1# SPDX-License-Identifier: GPL-2.0 2# Select 32 or 64 bit 3config 64BIT 4 bool "64-bit kernel" if "$(ARCH)" = "x86" 5 default "$(ARCH)" != "i386" 6 help 7 Say yes to build a 64-bit kernel - formerly known as x86_64 8 Say no to build a 32-bit kernel - formerly known as i386 9 10config X86_32 11 def_bool y 12 depends on !64BIT 13 # Options that are inherently 32-bit kernel only: 14 select ARCH_WANT_IPC_PARSE_VERSION 15 select CLKSRC_I8253 16 select CLONE_BACKWARDS 17 select GENERIC_VDSO_32 18 select HAVE_DEBUG_STACKOVERFLOW 19 select KMAP_LOCAL 20 select MODULES_USE_ELF_REL 21 select OLD_SIGACTION 22 select ARCH_SPLIT_ARG64 23 24config X86_64 25 def_bool y 26 depends on 64BIT 27 # Options that are inherently 64-bit kernel only: 28 select ARCH_HAS_GIGANTIC_PAGE 29 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 30 select ARCH_USE_CMPXCHG_LOCKREF 31 select HAVE_ARCH_SOFT_DIRTY 32 select MODULES_USE_ELF_RELA 33 select NEED_DMA_MAP_STATE 34 select SWIOTLB 35 select ARCH_HAS_ELFCORE_COMPAT 36 select ZONE_DMA32 37 38config FORCE_DYNAMIC_FTRACE 39 def_bool y 40 depends on X86_32 41 depends on FUNCTION_TRACER 42 select DYNAMIC_FTRACE 43 help 44 We keep the static function tracing (!DYNAMIC_FTRACE) around 45 in order to test the non static function tracing in the 46 generic code, as other architectures still use it. But we 47 only need to keep it around for x86_64. No need to keep it 48 for x86_32. For x86_32, force DYNAMIC_FTRACE. 49# 50# Arch settings 51# 52# ( Note that options that are marked 'if X86_64' could in principle be 53# ported to 32-bit as well. ) 54# 55config X86 56 def_bool y 57 # 58 # Note: keep this list sorted alphabetically 59 # 60 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 61 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 62 select ARCH_32BIT_OFF_T if X86_32 63 select ARCH_CLOCKSOURCE_INIT 64 select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 65 select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION 66 select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64 || (X86_32 && HIGHMEM) 67 select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG 68 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE) 69 select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE 70 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 71 select ARCH_HAS_CACHE_LINE_SIZE 72 select ARCH_HAS_DEBUG_VIRTUAL 73 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 74 select ARCH_HAS_DEVMEM_IS_ALLOWED 75 select ARCH_HAS_EARLY_DEBUG if KGDB 76 select ARCH_HAS_ELF_RANDOMIZE 77 select ARCH_HAS_FAST_MULTIPLIER 78 select ARCH_HAS_FILTER_PGPROT 79 select ARCH_HAS_FORTIFY_SOURCE 80 select ARCH_HAS_GCOV_PROFILE_ALL 81 select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION 82 select ARCH_HAS_MEM_ENCRYPT 83 select ARCH_HAS_MEMBARRIER_SYNC_CORE 84 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 85 select ARCH_HAS_PMEM_API if X86_64 86 select ARCH_HAS_PTE_DEVMAP if X86_64 87 select ARCH_HAS_PTE_SPECIAL 88 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 89 select ARCH_HAS_COPY_MC if X86_64 90 select ARCH_HAS_SET_MEMORY 91 select ARCH_HAS_SET_DIRECT_MAP 92 select ARCH_HAS_STRICT_KERNEL_RWX 93 select ARCH_HAS_STRICT_MODULE_RWX 94 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 95 select ARCH_HAS_SYSCALL_WRAPPER 96 select ARCH_HAS_UBSAN_SANITIZE_ALL 97 select ARCH_HAS_DEBUG_WX 98 select ARCH_HAS_ZONE_DMA_SET if EXPERT 99 select ARCH_HAVE_NMI_SAFE_CMPXCHG 100 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 101 select ARCH_MIGHT_HAVE_PC_PARPORT 102 select ARCH_MIGHT_HAVE_PC_SERIO 103 select ARCH_STACKWALK 104 select ARCH_SUPPORTS_ACPI 105 select ARCH_SUPPORTS_ATOMIC_RMW 106 select ARCH_SUPPORTS_DEBUG_PAGEALLOC 107 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 108 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 109 select ARCH_SUPPORTS_LTO_CLANG 110 select ARCH_SUPPORTS_LTO_CLANG_THIN 111 select ARCH_USE_BUILTIN_BSWAP 112 select ARCH_USE_MEMTEST 113 select ARCH_USE_QUEUED_RWLOCKS 114 select ARCH_USE_QUEUED_SPINLOCKS 115 select ARCH_USE_SYM_ANNOTATIONS 116 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 117 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 118 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 119 select ARCH_WANTS_NO_INSTR 120 select ARCH_WANT_HUGE_PMD_SHARE 121 select ARCH_WANT_LD_ORPHAN_WARN 122 select ARCH_WANTS_THP_SWAP if X86_64 123 select ARCH_HAS_PARANOID_L1D_FLUSH 124 select BUILDTIME_TABLE_SORT 125 select CLKEVT_I8253 126 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 127 select CLOCKSOURCE_WATCHDOG 128 select DCACHE_WORD_ACCESS 129 select DYNAMIC_SIGFRAME 130 select EDAC_ATOMIC_SCRUB 131 select EDAC_SUPPORT 132 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 133 select GENERIC_CLOCKEVENTS_MIN_ADJUST 134 select GENERIC_CMOS_UPDATE 135 select GENERIC_CPU_AUTOPROBE 136 select GENERIC_CPU_VULNERABILITIES 137 select GENERIC_EARLY_IOREMAP 138 select GENERIC_ENTRY 139 select GENERIC_FIND_FIRST_BIT 140 select GENERIC_IOMAP 141 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 142 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 143 select GENERIC_IRQ_MIGRATION if SMP 144 select GENERIC_IRQ_PROBE 145 select GENERIC_IRQ_RESERVATION_MODE 146 select GENERIC_IRQ_SHOW 147 select GENERIC_PENDING_IRQ if SMP 148 select GENERIC_PTDUMP 149 select GENERIC_SMP_IDLE_THREAD 150 select GENERIC_TIME_VSYSCALL 151 select GENERIC_GETTIMEOFDAY 152 select GENERIC_VDSO_TIME_NS 153 select GUP_GET_PTE_LOW_HIGH if X86_PAE 154 select HARDIRQS_SW_RESEND 155 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 156 select HAVE_ACPI_APEI if ACPI 157 select HAVE_ACPI_APEI_NMI if ACPI 158 select HAVE_ALIGNED_STRUCT_PAGE if SLUB 159 select HAVE_ARCH_AUDITSYSCALL 160 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 161 select HAVE_ARCH_JUMP_LABEL 162 select HAVE_ARCH_JUMP_LABEL_RELATIVE 163 select HAVE_ARCH_KASAN if X86_64 164 select HAVE_ARCH_KASAN_VMALLOC if X86_64 165 select HAVE_ARCH_KFENCE 166 select HAVE_ARCH_KGDB 167 select HAVE_ARCH_MMAP_RND_BITS if MMU 168 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 169 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 170 select HAVE_ARCH_PREL32_RELOCATIONS 171 select HAVE_ARCH_SECCOMP_FILTER 172 select HAVE_ARCH_THREAD_STRUCT_WHITELIST 173 select HAVE_ARCH_STACKLEAK 174 select HAVE_ARCH_TRACEHOOK 175 select HAVE_ARCH_TRANSPARENT_HUGEPAGE 176 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 177 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 178 select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 179 select HAVE_ARCH_VMAP_STACK if X86_64 180 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 181 select HAVE_ARCH_WITHIN_STACK_FRAMES 182 select HAVE_ASM_MODVERSIONS 183 select HAVE_CMPXCHG_DOUBLE 184 select HAVE_CMPXCHG_LOCAL 185 select HAVE_CONTEXT_TRACKING if X86_64 186 select HAVE_CONTEXT_TRACKING_OFFSTACK if HAVE_CONTEXT_TRACKING 187 select HAVE_C_RECORDMCOUNT 188 select HAVE_OBJTOOL_MCOUNT if STACK_VALIDATION 189 select HAVE_DEBUG_KMEMLEAK 190 select HAVE_DMA_CONTIGUOUS 191 select HAVE_DYNAMIC_FTRACE 192 select HAVE_DYNAMIC_FTRACE_WITH_REGS 193 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 194 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 195 select HAVE_EBPF_JIT 196 select HAVE_EFFICIENT_UNALIGNED_ACCESS 197 select HAVE_EISA 198 select HAVE_EXIT_THREAD 199 select HAVE_FAST_GUP 200 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 201 select HAVE_FTRACE_MCOUNT_RECORD 202 select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) 203 select HAVE_FUNCTION_TRACER 204 select HAVE_GCC_PLUGINS 205 select HAVE_HW_BREAKPOINT 206 select HAVE_IOREMAP_PROT 207 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 208 select HAVE_IRQ_TIME_ACCOUNTING 209 select HAVE_KERNEL_BZIP2 210 select HAVE_KERNEL_GZIP 211 select HAVE_KERNEL_LZ4 212 select HAVE_KERNEL_LZMA 213 select HAVE_KERNEL_LZO 214 select HAVE_KERNEL_XZ 215 select HAVE_KERNEL_ZSTD 216 select HAVE_KPROBES 217 select HAVE_KPROBES_ON_FTRACE 218 select HAVE_FUNCTION_ERROR_INJECTION 219 select HAVE_KRETPROBES 220 select HAVE_KVM 221 select HAVE_LIVEPATCH if X86_64 222 select HAVE_MIXED_BREAKPOINTS_REGS 223 select HAVE_MOD_ARCH_SPECIFIC 224 select HAVE_MOVE_PMD 225 select HAVE_MOVE_PUD 226 select HAVE_NMI 227 select HAVE_OPTPROBES 228 select HAVE_PCSPKR_PLATFORM 229 select HAVE_PERF_EVENTS 230 select HAVE_PERF_EVENTS_NMI 231 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 232 select HAVE_PCI 233 select HAVE_PERF_REGS 234 select HAVE_PERF_USER_STACK_DUMP 235 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 236 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 237 select HAVE_REGS_AND_STACK_ACCESS_API 238 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 239 select HAVE_FUNCTION_ARG_ACCESS_API 240 select HAVE_SOFTIRQ_ON_OWN_STACK 241 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 242 select HAVE_STACK_VALIDATION if X86_64 243 select HAVE_STATIC_CALL 244 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION 245 select HAVE_PREEMPT_DYNAMIC 246 select HAVE_RSEQ 247 select HAVE_SYSCALL_TRACEPOINTS 248 select HAVE_UNSTABLE_SCHED_CLOCK 249 select HAVE_USER_RETURN_NOTIFIER 250 select HAVE_GENERIC_VDSO 251 select HOTPLUG_SMT if SMP 252 select IRQ_FORCED_THREADING 253 select NEED_SG_DMA_LENGTH 254 select PCI_DOMAINS if PCI 255 select PCI_LOCKLESS_CONFIG if PCI 256 select PERF_EVENTS 257 select RTC_LIB 258 select RTC_MC146818_LIB 259 select SPARSE_IRQ 260 select SRCU 261 select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE) 262 select SYSCTL_EXCEPTION_TRACE 263 select THREAD_INFO_IN_TASK 264 select TRACE_IRQFLAGS_SUPPORT 265 select USER_STACKTRACE_SUPPORT 266 select VIRT_TO_BUS 267 select HAVE_ARCH_KCSAN if X86_64 268 select X86_FEATURE_NAMES if PROC_FS 269 select PROC_PID_ARCH_STATUS if PROC_FS 270 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 271 272config INSTRUCTION_DECODER 273 def_bool y 274 depends on KPROBES || PERF_EVENTS || UPROBES 275 276config OUTPUT_FORMAT 277 string 278 default "elf32-i386" if X86_32 279 default "elf64-x86-64" if X86_64 280 281config LOCKDEP_SUPPORT 282 def_bool y 283 284config STACKTRACE_SUPPORT 285 def_bool y 286 287config MMU 288 def_bool y 289 290config ARCH_MMAP_RND_BITS_MIN 291 default 28 if 64BIT 292 default 8 293 294config ARCH_MMAP_RND_BITS_MAX 295 default 32 if 64BIT 296 default 16 297 298config ARCH_MMAP_RND_COMPAT_BITS_MIN 299 default 8 300 301config ARCH_MMAP_RND_COMPAT_BITS_MAX 302 default 16 303 304config SBUS 305 bool 306 307config GENERIC_ISA_DMA 308 def_bool y 309 depends on ISA_DMA_API 310 311config GENERIC_BUG 312 def_bool y 313 depends on BUG 314 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 315 316config GENERIC_BUG_RELATIVE_POINTERS 317 bool 318 319config ARCH_MAY_HAVE_PC_FDC 320 def_bool y 321 depends on ISA_DMA_API 322 323config GENERIC_CALIBRATE_DELAY 324 def_bool y 325 326config ARCH_HAS_CPU_RELAX 327 def_bool y 328 329config ARCH_HAS_FILTER_PGPROT 330 def_bool y 331 332config HAVE_SETUP_PER_CPU_AREA 333 def_bool y 334 335config NEED_PER_CPU_EMBED_FIRST_CHUNK 336 def_bool y 337 338config NEED_PER_CPU_PAGE_FIRST_CHUNK 339 def_bool y 340 341config ARCH_HIBERNATION_POSSIBLE 342 def_bool y 343 344config ARCH_NR_GPIO 345 int 346 default 1024 if X86_64 347 default 512 348 349config ARCH_SUSPEND_POSSIBLE 350 def_bool y 351 352config ARCH_WANT_GENERAL_HUGETLB 353 def_bool y 354 355config AUDIT_ARCH 356 def_bool y if X86_64 357 358config KASAN_SHADOW_OFFSET 359 hex 360 depends on KASAN 361 default 0xdffffc0000000000 362 363config HAVE_INTEL_TXT 364 def_bool y 365 depends on INTEL_IOMMU && ACPI 366 367config X86_32_SMP 368 def_bool y 369 depends on X86_32 && SMP 370 371config X86_64_SMP 372 def_bool y 373 depends on X86_64 && SMP 374 375config ARCH_SUPPORTS_UPROBES 376 def_bool y 377 378config FIX_EARLYCON_MEM 379 def_bool y 380 381config DYNAMIC_PHYSICAL_MASK 382 bool 383 384config PGTABLE_LEVELS 385 int 386 default 5 if X86_5LEVEL 387 default 4 if X86_64 388 default 3 if X86_PAE 389 default 2 390 391config CC_HAS_SANE_STACKPROTECTOR 392 bool 393 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 394 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 395 help 396 We have to make sure stack protector is unconditionally disabled if 397 the compiler produces broken code or if it does not let us control 398 the segment on 32-bit kernels. 