1# SPDX-License-Identifier: GPL-2.0 2# Select 32 or 64 bit 3config 64BIT 4 bool "64-bit kernel" if "$(ARCH)" = "x86" 5 default "$(ARCH)" != "i386" 6 help 7 Say yes to build a 64-bit kernel - formerly known as x86_64 8 Say no to build a 32-bit kernel - formerly known as i386 9 10config X86_32 11 def_bool y 12 depends on !64BIT 13 # Options that are inherently 32-bit kernel only: 14 select ARCH_WANT_IPC_PARSE_VERSION 15 select CLKSRC_I8253 16 select CLONE_BACKWARDS 17 select GENERIC_VDSO_32 18 select HAVE_DEBUG_STACKOVERFLOW 19 select KMAP_LOCAL 20 select MODULES_USE_ELF_REL 21 select OLD_SIGACTION 22 select ARCH_SPLIT_ARG64 23 24config X86_64 25 def_bool y 26 depends on 64BIT 27 # Options that are inherently 64-bit kernel only: 28 select ARCH_HAS_GIGANTIC_PAGE 29 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 30 select ARCH_USE_CMPXCHG_LOCKREF 31 select HAVE_ARCH_SOFT_DIRTY 32 select MODULES_USE_ELF_RELA 33 select NEED_DMA_MAP_STATE 34 select SWIOTLB 35 select ARCH_HAS_ELFCORE_COMPAT 36 select ZONE_DMA32 37 38config FORCE_DYNAMIC_FTRACE 39 def_bool y 40 depends on X86_32 41 depends on FUNCTION_TRACER 42 select DYNAMIC_FTRACE 43 help 44 We keep the static function tracing (!DYNAMIC_FTRACE) around 45 in order to test the non static function tracing in the 46 generic code, as other architectures still use it. But we 47 only need to keep it around for x86_64. No need to keep it 48 for x86_32. For x86_32, force DYNAMIC_FTRACE. 49# 50# Arch settings 51# 52# ( Note that options that are marked 'if X86_64' could in principle be 53# ported to 32-bit as well. ) 54# 55config X86 56 def_bool y 57 # 58 # Note: keep this list sorted alphabetically 59 # 60 select ACPI_LEGACY_TABLES_LOOKUP if ACPI 61 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 62 select ARCH_32BIT_OFF_T if X86_32 63 select ARCH_CLOCKSOURCE_INIT 64 select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 65 select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION 66 select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64 67 select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG 68 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE) 69 select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE 70 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 71 select ARCH_HAS_CACHE_LINE_SIZE 72 select ARCH_HAS_DEBUG_VIRTUAL 73 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 74 select ARCH_HAS_DEVMEM_IS_ALLOWED 75 select ARCH_HAS_EARLY_DEBUG if KGDB 76 select ARCH_HAS_ELF_RANDOMIZE 77 select ARCH_HAS_FAST_MULTIPLIER 78 select ARCH_HAS_FILTER_PGPROT 79 select ARCH_HAS_FORTIFY_SOURCE 80 select ARCH_HAS_GCOV_PROFILE_ALL 81 select ARCH_HAS_KCOV if X86_64 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_PAGE_TABLE_CHECK if X86_64 108 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 109 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 110 select ARCH_SUPPORTS_LTO_CLANG 111 select ARCH_SUPPORTS_LTO_CLANG_THIN 112 select ARCH_USE_BUILTIN_BSWAP 113 select ARCH_USE_MEMTEST 114 select ARCH_USE_QUEUED_RWLOCKS 115 select ARCH_USE_QUEUED_SPINLOCKS 116 select ARCH_USE_SYM_ANNOTATIONS 117 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 118 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 119 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 120 select ARCH_WANTS_NO_INSTR 121 select ARCH_WANT_HUGE_PMD_SHARE 122 select ARCH_WANT_LD_ORPHAN_WARN 123 select ARCH_WANTS_THP_SWAP if X86_64 124 select ARCH_HAS_PARANOID_L1D_FLUSH 125 select BUILDTIME_TABLE_SORT 126 select CLKEVT_I8253 127 select CLOCKSOURCE_VALIDATE_LAST_CYCLE 128 select CLOCKSOURCE_WATCHDOG 129 select DCACHE_WORD_ACCESS 130 select DYNAMIC_SIGFRAME 131 select EDAC_ATOMIC_SCRUB 132 select EDAC_SUPPORT 133 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 134 select GENERIC_CLOCKEVENTS_MIN_ADJUST 135 select GENERIC_CMOS_UPDATE 136 select GENERIC_CPU_AUTOPROBE 137 select GENERIC_CPU_VULNERABILITIES 138 select GENERIC_EARLY_IOREMAP 139 select GENERIC_ENTRY 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_BUILDTIME_MCOUNT_SORT 190 select HAVE_DEBUG_KMEMLEAK 191 select HAVE_DMA_CONTIGUOUS 192 select HAVE_DYNAMIC_FTRACE 193 select HAVE_DYNAMIC_FTRACE_WITH_REGS 194 select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 195 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 196 select HAVE_SAMPLE_FTRACE_DIRECT if X86_64 197 select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64 198 select HAVE_EBPF_JIT 199 select HAVE_EFFICIENT_UNALIGNED_ACCESS 200 select HAVE_EISA 201 select HAVE_EXIT_THREAD 202 select HAVE_FAST_GUP 203 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 204 select HAVE_FTRACE_MCOUNT_RECORD 205 select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) 206 select HAVE_FUNCTION_TRACER 207 select HAVE_GCC_PLUGINS 208 select HAVE_HW_BREAKPOINT 209 select HAVE_IOREMAP_PROT 210 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 211 select HAVE_IRQ_TIME_ACCOUNTING 212 select HAVE_KERNEL_BZIP2 213 select HAVE_KERNEL_GZIP 214 select HAVE_KERNEL_LZ4 215 select HAVE_KERNEL_LZMA 216 select HAVE_KERNEL_LZO 217 select HAVE_KERNEL_XZ 218 select HAVE_KERNEL_ZSTD 219 select HAVE_KPROBES 220 select HAVE_KPROBES_ON_FTRACE 221 select HAVE_FUNCTION_ERROR_INJECTION 222 select HAVE_KRETPROBES 223 select HAVE_KVM 224 select HAVE_LIVEPATCH if X86_64 225 select HAVE_MIXED_BREAKPOINTS_REGS 226 select HAVE_MOD_ARCH_SPECIFIC 227 select HAVE_MOVE_PMD 228 select HAVE_MOVE_PUD 229 select HAVE_NMI 230 select HAVE_OPTPROBES 231 select HAVE_PCSPKR_PLATFORM 232 select HAVE_PERF_EVENTS 233 select HAVE_PERF_EVENTS_NMI 234 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 235 select HAVE_PCI 236 select HAVE_PERF_REGS 237 select HAVE_PERF_USER_STACK_DUMP 238 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 239 select HAVE_POSIX_CPU_TIMERS_TASK_WORK 240 select HAVE_REGS_AND_STACK_ACCESS_API 241 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 242 select HAVE_FUNCTION_ARG_ACCESS_API 243 select HAVE_SETUP_PER_CPU_AREA 244 select HAVE_SOFTIRQ_ON_OWN_STACK 245 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 246 select HAVE_STACK_VALIDATION if X86_64 247 select HAVE_STATIC_CALL 248 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION 249 select HAVE_PREEMPT_DYNAMIC 250 select HAVE_RSEQ 251 select HAVE_SYSCALL_TRACEPOINTS 252 select HAVE_UNSTABLE_SCHED_CLOCK 253 select HAVE_USER_RETURN_NOTIFIER 254 select HAVE_GENERIC_VDSO 255 select HOTPLUG_SMT if SMP 256 select IRQ_FORCED_THREADING 257 select NEED_PER_CPU_EMBED_FIRST_CHUNK 258 select NEED_PER_CPU_PAGE_FIRST_CHUNK 259 select NEED_SG_DMA_LENGTH 260 select PCI_DOMAINS if PCI 261 select PCI_LOCKLESS_CONFIG if PCI 262 select PERF_EVENTS 263 select RTC_LIB 264 select RTC_MC146818_LIB 265 select SPARSE_IRQ 266 select SRCU 267 select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE) 268 select SYSCTL_EXCEPTION_TRACE 269 select THREAD_INFO_IN_TASK 270 select TRACE_IRQFLAGS_SUPPORT 271 select USER_STACKTRACE_SUPPORT 272 select VIRT_TO_BUS 273 select HAVE_ARCH_KCSAN if X86_64 274 select X86_FEATURE_NAMES if PROC_FS 275 select PROC_PID_ARCH_STATUS if PROC_FS 276 select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX 277 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 278 279config INSTRUCTION_DECODER 280 def_bool y 281 depends on KPROBES || PERF_EVENTS || UPROBES 282 283config OUTPUT_FORMAT 284 string 285 default "elf32-i386" if X86_32 286 default "elf64-x86-64" if X86_64 287 288config LOCKDEP_SUPPORT 289 def_bool y 290 291config STACKTRACE_SUPPORT 292 def_bool y 293 294config MMU 295 def_bool y 296 297config ARCH_MMAP_RND_BITS_MIN 298 default 28 if 64BIT 299 default 8 300 301config ARCH_MMAP_RND_BITS_MAX 302 default 32 if 64BIT 303 default 16 304 305config ARCH_MMAP_RND_COMPAT_BITS_MIN 306 default 8 307 308config ARCH_MMAP_RND_COMPAT_BITS_MAX 309 default 16 310 311config SBUS 312 bool 313 314config GENERIC_ISA_DMA 315 def_bool y 316 depends on ISA_DMA_API 317 318config GENERIC_BUG 319 def_bool y 320 depends on BUG 321 select GENERIC_BUG_RELATIVE_POINTERS if X86_64 322 323config GENERIC_BUG_RELATIVE_POINTERS 324 bool 325 326config ARCH_MAY_HAVE_PC_FDC 327 def_bool y 328 depends on ISA_DMA_API 329 330config GENERIC_CALIBRATE_DELAY 331 def_bool y 332 333config ARCH_HAS_CPU_RELAX 334 def_bool y 335 336config ARCH_HAS_FILTER_PGPROT 337 def_bool y 338 339config ARCH_HIBERNATION_POSSIBLE 340 def_bool y 341 342config ARCH_NR_GPIO 343 int 344 default 1024 if X86_64 345 default 512 346 347config ARCH_SUSPEND_POSSIBLE 348 def_bool y 349 350config ARCH_WANT_GENERAL_HUGETLB 351 def_bool y 352 353config AUDIT_ARCH 354 def_bool y if X86_64 355 356config KASAN_SHADOW_OFFSET 357 hex 358 depends on KASAN 359 default 0xdffffc0000000000 360 361config HAVE_INTEL_TXT 362 def_bool y 363 depends on INTEL_IOMMU && ACPI 364 365config X86_32_SMP 366 def_bool y 367 depends on X86_32 && SMP 368 369config X86_64_SMP 370 def_bool y 371 depends on X86_64 && SMP 372 373config ARCH_SUPPORTS_UPROBES 374 def_bool y 375 376config FIX_EARLYCON_MEM 377 def_bool y 378 379config DYNAMIC_PHYSICAL_MASK 380 bool 381 382config PGTABLE_LEVELS 383 int 384 default 5 if X86_5LEVEL 385 default 4 if X86_64 386 default 3 if X86_PAE 387 default 2 388 389config CC_HAS_SANE_STACKPROTECTOR 390 bool 391 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 392 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 393 help 394 We have to make sure stack protector is unconditionally disabled if 395 the compiler produces broken code or if it does not let us control 396 the segment on 32-bit kernels. 397 398menu "Processor type and features" 399 400config SMP 401 bool "Symmetric multi-processing support" 402 help 403 This enables support for systems with more than one CPU. If you have 404 a system with only one CPU, say N. If you have a system with more 405 than one CPU, say Y. 406 407 If you say N here, the kernel will run on uni- and multiprocessor 408 machines, but will use only one CPU of a multiprocessor machine. If 409 you say Y here, the kernel will run on many, but not all, 410 uniprocessor machines. On a uniprocessor machine, the kernel 411 will run faster if you say N here. 412 413 Note that if you say Y here and choose architecture "586" or 414 "Pentium" under "Processor family", the kernel will not work on 486 415 architectures. Similarly, multiprocessor kernels for the "PPro" 416 architecture may not work on all Pentium based boards. 417 418 People using multiprocessor machines who say Y here should also say 419 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 420 Management" code will be disabled if you say Y here. 421 422 See also <file:Documentation/x86/i386/IO-APIC.rst>, 423 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 424 <http://www.tldp.org/docs.html#howto>. 425 426 If you don't know what to do here, say N. 427 428config X86_FEATURE_NAMES 429 bool "Processor feature human-readable names" if EMBEDDED 430 default y 431 help 432 This option compiles in a table of x86 feature bits and corresponding 433 names. This is required to support /proc/cpuinfo and a few kernel 434 messages. You can disable this to save space, at the expense of 435 making those few kernel messages show numeric feature bits instead. 436 437 If in doubt, say Y. 438 439config X86_X2APIC 440 bool "Support x2apic" 441 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 442 help 443 This enables x2apic support on CPUs that have this feature. 444 445 This allows 32-bit apic IDs (so it can support very large systems), 446 and accesses the local apic via MSRs not via mmio. 447 448 If you don't know what to do here, say N. 449 450config X86_MPPARSE 451 bool "Enable MPS table" if ACPI 452 default y 453 depends on X86_LOCAL_APIC 454 help 455 For old smp systems that do not have proper acpi support. Newer systems 456 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 457 458config GOLDFISH 459 def_bool y 460 depends on X86_GOLDFISH 461 462config RETPOLINE 463 bool "Avoid speculative indirect branches in kernel" 464 default y 465 help 466 Compile kernel with the retpoline compiler options to guard against 467 kernel-to-user data leaks by avoiding speculative indirect 468 branches. Requires a compiler with -mindirect-branch=thunk-extern 469 support for full protection. The kernel may run slower. 470 471config CC_HAS_SLS 472 def_bool $(cc-option,-mharden-sls=all) 473 474config SLS 475 bool "Mitigate Straight-Line-Speculation" 476 depends on CC_HAS_SLS && X86_64 477 default n 478 help 479 Compile the kernel with straight-line-speculation options to guard 480 against straight line speculation. The kernel image might be slightly 481 larger. 