1b2441318SGreg Kroah-Hartman# SPDX-License-Identifier: GPL-2.0 2daa93fabSSam Ravnborg# Select 32 or 64 bit 3daa93fabSSam Ravnborgconfig 64BIT 4104daea1SMasahiro Yamada bool "64-bit kernel" if "$(ARCH)" = "x86" 5104daea1SMasahiro Yamada default "$(ARCH)" != "i386" 6a7f7f624SMasahiro Yamada help 7daa93fabSSam Ravnborg Say yes to build a 64-bit kernel - formerly known as x86_64 8daa93fabSSam Ravnborg Say no to build a 32-bit kernel - formerly known as i386 9daa93fabSSam Ravnborg 10daa93fabSSam Ravnborgconfig X86_32 113120e25eSJan Beulich def_bool y 123120e25eSJan Beulich depends on !64BIT 13341c787eSIngo Molnar # Options that are inherently 32-bit kernel only: 14341c787eSIngo Molnar select ARCH_WANT_IPC_PARSE_VERSION 15341c787eSIngo Molnar select CLKSRC_I8253 16341c787eSIngo Molnar select CLONE_BACKWARDS 17117ed454SThomas Gleixner select HAVE_DEBUG_STACKOVERFLOW 18341c787eSIngo Molnar select MODULES_USE_ELF_REL 19341c787eSIngo Molnar select OLD_SIGACTION 207ac87074SVincenzo Frascino select GENERIC_VDSO_32 21daa93fabSSam Ravnborg 22daa93fabSSam Ravnborgconfig X86_64 233120e25eSJan Beulich def_bool y 243120e25eSJan Beulich depends on 64BIT 25d94e0685SIngo Molnar # Options that are inherently 64-bit kernel only: 264eb0716eSAlexandre Ghiti select ARCH_HAS_GIGANTIC_PAGE 27c12d3362SArd Biesheuvel select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 28d94e0685SIngo Molnar select ARCH_USE_CMPXCHG_LOCKREF 29d94e0685SIngo Molnar select HAVE_ARCH_SOFT_DIRTY 30d94e0685SIngo Molnar select MODULES_USE_ELF_RELA 31f616ab59SChristoph Hellwig select NEED_DMA_MAP_STATE 3209230cbcSChristoph Hellwig select SWIOTLB 331032c0baSSam Ravnborg 34518049d9SSteven Rostedt (VMware)config FORCE_DYNAMIC_FTRACE 35518049d9SSteven Rostedt (VMware) def_bool y 36518049d9SSteven Rostedt (VMware) depends on X86_32 37518049d9SSteven Rostedt (VMware) depends on FUNCTION_TRACER 38518049d9SSteven Rostedt (VMware) select DYNAMIC_FTRACE 39518049d9SSteven Rostedt (VMware) help 40518049d9SSteven Rostedt (VMware) We keep the static function tracing (!DYNAMIC_FTRACE) around 41518049d9SSteven Rostedt (VMware) in order to test the non static function tracing in the 42518049d9SSteven Rostedt (VMware) generic code, as other architectures still use it. But we 43518049d9SSteven Rostedt (VMware) only need to keep it around for x86_64. No need to keep it 44518049d9SSteven Rostedt (VMware) for x86_32. For x86_32, force DYNAMIC_FTRACE. 45d94e0685SIngo Molnar# 46d94e0685SIngo Molnar# Arch settings 47d94e0685SIngo Molnar# 48d94e0685SIngo Molnar# ( Note that options that are marked 'if X86_64' could in principle be 49d94e0685SIngo Molnar# ported to 32-bit as well. ) 50d94e0685SIngo Molnar# 518d5fffb9SSam Ravnborgconfig X86 523c2362e6SHarvey Harrison def_bool y 53c763ea26SIngo Molnar # 54c763ea26SIngo Molnar # Note: keep this list sorted alphabetically 55c763ea26SIngo Molnar # 566471b825SIngo Molnar select ACPI_LEGACY_TABLES_LOOKUP if ACPI 576e0a0ea1SGraeme Gregory select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 58942fa985SYury Norov select ARCH_32BIT_OFF_T if X86_32 592a21ad57SThomas Gleixner select ARCH_CLOCKSOURCE_INIT 6091dda51aSAleksey Makarov select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 61fa5b6ec9SLaura Abbott select ARCH_HAS_DEBUG_VIRTUAL 62399145f9SAnshuman Khandual select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 6321266be9SDan Williams select ARCH_HAS_DEVMEM_IS_ALLOWED 64b1a57bbfSDouglas Anderson select ARCH_HAS_EARLY_DEBUG if KGDB 656471b825SIngo Molnar select ARCH_HAS_ELF_RANDOMIZE 6672d93104SLinus Torvalds select ARCH_HAS_FAST_MULTIPLIER 67316d097cSDave Hansen select ARCH_HAS_FILTER_PGPROT 686974f0c4SDaniel Micay select ARCH_HAS_FORTIFY_SOURCE 69957e3facSRiku Voipio select ARCH_HAS_GCOV_PROFILE_ALL 700f1441b4SPeter Zijlstra select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION 710c9c1d56SThiago Jung Bauermann select ARCH_HAS_MEM_ENCRYPT 7210bcc80eSMathieu Desnoyers select ARCH_HAS_MEMBARRIER_SYNC_CORE 730ebeea8cSDaniel Borkmann select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 74c763ea26SIngo Molnar select ARCH_HAS_PMEM_API if X86_64 7517596731SRobin Murphy select ARCH_HAS_PTE_DEVMAP if X86_64 763010a5eaSLaurent Dufour select ARCH_HAS_PTE_SPECIAL 770aed55afSDan Williams select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 78092b31aaSDan Williams select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE 79d2852a22SDaniel Borkmann select ARCH_HAS_SET_MEMORY 80d253ca0cSRick Edgecombe select ARCH_HAS_SET_DIRECT_MAP 81ad21fc4fSLaura Abbott select ARCH_HAS_STRICT_KERNEL_RWX 82ad21fc4fSLaura Abbott select ARCH_HAS_STRICT_MODULE_RWX 83ac1ab12aSMathieu Desnoyers select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 8425c619e5SBrian Gerst select ARCH_HAS_SYSCALL_WRAPPER 85c6d30853SAndrey Ryabinin select ARCH_HAS_UBSAN_SANITIZE_ALL 867e01ccb4SZong Li select ARCH_HAS_DEBUG_WX 876471b825SIngo Molnar select ARCH_HAVE_NMI_SAFE_CMPXCHG 886471b825SIngo Molnar select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 8977fbbc81SMark Salter select ARCH_MIGHT_HAVE_PC_PARPORT 905e2c18c0SMark Salter select ARCH_MIGHT_HAVE_PC_SERIO 913599fe12SThomas Gleixner select ARCH_STACKWALK 922c870e61SArnd Bergmann select ARCH_SUPPORTS_ACPI 936471b825SIngo Molnar select ARCH_SUPPORTS_ATOMIC_RMW 946471b825SIngo Molnar select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 956471b825SIngo Molnar select ARCH_USE_BUILTIN_BSWAP 966471b825SIngo Molnar select ARCH_USE_QUEUED_RWLOCKS 976471b825SIngo Molnar select ARCH_USE_QUEUED_SPINLOCKS 982ce0d7f9SMark Brown select ARCH_USE_SYM_ANNOTATIONS 99ce4a4e56SAndy Lutomirski select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 10081c22041SDaniel Borkmann select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 101c763ea26SIngo Molnar select ARCH_WANTS_DYNAMIC_TASK_STRUCT 1023876d4a3SAlexandre Ghiti select ARCH_WANT_HUGE_PMD_SHARE 10338d8b4e6SHuang Ying select ARCH_WANTS_THP_SWAP if X86_64 10410916706SShile Zhang select BUILDTIME_TABLE_SORT 1056471b825SIngo Molnar select CLKEVT_I8253 1066471b825SIngo Molnar select CLOCKSOURCE_VALIDATE_LAST_CYCLE 1076471b825SIngo Molnar select CLOCKSOURCE_WATCHDOG 1086471b825SIngo Molnar select DCACHE_WORD_ACCESS 10945471cd9SLinus Torvalds select EDAC_ATOMIC_SCRUB 11045471cd9SLinus Torvalds select EDAC_SUPPORT 1116471b825SIngo Molnar select GENERIC_CLOCKEVENTS 1126471b825SIngo Molnar select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 1136471b825SIngo Molnar select GENERIC_CLOCKEVENTS_MIN_ADJUST 1146471b825SIngo Molnar select GENERIC_CMOS_UPDATE 1156471b825SIngo Molnar select GENERIC_CPU_AUTOPROBE 11661dc0f55SThomas Gleixner select GENERIC_CPU_VULNERABILITIES 1176471b825SIngo Molnar select GENERIC_EARLY_IOREMAP 11827d6b4d1SThomas Gleixner select GENERIC_ENTRY 1196471b825SIngo Molnar select GENERIC_FIND_FIRST_BIT 1206471b825SIngo Molnar select GENERIC_IOMAP 121c7d6c9ddSThomas Gleixner select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 1220fa115daSThomas Gleixner select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 123ad7a929fSThomas Gleixner select GENERIC_IRQ_MIGRATION if SMP 1246471b825SIngo Molnar select GENERIC_IRQ_PROBE 125c201c917SThomas Gleixner select GENERIC_IRQ_RESERVATION_MODE 1266471b825SIngo Molnar select GENERIC_IRQ_SHOW 1276471b825SIngo Molnar select GENERIC_PENDING_IRQ if SMP 1282ae27137SSteven Price select GENERIC_PTDUMP 1296471b825SIngo Molnar select GENERIC_SMP_IDLE_THREAD 1306471b825SIngo Molnar select GENERIC_STRNCPY_FROM_USER 1316471b825SIngo Molnar select GENERIC_STRNLEN_USER 1326471b825SIngo Molnar select GENERIC_TIME_VSYSCALL 1337ac87074SVincenzo Frascino select GENERIC_GETTIMEOFDAY 134550a77a7SDmitry Safonov select GENERIC_VDSO_TIME_NS 13539656e83SChristoph Hellwig select GUP_GET_PTE_LOW_HIGH if X86_PAE 13617e5888eSHans de Goede select HARDIRQS_SW_RESEND 1377edaeb68SThomas Gleixner select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 1386471b825SIngo Molnar select HAVE_ACPI_APEI if ACPI 1396471b825SIngo Molnar select HAVE_ACPI_APEI_NMI if ACPI 1406471b825SIngo Molnar select HAVE_ALIGNED_STRUCT_PAGE if SLUB 1416471b825SIngo Molnar select HAVE_ARCH_AUDITSYSCALL 1426471b825SIngo Molnar select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 1436471b825SIngo Molnar select HAVE_ARCH_JUMP_LABEL 144b34006c4SArd Biesheuvel select HAVE_ARCH_JUMP_LABEL_RELATIVE 145d17a1d97SAndrey Ryabinin select HAVE_ARCH_KASAN if X86_64 1460609ae01SDaniel Axtens select HAVE_ARCH_KASAN_VMALLOC if X86_64 1476471b825SIngo Molnar select HAVE_ARCH_KGDB 1489e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_BITS if MMU 1499e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 1501b028f78SDmitry Safonov select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 151271ca788SArd Biesheuvel select HAVE_ARCH_PREL32_RELOCATIONS 1526471b825SIngo Molnar select HAVE_ARCH_SECCOMP_FILTER 153f7d83c1cSKees Cook select HAVE_ARCH_THREAD_STRUCT_WHITELIST 154afaef01cSAlexander Popov select HAVE_ARCH_STACKLEAK 1556471b825SIngo Molnar select HAVE_ARCH_TRACEHOOK 1566471b825SIngo Molnar select HAVE_ARCH_TRANSPARENT_HUGEPAGE 157a00cc7d9SMatthew Wilcox select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 158b64d8d1eSPeter Xu select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 159e37e43a4SAndy Lutomirski select HAVE_ARCH_VMAP_STACK if X86_64 160c763ea26SIngo Molnar select HAVE_ARCH_WITHIN_STACK_FRAMES 1612ff2b7ecSMasahiro Yamada select HAVE_ASM_MODVERSIONS 1626471b825SIngo Molnar select HAVE_CMPXCHG_DOUBLE 1636471b825SIngo Molnar select HAVE_CMPXCHG_LOCAL 1646471b825SIngo Molnar select HAVE_CONTEXT_TRACKING if X86_64 1656471b825SIngo Molnar select HAVE_C_RECORDMCOUNT 1666471b825SIngo Molnar select HAVE_DEBUG_KMEMLEAK 1679c5a3621SAkinobu Mita select HAVE_DMA_CONTIGUOUS 168677aa9f7SSteven Rostedt select HAVE_DYNAMIC_FTRACE 16906aeaaeaSMasami Hiramatsu select HAVE_DYNAMIC_FTRACE_WITH_REGS 170562955feSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 17103f5781bSWang YanQing select HAVE_EBPF_JIT 17258340a07SJohannes Berg select HAVE_EFFICIENT_UNALIGNED_ACCESS 1736630a8e5SChristoph Hellwig select HAVE_EISA 1745f56a5dfSJiri Slaby select HAVE_EXIT_THREAD 17567a929e0SChristoph Hellwig select HAVE_FAST_GUP 176644e0e8dSSteven Rostedt (VMware) select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 1776471b825SIngo Molnar select HAVE_FTRACE_MCOUNT_RECORD 1786471b825SIngo Molnar select HAVE_FUNCTION_GRAPH_TRACER 1796471b825SIngo Molnar select HAVE_FUNCTION_TRACER 1806b90bd4bSEmese Revfy select HAVE_GCC_PLUGINS 1810067f129SK.Prasad select HAVE_HW_BREAKPOINT 1826471b825SIngo Molnar select HAVE_IDE 1836471b825SIngo Molnar select HAVE_IOREMAP_PROT 1846471b825SIngo Molnar select HAVE_IRQ_TIME_ACCOUNTING 1856471b825SIngo Molnar select HAVE_KERNEL_BZIP2 1866471b825SIngo Molnar select HAVE_KERNEL_GZIP 1876471b825SIngo Molnar select HAVE_KERNEL_LZ4 1886471b825SIngo Molnar select HAVE_KERNEL_LZMA 1896471b825SIngo Molnar select HAVE_KERNEL_LZO 1906471b825SIngo Molnar select HAVE_KERNEL_XZ 191fb46d057SNick Terrell select HAVE_KERNEL_ZSTD 1926471b825SIngo Molnar select HAVE_KPROBES 1936471b825SIngo Molnar select HAVE_KPROBES_ON_FTRACE 194540adea3SMasami Hiramatsu select HAVE_FUNCTION_ERROR_INJECTION 1956471b825SIngo Molnar select HAVE_KRETPROBES 1966471b825SIngo Molnar select HAVE_KVM 1976471b825SIngo Molnar select HAVE_LIVEPATCH if X86_64 1980102752eSFrederic Weisbecker select HAVE_MIXED_BREAKPOINTS_REGS 199ee9f8fceSJosh Poimboeuf select HAVE_MOD_ARCH_SPECIFIC 2009f132f7eSJoel Fernandes (Google) select HAVE_MOVE_PMD 20142a0bb3fSPetr Mladek select HAVE_NMI 2026471b825SIngo Molnar select HAVE_OPROFILE 2036471b825SIngo Molnar select HAVE_OPTPROBES 2046471b825SIngo Molnar select HAVE_PCSPKR_PLATFORM 2056471b825SIngo Molnar select HAVE_PERF_EVENTS 206c01d4323SFrederic Weisbecker select HAVE_PERF_EVENTS_NMI 20792e5aae4SNicholas Piggin select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 208eb01d42aSChristoph Hellwig select HAVE_PCI 209c5e63197SJiri Olsa select HAVE_PERF_REGS 210c5ebcedbSJiri Olsa select HAVE_PERF_USER_STACK_DUMP 211ff2e6d72SPeter Zijlstra select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 21200998085SThomas Gleixner select HAVE_POSIX_CPU_TIMERS_TASK_WORK 2136471b825SIngo Molnar select HAVE_REGS_AND_STACK_ACCESS_API 2146415b38bSJiri Slaby select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION 2153c88ee19SMasami Hiramatsu select HAVE_FUNCTION_ARG_ACCESS_API 216d148eac0SMasahiro Yamada select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 217c763ea26SIngo Molnar select HAVE_STACK_VALIDATION if X86_64 218d6761b8fSMathieu Desnoyers select HAVE_RSEQ 2196471b825SIngo Molnar select HAVE_SYSCALL_TRACEPOINTS 2206471b825SIngo Molnar select HAVE_UNSTABLE_SCHED_CLOCK 2217c68af6eSAvi Kivity select HAVE_USER_RETURN_NOTIFIER 2227ac87074SVincenzo Frascino select HAVE_GENERIC_VDSO 22305736e4aSThomas Gleixner select HOTPLUG_SMT if SMP 224c0185808SThomas Gleixner select IRQ_FORCED_THREADING 22586596f0aSChristoph Hellwig select NEED_SG_DMA_LENGTH 2262eac9c2dSChristoph Hellwig select PCI_DOMAINS if PCI 227625210cfSSinan Kaya select PCI_LOCKLESS_CONFIG if PCI 2286471b825SIngo Molnar select PERF_EVENTS 2293195ef59SPrarit Bhargava select RTC_LIB 230d6faca40SArnd Bergmann select RTC_MC146818_LIB 2316471b825SIngo Molnar select SPARSE_IRQ 23283fe27eaSPranith Kumar select SRCU 2336471b825SIngo Molnar select SYSCTL_EXCEPTION_TRACE 23415f4eae7SAndy Lutomirski select THREAD_INFO_IN_TASK 2356471b825SIngo Molnar select USER_STACKTRACE_SUPPORT 2366471b825SIngo Molnar select VIRT_TO_BUS 2373b02a051SIngo Molnar select HAVE_ARCH_KCSAN if X86_64 2386471b825SIngo Molnar select X86_FEATURE_NAMES if PROC_FS 2390c608dadSAubrey Li select PROC_PID_ARCH_STATUS if PROC_FS 2409e2b4be3SNayna Jain imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 2417d8330a5SBalbir Singh 242ba7e4d13SIngo Molnarconfig INSTRUCTION_DECODER 2433120e25eSJan Beulich def_bool y 2443120e25eSJan Beulich depends on KPROBES || PERF_EVENTS || UPROBES 245ba7e4d13SIngo Molnar 24651b26adaSLinus Torvaldsconfig OUTPUT_FORMAT 24751b26adaSLinus Torvalds string 24851b26adaSLinus Torvalds default "elf32-i386" if X86_32 24951b26adaSLinus Torvalds default "elf64-x86-64" if X86_64 25051b26adaSLinus Torvalds 2518d5fffb9SSam Ravnborgconfig LOCKDEP_SUPPORT 2523c2362e6SHarvey Harrison def_bool y 2538d5fffb9SSam Ravnborg 2548d5fffb9SSam Ravnborgconfig STACKTRACE_SUPPORT 2553c2362e6SHarvey Harrison def_bool y 2568d5fffb9SSam Ravnborg 2578d5fffb9SSam Ravnborgconfig MMU 2583c2362e6SHarvey Harrison def_bool y 2598d5fffb9SSam Ravnborg 2609e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MIN 2619e08f57dSDaniel Cashman default 28 if 64BIT 2629e08f57dSDaniel Cashman default 8 2639e08f57dSDaniel Cashman 2649e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MAX 2659e08f57dSDaniel Cashman default 32 if 64BIT 2669e08f57dSDaniel Cashman default 16 2679e08f57dSDaniel Cashman 2689e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MIN 2699e08f57dSDaniel Cashman default 8 2709e08f57dSDaniel Cashman 2719e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MAX 2729e08f57dSDaniel Cashman default 16 2739e08f57dSDaniel Cashman 2748d5fffb9SSam Ravnborgconfig SBUS 2758d5fffb9SSam Ravnborg bool 2768d5fffb9SSam Ravnborg 2778d5fffb9SSam Ravnborgconfig GENERIC_ISA_DMA 2783120e25eSJan Beulich def_bool y 2793120e25eSJan Beulich depends on ISA_DMA_API 2808d5fffb9SSam Ravnborg 2818d5fffb9SSam Ravnborgconfig GENERIC_BUG 2823c2362e6SHarvey Harrison def_bool y 2838d5fffb9SSam Ravnborg depends on BUG 284b93a531eSJan Beulich select GENERIC_BUG_RELATIVE_POINTERS if X86_64 285b93a531eSJan Beulich 286b93a531eSJan Beulichconfig GENERIC_BUG_RELATIVE_POINTERS 287b93a531eSJan Beulich bool 2888d5fffb9SSam Ravnborg 2898d5fffb9SSam Ravnborgconfig ARCH_MAY_HAVE_PC_FDC 2903120e25eSJan Beulich def_bool y 2913120e25eSJan Beulich depends on ISA_DMA_API 2928d5fffb9SSam Ravnborg 2931032c0baSSam Ravnborgconfig GENERIC_CALIBRATE_DELAY 2941032c0baSSam Ravnborg def_bool y 2951032c0baSSam Ravnborg 2969a0b8415Svenkatesh.pallipadi@intel.comconfig ARCH_HAS_CPU_RELAX 2979a0b8415Svenkatesh.pallipadi@intel.com def_bool y 2988d5fffb9SSam Ravnborg 2991b27d05bSPekka Enbergconfig ARCH_HAS_CACHE_LINE_SIZE 3001b27d05bSPekka Enberg def_bool y 3011b27d05bSPekka Enberg 302316d097cSDave Hansenconfig ARCH_HAS_FILTER_PGPROT 303316d097cSDave Hansen def_bool y 304316d097cSDave Hansen 305dd5af90aSMike Travisconfig HAVE_SETUP_PER_CPU_AREA 30689c9c4c5SBrian Gerst def_bool y 307b32ef636Stravis@sgi.com 30808fc4580STejun Heoconfig NEED_PER_CPU_EMBED_FIRST_CHUNK 30908fc4580STejun Heo def_bool y 31008fc4580STejun Heo 31108fc4580STejun Heoconfig NEED_PER_CPU_PAGE_FIRST_CHUNK 31211124411STejun Heo def_bool y 31311124411STejun Heo 314801e4062SJohannes Bergconfig ARCH_HIBERNATION_POSSIBLE 315801e4062SJohannes Berg def_bool y 316801e4062SJohannes Berg 317f4cb5700SJohannes Bergconfig ARCH_SUSPEND_POSSIBLE 318f4cb5700SJohannes Berg def_bool y 319f4cb5700SJohannes Berg 32053313b2cSSteve Capperconfig ARCH_WANT_GENERAL_HUGETLB 32153313b2cSSteve Capper def_bool y 32253313b2cSSteve Capper 3238d5fffb9SSam Ravnborgconfig ZONE_DMA32 324e0fd24a3SJan Beulich def_bool y if X86_64 3258d5fffb9SSam Ravnborg 3268d5fffb9SSam Ravnborgconfig AUDIT_ARCH 327e0fd24a3SJan Beulich def_bool y if X86_64 3288d5fffb9SSam Ravnborg 3296a11f75bSAkinobu Mitaconfig ARCH_SUPPORTS_DEBUG_PAGEALLOC 3306a11f75bSAkinobu Mita def_bool y 3316a11f75bSAkinobu Mita 332d6f2d75aSAndrey Ryabininconfig KASAN_SHADOW_OFFSET 333d6f2d75aSAndrey Ryabinin hex 334d6f2d75aSAndrey Ryabinin depends on KASAN 335d6f2d75aSAndrey Ryabinin default 0xdffffc0000000000 336d6f2d75aSAndrey Ryabinin 33769575d38SShane Wangconfig HAVE_INTEL_TXT 33869575d38SShane Wang def_bool y 3396ea30386SKees Cook depends on INTEL_IOMMU && ACPI 34069575d38SShane Wang 3416b0c3d44SSam Ravnborgconfig X86_32_SMP 3426b0c3d44SSam Ravnborg def_bool y 3436b0c3d44SSam Ravnborg depends on X86_32 && SMP 3446b0c3d44SSam Ravnborg 3456b0c3d44SSam Ravnborgconfig X86_64_SMP 3466b0c3d44SSam Ravnborg def_bool y 3476b0c3d44SSam Ravnborg depends on X86_64 && SMP 3486b0c3d44SSam Ravnborg 349ccbeed3aSTejun Heoconfig X86_32_LAZY_GS 350ccbeed3aSTejun Heo def_bool y 3518458f8c2SMasahiro Yamada depends on X86_32 && !STACKPROTECTOR 352ccbeed3aSTejun Heo 3532b144498SSrikar Dronamrajuconfig ARCH_SUPPORTS_UPROBES 3542b144498SSrikar Dronamraju def_bool y 3552b144498SSrikar Dronamraju 356d20642f0SRob Herringconfig FIX_EARLYCON_MEM 357d20642f0SRob Herring def_bool y 358d20642f0SRob Herring 35994d49eb3SKirill A. Shutemovconfig DYNAMIC_PHYSICAL_MASK 36094d49eb3SKirill A. Shutemov bool 36194d49eb3SKirill A. Shutemov 36298233368SKirill A. Shutemovconfig PGTABLE_LEVELS 36398233368SKirill A. Shutemov int 36477ef56e4SKirill A. Shutemov default 5 if X86_5LEVEL 36598233368SKirill A. Shutemov default 4 if X86_64 36698233368SKirill A. Shutemov default 3 if X86_PAE 36798233368SKirill A. Shutemov default 2 36898233368SKirill A. Shutemov 3692a61f474SMasahiro Yamadaconfig CC_HAS_SANE_STACKPROTECTOR 3702a61f474SMasahiro Yamada bool 3712a61f474SMasahiro Yamada default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 3722a61f474SMasahiro Yamada default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 3732a61f474SMasahiro Yamada help 3742a61f474SMasahiro Yamada We have to make sure stack protector is unconditionally disabled if 3752a61f474SMasahiro Yamada the compiler produces broken code. 3762a61f474SMasahiro Yamada 377506f1d07SSam Ravnborgmenu "Processor type and features" 378506f1d07SSam Ravnborg 3795ee71535SRandy Dunlapconfig ZONE_DMA 3805ee71535SRandy Dunlap bool "DMA memory allocation support" if EXPERT 3815ee71535SRandy Dunlap default y 3825ee71535SRandy Dunlap help 3835ee71535SRandy Dunlap DMA memory allocation support allows devices with less than 32-bit 3845ee71535SRandy Dunlap addressing to allocate within the first 16MB of address space. 3855ee71535SRandy Dunlap Disable if no such devices will be used. 3865ee71535SRandy Dunlap 3875ee71535SRandy Dunlap If unsure, say Y. 3885ee71535SRandy Dunlap 389506f1d07SSam Ravnborgconfig SMP 390506f1d07SSam Ravnborg bool "Symmetric multi-processing support" 391a7f7f624SMasahiro Yamada help 392506f1d07SSam Ravnborg This enables support for systems with more than one CPU. If you have 3934a474157SRobert Graffham a system with only one CPU, say N. If you have a system with more 3944a474157SRobert Graffham than one CPU, say Y. 395506f1d07SSam Ravnborg 3964a474157SRobert Graffham If you say N here, the kernel will run on uni- and multiprocessor 397506f1d07SSam Ravnborg machines, but will use only one CPU of a multiprocessor machine. If 398506f1d07SSam Ravnborg you say Y here, the kernel will run on many, but not all, 3994a474157SRobert Graffham uniprocessor machines. On a uniprocessor machine, the kernel 400506f1d07SSam Ravnborg will run faster if you say N here. 401506f1d07SSam Ravnborg 402506f1d07SSam Ravnborg Note that if you say Y here and choose architecture "586" or 403506f1d07SSam Ravnborg "Pentium" under "Processor family", the kernel will not work on 486 404506f1d07SSam Ravnborg architectures. Similarly, multiprocessor kernels for the "PPro" 405506f1d07SSam Ravnborg architecture may not work on all Pentium based boards. 