1# SPDX-License-Identifier: GPL-2.0 2# Select 32 or 64 bit 3config 64BIT 4 bool "64-bit kernel" if "$(ARCH)" = "x86" 5 default "$(ARCH)" != "i386" 6 help 7 Say yes to build a 64-bit kernel - formerly known as x86_64 8 Say no to build a 32-bit kernel - formerly known as i386 9 10config X86_32 11 def_bool y 12 depends on !64BIT 13 # Options that are inherently 32-bit kernel only: 14 select ARCH_WANT_IPC_PARSE_VERSION 15 select CLKSRC_I8253 16 select CLONE_BACKWARDS 17 select GENERIC_VDSO_32 18 select HAVE_DEBUG_STACKOVERFLOW 19 select KMAP_LOCAL 20 select MODULES_USE_ELF_REL 21 select OLD_SIGACTION 22 select ARCH_SPLIT_ARG64 23 24config X86_64 25 def_bool y 26 depends on 64BIT 27 # Options that are inherently 64-bit kernel only: 28 select ARCH_HAS_GIGANTIC_PAGE 29 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 30 select ARCH_USE_CMPXCHG_LOCKREF 31 select HAVE_ARCH_SOFT_DIRTY 32 select MODULES_USE_ELF_RELA 33 select NEED_DMA_MAP_STATE 34 select SWIOTLB 35 select ARCH_HAS_ELFCORE_COMPAT 36 37config FORCE_DYNAMIC_FTRACE 38 def_bool y 39 depends on X86_32 40 depends on FUNCTION_TRACER 41 select DYNAMIC_FTRACE 42 help 43 We keep the static function tracing (!DYNAMIC_FTRACE) around 44 in order to test the non static function tracing in the 45 generic code, as other architectures still use it. But we 46 only need to keep it around for x86_64. No need to keep it 47 for x86_32. For x86_32, force DYNAMIC_FTRACE. 48# 49# Arch settings 50# 51# ( Note that options that are marked 'if X86_64' could in principle be 52# ported to 32-bit as well. ) 53# 54config X86 55 def_bool y 56 # 57 # Note: keep this list sorted alphabetically 58 # 59 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 60 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 61 select ARCH_32BIT_OFF_T if X86_32 62 select ARCH_CLOCKSOURCE_INIT 63 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 64 select ARCH_HAS_DEBUG_VIRTUAL 65 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 66 select ARCH_HAS_DEVMEM_IS_ALLOWED 67 select ARCH_HAS_EARLY_DEBUG if KGDB 68 select ARCH_HAS_ELF_RANDOMIZE 69 select ARCH_HAS_FAST_MULTIPLIER 70 select ARCH_HAS_FILTER_PGPROT 71 select ARCH_HAS_FORTIFY_SOURCE 72 select ARCH_HAS_GCOV_PROFILE_ALL 73 select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION 74 select ARCH_HAS_MEM_ENCRYPT 75 select ARCH_HAS_MEMBARRIER_SYNC_CORE 76 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 77 select ARCH_HAS_PMEM_API if X86_64 78 select ARCH_HAS_PTE_DEVMAP if X86_64 79 select ARCH_HAS_PTE_SPECIAL 80 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 81 select ARCH_HAS_COPY_MC if X86_64 82 select ARCH_HAS_SET_MEMORY 83 select ARCH_HAS_SET_DIRECT_MAP 84 select ARCH_HAS_STRICT_KERNEL_RWX 85 select ARCH_HAS_STRICT_MODULE_RWX 86 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 87 select ARCH_HAS_SYSCALL_WRAPPER 88 select ARCH_HAS_UBSAN_SANITIZE_ALL 89 select ARCH_HAS_DEBUG_WX 90 select ARCH_HAVE_NMI_SAFE_CMPXCHG 91 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 92 select ARCH_MIGHT_HAVE_PC_PARPORT 93 select ARCH_MIGHT_HAVE_PC_SERIO 94 select ARCH_STACKWALK 95 select ARCH_SUPPORTS_ACPI 96 select ARCH_SUPPORTS_ATOMIC_RMW 97 select ARCH_SUPPORTS_DEBUG_PAGEALLOC 98 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 99 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 100 select ARCH_SUPPORTS_LTO_CLANG if X86_64 101 select ARCH_SUPPORTS_LTO_CLANG_THIN if X86_64 102 select ARCH_USE_BUILTIN_BSWAP 103 select ARCH_USE_MEMTEST 104 select ARCH_USE_QUEUED_RWLOCKS 105 select ARCH_USE_QUEUED_SPINLOCKS 106 select ARCH_USE_SYM_ANNOTATIONS 107 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 108 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 109 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 110 select ARCH_WANT_HUGE_PMD_SHARE 111 select ARCH_WANT_LD_ORPHAN_WARN 112 select ARCH_WANTS_THP_SWAP if X86_64 113 select BUILDTIME_TABLE_SORT 114 select CLKEVT_I8253 115 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 116 select CLOCKSOURCE_WATCHDOG 117 select DCACHE_WORD_ACCESS 118 select EDAC_ATOMIC_SCRUB 119 select EDAC_SUPPORT 120 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 121 select GENERIC_CLOCKEVENTS_MIN_ADJUST 122 select GENERIC_CMOS_UPDATE 123 select GENERIC_CPU_AUTOPROBE 124 select GENERIC_CPU_VULNERABILITIES 125 select GENERIC_EARLY_IOREMAP 126 select GENERIC_ENTRY 127 select GENERIC_FIND_FIRST_BIT 128 select GENERIC_IOMAP 129 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 130 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 131 select GENERIC_IRQ_MIGRATION if SMP 132 select GENERIC_IRQ_PROBE 133 select GENERIC_IRQ_RESERVATION_MODE 134 select GENERIC_IRQ_SHOW 135 select GENERIC_PENDING_IRQ if SMP 136 select GENERIC_PTDUMP 137 select GENERIC_SMP_IDLE_THREAD 138 select GENERIC_STRNCPY_FROM_USER 139 select GENERIC_STRNLEN_USER 140 select GENERIC_TIME_VSYSCALL 141 select GENERIC_GETTIMEOFDAY 142 select GENERIC_VDSO_TIME_NS 143 select GUP_GET_PTE_LOW_HIGH if X86_PAE 144 select HARDIRQS_SW_RESEND 145 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 146 select HAVE_ACPI_APEI if ACPI 147 select HAVE_ACPI_APEI_NMI if ACPI 148 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 149 select HAVE_ARCH_AUDITSYSCALL 150 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 151 select HAVE_ARCH_JUMP_LABEL 152 select HAVE_ARCH_JUMP_LABEL_RELATIVE 153 select HAVE_ARCH_KASAN if X86_64 154 select HAVE_ARCH_KASAN_VMALLOC if X86_64 155 select HAVE_ARCH_KFENCE 156 select HAVE_ARCH_KGDB 157 select HAVE_ARCH_MMAP_RND_BITS if MMU 158 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 159 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 160 select HAVE_ARCH_PREL32_RELOCATIONS 161 select HAVE_ARCH_SECCOMP_FILTER 162 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 163 select HAVE_ARCH_STACKLEAK 164 select HAVE_ARCH_TRACEHOOK 165 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 166 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 167 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 168 select HAVE_ARCH_VMAP_STACK if X86_64 169 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 170 select HAVE_ARCH_WITHIN_STACK_FRAMES 171 select HAVE_ASM_MODVERSIONS 172 select HAVE_CMPXCHG_DOUBLE 173 select HAVE_CMPXCHG_LOCAL 174 select HAVE_CONTEXT_TRACKING if X86_64 175 select HAVE_CONTEXT_TRACKING_OFFSTACK if HAVE_CONTEXT_TRACKING 176 select HAVE_C_RECORDMCOUNT 177 select HAVE_OBJTOOL_MCOUNT if STACK_VALIDATION 178 select HAVE_DEBUG_KMEMLEAK 179 select HAVE_DMA_CONTIGUOUS 180 select HAVE_DYNAMIC_FTRACE 181 select HAVE_DYNAMIC_FTRACE_WITH_REGS 182 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 183 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 184 select HAVE_EBPF_JIT 185 select HAVE_EFFICIENT_UNALIGNED_ACCESS 186 select HAVE_EISA 187 select HAVE_EXIT_THREAD 188 select HAVE_FAST_GUP 189 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 190 select HAVE_FTRACE_MCOUNT_RECORD 191 select HAVE_FUNCTION_GRAPH_TRACER 192 select HAVE_FUNCTION_TRACER 193 select HAVE_GCC_PLUGINS 194 select HAVE_HW_BREAKPOINT 195 select HAVE_IDE 196 select HAVE_IOREMAP_PROT 197 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 198 select HAVE_IRQ_TIME_ACCOUNTING 199 select HAVE_KERNEL_BZIP2 200 select HAVE_KERNEL_GZIP 201 select HAVE_KERNEL_LZ4 202 select HAVE_KERNEL_LZMA 203 select HAVE_KERNEL_LZO 204 select HAVE_KERNEL_XZ 205 select HAVE_KERNEL_ZSTD 206 select HAVE_KPROBES 207 select HAVE_KPROBES_ON_FTRACE 208 select HAVE_FUNCTION_ERROR_INJECTION 209 select HAVE_KRETPROBES 210 select HAVE_KVM 211 select HAVE_LIVEPATCH if X86_64 212 select HAVE_MIXED_BREAKPOINTS_REGS 213 select HAVE_MOD_ARCH_SPECIFIC 214 select HAVE_MOVE_PMD 215 select HAVE_MOVE_PUD 216 select HAVE_NMI 217 select HAVE_OPTPROBES 218 select HAVE_PCSPKR_PLATFORM 219 select HAVE_PERF_EVENTS 220 select HAVE_PERF_EVENTS_NMI 221 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 222 select HAVE_PCI 223 select HAVE_PERF_REGS 224 select HAVE_PERF_USER_STACK_DUMP 225 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 226 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 227 select HAVE_REGS_AND_STACK_ACCESS_API 228 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 229 select HAVE_FUNCTION_ARG_ACCESS_API 230 select HAVE_SOFTIRQ_ON_OWN_STACK 231 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 232 select HAVE_STACK_VALIDATION if X86_64 233 select HAVE_STATIC_CALL 234 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION 235 select HAVE_PREEMPT_DYNAMIC 236 select HAVE_RSEQ 237 select HAVE_SYSCALL_TRACEPOINTS 238 select HAVE_UNSTABLE_SCHED_CLOCK 239 select HAVE_USER_RETURN_NOTIFIER 240 select HAVE_GENERIC_VDSO 241 select HOTPLUG_SMT if SMP 242 select IRQ_FORCED_THREADING 243 select NEED_SG_DMA_LENGTH 244 select PCI_DOMAINS if PCI 245 select PCI_LOCKLESS_CONFIG if PCI 246 select PERF_EVENTS 247 select RTC_LIB 248 select RTC_MC146818_LIB 249 select SPARSE_IRQ 250 select SRCU 251 select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE) 252 select SYSCTL_EXCEPTION_TRACE 253 select THREAD_INFO_IN_TASK 254 select USER_STACKTRACE_SUPPORT 255 select VIRT_TO_BUS 256 select HAVE_ARCH_KCSAN if X86_64 257 select X86_FEATURE_NAMES if PROC_FS 258 select PROC_PID_ARCH_STATUS if PROC_FS 259 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 260 261config INSTRUCTION_DECODER 262 def_bool y 263 depends on KPROBES || PERF_EVENTS || UPROBES 264 265config OUTPUT_FORMAT 266 string 267 default "elf32-i386" if X86_32 268 default "elf64-x86-64" if X86_64 269 270config LOCKDEP_SUPPORT 271 def_bool y 272 273config STACKTRACE_SUPPORT 274 def_bool y 275 276config MMU 277 def_bool y 278 279config ARCH_MMAP_RND_BITS_MIN 280 default 28 if 64BIT 281 default 8 282 283config ARCH_MMAP_RND_BITS_MAX 284 default 32 if 64BIT 285 default 16 286 287config ARCH_MMAP_RND_COMPAT_BITS_MIN 288 default 8 289 290config ARCH_MMAP_RND_COMPAT_BITS_MAX 291 default 16 292 293config SBUS 294 bool 295 296config GENERIC_ISA_DMA 297 def_bool y 298 depends on ISA_DMA_API 299 300config GENERIC_BUG 301 def_bool y 302 depends on BUG 303 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 304 305config GENERIC_BUG_RELATIVE_POINTERS 306 bool 307 308config ARCH_MAY_HAVE_PC_FDC 309 def_bool y 310 depends on ISA_DMA_API 311 312config GENERIC_CALIBRATE_DELAY 313 def_bool y 314 315config ARCH_HAS_CPU_RELAX 316 def_bool y 317 318config ARCH_HAS_CACHE_LINE_SIZE 319 def_bool y 320 321config ARCH_HAS_FILTER_PGPROT 322 def_bool y 323 324config HAVE_SETUP_PER_CPU_AREA 325 def_bool y 326 327config NEED_PER_CPU_EMBED_FIRST_CHUNK 328 def_bool y 329 330config NEED_PER_CPU_PAGE_FIRST_CHUNK 331 def_bool y 332 333config ARCH_HIBERNATION_POSSIBLE 334 def_bool y 335 336config ARCH_SUSPEND_POSSIBLE 337 def_bool y 338 339config ARCH_WANT_GENERAL_HUGETLB 340 def_bool y 341 342config ZONE_DMA32 343 def_bool y if X86_64 344 345config AUDIT_ARCH 346 def_bool y if X86_64 347 348config KASAN_SHADOW_OFFSET 349 hex 350 depends on KASAN 351 default 0xdffffc0000000000 352 353config HAVE_INTEL_TXT 354 def_bool y 355 depends on INTEL_IOMMU && ACPI 356 357config X86_32_SMP 358 def_bool y 359 depends on X86_32 && SMP 360 361config X86_64_SMP 362 def_bool y 363 depends on X86_64 && SMP 364 365config ARCH_SUPPORTS_UPROBES 366 def_bool y 367 368config FIX_EARLYCON_MEM 369 def_bool y 370 371config DYNAMIC_PHYSICAL_MASK 372 bool 373 374config PGTABLE_LEVELS 375 int 376 default 5 if X86_5LEVEL 377 default 4 if X86_64 378 default 3 if X86_PAE 379 default 2 380 381config CC_HAS_SANE_STACKPROTECTOR 382 bool 383 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 384 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 385 help 386 We have to make sure stack protector is unconditionally disabled if 387 the compiler produces broken code or if it does not let us control 388 the segment on 32-bit kernels. 389 390menu "Processor type and features" 391 392config ZONE_DMA 393 bool "DMA memory allocation support" if EXPERT 394 default y 395 help 396 DMA memory allocation support allows devices with less than 32-bit 397 addressing to allocate within the first 16MB of address space. 398 Disable if no such devices will be used. 399 400 If unsure, say Y. 401 402config SMP 403 bool "Symmetric multi-processing support" 404 help 405 This enables support for systems with more than one CPU. If you have 406 a system with only one CPU, say N. If you have a system with more 407 than one CPU, say Y. 408 409 If you say N here, the kernel will run on uni- and multiprocessor 410 machines, but will use only one CPU of a multiprocessor machine. If 411 you say Y here, the kernel will run on many, but not all, 412 uniprocessor machines. On a uniprocessor machine, the kernel 413 will run faster if you say N here. 414 415 Note that if you say Y here and choose architecture "586" or 416 "Pentium" under "Processor family", the kernel will not work on 486 417 architectures. Similarly, multiprocessor kernels for the "PPro" 418 architecture may not work on all Pentium based boards. 