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 HAVE_ARCH_SOFT_DIRTY 32d94e0685SIngo Molnar select MODULES_USE_ELF_RELA 33f616ab59SChristoph Hellwig select NEED_DMA_MAP_STATE 3409230cbcSChristoph Hellwig select SWIOTLB 357facdc42SAl Viro select ARCH_HAS_ELFCORE_COMPAT 3663703f37SKefeng Wang select ZONE_DMA32 371032c0baSSam Ravnborg 38518049d9SSteven Rostedt (VMware)config FORCE_DYNAMIC_FTRACE 39518049d9SSteven Rostedt (VMware) def_bool y 40518049d9SSteven Rostedt (VMware) depends on X86_32 41518049d9SSteven Rostedt (VMware) depends on FUNCTION_TRACER 42518049d9SSteven Rostedt (VMware) select DYNAMIC_FTRACE 43518049d9SSteven Rostedt (VMware) help 44518049d9SSteven Rostedt (VMware) We keep the static function tracing (!DYNAMIC_FTRACE) around 45518049d9SSteven Rostedt (VMware) in order to test the non static function tracing in the 46518049d9SSteven Rostedt (VMware) generic code, as other architectures still use it. But we 47518049d9SSteven Rostedt (VMware) only need to keep it around for x86_64. No need to keep it 48518049d9SSteven Rostedt (VMware) for x86_32. For x86_32, force DYNAMIC_FTRACE. 49d94e0685SIngo Molnar# 50d94e0685SIngo Molnar# Arch settings 51d94e0685SIngo Molnar# 52d94e0685SIngo Molnar# ( Note that options that are marked 'if X86_64' could in principle be 53d94e0685SIngo Molnar# ported to 32-bit as well. ) 54d94e0685SIngo Molnar# 558d5fffb9SSam Ravnborgconfig X86 563c2362e6SHarvey Harrison def_bool y 57c763ea26SIngo Molnar # 58c763ea26SIngo Molnar # Note: keep this list sorted alphabetically 59c763ea26SIngo Molnar # 606471b825SIngo Molnar select ACPI_LEGACY_TABLES_LOOKUP if ACPI 616e0a0ea1SGraeme Gregory select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 62a02f66bbSJames Morse select ACPI_HOTPLUG_CPU if ACPI_PROCESSOR && HOTPLUG_CPU 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 758f23f5dbSJason Gunthorpe select ARCH_HAS_CPU_PASID if IOMMU_SVA 762792d84eSKees Cook select ARCH_HAS_CURRENT_STACK_POINTER 77fa5b6ec9SLaura Abbott select ARCH_HAS_DEBUG_VIRTUAL 78399145f9SAnshuman Khandual select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 7921266be9SDan Williams select ARCH_HAS_DEVMEM_IS_ALLOWED 80b1a57bbfSDouglas Anderson select ARCH_HAS_EARLY_DEBUG if KGDB 816471b825SIngo Molnar select ARCH_HAS_ELF_RANDOMIZE 8272d93104SLinus Torvalds select ARCH_HAS_FAST_MULTIPLIER 836974f0c4SDaniel Micay select ARCH_HAS_FORTIFY_SOURCE 84957e3facSRiku Voipio select ARCH_HAS_GCOV_PROFILE_ALL 85bece04b5SMarco Elver select ARCH_HAS_KCOV if X86_64 860c9c1d56SThiago Jung Bauermann select ARCH_HAS_MEM_ENCRYPT 8710bcc80eSMathieu Desnoyers select ARCH_HAS_MEMBARRIER_SYNC_CORE 8849f88c70SPaul E. McKenney select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS 890ebeea8cSDaniel Borkmann select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 90c763ea26SIngo Molnar select ARCH_HAS_PMEM_API if X86_64 9117596731SRobin Murphy select ARCH_HAS_PTE_DEVMAP if X86_64 923010a5eaSLaurent Dufour select ARCH_HAS_PTE_SPECIAL 9371ce1ab5SKinsey Ho select ARCH_HAS_HW_PTE_YOUNG 94eed9a328SYu Zhao select ARCH_HAS_NONLEAF_PMD_YOUNG if PGTABLE_LEVELS > 2 950aed55afSDan Williams select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 96ec6347bbSDan Williams select ARCH_HAS_COPY_MC if X86_64 97d2852a22SDaniel Borkmann select ARCH_HAS_SET_MEMORY 98d253ca0cSRick Edgecombe select ARCH_HAS_SET_DIRECT_MAP 99ad21fc4fSLaura Abbott select ARCH_HAS_STRICT_KERNEL_RWX 100ad21fc4fSLaura Abbott select ARCH_HAS_STRICT_MODULE_RWX 101ac1ab12aSMathieu Desnoyers select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 10225c619e5SBrian Gerst select ARCH_HAS_SYSCALL_WRAPPER 103c6d30853SAndrey Ryabinin select ARCH_HAS_UBSAN_SANITIZE_ALL 1047e01ccb4SZong Li select ARCH_HAS_DEBUG_WX 10563703f37SKefeng Wang select ARCH_HAS_ZONE_DMA_SET if EXPERT 1066471b825SIngo Molnar select ARCH_HAVE_NMI_SAFE_CMPXCHG 10704d5ea46SAneesh Kumar K.V select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 1086471b825SIngo Molnar select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 10977fbbc81SMark Salter select ARCH_MIGHT_HAVE_PC_PARPORT 1105e2c18c0SMark Salter select ARCH_MIGHT_HAVE_PC_SERIO 1113599fe12SThomas Gleixner select ARCH_STACKWALK 1122c870e61SArnd Bergmann select ARCH_SUPPORTS_ACPI 1136471b825SIngo Molnar select ARCH_SUPPORTS_ATOMIC_RMW 1145d6ad668SMike Rapoport select ARCH_SUPPORTS_DEBUG_PAGEALLOC 115d283d422SPasha Tatashin select ARCH_SUPPORTS_PAGE_TABLE_CHECK if X86_64 1166471b825SIngo Molnar select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 11714df3267SThomas Gleixner select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 1183c516f89SSami Tolvanen select ARCH_SUPPORTS_CFI_CLANG if X86_64 1193c516f89SSami Tolvanen select ARCH_USES_CFI_TRAPS if X86_64 && CFI_CLANG 120583bfd48SNathan Chancellor select ARCH_SUPPORTS_LTO_CLANG 121583bfd48SNathan Chancellor select ARCH_SUPPORTS_LTO_CLANG_THIN 1226471b825SIngo Molnar select ARCH_USE_BUILTIN_BSWAP 123a432b7c0SUros Bizjak select ARCH_USE_CMPXCHG_LOCKREF if X86_CMPXCHG64 124dce44566SAnshuman Khandual select ARCH_USE_MEMTEST 1256471b825SIngo Molnar select ARCH_USE_QUEUED_RWLOCKS 1266471b825SIngo Molnar select ARCH_USE_QUEUED_SPINLOCKS 1272ce0d7f9SMark Brown select ARCH_USE_SYM_ANNOTATIONS 128ce4a4e56SAndy Lutomirski select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 12981c22041SDaniel Borkmann select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 130c763ea26SIngo Molnar select ARCH_WANTS_DYNAMIC_TASK_STRUCT 13151c2ee6dSNick Desaulniers select ARCH_WANTS_NO_INSTR 13207431506SAnshuman Khandual select ARCH_WANT_GENERAL_HUGETLB 1333876d4a3SAlexandre Ghiti select ARCH_WANT_HUGE_PMD_SHARE 13459612b24SNathan Chancellor select ARCH_WANT_LD_ORPHAN_WARN 1350b6f1582SAneesh Kumar K.V select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP if X86_64 1360b6f1582SAneesh Kumar K.V select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP if X86_64 13738d8b4e6SHuang Ying select ARCH_WANTS_THP_SWAP if X86_64 138b5f06f64SBalbir Singh select ARCH_HAS_PARANOID_L1D_FLUSH 13910916706SShile Zhang select BUILDTIME_TABLE_SORT 1406471b825SIngo Molnar select CLKEVT_I8253 1416471b825SIngo Molnar select CLOCKSOURCE_VALIDATE_LAST_CYCLE 1426471b825SIngo Molnar select CLOCKSOURCE_WATCHDOG 1437cf8f44aSAlexander Potapenko # Word-size accesses may read uninitialized data past the trailing \0 1447cf8f44aSAlexander Potapenko # in strings and cause false KMSAN reports. 1457cf8f44aSAlexander Potapenko select DCACHE_WORD_ACCESS if !KMSAN 1463aac3ebeSThomas Gleixner select DYNAMIC_SIGFRAME 14745471cd9SLinus Torvalds select EDAC_ATOMIC_SCRUB 14845471cd9SLinus Torvalds select EDAC_SUPPORT 1496471b825SIngo Molnar select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 150*cb81deefSThomas Gleixner select GENERIC_CLOCKEVENTS_BROADCAST_IDLE if GENERIC_CLOCKEVENTS_BROADCAST 1516471b825SIngo Molnar select GENERIC_CLOCKEVENTS_MIN_ADJUST 1526471b825SIngo Molnar select GENERIC_CMOS_UPDATE 1536471b825SIngo Molnar select GENERIC_CPU_AUTOPROBE 1545b95f94cSJames Morse select GENERIC_CPU_DEVICES 15561dc0f55SThomas Gleixner select GENERIC_CPU_VULNERABILITIES 1566471b825SIngo Molnar select GENERIC_EARLY_IOREMAP 15727d6b4d1SThomas Gleixner select GENERIC_ENTRY 1586471b825SIngo Molnar select GENERIC_IOMAP 159c7d6c9ddSThomas Gleixner select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 1600fa115daSThomas Gleixner select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 161ad7a929fSThomas Gleixner select GENERIC_IRQ_MIGRATION if SMP 1626471b825SIngo Molnar select GENERIC_IRQ_PROBE 163c201c917SThomas Gleixner select GENERIC_IRQ_RESERVATION_MODE 1646471b825SIngo Molnar select GENERIC_IRQ_SHOW 1656471b825SIngo Molnar select GENERIC_PENDING_IRQ if SMP 1662ae27137SSteven Price select GENERIC_PTDUMP 1676471b825SIngo Molnar select GENERIC_SMP_IDLE_THREAD 1686471b825SIngo Molnar select GENERIC_TIME_VSYSCALL 1697ac87074SVincenzo Frascino select GENERIC_GETTIMEOFDAY 170550a77a7SDmitry Safonov select GENERIC_VDSO_TIME_NS 1716ca297d4SPeter Zijlstra select GUP_GET_PXX_LOW_HIGH if X86_PAE 17217e5888eSHans de Goede select HARDIRQS_SW_RESEND 1737edaeb68SThomas Gleixner select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 174fcbfe812SNiklas Schnelle select HAS_IOPORT 1756471b825SIngo Molnar select HAVE_ACPI_APEI if ACPI 1766471b825SIngo Molnar select HAVE_ACPI_APEI_NMI if ACPI 1772a19be61SVlastimil Babka select HAVE_ALIGNED_STRUCT_PAGE 1786471b825SIngo Molnar select HAVE_ARCH_AUDITSYSCALL 1796471b825SIngo Molnar select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 180eed1fceeSSong Liu select HAVE_ARCH_HUGE_VMALLOC if X86_64 1816471b825SIngo Molnar select HAVE_ARCH_JUMP_LABEL 182b34006c4SArd Biesheuvel select HAVE_ARCH_JUMP_LABEL_RELATIVE 183d17a1d97SAndrey Ryabinin select HAVE_ARCH_KASAN if X86_64 1840609ae01SDaniel Axtens select HAVE_ARCH_KASAN_VMALLOC if X86_64 1851dc0da6eSAlexander Potapenko select HAVE_ARCH_KFENCE 1864ca8cc8dSAlexander Potapenko select HAVE_ARCH_KMSAN if X86_64 1876471b825SIngo Molnar select HAVE_ARCH_KGDB 1889e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_BITS if MMU 1899e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 1901b028f78SDmitry Safonov select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 191271ca788SArd Biesheuvel select HAVE_ARCH_PREL32_RELOCATIONS 1926471b825SIngo Molnar select HAVE_ARCH_SECCOMP_FILTER 193f7d83c1cSKees Cook select HAVE_ARCH_THREAD_STRUCT_WHITELIST 194afaef01cSAlexander Popov select HAVE_ARCH_STACKLEAK 1956471b825SIngo Molnar select HAVE_ARCH_TRACEHOOK 1966471b825SIngo Molnar select HAVE_ARCH_TRANSPARENT_HUGEPAGE 197a00cc7d9SMatthew Wilcox select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 198b64d8d1eSPeter Xu select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 1997677f7fdSAxel Rasmussen select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 200e37e43a4SAndy Lutomirski select HAVE_ARCH_VMAP_STACK if X86_64 201fe950f60SKees Cook select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 202c763ea26SIngo Molnar select HAVE_ARCH_WITHIN_STACK_FRAMES 2032ff2b7ecSMasahiro Yamada select HAVE_ASM_MODVERSIONS 2046471b825SIngo Molnar select HAVE_CMPXCHG_DOUBLE 2056471b825SIngo Molnar select HAVE_CMPXCHG_LOCAL 20624a9c541SFrederic Weisbecker select HAVE_CONTEXT_TRACKING_USER if X86_64 20724a9c541SFrederic Weisbecker select HAVE_CONTEXT_TRACKING_USER_OFFSTACK if HAVE_CONTEXT_TRACKING_USER 2086471b825SIngo Molnar select HAVE_C_RECORDMCOUNT 20903f16cd0SJosh Poimboeuf select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL 210280981d6SSathvika Vasireddy select HAVE_OBJTOOL_NOP_MCOUNT if HAVE_OBJTOOL_MCOUNT 2114ed308c4SSteven Rostedt (Google) select HAVE_BUILDTIME_MCOUNT_SORT 2126471b825SIngo Molnar select HAVE_DEBUG_KMEMLEAK 2139c5a3621SAkinobu Mita select HAVE_DMA_CONTIGUOUS 214677aa9f7SSteven Rostedt select HAVE_DYNAMIC_FTRACE 21506aeaaeaSMasami Hiramatsu select HAVE_DYNAMIC_FTRACE_WITH_REGS 21602a474caSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 217562955feSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 218c316eb44SHeiko Carstens select HAVE_SAMPLE_FTRACE_DIRECT if X86_64 219503e4510SHeiko Carstens select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64 22003f5781bSWang YanQing select HAVE_EBPF_JIT 22158340a07SJohannes Berg select HAVE_EFFICIENT_UNALIGNED_ACCESS 2226630a8e5SChristoph Hellwig select HAVE_EISA 2235f56a5dfSJiri Slaby select HAVE_EXIT_THREAD 22467a929e0SChristoph Hellwig select HAVE_FAST_GUP 225644e0e8dSSteven Rostedt (VMware) select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 2266471b825SIngo Molnar select HAVE_FTRACE_MCOUNT_RECORD 227d938ba17SDonglin Peng select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER 2284a30e4c9SSteven Rostedt (VMware) select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) 2296471b825SIngo Molnar select HAVE_FUNCTION_TRACER 2306b90bd4bSEmese Revfy select HAVE_GCC_PLUGINS 2310067f129SK.Prasad select HAVE_HW_BREAKPOINT 2326471b825SIngo Molnar select HAVE_IOREMAP_PROT 233624db9eaSThomas Gleixner select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 2346471b825SIngo Molnar select HAVE_IRQ_TIME_ACCOUNTING 2354ab7674fSJosh Poimboeuf select HAVE_JUMP_LABEL_HACK if HAVE_OBJTOOL 2366471b825SIngo Molnar select HAVE_KERNEL_BZIP2 2376471b825SIngo Molnar select HAVE_KERNEL_GZIP 2386471b825SIngo Molnar select HAVE_KERNEL_LZ4 2396471b825SIngo Molnar select HAVE_KERNEL_LZMA 2406471b825SIngo Molnar select HAVE_KERNEL_LZO 2416471b825SIngo Molnar select HAVE_KERNEL_XZ 242fb46d057SNick Terrell select HAVE_KERNEL_ZSTD 2436471b825SIngo Molnar select HAVE_KPROBES 2446471b825SIngo Molnar select HAVE_KPROBES_ON_FTRACE 245540adea3SMasami Hiramatsu select HAVE_FUNCTION_ERROR_INJECTION 2466471b825SIngo Molnar select HAVE_KRETPROBES 247f3a112c0SMasami Hiramatsu select HAVE_RETHOOK 2486471b825SIngo Molnar select HAVE_KVM 2496471b825SIngo Molnar select HAVE_LIVEPATCH if X86_64 2500102752eSFrederic Weisbecker select HAVE_MIXED_BREAKPOINTS_REGS 251ee9f8fceSJosh Poimboeuf select HAVE_MOD_ARCH_SPECIFIC 2529f132f7eSJoel Fernandes (Google) select HAVE_MOVE_PMD 253be37c98dSKalesh Singh select HAVE_MOVE_PUD 25422102f45SJosh Poimboeuf select HAVE_NOINSTR_HACK if HAVE_OBJTOOL 25542a0bb3fSPetr Mladek select HAVE_NMI 256489e355bSJosh Poimboeuf select HAVE_NOINSTR_VALIDATION if HAVE_OBJTOOL 25703f16cd0SJosh Poimboeuf select HAVE_OBJTOOL if X86_64 2586471b825SIngo Molnar select HAVE_OPTPROBES 2596471b825SIngo Molnar select HAVE_PCSPKR_PLATFORM 2606471b825SIngo Molnar select HAVE_PERF_EVENTS 261c01d4323SFrederic Weisbecker select HAVE_PERF_EVENTS_NMI 26292e5aae4SNicholas Piggin select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 263eb01d42aSChristoph Hellwig select HAVE_PCI 264c5e63197SJiri Olsa select HAVE_PERF_REGS 265c5ebcedbSJiri Olsa select HAVE_PERF_USER_STACK_DUMP 266ff2e6d72SPeter Zijlstra select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 2671e9fdf21SPeter Zijlstra select MMU_GATHER_MERGE_VMAS 26800998085SThomas Gleixner select HAVE_POSIX_CPU_TIMERS_TASK_WORK 2696471b825SIngo Molnar select HAVE_REGS_AND_STACK_ACCESS_API 27003f16cd0SJosh Poimboeuf select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC || STACK_VALIDATION 2713c88ee19SMasami Hiramatsu select HAVE_FUNCTION_ARG_ACCESS_API 2727ecd19cfSKefeng Wang select HAVE_SETUP_PER_CPU_AREA 273cd1a41ceSThomas Gleixner select HAVE_SOFTIRQ_ON_OWN_STACK 274d148eac0SMasahiro Yamada select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 27503f16cd0SJosh Poimboeuf select HAVE_STACK_VALIDATION if HAVE_OBJTOOL 276e6d6c071SJosh Poimboeuf select HAVE_STATIC_CALL 27703f16cd0SJosh Poimboeuf select HAVE_STATIC_CALL_INLINE if HAVE_OBJTOOL 27899cf983cSMark Rutland select HAVE_PREEMPT_DYNAMIC_CALL 279d6761b8fSMathieu Desnoyers select HAVE_RSEQ 28009498135SMiguel Ojeda select HAVE_RUST if X86_64 2816471b825SIngo Molnar select HAVE_SYSCALL_TRACEPOINTS 2825f3da8c0SJosh Poimboeuf select HAVE_UACCESS_VALIDATION if HAVE_OBJTOOL 2836471b825SIngo Molnar select HAVE_UNSTABLE_SCHED_CLOCK 2847c68af6eSAvi Kivity select HAVE_USER_RETURN_NOTIFIER 2857ac87074SVincenzo Frascino select HAVE_GENERIC_VDSO 2860c7ffa32SThomas Gleixner select HOTPLUG_PARALLEL if SMP && X86_64 28705736e4aSThomas Gleixner select HOTPLUG_SMT if SMP 2880c7ffa32SThomas Gleixner select HOTPLUG_SPLIT_STARTUP if SMP && X86_32 289c0185808SThomas Gleixner select IRQ_FORCED_THREADING 290c2508ec5SLinus Torvalds select LOCK_MM_AND_FIND_VMA 2917ecd19cfSKefeng Wang select NEED_PER_CPU_EMBED_FIRST_CHUNK 2927ecd19cfSKefeng Wang select NEED_PER_CPU_PAGE_FIRST_CHUNK 29386596f0aSChristoph Hellwig select NEED_SG_DMA_LENGTH 2942eac9c2dSChristoph Hellwig select PCI_DOMAINS if PCI 295625210cfSSinan Kaya select PCI_LOCKLESS_CONFIG if PCI 2966471b825SIngo Molnar select PERF_EVENTS 2973195ef59SPrarit Bhargava select RTC_LIB 298d6faca40SArnd Bergmann select RTC_MC146818_LIB 2996471b825SIngo Molnar select SPARSE_IRQ 3006471b825SIngo Molnar select SYSCTL_EXCEPTION_TRACE 30115f4eae7SAndy Lutomirski select THREAD_INFO_IN_TASK 3024aae683fSMasahiro Yamada select TRACE_IRQFLAGS_SUPPORT 3034510bffbSMark Rutland select TRACE_IRQFLAGS_NMI_SUPPORT 3046471b825SIngo Molnar select USER_STACKTRACE_SUPPORT 3053b02a051SIngo Molnar select HAVE_ARCH_KCSAN if X86_64 3060c608dadSAubrey Li select PROC_PID_ARCH_STATUS if PROC_FS 30750468e43SJarkko Sakkinen select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX 308d49a0626SPeter Zijlstra select FUNCTION_ALIGNMENT_16B if X86_64 || X86_ALIGNMENT_16 309d49a0626SPeter Zijlstra select FUNCTION_ALIGNMENT_4B 3109e2b4be3SNayna Jain imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 311ceea991aSJiri Olsa select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 3127d8330a5SBalbir Singh 313ba7e4d13SIngo Molnarconfig INSTRUCTION_DECODER 3143120e25eSJan Beulich def_bool y 3153120e25eSJan Beulich depends on KPROBES || PERF_EVENTS || UPROBES 316ba7e4d13SIngo Molnar 31751b26adaSLinus Torvaldsconfig OUTPUT_FORMAT 31851b26adaSLinus Torvalds string 31951b26adaSLinus Torvalds default "elf32-i386" if X86_32 32051b26adaSLinus Torvalds default "elf64-x86-64" if X86_64 32151b26adaSLinus Torvalds 3228d5fffb9SSam Ravnborgconfig LOCKDEP_SUPPORT 3233c2362e6SHarvey Harrison def_bool y 3248d5fffb9SSam Ravnborg 3258d5fffb9SSam Ravnborgconfig STACKTRACE_SUPPORT 3263c2362e6SHarvey Harrison def_bool y 3278d5fffb9SSam Ravnborg 3288d5fffb9SSam Ravnborgconfig MMU 3293c2362e6SHarvey Harrison def_bool y 3308d5fffb9SSam Ravnborg 3319e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MIN 3329e08f57dSDaniel Cashman default 28 if 64BIT 3339e08f57dSDaniel Cashman default 8 3349e08f57dSDaniel Cashman 3359e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MAX 3369e08f57dSDaniel Cashman default 32 if 64BIT 3379e08f57dSDaniel Cashman default 16 3389e08f57dSDaniel Cashman 3399e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MIN 3409e08f57dSDaniel Cashman default 8 3419e08f57dSDaniel Cashman 3429e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MAX 3439e08f57dSDaniel Cashman default 16 3449e08f57dSDaniel Cashman 3458d5fffb9SSam Ravnborgconfig SBUS 3468d5fffb9SSam Ravnborg bool 3478d5fffb9SSam Ravnborg 3488d5fffb9SSam Ravnborgconfig GENERIC_ISA_DMA 3493120e25eSJan Beulich def_bool y 3503120e25eSJan Beulich depends on ISA_DMA_API 3518d5fffb9SSam Ravnborg 352d911c67eSAlexander Potapenkoconfig GENERIC_CSUM 353d911c67eSAlexander Potapenko bool 354d911c67eSAlexander Potapenko default y if KMSAN || KASAN 355d911c67eSAlexander Potapenko 3568d5fffb9SSam Ravnborgconfig GENERIC_BUG 3573c2362e6SHarvey Harrison def_bool y 3588d5fffb9SSam Ravnborg depends on BUG 359b93a531eSJan Beulich select GENERIC_BUG_RELATIVE_POINTERS if X86_64 360b93a531eSJan Beulich 361b93a531eSJan Beulichconfig GENERIC_BUG_RELATIVE_POINTERS 362b93a531eSJan Beulich bool 3638d5fffb9SSam Ravnborg 3648d5fffb9SSam Ravnborgconfig ARCH_MAY_HAVE_PC_FDC 3653120e25eSJan Beulich def_bool y 3663120e25eSJan Beulich depends on ISA_DMA_API 3678d5fffb9SSam Ravnborg 3681032c0baSSam Ravnborgconfig GENERIC_CALIBRATE_DELAY 3691032c0baSSam Ravnborg def_bool y 3701032c0baSSam Ravnborg 3719a0b8415Svenkatesh.pallipadi@intel.comconfig ARCH_HAS_CPU_RELAX 3729a0b8415Svenkatesh.pallipadi@intel.com def_bool y 3738d5fffb9SSam Ravnborg 374801e4062SJohannes Bergconfig ARCH_HIBERNATION_POSSIBLE 375801e4062SJohannes Berg def_bool y 376801e4062SJohannes Berg 377f4cb5700SJohannes Bergconfig ARCH_SUSPEND_POSSIBLE 378f4cb5700SJohannes Berg def_bool y 379f4cb5700SJohannes Berg 3808d5fffb9SSam Ravnborgconfig AUDIT_ARCH 381e0fd24a3SJan Beulich def_bool y if X86_64 3828d5fffb9SSam Ravnborg 383d6f2d75aSAndrey Ryabininconfig KASAN_SHADOW_OFFSET 384d6f2d75aSAndrey Ryabinin hex 385d6f2d75aSAndrey Ryabinin depends on KASAN 386d6f2d75aSAndrey Ryabinin default 0xdffffc0000000000 387d6f2d75aSAndrey Ryabinin 38869575d38SShane Wangconfig HAVE_INTEL_TXT 38969575d38SShane Wang def_bool y 3906ea30386SKees Cook depends on INTEL_IOMMU && ACPI 39169575d38SShane Wang 3926b0c3d44SSam Ravnborgconfig X86_64_SMP 3936b0c3d44SSam Ravnborg def_bool y 3946b0c3d44SSam Ravnborg depends on X86_64 && SMP 3956b0c3d44SSam Ravnborg 3962b144498SSrikar Dronamrajuconfig ARCH_SUPPORTS_UPROBES 3972b144498SSrikar Dronamraju def_bool y 3982b144498SSrikar Dronamraju 399d20642f0SRob Herringconfig FIX_EARLYCON_MEM 400d20642f0SRob Herring def_bool y 401d20642f0SRob Herring 40294d49eb3SKirill A. Shutemovconfig DYNAMIC_PHYSICAL_MASK 40394d49eb3SKirill A. Shutemov bool 40494d49eb3SKirill A. Shutemov 40598233368SKirill A. Shutemovconfig PGTABLE_LEVELS 40698233368SKirill A. Shutemov int 40777ef56e4SKirill A. Shutemov default 5 if X86_5LEVEL 40898233368SKirill A. Shutemov default 4 if X86_64 40998233368SKirill A. Shutemov default 3 if X86_PAE 41098233368SKirill A. Shutemov default 2 41198233368SKirill A. Shutemov 4122a61f474SMasahiro Yamadaconfig CC_HAS_SANE_STACKPROTECTOR 4132a61f474SMasahiro Yamada bool 4141b866781SNathan Chancellor default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT 4151b866781SNathan Chancellor default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) 4162a61f474SMasahiro Yamada help 4172a61f474SMasahiro Yamada We have to make sure stack protector is unconditionally disabled if 4183fb0fdb3SAndy Lutomirski the compiler produces broken code or if it does not let us control 4193fb0fdb3SAndy Lutomirski the segment on 32-bit kernels. 4202a61f474SMasahiro Yamada 421506f1d07SSam Ravnborgmenu "Processor type and features" 422506f1d07SSam Ravnborg 423506f1d07SSam Ravnborgconfig SMP 424506f1d07SSam Ravnborg bool "Symmetric multi-processing support" 425a7f7f624SMasahiro Yamada help 426506f1d07SSam Ravnborg This enables support for systems with more than one CPU. If you have 4274a474157SRobert Graffham a system with only one CPU, say N. If you have a system with more 4284a474157SRobert Graffham than one CPU, say Y. 429506f1d07SSam Ravnborg 4304a474157SRobert Graffham If you say N here, the kernel will run on uni- and multiprocessor 431506f1d07SSam Ravnborg machines, but will use only one CPU of a multiprocessor machine. If 432506f1d07SSam Ravnborg you say Y here, the kernel will run on many, but not all, 4334a474157SRobert Graffham uniprocessor machines. On a uniprocessor machine, the kernel 434506f1d07SSam Ravnborg will run faster if you say N here. 435506f1d07SSam Ravnborg 436506f1d07SSam Ravnborg Note that if you say Y here and choose architecture "586" or 437506f1d07SSam Ravnborg "Pentium" under "Processor family", the kernel will not work on 486 438506f1d07SSam Ravnborg architectures. Similarly, multiprocessor kernels for the "PPro" 439506f1d07SSam Ravnborg architecture may not work on all Pentium based boards. 