406506f1d07SSam Ravnborg 407506f1d07SSam Ravnborg People using multiprocessor machines who say Y here should also say 408506f1d07SSam Ravnborg Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 409506f1d07SSam Ravnborg Management" code will be disabled if you say Y here. 410506f1d07SSam Ravnborg 411cb1aaebeSMauro Carvalho Chehab See also <file:Documentation/x86/i386/IO-APIC.rst>, 4124f4cfa6cSMauro Carvalho Chehab <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 413506f1d07SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 414506f1d07SSam Ravnborg 415506f1d07SSam Ravnborg If you don't know what to do here, say N. 416506f1d07SSam Ravnborg 4179def39beSJosh Triplettconfig X86_FEATURE_NAMES 4189def39beSJosh Triplett bool "Processor feature human-readable names" if EMBEDDED 4199def39beSJosh Triplett default y 420a7f7f624SMasahiro Yamada help 4219def39beSJosh Triplett This option compiles in a table of x86 feature bits and corresponding 4229def39beSJosh Triplett names. This is required to support /proc/cpuinfo and a few kernel 4239def39beSJosh Triplett messages. You can disable this to save space, at the expense of 4249def39beSJosh Triplett making those few kernel messages show numeric feature bits instead. 4259def39beSJosh Triplett 4269def39beSJosh Triplett If in doubt, say Y. 4279def39beSJosh Triplett 42806cd9a7dSYinghai Luconfig X86_X2APIC 42906cd9a7dSYinghai Lu bool "Support x2apic" 43019e3d60dSJan Kiszka depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 431a7f7f624SMasahiro Yamada help 43206cd9a7dSYinghai Lu This enables x2apic support on CPUs that have this feature. 43306cd9a7dSYinghai Lu 43406cd9a7dSYinghai Lu This allows 32-bit apic IDs (so it can support very large systems), 43506cd9a7dSYinghai Lu and accesses the local apic via MSRs not via mmio. 43606cd9a7dSYinghai Lu 43706cd9a7dSYinghai Lu If you don't know what to do here, say N. 43806cd9a7dSYinghai Lu 4396695c85bSYinghai Luconfig X86_MPPARSE 4406e87f9b7SBin Gao bool "Enable MPS table" if ACPI || SFI 4417a527688SJan Beulich default y 4425ab74722SIngo Molnar depends on X86_LOCAL_APIC 443a7f7f624SMasahiro Yamada help 4446695c85bSYinghai Lu For old smp systems that do not have proper acpi support. Newer systems 4456695c85bSYinghai Lu (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 4466695c85bSYinghai Lu 447ddd70cf9SJun Nakajimaconfig GOLDFISH 448ddd70cf9SJun Nakajima def_bool y 449ddd70cf9SJun Nakajima depends on X86_GOLDFISH 450ddd70cf9SJun Nakajima 45176b04384SDavid Woodhouseconfig RETPOLINE 45276b04384SDavid Woodhouse bool "Avoid speculative indirect branches in kernel" 45376b04384SDavid Woodhouse default y 454d5028ba8SPeter Zijlstra select STACK_VALIDATION if HAVE_STACK_VALIDATION 45576b04384SDavid Woodhouse help 45676b04384SDavid Woodhouse Compile kernel with the retpoline compiler options to guard against 45776b04384SDavid Woodhouse kernel-to-user data leaks by avoiding speculative indirect 45876b04384SDavid Woodhouse branches. Requires a compiler with -mindirect-branch=thunk-extern 45976b04384SDavid Woodhouse support for full protection. The kernel may run slower. 46076b04384SDavid Woodhouse 461e6d42931SJohannes Weinerconfig X86_CPU_RESCTRL 462e6d42931SJohannes Weiner bool "x86 CPU resource control support" 4636fe07ce3SBabu Moger depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 46459fe5a77SThomas Gleixner select KERNFS 465e79f15a4SChen Yu select PROC_CPU_RESCTRL if PROC_FS 46678e99b4aSFenghua Yu help 467e6d42931SJohannes Weiner Enable x86 CPU resource control support. 4686fe07ce3SBabu Moger 4696fe07ce3SBabu Moger Provide support for the allocation and monitoring of system resources 4706fe07ce3SBabu Moger usage by the CPU. 4716fe07ce3SBabu Moger 4726fe07ce3SBabu Moger Intel calls this Intel Resource Director Technology 4736fe07ce3SBabu Moger (Intel(R) RDT). More information about RDT can be found in the 4746fe07ce3SBabu Moger Intel x86 Architecture Software Developer Manual. 4756fe07ce3SBabu Moger 4766fe07ce3SBabu Moger AMD calls this AMD Platform Quality of Service (AMD QoS). 4776fe07ce3SBabu Moger More information about AMD QoS can be found in the AMD64 Technology 4786fe07ce3SBabu Moger Platform Quality of Service Extensions manual. 47978e99b4aSFenghua Yu 48078e99b4aSFenghua Yu Say N if unsure. 48178e99b4aSFenghua Yu 4828425091fSRavikiran G Thirumalaiif X86_32 483a0d0bb4dSRandy Dunlapconfig X86_BIGSMP 484a0d0bb4dSRandy Dunlap bool "Support for big SMP systems with more than 8 CPUs" 485a0d0bb4dSRandy Dunlap depends on SMP 486a7f7f624SMasahiro Yamada help 487e133f6eaSRandy Dunlap This option is needed for the systems that have more than 8 CPUs. 488a0d0bb4dSRandy Dunlap 489c5c606d9SRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 490c5c606d9SRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 491c5c606d9SRavikiran G Thirumalai default y 492a7f7f624SMasahiro Yamada help 49306ac8346SIngo Molnar If you disable this option then the kernel will only support 49406ac8346SIngo Molnar standard PC platforms. (which covers the vast majority of 49506ac8346SIngo Molnar systems out there.) 49606ac8346SIngo Molnar 4978425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 4988425091fSRavikiran G Thirumalai for the following (non-PC) 32 bit x86 platforms: 499cb7b8023SBen Hutchings Goldfish (Android emulator) 5008425091fSRavikiran G Thirumalai AMD Elan 5018425091fSRavikiran G Thirumalai RDC R-321x SoC 5028425091fSRavikiran G Thirumalai SGI 320/540 (Visual Workstation) 50383125a3aSAlessandro Rubini STA2X11-based (e.g. Northville) 5043f4110a4SThomas Gleixner Moorestown MID devices 50506ac8346SIngo Molnar 50606ac8346SIngo Molnar If you have one of these systems, or if you want to build a 50706ac8346SIngo Molnar generic distribution kernel, say Y here - otherwise say N. 5088425091fSRavikiran G Thirumalaiendif 50906ac8346SIngo Molnar 5108425091fSRavikiran G Thirumalaiif X86_64 5118425091fSRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 5128425091fSRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 5138425091fSRavikiran G Thirumalai default y 514a7f7f624SMasahiro Yamada help 5158425091fSRavikiran G Thirumalai If you disable this option then the kernel will only support 5168425091fSRavikiran G Thirumalai standard PC platforms. (which covers the vast majority of 5178425091fSRavikiran G Thirumalai systems out there.) 5188425091fSRavikiran G Thirumalai 5198425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5208425091fSRavikiran G Thirumalai for the following (non-PC) 64 bit x86 platforms: 52144b111b5SSteffen Persvold Numascale NumaChip 5228425091fSRavikiran G Thirumalai ScaleMP vSMP 5238425091fSRavikiran G Thirumalai SGI Ultraviolet 5248425091fSRavikiran G Thirumalai 5258425091fSRavikiran G Thirumalai If you have one of these systems, or if you want to build a 5268425091fSRavikiran G Thirumalai generic distribution kernel, say Y here - otherwise say N. 5278425091fSRavikiran G Thirumalaiendif 528c5c606d9SRavikiran G Thirumalai# This is an alphabetically sorted list of 64 bit extended platforms 529c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 53044b111b5SSteffen Persvoldconfig X86_NUMACHIP 53144b111b5SSteffen Persvold bool "Numascale NumaChip" 53244b111b5SSteffen Persvold depends on X86_64 53344b111b5SSteffen Persvold depends on X86_EXTENDED_PLATFORM 53444b111b5SSteffen Persvold depends on NUMA 53544b111b5SSteffen Persvold depends on SMP 53644b111b5SSteffen Persvold depends on X86_X2APIC 537f9726bfdSDaniel J Blueman depends on PCI_MMCONFIG 538a7f7f624SMasahiro Yamada help 53944b111b5SSteffen Persvold Adds support for Numascale NumaChip large-SMP systems. Needed to 54044b111b5SSteffen Persvold enable more than ~168 cores. 54144b111b5SSteffen Persvold If you don't have one of these, you should say N here. 54203b48632SNick Piggin 5436a48565eSIngo Molnarconfig X86_VSMP 544c5c606d9SRavikiran G Thirumalai bool "ScaleMP vSMP" 5456276a074SBorislav Petkov select HYPERVISOR_GUEST 5466a48565eSIngo Molnar select PARAVIRT 5476a48565eSIngo Molnar depends on X86_64 && PCI 548c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 549ead91d4bSShai Fultheim depends on SMP 550a7f7f624SMasahiro Yamada help 5516a48565eSIngo Molnar Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 5526a48565eSIngo Molnar supposed to run on these EM64T-based machines. Only choose this option 5536a48565eSIngo Molnar if you have one of these machines. 5546a48565eSIngo Molnar 555c5c606d9SRavikiran G Thirumalaiconfig X86_UV 556c5c606d9SRavikiran G Thirumalai bool "SGI Ultraviolet" 557c5c606d9SRavikiran G Thirumalai depends on X86_64 558c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 55954c28d29SJack Steiner depends on NUMA 5601ecb4ae5SAndrew Morton depends on EFI 5619d6c26e7SSuresh Siddha depends on X86_X2APIC 5621222e564SIngo Molnar depends on PCI 563a7f7f624SMasahiro Yamada help 564c5c606d9SRavikiran G Thirumalai This option is needed in order to support SGI Ultraviolet systems. 565c5c606d9SRavikiran G Thirumalai If you don't have one of these, you should say N here. 566c5c606d9SRavikiran G Thirumalai 567c5c606d9SRavikiran G Thirumalai# Following is an alphabetically sorted list of 32 bit extended platforms 568c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 569506f1d07SSam Ravnborg 570ddd70cf9SJun Nakajimaconfig X86_GOLDFISH 571ddd70cf9SJun Nakajima bool "Goldfish (Virtual Platform)" 572cb7b8023SBen Hutchings depends on X86_EXTENDED_PLATFORM 573a7f7f624SMasahiro Yamada help 574ddd70cf9SJun Nakajima Enable support for the Goldfish virtual platform used primarily 575ddd70cf9SJun Nakajima for Android development. Unless you are building for the Android 576ddd70cf9SJun Nakajima Goldfish emulator say N here. 577ddd70cf9SJun Nakajima 578c751e17bSThomas Gleixnerconfig X86_INTEL_CE 579c751e17bSThomas Gleixner bool "CE4100 TV platform" 580c751e17bSThomas Gleixner depends on PCI 581c751e17bSThomas Gleixner depends on PCI_GODIRECT 5826084a6e2SJiang Liu depends on X86_IO_APIC 583c751e17bSThomas Gleixner depends on X86_32 584c751e17bSThomas Gleixner depends on X86_EXTENDED_PLATFORM 58537bc9f50SDirk Brandewie select X86_REBOOTFIXUPS 586da6b737bSSebastian Andrzej Siewior select OF 587da6b737bSSebastian Andrzej Siewior select OF_EARLY_FLATTREE 588a7f7f624SMasahiro Yamada help 589c751e17bSThomas Gleixner Select for the Intel CE media processor (CE4100) SOC. 590c751e17bSThomas Gleixner This option compiles in support for the CE4100 SOC for settop 591c751e17bSThomas Gleixner boxes and media devices. 592c751e17bSThomas Gleixner 5934cb9b00fSDavid Cohenconfig X86_INTEL_MID 59443605ef1SAlan Cox bool "Intel MID platform support" 59543605ef1SAlan Cox depends on X86_EXTENDED_PLATFORM 596edc6bc78SDavid Cohen depends on X86_PLATFORM_DEVICES 5971ea7c673SAlan Cox depends on PCI 5983fda5bb4SAndy Shevchenko depends on X86_64 || (PCI_GOANY && X86_32) 5991ea7c673SAlan Cox depends on X86_IO_APIC 6007c9c3a1eSAlan Cox select SFI 6014cb9b00fSDavid Cohen select I2C 6027c9c3a1eSAlan Cox select DW_APB_TIMER 6031ea7c673SAlan Cox select APB_TIMER 60454b34aa0SMika Westerberg select INTEL_SCU_PCI 60515a713dfSMika Westerberg select MFD_INTEL_MSIC 606a7f7f624SMasahiro Yamada help 6074cb9b00fSDavid Cohen Select to build a kernel capable of supporting Intel MID (Mobile 6084cb9b00fSDavid Cohen Internet Device) platform systems which do not have the PCI legacy 6094cb9b00fSDavid Cohen interfaces. If you are building for a PC class system say N here. 6101ea7c673SAlan Cox 6114cb9b00fSDavid Cohen Intel MID platforms are based on an Intel processor and chipset which 6124cb9b00fSDavid Cohen consume less power than most of the x86 derivatives. 61343605ef1SAlan Cox 6148bbc2a13SBryan O'Donoghueconfig X86_INTEL_QUARK 6158bbc2a13SBryan O'Donoghue bool "Intel Quark platform support" 6168bbc2a13SBryan O'Donoghue depends on X86_32 6178bbc2a13SBryan O'Donoghue depends on X86_EXTENDED_PLATFORM 6188bbc2a13SBryan O'Donoghue depends on X86_PLATFORM_DEVICES 6198bbc2a13SBryan O'Donoghue depends on X86_TSC 6208bbc2a13SBryan O'Donoghue depends on PCI 6218bbc2a13SBryan O'Donoghue depends on PCI_GOANY 6228bbc2a13SBryan O'Donoghue depends on X86_IO_APIC 6238bbc2a13SBryan O'Donoghue select IOSF_MBI 6248bbc2a13SBryan O'Donoghue select INTEL_IMR 6259ab6eb51SAndy Shevchenko select COMMON_CLK 626a7f7f624SMasahiro Yamada help 6278bbc2a13SBryan O'Donoghue Select to include support for Quark X1000 SoC. 6288bbc2a13SBryan O'Donoghue Say Y here if you have a Quark based system such as the Arduino 6298bbc2a13SBryan O'Donoghue compatible Intel Galileo. 6308bbc2a13SBryan O'Donoghue 6313d48aab1SMika Westerbergconfig X86_INTEL_LPSS 6323d48aab1SMika Westerberg bool "Intel Low Power Subsystem Support" 6335962dd22SSinan Kaya depends on X86 && ACPI && PCI 6343d48aab1SMika Westerberg select COMMON_CLK 6350f531431SMathias Nyman select PINCTRL 636eebb3e8dSAndy Shevchenko select IOSF_MBI 637a7f7f624SMasahiro Yamada help 6383d48aab1SMika Westerberg Select to build support for Intel Low Power Subsystem such as 6393d48aab1SMika Westerberg found on Intel Lynxpoint PCH. Selecting this option enables 6400f531431SMathias Nyman things like clock tree (common clock framework) and pincontrol 6410f531431SMathias Nyman which are needed by the LPSS peripheral drivers. 6423d48aab1SMika Westerberg 64392082a88SKen Xueconfig X86_AMD_PLATFORM_DEVICE 64492082a88SKen Xue bool "AMD ACPI2Platform devices support" 64592082a88SKen Xue depends on ACPI 64692082a88SKen Xue select COMMON_CLK 64792082a88SKen Xue select PINCTRL 648a7f7f624SMasahiro Yamada help 64992082a88SKen Xue Select to interpret AMD specific ACPI device to platform device 65092082a88SKen Xue such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 65192082a88SKen Xue I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 65292082a88SKen Xue implemented under PINCTRL subsystem. 65392082a88SKen Xue 654ced3ce76SDavid E. Boxconfig IOSF_MBI 655ced3ce76SDavid E. Box tristate "Intel SoC IOSF Sideband support for SoC platforms" 656ced3ce76SDavid E. Box depends on PCI 657a7f7f624SMasahiro Yamada help 658ced3ce76SDavid E. Box This option enables sideband register access support for Intel SoC 659ced3ce76SDavid E. Box platforms. On these platforms the IOSF sideband is used in lieu of 660ced3ce76SDavid E. Box MSR's for some register accesses, mostly but not limited to thermal 661ced3ce76SDavid E. Box and power. Drivers may query the availability of this device to 662ced3ce76SDavid E. Box determine if they need the sideband in order to work on these 663ced3ce76SDavid E. Box platforms. The sideband is available on the following SoC products. 664ced3ce76SDavid E. Box This list is not meant to be exclusive. 665ced3ce76SDavid E. Box - BayTrail 666ced3ce76SDavid E. Box - Braswell 667ced3ce76SDavid E. Box - Quark 668ced3ce76SDavid E. Box 669ced3ce76SDavid E. Box You should say Y if you are running a kernel on one of these SoC's. 670ced3ce76SDavid E. Box 671ed2226bdSDavid E. Boxconfig IOSF_MBI_DEBUG 672ed2226bdSDavid E. Box bool "Enable IOSF sideband access through debugfs" 673ed2226bdSDavid E. Box depends on IOSF_MBI && DEBUG_FS 674a7f7f624SMasahiro Yamada help 675ed2226bdSDavid E. Box Select this option to expose the IOSF sideband access registers (MCR, 676ed2226bdSDavid E. Box MDR, MCRX) through debugfs to write and read register information from 677ed2226bdSDavid E. Box different units on the SoC. This is most useful for obtaining device 678ed2226bdSDavid E. Box state information for debug and analysis. As this is a general access 679ed2226bdSDavid E. Box mechanism, users of this option would have specific knowledge of the 680ed2226bdSDavid E. Box device they want to access. 681ed2226bdSDavid E. Box 682ed2226bdSDavid E. Box If you don't require the option or are in doubt, say N. 683ed2226bdSDavid E. Box 684c5c606d9SRavikiran G Thirumalaiconfig X86_RDC321X 685c5c606d9SRavikiran G Thirumalai bool "RDC R-321x SoC" 686506f1d07SSam Ravnborg depends on X86_32 687c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 688c5c606d9SRavikiran G Thirumalai select M486 689c5c606d9SRavikiran G Thirumalai select X86_REBOOTFIXUPS 690a7f7f624SMasahiro Yamada help 691c5c606d9SRavikiran G Thirumalai This option is needed for RDC R-321x system-on-chip, also known 692c5c606d9SRavikiran G Thirumalai as R-8610-(G). 693c5c606d9SRavikiran G Thirumalai If you don't have one of these chips, you should say N here. 694c5c606d9SRavikiran G Thirumalai 695e0c7ae37SIngo Molnarconfig X86_32_NON_STANDARD 6969c398017SIngo Molnar bool "Support non-standard 32-bit SMP architectures" 6979c398017SIngo Molnar depends on X86_32 && SMP 698c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 699a7f7f624SMasahiro Yamada help 700b5660ba7SH. Peter Anvin This option compiles in the bigsmp and STA2X11 default 701b5660ba7SH. Peter Anvin subarchitectures. It is intended for a generic binary 702b5660ba7SH. Peter Anvin kernel. If you select them all, kernel will probe it one by 703b5660ba7SH. Peter Anvin one and will fallback to default. 704d49c4288SYinghai Lu 705c5c606d9SRavikiran G Thirumalai# Alphabetically sorted list of Non standard 32 bit platforms 706d49c4288SYinghai Lu 707d949f36fSLinus Torvaldsconfig X86_SUPPORTS_MEMORY_FAILURE 7086fc108a0SJan Beulich def_bool y 709d949f36fSLinus Torvalds # MCE code calls memory_failure(): 710d949f36fSLinus Torvalds depends on X86_MCE 711d949f36fSLinus Torvalds # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 712d949f36fSLinus Torvalds # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 713d949f36fSLinus Torvalds depends on X86_64 || !SPARSEMEM 714d949f36fSLinus Torvalds select ARCH_SUPPORTS_MEMORY_FAILURE 715d949f36fSLinus Torvalds 71683125a3aSAlessandro Rubiniconfig STA2X11 71783125a3aSAlessandro Rubini bool "STA2X11 Companion Chip Support" 71883125a3aSAlessandro Rubini depends on X86_32_NON_STANDARD && PCI 71983125a3aSAlessandro Rubini select SWIOTLB 72083125a3aSAlessandro Rubini select MFD_STA2X11 7210145071bSLinus Walleij select GPIOLIB 722a7f7f624SMasahiro Yamada help 72383125a3aSAlessandro Rubini This adds support for boards based on the STA2X11 IO-Hub, 72483125a3aSAlessandro Rubini a.k.a. "ConneXt". The chip is used in place of the standard 72583125a3aSAlessandro Rubini PC chipset, so all "standard" peripherals are missing. If this 72683125a3aSAlessandro Rubini option is selected the kernel will still be able to boot on 72783125a3aSAlessandro Rubini standard PC machines. 72883125a3aSAlessandro Rubini 72982148d1dSShérabconfig X86_32_IRIS 73082148d1dSShérab tristate "Eurobraille/Iris poweroff module" 73182148d1dSShérab depends on X86_32 732a7f7f624SMasahiro Yamada help 73382148d1dSShérab The Iris machines from EuroBraille do not have APM or ACPI support 73482148d1dSShérab to shut themselves down properly. A special I/O sequence is 73582148d1dSShérab needed to do so, which is what this module does at 73682148d1dSShérab kernel shutdown. 73782148d1dSShérab 73882148d1dSShérab This is only for Iris machines from EuroBraille. 73982148d1dSShérab 74082148d1dSShérab If unused, say N. 74182148d1dSShérab 742ae1e9130SIngo Molnarconfig SCHED_OMIT_FRAME_POINTER 7433c2362e6SHarvey Harrison def_bool y 7443c2362e6SHarvey Harrison prompt "Single-depth WCHAN output" 745a87d0914SKen Chen depends on X86 746a7f7f624SMasahiro Yamada help 747506f1d07SSam Ravnborg Calculate simpler /proc/<PID>/wchan values. If this option 748506f1d07SSam Ravnborg is disabled then wchan values will recurse back to the 749506f1d07SSam Ravnborg caller function. This provides more accurate wchan values, 750506f1d07SSam Ravnborg at the expense of slightly more scheduling overhead. 751506f1d07SSam Ravnborg 752506f1d07SSam Ravnborg If in doubt, say "Y". 753506f1d07SSam Ravnborg 7546276a074SBorislav Petkovmenuconfig HYPERVISOR_GUEST 7556276a074SBorislav Petkov bool "Linux guest support" 756a7f7f624SMasahiro Yamada help 7576276a074SBorislav Petkov Say Y here to enable options for running Linux under various hyper- 7586276a074SBorislav Petkov visors. This option enables basic hypervisor detection and platform 7596276a074SBorislav Petkov setup. 760506f1d07SSam Ravnborg 7616276a074SBorislav Petkov If you say N, all options in this submenu will be skipped and 7626276a074SBorislav Petkov disabled, and Linux guest support won't be built in. 763506f1d07SSam Ravnborg 7646276a074SBorislav Petkovif HYPERVISOR_GUEST 765506f1d07SSam Ravnborg 766e61bd94aSEduardo Pereira Habkostconfig PARAVIRT 767e61bd94aSEduardo Pereira Habkost bool "Enable paravirtualization code" 768a7f7f624SMasahiro Yamada help 769e61bd94aSEduardo Pereira Habkost This changes the kernel so it can modify itself when it is run 770e61bd94aSEduardo Pereira Habkost under a hypervisor, potentially improving performance significantly 771e61bd94aSEduardo Pereira Habkost over full virtualization. However, when run without a hypervisor 772e61bd94aSEduardo Pereira Habkost the kernel is theoretically slower and slightly larger. 