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 651f6d3a8fSMasami Hiramatsu select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 661e866974SAnshuman Khandual select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION 675c11f00bSDavid Hildenbrand select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64 6891024b3cSAnshuman Khandual select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG 69cebc774fSAnshuman Khandual select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE) 701e866974SAnshuman Khandual select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE 7191dda51aSAleksey Makarov select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 72c2280be8SAnshuman Khandual select ARCH_HAS_CACHE_LINE_SIZE 731156b441SDavidlohr Bueso select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION 747c7077a7SThomas Gleixner select ARCH_HAS_CPU_FINALIZE_INIT 752792d84eSKees Cook select ARCH_HAS_CURRENT_STACK_POINTER 76fa5b6ec9SLaura Abbott select ARCH_HAS_DEBUG_VIRTUAL 77399145f9SAnshuman Khandual select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 7821266be9SDan Williams select ARCH_HAS_DEVMEM_IS_ALLOWED 79b1a57bbfSDouglas Anderson select ARCH_HAS_EARLY_DEBUG if KGDB 806471b825SIngo Molnar select ARCH_HAS_ELF_RANDOMIZE 8172d93104SLinus Torvalds select ARCH_HAS_FAST_MULTIPLIER 826974f0c4SDaniel Micay select ARCH_HAS_FORTIFY_SOURCE 83957e3facSRiku Voipio select ARCH_HAS_GCOV_PROFILE_ALL 84bece04b5SMarco Elver select ARCH_HAS_KCOV if X86_64 850c9c1d56SThiago Jung Bauermann select ARCH_HAS_MEM_ENCRYPT 8610bcc80eSMathieu Desnoyers select ARCH_HAS_MEMBARRIER_SYNC_CORE 8749f88c70SPaul E. McKenney select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS 880ebeea8cSDaniel Borkmann select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 89c763ea26SIngo Molnar select ARCH_HAS_PMEM_API if X86_64 9017596731SRobin Murphy select ARCH_HAS_PTE_DEVMAP if X86_64 913010a5eaSLaurent Dufour select ARCH_HAS_PTE_SPECIAL 92eed9a328SYu Zhao select ARCH_HAS_NONLEAF_PMD_YOUNG if PGTABLE_LEVELS > 2 930aed55afSDan Williams select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 94ec6347bbSDan Williams select ARCH_HAS_COPY_MC if X86_64 95d2852a22SDaniel Borkmann select ARCH_HAS_SET_MEMORY 96d253ca0cSRick Edgecombe select ARCH_HAS_SET_DIRECT_MAP 97ad21fc4fSLaura Abbott select ARCH_HAS_STRICT_KERNEL_RWX 98ad21fc4fSLaura Abbott select ARCH_HAS_STRICT_MODULE_RWX 99ac1ab12aSMathieu Desnoyers select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 10025c619e5SBrian Gerst select ARCH_HAS_SYSCALL_WRAPPER 101c6d30853SAndrey Ryabinin select ARCH_HAS_UBSAN_SANITIZE_ALL 1027e01ccb4SZong Li select ARCH_HAS_DEBUG_WX 10363703f37SKefeng Wang select ARCH_HAS_ZONE_DMA_SET if EXPERT 1046471b825SIngo Molnar select ARCH_HAVE_NMI_SAFE_CMPXCHG 1056471b825SIngo Molnar select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 10677fbbc81SMark Salter select ARCH_MIGHT_HAVE_PC_PARPORT 1075e2c18c0SMark Salter select ARCH_MIGHT_HAVE_PC_SERIO 1083599fe12SThomas Gleixner select ARCH_STACKWALK 1092c870e61SArnd Bergmann select ARCH_SUPPORTS_ACPI 1106471b825SIngo Molnar select ARCH_SUPPORTS_ATOMIC_RMW 1115d6ad668SMike Rapoport select ARCH_SUPPORTS_DEBUG_PAGEALLOC 112d283d422SPasha Tatashin select ARCH_SUPPORTS_PAGE_TABLE_CHECK if X86_64 1136471b825SIngo Molnar select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 11414df3267SThomas Gleixner select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 1153c516f89SSami Tolvanen select ARCH_SUPPORTS_CFI_CLANG if X86_64 1163c516f89SSami Tolvanen select ARCH_USES_CFI_TRAPS if X86_64 && CFI_CLANG 117583bfd48SNathan Chancellor select ARCH_SUPPORTS_LTO_CLANG 118583bfd48SNathan Chancellor select ARCH_SUPPORTS_LTO_CLANG_THIN 1196471b825SIngo Molnar select ARCH_USE_BUILTIN_BSWAP 120dce44566SAnshuman Khandual select ARCH_USE_MEMTEST 1216471b825SIngo Molnar select ARCH_USE_QUEUED_RWLOCKS 1226471b825SIngo Molnar select ARCH_USE_QUEUED_SPINLOCKS 1232ce0d7f9SMark Brown select ARCH_USE_SYM_ANNOTATIONS 124ce4a4e56SAndy Lutomirski select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 12581c22041SDaniel Borkmann select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 126c763ea26SIngo Molnar select ARCH_WANTS_DYNAMIC_TASK_STRUCT 12751c2ee6dSNick Desaulniers select ARCH_WANTS_NO_INSTR 12807431506SAnshuman Khandual select ARCH_WANT_GENERAL_HUGETLB 1293876d4a3SAlexandre Ghiti select ARCH_WANT_HUGE_PMD_SHARE 13059612b24SNathan Chancellor select ARCH_WANT_LD_ORPHAN_WARN 131*0b6f1582SAneesh Kumar K.V select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP if X86_64 132*0b6f1582SAneesh Kumar K.V select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP if X86_64 13338d8b4e6SHuang Ying select ARCH_WANTS_THP_SWAP if X86_64 134b5f06f64SBalbir Singh select ARCH_HAS_PARANOID_L1D_FLUSH 13510916706SShile Zhang select BUILDTIME_TABLE_SORT 1366471b825SIngo Molnar select CLKEVT_I8253 1376471b825SIngo Molnar select CLOCKSOURCE_VALIDATE_LAST_CYCLE 1386471b825SIngo Molnar select CLOCKSOURCE_WATCHDOG 1397cf8f44aSAlexander Potapenko # Word-size accesses may read uninitialized data past the trailing \0 1407cf8f44aSAlexander Potapenko # in strings and cause false KMSAN reports. 1417cf8f44aSAlexander Potapenko select DCACHE_WORD_ACCESS if !KMSAN 1423aac3ebeSThomas Gleixner select DYNAMIC_SIGFRAME 14345471cd9SLinus Torvalds select EDAC_ATOMIC_SCRUB 14445471cd9SLinus Torvalds select EDAC_SUPPORT 1456471b825SIngo Molnar select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 1466471b825SIngo Molnar select GENERIC_CLOCKEVENTS_MIN_ADJUST 1476471b825SIngo Molnar select GENERIC_CMOS_UPDATE 1486471b825SIngo Molnar select GENERIC_CPU_AUTOPROBE 14961dc0f55SThomas Gleixner select GENERIC_CPU_VULNERABILITIES 1506471b825SIngo Molnar select GENERIC_EARLY_IOREMAP 15127d6b4d1SThomas Gleixner select GENERIC_ENTRY 1526471b825SIngo Molnar select GENERIC_IOMAP 153c7d6c9ddSThomas Gleixner select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 1540fa115daSThomas Gleixner select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 155ad7a929fSThomas Gleixner select GENERIC_IRQ_MIGRATION if SMP 1566471b825SIngo Molnar select GENERIC_IRQ_PROBE 157c201c917SThomas Gleixner select GENERIC_IRQ_RESERVATION_MODE 1586471b825SIngo Molnar select GENERIC_IRQ_SHOW 1596471b825SIngo Molnar select GENERIC_PENDING_IRQ if SMP 1602ae27137SSteven Price select GENERIC_PTDUMP 1616471b825SIngo Molnar select GENERIC_SMP_IDLE_THREAD 1626471b825SIngo Molnar select GENERIC_TIME_VSYSCALL 1637ac87074SVincenzo Frascino select GENERIC_GETTIMEOFDAY 164550a77a7SDmitry Safonov select GENERIC_VDSO_TIME_NS 1656ca297d4SPeter Zijlstra select GUP_GET_PXX_LOW_HIGH if X86_PAE 16617e5888eSHans de Goede select HARDIRQS_SW_RESEND 1677edaeb68SThomas Gleixner select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 168fcbfe812SNiklas Schnelle select HAS_IOPORT 1696471b825SIngo Molnar select HAVE_ACPI_APEI if ACPI 1706471b825SIngo Molnar select HAVE_ACPI_APEI_NMI if ACPI 1716471b825SIngo Molnar select HAVE_ALIGNED_STRUCT_PAGE if SLUB 1726471b825SIngo Molnar select HAVE_ARCH_AUDITSYSCALL 1736471b825SIngo Molnar select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 174eed1fceeSSong Liu select HAVE_ARCH_HUGE_VMALLOC if X86_64 1756471b825SIngo Molnar select HAVE_ARCH_JUMP_LABEL 176b34006c4SArd Biesheuvel select HAVE_ARCH_JUMP_LABEL_RELATIVE 177d17a1d97SAndrey Ryabinin select HAVE_ARCH_KASAN if X86_64 1780609ae01SDaniel Axtens select HAVE_ARCH_KASAN_VMALLOC if X86_64 1791dc0da6eSAlexander Potapenko select HAVE_ARCH_KFENCE 1804ca8cc8dSAlexander Potapenko select HAVE_ARCH_KMSAN if X86_64 1816471b825SIngo Molnar select HAVE_ARCH_KGDB 1829e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_BITS if MMU 1839e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 1841b028f78SDmitry Safonov select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 185271ca788SArd Biesheuvel select HAVE_ARCH_PREL32_RELOCATIONS 1866471b825SIngo Molnar select HAVE_ARCH_SECCOMP_FILTER 187f7d83c1cSKees Cook select HAVE_ARCH_THREAD_STRUCT_WHITELIST 188afaef01cSAlexander Popov select HAVE_ARCH_STACKLEAK 1896471b825SIngo Molnar select HAVE_ARCH_TRACEHOOK 1906471b825SIngo Molnar select HAVE_ARCH_TRANSPARENT_HUGEPAGE 191a00cc7d9SMatthew Wilcox select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 192b64d8d1eSPeter Xu select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 1937677f7fdSAxel Rasmussen select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 194e37e43a4SAndy Lutomirski select HAVE_ARCH_VMAP_STACK if X86_64 195fe950f60SKees Cook select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 196c763ea26SIngo Molnar select HAVE_ARCH_WITHIN_STACK_FRAMES 1972ff2b7ecSMasahiro Yamada select HAVE_ASM_MODVERSIONS 1986471b825SIngo Molnar select HAVE_CMPXCHG_DOUBLE 1996471b825SIngo Molnar select HAVE_CMPXCHG_LOCAL 20024a9c541SFrederic Weisbecker select HAVE_CONTEXT_TRACKING_USER if X86_64 20124a9c541SFrederic Weisbecker select HAVE_CONTEXT_TRACKING_USER_OFFSTACK if HAVE_CONTEXT_TRACKING_USER 2026471b825SIngo Molnar select HAVE_C_RECORDMCOUNT 20303f16cd0SJosh Poimboeuf select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL 204280981d6SSathvika Vasireddy select HAVE_OBJTOOL_NOP_MCOUNT if HAVE_OBJTOOL_MCOUNT 2054ed308c4SSteven Rostedt (Google) select HAVE_BUILDTIME_MCOUNT_SORT 2066471b825SIngo Molnar select HAVE_DEBUG_KMEMLEAK 2079c5a3621SAkinobu Mita select HAVE_DMA_CONTIGUOUS 208677aa9f7SSteven Rostedt select HAVE_DYNAMIC_FTRACE 20906aeaaeaSMasami Hiramatsu select HAVE_DYNAMIC_FTRACE_WITH_REGS 21002a474caSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 211562955feSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 212c316eb44SHeiko Carstens select HAVE_SAMPLE_FTRACE_DIRECT if X86_64 213503e4510SHeiko Carstens select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64 21403f5781bSWang YanQing select HAVE_EBPF_JIT 21558340a07SJohannes Berg select HAVE_EFFICIENT_UNALIGNED_ACCESS 2166630a8e5SChristoph Hellwig select HAVE_EISA 2175f56a5dfSJiri Slaby select HAVE_EXIT_THREAD 21867a929e0SChristoph Hellwig select HAVE_FAST_GUP 219644e0e8dSSteven Rostedt (VMware) select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 2206471b825SIngo Molnar select HAVE_FTRACE_MCOUNT_RECORD 221d938ba17SDonglin Peng select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER 2224a30e4c9SSteven Rostedt (VMware) select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) 2236471b825SIngo Molnar select HAVE_FUNCTION_TRACER 2246b90bd4bSEmese Revfy select HAVE_GCC_PLUGINS 2250067f129SK.Prasad select HAVE_HW_BREAKPOINT 2266471b825SIngo Molnar select HAVE_IOREMAP_PROT 227624db9eaSThomas Gleixner select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 2286471b825SIngo Molnar select HAVE_IRQ_TIME_ACCOUNTING 2294ab7674fSJosh Poimboeuf select HAVE_JUMP_LABEL_HACK if HAVE_OBJTOOL 2306471b825SIngo Molnar select HAVE_KERNEL_BZIP2 2316471b825SIngo Molnar select HAVE_KERNEL_GZIP 2326471b825SIngo Molnar select HAVE_KERNEL_LZ4 2336471b825SIngo Molnar select HAVE_KERNEL_LZMA 2346471b825SIngo Molnar select HAVE_KERNEL_LZO 2356471b825SIngo Molnar select HAVE_KERNEL_XZ 236fb46d057SNick Terrell select HAVE_KERNEL_ZSTD 2376471b825SIngo Molnar select HAVE_KPROBES 2386471b825SIngo Molnar select HAVE_KPROBES_ON_FTRACE 239540adea3SMasami Hiramatsu select HAVE_FUNCTION_ERROR_INJECTION 2406471b825SIngo Molnar select HAVE_KRETPROBES 241f3a112c0SMasami Hiramatsu select HAVE_RETHOOK 2426471b825SIngo Molnar select HAVE_KVM 2436471b825SIngo Molnar select HAVE_LIVEPATCH if X86_64 2440102752eSFrederic Weisbecker select HAVE_MIXED_BREAKPOINTS_REGS 245ee9f8fceSJosh Poimboeuf select HAVE_MOD_ARCH_SPECIFIC 2469f132f7eSJoel Fernandes (Google) select HAVE_MOVE_PMD 247be37c98dSKalesh Singh select HAVE_MOVE_PUD 24822102f45SJosh Poimboeuf select HAVE_NOINSTR_HACK if HAVE_OBJTOOL 24942a0bb3fSPetr Mladek select HAVE_NMI 250489e355bSJosh Poimboeuf select HAVE_NOINSTR_VALIDATION if HAVE_OBJTOOL 25103f16cd0SJosh Poimboeuf select HAVE_OBJTOOL if X86_64 2526471b825SIngo Molnar select HAVE_OPTPROBES 2536471b825SIngo Molnar select HAVE_PCSPKR_PLATFORM 2546471b825SIngo Molnar select HAVE_PERF_EVENTS 255c01d4323SFrederic Weisbecker select HAVE_PERF_EVENTS_NMI 25692e5aae4SNicholas Piggin select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 257eb01d42aSChristoph Hellwig select HAVE_PCI 258c5e63197SJiri Olsa select HAVE_PERF_REGS 259c5ebcedbSJiri Olsa select HAVE_PERF_USER_STACK_DUMP 260ff2e6d72SPeter Zijlstra select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 2611e9fdf21SPeter Zijlstra select MMU_GATHER_MERGE_VMAS 26200998085SThomas Gleixner select HAVE_POSIX_CPU_TIMERS_TASK_WORK 2636471b825SIngo Molnar select HAVE_REGS_AND_STACK_ACCESS_API 26403f16cd0SJosh Poimboeuf select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC || STACK_VALIDATION 2653c88ee19SMasami Hiramatsu select HAVE_FUNCTION_ARG_ACCESS_API 2667ecd19cfSKefeng Wang select HAVE_SETUP_PER_CPU_AREA 267cd1a41ceSThomas Gleixner select HAVE_SOFTIRQ_ON_OWN_STACK 268d148eac0SMasahiro Yamada select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 26903f16cd0SJosh Poimboeuf select HAVE_STACK_VALIDATION if HAVE_OBJTOOL 270e6d6c071SJosh Poimboeuf select HAVE_STATIC_CALL 27103f16cd0SJosh Poimboeuf select HAVE_STATIC_CALL_INLINE if HAVE_OBJTOOL 27299cf983cSMark Rutland select HAVE_PREEMPT_DYNAMIC_CALL 273d6761b8fSMathieu Desnoyers select HAVE_RSEQ 27409498135SMiguel Ojeda select HAVE_RUST if X86_64 2756471b825SIngo Molnar select HAVE_SYSCALL_TRACEPOINTS 2765f3da8c0SJosh Poimboeuf select HAVE_UACCESS_VALIDATION if HAVE_OBJTOOL 2776471b825SIngo Molnar select HAVE_UNSTABLE_SCHED_CLOCK 2787c68af6eSAvi Kivity select HAVE_USER_RETURN_NOTIFIER 2797ac87074SVincenzo Frascino select HAVE_GENERIC_VDSO 2800c7ffa32SThomas Gleixner select HOTPLUG_PARALLEL if SMP && X86_64 28105736e4aSThomas Gleixner select HOTPLUG_SMT if SMP 2820c7ffa32SThomas Gleixner select HOTPLUG_SPLIT_STARTUP if SMP && X86_32 283c0185808SThomas Gleixner select IRQ_FORCED_THREADING 284c2508ec5SLinus Torvalds select LOCK_MM_AND_FIND_VMA 2857ecd19cfSKefeng Wang select NEED_PER_CPU_EMBED_FIRST_CHUNK 2867ecd19cfSKefeng Wang select NEED_PER_CPU_PAGE_FIRST_CHUNK 28786596f0aSChristoph Hellwig select NEED_SG_DMA_LENGTH 2882eac9c2dSChristoph Hellwig select PCI_DOMAINS if PCI 289625210cfSSinan Kaya select PCI_LOCKLESS_CONFIG if PCI 2906471b825SIngo Molnar select PERF_EVENTS 2913195ef59SPrarit Bhargava select RTC_LIB 292d6faca40SArnd Bergmann select RTC_MC146818_LIB 2936471b825SIngo Molnar select SPARSE_IRQ 2946471b825SIngo Molnar select SYSCTL_EXCEPTION_TRACE 29515f4eae7SAndy Lutomirski select THREAD_INFO_IN_TASK 2964aae683fSMasahiro Yamada select TRACE_IRQFLAGS_SUPPORT 2974510bffbSMark Rutland select TRACE_IRQFLAGS_NMI_SUPPORT 2986471b825SIngo Molnar select USER_STACKTRACE_SUPPORT 2993b02a051SIngo Molnar select HAVE_ARCH_KCSAN if X86_64 3000c608dadSAubrey Li select PROC_PID_ARCH_STATUS if PROC_FS 30150468e43SJarkko Sakkinen select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX 302d49a0626SPeter Zijlstra select FUNCTION_ALIGNMENT_16B if X86_64 || X86_ALIGNMENT_16 303d49a0626SPeter Zijlstra select FUNCTION_ALIGNMENT_4B 3049e2b4be3SNayna Jain imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 305ceea991aSJiri Olsa select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 3067d8330a5SBalbir Singh 307ba7e4d13SIngo Molnarconfig INSTRUCTION_DECODER 3083120e25eSJan Beulich def_bool y 3093120e25eSJan Beulich depends on KPROBES || PERF_EVENTS || UPROBES 310ba7e4d13SIngo Molnar 31151b26adaSLinus Torvaldsconfig OUTPUT_FORMAT 31251b26adaSLinus Torvalds string 31351b26adaSLinus Torvalds default "elf32-i386" if X86_32 31451b26adaSLinus Torvalds default "elf64-x86-64" if X86_64 31551b26adaSLinus Torvalds 3168d5fffb9SSam Ravnborgconfig LOCKDEP_SUPPORT 3173c2362e6SHarvey Harrison def_bool y 3188d5fffb9SSam Ravnborg 3198d5fffb9SSam Ravnborgconfig STACKTRACE_SUPPORT 3203c2362e6SHarvey Harrison def_bool y 3218d5fffb9SSam Ravnborg 3228d5fffb9SSam Ravnborgconfig MMU 3233c2362e6SHarvey Harrison def_bool y 3248d5fffb9SSam Ravnborg 3259e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MIN 3269e08f57dSDaniel Cashman default 28 if 64BIT 3279e08f57dSDaniel Cashman default 8 3289e08f57dSDaniel Cashman 3299e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MAX 3309e08f57dSDaniel Cashman default 32 if 64BIT 3319e08f57dSDaniel Cashman default 16 3329e08f57dSDaniel Cashman 3339e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MIN 3349e08f57dSDaniel Cashman default 8 3359e08f57dSDaniel Cashman 3369e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MAX 3379e08f57dSDaniel Cashman default 16 3389e08f57dSDaniel Cashman 3398d5fffb9SSam Ravnborgconfig SBUS 3408d5fffb9SSam Ravnborg bool 3418d5fffb9SSam Ravnborg 3428d5fffb9SSam Ravnborgconfig GENERIC_ISA_DMA 3433120e25eSJan Beulich def_bool y 3443120e25eSJan Beulich depends on ISA_DMA_API 3458d5fffb9SSam Ravnborg 346d911c67eSAlexander Potapenkoconfig GENERIC_CSUM 347d911c67eSAlexander Potapenko bool 348d911c67eSAlexander Potapenko default y if KMSAN || KASAN 349d911c67eSAlexander Potapenko 3508d5fffb9SSam Ravnborgconfig GENERIC_BUG 3513c2362e6SHarvey Harrison def_bool y 3528d5fffb9SSam Ravnborg depends on BUG 353b93a531eSJan Beulich select GENERIC_BUG_RELATIVE_POINTERS if X86_64 354b93a531eSJan Beulich 355b93a531eSJan Beulichconfig GENERIC_BUG_RELATIVE_POINTERS 356b93a531eSJan Beulich bool 3578d5fffb9SSam Ravnborg 3588d5fffb9SSam Ravnborgconfig ARCH_MAY_HAVE_PC_FDC 3593120e25eSJan Beulich def_bool y 3603120e25eSJan Beulich depends on ISA_DMA_API 3618d5fffb9SSam Ravnborg 3621032c0baSSam Ravnborgconfig GENERIC_CALIBRATE_DELAY 3631032c0baSSam Ravnborg def_bool y 3641032c0baSSam Ravnborg 3659a0b8415Svenkatesh.pallipadi@intel.comconfig ARCH_HAS_CPU_RELAX 3669a0b8415Svenkatesh.pallipadi@intel.com def_bool y 3678d5fffb9SSam Ravnborg 368801e4062SJohannes Bergconfig ARCH_HIBERNATION_POSSIBLE 369801e4062SJohannes Berg def_bool y 370801e4062SJohannes Berg 371f4cb5700SJohannes Bergconfig ARCH_SUSPEND_POSSIBLE 372f4cb5700SJohannes Berg def_bool y 373f4cb5700SJohannes Berg 3748d5fffb9SSam Ravnborgconfig AUDIT_ARCH 375e0fd24a3SJan Beulich def_bool y if X86_64 3768d5fffb9SSam Ravnborg 377d6f2d75aSAndrey Ryabininconfig KASAN_SHADOW_OFFSET 378d6f2d75aSAndrey Ryabinin hex 379d6f2d75aSAndrey Ryabinin depends on KASAN 380d6f2d75aSAndrey Ryabinin default 0xdffffc0000000000 381d6f2d75aSAndrey Ryabinin 38269575d38SShane Wangconfig HAVE_INTEL_TXT 38369575d38SShane Wang def_bool y 3846ea30386SKees Cook depends on INTEL_IOMMU && ACPI 38569575d38SShane Wang 3866b0c3d44SSam Ravnborgconfig X86_32_SMP 3876b0c3d44SSam Ravnborg def_bool y 3886b0c3d44SSam Ravnborg depends on X86_32 && SMP 3896b0c3d44SSam Ravnborg 3906b0c3d44SSam Ravnborgconfig X86_64_SMP 3916b0c3d44SSam Ravnborg def_bool y 3926b0c3d44SSam Ravnborg depends on X86_64 && SMP 3936b0c3d44SSam Ravnborg 3942b144498SSrikar Dronamrajuconfig ARCH_SUPPORTS_UPROBES 3952b144498SSrikar Dronamraju def_bool y 3962b144498SSrikar Dronamraju 397d20642f0SRob Herringconfig FIX_EARLYCON_MEM 398d20642f0SRob Herring def_bool y 399d20642f0SRob Herring 40094d49eb3SKirill A. Shutemovconfig DYNAMIC_PHYSICAL_MASK 40194d49eb3SKirill A. Shutemov bool 40294d49eb3SKirill A. Shutemov 40398233368SKirill A. Shutemovconfig PGTABLE_LEVELS 40498233368SKirill A. Shutemov int 40577ef56e4SKirill A. Shutemov default 5 if X86_5LEVEL 40698233368SKirill A. Shutemov default 4 if X86_64 40798233368SKirill A. Shutemov default 3 if X86_PAE 40898233368SKirill A. Shutemov default 2 40998233368SKirill A. Shutemov 4102a61f474SMasahiro Yamadaconfig CC_HAS_SANE_STACKPROTECTOR 4112a61f474SMasahiro Yamada bool 4121b866781SNathan Chancellor default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT 4131b866781SNathan Chancellor default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) 4142a61f474SMasahiro Yamada help 4152a61f474SMasahiro Yamada We have to make sure stack protector is unconditionally disabled if 4163fb0fdb3SAndy Lutomirski the compiler produces broken code or if it does not let us control 4173fb0fdb3SAndy Lutomirski the segment on 32-bit kernels. 4182a61f474SMasahiro Yamada 419506f1d07SSam Ravnborgmenu "Processor type and features" 420506f1d07SSam Ravnborg 421506f1d07SSam Ravnborgconfig SMP 422506f1d07SSam Ravnborg bool "Symmetric multi-processing support" 423a7f7f624SMasahiro Yamada help 424506f1d07SSam Ravnborg This enables support for systems with more than one CPU. If you have 4254a474157SRobert Graffham a system with only one CPU, say N. If you have a system with more 4264a474157SRobert Graffham than one CPU, say Y. 427506f1d07SSam Ravnborg 4284a474157SRobert Graffham If you say N here, the kernel will run on uni- and multiprocessor 429506f1d07SSam Ravnborg machines, but will use only one CPU of a multiprocessor machine. If 430506f1d07SSam Ravnborg you say Y here, the kernel will run on many, but not all, 4314a474157SRobert Graffham uniprocessor machines. On a uniprocessor machine, the kernel 432506f1d07SSam Ravnborg will run faster if you say N here. 433506f1d07SSam Ravnborg 434506f1d07SSam Ravnborg Note that if you say Y here and choose architecture "586" or 435506f1d07SSam Ravnborg "Pentium" under "Processor family", the kernel will not work on 486 436506f1d07SSam Ravnborg architectures. Similarly, multiprocessor kernels for the "PPro" 437506f1d07SSam Ravnborg architecture may not work on all Pentium based boards. 