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 17157e118bSThomas Gleixner select GENERIC_VDSO_32 18117ed454SThomas Gleixner select HAVE_DEBUG_STACKOVERFLOW 19157e118bSThomas Gleixner select KMAP_LOCAL 20341c787eSIngo Molnar select MODULES_USE_ELF_REL 21341c787eSIngo Molnar select OLD_SIGACTION 222ca408d9SBrian Gerst select ARCH_SPLIT_ARG64 23daa93fabSSam Ravnborg 24daa93fabSSam Ravnborgconfig X86_64 253120e25eSJan Beulich def_bool y 263120e25eSJan Beulich depends on 64BIT 27d94e0685SIngo Molnar # Options that are inherently 64-bit kernel only: 284eb0716eSAlexandre Ghiti select ARCH_HAS_GIGANTIC_PAGE 29c12d3362SArd Biesheuvel select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 300bff0aaeSSuren Baghdasaryan select ARCH_SUPPORTS_PER_VMA_LOCK 31d94e0685SIngo Molnar select ARCH_USE_CMPXCHG_LOCKREF 32d94e0685SIngo Molnar select HAVE_ARCH_SOFT_DIRTY 33d94e0685SIngo Molnar select MODULES_USE_ELF_RELA 34f616ab59SChristoph Hellwig select NEED_DMA_MAP_STATE 3509230cbcSChristoph Hellwig select SWIOTLB 367facdc42SAl Viro select ARCH_HAS_ELFCORE_COMPAT 3763703f37SKefeng Wang select ZONE_DMA32 381032c0baSSam Ravnborg 39518049d9SSteven Rostedt (VMware)config FORCE_DYNAMIC_FTRACE 40518049d9SSteven Rostedt (VMware) def_bool y 41518049d9SSteven Rostedt (VMware) depends on X86_32 42518049d9SSteven Rostedt (VMware) depends on FUNCTION_TRACER 43518049d9SSteven Rostedt (VMware) select DYNAMIC_FTRACE 44518049d9SSteven Rostedt (VMware) help 45518049d9SSteven Rostedt (VMware) We keep the static function tracing (!DYNAMIC_FTRACE) around 46518049d9SSteven Rostedt (VMware) in order to test the non static function tracing in the 47518049d9SSteven Rostedt (VMware) generic code, as other architectures still use it. But we 48518049d9SSteven Rostedt (VMware) only need to keep it around for x86_64. No need to keep it 49518049d9SSteven Rostedt (VMware) for x86_32. For x86_32, force DYNAMIC_FTRACE. 50d94e0685SIngo Molnar# 51d94e0685SIngo Molnar# Arch settings 52d94e0685SIngo Molnar# 53d94e0685SIngo Molnar# ( Note that options that are marked 'if X86_64' could in principle be 54d94e0685SIngo Molnar# ported to 32-bit as well. ) 55d94e0685SIngo Molnar# 568d5fffb9SSam Ravnborgconfig X86 573c2362e6SHarvey Harrison def_bool y 58c763ea26SIngo Molnar # 59c763ea26SIngo Molnar # Note: keep this list sorted alphabetically 60c763ea26SIngo Molnar # 616471b825SIngo Molnar select ACPI_LEGACY_TABLES_LOOKUP if ACPI 626e0a0ea1SGraeme Gregory select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 63942fa985SYury Norov select ARCH_32BIT_OFF_T if X86_32 642a21ad57SThomas Gleixner select ARCH_CLOCKSOURCE_INIT 658292f4f8SSean Christopherson select ARCH_CONFIGURES_CPU_MITIGATIONS 661f6d3a8fSMasami Hiramatsu select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 671e866974SAnshuman Khandual select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION 685c11f00bSDavid Hildenbrand select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64 6991024b3cSAnshuman Khandual select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG 70cebc774fSAnshuman Khandual select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE) 711e866974SAnshuman Khandual select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE 7291dda51aSAleksey Makarov select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 73c2280be8SAnshuman Khandual select ARCH_HAS_CACHE_LINE_SIZE 741156b441SDavidlohr Bueso select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION 757c7077a7SThomas Gleixner select ARCH_HAS_CPU_FINALIZE_INIT 762792d84eSKees Cook select ARCH_HAS_CURRENT_STACK_POINTER 77fa5b6ec9SLaura Abbott select ARCH_HAS_DEBUG_VIRTUAL 78399145f9SAnshuman Khandual select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 7921266be9SDan Williams select ARCH_HAS_DEVMEM_IS_ALLOWED 80b1a57bbfSDouglas Anderson select ARCH_HAS_EARLY_DEBUG if KGDB 816471b825SIngo Molnar select ARCH_HAS_ELF_RANDOMIZE 8272d93104SLinus Torvalds select ARCH_HAS_FAST_MULTIPLIER 836974f0c4SDaniel Micay select ARCH_HAS_FORTIFY_SOURCE 84957e3facSRiku Voipio select ARCH_HAS_GCOV_PROFILE_ALL 85bece04b5SMarco Elver select ARCH_HAS_KCOV if X86_64 860c9c1d56SThiago Jung Bauermann select ARCH_HAS_MEM_ENCRYPT 8710bcc80eSMathieu Desnoyers select ARCH_HAS_MEMBARRIER_SYNC_CORE 8849f88c70SPaul E. McKenney select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS 890ebeea8cSDaniel Borkmann select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 90c763ea26SIngo Molnar select ARCH_HAS_PMEM_API if X86_64 9117596731SRobin Murphy select ARCH_HAS_PTE_DEVMAP if X86_64 923010a5eaSLaurent Dufour select ARCH_HAS_PTE_SPECIAL 93eed9a328SYu Zhao select ARCH_HAS_NONLEAF_PMD_YOUNG if PGTABLE_LEVELS > 2 940aed55afSDan Williams select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 95ec6347bbSDan Williams select ARCH_HAS_COPY_MC if X86_64 96d2852a22SDaniel Borkmann select ARCH_HAS_SET_MEMORY 97d253ca0cSRick Edgecombe select ARCH_HAS_SET_DIRECT_MAP 98ad21fc4fSLaura Abbott select ARCH_HAS_STRICT_KERNEL_RWX 99ad21fc4fSLaura Abbott select ARCH_HAS_STRICT_MODULE_RWX 100ac1ab12aSMathieu Desnoyers select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 10125c619e5SBrian Gerst select ARCH_HAS_SYSCALL_WRAPPER 102c6d30853SAndrey Ryabinin select ARCH_HAS_UBSAN_SANITIZE_ALL 1037e01ccb4SZong Li select ARCH_HAS_DEBUG_WX 10463703f37SKefeng Wang select ARCH_HAS_ZONE_DMA_SET if EXPERT 1056471b825SIngo Molnar select ARCH_HAVE_NMI_SAFE_CMPXCHG 10604d5ea46SAneesh Kumar K.V select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 1076471b825SIngo Molnar select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 10877fbbc81SMark Salter select ARCH_MIGHT_HAVE_PC_PARPORT 1095e2c18c0SMark Salter select ARCH_MIGHT_HAVE_PC_SERIO 1103599fe12SThomas Gleixner select ARCH_STACKWALK 1112c870e61SArnd Bergmann select ARCH_SUPPORTS_ACPI 1126471b825SIngo Molnar select ARCH_SUPPORTS_ATOMIC_RMW 1135d6ad668SMike Rapoport select ARCH_SUPPORTS_DEBUG_PAGEALLOC 114d283d422SPasha Tatashin select ARCH_SUPPORTS_PAGE_TABLE_CHECK if X86_64 1156471b825SIngo Molnar select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 11614df3267SThomas Gleixner select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 1173c516f89SSami Tolvanen select ARCH_SUPPORTS_CFI_CLANG if X86_64 1183c516f89SSami Tolvanen select ARCH_USES_CFI_TRAPS if X86_64 && CFI_CLANG 119583bfd48SNathan Chancellor select ARCH_SUPPORTS_LTO_CLANG 120583bfd48SNathan Chancellor select ARCH_SUPPORTS_LTO_CLANG_THIN 1216471b825SIngo Molnar select ARCH_USE_BUILTIN_BSWAP 122dce44566SAnshuman Khandual select ARCH_USE_MEMTEST 1236471b825SIngo Molnar select ARCH_USE_QUEUED_RWLOCKS 1246471b825SIngo Molnar select ARCH_USE_QUEUED_SPINLOCKS 1252ce0d7f9SMark Brown select ARCH_USE_SYM_ANNOTATIONS 126ce4a4e56SAndy Lutomirski select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 12781c22041SDaniel Borkmann select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 128c763ea26SIngo Molnar select ARCH_WANTS_DYNAMIC_TASK_STRUCT 12951c2ee6dSNick Desaulniers select ARCH_WANTS_NO_INSTR 13007431506SAnshuman Khandual select ARCH_WANT_GENERAL_HUGETLB 1313876d4a3SAlexandre Ghiti select ARCH_WANT_HUGE_PMD_SHARE 13259612b24SNathan Chancellor select ARCH_WANT_LD_ORPHAN_WARN 1330b6f1582SAneesh Kumar K.V select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP if X86_64 1340b6f1582SAneesh Kumar K.V select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP if X86_64 13538d8b4e6SHuang Ying select ARCH_WANTS_THP_SWAP if X86_64 136b5f06f64SBalbir Singh select ARCH_HAS_PARANOID_L1D_FLUSH 13710916706SShile Zhang select BUILDTIME_TABLE_SORT 1386471b825SIngo Molnar select CLKEVT_I8253 1396471b825SIngo Molnar select CLOCKSOURCE_VALIDATE_LAST_CYCLE 1406471b825SIngo Molnar select CLOCKSOURCE_WATCHDOG 1417cf8f44aSAlexander Potapenko # Word-size accesses may read uninitialized data past the trailing \0 1427cf8f44aSAlexander Potapenko # in strings and cause false KMSAN reports. 1437cf8f44aSAlexander Potapenko select DCACHE_WORD_ACCESS if !KMSAN 1443aac3ebeSThomas Gleixner select DYNAMIC_SIGFRAME 14545471cd9SLinus Torvalds select EDAC_ATOMIC_SCRUB 14645471cd9SLinus Torvalds select EDAC_SUPPORT 1476471b825SIngo Molnar select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 1486471b825SIngo Molnar select GENERIC_CLOCKEVENTS_MIN_ADJUST 1496471b825SIngo Molnar select GENERIC_CMOS_UPDATE 1506471b825SIngo Molnar select GENERIC_CPU_AUTOPROBE 15161dc0f55SThomas Gleixner select GENERIC_CPU_VULNERABILITIES 1526471b825SIngo Molnar select GENERIC_EARLY_IOREMAP 15327d6b4d1SThomas Gleixner select GENERIC_ENTRY 1546471b825SIngo Molnar select GENERIC_IOMAP 155c7d6c9ddSThomas Gleixner select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 1560fa115daSThomas Gleixner select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 157ad7a929fSThomas Gleixner select GENERIC_IRQ_MIGRATION if SMP 1586471b825SIngo Molnar select GENERIC_IRQ_PROBE 159c201c917SThomas Gleixner select GENERIC_IRQ_RESERVATION_MODE 1606471b825SIngo Molnar select GENERIC_IRQ_SHOW 1616471b825SIngo Molnar select GENERIC_PENDING_IRQ if SMP 1622ae27137SSteven Price select GENERIC_PTDUMP 1636471b825SIngo Molnar select GENERIC_SMP_IDLE_THREAD 1646471b825SIngo Molnar select GENERIC_TIME_VSYSCALL 1657ac87074SVincenzo Frascino select GENERIC_GETTIMEOFDAY 166550a77a7SDmitry Safonov select GENERIC_VDSO_TIME_NS 1676ca297d4SPeter Zijlstra select GUP_GET_PXX_LOW_HIGH if X86_PAE 16817e5888eSHans de Goede select HARDIRQS_SW_RESEND 1697edaeb68SThomas Gleixner select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 170fcbfe812SNiklas Schnelle select HAS_IOPORT 1716471b825SIngo Molnar select HAVE_ACPI_APEI if ACPI 1726471b825SIngo Molnar select HAVE_ACPI_APEI_NMI if ACPI 1736471b825SIngo Molnar select HAVE_ALIGNED_STRUCT_PAGE if SLUB 1746471b825SIngo Molnar select HAVE_ARCH_AUDITSYSCALL 1756471b825SIngo Molnar select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 176eed1fceeSSong Liu select HAVE_ARCH_HUGE_VMALLOC if X86_64 1776471b825SIngo Molnar select HAVE_ARCH_JUMP_LABEL 178b34006c4SArd Biesheuvel select HAVE_ARCH_JUMP_LABEL_RELATIVE 179d17a1d97SAndrey Ryabinin select HAVE_ARCH_KASAN if X86_64 1800609ae01SDaniel Axtens select HAVE_ARCH_KASAN_VMALLOC if X86_64 1811dc0da6eSAlexander Potapenko select HAVE_ARCH_KFENCE 1824ca8cc8dSAlexander Potapenko select HAVE_ARCH_KMSAN if X86_64 1836471b825SIngo Molnar select HAVE_ARCH_KGDB 1849e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_BITS if MMU 1859e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 1861b028f78SDmitry Safonov select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 187271ca788SArd Biesheuvel select HAVE_ARCH_PREL32_RELOCATIONS 1886471b825SIngo Molnar select HAVE_ARCH_SECCOMP_FILTER 189f7d83c1cSKees Cook select HAVE_ARCH_THREAD_STRUCT_WHITELIST 190afaef01cSAlexander Popov select HAVE_ARCH_STACKLEAK 1916471b825SIngo Molnar select HAVE_ARCH_TRACEHOOK 1926471b825SIngo Molnar select HAVE_ARCH_TRANSPARENT_HUGEPAGE 193a00cc7d9SMatthew Wilcox select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 194b64d8d1eSPeter Xu select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 1957677f7fdSAxel Rasmussen select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 196e37e43a4SAndy Lutomirski select HAVE_ARCH_VMAP_STACK if X86_64 197fe950f60SKees Cook select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 198c763ea26SIngo Molnar select HAVE_ARCH_WITHIN_STACK_FRAMES 1992ff2b7ecSMasahiro Yamada select HAVE_ASM_MODVERSIONS 2006471b825SIngo Molnar select HAVE_CMPXCHG_DOUBLE 2016471b825SIngo Molnar select HAVE_CMPXCHG_LOCAL 20224a9c541SFrederic Weisbecker select HAVE_CONTEXT_TRACKING_USER if X86_64 20324a9c541SFrederic Weisbecker select HAVE_CONTEXT_TRACKING_USER_OFFSTACK if HAVE_CONTEXT_TRACKING_USER 2046471b825SIngo Molnar select HAVE_C_RECORDMCOUNT 20503f16cd0SJosh Poimboeuf select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL 206280981d6SSathvika Vasireddy select HAVE_OBJTOOL_NOP_MCOUNT if HAVE_OBJTOOL_MCOUNT 2074ed308c4SSteven Rostedt (Google) select HAVE_BUILDTIME_MCOUNT_SORT 2086471b825SIngo Molnar select HAVE_DEBUG_KMEMLEAK 2099c5a3621SAkinobu Mita select HAVE_DMA_CONTIGUOUS 210677aa9f7SSteven Rostedt select HAVE_DYNAMIC_FTRACE 21106aeaaeaSMasami Hiramatsu select HAVE_DYNAMIC_FTRACE_WITH_REGS 21202a474caSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 213562955feSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 214c316eb44SHeiko Carstens select HAVE_SAMPLE_FTRACE_DIRECT if X86_64 215503e4510SHeiko Carstens select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64 21603f5781bSWang YanQing select HAVE_EBPF_JIT 21758340a07SJohannes Berg select HAVE_EFFICIENT_UNALIGNED_ACCESS 2186630a8e5SChristoph Hellwig select HAVE_EISA 2195f56a5dfSJiri Slaby select HAVE_EXIT_THREAD 22067a929e0SChristoph Hellwig select HAVE_FAST_GUP 221644e0e8dSSteven Rostedt (VMware) select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 2226471b825SIngo Molnar select HAVE_FTRACE_MCOUNT_RECORD 223d938ba17SDonglin Peng select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER 2244a30e4c9SSteven Rostedt (VMware) select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) 2256471b825SIngo Molnar select HAVE_FUNCTION_TRACER 2266b90bd4bSEmese Revfy select HAVE_GCC_PLUGINS 2270067f129SK.Prasad select HAVE_HW_BREAKPOINT 2286471b825SIngo Molnar select HAVE_IOREMAP_PROT 229624db9eaSThomas Gleixner select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 2306471b825SIngo Molnar select HAVE_IRQ_TIME_ACCOUNTING 2314ab7674fSJosh Poimboeuf select HAVE_JUMP_LABEL_HACK if HAVE_OBJTOOL 2326471b825SIngo Molnar select HAVE_KERNEL_BZIP2 2336471b825SIngo Molnar select HAVE_KERNEL_GZIP 2346471b825SIngo Molnar select HAVE_KERNEL_LZ4 2356471b825SIngo Molnar select HAVE_KERNEL_LZMA 2366471b825SIngo Molnar select HAVE_KERNEL_LZO 2376471b825SIngo Molnar select HAVE_KERNEL_XZ 238fb46d057SNick Terrell select HAVE_KERNEL_ZSTD 2396471b825SIngo Molnar select HAVE_KPROBES 2406471b825SIngo Molnar select HAVE_KPROBES_ON_FTRACE 241540adea3SMasami Hiramatsu select HAVE_FUNCTION_ERROR_INJECTION 2426471b825SIngo Molnar select HAVE_KRETPROBES 243f3a112c0SMasami Hiramatsu select HAVE_RETHOOK 2446471b825SIngo Molnar select HAVE_KVM 2456471b825SIngo Molnar select HAVE_LIVEPATCH if X86_64 2460102752eSFrederic Weisbecker select HAVE_MIXED_BREAKPOINTS_REGS 247ee9f8fceSJosh Poimboeuf select HAVE_MOD_ARCH_SPECIFIC 2489f132f7eSJoel Fernandes (Google) select HAVE_MOVE_PMD 249be37c98dSKalesh Singh select HAVE_MOVE_PUD 25022102f45SJosh Poimboeuf select HAVE_NOINSTR_HACK if HAVE_OBJTOOL 25142a0bb3fSPetr Mladek select HAVE_NMI 252489e355bSJosh Poimboeuf select HAVE_NOINSTR_VALIDATION if HAVE_OBJTOOL 25303f16cd0SJosh Poimboeuf select HAVE_OBJTOOL if X86_64 2546471b825SIngo Molnar select HAVE_OPTPROBES 2556471b825SIngo Molnar select HAVE_PCSPKR_PLATFORM 2566471b825SIngo Molnar select HAVE_PERF_EVENTS 257c01d4323SFrederic Weisbecker select HAVE_PERF_EVENTS_NMI 25892e5aae4SNicholas Piggin select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 259eb01d42aSChristoph Hellwig select HAVE_PCI 260c5e63197SJiri Olsa select HAVE_PERF_REGS 261c5ebcedbSJiri Olsa select HAVE_PERF_USER_STACK_DUMP 262ff2e6d72SPeter Zijlstra select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 2631e9fdf21SPeter Zijlstra select MMU_GATHER_MERGE_VMAS 26400998085SThomas Gleixner select HAVE_POSIX_CPU_TIMERS_TASK_WORK 2656471b825SIngo Molnar select HAVE_REGS_AND_STACK_ACCESS_API 26603f16cd0SJosh Poimboeuf select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC || STACK_VALIDATION 2673c88ee19SMasami Hiramatsu select HAVE_FUNCTION_ARG_ACCESS_API 2687ecd19cfSKefeng Wang select HAVE_SETUP_PER_CPU_AREA 269cd1a41ceSThomas Gleixner select HAVE_SOFTIRQ_ON_OWN_STACK 270d148eac0SMasahiro Yamada select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 27103f16cd0SJosh Poimboeuf select HAVE_STACK_VALIDATION if HAVE_OBJTOOL 272e6d6c071SJosh Poimboeuf select HAVE_STATIC_CALL 27303f16cd0SJosh Poimboeuf select HAVE_STATIC_CALL_INLINE if HAVE_OBJTOOL 27499cf983cSMark Rutland select HAVE_PREEMPT_DYNAMIC_CALL 275d6761b8fSMathieu Desnoyers select HAVE_RSEQ 27609498135SMiguel Ojeda select HAVE_RUST if X86_64 2776471b825SIngo Molnar select HAVE_SYSCALL_TRACEPOINTS 2785f3da8c0SJosh Poimboeuf select HAVE_UACCESS_VALIDATION if HAVE_OBJTOOL 2796471b825SIngo Molnar select HAVE_UNSTABLE_SCHED_CLOCK 2807c68af6eSAvi Kivity select HAVE_USER_RETURN_NOTIFIER 2817ac87074SVincenzo Frascino select HAVE_GENERIC_VDSO 2820c7ffa32SThomas Gleixner select HOTPLUG_PARALLEL if SMP && X86_64 28305736e4aSThomas Gleixner select HOTPLUG_SMT if SMP 2840c7ffa32SThomas Gleixner select HOTPLUG_SPLIT_STARTUP if SMP && X86_32 285c0185808SThomas Gleixner select IRQ_FORCED_THREADING 286c2508ec5SLinus Torvalds select LOCK_MM_AND_FIND_VMA 2877ecd19cfSKefeng Wang select NEED_PER_CPU_EMBED_FIRST_CHUNK 2887ecd19cfSKefeng Wang select NEED_PER_CPU_PAGE_FIRST_CHUNK 28986596f0aSChristoph Hellwig select NEED_SG_DMA_LENGTH 2902eac9c2dSChristoph Hellwig select PCI_DOMAINS if PCI 291625210cfSSinan Kaya select PCI_LOCKLESS_CONFIG if PCI 2926471b825SIngo Molnar select PERF_EVENTS 2933195ef59SPrarit Bhargava select RTC_LIB 294d6faca40SArnd Bergmann select RTC_MC146818_LIB 2956471b825SIngo Molnar select SPARSE_IRQ 2966471b825SIngo Molnar select SYSCTL_EXCEPTION_TRACE 29715f4eae7SAndy Lutomirski select THREAD_INFO_IN_TASK 2984aae683fSMasahiro Yamada select TRACE_IRQFLAGS_SUPPORT 2994510bffbSMark Rutland select TRACE_IRQFLAGS_NMI_SUPPORT 3006471b825SIngo Molnar select USER_STACKTRACE_SUPPORT 3013b02a051SIngo Molnar select HAVE_ARCH_KCSAN if X86_64 3020c608dadSAubrey Li select PROC_PID_ARCH_STATUS if PROC_FS 30350468e43SJarkko Sakkinen select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX 304d49a0626SPeter Zijlstra select FUNCTION_ALIGNMENT_16B if X86_64 || X86_ALIGNMENT_16 305d49a0626SPeter Zijlstra select FUNCTION_ALIGNMENT_4B 3069e2b4be3SNayna Jain imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 307ceea991aSJiri Olsa select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 3087d8330a5SBalbir Singh 309ba7e4d13SIngo Molnarconfig INSTRUCTION_DECODER 3103120e25eSJan Beulich def_bool y 3113120e25eSJan Beulich depends on KPROBES || PERF_EVENTS || UPROBES 312ba7e4d13SIngo Molnar 31351b26adaSLinus Torvaldsconfig OUTPUT_FORMAT 31451b26adaSLinus Torvalds string 31551b26adaSLinus Torvalds default "elf32-i386" if X86_32 31651b26adaSLinus Torvalds default "elf64-x86-64" if X86_64 31751b26adaSLinus Torvalds 3188d5fffb9SSam Ravnborgconfig LOCKDEP_SUPPORT 3193c2362e6SHarvey Harrison def_bool y 3208d5fffb9SSam Ravnborg 3218d5fffb9SSam Ravnborgconfig STACKTRACE_SUPPORT 3223c2362e6SHarvey Harrison def_bool y 3238d5fffb9SSam Ravnborg 3248d5fffb9SSam Ravnborgconfig MMU 3253c2362e6SHarvey Harrison def_bool y 3268d5fffb9SSam Ravnborg 3279e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MIN 3289e08f57dSDaniel Cashman default 28 if 64BIT 3299e08f57dSDaniel Cashman default 8 3309e08f57dSDaniel Cashman 3319e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MAX 3329e08f57dSDaniel Cashman default 32 if 64BIT 3339e08f57dSDaniel Cashman default 16 3349e08f57dSDaniel Cashman 3359e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MIN 3369e08f57dSDaniel Cashman default 8 3379e08f57dSDaniel Cashman 3389e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MAX 3399e08f57dSDaniel Cashman default 16 3409e08f57dSDaniel Cashman 3418d5fffb9SSam Ravnborgconfig SBUS 3428d5fffb9SSam Ravnborg bool 3438d5fffb9SSam Ravnborg 3448d5fffb9SSam Ravnborgconfig GENERIC_ISA_DMA 3453120e25eSJan Beulich def_bool y 3463120e25eSJan Beulich depends on ISA_DMA_API 3478d5fffb9SSam Ravnborg 348d911c67eSAlexander Potapenkoconfig GENERIC_CSUM 349d911c67eSAlexander Potapenko bool 350d911c67eSAlexander Potapenko default y if KMSAN || KASAN 351d911c67eSAlexander Potapenko 3528d5fffb9SSam Ravnborgconfig GENERIC_BUG 3533c2362e6SHarvey Harrison def_bool y 3548d5fffb9SSam Ravnborg depends on BUG 355b93a531eSJan Beulich select GENERIC_BUG_RELATIVE_POINTERS if X86_64 356b93a531eSJan Beulich 357b93a531eSJan Beulichconfig GENERIC_BUG_RELATIVE_POINTERS 358b93a531eSJan Beulich bool 3598d5fffb9SSam Ravnborg 3608d5fffb9SSam Ravnborgconfig ARCH_MAY_HAVE_PC_FDC 3613120e25eSJan Beulich def_bool y 3623120e25eSJan Beulich depends on ISA_DMA_API 3638d5fffb9SSam Ravnborg 3641032c0baSSam Ravnborgconfig GENERIC_CALIBRATE_DELAY 3651032c0baSSam Ravnborg def_bool y 3661032c0baSSam Ravnborg 3679a0b8415Svenkatesh.pallipadi@intel.comconfig ARCH_HAS_CPU_RELAX 3689a0b8415Svenkatesh.pallipadi@intel.com def_bool y 3698d5fffb9SSam Ravnborg 370801e4062SJohannes Bergconfig ARCH_HIBERNATION_POSSIBLE 371801e4062SJohannes Berg def_bool y 372801e4062SJohannes Berg 373f4cb5700SJohannes Bergconfig ARCH_SUSPEND_POSSIBLE 374f4cb5700SJohannes Berg def_bool y 375f4cb5700SJohannes Berg 3768d5fffb9SSam Ravnborgconfig AUDIT_ARCH 377e0fd24a3SJan Beulich def_bool y if X86_64 3788d5fffb9SSam Ravnborg 379d6f2d75aSAndrey Ryabininconfig KASAN_SHADOW_OFFSET 380d6f2d75aSAndrey Ryabinin hex 381d6f2d75aSAndrey Ryabinin depends on KASAN 382d6f2d75aSAndrey Ryabinin default 0xdffffc0000000000 383d6f2d75aSAndrey Ryabinin 38469575d38SShane Wangconfig HAVE_INTEL_TXT 38569575d38SShane Wang def_bool y 3866ea30386SKees Cook depends on INTEL_IOMMU && ACPI 38769575d38SShane Wang 3886b0c3d44SSam Ravnborgconfig X86_32_SMP 3896b0c3d44SSam Ravnborg def_bool y 3906b0c3d44SSam Ravnborg depends on X86_32 && SMP 3916b0c3d44SSam Ravnborg 3926b0c3d44SSam Ravnborgconfig X86_64_SMP 3936b0c3d44SSam Ravnborg def_bool y 3946b0c3d44SSam Ravnborg depends on X86_64 && SMP 3956b0c3d44SSam Ravnborg 3962b144498SSrikar Dronamrajuconfig ARCH_SUPPORTS_UPROBES 3972b144498SSrikar Dronamraju def_bool y 3982b144498SSrikar Dronamraju 399d20642f0SRob Herringconfig FIX_EARLYCON_MEM 400d20642f0SRob Herring def_bool y 401d20642f0SRob Herring 40294d49eb3SKirill A. Shutemovconfig DYNAMIC_PHYSICAL_MASK 40394d49eb3SKirill A. Shutemov bool 40494d49eb3SKirill A. Shutemov 40598233368SKirill A. Shutemovconfig PGTABLE_LEVELS 40698233368SKirill A. Shutemov int 40777ef56e4SKirill A. Shutemov default 5 if X86_5LEVEL 40898233368SKirill A. Shutemov default 4 if X86_64 40998233368SKirill A. Shutemov default 3 if X86_PAE 41098233368SKirill A. Shutemov default 2 41198233368SKirill A. Shutemov 4122a61f474SMasahiro Yamadaconfig CC_HAS_SANE_STACKPROTECTOR 4132a61f474SMasahiro Yamada bool 4141b866781SNathan Chancellor default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT 4151b866781SNathan Chancellor default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) 4162a61f474SMasahiro Yamada help 4172a61f474SMasahiro Yamada We have to make sure stack protector is unconditionally disabled if 4183fb0fdb3SAndy Lutomirski the compiler produces broken code or if it does not let us control 4193fb0fdb3SAndy Lutomirski the segment on 32-bit kernels. 