773e61bd94aSEduardo Pereira Habkost 774c00a280aSJuergen Grossconfig PARAVIRT_XXL 775c00a280aSJuergen Gross bool 776c00a280aSJuergen Gross 7776276a074SBorislav Petkovconfig PARAVIRT_DEBUG 7786276a074SBorislav Petkov bool "paravirt-ops debugging" 7796276a074SBorislav Petkov depends on PARAVIRT && DEBUG_KERNEL 780a7f7f624SMasahiro Yamada help 7816276a074SBorislav Petkov Enable to debug paravirt_ops internals. Specifically, BUG if 7826276a074SBorislav Petkov a paravirt_op is missing when it is called. 7836276a074SBorislav Petkov 784b4ecc126SJeremy Fitzhardingeconfig PARAVIRT_SPINLOCKS 785b4ecc126SJeremy Fitzhardinge bool "Paravirtualization layer for spinlocks" 7866ea30386SKees Cook depends on PARAVIRT && SMP 787a7f7f624SMasahiro Yamada help 788b4ecc126SJeremy Fitzhardinge Paravirtualized spinlocks allow a pvops backend to replace the 789b4ecc126SJeremy Fitzhardinge spinlock implementation with something virtualization-friendly 790b4ecc126SJeremy Fitzhardinge (for example, block the virtual CPU rather than spinning). 791b4ecc126SJeremy Fitzhardinge 7924c4e4f61SRaghavendra K T It has a minimal impact on native kernels and gives a nice performance 7934c4e4f61SRaghavendra K T benefit on paravirtualized KVM / Xen kernels. 794b4ecc126SJeremy Fitzhardinge 7954c4e4f61SRaghavendra K T If you are unsure how to answer this question, answer Y. 796b4ecc126SJeremy Fitzhardinge 797ecca2502SZhao Yakuiconfig X86_HV_CALLBACK_VECTOR 798ecca2502SZhao Yakui def_bool n 799ecca2502SZhao Yakui 8006276a074SBorislav Petkovsource "arch/x86/xen/Kconfig" 8016276a074SBorislav Petkov 8026276a074SBorislav Petkovconfig KVM_GUEST 8036276a074SBorislav Petkov bool "KVM Guest support (including kvmclock)" 8046276a074SBorislav Petkov depends on PARAVIRT 8056276a074SBorislav Petkov select PARAVIRT_CLOCK 806a1c4423bSMarcelo Tosatti select ARCH_CPUIDLE_HALTPOLL 807b1d40575SVitaly Kuznetsov select X86_HV_CALLBACK_VECTOR 8086276a074SBorislav Petkov default y 809a7f7f624SMasahiro Yamada help 8106276a074SBorislav Petkov This option enables various optimizations for running under the KVM 8116276a074SBorislav Petkov hypervisor. It includes a paravirtualized clock, so that instead 8126276a074SBorislav Petkov of relying on a PIT (or probably other) emulation by the 8136276a074SBorislav Petkov underlying device model, the host provides the guest with 8146276a074SBorislav Petkov timing infrastructure such as time of day, and system time 8156276a074SBorislav Petkov 816a1c4423bSMarcelo Tosatticonfig ARCH_CPUIDLE_HALTPOLL 817a1c4423bSMarcelo Tosatti def_bool n 818a1c4423bSMarcelo Tosatti prompt "Disable host haltpoll when loading haltpoll driver" 819a1c4423bSMarcelo Tosatti help 820a1c4423bSMarcelo Tosatti If virtualized under KVM, disable host haltpoll. 821a1c4423bSMarcelo Tosatti 8227733607fSMaran Wilsonconfig PVH 8237733607fSMaran Wilson bool "Support for running PVH guests" 824a7f7f624SMasahiro Yamada help 8257733607fSMaran Wilson This option enables the PVH entry point for guest virtual machines 8267733607fSMaran Wilson as specified in the x86/HVM direct boot ABI. 8277733607fSMaran Wilson 8286276a074SBorislav Petkovconfig PARAVIRT_TIME_ACCOUNTING 8296276a074SBorislav Petkov bool "Paravirtual steal time accounting" 8306276a074SBorislav Petkov depends on PARAVIRT 831a7f7f624SMasahiro Yamada help 8326276a074SBorislav Petkov Select this option to enable fine granularity task steal time 8336276a074SBorislav Petkov accounting. Time spent executing other tasks in parallel with 8346276a074SBorislav Petkov the current vCPU is discounted from the vCPU power. To account for 8356276a074SBorislav Petkov that, there can be a small performance impact. 8366276a074SBorislav Petkov 8376276a074SBorislav Petkov If in doubt, say N here. 8386276a074SBorislav Petkov 8397af192c9SGerd Hoffmannconfig PARAVIRT_CLOCK 8407af192c9SGerd Hoffmann bool 8417af192c9SGerd Hoffmann 8424a362601SJan Kiszkaconfig JAILHOUSE_GUEST 8434a362601SJan Kiszka bool "Jailhouse non-root cell support" 844abde587bSArnd Bergmann depends on X86_64 && PCI 84587e65d05SJan Kiszka select X86_PM_TIMER 846a7f7f624SMasahiro Yamada help 8474a362601SJan Kiszka This option allows to run Linux as guest in a Jailhouse non-root 8484a362601SJan Kiszka cell. You can leave this option disabled if you only want to start 8494a362601SJan Kiszka Jailhouse and run Linux afterwards in the root cell. 8504a362601SJan Kiszka 851ec7972c9SZhao Yakuiconfig ACRN_GUEST 852ec7972c9SZhao Yakui bool "ACRN Guest support" 853ec7972c9SZhao Yakui depends on X86_64 854498ad393SZhao Yakui select X86_HV_CALLBACK_VECTOR 855ec7972c9SZhao Yakui help 856ec7972c9SZhao Yakui This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 857ec7972c9SZhao Yakui a flexible, lightweight reference open-source hypervisor, built with 858ec7972c9SZhao Yakui real-time and safety-criticality in mind. It is built for embedded 859ec7972c9SZhao Yakui IOT with small footprint and real-time features. More details can be 860ec7972c9SZhao Yakui found in https://projectacrn.org/. 861ec7972c9SZhao Yakui 8626276a074SBorislav Petkovendif #HYPERVISOR_GUEST 86397349135SJeremy Fitzhardinge 864506f1d07SSam Ravnborgsource "arch/x86/Kconfig.cpu" 865506f1d07SSam Ravnborg 866506f1d07SSam Ravnborgconfig HPET_TIMER 8673c2362e6SHarvey Harrison def_bool X86_64 868506f1d07SSam Ravnborg prompt "HPET Timer Support" if X86_32 869a7f7f624SMasahiro Yamada help 870506f1d07SSam Ravnborg Use the IA-PC HPET (High Precision Event Timer) to manage 871506f1d07SSam Ravnborg time in preference to the PIT and RTC, if a HPET is 872506f1d07SSam Ravnborg present. 873506f1d07SSam Ravnborg HPET is the next generation timer replacing legacy 8254s. 874506f1d07SSam Ravnborg The HPET provides a stable time base on SMP 875506f1d07SSam Ravnborg systems, unlike the TSC, but it is more expensive to access, 8764e7f9df2SMichael S. Tsirkin as it is off-chip. The interface used is documented 8774e7f9df2SMichael S. Tsirkin in the HPET spec, revision 1. 878506f1d07SSam Ravnborg 879506f1d07SSam Ravnborg You can safely choose Y here. However, HPET will only be 880506f1d07SSam Ravnborg activated if the platform and the BIOS support this feature. 881506f1d07SSam Ravnborg Otherwise the 8254 will be used for timing services. 882506f1d07SSam Ravnborg 883506f1d07SSam Ravnborg Choose N to continue using the legacy 8254 timer. 884506f1d07SSam Ravnborg 885506f1d07SSam Ravnborgconfig HPET_EMULATE_RTC 8863c2362e6SHarvey Harrison def_bool y 8879d8af78bSBernhard Walle depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 888506f1d07SSam Ravnborg 889bb24c471SJacob Panconfig APB_TIMER 890933b9463SAlan Cox def_bool y if X86_INTEL_MID 891933b9463SAlan Cox prompt "Intel MID APB Timer Support" if X86_INTEL_MID 89206c3df49SJamie Iles select DW_APB_TIMER 893a0c3832aSAlan Cox depends on X86_INTEL_MID && SFI 894bb24c471SJacob Pan help 895bb24c471SJacob Pan APB timer is the replacement for 8254, HPET on X86 MID platforms. 896bb24c471SJacob Pan The APBT provides a stable time base on SMP 897bb24c471SJacob Pan systems, unlike the TSC, but it is more expensive to access, 898bb24c471SJacob Pan as it is off-chip. APB timers are always running regardless of CPU 899bb24c471SJacob Pan C states, they are used as per CPU clockevent device when possible. 900bb24c471SJacob Pan 9016a108a14SDavid Rientjes# Mark as expert because too many people got it wrong. 902506f1d07SSam Ravnborg# The code disables itself when not needed. 9037ae9392cSThomas Petazzoniconfig DMI 9047ae9392cSThomas Petazzoni default y 905cf074402SArd Biesheuvel select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 9066a108a14SDavid Rientjes bool "Enable DMI scanning" if EXPERT 907a7f7f624SMasahiro Yamada help 9087ae9392cSThomas Petazzoni Enabled scanning of DMI to identify machine quirks. Say Y 9097ae9392cSThomas Petazzoni here unless you have verified that your setup is not 9107ae9392cSThomas Petazzoni affected by entries in the DMI blacklist. Required by PNP 9117ae9392cSThomas Petazzoni BIOS code. 9127ae9392cSThomas Petazzoni 913506f1d07SSam Ravnborgconfig GART_IOMMU 91438901f1cSAndi Kleen bool "Old AMD GART IOMMU support" 9152f9237d4SChristoph Hellwig select DMA_OPS 916a4ce5a48SChristoph Hellwig select IOMMU_HELPER 917506f1d07SSam Ravnborg select SWIOTLB 91823ac4ae8SAndreas Herrmann depends on X86_64 && PCI && AMD_NB 919a7f7f624SMasahiro Yamada help 920ced3c42cSIngo Molnar Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 921ced3c42cSIngo Molnar GART based hardware IOMMUs. 922ced3c42cSIngo Molnar 923ced3c42cSIngo Molnar The GART supports full DMA access for devices with 32-bit access 924ced3c42cSIngo Molnar limitations, on systems with more than 3 GB. This is usually needed 925ced3c42cSIngo Molnar for USB, sound, many IDE/SATA chipsets and some other devices. 926ced3c42cSIngo Molnar 927ced3c42cSIngo Molnar Newer systems typically have a modern AMD IOMMU, supported via 928ced3c42cSIngo Molnar the CONFIG_AMD_IOMMU=y config option. 929ced3c42cSIngo Molnar 930ced3c42cSIngo Molnar In normal configurations this driver is only active when needed: 931ced3c42cSIngo Molnar there's more than 3 GB of memory and the system contains a 932ced3c42cSIngo Molnar 32-bit limited device. 933ced3c42cSIngo Molnar 934ced3c42cSIngo Molnar If unsure, say Y. 935506f1d07SSam Ravnborg 9361184dc2fSMike Travisconfig MAXSMP 937ddb0c5a6SSamuel Thibault bool "Enable Maximum number of SMP Processors and NUMA Nodes" 9386ea30386SKees Cook depends on X86_64 && SMP && DEBUG_KERNEL 93936f5101aSMike Travis select CPUMASK_OFFSTACK 940a7f7f624SMasahiro Yamada help 941ddb0c5a6SSamuel Thibault Enable maximum number of CPUS and NUMA Nodes for this architecture. 9421184dc2fSMike Travis If unsure, say N. 943506f1d07SSam Ravnborg 944aec6487eSIngo Molnar# 945aec6487eSIngo Molnar# The maximum number of CPUs supported: 946aec6487eSIngo Molnar# 947aec6487eSIngo Molnar# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 948aec6487eSIngo Molnar# and which can be configured interactively in the 949aec6487eSIngo Molnar# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 950aec6487eSIngo Molnar# 951aec6487eSIngo Molnar# The ranges are different on 32-bit and 64-bit kernels, depending on 952aec6487eSIngo Molnar# hardware capabilities and scalability features of the kernel. 953aec6487eSIngo Molnar# 954aec6487eSIngo Molnar# ( If MAXSMP is enabled we just use the highest possible value and disable 955aec6487eSIngo Molnar# interactive configuration. ) 956aec6487eSIngo Molnar# 957a0d0bb4dSRandy Dunlap 958aec6487eSIngo Molnarconfig NR_CPUS_RANGE_BEGIN 959a0d0bb4dSRandy Dunlap int 960aec6487eSIngo Molnar default NR_CPUS_RANGE_END if MAXSMP 961a0d0bb4dSRandy Dunlap default 1 if !SMP 962a0d0bb4dSRandy Dunlap default 2 963a0d0bb4dSRandy Dunlap 964aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 965a0d0bb4dSRandy Dunlap int 966a0d0bb4dSRandy Dunlap depends on X86_32 967aec6487eSIngo Molnar default 64 if SMP && X86_BIGSMP 968aec6487eSIngo Molnar default 8 if SMP && !X86_BIGSMP 969a0d0bb4dSRandy Dunlap default 1 if !SMP 970a0d0bb4dSRandy Dunlap 971aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 972a0d0bb4dSRandy Dunlap int 973a0d0bb4dSRandy Dunlap depends on X86_64 9741edae1aeSScott Wood default 8192 if SMP && CPUMASK_OFFSTACK 9751edae1aeSScott Wood default 512 if SMP && !CPUMASK_OFFSTACK 976a0d0bb4dSRandy Dunlap default 1 if !SMP 977aec6487eSIngo Molnar 978aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 979aec6487eSIngo Molnar int 980aec6487eSIngo Molnar depends on X86_32 981aec6487eSIngo Molnar default 32 if X86_BIGSMP 982aec6487eSIngo Molnar default 8 if SMP 983aec6487eSIngo Molnar default 1 if !SMP 984aec6487eSIngo Molnar 985aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 986aec6487eSIngo Molnar int 987aec6487eSIngo Molnar depends on X86_64 988a0d0bb4dSRandy Dunlap default 8192 if MAXSMP 989a0d0bb4dSRandy Dunlap default 64 if SMP 990aec6487eSIngo Molnar default 1 if !SMP 991a0d0bb4dSRandy Dunlap 992506f1d07SSam Ravnborgconfig NR_CPUS 99336f5101aSMike Travis int "Maximum number of CPUs" if SMP && !MAXSMP 994aec6487eSIngo Molnar range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 995aec6487eSIngo Molnar default NR_CPUS_DEFAULT 996a7f7f624SMasahiro Yamada help 997506f1d07SSam Ravnborg This allows you to specify the maximum number of CPUs which this 998bb61ccc7SJosh Boyer kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 999cad14bb9SKirill A. Shutemov supported value is 8192, otherwise the maximum value is 512. The 1000506f1d07SSam Ravnborg minimum value which makes sense is 2. 1001506f1d07SSam Ravnborg 1002aec6487eSIngo Molnar This is purely to save memory: each supported CPU adds about 8KB 1003aec6487eSIngo Molnar to the kernel image. 1004506f1d07SSam Ravnborg 1005506f1d07SSam Ravnborgconfig SCHED_SMT 1006dbe73364SThomas Gleixner def_bool y if SMP 1007506f1d07SSam Ravnborg 1008506f1d07SSam Ravnborgconfig SCHED_MC 10093c2362e6SHarvey Harrison def_bool y 10103c2362e6SHarvey Harrison prompt "Multi-core scheduler support" 1011c8e56d20SBorislav Petkov depends on SMP 1012a7f7f624SMasahiro Yamada help 1013506f1d07SSam Ravnborg Multi-core scheduler support improves the CPU scheduler's decision 1014506f1d07SSam Ravnborg making when dealing with multi-core CPU chips at a cost of slightly 1015506f1d07SSam Ravnborg increased overhead in some places. If unsure say N here. 1016506f1d07SSam Ravnborg 1017de966cf4STim Chenconfig SCHED_MC_PRIO 1018de966cf4STim Chen bool "CPU core priorities scheduler support" 10190a21fc12SIngo Molnar depends on SCHED_MC && CPU_SUP_INTEL 10200a21fc12SIngo Molnar select X86_INTEL_PSTATE 10210a21fc12SIngo Molnar select CPU_FREQ 1022de966cf4STim Chen default y 1023a7f7f624SMasahiro Yamada help 1024de966cf4STim Chen Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1025de966cf4STim Chen core ordering determined at manufacturing time, which allows 1026de966cf4STim Chen certain cores to reach higher turbo frequencies (when running 1027de966cf4STim Chen single threaded workloads) than others. 1028de966cf4STim Chen 1029de966cf4STim Chen Enabling this kernel feature teaches the scheduler about 1030de966cf4STim Chen the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1031de966cf4STim Chen scheduler's CPU selection logic accordingly, so that higher 1032de966cf4STim Chen overall system performance can be achieved. 1033de966cf4STim Chen 1034de966cf4STim Chen This feature will have no effect on CPUs without this feature. 1035de966cf4STim Chen 1036de966cf4STim Chen If unsure say Y here. 10375e76b2abSTim Chen 103830b8b006SThomas Gleixnerconfig UP_LATE_INIT 103930b8b006SThomas Gleixner def_bool y 1040ba360f88SThomas Gleixner depends on !SMP && X86_LOCAL_APIC 104130b8b006SThomas Gleixner 1042506f1d07SSam Ravnborgconfig X86_UP_APIC 104350849eefSJan Beulich bool "Local APIC support on uniprocessors" if !PCI_MSI 104450849eefSJan Beulich default PCI_MSI 104538a1dfdaSBryan O'Donoghue depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1046a7f7f624SMasahiro Yamada help 1047506f1d07SSam Ravnborg A local APIC (Advanced Programmable Interrupt Controller) is an 1048506f1d07SSam Ravnborg integrated interrupt controller in the CPU. If you have a single-CPU 1049506f1d07SSam Ravnborg system which has a processor with a local APIC, you can say Y here to 1050506f1d07SSam Ravnborg enable and use it. If you say Y here even though your machine doesn't 1051506f1d07SSam Ravnborg have a local APIC, then the kernel will still run with no slowdown at 1052506f1d07SSam Ravnborg all. The local APIC supports CPU-generated self-interrupts (timer, 1053506f1d07SSam Ravnborg performance counters), and the NMI watchdog which detects hard 1054506f1d07SSam Ravnborg lockups. 1055506f1d07SSam Ravnborg 1056506f1d07SSam Ravnborgconfig X86_UP_IOAPIC 1057506f1d07SSam Ravnborg bool "IO-APIC support on uniprocessors" 1058506f1d07SSam Ravnborg depends on X86_UP_APIC 1059a7f7f624SMasahiro Yamada help 1060506f1d07SSam Ravnborg An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1061506f1d07SSam Ravnborg SMP-capable replacement for PC-style interrupt controllers. Most 1062506f1d07SSam Ravnborg SMP systems and many recent uniprocessor systems have one. 1063506f1d07SSam Ravnborg 1064506f1d07SSam Ravnborg If you have a single-CPU system with an IO-APIC, you can say Y here 1065506f1d07SSam Ravnborg to use it. If you say Y here even though your machine doesn't have 1066506f1d07SSam Ravnborg an IO-APIC, then the kernel will still run with no slowdown at all. 1067506f1d07SSam Ravnborg 1068506f1d07SSam Ravnborgconfig X86_LOCAL_APIC 10693c2362e6SHarvey Harrison def_bool y 10700dbc6078SThomas Petazzoni depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1071b5dc8e6cSJiang Liu select IRQ_DOMAIN_HIERARCHY 107252f518a3SJiang Liu select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1073506f1d07SSam Ravnborg 1074506f1d07SSam Ravnborgconfig X86_IO_APIC 1075b1da1e71SJan Beulich def_bool y 1076b1da1e71SJan Beulich depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1077506f1d07SSam Ravnborg 107841b9eb26SStefan Assmannconfig X86_REROUTE_FOR_BROKEN_BOOT_IRQS 107941b9eb26SStefan Assmann bool "Reroute for broken boot IRQs" 108041b9eb26SStefan Assmann depends on X86_IO_APIC 1081a7f7f624SMasahiro Yamada help 108241b9eb26SStefan Assmann This option enables a workaround that fixes a source of 108341b9eb26SStefan Assmann spurious interrupts. This is recommended when threaded 108441b9eb26SStefan Assmann interrupt handling is used on systems where the generation of 108541b9eb26SStefan Assmann superfluous "boot interrupts" cannot be disabled. 108641b9eb26SStefan Assmann 108741b9eb26SStefan Assmann Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 108841b9eb26SStefan Assmann entry in the chipset's IO-APIC is masked (as, e.g. the RT 108941b9eb26SStefan Assmann kernel does during interrupt handling). On chipsets where this 109041b9eb26SStefan Assmann boot IRQ generation cannot be disabled, this workaround keeps 109141b9eb26SStefan Assmann the original IRQ line masked so that only the equivalent "boot 109241b9eb26SStefan Assmann IRQ" is delivered to the CPUs. The workaround also tells the 109341b9eb26SStefan Assmann kernel to set up the IRQ handler on the boot IRQ line. In this 109441b9eb26SStefan Assmann way only one interrupt is delivered to the kernel. Otherwise 109541b9eb26SStefan Assmann the spurious second interrupt may cause the kernel to bring 109641b9eb26SStefan Assmann down (vital) interrupt lines. 109741b9eb26SStefan Assmann 109841b9eb26SStefan Assmann Only affects "broken" chipsets. Interrupt sharing may be 109941b9eb26SStefan Assmann increased on these systems. 110041b9eb26SStefan Assmann 1101506f1d07SSam Ravnborgconfig X86_MCE 1102bab9bc65SAndi Kleen bool "Machine Check / overheating reporting" 1103648ed940SChen, Gong select GENERIC_ALLOCATOR 1104e57dbaf7SBorislav Petkov default y 1105a7f7f624SMasahiro Yamada help 1106bab9bc65SAndi Kleen Machine Check support allows the processor to notify the 1107bab9bc65SAndi Kleen kernel if it detects a problem (e.g. overheating, data corruption). 1108506f1d07SSam Ravnborg The action the kernel takes depends on the severity of the problem, 1109bab9bc65SAndi Kleen ranging from warning messages to halting the machine. 11104efc0670SAndi Kleen 11115de97c9fSTony Luckconfig X86_MCELOG_LEGACY 11125de97c9fSTony Luck bool "Support for deprecated /dev/mcelog character device" 11135de97c9fSTony Luck depends on X86_MCE 1114a7f7f624SMasahiro Yamada help 11155de97c9fSTony Luck Enable support for /dev/mcelog which is needed by the old mcelog 11165de97c9fSTony Luck userspace logging daemon. Consider switching to the new generation 11175de97c9fSTony Luck rasdaemon solution. 11185de97c9fSTony Luck 1119506f1d07SSam Ravnborgconfig X86_MCE_INTEL 11203c2362e6SHarvey Harrison def_bool y 11213c2362e6SHarvey Harrison prompt "Intel MCE features" 1122c1ebf835SAndi Kleen depends on X86_MCE && X86_LOCAL_APIC 1123a7f7f624SMasahiro Yamada help 1124506f1d07SSam Ravnborg Additional support for intel specific MCE features such as 1125506f1d07SSam Ravnborg the thermal monitor. 1126506f1d07SSam Ravnborg 1127506f1d07SSam Ravnborgconfig X86_MCE_AMD 11283c2362e6SHarvey Harrison def_bool y 11293c2362e6SHarvey Harrison prompt "AMD MCE features" 1130f5382de9SYazen Ghannam depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1131a7f7f624SMasahiro Yamada help 1132506f1d07SSam Ravnborg Additional support for AMD specific MCE features such as 1133506f1d07SSam Ravnborg the DRAM Error Threshold. 1134506f1d07SSam Ravnborg 11354efc0670SAndi Kleenconfig X86_ANCIENT_MCE 11366fc108a0SJan Beulich bool "Support for old Pentium 5 / WinChip machine checks" 1137c31d9633SAndi Kleen depends on X86_32 && X86_MCE 1138a7f7f624SMasahiro Yamada help 11394efc0670SAndi Kleen Include support for machine check handling on old Pentium 5 or WinChip 11405065a706SMasanari Iida systems. These typically need to be enabled explicitly on the command 11414efc0670SAndi Kleen line. 11424efc0670SAndi Kleen 1143b2762686SAndi Kleenconfig X86_MCE_THRESHOLD 1144b2762686SAndi Kleen depends on X86_MCE_AMD || X86_MCE_INTEL 11456fc108a0SJan Beulich def_bool y 1146b2762686SAndi Kleen 1147ea149b36SAndi Kleenconfig X86_MCE_INJECT 1148bc8e80d5SBorislav Petkov depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1149ea149b36SAndi Kleen tristate "Machine check injector support" 1150a7f7f624SMasahiro Yamada help 1151ea149b36SAndi Kleen Provide support for injecting machine checks for testing purposes. 