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