482 483config X86_CPU_RESCTRL 484 bool "x86 CPU resource control support" 485 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 486 select KERNFS 487 select PROC_CPU_RESCTRL if PROC_FS 488 help 489 Enable x86 CPU resource control support. 490 491 Provide support for the allocation and monitoring of system resources 492 usage by the CPU. 493 494 Intel calls this Intel Resource Director Technology 495 (Intel(R) RDT). More information about RDT can be found in the 496 Intel x86 Architecture Software Developer Manual. 497 498 AMD calls this AMD Platform Quality of Service (AMD QoS). 499 More information about AMD QoS can be found in the AMD64 Technology 500 Platform Quality of Service Extensions manual. 501 502 Say N if unsure. 503 504if X86_32 505config X86_BIGSMP 506 bool "Support for big SMP systems with more than 8 CPUs" 507 depends on SMP 508 help 509 This option is needed for the systems that have more than 8 CPUs. 510 511config X86_EXTENDED_PLATFORM 512 bool "Support for extended (non-PC) x86 platforms" 513 default y 514 help 515 If you disable this option then the kernel will only support 516 standard PC platforms. (which covers the vast majority of 517 systems out there.) 518 519 If you enable this option then you'll be able to select support 520 for the following (non-PC) 32 bit x86 platforms: 521 Goldfish (Android emulator) 522 AMD Elan 523 RDC R-321x SoC 524 SGI 320/540 (Visual Workstation) 525 STA2X11-based (e.g. Northville) 526 Moorestown MID devices 527 528 If you have one of these systems, or if you want to build a 529 generic distribution kernel, say Y here - otherwise say N. 530endif 531 532if X86_64 533config X86_EXTENDED_PLATFORM 534 bool "Support for extended (non-PC) x86 platforms" 535 default y 536 help 537 If you disable this option then the kernel will only support 538 standard PC platforms. (which covers the vast majority of 539 systems out there.) 540 541 If you enable this option then you'll be able to select support 542 for the following (non-PC) 64 bit x86 platforms: 543 Numascale NumaChip 544 ScaleMP vSMP 545 SGI Ultraviolet 546 547 If you have one of these systems, or if you want to build a 548 generic distribution kernel, say Y here - otherwise say N. 549endif 550# This is an alphabetically sorted list of 64 bit extended platforms 551# Please maintain the alphabetic order if and when there are additions 552config X86_NUMACHIP 553 bool "Numascale NumaChip" 554 depends on X86_64 555 depends on X86_EXTENDED_PLATFORM 556 depends on NUMA 557 depends on SMP 558 depends on X86_X2APIC 559 depends on PCI_MMCONFIG 560 help 561 Adds support for Numascale NumaChip large-SMP systems. Needed to 562 enable more than ~168 cores. 563 If you don't have one of these, you should say N here. 564 565config X86_VSMP 566 bool "ScaleMP vSMP" 567 select HYPERVISOR_GUEST 568 select PARAVIRT 569 depends on X86_64 && PCI 570 depends on X86_EXTENDED_PLATFORM 571 depends on SMP 572 help 573 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 574 supposed to run on these EM64T-based machines. Only choose this option 575 if you have one of these machines. 576 577config X86_UV 578 bool "SGI Ultraviolet" 579 depends on X86_64 580 depends on X86_EXTENDED_PLATFORM 581 depends on NUMA 582 depends on EFI 583 depends on KEXEC_CORE 584 depends on X86_X2APIC 585 depends on PCI 586 help 587 This option is needed in order to support SGI Ultraviolet systems. 588 If you don't have one of these, you should say N here. 589 590# Following is an alphabetically sorted list of 32 bit extended platforms 591# Please maintain the alphabetic order if and when there are additions 592 593config X86_GOLDFISH 594 bool "Goldfish (Virtual Platform)" 595 depends on X86_EXTENDED_PLATFORM 596 help 597 Enable support for the Goldfish virtual platform used primarily 598 for Android development. Unless you are building for the Android 599 Goldfish emulator say N here. 600 601config X86_INTEL_CE 602 bool "CE4100 TV platform" 603 depends on PCI 604 depends on PCI_GODIRECT 605 depends on X86_IO_APIC 606 depends on X86_32 607 depends on X86_EXTENDED_PLATFORM 608 select X86_REBOOTFIXUPS 609 select OF 610 select OF_EARLY_FLATTREE 611 help 612 Select for the Intel CE media processor (CE4100) SOC. 613 This option compiles in support for the CE4100 SOC for settop 614 boxes and media devices. 615 616config X86_INTEL_MID 617 bool "Intel MID platform support" 618 depends on X86_EXTENDED_PLATFORM 619 depends on X86_PLATFORM_DEVICES 620 depends on PCI 621 depends on X86_64 || (PCI_GOANY && X86_32) 622 depends on X86_IO_APIC 623 select I2C 624 select DW_APB_TIMER 625 select INTEL_SCU_PCI 626 help 627 Select to build a kernel capable of supporting Intel MID (Mobile 628 Internet Device) platform systems which do not have the PCI legacy 629 interfaces. If you are building for a PC class system say N here. 630 631 Intel MID platforms are based on an Intel processor and chipset which 632 consume less power than most of the x86 derivatives. 633 634config X86_INTEL_QUARK 635 bool "Intel Quark platform support" 636 depends on X86_32 637 depends on X86_EXTENDED_PLATFORM 638 depends on X86_PLATFORM_DEVICES 639 depends on X86_TSC 640 depends on PCI 641 depends on PCI_GOANY 642 depends on X86_IO_APIC 643 select IOSF_MBI 644 select INTEL_IMR 645 select COMMON_CLK 646 help 647 Select to include support for Quark X1000 SoC. 648 Say Y here if you have a Quark based system such as the Arduino 649 compatible Intel Galileo. 650 651config X86_INTEL_LPSS 652 bool "Intel Low Power Subsystem Support" 653 depends on X86 && ACPI && PCI 654 select COMMON_CLK 655 select PINCTRL 656 select IOSF_MBI 657 help 658 Select to build support for Intel Low Power Subsystem such as 659 found on Intel Lynxpoint PCH. Selecting this option enables 660 things like clock tree (common clock framework) and pincontrol 661 which are needed by the LPSS peripheral drivers. 662 663config X86_AMD_PLATFORM_DEVICE 664 bool "AMD ACPI2Platform devices support" 665 depends on ACPI 666 select COMMON_CLK 667 select PINCTRL 668 help 669 Select to interpret AMD specific ACPI device to platform device 670 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 671 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 672 implemented under PINCTRL subsystem. 673 674config IOSF_MBI 675 tristate "Intel SoC IOSF Sideband support for SoC platforms" 676 depends on PCI 677 help 678 This option enables sideband register access support for Intel SoC 679 platforms. On these platforms the IOSF sideband is used in lieu of 680 MSR's for some register accesses, mostly but not limited to thermal 681 and power. Drivers may query the availability of this device to 682 determine if they need the sideband in order to work on these 683 platforms. The sideband is available on the following SoC products. 684 This list is not meant to be exclusive. 685 - BayTrail 686 - Braswell 687 - Quark 688 689 You should say Y if you are running a kernel on one of these SoC's. 690 691config IOSF_MBI_DEBUG 692 bool "Enable IOSF sideband access through debugfs" 693 depends on IOSF_MBI && DEBUG_FS 694 help 695 Select this option to expose the IOSF sideband access registers (MCR, 696 MDR, MCRX) through debugfs to write and read register information from 697 different units on the SoC. This is most useful for obtaining device 698 state information for debug and analysis. As this is a general access 699 mechanism, users of this option would have specific knowledge of the 700 device they want to access. 701 702 If you don't require the option or are in doubt, say N. 703 704config X86_RDC321X 705 bool "RDC R-321x SoC" 706 depends on X86_32 707 depends on X86_EXTENDED_PLATFORM 708 select M486 709 select X86_REBOOTFIXUPS 710 help 711 This option is needed for RDC R-321x system-on-chip, also known 712 as R-8610-(G). 713 If you don't have one of these chips, you should say N here. 714 715config X86_32_NON_STANDARD 716 bool "Support non-standard 32-bit SMP architectures" 717 depends on X86_32 && SMP 718 depends on X86_EXTENDED_PLATFORM 719 help 720 This option compiles in the bigsmp and STA2X11 default 721 subarchitectures. It is intended for a generic binary 722 kernel. If you select them all, kernel will probe it one by 723 one and will fallback to default. 724 725# Alphabetically sorted list of Non standard 32 bit platforms 726 727config X86_SUPPORTS_MEMORY_FAILURE 728 def_bool y 729 # MCE code calls memory_failure(): 730 depends on X86_MCE 731 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 732 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 733 depends on X86_64 || !SPARSEMEM 734 select ARCH_SUPPORTS_MEMORY_FAILURE 735 736config STA2X11 737 bool "STA2X11 Companion Chip Support" 738 depends on X86_32_NON_STANDARD && PCI 739 select SWIOTLB 740 select MFD_STA2X11 741 select GPIOLIB 742 help 743 This adds support for boards based on the STA2X11 IO-Hub, 744 a.k.a. "ConneXt". The chip is used in place of the standard 745 PC chipset, so all "standard" peripherals are missing. If this 746 option is selected the kernel will still be able to boot on 747 standard PC machines. 748 749config X86_32_IRIS 750 tristate "Eurobraille/Iris poweroff module" 751 depends on X86_32 752 help 753 The Iris machines from EuroBraille do not have APM or ACPI support 754 to shut themselves down properly. A special I/O sequence is 755 needed to do so, which is what this module does at 756 kernel shutdown. 757 758 This is only for Iris machines from EuroBraille. 759 760 If unused, say N. 761 762config SCHED_OMIT_FRAME_POINTER 763 def_bool y 764 prompt "Single-depth WCHAN output" 765 depends on X86 766 help 767 Calculate simpler /proc/<PID>/wchan values. If this option 768 is disabled then wchan values will recurse back to the 769 caller function. This provides more accurate wchan values, 770 at the expense of slightly more scheduling overhead. 771 772 If in doubt, say "Y". 773 774menuconfig HYPERVISOR_GUEST 775 bool "Linux guest support" 776 help 777 Say Y here to enable options for running Linux under various hyper- 778 visors. This option enables basic hypervisor detection and platform 779 setup. 780 781 If you say N, all options in this submenu will be skipped and 782 disabled, and Linux guest support won't be built in. 783 784if HYPERVISOR_GUEST 785 786config PARAVIRT 787 bool "Enable paravirtualization code" 788 depends on HAVE_STATIC_CALL 789 help 790 This changes the kernel so it can modify itself when it is run 791 under a hypervisor, potentially improving performance significantly 792 over full virtualization. However, when run without a hypervisor 793 the kernel is theoretically slower and slightly larger. 794 795config PARAVIRT_XXL 796 bool 797 798config PARAVIRT_DEBUG 799 bool "paravirt-ops debugging" 800 depends on PARAVIRT && DEBUG_KERNEL 801 help 802 Enable to debug paravirt_ops internals. Specifically, BUG if 803 a paravirt_op is missing when it is called. 804 805config PARAVIRT_SPINLOCKS 806 bool "Paravirtualization layer for spinlocks" 807 depends on PARAVIRT && SMP 808 help 809 Paravirtualized spinlocks allow a pvops backend to replace the 810 spinlock implementation with something virtualization-friendly 811 (for example, block the virtual CPU rather than spinning). 812 813 It has a minimal impact on native kernels and gives a nice performance 814 benefit on paravirtualized KVM / Xen kernels. 815 816 If you are unsure how to answer this question, answer Y. 817 818config X86_HV_CALLBACK_VECTOR 819 def_bool n 820 821source "arch/x86/xen/Kconfig" 822 823config KVM_GUEST 824 bool "KVM Guest support (including kvmclock)" 825 depends on PARAVIRT 826 select PARAVIRT_CLOCK 827 select ARCH_CPUIDLE_HALTPOLL 828 select X86_HV_CALLBACK_VECTOR 829 default y 830 help 831 This option enables various optimizations for running under the KVM 832 hypervisor. It includes a paravirtualized clock, so that instead 833 of relying on a PIT (or probably other) emulation by the 834 underlying device model, the host provides the guest with 835 timing infrastructure such as time of day, and system time 836 837config ARCH_CPUIDLE_HALTPOLL 838 def_bool n 839 prompt "Disable host haltpoll when loading haltpoll driver" 840 help 841 If virtualized under KVM, disable host haltpoll. 