438506f1d07SSam Ravnborg 439506f1d07SSam Ravnborg People using multiprocessor machines who say Y here should also say 440506f1d07SSam Ravnborg Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 441506f1d07SSam Ravnborg Management" code will be disabled if you say Y here. 442506f1d07SSam Ravnborg 443ff61f079SJonathan Corbet See also <file:Documentation/arch/x86/i386/IO-APIC.rst>, 4444f4cfa6cSMauro Carvalho Chehab <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 445506f1d07SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 446506f1d07SSam Ravnborg 447506f1d07SSam Ravnborg If you don't know what to do here, say N. 448506f1d07SSam Ravnborg 44906cd9a7dSYinghai Luconfig X86_X2APIC 45006cd9a7dSYinghai Lu bool "Support x2apic" 45119e3d60dSJan Kiszka depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 452a7f7f624SMasahiro Yamada help 45306cd9a7dSYinghai Lu This enables x2apic support on CPUs that have this feature. 45406cd9a7dSYinghai Lu 45506cd9a7dSYinghai Lu This allows 32-bit apic IDs (so it can support very large systems), 45606cd9a7dSYinghai Lu and accesses the local apic via MSRs not via mmio. 45706cd9a7dSYinghai Lu 458b8d1d163SDaniel Sneddon Some Intel systems circa 2022 and later are locked into x2APIC mode 459b8d1d163SDaniel Sneddon and can not fall back to the legacy APIC modes if SGX or TDX are 460e3998434SMateusz Jończyk enabled in the BIOS. They will boot with very reduced functionality 461e3998434SMateusz Jończyk without enabling this option. 462b8d1d163SDaniel Sneddon 46306cd9a7dSYinghai Lu If you don't know what to do here, say N. 46406cd9a7dSYinghai Lu 4656695c85bSYinghai Luconfig X86_MPPARSE 4664590d98fSAndy Shevchenko bool "Enable MPS table" if ACPI 4677a527688SJan Beulich default y 4685ab74722SIngo Molnar depends on X86_LOCAL_APIC 469a7f7f624SMasahiro Yamada help 4706695c85bSYinghai Lu For old smp systems that do not have proper acpi support. Newer systems 4716695c85bSYinghai Lu (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 4726695c85bSYinghai Lu 473ddd70cf9SJun Nakajimaconfig GOLDFISH 474ddd70cf9SJun Nakajima def_bool y 475ddd70cf9SJun Nakajima depends on X86_GOLDFISH 476ddd70cf9SJun Nakajima 477e6d42931SJohannes Weinerconfig X86_CPU_RESCTRL 478e6d42931SJohannes Weiner bool "x86 CPU resource control support" 4796fe07ce3SBabu Moger depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 48059fe5a77SThomas Gleixner select KERNFS 481e79f15a4SChen Yu select PROC_CPU_RESCTRL if PROC_FS 48278e99b4aSFenghua Yu help 483e6d42931SJohannes Weiner Enable x86 CPU resource control support. 4846fe07ce3SBabu Moger 4856fe07ce3SBabu Moger Provide support for the allocation and monitoring of system resources 4866fe07ce3SBabu Moger usage by the CPU. 4876fe07ce3SBabu Moger 4886fe07ce3SBabu Moger Intel calls this Intel Resource Director Technology 4896fe07ce3SBabu Moger (Intel(R) RDT). More information about RDT can be found in the 4906fe07ce3SBabu Moger Intel x86 Architecture Software Developer Manual. 4916fe07ce3SBabu Moger 4926fe07ce3SBabu Moger AMD calls this AMD Platform Quality of Service (AMD QoS). 4936fe07ce3SBabu Moger More information about AMD QoS can be found in the AMD64 Technology 4946fe07ce3SBabu Moger Platform Quality of Service Extensions manual. 49578e99b4aSFenghua Yu 49678e99b4aSFenghua Yu Say N if unsure. 49778e99b4aSFenghua Yu 4988425091fSRavikiran G Thirumalaiif X86_32 499a0d0bb4dSRandy Dunlapconfig X86_BIGSMP 500a0d0bb4dSRandy Dunlap bool "Support for big SMP systems with more than 8 CPUs" 501a0d0bb4dSRandy Dunlap depends on SMP 502a7f7f624SMasahiro Yamada help 503e133f6eaSRandy Dunlap This option is needed for the systems that have more than 8 CPUs. 504a0d0bb4dSRandy Dunlap 505c5c606d9SRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 506c5c606d9SRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 507c5c606d9SRavikiran G Thirumalai default y 508a7f7f624SMasahiro Yamada help 50906ac8346SIngo Molnar If you disable this option then the kernel will only support 51006ac8346SIngo Molnar standard PC platforms. (which covers the vast majority of 51106ac8346SIngo Molnar systems out there.) 51206ac8346SIngo Molnar 5138425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5148425091fSRavikiran G Thirumalai for the following (non-PC) 32 bit x86 platforms: 515cb7b8023SBen Hutchings Goldfish (Android emulator) 5168425091fSRavikiran G Thirumalai AMD Elan 5178425091fSRavikiran G Thirumalai RDC R-321x SoC 5188425091fSRavikiran G Thirumalai SGI 320/540 (Visual Workstation) 51983125a3aSAlessandro Rubini STA2X11-based (e.g. Northville) 5203f4110a4SThomas Gleixner Moorestown MID devices 52106ac8346SIngo Molnar 52206ac8346SIngo Molnar If you have one of these systems, or if you want to build a 52306ac8346SIngo Molnar generic distribution kernel, say Y here - otherwise say N. 524758cd94aSJuerg Haefligerendif # X86_32 52506ac8346SIngo Molnar 5268425091fSRavikiran G Thirumalaiif X86_64 5278425091fSRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 5288425091fSRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 5298425091fSRavikiran G Thirumalai default y 530a7f7f624SMasahiro Yamada help 5318425091fSRavikiran G Thirumalai If you disable this option then the kernel will only support 5328425091fSRavikiran G Thirumalai standard PC platforms. (which covers the vast majority of 5338425091fSRavikiran G Thirumalai systems out there.) 5348425091fSRavikiran G Thirumalai 5358425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5368425091fSRavikiran G Thirumalai for the following (non-PC) 64 bit x86 platforms: 53744b111b5SSteffen Persvold Numascale NumaChip 5388425091fSRavikiran G Thirumalai ScaleMP vSMP 5398425091fSRavikiran G Thirumalai SGI Ultraviolet 5408425091fSRavikiran G Thirumalai 5418425091fSRavikiran G Thirumalai If you have one of these systems, or if you want to build a 5428425091fSRavikiran G Thirumalai generic distribution kernel, say Y here - otherwise say N. 543758cd94aSJuerg Haefligerendif # X86_64 544c5c606d9SRavikiran G Thirumalai# This is an alphabetically sorted list of 64 bit extended platforms 545c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 54644b111b5SSteffen Persvoldconfig X86_NUMACHIP 54744b111b5SSteffen Persvold bool "Numascale NumaChip" 54844b111b5SSteffen Persvold depends on X86_64 54944b111b5SSteffen Persvold depends on X86_EXTENDED_PLATFORM 55044b111b5SSteffen Persvold depends on NUMA 55144b111b5SSteffen Persvold depends on SMP 55244b111b5SSteffen Persvold depends on X86_X2APIC 553f9726bfdSDaniel J Blueman depends on PCI_MMCONFIG 554a7f7f624SMasahiro Yamada help 55544b111b5SSteffen Persvold Adds support for Numascale NumaChip large-SMP systems. Needed to 55644b111b5SSteffen Persvold enable more than ~168 cores. 55744b111b5SSteffen Persvold If you don't have one of these, you should say N here. 55803b48632SNick Piggin 5596a48565eSIngo Molnarconfig X86_VSMP 560c5c606d9SRavikiran G Thirumalai bool "ScaleMP vSMP" 5616276a074SBorislav Petkov select HYPERVISOR_GUEST 5626a48565eSIngo Molnar select PARAVIRT 5636a48565eSIngo Molnar depends on X86_64 && PCI 564c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 565ead91d4bSShai Fultheim depends on SMP 566a7f7f624SMasahiro Yamada help 5676a48565eSIngo Molnar Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 5686a48565eSIngo Molnar supposed to run on these EM64T-based machines. Only choose this option 5696a48565eSIngo Molnar if you have one of these machines. 5706a48565eSIngo Molnar 571c5c606d9SRavikiran G Thirumalaiconfig X86_UV 572c5c606d9SRavikiran G Thirumalai bool "SGI Ultraviolet" 573c5c606d9SRavikiran G Thirumalai depends on X86_64 574c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 57554c28d29SJack Steiner depends on NUMA 5761ecb4ae5SAndrew Morton depends on EFI 577c2209ea5SIngo Molnar depends on KEXEC_CORE 5789d6c26e7SSuresh Siddha depends on X86_X2APIC 5791222e564SIngo Molnar depends on PCI 580a7f7f624SMasahiro Yamada help 581c5c606d9SRavikiran G Thirumalai This option is needed in order to support SGI Ultraviolet systems. 582c5c606d9SRavikiran G Thirumalai If you don't have one of these, you should say N here. 583c5c606d9SRavikiran G Thirumalai 584c5c606d9SRavikiran G Thirumalai# Following is an alphabetically sorted list of 32 bit extended platforms 585c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 586506f1d07SSam Ravnborg 587ddd70cf9SJun Nakajimaconfig X86_GOLDFISH 588ddd70cf9SJun Nakajima bool "Goldfish (Virtual Platform)" 589cb7b8023SBen Hutchings depends on X86_EXTENDED_PLATFORM 590a7f7f624SMasahiro Yamada help 591ddd70cf9SJun Nakajima Enable support for the Goldfish virtual platform used primarily 592ddd70cf9SJun Nakajima for Android development. Unless you are building for the Android 593ddd70cf9SJun Nakajima Goldfish emulator say N here. 594ddd70cf9SJun Nakajima 595c751e17bSThomas Gleixnerconfig X86_INTEL_CE 596c751e17bSThomas Gleixner bool "CE4100 TV platform" 597c751e17bSThomas Gleixner depends on PCI 598c751e17bSThomas Gleixner depends on PCI_GODIRECT 5996084a6e2SJiang Liu depends on X86_IO_APIC 600c751e17bSThomas Gleixner depends on X86_32 601c751e17bSThomas Gleixner depends on X86_EXTENDED_PLATFORM 60237bc9f50SDirk Brandewie select X86_REBOOTFIXUPS 603da6b737bSSebastian Andrzej Siewior select OF 604da6b737bSSebastian Andrzej Siewior select OF_EARLY_FLATTREE 605a7f7f624SMasahiro Yamada help 606c751e17bSThomas Gleixner Select for the Intel CE media processor (CE4100) SOC. 607c751e17bSThomas Gleixner This option compiles in support for the CE4100 SOC for settop 608c751e17bSThomas Gleixner boxes and media devices. 609c751e17bSThomas Gleixner 6104cb9b00fSDavid Cohenconfig X86_INTEL_MID 61143605ef1SAlan Cox bool "Intel MID platform support" 61243605ef1SAlan Cox depends on X86_EXTENDED_PLATFORM 613edc6bc78SDavid Cohen depends on X86_PLATFORM_DEVICES 6141ea7c673SAlan Cox depends on PCI 6153fda5bb4SAndy Shevchenko depends on X86_64 || (PCI_GOANY && X86_32) 6161ea7c673SAlan Cox depends on X86_IO_APIC 6174cb9b00fSDavid Cohen select I2C 6187c9c3a1eSAlan Cox select DW_APB_TIMER 61954b34aa0SMika Westerberg select INTEL_SCU_PCI 620a7f7f624SMasahiro Yamada help 6214cb9b00fSDavid Cohen Select to build a kernel capable of supporting Intel MID (Mobile 6224cb9b00fSDavid Cohen Internet Device) platform systems which do not have the PCI legacy 6234cb9b00fSDavid Cohen interfaces. If you are building for a PC class system say N here. 6241ea7c673SAlan Cox 6254cb9b00fSDavid Cohen Intel MID platforms are based on an Intel processor and chipset which 6264cb9b00fSDavid Cohen consume less power than most of the x86 derivatives. 62743605ef1SAlan Cox 6288bbc2a13SBryan O'Donoghueconfig X86_INTEL_QUARK 6298bbc2a13SBryan O'Donoghue bool "Intel Quark platform support" 6308bbc2a13SBryan O'Donoghue depends on X86_32 6318bbc2a13SBryan O'Donoghue depends on X86_EXTENDED_PLATFORM 6328bbc2a13SBryan O'Donoghue depends on X86_PLATFORM_DEVICES 6338bbc2a13SBryan O'Donoghue depends on X86_TSC 6348bbc2a13SBryan O'Donoghue depends on PCI 6358bbc2a13SBryan O'Donoghue depends on PCI_GOANY 6368bbc2a13SBryan O'Donoghue depends on X86_IO_APIC 6378bbc2a13SBryan O'Donoghue select IOSF_MBI 6388bbc2a13SBryan O'Donoghue select INTEL_IMR 6399ab6eb51SAndy Shevchenko select COMMON_CLK 640a7f7f624SMasahiro Yamada help 6418bbc2a13SBryan O'Donoghue Select to include support for Quark X1000 SoC. 6428bbc2a13SBryan O'Donoghue Say Y here if you have a Quark based system such as the Arduino 6438bbc2a13SBryan O'Donoghue compatible Intel Galileo. 6448bbc2a13SBryan O'Donoghue 6453d48aab1SMika Westerbergconfig X86_INTEL_LPSS 6463d48aab1SMika Westerberg bool "Intel Low Power Subsystem Support" 6475962dd22SSinan Kaya depends on X86 && ACPI && PCI 6483d48aab1SMika Westerberg select COMMON_CLK 6490f531431SMathias Nyman select PINCTRL 650eebb3e8dSAndy Shevchenko select IOSF_MBI 651a7f7f624SMasahiro Yamada help 6523d48aab1SMika Westerberg Select to build support for Intel Low Power Subsystem such as 6533d48aab1SMika Westerberg found on Intel Lynxpoint PCH. Selecting this option enables 6540f531431SMathias Nyman things like clock tree (common clock framework) and pincontrol 6550f531431SMathias Nyman which are needed by the LPSS peripheral drivers. 6563d48aab1SMika Westerberg 65792082a88SKen Xueconfig X86_AMD_PLATFORM_DEVICE 65892082a88SKen Xue bool "AMD ACPI2Platform devices support" 65992082a88SKen Xue depends on ACPI 66092082a88SKen Xue select COMMON_CLK 66192082a88SKen Xue select PINCTRL 662a7f7f624SMasahiro Yamada help 66392082a88SKen Xue Select to interpret AMD specific ACPI device to platform device 66492082a88SKen Xue such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 66592082a88SKen Xue I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 66692082a88SKen Xue implemented under PINCTRL subsystem. 66792082a88SKen Xue 668ced3ce76SDavid E. Boxconfig IOSF_MBI 669ced3ce76SDavid E. Box tristate "Intel SoC IOSF Sideband support for SoC platforms" 670ced3ce76SDavid E. Box depends on PCI 671a7f7f624SMasahiro Yamada help 672ced3ce76SDavid E. Box This option enables sideband register access support for Intel SoC 673ced3ce76SDavid E. Box platforms. On these platforms the IOSF sideband is used in lieu of 674ced3ce76SDavid E. Box MSR's for some register accesses, mostly but not limited to thermal 675ced3ce76SDavid E. Box and power. Drivers may query the availability of this device to 676ced3ce76SDavid E. Box determine if they need the sideband in order to work on these 677ced3ce76SDavid E. Box platforms. The sideband is available on the following SoC products. 678ced3ce76SDavid E. Box This list is not meant to be exclusive. 679ced3ce76SDavid E. Box - BayTrail 680ced3ce76SDavid E. Box - Braswell 681ced3ce76SDavid E. Box - Quark 682ced3ce76SDavid E. Box 683ced3ce76SDavid E. Box You should say Y if you are running a kernel on one of these SoC's. 684ced3ce76SDavid E. Box 685ed2226bdSDavid E. Boxconfig IOSF_MBI_DEBUG 686ed2226bdSDavid E. Box bool "Enable IOSF sideband access through debugfs" 687ed2226bdSDavid E. Box depends on IOSF_MBI && DEBUG_FS 688a7f7f624SMasahiro Yamada help 689ed2226bdSDavid E. Box Select this option to expose the IOSF sideband access registers (MCR, 690ed2226bdSDavid E. Box MDR, MCRX) through debugfs to write and read register information from 691ed2226bdSDavid E. Box different units on the SoC. This is most useful for obtaining device 692ed2226bdSDavid E. Box state information for debug and analysis. As this is a general access 693ed2226bdSDavid E. Box mechanism, users of this option would have specific knowledge of the 694ed2226bdSDavid E. Box device they want to access. 695ed2226bdSDavid E. Box 696ed2226bdSDavid E. Box If you don't require the option or are in doubt, say N. 697ed2226bdSDavid E. Box 698c5c606d9SRavikiran G Thirumalaiconfig X86_RDC321X 699c5c606d9SRavikiran G Thirumalai bool "RDC R-321x SoC" 700506f1d07SSam Ravnborg depends on X86_32 701c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 702c5c606d9SRavikiran G Thirumalai select M486 703c5c606d9SRavikiran G Thirumalai select X86_REBOOTFIXUPS 704a7f7f624SMasahiro Yamada help 705c5c606d9SRavikiran G Thirumalai This option is needed for RDC R-321x system-on-chip, also known 706c5c606d9SRavikiran G Thirumalai as R-8610-(G). 707c5c606d9SRavikiran G Thirumalai If you don't have one of these chips, you should say N here. 708c5c606d9SRavikiran G Thirumalai 709e0c7ae37SIngo Molnarconfig X86_32_NON_STANDARD 7109c398017SIngo Molnar bool "Support non-standard 32-bit SMP architectures" 7119c398017SIngo Molnar depends on X86_32 && SMP 712c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 713a7f7f624SMasahiro Yamada help 714b5660ba7SH. Peter Anvin This option compiles in the bigsmp and STA2X11 default 715b5660ba7SH. Peter Anvin subarchitectures. It is intended for a generic binary 716b5660ba7SH. Peter Anvin kernel. If you select them all, kernel will probe it one by 717b5660ba7SH. Peter Anvin one and will fallback to default. 718d49c4288SYinghai Lu 719c5c606d9SRavikiran G Thirumalai# Alphabetically sorted list of Non standard 32 bit platforms 720d49c4288SYinghai Lu 721d949f36fSLinus Torvaldsconfig X86_SUPPORTS_MEMORY_FAILURE 7226fc108a0SJan Beulich def_bool y 723d949f36fSLinus Torvalds # MCE code calls memory_failure(): 724d949f36fSLinus Torvalds depends on X86_MCE 725d949f36fSLinus Torvalds # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 726d949f36fSLinus Torvalds # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 727d949f36fSLinus Torvalds depends on X86_64 || !SPARSEMEM 728d949f36fSLinus Torvalds select ARCH_SUPPORTS_MEMORY_FAILURE 729d949f36fSLinus Torvalds 73083125a3aSAlessandro Rubiniconfig STA2X11 73183125a3aSAlessandro Rubini bool "STA2X11 Companion Chip Support" 73283125a3aSAlessandro Rubini depends on X86_32_NON_STANDARD && PCI 73383125a3aSAlessandro Rubini select SWIOTLB 73483125a3aSAlessandro Rubini select MFD_STA2X11 7350145071bSLinus Walleij select GPIOLIB 736a7f7f624SMasahiro Yamada help 73783125a3aSAlessandro Rubini This adds support for boards based on the STA2X11 IO-Hub, 73883125a3aSAlessandro Rubini a.k.a. "ConneXt". The chip is used in place of the standard 73983125a3aSAlessandro Rubini PC chipset, so all "standard" peripherals are missing. If this 74083125a3aSAlessandro Rubini option is selected the kernel will still be able to boot on 74183125a3aSAlessandro Rubini standard PC machines. 74283125a3aSAlessandro Rubini 74382148d1dSShérabconfig X86_32_IRIS 74482148d1dSShérab tristate "Eurobraille/Iris poweroff module" 74582148d1dSShérab depends on X86_32 746a7f7f624SMasahiro Yamada help 74782148d1dSShérab The Iris machines from EuroBraille do not have APM or ACPI support 74882148d1dSShérab to shut themselves down properly. A special I/O sequence is 74982148d1dSShérab needed to do so, which is what this module does at 75082148d1dSShérab kernel shutdown. 75182148d1dSShérab 75282148d1dSShérab This is only for Iris machines from EuroBraille. 75382148d1dSShérab 75482148d1dSShérab If unused, say N. 75582148d1dSShérab 756ae1e9130SIngo Molnarconfig SCHED_OMIT_FRAME_POINTER 7573c2362e6SHarvey Harrison def_bool y 7583c2362e6SHarvey Harrison prompt "Single-depth WCHAN output" 759a87d0914SKen Chen depends on X86 760a7f7f624SMasahiro Yamada help 761506f1d07SSam Ravnborg Calculate simpler /proc/<PID>/wchan values. If this option 762506f1d07SSam Ravnborg is disabled then wchan values will recurse back to the 763506f1d07SSam Ravnborg caller function. This provides more accurate wchan values, 764506f1d07SSam Ravnborg at the expense of slightly more scheduling overhead. 765506f1d07SSam Ravnborg 766506f1d07SSam Ravnborg If in doubt, say "Y". 767506f1d07SSam Ravnborg 7686276a074SBorislav Petkovmenuconfig HYPERVISOR_GUEST 7696276a074SBorislav Petkov bool "Linux guest support" 770a7f7f624SMasahiro Yamada help 7716276a074SBorislav Petkov Say Y here to enable options for running Linux under various hyper- 7726276a074SBorislav Petkov visors. This option enables basic hypervisor detection and platform 7736276a074SBorislav Petkov setup. 774506f1d07SSam Ravnborg 7756276a074SBorislav Petkov If you say N, all options in this submenu will be skipped and 7766276a074SBorislav Petkov disabled, and Linux guest support won't be built in. 777506f1d07SSam Ravnborg 7786276a074SBorislav Petkovif HYPERVISOR_GUEST 779506f1d07SSam Ravnborg 780e61bd94aSEduardo Pereira Habkostconfig PARAVIRT 781e61bd94aSEduardo Pereira Habkost bool "Enable paravirtualization code" 782a0e2bf7cSJuergen Gross depends on HAVE_STATIC_CALL 783a7f7f624SMasahiro Yamada help 784e61bd94aSEduardo Pereira Habkost This changes the kernel so it can modify itself when it is run 785e61bd94aSEduardo Pereira Habkost under a hypervisor, potentially improving performance significantly 786e61bd94aSEduardo Pereira Habkost over full virtualization. However, when run without a hypervisor 787e61bd94aSEduardo Pereira Habkost the kernel is theoretically slower and slightly larger. 788e61bd94aSEduardo Pereira Habkost 789c00a280aSJuergen Grossconfig PARAVIRT_XXL 790c00a280aSJuergen Gross bool 791c00a280aSJuergen Gross 7926276a074SBorislav Petkovconfig PARAVIRT_DEBUG 7936276a074SBorislav Petkov bool "paravirt-ops debugging" 7946276a074SBorislav Petkov depends on PARAVIRT && DEBUG_KERNEL 795a7f7f624SMasahiro Yamada help 7966276a074SBorislav Petkov Enable to debug paravirt_ops internals. Specifically, BUG if 7976276a074SBorislav Petkov a paravirt_op is missing when it is called. 7986276a074SBorislav Petkov 799b4ecc126SJeremy Fitzhardingeconfig PARAVIRT_SPINLOCKS 800b4ecc126SJeremy Fitzhardinge bool "Paravirtualization layer for spinlocks" 8016ea30386SKees Cook depends on PARAVIRT && SMP 802a7f7f624SMasahiro Yamada help 803b4ecc126SJeremy Fitzhardinge Paravirtualized spinlocks allow a pvops backend to replace the 804b4ecc126SJeremy Fitzhardinge spinlock implementation with something virtualization-friendly 805b4ecc126SJeremy Fitzhardinge (for example, block the virtual CPU rather than spinning). 806b4ecc126SJeremy Fitzhardinge 8074c4e4f61SRaghavendra K T It has a minimal impact on native kernels and gives a nice performance 8084c4e4f61SRaghavendra K T benefit on paravirtualized KVM / Xen kernels. 809b4ecc126SJeremy Fitzhardinge 8104c4e4f61SRaghavendra K T If you are unsure how to answer this question, answer Y. 811b4ecc126SJeremy Fitzhardinge 812ecca2502SZhao Yakuiconfig X86_HV_CALLBACK_VECTOR 813ecca2502SZhao Yakui def_bool n 814ecca2502SZhao Yakui 8156276a074SBorislav Petkovsource "arch/x86/xen/Kconfig" 8166276a074SBorislav Petkov 8176276a074SBorislav Petkovconfig KVM_GUEST 8186276a074SBorislav Petkov bool "KVM Guest support (including kvmclock)" 8196276a074SBorislav Petkov depends on PARAVIRT 8206276a074SBorislav Petkov select PARAVIRT_CLOCK 821a1c4423bSMarcelo Tosatti select ARCH_CPUIDLE_HALTPOLL 822b1d40575SVitaly Kuznetsov select X86_HV_CALLBACK_VECTOR 8236276a074SBorislav Petkov default y 824a7f7f624SMasahiro Yamada help 8256276a074SBorislav Petkov This option enables various optimizations for running under the KVM 8266276a074SBorislav Petkov hypervisor. It includes a paravirtualized clock, so that instead 8276276a074SBorislav Petkov of relying on a PIT (or probably other) emulation by the 8286276a074SBorislav Petkov underlying device model, the host provides the guest with 8296276a074SBorislav Petkov timing infrastructure such as time of day, and system time 8306276a074SBorislav Petkov 831a1c4423bSMarcelo Tosatticonfig ARCH_CPUIDLE_HALTPOLL 832a1c4423bSMarcelo Tosatti def_bool n 833a1c4423bSMarcelo Tosatti prompt "Disable host haltpoll when loading haltpoll driver" 834a1c4423bSMarcelo Tosatti help 835a1c4423bSMarcelo Tosatti If virtualized under KVM, disable host haltpoll. 