4202a61f474SMasahiro Yamada 421506f1d07SSam Ravnborgmenu "Processor type and features" 422506f1d07SSam Ravnborg 423506f1d07SSam Ravnborgconfig SMP 424506f1d07SSam Ravnborg bool "Symmetric multi-processing support" 425a7f7f624SMasahiro Yamada help 426506f1d07SSam Ravnborg This enables support for systems with more than one CPU. If you have 4274a474157SRobert Graffham a system with only one CPU, say N. If you have a system with more 4284a474157SRobert Graffham than one CPU, say Y. 429506f1d07SSam Ravnborg 4304a474157SRobert Graffham If you say N here, the kernel will run on uni- and multiprocessor 431506f1d07SSam Ravnborg machines, but will use only one CPU of a multiprocessor machine. If 432506f1d07SSam Ravnborg you say Y here, the kernel will run on many, but not all, 4334a474157SRobert Graffham uniprocessor machines. On a uniprocessor machine, the kernel 434506f1d07SSam Ravnborg will run faster if you say N here. 435506f1d07SSam Ravnborg 436506f1d07SSam Ravnborg Note that if you say Y here and choose architecture "586" or 437506f1d07SSam Ravnborg "Pentium" under "Processor family", the kernel will not work on 486 438506f1d07SSam Ravnborg architectures. Similarly, multiprocessor kernels for the "PPro" 439506f1d07SSam Ravnborg architecture may not work on all Pentium based boards. 440506f1d07SSam Ravnborg 441506f1d07SSam Ravnborg People using multiprocessor machines who say Y here should also say 442506f1d07SSam Ravnborg Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 443506f1d07SSam Ravnborg Management" code will be disabled if you say Y here. 444506f1d07SSam Ravnborg 445ff61f079SJonathan Corbet See also <file:Documentation/arch/x86/i386/IO-APIC.rst>, 4464f4cfa6cSMauro Carvalho Chehab <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 447506f1d07SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 448506f1d07SSam Ravnborg 449506f1d07SSam Ravnborg If you don't know what to do here, say N. 450506f1d07SSam Ravnborg 45106cd9a7dSYinghai Luconfig X86_X2APIC 45206cd9a7dSYinghai Lu bool "Support x2apic" 45319e3d60dSJan Kiszka depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 454a7f7f624SMasahiro Yamada help 45506cd9a7dSYinghai Lu This enables x2apic support on CPUs that have this feature. 45606cd9a7dSYinghai Lu 45706cd9a7dSYinghai Lu This allows 32-bit apic IDs (so it can support very large systems), 45806cd9a7dSYinghai Lu and accesses the local apic via MSRs not via mmio. 45906cd9a7dSYinghai Lu 460b8d1d163SDaniel Sneddon Some Intel systems circa 2022 and later are locked into x2APIC mode 461b8d1d163SDaniel Sneddon and can not fall back to the legacy APIC modes if SGX or TDX are 462e3998434SMateusz Jończyk enabled in the BIOS. They will boot with very reduced functionality 463e3998434SMateusz Jończyk without enabling this option. 464b8d1d163SDaniel Sneddon 46506cd9a7dSYinghai Lu If you don't know what to do here, say N. 46606cd9a7dSYinghai Lu 4676695c85bSYinghai Luconfig X86_MPPARSE 4684590d98fSAndy Shevchenko bool "Enable MPS table" if ACPI 4697a527688SJan Beulich default y 4705ab74722SIngo Molnar depends on X86_LOCAL_APIC 471a7f7f624SMasahiro Yamada help 4726695c85bSYinghai Lu For old smp systems that do not have proper acpi support. Newer systems 4736695c85bSYinghai Lu (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 4746695c85bSYinghai Lu 475ddd70cf9SJun Nakajimaconfig GOLDFISH 476ddd70cf9SJun Nakajima def_bool y 477ddd70cf9SJun Nakajima depends on X86_GOLDFISH 478ddd70cf9SJun Nakajima 479e6d42931SJohannes Weinerconfig X86_CPU_RESCTRL 480e6d42931SJohannes Weiner bool "x86 CPU resource control support" 4816fe07ce3SBabu Moger depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 48259fe5a77SThomas Gleixner select KERNFS 483e79f15a4SChen Yu select PROC_CPU_RESCTRL if PROC_FS 48478e99b4aSFenghua Yu help 485e6d42931SJohannes Weiner Enable x86 CPU resource control support. 4866fe07ce3SBabu Moger 4876fe07ce3SBabu Moger Provide support for the allocation and monitoring of system resources 4886fe07ce3SBabu Moger usage by the CPU. 4896fe07ce3SBabu Moger 4906fe07ce3SBabu Moger Intel calls this Intel Resource Director Technology 4916fe07ce3SBabu Moger (Intel(R) RDT). More information about RDT can be found in the 4926fe07ce3SBabu Moger Intel x86 Architecture Software Developer Manual. 4936fe07ce3SBabu Moger 4946fe07ce3SBabu Moger AMD calls this AMD Platform Quality of Service (AMD QoS). 4956fe07ce3SBabu Moger More information about AMD QoS can be found in the AMD64 Technology 4966fe07ce3SBabu Moger Platform Quality of Service Extensions manual. 49778e99b4aSFenghua Yu 49878e99b4aSFenghua Yu Say N if unsure. 49978e99b4aSFenghua Yu 5008425091fSRavikiran G Thirumalaiif X86_32 501a0d0bb4dSRandy Dunlapconfig X86_BIGSMP 502a0d0bb4dSRandy Dunlap bool "Support for big SMP systems with more than 8 CPUs" 503a0d0bb4dSRandy Dunlap depends on SMP 504a7f7f624SMasahiro Yamada help 505e133f6eaSRandy Dunlap This option is needed for the systems that have more than 8 CPUs. 506a0d0bb4dSRandy Dunlap 507c5c606d9SRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 508c5c606d9SRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 509c5c606d9SRavikiran G Thirumalai default y 510a7f7f624SMasahiro Yamada help 51106ac8346SIngo Molnar If you disable this option then the kernel will only support 51206ac8346SIngo Molnar standard PC platforms. (which covers the vast majority of 51306ac8346SIngo Molnar systems out there.) 51406ac8346SIngo Molnar 5158425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5168425091fSRavikiran G Thirumalai for the following (non-PC) 32 bit x86 platforms: 517cb7b8023SBen Hutchings Goldfish (Android emulator) 5188425091fSRavikiran G Thirumalai AMD Elan 5198425091fSRavikiran G Thirumalai RDC R-321x SoC 5208425091fSRavikiran G Thirumalai SGI 320/540 (Visual Workstation) 52183125a3aSAlessandro Rubini STA2X11-based (e.g. Northville) 5223f4110a4SThomas Gleixner Moorestown MID devices 52306ac8346SIngo Molnar 52406ac8346SIngo Molnar If you have one of these systems, or if you want to build a 52506ac8346SIngo Molnar generic distribution kernel, say Y here - otherwise say N. 526758cd94aSJuerg Haefligerendif # X86_32 52706ac8346SIngo Molnar 5288425091fSRavikiran G Thirumalaiif X86_64 5298425091fSRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 5308425091fSRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 5318425091fSRavikiran G Thirumalai default y 532a7f7f624SMasahiro Yamada help 5338425091fSRavikiran G Thirumalai If you disable this option then the kernel will only support 5348425091fSRavikiran G Thirumalai standard PC platforms. (which covers the vast majority of 5358425091fSRavikiran G Thirumalai systems out there.) 5368425091fSRavikiran G Thirumalai 5378425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5388425091fSRavikiran G Thirumalai for the following (non-PC) 64 bit x86 platforms: 53944b111b5SSteffen Persvold Numascale NumaChip 5408425091fSRavikiran G Thirumalai ScaleMP vSMP 5418425091fSRavikiran G Thirumalai SGI Ultraviolet 5428425091fSRavikiran G Thirumalai 5438425091fSRavikiran G Thirumalai If you have one of these systems, or if you want to build a 5448425091fSRavikiran G Thirumalai generic distribution kernel, say Y here - otherwise say N. 545758cd94aSJuerg Haefligerendif # X86_64 546c5c606d9SRavikiran G Thirumalai# This is an alphabetically sorted list of 64 bit extended platforms 547c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 54844b111b5SSteffen Persvoldconfig X86_NUMACHIP 54944b111b5SSteffen Persvold bool "Numascale NumaChip" 55044b111b5SSteffen Persvold depends on X86_64 55144b111b5SSteffen Persvold depends on X86_EXTENDED_PLATFORM 55244b111b5SSteffen Persvold depends on NUMA 55344b111b5SSteffen Persvold depends on SMP 55444b111b5SSteffen Persvold depends on X86_X2APIC 555f9726bfdSDaniel J Blueman depends on PCI_MMCONFIG 556a7f7f624SMasahiro Yamada help 55744b111b5SSteffen Persvold Adds support for Numascale NumaChip large-SMP systems. Needed to 55844b111b5SSteffen Persvold enable more than ~168 cores. 55944b111b5SSteffen Persvold If you don't have one of these, you should say N here. 56003b48632SNick Piggin 5616a48565eSIngo Molnarconfig X86_VSMP 562c5c606d9SRavikiran G Thirumalai bool "ScaleMP vSMP" 5636276a074SBorislav Petkov select HYPERVISOR_GUEST 5646a48565eSIngo Molnar select PARAVIRT 5656a48565eSIngo Molnar depends on X86_64 && PCI 566c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 567ead91d4bSShai Fultheim depends on SMP 568a7f7f624SMasahiro Yamada help 5696a48565eSIngo Molnar Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 5706a48565eSIngo Molnar supposed to run on these EM64T-based machines. Only choose this option 5716a48565eSIngo Molnar if you have one of these machines. 5726a48565eSIngo Molnar 573c5c606d9SRavikiran G Thirumalaiconfig X86_UV 574c5c606d9SRavikiran G Thirumalai bool "SGI Ultraviolet" 575c5c606d9SRavikiran G Thirumalai depends on X86_64 576c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 57754c28d29SJack Steiner depends on NUMA 5781ecb4ae5SAndrew Morton depends on EFI 579c2209ea5SIngo Molnar depends on KEXEC_CORE 5809d6c26e7SSuresh Siddha depends on X86_X2APIC 5811222e564SIngo Molnar depends on PCI 582a7f7f624SMasahiro Yamada help 583c5c606d9SRavikiran G Thirumalai This option is needed in order to support SGI Ultraviolet systems. 584c5c606d9SRavikiran G Thirumalai If you don't have one of these, you should say N here. 585c5c606d9SRavikiran G Thirumalai 586c5c606d9SRavikiran G Thirumalai# Following is an alphabetically sorted list of 32 bit extended platforms 587c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 588506f1d07SSam Ravnborg 589ddd70cf9SJun Nakajimaconfig X86_GOLDFISH 590ddd70cf9SJun Nakajima bool "Goldfish (Virtual Platform)" 591cb7b8023SBen Hutchings depends on X86_EXTENDED_PLATFORM 592a7f7f624SMasahiro Yamada help 593ddd70cf9SJun Nakajima Enable support for the Goldfish virtual platform used primarily 594ddd70cf9SJun Nakajima for Android development. Unless you are building for the Android 595ddd70cf9SJun Nakajima Goldfish emulator say N here. 596ddd70cf9SJun Nakajima 597c751e17bSThomas Gleixnerconfig X86_INTEL_CE 598c751e17bSThomas Gleixner bool "CE4100 TV platform" 599c751e17bSThomas Gleixner depends on PCI 600c751e17bSThomas Gleixner depends on PCI_GODIRECT 6016084a6e2SJiang Liu depends on X86_IO_APIC 602c751e17bSThomas Gleixner depends on X86_32 603c751e17bSThomas Gleixner depends on X86_EXTENDED_PLATFORM 60437bc9f50SDirk Brandewie select X86_REBOOTFIXUPS 605da6b737bSSebastian Andrzej Siewior select OF 606da6b737bSSebastian Andrzej Siewior select OF_EARLY_FLATTREE 607a7f7f624SMasahiro Yamada help 608c751e17bSThomas Gleixner Select for the Intel CE media processor (CE4100) SOC. 609c751e17bSThomas Gleixner This option compiles in support for the CE4100 SOC for settop 610c751e17bSThomas Gleixner boxes and media devices. 611c751e17bSThomas Gleixner 6124cb9b00fSDavid Cohenconfig X86_INTEL_MID 61343605ef1SAlan Cox bool "Intel MID platform support" 61443605ef1SAlan Cox depends on X86_EXTENDED_PLATFORM 615edc6bc78SDavid Cohen depends on X86_PLATFORM_DEVICES 6161ea7c673SAlan Cox depends on PCI 6173fda5bb4SAndy Shevchenko depends on X86_64 || (PCI_GOANY && X86_32) 6181ea7c673SAlan Cox depends on X86_IO_APIC 6194cb9b00fSDavid Cohen select I2C 6207c9c3a1eSAlan Cox select DW_APB_TIMER 62154b34aa0SMika Westerberg select INTEL_SCU_PCI 622a7f7f624SMasahiro Yamada help 6234cb9b00fSDavid Cohen Select to build a kernel capable of supporting Intel MID (Mobile 6244cb9b00fSDavid Cohen Internet Device) platform systems which do not have the PCI legacy 6254cb9b00fSDavid Cohen interfaces. If you are building for a PC class system say N here. 6261ea7c673SAlan Cox 6274cb9b00fSDavid Cohen Intel MID platforms are based on an Intel processor and chipset which 6284cb9b00fSDavid Cohen consume less power than most of the x86 derivatives. 62943605ef1SAlan Cox 6308bbc2a13SBryan O'Donoghueconfig X86_INTEL_QUARK 6318bbc2a13SBryan O'Donoghue bool "Intel Quark platform support" 6328bbc2a13SBryan O'Donoghue depends on X86_32 6338bbc2a13SBryan O'Donoghue depends on X86_EXTENDED_PLATFORM 6348bbc2a13SBryan O'Donoghue depends on X86_PLATFORM_DEVICES 6358bbc2a13SBryan O'Donoghue depends on X86_TSC 6368bbc2a13SBryan O'Donoghue depends on PCI 6378bbc2a13SBryan O'Donoghue depends on PCI_GOANY 6388bbc2a13SBryan O'Donoghue depends on X86_IO_APIC 6398bbc2a13SBryan O'Donoghue select IOSF_MBI 6408bbc2a13SBryan O'Donoghue select INTEL_IMR 6419ab6eb51SAndy Shevchenko select COMMON_CLK 642a7f7f624SMasahiro Yamada help 6438bbc2a13SBryan O'Donoghue Select to include support for Quark X1000 SoC. 6448bbc2a13SBryan O'Donoghue Say Y here if you have a Quark based system such as the Arduino 6458bbc2a13SBryan O'Donoghue compatible Intel Galileo. 6468bbc2a13SBryan O'Donoghue 6473d48aab1SMika Westerbergconfig X86_INTEL_LPSS 6483d48aab1SMika Westerberg bool "Intel Low Power Subsystem Support" 6495962dd22SSinan Kaya depends on X86 && ACPI && PCI 6503d48aab1SMika Westerberg select COMMON_CLK 6510f531431SMathias Nyman select PINCTRL 652eebb3e8dSAndy Shevchenko select IOSF_MBI 653a7f7f624SMasahiro Yamada help 6543d48aab1SMika Westerberg Select to build support for Intel Low Power Subsystem such as 6553d48aab1SMika Westerberg found on Intel Lynxpoint PCH. Selecting this option enables 6560f531431SMathias Nyman things like clock tree (common clock framework) and pincontrol 6570f531431SMathias Nyman which are needed by the LPSS peripheral drivers. 6583d48aab1SMika Westerberg 65992082a88SKen Xueconfig X86_AMD_PLATFORM_DEVICE 66092082a88SKen Xue bool "AMD ACPI2Platform devices support" 66192082a88SKen Xue depends on ACPI 66292082a88SKen Xue select COMMON_CLK 66392082a88SKen Xue select PINCTRL 664a7f7f624SMasahiro Yamada help 66592082a88SKen Xue Select to interpret AMD specific ACPI device to platform device 66692082a88SKen Xue such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 66792082a88SKen Xue I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 66892082a88SKen Xue implemented under PINCTRL subsystem. 66992082a88SKen Xue 670ced3ce76SDavid E. Boxconfig IOSF_MBI 671ced3ce76SDavid E. Box tristate "Intel SoC IOSF Sideband support for SoC platforms" 672ced3ce76SDavid E. Box depends on PCI 673a7f7f624SMasahiro Yamada help 674ced3ce76SDavid E. Box This option enables sideband register access support for Intel SoC 675ced3ce76SDavid E. Box platforms. On these platforms the IOSF sideband is used in lieu of 676ced3ce76SDavid E. Box MSR's for some register accesses, mostly but not limited to thermal 677ced3ce76SDavid E. Box and power. Drivers may query the availability of this device to 678ced3ce76SDavid E. Box determine if they need the sideband in order to work on these 679ced3ce76SDavid E. Box platforms. The sideband is available on the following SoC products. 680ced3ce76SDavid E. Box This list is not meant to be exclusive. 681ced3ce76SDavid E. Box - BayTrail 682ced3ce76SDavid E. Box - Braswell 683ced3ce76SDavid E. Box - Quark 684ced3ce76SDavid E. Box 685ced3ce76SDavid E. Box You should say Y if you are running a kernel on one of these SoC's. 686ced3ce76SDavid E. Box 687ed2226bdSDavid E. Boxconfig IOSF_MBI_DEBUG 688ed2226bdSDavid E. Box bool "Enable IOSF sideband access through debugfs" 689ed2226bdSDavid E. Box depends on IOSF_MBI && DEBUG_FS 690a7f7f624SMasahiro Yamada help 691ed2226bdSDavid E. Box Select this option to expose the IOSF sideband access registers (MCR, 692ed2226bdSDavid E. Box MDR, MCRX) through debugfs to write and read register information from 693ed2226bdSDavid E. Box different units on the SoC. This is most useful for obtaining device 694ed2226bdSDavid E. Box state information for debug and analysis. As this is a general access 695ed2226bdSDavid E. Box mechanism, users of this option would have specific knowledge of the 696ed2226bdSDavid E. Box device they want to access. 697ed2226bdSDavid E. Box 698ed2226bdSDavid E. Box If you don't require the option or are in doubt, say N. 699ed2226bdSDavid E. Box 700c5c606d9SRavikiran G Thirumalaiconfig X86_RDC321X 701c5c606d9SRavikiran G Thirumalai bool "RDC R-321x SoC" 702506f1d07SSam Ravnborg depends on X86_32 703c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 704c5c606d9SRavikiran G Thirumalai select M486 705c5c606d9SRavikiran G Thirumalai select X86_REBOOTFIXUPS 706a7f7f624SMasahiro Yamada help 707c5c606d9SRavikiran G Thirumalai This option is needed for RDC R-321x system-on-chip, also known 708c5c606d9SRavikiran G Thirumalai as R-8610-(G). 709c5c606d9SRavikiran G Thirumalai If you don't have one of these chips, you should say N here. 710c5c606d9SRavikiran G Thirumalai 711e0c7ae37SIngo Molnarconfig X86_32_NON_STANDARD 7129c398017SIngo Molnar bool "Support non-standard 32-bit SMP architectures" 7139c398017SIngo Molnar depends on X86_32 && SMP 714c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 715a7f7f624SMasahiro Yamada help 716b5660ba7SH. Peter Anvin This option compiles in the bigsmp and STA2X11 default 717b5660ba7SH. Peter Anvin subarchitectures. It is intended for a generic binary 718b5660ba7SH. Peter Anvin kernel. If you select them all, kernel will probe it one by 719b5660ba7SH. Peter Anvin one and will fallback to default. 720d49c4288SYinghai Lu 721c5c606d9SRavikiran G Thirumalai# Alphabetically sorted list of Non standard 32 bit platforms 722d49c4288SYinghai Lu 723d949f36fSLinus Torvaldsconfig X86_SUPPORTS_MEMORY_FAILURE 7246fc108a0SJan Beulich def_bool y 725d949f36fSLinus Torvalds # MCE code calls memory_failure(): 726d949f36fSLinus Torvalds depends on X86_MCE 727d949f36fSLinus Torvalds # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 728d949f36fSLinus Torvalds # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 729d949f36fSLinus Torvalds depends on X86_64 || !SPARSEMEM 730d949f36fSLinus Torvalds select ARCH_SUPPORTS_MEMORY_FAILURE 731d949f36fSLinus Torvalds 73283125a3aSAlessandro Rubiniconfig STA2X11 73383125a3aSAlessandro Rubini bool "STA2X11 Companion Chip Support" 73483125a3aSAlessandro Rubini depends on X86_32_NON_STANDARD && PCI 73583125a3aSAlessandro Rubini select SWIOTLB 73683125a3aSAlessandro Rubini select MFD_STA2X11 7370145071bSLinus Walleij select GPIOLIB 738a7f7f624SMasahiro Yamada help 73983125a3aSAlessandro Rubini This adds support for boards based on the STA2X11 IO-Hub, 74083125a3aSAlessandro Rubini a.k.a. "ConneXt". The chip is used in place of the standard 74183125a3aSAlessandro Rubini PC chipset, so all "standard" peripherals are missing. If this 74283125a3aSAlessandro Rubini option is selected the kernel will still be able to boot on 74383125a3aSAlessandro Rubini standard PC machines. 74483125a3aSAlessandro Rubini 74582148d1dSShérabconfig X86_32_IRIS 74682148d1dSShérab tristate "Eurobraille/Iris poweroff module" 74782148d1dSShérab depends on X86_32 748a7f7f624SMasahiro Yamada help 74982148d1dSShérab The Iris machines from EuroBraille do not have APM or ACPI support 75082148d1dSShérab to shut themselves down properly. A special I/O sequence is 75182148d1dSShérab needed to do so, which is what this module does at 75282148d1dSShérab kernel shutdown. 75382148d1dSShérab 75482148d1dSShérab This is only for Iris machines from EuroBraille. 75582148d1dSShérab 75682148d1dSShérab If unused, say N. 75782148d1dSShérab 758ae1e9130SIngo Molnarconfig SCHED_OMIT_FRAME_POINTER 7593c2362e6SHarvey Harrison def_bool y 7603c2362e6SHarvey Harrison prompt "Single-depth WCHAN output" 761a87d0914SKen Chen depends on X86 762a7f7f624SMasahiro Yamada help 763506f1d07SSam Ravnborg Calculate simpler /proc/<PID>/wchan values. If this option 764506f1d07SSam Ravnborg is disabled then wchan values will recurse back to the 765506f1d07SSam Ravnborg caller function. This provides more accurate wchan values, 766506f1d07SSam Ravnborg at the expense of slightly more scheduling overhead. 767506f1d07SSam Ravnborg 768506f1d07SSam Ravnborg If in doubt, say "Y". 769506f1d07SSam Ravnborg 7706276a074SBorislav Petkovmenuconfig HYPERVISOR_GUEST 7716276a074SBorislav Petkov bool "Linux guest support" 772a7f7f624SMasahiro Yamada help 7736276a074SBorislav Petkov Say Y here to enable options for running Linux under various hyper- 7746276a074SBorislav Petkov visors. This option enables basic hypervisor detection and platform 7756276a074SBorislav Petkov setup. 776506f1d07SSam Ravnborg 7776276a074SBorislav Petkov If you say N, all options in this submenu will be skipped and 7786276a074SBorislav Petkov disabled, and Linux guest support won't be built in. 779506f1d07SSam Ravnborg 7806276a074SBorislav Petkovif HYPERVISOR_GUEST 781506f1d07SSam Ravnborg 782e61bd94aSEduardo Pereira Habkostconfig PARAVIRT 783e61bd94aSEduardo Pereira Habkost bool "Enable paravirtualization code" 784a0e2bf7cSJuergen Gross depends on HAVE_STATIC_CALL 785a7f7f624SMasahiro Yamada help 786e61bd94aSEduardo Pereira Habkost This changes the kernel so it can modify itself when it is run 787e61bd94aSEduardo Pereira Habkost under a hypervisor, potentially improving performance significantly 788e61bd94aSEduardo Pereira Habkost over full virtualization. However, when run without a hypervisor 789e61bd94aSEduardo Pereira Habkost the kernel is theoretically slower and slightly larger. 