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