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 select ZONE_DMA32 37 38config FORCE_DYNAMIC_FTRACE 39 def_bool y 40 depends on X86_32 41 depends on FUNCTION_TRACER 42 select DYNAMIC_FTRACE 43 help 44 We keep the static function tracing (!DYNAMIC_FTRACE) around 45 in order to test the non static function tracing in the 46 generic code, as other architectures still use it. But we 47 only need to keep it around for x86_64. No need to keep it 48 for x86_32. For x86_32, force DYNAMIC_FTRACE. 49# 50# Arch settings 51# 52# ( Note that options that are marked 'if X86_64' could in principle be 53# ported to 32-bit as well. ) 54# 55config X86 56 def_bool y 57 # 58 # Note: keep this list sorted alphabetically 59 # 60 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 61 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 62 select ARCH_32BIT_OFF_T if X86_32 63 select ARCH_CLOCKSOURCE_INIT 64 select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 65 select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION 66 select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64 67 select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG 68 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE) 69 select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE 70 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 71 select ARCH_HAS_CACHE_LINE_SIZE 72 select ARCH_HAS_DEBUG_VIRTUAL 73 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 74 select ARCH_HAS_DEVMEM_IS_ALLOWED 75 select ARCH_HAS_EARLY_DEBUG if KGDB 76 select ARCH_HAS_ELF_RANDOMIZE 77 select ARCH_HAS_FAST_MULTIPLIER 78 select ARCH_HAS_FILTER_PGPROT 79 select ARCH_HAS_FORTIFY_SOURCE 80 select ARCH_HAS_GCOV_PROFILE_ALL 81 select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION 82 select ARCH_HAS_MEM_ENCRYPT 83 select ARCH_HAS_MEMBARRIER_SYNC_CORE 84 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 85 select ARCH_HAS_PMEM_API if X86_64 86 select ARCH_HAS_PTE_DEVMAP if X86_64 87 select ARCH_HAS_PTE_SPECIAL 88 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 89 select ARCH_HAS_COPY_MC if X86_64 90 select ARCH_HAS_SET_MEMORY 91 select ARCH_HAS_SET_DIRECT_MAP 92 select ARCH_HAS_STRICT_KERNEL_RWX 93 select ARCH_HAS_STRICT_MODULE_RWX 94 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 95 select ARCH_HAS_SYSCALL_WRAPPER 96 select ARCH_HAS_UBSAN_SANITIZE_ALL 97 select ARCH_HAS_DEBUG_WX 98 select ARCH_HAS_ZONE_DMA_SET if EXPERT 99 select ARCH_HAVE_NMI_SAFE_CMPXCHG 100 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 101 select ARCH_MIGHT_HAVE_PC_PARPORT 102 select ARCH_MIGHT_HAVE_PC_SERIO 103 select ARCH_STACKWALK 104 select ARCH_SUPPORTS_ACPI 105 select ARCH_SUPPORTS_ATOMIC_RMW 106 select ARCH_SUPPORTS_DEBUG_PAGEALLOC 107 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 108 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 109 select ARCH_SUPPORTS_LTO_CLANG 110 select ARCH_SUPPORTS_LTO_CLANG_THIN 111 select ARCH_USE_BUILTIN_BSWAP 112 select ARCH_USE_MEMTEST 113 select ARCH_USE_QUEUED_RWLOCKS 114 select ARCH_USE_QUEUED_SPINLOCKS 115 select ARCH_USE_SYM_ANNOTATIONS 116 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 117 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 118 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 119 select ARCH_WANTS_NO_INSTR 120 select ARCH_WANT_HUGE_PMD_SHARE 121 select ARCH_WANT_LD_ORPHAN_WARN 122 select ARCH_WANTS_THP_SWAP if X86_64 123 select ARCH_HAS_PARANOID_L1D_FLUSH 124 select BUILDTIME_TABLE_SORT 125 select CLKEVT_I8253 126 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 127 select CLOCKSOURCE_WATCHDOG 128 select DCACHE_WORD_ACCESS 129 select DYNAMIC_SIGFRAME 130 select EDAC_ATOMIC_SCRUB 131 select EDAC_SUPPORT 132 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 133 select GENERIC_CLOCKEVENTS_MIN_ADJUST 134 select GENERIC_CMOS_UPDATE 135 select GENERIC_CPU_AUTOPROBE 136 select GENERIC_CPU_VULNERABILITIES 137 select GENERIC_EARLY_IOREMAP 138 select GENERIC_ENTRY 139 select GENERIC_FIND_FIRST_BIT 140 select GENERIC_IOMAP 141 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 142 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 143 select GENERIC_IRQ_MIGRATION if SMP 144 select GENERIC_IRQ_PROBE 145 select GENERIC_IRQ_RESERVATION_MODE 146 select GENERIC_IRQ_SHOW 147 select GENERIC_PENDING_IRQ if SMP 148 select GENERIC_PTDUMP 149 select GENERIC_SMP_IDLE_THREAD 150 select GENERIC_TIME_VSYSCALL 151 select GENERIC_GETTIMEOFDAY 152 select GENERIC_VDSO_TIME_NS 153 select GUP_GET_PTE_LOW_HIGH if X86_PAE 154 select HARDIRQS_SW_RESEND 155 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 156 select HAVE_ACPI_APEI if ACPI 157 select HAVE_ACPI_APEI_NMI if ACPI 158 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 159 select HAVE_ARCH_AUDITSYSCALL 160 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 161 select HAVE_ARCH_JUMP_LABEL 162 select HAVE_ARCH_JUMP_LABEL_RELATIVE 163 select HAVE_ARCH_KASAN if X86_64 164 select HAVE_ARCH_KASAN_VMALLOC if X86_64 165 select HAVE_ARCH_KFENCE 166 select HAVE_ARCH_KGDB 167 select HAVE_ARCH_MMAP_RND_BITS if MMU 168 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 169 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 170 select HAVE_ARCH_PREL32_RELOCATIONS 171 select HAVE_ARCH_SECCOMP_FILTER 172 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 173 select HAVE_ARCH_STACKLEAK 174 select HAVE_ARCH_TRACEHOOK 175 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 176 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 177 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 178 select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 179 select HAVE_ARCH_VMAP_STACK if X86_64 180 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 181 select HAVE_ARCH_WITHIN_STACK_FRAMES 182 select HAVE_ASM_MODVERSIONS 183 select HAVE_CMPXCHG_DOUBLE 184 select HAVE_CMPXCHG_LOCAL 185 select HAVE_CONTEXT_TRACKING if X86_64 186 select HAVE_CONTEXT_TRACKING_OFFSTACK if HAVE_CONTEXT_TRACKING 187 select HAVE_C_RECORDMCOUNT 188 select HAVE_OBJTOOL_MCOUNT if STACK_VALIDATION 189 select HAVE_DEBUG_KMEMLEAK 190 select HAVE_DMA_CONTIGUOUS 191 select HAVE_DYNAMIC_FTRACE 192 select HAVE_DYNAMIC_FTRACE_WITH_REGS 193 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 194 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 195 select HAVE_SAMPLE_FTRACE_DIRECT if X86_64 196 select HAVE_SAMPLE_FTRACE_MULTI_DIRECT if X86_64 197 select HAVE_EBPF_JIT 198 select HAVE_EFFICIENT_UNALIGNED_ACCESS 199 select HAVE_EISA 200 select HAVE_EXIT_THREAD 201 select HAVE_FAST_GUP 202 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 203 select HAVE_FTRACE_MCOUNT_RECORD 204 select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) 205 select HAVE_FUNCTION_TRACER 206 select HAVE_GCC_PLUGINS 207 select HAVE_HW_BREAKPOINT 208 select HAVE_IOREMAP_PROT 209 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 210 select HAVE_IRQ_TIME_ACCOUNTING 211 select HAVE_KERNEL_BZIP2 212 select HAVE_KERNEL_GZIP 213 select HAVE_KERNEL_LZ4 214 select HAVE_KERNEL_LZMA 215 select HAVE_KERNEL_LZO 216 select HAVE_KERNEL_XZ 217 select HAVE_KERNEL_ZSTD 218 select HAVE_KPROBES 219 select HAVE_KPROBES_ON_FTRACE 220 select HAVE_FUNCTION_ERROR_INJECTION 221 select HAVE_KRETPROBES 222 select HAVE_KVM 223 select HAVE_LIVEPATCH if X86_64 224 select HAVE_MIXED_BREAKPOINTS_REGS 225 select HAVE_MOD_ARCH_SPECIFIC 226 select HAVE_MOVE_PMD 227 select HAVE_MOVE_PUD 228 select HAVE_NMI 229 select HAVE_OPTPROBES 230 select HAVE_PCSPKR_PLATFORM 231 select HAVE_PERF_EVENTS 232 select HAVE_PERF_EVENTS_NMI 233 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 234 select HAVE_PCI 235 select HAVE_PERF_REGS 236 select HAVE_PERF_USER_STACK_DUMP 237 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 238 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 239 select HAVE_REGS_AND_STACK_ACCESS_API 240 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 241 select HAVE_FUNCTION_ARG_ACCESS_API 242 select HAVE_SOFTIRQ_ON_OWN_STACK 243 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 244 select HAVE_STACK_VALIDATION if X86_64 245 select HAVE_STATIC_CALL 246 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION 247 select HAVE_PREEMPT_DYNAMIC 248 select HAVE_RSEQ 249 select HAVE_SYSCALL_TRACEPOINTS 250 select HAVE_UNSTABLE_SCHED_CLOCK 251 select HAVE_USER_RETURN_NOTIFIER 252 select HAVE_GENERIC_VDSO 253 select HOTPLUG_SMT if SMP 254 select IRQ_FORCED_THREADING 255 select NEED_SG_DMA_LENGTH 256 select PCI_DOMAINS if PCI 257 select PCI_LOCKLESS_CONFIG if PCI 258 select PERF_EVENTS 259 select RTC_LIB 260 select RTC_MC146818_LIB 261 select SPARSE_IRQ 262 select SRCU 263 select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE) 264 select SYSCTL_EXCEPTION_TRACE 265 select THREAD_INFO_IN_TASK 266 select TRACE_IRQFLAGS_SUPPORT 267 select USER_STACKTRACE_SUPPORT 268 select VIRT_TO_BUS 269 select HAVE_ARCH_KCSAN if X86_64 270 select X86_FEATURE_NAMES if PROC_FS 271 select PROC_PID_ARCH_STATUS if PROC_FS 272 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 273 274config INSTRUCTION_DECODER 275 def_bool y 276 depends on KPROBES || PERF_EVENTS || UPROBES 277 278config OUTPUT_FORMAT 279 string 280 default "elf32-i386" if X86_32 281 default "elf64-x86-64" if X86_64 282 283config LOCKDEP_SUPPORT 284 def_bool y 285 286config STACKTRACE_SUPPORT 287 def_bool y 288 289config MMU 290 def_bool y 291 292config ARCH_MMAP_RND_BITS_MIN 293 default 28 if 64BIT 294 default 8 295 296config ARCH_MMAP_RND_BITS_MAX 297 default 32 if 64BIT 298 default 16 299 300config ARCH_MMAP_RND_COMPAT_BITS_MIN 301 default 8 302 303config ARCH_MMAP_RND_COMPAT_BITS_MAX 304 default 16 305 306config SBUS 307 bool 308 309config GENERIC_ISA_DMA 310 def_bool y 311 depends on ISA_DMA_API 312 313config GENERIC_BUG 314 def_bool y 315 depends on BUG 316 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 317 318config GENERIC_BUG_RELATIVE_POINTERS 319 bool 320 321config ARCH_MAY_HAVE_PC_FDC 322 def_bool y 323 depends on ISA_DMA_API 324 325config GENERIC_CALIBRATE_DELAY 326 def_bool y 327 328config ARCH_HAS_CPU_RELAX 329 def_bool y 330 331config ARCH_HAS_FILTER_PGPROT 332 def_bool y 333 334config HAVE_SETUP_PER_CPU_AREA 335 def_bool y 336 337config NEED_PER_CPU_EMBED_FIRST_CHUNK 338 def_bool y 339 340config NEED_PER_CPU_PAGE_FIRST_CHUNK 341 def_bool y 342 343config ARCH_HIBERNATION_POSSIBLE 344 def_bool y 345 346config ARCH_NR_GPIO 347 int 348 default 1024 if X86_64 349 default 512 350 351config ARCH_SUSPEND_POSSIBLE 352 def_bool y 353 354config ARCH_WANT_GENERAL_HUGETLB 355 def_bool y 356 357config AUDIT_ARCH 358 def_bool y if X86_64 359 360config KASAN_SHADOW_OFFSET 361 hex 362 depends on KASAN 363 default 0xdffffc0000000000 364 365config HAVE_INTEL_TXT 366 def_bool y 367 depends on INTEL_IOMMU && ACPI 368 369config X86_32_SMP 370 def_bool y 371 depends on X86_32 && SMP 372 373config X86_64_SMP 374 def_bool y 375 depends on X86_64 && SMP 376 377config ARCH_SUPPORTS_UPROBES 378 def_bool y 379 380config FIX_EARLYCON_MEM 381 def_bool y 382 383config DYNAMIC_PHYSICAL_MASK 384 bool 385 386config PGTABLE_LEVELS 387 int 388 default 5 if X86_5LEVEL 389 default 4 if X86_64 390 default 3 if X86_PAE 391 default 2 392 393config CC_HAS_SANE_STACKPROTECTOR 394 bool 395 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 396 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 397 help 398 We have to make sure stack protector is unconditionally disabled if 399 the compiler produces broken code or if it does not let us control 400 the segment on 32-bit kernels. 