1152ea149b36SAndi Kleen If you don't know what a machine check is and you don't do kernel 1153ea149b36SAndi Kleen QA it is safe to say n. 1154ea149b36SAndi Kleen 11554efc0670SAndi Kleenconfig X86_THERMAL_VECTOR 11564efc0670SAndi Kleen def_bool y 11575bb38adcSAndi Kleen depends on X86_MCE_INTEL 11584efc0670SAndi Kleen 115907dc900eSPeter Zijlstrasource "arch/x86/events/Kconfig" 1160e633c65aSKan Liang 11615aef51c3SAndy Lutomirskiconfig X86_LEGACY_VM86 11621e642812SIngo Molnar bool "Legacy VM86 support" 1163506f1d07SSam Ravnborg depends on X86_32 1164a7f7f624SMasahiro Yamada help 11655aef51c3SAndy Lutomirski This option allows user programs to put the CPU into V8086 11665aef51c3SAndy Lutomirski mode, which is an 80286-era approximation of 16-bit real mode. 11675aef51c3SAndy Lutomirski 11685aef51c3SAndy Lutomirski Some very old versions of X and/or vbetool require this option 11695aef51c3SAndy Lutomirski for user mode setting. Similarly, DOSEMU will use it if 11705aef51c3SAndy Lutomirski available to accelerate real mode DOS programs. However, any 11715aef51c3SAndy Lutomirski recent version of DOSEMU, X, or vbetool should be fully 11725aef51c3SAndy Lutomirski functional even without kernel VM86 support, as they will all 11731e642812SIngo Molnar fall back to software emulation. Nevertheless, if you are using 11741e642812SIngo Molnar a 16-bit DOS program where 16-bit performance matters, vm86 11751e642812SIngo Molnar mode might be faster than emulation and you might want to 11761e642812SIngo Molnar enable this option. 11775aef51c3SAndy Lutomirski 11781e642812SIngo Molnar Note that any app that works on a 64-bit kernel is unlikely to 11791e642812SIngo Molnar need this option, as 64-bit kernels don't, and can't, support 11801e642812SIngo Molnar V8086 mode. This option is also unrelated to 16-bit protected 11811e642812SIngo Molnar mode and is not needed to run most 16-bit programs under Wine. 11825aef51c3SAndy Lutomirski 11831e642812SIngo Molnar Enabling this option increases the complexity of the kernel 11841e642812SIngo Molnar and slows down exception handling a tiny bit. 11855aef51c3SAndy Lutomirski 11861e642812SIngo Molnar If unsure, say N here. 11875aef51c3SAndy Lutomirski 11885aef51c3SAndy Lutomirskiconfig VM86 11895aef51c3SAndy Lutomirski bool 11905aef51c3SAndy Lutomirski default X86_LEGACY_VM86 119134273f41SH. Peter Anvin 119234273f41SH. Peter Anvinconfig X86_16BIT 119334273f41SH. Peter Anvin bool "Enable support for 16-bit segments" if EXPERT 119434273f41SH. Peter Anvin default y 1195a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 1196a7f7f624SMasahiro Yamada help 119734273f41SH. Peter Anvin This option is required by programs like Wine to run 16-bit 119834273f41SH. Peter Anvin protected mode legacy code on x86 processors. Disabling 119934273f41SH. Peter Anvin this option saves about 300 bytes on i386, or around 6K text 120034273f41SH. Peter Anvin plus 16K runtime memory on x86-64, 120134273f41SH. Peter Anvin 120234273f41SH. Peter Anvinconfig X86_ESPFIX32 120334273f41SH. Peter Anvin def_bool y 120434273f41SH. Peter Anvin depends on X86_16BIT && X86_32 1205506f1d07SSam Ravnborg 1206197725deSH. Peter Anvinconfig X86_ESPFIX64 1207197725deSH. Peter Anvin def_bool y 120834273f41SH. Peter Anvin depends on X86_16BIT && X86_64 1209506f1d07SSam Ravnborg 12101ad83c85SAndy Lutomirskiconfig X86_VSYSCALL_EMULATION 12111ad83c85SAndy Lutomirski bool "Enable vsyscall emulation" if EXPERT 12121ad83c85SAndy Lutomirski default y 12131ad83c85SAndy Lutomirski depends on X86_64 1214a7f7f624SMasahiro Yamada help 12151ad83c85SAndy Lutomirski This enables emulation of the legacy vsyscall page. Disabling 12161ad83c85SAndy Lutomirski it is roughly equivalent to booting with vsyscall=none, except 12171ad83c85SAndy Lutomirski that it will also disable the helpful warning if a program 12181ad83c85SAndy Lutomirski tries to use a vsyscall. With this option set to N, offending 12191ad83c85SAndy Lutomirski programs will just segfault, citing addresses of the form 12201ad83c85SAndy Lutomirski 0xffffffffff600?00. 12211ad83c85SAndy Lutomirski 12221ad83c85SAndy Lutomirski This option is required by many programs built before 2013, and 12231ad83c85SAndy Lutomirski care should be used even with newer programs if set to N. 12241ad83c85SAndy Lutomirski 12251ad83c85SAndy Lutomirski Disabling this option saves about 7K of kernel size and 12261ad83c85SAndy Lutomirski possibly 4K of additional runtime pagetable memory. 12271ad83c85SAndy Lutomirski 1228111e7b15SThomas Gleixnerconfig X86_IOPL_IOPERM 1229111e7b15SThomas Gleixner bool "IOPERM and IOPL Emulation" 1230a24ca997SThomas Gleixner default y 1231a7f7f624SMasahiro Yamada help 1232111e7b15SThomas Gleixner This enables the ioperm() and iopl() syscalls which are necessary 1233111e7b15SThomas Gleixner for legacy applications. 1234111e7b15SThomas Gleixner 1235c8137aceSThomas Gleixner Legacy IOPL support is an overbroad mechanism which allows user 1236c8137aceSThomas Gleixner space aside of accessing all 65536 I/O ports also to disable 1237c8137aceSThomas Gleixner interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1238c8137aceSThomas Gleixner capabilities and permission from potentially active security 1239c8137aceSThomas Gleixner modules. 1240c8137aceSThomas Gleixner 1241c8137aceSThomas Gleixner The emulation restricts the functionality of the syscall to 1242c8137aceSThomas Gleixner only allowing the full range I/O port access, but prevents the 1243a24ca997SThomas Gleixner ability to disable interrupts from user space which would be 1244a24ca997SThomas Gleixner granted if the hardware IOPL mechanism would be used. 1245c8137aceSThomas Gleixner 1246506f1d07SSam Ravnborgconfig TOSHIBA 1247506f1d07SSam Ravnborg tristate "Toshiba Laptop support" 1248506f1d07SSam Ravnborg depends on X86_32 1249a7f7f624SMasahiro Yamada help 1250506f1d07SSam Ravnborg This adds a driver to safely access the System Management Mode of 1251506f1d07SSam Ravnborg the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1252506f1d07SSam Ravnborg not work on models with a Phoenix BIOS. The System Management Mode 1253506f1d07SSam Ravnborg is used to set the BIOS and power saving options on Toshiba portables. 1254506f1d07SSam Ravnborg 1255506f1d07SSam Ravnborg For information on utilities to make use of this driver see the 1256506f1d07SSam Ravnborg Toshiba Linux utilities web site at: 1257506f1d07SSam Ravnborg <http://www.buzzard.org.uk/toshiba/>. 1258506f1d07SSam Ravnborg 1259506f1d07SSam Ravnborg Say Y if you intend to run this kernel on a Toshiba portable. 1260506f1d07SSam Ravnborg Say N otherwise. 1261506f1d07SSam Ravnborg 1262506f1d07SSam Ravnborgconfig I8K 1263039ae585SPali Rohár tristate "Dell i8k legacy laptop support" 1264949a9d70SJean Delvare select HWMON 1265039ae585SPali Rohár select SENSORS_DELL_SMM 1266a7f7f624SMasahiro Yamada help 1267039ae585SPali Rohár This option enables legacy /proc/i8k userspace interface in hwmon 1268039ae585SPali Rohár dell-smm-hwmon driver. Character file /proc/i8k reports bios version, 1269039ae585SPali Rohár temperature and allows controlling fan speeds of Dell laptops via 1270039ae585SPali Rohár System Management Mode. For old Dell laptops (like Dell Inspiron 8000) 1271039ae585SPali Rohár it reports also power and hotkey status. For fan speed control is 1272039ae585SPali Rohár needed userspace package i8kutils. 1273506f1d07SSam Ravnborg 1274039ae585SPali Rohár Say Y if you intend to run this kernel on old Dell laptops or want to 1275039ae585SPali Rohár use userspace package i8kutils. 1276506f1d07SSam Ravnborg Say N otherwise. 1277506f1d07SSam Ravnborg 1278506f1d07SSam Ravnborgconfig X86_REBOOTFIXUPS 12799ba16087SJan Beulich bool "Enable X86 board specific fixups for reboot" 12809ba16087SJan Beulich depends on X86_32 1281a7f7f624SMasahiro Yamada help 1282506f1d07SSam Ravnborg This enables chipset and/or board specific fixups to be done 1283506f1d07SSam Ravnborg in order to get reboot to work correctly. This is only needed on 1284506f1d07SSam Ravnborg some combinations of hardware and BIOS. The symptom, for which 1285506f1d07SSam Ravnborg this config is intended, is when reboot ends with a stalled/hung 1286506f1d07SSam Ravnborg system. 1287506f1d07SSam Ravnborg 1288506f1d07SSam Ravnborg Currently, the only fixup is for the Geode machines using 12895e3a77e9SFlorian Fainelli CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1290506f1d07SSam Ravnborg 1291506f1d07SSam Ravnborg Say Y if you want to enable the fixup. Currently, it's safe to 1292506f1d07SSam Ravnborg enable this option even if you don't need it. 1293506f1d07SSam Ravnborg Say N otherwise. 1294506f1d07SSam Ravnborg 1295506f1d07SSam Ravnborgconfig MICROCODE 12969a2bc335SBorislav Petkov bool "CPU microcode loading support" 12979a2bc335SBorislav Petkov default y 129880030e3dSBorislav Petkov depends on CPU_SUP_AMD || CPU_SUP_INTEL 1299a7f7f624SMasahiro Yamada help 1300506f1d07SSam Ravnborg If you say Y here, you will be able to update the microcode on 13015f9c01aaSBorislav Petkov Intel and AMD processors. The Intel support is for the IA32 family, 13025f9c01aaSBorislav Petkov e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 13035f9c01aaSBorislav Petkov AMD support is for families 0x10 and later. You will obviously need 13045f9c01aaSBorislav Petkov the actual microcode binary data itself which is not shipped with 13055f9c01aaSBorislav Petkov the Linux kernel. 1306506f1d07SSam Ravnborg 13075f9c01aaSBorislav Petkov The preferred method to load microcode from a detached initrd is described 1308cb1aaebeSMauro Carvalho Chehab in Documentation/x86/microcode.rst. For that you need to enable 13095f9c01aaSBorislav Petkov CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 13105f9c01aaSBorislav Petkov initrd for microcode blobs. 1311506f1d07SSam Ravnborg 1312c508c46eSBenjamin Gilbert In addition, you can build the microcode into the kernel. For that you 1313c508c46eSBenjamin Gilbert need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1314c508c46eSBenjamin Gilbert config option. 1315506f1d07SSam Ravnborg 13168d86f390SPeter Orubaconfig MICROCODE_INTEL 1317e43f6e67SBorislav Petkov bool "Intel microcode loading support" 13188d86f390SPeter Oruba depends on MICROCODE 13198d86f390SPeter Oruba default MICROCODE 1320a7f7f624SMasahiro Yamada help 13218d86f390SPeter Oruba This options enables microcode patch loading support for Intel 13228d86f390SPeter Oruba processors. 13238d86f390SPeter Oruba 1324b8989db9SAlan For the current Intel microcode data package go to 1325b8989db9SAlan <https://downloadcenter.intel.com> and search for 1326b8989db9SAlan 'Linux Processor Microcode Data File'. 13278d86f390SPeter Oruba 132880cc9f10SPeter Orubaconfig MICROCODE_AMD 1329e43f6e67SBorislav Petkov bool "AMD microcode loading support" 133080cc9f10SPeter Oruba depends on MICROCODE 1331a7f7f624SMasahiro Yamada help 133280cc9f10SPeter Oruba If you select this option, microcode patch loading support for AMD 133380cc9f10SPeter Oruba processors will be enabled. 133480cc9f10SPeter Oruba 1335506f1d07SSam Ravnborgconfig MICROCODE_OLD_INTERFACE 1336c02f48e0SBorislav Petkov bool "Ancient loading interface (DEPRECATED)" 1337c02f48e0SBorislav Petkov default n 1338506f1d07SSam Ravnborg depends on MICROCODE 1339a7f7f624SMasahiro Yamada help 1340c02f48e0SBorislav Petkov DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1341c02f48e0SBorislav Petkov which was used by userspace tools like iucode_tool and microcode.ctl. 1342c02f48e0SBorislav Petkov It is inadequate because it runs too late to be able to properly 1343c02f48e0SBorislav Petkov load microcode on a machine and it needs special tools. Instead, you 1344c02f48e0SBorislav Petkov should've switched to the early loading method with the initrd or 1345cb1aaebeSMauro Carvalho Chehab builtin microcode by now: Documentation/x86/microcode.rst 1346506f1d07SSam Ravnborg 1347506f1d07SSam Ravnborgconfig X86_MSR 1348506f1d07SSam Ravnborg tristate "/dev/cpu/*/msr - Model-specific register support" 1349a7f7f624SMasahiro Yamada help 1350506f1d07SSam Ravnborg This device gives privileged processes access to the x86 1351506f1d07SSam Ravnborg Model-Specific Registers (MSRs). It is a character device with 1352506f1d07SSam Ravnborg major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1353506f1d07SSam Ravnborg MSR accesses are directed to a specific CPU on multi-processor 1354506f1d07SSam Ravnborg systems. 1355506f1d07SSam Ravnborg 1356506f1d07SSam Ravnborgconfig X86_CPUID 1357506f1d07SSam Ravnborg tristate "/dev/cpu/*/cpuid - CPU information support" 1358a7f7f624SMasahiro Yamada help 1359506f1d07SSam Ravnborg This device gives processes access to the x86 CPUID instruction to 1360506f1d07SSam Ravnborg be executed on a specific processor. It is a character device 1361506f1d07SSam Ravnborg with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1362506f1d07SSam Ravnborg /dev/cpu/31/cpuid. 1363506f1d07SSam Ravnborg 1364506f1d07SSam Ravnborgchoice 1365506f1d07SSam Ravnborg prompt "High Memory Support" 13666fc108a0SJan Beulich default HIGHMEM4G 1367506f1d07SSam Ravnborg depends on X86_32 1368506f1d07SSam Ravnborg 1369506f1d07SSam Ravnborgconfig NOHIGHMEM 1370506f1d07SSam Ravnborg bool "off" 1371a7f7f624SMasahiro Yamada help 1372506f1d07SSam Ravnborg Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1373506f1d07SSam Ravnborg However, the address space of 32-bit x86 processors is only 4 1374506f1d07SSam Ravnborg Gigabytes large. That means that, if you have a large amount of 1375506f1d07SSam Ravnborg physical memory, not all of it can be "permanently mapped" by the 1376506f1d07SSam Ravnborg kernel. The physical memory that's not permanently mapped is called 1377506f1d07SSam Ravnborg "high memory". 1378506f1d07SSam Ravnborg 1379506f1d07SSam Ravnborg If you are compiling a kernel which will never run on a machine with 1380506f1d07SSam Ravnborg more than 1 Gigabyte total physical RAM, answer "off" here (default 1381506f1d07SSam Ravnborg choice and suitable for most users). This will result in a "3GB/1GB" 1382506f1d07SSam Ravnborg split: 3GB are mapped so that each process sees a 3GB virtual memory 1383506f1d07SSam Ravnborg space and the remaining part of the 4GB virtual memory space is used 1384506f1d07SSam Ravnborg by the kernel to permanently map as much physical memory as 1385506f1d07SSam Ravnborg possible. 1386506f1d07SSam Ravnborg 1387506f1d07SSam Ravnborg If the machine has between 1 and 4 Gigabytes physical RAM, then 1388506f1d07SSam Ravnborg answer "4GB" here. 1389506f1d07SSam Ravnborg 1390506f1d07SSam Ravnborg If more than 4 Gigabytes is used then answer "64GB" here. This 1391506f1d07SSam Ravnborg selection turns Intel PAE (Physical Address Extension) mode on. 1392506f1d07SSam Ravnborg PAE implements 3-level paging on IA32 processors. PAE is fully 1393506f1d07SSam Ravnborg supported by Linux, PAE mode is implemented on all recent Intel 1394506f1d07SSam Ravnborg processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1395506f1d07SSam Ravnborg then the kernel will not boot on CPUs that don't support PAE! 1396506f1d07SSam Ravnborg 1397506f1d07SSam Ravnborg The actual amount of total physical memory will either be 1398506f1d07SSam Ravnborg auto detected or can be forced by using a kernel command line option 1399506f1d07SSam Ravnborg such as "mem=256M". (Try "man bootparam" or see the documentation of 1400506f1d07SSam Ravnborg your boot loader (lilo or loadlin) about how to pass options to the 1401506f1d07SSam Ravnborg kernel at boot time.) 1402506f1d07SSam Ravnborg 1403506f1d07SSam Ravnborg If unsure, say "off". 1404506f1d07SSam Ravnborg 1405506f1d07SSam Ravnborgconfig HIGHMEM4G 1406506f1d07SSam Ravnborg bool "4GB" 1407a7f7f624SMasahiro Yamada help 1408506f1d07SSam Ravnborg Select this if you have a 32-bit processor and between 1 and 4 1409506f1d07SSam Ravnborg gigabytes of physical RAM. 1410506f1d07SSam Ravnborg 1411506f1d07SSam Ravnborgconfig HIGHMEM64G 1412506f1d07SSam Ravnborg bool "64GB" 141369b8d3fcSMatthew Whitehead depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6 1414506f1d07SSam Ravnborg select X86_PAE 1415a7f7f624SMasahiro Yamada help 1416506f1d07SSam Ravnborg Select this if you have a 32-bit processor and more than 4 1417506f1d07SSam Ravnborg gigabytes of physical RAM. 1418506f1d07SSam Ravnborg 1419506f1d07SSam Ravnborgendchoice 1420506f1d07SSam Ravnborg 1421506f1d07SSam Ravnborgchoice 14226a108a14SDavid Rientjes prompt "Memory split" if EXPERT 1423506f1d07SSam Ravnborg default VMSPLIT_3G 1424506f1d07SSam Ravnborg depends on X86_32 1425a7f7f624SMasahiro Yamada help 1426506f1d07SSam Ravnborg Select the desired split between kernel and user memory. 1427506f1d07SSam Ravnborg 1428506f1d07SSam Ravnborg If the address range available to the kernel is less than the 1429506f1d07SSam Ravnborg physical memory installed, the remaining memory will be available 1430506f1d07SSam Ravnborg as "high memory". Accessing high memory is a little more costly 1431506f1d07SSam Ravnborg than low memory, as it needs to be mapped into the kernel first. 1432506f1d07SSam Ravnborg Note that increasing the kernel address space limits the range 1433506f1d07SSam Ravnborg available to user programs, making the address space there 1434506f1d07SSam Ravnborg tighter. Selecting anything other than the default 3G/1G split 1435506f1d07SSam Ravnborg will also likely make your kernel incompatible with binary-only 1436506f1d07SSam Ravnborg kernel modules. 1437506f1d07SSam Ravnborg 1438506f1d07SSam Ravnborg If you are not absolutely sure what you are doing, leave this 1439506f1d07SSam Ravnborg option alone! 1440506f1d07SSam Ravnborg 1441506f1d07SSam Ravnborg config VMSPLIT_3G 1442506f1d07SSam Ravnborg bool "3G/1G user/kernel split" 1443506f1d07SSam Ravnborg config VMSPLIT_3G_OPT 1444506f1d07SSam Ravnborg depends on !X86_PAE 1445506f1d07SSam Ravnborg bool "3G/1G user/kernel split (for full 1G low memory)" 1446506f1d07SSam Ravnborg config VMSPLIT_2G 1447506f1d07SSam Ravnborg bool "2G/2G user/kernel split" 1448506f1d07SSam Ravnborg config VMSPLIT_2G_OPT 1449506f1d07SSam Ravnborg depends on !X86_PAE 1450506f1d07SSam Ravnborg bool "2G/2G user/kernel split (for full 2G low memory)" 1451506f1d07SSam Ravnborg config VMSPLIT_1G 1452506f1d07SSam Ravnborg bool "1G/3G user/kernel split" 1453506f1d07SSam Ravnborgendchoice 1454506f1d07SSam Ravnborg 1455506f1d07SSam Ravnborgconfig PAGE_OFFSET 1456506f1d07SSam Ravnborg hex 1457506f1d07SSam Ravnborg default 0xB0000000 if VMSPLIT_3G_OPT 1458506f1d07SSam Ravnborg default 0x80000000 if VMSPLIT_2G 1459506f1d07SSam Ravnborg default 0x78000000 if VMSPLIT_2G_OPT 1460506f1d07SSam Ravnborg default 0x40000000 if VMSPLIT_1G 1461506f1d07SSam Ravnborg default 0xC0000000 1462506f1d07SSam Ravnborg depends on X86_32 1463506f1d07SSam Ravnborg 1464506f1d07SSam Ravnborgconfig HIGHMEM 14653c2362e6SHarvey Harrison def_bool y 1466506f1d07SSam Ravnborg depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1467506f1d07SSam Ravnborg 1468506f1d07SSam Ravnborgconfig X86_PAE 14699ba16087SJan Beulich bool "PAE (Physical Address Extension) Support" 1470506f1d07SSam Ravnborg depends on X86_32 && !HIGHMEM4G 1471d4a451d5SChristoph Hellwig select PHYS_ADDR_T_64BIT 14729d99c712SChristian Melki select SWIOTLB 1473a7f7f624SMasahiro Yamada help 1474506f1d07SSam Ravnborg PAE is required for NX support, and furthermore enables 1475506f1d07SSam Ravnborg larger swapspace support for non-overcommit purposes. It 1476506f1d07SSam Ravnborg has the cost of more pagetable lookup overhead, and also 1477506f1d07SSam Ravnborg consumes more pagetable space per process. 1478506f1d07SSam Ravnborg 147977ef56e4SKirill A. Shutemovconfig X86_5LEVEL 148077ef56e4SKirill A. Shutemov bool "Enable 5-level page tables support" 148118ec1eafSKirill A. Shutemov default y 1482eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 1483162434e7SKirill A. Shutemov select SPARSEMEM_VMEMMAP 148477ef56e4SKirill A. Shutemov depends on X86_64 1485a7f7f624SMasahiro Yamada help 148677ef56e4SKirill A. Shutemov 5-level paging enables access to larger address space: 148777ef56e4SKirill A. Shutemov upto 128 PiB of virtual address space and 4 PiB of 148877ef56e4SKirill A. Shutemov physical address space. 148977ef56e4SKirill A. Shutemov 149077ef56e4SKirill A. Shutemov It will be supported by future Intel CPUs. 149177ef56e4SKirill A. Shutemov 14926657fca0SKirill A. Shutemov A kernel with the option enabled can be booted on machines that 14936657fca0SKirill A. Shutemov support 4- or 5-level paging. 149477ef56e4SKirill A. Shutemov 1495cb1aaebeSMauro Carvalho Chehab See Documentation/x86/x86_64/5level-paging.rst for more 149677ef56e4SKirill A. Shutemov information. 