440506f1d07SSam Ravnborg 441506f1d07SSam Ravnborg People using multiprocessor machines who say Y here should also say 442506f1d07SSam Ravnborg Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 443506f1d07SSam Ravnborg Management" code will be disabled if you say Y here. 444506f1d07SSam Ravnborg 445ff61f079SJonathan Corbet See also <file:Documentation/arch/x86/i386/IO-APIC.rst>, 4464f4cfa6cSMauro Carvalho Chehab <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 447506f1d07SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 448506f1d07SSam Ravnborg 449506f1d07SSam Ravnborg If you don't know what to do here, say N. 450506f1d07SSam Ravnborg 45106cd9a7dSYinghai Luconfig X86_X2APIC 45206cd9a7dSYinghai Lu bool "Support x2apic" 45319e3d60dSJan Kiszka depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 454a7f7f624SMasahiro Yamada help 45506cd9a7dSYinghai Lu This enables x2apic support on CPUs that have this feature. 45606cd9a7dSYinghai Lu 45706cd9a7dSYinghai Lu This allows 32-bit apic IDs (so it can support very large systems), 45806cd9a7dSYinghai Lu and accesses the local apic via MSRs not via mmio. 45906cd9a7dSYinghai Lu 460b8d1d163SDaniel Sneddon Some Intel systems circa 2022 and later are locked into x2APIC mode 461b8d1d163SDaniel Sneddon and can not fall back to the legacy APIC modes if SGX or TDX are 462e3998434SMateusz Jończyk enabled in the BIOS. They will boot with very reduced functionality 463e3998434SMateusz Jończyk without enabling this option. 464b8d1d163SDaniel Sneddon 46506cd9a7dSYinghai Lu If you don't know what to do here, say N. 46606cd9a7dSYinghai Lu 4676695c85bSYinghai Luconfig X86_MPPARSE 4684590d98fSAndy Shevchenko bool "Enable MPS table" if ACPI 4697a527688SJan Beulich default y 4705ab74722SIngo Molnar depends on X86_LOCAL_APIC 471a7f7f624SMasahiro Yamada help 4726695c85bSYinghai Lu For old smp systems that do not have proper acpi support. Newer systems 4736695c85bSYinghai Lu (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 4746695c85bSYinghai Lu 475ddd70cf9SJun Nakajimaconfig GOLDFISH 476ddd70cf9SJun Nakajima def_bool y 477ddd70cf9SJun Nakajima depends on X86_GOLDFISH 478ddd70cf9SJun Nakajima 479e6d42931SJohannes Weinerconfig X86_CPU_RESCTRL 480e6d42931SJohannes Weiner bool "x86 CPU resource control support" 4816fe07ce3SBabu Moger depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 48259fe5a77SThomas Gleixner select KERNFS 483e79f15a4SChen Yu select PROC_CPU_RESCTRL if PROC_FS 48478e99b4aSFenghua Yu help 485e6d42931SJohannes Weiner Enable x86 CPU resource control support. 4866fe07ce3SBabu Moger 4876fe07ce3SBabu Moger Provide support for the allocation and monitoring of system resources 4886fe07ce3SBabu Moger usage by the CPU. 4896fe07ce3SBabu Moger 4906fe07ce3SBabu Moger Intel calls this Intel Resource Director Technology 4916fe07ce3SBabu Moger (Intel(R) RDT). More information about RDT can be found in the 4926fe07ce3SBabu Moger Intel x86 Architecture Software Developer Manual. 4936fe07ce3SBabu Moger 4946fe07ce3SBabu Moger AMD calls this AMD Platform Quality of Service (AMD QoS). 4956fe07ce3SBabu Moger More information about AMD QoS can be found in the AMD64 Technology 4966fe07ce3SBabu Moger Platform Quality of Service Extensions manual. 49778e99b4aSFenghua Yu 49878e99b4aSFenghua Yu Say N if unsure. 49978e99b4aSFenghua Yu 5008425091fSRavikiran G Thirumalaiif X86_32 501a0d0bb4dSRandy Dunlapconfig X86_BIGSMP 502a0d0bb4dSRandy Dunlap bool "Support for big SMP systems with more than 8 CPUs" 503a0d0bb4dSRandy Dunlap depends on SMP 504a7f7f624SMasahiro Yamada help 505e133f6eaSRandy Dunlap This option is needed for the systems that have more than 8 CPUs. 506a0d0bb4dSRandy Dunlap 507c5c606d9SRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 508c5c606d9SRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 509c5c606d9SRavikiran G Thirumalai default y 510a7f7f624SMasahiro Yamada help 51106ac8346SIngo Molnar If you disable this option then the kernel will only support 51206ac8346SIngo Molnar standard PC platforms. (which covers the vast majority of 51306ac8346SIngo Molnar systems out there.) 51406ac8346SIngo Molnar 5158425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5168425091fSRavikiran G Thirumalai for the following (non-PC) 32 bit x86 platforms: 517cb7b8023SBen Hutchings Goldfish (Android emulator) 5188425091fSRavikiran G Thirumalai AMD Elan 5198425091fSRavikiran G Thirumalai RDC R-321x SoC 5208425091fSRavikiran G Thirumalai SGI 320/540 (Visual Workstation) 52183125a3aSAlessandro Rubini STA2X11-based (e.g. Northville) 5223f4110a4SThomas Gleixner Moorestown MID devices 52306ac8346SIngo Molnar 52406ac8346SIngo Molnar If you have one of these systems, or if you want to build a 52506ac8346SIngo Molnar generic distribution kernel, say Y here - otherwise say N. 526758cd94aSJuerg Haefligerendif # X86_32 52706ac8346SIngo Molnar 5288425091fSRavikiran G Thirumalaiif X86_64 5298425091fSRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 5308425091fSRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 5318425091fSRavikiran G Thirumalai default y 532a7f7f624SMasahiro Yamada help 5338425091fSRavikiran G Thirumalai If you disable this option then the kernel will only support 5348425091fSRavikiran G Thirumalai standard PC platforms. (which covers the vast majority of 5358425091fSRavikiran G Thirumalai systems out there.) 5368425091fSRavikiran G Thirumalai 5378425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5388425091fSRavikiran G Thirumalai for the following (non-PC) 64 bit x86 platforms: 53944b111b5SSteffen Persvold Numascale NumaChip 5408425091fSRavikiran G Thirumalai ScaleMP vSMP 5418425091fSRavikiran G Thirumalai SGI Ultraviolet 5428425091fSRavikiran G Thirumalai 5438425091fSRavikiran G Thirumalai If you have one of these systems, or if you want to build a 5448425091fSRavikiran G Thirumalai generic distribution kernel, say Y here - otherwise say N. 545758cd94aSJuerg Haefligerendif # X86_64 546c5c606d9SRavikiran G Thirumalai# This is an alphabetically sorted list of 64 bit extended platforms 547c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 54844b111b5SSteffen Persvoldconfig X86_NUMACHIP 54944b111b5SSteffen Persvold bool "Numascale NumaChip" 55044b111b5SSteffen Persvold depends on X86_64 55144b111b5SSteffen Persvold depends on X86_EXTENDED_PLATFORM 55244b111b5SSteffen Persvold depends on NUMA 55344b111b5SSteffen Persvold depends on SMP 55444b111b5SSteffen Persvold depends on X86_X2APIC 555f9726bfdSDaniel J Blueman depends on PCI_MMCONFIG 556a7f7f624SMasahiro Yamada help 55744b111b5SSteffen Persvold Adds support for Numascale NumaChip large-SMP systems. Needed to 55844b111b5SSteffen Persvold enable more than ~168 cores. 55944b111b5SSteffen Persvold If you don't have one of these, you should say N here. 56003b48632SNick Piggin 5616a48565eSIngo Molnarconfig X86_VSMP 562c5c606d9SRavikiran G Thirumalai bool "ScaleMP vSMP" 5636276a074SBorislav Petkov select HYPERVISOR_GUEST 5646a48565eSIngo Molnar select PARAVIRT 5656a48565eSIngo Molnar depends on X86_64 && PCI 566c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 567ead91d4bSShai Fultheim depends on SMP 568a7f7f624SMasahiro Yamada help 5696a48565eSIngo Molnar Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 5706a48565eSIngo Molnar supposed to run on these EM64T-based machines. Only choose this option 5716a48565eSIngo Molnar if you have one of these machines. 5726a48565eSIngo Molnar 573c5c606d9SRavikiran G Thirumalaiconfig X86_UV 574c5c606d9SRavikiran G Thirumalai bool "SGI Ultraviolet" 575c5c606d9SRavikiran G Thirumalai depends on X86_64 576c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 57754c28d29SJack Steiner depends on NUMA 5781ecb4ae5SAndrew Morton depends on EFI 579c2209ea5SIngo Molnar depends on KEXEC_CORE 5809d6c26e7SSuresh Siddha depends on X86_X2APIC 5811222e564SIngo Molnar depends on PCI 582a7f7f624SMasahiro Yamada help 583c5c606d9SRavikiran G Thirumalai This option is needed in order to support SGI Ultraviolet systems. 584c5c606d9SRavikiran G Thirumalai If you don't have one of these, you should say N here. 585c5c606d9SRavikiran G Thirumalai 586c5c606d9SRavikiran G Thirumalai# Following is an alphabetically sorted list of 32 bit extended platforms 587c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 588506f1d07SSam Ravnborg 589ddd70cf9SJun Nakajimaconfig X86_GOLDFISH 590ddd70cf9SJun Nakajima bool "Goldfish (Virtual Platform)" 591cb7b8023SBen Hutchings depends on X86_EXTENDED_PLATFORM 592a7f7f624SMasahiro Yamada help 593ddd70cf9SJun Nakajima Enable support for the Goldfish virtual platform used primarily 594ddd70cf9SJun Nakajima for Android development. Unless you are building for the Android 595ddd70cf9SJun Nakajima Goldfish emulator say N here. 596ddd70cf9SJun Nakajima 597c751e17bSThomas Gleixnerconfig X86_INTEL_CE 598c751e17bSThomas Gleixner bool "CE4100 TV platform" 599c751e17bSThomas Gleixner depends on PCI 600c751e17bSThomas Gleixner depends on PCI_GODIRECT 6016084a6e2SJiang Liu depends on X86_IO_APIC 602c751e17bSThomas Gleixner depends on X86_32 603c751e17bSThomas Gleixner depends on X86_EXTENDED_PLATFORM 60437bc9f50SDirk Brandewie select X86_REBOOTFIXUPS 605da6b737bSSebastian Andrzej Siewior select OF 606da6b737bSSebastian Andrzej Siewior select OF_EARLY_FLATTREE 607a7f7f624SMasahiro Yamada help 608c751e17bSThomas Gleixner Select for the Intel CE media processor (CE4100) SOC. 609c751e17bSThomas Gleixner This option compiles in support for the CE4100 SOC for settop 610c751e17bSThomas Gleixner boxes and media devices. 611c751e17bSThomas Gleixner 6124cb9b00fSDavid Cohenconfig X86_INTEL_MID 61343605ef1SAlan Cox bool "Intel MID platform support" 61443605ef1SAlan Cox depends on X86_EXTENDED_PLATFORM 615edc6bc78SDavid Cohen depends on X86_PLATFORM_DEVICES 6161ea7c673SAlan Cox depends on PCI 6173fda5bb4SAndy Shevchenko depends on X86_64 || (PCI_GOANY && X86_32) 6181ea7c673SAlan Cox depends on X86_IO_APIC 6194cb9b00fSDavid Cohen select I2C 6207c9c3a1eSAlan Cox select DW_APB_TIMER 62154b34aa0SMika Westerberg select INTEL_SCU_PCI 622a7f7f624SMasahiro Yamada help 6234cb9b00fSDavid Cohen Select to build a kernel capable of supporting Intel MID (Mobile 6244cb9b00fSDavid Cohen Internet Device) platform systems which do not have the PCI legacy 6254cb9b00fSDavid Cohen interfaces. If you are building for a PC class system say N here. 6261ea7c673SAlan Cox 6274cb9b00fSDavid Cohen Intel MID platforms are based on an Intel processor and chipset which 6284cb9b00fSDavid Cohen consume less power than most of the x86 derivatives. 62943605ef1SAlan Cox 6308bbc2a13SBryan O'Donoghueconfig X86_INTEL_QUARK 6318bbc2a13SBryan O'Donoghue bool "Intel Quark platform support" 6328bbc2a13SBryan O'Donoghue depends on X86_32 6338bbc2a13SBryan O'Donoghue depends on X86_EXTENDED_PLATFORM 6348bbc2a13SBryan O'Donoghue depends on X86_PLATFORM_DEVICES 6358bbc2a13SBryan O'Donoghue depends on X86_TSC 6368bbc2a13SBryan O'Donoghue depends on PCI 6378bbc2a13SBryan O'Donoghue depends on PCI_GOANY 6388bbc2a13SBryan O'Donoghue depends on X86_IO_APIC 6398bbc2a13SBryan O'Donoghue select IOSF_MBI 6408bbc2a13SBryan O'Donoghue select INTEL_IMR 6419ab6eb51SAndy Shevchenko select COMMON_CLK 642a7f7f624SMasahiro Yamada help 6438bbc2a13SBryan O'Donoghue Select to include support for Quark X1000 SoC. 6448bbc2a13SBryan O'Donoghue Say Y here if you have a Quark based system such as the Arduino 6458bbc2a13SBryan O'Donoghue compatible Intel Galileo. 6468bbc2a13SBryan O'Donoghue 6473d48aab1SMika Westerbergconfig X86_INTEL_LPSS 6483d48aab1SMika Westerberg bool "Intel Low Power Subsystem Support" 6495962dd22SSinan Kaya depends on X86 && ACPI && PCI 6503d48aab1SMika Westerberg select COMMON_CLK 6510f531431SMathias Nyman select PINCTRL 652eebb3e8dSAndy Shevchenko select IOSF_MBI 653a7f7f624SMasahiro Yamada help 6543d48aab1SMika Westerberg Select to build support for Intel Low Power Subsystem such as 6553d48aab1SMika Westerberg found on Intel Lynxpoint PCH. Selecting this option enables 6560f531431SMathias Nyman things like clock tree (common clock framework) and pincontrol 6570f531431SMathias Nyman which are needed by the LPSS peripheral drivers. 6583d48aab1SMika Westerberg 65992082a88SKen Xueconfig X86_AMD_PLATFORM_DEVICE 66092082a88SKen Xue bool "AMD ACPI2Platform devices support" 66192082a88SKen Xue depends on ACPI 66292082a88SKen Xue select COMMON_CLK 66392082a88SKen Xue select PINCTRL 664a7f7f624SMasahiro Yamada help 66592082a88SKen Xue Select to interpret AMD specific ACPI device to platform device 66692082a88SKen Xue such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 66792082a88SKen Xue I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 66892082a88SKen Xue implemented under PINCTRL subsystem. 66992082a88SKen Xue 670ced3ce76SDavid E. Boxconfig IOSF_MBI 671ced3ce76SDavid E. Box tristate "Intel SoC IOSF Sideband support for SoC platforms" 672ced3ce76SDavid E. Box depends on PCI 673a7f7f624SMasahiro Yamada help 674ced3ce76SDavid E. Box This option enables sideband register access support for Intel SoC 675ced3ce76SDavid E. Box platforms. On these platforms the IOSF sideband is used in lieu of 676ced3ce76SDavid E. Box MSR's for some register accesses, mostly but not limited to thermal 677ced3ce76SDavid E. Box and power. Drivers may query the availability of this device to 678ced3ce76SDavid E. Box determine if they need the sideband in order to work on these 679ced3ce76SDavid E. Box platforms. The sideband is available on the following SoC products. 680ced3ce76SDavid E. Box This list is not meant to be exclusive. 681ced3ce76SDavid E. Box - BayTrail 682ced3ce76SDavid E. Box - Braswell 683ced3ce76SDavid E. Box - Quark 684ced3ce76SDavid E. Box 685ced3ce76SDavid E. Box You should say Y if you are running a kernel on one of these SoC's. 686ced3ce76SDavid E. Box 687ed2226bdSDavid E. Boxconfig IOSF_MBI_DEBUG 688ed2226bdSDavid E. Box bool "Enable IOSF sideband access through debugfs" 689ed2226bdSDavid E. Box depends on IOSF_MBI && DEBUG_FS 690a7f7f624SMasahiro Yamada help 691ed2226bdSDavid E. Box Select this option to expose the IOSF sideband access registers (MCR, 692ed2226bdSDavid E. Box MDR, MCRX) through debugfs to write and read register information from 693ed2226bdSDavid E. Box different units on the SoC. This is most useful for obtaining device 694ed2226bdSDavid E. Box state information for debug and analysis. As this is a general access 695ed2226bdSDavid E. Box mechanism, users of this option would have specific knowledge of the 696ed2226bdSDavid E. Box device they want to access. 697ed2226bdSDavid E. Box 698ed2226bdSDavid E. Box If you don't require the option or are in doubt, say N. 699ed2226bdSDavid E. Box 700c5c606d9SRavikiran G Thirumalaiconfig X86_RDC321X 701c5c606d9SRavikiran G Thirumalai bool "RDC R-321x SoC" 702506f1d07SSam Ravnborg depends on X86_32 703c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 704c5c606d9SRavikiran G Thirumalai select M486 705c5c606d9SRavikiran G Thirumalai select X86_REBOOTFIXUPS 706a7f7f624SMasahiro Yamada help 707c5c606d9SRavikiran G Thirumalai This option is needed for RDC R-321x system-on-chip, also known 708c5c606d9SRavikiran G Thirumalai as R-8610-(G). 709c5c606d9SRavikiran G Thirumalai If you don't have one of these chips, you should say N here. 710c5c606d9SRavikiran G Thirumalai 711e0c7ae37SIngo Molnarconfig X86_32_NON_STANDARD 7129c398017SIngo Molnar bool "Support non-standard 32-bit SMP architectures" 7139c398017SIngo Molnar depends on X86_32 && SMP 714c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 715a7f7f624SMasahiro Yamada help 716b5660ba7SH. Peter Anvin This option compiles in the bigsmp and STA2X11 default 717b5660ba7SH. Peter Anvin subarchitectures. It is intended for a generic binary 718b5660ba7SH. Peter Anvin kernel. If you select them all, kernel will probe it one by 719b5660ba7SH. Peter Anvin one and will fallback to default. 720d49c4288SYinghai Lu 721c5c606d9SRavikiran G Thirumalai# Alphabetically sorted list of Non standard 32 bit platforms 722d49c4288SYinghai Lu 723d949f36fSLinus Torvaldsconfig X86_SUPPORTS_MEMORY_FAILURE 7246fc108a0SJan Beulich def_bool y 725d949f36fSLinus Torvalds # MCE code calls memory_failure(): 726d949f36fSLinus Torvalds depends on X86_MCE 727d949f36fSLinus Torvalds # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 728d949f36fSLinus Torvalds # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 729d949f36fSLinus Torvalds depends on X86_64 || !SPARSEMEM 730d949f36fSLinus Torvalds select ARCH_SUPPORTS_MEMORY_FAILURE 731d949f36fSLinus Torvalds 73283125a3aSAlessandro Rubiniconfig STA2X11 73383125a3aSAlessandro Rubini bool "STA2X11 Companion Chip Support" 73483125a3aSAlessandro Rubini depends on X86_32_NON_STANDARD && PCI 73583125a3aSAlessandro Rubini select SWIOTLB 73683125a3aSAlessandro Rubini select MFD_STA2X11 7370145071bSLinus Walleij select GPIOLIB 738a7f7f624SMasahiro Yamada help 73983125a3aSAlessandro Rubini This adds support for boards based on the STA2X11 IO-Hub, 74083125a3aSAlessandro Rubini a.k.a. "ConneXt". The chip is used in place of the standard 74183125a3aSAlessandro Rubini PC chipset, so all "standard" peripherals are missing. If this 74283125a3aSAlessandro Rubini option is selected the kernel will still be able to boot on 74383125a3aSAlessandro Rubini standard PC machines. 74483125a3aSAlessandro Rubini 74582148d1dSShérabconfig X86_32_IRIS 74682148d1dSShérab tristate "Eurobraille/Iris poweroff module" 74782148d1dSShérab depends on X86_32 748a7f7f624SMasahiro Yamada help 74982148d1dSShérab The Iris machines from EuroBraille do not have APM or ACPI support 75082148d1dSShérab to shut themselves down properly. A special I/O sequence is 75182148d1dSShérab needed to do so, which is what this module does at 75282148d1dSShérab kernel shutdown. 75382148d1dSShérab 75482148d1dSShérab This is only for Iris machines from EuroBraille. 75582148d1dSShérab 75682148d1dSShérab If unused, say N. 75782148d1dSShérab 758ae1e9130SIngo Molnarconfig SCHED_OMIT_FRAME_POINTER 7593c2362e6SHarvey Harrison def_bool y 7603c2362e6SHarvey Harrison prompt "Single-depth WCHAN output" 761a87d0914SKen Chen depends on X86 762a7f7f624SMasahiro Yamada help 763506f1d07SSam Ravnborg Calculate simpler /proc/<PID>/wchan values. If this option 764506f1d07SSam Ravnborg is disabled then wchan values will recurse back to the 765506f1d07SSam Ravnborg caller function. This provides more accurate wchan values, 766506f1d07SSam Ravnborg at the expense of slightly more scheduling overhead. 767506f1d07SSam Ravnborg 768506f1d07SSam Ravnborg If in doubt, say "Y". 769506f1d07SSam Ravnborg 7706276a074SBorislav Petkovmenuconfig HYPERVISOR_GUEST 7716276a074SBorislav Petkov bool "Linux guest support" 772a7f7f624SMasahiro Yamada help 7736276a074SBorislav Petkov Say Y here to enable options for running Linux under various hyper- 7746276a074SBorislav Petkov visors. This option enables basic hypervisor detection and platform 7756276a074SBorislav Petkov setup. 776506f1d07SSam Ravnborg 7776276a074SBorislav Petkov If you say N, all options in this submenu will be skipped and 7786276a074SBorislav Petkov disabled, and Linux guest support won't be built in. 779506f1d07SSam Ravnborg 7806276a074SBorislav Petkovif HYPERVISOR_GUEST 781506f1d07SSam Ravnborg 782e61bd94aSEduardo Pereira Habkostconfig PARAVIRT 783e61bd94aSEduardo Pereira Habkost bool "Enable paravirtualization code" 784a0e2bf7cSJuergen Gross depends on HAVE_STATIC_CALL 785a7f7f624SMasahiro Yamada help 786e61bd94aSEduardo Pereira Habkost This changes the kernel so it can modify itself when it is run 787e61bd94aSEduardo Pereira Habkost under a hypervisor, potentially improving performance significantly 788e61bd94aSEduardo Pereira Habkost over full virtualization. However, when run without a hypervisor 789e61bd94aSEduardo Pereira Habkost the kernel is theoretically slower and slightly larger. 790e61bd94aSEduardo Pereira Habkost 791c00a280aSJuergen Grossconfig PARAVIRT_XXL 792c00a280aSJuergen Gross bool 793c00a280aSJuergen Gross 7946276a074SBorislav Petkovconfig PARAVIRT_DEBUG 7956276a074SBorislav Petkov bool "paravirt-ops debugging" 7966276a074SBorislav Petkov depends on PARAVIRT && DEBUG_KERNEL 797a7f7f624SMasahiro Yamada help 7986276a074SBorislav Petkov Enable to debug paravirt_ops internals. Specifically, BUG if 7996276a074SBorislav Petkov a paravirt_op is missing when it is called. 8006276a074SBorislav Petkov 801b4ecc126SJeremy Fitzhardingeconfig PARAVIRT_SPINLOCKS 802b4ecc126SJeremy Fitzhardinge bool "Paravirtualization layer for spinlocks" 8036ea30386SKees Cook depends on PARAVIRT && SMP 804a7f7f624SMasahiro Yamada help 805b4ecc126SJeremy Fitzhardinge Paravirtualized spinlocks allow a pvops backend to replace the 806b4ecc126SJeremy Fitzhardinge spinlock implementation with something virtualization-friendly 807b4ecc126SJeremy Fitzhardinge (for example, block the virtual CPU rather than spinning). 808b4ecc126SJeremy Fitzhardinge 8094c4e4f61SRaghavendra K T It has a minimal impact on native kernels and gives a nice performance 8104c4e4f61SRaghavendra K T benefit on paravirtualized KVM / Xen kernels. 