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 1310b376f1eSAneesh Kumar K.V select ARCH_WANT_OPTIMIZE_VMEMMAP if X86_64 13238d8b4e6SHuang Ying select ARCH_WANTS_THP_SWAP if X86_64 133b5f06f64SBalbir Singh select ARCH_HAS_PARANOID_L1D_FLUSH 13410916706SShile Zhang select BUILDTIME_TABLE_SORT 1356471b825SIngo Molnar select CLKEVT_I8253 1366471b825SIngo Molnar select CLOCKSOURCE_VALIDATE_LAST_CYCLE 1376471b825SIngo Molnar select CLOCKSOURCE_WATCHDOG 1387cf8f44aSAlexander Potapenko # Word-size accesses may read uninitialized data past the trailing \0 1397cf8f44aSAlexander Potapenko # in strings and cause false KMSAN reports. 1407cf8f44aSAlexander Potapenko select DCACHE_WORD_ACCESS if !KMSAN 1413aac3ebeSThomas Gleixner select DYNAMIC_SIGFRAME 14245471cd9SLinus Torvalds select EDAC_ATOMIC_SCRUB 14345471cd9SLinus Torvalds select EDAC_SUPPORT 1446471b825SIngo Molnar select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 1456471b825SIngo Molnar select GENERIC_CLOCKEVENTS_MIN_ADJUST 1466471b825SIngo Molnar select GENERIC_CMOS_UPDATE 1476471b825SIngo Molnar select GENERIC_CPU_AUTOPROBE 14861dc0f55SThomas Gleixner select GENERIC_CPU_VULNERABILITIES 1496471b825SIngo Molnar select GENERIC_EARLY_IOREMAP 15027d6b4d1SThomas Gleixner select GENERIC_ENTRY 1516471b825SIngo Molnar select GENERIC_IOMAP 152c7d6c9ddSThomas Gleixner select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 1530fa115daSThomas Gleixner select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 154ad7a929fSThomas Gleixner select GENERIC_IRQ_MIGRATION if SMP 1556471b825SIngo Molnar select GENERIC_IRQ_PROBE 156c201c917SThomas Gleixner select GENERIC_IRQ_RESERVATION_MODE 1576471b825SIngo Molnar select GENERIC_IRQ_SHOW 1586471b825SIngo Molnar select GENERIC_PENDING_IRQ if SMP 1592ae27137SSteven Price select GENERIC_PTDUMP 1606471b825SIngo Molnar select GENERIC_SMP_IDLE_THREAD 1616471b825SIngo Molnar select GENERIC_TIME_VSYSCALL 1627ac87074SVincenzo Frascino select GENERIC_GETTIMEOFDAY 163550a77a7SDmitry Safonov select GENERIC_VDSO_TIME_NS 1646ca297d4SPeter Zijlstra select GUP_GET_PXX_LOW_HIGH if X86_PAE 16517e5888eSHans de Goede select HARDIRQS_SW_RESEND 1667edaeb68SThomas Gleixner select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 167fcbfe812SNiklas Schnelle select HAS_IOPORT 1686471b825SIngo Molnar select HAVE_ACPI_APEI if ACPI 1696471b825SIngo Molnar select HAVE_ACPI_APEI_NMI if ACPI 1706471b825SIngo Molnar select HAVE_ALIGNED_STRUCT_PAGE if SLUB 1716471b825SIngo Molnar select HAVE_ARCH_AUDITSYSCALL 1726471b825SIngo Molnar select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 173eed1fceeSSong Liu select HAVE_ARCH_HUGE_VMALLOC if X86_64 1746471b825SIngo Molnar select HAVE_ARCH_JUMP_LABEL 175b34006c4SArd Biesheuvel select HAVE_ARCH_JUMP_LABEL_RELATIVE 176d17a1d97SAndrey Ryabinin select HAVE_ARCH_KASAN if X86_64 1770609ae01SDaniel Axtens select HAVE_ARCH_KASAN_VMALLOC if X86_64 1781dc0da6eSAlexander Potapenko select HAVE_ARCH_KFENCE 1794ca8cc8dSAlexander Potapenko select HAVE_ARCH_KMSAN if X86_64 1806471b825SIngo Molnar select HAVE_ARCH_KGDB 1819e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_BITS if MMU 1829e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 1831b028f78SDmitry Safonov select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 184271ca788SArd Biesheuvel select HAVE_ARCH_PREL32_RELOCATIONS 1856471b825SIngo Molnar select HAVE_ARCH_SECCOMP_FILTER 186f7d83c1cSKees Cook select HAVE_ARCH_THREAD_STRUCT_WHITELIST 187afaef01cSAlexander Popov select HAVE_ARCH_STACKLEAK 1886471b825SIngo Molnar select HAVE_ARCH_TRACEHOOK 1896471b825SIngo Molnar select HAVE_ARCH_TRANSPARENT_HUGEPAGE 190a00cc7d9SMatthew Wilcox select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 191b64d8d1eSPeter Xu select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 1927677f7fdSAxel Rasmussen select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 193e37e43a4SAndy Lutomirski select HAVE_ARCH_VMAP_STACK if X86_64 194fe950f60SKees Cook select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 195c763ea26SIngo Molnar select HAVE_ARCH_WITHIN_STACK_FRAMES 1962ff2b7ecSMasahiro Yamada select HAVE_ASM_MODVERSIONS 1976471b825SIngo Molnar select HAVE_CMPXCHG_DOUBLE 1986471b825SIngo Molnar select HAVE_CMPXCHG_LOCAL 19924a9c541SFrederic Weisbecker select HAVE_CONTEXT_TRACKING_USER if X86_64 20024a9c541SFrederic Weisbecker select HAVE_CONTEXT_TRACKING_USER_OFFSTACK if HAVE_CONTEXT_TRACKING_USER 2016471b825SIngo Molnar select HAVE_C_RECORDMCOUNT 20203f16cd0SJosh Poimboeuf select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL 203280981d6SSathvika Vasireddy select HAVE_OBJTOOL_NOP_MCOUNT if HAVE_OBJTOOL_MCOUNT 2044ed308c4SSteven Rostedt (Google) select HAVE_BUILDTIME_MCOUNT_SORT 2056471b825SIngo Molnar select HAVE_DEBUG_KMEMLEAK 2069c5a3621SAkinobu Mita select HAVE_DMA_CONTIGUOUS 207677aa9f7SSteven Rostedt select HAVE_DYNAMIC_FTRACE 20806aeaaeaSMasami Hiramatsu select HAVE_DYNAMIC_FTRACE_WITH_REGS 20902a474caSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 210562955feSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 211c316eb44SHeiko Carstens select HAVE_SAMPLE_FTRACE_DIRECT if X86_64 212503e4510SHeiko Carstens select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64 21303f5781bSWang YanQing select HAVE_EBPF_JIT 21458340a07SJohannes Berg select HAVE_EFFICIENT_UNALIGNED_ACCESS 2156630a8e5SChristoph Hellwig select HAVE_EISA 2165f56a5dfSJiri Slaby select HAVE_EXIT_THREAD 21767a929e0SChristoph Hellwig select HAVE_FAST_GUP 218644e0e8dSSteven Rostedt (VMware) select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 2196471b825SIngo Molnar select HAVE_FTRACE_MCOUNT_RECORD 220d938ba17SDonglin Peng select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER 2214a30e4c9SSteven Rostedt (VMware) select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) 2226471b825SIngo Molnar select HAVE_FUNCTION_TRACER 2236b90bd4bSEmese Revfy select HAVE_GCC_PLUGINS 2240067f129SK.Prasad select HAVE_HW_BREAKPOINT 2256471b825SIngo Molnar select HAVE_IOREMAP_PROT 226624db9eaSThomas Gleixner select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 2276471b825SIngo Molnar select HAVE_IRQ_TIME_ACCOUNTING 2284ab7674fSJosh Poimboeuf select HAVE_JUMP_LABEL_HACK if HAVE_OBJTOOL 2296471b825SIngo Molnar select HAVE_KERNEL_BZIP2 2306471b825SIngo Molnar select HAVE_KERNEL_GZIP 2316471b825SIngo Molnar select HAVE_KERNEL_LZ4 2326471b825SIngo Molnar select HAVE_KERNEL_LZMA 2336471b825SIngo Molnar select HAVE_KERNEL_LZO 2346471b825SIngo Molnar select HAVE_KERNEL_XZ 235fb46d057SNick Terrell select HAVE_KERNEL_ZSTD 2366471b825SIngo Molnar select HAVE_KPROBES 2376471b825SIngo Molnar select HAVE_KPROBES_ON_FTRACE 238540adea3SMasami Hiramatsu select HAVE_FUNCTION_ERROR_INJECTION 2396471b825SIngo Molnar select HAVE_KRETPROBES 240f3a112c0SMasami Hiramatsu select HAVE_RETHOOK 2416471b825SIngo Molnar select HAVE_KVM 2426471b825SIngo Molnar select HAVE_LIVEPATCH if X86_64 2430102752eSFrederic Weisbecker select HAVE_MIXED_BREAKPOINTS_REGS 244ee9f8fceSJosh Poimboeuf select HAVE_MOD_ARCH_SPECIFIC 2459f132f7eSJoel Fernandes (Google) select HAVE_MOVE_PMD 246be37c98dSKalesh Singh select HAVE_MOVE_PUD 24722102f45SJosh Poimboeuf select HAVE_NOINSTR_HACK if HAVE_OBJTOOL 24842a0bb3fSPetr Mladek select HAVE_NMI 249489e355bSJosh Poimboeuf select HAVE_NOINSTR_VALIDATION if HAVE_OBJTOOL 25003f16cd0SJosh Poimboeuf select HAVE_OBJTOOL if X86_64 2516471b825SIngo Molnar select HAVE_OPTPROBES 2526471b825SIngo Molnar select HAVE_PCSPKR_PLATFORM 2536471b825SIngo Molnar select HAVE_PERF_EVENTS 254c01d4323SFrederic Weisbecker select HAVE_PERF_EVENTS_NMI 25592e5aae4SNicholas Piggin select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 256eb01d42aSChristoph Hellwig select HAVE_PCI 257c5e63197SJiri Olsa select HAVE_PERF_REGS 258c5ebcedbSJiri Olsa select HAVE_PERF_USER_STACK_DUMP 259ff2e6d72SPeter Zijlstra select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 2601e9fdf21SPeter Zijlstra select MMU_GATHER_MERGE_VMAS 26100998085SThomas Gleixner select HAVE_POSIX_CPU_TIMERS_TASK_WORK 2626471b825SIngo Molnar select HAVE_REGS_AND_STACK_ACCESS_API 26303f16cd0SJosh Poimboeuf select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC || STACK_VALIDATION 2643c88ee19SMasami Hiramatsu select HAVE_FUNCTION_ARG_ACCESS_API 2657ecd19cfSKefeng Wang select HAVE_SETUP_PER_CPU_AREA 266cd1a41ceSThomas Gleixner select HAVE_SOFTIRQ_ON_OWN_STACK 267d148eac0SMasahiro Yamada select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 26803f16cd0SJosh Poimboeuf select HAVE_STACK_VALIDATION if HAVE_OBJTOOL 269e6d6c071SJosh Poimboeuf select HAVE_STATIC_CALL 27003f16cd0SJosh Poimboeuf select HAVE_STATIC_CALL_INLINE if HAVE_OBJTOOL 27199cf983cSMark Rutland select HAVE_PREEMPT_DYNAMIC_CALL 272d6761b8fSMathieu Desnoyers select HAVE_RSEQ 27309498135SMiguel Ojeda select HAVE_RUST if X86_64 2746471b825SIngo Molnar select HAVE_SYSCALL_TRACEPOINTS 2755f3da8c0SJosh Poimboeuf select HAVE_UACCESS_VALIDATION if HAVE_OBJTOOL 2766471b825SIngo Molnar select HAVE_UNSTABLE_SCHED_CLOCK 2777c68af6eSAvi Kivity select HAVE_USER_RETURN_NOTIFIER 2787ac87074SVincenzo Frascino select HAVE_GENERIC_VDSO 2790c7ffa32SThomas Gleixner select HOTPLUG_PARALLEL if SMP && X86_64 28005736e4aSThomas Gleixner select HOTPLUG_SMT if SMP 2810c7ffa32SThomas Gleixner select HOTPLUG_SPLIT_STARTUP if SMP && X86_32 282c0185808SThomas Gleixner select IRQ_FORCED_THREADING 283c2508ec5SLinus Torvalds select LOCK_MM_AND_FIND_VMA 2847ecd19cfSKefeng Wang select NEED_PER_CPU_EMBED_FIRST_CHUNK 2857ecd19cfSKefeng Wang select NEED_PER_CPU_PAGE_FIRST_CHUNK 28686596f0aSChristoph Hellwig select NEED_SG_DMA_LENGTH 2872eac9c2dSChristoph Hellwig select PCI_DOMAINS if PCI 288625210cfSSinan Kaya select PCI_LOCKLESS_CONFIG if PCI 2896471b825SIngo Molnar select PERF_EVENTS 2903195ef59SPrarit Bhargava select RTC_LIB 291d6faca40SArnd Bergmann select RTC_MC146818_LIB 2926471b825SIngo Molnar select SPARSE_IRQ 2936471b825SIngo Molnar select SYSCTL_EXCEPTION_TRACE 29415f4eae7SAndy Lutomirski select THREAD_INFO_IN_TASK 2954aae683fSMasahiro Yamada select TRACE_IRQFLAGS_SUPPORT 2964510bffbSMark Rutland select TRACE_IRQFLAGS_NMI_SUPPORT 2976471b825SIngo Molnar select USER_STACKTRACE_SUPPORT 2983b02a051SIngo Molnar select HAVE_ARCH_KCSAN if X86_64 2990c608dadSAubrey Li select PROC_PID_ARCH_STATUS if PROC_FS 30050468e43SJarkko Sakkinen select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX 301d49a0626SPeter Zijlstra select FUNCTION_ALIGNMENT_16B if X86_64 || X86_ALIGNMENT_16 302d49a0626SPeter Zijlstra select FUNCTION_ALIGNMENT_4B 3039e2b4be3SNayna Jain imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 304ceea991aSJiri Olsa select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 3057d8330a5SBalbir Singh 306ba7e4d13SIngo Molnarconfig INSTRUCTION_DECODER 3073120e25eSJan Beulich def_bool y 3083120e25eSJan Beulich depends on KPROBES || PERF_EVENTS || UPROBES 309ba7e4d13SIngo Molnar 31051b26adaSLinus Torvaldsconfig OUTPUT_FORMAT 31151b26adaSLinus Torvalds string 31251b26adaSLinus Torvalds default "elf32-i386" if X86_32 31351b26adaSLinus Torvalds default "elf64-x86-64" if X86_64 31451b26adaSLinus Torvalds 3158d5fffb9SSam Ravnborgconfig LOCKDEP_SUPPORT 3163c2362e6SHarvey Harrison def_bool y 3178d5fffb9SSam Ravnborg 3188d5fffb9SSam Ravnborgconfig STACKTRACE_SUPPORT 3193c2362e6SHarvey Harrison def_bool y 3208d5fffb9SSam Ravnborg 3218d5fffb9SSam Ravnborgconfig MMU 3223c2362e6SHarvey Harrison def_bool y 3238d5fffb9SSam Ravnborg 3249e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MIN 3259e08f57dSDaniel Cashman default 28 if 64BIT 3269e08f57dSDaniel Cashman default 8 3279e08f57dSDaniel Cashman 3289e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MAX 3299e08f57dSDaniel Cashman default 32 if 64BIT 3309e08f57dSDaniel Cashman default 16 3319e08f57dSDaniel Cashman 3329e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MIN 3339e08f57dSDaniel Cashman default 8 3349e08f57dSDaniel Cashman 3359e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MAX 3369e08f57dSDaniel Cashman default 16 3379e08f57dSDaniel Cashman 3388d5fffb9SSam Ravnborgconfig SBUS 3398d5fffb9SSam Ravnborg bool 3408d5fffb9SSam Ravnborg 3418d5fffb9SSam Ravnborgconfig GENERIC_ISA_DMA 3423120e25eSJan Beulich def_bool y 3433120e25eSJan Beulich depends on ISA_DMA_API 3448d5fffb9SSam Ravnborg 345d911c67eSAlexander Potapenkoconfig GENERIC_CSUM 346d911c67eSAlexander Potapenko bool 347d911c67eSAlexander Potapenko default y if KMSAN || KASAN 348d911c67eSAlexander Potapenko 3498d5fffb9SSam Ravnborgconfig GENERIC_BUG 3503c2362e6SHarvey Harrison def_bool y 3518d5fffb9SSam Ravnborg depends on BUG 352b93a531eSJan Beulich select GENERIC_BUG_RELATIVE_POINTERS if X86_64 353b93a531eSJan Beulich 354b93a531eSJan Beulichconfig GENERIC_BUG_RELATIVE_POINTERS 355b93a531eSJan Beulich bool 3568d5fffb9SSam Ravnborg 3578d5fffb9SSam Ravnborgconfig ARCH_MAY_HAVE_PC_FDC 3583120e25eSJan Beulich def_bool y 3593120e25eSJan Beulich depends on ISA_DMA_API 3608d5fffb9SSam Ravnborg 3611032c0baSSam Ravnborgconfig GENERIC_CALIBRATE_DELAY 3621032c0baSSam Ravnborg def_bool y 3631032c0baSSam Ravnborg 3649a0b8415Svenkatesh.pallipadi@intel.comconfig ARCH_HAS_CPU_RELAX 3659a0b8415Svenkatesh.pallipadi@intel.com def_bool y 3668d5fffb9SSam Ravnborg 367801e4062SJohannes Bergconfig ARCH_HIBERNATION_POSSIBLE 368801e4062SJohannes Berg def_bool y 369801e4062SJohannes Berg 370f4cb5700SJohannes Bergconfig ARCH_SUSPEND_POSSIBLE 371f4cb5700SJohannes Berg def_bool y 372f4cb5700SJohannes Berg 3738d5fffb9SSam Ravnborgconfig AUDIT_ARCH 374e0fd24a3SJan Beulich def_bool y if X86_64 3758d5fffb9SSam Ravnborg 376d6f2d75aSAndrey Ryabininconfig KASAN_SHADOW_OFFSET 377d6f2d75aSAndrey Ryabinin hex 378d6f2d75aSAndrey Ryabinin depends on KASAN 379d6f2d75aSAndrey Ryabinin default 0xdffffc0000000000 380d6f2d75aSAndrey Ryabinin 38169575d38SShane Wangconfig HAVE_INTEL_TXT 38269575d38SShane Wang def_bool y 3836ea30386SKees Cook depends on INTEL_IOMMU && ACPI 38469575d38SShane Wang 3856b0c3d44SSam Ravnborgconfig X86_32_SMP 3866b0c3d44SSam Ravnborg def_bool y 3876b0c3d44SSam Ravnborg depends on X86_32 && SMP 3886b0c3d44SSam Ravnborg 3896b0c3d44SSam Ravnborgconfig X86_64_SMP 3906b0c3d44SSam Ravnborg def_bool y 3916b0c3d44SSam Ravnborg depends on X86_64 && SMP 3926b0c3d44SSam Ravnborg 3932b144498SSrikar Dronamrajuconfig ARCH_SUPPORTS_UPROBES 3942b144498SSrikar Dronamraju def_bool y 3952b144498SSrikar Dronamraju 396d20642f0SRob Herringconfig FIX_EARLYCON_MEM 397d20642f0SRob Herring def_bool y 398d20642f0SRob Herring 39994d49eb3SKirill A. Shutemovconfig DYNAMIC_PHYSICAL_MASK 40094d49eb3SKirill A. Shutemov bool 40194d49eb3SKirill A. Shutemov 40298233368SKirill A. Shutemovconfig PGTABLE_LEVELS 40398233368SKirill A. Shutemov int 40477ef56e4SKirill A. Shutemov default 5 if X86_5LEVEL 40598233368SKirill A. Shutemov default 4 if X86_64 40698233368SKirill A. Shutemov default 3 if X86_PAE 40798233368SKirill A. Shutemov default 2 40898233368SKirill A. Shutemov 4092a61f474SMasahiro Yamadaconfig CC_HAS_SANE_STACKPROTECTOR 4102a61f474SMasahiro Yamada bool 4111b866781SNathan Chancellor default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT 4121b866781SNathan Chancellor default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) 4132a61f474SMasahiro Yamada help 4142a61f474SMasahiro Yamada We have to make sure stack protector is unconditionally disabled if 4153fb0fdb3SAndy Lutomirski the compiler produces broken code or if it does not let us control 4163fb0fdb3SAndy Lutomirski the segment on 32-bit kernels. 4172a61f474SMasahiro Yamada 418506f1d07SSam Ravnborgmenu "Processor type and features" 419506f1d07SSam Ravnborg 420506f1d07SSam Ravnborgconfig SMP 421506f1d07SSam Ravnborg bool "Symmetric multi-processing support" 422a7f7f624SMasahiro Yamada help 423506f1d07SSam Ravnborg This enables support for systems with more than one CPU. If you have 4244a474157SRobert Graffham a system with only one CPU, say N. If you have a system with more 4254a474157SRobert Graffham than one CPU, say Y. 426506f1d07SSam Ravnborg 4274a474157SRobert Graffham If you say N here, the kernel will run on uni- and multiprocessor 428506f1d07SSam Ravnborg machines, but will use only one CPU of a multiprocessor machine. If 429506f1d07SSam Ravnborg you say Y here, the kernel will run on many, but not all, 4304a474157SRobert Graffham uniprocessor machines. On a uniprocessor machine, the kernel 431506f1d07SSam Ravnborg will run faster if you say N here. 432506f1d07SSam Ravnborg 433506f1d07SSam Ravnborg Note that if you say Y here and choose architecture "586" or 434506f1d07SSam Ravnborg "Pentium" under "Processor family", the kernel will not work on 486 435506f1d07SSam Ravnborg architectures. Similarly, multiprocessor kernels for the "PPro" 436506f1d07SSam Ravnborg architecture may not work on all Pentium based boards. 437506f1d07SSam Ravnborg 438506f1d07SSam Ravnborg People using multiprocessor machines who say Y here should also say 439506f1d07SSam Ravnborg Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 440506f1d07SSam Ravnborg Management" code will be disabled if you say Y here. 441506f1d07SSam Ravnborg 442ff61f079SJonathan Corbet See also <file:Documentation/arch/x86/i386/IO-APIC.rst>, 4434f4cfa6cSMauro Carvalho Chehab <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 444506f1d07SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 445506f1d07SSam Ravnborg 446506f1d07SSam Ravnborg If you don't know what to do here, say N. 447506f1d07SSam Ravnborg 44806cd9a7dSYinghai Luconfig X86_X2APIC 44906cd9a7dSYinghai Lu bool "Support x2apic" 45019e3d60dSJan Kiszka depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 451a7f7f624SMasahiro Yamada help 45206cd9a7dSYinghai Lu This enables x2apic support on CPUs that have this feature. 45306cd9a7dSYinghai Lu 45406cd9a7dSYinghai Lu This allows 32-bit apic IDs (so it can support very large systems), 45506cd9a7dSYinghai Lu and accesses the local apic via MSRs not via mmio. 45606cd9a7dSYinghai Lu 457b8d1d163SDaniel Sneddon Some Intel systems circa 2022 and later are locked into x2APIC mode 458b8d1d163SDaniel Sneddon and can not fall back to the legacy APIC modes if SGX or TDX are 459e3998434SMateusz Jończyk enabled in the BIOS. They will boot with very reduced functionality 460e3998434SMateusz Jończyk without enabling this option. 461b8d1d163SDaniel Sneddon 46206cd9a7dSYinghai Lu If you don't know what to do here, say N. 46306cd9a7dSYinghai Lu 4646695c85bSYinghai Luconfig X86_MPPARSE 4654590d98fSAndy Shevchenko bool "Enable MPS table" if ACPI 4667a527688SJan Beulich default y 4675ab74722SIngo Molnar depends on X86_LOCAL_APIC 468a7f7f624SMasahiro Yamada help 4696695c85bSYinghai Lu For old smp systems that do not have proper acpi support. Newer systems 4706695c85bSYinghai Lu (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 4716695c85bSYinghai Lu 472ddd70cf9SJun Nakajimaconfig GOLDFISH 473ddd70cf9SJun Nakajima def_bool y 474ddd70cf9SJun Nakajima depends on X86_GOLDFISH 475ddd70cf9SJun Nakajima 476e6d42931SJohannes Weinerconfig X86_CPU_RESCTRL 477e6d42931SJohannes Weiner bool "x86 CPU resource control support" 4786fe07ce3SBabu Moger depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 47959fe5a77SThomas Gleixner select KERNFS 480e79f15a4SChen Yu select PROC_CPU_RESCTRL if PROC_FS 48178e99b4aSFenghua Yu help 482e6d42931SJohannes Weiner Enable x86 CPU resource control support. 4836fe07ce3SBabu Moger 4846fe07ce3SBabu Moger Provide support for the allocation and monitoring of system resources 4856fe07ce3SBabu Moger usage by the CPU. 4866fe07ce3SBabu Moger 4876fe07ce3SBabu Moger Intel calls this Intel Resource Director Technology 4886fe07ce3SBabu Moger (Intel(R) RDT). More information about RDT can be found in the 4896fe07ce3SBabu Moger Intel x86 Architecture Software Developer Manual. 4906fe07ce3SBabu Moger 4916fe07ce3SBabu Moger AMD calls this AMD Platform Quality of Service (AMD QoS). 4926fe07ce3SBabu Moger More information about AMD QoS can be found in the AMD64 Technology 4936fe07ce3SBabu Moger Platform Quality of Service Extensions manual. 49478e99b4aSFenghua Yu 49578e99b4aSFenghua Yu Say N if unsure. 49678e99b4aSFenghua Yu 4978425091fSRavikiran G Thirumalaiif X86_32 498a0d0bb4dSRandy Dunlapconfig X86_BIGSMP 499a0d0bb4dSRandy Dunlap bool "Support for big SMP systems with more than 8 CPUs" 500a0d0bb4dSRandy Dunlap depends on SMP 501a7f7f624SMasahiro Yamada help 502e133f6eaSRandy Dunlap This option is needed for the systems that have more than 8 CPUs. 503a0d0bb4dSRandy Dunlap 504c5c606d9SRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 505c5c606d9SRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 506c5c606d9SRavikiran G Thirumalai default y 507a7f7f624SMasahiro Yamada help 50806ac8346SIngo Molnar If you disable this option then the kernel will only support 50906ac8346SIngo Molnar standard PC platforms. (which covers the vast majority of 51006ac8346SIngo Molnar systems out there.) 