842 843config PVH 844 bool "Support for running PVH guests" 845 help 846 This option enables the PVH entry point for guest virtual machines 847 as specified in the x86/HVM direct boot ABI. 848 849config PARAVIRT_TIME_ACCOUNTING 850 bool "Paravirtual steal time accounting" 851 depends on PARAVIRT 852 help 853 Select this option to enable fine granularity task steal time 854 accounting. Time spent executing other tasks in parallel with 855 the current vCPU is discounted from the vCPU power. To account for 856 that, there can be a small performance impact. 857 858 If in doubt, say N here. 859 860config PARAVIRT_CLOCK 861 bool 862 863config JAILHOUSE_GUEST 864 bool "Jailhouse non-root cell support" 865 depends on X86_64 && PCI 866 select X86_PM_TIMER 867 help 868 This option allows to run Linux as guest in a Jailhouse non-root 869 cell. You can leave this option disabled if you only want to start 870 Jailhouse and run Linux afterwards in the root cell. 871 872config ACRN_GUEST 873 bool "ACRN Guest support" 874 depends on X86_64 875 select X86_HV_CALLBACK_VECTOR 876 help 877 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 878 a flexible, lightweight reference open-source hypervisor, built with 879 real-time and safety-criticality in mind. It is built for embedded 880 IOT with small footprint and real-time features. More details can be 881 found in https://projectacrn.org/. 882 883endif #HYPERVISOR_GUEST 884 885source "arch/x86/Kconfig.cpu" 886 887config HPET_TIMER 888 def_bool X86_64 889 prompt "HPET Timer Support" if X86_32 890 help 891 Use the IA-PC HPET (High Precision Event Timer) to manage 892 time in preference to the PIT and RTC, if a HPET is 893 present. 894 HPET is the next generation timer replacing legacy 8254s. 895 The HPET provides a stable time base on SMP 896 systems, unlike the TSC, but it is more expensive to access, 897 as it is off-chip. The interface used is documented 898 in the HPET spec, revision 1. 899 900 You can safely choose Y here. However, HPET will only be 901 activated if the platform and the BIOS support this feature. 902 Otherwise the 8254 will be used for timing services. 903 904 Choose N to continue using the legacy 8254 timer. 905 906config HPET_EMULATE_RTC 907 def_bool y 908 depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 909 910# Mark as expert because too many people got it wrong. 911# The code disables itself when not needed. 912config DMI 913 default y 914 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 915 bool "Enable DMI scanning" if EXPERT 916 help 917 Enabled scanning of DMI to identify machine quirks. Say Y 918 here unless you have verified that your setup is not 919 affected by entries in the DMI blacklist. Required by PNP 920 BIOS code. 921 922config GART_IOMMU 923 bool "Old AMD GART IOMMU support" 924 select DMA_OPS 925 select IOMMU_HELPER 926 select SWIOTLB 927 depends on X86_64 && PCI && AMD_NB 928 help 929 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 930 GART based hardware IOMMUs. 931 932 The GART supports full DMA access for devices with 32-bit access 933 limitations, on systems with more than 3 GB. This is usually needed 934 for USB, sound, many IDE/SATA chipsets and some other devices. 935 936 Newer systems typically have a modern AMD IOMMU, supported via 937 the CONFIG_AMD_IOMMU=y config option. 938 939 In normal configurations this driver is only active when needed: 940 there's more than 3 GB of memory and the system contains a 941 32-bit limited device. 942 943 If unsure, say Y. 944 945config MAXSMP 946 bool "Enable Maximum number of SMP Processors and NUMA Nodes" 947 depends on X86_64 && SMP && DEBUG_KERNEL 948 select CPUMASK_OFFSTACK 949 help 950 Enable maximum number of CPUS and NUMA Nodes for this architecture. 951 If unsure, say N. 952 953# 954# The maximum number of CPUs supported: 955# 956# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 957# and which can be configured interactively in the 958# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 959# 960# The ranges are different on 32-bit and 64-bit kernels, depending on 961# hardware capabilities and scalability features of the kernel. 962# 963# ( If MAXSMP is enabled we just use the highest possible value and disable 964# interactive configuration. ) 965# 966 967config NR_CPUS_RANGE_BEGIN 968 int 969 default NR_CPUS_RANGE_END if MAXSMP 970 default 1 if !SMP 971 default 2 972 973config NR_CPUS_RANGE_END 974 int 975 depends on X86_32 976 default 64 if SMP && X86_BIGSMP 977 default 8 if SMP && !X86_BIGSMP 978 default 1 if !SMP 979 980config NR_CPUS_RANGE_END 981 int 982 depends on X86_64 983 default 8192 if SMP && CPUMASK_OFFSTACK 984 default 512 if SMP && !CPUMASK_OFFSTACK 985 default 1 if !SMP 986 987config NR_CPUS_DEFAULT 988 int 989 depends on X86_32 990 default 32 if X86_BIGSMP 991 default 8 if SMP 992 default 1 if !SMP 993 994config NR_CPUS_DEFAULT 995 int 996 depends on X86_64 997 default 8192 if MAXSMP 998 default 64 if SMP 999 default 1 if !SMP 1000 1001config NR_CPUS 1002 int "Maximum number of CPUs" if SMP && !MAXSMP 1003 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1004 default NR_CPUS_DEFAULT 1005 help 1006 This allows you to specify the maximum number of CPUs which this 1007 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1008 supported value is 8192, otherwise the maximum value is 512. The 1009 minimum value which makes sense is 2. 1010 1011 This is purely to save memory: each supported CPU adds about 8KB 1012 to the kernel image. 1013 1014config SCHED_CLUSTER 1015 bool "Cluster scheduler support" 1016 depends on SMP 1017 default y 1018 help 1019 Cluster scheduler support improves the CPU scheduler's decision 1020 making when dealing with machines that have clusters of CPUs. 1021 Cluster usually means a couple of CPUs which are placed closely 1022 by sharing mid-level caches, last-level cache tags or internal 1023 busses. 1024 1025config SCHED_SMT 1026 def_bool y if SMP 1027 1028config SCHED_MC 1029 def_bool y 1030 prompt "Multi-core scheduler support" 1031 depends on SMP 1032 help 1033 Multi-core scheduler support improves the CPU scheduler's decision 1034 making when dealing with multi-core CPU chips at a cost of slightly 1035 increased overhead in some places. If unsure say N here. 1036 1037config SCHED_MC_PRIO 1038 bool "CPU core priorities scheduler support" 1039 depends on SCHED_MC && CPU_SUP_INTEL 1040 select X86_INTEL_PSTATE 1041 select CPU_FREQ 1042 default y 1043 help 1044 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1045 core ordering determined at manufacturing time, which allows 1046 certain cores to reach higher turbo frequencies (when running 1047 single threaded workloads) than others. 1048 1049 Enabling this kernel feature teaches the scheduler about 1050 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1051 scheduler's CPU selection logic accordingly, so that higher 1052 overall system performance can be achieved. 1053 1054 This feature will have no effect on CPUs without this feature. 1055 1056 If unsure say Y here. 1057 1058config UP_LATE_INIT 1059 def_bool y 1060 depends on !SMP && X86_LOCAL_APIC 1061 1062config X86_UP_APIC 1063 bool "Local APIC support on uniprocessors" if !PCI_MSI 1064 default PCI_MSI 1065 depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1066 help 1067 A local APIC (Advanced Programmable Interrupt Controller) is an 1068 integrated interrupt controller in the CPU. If you have a single-CPU 1069 system which has a processor with a local APIC, you can say Y here to 1070 enable and use it. If you say Y here even though your machine doesn't 1071 have a local APIC, then the kernel will still run with no slowdown at 1072 all. The local APIC supports CPU-generated self-interrupts (timer, 1073 performance counters), and the NMI watchdog which detects hard 1074 lockups. 1075 1076config X86_UP_IOAPIC 1077 bool "IO-APIC support on uniprocessors" 1078 depends on X86_UP_APIC 1079 help 1080 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1081 SMP-capable replacement for PC-style interrupt controllers. Most 1082 SMP systems and many recent uniprocessor systems have one. 1083 1084 If you have a single-CPU system with an IO-APIC, you can say Y here 1085 to use it. If you say Y here even though your machine doesn't have 1086 an IO-APIC, then the kernel will still run with no slowdown at all. 1087 1088config X86_LOCAL_APIC 1089 def_bool y 1090 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1091 select IRQ_DOMAIN_HIERARCHY 1092 select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1093 1094config X86_IO_APIC 1095 def_bool y 1096 depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1097 1098config X86_REROUTE_FOR_BROKEN_BOOT_IRQS 1099 bool "Reroute for broken boot IRQs" 1100 depends on X86_IO_APIC 1101 help 1102 This option enables a workaround that fixes a source of 1103 spurious interrupts. This is recommended when threaded 1104 interrupt handling is used on systems where the generation of 1105 superfluous "boot interrupts" cannot be disabled. 1106 1107 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 1108 entry in the chipset's IO-APIC is masked (as, e.g. the RT 1109 kernel does during interrupt handling). On chipsets where this 1110 boot IRQ generation cannot be disabled, this workaround keeps 1111 the original IRQ line masked so that only the equivalent "boot 1112 IRQ" is delivered to the CPUs. The workaround also tells the 1113 kernel to set up the IRQ handler on the boot IRQ line. In this 1114 way only one interrupt is delivered to the kernel. Otherwise 1115 the spurious second interrupt may cause the kernel to bring 1116 down (vital) interrupt lines. 1117 1118 Only affects "broken" chipsets. Interrupt sharing may be 1119 increased on these systems. 1120 1121config X86_MCE 1122 bool "Machine Check / overheating reporting" 1123 select GENERIC_ALLOCATOR 1124 default y 1125 help 1126 Machine Check support allows the processor to notify the 1127 kernel if it detects a problem (e.g. overheating, data corruption). 1128 The action the kernel takes depends on the severity of the problem, 1129 ranging from warning messages to halting the machine. 1130 1131config X86_MCELOG_LEGACY 1132 bool "Support for deprecated /dev/mcelog character device" 1133 depends on X86_MCE 1134 help 1135 Enable support for /dev/mcelog which is needed by the old mcelog 1136 userspace logging daemon. Consider switching to the new generation 1137 rasdaemon solution. 1138 1139config X86_MCE_INTEL 1140 def_bool y 1141 prompt "Intel MCE features" 1142 depends on X86_MCE && X86_LOCAL_APIC 1143 help 1144 Additional support for intel specific MCE features such as 1145 the thermal monitor. 1146 1147config X86_MCE_AMD 1148 def_bool y 1149 prompt "AMD MCE features" 1150 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1151 help 1152 Additional support for AMD specific MCE features such as 1153 the DRAM Error Threshold. 1154 1155config X86_ANCIENT_MCE 1156 bool "Support for old Pentium 5 / WinChip machine checks" 1157 depends on X86_32 && X86_MCE 1158 help 1159 Include support for machine check handling on old Pentium 5 or WinChip 1160 systems. These typically need to be enabled explicitly on the command 1161 line. 1162 1163config X86_MCE_THRESHOLD 1164 depends on X86_MCE_AMD || X86_MCE_INTEL 1165 def_bool y 1166 1167config X86_MCE_INJECT 1168 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1169 tristate "Machine check injector support" 1170 help 1171 Provide support for injecting machine checks for testing purposes. 1172 If you don't know what a machine check is and you don't do kernel 1173 QA it is safe to say n. 1174 1175source "arch/x86/events/Kconfig" 1176 1177config X86_LEGACY_VM86 1178 bool "Legacy VM86 support" 1179 depends on X86_32 1180 help 1181 This option allows user programs to put the CPU into V8086 1182 mode, which is an 80286-era approximation of 16-bit real mode. 1183 1184 Some very old versions of X and/or vbetool require this option 1185 for user mode setting. Similarly, DOSEMU will use it if 1186 available to accelerate real mode DOS programs. However, any 1187 recent version of DOSEMU, X, or vbetool should be fully 1188 functional even without kernel VM86 support, as they will all 1189 fall back to software emulation. Nevertheless, if you are using 1190 a 16-bit DOS program where 16-bit performance matters, vm86 1191 mode might be faster than emulation and you might want to 1192 enable this option. 