811b4ecc126SJeremy Fitzhardinge 8124c4e4f61SRaghavendra K T If you are unsure how to answer this question, answer Y. 813b4ecc126SJeremy Fitzhardinge 814ecca2502SZhao Yakuiconfig X86_HV_CALLBACK_VECTOR 815ecca2502SZhao Yakui def_bool n 816ecca2502SZhao Yakui 8176276a074SBorislav Petkovsource "arch/x86/xen/Kconfig" 8186276a074SBorislav Petkov 8196276a074SBorislav Petkovconfig KVM_GUEST 8206276a074SBorislav Petkov bool "KVM Guest support (including kvmclock)" 8216276a074SBorislav Petkov depends on PARAVIRT 8226276a074SBorislav Petkov select PARAVIRT_CLOCK 823a1c4423bSMarcelo Tosatti select ARCH_CPUIDLE_HALTPOLL 824b1d40575SVitaly Kuznetsov select X86_HV_CALLBACK_VECTOR 8256276a074SBorislav Petkov default y 826a7f7f624SMasahiro Yamada help 8276276a074SBorislav Petkov This option enables various optimizations for running under the KVM 8286276a074SBorislav Petkov hypervisor. It includes a paravirtualized clock, so that instead 8296276a074SBorislav Petkov of relying on a PIT (or probably other) emulation by the 8306276a074SBorislav Petkov underlying device model, the host provides the guest with 8316276a074SBorislav Petkov timing infrastructure such as time of day, and system time 8326276a074SBorislav Petkov 833a1c4423bSMarcelo Tosatticonfig ARCH_CPUIDLE_HALTPOLL 834a1c4423bSMarcelo Tosatti def_bool n 835a1c4423bSMarcelo Tosatti prompt "Disable host haltpoll when loading haltpoll driver" 836a1c4423bSMarcelo Tosatti help 837a1c4423bSMarcelo Tosatti If virtualized under KVM, disable host haltpoll. 838a1c4423bSMarcelo Tosatti 8397733607fSMaran Wilsonconfig PVH 8407733607fSMaran Wilson bool "Support for running PVH guests" 841a7f7f624SMasahiro Yamada help 8427733607fSMaran Wilson This option enables the PVH entry point for guest virtual machines 8437733607fSMaran Wilson as specified in the x86/HVM direct boot ABI. 8447733607fSMaran Wilson 8456276a074SBorislav Petkovconfig PARAVIRT_TIME_ACCOUNTING 8466276a074SBorislav Petkov bool "Paravirtual steal time accounting" 8476276a074SBorislav Petkov depends on PARAVIRT 848a7f7f624SMasahiro Yamada help 8496276a074SBorislav Petkov Select this option to enable fine granularity task steal time 8506276a074SBorislav Petkov accounting. Time spent executing other tasks in parallel with 8516276a074SBorislav Petkov the current vCPU is discounted from the vCPU power. To account for 8526276a074SBorislav Petkov that, there can be a small performance impact. 8536276a074SBorislav Petkov 8546276a074SBorislav Petkov If in doubt, say N here. 8556276a074SBorislav Petkov 8567af192c9SGerd Hoffmannconfig PARAVIRT_CLOCK 8577af192c9SGerd Hoffmann bool 8587af192c9SGerd Hoffmann 8594a362601SJan Kiszkaconfig JAILHOUSE_GUEST 8604a362601SJan Kiszka bool "Jailhouse non-root cell support" 861abde587bSArnd Bergmann depends on X86_64 && PCI 86287e65d05SJan Kiszka select X86_PM_TIMER 863a7f7f624SMasahiro Yamada help 8644a362601SJan Kiszka This option allows to run Linux as guest in a Jailhouse non-root 8654a362601SJan Kiszka cell. You can leave this option disabled if you only want to start 8664a362601SJan Kiszka Jailhouse and run Linux afterwards in the root cell. 8674a362601SJan Kiszka 868ec7972c9SZhao Yakuiconfig ACRN_GUEST 869ec7972c9SZhao Yakui bool "ACRN Guest support" 870ec7972c9SZhao Yakui depends on X86_64 871498ad393SZhao Yakui select X86_HV_CALLBACK_VECTOR 872ec7972c9SZhao Yakui help 873ec7972c9SZhao Yakui This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 874ec7972c9SZhao Yakui a flexible, lightweight reference open-source hypervisor, built with 875ec7972c9SZhao Yakui real-time and safety-criticality in mind. It is built for embedded 876ec7972c9SZhao Yakui IOT with small footprint and real-time features. More details can be 877ec7972c9SZhao Yakui found in https://projectacrn.org/. 878ec7972c9SZhao Yakui 87959bd54a8SKuppuswamy Sathyanarayananconfig INTEL_TDX_GUEST 88059bd54a8SKuppuswamy Sathyanarayanan bool "Intel TDX (Trust Domain Extensions) - Guest Support" 88159bd54a8SKuppuswamy Sathyanarayanan depends on X86_64 && CPU_SUP_INTEL 88259bd54a8SKuppuswamy Sathyanarayanan depends on X86_X2APIC 88375d090fdSKirill A. Shutemov depends on EFI_STUB 88441394e33SKirill A. Shutemov select ARCH_HAS_CC_PLATFORM 885968b4931SKirill A. Shutemov select X86_MEM_ENCRYPT 88677a512e3SSean Christopherson select X86_MCE 88775d090fdSKirill A. Shutemov select UNACCEPTED_MEMORY 88859bd54a8SKuppuswamy Sathyanarayanan help 88959bd54a8SKuppuswamy Sathyanarayanan Support running as a guest under Intel TDX. Without this support, 89059bd54a8SKuppuswamy Sathyanarayanan the guest kernel can not boot or run under TDX. 89159bd54a8SKuppuswamy Sathyanarayanan TDX includes memory encryption and integrity capabilities 89259bd54a8SKuppuswamy Sathyanarayanan which protect the confidentiality and integrity of guest 89359bd54a8SKuppuswamy Sathyanarayanan memory contents and CPU state. TDX guests are protected from 89459bd54a8SKuppuswamy Sathyanarayanan some attacks from the VMM. 89559bd54a8SKuppuswamy Sathyanarayanan 8966276a074SBorislav Petkovendif # HYPERVISOR_GUEST 89797349135SJeremy Fitzhardinge 898506f1d07SSam Ravnborgsource "arch/x86/Kconfig.cpu" 899506f1d07SSam Ravnborg 900506f1d07SSam Ravnborgconfig HPET_TIMER 9013c2362e6SHarvey Harrison def_bool X86_64 902506f1d07SSam Ravnborg prompt "HPET Timer Support" if X86_32 903a7f7f624SMasahiro Yamada help 904506f1d07SSam Ravnborg Use the IA-PC HPET (High Precision Event Timer) to manage 905506f1d07SSam Ravnborg time in preference to the PIT and RTC, if a HPET is 906506f1d07SSam Ravnborg present. 907506f1d07SSam Ravnborg HPET is the next generation timer replacing legacy 8254s. 908506f1d07SSam Ravnborg The HPET provides a stable time base on SMP 909506f1d07SSam Ravnborg systems, unlike the TSC, but it is more expensive to access, 9104e7f9df2SMichael S. Tsirkin as it is off-chip. The interface used is documented 9114e7f9df2SMichael S. Tsirkin in the HPET spec, revision 1. 912506f1d07SSam Ravnborg 913506f1d07SSam Ravnborg You can safely choose Y here. However, HPET will only be 914506f1d07SSam Ravnborg activated if the platform and the BIOS support this feature. 915506f1d07SSam Ravnborg Otherwise the 8254 will be used for timing services. 916506f1d07SSam Ravnborg 917506f1d07SSam Ravnborg Choose N to continue using the legacy 8254 timer. 918506f1d07SSam Ravnborg 919506f1d07SSam Ravnborgconfig HPET_EMULATE_RTC 9203c2362e6SHarvey Harrison def_bool y 9213228e1dcSAnand K Mistry depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 922506f1d07SSam Ravnborg 9236a108a14SDavid Rientjes# Mark as expert because too many people got it wrong. 924506f1d07SSam Ravnborg# The code disables itself when not needed. 9257ae9392cSThomas Petazzoniconfig DMI 9267ae9392cSThomas Petazzoni default y 927cf074402SArd Biesheuvel select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 9286a108a14SDavid Rientjes bool "Enable DMI scanning" if EXPERT 929a7f7f624SMasahiro Yamada help 9307ae9392cSThomas Petazzoni Enabled scanning of DMI to identify machine quirks. Say Y 9317ae9392cSThomas Petazzoni here unless you have verified that your setup is not 9327ae9392cSThomas Petazzoni affected by entries in the DMI blacklist. Required by PNP 9337ae9392cSThomas Petazzoni BIOS code. 9347ae9392cSThomas Petazzoni 935506f1d07SSam Ravnborgconfig GART_IOMMU 93638901f1cSAndi Kleen bool "Old AMD GART IOMMU support" 9372f9237d4SChristoph Hellwig select DMA_OPS 938a4ce5a48SChristoph Hellwig select IOMMU_HELPER 939506f1d07SSam Ravnborg select SWIOTLB 94023ac4ae8SAndreas Herrmann depends on X86_64 && PCI && AMD_NB 941a7f7f624SMasahiro Yamada help 942ced3c42cSIngo Molnar Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 943ced3c42cSIngo Molnar GART based hardware IOMMUs. 944ced3c42cSIngo Molnar 945ced3c42cSIngo Molnar The GART supports full DMA access for devices with 32-bit access 946ced3c42cSIngo Molnar limitations, on systems with more than 3 GB. This is usually needed 947ced3c42cSIngo Molnar for USB, sound, many IDE/SATA chipsets and some other devices. 948ced3c42cSIngo Molnar 949ced3c42cSIngo Molnar Newer systems typically have a modern AMD IOMMU, supported via 950ced3c42cSIngo Molnar the CONFIG_AMD_IOMMU=y config option. 951ced3c42cSIngo Molnar 952ced3c42cSIngo Molnar In normal configurations this driver is only active when needed: 953ced3c42cSIngo Molnar there's more than 3 GB of memory and the system contains a 954ced3c42cSIngo Molnar 32-bit limited device. 955ced3c42cSIngo Molnar 956ced3c42cSIngo Molnar If unsure, say Y. 957506f1d07SSam Ravnborg 9588b766b0fSMichal Suchanekconfig BOOT_VESA_SUPPORT 9598b766b0fSMichal Suchanek bool 9608b766b0fSMichal Suchanek help 9618b766b0fSMichal Suchanek If true, at least one selected framebuffer driver can take advantage 9628b766b0fSMichal Suchanek of VESA video modes set at an early boot stage via the vga= parameter. 9638b766b0fSMichal Suchanek 9641184dc2fSMike Travisconfig MAXSMP 965ddb0c5a6SSamuel Thibault bool "Enable Maximum number of SMP Processors and NUMA Nodes" 9666ea30386SKees Cook depends on X86_64 && SMP && DEBUG_KERNEL 96736f5101aSMike Travis select CPUMASK_OFFSTACK 968a7f7f624SMasahiro Yamada help 969ddb0c5a6SSamuel Thibault Enable maximum number of CPUS and NUMA Nodes for this architecture. 9701184dc2fSMike Travis If unsure, say N. 971506f1d07SSam Ravnborg 972aec6487eSIngo Molnar# 973aec6487eSIngo Molnar# The maximum number of CPUs supported: 974aec6487eSIngo Molnar# 975aec6487eSIngo Molnar# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 976aec6487eSIngo Molnar# and which can be configured interactively in the 977aec6487eSIngo Molnar# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 978aec6487eSIngo Molnar# 979aec6487eSIngo Molnar# The ranges are different on 32-bit and 64-bit kernels, depending on 980aec6487eSIngo Molnar# hardware capabilities and scalability features of the kernel. 981aec6487eSIngo Molnar# 982aec6487eSIngo Molnar# ( If MAXSMP is enabled we just use the highest possible value and disable 983aec6487eSIngo Molnar# interactive configuration. ) 984aec6487eSIngo Molnar# 985a0d0bb4dSRandy Dunlap 986aec6487eSIngo Molnarconfig NR_CPUS_RANGE_BEGIN 987a0d0bb4dSRandy Dunlap int 988aec6487eSIngo Molnar default NR_CPUS_RANGE_END if MAXSMP 989a0d0bb4dSRandy Dunlap default 1 if !SMP 990a0d0bb4dSRandy Dunlap default 2 991a0d0bb4dSRandy Dunlap 992aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 993a0d0bb4dSRandy Dunlap int 994a0d0bb4dSRandy Dunlap depends on X86_32 995aec6487eSIngo Molnar default 64 if SMP && X86_BIGSMP 996aec6487eSIngo Molnar default 8 if SMP && !X86_BIGSMP 997a0d0bb4dSRandy Dunlap default 1 if !SMP 998a0d0bb4dSRandy Dunlap 999aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 1000a0d0bb4dSRandy Dunlap int 1001a0d0bb4dSRandy Dunlap depends on X86_64 10021edae1aeSScott Wood default 8192 if SMP && CPUMASK_OFFSTACK 10031edae1aeSScott Wood default 512 if SMP && !CPUMASK_OFFSTACK 1004a0d0bb4dSRandy Dunlap default 1 if !SMP 1005aec6487eSIngo Molnar 1006aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 1007aec6487eSIngo Molnar int 1008aec6487eSIngo Molnar depends on X86_32 1009aec6487eSIngo Molnar default 32 if X86_BIGSMP 1010aec6487eSIngo Molnar default 8 if SMP 1011aec6487eSIngo Molnar default 1 if !SMP 1012aec6487eSIngo Molnar 1013aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 1014aec6487eSIngo Molnar int 1015aec6487eSIngo Molnar depends on X86_64 1016a0d0bb4dSRandy Dunlap default 8192 if MAXSMP 1017a0d0bb4dSRandy Dunlap default 64 if SMP 1018aec6487eSIngo Molnar default 1 if !SMP 1019a0d0bb4dSRandy Dunlap 1020506f1d07SSam Ravnborgconfig NR_CPUS 102136f5101aSMike Travis int "Maximum number of CPUs" if SMP && !MAXSMP 1022aec6487eSIngo Molnar range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1023aec6487eSIngo Molnar default NR_CPUS_DEFAULT 1024a7f7f624SMasahiro Yamada help 1025506f1d07SSam Ravnborg This allows you to specify the maximum number of CPUs which this 1026bb61ccc7SJosh Boyer kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1027cad14bb9SKirill A. Shutemov supported value is 8192, otherwise the maximum value is 512. The 1028506f1d07SSam Ravnborg minimum value which makes sense is 2. 1029506f1d07SSam Ravnborg 1030aec6487eSIngo Molnar This is purely to save memory: each supported CPU adds about 8KB 1031aec6487eSIngo Molnar to the kernel image. 1032506f1d07SSam Ravnborg 103366558b73STim Chenconfig SCHED_CLUSTER 103466558b73STim Chen bool "Cluster scheduler support" 103566558b73STim Chen depends on SMP 103666558b73STim Chen default y 103766558b73STim Chen help 103866558b73STim Chen Cluster scheduler support improves the CPU scheduler's decision 103966558b73STim Chen making when dealing with machines that have clusters of CPUs. 104066558b73STim Chen Cluster usually means a couple of CPUs which are placed closely 104166558b73STim Chen by sharing mid-level caches, last-level cache tags or internal 104266558b73STim Chen busses. 104366558b73STim Chen 1044506f1d07SSam Ravnborgconfig SCHED_SMT 1045dbe73364SThomas Gleixner def_bool y if SMP 1046506f1d07SSam Ravnborg 1047506f1d07SSam Ravnborgconfig SCHED_MC 10483c2362e6SHarvey Harrison def_bool y 10493c2362e6SHarvey Harrison prompt "Multi-core scheduler support" 1050c8e56d20SBorislav Petkov depends on SMP 1051a7f7f624SMasahiro Yamada help 1052506f1d07SSam Ravnborg Multi-core scheduler support improves the CPU scheduler's decision 1053506f1d07SSam Ravnborg making when dealing with multi-core CPU chips at a cost of slightly 1054506f1d07SSam Ravnborg increased overhead in some places. If unsure say N here. 1055506f1d07SSam Ravnborg 1056de966cf4STim Chenconfig SCHED_MC_PRIO 1057de966cf4STim Chen bool "CPU core priorities scheduler support" 10580a21fc12SIngo Molnar depends on SCHED_MC && CPU_SUP_INTEL 10590a21fc12SIngo Molnar select X86_INTEL_PSTATE 10600a21fc12SIngo Molnar select CPU_FREQ 1061de966cf4STim Chen default y 1062a7f7f624SMasahiro Yamada help 1063de966cf4STim Chen Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1064de966cf4STim Chen core ordering determined at manufacturing time, which allows 1065de966cf4STim Chen certain cores to reach higher turbo frequencies (when running 1066de966cf4STim Chen single threaded workloads) than others. 1067de966cf4STim Chen 1068de966cf4STim Chen Enabling this kernel feature teaches the scheduler about 1069de966cf4STim Chen the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1070de966cf4STim Chen scheduler's CPU selection logic accordingly, so that higher 1071de966cf4STim Chen overall system performance can be achieved. 1072de966cf4STim Chen 1073de966cf4STim Chen This feature will have no effect on CPUs without this feature. 1074de966cf4STim Chen 1075de966cf4STim Chen If unsure say Y here. 10765e76b2abSTim Chen 107730b8b006SThomas Gleixnerconfig UP_LATE_INIT 107830b8b006SThomas Gleixner def_bool y 1079ba360f88SThomas Gleixner depends on !SMP && X86_LOCAL_APIC 108030b8b006SThomas Gleixner 1081506f1d07SSam Ravnborgconfig X86_UP_APIC 108250849eefSJan Beulich bool "Local APIC support on uniprocessors" if !PCI_MSI 108350849eefSJan Beulich default PCI_MSI 108438a1dfdaSBryan O'Donoghue depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1085a7f7f624SMasahiro Yamada help 1086506f1d07SSam Ravnborg A local APIC (Advanced Programmable Interrupt Controller) is an 1087506f1d07SSam Ravnborg integrated interrupt controller in the CPU. If you have a single-CPU 1088506f1d07SSam Ravnborg system which has a processor with a local APIC, you can say Y here to 1089506f1d07SSam Ravnborg enable and use it. If you say Y here even though your machine doesn't 1090506f1d07SSam Ravnborg have a local APIC, then the kernel will still run with no slowdown at 1091506f1d07SSam Ravnborg all. The local APIC supports CPU-generated self-interrupts (timer, 1092506f1d07SSam Ravnborg performance counters), and the NMI watchdog which detects hard 1093506f1d07SSam Ravnborg lockups. 1094506f1d07SSam Ravnborg 1095506f1d07SSam Ravnborgconfig X86_UP_IOAPIC 1096506f1d07SSam Ravnborg bool "IO-APIC support on uniprocessors" 1097506f1d07SSam Ravnborg depends on X86_UP_APIC 1098a7f7f624SMasahiro Yamada help 1099506f1d07SSam Ravnborg An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1100506f1d07SSam Ravnborg SMP-capable replacement for PC-style interrupt controllers. Most 1101506f1d07SSam Ravnborg SMP systems and many recent uniprocessor systems have one. 1102506f1d07SSam Ravnborg 1103506f1d07SSam Ravnborg If you have a single-CPU system with an IO-APIC, you can say Y here 1104506f1d07SSam Ravnborg to use it. If you say Y here even though your machine doesn't have 1105506f1d07SSam Ravnborg an IO-APIC, then the kernel will still run with no slowdown at all. 1106506f1d07SSam Ravnborg 1107506f1d07SSam Ravnborgconfig X86_LOCAL_APIC 11083c2362e6SHarvey Harrison def_bool y 11090dbc6078SThomas Petazzoni depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1110b5dc8e6cSJiang Liu select IRQ_DOMAIN_HIERARCHY 1111506f1d07SSam Ravnborg 1112506f1d07SSam Ravnborgconfig X86_IO_APIC 1113b1da1e71SJan Beulich def_bool y 1114b1da1e71SJan Beulich depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1115506f1d07SSam Ravnborg 111641b9eb26SStefan Assmannconfig X86_REROUTE_FOR_BROKEN_BOOT_IRQS 111741b9eb26SStefan Assmann bool "Reroute for broken boot IRQs" 111841b9eb26SStefan Assmann depends on X86_IO_APIC 1119a7f7f624SMasahiro Yamada help 112041b9eb26SStefan Assmann This option enables a workaround that fixes a source of 112141b9eb26SStefan Assmann spurious interrupts. This is recommended when threaded 112241b9eb26SStefan Assmann interrupt handling is used on systems where the generation of 112341b9eb26SStefan Assmann superfluous "boot interrupts" cannot be disabled. 112441b9eb26SStefan Assmann 112541b9eb26SStefan Assmann Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 112641b9eb26SStefan Assmann entry in the chipset's IO-APIC is masked (as, e.g. the RT 112741b9eb26SStefan Assmann kernel does during interrupt handling). On chipsets where this 112841b9eb26SStefan Assmann boot IRQ generation cannot be disabled, this workaround keeps 112941b9eb26SStefan Assmann the original IRQ line masked so that only the equivalent "boot 113041b9eb26SStefan Assmann IRQ" is delivered to the CPUs. The workaround also tells the 113141b9eb26SStefan Assmann kernel to set up the IRQ handler on the boot IRQ line. In this 113241b9eb26SStefan Assmann way only one interrupt is delivered to the kernel. Otherwise 113341b9eb26SStefan Assmann the spurious second interrupt may cause the kernel to bring 113441b9eb26SStefan Assmann down (vital) interrupt lines. 113541b9eb26SStefan Assmann 113641b9eb26SStefan Assmann Only affects "broken" chipsets. Interrupt sharing may be 113741b9eb26SStefan Assmann increased on these systems. 113841b9eb26SStefan Assmann 1139506f1d07SSam Ravnborgconfig X86_MCE 1140bab9bc65SAndi Kleen bool "Machine Check / overheating reporting" 1141648ed940SChen, Gong select GENERIC_ALLOCATOR 1142e57dbaf7SBorislav Petkov default y 1143a7f7f624SMasahiro Yamada help 1144bab9bc65SAndi Kleen Machine Check support allows the processor to notify the 1145bab9bc65SAndi Kleen kernel if it detects a problem (e.g. overheating, data corruption). 1146506f1d07SSam Ravnborg The action the kernel takes depends on the severity of the problem, 1147bab9bc65SAndi Kleen ranging from warning messages to halting the machine. 11484efc0670SAndi Kleen 11495de97c9fSTony Luckconfig X86_MCELOG_LEGACY 11505de97c9fSTony Luck bool "Support for deprecated /dev/mcelog character device" 11515de97c9fSTony Luck depends on X86_MCE 1152a7f7f624SMasahiro Yamada help 11535de97c9fSTony Luck Enable support for /dev/mcelog which is needed by the old mcelog 11545de97c9fSTony Luck userspace logging daemon. Consider switching to the new generation 11555de97c9fSTony Luck rasdaemon solution. 11565de97c9fSTony Luck 1157506f1d07SSam Ravnborgconfig X86_MCE_INTEL 11583c2362e6SHarvey Harrison def_bool y 11593c2362e6SHarvey Harrison prompt "Intel MCE features" 1160c1ebf835SAndi Kleen depends on X86_MCE && X86_LOCAL_APIC 1161a7f7f624SMasahiro Yamada help 1162506f1d07SSam Ravnborg Additional support for intel specific MCE features such as 1163506f1d07SSam Ravnborg the thermal monitor. 1164506f1d07SSam Ravnborg 1165506f1d07SSam Ravnborgconfig X86_MCE_AMD 11663c2362e6SHarvey Harrison def_bool y 11673c2362e6SHarvey Harrison prompt "AMD MCE features" 1168f5382de9SYazen Ghannam depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1169a7f7f624SMasahiro Yamada help 1170506f1d07SSam Ravnborg Additional support for AMD specific MCE features such as 1171506f1d07SSam Ravnborg the DRAM Error Threshold. 1172506f1d07SSam Ravnborg 11734efc0670SAndi Kleenconfig X86_ANCIENT_MCE 11746fc108a0SJan Beulich bool "Support for old Pentium 5 / WinChip machine checks" 1175c31d9633SAndi Kleen depends on X86_32 && X86_MCE 1176a7f7f624SMasahiro Yamada help 11774efc0670SAndi Kleen Include support for machine check handling on old Pentium 5 or WinChip 11785065a706SMasanari Iida systems. These typically need to be enabled explicitly on the command 11794efc0670SAndi Kleen line. 11804efc0670SAndi Kleen 1181b2762686SAndi Kleenconfig X86_MCE_THRESHOLD 1182b2762686SAndi Kleen depends on X86_MCE_AMD || X86_MCE_INTEL 11836fc108a0SJan Beulich def_bool y 1184b2762686SAndi Kleen 1185ea149b36SAndi Kleenconfig X86_MCE_INJECT 1186bc8e80d5SBorislav Petkov depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1187ea149b36SAndi Kleen tristate "Machine check injector support" 1188a7f7f624SMasahiro Yamada help 1189ea149b36SAndi Kleen Provide support for injecting machine checks for testing purposes. 1190ea149b36SAndi Kleen If you don't know what a machine check is and you don't do kernel 1191ea149b36SAndi Kleen QA it is safe to say n. 1192ea149b36SAndi Kleen 119307dc900eSPeter Zijlstrasource "arch/x86/events/Kconfig" 1194e633c65aSKan Liang 11955aef51c3SAndy Lutomirskiconfig X86_LEGACY_VM86 11961e642812SIngo Molnar bool "Legacy VM86 support" 1197506f1d07SSam Ravnborg depends on X86_32 1198a7f7f624SMasahiro Yamada help 11995aef51c3SAndy Lutomirski This option allows user programs to put the CPU into V8086 12005aef51c3SAndy Lutomirski mode, which is an 80286-era approximation of 16-bit real mode. 12015aef51c3SAndy Lutomirski 12025aef51c3SAndy Lutomirski Some very old versions of X and/or vbetool require this option 12035aef51c3SAndy Lutomirski for user mode setting. Similarly, DOSEMU will use it if 12045aef51c3SAndy Lutomirski available to accelerate real mode DOS programs. However, any 12055aef51c3SAndy Lutomirski recent version of DOSEMU, X, or vbetool should be fully 12065aef51c3SAndy Lutomirski functional even without kernel VM86 support, as they will all 12071e642812SIngo Molnar fall back to software emulation. Nevertheless, if you are using 12081e642812SIngo Molnar a 16-bit DOS program where 16-bit performance matters, vm86 12091e642812SIngo Molnar mode might be faster than emulation and you might want to 12101e642812SIngo Molnar enable this option. 