51106ac8346SIngo Molnar 5128425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5138425091fSRavikiran G Thirumalai for the following (non-PC) 32 bit x86 platforms: 514cb7b8023SBen Hutchings Goldfish (Android emulator) 5158425091fSRavikiran G Thirumalai AMD Elan 5168425091fSRavikiran G Thirumalai RDC R-321x SoC 5178425091fSRavikiran G Thirumalai SGI 320/540 (Visual Workstation) 51883125a3aSAlessandro Rubini STA2X11-based (e.g. Northville) 5193f4110a4SThomas Gleixner Moorestown MID devices 52006ac8346SIngo Molnar 52106ac8346SIngo Molnar If you have one of these systems, or if you want to build a 52206ac8346SIngo Molnar generic distribution kernel, say Y here - otherwise say N. 523758cd94aSJuerg Haefligerendif # X86_32 52406ac8346SIngo Molnar 5258425091fSRavikiran G Thirumalaiif X86_64 5268425091fSRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 5278425091fSRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 5288425091fSRavikiran G Thirumalai default y 529a7f7f624SMasahiro Yamada help 5308425091fSRavikiran G Thirumalai If you disable this option then the kernel will only support 5318425091fSRavikiran G Thirumalai standard PC platforms. (which covers the vast majority of 5328425091fSRavikiran G Thirumalai systems out there.) 5338425091fSRavikiran G Thirumalai 5348425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5358425091fSRavikiran G Thirumalai for the following (non-PC) 64 bit x86 platforms: 53644b111b5SSteffen Persvold Numascale NumaChip 5378425091fSRavikiran G Thirumalai ScaleMP vSMP 5388425091fSRavikiran G Thirumalai SGI Ultraviolet 5398425091fSRavikiran G Thirumalai 5408425091fSRavikiran G Thirumalai If you have one of these systems, or if you want to build a 5418425091fSRavikiran G Thirumalai generic distribution kernel, say Y here - otherwise say N. 542758cd94aSJuerg Haefligerendif # X86_64 543c5c606d9SRavikiran G Thirumalai# This is an alphabetically sorted list of 64 bit extended platforms 544c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 54544b111b5SSteffen Persvoldconfig X86_NUMACHIP 54644b111b5SSteffen Persvold bool "Numascale NumaChip" 54744b111b5SSteffen Persvold depends on X86_64 54844b111b5SSteffen Persvold depends on X86_EXTENDED_PLATFORM 54944b111b5SSteffen Persvold depends on NUMA 55044b111b5SSteffen Persvold depends on SMP 55144b111b5SSteffen Persvold depends on X86_X2APIC 552f9726bfdSDaniel J Blueman depends on PCI_MMCONFIG 553a7f7f624SMasahiro Yamada help 55444b111b5SSteffen Persvold Adds support for Numascale NumaChip large-SMP systems. Needed to 55544b111b5SSteffen Persvold enable more than ~168 cores. 55644b111b5SSteffen Persvold If you don't have one of these, you should say N here. 55703b48632SNick Piggin 5586a48565eSIngo Molnarconfig X86_VSMP 559c5c606d9SRavikiran G Thirumalai bool "ScaleMP vSMP" 5606276a074SBorislav Petkov select HYPERVISOR_GUEST 5616a48565eSIngo Molnar select PARAVIRT 5626a48565eSIngo Molnar depends on X86_64 && PCI 563c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 564ead91d4bSShai Fultheim depends on SMP 565a7f7f624SMasahiro Yamada help 5666a48565eSIngo Molnar Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 5676a48565eSIngo Molnar supposed to run on these EM64T-based machines. Only choose this option 5686a48565eSIngo Molnar if you have one of these machines. 5696a48565eSIngo Molnar 570c5c606d9SRavikiran G Thirumalaiconfig X86_UV 571c5c606d9SRavikiran G Thirumalai bool "SGI Ultraviolet" 572c5c606d9SRavikiran G Thirumalai depends on X86_64 573c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 57454c28d29SJack Steiner depends on NUMA 5751ecb4ae5SAndrew Morton depends on EFI 576c2209ea5SIngo Molnar depends on KEXEC_CORE 5779d6c26e7SSuresh Siddha depends on X86_X2APIC 5781222e564SIngo Molnar depends on PCI 579a7f7f624SMasahiro Yamada help 580c5c606d9SRavikiran G Thirumalai This option is needed in order to support SGI Ultraviolet systems. 581c5c606d9SRavikiran G Thirumalai If you don't have one of these, you should say N here. 582c5c606d9SRavikiran G Thirumalai 583c5c606d9SRavikiran G Thirumalai# Following is an alphabetically sorted list of 32 bit extended platforms 584c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 585506f1d07SSam Ravnborg 586ddd70cf9SJun Nakajimaconfig X86_GOLDFISH 587ddd70cf9SJun Nakajima bool "Goldfish (Virtual Platform)" 588cb7b8023SBen Hutchings depends on X86_EXTENDED_PLATFORM 589a7f7f624SMasahiro Yamada help 590ddd70cf9SJun Nakajima Enable support for the Goldfish virtual platform used primarily 591ddd70cf9SJun Nakajima for Android development. Unless you are building for the Android 592ddd70cf9SJun Nakajima Goldfish emulator say N here. 593ddd70cf9SJun Nakajima 594c751e17bSThomas Gleixnerconfig X86_INTEL_CE 595c751e17bSThomas Gleixner bool "CE4100 TV platform" 596c751e17bSThomas Gleixner depends on PCI 597c751e17bSThomas Gleixner depends on PCI_GODIRECT 5986084a6e2SJiang Liu depends on X86_IO_APIC 599c751e17bSThomas Gleixner depends on X86_32 600c751e17bSThomas Gleixner depends on X86_EXTENDED_PLATFORM 60137bc9f50SDirk Brandewie select X86_REBOOTFIXUPS 602da6b737bSSebastian Andrzej Siewior select OF 603da6b737bSSebastian Andrzej Siewior select OF_EARLY_FLATTREE 604a7f7f624SMasahiro Yamada help 605c751e17bSThomas Gleixner Select for the Intel CE media processor (CE4100) SOC. 606c751e17bSThomas Gleixner This option compiles in support for the CE4100 SOC for settop 607c751e17bSThomas Gleixner boxes and media devices. 608c751e17bSThomas Gleixner 6094cb9b00fSDavid Cohenconfig X86_INTEL_MID 61043605ef1SAlan Cox bool "Intel MID platform support" 61143605ef1SAlan Cox depends on X86_EXTENDED_PLATFORM 612edc6bc78SDavid Cohen depends on X86_PLATFORM_DEVICES 6131ea7c673SAlan Cox depends on PCI 6143fda5bb4SAndy Shevchenko depends on X86_64 || (PCI_GOANY && X86_32) 6151ea7c673SAlan Cox depends on X86_IO_APIC 6164cb9b00fSDavid Cohen select I2C 6177c9c3a1eSAlan Cox select DW_APB_TIMER 61854b34aa0SMika Westerberg select INTEL_SCU_PCI 619a7f7f624SMasahiro Yamada help 6204cb9b00fSDavid Cohen Select to build a kernel capable of supporting Intel MID (Mobile 6214cb9b00fSDavid Cohen Internet Device) platform systems which do not have the PCI legacy 6224cb9b00fSDavid Cohen interfaces. If you are building for a PC class system say N here. 6231ea7c673SAlan Cox 6244cb9b00fSDavid Cohen Intel MID platforms are based on an Intel processor and chipset which 6254cb9b00fSDavid Cohen consume less power than most of the x86 derivatives. 62643605ef1SAlan Cox 6278bbc2a13SBryan O'Donoghueconfig X86_INTEL_QUARK 6288bbc2a13SBryan O'Donoghue bool "Intel Quark platform support" 6298bbc2a13SBryan O'Donoghue depends on X86_32 6308bbc2a13SBryan O'Donoghue depends on X86_EXTENDED_PLATFORM 6318bbc2a13SBryan O'Donoghue depends on X86_PLATFORM_DEVICES 6328bbc2a13SBryan O'Donoghue depends on X86_TSC 6338bbc2a13SBryan O'Donoghue depends on PCI 6348bbc2a13SBryan O'Donoghue depends on PCI_GOANY 6358bbc2a13SBryan O'Donoghue depends on X86_IO_APIC 6368bbc2a13SBryan O'Donoghue select IOSF_MBI 6378bbc2a13SBryan O'Donoghue select INTEL_IMR 6389ab6eb51SAndy Shevchenko select COMMON_CLK 639a7f7f624SMasahiro Yamada help 6408bbc2a13SBryan O'Donoghue Select to include support for Quark X1000 SoC. 6418bbc2a13SBryan O'Donoghue Say Y here if you have a Quark based system such as the Arduino 6428bbc2a13SBryan O'Donoghue compatible Intel Galileo. 6438bbc2a13SBryan O'Donoghue 6443d48aab1SMika Westerbergconfig X86_INTEL_LPSS 6453d48aab1SMika Westerberg bool "Intel Low Power Subsystem Support" 6465962dd22SSinan Kaya depends on X86 && ACPI && PCI 6473d48aab1SMika Westerberg select COMMON_CLK 6480f531431SMathias Nyman select PINCTRL 649eebb3e8dSAndy Shevchenko select IOSF_MBI 650a7f7f624SMasahiro Yamada help 6513d48aab1SMika Westerberg Select to build support for Intel Low Power Subsystem such as 6523d48aab1SMika Westerberg found on Intel Lynxpoint PCH. Selecting this option enables 6530f531431SMathias Nyman things like clock tree (common clock framework) and pincontrol 6540f531431SMathias Nyman which are needed by the LPSS peripheral drivers. 6553d48aab1SMika Westerberg 65692082a88SKen Xueconfig X86_AMD_PLATFORM_DEVICE 65792082a88SKen Xue bool "AMD ACPI2Platform devices support" 65892082a88SKen Xue depends on ACPI 65992082a88SKen Xue select COMMON_CLK 66092082a88SKen Xue select PINCTRL 661a7f7f624SMasahiro Yamada help 66292082a88SKen Xue Select to interpret AMD specific ACPI device to platform device 66392082a88SKen Xue such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 66492082a88SKen Xue I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 66592082a88SKen Xue implemented under PINCTRL subsystem. 66692082a88SKen Xue 667ced3ce76SDavid E. Boxconfig IOSF_MBI 668ced3ce76SDavid E. Box tristate "Intel SoC IOSF Sideband support for SoC platforms" 669ced3ce76SDavid E. Box depends on PCI 670a7f7f624SMasahiro Yamada help 671ced3ce76SDavid E. Box This option enables sideband register access support for Intel SoC 672ced3ce76SDavid E. Box platforms. On these platforms the IOSF sideband is used in lieu of 673ced3ce76SDavid E. Box MSR's for some register accesses, mostly but not limited to thermal 674ced3ce76SDavid E. Box and power. Drivers may query the availability of this device to 675ced3ce76SDavid E. Box determine if they need the sideband in order to work on these 676ced3ce76SDavid E. Box platforms. The sideband is available on the following SoC products. 677ced3ce76SDavid E. Box This list is not meant to be exclusive. 678ced3ce76SDavid E. Box - BayTrail 679ced3ce76SDavid E. Box - Braswell 680ced3ce76SDavid E. Box - Quark 681ced3ce76SDavid E. Box 682ced3ce76SDavid E. Box You should say Y if you are running a kernel on one of these SoC's. 683ced3ce76SDavid E. Box 684ed2226bdSDavid E. Boxconfig IOSF_MBI_DEBUG 685ed2226bdSDavid E. Box bool "Enable IOSF sideband access through debugfs" 686ed2226bdSDavid E. Box depends on IOSF_MBI && DEBUG_FS 687a7f7f624SMasahiro Yamada help 688ed2226bdSDavid E. Box Select this option to expose the IOSF sideband access registers (MCR, 689ed2226bdSDavid E. Box MDR, MCRX) through debugfs to write and read register information from 690ed2226bdSDavid E. Box different units on the SoC. This is most useful for obtaining device 691ed2226bdSDavid E. Box state information for debug and analysis. As this is a general access 692ed2226bdSDavid E. Box mechanism, users of this option would have specific knowledge of the 693ed2226bdSDavid E. Box device they want to access. 694ed2226bdSDavid E. Box 695ed2226bdSDavid E. Box If you don't require the option or are in doubt, say N. 696ed2226bdSDavid E. Box 697c5c606d9SRavikiran G Thirumalaiconfig X86_RDC321X 698c5c606d9SRavikiran G Thirumalai bool "RDC R-321x SoC" 699506f1d07SSam Ravnborg depends on X86_32 700c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 701c5c606d9SRavikiran G Thirumalai select M486 702c5c606d9SRavikiran G Thirumalai select X86_REBOOTFIXUPS 703a7f7f624SMasahiro Yamada help 704c5c606d9SRavikiran G Thirumalai This option is needed for RDC R-321x system-on-chip, also known 705c5c606d9SRavikiran G Thirumalai as R-8610-(G). 706c5c606d9SRavikiran G Thirumalai If you don't have one of these chips, you should say N here. 707c5c606d9SRavikiran G Thirumalai 708e0c7ae37SIngo Molnarconfig X86_32_NON_STANDARD 7099c398017SIngo Molnar bool "Support non-standard 32-bit SMP architectures" 7109c398017SIngo Molnar depends on X86_32 && SMP 711c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 712a7f7f624SMasahiro Yamada help 713b5660ba7SH. Peter Anvin This option compiles in the bigsmp and STA2X11 default 714b5660ba7SH. Peter Anvin subarchitectures. It is intended for a generic binary 715b5660ba7SH. Peter Anvin kernel. If you select them all, kernel will probe it one by 716b5660ba7SH. Peter Anvin one and will fallback to default. 717d49c4288SYinghai Lu 718c5c606d9SRavikiran G Thirumalai# Alphabetically sorted list of Non standard 32 bit platforms 719d49c4288SYinghai Lu 720d949f36fSLinus Torvaldsconfig X86_SUPPORTS_MEMORY_FAILURE 7216fc108a0SJan Beulich def_bool y 722d949f36fSLinus Torvalds # MCE code calls memory_failure(): 723d949f36fSLinus Torvalds depends on X86_MCE 724d949f36fSLinus Torvalds # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 725d949f36fSLinus Torvalds # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 726d949f36fSLinus Torvalds depends on X86_64 || !SPARSEMEM 727d949f36fSLinus Torvalds select ARCH_SUPPORTS_MEMORY_FAILURE 728d949f36fSLinus Torvalds 72983125a3aSAlessandro Rubiniconfig STA2X11 73083125a3aSAlessandro Rubini bool "STA2X11 Companion Chip Support" 73183125a3aSAlessandro Rubini depends on X86_32_NON_STANDARD && PCI 73283125a3aSAlessandro Rubini select SWIOTLB 73383125a3aSAlessandro Rubini select MFD_STA2X11 7340145071bSLinus Walleij select GPIOLIB 735a7f7f624SMasahiro Yamada help 73683125a3aSAlessandro Rubini This adds support for boards based on the STA2X11 IO-Hub, 73783125a3aSAlessandro Rubini a.k.a. "ConneXt". The chip is used in place of the standard 73883125a3aSAlessandro Rubini PC chipset, so all "standard" peripherals are missing. If this 73983125a3aSAlessandro Rubini option is selected the kernel will still be able to boot on 74083125a3aSAlessandro Rubini standard PC machines. 74183125a3aSAlessandro Rubini 74282148d1dSShérabconfig X86_32_IRIS 74382148d1dSShérab tristate "Eurobraille/Iris poweroff module" 74482148d1dSShérab depends on X86_32 745a7f7f624SMasahiro Yamada help 74682148d1dSShérab The Iris machines from EuroBraille do not have APM or ACPI support 74782148d1dSShérab to shut themselves down properly. A special I/O sequence is 74882148d1dSShérab needed to do so, which is what this module does at 74982148d1dSShérab kernel shutdown. 75082148d1dSShérab 75182148d1dSShérab This is only for Iris machines from EuroBraille. 75282148d1dSShérab 75382148d1dSShérab If unused, say N. 75482148d1dSShérab 755ae1e9130SIngo Molnarconfig SCHED_OMIT_FRAME_POINTER 7563c2362e6SHarvey Harrison def_bool y 7573c2362e6SHarvey Harrison prompt "Single-depth WCHAN output" 758a87d0914SKen Chen depends on X86 759a7f7f624SMasahiro Yamada help 760506f1d07SSam Ravnborg Calculate simpler /proc/<PID>/wchan values. If this option 761506f1d07SSam Ravnborg is disabled then wchan values will recurse back to the 762506f1d07SSam Ravnborg caller function. This provides more accurate wchan values, 763506f1d07SSam Ravnborg at the expense of slightly more scheduling overhead. 764506f1d07SSam Ravnborg 765506f1d07SSam Ravnborg If in doubt, say "Y". 766506f1d07SSam Ravnborg 7676276a074SBorislav Petkovmenuconfig HYPERVISOR_GUEST 7686276a074SBorislav Petkov bool "Linux guest support" 769a7f7f624SMasahiro Yamada help 7706276a074SBorislav Petkov Say Y here to enable options for running Linux under various hyper- 7716276a074SBorislav Petkov visors. This option enables basic hypervisor detection and platform 7726276a074SBorislav Petkov setup. 773506f1d07SSam Ravnborg 7746276a074SBorislav Petkov If you say N, all options in this submenu will be skipped and 7756276a074SBorislav Petkov disabled, and Linux guest support won't be built in. 776506f1d07SSam Ravnborg 7776276a074SBorislav Petkovif HYPERVISOR_GUEST 778506f1d07SSam Ravnborg 779e61bd94aSEduardo Pereira Habkostconfig PARAVIRT 780e61bd94aSEduardo Pereira Habkost bool "Enable paravirtualization code" 781a0e2bf7cSJuergen Gross depends on HAVE_STATIC_CALL 782a7f7f624SMasahiro Yamada help 783e61bd94aSEduardo Pereira Habkost This changes the kernel so it can modify itself when it is run 784e61bd94aSEduardo Pereira Habkost under a hypervisor, potentially improving performance significantly 785e61bd94aSEduardo Pereira Habkost over full virtualization. However, when run without a hypervisor 786e61bd94aSEduardo Pereira Habkost the kernel is theoretically slower and slightly larger. 787e61bd94aSEduardo Pereira Habkost 788c00a280aSJuergen Grossconfig PARAVIRT_XXL 789c00a280aSJuergen Gross bool 790c00a280aSJuergen Gross 7916276a074SBorislav Petkovconfig PARAVIRT_DEBUG 7926276a074SBorislav Petkov bool "paravirt-ops debugging" 7936276a074SBorislav Petkov depends on PARAVIRT && DEBUG_KERNEL 794a7f7f624SMasahiro Yamada help 7956276a074SBorislav Petkov Enable to debug paravirt_ops internals. Specifically, BUG if 7966276a074SBorislav Petkov a paravirt_op is missing when it is called. 7976276a074SBorislav Petkov 798b4ecc126SJeremy Fitzhardingeconfig PARAVIRT_SPINLOCKS 799b4ecc126SJeremy Fitzhardinge bool "Paravirtualization layer for spinlocks" 8006ea30386SKees Cook depends on PARAVIRT && SMP 801a7f7f624SMasahiro Yamada help 802b4ecc126SJeremy Fitzhardinge Paravirtualized spinlocks allow a pvops backend to replace the 803b4ecc126SJeremy Fitzhardinge spinlock implementation with something virtualization-friendly 804b4ecc126SJeremy Fitzhardinge (for example, block the virtual CPU rather than spinning). 805b4ecc126SJeremy Fitzhardinge 8064c4e4f61SRaghavendra K T It has a minimal impact on native kernels and gives a nice performance 8074c4e4f61SRaghavendra K T benefit on paravirtualized KVM / Xen kernels. 808b4ecc126SJeremy Fitzhardinge 8094c4e4f61SRaghavendra K T If you are unsure how to answer this question, answer Y. 810b4ecc126SJeremy Fitzhardinge 811ecca2502SZhao Yakuiconfig X86_HV_CALLBACK_VECTOR 812ecca2502SZhao Yakui def_bool n 813ecca2502SZhao Yakui 8146276a074SBorislav Petkovsource "arch/x86/xen/Kconfig" 8156276a074SBorislav Petkov 8166276a074SBorislav Petkovconfig KVM_GUEST 8176276a074SBorislav Petkov bool "KVM Guest support (including kvmclock)" 8186276a074SBorislav Petkov depends on PARAVIRT 8196276a074SBorislav Petkov select PARAVIRT_CLOCK 820a1c4423bSMarcelo Tosatti select ARCH_CPUIDLE_HALTPOLL 821b1d40575SVitaly Kuznetsov select X86_HV_CALLBACK_VECTOR 8226276a074SBorislav Petkov default y 823a7f7f624SMasahiro Yamada help 8246276a074SBorislav Petkov This option enables various optimizations for running under the KVM 8256276a074SBorislav Petkov hypervisor. It includes a paravirtualized clock, so that instead 8266276a074SBorislav Petkov of relying on a PIT (or probably other) emulation by the 8276276a074SBorislav Petkov underlying device model, the host provides the guest with 8286276a074SBorislav Petkov timing infrastructure such as time of day, and system time 8296276a074SBorislav Petkov 830a1c4423bSMarcelo Tosatticonfig ARCH_CPUIDLE_HALTPOLL 831a1c4423bSMarcelo Tosatti def_bool n 832a1c4423bSMarcelo Tosatti prompt "Disable host haltpoll when loading haltpoll driver" 833a1c4423bSMarcelo Tosatti help 834a1c4423bSMarcelo Tosatti If virtualized under KVM, disable host haltpoll. 835a1c4423bSMarcelo Tosatti 8367733607fSMaran Wilsonconfig PVH 8377733607fSMaran Wilson bool "Support for running PVH guests" 838a7f7f624SMasahiro Yamada help 8397733607fSMaran Wilson This option enables the PVH entry point for guest virtual machines 8407733607fSMaran Wilson as specified in the x86/HVM direct boot ABI. 8417733607fSMaran Wilson 8426276a074SBorislav Petkovconfig PARAVIRT_TIME_ACCOUNTING 8436276a074SBorislav Petkov bool "Paravirtual steal time accounting" 8446276a074SBorislav Petkov depends on PARAVIRT 845a7f7f624SMasahiro Yamada help 8466276a074SBorislav Petkov Select this option to enable fine granularity task steal time 8476276a074SBorislav Petkov accounting. Time spent executing other tasks in parallel with 8486276a074SBorislav Petkov the current vCPU is discounted from the vCPU power. To account for 8496276a074SBorislav Petkov that, there can be a small performance impact. 8506276a074SBorislav Petkov 8516276a074SBorislav Petkov If in doubt, say N here. 8526276a074SBorislav Petkov 8537af192c9SGerd Hoffmannconfig PARAVIRT_CLOCK 8547af192c9SGerd Hoffmann bool 8557af192c9SGerd Hoffmann 8564a362601SJan Kiszkaconfig JAILHOUSE_GUEST 8574a362601SJan Kiszka bool "Jailhouse non-root cell support" 858abde587bSArnd Bergmann depends on X86_64 && PCI 85987e65d05SJan Kiszka select X86_PM_TIMER 860a7f7f624SMasahiro Yamada help 8614a362601SJan Kiszka This option allows to run Linux as guest in a Jailhouse non-root 8624a362601SJan Kiszka cell. You can leave this option disabled if you only want to start 8634a362601SJan Kiszka Jailhouse and run Linux afterwards in the root cell. 8644a362601SJan Kiszka 865ec7972c9SZhao Yakuiconfig ACRN_GUEST 866ec7972c9SZhao Yakui bool "ACRN Guest support" 867ec7972c9SZhao Yakui depends on X86_64 868498ad393SZhao Yakui select X86_HV_CALLBACK_VECTOR 869ec7972c9SZhao Yakui help 870ec7972c9SZhao Yakui This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 871ec7972c9SZhao Yakui a flexible, lightweight reference open-source hypervisor, built with 872ec7972c9SZhao Yakui real-time and safety-criticality in mind. It is built for embedded 873ec7972c9SZhao Yakui IOT with small footprint and real-time features. More details can be 874ec7972c9SZhao Yakui found in https://projectacrn.org/. 