419 420 People using multiprocessor machines who say Y here should also say 421 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 422 Management" code will be disabled if you say Y here. 423 424 See also <file:Documentation/x86/i386/IO-APIC.rst>, 425 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 426 <http://www.tldp.org/docs.html#howto>. 427 428 If you don't know what to do here, say N. 429 430config X86_FEATURE_NAMES 431 bool "Processor feature human-readable names" if EMBEDDED 432 default y 433 help 434 This option compiles in a table of x86 feature bits and corresponding 435 names. This is required to support /proc/cpuinfo and a few kernel 436 messages. You can disable this to save space, at the expense of 437 making those few kernel messages show numeric feature bits instead. 438 439 If in doubt, say Y. 440 441config X86_X2APIC 442 bool "Support x2apic" 443 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 444 help 445 This enables x2apic support on CPUs that have this feature. 446 447 This allows 32-bit apic IDs (so it can support very large systems), 448 and accesses the local apic via MSRs not via mmio. 449 450 If you don't know what to do here, say N. 451 452config X86_MPPARSE 453 bool "Enable MPS table" if ACPI 454 default y 455 depends on X86_LOCAL_APIC 456 help 457 For old smp systems that do not have proper acpi support. Newer systems 458 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 459 460config GOLDFISH 461 def_bool y 462 depends on X86_GOLDFISH 463 464config RETPOLINE 465 bool "Avoid speculative indirect branches in kernel" 466 default y 467 help 468 Compile kernel with the retpoline compiler options to guard against 469 kernel-to-user data leaks by avoiding speculative indirect 470 branches. Requires a compiler with -mindirect-branch=thunk-extern 471 support for full protection. The kernel may run slower. 472 473config X86_CPU_RESCTRL 474 bool "x86 CPU resource control support" 475 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 476 select KERNFS 477 select PROC_CPU_RESCTRL if PROC_FS 478 help 479 Enable x86 CPU resource control support. 480 481 Provide support for the allocation and monitoring of system resources 482 usage by the CPU. 483 484 Intel calls this Intel Resource Director Technology 485 (Intel(R) RDT). More information about RDT can be found in the 486 Intel x86 Architecture Software Developer Manual. 487 488 AMD calls this AMD Platform Quality of Service (AMD QoS). 489 More information about AMD QoS can be found in the AMD64 Technology 490 Platform Quality of Service Extensions manual. 491 492 Say N if unsure. 493 494if X86_32 495config X86_BIGSMP 496 bool "Support for big SMP systems with more than 8 CPUs" 497 depends on SMP 498 help 499 This option is needed for the systems that have more than 8 CPUs. 500 501config X86_EXTENDED_PLATFORM 502 bool "Support for extended (non-PC) x86 platforms" 503 default y 504 help 505 If you disable this option then the kernel will only support 506 standard PC platforms. (which covers the vast majority of 507 systems out there.) 508 509 If you enable this option then you'll be able to select support 510 for the following (non-PC) 32 bit x86 platforms: 511 Goldfish (Android emulator) 512 AMD Elan 513 RDC R-321x SoC 514 SGI 320/540 (Visual Workstation) 515 STA2X11-based (e.g. Northville) 516 Moorestown MID devices 517 518 If you have one of these systems, or if you want to build a 519 generic distribution kernel, say Y here - otherwise say N. 520endif 521 522if X86_64 523config X86_EXTENDED_PLATFORM 524 bool "Support for extended (non-PC) x86 platforms" 525 default y 526 help 527 If you disable this option then the kernel will only support 528 standard PC platforms. (which covers the vast majority of 529 systems out there.) 530 531 If you enable this option then you'll be able to select support 532 for the following (non-PC) 64 bit x86 platforms: 533 Numascale NumaChip 534 ScaleMP vSMP 535 SGI Ultraviolet 536 537 If you have one of these systems, or if you want to build a 538 generic distribution kernel, say Y here - otherwise say N. 539endif 540# This is an alphabetically sorted list of 64 bit extended platforms 541# Please maintain the alphabetic order if and when there are additions 542config X86_NUMACHIP 543 bool "Numascale NumaChip" 544 depends on X86_64 545 depends on X86_EXTENDED_PLATFORM 546 depends on NUMA 547 depends on SMP 548 depends on X86_X2APIC 549 depends on PCI_MMCONFIG 550 help 551 Adds support for Numascale NumaChip large-SMP systems. Needed to 552 enable more than ~168 cores. 553 If you don't have one of these, you should say N here. 554 555config X86_VSMP 556 bool "ScaleMP vSMP" 557 select HYPERVISOR_GUEST 558 select PARAVIRT 559 depends on X86_64 && PCI 560 depends on X86_EXTENDED_PLATFORM 561 depends on SMP 562 help 563 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 564 supposed to run on these EM64T-based machines. Only choose this option 565 if you have one of these machines. 566 567config X86_UV 568 bool "SGI Ultraviolet" 569 depends on X86_64 570 depends on X86_EXTENDED_PLATFORM 571 depends on NUMA 572 depends on EFI 573 depends on KEXEC_CORE 574 depends on X86_X2APIC 575 depends on PCI 576 help 577 This option is needed in order to support SGI Ultraviolet systems. 578 If you don't have one of these, you should say N here. 579 580# Following is an alphabetically sorted list of 32 bit extended platforms 581# Please maintain the alphabetic order if and when there are additions 582 583config X86_GOLDFISH 584 bool "Goldfish (Virtual Platform)" 585 depends on X86_EXTENDED_PLATFORM 586 help 587 Enable support for the Goldfish virtual platform used primarily 588 for Android development. Unless you are building for the Android 589 Goldfish emulator say N here. 590 591config X86_INTEL_CE 592 bool "CE4100 TV platform" 593 depends on PCI 594 depends on PCI_GODIRECT 595 depends on X86_IO_APIC 596 depends on X86_32 597 depends on X86_EXTENDED_PLATFORM 598 select X86_REBOOTFIXUPS 599 select OF 600 select OF_EARLY_FLATTREE 601 help 602 Select for the Intel CE media processor (CE4100) SOC. 603 This option compiles in support for the CE4100 SOC for settop 604 boxes and media devices. 605 606config X86_INTEL_MID 607 bool "Intel MID platform support" 608 depends on X86_EXTENDED_PLATFORM 609 depends on X86_PLATFORM_DEVICES 610 depends on PCI 611 depends on X86_64 || (PCI_GOANY && X86_32) 612 depends on X86_IO_APIC 613 select I2C 614 select DW_APB_TIMER 615 select APB_TIMER 616 select INTEL_SCU_PCI 617 select MFD_INTEL_MSIC 618 help 619 Select to build a kernel capable of supporting Intel MID (Mobile 620 Internet Device) platform systems which do not have the PCI legacy 621 interfaces. If you are building for a PC class system say N here. 622 623 Intel MID platforms are based on an Intel processor and chipset which 624 consume less power than most of the x86 derivatives. 625 626config X86_INTEL_QUARK 627 bool "Intel Quark platform support" 628 depends on X86_32 629 depends on X86_EXTENDED_PLATFORM 630 depends on X86_PLATFORM_DEVICES 631 depends on X86_TSC 632 depends on PCI 633 depends on PCI_GOANY 634 depends on X86_IO_APIC 635 select IOSF_MBI 636 select INTEL_IMR 637 select COMMON_CLK 638 help 639 Select to include support for Quark X1000 SoC. 640 Say Y here if you have a Quark based system such as the Arduino 641 compatible Intel Galileo. 642 643config X86_INTEL_LPSS 644 bool "Intel Low Power Subsystem Support" 645 depends on X86 && ACPI && PCI 646 select COMMON_CLK 647 select PINCTRL 648 select IOSF_MBI 649 help 650 Select to build support for Intel Low Power Subsystem such as 651 found on Intel Lynxpoint PCH. Selecting this option enables 652 things like clock tree (common clock framework) and pincontrol 653 which are needed by the LPSS peripheral drivers. 654 655config X86_AMD_PLATFORM_DEVICE 656 bool "AMD ACPI2Platform devices support" 657 depends on ACPI 658 select COMMON_CLK 659 select PINCTRL 660 help 661 Select to interpret AMD specific ACPI device to platform device 662 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 663 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 664 implemented under PINCTRL subsystem. 665 666config IOSF_MBI 667 tristate "Intel SoC IOSF Sideband support for SoC platforms" 668 depends on PCI 669 help 670 This option enables sideband register access support for Intel SoC 671 platforms. On these platforms the IOSF sideband is used in lieu of 672 MSR's for some register accesses, mostly but not limited to thermal 673 and power. Drivers may query the availability of this device to 674 determine if they need the sideband in order to work on these 675 platforms. The sideband is available on the following SoC products. 676 This list is not meant to be exclusive. 677 - BayTrail 678 - Braswell 679 - Quark 680 681 You should say Y if you are running a kernel on one of these SoC's. 682 683config IOSF_MBI_DEBUG 684 bool "Enable IOSF sideband access through debugfs" 685 depends on IOSF_MBI && DEBUG_FS 686 help 687 Select this option to expose the IOSF sideband access registers (MCR, 688 MDR, MCRX) through debugfs to write and read register information from 689 different units on the SoC. This is most useful for obtaining device 690 state information for debug and analysis. As this is a general access 691 mechanism, users of this option would have specific knowledge of the 692 device they want to access. 693 694 If you don't require the option or are in doubt, say N. 695 696config X86_RDC321X 697 bool "RDC R-321x SoC" 698 depends on X86_32 699 depends on X86_EXTENDED_PLATFORM 700 select M486 701 select X86_REBOOTFIXUPS 702 help 703 This option is needed for RDC R-321x system-on-chip, also known 704 as R-8610-(G). 705 If you don't have one of these chips, you should say N here. 706 707config X86_32_NON_STANDARD 708 bool "Support non-standard 32-bit SMP architectures" 709 depends on X86_32 && SMP 710 depends on X86_EXTENDED_PLATFORM 711 help 712 This option compiles in the bigsmp and STA2X11 default 713 subarchitectures. It is intended for a generic binary 714 kernel. If you select them all, kernel will probe it one by 715 one and will fallback to default. 716 717# Alphabetically sorted list of Non standard 32 bit platforms 718 719config X86_SUPPORTS_MEMORY_FAILURE 720 def_bool y 721 # MCE code calls memory_failure(): 722 depends on X86_MCE 723 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 724 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 725 depends on X86_64 || !SPARSEMEM 726 select ARCH_SUPPORTS_MEMORY_FAILURE 727 728config STA2X11 729 bool "STA2X11 Companion Chip Support" 730 depends on X86_32_NON_STANDARD && PCI 731 select SWIOTLB 732 select MFD_STA2X11 733 select GPIOLIB 734 help 735 This adds support for boards based on the STA2X11 IO-Hub, 736 a.k.a. "ConneXt". The chip is used in place of the standard 737 PC chipset, so all "standard" peripherals are missing. If this 738 option is selected the kernel will still be able to boot on 739 standard PC machines. 740 741config X86_32_IRIS 742 tristate "Eurobraille/Iris poweroff module" 743 depends on X86_32 744 help 745 The Iris machines from EuroBraille do not have APM or ACPI support 746 to shut themselves down properly. A special I/O sequence is 747 needed to do so, which is what this module does at 748 kernel shutdown. 749 750 This is only for Iris machines from EuroBraille. 751 752 If unused, say N. 753 754config SCHED_OMIT_FRAME_POINTER 755 def_bool y 756 prompt "Single-depth WCHAN output" 757 depends on X86 758 help 759 Calculate simpler /proc/<PID>/wchan values. If this option 760 is disabled then wchan values will recurse back to the 761 caller function. This provides more accurate wchan values, 762 at the expense of slightly more scheduling overhead. 763 764 If in doubt, say "Y". 765 766menuconfig HYPERVISOR_GUEST 767 bool "Linux guest support" 768 help 769 Say Y here to enable options for running Linux under various hyper- 770 visors. This option enables basic hypervisor detection and platform 771 setup. 772 773 If you say N, all options in this submenu will be skipped and 774 disabled, and Linux guest support won't be built in. 775 776if HYPERVISOR_GUEST 777 778config PARAVIRT 779 bool "Enable paravirtualization code" 780 depends on HAVE_STATIC_CALL 781 help 782 This changes the kernel so it can modify itself when it is run 783 under a hypervisor, potentially improving performance significantly 784 over full virtualization. However, when run without a hypervisor 785 the kernel is theoretically slower and slightly larger. 786 787config PARAVIRT_XXL 788 bool 789 790config PARAVIRT_DEBUG 791 bool "paravirt-ops debugging" 792 depends on PARAVIRT && DEBUG_KERNEL 793 help 794 Enable to debug paravirt_ops internals. Specifically, BUG if 795 a paravirt_op is missing when it is called. 796 797config PARAVIRT_SPINLOCKS 798 bool "Paravirtualization layer for spinlocks" 799 depends on PARAVIRT && SMP 800 help 801 Paravirtualized spinlocks allow a pvops backend to replace the 802 spinlock implementation with something virtualization-friendly 803 (for example, block the virtual CPU rather than spinning). 