1193 1194 Note that any app that works on a 64-bit kernel is unlikely to 1195 need this option, as 64-bit kernels don't, and can't, support 1196 V8086 mode. This option is also unrelated to 16-bit protected 1197 mode and is not needed to run most 16-bit programs under Wine. 1198 1199 Enabling this option increases the complexity of the kernel 1200 and slows down exception handling a tiny bit. 1201 1202 If unsure, say N here. 1203 1204config VM86 1205 bool 1206 default X86_LEGACY_VM86 1207 1208config X86_16BIT 1209 bool "Enable support for 16-bit segments" if EXPERT 1210 default y 1211 depends on MODIFY_LDT_SYSCALL 1212 help 1213 This option is required by programs like Wine to run 16-bit 1214 protected mode legacy code on x86 processors. Disabling 1215 this option saves about 300 bytes on i386, or around 6K text 1216 plus 16K runtime memory on x86-64, 1217 1218config X86_ESPFIX32 1219 def_bool y 1220 depends on X86_16BIT && X86_32 1221 1222config X86_ESPFIX64 1223 def_bool y 1224 depends on X86_16BIT && X86_64 1225 1226config X86_VSYSCALL_EMULATION 1227 bool "Enable vsyscall emulation" if EXPERT 1228 default y 1229 depends on X86_64 1230 help 1231 This enables emulation of the legacy vsyscall page. Disabling 1232 it is roughly equivalent to booting with vsyscall=none, except 1233 that it will also disable the helpful warning if a program 1234 tries to use a vsyscall. With this option set to N, offending 1235 programs will just segfault, citing addresses of the form 1236 0xffffffffff600?00. 1237 1238 This option is required by many programs built before 2013, and 1239 care should be used even with newer programs if set to N. 1240 1241 Disabling this option saves about 7K of kernel size and 1242 possibly 4K of additional runtime pagetable memory. 1243 1244config X86_IOPL_IOPERM 1245 bool "IOPERM and IOPL Emulation" 1246 default y 1247 help 1248 This enables the ioperm() and iopl() syscalls which are necessary 1249 for legacy applications. 1250 1251 Legacy IOPL support is an overbroad mechanism which allows user 1252 space aside of accessing all 65536 I/O ports also to disable 1253 interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1254 capabilities and permission from potentially active security 1255 modules. 1256 1257 The emulation restricts the functionality of the syscall to 1258 only allowing the full range I/O port access, but prevents the 1259 ability to disable interrupts from user space which would be 1260 granted if the hardware IOPL mechanism would be used. 1261 1262config TOSHIBA 1263 tristate "Toshiba Laptop support" 1264 depends on X86_32 1265 help 1266 This adds a driver to safely access the System Management Mode of 1267 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1268 not work on models with a Phoenix BIOS. The System Management Mode 1269 is used to set the BIOS and power saving options on Toshiba portables. 1270 1271 For information on utilities to make use of this driver see the 1272 Toshiba Linux utilities web site at: 1273 <http://www.buzzard.org.uk/toshiba/>. 1274 1275 Say Y if you intend to run this kernel on a Toshiba portable. 1276 Say N otherwise. 1277 1278config I8K 1279 tristate "Dell i8k legacy laptop support" 1280 depends on HWMON 1281 depends on PROC_FS 1282 select SENSORS_DELL_SMM 1283 help 1284 This option enables legacy /proc/i8k userspace interface in hwmon 1285 dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1286 temperature and allows controlling fan speeds of Dell laptops via 1287 System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1288 it reports also power and hotkey status. For fan speed control is 1289 needed userspace package i8kutils. 1290 1291 Say Y if you intend to run this kernel on old Dell laptops or want to 1292 use userspace package i8kutils. 1293 Say N otherwise. 1294 1295config X86_REBOOTFIXUPS 1296 bool "Enable X86 board specific fixups for reboot" 1297 depends on X86_32 1298 help 1299 This enables chipset and/or board specific fixups to be done 1300 in order to get reboot to work correctly. This is only needed on 1301 some combinations of hardware and BIOS. The symptom, for which 1302 this config is intended, is when reboot ends with a stalled/hung 1303 system. 1304 1305 Currently, the only fixup is for the Geode machines using 1306 CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1307 1308 Say Y if you want to enable the fixup. Currently, it's safe to 1309 enable this option even if you don't need it. 1310 Say N otherwise. 1311 1312config MICROCODE 1313 bool "CPU microcode loading support" 1314 default y 1315 depends on CPU_SUP_AMD || CPU_SUP_INTEL 1316 help 1317 If you say Y here, you will be able to update the microcode on 1318 Intel and AMD processors. The Intel support is for the IA32 family, 1319 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 1320 AMD support is for families 0x10 and later. You will obviously need 1321 the actual microcode binary data itself which is not shipped with 1322 the Linux kernel. 1323 1324 The preferred method to load microcode from a detached initrd is described 1325 in Documentation/x86/microcode.rst. For that you need to enable 1326 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 1327 initrd for microcode blobs. 1328 1329 In addition, you can build the microcode into the kernel. For that you 1330 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1331 config option. 1332 1333config MICROCODE_INTEL 1334 bool "Intel microcode loading support" 1335 depends on MICROCODE 1336 default MICROCODE 1337 help 1338 This options enables microcode patch loading support for Intel 1339 processors. 1340 1341 For the current Intel microcode data package go to 1342 <https://downloadcenter.intel.com> and search for 1343 'Linux Processor Microcode Data File'. 1344 1345config MICROCODE_AMD 1346 bool "AMD microcode loading support" 1347 depends on MICROCODE 1348 help 1349 If you select this option, microcode patch loading support for AMD 1350 processors will be enabled. 1351 1352config MICROCODE_OLD_INTERFACE 1353 bool "Ancient loading interface (DEPRECATED)" 1354 default n 1355 depends on MICROCODE 1356 help 1357 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1358 which was used by userspace tools like iucode_tool and microcode.ctl. 1359 It is inadequate because it runs too late to be able to properly 1360 load microcode on a machine and it needs special tools. Instead, you 1361 should've switched to the early loading method with the initrd or 1362 builtin microcode by now: Documentation/x86/microcode.rst 1363 1364config X86_MSR 1365 tristate "/dev/cpu/*/msr - Model-specific register support" 1366 help 1367 This device gives privileged processes access to the x86 1368 Model-Specific Registers (MSRs). It is a character device with 1369 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1370 MSR accesses are directed to a specific CPU on multi-processor 1371 systems. 1372 1373config X86_CPUID 1374 tristate "/dev/cpu/*/cpuid - CPU information support" 1375 help 1376 This device gives processes access to the x86 CPUID instruction to 1377 be executed on a specific processor. It is a character device 1378 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1379 /dev/cpu/31/cpuid. 1380 1381choice 1382 prompt "High Memory Support" 1383 default HIGHMEM4G 1384 depends on X86_32 1385 1386config NOHIGHMEM 1387 bool "off" 1388 help 1389 Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1390 However, the address space of 32-bit x86 processors is only 4 1391 Gigabytes large. That means that, if you have a large amount of 1392 physical memory, not all of it can be "permanently mapped" by the 1393 kernel. The physical memory that's not permanently mapped is called 1394 "high memory". 1395 1396 If you are compiling a kernel which will never run on a machine with 1397 more than 1 Gigabyte total physical RAM, answer "off" here (default 1398 choice and suitable for most users). This will result in a "3GB/1GB" 1399 split: 3GB are mapped so that each process sees a 3GB virtual memory 1400 space and the remaining part of the 4GB virtual memory space is used 1401 by the kernel to permanently map as much physical memory as 1402 possible. 1403 1404 If the machine has between 1 and 4 Gigabytes physical RAM, then 1405 answer "4GB" here. 1406 1407 If more than 4 Gigabytes is used then answer "64GB" here. This 1408 selection turns Intel PAE (Physical Address Extension) mode on. 1409 PAE implements 3-level paging on IA32 processors. PAE is fully 1410 supported by Linux, PAE mode is implemented on all recent Intel 1411 processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1412 then the kernel will not boot on CPUs that don't support PAE! 1413 1414 The actual amount of total physical memory will either be 1415 auto detected or can be forced by using a kernel command line option 1416 such as "mem=256M". (Try "man bootparam" or see the documentation of 1417 your boot loader (lilo or loadlin) about how to pass options to the 1418 kernel at boot time.) 1419 1420 If unsure, say "off". 1421 1422config HIGHMEM4G 1423 bool "4GB" 1424 help 1425 Select this if you have a 32-bit processor and between 1 and 4 1426 gigabytes of physical RAM. 1427 1428config HIGHMEM64G 1429 bool "64GB" 1430 depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6 1431 select X86_PAE 1432 help 1433 Select this if you have a 32-bit processor and more than 4 1434 gigabytes of physical RAM. 1435 1436endchoice 1437 1438choice 1439 prompt "Memory split" if EXPERT 1440 default VMSPLIT_3G 1441 depends on X86_32 1442 help 1443 Select the desired split between kernel and user memory. 1444 1445 If the address range available to the kernel is less than the 1446 physical memory installed, the remaining memory will be available 1447 as "high memory". Accessing high memory is a little more costly 1448 than low memory, as it needs to be mapped into the kernel first. 1449 Note that increasing the kernel address space limits the range 1450 available to user programs, making the address space there 1451 tighter. Selecting anything other than the default 3G/1G split 1452 will also likely make your kernel incompatible with binary-only 1453 kernel modules. 1454 1455 If you are not absolutely sure what you are doing, leave this 1456 option alone! 1457 1458 config VMSPLIT_3G 1459 bool "3G/1G user/kernel split" 1460 config VMSPLIT_3G_OPT 1461 depends on !X86_PAE 1462 bool "3G/1G user/kernel split (for full 1G low memory)" 1463 config VMSPLIT_2G 1464 bool "2G/2G user/kernel split" 1465 config VMSPLIT_2G_OPT 1466 depends on !X86_PAE 1467 bool "2G/2G user/kernel split (for full 2G low memory)" 1468 config VMSPLIT_1G 1469 bool "1G/3G user/kernel split" 1470endchoice 1471 1472config PAGE_OFFSET 1473 hex 1474 default 0xB0000000 if VMSPLIT_3G_OPT 1475 default 0x80000000 if VMSPLIT_2G 1476 default 0x78000000 if VMSPLIT_2G_OPT 1477 default 0x40000000 if VMSPLIT_1G 1478 default 0xC0000000 1479 depends on X86_32 1480 1481config HIGHMEM 1482 def_bool y 1483 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1484 1485config X86_PAE 1486 bool "PAE (Physical Address Extension) Support" 1487 depends on X86_32 && !HIGHMEM4G 1488 select PHYS_ADDR_T_64BIT 1489 select SWIOTLB 1490 help 1491 PAE is required for NX support, and furthermore enables 1492 larger swapspace support for non-overcommit purposes. It 1493 has the cost of more pagetable lookup overhead, and also 1494 consumes more pagetable space per process. 1495 1496config X86_5LEVEL 1497 bool "Enable 5-level page tables support" 1498 default y 1499 select DYNAMIC_MEMORY_LAYOUT 1500 select SPARSEMEM_VMEMMAP 1501 depends on X86_64 1502 help 1503 5-level paging enables access to larger address space: 1504 upto 128 PiB of virtual address space and 4 PiB of 1505 physical address space. 1506 1507 It will be supported by future Intel CPUs. 1508 1509 A kernel with the option enabled can be booted on machines that 1510 support 4- or 5-level paging. 1511 1512 See Documentation/x86/x86_64/5level-paging.rst for more 1513 information. 1514 1515 Say N if unsure. 1516 1517config X86_DIRECT_GBPAGES 1518 def_bool y 1519 depends on X86_64 1520 help 1521 Certain kernel features effectively disable kernel 1522 linear 1 GB mappings (even if the CPU otherwise 1523 supports them), so don't confuse the user by printing 1524 that we have them enabled. 1525 1526config X86_CPA_STATISTICS 1527 bool "Enable statistic for Change Page Attribute" 1528 depends on DEBUG_FS 1529 help 1530 Expose statistics about the Change Page Attribute mechanism, which 1531 helps to determine the effectiveness of preserving large and huge 1532 page mappings when mapping protections are changed. 