399 400menu "Processor type and features" 401 402config SMP 403 bool "Symmetric multi-processing support" 404 help 405 This enables support for systems with more than one CPU. If you have 406 a system with only one CPU, say N. If you have a system with more 407 than one CPU, say Y. 408 409 If you say N here, the kernel will run on uni- and multiprocessor 410 machines, but will use only one CPU of a multiprocessor machine. If 411 you say Y here, the kernel will run on many, but not all, 412 uniprocessor machines. On a uniprocessor machine, the kernel 413 will run faster if you say N here. 414 415 Note that if you say Y here and choose architecture "586" or 416 "Pentium" under "Processor family", the kernel will not work on 486 417 architectures. Similarly, multiprocessor kernels for the "PPro" 418 architecture may not work on all Pentium based boards. 419 420 People using multiprocessor machines who say Y here should also say 421 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 422 Management" code will be disabled if you say Y here. 423 424 See also <file:Documentation/x86/i386/IO-APIC.rst>, 425 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 426 <http://www.tldp.org/docs.html#howto>. 427 428 If you don't know what to do here, say N. 429 430config X86_FEATURE_NAMES 431 bool "Processor feature human-readable names" if EMBEDDED 432 default y 433 help 434 This option compiles in a table of x86 feature bits and corresponding 435 names. This is required to support /proc/cpuinfo and a few kernel 436 messages. You can disable this to save space, at the expense of 437 making those few kernel messages show numeric feature bits instead. 438 439 If in doubt, say Y. 440 441config X86_X2APIC 442 bool "Support x2apic" 443 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 444 help 445 This enables x2apic support on CPUs that have this feature. 446 447 This allows 32-bit apic IDs (so it can support very large systems), 448 and accesses the local apic via MSRs not via mmio. 449 450 If you don't know what to do here, say N. 451 452config X86_MPPARSE 453 bool "Enable MPS table" if ACPI 454 default y 455 depends on X86_LOCAL_APIC 456 help 457 For old smp systems that do not have proper acpi support. Newer systems 458 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 459 460config GOLDFISH 461 def_bool y 462 depends on X86_GOLDFISH 463 464config RETPOLINE 465 bool "Avoid speculative indirect branches in kernel" 466 default y 467 help 468 Compile kernel with the retpoline compiler options to guard against 469 kernel-to-user data leaks by avoiding speculative indirect 470 branches. Requires a compiler with -mindirect-branch=thunk-extern 471 support for full protection. The kernel may run slower. 472 473config X86_CPU_RESCTRL 474 bool "x86 CPU resource control support" 475 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 476 select KERNFS 477 select PROC_CPU_RESCTRL if PROC_FS 478 help 479 Enable x86 CPU resource control support. 480 481 Provide support for the allocation and monitoring of system resources 482 usage by the CPU. 483 484 Intel calls this Intel Resource Director Technology 485 (Intel(R) RDT). More information about RDT can be found in the 486 Intel x86 Architecture Software Developer Manual. 487 488 AMD calls this AMD Platform Quality of Service (AMD QoS). 489 More information about AMD QoS can be found in the AMD64 Technology 490 Platform Quality of Service Extensions manual. 491 492 Say N if unsure. 493 494if X86_32 495config X86_BIGSMP 496 bool "Support for big SMP systems with more than 8 CPUs" 497 depends on SMP 498 help 499 This option is needed for the systems that have more than 8 CPUs. 500 501config X86_EXTENDED_PLATFORM 502 bool "Support for extended (non-PC) x86 platforms" 503 default y 504 help 505 If you disable this option then the kernel will only support 506 standard PC platforms. (which covers the vast majority of 507 systems out there.) 508 509 If you enable this option then you'll be able to select support 510 for the following (non-PC) 32 bit x86 platforms: 511 Goldfish (Android emulator) 512 AMD Elan 513 RDC R-321x SoC 514 SGI 320/540 (Visual Workstation) 515 STA2X11-based (e.g. Northville) 516 Moorestown MID devices 517 518 If you have one of these systems, or if you want to build a 519 generic distribution kernel, say Y here - otherwise say N. 520endif 521 522if X86_64 523config X86_EXTENDED_PLATFORM 524 bool "Support for extended (non-PC) x86 platforms" 525 default y 526 help 527 If you disable this option then the kernel will only support 528 standard PC platforms. (which covers the vast majority of 529 systems out there.) 530 531 If you enable this option then you'll be able to select support 532 for the following (non-PC) 64 bit x86 platforms: 533 Numascale NumaChip 534 ScaleMP vSMP 535 SGI Ultraviolet 536 537 If you have one of these systems, or if you want to build a 538 generic distribution kernel, say Y here - otherwise say N. 539endif 540# This is an alphabetically sorted list of 64 bit extended platforms 541# Please maintain the alphabetic order if and when there are additions 542config X86_NUMACHIP 543 bool "Numascale NumaChip" 544 depends on X86_64 545 depends on X86_EXTENDED_PLATFORM 546 depends on NUMA 547 depends on SMP 548 depends on X86_X2APIC 549 depends on PCI_MMCONFIG 550 help 551 Adds support for Numascale NumaChip large-SMP systems. Needed to 552 enable more than ~168 cores. 553 If you don't have one of these, you should say N here. 554 555config X86_VSMP 556 bool "ScaleMP vSMP" 557 select HYPERVISOR_GUEST 558 select PARAVIRT 559 depends on X86_64 && PCI 560 depends on X86_EXTENDED_PLATFORM 561 depends on SMP 562 help 563 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 564 supposed to run on these EM64T-based machines. Only choose this option 565 if you have one of these machines. 566 567config X86_UV 568 bool "SGI Ultraviolet" 569 depends on X86_64 570 depends on X86_EXTENDED_PLATFORM 571 depends on NUMA 572 depends on EFI 573 depends on KEXEC_CORE 574 depends on X86_X2APIC 575 depends on PCI 576 help 577 This option is needed in order to support SGI Ultraviolet systems. 578 If you don't have one of these, you should say N here. 579 580# Following is an alphabetically sorted list of 32 bit extended platforms 581# Please maintain the alphabetic order if and when there are additions 582 583config X86_GOLDFISH 584 bool "Goldfish (Virtual Platform)" 585 depends on X86_EXTENDED_PLATFORM 586 help 587 Enable support for the Goldfish virtual platform used primarily 588 for Android development. Unless you are building for the Android 589 Goldfish emulator say N here. 590 591config X86_INTEL_CE 592 bool "CE4100 TV platform" 593 depends on PCI 594 depends on PCI_GODIRECT 595 depends on X86_IO_APIC 596 depends on X86_32 597 depends on X86_EXTENDED_PLATFORM 598 select X86_REBOOTFIXUPS 599 select OF 600 select OF_EARLY_FLATTREE 601 help 602 Select for the Intel CE media processor (CE4100) SOC. 603 This option compiles in support for the CE4100 SOC for settop 604 boxes and media devices. 605 606config X86_INTEL_MID 607 bool "Intel MID platform support" 608 depends on X86_EXTENDED_PLATFORM 609 depends on X86_PLATFORM_DEVICES 610 depends on PCI 611 depends on X86_64 || (PCI_GOANY && X86_32) 612 depends on X86_IO_APIC 613 select I2C 614 select DW_APB_TIMER 615 select INTEL_SCU_PCI 616 help 617 Select to build a kernel capable of supporting Intel MID (Mobile 618 Internet Device) platform systems which do not have the PCI legacy 619 interfaces. If you are building for a PC class system say N here. 620 621 Intel MID platforms are based on an Intel processor and chipset which 622 consume less power than most of the x86 derivatives. 623 624config X86_INTEL_QUARK 625 bool "Intel Quark platform support" 626 depends on X86_32 627 depends on X86_EXTENDED_PLATFORM 628 depends on X86_PLATFORM_DEVICES 629 depends on X86_TSC 630 depends on PCI 631 depends on PCI_GOANY 632 depends on X86_IO_APIC 633 select IOSF_MBI 634 select INTEL_IMR 635 select COMMON_CLK 636 help 637 Select to include support for Quark X1000 SoC. 638 Say Y here if you have a Quark based system such as the Arduino 639 compatible Intel Galileo. 640 641config X86_INTEL_LPSS 642 bool "Intel Low Power Subsystem Support" 643 depends on X86 && ACPI && PCI 644 select COMMON_CLK 645 select PINCTRL 646 select IOSF_MBI 647 help 648 Select to build support for Intel Low Power Subsystem such as 649 found on Intel Lynxpoint PCH. Selecting this option enables 650 things like clock tree (common clock framework) and pincontrol 651 which are needed by the LPSS peripheral drivers. 652 653config X86_AMD_PLATFORM_DEVICE 654 bool "AMD ACPI2Platform devices support" 655 depends on ACPI 656 select COMMON_CLK 657 select PINCTRL 658 help 659 Select to interpret AMD specific ACPI device to platform device 660 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 661 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 662 implemented under PINCTRL subsystem. 663 664config IOSF_MBI 665 tristate "Intel SoC IOSF Sideband support for SoC platforms" 666 depends on PCI 667 help 668 This option enables sideband register access support for Intel SoC 669 platforms. On these platforms the IOSF sideband is used in lieu of 670 MSR's for some register accesses, mostly but not limited to thermal 671 and power. Drivers may query the availability of this device to 672 determine if they need the sideband in order to work on these 673 platforms. The sideband is available on the following SoC products. 674 This list is not meant to be exclusive. 675 - BayTrail 676 - Braswell 677 - Quark 678 679 You should say Y if you are running a kernel on one of these SoC's. 680 681config IOSF_MBI_DEBUG 682 bool "Enable IOSF sideband access through debugfs" 683 depends on IOSF_MBI && DEBUG_FS 684 help 685 Select this option to expose the IOSF sideband access registers (MCR, 686 MDR, MCRX) through debugfs to write and read register information from 687 different units on the SoC. This is most useful for obtaining device 688 state information for debug and analysis. As this is a general access 689 mechanism, users of this option would have specific knowledge of the 690 device they want to access. 691 692 If you don't require the option or are in doubt, say N. 693 694config X86_RDC321X 695 bool "RDC R-321x SoC" 696 depends on X86_32 697 depends on X86_EXTENDED_PLATFORM 698 select M486 699 select X86_REBOOTFIXUPS 700 help 701 This option is needed for RDC R-321x system-on-chip, also known 702 as R-8610-(G). 703 If you don't have one of these chips, you should say N here. 704 705config X86_32_NON_STANDARD 706 bool "Support non-standard 32-bit SMP architectures" 707 depends on X86_32 && SMP 708 depends on X86_EXTENDED_PLATFORM 709 help 710 This option compiles in the bigsmp and STA2X11 default 711 subarchitectures. It is intended for a generic binary 712 kernel. If you select them all, kernel will probe it one by 713 one and will fallback to default. 714 715# Alphabetically sorted list of Non standard 32 bit platforms 716 717config X86_SUPPORTS_MEMORY_FAILURE 718 def_bool y 719 # MCE code calls memory_failure(): 720 depends on X86_MCE 721 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 722 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 723 depends on X86_64 || !SPARSEMEM 724 select ARCH_SUPPORTS_MEMORY_FAILURE 725 726config STA2X11 727 bool "STA2X11 Companion Chip Support" 728 depends on X86_32_NON_STANDARD && PCI 729 select SWIOTLB 730 select MFD_STA2X11 731 select GPIOLIB 732 help 733 This adds support for boards based on the STA2X11 IO-Hub, 734 a.k.a. "ConneXt". The chip is used in place of the standard 735 PC chipset, so all "standard" peripherals are missing. If this 736 option is selected the kernel will still be able to boot on 737 standard PC machines. 738 739config X86_32_IRIS 740 tristate "Eurobraille/Iris poweroff module" 741 depends on X86_32 742 help 743 The Iris machines from EuroBraille do not have APM or ACPI support 744 to shut themselves down properly. A special I/O sequence is 745 needed to do so, which is what this module does at 746 kernel shutdown. 747 748 This is only for Iris machines from EuroBraille. 749 750 If unused, say N. 751 752config SCHED_OMIT_FRAME_POINTER 753 def_bool y 754 prompt "Single-depth WCHAN output" 755 depends on X86 756 help 757 Calculate simpler /proc/<PID>/wchan values. If this option 758 is disabled then wchan values will recurse back to the 759 caller function. This provides more accurate wchan values, 760 at the expense of slightly more scheduling overhead. 761 762 If in doubt, say "Y". 763 764menuconfig HYPERVISOR_GUEST 765 bool "Linux guest support" 766 help 767 Say Y here to enable options for running Linux under various hyper- 768 visors. This option enables basic hypervisor detection and platform 769 setup. 770 771 If you say N, all options in this submenu will be skipped and 772 disabled, and Linux guest support won't be built in. 773 774if HYPERVISOR_GUEST 775 776config PARAVIRT 777 bool "Enable paravirtualization code" 778 depends on HAVE_STATIC_CALL 779 help 780 This changes the kernel so it can modify itself when it is run 781 under a hypervisor, potentially improving performance significantly 782 over full virtualization. However, when run without a hypervisor 783 the kernel is theoretically slower and slightly larger. 