790e61bd94aSEduardo Pereira Habkost 791c00a280aSJuergen Grossconfig PARAVIRT_XXL 792c00a280aSJuergen Gross bool 793c00a280aSJuergen Gross 7946276a074SBorislav Petkovconfig PARAVIRT_DEBUG 7956276a074SBorislav Petkov bool "paravirt-ops debugging" 7966276a074SBorislav Petkov depends on PARAVIRT && DEBUG_KERNEL 797a7f7f624SMasahiro Yamada help 7986276a074SBorislav Petkov Enable to debug paravirt_ops internals. Specifically, BUG if 7996276a074SBorislav Petkov a paravirt_op is missing when it is called. 8006276a074SBorislav Petkov 801b4ecc126SJeremy Fitzhardingeconfig PARAVIRT_SPINLOCKS 802b4ecc126SJeremy Fitzhardinge bool "Paravirtualization layer for spinlocks" 8036ea30386SKees Cook depends on PARAVIRT && SMP 804a7f7f624SMasahiro Yamada help 805b4ecc126SJeremy Fitzhardinge Paravirtualized spinlocks allow a pvops backend to replace the 806b4ecc126SJeremy Fitzhardinge spinlock implementation with something virtualization-friendly 807b4ecc126SJeremy Fitzhardinge (for example, block the virtual CPU rather than spinning). 808b4ecc126SJeremy Fitzhardinge 8094c4e4f61SRaghavendra K T It has a minimal impact on native kernels and gives a nice performance 8104c4e4f61SRaghavendra K T benefit on paravirtualized KVM / Xen kernels. 811b4ecc126SJeremy Fitzhardinge 8124c4e4f61SRaghavendra K T If you are unsure how to answer this question, answer Y. 813b4ecc126SJeremy Fitzhardinge 814ecca2502SZhao Yakuiconfig X86_HV_CALLBACK_VECTOR 815ecca2502SZhao Yakui def_bool n 816ecca2502SZhao Yakui 8176276a074SBorislav Petkovsource "arch/x86/xen/Kconfig" 8186276a074SBorislav Petkov 8196276a074SBorislav Petkovconfig KVM_GUEST 8206276a074SBorislav Petkov bool "KVM Guest support (including kvmclock)" 8216276a074SBorislav Petkov depends on PARAVIRT 8226276a074SBorislav Petkov select PARAVIRT_CLOCK 823a1c4423bSMarcelo Tosatti select ARCH_CPUIDLE_HALTPOLL 824b1d40575SVitaly Kuznetsov select X86_HV_CALLBACK_VECTOR 8256276a074SBorislav Petkov default y 826a7f7f624SMasahiro Yamada help 8276276a074SBorislav Petkov This option enables various optimizations for running under the KVM 8286276a074SBorislav Petkov hypervisor. It includes a paravirtualized clock, so that instead 8296276a074SBorislav Petkov of relying on a PIT (or probably other) emulation by the 8306276a074SBorislav Petkov underlying device model, the host provides the guest with 8316276a074SBorislav Petkov timing infrastructure such as time of day, and system time 8326276a074SBorislav Petkov 833a1c4423bSMarcelo Tosatticonfig ARCH_CPUIDLE_HALTPOLL 834a1c4423bSMarcelo Tosatti def_bool n 835a1c4423bSMarcelo Tosatti prompt "Disable host haltpoll when loading haltpoll driver" 836a1c4423bSMarcelo Tosatti help 837a1c4423bSMarcelo Tosatti If virtualized under KVM, disable host haltpoll. 838a1c4423bSMarcelo Tosatti 8397733607fSMaran Wilsonconfig PVH 8407733607fSMaran Wilson bool "Support for running PVH guests" 841a7f7f624SMasahiro Yamada help 8427733607fSMaran Wilson This option enables the PVH entry point for guest virtual machines 8437733607fSMaran Wilson as specified in the x86/HVM direct boot ABI. 8447733607fSMaran Wilson 8456276a074SBorislav Petkovconfig PARAVIRT_TIME_ACCOUNTING 8466276a074SBorislav Petkov bool "Paravirtual steal time accounting" 8476276a074SBorislav Petkov depends on PARAVIRT 848a7f7f624SMasahiro Yamada help 8496276a074SBorislav Petkov Select this option to enable fine granularity task steal time 8506276a074SBorislav Petkov accounting. Time spent executing other tasks in parallel with 8516276a074SBorislav Petkov the current vCPU is discounted from the vCPU power. To account for 8526276a074SBorislav Petkov that, there can be a small performance impact. 8536276a074SBorislav Petkov 8546276a074SBorislav Petkov If in doubt, say N here. 8556276a074SBorislav Petkov 8567af192c9SGerd Hoffmannconfig PARAVIRT_CLOCK 8577af192c9SGerd Hoffmann bool 8587af192c9SGerd Hoffmann 8594a362601SJan Kiszkaconfig JAILHOUSE_GUEST 8604a362601SJan Kiszka bool "Jailhouse non-root cell support" 861abde587bSArnd Bergmann depends on X86_64 && PCI 86287e65d05SJan Kiszka select X86_PM_TIMER 863a7f7f624SMasahiro Yamada help 8644a362601SJan Kiszka This option allows to run Linux as guest in a Jailhouse non-root 8654a362601SJan Kiszka cell. You can leave this option disabled if you only want to start 8664a362601SJan Kiszka Jailhouse and run Linux afterwards in the root cell. 8674a362601SJan Kiszka 868ec7972c9SZhao Yakuiconfig ACRN_GUEST 869ec7972c9SZhao Yakui bool "ACRN Guest support" 870ec7972c9SZhao Yakui depends on X86_64 871498ad393SZhao Yakui select X86_HV_CALLBACK_VECTOR 872ec7972c9SZhao Yakui help 873ec7972c9SZhao Yakui This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 874ec7972c9SZhao Yakui a flexible, lightweight reference open-source hypervisor, built with 875ec7972c9SZhao Yakui real-time and safety-criticality in mind. It is built for embedded 876ec7972c9SZhao Yakui IOT with small footprint and real-time features. More details can be 877ec7972c9SZhao Yakui found in https://projectacrn.org/. 878ec7972c9SZhao Yakui 87959bd54a8SKuppuswamy Sathyanarayananconfig INTEL_TDX_GUEST 88059bd54a8SKuppuswamy Sathyanarayanan bool "Intel TDX (Trust Domain Extensions) - Guest Support" 88159bd54a8SKuppuswamy Sathyanarayanan depends on X86_64 && CPU_SUP_INTEL 88259bd54a8SKuppuswamy Sathyanarayanan depends on X86_X2APIC 88375d090fdSKirill A. Shutemov depends on EFI_STUB 88441394e33SKirill A. Shutemov select ARCH_HAS_CC_PLATFORM 885968b4931SKirill A. Shutemov select X86_MEM_ENCRYPT 88677a512e3SSean Christopherson select X86_MCE 88775d090fdSKirill A. Shutemov select UNACCEPTED_MEMORY 88859bd54a8SKuppuswamy Sathyanarayanan help 88959bd54a8SKuppuswamy Sathyanarayanan Support running as a guest under Intel TDX. Without this support, 89059bd54a8SKuppuswamy Sathyanarayanan the guest kernel can not boot or run under TDX. 89159bd54a8SKuppuswamy Sathyanarayanan TDX includes memory encryption and integrity capabilities 89259bd54a8SKuppuswamy Sathyanarayanan which protect the confidentiality and integrity of guest 89359bd54a8SKuppuswamy Sathyanarayanan memory contents and CPU state. TDX guests are protected from 89459bd54a8SKuppuswamy Sathyanarayanan some attacks from the VMM. 89559bd54a8SKuppuswamy Sathyanarayanan 8966276a074SBorislav Petkovendif # HYPERVISOR_GUEST 89797349135SJeremy Fitzhardinge 898506f1d07SSam Ravnborgsource "arch/x86/Kconfig.cpu" 899506f1d07SSam Ravnborg 900506f1d07SSam Ravnborgconfig HPET_TIMER 9013c2362e6SHarvey Harrison def_bool X86_64 902506f1d07SSam Ravnborg prompt "HPET Timer Support" if X86_32 903a7f7f624SMasahiro Yamada help 904506f1d07SSam Ravnborg Use the IA-PC HPET (High Precision Event Timer) to manage 905506f1d07SSam Ravnborg time in preference to the PIT and RTC, if a HPET is 906506f1d07SSam Ravnborg present. 907506f1d07SSam Ravnborg HPET is the next generation timer replacing legacy 8254s. 908506f1d07SSam Ravnborg The HPET provides a stable time base on SMP 909506f1d07SSam Ravnborg systems, unlike the TSC, but it is more expensive to access, 9104e7f9df2SMichael S. Tsirkin as it is off-chip. The interface used is documented 9114e7f9df2SMichael S. Tsirkin in the HPET spec, revision 1. 912506f1d07SSam Ravnborg 913506f1d07SSam Ravnborg You can safely choose Y here. However, HPET will only be 914506f1d07SSam Ravnborg activated if the platform and the BIOS support this feature. 915506f1d07SSam Ravnborg Otherwise the 8254 will be used for timing services. 916506f1d07SSam Ravnborg 917506f1d07SSam Ravnborg Choose N to continue using the legacy 8254 timer. 918506f1d07SSam Ravnborg 919506f1d07SSam Ravnborgconfig HPET_EMULATE_RTC 9203c2362e6SHarvey Harrison def_bool y 9213228e1dcSAnand K Mistry depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 922506f1d07SSam Ravnborg 9236a108a14SDavid Rientjes# Mark as expert because too many people got it wrong. 924506f1d07SSam Ravnborg# The code disables itself when not needed. 9257ae9392cSThomas Petazzoniconfig DMI 9267ae9392cSThomas Petazzoni default y 927cf074402SArd Biesheuvel select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 9286a108a14SDavid Rientjes bool "Enable DMI scanning" if EXPERT 929a7f7f624SMasahiro Yamada help 9307ae9392cSThomas Petazzoni Enabled scanning of DMI to identify machine quirks. Say Y 9317ae9392cSThomas Petazzoni here unless you have verified that your setup is not 9327ae9392cSThomas Petazzoni affected by entries in the DMI blacklist. Required by PNP 9337ae9392cSThomas Petazzoni BIOS code. 9347ae9392cSThomas Petazzoni 935506f1d07SSam Ravnborgconfig GART_IOMMU 93638901f1cSAndi Kleen bool "Old AMD GART IOMMU support" 9372f9237d4SChristoph Hellwig select DMA_OPS 938a4ce5a48SChristoph Hellwig select IOMMU_HELPER 939506f1d07SSam Ravnborg select SWIOTLB 94023ac4ae8SAndreas Herrmann depends on X86_64 && PCI && AMD_NB 941a7f7f624SMasahiro Yamada help 942ced3c42cSIngo Molnar Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 943ced3c42cSIngo Molnar GART based hardware IOMMUs. 944ced3c42cSIngo Molnar 945ced3c42cSIngo Molnar The GART supports full DMA access for devices with 32-bit access 946ced3c42cSIngo Molnar limitations, on systems with more than 3 GB. This is usually needed 947ced3c42cSIngo Molnar for USB, sound, many IDE/SATA chipsets and some other devices. 948ced3c42cSIngo Molnar 949ced3c42cSIngo Molnar Newer systems typically have a modern AMD IOMMU, supported via 950ced3c42cSIngo Molnar the CONFIG_AMD_IOMMU=y config option. 951ced3c42cSIngo Molnar 952ced3c42cSIngo Molnar In normal configurations this driver is only active when needed: 953ced3c42cSIngo Molnar there's more than 3 GB of memory and the system contains a 954ced3c42cSIngo Molnar 32-bit limited device. 955ced3c42cSIngo Molnar 956ced3c42cSIngo Molnar If unsure, say Y. 957506f1d07SSam Ravnborg 9588b766b0fSMichal Suchanekconfig BOOT_VESA_SUPPORT 9598b766b0fSMichal Suchanek bool 9608b766b0fSMichal Suchanek help 9618b766b0fSMichal Suchanek If true, at least one selected framebuffer driver can take advantage 9628b766b0fSMichal Suchanek of VESA video modes set at an early boot stage via the vga= parameter. 9638b766b0fSMichal Suchanek 9641184dc2fSMike Travisconfig MAXSMP 965ddb0c5a6SSamuel Thibault bool "Enable Maximum number of SMP Processors and NUMA Nodes" 9666ea30386SKees Cook depends on X86_64 && SMP && DEBUG_KERNEL 96736f5101aSMike Travis select CPUMASK_OFFSTACK 968a7f7f624SMasahiro Yamada help 969ddb0c5a6SSamuel Thibault Enable maximum number of CPUS and NUMA Nodes for this architecture. 9701184dc2fSMike Travis If unsure, say N. 971506f1d07SSam Ravnborg 972aec6487eSIngo Molnar# 973aec6487eSIngo Molnar# The maximum number of CPUs supported: 974aec6487eSIngo Molnar# 975aec6487eSIngo Molnar# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 976aec6487eSIngo Molnar# and which can be configured interactively in the 977aec6487eSIngo Molnar# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 978aec6487eSIngo Molnar# 979aec6487eSIngo Molnar# The ranges are different on 32-bit and 64-bit kernels, depending on 980aec6487eSIngo Molnar# hardware capabilities and scalability features of the kernel. 981aec6487eSIngo Molnar# 982aec6487eSIngo Molnar# ( If MAXSMP is enabled we just use the highest possible value and disable 983aec6487eSIngo Molnar# interactive configuration. ) 984aec6487eSIngo Molnar# 985a0d0bb4dSRandy Dunlap 986aec6487eSIngo Molnarconfig NR_CPUS_RANGE_BEGIN 987a0d0bb4dSRandy Dunlap int 988aec6487eSIngo Molnar default NR_CPUS_RANGE_END if MAXSMP 989a0d0bb4dSRandy Dunlap default 1 if !SMP 990a0d0bb4dSRandy Dunlap default 2 991a0d0bb4dSRandy Dunlap 992aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 993a0d0bb4dSRandy Dunlap int 994a0d0bb4dSRandy Dunlap depends on X86_32 995aec6487eSIngo Molnar default 64 if SMP && X86_BIGSMP 996aec6487eSIngo Molnar default 8 if SMP && !X86_BIGSMP 997a0d0bb4dSRandy Dunlap default 1 if !SMP 998a0d0bb4dSRandy Dunlap 999aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 1000a0d0bb4dSRandy Dunlap int 1001a0d0bb4dSRandy Dunlap depends on X86_64 10021edae1aeSScott Wood default 8192 if SMP && CPUMASK_OFFSTACK 10031edae1aeSScott Wood default 512 if SMP && !CPUMASK_OFFSTACK 1004a0d0bb4dSRandy Dunlap default 1 if !SMP 1005aec6487eSIngo Molnar 1006aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 1007aec6487eSIngo Molnar int 1008aec6487eSIngo Molnar depends on X86_32 1009aec6487eSIngo Molnar default 32 if X86_BIGSMP 1010aec6487eSIngo Molnar default 8 if SMP 1011aec6487eSIngo Molnar default 1 if !SMP 1012aec6487eSIngo Molnar 1013aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 1014aec6487eSIngo Molnar int 1015aec6487eSIngo Molnar depends on X86_64 1016a0d0bb4dSRandy Dunlap default 8192 if MAXSMP 1017a0d0bb4dSRandy Dunlap default 64 if SMP 1018aec6487eSIngo Molnar default 1 if !SMP 1019a0d0bb4dSRandy Dunlap 1020506f1d07SSam Ravnborgconfig NR_CPUS 102136f5101aSMike Travis int "Maximum number of CPUs" if SMP && !MAXSMP 1022aec6487eSIngo Molnar range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1023aec6487eSIngo Molnar default NR_CPUS_DEFAULT 1024a7f7f624SMasahiro Yamada help 1025506f1d07SSam Ravnborg This allows you to specify the maximum number of CPUs which this 1026bb61ccc7SJosh Boyer kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1027cad14bb9SKirill A. Shutemov supported value is 8192, otherwise the maximum value is 512. The 1028506f1d07SSam Ravnborg minimum value which makes sense is 2. 1029506f1d07SSam Ravnborg 1030aec6487eSIngo Molnar This is purely to save memory: each supported CPU adds about 8KB 1031aec6487eSIngo Molnar to the kernel image. 1032506f1d07SSam Ravnborg 103366558b73STim Chenconfig SCHED_CLUSTER 103466558b73STim Chen bool "Cluster scheduler support" 103566558b73STim Chen depends on SMP 103666558b73STim Chen default y 103766558b73STim Chen help 103866558b73STim Chen Cluster scheduler support improves the CPU scheduler's decision 103966558b73STim Chen making when dealing with machines that have clusters of CPUs. 104066558b73STim Chen Cluster usually means a couple of CPUs which are placed closely 104166558b73STim Chen by sharing mid-level caches, last-level cache tags or internal 104266558b73STim Chen busses. 104366558b73STim Chen 1044506f1d07SSam Ravnborgconfig SCHED_SMT 1045dbe73364SThomas Gleixner def_bool y if SMP 1046506f1d07SSam Ravnborg 1047506f1d07SSam Ravnborgconfig SCHED_MC 10483c2362e6SHarvey Harrison def_bool y 10493c2362e6SHarvey Harrison prompt "Multi-core scheduler support" 1050c8e56d20SBorislav Petkov depends on SMP 1051a7f7f624SMasahiro Yamada help 1052506f1d07SSam Ravnborg Multi-core scheduler support improves the CPU scheduler's decision 1053506f1d07SSam Ravnborg making when dealing with multi-core CPU chips at a cost of slightly 1054506f1d07SSam Ravnborg increased overhead in some places. If unsure say N here. 1055506f1d07SSam Ravnborg 1056de966cf4STim Chenconfig SCHED_MC_PRIO 1057de966cf4STim Chen bool "CPU core priorities scheduler support" 10580a21fc12SIngo Molnar depends on SCHED_MC && CPU_SUP_INTEL 10590a21fc12SIngo Molnar select X86_INTEL_PSTATE 10600a21fc12SIngo Molnar select CPU_FREQ 1061de966cf4STim Chen default y 1062a7f7f624SMasahiro Yamada help 1063de966cf4STim Chen Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1064de966cf4STim Chen core ordering determined at manufacturing time, which allows 1065de966cf4STim Chen certain cores to reach higher turbo frequencies (when running 1066de966cf4STim Chen single threaded workloads) than others. 1067de966cf4STim Chen 1068de966cf4STim Chen Enabling this kernel feature teaches the scheduler about 1069de966cf4STim Chen the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1070de966cf4STim Chen scheduler's CPU selection logic accordingly, so that higher 1071de966cf4STim Chen overall system performance can be achieved. 1072de966cf4STim Chen 1073de966cf4STim Chen This feature will have no effect on CPUs without this feature. 1074de966cf4STim Chen 1075de966cf4STim Chen If unsure say Y here. 10765e76b2abSTim Chen 107730b8b006SThomas Gleixnerconfig UP_LATE_INIT 107830b8b006SThomas Gleixner def_bool y 1079ba360f88SThomas Gleixner depends on !SMP && X86_LOCAL_APIC 108030b8b006SThomas Gleixner 1081506f1d07SSam Ravnborgconfig X86_UP_APIC 108250849eefSJan Beulich bool "Local APIC support on uniprocessors" if !PCI_MSI 108350849eefSJan Beulich default PCI_MSI 108438a1dfdaSBryan O'Donoghue depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1085a7f7f624SMasahiro Yamada help 1086506f1d07SSam Ravnborg A local APIC (Advanced Programmable Interrupt Controller) is an 1087506f1d07SSam Ravnborg integrated interrupt controller in the CPU. If you have a single-CPU 1088506f1d07SSam Ravnborg system which has a processor with a local APIC, you can say Y here to 1089506f1d07SSam Ravnborg enable and use it. If you say Y here even though your machine doesn't 1090506f1d07SSam Ravnborg have a local APIC, then the kernel will still run with no slowdown at 1091506f1d07SSam Ravnborg all. The local APIC supports CPU-generated self-interrupts (timer, 1092506f1d07SSam Ravnborg performance counters), and the NMI watchdog which detects hard 1093506f1d07SSam Ravnborg lockups. 1094506f1d07SSam Ravnborg 1095506f1d07SSam Ravnborgconfig X86_UP_IOAPIC 1096506f1d07SSam Ravnborg bool "IO-APIC support on uniprocessors" 1097506f1d07SSam Ravnborg depends on X86_UP_APIC 1098a7f7f624SMasahiro Yamada help 1099506f1d07SSam Ravnborg An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1100506f1d07SSam Ravnborg SMP-capable replacement for PC-style interrupt controllers. Most 1101506f1d07SSam Ravnborg SMP systems and many recent uniprocessor systems have one. 1102506f1d07SSam Ravnborg 1103506f1d07SSam Ravnborg If you have a single-CPU system with an IO-APIC, you can say Y here 1104506f1d07SSam Ravnborg to use it. If you say Y here even though your machine doesn't have 1105506f1d07SSam Ravnborg an IO-APIC, then the kernel will still run with no slowdown at all. 1106506f1d07SSam Ravnborg 1107506f1d07SSam Ravnborgconfig X86_LOCAL_APIC 11083c2362e6SHarvey Harrison def_bool y 11090dbc6078SThomas Petazzoni depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1110b5dc8e6cSJiang Liu select IRQ_DOMAIN_HIERARCHY 1111506f1d07SSam Ravnborg 1112506f1d07SSam Ravnborgconfig X86_IO_APIC 1113b1da1e71SJan Beulich def_bool y 1114b1da1e71SJan Beulich depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1115506f1d07SSam Ravnborg 111641b9eb26SStefan Assmannconfig X86_REROUTE_FOR_BROKEN_BOOT_IRQS 111741b9eb26SStefan Assmann bool "Reroute for broken boot IRQs" 111841b9eb26SStefan Assmann depends on X86_IO_APIC 1119a7f7f624SMasahiro Yamada help 112041b9eb26SStefan Assmann This option enables a workaround that fixes a source of 112141b9eb26SStefan Assmann spurious interrupts. This is recommended when threaded 112241b9eb26SStefan Assmann interrupt handling is used on systems where the generation of 112341b9eb26SStefan Assmann superfluous "boot interrupts" cannot be disabled. 112441b9eb26SStefan Assmann 112541b9eb26SStefan Assmann Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 112641b9eb26SStefan Assmann entry in the chipset's IO-APIC is masked (as, e.g. the RT 112741b9eb26SStefan Assmann kernel does during interrupt handling). On chipsets where this 112841b9eb26SStefan Assmann boot IRQ generation cannot be disabled, this workaround keeps 112941b9eb26SStefan Assmann the original IRQ line masked so that only the equivalent "boot 113041b9eb26SStefan Assmann IRQ" is delivered to the CPUs. The workaround also tells the 113141b9eb26SStefan Assmann kernel to set up the IRQ handler on the boot IRQ line. In this 113241b9eb26SStefan Assmann way only one interrupt is delivered to the kernel. Otherwise 113341b9eb26SStefan Assmann the spurious second interrupt may cause the kernel to bring 113441b9eb26SStefan Assmann down (vital) interrupt lines. 113541b9eb26SStefan Assmann 113641b9eb26SStefan Assmann Only affects "broken" chipsets. Interrupt sharing may be 113741b9eb26SStefan Assmann increased on these systems. 113841b9eb26SStefan Assmann 1139506f1d07SSam Ravnborgconfig X86_MCE 1140bab9bc65SAndi Kleen bool "Machine Check / overheating reporting" 1141648ed940SChen, Gong select GENERIC_ALLOCATOR 1142e57dbaf7SBorislav Petkov default y 1143a7f7f624SMasahiro Yamada help 1144bab9bc65SAndi Kleen Machine Check support allows the processor to notify the 1145bab9bc65SAndi Kleen kernel if it detects a problem (e.g. overheating, data corruption). 1146506f1d07SSam Ravnborg The action the kernel takes depends on the severity of the problem, 1147bab9bc65SAndi Kleen ranging from warning messages to halting the machine. 11484efc0670SAndi Kleen 11495de97c9fSTony Luckconfig X86_MCELOG_LEGACY 11505de97c9fSTony Luck bool "Support for deprecated /dev/mcelog character device" 11515de97c9fSTony Luck depends on X86_MCE 1152a7f7f624SMasahiro Yamada help 11535de97c9fSTony Luck Enable support for /dev/mcelog which is needed by the old mcelog 11545de97c9fSTony Luck userspace logging daemon. Consider switching to the new generation 11555de97c9fSTony Luck rasdaemon solution. 11565de97c9fSTony Luck 1157506f1d07SSam Ravnborgconfig X86_MCE_INTEL 11583c2362e6SHarvey Harrison def_bool y 11593c2362e6SHarvey Harrison prompt "Intel MCE features" 1160c1ebf835SAndi Kleen depends on X86_MCE && X86_LOCAL_APIC 1161a7f7f624SMasahiro Yamada help 1162506f1d07SSam Ravnborg Additional support for intel specific MCE features such as 1163506f1d07SSam Ravnborg the thermal monitor. 1164506f1d07SSam Ravnborg 1165506f1d07SSam Ravnborgconfig X86_MCE_AMD 11663c2362e6SHarvey Harrison def_bool y 11673c2362e6SHarvey Harrison prompt "AMD MCE features" 1168f5382de9SYazen Ghannam depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1169a7f7f624SMasahiro Yamada help 1170506f1d07SSam Ravnborg Additional support for AMD specific MCE features such as 1171506f1d07SSam Ravnborg the DRAM Error Threshold. 