875ec7972c9SZhao Yakui 87659bd54a8SKuppuswamy Sathyanarayananconfig INTEL_TDX_GUEST 87759bd54a8SKuppuswamy Sathyanarayanan bool "Intel TDX (Trust Domain Extensions) - Guest Support" 87859bd54a8SKuppuswamy Sathyanarayanan depends on X86_64 && CPU_SUP_INTEL 87959bd54a8SKuppuswamy Sathyanarayanan depends on X86_X2APIC 88075d090fdSKirill A. Shutemov depends on EFI_STUB 88141394e33SKirill A. Shutemov select ARCH_HAS_CC_PLATFORM 882968b4931SKirill A. Shutemov select X86_MEM_ENCRYPT 88377a512e3SSean Christopherson select X86_MCE 88475d090fdSKirill A. Shutemov select UNACCEPTED_MEMORY 88559bd54a8SKuppuswamy Sathyanarayanan help 88659bd54a8SKuppuswamy Sathyanarayanan Support running as a guest under Intel TDX. Without this support, 88759bd54a8SKuppuswamy Sathyanarayanan the guest kernel can not boot or run under TDX. 88859bd54a8SKuppuswamy Sathyanarayanan TDX includes memory encryption and integrity capabilities 88959bd54a8SKuppuswamy Sathyanarayanan which protect the confidentiality and integrity of guest 89059bd54a8SKuppuswamy Sathyanarayanan memory contents and CPU state. TDX guests are protected from 89159bd54a8SKuppuswamy Sathyanarayanan some attacks from the VMM. 89259bd54a8SKuppuswamy Sathyanarayanan 8936276a074SBorislav Petkovendif # HYPERVISOR_GUEST 89497349135SJeremy Fitzhardinge 895506f1d07SSam Ravnborgsource "arch/x86/Kconfig.cpu" 896506f1d07SSam Ravnborg 897506f1d07SSam Ravnborgconfig HPET_TIMER 8983c2362e6SHarvey Harrison def_bool X86_64 899506f1d07SSam Ravnborg prompt "HPET Timer Support" if X86_32 900a7f7f624SMasahiro Yamada help 901506f1d07SSam Ravnborg Use the IA-PC HPET (High Precision Event Timer) to manage 902506f1d07SSam Ravnborg time in preference to the PIT and RTC, if a HPET is 903506f1d07SSam Ravnborg present. 904506f1d07SSam Ravnborg HPET is the next generation timer replacing legacy 8254s. 905506f1d07SSam Ravnborg The HPET provides a stable time base on SMP 906506f1d07SSam Ravnborg systems, unlike the TSC, but it is more expensive to access, 9074e7f9df2SMichael S. Tsirkin as it is off-chip. The interface used is documented 9084e7f9df2SMichael S. Tsirkin in the HPET spec, revision 1. 909506f1d07SSam Ravnborg 910506f1d07SSam Ravnborg You can safely choose Y here. However, HPET will only be 911506f1d07SSam Ravnborg activated if the platform and the BIOS support this feature. 912506f1d07SSam Ravnborg Otherwise the 8254 will be used for timing services. 913506f1d07SSam Ravnborg 914506f1d07SSam Ravnborg Choose N to continue using the legacy 8254 timer. 915506f1d07SSam Ravnborg 916506f1d07SSam Ravnborgconfig HPET_EMULATE_RTC 9173c2362e6SHarvey Harrison def_bool y 9183228e1dcSAnand K Mistry depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 919506f1d07SSam Ravnborg 9206a108a14SDavid Rientjes# Mark as expert because too many people got it wrong. 921506f1d07SSam Ravnborg# The code disables itself when not needed. 9227ae9392cSThomas Petazzoniconfig DMI 9237ae9392cSThomas Petazzoni default y 924cf074402SArd Biesheuvel select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 9256a108a14SDavid Rientjes bool "Enable DMI scanning" if EXPERT 926a7f7f624SMasahiro Yamada help 9277ae9392cSThomas Petazzoni Enabled scanning of DMI to identify machine quirks. Say Y 9287ae9392cSThomas Petazzoni here unless you have verified that your setup is not 9297ae9392cSThomas Petazzoni affected by entries in the DMI blacklist. Required by PNP 9307ae9392cSThomas Petazzoni BIOS code. 9317ae9392cSThomas Petazzoni 932506f1d07SSam Ravnborgconfig GART_IOMMU 93338901f1cSAndi Kleen bool "Old AMD GART IOMMU support" 9342f9237d4SChristoph Hellwig select DMA_OPS 935a4ce5a48SChristoph Hellwig select IOMMU_HELPER 936506f1d07SSam Ravnborg select SWIOTLB 93723ac4ae8SAndreas Herrmann depends on X86_64 && PCI && AMD_NB 938a7f7f624SMasahiro Yamada help 939ced3c42cSIngo Molnar Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 940ced3c42cSIngo Molnar GART based hardware IOMMUs. 941ced3c42cSIngo Molnar 942ced3c42cSIngo Molnar The GART supports full DMA access for devices with 32-bit access 943ced3c42cSIngo Molnar limitations, on systems with more than 3 GB. This is usually needed 944ced3c42cSIngo Molnar for USB, sound, many IDE/SATA chipsets and some other devices. 945ced3c42cSIngo Molnar 946ced3c42cSIngo Molnar Newer systems typically have a modern AMD IOMMU, supported via 947ced3c42cSIngo Molnar the CONFIG_AMD_IOMMU=y config option. 948ced3c42cSIngo Molnar 949ced3c42cSIngo Molnar In normal configurations this driver is only active when needed: 950ced3c42cSIngo Molnar there's more than 3 GB of memory and the system contains a 951ced3c42cSIngo Molnar 32-bit limited device. 952ced3c42cSIngo Molnar 953ced3c42cSIngo Molnar If unsure, say Y. 954506f1d07SSam Ravnborg 9558b766b0fSMichal Suchanekconfig BOOT_VESA_SUPPORT 9568b766b0fSMichal Suchanek bool 9578b766b0fSMichal Suchanek help 9588b766b0fSMichal Suchanek If true, at least one selected framebuffer driver can take advantage 9598b766b0fSMichal Suchanek of VESA video modes set at an early boot stage via the vga= parameter. 9608b766b0fSMichal Suchanek 9611184dc2fSMike Travisconfig MAXSMP 962ddb0c5a6SSamuel Thibault bool "Enable Maximum number of SMP Processors and NUMA Nodes" 9636ea30386SKees Cook depends on X86_64 && SMP && DEBUG_KERNEL 96436f5101aSMike Travis select CPUMASK_OFFSTACK 965a7f7f624SMasahiro Yamada help 966ddb0c5a6SSamuel Thibault Enable maximum number of CPUS and NUMA Nodes for this architecture. 9671184dc2fSMike Travis If unsure, say N. 968506f1d07SSam Ravnborg 969aec6487eSIngo Molnar# 970aec6487eSIngo Molnar# The maximum number of CPUs supported: 971aec6487eSIngo Molnar# 972aec6487eSIngo Molnar# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 973aec6487eSIngo Molnar# and which can be configured interactively in the 974aec6487eSIngo Molnar# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 975aec6487eSIngo Molnar# 976aec6487eSIngo Molnar# The ranges are different on 32-bit and 64-bit kernels, depending on 977aec6487eSIngo Molnar# hardware capabilities and scalability features of the kernel. 978aec6487eSIngo Molnar# 979aec6487eSIngo Molnar# ( If MAXSMP is enabled we just use the highest possible value and disable 980aec6487eSIngo Molnar# interactive configuration. ) 981aec6487eSIngo Molnar# 982a0d0bb4dSRandy Dunlap 983aec6487eSIngo Molnarconfig NR_CPUS_RANGE_BEGIN 984a0d0bb4dSRandy Dunlap int 985aec6487eSIngo Molnar default NR_CPUS_RANGE_END if MAXSMP 986a0d0bb4dSRandy Dunlap default 1 if !SMP 987a0d0bb4dSRandy Dunlap default 2 988a0d0bb4dSRandy Dunlap 989aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 990a0d0bb4dSRandy Dunlap int 991a0d0bb4dSRandy Dunlap depends on X86_32 992aec6487eSIngo Molnar default 64 if SMP && X86_BIGSMP 993aec6487eSIngo Molnar default 8 if SMP && !X86_BIGSMP 994a0d0bb4dSRandy Dunlap default 1 if !SMP 995a0d0bb4dSRandy Dunlap 996aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 997a0d0bb4dSRandy Dunlap int 998a0d0bb4dSRandy Dunlap depends on X86_64 9991edae1aeSScott Wood default 8192 if SMP && CPUMASK_OFFSTACK 10001edae1aeSScott Wood default 512 if SMP && !CPUMASK_OFFSTACK 1001a0d0bb4dSRandy Dunlap default 1 if !SMP 1002aec6487eSIngo Molnar 1003aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 1004aec6487eSIngo Molnar int 1005aec6487eSIngo Molnar depends on X86_32 1006aec6487eSIngo Molnar default 32 if X86_BIGSMP 1007aec6487eSIngo Molnar default 8 if SMP 1008aec6487eSIngo Molnar default 1 if !SMP 1009aec6487eSIngo Molnar 1010aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 1011aec6487eSIngo Molnar int 1012aec6487eSIngo Molnar depends on X86_64 1013a0d0bb4dSRandy Dunlap default 8192 if MAXSMP 1014a0d0bb4dSRandy Dunlap default 64 if SMP 1015aec6487eSIngo Molnar default 1 if !SMP 1016a0d0bb4dSRandy Dunlap 1017506f1d07SSam Ravnborgconfig NR_CPUS 101836f5101aSMike Travis int "Maximum number of CPUs" if SMP && !MAXSMP 1019aec6487eSIngo Molnar range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1020aec6487eSIngo Molnar default NR_CPUS_DEFAULT 1021a7f7f624SMasahiro Yamada help 1022506f1d07SSam Ravnborg This allows you to specify the maximum number of CPUs which this 1023bb61ccc7SJosh Boyer kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1024cad14bb9SKirill A. Shutemov supported value is 8192, otherwise the maximum value is 512. The 1025506f1d07SSam Ravnborg minimum value which makes sense is 2. 1026506f1d07SSam Ravnborg 1027aec6487eSIngo Molnar This is purely to save memory: each supported CPU adds about 8KB 1028aec6487eSIngo Molnar to the kernel image. 1029506f1d07SSam Ravnborg 103066558b73STim Chenconfig SCHED_CLUSTER 103166558b73STim Chen bool "Cluster scheduler support" 103266558b73STim Chen depends on SMP 103366558b73STim Chen default y 103466558b73STim Chen help 103566558b73STim Chen Cluster scheduler support improves the CPU scheduler's decision 103666558b73STim Chen making when dealing with machines that have clusters of CPUs. 103766558b73STim Chen Cluster usually means a couple of CPUs which are placed closely 103866558b73STim Chen by sharing mid-level caches, last-level cache tags or internal 103966558b73STim Chen busses. 104066558b73STim Chen 1041506f1d07SSam Ravnborgconfig SCHED_SMT 1042dbe73364SThomas Gleixner def_bool y if SMP 1043506f1d07SSam Ravnborg 1044506f1d07SSam Ravnborgconfig SCHED_MC 10453c2362e6SHarvey Harrison def_bool y 10463c2362e6SHarvey Harrison prompt "Multi-core scheduler support" 1047c8e56d20SBorislav Petkov depends on SMP 1048a7f7f624SMasahiro Yamada help 1049506f1d07SSam Ravnborg Multi-core scheduler support improves the CPU scheduler's decision 1050506f1d07SSam Ravnborg making when dealing with multi-core CPU chips at a cost of slightly 1051506f1d07SSam Ravnborg increased overhead in some places. If unsure say N here. 1052506f1d07SSam Ravnborg 1053de966cf4STim Chenconfig SCHED_MC_PRIO 1054de966cf4STim Chen bool "CPU core priorities scheduler support" 10550a21fc12SIngo Molnar depends on SCHED_MC && CPU_SUP_INTEL 10560a21fc12SIngo Molnar select X86_INTEL_PSTATE 10570a21fc12SIngo Molnar select CPU_FREQ 1058de966cf4STim Chen default y 1059a7f7f624SMasahiro Yamada help 1060de966cf4STim Chen Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1061de966cf4STim Chen core ordering determined at manufacturing time, which allows 1062de966cf4STim Chen certain cores to reach higher turbo frequencies (when running 1063de966cf4STim Chen single threaded workloads) than others. 1064de966cf4STim Chen 1065de966cf4STim Chen Enabling this kernel feature teaches the scheduler about 1066de966cf4STim Chen the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1067de966cf4STim Chen scheduler's CPU selection logic accordingly, so that higher 1068de966cf4STim Chen overall system performance can be achieved. 1069de966cf4STim Chen 1070de966cf4STim Chen This feature will have no effect on CPUs without this feature. 1071de966cf4STim Chen 1072de966cf4STim Chen If unsure say Y here. 10735e76b2abSTim Chen 107430b8b006SThomas Gleixnerconfig UP_LATE_INIT 107530b8b006SThomas Gleixner def_bool y 1076ba360f88SThomas Gleixner depends on !SMP && X86_LOCAL_APIC 107730b8b006SThomas Gleixner 1078506f1d07SSam Ravnborgconfig X86_UP_APIC 107950849eefSJan Beulich bool "Local APIC support on uniprocessors" if !PCI_MSI 108050849eefSJan Beulich default PCI_MSI 108138a1dfdaSBryan O'Donoghue depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1082a7f7f624SMasahiro Yamada help 1083506f1d07SSam Ravnborg A local APIC (Advanced Programmable Interrupt Controller) is an 1084506f1d07SSam Ravnborg integrated interrupt controller in the CPU. If you have a single-CPU 1085506f1d07SSam Ravnborg system which has a processor with a local APIC, you can say Y here to 1086506f1d07SSam Ravnborg enable and use it. If you say Y here even though your machine doesn't 1087506f1d07SSam Ravnborg have a local APIC, then the kernel will still run with no slowdown at 1088506f1d07SSam Ravnborg all. The local APIC supports CPU-generated self-interrupts (timer, 1089506f1d07SSam Ravnborg performance counters), and the NMI watchdog which detects hard 1090506f1d07SSam Ravnborg lockups. 1091506f1d07SSam Ravnborg 1092506f1d07SSam Ravnborgconfig X86_UP_IOAPIC 1093506f1d07SSam Ravnborg bool "IO-APIC support on uniprocessors" 1094506f1d07SSam Ravnborg depends on X86_UP_APIC 1095a7f7f624SMasahiro Yamada help 1096506f1d07SSam Ravnborg An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1097506f1d07SSam Ravnborg SMP-capable replacement for PC-style interrupt controllers. Most 1098506f1d07SSam Ravnborg SMP systems and many recent uniprocessor systems have one. 1099506f1d07SSam Ravnborg 1100506f1d07SSam Ravnborg If you have a single-CPU system with an IO-APIC, you can say Y here 1101506f1d07SSam Ravnborg to use it. If you say Y here even though your machine doesn't have 1102506f1d07SSam Ravnborg an IO-APIC, then the kernel will still run with no slowdown at all. 1103506f1d07SSam Ravnborg 1104506f1d07SSam Ravnborgconfig X86_LOCAL_APIC 11053c2362e6SHarvey Harrison def_bool y 11060dbc6078SThomas Petazzoni depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1107b5dc8e6cSJiang Liu select IRQ_DOMAIN_HIERARCHY 1108506f1d07SSam Ravnborg 1109506f1d07SSam Ravnborgconfig X86_IO_APIC 1110b1da1e71SJan Beulich def_bool y 1111b1da1e71SJan Beulich depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1112506f1d07SSam Ravnborg 111341b9eb26SStefan Assmannconfig X86_REROUTE_FOR_BROKEN_BOOT_IRQS 111441b9eb26SStefan Assmann bool "Reroute for broken boot IRQs" 111541b9eb26SStefan Assmann depends on X86_IO_APIC 1116a7f7f624SMasahiro Yamada help 111741b9eb26SStefan Assmann This option enables a workaround that fixes a source of 111841b9eb26SStefan Assmann spurious interrupts. This is recommended when threaded 111941b9eb26SStefan Assmann interrupt handling is used on systems where the generation of 112041b9eb26SStefan Assmann superfluous "boot interrupts" cannot be disabled. 112141b9eb26SStefan Assmann 112241b9eb26SStefan Assmann Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 112341b9eb26SStefan Assmann entry in the chipset's IO-APIC is masked (as, e.g. the RT 112441b9eb26SStefan Assmann kernel does during interrupt handling). On chipsets where this 112541b9eb26SStefan Assmann boot IRQ generation cannot be disabled, this workaround keeps 112641b9eb26SStefan Assmann the original IRQ line masked so that only the equivalent "boot 112741b9eb26SStefan Assmann IRQ" is delivered to the CPUs. The workaround also tells the 112841b9eb26SStefan Assmann kernel to set up the IRQ handler on the boot IRQ line. In this 112941b9eb26SStefan Assmann way only one interrupt is delivered to the kernel. Otherwise 113041b9eb26SStefan Assmann the spurious second interrupt may cause the kernel to bring 113141b9eb26SStefan Assmann down (vital) interrupt lines. 113241b9eb26SStefan Assmann 113341b9eb26SStefan Assmann Only affects "broken" chipsets. Interrupt sharing may be 113441b9eb26SStefan Assmann increased on these systems. 113541b9eb26SStefan Assmann 1136506f1d07SSam Ravnborgconfig X86_MCE 1137bab9bc65SAndi Kleen bool "Machine Check / overheating reporting" 1138648ed940SChen, Gong select GENERIC_ALLOCATOR 1139e57dbaf7SBorislav Petkov default y 1140a7f7f624SMasahiro Yamada help 1141bab9bc65SAndi Kleen Machine Check support allows the processor to notify the 1142bab9bc65SAndi Kleen kernel if it detects a problem (e.g. overheating, data corruption). 1143506f1d07SSam Ravnborg The action the kernel takes depends on the severity of the problem, 1144bab9bc65SAndi Kleen ranging from warning messages to halting the machine. 11454efc0670SAndi Kleen 11465de97c9fSTony Luckconfig X86_MCELOG_LEGACY 11475de97c9fSTony Luck bool "Support for deprecated /dev/mcelog character device" 11485de97c9fSTony Luck depends on X86_MCE 1149a7f7f624SMasahiro Yamada help 11505de97c9fSTony Luck Enable support for /dev/mcelog which is needed by the old mcelog 11515de97c9fSTony Luck userspace logging daemon. Consider switching to the new generation 11525de97c9fSTony Luck rasdaemon solution. 11535de97c9fSTony Luck 1154506f1d07SSam Ravnborgconfig X86_MCE_INTEL 11553c2362e6SHarvey Harrison def_bool y 11563c2362e6SHarvey Harrison prompt "Intel MCE features" 1157c1ebf835SAndi Kleen depends on X86_MCE && X86_LOCAL_APIC 1158a7f7f624SMasahiro Yamada help 1159506f1d07SSam Ravnborg Additional support for intel specific MCE features such as 1160506f1d07SSam Ravnborg the thermal monitor. 1161506f1d07SSam Ravnborg 1162506f1d07SSam Ravnborgconfig X86_MCE_AMD 11633c2362e6SHarvey Harrison def_bool y 11643c2362e6SHarvey Harrison prompt "AMD MCE features" 1165f5382de9SYazen Ghannam depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1166a7f7f624SMasahiro Yamada help 1167506f1d07SSam Ravnborg Additional support for AMD specific MCE features such as 1168506f1d07SSam Ravnborg the DRAM Error Threshold. 1169506f1d07SSam Ravnborg 11704efc0670SAndi Kleenconfig X86_ANCIENT_MCE 11716fc108a0SJan Beulich bool "Support for old Pentium 5 / WinChip machine checks" 1172c31d9633SAndi Kleen depends on X86_32 && X86_MCE 1173a7f7f624SMasahiro Yamada help 11744efc0670SAndi Kleen Include support for machine check handling on old Pentium 5 or WinChip 11755065a706SMasanari Iida systems. These typically need to be enabled explicitly on the command 11764efc0670SAndi Kleen line. 11774efc0670SAndi Kleen 1178b2762686SAndi Kleenconfig X86_MCE_THRESHOLD 1179b2762686SAndi Kleen depends on X86_MCE_AMD || X86_MCE_INTEL 11806fc108a0SJan Beulich def_bool y 1181b2762686SAndi Kleen 1182ea149b36SAndi Kleenconfig X86_MCE_INJECT 1183bc8e80d5SBorislav Petkov depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1184ea149b36SAndi Kleen tristate "Machine check injector support" 1185a7f7f624SMasahiro Yamada help 1186ea149b36SAndi Kleen Provide support for injecting machine checks for testing purposes. 1187ea149b36SAndi Kleen If you don't know what a machine check is and you don't do kernel 1188ea149b36SAndi Kleen QA it is safe to say n. 1189ea149b36SAndi Kleen 119007dc900eSPeter Zijlstrasource "arch/x86/events/Kconfig" 1191e633c65aSKan Liang 11925aef51c3SAndy Lutomirskiconfig X86_LEGACY_VM86 11931e642812SIngo Molnar bool "Legacy VM86 support" 1194506f1d07SSam Ravnborg depends on X86_32 1195a7f7f624SMasahiro Yamada help 11965aef51c3SAndy Lutomirski This option allows user programs to put the CPU into V8086 11975aef51c3SAndy Lutomirski mode, which is an 80286-era approximation of 16-bit real mode. 11985aef51c3SAndy Lutomirski 11995aef51c3SAndy Lutomirski Some very old versions of X and/or vbetool require this option 12005aef51c3SAndy Lutomirski for user mode setting. Similarly, DOSEMU will use it if 12015aef51c3SAndy Lutomirski available to accelerate real mode DOS programs. However, any 12025aef51c3SAndy Lutomirski recent version of DOSEMU, X, or vbetool should be fully 12035aef51c3SAndy Lutomirski functional even without kernel VM86 support, as they will all 12041e642812SIngo Molnar fall back to software emulation. Nevertheless, if you are using 12051e642812SIngo Molnar a 16-bit DOS program where 16-bit performance matters, vm86 12061e642812SIngo Molnar mode might be faster than emulation and you might want to 12071e642812SIngo Molnar enable this option. 12085aef51c3SAndy Lutomirski 12091e642812SIngo Molnar Note that any app that works on a 64-bit kernel is unlikely to 12101e642812SIngo Molnar need this option, as 64-bit kernels don't, and can't, support 12111e642812SIngo Molnar V8086 mode. This option is also unrelated to 16-bit protected 12121e642812SIngo Molnar mode and is not needed to run most 16-bit programs under Wine. 12135aef51c3SAndy Lutomirski 12141e642812SIngo Molnar Enabling this option increases the complexity of the kernel 12151e642812SIngo Molnar and slows down exception handling a tiny bit. 12165aef51c3SAndy Lutomirski 12171e642812SIngo Molnar If unsure, say N here. 12185aef51c3SAndy Lutomirski 12195aef51c3SAndy Lutomirskiconfig VM86 12205aef51c3SAndy Lutomirski bool 12215aef51c3SAndy Lutomirski default X86_LEGACY_VM86 122234273f41SH. Peter Anvin 122334273f41SH. Peter Anvinconfig X86_16BIT 122434273f41SH. Peter Anvin bool "Enable support for 16-bit segments" if EXPERT 122534273f41SH. Peter Anvin default y 1226a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 1227a7f7f624SMasahiro Yamada help 122834273f41SH. Peter Anvin This option is required by programs like Wine to run 16-bit 122934273f41SH. Peter Anvin protected mode legacy code on x86 processors. Disabling 123034273f41SH. Peter Anvin this option saves about 300 bytes on i386, or around 6K text 123134273f41SH. Peter Anvin plus 16K runtime memory on x86-64, 123234273f41SH. Peter Anvin 123334273f41SH. Peter Anvinconfig X86_ESPFIX32 123434273f41SH. Peter Anvin def_bool y 123534273f41SH. Peter Anvin depends on X86_16BIT && X86_32 1236506f1d07SSam Ravnborg 1237197725deSH. Peter Anvinconfig X86_ESPFIX64 1238197725deSH. Peter Anvin def_bool y 123934273f41SH. Peter Anvin depends on X86_16BIT && X86_64 1240506f1d07SSam Ravnborg 12411ad83c85SAndy Lutomirskiconfig X86_VSYSCALL_EMULATION 12421ad83c85SAndy Lutomirski bool "Enable vsyscall emulation" if EXPERT 12431ad83c85SAndy Lutomirski default y 12441ad83c85SAndy Lutomirski depends on X86_64 1245a7f7f624SMasahiro Yamada help 12461ad83c85SAndy Lutomirski This enables emulation of the legacy vsyscall page. Disabling 12471ad83c85SAndy Lutomirski it is roughly equivalent to booting with vsyscall=none, except 12481ad83c85SAndy Lutomirski that it will also disable the helpful warning if a program 12491ad83c85SAndy Lutomirski tries to use a vsyscall. With this option set to N, offending 12501ad83c85SAndy Lutomirski programs will just segfault, citing addresses of the form 12511ad83c85SAndy Lutomirski 0xffffffffff600?00. 