836a1c4423bSMarcelo Tosatti 8377733607fSMaran Wilsonconfig PVH 8387733607fSMaran Wilson bool "Support for running PVH guests" 839a7f7f624SMasahiro Yamada help 8407733607fSMaran Wilson This option enables the PVH entry point for guest virtual machines 8417733607fSMaran Wilson as specified in the x86/HVM direct boot ABI. 8427733607fSMaran Wilson 8436276a074SBorislav Petkovconfig PARAVIRT_TIME_ACCOUNTING 8446276a074SBorislav Petkov bool "Paravirtual steal time accounting" 8456276a074SBorislav Petkov depends on PARAVIRT 846a7f7f624SMasahiro Yamada help 8476276a074SBorislav Petkov Select this option to enable fine granularity task steal time 8486276a074SBorislav Petkov accounting. Time spent executing other tasks in parallel with 8496276a074SBorislav Petkov the current vCPU is discounted from the vCPU power. To account for 8506276a074SBorislav Petkov that, there can be a small performance impact. 8516276a074SBorislav Petkov 8526276a074SBorislav Petkov If in doubt, say N here. 8536276a074SBorislav Petkov 8547af192c9SGerd Hoffmannconfig PARAVIRT_CLOCK 8557af192c9SGerd Hoffmann bool 8567af192c9SGerd Hoffmann 8574a362601SJan Kiszkaconfig JAILHOUSE_GUEST 8584a362601SJan Kiszka bool "Jailhouse non-root cell support" 859abde587bSArnd Bergmann depends on X86_64 && PCI 86087e65d05SJan Kiszka select X86_PM_TIMER 861a7f7f624SMasahiro Yamada help 8624a362601SJan Kiszka This option allows to run Linux as guest in a Jailhouse non-root 8634a362601SJan Kiszka cell. You can leave this option disabled if you only want to start 8644a362601SJan Kiszka Jailhouse and run Linux afterwards in the root cell. 8654a362601SJan Kiszka 866ec7972c9SZhao Yakuiconfig ACRN_GUEST 867ec7972c9SZhao Yakui bool "ACRN Guest support" 868ec7972c9SZhao Yakui depends on X86_64 869498ad393SZhao Yakui select X86_HV_CALLBACK_VECTOR 870ec7972c9SZhao Yakui help 871ec7972c9SZhao Yakui This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 872ec7972c9SZhao Yakui a flexible, lightweight reference open-source hypervisor, built with 873ec7972c9SZhao Yakui real-time and safety-criticality in mind. It is built for embedded 874ec7972c9SZhao Yakui IOT with small footprint and real-time features. More details can be 875ec7972c9SZhao Yakui found in https://projectacrn.org/. 876ec7972c9SZhao Yakui 87759bd54a8SKuppuswamy Sathyanarayananconfig INTEL_TDX_GUEST 87859bd54a8SKuppuswamy Sathyanarayanan bool "Intel TDX (Trust Domain Extensions) - Guest Support" 87959bd54a8SKuppuswamy Sathyanarayanan depends on X86_64 && CPU_SUP_INTEL 88059bd54a8SKuppuswamy Sathyanarayanan depends on X86_X2APIC 88175d090fdSKirill A. Shutemov depends on EFI_STUB 88241394e33SKirill A. Shutemov select ARCH_HAS_CC_PLATFORM 883968b4931SKirill A. Shutemov select X86_MEM_ENCRYPT 88477a512e3SSean Christopherson select X86_MCE 88575d090fdSKirill A. Shutemov select UNACCEPTED_MEMORY 88659bd54a8SKuppuswamy Sathyanarayanan help 88759bd54a8SKuppuswamy Sathyanarayanan Support running as a guest under Intel TDX. Without this support, 88859bd54a8SKuppuswamy Sathyanarayanan the guest kernel can not boot or run under TDX. 88959bd54a8SKuppuswamy Sathyanarayanan TDX includes memory encryption and integrity capabilities 89059bd54a8SKuppuswamy Sathyanarayanan which protect the confidentiality and integrity of guest 89159bd54a8SKuppuswamy Sathyanarayanan memory contents and CPU state. TDX guests are protected from 89259bd54a8SKuppuswamy Sathyanarayanan some attacks from the VMM. 89359bd54a8SKuppuswamy Sathyanarayanan 8946276a074SBorislav Petkovendif # HYPERVISOR_GUEST 89597349135SJeremy Fitzhardinge 896506f1d07SSam Ravnborgsource "arch/x86/Kconfig.cpu" 897506f1d07SSam Ravnborg 898506f1d07SSam Ravnborgconfig HPET_TIMER 8993c2362e6SHarvey Harrison def_bool X86_64 900506f1d07SSam Ravnborg prompt "HPET Timer Support" if X86_32 901a7f7f624SMasahiro Yamada help 902506f1d07SSam Ravnborg Use the IA-PC HPET (High Precision Event Timer) to manage 903506f1d07SSam Ravnborg time in preference to the PIT and RTC, if a HPET is 904506f1d07SSam Ravnborg present. 905506f1d07SSam Ravnborg HPET is the next generation timer replacing legacy 8254s. 906506f1d07SSam Ravnborg The HPET provides a stable time base on SMP 907506f1d07SSam Ravnborg systems, unlike the TSC, but it is more expensive to access, 9084e7f9df2SMichael S. Tsirkin as it is off-chip. The interface used is documented 9094e7f9df2SMichael S. Tsirkin in the HPET spec, revision 1. 910506f1d07SSam Ravnborg 911506f1d07SSam Ravnborg You can safely choose Y here. However, HPET will only be 912506f1d07SSam Ravnborg activated if the platform and the BIOS support this feature. 913506f1d07SSam Ravnborg Otherwise the 8254 will be used for timing services. 914506f1d07SSam Ravnborg 915506f1d07SSam Ravnborg Choose N to continue using the legacy 8254 timer. 916506f1d07SSam Ravnborg 917506f1d07SSam Ravnborgconfig HPET_EMULATE_RTC 9183c2362e6SHarvey Harrison def_bool y 9193228e1dcSAnand K Mistry depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 920506f1d07SSam Ravnborg 9216a108a14SDavid Rientjes# Mark as expert because too many people got it wrong. 922506f1d07SSam Ravnborg# The code disables itself when not needed. 9237ae9392cSThomas Petazzoniconfig DMI 9247ae9392cSThomas Petazzoni default y 925cf074402SArd Biesheuvel select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 9266a108a14SDavid Rientjes bool "Enable DMI scanning" if EXPERT 927a7f7f624SMasahiro Yamada help 9287ae9392cSThomas Petazzoni Enabled scanning of DMI to identify machine quirks. Say Y 9297ae9392cSThomas Petazzoni here unless you have verified that your setup is not 9307ae9392cSThomas Petazzoni affected by entries in the DMI blacklist. Required by PNP 9317ae9392cSThomas Petazzoni BIOS code. 9327ae9392cSThomas Petazzoni 933506f1d07SSam Ravnborgconfig GART_IOMMU 93438901f1cSAndi Kleen bool "Old AMD GART IOMMU support" 9352f9237d4SChristoph Hellwig select DMA_OPS 936a4ce5a48SChristoph Hellwig select IOMMU_HELPER 937506f1d07SSam Ravnborg select SWIOTLB 93823ac4ae8SAndreas Herrmann depends on X86_64 && PCI && AMD_NB 939a7f7f624SMasahiro Yamada help 940ced3c42cSIngo Molnar Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 941ced3c42cSIngo Molnar GART based hardware IOMMUs. 942ced3c42cSIngo Molnar 943ced3c42cSIngo Molnar The GART supports full DMA access for devices with 32-bit access 944ced3c42cSIngo Molnar limitations, on systems with more than 3 GB. This is usually needed 945ced3c42cSIngo Molnar for USB, sound, many IDE/SATA chipsets and some other devices. 946ced3c42cSIngo Molnar 947ced3c42cSIngo Molnar Newer systems typically have a modern AMD IOMMU, supported via 948ced3c42cSIngo Molnar the CONFIG_AMD_IOMMU=y config option. 949ced3c42cSIngo Molnar 950ced3c42cSIngo Molnar In normal configurations this driver is only active when needed: 951ced3c42cSIngo Molnar there's more than 3 GB of memory and the system contains a 952ced3c42cSIngo Molnar 32-bit limited device. 953ced3c42cSIngo Molnar 954ced3c42cSIngo Molnar If unsure, say Y. 955506f1d07SSam Ravnborg 9568b766b0fSMichal Suchanekconfig BOOT_VESA_SUPPORT 9578b766b0fSMichal Suchanek bool 9588b766b0fSMichal Suchanek help 9598b766b0fSMichal Suchanek If true, at least one selected framebuffer driver can take advantage 9608b766b0fSMichal Suchanek of VESA video modes set at an early boot stage via the vga= parameter. 9618b766b0fSMichal Suchanek 9621184dc2fSMike Travisconfig MAXSMP 963ddb0c5a6SSamuel Thibault bool "Enable Maximum number of SMP Processors and NUMA Nodes" 9646ea30386SKees Cook depends on X86_64 && SMP && DEBUG_KERNEL 96536f5101aSMike Travis select CPUMASK_OFFSTACK 966a7f7f624SMasahiro Yamada help 967ddb0c5a6SSamuel Thibault Enable maximum number of CPUS and NUMA Nodes for this architecture. 9681184dc2fSMike Travis If unsure, say N. 969506f1d07SSam Ravnborg 970aec6487eSIngo Molnar# 971aec6487eSIngo Molnar# The maximum number of CPUs supported: 972aec6487eSIngo Molnar# 973aec6487eSIngo Molnar# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 974aec6487eSIngo Molnar# and which can be configured interactively in the 975aec6487eSIngo Molnar# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 976aec6487eSIngo Molnar# 977aec6487eSIngo Molnar# The ranges are different on 32-bit and 64-bit kernels, depending on 978aec6487eSIngo Molnar# hardware capabilities and scalability features of the kernel. 979aec6487eSIngo Molnar# 980aec6487eSIngo Molnar# ( If MAXSMP is enabled we just use the highest possible value and disable 981aec6487eSIngo Molnar# interactive configuration. ) 982aec6487eSIngo Molnar# 983a0d0bb4dSRandy Dunlap 984aec6487eSIngo Molnarconfig NR_CPUS_RANGE_BEGIN 985a0d0bb4dSRandy Dunlap int 986aec6487eSIngo Molnar default NR_CPUS_RANGE_END if MAXSMP 987a0d0bb4dSRandy Dunlap default 1 if !SMP 988a0d0bb4dSRandy Dunlap default 2 989a0d0bb4dSRandy Dunlap 990aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 991a0d0bb4dSRandy Dunlap int 992a0d0bb4dSRandy Dunlap depends on X86_32 993aec6487eSIngo Molnar default 64 if SMP && X86_BIGSMP 994aec6487eSIngo Molnar default 8 if SMP && !X86_BIGSMP 995a0d0bb4dSRandy Dunlap default 1 if !SMP 996a0d0bb4dSRandy Dunlap 997aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 998a0d0bb4dSRandy Dunlap int 999a0d0bb4dSRandy Dunlap depends on X86_64 10001edae1aeSScott Wood default 8192 if SMP && CPUMASK_OFFSTACK 10011edae1aeSScott Wood default 512 if SMP && !CPUMASK_OFFSTACK 1002a0d0bb4dSRandy Dunlap default 1 if !SMP 1003aec6487eSIngo Molnar 1004aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 1005aec6487eSIngo Molnar int 1006aec6487eSIngo Molnar depends on X86_32 1007aec6487eSIngo Molnar default 32 if X86_BIGSMP 1008aec6487eSIngo Molnar default 8 if SMP 1009aec6487eSIngo Molnar default 1 if !SMP 1010aec6487eSIngo Molnar 1011aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 1012aec6487eSIngo Molnar int 1013aec6487eSIngo Molnar depends on X86_64 1014a0d0bb4dSRandy Dunlap default 8192 if MAXSMP 1015a0d0bb4dSRandy Dunlap default 64 if SMP 1016aec6487eSIngo Molnar default 1 if !SMP 1017a0d0bb4dSRandy Dunlap 1018506f1d07SSam Ravnborgconfig NR_CPUS 101936f5101aSMike Travis int "Maximum number of CPUs" if SMP && !MAXSMP 1020aec6487eSIngo Molnar range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1021aec6487eSIngo Molnar default NR_CPUS_DEFAULT 1022a7f7f624SMasahiro Yamada help 1023506f1d07SSam Ravnborg This allows you to specify the maximum number of CPUs which this 1024bb61ccc7SJosh Boyer kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1025cad14bb9SKirill A. Shutemov supported value is 8192, otherwise the maximum value is 512. The 1026506f1d07SSam Ravnborg minimum value which makes sense is 2. 1027506f1d07SSam Ravnborg 1028aec6487eSIngo Molnar This is purely to save memory: each supported CPU adds about 8KB 1029aec6487eSIngo Molnar to the kernel image. 1030506f1d07SSam Ravnborg 103166558b73STim Chenconfig SCHED_CLUSTER 103266558b73STim Chen bool "Cluster scheduler support" 103366558b73STim Chen depends on SMP 103466558b73STim Chen default y 103566558b73STim Chen help 103666558b73STim Chen Cluster scheduler support improves the CPU scheduler's decision 103766558b73STim Chen making when dealing with machines that have clusters of CPUs. 103866558b73STim Chen Cluster usually means a couple of CPUs which are placed closely 103966558b73STim Chen by sharing mid-level caches, last-level cache tags or internal 104066558b73STim Chen busses. 104166558b73STim Chen 1042506f1d07SSam Ravnborgconfig SCHED_SMT 1043dbe73364SThomas Gleixner def_bool y if SMP 1044506f1d07SSam Ravnborg 1045506f1d07SSam Ravnborgconfig SCHED_MC 10463c2362e6SHarvey Harrison def_bool y 10473c2362e6SHarvey Harrison prompt "Multi-core scheduler support" 1048c8e56d20SBorislav Petkov depends on SMP 1049a7f7f624SMasahiro Yamada help 1050506f1d07SSam Ravnborg Multi-core scheduler support improves the CPU scheduler's decision 1051506f1d07SSam Ravnborg making when dealing with multi-core CPU chips at a cost of slightly 1052506f1d07SSam Ravnborg increased overhead in some places. If unsure say N here. 1053506f1d07SSam Ravnborg 1054de966cf4STim Chenconfig SCHED_MC_PRIO 1055de966cf4STim Chen bool "CPU core priorities scheduler support" 10560a21fc12SIngo Molnar depends on SCHED_MC && CPU_SUP_INTEL 10570a21fc12SIngo Molnar select X86_INTEL_PSTATE 10580a21fc12SIngo Molnar select CPU_FREQ 1059de966cf4STim Chen default y 1060a7f7f624SMasahiro Yamada help 1061de966cf4STim Chen Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1062de966cf4STim Chen core ordering determined at manufacturing time, which allows 1063de966cf4STim Chen certain cores to reach higher turbo frequencies (when running 1064de966cf4STim Chen single threaded workloads) than others. 1065de966cf4STim Chen 1066de966cf4STim Chen Enabling this kernel feature teaches the scheduler about 1067de966cf4STim Chen the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1068de966cf4STim Chen scheduler's CPU selection logic accordingly, so that higher 1069de966cf4STim Chen overall system performance can be achieved. 1070de966cf4STim Chen 1071de966cf4STim Chen This feature will have no effect on CPUs without this feature. 1072de966cf4STim Chen 1073de966cf4STim Chen If unsure say Y here. 10745e76b2abSTim Chen 107530b8b006SThomas Gleixnerconfig UP_LATE_INIT 107630b8b006SThomas Gleixner def_bool y 1077ba360f88SThomas Gleixner depends on !SMP && X86_LOCAL_APIC 107830b8b006SThomas Gleixner 1079506f1d07SSam Ravnborgconfig X86_UP_APIC 108050849eefSJan Beulich bool "Local APIC support on uniprocessors" if !PCI_MSI 108150849eefSJan Beulich default PCI_MSI 108238a1dfdaSBryan O'Donoghue depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1083a7f7f624SMasahiro Yamada help 1084506f1d07SSam Ravnborg A local APIC (Advanced Programmable Interrupt Controller) is an 1085506f1d07SSam Ravnborg integrated interrupt controller in the CPU. If you have a single-CPU 1086506f1d07SSam Ravnborg system which has a processor with a local APIC, you can say Y here to 1087506f1d07SSam Ravnborg enable and use it. If you say Y here even though your machine doesn't 1088506f1d07SSam Ravnborg have a local APIC, then the kernel will still run with no slowdown at 1089506f1d07SSam Ravnborg all. The local APIC supports CPU-generated self-interrupts (timer, 1090506f1d07SSam Ravnborg performance counters), and the NMI watchdog which detects hard 1091506f1d07SSam Ravnborg lockups. 1092506f1d07SSam Ravnborg 1093506f1d07SSam Ravnborgconfig X86_UP_IOAPIC 1094506f1d07SSam Ravnborg bool "IO-APIC support on uniprocessors" 1095506f1d07SSam Ravnborg depends on X86_UP_APIC 1096a7f7f624SMasahiro Yamada help 1097506f1d07SSam Ravnborg An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1098506f1d07SSam Ravnborg SMP-capable replacement for PC-style interrupt controllers. Most 1099506f1d07SSam Ravnborg SMP systems and many recent uniprocessor systems have one. 1100506f1d07SSam Ravnborg 1101506f1d07SSam Ravnborg If you have a single-CPU system with an IO-APIC, you can say Y here 1102506f1d07SSam Ravnborg to use it. If you say Y here even though your machine doesn't have 1103506f1d07SSam Ravnborg an IO-APIC, then the kernel will still run with no slowdown at all. 1104506f1d07SSam Ravnborg 1105506f1d07SSam Ravnborgconfig X86_LOCAL_APIC 11063c2362e6SHarvey Harrison def_bool y 11070dbc6078SThomas Petazzoni depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1108b5dc8e6cSJiang Liu select IRQ_DOMAIN_HIERARCHY 1109506f1d07SSam Ravnborg 1110506f1d07SSam Ravnborgconfig X86_IO_APIC 1111b1da1e71SJan Beulich def_bool y 1112b1da1e71SJan Beulich depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1113506f1d07SSam Ravnborg 111441b9eb26SStefan Assmannconfig X86_REROUTE_FOR_BROKEN_BOOT_IRQS 111541b9eb26SStefan Assmann bool "Reroute for broken boot IRQs" 111641b9eb26SStefan Assmann depends on X86_IO_APIC 1117a7f7f624SMasahiro Yamada help 111841b9eb26SStefan Assmann This option enables a workaround that fixes a source of 111941b9eb26SStefan Assmann spurious interrupts. This is recommended when threaded 112041b9eb26SStefan Assmann interrupt handling is used on systems where the generation of 112141b9eb26SStefan Assmann superfluous "boot interrupts" cannot be disabled. 112241b9eb26SStefan Assmann 112341b9eb26SStefan Assmann Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 112441b9eb26SStefan Assmann entry in the chipset's IO-APIC is masked (as, e.g. the RT 112541b9eb26SStefan Assmann kernel does during interrupt handling). On chipsets where this 112641b9eb26SStefan Assmann boot IRQ generation cannot be disabled, this workaround keeps 112741b9eb26SStefan Assmann the original IRQ line masked so that only the equivalent "boot 112841b9eb26SStefan Assmann IRQ" is delivered to the CPUs. The workaround also tells the 112941b9eb26SStefan Assmann kernel to set up the IRQ handler on the boot IRQ line. In this 113041b9eb26SStefan Assmann way only one interrupt is delivered to the kernel. Otherwise 113141b9eb26SStefan Assmann the spurious second interrupt may cause the kernel to bring 113241b9eb26SStefan Assmann down (vital) interrupt lines. 113341b9eb26SStefan Assmann 113441b9eb26SStefan Assmann Only affects "broken" chipsets. Interrupt sharing may be 113541b9eb26SStefan Assmann increased on these systems. 113641b9eb26SStefan Assmann 1137506f1d07SSam Ravnborgconfig X86_MCE 1138bab9bc65SAndi Kleen bool "Machine Check / overheating reporting" 1139648ed940SChen, Gong select GENERIC_ALLOCATOR 1140e57dbaf7SBorislav Petkov default y 1141a7f7f624SMasahiro Yamada help 1142bab9bc65SAndi Kleen Machine Check support allows the processor to notify the 1143bab9bc65SAndi Kleen kernel if it detects a problem (e.g. overheating, data corruption). 1144506f1d07SSam Ravnborg The action the kernel takes depends on the severity of the problem, 1145bab9bc65SAndi Kleen ranging from warning messages to halting the machine. 11464efc0670SAndi Kleen 11475de97c9fSTony Luckconfig X86_MCELOG_LEGACY 11485de97c9fSTony Luck bool "Support for deprecated /dev/mcelog character device" 11495de97c9fSTony Luck depends on X86_MCE 1150a7f7f624SMasahiro Yamada help 11515de97c9fSTony Luck Enable support for /dev/mcelog which is needed by the old mcelog 11525de97c9fSTony Luck userspace logging daemon. Consider switching to the new generation 11535de97c9fSTony Luck rasdaemon solution. 11545de97c9fSTony Luck 1155506f1d07SSam Ravnborgconfig X86_MCE_INTEL 11563c2362e6SHarvey Harrison def_bool y 11573c2362e6SHarvey Harrison prompt "Intel MCE features" 1158c1ebf835SAndi Kleen depends on X86_MCE && X86_LOCAL_APIC 1159a7f7f624SMasahiro Yamada help 1160506f1d07SSam Ravnborg Additional support for intel specific MCE features such as 1161506f1d07SSam Ravnborg the thermal monitor. 1162506f1d07SSam Ravnborg 1163506f1d07SSam Ravnborgconfig X86_MCE_AMD 11643c2362e6SHarvey Harrison def_bool y 11653c2362e6SHarvey Harrison prompt "AMD MCE features" 1166f5382de9SYazen Ghannam depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1167a7f7f624SMasahiro Yamada help 1168506f1d07SSam Ravnborg Additional support for AMD specific MCE features such as 1169506f1d07SSam Ravnborg the DRAM Error Threshold. 1170506f1d07SSam Ravnborg 11714efc0670SAndi Kleenconfig X86_ANCIENT_MCE 11726fc108a0SJan Beulich bool "Support for old Pentium 5 / WinChip machine checks" 1173c31d9633SAndi Kleen depends on X86_32 && X86_MCE 1174a7f7f624SMasahiro Yamada help 11754efc0670SAndi Kleen Include support for machine check handling on old Pentium 5 or WinChip 11765065a706SMasanari Iida systems. These typically need to be enabled explicitly on the command 11774efc0670SAndi Kleen line. 11784efc0670SAndi Kleen 1179b2762686SAndi Kleenconfig X86_MCE_THRESHOLD 1180b2762686SAndi Kleen depends on X86_MCE_AMD || X86_MCE_INTEL 11816fc108a0SJan Beulich def_bool y 1182b2762686SAndi Kleen 1183ea149b36SAndi Kleenconfig X86_MCE_INJECT 1184bc8e80d5SBorislav Petkov depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1185ea149b36SAndi Kleen tristate "Machine check injector support" 1186a7f7f624SMasahiro Yamada help 1187ea149b36SAndi Kleen Provide support for injecting machine checks for testing purposes. 1188ea149b36SAndi Kleen If you don't know what a machine check is and you don't do kernel 1189ea149b36SAndi Kleen QA it is safe to say n. 1190ea149b36SAndi Kleen 119107dc900eSPeter Zijlstrasource "arch/x86/events/Kconfig" 1192e633c65aSKan Liang 11935aef51c3SAndy Lutomirskiconfig X86_LEGACY_VM86 11941e642812SIngo Molnar bool "Legacy VM86 support" 1195506f1d07SSam Ravnborg depends on X86_32 1196a7f7f624SMasahiro Yamada help 11975aef51c3SAndy Lutomirski This option allows user programs to put the CPU into V8086 11985aef51c3SAndy Lutomirski mode, which is an 80286-era approximation of 16-bit real mode. 11995aef51c3SAndy Lutomirski 12005aef51c3SAndy Lutomirski Some very old versions of X and/or vbetool require this option 12015aef51c3SAndy Lutomirski for user mode setting. Similarly, DOSEMU will use it if 12025aef51c3SAndy Lutomirski available to accelerate real mode DOS programs. However, any 12035aef51c3SAndy Lutomirski recent version of DOSEMU, X, or vbetool should be fully 12045aef51c3SAndy Lutomirski functional even without kernel VM86 support, as they will all 12051e642812SIngo Molnar fall back to software emulation. Nevertheless, if you are using 12061e642812SIngo Molnar a 16-bit DOS program where 16-bit performance matters, vm86 12071e642812SIngo Molnar mode might be faster than emulation and you might want to 12081e642812SIngo Molnar enable this option. 