784 785config PARAVIRT_XXL 786 bool 787 788config PARAVIRT_DEBUG 789 bool "paravirt-ops debugging" 790 depends on PARAVIRT && DEBUG_KERNEL 791 help 792 Enable to debug paravirt_ops internals. Specifically, BUG if 793 a paravirt_op is missing when it is called. 794 795config PARAVIRT_SPINLOCKS 796 bool "Paravirtualization layer for spinlocks" 797 depends on PARAVIRT && SMP 798 help 799 Paravirtualized spinlocks allow a pvops backend to replace the 800 spinlock implementation with something virtualization-friendly 801 (for example, block the virtual CPU rather than spinning). 802 803 It has a minimal impact on native kernels and gives a nice performance 804 benefit on paravirtualized KVM / Xen kernels. 805 806 If you are unsure how to answer this question, answer Y. 807 808config X86_HV_CALLBACK_VECTOR 809 def_bool n 810 811source "arch/x86/xen/Kconfig" 812 813config KVM_GUEST 814 bool "KVM Guest support (including kvmclock)" 815 depends on PARAVIRT 816 select PARAVIRT_CLOCK 817 select ARCH_CPUIDLE_HALTPOLL 818 select X86_HV_CALLBACK_VECTOR 819 default y 820 help 821 This option enables various optimizations for running under the KVM 822 hypervisor. It includes a paravirtualized clock, so that instead 823 of relying on a PIT (or probably other) emulation by the 824 underlying device model, the host provides the guest with 825 timing infrastructure such as time of day, and system time 826 827config ARCH_CPUIDLE_HALTPOLL 828 def_bool n 829 prompt "Disable host haltpoll when loading haltpoll driver" 830 help 831 If virtualized under KVM, disable host haltpoll. 832 833config PVH 834 bool "Support for running PVH guests" 835 help 836 This option enables the PVH entry point for guest virtual machines 837 as specified in the x86/HVM direct boot ABI. 838 839config PARAVIRT_TIME_ACCOUNTING 840 bool "Paravirtual steal time accounting" 841 depends on PARAVIRT 842 help 843 Select this option to enable fine granularity task steal time 844 accounting. Time spent executing other tasks in parallel with 845 the current vCPU is discounted from the vCPU power. To account for 846 that, there can be a small performance impact. 847 848 If in doubt, say N here. 849 850config PARAVIRT_CLOCK 851 bool 852 853config JAILHOUSE_GUEST 854 bool "Jailhouse non-root cell support" 855 depends on X86_64 && PCI 856 select X86_PM_TIMER 857 help 858 This option allows to run Linux as guest in a Jailhouse non-root 859 cell. You can leave this option disabled if you only want to start 860 Jailhouse and run Linux afterwards in the root cell. 861 862config ACRN_GUEST 863 bool "ACRN Guest support" 864 depends on X86_64 865 select X86_HV_CALLBACK_VECTOR 866 help 867 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 868 a flexible, lightweight reference open-source hypervisor, built with 869 real-time and safety-criticality in mind. It is built for embedded 870 IOT with small footprint and real-time features. More details can be 871 found in https://projectacrn.org/. 872 873endif #HYPERVISOR_GUEST 874 875source "arch/x86/Kconfig.cpu" 876 877config HPET_TIMER 878 def_bool X86_64 879 prompt "HPET Timer Support" if X86_32 880 help 881 Use the IA-PC HPET (High Precision Event Timer) to manage 882 time in preference to the PIT and RTC, if a HPET is 883 present. 884 HPET is the next generation timer replacing legacy 8254s. 885 The HPET provides a stable time base on SMP 886 systems, unlike the TSC, but it is more expensive to access, 887 as it is off-chip. The interface used is documented 888 in the HPET spec, revision 1. 889 890 You can safely choose Y here. However, HPET will only be 891 activated if the platform and the BIOS support this feature. 892 Otherwise the 8254 will be used for timing services. 893 894 Choose N to continue using the legacy 8254 timer. 895 896config HPET_EMULATE_RTC 897 def_bool y 898 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 899 900# Mark as expert because too many people got it wrong. 901# The code disables itself when not needed. 902config DMI 903 default y 904 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 905 bool "Enable DMI scanning" if EXPERT 906 help 907 Enabled scanning of DMI to identify machine quirks. Say Y 908 here unless you have verified that your setup is not 909 affected by entries in the DMI blacklist. Required by PNP 910 BIOS code. 911 912config GART_IOMMU 913 bool "Old AMD GART IOMMU support" 914 select DMA_OPS 915 select IOMMU_HELPER 916 select SWIOTLB 917 depends on X86_64 && PCI && AMD_NB 918 help 919 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 920 GART based hardware IOMMUs. 921 922 The GART supports full DMA access for devices with 32-bit access 923 limitations, on systems with more than 3 GB. This is usually needed 924 for USB, sound, many IDE/SATA chipsets and some other devices. 925 926 Newer systems typically have a modern AMD IOMMU, supported via 927 the CONFIG_AMD_IOMMU=y config option. 928 929 In normal configurations this driver is only active when needed: 930 there's more than 3 GB of memory and the system contains a 931 32-bit limited device. 932 933 If unsure, say Y. 934 935config MAXSMP 936 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 937 depends on X86_64 && SMP && DEBUG_KERNEL 938 select CPUMASK_OFFSTACK 939 help 940 Enable maximum number of CPUS and NUMA Nodes for this architecture. 941 If unsure, say N. 942 943# 944# The maximum number of CPUs supported: 945# 946# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 947# and which can be configured interactively in the 948# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 949# 950# The ranges are different on 32-bit and 64-bit kernels, depending on 951# hardware capabilities and scalability features of the kernel. 952# 953# ( If MAXSMP is enabled we just use the highest possible value and disable 954# interactive configuration. ) 955# 956 957config NR_CPUS_RANGE_BEGIN 958 int 959 default NR_CPUS_RANGE_END if MAXSMP 960 default 1 if !SMP 961 default 2 962 963config NR_CPUS_RANGE_END 964 int 965 depends on X86_32 966 default 64 if SMP && X86_BIGSMP 967 default 8 if SMP && !X86_BIGSMP 968 default 1 if !SMP 969 970config NR_CPUS_RANGE_END 971 int 972 depends on X86_64 973 default 8192 if SMP && CPUMASK_OFFSTACK 974 default 512 if SMP && !CPUMASK_OFFSTACK 975 default 1 if !SMP 976 977config NR_CPUS_DEFAULT 978 int 979 depends on X86_32 980 default 32 if X86_BIGSMP 981 default 8 if SMP 982 default 1 if !SMP 983 984config NR_CPUS_DEFAULT 985 int 986 depends on X86_64 987 default 8192 if MAXSMP 988 default 64 if SMP 989 default 1 if !SMP 990 991config NR_CPUS 992 int "Maximum number of CPUs" if SMP && !MAXSMP 993 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 994 default NR_CPUS_DEFAULT 995 help 996 This allows you to specify the maximum number of CPUs which this 997 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 998 supported value is 8192, otherwise the maximum value is 512. The 999 minimum value which makes sense is 2. 1000 1001 This is purely to save memory: each supported CPU adds about 8KB 1002 to the kernel image. 1003 1004config SCHED_CLUSTER 1005 bool "Cluster scheduler support" 1006 depends on SMP 1007 default y 1008 help 1009 Cluster scheduler support improves the CPU scheduler's decision 1010 making when dealing with machines that have clusters of CPUs. 1011 Cluster usually means a couple of CPUs which are placed closely 1012 by sharing mid-level caches, last-level cache tags or internal 1013 busses. 1014 1015config SCHED_SMT 1016 def_bool y if SMP 1017 1018config SCHED_MC 1019 def_bool y 1020 prompt "Multi-core scheduler support" 1021 depends on SMP 1022 help 1023 Multi-core scheduler support improves the CPU scheduler's decision 1024 making when dealing with multi-core CPU chips at a cost of slightly 1025 increased overhead in some places. If unsure say N here. 1026 1027config SCHED_MC_PRIO 1028 bool "CPU core priorities scheduler support" 1029 depends on SCHED_MC && CPU_SUP_INTEL 1030 select X86_INTEL_PSTATE 1031 select CPU_FREQ 1032 default y 1033 help 1034 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1035 core ordering determined at manufacturing time, which allows 1036 certain cores to reach higher turbo frequencies (when running 1037 single threaded workloads) than others. 1038 1039 Enabling this kernel feature teaches the scheduler about 1040 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1041 scheduler's CPU selection logic accordingly, so that higher 1042 overall system performance can be achieved. 1043 1044 This feature will have no effect on CPUs without this feature. 1045 1046 If unsure say Y here. 1047 1048config UP_LATE_INIT 1049 def_bool y 1050 depends on !SMP && X86_LOCAL_APIC 1051 1052config X86_UP_APIC 1053 bool "Local APIC support on uniprocessors" if !PCI_MSI 1054 default PCI_MSI 1055 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1056 help 1057 A local APIC (Advanced Programmable Interrupt Controller) is an 1058 integrated interrupt controller in the CPU. If you have a single-CPU 1059 system which has a processor with a local APIC, you can say Y here to 1060 enable and use it. If you say Y here even though your machine doesn't 1061 have a local APIC, then the kernel will still run with no slowdown at 1062 all. The local APIC supports CPU-generated self-interrupts (timer, 1063 performance counters), and the NMI watchdog which detects hard 1064 lockups. 1065 1066config X86_UP_IOAPIC 1067 bool "IO-APIC support on uniprocessors" 1068 depends on X86_UP_APIC 1069 help 1070 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1071 SMP-capable replacement for PC-style interrupt controllers. Most 1072 SMP systems and many recent uniprocessor systems have one. 1073 1074 If you have a single-CPU system with an IO-APIC, you can say Y here 1075 to use it. If you say Y here even though your machine doesn't have 1076 an IO-APIC, then the kernel will still run with no slowdown at all. 1077 1078config X86_LOCAL_APIC 1079 def_bool y 1080 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1081 select IRQ_DOMAIN_HIERARCHY 1082 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1083 1084config X86_IO_APIC 1085 def_bool y 1086 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1087 1088config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1089 bool "Reroute for broken boot IRQs" 1090 depends on X86_IO_APIC 1091 help 1092 This option enables a workaround that fixes a source of 1093 spurious interrupts. This is recommended when threaded 1094 interrupt handling is used on systems where the generation of 1095 superfluous "boot interrupts" cannot be disabled. 1096 1097 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1098 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1099 kernel does during interrupt handling). On chipsets where this 1100 boot IRQ generation cannot be disabled, this workaround keeps 1101 the original IRQ line masked so that only the equivalent "boot 1102 IRQ" is delivered to the CPUs. The workaround also tells the 1103 kernel to set up the IRQ handler on the boot IRQ line. In this 1104 way only one interrupt is delivered to the kernel. Otherwise 1105 the spurious second interrupt may cause the kernel to bring 1106 down (vital) interrupt lines. 1107 1108 Only affects "broken" chipsets. Interrupt sharing may be 1109 increased on these systems. 1110 1111config X86_MCE 1112 bool "Machine Check / overheating reporting" 1113 select GENERIC_ALLOCATOR 1114 default y 1115 help 1116 Machine Check support allows the processor to notify the 1117 kernel if it detects a problem (e.g. overheating, data corruption). 1118 The action the kernel takes depends on the severity of the problem, 1119 ranging from warning messages to halting the machine. 1120 1121config X86_MCELOG_LEGACY 1122 bool "Support for deprecated /dev/mcelog character device" 1123 depends on X86_MCE 1124 help 1125 Enable support for /dev/mcelog which is needed by the old mcelog 1126 userspace logging daemon. Consider switching to the new generation 1127 rasdaemon solution. 1128 1129config X86_MCE_INTEL 1130 def_bool y 1131 prompt "Intel MCE features" 1132 depends on X86_MCE && X86_LOCAL_APIC 1133 help 1134 Additional support for intel specific MCE features such as 1135 the thermal monitor. 1136 1137config X86_MCE_AMD 1138 def_bool y 1139 prompt "AMD MCE features" 1140 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1141 help 1142 Additional support for AMD specific MCE features such as 1143 the DRAM Error Threshold. 