabetically sorted list of 32 bit extended platforms 570# Please maintain the alphabetic order if and when there are additions 571 572config X86_GOLDFISH 573 bool "Goldfish (Virtual Platform)" 574 depends on X86_EXTENDED_PLATFORM 575 help 576 Enable support for the Goldfish virtual platform used primarily 577 for Android development. Unless you are building for the Android 578 Goldfish emulator say N here. 579 580config X86_INTEL_CE 581 bool "CE4100 TV platform" 582 depends on PCI 583 depends on PCI_GODIRECT 584 depends on X86_IO_APIC 585 depends on X86_32 586 depends on X86_EXTENDED_PLATFORM 587 select X86_REBOOTFIXUPS 588 select OF 589 select OF_EARLY_FLATTREE 590 help 591 Select for the Intel CE media processor (CE4100) SOC. 592 This option compiles in support for the CE4100 SOC for settop 593 boxes and media devices. 594 595config X86_INTEL_MID 596 bool "Intel MID platform support" 597 depends on X86_EXTENDED_PLATFORM 598 depends on X86_PLATFORM_DEVICES 599 depends on PCI 600 depends on X86_64 || (PCI_GOANY && X86_32) 601 depends on X86_IO_APIC 602 select SFI 603 select I2C 604 select DW_APB_TIMER 605 select APB_TIMER 606 select INTEL_SCU_PCI 607 select MFD_INTEL_MSIC 608 help 609 Select to build a kernel capable of supporting Intel MID (Mobile 610 Internet Device) platform systems which do not have the PCI legacy 611 interfaces. If you are building for a PC class system say N here. 612 613 Intel MID platforms are based on an Intel processor and chipset which 614 consume less power than most of the x86 derivatives. 615 616config X86_INTEL_QUARK 617 bool "Intel Quark platform support" 618 depends on X86_32 619 depends on X86_EXTENDED_PLATFORM 620 depends on X86_PLATFORM_DEVICES 621 depends on X86_TSC 622 depends on PCI 623 depends on PCI_GOANY 624 depends on X86_IO_APIC 625 select IOSF_MBI 626 select INTEL_IMR 627 select COMMON_CLK 628 help 629 Select to include support for Quark X1000 SoC. 630 Say Y here if you have a Quark based system such as the Arduino 631 compatible Intel Galileo. 632 633config X86_INTEL_LPSS 634 bool "Intel Low Power Subsystem Support" 635 depends on X86 && ACPI && PCI 636 select COMMON_CLK 637 select PINCTRL 638 select IOSF_MBI 639 help 640 Select to build support for Intel Low Power Subsystem such as 641 found on Intel Lynxpoint PCH. Selecting this option enables 642 things like clock tree (common clock framework) and pincontrol 643 which are needed by the LPSS peripheral drivers. 644 645config X86_AMD_PLATFORM_DEVICE 646 bool "AMD ACPI2Platform devices support" 647 depends on ACPI 648 select COMMON_CLK 649 select PINCTRL 650 help 651 Select to interpret AMD specific ACPI device to platform device 652 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 653 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 654 implemented under PINCTRL subsystem. 655 656config IOSF_MBI 657 tristate "Intel SoC IOSF Sideband support for SoC platforms" 658 depends on PCI 659 help 660 This option enables sideband register access support for Intel SoC 661 platforms. On these platforms the IOSF sideband is used in lieu of 662 MSR's for some register accesses, mostly but not limited to thermal 663 and power. Drivers may query the availability of this device to 664 determine if they need the sideband in order to work on these 665 platforms. The sideband is available on the following SoC products. 666 This list is not meant to be exclusive. 667 - BayTrail 668 - Braswell 669 - Quark 670 671 You should say Y if you are running a kernel on one of these SoC's. 672 673config IOSF_MBI_DEBUG 674 bool "Enable IOSF sideband access through debugfs" 675 depends on IOSF_MBI && DEBUG_FS 676 help 677 Select this option to expose the IOSF sideband access registers (MCR, 678 MDR, MCRX) through debugfs to write and read register information from 679 different units on the SoC. This is most useful for obtaining device 680 state information for debug and analysis. As this is a general access 681 mechanism, users of this option would have specific knowledge of the 682 device they want to access. 683 684 If you don't require the option or are in doubt, say N. 685 686config X86_RDC321X 687 bool "RDC R-321x SoC" 688 depends on X86_32 689 depends on X86_EXTENDED_PLATFORM 690 select M486 691 select X86_REBOOTFIXUPS 692 help 693 This option is needed for RDC R-321x system-on-chip, also known 694 as R-8610-(G). 695 If you don't have one of these chips, you should say N here. 696 697config X86_32_NON_STANDARD 698 bool "Support non-standard 32-bit SMP architectures" 699 depends on X86_32 && SMP 700 depends on X86_EXTENDED_PLATFORM 701 help 702 This option compiles in the bigsmp and STA2X11 default 703 subarchitectures. It is intended for a generic binary 704 kernel. If you select them all, kernel will probe it one by 705 one and will fallback to default. 706 707# Alphabetically sorted list of Non standard 32 bit platforms 708 709config X86_SUPPORTS_MEMORY_FAILURE 710 def_bool y 711 # MCE code calls memory_failure(): 712 depends on X86_MCE 713 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 714 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 715 depends on X86_64 || !SPARSEMEM 716 select ARCH_SUPPORTS_MEMORY_FAILURE 717 718config STA2X11 719 bool "STA2X11 Companion Chip Support" 720 depends on X86_32_NON_STANDARD && PCI 721 select SWIOTLB 722 select MFD_STA2X11 723 select GPIOLIB 724 help 725 This adds support for boards based on the STA2X11 IO-Hub, 726 a.k.a. "ConneXt". The chip is used in place of the standard 727 PC chipset, so all "standard" peripherals are missing. If this 728 option is selected the kernel will still be able to boot on 729 standard PC machines. 730 731config X86_32_IRIS 732 tristate "Eurobraille/Iris poweroff module" 733 depends on X86_32 734 help 735 The Iris machines from EuroBraille do not have APM or ACPI support 736 to shut themselves down properly. A special I/O sequence is 737 needed to do so, which is what this module does at 738 kernel shutdown. 739 740 This is only for Iris machines from EuroBraille. 741 742 If unused, say N. 743 744config SCHED_OMIT_FRAME_POINTER 745 def_bool y 746 prompt "Single-depth WCHAN output" 747 depends on X86 748 help 749 Calculate simpler /proc/<PID>/wchan values. If this option 750 is disabled then wchan values will recurse back to the 751 caller function. This provides more accurate wchan values, 752 at the expense of slightly more scheduling overhead. 753 754 If in doubt, say "Y". 755 756menuconfig HYPERVISOR_GUEST 757 bool "Linux guest support" 758 help 759 Say Y here to enable options for running Linux under various hyper- 760 visors. This option enables basic hypervisor detection and platform 761 setup. 762 763 If you say N, all options in this submenu will be skipped and 764 disabled, and Linux guest support won't be built in. 765 766if HYPERVISOR_GUEST 767 768config PARAVIRT 769 bool "Enable paravirtualization code" 770 help 771 This changes the kernel so it can modify itself when it is run 772 under a hypervisor, potentially improving performance significantly 773 over full virtualization. However, when run without a hypervisor 774 the kernel is theoretically slower and slightly larger. 775 776config PARAVIRT_XXL 777 bool 778 779config PARAVIRT_DEBUG 780 bool "paravirt-ops debugging" 781 depends on PARAVIRT && DEBUG_KERNEL 782 help 783 Enable to debug paravirt_ops internals. Specifically, BUG if 784 a paravirt_op is missing when it is called. 785 786config PARAVIRT_SPINLOCKS 787 bool "Paravirtualization layer for spinlocks" 788 depends on PARAVIRT && SMP 789 help 790 Paravirtualized spinlocks allow a pvops backend to replace the 791 spinlock implementation with something virtualization-friendly 792 (for example, block the virtual CPU rather than spinning). 793 794 It has a minimal impact on native kernels and gives a nice performance 795 benefit on paravirtualized KVM / Xen kernels. 796 797 If you are unsure how to answer this question, answer Y. 798 799config X86_HV_CALLBACK_VECTOR 800 def_bool n 801 802source "arch/x86/xen/Kconfig" 803 804config KVM_GUEST 805 bool "KVM Guest support (including kvmclock)" 806 depends on PARAVIRT 807 select PARAVIRT_CLOCK 808 select ARCH_CPUIDLE_HALTPOLL 809 select X86_HV_CALLBACK_VECTOR 810 default y 811 help 812 This option enables various optimizations for running under the KVM 813 hypervisor. It includes a paravirtualized clock, so that instead 814 of relying on a PIT (or probably other) emulation by the 815 underlying device model, the host provides the guest with 816 timing infrastructure such as time of day, and system time 817 818config ARCH_CPUIDLE_HALTPOLL 819 def_bool n 820 prompt "Disable host haltpoll when loading haltpoll driver" 821 help 822 If virtualized under KVM, disable host haltpoll. 823 824config PVH 825 bool "Support for running PVH guests" 826 help 827 This option enables the PVH entry point for guest virtual machines 828 as specified in the x86/HVM direct boot ABI. 829 830config PARAVIRT_TIME_ACCOUNTING 831 bool "Paravirtual steal time accounting" 832 depends on PARAVIRT 833 help 834 Select this option to enable fine granularity task steal time 835 accounting. Time spent executing other tasks in parallel with 836 the current vCPU is discounted from the vCPU power. To account for 837 that, there can be a small performance impact. 838 839 If in doubt, say N here. 840 841config PARAVIRT_CLOCK 842 bool 843 844config JAILHOUSE_GUEST 845 bool "Jailhouse non-root cell support" 846 depends on X86_64 && PCI 847 select X86_PM_TIMER 848 help 849 This option allows to run Linux as guest in a Jailhouse non-root 850 cell. You can leave this option disabled if you only want to start 851 Jailhouse and run Linux afterwards in the root cell. 852 853config ACRN_GUEST 854 bool "ACRN Guest support" 855 depends on X86_64 856 select X86_HV_CALLBACK_VECTOR 857 help 858 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 859 a flexible, lightweight reference open-source hypervisor, built with 860 real-time and safety-criticality in mind. It is built for embedded 861 IOT with small footprint and real-time features. More details can be 862 found in https://projectacrn.org/. 863 864endif #HYPERVISOR_GUEST 865 866source "arch/x86/Kconfig.cpu" 867 868config HPET_TIMER 869 def_bool X86_64 870 prompt "HPET Timer Support" if X86_32 871 help 872 Use the IA-PC HPET (High Precision Event Timer) to manage 873 time in preference to the PIT and RTC, if a HPET is 874 present. 875 HPET is the next generation timer replacing legacy 8254s. 876 The HPET provides a stable time base on SMP 877 systems, unlike the TSC, but it is more expensive to access, 878 as it is off-chip. The interface used is documented 879 in the HPET spec, revision 1. 