401 402menu "Processor type and features" 403 404config SMP 405 bool "Symmetric multi-processing support" 406 help 407 This enables support for systems with more than one CPU. If you have 408 a system with only one CPU, say N. If you have a system with more 409 than one CPU, say Y. 410 411 If you say N here, the kernel will run on uni- and multiprocessor 412 machines, but will use only one CPU of a multiprocessor machine. If 413 you say Y here, the kernel will run on many, but not all, 414 uniprocessor machines. On a uniprocessor machine, the kernel 415 will run faster if you say N here. 416 417 Note that if you say Y here and choose architecture "586" or 418 "Pentium" under "Processor family", the kernel will not work on 486 419 architectures. Similarly, multiprocessor kernels for the "PPro" 420 architecture may not work on all Pentium based boards. 421 422 People using multiprocessor machines who say Y here should also say 423 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 424 Management" code will be disabled if you say Y here. 425 426 See also <file:Documentation/x86/i386/IO-APIC.rst>, 427 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 428 <http://www.tldp.org/docs.html#howto>. 429 430 If you don't know what to do here, say N. 431 432config X86_FEATURE_NAMES 433 bool "Processor feature human-readable names" if EMBEDDED 434 default y 435 help 436 This option compiles in a table of x86 feature bits and corresponding 437 names. This is required to support /proc/cpuinfo and a few kernel 438 messages. You can disable this to save space, at the expense of 439 making those few kernel messages show numeric feature bits instead. 440 441 If in doubt, say Y. 442 443config X86_X2APIC 444 bool "Support x2apic" 445 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 446 help 447 This enables x2apic support on CPUs that have this feature. 448 449 This allows 32-bit apic IDs (so it can support very large systems), 450 and accesses the local apic via MSRs not via mmio. 451 452 If you don't know what to do here, say N. 453 454config X86_MPPARSE 455 bool "Enable MPS table" if ACPI 456 default y 457 depends on X86_LOCAL_APIC 458 help 459 For old smp systems that do not have proper acpi support. Newer systems 460 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 461 462config GOLDFISH 463 def_bool y 464 depends on X86_GOLDFISH 465 466config RETPOLINE 467 bool "Avoid speculative indirect branches in kernel" 468 default y 469 help 470 Compile kernel with the retpoline compiler options to guard against 471 kernel-to-user data leaks by avoiding speculative indirect 472 branches. Requires a compiler with -mindirect-branch=thunk-extern 473 support for full protection. The kernel may run slower. 474 475config X86_CPU_RESCTRL 476 bool "x86 CPU resource control support" 477 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 478 select KERNFS 479 select PROC_CPU_RESCTRL if PROC_FS 480 help 481 Enable x86 CPU resource control support. 482 483 Provide support for the allocation and monitoring of system resources 484 usage by the CPU. 485 486 Intel calls this Intel Resource Director Technology 487 (Intel(R) RDT). More information about RDT can be found in the 488 Intel x86 Architecture Software Developer Manual. 489 490 AMD calls this AMD Platform Quality of Service (AMD QoS). 491 More information about AMD QoS can be found in the AMD64 Technology 492 Platform Quality of Service Extensions manual. 493 494 Say N if unsure. 495 496if X86_32 497config X86_BIGSMP 498 bool "Support for big SMP systems with more than 8 CPUs" 499 depends on SMP 500 help 501 This option is needed for the systems that have more than 8 CPUs. 502 503config X86_EXTENDED_PLATFORM 504 bool "Support for extended (non-PC) x86 platforms" 505 default y 506 help 507 If you disable this option then the kernel will only support 508 standard PC platforms. (which covers the vast majority of 509 systems out there.) 510 511 If you enable this option then you'll be able to select support 512 for the following (non-PC) 32 bit x86 platforms: 513 Goldfish (Android emulator) 514 AMD Elan 515 RDC R-321x SoC 516 SGI 320/540 (Visual Workstation) 517 STA2X11-based (e.g. Northville) 518 Moorestown MID devices 519 520 If you have one of these systems, or if you want to build a 521 generic distribution kernel, say Y here - otherwise say N. 522endif 523 524if X86_64 525config X86_EXTENDED_PLATFORM 526 bool "Support for extended (non-PC) x86 platforms" 527 default y 528 help 529 If you disable this option then the kernel will only support 530 standard PC platforms. (which covers the vast majority of 531 systems out there.) 532 533 If you enable this option then you'll be able to select support 534 for the following (non-PC) 64 bit x86 platforms: 535 Numascale NumaChip 536 ScaleMP vSMP 537 SGI Ultraviolet 538 539 If you have one of these systems, or if you want to build a 540 generic distribution kernel, say Y here - otherwise say N. 541endif 542# This is an alphabetically sorted list of 64 bit extended platforms 543# Please maintain the alphabetic order if and when there are additions 544config X86_NUMACHIP 545 bool "Numascale NumaChip" 546 depends on X86_64 547 depends on X86_EXTENDED_PLATFORM 548 depends on NUMA 549 depends on SMP 550 depends on X86_X2APIC 551 depends on PCI_MMCONFIG 552 help 553 Adds support for Numascale NumaChip large-SMP systems. Needed to 554 enable more than ~168 cores. 555 If you don't have one of these, you should say N here. 556 557config X86_VSMP 558 bool "ScaleMP vSMP" 559 select HYPERVISOR_GUEST 560 select PARAVIRT 561 depends on X86_64 && PCI 562 depends on X86_EXTENDED_PLATFORM 563 depends on SMP 564 help 565 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 566 supposed to run on these EM64T-based machines. Only choose this option 567 if you have one of these machines. 568 569config X86_UV 570 bool "SGI Ultraviolet" 571 depends on X86_64 572 depends on X86_EXTENDED_PLATFORM 573 depends on NUMA 574 depends on EFI 575 depends on KEXEC_CORE 576 depends on X86_X2APIC 577 depends on PCI 578 help 579 This option is needed in order to support SGI Ultraviolet systems. 580 If you don't have one of these, you should say N here. 581 582# Following is an alphabetically sorted list of 32 bit extended platforms 583# Please maintain the alphabetic order if and when there are additions 584 585config X86_GOLDFISH 586 bool "Goldfish (Virtual Platform)" 587 depends on X86_EXTENDED_PLATFORM 588 help 589 Enable support for the Goldfish virtual platform used primarily 590 for Android development. Unless you are building for the Android 591 Goldfish emulator say N here. 592 593config X86_INTEL_CE 594 bool "CE4100 TV platform" 595 depends on PCI 596 depends on PCI_GODIRECT 597 depends on X86_IO_APIC 598 depends on X86_32 599 depends on X86_EXTENDED_PLATFORM 600 select X86_REBOOTFIXUPS 601 select OF 602 select OF_EARLY_FLATTREE 603 help 604 Select for the Intel CE media processor (CE4100) SOC. 605 This option compiles in support for the CE4100 SOC for settop 606 boxes and media devices. 607 608config X86_INTEL_MID 609 bool "Intel MID platform support" 610 depends on X86_EXTENDED_PLATFORM 611 depends on X86_PLATFORM_DEVICES 612 depends on PCI 613 depends on X86_64 || (PCI_GOANY && X86_32) 614 depends on X86_IO_APIC 615 select I2C 616 select DW_APB_TIMER 617 select INTEL_SCU_PCI 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_CLUSTER 1007 bool "Cluster scheduler support" 1008 depends on SMP 1009 default y 1010 help 1011 Cluster scheduler support improves the CPU scheduler's decision 1012 making when dealing with machines that have clusters of CPUs. 1013 Cluster usually means a couple of CPUs which are placed closely 1014 by sharing mid-level caches, last-level cache tags or internal 1015 busses. 1016 1017config SCHED_SMT 1018 def_bool y if SMP 1019 1020config SCHED_MC 1021 def_bool y 1022 prompt "Multi-core scheduler support" 1023 depends on SMP 1024 help 1025 Multi-core scheduler support improves the CPU scheduler's decision 1026 making when dealing with multi-core CPU chips at a cost of slightly 1027 increased overhead in some places. If unsure say N here. 1028 1029config SCHED_MC_PRIO 1030 bool "CPU core priorities scheduler support" 1031 depends on SCHED_MC && CPU_SUP_INTEL 1032 select X86_INTEL_PSTATE 1033 select CPU_FREQ 1034 default y 1035 help 1036 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1037 core ordering determined at manufacturing time, which allows 1038 certain cores to reach higher turbo frequencies (when running 1039 single threaded workloads) than others. 1040 1041 Enabling this kernel feature teaches the scheduler about 1042 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1043 scheduler's CPU selection logic accordingly, so that higher 1044 overall system performance can be achieved. 1045 1046 This feature will have no effect on CPUs without this feature. 1047 1048 If unsure say Y here. 1049 1050config UP_LATE_INIT 1051 def_bool y 1052 depends on !SMP && X86_LOCAL_APIC 1053 1054config X86_UP_APIC 1055 bool "Local APIC support on uniprocessors" if !PCI_MSI 1056 default PCI_MSI 1057 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1058 help 1059 A local APIC (Advanced Programmable Interrupt Controller) is an 1060 integrated interrupt controller in the CPU. If you have a single-CPU 1061 system which has a processor with a local APIC, you can say Y here to 1062 enable and use it. If you say Y here even though your machine doesn't 1063 have a local APIC, then the kernel will still run with no slowdown at 1064 all. The local APIC supports CPU-generated self-interrupts (timer, 1065 performance counters), and the NMI watchdog which detects hard 1066 lockups. 1067 1068config X86_UP_IOAPIC 1069 bool "IO-APIC support on uniprocessors" 1070 depends on X86_UP_APIC 1071 help 1072 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1073 SMP-capable replacement for PC-style interrupt controllers. Most 1074 SMP systems and many recent uniprocessor systems have one. 1075 1076 If you have a single-CPU system with an IO-APIC, you can say Y here 1077 to use it. If you say Y here even though your machine doesn't have 1078 an IO-APIC, then the kernel will still run with no slowdown at all. 1079 1080config X86_LOCAL_APIC 1081 def_bool y 1082 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1083 select IRQ_DOMAIN_HIERARCHY 1084 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1085 1086config X86_IO_APIC 1087 def_bool y 1088 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1089 1090config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1091 bool "Reroute for broken boot IRQs" 1092 depends on X86_IO_APIC 1093 help 1094 This option enables a workaround that fixes a source of 1095 spurious interrupts. This is recommended when threaded 1096 interrupt handling is used on systems where the generation of 1097 superfluous "boot interrupts" cannot be disabled. 