12521ad83c85SAndy Lutomirski 12531ad83c85SAndy Lutomirski This option is required by many programs built before 2013, and 12541ad83c85SAndy Lutomirski care should be used even with newer programs if set to N. 12551ad83c85SAndy Lutomirski 12561ad83c85SAndy Lutomirski Disabling this option saves about 7K of kernel size and 12571ad83c85SAndy Lutomirski possibly 4K of additional runtime pagetable memory. 12581ad83c85SAndy Lutomirski 1259111e7b15SThomas Gleixnerconfig X86_IOPL_IOPERM 1260111e7b15SThomas Gleixner bool "IOPERM and IOPL Emulation" 1261a24ca997SThomas Gleixner default y 1262a7f7f624SMasahiro Yamada help 1263111e7b15SThomas Gleixner This enables the ioperm() and iopl() syscalls which are necessary 1264111e7b15SThomas Gleixner for legacy applications. 1265111e7b15SThomas Gleixner 1266c8137aceSThomas Gleixner Legacy IOPL support is an overbroad mechanism which allows user 1267c8137aceSThomas Gleixner space aside of accessing all 65536 I/O ports also to disable 1268c8137aceSThomas Gleixner interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1269c8137aceSThomas Gleixner capabilities and permission from potentially active security 1270c8137aceSThomas Gleixner modules. 1271c8137aceSThomas Gleixner 1272c8137aceSThomas Gleixner The emulation restricts the functionality of the syscall to 1273c8137aceSThomas Gleixner only allowing the full range I/O port access, but prevents the 1274a24ca997SThomas Gleixner ability to disable interrupts from user space which would be 1275a24ca997SThomas Gleixner granted if the hardware IOPL mechanism would be used. 1276c8137aceSThomas Gleixner 1277506f1d07SSam Ravnborgconfig TOSHIBA 1278506f1d07SSam Ravnborg tristate "Toshiba Laptop support" 1279506f1d07SSam Ravnborg depends on X86_32 1280a7f7f624SMasahiro Yamada help 1281506f1d07SSam Ravnborg This adds a driver to safely access the System Management Mode of 1282506f1d07SSam Ravnborg the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1283506f1d07SSam Ravnborg not work on models with a Phoenix BIOS. The System Management Mode 1284506f1d07SSam Ravnborg is used to set the BIOS and power saving options on Toshiba portables. 1285506f1d07SSam Ravnborg 1286506f1d07SSam Ravnborg For information on utilities to make use of this driver see the 1287506f1d07SSam Ravnborg Toshiba Linux utilities web site at: 1288506f1d07SSam Ravnborg <http://www.buzzard.org.uk/toshiba/>. 1289506f1d07SSam Ravnborg 1290506f1d07SSam Ravnborg Say Y if you intend to run this kernel on a Toshiba portable. 1291506f1d07SSam Ravnborg Say N otherwise. 1292506f1d07SSam Ravnborg 1293506f1d07SSam Ravnborgconfig X86_REBOOTFIXUPS 12949ba16087SJan Beulich bool "Enable X86 board specific fixups for reboot" 12959ba16087SJan Beulich depends on X86_32 1296a7f7f624SMasahiro Yamada help 1297506f1d07SSam Ravnborg This enables chipset and/or board specific fixups to be done 1298506f1d07SSam Ravnborg in order to get reboot to work correctly. This is only needed on 1299506f1d07SSam Ravnborg some combinations of hardware and BIOS. The symptom, for which 1300506f1d07SSam Ravnborg this config is intended, is when reboot ends with a stalled/hung 1301506f1d07SSam Ravnborg system. 1302506f1d07SSam Ravnborg 1303506f1d07SSam Ravnborg Currently, the only fixup is for the Geode machines using 13045e3a77e9SFlorian Fainelli CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1305506f1d07SSam Ravnborg 1306506f1d07SSam Ravnborg Say Y if you want to enable the fixup. Currently, it's safe to 1307506f1d07SSam Ravnborg enable this option even if you don't need it. 1308506f1d07SSam Ravnborg Say N otherwise. 1309506f1d07SSam Ravnborg 1310506f1d07SSam Ravnborgconfig MICROCODE 1311*e6bcfdd7SThomas Gleixner def_bool y 131280030e3dSBorislav Petkov depends on CPU_SUP_AMD || CPU_SUP_INTEL 131380cc9f10SPeter Oruba 1314a77a94f8SBorislav Petkovconfig MICROCODE_LATE_LOADING 1315a77a94f8SBorislav Petkov bool "Late microcode loading (DANGEROUS)" 1316c02f48e0SBorislav Petkov default n 1317506f1d07SSam Ravnborg depends on MICROCODE 1318a7f7f624SMasahiro Yamada help 1319a77a94f8SBorislav Petkov Loading microcode late, when the system is up and executing instructions 1320a77a94f8SBorislav Petkov is a tricky business and should be avoided if possible. Just the sequence 1321a77a94f8SBorislav Petkov of synchronizing all cores and SMT threads is one fragile dance which does 1322a77a94f8SBorislav Petkov not guarantee that cores might not softlock after the loading. Therefore, 1323a77a94f8SBorislav Petkov use this at your own risk. Late loading taints the kernel too. 1324506f1d07SSam Ravnborg 1325506f1d07SSam Ravnborgconfig X86_MSR 1326506f1d07SSam Ravnborg tristate "/dev/cpu/*/msr - Model-specific register support" 1327a7f7f624SMasahiro Yamada help 1328506f1d07SSam Ravnborg This device gives privileged processes access to the x86 1329506f1d07SSam Ravnborg Model-Specific Registers (MSRs). It is a character device with 1330506f1d07SSam Ravnborg major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1331506f1d07SSam Ravnborg MSR accesses are directed to a specific CPU on multi-processor 1332506f1d07SSam Ravnborg systems. 1333506f1d07SSam Ravnborg 1334506f1d07SSam Ravnborgconfig X86_CPUID 1335506f1d07SSam Ravnborg tristate "/dev/cpu/*/cpuid - CPU information support" 1336a7f7f624SMasahiro Yamada help 1337506f1d07SSam Ravnborg This device gives processes access to the x86 CPUID instruction to 1338506f1d07SSam Ravnborg be executed on a specific processor. It is a character device 1339506f1d07SSam Ravnborg with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1340506f1d07SSam Ravnborg /dev/cpu/31/cpuid. 1341506f1d07SSam Ravnborg 1342506f1d07SSam Ravnborgchoice 1343506f1d07SSam Ravnborg prompt "High Memory Support" 13446fc108a0SJan Beulich default HIGHMEM4G 1345506f1d07SSam Ravnborg depends on X86_32 1346506f1d07SSam Ravnborg 1347506f1d07SSam Ravnborgconfig NOHIGHMEM 1348506f1d07SSam Ravnborg bool "off" 1349a7f7f624SMasahiro Yamada help 1350506f1d07SSam Ravnborg Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1351506f1d07SSam Ravnborg However, the address space of 32-bit x86 processors is only 4 1352506f1d07SSam Ravnborg Gigabytes large. That means that, if you have a large amount of 1353506f1d07SSam Ravnborg physical memory, not all of it can be "permanently mapped" by the 1354506f1d07SSam Ravnborg kernel. The physical memory that's not permanently mapped is called 1355506f1d07SSam Ravnborg "high memory". 1356506f1d07SSam Ravnborg 1357506f1d07SSam Ravnborg If you are compiling a kernel which will never run on a machine with 1358506f1d07SSam Ravnborg more than 1 Gigabyte total physical RAM, answer "off" here (default 1359506f1d07SSam Ravnborg choice and suitable for most users). This will result in a "3GB/1GB" 1360506f1d07SSam Ravnborg split: 3GB are mapped so that each process sees a 3GB virtual memory 1361506f1d07SSam Ravnborg space and the remaining part of the 4GB virtual memory space is used 1362506f1d07SSam Ravnborg by the kernel to permanently map as much physical memory as 1363506f1d07SSam Ravnborg possible. 1364506f1d07SSam Ravnborg 1365506f1d07SSam Ravnborg If the machine has between 1 and 4 Gigabytes physical RAM, then 1366506f1d07SSam Ravnborg answer "4GB" here. 1367506f1d07SSam Ravnborg 1368506f1d07SSam Ravnborg If more than 4 Gigabytes is used then answer "64GB" here. This 1369506f1d07SSam Ravnborg selection turns Intel PAE (Physical Address Extension) mode on. 1370506f1d07SSam Ravnborg PAE implements 3-level paging on IA32 processors. PAE is fully 1371506f1d07SSam Ravnborg supported by Linux, PAE mode is implemented on all recent Intel 1372506f1d07SSam Ravnborg processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1373506f1d07SSam Ravnborg then the kernel will not boot on CPUs that don't support PAE! 1374506f1d07SSam Ravnborg 1375506f1d07SSam Ravnborg The actual amount of total physical memory will either be 1376506f1d07SSam Ravnborg auto detected or can be forced by using a kernel command line option 1377506f1d07SSam Ravnborg such as "mem=256M". (Try "man bootparam" or see the documentation of 1378506f1d07SSam Ravnborg your boot loader (lilo or loadlin) about how to pass options to the 1379506f1d07SSam Ravnborg kernel at boot time.) 1380506f1d07SSam Ravnborg 1381506f1d07SSam Ravnborg If unsure, say "off". 1382506f1d07SSam Ravnborg 1383506f1d07SSam Ravnborgconfig HIGHMEM4G 1384506f1d07SSam Ravnborg bool "4GB" 1385a7f7f624SMasahiro Yamada help 1386506f1d07SSam Ravnborg Select this if you have a 32-bit processor and between 1 and 4 1387506f1d07SSam Ravnborg gigabytes of physical RAM. 1388506f1d07SSam Ravnborg 1389506f1d07SSam Ravnborgconfig HIGHMEM64G 1390506f1d07SSam Ravnborg bool "64GB" 1391225bac2dSLukas Bulwahn depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6 1392506f1d07SSam Ravnborg select X86_PAE 1393a7f7f624SMasahiro Yamada help 1394506f1d07SSam Ravnborg Select this if you have a 32-bit processor and more than 4 1395506f1d07SSam Ravnborg gigabytes of physical RAM. 1396506f1d07SSam Ravnborg 1397506f1d07SSam Ravnborgendchoice 1398506f1d07SSam Ravnborg 1399506f1d07SSam Ravnborgchoice 14006a108a14SDavid Rientjes prompt "Memory split" if EXPERT 1401506f1d07SSam Ravnborg default VMSPLIT_3G 1402506f1d07SSam Ravnborg depends on X86_32 1403a7f7f624SMasahiro Yamada help 1404506f1d07SSam Ravnborg Select the desired split between kernel and user memory. 1405506f1d07SSam Ravnborg 1406506f1d07SSam Ravnborg If the address range available to the kernel is less than the 1407506f1d07SSam Ravnborg physical memory installed, the remaining memory will be available 1408506f1d07SSam Ravnborg as "high memory". Accessing high memory is a little more costly 1409506f1d07SSam Ravnborg than low memory, as it needs to be mapped into the kernel first. 1410506f1d07SSam Ravnborg Note that increasing the kernel address space limits the range 1411506f1d07SSam Ravnborg available to user programs, making the address space there 1412506f1d07SSam Ravnborg tighter. Selecting anything other than the default 3G/1G split 1413506f1d07SSam Ravnborg will also likely make your kernel incompatible with binary-only 1414506f1d07SSam Ravnborg kernel modules. 1415506f1d07SSam Ravnborg 1416506f1d07SSam Ravnborg If you are not absolutely sure what you are doing, leave this 1417506f1d07SSam Ravnborg option alone! 1418506f1d07SSam Ravnborg 1419506f1d07SSam Ravnborg config VMSPLIT_3G 1420506f1d07SSam Ravnborg bool "3G/1G user/kernel split" 1421506f1d07SSam Ravnborg config VMSPLIT_3G_OPT 1422506f1d07SSam Ravnborg depends on !X86_PAE 1423506f1d07SSam Ravnborg bool "3G/1G user/kernel split (for full 1G low memory)" 1424506f1d07SSam Ravnborg config VMSPLIT_2G 1425506f1d07SSam Ravnborg bool "2G/2G user/kernel split" 1426506f1d07SSam Ravnborg config VMSPLIT_2G_OPT 1427506f1d07SSam Ravnborg depends on !X86_PAE 1428506f1d07SSam Ravnborg bool "2G/2G user/kernel split (for full 2G low memory)" 1429506f1d07SSam Ravnborg config VMSPLIT_1G 1430506f1d07SSam Ravnborg bool "1G/3G user/kernel split" 1431506f1d07SSam Ravnborgendchoice 1432506f1d07SSam Ravnborg 1433506f1d07SSam Ravnborgconfig PAGE_OFFSET 1434506f1d07SSam Ravnborg hex 1435506f1d07SSam Ravnborg default 0xB0000000 if VMSPLIT_3G_OPT 1436506f1d07SSam Ravnborg default 0x80000000 if VMSPLIT_2G 1437506f1d07SSam Ravnborg default 0x78000000 if VMSPLIT_2G_OPT 1438506f1d07SSam Ravnborg default 0x40000000 if VMSPLIT_1G 1439506f1d07SSam Ravnborg default 0xC0000000 1440506f1d07SSam Ravnborg depends on X86_32 1441506f1d07SSam Ravnborg 1442506f1d07SSam Ravnborgconfig HIGHMEM 14433c2362e6SHarvey Harrison def_bool y 1444506f1d07SSam Ravnborg depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1445506f1d07SSam Ravnborg 1446506f1d07SSam Ravnborgconfig X86_PAE 14479ba16087SJan Beulich bool "PAE (Physical Address Extension) Support" 1448506f1d07SSam Ravnborg depends on X86_32 && !HIGHMEM4G 1449d4a451d5SChristoph Hellwig select PHYS_ADDR_T_64BIT 14509d99c712SChristian Melki select SWIOTLB 1451a7f7f624SMasahiro Yamada help 1452506f1d07SSam Ravnborg PAE is required for NX support, and furthermore enables 1453506f1d07SSam Ravnborg larger swapspace support for non-overcommit purposes. It 1454506f1d07SSam Ravnborg has the cost of more pagetable lookup overhead, and also 1455506f1d07SSam Ravnborg consumes more pagetable space per process. 1456506f1d07SSam Ravnborg 145777ef56e4SKirill A. Shutemovconfig X86_5LEVEL 145877ef56e4SKirill A. Shutemov bool "Enable 5-level page tables support" 145918ec1eafSKirill A. Shutemov default y 1460eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 1461162434e7SKirill A. Shutemov select SPARSEMEM_VMEMMAP 146277ef56e4SKirill A. Shutemov depends on X86_64 1463a7f7f624SMasahiro Yamada help 146477ef56e4SKirill A. Shutemov 5-level paging enables access to larger address space: 146577ef56e4SKirill A. Shutemov up to 128 PiB of virtual address space and 4 PiB of 146677ef56e4SKirill A. Shutemov physical address space. 146777ef56e4SKirill A. Shutemov 146877ef56e4SKirill A. Shutemov It will be supported by future Intel CPUs. 146977ef56e4SKirill A. Shutemov 14706657fca0SKirill A. Shutemov A kernel with the option enabled can be booted on machines that 14716657fca0SKirill A. Shutemov support 4- or 5-level paging. 147277ef56e4SKirill A. Shutemov 1473ff61f079SJonathan Corbet See Documentation/arch/x86/x86_64/5level-paging.rst for more 147477ef56e4SKirill A. Shutemov information. 147577ef56e4SKirill A. Shutemov 147677ef56e4SKirill A. Shutemov Say N if unsure. 147777ef56e4SKirill A. Shutemov 147810971ab2SIngo Molnarconfig X86_DIRECT_GBPAGES 1479e5008abeSLuis R. Rodriguez def_bool y 14802e1da13fSVlastimil Babka depends on X86_64 1481a7f7f624SMasahiro Yamada help 148210971ab2SIngo Molnar Certain kernel features effectively disable kernel 148310971ab2SIngo Molnar linear 1 GB mappings (even if the CPU otherwise 148410971ab2SIngo Molnar supports them), so don't confuse the user by printing 148510971ab2SIngo Molnar that we have them enabled. 14869e899816SNick Piggin 14875c280cf6SThomas Gleixnerconfig X86_CPA_STATISTICS 14885c280cf6SThomas Gleixner bool "Enable statistic for Change Page Attribute" 14895c280cf6SThomas Gleixner depends on DEBUG_FS 1490a7f7f624SMasahiro Yamada help 1491b75baaf3SIngo Molnar Expose statistics about the Change Page Attribute mechanism, which 1492a943245aSColin Ian King helps to determine the effectiveness of preserving large and huge 14935c280cf6SThomas Gleixner page mappings when mapping protections are changed. 14945c280cf6SThomas Gleixner 149520f07a04SKirill A. Shutemovconfig X86_MEM_ENCRYPT 149620f07a04SKirill A. Shutemov select ARCH_HAS_FORCE_DMA_UNENCRYPTED 149720f07a04SKirill A. Shutemov select DYNAMIC_PHYSICAL_MASK 149820f07a04SKirill A. Shutemov def_bool n 149920f07a04SKirill A. Shutemov 15007744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT 15017744ccdbSTom Lendacky bool "AMD Secure Memory Encryption (SME) support" 15027744ccdbSTom Lendacky depends on X86_64 && CPU_SUP_AMD 15036c321179STom Lendacky depends on EFI_STUB 150482fef0adSDavid Rientjes select DMA_COHERENT_POOL 1505ce9084baSArd Biesheuvel select ARCH_USE_MEMREMAP_PROT 1506597cfe48SJoerg Roedel select INSTRUCTION_DECODER 1507aa5a4611STom Lendacky select ARCH_HAS_CC_PLATFORM 150820f07a04SKirill A. Shutemov select X86_MEM_ENCRYPT 15096c321179STom Lendacky select UNACCEPTED_MEMORY 1510a7f7f624SMasahiro Yamada help 15117744ccdbSTom Lendacky Say yes to enable support for the encryption of system memory. 15127744ccdbSTom Lendacky This requires an AMD processor that supports Secure Memory 15137744ccdbSTom Lendacky Encryption (SME). 15147744ccdbSTom Lendacky 15157744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 15167744ccdbSTom Lendacky bool "Activate AMD Secure Memory Encryption (SME) by default" 15177744ccdbSTom Lendacky depends on AMD_MEM_ENCRYPT 1518a7f7f624SMasahiro Yamada help 15197744ccdbSTom Lendacky Say yes to have system memory encrypted by default if running on 15207744ccdbSTom Lendacky an AMD processor that supports Secure Memory Encryption (SME). 15217744ccdbSTom Lendacky 15227744ccdbSTom Lendacky If set to Y, then the encryption of system memory can be 15237744ccdbSTom Lendacky deactivated with the mem_encrypt=off command line option. 15247744ccdbSTom Lendacky 15257744ccdbSTom Lendacky If set to N, then the encryption of system memory can be 15267744ccdbSTom Lendacky activated with the mem_encrypt=on command line option. 15277744ccdbSTom Lendacky 1528506f1d07SSam Ravnborg# Common NUMA Features 1529506f1d07SSam Ravnborgconfig NUMA 1530e133f6eaSRandy Dunlap bool "NUMA Memory Allocation and Scheduler Support" 1531506f1d07SSam Ravnborg depends on SMP 1532b5660ba7SH. Peter Anvin depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1533b5660ba7SH. Peter Anvin default y if X86_BIGSMP 15347ecd19cfSKefeng Wang select USE_PERCPU_NUMA_NODE_ID 1535a7f7f624SMasahiro Yamada help 1536e133f6eaSRandy Dunlap Enable NUMA (Non-Uniform Memory Access) support. 1537fd51b2d7SKOSAKI Motohiro 1538506f1d07SSam Ravnborg The kernel will try to allocate memory used by a CPU on the 1539506f1d07SSam Ravnborg local memory controller of the CPU and add some more 1540506f1d07SSam Ravnborg NUMA awareness to the kernel. 1541506f1d07SSam Ravnborg 1542c280ea5eSIngo Molnar For 64-bit this is recommended if the system is Intel Core i7 1543fd51b2d7SKOSAKI Motohiro (or later), AMD Opteron, or EM64T NUMA. 1544fd51b2d7SKOSAKI Motohiro 1545b5660ba7SH. Peter Anvin For 32-bit this is only needed if you boot a 32-bit 15467cf6c945SDavid Rientjes kernel on a 64-bit NUMA platform. 1547fd51b2d7SKOSAKI Motohiro 1548fd51b2d7SKOSAKI Motohiro Otherwise, you should say N. 1549506f1d07SSam Ravnborg 1550eec1d4faSHans Rosenfeldconfig AMD_NUMA 15513c2362e6SHarvey Harrison def_bool y 15523c2362e6SHarvey Harrison prompt "Old style AMD Opteron NUMA detection" 15535da0ef9aSTejun Heo depends on X86_64 && NUMA && PCI 1554a7f7f624SMasahiro Yamada help 1555eec1d4faSHans Rosenfeld Enable AMD NUMA node topology detection. You should say Y here if 1556eec1d4faSHans Rosenfeld you have a multi processor AMD system. This uses an old method to 1557eec1d4faSHans Rosenfeld read the NUMA configuration directly from the builtin Northbridge 1558eec1d4faSHans Rosenfeld of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1559eec1d4faSHans Rosenfeld which also takes priority if both are compiled in. 1560506f1d07SSam Ravnborg 1561506f1d07SSam Ravnborgconfig X86_64_ACPI_NUMA 15623c2362e6SHarvey Harrison def_bool y 15633c2362e6SHarvey Harrison prompt "ACPI NUMA detection" 1564506f1d07SSam Ravnborg depends on X86_64 && NUMA && ACPI && PCI 1565506f1d07SSam Ravnborg select ACPI_NUMA 1566a7f7f624SMasahiro Yamada help 1567506f1d07SSam Ravnborg Enable ACPI SRAT based node topology detection. 1568506f1d07SSam Ravnborg 1569506f1d07SSam Ravnborgconfig NUMA_EMU 1570506f1d07SSam Ravnborg bool "NUMA emulation" 15711b7e03efSTejun Heo depends on NUMA 1572a7f7f624SMasahiro Yamada help 1573506f1d07SSam Ravnborg Enable NUMA emulation. A flat machine will be split 1574506f1d07SSam Ravnborg into virtual nodes when booted with "numa=fake=N", where N is the 1575506f1d07SSam Ravnborg number of nodes. This is only useful for debugging. 1576506f1d07SSam Ravnborg 1577506f1d07SSam Ravnborgconfig NODES_SHIFT 1578d25e26b6SLinus Torvalds int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 157951591e31SDavid Rientjes range 1 10 158051591e31SDavid Rientjes default "10" if MAXSMP 1581506f1d07SSam Ravnborg default "6" if X86_64 1582506f1d07SSam Ravnborg default "3" 1583a9ee6cf5SMike Rapoport depends on NUMA 1584a7f7f624SMasahiro Yamada help 15851184dc2fSMike Travis Specify the maximum number of NUMA Nodes available on the target 1586692105b8SMatt LaPlante system. Increases memory reserved to accommodate various tables. 