804 805 It has a minimal impact on native kernels and gives a nice performance 806 benefit on paravirtualized KVM / Xen kernels. 807 808 If you are unsure how to answer this question, answer Y. 809 810config X86_HV_CALLBACK_VECTOR 811 def_bool n 812 813source "arch/x86/xen/Kconfig" 814 815config KVM_GUEST 816 bool "KVM Guest support (including kvmclock)" 817 depends on PARAVIRT 818 select PARAVIRT_CLOCK 819 select ARCH_CPUIDLE_HALTPOLL 820 select X86_HV_CALLBACK_VECTOR 821 default y 822 help 823 This option enables various optimizations for running under the KVM 824 hypervisor. It includes a paravirtualized clock, so that instead 825 of relying on a PIT (or probably other) emulation by the 826 underlying device model, the host provides the guest with 827 timing infrastructure such as time of day, and system time 828 829config ARCH_CPUIDLE_HALTPOLL 830 def_bool n 831 prompt "Disable host haltpoll when loading haltpoll driver" 832 help 833 If virtualized under KVM, disable host haltpoll. 834 835config PVH 836 bool "Support for running PVH guests" 837 help 838 This option enables the PVH entry point for guest virtual machines 839 as specified in the x86/HVM direct boot ABI. 840 841config PARAVIRT_TIME_ACCOUNTING 842 bool "Paravirtual steal time accounting" 843 depends on PARAVIRT 844 help 845 Select this option to enable fine granularity task steal time 846 accounting. Time spent executing other tasks in parallel with 847 the current vCPU is discounted from the vCPU power. To account for 848 that, there can be a small performance impact. 849 850 If in doubt, say N here. 851 852config PARAVIRT_CLOCK 853 bool 854 855config JAILHOUSE_GUEST 856 bool "Jailhouse non-root cell support" 857 depends on X86_64 && PCI 858 select X86_PM_TIMER 859 help 860 This option allows to run Linux as guest in a Jailhouse non-root 861 cell. You can leave this option disabled if you only want to start 862 Jailhouse and run Linux afterwards in the root cell. 863 864config ACRN_GUEST 865 bool "ACRN Guest support" 866 depends on X86_64 867 select X86_HV_CALLBACK_VECTOR 868 help 869 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 870 a flexible, lightweight reference open-source hypervisor, built with 871 real-time and safety-criticality in mind. It is built for embedded 872 IOT with small footprint and real-time features. More details can be 873 found in https://projectacrn.org/. 874 875endif #HYPERVISOR_GUEST 876 877source "arch/x86/Kconfig.cpu" 878 879config HPET_TIMER 880 def_bool X86_64 881 prompt "HPET Timer Support" if X86_32 882 help 883 Use the IA-PC HPET (High Precision Event Timer) to manage 884 time in preference to the PIT and RTC, if a HPET is 885 present. 886 HPET is the next generation timer replacing legacy 8254s. 887 The HPET provides a stable time base on SMP 888 systems, unlike the TSC, but it is more expensive to access, 889 as it is off-chip. The interface used is documented 890 in the HPET spec, revision 1. 891 892 You can safely choose Y here. However, HPET will only be 893 activated if the platform and the BIOS support this feature. 894 Otherwise the 8254 will be used for timing services. 895 896 Choose N to continue using the legacy 8254 timer. 897 898config HPET_EMULATE_RTC 899 def_bool y 900 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 901 902# Mark as expert because too many people got it wrong. 903# The code disables itself when not needed. 904config DMI 905 default y 906 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 907 bool "Enable DMI scanning" if EXPERT 908 help 909 Enabled scanning of DMI to identify machine quirks. Say Y 910 here unless you have verified that your setup is not 911 affected by entries in the DMI blacklist. Required by PNP 912 BIOS code. 913 914config GART_IOMMU 915 bool "Old AMD GART IOMMU support" 916 select DMA_OPS 917 select IOMMU_HELPER 918 select SWIOTLB 919 depends on X86_64 && PCI && AMD_NB 920 help 921 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 922 GART based hardware IOMMUs. 923 924 The GART supports full DMA access for devices with 32-bit access 925 limitations, on systems with more than 3 GB. This is usually needed 926 for USB, sound, many IDE/SATA chipsets and some other devices. 927 928 Newer systems typically have a modern AMD IOMMU, supported via 929 the CONFIG_AMD_IOMMU=y config option. 930 931 In normal configurations this driver is only active when needed: 932 there's more than 3 GB of memory and the system contains a 933 32-bit limited device. 934 935 If unsure, say Y. 936 937config MAXSMP 938 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 939 depends on X86_64 && SMP && DEBUG_KERNEL 940 select CPUMASK_OFFSTACK 941 help 942 Enable maximum number of CPUS and NUMA Nodes for this architecture. 943 If unsure, say N. 944 945# 946# The maximum number of CPUs supported: 947# 948# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 949# and which can be configured interactively in the 950# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 951# 952# The ranges are different on 32-bit and 64-bit kernels, depending on 953# hardware capabilities and scalability features of the kernel. 954# 955# ( If MAXSMP is enabled we just use the highest possible value and disable 956# interactive configuration. ) 957# 958 959config NR_CPUS_RANGE_BEGIN 960 int 961 default NR_CPUS_RANGE_END if MAXSMP 962 default 1 if !SMP 963 default 2 964 965config NR_CPUS_RANGE_END 966 int 967 depends on X86_32 968 default 64 if SMP && X86_BIGSMP 969 default 8 if SMP && !X86_BIGSMP 970 default 1 if !SMP 971 972config NR_CPUS_RANGE_END 973 int 974 depends on X86_64 975 default 8192 if SMP && CPUMASK_OFFSTACK 976 default 512 if SMP && !CPUMASK_OFFSTACK 977 default 1 if !SMP 978 979config NR_CPUS_DEFAULT 980 int 981 depends on X86_32 982 default 32 if X86_BIGSMP 983 default 8 if SMP 984 default 1 if !SMP 985 986config NR_CPUS_DEFAULT 987 int 988 depends on X86_64 989 default 8192 if MAXSMP 990 default 64 if SMP 991 default 1 if !SMP 992 993config NR_CPUS 994 int "Maximum number of CPUs" if SMP && !MAXSMP 995 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 996 default NR_CPUS_DEFAULT 997 help 998 This allows you to specify the maximum number of CPUs which this 999 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1000 supported value is 8192, otherwise the maximum value is 512. The 1001 minimum value which makes sense is 2. 1002 1003 This is purely to save memory: each supported CPU adds about 8KB 1004 to the kernel image. 1005 1006config SCHED_SMT 1007 def_bool y if SMP 1008 1009config SCHED_MC 1010 def_bool y 1011 prompt "Multi-core scheduler support" 1012 depends on SMP 1013 help 1014 Multi-core scheduler support improves the CPU scheduler's decision 1015 making when dealing with multi-core CPU chips at a cost of slightly 1016 increased overhead in some places. If unsure say N here. 1017 1018config SCHED_MC_PRIO 1019 bool "CPU core priorities scheduler support" 1020 depends on SCHED_MC && CPU_SUP_INTEL 1021 select X86_INTEL_PSTATE 1022 select CPU_FREQ 1023 default y 1024 help 1025 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1026 core ordering determined at manufacturing time, which allows 1027 certain cores to reach higher turbo frequencies (when running 1028 single threaded workloads) than others. 1029 1030 Enabling this kernel feature teaches the scheduler about 1031 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1032 scheduler's CPU selection logic accordingly, so that higher 1033 overall system performance can be achieved. 1034 1035 This feature will have no effect on CPUs without this feature. 1036 1037 If unsure say Y here. 1038 1039config UP_LATE_INIT 1040 def_bool y 1041 depends on !SMP && X86_LOCAL_APIC 1042 1043config X86_UP_APIC 1044 bool "Local APIC support on uniprocessors" if !PCI_MSI 1045 default PCI_MSI 1046 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1047 help 1048 A local APIC (Advanced Programmable Interrupt Controller) is an 1049 integrated interrupt controller in the CPU. If you have a single-CPU 1050 system which has a processor with a local APIC, you can say Y here to 1051 enable and use it. If you say Y here even though your machine doesn't 1052 have a local APIC, then the kernel will still run with no slowdown at 1053 all. The local APIC supports CPU-generated self-interrupts (timer, 1054 performance counters), and the NMI watchdog which detects hard 1055 lockups. 1056 1057config X86_UP_IOAPIC 1058 bool "IO-APIC support on uniprocessors" 1059 depends on X86_UP_APIC 1060 help 1061 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1062 SMP-capable replacement for PC-style interrupt controllers. Most 1063 SMP systems and many recent uniprocessor systems have one. 1064 1065 If you have a single-CPU system with an IO-APIC, you can say Y here 1066 to use it. If you say Y here even though your machine doesn't have 1067 an IO-APIC, then the kernel will still run with no slowdown at all. 1068 1069config X86_LOCAL_APIC 1070 def_bool y 1071 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1072 select IRQ_DOMAIN_HIERARCHY 1073 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1074 1075config X86_IO_APIC 1076 def_bool y 1077 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1078 1079config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1080 bool "Reroute for broken boot IRQs" 1081 depends on X86_IO_APIC 1082 help 1083 This option enables a workaround that fixes a source of 1084 spurious interrupts. This is recommended when threaded 1085 interrupt handling is used on systems where the generation of 1086 superfluous "boot interrupts" cannot be disabled. 1087 1088 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1089 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1090 kernel does during interrupt handling). On chipsets where this 1091 boot IRQ generation cannot be disabled, this workaround keeps 1092 the original IRQ line masked so that only the equivalent "boot 1093 IRQ" is delivered to the CPUs. The workaround also tells the 1094 kernel to set up the IRQ handler on the boot IRQ line. In this 1095 way only one interrupt is delivered to the kernel. Otherwise 1096 the spurious second interrupt may cause the kernel to bring 1097 down (vital) interrupt lines. 1098 1099 Only affects "broken" chipsets. Interrupt sharing may be 1100 increased on these systems. 1101 1102config X86_MCE 1103 bool "Machine Check / overheating reporting" 1104 select GENERIC_ALLOCATOR 1105 default y 1106 help 1107 Machine Check support allows the processor to notify the 1108 kernel if it detects a problem (e.g. overheating, data corruption). 1109 The action the kernel takes depends on the severity of the problem, 1110 ranging from warning messages to halting the machine. 1111 1112config X86_MCELOG_LEGACY 1113 bool "Support for deprecated /dev/mcelog character device" 1114 depends on X86_MCE 1115 help 1116 Enable support for /dev/mcelog which is needed by the old mcelog 1117 userspace logging daemon. Consider switching to the new generation 1118 rasdaemon solution. 1119 1120config X86_MCE_INTEL 1121 def_bool y 1122 prompt "Intel MCE features" 1123 depends on X86_MCE && X86_LOCAL_APIC 1124 help 1125 Additional support for intel specific MCE features such as 1126 the thermal monitor. 1127 1128config X86_MCE_AMD 1129 def_bool y 1130 prompt "AMD MCE features" 1131 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1132 help 1133 Additional support for AMD specific MCE features such as 1134 the DRAM Error Threshold. 1135 1136config X86_ANCIENT_MCE 1137 bool "Support for old Pentium 5 / WinChip machine checks" 1138 depends on X86_32 && X86_MCE 1139 help 1140 Include support for machine check handling on old Pentium 5 or WinChip 1141 systems. These typically need to be enabled explicitly on the command 1142 line. 1143 1144config X86_MCE_THRESHOLD 1145 depends on X86_MCE_AMD || X86_MCE_INTEL 1146 def_bool y 1147 1148config X86_MCE_INJECT 1149 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1150 tristate "Machine check injector support" 1151 help 1152 Provide support for injecting machine checks for testing purposes. 1153 If you don't know what a machine check is and you don't do kernel 1154 QA it is safe to say n. 1155 1156source "arch/x86/events/Kconfig" 1157 1158config X86_LEGACY_VM86 1159 bool "Legacy VM86 support" 1160 depends on X86_32 1161 help 1162 This option allows user programs to put the CPU into V8086 1163 mode, which is an 80286-era approximation of 16-bit real mode. 1164 1165 Some very old versions of X and/or vbetool require this option 1166 for user mode setting. Similarly, DOSEMU will use it if 1167 available to accelerate real mode DOS programs. However, any 1168 recent version of DOSEMU, X, or vbetool should be fully 1169 functional even without kernel VM86 support, as they will all 1170 fall back to software emulation. Nevertheless, if you are using 1171 a 16-bit DOS program where 16-bit performance matters, vm86 1172 mode might be faster than emulation and you might want to 1173 enable this option. 