1098 1099 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1100 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1101 kernel does during interrupt handling). On chipsets where this 1102 boot IRQ generation cannot be disabled, this workaround keeps 1103 the original IRQ line masked so that only the equivalent "boot 1104 IRQ" is delivered to the CPUs. The workaround also tells the 1105 kernel to set up the IRQ handler on the boot IRQ line. In this 1106 way only one interrupt is delivered to the kernel. Otherwise 1107 the spurious second interrupt may cause the kernel to bring 1108 down (vital) interrupt lines. 1109 1110 Only affects "broken" chipsets. Interrupt sharing may be 1111 increased on these systems. 1112 1113config X86_MCE 1114 bool "Machine Check / overheating reporting" 1115 select GENERIC_ALLOCATOR 1116 default y 1117 help 1118 Machine Check support allows the processor to notify the 1119 kernel if it detects a problem (e.g. overheating, data corruption). 1120 The action the kernel takes depends on the severity of the problem, 1121 ranging from warning messages to halting the machine. 1122 1123config X86_MCELOG_LEGACY 1124 bool "Support for deprecated /dev/mcelog character device" 1125 depends on X86_MCE 1126 help 1127 Enable support for /dev/mcelog which is needed by the old mcelog 1128 userspace logging daemon. Consider switching to the new generation 1129 rasdaemon solution. 1130 1131config X86_MCE_INTEL 1132 def_bool y 1133 prompt "Intel MCE features" 1134 depends on X86_MCE && X86_LOCAL_APIC 1135 help 1136 Additional support for intel specific MCE features such as 1137 the thermal monitor. 1138 1139config X86_MCE_AMD 1140 def_bool y 1141 prompt "AMD MCE features" 1142 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1143 help 1144 Additional support for AMD specific MCE features such as 1145 the DRAM Error Threshold. 1146 1147config X86_ANCIENT_MCE 1148 bool "Support for old Pentium 5 / WinChip machine checks" 1149 depends on X86_32 && X86_MCE 1150 help 1151 Include support for machine check handling on old Pentium 5 or WinChip 1152 systems. These typically need to be enabled explicitly on the command 1153 line. 1154 1155config X86_MCE_THRESHOLD 1156 depends on X86_MCE_AMD || X86_MCE_INTEL 1157 def_bool y 1158 1159config X86_MCE_INJECT 1160 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1161 tristate "Machine check injector support" 1162 help 1163 Provide support for injecting machine checks for testing purposes. 1164 If you don't know what a machine check is and you don't do kernel 1165 QA it is safe to say n. 1166 1167source "arch/x86/events/Kconfig" 1168 1169config X86_LEGACY_VM86 1170 bool "Legacy VM86 support" 1171 depends on X86_32 1172 help 1173 This option allows user programs to put the CPU into V8086 1174 mode, which is an 80286-era approximation of 16-bit real mode. 1175 1176 Some very old versions of X and/or vbetool require this option 1177 for user mode setting. Similarly, DOSEMU will use it if 1178 available to accelerate real mode DOS programs. However, any 1179 recent version of DOSEMU, X, or vbetool should be fully 1180 functional even without kernel VM86 support, as they will all 1181 fall back to software emulation. Nevertheless, if you are using 1182 a 16-bit DOS program where 16-bit performance matters, vm86 1183 mode might be faster than emulation and you might want to 1184 enable this option. 1185 1186 Note that any app that works on a 64-bit kernel is unlikely to 1187 need this option, as 64-bit kernels don't, and can't, support 1188 V8086 mode. This option is also unrelated to 16-bit protected 1189 mode and is not needed to run most 16-bit programs under Wine. 1190 1191 Enabling this option increases the complexity of the kernel 1192 and slows down exception handling a tiny bit. 1193 1194 If unsure, say N here. 1195 1196config VM86 1197 bool 1198 default X86_LEGACY_VM86 1199 1200config X86_16BIT 1201 bool "Enable support for 16-bit segments" if EXPERT 1202 default y 1203 depends on MODIFY_LDT_SYSCALL 1204 help 1205 This option is required by programs like Wine to run 16-bit 1206 protected mode legacy code on x86 processors. Disabling 1207 this option saves about 300 bytes on i386, or around 6K text 1208 plus 16K runtime memory on x86-64, 1209 1210config X86_ESPFIX32 1211 def_bool y 1212 depends on X86_16BIT && X86_32 1213 1214config X86_ESPFIX64 1215 def_bool y 1216 depends on X86_16BIT && X86_64 1217 1218config X86_VSYSCALL_EMULATION 1219 bool "Enable vsyscall emulation" if EXPERT 1220 default y 1221 depends on X86_64 1222 help 1223 This enables emulation of the legacy vsyscall page. Disabling 1224 it is roughly equivalent to booting with vsyscall=none, except 1225 that it will also disable the helpful warning if a program 1226 tries to use a vsyscall. With this option set to N, offending 1227 programs will just segfault, citing addresses of the form 1228 0xffffffffff600?00. 1229 1230 This option is required by many programs built before 2013, and 1231 care should be used even with newer programs if set to N. 1232 1233 Disabling this option saves about 7K of kernel size and 1234 possibly 4K of additional runtime pagetable memory. 1235 1236config X86_IOPL_IOPERM 1237 bool "IOPERM and IOPL Emulation" 1238 default y 1239 help 1240 This enables the ioperm() and iopl() syscalls which are necessary 1241 for legacy applications. 1242 1243 Legacy IOPL support is an overbroad mechanism which allows user 1244 space aside of accessing all 65536 I/O ports also to disable 1245 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1246 capabilities and permission from potentially active security 1247 modules. 1248 1249 The emulation restricts the functionality of the syscall to 1250 only allowing the full range I/O port access, but prevents the 1251 ability to disable interrupts from user space which would be 1252 granted if the hardware IOPL mechanism would be used. 1253 1254config TOSHIBA 1255 tristate "Toshiba Laptop support" 1256 depends on X86_32 1257 help 1258 This adds a driver to safely access the System Management Mode of 1259 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1260 not work on models with a Phoenix BIOS. The System Management Mode 1261 is used to set the BIOS and power saving options on Toshiba portables. 1262 1263 For information on utilities to make use of this driver see the 1264 Toshiba Linux utilities web site at: 1265 <http://www.buzzard.org.uk/toshiba/>. 1266 1267 Say Y if you intend to run this kernel on a Toshiba portable. 1268 Say N otherwise. 1269 1270config I8K 1271 tristate "Dell i8k legacy laptop support" 1272 depends on HWMON 1273 depends on PROC_FS 1274 select SENSORS_DELL_SMM 1275 help 1276 This option enables legacy /proc/i8k userspace interface in hwmon 1277 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1278 temperature and allows controlling fan speeds of Dell laptops via 1279 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1280 it reports also power and hotkey status. For fan speed control is 1281 needed userspace package i8kutils. 1282 1283 Say Y if you intend to run this kernel on old Dell laptops or want to 1284 use userspace package i8kutils. 1285 Say N otherwise. 1286 1287config X86_REBOOTFIXUPS 1288 bool "Enable X86 board specific fixups for reboot" 1289 depends on X86_32 1290 help 1291 This enables chipset and/or board specific fixups to be done 1292 in order to get reboot to work correctly. This is only needed on 1293 some combinations of hardware and BIOS. The symptom, for which 1294 this config is intended, is when reboot ends with a stalled/hung 1295 system. 1296 1297 Currently, the only fixup is for the Geode machines using 1298 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1299 1300 Say Y if you want to enable the fixup. Currently, it's safe to 1301 enable this option even if you don't need it. 1302 Say N otherwise. 1303 1304config MICROCODE 1305 bool "CPU microcode loading support" 1306 default y 1307 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1308 help 1309 If you say Y here, you will be able to update the microcode on 1310 Intel and AMD processors. The Intel support is for the IA32 family, 1311 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1312 AMD support is for families 0x10 and later. You will obviously need 1313 the actual microcode binary data itself which is not shipped with 1314 the Linux kernel. 1315 1316 The preferred method to load microcode from a detached initrd is described 1317 in Documentation/x86/microcode.rst. For that you need to enable 1318 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1319 initrd for microcode blobs. 1320 1321 In addition, you can build the microcode into the kernel. For that you 1322 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1323 config option. 1324 1325config MICROCODE_INTEL 1326 bool "Intel microcode loading support" 1327 depends on MICROCODE 1328 default MICROCODE 1329 help 1330 This options enables microcode patch loading support for Intel 1331 processors. 1332 1333 For the current Intel microcode data package go to 1334 <https://downloadcenter.intel.com> and search for 1335 'Linux Processor Microcode Data File'. 1336 1337config MICROCODE_AMD 1338 bool "AMD microcode loading support" 1339 depends on MICROCODE 1340 help 1341 If you select this option, microcode patch loading support for AMD 1342 processors will be enabled. 1343 1344config MICROCODE_OLD_INTERFACE 1345 bool "Ancient loading interface (DEPRECATED)" 1346 default n 1347 depends on MICROCODE 1348 help 1349 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1350 which was used by userspace tools like iucode_tool and microcode.ctl. 1351 It is inadequate because it runs too late to be able to properly 1352 load microcode on a machine and it needs special tools. Instead, you 1353 should've switched to the early loading method with the initrd or 1354 builtin microcode by now: Documentation/x86/microcode.rst 1355 1356config X86_MSR 1357 tristate "/dev/cpu/*/msr - Model-specific register support" 1358 help 1359 This device gives privileged processes access to the x86 1360 Model-Specific Registers (MSRs). It is a character device with 1361 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1362 MSR accesses are directed to a specific CPU on multi-processor 1363 systems. 1364 1365config X86_CPUID 1366 tristate "/dev/cpu/*/cpuid - CPU information support" 1367 help 1368 This device gives processes access to the x86 CPUID instruction to 1369 be executed on a specific processor. It is a character device 1370 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1371 /dev/cpu/31/cpuid. 