1172506f1d07SSam Ravnborg 11734efc0670SAndi Kleenconfig X86_ANCIENT_MCE 11746fc108a0SJan Beulich bool "Support for old Pentium 5 / WinChip machine checks" 1175c31d9633SAndi Kleen depends on X86_32 && X86_MCE 1176a7f7f624SMasahiro Yamada help 11774efc0670SAndi Kleen Include support for machine check handling on old Pentium 5 or WinChip 11785065a706SMasanari Iida systems. These typically need to be enabled explicitly on the command 11794efc0670SAndi Kleen line. 11804efc0670SAndi Kleen 1181b2762686SAndi Kleenconfig X86_MCE_THRESHOLD 1182b2762686SAndi Kleen depends on X86_MCE_AMD || X86_MCE_INTEL 11836fc108a0SJan Beulich def_bool y 1184b2762686SAndi Kleen 1185ea149b36SAndi Kleenconfig X86_MCE_INJECT 1186bc8e80d5SBorislav Petkov depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1187ea149b36SAndi Kleen tristate "Machine check injector support" 1188a7f7f624SMasahiro Yamada help 1189ea149b36SAndi Kleen Provide support for injecting machine checks for testing purposes. 1190ea149b36SAndi Kleen If you don't know what a machine check is and you don't do kernel 1191ea149b36SAndi Kleen QA it is safe to say n. 1192ea149b36SAndi Kleen 119307dc900eSPeter Zijlstrasource "arch/x86/events/Kconfig" 1194e633c65aSKan Liang 11955aef51c3SAndy Lutomirskiconfig X86_LEGACY_VM86 11961e642812SIngo Molnar bool "Legacy VM86 support" 1197506f1d07SSam Ravnborg depends on X86_32 1198a7f7f624SMasahiro Yamada help 11995aef51c3SAndy Lutomirski This option allows user programs to put the CPU into V8086 12005aef51c3SAndy Lutomirski mode, which is an 80286-era approximation of 16-bit real mode. 12015aef51c3SAndy Lutomirski 12025aef51c3SAndy Lutomirski Some very old versions of X and/or vbetool require this option 12035aef51c3SAndy Lutomirski for user mode setting. Similarly, DOSEMU will use it if 12045aef51c3SAndy Lutomirski available to accelerate real mode DOS programs. However, any 12055aef51c3SAndy Lutomirski recent version of DOSEMU, X, or vbetool should be fully 12065aef51c3SAndy Lutomirski functional even without kernel VM86 support, as they will all 12071e642812SIngo Molnar fall back to software emulation. Nevertheless, if you are using 12081e642812SIngo Molnar a 16-bit DOS program where 16-bit performance matters, vm86 12091e642812SIngo Molnar mode might be faster than emulation and you might want to 12101e642812SIngo Molnar enable this option. 12115aef51c3SAndy Lutomirski 12121e642812SIngo Molnar Note that any app that works on a 64-bit kernel is unlikely to 12131e642812SIngo Molnar need this option, as 64-bit kernels don't, and can't, support 12141e642812SIngo Molnar V8086 mode. This option is also unrelated to 16-bit protected 12151e642812SIngo Molnar mode and is not needed to run most 16-bit programs under Wine. 12165aef51c3SAndy Lutomirski 12171e642812SIngo Molnar Enabling this option increases the complexity of the kernel 12181e642812SIngo Molnar and slows down exception handling a tiny bit. 12195aef51c3SAndy Lutomirski 12201e642812SIngo Molnar If unsure, say N here. 12215aef51c3SAndy Lutomirski 12225aef51c3SAndy Lutomirskiconfig VM86 12235aef51c3SAndy Lutomirski bool 12245aef51c3SAndy Lutomirski default X86_LEGACY_VM86 122534273f41SH. Peter Anvin 122634273f41SH. Peter Anvinconfig X86_16BIT 122734273f41SH. Peter Anvin bool "Enable support for 16-bit segments" if EXPERT 122834273f41SH. Peter Anvin default y 1229a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 1230a7f7f624SMasahiro Yamada help 123134273f41SH. Peter Anvin This option is required by programs like Wine to run 16-bit 123234273f41SH. Peter Anvin protected mode legacy code on x86 processors. Disabling 123334273f41SH. Peter Anvin this option saves about 300 bytes on i386, or around 6K text 123434273f41SH. Peter Anvin plus 16K runtime memory on x86-64, 123534273f41SH. Peter Anvin 123634273f41SH. Peter Anvinconfig X86_ESPFIX32 123734273f41SH. Peter Anvin def_bool y 123834273f41SH. Peter Anvin depends on X86_16BIT && X86_32 1239506f1d07SSam Ravnborg 1240197725deSH. Peter Anvinconfig X86_ESPFIX64 1241197725deSH. Peter Anvin def_bool y 124234273f41SH. Peter Anvin depends on X86_16BIT && X86_64 1243506f1d07SSam Ravnborg 12441ad83c85SAndy Lutomirskiconfig X86_VSYSCALL_EMULATION 12451ad83c85SAndy Lutomirski bool "Enable vsyscall emulation" if EXPERT 12461ad83c85SAndy Lutomirski default y 12471ad83c85SAndy Lutomirski depends on X86_64 1248a7f7f624SMasahiro Yamada help 12491ad83c85SAndy Lutomirski This enables emulation of the legacy vsyscall page. Disabling 12501ad83c85SAndy Lutomirski it is roughly equivalent to booting with vsyscall=none, except 12511ad83c85SAndy Lutomirski that it will also disable the helpful warning if a program 12521ad83c85SAndy Lutomirski tries to use a vsyscall. With this option set to N, offending 12531ad83c85SAndy Lutomirski programs will just segfault, citing addresses of the form 12541ad83c85SAndy Lutomirski 0xffffffffff600?00. 12551ad83c85SAndy Lutomirski 12561ad83c85SAndy Lutomirski This option is required by many programs built before 2013, and 12571ad83c85SAndy Lutomirski care should be used even with newer programs if set to N. 12581ad83c85SAndy Lutomirski 12591ad83c85SAndy Lutomirski Disabling this option saves about 7K of kernel size and 12601ad83c85SAndy Lutomirski possibly 4K of additional runtime pagetable memory. 12611ad83c85SAndy Lutomirski 1262111e7b15SThomas Gleixnerconfig X86_IOPL_IOPERM 1263111e7b15SThomas Gleixner bool "IOPERM and IOPL Emulation" 1264a24ca997SThomas Gleixner default y 1265a7f7f624SMasahiro Yamada help 1266111e7b15SThomas Gleixner This enables the ioperm() and iopl() syscalls which are necessary 1267111e7b15SThomas Gleixner for legacy applications. 1268111e7b15SThomas Gleixner 1269c8137aceSThomas Gleixner Legacy IOPL support is an overbroad mechanism which allows user 1270c8137aceSThomas Gleixner space aside of accessing all 65536 I/O ports also to disable 1271c8137aceSThomas Gleixner interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1272c8137aceSThomas Gleixner capabilities and permission from potentially active security 1273c8137aceSThomas Gleixner modules. 1274c8137aceSThomas Gleixner 1275c8137aceSThomas Gleixner The emulation restricts the functionality of the syscall to 1276c8137aceSThomas Gleixner only allowing the full range I/O port access, but prevents the 1277a24ca997SThomas Gleixner ability to disable interrupts from user space which would be 1278a24ca997SThomas Gleixner granted if the hardware IOPL mechanism would be used. 1279c8137aceSThomas Gleixner 1280506f1d07SSam Ravnborgconfig TOSHIBA 1281506f1d07SSam Ravnborg tristate "Toshiba Laptop support" 1282506f1d07SSam Ravnborg depends on X86_32 1283a7f7f624SMasahiro Yamada help 1284506f1d07SSam Ravnborg This adds a driver to safely access the System Management Mode of 1285506f1d07SSam Ravnborg the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1286506f1d07SSam Ravnborg not work on models with a Phoenix BIOS. The System Management Mode 1287506f1d07SSam Ravnborg is used to set the BIOS and power saving options on Toshiba portables. 1288506f1d07SSam Ravnborg 1289506f1d07SSam Ravnborg For information on utilities to make use of this driver see the 1290506f1d07SSam Ravnborg Toshiba Linux utilities web site at: 1291506f1d07SSam Ravnborg <http://www.buzzard.org.uk/toshiba/>. 1292506f1d07SSam Ravnborg 1293506f1d07SSam Ravnborg Say Y if you intend to run this kernel on a Toshiba portable. 1294506f1d07SSam Ravnborg Say N otherwise. 1295506f1d07SSam Ravnborg 1296506f1d07SSam Ravnborgconfig X86_REBOOTFIXUPS 12979ba16087SJan Beulich bool "Enable X86 board specific fixups for reboot" 12989ba16087SJan Beulich depends on X86_32 1299a7f7f624SMasahiro Yamada help 1300506f1d07SSam Ravnborg This enables chipset and/or board specific fixups to be done 1301506f1d07SSam Ravnborg in order to get reboot to work correctly. This is only needed on 1302506f1d07SSam Ravnborg some combinations of hardware and BIOS. The symptom, for which 1303506f1d07SSam Ravnborg this config is intended, is when reboot ends with a stalled/hung 1304506f1d07SSam Ravnborg system. 1305506f1d07SSam Ravnborg 1306506f1d07SSam Ravnborg Currently, the only fixup is for the Geode machines using 13075e3a77e9SFlorian Fainelli CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1308506f1d07SSam Ravnborg 1309506f1d07SSam Ravnborg Say Y if you want to enable the fixup. Currently, it's safe to 1310506f1d07SSam Ravnborg enable this option even if you don't need it. 1311506f1d07SSam Ravnborg Say N otherwise. 1312506f1d07SSam Ravnborg 1313506f1d07SSam Ravnborgconfig MICROCODE 1314e6bcfdd7SThomas Gleixner def_bool y 131580030e3dSBorislav Petkov depends on CPU_SUP_AMD || CPU_SUP_INTEL 1316bef83014SBorislav Petkov (AMD) select CRYPTO_LIB_SHA256 if CPU_SUP_AMD 131780cc9f10SPeter Oruba 1318*d4c860bbSThomas Gleixnerconfig MICROCODE_INITRD32 1319*d4c860bbSThomas Gleixner def_bool y 1320*d4c860bbSThomas Gleixner depends on MICROCODE && X86_32 && BLK_DEV_INITRD 1321*d4c860bbSThomas Gleixner 1322a77a94f8SBorislav Petkovconfig MICROCODE_LATE_LOADING 1323a77a94f8SBorislav Petkov bool "Late microcode loading (DANGEROUS)" 1324c02f48e0SBorislav Petkov default n 13257412a65dSThomas Gleixner depends on MICROCODE && SMP 1326a7f7f624SMasahiro Yamada help 1327a77a94f8SBorislav Petkov Loading microcode late, when the system is up and executing instructions 1328a77a94f8SBorislav Petkov is a tricky business and should be avoided if possible. Just the sequence 1329a77a94f8SBorislav Petkov of synchronizing all cores and SMT threads is one fragile dance which does 1330a77a94f8SBorislav Petkov not guarantee that cores might not softlock after the loading. Therefore, 1331fba6e6fcSThomas Gleixner use this at your own risk. Late loading taints the kernel unless the 1332fba6e6fcSThomas Gleixner microcode header indicates that it is safe for late loading via the 1333fba6e6fcSThomas Gleixner minimal revision check. This minimal revision check can be enforced on 1334fba6e6fcSThomas Gleixner the kernel command line with "microcode.minrev=Y". 1335fba6e6fcSThomas Gleixner 1336fba6e6fcSThomas Gleixnerconfig MICROCODE_LATE_FORCE_MINREV 1337fba6e6fcSThomas Gleixner bool "Enforce late microcode loading minimal revision check" 1338fba6e6fcSThomas Gleixner default n 1339fba6e6fcSThomas Gleixner depends on MICROCODE_LATE_LOADING 1340fba6e6fcSThomas Gleixner help 1341fba6e6fcSThomas Gleixner To prevent that users load microcode late which modifies already 1342fba6e6fcSThomas Gleixner in use features, newer microcode patches have a minimum revision field 1343fba6e6fcSThomas Gleixner in the microcode header, which tells the kernel which minimum 1344fba6e6fcSThomas Gleixner revision must be active in the CPU to safely load that new microcode 1345fba6e6fcSThomas Gleixner late into the running system. If disabled the check will not 1346fba6e6fcSThomas Gleixner be enforced but the kernel will be tainted when the minimal 1347fba6e6fcSThomas Gleixner revision check fails. 1348fba6e6fcSThomas Gleixner 1349fba6e6fcSThomas Gleixner This minimal revision check can also be controlled via the 1350fba6e6fcSThomas Gleixner "microcode.minrev" parameter on the kernel command line. 1351fba6e6fcSThomas Gleixner 1352fba6e6fcSThomas Gleixner If unsure say Y. 1353506f1d07SSam Ravnborg 1354506f1d07SSam Ravnborgconfig X86_MSR 1355506f1d07SSam Ravnborg tristate "/dev/cpu/*/msr - Model-specific register support" 1356a7f7f624SMasahiro Yamada help 1357506f1d07SSam Ravnborg This device gives privileged processes access to the x86 1358506f1d07SSam Ravnborg Model-Specific Registers (MSRs). It is a character device with 1359506f1d07SSam Ravnborg major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1360506f1d07SSam Ravnborg MSR accesses are directed to a specific CPU on multi-processor 1361506f1d07SSam Ravnborg systems. 1362506f1d07SSam Ravnborg 1363506f1d07SSam Ravnborgconfig X86_CPUID 1364506f1d07SSam Ravnborg tristate "/dev/cpu/*/cpuid - CPU information support" 1365a7f7f624SMasahiro Yamada help 1366506f1d07SSam Ravnborg This device gives processes access to the x86 CPUID instruction to 1367506f1d07SSam Ravnborg be executed on a specific processor. It is a character device 1368506f1d07SSam Ravnborg with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1369506f1d07SSam Ravnborg /dev/cpu/31/cpuid. 1370506f1d07SSam Ravnborg 1371506f1d07SSam Ravnborgchoice 1372506f1d07SSam Ravnborg prompt "High Memory Support" 13736fc108a0SJan Beulich default HIGHMEM4G 1374506f1d07SSam Ravnborg depends on X86_32 1375506f1d07SSam Ravnborg 1376506f1d07SSam Ravnborgconfig NOHIGHMEM 1377506f1d07SSam Ravnborg bool "off" 1378a7f7f624SMasahiro Yamada help 1379506f1d07SSam Ravnborg Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1380506f1d07SSam Ravnborg However, the address space of 32-bit x86 processors is only 4 1381506f1d07SSam Ravnborg Gigabytes large. That means that, if you have a large amount of 1382506f1d07SSam Ravnborg physical memory, not all of it can be "permanently mapped" by the 1383506f1d07SSam Ravnborg kernel. The physical memory that's not permanently mapped is called 1384506f1d07SSam Ravnborg "high memory". 1385506f1d07SSam Ravnborg 1386506f1d07SSam Ravnborg If you are compiling a kernel which will never run on a machine with 1387506f1d07SSam Ravnborg more than 1 Gigabyte total physical RAM, answer "off" here (default 1388506f1d07SSam Ravnborg choice and suitable for most users). This will result in a "3GB/1GB" 1389506f1d07SSam Ravnborg split: 3GB are mapped so that each process sees a 3GB virtual memory 1390506f1d07SSam Ravnborg space and the remaining part of the 4GB virtual memory space is used 1391506f1d07SSam Ravnborg by the kernel to permanently map as much physical memory as 1392506f1d07SSam Ravnborg possible. 1393506f1d07SSam Ravnborg 1394506f1d07SSam Ravnborg If the machine has between 1 and 4 Gigabytes physical RAM, then 1395506f1d07SSam Ravnborg answer "4GB" here. 1396506f1d07SSam Ravnborg 1397506f1d07SSam Ravnborg If more than 4 Gigabytes is used then answer "64GB" here. This 1398506f1d07SSam Ravnborg selection turns Intel PAE (Physical Address Extension) mode on. 1399506f1d07SSam Ravnborg PAE implements 3-level paging on IA32 processors. PAE is fully 1400506f1d07SSam Ravnborg supported by Linux, PAE mode is implemented on all recent Intel 1401506f1d07SSam Ravnborg processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1402506f1d07SSam Ravnborg then the kernel will not boot on CPUs that don't support PAE! 1403506f1d07SSam Ravnborg 1404506f1d07SSam Ravnborg The actual amount of total physical memory will either be 1405506f1d07SSam Ravnborg auto detected or can be forced by using a kernel command line option 1406506f1d07SSam Ravnborg such as "mem=256M". (Try "man bootparam" or see the documentation of 1407506f1d07SSam Ravnborg your boot loader (lilo or loadlin) about how to pass options to the 1408506f1d07SSam Ravnborg kernel at boot time.) 1409506f1d07SSam Ravnborg 1410506f1d07SSam Ravnborg If unsure, say "off". 1411506f1d07SSam Ravnborg 1412506f1d07SSam Ravnborgconfig HIGHMEM4G 1413506f1d07SSam Ravnborg bool "4GB" 1414a7f7f624SMasahiro Yamada help 1415506f1d07SSam Ravnborg Select this if you have a 32-bit processor and between 1 and 4 1416506f1d07SSam Ravnborg gigabytes of physical RAM. 1417506f1d07SSam Ravnborg 1418506f1d07SSam Ravnborgconfig HIGHMEM64G 1419506f1d07SSam Ravnborg bool "64GB" 1420225bac2dSLukas Bulwahn depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6 1421506f1d07SSam Ravnborg select X86_PAE 1422a7f7f624SMasahiro Yamada help 1423506f1d07SSam Ravnborg Select this if you have a 32-bit processor and more than 4 1424506f1d07SSam Ravnborg gigabytes of physical RAM. 1425506f1d07SSam Ravnborg 1426506f1d07SSam Ravnborgendchoice 1427506f1d07SSam Ravnborg 1428506f1d07SSam Ravnborgchoice 14296a108a14SDavid Rientjes prompt "Memory split" if EXPERT 1430506f1d07SSam Ravnborg default VMSPLIT_3G 1431506f1d07SSam Ravnborg depends on X86_32 1432a7f7f624SMasahiro Yamada help 1433506f1d07SSam Ravnborg Select the desired split between kernel and user memory. 1434506f1d07SSam Ravnborg 1435506f1d07SSam Ravnborg If the address range available to the kernel is less than the 1436506f1d07SSam Ravnborg physical memory installed, the remaining memory will be available 1437506f1d07SSam Ravnborg as "high memory". Accessing high memory is a little more costly 1438506f1d07SSam Ravnborg than low memory, as it needs to be mapped into the kernel first. 1439506f1d07SSam Ravnborg Note that increasing the kernel address space limits the range 1440506f1d07SSam Ravnborg available to user programs, making the address space there 1441506f1d07SSam Ravnborg tighter. Selecting anything other than the default 3G/1G split 1442506f1d07SSam Ravnborg will also likely make your kernel incompatible with binary-only 1443506f1d07SSam Ravnborg kernel modules. 1444506f1d07SSam Ravnborg 1445506f1d07SSam Ravnborg If you are not absolutely sure what you are doing, leave this 1446506f1d07SSam Ravnborg option alone! 1447506f1d07SSam Ravnborg 1448506f1d07SSam Ravnborg config VMSPLIT_3G 1449506f1d07SSam Ravnborg bool "3G/1G user/kernel split" 1450506f1d07SSam Ravnborg config VMSPLIT_3G_OPT 1451506f1d07SSam Ravnborg depends on !X86_PAE 1452506f1d07SSam Ravnborg bool "3G/1G user/kernel split (for full 1G low memory)" 1453506f1d07SSam Ravnborg config VMSPLIT_2G 1454506f1d07SSam Ravnborg bool "2G/2G user/kernel split" 1455506f1d07SSam Ravnborg config VMSPLIT_2G_OPT 1456506f1d07SSam Ravnborg depends on !X86_PAE 1457506f1d07SSam Ravnborg bool "2G/2G user/kernel split (for full 2G low memory)" 1458506f1d07SSam Ravnborg config VMSPLIT_1G 1459506f1d07SSam Ravnborg bool "1G/3G user/kernel split" 1460506f1d07SSam Ravnborgendchoice 1461506f1d07SSam Ravnborg 1462506f1d07SSam Ravnborgconfig PAGE_OFFSET 1463506f1d07SSam Ravnborg hex 1464506f1d07SSam Ravnborg default 0xB0000000 if VMSPLIT_3G_OPT 1465506f1d07SSam Ravnborg default 0x80000000 if VMSPLIT_2G 1466506f1d07SSam Ravnborg default 0x78000000 if VMSPLIT_2G_OPT 1467506f1d07SSam Ravnborg default 0x40000000 if VMSPLIT_1G 1468506f1d07SSam Ravnborg default 0xC0000000 1469506f1d07SSam Ravnborg depends on X86_32 1470506f1d07SSam Ravnborg 1471506f1d07SSam Ravnborgconfig HIGHMEM 14723c2362e6SHarvey Harrison def_bool y 1473506f1d07SSam Ravnborg depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1474506f1d07SSam Ravnborg 1475506f1d07SSam Ravnborgconfig X86_PAE 14769ba16087SJan Beulich bool "PAE (Physical Address Extension) Support" 1477506f1d07SSam Ravnborg depends on X86_32 && !HIGHMEM4G 1478d4a451d5SChristoph Hellwig select PHYS_ADDR_T_64BIT 14799d99c712SChristian Melki select SWIOTLB 1480a7f7f624SMasahiro Yamada help 1481506f1d07SSam Ravnborg PAE is required for NX support, and furthermore enables 1482506f1d07SSam Ravnborg larger swapspace support for non-overcommit purposes. It 1483506f1d07SSam Ravnborg has the cost of more pagetable lookup overhead, and also 1484506f1d07SSam Ravnborg consumes more pagetable space per process. 1485506f1d07SSam Ravnborg 148677ef56e4SKirill A. Shutemovconfig X86_5LEVEL 148777ef56e4SKirill A. Shutemov bool "Enable 5-level page tables support" 148818ec1eafSKirill A. Shutemov default y 1489eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 1490162434e7SKirill A. Shutemov select SPARSEMEM_VMEMMAP 149177ef56e4SKirill A. Shutemov depends on X86_64 1492a7f7f624SMasahiro Yamada help 149377ef56e4SKirill A. Shutemov 5-level paging enables access to larger address space: 149477ef56e4SKirill A. Shutemov up to 128 PiB of virtual address space and 4 PiB of 149577ef56e4SKirill A. Shutemov physical address space. 149677ef56e4SKirill A. Shutemov 149777ef56e4SKirill A. Shutemov It will be supported by future Intel CPUs. 149877ef56e4SKirill A. Shutemov 14996657fca0SKirill A. Shutemov A kernel with the option enabled can be booted on machines that 15006657fca0SKirill A. Shutemov support 4- or 5-level paging. 150177ef56e4SKirill A. Shutemov 1502ff61f079SJonathan Corbet See Documentation/arch/x86/x86_64/5level-paging.rst for more 150377ef56e4SKirill A. Shutemov information. 150477ef56e4SKirill A. Shutemov 150577ef56e4SKirill A. Shutemov Say N if unsure. 150677ef56e4SKirill A. Shutemov 150710971ab2SIngo Molnarconfig X86_DIRECT_GBPAGES 1508e5008abeSLuis R. Rodriguez def_bool y 15092e1da13fSVlastimil Babka depends on X86_64 1510a7f7f624SMasahiro Yamada help 151110971ab2SIngo Molnar Certain kernel features effectively disable kernel 151210971ab2SIngo Molnar linear 1 GB mappings (even if the CPU otherwise 151310971ab2SIngo Molnar supports them), so don't confuse the user by printing 151410971ab2SIngo Molnar that we have them enabled. 15159e899816SNick Piggin 15165c280cf6SThomas Gleixnerconfig X86_CPA_STATISTICS 15175c280cf6SThomas Gleixner bool "Enable statistic for Change Page Attribute" 15185c280cf6SThomas Gleixner depends on DEBUG_FS 1519a7f7f624SMasahiro Yamada help 1520b75baaf3SIngo Molnar Expose statistics about the Change Page Attribute mechanism, which 1521a943245aSColin Ian King helps to determine the effectiveness of preserving large and huge 15225c280cf6SThomas Gleixner page mappings when mapping protections are changed. 15235c280cf6SThomas Gleixner 152420f07a04SKirill A. Shutemovconfig X86_MEM_ENCRYPT 152520f07a04SKirill A. Shutemov select ARCH_HAS_FORCE_DMA_UNENCRYPTED 152620f07a04SKirill A. Shutemov select DYNAMIC_PHYSICAL_MASK 152720f07a04SKirill A. Shutemov def_bool n 152820f07a04SKirill A. Shutemov 15297744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT 15307744ccdbSTom Lendacky bool "AMD Secure Memory Encryption (SME) support" 15317744ccdbSTom Lendacky depends on X86_64 && CPU_SUP_AMD 15326c321179STom Lendacky depends on EFI_STUB 153382fef0adSDavid Rientjes select DMA_COHERENT_POOL 1534ce9084baSArd Biesheuvel select ARCH_USE_MEMREMAP_PROT 1535597cfe48SJoerg Roedel select INSTRUCTION_DECODER 1536aa5a4611STom Lendacky select ARCH_HAS_CC_PLATFORM 153720f07a04SKirill A. Shutemov select X86_MEM_ENCRYPT 15386c321179STom Lendacky select UNACCEPTED_MEMORY 1539a7f7f624SMasahiro Yamada help 15407744ccdbSTom Lendacky Say yes to enable support for the encryption of system memory. 15417744ccdbSTom Lendacky This requires an AMD processor that supports Secure Memory 15427744ccdbSTom Lendacky Encryption (SME). 