1144 1145config X86_ANCIENT_MCE 1146 bool "Support for old Pentium 5 / WinChip machine checks" 1147 depends on X86_32 && X86_MCE 1148 help 1149 Include support for machine check handling on old Pentium 5 or WinChip 1150 systems. These typically need to be enabled explicitly on the command 1151 line. 1152 1153config X86_MCE_THRESHOLD 1154 depends on X86_MCE_AMD || X86_MCE_INTEL 1155 def_bool y 1156 1157config X86_MCE_INJECT 1158 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1159 tristate "Machine check injector support" 1160 help 1161 Provide support for injecting machine checks for testing purposes. 1162 If you don't know what a machine check is and you don't do kernel 1163 QA it is safe to say n. 1164 1165source "arch/x86/events/Kconfig" 1166 1167config X86_LEGACY_VM86 1168 bool "Legacy VM86 support" 1169 depends on X86_32 1170 help 1171 This option allows user programs to put the CPU into V8086 1172 mode, which is an 80286-era approximation of 16-bit real mode. 1173 1174 Some very old versions of X and/or vbetool require this option 1175 for user mode setting. Similarly, DOSEMU will use it if 1176 available to accelerate real mode DOS programs. However, any 1177 recent version of DOSEMU, X, or vbetool should be fully 1178 functional even without kernel VM86 support, as they will all 1179 fall back to software emulation. Nevertheless, if you are using 1180 a 16-bit DOS program where 16-bit performance matters, vm86 1181 mode might be faster than emulation and you might want to 1182 enable this option. 1183 1184 Note that any app that works on a 64-bit kernel is unlikely to 1185 need this option, as 64-bit kernels don't, and can't, support 1186 V8086 mode. This option is also unrelated to 16-bit protected 1187 mode and is not needed to run most 16-bit programs under Wine. 1188 1189 Enabling this option increases the complexity of the kernel 1190 and slows down exception handling a tiny bit. 1191 1192 If unsure, say N here. 1193 1194config VM86 1195 bool 1196 default X86_LEGACY_VM86 1197 1198config X86_16BIT 1199 bool "Enable support for 16-bit segments" if EXPERT 1200 default y 1201 depends on MODIFY_LDT_SYSCALL 1202 help 1203 This option is required by programs like Wine to run 16-bit 1204 protected mode legacy code on x86 processors. Disabling 1205 this option saves about 300 bytes on i386, or around 6K text 1206 plus 16K runtime memory on x86-64, 1207 1208config X86_ESPFIX32 1209 def_bool y 1210 depends on X86_16BIT && X86_32 1211 1212config X86_ESPFIX64 1213 def_bool y 1214 depends on X86_16BIT && X86_64 1215 1216config X86_VSYSCALL_EMULATION 1217 bool "Enable vsyscall emulation" if EXPERT 1218 default y 1219 depends on X86_64 1220 help 1221 This enables emulation of the legacy vsyscall page. Disabling 1222 it is roughly equivalent to booting with vsyscall=none, except 1223 that it will also disable the helpful warning if a program 1224 tries to use a vsyscall. With this option set to N, offending 1225 programs will just segfault, citing addresses of the form 1226 0xffffffffff600?00. 1227 1228 This option is required by many programs built before 2013, and 1229 care should be used even with newer programs if set to N. 1230 1231 Disabling this option saves about 7K of kernel size and 1232 possibly 4K of additional runtime pagetable memory. 1233 1234config X86_IOPL_IOPERM 1235 bool "IOPERM and IOPL Emulation" 1236 default y 1237 help 1238 This enables the ioperm() and iopl() syscalls which are necessary 1239 for legacy applications. 1240 1241 Legacy IOPL support is an overbroad mechanism which allows user 1242 space aside of accessing all 65536 I/O ports also to disable 1243 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1244 capabilities and permission from potentially active security 1245 modules. 1246 1247 The emulation restricts the functionality of the syscall to 1248 only allowing the full range I/O port access, but prevents the 1249 ability to disable interrupts from user space which would be 1250 granted if the hardware IOPL mechanism would be used. 1251 1252config TOSHIBA 1253 tristate "Toshiba Laptop support" 1254 depends on X86_32 1255 help 1256 This adds a driver to safely access the System Management Mode of 1257 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1258 not work on models with a Phoenix BIOS. The System Management Mode 1259 is used to set the BIOS and power saving options on Toshiba portables. 1260 1261 For information on utilities to make use of this driver see the 1262 Toshiba Linux utilities web site at: 1263 <http://www.buzzard.org.uk/toshiba/>. 1264 1265 Say Y if you intend to run this kernel on a Toshiba portable. 1266 Say N otherwise. 1267 1268config I8K 1269 tristate "Dell i8k legacy laptop support" 1270 depends on HWMON 1271 depends on PROC_FS 1272 select SENSORS_DELL_SMM 1273 help 1274 This option enables legacy /proc/i8k userspace interface in hwmon 1275 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1276 temperature and allows controlling fan speeds of Dell laptops via 1277 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1278 it reports also power and hotkey status. For fan speed control is 1279 needed userspace package i8kutils. 1280 1281 Say Y if you intend to run this kernel on old Dell laptops or want to 1282 use userspace package i8kutils. 1283 Say N otherwise. 1284 1285config X86_REBOOTFIXUPS 1286 bool "Enable X86 board specific fixups for reboot" 1287 depends on X86_32 1288 help 1289 This enables chipset and/or board specific fixups to be done 1290 in order to get reboot to work correctly. This is only needed on 1291 some combinations of hardware and BIOS. The symptom, for which 1292 this config is intended, is when reboot ends with a stalled/hung 1293 system. 1294 1295 Currently, the only fixup is for the Geode machines using 1296 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1297 1298 Say Y if you want to enable the fixup. Currently, it's safe to 1299 enable this option even if you don't need it. 1300 Say N otherwise. 1301 1302config MICROCODE 1303 bool "CPU microcode loading support" 1304 default y 1305 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1306 help 1307 If you say Y here, you will be able to update the microcode on 1308 Intel and AMD processors. The Intel support is for the IA32 family, 1309 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1310 AMD support is for families 0x10 and later. You will obviously need 1311 the actual microcode binary data itself which is not shipped with 1312 the Linux kernel. 1313 1314 The preferred method to load microcode from a detached initrd is described 1315 in Documentation/x86/microcode.rst. For that you need to enable 1316 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1317 initrd for microcode blobs. 1318 1319 In addition, you can build the microcode into the kernel. For that you 1320 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1321 config option. 1322 1323config MICROCODE_INTEL 1324 bool "Intel microcode loading support" 1325 depends on MICROCODE 1326 default MICROCODE 1327 help 1328 This options enables microcode patch loading support for Intel 1329 processors. 1330 1331 For the current Intel microcode data package go to 1332 <https://downloadcenter.intel.com> and search for 1333 'Linux Processor Microcode Data File'. 1334 1335config MICROCODE_AMD 1336 bool "AMD microcode loading support" 1337 depends on MICROCODE 1338 help 1339 If you select this option, microcode patch loading support for AMD 1340 processors will be enabled. 1341 1342config MICROCODE_OLD_INTERFACE 1343 bool "Ancient loading interface (DEPRECATED)" 1344 default n 1345 depends on MICROCODE 1346 help 1347 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1348 which was used by userspace tools like iucode_tool and microcode.ctl. 1349 It is inadequate because it runs too late to be able to properly 1350 load microcode on a machine and it needs special tools. Instead, you 1351 should've switched to the early loading method with the initrd or 1352 builtin microcode by now: Documentation/x86/microcode.rst 1353 1354config X86_MSR 1355 tristate "/dev/cpu/*/msr - Model-specific register support" 1356 help 1357 This device gives privileged processes access to the x86 1358 Model-Specific Registers (MSRs). It is a character device with 1359 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1360 MSR accesses are directed to a specific CPU on multi-processor 1361 systems. 1362 1363config X86_CPUID 1364 tristate "/dev/cpu/*/cpuid - CPU information support" 1365 help 1366 This device gives processes access to the x86 CPUID instruction to 1367 be executed on a specific processor. It is a character device 1368 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1369 /dev/cpu/31/cpuid. 1370 1371choice 1372 prompt "High Memory Support" 1373 default HIGHMEM4G 1374 depends on X86_32 1375 1376config NOHIGHMEM 1377 bool "off" 1378 help 1379 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1380 However, the address space of 32-bit x86 processors is only 4 1381 Gigabytes large. That means that, if you have a large amount of 1382 physical memory, not all of it can be "permanently mapped" by the 1383 kernel. The physical memory that's not permanently mapped is called 1384 "high memory". 1385 1386 If you are compiling a kernel which will never run on a machine with 1387 more than 1 Gigabyte total physical RAM, answer "off" here (default 1388 choice and suitable for most users). This will result in a "3GB/1GB" 1389 split: 3GB are mapped so that each process sees a 3GB virtual memory 1390 space and the remaining part of the 4GB virtual memory space is used 1391 by the kernel to permanently map as much physical memory as 1392 possible. 1393 1394 If the machine has between 1 and 4 Gigabytes physical RAM, then 1395 answer "4GB" here. 1396 1397 If more than 4 Gigabytes is used then answer "64GB" here. This 1398 selection turns Intel PAE (Physical Address Extension) mode on. 1399 PAE implements 3-level paging on IA32 processors. PAE is fully 1400 supported by Linux, PAE mode is implemented on all recent Intel 1401 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1402 then the kernel will not boot on CPUs that don't support PAE! 1403 1404 The actual amount of total physical memory will either be 1405 auto detected or can be forced by using a kernel command line option 1406 such as "mem=256M". (Try "man bootparam" or see the documentation of 1407 your boot loader (lilo or loadlin) about how to pass options to the 1408 kernel at boot time.) 1409 1410 If unsure, say "off". 1411 1412config HIGHMEM4G 1413 bool "4GB" 1414 help 1415 Select this if you have a 32-bit processor and between 1 and 4 1416 gigabytes of physical RAM. 1417 1418config HIGHMEM64G 1419 bool "64GB" 1420 depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6 1421 select X86_PAE 1422 help 1423 Select this if you have a 32-bit processor and more than 4 1424 gigabytes of physical RAM. 1425 1426endchoice 1427 1428choice 1429 prompt "Memory split" if EXPERT 1430 default VMSPLIT_3G 1431 depends on X86_32 1432 help 1433 Select the desired split between kernel and user memory. 1434 1435 If the address range available to the kernel is less than the 1436 physical memory installed, the remaining memory will be available 1437 as "high memory". Accessing high memory is a little more costly 1438 than low memory, as it needs to be mapped into the kernel first. 1439 Note that increasing the kernel address space limits the range 1440 available to user programs, making the address space there 1441 tighter. Selecting anything other than the default 3G/1G split 1442 will also likely make your kernel incompatible with binary-only 1443 kernel modules. 1444 1445 If you are not absolutely sure what you are doing, leave this 1446 option alone! 1447 1448 config VMSPLIT_3G 1449 bool "3G/1G user/kernel split" 1450 config VMSPLIT_3G_OPT 1451 depends on !X86_PAE 1452 bool "3G/1G user/kernel split (for full 1G low memory)" 1453 config VMSPLIT_2G 1454 bool "2G/2G user/kernel split" 1455 config VMSPLIT_2G_OPT 1456 depends on !X86_PAE 1457 bool "2G/2G user/kernel split (for full 2G low memory)" 1458 config VMSPLIT_1G 1459 bool "1G/3G user/kernel split" 1460endchoice 1461 1462config PAGE_OFFSET 1463 hex 1464 default 0xB0000000 if VMSPLIT_3G_OPT 1465 default 0x80000000 if VMSPLIT_2G 1466 default 0x78000000 if VMSPLIT_2G_OPT 1467 default 0x40000000 if VMSPLIT_1G 1468 default 0xC0000000 1469 depends on X86_32 1470 1471config HIGHMEM 1472 def_bool y 1473 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1474 1475config X86_PAE 1476 bool "PAE (Physical Address Extension) Support" 1477 depends on X86_32 && !HIGHMEM4G 1478 select PHYS_ADDR_T_64BIT 1479 select SWIOTLB 1480 help 1481 PAE is required for NX support, and furthermore enables 1482 larger swapspace support for non-overcommit purposes. It 1483 has the cost of more pagetable lookup overhead, and also 1484 consumes more pagetable space per process. 