1587506f1d07SSam Ravnborg 1588506f1d07SSam Ravnborgconfig ARCH_FLATMEM_ENABLE 1589506f1d07SSam Ravnborg def_bool y 15903b16651fSTejun Heo depends on X86_32 && !NUMA 1591506f1d07SSam Ravnborg 1592506f1d07SSam Ravnborgconfig ARCH_SPARSEMEM_ENABLE 1593506f1d07SSam Ravnborg def_bool y 15946ea30386SKees Cook depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1595506f1d07SSam Ravnborg select SPARSEMEM_STATIC if X86_32 1596506f1d07SSam Ravnborg select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1597506f1d07SSam Ravnborg 15983b16651fSTejun Heoconfig ARCH_SPARSEMEM_DEFAULT 15996ad57f7fSMike Rapoport def_bool X86_64 || (NUMA && X86_32) 16003b16651fSTejun Heo 1601506f1d07SSam Ravnborgconfig ARCH_SELECT_MEMORY_MODEL 1602506f1d07SSam Ravnborg def_bool y 16034eda2bc3SDavid Hildenbrand depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE 1604506f1d07SSam Ravnborg 1605506f1d07SSam Ravnborgconfig ARCH_MEMORY_PROBE 1606a0842b70SToshi Kani bool "Enable sysfs memory/probe interface" 16075c11f00bSDavid Hildenbrand depends on MEMORY_HOTPLUG 1608a0842b70SToshi Kani help 1609a0842b70SToshi Kani This option enables a sysfs memory/probe interface for testing. 1610cb1aaebeSMauro Carvalho Chehab See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1611a0842b70SToshi Kani If you are unsure how to answer this question, answer N. 1612506f1d07SSam Ravnborg 16133b16651fSTejun Heoconfig ARCH_PROC_KCORE_TEXT 16143b16651fSTejun Heo def_bool y 16153b16651fSTejun Heo depends on X86_64 && PROC_KCORE 16163b16651fSTejun Heo 1617a29815a3SAvi Kivityconfig ILLEGAL_POINTER_VALUE 1618a29815a3SAvi Kivity hex 1619a29815a3SAvi Kivity default 0 if X86_32 1620a29815a3SAvi Kivity default 0xdead000000000000 if X86_64 1621a29815a3SAvi Kivity 16227a67832cSDan Williamsconfig X86_PMEM_LEGACY_DEVICE 16237a67832cSDan Williams bool 16247a67832cSDan Williams 1625ec776ef6SChristoph Hellwigconfig X86_PMEM_LEGACY 16267a67832cSDan Williams tristate "Support non-standard NVDIMMs and ADR protected memory" 16279f53f9faSDan Williams depends on PHYS_ADDR_T_64BIT 16289f53f9faSDan Williams depends on BLK_DEV 16297a67832cSDan Williams select X86_PMEM_LEGACY_DEVICE 16307b27a862SDan Williams select NUMA_KEEP_MEMINFO if NUMA 16319f53f9faSDan Williams select LIBNVDIMM 1632ec776ef6SChristoph Hellwig help 1633ec776ef6SChristoph Hellwig Treat memory marked using the non-standard e820 type of 12 as used 1634ec776ef6SChristoph Hellwig by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1635ec776ef6SChristoph Hellwig The kernel will offer these regions to the 'pmem' driver so 1636ec776ef6SChristoph Hellwig they can be used for persistent storage. 1637ec776ef6SChristoph Hellwig 1638ec776ef6SChristoph Hellwig Say Y if unsure. 1639ec776ef6SChristoph Hellwig 1640506f1d07SSam Ravnborgconfig HIGHPTE 1641506f1d07SSam Ravnborg bool "Allocate 3rd-level pagetables from highmem" 16426fc108a0SJan Beulich depends on HIGHMEM 1643a7f7f624SMasahiro Yamada help 1644506f1d07SSam Ravnborg The VM uses one page table entry for each page of physical memory. 1645506f1d07SSam Ravnborg For systems with a lot of RAM, this can be wasteful of precious 1646506f1d07SSam Ravnborg low memory. Setting this option will put user-space page table 1647506f1d07SSam Ravnborg entries in high memory. 1648506f1d07SSam Ravnborg 16499f077871SJeremy Fitzhardingeconfig X86_CHECK_BIOS_CORRUPTION 16509f077871SJeremy Fitzhardinge bool "Check for low memory corruption" 1651a7f7f624SMasahiro Yamada help 16529f077871SJeremy Fitzhardinge Periodically check for memory corruption in low memory, which 16539f077871SJeremy Fitzhardinge is suspected to be caused by BIOS. Even when enabled in the 16549f077871SJeremy Fitzhardinge configuration, it is disabled at runtime. Enable it by 16559f077871SJeremy Fitzhardinge setting "memory_corruption_check=1" on the kernel command 16569f077871SJeremy Fitzhardinge line. By default it scans the low 64k of memory every 60 16579f077871SJeremy Fitzhardinge seconds; see the memory_corruption_check_size and 16589f077871SJeremy Fitzhardinge memory_corruption_check_period parameters in 16598c27ceffSMauro Carvalho Chehab Documentation/admin-guide/kernel-parameters.rst to adjust this. 16609f077871SJeremy Fitzhardinge 16619f077871SJeremy Fitzhardinge When enabled with the default parameters, this option has 16629f077871SJeremy Fitzhardinge almost no overhead, as it reserves a relatively small amount 16639f077871SJeremy Fitzhardinge of memory and scans it infrequently. It both detects corruption 16649f077871SJeremy Fitzhardinge and prevents it from affecting the running system. 16659f077871SJeremy Fitzhardinge 16669f077871SJeremy Fitzhardinge It is, however, intended as a diagnostic tool; if repeatable 16679f077871SJeremy Fitzhardinge BIOS-originated corruption always affects the same memory, 16689f077871SJeremy Fitzhardinge you can use memmap= to prevent the kernel from using that 16699f077871SJeremy Fitzhardinge memory. 16709f077871SJeremy Fitzhardinge 1671c885df50SJeremy Fitzhardingeconfig X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1672c885df50SJeremy Fitzhardinge bool "Set the default setting of memory_corruption_check" 1673c885df50SJeremy Fitzhardinge depends on X86_CHECK_BIOS_CORRUPTION 1674c885df50SJeremy Fitzhardinge default y 1675a7f7f624SMasahiro Yamada help 1676c885df50SJeremy Fitzhardinge Set whether the default state of memory_corruption_check is 1677c885df50SJeremy Fitzhardinge on or off. 1678c885df50SJeremy Fitzhardinge 1679506f1d07SSam Ravnborgconfig MATH_EMULATION 1680506f1d07SSam Ravnborg bool 1681a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 168287d6021bSArnd Bergmann prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1683a7f7f624SMasahiro Yamada help 1684506f1d07SSam Ravnborg Linux can emulate a math coprocessor (used for floating point 1685506f1d07SSam Ravnborg operations) if you don't have one. 486DX and Pentium processors have 1686506f1d07SSam Ravnborg a math coprocessor built in, 486SX and 386 do not, unless you added 1687506f1d07SSam Ravnborg a 487DX or 387, respectively. (The messages during boot time can 1688506f1d07SSam Ravnborg give you some hints here ["man dmesg"].) Everyone needs either a 1689506f1d07SSam Ravnborg coprocessor or this emulation. 1690506f1d07SSam Ravnborg 1691506f1d07SSam Ravnborg If you don't have a math coprocessor, you need to say Y here; if you 1692506f1d07SSam Ravnborg say Y here even though you have a coprocessor, the coprocessor will 1693506f1d07SSam Ravnborg be used nevertheless. (This behavior can be changed with the kernel 1694506f1d07SSam Ravnborg command line option "no387", which comes handy if your coprocessor 1695506f1d07SSam Ravnborg is broken. Try "man bootparam" or see the documentation of your boot 1696506f1d07SSam Ravnborg loader (lilo or loadlin) about how to pass options to the kernel at 1697506f1d07SSam Ravnborg boot time.) This means that it is a good idea to say Y here if you 1698506f1d07SSam Ravnborg intend to use this kernel on different machines. 1699506f1d07SSam Ravnborg 1700506f1d07SSam Ravnborg More information about the internals of the Linux math coprocessor 1701506f1d07SSam Ravnborg emulation can be found in <file:arch/x86/math-emu/README>. 1702506f1d07SSam Ravnborg 1703506f1d07SSam Ravnborg If you are not sure, say Y; apart from resulting in a 66 KB bigger 1704506f1d07SSam Ravnborg kernel, it won't hurt. 1705506f1d07SSam Ravnborg 1706506f1d07SSam Ravnborgconfig MTRR 17076fc108a0SJan Beulich def_bool y 17086a108a14SDavid Rientjes prompt "MTRR (Memory Type Range Register) support" if EXPERT 1709a7f7f624SMasahiro Yamada help 1710506f1d07SSam Ravnborg On Intel P6 family processors (Pentium Pro, Pentium II and later) 1711506f1d07SSam Ravnborg the Memory Type Range Registers (MTRRs) may be used to control 1712506f1d07SSam Ravnborg processor access to memory ranges. This is most useful if you have 1713506f1d07SSam Ravnborg a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1714506f1d07SSam Ravnborg allows bus write transfers to be combined into a larger transfer 1715506f1d07SSam Ravnborg before bursting over the PCI/AGP bus. This can increase performance 1716506f1d07SSam Ravnborg of image write operations 2.5 times or more. Saying Y here creates a 1717506f1d07SSam Ravnborg /proc/mtrr file which may be used to manipulate your processor's 1718506f1d07SSam Ravnborg MTRRs. Typically the X server should use this. 1719506f1d07SSam Ravnborg 1720506f1d07SSam Ravnborg This code has a reasonably generic interface so that similar 1721506f1d07SSam Ravnborg control registers on other processors can be easily supported 1722506f1d07SSam Ravnborg as well: 1723506f1d07SSam Ravnborg 1724506f1d07SSam Ravnborg The Cyrix 6x86, 6x86MX and M II processors have Address Range 1725506f1d07SSam Ravnborg Registers (ARRs) which provide a similar functionality to MTRRs. For 1726506f1d07SSam Ravnborg these, the ARRs are used to emulate the MTRRs. 1727506f1d07SSam Ravnborg The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1728506f1d07SSam Ravnborg MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1729506f1d07SSam Ravnborg write-combining. All of these processors are supported by this code 1730506f1d07SSam Ravnborg and it makes sense to say Y here if you have one of them. 1731506f1d07SSam Ravnborg 1732506f1d07SSam Ravnborg Saying Y here also fixes a problem with buggy SMP BIOSes which only 1733506f1d07SSam Ravnborg set the MTRRs for the boot CPU and not for the secondary CPUs. This 1734506f1d07SSam Ravnborg can lead to all sorts of problems, so it's good to say Y here. 1735506f1d07SSam Ravnborg 1736506f1d07SSam Ravnborg You can safely say Y even if your machine doesn't have MTRRs, you'll 1737506f1d07SSam Ravnborg just add about 9 KB to your kernel. 1738506f1d07SSam Ravnborg 1739ff61f079SJonathan Corbet See <file:Documentation/arch/x86/mtrr.rst> for more information. 1740506f1d07SSam Ravnborg 174195ffa243SYinghai Luconfig MTRR_SANITIZER 17422ffb3501SYinghai Lu def_bool y 174395ffa243SYinghai Lu prompt "MTRR cleanup support" 174495ffa243SYinghai Lu depends on MTRR 1745a7f7f624SMasahiro Yamada help 1746aba3728cSThomas Gleixner Convert MTRR layout from continuous to discrete, so X drivers can 1747aba3728cSThomas Gleixner add writeback entries. 174895ffa243SYinghai Lu 1749aba3728cSThomas Gleixner Can be disabled with disable_mtrr_cleanup on the kernel command line. 1750692105b8SMatt LaPlante The largest mtrr entry size for a continuous block can be set with 1751aba3728cSThomas Gleixner mtrr_chunk_size. 175295ffa243SYinghai Lu 17532ffb3501SYinghai Lu If unsure, say Y. 175495ffa243SYinghai Lu 175595ffa243SYinghai Luconfig MTRR_SANITIZER_ENABLE_DEFAULT 1756f5098d62SYinghai Lu int "MTRR cleanup enable value (0-1)" 1757f5098d62SYinghai Lu range 0 1 1758f5098d62SYinghai Lu default "0" 175995ffa243SYinghai Lu depends on MTRR_SANITIZER 1760a7f7f624SMasahiro Yamada help 1761f5098d62SYinghai Lu Enable mtrr cleanup default value 176295ffa243SYinghai Lu 176312031a62SYinghai Luconfig MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 176412031a62SYinghai Lu int "MTRR cleanup spare reg num (0-7)" 176512031a62SYinghai Lu range 0 7 176612031a62SYinghai Lu default "1" 176712031a62SYinghai Lu depends on MTRR_SANITIZER 1768a7f7f624SMasahiro Yamada help 176912031a62SYinghai Lu mtrr cleanup spare entries default, it can be changed via 1770aba3728cSThomas Gleixner mtrr_spare_reg_nr=N on the kernel command line. 177112031a62SYinghai Lu 17722e5d9c85Svenkatesh.pallipadi@intel.comconfig X86_PAT 17736fc108a0SJan Beulich def_bool y 17746a108a14SDavid Rientjes prompt "x86 PAT support" if EXPERT 17752a8a2719SIngo Molnar depends on MTRR 1776a7f7f624SMasahiro Yamada help 17772e5d9c85Svenkatesh.pallipadi@intel.com Use PAT attributes to setup page level cache control. 1778042b78e4SVenki Pallipadi 17792e5d9c85Svenkatesh.pallipadi@intel.com PATs are the modern equivalents of MTRRs and are much more 17802e5d9c85Svenkatesh.pallipadi@intel.com flexible than MTRRs. 17812e5d9c85Svenkatesh.pallipadi@intel.com 17822e5d9c85Svenkatesh.pallipadi@intel.com Say N here if you see bootup problems (boot crash, boot hang, 1783042b78e4SVenki Pallipadi spontaneous reboots) or a non-working video driver. 17842e5d9c85Svenkatesh.pallipadi@intel.com 17852e5d9c85Svenkatesh.pallipadi@intel.com If unsure, say Y. 17862e5d9c85Svenkatesh.pallipadi@intel.com 178746cf98cdSVenkatesh Pallipadiconfig ARCH_USES_PG_UNCACHED 178846cf98cdSVenkatesh Pallipadi def_bool y 178946cf98cdSVenkatesh Pallipadi depends on X86_PAT 179046cf98cdSVenkatesh Pallipadi 1791b971880fSBabu Mogerconfig X86_UMIP 1792796ebc81SRicardo Neri def_bool y 1793b971880fSBabu Moger prompt "User Mode Instruction Prevention" if EXPERT 1794a7f7f624SMasahiro Yamada help 1795b971880fSBabu Moger User Mode Instruction Prevention (UMIP) is a security feature in 1796b971880fSBabu Moger some x86 processors. If enabled, a general protection fault is 1797b971880fSBabu Moger issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1798b971880fSBabu Moger executed in user mode. These instructions unnecessarily expose 1799b971880fSBabu Moger information about the hardware state. 1800796ebc81SRicardo Neri 1801796ebc81SRicardo Neri The vast majority of applications do not use these instructions. 1802796ebc81SRicardo Neri For the very few that do, software emulation is provided in 1803796ebc81SRicardo Neri specific cases in protected and virtual-8086 modes. Emulated 1804796ebc81SRicardo Neri results are dummy. 1805aa35f896SRicardo Neri 1806156ff4a5SPeter Zijlstraconfig CC_HAS_IBT 1807156ff4a5SPeter Zijlstra # GCC >= 9 and binutils >= 2.29 1808156ff4a5SPeter Zijlstra # Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654 1809156ff4a5SPeter Zijlstra # Clang/LLVM >= 14 1810262448f3SNathan Chancellor # https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f 1811262448f3SNathan Chancellor # https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332 1812156ff4a5SPeter Zijlstra def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \ 1813262448f3SNathan Chancellor (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \ 1814156ff4a5SPeter Zijlstra $(as-instr,endbr64) 1815156ff4a5SPeter Zijlstra 1816156ff4a5SPeter Zijlstraconfig X86_KERNEL_IBT 1817156ff4a5SPeter Zijlstra prompt "Indirect Branch Tracking" 18184fd5f70cSKees Cook def_bool y 181903f16cd0SJosh Poimboeuf depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL 1820f6a2c2b2SNathan Chancellor # https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f 1821f6a2c2b2SNathan Chancellor depends on !LD_IS_LLD || LLD_VERSION >= 140000 182203f16cd0SJosh Poimboeuf select OBJTOOL 1823156ff4a5SPeter Zijlstra help 1824156ff4a5SPeter Zijlstra Build the kernel with support for Indirect Branch Tracking, a 1825156ff4a5SPeter Zijlstra hardware support course-grain forward-edge Control Flow Integrity 1826156ff4a5SPeter Zijlstra protection. It enforces that all indirect calls must land on 1827156ff4a5SPeter Zijlstra an ENDBR instruction, as such, the compiler will instrument the 1828156ff4a5SPeter Zijlstra code with them to make this happen. 1829156ff4a5SPeter Zijlstra 1830ed53a0d9SPeter Zijlstra In addition to building the kernel with IBT, seal all functions that 18314cdfc11bSNur Hussein are not indirect call targets, avoiding them ever becoming one. 1832ed53a0d9SPeter Zijlstra 1833ed53a0d9SPeter Zijlstra This requires LTO like objtool runs and will slow down the build. It 1834ed53a0d9SPeter Zijlstra does significantly reduce the number of ENDBR instructions in the 1835ed53a0d9SPeter Zijlstra kernel image. 1836ed53a0d9SPeter Zijlstra 183735e97790SDave Hansenconfig X86_INTEL_MEMORY_PROTECTION_KEYS 183838f3e775SBabu Moger prompt "Memory Protection Keys" 183935e97790SDave Hansen def_bool y 1840284244a9SDave Hansen # Note: only available in 64-bit mode 184138f3e775SBabu Moger depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 184252c8e601SIngo Molnar select ARCH_USES_HIGH_VMA_FLAGS 184352c8e601SIngo Molnar select ARCH_HAS_PKEYS 1844a7f7f624SMasahiro Yamada help 1845284244a9SDave Hansen Memory Protection Keys provides a mechanism for enforcing 1846284244a9SDave Hansen page-based protections, but without requiring modification of the 1847284244a9SDave Hansen page tables when an application changes protection domains. 1848284244a9SDave Hansen 18491eecbcdcSMauro Carvalho Chehab For details, see Documentation/core-api/protection-keys.rst 1850284244a9SDave Hansen 1851284244a9SDave Hansen If unsure, say y. 185235e97790SDave Hansen 1853db616173SMichal Hockochoice 1854db616173SMichal Hocko prompt "TSX enable mode" 1855db616173SMichal Hocko depends on CPU_SUP_INTEL 1856db616173SMichal Hocko default X86_INTEL_TSX_MODE_OFF 1857db616173SMichal Hocko help 1858db616173SMichal Hocko Intel's TSX (Transactional Synchronization Extensions) feature 1859db616173SMichal Hocko allows to optimize locking protocols through lock elision which 1860db616173SMichal Hocko can lead to a noticeable performance boost. 1861db616173SMichal Hocko 1862db616173SMichal Hocko On the other hand it has been shown that TSX can be exploited 1863db616173SMichal Hocko to form side channel attacks (e.g. TAA) and chances are there 1864db616173SMichal Hocko will be more of those attacks discovered in the future. 1865db616173SMichal Hocko 1866db616173SMichal Hocko Therefore TSX is not enabled by default (aka tsx=off). An admin 1867db616173SMichal Hocko might override this decision by tsx=on the command line parameter. 1868db616173SMichal Hocko Even with TSX enabled, the kernel will attempt to enable the best 1869db616173SMichal Hocko possible TAA mitigation setting depending on the microcode available 1870db616173SMichal Hocko for the particular machine. 1871db616173SMichal Hocko 1872db616173SMichal Hocko This option allows to set the default tsx mode between tsx=on, =off 1873db616173SMichal Hocko and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1874db616173SMichal Hocko details. 1875db616173SMichal Hocko 1876db616173SMichal Hocko Say off if not sure, auto if TSX is in use but it should be used on safe 1877db616173SMichal Hocko platforms or on if TSX is in use and the security aspect of tsx is not 1878db616173SMichal Hocko relevant. 1879db616173SMichal Hocko 1880db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_OFF 1881db616173SMichal Hocko bool "off" 1882db616173SMichal Hocko help 1883db616173SMichal Hocko TSX is disabled if possible - equals to tsx=off command line parameter. 1884db616173SMichal Hocko 1885db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_ON 1886db616173SMichal Hocko bool "on" 1887db616173SMichal Hocko help 1888db616173SMichal Hocko TSX is always enabled on TSX capable HW - equals the tsx=on command 1889db616173SMichal Hocko line parameter. 1890db616173SMichal Hocko 1891db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_AUTO 1892db616173SMichal Hocko bool "auto" 1893db616173SMichal Hocko help 1894db616173SMichal Hocko TSX is enabled on TSX capable HW that is believed to be safe against 1895db616173SMichal Hocko side channel attacks- equals the tsx=auto command line parameter. 1896db616173SMichal Hockoendchoice 1897db616173SMichal Hocko 1898e7e05452SSean Christophersonconfig X86_SGX 1899e7e05452SSean Christopherson bool "Software Guard eXtensions (SGX)" 1900b8d1d163SDaniel Sneddon depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC 1901e7e05452SSean Christopherson depends on CRYPTO=y 1902e7e05452SSean Christopherson depends on CRYPTO_SHA256=y 1903e7e05452SSean Christopherson select MMU_NOTIFIER 1904901ddbb9SJarkko Sakkinen select NUMA_KEEP_MEMINFO if NUMA 190540e0e784STony Luck select XARRAY_MULTI 1906e7e05452SSean Christopherson help 1907e7e05452SSean Christopherson Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1908e7e05452SSean Christopherson that can be used by applications to set aside private regions of code 1909e7e05452SSean Christopherson and data, referred to as enclaves. An enclave's private memory can 1910e7e05452SSean Christopherson only be accessed by code running within the enclave. Accesses from 1911e7e05452SSean Christopherson outside the enclave, including other enclaves, are disallowed by 1912e7e05452SSean Christopherson hardware. 1913e7e05452SSean Christopherson 1914e7e05452SSean Christopherson If unsure, say N. 1915e7e05452SSean Christopherson 1916506f1d07SSam Ravnborgconfig EFI 19179ba16087SJan Beulich bool "EFI runtime service support" 19185b83683fSHuang, Ying depends on ACPI 1919f6ce5002SSergey Vlasov select UCS2_STRING 1920022ee6c5SArd Biesheuvel select EFI_RUNTIME_WRAPPERS 19211ff2fc02STom Lendacky select ARCH_USE_MEMREMAP_PROT 1922a7f7f624SMasahiro Yamada help 19238b2cb7a8SHuang, Ying This enables the kernel to use EFI runtime services that are 1924506f1d07SSam Ravnborg available (such as the EFI variable services). 1925506f1d07SSam Ravnborg 19268b2cb7a8SHuang, Ying This option is only useful on systems that have EFI firmware. 19278b2cb7a8SHuang, Ying In addition, you should use the latest ELILO loader available 19288b2cb7a8SHuang, Ying at <http://elilo.sourceforge.net> in order to take advantage 19298b2cb7a8SHuang, Ying of EFI runtime services. However, even with this option, the 19308b2cb7a8SHuang, Ying resultant kernel should continue to boot on existing non-EFI 19318b2cb7a8SHuang, Ying platforms. 1932506f1d07SSam Ravnborg 1933291f3632SMatt Flemingconfig EFI_STUB 1934291f3632SMatt Fleming bool "EFI stub support" 1935c6dbd3e5SPeter Zijlstra depends on EFI 19367b2a583aSMatt Fleming select RELOCATABLE 1937a7f7f624SMasahiro Yamada help 1938291f3632SMatt Fleming This kernel feature allows a bzImage to be loaded directly 1939291f3632SMatt Fleming by EFI firmware without the use of a bootloader. 