1b2441318SGreg Kroah-Hartman# SPDX-License-Identifier: GPL-2.0 2daa93fabSSam Ravnborg# Select 32 or 64 bit 3daa93fabSSam Ravnborgconfig 64BIT 4104daea1SMasahiro Yamada bool "64-bit kernel" if "$(ARCH)" = "x86" 5104daea1SMasahiro Yamada default "$(ARCH)" != "i386" 6a7f7f624SMasahiro Yamada help 7daa93fabSSam Ravnborg Say yes to build a 64-bit kernel - formerly known as x86_64 8daa93fabSSam Ravnborg Say no to build a 32-bit kernel - formerly known as i386 9daa93fabSSam Ravnborg 10daa93fabSSam Ravnborgconfig X86_32 113120e25eSJan Beulich def_bool y 123120e25eSJan Beulich depends on !64BIT 13341c787eSIngo Molnar # Options that are inherently 32-bit kernel only: 14341c787eSIngo Molnar select ARCH_WANT_IPC_PARSE_VERSION 15341c787eSIngo Molnar select CLKSRC_I8253 16341c787eSIngo Molnar select CLONE_BACKWARDS 17157e118bSThomas Gleixner select GENERIC_VDSO_32 18117ed454SThomas Gleixner select HAVE_DEBUG_STACKOVERFLOW 19157e118bSThomas Gleixner select KMAP_LOCAL 20341c787eSIngo Molnar select MODULES_USE_ELF_REL 21341c787eSIngo Molnar select OLD_SIGACTION 222ca408d9SBrian Gerst select ARCH_SPLIT_ARG64 23daa93fabSSam Ravnborg 24daa93fabSSam Ravnborgconfig X86_64 253120e25eSJan Beulich def_bool y 263120e25eSJan Beulich depends on 64BIT 27d94e0685SIngo Molnar # Options that are inherently 64-bit kernel only: 284eb0716eSAlexandre Ghiti select ARCH_HAS_GIGANTIC_PAGE 29c12d3362SArd Biesheuvel select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 300bff0aaeSSuren Baghdasaryan select ARCH_SUPPORTS_PER_VMA_LOCK 31d94e0685SIngo Molnar select ARCH_USE_CMPXCHG_LOCKREF 32d94e0685SIngo Molnar select HAVE_ARCH_SOFT_DIRTY 33d94e0685SIngo Molnar select MODULES_USE_ELF_RELA 34f616ab59SChristoph Hellwig select NEED_DMA_MAP_STATE 3509230cbcSChristoph Hellwig select SWIOTLB 367facdc42SAl Viro select ARCH_HAS_ELFCORE_COMPAT 3763703f37SKefeng Wang select ZONE_DMA32 381032c0baSSam Ravnborg 39518049d9SSteven Rostedt (VMware)config FORCE_DYNAMIC_FTRACE 40518049d9SSteven Rostedt (VMware) def_bool y 41518049d9SSteven Rostedt (VMware) depends on X86_32 42518049d9SSteven Rostedt (VMware) depends on FUNCTION_TRACER 43518049d9SSteven Rostedt (VMware) select DYNAMIC_FTRACE 44518049d9SSteven Rostedt (VMware) help 45518049d9SSteven Rostedt (VMware) We keep the static function tracing (!DYNAMIC_FTRACE) around 46518049d9SSteven Rostedt (VMware) in order to test the non static function tracing in the 47518049d9SSteven Rostedt (VMware) generic code, as other architectures still use it. But we 48518049d9SSteven Rostedt (VMware) only need to keep it around for x86_64. No need to keep it 49518049d9SSteven Rostedt (VMware) for x86_32. For x86_32, force DYNAMIC_FTRACE. 50d94e0685SIngo Molnar# 51d94e0685SIngo Molnar# Arch settings 52d94e0685SIngo Molnar# 53d94e0685SIngo Molnar# ( Note that options that are marked 'if X86_64' could in principle be 54d94e0685SIngo Molnar# ported to 32-bit as well. ) 55d94e0685SIngo Molnar# 568d5fffb9SSam Ravnborgconfig X86 573c2362e6SHarvey Harrison def_bool y 58c763ea26SIngo Molnar # 59c763ea26SIngo Molnar # Note: keep this list sorted alphabetically 60c763ea26SIngo Molnar # 616471b825SIngo Molnar select ACPI_LEGACY_TABLES_LOOKUP if ACPI 626e0a0ea1SGraeme Gregory select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 63942fa985SYury Norov select ARCH_32BIT_OFF_T if X86_32 642a21ad57SThomas Gleixner select ARCH_CLOCKSOURCE_INIT 651f6d3a8fSMasami Hiramatsu select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 661e866974SAnshuman Khandual select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION 675c11f00bSDavid Hildenbrand select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64 6891024b3cSAnshuman Khandual select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG 69cebc774fSAnshuman Khandual select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE) 701e866974SAnshuman Khandual select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE 7191dda51aSAleksey Makarov select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 72c2280be8SAnshuman Khandual select ARCH_HAS_CACHE_LINE_SIZE 731156b441SDavidlohr Bueso select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION 747c7077a7SThomas Gleixner select ARCH_HAS_CPU_FINALIZE_INIT 752792d84eSKees Cook select ARCH_HAS_CURRENT_STACK_POINTER 76fa5b6ec9SLaura Abbott select ARCH_HAS_DEBUG_VIRTUAL 77399145f9SAnshuman Khandual select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 7821266be9SDan Williams select ARCH_HAS_DEVMEM_IS_ALLOWED 79b1a57bbfSDouglas Anderson select ARCH_HAS_EARLY_DEBUG if KGDB 806471b825SIngo Molnar select ARCH_HAS_ELF_RANDOMIZE 8172d93104SLinus Torvalds select ARCH_HAS_FAST_MULTIPLIER 826974f0c4SDaniel Micay select ARCH_HAS_FORTIFY_SOURCE 83957e3facSRiku Voipio select ARCH_HAS_GCOV_PROFILE_ALL 84bece04b5SMarco Elver select ARCH_HAS_KCOV if X86_64 850c9c1d56SThiago Jung Bauermann select ARCH_HAS_MEM_ENCRYPT 8610bcc80eSMathieu Desnoyers select ARCH_HAS_MEMBARRIER_SYNC_CORE 8749f88c70SPaul E. McKenney select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS 880ebeea8cSDaniel Borkmann select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 89c763ea26SIngo Molnar select ARCH_HAS_PMEM_API if X86_64 9017596731SRobin Murphy select ARCH_HAS_PTE_DEVMAP if X86_64 913010a5eaSLaurent Dufour select ARCH_HAS_PTE_SPECIAL 92eed9a328SYu Zhao select ARCH_HAS_NONLEAF_PMD_YOUNG if PGTABLE_LEVELS > 2 930aed55afSDan Williams select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 94ec6347bbSDan Williams select ARCH_HAS_COPY_MC if X86_64 95d2852a22SDaniel Borkmann select ARCH_HAS_SET_MEMORY 96d253ca0cSRick Edgecombe select ARCH_HAS_SET_DIRECT_MAP 97ad21fc4fSLaura Abbott select ARCH_HAS_STRICT_KERNEL_RWX 98ad21fc4fSLaura Abbott select ARCH_HAS_STRICT_MODULE_RWX 99ac1ab12aSMathieu Desnoyers select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 10025c619e5SBrian Gerst select ARCH_HAS_SYSCALL_WRAPPER 101c6d30853SAndrey Ryabinin select ARCH_HAS_UBSAN_SANITIZE_ALL 1027e01ccb4SZong Li select ARCH_HAS_DEBUG_WX 10363703f37SKefeng Wang select ARCH_HAS_ZONE_DMA_SET if EXPERT 1046471b825SIngo Molnar select ARCH_HAVE_NMI_SAFE_CMPXCHG 10504d5ea46SAneesh Kumar K.V select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 1066471b825SIngo Molnar select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 10777fbbc81SMark Salter select ARCH_MIGHT_HAVE_PC_PARPORT 1085e2c18c0SMark Salter select ARCH_MIGHT_HAVE_PC_SERIO 1093599fe12SThomas Gleixner select ARCH_STACKWALK 1102c870e61SArnd Bergmann select ARCH_SUPPORTS_ACPI 1116471b825SIngo Molnar select ARCH_SUPPORTS_ATOMIC_RMW 1125d6ad668SMike Rapoport select ARCH_SUPPORTS_DEBUG_PAGEALLOC 113d283d422SPasha Tatashin select ARCH_SUPPORTS_PAGE_TABLE_CHECK if X86_64 1146471b825SIngo Molnar select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 11514df3267SThomas Gleixner select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 1163c516f89SSami Tolvanen select ARCH_SUPPORTS_CFI_CLANG if X86_64 1173c516f89SSami Tolvanen select ARCH_USES_CFI_TRAPS if X86_64 && CFI_CLANG 118583bfd48SNathan Chancellor select ARCH_SUPPORTS_LTO_CLANG 119583bfd48SNathan Chancellor select ARCH_SUPPORTS_LTO_CLANG_THIN 1206471b825SIngo Molnar select ARCH_USE_BUILTIN_BSWAP 121dce44566SAnshuman Khandual select ARCH_USE_MEMTEST 1226471b825SIngo Molnar select ARCH_USE_QUEUED_RWLOCKS 1236471b825SIngo Molnar select ARCH_USE_QUEUED_SPINLOCKS 1242ce0d7f9SMark Brown select ARCH_USE_SYM_ANNOTATIONS 125ce4a4e56SAndy Lutomirski select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 12681c22041SDaniel Borkmann select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 127c763ea26SIngo Molnar select ARCH_WANTS_DYNAMIC_TASK_STRUCT 12851c2ee6dSNick Desaulniers select ARCH_WANTS_NO_INSTR 12907431506SAnshuman Khandual select ARCH_WANT_GENERAL_HUGETLB 1303876d4a3SAlexandre Ghiti select ARCH_WANT_HUGE_PMD_SHARE 13159612b24SNathan Chancellor select ARCH_WANT_LD_ORPHAN_WARN 1320b6f1582SAneesh Kumar K.V select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP if X86_64 1330b6f1582SAneesh Kumar K.V select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP if X86_64 13438d8b4e6SHuang Ying select ARCH_WANTS_THP_SWAP if X86_64 135b5f06f64SBalbir Singh select ARCH_HAS_PARANOID_L1D_FLUSH 13610916706SShile Zhang select BUILDTIME_TABLE_SORT 1376471b825SIngo Molnar select CLKEVT_I8253 1386471b825SIngo Molnar select CLOCKSOURCE_VALIDATE_LAST_CYCLE 1396471b825SIngo Molnar select CLOCKSOURCE_WATCHDOG 1407cf8f44aSAlexander Potapenko # Word-size accesses may read uninitialized data past the trailing \0 1417cf8f44aSAlexander Potapenko # in strings and cause false KMSAN reports. 1427cf8f44aSAlexander Potapenko select DCACHE_WORD_ACCESS if !KMSAN 1433aac3ebeSThomas Gleixner select DYNAMIC_SIGFRAME 14445471cd9SLinus Torvalds select EDAC_ATOMIC_SCRUB 14545471cd9SLinus Torvalds select EDAC_SUPPORT 1466471b825SIngo Molnar select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 1476471b825SIngo Molnar select GENERIC_CLOCKEVENTS_MIN_ADJUST 1486471b825SIngo Molnar select GENERIC_CMOS_UPDATE 1496471b825SIngo Molnar select GENERIC_CPU_AUTOPROBE 15061dc0f55SThomas Gleixner select GENERIC_CPU_VULNERABILITIES 1516471b825SIngo Molnar select GENERIC_EARLY_IOREMAP 15227d6b4d1SThomas Gleixner select GENERIC_ENTRY 1536471b825SIngo Molnar select GENERIC_IOMAP 154c7d6c9ddSThomas Gleixner select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 1550fa115daSThomas Gleixner select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 156ad7a929fSThomas Gleixner select GENERIC_IRQ_MIGRATION if SMP 1576471b825SIngo Molnar select GENERIC_IRQ_PROBE 158c201c917SThomas Gleixner select GENERIC_IRQ_RESERVATION_MODE 1596471b825SIngo Molnar select GENERIC_IRQ_SHOW 1606471b825SIngo Molnar select GENERIC_PENDING_IRQ if SMP 1612ae27137SSteven Price select GENERIC_PTDUMP 1626471b825SIngo Molnar select GENERIC_SMP_IDLE_THREAD 1636471b825SIngo Molnar select GENERIC_TIME_VSYSCALL 1647ac87074SVincenzo Frascino select GENERIC_GETTIMEOFDAY 165550a77a7SDmitry Safonov select GENERIC_VDSO_TIME_NS 1666ca297d4SPeter Zijlstra select GUP_GET_PXX_LOW_HIGH if X86_PAE 16717e5888eSHans de Goede select HARDIRQS_SW_RESEND 1687edaeb68SThomas Gleixner select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 169fcbfe812SNiklas Schnelle select HAS_IOPORT 1706471b825SIngo Molnar select HAVE_ACPI_APEI if ACPI 1716471b825SIngo Molnar select HAVE_ACPI_APEI_NMI if ACPI 1726471b825SIngo Molnar select HAVE_ALIGNED_STRUCT_PAGE if SLUB 1736471b825SIngo Molnar select HAVE_ARCH_AUDITSYSCALL 1746471b825SIngo Molnar select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 175eed1fceeSSong Liu select HAVE_ARCH_HUGE_VMALLOC if X86_64 1766471b825SIngo Molnar select HAVE_ARCH_JUMP_LABEL 177b34006c4SArd Biesheuvel select HAVE_ARCH_JUMP_LABEL_RELATIVE 178d17a1d97SAndrey Ryabinin select HAVE_ARCH_KASAN if X86_64 1790609ae01SDaniel Axtens select HAVE_ARCH_KASAN_VMALLOC if X86_64 1801dc0da6eSAlexander Potapenko select HAVE_ARCH_KFENCE 1814ca8cc8dSAlexander Potapenko select HAVE_ARCH_KMSAN if X86_64 1826471b825SIngo Molnar select HAVE_ARCH_KGDB 1839e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_BITS if MMU 1849e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 1851b028f78SDmitry Safonov select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 186271ca788SArd Biesheuvel select HAVE_ARCH_PREL32_RELOCATIONS 1876471b825SIngo Molnar select HAVE_ARCH_SECCOMP_FILTER 188f7d83c1cSKees Cook select HAVE_ARCH_THREAD_STRUCT_WHITELIST 189afaef01cSAlexander Popov select HAVE_ARCH_STACKLEAK 1906471b825SIngo Molnar select HAVE_ARCH_TRACEHOOK 1916471b825SIngo Molnar select HAVE_ARCH_TRANSPARENT_HUGEPAGE 192a00cc7d9SMatthew Wilcox select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 193b64d8d1eSPeter Xu select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 1947677f7fdSAxel Rasmussen select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 195e37e43a4SAndy Lutomirski select HAVE_ARCH_VMAP_STACK if X86_64 196fe950f60SKees Cook select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 197c763ea26SIngo Molnar select HAVE_ARCH_WITHIN_STACK_FRAMES 1982ff2b7ecSMasahiro Yamada select HAVE_ASM_MODVERSIONS 1996471b825SIngo Molnar select HAVE_CMPXCHG_DOUBLE 2006471b825SIngo Molnar select HAVE_CMPXCHG_LOCAL 20124a9c541SFrederic Weisbecker select HAVE_CONTEXT_TRACKING_USER if X86_64 20224a9c541SFrederic Weisbecker select HAVE_CONTEXT_TRACKING_USER_OFFSTACK if HAVE_CONTEXT_TRACKING_USER 2036471b825SIngo Molnar select HAVE_C_RECORDMCOUNT 20403f16cd0SJosh Poimboeuf select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL 205280981d6SSathvika Vasireddy select HAVE_OBJTOOL_NOP_MCOUNT if HAVE_OBJTOOL_MCOUNT 2064ed308c4SSteven Rostedt (Google) select HAVE_BUILDTIME_MCOUNT_SORT 2076471b825SIngo Molnar select HAVE_DEBUG_KMEMLEAK 2089c5a3621SAkinobu Mita select HAVE_DMA_CONTIGUOUS 209677aa9f7SSteven Rostedt select HAVE_DYNAMIC_FTRACE 21006aeaaeaSMasami Hiramatsu select HAVE_DYNAMIC_FTRACE_WITH_REGS 21102a474caSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 212562955feSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 213c316eb44SHeiko Carstens select HAVE_SAMPLE_FTRACE_DIRECT if X86_64 214503e4510SHeiko Carstens select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64 21503f5781bSWang YanQing select HAVE_EBPF_JIT 21658340a07SJohannes Berg select HAVE_EFFICIENT_UNALIGNED_ACCESS 2176630a8e5SChristoph Hellwig select HAVE_EISA 2185f56a5dfSJiri Slaby select HAVE_EXIT_THREAD 21967a929e0SChristoph Hellwig select HAVE_FAST_GUP 220644e0e8dSSteven Rostedt (VMware) select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 2216471b825SIngo Molnar select HAVE_FTRACE_MCOUNT_RECORD 222d938ba17SDonglin Peng select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER 2234a30e4c9SSteven Rostedt (VMware) select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) 2246471b825SIngo Molnar select HAVE_FUNCTION_TRACER 2256b90bd4bSEmese Revfy select HAVE_GCC_PLUGINS 2260067f129SK.Prasad select HAVE_HW_BREAKPOINT 2276471b825SIngo Molnar select HAVE_IOREMAP_PROT 228624db9eaSThomas Gleixner select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 2296471b825SIngo Molnar select HAVE_IRQ_TIME_ACCOUNTING 2304ab7674fSJosh Poimboeuf select HAVE_JUMP_LABEL_HACK if HAVE_OBJTOOL 2316471b825SIngo Molnar select HAVE_KERNEL_BZIP2 2326471b825SIngo Molnar select HAVE_KERNEL_GZIP 2336471b825SIngo Molnar select HAVE_KERNEL_LZ4 2346471b825SIngo Molnar select HAVE_KERNEL_LZMA 2356471b825SIngo Molnar select HAVE_KERNEL_LZO 2366471b825SIngo Molnar select HAVE_KERNEL_XZ 237fb46d057SNick Terrell select HAVE_KERNEL_ZSTD 2386471b825SIngo Molnar select HAVE_KPROBES 2396471b825SIngo Molnar select HAVE_KPROBES_ON_FTRACE 240540adea3SMasami Hiramatsu select HAVE_FUNCTION_ERROR_INJECTION 2416471b825SIngo Molnar select HAVE_KRETPROBES 242f3a112c0SMasami Hiramatsu select HAVE_RETHOOK 2436471b825SIngo Molnar select HAVE_KVM 2446471b825SIngo Molnar select HAVE_LIVEPATCH if X86_64 2450102752eSFrederic Weisbecker select HAVE_MIXED_BREAKPOINTS_REGS 246ee9f8fceSJosh Poimboeuf select HAVE_MOD_ARCH_SPECIFIC 2479f132f7eSJoel Fernandes (Google) select HAVE_MOVE_PMD 248be37c98dSKalesh Singh select HAVE_MOVE_PUD 24922102f45SJosh Poimboeuf select HAVE_NOINSTR_HACK if HAVE_OBJTOOL 25042a0bb3fSPetr Mladek select HAVE_NMI 251489e355bSJosh Poimboeuf select HAVE_NOINSTR_VALIDATION if HAVE_OBJTOOL 25203f16cd0SJosh Poimboeuf select HAVE_OBJTOOL if X86_64 2536471b825SIngo Molnar select HAVE_OPTPROBES 2546471b825SIngo Molnar select HAVE_PCSPKR_PLATFORM 2556471b825SIngo Molnar select HAVE_PERF_EVENTS 256c01d4323SFrederic Weisbecker select HAVE_PERF_EVENTS_NMI 25792e5aae4SNicholas Piggin select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 258eb01d42aSChristoph Hellwig select HAVE_PCI 259c5e63197SJiri Olsa select HAVE_PERF_REGS 260c5ebcedbSJiri Olsa select HAVE_PERF_USER_STACK_DUMP 261ff2e6d72SPeter Zijlstra select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 2621e9fdf21SPeter Zijlstra select MMU_GATHER_MERGE_VMAS 26300998085SThomas Gleixner select HAVE_POSIX_CPU_TIMERS_TASK_WORK 2646471b825SIngo Molnar select HAVE_REGS_AND_STACK_ACCESS_API 26503f16cd0SJosh Poimboeuf select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC || STACK_VALIDATION 2663c88ee19SMasami Hiramatsu select HAVE_FUNCTION_ARG_ACCESS_API 2677ecd19cfSKefeng Wang select HAVE_SETUP_PER_CPU_AREA 268cd1a41ceSThomas Gleixner select HAVE_SOFTIRQ_ON_OWN_STACK 269d148eac0SMasahiro Yamada select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 27003f16cd0SJosh Poimboeuf select HAVE_STACK_VALIDATION if HAVE_OBJTOOL 271e6d6c071SJosh Poimboeuf select HAVE_STATIC_CALL 27203f16cd0SJosh Poimboeuf select HAVE_STATIC_CALL_INLINE if HAVE_OBJTOOL 27399cf983cSMark Rutland select HAVE_PREEMPT_DYNAMIC_CALL 274d6761b8fSMathieu Desnoyers select HAVE_RSEQ 27509498135SMiguel Ojeda select HAVE_RUST if X86_64 2766471b825SIngo Molnar select HAVE_SYSCALL_TRACEPOINTS 2775f3da8c0SJosh Poimboeuf select HAVE_UACCESS_VALIDATION if HAVE_OBJTOOL 2786471b825SIngo Molnar select HAVE_UNSTABLE_SCHED_CLOCK 2797c68af6eSAvi Kivity select HAVE_USER_RETURN_NOTIFIER 2807ac87074SVincenzo Frascino select HAVE_GENERIC_VDSO 2810c7ffa32SThomas Gleixner select HOTPLUG_PARALLEL if SMP && X86_64 28205736e4aSThomas Gleixner select HOTPLUG_SMT if SMP 2830c7ffa32SThomas Gleixner select HOTPLUG_SPLIT_STARTUP if SMP && X86_32 284c0185808SThomas Gleixner select IRQ_FORCED_THREADING 285c2508ec5SLinus Torvalds select LOCK_MM_AND_FIND_VMA 2867ecd19cfSKefeng Wang select NEED_PER_CPU_EMBED_FIRST_CHUNK 2877ecd19cfSKefeng Wang select NEED_PER_CPU_PAGE_FIRST_CHUNK 28886596f0aSChristoph Hellwig select NEED_SG_DMA_LENGTH 2892eac9c2dSChristoph Hellwig select PCI_DOMAINS if PCI 290625210cfSSinan Kaya select PCI_LOCKLESS_CONFIG if PCI 2916471b825SIngo Molnar select PERF_EVENTS 2923195ef59SPrarit Bhargava select RTC_LIB 293d6faca40SArnd Bergmann select RTC_MC146818_LIB 2946471b825SIngo Molnar select SPARSE_IRQ 2956471b825SIngo Molnar select SYSCTL_EXCEPTION_TRACE 29615f4eae7SAndy Lutomirski select THREAD_INFO_IN_TASK 2974aae683fSMasahiro Yamada select TRACE_IRQFLAGS_SUPPORT 2984510bffbSMark Rutland select TRACE_IRQFLAGS_NMI_SUPPORT 2996471b825SIngo Molnar select USER_STACKTRACE_SUPPORT 3003b02a051SIngo Molnar select HAVE_ARCH_KCSAN if X86_64 3010c608dadSAubrey Li select PROC_PID_ARCH_STATUS if PROC_FS 30250468e43SJarkko Sakkinen select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX 303d49a0626SPeter Zijlstra select