880 881 You can safely choose Y here. However, HPET will only be 882 activated if the platform and the BIOS support this feature. 883 Otherwise the 8254 will be used for timing services. 884 885 Choose N to continue using the legacy 8254 timer. 886 887config HPET_EMULATE_RTC 888 def_bool y 889 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 890 891config APB_TIMER 892 def_bool y if X86_INTEL_MID 893 prompt "Intel MID APB Timer Support" if X86_INTEL_MID 894 select DW_APB_TIMER 895 depends on X86_INTEL_MID && SFI 896 help 897 APB timer is the replacement for 8254, HPET on X86 MID platforms. 898 The APBT provides a stable time base on SMP 899 systems, unlike the TSC, but it is more expensive to access, 900 as it is off-chip. APB timers are always running regardless of CPU 901 C states, they are used as per CPU clockevent device when possible. 902 903# Mark as expert because too many people got it wrong. 904# The code disables itself when not needed. 905config DMI 906 default y 907 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 908 bool "Enable DMI scanning" if EXPERT 909 help 910 Enabled scanning of DMI to identify machine quirks. Say Y 911 here unless you have verified that your setup is not 912 affected by entries in the DMI blacklist. Required by PNP 913 BIOS code. 914 915config GART_IOMMU 916 bool "Old AMD GART IOMMU support" 917 select DMA_OPS 918 select IOMMU_HELPER 919 select SWIOTLB 920 depends on X86_64 && PCI && AMD_NB 921 help 922 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 923 GART based hardware IOMMUs. 924 925 The GART supports full DMA access for devices with 32-bit access 926 limitations, on systems with more than 3 GB. This is usually needed 927 for USB, sound, many IDE/SATA chipsets and some other devices. 928 929 Newer systems typically have a modern AMD IOMMU, supported via 930 the CONFIG_AMD_IOMMU=y config option. 931 932 In normal configurations this driver is only active when needed: 933 there's more than 3 GB of memory and the system contains a 934 32-bit limited device. 935 936 If unsure, say Y. 937 938config MAXSMP 939 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 940 depends on X86_64 && SMP && DEBUG_KERNEL 941 select CPUMASK_OFFSTACK 942 help 943 Enable maximum number of CPUS and NUMA Nodes for this architecture. 944 If unsure, say N. 945 946# 947# The maximum number of CPUs supported: 948# 949# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 950# and which can be configured interactively in the 951# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 952# 953# The ranges are different on 32-bit and 64-bit kernels, depending on 954# hardware capabilities and scalability features of the kernel. 955# 956# ( If MAXSMP is enabled we just use the highest possible value and disable 957# interactive configuration. ) 958# 959 960config NR_CPUS_RANGE_BEGIN 961 int 962 default NR_CPUS_RANGE_END if MAXSMP 963 default 1 if !SMP 964 default 2 965 966config NR_CPUS_RANGE_END 967 int 968 depends on X86_32 969 default 64 if SMP && X86_BIGSMP 970 default 8 if SMP && !X86_BIGSMP 971 default 1 if !SMP 972 973config NR_CPUS_RANGE_END 974 int 975 depends on X86_64 976 default 8192 if SMP && CPUMASK_OFFSTACK 977 default 512 if SMP && !CPUMASK_OFFSTACK 978 default 1 if !SMP 979 980config NR_CPUS_DEFAULT 981 int 982 depends on X86_32 983 default 32 if X86_BIGSMP 984 default 8 if SMP 985 default 1 if !SMP 986 987config NR_CPUS_DEFAULT 988 int 989 depends on X86_64 990 default 8192 if MAXSMP 991 default 64 if SMP 992 default 1 if !SMP 993 994config NR_CPUS 995 int "Maximum number of CPUs" if SMP && !MAXSMP 996 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 997 default NR_CPUS_DEFAULT 998 help 999 This allows you to specify the maximum number of CPUs which this 1000 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1001 supported value is 8192, otherwise the maximum value is 512. The 1002 minimum value which makes sense is 2. 1003 1004 This is purely to save memory: each supported CPU adds about 8KB 1005 to the kernel image. 1006 1007config SCHED_SMT 1008 def_bool y if SMP 1009 1010config SCHED_MC 1011 def_bool y 1012 prompt "Multi-core scheduler support" 1013 depends on SMP 1014 help 1015 Multi-core scheduler support improves the CPU scheduler's decision 1016 making when dealing with multi-core CPU chips at a cost of slightly 1017 increased overhead in some places. If unsure say N here. 1018 1019config SCHED_MC_PRIO 1020 bool "CPU core priorities scheduler support" 1021 depends on SCHED_MC && CPU_SUP_INTEL 1022 select X86_INTEL_PSTATE 1023 select CPU_FREQ 1024 default y 1025 help 1026 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1027 core ordering determined at manufacturing time, which allows 1028 certain cores to reach higher turbo frequencies (when running 1029 single threaded workloads) than others. 1030 1031 Enabling this kernel feature teaches the scheduler about 1032 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1033 scheduler's CPU selection logic accordingly, so that higher 1034 overall system performance can be achieved. 1035 1036 This feature will have no effect on CPUs without this feature. 1037 1038 If unsure say Y here. 1039 1040config UP_LATE_INIT 1041 def_bool y 1042 depends on !SMP && X86_LOCAL_APIC 1043 1044config X86_UP_APIC 1045 bool "Local APIC support on uniprocessors" if !PCI_MSI 1046 default PCI_MSI 1047 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1048 help 1049 A local APIC (Advanced Programmable Interrupt Controller) is an 1050 integrated interrupt controller in the CPU. If you have a single-CPU 1051 system which has a processor with a local APIC, you can say Y here to 1052 enable and use it. If you say Y here even though your machine doesn't 1053 have a local APIC, then the kernel will still run with no slowdown at 1054 all. The local APIC supports CPU-generated self-interrupts (timer, 1055 performance counters), and the NMI watchdog which detects hard 1056 lockups. 1057 1058config X86_UP_IOAPIC 1059 bool "IO-APIC support on uniprocessors" 1060 depends on X86_UP_APIC 1061 help 1062 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1063 SMP-capable replacement for PC-style interrupt controllers. Most 1064 SMP systems and many recent uniprocessor systems have one. 1065 1066 If you have a single-CPU system with an IO-APIC, you can say Y here 1067 to use it. If you say Y here even though your machine doesn't have 1068 an IO-APIC, then the kernel will still run with no slowdown at all. 1069 1070config X86_LOCAL_APIC 1071 def_bool y 1072 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1073 select IRQ_DOMAIN_HIERARCHY 1074 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1075 1076config X86_IO_APIC 1077 def_bool y 1078 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1079 1080config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1081 bool "Reroute for broken boot IRQs" 1082 depends on X86_IO_APIC 1083 help 1084 This option enables a workaround that fixes a source of 1085 spurious interrupts. This is recommended when threaded 1086 interrupt handling is used on systems where the generation of 1087 superfluous "boot interrupts" cannot be disabled. 1088 1089 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1090 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1091 kernel does during interrupt handling). On chipsets where this 1092 boot IRQ generation cannot be disabled, this workaround keeps 1093 the original IRQ line masked so that only the equivalent "boot 1094 IRQ" is delivered to the CPUs. The workaround also tells the 1095 kernel to set up the IRQ handler on the boot IRQ line. In this 1096 way only one interrupt is delivered to the kernel. Otherwise 1097 the spurious second interrupt may cause the kernel to bring 1098 down (vital) interrupt lines. 1099 1100 Only affects "broken" chipsets. Interrupt sharing may be 1101 increased on these systems. 1102 1103config X86_MCE 1104 bool "Machine Check / overheating reporting" 1105 select GENERIC_ALLOCATOR 1106 default y 1107 help 1108 Machine Check support allows the processor to notify the 1109 kernel if it detects a problem (e.g. overheating, data corruption). 1110 The action the kernel takes depends on the severity of the problem, 1111 ranging from warning messages to halting the machine. 1112 1113config X86_MCELOG_LEGACY 1114 bool "Support for deprecated /dev/mcelog character device" 1115 depends on X86_MCE 1116 help 1117 Enable support for /dev/mcelog which is needed by the old mcelog 1118 userspace logging daemon. Consider switching to the new generation 1119 rasdaemon solution. 1120 1121config X86_MCE_INTEL 1122 def_bool y 1123 prompt "Intel MCE features" 1124 depends on X86_MCE && X86_LOCAL_APIC 1125 help 1126 Additional support for intel specific MCE features such as 1127 the thermal monitor. 1128 1129config X86_MCE_AMD 1130 def_bool y 1131 prompt "AMD MCE features" 1132 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1133 help 1134 Additional support for AMD specific MCE features such as 1135 the DRAM Error Threshold. 1136 1137config X86_ANCIENT_MCE 1138 bool "Support for old Pentium 5 / WinChip machine checks" 1139 depends on X86_32 && X86_MCE 1140 help 1141 Include support for machine check handling on old Pentium 5 or WinChip 1142 systems. These typically need to be enabled explicitly on the command 1143 line. 1144 1145config X86_MCE_THRESHOLD 1146 depends on X86_MCE_AMD || X86_MCE_INTEL 1147 def_bool y 1148 1149config X86_MCE_INJECT 1150 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1151 tristate "Machine check injector support" 1152 help 1153 Provide support for injecting machine checks for testing purposes. 1154 If you don't know what a machine check is and you don't do kernel 1155 QA it is safe to say n. 1156 1157config X86_THERMAL_VECTOR 1158 def_bool y 1159 depends on X86_MCE_INTEL 1160 1161source "arch/x86/events/Kconfig" 1162 1163config X86_LEGACY_VM86 1164 bool "Legacy VM86 support" 1165 depends on X86_32 1166 help 1167 This option allows user programs to put the CPU into V8086 1168 mode, which is an 80286-era approximation of 16-bit real mode. 1169 1170 Some very old versions of X and/or vbetool require this option 1171 for user mode setting. Similarly, DOSEMU will use it if 1172 available to accelerate real mode DOS programs. However, any 1173 recent version of DOSEMU, X, or vbetool should be fully 1174 functional even without kernel VM86 support, as they will all 1175 fall back to software emulation. Nevertheless, if you are using 1176 a 16-bit DOS program where 16-bit performance matters, vm86 1177 mode might be faster than emulation and you might want to 1178 enable this option. 