149777ef56e4SKirill A. Shutemov 149877ef56e4SKirill A. Shutemov Say N if unsure. 149977ef56e4SKirill A. Shutemov 150010971ab2SIngo Molnarconfig X86_DIRECT_GBPAGES 1501e5008abeSLuis R. Rodriguez def_bool y 15022e1da13fSVlastimil Babka depends on X86_64 1503a7f7f624SMasahiro Yamada help 150410971ab2SIngo Molnar Certain kernel features effectively disable kernel 150510971ab2SIngo Molnar linear 1 GB mappings (even if the CPU otherwise 150610971ab2SIngo Molnar supports them), so don't confuse the user by printing 150710971ab2SIngo Molnar that we have them enabled. 15089e899816SNick Piggin 15095c280cf6SThomas Gleixnerconfig X86_CPA_STATISTICS 15105c280cf6SThomas Gleixner bool "Enable statistic for Change Page Attribute" 15115c280cf6SThomas Gleixner depends on DEBUG_FS 1512a7f7f624SMasahiro Yamada help 1513b75baaf3SIngo Molnar Expose statistics about the Change Page Attribute mechanism, which 1514a943245aSColin Ian King helps to determine the effectiveness of preserving large and huge 15155c280cf6SThomas Gleixner page mappings when mapping protections are changed. 15165c280cf6SThomas Gleixner 15177744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT 15187744ccdbSTom Lendacky bool "AMD Secure Memory Encryption (SME) support" 15197744ccdbSTom Lendacky depends on X86_64 && CPU_SUP_AMD 152082fef0adSDavid Rientjes select DMA_COHERENT_POOL 152194d49eb3SKirill A. Shutemov select DYNAMIC_PHYSICAL_MASK 1522ce9084baSArd Biesheuvel select ARCH_USE_MEMREMAP_PROT 15239087c375STom Lendacky select ARCH_HAS_FORCE_DMA_UNENCRYPTED 1524*597cfe48SJoerg Roedel select INSTRUCTION_DECODER 1525a7f7f624SMasahiro Yamada help 15267744ccdbSTom Lendacky Say yes to enable support for the encryption of system memory. 15277744ccdbSTom Lendacky This requires an AMD processor that supports Secure Memory 15287744ccdbSTom Lendacky Encryption (SME). 15297744ccdbSTom Lendacky 15307744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 15317744ccdbSTom Lendacky bool "Activate AMD Secure Memory Encryption (SME) by default" 15327744ccdbSTom Lendacky default y 15337744ccdbSTom Lendacky depends on AMD_MEM_ENCRYPT 1534a7f7f624SMasahiro Yamada help 15357744ccdbSTom Lendacky Say yes to have system memory encrypted by default if running on 15367744ccdbSTom Lendacky an AMD processor that supports Secure Memory Encryption (SME). 15377744ccdbSTom Lendacky 15387744ccdbSTom Lendacky If set to Y, then the encryption of system memory can be 15397744ccdbSTom Lendacky deactivated with the mem_encrypt=off command line option. 15407744ccdbSTom Lendacky 15417744ccdbSTom Lendacky If set to N, then the encryption of system memory can be 15427744ccdbSTom Lendacky activated with the mem_encrypt=on command line option. 15437744ccdbSTom Lendacky 1544506f1d07SSam Ravnborg# Common NUMA Features 1545506f1d07SSam Ravnborgconfig NUMA 1546e133f6eaSRandy Dunlap bool "NUMA Memory Allocation and Scheduler Support" 1547506f1d07SSam Ravnborg depends on SMP 1548b5660ba7SH. Peter Anvin depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1549b5660ba7SH. Peter Anvin default y if X86_BIGSMP 1550a7f7f624SMasahiro Yamada help 1551e133f6eaSRandy Dunlap Enable NUMA (Non-Uniform Memory Access) support. 1552fd51b2d7SKOSAKI Motohiro 1553506f1d07SSam Ravnborg The kernel will try to allocate memory used by a CPU on the 1554506f1d07SSam Ravnborg local memory controller of the CPU and add some more 1555506f1d07SSam Ravnborg NUMA awareness to the kernel. 1556506f1d07SSam Ravnborg 1557c280ea5eSIngo Molnar For 64-bit this is recommended if the system is Intel Core i7 1558fd51b2d7SKOSAKI Motohiro (or later), AMD Opteron, or EM64T NUMA. 1559fd51b2d7SKOSAKI Motohiro 1560b5660ba7SH. Peter Anvin For 32-bit this is only needed if you boot a 32-bit 15617cf6c945SDavid Rientjes kernel on a 64-bit NUMA platform. 1562fd51b2d7SKOSAKI Motohiro 1563fd51b2d7SKOSAKI Motohiro Otherwise, you should say N. 1564506f1d07SSam Ravnborg 1565eec1d4faSHans Rosenfeldconfig AMD_NUMA 15663c2362e6SHarvey Harrison def_bool y 15673c2362e6SHarvey Harrison prompt "Old style AMD Opteron NUMA detection" 15685da0ef9aSTejun Heo depends on X86_64 && NUMA && PCI 1569a7f7f624SMasahiro Yamada help 1570eec1d4faSHans Rosenfeld Enable AMD NUMA node topology detection. You should say Y here if 1571eec1d4faSHans Rosenfeld you have a multi processor AMD system. This uses an old method to 1572eec1d4faSHans Rosenfeld read the NUMA configuration directly from the builtin Northbridge 1573eec1d4faSHans Rosenfeld of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1574eec1d4faSHans Rosenfeld which also takes priority if both are compiled in. 1575506f1d07SSam Ravnborg 1576506f1d07SSam Ravnborgconfig X86_64_ACPI_NUMA 15773c2362e6SHarvey Harrison def_bool y 15783c2362e6SHarvey Harrison prompt "ACPI NUMA detection" 1579506f1d07SSam Ravnborg depends on X86_64 && NUMA && ACPI && PCI 1580506f1d07SSam Ravnborg select ACPI_NUMA 1581a7f7f624SMasahiro Yamada help 1582506f1d07SSam Ravnborg Enable ACPI SRAT based node topology detection. 1583506f1d07SSam Ravnborg 1584506f1d07SSam Ravnborgconfig NUMA_EMU 1585506f1d07SSam Ravnborg bool "NUMA emulation" 15861b7e03efSTejun Heo depends on NUMA 1587a7f7f624SMasahiro Yamada help 1588506f1d07SSam Ravnborg Enable NUMA emulation. A flat machine will be split 1589506f1d07SSam Ravnborg into virtual nodes when booted with "numa=fake=N", where N is the 1590506f1d07SSam Ravnborg number of nodes. This is only useful for debugging. 1591506f1d07SSam Ravnborg 1592506f1d07SSam Ravnborgconfig NODES_SHIFT 1593d25e26b6SLinus Torvalds int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 159451591e31SDavid Rientjes range 1 10 159551591e31SDavid Rientjes default "10" if MAXSMP 1596506f1d07SSam Ravnborg default "6" if X86_64 1597506f1d07SSam Ravnborg default "3" 1598506f1d07SSam Ravnborg depends on NEED_MULTIPLE_NODES 1599a7f7f624SMasahiro Yamada help 16001184dc2fSMike Travis Specify the maximum number of NUMA Nodes available on the target 1601692105b8SMatt LaPlante system. Increases memory reserved to accommodate various tables. 1602506f1d07SSam Ravnborg 1603506f1d07SSam Ravnborgconfig ARCH_FLATMEM_ENABLE 1604506f1d07SSam Ravnborg def_bool y 16053b16651fSTejun Heo depends on X86_32 && !NUMA 1606506f1d07SSam Ravnborg 1607506f1d07SSam Ravnborgconfig ARCH_SPARSEMEM_ENABLE 1608506f1d07SSam Ravnborg def_bool y 16096ea30386SKees Cook depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1610506f1d07SSam Ravnborg select SPARSEMEM_STATIC if X86_32 1611506f1d07SSam Ravnborg select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1612506f1d07SSam Ravnborg 16133b16651fSTejun Heoconfig ARCH_SPARSEMEM_DEFAULT 16146ad57f7fSMike Rapoport def_bool X86_64 || (NUMA && X86_32) 16153b16651fSTejun Heo 1616506f1d07SSam Ravnborgconfig ARCH_SELECT_MEMORY_MODEL 1617506f1d07SSam Ravnborg def_bool y 1618b263295dSChristoph Lameter depends on ARCH_SPARSEMEM_ENABLE 1619506f1d07SSam Ravnborg 1620506f1d07SSam Ravnborgconfig ARCH_MEMORY_PROBE 1621a0842b70SToshi Kani bool "Enable sysfs memory/probe interface" 16223120e25eSJan Beulich depends on X86_64 && MEMORY_HOTPLUG 1623a0842b70SToshi Kani help 1624a0842b70SToshi Kani This option enables a sysfs memory/probe interface for testing. 1625cb1aaebeSMauro Carvalho Chehab See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1626a0842b70SToshi Kani If you are unsure how to answer this question, answer N. 1627506f1d07SSam Ravnborg 16283b16651fSTejun Heoconfig ARCH_PROC_KCORE_TEXT 16293b16651fSTejun Heo def_bool y 16303b16651fSTejun Heo depends on X86_64 && PROC_KCORE 16313b16651fSTejun Heo 1632a29815a3SAvi Kivityconfig ILLEGAL_POINTER_VALUE 1633a29815a3SAvi Kivity hex 1634a29815a3SAvi Kivity default 0 if X86_32 1635a29815a3SAvi Kivity default 0xdead000000000000 if X86_64 1636a29815a3SAvi Kivity 16377a67832cSDan Williamsconfig X86_PMEM_LEGACY_DEVICE 16387a67832cSDan Williams bool 16397a67832cSDan Williams 1640ec776ef6SChristoph Hellwigconfig X86_PMEM_LEGACY 16417a67832cSDan Williams tristate "Support non-standard NVDIMMs and ADR protected memory" 16429f53f9faSDan Williams depends on PHYS_ADDR_T_64BIT 16439f53f9faSDan Williams depends on BLK_DEV 16447a67832cSDan Williams select X86_PMEM_LEGACY_DEVICE 16457b27a862SDan Williams select NUMA_KEEP_MEMINFO if NUMA 16469f53f9faSDan Williams select LIBNVDIMM 1647ec776ef6SChristoph Hellwig help 1648ec776ef6SChristoph Hellwig Treat memory marked using the non-standard e820 type of 12 as used 1649ec776ef6SChristoph Hellwig by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1650ec776ef6SChristoph Hellwig The kernel will offer these regions to the 'pmem' driver so 1651ec776ef6SChristoph Hellwig they can be used for persistent storage. 1652ec776ef6SChristoph Hellwig 1653ec776ef6SChristoph Hellwig Say Y if unsure. 1654ec776ef6SChristoph Hellwig 1655506f1d07SSam Ravnborgconfig HIGHPTE 1656506f1d07SSam Ravnborg bool "Allocate 3rd-level pagetables from highmem" 16576fc108a0SJan Beulich depends on HIGHMEM 1658a7f7f624SMasahiro Yamada help 1659506f1d07SSam Ravnborg The VM uses one page table entry for each page of physical memory. 1660506f1d07SSam Ravnborg For systems with a lot of RAM, this can be wasteful of precious 1661506f1d07SSam Ravnborg low memory. Setting this option will put user-space page table 1662506f1d07SSam Ravnborg entries in high memory. 1663506f1d07SSam Ravnborg 16649f077871SJeremy Fitzhardingeconfig X86_CHECK_BIOS_CORRUPTION 16659f077871SJeremy Fitzhardinge bool "Check for low memory corruption" 1666a7f7f624SMasahiro Yamada help 16679f077871SJeremy Fitzhardinge Periodically check for memory corruption in low memory, which 16689f077871SJeremy Fitzhardinge is suspected to be caused by BIOS. Even when enabled in the 16699f077871SJeremy Fitzhardinge configuration, it is disabled at runtime. Enable it by 16709f077871SJeremy Fitzhardinge setting "memory_corruption_check=1" on the kernel command 16719f077871SJeremy Fitzhardinge line. By default it scans the low 64k of memory every 60 16729f077871SJeremy Fitzhardinge seconds; see the memory_corruption_check_size and 16739f077871SJeremy Fitzhardinge memory_corruption_check_period parameters in 16748c27ceffSMauro Carvalho Chehab Documentation/admin-guide/kernel-parameters.rst to adjust this. 16759f077871SJeremy Fitzhardinge 16769f077871SJeremy Fitzhardinge When enabled with the default parameters, this option has 16779f077871SJeremy Fitzhardinge almost no overhead, as it reserves a relatively small amount 16789f077871SJeremy Fitzhardinge of memory and scans it infrequently. It both detects corruption 16799f077871SJeremy Fitzhardinge and prevents it from affecting the running system. 16809f077871SJeremy Fitzhardinge 16819f077871SJeremy Fitzhardinge It is, however, intended as a diagnostic tool; if repeatable 16829f077871SJeremy Fitzhardinge BIOS-originated corruption always affects the same memory, 16839f077871SJeremy Fitzhardinge you can use memmap= to prevent the kernel from using that 16849f077871SJeremy Fitzhardinge memory. 16859f077871SJeremy Fitzhardinge 1686c885df50SJeremy Fitzhardingeconfig X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1687c885df50SJeremy Fitzhardinge bool "Set the default setting of memory_corruption_check" 1688c885df50SJeremy Fitzhardinge depends on X86_CHECK_BIOS_CORRUPTION 1689c885df50SJeremy Fitzhardinge default y 1690a7f7f624SMasahiro Yamada help 1691c885df50SJeremy Fitzhardinge Set whether the default state of memory_corruption_check is 1692c885df50SJeremy Fitzhardinge on or off. 1693c885df50SJeremy Fitzhardinge 16949ea77bdbSH. Peter Anvinconfig X86_RESERVE_LOW 1695d0cd7425SH. Peter Anvin int "Amount of low memory, in kilobytes, to reserve for the BIOS" 1696d0cd7425SH. Peter Anvin default 64 1697d0cd7425SH. Peter Anvin range 4 640 1698a7f7f624SMasahiro Yamada help 1699d0cd7425SH. Peter Anvin Specify the amount of low memory to reserve for the BIOS. 1700fc381519SIngo Molnar 1701d0cd7425SH. Peter Anvin The first page contains BIOS data structures that the kernel 1702d0cd7425SH. Peter Anvin must not use, so that page must always be reserved. 1703fc381519SIngo Molnar 1704d0cd7425SH. Peter Anvin By default we reserve the first 64K of physical RAM, as a 1705d0cd7425SH. Peter Anvin number of BIOSes are known to corrupt that memory range 1706d0cd7425SH. Peter Anvin during events such as suspend/resume or monitor cable 1707d0cd7425SH. Peter Anvin insertion, so it must not be used by the kernel. 1708fc381519SIngo Molnar 1709d0cd7425SH. Peter Anvin You can set this to 4 if you are absolutely sure that you 1710d0cd7425SH. Peter Anvin trust the BIOS to get all its memory reservations and usages 1711d0cd7425SH. Peter Anvin right. If you know your BIOS have problems beyond the 1712d0cd7425SH. Peter Anvin default 64K area, you can set this to 640 to avoid using the 1713d0cd7425SH. Peter Anvin entire low memory range. 1714d0cd7425SH. Peter Anvin 1715d0cd7425SH. Peter Anvin If you have doubts about the BIOS (e.g. suspend/resume does 1716d0cd7425SH. Peter Anvin not work or there's kernel crashes after certain hardware 1717d0cd7425SH. Peter Anvin hotplug events) then you might want to enable 1718d0cd7425SH. Peter Anvin X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check 1719d0cd7425SH. Peter Anvin typical corruption patterns. 1720d0cd7425SH. Peter Anvin 1721d0cd7425SH. Peter Anvin Leave this to the default value of 64 if you are unsure. 1722fc381519SIngo Molnar 1723506f1d07SSam Ravnborgconfig MATH_EMULATION 1724506f1d07SSam Ravnborg bool 1725a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 172687d6021bSArnd Bergmann prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1727a7f7f624SMasahiro Yamada help 1728506f1d07SSam Ravnborg Linux can emulate a math coprocessor (used for floating point 1729506f1d07SSam Ravnborg operations) if you don't have one. 486DX and Pentium processors have 1730506f1d07SSam Ravnborg a math coprocessor built in, 486SX and 386 do not, unless you added 1731506f1d07SSam Ravnborg a 487DX or 387, respectively. (The messages during boot time can 1732506f1d07SSam Ravnborg give you some hints here ["man dmesg"].) Everyone needs either a 1733506f1d07SSam Ravnborg coprocessor or this emulation. 1734506f1d07SSam Ravnborg 1735506f1d07SSam Ravnborg If you don't have a math coprocessor, you need to say Y here; if you 1736506f1d07SSam Ravnborg say Y here even though you have a coprocessor, the coprocessor will 1737506f1d07SSam Ravnborg be used nevertheless. (This behavior can be changed with the kernel 1738506f1d07SSam Ravnborg command line option "no387", which comes handy if your coprocessor 1739506f1d07SSam Ravnborg is broken. Try "man bootparam" or see the documentation of your boot 1740506f1d07SSam Ravnborg loader (lilo or loadlin) about how to pass options to the kernel at 1741506f1d07SSam Ravnborg boot time.) This means that it is a good idea to say Y here if you 1742506f1d07SSam Ravnborg intend to use this kernel on different machines. 1743506f1d07SSam Ravnborg 1744506f1d07SSam Ravnborg More information about the internals of the Linux math coprocessor 1745506f1d07SSam Ravnborg emulation can be found in <file:arch/x86/math-emu/README>. 1746506f1d07SSam Ravnborg 1747506f1d07SSam Ravnborg If you are not sure, say Y; apart from resulting in a 66 KB bigger 1748506f1d07SSam Ravnborg kernel, it won't hurt. 1749506f1d07SSam Ravnborg 1750506f1d07SSam Ravnborgconfig MTRR 17516fc108a0SJan Beulich def_bool y 17526a108a14SDavid Rientjes prompt "MTRR (Memory Type Range Register) support" if EXPERT 1753a7f7f624SMasahiro Yamada help 1754506f1d07SSam Ravnborg On Intel P6 family processors (Pentium Pro, Pentium II and later) 1755506f1d07SSam Ravnborg the Memory Type Range Registers (MTRRs) may be used to control 1756506f1d07SSam Ravnborg processor access to memory ranges. This is most useful if you have 1757506f1d07SSam Ravnborg a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1758506f1d07SSam Ravnborg allows bus write transfers to be combined into a larger transfer 1759506f1d07SSam Ravnborg before bursting over the PCI/AGP bus. This can increase performance 1760506f1d07SSam Ravnborg of image write operations 2.5 times or more. Saying Y here creates a 1761506f1d07SSam Ravnborg /proc/mtrr file which may be used to manipulate your processor's 1762506f1d07SSam Ravnborg MTRRs. Typically the X server should use this. 1763506f1d07SSam Ravnborg 1764506f1d07SSam Ravnborg This code has a reasonably generic interface so that similar 1765506f1d07SSam Ravnborg control registers on other processors can be easily supported 1766506f1d07SSam Ravnborg as well: 1767506f1d07SSam Ravnborg 1768506f1d07SSam Ravnborg The Cyrix 6x86, 6x86MX and M II processors have Address Range 1769506f1d07SSam Ravnborg Registers (ARRs) which provide a similar functionality to MTRRs. For 1770506f1d07SSam Ravnborg these, the ARRs are used to emulate the MTRRs. 1771506f1d07SSam Ravnborg The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1772506f1d07SSam Ravnborg MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1773506f1d07SSam Ravnborg write-combining. All of these processors are supported by this code 1774506f1d07SSam Ravnborg and it makes sense to say Y here if you have one of them. 1775506f1d07SSam Ravnborg 1776506f1d07SSam Ravnborg Saying Y here also fixes a problem with buggy SMP BIOSes which only 1777506f1d07SSam Ravnborg set the MTRRs for the boot CPU and not for the secondary CPUs. This 1778506f1d07SSam Ravnborg can lead to all sorts of problems, so it's good to say Y here. 1779506f1d07SSam Ravnborg 1780506f1d07SSam Ravnborg You can safely say Y even if your machine doesn't have MTRRs, you'll 1781506f1d07SSam Ravnborg just add about 9 KB to your kernel. 1782506f1d07SSam Ravnborg 1783cb1aaebeSMauro Carvalho Chehab See <file:Documentation/x86/mtrr.rst> for more information. 1784506f1d07SSam Ravnborg 178595ffa243SYinghai Luconfig MTRR_SANITIZER 17862ffb3501SYinghai Lu def_bool y 178795ffa243SYinghai Lu prompt "MTRR cleanup support" 178895ffa243SYinghai Lu depends on MTRR 1789a7f7f624SMasahiro Yamada help 1790aba3728cSThomas Gleixner Convert MTRR layout from continuous to discrete, so X drivers can 1791aba3728cSThomas Gleixner add writeback entries. 179295ffa243SYinghai Lu 1793aba3728cSThomas Gleixner Can be disabled with disable_mtrr_cleanup on the kernel command line. 1794692105b8SMatt LaPlante The largest mtrr entry size for a continuous block can be set with 1795aba3728cSThomas Gleixner mtrr_chunk_size. 179695ffa243SYinghai Lu 17972ffb3501SYinghai Lu If unsure, say Y. 179895ffa243SYinghai Lu 179995ffa243SYinghai Luconfig MTRR_SANITIZER_ENABLE_DEFAULT 1800f5098d62SYinghai Lu int "MTRR cleanup enable value (0-1)" 1801f5098d62SYinghai Lu range 0 1 1802f5098d62SYinghai Lu default "0" 180395ffa243SYinghai Lu depends on MTRR_SANITIZER 1804a7f7f624SMasahiro Yamada help 1805f5098d62SYinghai Lu Enable mtrr cleanup default value 180695ffa243SYinghai Lu 180712031a62SYinghai Luconfig MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 180812031a62SYinghai Lu int "MTRR cleanup spare reg num (0-7)" 180912031a62SYinghai Lu range 0 7 181012031a62SYinghai Lu default "1" 181112031a62SYinghai Lu depends on MTRR_SANITIZER 1812a7f7f624SMasahiro Yamada help 181312031a62SYinghai Lu mtrr cleanup spare entries default, it can be changed via 1814aba3728cSThomas Gleixner mtrr_spare_reg_nr=N on the kernel command line. 181512031a62SYinghai Lu 18162e5d9c85Svenkatesh.pallipadi@intel.comconfig X86_PAT 18176fc108a0SJan Beulich def_bool y 18186a108a14SDavid Rientjes prompt "x86 PAT support" if EXPERT 18192a8a2719SIngo Molnar depends on MTRR 1820a7f7f624SMasahiro Yamada help 18212e5d9c85Svenkatesh.pallipadi@intel.com Use PAT attributes to setup page level cache control. 1822042b78e4SVenki Pallipadi 18232e5d9c85Svenkatesh.pallipadi@intel.com PATs are the modern equivalents of MTRRs and are much more 18242e5d9c85Svenkatesh.pallipadi@intel.com flexible than MTRRs. 18252e5d9c85Svenkatesh.pallipadi@intel.com 18262e5d9c85Svenkatesh.pallipadi@intel.com Say N here if you see bootup problems (boot crash, boot hang, 1827042b78e4SVenki Pallipadi spontaneous reboots) or a non-working video driver. 18282e5d9c85Svenkatesh.pallipadi@intel.com 18292e5d9c85Svenkatesh.pallipadi@intel.com If unsure, say Y. 18302e5d9c85Svenkatesh.pallipadi@intel.com 183146cf98cdSVenkatesh Pallipadiconfig ARCH_USES_PG_UNCACHED 183246cf98cdSVenkatesh Pallipadi def_bool y 183346cf98cdSVenkatesh Pallipadi depends on X86_PAT 183446cf98cdSVenkatesh Pallipadi 1835628c6246SH. Peter Anvinconfig ARCH_RANDOM 1836628c6246SH. Peter Anvin def_bool y 1837628c6246SH. Peter Anvin prompt "x86 architectural random number generator" if EXPERT 1838a7f7f624SMasahiro Yamada help 1839628c6246SH. Peter Anvin Enable the x86 architectural RDRAND instruction 1840628c6246SH. Peter Anvin (Intel Bull Mountain technology) to generate random numbers. 1841628c6246SH. Peter Anvin If supported, this is a high bandwidth, cryptographically 1842628c6246SH. Peter Anvin secure hardware random number generator. 