12115aef51c3SAndy Lutomirski 12121e642812SIngo Molnar Note that any app that works on a 64-bit kernel is unlikely to 12131e642812SIngo Molnar need this option, as 64-bit kernels don't, and can't, support 12141e642812SIngo Molnar V8086 mode. This option is also unrelated to 16-bit protected 12151e642812SIngo Molnar mode and is not needed to run most 16-bit programs under Wine. 12165aef51c3SAndy Lutomirski 12171e642812SIngo Molnar Enabling this option increases the complexity of the kernel 12181e642812SIngo Molnar and slows down exception handling a tiny bit. 12195aef51c3SAndy Lutomirski 12201e642812SIngo Molnar If unsure, say N here. 12215aef51c3SAndy Lutomirski 12225aef51c3SAndy Lutomirskiconfig VM86 12235aef51c3SAndy Lutomirski bool 12245aef51c3SAndy Lutomirski default X86_LEGACY_VM86 122534273f41SH. Peter Anvin 122634273f41SH. Peter Anvinconfig X86_16BIT 122734273f41SH. Peter Anvin bool "Enable support for 16-bit segments" if EXPERT 122834273f41SH. Peter Anvin default y 1229a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 1230a7f7f624SMasahiro Yamada help 123134273f41SH. Peter Anvin This option is required by programs like Wine to run 16-bit 123234273f41SH. Peter Anvin protected mode legacy code on x86 processors. Disabling 123334273f41SH. Peter Anvin this option saves about 300 bytes on i386, or around 6K text 123434273f41SH. Peter Anvin plus 16K runtime memory on x86-64, 123534273f41SH. Peter Anvin 123634273f41SH. Peter Anvinconfig X86_ESPFIX32 123734273f41SH. Peter Anvin def_bool y 123834273f41SH. Peter Anvin depends on X86_16BIT && X86_32 1239506f1d07SSam Ravnborg 1240197725deSH. Peter Anvinconfig X86_ESPFIX64 1241197725deSH. Peter Anvin def_bool y 124234273f41SH. Peter Anvin depends on X86_16BIT && X86_64 1243506f1d07SSam Ravnborg 12441ad83c85SAndy Lutomirskiconfig X86_VSYSCALL_EMULATION 12451ad83c85SAndy Lutomirski bool "Enable vsyscall emulation" if EXPERT 12461ad83c85SAndy Lutomirski default y 12471ad83c85SAndy Lutomirski depends on X86_64 1248a7f7f624SMasahiro Yamada help 12491ad83c85SAndy Lutomirski This enables emulation of the legacy vsyscall page. Disabling 12501ad83c85SAndy Lutomirski it is roughly equivalent to booting with vsyscall=none, except 12511ad83c85SAndy Lutomirski that it will also disable the helpful warning if a program 12521ad83c85SAndy Lutomirski tries to use a vsyscall. With this option set to N, offending 12531ad83c85SAndy Lutomirski programs will just segfault, citing addresses of the form 12541ad83c85SAndy Lutomirski 0xffffffffff600?00. 12551ad83c85SAndy Lutomirski 12561ad83c85SAndy Lutomirski This option is required by many programs built before 2013, and 12571ad83c85SAndy Lutomirski care should be used even with newer programs if set to N. 12581ad83c85SAndy Lutomirski 12591ad83c85SAndy Lutomirski Disabling this option saves about 7K of kernel size and 12601ad83c85SAndy Lutomirski possibly 4K of additional runtime pagetable memory. 12611ad83c85SAndy Lutomirski 1262111e7b15SThomas Gleixnerconfig X86_IOPL_IOPERM 1263111e7b15SThomas Gleixner bool "IOPERM and IOPL Emulation" 1264a24ca997SThomas Gleixner default y 1265a7f7f624SMasahiro Yamada help 1266111e7b15SThomas Gleixner This enables the ioperm() and iopl() syscalls which are necessary 1267111e7b15SThomas Gleixner for legacy applications. 1268111e7b15SThomas Gleixner 1269c8137aceSThomas Gleixner Legacy IOPL support is an overbroad mechanism which allows user 1270c8137aceSThomas Gleixner space aside of accessing all 65536 I/O ports also to disable 1271c8137aceSThomas Gleixner interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1272c8137aceSThomas Gleixner capabilities and permission from potentially active security 1273c8137aceSThomas Gleixner modules. 1274c8137aceSThomas Gleixner 1275c8137aceSThomas Gleixner The emulation restricts the functionality of the syscall to 1276c8137aceSThomas Gleixner only allowing the full range I/O port access, but prevents the 1277a24ca997SThomas Gleixner ability to disable interrupts from user space which would be 1278a24ca997SThomas Gleixner granted if the hardware IOPL mechanism would be used. 1279c8137aceSThomas Gleixner 1280506f1d07SSam Ravnborgconfig TOSHIBA 1281506f1d07SSam Ravnborg tristate "Toshiba Laptop support" 1282506f1d07SSam Ravnborg depends on X86_32 1283a7f7f624SMasahiro Yamada help 1284506f1d07SSam Ravnborg This adds a driver to safely access the System Management Mode of 1285506f1d07SSam Ravnborg the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1286506f1d07SSam Ravnborg not work on models with a Phoenix BIOS. The System Management Mode 1287506f1d07SSam Ravnborg is used to set the BIOS and power saving options on Toshiba portables. 1288506f1d07SSam Ravnborg 1289506f1d07SSam Ravnborg For information on utilities to make use of this driver see the 1290506f1d07SSam Ravnborg Toshiba Linux utilities web site at: 1291506f1d07SSam Ravnborg <http://www.buzzard.org.uk/toshiba/>. 1292506f1d07SSam Ravnborg 1293506f1d07SSam Ravnborg Say Y if you intend to run this kernel on a Toshiba portable. 1294506f1d07SSam Ravnborg Say N otherwise. 1295506f1d07SSam Ravnborg 1296506f1d07SSam Ravnborgconfig X86_REBOOTFIXUPS 12979ba16087SJan Beulich bool "Enable X86 board specific fixups for reboot" 12989ba16087SJan Beulich depends on X86_32 1299a7f7f624SMasahiro Yamada help 1300506f1d07SSam Ravnborg This enables chipset and/or board specific fixups to be done 1301506f1d07SSam Ravnborg in order to get reboot to work correctly. This is only needed on 1302506f1d07SSam Ravnborg some combinations of hardware and BIOS. The symptom, for which 1303506f1d07SSam Ravnborg this config is intended, is when reboot ends with a stalled/hung 1304506f1d07SSam Ravnborg system. 1305506f1d07SSam Ravnborg 1306506f1d07SSam Ravnborg Currently, the only fixup is for the Geode machines using 13075e3a77e9SFlorian Fainelli CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1308506f1d07SSam Ravnborg 1309506f1d07SSam Ravnborg Say Y if you want to enable the fixup. Currently, it's safe to 1310506f1d07SSam Ravnborg enable this option even if you don't need it. 1311506f1d07SSam Ravnborg Say N otherwise. 1312506f1d07SSam Ravnborg 1313506f1d07SSam Ravnborgconfig MICROCODE 1314e6bcfdd7SThomas Gleixner def_bool y 131580030e3dSBorislav Petkov depends on CPU_SUP_AMD || CPU_SUP_INTEL 131680cc9f10SPeter Oruba 1317fdbd4381SThomas Gleixnerconfig MICROCODE_INITRD32 1318fdbd4381SThomas Gleixner def_bool y 1319fdbd4381SThomas Gleixner depends on MICROCODE && X86_32 && BLK_DEV_INITRD 1320fdbd4381SThomas Gleixner 1321a77a94f8SBorislav Petkovconfig MICROCODE_LATE_LOADING 1322a77a94f8SBorislav Petkov bool "Late microcode loading (DANGEROUS)" 1323c02f48e0SBorislav Petkov default n 1324634ac23aSThomas Gleixner depends on MICROCODE && SMP 1325a7f7f624SMasahiro Yamada help 1326a77a94f8SBorislav Petkov Loading microcode late, when the system is up and executing instructions 1327a77a94f8SBorislav Petkov is a tricky business and should be avoided if possible. Just the sequence 1328a77a94f8SBorislav Petkov of synchronizing all cores and SMT threads is one fragile dance which does 1329a77a94f8SBorislav Petkov not guarantee that cores might not softlock after the loading. Therefore, 13309407bda8SThomas Gleixner use this at your own risk. Late loading taints the kernel unless the 13319407bda8SThomas Gleixner microcode header indicates that it is safe for late loading via the 13329407bda8SThomas Gleixner minimal revision check. This minimal revision check can be enforced on 13339407bda8SThomas Gleixner the kernel command line with "microcode.minrev=Y". 13349407bda8SThomas Gleixner 13359407bda8SThomas Gleixnerconfig MICROCODE_LATE_FORCE_MINREV 13369407bda8SThomas Gleixner bool "Enforce late microcode loading minimal revision check" 13379407bda8SThomas Gleixner default n 13389407bda8SThomas Gleixner depends on MICROCODE_LATE_LOADING 13399407bda8SThomas Gleixner help 13409407bda8SThomas Gleixner To prevent that users load microcode late which modifies already 13419407bda8SThomas Gleixner in use features, newer microcode patches have a minimum revision field 13429407bda8SThomas Gleixner in the microcode header, which tells the kernel which minimum 13439407bda8SThomas Gleixner revision must be active in the CPU to safely load that new microcode 13449407bda8SThomas Gleixner late into the running system. If disabled the check will not 13459407bda8SThomas Gleixner be enforced but the kernel will be tainted when the minimal 13469407bda8SThomas Gleixner revision check fails. 13479407bda8SThomas Gleixner 13489407bda8SThomas Gleixner This minimal revision check can also be controlled via the 13499407bda8SThomas Gleixner "microcode.minrev" parameter on the kernel command line. 13509407bda8SThomas Gleixner 13519407bda8SThomas Gleixner If unsure say Y. 1352506f1d07SSam Ravnborg 1353506f1d07SSam Ravnborgconfig X86_MSR 1354506f1d07SSam Ravnborg tristate "/dev/cpu/*/msr - Model-specific register support" 1355a7f7f624SMasahiro Yamada help 1356506f1d07SSam Ravnborg This device gives privileged processes access to the x86 1357506f1d07SSam Ravnborg Model-Specific Registers (MSRs). It is a character device with 1358506f1d07SSam Ravnborg major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1359506f1d07SSam Ravnborg MSR accesses are directed to a specific CPU on multi-processor 1360506f1d07SSam Ravnborg systems. 1361506f1d07SSam Ravnborg 1362506f1d07SSam Ravnborgconfig X86_CPUID 1363506f1d07SSam Ravnborg tristate "/dev/cpu/*/cpuid - CPU information support" 1364a7f7f624SMasahiro Yamada help 1365506f1d07SSam Ravnborg This device gives processes access to the x86 CPUID instruction to 1366506f1d07SSam Ravnborg be executed on a specific processor. It is a character device 1367506f1d07SSam Ravnborg with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1368506f1d07SSam Ravnborg /dev/cpu/31/cpuid. 1369506f1d07SSam Ravnborg 1370506f1d07SSam Ravnborgchoice 1371506f1d07SSam Ravnborg prompt "High Memory Support" 13726fc108a0SJan Beulich default HIGHMEM4G 1373506f1d07SSam Ravnborg depends on X86_32 1374506f1d07SSam Ravnborg 1375506f1d07SSam Ravnborgconfig NOHIGHMEM 1376506f1d07SSam Ravnborg bool "off" 1377a7f7f624SMasahiro Yamada help 1378506f1d07SSam Ravnborg Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1379506f1d07SSam Ravnborg However, the address space of 32-bit x86 processors is only 4 1380506f1d07SSam Ravnborg Gigabytes large. That means that, if you have a large amount of 1381506f1d07SSam Ravnborg physical memory, not all of it can be "permanently mapped" by the 1382506f1d07SSam Ravnborg kernel. The physical memory that's not permanently mapped is called 1383506f1d07SSam Ravnborg "high memory". 1384506f1d07SSam Ravnborg 1385506f1d07SSam Ravnborg If you are compiling a kernel which will never run on a machine with 1386506f1d07SSam Ravnborg more than 1 Gigabyte total physical RAM, answer "off" here (default 1387506f1d07SSam Ravnborg choice and suitable for most users). This will result in a "3GB/1GB" 1388506f1d07SSam Ravnborg split: 3GB are mapped so that each process sees a 3GB virtual memory 1389506f1d07SSam Ravnborg space and the remaining part of the 4GB virtual memory space is used 1390506f1d07SSam Ravnborg by the kernel to permanently map as much physical memory as 1391506f1d07SSam Ravnborg possible. 1392506f1d07SSam Ravnborg 1393506f1d07SSam Ravnborg If the machine has between 1 and 4 Gigabytes physical RAM, then 1394506f1d07SSam Ravnborg answer "4GB" here. 1395506f1d07SSam Ravnborg 1396506f1d07SSam Ravnborg If more than 4 Gigabytes is used then answer "64GB" here. This 1397506f1d07SSam Ravnborg selection turns Intel PAE (Physical Address Extension) mode on. 1398506f1d07SSam Ravnborg PAE implements 3-level paging on IA32 processors. PAE is fully 1399506f1d07SSam Ravnborg supported by Linux, PAE mode is implemented on all recent Intel 1400506f1d07SSam Ravnborg processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1401506f1d07SSam Ravnborg then the kernel will not boot on CPUs that don't support PAE! 1402506f1d07SSam Ravnborg 1403506f1d07SSam Ravnborg The actual amount of total physical memory will either be 1404506f1d07SSam Ravnborg auto detected or can be forced by using a kernel command line option 1405506f1d07SSam Ravnborg such as "mem=256M". (Try "man bootparam" or see the documentation of 1406506f1d07SSam Ravnborg your boot loader (lilo or loadlin) about how to pass options to the 1407506f1d07SSam Ravnborg kernel at boot time.) 1408506f1d07SSam Ravnborg 1409506f1d07SSam Ravnborg If unsure, say "off". 1410506f1d07SSam Ravnborg 1411506f1d07SSam Ravnborgconfig HIGHMEM4G 1412506f1d07SSam Ravnborg bool "4GB" 1413a7f7f624SMasahiro Yamada help 1414506f1d07SSam Ravnborg Select this if you have a 32-bit processor and between 1 and 4 1415506f1d07SSam Ravnborg gigabytes of physical RAM. 1416506f1d07SSam Ravnborg 1417506f1d07SSam Ravnborgconfig HIGHMEM64G 1418506f1d07SSam Ravnborg bool "64GB" 141988a2b4edSArnd Bergmann depends on X86_HAVE_PAE 1420506f1d07SSam Ravnborg select X86_PAE 1421a7f7f624SMasahiro Yamada help 1422506f1d07SSam Ravnborg Select this if you have a 32-bit processor and more than 4 1423506f1d07SSam Ravnborg gigabytes of physical RAM. 1424506f1d07SSam Ravnborg 1425506f1d07SSam Ravnborgendchoice 1426506f1d07SSam Ravnborg 1427506f1d07SSam Ravnborgchoice 14286a108a14SDavid Rientjes prompt "Memory split" if EXPERT 1429506f1d07SSam Ravnborg default VMSPLIT_3G 1430506f1d07SSam Ravnborg depends on X86_32 1431a7f7f624SMasahiro Yamada help 1432506f1d07SSam Ravnborg Select the desired split between kernel and user memory. 1433506f1d07SSam Ravnborg 1434506f1d07SSam Ravnborg If the address range available to the kernel is less than the 1435506f1d07SSam Ravnborg physical memory installed, the remaining memory will be available 1436506f1d07SSam Ravnborg as "high memory". Accessing high memory is a little more costly 1437506f1d07SSam Ravnborg than low memory, as it needs to be mapped into the kernel first. 1438506f1d07SSam Ravnborg Note that increasing the kernel address space limits the range 1439506f1d07SSam Ravnborg available to user programs, making the address space there 1440506f1d07SSam Ravnborg tighter. Selecting anything other than the default 3G/1G split 1441506f1d07SSam Ravnborg will also likely make your kernel incompatible with binary-only 1442506f1d07SSam Ravnborg kernel modules. 1443506f1d07SSam Ravnborg 1444506f1d07SSam Ravnborg If you are not absolutely sure what you are doing, leave this 1445506f1d07SSam Ravnborg option alone! 1446506f1d07SSam Ravnborg 1447506f1d07SSam Ravnborg config VMSPLIT_3G 1448506f1d07SSam Ravnborg bool "3G/1G user/kernel split" 1449506f1d07SSam Ravnborg config VMSPLIT_3G_OPT 1450506f1d07SSam Ravnborg depends on !X86_PAE 1451506f1d07SSam Ravnborg bool "3G/1G user/kernel split (for full 1G low memory)" 1452506f1d07SSam Ravnborg config VMSPLIT_2G 1453506f1d07SSam Ravnborg bool "2G/2G user/kernel split" 1454506f1d07SSam Ravnborg config VMSPLIT_2G_OPT 1455506f1d07SSam Ravnborg depends on !X86_PAE 1456506f1d07SSam Ravnborg bool "2G/2G user/kernel split (for full 2G low memory)" 1457506f1d07SSam Ravnborg config VMSPLIT_1G 1458506f1d07SSam Ravnborg bool "1G/3G user/kernel split" 1459506f1d07SSam Ravnborgendchoice 1460506f1d07SSam Ravnborg 1461506f1d07SSam Ravnborgconfig PAGE_OFFSET 1462506f1d07SSam Ravnborg hex 1463506f1d07SSam Ravnborg default 0xB0000000 if VMSPLIT_3G_OPT 1464506f1d07SSam Ravnborg default 0x80000000 if VMSPLIT_2G 1465506f1d07SSam Ravnborg default 0x78000000 if VMSPLIT_2G_OPT 1466506f1d07SSam Ravnborg default 0x40000000 if VMSPLIT_1G 1467506f1d07SSam Ravnborg default 0xC0000000 1468506f1d07SSam Ravnborg depends on X86_32 1469506f1d07SSam Ravnborg 1470506f1d07SSam Ravnborgconfig HIGHMEM 14713c2362e6SHarvey Harrison def_bool y 1472506f1d07SSam Ravnborg depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1473506f1d07SSam Ravnborg 1474506f1d07SSam Ravnborgconfig X86_PAE 14759ba16087SJan Beulich bool "PAE (Physical Address Extension) Support" 147688a2b4edSArnd Bergmann depends on X86_32 && X86_HAVE_PAE 1477d4a451d5SChristoph Hellwig select PHYS_ADDR_T_64BIT 14789d99c712SChristian Melki select SWIOTLB 1479a7f7f624SMasahiro Yamada help 1480506f1d07SSam Ravnborg PAE is required for NX support, and furthermore enables 1481506f1d07SSam Ravnborg larger swapspace support for non-overcommit purposes. It 1482506f1d07SSam Ravnborg has the cost of more pagetable lookup overhead, and also 1483506f1d07SSam Ravnborg consumes more pagetable space per process. 1484506f1d07SSam Ravnborg 148577ef56e4SKirill A. Shutemovconfig X86_5LEVEL 148677ef56e4SKirill A. Shutemov bool "Enable 5-level page tables support" 148718ec1eafSKirill A. Shutemov default y 1488eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 1489162434e7SKirill A. Shutemov select SPARSEMEM_VMEMMAP 149077ef56e4SKirill A. Shutemov depends on X86_64 1491a7f7f624SMasahiro Yamada help 149277ef56e4SKirill A. Shutemov 5-level paging enables access to larger address space: 149377ef56e4SKirill A. Shutemov up to 128 PiB of virtual address space and 4 PiB of 149477ef56e4SKirill A. Shutemov physical address space. 149577ef56e4SKirill A. Shutemov 149677ef56e4SKirill A. Shutemov It will be supported by future Intel CPUs. 149777ef56e4SKirill A. Shutemov 14986657fca0SKirill A. Shutemov A kernel with the option enabled can be booted on machines that 14996657fca0SKirill A. Shutemov support 4- or 5-level paging. 150077ef56e4SKirill A. Shutemov 1501ff61f079SJonathan Corbet See Documentation/arch/x86/x86_64/5level-paging.rst for more 150277ef56e4SKirill A. Shutemov information. 150377ef56e4SKirill A. Shutemov 150477ef56e4SKirill A. Shutemov Say N if unsure. 150577ef56e4SKirill A. Shutemov 150610971ab2SIngo Molnarconfig X86_DIRECT_GBPAGES 1507e5008abeSLuis R. Rodriguez def_bool y 15082e1da13fSVlastimil Babka depends on X86_64 1509a7f7f624SMasahiro Yamada help 151010971ab2SIngo Molnar Certain kernel features effectively disable kernel 151110971ab2SIngo Molnar linear 1 GB mappings (even if the CPU otherwise 151210971ab2SIngo Molnar supports them), so don't confuse the user by printing 151310971ab2SIngo Molnar that we have them enabled. 15149e899816SNick Piggin 15155c280cf6SThomas Gleixnerconfig X86_CPA_STATISTICS 15165c280cf6SThomas Gleixner bool "Enable statistic for Change Page Attribute" 15175c280cf6SThomas Gleixner depends on DEBUG_FS 1518a7f7f624SMasahiro Yamada help 1519b75baaf3SIngo Molnar Expose statistics about the Change Page Attribute mechanism, which 1520a943245aSColin Ian King helps to determine the effectiveness of preserving large and huge 15215c280cf6SThomas Gleixner page mappings when mapping protections are changed. 15225c280cf6SThomas Gleixner 152320f07a04SKirill A. Shutemovconfig X86_MEM_ENCRYPT 152420f07a04SKirill A. Shutemov select ARCH_HAS_FORCE_DMA_UNENCRYPTED 152520f07a04SKirill A. Shutemov select DYNAMIC_PHYSICAL_MASK 152620f07a04SKirill A. Shutemov def_bool n 152720f07a04SKirill A. Shutemov 15287744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT 15297744ccdbSTom Lendacky bool "AMD Secure Memory Encryption (SME) support" 15307744ccdbSTom Lendacky depends on X86_64 && CPU_SUP_AMD 15316c321179STom Lendacky depends on EFI_STUB 153282fef0adSDavid Rientjes select DMA_COHERENT_POOL 1533ce9084baSArd Biesheuvel select ARCH_USE_MEMREMAP_PROT 1534597cfe48SJoerg Roedel select INSTRUCTION_DECODER 1535aa5a4611STom Lendacky select ARCH_HAS_CC_PLATFORM 153620f07a04SKirill A. Shutemov select X86_MEM_ENCRYPT 15376c321179STom Lendacky select UNACCEPTED_MEMORY 1538a7f7f624SMasahiro Yamada help 15397744ccdbSTom Lendacky Say yes to enable support for the encryption of system memory. 15407744ccdbSTom Lendacky This requires an AMD processor that supports Secure Memory 15417744ccdbSTom Lendacky Encryption (SME). 15427744ccdbSTom Lendacky 15437744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 15447744ccdbSTom Lendacky bool "Activate AMD Secure Memory Encryption (SME) by default" 15457744ccdbSTom Lendacky depends on AMD_MEM_ENCRYPT 1546a7f7f624SMasahiro Yamada help 15477744ccdbSTom Lendacky Say yes to have system memory encrypted by default if running on 15487744ccdbSTom Lendacky an AMD processor that supports Secure Memory Encryption (SME). 15497744ccdbSTom Lendacky 15507744ccdbSTom Lendacky If set to Y, then the encryption of system memory can be 15517744ccdbSTom Lendacky deactivated with the mem_encrypt=off command line option. 15527744ccdbSTom Lendacky 15537744ccdbSTom Lendacky If set to N, then the encryption of system memory can be 15547744ccdbSTom Lendacky activated with the mem_encrypt=on command line option. 15557744ccdbSTom Lendacky 1556506f1d07SSam Ravnborg# Common NUMA Features 1557506f1d07SSam Ravnborgconfig NUMA 1558e133f6eaSRandy Dunlap bool "NUMA Memory Allocation and Scheduler Support" 1559506f1d07SSam Ravnborg depends on SMP 1560b5660ba7SH. Peter Anvin depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1561b5660ba7SH. Peter Anvin default y if X86_BIGSMP 15627ecd19cfSKefeng Wang select USE_PERCPU_NUMA_NODE_ID 15630c436a58SSaurabh Sengar select OF_NUMA if OF 1564a7f7f624SMasahiro Yamada help 1565e133f6eaSRandy Dunlap Enable NUMA (Non-Uniform Memory Access) support. 1566fd51b2d7SKOSAKI Motohiro 1567506f1d07SSam Ravnborg The kernel will try to allocate memory used by a CPU on the 1568506f1d07SSam Ravnborg local memory controller of the CPU and add some more 1569506f1d07SSam Ravnborg NUMA awareness to the kernel. 