FUNCTION_ALIGNMENT_16B if X86_64 || X86_ALIGNMENT_16 304d49a0626SPeter Zijlstra select FUNCTION_ALIGNMENT_4B 3059e2b4be3SNayna Jain imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 306ceea991aSJiri Olsa select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 3077d8330a5SBalbir Singh 308ba7e4d13SIngo Molnarconfig INSTRUCTION_DECODER 3093120e25eSJan Beulich def_bool y 3103120e25eSJan Beulich depends on KPROBES || PERF_EVENTS || UPROBES 311ba7e4d13SIngo Molnar 31251b26adaSLinus Torvaldsconfig OUTPUT_FORMAT 31351b26adaSLinus Torvalds string 31451b26adaSLinus Torvalds default "elf32-i386" if X86_32 31551b26adaSLinus Torvalds default "elf64-x86-64" if X86_64 31651b26adaSLinus Torvalds 3178d5fffb9SSam Ravnborgconfig LOCKDEP_SUPPORT 3183c2362e6SHarvey Harrison def_bool y 3198d5fffb9SSam Ravnborg 3208d5fffb9SSam Ravnborgconfig STACKTRACE_SUPPORT 3213c2362e6SHarvey Harrison def_bool y 3228d5fffb9SSam Ravnborg 3238d5fffb9SSam Ravnborgconfig MMU 3243c2362e6SHarvey Harrison def_bool y 3258d5fffb9SSam Ravnborg 3269e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MIN 3279e08f57dSDaniel Cashman default 28 if 64BIT 3289e08f57dSDaniel Cashman default 8 3299e08f57dSDaniel Cashman 3309e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MAX 3319e08f57dSDaniel Cashman default 32 if 64BIT 3329e08f57dSDaniel Cashman default 16 3339e08f57dSDaniel Cashman 3349e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MIN 3359e08f57dSDaniel Cashman default 8 3369e08f57dSDaniel Cashman 3379e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MAX 3389e08f57dSDaniel Cashman default 16 3399e08f57dSDaniel Cashman 3408d5fffb9SSam Ravnborgconfig SBUS 3418d5fffb9SSam Ravnborg bool 3428d5fffb9SSam Ravnborg 3438d5fffb9SSam Ravnborgconfig GENERIC_ISA_DMA 3443120e25eSJan Beulich def_bool y 3453120e25eSJan Beulich depends on ISA_DMA_API 3468d5fffb9SSam Ravnborg 347d911c67eSAlexander Potapenkoconfig GENERIC_CSUM 348d911c67eSAlexander Potapenko bool 349d911c67eSAlexander Potapenko default y if KMSAN || KASAN 350d911c67eSAlexander Potapenko 3518d5fffb9SSam Ravnborgconfig GENERIC_BUG 3523c2362e6SHarvey Harrison def_bool y 3538d5fffb9SSam Ravnborg depends on BUG 354b93a531eSJan Beulich select GENERIC_BUG_RELATIVE_POINTERS if X86_64 355b93a531eSJan Beulich 356b93a531eSJan Beulichconfig GENERIC_BUG_RELATIVE_POINTERS 357b93a531eSJan Beulich bool 3588d5fffb9SSam Ravnborg 3598d5fffb9SSam Ravnborgconfig ARCH_MAY_HAVE_PC_FDC 3603120e25eSJan Beulich def_bool y 3613120e25eSJan Beulich depends on ISA_DMA_API 3628d5fffb9SSam Ravnborg 3631032c0baSSam Ravnborgconfig GENERIC_CALIBRATE_DELAY 3641032c0baSSam Ravnborg def_bool y 3651032c0baSSam Ravnborg 3669a0b8415Svenkatesh.pallipadi@intel.comconfig ARCH_HAS_CPU_RELAX 3679a0b8415Svenkatesh.pallipadi@intel.com def_bool y 3688d5fffb9SSam Ravnborg 369801e4062SJohannes Bergconfig ARCH_HIBERNATION_POSSIBLE 370801e4062SJohannes Berg def_bool y 371801e4062SJohannes Berg 372f4cb5700SJohannes Bergconfig ARCH_SUSPEND_POSSIBLE 373f4cb5700SJohannes Berg def_bool y 374f4cb5700SJohannes Berg 3758d5fffb9SSam Ravnborgconfig AUDIT_ARCH 376e0fd24a3SJan Beulich def_bool y if X86_64 3778d5fffb9SSam Ravnborg 378d6f2d75aSAndrey Ryabininconfig KASAN_SHADOW_OFFSET 379d6f2d75aSAndrey Ryabinin hex 380d6f2d75aSAndrey Ryabinin depends on KASAN 381d6f2d75aSAndrey Ryabinin default 0xdffffc0000000000 382d6f2d75aSAndrey Ryabinin 38369575d38SShane Wangconfig HAVE_INTEL_TXT 38469575d38SShane Wang def_bool y 3856ea30386SKees Cook depends on INTEL_IOMMU && ACPI 38669575d38SShane Wang 3876b0c3d44SSam Ravnborgconfig X86_32_SMP 3886b0c3d44SSam Ravnborg def_bool y 3896b0c3d44SSam Ravnborg depends on X86_32 && SMP 3906b0c3d44SSam Ravnborg 3916b0c3d44SSam Ravnborgconfig X86_64_SMP 3926b0c3d44SSam Ravnborg def_bool y 3936b0c3d44SSam Ravnborg depends on X86_64 && SMP 3946b0c3d44SSam Ravnborg 3952b144498SSrikar Dronamrajuconfig ARCH_SUPPORTS_UPROBES 3962b144498SSrikar Dronamraju def_bool y 3972b144498SSrikar Dronamraju 398d20642f0SRob Herringconfig FIX_EARLYCON_MEM 399d20642f0SRob Herring def_bool y 400d20642f0SRob Herring 40194d49eb3SKirill A. Shutemovconfig DYNAMIC_PHYSICAL_MASK 40294d49eb3SKirill A. Shutemov bool 40394d49eb3SKirill A. Shutemov 40498233368SKirill A. Shutemovconfig PGTABLE_LEVELS 40598233368SKirill A. Shutemov int 40677ef56e4SKirill A. Shutemov default 5 if X86_5LEVEL 40798233368SKirill A. Shutemov default 4 if X86_64 40898233368SKirill A. Shutemov default 3 if X86_PAE 40998233368SKirill A. Shutemov default 2 41098233368SKirill A. Shutemov 4112a61f474SMasahiro Yamadaconfig CC_HAS_SANE_STACKPROTECTOR 4122a61f474SMasahiro Yamada bool 4131b866781SNathan Chancellor default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT 4141b866781SNathan Chancellor default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) 4152a61f474SMasahiro Yamada help 4162a61f474SMasahiro Yamada We have to make sure stack protector is unconditionally disabled if 4173fb0fdb3SAndy Lutomirski the compiler produces broken code or if it does not let us control 4183fb0fdb3SAndy Lutomirski the segment on 32-bit kernels. 4192a61f474SMasahiro Yamada 420506f1d07SSam Ravnborgmenu "Processor type and features" 421506f1d07SSam Ravnborg 422506f1d07SSam Ravnborgconfig SMP 423506f1d07SSam Ravnborg bool "Symmetric multi-processing support" 424a7f7f624SMasahiro Yamada help 425506f1d07SSam Ravnborg This enables support for systems with more than one CPU. If you have 4264a474157SRobert Graffham a system with only one CPU, say N. If you have a system with more 4274a474157SRobert Graffham than one CPU, say Y. 428506f1d07SSam Ravnborg 4294a474157SRobert Graffham If you say N here, the kernel will run on uni- and multiprocessor 430506f1d07SSam Ravnborg machines, but will use only one CPU of a multiprocessor machine. If 431506f1d07SSam Ravnborg you say Y here, the kernel will run on many, but not all, 4324a474157SRobert Graffham uniprocessor machines. On a uniprocessor machine, the kernel 433506f1d07SSam Ravnborg will run faster if you say N here. 434506f1d07SSam Ravnborg 435506f1d07SSam Ravnborg Note that if you say Y here and choose architecture "586" or 436506f1d07SSam Ravnborg "Pentium" under "Processor family", the kernel will not work on 486 437506f1d07SSam Ravnborg architectures. Similarly, multiprocessor kernels for the "PPro" 438506f1d07SSam Ravnborg architecture may not work on all Pentium based boards. 439506f1d07SSam Ravnborg 440506f1d07SSam Ravnborg People using multiprocessor machines who say Y here should also say 441506f1d07SSam Ravnborg Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 442506f1d07SSam Ravnborg Management" code will be disabled if you say Y here. 443506f1d07SSam Ravnborg 444ff61f079SJonathan Corbet See also <file:Documentation/arch/x86/i386/IO-APIC.rst>, 4454f4cfa6cSMauro Carvalho Chehab <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 446506f1d07SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 447506f1d07SSam Ravnborg 448506f1d07SSam Ravnborg If you don't know what to do here, say N. 449506f1d07SSam Ravnborg 45006cd9a7dSYinghai Luconfig X86_X2APIC 45106cd9a7dSYinghai Lu bool "Support x2apic" 45219e3d60dSJan Kiszka depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 453a7f7f624SMasahiro Yamada help 45406cd9a7dSYinghai Lu This enables x2apic support on CPUs that have this feature. 45506cd9a7dSYinghai Lu 45606cd9a7dSYinghai Lu This allows 32-bit apic IDs (so it can support very large systems), 45706cd9a7dSYinghai Lu and accesses the local apic via MSRs not via mmio. 45806cd9a7dSYinghai Lu 459b8d1d163SDaniel Sneddon Some Intel systems circa 2022 and later are locked into x2APIC mode 460b8d1d163SDaniel Sneddon and can not fall back to the legacy APIC modes if SGX or TDX are 461e3998434SMateusz Jończyk enabled in the BIOS. They will boot with very reduced functionality 462e3998434SMateusz Jończyk without enabling this option. 463b8d1d163SDaniel Sneddon 46406cd9a7dSYinghai Lu If you don't know what to do here, say N. 46506cd9a7dSYinghai Lu 4666695c85bSYinghai Luconfig X86_MPPARSE 4674590d98fSAndy Shevchenko bool "Enable MPS table" if ACPI 4687a527688SJan Beulich default y 4695ab74722SIngo Molnar depends on X86_LOCAL_APIC 470a7f7f624SMasahiro Yamada help 4716695c85bSYinghai Lu For old smp systems that do not have proper acpi support. Newer systems 4726695c85bSYinghai Lu (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 4736695c85bSYinghai Lu 474ddd70cf9SJun Nakajimaconfig GOLDFISH 475ddd70cf9SJun Nakajima def_bool y 476ddd70cf9SJun Nakajima depends on X86_GOLDFISH 477ddd70cf9SJun Nakajima 478e6d42931SJohannes Weinerconfig X86_CPU_RESCTRL 479e6d42931SJohannes Weiner bool "x86 CPU resource control support" 4806fe07ce3SBabu Moger depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 48159fe5a77SThomas Gleixner select KERNFS 482e79f15a4SChen Yu select PROC_CPU_RESCTRL if PROC_FS 48378e99b4aSFenghua Yu help 484e6d42931SJohannes Weiner Enable x86 CPU resource control support. 4856fe07ce3SBabu Moger 4866fe07ce3SBabu Moger Provide support for the allocation and monitoring of system resources 4876fe07ce3SBabu Moger usage by the CPU. 4886fe07ce3SBabu Moger 4896fe07ce3SBabu Moger Intel calls this Intel Resource Director Technology 4906fe07ce3SBabu Moger (Intel(R) RDT). More information about RDT can be found in the 4916fe07ce3SBabu Moger Intel x86 Architecture Software Developer Manual. 4926fe07ce3SBabu Moger 4936fe07ce3SBabu Moger AMD calls this AMD Platform Quality of Service (AMD QoS). 4946fe07ce3SBabu Moger More information about AMD QoS can be found in the AMD64 Technology 4956fe07ce3SBabu Moger Platform Quality of Service Extensions manual. 49678e99b4aSFenghua Yu 49778e99b4aSFenghua Yu Say N if unsure. 49878e99b4aSFenghua Yu 4998425091fSRavikiran G Thirumalaiif X86_32 500a0d0bb4dSRandy Dunlapconfig X86_BIGSMP 501a0d0bb4dSRandy Dunlap bool "Support for big SMP systems with more than 8 CPUs" 502a0d0bb4dSRandy Dunlap depends on SMP 503a7f7f624SMasahiro Yamada help 504e133f6eaSRandy Dunlap This option is needed for the systems that have more than 8 CPUs. 505a0d0bb4dSRandy Dunlap 506c5c606d9SRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 507c5c606d9SRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 508c5c606d9SRavikiran G Thirumalai default y 509a7f7f624SMasahiro Yamada help 51006ac8346SIngo Molnar If you disable this option then the kernel will only support 51106ac8346SIngo Molnar standard PC platforms. (which covers the vast majority of 51206ac8346SIngo Molnar systems out there.) 51306ac8346SIngo Molnar 5148425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5158425091fSRavikiran G Thirumalai for the following (non-PC) 32 bit x86 platforms: 516cb7b8023SBen Hutchings Goldfish (Android emulator) 5178425091fSRavikiran G Thirumalai AMD Elan 5188425091fSRavikiran G Thirumalai RDC R-321x SoC 5198425091fSRavikiran G Thirumalai SGI 320/540 (Visual Workstation) 52083125a3aSAlessandro Rubini STA2X11-based (e.g. Northville) 5213f4110a4SThomas Gleixner Moorestown MID devices 52206ac8346SIngo Molnar 52306ac8346SIngo Molnar If you have one of these systems, or if you want to build a 52406ac8346SIngo Molnar generic distribution kernel, say Y here - otherwise say N. 525758cd94aSJuerg Haefligerendif # X86_32 52606ac8346SIngo Molnar 5278425091fSRavikiran G Thirumalaiif X86_64 5288425091fSRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 5298425091fSRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 5308425091fSRavikiran G Thirumalai default y 531a7f7f624SMasahiro Yamada help 5328425091fSRavikiran G Thirumalai If you disable this option then the kernel will only support 5338425091fSRavikiran G Thirumalai standard PC platforms. (which covers the vast majority of 5348425091fSRavikiran G Thirumalai systems out there.) 5358425091fSRavikiran G Thirumalai 5368425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5378425091fSRavikiran G Thirumalai for the following (non-PC) 64 bit x86 platforms: 53844b111b5SSteffen Persvold Numascale NumaChip 5398425091fSRavikiran G Thirumalai ScaleMP vSMP 5408425091fSRavikiran G Thirumalai SGI Ultraviolet 5418425091fSRavikiran G Thirumalai 5428425091fSRavikiran G Thirumalai If you have one of these systems, or if you want to build a 5438425091fSRavikiran G Thirumalai generic distribution kernel, say Y here - otherwise say N. 544758cd94aSJuerg Haefligerendif # X86_64 545c5c606d9SRavikiran G Thirumalai# This is an alphabetically sorted list of 64 bit extended platforms 546c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 54744b111b5SSteffen Persvoldconfig X86_NUMACHIP 54844b111b5SSteffen Persvold bool "Numascale NumaChip" 54944b111b5SSteffen Persvold depends on X86_64 55044b111b5SSteffen Persvold depends on X86_EXTENDED_PLATFORM 55144b111b5SSteffen Persvold depends on NUMA 55244b111b5SSteffen Persvold depends on SMP 55344b111b5SSteffen Persvold depends on X86_X2APIC 554f9726bfdSDaniel J Blueman depends on PCI_MMCONFIG 555a7f7f624SMasahiro Yamada help 55644b111b5SSteffen Persvold Adds support for Numascale NumaChip large-SMP systems. Needed to 55744b111b5SSteffen Persvold enable more than ~168 cores. 55844b111b5SSteffen Persvold If you don't have one of these, you should say N here. 55903b48632SNick Piggin 5606a48565eSIngo Molnarconfig X86_VSMP 561c5c606d9SRavikiran G Thirumalai bool "ScaleMP vSMP" 5626276a074SBorislav Petkov select HYPERVISOR_GUEST 5636a48565eSIngo Molnar select PARAVIRT 5646a48565eSIngo Molnar depends on X86_64 && PCI 565c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 566ead91d4bSShai Fultheim depends on SMP 567a7f7f624SMasahiro Yamada help 5686a48565eSIngo Molnar Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 5696a48565eSIngo Molnar supposed to run on these EM64T-based machines. Only choose this option 5706a48565eSIngo Molnar if you have one of these machines. 5716a48565eSIngo Molnar 572c5c606d9SRavikiran G Thirumalaiconfig X86_UV 573c5c606d9SRavikiran G Thirumalai bool "SGI Ultraviolet" 574c5c606d9SRavikiran G Thirumalai depends on X86_64 575c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 57654c28d29SJack Steiner depends on NUMA 5771ecb4ae5SAndrew Morton depends on EFI 578c2209ea5SIngo Molnar depends on KEXEC_CORE 5799d6c26e7SSuresh Siddha depends on X86_X2APIC 5801222e564SIngo Molnar depends on PCI 581a7f7f624SMasahiro Yamada help 582c5c606d9SRavikiran G Thirumalai This option is needed in order to support SGI Ultraviolet systems. 583c5c606d9SRavikiran G Thirumalai If you don't have one of these, you should say N here. 584c5c606d9SRavikiran G Thirumalai 585c5c606d9SRavikiran G Thirumalai# Following is an alphabetically sorted list of 32 bit extended platforms 586c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 587506f1d07SSam Ravnborg 588ddd70cf9SJun Nakajimaconfig X86_GOLDFISH 589ddd70cf9SJun Nakajima bool "Goldfish (Virtual Platform)" 590cb7b8023SBen Hutchings depends on X86_EXTENDED_PLATFORM 591a7f7f624SMasahiro Yamada help 592ddd70cf9SJun Nakajima Enable support for the Goldfish virtual platform used primarily 593ddd70cf9SJun Nakajima for Android development. Unless you are building for the Android 594ddd70cf9SJun Nakajima Goldfish emulator say N here. 595ddd70cf9SJun Nakajima 596c751e17bSThomas Gleixnerconfig X86_INTEL_CE 597c751e17bSThomas Gleixner bool "CE4100 TV platform" 598c751e17bSThomas Gleixner depends on PCI 599c751e17bSThomas Gleixner depends on PCI_GODIRECT 6006084a6e2SJiang Liu depends on X86_IO_APIC 601c751e17bSThomas Gleixner depends on X86_32 602c751e17bSThomas Gleixner depends on X86_EXTENDED_PLATFORM 60337bc9f50SDirk Brandewie select X86_REBOOTFIXUPS 604da6b737bSSebastian Andrzej Siewior select OF 605da6b737bSSebastian Andrzej Siewior select OF_EARLY_FLATTREE 606a7f7f624SMasahiro Yamada help 607c751e17bSThomas Gleixner Select for the Intel CE media processor (CE4100) SOC. 608c751e17bSThomas Gleixner This option compiles in support for the CE4100 SOC for settop 609c751e17bSThomas Gleixner boxes and media devices. 610c751e17bSThomas Gleixner 6114cb9b00fSDavid Cohenconfig X86_INTEL_MID 61243605ef1SAlan Cox bool "Intel MID platform support" 61343605ef1SAlan Cox depends on X86_EXTENDED_PLATFORM 614edc6bc78SDavid Cohen depends on X86_PLATFORM_DEVICES 6151ea7c673SAlan Cox depends on PCI 6163fda5bb4SAndy Shevchenko depends on X86_64 || (PCI_GOANY && X86_32) 6171ea7c673SAlan Cox depends on X86_IO_APIC 6184cb9b00fSDavid Cohen select I2C 6197c9c3a1eSAlan Cox select DW_APB_TIMER 62054b34aa0SMika Westerberg select INTEL_SCU_PCI 621a7f7f624SMasahiro Yamada help 6224cb9b00fSDavid Cohen Select to build a kernel capable of supporting Intel MID (Mobile 6234cb9b00fSDavid Cohen Internet Device) platform systems which do not have the PCI legacy 6244cb9b00fSDavid Cohen interfaces. If you are building for a PC class system say N here. 6251ea7c673SAlan Cox 6264cb9b00fSDavid Cohen Intel MID platforms are based on an Intel processor and chipset which 6274cb9b00fSDavid Cohen consume less power than most of the x86 derivatives. 62843605ef1SAlan Cox 6298bbc2a13SBryan O'Donoghueconfig X86_INTEL_QUARK 6308bbc2a13SBryan O'Donoghue bool "Intel Quark platform support" 6318bbc2a13SBryan O'Donoghue depends on X86_32 6328bbc2a13SBryan O'Donoghue depends on X86_EXTENDED_PLATFORM 6338bbc2a13SBryan O'Donoghue depends on X86_PLATFORM_DEVICES 6348bbc2a13SBryan O'Donoghue depends on X86_TSC 6358bbc2a13SBryan O'Donoghue depends on PCI 6368bbc2a13SBryan O'Donoghue depends on PCI_GOANY 6378bbc2a13SBryan O'Donoghue depends on X86_IO_APIC 6388bbc2a13SBryan O'Donoghue select IOSF_MBI 6398bbc2a13SBryan O'Donoghue select INTEL_IMR 6409ab6eb51SAndy Shevchenko select COMMON_CLK 641a7f7f624SMasahiro Yamada help 6428bbc2a13SBryan O'Donoghue Select to include support for Quark X1000 SoC. 6438bbc2a13SBryan O'Donoghue Say Y here if you have a Quark based system such as the Arduino 6448bbc2a13SBryan O'Donoghue compatible Intel Galileo. 6458bbc2a13SBryan O'Donoghue 6463d48aab1SMika Westerbergconfig X86_INTEL_LPSS 6473d48aab1SMika Westerberg bool "Intel Low Power Subsystem Support" 6485962dd22SSinan Kaya depends on X86 && ACPI && PCI 6493d48aab1SMika Westerberg select COMMON_CLK 6500f531431SMathias Nyman select PINCTRL 651eebb3e8dSAndy Shevchenko select IOSF_MBI 652a7f7f624SMasahiro Yamada help 6533d48aab1SMika Westerberg Select to build support for Intel Low Power Subsystem such as 6543d48aab1SMika Westerberg found on Intel Lynxpoint PCH. Selecting this option enables 6550f531431SMathias Nyman things like clock tree (common clock framework) and pincontrol 6560f531431SMathias Nyman which are needed by the LPSS peripheral drivers. 