1372 1373choice 1374 prompt "High Memory Support" 1375 default HIGHMEM4G 1376 depends on X86_32 1377 1378config NOHIGHMEM 1379 bool "off" 1380 help 1381 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1382 However, the address space of 32-bit x86 processors is only 4 1383 Gigabytes large. That means that, if you have a large amount of 1384 physical memory, not all of it can be "permanently mapped" by the 1385 kernel. The physical memory that's not permanently mapped is called 1386 "high memory". 1387 1388 If you are compiling a kernel which will never run on a machine with 1389 more than 1 Gigabyte total physical RAM, answer "off" here (default 1390 choice and suitable for most users). This will result in a "3GB/1GB" 1391 split: 3GB are mapped so that each process sees a 3GB virtual memory 1392 space and the remaining part of the 4GB virtual memory space is used 1393 by the kernel to permanently map as much physical memory as 1394 possible. 1395 1396 If the machine has between 1 and 4 Gigabytes physical RAM, then 1397 answer "4GB" here. 1398 1399 If more than 4 Gigabytes is used then answer "64GB" here. This 1400 selection turns Intel PAE (Physical Address Extension) mode on. 1401 PAE implements 3-level paging on IA32 processors. PAE is fully 1402 supported by Linux, PAE mode is implemented on all recent Intel 1403 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1404 then the kernel will not boot on CPUs that don't support PAE! 1405 1406 The actual amount of total physical memory will either be 1407 auto detected or can be forced by using a kernel command line option 1408 such as "mem=256M". (Try "man bootparam" or see the documentation of 1409 your boot loader (lilo or loadlin) about how to pass options to the 1410 kernel at boot time.) 1411 1412 If unsure, say "off". 1413 1414config HIGHMEM4G 1415 bool "4GB" 1416 help 1417 Select this if you have a 32-bit processor and between 1 and 4 1418 gigabytes of physical RAM. 1419 1420config HIGHMEM64G 1421 bool "64GB" 1422 depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6 1423 select X86_PAE 1424 help 1425 Select this if you have a 32-bit processor and more than 4 1426 gigabytes of physical RAM. 1427 1428endchoice 1429 1430choice 1431 prompt "Memory split" if EXPERT 1432 default VMSPLIT_3G 1433 depends on X86_32 1434 help 1435 Select the desired split between kernel and user memory. 1436 1437 If the address range available to the kernel is less than the 1438 physical memory installed, the remaining memory will be available 1439 as "high memory". Accessing high memory is a little more costly 1440 than low memory, as it needs to be mapped into the kernel first. 1441 Note that increasing the kernel address space limits the range 1442 available to user programs, making the address space there 1443 tighter. Selecting anything other than the default 3G/1G split 1444 will also likely make your kernel incompatible with binary-only 1445 kernel modules. 1446 1447 If you are not absolutely sure what you are doing, leave this 1448 option alone! 1449 1450 config VMSPLIT_3G 1451 bool "3G/1G user/kernel split" 1452 config VMSPLIT_3G_OPT 1453 depends on !X86_PAE 1454 bool "3G/1G user/kernel split (for full 1G low memory)" 1455 config VMSPLIT_2G 1456 bool "2G/2G user/kernel split" 1457 config VMSPLIT_2G_OPT 1458 depends on !X86_PAE 1459 bool "2G/2G user/kernel split (for full 2G low memory)" 1460 config VMSPLIT_1G 1461 bool "1G/3G user/kernel split" 1462endchoice 1463 1464config PAGE_OFFSET 1465 hex 1466 default 0xB0000000 if VMSPLIT_3G_OPT 1467 default 0x80000000 if VMSPLIT_2G 1468 default 0x78000000 if VMSPLIT_2G_OPT 1469 default 0x40000000 if VMSPLIT_1G 1470 default 0xC0000000 1471 depends on X86_32 1472 1473config HIGHMEM 1474 def_bool y 1475 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1476 1477config X86_PAE 1478 bool "PAE (Physical Address Extension) Support" 1479 depends on X86_32 && !HIGHMEM4G 1480 select PHYS_ADDR_T_64BIT 1481 select SWIOTLB 1482 help 1483 PAE is required for NX support, and furthermore enables 1484 larger swapspace support for non-overcommit purposes. It 1485 has the cost of more pagetable lookup overhead, and also 1486 consumes more pagetable space per process. 1487 1488config X86_5LEVEL 1489 bool "Enable 5-level page tables support" 1490 default y 1491 select DYNAMIC_MEMORY_LAYOUT 1492 select SPARSEMEM_VMEMMAP 1493 depends on X86_64 1494 help 1495 5-level paging enables access to larger address space: 1496 upto 128 PiB of virtual address space and 4 PiB of 1497 physical address space. 1498 1499 It will be supported by future Intel CPUs. 1500 1501 A kernel with the option enabled can be booted on machines that 1502 support 4- or 5-level paging. 1503 1504 See Documentation/x86/x86_64/5level-paging.rst for more 1505 information. 1506 1507 Say N if unsure. 1508 1509config X86_DIRECT_GBPAGES 1510 def_bool y 1511 depends on X86_64 1512 help 1513 Certain kernel features effectively disable kernel 1514 linear 1 GB mappings (even if the CPU otherwise 1515 supports them), so don't confuse the user by printing 1516 that we have them enabled. 1517 1518config X86_CPA_STATISTICS 1519 bool "Enable statistic for Change Page Attribute" 1520 depends on DEBUG_FS 1521 help 1522 Expose statistics about the Change Page Attribute mechanism, which 1523 helps to determine the effectiveness of preserving large and huge 1524 page mappings when mapping protections are changed. 1525 1526config X86_MEM_ENCRYPT 1527 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1528 select DYNAMIC_PHYSICAL_MASK 1529 select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS 1530 def_bool n 1531 1532config AMD_MEM_ENCRYPT 1533 bool "AMD Secure Memory Encryption (SME) support" 1534 depends on X86_64 && CPU_SUP_AMD 1535 select DMA_COHERENT_POOL 1536 select ARCH_USE_MEMREMAP_PROT 1537 select INSTRUCTION_DECODER 1538 select ARCH_HAS_CC_PLATFORM 1539 select X86_MEM_ENCRYPT 1540 help 1541 Say yes to enable support for the encryption of system memory. 1542 This requires an AMD processor that supports Secure Memory 1543 Encryption (SME). 1544 1545config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1546 bool "Activate AMD Secure Memory Encryption (SME) by default" 1547 depends on AMD_MEM_ENCRYPT 1548 help 1549 Say yes to have system memory encrypted by default if running on 1550 an AMD processor that supports Secure Memory Encryption (SME). 1551 1552 If set to Y, then the encryption of system memory can be 1553 deactivated with the mem_encrypt=off command line option. 1554 1555 If set to N, then the encryption of system memory can be 1556 activated with the mem_encrypt=on command line option. 1557 1558# Common NUMA Features 1559config NUMA 1560 bool "NUMA Memory Allocation and Scheduler Support" 1561 depends on SMP 1562 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1563 default y if X86_BIGSMP 1564 help 1565 Enable NUMA (Non-Uniform Memory Access) support. 1566 1567 The kernel will try to allocate memory used by a CPU on the 1568 local memory controller of the CPU and add some more 1569 NUMA awareness to the kernel. 1570 1571 For 64-bit this is recommended if the system is Intel Core i7 1572 (or later), AMD Opteron, or EM64T NUMA. 1573 1574 For 32-bit this is only needed if you boot a 32-bit 1575 kernel on a 64-bit NUMA platform. 1576 1577 Otherwise, you should say N. 1578 1579config AMD_NUMA 1580 def_bool y 1581 prompt "Old style AMD Opteron NUMA detection" 1582 depends on X86_64 && NUMA && PCI 1583 help 1584 Enable AMD NUMA node topology detection. You should say Y here if 1585 you have a multi processor AMD system. This uses an old method to 1586 read the NUMA configuration directly from the builtin Northbridge 1587 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1588 which also takes priority if both are compiled in. 1589 1590config X86_64_ACPI_NUMA 1591 def_bool y 1592 prompt "ACPI NUMA detection" 1593 depends on X86_64 && NUMA && ACPI && PCI 1594 select ACPI_NUMA 1595 help 1596 Enable ACPI SRAT based node topology detection. 1597 1598config NUMA_EMU 1599 bool "NUMA emulation" 1600 depends on NUMA 1601 help 1602 Enable NUMA emulation. A flat machine will be split 1603 into virtual nodes when booted with "numa=fake=N", where N is the 1604 number of nodes. This is only useful for debugging. 1605 1606config NODES_SHIFT 1607 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1608 range 1 10 1609 default "10" if MAXSMP 1610 default "6" if X86_64 1611 default "3" 1612 depends on NUMA 1613 help 1614 Specify the maximum number of NUMA Nodes available on the target 1615 system. Increases memory reserved to accommodate various tables. 1616 1617config ARCH_FLATMEM_ENABLE 1618 def_bool y 1619 depends on X86_32 && !NUMA 1620 1621config ARCH_SPARSEMEM_ENABLE 1622 def_bool y 1623 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1624 select SPARSEMEM_STATIC if X86_32 1625 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1626 1627config ARCH_SPARSEMEM_DEFAULT 1628 def_bool X86_64 || (NUMA && X86_32) 1629 1630config ARCH_SELECT_MEMORY_MODEL 1631 def_bool y 1632 depends on ARCH_SPARSEMEM_ENABLE 1633 1634config ARCH_MEMORY_PROBE 1635 bool "Enable sysfs memory/probe interface" 1636 depends on MEMORY_HOTPLUG 1637 help 1638 This option enables a sysfs memory/probe interface for testing. 1639 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1640 If you are unsure how to answer this question, answer N. 1641 1642config ARCH_PROC_KCORE_TEXT 1643 def_bool y 1644 depends on X86_64 && PROC_KCORE 1645 1646config ILLEGAL_POINTER_VALUE 1647 hex 1648 default 0 if X86_32 1649 default 0xdead000000000000 if X86_64 1650 1651config X86_PMEM_LEGACY_DEVICE 1652 bool 1653 1654config X86_PMEM_LEGACY 1655 tristate "Support non-standard NVDIMMs and ADR protected memory" 1656 depends on PHYS_ADDR_T_64BIT 1657 depends on BLK_DEV 1658 select X86_PMEM_LEGACY_DEVICE 1659 select NUMA_KEEP_MEMINFO if NUMA 1660 select LIBNVDIMM 1661 help 1662 Treat memory marked using the non-standard e820 type of 12 as used 1663 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1664 The kernel will offer these regions to the 'pmem' driver so 1665 they can be used for persistent storage. 1666 1667 Say Y if unsure. 1668 1669config HIGHPTE 1670 bool "Allocate 3rd-level pagetables from highmem" 1671 depends on HIGHMEM 1672 help 1673 The VM uses one page table entry for each page of physical memory. 1674 For systems with a lot of RAM, this can be wasteful of precious 1675 low memory. Setting this option will put user-space page table 1676 entries in high memory. 1677 1678config X86_CHECK_BIOS_CORRUPTION 1679 bool "Check for low memory corruption" 1680 help 1681 Periodically check for memory corruption in low memory, which 1682 is suspected to be caused by BIOS. Even when enabled in the 1683 configuration, it is disabled at runtime. Enable it by 1684 setting "memory_corruption_check=1" on the kernel command 1685 line. By default it scans the low 64k of memory every 60 1686 seconds; see the memory_corruption_check_size and 1687 memory_corruption_check_period parameters in 1688 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1689 1690 When enabled with the default parameters, this option has 1691 almost no overhead, as it reserves a relatively small amount 1692 of memory and scans it infrequently. It both detects corruption 1693 and prevents it from affecting the running system. 