1174 1175 Note that any app that works on a 64-bit kernel is unlikely to 1176 need this option, as 64-bit kernels don't, and can't, support 1177 V8086 mode. This option is also unrelated to 16-bit protected 1178 mode and is not needed to run most 16-bit programs under Wine. 1179 1180 Enabling this option increases the complexity of the kernel 1181 and slows down exception handling a tiny bit. 1182 1183 If unsure, say N here. 1184 1185config VM86 1186 bool 1187 default X86_LEGACY_VM86 1188 1189config X86_16BIT 1190 bool "Enable support for 16-bit segments" if EXPERT 1191 default y 1192 depends on MODIFY_LDT_SYSCALL 1193 help 1194 This option is required by programs like Wine to run 16-bit 1195 protected mode legacy code on x86 processors. Disabling 1196 this option saves about 300 bytes on i386, or around 6K text 1197 plus 16K runtime memory on x86-64, 1198 1199config X86_ESPFIX32 1200 def_bool y 1201 depends on X86_16BIT && X86_32 1202 1203config X86_ESPFIX64 1204 def_bool y 1205 depends on X86_16BIT && X86_64 1206 1207config X86_VSYSCALL_EMULATION 1208 bool "Enable vsyscall emulation" if EXPERT 1209 default y 1210 depends on X86_64 1211 help 1212 This enables emulation of the legacy vsyscall page. Disabling 1213 it is roughly equivalent to booting with vsyscall=none, except 1214 that it will also disable the helpful warning if a program 1215 tries to use a vsyscall. With this option set to N, offending 1216 programs will just segfault, citing addresses of the form 1217 0xffffffffff600?00. 1218 1219 This option is required by many programs built before 2013, and 1220 care should be used even with newer programs if set to N. 1221 1222 Disabling this option saves about 7K of kernel size and 1223 possibly 4K of additional runtime pagetable memory. 1224 1225config X86_IOPL_IOPERM 1226 bool "IOPERM and IOPL Emulation" 1227 default y 1228 help 1229 This enables the ioperm() and iopl() syscalls which are necessary 1230 for legacy applications. 1231 1232 Legacy IOPL support is an overbroad mechanism which allows user 1233 space aside of accessing all 65536 I/O ports also to disable 1234 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1235 capabilities and permission from potentially active security 1236 modules. 1237 1238 The emulation restricts the functionality of the syscall to 1239 only allowing the full range I/O port access, but prevents the 1240 ability to disable interrupts from user space which would be 1241 granted if the hardware IOPL mechanism would be used. 1242 1243config TOSHIBA 1244 tristate "Toshiba Laptop support" 1245 depends on X86_32 1246 help 1247 This adds a driver to safely access the System Management Mode of 1248 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1249 not work on models with a Phoenix BIOS. The System Management Mode 1250 is used to set the BIOS and power saving options on Toshiba portables. 1251 1252 For information on utilities to make use of this driver see the 1253 Toshiba Linux utilities web site at: 1254 <http://www.buzzard.org.uk/toshiba/>. 1255 1256 Say Y if you intend to run this kernel on a Toshiba portable. 1257 Say N otherwise. 1258 1259config I8K 1260 tristate "Dell i8k legacy laptop support" 1261 select HWMON 1262 select SENSORS_DELL_SMM 1263 help 1264 This option enables legacy /proc/i8k userspace interface in hwmon 1265 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1266 temperature and allows controlling fan speeds of Dell laptops via 1267 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1268 it reports also power and hotkey status. For fan speed control is 1269 needed userspace package i8kutils. 1270 1271 Say Y if you intend to run this kernel on old Dell laptops or want to 1272 use userspace package i8kutils. 1273 Say N otherwise. 1274 1275config X86_REBOOTFIXUPS 1276 bool "Enable X86 board specific fixups for reboot" 1277 depends on X86_32 1278 help 1279 This enables chipset and/or board specific fixups to be done 1280 in order to get reboot to work correctly. This is only needed on 1281 some combinations of hardware and BIOS. The symptom, for which 1282 this config is intended, is when reboot ends with a stalled/hung 1283 system. 1284 1285 Currently, the only fixup is for the Geode machines using 1286 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1287 1288 Say Y if you want to enable the fixup. Currently, it's safe to 1289 enable this option even if you don't need it. 1290 Say N otherwise. 1291 1292config MICROCODE 1293 bool "CPU microcode loading support" 1294 default y 1295 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1296 help 1297 If you say Y here, you will be able to update the microcode on 1298 Intel and AMD processors. The Intel support is for the IA32 family, 1299 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1300 AMD support is for families 0x10 and later. You will obviously need 1301 the actual microcode binary data itself which is not shipped with 1302 the Linux kernel. 1303 1304 The preferred method to load microcode from a detached initrd is described 1305 in Documentation/x86/microcode.rst. For that you need to enable 1306 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1307 initrd for microcode blobs. 1308 1309 In addition, you can build the microcode into the kernel. For that you 1310 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1311 config option. 1312 1313config MICROCODE_INTEL 1314 bool "Intel microcode loading support" 1315 depends on MICROCODE 1316 default MICROCODE 1317 help 1318 This options enables microcode patch loading support for Intel 1319 processors. 1320 1321 For the current Intel microcode data package go to 1322 <https://downloadcenter.intel.com> and search for 1323 'Linux Processor Microcode Data File'. 1324 1325config MICROCODE_AMD 1326 bool "AMD microcode loading support" 1327 depends on MICROCODE 1328 help 1329 If you select this option, microcode patch loading support for AMD 1330 processors will be enabled. 1331 1332config MICROCODE_OLD_INTERFACE 1333 bool "Ancient loading interface (DEPRECATED)" 1334 default n 1335 depends on MICROCODE 1336 help 1337 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1338 which was used by userspace tools like iucode_tool and microcode.ctl. 1339 It is inadequate because it runs too late to be able to properly 1340 load microcode on a machine and it needs special tools. Instead, you 1341 should've switched to the early loading method with the initrd or 1342 builtin microcode by now: Documentation/x86/microcode.rst 1343 1344config X86_MSR 1345 tristate "/dev/cpu/*/msr - Model-specific register support" 1346 help 1347 This device gives privileged processes access to the x86 1348 Model-Specific Registers (MSRs). It is a character device with 1349 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1350 MSR accesses are directed to a specific CPU on multi-processor 1351 systems. 1352 1353config X86_CPUID 1354 tristate "/dev/cpu/*/cpuid - CPU information support" 1355 help 1356 This device gives processes access to the x86 CPUID instruction to 1357 be executed on a specific processor. It is a character device 1358 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1359 /dev/cpu/31/cpuid. 1360 1361choice 1362 prompt "High Memory Support" 1363 default HIGHMEM4G 1364 depends on X86_32 1365 1366config NOHIGHMEM 1367 bool "off" 1368 help 1369 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1370 However, the address space of 32-bit x86 processors is only 4 1371 Gigabytes large. That means that, if you have a large amount of 1372 physical memory, not all of it can be "permanently mapped" by the 1373 kernel. The physical memory that's not permanently mapped is called 1374 "high memory". 1375 1376 If you are compiling a kernel which will never run on a machine with 1377 more than 1 Gigabyte total physical RAM, answer "off" here (default 1378 choice and suitable for most users). This will result in a "3GB/1GB" 1379 split: 3GB are mapped so that each process sees a 3GB virtual memory 1380 space and the remaining part of the 4GB virtual memory space is used 1381 by the kernel to permanently map as much physical memory as 1382 possible. 1383 1384 If the machine has between 1 and 4 Gigabytes physical RAM, then 1385 answer "4GB" here. 1386 1387 If more than 4 Gigabytes is used then answer "64GB" here. This 1388 selection turns Intel PAE (Physical Address Extension) mode on. 1389 PAE implements 3-level paging on IA32 processors. PAE is fully 1390 supported by Linux, PAE mode is implemented on all recent Intel 1391 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1392 then the kernel will not boot on CPUs that don't support PAE! 1393 1394 The actual amount of total physical memory will either be 1395 auto detected or can be forced by using a kernel command line option 1396 such as "mem=256M". (Try "man bootparam" or see the documentation of 1397 your boot loader (lilo or loadlin) about how to pass options to the 1398 kernel at boot time.) 1399 1400 If unsure, say "off". 1401 1402config HIGHMEM4G 1403 bool "4GB" 1404 help 1405 Select this if you have a 32-bit processor and between 1 and 4 1406 gigabytes of physical RAM. 1407 1408config HIGHMEM64G 1409 bool "64GB" 1410 depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1411 select X86_PAE 1412 help 1413 Select this if you have a 32-bit processor and more than 4 1414 gigabytes of physical RAM. 1415 1416endchoice 1417 1418choice 1419 prompt "Memory split" if EXPERT 1420 default VMSPLIT_3G 1421 depends on X86_32 1422 help 1423 Select the desired split between kernel and user memory. 1424 1425 If the address range available to the kernel is less than the 1426 physical memory installed, the remaining memory will be available 1427 as "high memory". Accessing high memory is a little more costly 1428 than low memory, as it needs to be mapped into the kernel first. 1429 Note that increasing the kernel address space limits the range 1430 available to user programs, making the address space there 1431 tighter. Selecting anything other than the default 3G/1G split 1432 will also likely make your kernel incompatible with binary-only 1433 kernel modules. 1434 1435 If you are not absolutely sure what you are doing, leave this 1436 option alone! 1437 1438 config VMSPLIT_3G 1439 bool "3G/1G user/kernel split" 1440 config VMSPLIT_3G_OPT 1441 depends on !X86_PAE 1442 bool "3G/1G user/kernel split (for full 1G low memory)" 1443 config VMSPLIT_2G 1444 bool "2G/2G user/kernel split" 1445 config VMSPLIT_2G_OPT 1446 depends on !X86_PAE 1447 bool "2G/2G user/kernel split (for full 2G low memory)" 1448 config VMSPLIT_1G 1449 bool "1G/3G user/kernel split" 1450endchoice 1451 1452config PAGE_OFFSET 1453 hex 1454 default 0xB0000000 if VMSPLIT_3G_OPT 1455 default 0x80000000 if VMSPLIT_2G 1456 default 0x78000000 if VMSPLIT_2G_OPT 1457 default 0x40000000 if VMSPLIT_1G 1458 default 0xC0000000 1459 depends on X86_32 1460 1461config HIGHMEM 1462 def_bool y 1463 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1464 1465config X86_PAE 1466 bool "PAE (Physical Address Extension) Support" 1467 depends on X86_32 && !HIGHMEM4G 1468 select PHYS_ADDR_T_64BIT 1469 select SWIOTLB 1470 help 1471 PAE is required for NX support, and furthermore enables 1472 larger swapspace support for non-overcommit purposes. It 1473 has the cost of more pagetable lookup overhead, and also 1474 consumes more pagetable space per process. 1475 1476config X86_5LEVEL 1477 bool "Enable 5-level page tables support" 1478 default y 1479 select DYNAMIC_MEMORY_LAYOUT 1480 select SPARSEMEM_VMEMMAP 1481 depends on X86_64 1482 help 1483 5-level paging enables access to larger address space: 1484 upto 128 PiB of virtual address space and 4 PiB of 1485 physical address space. 1486 1487 It will be supported by future Intel CPUs. 1488 1489 A kernel with the option enabled can be booted on machines that 1490 support 4- or 5-level paging. 1491 1492 See Documentation/x86/x86_64/5level-paging.rst for more 1493 information. 1494 1495 Say N if unsure. 1496 1497config X86_DIRECT_GBPAGES 1498 def_bool y 1499 depends on X86_64 1500 help 1501 Certain kernel features effectively disable kernel 1502 linear 1 GB mappings (even if the CPU otherwise 1503 supports them), so don't confuse the user by printing 1504 that we have them enabled. 1505 1506config X86_CPA_STATISTICS 1507 bool "Enable statistic for Change Page Attribute" 1508 depends on DEBUG_FS 1509 help 1510 Expose statistics about the Change Page Attribute mechanism, which 1511 helps to determine the effectiveness of preserving large and huge 1512 page mappings when mapping protections are changed. 