1533 1534config X86_MEM_ENCRYPT 1535 select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1536 select DYNAMIC_PHYSICAL_MASK 1537 select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS 1538 def_bool n 1539 1540config AMD_MEM_ENCRYPT 1541 bool "AMD Secure Memory Encryption (SME) support" 1542 depends on X86_64 && CPU_SUP_AMD 1543 select DMA_COHERENT_POOL 1544 select ARCH_USE_MEMREMAP_PROT 1545 select INSTRUCTION_DECODER 1546 select ARCH_HAS_CC_PLATFORM 1547 select X86_MEM_ENCRYPT 1548 help 1549 Say yes to enable support for the encryption of system memory. 1550 This requires an AMD processor that supports Secure Memory 1551 Encryption (SME). 1552 1553config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 1554 bool "Activate AMD Secure Memory Encryption (SME) by default" 1555 depends on AMD_MEM_ENCRYPT 1556 help 1557 Say yes to have system memory encrypted by default if running on 1558 an AMD processor that supports Secure Memory Encryption (SME). 1559 1560 If set to Y, then the encryption of system memory can be 1561 deactivated with the mem_encrypt=off command line option. 1562 1563 If set to N, then the encryption of system memory can be 1564 activated with the mem_encrypt=on command line option. 1565 1566# Common NUMA Features 1567config NUMA 1568 bool "NUMA Memory Allocation and Scheduler Support" 1569 depends on SMP 1570 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1571 default y if X86_BIGSMP 1572 select USE_PERCPU_NUMA_NODE_ID 1573 help 1574 Enable NUMA (Non-Uniform Memory Access) support. 1575 1576 The kernel will try to allocate memory used by a CPU on the 1577 local memory controller of the CPU and add some more 1578 NUMA awareness to the kernel. 1579 1580 For 64-bit this is recommended if the system is Intel Core i7 1581 (or later), AMD Opteron, or EM64T NUMA. 1582 1583 For 32-bit this is only needed if you boot a 32-bit 1584 kernel on a 64-bit NUMA platform. 1585 1586 Otherwise, you should say N. 1587 1588config AMD_NUMA 1589 def_bool y 1590 prompt "Old style AMD Opteron NUMA detection" 1591 depends on X86_64 && NUMA && PCI 1592 help 1593 Enable AMD NUMA node topology detection. You should say Y here if 1594 you have a multi processor AMD system. This uses an old method to 1595 read the NUMA configuration directly from the builtin Northbridge 1596 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1597 which also takes priority if both are compiled in. 1598 1599config X86_64_ACPI_NUMA 1600 def_bool y 1601 prompt "ACPI NUMA detection" 1602 depends on X86_64 && NUMA && ACPI && PCI 1603 select ACPI_NUMA 1604 help 1605 Enable ACPI SRAT based node topology detection. 1606 1607config NUMA_EMU 1608 bool "NUMA emulation" 1609 depends on NUMA 1610 help 1611 Enable NUMA emulation. A flat machine will be split 1612 into virtual nodes when booted with "numa=fake=N", where N is the 1613 number of nodes. This is only useful for debugging. 1614 1615config NODES_SHIFT 1616 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 1617 range 1 10 1618 default "10" if MAXSMP 1619 default "6" if X86_64 1620 default "3" 1621 depends on NUMA 1622 help 1623 Specify the maximum number of NUMA Nodes available on the target 1624 system. Increases memory reserved to accommodate various tables. 1625 1626config ARCH_FLATMEM_ENABLE 1627 def_bool y 1628 depends on X86_32 && !NUMA 1629 1630config ARCH_SPARSEMEM_ENABLE 1631 def_bool y 1632 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1633 select SPARSEMEM_STATIC if X86_32 1634 select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1635 1636config ARCH_SPARSEMEM_DEFAULT 1637 def_bool X86_64 || (NUMA && X86_32) 1638 1639config ARCH_SELECT_MEMORY_MODEL 1640 def_bool y 1641 depends on ARCH_SPARSEMEM_ENABLE 1642 1643config ARCH_MEMORY_PROBE 1644 bool "Enable sysfs memory/probe interface" 1645 depends on MEMORY_HOTPLUG 1646 help 1647 This option enables a sysfs memory/probe interface for testing. 1648 See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1649 If you are unsure how to answer this question, answer N. 1650 1651config ARCH_PROC_KCORE_TEXT 1652 def_bool y 1653 depends on X86_64 && PROC_KCORE 1654 1655config ILLEGAL_POINTER_VALUE 1656 hex 1657 default 0 if X86_32 1658 default 0xdead000000000000 if X86_64 1659 1660config X86_PMEM_LEGACY_DEVICE 1661 bool 1662 1663config X86_PMEM_LEGACY 1664 tristate "Support non-standard NVDIMMs and ADR protected memory" 1665 depends on PHYS_ADDR_T_64BIT 1666 depends on BLK_DEV 1667 select X86_PMEM_LEGACY_DEVICE 1668 select NUMA_KEEP_MEMINFO if NUMA 1669 select LIBNVDIMM 1670 help 1671 Treat memory marked using the non-standard e820 type of 12 as used 1672 by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1673 The kernel will offer these regions to the 'pmem' driver so 1674 they can be used for persistent storage. 1675 1676 Say Y if unsure. 1677 1678config HIGHPTE 1679 bool "Allocate 3rd-level pagetables from highmem" 1680 depends on HIGHMEM 1681 help 1682 The VM uses one page table entry for each page of physical memory. 1683 For systems with a lot of RAM, this can be wasteful of precious 1684 low memory. Setting this option will put user-space page table 1685 entries in high memory. 1686 1687config X86_CHECK_BIOS_CORRUPTION 1688 bool "Check for low memory corruption" 1689 help 1690 Periodically check for memory corruption in low memory, which 1691 is suspected to be caused by BIOS. Even when enabled in the 1692 configuration, it is disabled at runtime. Enable it by 1693 setting "memory_corruption_check=1" on the kernel command 1694 line. By default it scans the low 64k of memory every 60 1695 seconds; see the memory_corruption_check_size and 1696 memory_corruption_check_period parameters in 1697 Documentation/admin-guide/kernel-parameters.rst to adjust this. 1698 1699 When enabled with the default parameters, this option has 1700 almost no overhead, as it reserves a relatively small amount 1701 of memory and scans it infrequently. It both detects corruption 1702 and prevents it from affecting the running system. 1703 1704 It is, however, intended as a diagnostic tool; if repeatable 1705 BIOS-originated corruption always affects the same memory, 1706 you can use memmap= to prevent the kernel from using that 1707 memory. 1708 1709config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1710 bool "Set the default setting of memory_corruption_check" 1711 depends on X86_CHECK_BIOS_CORRUPTION 1712 default y 1713 help 1714 Set whether the default state of memory_corruption_check is 1715 on or off. 1716 1717config MATH_EMULATION 1718 bool 1719 depends on MODIFY_LDT_SYSCALL 1720 prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1721 help 1722 Linux can emulate a math coprocessor (used for floating point 1723 operations) if you don't have one. 486DX and Pentium processors have 1724 a math coprocessor built in, 486SX and 386 do not, unless you added 1725 a 487DX or 387, respectively. (The messages during boot time can 1726 give you some hints here ["man dmesg"].) Everyone needs either a 1727 coprocessor or this emulation. 1728 1729 If you don't have a math coprocessor, you need to say Y here; if you 1730 say Y here even though you have a coprocessor, the coprocessor will 1731 be used nevertheless. (This behavior can be changed with the kernel 1732 command line option "no387", which comes handy if your coprocessor 1733 is broken. Try "man bootparam" or see the documentation of your boot 1734 loader (lilo or loadlin) about how to pass options to the kernel at 1735 boot time.) This means that it is a good idea to say Y here if you 1736 intend to use this kernel on different machines. 1737 1738 More information about the internals of the Linux math coprocessor 1739 emulation can be found in <file:arch/x86/math-emu/README>. 1740 1741 If you are not sure, say Y; apart from resulting in a 66 KB bigger 1742 kernel, it won't hurt. 1743 1744config MTRR 1745 def_bool y 1746 prompt "MTRR (Memory Type Range Register) support" if EXPERT 1747 help 1748 On Intel P6 family processors (Pentium Pro, Pentium II and later) 1749 the Memory Type Range Registers (MTRRs) may be used to control 1750 processor access to memory ranges. This is most useful if you have 1751 a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1752 allows bus write transfers to be combined into a larger transfer 1753 before bursting over the PCI/AGP bus. This can increase performance 1754 of image write operations 2.5 times or more. Saying Y here creates a 1755 /proc/mtrr file which may be used to manipulate your processor's 1756 MTRRs. Typically the X server should use this. 1757 1758 This code has a reasonably generic interface so that similar 1759 control registers on other processors can be easily supported 1760 as well: 1761 1762 The Cyrix 6x86, 6x86MX and M II processors have Address Range 1763 Registers (ARRs) which provide a similar functionality to MTRRs. For 1764 these, the ARRs are used to emulate the MTRRs. 1765 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1766 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1767 write-combining. All of these processors are supported by this code 1768 and it makes sense to say Y here if you have one of them. 1769 1770 Saying Y here also fixes a problem with buggy SMP BIOSes which only 1771 set the MTRRs for the boot CPU and not for the secondary CPUs. This 1772 can lead to all sorts of problems, so it's good to say Y here. 1773 1774 You can safely say Y even if your machine doesn't have MTRRs, you'll 1775 just add about 9 KB to your kernel. 1776 1777 See <file:Documentation/x86/mtrr.rst> for more information. 1778 1779config MTRR_SANITIZER 1780 def_bool y 1781 prompt "MTRR cleanup support" 1782 depends on MTRR 1783 help 1784 Convert MTRR layout from continuous to discrete, so X drivers can 1785 add writeback entries. 1786 1787 Can be disabled with disable_mtrr_cleanup on the kernel command line. 1788 The largest mtrr entry size for a continuous block can be set with 1789 mtrr_chunk_size. 1790 1791 If unsure, say Y. 1792 1793config MTRR_SANITIZER_ENABLE_DEFAULT 1794 int "MTRR cleanup enable value (0-1)" 1795 range 0 1 1796 default "0" 1797 depends on MTRR_SANITIZER 1798 help 1799 Enable mtrr cleanup default value 1800 1801config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 1802 int "MTRR cleanup spare reg num (0-7)" 1803 range 0 7 1804 default "1" 1805 depends on MTRR_SANITIZER 1806 help 1807 mtrr cleanup spare entries default, it can be changed via 1808 mtrr_spare_reg_nr=N on the kernel command line. 1809 1810config X86_PAT 1811 def_bool y 1812 prompt "x86 PAT support" if EXPERT 1813 depends on MTRR 1814 help 1815 Use PAT attributes to setup page level cache control. 1816 1817 PATs are the modern equivalents of MTRRs and are much more 1818 flexible than MTRRs. 1819 1820 Say N here if you see bootup problems (boot crash, boot hang, 1821 spontaneous reboots) or a non-working video driver. 1822 1823 If unsure, say Y. 1824 1825config ARCH_USES_PG_UNCACHED 1826 def_bool y 1827 depends on X86_PAT 1828 1829config ARCH_RANDOM 1830 def_bool y 1831 prompt "x86 architectural random number generator" if EXPERT 1832 help 1833 Enable the x86 architectural RDRAND instruction 1834 (Intel Bull Mountain technology) to generate random numbers. 1835 If supported, this is a high bandwidth, cryptographically 1836 secure hardware random number generator. 1837 1838config X86_SMAP 1839 def_bool y 1840 prompt "Supervisor Mode Access Prevention" if EXPERT 1841 help 1842 Supervisor Mode Access Prevention (SMAP) is a security 1843 feature in newer Intel processors. There is a small 1844 performance cost if this enabled and turned on; there is 1845 also a small increase in the kernel size if this is enabled. 1846 1847 If unsure, say Y. 1848 1849config X86_UMIP 1850 def_bool y 1851 prompt "User Mode Instruction Prevention" if EXPERT 1852 help 1853 User Mode Instruction Prevention (UMIP) is a security feature in 1854 some x86 processors. If enabled, a general protection fault is 1855 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1856 executed in user mode. These instructions unnecessarily expose 1857 information about the hardware state. 1858 1859 The vast majority of applications do not use these instructions. 1860 For the very few that do, software emulation is provided in 1861 specific cases in protected and virtual-8086 modes. Emulated 1862 results are dummy. 1863 1864config X86_INTEL_MEMORY_PROTECTION_KEYS 1865 prompt "Memory Protection Keys" 1866 def_bool y 1867 # Note: only available in 64-bit mode 1868 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 1869 select ARCH_USES_HIGH_VMA_FLAGS 1870 select ARCH_HAS_PKEYS 1871 help 1872 Memory Protection Keys provides a mechanism for enforcing 1873 page-based protections, but without requiring modification of the 1874 page tables when an application changes protection domains. 