1694 1695 It is, however, intended as a diagnostic tool; if repeatable 1696 BIOS-originated corruption always affects the same memory, 1697 you can use memmap= to prevent the kernel from using that 1698 memory. 1699 1700config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1701 bool "Set the default setting of memory_corruption_check" 1702 depends on X86_CHECK_BIOS_CORRUPTION 1703 default y 1704 help 1705 Set whether the default state of memory_corruption_check is 1706 on or off. 1707 1708config MATH_EMULATION 1709 bool 1710 depends on MODIFY_LDT_SYSCALL 1711 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1712 help 1713 Linux can emulate a math coprocessor (used for floating point 1714 operations) if you don't have one. 486DX and Pentium processors have 1715 a math coprocessor built in, 486SX and 386 do not, unless you added 1716 a 487DX or 387, respectively. (The messages during boot time can 1717 give you some hints here ["man dmesg"].) Everyone needs either a 1718 coprocessor or this emulation. 1719 1720 If you don't have a math coprocessor, you need to say Y here; if you 1721 say Y here even though you have a coprocessor, the coprocessor will 1722 be used nevertheless. (This behavior can be changed with the kernel 1723 command line option "no387", which comes handy if your coprocessor 1724 is broken. Try "man bootparam" or see the documentation of your boot 1725 loader (lilo or loadlin) about how to pass options to the kernel at 1726 boot time.) This means that it is a good idea to say Y here if you 1727 intend to use this kernel on different machines. 1728 1729 More information about the internals of the Linux math coprocessor 1730 emulation can be found in <file:arch/x86/math-emu/README>. 1731 1732 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1733 kernel, it won't hurt. 1734 1735config MTRR 1736 def_bool y 1737 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1738 help 1739 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1740 the Memory Type Range Registers (MTRRs) may be used to control 1741 processor access to memory ranges. This is most useful if you have 1742 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1743 allows bus write transfers to be combined into a larger transfer 1744 before bursting over the PCI/AGP bus. This can increase performance 1745 of image write operations 2.5 times or more. Saying Y here creates a 1746 /proc/mtrr file which may be used to manipulate your processor's 1747 MTRRs. Typically the X server should use this. 1748 1749 This code has a reasonably generic interface so that similar 1750 control registers on other processors can be easily supported 1751 as well: 1752 1753 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1754 Registers (ARRs) which provide a similar functionality to MTRRs. For 1755 these, the ARRs are used to emulate the MTRRs. 1756 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1757 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1758 write-combining. All of these processors are supported by this code 1759 and it makes sense to say Y here if you have one of them. 1760 1761 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1762 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1763 can lead to all sorts of problems, so it's good to say Y here. 1764 1765 You can safely say Y even if your machine doesn't have MTRRs, you'll 1766 just add about 9 KB to your kernel. 1767 1768 See <file:Documentation/x86/mtrr.rst> for more information. 1769 1770config MTRR_SANITIZER 1771 def_bool y 1772 prompt "MTRR cleanup support" 1773 depends on MTRR 1774 help 1775 Convert MTRR layout from continuous to discrete, so X drivers can 1776 add writeback entries. 1777 1778 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1779 The largest mtrr entry size for a continuous block can be set with 1780 mtrr_chunk_size. 1781 1782 If unsure, say Y. 1783 1784config MTRR_SANITIZER_ENABLE_DEFAULT 1785 int "MTRR cleanup enable value (0-1)" 1786 range 0 1 1787 default "0" 1788 depends on MTRR_SANITIZER 1789 help 1790 Enable mtrr cleanup default value 1791 1792config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1793 int "MTRR cleanup spare reg num (0-7)" 1794 range 0 7 1795 default "1" 1796 depends on MTRR_SANITIZER 1797 help 1798 mtrr cleanup spare entries default, it can be changed via 1799 mtrr_spare_reg_nr=N on the kernel command line. 1800 1801config X86_PAT 1802 def_bool y 1803 prompt "x86 PAT support" if EXPERT 1804 depends on MTRR 1805 help 1806 Use PAT attributes to setup page level cache control. 1807 1808 PATs are the modern equivalents of MTRRs and are much more 1809 flexible than MTRRs. 1810 1811 Say N here if you see bootup problems (boot crash, boot hang, 1812 spontaneous reboots) or a non-working video driver. 1813 1814 If unsure, say Y. 1815 1816config ARCH_USES_PG_UNCACHED 1817 def_bool y 1818 depends on X86_PAT 1819 1820config ARCH_RANDOM 1821 def_bool y 1822 prompt "x86 architectural random number generator" if EXPERT 1823 help 1824 Enable the x86 architectural RDRAND instruction 1825 (Intel Bull Mountain technology) to generate random numbers. 1826 If supported, this is a high bandwidth, cryptographically 1827 secure hardware random number generator. 1828 1829config X86_SMAP 1830 def_bool y 1831 prompt "Supervisor Mode Access Prevention" if EXPERT 1832 help 1833 Supervisor Mode Access Prevention (SMAP) is a security 1834 feature in newer Intel processors. There is a small 1835 performance cost if this enabled and turned on; there is 1836 also a small increase in the kernel size if this is enabled. 1837 1838 If unsure, say Y. 1839 1840config X86_UMIP 1841 def_bool y 1842 prompt "User Mode Instruction Prevention" if EXPERT 1843 help 1844 User Mode Instruction Prevention (UMIP) is a security feature in 1845 some x86 processors. If enabled, a general protection fault is 1846 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1847 executed in user mode. These instructions unnecessarily expose 1848 information about the hardware state. 1849 1850 The vast majority of applications do not use these instructions. 1851 For the very few that do, software emulation is provided in 1852 specific cases in protected and virtual-8086 modes. Emulated 1853 results are dummy. 1854 1855config X86_INTEL_MEMORY_PROTECTION_KEYS 1856 prompt "Memory Protection Keys" 1857 def_bool y 1858 # Note: only available in 64-bit mode 1859 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1860 select ARCH_USES_HIGH_VMA_FLAGS 1861 select ARCH_HAS_PKEYS 1862 help 1863 Memory Protection Keys provides a mechanism for enforcing 1864 page-based protections, but without requiring modification of the 1865 page tables when an application changes protection domains. 1866 1867 For details, see Documentation/core-api/protection-keys.rst 1868 1869 If unsure, say y. 1870 1871choice 1872 prompt "TSX enable mode" 1873 depends on CPU_SUP_INTEL 1874 default X86_INTEL_TSX_MODE_OFF 1875 help 1876 Intel's TSX (Transactional Synchronization Extensions) feature 1877 allows to optimize locking protocols through lock elision which 1878 can lead to a noticeable performance boost. 1879 1880 On the other hand it has been shown that TSX can be exploited 1881 to form side channel attacks (e.g. TAA) and chances are there 1882 will be more of those attacks discovered in the future. 1883 1884 Therefore TSX is not enabled by default (aka tsx=off). An admin 1885 might override this decision by tsx=on the command line parameter. 1886 Even with TSX enabled, the kernel will attempt to enable the best 1887 possible TAA mitigation setting depending on the microcode available 1888 for the particular machine. 1889 1890 This option allows to set the default tsx mode between tsx=on, =off 1891 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1892 details. 1893 1894 Say off if not sure, auto if TSX is in use but it should be used on safe 1895 platforms or on if TSX is in use and the security aspect of tsx is not 1896 relevant. 1897 1898config X86_INTEL_TSX_MODE_OFF 1899 bool "off" 1900 help 1901 TSX is disabled if possible - equals to tsx=off command line parameter. 1902 1903config X86_INTEL_TSX_MODE_ON 1904 bool "on" 1905 help 1906 TSX is always enabled on TSX capable HW - equals the tsx=on command 1907 line parameter. 1908 1909config X86_INTEL_TSX_MODE_AUTO 1910 bool "auto" 1911 help 1912 TSX is enabled on TSX capable HW that is believed to be safe against 1913 side channel attacks- equals the tsx=auto command line parameter. 1914endchoice 1915 1916config X86_SGX 1917 bool "Software Guard eXtensions (SGX)" 1918 depends on X86_64 && CPU_SUP_INTEL 1919 depends on CRYPTO=y 1920 depends on CRYPTO_SHA256=y 1921 select SRCU 1922 select MMU_NOTIFIER 1923 select NUMA_KEEP_MEMINFO if NUMA 1924 help 1925 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1926 that can be used by applications to set aside private regions of code 1927 and data, referred to as enclaves. An enclave's private memory can 1928 only be accessed by code running within the enclave. Accesses from 1929 outside the enclave, including other enclaves, are disallowed by 1930 hardware. 1931 1932 If unsure, say N. 1933 1934config EFI 1935 bool "EFI runtime service support" 1936 depends on ACPI 1937 select UCS2_STRING 1938 select EFI_RUNTIME_WRAPPERS 1939 help 1940 This enables the kernel to use EFI runtime services that are 1941 available (such as the EFI variable services). 1942 1943 This option is only useful on systems that have EFI firmware. 1944 In addition, you should use the latest ELILO loader available 1945 at <http://elilo.sourceforge.net> in order to take advantage 1946 of EFI runtime services. However, even with this option, the 1947 resultant kernel should continue to boot on existing non-EFI 1948 platforms. 1949 1950config EFI_STUB 1951 bool "EFI stub support" 1952 depends on EFI && !X86_USE_3DNOW 1953 depends on $(cc-option,-mabi=ms) || X86_32 1954 select RELOCATABLE 1955 help 1956 This kernel feature allows a bzImage to be loaded directly 1957 by EFI firmware without the use of a bootloader. 1958 1959 See Documentation/admin-guide/efi-stub.rst for more information. 1960 1961config EFI_MIXED 1962 bool "EFI mixed-mode support" 1963 depends on EFI_STUB && X86_64 1964 help 1965 Enabling this feature allows a 64-bit kernel to be booted 1966 on a 32-bit firmware, provided that your CPU supports 64-bit 1967 mode. 1968 1969 Note that it is not possible to boot a mixed-mode enabled 1970 kernel via the EFI boot stub - a bootloader that supports 1971 the EFI handover protocol must be used. 1972 1973 If unsure, say N. 1974 1975source "kernel/Kconfig.hz" 1976 1977config KEXEC 1978 bool "kexec system call" 1979 select KEXEC_CORE 1980 help 1981 kexec is a system call that implements the ability to shutdown your 1982 current kernel, and to start another kernel. It is like a reboot 1983 but it is independent of the system firmware. And like a reboot 1984 you can start any kernel with it, not just Linux. 