1513 1514config AMD_MEM_ENCRYPT 1515 bool "AMD Secure Memory Encryption (SME) support" 1516 depends on X86_64 && CPU_SUP_AMD 1517 select DMA_COHERENT_POOL 1518 select DYNAMIC_PHYSICAL_MASK 1519 select ARCH_USE_MEMREMAP_PROT 1520 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1521 select INSTRUCTION_DECODER 1522 select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS 1523 help 1524 Say yes to enable support for the encryption of system memory. 1525 This requires an AMD processor that supports Secure Memory 1526 Encryption (SME). 1527 1528config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1529 bool "Activate AMD Secure Memory Encryption (SME) by default" 1530 default y 1531 depends on AMD_MEM_ENCRYPT 1532 help 1533 Say yes to have system memory encrypted by default if running on 1534 an AMD processor that supports Secure Memory Encryption (SME). 1535 1536 If set to Y, then the encryption of system memory can be 1537 deactivated with the mem_encrypt=off command line option. 1538 1539 If set to N, then the encryption of system memory can be 1540 activated with the mem_encrypt=on command line option. 1541 1542# Common NUMA Features 1543config NUMA 1544 bool "NUMA Memory Allocation and Scheduler Support" 1545 depends on SMP 1546 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1547 default y if X86_BIGSMP 1548 help 1549 Enable NUMA (Non-Uniform Memory Access) support. 1550 1551 The kernel will try to allocate memory used by a CPU on the 1552 local memory controller of the CPU and add some more 1553 NUMA awareness to the kernel. 1554 1555 For 64-bit this is recommended if the system is Intel Core i7 1556 (or later), AMD Opteron, or EM64T NUMA. 1557 1558 For 32-bit this is only needed if you boot a 32-bit 1559 kernel on a 64-bit NUMA platform. 1560 1561 Otherwise, you should say N. 1562 1563config AMD_NUMA 1564 def_bool y 1565 prompt "Old style AMD Opteron NUMA detection" 1566 depends on X86_64 && NUMA && PCI 1567 help 1568 Enable AMD NUMA node topology detection. You should say Y here if 1569 you have a multi processor AMD system. This uses an old method to 1570 read the NUMA configuration directly from the builtin Northbridge 1571 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1572 which also takes priority if both are compiled in. 1573 1574config X86_64_ACPI_NUMA 1575 def_bool y 1576 prompt "ACPI NUMA detection" 1577 depends on X86_64 && NUMA && ACPI && PCI 1578 select ACPI_NUMA 1579 help 1580 Enable ACPI SRAT based node topology detection. 1581 1582config NUMA_EMU 1583 bool "NUMA emulation" 1584 depends on NUMA 1585 help 1586 Enable NUMA emulation. A flat machine will be split 1587 into virtual nodes when booted with "numa=fake=N", where N is the 1588 number of nodes. This is only useful for debugging. 1589 1590config NODES_SHIFT 1591 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1592 range 1 10 1593 default "10" if MAXSMP 1594 default "6" if X86_64 1595 default "3" 1596 depends on NEED_MULTIPLE_NODES 1597 help 1598 Specify the maximum number of NUMA Nodes available on the target 1599 system. Increases memory reserved to accommodate various tables. 1600 1601config ARCH_FLATMEM_ENABLE 1602 def_bool y 1603 depends on X86_32 && !NUMA 1604 1605config ARCH_SPARSEMEM_ENABLE 1606 def_bool y 1607 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1608 select SPARSEMEM_STATIC if X86_32 1609 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1610 1611config ARCH_SPARSEMEM_DEFAULT 1612 def_bool X86_64 || (NUMA && X86_32) 1613 1614config ARCH_SELECT_MEMORY_MODEL 1615 def_bool y 1616 depends on ARCH_SPARSEMEM_ENABLE 1617 1618config ARCH_MEMORY_PROBE 1619 bool "Enable sysfs memory/probe interface" 1620 depends on X86_64 && MEMORY_HOTPLUG 1621 help 1622 This option enables a sysfs memory/probe interface for testing. 1623 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1624 If you are unsure how to answer this question, answer N. 1625 1626config ARCH_PROC_KCORE_TEXT 1627 def_bool y 1628 depends on X86_64 && PROC_KCORE 1629 1630config ILLEGAL_POINTER_VALUE 1631 hex 1632 default 0 if X86_32 1633 default 0xdead000000000000 if X86_64 1634 1635config X86_PMEM_LEGACY_DEVICE 1636 bool 1637 1638config X86_PMEM_LEGACY 1639 tristate "Support non-standard NVDIMMs and ADR protected memory" 1640 depends on PHYS_ADDR_T_64BIT 1641 depends on BLK_DEV 1642 select X86_PMEM_LEGACY_DEVICE 1643 select NUMA_KEEP_MEMINFO if NUMA 1644 select LIBNVDIMM 1645 help 1646 Treat memory marked using the non-standard e820 type of 12 as used 1647 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1648 The kernel will offer these regions to the 'pmem' driver so 1649 they can be used for persistent storage. 1650 1651 Say Y if unsure. 1652 1653config HIGHPTE 1654 bool "Allocate 3rd-level pagetables from highmem" 1655 depends on HIGHMEM 1656 help 1657 The VM uses one page table entry for each page of physical memory. 1658 For systems with a lot of RAM, this can be wasteful of precious 1659 low memory. Setting this option will put user-space page table 1660 entries in high memory. 1661 1662config X86_CHECK_BIOS_CORRUPTION 1663 bool "Check for low memory corruption" 1664 help 1665 Periodically check for memory corruption in low memory, which 1666 is suspected to be caused by BIOS. Even when enabled in the 1667 configuration, it is disabled at runtime. Enable it by 1668 setting "memory_corruption_check=1" on the kernel command 1669 line. By default it scans the low 64k of memory every 60 1670 seconds; see the memory_corruption_check_size and 1671 memory_corruption_check_period parameters in 1672 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1673 1674 When enabled with the default parameters, this option has 1675 almost no overhead, as it reserves a relatively small amount 1676 of memory and scans it infrequently. It both detects corruption 1677 and prevents it from affecting the running system. 1678 1679 It is, however, intended as a diagnostic tool; if repeatable 1680 BIOS-originated corruption always affects the same memory, 1681 you can use memmap= to prevent the kernel from using that 1682 memory. 1683 1684config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1685 bool "Set the default setting of memory_corruption_check" 1686 depends on X86_CHECK_BIOS_CORRUPTION 1687 default y 1688 help 1689 Set whether the default state of memory_corruption_check is 1690 on or off. 1691 1692config X86_RESERVE_LOW 1693 int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1694 default 64 1695 range 4 640 1696 help 1697 Specify the amount of low memory to reserve for the BIOS. 1698 1699 The first page contains BIOS data structures that the kernel 1700 must not use, so that page must always be reserved. 1701 1702 By default we reserve the first 64K of physical RAM, as a 1703 number of BIOSes are known to corrupt that memory range 1704 during events such as suspend/resume or monitor cable 1705 insertion, so it must not be used by the kernel. 1706 1707 You can set this to 4 if you are absolutely sure that you 1708 trust the BIOS to get all its memory reservations and usages 1709 right. If you know your BIOS have problems beyond the 1710 default 64K area, you can set this to 640 to avoid using the 1711 entire low memory range. 1712 1713 If you have doubts about the BIOS (e.g. suspend/resume does 1714 not work or there's kernel crashes after certain hardware 1715 hotplug events) then you might want to enable 1716 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1717 typical corruption patterns. 1718 1719 Leave this to the default value of 64 if you are unsure. 1720 1721config MATH_EMULATION 1722 bool 1723 depends on MODIFY_LDT_SYSCALL 1724 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1725 help 1726 Linux can emulate a math coprocessor (used for floating point 1727 operations) if you don't have one. 486DX and Pentium processors have 1728 a math coprocessor built in, 486SX and 386 do not, unless you added 1729 a 487DX or 387, respectively. (The messages during boot time can 1730 give you some hints here ["man dmesg"].) Everyone needs either a 1731 coprocessor or this emulation. 1732 1733 If you don't have a math coprocessor, you need to say Y here; if you 1734 say Y here even though you have a coprocessor, the coprocessor will 1735 be used nevertheless. (This behavior can be changed with the kernel 1736 command line option "no387", which comes handy if your coprocessor 1737 is broken. Try "man bootparam" or see the documentation of your boot 1738 loader (lilo or loadlin) about how to pass options to the kernel at 1739 boot time.) This means that it is a good idea to say Y here if you 1740 intend to use this kernel on different machines. 1741 1742 More information about the internals of the Linux math coprocessor 1743 emulation can be found in <file:arch/x86/math-emu/README>. 1744 1745 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1746 kernel, it won't hurt. 1747 1748config MTRR 1749 def_bool y 1750 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1751 help 1752 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1753 the Memory Type Range Registers (MTRRs) may be used to control 1754 processor access to memory ranges. This is most useful if you have 1755 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1756 allows bus write transfers to be combined into a larger transfer 1757 before bursting over the PCI/AGP bus. This can increase performance 1758 of image write operations 2.5 times or more. Saying Y here creates a 1759 /proc/mtrr file which may be used to manipulate your processor's 1760 MTRRs. Typically the X server should use this. 1761 1762 This code has a reasonably generic interface so that similar 1763 control registers on other processors can be easily supported 1764 as well: 1765 1766 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1767 Registers (ARRs) which provide a similar functionality to MTRRs. For 1768 these, the ARRs are used to emulate the MTRRs. 1769 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1770 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1771 write-combining. All of these processors are supported by this code 1772 and it makes sense to say Y here if you have one of them. 1773 1774 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1775 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1776 can lead to all sorts of problems, so it's good to say Y here. 1777 1778 You can safely say Y even if your machine doesn't have MTRRs, you'll 1779 just add about 9 KB to your kernel. 1780 1781 See <file:Documentation/x86/mtrr.rst> for more information. 1782 1783config MTRR_SANITIZER 1784 def_bool y 1785 prompt "MTRR cleanup support" 1786 depends on MTRR 1787 help 1788 Convert MTRR layout from continuous to discrete, so X drivers can 1789 add writeback entries. 1790 1791 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1792 The largest mtrr entry size for a continuous block can be set with 1793 mtrr_chunk_size. 1794 1795 If unsure, say Y. 1796 1797config MTRR_SANITIZER_ENABLE_DEFAULT 1798 int "MTRR cleanup enable value (0-1)" 1799 range 0 1 1800 default "0" 1801 depends on MTRR_SANITIZER 1802 help 1803 Enable mtrr cleanup default value 1804 1805config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1806 int "MTRR cleanup spare reg num (0-7)" 1807 range 0 7 1808 default "1" 1809 depends on MTRR_SANITIZER 1810 help 1811 mtrr cleanup spare entries default, it can be changed via 1812 mtrr_spare_reg_nr=N on the kernel command line. 1813 1814config X86_PAT 1815 def_bool y 1816 prompt "x86 PAT support" if EXPERT 1817 depends on MTRR 1818 help 1819 Use PAT attributes to setup page level cache control. 1820 1821 PATs are the modern equivalents of MTRRs and are much more 1822 flexible than MTRRs. 1823 1824 Say N here if you see bootup problems (boot crash, boot hang, 1825 spontaneous reboots) or a non-working video driver. 1826 1827 If unsure, say Y. 1828 1829config ARCH_USES_PG_UNCACHED 1830 def_bool y 1831 depends on X86_PAT 1832 1833config ARCH_RANDOM 1834 def_bool y 1835 prompt "x86 architectural random number generator" if EXPERT 1836 help 1837 Enable the x86 architectural RDRAND instruction 1838 (Intel Bull Mountain technology) to generate random numbers. 1839 If supported, this is a high bandwidth, cryptographically 1840 secure hardware random number generator. 1841 1842config X86_SMAP 1843 def_bool y 1844 prompt "Supervisor Mode Access Prevention" if EXPERT 1845 help 1846 Supervisor Mode Access Prevention (SMAP) is a security 1847 feature in newer Intel processors. There is a small 1848 performance cost if this enabled and turned on; there is 1849 also a small increase in the kernel size if this is enabled. 1850 1851 If unsure, say Y. 1852 1853config X86_UMIP 1854 def_bool y 1855 prompt "User Mode Instruction Prevention" if EXPERT 1856 help 1857 User Mode Instruction Prevention (UMIP) is a security feature in 1858 some x86 processors. If enabled, a general protection fault is 1859 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1860 executed in user mode. These instructions unnecessarily expose 1861 information about the hardware state. 1862 1863 The vast majority of applications do not use these instructions. 