6573d48aab1SMika Westerberg 65892082a88SKen Xueconfig X86_AMD_PLATFORM_DEVICE 65992082a88SKen Xue bool "AMD ACPI2Platform devices support" 66092082a88SKen Xue depends on ACPI 66192082a88SKen Xue select COMMON_CLK 66292082a88SKen Xue select PINCTRL 663a7f7f624SMasahiro Yamada help 66492082a88SKen Xue Select to interpret AMD specific ACPI device to platform device 66592082a88SKen Xue such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 66692082a88SKen Xue I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 66792082a88SKen Xue implemented under PINCTRL subsystem. 66892082a88SKen Xue 669ced3ce76SDavid E. Boxconfig IOSF_MBI 670ced3ce76SDavid E. Box tristate "Intel SoC IOSF Sideband support for SoC platforms" 671ced3ce76SDavid E. Box depends on PCI 672a7f7f624SMasahiro Yamada help 673ced3ce76SDavid E. Box This option enables sideband register access support for Intel SoC 674ced3ce76SDavid E. Box platforms. On these platforms the IOSF sideband is used in lieu of 675ced3ce76SDavid E. Box MSR's for some register accesses, mostly but not limited to thermal 676ced3ce76SDavid E. Box and power. Drivers may query the availability of this device to 677ced3ce76SDavid E. Box determine if they need the sideband in order to work on these 678ced3ce76SDavid E. Box platforms. The sideband is available on the following SoC products. 679ced3ce76SDavid E. Box This list is not meant to be exclusive. 680ced3ce76SDavid E. Box - BayTrail 681ced3ce76SDavid E. Box - Braswell 682ced3ce76SDavid E. Box - Quark 683ced3ce76SDavid E. Box 684ced3ce76SDavid E. Box You should say Y if you are running a kernel on one of these SoC's. 685ced3ce76SDavid E. Box 686ed2226bdSDavid E. Boxconfig IOSF_MBI_DEBUG 687ed2226bdSDavid E. Box bool "Enable IOSF sideband access through debugfs" 688ed2226bdSDavid E. Box depends on IOSF_MBI && DEBUG_FS 689a7f7f624SMasahiro Yamada help 690ed2226bdSDavid E. Box Select this option to expose the IOSF sideband access registers (MCR, 691ed2226bdSDavid E. Box MDR, MCRX) through debugfs to write and read register information from 692ed2226bdSDavid E. Box different units on the SoC. This is most useful for obtaining device 693ed2226bdSDavid E. Box state information for debug and analysis. As this is a general access 694ed2226bdSDavid E. Box mechanism, users of this option would have specific knowledge of the 695ed2226bdSDavid E. Box device they want to access. 696ed2226bdSDavid E. Box 697ed2226bdSDavid E. Box If you don't require the option or are in doubt, say N. 698ed2226bdSDavid E. Box 699c5c606d9SRavikiran G Thirumalaiconfig X86_RDC321X 700c5c606d9SRavikiran G Thirumalai bool "RDC R-321x SoC" 701506f1d07SSam Ravnborg depends on X86_32 702c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 703c5c606d9SRavikiran G Thirumalai select M486 704c5c606d9SRavikiran G Thirumalai select X86_REBOOTFIXUPS 705a7f7f624SMasahiro Yamada help 706c5c606d9SRavikiran G Thirumalai This option is needed for RDC R-321x system-on-chip, also known 707c5c606d9SRavikiran G Thirumalai as R-8610-(G). 708c5c606d9SRavikiran G Thirumalai If you don't have one of these chips, you should say N here. 709c5c606d9SRavikiran G Thirumalai 710e0c7ae37SIngo Molnarconfig X86_32_NON_STANDARD 7119c398017SIngo Molnar bool "Support non-standard 32-bit SMP architectures" 7129c398017SIngo Molnar depends on X86_32 && SMP 713c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 714a7f7f624SMasahiro Yamada help 715b5660ba7SH. Peter Anvin This option compiles in the bigsmp and STA2X11 default 716b5660ba7SH. Peter Anvin subarchitectures. It is intended for a generic binary 717b5660ba7SH. Peter Anvin kernel. If you select them all, kernel will probe it one by 718b5660ba7SH. Peter Anvin one and will fallback to default. 719d49c4288SYinghai Lu 720c5c606d9SRavikiran G Thirumalai# Alphabetically sorted list of Non standard 32 bit platforms 721d49c4288SYinghai Lu 722d949f36fSLinus Torvaldsconfig X86_SUPPORTS_MEMORY_FAILURE 7236fc108a0SJan Beulich def_bool y 724d949f36fSLinus Torvalds # MCE code calls memory_failure(): 725d949f36fSLinus Torvalds depends on X86_MCE 726d949f36fSLinus Torvalds # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 727d949f36fSLinus Torvalds # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 728d949f36fSLinus Torvalds depends on X86_64 || !SPARSEMEM 729d949f36fSLinus Torvalds select ARCH_SUPPORTS_MEMORY_FAILURE 730d949f36fSLinus Torvalds 73183125a3aSAlessandro Rubiniconfig STA2X11 73283125a3aSAlessandro Rubini bool "STA2X11 Companion Chip Support" 73383125a3aSAlessandro Rubini depends on X86_32_NON_STANDARD && PCI 73483125a3aSAlessandro Rubini select SWIOTLB 73583125a3aSAlessandro Rubini select MFD_STA2X11 7360145071bSLinus Walleij select GPIOLIB 737a7f7f624SMasahiro Yamada help 73883125a3aSAlessandro Rubini This adds support for boards based on the STA2X11 IO-Hub, 73983125a3aSAlessandro Rubini a.k.a. "ConneXt". The chip is used in place of the standard 74083125a3aSAlessandro Rubini PC chipset, so all "standard" peripherals are missing. If this 74183125a3aSAlessandro Rubini option is selected the kernel will still be able to boot on 74283125a3aSAlessandro Rubini standard PC machines. 74383125a3aSAlessandro Rubini 74482148d1dSShérabconfig X86_32_IRIS 74582148d1dSShérab tristate "Eurobraille/Iris poweroff module" 74682148d1dSShérab depends on X86_32 747a7f7f624SMasahiro Yamada help 74882148d1dSShérab The Iris machines from EuroBraille do not have APM or ACPI support 74982148d1dSShérab to shut themselves down properly. A special I/O sequence is 75082148d1dSShérab needed to do so, which is what this module does at 75182148d1dSShérab kernel shutdown. 75282148d1dSShérab 75382148d1dSShérab This is only for Iris machines from EuroBraille. 75482148d1dSShérab 75582148d1dSShérab If unused, say N. 75682148d1dSShérab 757ae1e9130SIngo Molnarconfig SCHED_OMIT_FRAME_POINTER 7583c2362e6SHarvey Harrison def_bool y 7593c2362e6SHarvey Harrison prompt "Single-depth WCHAN output" 760a87d0914SKen Chen depends on X86 761a7f7f624SMasahiro Yamada help 762506f1d07SSam Ravnborg Calculate simpler /proc/<PID>/wchan values. If this option 763506f1d07SSam Ravnborg is disabled then wchan values will recurse back to the 764506f1d07SSam Ravnborg caller function. This provides more accurate wchan values, 765506f1d07SSam Ravnborg at the expense of slightly more scheduling overhead. 766506f1d07SSam Ravnborg 767506f1d07SSam Ravnborg If in doubt, say "Y". 768506f1d07SSam Ravnborg 7696276a074SBorislav Petkovmenuconfig HYPERVISOR_GUEST 7706276a074SBorislav Petkov bool "Linux guest support" 771a7f7f624SMasahiro Yamada help 7726276a074SBorislav Petkov Say Y here to enable options for running Linux under various hyper- 7736276a074SBorislav Petkov visors. This option enables basic hypervisor detection and platform 7746276a074SBorislav Petkov setup. 775506f1d07SSam Ravnborg 7766276a074SBorislav Petkov If you say N, all options in this submenu will be skipped and 7776276a074SBorislav Petkov disabled, and Linux guest support won't be built in. 778506f1d07SSam Ravnborg 7796276a074SBorislav Petkovif HYPERVISOR_GUEST 780506f1d07SSam Ravnborg 781e61bd94aSEduardo Pereira Habkostconfig PARAVIRT 782e61bd94aSEduardo Pereira Habkost bool "Enable paravirtualization code" 783a0e2bf7cSJuergen Gross depends on HAVE_STATIC_CALL 784a7f7f624SMasahiro Yamada help 785e61bd94aSEduardo Pereira Habkost This changes the kernel so it can modify itself when it is run 786e61bd94aSEduardo Pereira Habkost under a hypervisor, potentially improving performance significantly 787e61bd94aSEduardo Pereira Habkost over full virtualization. However, when run without a hypervisor 788e61bd94aSEduardo Pereira Habkost the kernel is theoretically slower and slightly larger. 789e61bd94aSEduardo Pereira Habkost 790c00a280aSJuergen Grossconfig PARAVIRT_XXL 791c00a280aSJuergen Gross bool 792c00a280aSJuergen Gross 7936276a074SBorislav Petkovconfig PARAVIRT_DEBUG 7946276a074SBorislav Petkov bool "paravirt-ops debugging" 7956276a074SBorislav Petkov depends on PARAVIRT && DEBUG_KERNEL 796a7f7f624SMasahiro Yamada help 7976276a074SBorislav Petkov Enable to debug paravirt_ops internals. Specifically, BUG if 7986276a074SBorislav Petkov a paravirt_op is missing when it is called. 7996276a074SBorislav Petkov 800b4ecc126SJeremy Fitzhardingeconfig PARAVIRT_SPINLOCKS 801b4ecc126SJeremy Fitzhardinge bool "Paravirtualization layer for spinlocks" 8026ea30386SKees Cook depends on PARAVIRT && SMP 803a7f7f624SMasahiro Yamada help 804b4ecc126SJeremy Fitzhardinge Paravirtualized spinlocks allow a pvops backend to replace the 805b4ecc126SJeremy Fitzhardinge spinlock implementation with something virtualization-friendly 806b4ecc126SJeremy Fitzhardinge (for example, block the virtual CPU rather than spinning). 807b4ecc126SJeremy Fitzhardinge 8084c4e4f61SRaghavendra K T It has a minimal impact on native kernels and gives a nice performance 8094c4e4f61SRaghavendra K T benefit on paravirtualized KVM / Xen kernels. 810b4ecc126SJeremy Fitzhardinge 8114c4e4f61SRaghavendra K T If you are unsure how to answer this question, answer Y. 812b4ecc126SJeremy Fitzhardinge 813ecca2502SZhao Yakuiconfig X86_HV_CALLBACK_VECTOR 814ecca2502SZhao Yakui def_bool n 815ecca2502SZhao Yakui 8166276a074SBorislav Petkovsource "arch/x86/xen/Kconfig" 8176276a074SBorislav Petkov 8186276a074SBorislav Petkovconfig KVM_GUEST 8196276a074SBorislav Petkov bool "KVM Guest support (including kvmclock)" 8206276a074SBorislav Petkov depends on PARAVIRT 8216276a074SBorislav Petkov select PARAVIRT_CLOCK 822a1c4423bSMarcelo Tosatti select ARCH_CPUIDLE_HALTPOLL 823b1d40575SVitaly Kuznetsov select X86_HV_CALLBACK_VECTOR 8246276a074SBorislav Petkov default y 825a7f7f624SMasahiro Yamada help 8266276a074SBorislav Petkov This option enables various optimizations for running under the KVM 8276276a074SBorislav Petkov hypervisor. It includes a paravirtualized clock, so that instead 8286276a074SBorislav Petkov of relying on a PIT (or probably other) emulation by the 8296276a074SBorislav Petkov underlying device model, the host provides the guest with 8306276a074SBorislav Petkov timing infrastructure such as time of day, and system time 8316276a074SBorislav Petkov 832a1c4423bSMarcelo Tosatticonfig ARCH_CPUIDLE_HALTPOLL 833a1c4423bSMarcelo Tosatti def_bool n 834a1c4423bSMarcelo Tosatti prompt "Disable host haltpoll when loading haltpoll driver" 835a1c4423bSMarcelo Tosatti help 836a1c4423bSMarcelo Tosatti If virtualized under KVM, disable host haltpoll. 837a1c4423bSMarcelo Tosatti 8387733607fSMaran Wilsonconfig PVH 8397733607fSMaran Wilson bool "Support for running PVH guests" 840a7f7f624SMasahiro Yamada help 8417733607fSMaran Wilson This option enables the PVH entry point for guest virtual machines 8427733607fSMaran Wilson as specified in the x86/HVM direct boot ABI. 8437733607fSMaran Wilson 8446276a074SBorislav Petkovconfig PARAVIRT_TIME_ACCOUNTING 8456276a074SBorislav Petkov bool "Paravirtual steal time accounting" 8466276a074SBorislav Petkov depends on PARAVIRT 847a7f7f624SMasahiro Yamada help 8486276a074SBorislav Petkov Select this option to enable fine granularity task steal time 8496276a074SBorislav Petkov accounting. Time spent executing other tasks in parallel with 8506276a074SBorislav Petkov the current vCPU is discounted from the vCPU power. To account for 8516276a074SBorislav Petkov that, there can be a small performance impact. 8526276a074SBorislav Petkov 8536276a074SBorislav Petkov If in doubt, say N here. 8546276a074SBorislav Petkov 8557af192c9SGerd Hoffmannconfig PARAVIRT_CLOCK 8567af192c9SGerd Hoffmann bool 8577af192c9SGerd Hoffmann 8584a362601SJan Kiszkaconfig JAILHOUSE_GUEST 8594a362601SJan Kiszka bool "Jailhouse non-root cell support" 860abde587bSArnd Bergmann depends on X86_64 && PCI 86187e65d05SJan Kiszka select X86_PM_TIMER 862a7f7f624SMasahiro Yamada help 8634a362601SJan Kiszka This option allows to run Linux as guest in a Jailhouse non-root 8644a362601SJan Kiszka cell. You can leave this option disabled if you only want to start 8654a362601SJan Kiszka Jailhouse and run Linux afterwards in the root cell. 8664a362601SJan Kiszka 867ec7972c9SZhao Yakuiconfig ACRN_GUEST 868ec7972c9SZhao Yakui bool "ACRN Guest support" 869ec7972c9SZhao Yakui depends on X86_64 870498ad393SZhao Yakui select X86_HV_CALLBACK_VECTOR 871ec7972c9SZhao Yakui help 872ec7972c9SZhao Yakui This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 873ec7972c9SZhao Yakui a flexible, lightweight reference open-source hypervisor, built with 874ec7972c9SZhao Yakui real-time and safety-criticality in mind. It is built for embedded 875ec7972c9SZhao Yakui IOT with small footprint and real-time features. More details can be 876ec7972c9SZhao Yakui found in https://projectacrn.org/. 877ec7972c9SZhao Yakui 87859bd54a8SKuppuswamy Sathyanarayananconfig INTEL_TDX_GUEST 87959bd54a8SKuppuswamy Sathyanarayanan bool "Intel TDX (Trust Domain Extensions) - Guest Support" 88059bd54a8SKuppuswamy Sathyanarayanan depends on X86_64 && CPU_SUP_INTEL 88159bd54a8SKuppuswamy Sathyanarayanan depends on X86_X2APIC 88275d090fdSKirill A. Shutemov depends on EFI_STUB 88341394e33SKirill A. Shutemov select ARCH_HAS_CC_PLATFORM 884968b4931SKirill A. Shutemov select X86_MEM_ENCRYPT 88577a512e3SSean Christopherson select X86_MCE 88675d090fdSKirill A. Shutemov select UNACCEPTED_MEMORY 88759bd54a8SKuppuswamy Sathyanarayanan help 88859bd54a8SKuppuswamy Sathyanarayanan Support running as a guest under Intel TDX. Without this support, 88959bd54a8SKuppuswamy Sathyanarayanan the guest kernel can not boot or run under TDX. 89059bd54a8SKuppuswamy Sathyanarayanan TDX includes memory encryption and integrity capabilities 89159bd54a8SKuppuswamy Sathyanarayanan which protect the confidentiality and integrity of guest 89259bd54a8SKuppuswamy Sathyanarayanan memory contents and CPU state. TDX guests are protected from 89359bd54a8SKuppuswamy Sathyanarayanan some attacks from the VMM. 89459bd54a8SKuppuswamy Sathyanarayanan 8956276a074SBorislav Petkovendif # HYPERVISOR_GUEST 89697349135SJeremy Fitzhardinge 897506f1d07SSam Ravnborgsource "arch/x86/Kconfig.cpu" 898506f1d07SSam Ravnborg 899506f1d07SSam Ravnborgconfig HPET_TIMER 9003c2362e6SHarvey Harrison def_bool X86_64 901506f1d07SSam Ravnborg prompt "HPET Timer Support" if X86_32 902a7f7f624SMasahiro Yamada help 903506f1d07SSam Ravnborg Use the IA-PC HPET (High Precision Event Timer) to manage 904506f1d07SSam Ravnborg time in preference to the PIT and RTC, if a HPET is 905506f1d07SSam Ravnborg present. 906506f1d07SSam Ravnborg HPET is the next generation timer replacing legacy 8254s. 907506f1d07SSam Ravnborg The HPET provides a stable time base on SMP 908506f1d07SSam Ravnborg systems, unlike the TSC, but it is more expensive to access, 9094e7f9df2SMichael S. Tsirkin as it is off-chip. The interface used is documented 9104e7f9df2SMichael S. Tsirkin in the HPET spec, revision 1. 911506f1d07SSam Ravnborg 912506f1d07SSam Ravnborg You can safely choose Y here. However, HPET will only be 913506f1d07SSam Ravnborg activated if the platform and the BIOS support this feature. 914506f1d07SSam Ravnborg Otherwise the 8254 will be used for timing services. 915506f1d07SSam Ravnborg 916506f1d07SSam Ravnborg Choose N to continue using the legacy 8254 timer. 917506f1d07SSam Ravnborg 918506f1d07SSam Ravnborgconfig HPET_EMULATE_RTC 9193c2362e6SHarvey Harrison def_bool y 9203228e1dcSAnand K Mistry depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 921506f1d07SSam Ravnborg 9226a108a14SDavid Rientjes# Mark as expert because too many people got it wrong. 923506f1d07SSam Ravnborg# The code disables itself when not needed. 9247ae9392cSThomas Petazzoniconfig DMI 9257ae9392cSThomas Petazzoni default y 926cf074402SArd Biesheuvel select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 9276a108a14SDavid Rientjes bool "Enable DMI scanning" if EXPERT 928a7f7f624SMasahiro Yamada help 9297ae9392cSThomas Petazzoni Enabled scanning of DMI to identify machine quirks. Say Y 9307ae9392cSThomas Petazzoni here unless you have verified that your setup is not 9317ae9392cSThomas Petazzoni affected by entries in the DMI blacklist. Required by PNP 9327ae9392cSThomas Petazzoni BIOS code. 9337ae9392cSThomas Petazzoni 934506f1d07SSam Ravnborgconfig GART_IOMMU 93538901f1cSAndi Kleen bool "Old AMD GART IOMMU support" 9362f9237d4SChristoph Hellwig select DMA_OPS 937a4ce5a48SChristoph Hellwig select IOMMU_HELPER 938506f1d07SSam Ravnborg select SWIOTLB 93923ac4ae8SAndreas Herrmann depends on X86_64 && PCI && AMD_NB 940a7f7f624SMasahiro Yamada help 941ced3c42cSIngo Molnar Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 942ced3c42cSIngo Molnar GART based hardware IOMMUs. 943ced3c42cSIngo Molnar 944ced3c42cSIngo Molnar The GART supports full DMA access for devices with 32-bit access 945ced3c42cSIngo Molnar limitations, on systems with more than 3 GB. This is usually needed 946ced3c42cSIngo Molnar for USB, sound, many IDE/SATA chipsets and some other devices. 947ced3c42cSIngo Molnar 948ced3c42cSIngo Molnar Newer systems typically have a modern AMD IOMMU, supported via 949ced3c42cSIngo Molnar the CONFIG_AMD_IOMMU=y config option. 950ced3c42cSIngo Molnar 951ced3c42cSIngo Molnar In normal configurations this driver is only active when needed: 952ced3c42cSIngo Molnar there's more than 3 GB of memory and the system contains a 953ced3c42cSIngo Molnar 32-bit limited device. 954ced3c42cSIngo Molnar 955ced3c42cSIngo Molnar If unsure, say Y. 956506f1d07SSam Ravnborg 9578b766b0fSMichal Suchanekconfig BOOT_VESA_SUPPORT 9588b766b0fSMichal Suchanek bool 9598b766b0fSMichal Suchanek help 9608b766b0fSMichal Suchanek If true, at least one selected framebuffer driver can take advantage 9618b766b0fSMichal Suchanek of VESA video modes set at an early boot stage via the vga= parameter. 9628b766b0fSMichal Suchanek 9631184dc2fSMike Travisconfig MAXSMP 964ddb0c5a6SSamuel Thibault bool "Enable Maximum number of SMP Processors and NUMA Nodes" 9656ea30386SKees Cook depends on X86_64 && SMP && DEBUG_KERNEL 96636f5101aSMike Travis select CPUMASK_OFFSTACK 967a7f7f624SMasahiro Yamada help 968ddb0c5a6SSamuel Thibault Enable maximum number of CPUS and NUMA Nodes for this architecture. 