1570506f1d07SSam Ravnborg 1571c280ea5eSIngo Molnar For 64-bit this is recommended if the system is Intel Core i7 1572fd51b2d7SKOSAKI Motohiro (or later), AMD Opteron, or EM64T NUMA. 1573fd51b2d7SKOSAKI Motohiro 1574b5660ba7SH. Peter Anvin For 32-bit this is only needed if you boot a 32-bit 15757cf6c945SDavid Rientjes kernel on a 64-bit NUMA platform. 1576fd51b2d7SKOSAKI Motohiro 1577fd51b2d7SKOSAKI Motohiro Otherwise, you should say N. 1578506f1d07SSam Ravnborg 1579eec1d4faSHans Rosenfeldconfig AMD_NUMA 15803c2362e6SHarvey Harrison def_bool y 15813c2362e6SHarvey Harrison prompt "Old style AMD Opteron NUMA detection" 15825da0ef9aSTejun Heo depends on X86_64 && NUMA && PCI 1583a7f7f624SMasahiro Yamada help 1584eec1d4faSHans Rosenfeld Enable AMD NUMA node topology detection. You should say Y here if 1585eec1d4faSHans Rosenfeld you have a multi processor AMD system. This uses an old method to 1586eec1d4faSHans Rosenfeld read the NUMA configuration directly from the builtin Northbridge 1587eec1d4faSHans Rosenfeld of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1588eec1d4faSHans Rosenfeld which also takes priority if both are compiled in. 1589506f1d07SSam Ravnborg 1590506f1d07SSam Ravnborgconfig X86_64_ACPI_NUMA 15913c2362e6SHarvey Harrison def_bool y 15923c2362e6SHarvey Harrison prompt "ACPI NUMA detection" 1593506f1d07SSam Ravnborg depends on X86_64 && NUMA && ACPI && PCI 1594506f1d07SSam Ravnborg select ACPI_NUMA 1595a7f7f624SMasahiro Yamada help 1596506f1d07SSam Ravnborg Enable ACPI SRAT based node topology detection. 1597506f1d07SSam Ravnborg 1598506f1d07SSam Ravnborgconfig NUMA_EMU 1599506f1d07SSam Ravnborg bool "NUMA emulation" 16001b7e03efSTejun Heo depends on NUMA 1601a7f7f624SMasahiro Yamada help 1602506f1d07SSam Ravnborg Enable NUMA emulation. A flat machine will be split 1603506f1d07SSam Ravnborg into virtual nodes when booted with "numa=fake=N", where N is the 1604506f1d07SSam Ravnborg number of nodes. This is only useful for debugging. 1605506f1d07SSam Ravnborg 1606506f1d07SSam Ravnborgconfig NODES_SHIFT 1607d25e26b6SLinus Torvalds int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 160851591e31SDavid Rientjes range 1 10 160951591e31SDavid Rientjes default "10" if MAXSMP 1610506f1d07SSam Ravnborg default "6" if X86_64 1611506f1d07SSam Ravnborg default "3" 1612a9ee6cf5SMike Rapoport depends on NUMA 1613a7f7f624SMasahiro Yamada help 16141184dc2fSMike Travis Specify the maximum number of NUMA Nodes available on the target 1615692105b8SMatt LaPlante system. Increases memory reserved to accommodate various tables. 1616506f1d07SSam Ravnborg 1617506f1d07SSam Ravnborgconfig ARCH_FLATMEM_ENABLE 1618506f1d07SSam Ravnborg def_bool y 16193b16651fSTejun Heo depends on X86_32 && !NUMA 1620506f1d07SSam Ravnborg 1621506f1d07SSam Ravnborgconfig ARCH_SPARSEMEM_ENABLE 1622506f1d07SSam Ravnborg def_bool y 16236ea30386SKees Cook depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1624506f1d07SSam Ravnborg select SPARSEMEM_STATIC if X86_32 1625506f1d07SSam Ravnborg select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1626506f1d07SSam Ravnborg 16273b16651fSTejun Heoconfig ARCH_SPARSEMEM_DEFAULT 16286ad57f7fSMike Rapoport def_bool X86_64 || (NUMA && X86_32) 16293b16651fSTejun Heo 1630506f1d07SSam Ravnborgconfig ARCH_SELECT_MEMORY_MODEL 1631506f1d07SSam Ravnborg def_bool y 16324eda2bc3SDavid Hildenbrand depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE 1633506f1d07SSam Ravnborg 1634506f1d07SSam Ravnborgconfig ARCH_MEMORY_PROBE 1635a0842b70SToshi Kani bool "Enable sysfs memory/probe interface" 16365c11f00bSDavid Hildenbrand depends on MEMORY_HOTPLUG 1637a0842b70SToshi Kani help 1638a0842b70SToshi Kani This option enables a sysfs memory/probe interface for testing. 1639cb1aaebeSMauro Carvalho Chehab See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1640a0842b70SToshi Kani If you are unsure how to answer this question, answer N. 1641506f1d07SSam Ravnborg 16423b16651fSTejun Heoconfig ARCH_PROC_KCORE_TEXT 16433b16651fSTejun Heo def_bool y 16443b16651fSTejun Heo depends on X86_64 && PROC_KCORE 16453b16651fSTejun Heo 1646a29815a3SAvi Kivityconfig ILLEGAL_POINTER_VALUE 1647a29815a3SAvi Kivity hex 1648a29815a3SAvi Kivity default 0 if X86_32 1649a29815a3SAvi Kivity default 0xdead000000000000 if X86_64 1650a29815a3SAvi Kivity 16517a67832cSDan Williamsconfig X86_PMEM_LEGACY_DEVICE 16527a67832cSDan Williams bool 16537a67832cSDan Williams 1654ec776ef6SChristoph Hellwigconfig X86_PMEM_LEGACY 16557a67832cSDan Williams tristate "Support non-standard NVDIMMs and ADR protected memory" 16569f53f9faSDan Williams depends on PHYS_ADDR_T_64BIT 16579f53f9faSDan Williams depends on BLK_DEV 16587a67832cSDan Williams select X86_PMEM_LEGACY_DEVICE 16597b27a862SDan Williams select NUMA_KEEP_MEMINFO if NUMA 16609f53f9faSDan Williams select LIBNVDIMM 1661ec776ef6SChristoph Hellwig help 1662ec776ef6SChristoph Hellwig Treat memory marked using the non-standard e820 type of 12 as used 1663ec776ef6SChristoph Hellwig by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1664ec776ef6SChristoph Hellwig The kernel will offer these regions to the 'pmem' driver so 1665ec776ef6SChristoph Hellwig they can be used for persistent storage. 1666ec776ef6SChristoph Hellwig 1667ec776ef6SChristoph Hellwig Say Y if unsure. 1668ec776ef6SChristoph Hellwig 1669506f1d07SSam Ravnborgconfig HIGHPTE 1670506f1d07SSam Ravnborg bool "Allocate 3rd-level pagetables from highmem" 16716fc108a0SJan Beulich depends on HIGHMEM 1672a7f7f624SMasahiro Yamada help 1673506f1d07SSam Ravnborg The VM uses one page table entry for each page of physical memory. 1674506f1d07SSam Ravnborg For systems with a lot of RAM, this can be wasteful of precious 1675506f1d07SSam Ravnborg low memory. Setting this option will put user-space page table 1676506f1d07SSam Ravnborg entries in high memory. 1677506f1d07SSam Ravnborg 16789f077871SJeremy Fitzhardingeconfig X86_CHECK_BIOS_CORRUPTION 16799f077871SJeremy Fitzhardinge bool "Check for low memory corruption" 1680a7f7f624SMasahiro Yamada help 16819f077871SJeremy Fitzhardinge Periodically check for memory corruption in low memory, which 16829f077871SJeremy Fitzhardinge is suspected to be caused by BIOS. Even when enabled in the 16839f077871SJeremy Fitzhardinge configuration, it is disabled at runtime. Enable it by 16849f077871SJeremy Fitzhardinge setting "memory_corruption_check=1" on the kernel command 16859f077871SJeremy Fitzhardinge line. By default it scans the low 64k of memory every 60 16869f077871SJeremy Fitzhardinge seconds; see the memory_corruption_check_size and 16879f077871SJeremy Fitzhardinge memory_corruption_check_period parameters in 16888c27ceffSMauro Carvalho Chehab Documentation/admin-guide/kernel-parameters.rst to adjust this. 16899f077871SJeremy Fitzhardinge 16909f077871SJeremy Fitzhardinge When enabled with the default parameters, this option has 16919f077871SJeremy Fitzhardinge almost no overhead, as it reserves a relatively small amount 16929f077871SJeremy Fitzhardinge of memory and scans it infrequently. It both detects corruption 16939f077871SJeremy Fitzhardinge and prevents it from affecting the running system. 16949f077871SJeremy Fitzhardinge 16959f077871SJeremy Fitzhardinge It is, however, intended as a diagnostic tool; if repeatable 16969f077871SJeremy Fitzhardinge BIOS-originated corruption always affects the same memory, 16979f077871SJeremy Fitzhardinge you can use memmap= to prevent the kernel from using that 16989f077871SJeremy Fitzhardinge memory. 16999f077871SJeremy Fitzhardinge 1700c885df50SJeremy Fitzhardingeconfig X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1701c885df50SJeremy Fitzhardinge bool "Set the default setting of memory_corruption_check" 1702c885df50SJeremy Fitzhardinge depends on X86_CHECK_BIOS_CORRUPTION 1703c885df50SJeremy Fitzhardinge default y 1704a7f7f624SMasahiro Yamada help 1705c885df50SJeremy Fitzhardinge Set whether the default state of memory_corruption_check is 1706c885df50SJeremy Fitzhardinge on or off. 1707c885df50SJeremy Fitzhardinge 1708506f1d07SSam Ravnborgconfig MATH_EMULATION 1709506f1d07SSam Ravnborg bool 1710a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 171187d6021bSArnd Bergmann prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1712a7f7f624SMasahiro Yamada help 1713506f1d07SSam Ravnborg Linux can emulate a math coprocessor (used for floating point 1714506f1d07SSam Ravnborg operations) if you don't have one. 486DX and Pentium processors have 1715506f1d07SSam Ravnborg a math coprocessor built in, 486SX and 386 do not, unless you added 1716506f1d07SSam Ravnborg a 487DX or 387, respectively. (The messages during boot time can 1717506f1d07SSam Ravnborg give you some hints here ["man dmesg"].) Everyone needs either a 1718506f1d07SSam Ravnborg coprocessor or this emulation. 1719506f1d07SSam Ravnborg 1720506f1d07SSam Ravnborg If you don't have a math coprocessor, you need to say Y here; if you 1721506f1d07SSam Ravnborg say Y here even though you have a coprocessor, the coprocessor will 1722506f1d07SSam Ravnborg be used nevertheless. (This behavior can be changed with the kernel 1723506f1d07SSam Ravnborg command line option "no387", which comes handy if your coprocessor 1724506f1d07SSam Ravnborg is broken. Try "man bootparam" or see the documentation of your boot 1725506f1d07SSam Ravnborg loader (lilo or loadlin) about how to pass options to the kernel at 1726506f1d07SSam Ravnborg boot time.) This means that it is a good idea to say Y here if you 1727506f1d07SSam Ravnborg intend to use this kernel on different machines. 1728506f1d07SSam Ravnborg 1729506f1d07SSam Ravnborg More information about the internals of the Linux math coprocessor 1730506f1d07SSam Ravnborg emulation can be found in <file:arch/x86/math-emu/README>. 1731506f1d07SSam Ravnborg 1732506f1d07SSam Ravnborg If you are not sure, say Y; apart from resulting in a 66 KB bigger 1733506f1d07SSam Ravnborg kernel, it won't hurt. 1734506f1d07SSam Ravnborg 1735506f1d07SSam Ravnborgconfig MTRR 17366fc108a0SJan Beulich def_bool y 17376a108a14SDavid Rientjes prompt "MTRR (Memory Type Range Register) support" if EXPERT 1738a7f7f624SMasahiro Yamada help 1739506f1d07SSam Ravnborg On Intel P6 family processors (Pentium Pro, Pentium II and later) 1740506f1d07SSam Ravnborg the Memory Type Range Registers (MTRRs) may be used to control 1741506f1d07SSam Ravnborg processor access to memory ranges. This is most useful if you have 1742506f1d07SSam Ravnborg a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1743506f1d07SSam Ravnborg allows bus write transfers to be combined into a larger transfer 1744506f1d07SSam Ravnborg before bursting over the PCI/AGP bus. This can increase performance 1745506f1d07SSam Ravnborg of image write operations 2.5 times or more. Saying Y here creates a 1746506f1d07SSam Ravnborg /proc/mtrr file which may be used to manipulate your processor's 1747506f1d07SSam Ravnborg MTRRs. Typically the X server should use this. 1748506f1d07SSam Ravnborg 1749506f1d07SSam Ravnborg This code has a reasonably generic interface so that similar 1750506f1d07SSam Ravnborg control registers on other processors can be easily supported 1751506f1d07SSam Ravnborg as well: 1752506f1d07SSam Ravnborg 1753506f1d07SSam Ravnborg The Cyrix 6x86, 6x86MX and M II processors have Address Range 1754506f1d07SSam Ravnborg Registers (ARRs) which provide a similar functionality to MTRRs. For 1755506f1d07SSam Ravnborg these, the ARRs are used to emulate the MTRRs. 1756506f1d07SSam Ravnborg The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1757506f1d07SSam Ravnborg MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1758506f1d07SSam Ravnborg write-combining. All of these processors are supported by this code 1759506f1d07SSam Ravnborg and it makes sense to say Y here if you have one of them. 1760506f1d07SSam Ravnborg 1761506f1d07SSam Ravnborg Saying Y here also fixes a problem with buggy SMP BIOSes which only 1762506f1d07SSam Ravnborg set the MTRRs for the boot CPU and not for the secondary CPUs. This 1763506f1d07SSam Ravnborg can lead to all sorts of problems, so it's good to say Y here. 1764506f1d07SSam Ravnborg 1765506f1d07SSam Ravnborg You can safely say Y even if your machine doesn't have MTRRs, you'll 1766506f1d07SSam Ravnborg just add about 9 KB to your kernel. 1767506f1d07SSam Ravnborg 1768ff61f079SJonathan Corbet See <file:Documentation/arch/x86/mtrr.rst> for more information. 1769506f1d07SSam Ravnborg 177095ffa243SYinghai Luconfig MTRR_SANITIZER 17712ffb3501SYinghai Lu def_bool y 177295ffa243SYinghai Lu prompt "MTRR cleanup support" 177395ffa243SYinghai Lu depends on MTRR 1774a7f7f624SMasahiro Yamada help 1775aba3728cSThomas Gleixner Convert MTRR layout from continuous to discrete, so X drivers can 1776aba3728cSThomas Gleixner add writeback entries. 177795ffa243SYinghai Lu 1778aba3728cSThomas Gleixner Can be disabled with disable_mtrr_cleanup on the kernel command line. 1779692105b8SMatt LaPlante The largest mtrr entry size for a continuous block can be set with 1780aba3728cSThomas Gleixner mtrr_chunk_size. 178195ffa243SYinghai Lu 17822ffb3501SYinghai Lu If unsure, say Y. 178395ffa243SYinghai Lu 178495ffa243SYinghai Luconfig MTRR_SANITIZER_ENABLE_DEFAULT 1785f5098d62SYinghai Lu int "MTRR cleanup enable value (0-1)" 1786f5098d62SYinghai Lu range 0 1 1787f5098d62SYinghai Lu default "0" 178895ffa243SYinghai Lu depends on MTRR_SANITIZER 1789a7f7f624SMasahiro Yamada help 1790f5098d62SYinghai Lu Enable mtrr cleanup default value 179195ffa243SYinghai Lu 179212031a62SYinghai Luconfig MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 179312031a62SYinghai Lu int "MTRR cleanup spare reg num (0-7)" 179412031a62SYinghai Lu range 0 7 179512031a62SYinghai Lu default "1" 179612031a62SYinghai Lu depends on MTRR_SANITIZER 1797a7f7f624SMasahiro Yamada help 179812031a62SYinghai Lu mtrr cleanup spare entries default, it can be changed via 1799aba3728cSThomas Gleixner mtrr_spare_reg_nr=N on the kernel command line. 180012031a62SYinghai Lu 18012e5d9c85Svenkatesh.pallipadi@intel.comconfig X86_PAT 18026fc108a0SJan Beulich def_bool y 18036a108a14SDavid Rientjes prompt "x86 PAT support" if EXPERT 18042a8a2719SIngo Molnar depends on MTRR 1805a7f7f624SMasahiro Yamada help 18062e5d9c85Svenkatesh.pallipadi@intel.com Use PAT attributes to setup page level cache control. 1807042b78e4SVenki Pallipadi 18082e5d9c85Svenkatesh.pallipadi@intel.com PATs are the modern equivalents of MTRRs and are much more 18092e5d9c85Svenkatesh.pallipadi@intel.com flexible than MTRRs. 18102e5d9c85Svenkatesh.pallipadi@intel.com 18112e5d9c85Svenkatesh.pallipadi@intel.com Say N here if you see bootup problems (boot crash, boot hang, 1812042b78e4SVenki Pallipadi spontaneous reboots) or a non-working video driver. 18132e5d9c85Svenkatesh.pallipadi@intel.com 18142e5d9c85Svenkatesh.pallipadi@intel.com If unsure, say Y. 18152e5d9c85Svenkatesh.pallipadi@intel.com 181646cf98cdSVenkatesh Pallipadiconfig ARCH_USES_PG_UNCACHED 181746cf98cdSVenkatesh Pallipadi def_bool y 181846cf98cdSVenkatesh Pallipadi depends on X86_PAT 181946cf98cdSVenkatesh Pallipadi 1820b971880fSBabu Mogerconfig X86_UMIP 1821796ebc81SRicardo Neri def_bool y 1822b971880fSBabu Moger prompt "User Mode Instruction Prevention" if EXPERT 1823a7f7f624SMasahiro Yamada help 1824b971880fSBabu Moger User Mode Instruction Prevention (UMIP) is a security feature in 1825b971880fSBabu Moger some x86 processors. If enabled, a general protection fault is 1826b971880fSBabu Moger issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1827b971880fSBabu Moger executed in user mode. These instructions unnecessarily expose 1828b971880fSBabu Moger information about the hardware state. 1829796ebc81SRicardo Neri 1830796ebc81SRicardo Neri The vast majority of applications do not use these instructions. 1831796ebc81SRicardo Neri For the very few that do, software emulation is provided in 1832796ebc81SRicardo Neri specific cases in protected and virtual-8086 modes. Emulated 1833796ebc81SRicardo Neri results are dummy. 1834aa35f896SRicardo Neri 1835156ff4a5SPeter Zijlstraconfig CC_HAS_IBT 1836156ff4a5SPeter Zijlstra # GCC >= 9 and binutils >= 2.29 1837156ff4a5SPeter Zijlstra # Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654 1838156ff4a5SPeter Zijlstra # Clang/LLVM >= 14 1839262448f3SNathan Chancellor # https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f 1840262448f3SNathan Chancellor # https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332 1841156ff4a5SPeter Zijlstra def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \ 1842262448f3SNathan Chancellor (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \ 1843156ff4a5SPeter Zijlstra $(as-instr,endbr64) 1844156ff4a5SPeter Zijlstra 184518e66b69SRick Edgecombeconfig X86_CET 184618e66b69SRick Edgecombe def_bool n 184718e66b69SRick Edgecombe help 184818e66b69SRick Edgecombe CET features configured (Shadow stack or IBT) 184918e66b69SRick Edgecombe 1850156ff4a5SPeter Zijlstraconfig X86_KERNEL_IBT 1851156ff4a5SPeter Zijlstra prompt "Indirect Branch Tracking" 18524fd5f70cSKees Cook def_bool y 185303f16cd0SJosh Poimboeuf depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL 1854f6a2c2b2SNathan Chancellor # https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f 1855f6a2c2b2SNathan Chancellor depends on !LD_IS_LLD || LLD_VERSION >= 140000 185603f16cd0SJosh Poimboeuf select OBJTOOL 185718e66b69SRick Edgecombe select X86_CET 1858156ff4a5SPeter Zijlstra help 1859156ff4a5SPeter Zijlstra Build the kernel with support for Indirect Branch Tracking, a 1860156ff4a5SPeter Zijlstra hardware support course-grain forward-edge Control Flow Integrity 1861156ff4a5SPeter Zijlstra protection. It enforces that all indirect calls must land on 1862156ff4a5SPeter Zijlstra an ENDBR instruction, as such, the compiler will instrument the 1863156ff4a5SPeter Zijlstra code with them to make this happen. 1864156ff4a5SPeter Zijlstra 1865ed53a0d9SPeter Zijlstra In addition to building the kernel with IBT, seal all functions that 18664cdfc11bSNur Hussein are not indirect call targets, avoiding them ever becoming one. 1867ed53a0d9SPeter Zijlstra 1868ed53a0d9SPeter Zijlstra This requires LTO like objtool runs and will slow down the build. It 1869ed53a0d9SPeter Zijlstra does significantly reduce the number of ENDBR instructions in the 1870ed53a0d9SPeter Zijlstra kernel image. 1871ed53a0d9SPeter Zijlstra 187235e97790SDave Hansenconfig X86_INTEL_MEMORY_PROTECTION_KEYS 187338f3e775SBabu Moger prompt "Memory Protection Keys" 187435e97790SDave Hansen def_bool y 1875284244a9SDave Hansen # Note: only available in 64-bit mode 187638f3e775SBabu Moger depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 187752c8e601SIngo Molnar select ARCH_USES_HIGH_VMA_FLAGS 187852c8e601SIngo Molnar select ARCH_HAS_PKEYS 1879a7f7f624SMasahiro Yamada help 1880284244a9SDave Hansen Memory Protection Keys provides a mechanism for enforcing 1881284244a9SDave Hansen page-based protections, but without requiring modification of the 1882284244a9SDave Hansen page tables when an application changes protection domains. 1883284244a9SDave Hansen 18841eecbcdcSMauro Carvalho Chehab For details, see Documentation/core-api/protection-keys.rst 1885284244a9SDave Hansen 1886284244a9SDave Hansen If unsure, say y. 188735e97790SDave Hansen 1888db616173SMichal Hockochoice 1889db616173SMichal Hocko prompt "TSX enable mode" 1890db616173SMichal Hocko depends on CPU_SUP_INTEL 1891db616173SMichal Hocko default X86_INTEL_TSX_MODE_OFF 1892db616173SMichal Hocko help 1893db616173SMichal Hocko Intel's TSX (Transactional Synchronization Extensions) feature 1894db616173SMichal Hocko allows to optimize locking protocols through lock elision which 1895db616173SMichal Hocko can lead to a noticeable performance boost. 1896db616173SMichal Hocko 1897db616173SMichal Hocko On the other hand it has been shown that TSX can be exploited 1898db616173SMichal Hocko to form side channel attacks (e.g. TAA) and chances are there 1899db616173SMichal Hocko will be more of those attacks discovered in the future. 1900db616173SMichal Hocko 1901db616173SMichal Hocko Therefore TSX is not enabled by default (aka tsx=off). An admin 1902db616173SMichal Hocko might override this decision by tsx=on the command line parameter. 1903db616173SMichal Hocko Even with TSX enabled, the kernel will attempt to enable the best 1904db616173SMichal Hocko possible TAA mitigation setting depending on the microcode available 1905db616173SMichal Hocko for the particular machine. 1906db616173SMichal Hocko 1907db616173SMichal Hocko This option allows to set the default tsx mode between tsx=on, =off 1908db616173SMichal Hocko and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1909db616173SMichal Hocko details. 1910db616173SMichal Hocko 1911db616173SMichal Hocko Say off if not sure, auto if TSX is in use but it should be used on safe 1912db616173SMichal Hocko platforms or on if TSX is in use and the security aspect of tsx is not 1913db616173SMichal Hocko relevant. 1914db616173SMichal Hocko 1915db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_OFF 1916db616173SMichal Hocko bool "off" 1917db616173SMichal Hocko help 1918db616173SMichal Hocko TSX is disabled if possible - equals to tsx=off command line parameter. 1919db616173SMichal Hocko 1920db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_ON 1921db616173SMichal Hocko bool "on" 1922db616173SMichal Hocko help 1923db616173SMichal Hocko TSX is always enabled on TSX capable HW - equals the tsx=on command 1924db616173SMichal Hocko line parameter. 1925db616173SMichal Hocko 1926db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_AUTO 1927db616173SMichal Hocko bool "auto" 1928db616173SMichal Hocko help 1929db616173SMichal Hocko TSX is enabled on TSX capable HW that is believed to be safe against 1930db616173SMichal Hocko side channel attacks- equals the tsx=auto command line parameter. 