1864 For the very few that do, software emulation is provided in 1865 specific cases in protected and virtual-8086 modes. Emulated 1866 results are dummy. 1867 1868config X86_INTEL_MEMORY_PROTECTION_KEYS 1869 prompt "Memory Protection Keys" 1870 def_bool y 1871 # Note: only available in 64-bit mode 1872 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1873 select ARCH_USES_HIGH_VMA_FLAGS 1874 select ARCH_HAS_PKEYS 1875 help 1876 Memory Protection Keys provides a mechanism for enforcing 1877 page-based protections, but without requiring modification of the 1878 page tables when an application changes protection domains. 1879 1880 For details, see Documentation/core-api/protection-keys.rst 1881 1882 If unsure, say y. 1883 1884choice 1885 prompt "TSX enable mode" 1886 depends on CPU_SUP_INTEL 1887 default X86_INTEL_TSX_MODE_OFF 1888 help 1889 Intel's TSX (Transactional Synchronization Extensions) feature 1890 allows to optimize locking protocols through lock elision which 1891 can lead to a noticeable performance boost. 1892 1893 On the other hand it has been shown that TSX can be exploited 1894 to form side channel attacks (e.g. TAA) and chances are there 1895 will be more of those attacks discovered in the future. 1896 1897 Therefore TSX is not enabled by default (aka tsx=off). An admin 1898 might override this decision by tsx=on the command line parameter. 1899 Even with TSX enabled, the kernel will attempt to enable the best 1900 possible TAA mitigation setting depending on the microcode available 1901 for the particular machine. 1902 1903 This option allows to set the default tsx mode between tsx=on, =off 1904 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1905 details. 1906 1907 Say off if not sure, auto if TSX is in use but it should be used on safe 1908 platforms or on if TSX is in use and the security aspect of tsx is not 1909 relevant. 1910 1911config X86_INTEL_TSX_MODE_OFF 1912 bool "off" 1913 help 1914 TSX is disabled if possible - equals to tsx=off command line parameter. 1915 1916config X86_INTEL_TSX_MODE_ON 1917 bool "on" 1918 help 1919 TSX is always enabled on TSX capable HW - equals the tsx=on command 1920 line parameter. 1921 1922config X86_INTEL_TSX_MODE_AUTO 1923 bool "auto" 1924 help 1925 TSX is enabled on TSX capable HW that is believed to be safe against 1926 side channel attacks- equals the tsx=auto command line parameter. 1927endchoice 1928 1929config X86_SGX 1930 bool "Software Guard eXtensions (SGX)" 1931 depends on X86_64 && CPU_SUP_INTEL 1932 depends on CRYPTO=y 1933 depends on CRYPTO_SHA256=y 1934 select SRCU 1935 select MMU_NOTIFIER 1936 select NUMA_KEEP_MEMINFO if NUMA 1937 help 1938 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1939 that can be used by applications to set aside private regions of code 1940 and data, referred to as enclaves. An enclave's private memory can 1941 only be accessed by code running within the enclave. Accesses from 1942 outside the enclave, including other enclaves, are disallowed by 1943 hardware. 1944 1945 If unsure, say N. 1946 1947config EFI 1948 bool "EFI runtime service support" 1949 depends on ACPI 1950 select UCS2_STRING 1951 select EFI_RUNTIME_WRAPPERS 1952 help 1953 This enables the kernel to use EFI runtime services that are 1954 available (such as the EFI variable services). 1955 1956 This option is only useful on systems that have EFI firmware. 1957 In addition, you should use the latest ELILO loader available 1958 at <http://elilo.sourceforge.net> in order to take advantage 1959 of EFI runtime services. However, even with this option, the 1960 resultant kernel should continue to boot on existing non-EFI 1961 platforms. 1962 1963config EFI_STUB 1964 bool "EFI stub support" 1965 depends on EFI && !X86_USE_3DNOW 1966 depends on $(cc-option,-mabi=ms) || X86_32 1967 select RELOCATABLE 1968 help 1969 This kernel feature allows a bzImage to be loaded directly 1970 by EFI firmware without the use of a bootloader. 1971 1972 See Documentation/admin-guide/efi-stub.rst for more information. 1973 1974config EFI_MIXED 1975 bool "EFI mixed-mode support" 1976 depends on EFI_STUB && X86_64 1977 help 1978 Enabling this feature allows a 64-bit kernel to be booted 1979 on a 32-bit firmware, provided that your CPU supports 64-bit 1980 mode. 1981 1982 Note that it is not possible to boot a mixed-mode enabled 1983 kernel via the EFI boot stub - a bootloader that supports 1984 the EFI handover protocol must be used. 1985 1986 If unsure, say N. 1987 1988source "kernel/Kconfig.hz" 1989 1990config KEXEC 1991 bool "kexec system call" 1992 select KEXEC_CORE 1993 help 1994 kexec is a system call that implements the ability to shutdown your 1995 current kernel, and to start another kernel. It is like a reboot 1996 but it is independent of the system firmware. And like a reboot 1997 you can start any kernel with it, not just Linux. 1998 1999 The name comes from the similarity to the exec system call. 2000 2001 It is an ongoing process to be certain the hardware in a machine 2002 is properly shutdown, so do not be surprised if this code does not 2003 initially work for you. As of this writing the exact hardware 2004 interface is strongly in flux, so no good recommendation can be 2005 made. 2006 2007config KEXEC_FILE 2008 bool "kexec file based system call" 2009 select KEXEC_CORE 2010 select BUILD_BIN2C 2011 depends on X86_64 2012 depends on CRYPTO=y 2013 depends on CRYPTO_SHA256=y 2014 help 2015 This is new version of kexec system call. This system call is 2016 file based and takes file descriptors as system call argument 2017 for kernel and initramfs as opposed to list of segments as 2018 accepted by previous system call. 2019 2020config ARCH_HAS_KEXEC_PURGATORY 2021 def_bool KEXEC_FILE 2022 2023config KEXEC_SIG 2024 bool "Verify kernel signature during kexec_file_load() syscall" 2025 depends on KEXEC_FILE 2026 help 2027 2028 This option makes the kexec_file_load() syscall check for a valid 2029 signature of the kernel image. The image can still be loaded without 2030 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2031 there's a signature that we can check, then it must be valid. 2032 2033 In addition to this option, you need to enable signature 2034 verification for the corresponding kernel image type being 2035 loaded in order for this to work. 2036 2037config KEXEC_SIG_FORCE 2038 bool "Require a valid signature in kexec_file_load() syscall" 2039 depends on KEXEC_SIG 2040 help 2041 This option makes kernel signature verification mandatory for 2042 the kexec_file_load() syscall. 2043 2044config KEXEC_BZIMAGE_VERIFY_SIG 2045 bool "Enable bzImage signature verification support" 2046 depends on KEXEC_SIG 2047 depends on SIGNED_PE_FILE_VERIFICATION 2048 select SYSTEM_TRUSTED_KEYRING 2049 help 2050 Enable bzImage signature verification support. 2051 2052config CRASH_DUMP 2053 bool "kernel crash dumps" 2054 depends on X86_64 || (X86_32 && HIGHMEM) 2055 help 2056 Generate crash dump after being started by kexec. 2057 This should be normally only set in special crash dump kernels 2058 which are loaded in the main kernel with kexec-tools into 2059 a specially reserved region and then later executed after 2060 a crash by kdump/kexec. The crash dump kernel must be compiled 2061 to a memory address not used by the main kernel or BIOS using 2062 PHYSICAL_START, or it must be built as a relocatable image 2063 (CONFIG_RELOCATABLE=y). 2064 For more details see Documentation/admin-guide/kdump/kdump.rst 2065 2066config KEXEC_JUMP 2067 bool "kexec jump" 2068 depends on KEXEC && HIBERNATION 2069 help 2070 Jump between original kernel and kexeced kernel and invoke 2071 code in physical address mode via KEXEC 2072 2073config PHYSICAL_START 2074 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2075 default "0x1000000" 2076 help 2077 This gives the physical address where the kernel is loaded. 2078 2079 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2080 bzImage will decompress itself to above physical address and 2081 run from there. Otherwise, bzImage will run from the address where 2082 it has been loaded by the boot loader and will ignore above physical 2083 address. 2084 2085 In normal kdump cases one does not have to set/change this option 2086 as now bzImage can be compiled as a completely relocatable image 2087 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2088 address. This option is mainly useful for the folks who don't want 2089 to use a bzImage for capturing the crash dump and want to use a 2090 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2091 to be specifically compiled to run from a specific memory area 2092 (normally a reserved region) and this option comes handy. 2093 2094 So if you are using bzImage for capturing the crash dump, 2095 leave the value here unchanged to 0x1000000 and set 2096 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2097 for capturing the crash dump change this value to start of 2098 the reserved region. In other words, it can be set based on 2099 the "X" value as specified in the "crashkernel=YM@XM" 2100 command line boot parameter passed to the panic-ed 2101 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2102 for more details about crash dumps. 2103 2104 Usage of bzImage for capturing the crash dump is recommended as 2105 one does not have to build two kernels. Same kernel can be used 2106 as production kernel and capture kernel. Above option should have 2107 gone away after relocatable bzImage support is introduced. But it 2108 is present because there are users out there who continue to use 2109 vmlinux for dump capture. This option should go away down the 2110 line. 2111 2112 Don't change this unless you know what you are doing. 2113 2114config RELOCATABLE 2115 bool "Build a relocatable kernel" 2116 default y 2117 help 2118 This builds a kernel image that retains relocation information 2119 so it can be loaded someplace besides the default 1MB. 2120 The relocations tend to make the kernel binary about 10% larger, 2121 but are discarded at runtime. 2122 2123 One use is for the kexec on panic case where the recovery kernel 2124 must live at a different physical address than the primary 2125 kernel. 2126 2127 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2128 it has been loaded at and the compile time physical address 2129 (CONFIG_PHYSICAL_START) is used as the minimum location. 2130 2131config RANDOMIZE_BASE 2132 bool "Randomize the address of the kernel image (KASLR)" 2133 depends on RELOCATABLE 2134 default y 2135 help 2136 In support of Kernel Address Space Layout Randomization (KASLR), 2137 this randomizes the physical address at which the kernel image 2138 is decompressed and the virtual address where the kernel 2139 image is mapped, as a security feature that deters exploit 2140 attempts relying on knowledge of the location of kernel 2141 code internals. 2142 2143 On 64-bit, the kernel physical and virtual addresses are 2144 randomized separately. The physical address will be anywhere 2145 between 16MB and the top of physical memory (up to 64TB). The 2146 virtual address will be randomized from 16MB up to 1GB (9 bits 2147 of entropy). Note that this also reduces the memory space 2148 available to kernel modules from 1.5GB to 1GB. 2149 2150 On 32-bit, the kernel physical and virtual addresses are 2151 randomized together. They will be randomized from 16MB up to 2152 512MB (8 bits of entropy). 2153 2154 Entropy is generated using the RDRAND instruction if it is 2155 supported. If RDTSC is supported, its value is mixed into 2156 the entropy pool as well. If neither RDRAND nor RDTSC are 2157 supported, then entropy is read from the i8254 timer. The 2158 usable entropy is limited by the kernel being built using 2159 2GB addressing, and that PHYSICAL_ALIGN must be at a 2160 minimum of 2MB. As a result, only 10 bits of entropy are 2161 theoretically possible, but the implementations are further 2162 limited due to memory layouts. 2163 2164 If unsure, say Y. 2165 2166# Relocation on x86 needs some additional build support 2167config X86_NEED_RELOCS 2168 def_bool y 2169 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2170 2171config PHYSICAL_ALIGN 2172 hex "Alignment value to which kernel should be aligned" 2173 default "0x200000" 2174 range 0x2000 0x1000000 if X86_32 2175 range 0x200000 0x1000000 if X86_64 2176 help 2177 This value puts the alignment restrictions on physical address 2178 where kernel is loaded and run from. Kernel is compiled for an 2179 address which meets above alignment restriction. 2180 2181 If bootloader loads the kernel at a non-aligned address and 2182 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2183 address aligned to above value and run from there. 2184 2185 If bootloader loads the kernel at a non-aligned address and 2186 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2187 load address and decompress itself to the address it has been 2188 compiled for and run from there. The address for which kernel is 2189 compiled already meets above alignment restrictions. Hence the 2190 end result is that kernel runs from a physical address meeting 2191 above alignment restrictions. 