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 15507ecd19cfSKefeng Wang select USE_PERCPU_NUMA_NODE_ID 1551a7f7f624SMasahiro Yamada help 1552e133f6eaSRandy Dunlap Enable NUMA (Non-Uniform Memory Access) support. 1553fd51b2d7SKOSAKI Motohiro 1554506f1d07SSam Ravnborg The kernel will try to allocate memory used by a CPU on the 1555506f1d07SSam Ravnborg local memory controller of the CPU and add some more 1556506f1d07SSam Ravnborg NUMA awareness to the kernel. 1557506f1d07SSam Ravnborg 1558c280ea5eSIngo Molnar For 64-bit this is recommended if the system is Intel Core i7 1559fd51b2d7SKOSAKI Motohiro (or later), AMD Opteron, or EM64T NUMA. 1560fd51b2d7SKOSAKI Motohiro 1561b5660ba7SH. Peter Anvin For 32-bit this is only needed if you boot a 32-bit 15627cf6c945SDavid Rientjes kernel on a 64-bit NUMA platform. 1563fd51b2d7SKOSAKI Motohiro 1564fd51b2d7SKOSAKI Motohiro Otherwise, you should say N. 1565506f1d07SSam Ravnborg 1566eec1d4faSHans Rosenfeldconfig AMD_NUMA 15673c2362e6SHarvey Harrison def_bool y 15683c2362e6SHarvey Harrison prompt "Old style AMD Opteron NUMA detection" 15695da0ef9aSTejun Heo depends on X86_64 && NUMA && PCI 1570a7f7f624SMasahiro Yamada help 1571eec1d4faSHans Rosenfeld Enable AMD NUMA node topology detection. You should say Y here if 1572eec1d4faSHans Rosenfeld you have a multi processor AMD system. This uses an old method to 1573eec1d4faSHans Rosenfeld read the NUMA configuration directly from the builtin Northbridge 1574eec1d4faSHans Rosenfeld of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1575eec1d4faSHans Rosenfeld which also takes priority if both are compiled in. 1576506f1d07SSam Ravnborg 1577506f1d07SSam Ravnborgconfig X86_64_ACPI_NUMA 15783c2362e6SHarvey Harrison def_bool y 15793c2362e6SHarvey Harrison prompt "ACPI NUMA detection" 1580506f1d07SSam Ravnborg depends on X86_64 && NUMA && ACPI && PCI 1581506f1d07SSam Ravnborg select ACPI_NUMA 1582a7f7f624SMasahiro Yamada help 1583506f1d07SSam Ravnborg Enable ACPI SRAT based node topology detection. 1584506f1d07SSam Ravnborg 1585506f1d07SSam Ravnborgconfig NUMA_EMU 1586506f1d07SSam Ravnborg bool "NUMA emulation" 15871b7e03efSTejun Heo depends on NUMA 1588a7f7f624SMasahiro Yamada help 1589506f1d07SSam Ravnborg Enable NUMA emulation. A flat machine will be split 1590506f1d07SSam Ravnborg into virtual nodes when booted with "numa=fake=N", where N is the 1591506f1d07SSam Ravnborg number of nodes. This is only useful for debugging. 1592506f1d07SSam Ravnborg 1593506f1d07SSam Ravnborgconfig NODES_SHIFT 1594d25e26b6SLinus Torvalds int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 159551591e31SDavid Rientjes range 1 10 159651591e31SDavid Rientjes default "10" if MAXSMP 1597506f1d07SSam Ravnborg default "6" if X86_64 1598506f1d07SSam Ravnborg default "3" 1599a9ee6cf5SMike Rapoport depends on NUMA 1600a7f7f624SMasahiro Yamada help 16011184dc2fSMike Travis Specify the maximum number of NUMA Nodes available on the target 1602692105b8SMatt LaPlante system. Increases memory reserved to accommodate various tables. 1603506f1d07SSam Ravnborg 1604506f1d07SSam Ravnborgconfig ARCH_FLATMEM_ENABLE 1605506f1d07SSam Ravnborg def_bool y 16063b16651fSTejun Heo depends on X86_32 && !NUMA 1607506f1d07SSam Ravnborg 1608506f1d07SSam Ravnborgconfig ARCH_SPARSEMEM_ENABLE 1609506f1d07SSam Ravnborg def_bool y 16106ea30386SKees Cook depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1611506f1d07SSam Ravnborg select SPARSEMEM_STATIC if X86_32 1612506f1d07SSam Ravnborg select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1613506f1d07SSam Ravnborg 16143b16651fSTejun Heoconfig ARCH_SPARSEMEM_DEFAULT 16156ad57f7fSMike Rapoport def_bool X86_64 || (NUMA && X86_32) 16163b16651fSTejun Heo 1617506f1d07SSam Ravnborgconfig ARCH_SELECT_MEMORY_MODEL 1618506f1d07SSam Ravnborg def_bool y 16194eda2bc3SDavid Hildenbrand depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE 1620506f1d07SSam Ravnborg 1621506f1d07SSam Ravnborgconfig ARCH_MEMORY_PROBE 1622a0842b70SToshi Kani bool "Enable sysfs memory/probe interface" 16235c11f00bSDavid Hildenbrand depends on MEMORY_HOTPLUG 1624a0842b70SToshi Kani help 1625a0842b70SToshi Kani This option enables a sysfs memory/probe interface for testing. 1626cb1aaebeSMauro Carvalho Chehab See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1627a0842b70SToshi Kani If you are unsure how to answer this question, answer N. 1628506f1d07SSam Ravnborg 16293b16651fSTejun Heoconfig ARCH_PROC_KCORE_TEXT 16303b16651fSTejun Heo def_bool y 16313b16651fSTejun Heo depends on X86_64 && PROC_KCORE 16323b16651fSTejun Heo 1633a29815a3SAvi Kivityconfig ILLEGAL_POINTER_VALUE 1634a29815a3SAvi Kivity hex 1635a29815a3SAvi Kivity default 0 if X86_32 1636a29815a3SAvi Kivity default 0xdead000000000000 if X86_64 1637a29815a3SAvi Kivity 16387a67832cSDan Williamsconfig X86_PMEM_LEGACY_DEVICE 16397a67832cSDan Williams bool 16407a67832cSDan Williams 1641ec776ef6SChristoph Hellwigconfig X86_PMEM_LEGACY 16427a67832cSDan Williams tristate "Support non-standard NVDIMMs and ADR protected memory" 16439f53f9faSDan Williams depends on PHYS_ADDR_T_64BIT 16449f53f9faSDan Williams depends on BLK_DEV 16457a67832cSDan Williams select X86_PMEM_LEGACY_DEVICE 16467b27a862SDan Williams select NUMA_KEEP_MEMINFO if NUMA 16479f53f9faSDan Williams select LIBNVDIMM 1648ec776ef6SChristoph Hellwig help 1649ec776ef6SChristoph Hellwig Treat memory marked using the non-standard e820 type of 12 as used 1650ec776ef6SChristoph Hellwig by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1651ec776ef6SChristoph Hellwig The kernel will offer these regions to the 'pmem' driver so 1652ec776ef6SChristoph Hellwig they can be used for persistent storage. 1653ec776ef6SChristoph Hellwig 1654ec776ef6SChristoph Hellwig Say Y if unsure. 1655ec776ef6SChristoph Hellwig 1656506f1d07SSam Ravnborgconfig HIGHPTE 1657506f1d07SSam Ravnborg bool "Allocate 3rd-level pagetables from highmem" 16586fc108a0SJan Beulich depends on HIGHMEM 1659a7f7f624SMasahiro Yamada help 1660506f1d07SSam Ravnborg The VM uses one page table entry for each page of physical memory. 1661506f1d07SSam Ravnborg For systems with a lot of RAM, this can be wasteful of precious 1662506f1d07SSam Ravnborg low memory. Setting this option will put user-space page table 1663506f1d07SSam Ravnborg entries in high memory. 1664506f1d07SSam Ravnborg 16659f077871SJeremy Fitzhardingeconfig X86_CHECK_BIOS_CORRUPTION 16669f077871SJeremy Fitzhardinge bool "Check for low memory corruption" 1667a7f7f624SMasahiro Yamada help 16689f077871SJeremy Fitzhardinge Periodically check for memory corruption in low memory, which 16699f077871SJeremy Fitzhardinge is suspected to be caused by BIOS. Even when enabled in the 16709f077871SJeremy Fitzhardinge configuration, it is disabled at runtime. Enable it by 16719f077871SJeremy Fitzhardinge setting "memory_corruption_check=1" on the kernel command 16729f077871SJeremy Fitzhardinge line. By default it scans the low 64k of memory every 60 16739f077871SJeremy Fitzhardinge seconds; see the memory_corruption_check_size and 16749f077871SJeremy Fitzhardinge memory_corruption_check_period parameters in 16758c27ceffSMauro Carvalho Chehab Documentation/admin-guide/kernel-parameters.rst to adjust this. 16769f077871SJeremy Fitzhardinge 16779f077871SJeremy Fitzhardinge When enabled with the default parameters, this option has 16789f077871SJeremy Fitzhardinge almost no overhead, as it reserves a relatively small amount 16799f077871SJeremy Fitzhardinge of memory and scans it infrequently. It both detects corruption 16809f077871SJeremy Fitzhardinge and prevents it from affecting the running system. 16819f077871SJeremy Fitzhardinge 16829f077871SJeremy Fitzhardinge It is, however, intended as a diagnostic tool; if repeatable 16839f077871SJeremy Fitzhardinge BIOS-originated corruption always affects the same memory, 16849f077871SJeremy Fitzhardinge you can use memmap= to prevent the kernel from using that 16859f077871SJeremy Fitzhardinge memory. 16869f077871SJeremy Fitzhardinge 1687c885df50SJeremy Fitzhardingeconfig X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1688c885df50SJeremy Fitzhardinge bool "Set the default setting of memory_corruption_check" 1689c885df50SJeremy Fitzhardinge depends on X86_CHECK_BIOS_CORRUPTION 1690c885df50SJeremy Fitzhardinge default y 1691a7f7f624SMasahiro Yamada help 1692c885df50SJeremy Fitzhardinge Set whether the default state of memory_corruption_check is 1693c885df50SJeremy Fitzhardinge on or off. 1694c885df50SJeremy Fitzhardinge 1695506f1d07SSam Ravnborgconfig MATH_EMULATION 1696506f1d07SSam Ravnborg bool 1697a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 169887d6021bSArnd Bergmann prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1699a7f7f624SMasahiro Yamada help 1700506f1d07SSam Ravnborg Linux can emulate a math coprocessor (used for floating point 1701506f1d07SSam Ravnborg operations) if you don't have one. 486DX and Pentium processors have 1702506f1d07SSam Ravnborg a math coprocessor built in, 486SX and 386 do not, unless you added 1703506f1d07SSam Ravnborg a 487DX or 387, respectively. (The messages during boot time can 1704506f1d07SSam Ravnborg give you some hints here ["man dmesg"].) Everyone needs either a 1705506f1d07SSam Ravnborg coprocessor or this emulation. 1706506f1d07SSam Ravnborg 1707506f1d07SSam Ravnborg If you don't have a math coprocessor, you need to say Y here; if you 1708506f1d07SSam Ravnborg say Y here even though you have a coprocessor, the coprocessor will 1709506f1d07SSam Ravnborg be used nevertheless. (This behavior can be changed with the kernel 1710506f1d07SSam Ravnborg command line option "no387", which comes handy if your coprocessor 1711506f1d07SSam Ravnborg is broken. Try "man bootparam" or see the documentation of your boot 1712506f1d07SSam Ravnborg loader (lilo or loadlin) about how to pass options to the kernel at 1713506f1d07SSam Ravnborg boot time.) This means that it is a good idea to say Y here if you 1714506f1d07SSam Ravnborg intend to use this kernel on different machines. 1715506f1d07SSam Ravnborg 1716506f1d07SSam Ravnborg More information about the internals of the Linux math coprocessor 1717506f1d07SSam Ravnborg emulation can be found in <file:arch/x86/math-emu/README>. 1718506f1d07SSam Ravnborg 1719506f1d07SSam Ravnborg If you are not sure, say Y; apart from resulting in a 66 KB bigger 1720506f1d07SSam Ravnborg kernel, it won't hurt. 1721506f1d07SSam Ravnborg 1722506f1d07SSam Ravnborgconfig MTRR 17236fc108a0SJan Beulich def_bool y 17246a108a14SDavid Rientjes prompt "MTRR (Memory Type Range Register) support" if EXPERT 1725a7f7f624SMasahiro Yamada help 1726506f1d07SSam Ravnborg On Intel P6 family processors (Pentium Pro, Pentium II and later) 1727506f1d07SSam Ravnborg the Memory Type Range Registers (MTRRs) may be used to control 1728506f1d07SSam Ravnborg processor access to memory ranges. This is most useful if you have 1729506f1d07SSam Ravnborg a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1730506f1d07SSam Ravnborg allows bus write transfers to be combined into a larger transfer 1731506f1d07SSam Ravnborg before bursting over the PCI/AGP bus. This can increase performance 1732506f1d07SSam Ravnborg of image write operations 2.5 times or more. Saying Y here creates a 1733506f1d07SSam Ravnborg /proc/mtrr file which may be used to manipulate your processor's 1734506f1d07SSam Ravnborg MTRRs. Typically the X server should use this. 1735506f1d07SSam Ravnborg 1736506f1d07SSam Ravnborg This code has a reasonably generic interface so that similar 1737506f1d07SSam Ravnborg control registers on other processors can be easily supported 1738506f1d07SSam Ravnborg as well: 1739506f1d07SSam Ravnborg 1740506f1d07SSam Ravnborg The Cyrix 6x86, 6x86MX and M II processors have Address Range 1741506f1d07SSam Ravnborg Registers (ARRs) which provide a similar functionality to MTRRs. For 1742506f1d07SSam Ravnborg these, the ARRs are used to emulate the MTRRs. 1743506f1d07SSam Ravnborg The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1744506f1d07SSam Ravnborg MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1745506f1d07SSam Ravnborg write-combining. All of these processors are supported by this code 1746506f1d07SSam Ravnborg and it makes sense to say Y here if you have one of them. 1747506f1d07SSam Ravnborg 1748506f1d07SSam Ravnborg Saying Y here also fixes a problem with buggy SMP BIOSes which only 1749506f1d07SSam Ravnborg set the MTRRs for the boot CPU and not for the secondary CPUs. This 1750506f1d07SSam Ravnborg can lead to all sorts of problems, so it's good to say Y here. 1751506f1d07SSam Ravnborg 1752506f1d07SSam Ravnborg You can safely say Y even if your machine doesn't have MTRRs, you'll 1753506f1d07SSam Ravnborg just add about 9 KB to your kernel. 1754506f1d07SSam Ravnborg 1755ff61f079SJonathan Corbet See <file:Documentation/arch/x86/mtrr.rst> for more information. 1756506f1d07SSam Ravnborg 175795ffa243SYinghai Luconfig MTRR_SANITIZER 17582ffb3501SYinghai Lu def_bool y 175995ffa243SYinghai Lu prompt "MTRR cleanup support" 176095ffa243SYinghai Lu depends on MTRR 1761a7f7f624SMasahiro Yamada help 1762aba3728cSThomas Gleixner Convert MTRR layout from continuous to discrete, so X drivers can 1763aba3728cSThomas Gleixner add writeback entries. 176495ffa243SYinghai Lu 1765aba3728cSThomas Gleixner Can be disabled with disable_mtrr_cleanup on the kernel command line. 1766692105b8SMatt LaPlante The largest mtrr entry size for a continuous block can be set with 1767aba3728cSThomas Gleixner mtrr_chunk_size. 176895ffa243SYinghai Lu 17692ffb3501SYinghai Lu If unsure, say Y. 177095ffa243SYinghai Lu 177195ffa243SYinghai Luconfig MTRR_SANITIZER_ENABLE_DEFAULT 1772f5098d62SYinghai Lu int "MTRR cleanup enable value (0-1)" 1773f5098d62SYinghai Lu range 0 1 1774f5098d62SYinghai Lu default "0" 177595ffa243SYinghai Lu depends on MTRR_SANITIZER 1776a7f7f624SMasahiro Yamada help 1777f5098d62SYinghai Lu Enable mtrr cleanup default value 177895ffa243SYinghai Lu 177912031a62SYinghai Luconfig MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 178012031a62SYinghai Lu int "MTRR cleanup spare reg num (0-7)" 178112031a62SYinghai Lu range 0 7 178212031a62SYinghai Lu default "1" 178312031a62SYinghai Lu depends on MTRR_SANITIZER 1784a7f7f624SMasahiro Yamada help 178512031a62SYinghai Lu mtrr cleanup spare entries default, it can be changed via 1786aba3728cSThomas Gleixner mtrr_spare_reg_nr=N on the kernel command line. 178712031a62SYinghai Lu 17882e5d9c85Svenkatesh.pallipadi@intel.comconfig X86_PAT 17896fc108a0SJan Beulich def_bool y 17906a108a14SDavid Rientjes prompt "x86 PAT support" if EXPERT 17912a8a2719SIngo Molnar depends on MTRR 1792a7f7f624SMasahiro Yamada help 17932e5d9c85Svenkatesh.pallipadi@intel.com Use PAT attributes to setup page level cache control. 1794042b78e4SVenki Pallipadi 17952e5d9c85Svenkatesh.pallipadi@intel.com PATs are the modern equivalents of MTRRs and are much more 17962e5d9c85Svenkatesh.pallipadi@intel.com flexible than MTRRs. 17972e5d9c85Svenkatesh.pallipadi@intel.com 17982e5d9c85Svenkatesh.pallipadi@intel.com Say N here if you see bootup problems (boot crash, boot hang, 1799042b78e4SVenki Pallipadi spontaneous reboots) or a non-working video driver. 18002e5d9c85Svenkatesh.pallipadi@intel.com 18012e5d9c85Svenkatesh.pallipadi@intel.com If unsure, say Y. 18022e5d9c85Svenkatesh.pallipadi@intel.com 180346cf98cdSVenkatesh Pallipadiconfig ARCH_USES_PG_UNCACHED 180446cf98cdSVenkatesh Pallipadi def_bool y 180546cf98cdSVenkatesh Pallipadi depends on X86_PAT 180646cf98cdSVenkatesh Pallipadi 1807b971880fSBabu Mogerconfig X86_UMIP 1808796ebc81SRicardo Neri def_bool y 1809b971880fSBabu Moger prompt "User Mode Instruction Prevention" if EXPERT 1810a7f7f624SMasahiro Yamada help 1811b971880fSBabu Moger User Mode Instruction Prevention (UMIP) is a security feature in 1812b971880fSBabu Moger some x86 processors. If enabled, a general protection fault is 1813b971880fSBabu Moger issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1814b971880fSBabu Moger executed in user mode. These instructions unnecessarily expose 1815b971880fSBabu Moger information about the hardware state. 1816796ebc81SRicardo Neri 1817796ebc81SRicardo Neri The vast majority of applications do not use these instructions. 1818796ebc81SRicardo Neri For the very few that do, software emulation is provided in 1819796ebc81SRicardo Neri specific cases in protected and virtual-8086 modes. Emulated 1820796ebc81SRicardo Neri results are dummy. 1821aa35f896SRicardo Neri 1822156ff4a5SPeter Zijlstraconfig CC_HAS_IBT 1823156ff4a5SPeter Zijlstra # GCC >= 9 and binutils >= 2.29 1824156ff4a5SPeter Zijlstra # Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654 1825156ff4a5SPeter Zijlstra # Clang/LLVM >= 14 1826262448f3SNathan Chancellor # https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f 1827262448f3SNathan Chancellor # https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332 1828156ff4a5SPeter Zijlstra def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \ 1829262448f3SNathan Chancellor (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \ 1830156ff4a5SPeter Zijlstra $(as-instr,endbr64) 1831156ff4a5SPeter Zijlstra 183218e66b69SRick Edgecombeconfig X86_CET 183318e66b69SRick Edgecombe def_bool n 183418e66b69SRick Edgecombe help 183518e66b69SRick Edgecombe CET features configured (Shadow stack or IBT) 183618e66b69SRick Edgecombe 1837156ff4a5SPeter Zijlstraconfig X86_KERNEL_IBT 1838156ff4a5SPeter Zijlstra prompt "Indirect Branch Tracking" 18394fd5f70cSKees Cook def_bool y 184003f16cd0SJosh Poimboeuf depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL 1841f6a2c2b2SNathan Chancellor # https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f 1842f6a2c2b2SNathan Chancellor depends on !LD_IS_LLD || LLD_VERSION >= 140000 184303f16cd0SJosh Poimboeuf select OBJTOOL 184418e66b69SRick Edgecombe select X86_CET 1845156ff4a5SPeter Zijlstra help 1846156ff4a5SPeter Zijlstra Build the kernel with support for Indirect Branch Tracking, a 1847156ff4a5SPeter Zijlstra hardware support course-grain forward-edge Control Flow Integrity 1848156ff4a5SPeter Zijlstra protection. It enforces that all indirect calls must land on 1849156ff4a5SPeter Zijlstra an ENDBR instruction, as such, the compiler will instrument the 1850156ff4a5SPeter Zijlstra code with them to make this happen. 1851156ff4a5SPeter Zijlstra 1852ed53a0d9SPeter Zijlstra In addition to building the kernel with IBT, seal all functions that 18534cdfc11bSNur Hussein are not indirect call targets, avoiding them ever becoming one. 1854ed53a0d9SPeter Zijlstra 1855ed53a0d9SPeter Zijlstra This requires LTO like objtool runs and will slow down the build. It 1856ed53a0d9SPeter Zijlstra does significantly reduce the number of ENDBR instructions in the 1857ed53a0d9SPeter Zijlstra kernel image. 1858ed53a0d9SPeter Zijlstra 185935e97790SDave Hansenconfig X86_INTEL_MEMORY_PROTECTION_KEYS 186038f3e775SBabu Moger prompt "Memory Protection Keys" 186135e97790SDave Hansen def_bool y 1862284244a9SDave Hansen # Note: only available in 64-bit mode 186338f3e775SBabu Moger depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 186452c8e601SIngo Molnar select ARCH_USES_HIGH_VMA_FLAGS 186552c8e601SIngo Molnar select ARCH_HAS_PKEYS 1866a7f7f624SMasahiro Yamada help 1867284244a9SDave Hansen Memory Protection Keys provides a mechanism for enforcing 1868284244a9SDave Hansen page-based protections, but without requiring modification of the 1869284244a9SDave Hansen page tables when an application changes protection domains. 1870284244a9SDave Hansen 18711eecbcdcSMauro Carvalho Chehab For details, see Documentation/core-api/protection-keys.rst 1872284244a9SDave Hansen 1873284244a9SDave Hansen If unsure, say y. 187435e97790SDave Hansen 1875db616173SMichal Hockochoice 1876db616173SMichal Hocko prompt "TSX enable mode" 1877db616173SMichal Hocko depends on CPU_SUP_INTEL 1878db616173SMichal Hocko default X86_INTEL_TSX_MODE_OFF 1879db616173SMichal Hocko help 1880db616173SMichal Hocko Intel's TSX (Transactional Synchronization Extensions) feature 1881db616173SMichal Hocko allows to optimize locking protocols through lock elision which 1882db616173SMichal Hocko can lead to a noticeable performance boost. 1883db616173SMichal Hocko 1884db616173SMichal Hocko On the other hand it has been shown that TSX can be exploited 1885db616173SMichal Hocko to form side channel attacks (e.g. TAA) and chances are there 1886db616173SMichal Hocko will be more of those attacks discovered in the future. 1887db616173SMichal Hocko 1888db616173SMichal Hocko Therefore TSX is not enabled by default (aka tsx=off). An admin 1889db616173SMichal Hocko might override this decision by tsx=on the command line parameter. 1890db616173SMichal Hocko Even with TSX enabled, the kernel will attempt to enable the best 1891db616173SMichal Hocko possible TAA mitigation setting depending on the microcode available 1892db616173SMichal Hocko for the particular machine. 1893db616173SMichal Hocko 1894db616173SMichal Hocko This option allows to set the default tsx mode between tsx=on, =off 1895db616173SMichal Hocko and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1896db616173SMichal Hocko details. 1897db616173SMichal Hocko 1898db616173SMichal Hocko Say off if not sure, auto if TSX is in use but it should be used on safe 1899db616173SMichal Hocko platforms or on if TSX is in use and the security aspect of tsx is not 1900db616173SMichal Hocko relevant. 1901db616173SMichal Hocko 1902db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_OFF 1903db616173SMichal Hocko bool "off" 1904db616173SMichal Hocko help 1905db616173SMichal Hocko TSX is disabled if possible - equals to tsx=off command line parameter. 1906db616173SMichal Hocko 1907db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_ON 1908db616173SMichal Hocko bool "on" 1909db616173SMichal Hocko help 1910db616173SMichal Hocko TSX is always enabled on TSX capable HW - equals the tsx=on command 1911db616173SMichal Hocko line parameter. 