1985 1986 The name comes from the similarity to the exec system call. 1987 1988 It is an ongoing process to be certain the hardware in a machine 1989 is properly shutdown, so do not be surprised if this code does not 1990 initially work for you. As of this writing the exact hardware 1991 interface is strongly in flux, so no good recommendation can be 1992 made. 1993 1994config KEXEC_FILE 1995 bool "kexec file based system call" 1996 select KEXEC_CORE 1997 select BUILD_BIN2C 1998 depends on X86_64 1999 depends on CRYPTO=y 2000 depends on CRYPTO_SHA256=y 2001 help 2002 This is new version of kexec system call. This system call is 2003 file based and takes file descriptors as system call argument 2004 for kernel and initramfs as opposed to list of segments as 2005 accepted by previous system call. 2006 2007config ARCH_HAS_KEXEC_PURGATORY 2008 def_bool KEXEC_FILE 2009 2010config KEXEC_SIG 2011 bool "Verify kernel signature during kexec_file_load() syscall" 2012 depends on KEXEC_FILE 2013 help 2014 2015 This option makes the kexec_file_load() syscall check for a valid 2016 signature of the kernel image. The image can still be loaded without 2017 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2018 there's a signature that we can check, then it must be valid. 2019 2020 In addition to this option, you need to enable signature 2021 verification for the corresponding kernel image type being 2022 loaded in order for this to work. 2023 2024config KEXEC_SIG_FORCE 2025 bool "Require a valid signature in kexec_file_load() syscall" 2026 depends on KEXEC_SIG 2027 help 2028 This option makes kernel signature verification mandatory for 2029 the kexec_file_load() syscall. 2030 2031config KEXEC_BZIMAGE_VERIFY_SIG 2032 bool "Enable bzImage signature verification support" 2033 depends on KEXEC_SIG 2034 depends on SIGNED_PE_FILE_VERIFICATION 2035 select SYSTEM_TRUSTED_KEYRING 2036 help 2037 Enable bzImage signature verification support. 2038 2039config CRASH_DUMP 2040 bool "kernel crash dumps" 2041 depends on X86_64 || (X86_32 && HIGHMEM) 2042 help 2043 Generate crash dump after being started by kexec. 2044 This should be normally only set in special crash dump kernels 2045 which are loaded in the main kernel with kexec-tools into 2046 a specially reserved region and then later executed after 2047 a crash by kdump/kexec. The crash dump kernel must be compiled 2048 to a memory address not used by the main kernel or BIOS using 2049 PHYSICAL_START, or it must be built as a relocatable image 2050 (CONFIG_RELOCATABLE=y). 2051 For more details see Documentation/admin-guide/kdump/kdump.rst 2052 2053config KEXEC_JUMP 2054 bool "kexec jump" 2055 depends on KEXEC && HIBERNATION 2056 help 2057 Jump between original kernel and kexeced kernel and invoke 2058 code in physical address mode via KEXEC 2059 2060config PHYSICAL_START 2061 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2062 default "0x1000000" 2063 help 2064 This gives the physical address where the kernel is loaded. 2065 2066 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2067 bzImage will decompress itself to above physical address and 2068 run from there. Otherwise, bzImage will run from the address where 2069 it has been loaded by the boot loader and will ignore above physical 2070 address. 2071 2072 In normal kdump cases one does not have to set/change this option 2073 as now bzImage can be compiled as a completely relocatable image 2074 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2075 address. This option is mainly useful for the folks who don't want 2076 to use a bzImage for capturing the crash dump and want to use a 2077 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2078 to be specifically compiled to run from a specific memory area 2079 (normally a reserved region) and this option comes handy. 2080 2081 So if you are using bzImage for capturing the crash dump, 2082 leave the value here unchanged to 0x1000000 and set 2083 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2084 for capturing the crash dump change this value to start of 2085 the reserved region. In other words, it can be set based on 2086 the "X" value as specified in the "crashkernel=YM@XM" 2087 command line boot parameter passed to the panic-ed 2088 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2089 for more details about crash dumps. 2090 2091 Usage of bzImage for capturing the crash dump is recommended as 2092 one does not have to build two kernels. Same kernel can be used 2093 as production kernel and capture kernel. Above option should have 2094 gone away after relocatable bzImage support is introduced. But it 2095 is present because there are users out there who continue to use 2096 vmlinux for dump capture. This option should go away down the 2097 line. 2098 2099 Don't change this unless you know what you are doing. 2100 2101config RELOCATABLE 2102 bool "Build a relocatable kernel" 2103 default y 2104 help 2105 This builds a kernel image that retains relocation information 2106 so it can be loaded someplace besides the default 1MB. 2107 The relocations tend to make the kernel binary about 10% larger, 2108 but are discarded at runtime. 2109 2110 One use is for the kexec on panic case where the recovery kernel 2111 must live at a different physical address than the primary 2112 kernel. 2113 2114 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2115 it has been loaded at and the compile time physical address 2116 (CONFIG_PHYSICAL_START) is used as the minimum location. 2117 2118config RANDOMIZE_BASE 2119 bool "Randomize the address of the kernel image (KASLR)" 2120 depends on RELOCATABLE 2121 default y 2122 help 2123 In support of Kernel Address Space Layout Randomization (KASLR), 2124 this randomizes the physical address at which the kernel image 2125 is decompressed and the virtual address where the kernel 2126 image is mapped, as a security feature that deters exploit 2127 attempts relying on knowledge of the location of kernel 2128 code internals. 2129 2130 On 64-bit, the kernel physical and virtual addresses are 2131 randomized separately. The physical address will be anywhere 2132 between 16MB and the top of physical memory (up to 64TB). The 2133 virtual address will be randomized from 16MB up to 1GB (9 bits 2134 of entropy). Note that this also reduces the memory space 2135 available to kernel modules from 1.5GB to 1GB. 2136 2137 On 32-bit, the kernel physical and virtual addresses are 2138 randomized together. They will be randomized from 16MB up to 2139 512MB (8 bits of entropy). 2140 2141 Entropy is generated using the RDRAND instruction if it is 2142 supported. If RDTSC is supported, its value is mixed into 2143 the entropy pool as well. If neither RDRAND nor RDTSC are 2144 supported, then entropy is read from the i8254 timer. The 2145 usable entropy is limited by the kernel being built using 2146 2GB addressing, and that PHYSICAL_ALIGN must be at a 2147 minimum of 2MB. As a result, only 10 bits of entropy are 2148 theoretically possible, but the implementations are further 2149 limited due to memory layouts. 2150 2151 If unsure, say Y. 2152 2153# Relocation on x86 needs some additional build support 2154config X86_NEED_RELOCS 2155 def_bool y 2156 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2157 2158config PHYSICAL_ALIGN 2159 hex "Alignment value to which kernel should be aligned" 2160 default "0x200000" 2161 range 0x2000 0x1000000 if X86_32 2162 range 0x200000 0x1000000 if X86_64 2163 help 2164 This value puts the alignment restrictions on physical address 2165 where kernel is loaded and run from. Kernel is compiled for an 2166 address which meets above alignment restriction. 2167 2168 If bootloader loads the kernel at a non-aligned address and 2169 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2170 address aligned to above value and run from there. 2171 2172 If bootloader loads the kernel at a non-aligned address and 2173 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2174 load address and decompress itself to the address it has been 2175 compiled for and run from there. The address for which kernel is 2176 compiled already meets above alignment restrictions. Hence the 2177 end result is that kernel runs from a physical address meeting 2178 above alignment restrictions. 2179 2180 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2181 this value must be a multiple of 0x200000. 2182 2183 Don't change this unless you know what you are doing. 2184 2185config DYNAMIC_MEMORY_LAYOUT 2186 bool 2187 help 2188 This option makes base addresses of vmalloc and vmemmap as well as 2189 __PAGE_OFFSET movable during boot. 2190 2191config RANDOMIZE_MEMORY 2192 bool "Randomize the kernel memory sections" 2193 depends on X86_64 2194 depends on RANDOMIZE_BASE 2195 select DYNAMIC_MEMORY_LAYOUT 2196 default RANDOMIZE_BASE 2197 help 2198 Randomizes the base virtual address of kernel memory sections 2199 (physical memory mapping, vmalloc & vmemmap). This security feature 2200 makes exploits relying on predictable memory locations less reliable. 2201 2202 The order of allocations remains unchanged. Entropy is generated in 2203 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2204 configuration have in average 30,000 different possible virtual 2205 addresses for each memory section. 2206 2207 If unsure, say Y. 2208 2209config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2210 hex "Physical memory mapping padding" if EXPERT 2211 depends on RANDOMIZE_MEMORY 2212 default "0xa" if MEMORY_HOTPLUG 2213 default "0x0" 2214 range 0x1 0x40 if MEMORY_HOTPLUG 2215 range 0x0 0x40 2216 help 2217 Define the padding in terabytes added to the existing physical 2218 memory size during kernel memory randomization. It is useful 2219 for memory hotplug support but reduces the entropy available for 2220 address randomization. 2221 2222 If unsure, leave at the default value. 2223 2224config HOTPLUG_CPU 2225 def_bool y 2226 depends on SMP 2227 2228config BOOTPARAM_HOTPLUG_CPU0 2229 bool "Set default setting of cpu0_hotpluggable" 2230 depends on HOTPLUG_CPU 2231 help 2232 Set whether default state of cpu0_hotpluggable is on or off. 2233 2234 Say Y here to enable CPU0 hotplug by default. If this switch 2235 is turned on, there is no need to give cpu0_hotplug kernel 2236 parameter and the CPU0 hotplug feature is enabled by default. 2237 2238 Please note: there are two known CPU0 dependencies if you want 2239 to enable the CPU0 hotplug feature either by this switch or by 2240 cpu0_hotplug kernel parameter. 2241 2242 First, resume from hibernate or suspend always starts from CPU0. 2243 So hibernate and suspend are prevented if CPU0 is offline. 2244 2245 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2246 offline if any interrupt can not migrate out of CPU0. There may 2247 be other CPU0 dependencies. 2248 2249 Please make sure the dependencies are under your control before 2250 you enable this feature. 