12095aef51c3SAndy Lutomirski 12101e642812SIngo Molnar Note that any app that works on a 64-bit kernel is unlikely to 12111e642812SIngo Molnar need this option, as 64-bit kernels don't, and can't, support 12121e642812SIngo Molnar V8086 mode. This option is also unrelated to 16-bit protected 12131e642812SIngo Molnar mode and is not needed to run most 16-bit programs under Wine. 12145aef51c3SAndy Lutomirski 12151e642812SIngo Molnar Enabling this option increases the complexity of the kernel 12161e642812SIngo Molnar and slows down exception handling a tiny bit. 12175aef51c3SAndy Lutomirski 12181e642812SIngo Molnar If unsure, say N here. 12195aef51c3SAndy Lutomirski 12205aef51c3SAndy Lutomirskiconfig VM86 12215aef51c3SAndy Lutomirski bool 12225aef51c3SAndy Lutomirski default X86_LEGACY_VM86 122334273f41SH. Peter Anvin 122434273f41SH. Peter Anvinconfig X86_16BIT 122534273f41SH. Peter Anvin bool "Enable support for 16-bit segments" if EXPERT 122634273f41SH. Peter Anvin default y 1227a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 1228a7f7f624SMasahiro Yamada help 122934273f41SH. Peter Anvin This option is required by programs like Wine to run 16-bit 123034273f41SH. Peter Anvin protected mode legacy code on x86 processors. Disabling 123134273f41SH. Peter Anvin this option saves about 300 bytes on i386, or around 6K text 123234273f41SH. Peter Anvin plus 16K runtime memory on x86-64, 123334273f41SH. Peter Anvin 123434273f41SH. Peter Anvinconfig X86_ESPFIX32 123534273f41SH. Peter Anvin def_bool y 123634273f41SH. Peter Anvin depends on X86_16BIT && X86_32 1237506f1d07SSam Ravnborg 1238197725deSH. Peter Anvinconfig X86_ESPFIX64 1239197725deSH. Peter Anvin def_bool y 124034273f41SH. Peter Anvin depends on X86_16BIT && X86_64 1241506f1d07SSam Ravnborg 12421ad83c85SAndy Lutomirskiconfig X86_VSYSCALL_EMULATION 12431ad83c85SAndy Lutomirski bool "Enable vsyscall emulation" if EXPERT 12441ad83c85SAndy Lutomirski default y 12451ad83c85SAndy Lutomirski depends on X86_64 1246a7f7f624SMasahiro Yamada help 12471ad83c85SAndy Lutomirski This enables emulation of the legacy vsyscall page. Disabling 12481ad83c85SAndy Lutomirski it is roughly equivalent to booting with vsyscall=none, except 12491ad83c85SAndy Lutomirski that it will also disable the helpful warning if a program 12501ad83c85SAndy Lutomirski tries to use a vsyscall. With this option set to N, offending 12511ad83c85SAndy Lutomirski programs will just segfault, citing addresses of the form 12521ad83c85SAndy Lutomirski 0xffffffffff600?00. 12531ad83c85SAndy Lutomirski 12541ad83c85SAndy Lutomirski This option is required by many programs built before 2013, and 12551ad83c85SAndy Lutomirski care should be used even with newer programs if set to N. 12561ad83c85SAndy Lutomirski 12571ad83c85SAndy Lutomirski Disabling this option saves about 7K of kernel size and 12581ad83c85SAndy Lutomirski possibly 4K of additional runtime pagetable memory. 12591ad83c85SAndy Lutomirski 1260111e7b15SThomas Gleixnerconfig X86_IOPL_IOPERM 1261111e7b15SThomas Gleixner bool "IOPERM and IOPL Emulation" 1262a24ca997SThomas Gleixner default y 1263a7f7f624SMasahiro Yamada help 1264111e7b15SThomas Gleixner This enables the ioperm() and iopl() syscalls which are necessary 1265111e7b15SThomas Gleixner for legacy applications. 1266111e7b15SThomas Gleixner 1267c8137aceSThomas Gleixner Legacy IOPL support is an overbroad mechanism which allows user 1268c8137aceSThomas Gleixner space aside of accessing all 65536 I/O ports also to disable 1269c8137aceSThomas Gleixner interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1270c8137aceSThomas Gleixner capabilities and permission from potentially active security 1271c8137aceSThomas Gleixner modules. 1272c8137aceSThomas Gleixner 1273c8137aceSThomas Gleixner The emulation restricts the functionality of the syscall to 1274c8137aceSThomas Gleixner only allowing the full range I/O port access, but prevents the 1275a24ca997SThomas Gleixner ability to disable interrupts from user space which would be 1276a24ca997SThomas Gleixner granted if the hardware IOPL mechanism would be used. 1277c8137aceSThomas Gleixner 1278506f1d07SSam Ravnborgconfig TOSHIBA 1279506f1d07SSam Ravnborg tristate "Toshiba Laptop support" 1280506f1d07SSam Ravnborg depends on X86_32 1281a7f7f624SMasahiro Yamada help 1282506f1d07SSam Ravnborg This adds a driver to safely access the System Management Mode of 1283506f1d07SSam Ravnborg the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1284506f1d07SSam Ravnborg not work on models with a Phoenix BIOS. The System Management Mode 1285506f1d07SSam Ravnborg is used to set the BIOS and power saving options on Toshiba portables. 1286506f1d07SSam Ravnborg 1287506f1d07SSam Ravnborg For information on utilities to make use of this driver see the 1288506f1d07SSam Ravnborg Toshiba Linux utilities web site at: 1289506f1d07SSam Ravnborg <http://www.buzzard.org.uk/toshiba/>. 1290506f1d07SSam Ravnborg 1291506f1d07SSam Ravnborg Say Y if you intend to run this kernel on a Toshiba portable. 1292506f1d07SSam Ravnborg Say N otherwise. 1293506f1d07SSam Ravnborg 1294506f1d07SSam Ravnborgconfig X86_REBOOTFIXUPS 12959ba16087SJan Beulich bool "Enable X86 board specific fixups for reboot" 12969ba16087SJan Beulich depends on X86_32 1297a7f7f624SMasahiro Yamada help 1298506f1d07SSam Ravnborg This enables chipset and/or board specific fixups to be done 1299506f1d07SSam Ravnborg in order to get reboot to work correctly. This is only needed on 1300506f1d07SSam Ravnborg some combinations of hardware and BIOS. The symptom, for which 1301506f1d07SSam Ravnborg this config is intended, is when reboot ends with a stalled/hung 1302506f1d07SSam Ravnborg system. 1303506f1d07SSam Ravnborg 1304506f1d07SSam Ravnborg Currently, the only fixup is for the Geode machines using 13055e3a77e9SFlorian Fainelli CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1306506f1d07SSam Ravnborg 1307506f1d07SSam Ravnborg Say Y if you want to enable the fixup. Currently, it's safe to 1308506f1d07SSam Ravnborg enable this option even if you don't need it. 1309506f1d07SSam Ravnborg Say N otherwise. 1310506f1d07SSam Ravnborg 1311506f1d07SSam Ravnborgconfig MICROCODE 13129a2bc335SBorislav Petkov bool "CPU microcode loading support" 13139a2bc335SBorislav Petkov default y 131480030e3dSBorislav Petkov depends on CPU_SUP_AMD || CPU_SUP_INTEL 1315a7f7f624SMasahiro Yamada help 1316506f1d07SSam Ravnborg If you say Y here, you will be able to update the microcode on 13175f9c01aaSBorislav Petkov Intel and AMD processors. The Intel support is for the IA32 family, 13185f9c01aaSBorislav Petkov e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 13195f9c01aaSBorislav Petkov AMD support is for families 0x10 and later. You will obviously need 13205f9c01aaSBorislav Petkov the actual microcode binary data itself which is not shipped with 13215f9c01aaSBorislav Petkov the Linux kernel. 1322506f1d07SSam Ravnborg 13235f9c01aaSBorislav Petkov The preferred method to load microcode from a detached initrd is described 1324ff61f079SJonathan Corbet in Documentation/arch/x86/microcode.rst. For that you need to enable 13255f9c01aaSBorislav Petkov CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 13265f9c01aaSBorislav Petkov initrd for microcode blobs. 1327506f1d07SSam Ravnborg 1328c508c46eSBenjamin Gilbert In addition, you can build the microcode into the kernel. For that you 1329c508c46eSBenjamin Gilbert need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1330c508c46eSBenjamin Gilbert config option. 1331506f1d07SSam Ravnborg 13328d86f390SPeter Orubaconfig MICROCODE_INTEL 1333e43f6e67SBorislav Petkov bool "Intel microcode loading support" 13349c55d99eSBorislav Petkov depends on CPU_SUP_INTEL && MICROCODE 13358d86f390SPeter Oruba default MICROCODE 1336a7f7f624SMasahiro Yamada help 13378d86f390SPeter Oruba This options enables microcode patch loading support for Intel 13388d86f390SPeter Oruba processors. 13398d86f390SPeter Oruba 1340b8989db9SAlan For the current Intel microcode data package go to 1341b8989db9SAlan <https://downloadcenter.intel.com> and search for 1342b8989db9SAlan 'Linux Processor Microcode Data File'. 13438d86f390SPeter Oruba 134480cc9f10SPeter Orubaconfig MICROCODE_AMD 1345e43f6e67SBorislav Petkov bool "AMD microcode loading support" 13469c55d99eSBorislav Petkov depends on CPU_SUP_AMD && MICROCODE 1347a7f7f624SMasahiro Yamada help 134880cc9f10SPeter Oruba If you select this option, microcode patch loading support for AMD 134980cc9f10SPeter Oruba processors will be enabled. 135080cc9f10SPeter Oruba 1351a77a94f8SBorislav Petkovconfig MICROCODE_LATE_LOADING 1352a77a94f8SBorislav Petkov bool "Late microcode loading (DANGEROUS)" 1353c02f48e0SBorislav Petkov default n 1354506f1d07SSam Ravnborg depends on MICROCODE 1355a7f7f624SMasahiro Yamada help 1356a77a94f8SBorislav Petkov Loading microcode late, when the system is up and executing instructions 1357a77a94f8SBorislav Petkov is a tricky business and should be avoided if possible. Just the sequence 1358a77a94f8SBorislav Petkov of synchronizing all cores and SMT threads is one fragile dance which does 1359a77a94f8SBorislav Petkov not guarantee that cores might not softlock after the loading. Therefore, 1360a77a94f8SBorislav Petkov use this at your own risk. Late loading taints the kernel too. 1361506f1d07SSam Ravnborg 1362506f1d07SSam Ravnborgconfig X86_MSR 1363506f1d07SSam Ravnborg tristate "/dev/cpu/*/msr - Model-specific register support" 1364a7f7f624SMasahiro Yamada help 1365506f1d07SSam Ravnborg This device gives privileged processes access to the x86 1366506f1d07SSam Ravnborg Model-Specific Registers (MSRs). It is a character device with 1367506f1d07SSam Ravnborg major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1368506f1d07SSam Ravnborg MSR accesses are directed to a specific CPU on multi-processor 1369506f1d07SSam Ravnborg systems. 1370506f1d07SSam Ravnborg 1371506f1d07SSam Ravnborgconfig X86_CPUID 1372506f1d07SSam Ravnborg tristate "/dev/cpu/*/cpuid - CPU information support" 1373a7f7f624SMasahiro Yamada help 1374506f1d07SSam Ravnborg This device gives processes access to the x86 CPUID instruction to 1375506f1d07SSam Ravnborg be executed on a specific processor. It is a character device 1376506f1d07SSam Ravnborg with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1377506f1d07SSam Ravnborg /dev/cpu/31/cpuid. 1378506f1d07SSam Ravnborg 1379506f1d07SSam Ravnborgchoice 1380506f1d07SSam Ravnborg prompt "High Memory Support" 13816fc108a0SJan Beulich default HIGHMEM4G 1382506f1d07SSam Ravnborg depends on X86_32 1383506f1d07SSam Ravnborg 1384506f1d07SSam Ravnborgconfig NOHIGHMEM 1385506f1d07SSam Ravnborg bool "off" 1386a7f7f624SMasahiro Yamada help 1387506f1d07SSam Ravnborg Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1388506f1d07SSam Ravnborg However, the address space of 32-bit x86 processors is only 4 1389506f1d07SSam Ravnborg Gigabytes large. That means that, if you have a large amount of 1390506f1d07SSam Ravnborg physical memory, not all of it can be "permanently mapped" by the 1391506f1d07SSam Ravnborg kernel. The physical memory that's not permanently mapped is called 1392506f1d07SSam Ravnborg "high memory". 1393506f1d07SSam Ravnborg 1394506f1d07SSam Ravnborg If you are compiling a kernel which will never run on a machine with 1395506f1d07SSam Ravnborg more than 1 Gigabyte total physical RAM, answer "off" here (default 1396506f1d07SSam Ravnborg choice and suitable for most users). This will result in a "3GB/1GB" 1397506f1d07SSam Ravnborg split: 3GB are mapped so that each process sees a 3GB virtual memory 1398506f1d07SSam Ravnborg space and the remaining part of the 4GB virtual memory space is used 1399506f1d07SSam Ravnborg by the kernel to permanently map as much physical memory as 1400506f1d07SSam Ravnborg possible. 1401506f1d07SSam Ravnborg 1402506f1d07SSam Ravnborg If the machine has between 1 and 4 Gigabytes physical RAM, then 1403506f1d07SSam Ravnborg answer "4GB" here. 1404506f1d07SSam Ravnborg 1405506f1d07SSam Ravnborg If more than 4 Gigabytes is used then answer "64GB" here. This 1406506f1d07SSam Ravnborg selection turns Intel PAE (Physical Address Extension) mode on. 1407506f1d07SSam Ravnborg PAE implements 3-level paging on IA32 processors. PAE is fully 1408506f1d07SSam Ravnborg supported by Linux, PAE mode is implemented on all recent Intel 1409506f1d07SSam Ravnborg processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1410506f1d07SSam Ravnborg then the kernel will not boot on CPUs that don't support PAE! 1411506f1d07SSam Ravnborg 1412506f1d07SSam Ravnborg The actual amount of total physical memory will either be 1413506f1d07SSam Ravnborg auto detected or can be forced by using a kernel command line option 1414506f1d07SSam Ravnborg such as "mem=256M". (Try "man bootparam" or see the documentation of 1415506f1d07SSam Ravnborg your boot loader (lilo or loadlin) about how to pass options to the 1416506f1d07SSam Ravnborg kernel at boot time.) 1417506f1d07SSam Ravnborg 1418506f1d07SSam Ravnborg If unsure, say "off". 1419506f1d07SSam Ravnborg 1420506f1d07SSam Ravnborgconfig HIGHMEM4G 1421506f1d07SSam Ravnborg bool "4GB" 1422a7f7f624SMasahiro Yamada help 1423506f1d07SSam Ravnborg Select this if you have a 32-bit processor and between 1 and 4 1424506f1d07SSam Ravnborg gigabytes of physical RAM. 1425506f1d07SSam Ravnborg 1426506f1d07SSam Ravnborgconfig HIGHMEM64G 1427506f1d07SSam Ravnborg bool "64GB" 1428225bac2dSLukas Bulwahn depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6 1429506f1d07SSam Ravnborg select X86_PAE 1430a7f7f624SMasahiro Yamada help 1431506f1d07SSam Ravnborg Select this if you have a 32-bit processor and more than 4 1432506f1d07SSam Ravnborg gigabytes of physical RAM. 1433506f1d07SSam Ravnborg 1434506f1d07SSam Ravnborgendchoice 1435506f1d07SSam Ravnborg 1436506f1d07SSam Ravnborgchoice 14376a108a14SDavid Rientjes prompt "Memory split" if EXPERT 1438506f1d07SSam Ravnborg default VMSPLIT_3G 1439506f1d07SSam Ravnborg depends on X86_32 1440a7f7f624SMasahiro Yamada help 1441506f1d07SSam Ravnborg Select the desired split between kernel and user memory. 1442506f1d07SSam Ravnborg 1443506f1d07SSam Ravnborg If the address range available to the kernel is less than the 1444506f1d07SSam Ravnborg physical memory installed, the remaining memory will be available 1445506f1d07SSam Ravnborg as "high memory". Accessing high memory is a little more costly 1446506f1d07SSam Ravnborg than low memory, as it needs to be mapped into the kernel first. 1447506f1d07SSam Ravnborg Note that increasing the kernel address space limits the range 1448506f1d07SSam Ravnborg available to user programs, making the address space there 1449506f1d07SSam Ravnborg tighter. Selecting anything other than the default 3G/1G split 1450506f1d07SSam Ravnborg will also likely make your kernel incompatible with binary-only 1451506f1d07SSam Ravnborg kernel modules. 1452506f1d07SSam Ravnborg 1453506f1d07SSam Ravnborg If you are not absolutely sure what you are doing, leave this 1454506f1d07SSam Ravnborg option alone! 1455506f1d07SSam Ravnborg 1456506f1d07SSam Ravnborg config VMSPLIT_3G 1457506f1d07SSam Ravnborg bool "3G/1G user/kernel split" 1458506f1d07SSam Ravnborg config VMSPLIT_3G_OPT 1459506f1d07SSam Ravnborg depends on !X86_PAE 1460506f1d07SSam Ravnborg bool "3G/1G user/kernel split (for full 1G low memory)" 1461506f1d07SSam Ravnborg config VMSPLIT_2G 1462506f1d07SSam Ravnborg bool "2G/2G user/kernel split" 1463506f1d07SSam Ravnborg config VMSPLIT_2G_OPT 1464506f1d07SSam Ravnborg depends on !X86_PAE 1465506f1d07SSam Ravnborg bool "2G/2G user/kernel split (for full 2G low memory)" 1466506f1d07SSam Ravnborg config VMSPLIT_1G 1467506f1d07SSam Ravnborg bool "1G/3G user/kernel split" 1468506f1d07SSam Ravnborgendchoice 1469506f1d07SSam Ravnborg 1470506f1d07SSam Ravnborgconfig PAGE_OFFSET 1471506f1d07SSam Ravnborg hex 1472506f1d07SSam Ravnborg default 0xB0000000 if VMSPLIT_3G_OPT 1473506f1d07SSam Ravnborg default 0x80000000 if VMSPLIT_2G 1474506f1d07SSam Ravnborg default 0x78000000 if VMSPLIT_2G_OPT 1475506f1d07SSam Ravnborg default 0x40000000 if VMSPLIT_1G 1476506f1d07SSam Ravnborg default 0xC0000000 1477506f1d07SSam Ravnborg depends on X86_32 1478506f1d07SSam Ravnborg 1479506f1d07SSam Ravnborgconfig HIGHMEM 14803c2362e6SHarvey Harrison def_bool y 1481506f1d07SSam Ravnborg depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1482506f1d07SSam Ravnborg 1483506f1d07SSam Ravnborgconfig X86_PAE 14849ba16087SJan Beulich bool "PAE (Physical Address Extension) Support" 1485506f1d07SSam Ravnborg depends on X86_32 && !HIGHMEM4G 1486d4a451d5SChristoph Hellwig select PHYS_ADDR_T_64BIT 14879d99c712SChristian Melki select SWIOTLB 1488a7f7f624SMasahiro Yamada help 1489506f1d07SSam Ravnborg PAE is required for NX support, and furthermore enables 1490506f1d07SSam Ravnborg larger swapspace support for non-overcommit purposes. It 1491506f1d07SSam Ravnborg has the cost of more pagetable lookup overhead, and also 1492506f1d07SSam Ravnborg consumes more pagetable space per process. 1493506f1d07SSam Ravnborg 149477ef56e4SKirill A. Shutemovconfig X86_5LEVEL 149577ef56e4SKirill A. Shutemov bool "Enable 5-level page tables support" 149618ec1eafSKirill A. Shutemov default y 1497eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 1498162434e7SKirill A. Shutemov select SPARSEMEM_VMEMMAP 149977ef56e4SKirill A. Shutemov depends on X86_64 1500a7f7f624SMasahiro Yamada help 150177ef56e4SKirill A. Shutemov 5-level paging enables access to larger address space: 150277ef56e4SKirill A. Shutemov up to 128 PiB of virtual address space and 4 PiB of 150377ef56e4SKirill A. Shutemov physical address space. 150477ef56e4SKirill A. Shutemov 150577ef56e4SKirill A. Shutemov It will be supported by future Intel CPUs. 150677ef56e4SKirill A. Shutemov 15076657fca0SKirill A. Shutemov A kernel with the option enabled can be booted on machines that 15086657fca0SKirill A. Shutemov support 4- or 5-level paging. 150977ef56e4SKirill A. Shutemov 1510ff61f079SJonathan Corbet See Documentation/arch/x86/x86_64/5level-paging.rst for more 151177ef56e4SKirill A. Shutemov information. 151277ef56e4SKirill A. Shutemov 151377ef56e4SKirill A. Shutemov Say N if unsure. 151477ef56e4SKirill A. Shutemov 151510971ab2SIngo Molnarconfig X86_DIRECT_GBPAGES 1516e5008abeSLuis R. Rodriguez def_bool y 15172e1da13fSVlastimil Babka depends on X86_64 1518a7f7f624SMasahiro Yamada help 151910971ab2SIngo Molnar Certain kernel features effectively disable kernel 152010971ab2SIngo Molnar linear 1 GB mappings (even if the CPU otherwise 152110971ab2SIngo Molnar supports them), so don't confuse the user by printing 152210971ab2SIngo Molnar that we have them enabled. 15239e899816SNick Piggin 15245c280cf6SThomas Gleixnerconfig X86_CPA_STATISTICS 15255c280cf6SThomas Gleixner bool "Enable statistic for Change Page Attribute" 15265c280cf6SThomas Gleixner depends on DEBUG_FS 1527a7f7f624SMasahiro Yamada help 1528b75baaf3SIngo Molnar Expose statistics about the Change Page Attribute mechanism, which 1529a943245aSColin Ian King helps to determine the effectiveness of preserving large and huge 15305c280cf6SThomas Gleixner page mappings when mapping protections are changed. 15315c280cf6SThomas Gleixner 153220f07a04SKirill A. Shutemovconfig X86_MEM_ENCRYPT 153320f07a04SKirill A. Shutemov select ARCH_HAS_FORCE_DMA_UNENCRYPTED 153420f07a04SKirill A. Shutemov select DYNAMIC_PHYSICAL_MASK 153520f07a04SKirill A. Shutemov def_bool n 153620f07a04SKirill A. Shutemov 15377744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT 15387744ccdbSTom Lendacky bool "AMD Secure Memory Encryption (SME) support" 15397744ccdbSTom Lendacky depends on X86_64 && CPU_SUP_AMD 15406c321179STom Lendacky depends on EFI_STUB 154182fef0adSDavid Rientjes select DMA_COHERENT_POOL 1542ce9084baSArd Biesheuvel select ARCH_USE_MEMREMAP_PROT 1543597cfe48SJoerg Roedel select INSTRUCTION_DECODER 1544aa5a4611STom Lendacky select ARCH_HAS_CC_PLATFORM 154520f07a04SKirill A. Shutemov select X86_MEM_ENCRYPT 15466c321179STom Lendacky select UNACCEPTED_MEMORY 1547a7f7f624SMasahiro Yamada help 15487744ccdbSTom Lendacky Say yes to enable support for the encryption of system memory. 15497744ccdbSTom Lendacky This requires an AMD processor that supports Secure Memory 15507744ccdbSTom Lendacky Encryption (SME). 15517744ccdbSTom Lendacky 15527744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 15537744ccdbSTom Lendacky bool "Activate AMD Secure Memory Encryption (SME) by default" 15547744ccdbSTom Lendacky depends on AMD_MEM_ENCRYPT 1555a7f7f624SMasahiro Yamada help 15567744ccdbSTom Lendacky Say yes to have system memory encrypted by default if running on 15577744ccdbSTom Lendacky an AMD processor that supports Secure Memory Encryption (SME). 15587744ccdbSTom Lendacky 15597744ccdbSTom Lendacky If set to Y, then the encryption of system memory can be 15607744ccdbSTom Lendacky deactivated with the mem_encrypt=off command line option. 15617744ccdbSTom Lendacky 15627744ccdbSTom Lendacky If set to N, then the encryption of system memory can be 15637744ccdbSTom Lendacky activated with the mem_encrypt=on command line option. 15647744ccdbSTom Lendacky 1565506f1d07SSam Ravnborg# Common NUMA Features 1566506f1d07SSam Ravnborgconfig NUMA 1567e133f6eaSRandy Dunlap bool "NUMA Memory Allocation and Scheduler Support" 1568506f1d07SSam Ravnborg depends on SMP 1569b5660ba7SH. Peter Anvin depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1570b5660ba7SH. Peter Anvin default y if X86_BIGSMP 15717ecd19cfSKefeng Wang select USE_PERCPU_NUMA_NODE_ID 1572a7f7f624SMasahiro Yamada help 1573e133f6eaSRandy Dunlap Enable NUMA (Non-Uniform Memory Access) support. 