1912db616173SMichal Hocko 1913db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_AUTO 1914db616173SMichal Hocko bool "auto" 1915db616173SMichal Hocko help 1916db616173SMichal Hocko TSX is enabled on TSX capable HW that is believed to be safe against 1917db616173SMichal Hocko side channel attacks- equals the tsx=auto command line parameter. 1918db616173SMichal Hockoendchoice 1919db616173SMichal Hocko 1920e7e05452SSean Christophersonconfig X86_SGX 1921e7e05452SSean Christopherson bool "Software Guard eXtensions (SGX)" 1922b8d1d163SDaniel Sneddon depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC 1923e7e05452SSean Christopherson depends on CRYPTO=y 1924e7e05452SSean Christopherson depends on CRYPTO_SHA256=y 1925e7e05452SSean Christopherson select MMU_NOTIFIER 1926901ddbb9SJarkko Sakkinen select NUMA_KEEP_MEMINFO if NUMA 192740e0e784STony Luck select XARRAY_MULTI 1928e7e05452SSean Christopherson help 1929e7e05452SSean Christopherson Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1930e7e05452SSean Christopherson that can be used by applications to set aside private regions of code 1931e7e05452SSean Christopherson and data, referred to as enclaves. An enclave's private memory can 1932e7e05452SSean Christopherson only be accessed by code running within the enclave. Accesses from 1933e7e05452SSean Christopherson outside the enclave, including other enclaves, are disallowed by 1934e7e05452SSean Christopherson hardware. 1935e7e05452SSean Christopherson 1936e7e05452SSean Christopherson If unsure, say N. 1937e7e05452SSean Christopherson 193818e66b69SRick Edgecombeconfig X86_USER_SHADOW_STACK 193918e66b69SRick Edgecombe bool "X86 userspace shadow stack" 194018e66b69SRick Edgecombe depends on AS_WRUSS 194118e66b69SRick Edgecombe depends on X86_64 194218e66b69SRick Edgecombe select ARCH_USES_HIGH_VMA_FLAGS 194318e66b69SRick Edgecombe select X86_CET 194418e66b69SRick Edgecombe help 194518e66b69SRick Edgecombe Shadow stack protection is a hardware feature that detects function 194618e66b69SRick Edgecombe return address corruption. This helps mitigate ROP attacks. 194718e66b69SRick Edgecombe Applications must be enabled to use it, and old userspace does not 194818e66b69SRick Edgecombe get protection "for free". 194918e66b69SRick Edgecombe 195018e66b69SRick Edgecombe CPUs supporting shadow stacks were first released in 2020. 195118e66b69SRick Edgecombe 195254acee60SDave Hansen See Documentation/arch/x86/shstk.rst for more information. 195318e66b69SRick Edgecombe 195418e66b69SRick Edgecombe If unsure, say N. 195518e66b69SRick Edgecombe 1956506f1d07SSam Ravnborgconfig EFI 19579ba16087SJan Beulich bool "EFI runtime service support" 19585b83683fSHuang, Ying depends on ACPI 1959f6ce5002SSergey Vlasov select UCS2_STRING 1960022ee6c5SArd Biesheuvel select EFI_RUNTIME_WRAPPERS 19611ff2fc02STom Lendacky select ARCH_USE_MEMREMAP_PROT 1962aba7e066SArd Biesheuvel select EFI_RUNTIME_MAP if KEXEC_CORE 1963a7f7f624SMasahiro Yamada help 19648b2cb7a8SHuang, Ying This enables the kernel to use EFI runtime services that are 1965506f1d07SSam Ravnborg available (such as the EFI variable services). 1966506f1d07SSam Ravnborg 19678b2cb7a8SHuang, Ying This option is only useful on systems that have EFI firmware. 19688b2cb7a8SHuang, Ying In addition, you should use the latest ELILO loader available 19698b2cb7a8SHuang, Ying at <http://elilo.sourceforge.net> in order to take advantage 19708b2cb7a8SHuang, Ying of EFI runtime services. However, even with this option, the 19718b2cb7a8SHuang, Ying resultant kernel should continue to boot on existing non-EFI 19728b2cb7a8SHuang, Ying platforms. 1973506f1d07SSam Ravnborg 1974291f3632SMatt Flemingconfig EFI_STUB 1975291f3632SMatt Fleming bool "EFI stub support" 1976c6dbd3e5SPeter Zijlstra depends on EFI 19777b2a583aSMatt Fleming select RELOCATABLE 1978a7f7f624SMasahiro Yamada help 1979291f3632SMatt Fleming This kernel feature allows a bzImage to be loaded directly 1980291f3632SMatt Fleming by EFI firmware without the use of a bootloader. 1981291f3632SMatt Fleming 19824f4cfa6cSMauro Carvalho Chehab See Documentation/admin-guide/efi-stub.rst for more information. 19830c759662SMatt Fleming 1984cc3fdda2SArd Biesheuvelconfig EFI_HANDOVER_PROTOCOL 1985cc3fdda2SArd Biesheuvel bool "EFI handover protocol (DEPRECATED)" 1986cc3fdda2SArd Biesheuvel depends on EFI_STUB 1987cc3fdda2SArd Biesheuvel default y 1988cc3fdda2SArd Biesheuvel help 1989cc3fdda2SArd Biesheuvel Select this in order to include support for the deprecated EFI 1990cc3fdda2SArd Biesheuvel handover protocol, which defines alternative entry points into the 1991cc3fdda2SArd Biesheuvel EFI stub. This is a practice that has no basis in the UEFI 1992cc3fdda2SArd Biesheuvel specification, and requires a priori knowledge on the part of the 1993cc3fdda2SArd Biesheuvel bootloader about Linux/x86 specific ways of passing the command line 1994cc3fdda2SArd Biesheuvel and initrd, and where in memory those assets may be loaded. 1995cc3fdda2SArd Biesheuvel 1996cc3fdda2SArd Biesheuvel If in doubt, say Y. Even though the corresponding support is not 1997cc3fdda2SArd Biesheuvel present in upstream GRUB or other bootloaders, most distros build 1998cc3fdda2SArd Biesheuvel GRUB with numerous downstream patches applied, and may rely on the 1999cc3fdda2SArd Biesheuvel handover protocol as as result. 2000cc3fdda2SArd Biesheuvel 20017d453eeeSMatt Flemingconfig EFI_MIXED 20027d453eeeSMatt Fleming bool "EFI mixed-mode support" 20037d453eeeSMatt Fleming depends on EFI_STUB && X86_64 2004a7f7f624SMasahiro Yamada help 20057d453eeeSMatt Fleming Enabling this feature allows a 64-bit kernel to be booted 20067d453eeeSMatt Fleming on a 32-bit firmware, provided that your CPU supports 64-bit 20077d453eeeSMatt Fleming mode. 20087d453eeeSMatt Fleming 20097d453eeeSMatt Fleming Note that it is not possible to boot a mixed-mode enabled 20107d453eeeSMatt Fleming kernel via the EFI boot stub - a bootloader that supports 20117d453eeeSMatt Fleming the EFI handover protocol must be used. 20127d453eeeSMatt Fleming 20137d453eeeSMatt Fleming If unsure, say N. 20147d453eeeSMatt Fleming 20154059ba65SArd Biesheuvelconfig EFI_FAKE_MEMMAP 20164059ba65SArd Biesheuvel bool "Enable EFI fake memory map" 20174059ba65SArd Biesheuvel depends on EFI 20184059ba65SArd Biesheuvel help 20194059ba65SArd Biesheuvel Saying Y here will enable "efi_fake_mem" boot option. By specifying 20204059ba65SArd Biesheuvel this parameter, you can add arbitrary attribute to specific memory 20214059ba65SArd Biesheuvel range by updating original (firmware provided) EFI memmap. This is 20224059ba65SArd Biesheuvel useful for debugging of EFI memmap related feature, e.g., Address 20234059ba65SArd Biesheuvel Range Mirroring feature. 20244059ba65SArd Biesheuvel 20254059ba65SArd Biesheuvelconfig EFI_MAX_FAKE_MEM 20264059ba65SArd Biesheuvel int "maximum allowable number of ranges in efi_fake_mem boot option" 20274059ba65SArd Biesheuvel depends on EFI_FAKE_MEMMAP 20284059ba65SArd Biesheuvel range 1 128 20294059ba65SArd Biesheuvel default 8 20304059ba65SArd Biesheuvel help 20314059ba65SArd Biesheuvel Maximum allowable number of ranges in efi_fake_mem boot option. 20324059ba65SArd Biesheuvel Ranges can be set up to this value using comma-separated list. 20334059ba65SArd Biesheuvel The default value is 8. 20344059ba65SArd Biesheuvel 20351fff234dSArd Biesheuvelconfig EFI_RUNTIME_MAP 20361fff234dSArd Biesheuvel bool "Export EFI runtime maps to sysfs" if EXPERT 20371fff234dSArd Biesheuvel depends on EFI 20381fff234dSArd Biesheuvel help 20391fff234dSArd Biesheuvel Export EFI runtime memory regions to /sys/firmware/efi/runtime-map. 20401fff234dSArd Biesheuvel That memory map is required by the 2nd kernel to set up EFI virtual 20411fff234dSArd Biesheuvel mappings after kexec, but can also be used for debugging purposes. 20421fff234dSArd Biesheuvel 20431fff234dSArd Biesheuvel See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map. 20441fff234dSArd Biesheuvel 20458636a1f9SMasahiro Yamadasource "kernel/Kconfig.hz" 2046506f1d07SSam Ravnborg 20476af51380SEric DeVolderconfig ARCH_SUPPORTS_KEXEC 20486af51380SEric DeVolder def_bool y 2049506f1d07SSam Ravnborg 20506af51380SEric DeVolderconfig ARCH_SUPPORTS_KEXEC_FILE 205178422b74SArnd Bergmann def_bool X86_64 2052506f1d07SSam Ravnborg 20536af51380SEric DeVolderconfig ARCH_SELECTS_KEXEC_FILE 20546af51380SEric DeVolder def_bool y 20556af51380SEric DeVolder depends on KEXEC_FILE 2056b69a2afdSJonathan McDowell select HAVE_IMA_KEXEC if IMA 205774ca317cSVivek Goyal 2058e6265fe7SEric DeVolderconfig ARCH_SUPPORTS_KEXEC_PURGATORY 205978422b74SArnd Bergmann def_bool y 2060b799a09fSAKASHI Takahiro 20616af51380SEric DeVolderconfig ARCH_SUPPORTS_KEXEC_SIG 20626af51380SEric DeVolder def_bool y 206399d5cadfSJiri Bohac 20646af51380SEric DeVolderconfig ARCH_SUPPORTS_KEXEC_SIG_FORCE 20656af51380SEric DeVolder def_bool y 206699d5cadfSJiri Bohac 20676af51380SEric DeVolderconfig ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG 20686af51380SEric DeVolder def_bool y 206999d5cadfSJiri Bohac 20706af51380SEric DeVolderconfig ARCH_SUPPORTS_KEXEC_JUMP 20716af51380SEric DeVolder def_bool y 20728e7d8381SVivek Goyal 20736af51380SEric DeVolderconfig ARCH_SUPPORTS_CRASH_DUMP 20746af51380SEric DeVolder def_bool X86_64 || (X86_32 && HIGHMEM) 20758e7d8381SVivek Goyal 2076ea53ad9cSEric DeVolderconfig ARCH_SUPPORTS_CRASH_HOTPLUG 2077ea53ad9cSEric DeVolder def_bool y 20783ab83521SHuang Ying 2079506f1d07SSam Ravnborgconfig PHYSICAL_START 20806a108a14SDavid Rientjes hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2081ceefccc9SH. Peter Anvin default "0x1000000" 2082a7f7f624SMasahiro Yamada help 2083506f1d07SSam Ravnborg This gives the physical address where the kernel is loaded. 2084506f1d07SSam Ravnborg 2085506f1d07SSam Ravnborg If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2086506f1d07SSam Ravnborg bzImage will decompress itself to above physical address and 2087506f1d07SSam Ravnborg run from there. Otherwise, bzImage will run from the address where 2088506f1d07SSam Ravnborg it has been loaded by the boot loader and will ignore above physical 2089506f1d07SSam Ravnborg address. 2090506f1d07SSam Ravnborg 2091506f1d07SSam Ravnborg In normal kdump cases one does not have to set/change this option 2092506f1d07SSam Ravnborg as now bzImage can be compiled as a completely relocatable image 2093506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2094506f1d07SSam Ravnborg address. This option is mainly useful for the folks who don't want 2095506f1d07SSam Ravnborg to use a bzImage for capturing the crash dump and want to use a 2096506f1d07SSam Ravnborg vmlinux instead. vmlinux is not relocatable hence a kernel needs 2097506f1d07SSam Ravnborg to be specifically compiled to run from a specific memory area 2098506f1d07SSam Ravnborg (normally a reserved region) and this option comes handy. 2099506f1d07SSam Ravnborg 2100ceefccc9SH. Peter Anvin So if you are using bzImage for capturing the crash dump, 2101ceefccc9SH. Peter Anvin leave the value here unchanged to 0x1000000 and set 2102ceefccc9SH. Peter Anvin CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2103ceefccc9SH. Peter Anvin for capturing the crash dump change this value to start of 2104ceefccc9SH. Peter Anvin the reserved region. In other words, it can be set based on 2105ceefccc9SH. Peter Anvin the "X" value as specified in the "crashkernel=YM@XM" 2106ceefccc9SH. Peter Anvin command line boot parameter passed to the panic-ed 2107330d4810SMauro Carvalho Chehab kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2108ceefccc9SH. Peter Anvin for more details about crash dumps. 2109506f1d07SSam Ravnborg 2110506f1d07SSam Ravnborg Usage of bzImage for capturing the crash dump is recommended as 2111506f1d07SSam Ravnborg one does not have to build two kernels. Same kernel can be used 2112506f1d07SSam Ravnborg as production kernel and capture kernel. Above option should have 2113506f1d07SSam Ravnborg gone away after relocatable bzImage support is introduced. But it 2114506f1d07SSam Ravnborg is present because there are users out there who continue to use 2115506f1d07SSam Ravnborg vmlinux for dump capture. This option should go away down the 2116506f1d07SSam Ravnborg line. 2117506f1d07SSam Ravnborg 2118506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2119506f1d07SSam Ravnborg 2120506f1d07SSam Ravnborgconfig RELOCATABLE 212126717808SH. Peter Anvin bool "Build a relocatable kernel" 212226717808SH. Peter Anvin default y 2123a7f7f624SMasahiro Yamada help 2124506f1d07SSam Ravnborg This builds a kernel image that retains relocation information 2125506f1d07SSam Ravnborg so it can be loaded someplace besides the default 1MB. 2126506f1d07SSam Ravnborg The relocations tend to make the kernel binary about 10% larger, 2127506f1d07SSam Ravnborg but are discarded at runtime. 2128506f1d07SSam Ravnborg 2129506f1d07SSam Ravnborg One use is for the kexec on panic case where the recovery kernel 2130506f1d07SSam Ravnborg must live at a different physical address than the primary 2131506f1d07SSam Ravnborg kernel. 2132506f1d07SSam Ravnborg 2133506f1d07SSam Ravnborg Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2134506f1d07SSam Ravnborg it has been loaded at and the compile time physical address 21358ab3820fSKees Cook (CONFIG_PHYSICAL_START) is used as the minimum location. 2136506f1d07SSam Ravnborg 21378ab3820fSKees Cookconfig RANDOMIZE_BASE 2138e8581e3dSBaoquan He bool "Randomize the address of the kernel image (KASLR)" 21398ab3820fSKees Cook depends on RELOCATABLE 21406807c846SIngo Molnar default y 2141a7f7f624SMasahiro Yamada help 2142e8581e3dSBaoquan He In support of Kernel Address Space Layout Randomization (KASLR), 2143e8581e3dSBaoquan He this randomizes the physical address at which the kernel image 2144e8581e3dSBaoquan He is decompressed and the virtual address where the kernel 2145e8581e3dSBaoquan He image is mapped, as a security feature that deters exploit 2146e8581e3dSBaoquan He attempts relying on knowledge of the location of kernel 2147e8581e3dSBaoquan He code internals. 2148e8581e3dSBaoquan He 2149ed9f007eSKees Cook On 64-bit, the kernel physical and virtual addresses are 2150ed9f007eSKees Cook randomized separately. The physical address will be anywhere 2151ed9f007eSKees Cook between 16MB and the top of physical memory (up to 64TB). The 2152ed9f007eSKees Cook virtual address will be randomized from 16MB up to 1GB (9 bits 2153ed9f007eSKees Cook of entropy). Note that this also reduces the memory space 2154ed9f007eSKees Cook available to kernel modules from 1.5GB to 1GB. 2155ed9f007eSKees Cook 2156ed9f007eSKees Cook On 32-bit, the kernel physical and virtual addresses are 2157ed9f007eSKees Cook randomized together. They will be randomized from 16MB up to 2158ed9f007eSKees Cook 512MB (8 bits of entropy). 21598ab3820fSKees Cook 2160a653f356SKees Cook Entropy is generated using the RDRAND instruction if it is 2161e8581e3dSBaoquan He supported. If RDTSC is supported, its value is mixed into 2162e8581e3dSBaoquan He the entropy pool as well. If neither RDRAND nor RDTSC are 2163ed9f007eSKees Cook supported, then entropy is read from the i8254 timer. The 2164ed9f007eSKees Cook usable entropy is limited by the kernel being built using 2165ed9f007eSKees Cook 2GB addressing, and that PHYSICAL_ALIGN must be at a 2166ed9f007eSKees Cook minimum of 2MB. As a result, only 10 bits of entropy are 2167ed9f007eSKees Cook theoretically possible, but the implementations are further 2168ed9f007eSKees Cook limited due to memory layouts. 2169e8581e3dSBaoquan He 21706807c846SIngo Molnar If unsure, say Y. 2171da2b6fb9SKees Cook 21728ab3820fSKees Cook# Relocation on x86 needs some additional build support 2173845adf72SH. Peter Anvinconfig X86_NEED_RELOCS 2174845adf72SH. Peter Anvin def_bool y 21758ab3820fSKees Cook depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2176845adf72SH. Peter Anvin 2177506f1d07SSam Ravnborgconfig PHYSICAL_ALIGN 2178a0215061SKees Cook hex "Alignment value to which kernel should be aligned" 21798ab3820fSKees Cook default "0x200000" 2180a0215061SKees Cook range 0x2000 0x1000000 if X86_32 2181a0215061SKees Cook range 0x200000 0x1000000 if X86_64 2182a7f7f624SMasahiro Yamada help 2183506f1d07SSam Ravnborg This value puts the alignment restrictions on physical address 2184506f1d07SSam Ravnborg where kernel is loaded and run from. Kernel is compiled for an 2185506f1d07SSam Ravnborg address which meets above alignment restriction. 2186506f1d07SSam Ravnborg 2187506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2188506f1d07SSam Ravnborg CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2189506f1d07SSam Ravnborg address aligned to above value and run from there. 2190506f1d07SSam Ravnborg 2191506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2192506f1d07SSam Ravnborg CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2193506f1d07SSam Ravnborg load address and decompress itself to the address it has been 2194506f1d07SSam Ravnborg compiled for and run from there. The address for which kernel is 2195506f1d07SSam Ravnborg compiled already meets above alignment restrictions. Hence the 2196506f1d07SSam Ravnborg end result is that kernel runs from a physical address meeting 2197506f1d07SSam Ravnborg above alignment restrictions. 2198506f1d07SSam Ravnborg 2199a0215061SKees Cook On 32-bit this value must be a multiple of 0x2000. On 64-bit 2200a0215061SKees Cook this value must be a multiple of 0x200000. 2201a0215061SKees Cook 2202506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2203506f1d07SSam Ravnborg 2204eedb92abSKirill A. Shutemovconfig DYNAMIC_MEMORY_LAYOUT 2205eedb92abSKirill A. Shutemov bool 2206a7f7f624SMasahiro Yamada help 2207eedb92abSKirill A. Shutemov This option makes base addresses of vmalloc and vmemmap as well as 2208eedb92abSKirill A. Shutemov __PAGE_OFFSET movable during boot. 2209eedb92abSKirill A. Shutemov 22100483e1faSThomas Garnierconfig RANDOMIZE_MEMORY 22110483e1faSThomas Garnier bool "Randomize the kernel memory sections" 22120483e1faSThomas Garnier depends on X86_64 22130483e1faSThomas Garnier depends on RANDOMIZE_BASE 2214eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 22150483e1faSThomas Garnier default RANDOMIZE_BASE 2216a7f7f624SMasahiro Yamada help 22170483e1faSThomas Garnier Randomizes the base virtual address of kernel memory sections 22180483e1faSThomas Garnier (physical memory mapping, vmalloc & vmemmap). This security feature 22190483e1faSThomas Garnier makes exploits relying on predictable memory locations less reliable. 22200483e1faSThomas Garnier 22210483e1faSThomas Garnier The order of allocations remains unchanged. Entropy is generated in 22220483e1faSThomas Garnier the same way as RANDOMIZE_BASE. Current implementation in the optimal 22230483e1faSThomas Garnier configuration have in average 30,000 different possible virtual 22240483e1faSThomas Garnier addresses for each memory section. 22250483e1faSThomas Garnier 22266807c846SIngo Molnar If unsure, say Y. 22270483e1faSThomas Garnier 222890397a41SThomas Garnierconfig RANDOMIZE_MEMORY_PHYSICAL_PADDING 222990397a41SThomas Garnier hex "Physical memory mapping padding" if EXPERT 223090397a41SThomas Garnier depends on RANDOMIZE_MEMORY 223190397a41SThomas Garnier default "0xa" if MEMORY_HOTPLUG 223290397a41SThomas Garnier default "0x0" 223390397a41SThomas Garnier range 0x1 0x40 if MEMORY_HOTPLUG 223490397a41SThomas Garnier range 0x0 0x40 2235a7f7f624SMasahiro Yamada help 223690397a41SThomas Garnier Define the padding in terabytes added to the existing physical 223790397a41SThomas Garnier memory size during kernel memory randomization. It is useful 223890397a41SThomas Garnier for memory hotplug support but reduces the entropy available for 223990397a41SThomas Garnier address randomization. 224090397a41SThomas Garnier 224190397a41SThomas Garnier If unsure, leave at the default value. 224290397a41SThomas Garnier 22436449dcb0SKirill A. Shutemovconfig ADDRESS_MASKING 22446449dcb0SKirill A. Shutemov bool "Linear Address Masking support" 22456449dcb0SKirill A. Shutemov depends on X86_64 224660a5ba56SPawan Gupta depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS 22476449dcb0SKirill A. Shutemov help 22486449dcb0SKirill A. Shutemov Linear Address Masking (LAM) modifies the checking that is applied 22496449dcb0SKirill A. Shutemov to 64-bit linear addresses, allowing software to use of the 22506449dcb0SKirill A. Shutemov untranslated address bits for metadata. 22516449dcb0SKirill A. Shutemov 22526449dcb0SKirill A. Shutemov The capability can be used for efficient address sanitizers (ASAN) 22536449dcb0SKirill A. Shutemov implementation and for optimizations in JITs. 22546449dcb0SKirill A. Shutemov 2255506f1d07SSam Ravnborgconfig HOTPLUG_CPU 2256bebd024eSThomas Gleixner def_bool y 225740b31360SStephen Rothwell depends on SMP 2258506f1d07SSam Ravnborg 2259506f1d07SSam Ravnborgconfig COMPAT_VDSO 2260b0b49f26SAndy Lutomirski def_bool n 2261b0b49f26SAndy Lutomirski prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2262953fee1dSIngo Molnar depends on COMPAT_32 2263a7f7f624SMasahiro Yamada help 2264b0b49f26SAndy Lutomirski Certain buggy versions of glibc will crash if they are 2265b0b49f26SAndy Lutomirski presented with a 32-bit vDSO that is not mapped at the address 2266b0b49f26SAndy Lutomirski indicated in its segment table. 2267e84446deSRandy Dunlap 2268b0b49f26SAndy Lutomirski The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2269b0b49f26SAndy Lutomirski and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2270b0b49f26SAndy Lutomirski 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2271b0b49f26SAndy Lutomirski the only released version with the bug, but OpenSUSE 9 2272b0b49f26SAndy Lutomirski contains a buggy "glibc 2.3.2". 2273506f1d07SSam Ravnborg 2274b0b49f26SAndy Lutomirski The symptom of the bug is that everything crashes on startup, saying: 2275b0b49f26SAndy Lutomirski dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2276b0b49f26SAndy Lutomirski 2277b0b49f26SAndy Lutomirski Saying Y here changes the default value of the vdso32 boot 2278b0b49f26SAndy Lutomirski option from 1 to 0, which turns off the 32-bit vDSO entirely. 