2251 2252 Say N if you don't want to enable CPU0 hotplug feature by default. 2253 You still can enable the CPU0 hotplug feature at boot by kernel 2254 parameter cpu0_hotplug. 2255 2256config DEBUG_HOTPLUG_CPU0 2257 def_bool n 2258 prompt "Debug CPU0 hotplug" 2259 depends on HOTPLUG_CPU 2260 help 2261 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2262 soon as possible and boots up userspace with CPU0 offlined. User 2263 can online CPU0 back after boot time. 2264 2265 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2266 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2267 compilation or giving cpu0_hotplug kernel parameter at boot. 2268 2269 If unsure, say N. 2270 2271config COMPAT_VDSO 2272 def_bool n 2273 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2274 depends on COMPAT_32 2275 help 2276 Certain buggy versions of glibc will crash if they are 2277 presented with a 32-bit vDSO that is not mapped at the address 2278 indicated in its segment table. 2279 2280 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2281 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2282 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2283 the only released version with the bug, but OpenSUSE 9 2284 contains a buggy "glibc 2.3.2". 2285 2286 The symptom of the bug is that everything crashes on startup, saying: 2287 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2288 2289 Saying Y here changes the default value of the vdso32 boot 2290 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2291 This works around the glibc bug but hurts performance. 2292 2293 If unsure, say N: if you are compiling your own kernel, you 2294 are unlikely to be using a buggy version of glibc. 2295 2296choice 2297 prompt "vsyscall table for legacy applications" 2298 depends on X86_64 2299 default LEGACY_VSYSCALL_XONLY 2300 help 2301 Legacy user code that does not know how to find the vDSO expects 2302 to be able to issue three syscalls by calling fixed addresses in 2303 kernel space. Since this location is not randomized with ASLR, 2304 it can be used to assist security vulnerability exploitation. 2305 2306 This setting can be changed at boot time via the kernel command 2307 line parameter vsyscall=[emulate|xonly|none]. 2308 2309 On a system with recent enough glibc (2.14 or newer) and no 2310 static binaries, you can say None without a performance penalty 2311 to improve security. 2312 2313 If unsure, select "Emulate execution only". 2314 2315 config LEGACY_VSYSCALL_EMULATE 2316 bool "Full emulation" 2317 help 2318 The kernel traps and emulates calls into the fixed vsyscall 2319 address mapping. This makes the mapping non-executable, but 2320 it still contains readable known contents, which could be 2321 used in certain rare security vulnerability exploits. This 2322 configuration is recommended when using legacy userspace 2323 that still uses vsyscalls along with legacy binary 2324 instrumentation tools that require code to be readable. 2325 2326 An example of this type of legacy userspace is running 2327 Pin on an old binary that still uses vsyscalls. 2328 2329 config LEGACY_VSYSCALL_XONLY 2330 bool "Emulate execution only" 2331 help 2332 The kernel traps and emulates calls into the fixed vsyscall 2333 address mapping and does not allow reads. This 2334 configuration is recommended when userspace might use the 2335 legacy vsyscall area but support for legacy binary 2336 instrumentation of legacy code is not needed. It mitigates 2337 certain uses of the vsyscall area as an ASLR-bypassing 2338 buffer. 2339 2340 config LEGACY_VSYSCALL_NONE 2341 bool "None" 2342 help 2343 There will be no vsyscall mapping at all. This will 2344 eliminate any risk of ASLR bypass due to the vsyscall 2345 fixed address mapping. Attempts to use the vsyscalls 2346 will be reported to dmesg, so that either old or 2347 malicious userspace programs can be identified. 2348 2349endchoice 2350 2351config CMDLINE_BOOL 2352 bool "Built-in kernel command line" 2353 help 2354 Allow for specifying boot arguments to the kernel at 2355 build time. On some systems (e.g. embedded ones), it is 2356 necessary or convenient to provide some or all of the 2357 kernel boot arguments with the kernel itself (that is, 2358 to not rely on the boot loader to provide them.) 2359 2360 To compile command line arguments into the kernel, 2361 set this option to 'Y', then fill in the 2362 boot arguments in CONFIG_CMDLINE. 2363 2364 Systems with fully functional boot loaders (i.e. non-embedded) 2365 should leave this option set to 'N'. 2366 2367config CMDLINE 2368 string "Built-in kernel command string" 2369 depends on CMDLINE_BOOL 2370 default "" 2371 help 2372 Enter arguments here that should be compiled into the kernel 2373 image and used at boot time. If the boot loader provides a 2374 command line at boot time, it is appended to this string to 2375 form the full kernel command line, when the system boots. 2376 2377 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2378 change this behavior. 2379 2380 In most cases, the command line (whether built-in or provided 2381 by the boot loader) should specify the device for the root 2382 file system. 2383 2384config CMDLINE_OVERRIDE 2385 bool "Built-in command line overrides boot loader arguments" 2386 depends on CMDLINE_BOOL && CMDLINE != "" 2387 help 2388 Set this option to 'Y' to have the kernel ignore the boot loader 2389 command line, and use ONLY the built-in command line. 2390 2391 This is used to work around broken boot loaders. This should 2392 be set to 'N' under normal conditions. 2393 2394config MODIFY_LDT_SYSCALL 2395 bool "Enable the LDT (local descriptor table)" if EXPERT 2396 default y 2397 help 2398 Linux can allow user programs to install a per-process x86 2399 Local Descriptor Table (LDT) using the modify_ldt(2) system 2400 call. This is required to run 16-bit or segmented code such as 2401 DOSEMU or some Wine programs. It is also used by some very old 2402 threading libraries. 2403 2404 Enabling this feature adds a small amount of overhead to 2405 context switches and increases the low-level kernel attack 2406 surface. Disabling it removes the modify_ldt(2) system call. 2407 2408 Saying 'N' here may make sense for embedded or server kernels. 2409 2410config STRICT_SIGALTSTACK_SIZE 2411 bool "Enforce strict size checking for sigaltstack" 2412 depends on DYNAMIC_SIGFRAME 2413 help 2414 For historical reasons MINSIGSTKSZ is a constant which became 2415 already too small with AVX512 support. Add a mechanism to 2416 enforce strict checking of the sigaltstack size against the 2417 real size of the FPU frame. This option enables the check 2418 by default. It can also be controlled via the kernel command 2419 line option 'strict_sas_size' independent of this config 2420 switch. Enabling it might break existing applications which 2421 allocate a too small sigaltstack but 'work' because they 2422 never get a signal delivered. 2423 2424 Say 'N' unless you want to really enforce this check. 2425 2426source "kernel/livepatch/Kconfig" 2427 2428endmenu 2429 2430config ARCH_HAS_ADD_PAGES 2431 def_bool y 2432 depends on ARCH_ENABLE_MEMORY_HOTPLUG 2433 2434config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 2435 def_bool y 2436 2437config USE_PERCPU_NUMA_NODE_ID 2438 def_bool y 2439 depends on NUMA 2440 2441menu "Power management and ACPI options" 2442 2443config ARCH_HIBERNATION_HEADER 2444 def_bool y 2445 depends on HIBERNATION 2446 2447source "kernel/power/Kconfig" 2448 2449source "drivers/acpi/Kconfig" 2450 2451config X86_APM_BOOT 2452 def_bool y 2453 depends on APM 2454 2455menuconfig APM 2456 tristate "APM (Advanced Power Management) BIOS support" 2457 depends on X86_32 && PM_SLEEP 2458 help 2459 APM is a BIOS specification for saving power using several different 2460 techniques. This is mostly useful for battery powered laptops with 2461 APM compliant BIOSes. If you say Y here, the system time will be 2462 reset after a RESUME operation, the /proc/apm device will provide 2463 battery status information, and user-space programs will receive 2464 notification of APM "events" (e.g. battery status change). 2465 2466 If you select "Y" here, you can disable actual use of the APM 2467 BIOS by passing the "apm=off" option to the kernel at boot time. 2468 2469 Note that the APM support is almost completely disabled for 2470 machines with more than one CPU. 2471 2472 In order to use APM, you will need supporting software. For location 2473 and more information, read <file:Documentation/power/apm-acpi.rst> 2474 and the Battery Powered Linux mini-HOWTO, available from 2475 <http://www.tldp.org/docs.html#howto>. 2476 2477 This driver does not spin down disk drives (see the hdparm(8) 2478 manpage ("man 8 hdparm") for that), and it doesn't turn off 2479 VESA-compliant "green" monitors. 2480 2481 This driver does not support the TI 4000M TravelMate and the ACER 2482 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2483 desktop machines also don't have compliant BIOSes, and this driver 2484 may cause those machines to panic during the boot phase. 2485 2486 Generally, if you don't have a battery in your machine, there isn't 2487 much point in using this driver and you should say N. If you get 2488 random kernel OOPSes or reboots that don't seem to be related to 2489 anything, try disabling/enabling this option (or disabling/enabling 2490 APM in your BIOS). 2491 2492 Some other things you should try when experiencing seemingly random, 2493 "weird" problems: 2494 2495 1) make sure that you have enough swap space and that it is 2496 enabled. 2497 2) pass the "no-hlt" option to the kernel 2498 3) switch on floating point emulation in the kernel and pass 2499 the "no387" option to the kernel 2500 4) pass the "floppy=nodma" option to the kernel 2501 5) pass the "mem=4M" option to the kernel (thereby disabling 2502 all but the first 4 MB of RAM) 2503 6) make sure that the CPU is not over clocked. 2504 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2505 8) disable the cache from your BIOS settings 2506 9) install a fan for the video card or exchange video RAM 2507 10) install a better fan for the CPU 2508 11) exchange RAM chips 2509 12) exchange the motherboard. 2510 2511 To compile this driver as a module, choose M here: the 2512 module will be called apm. 2513 2514if APM 2515 2516config APM_IGNORE_USER_SUSPEND 2517 bool "Ignore USER SUSPEND" 2518 help 2519 This option will ignore USER SUSPEND requests. On machines with a 2520 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2521 series notebooks, it is necessary to say Y because of a BIOS bug. 2522 2523config APM_DO_ENABLE 2524 bool "Enable PM at boot time" 2525 help 2526 Enable APM features at boot time. From page 36 of the APM BIOS 2527 specification: "When disabled, the APM BIOS does not automatically 2528 power manage devices, enter the Standby State, enter the Suspend 2529 State, or take power saving steps in response to CPU Idle calls." 