1574fd51b2d7SKOSAKI Motohiro 1575506f1d07SSam Ravnborg The kernel will try to allocate memory used by a CPU on the 1576506f1d07SSam Ravnborg local memory controller of the CPU and add some more 1577506f1d07SSam Ravnborg NUMA awareness to the kernel. 1578506f1d07SSam Ravnborg 1579c280ea5eSIngo Molnar For 64-bit this is recommended if the system is Intel Core i7 1580fd51b2d7SKOSAKI Motohiro (or later), AMD Opteron, or EM64T NUMA. 1581fd51b2d7SKOSAKI Motohiro 1582b5660ba7SH. Peter Anvin For 32-bit this is only needed if you boot a 32-bit 15837cf6c945SDavid Rientjes kernel on a 64-bit NUMA platform. 1584fd51b2d7SKOSAKI Motohiro 1585fd51b2d7SKOSAKI Motohiro Otherwise, you should say N. 1586506f1d07SSam Ravnborg 1587eec1d4faSHans Rosenfeldconfig AMD_NUMA 15883c2362e6SHarvey Harrison def_bool y 15893c2362e6SHarvey Harrison prompt "Old style AMD Opteron NUMA detection" 15905da0ef9aSTejun Heo depends on X86_64 && NUMA && PCI 1591a7f7f624SMasahiro Yamada help 1592eec1d4faSHans Rosenfeld Enable AMD NUMA node topology detection. You should say Y here if 1593eec1d4faSHans Rosenfeld you have a multi processor AMD system. This uses an old method to 1594eec1d4faSHans Rosenfeld read the NUMA configuration directly from the builtin Northbridge 1595eec1d4faSHans Rosenfeld of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1596eec1d4faSHans Rosenfeld which also takes priority if both are compiled in. 1597506f1d07SSam Ravnborg 1598506f1d07SSam Ravnborgconfig X86_64_ACPI_NUMA 15993c2362e6SHarvey Harrison def_bool y 16003c2362e6SHarvey Harrison prompt "ACPI NUMA detection" 1601506f1d07SSam Ravnborg depends on X86_64 && NUMA && ACPI && PCI 1602506f1d07SSam Ravnborg select ACPI_NUMA 1603a7f7f624SMasahiro Yamada help 1604506f1d07SSam Ravnborg Enable ACPI SRAT based node topology detection. 1605506f1d07SSam Ravnborg 1606506f1d07SSam Ravnborgconfig NUMA_EMU 1607506f1d07SSam Ravnborg bool "NUMA emulation" 16081b7e03efSTejun Heo depends on NUMA 1609a7f7f624SMasahiro Yamada help 1610506f1d07SSam Ravnborg Enable NUMA emulation. A flat machine will be split 1611506f1d07SSam Ravnborg into virtual nodes when booted with "numa=fake=N", where N is the 1612506f1d07SSam Ravnborg number of nodes. This is only useful for debugging. 1613506f1d07SSam Ravnborg 1614506f1d07SSam Ravnborgconfig NODES_SHIFT 1615d25e26b6SLinus Torvalds int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 161651591e31SDavid Rientjes range 1 10 161751591e31SDavid Rientjes default "10" if MAXSMP 1618506f1d07SSam Ravnborg default "6" if X86_64 1619506f1d07SSam Ravnborg default "3" 1620a9ee6cf5SMike Rapoport depends on NUMA 1621a7f7f624SMasahiro Yamada help 16221184dc2fSMike Travis Specify the maximum number of NUMA Nodes available on the target 1623692105b8SMatt LaPlante system. Increases memory reserved to accommodate various tables. 1624506f1d07SSam Ravnborg 1625506f1d07SSam Ravnborgconfig ARCH_FLATMEM_ENABLE 1626506f1d07SSam Ravnborg def_bool y 16273b16651fSTejun Heo depends on X86_32 && !NUMA 1628506f1d07SSam Ravnborg 1629506f1d07SSam Ravnborgconfig ARCH_SPARSEMEM_ENABLE 1630506f1d07SSam Ravnborg def_bool y 16316ea30386SKees Cook depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1632506f1d07SSam Ravnborg select SPARSEMEM_STATIC if X86_32 1633506f1d07SSam Ravnborg select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1634506f1d07SSam Ravnborg 16353b16651fSTejun Heoconfig ARCH_SPARSEMEM_DEFAULT 16366ad57f7fSMike Rapoport def_bool X86_64 || (NUMA && X86_32) 16373b16651fSTejun Heo 1638506f1d07SSam Ravnborgconfig ARCH_SELECT_MEMORY_MODEL 1639506f1d07SSam Ravnborg def_bool y 16404eda2bc3SDavid Hildenbrand depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE 1641506f1d07SSam Ravnborg 1642506f1d07SSam Ravnborgconfig ARCH_MEMORY_PROBE 1643a0842b70SToshi Kani bool "Enable sysfs memory/probe interface" 16445c11f00bSDavid Hildenbrand depends on MEMORY_HOTPLUG 1645a0842b70SToshi Kani help 1646a0842b70SToshi Kani This option enables a sysfs memory/probe interface for testing. 1647cb1aaebeSMauro Carvalho Chehab See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1648a0842b70SToshi Kani If you are unsure how to answer this question, answer N. 1649506f1d07SSam Ravnborg 16503b16651fSTejun Heoconfig ARCH_PROC_KCORE_TEXT 16513b16651fSTejun Heo def_bool y 16523b16651fSTejun Heo depends on X86_64 && PROC_KCORE 16533b16651fSTejun Heo 1654a29815a3SAvi Kivityconfig ILLEGAL_POINTER_VALUE 1655a29815a3SAvi Kivity hex 1656a29815a3SAvi Kivity default 0 if X86_32 1657a29815a3SAvi Kivity default 0xdead000000000000 if X86_64 1658a29815a3SAvi Kivity 16597a67832cSDan Williamsconfig X86_PMEM_LEGACY_DEVICE 16607a67832cSDan Williams bool 16617a67832cSDan Williams 1662ec776ef6SChristoph Hellwigconfig X86_PMEM_LEGACY 16637a67832cSDan Williams tristate "Support non-standard NVDIMMs and ADR protected memory" 16649f53f9faSDan Williams depends on PHYS_ADDR_T_64BIT 16659f53f9faSDan Williams depends on BLK_DEV 16667a67832cSDan Williams select X86_PMEM_LEGACY_DEVICE 16677b27a862SDan Williams select NUMA_KEEP_MEMINFO if NUMA 16689f53f9faSDan Williams select LIBNVDIMM 1669ec776ef6SChristoph Hellwig help 1670ec776ef6SChristoph Hellwig Treat memory marked using the non-standard e820 type of 12 as used 1671ec776ef6SChristoph Hellwig by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1672ec776ef6SChristoph Hellwig The kernel will offer these regions to the 'pmem' driver so 1673ec776ef6SChristoph Hellwig they can be used for persistent storage. 1674ec776ef6SChristoph Hellwig 1675ec776ef6SChristoph Hellwig Say Y if unsure. 1676ec776ef6SChristoph Hellwig 1677506f1d07SSam Ravnborgconfig HIGHPTE 1678506f1d07SSam Ravnborg bool "Allocate 3rd-level pagetables from highmem" 16796fc108a0SJan Beulich depends on HIGHMEM 1680a7f7f624SMasahiro Yamada help 1681506f1d07SSam Ravnborg The VM uses one page table entry for each page of physical memory. 1682506f1d07SSam Ravnborg For systems with a lot of RAM, this can be wasteful of precious 1683506f1d07SSam Ravnborg low memory. Setting this option will put user-space page table 1684506f1d07SSam Ravnborg entries in high memory. 1685506f1d07SSam Ravnborg 16869f077871SJeremy Fitzhardingeconfig X86_CHECK_BIOS_CORRUPTION 16879f077871SJeremy Fitzhardinge bool "Check for low memory corruption" 1688a7f7f624SMasahiro Yamada help 16899f077871SJeremy Fitzhardinge Periodically check for memory corruption in low memory, which 16909f077871SJeremy Fitzhardinge is suspected to be caused by BIOS. Even when enabled in the 16919f077871SJeremy Fitzhardinge configuration, it is disabled at runtime. Enable it by 16929f077871SJeremy Fitzhardinge setting "memory_corruption_check=1" on the kernel command 16939f077871SJeremy Fitzhardinge line. By default it scans the low 64k of memory every 60 16949f077871SJeremy Fitzhardinge seconds; see the memory_corruption_check_size and 16959f077871SJeremy Fitzhardinge memory_corruption_check_period parameters in 16968c27ceffSMauro Carvalho Chehab Documentation/admin-guide/kernel-parameters.rst to adjust this. 16979f077871SJeremy Fitzhardinge 16989f077871SJeremy Fitzhardinge When enabled with the default parameters, this option has 16999f077871SJeremy Fitzhardinge almost no overhead, as it reserves a relatively small amount 17009f077871SJeremy Fitzhardinge of memory and scans it infrequently. It both detects corruption 17019f077871SJeremy Fitzhardinge and prevents it from affecting the running system. 17029f077871SJeremy Fitzhardinge 17039f077871SJeremy Fitzhardinge It is, however, intended as a diagnostic tool; if repeatable 17049f077871SJeremy Fitzhardinge BIOS-originated corruption always affects the same memory, 17059f077871SJeremy Fitzhardinge you can use memmap= to prevent the kernel from using that 17069f077871SJeremy Fitzhardinge memory. 17079f077871SJeremy Fitzhardinge 1708c885df50SJeremy Fitzhardingeconfig X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1709c885df50SJeremy Fitzhardinge bool "Set the default setting of memory_corruption_check" 1710c885df50SJeremy Fitzhardinge depends on X86_CHECK_BIOS_CORRUPTION 1711c885df50SJeremy Fitzhardinge default y 1712a7f7f624SMasahiro Yamada help 1713c885df50SJeremy Fitzhardinge Set whether the default state of memory_corruption_check is 1714c885df50SJeremy Fitzhardinge on or off. 1715c885df50SJeremy Fitzhardinge 1716506f1d07SSam Ravnborgconfig MATH_EMULATION 1717506f1d07SSam Ravnborg bool 1718a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 171987d6021bSArnd Bergmann prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1720a7f7f624SMasahiro Yamada help 1721506f1d07SSam Ravnborg Linux can emulate a math coprocessor (used for floating point 1722506f1d07SSam Ravnborg operations) if you don't have one. 486DX and Pentium processors have 1723506f1d07SSam Ravnborg a math coprocessor built in, 486SX and 386 do not, unless you added 1724506f1d07SSam Ravnborg a 487DX or 387, respectively. (The messages during boot time can 1725506f1d07SSam Ravnborg give you some hints here ["man dmesg"].) Everyone needs either a 1726506f1d07SSam Ravnborg coprocessor or this emulation. 1727506f1d07SSam Ravnborg 1728506f1d07SSam Ravnborg If you don't have a math coprocessor, you need to say Y here; if you 1729506f1d07SSam Ravnborg say Y here even though you have a coprocessor, the coprocessor will 1730506f1d07SSam Ravnborg be used nevertheless. (This behavior can be changed with the kernel 1731506f1d07SSam Ravnborg command line option "no387", which comes handy if your coprocessor 1732506f1d07SSam Ravnborg is broken. Try "man bootparam" or see the documentation of your boot 1733506f1d07SSam Ravnborg loader (lilo or loadlin) about how to pass options to the kernel at 1734506f1d07SSam Ravnborg boot time.) This means that it is a good idea to say Y here if you 1735506f1d07SSam Ravnborg intend to use this kernel on different machines. 1736506f1d07SSam Ravnborg 1737506f1d07SSam Ravnborg More information about the internals of the Linux math coprocessor 1738506f1d07SSam Ravnborg emulation can be found in <file:arch/x86/math-emu/README>. 1739506f1d07SSam Ravnborg 1740506f1d07SSam Ravnborg If you are not sure, say Y; apart from resulting in a 66 KB bigger 1741506f1d07SSam Ravnborg kernel, it won't hurt. 1742506f1d07SSam Ravnborg 1743506f1d07SSam Ravnborgconfig MTRR 17446fc108a0SJan Beulich def_bool y 17456a108a14SDavid Rientjes prompt "MTRR (Memory Type Range Register) support" if EXPERT 1746a7f7f624SMasahiro Yamada help 1747506f1d07SSam Ravnborg On Intel P6 family processors (Pentium Pro, Pentium II and later) 1748506f1d07SSam Ravnborg the Memory Type Range Registers (MTRRs) may be used to control 1749506f1d07SSam Ravnborg processor access to memory ranges. This is most useful if you have 1750506f1d07SSam Ravnborg a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1751506f1d07SSam Ravnborg allows bus write transfers to be combined into a larger transfer 1752506f1d07SSam Ravnborg before bursting over the PCI/AGP bus. This can increase performance 1753506f1d07SSam Ravnborg of image write operations 2.5 times or more. Saying Y here creates a 1754506f1d07SSam Ravnborg /proc/mtrr file which may be used to manipulate your processor's 1755506f1d07SSam Ravnborg MTRRs. Typically the X server should use this. 1756506f1d07SSam Ravnborg 1757506f1d07SSam Ravnborg This code has a reasonably generic interface so that similar 1758506f1d07SSam Ravnborg control registers on other processors can be easily supported 1759506f1d07SSam Ravnborg as well: 1760506f1d07SSam Ravnborg 1761506f1d07SSam Ravnborg The Cyrix 6x86, 6x86MX and M II processors have Address Range 1762506f1d07SSam Ravnborg Registers (ARRs) which provide a similar functionality to MTRRs. For 1763506f1d07SSam Ravnborg these, the ARRs are used to emulate the MTRRs. 1764506f1d07SSam Ravnborg The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1765506f1d07SSam Ravnborg MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1766506f1d07SSam Ravnborg write-combining. All of these processors are supported by this code 1767506f1d07SSam Ravnborg and it makes sense to say Y here if you have one of them. 1768506f1d07SSam Ravnborg 1769506f1d07SSam Ravnborg Saying Y here also fixes a problem with buggy SMP BIOSes which only 1770506f1d07SSam Ravnborg set the MTRRs for the boot CPU and not for the secondary CPUs. This 1771506f1d07SSam Ravnborg can lead to all sorts of problems, so it's good to say Y here. 1772506f1d07SSam Ravnborg 1773506f1d07SSam Ravnborg You can safely say Y even if your machine doesn't have MTRRs, you'll 1774506f1d07SSam Ravnborg just add about 9 KB to your kernel. 1775506f1d07SSam Ravnborg 1776ff61f079SJonathan Corbet See <file:Documentation/arch/x86/mtrr.rst> for more information. 1777506f1d07SSam Ravnborg 177895ffa243SYinghai Luconfig MTRR_SANITIZER 17792ffb3501SYinghai Lu def_bool y 178095ffa243SYinghai Lu prompt "MTRR cleanup support" 178195ffa243SYinghai Lu depends on MTRR 1782a7f7f624SMasahiro Yamada help 1783aba3728cSThomas Gleixner Convert MTRR layout from continuous to discrete, so X drivers can 1784aba3728cSThomas Gleixner add writeback entries. 178595ffa243SYinghai Lu 1786aba3728cSThomas Gleixner Can be disabled with disable_mtrr_cleanup on the kernel command line. 1787692105b8SMatt LaPlante The largest mtrr entry size for a continuous block can be set with 1788aba3728cSThomas Gleixner mtrr_chunk_size. 178995ffa243SYinghai Lu 17902ffb3501SYinghai Lu If unsure, say Y. 179195ffa243SYinghai Lu 179295ffa243SYinghai Luconfig MTRR_SANITIZER_ENABLE_DEFAULT 1793f5098d62SYinghai Lu int "MTRR cleanup enable value (0-1)" 1794f5098d62SYinghai Lu range 0 1 1795f5098d62SYinghai Lu default "0" 179695ffa243SYinghai Lu depends on MTRR_SANITIZER 1797a7f7f624SMasahiro Yamada help 1798f5098d62SYinghai Lu Enable mtrr cleanup default value 179995ffa243SYinghai Lu 180012031a62SYinghai Luconfig MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 180112031a62SYinghai Lu int "MTRR cleanup spare reg num (0-7)" 180212031a62SYinghai Lu range 0 7 180312031a62SYinghai Lu default "1" 180412031a62SYinghai Lu depends on MTRR_SANITIZER 1805a7f7f624SMasahiro Yamada help 180612031a62SYinghai Lu mtrr cleanup spare entries default, it can be changed via 1807aba3728cSThomas Gleixner mtrr_spare_reg_nr=N on the kernel command line. 180812031a62SYinghai Lu 18092e5d9c85Svenkatesh.pallipadi@intel.comconfig X86_PAT 18106fc108a0SJan Beulich def_bool y 18116a108a14SDavid Rientjes prompt "x86 PAT support" if EXPERT 18122a8a2719SIngo Molnar depends on MTRR 1813a7f7f624SMasahiro Yamada help 18142e5d9c85Svenkatesh.pallipadi@intel.com Use PAT attributes to setup page level cache control. 1815042b78e4SVenki Pallipadi 18162e5d9c85Svenkatesh.pallipadi@intel.com PATs are the modern equivalents of MTRRs and are much more 18172e5d9c85Svenkatesh.pallipadi@intel.com flexible than MTRRs. 18182e5d9c85Svenkatesh.pallipadi@intel.com 18192e5d9c85Svenkatesh.pallipadi@intel.com Say N here if you see bootup problems (boot crash, boot hang, 1820042b78e4SVenki Pallipadi spontaneous reboots) or a non-working video driver. 18212e5d9c85Svenkatesh.pallipadi@intel.com 18222e5d9c85Svenkatesh.pallipadi@intel.com If unsure, say Y. 18232e5d9c85Svenkatesh.pallipadi@intel.com 182446cf98cdSVenkatesh Pallipadiconfig ARCH_USES_PG_UNCACHED 182546cf98cdSVenkatesh Pallipadi def_bool y 182646cf98cdSVenkatesh Pallipadi depends on X86_PAT 182746cf98cdSVenkatesh Pallipadi 1828b971880fSBabu Mogerconfig X86_UMIP 1829796ebc81SRicardo Neri def_bool y 1830b971880fSBabu Moger prompt "User Mode Instruction Prevention" if EXPERT 1831a7f7f624SMasahiro Yamada help 1832b971880fSBabu Moger User Mode Instruction Prevention (UMIP) is a security feature in 1833b971880fSBabu Moger some x86 processors. If enabled, a general protection fault is 1834b971880fSBabu Moger issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1835b971880fSBabu Moger executed in user mode. These instructions unnecessarily expose 1836b971880fSBabu Moger information about the hardware state. 1837796ebc81SRicardo Neri 1838796ebc81SRicardo Neri The vast majority of applications do not use these instructions. 1839796ebc81SRicardo Neri For the very few that do, software emulation is provided in 1840796ebc81SRicardo Neri specific cases in protected and virtual-8086 modes. Emulated 1841796ebc81SRicardo Neri results are dummy. 1842aa35f896SRicardo Neri 1843156ff4a5SPeter Zijlstraconfig CC_HAS_IBT 1844156ff4a5SPeter Zijlstra # GCC >= 9 and binutils >= 2.29 1845156ff4a5SPeter Zijlstra # Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654 1846156ff4a5SPeter Zijlstra # Clang/LLVM >= 14 1847262448f3SNathan Chancellor # https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f 1848262448f3SNathan Chancellor # https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332 1849156ff4a5SPeter Zijlstra def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \ 1850262448f3SNathan Chancellor (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \ 1851156ff4a5SPeter Zijlstra $(as-instr,endbr64) 1852156ff4a5SPeter Zijlstra 1853156ff4a5SPeter Zijlstraconfig X86_KERNEL_IBT 1854156ff4a5SPeter Zijlstra prompt "Indirect Branch Tracking" 18554fd5f70cSKees Cook def_bool y 185603f16cd0SJosh Poimboeuf depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL 1857f6a2c2b2SNathan Chancellor # https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f 1858f6a2c2b2SNathan Chancellor depends on !LD_IS_LLD || LLD_VERSION >= 140000 185903f16cd0SJosh Poimboeuf select OBJTOOL 1860156ff4a5SPeter Zijlstra help 1861156ff4a5SPeter Zijlstra Build the kernel with support for Indirect Branch Tracking, a 1862156ff4a5SPeter Zijlstra hardware support course-grain forward-edge Control Flow Integrity 1863156ff4a5SPeter Zijlstra protection. It enforces that all indirect calls must land on 1864156ff4a5SPeter Zijlstra an ENDBR instruction, as such, the compiler will instrument the 1865156ff4a5SPeter Zijlstra code with them to make this happen. 1866156ff4a5SPeter Zijlstra 1867ed53a0d9SPeter Zijlstra In addition to building the kernel with IBT, seal all functions that 18684cdfc11bSNur Hussein are not indirect call targets, avoiding them ever becoming one. 1869ed53a0d9SPeter Zijlstra 1870ed53a0d9SPeter Zijlstra This requires LTO like objtool runs and will slow down the build. It 1871ed53a0d9SPeter Zijlstra does significantly reduce the number of ENDBR instructions in the 1872ed53a0d9SPeter Zijlstra kernel image. 1873ed53a0d9SPeter Zijlstra 187435e97790SDave Hansenconfig X86_INTEL_MEMORY_PROTECTION_KEYS 187538f3e775SBabu Moger prompt "Memory Protection Keys" 187635e97790SDave Hansen def_bool y 1877284244a9SDave Hansen # Note: only available in 64-bit mode 187838f3e775SBabu Moger depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 187952c8e601SIngo Molnar select ARCH_USES_HIGH_VMA_FLAGS 188052c8e601SIngo Molnar select ARCH_HAS_PKEYS 1881a7f7f624SMasahiro Yamada help 1882284244a9SDave Hansen Memory Protection Keys provides a mechanism for enforcing 1883284244a9SDave Hansen page-based protections, but without requiring modification of the 1884284244a9SDave Hansen page tables when an application changes protection domains. 1885284244a9SDave Hansen 18861eecbcdcSMauro Carvalho Chehab For details, see Documentation/core-api/protection-keys.rst 1887284244a9SDave Hansen 1888284244a9SDave Hansen If unsure, say y. 188935e97790SDave Hansen 1890db616173SMichal Hockochoice 1891db616173SMichal Hocko prompt "TSX enable mode" 1892db616173SMichal Hocko depends on CPU_SUP_INTEL 1893db616173SMichal Hocko default X86_INTEL_TSX_MODE_OFF 1894db616173SMichal Hocko help 1895db616173SMichal Hocko Intel's TSX (Transactional Synchronization Extensions) feature 1896db616173SMichal Hocko allows to optimize locking protocols through lock elision which 1897db616173SMichal Hocko can lead to a noticeable performance boost. 1898db616173SMichal Hocko 1899db616173SMichal Hocko On the other hand it has been shown that TSX can be exploited 1900db616173SMichal Hocko to form side channel attacks (e.g. TAA) and chances are there 1901db616173SMichal Hocko will be more of those attacks discovered in the future. 1902db616173SMichal Hocko 1903db616173SMichal Hocko Therefore TSX is not enabled by default (aka tsx=off). An admin 1904db616173SMichal Hocko might override this decision by tsx=on the command line parameter. 1905db616173SMichal Hocko Even with TSX enabled, the kernel will attempt to enable the best 1906db616173SMichal Hocko possible TAA mitigation setting depending on the microcode available 1907db616173SMichal Hocko for the particular machine. 1908db616173SMichal Hocko 1909db616173SMichal Hocko This option allows to set the default tsx mode between tsx=on, =off 1910db616173SMichal Hocko and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1911db616173SMichal Hocko details. 1912db616173SMichal Hocko 1913db616173SMichal Hocko Say off if not sure, auto if TSX is in use but it should be used on safe 1914db616173SMichal Hocko platforms or on if TSX is in use and the security aspect of tsx is not 1915db616173SMichal Hocko relevant. 1916db616173SMichal Hocko 1917db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_OFF 1918db616173SMichal Hocko bool "off" 1919db616173SMichal Hocko help 1920db616173SMichal Hocko TSX is disabled if possible - equals to tsx=off command line parameter. 1921db616173SMichal Hocko 1922db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_ON 1923db616173SMichal Hocko bool "on" 1924db616173SMichal Hocko help 1925db616173SMichal Hocko TSX is always enabled on TSX capable HW - equals the tsx=on command 1926db616173SMichal Hocko line parameter. 1927db616173SMichal Hocko 1928db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_AUTO 1929db616173SMichal Hocko bool "auto" 1930db616173SMichal Hocko help 1931db616173SMichal Hocko TSX is enabled on TSX capable HW that is believed to be safe against 1932db616173SMichal Hocko side channel attacks- equals the tsx=auto command line parameter. 