2279b0b49f26SAndy Lutomirski This works around the glibc bug but hurts performance. 2280b0b49f26SAndy Lutomirski 2281b0b49f26SAndy Lutomirski If unsure, say N: if you are compiling your own kernel, you 2282b0b49f26SAndy Lutomirski are unlikely to be using a buggy version of glibc. 2283506f1d07SSam Ravnborg 22843dc33bd3SKees Cookchoice 22853dc33bd3SKees Cook prompt "vsyscall table for legacy applications" 22863dc33bd3SKees Cook depends on X86_64 2287625b7b7fSAndy Lutomirski default LEGACY_VSYSCALL_XONLY 22883dc33bd3SKees Cook help 22893dc33bd3SKees Cook Legacy user code that does not know how to find the vDSO expects 22903dc33bd3SKees Cook to be able to issue three syscalls by calling fixed addresses in 22913dc33bd3SKees Cook kernel space. Since this location is not randomized with ASLR, 22923dc33bd3SKees Cook it can be used to assist security vulnerability exploitation. 22933dc33bd3SKees Cook 22943dc33bd3SKees Cook This setting can be changed at boot time via the kernel command 2295bf00745eSAndy Lutomirski line parameter vsyscall=[emulate|xonly|none]. Emulate mode 2296bf00745eSAndy Lutomirski is deprecated and can only be enabled using the kernel command 2297bf00745eSAndy Lutomirski line. 22983dc33bd3SKees Cook 22993dc33bd3SKees Cook On a system with recent enough glibc (2.14 or newer) and no 23003dc33bd3SKees Cook static binaries, you can say None without a performance penalty 23013dc33bd3SKees Cook to improve security. 23023dc33bd3SKees Cook 2303bd49e16eSAndy Lutomirski If unsure, select "Emulate execution only". 23043dc33bd3SKees Cook 2305bd49e16eSAndy Lutomirski config LEGACY_VSYSCALL_XONLY 2306bd49e16eSAndy Lutomirski bool "Emulate execution only" 2307bd49e16eSAndy Lutomirski help 2308bd49e16eSAndy Lutomirski The kernel traps and emulates calls into the fixed vsyscall 2309bd49e16eSAndy Lutomirski address mapping and does not allow reads. This 2310bd49e16eSAndy Lutomirski configuration is recommended when userspace might use the 2311bd49e16eSAndy Lutomirski legacy vsyscall area but support for legacy binary 2312bd49e16eSAndy Lutomirski instrumentation of legacy code is not needed. It mitigates 2313bd49e16eSAndy Lutomirski certain uses of the vsyscall area as an ASLR-bypassing 2314bd49e16eSAndy Lutomirski buffer. 23153dc33bd3SKees Cook 23163dc33bd3SKees Cook config LEGACY_VSYSCALL_NONE 23173dc33bd3SKees Cook bool "None" 23183dc33bd3SKees Cook help 23193dc33bd3SKees Cook There will be no vsyscall mapping at all. This will 23203dc33bd3SKees Cook eliminate any risk of ASLR bypass due to the vsyscall 23213dc33bd3SKees Cook fixed address mapping. Attempts to use the vsyscalls 23223dc33bd3SKees Cook will be reported to dmesg, so that either old or 23233dc33bd3SKees Cook malicious userspace programs can be identified. 23243dc33bd3SKees Cook 23253dc33bd3SKees Cookendchoice 23263dc33bd3SKees Cook 2327516cbf37STim Birdconfig CMDLINE_BOOL 2328516cbf37STim Bird bool "Built-in kernel command line" 2329a7f7f624SMasahiro Yamada help 2330516cbf37STim Bird Allow for specifying boot arguments to the kernel at 2331516cbf37STim Bird build time. On some systems (e.g. embedded ones), it is 2332516cbf37STim Bird necessary or convenient to provide some or all of the 2333516cbf37STim Bird kernel boot arguments with the kernel itself (that is, 2334516cbf37STim Bird to not rely on the boot loader to provide them.) 2335516cbf37STim Bird 2336516cbf37STim Bird To compile command line arguments into the kernel, 2337516cbf37STim Bird set this option to 'Y', then fill in the 233869711ca1SSébastien Hinderer boot arguments in CONFIG_CMDLINE. 2339516cbf37STim Bird 2340516cbf37STim Bird Systems with fully functional boot loaders (i.e. non-embedded) 2341516cbf37STim Bird should leave this option set to 'N'. 2342516cbf37STim Bird 2343516cbf37STim Birdconfig CMDLINE 2344516cbf37STim Bird string "Built-in kernel command string" 2345516cbf37STim Bird depends on CMDLINE_BOOL 2346516cbf37STim Bird default "" 2347a7f7f624SMasahiro Yamada help 2348516cbf37STim Bird Enter arguments here that should be compiled into the kernel 2349516cbf37STim Bird image and used at boot time. If the boot loader provides a 2350516cbf37STim Bird command line at boot time, it is appended to this string to 2351516cbf37STim Bird form the full kernel command line, when the system boots. 2352516cbf37STim Bird 2353516cbf37STim Bird However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2354516cbf37STim Bird change this behavior. 2355516cbf37STim Bird 2356516cbf37STim Bird In most cases, the command line (whether built-in or provided 2357516cbf37STim Bird by the boot loader) should specify the device for the root 2358516cbf37STim Bird file system. 2359516cbf37STim Bird 2360516cbf37STim Birdconfig CMDLINE_OVERRIDE 2361516cbf37STim Bird bool "Built-in command line overrides boot loader arguments" 2362645e6466SAnders Roxell depends on CMDLINE_BOOL && CMDLINE != "" 2363a7f7f624SMasahiro Yamada help 2364516cbf37STim Bird Set this option to 'Y' to have the kernel ignore the boot loader 2365516cbf37STim Bird command line, and use ONLY the built-in command line. 2366516cbf37STim Bird 2367516cbf37STim Bird This is used to work around broken boot loaders. This should 2368516cbf37STim Bird be set to 'N' under normal conditions. 2369516cbf37STim Bird 2370a5b9e5a2SAndy Lutomirskiconfig MODIFY_LDT_SYSCALL 2371a5b9e5a2SAndy Lutomirski bool "Enable the LDT (local descriptor table)" if EXPERT 2372a5b9e5a2SAndy Lutomirski default y 2373a7f7f624SMasahiro Yamada help 2374a5b9e5a2SAndy Lutomirski Linux can allow user programs to install a per-process x86 2375a5b9e5a2SAndy Lutomirski Local Descriptor Table (LDT) using the modify_ldt(2) system 2376a5b9e5a2SAndy Lutomirski call. This is required to run 16-bit or segmented code such as 2377a5b9e5a2SAndy Lutomirski DOSEMU or some Wine programs. It is also used by some very old 2378a5b9e5a2SAndy Lutomirski threading libraries. 2379a5b9e5a2SAndy Lutomirski 2380a5b9e5a2SAndy Lutomirski Enabling this feature adds a small amount of overhead to 2381a5b9e5a2SAndy Lutomirski context switches and increases the low-level kernel attack 2382a5b9e5a2SAndy Lutomirski surface. Disabling it removes the modify_ldt(2) system call. 2383a5b9e5a2SAndy Lutomirski 2384a5b9e5a2SAndy Lutomirski Saying 'N' here may make sense for embedded or server kernels. 2385a5b9e5a2SAndy Lutomirski 23863aac3ebeSThomas Gleixnerconfig STRICT_SIGALTSTACK_SIZE 23873aac3ebeSThomas Gleixner bool "Enforce strict size checking for sigaltstack" 23883aac3ebeSThomas Gleixner depends on DYNAMIC_SIGFRAME 23893aac3ebeSThomas Gleixner help 23903aac3ebeSThomas Gleixner For historical reasons MINSIGSTKSZ is a constant which became 23913aac3ebeSThomas Gleixner already too small with AVX512 support. Add a mechanism to 23923aac3ebeSThomas Gleixner enforce strict checking of the sigaltstack size against the 23933aac3ebeSThomas Gleixner real size of the FPU frame. This option enables the check 23943aac3ebeSThomas Gleixner by default. It can also be controlled via the kernel command 23953aac3ebeSThomas Gleixner line option 'strict_sas_size' independent of this config 23963aac3ebeSThomas Gleixner switch. Enabling it might break existing applications which 23973aac3ebeSThomas Gleixner allocate a too small sigaltstack but 'work' because they 23983aac3ebeSThomas Gleixner never get a signal delivered. 23993aac3ebeSThomas Gleixner 24003aac3ebeSThomas Gleixner Say 'N' unless you want to really enforce this check. 24013aac3ebeSThomas Gleixner 2402b700e7f0SSeth Jenningssource "kernel/livepatch/Kconfig" 2403b700e7f0SSeth Jennings 2404506f1d07SSam Ravnborgendmenu 2405506f1d07SSam Ravnborg 2406f43b9876SPeter Zijlstraconfig CC_HAS_SLS 2407f43b9876SPeter Zijlstra def_bool $(cc-option,-mharden-sls=all) 2408f43b9876SPeter Zijlstra 2409f43b9876SPeter Zijlstraconfig CC_HAS_RETURN_THUNK 2410f43b9876SPeter Zijlstra def_bool $(cc-option,-mfunction-return=thunk-extern) 2411f43b9876SPeter Zijlstra 2412bea75b33SThomas Gleixnerconfig CC_HAS_ENTRY_PADDING 2413bea75b33SThomas Gleixner def_bool $(cc-option,-fpatchable-function-entry=16,16) 2414bea75b33SThomas Gleixner 2415bea75b33SThomas Gleixnerconfig FUNCTION_PADDING_CFI 2416bea75b33SThomas Gleixner int 2417bea75b33SThomas Gleixner default 59 if FUNCTION_ALIGNMENT_64B 2418bea75b33SThomas Gleixner default 27 if FUNCTION_ALIGNMENT_32B 2419bea75b33SThomas Gleixner default 11 if FUNCTION_ALIGNMENT_16B 2420bea75b33SThomas Gleixner default 3 if FUNCTION_ALIGNMENT_8B 2421bea75b33SThomas Gleixner default 0 2422bea75b33SThomas Gleixner 2423bea75b33SThomas Gleixner# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG 2424bea75b33SThomas Gleixner# except Kconfig can't do arithmetic :/ 2425bea75b33SThomas Gleixnerconfig FUNCTION_PADDING_BYTES 2426bea75b33SThomas Gleixner int 2427bea75b33SThomas Gleixner default FUNCTION_PADDING_CFI if CFI_CLANG 2428bea75b33SThomas Gleixner default FUNCTION_ALIGNMENT 2429bea75b33SThomas Gleixner 2430931ab636SPeter Zijlstraconfig CALL_PADDING 2431931ab636SPeter Zijlstra def_bool n 2432931ab636SPeter Zijlstra depends on CC_HAS_ENTRY_PADDING && OBJTOOL 2433931ab636SPeter Zijlstra select FUNCTION_ALIGNMENT_16B 2434931ab636SPeter Zijlstra 2435931ab636SPeter Zijlstraconfig FINEIBT 2436931ab636SPeter Zijlstra def_bool y 2437931ab636SPeter Zijlstra depends on X86_KERNEL_IBT && CFI_CLANG && RETPOLINE 2438931ab636SPeter Zijlstra select CALL_PADDING 2439931ab636SPeter Zijlstra 24408f7c0d8bSThomas Gleixnerconfig HAVE_CALL_THUNKS 24418f7c0d8bSThomas Gleixner def_bool y 2442bea75b33SThomas Gleixner depends on CC_HAS_ENTRY_PADDING && RETHUNK && OBJTOOL 24438f7c0d8bSThomas Gleixner 24448f7c0d8bSThomas Gleixnerconfig CALL_THUNKS 24458f7c0d8bSThomas Gleixner def_bool n 2446931ab636SPeter Zijlstra select CALL_PADDING 24478f7c0d8bSThomas Gleixner 2448b341b20dSPeter Zijlstraconfig PREFIX_SYMBOLS 2449b341b20dSPeter Zijlstra def_bool y 2450931ab636SPeter Zijlstra depends on CALL_PADDING && !CFI_CLANG 2451b341b20dSPeter Zijlstra 24528292f4f8SSean Christophersonmenuconfig CPU_MITIGATIONS 24538292f4f8SSean Christopherson bool "Mitigations for CPU vulnerabilities" 2454f43b9876SPeter Zijlstra default y 2455f43b9876SPeter Zijlstra help 24568292f4f8SSean Christopherson Say Y here to enable options which enable mitigations for hardware 24578292f4f8SSean Christopherson vulnerabilities (usually related to speculative execution). 2458976b74faSSean Christopherson Mitigations can be disabled or restricted to SMT systems at runtime 2459976b74faSSean Christopherson via the "mitigations" kernel parameter. 2460f43b9876SPeter Zijlstra 2461976b74faSSean Christopherson If you say N, all mitigations will be disabled. This CANNOT be 2462976b74faSSean Christopherson overridden at runtime. 2463976b74faSSean Christopherson 2464976b74faSSean Christopherson Say 'Y', unless you really know what you are doing. 2465f43b9876SPeter Zijlstra 24668292f4f8SSean Christophersonif CPU_MITIGATIONS 2467f43b9876SPeter Zijlstra 2468f43b9876SPeter Zijlstraconfig PAGE_TABLE_ISOLATION 2469f43b9876SPeter Zijlstra bool "Remove the kernel mapping in user mode" 2470f43b9876SPeter Zijlstra default y 2471f43b9876SPeter Zijlstra depends on (X86_64 || X86_PAE) 2472f43b9876SPeter Zijlstra help 2473f43b9876SPeter Zijlstra This feature reduces the number of hardware side channels by 2474f43b9876SPeter Zijlstra ensuring that the majority of kernel addresses are not mapped 2475f43b9876SPeter Zijlstra into userspace. 2476f43b9876SPeter Zijlstra 2477ff61f079SJonathan Corbet See Documentation/arch/x86/pti.rst for more details. 2478f43b9876SPeter Zijlstra 2479f43b9876SPeter Zijlstraconfig RETPOLINE 2480f43b9876SPeter Zijlstra bool "Avoid speculative indirect branches in kernel" 2481f43b9876SPeter Zijlstra select OBJTOOL if HAVE_OBJTOOL 2482f43b9876SPeter Zijlstra default y 2483f43b9876SPeter Zijlstra help 2484f43b9876SPeter Zijlstra Compile kernel with the retpoline compiler options to guard against 2485f43b9876SPeter Zijlstra kernel-to-user data leaks by avoiding speculative indirect 2486f43b9876SPeter Zijlstra branches. Requires a compiler with -mindirect-branch=thunk-extern 2487f43b9876SPeter Zijlstra support for full protection. The kernel may run slower. 2488f43b9876SPeter Zijlstra 2489f43b9876SPeter Zijlstraconfig RETHUNK 2490f43b9876SPeter Zijlstra bool "Enable return-thunks" 2491f43b9876SPeter Zijlstra depends on RETPOLINE && CC_HAS_RETURN_THUNK 2492f43b9876SPeter Zijlstra select OBJTOOL if HAVE_OBJTOOL 2493b648ab48SBen Hutchings default y if X86_64 2494f43b9876SPeter Zijlstra help 2495f43b9876SPeter Zijlstra Compile the kernel with the return-thunks compiler option to guard 2496f43b9876SPeter Zijlstra against kernel-to-user data leaks by avoiding return speculation. 2497f43b9876SPeter Zijlstra Requires a compiler with -mfunction-return=thunk-extern 2498f43b9876SPeter Zijlstra support for full protection. The kernel may run slower. 2499f43b9876SPeter Zijlstra 2500f43b9876SPeter Zijlstraconfig CPU_UNRET_ENTRY 2501f43b9876SPeter Zijlstra bool "Enable UNRET on kernel entry" 2502b648ab48SBen Hutchings depends on CPU_SUP_AMD && RETHUNK && X86_64 2503f43b9876SPeter Zijlstra default y 2504f43b9876SPeter Zijlstra help 2505f43b9876SPeter Zijlstra Compile the kernel with support for the retbleed=unret mitigation. 2506f43b9876SPeter Zijlstra 250780e4c1cdSThomas Gleixnerconfig CALL_DEPTH_TRACKING 250880e4c1cdSThomas Gleixner bool "Mitigate RSB underflow with call depth tracking" 250980e4c1cdSThomas Gleixner depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS 251080e4c1cdSThomas Gleixner select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 251180e4c1cdSThomas Gleixner select CALL_THUNKS 251280e4c1cdSThomas Gleixner default y 251380e4c1cdSThomas Gleixner help 251480e4c1cdSThomas Gleixner Compile the kernel with call depth tracking to mitigate the Intel 251580e4c1cdSThomas Gleixner SKL Return-Speculation-Buffer (RSB) underflow issue. The 251680e4c1cdSThomas Gleixner mitigation is off by default and needs to be enabled on the 251780e4c1cdSThomas Gleixner kernel command line via the retbleed=stuff option. For 251880e4c1cdSThomas Gleixner non-affected systems the overhead of this option is marginal as 251980e4c1cdSThomas Gleixner the call depth tracking is using run-time generated call thunks 252080e4c1cdSThomas Gleixner in a compiler generated padding area and call patching. This 252180e4c1cdSThomas Gleixner increases text size by ~5%. For non affected systems this space 252280e4c1cdSThomas Gleixner is unused. On affected SKL systems this results in a significant 252380e4c1cdSThomas Gleixner performance gain over the IBRS mitigation. 252480e4c1cdSThomas Gleixner 2525e81dc127SThomas Gleixnerconfig CALL_THUNKS_DEBUG 2526e81dc127SThomas Gleixner bool "Enable call thunks and call depth tracking debugging" 2527e81dc127SThomas Gleixner depends on CALL_DEPTH_TRACKING 2528e81dc127SThomas Gleixner select FUNCTION_ALIGNMENT_32B 2529e81dc127SThomas Gleixner default n 2530e81dc127SThomas Gleixner help 2531e81dc127SThomas Gleixner Enable call/ret counters for imbalance detection and build in 2532e81dc127SThomas Gleixner a noisy dmesg about callthunks generation and call patching for 2533e81dc127SThomas Gleixner trouble shooting. The debug prints need to be enabled on the 2534e81dc127SThomas Gleixner kernel command line with 'debug-callthunks'. 253554628de6SRandy Dunlap Only enable this when you are debugging call thunks as this 253654628de6SRandy Dunlap creates a noticeable runtime overhead. If unsure say N. 253780e4c1cdSThomas Gleixner 2538f43b9876SPeter Zijlstraconfig CPU_IBPB_ENTRY 2539f43b9876SPeter Zijlstra bool "Enable IBPB on kernel entry" 2540b648ab48SBen Hutchings depends on CPU_SUP_AMD && X86_64 2541f43b9876SPeter Zijlstra default y 2542f43b9876SPeter Zijlstra help 254360ba9b8aSPatrick Bellasi Compile the kernel with support for the retbleed=ibpb and 254460ba9b8aSPatrick Bellasi spec_rstack_overflow={ibpb,ibpb-vmexit} mitigations. 2545f43b9876SPeter Zijlstra 2546f43b9876SPeter Zijlstraconfig CPU_IBRS_ENTRY 2547f43b9876SPeter Zijlstra bool "Enable IBRS on kernel entry" 2548b648ab48SBen Hutchings depends on CPU_SUP_INTEL && X86_64 2549f43b9876SPeter Zijlstra default y 2550f43b9876SPeter Zijlstra help 2551f43b9876SPeter Zijlstra Compile the kernel with support for the spectre_v2=ibrs mitigation. 2552f43b9876SPeter Zijlstra This mitigates both spectre_v2 and retbleed at great cost to 2553f43b9876SPeter Zijlstra performance. 2554f43b9876SPeter Zijlstra 2555fb3bd914SBorislav Petkov (AMD)config CPU_SRSO 2556fb3bd914SBorislav Petkov (AMD) bool "Mitigate speculative RAS overflow on AMD" 2557fb3bd914SBorislav Petkov (AMD) depends on CPU_SUP_AMD && X86_64 && RETHUNK 2558fb3bd914SBorislav Petkov (AMD) default y 2559fb3bd914SBorislav Petkov (AMD) help 2560fb3bd914SBorislav Petkov (AMD) Enable the SRSO mitigation needed on AMD Zen1-4 machines. 2561fb3bd914SBorislav Petkov (AMD) 2562f43b9876SPeter Zijlstraconfig SLS 2563f43b9876SPeter Zijlstra bool "Mitigate Straight-Line-Speculation" 2564f43b9876SPeter Zijlstra depends on CC_HAS_SLS && X86_64 2565f43b9876SPeter Zijlstra select OBJTOOL if HAVE_OBJTOOL 2566f43b9876SPeter Zijlstra default n 2567f43b9876SPeter Zijlstra help 2568f43b9876SPeter Zijlstra Compile the kernel with straight-line-speculation options to guard 2569f43b9876SPeter Zijlstra against straight line speculation. The kernel image might be slightly 2570f43b9876SPeter Zijlstra larger. 2571f43b9876SPeter Zijlstra 257253cf5797SDaniel Sneddonconfig GDS_FORCE_MITIGATION 257353cf5797SDaniel Sneddon bool "Force GDS Mitigation" 257453cf5797SDaniel Sneddon depends on CPU_SUP_INTEL 257553cf5797SDaniel Sneddon default n 257653cf5797SDaniel Sneddon help 257753cf5797SDaniel Sneddon Gather Data Sampling (GDS) is a hardware vulnerability which allows 257853cf5797SDaniel Sneddon unprivileged speculative access to data which was previously stored in 257953cf5797SDaniel Sneddon vector registers. 258053cf5797SDaniel Sneddon 258153cf5797SDaniel Sneddon This option is equivalent to setting gather_data_sampling=force on the 258253cf5797SDaniel Sneddon command line. The microcode mitigation is used if present, otherwise 258353cf5797SDaniel Sneddon AVX is disabled as a mitigation. On affected systems that are missing 258453cf5797SDaniel Sneddon the microcode any userspace code that unconditionally uses AVX will 258553cf5797SDaniel Sneddon break with this option set. 258653cf5797SDaniel Sneddon 258753cf5797SDaniel Sneddon Setting this option on systems not vulnerable to GDS has no effect. 258853cf5797SDaniel Sneddon 258953cf5797SDaniel Sneddon If in doubt, say N. 259053cf5797SDaniel Sneddon 259177018fb9SPawan Guptaconfig MITIGATION_RFDS 259277018fb9SPawan Gupta bool "RFDS Mitigation" 259377018fb9SPawan Gupta depends on CPU_SUP_INTEL 259477018fb9SPawan Gupta default y 259577018fb9SPawan Gupta help 259677018fb9SPawan Gupta Enable mitigation for Register File Data Sampling (RFDS) by default. 259777018fb9SPawan Gupta RFDS is a hardware vulnerability which affects Intel Atom CPUs. It 259877018fb9SPawan Gupta allows unprivileged speculative access to stale data previously 259977018fb9SPawan Gupta stored in floating point, vector and integer registers. 260077018fb9SPawan Gupta See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst> 260177018fb9SPawan Gupta 260209e6cbe9SJosh Poimboeufconfig MITIGATION_SPECTRE_BHI 260309e6cbe9SJosh Poimboeuf bool "Mitigate Spectre-BHB (Branch History Injection)" 2604d414b401SPawan Gupta depends on CPU_SUP_INTEL 260509e6cbe9SJosh Poimboeuf default y 2606d414b401SPawan Gupta help 2607d414b401SPawan Gupta Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks 2608d414b401SPawan Gupta where the branch history buffer is poisoned to speculatively steer 2609d414b401SPawan Gupta indirect branches. 2610d414b401SPawan Gupta See <file:Documentation/admin-guide/hw-vuln/spectre.rst> 2611d414b401SPawan Gupta 2612f43b9876SPeter Zijlstraendif 2613f43b9876SPeter Zijlstra 26143072e413SMichal Hockoconfig ARCH_HAS_ADD_PAGES 26153072e413SMichal Hocko def_bool y 26165c11f00bSDavid Hildenbrand depends on ARCH_ENABLE_MEMORY_HOTPLUG 26173072e413SMichal Hocko 2618da85f865SBjorn Helgaasmenu "Power management and ACPI options" 2619e279b6c1SSam Ravnborg 2620e279b6c1SSam Ravnborgconfig ARCH_HIBERNATION_HEADER 26213c2362e6SHarvey Harrison def_bool y 262244556530SZhimin Gu depends on HIBERNATION 2623e279b6c1SSam Ravnborg 2624e279b6c1SSam Ravnborgsource "kernel/power/Kconfig" 2625e279b6c1SSam Ravnborg 2626e279b6c1SSam Ravnborgsource "drivers/acpi/Kconfig" 2627e279b6c1SSam Ravnborg 2628a6b68076SAndi Kleenconfig X86_APM_BOOT 26296fc108a0SJan Beulich def_bool y 2630282e5aabSPaul Bolle depends on APM 2631a6b68076SAndi Kleen 2632e279b6c1SSam Ravnborgmenuconfig APM 2633e279b6c1SSam Ravnborg tristate "APM (Advanced Power Management) BIOS support" 2634efefa6f6SIngo Molnar depends on X86_32 && PM_SLEEP 2635a7f7f624SMasahiro Yamada help 2636e279b6c1SSam Ravnborg APM is a BIOS specification for saving power using several different 2637e279b6c1SSam Ravnborg techniques. This is mostly useful for battery powered laptops with 2638e279b6c1SSam Ravnborg APM compliant BIOSes. If you say Y here, the system time will be 2639e279b6c1SSam Ravnborg reset after a RESUME operation, the /proc/apm device will provide 2640e279b6c1SSam Ravnborg battery status information, and user-space programs will receive 2641e279b6c1SSam Ravnborg notification of APM "events" (e.g. battery status change). 