1940291f3632SMatt Fleming 19414f4cfa6cSMauro Carvalho Chehab See Documentation/admin-guide/efi-stub.rst for more information. 19420c759662SMatt Fleming 1943cc3fdda2SArd Biesheuvelconfig EFI_HANDOVER_PROTOCOL 1944cc3fdda2SArd Biesheuvel bool "EFI handover protocol (DEPRECATED)" 1945cc3fdda2SArd Biesheuvel depends on EFI_STUB 1946cc3fdda2SArd Biesheuvel default y 1947cc3fdda2SArd Biesheuvel help 1948cc3fdda2SArd Biesheuvel Select this in order to include support for the deprecated EFI 1949cc3fdda2SArd Biesheuvel handover protocol, which defines alternative entry points into the 1950cc3fdda2SArd Biesheuvel EFI stub. This is a practice that has no basis in the UEFI 1951cc3fdda2SArd Biesheuvel specification, and requires a priori knowledge on the part of the 1952cc3fdda2SArd Biesheuvel bootloader about Linux/x86 specific ways of passing the command line 1953cc3fdda2SArd Biesheuvel and initrd, and where in memory those assets may be loaded. 1954cc3fdda2SArd Biesheuvel 1955cc3fdda2SArd Biesheuvel If in doubt, say Y. Even though the corresponding support is not 1956cc3fdda2SArd Biesheuvel present in upstream GRUB or other bootloaders, most distros build 1957cc3fdda2SArd Biesheuvel GRUB with numerous downstream patches applied, and may rely on the 1958cc3fdda2SArd Biesheuvel handover protocol as as result. 1959cc3fdda2SArd Biesheuvel 19607d453eeeSMatt Flemingconfig EFI_MIXED 19617d453eeeSMatt Fleming bool "EFI mixed-mode support" 19627d453eeeSMatt Fleming depends on EFI_STUB && X86_64 1963a7f7f624SMasahiro Yamada help 19647d453eeeSMatt Fleming Enabling this feature allows a 64-bit kernel to be booted 19657d453eeeSMatt Fleming on a 32-bit firmware, provided that your CPU supports 64-bit 19667d453eeeSMatt Fleming mode. 19677d453eeeSMatt Fleming 19687d453eeeSMatt Fleming Note that it is not possible to boot a mixed-mode enabled 19697d453eeeSMatt Fleming kernel via the EFI boot stub - a bootloader that supports 19707d453eeeSMatt Fleming the EFI handover protocol must be used. 19717d453eeeSMatt Fleming 19727d453eeeSMatt Fleming If unsure, say N. 19737d453eeeSMatt Fleming 19744059ba65SArd Biesheuvelconfig EFI_FAKE_MEMMAP 19754059ba65SArd Biesheuvel bool "Enable EFI fake memory map" 19764059ba65SArd Biesheuvel depends on EFI 19774059ba65SArd Biesheuvel help 19784059ba65SArd Biesheuvel Saying Y here will enable "efi_fake_mem" boot option. By specifying 19794059ba65SArd Biesheuvel this parameter, you can add arbitrary attribute to specific memory 19804059ba65SArd Biesheuvel range by updating original (firmware provided) EFI memmap. This is 19814059ba65SArd Biesheuvel useful for debugging of EFI memmap related feature, e.g., Address 19824059ba65SArd Biesheuvel Range Mirroring feature. 19834059ba65SArd Biesheuvel 19844059ba65SArd Biesheuvelconfig EFI_MAX_FAKE_MEM 19854059ba65SArd Biesheuvel int "maximum allowable number of ranges in efi_fake_mem boot option" 19864059ba65SArd Biesheuvel depends on EFI_FAKE_MEMMAP 19874059ba65SArd Biesheuvel range 1 128 19884059ba65SArd Biesheuvel default 8 19894059ba65SArd Biesheuvel help 19904059ba65SArd Biesheuvel Maximum allowable number of ranges in efi_fake_mem boot option. 19914059ba65SArd Biesheuvel Ranges can be set up to this value using comma-separated list. 19924059ba65SArd Biesheuvel The default value is 8. 19934059ba65SArd Biesheuvel 19941fff234dSArd Biesheuvelconfig EFI_RUNTIME_MAP 19951fff234dSArd Biesheuvel bool "Export EFI runtime maps to sysfs" if EXPERT 19961fff234dSArd Biesheuvel depends on EFI 19971fff234dSArd Biesheuvel default KEXEC_CORE 19981fff234dSArd Biesheuvel help 19991fff234dSArd Biesheuvel Export EFI runtime memory regions to /sys/firmware/efi/runtime-map. 20001fff234dSArd Biesheuvel That memory map is required by the 2nd kernel to set up EFI virtual 20011fff234dSArd Biesheuvel mappings after kexec, but can also be used for debugging purposes. 20021fff234dSArd Biesheuvel 20031fff234dSArd Biesheuvel See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map. 20041fff234dSArd Biesheuvel 20058636a1f9SMasahiro Yamadasource "kernel/Kconfig.hz" 2006506f1d07SSam Ravnborg 2007506f1d07SSam Ravnborgconfig KEXEC 2008506f1d07SSam Ravnborg bool "kexec system call" 20092965faa5SDave Young select KEXEC_CORE 2010a7f7f624SMasahiro Yamada help 2011506f1d07SSam Ravnborg kexec is a system call that implements the ability to shutdown your 2012506f1d07SSam Ravnborg current kernel, and to start another kernel. It is like a reboot 2013506f1d07SSam Ravnborg but it is independent of the system firmware. And like a reboot 2014506f1d07SSam Ravnborg you can start any kernel with it, not just Linux. 2015506f1d07SSam Ravnborg 2016506f1d07SSam Ravnborg The name comes from the similarity to the exec system call. 2017506f1d07SSam Ravnborg 2018506f1d07SSam Ravnborg It is an ongoing process to be certain the hardware in a machine 2019506f1d07SSam Ravnborg is properly shutdown, so do not be surprised if this code does not 2020bf220695SGeert Uytterhoeven initially work for you. As of this writing the exact hardware 2021bf220695SGeert Uytterhoeven interface is strongly in flux, so no good recommendation can be 2022bf220695SGeert Uytterhoeven made. 2023506f1d07SSam Ravnborg 202474ca317cSVivek Goyalconfig KEXEC_FILE 202574ca317cSVivek Goyal bool "kexec file based system call" 20262965faa5SDave Young select KEXEC_CORE 2027b69a2afdSJonathan McDowell select HAVE_IMA_KEXEC if IMA 202874ca317cSVivek Goyal depends on X86_64 202974ca317cSVivek Goyal depends on CRYPTO=y 203074ca317cSVivek Goyal depends on CRYPTO_SHA256=y 2031a7f7f624SMasahiro Yamada help 203274ca317cSVivek Goyal This is new version of kexec system call. This system call is 203374ca317cSVivek Goyal file based and takes file descriptors as system call argument 203474ca317cSVivek Goyal for kernel and initramfs as opposed to list of segments as 203574ca317cSVivek Goyal accepted by previous system call. 203674ca317cSVivek Goyal 2037b799a09fSAKASHI Takahiroconfig ARCH_HAS_KEXEC_PURGATORY 2038b799a09fSAKASHI Takahiro def_bool KEXEC_FILE 2039b799a09fSAKASHI Takahiro 204099d5cadfSJiri Bohacconfig KEXEC_SIG 20418e7d8381SVivek Goyal bool "Verify kernel signature during kexec_file_load() syscall" 204274ca317cSVivek Goyal depends on KEXEC_FILE 2043a7f7f624SMasahiro Yamada help 204499d5cadfSJiri Bohac 204599d5cadfSJiri Bohac This option makes the kexec_file_load() syscall check for a valid 204699d5cadfSJiri Bohac signature of the kernel image. The image can still be loaded without 204799d5cadfSJiri Bohac a valid signature unless you also enable KEXEC_SIG_FORCE, though if 204899d5cadfSJiri Bohac there's a signature that we can check, then it must be valid. 204999d5cadfSJiri Bohac 205099d5cadfSJiri Bohac In addition to this option, you need to enable signature 205199d5cadfSJiri Bohac verification for the corresponding kernel image type being 205299d5cadfSJiri Bohac loaded in order for this to work. 205399d5cadfSJiri Bohac 205499d5cadfSJiri Bohacconfig KEXEC_SIG_FORCE 205599d5cadfSJiri Bohac bool "Require a valid signature in kexec_file_load() syscall" 205699d5cadfSJiri Bohac depends on KEXEC_SIG 2057a7f7f624SMasahiro Yamada help 20588e7d8381SVivek Goyal This option makes kernel signature verification mandatory for 2059d8eb8940SBorislav Petkov the kexec_file_load() syscall. 20608e7d8381SVivek Goyal 20618e7d8381SVivek Goyalconfig KEXEC_BZIMAGE_VERIFY_SIG 20628e7d8381SVivek Goyal bool "Enable bzImage signature verification support" 206399d5cadfSJiri Bohac depends on KEXEC_SIG 20648e7d8381SVivek Goyal depends on SIGNED_PE_FILE_VERIFICATION 20658e7d8381SVivek Goyal select SYSTEM_TRUSTED_KEYRING 2066a7f7f624SMasahiro Yamada help 20678e7d8381SVivek Goyal Enable bzImage signature verification support. 20688e7d8381SVivek Goyal 2069506f1d07SSam Ravnborgconfig CRASH_DUMP 207004b69447SPavel Machek bool "kernel crash dumps" 2071506f1d07SSam Ravnborg depends on X86_64 || (X86_32 && HIGHMEM) 2072a7f7f624SMasahiro Yamada help 2073506f1d07SSam Ravnborg Generate crash dump after being started by kexec. 2074506f1d07SSam Ravnborg This should be normally only set in special crash dump kernels 2075506f1d07SSam Ravnborg which are loaded in the main kernel with kexec-tools into 2076506f1d07SSam Ravnborg a specially reserved region and then later executed after 2077506f1d07SSam Ravnborg a crash by kdump/kexec. The crash dump kernel must be compiled 2078506f1d07SSam Ravnborg to a memory address not used by the main kernel or BIOS using 2079506f1d07SSam Ravnborg PHYSICAL_START, or it must be built as a relocatable image 2080506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y). 2081330d4810SMauro Carvalho Chehab For more details see Documentation/admin-guide/kdump/kdump.rst 2082506f1d07SSam Ravnborg 20833ab83521SHuang Yingconfig KEXEC_JUMP 20846ea30386SKees Cook bool "kexec jump" 2085fee7b0d8SHuang Ying depends on KEXEC && HIBERNATION 2086a7f7f624SMasahiro Yamada help 208789081d17SHuang Ying Jump between original kernel and kexeced kernel and invoke 208889081d17SHuang Ying code in physical address mode via KEXEC 20893ab83521SHuang Ying 2090506f1d07SSam Ravnborgconfig PHYSICAL_START 20916a108a14SDavid Rientjes hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2092ceefccc9SH. Peter Anvin default "0x1000000" 2093a7f7f624SMasahiro Yamada help 2094506f1d07SSam Ravnborg This gives the physical address where the kernel is loaded. 2095506f1d07SSam Ravnborg 2096506f1d07SSam Ravnborg If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2097506f1d07SSam Ravnborg bzImage will decompress itself to above physical address and 2098506f1d07SSam Ravnborg run from there. Otherwise, bzImage will run from the address where 2099506f1d07SSam Ravnborg it has been loaded by the boot loader and will ignore above physical 2100506f1d07SSam Ravnborg address. 2101506f1d07SSam Ravnborg 2102506f1d07SSam Ravnborg In normal kdump cases one does not have to set/change this option 2103506f1d07SSam Ravnborg as now bzImage can be compiled as a completely relocatable image 2104506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2105506f1d07SSam Ravnborg address. This option is mainly useful for the folks who don't want 2106506f1d07SSam Ravnborg to use a bzImage for capturing the crash dump and want to use a 2107506f1d07SSam Ravnborg vmlinux instead. vmlinux is not relocatable hence a kernel needs 2108506f1d07SSam Ravnborg to be specifically compiled to run from a specific memory area 2109506f1d07SSam Ravnborg (normally a reserved region) and this option comes handy. 2110506f1d07SSam Ravnborg 2111ceefccc9SH. Peter Anvin So if you are using bzImage for capturing the crash dump, 2112ceefccc9SH. Peter Anvin leave the value here unchanged to 0x1000000 and set 2113ceefccc9SH. Peter Anvin CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2114ceefccc9SH. Peter Anvin for capturing the crash dump change this value to start of 2115ceefccc9SH. Peter Anvin the reserved region. In other words, it can be set based on 2116ceefccc9SH. Peter Anvin the "X" value as specified in the "crashkernel=YM@XM" 2117ceefccc9SH. Peter Anvin command line boot parameter passed to the panic-ed 2118330d4810SMauro Carvalho Chehab kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2119ceefccc9SH. Peter Anvin for more details about crash dumps. 2120506f1d07SSam Ravnborg 2121506f1d07SSam Ravnborg Usage of bzImage for capturing the crash dump is recommended as 2122506f1d07SSam Ravnborg one does not have to build two kernels. Same kernel can be used 2123506f1d07SSam Ravnborg as production kernel and capture kernel. Above option should have 2124506f1d07SSam Ravnborg gone away after relocatable bzImage support is introduced. But it 2125506f1d07SSam Ravnborg is present because there are users out there who continue to use 2126506f1d07SSam Ravnborg vmlinux for dump capture. This option should go away down the 2127506f1d07SSam Ravnborg line. 2128506f1d07SSam Ravnborg 2129506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2130506f1d07SSam Ravnborg 2131506f1d07SSam Ravnborgconfig RELOCATABLE 213226717808SH. Peter Anvin bool "Build a relocatable kernel" 213326717808SH. Peter Anvin default y 2134a7f7f624SMasahiro Yamada help 2135506f1d07SSam Ravnborg This builds a kernel image that retains relocation information 2136506f1d07SSam Ravnborg so it can be loaded someplace besides the default 1MB. 2137506f1d07SSam Ravnborg The relocations tend to make the kernel binary about 10% larger, 2138506f1d07SSam Ravnborg but are discarded at runtime. 2139506f1d07SSam Ravnborg 2140506f1d07SSam Ravnborg One use is for the kexec on panic case where the recovery kernel 2141506f1d07SSam Ravnborg must live at a different physical address than the primary 2142506f1d07SSam Ravnborg kernel. 2143506f1d07SSam Ravnborg 2144506f1d07SSam Ravnborg Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2145506f1d07SSam Ravnborg it has been loaded at and the compile time physical address 21468ab3820fSKees Cook (CONFIG_PHYSICAL_START) is used as the minimum location. 2147506f1d07SSam Ravnborg 21488ab3820fSKees Cookconfig RANDOMIZE_BASE 2149e8581e3dSBaoquan He bool "Randomize the address of the kernel image (KASLR)" 21508ab3820fSKees Cook depends on RELOCATABLE 21516807c846SIngo Molnar default y 2152a7f7f624SMasahiro Yamada help 2153e8581e3dSBaoquan He In support of Kernel Address Space Layout Randomization (KASLR), 2154e8581e3dSBaoquan He this randomizes the physical address at which the kernel image 2155e8581e3dSBaoquan He is decompressed and the virtual address where the kernel 2156e8581e3dSBaoquan He image is mapped, as a security feature that deters exploit 2157e8581e3dSBaoquan He attempts relying on knowledge of the location of kernel 2158e8581e3dSBaoquan He code internals. 2159e8581e3dSBaoquan He 2160ed9f007eSKees Cook On 64-bit, the kernel physical and virtual addresses are 2161ed9f007eSKees Cook randomized separately. The physical address will be anywhere 2162ed9f007eSKees Cook between 16MB and the top of physical memory (up to 64TB). The 2163ed9f007eSKees Cook virtual address will be randomized from 16MB up to 1GB (9 bits 2164ed9f007eSKees Cook of entropy). Note that this also reduces the memory space 2165ed9f007eSKees Cook available to kernel modules from 1.5GB to 1GB. 2166ed9f007eSKees Cook 2167ed9f007eSKees Cook On 32-bit, the kernel physical and virtual addresses are 2168ed9f007eSKees Cook randomized together. They will be randomized from 16MB up to 2169ed9f007eSKees Cook 512MB (8 bits of entropy). 21708ab3820fSKees Cook 2171a653f356SKees Cook Entropy is generated using the RDRAND instruction if it is 2172e8581e3dSBaoquan He supported. If RDTSC is supported, its value is mixed into 2173e8581e3dSBaoquan He the entropy pool as well. If neither RDRAND nor RDTSC are 2174ed9f007eSKees Cook supported, then entropy is read from the i8254 timer. The 2175ed9f007eSKees Cook usable entropy is limited by the kernel being built using 2176ed9f007eSKees Cook 2GB addressing, and that PHYSICAL_ALIGN must be at a 2177ed9f007eSKees Cook minimum of 2MB. As a result, only 10 bits of entropy are 2178ed9f007eSKees Cook theoretically possible, but the implementations are further 2179ed9f007eSKees Cook limited due to memory layouts. 2180e8581e3dSBaoquan He 21816807c846SIngo Molnar If unsure, say Y. 2182da2b6fb9SKees Cook 21838ab3820fSKees Cook# Relocation on x86 needs some additional build support 2184845adf72SH. Peter Anvinconfig X86_NEED_RELOCS 2185845adf72SH. Peter Anvin def_bool y 21868ab3820fSKees Cook depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2187845adf72SH. Peter Anvin 2188506f1d07SSam Ravnborgconfig PHYSICAL_ALIGN 2189a0215061SKees Cook hex "Alignment value to which kernel should be aligned" 21908ab3820fSKees Cook default "0x200000" 2191a0215061SKees Cook range 0x2000 0x1000000 if X86_32 2192a0215061SKees Cook range 0x200000 0x1000000 if X86_64 2193a7f7f624SMasahiro Yamada help 2194506f1d07SSam Ravnborg This value puts the alignment restrictions on physical address 2195506f1d07SSam Ravnborg where kernel is loaded and run from. Kernel is compiled for an 2196506f1d07SSam Ravnborg address which meets above alignment restriction. 2197506f1d07SSam Ravnborg 2198506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2199506f1d07SSam Ravnborg CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2200506f1d07SSam Ravnborg address aligned to above value and run from there. 2201506f1d07SSam Ravnborg 2202506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2203506f1d07SSam Ravnborg CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2204506f1d07SSam Ravnborg load address and decompress itself to the address it has been 2205506f1d07SSam Ravnborg compiled for and run from there. The address for which kernel is 2206506f1d07SSam Ravnborg compiled already meets above alignment restrictions. Hence the 2207506f1d07SSam Ravnborg end result is that kernel runs from a physical address meeting 2208506f1d07SSam Ravnborg above alignment restrictions. 2209506f1d07SSam Ravnborg 2210a0215061SKees Cook On 32-bit this value must be a multiple of 0x2000. On 64-bit 2211a0215061SKees Cook this value must be a multiple of 0x200000. 2212a0215061SKees Cook 2213506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2214506f1d07SSam Ravnborg 2215eedb92abSKirill A. Shutemovconfig DYNAMIC_MEMORY_LAYOUT 2216eedb92abSKirill A. Shutemov bool 2217a7f7f624SMasahiro Yamada help 2218eedb92abSKirill A. Shutemov This option makes base addresses of vmalloc and vmemmap as well as 2219eedb92abSKirill A. Shutemov __PAGE_OFFSET movable during boot. 2220eedb92abSKirill A. Shutemov 22210483e1faSThomas Garnierconfig RANDOMIZE_MEMORY 22220483e1faSThomas Garnier bool "Randomize the kernel memory sections" 22230483e1faSThomas Garnier depends on X86_64 22240483e1faSThomas Garnier depends on RANDOMIZE_BASE 2225eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 22260483e1faSThomas Garnier default RANDOMIZE_BASE 2227a7f7f624SMasahiro Yamada help 22280483e1faSThomas Garnier Randomizes the base virtual address of kernel memory sections 22290483e1faSThomas Garnier (physical memory mapping, vmalloc & vmemmap). This security feature 22300483e1faSThomas Garnier makes exploits relying on predictable memory locations less reliable. 22310483e1faSThomas Garnier 22320483e1faSThomas Garnier The order of allocations remains unchanged. Entropy is generated in 22330483e1faSThomas Garnier the same way as RANDOMIZE_BASE. Current implementation in the optimal 22340483e1faSThomas Garnier configuration have in average 30,000 different possible virtual 22350483e1faSThomas Garnier addresses for each memory section. 22360483e1faSThomas Garnier 22376807c846SIngo Molnar If unsure, say Y. 22380483e1faSThomas Garnier 223990397a41SThomas Garnierconfig RANDOMIZE_MEMORY_PHYSICAL_PADDING 224090397a41SThomas Garnier hex "Physical memory mapping padding" if EXPERT 224190397a41SThomas Garnier depends on RANDOMIZE_MEMORY 224290397a41SThomas Garnier default "0xa" if MEMORY_HOTPLUG 224390397a41SThomas Garnier default "0x0" 224490397a41SThomas Garnier range 0x1 0x40 if MEMORY_HOTPLUG 224590397a41SThomas Garnier range 0x0 0x40 2246a7f7f624SMasahiro Yamada help 224790397a41SThomas Garnier Define the padding in terabytes added to the existing physical 224890397a41SThomas Garnier memory size during kernel memory randomization. It is useful 224990397a41SThomas Garnier for memory hotplug support but reduces the entropy available for 225090397a41SThomas Garnier address randomization. 225190397a41SThomas Garnier 225290397a41SThomas Garnier If unsure, leave at the default value. 225390397a41SThomas Garnier 22546449dcb0SKirill A. Shutemovconfig ADDRESS_MASKING 22556449dcb0SKirill A. Shutemov bool "Linear Address Masking support" 22566449dcb0SKirill A. Shutemov depends on X86_64 22576449dcb0SKirill A. Shutemov help 22586449dcb0SKirill A. Shutemov Linear Address Masking (LAM) modifies the checking that is applied 22596449dcb0SKirill A. Shutemov to 64-bit linear addresses, allowing software to use of the 22606449dcb0SKirill A. Shutemov untranslated address bits for metadata. 22616449dcb0SKirill A. Shutemov 22626449dcb0SKirill A. Shutemov The capability can be used for efficient address sanitizers (ASAN) 22636449dcb0SKirill A. Shutemov implementation and for optimizations in JITs. 22646449dcb0SKirill A. Shutemov 2265506f1d07SSam Ravnborgconfig HOTPLUG_CPU 2266bebd024eSThomas Gleixner def_bool y 226740b31360SStephen Rothwell depends on SMP 2268506f1d07SSam Ravnborg 2269506f1d07SSam Ravnborgconfig COMPAT_VDSO 2270b0b49f26SAndy Lutomirski def_bool n 2271b0b49f26SAndy Lutomirski prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2272953fee1dSIngo Molnar depends on COMPAT_32 2273a7f7f624SMasahiro Yamada help 2274b0b49f26SAndy Lutomirski Certain buggy versions of glibc will crash if they are 2275b0b49f26SAndy Lutomirski presented with a 32-bit vDSO that is not mapped at the address 2276b0b49f26SAndy Lutomirski indicated in its segment table. 