9691184dc2fSMike Travis If unsure, say N. 970506f1d07SSam Ravnborg 971aec6487eSIngo Molnar# 972aec6487eSIngo Molnar# The maximum number of CPUs supported: 973aec6487eSIngo Molnar# 974aec6487eSIngo Molnar# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 975aec6487eSIngo Molnar# and which can be configured interactively in the 976aec6487eSIngo Molnar# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 977aec6487eSIngo Molnar# 978aec6487eSIngo Molnar# The ranges are different on 32-bit and 64-bit kernels, depending on 979aec6487eSIngo Molnar# hardware capabilities and scalability features of the kernel. 980aec6487eSIngo Molnar# 981aec6487eSIngo Molnar# ( If MAXSMP is enabled we just use the highest possible value and disable 982aec6487eSIngo Molnar# interactive configuration. ) 983aec6487eSIngo Molnar# 984a0d0bb4dSRandy Dunlap 985aec6487eSIngo Molnarconfig NR_CPUS_RANGE_BEGIN 986a0d0bb4dSRandy Dunlap int 987aec6487eSIngo Molnar default NR_CPUS_RANGE_END if MAXSMP 988a0d0bb4dSRandy Dunlap default 1 if !SMP 989a0d0bb4dSRandy Dunlap default 2 990a0d0bb4dSRandy Dunlap 991aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 992a0d0bb4dSRandy Dunlap int 993a0d0bb4dSRandy Dunlap depends on X86_32 994aec6487eSIngo Molnar default 64 if SMP && X86_BIGSMP 995aec6487eSIngo Molnar default 8 if SMP && !X86_BIGSMP 996a0d0bb4dSRandy Dunlap default 1 if !SMP 997a0d0bb4dSRandy Dunlap 998aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 999a0d0bb4dSRandy Dunlap int 1000a0d0bb4dSRandy Dunlap depends on X86_64 10011edae1aeSScott Wood default 8192 if SMP && CPUMASK_OFFSTACK 10021edae1aeSScott Wood default 512 if SMP && !CPUMASK_OFFSTACK 1003a0d0bb4dSRandy Dunlap default 1 if !SMP 1004aec6487eSIngo Molnar 1005aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 1006aec6487eSIngo Molnar int 1007aec6487eSIngo Molnar depends on X86_32 1008aec6487eSIngo Molnar default 32 if X86_BIGSMP 1009aec6487eSIngo Molnar default 8 if SMP 1010aec6487eSIngo Molnar default 1 if !SMP 1011aec6487eSIngo Molnar 1012aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 1013aec6487eSIngo Molnar int 1014aec6487eSIngo Molnar depends on X86_64 1015a0d0bb4dSRandy Dunlap default 8192 if MAXSMP 1016a0d0bb4dSRandy Dunlap default 64 if SMP 1017aec6487eSIngo Molnar default 1 if !SMP 1018a0d0bb4dSRandy Dunlap 1019506f1d07SSam Ravnborgconfig NR_CPUS 102036f5101aSMike Travis int "Maximum number of CPUs" if SMP && !MAXSMP 1021aec6487eSIngo Molnar range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1022aec6487eSIngo Molnar default NR_CPUS_DEFAULT 1023a7f7f624SMasahiro Yamada help 1024506f1d07SSam Ravnborg This allows you to specify the maximum number of CPUs which this 1025bb61ccc7SJosh Boyer kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1026cad14bb9SKirill A. Shutemov supported value is 8192, otherwise the maximum value is 512. The 1027506f1d07SSam Ravnborg minimum value which makes sense is 2. 1028506f1d07SSam Ravnborg 1029aec6487eSIngo Molnar This is purely to save memory: each supported CPU adds about 8KB 1030aec6487eSIngo Molnar to the kernel image. 1031506f1d07SSam Ravnborg 103266558b73STim Chenconfig SCHED_CLUSTER 103366558b73STim Chen bool "Cluster scheduler support" 103466558b73STim Chen depends on SMP 103566558b73STim Chen default y 103666558b73STim Chen help 103766558b73STim Chen Cluster scheduler support improves the CPU scheduler's decision 103866558b73STim Chen making when dealing with machines that have clusters of CPUs. 103966558b73STim Chen Cluster usually means a couple of CPUs which are placed closely 104066558b73STim Chen by sharing mid-level caches, last-level cache tags or internal 104166558b73STim Chen busses. 104266558b73STim Chen 1043506f1d07SSam Ravnborgconfig SCHED_SMT 1044dbe73364SThomas Gleixner def_bool y if SMP 1045506f1d07SSam Ravnborg 1046506f1d07SSam Ravnborgconfig SCHED_MC 10473c2362e6SHarvey Harrison def_bool y 10483c2362e6SHarvey Harrison prompt "Multi-core scheduler support" 1049c8e56d20SBorislav Petkov depends on SMP 1050a7f7f624SMasahiro Yamada help 1051506f1d07SSam Ravnborg Multi-core scheduler support improves the CPU scheduler's decision 1052506f1d07SSam Ravnborg making when dealing with multi-core CPU chips at a cost of slightly 1053506f1d07SSam Ravnborg increased overhead in some places. If unsure say N here. 1054506f1d07SSam Ravnborg 1055de966cf4STim Chenconfig SCHED_MC_PRIO 1056de966cf4STim Chen bool "CPU core priorities scheduler support" 10570a21fc12SIngo Molnar depends on SCHED_MC && CPU_SUP_INTEL 10580a21fc12SIngo Molnar select X86_INTEL_PSTATE 10590a21fc12SIngo Molnar select CPU_FREQ 1060de966cf4STim Chen default y 1061a7f7f624SMasahiro Yamada help 1062de966cf4STim Chen Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1063de966cf4STim Chen core ordering determined at manufacturing time, which allows 1064de966cf4STim Chen certain cores to reach higher turbo frequencies (when running 1065de966cf4STim Chen single threaded workloads) than others. 1066de966cf4STim Chen 1067de966cf4STim Chen Enabling this kernel feature teaches the scheduler about 1068de966cf4STim Chen the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1069de966cf4STim Chen scheduler's CPU selection logic accordingly, so that higher 1070de966cf4STim Chen overall system performance can be achieved. 1071de966cf4STim Chen 1072de966cf4STim Chen This feature will have no effect on CPUs without this feature. 1073de966cf4STim Chen 1074de966cf4STim Chen If unsure say Y here. 10755e76b2abSTim Chen 107630b8b006SThomas Gleixnerconfig UP_LATE_INIT 107730b8b006SThomas Gleixner def_bool y 1078ba360f88SThomas Gleixner depends on !SMP && X86_LOCAL_APIC 107930b8b006SThomas Gleixner 1080506f1d07SSam Ravnborgconfig X86_UP_APIC 108150849eefSJan Beulich bool "Local APIC support on uniprocessors" if !PCI_MSI 108250849eefSJan Beulich default PCI_MSI 108338a1dfdaSBryan O'Donoghue depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1084a7f7f624SMasahiro Yamada help 1085506f1d07SSam Ravnborg A local APIC (Advanced Programmable Interrupt Controller) is an 1086506f1d07SSam Ravnborg integrated interrupt controller in the CPU. If you have a single-CPU 1087506f1d07SSam Ravnborg system which has a processor with a local APIC, you can say Y here to 1088506f1d07SSam Ravnborg enable and use it. If you say Y here even though your machine doesn't 1089506f1d07SSam Ravnborg have a local APIC, then the kernel will still run with no slowdown at 1090506f1d07SSam Ravnborg all. The local APIC supports CPU-generated self-interrupts (timer, 1091506f1d07SSam Ravnborg performance counters), and the NMI watchdog which detects hard 1092506f1d07SSam Ravnborg lockups. 1093506f1d07SSam Ravnborg 1094506f1d07SSam Ravnborgconfig X86_UP_IOAPIC 1095506f1d07SSam Ravnborg bool "IO-APIC support on uniprocessors" 1096506f1d07SSam Ravnborg depends on X86_UP_APIC 1097a7f7f624SMasahiro Yamada help 1098506f1d07SSam Ravnborg An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1099506f1d07SSam Ravnborg SMP-capable replacement for PC-style interrupt controllers. Most 1100506f1d07SSam Ravnborg SMP systems and many recent uniprocessor systems have one. 1101506f1d07SSam Ravnborg 1102506f1d07SSam Ravnborg If you have a single-CPU system with an IO-APIC, you can say Y here 1103506f1d07SSam Ravnborg to use it. If you say Y here even though your machine doesn't have 1104506f1d07SSam Ravnborg an IO-APIC, then the kernel will still run with no slowdown at all. 1105506f1d07SSam Ravnborg 1106506f1d07SSam Ravnborgconfig X86_LOCAL_APIC 11073c2362e6SHarvey Harrison def_bool y 11080dbc6078SThomas Petazzoni depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1109b5dc8e6cSJiang Liu select IRQ_DOMAIN_HIERARCHY 1110506f1d07SSam Ravnborg 1111506f1d07SSam Ravnborgconfig X86_IO_APIC 1112b1da1e71SJan Beulich def_bool y 1113b1da1e71SJan Beulich depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1114506f1d07SSam Ravnborg 111541b9eb26SStefan Assmannconfig X86_REROUTE_FOR_BROKEN_BOOT_IRQS 111641b9eb26SStefan Assmann bool "Reroute for broken boot IRQs" 111741b9eb26SStefan Assmann depends on X86_IO_APIC 1118a7f7f624SMasahiro Yamada help 111941b9eb26SStefan Assmann This option enables a workaround that fixes a source of 112041b9eb26SStefan Assmann spurious interrupts. This is recommended when threaded 112141b9eb26SStefan Assmann interrupt handling is used on systems where the generation of 112241b9eb26SStefan Assmann superfluous "boot interrupts" cannot be disabled. 112341b9eb26SStefan Assmann 112441b9eb26SStefan Assmann Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 112541b9eb26SStefan Assmann entry in the chipset's IO-APIC is masked (as, e.g. the RT 112641b9eb26SStefan Assmann kernel does during interrupt handling). On chipsets where this 112741b9eb26SStefan Assmann boot IRQ generation cannot be disabled, this workaround keeps 112841b9eb26SStefan Assmann the original IRQ line masked so that only the equivalent "boot 112941b9eb26SStefan Assmann IRQ" is delivered to the CPUs. The workaround also tells the 113041b9eb26SStefan Assmann kernel to set up the IRQ handler on the boot IRQ line. In this 113141b9eb26SStefan Assmann way only one interrupt is delivered to the kernel. Otherwise 113241b9eb26SStefan Assmann the spurious second interrupt may cause the kernel to bring 113341b9eb26SStefan Assmann down (vital) interrupt lines. 113441b9eb26SStefan Assmann 113541b9eb26SStefan Assmann Only affects "broken" chipsets. Interrupt sharing may be 113641b9eb26SStefan Assmann increased on these systems. 113741b9eb26SStefan Assmann 1138506f1d07SSam Ravnborgconfig X86_MCE 1139bab9bc65SAndi Kleen bool "Machine Check / overheating reporting" 1140648ed940SChen, Gong select GENERIC_ALLOCATOR 1141e57dbaf7SBorislav Petkov default y 1142a7f7f624SMasahiro Yamada help 1143bab9bc65SAndi Kleen Machine Check support allows the processor to notify the 1144bab9bc65SAndi Kleen kernel if it detects a problem (e.g. overheating, data corruption). 1145506f1d07SSam Ravnborg The action the kernel takes depends on the severity of the problem, 1146bab9bc65SAndi Kleen ranging from warning messages to halting the machine. 11474efc0670SAndi Kleen 11485de97c9fSTony Luckconfig X86_MCELOG_LEGACY 11495de97c9fSTony Luck bool "Support for deprecated /dev/mcelog character device" 11505de97c9fSTony Luck depends on X86_MCE 1151a7f7f624SMasahiro Yamada help 11525de97c9fSTony Luck Enable support for /dev/mcelog which is needed by the old mcelog 11535de97c9fSTony Luck userspace logging daemon. Consider switching to the new generation 11545de97c9fSTony Luck rasdaemon solution. 11555de97c9fSTony Luck 1156506f1d07SSam Ravnborgconfig X86_MCE_INTEL 11573c2362e6SHarvey Harrison def_bool y 11583c2362e6SHarvey Harrison prompt "Intel MCE features" 1159c1ebf835SAndi Kleen depends on X86_MCE && X86_LOCAL_APIC 1160a7f7f624SMasahiro Yamada help 1161506f1d07SSam Ravnborg Additional support for intel specific MCE features such as 1162506f1d07SSam Ravnborg the thermal monitor. 1163506f1d07SSam Ravnborg 1164506f1d07SSam Ravnborgconfig X86_MCE_AMD 11653c2362e6SHarvey Harrison def_bool y 11663c2362e6SHarvey Harrison prompt "AMD MCE features" 1167f5382de9SYazen Ghannam depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1168a7f7f624SMasahiro Yamada help 1169506f1d07SSam Ravnborg Additional support for AMD specific MCE features such as 1170506f1d07SSam Ravnborg the DRAM Error Threshold. 1171506f1d07SSam Ravnborg 11724efc0670SAndi Kleenconfig X86_ANCIENT_MCE 11736fc108a0SJan Beulich bool "Support for old Pentium 5 / WinChip machine checks" 1174c31d9633SAndi Kleen depends on X86_32 && X86_MCE 1175a7f7f624SMasahiro Yamada help 11764efc0670SAndi Kleen Include support for machine check handling on old Pentium 5 or WinChip 11775065a706SMasanari Iida systems. These typically need to be enabled explicitly on the command 11784efc0670SAndi Kleen line. 11794efc0670SAndi Kleen 1180b2762686SAndi Kleenconfig X86_MCE_THRESHOLD 1181b2762686SAndi Kleen depends on X86_MCE_AMD || X86_MCE_INTEL 11826fc108a0SJan Beulich def_bool y 1183b2762686SAndi Kleen 1184ea149b36SAndi Kleenconfig X86_MCE_INJECT 1185bc8e80d5SBorislav Petkov depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1186ea149b36SAndi Kleen tristate "Machine check injector support" 1187a7f7f624SMasahiro Yamada help 1188ea149b36SAndi Kleen Provide support for injecting machine checks for testing purposes. 1189ea149b36SAndi Kleen If you don't know what a machine check is and you don't do kernel 1190ea149b36SAndi Kleen QA it is safe to say n. 1191ea149b36SAndi Kleen 119207dc900eSPeter Zijlstrasource "arch/x86/events/Kconfig" 1193e633c65aSKan Liang 11945aef51c3SAndy Lutomirskiconfig X86_LEGACY_VM86 11951e642812SIngo Molnar bool "Legacy VM86 support" 1196506f1d07SSam Ravnborg depends on X86_32 1197a7f7f624SMasahiro Yamada help 11985aef51c3SAndy Lutomirski This option allows user programs to put the CPU into V8086 11995aef51c3SAndy Lutomirski mode, which is an 80286-era approximation of 16-bit real mode. 12005aef51c3SAndy Lutomirski 12015aef51c3SAndy Lutomirski Some very old versions of X and/or vbetool require this option 12025aef51c3SAndy Lutomirski for user mode setting. Similarly, DOSEMU will use it if 12035aef51c3SAndy Lutomirski available to accelerate real mode DOS programs. However, any 12045aef51c3SAndy Lutomirski recent version of DOSEMU, X, or vbetool should be fully 12055aef51c3SAndy Lutomirski functional even without kernel VM86 support, as they will all 12061e642812SIngo Molnar fall back to software emulation. Nevertheless, if you are using 12071e642812SIngo Molnar a 16-bit DOS program where 16-bit performance matters, vm86 12081e642812SIngo Molnar mode might be faster than emulation and you might want to 12091e642812SIngo Molnar enable this option. 12105aef51c3SAndy Lutomirski 12111e642812SIngo Molnar Note that any app that works on a 64-bit kernel is unlikely to 12121e642812SIngo Molnar need this option, as 64-bit kernels don't, and can't, support 12131e642812SIngo Molnar V8086 mode. This option is also unrelated to 16-bit protected 12141e642812SIngo Molnar mode and is not needed to run most 16-bit programs under Wine. 12155aef51c3SAndy Lutomirski 12161e642812SIngo Molnar Enabling this option increases the complexity of the kernel 12171e642812SIngo Molnar and slows down exception handling a tiny bit. 12185aef51c3SAndy Lutomirski 12191e642812SIngo Molnar If unsure, say N here. 12205aef51c3SAndy Lutomirski 12215aef51c3SAndy Lutomirskiconfig VM86 12225aef51c3SAndy Lutomirski bool 12235aef51c3SAndy Lutomirski default X86_LEGACY_VM86 122434273f41SH. Peter Anvin 122534273f41SH. Peter Anvinconfig X86_16BIT 122634273f41SH. Peter Anvin bool "Enable support for 16-bit segments" if EXPERT 122734273f41SH. Peter Anvin default y 1228a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 1229a7f7f624SMasahiro Yamada help 123034273f41SH. Peter Anvin This option is required by programs like Wine to run 16-bit 123134273f41SH. Peter Anvin protected mode legacy code on x86 processors. Disabling 123234273f41SH. Peter Anvin this option saves about 300 bytes on i386, or around 6K text 123334273f41SH. Peter Anvin plus 16K runtime memory on x86-64, 123434273f41SH. Peter Anvin 123534273f41SH. Peter Anvinconfig X86_ESPFIX32 123634273f41SH. Peter Anvin def_bool y 123734273f41SH. Peter Anvin depends on X86_16BIT && X86_32 1238506f1d07SSam Ravnborg 1239197725deSH. Peter Anvinconfig X86_ESPFIX64 1240197725deSH. Peter Anvin def_bool y 124134273f41SH. Peter Anvin depends on X86_16BIT && X86_64 1242506f1d07SSam Ravnborg 12431ad83c85SAndy Lutomirskiconfig X86_VSYSCALL_EMULATION 12441ad83c85SAndy Lutomirski bool "Enable vsyscall emulation" if EXPERT 12451ad83c85SAndy Lutomirski default y 12461ad83c85SAndy Lutomirski depends on X86_64 1247a7f7f624SMasahiro Yamada help 12481ad83c85SAndy Lutomirski This enables emulation of the legacy vsyscall page. Disabling 12491ad83c85SAndy Lutomirski it is roughly equivalent to booting with vsyscall=none, except 12501ad83c85SAndy Lutomirski that it will also disable the helpful warning if a program 12511ad83c85SAndy Lutomirski tries to use a vsyscall. With this option set to N, offending 12521ad83c85SAndy Lutomirski programs will just segfault, citing addresses of the form 12531ad83c85SAndy Lutomirski 0xffffffffff600?00. 12541ad83c85SAndy Lutomirski 12551ad83c85SAndy Lutomirski This option is required by many programs built before 2013, and 12561ad83c85SAndy Lutomirski care should be used even with newer programs if set to N. 12571ad83c85SAndy Lutomirski 12581ad83c85SAndy Lutomirski Disabling this option saves about 7K of kernel size and 12591ad83c85SAndy Lutomirski possibly 4K of additional runtime pagetable memory. 12601ad83c85SAndy Lutomirski 1261111e7b15SThomas Gleixnerconfig X86_IOPL_IOPERM 1262111e7b15SThomas Gleixner bool "IOPERM and IOPL Emulation" 1263a24ca997SThomas Gleixner default y 1264a7f7f624SMasahiro Yamada help 1265111e7b15SThomas Gleixner This enables the ioperm() and iopl() syscalls which are necessary 1266111e7b15SThomas Gleixner for legacy applications. 1267111e7b15SThomas Gleixner 1268c8137aceSThomas Gleixner Legacy IOPL support is an overbroad mechanism which allows user 1269c8137aceSThomas Gleixner space aside of accessing all 65536 I/O ports also to disable 1270c8137aceSThomas Gleixner interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1271c8137aceSThomas Gleixner capabilities and permission from potentially active security 1272c8137aceSThomas Gleixner modules. 1273c8137aceSThomas Gleixner 1274c8137aceSThomas Gleixner The emulation restricts the functionality of the syscall to 1275c8137aceSThomas Gleixner only allowing the full range I/O port access, but prevents the 1276a24ca997SThomas Gleixner ability to disable interrupts from user space which would be 1277a24ca997SThomas Gleixner granted if the hardware IOPL mechanism would be used. 1278c8137aceSThomas Gleixner 1279506f1d07SSam Ravnborgconfig TOSHIBA 1280506f1d07SSam Ravnborg tristate "Toshiba Laptop support" 1281506f1d07SSam Ravnborg depends on X86_32 1282a7f7f624SMasahiro Yamada help 1283506f1d07SSam Ravnborg This adds a driver to safely access the System Management Mode of 1284506f1d07SSam Ravnborg the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1285506f1d07SSam Ravnborg not work on models with a Phoenix BIOS. The System Management Mode 1286506f1d07SSam Ravnborg is used to set the BIOS and power saving options on Toshiba portables. 1287506f1d07SSam Ravnborg 1288506f1d07SSam Ravnborg For information on utilities to make use of this driver see the 1289506f1d07SSam Ravnborg Toshiba Linux utilities web site at: 1290506f1d07SSam Ravnborg <http://www.buzzard.org.uk/toshiba/>. 