2642e279b6c1SSam Ravnborg 2643e279b6c1SSam Ravnborg If you select "Y" here, you can disable actual use of the APM 2644e279b6c1SSam Ravnborg BIOS by passing the "apm=off" option to the kernel at boot time. 2645e279b6c1SSam Ravnborg 2646e279b6c1SSam Ravnborg Note that the APM support is almost completely disabled for 2647e279b6c1SSam Ravnborg machines with more than one CPU. 2648e279b6c1SSam Ravnborg 2649e279b6c1SSam Ravnborg In order to use APM, you will need supporting software. For location 2650151f4e2bSMauro Carvalho Chehab and more information, read <file:Documentation/power/apm-acpi.rst> 26512dc98fd3SMichael Witten and the Battery Powered Linux mini-HOWTO, available from 2652e279b6c1SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 2653e279b6c1SSam Ravnborg 2654e279b6c1SSam Ravnborg This driver does not spin down disk drives (see the hdparm(8) 2655e279b6c1SSam Ravnborg manpage ("man 8 hdparm") for that), and it doesn't turn off 2656e279b6c1SSam Ravnborg VESA-compliant "green" monitors. 2657e279b6c1SSam Ravnborg 2658e279b6c1SSam Ravnborg This driver does not support the TI 4000M TravelMate and the ACER 2659e279b6c1SSam Ravnborg 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2660e279b6c1SSam Ravnborg desktop machines also don't have compliant BIOSes, and this driver 2661e279b6c1SSam Ravnborg may cause those machines to panic during the boot phase. 2662e279b6c1SSam Ravnborg 2663e279b6c1SSam Ravnborg Generally, if you don't have a battery in your machine, there isn't 2664e279b6c1SSam Ravnborg much point in using this driver and you should say N. If you get 2665e279b6c1SSam Ravnborg random kernel OOPSes or reboots that don't seem to be related to 2666e279b6c1SSam Ravnborg anything, try disabling/enabling this option (or disabling/enabling 2667e279b6c1SSam Ravnborg APM in your BIOS). 2668e279b6c1SSam Ravnborg 2669e279b6c1SSam Ravnborg Some other things you should try when experiencing seemingly random, 2670e279b6c1SSam Ravnborg "weird" problems: 2671e279b6c1SSam Ravnborg 2672e279b6c1SSam Ravnborg 1) make sure that you have enough swap space and that it is 2673e279b6c1SSam Ravnborg enabled. 26747987448fSStephen Kitt 2) pass the "idle=poll" option to the kernel 2675e279b6c1SSam Ravnborg 3) switch on floating point emulation in the kernel and pass 2676e279b6c1SSam Ravnborg the "no387" option to the kernel 2677e279b6c1SSam Ravnborg 4) pass the "floppy=nodma" option to the kernel 2678e279b6c1SSam Ravnborg 5) pass the "mem=4M" option to the kernel (thereby disabling 2679e279b6c1SSam Ravnborg all but the first 4 MB of RAM) 2680e279b6c1SSam Ravnborg 6) make sure that the CPU is not over clocked. 2681e279b6c1SSam Ravnborg 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2682e279b6c1SSam Ravnborg 8) disable the cache from your BIOS settings 2683e279b6c1SSam Ravnborg 9) install a fan for the video card or exchange video RAM 2684e279b6c1SSam Ravnborg 10) install a better fan for the CPU 2685e279b6c1SSam Ravnborg 11) exchange RAM chips 2686e279b6c1SSam Ravnborg 12) exchange the motherboard. 2687e279b6c1SSam Ravnborg 2688e279b6c1SSam Ravnborg To compile this driver as a module, choose M here: the 2689e279b6c1SSam Ravnborg module will be called apm. 2690e279b6c1SSam Ravnborg 2691e279b6c1SSam Ravnborgif APM 2692e279b6c1SSam Ravnborg 2693e279b6c1SSam Ravnborgconfig APM_IGNORE_USER_SUSPEND 2694e279b6c1SSam Ravnborg bool "Ignore USER SUSPEND" 2695a7f7f624SMasahiro Yamada help 2696e279b6c1SSam Ravnborg This option will ignore USER SUSPEND requests. On machines with a 2697e279b6c1SSam Ravnborg compliant APM BIOS, you want to say N. However, on the NEC Versa M 2698e279b6c1SSam Ravnborg series notebooks, it is necessary to say Y because of a BIOS bug. 2699e279b6c1SSam Ravnborg 2700e279b6c1SSam Ravnborgconfig APM_DO_ENABLE 2701e279b6c1SSam Ravnborg bool "Enable PM at boot time" 2702a7f7f624SMasahiro Yamada help 2703e279b6c1SSam Ravnborg Enable APM features at boot time. From page 36 of the APM BIOS 2704e279b6c1SSam Ravnborg specification: "When disabled, the APM BIOS does not automatically 2705e279b6c1SSam Ravnborg power manage devices, enter the Standby State, enter the Suspend 2706e279b6c1SSam Ravnborg State, or take power saving steps in response to CPU Idle calls." 2707e279b6c1SSam Ravnborg This driver will make CPU Idle calls when Linux is idle (unless this 2708e279b6c1SSam Ravnborg feature is turned off -- see "Do CPU IDLE calls", below). This 2709e279b6c1SSam Ravnborg should always save battery power, but more complicated APM features 2710e279b6c1SSam Ravnborg will be dependent on your BIOS implementation. You may need to turn 2711e279b6c1SSam Ravnborg this option off if your computer hangs at boot time when using APM 2712e279b6c1SSam Ravnborg support, or if it beeps continuously instead of suspending. Turn 2713e279b6c1SSam Ravnborg this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2714e279b6c1SSam Ravnborg T400CDT. This is off by default since most machines do fine without 2715e279b6c1SSam Ravnborg this feature. 2716e279b6c1SSam Ravnborg 2717e279b6c1SSam Ravnborgconfig APM_CPU_IDLE 2718dd8af076SLen Brown depends on CPU_IDLE 2719e279b6c1SSam Ravnborg bool "Make CPU Idle calls when idle" 2720a7f7f624SMasahiro Yamada help 2721e279b6c1SSam Ravnborg Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2722e279b6c1SSam Ravnborg On some machines, this can activate improved power savings, such as 2723e279b6c1SSam Ravnborg a slowed CPU clock rate, when the machine is idle. These idle calls 2724e279b6c1SSam Ravnborg are made after the idle loop has run for some length of time (e.g., 2725e279b6c1SSam Ravnborg 333 mS). On some machines, this will cause a hang at boot time or 2726e279b6c1SSam Ravnborg whenever the CPU becomes idle. (On machines with more than one CPU, 2727e279b6c1SSam Ravnborg this option does nothing.) 2728e279b6c1SSam Ravnborg 2729e279b6c1SSam Ravnborgconfig APM_DISPLAY_BLANK 2730e279b6c1SSam Ravnborg bool "Enable console blanking using APM" 2731a7f7f624SMasahiro Yamada help 2732e279b6c1SSam Ravnborg Enable console blanking using the APM. Some laptops can use this to 2733e279b6c1SSam Ravnborg turn off the LCD backlight when the screen blanker of the Linux 2734e279b6c1SSam Ravnborg virtual console blanks the screen. Note that this is only used by 2735e279b6c1SSam Ravnborg the virtual console screen blanker, and won't turn off the backlight 2736e279b6c1SSam Ravnborg when using the X Window system. This also doesn't have anything to 2737e279b6c1SSam Ravnborg do with your VESA-compliant power-saving monitor. Further, this 2738e279b6c1SSam Ravnborg option doesn't work for all laptops -- it might not turn off your 2739e279b6c1SSam Ravnborg backlight at all, or it might print a lot of errors to the console, 2740e279b6c1SSam Ravnborg especially if you are using gpm. 2741e279b6c1SSam Ravnborg 2742e279b6c1SSam Ravnborgconfig APM_ALLOW_INTS 2743e279b6c1SSam Ravnborg bool "Allow interrupts during APM BIOS calls" 2744a7f7f624SMasahiro Yamada help 2745e279b6c1SSam Ravnborg Normally we disable external interrupts while we are making calls to 2746e279b6c1SSam Ravnborg the APM BIOS as a measure to lessen the effects of a badly behaving 2747e279b6c1SSam Ravnborg BIOS implementation. The BIOS should reenable interrupts if it 2748e279b6c1SSam Ravnborg needs to. Unfortunately, some BIOSes do not -- especially those in 2749e279b6c1SSam Ravnborg many of the newer IBM Thinkpads. If you experience hangs when you 2750e279b6c1SSam Ravnborg suspend, try setting this to Y. Otherwise, say N. 2751e279b6c1SSam Ravnborg 2752e279b6c1SSam Ravnborgendif # APM 2753e279b6c1SSam Ravnborg 2754bb0a56ecSDave Jonessource "drivers/cpufreq/Kconfig" 2755e279b6c1SSam Ravnborg 2756e279b6c1SSam Ravnborgsource "drivers/cpuidle/Kconfig" 2757e279b6c1SSam Ravnborg 275827471fdbSAndy Henroidsource "drivers/idle/Kconfig" 275927471fdbSAndy Henroid 2760e279b6c1SSam Ravnborgendmenu 2761e279b6c1SSam Ravnborg 2762e279b6c1SSam Ravnborgmenu "Bus options (PCI etc.)" 2763e279b6c1SSam Ravnborg 2764e279b6c1SSam Ravnborgchoice 2765e279b6c1SSam Ravnborg prompt "PCI access mode" 2766efefa6f6SIngo Molnar depends on X86_32 && PCI 2767e279b6c1SSam Ravnborg default PCI_GOANY 2768a7f7f624SMasahiro Yamada help 2769e279b6c1SSam Ravnborg On PCI systems, the BIOS can be used to detect the PCI devices and 2770e279b6c1SSam Ravnborg determine their configuration. However, some old PCI motherboards 2771e279b6c1SSam Ravnborg have BIOS bugs and may crash if this is done. Also, some embedded 2772e279b6c1SSam Ravnborg PCI-based systems don't have any BIOS at all. Linux can also try to 2773e279b6c1SSam Ravnborg detect the PCI hardware directly without using the BIOS. 2774e279b6c1SSam Ravnborg 2775e279b6c1SSam Ravnborg With this option, you can specify how Linux should detect the 2776e279b6c1SSam Ravnborg PCI devices. If you choose "BIOS", the BIOS will be used, 2777e279b6c1SSam Ravnborg if you choose "Direct", the BIOS won't be used, and if you 2778e279b6c1SSam Ravnborg choose "MMConfig", then PCI Express MMCONFIG will be used. 2779e279b6c1SSam Ravnborg If you choose "Any", the kernel will try MMCONFIG, then the 2780e279b6c1SSam Ravnborg direct access method and falls back to the BIOS if that doesn't 2781e279b6c1SSam Ravnborg work. If unsure, go with the default, which is "Any". 2782e279b6c1SSam Ravnborg 2783e279b6c1SSam Ravnborgconfig PCI_GOBIOS 2784e279b6c1SSam Ravnborg bool "BIOS" 2785e279b6c1SSam Ravnborg 2786e279b6c1SSam Ravnborgconfig PCI_GOMMCONFIG 2787e279b6c1SSam Ravnborg bool "MMConfig" 2788e279b6c1SSam Ravnborg 2789e279b6c1SSam Ravnborgconfig PCI_GODIRECT 2790e279b6c1SSam Ravnborg bool "Direct" 2791e279b6c1SSam Ravnborg 27923ef0e1f8SAndres Salomonconfig PCI_GOOLPC 279376fb6570SDaniel Drake bool "OLPC XO-1" 27943ef0e1f8SAndres Salomon depends on OLPC 27953ef0e1f8SAndres Salomon 27962bdd1b03SAndres Salomonconfig PCI_GOANY 27972bdd1b03SAndres Salomon bool "Any" 27982bdd1b03SAndres Salomon 2799e279b6c1SSam Ravnborgendchoice 2800e279b6c1SSam Ravnborg 2801e279b6c1SSam Ravnborgconfig PCI_BIOS 28023c2362e6SHarvey Harrison def_bool y 2803efefa6f6SIngo Molnar depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2804e279b6c1SSam Ravnborg 2805e279b6c1SSam Ravnborg# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2806e279b6c1SSam Ravnborgconfig PCI_DIRECT 28073c2362e6SHarvey Harrison def_bool y 28080aba496fSShaohua Li depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2809e279b6c1SSam Ravnborg 2810e279b6c1SSam Ravnborgconfig PCI_MMCONFIG 2811b45c9f36SJan Kiszka bool "Support mmconfig PCI config space access" if X86_64 2812b45c9f36SJan Kiszka default y 28134590d98fSAndy Shevchenko depends on PCI && (ACPI || JAILHOUSE_GUEST) 2814b45c9f36SJan Kiszka depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2815e279b6c1SSam Ravnborg 28163ef0e1f8SAndres Salomonconfig PCI_OLPC 28172bdd1b03SAndres Salomon def_bool y 28182bdd1b03SAndres Salomon depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 28193ef0e1f8SAndres Salomon 2820b5401a96SAlex Nixonconfig PCI_XEN 2821b5401a96SAlex Nixon def_bool y 2822b5401a96SAlex Nixon depends on PCI && XEN 2823b5401a96SAlex Nixon 28248364e1f8SJan Kiszkaconfig MMCONF_FAM10H 28258364e1f8SJan Kiszka def_bool y 28268364e1f8SJan Kiszka depends on X86_64 && PCI_MMCONFIG && ACPI 2827e279b6c1SSam Ravnborg 28283f6ea84aSIra W. Snyderconfig PCI_CNB20LE_QUIRK 28296a108a14SDavid Rientjes bool "Read CNB20LE Host Bridge Windows" if EXPERT 28306ea30386SKees Cook depends on PCI 28313f6ea84aSIra W. Snyder help 28323f6ea84aSIra W. Snyder Read the PCI windows out of the CNB20LE host bridge. This allows 28333f6ea84aSIra W. Snyder PCI hotplug to work on systems with the CNB20LE chipset which do 28343f6ea84aSIra W. Snyder not have ACPI. 28353f6ea84aSIra W. Snyder 283664a5fed6SBjorn Helgaas There's no public spec for this chipset, and this functionality 283764a5fed6SBjorn Helgaas is known to be incomplete. 283864a5fed6SBjorn Helgaas 283964a5fed6SBjorn Helgaas You should say N unless you know you need this. 284064a5fed6SBjorn Helgaas 28413a495511SWilliam Breathitt Grayconfig ISA_BUS 284217a2a129SWilliam Breathitt Gray bool "ISA bus support on modern systems" if EXPERT 28433a495511SWilliam Breathitt Gray help 284417a2a129SWilliam Breathitt Gray Expose ISA bus device drivers and options available for selection and 284517a2a129SWilliam Breathitt Gray configuration. Enable this option if your target machine has an ISA 284617a2a129SWilliam Breathitt Gray bus. ISA is an older system, displaced by PCI and newer bus 284717a2a129SWilliam Breathitt Gray architectures -- if your target machine is modern, it probably does 284817a2a129SWilliam Breathitt Gray not have an ISA bus. 28493a495511SWilliam Breathitt Gray 28503a495511SWilliam Breathitt Gray If unsure, say N. 28513a495511SWilliam Breathitt Gray 28521c00f016SDavid Rientjes# x86_64 have no ISA slots, but can have ISA-style DMA. 2853e279b6c1SSam Ravnborgconfig ISA_DMA_API 28541c00f016SDavid Rientjes bool "ISA-style DMA support" if (X86_64 && EXPERT) 28551c00f016SDavid Rientjes default y 28561c00f016SDavid Rientjes help 28571c00f016SDavid Rientjes Enables ISA-style DMA support for devices requiring such controllers. 28581c00f016SDavid Rientjes If unsure, say Y. 2859e279b6c1SSam Ravnborg 286051e68d05SLinus Torvaldsif X86_32 286151e68d05SLinus Torvalds 2862e279b6c1SSam Ravnborgconfig ISA 2863e279b6c1SSam Ravnborg bool "ISA support" 2864a7f7f624SMasahiro Yamada help 2865e279b6c1SSam Ravnborg Find out whether you have ISA slots on your motherboard. ISA is the 2866e279b6c1SSam Ravnborg name of a bus system, i.e. the way the CPU talks to the other stuff 2867e279b6c1SSam Ravnborg inside your box. Other bus systems are PCI, EISA, MicroChannel 2868e279b6c1SSam Ravnborg (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2869e279b6c1SSam Ravnborg newer boards don't support it. If you have ISA, say Y, otherwise N. 2870e279b6c1SSam Ravnborg 2871e279b6c1SSam Ravnborgconfig SCx200 2872e279b6c1SSam Ravnborg tristate "NatSemi SCx200 support" 2873a7f7f624SMasahiro Yamada help 2874e279b6c1SSam Ravnborg This provides basic support for National Semiconductor's 2875e279b6c1SSam Ravnborg (now AMD's) Geode processors. The driver probes for the 2876e279b6c1SSam Ravnborg PCI-IDs of several on-chip devices, so its a good dependency 2877e279b6c1SSam Ravnborg for other scx200_* drivers. 2878e279b6c1SSam Ravnborg 2879e279b6c1SSam Ravnborg If compiled as a module, the driver is named scx200. 2880e279b6c1SSam Ravnborg 2881e279b6c1SSam Ravnborgconfig SCx200HR_TIMER 2882e279b6c1SSam Ravnborg tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2883592913ecSJohn Stultz depends on SCx200 2884e279b6c1SSam Ravnborg default y 2885a7f7f624SMasahiro Yamada help 2886e279b6c1SSam Ravnborg This driver provides a clocksource built upon the on-chip 2887e279b6c1SSam Ravnborg 27MHz high-resolution timer. Its also a workaround for 2888e279b6c1SSam Ravnborg NSC Geode SC-1100's buggy TSC, which loses time when the 2889e279b6c1SSam Ravnborg processor goes idle (as is done by the scheduler). The 2890e279b6c1SSam Ravnborg other workaround is idle=poll boot option. 2891e279b6c1SSam Ravnborg 28923ef0e1f8SAndres Salomonconfig OLPC 28933ef0e1f8SAndres Salomon bool "One Laptop Per Child support" 289454008979SThomas Gleixner depends on !X86_PAE 28953c554946SAndres Salomon select GPIOLIB 2896dc3119e7SThomas Gleixner select OF 289745bb1674SDaniel Drake select OF_PROMTREE 2898b4e51854SGrant Likely select IRQ_DOMAIN 28990c3d931bSLubomir Rintel select OLPC_EC 2900a7f7f624SMasahiro Yamada help 29013ef0e1f8SAndres Salomon Add support for detecting the unique features of the OLPC 29023ef0e1f8SAndres Salomon XO hardware. 29033ef0e1f8SAndres Salomon 2904a3128588SDaniel Drakeconfig OLPC_XO1_PM 2905a3128588SDaniel Drake bool "OLPC XO-1 Power Management" 2906fa112cf1SBorislav Petkov depends on OLPC && MFD_CS5535=y && PM_SLEEP 2907a7f7f624SMasahiro Yamada help 290897c4cb71SDaniel Drake Add support for poweroff and suspend of the OLPC XO-1 laptop. 2909bf1ebf00SDaniel Drake 2910cfee9597SDaniel Drakeconfig OLPC_XO1_RTC 2911cfee9597SDaniel Drake bool "OLPC XO-1 Real Time Clock" 2912cfee9597SDaniel Drake depends on OLPC_XO1_PM && RTC_DRV_CMOS 2913a7f7f624SMasahiro Yamada help 2914cfee9597SDaniel Drake Add support for the XO-1 real time clock, which can be used as a 2915cfee9597SDaniel Drake programmable wakeup source. 2916cfee9597SDaniel Drake 29177feda8e9SDaniel Drakeconfig OLPC_XO1_SCI 29187feda8e9SDaniel Drake bool "OLPC XO-1 SCI extras" 291992e830f2SArnd Bergmann depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2920ed8e47feSRandy Dunlap depends on INPUT=y 2921d8d01a63SDaniel Drake select POWER_SUPPLY 2922a7f7f624SMasahiro Yamada help 29237feda8e9SDaniel Drake Add support for SCI-based features of the OLPC XO-1 laptop: 29247bc74b3dSDaniel Drake - EC-driven system wakeups 29257feda8e9SDaniel Drake - Power button 29267bc74b3dSDaniel Drake - Ebook switch 29272cf2baeaSDaniel Drake - Lid switch 2928e1040ac6SDaniel Drake - AC adapter status updates 2929e1040ac6SDaniel Drake - Battery status updates 29307feda8e9SDaniel Drake 2931a0f30f59SDaniel Drakeconfig OLPC_XO15_SCI 2932a0f30f59SDaniel Drake bool "OLPC XO-1.5 SCI extras" 2933d8d01a63SDaniel Drake depends on OLPC && ACPI 2934d8d01a63SDaniel Drake select POWER_SUPPLY 2935a7f7f624SMasahiro Yamada help 2936a0f30f59SDaniel Drake Add support for SCI-based features of the OLPC XO-1.5 laptop: 2937a0f30f59SDaniel Drake - EC-driven system wakeups 2938a0f30f59SDaniel Drake - AC adapter status updates 2939a0f30f59SDaniel Drake - Battery status updates 2940e279b6c1SSam Ravnborg 2941d4f3e350SEd Wildgooseconfig ALIX 2942d4f3e350SEd Wildgoose bool "PCEngines ALIX System Support (LED setup)" 2943d4f3e350SEd Wildgoose select GPIOLIB 2944a7f7f624SMasahiro Yamada help 2945d4f3e350SEd Wildgoose This option enables system support for the PCEngines ALIX. 2946d4f3e350SEd Wildgoose At present this just sets up LEDs for GPIO control on 2947d4f3e350SEd Wildgoose ALIX2/3/6 boards. However, other system specific setup should 2948d4f3e350SEd Wildgoose get added here. 2949d4f3e350SEd Wildgoose 2950d4f3e350SEd Wildgoose Note: You must still enable the drivers for GPIO and LED support 2951d4f3e350SEd Wildgoose (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2952d4f3e350SEd Wildgoose 2953d4f3e350SEd Wildgoose Note: You have to set alix.force=1 for boards with Award BIOS. 2954d4f3e350SEd Wildgoose 2955da4e3302SPhilip Prindevilleconfig NET5501 2956da4e3302SPhilip Prindeville bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2957da4e3302SPhilip Prindeville select GPIOLIB 2958a7f7f624SMasahiro Yamada help 2959da4e3302SPhilip Prindeville This option enables system support for the Soekris Engineering net5501. 2960da4e3302SPhilip Prindeville 29613197059aSPhilip A. Prindevilleconfig GEOS 29623197059aSPhilip A. Prindeville bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 29633197059aSPhilip A. Prindeville select GPIOLIB 29643197059aSPhilip A. Prindeville depends on DMI 2965a7f7f624SMasahiro Yamada help 29663197059aSPhilip A. Prindeville This option enables system support for the Traverse Technologies GEOS. 29673197059aSPhilip A. Prindeville 29687d029125SVivien Didelotconfig TS5500 29697d029125SVivien Didelot bool "Technologic Systems TS-5500 platform support" 29707d029125SVivien Didelot depends on MELAN 29717d029125SVivien Didelot select CHECK_SIGNATURE 29727d029125SVivien Didelot select NEW_LEDS 29737d029125SVivien Didelot select LEDS_CLASS 2974a7f7f624SMasahiro Yamada help 29757d029125SVivien Didelot This option enables system support for the Technologic Systems TS-5500. 29767d029125SVivien Didelot 2977e279b6c1SSam Ravnborgendif # X86_32 2978e279b6c1SSam Ravnborg 297923ac4ae8SAndreas Herrmannconfig AMD_NB 2980e279b6c1SSam Ravnborg def_bool y 29810e152cd7SBorislav Petkov depends on CPU_SUP_AMD && PCI 2982e279b6c1SSam Ravnborg 2983e279b6c1SSam Ravnborgendmenu 2984e279b6c1SSam Ravnborg 29851572497cSChristoph Hellwigmenu "Binary Emulations" 2986e279b6c1SSam Ravnborg 2987e279b6c1SSam Ravnborgconfig IA32_EMULATION 2988e279b6c1SSam Ravnborg bool "IA32 Emulation" 2989e279b6c1SSam Ravnborg depends on X86_64 299039f88911SIngo Molnar select ARCH_WANT_OLD_COMPAT_IPC 2991d1603990SRandy Dunlap select BINFMT_ELF 299239f88911SIngo Molnar select COMPAT_OLD_SIGACTION 2993a7f7f624SMasahiro Yamada help 29945fd92e65SH. J. Lu Include code to run legacy 32-bit programs under a 29955fd92e65SH. J. Lu 64-bit kernel. You should likely turn this on, unless you're 29965fd92e65SH. J. Lu 100% sure that you don't have any 32-bit programs left. 2997e279b6c1SSam Ravnborg 299883a44a4fSMasahiro Yamadaconfig X86_X32_ABI 29996ea30386SKees Cook bool "x32 ABI for 64-bit mode" 30009b54050bSBrian Gerst depends on X86_64 3001aaeed6ecSNathan Chancellor # llvm-objcopy does not convert x86_64 .note.gnu.property or 3002aaeed6ecSNathan Chancellor # compressed debug sections to x86_x32 properly: 3003aaeed6ecSNathan Chancellor # https://github.com/ClangBuiltLinux/linux/issues/514 3004aaeed6ecSNathan Chancellor # https://github.com/ClangBuiltLinux/linux/issues/1141 3005aaeed6ecSNathan Chancellor depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm) 3006a7f7f624SMasahiro Yamada help 30075fd92e65SH. J. Lu Include code to run binaries for the x32 native 32-bit ABI 30085fd92e65SH. J. Lu for 64-bit processors. An x32 process gets access to the 30095fd92e65SH. J. Lu full 64-bit register file and wide data path while leaving 30105fd92e65SH. J. Lu pointers at 32 bits for smaller memory footprint. 30115fd92e65SH. J. Lu 3012953fee1dSIngo Molnarconfig COMPAT_32 3013953fee1dSIngo Molnar def_bool y 3014953fee1dSIngo Molnar depends on IA32_EMULATION || X86_32 3015953fee1dSIngo Molnar select HAVE_UID16 3016953fee1dSIngo Molnar select OLD_SIGSUSPEND3 3017953fee1dSIngo Molnar 3018e279b6c1SSam Ravnborgconfig COMPAT 30193c2362e6SHarvey Harrison def_bool y 302083a44a4fSMasahiro Yamada depends on IA32_EMULATION || X86_X32_ABI 3021e279b6c1SSam Ravnborg 3022e279b6c1SSam Ravnborgconfig COMPAT_FOR_U64_ALIGNMENT 30233120e25eSJan Beulich def_bool y 3024a9251280SLinus Torvalds depends on COMPAT 3025ee009e4aSDavid Howells 3026e279b6c1SSam Ravnborgendmenu 3027e279b6c1SSam Ravnborg 3028e5beae16SKeith Packardconfig HAVE_ATOMIC_IOMAP 3029e5beae16SKeith Packard def_bool y 3030e5beae16SKeith Packard depends on X86_32 3031e5beae16SKeith Packard 3032edf88417SAvi Kivitysource "arch/x86/kvm/Kconfig" 30335e8ebd84SJason A. Donenfeld 30345e8ebd84SJason A. Donenfeldsource "arch/x86/Kconfig.assembler" 3035