1179 1180 Note that any app that works on a 64-bit kernel is unlikely to 1181 need this option, as 64-bit kernels don't, and can't, support 1182 V8086 mode. This option is also unrelated to 16-bit protected 1183 mode and is not needed to run most 16-bit programs under Wine. 1184 1185 Enabling this option increases the complexity of the kernel 1186 and slows down exception handling a tiny bit. 1187 1188 If unsure, say N here. 1189 1190config VM86 1191 bool 1192 default X86_LEGACY_VM86 1193 1194config X86_16BIT 1195 bool "Enable support for 16-bit segments" if EXPERT 1196 default y 1197 depends on MODIFY_LDT_SYSCALL 1198 help 1199 This option is required by programs like Wine to run 16-bit 1200 protected mode legacy code on x86 processors. Disabling 1201 this option saves about 300 bytes on i386, or around 6K text 1202 plus 16K runtime memory on x86-64, 1203 1204config X86_ESPFIX32 1205 def_bool y 1206 depends on X86_16BIT && X86_32 1207 1208config X86_ESPFIX64 1209 def_bool y 1210 depends on X86_16BIT && X86_64 1211 1212config X86_VSYSCALL_EMULATION 1213 bool "Enable vsyscall emulation" if EXPERT 1214 default y 1215 depends on X86_64 1216 help 1217 This enables emulation of the legacy vsyscall page. Disabling 1218 it is roughly equivalent to booting with vsyscall=none, except 1219 that it will also disable the helpful warning if a program 1220 tries to use a vsyscall. With this option set to N, offending 1221 programs will just segfault, citing addresses of the form 1222 0xffffffffff600?00. 1223 1224 This option is required by many programs built before 2013, and 1225 care should be used even with newer programs if set to N. 1226 1227 Disabling this option saves about 7K of kernel size and 1228 possibly 4K of additional runtime pagetable memory. 1229 1230config X86_IOPL_IOPERM 1231 bool "IOPERM and IOPL Emulation" 1232 default y 1233 help 1234 This enables the ioperm() and iopl() syscalls which are necessary 1235 for legacy applications. 1236 1237 Legacy IOPL support is an overbroad mechanism which allows user 1238 space aside of accessing all 65536 I/O ports also to disable 1239 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1240 capabilities and permission from potentially active security 1241 modules. 1242 1243 The emulation restricts the functionality of the syscall to 1244 only allowing the full range I/O port access, but prevents the 1245 ability to disable interrupts from user space which would be 1246 granted if the hardware IOPL mechanism would be used. 1247 1248config TOSHIBA 1249 tristate "Toshiba Laptop support" 1250 depends on X86_32 1251 help 1252 This adds a driver to safely access the System Management Mode of 1253 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1254 not work on models with a Phoenix BIOS. The System Management Mode 1255 is used to set the BIOS and power saving options on Toshiba portables. 1256 1257 For information on utilities to make use of this driver see the 1258 Toshiba Linux utilities web site at: 1259 <http://www.buzzard.org.uk/toshiba/>. 1260 1261 Say Y if you intend to run this kernel on a Toshiba portable. 1262 Say N otherwise. 1263 1264config I8K 1265 tristate "Dell i8k legacy laptop support" 1266 select HWMON 1267 select SENSORS_DELL_SMM 1268 help 1269 This option enables legacy /proc/i8k userspace interface in hwmon 1270 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1271 temperature and allows controlling fan speeds of Dell laptops via 1272 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1273 it reports also power and hotkey status. For fan speed control is 1274 needed userspace package i8kutils. 1275 1276 Say Y if you intend to run this kernel on old Dell laptops or want to 1277 use userspace package i8kutils. 1278 Say N otherwise. 1279 1280config X86_REBOOTFIXUPS 1281 bool "Enable X86 board specific fixups for reboot" 1282 depends on X86_32 1283 help 1284 This enables chipset and/or board specific fixups to be done 1285 in order to get reboot to work correctly. This is only needed on 1286 some combinations of hardware and BIOS. The symptom, for which 1287 this config is intended, is when reboot ends with a stalled/hung 1288 system. 1289 1290 Currently, the only fixup is for the Geode machines using 1291 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1292 1293 Say Y if you want to enable the fixup. Currently, it's safe to 1294 enable this option even if you don't need it. 1295 Say N otherwise. 1296 1297config MICROCODE 1298 bool "CPU microcode loading support" 1299 default y 1300 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1301 help 1302 If you say Y here, you will be able to update the microcode on 1303 Intel and AMD processors. The Intel support is for the IA32 family, 1304 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1305 AMD support is for families 0x10 and later. You will obviously need 1306 the actual microcode binary data itself which is not shipped with 1307 the Linux kernel. 1308 1309 The preferred method to load microcode from a detached initrd is described 1310 in Documentation/x86/microcode.rst. For that you need to enable 1311 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1312 initrd for microcode blobs. 1313 1314 In addition, you can build the microcode into the kernel. For that you 1315 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1316 config option. 1317 1318config MICROCODE_INTEL 1319 bool "Intel microcode loading support" 1320 depends on MICROCODE 1321 default MICROCODE 1322 help 1323 This options enables microcode patch loading support for Intel 1324 processors. 1325 1326 For the current Intel microcode data package go to 1327 <https://downloadcenter.intel.com> and search for 1328 'Linux Processor Microcode Data File'. 1329 1330config MICROCODE_AMD 1331 bool "AMD microcode loading support" 1332 depends on MICROCODE 1333 help 1334 If you select this option, microcode patch loading support for AMD 1335 processors will be enabled. 1336 1337config MICROCODE_OLD_INTERFACE 1338 bool "Ancient loading interface (DEPRECATED)" 1339 default n 1340 depends on MICROCODE 1341 help 1342 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1343 which was used by userspace tools like iucode_tool and microcode.ctl. 1344 It is inadequate because it runs too late to be able to properly 1345 load microcode on a machine and it needs special tools. Instead, you 1346 should've switched to the early loading method with the initrd or 1347 builtin microcode by now: Documentation/x86/microcode.rst 1348 1349config X86_MSR 1350 tristate "/dev/cpu/*/msr - Model-specific register support" 1351 help 1352 This device gives privileged processes access to the x86 1353 Model-Specific Registers (MSRs). It is a character device with 1354 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1355 MSR accesses are directed to a specific CPU on multi-processor 1356 systems. 1357 1358config X86_CPUID 1359 tristate "/dev/cpu/*/cpuid - CPU information support" 1360 help 1361 This device gives processes access to the x86 CPUID instruction to 1362 be executed on a specific processor. It is a character device 1363 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1364 /dev/cpu/31/cpuid. 1365 1366choice 1367 prompt "High Memory Support" 1368 default HIGHMEM4G 1369 depends on X86_32 1370 1371config NOHIGHMEM 1372 bool "off" 1373 help 1374 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1375 However, the address space of 32-bit x86 processors is only 4 1376 Gigabytes large. That means that, if you have a large amount of 1377 physical memory, not all of it can be "permanently mapped" by the 1378 kernel. The physical memory that's not permanently mapped is called 1379 "high memory". 1380 1381 If you are compiling a kernel which will never run on a machine with 1382 more than 1 Gigabyte total physical RAM, answer "off" here (default 1383 choice and suitable for most users). This will result in a "3GB/1GB" 1384 split: 3GB are mapped so that each process sees a 3GB virtual memory 1385 space and the remaining part of the 4GB virtual memory space is used 1386 by the kernel to permanently map as much physical memory as 1387 possible. 1388 1389 If the machine has between 1 and 4 Gigabytes physical RAM, then 1390 answer "4GB" here. 1391 1392 If more than 4 Gigabytes is used then answer "64GB" here. This 1393 selection turns Intel PAE (Physical Address Extension) mode on. 1394 PAE implements 3-level paging on IA32 processors. PAE is fully 1395 supported by Linux, PAE mode is implemented on all recent Intel 1396 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1397 then the kernel will not boot on CPUs that don't support PAE! 1398 1399 The actual amount of total physical memory will either be 1400 auto detected or can be forced by using a kernel command line option 1401 such as "mem=256M". (Try "man bootparam" or see the documentation of 1402 your boot loader (lilo or loadlin) about how to pass options to the 1403 kernel at boot time.) 1404 1405 If unsure, say "off". 1406 1407config HIGHMEM4G 1408 bool "4GB" 1409 help 1410 Select this if you have a 32-bit processor and between 1 and 4 1411 gigabytes of physical RAM. 1412 1413config HIGHMEM64G 1414 bool "64GB" 1415 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1416 select X86_PAE 1417 help 1418 Select this if you have a 32-bit processor and more than 4 1419 gigabytes of physical RAM. 1420 1421endchoice 1422 1423choice 1424 prompt "Memory split" if EXPERT 1425 default VMSPLIT_3G 1426 depends on X86_32 1427 help 1428 Select the desired split between kernel and user memory. 1429 1430 If the address range available to the kernel is less than the 1431 physical memory installed, the remaining memory will be available 1432 as "high memory". Accessing high memory is a little more costly 1433 than low memory, as it needs to be mapped into the kernel first. 1434 Note that increasing the kernel address space limits the range 1435 available to user programs, making the address space there 1436 tighter. Selecting anything other than the default 3G/1G split 1437 will also likely make your kernel incompatible with binary-only 1438 kernel modules. 1439 1440 If you are not absolutely sure what you are doing, leave this 1441 option alone! 