1291506f1d07SSam Ravnborg 1292506f1d07SSam Ravnborg Say Y if you intend to run this kernel on a Toshiba portable. 1293506f1d07SSam Ravnborg Say N otherwise. 1294506f1d07SSam Ravnborg 1295506f1d07SSam Ravnborgconfig X86_REBOOTFIXUPS 12969ba16087SJan Beulich bool "Enable X86 board specific fixups for reboot" 12979ba16087SJan Beulich depends on X86_32 1298a7f7f624SMasahiro Yamada help 1299506f1d07SSam Ravnborg This enables chipset and/or board specific fixups to be done 1300506f1d07SSam Ravnborg in order to get reboot to work correctly. This is only needed on 1301506f1d07SSam Ravnborg some combinations of hardware and BIOS. The symptom, for which 1302506f1d07SSam Ravnborg this config is intended, is when reboot ends with a stalled/hung 1303506f1d07SSam Ravnborg system. 1304506f1d07SSam Ravnborg 1305506f1d07SSam Ravnborg Currently, the only fixup is for the Geode machines using 13065e3a77e9SFlorian Fainelli CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1307506f1d07SSam Ravnborg 1308506f1d07SSam Ravnborg Say Y if you want to enable the fixup. Currently, it's safe to 1309506f1d07SSam Ravnborg enable this option even if you don't need it. 1310506f1d07SSam Ravnborg Say N otherwise. 1311506f1d07SSam Ravnborg 1312506f1d07SSam Ravnborgconfig MICROCODE 1313e6bcfdd7SThomas Gleixner def_bool y 131480030e3dSBorislav Petkov depends on CPU_SUP_AMD || CPU_SUP_INTEL 131580cc9f10SPeter Oruba 1316a77a94f8SBorislav Petkovconfig MICROCODE_LATE_LOADING 1317a77a94f8SBorislav Petkov bool "Late microcode loading (DANGEROUS)" 1318c02f48e0SBorislav Petkov default n 1319506f1d07SSam Ravnborg depends on MICROCODE 1320a7f7f624SMasahiro Yamada help 1321a77a94f8SBorislav Petkov Loading microcode late, when the system is up and executing instructions 1322a77a94f8SBorislav Petkov is a tricky business and should be avoided if possible. Just the sequence 1323a77a94f8SBorislav Petkov of synchronizing all cores and SMT threads is one fragile dance which does 1324a77a94f8SBorislav Petkov not guarantee that cores might not softlock after the loading. Therefore, 1325a77a94f8SBorislav Petkov use this at your own risk. Late loading taints the kernel too. 1326506f1d07SSam Ravnborg 1327506f1d07SSam Ravnborgconfig X86_MSR 1328506f1d07SSam Ravnborg tristate "/dev/cpu/*/msr - Model-specific register support" 1329a7f7f624SMasahiro Yamada help 1330506f1d07SSam Ravnborg This device gives privileged processes access to the x86 1331506f1d07SSam Ravnborg Model-Specific Registers (MSRs). It is a character device with 1332506f1d07SSam Ravnborg major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1333506f1d07SSam Ravnborg MSR accesses are directed to a specific CPU on multi-processor 1334506f1d07SSam Ravnborg systems. 1335506f1d07SSam Ravnborg 1336506f1d07SSam Ravnborgconfig X86_CPUID 1337506f1d07SSam Ravnborg tristate "/dev/cpu/*/cpuid - CPU information support" 1338a7f7f624SMasahiro Yamada help 1339506f1d07SSam Ravnborg This device gives processes access to the x86 CPUID instruction to 1340506f1d07SSam Ravnborg be executed on a specific processor. It is a character device 1341506f1d07SSam Ravnborg with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1342506f1d07SSam Ravnborg /dev/cpu/31/cpuid. 1343506f1d07SSam Ravnborg 1344506f1d07SSam Ravnborgchoice 1345506f1d07SSam Ravnborg prompt "High Memory Support" 13466fc108a0SJan Beulich default HIGHMEM4G 1347506f1d07SSam Ravnborg depends on X86_32 1348506f1d07SSam Ravnborg 1349506f1d07SSam Ravnborgconfig NOHIGHMEM 1350506f1d07SSam Ravnborg bool "off" 1351a7f7f624SMasahiro Yamada help 1352506f1d07SSam Ravnborg Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1353506f1d07SSam Ravnborg However, the address space of 32-bit x86 processors is only 4 1354506f1d07SSam Ravnborg Gigabytes large. That means that, if you have a large amount of 1355506f1d07SSam Ravnborg physical memory, not all of it can be "permanently mapped" by the 1356506f1d07SSam Ravnborg kernel. The physical memory that's not permanently mapped is called 1357506f1d07SSam Ravnborg "high memory". 1358506f1d07SSam Ravnborg 1359506f1d07SSam Ravnborg If you are compiling a kernel which will never run on a machine with 1360506f1d07SSam Ravnborg more than 1 Gigabyte total physical RAM, answer "off" here (default 1361506f1d07SSam Ravnborg choice and suitable for most users). This will result in a "3GB/1GB" 1362506f1d07SSam Ravnborg split: 3GB are mapped so that each process sees a 3GB virtual memory 1363506f1d07SSam Ravnborg space and the remaining part of the 4GB virtual memory space is used 1364506f1d07SSam Ravnborg by the kernel to permanently map as much physical memory as 1365506f1d07SSam Ravnborg possible. 1366506f1d07SSam Ravnborg 1367506f1d07SSam Ravnborg If the machine has between 1 and 4 Gigabytes physical RAM, then 1368506f1d07SSam Ravnborg answer "4GB" here. 1369506f1d07SSam Ravnborg 1370506f1d07SSam Ravnborg If more than 4 Gigabytes is used then answer "64GB" here. This 1371506f1d07SSam Ravnborg selection turns Intel PAE (Physical Address Extension) mode on. 1372506f1d07SSam Ravnborg PAE implements 3-level paging on IA32 processors. PAE is fully 1373506f1d07SSam Ravnborg supported by Linux, PAE mode is implemented on all recent Intel 1374506f1d07SSam Ravnborg processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1375506f1d07SSam Ravnborg then the kernel will not boot on CPUs that don't support PAE! 1376506f1d07SSam Ravnborg 1377506f1d07SSam Ravnborg The actual amount of total physical memory will either be 1378506f1d07SSam Ravnborg auto detected or can be forced by using a kernel command line option 1379506f1d07SSam Ravnborg such as "mem=256M". (Try "man bootparam" or see the documentation of 1380506f1d07SSam Ravnborg your boot loader (lilo or loadlin) about how to pass options to the 1381506f1d07SSam Ravnborg kernel at boot time.) 1382506f1d07SSam Ravnborg 1383506f1d07SSam Ravnborg If unsure, say "off". 1384506f1d07SSam Ravnborg 1385506f1d07SSam Ravnborgconfig HIGHMEM4G 1386506f1d07SSam Ravnborg bool "4GB" 1387a7f7f624SMasahiro Yamada help 1388506f1d07SSam Ravnborg Select this if you have a 32-bit processor and between 1 and 4 1389506f1d07SSam Ravnborg gigabytes of physical RAM. 1390506f1d07SSam Ravnborg 1391506f1d07SSam Ravnborgconfig HIGHMEM64G 1392506f1d07SSam Ravnborg bool "64GB" 1393225bac2dSLukas Bulwahn depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6 1394506f1d07SSam Ravnborg select X86_PAE 1395a7f7f624SMasahiro Yamada help 1396506f1d07SSam Ravnborg Select this if you have a 32-bit processor and more than 4 1397506f1d07SSam Ravnborg gigabytes of physical RAM. 1398506f1d07SSam Ravnborg 1399506f1d07SSam Ravnborgendchoice 1400506f1d07SSam Ravnborg 1401506f1d07SSam Ravnborgchoice 14026a108a14SDavid Rientjes prompt "Memory split" if EXPERT 1403506f1d07SSam Ravnborg default VMSPLIT_3G 1404506f1d07SSam Ravnborg depends on X86_32 1405a7f7f624SMasahiro Yamada help 1406506f1d07SSam Ravnborg Select the desired split between kernel and user memory. 1407506f1d07SSam Ravnborg 1408506f1d07SSam Ravnborg If the address range available to the kernel is less than the 1409506f1d07SSam Ravnborg physical memory installed, the remaining memory will be available 1410506f1d07SSam Ravnborg as "high memory". Accessing high memory is a little more costly 1411506f1d07SSam Ravnborg than low memory, as it needs to be mapped into the kernel first. 1412506f1d07SSam Ravnborg Note that increasing the kernel address space limits the range 1413506f1d07SSam Ravnborg available to user programs, making the address space there 1414506f1d07SSam Ravnborg tighter. Selecting anything other than the default 3G/1G split 1415506f1d07SSam Ravnborg will also likely make your kernel incompatible with binary-only 1416506f1d07SSam Ravnborg kernel modules. 1417506f1d07SSam Ravnborg 1418506f1d07SSam Ravnborg If you are not absolutely sure what you are doing, leave this 1419506f1d07SSam Ravnborg option alone! 1420506f1d07SSam Ravnborg 1421506f1d07SSam Ravnborg config VMSPLIT_3G 1422506f1d07SSam Ravnborg bool "3G/1G user/kernel split" 1423506f1d07SSam Ravnborg config VMSPLIT_3G_OPT 1424506f1d07SSam Ravnborg depends on !X86_PAE 1425506f1d07SSam Ravnborg bool "3G/1G user/kernel split (for full 1G low memory)" 1426506f1d07SSam Ravnborg config VMSPLIT_2G 1427506f1d07SSam Ravnborg bool "2G/2G user/kernel split" 1428506f1d07SSam Ravnborg config VMSPLIT_2G_OPT 1429506f1d07SSam Ravnborg depends on !X86_PAE 1430506f1d07SSam Ravnborg bool "2G/2G user/kernel split (for full 2G low memory)" 1431506f1d07SSam Ravnborg config VMSPLIT_1G 1432506f1d07SSam Ravnborg bool "1G/3G user/kernel split" 1433506f1d07SSam Ravnborgendchoice 1434506f1d07SSam Ravnborg 1435506f1d07SSam Ravnborgconfig PAGE_OFFSET 1436506f1d07SSam Ravnborg hex 1437506f1d07SSam Ravnborg default 0xB0000000 if VMSPLIT_3G_OPT 1438506f1d07SSam Ravnborg default 0x80000000 if VMSPLIT_2G 1439506f1d07SSam Ravnborg default 0x78000000 if VMSPLIT_2G_OPT 1440506f1d07SSam Ravnborg default 0x40000000 if VMSPLIT_1G 1441506f1d07SSam Ravnborg default 0xC0000000 1442506f1d07SSam Ravnborg depends on X86_32 1443506f1d07SSam Ravnborg 1444506f1d07SSam Ravnborgconfig HIGHMEM 14453c2362e6SHarvey Harrison def_bool y 1446506f1d07SSam Ravnborg depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1447506f1d07SSam Ravnborg 1448506f1d07SSam Ravnborgconfig X86_PAE 14499ba16087SJan Beulich bool "PAE (Physical Address Extension) Support" 1450506f1d07SSam Ravnborg depends on X86_32 && !HIGHMEM4G 1451d4a451d5SChristoph Hellwig select PHYS_ADDR_T_64BIT 14529d99c712SChristian Melki select SWIOTLB 1453a7f7f624SMasahiro Yamada help 1454506f1d07SSam Ravnborg PAE is required for NX support, and furthermore enables 1455506f1d07SSam Ravnborg larger swapspace support for non-overcommit purposes. It 1456506f1d07SSam Ravnborg has the cost of more pagetable lookup overhead, and also 1457506f1d07SSam Ravnborg consumes more pagetable space per process. 1458506f1d07SSam Ravnborg 145977ef56e4SKirill A. Shutemovconfig X86_5LEVEL 146077ef56e4SKirill A. Shutemov bool "Enable 5-level page tables support" 146118ec1eafSKirill A. Shutemov default y 1462eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 1463162434e7SKirill A. Shutemov select SPARSEMEM_VMEMMAP 146477ef56e4SKirill A. Shutemov depends on X86_64 1465a7f7f624SMasahiro Yamada help 146677ef56e4SKirill A. Shutemov 5-level paging enables access to larger address space: 146777ef56e4SKirill A. Shutemov up to 128 PiB of virtual address space and 4 PiB of 146877ef56e4SKirill A. Shutemov physical address space. 146977ef56e4SKirill A. Shutemov 147077ef56e4SKirill A. Shutemov It will be supported by future Intel CPUs. 147177ef56e4SKirill A. Shutemov 14726657fca0SKirill A. Shutemov A kernel with the option enabled can be booted on machines that 14736657fca0SKirill A. Shutemov support 4- or 5-level paging. 147477ef56e4SKirill A. Shutemov 1475ff61f079SJonathan Corbet See Documentation/arch/x86/x86_64/5level-paging.rst for more 147677ef56e4SKirill A. Shutemov information. 147777ef56e4SKirill A. Shutemov 147877ef56e4SKirill A. Shutemov Say N if unsure. 147977ef56e4SKirill A. Shutemov 148010971ab2SIngo Molnarconfig X86_DIRECT_GBPAGES 1481e5008abeSLuis R. Rodriguez def_bool y 14822e1da13fSVlastimil Babka depends on X86_64 1483a7f7f624SMasahiro Yamada help 148410971ab2SIngo Molnar Certain kernel features effectively disable kernel 148510971ab2SIngo Molnar linear 1 GB mappings (even if the CPU otherwise 148610971ab2SIngo Molnar supports them), so don't confuse the user by printing 148710971ab2SIngo Molnar that we have them enabled. 14889e899816SNick Piggin 14895c280cf6SThomas Gleixnerconfig X86_CPA_STATISTICS 14905c280cf6SThomas Gleixner bool "Enable statistic for Change Page Attribute" 14915c280cf6SThomas Gleixner depends on DEBUG_FS 1492a7f7f624SMasahiro Yamada help 1493b75baaf3SIngo Molnar Expose statistics about the Change Page Attribute mechanism, which 1494a943245aSColin Ian King helps to determine the effectiveness of preserving large and huge 14955c280cf6SThomas Gleixner page mappings when mapping protections are changed. 14965c280cf6SThomas Gleixner 149720f07a04SKirill A. Shutemovconfig X86_MEM_ENCRYPT 149820f07a04SKirill A. Shutemov select ARCH_HAS_FORCE_DMA_UNENCRYPTED 149920f07a04SKirill A. Shutemov select DYNAMIC_PHYSICAL_MASK 150020f07a04SKirill A. Shutemov def_bool n 150120f07a04SKirill A. Shutemov 15027744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT 15037744ccdbSTom Lendacky bool "AMD Secure Memory Encryption (SME) support" 15047744ccdbSTom Lendacky depends on X86_64 && CPU_SUP_AMD 15056c321179STom Lendacky depends on EFI_STUB 150682fef0adSDavid Rientjes select DMA_COHERENT_POOL 1507ce9084baSArd Biesheuvel select ARCH_USE_MEMREMAP_PROT 1508597cfe48SJoerg Roedel select INSTRUCTION_DECODER 1509aa5a4611STom Lendacky select ARCH_HAS_CC_PLATFORM 151020f07a04SKirill A. Shutemov select X86_MEM_ENCRYPT 15116c321179STom Lendacky select UNACCEPTED_MEMORY 1512a7f7f624SMasahiro Yamada help 15137744ccdbSTom Lendacky Say yes to enable support for the encryption of system memory. 15147744ccdbSTom Lendacky This requires an AMD processor that supports Secure Memory 15157744ccdbSTom Lendacky Encryption (SME). 15167744ccdbSTom Lendacky 15177744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 15187744ccdbSTom Lendacky bool "Activate AMD Secure Memory Encryption (SME) by default" 15197744ccdbSTom Lendacky depends on AMD_MEM_ENCRYPT 1520a7f7f624SMasahiro Yamada help 15217744ccdbSTom Lendacky Say yes to have system memory encrypted by default if running on 15227744ccdbSTom Lendacky an AMD processor that supports Secure Memory Encryption (SME). 15237744ccdbSTom Lendacky 15247744ccdbSTom Lendacky If set to Y, then the encryption of system memory can be 15257744ccdbSTom Lendacky deactivated with the mem_encrypt=off command line option. 15267744ccdbSTom Lendacky 15277744ccdbSTom Lendacky If set to N, then the encryption of system memory can be 15287744ccdbSTom Lendacky activated with the mem_encrypt=on command line option. 15297744ccdbSTom Lendacky 1530506f1d07SSam Ravnborg# Common NUMA Features 1531506f1d07SSam Ravnborgconfig NUMA 1532e133f6eaSRandy Dunlap bool "NUMA Memory Allocation and Scheduler Support" 1533506f1d07SSam Ravnborg depends on SMP 1534b5660ba7SH. Peter Anvin depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1535b5660ba7SH. Peter Anvin default y if X86_BIGSMP 15367ecd19cfSKefeng Wang select USE_PERCPU_NUMA_NODE_ID 1537a7f7f624SMasahiro Yamada help 1538e133f6eaSRandy Dunlap Enable NUMA (Non-Uniform Memory Access) support. 1539fd51b2d7SKOSAKI Motohiro 1540506f1d07SSam Ravnborg The kernel will try to allocate memory used by a CPU on the 1541506f1d07SSam Ravnborg local memory controller of the CPU and add some more 1542506f1d07SSam Ravnborg NUMA awareness to the kernel. 1543506f1d07SSam Ravnborg 1544c280ea5eSIngo Molnar For 64-bit this is recommended if the system is Intel Core i7 1545fd51b2d7SKOSAKI Motohiro (or later), AMD Opteron, or EM64T NUMA. 1546fd51b2d7SKOSAKI Motohiro 1547b5660ba7SH. Peter Anvin For 32-bit this is only needed if you boot a 32-bit 15487cf6c945SDavid Rientjes kernel on a 64-bit NUMA platform. 1549fd51b2d7SKOSAKI Motohiro 1550fd51b2d7SKOSAKI Motohiro Otherwise, you should say N. 1551506f1d07SSam Ravnborg 1552eec1d4faSHans Rosenfeldconfig AMD_NUMA 15533c2362e6SHarvey Harrison def_bool y 15543c2362e6SHarvey Harrison prompt "Old style AMD Opteron NUMA detection" 15555da0ef9aSTejun Heo depends on X86_64 && NUMA && PCI 1556a7f7f624SMasahiro Yamada help 1557eec1d4faSHans Rosenfeld Enable AMD NUMA node topology detection. You should say Y here if 1558eec1d4faSHans Rosenfeld you have a multi processor AMD system. This uses an old method to 1559eec1d4faSHans Rosenfeld read the NUMA configuration directly from the builtin Northbridge 1560eec1d4faSHans Rosenfeld of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1561eec1d4faSHans Rosenfeld which also takes priority if both are compiled in. 1562506f1d07SSam Ravnborg 1563506f1d07SSam Ravnborgconfig X86_64_ACPI_NUMA 15643c2362e6SHarvey Harrison def_bool y 15653c2362e6SHarvey Harrison prompt "ACPI NUMA detection" 1566506f1d07SSam Ravnborg depends on X86_64 && NUMA && ACPI && PCI 1567506f1d07SSam Ravnborg select ACPI_NUMA 1568a7f7f624SMasahiro Yamada help 1569506f1d07SSam Ravnborg Enable ACPI SRAT based node topology detection. 1570506f1d07SSam Ravnborg 1571506f1d07SSam Ravnborgconfig NUMA_EMU 1572506f1d07SSam Ravnborg bool "NUMA emulation" 15731b7e03efSTejun Heo depends on NUMA 1574a7f7f624SMasahiro Yamada help 1575506f1d07SSam Ravnborg Enable NUMA emulation. A flat machine will be split 1576506f1d07SSam Ravnborg into virtual nodes when booted with "numa=fake=N", where N is the 1577506f1d07SSam Ravnborg number of nodes. This is only useful for debugging. 1578506f1d07SSam Ravnborg 1579506f1d07SSam Ravnborgconfig NODES_SHIFT 1580d25e26b6SLinus Torvalds int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 158151591e31SDavid Rientjes range 1 10 158251591e31SDavid Rientjes default "10" if MAXSMP 1583506f1d07SSam Ravnborg default "6" if X86_64 1584506f1d07SSam Ravnborg default "3" 1585a9ee6cf5SMike Rapoport depends on NUMA 1586a7f7f624SMasahiro Yamada help 15871184dc2fSMike Travis Specify the maximum number of NUMA Nodes available on the target 1588692105b8SMatt LaPlante system. Increases memory reserved to accommodate various tables. 1589506f1d07SSam Ravnborg 1590506f1d07SSam Ravnborgconfig ARCH_FLATMEM_ENABLE 1591506f1d07SSam Ravnborg def_bool y 15923b16651fSTejun Heo depends on X86_32 && !NUMA 1593506f1d07SSam Ravnborg 1594506f1d07SSam Ravnborgconfig ARCH_SPARSEMEM_ENABLE 1595506f1d07SSam Ravnborg def_bool y 15966ea30386SKees Cook depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1597506f1d07SSam Ravnborg select SPARSEMEM_STATIC if X86_32 1598506f1d07SSam Ravnborg select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1599506f1d07SSam Ravnborg 16003b16651fSTejun Heoconfig ARCH_SPARSEMEM_DEFAULT 16016ad57f7fSMike Rapoport def_bool X86_64 || (NUMA && X86_32) 16023b16651fSTejun Heo 1603506f1d07SSam Ravnborgconfig ARCH_SELECT_MEMORY_MODEL 1604506f1d07SSam Ravnborg def_bool y 16054eda2bc3SDavid Hildenbrand depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE 1606506f1d07SSam Ravnborg 1607506f1d07SSam Ravnborgconfig ARCH_MEMORY_PROBE 1608a0842b70SToshi Kani bool "Enable sysfs memory/probe interface" 16095c11f00bSDavid Hildenbrand depends on MEMORY_HOTPLUG 1610a0842b70SToshi Kani help 1611a0842b70SToshi Kani This option enables a sysfs memory/probe interface for testing. 