1931db616173SMichal Hockoendchoice 1932db616173SMichal Hocko 1933e7e05452SSean Christophersonconfig X86_SGX 1934e7e05452SSean Christopherson bool "Software Guard eXtensions (SGX)" 1935b8d1d163SDaniel Sneddon depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC 1936e7e05452SSean Christopherson depends on CRYPTO=y 1937e7e05452SSean Christopherson depends on CRYPTO_SHA256=y 1938e7e05452SSean Christopherson select MMU_NOTIFIER 1939901ddbb9SJarkko Sakkinen select NUMA_KEEP_MEMINFO if NUMA 194040e0e784STony Luck select XARRAY_MULTI 1941e7e05452SSean Christopherson help 1942e7e05452SSean Christopherson Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1943e7e05452SSean Christopherson that can be used by applications to set aside private regions of code 1944e7e05452SSean Christopherson and data, referred to as enclaves. An enclave's private memory can 1945e7e05452SSean Christopherson only be accessed by code running within the enclave. Accesses from 1946e7e05452SSean Christopherson outside the enclave, including other enclaves, are disallowed by 1947e7e05452SSean Christopherson hardware. 1948e7e05452SSean Christopherson 1949e7e05452SSean Christopherson If unsure, say N. 1950e7e05452SSean Christopherson 195118e66b69SRick Edgecombeconfig X86_USER_SHADOW_STACK 195218e66b69SRick Edgecombe bool "X86 userspace shadow stack" 195318e66b69SRick Edgecombe depends on AS_WRUSS 195418e66b69SRick Edgecombe depends on X86_64 195518e66b69SRick Edgecombe select ARCH_USES_HIGH_VMA_FLAGS 195618e66b69SRick Edgecombe select X86_CET 195718e66b69SRick Edgecombe help 195818e66b69SRick Edgecombe Shadow stack protection is a hardware feature that detects function 195918e66b69SRick Edgecombe return address corruption. This helps mitigate ROP attacks. 196018e66b69SRick Edgecombe Applications must be enabled to use it, and old userspace does not 196118e66b69SRick Edgecombe get protection "for free". 196218e66b69SRick Edgecombe 196318e66b69SRick Edgecombe CPUs supporting shadow stacks were first released in 2020. 196418e66b69SRick Edgecombe 196554acee60SDave Hansen See Documentation/arch/x86/shstk.rst for more information. 196618e66b69SRick Edgecombe 196718e66b69SRick Edgecombe If unsure, say N. 196818e66b69SRick Edgecombe 1969c33621b4SKai Huangconfig INTEL_TDX_HOST 1970c33621b4SKai Huang bool "Intel Trust Domain Extensions (TDX) host support" 1971c33621b4SKai Huang depends on CPU_SUP_INTEL 1972c33621b4SKai Huang depends on X86_64 1973c33621b4SKai Huang depends on KVM_INTEL 19743115cabdSKai Huang depends on X86_X2APIC 1975abe8dbabSKai Huang select ARCH_KEEP_MEMBLOCK 1976ac3a2208SKai Huang depends on CONTIG_ALLOC 1977cb8eb06dSDave Hansen depends on !KEXEC_CORE 197883e1bdc9SKai Huang depends on X86_MCE 1979c33621b4SKai Huang help 1980c33621b4SKai Huang Intel Trust Domain Extensions (TDX) protects guest VMs from malicious 1981c33621b4SKai Huang host and certain physical attacks. This option enables necessary TDX 1982c33621b4SKai Huang support in the host kernel to run confidential VMs. 1983c33621b4SKai Huang 1984c33621b4SKai Huang If unsure, say N. 1985c33621b4SKai Huang 1986506f1d07SSam Ravnborgconfig EFI 19879ba16087SJan Beulich bool "EFI runtime service support" 19885b83683fSHuang, Ying depends on ACPI 1989f6ce5002SSergey Vlasov select UCS2_STRING 1990022ee6c5SArd Biesheuvel select EFI_RUNTIME_WRAPPERS 19911ff2fc02STom Lendacky select ARCH_USE_MEMREMAP_PROT 1992aba7e066SArd Biesheuvel select EFI_RUNTIME_MAP if KEXEC_CORE 1993a7f7f624SMasahiro Yamada help 19948b2cb7a8SHuang, Ying This enables the kernel to use EFI runtime services that are 1995506f1d07SSam Ravnborg available (such as the EFI variable services). 1996506f1d07SSam Ravnborg 19978b2cb7a8SHuang, Ying This option is only useful on systems that have EFI firmware. 19988b2cb7a8SHuang, Ying In addition, you should use the latest ELILO loader available 19998b2cb7a8SHuang, Ying at <http://elilo.sourceforge.net> in order to take advantage 20008b2cb7a8SHuang, Ying of EFI runtime services. However, even with this option, the 20018b2cb7a8SHuang, Ying resultant kernel should continue to boot on existing non-EFI 20028b2cb7a8SHuang, Ying platforms. 2003506f1d07SSam Ravnborg 2004291f3632SMatt Flemingconfig EFI_STUB 2005291f3632SMatt Fleming bool "EFI stub support" 2006c6dbd3e5SPeter Zijlstra depends on EFI 20077b2a583aSMatt Fleming select RELOCATABLE 2008a7f7f624SMasahiro Yamada help 2009291f3632SMatt Fleming This kernel feature allows a bzImage to be loaded directly 2010291f3632SMatt Fleming by EFI firmware without the use of a bootloader. 2011291f3632SMatt Fleming 20124f4cfa6cSMauro Carvalho Chehab See Documentation/admin-guide/efi-stub.rst for more information. 20130c759662SMatt Fleming 2014cc3fdda2SArd Biesheuvelconfig EFI_HANDOVER_PROTOCOL 2015cc3fdda2SArd Biesheuvel bool "EFI handover protocol (DEPRECATED)" 2016cc3fdda2SArd Biesheuvel depends on EFI_STUB 2017cc3fdda2SArd Biesheuvel default y 2018cc3fdda2SArd Biesheuvel help 2019cc3fdda2SArd Biesheuvel Select this in order to include support for the deprecated EFI 2020cc3fdda2SArd Biesheuvel handover protocol, which defines alternative entry points into the 2021cc3fdda2SArd Biesheuvel EFI stub. This is a practice that has no basis in the UEFI 2022cc3fdda2SArd Biesheuvel specification, and requires a priori knowledge on the part of the 2023cc3fdda2SArd Biesheuvel bootloader about Linux/x86 specific ways of passing the command line 2024cc3fdda2SArd Biesheuvel and initrd, and where in memory those assets may be loaded. 2025cc3fdda2SArd Biesheuvel 2026cc3fdda2SArd Biesheuvel If in doubt, say Y. Even though the corresponding support is not 2027cc3fdda2SArd Biesheuvel present in upstream GRUB or other bootloaders, most distros build 2028cc3fdda2SArd Biesheuvel GRUB with numerous downstream patches applied, and may rely on the 2029cc3fdda2SArd Biesheuvel handover protocol as as result. 2030cc3fdda2SArd Biesheuvel 20317d453eeeSMatt Flemingconfig EFI_MIXED 20327d453eeeSMatt Fleming bool "EFI mixed-mode support" 20337d453eeeSMatt Fleming depends on EFI_STUB && X86_64 2034a7f7f624SMasahiro Yamada help 20357d453eeeSMatt Fleming Enabling this feature allows a 64-bit kernel to be booted 20367d453eeeSMatt Fleming on a 32-bit firmware, provided that your CPU supports 64-bit 20377d453eeeSMatt Fleming mode. 20387d453eeeSMatt Fleming 20397d453eeeSMatt Fleming Note that it is not possible to boot a mixed-mode enabled 20407d453eeeSMatt Fleming kernel via the EFI boot stub - a bootloader that supports 20417d453eeeSMatt Fleming the EFI handover protocol must be used. 20427d453eeeSMatt Fleming 20437d453eeeSMatt Fleming If unsure, say N. 20447d453eeeSMatt Fleming 20454059ba65SArd Biesheuvelconfig EFI_FAKE_MEMMAP 20464059ba65SArd Biesheuvel bool "Enable EFI fake memory map" 20474059ba65SArd Biesheuvel depends on EFI 20484059ba65SArd Biesheuvel help 20494059ba65SArd Biesheuvel Saying Y here will enable "efi_fake_mem" boot option. By specifying 20504059ba65SArd Biesheuvel this parameter, you can add arbitrary attribute to specific memory 20514059ba65SArd Biesheuvel range by updating original (firmware provided) EFI memmap. This is 20524059ba65SArd Biesheuvel useful for debugging of EFI memmap related feature, e.g., Address 20534059ba65SArd Biesheuvel Range Mirroring feature. 20544059ba65SArd Biesheuvel 20554059ba65SArd Biesheuvelconfig EFI_MAX_FAKE_MEM 20564059ba65SArd Biesheuvel int "maximum allowable number of ranges in efi_fake_mem boot option" 20574059ba65SArd Biesheuvel depends on EFI_FAKE_MEMMAP 20584059ba65SArd Biesheuvel range 1 128 20594059ba65SArd Biesheuvel default 8 20604059ba65SArd Biesheuvel help 20614059ba65SArd Biesheuvel Maximum allowable number of ranges in efi_fake_mem boot option. 20624059ba65SArd Biesheuvel Ranges can be set up to this value using comma-separated list. 20634059ba65SArd Biesheuvel The default value is 8. 20644059ba65SArd Biesheuvel 20651fff234dSArd Biesheuvelconfig EFI_RUNTIME_MAP 20661fff234dSArd Biesheuvel bool "Export EFI runtime maps to sysfs" if EXPERT 20671fff234dSArd Biesheuvel depends on EFI 20681fff234dSArd Biesheuvel help 20691fff234dSArd Biesheuvel Export EFI runtime memory regions to /sys/firmware/efi/runtime-map. 20701fff234dSArd Biesheuvel That memory map is required by the 2nd kernel to set up EFI virtual 20711fff234dSArd Biesheuvel mappings after kexec, but can also be used for debugging purposes. 20721fff234dSArd Biesheuvel 20731fff234dSArd Biesheuvel See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map. 20741fff234dSArd Biesheuvel 20758636a1f9SMasahiro Yamadasource "kernel/Kconfig.hz" 2076506f1d07SSam Ravnborg 20776af51380SEric DeVolderconfig ARCH_SUPPORTS_KEXEC 20786af51380SEric DeVolder def_bool y 2079506f1d07SSam Ravnborg 20806af51380SEric DeVolderconfig ARCH_SUPPORTS_KEXEC_FILE 2081c1ad12eeSArnd Bergmann def_bool X86_64 2082506f1d07SSam Ravnborg 20836af51380SEric DeVolderconfig ARCH_SELECTS_KEXEC_FILE 20846af51380SEric DeVolder def_bool y 20856af51380SEric DeVolder depends on KEXEC_FILE 2086b69a2afdSJonathan McDowell select HAVE_IMA_KEXEC if IMA 208774ca317cSVivek Goyal 2088e6265fe7SEric DeVolderconfig ARCH_SUPPORTS_KEXEC_PURGATORY 2089c1ad12eeSArnd Bergmann def_bool y 2090b799a09fSAKASHI Takahiro 20916af51380SEric DeVolderconfig ARCH_SUPPORTS_KEXEC_SIG 20926af51380SEric DeVolder def_bool y 209399d5cadfSJiri Bohac 20946af51380SEric DeVolderconfig ARCH_SUPPORTS_KEXEC_SIG_FORCE 20956af51380SEric DeVolder def_bool y 209699d5cadfSJiri Bohac 20976af51380SEric DeVolderconfig ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG 20986af51380SEric DeVolder def_bool y 209999d5cadfSJiri Bohac 21006af51380SEric DeVolderconfig ARCH_SUPPORTS_KEXEC_JUMP 21016af51380SEric DeVolder def_bool y 21028e7d8381SVivek Goyal 21036af51380SEric DeVolderconfig ARCH_SUPPORTS_CRASH_DUMP 21046af51380SEric DeVolder def_bool X86_64 || (X86_32 && HIGHMEM) 21058e7d8381SVivek Goyal 2106ea53ad9cSEric DeVolderconfig ARCH_SUPPORTS_CRASH_HOTPLUG 2107ea53ad9cSEric DeVolder def_bool y 21083ab83521SHuang Ying 21099c08a2a1SBaoquan Heconfig ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION 21109c08a2a1SBaoquan He def_bool CRASH_CORE 21119c08a2a1SBaoquan He 2112506f1d07SSam Ravnborgconfig PHYSICAL_START 21136a108a14SDavid Rientjes hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2114ceefccc9SH. Peter Anvin default "0x1000000" 2115a7f7f624SMasahiro Yamada help 2116506f1d07SSam Ravnborg This gives the physical address where the kernel is loaded. 2117506f1d07SSam Ravnborg 2118506f1d07SSam Ravnborg If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2119506f1d07SSam Ravnborg bzImage will decompress itself to above physical address and 2120506f1d07SSam Ravnborg run from there. Otherwise, bzImage will run from the address where 2121506f1d07SSam Ravnborg it has been loaded by the boot loader and will ignore above physical 2122506f1d07SSam Ravnborg address. 2123506f1d07SSam Ravnborg 2124506f1d07SSam Ravnborg In normal kdump cases one does not have to set/change this option 2125506f1d07SSam Ravnborg as now bzImage can be compiled as a completely relocatable image 2126506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2127506f1d07SSam Ravnborg address. This option is mainly useful for the folks who don't want 2128506f1d07SSam Ravnborg to use a bzImage for capturing the crash dump and want to use a 2129506f1d07SSam Ravnborg vmlinux instead. vmlinux is not relocatable hence a kernel needs 2130506f1d07SSam Ravnborg to be specifically compiled to run from a specific memory area 2131506f1d07SSam Ravnborg (normally a reserved region) and this option comes handy. 2132506f1d07SSam Ravnborg 2133ceefccc9SH. Peter Anvin So if you are using bzImage for capturing the crash dump, 2134ceefccc9SH. Peter Anvin leave the value here unchanged to 0x1000000 and set 2135ceefccc9SH. Peter Anvin CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2136ceefccc9SH. Peter Anvin for capturing the crash dump change this value to start of 2137ceefccc9SH. Peter Anvin the reserved region. In other words, it can be set based on 2138ceefccc9SH. Peter Anvin the "X" value as specified in the "crashkernel=YM@XM" 2139ceefccc9SH. Peter Anvin command line boot parameter passed to the panic-ed 2140330d4810SMauro Carvalho Chehab kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2141ceefccc9SH. Peter Anvin for more details about crash dumps. 2142506f1d07SSam Ravnborg 2143506f1d07SSam Ravnborg Usage of bzImage for capturing the crash dump is recommended as 2144506f1d07SSam Ravnborg one does not have to build two kernels. Same kernel can be used 2145506f1d07SSam Ravnborg as production kernel and capture kernel. Above option should have 2146506f1d07SSam Ravnborg gone away after relocatable bzImage support is introduced. But it 2147506f1d07SSam Ravnborg is present because there are users out there who continue to use 2148506f1d07SSam Ravnborg vmlinux for dump capture. This option should go away down the 2149506f1d07SSam Ravnborg line. 2150506f1d07SSam Ravnborg 2151506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2152506f1d07SSam Ravnborg 2153506f1d07SSam Ravnborgconfig RELOCATABLE 215426717808SH. Peter Anvin bool "Build a relocatable kernel" 215526717808SH. Peter Anvin default y 2156a7f7f624SMasahiro Yamada help 2157506f1d07SSam Ravnborg This builds a kernel image that retains relocation information 2158506f1d07SSam Ravnborg so it can be loaded someplace besides the default 1MB. 2159506f1d07SSam Ravnborg The relocations tend to make the kernel binary about 10% larger, 2160506f1d07SSam Ravnborg but are discarded at runtime. 2161506f1d07SSam Ravnborg 2162506f1d07SSam Ravnborg One use is for the kexec on panic case where the recovery kernel 2163506f1d07SSam Ravnborg must live at a different physical address than the primary 2164506f1d07SSam Ravnborg kernel. 2165506f1d07SSam Ravnborg 2166506f1d07SSam Ravnborg Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2167506f1d07SSam Ravnborg it has been loaded at and the compile time physical address 21688ab3820fSKees Cook (CONFIG_PHYSICAL_START) is used as the minimum location. 2169506f1d07SSam Ravnborg 21708ab3820fSKees Cookconfig RANDOMIZE_BASE 2171e8581e3dSBaoquan He bool "Randomize the address of the kernel image (KASLR)" 21728ab3820fSKees Cook depends on RELOCATABLE 21736807c846SIngo Molnar default y 2174a7f7f624SMasahiro Yamada help 2175e8581e3dSBaoquan He In support of Kernel Address Space Layout Randomization (KASLR), 2176e8581e3dSBaoquan He this randomizes the physical address at which the kernel image 2177e8581e3dSBaoquan He is decompressed and the virtual address where the kernel 2178e8581e3dSBaoquan He image is mapped, as a security feature that deters exploit 2179e8581e3dSBaoquan He attempts relying on knowledge of the location of kernel 2180e8581e3dSBaoquan He code internals. 2181e8581e3dSBaoquan He 2182ed9f007eSKees Cook On 64-bit, the kernel physical and virtual addresses are 2183ed9f007eSKees Cook randomized separately. The physical address will be anywhere 2184ed9f007eSKees Cook between 16MB and the top of physical memory (up to 64TB). The 2185ed9f007eSKees Cook virtual address will be randomized from 16MB up to 1GB (9 bits 2186ed9f007eSKees Cook of entropy). Note that this also reduces the memory space 2187ed9f007eSKees Cook available to kernel modules from 1.5GB to 1GB. 2188ed9f007eSKees Cook 2189ed9f007eSKees Cook On 32-bit, the kernel physical and virtual addresses are 2190ed9f007eSKees Cook randomized together. They will be randomized from 16MB up to 2191ed9f007eSKees Cook 512MB (8 bits of entropy). 21928ab3820fSKees Cook 2193a653f356SKees Cook Entropy is generated using the RDRAND instruction if it is 2194e8581e3dSBaoquan He supported. If RDTSC is supported, its value is mixed into 2195e8581e3dSBaoquan He the entropy pool as well. If neither RDRAND nor RDTSC are 2196ed9f007eSKees Cook supported, then entropy is read from the i8254 timer. The 2197ed9f007eSKees Cook usable entropy is limited by the kernel being built using 2198ed9f007eSKees Cook 2GB addressing, and that PHYSICAL_ALIGN must be at a 2199ed9f007eSKees Cook minimum of 2MB. As a result, only 10 bits of entropy are 2200ed9f007eSKees Cook theoretically possible, but the implementations are further 2201ed9f007eSKees Cook limited due to memory layouts. 2202e8581e3dSBaoquan He 22036807c846SIngo Molnar If unsure, say Y. 2204da2b6fb9SKees Cook 22058ab3820fSKees Cook# Relocation on x86 needs some additional build support 2206845adf72SH. Peter Anvinconfig X86_NEED_RELOCS 2207845adf72SH. Peter Anvin def_bool y 22088ab3820fSKees Cook depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2209845adf72SH. Peter Anvin 2210506f1d07SSam Ravnborgconfig PHYSICAL_ALIGN 2211a0215061SKees Cook hex "Alignment value to which kernel should be aligned" 22128ab3820fSKees Cook default "0x200000" 2213a0215061SKees Cook range 0x2000 0x1000000 if X86_32 2214a0215061SKees Cook range 0x200000 0x1000000 if X86_64 2215a7f7f624SMasahiro Yamada help 2216506f1d07SSam Ravnborg This value puts the alignment restrictions on physical address 2217506f1d07SSam Ravnborg where kernel is loaded and run from. Kernel is compiled for an 2218506f1d07SSam Ravnborg address which meets above alignment restriction. 2219506f1d07SSam Ravnborg 2220506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2221506f1d07SSam Ravnborg CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2222506f1d07SSam Ravnborg address aligned to above value and run from there. 2223506f1d07SSam Ravnborg 2224506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2225506f1d07SSam Ravnborg CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2226506f1d07SSam Ravnborg load address and decompress itself to the address it has been 2227506f1d07SSam Ravnborg compiled for and run from there. The address for which kernel is 2228506f1d07SSam Ravnborg compiled already meets above alignment restrictions. Hence the 2229506f1d07SSam Ravnborg end result is that kernel runs from a physical address meeting 2230506f1d07SSam Ravnborg above alignment restrictions. 2231506f1d07SSam Ravnborg 2232a0215061SKees Cook On 32-bit this value must be a multiple of 0x2000. On 64-bit 2233a0215061SKees Cook this value must be a multiple of 0x200000. 2234a0215061SKees Cook 2235506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2236506f1d07SSam Ravnborg 2237eedb92abSKirill A. Shutemovconfig DYNAMIC_MEMORY_LAYOUT 2238eedb92abSKirill A. Shutemov bool 2239a7f7f624SMasahiro Yamada help 2240eedb92abSKirill A. Shutemov This option makes base addresses of vmalloc and vmemmap as well as 2241eedb92abSKirill A. Shutemov __PAGE_OFFSET movable during boot. 2242eedb92abSKirill A. Shutemov 22430483e1faSThomas Garnierconfig RANDOMIZE_MEMORY 22440483e1faSThomas Garnier bool "Randomize the kernel memory sections" 22450483e1faSThomas Garnier depends on X86_64 22460483e1faSThomas Garnier depends on RANDOMIZE_BASE 2247eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 22480483e1faSThomas Garnier default RANDOMIZE_BASE 2249a7f7f624SMasahiro Yamada help 22500483e1faSThomas Garnier Randomizes the base virtual address of kernel memory sections 22510483e1faSThomas Garnier (physical memory mapping, vmalloc & vmemmap). This security feature 22520483e1faSThomas Garnier makes exploits relying on predictable memory locations less reliable. 22530483e1faSThomas Garnier 22540483e1faSThomas Garnier The order of allocations remains unchanged. Entropy is generated in 22550483e1faSThomas Garnier the same way as RANDOMIZE_BASE. Current implementation in the optimal 22560483e1faSThomas Garnier configuration have in average 30,000 different possible virtual 22570483e1faSThomas Garnier addresses for each memory section. 22580483e1faSThomas Garnier 22596807c846SIngo Molnar If unsure, say Y. 22600483e1faSThomas Garnier 226190397a41SThomas Garnierconfig RANDOMIZE_MEMORY_PHYSICAL_PADDING 226290397a41SThomas Garnier hex "Physical memory mapping padding" if EXPERT 226390397a41SThomas Garnier depends on RANDOMIZE_MEMORY 226490397a41SThomas Garnier default "0xa" if MEMORY_HOTPLUG 226590397a41SThomas Garnier default "0x0" 226690397a41SThomas Garnier range 0x1 0x40 if MEMORY_HOTPLUG 226790397a41SThomas Garnier range 0x0 0x40 2268a7f7f624SMasahiro Yamada help 226990397a41SThomas Garnier Define the padding in terabytes added to the existing physical 227090397a41SThomas Garnier memory size during kernel memory randomization. It is useful 227190397a41SThomas Garnier for memory hotplug support but reduces the entropy available for 227290397a41SThomas Garnier address randomization. 227390397a41SThomas Garnier 227490397a41SThomas Garnier If unsure, leave at the default value. 227590397a41SThomas Garnier 22766449dcb0SKirill A. Shutemovconfig ADDRESS_MASKING 22776449dcb0SKirill A. Shutemov bool "Linear Address Masking support" 22786449dcb0SKirill A. Shutemov depends on X86_64 22796449dcb0SKirill A. Shutemov help 22806449dcb0SKirill A. Shutemov Linear Address Masking (LAM) modifies the checking that is applied 22816449dcb0SKirill A. Shutemov to 64-bit linear addresses, allowing software to use of the 22826449dcb0SKirill A. Shutemov untranslated address bits for metadata. 22836449dcb0SKirill A. Shutemov 22846449dcb0SKirill A. Shutemov The capability can be used for efficient address sanitizers (ASAN) 22856449dcb0SKirill A. Shutemov implementation and for optimizations in JITs. 22866449dcb0SKirill A. Shutemov 2287506f1d07SSam Ravnborgconfig HOTPLUG_CPU 2288bebd024eSThomas Gleixner def_bool y 228940b31360SStephen Rothwell depends on SMP 2290506f1d07SSam Ravnborg 2291506f1d07SSam Ravnborgconfig COMPAT_VDSO 2292b0b49f26SAndy Lutomirski def_bool n 2293b0b49f26SAndy Lutomirski prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2294953fee1dSIngo Molnar depends on COMPAT_32 2295a7f7f624SMasahiro Yamada help 2296b0b49f26SAndy Lutomirski Certain buggy versions of glibc will crash if they are 2297b0b49f26SAndy Lutomirski presented with a 32-bit vDSO that is not mapped at the address 2298b0b49f26SAndy Lutomirski indicated in its segment table. 2299e84446deSRandy Dunlap 2300b0b49f26SAndy Lutomirski The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2301b0b49f26SAndy Lutomirski and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2302b0b49f26SAndy Lutomirski 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2303b0b49f26SAndy Lutomirski the only released version with the bug, but OpenSUSE 9 2304b0b49f26SAndy Lutomirski contains a buggy "glibc 2.3.2". 