1442 1443 config VMSPLIT_3G 1444 bool "3G/1G user/kernel split" 1445 config VMSPLIT_3G_OPT 1446 depends on !X86_PAE 1447 bool "3G/1G user/kernel split (for full 1G low memory)" 1448 config VMSPLIT_2G 1449 bool "2G/2G user/kernel split" 1450 config VMSPLIT_2G_OPT 1451 depends on !X86_PAE 1452 bool "2G/2G user/kernel split (for full 2G low memory)" 1453 config VMSPLIT_1G 1454 bool "1G/3G user/kernel split" 1455endchoice 1456 1457config PAGE_OFFSET 1458 hex 1459 default 0xB0000000 if VMSPLIT_3G_OPT 1460 default 0x80000000 if VMSPLIT_2G 1461 default 0x78000000 if VMSPLIT_2G_OPT 1462 default 0x40000000 if VMSPLIT_1G 1463 default 0xC0000000 1464 depends on X86_32 1465 1466config HIGHMEM 1467 def_bool y 1468 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1469 1470config X86_PAE 1471 bool "PAE (Physical Address Extension) Support" 1472 depends on X86_32 && !HIGHMEM4G 1473 select PHYS_ADDR_T_64BIT 1474 select SWIOTLB 1475 help 1476 PAE is required for NX support, and furthermore enables 1477 larger swapspace support for non-overcommit purposes. It 1478 has the cost of more pagetable lookup overhead, and also 1479 consumes more pagetable space per process. 1480 1481config X86_5LEVEL 1482 bool "Enable 5-level page tables support" 1483 default y 1484 select DYNAMIC_MEMORY_LAYOUT 1485 select SPARSEMEM_VMEMMAP 1486 depends on X86_64 1487 help 1488 5-level paging enables access to larger address space: 1489 upto 128 PiB of virtual address space and 4 PiB of 1490 physical address space. 1491 1492 It will be supported by future Intel CPUs. 1493 1494 A kernel with the option enabled can be booted on machines that 1495 support 4- or 5-level paging. 1496 1497 See Documentation/x86/x86_64/5level-paging.rst for more 1498 information. 1499 1500 Say N if unsure. 1501 1502config X86_DIRECT_GBPAGES 1503 def_bool y 1504 depends on X86_64 1505 help 1506 Certain kernel features effectively disable kernel 1507 linear 1 GB mappings (even if the CPU otherwise 1508 supports them), so don't confuse the user by printing 1509 that we have them enabled. 1510 1511config X86_CPA_STATISTICS 1512 bool "Enable statistic for Change Page Attribute" 1513 depends on DEBUG_FS 1514 help 1515 Expose statistics about the Change Page Attribute mechanism, which 1516 helps to determine the effectiveness of preserving large and huge 1517 page mappings when mapping protections are changed. 1518 1519config AMD_MEM_ENCRYPT 1520 bool "AMD Secure Memory Encryption (SME) support" 1521 depends on X86_64 && CPU_SUP_AMD 1522 select DMA_COHERENT_POOL 1523 select DYNAMIC_PHYSICAL_MASK 1524 select ARCH_USE_MEMREMAP_PROT 1525 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1526 select INSTRUCTION_DECODER 1527 help 1528 Say yes to enable support for the encryption of system memory. 1529 This requires an AMD processor that supports Secure Memory 1530 Encryption (SME). 1531 1532config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1533 bool "Activate AMD Secure Memory Encryption (SME) by default" 1534 default y 1535 depends on AMD_MEM_ENCRYPT 1536 help 1537 Say yes to have system memory encrypted by default if running on 1538 an AMD processor that supports Secure Memory Encryption (SME). 1539 1540 If set to Y, then the encryption of system memory can be 1541 deactivated with the mem_encrypt=off command line option. 1542 1543 If set to N, then the encryption of system memory can be 1544 activated with the mem_encrypt=on command line option. 1545 1546# Common NUMA Features 1547config NUMA 1548 bool "NUMA Memory Allocation and Scheduler Support" 1549 depends on SMP 1550 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1551 default y if X86_BIGSMP 1552 help 1553 Enable NUMA (Non-Uniform Memory Access) support. 1554 1555 The kernel will try to allocate memory used by a CPU on the 1556 local memory controller of the CPU and add some more 1557 NUMA awareness to the kernel. 1558 1559 For 64-bit this is recommended if the system is Intel Core i7 1560 (or later), AMD Opteron, or EM64T NUMA. 1561 1562 For 32-bit this is only needed if you boot a 32-bit 1563 kernel on a 64-bit NUMA platform. 1564 1565 Otherwise, you should say N. 1566 1567config AMD_NUMA 1568 def_bool y 1569 prompt "Old style AMD Opteron NUMA detection" 1570 depends on X86_64 && NUMA && PCI 1571 help 1572 Enable AMD NUMA node topology detection. You should say Y here if 1573 you have a multi processor AMD system. This uses an old method to 1574 read the NUMA configuration directly from the builtin Northbridge 1575 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1576 which also takes priority if both are compiled in. 1577 1578config X86_64_ACPI_NUMA 1579 def_bool y 1580 prompt "ACPI NUMA detection" 1581 depends on X86_64 && NUMA && ACPI && PCI 1582 select ACPI_NUMA 1583 help 1584 Enable ACPI SRAT based node topology detection. 1585 1586config NUMA_EMU 1587 bool "NUMA emulation" 1588 depends on NUMA 1589 help 1590 Enable NUMA emulation. A flat machine will be split 1591 into virtual nodes when booted with "numa=fake=N", where N is the 1592 number of nodes. This is only useful for debugging. 1593 1594config NODES_SHIFT 1595 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1596 range 1 10 1597 default "10" if MAXSMP 1598 default "6" if X86_64 1599 default "3" 1600 depends on NEED_MULTIPLE_NODES 1601 help 1602 Specify the maximum number of NUMA Nodes available on the target 1603 system. Increases memory reserved to accommodate various tables. 1604 1605config ARCH_FLATMEM_ENABLE 1606 def_bool y 1607 depends on X86_32 && !NUMA 1608 1609config ARCH_SPARSEMEM_ENABLE 1610 def_bool y 1611 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1612 select SPARSEMEM_STATIC if X86_32 1613 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1614 1615config ARCH_SPARSEMEM_DEFAULT 1616 def_bool X86_64 || (NUMA && X86_32) 1617 1618config ARCH_SELECT_MEMORY_MODEL 1619 def_bool y 1620 depends on ARCH_SPARSEMEM_ENABLE 1621 1622config ARCH_MEMORY_PROBE 1623 bool "Enable sysfs memory/probe interface" 1624 depends on X86_64 && MEMORY_HOTPLUG 1625 help 1626 This option enables a sysfs memory/probe interface for testing. 1627 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1628 If you are unsure how to answer this question, answer N. 1629 1630config ARCH_PROC_KCORE_TEXT 1631 def_bool y 1632 depends on X86_64 && PROC_KCORE 1633 1634config ILLEGAL_POINTER_VALUE 1635 hex 1636 default 0 if X86_32 1637 default 0xdead000000000000 if X86_64 1638 1639config X86_PMEM_LEGACY_DEVICE 1640 bool 1641 1642config X86_PMEM_LEGACY 1643 tristate "Support non-standard NVDIMMs and ADR protected memory" 1644 depends on PHYS_ADDR_T_64BIT 1645 depends on BLK_DEV 1646 select X86_PMEM_LEGACY_DEVICE 1647 select NUMA_KEEP_MEMINFO if NUMA 1648 select LIBNVDIMM 1649 help 1650 Treat memory marked using the non-standard e820 type of 12 as used 1651 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1652 The kernel will offer these regions to the 'pmem' driver so 1653 they can be used for persistent storage. 1654 1655 Say Y if unsure. 1656 1657config HIGHPTE 1658 bool "Allocate 3rd-level pagetables from highmem" 1659 depends on HIGHMEM 1660 help 1661 The VM uses one page table entry for each page of physical memory. 1662 For systems with a lot of RAM, this can be wasteful of precious 1663 low memory. Setting this option will put user-space page table 1664 entries in high memory. 1665 1666config X86_CHECK_BIOS_CORRUPTION 1667 bool "Check for low memory corruption" 1668 help 1669 Periodically check for memory corruption in low memory, which 1670 is suspected to be caused by BIOS. Even when enabled in the 1671 configuration, it is disabled at runtime. Enable it by 1672 setting "memory_corruption_check=1" on the kernel command 1673 line. By default it scans the low 64k of memory every 60 1674 seconds; see the memory_corruption_check_size and 1675 memory_corruption_check_period parameters in 1676 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1677 1678 When enabled with the default parameters, this option has 1679 almost no overhead, as it reserves a relatively small amount 1680 of memory and scans it infrequently. It both detects corruption 1681 and prevents it from affecting the running system. 1682 1683 It is, however, intended as a diagnostic tool; if repeatable 1684 BIOS-originated corruption always affects the same memory, 1685 you can use memmap= to prevent the kernel from using that 1686 memory. 1687 1688config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1689 bool "Set the default setting of memory_corruption_check" 1690 depends on X86_CHECK_BIOS_CORRUPTION 1691 default y 1692 help 1693 Set whether the default state of memory_corruption_check is 1694 on or off. 1695 1696config X86_RESERVE_LOW 1697 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1698 default 64 1699 range 4 640 1700 help 1701 Specify the amount of low memory to reserve for the BIOS. 1702 1703 The first page contains BIOS data structures that the kernel 1704 must not use, so that page must always be reserved. 1705 1706 By default we reserve the first 64K of physical RAM, as a 1707 number of BIOSes are known to corrupt that memory range 1708 during events such as suspend/resume or monitor cable 1709 insertion, so it must not be used by the kernel. 1710 1711 You can set this to 4 if you are absolutely sure that you 1712 trust the BIOS to get all its memory reservations and usages 1713 right. If you know your BIOS have problems beyond the 1714 default 64K area, you can set this to 640 to avoid using the 1715 entire low memory range. 1716 1717 If you have doubts about the BIOS (e.g. suspend/resume does 1718 not work or there's kernel crashes after certain hardware 1719 hotplug events) then you might want to enable 1720 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1721 typical corruption patterns. 1722 1723 Leave this to the default value of 64 if you are unsure. 1724 1725config MATH_EMULATION 1726 bool 1727 depends on MODIFY_LDT_SYSCALL 1728 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1729 help 1730 Linux can emulate a math coprocessor (used for floating point 1731 operations) if you don't have one. 486DX and Pentium processors have 1732 a math coprocessor built in, 486SX and 386 do not, unless you added 1733 a 487DX or 387, respectively. (The messages during boot time can 1734 give you some hints here ["man dmesg"].) Everyone needs either a 1735 coprocessor or this emulation. 1736 1737 If you don't have a math coprocessor, you need to say Y here; if you 1738 say Y here even though you have a coprocessor, the coprocessor will 1739 be used nevertheless. (This behavior can be changed with the kernel 1740 command line option "no387", which comes handy if your coprocessor 1741 is broken. Try "man bootparam" or see the documentation of your boot 1742 loader (lilo or loadlin) about how to pass options to the kernel at 1743 boot time.) This means that it is a good idea to say Y here if you 1744 intend to use this kernel on different machines. 1745 1746 More information about the internals of the Linux math coprocessor 1747 emulation can be found in <file:arch/x86/math-emu/README>. 