1612cb1aaebeSMauro Carvalho Chehab See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1613a0842b70SToshi Kani If you are unsure how to answer this question, answer N. 1614506f1d07SSam Ravnborg 16153b16651fSTejun Heoconfig ARCH_PROC_KCORE_TEXT 16163b16651fSTejun Heo def_bool y 16173b16651fSTejun Heo depends on X86_64 && PROC_KCORE 16183b16651fSTejun Heo 1619a29815a3SAvi Kivityconfig ILLEGAL_POINTER_VALUE 1620a29815a3SAvi Kivity hex 1621a29815a3SAvi Kivity default 0 if X86_32 1622a29815a3SAvi Kivity default 0xdead000000000000 if X86_64 1623a29815a3SAvi Kivity 16247a67832cSDan Williamsconfig X86_PMEM_LEGACY_DEVICE 16257a67832cSDan Williams bool 16267a67832cSDan Williams 1627ec776ef6SChristoph Hellwigconfig X86_PMEM_LEGACY 16287a67832cSDan Williams tristate "Support non-standard NVDIMMs and ADR protected memory" 16299f53f9faSDan Williams depends on PHYS_ADDR_T_64BIT 16309f53f9faSDan Williams depends on BLK_DEV 16317a67832cSDan Williams select X86_PMEM_LEGACY_DEVICE 16327b27a862SDan Williams select NUMA_KEEP_MEMINFO if NUMA 16339f53f9faSDan Williams select LIBNVDIMM 1634ec776ef6SChristoph Hellwig help 1635ec776ef6SChristoph Hellwig Treat memory marked using the non-standard e820 type of 12 as used 1636ec776ef6SChristoph Hellwig by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1637ec776ef6SChristoph Hellwig The kernel will offer these regions to the 'pmem' driver so 1638ec776ef6SChristoph Hellwig they can be used for persistent storage. 1639ec776ef6SChristoph Hellwig 1640ec776ef6SChristoph Hellwig Say Y if unsure. 1641ec776ef6SChristoph Hellwig 1642506f1d07SSam Ravnborgconfig HIGHPTE 1643506f1d07SSam Ravnborg bool "Allocate 3rd-level pagetables from highmem" 16446fc108a0SJan Beulich depends on HIGHMEM 1645a7f7f624SMasahiro Yamada help 1646506f1d07SSam Ravnborg The VM uses one page table entry for each page of physical memory. 1647506f1d07SSam Ravnborg For systems with a lot of RAM, this can be wasteful of precious 1648506f1d07SSam Ravnborg low memory. Setting this option will put user-space page table 1649506f1d07SSam Ravnborg entries in high memory. 1650506f1d07SSam Ravnborg 16519f077871SJeremy Fitzhardingeconfig X86_CHECK_BIOS_CORRUPTION 16529f077871SJeremy Fitzhardinge bool "Check for low memory corruption" 1653a7f7f624SMasahiro Yamada help 16549f077871SJeremy Fitzhardinge Periodically check for memory corruption in low memory, which 16559f077871SJeremy Fitzhardinge is suspected to be caused by BIOS. Even when enabled in the 16569f077871SJeremy Fitzhardinge configuration, it is disabled at runtime. Enable it by 16579f077871SJeremy Fitzhardinge setting "memory_corruption_check=1" on the kernel command 16589f077871SJeremy Fitzhardinge line. By default it scans the low 64k of memory every 60 16599f077871SJeremy Fitzhardinge seconds; see the memory_corruption_check_size and 16609f077871SJeremy Fitzhardinge memory_corruption_check_period parameters in 16618c27ceffSMauro Carvalho Chehab Documentation/admin-guide/kernel-parameters.rst to adjust this. 16629f077871SJeremy Fitzhardinge 16639f077871SJeremy Fitzhardinge When enabled with the default parameters, this option has 16649f077871SJeremy Fitzhardinge almost no overhead, as it reserves a relatively small amount 16659f077871SJeremy Fitzhardinge of memory and scans it infrequently. It both detects corruption 16669f077871SJeremy Fitzhardinge and prevents it from affecting the running system. 16679f077871SJeremy Fitzhardinge 16689f077871SJeremy Fitzhardinge It is, however, intended as a diagnostic tool; if repeatable 16699f077871SJeremy Fitzhardinge BIOS-originated corruption always affects the same memory, 16709f077871SJeremy Fitzhardinge you can use memmap= to prevent the kernel from using that 16719f077871SJeremy Fitzhardinge memory. 16729f077871SJeremy Fitzhardinge 1673c885df50SJeremy Fitzhardingeconfig X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1674c885df50SJeremy Fitzhardinge bool "Set the default setting of memory_corruption_check" 1675c885df50SJeremy Fitzhardinge depends on X86_CHECK_BIOS_CORRUPTION 1676c885df50SJeremy Fitzhardinge default y 1677a7f7f624SMasahiro Yamada help 1678c885df50SJeremy Fitzhardinge Set whether the default state of memory_corruption_check is 1679c885df50SJeremy Fitzhardinge on or off. 1680c885df50SJeremy Fitzhardinge 1681506f1d07SSam Ravnborgconfig MATH_EMULATION 1682506f1d07SSam Ravnborg bool 1683a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 168487d6021bSArnd Bergmann prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1685a7f7f624SMasahiro Yamada help 1686506f1d07SSam Ravnborg Linux can emulate a math coprocessor (used for floating point 1687506f1d07SSam Ravnborg operations) if you don't have one. 486DX and Pentium processors have 1688506f1d07SSam Ravnborg a math coprocessor built in, 486SX and 386 do not, unless you added 1689506f1d07SSam Ravnborg a 487DX or 387, respectively. (The messages during boot time can 1690506f1d07SSam Ravnborg give you some hints here ["man dmesg"].) Everyone needs either a 1691506f1d07SSam Ravnborg coprocessor or this emulation. 1692506f1d07SSam Ravnborg 1693506f1d07SSam Ravnborg If you don't have a math coprocessor, you need to say Y here; if you 1694506f1d07SSam Ravnborg say Y here even though you have a coprocessor, the coprocessor will 1695506f1d07SSam Ravnborg be used nevertheless. (This behavior can be changed with the kernel 1696506f1d07SSam Ravnborg command line option "no387", which comes handy if your coprocessor 1697506f1d07SSam Ravnborg is broken. Try "man bootparam" or see the documentation of your boot 1698506f1d07SSam Ravnborg loader (lilo or loadlin) about how to pass options to the kernel at 1699506f1d07SSam Ravnborg boot time.) This means that it is a good idea to say Y here if you 1700506f1d07SSam Ravnborg intend to use this kernel on different machines. 1701506f1d07SSam Ravnborg 1702506f1d07SSam Ravnborg More information about the internals of the Linux math coprocessor 1703506f1d07SSam Ravnborg emulation can be found in <file:arch/x86/math-emu/README>. 1704506f1d07SSam Ravnborg 1705506f1d07SSam Ravnborg If you are not sure, say Y; apart from resulting in a 66 KB bigger 1706506f1d07SSam Ravnborg kernel, it won't hurt. 1707506f1d07SSam Ravnborg 1708506f1d07SSam Ravnborgconfig MTRR 17096fc108a0SJan Beulich def_bool y 17106a108a14SDavid Rientjes prompt "MTRR (Memory Type Range Register) support" if EXPERT 1711a7f7f624SMasahiro Yamada help 1712506f1d07SSam Ravnborg On Intel P6 family processors (Pentium Pro, Pentium II and later) 1713506f1d07SSam Ravnborg the Memory Type Range Registers (MTRRs) may be used to control 1714506f1d07SSam Ravnborg processor access to memory ranges. This is most useful if you have 1715506f1d07SSam Ravnborg a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1716506f1d07SSam Ravnborg allows bus write transfers to be combined into a larger transfer 1717506f1d07SSam Ravnborg before bursting over the PCI/AGP bus. This can increase performance 1718506f1d07SSam Ravnborg of image write operations 2.5 times or more. Saying Y here creates a 1719506f1d07SSam Ravnborg /proc/mtrr file which may be used to manipulate your processor's 1720506f1d07SSam Ravnborg MTRRs. Typically the X server should use this. 1721506f1d07SSam Ravnborg 1722506f1d07SSam Ravnborg This code has a reasonably generic interface so that similar 1723506f1d07SSam Ravnborg control registers on other processors can be easily supported 1724506f1d07SSam Ravnborg as well: 1725506f1d07SSam Ravnborg 1726506f1d07SSam Ravnborg The Cyrix 6x86, 6x86MX and M II processors have Address Range 1727506f1d07SSam Ravnborg Registers (ARRs) which provide a similar functionality to MTRRs. For 1728506f1d07SSam Ravnborg these, the ARRs are used to emulate the MTRRs. 1729506f1d07SSam Ravnborg The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1730506f1d07SSam Ravnborg MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1731506f1d07SSam Ravnborg write-combining. All of these processors are supported by this code 1732506f1d07SSam Ravnborg and it makes sense to say Y here if you have one of them. 1733506f1d07SSam Ravnborg 1734506f1d07SSam Ravnborg Saying Y here also fixes a problem with buggy SMP BIOSes which only 1735506f1d07SSam Ravnborg set the MTRRs for the boot CPU and not for the secondary CPUs. This 1736506f1d07SSam Ravnborg can lead to all sorts of problems, so it's good to say Y here. 1737506f1d07SSam Ravnborg 1738506f1d07SSam Ravnborg You can safely say Y even if your machine doesn't have MTRRs, you'll 1739506f1d07SSam Ravnborg just add about 9 KB to your kernel. 1740506f1d07SSam Ravnborg 1741ff61f079SJonathan Corbet See <file:Documentation/arch/x86/mtrr.rst> for more information. 1742506f1d07SSam Ravnborg 174395ffa243SYinghai Luconfig MTRR_SANITIZER 17442ffb3501SYinghai Lu def_bool y 174595ffa243SYinghai Lu prompt "MTRR cleanup support" 174695ffa243SYinghai Lu depends on MTRR 1747a7f7f624SMasahiro Yamada help 1748aba3728cSThomas Gleixner Convert MTRR layout from continuous to discrete, so X drivers can 1749aba3728cSThomas Gleixner add writeback entries. 175095ffa243SYinghai Lu 1751aba3728cSThomas Gleixner Can be disabled with disable_mtrr_cleanup on the kernel command line. 1752692105b8SMatt LaPlante The largest mtrr entry size for a continuous block can be set with 1753aba3728cSThomas Gleixner mtrr_chunk_size. 175495ffa243SYinghai Lu 17552ffb3501SYinghai Lu If unsure, say Y. 175695ffa243SYinghai Lu 175795ffa243SYinghai Luconfig MTRR_SANITIZER_ENABLE_DEFAULT 1758f5098d62SYinghai Lu int "MTRR cleanup enable value (0-1)" 1759f5098d62SYinghai Lu range 0 1 1760f5098d62SYinghai Lu default "0" 176195ffa243SYinghai Lu depends on MTRR_SANITIZER 1762a7f7f624SMasahiro Yamada help 1763f5098d62SYinghai Lu Enable mtrr cleanup default value 176495ffa243SYinghai Lu 176512031a62SYinghai Luconfig MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 176612031a62SYinghai Lu int "MTRR cleanup spare reg num (0-7)" 176712031a62SYinghai Lu range 0 7 176812031a62SYinghai Lu default "1" 176912031a62SYinghai Lu depends on MTRR_SANITIZER 1770a7f7f624SMasahiro Yamada help 177112031a62SYinghai Lu mtrr cleanup spare entries default, it can be changed via 1772aba3728cSThomas Gleixner mtrr_spare_reg_nr=N on the kernel command line. 177312031a62SYinghai Lu 17742e5d9c85Svenkatesh.pallipadi@intel.comconfig X86_PAT 17756fc108a0SJan Beulich def_bool y 17766a108a14SDavid Rientjes prompt "x86 PAT support" if EXPERT 17772a8a2719SIngo Molnar depends on MTRR 1778a7f7f624SMasahiro Yamada help 17792e5d9c85Svenkatesh.pallipadi@intel.com Use PAT attributes to setup page level cache control. 1780042b78e4SVenki Pallipadi 17812e5d9c85Svenkatesh.pallipadi@intel.com PATs are the modern equivalents of MTRRs and are much more 17822e5d9c85Svenkatesh.pallipadi@intel.com flexible than MTRRs. 17832e5d9c85Svenkatesh.pallipadi@intel.com 17842e5d9c85Svenkatesh.pallipadi@intel.com Say N here if you see bootup problems (boot crash, boot hang, 1785042b78e4SVenki Pallipadi spontaneous reboots) or a non-working video driver. 17862e5d9c85Svenkatesh.pallipadi@intel.com 17872e5d9c85Svenkatesh.pallipadi@intel.com If unsure, say Y. 17882e5d9c85Svenkatesh.pallipadi@intel.com 178946cf98cdSVenkatesh Pallipadiconfig ARCH_USES_PG_UNCACHED 179046cf98cdSVenkatesh Pallipadi def_bool y 179146cf98cdSVenkatesh Pallipadi depends on X86_PAT 179246cf98cdSVenkatesh Pallipadi 1793b971880fSBabu Mogerconfig X86_UMIP 1794796ebc81SRicardo Neri def_bool y 1795b971880fSBabu Moger prompt "User Mode Instruction Prevention" if EXPERT 1796a7f7f624SMasahiro Yamada help 1797b971880fSBabu Moger User Mode Instruction Prevention (UMIP) is a security feature in 1798b971880fSBabu Moger some x86 processors. If enabled, a general protection fault is 1799b971880fSBabu Moger issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1800b971880fSBabu Moger executed in user mode. These instructions unnecessarily expose 1801b971880fSBabu Moger information about the hardware state. 1802796ebc81SRicardo Neri 1803796ebc81SRicardo Neri The vast majority of applications do not use these instructions. 1804796ebc81SRicardo Neri For the very few that do, software emulation is provided in 1805796ebc81SRicardo Neri specific cases in protected and virtual-8086 modes. Emulated 1806796ebc81SRicardo Neri results are dummy. 1807aa35f896SRicardo Neri 1808156ff4a5SPeter Zijlstraconfig CC_HAS_IBT 1809156ff4a5SPeter Zijlstra # GCC >= 9 and binutils >= 2.29 1810156ff4a5SPeter Zijlstra # Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654 1811156ff4a5SPeter Zijlstra # Clang/LLVM >= 14 1812262448f3SNathan Chancellor # https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f 1813262448f3SNathan Chancellor # https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332 1814156ff4a5SPeter Zijlstra def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \ 1815262448f3SNathan Chancellor (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \ 1816156ff4a5SPeter Zijlstra $(as-instr,endbr64) 1817156ff4a5SPeter Zijlstra 181818e66b69SRick Edgecombeconfig X86_CET 181918e66b69SRick Edgecombe def_bool n 182018e66b69SRick Edgecombe help 182118e66b69SRick Edgecombe CET features configured (Shadow stack or IBT) 182218e66b69SRick Edgecombe 1823156ff4a5SPeter Zijlstraconfig X86_KERNEL_IBT 1824156ff4a5SPeter Zijlstra prompt "Indirect Branch Tracking" 18254fd5f70cSKees Cook def_bool y 182603f16cd0SJosh Poimboeuf depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL 1827f6a2c2b2SNathan Chancellor # https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f 1828f6a2c2b2SNathan Chancellor depends on !LD_IS_LLD || LLD_VERSION >= 140000 182903f16cd0SJosh Poimboeuf select OBJTOOL 183018e66b69SRick Edgecombe select X86_CET 1831156ff4a5SPeter Zijlstra help 1832156ff4a5SPeter Zijlstra Build the kernel with support for Indirect Branch Tracking, a 1833156ff4a5SPeter Zijlstra hardware support course-grain forward-edge Control Flow Integrity 1834156ff4a5SPeter Zijlstra protection. It enforces that all indirect calls must land on 1835156ff4a5SPeter Zijlstra an ENDBR instruction, as such, the compiler will instrument the 1836156ff4a5SPeter Zijlstra code with them to make this happen. 1837156ff4a5SPeter Zijlstra 1838ed53a0d9SPeter Zijlstra In addition to building the kernel with IBT, seal all functions that 18394cdfc11bSNur Hussein are not indirect call targets, avoiding them ever becoming one. 1840ed53a0d9SPeter Zijlstra 1841ed53a0d9SPeter Zijlstra This requires LTO like objtool runs and will slow down the build. It 1842ed53a0d9SPeter Zijlstra does significantly reduce the number of ENDBR instructions in the 1843ed53a0d9SPeter Zijlstra kernel image. 1844ed53a0d9SPeter Zijlstra 184535e97790SDave Hansenconfig X86_INTEL_MEMORY_PROTECTION_KEYS 184638f3e775SBabu Moger prompt "Memory Protection Keys" 184735e97790SDave Hansen def_bool y 1848284244a9SDave Hansen # Note: only available in 64-bit mode 184938f3e775SBabu Moger depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 185052c8e601SIngo Molnar select ARCH_USES_HIGH_VMA_FLAGS 185152c8e601SIngo Molnar select ARCH_HAS_PKEYS 1852a7f7f624SMasahiro Yamada help 1853284244a9SDave Hansen Memory Protection Keys provides a mechanism for enforcing 1854284244a9SDave Hansen page-based protections, but without requiring modification of the 1855284244a9SDave Hansen page tables when an application changes protection domains. 1856284244a9SDave Hansen 18571eecbcdcSMauro Carvalho Chehab For details, see Documentation/core-api/protection-keys.rst 1858284244a9SDave Hansen 1859284244a9SDave Hansen If unsure, say y. 186035e97790SDave Hansen 1861db616173SMichal Hockochoice 1862db616173SMichal Hocko prompt "TSX enable mode" 1863db616173SMichal Hocko depends on CPU_SUP_INTEL 1864db616173SMichal Hocko default X86_INTEL_TSX_MODE_OFF 1865db616173SMichal Hocko help 1866db616173SMichal Hocko Intel's TSX (Transactional Synchronization Extensions) feature 1867db616173SMichal Hocko allows to optimize locking protocols through lock elision which 1868db616173SMichal Hocko can lead to a noticeable performance boost. 1869db616173SMichal Hocko 1870db616173SMichal Hocko On the other hand it has been shown that TSX can be exploited 1871db616173SMichal Hocko to form side channel attacks (e.g. TAA) and chances are there 1872db616173SMichal Hocko will be more of those attacks discovered in the future. 1873db616173SMichal Hocko 1874db616173SMichal Hocko Therefore TSX is not enabled by default (aka tsx=off). An admin 1875db616173SMichal Hocko might override this decision by tsx=on the command line parameter. 1876db616173SMichal Hocko Even with TSX enabled, the kernel will attempt to enable the best 1877db616173SMichal Hocko possible TAA mitigation setting depending on the microcode available 1878db616173SMichal Hocko for the particular machine. 1879db616173SMichal Hocko 1880db616173SMichal Hocko This option allows to set the default tsx mode between tsx=on, =off 1881db616173SMichal Hocko and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1882db616173SMichal Hocko details. 1883db616173SMichal Hocko 1884db616173SMichal Hocko Say off if not sure, auto if TSX is in use but it should be used on safe 1885db616173SMichal Hocko platforms or on if TSX is in use and the security aspect of tsx is not 1886db616173SMichal Hocko relevant. 1887db616173SMichal Hocko 1888db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_OFF 1889db616173SMichal Hocko bool "off" 1890db616173SMichal Hocko help 1891db616173SMichal Hocko TSX is disabled if possible - equals to tsx=off command line parameter. 1892db616173SMichal Hocko 1893db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_ON 1894db616173SMichal Hocko bool "on" 1895db616173SMichal Hocko help 1896db616173SMichal Hocko TSX is always enabled on TSX capable HW - equals the tsx=on command 1897db616173SMichal Hocko line parameter. 1898db616173SMichal Hocko 1899db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_AUTO 1900db616173SMichal Hocko bool "auto" 1901db616173SMichal Hocko help 1902db616173SMichal Hocko TSX is enabled on TSX capable HW that is believed to be safe against 1903db616173SMichal Hocko side channel attacks- equals the tsx=auto command line parameter. 