1933db616173SMichal Hockoendchoice 1934db616173SMichal Hocko 1935e7e05452SSean Christophersonconfig X86_SGX 1936e7e05452SSean Christopherson bool "Software Guard eXtensions (SGX)" 1937b8d1d163SDaniel Sneddon depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC 1938e7e05452SSean Christopherson depends on CRYPTO=y 1939e7e05452SSean Christopherson depends on CRYPTO_SHA256=y 1940e7e05452SSean Christopherson select MMU_NOTIFIER 1941901ddbb9SJarkko Sakkinen select NUMA_KEEP_MEMINFO if NUMA 194240e0e784STony Luck select XARRAY_MULTI 1943e7e05452SSean Christopherson help 1944e7e05452SSean Christopherson Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1945e7e05452SSean Christopherson that can be used by applications to set aside private regions of code 1946e7e05452SSean Christopherson and data, referred to as enclaves. An enclave's private memory can 1947e7e05452SSean Christopherson only be accessed by code running within the enclave. Accesses from 1948e7e05452SSean Christopherson outside the enclave, including other enclaves, are disallowed by 1949e7e05452SSean Christopherson hardware. 1950e7e05452SSean Christopherson 1951e7e05452SSean Christopherson If unsure, say N. 1952e7e05452SSean Christopherson 1953506f1d07SSam Ravnborgconfig EFI 19549ba16087SJan Beulich bool "EFI runtime service support" 19555b83683fSHuang, Ying depends on ACPI 1956f6ce5002SSergey Vlasov select UCS2_STRING 1957022ee6c5SArd Biesheuvel select EFI_RUNTIME_WRAPPERS 19581ff2fc02STom Lendacky select ARCH_USE_MEMREMAP_PROT 1959a7f7f624SMasahiro Yamada help 19608b2cb7a8SHuang, Ying This enables the kernel to use EFI runtime services that are 1961506f1d07SSam Ravnborg available (such as the EFI variable services). 1962506f1d07SSam Ravnborg 19638b2cb7a8SHuang, Ying This option is only useful on systems that have EFI firmware. 19648b2cb7a8SHuang, Ying In addition, you should use the latest ELILO loader available 19658b2cb7a8SHuang, Ying at <http://elilo.sourceforge.net> in order to take advantage 19668b2cb7a8SHuang, Ying of EFI runtime services. However, even with this option, the 19678b2cb7a8SHuang, Ying resultant kernel should continue to boot on existing non-EFI 19688b2cb7a8SHuang, Ying platforms. 1969506f1d07SSam Ravnborg 1970291f3632SMatt Flemingconfig EFI_STUB 1971291f3632SMatt Fleming bool "EFI stub support" 1972c6dbd3e5SPeter Zijlstra depends on EFI 19737b2a583aSMatt Fleming select RELOCATABLE 1974a7f7f624SMasahiro Yamada help 1975291f3632SMatt Fleming This kernel feature allows a bzImage to be loaded directly 1976291f3632SMatt Fleming by EFI firmware without the use of a bootloader. 1977291f3632SMatt Fleming 19784f4cfa6cSMauro Carvalho Chehab See Documentation/admin-guide/efi-stub.rst for more information. 19790c759662SMatt Fleming 1980cc3fdda2SArd Biesheuvelconfig EFI_HANDOVER_PROTOCOL 1981cc3fdda2SArd Biesheuvel bool "EFI handover protocol (DEPRECATED)" 1982cc3fdda2SArd Biesheuvel depends on EFI_STUB 1983cc3fdda2SArd Biesheuvel default y 1984cc3fdda2SArd Biesheuvel help 1985cc3fdda2SArd Biesheuvel Select this in order to include support for the deprecated EFI 1986cc3fdda2SArd Biesheuvel handover protocol, which defines alternative entry points into the 1987cc3fdda2SArd Biesheuvel EFI stub. This is a practice that has no basis in the UEFI 1988cc3fdda2SArd Biesheuvel specification, and requires a priori knowledge on the part of the 1989cc3fdda2SArd Biesheuvel bootloader about Linux/x86 specific ways of passing the command line 1990cc3fdda2SArd Biesheuvel and initrd, and where in memory those assets may be loaded. 1991cc3fdda2SArd Biesheuvel 1992cc3fdda2SArd Biesheuvel If in doubt, say Y. Even though the corresponding support is not 1993cc3fdda2SArd Biesheuvel present in upstream GRUB or other bootloaders, most distros build 1994cc3fdda2SArd Biesheuvel GRUB with numerous downstream patches applied, and may rely on the 1995cc3fdda2SArd Biesheuvel handover protocol as as result. 1996cc3fdda2SArd Biesheuvel 19977d453eeeSMatt Flemingconfig EFI_MIXED 19987d453eeeSMatt Fleming bool "EFI mixed-mode support" 19997d453eeeSMatt Fleming depends on EFI_STUB && X86_64 2000a7f7f624SMasahiro Yamada help 20017d453eeeSMatt Fleming Enabling this feature allows a 64-bit kernel to be booted 20027d453eeeSMatt Fleming on a 32-bit firmware, provided that your CPU supports 64-bit 20037d453eeeSMatt Fleming mode. 20047d453eeeSMatt Fleming 20057d453eeeSMatt Fleming Note that it is not possible to boot a mixed-mode enabled 20067d453eeeSMatt Fleming kernel via the EFI boot stub - a bootloader that supports 20077d453eeeSMatt Fleming the EFI handover protocol must be used. 20087d453eeeSMatt Fleming 20097d453eeeSMatt Fleming If unsure, say N. 20107d453eeeSMatt Fleming 20114059ba65SArd Biesheuvelconfig EFI_FAKE_MEMMAP 20124059ba65SArd Biesheuvel bool "Enable EFI fake memory map" 20134059ba65SArd Biesheuvel depends on EFI 20144059ba65SArd Biesheuvel help 20154059ba65SArd Biesheuvel Saying Y here will enable "efi_fake_mem" boot option. By specifying 20164059ba65SArd Biesheuvel this parameter, you can add arbitrary attribute to specific memory 20174059ba65SArd Biesheuvel range by updating original (firmware provided) EFI memmap. This is 20184059ba65SArd Biesheuvel useful for debugging of EFI memmap related feature, e.g., Address 20194059ba65SArd Biesheuvel Range Mirroring feature. 20204059ba65SArd Biesheuvel 20214059ba65SArd Biesheuvelconfig EFI_MAX_FAKE_MEM 20224059ba65SArd Biesheuvel int "maximum allowable number of ranges in efi_fake_mem boot option" 20234059ba65SArd Biesheuvel depends on EFI_FAKE_MEMMAP 20244059ba65SArd Biesheuvel range 1 128 20254059ba65SArd Biesheuvel default 8 20264059ba65SArd Biesheuvel help 20274059ba65SArd Biesheuvel Maximum allowable number of ranges in efi_fake_mem boot option. 20284059ba65SArd Biesheuvel Ranges can be set up to this value using comma-separated list. 20294059ba65SArd Biesheuvel The default value is 8. 20304059ba65SArd Biesheuvel 20311fff234dSArd Biesheuvelconfig EFI_RUNTIME_MAP 20321fff234dSArd Biesheuvel bool "Export EFI runtime maps to sysfs" if EXPERT 20331fff234dSArd Biesheuvel depends on EFI 20341fff234dSArd Biesheuvel default KEXEC_CORE 20351fff234dSArd Biesheuvel help 20361fff234dSArd Biesheuvel Export EFI runtime memory regions to /sys/firmware/efi/runtime-map. 20371fff234dSArd Biesheuvel That memory map is required by the 2nd kernel to set up EFI virtual 20381fff234dSArd Biesheuvel mappings after kexec, but can also be used for debugging purposes. 20391fff234dSArd Biesheuvel 20401fff234dSArd Biesheuvel See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map. 20411fff234dSArd Biesheuvel 20428636a1f9SMasahiro Yamadasource "kernel/Kconfig.hz" 2043506f1d07SSam Ravnborg 2044506f1d07SSam Ravnborgconfig KEXEC 2045506f1d07SSam Ravnborg bool "kexec system call" 20462965faa5SDave Young select KEXEC_CORE 2047a7f7f624SMasahiro Yamada help 2048506f1d07SSam Ravnborg kexec is a system call that implements the ability to shutdown your 2049506f1d07SSam Ravnborg current kernel, and to start another kernel. It is like a reboot 2050506f1d07SSam Ravnborg but it is independent of the system firmware. And like a reboot 2051506f1d07SSam Ravnborg you can start any kernel with it, not just Linux. 2052506f1d07SSam Ravnborg 2053506f1d07SSam Ravnborg The name comes from the similarity to the exec system call. 2054506f1d07SSam Ravnborg 2055506f1d07SSam Ravnborg It is an ongoing process to be certain the hardware in a machine 2056506f1d07SSam Ravnborg is properly shutdown, so do not be surprised if this code does not 2057bf220695SGeert Uytterhoeven initially work for you. As of this writing the exact hardware 2058bf220695SGeert Uytterhoeven interface is strongly in flux, so no good recommendation can be 2059bf220695SGeert Uytterhoeven made. 2060506f1d07SSam Ravnborg 206174ca317cSVivek Goyalconfig KEXEC_FILE 206274ca317cSVivek Goyal bool "kexec file based system call" 20632965faa5SDave Young select KEXEC_CORE 2064b69a2afdSJonathan McDowell select HAVE_IMA_KEXEC if IMA 206574ca317cSVivek Goyal depends on X86_64 206674ca317cSVivek Goyal depends on CRYPTO=y 206774ca317cSVivek Goyal depends on CRYPTO_SHA256=y 2068a7f7f624SMasahiro Yamada help 206974ca317cSVivek Goyal This is new version of kexec system call. This system call is 207074ca317cSVivek Goyal file based and takes file descriptors as system call argument 207174ca317cSVivek Goyal for kernel and initramfs as opposed to list of segments as 207274ca317cSVivek Goyal accepted by previous system call. 207374ca317cSVivek Goyal 2074b799a09fSAKASHI Takahiroconfig ARCH_HAS_KEXEC_PURGATORY 2075b799a09fSAKASHI Takahiro def_bool KEXEC_FILE 2076b799a09fSAKASHI Takahiro 207799d5cadfSJiri Bohacconfig KEXEC_SIG 20788e7d8381SVivek Goyal bool "Verify kernel signature during kexec_file_load() syscall" 207974ca317cSVivek Goyal depends on KEXEC_FILE 2080a7f7f624SMasahiro Yamada help 208199d5cadfSJiri Bohac 208299d5cadfSJiri Bohac This option makes the kexec_file_load() syscall check for a valid 208399d5cadfSJiri Bohac signature of the kernel image. The image can still be loaded without 208499d5cadfSJiri Bohac a valid signature unless you also enable KEXEC_SIG_FORCE, though if 208599d5cadfSJiri Bohac there's a signature that we can check, then it must be valid. 208699d5cadfSJiri Bohac 208799d5cadfSJiri Bohac In addition to this option, you need to enable signature 208899d5cadfSJiri Bohac verification for the corresponding kernel image type being 208999d5cadfSJiri Bohac loaded in order for this to work. 209099d5cadfSJiri Bohac 209199d5cadfSJiri Bohacconfig KEXEC_SIG_FORCE 209299d5cadfSJiri Bohac bool "Require a valid signature in kexec_file_load() syscall" 209399d5cadfSJiri Bohac depends on KEXEC_SIG 2094a7f7f624SMasahiro Yamada help 20958e7d8381SVivek Goyal This option makes kernel signature verification mandatory for 2096d8eb8940SBorislav Petkov the kexec_file_load() syscall. 20978e7d8381SVivek Goyal 20988e7d8381SVivek Goyalconfig KEXEC_BZIMAGE_VERIFY_SIG 20998e7d8381SVivek Goyal bool "Enable bzImage signature verification support" 210099d5cadfSJiri Bohac depends on KEXEC_SIG 21018e7d8381SVivek Goyal depends on SIGNED_PE_FILE_VERIFICATION 21028e7d8381SVivek Goyal select SYSTEM_TRUSTED_KEYRING 2103a7f7f624SMasahiro Yamada help 21048e7d8381SVivek Goyal Enable bzImage signature verification support. 21058e7d8381SVivek Goyal 2106506f1d07SSam Ravnborgconfig CRASH_DUMP 210704b69447SPavel Machek bool "kernel crash dumps" 2108506f1d07SSam Ravnborg depends on X86_64 || (X86_32 && HIGHMEM) 2109a7f7f624SMasahiro Yamada help 2110506f1d07SSam Ravnborg Generate crash dump after being started by kexec. 2111506f1d07SSam Ravnborg This should be normally only set in special crash dump kernels 2112506f1d07SSam Ravnborg which are loaded in the main kernel with kexec-tools into 2113506f1d07SSam Ravnborg a specially reserved region and then later executed after 2114506f1d07SSam Ravnborg a crash by kdump/kexec. The crash dump kernel must be compiled 2115506f1d07SSam Ravnborg to a memory address not used by the main kernel or BIOS using 2116506f1d07SSam Ravnborg PHYSICAL_START, or it must be built as a relocatable image 2117506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y). 2118330d4810SMauro Carvalho Chehab For more details see Documentation/admin-guide/kdump/kdump.rst 2119506f1d07SSam Ravnborg 21203ab83521SHuang Yingconfig KEXEC_JUMP 21216ea30386SKees Cook bool "kexec jump" 2122fee7b0d8SHuang Ying depends on KEXEC && HIBERNATION 2123a7f7f624SMasahiro Yamada help 212489081d17SHuang Ying Jump between original kernel and kexeced kernel and invoke 212589081d17SHuang Ying code in physical address mode via KEXEC 21263ab83521SHuang Ying 2127506f1d07SSam Ravnborgconfig PHYSICAL_START 21286a108a14SDavid Rientjes hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2129ceefccc9SH. Peter Anvin default "0x1000000" 2130a7f7f624SMasahiro Yamada help 2131506f1d07SSam Ravnborg This gives the physical address where the kernel is loaded. 2132506f1d07SSam Ravnborg 2133506f1d07SSam Ravnborg If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2134506f1d07SSam Ravnborg bzImage will decompress itself to above physical address and 2135506f1d07SSam Ravnborg run from there. Otherwise, bzImage will run from the address where 2136506f1d07SSam Ravnborg it has been loaded by the boot loader and will ignore above physical 2137506f1d07SSam Ravnborg address. 2138506f1d07SSam Ravnborg 2139506f1d07SSam Ravnborg In normal kdump cases one does not have to set/change this option 2140506f1d07SSam Ravnborg as now bzImage can be compiled as a completely relocatable image 2141506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2142506f1d07SSam Ravnborg address. This option is mainly useful for the folks who don't want 2143506f1d07SSam Ravnborg to use a bzImage for capturing the crash dump and want to use a 2144506f1d07SSam Ravnborg vmlinux instead. vmlinux is not relocatable hence a kernel needs 2145506f1d07SSam Ravnborg to be specifically compiled to run from a specific memory area 2146506f1d07SSam Ravnborg (normally a reserved region) and this option comes handy. 2147506f1d07SSam Ravnborg 2148ceefccc9SH. Peter Anvin So if you are using bzImage for capturing the crash dump, 2149ceefccc9SH. Peter Anvin leave the value here unchanged to 0x1000000 and set 2150ceefccc9SH. Peter Anvin CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2151ceefccc9SH. Peter Anvin for capturing the crash dump change this value to start of 2152ceefccc9SH. Peter Anvin the reserved region. In other words, it can be set based on 2153ceefccc9SH. Peter Anvin the "X" value as specified in the "crashkernel=YM@XM" 2154ceefccc9SH. Peter Anvin command line boot parameter passed to the panic-ed 2155330d4810SMauro Carvalho Chehab kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2156ceefccc9SH. Peter Anvin for more details about crash dumps. 2157506f1d07SSam Ravnborg 2158506f1d07SSam Ravnborg Usage of bzImage for capturing the crash dump is recommended as 2159506f1d07SSam Ravnborg one does not have to build two kernels. Same kernel can be used 2160506f1d07SSam Ravnborg as production kernel and capture kernel. Above option should have 2161506f1d07SSam Ravnborg gone away after relocatable bzImage support is introduced. But it 2162506f1d07SSam Ravnborg is present because there are users out there who continue to use 2163506f1d07SSam Ravnborg vmlinux for dump capture. This option should go away down the 2164506f1d07SSam Ravnborg line. 2165506f1d07SSam Ravnborg 2166506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2167506f1d07SSam Ravnborg 2168506f1d07SSam Ravnborgconfig RELOCATABLE 216926717808SH. Peter Anvin bool "Build a relocatable kernel" 217026717808SH. Peter Anvin default y 2171a7f7f624SMasahiro Yamada help 2172506f1d07SSam Ravnborg This builds a kernel image that retains relocation information 2173506f1d07SSam Ravnborg so it can be loaded someplace besides the default 1MB. 2174506f1d07SSam Ravnborg The relocations tend to make the kernel binary about 10% larger, 2175506f1d07SSam Ravnborg but are discarded at runtime. 2176506f1d07SSam Ravnborg 2177506f1d07SSam Ravnborg One use is for the kexec on panic case where the recovery kernel 2178506f1d07SSam Ravnborg must live at a different physical address than the primary 2179506f1d07SSam Ravnborg kernel. 2180506f1d07SSam Ravnborg 2181506f1d07SSam Ravnborg Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2182506f1d07SSam Ravnborg it has been loaded at and the compile time physical address 21838ab3820fSKees Cook (CONFIG_PHYSICAL_START) is used as the minimum location. 2184506f1d07SSam Ravnborg 21858ab3820fSKees Cookconfig RANDOMIZE_BASE 2186e8581e3dSBaoquan He bool "Randomize the address of the kernel image (KASLR)" 21878ab3820fSKees Cook depends on RELOCATABLE 21886807c846SIngo Molnar default y 2189a7f7f624SMasahiro Yamada help 2190e8581e3dSBaoquan He In support of Kernel Address Space Layout Randomization (KASLR), 2191e8581e3dSBaoquan He this randomizes the physical address at which the kernel image 2192e8581e3dSBaoquan He is decompressed and the virtual address where the kernel 2193e8581e3dSBaoquan He image is mapped, as a security feature that deters exploit 2194e8581e3dSBaoquan He attempts relying on knowledge of the location of kernel 2195e8581e3dSBaoquan He code internals. 2196e8581e3dSBaoquan He 2197ed9f007eSKees Cook On 64-bit, the kernel physical and virtual addresses are 2198ed9f007eSKees Cook randomized separately. The physical address will be anywhere 2199ed9f007eSKees Cook between 16MB and the top of physical memory (up to 64TB). The 2200ed9f007eSKees Cook virtual address will be randomized from 16MB up to 1GB (9 bits 2201ed9f007eSKees Cook of entropy). Note that this also reduces the memory space 2202ed9f007eSKees Cook available to kernel modules from 1.5GB to 1GB. 2203ed9f007eSKees Cook 2204ed9f007eSKees Cook On 32-bit, the kernel physical and virtual addresses are 2205ed9f007eSKees Cook randomized together. They will be randomized from 16MB up to 2206ed9f007eSKees Cook 512MB (8 bits of entropy). 22078ab3820fSKees Cook 2208a653f356SKees Cook Entropy is generated using the RDRAND instruction if it is 2209e8581e3dSBaoquan He supported. If RDTSC is supported, its value is mixed into 2210e8581e3dSBaoquan He the entropy pool as well. If neither RDRAND nor RDTSC are 2211ed9f007eSKees Cook supported, then entropy is read from the i8254 timer. The 2212ed9f007eSKees Cook usable entropy is limited by the kernel being built using 2213ed9f007eSKees Cook 2GB addressing, and that PHYSICAL_ALIGN must be at a 2214ed9f007eSKees Cook minimum of 2MB. As a result, only 10 bits of entropy are 2215ed9f007eSKees Cook theoretically possible, but the implementations are further 2216ed9f007eSKees Cook limited due to memory layouts. 2217e8581e3dSBaoquan He 22186807c846SIngo Molnar If unsure, say Y. 2219da2b6fb9SKees Cook 22208ab3820fSKees Cook# Relocation on x86 needs some additional build support 2221845adf72SH. Peter Anvinconfig X86_NEED_RELOCS 2222845adf72SH. Peter Anvin def_bool y 22238ab3820fSKees Cook depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2224845adf72SH. Peter Anvin 2225506f1d07SSam Ravnborgconfig PHYSICAL_ALIGN 2226a0215061SKees Cook hex "Alignment value to which kernel should be aligned" 22278ab3820fSKees Cook default "0x200000" 2228a0215061SKees Cook range 0x2000 0x1000000 if X86_32 2229a0215061SKees Cook range 0x200000 0x1000000 if X86_64 2230a7f7f624SMasahiro Yamada help 2231506f1d07SSam Ravnborg This value puts the alignment restrictions on physical address 2232506f1d07SSam Ravnborg where kernel is loaded and run from. Kernel is compiled for an 2233506f1d07SSam Ravnborg address which meets above alignment restriction. 2234506f1d07SSam Ravnborg 2235506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2236506f1d07SSam Ravnborg CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2237506f1d07SSam Ravnborg address aligned to above value and run from there. 2238506f1d07SSam Ravnborg 2239506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2240506f1d07SSam Ravnborg CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2241506f1d07SSam Ravnborg load address and decompress itself to the address it has been 2242506f1d07SSam Ravnborg compiled for and run from there. The address for which kernel is 2243506f1d07SSam Ravnborg compiled already meets above alignment restrictions. Hence the 2244506f1d07SSam Ravnborg end result is that kernel runs from a physical address meeting 2245506f1d07SSam Ravnborg above alignment restrictions. 2246506f1d07SSam Ravnborg 2247a0215061SKees Cook On 32-bit this value must be a multiple of 0x2000. On 64-bit 2248a0215061SKees Cook this value must be a multiple of 0x200000. 2249a0215061SKees Cook 2250506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2251506f1d07SSam Ravnborg 2252eedb92abSKirill A. Shutemovconfig DYNAMIC_MEMORY_LAYOUT 2253eedb92abSKirill A. Shutemov bool 2254a7f7f624SMasahiro Yamada help 2255eedb92abSKirill A. Shutemov This option makes base addresses of vmalloc and vmemmap as well as 2256eedb92abSKirill A. Shutemov __PAGE_OFFSET movable during boot. 2257eedb92abSKirill A. Shutemov 22580483e1faSThomas Garnierconfig RANDOMIZE_MEMORY 22590483e1faSThomas Garnier bool "Randomize the kernel memory sections" 22600483e1faSThomas Garnier depends on X86_64 22610483e1faSThomas Garnier depends on RANDOMIZE_BASE 2262eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 22630483e1faSThomas Garnier default RANDOMIZE_BASE 2264a7f7f624SMasahiro Yamada help 22650483e1faSThomas Garnier Randomizes the base virtual address of kernel memory sections 22660483e1faSThomas Garnier (physical memory mapping, vmalloc & vmemmap). This security feature 22670483e1faSThomas Garnier makes exploits relying on predictable memory locations less reliable. 22680483e1faSThomas Garnier 22690483e1faSThomas Garnier The order of allocations remains unchanged. Entropy is generated in 22700483e1faSThomas Garnier the same way as RANDOMIZE_BASE. Current implementation in the optimal 22710483e1faSThomas Garnier configuration have in average 30,000 different possible virtual 22720483e1faSThomas Garnier addresses for each memory section. 22730483e1faSThomas Garnier 22746807c846SIngo Molnar If unsure, say Y. 22750483e1faSThomas Garnier 227690397a41SThomas Garnierconfig RANDOMIZE_MEMORY_PHYSICAL_PADDING 227790397a41SThomas Garnier hex "Physical memory mapping padding" if EXPERT 227890397a41SThomas Garnier depends on RANDOMIZE_MEMORY 227990397a41SThomas Garnier default "0xa" if MEMORY_HOTPLUG 228090397a41SThomas Garnier default "0x0" 228190397a41SThomas Garnier range 0x1 0x40 if MEMORY_HOTPLUG 228290397a41SThomas Garnier range 0x0 0x40 2283a7f7f624SMasahiro Yamada help 228490397a41SThomas Garnier Define the padding in terabytes added to the existing physical 228590397a41SThomas Garnier memory size during kernel memory randomization. It is useful 228690397a41SThomas Garnier for memory hotplug support but reduces the entropy available for 228790397a41SThomas Garnier address randomization. 