1748 1749 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1750 kernel, it won't hurt. 1751 1752config MTRR 1753 def_bool y 1754 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1755 help 1756 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1757 the Memory Type Range Registers (MTRRs) may be used to control 1758 processor access to memory ranges. This is most useful if you have 1759 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1760 allows bus write transfers to be combined into a larger transfer 1761 before bursting over the PCI/AGP bus. This can increase performance 1762 of image write operations 2.5 times or more. Saying Y here creates a 1763 /proc/mtrr file which may be used to manipulate your processor's 1764 MTRRs. Typically the X server should use this. 1765 1766 This code has a reasonably generic interface so that similar 1767 control registers on other processors can be easily supported 1768 as well: 1769 1770 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1771 Registers (ARRs) which provide a similar functionality to MTRRs. For 1772 these, the ARRs are used to emulate the MTRRs. 1773 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1774 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1775 write-combining. All of these processors are supported by this code 1776 and it makes sense to say Y here if you have one of them. 1777 1778 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1779 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1780 can lead to all sorts of problems, so it's good to say Y here. 1781 1782 You can safely say Y even if your machine doesn't have MTRRs, you'll 1783 just add about 9 KB to your kernel. 1784 1785 See <file:Documentation/x86/mtrr.rst> for more information. 1786 1787config MTRR_SANITIZER 1788 def_bool y 1789 prompt "MTRR cleanup support" 1790 depends on MTRR 1791 help 1792 Convert MTRR layout from continuous to discrete, so X drivers can 1793 add writeback entries. 1794 1795 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1796 The largest mtrr entry size for a continuous block can be set with 1797 mtrr_chunk_size. 1798 1799 If unsure, say Y. 1800 1801config MTRR_SANITIZER_ENABLE_DEFAULT 1802 int "MTRR cleanup enable value (0-1)" 1803 range 0 1 1804 default "0" 1805 depends on MTRR_SANITIZER 1806 help 1807 Enable mtrr cleanup default value 1808 1809config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1810 int "MTRR cleanup spare reg num (0-7)" 1811 range 0 7 1812 default "1" 1813 depends on MTRR_SANITIZER 1814 help 1815 mtrr cleanup spare entries default, it can be changed via 1816 mtrr_spare_reg_nr=N on the kernel command line. 1817 1818config X86_PAT 1819 def_bool y 1820 prompt "x86 PAT support" if EXPERT 1821 depends on MTRR 1822 help 1823 Use PAT attributes to setup page level cache control. 1824 1825 PATs are the modern equivalents of MTRRs and are much more 1826 flexible than MTRRs. 1827 1828 Say N here if you see bootup problems (boot crash, boot hang, 1829 spontaneous reboots) or a non-working video driver. 1830 1831 If unsure, say Y. 1832 1833config ARCH_USES_PG_UNCACHED 1834 def_bool y 1835 depends on X86_PAT 1836 1837config ARCH_RANDOM 1838 def_bool y 1839 prompt "x86 architectural random number generator" if EXPERT 1840 help 1841 Enable the x86 architectural RDRAND instruction 1842 (Intel Bull Mountain technology) to generate random numbers. 1843 If supported, this is a high bandwidth, cryptographically 1844 secure hardware random number generator. 1845 1846config X86_SMAP 1847 def_bool y 1848 prompt "Supervisor Mode Access Prevention" if EXPERT 1849 help 1850 Supervisor Mode Access Prevention (SMAP) is a security 1851 feature in newer Intel processors. There is a small 1852 performance cost if this enabled and turned on; there is 1853 also a small increase in the kernel size if this is enabled. 1854 1855 If unsure, say Y. 1856 1857config X86_UMIP 1858 def_bool y 1859 prompt "User Mode Instruction Prevention" if EXPERT 1860 help 1861 User Mode Instruction Prevention (UMIP) is a security feature in 1862 some x86 processors. If enabled, a general protection fault is 1863 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1864 executed in user mode. These instructions unnecessarily expose 1865 information about the hardware state. 1866 1867 The vast majority of applications do not use these instructions. 1868 For the very few that do, software emulation is provided in 1869 specific cases in protected and virtual-8086 modes. Emulated 1870 results are dummy. 1871 1872config X86_INTEL_MEMORY_PROTECTION_KEYS 1873 prompt "Memory Protection Keys" 1874 def_bool y 1875 # Note: only available in 64-bit mode 1876 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1877 select ARCH_USES_HIGH_VMA_FLAGS 1878 select ARCH_HAS_PKEYS 1879 help 1880 Memory Protection Keys provides a mechanism for enforcing 1881 page-based protections, but without requiring modification of the 1882 page tables when an application changes protection domains. 1883 1884 For details, see Documentation/core-api/protection-keys.rst 1885 1886 If unsure, say y. 1887 1888choice 1889 prompt "TSX enable mode" 1890 depends on CPU_SUP_INTEL 1891 default X86_INTEL_TSX_MODE_OFF 1892 help 1893 Intel's TSX (Transactional Synchronization Extensions) feature 1894 allows to optimize locking protocols through lock elision which 1895 can lead to a noticeable performance boost. 1896 1897 On the other hand it has been shown that TSX can be exploited 1898 to form side channel attacks (e.g. TAA) and chances are there 1899 will be more of those attacks discovered in the future. 1900 1901 Therefore TSX is not enabled by default (aka tsx=off). An admin 1902 might override this decision by tsx=on the command line parameter. 1903 Even with TSX enabled, the kernel will attempt to enable the best 1904 possible TAA mitigation setting depending on the microcode available 1905 for the particular machine. 1906 1907 This option allows to set the default tsx mode between tsx=on, =off 1908 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1909 details. 1910 1911 Say off if not sure, auto if TSX is in use but it should be used on safe 1912 platforms or on if TSX is in use and the security aspect of tsx is not 1913 relevant. 1914 1915config X86_INTEL_TSX_MODE_OFF 1916 bool "off" 1917 help 1918 TSX is disabled if possible - equals to tsx=off command line parameter. 1919 1920config X86_INTEL_TSX_MODE_ON 1921 bool "on" 1922 help 1923 TSX is always enabled on TSX capable HW - equals the tsx=on command 1924 line parameter. 1925 1926config X86_INTEL_TSX_MODE_AUTO 1927 bool "auto" 1928 help 1929 TSX is enabled on TSX capable HW that is believed to be safe against 1930 side channel attacks- equals the tsx=auto command line parameter. 1931endchoice 1932 1933config EFI 1934 bool "EFI runtime service support" 1935 depends on ACPI 1936 select UCS2_STRING 1937 select EFI_RUNTIME_WRAPPERS 1938 help 1939 This enables the kernel to use EFI runtime services that are 1940 available (such as the EFI variable services). 1941 1942 This option is only useful on systems that have EFI firmware. 1943 In addition, you should use the latest ELILO loader available 1944 at <http://elilo.sourceforge.net> in order to take advantage 1945 of EFI runtime services. However, even with this option, the 1946 resultant kernel should continue to boot on existing non-EFI 1947 platforms. 1948 1949config EFI_STUB 1950 bool "EFI stub support" 1951 depends on EFI && !X86_USE_3DNOW 1952 depends on $(cc-option,-mabi=ms) || X86_32 1953 select RELOCATABLE 1954 help 1955 This kernel feature allows a bzImage to be loaded directly 1956 by EFI firmware without the use of a bootloader. 1957 1958 See Documentation/admin-guide/efi-stub.rst for more information. 1959 1960config EFI_MIXED 1961 bool "EFI mixed-mode support" 1962 depends on EFI_STUB && X86_64 1963 help 1964 Enabling this feature allows a 64-bit kernel to be booted 1965 on a 32-bit firmware, provided that your CPU supports 64-bit 1966 mode. 1967 1968 Note that it is not possible to boot a mixed-mode enabled 1969 kernel via the EFI boot stub - a bootloader that supports 1970 the EFI handover protocol must be used. 1971 1972 If unsure, say N. 1973 1974source "kernel/Kconfig.hz" 1975 1976config KEXEC 1977 bool "kexec system call" 1978 select KEXEC_CORE 1979 help 1980 kexec is a system call that implements the ability to shutdown your 1981 current kernel, and to start another kernel. It is like a reboot 1982 but it is independent of the system firmware. And like a reboot 1983 you can start any kernel with it, not just Linux. 1984 1985 The name comes from the similarity to the exec system call. 1986 1987 It is an ongoing process to be certain the hardware in a machine 1988 is properly shutdown, so do not be surprised if this code does not 1989 initially work for you. As of this writing the exact hardware 1990 interface is strongly in flux, so no good recommendation can be 1991 made. 1992 1993config KEXEC_FILE 1994 bool "kexec file based system call" 1995 select KEXEC_CORE 1996 select BUILD_BIN2C 1997 depends on X86_64 1998 depends on CRYPTO=y 1999 depends on CRYPTO_SHA256=y 2000 help 2001 This is new version of kexec system call. This system call is 2002 file based and takes file descriptors as system call argument 2003 for kernel and initramfs as opposed to list of segments as 2004 accepted by previous system call. 2005 2006config ARCH_HAS_KEXEC_PURGATORY 2007 def_bool KEXEC_FILE 2008 2009config KEXEC_SIG 2010 bool "Verify kernel signature during kexec_file_load() syscall" 2011 depends on KEXEC_FILE 2012 help 2013 2014 This option makes the kexec_file_load() syscall check for a valid 2015 signature of the kernel image. The image can still be loaded without 2016 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2017 there's a signature that we can check, then it must be valid. 2018 2019 In addition to this option, you need to enable signature 2020 verification for the corresponding kernel image type being 2021 loaded in order for this to work. 2022 2023config KEXEC_SIG_FORCE 2024 bool "Require a valid signature in kexec_file_load() syscall" 2025 depends on KEXEC_SIG 2026 help 2027 This option makes kernel signature verification mandatory for 2028 the kexec_file_load() syscall. 2029 2030config KEXEC_BZIMAGE_VERIFY_SIG 2031 bool "Enable bzImage signature verification support" 2032 depends on KEXEC_SIG 2033 depends on SIGNED_PE_FILE_VERIFICATION 2034 select SYSTEM_TRUSTED_KEYRING 2035 help 2036 Enable bzImage signature verification support. 2037 2038config CRASH_DUMP 2039 bool "kernel crash dumps" 2040 depends on X86_64 || (X86_32 && HIGHMEM) 2041 help 2042 Generate crash dump after being started by kexec. 