1904db616173SMichal Hockoendchoice 1905db616173SMichal Hocko 1906e7e05452SSean Christophersonconfig X86_SGX 1907e7e05452SSean Christopherson bool "Software Guard eXtensions (SGX)" 1908b8d1d163SDaniel Sneddon depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC 1909e7e05452SSean Christopherson depends on CRYPTO=y 1910e7e05452SSean Christopherson depends on CRYPTO_SHA256=y 1911e7e05452SSean Christopherson select MMU_NOTIFIER 1912901ddbb9SJarkko Sakkinen select NUMA_KEEP_MEMINFO if NUMA 191340e0e784STony Luck select XARRAY_MULTI 1914e7e05452SSean Christopherson help 1915e7e05452SSean Christopherson Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1916e7e05452SSean Christopherson that can be used by applications to set aside private regions of code 1917e7e05452SSean Christopherson and data, referred to as enclaves. An enclave's private memory can 1918e7e05452SSean Christopherson only be accessed by code running within the enclave. Accesses from 1919e7e05452SSean Christopherson outside the enclave, including other enclaves, are disallowed by 1920e7e05452SSean Christopherson hardware. 1921e7e05452SSean Christopherson 1922e7e05452SSean Christopherson If unsure, say N. 1923e7e05452SSean Christopherson 192418e66b69SRick Edgecombeconfig X86_USER_SHADOW_STACK 192518e66b69SRick Edgecombe bool "X86 userspace shadow stack" 192618e66b69SRick Edgecombe depends on AS_WRUSS 192718e66b69SRick Edgecombe depends on X86_64 192818e66b69SRick Edgecombe select ARCH_USES_HIGH_VMA_FLAGS 192918e66b69SRick Edgecombe select X86_CET 193018e66b69SRick Edgecombe help 193118e66b69SRick Edgecombe Shadow stack protection is a hardware feature that detects function 193218e66b69SRick Edgecombe return address corruption. This helps mitigate ROP attacks. 193318e66b69SRick Edgecombe Applications must be enabled to use it, and old userspace does not 193418e66b69SRick Edgecombe get protection "for free". 193518e66b69SRick Edgecombe 193618e66b69SRick Edgecombe CPUs supporting shadow stacks were first released in 2020. 193718e66b69SRick Edgecombe 193854acee60SDave Hansen See Documentation/arch/x86/shstk.rst for more information. 193918e66b69SRick Edgecombe 194018e66b69SRick Edgecombe If unsure, say N. 194118e66b69SRick Edgecombe 1942506f1d07SSam Ravnborgconfig EFI 19439ba16087SJan Beulich bool "EFI runtime service support" 19445b83683fSHuang, Ying depends on ACPI 1945f6ce5002SSergey Vlasov select UCS2_STRING 1946022ee6c5SArd Biesheuvel select EFI_RUNTIME_WRAPPERS 19471ff2fc02STom Lendacky select ARCH_USE_MEMREMAP_PROT 1948a7f7f624SMasahiro Yamada help 19498b2cb7a8SHuang, Ying This enables the kernel to use EFI runtime services that are 1950506f1d07SSam Ravnborg available (such as the EFI variable services). 1951506f1d07SSam Ravnborg 19528b2cb7a8SHuang, Ying This option is only useful on systems that have EFI firmware. 19538b2cb7a8SHuang, Ying In addition, you should use the latest ELILO loader available 19548b2cb7a8SHuang, Ying at <http://elilo.sourceforge.net> in order to take advantage 19558b2cb7a8SHuang, Ying of EFI runtime services. However, even with this option, the 19568b2cb7a8SHuang, Ying resultant kernel should continue to boot on existing non-EFI 19578b2cb7a8SHuang, Ying platforms. 1958506f1d07SSam Ravnborg 1959291f3632SMatt Flemingconfig EFI_STUB 1960291f3632SMatt Fleming bool "EFI stub support" 1961c6dbd3e5SPeter Zijlstra depends on EFI 19627b2a583aSMatt Fleming select RELOCATABLE 1963a7f7f624SMasahiro Yamada help 1964291f3632SMatt Fleming This kernel feature allows a bzImage to be loaded directly 1965291f3632SMatt Fleming by EFI firmware without the use of a bootloader. 1966291f3632SMatt Fleming 19674f4cfa6cSMauro Carvalho Chehab See Documentation/admin-guide/efi-stub.rst for more information. 19680c759662SMatt Fleming 1969cc3fdda2SArd Biesheuvelconfig EFI_HANDOVER_PROTOCOL 1970cc3fdda2SArd Biesheuvel bool "EFI handover protocol (DEPRECATED)" 1971cc3fdda2SArd Biesheuvel depends on EFI_STUB 1972cc3fdda2SArd Biesheuvel default y 1973cc3fdda2SArd Biesheuvel help 1974cc3fdda2SArd Biesheuvel Select this in order to include support for the deprecated EFI 1975cc3fdda2SArd Biesheuvel handover protocol, which defines alternative entry points into the 1976cc3fdda2SArd Biesheuvel EFI stub. This is a practice that has no basis in the UEFI 1977cc3fdda2SArd Biesheuvel specification, and requires a priori knowledge on the part of the 1978cc3fdda2SArd Biesheuvel bootloader about Linux/x86 specific ways of passing the command line 1979cc3fdda2SArd Biesheuvel and initrd, and where in memory those assets may be loaded. 1980cc3fdda2SArd Biesheuvel 1981cc3fdda2SArd Biesheuvel If in doubt, say Y. Even though the corresponding support is not 1982cc3fdda2SArd Biesheuvel present in upstream GRUB or other bootloaders, most distros build 1983cc3fdda2SArd Biesheuvel GRUB with numerous downstream patches applied, and may rely on the 1984cc3fdda2SArd Biesheuvel handover protocol as as result. 1985cc3fdda2SArd Biesheuvel 19867d453eeeSMatt Flemingconfig EFI_MIXED 19877d453eeeSMatt Fleming bool "EFI mixed-mode support" 19887d453eeeSMatt Fleming depends on EFI_STUB && X86_64 1989a7f7f624SMasahiro Yamada help 19907d453eeeSMatt Fleming Enabling this feature allows a 64-bit kernel to be booted 19917d453eeeSMatt Fleming on a 32-bit firmware, provided that your CPU supports 64-bit 19927d453eeeSMatt Fleming mode. 19937d453eeeSMatt Fleming 19947d453eeeSMatt Fleming Note that it is not possible to boot a mixed-mode enabled 19957d453eeeSMatt Fleming kernel via the EFI boot stub - a bootloader that supports 19967d453eeeSMatt Fleming the EFI handover protocol must be used. 19977d453eeeSMatt Fleming 19987d453eeeSMatt Fleming If unsure, say N. 19997d453eeeSMatt Fleming 20004059ba65SArd Biesheuvelconfig EFI_FAKE_MEMMAP 20014059ba65SArd Biesheuvel bool "Enable EFI fake memory map" 20024059ba65SArd Biesheuvel depends on EFI 20034059ba65SArd Biesheuvel help 20044059ba65SArd Biesheuvel Saying Y here will enable "efi_fake_mem" boot option. By specifying 20054059ba65SArd Biesheuvel this parameter, you can add arbitrary attribute to specific memory 20064059ba65SArd Biesheuvel range by updating original (firmware provided) EFI memmap. This is 20074059ba65SArd Biesheuvel useful for debugging of EFI memmap related feature, e.g., Address 20084059ba65SArd Biesheuvel Range Mirroring feature. 20094059ba65SArd Biesheuvel 20104059ba65SArd Biesheuvelconfig EFI_MAX_FAKE_MEM 20114059ba65SArd Biesheuvel int "maximum allowable number of ranges in efi_fake_mem boot option" 20124059ba65SArd Biesheuvel depends on EFI_FAKE_MEMMAP 20134059ba65SArd Biesheuvel range 1 128 20144059ba65SArd Biesheuvel default 8 20154059ba65SArd Biesheuvel help 20164059ba65SArd Biesheuvel Maximum allowable number of ranges in efi_fake_mem boot option. 20174059ba65SArd Biesheuvel Ranges can be set up to this value using comma-separated list. 20184059ba65SArd Biesheuvel The default value is 8. 20194059ba65SArd Biesheuvel 20201fff234dSArd Biesheuvelconfig EFI_RUNTIME_MAP 20211fff234dSArd Biesheuvel bool "Export EFI runtime maps to sysfs" if EXPERT 20221fff234dSArd Biesheuvel depends on EFI 20231fff234dSArd Biesheuvel default KEXEC_CORE 20241fff234dSArd Biesheuvel help 20251fff234dSArd Biesheuvel Export EFI runtime memory regions to /sys/firmware/efi/runtime-map. 20261fff234dSArd Biesheuvel That memory map is required by the 2nd kernel to set up EFI virtual 20271fff234dSArd Biesheuvel mappings after kexec, but can also be used for debugging purposes. 20281fff234dSArd Biesheuvel 20291fff234dSArd Biesheuvel See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map. 20301fff234dSArd Biesheuvel 20318636a1f9SMasahiro Yamadasource "kernel/Kconfig.hz" 2032506f1d07SSam Ravnborg 20336af51380SEric DeVolderconfig ARCH_SUPPORTS_KEXEC 20346af51380SEric DeVolder def_bool y 2035506f1d07SSam Ravnborg 20366af51380SEric DeVolderconfig ARCH_SUPPORTS_KEXEC_FILE 20376af51380SEric DeVolder def_bool X86_64 && CRYPTO && CRYPTO_SHA256 2038506f1d07SSam Ravnborg 20396af51380SEric DeVolderconfig ARCH_SELECTS_KEXEC_FILE 20406af51380SEric DeVolder def_bool y 20416af51380SEric DeVolder depends on KEXEC_FILE 2042b69a2afdSJonathan McDowell select HAVE_IMA_KEXEC if IMA 204374ca317cSVivek Goyal 2044e6265fe7SEric DeVolderconfig ARCH_SUPPORTS_KEXEC_PURGATORY 2045b799a09fSAKASHI Takahiro def_bool KEXEC_FILE 2046b799a09fSAKASHI Takahiro 20476af51380SEric DeVolderconfig ARCH_SUPPORTS_KEXEC_SIG 20486af51380SEric DeVolder def_bool y 204999d5cadfSJiri Bohac 20506af51380SEric DeVolderconfig ARCH_SUPPORTS_KEXEC_SIG_FORCE 20516af51380SEric DeVolder def_bool y 205299d5cadfSJiri Bohac 20536af51380SEric DeVolderconfig ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG 20546af51380SEric DeVolder def_bool y 205599d5cadfSJiri Bohac 20566af51380SEric DeVolderconfig ARCH_SUPPORTS_KEXEC_JUMP 20576af51380SEric DeVolder def_bool y 20588e7d8381SVivek Goyal 20596af51380SEric DeVolderconfig ARCH_SUPPORTS_CRASH_DUMP 20606af51380SEric DeVolder def_bool X86_64 || (X86_32 && HIGHMEM) 20618e7d8381SVivek Goyal 2062ea53ad9cSEric DeVolderconfig ARCH_SUPPORTS_CRASH_HOTPLUG 2063ea53ad9cSEric DeVolder def_bool y 20643ab83521SHuang Ying 2065506f1d07SSam Ravnborgconfig PHYSICAL_START 20666a108a14SDavid Rientjes hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2067ceefccc9SH. Peter Anvin default "0x1000000" 2068a7f7f624SMasahiro Yamada help 2069506f1d07SSam Ravnborg This gives the physical address where the kernel is loaded. 2070506f1d07SSam Ravnborg 2071506f1d07SSam Ravnborg If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2072506f1d07SSam Ravnborg bzImage will decompress itself to above physical address and 2073506f1d07SSam Ravnborg run from there. Otherwise, bzImage will run from the address where 2074506f1d07SSam Ravnborg it has been loaded by the boot loader and will ignore above physical 2075506f1d07SSam Ravnborg address. 2076506f1d07SSam Ravnborg 2077506f1d07SSam Ravnborg In normal kdump cases one does not have to set/change this option 2078506f1d07SSam Ravnborg as now bzImage can be compiled as a completely relocatable image 2079506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2080506f1d07SSam Ravnborg address. This option is mainly useful for the folks who don't want 2081506f1d07SSam Ravnborg to use a bzImage for capturing the crash dump and want to use a 2082506f1d07SSam Ravnborg vmlinux instead. vmlinux is not relocatable hence a kernel needs 2083506f1d07SSam Ravnborg to be specifically compiled to run from a specific memory area 2084506f1d07SSam Ravnborg (normally a reserved region) and this option comes handy. 2085506f1d07SSam Ravnborg 2086ceefccc9SH. Peter Anvin So if you are using bzImage for capturing the crash dump, 2087ceefccc9SH. Peter Anvin leave the value here unchanged to 0x1000000 and set 2088ceefccc9SH. Peter Anvin CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2089ceefccc9SH. Peter Anvin for capturing the crash dump change this value to start of 2090ceefccc9SH. Peter Anvin the reserved region. In other words, it can be set based on 2091ceefccc9SH. Peter Anvin the "X" value as specified in the "crashkernel=YM@XM" 2092ceefccc9SH. Peter Anvin command line boot parameter passed to the panic-ed 2093330d4810SMauro Carvalho Chehab kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2094ceefccc9SH. Peter Anvin for more details about crash dumps. 2095506f1d07SSam Ravnborg 2096506f1d07SSam Ravnborg Usage of bzImage for capturing the crash dump is recommended as 2097506f1d07SSam Ravnborg one does not have to build two kernels. Same kernel can be used 2098506f1d07SSam Ravnborg as production kernel and capture kernel. Above option should have 2099506f1d07SSam Ravnborg gone away after relocatable bzImage support is introduced. But it 2100506f1d07SSam Ravnborg is present because there are users out there who continue to use 2101506f1d07SSam Ravnborg vmlinux for dump capture. This option should go away down the 2102506f1d07SSam Ravnborg line. 2103506f1d07SSam Ravnborg 2104506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2105506f1d07SSam Ravnborg 2106506f1d07SSam Ravnborgconfig RELOCATABLE 210726717808SH. Peter Anvin bool "Build a relocatable kernel" 210826717808SH. Peter Anvin default y 2109a7f7f624SMasahiro Yamada help 2110506f1d07SSam Ravnborg This builds a kernel image that retains relocation information 2111506f1d07SSam Ravnborg so it can be loaded someplace besides the default 1MB. 2112506f1d07SSam Ravnborg The relocations tend to make the kernel binary about 10% larger, 2113506f1d07SSam Ravnborg but are discarded at runtime. 2114506f1d07SSam Ravnborg 2115506f1d07SSam Ravnborg One use is for the kexec on panic case where the recovery kernel 2116506f1d07SSam Ravnborg must live at a different physical address than the primary 2117506f1d07SSam Ravnborg kernel. 2118506f1d07SSam Ravnborg 2119506f1d07SSam Ravnborg Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2120506f1d07SSam Ravnborg it has been loaded at and the compile time physical address 21218ab3820fSKees Cook (CONFIG_PHYSICAL_START) is used as the minimum location. 2122506f1d07SSam Ravnborg 21238ab3820fSKees Cookconfig RANDOMIZE_BASE 2124e8581e3dSBaoquan He bool "Randomize the address of the kernel image (KASLR)" 21258ab3820fSKees Cook depends on RELOCATABLE 21266807c846SIngo Molnar default y 2127a7f7f624SMasahiro Yamada help 2128e8581e3dSBaoquan He In support of Kernel Address Space Layout Randomization (KASLR), 2129e8581e3dSBaoquan He this randomizes the physical address at which the kernel image 2130e8581e3dSBaoquan He is decompressed and the virtual address where the kernel 2131e8581e3dSBaoquan He image is mapped, as a security feature that deters exploit 2132e8581e3dSBaoquan He attempts relying on knowledge of the location of kernel 2133e8581e3dSBaoquan He code internals. 2134e8581e3dSBaoquan He 2135ed9f007eSKees Cook On 64-bit, the kernel physical and virtual addresses are 2136ed9f007eSKees Cook randomized separately. The physical address will be anywhere 2137ed9f007eSKees Cook between 16MB and the top of physical memory (up to 64TB). The 2138ed9f007eSKees Cook virtual address will be randomized from 16MB up to 1GB (9 bits 2139ed9f007eSKees Cook of entropy). Note that this also reduces the memory space 2140ed9f007eSKees Cook available to kernel modules from 1.5GB to 1GB. 2141ed9f007eSKees Cook 2142ed9f007eSKees Cook On 32-bit, the kernel physical and virtual addresses are 2143ed9f007eSKees Cook randomized together. They will be randomized from 16MB up to 2144ed9f007eSKees Cook 512MB (8 bits of entropy). 21458ab3820fSKees Cook 2146a653f356SKees Cook Entropy is generated using the RDRAND instruction if it is 2147e8581e3dSBaoquan He supported. If RDTSC is supported, its value is mixed into 2148e8581e3dSBaoquan He the entropy pool as well. If neither RDRAND nor RDTSC are 2149ed9f007eSKees Cook supported, then entropy is read from the i8254 timer. The 2150ed9f007eSKees Cook usable entropy is limited by the kernel being built using 2151ed9f007eSKees Cook 2GB addressing, and that PHYSICAL_ALIGN must be at a 2152ed9f007eSKees Cook minimum of 2MB. As a result, only 10 bits of entropy are 2153ed9f007eSKees Cook theoretically possible, but the implementations are further 2154ed9f007eSKees Cook limited due to memory layouts. 2155e8581e3dSBaoquan He 21566807c846SIngo Molnar If unsure, say Y. 2157da2b6fb9SKees Cook 21588ab3820fSKees Cook# Relocation on x86 needs some additional build support 2159845adf72SH. Peter Anvinconfig X86_NEED_RELOCS 2160845adf72SH. Peter Anvin def_bool y 21618ab3820fSKees Cook depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2162845adf72SH. Peter Anvin 2163506f1d07SSam Ravnborgconfig PHYSICAL_ALIGN 2164a0215061SKees Cook hex "Alignment value to which kernel should be aligned" 21658ab3820fSKees Cook default "0x200000" 2166a0215061SKees Cook range 0x2000 0x1000000 if X86_32 2167a0215061SKees Cook range 0x200000 0x1000000 if X86_64 2168a7f7f624SMasahiro Yamada help 2169506f1d07SSam Ravnborg This value puts the alignment restrictions on physical address 2170506f1d07SSam Ravnborg where kernel is loaded and run from. Kernel is compiled for an 2171506f1d07SSam Ravnborg address which meets above alignment restriction. 2172506f1d07SSam Ravnborg 2173506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2174506f1d07SSam Ravnborg CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2175506f1d07SSam Ravnborg address aligned to above value and run from there. 2176506f1d07SSam Ravnborg 2177506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2178506f1d07SSam Ravnborg CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2179506f1d07SSam Ravnborg load address and decompress itself to the address it has been 2180506f1d07SSam Ravnborg compiled for and run from there. The address for which kernel is 2181506f1d07SSam Ravnborg compiled already meets above alignment restrictions. Hence the 2182506f1d07SSam Ravnborg end result is that kernel runs from a physical address meeting 2183506f1d07SSam Ravnborg above alignment restrictions. 2184506f1d07SSam Ravnborg 2185a0215061SKees Cook On 32-bit this value must be a multiple of 0x2000. On 64-bit 2186a0215061SKees Cook this value must be a multiple of 0x200000. 2187a0215061SKees Cook 2188506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2189506f1d07SSam Ravnborg 2190eedb92abSKirill A. Shutemovconfig DYNAMIC_MEMORY_LAYOUT 2191eedb92abSKirill A. Shutemov bool 2192a7f7f624SMasahiro Yamada help 2193eedb92abSKirill A. Shutemov This option makes base addresses of vmalloc and vmemmap as well as 2194eedb92abSKirill A. Shutemov __PAGE_OFFSET movable during boot. 2195eedb92abSKirill A. Shutemov 21960483e1faSThomas Garnierconfig RANDOMIZE_MEMORY 21970483e1faSThomas Garnier bool "Randomize the kernel memory sections" 21980483e1faSThomas Garnier depends on X86_64 21990483e1faSThomas Garnier depends on RANDOMIZE_BASE 2200eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 22010483e1faSThomas Garnier default RANDOMIZE_BASE 2202a7f7f624SMasahiro Yamada help 22030483e1faSThomas Garnier Randomizes the base virtual address of kernel memory sections 22040483e1faSThomas Garnier (physical memory mapping, vmalloc & vmemmap). This security feature 22050483e1faSThomas Garnier makes exploits relying on predictable memory locations less reliable. 22060483e1faSThomas Garnier 22070483e1faSThomas Garnier The order of allocations remains unchanged. Entropy is generated in 22080483e1faSThomas Garnier the same way as RANDOMIZE_BASE. Current implementation in the optimal 22090483e1faSThomas Garnier configuration have in average 30,000 different possible virtual 22100483e1faSThomas Garnier addresses for each memory section. 