228890397a41SThomas Garnier 228990397a41SThomas Garnier If unsure, leave at the default value. 229090397a41SThomas Garnier 22916449dcb0SKirill A. Shutemovconfig ADDRESS_MASKING 22926449dcb0SKirill A. Shutemov bool "Linear Address Masking support" 22936449dcb0SKirill A. Shutemov depends on X86_64 22946449dcb0SKirill A. Shutemov help 22956449dcb0SKirill A. Shutemov Linear Address Masking (LAM) modifies the checking that is applied 22966449dcb0SKirill A. Shutemov to 64-bit linear addresses, allowing software to use of the 22976449dcb0SKirill A. Shutemov untranslated address bits for metadata. 22986449dcb0SKirill A. Shutemov 22996449dcb0SKirill A. Shutemov The capability can be used for efficient address sanitizers (ASAN) 23006449dcb0SKirill A. Shutemov implementation and for optimizations in JITs. 23016449dcb0SKirill A. Shutemov 2302506f1d07SSam Ravnborgconfig HOTPLUG_CPU 2303bebd024eSThomas Gleixner def_bool y 230440b31360SStephen Rothwell depends on SMP 2305506f1d07SSam Ravnborg 2306506f1d07SSam Ravnborgconfig COMPAT_VDSO 2307b0b49f26SAndy Lutomirski def_bool n 2308b0b49f26SAndy Lutomirski prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2309953fee1dSIngo Molnar depends on COMPAT_32 2310a7f7f624SMasahiro Yamada help 2311b0b49f26SAndy Lutomirski Certain buggy versions of glibc will crash if they are 2312b0b49f26SAndy Lutomirski presented with a 32-bit vDSO that is not mapped at the address 2313b0b49f26SAndy Lutomirski indicated in its segment table. 2314e84446deSRandy Dunlap 2315b0b49f26SAndy Lutomirski The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2316b0b49f26SAndy Lutomirski and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2317b0b49f26SAndy Lutomirski 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2318b0b49f26SAndy Lutomirski the only released version with the bug, but OpenSUSE 9 2319b0b49f26SAndy Lutomirski contains a buggy "glibc 2.3.2". 2320506f1d07SSam Ravnborg 2321b0b49f26SAndy Lutomirski The symptom of the bug is that everything crashes on startup, saying: 2322b0b49f26SAndy Lutomirski dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2323b0b49f26SAndy Lutomirski 2324b0b49f26SAndy Lutomirski Saying Y here changes the default value of the vdso32 boot 2325b0b49f26SAndy Lutomirski option from 1 to 0, which turns off the 32-bit vDSO entirely. 2326b0b49f26SAndy Lutomirski This works around the glibc bug but hurts performance. 2327b0b49f26SAndy Lutomirski 2328b0b49f26SAndy Lutomirski If unsure, say N: if you are compiling your own kernel, you 2329b0b49f26SAndy Lutomirski are unlikely to be using a buggy version of glibc. 2330506f1d07SSam Ravnborg 23313dc33bd3SKees Cookchoice 23323dc33bd3SKees Cook prompt "vsyscall table for legacy applications" 23333dc33bd3SKees Cook depends on X86_64 2334625b7b7fSAndy Lutomirski default LEGACY_VSYSCALL_XONLY 23353dc33bd3SKees Cook help 23363dc33bd3SKees Cook Legacy user code that does not know how to find the vDSO expects 23373dc33bd3SKees Cook to be able to issue three syscalls by calling fixed addresses in 23383dc33bd3SKees Cook kernel space. Since this location is not randomized with ASLR, 23393dc33bd3SKees Cook it can be used to assist security vulnerability exploitation. 23403dc33bd3SKees Cook 23413dc33bd3SKees Cook This setting can be changed at boot time via the kernel command 2342bf00745eSAndy Lutomirski line parameter vsyscall=[emulate|xonly|none]. Emulate mode 2343bf00745eSAndy Lutomirski is deprecated and can only be enabled using the kernel command 2344bf00745eSAndy Lutomirski line. 23453dc33bd3SKees Cook 23463dc33bd3SKees Cook On a system with recent enough glibc (2.14 or newer) and no 23473dc33bd3SKees Cook static binaries, you can say None without a performance penalty 23483dc33bd3SKees Cook to improve security. 23493dc33bd3SKees Cook 2350bd49e16eSAndy Lutomirski If unsure, select "Emulate execution only". 23513dc33bd3SKees Cook 2352bd49e16eSAndy Lutomirski config LEGACY_VSYSCALL_XONLY 2353bd49e16eSAndy Lutomirski bool "Emulate execution only" 2354bd49e16eSAndy Lutomirski help 2355bd49e16eSAndy Lutomirski The kernel traps and emulates calls into the fixed vsyscall 2356bd49e16eSAndy Lutomirski address mapping and does not allow reads. This 2357bd49e16eSAndy Lutomirski configuration is recommended when userspace might use the 2358bd49e16eSAndy Lutomirski legacy vsyscall area but support for legacy binary 2359bd49e16eSAndy Lutomirski instrumentation of legacy code is not needed. It mitigates 2360bd49e16eSAndy Lutomirski certain uses of the vsyscall area as an ASLR-bypassing 2361bd49e16eSAndy Lutomirski buffer. 23623dc33bd3SKees Cook 23633dc33bd3SKees Cook config LEGACY_VSYSCALL_NONE 23643dc33bd3SKees Cook bool "None" 23653dc33bd3SKees Cook help 23663dc33bd3SKees Cook There will be no vsyscall mapping at all. This will 23673dc33bd3SKees Cook eliminate any risk of ASLR bypass due to the vsyscall 23683dc33bd3SKees Cook fixed address mapping. Attempts to use the vsyscalls 23693dc33bd3SKees Cook will be reported to dmesg, so that either old or 23703dc33bd3SKees Cook malicious userspace programs can be identified. 23713dc33bd3SKees Cook 23723dc33bd3SKees Cookendchoice 23733dc33bd3SKees Cook 2374516cbf37STim Birdconfig CMDLINE_BOOL 2375516cbf37STim Bird bool "Built-in kernel command line" 2376a7f7f624SMasahiro Yamada help 2377516cbf37STim Bird Allow for specifying boot arguments to the kernel at 2378516cbf37STim Bird build time. On some systems (e.g. embedded ones), it is 2379516cbf37STim Bird necessary or convenient to provide some or all of the 2380516cbf37STim Bird kernel boot arguments with the kernel itself (that is, 2381516cbf37STim Bird to not rely on the boot loader to provide them.) 2382516cbf37STim Bird 2383516cbf37STim Bird To compile command line arguments into the kernel, 2384516cbf37STim Bird set this option to 'Y', then fill in the 238569711ca1SSébastien Hinderer boot arguments in CONFIG_CMDLINE. 2386516cbf37STim Bird 2387516cbf37STim Bird Systems with fully functional boot loaders (i.e. non-embedded) 2388516cbf37STim Bird should leave this option set to 'N'. 2389516cbf37STim Bird 2390516cbf37STim Birdconfig CMDLINE 2391516cbf37STim Bird string "Built-in kernel command string" 2392516cbf37STim Bird depends on CMDLINE_BOOL 2393516cbf37STim Bird default "" 2394a7f7f624SMasahiro Yamada help 2395516cbf37STim Bird Enter arguments here that should be compiled into the kernel 2396516cbf37STim Bird image and used at boot time. If the boot loader provides a 2397516cbf37STim Bird command line at boot time, it is appended to this string to 2398516cbf37STim Bird form the full kernel command line, when the system boots. 2399516cbf37STim Bird 2400516cbf37STim Bird However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2401516cbf37STim Bird change this behavior. 2402516cbf37STim Bird 2403516cbf37STim Bird In most cases, the command line (whether built-in or provided 2404516cbf37STim Bird by the boot loader) should specify the device for the root 2405516cbf37STim Bird file system. 2406516cbf37STim Bird 2407516cbf37STim Birdconfig CMDLINE_OVERRIDE 2408516cbf37STim Bird bool "Built-in command line overrides boot loader arguments" 2409645e6466SAnders Roxell depends on CMDLINE_BOOL && CMDLINE != "" 2410a7f7f624SMasahiro Yamada help 2411516cbf37STim Bird Set this option to 'Y' to have the kernel ignore the boot loader 2412516cbf37STim Bird command line, and use ONLY the built-in command line. 2413516cbf37STim Bird 2414516cbf37STim Bird This is used to work around broken boot loaders. This should 2415516cbf37STim Bird be set to 'N' under normal conditions. 2416516cbf37STim Bird 2417a5b9e5a2SAndy Lutomirskiconfig MODIFY_LDT_SYSCALL 2418a5b9e5a2SAndy Lutomirski bool "Enable the LDT (local descriptor table)" if EXPERT 2419a5b9e5a2SAndy Lutomirski default y 2420a7f7f624SMasahiro Yamada help 2421a5b9e5a2SAndy Lutomirski Linux can allow user programs to install a per-process x86 2422a5b9e5a2SAndy Lutomirski Local Descriptor Table (LDT) using the modify_ldt(2) system 2423a5b9e5a2SAndy Lutomirski call. This is required to run 16-bit or segmented code such as 2424a5b9e5a2SAndy Lutomirski DOSEMU or some Wine programs. It is also used by some very old 2425a5b9e5a2SAndy Lutomirski threading libraries. 2426a5b9e5a2SAndy Lutomirski 2427a5b9e5a2SAndy Lutomirski Enabling this feature adds a small amount of overhead to 2428a5b9e5a2SAndy Lutomirski context switches and increases the low-level kernel attack 2429a5b9e5a2SAndy Lutomirski surface. Disabling it removes the modify_ldt(2) system call. 2430a5b9e5a2SAndy Lutomirski 2431a5b9e5a2SAndy Lutomirski Saying 'N' here may make sense for embedded or server kernels. 2432a5b9e5a2SAndy Lutomirski 24333aac3ebeSThomas Gleixnerconfig STRICT_SIGALTSTACK_SIZE 24343aac3ebeSThomas Gleixner bool "Enforce strict size checking for sigaltstack" 24353aac3ebeSThomas Gleixner depends on DYNAMIC_SIGFRAME 24363aac3ebeSThomas Gleixner help 24373aac3ebeSThomas Gleixner For historical reasons MINSIGSTKSZ is a constant which became 24383aac3ebeSThomas Gleixner already too small with AVX512 support. Add a mechanism to 24393aac3ebeSThomas Gleixner enforce strict checking of the sigaltstack size against the 24403aac3ebeSThomas Gleixner real size of the FPU frame. This option enables the check 24413aac3ebeSThomas Gleixner by default. It can also be controlled via the kernel command 24423aac3ebeSThomas Gleixner line option 'strict_sas_size' independent of this config 24433aac3ebeSThomas Gleixner switch. Enabling it might break existing applications which 24443aac3ebeSThomas Gleixner allocate a too small sigaltstack but 'work' because they 24453aac3ebeSThomas Gleixner never get a signal delivered. 24463aac3ebeSThomas Gleixner 24473aac3ebeSThomas Gleixner Say 'N' unless you want to really enforce this check. 24483aac3ebeSThomas Gleixner 2449b700e7f0SSeth Jenningssource "kernel/livepatch/Kconfig" 2450b700e7f0SSeth Jennings 2451506f1d07SSam Ravnborgendmenu 2452506f1d07SSam Ravnborg 2453f43b9876SPeter Zijlstraconfig CC_HAS_SLS 2454f43b9876SPeter Zijlstra def_bool $(cc-option,-mharden-sls=all) 2455f43b9876SPeter Zijlstra 2456f43b9876SPeter Zijlstraconfig CC_HAS_RETURN_THUNK 2457f43b9876SPeter Zijlstra def_bool $(cc-option,-mfunction-return=thunk-extern) 2458f43b9876SPeter Zijlstra 2459bea75b33SThomas Gleixnerconfig CC_HAS_ENTRY_PADDING 2460bea75b33SThomas Gleixner def_bool $(cc-option,-fpatchable-function-entry=16,16) 2461bea75b33SThomas Gleixner 2462bea75b33SThomas Gleixnerconfig FUNCTION_PADDING_CFI 2463bea75b33SThomas Gleixner int 2464bea75b33SThomas Gleixner default 59 if FUNCTION_ALIGNMENT_64B 2465bea75b33SThomas Gleixner default 27 if FUNCTION_ALIGNMENT_32B 2466bea75b33SThomas Gleixner default 11 if FUNCTION_ALIGNMENT_16B 2467bea75b33SThomas Gleixner default 3 if FUNCTION_ALIGNMENT_8B 2468bea75b33SThomas Gleixner default 0 2469bea75b33SThomas Gleixner 2470bea75b33SThomas Gleixner# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG 2471bea75b33SThomas Gleixner# except Kconfig can't do arithmetic :/ 2472bea75b33SThomas Gleixnerconfig FUNCTION_PADDING_BYTES 2473bea75b33SThomas Gleixner int 2474bea75b33SThomas Gleixner default FUNCTION_PADDING_CFI if CFI_CLANG 2475bea75b33SThomas Gleixner default FUNCTION_ALIGNMENT 2476bea75b33SThomas Gleixner 2477931ab636SPeter Zijlstraconfig CALL_PADDING 2478931ab636SPeter Zijlstra def_bool n 2479931ab636SPeter Zijlstra depends on CC_HAS_ENTRY_PADDING && OBJTOOL 2480931ab636SPeter Zijlstra select FUNCTION_ALIGNMENT_16B 2481931ab636SPeter Zijlstra 2482931ab636SPeter Zijlstraconfig FINEIBT 2483931ab636SPeter Zijlstra def_bool y 2484931ab636SPeter Zijlstra depends on X86_KERNEL_IBT && CFI_CLANG && RETPOLINE 2485931ab636SPeter Zijlstra select CALL_PADDING 2486931ab636SPeter Zijlstra 24878f7c0d8bSThomas Gleixnerconfig HAVE_CALL_THUNKS 24888f7c0d8bSThomas Gleixner def_bool y 2489bea75b33SThomas Gleixner depends on CC_HAS_ENTRY_PADDING && RETHUNK && OBJTOOL 24908f7c0d8bSThomas Gleixner 24918f7c0d8bSThomas Gleixnerconfig CALL_THUNKS 24928f7c0d8bSThomas Gleixner def_bool n 2493931ab636SPeter Zijlstra select CALL_PADDING 24948f7c0d8bSThomas Gleixner 2495b341b20dSPeter Zijlstraconfig PREFIX_SYMBOLS 2496b341b20dSPeter Zijlstra def_bool y 2497931ab636SPeter Zijlstra depends on CALL_PADDING && !CFI_CLANG 2498b341b20dSPeter Zijlstra 2499f43b9876SPeter Zijlstramenuconfig SPECULATION_MITIGATIONS 2500f43b9876SPeter Zijlstra bool "Mitigations for speculative execution vulnerabilities" 2501f43b9876SPeter Zijlstra default y 2502f43b9876SPeter Zijlstra help 2503f43b9876SPeter Zijlstra Say Y here to enable options which enable mitigations for 2504f43b9876SPeter Zijlstra speculative execution hardware vulnerabilities. 2505f43b9876SPeter Zijlstra 2506f43b9876SPeter Zijlstra If you say N, all mitigations will be disabled. You really 2507f43b9876SPeter Zijlstra should know what you are doing to say so. 2508f43b9876SPeter Zijlstra 2509f43b9876SPeter Zijlstraif SPECULATION_MITIGATIONS 2510f43b9876SPeter Zijlstra 2511f43b9876SPeter Zijlstraconfig PAGE_TABLE_ISOLATION 2512f43b9876SPeter Zijlstra bool "Remove the kernel mapping in user mode" 2513f43b9876SPeter Zijlstra default y 2514f43b9876SPeter Zijlstra depends on (X86_64 || X86_PAE) 2515f43b9876SPeter Zijlstra help 2516f43b9876SPeter Zijlstra This feature reduces the number of hardware side channels by 2517f43b9876SPeter Zijlstra ensuring that the majority of kernel addresses are not mapped 2518f43b9876SPeter Zijlstra into userspace. 2519f43b9876SPeter Zijlstra 2520ff61f079SJonathan Corbet See Documentation/arch/x86/pti.rst for more details. 2521f43b9876SPeter Zijlstra 2522f43b9876SPeter Zijlstraconfig RETPOLINE 2523f43b9876SPeter Zijlstra bool "Avoid speculative indirect branches in kernel" 2524f43b9876SPeter Zijlstra select OBJTOOL if HAVE_OBJTOOL 2525f43b9876SPeter Zijlstra default y 2526f43b9876SPeter Zijlstra help 2527f43b9876SPeter Zijlstra Compile kernel with the retpoline compiler options to guard against 2528f43b9876SPeter Zijlstra kernel-to-user data leaks by avoiding speculative indirect 2529f43b9876SPeter Zijlstra branches. Requires a compiler with -mindirect-branch=thunk-extern 2530f43b9876SPeter Zijlstra support for full protection. The kernel may run slower. 2531f43b9876SPeter Zijlstra 2532f43b9876SPeter Zijlstraconfig RETHUNK 2533f43b9876SPeter Zijlstra bool "Enable return-thunks" 2534f43b9876SPeter Zijlstra depends on RETPOLINE && CC_HAS_RETURN_THUNK 2535f43b9876SPeter Zijlstra select OBJTOOL if HAVE_OBJTOOL 2536b648ab48SBen Hutchings default y if X86_64 2537f43b9876SPeter Zijlstra help 2538f43b9876SPeter Zijlstra Compile the kernel with the return-thunks compiler option to guard 2539f43b9876SPeter Zijlstra against kernel-to-user data leaks by avoiding return speculation. 2540f43b9876SPeter Zijlstra Requires a compiler with -mfunction-return=thunk-extern 2541f43b9876SPeter Zijlstra support for full protection. The kernel may run slower. 2542f43b9876SPeter Zijlstra 2543f43b9876SPeter Zijlstraconfig CPU_UNRET_ENTRY 2544f43b9876SPeter Zijlstra bool "Enable UNRET on kernel entry" 2545b648ab48SBen Hutchings depends on CPU_SUP_AMD && RETHUNK && X86_64 2546f43b9876SPeter Zijlstra default y 2547f43b9876SPeter Zijlstra help 2548f43b9876SPeter Zijlstra Compile the kernel with support for the retbleed=unret mitigation. 2549f43b9876SPeter Zijlstra 255080e4c1cdSThomas Gleixnerconfig CALL_DEPTH_TRACKING 255180e4c1cdSThomas Gleixner bool "Mitigate RSB underflow with call depth tracking" 255280e4c1cdSThomas Gleixner depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS 255380e4c1cdSThomas Gleixner select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 255480e4c1cdSThomas Gleixner select CALL_THUNKS 255580e4c1cdSThomas Gleixner default y 255680e4c1cdSThomas Gleixner help 255780e4c1cdSThomas Gleixner Compile the kernel with call depth tracking to mitigate the Intel 255880e4c1cdSThomas Gleixner SKL Return-Speculation-Buffer (RSB) underflow issue. The 255980e4c1cdSThomas Gleixner mitigation is off by default and needs to be enabled on the 256080e4c1cdSThomas Gleixner kernel command line via the retbleed=stuff option. For 256180e4c1cdSThomas Gleixner non-affected systems the overhead of this option is marginal as 256280e4c1cdSThomas Gleixner the call depth tracking is using run-time generated call thunks 256380e4c1cdSThomas Gleixner in a compiler generated padding area and call patching. This 256480e4c1cdSThomas Gleixner increases text size by ~5%. For non affected systems this space 256580e4c1cdSThomas Gleixner is unused. On affected SKL systems this results in a significant 256680e4c1cdSThomas Gleixner performance gain over the IBRS mitigation. 256780e4c1cdSThomas Gleixner 2568e81dc127SThomas Gleixnerconfig CALL_THUNKS_DEBUG 2569e81dc127SThomas Gleixner bool "Enable call thunks and call depth tracking debugging" 2570e81dc127SThomas Gleixner depends on CALL_DEPTH_TRACKING 2571e81dc127SThomas Gleixner select FUNCTION_ALIGNMENT_32B 2572e81dc127SThomas Gleixner default n 2573e81dc127SThomas Gleixner help 2574e81dc127SThomas Gleixner Enable call/ret counters for imbalance detection and build in 2575e81dc127SThomas Gleixner a noisy dmesg about callthunks generation and call patching for 2576e81dc127SThomas Gleixner trouble shooting. The debug prints need to be enabled on the 2577e81dc127SThomas Gleixner kernel command line with 'debug-callthunks'. 257854628de6SRandy Dunlap Only enable this when you are debugging call thunks as this 257954628de6SRandy Dunlap creates a noticeable runtime overhead. If unsure say N. 258080e4c1cdSThomas Gleixner 2581f43b9876SPeter Zijlstraconfig CPU_IBPB_ENTRY 2582f43b9876SPeter Zijlstra bool "Enable IBPB on kernel entry" 2583b648ab48SBen Hutchings depends on CPU_SUP_AMD && X86_64 2584f43b9876SPeter Zijlstra default y 2585f43b9876SPeter Zijlstra help 2586f43b9876SPeter Zijlstra Compile the kernel with support for the retbleed=ibpb mitigation. 2587f43b9876SPeter Zijlstra 2588f43b9876SPeter Zijlstraconfig CPU_IBRS_ENTRY 2589f43b9876SPeter Zijlstra bool "Enable IBRS on kernel entry" 2590b648ab48SBen Hutchings depends on CPU_SUP_INTEL && X86_64 2591f43b9876SPeter Zijlstra default y 2592f43b9876SPeter Zijlstra help 2593f43b9876SPeter Zijlstra Compile the kernel with support for the spectre_v2=ibrs mitigation. 2594f43b9876SPeter Zijlstra This mitigates both spectre_v2 and retbleed at great cost to 2595f43b9876SPeter Zijlstra performance. 2596f43b9876SPeter Zijlstra 2597f43b9876SPeter Zijlstraconfig SLS 2598f43b9876SPeter Zijlstra bool "Mitigate Straight-Line-Speculation" 2599f43b9876SPeter Zijlstra depends on CC_HAS_SLS && X86_64 2600f43b9876SPeter Zijlstra select OBJTOOL if HAVE_OBJTOOL 2601f43b9876SPeter Zijlstra default n 2602f43b9876SPeter Zijlstra help 2603f43b9876SPeter Zijlstra Compile the kernel with straight-line-speculation options to guard 2604f43b9876SPeter Zijlstra against straight line speculation. The kernel image might be slightly 2605f43b9876SPeter Zijlstra larger. 2606f43b9876SPeter Zijlstra 2607f43b9876SPeter Zijlstraendif 2608f43b9876SPeter Zijlstra 26093072e413SMichal Hockoconfig ARCH_HAS_ADD_PAGES 26103072e413SMichal Hocko def_bool y 26115c11f00bSDavid Hildenbrand depends on ARCH_ENABLE_MEMORY_HOTPLUG 26123072e413SMichal Hocko 2613f91ef222SOscar Salvadorconfig ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 2614f91ef222SOscar Salvador def_bool y 2615f91ef222SOscar Salvador 2616da85f865SBjorn Helgaasmenu "Power management and ACPI options" 2617e279b6c1SSam Ravnborg 2618e279b6c1SSam Ravnborgconfig ARCH_HIBERNATION_HEADER 26193c2362e6SHarvey Harrison def_bool y 262044556530SZhimin Gu depends on HIBERNATION 2621e279b6c1SSam Ravnborg 2622e279b6c1SSam Ravnborgsource "kernel/power/Kconfig" 2623e279b6c1SSam Ravnborg 2624e279b6c1SSam Ravnborgsource "drivers/acpi/Kconfig" 2625e279b6c1SSam Ravnborg 2626a6b68076SAndi Kleenconfig X86_APM_BOOT 26276fc108a0SJan Beulich def_bool y 2628282e5aabSPaul Bolle depends on APM 2629a6b68076SAndi Kleen 2630e279b6c1SSam Ravnborgmenuconfig APM 2631e279b6c1SSam Ravnborg tristate "APM (Advanced Power Management) BIOS support" 2632efefa6f6SIngo Molnar depends on X86_32 && PM_SLEEP 2633a7f7f624SMasahiro Yamada help 2634e279b6c1SSam Ravnborg APM is a BIOS specification for saving power using several different 2635e279b6c1SSam Ravnborg techniques. This is mostly useful for battery powered laptops with 2636e279b6c1SSam Ravnborg APM compliant BIOSes. If you say Y here, the system time will be 2637e279b6c1SSam Ravnborg reset after a RESUME operation, the /proc/apm device will provide 2638e279b6c1SSam Ravnborg battery status information, and user-space programs will receive 2639e279b6c1SSam Ravnborg notification of APM "events" (e.g. battery status change). 2640e279b6c1SSam Ravnborg 2641e279b6c1SSam Ravnborg If you select "Y" here, you can disable actual use of the APM 2642e279b6c1SSam Ravnborg BIOS by passing the "apm=off" option to the kernel at boot time. 2643e279b6c1SSam Ravnborg 2644e279b6c1SSam Ravnborg Note that the APM support is almost completely disabled for 2645e279b6c1SSam Ravnborg machines with more than one CPU. 2646e279b6c1SSam Ravnborg 2647e279b6c1SSam Ravnborg In order to use APM, you will need supporting software. For location 2648151f4e2bSMauro Carvalho Chehab and more information, read <file:Documentation/power/apm-acpi.rst> 26492dc98fd3SMichael Witten and the Battery Powered Linux mini-HOWTO, available from 2650e279b6c1SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 2651e279b6c1SSam Ravnborg 2652e279b6c1SSam Ravnborg This driver does not spin down disk drives (see the hdparm(8) 2653e279b6c1SSam Ravnborg manpage ("man 8 hdparm") for that), and it doesn't turn off 2654e279b6c1SSam Ravnborg VESA-compliant "green" monitors. 