2043 This should be normally only set in special crash dump kernels 2044 which are loaded in the main kernel with kexec-tools into 2045 a specially reserved region and then later executed after 2046 a crash by kdump/kexec. The crash dump kernel must be compiled 2047 to a memory address not used by the main kernel or BIOS using 2048 PHYSICAL_START, or it must be built as a relocatable image 2049 (CONFIG_RELOCATABLE=y). 2050 For more details see Documentation/admin-guide/kdump/kdump.rst 2051 2052config KEXEC_JUMP 2053 bool "kexec jump" 2054 depends on KEXEC && HIBERNATION 2055 help 2056 Jump between original kernel and kexeced kernel and invoke 2057 code in physical address mode via KEXEC 2058 2059config PHYSICAL_START 2060 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2061 default "0x1000000" 2062 help 2063 This gives the physical address where the kernel is loaded. 2064 2065 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2066 bzImage will decompress itself to above physical address and 2067 run from there. Otherwise, bzImage will run from the address where 2068 it has been loaded by the boot loader and will ignore above physical 2069 address. 2070 2071 In normal kdump cases one does not have to set/change this option 2072 as now bzImage can be compiled as a completely relocatable image 2073 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2074 address. This option is mainly useful for the folks who don't want 2075 to use a bzImage for capturing the crash dump and want to use a 2076 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2077 to be specifically compiled to run from a specific memory area 2078 (normally a reserved region) and this option comes handy. 2079 2080 So if you are using bzImage for capturing the crash dump, 2081 leave the value here unchanged to 0x1000000 and set 2082 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2083 for capturing the crash dump change this value to start of 2084 the reserved region. In other words, it can be set based on 2085 the "X" value as specified in the "crashkernel=YM@XM" 2086 command line boot parameter passed to the panic-ed 2087 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2088 for more details about crash dumps. 2089 2090 Usage of bzImage for capturing the crash dump is recommended as 2091 one does not have to build two kernels. Same kernel can be used 2092 as production kernel and capture kernel. Above option should have 2093 gone away after relocatable bzImage support is introduced. But it 2094 is present because there are users out there who continue to use 2095 vmlinux for dump capture. This option should go away down the 2096 line. 2097 2098 Don't change this unless you know what you are doing. 2099 2100config RELOCATABLE 2101 bool "Build a relocatable kernel" 2102 default y 2103 help 2104 This builds a kernel image that retains relocation information 2105 so it can be loaded someplace besides the default 1MB. 2106 The relocations tend to make the kernel binary about 10% larger, 2107 but are discarded at runtime. 2108 2109 One use is for the kexec on panic case where the recovery kernel 2110 must live at a different physical address than the primary 2111 kernel. 2112 2113 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2114 it has been loaded at and the compile time physical address 2115 (CONFIG_PHYSICAL_START) is used as the minimum location. 2116 2117config RANDOMIZE_BASE 2118 bool "Randomize the address of the kernel image (KASLR)" 2119 depends on RELOCATABLE 2120 default y 2121 help 2122 In support of Kernel Address Space Layout Randomization (KASLR), 2123 this randomizes the physical address at which the kernel image 2124 is decompressed and the virtual address where the kernel 2125 image is mapped, as a security feature that deters exploit 2126 attempts relying on knowledge of the location of kernel 2127 code internals. 2128 2129 On 64-bit, the kernel physical and virtual addresses are 2130 randomized separately. The physical address will be anywhere 2131 between 16MB and the top of physical memory (up to 64TB). The 2132 virtual address will be randomized from 16MB up to 1GB (9 bits 2133 of entropy). Note that this also reduces the memory space 2134 available to kernel modules from 1.5GB to 1GB. 2135 2136 On 32-bit, the kernel physical and virtual addresses are 2137 randomized together. They will be randomized from 16MB up to 2138 512MB (8 bits of entropy). 2139 2140 Entropy is generated using the RDRAND instruction if it is 2141 supported. If RDTSC is supported, its value is mixed into 2142 the entropy pool as well. If neither RDRAND nor RDTSC are 2143 supported, then entropy is read from the i8254 timer. The 2144 usable entropy is limited by the kernel being built using 2145 2GB addressing, and that PHYSICAL_ALIGN must be at a 2146 minimum of 2MB. As a result, only 10 bits of entropy are 2147 theoretically possible, but the implementations are further 2148 limited due to memory layouts. 2149 2150 If unsure, say Y. 2151 2152# Relocation on x86 needs some additional build support 2153config X86_NEED_RELOCS 2154 def_bool y 2155 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2156 2157config PHYSICAL_ALIGN 2158 hex "Alignment value to which kernel should be aligned" 2159 default "0x200000" 2160 range 0x2000 0x1000000 if X86_32 2161 range 0x200000 0x1000000 if X86_64 2162 help 2163 This value puts the alignment restrictions on physical address 2164 where kernel is loaded and run from. Kernel is compiled for an 2165 address which meets above alignment restriction. 2166 2167 If bootloader loads the kernel at a non-aligned address and 2168 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2169 address aligned to above value and run from there. 2170 2171 If bootloader loads the kernel at a non-aligned address and 2172 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2173 load address and decompress itself to the address it has been 2174 compiled for and run from there. The address for which kernel is 2175 compiled already meets above alignment restrictions. Hence the 2176 end result is that kernel runs from a physical address meeting 2177 above alignment restrictions. 2178 2179 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2180 this value must be a multiple of 0x200000. 2181 2182 Don't change this unless you know what you are doing. 2183 2184config DYNAMIC_MEMORY_LAYOUT 2185 bool 2186 help 2187 This option makes base addresses of vmalloc and vmemmap as well as 2188 __PAGE_OFFSET movable during boot. 2189 2190config RANDOMIZE_MEMORY 2191 bool "Randomize the kernel memory sections" 2192 depends on X86_64 2193 depends on RANDOMIZE_BASE 2194 select DYNAMIC_MEMORY_LAYOUT 2195 default RANDOMIZE_BASE 2196 help 2197 Randomizes the base virtual address of kernel memory sections 2198 (physical memory mapping, vmalloc & vmemmap). This security feature 2199 makes exploits relying on predictable memory locations less reliable. 2200 2201 The order of allocations remains unchanged. Entropy is generated in 2202 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2203 configuration have in average 30,000 different possible virtual 2204 addresses for each memory section. 2205 2206 If unsure, say Y. 2207 2208config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2209 hex "Physical memory mapping padding" if EXPERT 2210 depends on RANDOMIZE_MEMORY 2211 default "0xa" if MEMORY_HOTPLUG 2212 default "0x0" 2213 range 0x1 0x40 if MEMORY_HOTPLUG 2214 range 0x0 0x40 2215 help 2216 Define the padding in terabytes added to the existing physical 2217 memory size during kernel memory randomization. It is useful 2218 for memory hotplug support but reduces the entropy available for 2219 address randomization. 2220 2221 If unsure, leave at the default value. 2222 2223config HOTPLUG_CPU 2224 def_bool y 2225 depends on SMP 2226 2227config BOOTPARAM_HOTPLUG_CPU0 2228 bool "Set default setting of cpu0_hotpluggable" 2229 depends on HOTPLUG_CPU 2230 help 2231 Set whether default state of cpu0_hotpluggable is on or off. 2232 2233 Say Y here to enable CPU0 hotplug by default. If this switch 2234 is turned on, there is no need to give cpu0_hotplug kernel 2235 parameter and the CPU0 hotplug feature is enabled by default. 2236 2237 Please note: there are two known CPU0 dependencies if you want 2238 to enable the CPU0 hotplug feature either by this switch or by 2239 cpu0_hotplug kernel parameter. 2240 2241 First, resume from hibernate or suspend always starts from CPU0. 2242 So hibernate and suspend are prevented if CPU0 is offline. 2243 2244 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2245 offline if any interrupt can not migrate out of CPU0. There may 2246 be other CPU0 dependencies. 2247 2248 Please make sure the dependencies are under your control before 2249 you enable this feature. 2250 2251 Say N if you don't want to enable CPU0 hotplug feature by default. 2252 You still can enable the CPU0 hotplug feature at boot by kernel 2253 parameter cpu0_hotplug. 2254 2255config DEBUG_HOTPLUG_CPU0 2256 def_bool n 2257 prompt "Debug CPU0 hotplug" 2258 depends on HOTPLUG_CPU 2259 help 2260 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2261 soon as possible and boots up userspace with CPU0 offlined. User 2262 can online CPU0 back after boot time. 2263 2264 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2265 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2266 compilation or giving cpu0_hotplug kernel parameter at boot. 2267 2268 If unsure, say N. 2269 2270config COMPAT_VDSO 2271 def_bool n 2272 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2273 depends on COMPAT_32 2274 help 2275 Certain buggy versions of glibc will crash if they are 2276 presented with a 32-bit vDSO that is not mapped at the address 2277 indicated in its segment table. 2278 2279 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2280 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2281 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2282 the only released version with the bug, but OpenSUSE 9 2283 contains a buggy "glibc 2.3.2". 2284 2285 The symptom of the bug is that everything crashes on startup, saying: 2286 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2287 2288 Saying Y here changes the default value of the vdso32 boot 2289 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2290 This works around the glibc bug but hurts performance. 2291 2292 If unsure, say N: if you are compiling your own kernel, you 2293 are unlikely to be using a buggy version of glibc. 