1485 1486config X86_5LEVEL 1487 bool "Enable 5-level page tables support" 1488 default y 1489 select DYNAMIC_MEMORY_LAYOUT 1490 select SPARSEMEM_VMEMMAP 1491 depends on X86_64 1492 help 1493 5-level paging enables access to larger address space: 1494 upto 128 PiB of virtual address space and 4 PiB of 1495 physical address space. 1496 1497 It will be supported by future Intel CPUs. 1498 1499 A kernel with the option enabled can be booted on machines that 1500 support 4- or 5-level paging. 1501 1502 See Documentation/x86/x86_64/5level-paging.rst for more 1503 information. 1504 1505 Say N if unsure. 1506 1507config X86_DIRECT_GBPAGES 1508 def_bool y 1509 depends on X86_64 1510 help 1511 Certain kernel features effectively disable kernel 1512 linear 1 GB mappings (even if the CPU otherwise 1513 supports them), so don't confuse the user by printing 1514 that we have them enabled. 1515 1516config X86_CPA_STATISTICS 1517 bool "Enable statistic for Change Page Attribute" 1518 depends on DEBUG_FS 1519 help 1520 Expose statistics about the Change Page Attribute mechanism, which 1521 helps to determine the effectiveness of preserving large and huge 1522 page mappings when mapping protections are changed. 1523 1524config AMD_MEM_ENCRYPT 1525 bool "AMD Secure Memory Encryption (SME) support" 1526 depends on X86_64 && CPU_SUP_AMD 1527 select DMA_COHERENT_POOL 1528 select DYNAMIC_PHYSICAL_MASK 1529 select ARCH_USE_MEMREMAP_PROT 1530 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1531 select INSTRUCTION_DECODER 1532 select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS 1533 select ARCH_HAS_CC_PLATFORM 1534 help 1535 Say yes to enable support for the encryption of system memory. 1536 This requires an AMD processor that supports Secure Memory 1537 Encryption (SME). 1538 1539config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1540 bool "Activate AMD Secure Memory Encryption (SME) by default" 1541 depends on AMD_MEM_ENCRYPT 1542 help 1543 Say yes to have system memory encrypted by default if running on 1544 an AMD processor that supports Secure Memory Encryption (SME). 1545 1546 If set to Y, then the encryption of system memory can be 1547 deactivated with the mem_encrypt=off command line option. 1548 1549 If set to N, then the encryption of system memory can be 1550 activated with the mem_encrypt=on command line option. 1551 1552# Common NUMA Features 1553config NUMA 1554 bool "NUMA Memory Allocation and Scheduler Support" 1555 depends on SMP 1556 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1557 default y if X86_BIGSMP 1558 help 1559 Enable NUMA (Non-Uniform Memory Access) support. 1560 1561 The kernel will try to allocate memory used by a CPU on the 1562 local memory controller of the CPU and add some more 1563 NUMA awareness to the kernel. 1564 1565 For 64-bit this is recommended if the system is Intel Core i7 1566 (or later), AMD Opteron, or EM64T NUMA. 1567 1568 For 32-bit this is only needed if you boot a 32-bit 1569 kernel on a 64-bit NUMA platform. 1570 1571 Otherwise, you should say N. 1572 1573config AMD_NUMA 1574 def_bool y 1575 prompt "Old style AMD Opteron NUMA detection" 1576 depends on X86_64 && NUMA && PCI 1577 help 1578 Enable AMD NUMA node topology detection. You should say Y here if 1579 you have a multi processor AMD system. This uses an old method to 1580 read the NUMA configuration directly from the builtin Northbridge 1581 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1582 which also takes priority if both are compiled in. 1583 1584config X86_64_ACPI_NUMA 1585 def_bool y 1586 prompt "ACPI NUMA detection" 1587 depends on X86_64 && NUMA && ACPI && PCI 1588 select ACPI_NUMA 1589 help 1590 Enable ACPI SRAT based node topology detection. 1591 1592config NUMA_EMU 1593 bool "NUMA emulation" 1594 depends on NUMA 1595 help 1596 Enable NUMA emulation. A flat machine will be split 1597 into virtual nodes when booted with "numa=fake=N", where N is the 1598 number of nodes. This is only useful for debugging. 1599 1600config NODES_SHIFT 1601 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1602 range 1 10 1603 default "10" if MAXSMP 1604 default "6" if X86_64 1605 default "3" 1606 depends on NUMA 1607 help 1608 Specify the maximum number of NUMA Nodes available on the target 1609 system. Increases memory reserved to accommodate various tables. 1610 1611config ARCH_FLATMEM_ENABLE 1612 def_bool y 1613 depends on X86_32 && !NUMA 1614 1615config ARCH_SPARSEMEM_ENABLE 1616 def_bool y 1617 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1618 select SPARSEMEM_STATIC if X86_32 1619 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1620 1621config ARCH_SPARSEMEM_DEFAULT 1622 def_bool X86_64 || (NUMA && X86_32) 1623 1624config ARCH_SELECT_MEMORY_MODEL 1625 def_bool y 1626 depends on ARCH_SPARSEMEM_ENABLE 1627 1628config ARCH_MEMORY_PROBE 1629 bool "Enable sysfs memory/probe interface" 1630 depends on X86_64 && MEMORY_HOTPLUG 1631 help 1632 This option enables a sysfs memory/probe interface for testing. 1633 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1634 If you are unsure how to answer this question, answer N. 1635 1636config ARCH_PROC_KCORE_TEXT 1637 def_bool y 1638 depends on X86_64 && PROC_KCORE 1639 1640config ILLEGAL_POINTER_VALUE 1641 hex 1642 default 0 if X86_32 1643 default 0xdead000000000000 if X86_64 1644 1645config X86_PMEM_LEGACY_DEVICE 1646 bool 1647 1648config X86_PMEM_LEGACY 1649 tristate "Support non-standard NVDIMMs and ADR protected memory" 1650 depends on PHYS_ADDR_T_64BIT 1651 depends on BLK_DEV 1652 select X86_PMEM_LEGACY_DEVICE 1653 select NUMA_KEEP_MEMINFO if NUMA 1654 select LIBNVDIMM 1655 help 1656 Treat memory marked using the non-standard e820 type of 12 as used 1657 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1658 The kernel will offer these regions to the 'pmem' driver so 1659 they can be used for persistent storage. 1660 1661 Say Y if unsure. 1662 1663config HIGHPTE 1664 bool "Allocate 3rd-level pagetables from highmem" 1665 depends on HIGHMEM 1666 help 1667 The VM uses one page table entry for each page of physical memory. 1668 For systems with a lot of RAM, this can be wasteful of precious 1669 low memory. Setting this option will put user-space page table 1670 entries in high memory. 1671 1672config X86_CHECK_BIOS_CORRUPTION 1673 bool "Check for low memory corruption" 1674 help 1675 Periodically check for memory corruption in low memory, which 1676 is suspected to be caused by BIOS. Even when enabled in the 1677 configuration, it is disabled at runtime. Enable it by 1678 setting "memory_corruption_check=1" on the kernel command 1679 line. By default it scans the low 64k of memory every 60 1680 seconds; see the memory_corruption_check_size and 1681 memory_corruption_check_period parameters in 1682 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1683 1684 When enabled with the default parameters, this option has 1685 almost no overhead, as it reserves a relatively small amount 1686 of memory and scans it infrequently. It both detects corruption 1687 and prevents it from affecting the running system. 1688 1689 It is, however, intended as a diagnostic tool; if repeatable 1690 BIOS-originated corruption always affects the same memory, 1691 you can use memmap= to prevent the kernel from using that 1692 memory. 1693 1694config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1695 bool "Set the default setting of memory_corruption_check" 1696 depends on X86_CHECK_BIOS_CORRUPTION 1697 default y 1698 help 1699 Set whether the default state of memory_corruption_check is 1700 on or off. 1701 1702config MATH_EMULATION 1703 bool 1704 depends on MODIFY_LDT_SYSCALL 1705 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1706 help 1707 Linux can emulate a math coprocessor (used for floating point 1708 operations) if you don't have one. 486DX and Pentium processors have 1709 a math coprocessor built in, 486SX and 386 do not, unless you added 1710 a 487DX or 387, respectively. (The messages during boot time can 1711 give you some hints here ["man dmesg"].) Everyone needs either a 1712 coprocessor or this emulation. 1713 1714 If you don't have a math coprocessor, you need to say Y here; if you 1715 say Y here even though you have a coprocessor, the coprocessor will 1716 be used nevertheless. (This behavior can be changed with the kernel 1717 command line option "no387", which comes handy if your coprocessor 1718 is broken. Try "man bootparam" or see the documentation of your boot 1719 loader (lilo or loadlin) about how to pass options to the kernel at 1720 boot time.) This means that it is a good idea to say Y here if you 1721 intend to use this kernel on different machines. 1722 1723 More information about the internals of the Linux math coprocessor 1724 emulation can be found in <file:arch/x86/math-emu/README>. 1725 1726 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1727 kernel, it won't hurt. 1728 1729config MTRR 1730 def_bool y 1731 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1732 help 1733 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1734 the Memory Type Range Registers (MTRRs) may be used to control 1735 processor access to memory ranges. This is most useful if you have 1736 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1737 allows bus write transfers to be combined into a larger transfer 1738 before bursting over the PCI/AGP bus. This can increase performance 1739 of image write operations 2.5 times or more. Saying Y here creates a 1740 /proc/mtrr file which may be used to manipulate your processor's 1741 MTRRs. Typically the X server should use this. 1742 1743 This code has a reasonably generic interface so that similar 1744 control registers on other processors can be easily supported 1745 as well: 1746 1747 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1748 Registers (ARRs) which provide a similar functionality to MTRRs. For 1749 these, the ARRs are used to emulate the MTRRs. 1750 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1751 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1752 write-combining. All of these processors are supported by this code 1753 and it makes sense to say Y here if you have one of them. 1754 1755 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1756 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1757 can lead to all sorts of problems, so it's good to say Y here. 1758 1759 You can safely say Y even if your machine doesn't have MTRRs, you'll 1760 just add about 9 KB to your kernel. 1761 1762 See <file:Documentation/x86/mtrr.rst> for more information. 1763 1764config MTRR_SANITIZER 1765 def_bool y 1766 prompt "MTRR cleanup support" 1767 depends on MTRR 1768 help 1769 Convert MTRR layout from continuous to discrete, so X drivers can 1770 add writeback entries. 1771 1772 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1773 The largest mtrr entry size for a continuous block can be set with 1774 mtrr_chunk_size. 1775 1776 If unsure, say Y. 1777 1778config MTRR_SANITIZER_ENABLE_DEFAULT 1779 int "MTRR cleanup enable value (0-1)" 1780 range 0 1 1781 default "0" 1782 depends on MTRR_SANITIZER 1783 help 1784 Enable mtrr cleanup default value 1785 1786config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1787 int "MTRR cleanup spare reg num (0-7)" 1788 range 0 7 1789 default "1" 1790 depends on MTRR_SANITIZER 1791 help 1792 mtrr cleanup spare entries default, it can be changed via 1793 mtrr_spare_reg_nr=N on the kernel command line. 1794 1795config X86_PAT 1796 def_bool y 1797 prompt "x86 PAT support" if EXPERT 1798 depends on MTRR 1799 help 1800 Use PAT attributes to setup page level cache control. 1801 1802 PATs are the modern equivalents of MTRRs and are much more 1803 flexible than MTRRs. 1804 1805 Say N here if you see bootup problems (boot crash, boot hang, 1806 spontaneous reboots) or a non-working video driver. 1807 1808 If unsure, say Y. 1809 1810config ARCH_USES_PG_UNCACHED 1811 def_bool y 1812 depends on X86_PAT 1813 1814config ARCH_RANDOM 1815 def_bool y 1816 prompt "x86 architectural random number generator" if EXPERT 1817 help 1818 Enable the x86 architectural RDRAND instruction 1819 (Intel Bull Mountain technology) to generate random numbers. 1820 If supported, this is a high bandwidth, cryptographically 1821 secure hardware random number generator. 1822 1823config X86_SMAP 1824 def_bool y 1825 prompt "Supervisor Mode Access Prevention" if EXPERT 1826 help 1827 Supervisor Mode Access Prevention (SMAP) is a security 1828 feature in newer Intel processors. There is a small 1829 performance cost if this enabled and turned on; there is 1830 also a small increase in the kernel size if this is enabled. 