1875 1876 For details, see Documentation/core-api/protection-keys.rst 1877 1878 If unsure, say y. 1879 1880choice 1881 prompt "TSX enable mode" 1882 depends on CPU_SUP_INTEL 1883 default X86_INTEL_TSX_MODE_OFF 1884 help 1885 Intel's TSX (Transactional Synchronization Extensions) feature 1886 allows to optimize locking protocols through lock elision which 1887 can lead to a noticeable performance boost. 1888 1889 On the other hand it has been shown that TSX can be exploited 1890 to form side channel attacks (e.g. TAA) and chances are there 1891 will be more of those attacks discovered in the future. 1892 1893 Therefore TSX is not enabled by default (aka tsx=off). An admin 1894 might override this decision by tsx=on the command line parameter. 1895 Even with TSX enabled, the kernel will attempt to enable the best 1896 possible TAA mitigation setting depending on the microcode available 1897 for the particular machine. 1898 1899 This option allows to set the default tsx mode between tsx=on, =off 1900 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1901 details. 1902 1903 Say off if not sure, auto if TSX is in use but it should be used on safe 1904 platforms or on if TSX is in use and the security aspect of tsx is not 1905 relevant. 1906 1907config X86_INTEL_TSX_MODE_OFF 1908 bool "off" 1909 help 1910 TSX is disabled if possible - equals to tsx=off command line parameter. 1911 1912config X86_INTEL_TSX_MODE_ON 1913 bool "on" 1914 help 1915 TSX is always enabled on TSX capable HW - equals the tsx=on command 1916 line parameter. 1917 1918config X86_INTEL_TSX_MODE_AUTO 1919 bool "auto" 1920 help 1921 TSX is enabled on TSX capable HW that is believed to be safe against 1922 side channel attacks- equals the tsx=auto command line parameter. 1923endchoice 1924 1925config X86_SGX 1926 bool "Software Guard eXtensions (SGX)" 1927 depends on X86_64 && CPU_SUP_INTEL 1928 depends on CRYPTO=y 1929 depends on CRYPTO_SHA256=y 1930 select SRCU 1931 select MMU_NOTIFIER 1932 select NUMA_KEEP_MEMINFO if NUMA 1933 select XARRAY_MULTI 1934 help 1935 Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1936 that can be used by applications to set aside private regions of code 1937 and data, referred to as enclaves. An enclave's private memory can 1938 only be accessed by code running within the enclave. Accesses from 1939 outside the enclave, including other enclaves, are disallowed by 1940 hardware. 1941 1942 If unsure, say N. 1943 1944config EFI 1945 bool "EFI runtime service support" 1946 depends on ACPI 1947 select UCS2_STRING 1948 select EFI_RUNTIME_WRAPPERS 1949 select ARCH_USE_MEMREMAP_PROT 1950 help 1951 This enables the kernel to use EFI runtime services that are 1952 available (such as the EFI variable services). 1953 1954 This option is only useful on systems that have EFI firmware. 1955 In addition, you should use the latest ELILO loader available 1956 at <http://elilo.sourceforge.net> in order to take advantage 1957 of EFI runtime services. However, even with this option, the 1958 resultant kernel should continue to boot on existing non-EFI 1959 platforms. 1960 1961config EFI_STUB 1962 bool "EFI stub support" 1963 depends on EFI 1964 depends on $(cc-option,-mabi=ms) || X86_32 1965 select RELOCATABLE 1966 help 1967 This kernel feature allows a bzImage to be loaded directly 1968 by EFI firmware without the use of a bootloader. 1969 1970 See Documentation/admin-guide/efi-stub.rst for more information. 1971 1972config EFI_MIXED 1973 bool "EFI mixed-mode support" 1974 depends on EFI_STUB && X86_64 1975 help 1976 Enabling this feature allows a 64-bit kernel to be booted 1977 on a 32-bit firmware, provided that your CPU supports 64-bit 1978 mode. 1979 1980 Note that it is not possible to boot a mixed-mode enabled 1981 kernel via the EFI boot stub - a bootloader that supports 1982 the EFI handover protocol must be used. 1983 1984 If unsure, say N. 1985 1986source "kernel/Kconfig.hz" 1987 1988config KEXEC 1989 bool "kexec system call" 1990 select KEXEC_CORE 1991 help 1992 kexec is a system call that implements the ability to shutdown your 1993 current kernel, and to start another kernel. It is like a reboot 1994 but it is independent of the system firmware. And like a reboot 1995 you can start any kernel with it, not just Linux. 1996 1997 The name comes from the similarity to the exec system call. 1998 1999 It is an ongoing process to be certain the hardware in a machine 2000 is properly shutdown, so do not be surprised if this code does not 2001 initially work for you. As of this writing the exact hardware 2002 interface is strongly in flux, so no good recommendation can be 2003 made. 2004 2005config KEXEC_FILE 2006 bool "kexec file based system call" 2007 select KEXEC_CORE 2008 select BUILD_BIN2C 2009 depends on X86_64 2010 depends on CRYPTO=y 2011 depends on CRYPTO_SHA256=y 2012 help 2013 This is new version of kexec system call. This system call is 2014 file based and takes file descriptors as system call argument 2015 for kernel and initramfs as opposed to list of segments as 2016 accepted by previous system call. 2017 2018config ARCH_HAS_KEXEC_PURGATORY 2019 def_bool KEXEC_FILE 2020 2021config KEXEC_SIG 2022 bool "Verify kernel signature during kexec_file_load() syscall" 2023 depends on KEXEC_FILE 2024 help 2025 2026 This option makes the kexec_file_load() syscall check for a valid 2027 signature of the kernel image. The image can still be loaded without 2028 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 2029 there's a signature that we can check, then it must be valid. 2030 2031 In addition to this option, you need to enable signature 2032 verification for the corresponding kernel image type being 2033 loaded in order for this to work. 2034 2035config KEXEC_SIG_FORCE 2036 bool "Require a valid signature in kexec_file_load() syscall" 2037 depends on KEXEC_SIG 2038 help 2039 This option makes kernel signature verification mandatory for 2040 the kexec_file_load() syscall. 2041 2042config KEXEC_BZIMAGE_VERIFY_SIG 2043 bool "Enable bzImage signature verification support" 2044 depends on KEXEC_SIG 2045 depends on SIGNED_PE_FILE_VERIFICATION 2046 select SYSTEM_TRUSTED_KEYRING 2047 help 2048 Enable bzImage signature verification support. 2049 2050config CRASH_DUMP 2051 bool "kernel crash dumps" 2052 depends on X86_64 || (X86_32 && HIGHMEM) 2053 help 2054 Generate crash dump after being started by kexec. 2055 This should be normally only set in special crash dump kernels 2056 which are loaded in the main kernel with kexec-tools into 2057 a specially reserved region and then later executed after 2058 a crash by kdump/kexec. The crash dump kernel must be compiled 2059 to a memory address not used by the main kernel or BIOS using 2060 PHYSICAL_START, or it must be built as a relocatable image 2061 (CONFIG_RELOCATABLE=y). 2062 For more details see Documentation/admin-guide/kdump/kdump.rst 2063 2064config KEXEC_JUMP 2065 bool "kexec jump" 2066 depends on KEXEC && HIBERNATION 2067 help 2068 Jump between original kernel and kexeced kernel and invoke 2069 code in physical address mode via KEXEC 2070 2071config PHYSICAL_START 2072 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2073 default "0x1000000" 2074 help 2075 This gives the physical address where the kernel is loaded. 2076 2077 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2078 bzImage will decompress itself to above physical address and 2079 run from there. Otherwise, bzImage will run from the address where 2080 it has been loaded by the boot loader and will ignore above physical 2081 address. 2082 2083 In normal kdump cases one does not have to set/change this option 2084 as now bzImage can be compiled as a completely relocatable image 2085 (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2086 address. This option is mainly useful for the folks who don't want 2087 to use a bzImage for capturing the crash dump and want to use a 2088 vmlinux instead. vmlinux is not relocatable hence a kernel needs 2089 to be specifically compiled to run from a specific memory area 2090 (normally a reserved region) and this option comes handy. 2091 2092 So if you are using bzImage for capturing the crash dump, 2093 leave the value here unchanged to 0x1000000 and set 2094 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2095 for capturing the crash dump change this value to start of 2096 the reserved region. In other words, it can be set based on 2097 the "X" value as specified in the "crashkernel=YM@XM" 2098 command line boot parameter passed to the panic-ed 2099 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2100 for more details about crash dumps. 2101 2102 Usage of bzImage for capturing the crash dump is recommended as 2103 one does not have to build two kernels. Same kernel can be used 2104 as production kernel and capture kernel. Above option should have 2105 gone away after relocatable bzImage support is introduced. But it 2106 is present because there are users out there who continue to use 2107 vmlinux for dump capture. This option should go away down the 2108 line. 2109 2110 Don't change this unless you know what you are doing. 2111 2112config RELOCATABLE 2113 bool "Build a relocatable kernel" 2114 default y 2115 help 2116 This builds a kernel image that retains relocation information 2117 so it can be loaded someplace besides the default 1MB. 2118 The relocations tend to make the kernel binary about 10% larger, 2119 but are discarded at runtime. 2120 2121 One use is for the kexec on panic case where the recovery kernel 2122 must live at a different physical address than the primary 2123 kernel. 2124 2125 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2126 it has been loaded at and the compile time physical address 2127 (CONFIG_PHYSICAL_START) is used as the minimum location. 2128 2129config RANDOMIZE_BASE 2130 bool "Randomize the address of the kernel image (KASLR)" 2131 depends on RELOCATABLE 2132 default y 2133 help 2134 In support of Kernel Address Space Layout Randomization (KASLR), 2135 this randomizes the physical address at which the kernel image 2136 is decompressed and the virtual address where the kernel 2137 image is mapped, as a security feature that deters exploit 2138 attempts relying on knowledge of the location of kernel 2139 code internals. 2140 2141 On 64-bit, the kernel physical and virtual addresses are 2142 randomized separately. The physical address will be anywhere 2143 between 16MB and the top of physical memory (up to 64TB). The 2144 virtual address will be randomized from 16MB up to 1GB (9 bits 2145 of entropy). Note that this also reduces the memory space 2146 available to kernel modules from 1.5GB to 1GB. 2147 2148 On 32-bit, the kernel physical and virtual addresses are 2149 randomized together. They will be randomized from 16MB up to 2150 512MB (8 bits of entropy). 2151 2152 Entropy is generated using the RDRAND instruction if it is 2153 supported. If RDTSC is supported, its value is mixed into 2154 the entropy pool as well. If neither RDRAND nor RDTSC are 2155 supported, then entropy is read from the i8254 timer. The 2156 usable entropy is limited by the kernel being built using 2157 2GB addressing, and that PHYSICAL_ALIGN must be at a 2158 minimum of 2MB. As a result, only 10 bits of entropy are 2159 theoretically possible, but the implementations are further 2160 limited due to memory layouts. 2161 2162 If unsure, say Y. 2163 2164# Relocation on x86 needs some additional build support 2165config X86_NEED_RELOCS 2166 def_bool y 2167 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2168 2169config PHYSICAL_ALIGN 2170 hex "Alignment value to which kernel should be aligned" 2171 default "0x200000" 2172 range 0x2000 0x1000000 if X86_32 2173 range 0x200000 0x1000000 if X86_64 2174 help 2175 This value puts the alignment restrictions on physical address 2176 where kernel is loaded and run from. Kernel is compiled for an 2177 address which meets above alignment restriction. 2178 2179 If bootloader loads the kernel at a non-aligned address and 2180 CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2181 address aligned to above value and run from there. 