2192 2193 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2194 this value must be a multiple of 0x200000. 2195 2196 Don't change this unless you know what you are doing. 2197 2198config DYNAMIC_MEMORY_LAYOUT 2199 bool 2200 help 2201 This option makes base addresses of vmalloc and vmemmap as well as 2202 __PAGE_OFFSET movable during boot. 2203 2204config RANDOMIZE_MEMORY 2205 bool "Randomize the kernel memory sections" 2206 depends on X86_64 2207 depends on RANDOMIZE_BASE 2208 select DYNAMIC_MEMORY_LAYOUT 2209 default RANDOMIZE_BASE 2210 help 2211 Randomizes the base virtual address of kernel memory sections 2212 (physical memory mapping, vmalloc & vmemmap). This security feature 2213 makes exploits relying on predictable memory locations less reliable. 2214 2215 The order of allocations remains unchanged. Entropy is generated in 2216 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2217 configuration have in average 30,000 different possible virtual 2218 addresses for each memory section. 2219 2220 If unsure, say Y. 2221 2222config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2223 hex "Physical memory mapping padding" if EXPERT 2224 depends on RANDOMIZE_MEMORY 2225 default "0xa" if MEMORY_HOTPLUG 2226 default "0x0" 2227 range 0x1 0x40 if MEMORY_HOTPLUG 2228 range 0x0 0x40 2229 help 2230 Define the padding in terabytes added to the existing physical 2231 memory size during kernel memory randomization. It is useful 2232 for memory hotplug support but reduces the entropy available for 2233 address randomization. 2234 2235 If unsure, leave at the default value. 2236 2237config HOTPLUG_CPU 2238 def_bool y 2239 depends on SMP 2240 2241config BOOTPARAM_HOTPLUG_CPU0 2242 bool "Set default setting of cpu0_hotpluggable" 2243 depends on HOTPLUG_CPU 2244 help 2245 Set whether default state of cpu0_hotpluggable is on or off. 2246 2247 Say Y here to enable CPU0 hotplug by default. If this switch 2248 is turned on, there is no need to give cpu0_hotplug kernel 2249 parameter and the CPU0 hotplug feature is enabled by default. 2250 2251 Please note: there are two known CPU0 dependencies if you want 2252 to enable the CPU0 hotplug feature either by this switch or by 2253 cpu0_hotplug kernel parameter. 2254 2255 First, resume from hibernate or suspend always starts from CPU0. 2256 So hibernate and suspend are prevented if CPU0 is offline. 2257 2258 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2259 offline if any interrupt can not migrate out of CPU0. There may 2260 be other CPU0 dependencies. 2261 2262 Please make sure the dependencies are under your control before 2263 you enable this feature. 2264 2265 Say N if you don't want to enable CPU0 hotplug feature by default. 2266 You still can enable the CPU0 hotplug feature at boot by kernel 2267 parameter cpu0_hotplug. 2268 2269config DEBUG_HOTPLUG_CPU0 2270 def_bool n 2271 prompt "Debug CPU0 hotplug" 2272 depends on HOTPLUG_CPU 2273 help 2274 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2275 soon as possible and boots up userspace with CPU0 offlined. User 2276 can online CPU0 back after boot time. 2277 2278 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2279 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2280 compilation or giving cpu0_hotplug kernel parameter at boot. 2281 2282 If unsure, say N. 2283 2284config COMPAT_VDSO 2285 def_bool n 2286 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2287 depends on COMPAT_32 2288 help 2289 Certain buggy versions of glibc will crash if they are 2290 presented with a 32-bit vDSO that is not mapped at the address 2291 indicated in its segment table. 2292 2293 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2294 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2295 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2296 the only released version with the bug, but OpenSUSE 9 2297 contains a buggy "glibc 2.3.2". 2298 2299 The symptom of the bug is that everything crashes on startup, saying: 2300 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2301 2302 Saying Y here changes the default value of the vdso32 boot 2303 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2304 This works around the glibc bug but hurts performance. 2305 2306 If unsure, say N: if you are compiling your own kernel, you 2307 are unlikely to be using a buggy version of glibc. 2308 2309choice 2310 prompt "vsyscall table for legacy applications" 2311 depends on X86_64 2312 default LEGACY_VSYSCALL_XONLY 2313 help 2314 Legacy user code that does not know how to find the vDSO expects 2315 to be able to issue three syscalls by calling fixed addresses in 2316 kernel space. Since this location is not randomized with ASLR, 2317 it can be used to assist security vulnerability exploitation. 2318 2319 This setting can be changed at boot time via the kernel command 2320 line parameter vsyscall=[emulate|xonly|none]. 2321 2322 On a system with recent enough glibc (2.14 or newer) and no 2323 static binaries, you can say None without a performance penalty 2324 to improve security. 2325 2326 If unsure, select "Emulate execution only". 2327 2328 config LEGACY_VSYSCALL_EMULATE 2329 bool "Full emulation" 2330 help 2331 The kernel traps and emulates calls into the fixed vsyscall 2332 address mapping. This makes the mapping non-executable, but 2333 it still contains readable known contents, which could be 2334 used in certain rare security vulnerability exploits. This 2335 configuration is recommended when using legacy userspace 2336 that still uses vsyscalls along with legacy binary 2337 instrumentation tools that require code to be readable. 2338 2339 An example of this type of legacy userspace is running 2340 Pin on an old binary that still uses vsyscalls. 2341 2342 config LEGACY_VSYSCALL_XONLY 2343 bool "Emulate execution only" 2344 help 2345 The kernel traps and emulates calls into the fixed vsyscall 2346 address mapping and does not allow reads. This 2347 configuration is recommended when userspace might use the 2348 legacy vsyscall area but support for legacy binary 2349 instrumentation of legacy code is not needed. It mitigates 2350 certain uses of the vsyscall area as an ASLR-bypassing 2351 buffer. 2352 2353 config LEGACY_VSYSCALL_NONE 2354 bool "None" 2355 help 2356 There will be no vsyscall mapping at all. This will 2357 eliminate any risk of ASLR bypass due to the vsyscall 2358 fixed address mapping. Attempts to use the vsyscalls 2359 will be reported to dmesg, so that either old or 2360 malicious userspace programs can be identified. 2361 2362endchoice 2363 2364config CMDLINE_BOOL 2365 bool "Built-in kernel command line" 2366 help 2367 Allow for specifying boot arguments to the kernel at 2368 build time. On some systems (e.g. embedded ones), it is 2369 necessary or convenient to provide some or all of the 2370 kernel boot arguments with the kernel itself (that is, 2371 to not rely on the boot loader to provide them.) 2372 2373 To compile command line arguments into the kernel, 2374 set this option to 'Y', then fill in the 2375 boot arguments in CONFIG_CMDLINE. 2376 2377 Systems with fully functional boot loaders (i.e. non-embedded) 2378 should leave this option set to 'N'. 2379 2380config CMDLINE 2381 string "Built-in kernel command string" 2382 depends on CMDLINE_BOOL 2383 default "" 2384 help 2385 Enter arguments here that should be compiled into the kernel 2386 image and used at boot time. If the boot loader provides a 2387 command line at boot time, it is appended to this string to 2388 form the full kernel command line, when the system boots. 2389 2390 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2391 change this behavior. 2392 2393 In most cases, the command line (whether built-in or provided 2394 by the boot loader) should specify the device for the root 2395 file system. 2396 2397config CMDLINE_OVERRIDE 2398 bool "Built-in command line overrides boot loader arguments" 2399 depends on CMDLINE_BOOL && CMDLINE != "" 2400 help 2401 Set this option to 'Y' to have the kernel ignore the boot loader 2402 command line, and use ONLY the built-in command line. 2403 2404 This is used to work around broken boot loaders. This should 2405 be set to 'N' under normal conditions. 2406 2407config MODIFY_LDT_SYSCALL 2408 bool "Enable the LDT (local descriptor table)" if EXPERT 2409 default y 2410 help 2411 Linux can allow user programs to install a per-process x86 2412 Local Descriptor Table (LDT) using the modify_ldt(2) system 2413 call. This is required to run 16-bit or segmented code such as 2414 DOSEMU or some Wine programs. It is also used by some very old 2415 threading libraries. 2416 2417 Enabling this feature adds a small amount of overhead to 2418 context switches and increases the low-level kernel attack 2419 surface. Disabling it removes the modify_ldt(2) system call. 2420 2421 Saying 'N' here may make sense for embedded or server kernels. 2422 2423source "kernel/livepatch/Kconfig" 2424 2425endmenu 2426 2427config ARCH_HAS_ADD_PAGES 2428 def_bool y 2429 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2430 2431config ARCH_ENABLE_MEMORY_HOTPLUG 2432 def_bool y 2433 depends on X86_64 || (X86_32 && HIGHMEM) 2434 2435config ARCH_ENABLE_MEMORY_HOTREMOVE 2436 def_bool y 2437 depends on MEMORY_HOTPLUG 2438 2439config USE_PERCPU_NUMA_NODE_ID 2440 def_bool y 2441 depends on NUMA 2442 2443config ARCH_ENABLE_SPLIT_PMD_PTLOCK 2444 def_bool y 2445 depends on X86_64 || X86_PAE 2446 2447config ARCH_ENABLE_HUGEPAGE_MIGRATION 2448 def_bool y 2449 depends on X86_64 && HUGETLB_PAGE && MIGRATION 2450 2451config ARCH_ENABLE_THP_MIGRATION 2452 def_bool y 2453 depends on X86_64 && TRANSPARENT_HUGEPAGE 2454 2455menu "Power management and ACPI options" 2456 2457config ARCH_HIBERNATION_HEADER 2458 def_bool y 2459 depends on HIBERNATION 2460 2461source "kernel/power/Kconfig" 2462 2463source "drivers/acpi/Kconfig" 2464 2465config X86_APM_BOOT 2466 def_bool y 2467 depends on APM 2468 2469menuconfig APM 2470 tristate "APM (Advanced Power Management) BIOS support" 2471 depends on X86_32 && PM_SLEEP 2472 help 2473 APM is a BIOS specification for saving power using several different 2474 techniques. This is mostly useful for battery powered laptops with 2475 APM compliant BIOSes. If you say Y here, the system time will be 2476 reset after a RESUME operation, the /proc/apm device will provide 2477 battery status information, and user-space programs will receive 2478 notification of APM "events" (e.g. battery status change). 2479 2480 If you select "Y" here, you can disable actual use of the APM 2481 BIOS by passing the "apm=off" option to the kernel at boot time. 2482 2483 Note that the APM support is almost completely disabled for 2484 machines with more than one CPU. 2485 2486 In order to use APM, you will need supporting software. For location 2487 and more information, read <file:Documentation/power/apm-acpi.rst> 2488 and the Battery Powered Linux mini-HOWTO, available from 2489 <http://www.tldp.org/docs.html#howto>. 2490 2491 This driver does not spin down disk drives (see the hdparm(8) 2492 manpage ("man 8 hdparm") for that), and it doesn't turn off 2493 VESA-compliant "green" monitors. 2494 2495 This driver does not support the TI 4000M TravelMate and the ACER 2496 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2497 desktop machines also don't have compliant BIOSes, and this driver 2498 may cause those machines to panic during the boot phase. 2499 2500 Generally, if you don't have a battery in your machine, there isn't 2501 much point in using this driver and you should say N. If you get 2502 random kernel OOPSes or reboots that don't seem to be related to 2503 anything, try disabling/enabling this option (or disabling/enabling 2504 APM in your BIOS). 2505 2506 Some other things you should try when experiencing seemingly random, 2507 "weird" problems: 2508 2509 1) make sure that you have enough swap space and that it is 2510 enabled. 2511 2) pass the "no-hlt" option to the kernel 2512 3) switch on floating point emulation in the kernel and pass 2513 the "no387" option to the kernel 2514 4) pass the "floppy=nodma" option to the kernel 2515 5) pass the "mem=4M" option to the kernel (thereby disabling 2516 all but the first 4 MB of RAM) 2517 6) make sure that the CPU is not over clocked. 2518 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2519 8) disable the cache from your BIOS settings 2520 9) install a fan for the video card or exchange video RAM 2521 10) install a better fan for the CPU 2522 11) exchange RAM chips 2523 12) exchange the motherboard. 