2294 2295choice 2296 prompt "vsyscall table for legacy applications" 2297 depends on X86_64 2298 default LEGACY_VSYSCALL_XONLY 2299 help 2300 Legacy user code that does not know how to find the vDSO expects 2301 to be able to issue three syscalls by calling fixed addresses in 2302 kernel space. Since this location is not randomized with ASLR, 2303 it can be used to assist security vulnerability exploitation. 2304 2305 This setting can be changed at boot time via the kernel command 2306 line parameter vsyscall=[emulate|xonly|none]. 2307 2308 On a system with recent enough glibc (2.14 or newer) and no 2309 static binaries, you can say None without a performance penalty 2310 to improve security. 2311 2312 If unsure, select "Emulate execution only". 2313 2314 config LEGACY_VSYSCALL_EMULATE 2315 bool "Full emulation" 2316 help 2317 The kernel traps and emulates calls into the fixed vsyscall 2318 address mapping. This makes the mapping non-executable, but 2319 it still contains readable known contents, which could be 2320 used in certain rare security vulnerability exploits. This 2321 configuration is recommended when using legacy userspace 2322 that still uses vsyscalls along with legacy binary 2323 instrumentation tools that require code to be readable. 2324 2325 An example of this type of legacy userspace is running 2326 Pin on an old binary that still uses vsyscalls. 2327 2328 config LEGACY_VSYSCALL_XONLY 2329 bool "Emulate execution only" 2330 help 2331 The kernel traps and emulates calls into the fixed vsyscall 2332 address mapping and does not allow reads. This 2333 configuration is recommended when userspace might use the 2334 legacy vsyscall area but support for legacy binary 2335 instrumentation of legacy code is not needed. It mitigates 2336 certain uses of the vsyscall area as an ASLR-bypassing 2337 buffer. 2338 2339 config LEGACY_VSYSCALL_NONE 2340 bool "None" 2341 help 2342 There will be no vsyscall mapping at all. This will 2343 eliminate any risk of ASLR bypass due to the vsyscall 2344 fixed address mapping. Attempts to use the vsyscalls 2345 will be reported to dmesg, so that either old or 2346 malicious userspace programs can be identified. 2347 2348endchoice 2349 2350config CMDLINE_BOOL 2351 bool "Built-in kernel command line" 2352 help 2353 Allow for specifying boot arguments to the kernel at 2354 build time. On some systems (e.g. embedded ones), it is 2355 necessary or convenient to provide some or all of the 2356 kernel boot arguments with the kernel itself (that is, 2357 to not rely on the boot loader to provide them.) 2358 2359 To compile command line arguments into the kernel, 2360 set this option to 'Y', then fill in the 2361 boot arguments in CONFIG_CMDLINE. 2362 2363 Systems with fully functional boot loaders (i.e. non-embedded) 2364 should leave this option set to 'N'. 2365 2366config CMDLINE 2367 string "Built-in kernel command string" 2368 depends on CMDLINE_BOOL 2369 default "" 2370 help 2371 Enter arguments here that should be compiled into the kernel 2372 image and used at boot time. If the boot loader provides a 2373 command line at boot time, it is appended to this string to 2374 form the full kernel command line, when the system boots. 2375 2376 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2377 change this behavior. 2378 2379 In most cases, the command line (whether built-in or provided 2380 by the boot loader) should specify the device for the root 2381 file system. 2382 2383config CMDLINE_OVERRIDE 2384 bool "Built-in command line overrides boot loader arguments" 2385 depends on CMDLINE_BOOL && CMDLINE != "" 2386 help 2387 Set this option to 'Y' to have the kernel ignore the boot loader 2388 command line, and use ONLY the built-in command line. 2389 2390 This is used to work around broken boot loaders. This should 2391 be set to 'N' under normal conditions. 2392 2393config MODIFY_LDT_SYSCALL 2394 bool "Enable the LDT (local descriptor table)" if EXPERT 2395 default y 2396 help 2397 Linux can allow user programs to install a per-process x86 2398 Local Descriptor Table (LDT) using the modify_ldt(2) system 2399 call. This is required to run 16-bit or segmented code such as 2400 DOSEMU or some Wine programs. It is also used by some very old 2401 threading libraries. 2402 2403 Enabling this feature adds a small amount of overhead to 2404 context switches and increases the low-level kernel attack 2405 surface. Disabling it removes the modify_ldt(2) system call. 2406 2407 Saying 'N' here may make sense for embedded or server kernels. 2408 2409source "kernel/livepatch/Kconfig" 2410 2411endmenu 2412 2413config ARCH_HAS_ADD_PAGES 2414 def_bool y 2415 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2416 2417config ARCH_ENABLE_MEMORY_HOTPLUG 2418 def_bool y 2419 depends on X86_64 || (X86_32 && HIGHMEM) 2420 2421config ARCH_ENABLE_MEMORY_HOTREMOVE 2422 def_bool y 2423 depends on MEMORY_HOTPLUG 2424 2425config USE_PERCPU_NUMA_NODE_ID 2426 def_bool y 2427 depends on NUMA 2428 2429config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2430 def_bool y 2431 depends on X86_64 || X86_PAE 2432 2433config ARCH_ENABLE_HUGEPAGE_MIGRATION 2434 def_bool y 2435 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2436 2437config ARCH_ENABLE_THP_MIGRATION 2438 def_bool y 2439 depends on X86_64 && TRANSPARENT_HUGEPAGE 2440 2441menu "Power management and ACPI options" 2442 2443config ARCH_HIBERNATION_HEADER 2444 def_bool y 2445 depends on HIBERNATION 2446 2447source "kernel/power/Kconfig" 2448 2449source "drivers/acpi/Kconfig" 2450 2451source "drivers/sfi/Kconfig" 2452 2453config X86_APM_BOOT 2454 def_bool y 2455 depends on APM 2456 2457menuconfig APM 2458 tristate "APM (Advanced Power Management) BIOS support" 2459 depends on X86_32 && PM_SLEEP 2460 help 2461 APM is a BIOS specification for saving power using several different 2462 techniques. This is mostly useful for battery powered laptops with 2463 APM compliant BIOSes. If you say Y here, the system time will be 2464 reset after a RESUME operation, the /proc/apm device will provide 2465 battery status information, and user-space programs will receive 2466 notification of APM "events" (e.g. battery status change). 2467 2468 If you select "Y" here, you can disable actual use of the APM 2469 BIOS by passing the "apm=off" option to the kernel at boot time. 2470 2471 Note that the APM support is almost completely disabled for 2472 machines with more than one CPU. 2473 2474 In order to use APM, you will need supporting software. For location 2475 and more information, read <file:Documentation/power/apm-acpi.rst> 2476 and the Battery Powered Linux mini-HOWTO, available from 2477 <http://www.tldp.org/docs.html#howto>. 2478 2479 This driver does not spin down disk drives (see the hdparm(8) 2480 manpage ("man 8 hdparm") for that), and it doesn't turn off 2481 VESA-compliant "green" monitors. 2482 2483 This driver does not support the TI 4000M TravelMate and the ACER 2484 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2485 desktop machines also don't have compliant BIOSes, and this driver 2486 may cause those machines to panic during the boot phase. 2487 2488 Generally, if you don't have a battery in your machine, there isn't 2489 much point in using this driver and you should say N. If you get 2490 random kernel OOPSes or reboots that don't seem to be related to 2491 anything, try disabling/enabling this option (or disabling/enabling 2492 APM in your BIOS). 2493 2494 Some other things you should try when experiencing seemingly random, 2495 "weird" problems: 2496 2497 1) make sure that you have enough swap space and that it is 2498 enabled. 2499 2) pass the "no-hlt" option to the kernel 2500 3) switch on floating point emulation in the kernel and pass 2501 the "no387" option to the kernel 2502 4) pass the "floppy=nodma" option to the kernel 2503 5) pass the "mem=4M" option to the kernel (thereby disabling 2504 all but the first 4 MB of RAM) 2505 6) make sure that the CPU is not over clocked. 2506 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2507 8) disable the cache from your BIOS settings 2508 9) install a fan for the video card or exchange video RAM 2509 10) install a better fan for the CPU 2510 11) exchange RAM chips 2511 12) exchange the motherboard. 2512 2513 To compile this driver as a module, choose M here: the 2514 module will be called apm. 2515 2516if APM 2517 2518config APM_IGNORE_USER_SUSPEND 2519 bool "Ignore USER SUSPEND" 2520 help 2521 This option will ignore USER SUSPEND requests. On machines with a 2522 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2523 series notebooks, it is necessary to say Y because of a BIOS bug. 2524 2525config APM_DO_ENABLE 2526 bool "Enable PM at boot time" 2527 help 2528 Enable APM features at boot time. From page 36 of the APM BIOS 2529 specification: "When disabled, the APM BIOS does not automatically 2530 power manage devices, enter the Standby State, enter the Suspend 2531 State, or take power saving steps in response to CPU Idle calls." 2532 This driver will make CPU Idle calls when Linux is idle (unless this 2533 feature is turned off -- see "Do CPU IDLE calls", below). This 2534 should always save battery power, but more complicated APM features 2535 will be dependent on your BIOS implementation. You may need to turn 2536 this option off if your computer hangs at boot time when using APM 2537 support, or if it beeps continuously instead of suspending. Turn 2538 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2539 T400CDT. This is off by default since most machines do fine without 2540 this feature. 2541 2542config APM_CPU_IDLE 2543 depends on CPU_IDLE 2544 bool "Make CPU Idle calls when idle" 2545 help 2546 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2547 On some machines, this can activate improved power savings, such as 2548 a slowed CPU clock rate, when the machine is idle. These idle calls 2549 are made after the idle loop has run for some length of time (e.g., 2550 333 mS). On some machines, this will cause a hang at boot time or 2551 whenever the CPU becomes idle. (On machines with more than one CPU, 2552 this option does nothing.) 