1831 1832 If unsure, say Y. 1833 1834config X86_UMIP 1835 def_bool y 1836 prompt "User Mode Instruction Prevention" if EXPERT 1837 help 1838 User Mode Instruction Prevention (UMIP) is a security feature in 1839 some x86 processors. If enabled, a general protection fault is 1840 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1841 executed in user mode. These instructions unnecessarily expose 1842 information about the hardware state. 1843 1844 The vast majority of applications do not use these instructions. 1845 For the very few that do, software emulation is provided in 1846 specific cases in protected and virtual-8086 modes. Emulated 1847 results are dummy. 1848 1849config X86_INTEL_MEMORY_PROTECTION_KEYS 1850 prompt "Memory Protection Keys" 1851 def_bool y 1852 # Note: only available in 64-bit mode 1853 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1854 select ARCH_USES_HIGH_VMA_FLAGS 1855 select ARCH_HAS_PKEYS 1856 help 1857 Memory Protection Keys provides a mechanism for enforcing 1858 page-based protections, but without requiring modification of the 1859 page tables when an application changes protection domains. 1860 1861 For details, see Documentation/core-api/protection-keys.rst 1862 1863 If unsure, say y. 1864 1865choice 1866 prompt "TSX enable mode" 1867 depends on CPU_SUP_INTEL 1868 default X86_INTEL_TSX_MODE_OFF 1869 help 1870 Intel's TSX (Transactional Synchronization Extensions) feature 1871 allows to optimize locking protocols through lock elision which 1872 can lead to a noticeable performance boost. 1873 1874 On the other hand it has been shown that TSX can be exploited 1875 to form side channel attacks (e.g. TAA) and chances are there 1876 will be more of those attacks discovered in the future. 1877 1878 Therefore TSX is not enabled by default (aka tsx=off). An admin 1879 might override this decision by tsx=on the command line parameter. 1880 Even with TSX enabled, the kernel will attempt to enable the best 1881 possible TAA mitigation setting depending on the microcode available 1882 for the particular machine. 1883 1884 This option allows to set the default tsx mode between tsx=on, =off 1885 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1886 details. 1887 1888 Say off if not sure, auto if TSX is in use but it should be used on safe 1889 platforms or on if TSX is in use and the security aspect of tsx is not 1890 relevant. 1891 1892config X86_INTEL_TSX_MODE_OFF 1893 bool "off" 1894 help 1895 TSX is disabled if possible - equals to tsx=off command line parameter. 1896 1897config X86_INTEL_TSX_MODE_ON 1898 bool "on" 1899 help 1900 TSX is always enabled on TSX capable HW - equals the tsx=on command 1901 line parameter. 1902 1903config X86_INTEL_TSX_MODE_AUTO 1904 bool "auto" 1905 help 1906 TSX is enabled on TSX capable HW that is believed to be safe against 1907 side channel attacks- equals the tsx=auto command line parameter. 1908endchoice 1909 1910config X86_SGX 1911 bool "Software Guard eXtensions (SGX)" 1912 depends on X86_64 && CPU_SUP_INTEL 1913 depends on CRYPTO=y 1914 depends on CRYPTO_SHA256=y 1915 select SRCU 1916 select MMU_NOTIFIER 1917 select NUMA_KEEP_MEMINFO if NUMA 1918 help 1919 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1920 that can be used by applications to set aside private regions of code 1921 and data, referred to as enclaves. An enclave's private memory can 1922 only be accessed by code running within the enclave. Accesses from 1923 outside the enclave, including other enclaves, are disallowed by 1924 hardware. 1925 1926 If unsure, say N. 1927 1928config EFI 1929 bool "EFI runtime service support" 1930 depends on ACPI 1931 select UCS2_STRING 1932 select EFI_RUNTIME_WRAPPERS 1933 help 1934 This enables the kernel to use EFI runtime services that are 1935 available (such as the EFI variable services). 1936 1937 This option is only useful on systems that have EFI firmware. 1938 In addition, you should use the latest ELILO loader available 1939 at <http://elilo.sourceforge.net> in order to take advantage 1940 of EFI runtime services. However, even with this option, the 1941 resultant kernel should continue to boot on existing non-EFI 1942 platforms. 1943 1944config EFI_STUB 1945 bool "EFI stub support" 1946 depends on EFI && !X86_USE_3DNOW 1947 depends on $(cc-option,-mabi=ms) || X86_32 1948 select RELOCATABLE 1949 help 1950 This kernel feature allows a bzImage to be loaded directly 1951 by EFI firmware without the use of a bootloader. 1952 1953 See Documentation/admin-guide/efi-stub.rst for more information. 1954 1955config EFI_MIXED 1956 bool "EFI mixed-mode support" 1957 depends on EFI_STUB && X86_64 1958 help 1959 Enabling this feature allows a 64-bit kernel to be booted 1960 on a 32-bit firmware, provided that your CPU supports 64-bit 1961 mode. 1962 1963 Note that it is not possible to boot a mixed-mode enabled 1964 kernel via the EFI boot stub - a bootloader that supports 1965 the EFI handover protocol must be used. 1966 1967 If unsure, say N. 1968 1969source "kernel/Kconfig.hz" 1970 1971config KEXEC 1972 bool "kexec system call" 1973 select KEXEC_CORE 1974 help 1975 kexec is a system call that implements the ability to shutdown your 1976 current kernel, and to start another kernel. It is like a reboot 1977 but it is independent of the system firmware. And like a reboot 1978 you can start any kernel with it, not just Linux. 1979 1980 The name comes from the similarity to the exec system call. 1981 1982 It is an ongoing process to be certain the hardware in a machine 1983 is properly shutdown, so do not be surprised if this code does not 1984 initially work for you. As of this writing the exact hardware 1985 interface is strongly in flux, so no good recommendation can be 1986 made. 1987 1988config KEXEC_FILE 1989 bool "kexec file based system call" 1990 select KEXEC_CORE 1991 select BUILD_BIN2C 1992 depends on X86_64 1993 depends on CRYPTO=y 1994 depends on CRYPTO_SHA256=y 1995 help 1996 This is new version of kexec system call. This system call is 1997 file based and takes file descriptors as system call argument 1998 for kernel and initramfs as opposed to list of segments as 1999 accepted by previous system call. 2000 2001config ARCH_HAS_KEXEC_PURGATORY 2002 def_bool KEXEC_FILE 2003 2004config KEXEC_SIG 2005 bool "Verify kernel signature during kexec_file_load() syscall" 2006 depends on KEXEC_FILE 2007 help 2008 2009 This option makes the kexec_file_load() syscall check for a valid 2010 signature of the kernel image. The image can still be loaded without 2011 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2012 there's a signature that we can check, then it must be valid. 2013 2014 In addition to this option, you need to enable signature 2015 verification for the corresponding kernel image type being 2016 loaded in order for this to work. 2017 2018config KEXEC_SIG_FORCE 2019 bool "Require a valid signature in kexec_file_load() syscall" 2020 depends on KEXEC_SIG 2021 help 2022 This option makes kernel signature verification mandatory for 2023 the kexec_file_load() syscall. 2024 2025config KEXEC_BZIMAGE_VERIFY_SIG 2026 bool "Enable bzImage signature verification support" 2027 depends on KEXEC_SIG 2028 depends on SIGNED_PE_FILE_VERIFICATION 2029 select SYSTEM_TRUSTED_KEYRING 2030 help 2031 Enable bzImage signature verification support. 2032 2033config CRASH_DUMP 2034 bool "kernel crash dumps" 2035 depends on X86_64 || (X86_32 && HIGHMEM) 2036 help 2037 Generate crash dump after being started by kexec. 2038 This should be normally only set in special crash dump kernels 2039 which are loaded in the main kernel with kexec-tools into 2040 a specially reserved region and then later executed after 2041 a crash by kdump/kexec. The crash dump kernel must be compiled 2042 to a memory address not used by the main kernel or BIOS using 2043 PHYSICAL_START, or it must be built as a relocatable image 2044 (CONFIG_RELOCATABLE=y). 2045 For more details see Documentation/admin-guide/kdump/kdump.rst 2046 2047config KEXEC_JUMP 2048 bool "kexec jump" 2049 depends on KEXEC && HIBERNATION 2050 help 2051 Jump between original kernel and kexeced kernel and invoke 2052 code in physical address mode via KEXEC 2053 2054config PHYSICAL_START 2055 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2056 default "0x1000000" 2057 help 2058 This gives the physical address where the kernel is loaded. 2059 2060 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2061 bzImage will decompress itself to above physical address and 2062 run from there. Otherwise, bzImage will run from the address where 2063 it has been loaded by the boot loader and will ignore above physical 2064 address. 2065 2066 In normal kdump cases one does not have to set/change this option 2067 as now bzImage can be compiled as a completely relocatable image 2068 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2069 address. This option is mainly useful for the folks who don't want 2070 to use a bzImage for capturing the crash dump and want to use a 2071 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2072 to be specifically compiled to run from a specific memory area 2073 (normally a reserved region) and this option comes handy. 2074 2075 So if you are using bzImage for capturing the crash dump, 2076 leave the value here unchanged to 0x1000000 and set 2077 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2078 for capturing the crash dump change this value to start of 2079 the reserved region. In other words, it can be set based on 2080 the "X" value as specified in the "crashkernel=YM@XM" 2081 command line boot parameter passed to the panic-ed 2082 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2083 for more details about crash dumps. 2084 2085 Usage of bzImage for capturing the crash dump is recommended as 2086 one does not have to build two kernels. Same kernel can be used 2087 as production kernel and capture kernel. Above option should have 2088 gone away after relocatable bzImage support is introduced. But it 2089 is present because there are users out there who continue to use 2090 vmlinux for dump capture. This option should go away down the 2091 line. 2092 2093 Don't change this unless you know what you are doing. 2094 2095config RELOCATABLE 2096 bool "Build a relocatable kernel" 2097 default y 2098 help 2099 This builds a kernel image that retains relocation information 2100 so it can be loaded someplace besides the default 1MB. 2101 The relocations tend to make the kernel binary about 10% larger, 2102 but are discarded at runtime. 2103 2104 One use is for the kexec on panic case where the recovery kernel 2105 must live at a different physical address than the primary 2106 kernel. 2107 2108 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2109 it has been loaded at and the compile time physical address 2110 (CONFIG_PHYSICAL_START) is used as the minimum location. 2111 2112config RANDOMIZE_BASE 2113 bool "Randomize the address of the kernel image (KASLR)" 2114 depends on RELOCATABLE 2115 default y 2116 help 2117 In support of Kernel Address Space Layout Randomization (KASLR), 2118 this randomizes the physical address at which the kernel image 2119 is decompressed and the virtual address where the kernel 2120 image is mapped, as a security feature that deters exploit 2121 attempts relying on knowledge of the location of kernel 2122 code internals. 2123 2124 On 64-bit, the kernel physical and virtual addresses are 2125 randomized separately. The physical address will be anywhere 2126 between 16MB and the top of physical memory (up to 64TB). The 2127 virtual address will be randomized from 16MB up to 1GB (9 bits 2128 of entropy). Note that this also reduces the memory space 2129 available to kernel modules from 1.5GB to 1GB. 2130 2131 On 32-bit, the kernel physical and virtual addresses are 2132 randomized together. They will be randomized from 16MB up to 2133 512MB (8 bits of entropy). 2134 2135 Entropy is generated using the RDRAND instruction if it is 2136 supported. If RDTSC is supported, its value is mixed into 2137 the entropy pool as well. If neither RDRAND nor RDTSC are 2138 supported, then entropy is read from the i8254 timer. The 2139 usable entropy is limited by the kernel being built using 2140 2GB addressing, and that PHYSICAL_ALIGN must be at a 2141 minimum of 2MB. As a result, only 10 bits of entropy are 2142 theoretically possible, but the implementations are further 2143 limited due to memory layouts. 2144 2145 If unsure, say Y. 2146 2147# Relocation on x86 needs some additional build support 2148config X86_NEED_RELOCS 2149 def_bool y 2150 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2151 2152config PHYSICAL_ALIGN 2153 hex "Alignment value to which kernel should be aligned" 2154 default "0x200000" 2155 range 0x2000 0x1000000 if X86_32 2156 range 0x200000 0x1000000 if X86_64 2157 help 2158 This value puts the alignment restrictions on physical address 2159 where kernel is loaded and run from. Kernel is compiled for an 2160 address which meets above alignment restriction. 