2530 This driver will make CPU Idle calls when Linux is idle (unless this 2531 feature is turned off -- see "Do CPU IDLE calls", below). This 2532 should always save battery power, but more complicated APM features 2533 will be dependent on your BIOS implementation. You may need to turn 2534 this option off if your computer hangs at boot time when using APM 2535 support, or if it beeps continuously instead of suspending. Turn 2536 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2537 T400CDT. This is off by default since most machines do fine without 2538 this feature. 2539 2540config APM_CPU_IDLE 2541 depends on CPU_IDLE 2542 bool "Make CPU Idle calls when idle" 2543 help 2544 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2545 On some machines, this can activate improved power savings, such as 2546 a slowed CPU clock rate, when the machine is idle. These idle calls 2547 are made after the idle loop has run for some length of time (e.g., 2548 333 mS). On some machines, this will cause a hang at boot time or 2549 whenever the CPU becomes idle. (On machines with more than one CPU, 2550 this option does nothing.) 2551 2552config APM_DISPLAY_BLANK 2553 bool "Enable console blanking using APM" 2554 help 2555 Enable console blanking using the APM. Some laptops can use this to 2556 turn off the LCD backlight when the screen blanker of the Linux 2557 virtual console blanks the screen. Note that this is only used by 2558 the virtual console screen blanker, and won't turn off the backlight 2559 when using the X Window system. This also doesn't have anything to 2560 do with your VESA-compliant power-saving monitor. Further, this 2561 option doesn't work for all laptops -- it might not turn off your 2562 backlight at all, or it might print a lot of errors to the console, 2563 especially if you are using gpm. 2564 2565config APM_ALLOW_INTS 2566 bool "Allow interrupts during APM BIOS calls" 2567 help 2568 Normally we disable external interrupts while we are making calls to 2569 the APM BIOS as a measure to lessen the effects of a badly behaving 2570 BIOS implementation. The BIOS should reenable interrupts if it 2571 needs to. Unfortunately, some BIOSes do not -- especially those in 2572 many of the newer IBM Thinkpads. If you experience hangs when you 2573 suspend, try setting this to Y. Otherwise, say N. 2574 2575endif # APM 2576 2577source "drivers/cpufreq/Kconfig" 2578 2579source "drivers/cpuidle/Kconfig" 2580 2581source "drivers/idle/Kconfig" 2582 2583endmenu 2584 2585 2586menu "Bus options (PCI etc.)" 2587 2588choice 2589 prompt "PCI access mode" 2590 depends on X86_32 && PCI 2591 default PCI_GOANY 2592 help 2593 On PCI systems, the BIOS can be used to detect the PCI devices and 2594 determine their configuration. However, some old PCI motherboards 2595 have BIOS bugs and may crash if this is done. Also, some embedded 2596 PCI-based systems don't have any BIOS at all. Linux can also try to 2597 detect the PCI hardware directly without using the BIOS. 2598 2599 With this option, you can specify how Linux should detect the 2600 PCI devices. If you choose "BIOS", the BIOS will be used, 2601 if you choose "Direct", the BIOS won't be used, and if you 2602 choose "MMConfig", then PCI Express MMCONFIG will be used. 2603 If you choose "Any", the kernel will try MMCONFIG, then the 2604 direct access method and falls back to the BIOS if that doesn't 2605 work. If unsure, go with the default, which is "Any". 2606 2607config PCI_GOBIOS 2608 bool "BIOS" 2609 2610config PCI_GOMMCONFIG 2611 bool "MMConfig" 2612 2613config PCI_GODIRECT 2614 bool "Direct" 2615 2616config PCI_GOOLPC 2617 bool "OLPC XO-1" 2618 depends on OLPC 2619 2620config PCI_GOANY 2621 bool "Any" 2622 2623endchoice 2624 2625config PCI_BIOS 2626 def_bool y 2627 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2628 2629# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2630config PCI_DIRECT 2631 def_bool y 2632 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2633 2634config PCI_MMCONFIG 2635 bool "Support mmconfig PCI config space access" if X86_64 2636 default y 2637 depends on PCI && (ACPI || JAILHOUSE_GUEST) 2638 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2639 2640config PCI_OLPC 2641 def_bool y 2642 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2643 2644config PCI_XEN 2645 def_bool y 2646 depends on PCI && XEN 2647 2648config MMCONF_FAM10H 2649 def_bool y 2650 depends on X86_64 && PCI_MMCONFIG && ACPI 2651 2652config PCI_CNB20LE_QUIRK 2653 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2654 depends on PCI 2655 help 2656 Read the PCI windows out of the CNB20LE host bridge. This allows 2657 PCI hotplug to work on systems with the CNB20LE chipset which do 2658 not have ACPI. 2659 2660 There's no public spec for this chipset, and this functionality 2661 is known to be incomplete. 2662 2663 You should say N unless you know you need this. 2664 2665config ISA_BUS 2666 bool "ISA bus support on modern systems" if EXPERT 2667 help 2668 Expose ISA bus device drivers and options available for selection and 2669 configuration. Enable this option if your target machine has an ISA 2670 bus. ISA is an older system, displaced by PCI and newer bus 2671 architectures -- if your target machine is modern, it probably does 2672 not have an ISA bus. 2673 2674 If unsure, say N. 2675 2676# x86_64 have no ISA slots, but can have ISA-style DMA. 2677config ISA_DMA_API 2678 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2679 default y 2680 help 2681 Enables ISA-style DMA support for devices requiring such controllers. 2682 If unsure, say Y. 2683 2684if X86_32 2685 2686config ISA 2687 bool "ISA support" 2688 help 2689 Find out whether you have ISA slots on your motherboard. ISA is the 2690 name of a bus system, i.e. the way the CPU talks to the other stuff 2691 inside your box. Other bus systems are PCI, EISA, MicroChannel 2692 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2693 newer boards don't support it. If you have ISA, say Y, otherwise N. 2694 2695config SCx200 2696 tristate "NatSemi SCx200 support" 2697 help 2698 This provides basic support for National Semiconductor's 2699 (now AMD's) Geode processors. The driver probes for the 2700 PCI-IDs of several on-chip devices, so its a good dependency 2701 for other scx200_* drivers. 2702 2703 If compiled as a module, the driver is named scx200. 2704 2705config SCx200HR_TIMER 2706 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2707 depends on SCx200 2708 default y 2709 help 2710 This driver provides a clocksource built upon the on-chip 2711 27MHz high-resolution timer. Its also a workaround for 2712 NSC Geode SC-1100's buggy TSC, which loses time when the 2713 processor goes idle (as is done by the scheduler). The 2714 other workaround is idle=poll boot option. 2715 2716config OLPC 2717 bool "One Laptop Per Child support" 2718 depends on !X86_PAE 2719 select GPIOLIB 2720 select OF 2721 select OF_PROMTREE 2722 select IRQ_DOMAIN 2723 select OLPC_EC 2724 help 2725 Add support for detecting the unique features of the OLPC 2726 XO hardware. 2727 2728config OLPC_XO1_PM 2729 bool "OLPC XO-1 Power Management" 2730 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2731 help 2732 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2733 2734config OLPC_XO1_RTC 2735 bool "OLPC XO-1 Real Time Clock" 2736 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2737 help 2738 Add support for the XO-1 real time clock, which can be used as a 2739 programmable wakeup source. 2740 2741config OLPC_XO1_SCI 2742 bool "OLPC XO-1 SCI extras" 2743 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2744 depends on INPUT=y 2745 select POWER_SUPPLY 2746 help 2747 Add support for SCI-based features of the OLPC XO-1 laptop: 2748 - EC-driven system wakeups 2749 - Power button 2750 - Ebook switch 2751 - Lid switch 2752 - AC adapter status updates 2753 - Battery status updates 2754 2755config OLPC_XO15_SCI 2756 bool "OLPC XO-1.5 SCI extras" 2757 depends on OLPC && ACPI 2758 select POWER_SUPPLY 2759 help 2760 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2761 - EC-driven system wakeups 2762 - AC adapter status updates 2763 - Battery status updates 2764 2765config ALIX 2766 bool "PCEngines ALIX System Support (LED setup)" 2767 select GPIOLIB 2768 help 2769 This option enables system support for the PCEngines ALIX. 2770 At present this just sets up LEDs for GPIO control on 2771 ALIX2/3/6 boards. However, other system specific setup should 2772 get added here. 2773 2774 Note: You must still enable the drivers for GPIO and LED support 2775 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2776 2777 Note: You have to set alix.force=1 for boards with Award BIOS. 2778 2779config NET5501 2780 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2781 select GPIOLIB 2782 help 2783 This option enables system support for the Soekris Engineering net5501. 2784 2785config GEOS 2786 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2787 select GPIOLIB 2788 depends on DMI 2789 help 2790 This option enables system support for the Traverse Technologies GEOS. 2791 2792config TS5500 2793 bool "Technologic Systems TS-5500 platform support" 2794 depends on MELAN 2795 select CHECK_SIGNATURE 2796 select NEW_LEDS 2797 select LEDS_CLASS 2798 help 2799 This option enables system support for the Technologic Systems TS-5500. 2800 2801endif # X86_32 2802 2803config AMD_NB 2804 def_bool y 2805 depends on CPU_SUP_AMD && PCI 2806 2807endmenu 2808 2809 2810menu "Binary Emulations" 2811 2812config IA32_EMULATION 2813 bool "IA32 Emulation" 2814 depends on X86_64 2815 select ARCH_WANT_OLD_COMPAT_IPC 2816 select BINFMT_ELF 2817 select COMPAT_OLD_SIGACTION 2818 help 2819 Include code to run legacy 32-bit programs under a 2820 64-bit kernel. You should likely turn this on, unless you're 2821 100% sure that you don't have any 32-bit programs left. 2822 2823config IA32_AOUT 2824 tristate "IA32 a.out support" 2825 depends on IA32_EMULATION 2826 depends on BROKEN 2827 help 2828 Support old a.out binaries in the 32bit emulation. 2829 2830config X86_X32 2831 bool "x32 ABI for 64-bit mode" 2832 depends on X86_64 2833 help 2834 Include code to run binaries for the x32 native 32-bit ABI 2835 for 64-bit processors. An x32 process gets access to the 2836 full 64-bit register file and wide data path while leaving 2837 pointers at 32 bits for smaller memory footprint. 2838 2839 You will need a recent binutils (2.22 or later) with 2840 elf32_x86_64 support enabled to compile a kernel with this 2841 option set. 2842 2843config COMPAT_32 2844 def_bool y 2845 depends on IA32_EMULATION || X86_32 2846 select HAVE_UID16 2847 select OLD_SIGSUSPEND3 2848 2849config COMPAT 2850 def_bool y 2851 depends on IA32_EMULATION || X86_X32 2852 2853if COMPAT 2854config COMPAT_FOR_U64_ALIGNMENT 2855 def_bool y 2856 2857config SYSVIPC_COMPAT 2858 def_bool y 2859 depends on SYSVIPC 2860endif 2861 2862endmenu 2863 2864 2865config HAVE_ATOMIC_IOMAP 2866 def_bool y 2867 depends on X86_32 2868 2869source "arch/x86/kvm/Kconfig" 2870 2871source "arch/x86/Kconfig.assembler" 2872