1843628c6246SH. Peter Anvin 184451ae4a2dSH. Peter Anvinconfig X86_SMAP 184551ae4a2dSH. Peter Anvin def_bool y 184651ae4a2dSH. Peter Anvin prompt "Supervisor Mode Access Prevention" if EXPERT 1847a7f7f624SMasahiro Yamada help 184851ae4a2dSH. Peter Anvin Supervisor Mode Access Prevention (SMAP) is a security 184951ae4a2dSH. Peter Anvin feature in newer Intel processors. There is a small 185051ae4a2dSH. Peter Anvin performance cost if this enabled and turned on; there is 185151ae4a2dSH. Peter Anvin also a small increase in the kernel size if this is enabled. 185251ae4a2dSH. Peter Anvin 185351ae4a2dSH. Peter Anvin If unsure, say Y. 185451ae4a2dSH. Peter Anvin 1855b971880fSBabu Mogerconfig X86_UMIP 1856796ebc81SRicardo Neri def_bool y 1857b971880fSBabu Moger prompt "User Mode Instruction Prevention" if EXPERT 1858a7f7f624SMasahiro Yamada help 1859b971880fSBabu Moger User Mode Instruction Prevention (UMIP) is a security feature in 1860b971880fSBabu Moger some x86 processors. If enabled, a general protection fault is 1861b971880fSBabu Moger issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1862b971880fSBabu Moger executed in user mode. These instructions unnecessarily expose 1863b971880fSBabu Moger information about the hardware state. 1864796ebc81SRicardo Neri 1865796ebc81SRicardo Neri The vast majority of applications do not use these instructions. 1866796ebc81SRicardo Neri For the very few that do, software emulation is provided in 1867796ebc81SRicardo Neri specific cases in protected and virtual-8086 modes. Emulated 1868796ebc81SRicardo Neri results are dummy. 1869aa35f896SRicardo Neri 187035e97790SDave Hansenconfig X86_INTEL_MEMORY_PROTECTION_KEYS 187138f3e775SBabu Moger prompt "Memory Protection Keys" 187235e97790SDave Hansen def_bool y 1873284244a9SDave Hansen # Note: only available in 64-bit mode 187438f3e775SBabu Moger depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 187552c8e601SIngo Molnar select ARCH_USES_HIGH_VMA_FLAGS 187652c8e601SIngo Molnar select ARCH_HAS_PKEYS 1877a7f7f624SMasahiro Yamada help 1878284244a9SDave Hansen Memory Protection Keys provides a mechanism for enforcing 1879284244a9SDave Hansen page-based protections, but without requiring modification of the 1880284244a9SDave Hansen page tables when an application changes protection domains. 1881284244a9SDave Hansen 18821eecbcdcSMauro Carvalho Chehab For details, see Documentation/core-api/protection-keys.rst 1883284244a9SDave Hansen 1884284244a9SDave Hansen If unsure, say y. 188535e97790SDave Hansen 1886db616173SMichal Hockochoice 1887db616173SMichal Hocko prompt "TSX enable mode" 1888db616173SMichal Hocko depends on CPU_SUP_INTEL 1889db616173SMichal Hocko default X86_INTEL_TSX_MODE_OFF 1890db616173SMichal Hocko help 1891db616173SMichal Hocko Intel's TSX (Transactional Synchronization Extensions) feature 1892db616173SMichal Hocko allows to optimize locking protocols through lock elision which 1893db616173SMichal Hocko can lead to a noticeable performance boost. 1894db616173SMichal Hocko 1895db616173SMichal Hocko On the other hand it has been shown that TSX can be exploited 1896db616173SMichal Hocko to form side channel attacks (e.g. TAA) and chances are there 1897db616173SMichal Hocko will be more of those attacks discovered in the future. 1898db616173SMichal Hocko 1899db616173SMichal Hocko Therefore TSX is not enabled by default (aka tsx=off). An admin 1900db616173SMichal Hocko might override this decision by tsx=on the command line parameter. 1901db616173SMichal Hocko Even with TSX enabled, the kernel will attempt to enable the best 1902db616173SMichal Hocko possible TAA mitigation setting depending on the microcode available 1903db616173SMichal Hocko for the particular machine. 1904db616173SMichal Hocko 1905db616173SMichal Hocko This option allows to set the default tsx mode between tsx=on, =off 1906db616173SMichal Hocko and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1907db616173SMichal Hocko details. 1908db616173SMichal Hocko 1909db616173SMichal Hocko Say off if not sure, auto if TSX is in use but it should be used on safe 1910db616173SMichal Hocko platforms or on if TSX is in use and the security aspect of tsx is not 1911db616173SMichal Hocko relevant. 1912db616173SMichal Hocko 1913db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_OFF 1914db616173SMichal Hocko bool "off" 1915db616173SMichal Hocko help 1916db616173SMichal Hocko TSX is disabled if possible - equals to tsx=off command line parameter. 1917db616173SMichal Hocko 1918db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_ON 1919db616173SMichal Hocko bool "on" 1920db616173SMichal Hocko help 1921db616173SMichal Hocko TSX is always enabled on TSX capable HW - equals the tsx=on command 1922db616173SMichal Hocko line parameter. 1923db616173SMichal Hocko 1924db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_AUTO 1925db616173SMichal Hocko bool "auto" 1926db616173SMichal Hocko help 1927db616173SMichal Hocko TSX is enabled on TSX capable HW that is believed to be safe against 1928db616173SMichal Hocko side channel attacks- equals the tsx=auto command line parameter. 1929db616173SMichal Hockoendchoice 1930db616173SMichal Hocko 1931506f1d07SSam Ravnborgconfig EFI 19329ba16087SJan Beulich bool "EFI runtime service support" 19335b83683fSHuang, Ying depends on ACPI 1934f6ce5002SSergey Vlasov select UCS2_STRING 1935022ee6c5SArd Biesheuvel select EFI_RUNTIME_WRAPPERS 1936a7f7f624SMasahiro Yamada help 19378b2cb7a8SHuang, Ying This enables the kernel to use EFI runtime services that are 1938506f1d07SSam Ravnborg available (such as the EFI variable services). 1939506f1d07SSam Ravnborg 19408b2cb7a8SHuang, Ying This option is only useful on systems that have EFI firmware. 19418b2cb7a8SHuang, Ying In addition, you should use the latest ELILO loader available 19428b2cb7a8SHuang, Ying at <http://elilo.sourceforge.net> in order to take advantage 19438b2cb7a8SHuang, Ying of EFI runtime services. However, even with this option, the 19448b2cb7a8SHuang, Ying resultant kernel should continue to boot on existing non-EFI 19458b2cb7a8SHuang, Ying platforms. 1946506f1d07SSam Ravnborg 1947291f3632SMatt Flemingconfig EFI_STUB 1948291f3632SMatt Fleming bool "EFI stub support" 1949b16d8c23SMatt Fleming depends on EFI && !X86_USE_3DNOW 19508f24f8c2SArd Biesheuvel depends on $(cc-option,-mabi=ms) || X86_32 19517b2a583aSMatt Fleming select RELOCATABLE 1952a7f7f624SMasahiro Yamada help 1953291f3632SMatt Fleming This kernel feature allows a bzImage to be loaded directly 1954291f3632SMatt Fleming by EFI firmware without the use of a bootloader. 1955291f3632SMatt Fleming 19564f4cfa6cSMauro Carvalho Chehab See Documentation/admin-guide/efi-stub.rst for more information. 19570c759662SMatt Fleming 19587d453eeeSMatt Flemingconfig EFI_MIXED 19597d453eeeSMatt Fleming bool "EFI mixed-mode support" 19607d453eeeSMatt Fleming depends on EFI_STUB && X86_64 1961a7f7f624SMasahiro Yamada help 19627d453eeeSMatt Fleming Enabling this feature allows a 64-bit kernel to be booted 19637d453eeeSMatt Fleming on a 32-bit firmware, provided that your CPU supports 64-bit 19647d453eeeSMatt Fleming mode. 19657d453eeeSMatt Fleming 19667d453eeeSMatt Fleming Note that it is not possible to boot a mixed-mode enabled 19677d453eeeSMatt Fleming kernel via the EFI boot stub - a bootloader that supports 19687d453eeeSMatt Fleming the EFI handover protocol must be used. 19697d453eeeSMatt Fleming 19707d453eeeSMatt Fleming If unsure, say N. 19717d453eeeSMatt Fleming 1972506f1d07SSam Ravnborgconfig SECCOMP 19733c2362e6SHarvey Harrison def_bool y 19743c2362e6SHarvey Harrison prompt "Enable seccomp to safely compute untrusted bytecode" 1975a7f7f624SMasahiro Yamada help 1976506f1d07SSam Ravnborg This kernel feature is useful for number crunching applications 1977506f1d07SSam Ravnborg that may need to compute untrusted bytecode during their 1978506f1d07SSam Ravnborg execution. By using pipes or other transports made available to 1979506f1d07SSam Ravnborg the process as file descriptors supporting the read/write 1980506f1d07SSam Ravnborg syscalls, it's possible to isolate those applications in 1981506f1d07SSam Ravnborg their own address space using seccomp. Once seccomp is 19829c0bbee8SAlexey Dobriyan enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 1983506f1d07SSam Ravnborg and the task is only allowed to execute a few safe syscalls 1984506f1d07SSam Ravnborg defined by each seccomp mode. 1985506f1d07SSam Ravnborg 1986506f1d07SSam Ravnborg If unsure, say Y. Only embedded should say N here. 1987506f1d07SSam Ravnborg 19888636a1f9SMasahiro Yamadasource "kernel/Kconfig.hz" 1989506f1d07SSam Ravnborg 1990506f1d07SSam Ravnborgconfig KEXEC 1991506f1d07SSam Ravnborg bool "kexec system call" 19922965faa5SDave Young select KEXEC_CORE 1993a7f7f624SMasahiro Yamada help 1994506f1d07SSam Ravnborg kexec is a system call that implements the ability to shutdown your 1995506f1d07SSam Ravnborg current kernel, and to start another kernel. It is like a reboot 1996506f1d07SSam Ravnborg but it is independent of the system firmware. And like a reboot 1997506f1d07SSam Ravnborg you can start any kernel with it, not just Linux. 1998506f1d07SSam Ravnborg 1999506f1d07SSam Ravnborg The name comes from the similarity to the exec system call. 2000506f1d07SSam Ravnborg 2001506f1d07SSam Ravnborg It is an ongoing process to be certain the hardware in a machine 2002506f1d07SSam Ravnborg is properly shutdown, so do not be surprised if this code does not 2003bf220695SGeert Uytterhoeven initially work for you. As of this writing the exact hardware 2004bf220695SGeert Uytterhoeven interface is strongly in flux, so no good recommendation can be 2005bf220695SGeert Uytterhoeven made. 2006506f1d07SSam Ravnborg 200774ca317cSVivek Goyalconfig KEXEC_FILE 200874ca317cSVivek Goyal bool "kexec file based system call" 20092965faa5SDave Young select KEXEC_CORE 201074ca317cSVivek Goyal select BUILD_BIN2C 201174ca317cSVivek Goyal depends on X86_64 201274ca317cSVivek Goyal depends on CRYPTO=y 201374ca317cSVivek Goyal depends on CRYPTO_SHA256=y 2014a7f7f624SMasahiro Yamada help 201574ca317cSVivek Goyal This is new version of kexec system call. This system call is 201674ca317cSVivek Goyal file based and takes file descriptors as system call argument 201774ca317cSVivek Goyal for kernel and initramfs as opposed to list of segments as 201874ca317cSVivek Goyal accepted by previous system call. 201974ca317cSVivek Goyal 2020b799a09fSAKASHI Takahiroconfig ARCH_HAS_KEXEC_PURGATORY 2021b799a09fSAKASHI Takahiro def_bool KEXEC_FILE 2022b799a09fSAKASHI Takahiro 202399d5cadfSJiri Bohacconfig KEXEC_SIG 20248e7d8381SVivek Goyal bool "Verify kernel signature during kexec_file_load() syscall" 202574ca317cSVivek Goyal depends on KEXEC_FILE 2026a7f7f624SMasahiro Yamada help 202799d5cadfSJiri Bohac 202899d5cadfSJiri Bohac This option makes the kexec_file_load() syscall check for a valid 202999d5cadfSJiri Bohac signature of the kernel image. The image can still be loaded without 203099d5cadfSJiri Bohac a valid signature unless you also enable KEXEC_SIG_FORCE, though if 203199d5cadfSJiri Bohac there's a signature that we can check, then it must be valid. 203299d5cadfSJiri Bohac 203399d5cadfSJiri Bohac In addition to this option, you need to enable signature 203499d5cadfSJiri Bohac verification for the corresponding kernel image type being 203599d5cadfSJiri Bohac loaded in order for this to work. 203699d5cadfSJiri Bohac 203799d5cadfSJiri Bohacconfig KEXEC_SIG_FORCE 203899d5cadfSJiri Bohac bool "Require a valid signature in kexec_file_load() syscall" 203999d5cadfSJiri Bohac depends on KEXEC_SIG 2040a7f7f624SMasahiro Yamada help 20418e7d8381SVivek Goyal This option makes kernel signature verification mandatory for 2042d8eb8940SBorislav Petkov the kexec_file_load() syscall. 20438e7d8381SVivek Goyal 20448e7d8381SVivek Goyalconfig KEXEC_BZIMAGE_VERIFY_SIG 20458e7d8381SVivek Goyal bool "Enable bzImage signature verification support" 204699d5cadfSJiri Bohac depends on KEXEC_SIG 20478e7d8381SVivek Goyal depends on SIGNED_PE_FILE_VERIFICATION 20488e7d8381SVivek Goyal select SYSTEM_TRUSTED_KEYRING 2049a7f7f624SMasahiro Yamada help 20508e7d8381SVivek Goyal Enable bzImage signature verification support. 20518e7d8381SVivek Goyal 2052506f1d07SSam Ravnborgconfig CRASH_DUMP 205304b69447SPavel Machek bool "kernel crash dumps" 2054506f1d07SSam Ravnborg depends on X86_64 || (X86_32 && HIGHMEM) 2055a7f7f624SMasahiro Yamada help 2056506f1d07SSam Ravnborg Generate crash dump after being started by kexec. 2057506f1d07SSam Ravnborg This should be normally only set in special crash dump kernels 2058506f1d07SSam Ravnborg which are loaded in the main kernel with kexec-tools into 2059506f1d07SSam Ravnborg a specially reserved region and then later executed after 2060506f1d07SSam Ravnborg a crash by kdump/kexec. The crash dump kernel must be compiled 2061506f1d07SSam Ravnborg to a memory address not used by the main kernel or BIOS using 2062506f1d07SSam Ravnborg PHYSICAL_START, or it must be built as a relocatable image 2063506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y). 2064330d4810SMauro Carvalho Chehab For more details see Documentation/admin-guide/kdump/kdump.rst 2065506f1d07SSam Ravnborg 20663ab83521SHuang Yingconfig KEXEC_JUMP 20676ea30386SKees Cook bool "kexec jump" 2068fee7b0d8SHuang Ying depends on KEXEC && HIBERNATION 2069a7f7f624SMasahiro Yamada help 207089081d17SHuang Ying Jump between original kernel and kexeced kernel and invoke 207189081d17SHuang Ying code in physical address mode via KEXEC 20723ab83521SHuang Ying 2073506f1d07SSam Ravnborgconfig PHYSICAL_START 20746a108a14SDavid Rientjes hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2075ceefccc9SH. Peter Anvin default "0x1000000" 2076a7f7f624SMasahiro Yamada help 2077506f1d07SSam Ravnborg This gives the physical address where the kernel is loaded. 2078506f1d07SSam Ravnborg 2079506f1d07SSam Ravnborg If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2080506f1d07SSam Ravnborg bzImage will decompress itself to above physical address and 2081506f1d07SSam Ravnborg run from there. Otherwise, bzImage will run from the address where 2082506f1d07SSam Ravnborg it has been loaded by the boot loader and will ignore above physical 2083506f1d07SSam Ravnborg address. 2084506f1d07SSam Ravnborg 2085506f1d07SSam Ravnborg In normal kdump cases one does not have to set/change this option 2086506f1d07SSam Ravnborg as now bzImage can be compiled as a completely relocatable image 2087506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2088506f1d07SSam Ravnborg address. This option is mainly useful for the folks who don't want 2089506f1d07SSam Ravnborg to use a bzImage for capturing the crash dump and want to use a 2090506f1d07SSam Ravnborg vmlinux instead. vmlinux is not relocatable hence a kernel needs 2091506f1d07SSam Ravnborg to be specifically compiled to run from a specific memory area 2092506f1d07SSam Ravnborg (normally a reserved region) and this option comes handy. 2093506f1d07SSam Ravnborg 2094ceefccc9SH. Peter Anvin So if you are using bzImage for capturing the crash dump, 2095ceefccc9SH. Peter Anvin leave the value here unchanged to 0x1000000 and set 2096ceefccc9SH. Peter Anvin CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2097ceefccc9SH. Peter Anvin for capturing the crash dump change this value to start of 2098ceefccc9SH. Peter Anvin the reserved region. In other words, it can be set based on 2099ceefccc9SH. Peter Anvin the "X" value as specified in the "crashkernel=YM@XM" 2100ceefccc9SH. Peter Anvin command line boot parameter passed to the panic-ed 2101330d4810SMauro Carvalho Chehab kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2102ceefccc9SH. Peter Anvin for more details about crash dumps. 2103506f1d07SSam Ravnborg 2104506f1d07SSam Ravnborg Usage of bzImage for capturing the crash dump is recommended as 2105506f1d07SSam Ravnborg one does not have to build two kernels. Same kernel can be used 2106506f1d07SSam Ravnborg as production kernel and capture kernel. Above option should have 2107506f1d07SSam Ravnborg gone away after relocatable bzImage support is introduced. But it 2108506f1d07SSam Ravnborg is present because there are users out there who continue to use 2109506f1d07SSam Ravnborg vmlinux for dump capture. This option should go away down the 2110506f1d07SSam Ravnborg line. 2111506f1d07SSam Ravnborg 2112506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2113506f1d07SSam Ravnborg 2114506f1d07SSam Ravnborgconfig RELOCATABLE 211526717808SH. Peter Anvin bool "Build a relocatable kernel" 211626717808SH. Peter Anvin default y 2117a7f7f624SMasahiro Yamada help 2118506f1d07SSam Ravnborg This builds a kernel image that retains relocation information 2119506f1d07SSam Ravnborg so it can be loaded someplace besides the default 1MB. 2120506f1d07SSam Ravnborg The relocations tend to make the kernel binary about 10% larger, 2121506f1d07SSam Ravnborg but are discarded at runtime. 2122506f1d07SSam Ravnborg 2123506f1d07SSam Ravnborg One use is for the kexec on panic case where the recovery kernel 2124506f1d07SSam Ravnborg must live at a different physical address than the primary 2125506f1d07SSam Ravnborg kernel. 2126506f1d07SSam Ravnborg 2127506f1d07SSam Ravnborg Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2128506f1d07SSam Ravnborg it has been loaded at and the compile time physical address 21298ab3820fSKees Cook (CONFIG_PHYSICAL_START) is used as the minimum location. 2130506f1d07SSam Ravnborg 21318ab3820fSKees Cookconfig RANDOMIZE_BASE 2132e8581e3dSBaoquan He bool "Randomize the address of the kernel image (KASLR)" 21338ab3820fSKees Cook depends on RELOCATABLE 21346807c846SIngo Molnar default y 2135a7f7f624SMasahiro Yamada help 2136e8581e3dSBaoquan He In support of Kernel Address Space Layout Randomization (KASLR), 2137e8581e3dSBaoquan He this randomizes the physical address at which the kernel image 2138e8581e3dSBaoquan He is decompressed and the virtual address where the kernel 2139e8581e3dSBaoquan He image is mapped, as a security feature that deters exploit 2140e8581e3dSBaoquan He attempts relying on knowledge of the location of kernel 2141e8581e3dSBaoquan He code internals. 2142e8581e3dSBaoquan He 2143ed9f007eSKees Cook On 64-bit, the kernel physical and virtual addresses are 2144ed9f007eSKees Cook randomized separately. The physical address will be anywhere 2145ed9f007eSKees Cook between 16MB and the top of physical memory (up to 64TB). The 2146ed9f007eSKees Cook virtual address will be randomized from 16MB up to 1GB (9 bits 2147ed9f007eSKees Cook of entropy). Note that this also reduces the memory space 2148ed9f007eSKees Cook available to kernel modules from 1.5GB to 1GB. 2149ed9f007eSKees Cook 2150ed9f007eSKees Cook On 32-bit, the kernel physical and virtual addresses are 2151ed9f007eSKees Cook randomized together. They will be randomized from 16MB up to 2152ed9f007eSKees Cook 512MB (8 bits of entropy). 21538ab3820fSKees Cook 2154a653f356SKees Cook Entropy is generated using the RDRAND instruction if it is 2155e8581e3dSBaoquan He supported. If RDTSC is supported, its value is mixed into 2156e8581e3dSBaoquan He the entropy pool as well. If neither RDRAND nor RDTSC are 2157ed9f007eSKees Cook supported, then entropy is read from the i8254 timer. The 2158ed9f007eSKees Cook usable entropy is limited by the kernel being built using 2159ed9f007eSKees Cook 2GB addressing, and that PHYSICAL_ALIGN must be at a 2160ed9f007eSKees Cook minimum of 2MB. As a result, only 10 bits of entropy are 2161ed9f007eSKees Cook theoretically possible, but the implementations are further 2162ed9f007eSKees Cook limited due to memory layouts. 2163e8581e3dSBaoquan He 21646807c846SIngo Molnar If unsure, say Y. 2165da2b6fb9SKees Cook 21668ab3820fSKees Cook# Relocation on x86 needs some additional build support 2167845adf72SH. Peter Anvinconfig X86_NEED_RELOCS 2168845adf72SH. Peter Anvin def_bool y 21698ab3820fSKees Cook depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2170845adf72SH. Peter Anvin 2171506f1d07SSam Ravnborgconfig PHYSICAL_ALIGN 2172a0215061SKees Cook hex "Alignment value to which kernel should be aligned" 21738ab3820fSKees Cook default "0x200000" 2174a0215061SKees Cook range 0x2000 0x1000000 if X86_32 2175a0215061SKees Cook range 0x200000 0x1000000 if X86_64 2176a7f7f624SMasahiro Yamada help 2177506f1d07SSam Ravnborg This value puts the alignment restrictions on physical address 2178506f1d07SSam Ravnborg where kernel is loaded and run from. Kernel is compiled for an 2179506f1d07SSam Ravnborg address which meets above alignment restriction. 2180506f1d07SSam Ravnborg 2181506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2182506f1d07SSam Ravnborg CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2183506f1d07SSam Ravnborg address aligned to above value and run from there. 