2182 2183 If bootloader loads the kernel at a non-aligned address and 2184 CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2185 load address and decompress itself to the address it has been 2186 compiled for and run from there. The address for which kernel is 2187 compiled already meets above alignment restrictions. Hence the 2188 end result is that kernel runs from a physical address meeting 2189 above alignment restrictions. 2190 2191 On 32-bit this value must be a multiple of 0x2000. On 64-bit 2192 this value must be a multiple of 0x200000. 2193 2194 Don't change this unless you know what you are doing. 2195 2196config DYNAMIC_MEMORY_LAYOUT 2197 bool 2198 help 2199 This option makes base addresses of vmalloc and vmemmap as well as 2200 __PAGE_OFFSET movable during boot. 2201 2202config RANDOMIZE_MEMORY 2203 bool "Randomize the kernel memory sections" 2204 depends on X86_64 2205 depends on RANDOMIZE_BASE 2206 select DYNAMIC_MEMORY_LAYOUT 2207 default RANDOMIZE_BASE 2208 help 2209 Randomizes the base virtual address of kernel memory sections 2210 (physical memory mapping, vmalloc & vmemmap). This security feature 2211 makes exploits relying on predictable memory locations less reliable. 2212 2213 The order of allocations remains unchanged. Entropy is generated in 2214 the same way as RANDOMIZE_BASE. Current implementation in the optimal 2215 configuration have in average 30,000 different possible virtual 2216 addresses for each memory section. 2217 2218 If unsure, say Y. 2219 2220config RANDOMIZE_MEMORY_PHYSICAL_PADDING 2221 hex "Physical memory mapping padding" if EXPERT 2222 depends on RANDOMIZE_MEMORY 2223 default "0xa" if MEMORY_HOTPLUG 2224 default "0x0" 2225 range 0x1 0x40 if MEMORY_HOTPLUG 2226 range 0x0 0x40 2227 help 2228 Define the padding in terabytes added to the existing physical 2229 memory size during kernel memory randomization. It is useful 2230 for memory hotplug support but reduces the entropy available for 2231 address randomization. 2232 2233 If unsure, leave at the default value. 2234 2235config HOTPLUG_CPU 2236 def_bool y 2237 depends on SMP 2238 2239config BOOTPARAM_HOTPLUG_CPU0 2240 bool "Set default setting of cpu0_hotpluggable" 2241 depends on HOTPLUG_CPU 2242 help 2243 Set whether default state of cpu0_hotpluggable is on or off. 2244 2245 Say Y here to enable CPU0 hotplug by default. If this switch 2246 is turned on, there is no need to give cpu0_hotplug kernel 2247 parameter and the CPU0 hotplug feature is enabled by default. 2248 2249 Please note: there are two known CPU0 dependencies if you want 2250 to enable the CPU0 hotplug feature either by this switch or by 2251 cpu0_hotplug kernel parameter. 2252 2253 First, resume from hibernate or suspend always starts from CPU0. 2254 So hibernate and suspend are prevented if CPU0 is offline. 2255 2256 Second dependency is PIC interrupts always go to CPU0. CPU0 can not 2257 offline if any interrupt can not migrate out of CPU0. There may 2258 be other CPU0 dependencies. 2259 2260 Please make sure the dependencies are under your control before 2261 you enable this feature. 2262 2263 Say N if you don't want to enable CPU0 hotplug feature by default. 2264 You still can enable the CPU0 hotplug feature at boot by kernel 2265 parameter cpu0_hotplug. 2266 2267config DEBUG_HOTPLUG_CPU0 2268 def_bool n 2269 prompt "Debug CPU0 hotplug" 2270 depends on HOTPLUG_CPU 2271 help 2272 Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2273 soon as possible and boots up userspace with CPU0 offlined. User 2274 can online CPU0 back after boot time. 2275 2276 To debug CPU0 hotplug, you need to enable CPU0 offline/online 2277 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2278 compilation or giving cpu0_hotplug kernel parameter at boot. 2279 2280 If unsure, say N. 2281 2282config COMPAT_VDSO 2283 def_bool n 2284 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2285 depends on COMPAT_32 2286 help 2287 Certain buggy versions of glibc will crash if they are 2288 presented with a 32-bit vDSO that is not mapped at the address 2289 indicated in its segment table. 2290 2291 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2292 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2293 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2294 the only released version with the bug, but OpenSUSE 9 2295 contains a buggy "glibc 2.3.2". 2296 2297 The symptom of the bug is that everything crashes on startup, saying: 2298 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2299 2300 Saying Y here changes the default value of the vdso32 boot 2301 option from 1 to 0, which turns off the 32-bit vDSO entirely. 2302 This works around the glibc bug but hurts performance. 2303 2304 If unsure, say N: if you are compiling your own kernel, you 2305 are unlikely to be using a buggy version of glibc. 2306 2307choice 2308 prompt "vsyscall table for legacy applications" 2309 depends on X86_64 2310 default LEGACY_VSYSCALL_XONLY 2311 help 2312 Legacy user code that does not know how to find the vDSO expects 2313 to be able to issue three syscalls by calling fixed addresses in 2314 kernel space. Since this location is not randomized with ASLR, 2315 it can be used to assist security vulnerability exploitation. 2316 2317 This setting can be changed at boot time via the kernel command 2318 line parameter vsyscall=[emulate|xonly|none]. 2319 2320 On a system with recent enough glibc (2.14 or newer) and no 2321 static binaries, you can say None without a performance penalty 2322 to improve security. 2323 2324 If unsure, select "Emulate execution only". 2325 2326 config LEGACY_VSYSCALL_EMULATE 2327 bool "Full emulation" 2328 help 2329 The kernel traps and emulates calls into the fixed vsyscall 2330 address mapping. This makes the mapping non-executable, but 2331 it still contains readable known contents, which could be 2332 used in certain rare security vulnerability exploits. This 2333 configuration is recommended when using legacy userspace 2334 that still uses vsyscalls along with legacy binary 2335 instrumentation tools that require code to be readable. 2336 2337 An example of this type of legacy userspace is running 2338 Pin on an old binary that still uses vsyscalls. 2339 2340 config LEGACY_VSYSCALL_XONLY 2341 bool "Emulate execution only" 2342 help 2343 The kernel traps and emulates calls into the fixed vsyscall 2344 address mapping and does not allow reads. This 2345 configuration is recommended when userspace might use the 2346 legacy vsyscall area but support for legacy binary 2347 instrumentation of legacy code is not needed. It mitigates 2348 certain uses of the vsyscall area as an ASLR-bypassing 2349 buffer. 2350 2351 config LEGACY_VSYSCALL_NONE 2352 bool "None" 2353 help 2354 There will be no vsyscall mapping at all. This will 2355 eliminate any risk of ASLR bypass due to the vsyscall 2356 fixed address mapping. Attempts to use the vsyscalls 2357 will be reported to dmesg, so that either old or 2358 malicious userspace programs can be identified. 2359 2360endchoice 2361 2362config CMDLINE_BOOL 2363 bool "Built-in kernel command line" 2364 help 2365 Allow for specifying boot arguments to the kernel at 2366 build time. On some systems (e.g. embedded ones), it is 2367 necessary or convenient to provide some or all of the 2368 kernel boot arguments with the kernel itself (that is, 2369 to not rely on the boot loader to provide them.) 2370 2371 To compile command line arguments into the kernel, 2372 set this option to 'Y', then fill in the 2373 boot arguments in CONFIG_CMDLINE. 2374 2375 Systems with fully functional boot loaders (i.e. non-embedded) 2376 should leave this option set to 'N'. 2377 2378config CMDLINE 2379 string "Built-in kernel command string" 2380 depends on CMDLINE_BOOL 2381 default "" 2382 help 2383 Enter arguments here that should be compiled into the kernel 2384 image and used at boot time. If the boot loader provides a 2385 command line at boot time, it is appended to this string to 2386 form the full kernel command line, when the system boots. 2387 2388 However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2389 change this behavior. 2390 2391 In most cases, the command line (whether built-in or provided 2392 by the boot loader) should specify the device for the root 2393 file system. 2394 2395config CMDLINE_OVERRIDE 2396 bool "Built-in command line overrides boot loader arguments" 2397 depends on CMDLINE_BOOL && CMDLINE != "" 2398 help 2399 Set this option to 'Y' to have the kernel ignore the boot loader 2400 command line, and use ONLY the built-in command line. 2401 2402 This is used to work around broken boot loaders. This should 2403 be set to 'N' under normal conditions. 2404 2405config MODIFY_LDT_SYSCALL 2406 bool "Enable the LDT (local descriptor table)" if EXPERT 2407 default y 2408 help 2409 Linux can allow user programs to install a per-process x86 2410 Local Descriptor Table (LDT) using the modify_ldt(2) system 2411 call. This is required to run 16-bit or segmented code such as 2412 DOSEMU or some Wine programs. It is also used by some very old 2413 threading libraries. 2414 2415 Enabling this feature adds a small amount of overhead to 2416 context switches and increases the low-level kernel attack 2417 surface. Disabling it removes the modify_ldt(2) system call. 2418 2419 Saying 'N' here may make sense for embedded or server kernels. 2420 2421config STRICT_SIGALTSTACK_SIZE 2422 bool "Enforce strict size checking for sigaltstack" 2423 depends on DYNAMIC_SIGFRAME 2424 help 2425 For historical reasons MINSIGSTKSZ is a constant which became 2426 already too small with AVX512 support. Add a mechanism to 2427 enforce strict checking of the sigaltstack size against the 2428 real size of the FPU frame. This option enables the check 2429 by default. It can also be controlled via the kernel command 2430 line option 'strict_sas_size' independent of this config 2431 switch. Enabling it might break existing applications which 2432 allocate a too small sigaltstack but 'work' because they 2433 never get a signal delivered. 2434 2435 Say 'N' unless you want to really enforce this check. 2436 2437source "kernel/livepatch/Kconfig" 2438 2439endmenu 2440 2441config ARCH_HAS_ADD_PAGES 2442 def_bool y 2443 depends on ARCH_ENABLE_MEMORY_HOTPLUG 2444 2445config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 2446 def_bool y 2447 2448menu "Power management and ACPI options" 2449 2450config ARCH_HIBERNATION_HEADER 2451 def_bool y 2452 depends on HIBERNATION 2453 2454source "kernel/power/Kconfig" 2455 2456source "drivers/acpi/Kconfig" 2457 2458config X86_APM_BOOT 2459 def_bool y 2460 depends on APM 2461 2462menuconfig APM 2463 tristate "APM (Advanced Power Management) BIOS support" 2464 depends on X86_32 && PM_SLEEP 2465 help 2466 APM is a BIOS specification for saving power using several different 2467 techniques. This is mostly useful for battery powered laptops with 2468 APM compliant BIOSes. If you say Y here, the system time will be 2469 reset after a RESUME operation, the /proc/apm device will provide 2470 battery status information, and user-space programs will receive 2471 notification of APM "events" (e.g. battery status change). 2472 2473 If you select "Y" here, you can disable actual use of the APM 2474 BIOS by passing the "apm=off" option to the kernel at boot time. 2475 2476 Note that the APM support is almost completely disabled for 2477 machines with more than one CPU. 2478 2479 In order to use APM, you will need supporting software. For location 2480 and more information, read <file:Documentation/power/apm-acpi.rst> 2481 and the Battery Powered Linux mini-HOWTO, available from 2482 <http://www.tldp.org/docs.html#howto>. 2483 2484 This driver does not spin down disk drives (see the hdparm(8) 2485 manpage ("man 8 hdparm") for that), and it doesn't turn off 2486 VESA-compliant "green" monitors. 2487 2488 This driver does not support the TI 4000M TravelMate and the ACER 2489 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2490 desktop machines also don't have compliant BIOSes, and this driver 2491 may cause those machines to panic during the boot phase. 2492 2493 Generally, if you don't have a battery in your machine, there isn't 2494 much point in using this driver and you should say N. If you get 2495 random kernel OOPSes or reboots that don't seem to be related to 2496 anything, try disabling/enabling this option (or disabling/enabling 2497 APM in your BIOS). 2498 2499 Some other things you should try when experiencing seemingly random, 2500 "weird" problems: 2501 2502 1) make sure that you have enough swap space and that it is 2503 enabled. 