2277e84446deSRandy Dunlap 2278b0b49f26SAndy Lutomirski The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2279b0b49f26SAndy Lutomirski and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2280b0b49f26SAndy Lutomirski 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2281b0b49f26SAndy Lutomirski the only released version with the bug, but OpenSUSE 9 2282b0b49f26SAndy Lutomirski contains a buggy "glibc 2.3.2". 2283506f1d07SSam Ravnborg 2284b0b49f26SAndy Lutomirski The symptom of the bug is that everything crashes on startup, saying: 2285b0b49f26SAndy Lutomirski dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2286b0b49f26SAndy Lutomirski 2287b0b49f26SAndy Lutomirski Saying Y here changes the default value of the vdso32 boot 2288b0b49f26SAndy Lutomirski option from 1 to 0, which turns off the 32-bit vDSO entirely. 2289b0b49f26SAndy Lutomirski This works around the glibc bug but hurts performance. 2290b0b49f26SAndy Lutomirski 2291b0b49f26SAndy Lutomirski If unsure, say N: if you are compiling your own kernel, you 2292b0b49f26SAndy Lutomirski are unlikely to be using a buggy version of glibc. 2293506f1d07SSam Ravnborg 22943dc33bd3SKees Cookchoice 22953dc33bd3SKees Cook prompt "vsyscall table for legacy applications" 22963dc33bd3SKees Cook depends on X86_64 2297625b7b7fSAndy Lutomirski default LEGACY_VSYSCALL_XONLY 22983dc33bd3SKees Cook help 22993dc33bd3SKees Cook Legacy user code that does not know how to find the vDSO expects 23003dc33bd3SKees Cook to be able to issue three syscalls by calling fixed addresses in 23013dc33bd3SKees Cook kernel space. Since this location is not randomized with ASLR, 23023dc33bd3SKees Cook it can be used to assist security vulnerability exploitation. 23033dc33bd3SKees Cook 23043dc33bd3SKees Cook This setting can be changed at boot time via the kernel command 2305bf00745eSAndy Lutomirski line parameter vsyscall=[emulate|xonly|none]. Emulate mode 2306bf00745eSAndy Lutomirski is deprecated and can only be enabled using the kernel command 2307bf00745eSAndy Lutomirski line. 23083dc33bd3SKees Cook 23093dc33bd3SKees Cook On a system with recent enough glibc (2.14 or newer) and no 23103dc33bd3SKees Cook static binaries, you can say None without a performance penalty 23113dc33bd3SKees Cook to improve security. 23123dc33bd3SKees Cook 2313bd49e16eSAndy Lutomirski If unsure, select "Emulate execution only". 23143dc33bd3SKees Cook 2315bd49e16eSAndy Lutomirski config LEGACY_VSYSCALL_XONLY 2316bd49e16eSAndy Lutomirski bool "Emulate execution only" 2317bd49e16eSAndy Lutomirski help 2318bd49e16eSAndy Lutomirski The kernel traps and emulates calls into the fixed vsyscall 2319bd49e16eSAndy Lutomirski address mapping and does not allow reads. This 2320bd49e16eSAndy Lutomirski configuration is recommended when userspace might use the 2321bd49e16eSAndy Lutomirski legacy vsyscall area but support for legacy binary 2322bd49e16eSAndy Lutomirski instrumentation of legacy code is not needed. It mitigates 2323bd49e16eSAndy Lutomirski certain uses of the vsyscall area as an ASLR-bypassing 2324bd49e16eSAndy Lutomirski buffer. 23253dc33bd3SKees Cook 23263dc33bd3SKees Cook config LEGACY_VSYSCALL_NONE 23273dc33bd3SKees Cook bool "None" 23283dc33bd3SKees Cook help 23293dc33bd3SKees Cook There will be no vsyscall mapping at all. This will 23303dc33bd3SKees Cook eliminate any risk of ASLR bypass due to the vsyscall 23313dc33bd3SKees Cook fixed address mapping. Attempts to use the vsyscalls 23323dc33bd3SKees Cook will be reported to dmesg, so that either old or 23333dc33bd3SKees Cook malicious userspace programs can be identified. 23343dc33bd3SKees Cook 23353dc33bd3SKees Cookendchoice 23363dc33bd3SKees Cook 2337516cbf37STim Birdconfig CMDLINE_BOOL 2338516cbf37STim Bird bool "Built-in kernel command line" 2339a7f7f624SMasahiro Yamada help 2340516cbf37STim Bird Allow for specifying boot arguments to the kernel at 2341516cbf37STim Bird build time. On some systems (e.g. embedded ones), it is 2342516cbf37STim Bird necessary or convenient to provide some or all of the 2343516cbf37STim Bird kernel boot arguments with the kernel itself (that is, 2344516cbf37STim Bird to not rely on the boot loader to provide them.) 2345516cbf37STim Bird 2346516cbf37STim Bird To compile command line arguments into the kernel, 2347516cbf37STim Bird set this option to 'Y', then fill in the 234869711ca1SSébastien Hinderer boot arguments in CONFIG_CMDLINE. 2349516cbf37STim Bird 2350516cbf37STim Bird Systems with fully functional boot loaders (i.e. non-embedded) 2351516cbf37STim Bird should leave this option set to 'N'. 2352516cbf37STim Bird 2353516cbf37STim Birdconfig CMDLINE 2354516cbf37STim Bird string "Built-in kernel command string" 2355516cbf37STim Bird depends on CMDLINE_BOOL 2356516cbf37STim Bird default "" 2357a7f7f624SMasahiro Yamada help 2358516cbf37STim Bird Enter arguments here that should be compiled into the kernel 2359516cbf37STim Bird image and used at boot time. If the boot loader provides a 2360516cbf37STim Bird command line at boot time, it is appended to this string to 2361516cbf37STim Bird form the full kernel command line, when the system boots. 2362516cbf37STim Bird 2363516cbf37STim Bird However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2364516cbf37STim Bird change this behavior. 2365516cbf37STim Bird 2366516cbf37STim Bird In most cases, the command line (whether built-in or provided 2367516cbf37STim Bird by the boot loader) should specify the device for the root 2368516cbf37STim Bird file system. 2369516cbf37STim Bird 2370516cbf37STim Birdconfig CMDLINE_OVERRIDE 2371516cbf37STim Bird bool "Built-in command line overrides boot loader arguments" 2372645e6466SAnders Roxell depends on CMDLINE_BOOL && CMDLINE != "" 2373a7f7f624SMasahiro Yamada help 2374516cbf37STim Bird Set this option to 'Y' to have the kernel ignore the boot loader 2375516cbf37STim Bird command line, and use ONLY the built-in command line. 2376516cbf37STim Bird 2377516cbf37STim Bird This is used to work around broken boot loaders. This should 2378516cbf37STim Bird be set to 'N' under normal conditions. 2379516cbf37STim Bird 2380a5b9e5a2SAndy Lutomirskiconfig MODIFY_LDT_SYSCALL 2381a5b9e5a2SAndy Lutomirski bool "Enable the LDT (local descriptor table)" if EXPERT 2382a5b9e5a2SAndy Lutomirski default y 2383a7f7f624SMasahiro Yamada help 2384a5b9e5a2SAndy Lutomirski Linux can allow user programs to install a per-process x86 2385a5b9e5a2SAndy Lutomirski Local Descriptor Table (LDT) using the modify_ldt(2) system 2386a5b9e5a2SAndy Lutomirski call. This is required to run 16-bit or segmented code such as 2387a5b9e5a2SAndy Lutomirski DOSEMU or some Wine programs. It is also used by some very old 2388a5b9e5a2SAndy Lutomirski threading libraries. 2389a5b9e5a2SAndy Lutomirski 2390a5b9e5a2SAndy Lutomirski Enabling this feature adds a small amount of overhead to 2391a5b9e5a2SAndy Lutomirski context switches and increases the low-level kernel attack 2392a5b9e5a2SAndy Lutomirski surface. Disabling it removes the modify_ldt(2) system call. 2393a5b9e5a2SAndy Lutomirski 2394a5b9e5a2SAndy Lutomirski Saying 'N' here may make sense for embedded or server kernels. 2395a5b9e5a2SAndy Lutomirski 23963aac3ebeSThomas Gleixnerconfig STRICT_SIGALTSTACK_SIZE 23973aac3ebeSThomas Gleixner bool "Enforce strict size checking for sigaltstack" 23983aac3ebeSThomas Gleixner depends on DYNAMIC_SIGFRAME 23993aac3ebeSThomas Gleixner help 24003aac3ebeSThomas Gleixner For historical reasons MINSIGSTKSZ is a constant which became 24013aac3ebeSThomas Gleixner already too small with AVX512 support. Add a mechanism to 24023aac3ebeSThomas Gleixner enforce strict checking of the sigaltstack size against the 24033aac3ebeSThomas Gleixner real size of the FPU frame. This option enables the check 24043aac3ebeSThomas Gleixner by default. It can also be controlled via the kernel command 24053aac3ebeSThomas Gleixner line option 'strict_sas_size' independent of this config 24063aac3ebeSThomas Gleixner switch. Enabling it might break existing applications which 24073aac3ebeSThomas Gleixner allocate a too small sigaltstack but 'work' because they 24083aac3ebeSThomas Gleixner never get a signal delivered. 24093aac3ebeSThomas Gleixner 24103aac3ebeSThomas Gleixner Say 'N' unless you want to really enforce this check. 24113aac3ebeSThomas Gleixner 2412b700e7f0SSeth Jenningssource "kernel/livepatch/Kconfig" 2413b700e7f0SSeth Jennings 2414506f1d07SSam Ravnborgendmenu 2415506f1d07SSam Ravnborg 2416f43b9876SPeter Zijlstraconfig CC_HAS_SLS 2417f43b9876SPeter Zijlstra def_bool $(cc-option,-mharden-sls=all) 2418f43b9876SPeter Zijlstra 2419f43b9876SPeter Zijlstraconfig CC_HAS_RETURN_THUNK 2420f43b9876SPeter Zijlstra def_bool $(cc-option,-mfunction-return=thunk-extern) 2421f43b9876SPeter Zijlstra 2422bea75b33SThomas Gleixnerconfig CC_HAS_ENTRY_PADDING 2423bea75b33SThomas Gleixner def_bool $(cc-option,-fpatchable-function-entry=16,16) 2424bea75b33SThomas Gleixner 2425bea75b33SThomas Gleixnerconfig FUNCTION_PADDING_CFI 2426bea75b33SThomas Gleixner int 2427bea75b33SThomas Gleixner default 59 if FUNCTION_ALIGNMENT_64B 2428bea75b33SThomas Gleixner default 27 if FUNCTION_ALIGNMENT_32B 2429bea75b33SThomas Gleixner default 11 if FUNCTION_ALIGNMENT_16B 2430bea75b33SThomas Gleixner default 3 if FUNCTION_ALIGNMENT_8B 2431bea75b33SThomas Gleixner default 0 2432bea75b33SThomas Gleixner 2433bea75b33SThomas Gleixner# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG 2434bea75b33SThomas Gleixner# except Kconfig can't do arithmetic :/ 2435bea75b33SThomas Gleixnerconfig FUNCTION_PADDING_BYTES 2436bea75b33SThomas Gleixner int 2437bea75b33SThomas Gleixner default FUNCTION_PADDING_CFI if CFI_CLANG 2438bea75b33SThomas Gleixner default FUNCTION_ALIGNMENT 2439bea75b33SThomas Gleixner 2440931ab636SPeter Zijlstraconfig CALL_PADDING 2441931ab636SPeter Zijlstra def_bool n 2442931ab636SPeter Zijlstra depends on CC_HAS_ENTRY_PADDING && OBJTOOL 2443931ab636SPeter Zijlstra select FUNCTION_ALIGNMENT_16B 2444931ab636SPeter Zijlstra 2445931ab636SPeter Zijlstraconfig FINEIBT 2446931ab636SPeter Zijlstra def_bool y 2447931ab636SPeter Zijlstra depends on X86_KERNEL_IBT && CFI_CLANG && RETPOLINE 2448931ab636SPeter Zijlstra select CALL_PADDING 2449931ab636SPeter Zijlstra 24508f7c0d8bSThomas Gleixnerconfig HAVE_CALL_THUNKS 24518f7c0d8bSThomas Gleixner def_bool y 2452bea75b33SThomas Gleixner depends on CC_HAS_ENTRY_PADDING && RETHUNK && OBJTOOL 24538f7c0d8bSThomas Gleixner 24548f7c0d8bSThomas Gleixnerconfig CALL_THUNKS 24558f7c0d8bSThomas Gleixner def_bool n 2456931ab636SPeter Zijlstra select CALL_PADDING 24578f7c0d8bSThomas Gleixner 2458b341b20dSPeter Zijlstraconfig PREFIX_SYMBOLS 2459b341b20dSPeter Zijlstra def_bool y 2460931ab636SPeter Zijlstra depends on CALL_PADDING && !CFI_CLANG 2461b341b20dSPeter Zijlstra 2462f43b9876SPeter Zijlstramenuconfig SPECULATION_MITIGATIONS 2463f43b9876SPeter Zijlstra bool "Mitigations for speculative execution vulnerabilities" 2464f43b9876SPeter Zijlstra default y 2465f43b9876SPeter Zijlstra help 2466f43b9876SPeter Zijlstra Say Y here to enable options which enable mitigations for 2467f43b9876SPeter Zijlstra speculative execution hardware vulnerabilities. 2468f43b9876SPeter Zijlstra 2469f43b9876SPeter Zijlstra If you say N, all mitigations will be disabled. You really 2470f43b9876SPeter Zijlstra should know what you are doing to say so. 2471f43b9876SPeter Zijlstra 2472f43b9876SPeter Zijlstraif SPECULATION_MITIGATIONS 2473f43b9876SPeter Zijlstra 2474f43b9876SPeter Zijlstraconfig PAGE_TABLE_ISOLATION 2475f43b9876SPeter Zijlstra bool "Remove the kernel mapping in user mode" 2476f43b9876SPeter Zijlstra default y 2477f43b9876SPeter Zijlstra depends on (X86_64 || X86_PAE) 2478f43b9876SPeter Zijlstra help 2479f43b9876SPeter Zijlstra This feature reduces the number of hardware side channels by 2480f43b9876SPeter Zijlstra ensuring that the majority of kernel addresses are not mapped 2481f43b9876SPeter Zijlstra into userspace. 2482f43b9876SPeter Zijlstra 2483ff61f079SJonathan Corbet See Documentation/arch/x86/pti.rst for more details. 2484f43b9876SPeter Zijlstra 2485f43b9876SPeter Zijlstraconfig RETPOLINE 2486f43b9876SPeter Zijlstra bool "Avoid speculative indirect branches in kernel" 2487f43b9876SPeter Zijlstra select OBJTOOL if HAVE_OBJTOOL 2488f43b9876SPeter Zijlstra default y 2489f43b9876SPeter Zijlstra help 2490f43b9876SPeter Zijlstra Compile kernel with the retpoline compiler options to guard against 2491f43b9876SPeter Zijlstra kernel-to-user data leaks by avoiding speculative indirect 2492f43b9876SPeter Zijlstra branches. Requires a compiler with -mindirect-branch=thunk-extern 2493f43b9876SPeter Zijlstra support for full protection. The kernel may run slower. 2494f43b9876SPeter Zijlstra 2495f43b9876SPeter Zijlstraconfig RETHUNK 2496f43b9876SPeter Zijlstra bool "Enable return-thunks" 2497f43b9876SPeter Zijlstra depends on RETPOLINE && CC_HAS_RETURN_THUNK 2498f43b9876SPeter Zijlstra select OBJTOOL if HAVE_OBJTOOL 2499b648ab48SBen Hutchings default y if X86_64 2500f43b9876SPeter Zijlstra help 2501f43b9876SPeter Zijlstra Compile the kernel with the return-thunks compiler option to guard 2502f43b9876SPeter Zijlstra against kernel-to-user data leaks by avoiding return speculation. 2503f43b9876SPeter Zijlstra Requires a compiler with -mfunction-return=thunk-extern 2504f43b9876SPeter Zijlstra support for full protection. The kernel may run slower. 2505f43b9876SPeter Zijlstra 2506f43b9876SPeter Zijlstraconfig CPU_UNRET_ENTRY 2507f43b9876SPeter Zijlstra bool "Enable UNRET on kernel entry" 2508b648ab48SBen Hutchings depends on CPU_SUP_AMD && RETHUNK && X86_64 2509f43b9876SPeter Zijlstra default y 2510f43b9876SPeter Zijlstra help 2511f43b9876SPeter Zijlstra Compile the kernel with support for the retbleed=unret mitigation. 2512f43b9876SPeter Zijlstra 251380e4c1cdSThomas Gleixnerconfig CALL_DEPTH_TRACKING 251480e4c1cdSThomas Gleixner bool "Mitigate RSB underflow with call depth tracking" 251580e4c1cdSThomas Gleixner depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS 251680e4c1cdSThomas Gleixner select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 251780e4c1cdSThomas Gleixner select CALL_THUNKS 251880e4c1cdSThomas Gleixner default y 251980e4c1cdSThomas Gleixner help 252080e4c1cdSThomas Gleixner Compile the kernel with call depth tracking to mitigate the Intel 252180e4c1cdSThomas Gleixner SKL Return-Speculation-Buffer (RSB) underflow issue. The 252280e4c1cdSThomas Gleixner mitigation is off by default and needs to be enabled on the 252380e4c1cdSThomas Gleixner kernel command line via the retbleed=stuff option. For 252480e4c1cdSThomas Gleixner non-affected systems the overhead of this option is marginal as 252580e4c1cdSThomas Gleixner the call depth tracking is using run-time generated call thunks 252680e4c1cdSThomas Gleixner in a compiler generated padding area and call patching. This 252780e4c1cdSThomas Gleixner increases text size by ~5%. For non affected systems this space 252880e4c1cdSThomas Gleixner is unused. On affected SKL systems this results in a significant 252980e4c1cdSThomas Gleixner performance gain over the IBRS mitigation. 253080e4c1cdSThomas Gleixner 2531e81dc127SThomas Gleixnerconfig CALL_THUNKS_DEBUG 2532e81dc127SThomas Gleixner bool "Enable call thunks and call depth tracking debugging" 2533e81dc127SThomas Gleixner depends on CALL_DEPTH_TRACKING 2534e81dc127SThomas Gleixner select FUNCTION_ALIGNMENT_32B 2535e81dc127SThomas Gleixner default n 2536e81dc127SThomas Gleixner help 2537e81dc127SThomas Gleixner Enable call/ret counters for imbalance detection and build in 2538e81dc127SThomas Gleixner a noisy dmesg about callthunks generation and call patching for 2539e81dc127SThomas Gleixner trouble shooting. The debug prints need to be enabled on the 2540e81dc127SThomas Gleixner kernel command line with 'debug-callthunks'. 254154628de6SRandy Dunlap Only enable this when you are debugging call thunks as this 254254628de6SRandy Dunlap creates a noticeable runtime overhead. If unsure say N. 254380e4c1cdSThomas Gleixner 2544f43b9876SPeter Zijlstraconfig CPU_IBPB_ENTRY 2545f43b9876SPeter Zijlstra bool "Enable IBPB on kernel entry" 2546b648ab48SBen Hutchings depends on CPU_SUP_AMD && X86_64 2547f43b9876SPeter Zijlstra default y 2548f43b9876SPeter Zijlstra help 2549f43b9876SPeter Zijlstra Compile the kernel with support for the retbleed=ibpb mitigation. 2550f43b9876SPeter Zijlstra 2551f43b9876SPeter Zijlstraconfig CPU_IBRS_ENTRY 2552f43b9876SPeter Zijlstra bool "Enable IBRS on kernel entry" 2553b648ab48SBen Hutchings depends on CPU_SUP_INTEL && X86_64 2554f43b9876SPeter Zijlstra default y 2555f43b9876SPeter Zijlstra help 2556f43b9876SPeter Zijlstra Compile the kernel with support for the spectre_v2=ibrs mitigation. 2557f43b9876SPeter Zijlstra This mitigates both spectre_v2 and retbleed at great cost to 2558f43b9876SPeter Zijlstra performance. 2559f43b9876SPeter Zijlstra 2560f43b9876SPeter Zijlstraconfig SLS 2561f43b9876SPeter Zijlstra bool "Mitigate Straight-Line-Speculation" 2562f43b9876SPeter Zijlstra depends on CC_HAS_SLS && X86_64 2563f43b9876SPeter Zijlstra select OBJTOOL if HAVE_OBJTOOL 2564f43b9876SPeter Zijlstra default n 2565f43b9876SPeter Zijlstra help 2566f43b9876SPeter Zijlstra Compile the kernel with straight-line-speculation options to guard 2567f43b9876SPeter Zijlstra against straight line speculation. The kernel image might be slightly 2568f43b9876SPeter Zijlstra larger. 2569f43b9876SPeter Zijlstra 2570f43b9876SPeter Zijlstraendif 2571f43b9876SPeter Zijlstra 25723072e413SMichal Hockoconfig ARCH_HAS_ADD_PAGES 25733072e413SMichal Hocko def_bool y 25745c11f00bSDavid Hildenbrand depends on ARCH_ENABLE_MEMORY_HOTPLUG 25753072e413SMichal Hocko 2576f91ef222SOscar Salvadorconfig ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 2577f91ef222SOscar Salvador def_bool y 2578f91ef222SOscar Salvador 2579da85f865SBjorn Helgaasmenu "Power management and ACPI options" 2580e279b6c1SSam Ravnborg 2581e279b6c1SSam Ravnborgconfig ARCH_HIBERNATION_HEADER 25823c2362e6SHarvey Harrison def_bool y 258344556530SZhimin Gu depends on HIBERNATION 2584e279b6c1SSam Ravnborg 2585e279b6c1SSam Ravnborgsource "kernel/power/Kconfig" 2586e279b6c1SSam Ravnborg 2587e279b6c1SSam Ravnborgsource "drivers/acpi/Kconfig" 2588e279b6c1SSam Ravnborg 2589a6b68076SAndi Kleenconfig X86_APM_BOOT 25906fc108a0SJan Beulich def_bool y 2591282e5aabSPaul Bolle depends on APM 2592a6b68076SAndi Kleen 2593e279b6c1SSam Ravnborgmenuconfig APM 2594e279b6c1SSam Ravnborg tristate "APM (Advanced Power Management) BIOS support" 2595efefa6f6SIngo Molnar depends on X86_32 && PM_SLEEP 2596a7f7f624SMasahiro Yamada help 2597e279b6c1SSam Ravnborg APM is a BIOS specification for saving power using several different 2598e279b6c1SSam Ravnborg techniques. This is mostly useful for battery powered laptops with 2599e279b6c1SSam Ravnborg APM compliant BIOSes. If you say Y here, the system time will be 2600e279b6c1SSam Ravnborg reset after a RESUME operation, the /proc/apm device will provide 2601e279b6c1SSam Ravnborg battery status information, and user-space programs will receive 2602e279b6c1SSam Ravnborg notification of APM "events" (e.g. battery status change). 2603e279b6c1SSam Ravnborg 2604e279b6c1SSam Ravnborg If you select "Y" here, you can disable actual use of the APM 2605e279b6c1SSam Ravnborg BIOS by passing the "apm=off" option to the kernel at boot time. 2606e279b6c1SSam Ravnborg 2607e279b6c1SSam Ravnborg Note that the APM support is almost completely disabled for 2608e279b6c1SSam Ravnborg machines with more than one CPU. 2609e279b6c1SSam Ravnborg 2610e279b6c1SSam Ravnborg In order to use APM, you will need supporting software. For location 2611151f4e2bSMauro Carvalho Chehab and more information, read <file:Documentation/power/apm-acpi.rst> 26122dc98fd3SMichael Witten and the Battery Powered Linux mini-HOWTO, available from 2613e279b6c1SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 2614e279b6c1SSam Ravnborg 2615e279b6c1SSam Ravnborg This driver does not spin down disk drives (see the hdparm(8) 2616e279b6c1SSam Ravnborg manpage ("man 8 hdparm") for that), and it doesn't turn off 2617e279b6c1SSam Ravnborg VESA-compliant "green" monitors. 2618e279b6c1SSam Ravnborg 2619e279b6c1SSam Ravnborg This driver does not support the TI 4000M TravelMate and the ACER 2620e279b6c1SSam Ravnborg 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2621e279b6c1SSam Ravnborg desktop machines also don't have compliant BIOSes, and this driver 2622e279b6c1SSam Ravnborg may cause those machines to panic during the boot phase. 