2184506f1d07SSam Ravnborg 2185506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2186506f1d07SSam Ravnborg CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2187506f1d07SSam Ravnborg load address and decompress itself to the address it has been 2188506f1d07SSam Ravnborg compiled for and run from there. The address for which kernel is 2189506f1d07SSam Ravnborg compiled already meets above alignment restrictions. Hence the 2190506f1d07SSam Ravnborg end result is that kernel runs from a physical address meeting 2191506f1d07SSam Ravnborg above alignment restrictions. 2192506f1d07SSam Ravnborg 2193a0215061SKees Cook On 32-bit this value must be a multiple of 0x2000. On 64-bit 2194a0215061SKees Cook this value must be a multiple of 0x200000. 2195a0215061SKees Cook 2196506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2197506f1d07SSam Ravnborg 2198eedb92abSKirill A. Shutemovconfig DYNAMIC_MEMORY_LAYOUT 2199eedb92abSKirill A. Shutemov bool 2200a7f7f624SMasahiro Yamada help 2201eedb92abSKirill A. Shutemov This option makes base addresses of vmalloc and vmemmap as well as 2202eedb92abSKirill A. Shutemov __PAGE_OFFSET movable during boot. 2203eedb92abSKirill A. Shutemov 22040483e1faSThomas Garnierconfig RANDOMIZE_MEMORY 22050483e1faSThomas Garnier bool "Randomize the kernel memory sections" 22060483e1faSThomas Garnier depends on X86_64 22070483e1faSThomas Garnier depends on RANDOMIZE_BASE 2208eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 22090483e1faSThomas Garnier default RANDOMIZE_BASE 2210a7f7f624SMasahiro Yamada help 22110483e1faSThomas Garnier Randomizes the base virtual address of kernel memory sections 22120483e1faSThomas Garnier (physical memory mapping, vmalloc & vmemmap). This security feature 22130483e1faSThomas Garnier makes exploits relying on predictable memory locations less reliable. 22140483e1faSThomas Garnier 22150483e1faSThomas Garnier The order of allocations remains unchanged. Entropy is generated in 22160483e1faSThomas Garnier the same way as RANDOMIZE_BASE. Current implementation in the optimal 22170483e1faSThomas Garnier configuration have in average 30,000 different possible virtual 22180483e1faSThomas Garnier addresses for each memory section. 22190483e1faSThomas Garnier 22206807c846SIngo Molnar If unsure, say Y. 22210483e1faSThomas Garnier 222290397a41SThomas Garnierconfig RANDOMIZE_MEMORY_PHYSICAL_PADDING 222390397a41SThomas Garnier hex "Physical memory mapping padding" if EXPERT 222490397a41SThomas Garnier depends on RANDOMIZE_MEMORY 222590397a41SThomas Garnier default "0xa" if MEMORY_HOTPLUG 222690397a41SThomas Garnier default "0x0" 222790397a41SThomas Garnier range 0x1 0x40 if MEMORY_HOTPLUG 222890397a41SThomas Garnier range 0x0 0x40 2229a7f7f624SMasahiro Yamada help 223090397a41SThomas Garnier Define the padding in terabytes added to the existing physical 223190397a41SThomas Garnier memory size during kernel memory randomization. It is useful 223290397a41SThomas Garnier for memory hotplug support but reduces the entropy available for 223390397a41SThomas Garnier address randomization. 223490397a41SThomas Garnier 223590397a41SThomas Garnier If unsure, leave at the default value. 223690397a41SThomas Garnier 2237506f1d07SSam Ravnborgconfig HOTPLUG_CPU 2238bebd024eSThomas Gleixner def_bool y 223940b31360SStephen Rothwell depends on SMP 2240506f1d07SSam Ravnborg 224180aa1dffSFenghua Yuconfig BOOTPARAM_HOTPLUG_CPU0 224280aa1dffSFenghua Yu bool "Set default setting of cpu0_hotpluggable" 22432c922cd0SKees Cook depends on HOTPLUG_CPU 2244a7f7f624SMasahiro Yamada help 224580aa1dffSFenghua Yu Set whether default state of cpu0_hotpluggable is on or off. 224680aa1dffSFenghua Yu 224780aa1dffSFenghua Yu Say Y here to enable CPU0 hotplug by default. If this switch 224880aa1dffSFenghua Yu is turned on, there is no need to give cpu0_hotplug kernel 224980aa1dffSFenghua Yu parameter and the CPU0 hotplug feature is enabled by default. 225080aa1dffSFenghua Yu 225180aa1dffSFenghua Yu Please note: there are two known CPU0 dependencies if you want 225280aa1dffSFenghua Yu to enable the CPU0 hotplug feature either by this switch or by 225380aa1dffSFenghua Yu cpu0_hotplug kernel parameter. 225480aa1dffSFenghua Yu 225580aa1dffSFenghua Yu First, resume from hibernate or suspend always starts from CPU0. 225680aa1dffSFenghua Yu So hibernate and suspend are prevented if CPU0 is offline. 225780aa1dffSFenghua Yu 225880aa1dffSFenghua Yu Second dependency is PIC interrupts always go to CPU0. CPU0 can not 225980aa1dffSFenghua Yu offline if any interrupt can not migrate out of CPU0. There may 226080aa1dffSFenghua Yu be other CPU0 dependencies. 226180aa1dffSFenghua Yu 226280aa1dffSFenghua Yu Please make sure the dependencies are under your control before 226380aa1dffSFenghua Yu you enable this feature. 226480aa1dffSFenghua Yu 226580aa1dffSFenghua Yu Say N if you don't want to enable CPU0 hotplug feature by default. 226680aa1dffSFenghua Yu You still can enable the CPU0 hotplug feature at boot by kernel 226780aa1dffSFenghua Yu parameter cpu0_hotplug. 226880aa1dffSFenghua Yu 2269a71c8bc5SFenghua Yuconfig DEBUG_HOTPLUG_CPU0 2270a71c8bc5SFenghua Yu def_bool n 2271a71c8bc5SFenghua Yu prompt "Debug CPU0 hotplug" 22722c922cd0SKees Cook depends on HOTPLUG_CPU 2273a7f7f624SMasahiro Yamada help 2274a71c8bc5SFenghua Yu Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2275a71c8bc5SFenghua Yu soon as possible and boots up userspace with CPU0 offlined. User 2276a71c8bc5SFenghua Yu can online CPU0 back after boot time. 2277a71c8bc5SFenghua Yu 2278a71c8bc5SFenghua Yu To debug CPU0 hotplug, you need to enable CPU0 offline/online 2279a71c8bc5SFenghua Yu feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2280a71c8bc5SFenghua Yu compilation or giving cpu0_hotplug kernel parameter at boot. 2281a71c8bc5SFenghua Yu 2282a71c8bc5SFenghua Yu If unsure, say N. 2283a71c8bc5SFenghua Yu 2284506f1d07SSam Ravnborgconfig COMPAT_VDSO 2285b0b49f26SAndy Lutomirski def_bool n 2286b0b49f26SAndy Lutomirski prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2287953fee1dSIngo Molnar depends on COMPAT_32 2288a7f7f624SMasahiro Yamada help 2289b0b49f26SAndy Lutomirski Certain buggy versions of glibc will crash if they are 2290b0b49f26SAndy Lutomirski presented with a 32-bit vDSO that is not mapped at the address 2291b0b49f26SAndy Lutomirski indicated in its segment table. 2292e84446deSRandy Dunlap 2293b0b49f26SAndy Lutomirski The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2294b0b49f26SAndy Lutomirski and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2295b0b49f26SAndy Lutomirski 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2296b0b49f26SAndy Lutomirski the only released version with the bug, but OpenSUSE 9 2297b0b49f26SAndy Lutomirski contains a buggy "glibc 2.3.2". 2298506f1d07SSam Ravnborg 2299b0b49f26SAndy Lutomirski The symptom of the bug is that everything crashes on startup, saying: 2300b0b49f26SAndy Lutomirski dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2301b0b49f26SAndy Lutomirski 2302b0b49f26SAndy Lutomirski Saying Y here changes the default value of the vdso32 boot 2303b0b49f26SAndy Lutomirski option from 1 to 0, which turns off the 32-bit vDSO entirely. 2304b0b49f26SAndy Lutomirski This works around the glibc bug but hurts performance. 2305b0b49f26SAndy Lutomirski 2306b0b49f26SAndy Lutomirski If unsure, say N: if you are compiling your own kernel, you 2307b0b49f26SAndy Lutomirski are unlikely to be using a buggy version of glibc. 2308506f1d07SSam Ravnborg 23093dc33bd3SKees Cookchoice 23103dc33bd3SKees Cook prompt "vsyscall table for legacy applications" 23113dc33bd3SKees Cook depends on X86_64 2312625b7b7fSAndy Lutomirski default LEGACY_VSYSCALL_XONLY 23133dc33bd3SKees Cook help 23143dc33bd3SKees Cook Legacy user code that does not know how to find the vDSO expects 23153dc33bd3SKees Cook to be able to issue three syscalls by calling fixed addresses in 23163dc33bd3SKees Cook kernel space. Since this location is not randomized with ASLR, 23173dc33bd3SKees Cook it can be used to assist security vulnerability exploitation. 23183dc33bd3SKees Cook 23193dc33bd3SKees Cook This setting can be changed at boot time via the kernel command 2320bd49e16eSAndy Lutomirski line parameter vsyscall=[emulate|xonly|none]. 23213dc33bd3SKees Cook 23223dc33bd3SKees Cook On a system with recent enough glibc (2.14 or newer) and no 23233dc33bd3SKees Cook static binaries, you can say None without a performance penalty 23243dc33bd3SKees Cook to improve security. 23253dc33bd3SKees Cook 2326bd49e16eSAndy Lutomirski If unsure, select "Emulate execution only". 23273dc33bd3SKees Cook 23283dc33bd3SKees Cook config LEGACY_VSYSCALL_EMULATE 2329bd49e16eSAndy Lutomirski bool "Full emulation" 23303dc33bd3SKees Cook help 2331bd49e16eSAndy Lutomirski The kernel traps and emulates calls into the fixed vsyscall 2332bd49e16eSAndy Lutomirski address mapping. This makes the mapping non-executable, but 2333bd49e16eSAndy Lutomirski it still contains readable known contents, which could be 2334bd49e16eSAndy Lutomirski used in certain rare security vulnerability exploits. This 2335bd49e16eSAndy Lutomirski configuration is recommended when using legacy userspace 2336bd49e16eSAndy Lutomirski that still uses vsyscalls along with legacy binary 2337bd49e16eSAndy Lutomirski instrumentation tools that require code to be readable. 2338bd49e16eSAndy Lutomirski 2339bd49e16eSAndy Lutomirski An example of this type of legacy userspace is running 2340bd49e16eSAndy Lutomirski Pin on an old binary that still uses vsyscalls. 2341bd49e16eSAndy Lutomirski 2342bd49e16eSAndy Lutomirski config LEGACY_VSYSCALL_XONLY 2343bd49e16eSAndy Lutomirski bool "Emulate execution only" 2344bd49e16eSAndy Lutomirski help 2345bd49e16eSAndy Lutomirski The kernel traps and emulates calls into the fixed vsyscall 2346bd49e16eSAndy Lutomirski address mapping and does not allow reads. This 2347bd49e16eSAndy Lutomirski configuration is recommended when userspace might use the 2348bd49e16eSAndy Lutomirski legacy vsyscall area but support for legacy binary 2349bd49e16eSAndy Lutomirski instrumentation of legacy code is not needed. It mitigates 2350bd49e16eSAndy Lutomirski certain uses of the vsyscall area as an ASLR-bypassing 2351bd49e16eSAndy Lutomirski buffer. 23523dc33bd3SKees Cook 23533dc33bd3SKees Cook config LEGACY_VSYSCALL_NONE 23543dc33bd3SKees Cook bool "None" 23553dc33bd3SKees Cook help 23563dc33bd3SKees Cook There will be no vsyscall mapping at all. This will 23573dc33bd3SKees Cook eliminate any risk of ASLR bypass due to the vsyscall 23583dc33bd3SKees Cook fixed address mapping. Attempts to use the vsyscalls 23593dc33bd3SKees Cook will be reported to dmesg, so that either old or 23603dc33bd3SKees Cook malicious userspace programs can be identified. 23613dc33bd3SKees Cook 23623dc33bd3SKees Cookendchoice 23633dc33bd3SKees Cook 2364516cbf37STim Birdconfig CMDLINE_BOOL 2365516cbf37STim Bird bool "Built-in kernel command line" 2366a7f7f624SMasahiro Yamada help 2367516cbf37STim Bird Allow for specifying boot arguments to the kernel at 2368516cbf37STim Bird build time. On some systems (e.g. embedded ones), it is 2369516cbf37STim Bird necessary or convenient to provide some or all of the 2370516cbf37STim Bird kernel boot arguments with the kernel itself (that is, 2371516cbf37STim Bird to not rely on the boot loader to provide them.) 2372516cbf37STim Bird 2373516cbf37STim Bird To compile command line arguments into the kernel, 2374516cbf37STim Bird set this option to 'Y', then fill in the 237569711ca1SSébastien Hinderer boot arguments in CONFIG_CMDLINE. 2376516cbf37STim Bird 2377516cbf37STim Bird Systems with fully functional boot loaders (i.e. non-embedded) 2378516cbf37STim Bird should leave this option set to 'N'. 2379516cbf37STim Bird 2380516cbf37STim Birdconfig CMDLINE 2381516cbf37STim Bird string "Built-in kernel command string" 2382516cbf37STim Bird depends on CMDLINE_BOOL 2383516cbf37STim Bird default "" 2384a7f7f624SMasahiro Yamada help 2385516cbf37STim Bird Enter arguments here that should be compiled into the kernel 2386516cbf37STim Bird image and used at boot time. If the boot loader provides a 2387516cbf37STim Bird command line at boot time, it is appended to this string to 2388516cbf37STim Bird form the full kernel command line, when the system boots. 2389516cbf37STim Bird 2390516cbf37STim Bird However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2391516cbf37STim Bird change this behavior. 2392516cbf37STim Bird 2393516cbf37STim Bird In most cases, the command line (whether built-in or provided 2394516cbf37STim Bird by the boot loader) should specify the device for the root 2395516cbf37STim Bird file system. 2396516cbf37STim Bird 2397516cbf37STim Birdconfig CMDLINE_OVERRIDE 2398516cbf37STim Bird bool "Built-in command line overrides boot loader arguments" 2399645e6466SAnders Roxell depends on CMDLINE_BOOL && CMDLINE != "" 2400a7f7f624SMasahiro Yamada help 2401516cbf37STim Bird Set this option to 'Y' to have the kernel ignore the boot loader 2402516cbf37STim Bird command line, and use ONLY the built-in command line. 2403516cbf37STim Bird 2404516cbf37STim Bird This is used to work around broken boot loaders. This should 2405516cbf37STim Bird be set to 'N' under normal conditions. 2406516cbf37STim Bird 2407a5b9e5a2SAndy Lutomirskiconfig MODIFY_LDT_SYSCALL 2408a5b9e5a2SAndy Lutomirski bool "Enable the LDT (local descriptor table)" if EXPERT 2409a5b9e5a2SAndy Lutomirski default y 2410a7f7f624SMasahiro Yamada help 2411a5b9e5a2SAndy Lutomirski Linux can allow user programs to install a per-process x86 2412a5b9e5a2SAndy Lutomirski Local Descriptor Table (LDT) using the modify_ldt(2) system 2413a5b9e5a2SAndy Lutomirski call. This is required to run 16-bit or segmented code such as 2414a5b9e5a2SAndy Lutomirski DOSEMU or some Wine programs. It is also used by some very old 2415a5b9e5a2SAndy Lutomirski threading libraries. 2416a5b9e5a2SAndy Lutomirski 2417a5b9e5a2SAndy Lutomirski Enabling this feature adds a small amount of overhead to 2418a5b9e5a2SAndy Lutomirski context switches and increases the low-level kernel attack 2419a5b9e5a2SAndy Lutomirski surface. Disabling it removes the modify_ldt(2) system call. 2420a5b9e5a2SAndy Lutomirski 2421a5b9e5a2SAndy Lutomirski Saying 'N' here may make sense for embedded or server kernels. 2422a5b9e5a2SAndy Lutomirski 2423b700e7f0SSeth Jenningssource "kernel/livepatch/Kconfig" 2424b700e7f0SSeth Jennings 2425506f1d07SSam Ravnborgendmenu 2426506f1d07SSam Ravnborg 24273072e413SMichal Hockoconfig ARCH_HAS_ADD_PAGES 24283072e413SMichal Hocko def_bool y 24293072e413SMichal Hocko depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG 24303072e413SMichal Hocko 2431506f1d07SSam Ravnborgconfig ARCH_ENABLE_MEMORY_HOTPLUG 2432506f1d07SSam Ravnborg def_bool y 2433506f1d07SSam Ravnborg depends on X86_64 || (X86_32 && HIGHMEM) 2434506f1d07SSam Ravnborg 243535551053SGary Hadeconfig ARCH_ENABLE_MEMORY_HOTREMOVE 243635551053SGary Hade def_bool y 243735551053SGary Hade depends on MEMORY_HOTPLUG 243835551053SGary Hade 2439e534c7c5SLee Schermerhornconfig USE_PERCPU_NUMA_NODE_ID 2440645a7919STejun Heo def_bool y 2441e534c7c5SLee Schermerhorn depends on NUMA 2442e534c7c5SLee Schermerhorn 24439491846fSKirill A. Shutemovconfig ARCH_ENABLE_SPLIT_PMD_PTLOCK 24449491846fSKirill A. Shutemov def_bool y 24459491846fSKirill A. Shutemov depends on X86_64 || X86_PAE 24469491846fSKirill A. Shutemov 2447c177c81eSNaoya Horiguchiconfig ARCH_ENABLE_HUGEPAGE_MIGRATION 2448c177c81eSNaoya Horiguchi def_bool y 2449c177c81eSNaoya Horiguchi depends on X86_64 && HUGETLB_PAGE && MIGRATION 2450c177c81eSNaoya Horiguchi 24519c670ea3SNaoya Horiguchiconfig ARCH_ENABLE_THP_MIGRATION 24529c670ea3SNaoya Horiguchi def_bool y 24539c670ea3SNaoya Horiguchi depends on X86_64 && TRANSPARENT_HUGEPAGE 24549c670ea3SNaoya Horiguchi 2455da85f865SBjorn Helgaasmenu "Power management and ACPI options" 2456e279b6c1SSam Ravnborg 2457e279b6c1SSam Ravnborgconfig ARCH_HIBERNATION_HEADER 24583c2362e6SHarvey Harrison def_bool y 245944556530SZhimin Gu depends on HIBERNATION 2460e279b6c1SSam Ravnborg 2461e279b6c1SSam Ravnborgsource "kernel/power/Kconfig" 2462e279b6c1SSam Ravnborg 2463e279b6c1SSam Ravnborgsource "drivers/acpi/Kconfig" 2464e279b6c1SSam Ravnborg 2465efafc8b2SFeng Tangsource "drivers/sfi/Kconfig" 2466efafc8b2SFeng Tang 2467a6b68076SAndi Kleenconfig X86_APM_BOOT 24686fc108a0SJan Beulich def_bool y 2469282e5aabSPaul Bolle depends on APM 2470a6b68076SAndi Kleen 2471e279b6c1SSam Ravnborgmenuconfig APM 2472e279b6c1SSam Ravnborg tristate "APM (Advanced Power Management) BIOS support" 2473efefa6f6SIngo Molnar depends on X86_32 && PM_SLEEP 2474a7f7f624SMasahiro Yamada help 2475e279b6c1SSam Ravnborg APM is a BIOS specification for saving power using several different 2476e279b6c1SSam Ravnborg techniques. This is mostly useful for battery powered laptops with 2477e279b6c1SSam Ravnborg APM compliant BIOSes. If you say Y here, the system time will be 2478e279b6c1SSam Ravnborg reset after a RESUME operation, the /proc/apm device will provide 2479e279b6c1SSam Ravnborg battery status information, and user-space programs will receive 2480e279b6c1SSam Ravnborg notification of APM "events" (e.g. battery status change). 2481e279b6c1SSam Ravnborg 2482e279b6c1SSam Ravnborg If you select "Y" here, you can disable actual use of the APM 2483e279b6c1SSam Ravnborg BIOS by passing the "apm=off" option to the kernel at boot time. 2484e279b6c1SSam Ravnborg 2485e279b6c1SSam Ravnborg Note that the APM support is almost completely disabled for 2486e279b6c1SSam Ravnborg machines with more than one CPU. 2487e279b6c1SSam Ravnborg 2488e279b6c1SSam Ravnborg In order to use APM, you will need supporting software. For location 2489151f4e2bSMauro Carvalho Chehab and more information, read <file:Documentation/power/apm-acpi.rst> 24902dc98fd3SMichael Witten and the Battery Powered Linux mini-HOWTO, available from 2491e279b6c1SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 2492e279b6c1SSam Ravnborg 2493e279b6c1SSam Ravnborg This driver does not spin down disk drives (see the hdparm(8) 2494e279b6c1SSam Ravnborg manpage ("man 8 hdparm") for that), and it doesn't turn off 2495e279b6c1SSam Ravnborg VESA-compliant "green" monitors. 2496e279b6c1SSam Ravnborg 2497e279b6c1SSam Ravnborg This driver does not support the TI 4000M TravelMate and the ACER 2498e279b6c1SSam Ravnborg 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2499e279b6c1SSam Ravnborg desktop machines also don't have compliant BIOSes, and this driver 2500e279b6c1SSam Ravnborg may cause those machines to panic during the boot phase. 2501e279b6c1SSam Ravnborg 2502e279b6c1SSam Ravnborg Generally, if you don't have a battery in your machine, there isn't 2503e279b6c1SSam Ravnborg much point in using this driver and you should say N. If you get 2504e279b6c1SSam Ravnborg random kernel OOPSes or reboots that don't seem to be related to 2505e279b6c1SSam Ravnborg anything, try disabling/enabling this option (or disabling/enabling 2506e279b6c1SSam Ravnborg APM in your BIOS). 2507e279b6c1SSam Ravnborg 2508e279b6c1SSam Ravnborg Some other things you should try when experiencing seemingly random, 2509e279b6c1SSam Ravnborg "weird" problems: 2510e279b6c1SSam Ravnborg 2511e279b6c1SSam Ravnborg 1) make sure that you have enough swap space and that it is 2512e279b6c1SSam Ravnborg enabled. 2513e279b6c1SSam Ravnborg 2) pass the "no-hlt" option to the kernel 2514e279b6c1SSam Ravnborg 3) switch on floating point emulation in the kernel and pass 2515e279b6c1SSam Ravnborg the "no387" option to the kernel 2516e279b6c1SSam Ravnborg 4) pass the "floppy=nodma" option to the kernel 2517e279b6c1SSam Ravnborg 5) pass the "mem=4M" option to the kernel (thereby disabling 2518e279b6c1SSam Ravnborg all but the first 4 MB of RAM) 2519e279b6c1SSam Ravnborg 6) make sure that the CPU is not over clocked. 2520e279b6c1SSam Ravnborg 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2521e279b6c1SSam Ravnborg 8) disable the cache from your BIOS settings 2522e279b6c1SSam Ravnborg 9) install a fan for the video card or exchange video RAM 2523e279b6c1SSam Ravnborg 10) install a better fan for the CPU 2524e279b6c1SSam Ravnborg 11) exchange RAM chips 2525e279b6c1SSam Ravnborg 12) exchange the motherboard. 2526e279b6c1SSam Ravnborg 2527e279b6c1SSam Ravnborg To compile this driver as a module, choose M here: the 2528e279b6c1SSam Ravnborg module will be called apm. 2529e279b6c1SSam Ravnborg 2530e279b6c1SSam Ravnborgif APM 2531e279b6c1SSam Ravnborg 2532e279b6c1SSam Ravnborgconfig APM_IGNORE_USER_SUSPEND 2533e279b6c1SSam Ravnborg bool "Ignore USER SUSPEND" 2534a7f7f624SMasahiro Yamada help 2535e279b6c1SSam Ravnborg This option will ignore USER SUSPEND requests. On machines with a 2536e279b6c1SSam Ravnborg compliant APM BIOS, you want to say N. However, on the NEC Versa M 2537e279b6c1SSam Ravnborg series notebooks, it is necessary to say Y because of a BIOS bug. 2538e279b6c1SSam Ravnborg 2539e279b6c1SSam Ravnborgconfig APM_DO_ENABLE 2540e279b6c1SSam Ravnborg bool "Enable PM at boot time" 2541a7f7f624SMasahiro Yamada help 2542e279b6c1SSam Ravnborg Enable APM features at boot time. From page 36 of the APM BIOS 2543e279b6c1SSam Ravnborg specification: "When disabled, the APM BIOS does not automatically 2544e279b6c1SSam Ravnborg power manage devices, enter the Standby State, enter the Suspend 2545e279b6c1SSam Ravnborg State, or take power saving steps in response to CPU Idle calls." 