2655e279b6c1SSam Ravnborg 2656e279b6c1SSam Ravnborg This driver does not support the TI 4000M TravelMate and the ACER 2657e279b6c1SSam Ravnborg 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2658e279b6c1SSam Ravnborg desktop machines also don't have compliant BIOSes, and this driver 2659e279b6c1SSam Ravnborg may cause those machines to panic during the boot phase. 2660e279b6c1SSam Ravnborg 2661e279b6c1SSam Ravnborg Generally, if you don't have a battery in your machine, there isn't 2662e279b6c1SSam Ravnborg much point in using this driver and you should say N. If you get 2663e279b6c1SSam Ravnborg random kernel OOPSes or reboots that don't seem to be related to 2664e279b6c1SSam Ravnborg anything, try disabling/enabling this option (or disabling/enabling 2665e279b6c1SSam Ravnborg APM in your BIOS). 2666e279b6c1SSam Ravnborg 2667e279b6c1SSam Ravnborg Some other things you should try when experiencing seemingly random, 2668e279b6c1SSam Ravnborg "weird" problems: 2669e279b6c1SSam Ravnborg 2670e279b6c1SSam Ravnborg 1) make sure that you have enough swap space and that it is 2671e279b6c1SSam Ravnborg enabled. 26727987448fSStephen Kitt 2) pass the "idle=poll" option to the kernel 2673e279b6c1SSam Ravnborg 3) switch on floating point emulation in the kernel and pass 2674e279b6c1SSam Ravnborg the "no387" option to the kernel 2675e279b6c1SSam Ravnborg 4) pass the "floppy=nodma" option to the kernel 2676e279b6c1SSam Ravnborg 5) pass the "mem=4M" option to the kernel (thereby disabling 2677e279b6c1SSam Ravnborg all but the first 4 MB of RAM) 2678e279b6c1SSam Ravnborg 6) make sure that the CPU is not over clocked. 2679e279b6c1SSam Ravnborg 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2680e279b6c1SSam Ravnborg 8) disable the cache from your BIOS settings 2681e279b6c1SSam Ravnborg 9) install a fan for the video card or exchange video RAM 2682e279b6c1SSam Ravnborg 10) install a better fan for the CPU 2683e279b6c1SSam Ravnborg 11) exchange RAM chips 2684e279b6c1SSam Ravnborg 12) exchange the motherboard. 2685e279b6c1SSam Ravnborg 2686e279b6c1SSam Ravnborg To compile this driver as a module, choose M here: the 2687e279b6c1SSam Ravnborg module will be called apm. 2688e279b6c1SSam Ravnborg 2689e279b6c1SSam Ravnborgif APM 2690e279b6c1SSam Ravnborg 2691e279b6c1SSam Ravnborgconfig APM_IGNORE_USER_SUSPEND 2692e279b6c1SSam Ravnborg bool "Ignore USER SUSPEND" 2693a7f7f624SMasahiro Yamada help 2694e279b6c1SSam Ravnborg This option will ignore USER SUSPEND requests. On machines with a 2695e279b6c1SSam Ravnborg compliant APM BIOS, you want to say N. However, on the NEC Versa M 2696e279b6c1SSam Ravnborg series notebooks, it is necessary to say Y because of a BIOS bug. 2697e279b6c1SSam Ravnborg 2698e279b6c1SSam Ravnborgconfig APM_DO_ENABLE 2699e279b6c1SSam Ravnborg bool "Enable PM at boot time" 2700a7f7f624SMasahiro Yamada help 2701e279b6c1SSam Ravnborg Enable APM features at boot time. From page 36 of the APM BIOS 2702e279b6c1SSam Ravnborg specification: "When disabled, the APM BIOS does not automatically 2703e279b6c1SSam Ravnborg power manage devices, enter the Standby State, enter the Suspend 2704e279b6c1SSam Ravnborg State, or take power saving steps in response to CPU Idle calls." 2705e279b6c1SSam Ravnborg This driver will make CPU Idle calls when Linux is idle (unless this 2706e279b6c1SSam Ravnborg feature is turned off -- see "Do CPU IDLE calls", below). This 2707e279b6c1SSam Ravnborg should always save battery power, but more complicated APM features 2708e279b6c1SSam Ravnborg will be dependent on your BIOS implementation. You may need to turn 2709e279b6c1SSam Ravnborg this option off if your computer hangs at boot time when using APM 2710e279b6c1SSam Ravnborg support, or if it beeps continuously instead of suspending. Turn 2711e279b6c1SSam Ravnborg this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2712e279b6c1SSam Ravnborg T400CDT. This is off by default since most machines do fine without 2713e279b6c1SSam Ravnborg this feature. 2714e279b6c1SSam Ravnborg 2715e279b6c1SSam Ravnborgconfig APM_CPU_IDLE 2716dd8af076SLen Brown depends on CPU_IDLE 2717e279b6c1SSam Ravnborg bool "Make CPU Idle calls when idle" 2718a7f7f624SMasahiro Yamada help 2719e279b6c1SSam Ravnborg Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2720e279b6c1SSam Ravnborg On some machines, this can activate improved power savings, such as 2721e279b6c1SSam Ravnborg a slowed CPU clock rate, when the machine is idle. These idle calls 2722e279b6c1SSam Ravnborg are made after the idle loop has run for some length of time (e.g., 2723e279b6c1SSam Ravnborg 333 mS). On some machines, this will cause a hang at boot time or 2724e279b6c1SSam Ravnborg whenever the CPU becomes idle. (On machines with more than one CPU, 2725e279b6c1SSam Ravnborg this option does nothing.) 2726e279b6c1SSam Ravnborg 2727e279b6c1SSam Ravnborgconfig APM_DISPLAY_BLANK 2728e279b6c1SSam Ravnborg bool "Enable console blanking using APM" 2729a7f7f624SMasahiro Yamada help 2730e279b6c1SSam Ravnborg Enable console blanking using the APM. Some laptops can use this to 2731e279b6c1SSam Ravnborg turn off the LCD backlight when the screen blanker of the Linux 2732e279b6c1SSam Ravnborg virtual console blanks the screen. Note that this is only used by 2733e279b6c1SSam Ravnborg the virtual console screen blanker, and won't turn off the backlight 2734e279b6c1SSam Ravnborg when using the X Window system. This also doesn't have anything to 2735e279b6c1SSam Ravnborg do with your VESA-compliant power-saving monitor. Further, this 2736e279b6c1SSam Ravnborg option doesn't work for all laptops -- it might not turn off your 2737e279b6c1SSam Ravnborg backlight at all, or it might print a lot of errors to the console, 2738e279b6c1SSam Ravnborg especially if you are using gpm. 2739e279b6c1SSam Ravnborg 2740e279b6c1SSam Ravnborgconfig APM_ALLOW_INTS 2741e279b6c1SSam Ravnborg bool "Allow interrupts during APM BIOS calls" 2742a7f7f624SMasahiro Yamada help 2743e279b6c1SSam Ravnborg Normally we disable external interrupts while we are making calls to 2744e279b6c1SSam Ravnborg the APM BIOS as a measure to lessen the effects of a badly behaving 2745e279b6c1SSam Ravnborg BIOS implementation. The BIOS should reenable interrupts if it 2746e279b6c1SSam Ravnborg needs to. Unfortunately, some BIOSes do not -- especially those in 2747e279b6c1SSam Ravnborg many of the newer IBM Thinkpads. If you experience hangs when you 2748e279b6c1SSam Ravnborg suspend, try setting this to Y. Otherwise, say N. 2749e279b6c1SSam Ravnborg 2750e279b6c1SSam Ravnborgendif # APM 2751e279b6c1SSam Ravnborg 2752bb0a56ecSDave Jonessource "drivers/cpufreq/Kconfig" 2753e279b6c1SSam Ravnborg 2754e279b6c1SSam Ravnborgsource "drivers/cpuidle/Kconfig" 2755e279b6c1SSam Ravnborg 275627471fdbSAndy Henroidsource "drivers/idle/Kconfig" 275727471fdbSAndy Henroid 2758e279b6c1SSam Ravnborgendmenu 2759e279b6c1SSam Ravnborg 2760e279b6c1SSam Ravnborgmenu "Bus options (PCI etc.)" 2761e279b6c1SSam Ravnborg 2762e279b6c1SSam Ravnborgchoice 2763e279b6c1SSam Ravnborg prompt "PCI access mode" 2764efefa6f6SIngo Molnar depends on X86_32 && PCI 2765e279b6c1SSam Ravnborg default PCI_GOANY 2766a7f7f624SMasahiro Yamada help 2767e279b6c1SSam Ravnborg On PCI systems, the BIOS can be used to detect the PCI devices and 2768e279b6c1SSam Ravnborg determine their configuration. However, some old PCI motherboards 2769e279b6c1SSam Ravnborg have BIOS bugs and may crash if this is done. Also, some embedded 2770e279b6c1SSam Ravnborg PCI-based systems don't have any BIOS at all. Linux can also try to 2771e279b6c1SSam Ravnborg detect the PCI hardware directly without using the BIOS. 2772e279b6c1SSam Ravnborg 2773e279b6c1SSam Ravnborg With this option, you can specify how Linux should detect the 2774e279b6c1SSam Ravnborg PCI devices. If you choose "BIOS", the BIOS will be used, 2775e279b6c1SSam Ravnborg if you choose "Direct", the BIOS won't be used, and if you 2776e279b6c1SSam Ravnborg choose "MMConfig", then PCI Express MMCONFIG will be used. 2777e279b6c1SSam Ravnborg If you choose "Any", the kernel will try MMCONFIG, then the 2778e279b6c1SSam Ravnborg direct access method and falls back to the BIOS if that doesn't 2779e279b6c1SSam Ravnborg work. If unsure, go with the default, which is "Any". 2780e279b6c1SSam Ravnborg 2781e279b6c1SSam Ravnborgconfig PCI_GOBIOS 2782e279b6c1SSam Ravnborg bool "BIOS" 2783e279b6c1SSam Ravnborg 2784e279b6c1SSam Ravnborgconfig PCI_GOMMCONFIG 2785e279b6c1SSam Ravnborg bool "MMConfig" 2786e279b6c1SSam Ravnborg 2787e279b6c1SSam Ravnborgconfig PCI_GODIRECT 2788e279b6c1SSam Ravnborg bool "Direct" 2789e279b6c1SSam Ravnborg 27903ef0e1f8SAndres Salomonconfig PCI_GOOLPC 279176fb6570SDaniel Drake bool "OLPC XO-1" 27923ef0e1f8SAndres Salomon depends on OLPC 27933ef0e1f8SAndres Salomon 27942bdd1b03SAndres Salomonconfig PCI_GOANY 27952bdd1b03SAndres Salomon bool "Any" 27962bdd1b03SAndres Salomon 2797e279b6c1SSam Ravnborgendchoice 2798e279b6c1SSam Ravnborg 2799e279b6c1SSam Ravnborgconfig PCI_BIOS 28003c2362e6SHarvey Harrison def_bool y 2801efefa6f6SIngo Molnar depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2802e279b6c1SSam Ravnborg 2803e279b6c1SSam Ravnborg# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2804e279b6c1SSam Ravnborgconfig PCI_DIRECT 28053c2362e6SHarvey Harrison def_bool y 28060aba496fSShaohua Li depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2807e279b6c1SSam Ravnborg 2808e279b6c1SSam Ravnborgconfig PCI_MMCONFIG 2809b45c9f36SJan Kiszka bool "Support mmconfig PCI config space access" if X86_64 2810b45c9f36SJan Kiszka default y 28114590d98fSAndy Shevchenko depends on PCI && (ACPI || JAILHOUSE_GUEST) 2812b45c9f36SJan Kiszka depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2813e279b6c1SSam Ravnborg 28143ef0e1f8SAndres Salomonconfig PCI_OLPC 28152bdd1b03SAndres Salomon def_bool y 28162bdd1b03SAndres Salomon depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 28173ef0e1f8SAndres Salomon 2818b5401a96SAlex Nixonconfig PCI_XEN 2819b5401a96SAlex Nixon def_bool y 2820b5401a96SAlex Nixon depends on PCI && XEN 2821b5401a96SAlex Nixon 28228364e1f8SJan Kiszkaconfig MMCONF_FAM10H 28238364e1f8SJan Kiszka def_bool y 28248364e1f8SJan Kiszka depends on X86_64 && PCI_MMCONFIG && ACPI 2825e279b6c1SSam Ravnborg 28263f6ea84aSIra W. Snyderconfig PCI_CNB20LE_QUIRK 28276a108a14SDavid Rientjes bool "Read CNB20LE Host Bridge Windows" if EXPERT 28286ea30386SKees Cook depends on PCI 28293f6ea84aSIra W. Snyder help 28303f6ea84aSIra W. Snyder Read the PCI windows out of the CNB20LE host bridge. This allows 28313f6ea84aSIra W. Snyder PCI hotplug to work on systems with the CNB20LE chipset which do 28323f6ea84aSIra W. Snyder not have ACPI. 28333f6ea84aSIra W. Snyder 283464a5fed6SBjorn Helgaas There's no public spec for this chipset, and this functionality 283564a5fed6SBjorn Helgaas is known to be incomplete. 283664a5fed6SBjorn Helgaas 283764a5fed6SBjorn Helgaas You should say N unless you know you need this. 283864a5fed6SBjorn Helgaas 28393a495511SWilliam Breathitt Grayconfig ISA_BUS 284017a2a129SWilliam Breathitt Gray bool "ISA bus support on modern systems" if EXPERT 28413a495511SWilliam Breathitt Gray help 284217a2a129SWilliam Breathitt Gray Expose ISA bus device drivers and options available for selection and 284317a2a129SWilliam Breathitt Gray configuration. Enable this option if your target machine has an ISA 284417a2a129SWilliam Breathitt Gray bus. ISA is an older system, displaced by PCI and newer bus 284517a2a129SWilliam Breathitt Gray architectures -- if your target machine is modern, it probably does 284617a2a129SWilliam Breathitt Gray not have an ISA bus. 28473a495511SWilliam Breathitt Gray 28483a495511SWilliam Breathitt Gray If unsure, say N. 28493a495511SWilliam Breathitt Gray 28501c00f016SDavid Rientjes# x86_64 have no ISA slots, but can have ISA-style DMA. 2851e279b6c1SSam Ravnborgconfig ISA_DMA_API 28521c00f016SDavid Rientjes bool "ISA-style DMA support" if (X86_64 && EXPERT) 28531c00f016SDavid Rientjes default y 28541c00f016SDavid Rientjes help 28551c00f016SDavid Rientjes Enables ISA-style DMA support for devices requiring such controllers. 28561c00f016SDavid Rientjes If unsure, say Y. 2857e279b6c1SSam Ravnborg 285851e68d05SLinus Torvaldsif X86_32 285951e68d05SLinus Torvalds 2860e279b6c1SSam Ravnborgconfig ISA 2861e279b6c1SSam Ravnborg bool "ISA support" 2862a7f7f624SMasahiro Yamada help 2863e279b6c1SSam Ravnborg Find out whether you have ISA slots on your motherboard. ISA is the 2864e279b6c1SSam Ravnborg name of a bus system, i.e. the way the CPU talks to the other stuff 2865e279b6c1SSam Ravnborg inside your box. Other bus systems are PCI, EISA, MicroChannel 2866e279b6c1SSam Ravnborg (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2867e279b6c1SSam Ravnborg newer boards don't support it. If you have ISA, say Y, otherwise N. 2868e279b6c1SSam Ravnborg 2869e279b6c1SSam Ravnborgconfig SCx200 2870e279b6c1SSam Ravnborg tristate "NatSemi SCx200 support" 2871a7f7f624SMasahiro Yamada help 2872e279b6c1SSam Ravnborg This provides basic support for National Semiconductor's 2873e279b6c1SSam Ravnborg (now AMD's) Geode processors. The driver probes for the 2874e279b6c1SSam Ravnborg PCI-IDs of several on-chip devices, so its a good dependency 2875e279b6c1SSam Ravnborg for other scx200_* drivers. 2876e279b6c1SSam Ravnborg 2877e279b6c1SSam Ravnborg If compiled as a module, the driver is named scx200. 2878e279b6c1SSam Ravnborg 2879e279b6c1SSam Ravnborgconfig SCx200HR_TIMER 2880e279b6c1SSam Ravnborg tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2881592913ecSJohn Stultz depends on SCx200 2882e279b6c1SSam Ravnborg default y 2883a7f7f624SMasahiro Yamada help 2884e279b6c1SSam Ravnborg This driver provides a clocksource built upon the on-chip 2885e279b6c1SSam Ravnborg 27MHz high-resolution timer. Its also a workaround for 2886e279b6c1SSam Ravnborg NSC Geode SC-1100's buggy TSC, which loses time when the 2887e279b6c1SSam Ravnborg processor goes idle (as is done by the scheduler). The 2888e279b6c1SSam Ravnborg other workaround is idle=poll boot option. 2889e279b6c1SSam Ravnborg 28903ef0e1f8SAndres Salomonconfig OLPC 28913ef0e1f8SAndres Salomon bool "One Laptop Per Child support" 289254008979SThomas Gleixner depends on !X86_PAE 28933c554946SAndres Salomon select GPIOLIB 2894dc3119e7SThomas Gleixner select OF 289545bb1674SDaniel Drake select OF_PROMTREE 2896b4e51854SGrant Likely select IRQ_DOMAIN 28970c3d931bSLubomir Rintel select OLPC_EC 2898a7f7f624SMasahiro Yamada help 28993ef0e1f8SAndres Salomon Add support for detecting the unique features of the OLPC 29003ef0e1f8SAndres Salomon XO hardware. 29013ef0e1f8SAndres Salomon 2902a3128588SDaniel Drakeconfig OLPC_XO1_PM 2903a3128588SDaniel Drake bool "OLPC XO-1 Power Management" 2904fa112cf1SBorislav Petkov depends on OLPC && MFD_CS5535=y && PM_SLEEP 2905a7f7f624SMasahiro Yamada help 290697c4cb71SDaniel Drake Add support for poweroff and suspend of the OLPC XO-1 laptop. 2907bf1ebf00SDaniel Drake 2908cfee9597SDaniel Drakeconfig OLPC_XO1_RTC 2909cfee9597SDaniel Drake bool "OLPC XO-1 Real Time Clock" 2910cfee9597SDaniel Drake depends on OLPC_XO1_PM && RTC_DRV_CMOS 2911a7f7f624SMasahiro Yamada help 2912cfee9597SDaniel Drake Add support for the XO-1 real time clock, which can be used as a 2913cfee9597SDaniel Drake programmable wakeup source. 2914cfee9597SDaniel Drake 29157feda8e9SDaniel Drakeconfig OLPC_XO1_SCI 29167feda8e9SDaniel Drake bool "OLPC XO-1 SCI extras" 291792e830f2SArnd Bergmann depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2918ed8e47feSRandy Dunlap depends on INPUT=y 2919d8d01a63SDaniel Drake select POWER_SUPPLY 2920a7f7f624SMasahiro Yamada help 29217feda8e9SDaniel Drake Add support for SCI-based features of the OLPC XO-1 laptop: 29227bc74b3dSDaniel Drake - EC-driven system wakeups 29237feda8e9SDaniel Drake - Power button 29247bc74b3dSDaniel Drake - Ebook switch 29252cf2baeaSDaniel Drake - Lid switch 2926e1040ac6SDaniel Drake - AC adapter status updates 2927e1040ac6SDaniel Drake - Battery status updates 29287feda8e9SDaniel Drake 2929a0f30f59SDaniel Drakeconfig OLPC_XO15_SCI 2930a0f30f59SDaniel Drake bool "OLPC XO-1.5 SCI extras" 2931d8d01a63SDaniel Drake depends on OLPC && ACPI 2932d8d01a63SDaniel Drake select POWER_SUPPLY 2933a7f7f624SMasahiro Yamada help 2934a0f30f59SDaniel Drake Add support for SCI-based features of the OLPC XO-1.5 laptop: 2935a0f30f59SDaniel Drake - EC-driven system wakeups 2936a0f30f59SDaniel Drake - AC adapter status updates 2937a0f30f59SDaniel Drake - Battery status updates 2938e279b6c1SSam Ravnborg 2939d4f3e350SEd Wildgooseconfig ALIX 2940d4f3e350SEd Wildgoose bool "PCEngines ALIX System Support (LED setup)" 2941d4f3e350SEd Wildgoose select GPIOLIB 2942a7f7f624SMasahiro Yamada help 2943d4f3e350SEd Wildgoose This option enables system support for the PCEngines ALIX. 2944d4f3e350SEd Wildgoose At present this just sets up LEDs for GPIO control on 2945d4f3e350SEd Wildgoose ALIX2/3/6 boards. However, other system specific setup should 2946d4f3e350SEd Wildgoose get added here. 2947d4f3e350SEd Wildgoose 2948d4f3e350SEd Wildgoose Note: You must still enable the drivers for GPIO and LED support 2949d4f3e350SEd Wildgoose (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2950d4f3e350SEd Wildgoose 2951d4f3e350SEd Wildgoose Note: You have to set alix.force=1 for boards with Award BIOS. 2952d4f3e350SEd Wildgoose 2953da4e3302SPhilip Prindevilleconfig NET5501 2954da4e3302SPhilip Prindeville bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2955da4e3302SPhilip Prindeville select GPIOLIB 2956a7f7f624SMasahiro Yamada help 2957da4e3302SPhilip Prindeville This option enables system support for the Soekris Engineering net5501. 2958da4e3302SPhilip Prindeville 29593197059aSPhilip A. Prindevilleconfig GEOS 29603197059aSPhilip A. Prindeville bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 29613197059aSPhilip A. Prindeville select GPIOLIB 29623197059aSPhilip A. Prindeville depends on DMI 2963a7f7f624SMasahiro Yamada help 29643197059aSPhilip A. Prindeville This option enables system support for the Traverse Technologies GEOS. 29653197059aSPhilip A. Prindeville 29667d029125SVivien Didelotconfig TS5500 29677d029125SVivien Didelot bool "Technologic Systems TS-5500 platform support" 29687d029125SVivien Didelot depends on MELAN 29697d029125SVivien Didelot select CHECK_SIGNATURE 29707d029125SVivien Didelot select NEW_LEDS 29717d029125SVivien Didelot select LEDS_CLASS 2972a7f7f624SMasahiro Yamada help 29737d029125SVivien Didelot This option enables system support for the Technologic Systems TS-5500. 29747d029125SVivien Didelot 2975e279b6c1SSam Ravnborgendif # X86_32 2976e279b6c1SSam Ravnborg 297723ac4ae8SAndreas Herrmannconfig AMD_NB 2978e279b6c1SSam Ravnborg def_bool y 29790e152cd7SBorislav Petkov depends on CPU_SUP_AMD && PCI 2980e279b6c1SSam Ravnborg 2981e279b6c1SSam Ravnborgendmenu 2982e279b6c1SSam Ravnborg 29831572497cSChristoph Hellwigmenu "Binary Emulations" 2984e279b6c1SSam Ravnborg 2985e279b6c1SSam Ravnborgconfig IA32_EMULATION 2986e279b6c1SSam Ravnborg bool "IA32 Emulation" 2987e279b6c1SSam Ravnborg depends on X86_64 298839f88911SIngo Molnar select ARCH_WANT_OLD_COMPAT_IPC 2989d1603990SRandy Dunlap select BINFMT_ELF 299039f88911SIngo Molnar select COMPAT_OLD_SIGACTION 2991a7f7f624SMasahiro Yamada help 29925fd92e65SH. J. Lu Include code to run legacy 32-bit programs under a 29935fd92e65SH. J. Lu 64-bit kernel. You should likely turn this on, unless you're 29945fd92e65SH. J. Lu 100% sure that you don't have any 32-bit programs left. 2995e279b6c1SSam Ravnborg 299683a44a4fSMasahiro Yamadaconfig X86_X32_ABI 29976ea30386SKees Cook bool "x32 ABI for 64-bit mode" 29989b54050bSBrian Gerst depends on X86_64 2999aaeed6ecSNathan Chancellor # llvm-objcopy does not convert x86_64 .note.gnu.property or 3000aaeed6ecSNathan Chancellor # compressed debug sections to x86_x32 properly: 3001aaeed6ecSNathan Chancellor # https://github.com/ClangBuiltLinux/linux/issues/514 3002aaeed6ecSNathan Chancellor # https://github.com/ClangBuiltLinux/linux/issues/1141 3003aaeed6ecSNathan Chancellor depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm) 3004a7f7f624SMasahiro Yamada help 30055fd92e65SH. J. Lu Include code to run binaries for the x32 native 32-bit ABI 30065fd92e65SH. J. Lu for 64-bit processors. An x32 process gets access to the 30075fd92e65SH. J. Lu full 64-bit register file and wide data path while leaving 30085fd92e65SH. J. Lu pointers at 32 bits for smaller memory footprint. 30095fd92e65SH. J. Lu 3010953fee1dSIngo Molnarconfig COMPAT_32 3011953fee1dSIngo Molnar def_bool y 3012953fee1dSIngo Molnar depends on IA32_EMULATION || X86_32 3013953fee1dSIngo Molnar select HAVE_UID16 3014953fee1dSIngo Molnar select OLD_SIGSUSPEND3 3015953fee1dSIngo Molnar 3016e279b6c1SSam Ravnborgconfig COMPAT 30173c2362e6SHarvey Harrison def_bool y 301883a44a4fSMasahiro Yamada depends on IA32_EMULATION || X86_X32_ABI 3019e279b6c1SSam Ravnborg 3020e279b6c1SSam Ravnborgconfig COMPAT_FOR_U64_ALIGNMENT 30213120e25eSJan Beulich def_bool y 3022a9251280SLinus Torvalds depends on COMPAT 3023ee009e4aSDavid Howells 3024e279b6c1SSam Ravnborgendmenu 3025e279b6c1SSam Ravnborg 3026e5beae16SKeith Packardconfig HAVE_ATOMIC_IOMAP 3027e5beae16SKeith Packard def_bool y 3028e5beae16SKeith Packard depends on X86_32 3029e5beae16SKeith Packard 3030edf88417SAvi Kivitysource "arch/x86/kvm/Kconfig" 30315e8ebd84SJason A. Donenfeld 30325e8ebd84SJason A. Donenfeldsource "arch/x86/Kconfig.assembler" 3033