2161 2162 If bootloader loads the kernel at a non-aligned address and 2163 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2164 address aligned to above value and run from there. 2165 2166 If bootloader loads the kernel at a non-aligned address and 2167 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2168 load address and decompress itself to the address it has been 2169 compiled for and run from there. The address for which kernel is 2170 compiled already meets above alignment restrictions. Hence the 2171 end result is that kernel runs from a physical address meeting 2172 above alignment restrictions. 2173 2174 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2175 this value must be a multiple of 0x200000. 2176 2177 Don't change this unless you know what you are doing. 2178 2179config DYNAMIC_MEMORY_LAYOUT 2180 bool 2181 help 2182 This option makes base addresses of vmalloc and vmemmap as well as 2183 __PAGE_OFFSET movable during boot. 2184 2185config RANDOMIZE_MEMORY 2186 bool "Randomize the kernel memory sections" 2187 depends on X86_64 2188 depends on RANDOMIZE_BASE 2189 select DYNAMIC_MEMORY_LAYOUT 2190 default RANDOMIZE_BASE 2191 help 2192 Randomizes the base virtual address of kernel memory sections 2193 (physical memory mapping, vmalloc & vmemmap). This security feature 2194 makes exploits relying on predictable memory locations less reliable. 2195 2196 The order of allocations remains unchanged. Entropy is generated in 2197 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2198 configuration have in average 30,000 different possible virtual 2199 addresses for each memory section. 2200 2201 If unsure, say Y. 2202 2203config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2204 hex "Physical memory mapping padding" if EXPERT 2205 depends on RANDOMIZE_MEMORY 2206 default "0xa" if MEMORY_HOTPLUG 2207 default "0x0" 2208 range 0x1 0x40 if MEMORY_HOTPLUG 2209 range 0x0 0x40 2210 help 2211 Define the padding in terabytes added to the existing physical 2212 memory size during kernel memory randomization. It is useful 2213 for memory hotplug support but reduces the entropy available for 2214 address randomization. 2215 2216 If unsure, leave at the default value. 2217 2218config HOTPLUG_CPU 2219 def_bool y 2220 depends on SMP 2221 2222config BOOTPARAM_HOTPLUG_CPU0 2223 bool "Set default setting of cpu0_hotpluggable" 2224 depends on HOTPLUG_CPU 2225 help 2226 Set whether default state of cpu0_hotpluggable is on or off. 2227 2228 Say Y here to enable CPU0 hotplug by default. If this switch 2229 is turned on, there is no need to give cpu0_hotplug kernel 2230 parameter and the CPU0 hotplug feature is enabled by default. 2231 2232 Please note: there are two known CPU0 dependencies if you want 2233 to enable the CPU0 hotplug feature either by this switch or by 2234 cpu0_hotplug kernel parameter. 2235 2236 First, resume from hibernate or suspend always starts from CPU0. 2237 So hibernate and suspend are prevented if CPU0 is offline. 2238 2239 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2240 offline if any interrupt can not migrate out of CPU0. There may 2241 be other CPU0 dependencies. 2242 2243 Please make sure the dependencies are under your control before 2244 you enable this feature. 2245 2246 Say N if you don't want to enable CPU0 hotplug feature by default. 2247 You still can enable the CPU0 hotplug feature at boot by kernel 2248 parameter cpu0_hotplug. 2249 2250config DEBUG_HOTPLUG_CPU0 2251 def_bool n 2252 prompt "Debug CPU0 hotplug" 2253 depends on HOTPLUG_CPU 2254 help 2255 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2256 soon as possible and boots up userspace with CPU0 offlined. User 2257 can online CPU0 back after boot time. 2258 2259 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2260 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2261 compilation or giving cpu0_hotplug kernel parameter at boot. 2262 2263 If unsure, say N. 2264 2265config COMPAT_VDSO 2266 def_bool n 2267 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2268 depends on COMPAT_32 2269 help 2270 Certain buggy versions of glibc will crash if they are 2271 presented with a 32-bit vDSO that is not mapped at the address 2272 indicated in its segment table. 2273 2274 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2275 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2276 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2277 the only released version with the bug, but OpenSUSE 9 2278 contains a buggy "glibc 2.3.2". 2279 2280 The symptom of the bug is that everything crashes on startup, saying: 2281 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2282 2283 Saying Y here changes the default value of the vdso32 boot 2284 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2285 This works around the glibc bug but hurts performance. 2286 2287 If unsure, say N: if you are compiling your own kernel, you 2288 are unlikely to be using a buggy version of glibc. 2289 2290choice 2291 prompt "vsyscall table for legacy applications" 2292 depends on X86_64 2293 default LEGACY_VSYSCALL_XONLY 2294 help 2295 Legacy user code that does not know how to find the vDSO expects 2296 to be able to issue three syscalls by calling fixed addresses in 2297 kernel space. Since this location is not randomized with ASLR, 2298 it can be used to assist security vulnerability exploitation. 2299 2300 This setting can be changed at boot time via the kernel command 2301 line parameter vsyscall=[emulate|xonly|none]. 2302 2303 On a system with recent enough glibc (2.14 or newer) and no 2304 static binaries, you can say None without a performance penalty 2305 to improve security. 2306 2307 If unsure, select "Emulate execution only". 2308 2309 config LEGACY_VSYSCALL_EMULATE 2310 bool "Full emulation" 2311 help 2312 The kernel traps and emulates calls into the fixed vsyscall 2313 address mapping. This makes the mapping non-executable, but 2314 it still contains readable known contents, which could be 2315 used in certain rare security vulnerability exploits. This 2316 configuration is recommended when using legacy userspace 2317 that still uses vsyscalls along with legacy binary 2318 instrumentation tools that require code to be readable. 2319 2320 An example of this type of legacy userspace is running 2321 Pin on an old binary that still uses vsyscalls. 2322 2323 config LEGACY_VSYSCALL_XONLY 2324 bool "Emulate execution only" 2325 help 2326 The kernel traps and emulates calls into the fixed vsyscall 2327 address mapping and does not allow reads. This 2328 configuration is recommended when userspace might use the 2329 legacy vsyscall area but support for legacy binary 2330 instrumentation of legacy code is not needed. It mitigates 2331 certain uses of the vsyscall area as an ASLR-bypassing 2332 buffer. 2333 2334 config LEGACY_VSYSCALL_NONE 2335 bool "None" 2336 help 2337 There will be no vsyscall mapping at all. This will 2338 eliminate any risk of ASLR bypass due to the vsyscall 2339 fixed address mapping. Attempts to use the vsyscalls 2340 will be reported to dmesg, so that either old or 2341 malicious userspace programs can be identified. 2342 2343endchoice 2344 2345config CMDLINE_BOOL 2346 bool "Built-in kernel command line" 2347 help 2348 Allow for specifying boot arguments to the kernel at 2349 build time. On some systems (e.g. embedded ones), it is 2350 necessary or convenient to provide some or all of the 2351 kernel boot arguments with the kernel itself (that is, 2352 to not rely on the boot loader to provide them.) 2353 2354 To compile command line arguments into the kernel, 2355 set this option to 'Y', then fill in the 2356 boot arguments in CONFIG_CMDLINE. 2357 2358 Systems with fully functional boot loaders (i.e. non-embedded) 2359 should leave this option set to 'N'. 2360 2361config CMDLINE 2362 string "Built-in kernel command string" 2363 depends on CMDLINE_BOOL 2364 default "" 2365 help 2366 Enter arguments here that should be compiled into the kernel 2367 image and used at boot time. If the boot loader provides a 2368 command line at boot time, it is appended to this string to 2369 form the full kernel command line, when the system boots. 2370 2371 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2372 change this behavior. 2373 2374 In most cases, the command line (whether built-in or provided 2375 by the boot loader) should specify the device for the root 2376 file system. 2377 2378config CMDLINE_OVERRIDE 2379 bool "Built-in command line overrides boot loader arguments" 2380 depends on CMDLINE_BOOL && CMDLINE != "" 2381 help 2382 Set this option to 'Y' to have the kernel ignore the boot loader 2383 command line, and use ONLY the built-in command line. 2384 2385 This is used to work around broken boot loaders. This should 2386 be set to 'N' under normal conditions. 2387 2388config MODIFY_LDT_SYSCALL 2389 bool "Enable the LDT (local descriptor table)" if EXPERT 2390 default y 2391 help 2392 Linux can allow user programs to install a per-process x86 2393 Local Descriptor Table (LDT) using the modify_ldt(2) system 2394 call. This is required to run 16-bit or segmented code such as 2395 DOSEMU or some Wine programs. It is also used by some very old 2396 threading libraries. 2397 2398 Enabling this feature adds a small amount of overhead to 2399 context switches and increases the low-level kernel attack 2400 surface. Disabling it removes the modify_ldt(2) system call. 2401 2402 Saying 'N' here may make sense for embedded or server kernels. 2403 2404config STRICT_SIGALTSTACK_SIZE 2405 bool "Enforce strict size checking for sigaltstack" 2406 depends on DYNAMIC_SIGFRAME 2407 help 2408 For historical reasons MINSIGSTKSZ is a constant which became 2409 already too small with AVX512 support. Add a mechanism to 2410 enforce strict checking of the sigaltstack size against the 2411 real size of the FPU frame. This option enables the check 2412 by default. It can also be controlled via the kernel command 2413 line option 'strict_sas_size' independent of this config 2414 switch. Enabling it might break existing applications which 2415 allocate a too small sigaltstack but 'work' because they 2416 never get a signal delivered. 2417 2418 Say 'N' unless you want to really enforce this check. 2419 2420source "kernel/livepatch/Kconfig" 2421 2422endmenu 2423 2424config ARCH_HAS_ADD_PAGES 2425 def_bool y 2426 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 2427 2428config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 2429 def_bool y 2430 2431config USE_PERCPU_NUMA_NODE_ID 2432 def_bool y 2433 depends on NUMA 2434 2435menu "Power management and ACPI options" 2436 2437config ARCH_HIBERNATION_HEADER 2438 def_bool y 2439 depends on HIBERNATION 2440 2441source "kernel/power/Kconfig" 2442 2443source "drivers/acpi/Kconfig" 2444 2445config X86_APM_BOOT 2446 def_bool y 2447 depends on APM 2448 2449menuconfig APM 2450 tristate "APM (Advanced Power Management) BIOS support" 2451 depends on X86_32 && PM_SLEEP 2452 help 2453 APM is a BIOS specification for saving power using several different 2454 techniques. This is mostly useful for battery powered laptops with 2455 APM compliant BIOSes. If you say Y here, the system time will be 2456 reset after a RESUME operation, the /proc/apm device will provide 2457 battery status information, and user-space programs will receive 2458 notification of APM "events" (e.g. battery status change). 2459 2460 If you select "Y" here, you can disable actual use of the APM 2461 BIOS by passing the "apm=off" option to the kernel at boot time. 2462 2463 Note that the APM support is almost completely disabled for 2464 machines with more than one CPU. 2465 2466 In order to use APM, you will need supporting software. For location 2467 and more information, read <file:Documentation/power/apm-acpi.rst> 2468 and the Battery Powered Linux mini-HOWTO, available from 2469 <http://www.tldp.org/docs.html#howto>. 2470 2471 This driver does not spin down disk drives (see the hdparm(8) 2472 manpage ("man 8 hdparm") for that), and it doesn't turn off 2473 VESA-compliant "green" monitors. 2474 2475 This driver does not support the TI 4000M TravelMate and the ACER 2476 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2477 desktop machines also don't have compliant BIOSes, and this driver 2478 may cause those machines to panic during the boot phase. 2479 2480 Generally, if you don't have a battery in your machine, there isn't 2481 much point in using this driver and you should say N. If you get 2482 random kernel OOPSes or reboots that don't seem to be related to 2483 anything, try disabling/enabling this option (or disabling/enabling 2484 APM in your BIOS). 