2504 2) pass the "no-hlt" option to the kernel 2505 3) switch on floating point emulation in the kernel and pass 2506 the "no387" option to the kernel 2507 4) pass the "floppy=nodma" option to the kernel 2508 5) pass the "mem=4M" option to the kernel (thereby disabling 2509 all but the first 4 MB of RAM) 2510 6) make sure that the CPU is not over clocked. 2511 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2512 8) disable the cache from your BIOS settings 2513 9) install a fan for the video card or exchange video RAM 2514 10) install a better fan for the CPU 2515 11) exchange RAM chips 2516 12) exchange the motherboard. 2517 2518 To compile this driver as a module, choose M here: the 2519 module will be called apm. 2520 2521if APM 2522 2523config APM_IGNORE_USER_SUSPEND 2524 bool "Ignore USER SUSPEND" 2525 help 2526 This option will ignore USER SUSPEND requests. On machines with a 2527 compliant APM BIOS, you want to say N. However, on the NEC Versa M 2528 series notebooks, it is necessary to say Y because of a BIOS bug. 2529 2530config APM_DO_ENABLE 2531 bool "Enable PM at boot time" 2532 help 2533 Enable APM features at boot time. From page 36 of the APM BIOS 2534 specification: "When disabled, the APM BIOS does not automatically 2535 power manage devices, enter the Standby State, enter the Suspend 2536 State, or take power saving steps in response to CPU Idle calls." 2537 This driver will make CPU Idle calls when Linux is idle (unless this 2538 feature is turned off -- see "Do CPU IDLE calls", below). This 2539 should always save battery power, but more complicated APM features 2540 will be dependent on your BIOS implementation. You may need to turn 2541 this option off if your computer hangs at boot time when using APM 2542 support, or if it beeps continuously instead of suspending. Turn 2543 this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2544 T400CDT. This is off by default since most machines do fine without 2545 this feature. 2546 2547config APM_CPU_IDLE 2548 depends on CPU_IDLE 2549 bool "Make CPU Idle calls when idle" 2550 help 2551 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2552 On some machines, this can activate improved power savings, such as 2553 a slowed CPU clock rate, when the machine is idle. These idle calls 2554 are made after the idle loop has run for some length of time (e.g., 2555 333 mS). On some machines, this will cause a hang at boot time or 2556 whenever the CPU becomes idle. (On machines with more than one CPU, 2557 this option does nothing.) 2558 2559config APM_DISPLAY_BLANK 2560 bool "Enable console blanking using APM" 2561 help 2562 Enable console blanking using the APM. Some laptops can use this to 2563 turn off the LCD backlight when the screen blanker of the Linux 2564 virtual console blanks the screen. Note that this is only used by 2565 the virtual console screen blanker, and won't turn off the backlight 2566 when using the X Window system. This also doesn't have anything to 2567 do with your VESA-compliant power-saving monitor. Further, this 2568 option doesn't work for all laptops -- it might not turn off your 2569 backlight at all, or it might print a lot of errors to the console, 2570 especially if you are using gpm. 2571 2572config APM_ALLOW_INTS 2573 bool "Allow interrupts during APM BIOS calls" 2574 help 2575 Normally we disable external interrupts while we are making calls to 2576 the APM BIOS as a measure to lessen the effects of a badly behaving 2577 BIOS implementation. The BIOS should reenable interrupts if it 2578 needs to. Unfortunately, some BIOSes do not -- especially those in 2579 many of the newer IBM Thinkpads. If you experience hangs when you 2580 suspend, try setting this to Y. Otherwise, say N. 2581 2582endif # APM 2583 2584source "drivers/cpufreq/Kconfig" 2585 2586source "drivers/cpuidle/Kconfig" 2587 2588source "drivers/idle/Kconfig" 2589 2590endmenu 2591 2592 2593menu "Bus options (PCI etc.)" 2594 2595choice 2596 prompt "PCI access mode" 2597 depends on X86_32 && PCI 2598 default PCI_GOANY 2599 help 2600 On PCI systems, the BIOS can be used to detect the PCI devices and 2601 determine their configuration. However, some old PCI motherboards 2602 have BIOS bugs and may crash if this is done. Also, some embedded 2603 PCI-based systems don't have any BIOS at all. Linux can also try to 2604 detect the PCI hardware directly without using the BIOS. 2605 2606 With this option, you can specify how Linux should detect the 2607 PCI devices. If you choose "BIOS", the BIOS will be used, 2608 if you choose "Direct", the BIOS won't be used, and if you 2609 choose "MMConfig", then PCI Express MMCONFIG will be used. 2610 If you choose "Any", the kernel will try MMCONFIG, then the 2611 direct access method and falls back to the BIOS if that doesn't 2612 work. If unsure, go with the default, which is "Any". 2613 2614config PCI_GOBIOS 2615 bool "BIOS" 2616 2617config PCI_GOMMCONFIG 2618 bool "MMConfig" 2619 2620config PCI_GODIRECT 2621 bool "Direct" 2622 2623config PCI_GOOLPC 2624 bool "OLPC XO-1" 2625 depends on OLPC 2626 2627config PCI_GOANY 2628 bool "Any" 2629 2630endchoice 2631 2632config PCI_BIOS 2633 def_bool y 2634 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2635 2636# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2637config PCI_DIRECT 2638 def_bool y 2639 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2640 2641config PCI_MMCONFIG 2642 bool "Support mmconfig PCI config space access" if X86_64 2643 default y 2644 depends on PCI && (ACPI || JAILHOUSE_GUEST) 2645 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2646 2647config PCI_OLPC 2648 def_bool y 2649 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 2650 2651config PCI_XEN 2652 def_bool y 2653 depends on PCI && XEN 2654 2655config MMCONF_FAM10H 2656 def_bool y 2657 depends on X86_64 && PCI_MMCONFIG && ACPI 2658 2659config PCI_CNB20LE_QUIRK 2660 bool "Read CNB20LE Host Bridge Windows" if EXPERT 2661 depends on PCI 2662 help 2663 Read the PCI windows out of the CNB20LE host bridge. This allows 2664 PCI hotplug to work on systems with the CNB20LE chipset which do 2665 not have ACPI. 2666 2667 There's no public spec for this chipset, and this functionality 2668 is known to be incomplete. 2669 2670 You should say N unless you know you need this. 2671 2672config ISA_BUS 2673 bool "ISA bus support on modern systems" if EXPERT 2674 help 2675 Expose ISA bus device drivers and options available for selection and 2676 configuration. Enable this option if your target machine has an ISA 2677 bus. ISA is an older system, displaced by PCI and newer bus 2678 architectures -- if your target machine is modern, it probably does 2679 not have an ISA bus. 2680 2681 If unsure, say N. 2682 2683# x86_64 have no ISA slots, but can have ISA-style DMA. 2684config ISA_DMA_API 2685 bool "ISA-style DMA support" if (X86_64 && EXPERT) 2686 default y 2687 help 2688 Enables ISA-style DMA support for devices requiring such controllers. 2689 If unsure, say Y. 2690 2691if X86_32 2692 2693config ISA 2694 bool "ISA support" 2695 help 2696 Find out whether you have ISA slots on your motherboard. ISA is the 2697 name of a bus system, i.e. the way the CPU talks to the other stuff 2698 inside your box. Other bus systems are PCI, EISA, MicroChannel 2699 (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2700 newer boards don't support it. If you have ISA, say Y, otherwise N. 2701 2702config SCx200 2703 tristate "NatSemi SCx200 support" 2704 help 2705 This provides basic support for National Semiconductor's 2706 (now AMD's) Geode processors. The driver probes for the 2707 PCI-IDs of several on-chip devices, so its a good dependency 2708 for other scx200_* drivers. 2709 2710 If compiled as a module, the driver is named scx200. 2711 2712config SCx200HR_TIMER 2713 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2714 depends on SCx200 2715 default y 2716 help 2717 This driver provides a clocksource built upon the on-chip 2718 27MHz high-resolution timer. Its also a workaround for 2719 NSC Geode SC-1100's buggy TSC, which loses time when the 2720 processor goes idle (as is done by the scheduler). The 2721 other workaround is idle=poll boot option. 2722 2723config OLPC 2724 bool "One Laptop Per Child support" 2725 depends on !X86_PAE 2726 select GPIOLIB 2727 select OF 2728 select OF_PROMTREE 2729 select IRQ_DOMAIN 2730 select OLPC_EC 2731 help 2732 Add support for detecting the unique features of the OLPC 2733 XO hardware. 2734 2735config OLPC_XO1_PM 2736 bool "OLPC XO-1 Power Management" 2737 depends on OLPC && MFD_CS5535=y && PM_SLEEP 2738 help 2739 Add support for poweroff and suspend of the OLPC XO-1 laptop. 2740 2741config OLPC_XO1_RTC 2742 bool "OLPC XO-1 Real Time Clock" 2743 depends on OLPC_XO1_PM && RTC_DRV_CMOS 2744 help 2745 Add support for the XO-1 real time clock, which can be used as a 2746 programmable wakeup source. 2747 2748config OLPC_XO1_SCI 2749 bool "OLPC XO-1 SCI extras" 2750 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2751 depends on INPUT=y 2752 select POWER_SUPPLY 2753 help 2754 Add support for SCI-based features of the OLPC XO-1 laptop: 2755 - EC-driven system wakeups 2756 - Power button 2757 - Ebook switch 2758 - Lid switch 2759 - AC adapter status updates 2760 - Battery status updates 2761 2762config OLPC_XO15_SCI 2763 bool "OLPC XO-1.5 SCI extras" 2764 depends on OLPC && ACPI 2765 select POWER_SUPPLY 2766 help 2767 Add support for SCI-based features of the OLPC XO-1.5 laptop: 2768 - EC-driven system wakeups 2769 - AC adapter status updates 2770 - Battery status updates 2771 2772config ALIX 2773 bool "PCEngines ALIX System Support (LED setup)" 2774 select GPIOLIB 2775 help 2776 This option enables system support for the PCEngines ALIX. 2777 At present this just sets up LEDs for GPIO control on 2778 ALIX2/3/6 boards. However, other system specific setup should 2779 get added here. 2780 2781 Note: You must still enable the drivers for GPIO and LED support 2782 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2783 2784 Note: You have to set alix.force=1 for boards with Award BIOS. 2785 2786config NET5501 2787 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2788 select GPIOLIB 2789 help 2790 This option enables system support for the Soekris Engineering net5501. 2791 2792config GEOS 2793 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 2794 select GPIOLIB 2795 depends on DMI 2796 help 2797 This option enables system support for the Traverse Technologies GEOS. 2798 2799config TS5500 2800 bool "Technologic Systems TS-5500 platform support" 2801 depends on MELAN 2802 select CHECK_SIGNATURE 2803 select NEW_LEDS 2804 select LEDS_CLASS 2805 help 2806 This option enables system support for the Technologic Systems TS-5500. 2807 2808endif # X86_32 2809 2810config AMD_NB 2811 def_bool y 2812 depends on CPU_SUP_AMD && PCI 2813 2814endmenu 2815 2816 2817menu "Binary Emulations" 2818 2819config IA32_EMULATION 2820 bool "IA32 Emulation" 2821 depends on X86_64 2822 select ARCH_WANT_OLD_COMPAT_IPC 2823 select BINFMT_ELF 2824 select COMPAT_OLD_SIGACTION 2825 help 2826 Include code to run legacy 32-bit programs under a 2827 64-bit kernel. You should likely turn this on, unless you're 2828 100% sure that you don't have any 32-bit programs left. 2829 2830config IA32_AOUT 2831 tristate "IA32 a.out support" 2832 depends on IA32_EMULATION 2833 depends on BROKEN 2834 help 2835 Support old a.out binaries in the 32bit emulation. 2836 2837config X86_X32 2838 bool "x32 ABI for 64-bit mode" 2839 depends on X86_64 2840 help 2841 Include code to run binaries for the x32 native 32-bit ABI 2842 for 64-bit processors. An x32 process gets access to the 2843 full 64-bit register file and wide data path while leaving 2844 pointers at 32 bits for smaller memory footprint. 2845 2846 You will need a recent binutils (2.22 or later) with 2847 elf32_x86_64 support enabled to compile a kernel with this 2848 option set. 2849 2850config COMPAT_32 2851 def_bool y 2852 depends on IA32_EMULATION || X86_32 2853 select HAVE_UID16 2854 select OLD_SIGSUSPEND3 2855 2856config COMPAT 2857 def_bool y 2858 depends on IA32_EMULATION || X86_X32 2859 2860if COMPAT 2861config COMPAT_FOR_U64_ALIGNMENT 2862 def_bool y 2863 2864config SYSVIPC_COMPAT 2865 def_bool y 2866 depends on SYSVIPC 2867endif 2868 2869endmenu 2870 2871 2872config HAVE_ATOMIC_IOMAP 2873 def_bool y 2874 depends on X86_32 2875 2876source "arch/x86/kvm/Kconfig" 2877 2878source "arch/x86/Kconfig.assembler" 2879