2553 2554config APM_DISPLAY_BLANK 2555 bool "Enable console blanking using APM" 2556 help 2557 Enable console blanking using the APM. Some laptops can use this to 2558 turn off the LCD backlight when the screen blanker of the Linux 2559 virtual console blanks the screen. Note that this is only used by 2560 the virtual console screen blanker, and won't turn off the backlight 2561 when using the X Window system. This also doesn't have anything to 2562 do with your VESA-compliant power-saving monitor. Further, this 2563 option doesn't work for all laptops -- it might not turn off your 2564 backlight at all, or it might print a lot of errors to the console, 2565 especially if you are using gpm. 2566 2567config APM_ALLOW_INTS 2568 bool "Allow interrupts during APM BIOS calls" 2569 help 2570 Normally we disable external interrupts while we are making calls to 2571 the APM BIOS as a measure to lessen the effects of a badly behaving 2572 BIOS implementation. The BIOS should reenable interrupts if it 2573 needs to. Unfortunately, some BIOSes do not -- especially those in 2574 many of the newer IBM Thinkpads. If you experience hangs when you 2575 suspend, try setting this to Y. Otherwise, say N. 2576 2577endif # APM 2578 2579source "drivers/cpufreq/Kconfig" 2580 2581source "drivers/cpuidle/Kconfig" 2582 2583source "drivers/idle/Kconfig" 2584 2585endmenu 2586 2587 2588menu "Bus options (PCI etc.)" 2589 2590choice 2591 prompt "PCI access mode" 2592 depends on X86_32 && PCI 2593 default PCI_GOANY 2594 help 2595 On PCI systems, the BIOS can be used to detect the PCI devices and 2596 determine their configuration. However, some old PCI motherboards 2597 have BIOS bugs and may crash if this is done. Also, some embedded 2598 PCI-based systems don't have any BIOS at all. Linux can also try to 2599 detect the PCI hardware directly without using the BIOS. 2600 2601 With this option, you can specify how Linux should detect the 2602 PCI devices. If you choose "BIOS", the BIOS will be used, 2603 if you choose "Direct", the BIOS won't be used, and if you 2604 choose "MMConfig", then PCI Express MMCONFIG will be used. 2605 If you choose "Any", the kernel will try MMCONFIG, then the 2606 direct access method and falls back to the BIOS if that doesn't 2607 work. If unsure, go with the default, which is "Any". 2608 2609config PCI_GOBIOS 2610 bool "BIOS" 2611 2612config PCI_GOMMCONFIG 2613 bool "MMConfig" 2614 2615config PCI_GODIRECT 2616 bool "Direct" 2617 2618config PCI_GOOLPC 2619 bool "OLPC XO-1" 2620 depends on OLPC 2621 2622config PCI_GOANY 2623 bool "Any" 2624 2625endchoice 2626 2627config PCI_BIOS 2628 def_bool y 2629 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2630 2631# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2632config PCI_DIRECT 2633 def_bool y 2634 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2635 2636config PCI_MMCONFIG 2637 bool "Support mmconfig PCI config space access" if X86_64 2638 default y 2639 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2640 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2641 2642config PCI_OLPC 2643 def_bool y 2644 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2645 2646config PCI_XEN 2647 def_bool y 2648 depends on PCI && XEN 2649 select SWIOTLB_XEN 2650 2651config MMCONF_FAM10H 2652 def_bool y 2653 depends on X86_64 && PCI_MMCONFIG && ACPI 2654 2655config PCI_CNB20LE_QUIRK 2656 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2657 depends on PCI 2658 help 2659 Read the PCI windows out of the CNB20LE host bridge. This allows 2660 PCI hotplug to work on systems with the CNB20LE chipset which do 2661 not have ACPI. 2662 2663 There's no public spec for this chipset, and this functionality 2664 is known to be incomplete. 2665 2666 You should say N unless you know you need this. 2667 2668config ISA_BUS 2669 bool "ISA bus support on modern systems" if EXPERT 2670 help 2671 Expose ISA bus device drivers and options available for selection and 2672 configuration. Enable this option if your target machine has an ISA 2673 bus. ISA is an older system, displaced by PCI and newer bus 2674 architectures -- if your target machine is modern, it probably does 2675 not have an ISA bus. 2676 2677 If unsure, say N. 2678 2679# x86_64 have no ISA slots, but can have ISA-style DMA. 2680config ISA_DMA_API 2681 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2682 default y 2683 help 2684 Enables ISA-style DMA support for devices requiring such controllers. 2685 If unsure, say Y. 2686 2687if X86_32 2688 2689config ISA 2690 bool "ISA support" 2691 help 2692 Find out whether you have ISA slots on your motherboard. ISA is the 2693 name of a bus system, i.e. the way the CPU talks to the other stuff 2694 inside your box. Other bus systems are PCI, EISA, MicroChannel 2695 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2696 newer boards don't support it. If you have ISA, say Y, otherwise N. 2697 2698config SCx200 2699 tristate "NatSemi SCx200 support" 2700 help 2701 This provides basic support for National Semiconductor's 2702 (now AMD's) Geode processors. The driver probes for the 2703 PCI-IDs of several on-chip devices, so its a good dependency 2704 for other scx200_* drivers. 2705 2706 If compiled as a module, the driver is named scx200. 2707 2708config SCx200HR_TIMER 2709 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2710 depends on SCx200 2711 default y 2712 help 2713 This driver provides a clocksource built upon the on-chip 2714 27MHz high-resolution timer. Its also a workaround for 2715 NSC Geode SC-1100's buggy TSC, which loses time when the 2716 processor goes idle (as is done by the scheduler). The 2717 other workaround is idle=poll boot option. 2718 2719config OLPC 2720 bool "One Laptop Per Child support" 2721 depends on !X86_PAE 2722 select GPIOLIB 2723 select OF 2724 select OF_PROMTREE 2725 select IRQ_DOMAIN 2726 select OLPC_EC 2727 help 2728 Add support for detecting the unique features of the OLPC 2729 XO hardware. 2730 2731config OLPC_XO1_PM 2732 bool "OLPC XO-1 Power Management" 2733 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2734 help 2735 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2736 2737config OLPC_XO1_RTC 2738 bool "OLPC XO-1 Real Time Clock" 2739 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2740 help 2741 Add support for the XO-1 real time clock, which can be used as a 2742 programmable wakeup source. 2743 2744config OLPC_XO1_SCI 2745 bool "OLPC XO-1 SCI extras" 2746 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2747 depends on INPUT=y 2748 select POWER_SUPPLY 2749 help 2750 Add support for SCI-based features of the OLPC XO-1 laptop: 2751 - EC-driven system wakeups 2752 - Power button 2753 - Ebook switch 2754 - Lid switch 2755 - AC adapter status updates 2756 - Battery status updates 2757 2758config OLPC_XO15_SCI 2759 bool "OLPC XO-1.5 SCI extras" 2760 depends on OLPC && ACPI 2761 select POWER_SUPPLY 2762 help 2763 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2764 - EC-driven system wakeups 2765 - AC adapter status updates 2766 - Battery status updates 2767 2768config ALIX 2769 bool "PCEngines ALIX System Support (LED setup)" 2770 select GPIOLIB 2771 help 2772 This option enables system support for the PCEngines ALIX. 2773 At present this just sets up LEDs for GPIO control on 2774 ALIX2/3/6 boards. However, other system specific setup should 2775 get added here. 2776 2777 Note: You must still enable the drivers for GPIO and LED support 2778 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2779 2780 Note: You have to set alix.force=1 for boards with Award BIOS. 2781 2782config NET5501 2783 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2784 select GPIOLIB 2785 help 2786 This option enables system support for the Soekris Engineering net5501. 2787 2788config GEOS 2789 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2790 select GPIOLIB 2791 depends on DMI 2792 help 2793 This option enables system support for the Traverse Technologies GEOS. 2794 2795config TS5500 2796 bool "Technologic Systems TS-5500 platform support" 2797 depends on MELAN 2798 select CHECK_SIGNATURE 2799 select NEW_LEDS 2800 select LEDS_CLASS 2801 help 2802 This option enables system support for the Technologic Systems TS-5500. 2803 2804endif # X86_32 2805 2806config AMD_NB 2807 def_bool y 2808 depends on CPU_SUP_AMD && PCI 2809 2810config X86_SYSFB 2811 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2812 help 2813 Firmwares often provide initial graphics framebuffers so the BIOS, 2814 bootloader or kernel can show basic video-output during boot for 2815 user-guidance and debugging. Historically, x86 used the VESA BIOS 2816 Extensions and EFI-framebuffers for this, which are mostly limited 2817 to x86. 2818 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2819 framebuffers so the new generic system-framebuffer drivers can be 2820 used on x86. If the framebuffer is not compatible with the generic 2821 modes, it is advertised as fallback platform framebuffer so legacy 2822 drivers like efifb, vesafb and uvesafb can pick it up. 2823 If this option is not selected, all system framebuffers are always 2824 marked as fallback platform framebuffers as usual. 2825 2826 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2827 not be able to pick up generic system framebuffers if this option 2828 is selected. You are highly encouraged to enable simplefb as 2829 replacement if you select this option. simplefb can correctly deal 2830 with generic system framebuffers. But you should still keep vesafb 2831 and others enabled as fallback if a system framebuffer is 2832 incompatible with simplefb. 2833 2834 If unsure, say Y. 2835 2836endmenu 2837 2838 2839menu "Binary Emulations" 2840 2841config IA32_EMULATION 2842 bool "IA32 Emulation" 2843 depends on X86_64 2844 select ARCH_WANT_OLD_COMPAT_IPC 2845 select BINFMT_ELF 2846 select COMPAT_BINFMT_ELF 2847 select COMPAT_OLD_SIGACTION 2848 help 2849 Include code to run legacy 32-bit programs under a 2850 64-bit kernel. You should likely turn this on, unless you're 2851 100% sure that you don't have any 32-bit programs left. 2852 2853config IA32_AOUT 2854 tristate "IA32 a.out support" 2855 depends on IA32_EMULATION 2856 depends on BROKEN 2857 help 2858 Support old a.out binaries in the 32bit emulation. 2859 2860config X86_X32 2861 bool "x32 ABI for 64-bit mode" 2862 depends on X86_64 2863 help 2864 Include code to run binaries for the x32 native 32-bit ABI 2865 for 64-bit processors. An x32 process gets access to the 2866 full 64-bit register file and wide data path while leaving 2867 pointers at 32 bits for smaller memory footprint. 2868 2869 You will need a recent binutils (2.22 or later) with 2870 elf32_x86_64 support enabled to compile a kernel with this 2871 option set. 2872 2873config COMPAT_32 2874 def_bool y 2875 depends on IA32_EMULATION || X86_32 2876 select HAVE_UID16 2877 select OLD_SIGSUSPEND3 2878 2879config COMPAT 2880 def_bool y 2881 depends on IA32_EMULATION || X86_X32 2882 2883if COMPAT 2884config COMPAT_FOR_U64_ALIGNMENT 2885 def_bool y 2886 2887config SYSVIPC_COMPAT 2888 def_bool y 2889 depends on SYSVIPC 2890endif 2891 2892endmenu 2893 2894 2895config HAVE_ATOMIC_IOMAP 2896 def_bool y 2897 depends on X86_32 2898 2899source "drivers/firmware/Kconfig" 2900 2901source "arch/x86/kvm/Kconfig" 2902 2903source "arch/x86/Kconfig.assembler" 2904