2485 2486 Some other things you should try when experiencing seemingly random, 2487 "weird" problems: 2488 2489 1) make sure that you have enough swap space and that it is 2490 enabled. 2491 2) pass the "no-hlt" option to the kernel 2492 3) switch on floating point emulation in the kernel and pass 2493 the "no387" option to the kernel 2494 4) pass the "floppy=nodma" option to the kernel 2495 5) pass the "mem=4M" option to the kernel (thereby disabling 2496 all but the first 4 MB of RAM) 2497 6) make sure that the CPU is not over clocked. 2498 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2499 8) disable the cache from your BIOS settings 2500 9) install a fan for the video card or exchange video RAM 2501 10) install a better fan for the CPU 2502 11) exchange RAM chips 2503 12) exchange the motherboard. 2504 2505 To compile this driver as a module, choose M here: the 2506 module will be called apm. 2507 2508if APM 2509 2510config APM_IGNORE_USER_SUSPEND 2511 bool "Ignore USER SUSPEND" 2512 help 2513 This option will ignore USER SUSPEND requests. On machines with a 2514 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2515 series notebooks, it is necessary to say Y because of a BIOS bug. 2516 2517config APM_DO_ENABLE 2518 bool "Enable PM at boot time" 2519 help 2520 Enable APM features at boot time. From page 36 of the APM BIOS 2521 specification: "When disabled, the APM BIOS does not automatically 2522 power manage devices, enter the Standby State, enter the Suspend 2523 State, or take power saving steps in response to CPU Idle calls." 2524 This driver will make CPU Idle calls when Linux is idle (unless this 2525 feature is turned off -- see "Do CPU IDLE calls", below). This 2526 should always save battery power, but more complicated APM features 2527 will be dependent on your BIOS implementation. You may need to turn 2528 this option off if your computer hangs at boot time when using APM 2529 support, or if it beeps continuously instead of suspending. Turn 2530 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2531 T400CDT. This is off by default since most machines do fine without 2532 this feature. 2533 2534config APM_CPU_IDLE 2535 depends on CPU_IDLE 2536 bool "Make CPU Idle calls when idle" 2537 help 2538 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2539 On some machines, this can activate improved power savings, such as 2540 a slowed CPU clock rate, when the machine is idle. These idle calls 2541 are made after the idle loop has run for some length of time (e.g., 2542 333 mS). On some machines, this will cause a hang at boot time or 2543 whenever the CPU becomes idle. (On machines with more than one CPU, 2544 this option does nothing.) 2545 2546config APM_DISPLAY_BLANK 2547 bool "Enable console blanking using APM" 2548 help 2549 Enable console blanking using the APM. Some laptops can use this to 2550 turn off the LCD backlight when the screen blanker of the Linux 2551 virtual console blanks the screen. Note that this is only used by 2552 the virtual console screen blanker, and won't turn off the backlight 2553 when using the X Window system. This also doesn't have anything to 2554 do with your VESA-compliant power-saving monitor. Further, this 2555 option doesn't work for all laptops -- it might not turn off your 2556 backlight at all, or it might print a lot of errors to the console, 2557 especially if you are using gpm. 2558 2559config APM_ALLOW_INTS 2560 bool "Allow interrupts during APM BIOS calls" 2561 help 2562 Normally we disable external interrupts while we are making calls to 2563 the APM BIOS as a measure to lessen the effects of a badly behaving 2564 BIOS implementation. The BIOS should reenable interrupts if it 2565 needs to. Unfortunately, some BIOSes do not -- especially those in 2566 many of the newer IBM Thinkpads. If you experience hangs when you 2567 suspend, try setting this to Y. Otherwise, say N. 2568 2569endif # APM 2570 2571source "drivers/cpufreq/Kconfig" 2572 2573source "drivers/cpuidle/Kconfig" 2574 2575source "drivers/idle/Kconfig" 2576 2577endmenu 2578 2579 2580menu "Bus options (PCI etc.)" 2581 2582choice 2583 prompt "PCI access mode" 2584 depends on X86_32 && PCI 2585 default PCI_GOANY 2586 help 2587 On PCI systems, the BIOS can be used to detect the PCI devices and 2588 determine their configuration. However, some old PCI motherboards 2589 have BIOS bugs and may crash if this is done. Also, some embedded 2590 PCI-based systems don't have any BIOS at all. Linux can also try to 2591 detect the PCI hardware directly without using the BIOS. 2592 2593 With this option, you can specify how Linux should detect the 2594 PCI devices. If you choose "BIOS", the BIOS will be used, 2595 if you choose "Direct", the BIOS won't be used, and if you 2596 choose "MMConfig", then PCI Express MMCONFIG will be used. 2597 If you choose "Any", the kernel will try MMCONFIG, then the 2598 direct access method and falls back to the BIOS if that doesn't 2599 work. If unsure, go with the default, which is "Any". 2600 2601config PCI_GOBIOS 2602 bool "BIOS" 2603 2604config PCI_GOMMCONFIG 2605 bool "MMConfig" 2606 2607config PCI_GODIRECT 2608 bool "Direct" 2609 2610config PCI_GOOLPC 2611 bool "OLPC XO-1" 2612 depends on OLPC 2613 2614config PCI_GOANY 2615 bool "Any" 2616 2617endchoice 2618 2619config PCI_BIOS 2620 def_bool y 2621 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2622 2623# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2624config PCI_DIRECT 2625 def_bool y 2626 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2627 2628config PCI_MMCONFIG 2629 bool "Support mmconfig PCI config space access" if X86_64 2630 default y 2631 depends on PCI && (ACPI || JAILHOUSE_GUEST) 2632 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2633 2634config PCI_OLPC 2635 def_bool y 2636 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2637 2638config PCI_XEN 2639 def_bool y 2640 depends on PCI && XEN 2641 2642config MMCONF_FAM10H 2643 def_bool y 2644 depends on X86_64 && PCI_MMCONFIG && ACPI 2645 2646config PCI_CNB20LE_QUIRK 2647 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2648 depends on PCI 2649 help 2650 Read the PCI windows out of the CNB20LE host bridge. This allows 2651 PCI hotplug to work on systems with the CNB20LE chipset which do 2652 not have ACPI. 2653 2654 There's no public spec for this chipset, and this functionality 2655 is known to be incomplete. 2656 2657 You should say N unless you know you need this. 2658 2659config ISA_BUS 2660 bool "ISA bus support on modern systems" if EXPERT 2661 help 2662 Expose ISA bus device drivers and options available for selection and 2663 configuration. Enable this option if your target machine has an ISA 2664 bus. ISA is an older system, displaced by PCI and newer bus 2665 architectures -- if your target machine is modern, it probably does 2666 not have an ISA bus. 2667 2668 If unsure, say N. 2669 2670# x86_64 have no ISA slots, but can have ISA-style DMA. 2671config ISA_DMA_API 2672 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2673 default y 2674 help 2675 Enables ISA-style DMA support for devices requiring such controllers. 2676 If unsure, say Y. 2677 2678if X86_32 2679 2680config ISA 2681 bool "ISA support" 2682 help 2683 Find out whether you have ISA slots on your motherboard. ISA is the 2684 name of a bus system, i.e. the way the CPU talks to the other stuff 2685 inside your box. Other bus systems are PCI, EISA, MicroChannel 2686 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2687 newer boards don't support it. If you have ISA, say Y, otherwise N. 2688 2689config SCx200 2690 tristate "NatSemi SCx200 support" 2691 help 2692 This provides basic support for National Semiconductor's 2693 (now AMD's) Geode processors. The driver probes for the 2694 PCI-IDs of several on-chip devices, so its a good dependency 2695 for other scx200_* drivers. 2696 2697 If compiled as a module, the driver is named scx200. 2698 2699config SCx200HR_TIMER 2700 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2701 depends on SCx200 2702 default y 2703 help 2704 This driver provides a clocksource built upon the on-chip 2705 27MHz high-resolution timer. Its also a workaround for 2706 NSC Geode SC-1100's buggy TSC, which loses time when the 2707 processor goes idle (as is done by the scheduler). The 2708 other workaround is idle=poll boot option. 2709 2710config OLPC 2711 bool "One Laptop Per Child support" 2712 depends on !X86_PAE 2713 select GPIOLIB 2714 select OF 2715 select OF_PROMTREE 2716 select IRQ_DOMAIN 2717 select OLPC_EC 2718 help 2719 Add support for detecting the unique features of the OLPC 2720 XO hardware. 2721 2722config OLPC_XO1_PM 2723 bool "OLPC XO-1 Power Management" 2724 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2725 help 2726 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2727 2728config OLPC_XO1_RTC 2729 bool "OLPC XO-1 Real Time Clock" 2730 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2731 help 2732 Add support for the XO-1 real time clock, which can be used as a 2733 programmable wakeup source. 2734 2735config OLPC_XO1_SCI 2736 bool "OLPC XO-1 SCI extras" 2737 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2738 depends on INPUT=y 2739 select POWER_SUPPLY 2740 help 2741 Add support for SCI-based features of the OLPC XO-1 laptop: 2742 - EC-driven system wakeups 2743 - Power button 2744 - Ebook switch 2745 - Lid switch 2746 - AC adapter status updates 2747 - Battery status updates 2748 2749config OLPC_XO15_SCI 2750 bool "OLPC XO-1.5 SCI extras" 2751 depends on OLPC && ACPI 2752 select POWER_SUPPLY 2753 help 2754 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2755 - EC-driven system wakeups 2756 - AC adapter status updates 2757 - Battery status updates 2758 2759config ALIX 2760 bool "PCEngines ALIX System Support (LED setup)" 2761 select GPIOLIB 2762 help 2763 This option enables system support for the PCEngines ALIX. 2764 At present this just sets up LEDs for GPIO control on 2765 ALIX2/3/6 boards. However, other system specific setup should 2766 get added here. 2767 2768 Note: You must still enable the drivers for GPIO and LED support 2769 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2770 2771 Note: You have to set alix.force=1 for boards with Award BIOS. 2772 2773config NET5501 2774 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2775 select GPIOLIB 2776 help 2777 This option enables system support for the Soekris Engineering net5501. 2778 2779config GEOS 2780 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2781 select GPIOLIB 2782 depends on DMI 2783 help 2784 This option enables system support for the Traverse Technologies GEOS. 2785 2786config TS5500 2787 bool "Technologic Systems TS-5500 platform support" 2788 depends on MELAN 2789 select CHECK_SIGNATURE 2790 select NEW_LEDS 2791 select LEDS_CLASS 2792 help 2793 This option enables system support for the Technologic Systems TS-5500. 2794 2795endif # X86_32 2796 2797config AMD_NB 2798 def_bool y 2799 depends on CPU_SUP_AMD && PCI 2800 2801endmenu 2802 2803 2804menu "Binary Emulations" 2805 2806config IA32_EMULATION 2807 bool "IA32 Emulation" 2808 depends on X86_64 2809 select ARCH_WANT_OLD_COMPAT_IPC 2810 select BINFMT_ELF 2811 select COMPAT_OLD_SIGACTION 2812 help 2813 Include code to run legacy 32-bit programs under a 2814 64-bit kernel. You should likely turn this on, unless you're 2815 100% sure that you don't have any 32-bit programs left. 2816 2817config IA32_AOUT 2818 tristate "IA32 a.out support" 2819 depends on IA32_EMULATION 2820 depends on BROKEN 2821 help 2822 Support old a.out binaries in the 32bit emulation. 2823 2824config X86_X32 2825 bool "x32 ABI for 64-bit mode" 2826 depends on X86_64 2827 help 2828 Include code to run binaries for the x32 native 32-bit ABI 2829 for 64-bit processors. An x32 process gets access to the 2830 full 64-bit register file and wide data path while leaving 2831 pointers at 32 bits for smaller memory footprint. 2832 2833 You will need a recent binutils (2.22 or later) with 2834 elf32_x86_64 support enabled to compile a kernel with this 2835 option set. 2836 2837config COMPAT_32 2838 def_bool y 2839 depends on IA32_EMULATION || X86_32 2840 select HAVE_UID16 2841 select OLD_SIGSUSPEND3 2842 2843config COMPAT 2844 def_bool y 2845 depends on IA32_EMULATION || X86_X32 2846 2847if COMPAT 2848config COMPAT_FOR_U64_ALIGNMENT 2849 def_bool y 2850 2851config SYSVIPC_COMPAT 2852 def_bool y 2853 depends on SYSVIPC 2854endif 2855 2856endmenu 2857 2858 2859config HAVE_ATOMIC_IOMAP 2860 def_bool y 2861 depends on X86_32 2862 2863source "arch/x86/kvm/Kconfig" 2864 2865source "arch/x86/Kconfig.assembler" 2866