2524 2525 To compile this driver as a module, choose M here: the 2526 module will be called apm. 2527 2528if APM 2529 2530config APM_IGNORE_USER_SUSPEND 2531 bool "Ignore USER SUSPEND" 2532 help 2533 This option will ignore USER SUSPEND requests. On machines with a 2534 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2535 series notebooks, it is necessary to say Y because of a BIOS bug. 2536 2537config APM_DO_ENABLE 2538 bool "Enable PM at boot time" 2539 help 2540 Enable APM features at boot time. From page 36 of the APM BIOS 2541 specification: "When disabled, the APM BIOS does not automatically 2542 power manage devices, enter the Standby State, enter the Suspend 2543 State, or take power saving steps in response to CPU Idle calls." 2544 This driver will make CPU Idle calls when Linux is idle (unless this 2545 feature is turned off -- see "Do CPU IDLE calls", below). This 2546 should always save battery power, but more complicated APM features 2547 will be dependent on your BIOS implementation. You may need to turn 2548 this option off if your computer hangs at boot time when using APM 2549 support, or if it beeps continuously instead of suspending. Turn 2550 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2551 T400CDT. This is off by default since most machines do fine without 2552 this feature. 2553 2554config APM_CPU_IDLE 2555 depends on CPU_IDLE 2556 bool "Make CPU Idle calls when idle" 2557 help 2558 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2559 On some machines, this can activate improved power savings, such as 2560 a slowed CPU clock rate, when the machine is idle. These idle calls 2561 are made after the idle loop has run for some length of time (e.g., 2562 333 mS). On some machines, this will cause a hang at boot time or 2563 whenever the CPU becomes idle. (On machines with more than one CPU, 2564 this option does nothing.) 2565 2566config APM_DISPLAY_BLANK 2567 bool "Enable console blanking using APM" 2568 help 2569 Enable console blanking using the APM. Some laptops can use this to 2570 turn off the LCD backlight when the screen blanker of the Linux 2571 virtual console blanks the screen. Note that this is only used by 2572 the virtual console screen blanker, and won't turn off the backlight 2573 when using the X Window system. This also doesn't have anything to 2574 do with your VESA-compliant power-saving monitor. Further, this 2575 option doesn't work for all laptops -- it might not turn off your 2576 backlight at all, or it might print a lot of errors to the console, 2577 especially if you are using gpm. 2578 2579config APM_ALLOW_INTS 2580 bool "Allow interrupts during APM BIOS calls" 2581 help 2582 Normally we disable external interrupts while we are making calls to 2583 the APM BIOS as a measure to lessen the effects of a badly behaving 2584 BIOS implementation. The BIOS should reenable interrupts if it 2585 needs to. Unfortunately, some BIOSes do not -- especially those in 2586 many of the newer IBM Thinkpads. If you experience hangs when you 2587 suspend, try setting this to Y. Otherwise, say N. 2588 2589endif # APM 2590 2591source "drivers/cpufreq/Kconfig" 2592 2593source "drivers/cpuidle/Kconfig" 2594 2595source "drivers/idle/Kconfig" 2596 2597endmenu 2598 2599 2600menu "Bus options (PCI etc.)" 2601 2602choice 2603 prompt "PCI access mode" 2604 depends on X86_32 && PCI 2605 default PCI_GOANY 2606 help 2607 On PCI systems, the BIOS can be used to detect the PCI devices and 2608 determine their configuration. However, some old PCI motherboards 2609 have BIOS bugs and may crash if this is done. Also, some embedded 2610 PCI-based systems don't have any BIOS at all. Linux can also try to 2611 detect the PCI hardware directly without using the BIOS. 2612 2613 With this option, you can specify how Linux should detect the 2614 PCI devices. If you choose "BIOS", the BIOS will be used, 2615 if you choose "Direct", the BIOS won't be used, and if you 2616 choose "MMConfig", then PCI Express MMCONFIG will be used. 2617 If you choose "Any", the kernel will try MMCONFIG, then the 2618 direct access method and falls back to the BIOS if that doesn't 2619 work. If unsure, go with the default, which is "Any". 2620 2621config PCI_GOBIOS 2622 bool "BIOS" 2623 2624config PCI_GOMMCONFIG 2625 bool "MMConfig" 2626 2627config PCI_GODIRECT 2628 bool "Direct" 2629 2630config PCI_GOOLPC 2631 bool "OLPC XO-1" 2632 depends on OLPC 2633 2634config PCI_GOANY 2635 bool "Any" 2636 2637endchoice 2638 2639config PCI_BIOS 2640 def_bool y 2641 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2642 2643# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2644config PCI_DIRECT 2645 def_bool y 2646 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2647 2648config PCI_MMCONFIG 2649 bool "Support mmconfig PCI config space access" if X86_64 2650 default y 2651 depends on PCI && (ACPI || JAILHOUSE_GUEST) 2652 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2653 2654config PCI_OLPC 2655 def_bool y 2656 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2657 2658config PCI_XEN 2659 def_bool y 2660 depends on PCI && XEN 2661 select SWIOTLB_XEN 2662 2663config MMCONF_FAM10H 2664 def_bool y 2665 depends on X86_64 && PCI_MMCONFIG && ACPI 2666 2667config PCI_CNB20LE_QUIRK 2668 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2669 depends on PCI 2670 help 2671 Read the PCI windows out of the CNB20LE host bridge. This allows 2672 PCI hotplug to work on systems with the CNB20LE chipset which do 2673 not have ACPI. 2674 2675 There's no public spec for this chipset, and this functionality 2676 is known to be incomplete. 2677 2678 You should say N unless you know you need this. 2679 2680config ISA_BUS 2681 bool "ISA bus support on modern systems" if EXPERT 2682 help 2683 Expose ISA bus device drivers and options available for selection and 2684 configuration. Enable this option if your target machine has an ISA 2685 bus. ISA is an older system, displaced by PCI and newer bus 2686 architectures -- if your target machine is modern, it probably does 2687 not have an ISA bus. 2688 2689 If unsure, say N. 2690 2691# x86_64 have no ISA slots, but can have ISA-style DMA. 2692config ISA_DMA_API 2693 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2694 default y 2695 help 2696 Enables ISA-style DMA support for devices requiring such controllers. 2697 If unsure, say Y. 2698 2699if X86_32 2700 2701config ISA 2702 bool "ISA support" 2703 help 2704 Find out whether you have ISA slots on your motherboard. ISA is the 2705 name of a bus system, i.e. the way the CPU talks to the other stuff 2706 inside your box. Other bus systems are PCI, EISA, MicroChannel 2707 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2708 newer boards don't support it. If you have ISA, say Y, otherwise N. 2709 2710config SCx200 2711 tristate "NatSemi SCx200 support" 2712 help 2713 This provides basic support for National Semiconductor's 2714 (now AMD's) Geode processors. The driver probes for the 2715 PCI-IDs of several on-chip devices, so its a good dependency 2716 for other scx200_* drivers. 2717 2718 If compiled as a module, the driver is named scx200. 2719 2720config SCx200HR_TIMER 2721 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2722 depends on SCx200 2723 default y 2724 help 2725 This driver provides a clocksource built upon the on-chip 2726 27MHz high-resolution timer. Its also a workaround for 2727 NSC Geode SC-1100's buggy TSC, which loses time when the 2728 processor goes idle (as is done by the scheduler). The 2729 other workaround is idle=poll boot option. 2730 2731config OLPC 2732 bool "One Laptop Per Child support" 2733 depends on !X86_PAE 2734 select GPIOLIB 2735 select OF 2736 select OF_PROMTREE 2737 select IRQ_DOMAIN 2738 select OLPC_EC 2739 help 2740 Add support for detecting the unique features of the OLPC 2741 XO hardware. 2742 2743config OLPC_XO1_PM 2744 bool "OLPC XO-1 Power Management" 2745 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2746 help 2747 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2748 2749config OLPC_XO1_RTC 2750 bool "OLPC XO-1 Real Time Clock" 2751 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2752 help 2753 Add support for the XO-1 real time clock, which can be used as a 2754 programmable wakeup source. 2755 2756config OLPC_XO1_SCI 2757 bool "OLPC XO-1 SCI extras" 2758 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2759 depends on INPUT=y 2760 select POWER_SUPPLY 2761 help 2762 Add support for SCI-based features of the OLPC XO-1 laptop: 2763 - EC-driven system wakeups 2764 - Power button 2765 - Ebook switch 2766 - Lid switch 2767 - AC adapter status updates 2768 - Battery status updates 2769 2770config OLPC_XO15_SCI 2771 bool "OLPC XO-1.5 SCI extras" 2772 depends on OLPC && ACPI 2773 select POWER_SUPPLY 2774 help 2775 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2776 - EC-driven system wakeups 2777 - AC adapter status updates 2778 - Battery status updates 2779 2780config ALIX 2781 bool "PCEngines ALIX System Support (LED setup)" 2782 select GPIOLIB 2783 help 2784 This option enables system support for the PCEngines ALIX. 2785 At present this just sets up LEDs for GPIO control on 2786 ALIX2/3/6 boards. However, other system specific setup should 2787 get added here. 2788 2789 Note: You must still enable the drivers for GPIO and LED support 2790 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2791 2792 Note: You have to set alix.force=1 for boards with Award BIOS. 2793 2794config NET5501 2795 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2796 select GPIOLIB 2797 help 2798 This option enables system support for the Soekris Engineering net5501. 2799 2800config GEOS 2801 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2802 select GPIOLIB 2803 depends on DMI 2804 help 2805 This option enables system support for the Traverse Technologies GEOS. 2806 2807config TS5500 2808 bool "Technologic Systems TS-5500 platform support" 2809 depends on MELAN 2810 select CHECK_SIGNATURE 2811 select NEW_LEDS 2812 select LEDS_CLASS 2813 help 2814 This option enables system support for the Technologic Systems TS-5500. 2815 2816endif # X86_32 2817 2818config AMD_NB 2819 def_bool y 2820 depends on CPU_SUP_AMD && PCI 2821 2822config X86_SYSFB 2823 bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2824 help 2825 Firmwares often provide initial graphics framebuffers so the BIOS, 2826 bootloader or kernel can show basic video-output during boot for 2827 user-guidance and debugging. Historically, x86 used the VESA BIOS 2828 Extensions and EFI-framebuffers for this, which are mostly limited 2829 to x86. 2830 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2831 framebuffers so the new generic system-framebuffer drivers can be 2832 used on x86. If the framebuffer is not compatible with the generic 2833 modes, it is advertised as fallback platform framebuffer so legacy 2834 drivers like efifb, vesafb and uvesafb can pick it up. 2835 If this option is not selected, all system framebuffers are always 2836 marked as fallback platform framebuffers as usual. 2837 2838 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2839 not be able to pick up generic system framebuffers if this option 2840 is selected. You are highly encouraged to enable simplefb as 2841 replacement if you select this option. simplefb can correctly deal 2842 with generic system framebuffers. But you should still keep vesafb 2843 and others enabled as fallback if a system framebuffer is 2844 incompatible with simplefb. 2845 2846 If unsure, say Y. 2847 2848endmenu 2849 2850 2851menu "Binary Emulations" 2852 2853config IA32_EMULATION 2854 bool "IA32 Emulation" 2855 depends on X86_64 2856 select ARCH_WANT_OLD_COMPAT_IPC 2857 select BINFMT_ELF 2858 select COMPAT_OLD_SIGACTION 2859 help 2860 Include code to run legacy 32-bit programs under a 2861 64-bit kernel. You should likely turn this on, unless you're 2862 100% sure that you don't have any 32-bit programs left. 2863 2864config IA32_AOUT 2865 tristate "IA32 a.out support" 2866 depends on IA32_EMULATION 2867 depends on BROKEN 2868 help 2869 Support old a.out binaries in the 32bit emulation. 2870 2871config X86_X32 2872 bool "x32 ABI for 64-bit mode" 2873 depends on X86_64 2874 help 2875 Include code to run binaries for the x32 native 32-bit ABI 2876 for 64-bit processors. An x32 process gets access to the 2877 full 64-bit register file and wide data path while leaving 2878 pointers at 32 bits for smaller memory footprint. 2879 2880 You will need a recent binutils (2.22 or later) with 2881 elf32_x86_64 support enabled to compile a kernel with this 2882 option set. 2883 2884config COMPAT_32 2885 def_bool y 2886 depends on IA32_EMULATION || X86_32 2887 select HAVE_UID16 2888 select OLD_SIGSUSPEND3 2889 2890config COMPAT 2891 def_bool y 2892 depends on IA32_EMULATION || X86_X32 2893 2894if COMPAT 2895config COMPAT_FOR_U64_ALIGNMENT 2896 def_bool y 2897 2898config SYSVIPC_COMPAT 2899 def_bool y 2900 depends on SYSVIPC 2901endif 2902 2903endmenu 2904 2905 2906config HAVE_ATOMIC_IOMAP 2907 def_bool y 2908 depends on X86_32 2909 2910source "drivers/firmware/Kconfig" 2911 2912source "arch/x86/kvm/Kconfig" 2913 2914source "arch/x86/Kconfig.assembler" 2915