2623e279b6c1SSam Ravnborg 2624e279b6c1SSam Ravnborg Generally, if you don't have a battery in your machine, there isn't 2625e279b6c1SSam Ravnborg much point in using this driver and you should say N. If you get 2626e279b6c1SSam Ravnborg random kernel OOPSes or reboots that don't seem to be related to 2627e279b6c1SSam Ravnborg anything, try disabling/enabling this option (or disabling/enabling 2628e279b6c1SSam Ravnborg APM in your BIOS). 2629e279b6c1SSam Ravnborg 2630e279b6c1SSam Ravnborg Some other things you should try when experiencing seemingly random, 2631e279b6c1SSam Ravnborg "weird" problems: 2632e279b6c1SSam Ravnborg 2633e279b6c1SSam Ravnborg 1) make sure that you have enough swap space and that it is 2634e279b6c1SSam Ravnborg enabled. 26357987448fSStephen Kitt 2) pass the "idle=poll" option to the kernel 2636e279b6c1SSam Ravnborg 3) switch on floating point emulation in the kernel and pass 2637e279b6c1SSam Ravnborg the "no387" option to the kernel 2638e279b6c1SSam Ravnborg 4) pass the "floppy=nodma" option to the kernel 2639e279b6c1SSam Ravnborg 5) pass the "mem=4M" option to the kernel (thereby disabling 2640e279b6c1SSam Ravnborg all but the first 4 MB of RAM) 2641e279b6c1SSam Ravnborg 6) make sure that the CPU is not over clocked. 2642e279b6c1SSam Ravnborg 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2643e279b6c1SSam Ravnborg 8) disable the cache from your BIOS settings 2644e279b6c1SSam Ravnborg 9) install a fan for the video card or exchange video RAM 2645e279b6c1SSam Ravnborg 10) install a better fan for the CPU 2646e279b6c1SSam Ravnborg 11) exchange RAM chips 2647e279b6c1SSam Ravnborg 12) exchange the motherboard. 2648e279b6c1SSam Ravnborg 2649e279b6c1SSam Ravnborg To compile this driver as a module, choose M here: the 2650e279b6c1SSam Ravnborg module will be called apm. 2651e279b6c1SSam Ravnborg 2652e279b6c1SSam Ravnborgif APM 2653e279b6c1SSam Ravnborg 2654e279b6c1SSam Ravnborgconfig APM_IGNORE_USER_SUSPEND 2655e279b6c1SSam Ravnborg bool "Ignore USER SUSPEND" 2656a7f7f624SMasahiro Yamada help 2657e279b6c1SSam Ravnborg This option will ignore USER SUSPEND requests. On machines with a 2658e279b6c1SSam Ravnborg compliant APM BIOS, you want to say N. However, on the NEC Versa M 2659e279b6c1SSam Ravnborg series notebooks, it is necessary to say Y because of a BIOS bug. 2660e279b6c1SSam Ravnborg 2661e279b6c1SSam Ravnborgconfig APM_DO_ENABLE 2662e279b6c1SSam Ravnborg bool "Enable PM at boot time" 2663a7f7f624SMasahiro Yamada help 2664e279b6c1SSam Ravnborg Enable APM features at boot time. From page 36 of the APM BIOS 2665e279b6c1SSam Ravnborg specification: "When disabled, the APM BIOS does not automatically 2666e279b6c1SSam Ravnborg power manage devices, enter the Standby State, enter the Suspend 2667e279b6c1SSam Ravnborg State, or take power saving steps in response to CPU Idle calls." 2668e279b6c1SSam Ravnborg This driver will make CPU Idle calls when Linux is idle (unless this 2669e279b6c1SSam Ravnborg feature is turned off -- see "Do CPU IDLE calls", below). This 2670e279b6c1SSam Ravnborg should always save battery power, but more complicated APM features 2671e279b6c1SSam Ravnborg will be dependent on your BIOS implementation. You may need to turn 2672e279b6c1SSam Ravnborg this option off if your computer hangs at boot time when using APM 2673e279b6c1SSam Ravnborg support, or if it beeps continuously instead of suspending. Turn 2674e279b6c1SSam Ravnborg this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2675e279b6c1SSam Ravnborg T400CDT. This is off by default since most machines do fine without 2676e279b6c1SSam Ravnborg this feature. 2677e279b6c1SSam Ravnborg 2678e279b6c1SSam Ravnborgconfig APM_CPU_IDLE 2679dd8af076SLen Brown depends on CPU_IDLE 2680e279b6c1SSam Ravnborg bool "Make CPU Idle calls when idle" 2681a7f7f624SMasahiro Yamada help 2682e279b6c1SSam Ravnborg Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2683e279b6c1SSam Ravnborg On some machines, this can activate improved power savings, such as 2684e279b6c1SSam Ravnborg a slowed CPU clock rate, when the machine is idle. These idle calls 2685e279b6c1SSam Ravnborg are made after the idle loop has run for some length of time (e.g., 2686e279b6c1SSam Ravnborg 333 mS). On some machines, this will cause a hang at boot time or 2687e279b6c1SSam Ravnborg whenever the CPU becomes idle. (On machines with more than one CPU, 2688e279b6c1SSam Ravnborg this option does nothing.) 2689e279b6c1SSam Ravnborg 2690e279b6c1SSam Ravnborgconfig APM_DISPLAY_BLANK 2691e279b6c1SSam Ravnborg bool "Enable console blanking using APM" 2692a7f7f624SMasahiro Yamada help 2693e279b6c1SSam Ravnborg Enable console blanking using the APM. Some laptops can use this to 2694e279b6c1SSam Ravnborg turn off the LCD backlight when the screen blanker of the Linux 2695e279b6c1SSam Ravnborg virtual console blanks the screen. Note that this is only used by 2696e279b6c1SSam Ravnborg the virtual console screen blanker, and won't turn off the backlight 2697e279b6c1SSam Ravnborg when using the X Window system. This also doesn't have anything to 2698e279b6c1SSam Ravnborg do with your VESA-compliant power-saving monitor. Further, this 2699e279b6c1SSam Ravnborg option doesn't work for all laptops -- it might not turn off your 2700e279b6c1SSam Ravnborg backlight at all, or it might print a lot of errors to the console, 2701e279b6c1SSam Ravnborg especially if you are using gpm. 2702e279b6c1SSam Ravnborg 2703e279b6c1SSam Ravnborgconfig APM_ALLOW_INTS 2704e279b6c1SSam Ravnborg bool "Allow interrupts during APM BIOS calls" 2705a7f7f624SMasahiro Yamada help 2706e279b6c1SSam Ravnborg Normally we disable external interrupts while we are making calls to 2707e279b6c1SSam Ravnborg the APM BIOS as a measure to lessen the effects of a badly behaving 2708e279b6c1SSam Ravnborg BIOS implementation. The BIOS should reenable interrupts if it 2709e279b6c1SSam Ravnborg needs to. Unfortunately, some BIOSes do not -- especially those in 2710e279b6c1SSam Ravnborg many of the newer IBM Thinkpads. If you experience hangs when you 2711e279b6c1SSam Ravnborg suspend, try setting this to Y. Otherwise, say N. 2712e279b6c1SSam Ravnborg 2713e279b6c1SSam Ravnborgendif # APM 2714e279b6c1SSam Ravnborg 2715bb0a56ecSDave Jonessource "drivers/cpufreq/Kconfig" 2716e279b6c1SSam Ravnborg 2717e279b6c1SSam Ravnborgsource "drivers/cpuidle/Kconfig" 2718e279b6c1SSam Ravnborg 271927471fdbSAndy Henroidsource "drivers/idle/Kconfig" 272027471fdbSAndy Henroid 2721e279b6c1SSam Ravnborgendmenu 2722e279b6c1SSam Ravnborg 2723e279b6c1SSam Ravnborgmenu "Bus options (PCI etc.)" 2724e279b6c1SSam Ravnborg 2725e279b6c1SSam Ravnborgchoice 2726e279b6c1SSam Ravnborg prompt "PCI access mode" 2727efefa6f6SIngo Molnar depends on X86_32 && PCI 2728e279b6c1SSam Ravnborg default PCI_GOANY 2729a7f7f624SMasahiro Yamada help 2730e279b6c1SSam Ravnborg On PCI systems, the BIOS can be used to detect the PCI devices and 2731e279b6c1SSam Ravnborg determine their configuration. However, some old PCI motherboards 2732e279b6c1SSam Ravnborg have BIOS bugs and may crash if this is done. Also, some embedded 2733e279b6c1SSam Ravnborg PCI-based systems don't have any BIOS at all. Linux can also try to 2734e279b6c1SSam Ravnborg detect the PCI hardware directly without using the BIOS. 2735e279b6c1SSam Ravnborg 2736e279b6c1SSam Ravnborg With this option, you can specify how Linux should detect the 2737e279b6c1SSam Ravnborg PCI devices. If you choose "BIOS", the BIOS will be used, 2738e279b6c1SSam Ravnborg if you choose "Direct", the BIOS won't be used, and if you 2739e279b6c1SSam Ravnborg choose "MMConfig", then PCI Express MMCONFIG will be used. 2740e279b6c1SSam Ravnborg If you choose "Any", the kernel will try MMCONFIG, then the 2741e279b6c1SSam Ravnborg direct access method and falls back to the BIOS if that doesn't 2742e279b6c1SSam Ravnborg work. If unsure, go with the default, which is "Any". 2743e279b6c1SSam Ravnborg 2744e279b6c1SSam Ravnborgconfig PCI_GOBIOS 2745e279b6c1SSam Ravnborg bool "BIOS" 2746e279b6c1SSam Ravnborg 2747e279b6c1SSam Ravnborgconfig PCI_GOMMCONFIG 2748e279b6c1SSam Ravnborg bool "MMConfig" 2749e279b6c1SSam Ravnborg 2750e279b6c1SSam Ravnborgconfig PCI_GODIRECT 2751e279b6c1SSam Ravnborg bool "Direct" 2752e279b6c1SSam Ravnborg 27533ef0e1f8SAndres Salomonconfig PCI_GOOLPC 275476fb6570SDaniel Drake bool "OLPC XO-1" 27553ef0e1f8SAndres Salomon depends on OLPC 27563ef0e1f8SAndres Salomon 27572bdd1b03SAndres Salomonconfig PCI_GOANY 27582bdd1b03SAndres Salomon bool "Any" 27592bdd1b03SAndres Salomon 2760e279b6c1SSam Ravnborgendchoice 2761e279b6c1SSam Ravnborg 2762e279b6c1SSam Ravnborgconfig PCI_BIOS 27633c2362e6SHarvey Harrison def_bool y 2764efefa6f6SIngo Molnar depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2765e279b6c1SSam Ravnborg 2766e279b6c1SSam Ravnborg# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2767e279b6c1SSam Ravnborgconfig PCI_DIRECT 27683c2362e6SHarvey Harrison def_bool y 27690aba496fSShaohua Li depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2770e279b6c1SSam Ravnborg 2771e279b6c1SSam Ravnborgconfig PCI_MMCONFIG 2772b45c9f36SJan Kiszka bool "Support mmconfig PCI config space access" if X86_64 2773b45c9f36SJan Kiszka default y 27744590d98fSAndy Shevchenko depends on PCI && (ACPI || JAILHOUSE_GUEST) 2775b45c9f36SJan Kiszka depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2776e279b6c1SSam Ravnborg 27773ef0e1f8SAndres Salomonconfig PCI_OLPC 27782bdd1b03SAndres Salomon def_bool y 27792bdd1b03SAndres Salomon depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 27803ef0e1f8SAndres Salomon 2781b5401a96SAlex Nixonconfig PCI_XEN 2782b5401a96SAlex Nixon def_bool y 2783b5401a96SAlex Nixon depends on PCI && XEN 2784b5401a96SAlex Nixon 27858364e1f8SJan Kiszkaconfig MMCONF_FAM10H 27868364e1f8SJan Kiszka def_bool y 27878364e1f8SJan Kiszka depends on X86_64 && PCI_MMCONFIG && ACPI 2788e279b6c1SSam Ravnborg 27893f6ea84aSIra W. Snyderconfig PCI_CNB20LE_QUIRK 27906a108a14SDavid Rientjes bool "Read CNB20LE Host Bridge Windows" if EXPERT 27916ea30386SKees Cook depends on PCI 27923f6ea84aSIra W. Snyder help 27933f6ea84aSIra W. Snyder Read the PCI windows out of the CNB20LE host bridge. This allows 27943f6ea84aSIra W. Snyder PCI hotplug to work on systems with the CNB20LE chipset which do 27953f6ea84aSIra W. Snyder not have ACPI. 27963f6ea84aSIra W. Snyder 279764a5fed6SBjorn Helgaas There's no public spec for this chipset, and this functionality 279864a5fed6SBjorn Helgaas is known to be incomplete. 279964a5fed6SBjorn Helgaas 280064a5fed6SBjorn Helgaas You should say N unless you know you need this. 280164a5fed6SBjorn Helgaas 28023a495511SWilliam Breathitt Grayconfig ISA_BUS 280317a2a129SWilliam Breathitt Gray bool "ISA bus support on modern systems" if EXPERT 28043a495511SWilliam Breathitt Gray help 280517a2a129SWilliam Breathitt Gray Expose ISA bus device drivers and options available for selection and 280617a2a129SWilliam Breathitt Gray configuration. Enable this option if your target machine has an ISA 280717a2a129SWilliam Breathitt Gray bus. ISA is an older system, displaced by PCI and newer bus 280817a2a129SWilliam Breathitt Gray architectures -- if your target machine is modern, it probably does 280917a2a129SWilliam Breathitt Gray not have an ISA bus. 28103a495511SWilliam Breathitt Gray 28113a495511SWilliam Breathitt Gray If unsure, say N. 28123a495511SWilliam Breathitt Gray 28131c00f016SDavid Rientjes# x86_64 have no ISA slots, but can have ISA-style DMA. 2814e279b6c1SSam Ravnborgconfig ISA_DMA_API 28151c00f016SDavid Rientjes bool "ISA-style DMA support" if (X86_64 && EXPERT) 28161c00f016SDavid Rientjes default y 28171c00f016SDavid Rientjes help 28181c00f016SDavid Rientjes Enables ISA-style DMA support for devices requiring such controllers. 28191c00f016SDavid Rientjes If unsure, say Y. 2820e279b6c1SSam Ravnborg 282151e68d05SLinus Torvaldsif X86_32 282251e68d05SLinus Torvalds 2823e279b6c1SSam Ravnborgconfig ISA 2824e279b6c1SSam Ravnborg bool "ISA support" 2825a7f7f624SMasahiro Yamada help 2826e279b6c1SSam Ravnborg Find out whether you have ISA slots on your motherboard. ISA is the 2827e279b6c1SSam Ravnborg name of a bus system, i.e. the way the CPU talks to the other stuff 2828e279b6c1SSam Ravnborg inside your box. Other bus systems are PCI, EISA, MicroChannel 2829e279b6c1SSam Ravnborg (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2830e279b6c1SSam Ravnborg newer boards don't support it. If you have ISA, say Y, otherwise N. 2831e279b6c1SSam Ravnborg 2832e279b6c1SSam Ravnborgconfig SCx200 2833e279b6c1SSam Ravnborg tristate "NatSemi SCx200 support" 2834a7f7f624SMasahiro Yamada help 2835e279b6c1SSam Ravnborg This provides basic support for National Semiconductor's 2836e279b6c1SSam Ravnborg (now AMD's) Geode processors. The driver probes for the 2837e279b6c1SSam Ravnborg PCI-IDs of several on-chip devices, so its a good dependency 2838e279b6c1SSam Ravnborg for other scx200_* drivers. 2839e279b6c1SSam Ravnborg 2840e279b6c1SSam Ravnborg If compiled as a module, the driver is named scx200. 2841e279b6c1SSam Ravnborg 2842e279b6c1SSam Ravnborgconfig SCx200HR_TIMER 2843e279b6c1SSam Ravnborg tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2844592913ecSJohn Stultz depends on SCx200 2845e279b6c1SSam Ravnborg default y 2846a7f7f624SMasahiro Yamada help 2847e279b6c1SSam Ravnborg This driver provides a clocksource built upon the on-chip 2848e279b6c1SSam Ravnborg 27MHz high-resolution timer. Its also a workaround for 2849e279b6c1SSam Ravnborg NSC Geode SC-1100's buggy TSC, which loses time when the 2850e279b6c1SSam Ravnborg processor goes idle (as is done by the scheduler). The 2851e279b6c1SSam Ravnborg other workaround is idle=poll boot option. 2852e279b6c1SSam Ravnborg 28533ef0e1f8SAndres Salomonconfig OLPC 28543ef0e1f8SAndres Salomon bool "One Laptop Per Child support" 285554008979SThomas Gleixner depends on !X86_PAE 28563c554946SAndres Salomon select GPIOLIB 2857dc3119e7SThomas Gleixner select OF 285845bb1674SDaniel Drake select OF_PROMTREE 2859b4e51854SGrant Likely select IRQ_DOMAIN 28600c3d931bSLubomir Rintel select OLPC_EC 2861a7f7f624SMasahiro Yamada help 28623ef0e1f8SAndres Salomon Add support for detecting the unique features of the OLPC 28633ef0e1f8SAndres Salomon XO hardware. 28643ef0e1f8SAndres Salomon 2865a3128588SDaniel Drakeconfig OLPC_XO1_PM 2866a3128588SDaniel Drake bool "OLPC XO-1 Power Management" 2867fa112cf1SBorislav Petkov depends on OLPC && MFD_CS5535=y && PM_SLEEP 2868a7f7f624SMasahiro Yamada help 286997c4cb71SDaniel Drake Add support for poweroff and suspend of the OLPC XO-1 laptop. 2870bf1ebf00SDaniel Drake 2871cfee9597SDaniel Drakeconfig OLPC_XO1_RTC 2872cfee9597SDaniel Drake bool "OLPC XO-1 Real Time Clock" 2873cfee9597SDaniel Drake depends on OLPC_XO1_PM && RTC_DRV_CMOS 2874a7f7f624SMasahiro Yamada help 2875cfee9597SDaniel Drake Add support for the XO-1 real time clock, which can be used as a 2876cfee9597SDaniel Drake programmable wakeup source. 2877cfee9597SDaniel Drake 28787feda8e9SDaniel Drakeconfig OLPC_XO1_SCI 28797feda8e9SDaniel Drake bool "OLPC XO-1 SCI extras" 288092e830f2SArnd Bergmann depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2881ed8e47feSRandy Dunlap depends on INPUT=y 2882d8d01a63SDaniel Drake select POWER_SUPPLY 2883a7f7f624SMasahiro Yamada help 28847feda8e9SDaniel Drake Add support for SCI-based features of the OLPC XO-1 laptop: 28857bc74b3dSDaniel Drake - EC-driven system wakeups 28867feda8e9SDaniel Drake - Power button 28877bc74b3dSDaniel Drake - Ebook switch 28882cf2baeaSDaniel Drake - Lid switch 2889e1040ac6SDaniel Drake - AC adapter status updates 2890e1040ac6SDaniel Drake - Battery status updates 28917feda8e9SDaniel Drake 2892a0f30f59SDaniel Drakeconfig OLPC_XO15_SCI 2893a0f30f59SDaniel Drake bool "OLPC XO-1.5 SCI extras" 2894d8d01a63SDaniel Drake depends on OLPC && ACPI 2895d8d01a63SDaniel Drake select POWER_SUPPLY 2896a7f7f624SMasahiro Yamada help 2897a0f30f59SDaniel Drake Add support for SCI-based features of the OLPC XO-1.5 laptop: 2898a0f30f59SDaniel Drake - EC-driven system wakeups 2899a0f30f59SDaniel Drake - AC adapter status updates 2900a0f30f59SDaniel Drake - Battery status updates 2901e279b6c1SSam Ravnborg 2902d4f3e350SEd Wildgooseconfig ALIX 2903d4f3e350SEd Wildgoose bool "PCEngines ALIX System Support (LED setup)" 2904d4f3e350SEd Wildgoose select GPIOLIB 2905a7f7f624SMasahiro Yamada help 2906d4f3e350SEd Wildgoose This option enables system support for the PCEngines ALIX. 2907d4f3e350SEd Wildgoose At present this just sets up LEDs for GPIO control on 2908d4f3e350SEd Wildgoose ALIX2/3/6 boards. However, other system specific setup should 2909d4f3e350SEd Wildgoose get added here. 2910d4f3e350SEd Wildgoose 2911d4f3e350SEd Wildgoose Note: You must still enable the drivers for GPIO and LED support 2912d4f3e350SEd Wildgoose (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2913d4f3e350SEd Wildgoose 2914d4f3e350SEd Wildgoose Note: You have to set alix.force=1 for boards with Award BIOS. 2915d4f3e350SEd Wildgoose 2916da4e3302SPhilip Prindevilleconfig NET5501 2917da4e3302SPhilip Prindeville bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2918da4e3302SPhilip Prindeville select GPIOLIB 2919a7f7f624SMasahiro Yamada help 2920da4e3302SPhilip Prindeville This option enables system support for the Soekris Engineering net5501. 2921da4e3302SPhilip Prindeville 29223197059aSPhilip A. Prindevilleconfig GEOS 29233197059aSPhilip A. Prindeville bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 29243197059aSPhilip A. Prindeville select GPIOLIB 29253197059aSPhilip A. Prindeville depends on DMI 2926a7f7f624SMasahiro Yamada help 29273197059aSPhilip A. Prindeville This option enables system support for the Traverse Technologies GEOS. 29283197059aSPhilip A. Prindeville 29297d029125SVivien Didelotconfig TS5500 29307d029125SVivien Didelot bool "Technologic Systems TS-5500 platform support" 29317d029125SVivien Didelot depends on MELAN 29327d029125SVivien Didelot select CHECK_SIGNATURE 29337d029125SVivien Didelot select NEW_LEDS 29347d029125SVivien Didelot select LEDS_CLASS 2935a7f7f624SMasahiro Yamada help 29367d029125SVivien Didelot This option enables system support for the Technologic Systems TS-5500. 29377d029125SVivien Didelot 2938e279b6c1SSam Ravnborgendif # X86_32 2939e279b6c1SSam Ravnborg 294023ac4ae8SAndreas Herrmannconfig AMD_NB 2941e279b6c1SSam Ravnborg def_bool y 29420e152cd7SBorislav Petkov depends on CPU_SUP_AMD && PCI 2943e279b6c1SSam Ravnborg 2944e279b6c1SSam Ravnborgendmenu 2945e279b6c1SSam Ravnborg 29461572497cSChristoph Hellwigmenu "Binary Emulations" 2947e279b6c1SSam Ravnborg 2948e279b6c1SSam Ravnborgconfig IA32_EMULATION 2949e279b6c1SSam Ravnborg bool "IA32 Emulation" 2950e279b6c1SSam Ravnborg depends on X86_64 295139f88911SIngo Molnar select ARCH_WANT_OLD_COMPAT_IPC 2952d1603990SRandy Dunlap select BINFMT_ELF 295339f88911SIngo Molnar select COMPAT_OLD_SIGACTION 2954a7f7f624SMasahiro Yamada help 29555fd92e65SH. J. Lu Include code to run legacy 32-bit programs under a 29565fd92e65SH. J. Lu 64-bit kernel. You should likely turn this on, unless you're 29575fd92e65SH. J. Lu 100% sure that you don't have any 32-bit programs left. 2958e279b6c1SSam Ravnborg 295983a44a4fSMasahiro Yamadaconfig X86_X32_ABI 29606ea30386SKees Cook bool "x32 ABI for 64-bit mode" 29619b54050bSBrian Gerst depends on X86_64 2962aaeed6ecSNathan Chancellor # llvm-objcopy does not convert x86_64 .note.gnu.property or 2963aaeed6ecSNathan Chancellor # compressed debug sections to x86_x32 properly: 2964aaeed6ecSNathan Chancellor # https://github.com/ClangBuiltLinux/linux/issues/514 2965aaeed6ecSNathan Chancellor # https://github.com/ClangBuiltLinux/linux/issues/1141 2966aaeed6ecSNathan Chancellor depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm) 2967a7f7f624SMasahiro Yamada help 29685fd92e65SH. J. Lu Include code to run binaries for the x32 native 32-bit ABI 29695fd92e65SH. J. Lu for 64-bit processors. An x32 process gets access to the 29705fd92e65SH. J. Lu full 64-bit register file and wide data path while leaving 29715fd92e65SH. J. Lu pointers at 32 bits for smaller memory footprint. 29725fd92e65SH. J. Lu 2973953fee1dSIngo Molnarconfig COMPAT_32 2974953fee1dSIngo Molnar def_bool y 2975953fee1dSIngo Molnar depends on IA32_EMULATION || X86_32 2976953fee1dSIngo Molnar select HAVE_UID16 2977953fee1dSIngo Molnar select OLD_SIGSUSPEND3 2978953fee1dSIngo Molnar 2979e279b6c1SSam Ravnborgconfig COMPAT 29803c2362e6SHarvey Harrison def_bool y 298183a44a4fSMasahiro Yamada depends on IA32_EMULATION || X86_X32_ABI 2982e279b6c1SSam Ravnborg 2983e279b6c1SSam Ravnborgconfig COMPAT_FOR_U64_ALIGNMENT 29843120e25eSJan Beulich def_bool y 2985a9251280SLinus Torvalds depends on COMPAT 2986ee009e4aSDavid Howells 2987e279b6c1SSam Ravnborgendmenu 2988e279b6c1SSam Ravnborg 2989e5beae16SKeith Packardconfig HAVE_ATOMIC_IOMAP 2990e5beae16SKeith Packard def_bool y 2991e5beae16SKeith Packard depends on X86_32 2992e5beae16SKeith Packard 2993edf88417SAvi Kivitysource "arch/x86/kvm/Kconfig" 29945e8ebd84SJason A. Donenfeld 29955e8ebd84SJason A. Donenfeldsource "arch/x86/Kconfig.assembler" 2996