2546e279b6c1SSam Ravnborg This driver will make CPU Idle calls when Linux is idle (unless this 2547e279b6c1SSam Ravnborg feature is turned off -- see "Do CPU IDLE calls", below). This 2548e279b6c1SSam Ravnborg should always save battery power, but more complicated APM features 2549e279b6c1SSam Ravnborg will be dependent on your BIOS implementation. You may need to turn 2550e279b6c1SSam Ravnborg this option off if your computer hangs at boot time when using APM 2551e279b6c1SSam Ravnborg support, or if it beeps continuously instead of suspending. Turn 2552e279b6c1SSam Ravnborg this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2553e279b6c1SSam Ravnborg T400CDT. This is off by default since most machines do fine without 2554e279b6c1SSam Ravnborg this feature. 2555e279b6c1SSam Ravnborg 2556e279b6c1SSam Ravnborgconfig APM_CPU_IDLE 2557dd8af076SLen Brown depends on CPU_IDLE 2558e279b6c1SSam Ravnborg bool "Make CPU Idle calls when idle" 2559a7f7f624SMasahiro Yamada help 2560e279b6c1SSam Ravnborg Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2561e279b6c1SSam Ravnborg On some machines, this can activate improved power savings, such as 2562e279b6c1SSam Ravnborg a slowed CPU clock rate, when the machine is idle. These idle calls 2563e279b6c1SSam Ravnborg are made after the idle loop has run for some length of time (e.g., 2564e279b6c1SSam Ravnborg 333 mS). On some machines, this will cause a hang at boot time or 2565e279b6c1SSam Ravnborg whenever the CPU becomes idle. (On machines with more than one CPU, 2566e279b6c1SSam Ravnborg this option does nothing.) 2567e279b6c1SSam Ravnborg 2568e279b6c1SSam Ravnborgconfig APM_DISPLAY_BLANK 2569e279b6c1SSam Ravnborg bool "Enable console blanking using APM" 2570a7f7f624SMasahiro Yamada help 2571e279b6c1SSam Ravnborg Enable console blanking using the APM. Some laptops can use this to 2572e279b6c1SSam Ravnborg turn off the LCD backlight when the screen blanker of the Linux 2573e279b6c1SSam Ravnborg virtual console blanks the screen. Note that this is only used by 2574e279b6c1SSam Ravnborg the virtual console screen blanker, and won't turn off the backlight 2575e279b6c1SSam Ravnborg when using the X Window system. This also doesn't have anything to 2576e279b6c1SSam Ravnborg do with your VESA-compliant power-saving monitor. Further, this 2577e279b6c1SSam Ravnborg option doesn't work for all laptops -- it might not turn off your 2578e279b6c1SSam Ravnborg backlight at all, or it might print a lot of errors to the console, 2579e279b6c1SSam Ravnborg especially if you are using gpm. 2580e279b6c1SSam Ravnborg 2581e279b6c1SSam Ravnborgconfig APM_ALLOW_INTS 2582e279b6c1SSam Ravnborg bool "Allow interrupts during APM BIOS calls" 2583a7f7f624SMasahiro Yamada help 2584e279b6c1SSam Ravnborg Normally we disable external interrupts while we are making calls to 2585e279b6c1SSam Ravnborg the APM BIOS as a measure to lessen the effects of a badly behaving 2586e279b6c1SSam Ravnborg BIOS implementation. The BIOS should reenable interrupts if it 2587e279b6c1SSam Ravnborg needs to. Unfortunately, some BIOSes do not -- especially those in 2588e279b6c1SSam Ravnborg many of the newer IBM Thinkpads. If you experience hangs when you 2589e279b6c1SSam Ravnborg suspend, try setting this to Y. Otherwise, say N. 2590e279b6c1SSam Ravnborg 2591e279b6c1SSam Ravnborgendif # APM 2592e279b6c1SSam Ravnborg 2593bb0a56ecSDave Jonessource "drivers/cpufreq/Kconfig" 2594e279b6c1SSam Ravnborg 2595e279b6c1SSam Ravnborgsource "drivers/cpuidle/Kconfig" 2596e279b6c1SSam Ravnborg 259727471fdbSAndy Henroidsource "drivers/idle/Kconfig" 259827471fdbSAndy Henroid 2599e279b6c1SSam Ravnborgendmenu 2600e279b6c1SSam Ravnborg 2601e279b6c1SSam Ravnborg 2602e279b6c1SSam Ravnborgmenu "Bus options (PCI etc.)" 2603e279b6c1SSam Ravnborg 2604e279b6c1SSam Ravnborgchoice 2605e279b6c1SSam Ravnborg prompt "PCI access mode" 2606efefa6f6SIngo Molnar depends on X86_32 && PCI 2607e279b6c1SSam Ravnborg default PCI_GOANY 2608a7f7f624SMasahiro Yamada help 2609e279b6c1SSam Ravnborg On PCI systems, the BIOS can be used to detect the PCI devices and 2610e279b6c1SSam Ravnborg determine their configuration. However, some old PCI motherboards 2611e279b6c1SSam Ravnborg have BIOS bugs and may crash if this is done. Also, some embedded 2612e279b6c1SSam Ravnborg PCI-based systems don't have any BIOS at all. Linux can also try to 2613e279b6c1SSam Ravnborg detect the PCI hardware directly without using the BIOS. 2614e279b6c1SSam Ravnborg 2615e279b6c1SSam Ravnborg With this option, you can specify how Linux should detect the 2616e279b6c1SSam Ravnborg PCI devices. If you choose "BIOS", the BIOS will be used, 2617e279b6c1SSam Ravnborg if you choose "Direct", the BIOS won't be used, and if you 2618e279b6c1SSam Ravnborg choose "MMConfig", then PCI Express MMCONFIG will be used. 2619e279b6c1SSam Ravnborg If you choose "Any", the kernel will try MMCONFIG, then the 2620e279b6c1SSam Ravnborg direct access method and falls back to the BIOS if that doesn't 2621e279b6c1SSam Ravnborg work. If unsure, go with the default, which is "Any". 2622e279b6c1SSam Ravnborg 2623e279b6c1SSam Ravnborgconfig PCI_GOBIOS 2624e279b6c1SSam Ravnborg bool "BIOS" 2625e279b6c1SSam Ravnborg 2626e279b6c1SSam Ravnborgconfig PCI_GOMMCONFIG 2627e279b6c1SSam Ravnborg bool "MMConfig" 2628e279b6c1SSam Ravnborg 2629e279b6c1SSam Ravnborgconfig PCI_GODIRECT 2630e279b6c1SSam Ravnborg bool "Direct" 2631e279b6c1SSam Ravnborg 26323ef0e1f8SAndres Salomonconfig PCI_GOOLPC 263376fb6570SDaniel Drake bool "OLPC XO-1" 26343ef0e1f8SAndres Salomon depends on OLPC 26353ef0e1f8SAndres Salomon 26362bdd1b03SAndres Salomonconfig PCI_GOANY 26372bdd1b03SAndres Salomon bool "Any" 26382bdd1b03SAndres Salomon 2639e279b6c1SSam Ravnborgendchoice 2640e279b6c1SSam Ravnborg 2641e279b6c1SSam Ravnborgconfig PCI_BIOS 26423c2362e6SHarvey Harrison def_bool y 2643efefa6f6SIngo Molnar depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2644e279b6c1SSam Ravnborg 2645e279b6c1SSam Ravnborg# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2646e279b6c1SSam Ravnborgconfig PCI_DIRECT 26473c2362e6SHarvey Harrison def_bool y 26480aba496fSShaohua Li depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2649e279b6c1SSam Ravnborg 2650e279b6c1SSam Ravnborgconfig PCI_MMCONFIG 2651b45c9f36SJan Kiszka bool "Support mmconfig PCI config space access" if X86_64 2652b45c9f36SJan Kiszka default y 26538364e1f8SJan Kiszka depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST) 2654b45c9f36SJan Kiszka depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2655e279b6c1SSam Ravnborg 26563ef0e1f8SAndres Salomonconfig PCI_OLPC 26572bdd1b03SAndres Salomon def_bool y 26582bdd1b03SAndres Salomon depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 26593ef0e1f8SAndres Salomon 2660b5401a96SAlex Nixonconfig PCI_XEN 2661b5401a96SAlex Nixon def_bool y 2662b5401a96SAlex Nixon depends on PCI && XEN 2663b5401a96SAlex Nixon select SWIOTLB_XEN 2664b5401a96SAlex Nixon 26658364e1f8SJan Kiszkaconfig MMCONF_FAM10H 26668364e1f8SJan Kiszka def_bool y 26678364e1f8SJan Kiszka depends on X86_64 && PCI_MMCONFIG && ACPI 2668e279b6c1SSam Ravnborg 26693f6ea84aSIra W. Snyderconfig PCI_CNB20LE_QUIRK 26706a108a14SDavid Rientjes bool "Read CNB20LE Host Bridge Windows" if EXPERT 26716ea30386SKees Cook depends on PCI 26723f6ea84aSIra W. Snyder help 26733f6ea84aSIra W. Snyder Read the PCI windows out of the CNB20LE host bridge. This allows 26743f6ea84aSIra W. Snyder PCI hotplug to work on systems with the CNB20LE chipset which do 26753f6ea84aSIra W. Snyder not have ACPI. 26763f6ea84aSIra W. Snyder 267764a5fed6SBjorn Helgaas There's no public spec for this chipset, and this functionality 267864a5fed6SBjorn Helgaas is known to be incomplete. 267964a5fed6SBjorn Helgaas 268064a5fed6SBjorn Helgaas You should say N unless you know you need this. 268164a5fed6SBjorn Helgaas 26823a495511SWilliam Breathitt Grayconfig ISA_BUS 268317a2a129SWilliam Breathitt Gray bool "ISA bus support on modern systems" if EXPERT 26843a495511SWilliam Breathitt Gray help 268517a2a129SWilliam Breathitt Gray Expose ISA bus device drivers and options available for selection and 268617a2a129SWilliam Breathitt Gray configuration. Enable this option if your target machine has an ISA 268717a2a129SWilliam Breathitt Gray bus. ISA is an older system, displaced by PCI and newer bus 268817a2a129SWilliam Breathitt Gray architectures -- if your target machine is modern, it probably does 268917a2a129SWilliam Breathitt Gray not have an ISA bus. 26903a495511SWilliam Breathitt Gray 26913a495511SWilliam Breathitt Gray If unsure, say N. 26923a495511SWilliam Breathitt Gray 26931c00f016SDavid Rientjes# x86_64 have no ISA slots, but can have ISA-style DMA. 2694e279b6c1SSam Ravnborgconfig ISA_DMA_API 26951c00f016SDavid Rientjes bool "ISA-style DMA support" if (X86_64 && EXPERT) 26961c00f016SDavid Rientjes default y 26971c00f016SDavid Rientjes help 26981c00f016SDavid Rientjes Enables ISA-style DMA support for devices requiring such controllers. 26991c00f016SDavid Rientjes If unsure, say Y. 2700e279b6c1SSam Ravnborg 270151e68d05SLinus Torvaldsif X86_32 270251e68d05SLinus Torvalds 2703e279b6c1SSam Ravnborgconfig ISA 2704e279b6c1SSam Ravnborg bool "ISA support" 2705a7f7f624SMasahiro Yamada help 2706e279b6c1SSam Ravnborg Find out whether you have ISA slots on your motherboard. ISA is the 2707e279b6c1SSam Ravnborg name of a bus system, i.e. the way the CPU talks to the other stuff 2708e279b6c1SSam Ravnborg inside your box. Other bus systems are PCI, EISA, MicroChannel 2709e279b6c1SSam Ravnborg (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2710e279b6c1SSam Ravnborg newer boards don't support it. If you have ISA, say Y, otherwise N. 2711e279b6c1SSam Ravnborg 2712e279b6c1SSam Ravnborgconfig SCx200 2713e279b6c1SSam Ravnborg tristate "NatSemi SCx200 support" 2714a7f7f624SMasahiro Yamada help 2715e279b6c1SSam Ravnborg This provides basic support for National Semiconductor's 2716e279b6c1SSam Ravnborg (now AMD's) Geode processors. The driver probes for the 2717e279b6c1SSam Ravnborg PCI-IDs of several on-chip devices, so its a good dependency 2718e279b6c1SSam Ravnborg for other scx200_* drivers. 2719e279b6c1SSam Ravnborg 2720e279b6c1SSam Ravnborg If compiled as a module, the driver is named scx200. 2721e279b6c1SSam Ravnborg 2722e279b6c1SSam Ravnborgconfig SCx200HR_TIMER 2723e279b6c1SSam Ravnborg tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2724592913ecSJohn Stultz depends on SCx200 2725e279b6c1SSam Ravnborg default y 2726a7f7f624SMasahiro Yamada help 2727e279b6c1SSam Ravnborg This driver provides a clocksource built upon the on-chip 2728e279b6c1SSam Ravnborg 27MHz high-resolution timer. Its also a workaround for 2729e279b6c1SSam Ravnborg NSC Geode SC-1100's buggy TSC, which loses time when the 2730e279b6c1SSam Ravnborg processor goes idle (as is done by the scheduler). The 2731e279b6c1SSam Ravnborg other workaround is idle=poll boot option. 2732e279b6c1SSam Ravnborg 27333ef0e1f8SAndres Salomonconfig OLPC 27343ef0e1f8SAndres Salomon bool "One Laptop Per Child support" 273554008979SThomas Gleixner depends on !X86_PAE 27363c554946SAndres Salomon select GPIOLIB 2737dc3119e7SThomas Gleixner select OF 273845bb1674SDaniel Drake select OF_PROMTREE 2739b4e51854SGrant Likely select IRQ_DOMAIN 27400c3d931bSLubomir Rintel select OLPC_EC 2741a7f7f624SMasahiro Yamada help 27423ef0e1f8SAndres Salomon Add support for detecting the unique features of the OLPC 27433ef0e1f8SAndres Salomon XO hardware. 27443ef0e1f8SAndres Salomon 2745a3128588SDaniel Drakeconfig OLPC_XO1_PM 2746a3128588SDaniel Drake bool "OLPC XO-1 Power Management" 2747fa112cf1SBorislav Petkov depends on OLPC && MFD_CS5535=y && PM_SLEEP 2748a7f7f624SMasahiro Yamada help 274997c4cb71SDaniel Drake Add support for poweroff and suspend of the OLPC XO-1 laptop. 2750bf1ebf00SDaniel Drake 2751cfee9597SDaniel Drakeconfig OLPC_XO1_RTC 2752cfee9597SDaniel Drake bool "OLPC XO-1 Real Time Clock" 2753cfee9597SDaniel Drake depends on OLPC_XO1_PM && RTC_DRV_CMOS 2754a7f7f624SMasahiro Yamada help 2755cfee9597SDaniel Drake Add support for the XO-1 real time clock, which can be used as a 2756cfee9597SDaniel Drake programmable wakeup source. 2757cfee9597SDaniel Drake 27587feda8e9SDaniel Drakeconfig OLPC_XO1_SCI 27597feda8e9SDaniel Drake bool "OLPC XO-1 SCI extras" 276092e830f2SArnd Bergmann depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2761ed8e47feSRandy Dunlap depends on INPUT=y 2762d8d01a63SDaniel Drake select POWER_SUPPLY 2763a7f7f624SMasahiro Yamada help 27647feda8e9SDaniel Drake Add support for SCI-based features of the OLPC XO-1 laptop: 27657bc74b3dSDaniel Drake - EC-driven system wakeups 27667feda8e9SDaniel Drake - Power button 27677bc74b3dSDaniel Drake - Ebook switch 27682cf2baeaSDaniel Drake - Lid switch 2769e1040ac6SDaniel Drake - AC adapter status updates 2770e1040ac6SDaniel Drake - Battery status updates 27717feda8e9SDaniel Drake 2772a0f30f59SDaniel Drakeconfig OLPC_XO15_SCI 2773a0f30f59SDaniel Drake bool "OLPC XO-1.5 SCI extras" 2774d8d01a63SDaniel Drake depends on OLPC && ACPI 2775d8d01a63SDaniel Drake select POWER_SUPPLY 2776a7f7f624SMasahiro Yamada help 2777a0f30f59SDaniel Drake Add support for SCI-based features of the OLPC XO-1.5 laptop: 2778a0f30f59SDaniel Drake - EC-driven system wakeups 2779a0f30f59SDaniel Drake - AC adapter status updates 2780a0f30f59SDaniel Drake - Battery status updates 2781e279b6c1SSam Ravnborg 2782d4f3e350SEd Wildgooseconfig ALIX 2783d4f3e350SEd Wildgoose bool "PCEngines ALIX System Support (LED setup)" 2784d4f3e350SEd Wildgoose select GPIOLIB 2785a7f7f624SMasahiro Yamada help 2786d4f3e350SEd Wildgoose This option enables system support for the PCEngines ALIX. 2787d4f3e350SEd Wildgoose At present this just sets up LEDs for GPIO control on 2788d4f3e350SEd Wildgoose ALIX2/3/6 boards. However, other system specific setup should 2789d4f3e350SEd Wildgoose get added here. 2790d4f3e350SEd Wildgoose 2791d4f3e350SEd Wildgoose Note: You must still enable the drivers for GPIO and LED support 2792d4f3e350SEd Wildgoose (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2793d4f3e350SEd Wildgoose 2794d4f3e350SEd Wildgoose Note: You have to set alix.force=1 for boards with Award BIOS. 2795d4f3e350SEd Wildgoose 2796da4e3302SPhilip Prindevilleconfig NET5501 2797da4e3302SPhilip Prindeville bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2798da4e3302SPhilip Prindeville select GPIOLIB 2799a7f7f624SMasahiro Yamada help 2800da4e3302SPhilip Prindeville This option enables system support for the Soekris Engineering net5501. 2801da4e3302SPhilip Prindeville 28023197059aSPhilip A. Prindevilleconfig GEOS 28033197059aSPhilip A. Prindeville bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 28043197059aSPhilip A. Prindeville select GPIOLIB 28053197059aSPhilip A. Prindeville depends on DMI 2806a7f7f624SMasahiro Yamada help 28073197059aSPhilip A. Prindeville This option enables system support for the Traverse Technologies GEOS. 28083197059aSPhilip A. Prindeville 28097d029125SVivien Didelotconfig TS5500 28107d029125SVivien Didelot bool "Technologic Systems TS-5500 platform support" 28117d029125SVivien Didelot depends on MELAN 28127d029125SVivien Didelot select CHECK_SIGNATURE 28137d029125SVivien Didelot select NEW_LEDS 28147d029125SVivien Didelot select LEDS_CLASS 2815a7f7f624SMasahiro Yamada help 28167d029125SVivien Didelot This option enables system support for the Technologic Systems TS-5500. 28177d029125SVivien Didelot 2818e279b6c1SSam Ravnborgendif # X86_32 2819e279b6c1SSam Ravnborg 282023ac4ae8SAndreas Herrmannconfig AMD_NB 2821e279b6c1SSam Ravnborg def_bool y 28220e152cd7SBorislav Petkov depends on CPU_SUP_AMD && PCI 2823e279b6c1SSam Ravnborg 2824e3263ab3SDavid Herrmannconfig X86_SYSFB 2825e3263ab3SDavid Herrmann bool "Mark VGA/VBE/EFI FB as generic system framebuffer" 2826e3263ab3SDavid Herrmann help 2827e3263ab3SDavid Herrmann Firmwares often provide initial graphics framebuffers so the BIOS, 2828e3263ab3SDavid Herrmann bootloader or kernel can show basic video-output during boot for 2829e3263ab3SDavid Herrmann user-guidance and debugging. Historically, x86 used the VESA BIOS 2830e3263ab3SDavid Herrmann Extensions and EFI-framebuffers for this, which are mostly limited 2831e3263ab3SDavid Herrmann to x86. 2832e3263ab3SDavid Herrmann This option, if enabled, marks VGA/VBE/EFI framebuffers as generic 2833e3263ab3SDavid Herrmann framebuffers so the new generic system-framebuffer drivers can be 2834e3263ab3SDavid Herrmann used on x86. If the framebuffer is not compatible with the generic 2835e3a5dc08SNikolas Nyby modes, it is advertised as fallback platform framebuffer so legacy 2836e3263ab3SDavid Herrmann drivers like efifb, vesafb and uvesafb can pick it up. 2837e3263ab3SDavid Herrmann If this option is not selected, all system framebuffers are always 2838e3263ab3SDavid Herrmann marked as fallback platform framebuffers as usual. 2839e3263ab3SDavid Herrmann 2840e3263ab3SDavid Herrmann Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will 2841e3263ab3SDavid Herrmann not be able to pick up generic system framebuffers if this option 2842e3263ab3SDavid Herrmann is selected. You are highly encouraged to enable simplefb as 2843e3263ab3SDavid Herrmann replacement if you select this option. simplefb can correctly deal 2844e3263ab3SDavid Herrmann with generic system framebuffers. But you should still keep vesafb 2845e3263ab3SDavid Herrmann and others enabled as fallback if a system framebuffer is 2846e3263ab3SDavid Herrmann incompatible with simplefb. 2847e3263ab3SDavid Herrmann 2848e3263ab3SDavid Herrmann If unsure, say Y. 2849e3263ab3SDavid Herrmann 2850e279b6c1SSam Ravnborgendmenu 2851e279b6c1SSam Ravnborg 2852e279b6c1SSam Ravnborg 28531572497cSChristoph Hellwigmenu "Binary Emulations" 2854e279b6c1SSam Ravnborg 2855e279b6c1SSam Ravnborgconfig IA32_EMULATION 2856e279b6c1SSam Ravnborg bool "IA32 Emulation" 2857e279b6c1SSam Ravnborg depends on X86_64 285839f88911SIngo Molnar select ARCH_WANT_OLD_COMPAT_IPC 2859d1603990SRandy Dunlap select BINFMT_ELF 2860a97f52e6SRoland McGrath select COMPAT_BINFMT_ELF 286139f88911SIngo Molnar select COMPAT_OLD_SIGACTION 2862a7f7f624SMasahiro Yamada help 28635fd92e65SH. J. Lu Include code to run legacy 32-bit programs under a 28645fd92e65SH. J. Lu 64-bit kernel. You should likely turn this on, unless you're 28655fd92e65SH. J. Lu 100% sure that you don't have any 32-bit programs left. 2866e279b6c1SSam Ravnborg 2867e279b6c1SSam Ravnborgconfig IA32_AOUT 2868e279b6c1SSam Ravnborg tristate "IA32 a.out support" 28696b213e1bSDavid Woodhouse depends on IA32_EMULATION 2870eac61655SBorislav Petkov depends on BROKEN 2871a7f7f624SMasahiro Yamada help 2872e279b6c1SSam Ravnborg Support old a.out binaries in the 32bit emulation. 2873e279b6c1SSam Ravnborg 28740bf62763SH. Peter Anvinconfig X86_X32 28756ea30386SKees Cook bool "x32 ABI for 64-bit mode" 28769b54050bSBrian Gerst depends on X86_64 2877a7f7f624SMasahiro Yamada help 28785fd92e65SH. J. Lu Include code to run binaries for the x32 native 32-bit ABI 28795fd92e65SH. J. Lu for 64-bit processors. An x32 process gets access to the 28805fd92e65SH. J. Lu full 64-bit register file and wide data path while leaving 28815fd92e65SH. J. Lu pointers at 32 bits for smaller memory footprint. 28825fd92e65SH. J. Lu 28835fd92e65SH. J. Lu You will need a recent binutils (2.22 or later) with 28845fd92e65SH. J. Lu elf32_x86_64 support enabled to compile a kernel with this 28855fd92e65SH. J. Lu option set. 28865fd92e65SH. J. Lu 2887953fee1dSIngo Molnarconfig COMPAT_32 2888953fee1dSIngo Molnar def_bool y 2889953fee1dSIngo Molnar depends on IA32_EMULATION || X86_32 2890953fee1dSIngo Molnar select HAVE_UID16 2891953fee1dSIngo Molnar select OLD_SIGSUSPEND3 2892953fee1dSIngo Molnar 2893e279b6c1SSam Ravnborgconfig COMPAT 28943c2362e6SHarvey Harrison def_bool y 28950bf62763SH. Peter Anvin depends on IA32_EMULATION || X86_X32 2896e279b6c1SSam Ravnborg 28973120e25eSJan Beulichif COMPAT 2898e279b6c1SSam Ravnborgconfig COMPAT_FOR_U64_ALIGNMENT 28993120e25eSJan Beulich def_bool y 2900e279b6c1SSam Ravnborg 2901e279b6c1SSam Ravnborgconfig SYSVIPC_COMPAT 29023c2362e6SHarvey Harrison def_bool y 29033120e25eSJan Beulich depends on SYSVIPC 29043120e25eSJan Beulichendif 2905ee009e4aSDavid Howells 2906e279b6c1SSam Ravnborgendmenu 2907e279b6c1SSam Ravnborg 2908e279b6c1SSam Ravnborg 2909e5beae16SKeith Packardconfig HAVE_ATOMIC_IOMAP 2910e5beae16SKeith Packard def_bool y 2911e5beae16SKeith Packard depends on X86_32 2912e5beae16SKeith Packard 2913e279b6c1SSam Ravnborgsource "drivers/firmware/Kconfig" 2914e279b6c1SSam Ravnborg 2915edf88417SAvi Kivitysource "arch/x86/kvm/Kconfig" 29165e8ebd84SJason A. Donenfeld 29175e8ebd84SJason A. Donenfeldsource "arch/x86/Kconfig.assembler" 2918