2305506f1d07SSam Ravnborg 2306b0b49f26SAndy Lutomirski The symptom of the bug is that everything crashes on startup, saying: 2307b0b49f26SAndy Lutomirski dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2308b0b49f26SAndy Lutomirski 2309b0b49f26SAndy Lutomirski Saying Y here changes the default value of the vdso32 boot 2310b0b49f26SAndy Lutomirski option from 1 to 0, which turns off the 32-bit vDSO entirely. 2311b0b49f26SAndy Lutomirski This works around the glibc bug but hurts performance. 2312b0b49f26SAndy Lutomirski 2313b0b49f26SAndy Lutomirski If unsure, say N: if you are compiling your own kernel, you 2314b0b49f26SAndy Lutomirski are unlikely to be using a buggy version of glibc. 2315506f1d07SSam Ravnborg 23163dc33bd3SKees Cookchoice 23173dc33bd3SKees Cook prompt "vsyscall table for legacy applications" 23183dc33bd3SKees Cook depends on X86_64 2319625b7b7fSAndy Lutomirski default LEGACY_VSYSCALL_XONLY 23203dc33bd3SKees Cook help 23213dc33bd3SKees Cook Legacy user code that does not know how to find the vDSO expects 23223dc33bd3SKees Cook to be able to issue three syscalls by calling fixed addresses in 23233dc33bd3SKees Cook kernel space. Since this location is not randomized with ASLR, 23243dc33bd3SKees Cook it can be used to assist security vulnerability exploitation. 23253dc33bd3SKees Cook 23263dc33bd3SKees Cook This setting can be changed at boot time via the kernel command 2327bf00745eSAndy Lutomirski line parameter vsyscall=[emulate|xonly|none]. Emulate mode 2328bf00745eSAndy Lutomirski is deprecated and can only be enabled using the kernel command 2329bf00745eSAndy Lutomirski line. 23303dc33bd3SKees Cook 23313dc33bd3SKees Cook On a system with recent enough glibc (2.14 or newer) and no 23323dc33bd3SKees Cook static binaries, you can say None without a performance penalty 23333dc33bd3SKees Cook to improve security. 23343dc33bd3SKees Cook 2335bd49e16eSAndy Lutomirski If unsure, select "Emulate execution only". 23363dc33bd3SKees Cook 2337bd49e16eSAndy Lutomirski config LEGACY_VSYSCALL_XONLY 2338bd49e16eSAndy Lutomirski bool "Emulate execution only" 2339bd49e16eSAndy Lutomirski help 2340bd49e16eSAndy Lutomirski The kernel traps and emulates calls into the fixed vsyscall 2341bd49e16eSAndy Lutomirski address mapping and does not allow reads. This 2342bd49e16eSAndy Lutomirski configuration is recommended when userspace might use the 2343bd49e16eSAndy Lutomirski legacy vsyscall area but support for legacy binary 2344bd49e16eSAndy Lutomirski instrumentation of legacy code is not needed. It mitigates 2345bd49e16eSAndy Lutomirski certain uses of the vsyscall area as an ASLR-bypassing 2346bd49e16eSAndy Lutomirski buffer. 23473dc33bd3SKees Cook 23483dc33bd3SKees Cook config LEGACY_VSYSCALL_NONE 23493dc33bd3SKees Cook bool "None" 23503dc33bd3SKees Cook help 23513dc33bd3SKees Cook There will be no vsyscall mapping at all. This will 23523dc33bd3SKees Cook eliminate any risk of ASLR bypass due to the vsyscall 23533dc33bd3SKees Cook fixed address mapping. Attempts to use the vsyscalls 23543dc33bd3SKees Cook will be reported to dmesg, so that either old or 23553dc33bd3SKees Cook malicious userspace programs can be identified. 23563dc33bd3SKees Cook 23573dc33bd3SKees Cookendchoice 23583dc33bd3SKees Cook 2359516cbf37STim Birdconfig CMDLINE_BOOL 2360516cbf37STim Bird bool "Built-in kernel command line" 2361a7f7f624SMasahiro Yamada help 2362516cbf37STim Bird Allow for specifying boot arguments to the kernel at 2363516cbf37STim Bird build time. On some systems (e.g. embedded ones), it is 2364516cbf37STim Bird necessary or convenient to provide some or all of the 2365516cbf37STim Bird kernel boot arguments with the kernel itself (that is, 2366516cbf37STim Bird to not rely on the boot loader to provide them.) 2367516cbf37STim Bird 2368516cbf37STim Bird To compile command line arguments into the kernel, 2369516cbf37STim Bird set this option to 'Y', then fill in the 237069711ca1SSébastien Hinderer boot arguments in CONFIG_CMDLINE. 2371516cbf37STim Bird 2372516cbf37STim Bird Systems with fully functional boot loaders (i.e. non-embedded) 2373516cbf37STim Bird should leave this option set to 'N'. 2374516cbf37STim Bird 2375516cbf37STim Birdconfig CMDLINE 2376516cbf37STim Bird string "Built-in kernel command string" 2377516cbf37STim Bird depends on CMDLINE_BOOL 2378516cbf37STim Bird default "" 2379a7f7f624SMasahiro Yamada help 2380516cbf37STim Bird Enter arguments here that should be compiled into the kernel 2381516cbf37STim Bird image and used at boot time. If the boot loader provides a 2382516cbf37STim Bird command line at boot time, it is appended to this string to 2383516cbf37STim Bird form the full kernel command line, when the system boots. 2384516cbf37STim Bird 2385516cbf37STim Bird However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2386516cbf37STim Bird change this behavior. 2387516cbf37STim Bird 2388516cbf37STim Bird In most cases, the command line (whether built-in or provided 2389516cbf37STim Bird by the boot loader) should specify the device for the root 2390516cbf37STim Bird file system. 2391516cbf37STim Bird 2392516cbf37STim Birdconfig CMDLINE_OVERRIDE 2393516cbf37STim Bird bool "Built-in command line overrides boot loader arguments" 2394645e6466SAnders Roxell depends on CMDLINE_BOOL && CMDLINE != "" 2395a7f7f624SMasahiro Yamada help 2396516cbf37STim Bird Set this option to 'Y' to have the kernel ignore the boot loader 2397516cbf37STim Bird command line, and use ONLY the built-in command line. 2398516cbf37STim Bird 2399516cbf37STim Bird This is used to work around broken boot loaders. This should 2400516cbf37STim Bird be set to 'N' under normal conditions. 2401516cbf37STim Bird 2402a5b9e5a2SAndy Lutomirskiconfig MODIFY_LDT_SYSCALL 2403a5b9e5a2SAndy Lutomirski bool "Enable the LDT (local descriptor table)" if EXPERT 2404a5b9e5a2SAndy Lutomirski default y 2405a7f7f624SMasahiro Yamada help 2406a5b9e5a2SAndy Lutomirski Linux can allow user programs to install a per-process x86 2407a5b9e5a2SAndy Lutomirski Local Descriptor Table (LDT) using the modify_ldt(2) system 2408a5b9e5a2SAndy Lutomirski call. This is required to run 16-bit or segmented code such as 2409a5b9e5a2SAndy Lutomirski DOSEMU or some Wine programs. It is also used by some very old 2410a5b9e5a2SAndy Lutomirski threading libraries. 2411a5b9e5a2SAndy Lutomirski 2412a5b9e5a2SAndy Lutomirski Enabling this feature adds a small amount of overhead to 2413a5b9e5a2SAndy Lutomirski context switches and increases the low-level kernel attack 2414a5b9e5a2SAndy Lutomirski surface. Disabling it removes the modify_ldt(2) system call. 2415a5b9e5a2SAndy Lutomirski 2416a5b9e5a2SAndy Lutomirski Saying 'N' here may make sense for embedded or server kernels. 2417a5b9e5a2SAndy Lutomirski 24183aac3ebeSThomas Gleixnerconfig STRICT_SIGALTSTACK_SIZE 24193aac3ebeSThomas Gleixner bool "Enforce strict size checking for sigaltstack" 24203aac3ebeSThomas Gleixner depends on DYNAMIC_SIGFRAME 24213aac3ebeSThomas Gleixner help 24223aac3ebeSThomas Gleixner For historical reasons MINSIGSTKSZ is a constant which became 24233aac3ebeSThomas Gleixner already too small with AVX512 support. Add a mechanism to 24243aac3ebeSThomas Gleixner enforce strict checking of the sigaltstack size against the 24253aac3ebeSThomas Gleixner real size of the FPU frame. This option enables the check 24263aac3ebeSThomas Gleixner by default. It can also be controlled via the kernel command 24273aac3ebeSThomas Gleixner line option 'strict_sas_size' independent of this config 24283aac3ebeSThomas Gleixner switch. Enabling it might break existing applications which 24293aac3ebeSThomas Gleixner allocate a too small sigaltstack but 'work' because they 24303aac3ebeSThomas Gleixner never get a signal delivered. 24313aac3ebeSThomas Gleixner 24323aac3ebeSThomas Gleixner Say 'N' unless you want to really enforce this check. 24333aac3ebeSThomas Gleixner 2434b700e7f0SSeth Jenningssource "kernel/livepatch/Kconfig" 2435b700e7f0SSeth Jennings 2436506f1d07SSam Ravnborgendmenu 2437506f1d07SSam Ravnborg 24381ca3683cSUros Bizjakconfig CC_HAS_NAMED_AS 24391ca3683cSUros Bizjak def_bool CC_IS_GCC && GCC_VERSION >= 120100 24401ca3683cSUros Bizjak 24411ca3683cSUros Bizjakconfig USE_X86_SEG_SUPPORT 24421ca3683cSUros Bizjak def_bool y 2443e29aad08SUros Bizjak depends on CC_HAS_NAMED_AS 2444e29aad08SUros Bizjak # 2445e29aad08SUros Bizjak # -fsanitize=kernel-address (KASAN) is at the moment incompatible 2446e29aad08SUros Bizjak # with named address spaces - see GCC PR sanitizer/111736. 2447e29aad08SUros Bizjak # 2448e29aad08SUros Bizjak depends on !KASAN 24491ca3683cSUros Bizjak 2450f43b9876SPeter Zijlstraconfig CC_HAS_SLS 2451f43b9876SPeter Zijlstra def_bool $(cc-option,-mharden-sls=all) 2452f43b9876SPeter Zijlstra 2453f43b9876SPeter Zijlstraconfig CC_HAS_RETURN_THUNK 2454f43b9876SPeter Zijlstra def_bool $(cc-option,-mfunction-return=thunk-extern) 2455f43b9876SPeter Zijlstra 2456bea75b33SThomas Gleixnerconfig CC_HAS_ENTRY_PADDING 2457bea75b33SThomas Gleixner def_bool $(cc-option,-fpatchable-function-entry=16,16) 2458bea75b33SThomas Gleixner 2459bea75b33SThomas Gleixnerconfig FUNCTION_PADDING_CFI 2460bea75b33SThomas Gleixner int 2461bea75b33SThomas Gleixner default 59 if FUNCTION_ALIGNMENT_64B 2462bea75b33SThomas Gleixner default 27 if FUNCTION_ALIGNMENT_32B 2463bea75b33SThomas Gleixner default 11 if FUNCTION_ALIGNMENT_16B 2464bea75b33SThomas Gleixner default 3 if FUNCTION_ALIGNMENT_8B 2465bea75b33SThomas Gleixner default 0 2466bea75b33SThomas Gleixner 2467bea75b33SThomas Gleixner# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG 2468bea75b33SThomas Gleixner# except Kconfig can't do arithmetic :/ 2469bea75b33SThomas Gleixnerconfig FUNCTION_PADDING_BYTES 2470bea75b33SThomas Gleixner int 2471bea75b33SThomas Gleixner default FUNCTION_PADDING_CFI if CFI_CLANG 2472bea75b33SThomas Gleixner default FUNCTION_ALIGNMENT 2473bea75b33SThomas Gleixner 2474931ab636SPeter Zijlstraconfig CALL_PADDING 2475931ab636SPeter Zijlstra def_bool n 2476931ab636SPeter Zijlstra depends on CC_HAS_ENTRY_PADDING && OBJTOOL 2477931ab636SPeter Zijlstra select FUNCTION_ALIGNMENT_16B 2478931ab636SPeter Zijlstra 2479931ab636SPeter Zijlstraconfig FINEIBT 2480931ab636SPeter Zijlstra def_bool y 2481aefb2f2eSBreno Leitao depends on X86_KERNEL_IBT && CFI_CLANG && MITIGATION_RETPOLINE 2482931ab636SPeter Zijlstra select CALL_PADDING 2483931ab636SPeter Zijlstra 24848f7c0d8bSThomas Gleixnerconfig HAVE_CALL_THUNKS 24858f7c0d8bSThomas Gleixner def_bool y 24860911b8c5SBreno Leitao depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL 24878f7c0d8bSThomas Gleixner 24888f7c0d8bSThomas Gleixnerconfig CALL_THUNKS 24898f7c0d8bSThomas Gleixner def_bool n 2490931ab636SPeter Zijlstra select CALL_PADDING 24918f7c0d8bSThomas Gleixner 2492b341b20dSPeter Zijlstraconfig PREFIX_SYMBOLS 2493b341b20dSPeter Zijlstra def_bool y 2494931ab636SPeter Zijlstra depends on CALL_PADDING && !CFI_CLANG 2495b341b20dSPeter Zijlstra 2496f43b9876SPeter Zijlstramenuconfig SPECULATION_MITIGATIONS 2497f43b9876SPeter Zijlstra bool "Mitigations for speculative execution vulnerabilities" 2498f43b9876SPeter Zijlstra default y 2499f43b9876SPeter Zijlstra help 2500f43b9876SPeter Zijlstra Say Y here to enable options which enable mitigations for 2501f43b9876SPeter Zijlstra speculative execution hardware vulnerabilities. 2502f43b9876SPeter Zijlstra 2503f43b9876SPeter Zijlstra If you say N, all mitigations will be disabled. You really 2504f43b9876SPeter Zijlstra should know what you are doing to say so. 2505f43b9876SPeter Zijlstra 2506f43b9876SPeter Zijlstraif SPECULATION_MITIGATIONS 2507f43b9876SPeter Zijlstra 2508ea4654e0SBreno Leitaoconfig MITIGATION_PAGE_TABLE_ISOLATION 2509f43b9876SPeter Zijlstra bool "Remove the kernel mapping in user mode" 2510f43b9876SPeter Zijlstra default y 2511f43b9876SPeter Zijlstra depends on (X86_64 || X86_PAE) 2512f43b9876SPeter Zijlstra help 2513f43b9876SPeter Zijlstra This feature reduces the number of hardware side channels by 2514f43b9876SPeter Zijlstra ensuring that the majority of kernel addresses are not mapped 2515f43b9876SPeter Zijlstra into userspace. 2516f43b9876SPeter Zijlstra 2517ff61f079SJonathan Corbet See Documentation/arch/x86/pti.rst for more details. 2518f43b9876SPeter Zijlstra 2519aefb2f2eSBreno Leitaoconfig MITIGATION_RETPOLINE 2520f43b9876SPeter Zijlstra bool "Avoid speculative indirect branches in kernel" 2521f43b9876SPeter Zijlstra select OBJTOOL if HAVE_OBJTOOL 2522f43b9876SPeter Zijlstra default y 2523f43b9876SPeter Zijlstra help 2524f43b9876SPeter Zijlstra Compile kernel with the retpoline compiler options to guard against 2525f43b9876SPeter Zijlstra kernel-to-user data leaks by avoiding speculative indirect 2526f43b9876SPeter Zijlstra branches. Requires a compiler with -mindirect-branch=thunk-extern 2527f43b9876SPeter Zijlstra support for full protection. The kernel may run slower. 2528f43b9876SPeter Zijlstra 25290911b8c5SBreno Leitaoconfig MITIGATION_RETHUNK 2530f43b9876SPeter Zijlstra bool "Enable return-thunks" 2531aefb2f2eSBreno Leitao depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK 2532f43b9876SPeter Zijlstra select OBJTOOL if HAVE_OBJTOOL 2533b648ab48SBen Hutchings default y if X86_64 2534f43b9876SPeter Zijlstra help 2535f43b9876SPeter Zijlstra Compile the kernel with the return-thunks compiler option to guard 2536f43b9876SPeter Zijlstra against kernel-to-user data leaks by avoiding return speculation. 2537f43b9876SPeter Zijlstra Requires a compiler with -mfunction-return=thunk-extern 2538f43b9876SPeter Zijlstra support for full protection. The kernel may run slower. 2539f43b9876SPeter Zijlstra 2540ac61d439SBreno Leitaoconfig MITIGATION_UNRET_ENTRY 2541f43b9876SPeter Zijlstra bool "Enable UNRET on kernel entry" 25420911b8c5SBreno Leitao depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64 2543f43b9876SPeter Zijlstra default y 2544f43b9876SPeter Zijlstra help 2545f43b9876SPeter Zijlstra Compile the kernel with support for the retbleed=unret mitigation. 2546f43b9876SPeter Zijlstra 25475fa31af3SBreno Leitaoconfig MITIGATION_CALL_DEPTH_TRACKING 254880e4c1cdSThomas Gleixner bool "Mitigate RSB underflow with call depth tracking" 254980e4c1cdSThomas Gleixner depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS 255080e4c1cdSThomas Gleixner select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 255180e4c1cdSThomas Gleixner select CALL_THUNKS 255280e4c1cdSThomas Gleixner default y 255380e4c1cdSThomas Gleixner help 255480e4c1cdSThomas Gleixner Compile the kernel with call depth tracking to mitigate the Intel 255580e4c1cdSThomas Gleixner SKL Return-Speculation-Buffer (RSB) underflow issue. The 255680e4c1cdSThomas Gleixner mitigation is off by default and needs to be enabled on the 255780e4c1cdSThomas Gleixner kernel command line via the retbleed=stuff option. For 255880e4c1cdSThomas Gleixner non-affected systems the overhead of this option is marginal as 255980e4c1cdSThomas Gleixner the call depth tracking is using run-time generated call thunks 256080e4c1cdSThomas Gleixner in a compiler generated padding area and call patching. This 256180e4c1cdSThomas Gleixner increases text size by ~5%. For non affected systems this space 256280e4c1cdSThomas Gleixner is unused. On affected SKL systems this results in a significant 256380e4c1cdSThomas Gleixner performance gain over the IBRS mitigation. 256480e4c1cdSThomas Gleixner 2565e81dc127SThomas Gleixnerconfig CALL_THUNKS_DEBUG 2566e81dc127SThomas Gleixner bool "Enable call thunks and call depth tracking debugging" 25675fa31af3SBreno Leitao depends on MITIGATION_CALL_DEPTH_TRACKING 2568e81dc127SThomas Gleixner select FUNCTION_ALIGNMENT_32B 2569e81dc127SThomas Gleixner default n 2570e81dc127SThomas Gleixner help 2571e81dc127SThomas Gleixner Enable call/ret counters for imbalance detection and build in 2572e81dc127SThomas Gleixner a noisy dmesg about callthunks generation and call patching for 2573e81dc127SThomas Gleixner trouble shooting. The debug prints need to be enabled on the 2574e81dc127SThomas Gleixner kernel command line with 'debug-callthunks'. 257554628de6SRandy Dunlap Only enable this when you are debugging call thunks as this 257654628de6SRandy Dunlap creates a noticeable runtime overhead. If unsure say N. 257780e4c1cdSThomas Gleixner 2578e0b8fcfaSBreno Leitaoconfig MITIGATION_IBPB_ENTRY 2579f43b9876SPeter Zijlstra bool "Enable IBPB on kernel entry" 2580b648ab48SBen Hutchings depends on CPU_SUP_AMD && X86_64 2581f43b9876SPeter Zijlstra default y 2582f43b9876SPeter Zijlstra help 2583f43b9876SPeter Zijlstra Compile the kernel with support for the retbleed=ibpb mitigation. 2584f43b9876SPeter Zijlstra 25851da8d217SBreno Leitaoconfig MITIGATION_IBRS_ENTRY 2586f43b9876SPeter Zijlstra bool "Enable IBRS on kernel entry" 2587b648ab48SBen Hutchings depends on CPU_SUP_INTEL && X86_64 2588f43b9876SPeter Zijlstra default y 2589f43b9876SPeter Zijlstra help 2590f43b9876SPeter Zijlstra Compile the kernel with support for the spectre_v2=ibrs mitigation. 2591f43b9876SPeter Zijlstra This mitigates both spectre_v2 and retbleed at great cost to 2592f43b9876SPeter Zijlstra performance. 2593f43b9876SPeter Zijlstra 2594a033eec9SBreno Leitaoconfig MITIGATION_SRSO 2595fb3bd914SBorislav Petkov (AMD) bool "Mitigate speculative RAS overflow on AMD" 25960911b8c5SBreno Leitao depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK 2597fb3bd914SBorislav Petkov (AMD) default y 2598fb3bd914SBorislav Petkov (AMD) help 2599fb3bd914SBorislav Petkov (AMD) Enable the SRSO mitigation needed on AMD Zen1-4 machines. 2600fb3bd914SBorislav Petkov (AMD) 26017b75782fSBreno Leitaoconfig MITIGATION_SLS 2602f43b9876SPeter Zijlstra bool "Mitigate Straight-Line-Speculation" 2603f43b9876SPeter Zijlstra depends on CC_HAS_SLS && X86_64 2604f43b9876SPeter Zijlstra select OBJTOOL if HAVE_OBJTOOL 2605f43b9876SPeter Zijlstra default n 2606f43b9876SPeter Zijlstra help 2607f43b9876SPeter Zijlstra Compile the kernel with straight-line-speculation options to guard 2608f43b9876SPeter Zijlstra against straight line speculation. The kernel image might be slightly 2609f43b9876SPeter Zijlstra larger. 2610f43b9876SPeter Zijlstra 2611be83e809SBreno Leitaoconfig MITIGATION_GDS_FORCE 261253cf5797SDaniel Sneddon bool "Force GDS Mitigation" 261353cf5797SDaniel Sneddon depends on CPU_SUP_INTEL 261453cf5797SDaniel Sneddon default n 261553cf5797SDaniel Sneddon help 261653cf5797SDaniel Sneddon Gather Data Sampling (GDS) is a hardware vulnerability which allows 261753cf5797SDaniel Sneddon unprivileged speculative access to data which was previously stored in 261853cf5797SDaniel Sneddon vector registers. 261953cf5797SDaniel Sneddon 262053cf5797SDaniel Sneddon This option is equivalent to setting gather_data_sampling=force on the 262153cf5797SDaniel Sneddon command line. The microcode mitigation is used if present, otherwise 262253cf5797SDaniel Sneddon AVX is disabled as a mitigation. On affected systems that are missing 262353cf5797SDaniel Sneddon the microcode any userspace code that unconditionally uses AVX will 262453cf5797SDaniel Sneddon break with this option set. 262553cf5797SDaniel Sneddon 262653cf5797SDaniel Sneddon Setting this option on systems not vulnerable to GDS has no effect. 262753cf5797SDaniel Sneddon 262853cf5797SDaniel Sneddon If in doubt, say N. 262953cf5797SDaniel Sneddon 2630f43b9876SPeter Zijlstraendif 2631f43b9876SPeter Zijlstra 26323072e413SMichal Hockoconfig ARCH_HAS_ADD_PAGES 26333072e413SMichal Hocko def_bool y 26345c11f00bSDavid Hildenbrand depends on ARCH_ENABLE_MEMORY_HOTPLUG 26353072e413SMichal Hocko 2636da85f865SBjorn Helgaasmenu "Power management and ACPI options" 2637e279b6c1SSam Ravnborg 2638e279b6c1SSam Ravnborgconfig ARCH_HIBERNATION_HEADER 26393c2362e6SHarvey Harrison def_bool y 264044556530SZhimin Gu depends on HIBERNATION 2641e279b6c1SSam Ravnborg 2642e279b6c1SSam Ravnborgsource "kernel/power/Kconfig" 2643e279b6c1SSam Ravnborg 2644e279b6c1SSam Ravnborgsource "drivers/acpi/Kconfig" 2645e279b6c1SSam Ravnborg 2646a6b68076SAndi Kleenconfig X86_APM_BOOT 26476fc108a0SJan Beulich def_bool y 2648282e5aabSPaul Bolle depends on APM 2649a6b68076SAndi Kleen 2650e279b6c1SSam Ravnborgmenuconfig APM 2651e279b6c1SSam Ravnborg tristate "APM (Advanced Power Management) BIOS support" 2652efefa6f6SIngo Molnar depends on X86_32 && PM_SLEEP 2653a7f7f624SMasahiro Yamada help 2654e279b6c1SSam Ravnborg APM is a BIOS specification for saving power using several different 2655e279b6c1SSam Ravnborg techniques. This is mostly useful for battery powered laptops with 2656e279b6c1SSam Ravnborg APM compliant BIOSes. If you say Y here, the system time will be 2657e279b6c1SSam Ravnborg reset after a RESUME operation, the /proc/apm device will provide 2658e279b6c1SSam Ravnborg battery status information, and user-space programs will receive 2659e279b6c1SSam Ravnborg notification of APM "events" (e.g. battery status change). 2660e279b6c1SSam Ravnborg 2661e279b6c1SSam Ravnborg If you select "Y" here, you can disable actual use of the APM 2662e279b6c1SSam Ravnborg BIOS by passing the "apm=off" option to the kernel at boot time. 2663e279b6c1SSam Ravnborg 2664e279b6c1SSam Ravnborg Note that the APM support is almost completely disabled for 2665e279b6c1SSam Ravnborg machines with more than one CPU. 2666e279b6c1SSam Ravnborg 2667e279b6c1SSam Ravnborg In order to use APM, you will need supporting software. For location 2668151f4e2bSMauro Carvalho Chehab and more information, read <file:Documentation/power/apm-acpi.rst> 26692dc98fd3SMichael Witten and the Battery Powered Linux mini-HOWTO, available from 2670e279b6c1SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 2671e279b6c1SSam Ravnborg 2672e279b6c1SSam Ravnborg This driver does not spin down disk drives (see the hdparm(8) 2673e279b6c1SSam Ravnborg manpage ("man 8 hdparm") for that), and it doesn't turn off 2674e279b6c1SSam Ravnborg VESA-compliant "green" monitors. 2675e279b6c1SSam Ravnborg 2676e279b6c1SSam Ravnborg This driver does not support the TI 4000M TravelMate and the ACER 2677e279b6c1SSam Ravnborg 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2678e279b6c1SSam Ravnborg desktop machines also don't have compliant BIOSes, and this driver 2679e279b6c1SSam Ravnborg may cause those machines to panic during the boot phase. 2680e279b6c1SSam Ravnborg 2681e279b6c1SSam Ravnborg Generally, if you don't have a battery in your machine, there isn't 2682e279b6c1SSam Ravnborg much point in using this driver and you should say N. If you get 2683e279b6c1SSam Ravnborg random kernel OOPSes or reboots that don't seem to be related to 2684e279b6c1SSam Ravnborg anything, try disabling/enabling this option (or disabling/enabling 2685e279b6c1SSam Ravnborg APM in your BIOS). 2686e279b6c1SSam Ravnborg 2687e279b6c1SSam Ravnborg Some other things you should try when experiencing seemingly random, 2688e279b6c1SSam Ravnborg "weird" problems: 2689e279b6c1SSam Ravnborg 2690e279b6c1SSam Ravnborg 1) make sure that you have enough swap space and that it is 2691e279b6c1SSam Ravnborg enabled. 26927987448fSStephen Kitt 2) pass the "idle=poll" option to the kernel 2693e279b6c1SSam Ravnborg 3) switch on floating point emulation in the kernel and pass 2694e279b6c1SSam Ravnborg the "no387" option to the kernel 2695e279b6c1SSam Ravnborg 4) pass the "floppy=nodma" option to the kernel 2696e279b6c1SSam Ravnborg 5) pass the "mem=4M" option to the kernel (thereby disabling 2697e279b6c1SSam Ravnborg all but the first 4 MB of RAM) 2698e279b6c1SSam Ravnborg 6) make sure that the CPU is not over clocked. 2699e279b6c1SSam Ravnborg 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2700e279b6c1SSam Ravnborg 8) disable the cache from your BIOS settings 2701e279b6c1SSam Ravnborg 9) install a fan for the video card or exchange video RAM 2702e279b6c1SSam Ravnborg 10) install a better fan for the CPU 2703e279b6c1SSam Ravnborg 11) exchange RAM chips 2704e279b6c1SSam Ravnborg 12) exchange the motherboard. 2705e279b6c1SSam Ravnborg 2706e279b6c1SSam Ravnborg To compile this driver as a module, choose M here: the 2707e279b6c1SSam Ravnborg module will be called apm. 2708e279b6c1SSam Ravnborg 2709e279b6c1SSam Ravnborgif APM 2710e279b6c1SSam Ravnborg 2711e279b6c1SSam Ravnborgconfig APM_IGNORE_USER_SUSPEND 2712e279b6c1SSam Ravnborg bool "Ignore USER SUSPEND" 2713a7f7f624SMasahiro Yamada help 2714e279b6c1SSam Ravnborg This option will ignore USER SUSPEND requests. On machines with a 2715e279b6c1SSam Ravnborg compliant APM BIOS, you want to say N. However, on the NEC Versa M 2716e279b6c1SSam Ravnborg series notebooks, it is necessary to say Y because of a BIOS bug. 2717e279b6c1SSam Ravnborg 2718e279b6c1SSam Ravnborgconfig APM_DO_ENABLE 2719e279b6c1SSam Ravnborg bool "Enable PM at boot time" 2720a7f7f624SMasahiro Yamada help 2721e279b6c1SSam Ravnborg Enable APM features at boot time. From page 36 of the APM BIOS 2722e279b6c1SSam Ravnborg specification: "When disabled, the APM BIOS does not automatically 2723e279b6c1SSam Ravnborg power manage devices, enter the Standby State, enter the Suspend 2724e279b6c1SSam Ravnborg State, or take power saving steps in response to CPU Idle calls." 2725e279b6c1SSam Ravnborg This driver will make CPU Idle calls when Linux is idle (unless this 2726e279b6c1SSam Ravnborg feature is turned off -- see "Do CPU IDLE calls", below). This 2727e279b6c1SSam Ravnborg should always save battery power, but more complicated APM features 2728e279b6c1SSam Ravnborg will be dependent on your BIOS implementation. You may need to turn 2729e279b6c1SSam Ravnborg this option off if your computer hangs at boot time when using APM 2730e279b6c1SSam Ravnborg support, or if it beeps continuously instead of suspending. Turn 2731e279b6c1SSam Ravnborg this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2732e279b6c1SSam Ravnborg T400CDT. This is off by default since most machines do fine without 2733e279b6c1SSam Ravnborg this feature. 2734e279b6c1SSam Ravnborg 2735e279b6c1SSam Ravnborgconfig APM_CPU_IDLE 2736dd8af076SLen Brown depends on CPU_IDLE 2737e279b6c1SSam Ravnborg bool "Make CPU Idle calls when idle" 2738a7f7f624SMasahiro Yamada help 2739e279b6c1SSam Ravnborg Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2740e279b6c1SSam Ravnborg On some machines, this can activate improved power savings, such as 2741e279b6c1SSam Ravnborg a slowed CPU clock rate, when the machine is idle. These idle calls 2742e279b6c1SSam Ravnborg are made after the idle loop has run for some length of time (e.g., 2743e279b6c1SSam Ravnborg 333 mS). On some machines, this will cause a hang at boot time or 2744e279b6c1SSam Ravnborg whenever the CPU becomes idle. (On machines with more than one CPU, 2745e279b6c1SSam Ravnborg this option does nothing.) 2746e279b6c1SSam Ravnborg 2747e279b6c1SSam Ravnborgconfig APM_DISPLAY_BLANK 2748e279b6c1SSam Ravnborg bool "Enable console blanking using APM" 2749a7f7f624SMasahiro Yamada help 2750e279b6c1SSam Ravnborg Enable console blanking using the APM. Some laptops can use this to 2751e279b6c1SSam Ravnborg turn off the LCD backlight when the screen blanker of the Linux 2752e279b6c1SSam Ravnborg virtual console blanks the screen. Note that this is only used by 2753e279b6c1SSam Ravnborg the virtual console screen blanker, and won't turn off the backlight 2754e279b6c1SSam Ravnborg when using the X Window system. This also doesn't have anything to 2755e279b6c1SSam Ravnborg do with your VESA-compliant power-saving monitor. Further, this 2756e279b6c1SSam Ravnborg option doesn't work for all laptops -- it might not turn off your 2757e279b6c1SSam Ravnborg backlight at all, or it might print a lot of errors to the console, 2758e279b6c1SSam Ravnborg especially if you are using gpm. 2759e279b6c1SSam Ravnborg 2760e279b6c1SSam Ravnborgconfig APM_ALLOW_INTS 2761e279b6c1SSam Ravnborg bool "Allow interrupts during APM BIOS calls" 2762a7f7f624SMasahiro Yamada help 2763e279b6c1SSam Ravnborg Normally we disable external interrupts while we are making calls to 2764e279b6c1SSam Ravnborg the APM BIOS as a measure to lessen the effects of a badly behaving 2765e279b6c1SSam Ravnborg BIOS implementation. The BIOS should reenable interrupts if it 2766e279b6c1SSam Ravnborg needs to. Unfortunately, some BIOSes do not -- especially those in 2767e279b6c1SSam Ravnborg many of the newer IBM Thinkpads. If you experience hangs when you 2768e279b6c1SSam Ravnborg suspend, try setting this to Y. Otherwise, say N. 2769e279b6c1SSam Ravnborg 2770e279b6c1SSam Ravnborgendif # APM 2771e279b6c1SSam Ravnborg 2772bb0a56ecSDave Jonessource "drivers/cpufreq/Kconfig" 2773e279b6c1SSam Ravnborg 2774e279b6c1SSam Ravnborgsource "drivers/cpuidle/Kconfig" 2775e279b6c1SSam Ravnborg 277627471fdbSAndy Henroidsource "drivers/idle/Kconfig" 277727471fdbSAndy Henroid 2778e279b6c1SSam Ravnborgendmenu 2779e279b6c1SSam Ravnborg 2780e279b6c1SSam Ravnborgmenu "Bus options (PCI etc.)" 2781e279b6c1SSam Ravnborg 2782e279b6c1SSam Ravnborgchoice 2783e279b6c1SSam Ravnborg prompt "PCI access mode" 2784efefa6f6SIngo Molnar depends on X86_32 && PCI 2785e279b6c1SSam Ravnborg default PCI_GOANY 2786a7f7f624SMasahiro Yamada help 2787e279b6c1SSam Ravnborg On PCI systems, the BIOS can be used to detect the PCI devices and 2788e279b6c1SSam Ravnborg determine their configuration. However, some old PCI motherboards 2789e279b6c1SSam Ravnborg have BIOS bugs and may crash if this is done. Also, some embedded 2790e279b6c1SSam Ravnborg PCI-based systems don't have any BIOS at all. Linux can also try to 2791e279b6c1SSam Ravnborg detect the PCI hardware directly without using the BIOS. 2792e279b6c1SSam Ravnborg 2793e279b6c1SSam Ravnborg With this option, you can specify how Linux should detect the 2794e279b6c1SSam Ravnborg PCI devices. If you choose "BIOS", the BIOS will be used, 2795e279b6c1SSam Ravnborg if you choose "Direct", the BIOS won't be used, and if you 2796e279b6c1SSam Ravnborg choose "MMConfig", then PCI Express MMCONFIG will be used. 2797e279b6c1SSam Ravnborg If you choose "Any", the kernel will try MMCONFIG, then the 2798e279b6c1SSam Ravnborg direct access method and falls back to the BIOS if that doesn't 2799e279b6c1SSam Ravnborg work. If unsure, go with the default, which is "Any". 2800e279b6c1SSam Ravnborg 2801e279b6c1SSam Ravnborgconfig PCI_GOBIOS 2802e279b6c1SSam Ravnborg bool "BIOS" 2803e279b6c1SSam Ravnborg 2804e279b6c1SSam Ravnborgconfig PCI_GOMMCONFIG 2805e279b6c1SSam Ravnborg bool "MMConfig" 2806e279b6c1SSam Ravnborg 2807e279b6c1SSam Ravnborgconfig PCI_GODIRECT 2808e279b6c1SSam Ravnborg bool "Direct" 2809e279b6c1SSam Ravnborg 28103ef0e1f8SAndres Salomonconfig PCI_GOOLPC 281176fb6570SDaniel Drake bool "OLPC XO-1" 28123ef0e1f8SAndres Salomon depends on OLPC 28133ef0e1f8SAndres Salomon 28142bdd1b03SAndres Salomonconfig PCI_GOANY 28152bdd1b03SAndres Salomon bool "Any" 28162bdd1b03SAndres Salomon 2817e279b6c1SSam Ravnborgendchoice 2818e279b6c1SSam Ravnborg 2819e279b6c1SSam Ravnborgconfig PCI_BIOS 28203c2362e6SHarvey Harrison def_bool y 2821efefa6f6SIngo Molnar depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2822e279b6c1SSam Ravnborg 2823e279b6c1SSam Ravnborg# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2824e279b6c1SSam Ravnborgconfig PCI_DIRECT 28253c2362e6SHarvey Harrison def_bool y 28260aba496fSShaohua Li depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2827e279b6c1SSam Ravnborg 2828e279b6c1SSam Ravnborgconfig PCI_MMCONFIG 2829b45c9f36SJan Kiszka bool "Support mmconfig PCI config space access" if X86_64 2830b45c9f36SJan Kiszka default y 28314590d98fSAndy Shevchenko depends on PCI && (ACPI || JAILHOUSE_GUEST) 2832b45c9f36SJan Kiszka depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2833e279b6c1SSam Ravnborg 28343ef0e1f8SAndres Salomonconfig PCI_OLPC 28352bdd1b03SAndres Salomon def_bool y 28362bdd1b03SAndres Salomon depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 28373ef0e1f8SAndres Salomon 2838b5401a96SAlex Nixonconfig PCI_XEN 2839b5401a96SAlex Nixon def_bool y 2840b5401a96SAlex Nixon depends on PCI && XEN 2841b5401a96SAlex Nixon 28428364e1f8SJan Kiszkaconfig MMCONF_FAM10H 28438364e1f8SJan Kiszka def_bool y 28448364e1f8SJan Kiszka depends on X86_64 && PCI_MMCONFIG && ACPI 2845e279b6c1SSam Ravnborg 28463f6ea84aSIra W. Snyderconfig PCI_CNB20LE_QUIRK 28476a108a14SDavid Rientjes bool "Read CNB20LE Host Bridge Windows" if EXPERT 28486ea30386SKees Cook depends on PCI 28493f6ea84aSIra W. Snyder help 28503f6ea84aSIra W. Snyder Read the PCI windows out of the CNB20LE host bridge. This allows 28513f6ea84aSIra W. Snyder PCI hotplug to work on systems with the CNB20LE chipset which do 28523f6ea84aSIra W. Snyder not have ACPI. 28533f6ea84aSIra W. Snyder 285464a5fed6SBjorn Helgaas There's no public spec for this chipset, and this functionality 285564a5fed6SBjorn Helgaas is known to be incomplete. 285664a5fed6SBjorn Helgaas 285764a5fed6SBjorn Helgaas You should say N unless you know you need this. 285864a5fed6SBjorn Helgaas 28593a495511SWilliam Breathitt Grayconfig ISA_BUS 286017a2a129SWilliam Breathitt Gray bool "ISA bus support on modern systems" if EXPERT 28613a495511SWilliam Breathitt Gray help 286217a2a129SWilliam Breathitt Gray Expose ISA bus device drivers and options available for selection and 286317a2a129SWilliam Breathitt Gray configuration. Enable this option if your target machine has an ISA 286417a2a129SWilliam Breathitt Gray bus. ISA is an older system, displaced by PCI and newer bus 286517a2a129SWilliam Breathitt Gray architectures -- if your target machine is modern, it probably does 286617a2a129SWilliam Breathitt Gray not have an ISA bus. 28673a495511SWilliam Breathitt Gray 28683a495511SWilliam Breathitt Gray If unsure, say N. 28693a495511SWilliam Breathitt Gray 28701c00f016SDavid Rientjes# x86_64 have no ISA slots, but can have ISA-style DMA. 2871e279b6c1SSam Ravnborgconfig ISA_DMA_API 28721c00f016SDavid Rientjes bool "ISA-style DMA support" if (X86_64 && EXPERT) 28731c00f016SDavid Rientjes default y 28741c00f016SDavid Rientjes help 28751c00f016SDavid Rientjes Enables ISA-style DMA support for devices requiring such controllers. 28761c00f016SDavid Rientjes If unsure, say Y. 2877e279b6c1SSam Ravnborg 287851e68d05SLinus Torvaldsif X86_32 287951e68d05SLinus Torvalds 2880e279b6c1SSam Ravnborgconfig ISA 2881e279b6c1SSam Ravnborg bool "ISA support" 2882a7f7f624SMasahiro Yamada help 2883e279b6c1SSam Ravnborg Find out whether you have ISA slots on your motherboard. ISA is the 2884e279b6c1SSam Ravnborg name of a bus system, i.e. the way the CPU talks to the other stuff 2885e279b6c1SSam Ravnborg inside your box. Other bus systems are PCI, EISA, MicroChannel 2886e279b6c1SSam Ravnborg (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2887e279b6c1SSam Ravnborg newer boards don't support it. If you have ISA, say Y, otherwise N. 2888e279b6c1SSam Ravnborg 2889e279b6c1SSam Ravnborgconfig SCx200 2890e279b6c1SSam Ravnborg tristate "NatSemi SCx200 support" 2891a7f7f624SMasahiro Yamada help 2892e279b6c1SSam Ravnborg This provides basic support for National Semiconductor's 2893e279b6c1SSam Ravnborg (now AMD's) Geode processors. The driver probes for the 2894e279b6c1SSam Ravnborg PCI-IDs of several on-chip devices, so its a good dependency 2895e279b6c1SSam Ravnborg for other scx200_* drivers. 2896e279b6c1SSam Ravnborg 2897e279b6c1SSam Ravnborg If compiled as a module, the driver is named scx200. 2898e279b6c1SSam Ravnborg 2899e279b6c1SSam Ravnborgconfig SCx200HR_TIMER 2900e279b6c1SSam Ravnborg tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2901592913ecSJohn Stultz depends on SCx200 2902e279b6c1SSam Ravnborg default y 2903a7f7f624SMasahiro Yamada help 2904e279b6c1SSam Ravnborg This driver provides a clocksource built upon the on-chip 2905e279b6c1SSam Ravnborg 27MHz high-resolution timer. Its also a workaround for 2906e279b6c1SSam Ravnborg NSC Geode SC-1100's buggy TSC, which loses time when the 2907e279b6c1SSam Ravnborg processor goes idle (as is done by the scheduler). The 2908e279b6c1SSam Ravnborg other workaround is idle=poll boot option. 2909e279b6c1SSam Ravnborg 29103ef0e1f8SAndres Salomonconfig OLPC 29113ef0e1f8SAndres Salomon bool "One Laptop Per Child support" 291254008979SThomas Gleixner depends on !X86_PAE 29133c554946SAndres Salomon select GPIOLIB 2914dc3119e7SThomas Gleixner select OF 291545bb1674SDaniel Drake select OF_PROMTREE 2916b4e51854SGrant Likely select IRQ_DOMAIN 29170c3d931bSLubomir Rintel select OLPC_EC 2918a7f7f624SMasahiro Yamada help 29193ef0e1f8SAndres Salomon Add support for detecting the unique features of the OLPC 29203ef0e1f8SAndres Salomon XO hardware. 29213ef0e1f8SAndres Salomon 2922a3128588SDaniel Drakeconfig OLPC_XO1_PM 2923a3128588SDaniel Drake bool "OLPC XO-1 Power Management" 2924fa112cf1SBorislav Petkov depends on OLPC && MFD_CS5535=y && PM_SLEEP 2925a7f7f624SMasahiro Yamada help 292697c4cb71SDaniel Drake Add support for poweroff and suspend of the OLPC XO-1 laptop. 2927bf1ebf00SDaniel Drake 2928cfee9597SDaniel Drakeconfig OLPC_XO1_RTC 2929cfee9597SDaniel Drake bool "OLPC XO-1 Real Time Clock" 2930cfee9597SDaniel Drake depends on OLPC_XO1_PM && RTC_DRV_CMOS 2931a7f7f624SMasahiro Yamada help 2932cfee9597SDaniel Drake Add support for the XO-1 real time clock, which can be used as a 2933cfee9597SDaniel Drake programmable wakeup source. 2934cfee9597SDaniel Drake 29357feda8e9SDaniel Drakeconfig OLPC_XO1_SCI 29367feda8e9SDaniel Drake bool "OLPC XO-1 SCI extras" 293792e830f2SArnd Bergmann depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2938ed8e47feSRandy Dunlap depends on INPUT=y 2939d8d01a63SDaniel Drake select POWER_SUPPLY 2940a7f7f624SMasahiro Yamada help 29417feda8e9SDaniel Drake Add support for SCI-based features of the OLPC XO-1 laptop: 29427bc74b3dSDaniel Drake - EC-driven system wakeups 29437feda8e9SDaniel Drake - Power button 29447bc74b3dSDaniel Drake - Ebook switch 29452cf2baeaSDaniel Drake - Lid switch 2946e1040ac6SDaniel Drake - AC adapter status updates 2947e1040ac6SDaniel Drake - Battery status updates 29487feda8e9SDaniel Drake 2949a0f30f59SDaniel Drakeconfig OLPC_XO15_SCI 2950a0f30f59SDaniel Drake bool "OLPC XO-1.5 SCI extras" 2951d8d01a63SDaniel Drake depends on OLPC && ACPI 2952d8d01a63SDaniel Drake select POWER_SUPPLY 2953a7f7f624SMasahiro Yamada help 2954a0f30f59SDaniel Drake Add support for SCI-based features of the OLPC XO-1.5 laptop: 2955a0f30f59SDaniel Drake - EC-driven system wakeups 2956a0f30f59SDaniel Drake - AC adapter status updates 2957a0f30f59SDaniel Drake - Battery status updates 2958e279b6c1SSam Ravnborg 2959d4f3e350SEd Wildgooseconfig ALIX 2960d4f3e350SEd Wildgoose bool "PCEngines ALIX System Support (LED setup)" 2961d4f3e350SEd Wildgoose select GPIOLIB 2962a7f7f624SMasahiro Yamada help 2963d4f3e350SEd Wildgoose This option enables system support for the PCEngines ALIX. 2964d4f3e350SEd Wildgoose At present this just sets up LEDs for GPIO control on 2965d4f3e350SEd Wildgoose ALIX2/3/6 boards. However, other system specific setup should 2966d4f3e350SEd Wildgoose get added here. 2967d4f3e350SEd Wildgoose 2968d4f3e350SEd Wildgoose Note: You must still enable the drivers for GPIO and LED support 2969d4f3e350SEd Wildgoose (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2970d4f3e350SEd Wildgoose 2971d4f3e350SEd Wildgoose Note: You have to set alix.force=1 for boards with Award BIOS. 2972d4f3e350SEd Wildgoose 2973da4e3302SPhilip Prindevilleconfig NET5501 2974da4e3302SPhilip Prindeville bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2975da4e3302SPhilip Prindeville select GPIOLIB 2976a7f7f624SMasahiro Yamada help 2977da4e3302SPhilip Prindeville This option enables system support for the Soekris Engineering net5501. 2978da4e3302SPhilip Prindeville 29793197059aSPhilip A. Prindevilleconfig GEOS 29803197059aSPhilip A. Prindeville bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 29813197059aSPhilip A. Prindeville select GPIOLIB 29823197059aSPhilip A. Prindeville depends on DMI 2983a7f7f624SMasahiro Yamada help 29843197059aSPhilip A. Prindeville This option enables system support for the Traverse Technologies GEOS. 29853197059aSPhilip A. Prindeville 29867d029125SVivien Didelotconfig TS5500 29877d029125SVivien Didelot bool "Technologic Systems TS-5500 platform support" 29887d029125SVivien Didelot depends on MELAN 29897d029125SVivien Didelot select CHECK_SIGNATURE 29907d029125SVivien Didelot select NEW_LEDS 29917d029125SVivien Didelot select LEDS_CLASS 2992a7f7f624SMasahiro Yamada help 29937d029125SVivien Didelot This option enables system support for the Technologic Systems TS-5500. 29947d029125SVivien Didelot 2995e279b6c1SSam Ravnborgendif # X86_32 2996e279b6c1SSam Ravnborg 299723ac4ae8SAndreas Herrmannconfig AMD_NB 2998e279b6c1SSam Ravnborg def_bool y 29990e152cd7SBorislav Petkov depends on CPU_SUP_AMD && PCI 3000e279b6c1SSam Ravnborg 3001e279b6c1SSam Ravnborgendmenu 3002e279b6c1SSam Ravnborg 30031572497cSChristoph Hellwigmenu "Binary Emulations" 3004e279b6c1SSam Ravnborg 3005e279b6c1SSam Ravnborgconfig IA32_EMULATION 3006e279b6c1SSam Ravnborg bool "IA32 Emulation" 3007e279b6c1SSam Ravnborg depends on X86_64 300839f88911SIngo Molnar select ARCH_WANT_OLD_COMPAT_IPC 3009d1603990SRandy Dunlap select BINFMT_ELF 301039f88911SIngo Molnar select COMPAT_OLD_SIGACTION 3011a7f7f624SMasahiro Yamada help 30125fd92e65SH. J. Lu Include code to run legacy 32-bit programs under a 30135fd92e65SH. J. Lu 64-bit kernel. You should likely turn this on, unless you're 30145fd92e65SH. J. Lu 100% sure that you don't have any 32-bit programs left. 3015e279b6c1SSam Ravnborg 3016a11e0975SNikolay Borisovconfig IA32_EMULATION_DEFAULT_DISABLED 3017a11e0975SNikolay Borisov bool "IA32 emulation disabled by default" 3018a11e0975SNikolay Borisov default n 3019a11e0975SNikolay Borisov depends on IA32_EMULATION 3020a11e0975SNikolay Borisov help 3021a11e0975SNikolay Borisov Make IA32 emulation disabled by default. This prevents loading 32-bit 3022a11e0975SNikolay Borisov processes and access to 32-bit syscalls. If unsure, leave it to its 3023a11e0975SNikolay Borisov default value. 3024a11e0975SNikolay Borisov 302583a44a4fSMasahiro Yamadaconfig X86_X32_ABI 30266ea30386SKees Cook bool "x32 ABI for 64-bit mode" 30279b54050bSBrian Gerst depends on X86_64 3028aaeed6ecSNathan Chancellor # llvm-objcopy does not convert x86_64 .note.gnu.property or 3029aaeed6ecSNathan Chancellor # compressed debug sections to x86_x32 properly: 3030aaeed6ecSNathan Chancellor # https://github.com/ClangBuiltLinux/linux/issues/514 3031aaeed6ecSNathan Chancellor # https://github.com/ClangBuiltLinux/linux/issues/1141 3032aaeed6ecSNathan Chancellor depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm) 3033a7f7f624SMasahiro Yamada help 30345fd92e65SH. J. Lu Include code to run binaries for the x32 native 32-bit ABI 30355fd92e65SH. J. Lu for 64-bit processors. An x32 process gets access to the 30365fd92e65SH. J. Lu full 64-bit register file and wide data path while leaving 30375fd92e65SH. J. Lu pointers at 32 bits for smaller memory footprint. 30385fd92e65SH. J. Lu 3039953fee1dSIngo Molnarconfig COMPAT_32 3040953fee1dSIngo Molnar def_bool y 3041953fee1dSIngo Molnar depends on IA32_EMULATION || X86_32 3042953fee1dSIngo Molnar select HAVE_UID16 3043953fee1dSIngo Molnar select OLD_SIGSUSPEND3 3044953fee1dSIngo Molnar 3045e279b6c1SSam Ravnborgconfig COMPAT 30463c2362e6SHarvey Harrison def_bool y 304783a44a4fSMasahiro Yamada depends on IA32_EMULATION || X86_X32_ABI 3048e279b6c1SSam Ravnborg 3049e279b6c1SSam Ravnborgconfig COMPAT_FOR_U64_ALIGNMENT 30503120e25eSJan Beulich def_bool y 3051a9251280SLinus Torvalds depends on COMPAT 3052ee009e4aSDavid Howells 3053e279b6c1SSam Ravnborgendmenu 3054e279b6c1SSam Ravnborg 3055e5beae16SKeith Packardconfig HAVE_ATOMIC_IOMAP 3056e5beae16SKeith Packard def_bool y 3057e5beae16SKeith Packard depends on X86_32 3058e5beae16SKeith Packard 3059edf88417SAvi Kivitysource "arch/x86/kvm/Kconfig" 30605e8ebd84SJason A. Donenfeld 30615e8ebd84SJason A. Donenfeldsource "arch/x86/Kconfig.assembler" 3062