22110483e1faSThomas Garnier 22126807c846SIngo Molnar If unsure, say Y. 22130483e1faSThomas Garnier 221490397a41SThomas Garnierconfig RANDOMIZE_MEMORY_PHYSICAL_PADDING 221590397a41SThomas Garnier hex "Physical memory mapping padding" if EXPERT 221690397a41SThomas Garnier depends on RANDOMIZE_MEMORY 221790397a41SThomas Garnier default "0xa" if MEMORY_HOTPLUG 221890397a41SThomas Garnier default "0x0" 221990397a41SThomas Garnier range 0x1 0x40 if MEMORY_HOTPLUG 222090397a41SThomas Garnier range 0x0 0x40 2221a7f7f624SMasahiro Yamada help 222290397a41SThomas Garnier Define the padding in terabytes added to the existing physical 222390397a41SThomas Garnier memory size during kernel memory randomization. It is useful 222490397a41SThomas Garnier for memory hotplug support but reduces the entropy available for 222590397a41SThomas Garnier address randomization. 222690397a41SThomas Garnier 222790397a41SThomas Garnier If unsure, leave at the default value. 222890397a41SThomas Garnier 22296449dcb0SKirill A. Shutemovconfig ADDRESS_MASKING 22306449dcb0SKirill A. Shutemov bool "Linear Address Masking support" 22316449dcb0SKirill A. Shutemov depends on X86_64 22326449dcb0SKirill A. Shutemov help 22336449dcb0SKirill A. Shutemov Linear Address Masking (LAM) modifies the checking that is applied 22346449dcb0SKirill A. Shutemov to 64-bit linear addresses, allowing software to use of the 22356449dcb0SKirill A. Shutemov untranslated address bits for metadata. 22366449dcb0SKirill A. Shutemov 22376449dcb0SKirill A. Shutemov The capability can be used for efficient address sanitizers (ASAN) 22386449dcb0SKirill A. Shutemov implementation and for optimizations in JITs. 22396449dcb0SKirill A. Shutemov 2240506f1d07SSam Ravnborgconfig HOTPLUG_CPU 2241bebd024eSThomas Gleixner def_bool y 224240b31360SStephen Rothwell depends on SMP 2243506f1d07SSam Ravnborg 2244506f1d07SSam Ravnborgconfig COMPAT_VDSO 2245b0b49f26SAndy Lutomirski def_bool n 2246b0b49f26SAndy Lutomirski prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2247953fee1dSIngo Molnar depends on COMPAT_32 2248a7f7f624SMasahiro Yamada help 2249b0b49f26SAndy Lutomirski Certain buggy versions of glibc will crash if they are 2250b0b49f26SAndy Lutomirski presented with a 32-bit vDSO that is not mapped at the address 2251b0b49f26SAndy Lutomirski indicated in its segment table. 2252e84446deSRandy Dunlap 2253b0b49f26SAndy Lutomirski The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2254b0b49f26SAndy Lutomirski and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2255b0b49f26SAndy Lutomirski 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2256b0b49f26SAndy Lutomirski the only released version with the bug, but OpenSUSE 9 2257b0b49f26SAndy Lutomirski contains a buggy "glibc 2.3.2". 2258506f1d07SSam Ravnborg 2259b0b49f26SAndy Lutomirski The symptom of the bug is that everything crashes on startup, saying: 2260b0b49f26SAndy Lutomirski dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2261b0b49f26SAndy Lutomirski 2262b0b49f26SAndy Lutomirski Saying Y here changes the default value of the vdso32 boot 2263b0b49f26SAndy Lutomirski option from 1 to 0, which turns off the 32-bit vDSO entirely. 2264b0b49f26SAndy Lutomirski This works around the glibc bug but hurts performance. 2265b0b49f26SAndy Lutomirski 2266b0b49f26SAndy Lutomirski If unsure, say N: if you are compiling your own kernel, you 2267b0b49f26SAndy Lutomirski are unlikely to be using a buggy version of glibc. 2268506f1d07SSam Ravnborg 22693dc33bd3SKees Cookchoice 22703dc33bd3SKees Cook prompt "vsyscall table for legacy applications" 22713dc33bd3SKees Cook depends on X86_64 2272625b7b7fSAndy Lutomirski default LEGACY_VSYSCALL_XONLY 22733dc33bd3SKees Cook help 22743dc33bd3SKees Cook Legacy user code that does not know how to find the vDSO expects 22753dc33bd3SKees Cook to be able to issue three syscalls by calling fixed addresses in 22763dc33bd3SKees Cook kernel space. Since this location is not randomized with ASLR, 22773dc33bd3SKees Cook it can be used to assist security vulnerability exploitation. 22783dc33bd3SKees Cook 22793dc33bd3SKees Cook This setting can be changed at boot time via the kernel command 2280bf00745eSAndy Lutomirski line parameter vsyscall=[emulate|xonly|none]. Emulate mode 2281bf00745eSAndy Lutomirski is deprecated and can only be enabled using the kernel command 2282bf00745eSAndy Lutomirski line. 22833dc33bd3SKees Cook 22843dc33bd3SKees Cook On a system with recent enough glibc (2.14 or newer) and no 22853dc33bd3SKees Cook static binaries, you can say None without a performance penalty 22863dc33bd3SKees Cook to improve security. 22873dc33bd3SKees Cook 2288bd49e16eSAndy Lutomirski If unsure, select "Emulate execution only". 22893dc33bd3SKees Cook 2290bd49e16eSAndy Lutomirski config LEGACY_VSYSCALL_XONLY 2291bd49e16eSAndy Lutomirski bool "Emulate execution only" 2292bd49e16eSAndy Lutomirski help 2293bd49e16eSAndy Lutomirski The kernel traps and emulates calls into the fixed vsyscall 2294bd49e16eSAndy Lutomirski address mapping and does not allow reads. This 2295bd49e16eSAndy Lutomirski configuration is recommended when userspace might use the 2296bd49e16eSAndy Lutomirski legacy vsyscall area but support for legacy binary 2297bd49e16eSAndy Lutomirski instrumentation of legacy code is not needed. It mitigates 2298bd49e16eSAndy Lutomirski certain uses of the vsyscall area as an ASLR-bypassing 2299bd49e16eSAndy Lutomirski buffer. 23003dc33bd3SKees Cook 23013dc33bd3SKees Cook config LEGACY_VSYSCALL_NONE 23023dc33bd3SKees Cook bool "None" 23033dc33bd3SKees Cook help 23043dc33bd3SKees Cook There will be no vsyscall mapping at all. This will 23053dc33bd3SKees Cook eliminate any risk of ASLR bypass due to the vsyscall 23063dc33bd3SKees Cook fixed address mapping. Attempts to use the vsyscalls 23073dc33bd3SKees Cook will be reported to dmesg, so that either old or 23083dc33bd3SKees Cook malicious userspace programs can be identified. 23093dc33bd3SKees Cook 23103dc33bd3SKees Cookendchoice 23113dc33bd3SKees Cook 2312516cbf37STim Birdconfig CMDLINE_BOOL 2313516cbf37STim Bird bool "Built-in kernel command line" 2314a7f7f624SMasahiro Yamada help 2315516cbf37STim Bird Allow for specifying boot arguments to the kernel at 2316516cbf37STim Bird build time. On some systems (e.g. embedded ones), it is 2317516cbf37STim Bird necessary or convenient to provide some or all of the 2318516cbf37STim Bird kernel boot arguments with the kernel itself (that is, 2319516cbf37STim Bird to not rely on the boot loader to provide them.) 2320516cbf37STim Bird 2321516cbf37STim Bird To compile command line arguments into the kernel, 2322516cbf37STim Bird set this option to 'Y', then fill in the 232369711ca1SSébastien Hinderer boot arguments in CONFIG_CMDLINE. 2324516cbf37STim Bird 2325516cbf37STim Bird Systems with fully functional boot loaders (i.e. non-embedded) 2326516cbf37STim Bird should leave this option set to 'N'. 2327516cbf37STim Bird 2328516cbf37STim Birdconfig CMDLINE 2329516cbf37STim Bird string "Built-in kernel command string" 2330516cbf37STim Bird depends on CMDLINE_BOOL 2331516cbf37STim Bird default "" 2332a7f7f624SMasahiro Yamada help 2333516cbf37STim Bird Enter arguments here that should be compiled into the kernel 2334516cbf37STim Bird image and used at boot time. If the boot loader provides a 2335516cbf37STim Bird command line at boot time, it is appended to this string to 2336516cbf37STim Bird form the full kernel command line, when the system boots. 2337516cbf37STim Bird 2338516cbf37STim Bird However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2339516cbf37STim Bird change this behavior. 2340516cbf37STim Bird 2341516cbf37STim Bird In most cases, the command line (whether built-in or provided 2342516cbf37STim Bird by the boot loader) should specify the device for the root 2343516cbf37STim Bird file system. 2344516cbf37STim Bird 2345516cbf37STim Birdconfig CMDLINE_OVERRIDE 2346516cbf37STim Bird bool "Built-in command line overrides boot loader arguments" 2347645e6466SAnders Roxell depends on CMDLINE_BOOL && CMDLINE != "" 2348a7f7f624SMasahiro Yamada help 2349516cbf37STim Bird Set this option to 'Y' to have the kernel ignore the boot loader 2350516cbf37STim Bird command line, and use ONLY the built-in command line. 2351516cbf37STim Bird 2352516cbf37STim Bird This is used to work around broken boot loaders. This should 2353516cbf37STim Bird be set to 'N' under normal conditions. 2354516cbf37STim Bird 2355a5b9e5a2SAndy Lutomirskiconfig MODIFY_LDT_SYSCALL 2356a5b9e5a2SAndy Lutomirski bool "Enable the LDT (local descriptor table)" if EXPERT 2357a5b9e5a2SAndy Lutomirski default y 2358a7f7f624SMasahiro Yamada help 2359a5b9e5a2SAndy Lutomirski Linux can allow user programs to install a per-process x86 2360a5b9e5a2SAndy Lutomirski Local Descriptor Table (LDT) using the modify_ldt(2) system 2361a5b9e5a2SAndy Lutomirski call. This is required to run 16-bit or segmented code such as 2362a5b9e5a2SAndy Lutomirski DOSEMU or some Wine programs. It is also used by some very old 2363a5b9e5a2SAndy Lutomirski threading libraries. 2364a5b9e5a2SAndy Lutomirski 2365a5b9e5a2SAndy Lutomirski Enabling this feature adds a small amount of overhead to 2366a5b9e5a2SAndy Lutomirski context switches and increases the low-level kernel attack 2367a5b9e5a2SAndy Lutomirski surface. Disabling it removes the modify_ldt(2) system call. 2368a5b9e5a2SAndy Lutomirski 2369a5b9e5a2SAndy Lutomirski Saying 'N' here may make sense for embedded or server kernels. 2370a5b9e5a2SAndy Lutomirski 23713aac3ebeSThomas Gleixnerconfig STRICT_SIGALTSTACK_SIZE 23723aac3ebeSThomas Gleixner bool "Enforce strict size checking for sigaltstack" 23733aac3ebeSThomas Gleixner depends on DYNAMIC_SIGFRAME 23743aac3ebeSThomas Gleixner help 23753aac3ebeSThomas Gleixner For historical reasons MINSIGSTKSZ is a constant which became 23763aac3ebeSThomas Gleixner already too small with AVX512 support. Add a mechanism to 23773aac3ebeSThomas Gleixner enforce strict checking of the sigaltstack size against the 23783aac3ebeSThomas Gleixner real size of the FPU frame. This option enables the check 23793aac3ebeSThomas Gleixner by default. It can also be controlled via the kernel command 23803aac3ebeSThomas Gleixner line option 'strict_sas_size' independent of this config 23813aac3ebeSThomas Gleixner switch. Enabling it might break existing applications which 23823aac3ebeSThomas Gleixner allocate a too small sigaltstack but 'work' because they 23833aac3ebeSThomas Gleixner never get a signal delivered. 23843aac3ebeSThomas Gleixner 23853aac3ebeSThomas Gleixner Say 'N' unless you want to really enforce this check. 23863aac3ebeSThomas Gleixner 2387b700e7f0SSeth Jenningssource "kernel/livepatch/Kconfig" 2388b700e7f0SSeth Jennings 2389506f1d07SSam Ravnborgendmenu 2390506f1d07SSam Ravnborg 23911ca3683cSUros Bizjakconfig CC_HAS_NAMED_AS 23921ca3683cSUros Bizjak def_bool CC_IS_GCC && GCC_VERSION >= 120100 23931ca3683cSUros Bizjak 23941ca3683cSUros Bizjakconfig USE_X86_SEG_SUPPORT 23951ca3683cSUros Bizjak def_bool y 2396*e29aad08SUros Bizjak depends on CC_HAS_NAMED_AS 2397*e29aad08SUros Bizjak # 2398*e29aad08SUros Bizjak # -fsanitize=kernel-address (KASAN) is at the moment incompatible 2399*e29aad08SUros Bizjak # with named address spaces - see GCC PR sanitizer/111736. 2400*e29aad08SUros Bizjak # 2401*e29aad08SUros Bizjak depends on !KASAN 24021ca3683cSUros Bizjak 2403f43b9876SPeter Zijlstraconfig CC_HAS_SLS 2404f43b9876SPeter Zijlstra def_bool $(cc-option,-mharden-sls=all) 2405f43b9876SPeter Zijlstra 2406f43b9876SPeter Zijlstraconfig CC_HAS_RETURN_THUNK 2407f43b9876SPeter Zijlstra def_bool $(cc-option,-mfunction-return=thunk-extern) 2408f43b9876SPeter Zijlstra 2409bea75b33SThomas Gleixnerconfig CC_HAS_ENTRY_PADDING 2410bea75b33SThomas Gleixner def_bool $(cc-option,-fpatchable-function-entry=16,16) 2411bea75b33SThomas Gleixner 2412bea75b33SThomas Gleixnerconfig FUNCTION_PADDING_CFI 2413bea75b33SThomas Gleixner int 2414bea75b33SThomas Gleixner default 59 if FUNCTION_ALIGNMENT_64B 2415bea75b33SThomas Gleixner default 27 if FUNCTION_ALIGNMENT_32B 2416bea75b33SThomas Gleixner default 11 if FUNCTION_ALIGNMENT_16B 2417bea75b33SThomas Gleixner default 3 if FUNCTION_ALIGNMENT_8B 2418bea75b33SThomas Gleixner default 0 2419bea75b33SThomas Gleixner 2420bea75b33SThomas Gleixner# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG 2421bea75b33SThomas Gleixner# except Kconfig can't do arithmetic :/ 2422bea75b33SThomas Gleixnerconfig FUNCTION_PADDING_BYTES 2423bea75b33SThomas Gleixner int 2424bea75b33SThomas Gleixner default FUNCTION_PADDING_CFI if CFI_CLANG 2425bea75b33SThomas Gleixner default FUNCTION_ALIGNMENT 2426bea75b33SThomas Gleixner 2427931ab636SPeter Zijlstraconfig CALL_PADDING 2428931ab636SPeter Zijlstra def_bool n 2429931ab636SPeter Zijlstra depends on CC_HAS_ENTRY_PADDING && OBJTOOL 2430931ab636SPeter Zijlstra select FUNCTION_ALIGNMENT_16B 2431931ab636SPeter Zijlstra 2432931ab636SPeter Zijlstraconfig FINEIBT 2433931ab636SPeter Zijlstra def_bool y 2434931ab636SPeter Zijlstra depends on X86_KERNEL_IBT && CFI_CLANG && RETPOLINE 2435931ab636SPeter Zijlstra select CALL_PADDING 2436931ab636SPeter Zijlstra 24378f7c0d8bSThomas Gleixnerconfig HAVE_CALL_THUNKS 24388f7c0d8bSThomas Gleixner def_bool y 2439bea75b33SThomas Gleixner depends on CC_HAS_ENTRY_PADDING && RETHUNK && OBJTOOL 24408f7c0d8bSThomas Gleixner 24418f7c0d8bSThomas Gleixnerconfig CALL_THUNKS 24428f7c0d8bSThomas Gleixner def_bool n 2443931ab636SPeter Zijlstra select CALL_PADDING 24448f7c0d8bSThomas Gleixner 2445b341b20dSPeter Zijlstraconfig PREFIX_SYMBOLS 2446b341b20dSPeter Zijlstra def_bool y 2447931ab636SPeter Zijlstra depends on CALL_PADDING && !CFI_CLANG 2448b341b20dSPeter Zijlstra 2449f43b9876SPeter Zijlstramenuconfig SPECULATION_MITIGATIONS 2450f43b9876SPeter Zijlstra bool "Mitigations for speculative execution vulnerabilities" 2451f43b9876SPeter Zijlstra default y 2452f43b9876SPeter Zijlstra help 2453f43b9876SPeter Zijlstra Say Y here to enable options which enable mitigations for 2454f43b9876SPeter Zijlstra speculative execution hardware vulnerabilities. 2455f43b9876SPeter Zijlstra 2456f43b9876SPeter Zijlstra If you say N, all mitigations will be disabled. You really 2457f43b9876SPeter Zijlstra should know what you are doing to say so. 2458f43b9876SPeter Zijlstra 2459f43b9876SPeter Zijlstraif SPECULATION_MITIGATIONS 2460f43b9876SPeter Zijlstra 2461f43b9876SPeter Zijlstraconfig PAGE_TABLE_ISOLATION 2462f43b9876SPeter Zijlstra bool "Remove the kernel mapping in user mode" 2463f43b9876SPeter Zijlstra default y 2464f43b9876SPeter Zijlstra depends on (X86_64 || X86_PAE) 2465f43b9876SPeter Zijlstra help 2466f43b9876SPeter Zijlstra This feature reduces the number of hardware side channels by 2467f43b9876SPeter Zijlstra ensuring that the majority of kernel addresses are not mapped 2468f43b9876SPeter Zijlstra into userspace. 2469f43b9876SPeter Zijlstra 2470ff61f079SJonathan Corbet See Documentation/arch/x86/pti.rst for more details. 2471f43b9876SPeter Zijlstra 2472f43b9876SPeter Zijlstraconfig RETPOLINE 2473f43b9876SPeter Zijlstra bool "Avoid speculative indirect branches in kernel" 2474f43b9876SPeter Zijlstra select OBJTOOL if HAVE_OBJTOOL 2475f43b9876SPeter Zijlstra default y 2476f43b9876SPeter Zijlstra help 2477f43b9876SPeter Zijlstra Compile kernel with the retpoline compiler options to guard against 2478f43b9876SPeter Zijlstra kernel-to-user data leaks by avoiding speculative indirect 2479f43b9876SPeter Zijlstra branches. Requires a compiler with -mindirect-branch=thunk-extern 2480f43b9876SPeter Zijlstra support for full protection. The kernel may run slower. 2481f43b9876SPeter Zijlstra 2482f43b9876SPeter Zijlstraconfig RETHUNK 2483f43b9876SPeter Zijlstra bool "Enable return-thunks" 2484f43b9876SPeter Zijlstra depends on RETPOLINE && CC_HAS_RETURN_THUNK 2485f43b9876SPeter Zijlstra select OBJTOOL if HAVE_OBJTOOL 2486b648ab48SBen Hutchings default y if X86_64 2487f43b9876SPeter Zijlstra help 2488f43b9876SPeter Zijlstra Compile the kernel with the return-thunks compiler option to guard 2489f43b9876SPeter Zijlstra against kernel-to-user data leaks by avoiding return speculation. 2490f43b9876SPeter Zijlstra Requires a compiler with -mfunction-return=thunk-extern 2491f43b9876SPeter Zijlstra support for full protection. The kernel may run slower. 2492f43b9876SPeter Zijlstra 2493f43b9876SPeter Zijlstraconfig CPU_UNRET_ENTRY 2494f43b9876SPeter Zijlstra bool "Enable UNRET on kernel entry" 2495b648ab48SBen Hutchings depends on CPU_SUP_AMD && RETHUNK && X86_64 2496f43b9876SPeter Zijlstra default y 2497f43b9876SPeter Zijlstra help 2498f43b9876SPeter Zijlstra Compile the kernel with support for the retbleed=unret mitigation. 2499f43b9876SPeter Zijlstra 250080e4c1cdSThomas Gleixnerconfig CALL_DEPTH_TRACKING 250180e4c1cdSThomas Gleixner bool "Mitigate RSB underflow with call depth tracking" 250280e4c1cdSThomas Gleixner depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS 250380e4c1cdSThomas Gleixner select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 250480e4c1cdSThomas Gleixner select CALL_THUNKS 250580e4c1cdSThomas Gleixner default y 250680e4c1cdSThomas Gleixner help 250780e4c1cdSThomas Gleixner Compile the kernel with call depth tracking to mitigate the Intel 250880e4c1cdSThomas Gleixner SKL Return-Speculation-Buffer (RSB) underflow issue. The 250980e4c1cdSThomas Gleixner mitigation is off by default and needs to be enabled on the 251080e4c1cdSThomas Gleixner kernel command line via the retbleed=stuff option. For 251180e4c1cdSThomas Gleixner non-affected systems the overhead of this option is marginal as 251280e4c1cdSThomas Gleixner the call depth tracking is using run-time generated call thunks 251380e4c1cdSThomas Gleixner in a compiler generated padding area and call patching. This 251480e4c1cdSThomas Gleixner increases text size by ~5%. For non affected systems this space 251580e4c1cdSThomas Gleixner is unused. On affected SKL systems this results in a significant 251680e4c1cdSThomas Gleixner performance gain over the IBRS mitigation. 251780e4c1cdSThomas Gleixner 2518e81dc127SThomas Gleixnerconfig CALL_THUNKS_DEBUG 2519e81dc127SThomas Gleixner bool "Enable call thunks and call depth tracking debugging" 2520e81dc127SThomas Gleixner depends on CALL_DEPTH_TRACKING 2521e81dc127SThomas Gleixner select FUNCTION_ALIGNMENT_32B 2522e81dc127SThomas Gleixner default n 2523e81dc127SThomas Gleixner help 2524e81dc127SThomas Gleixner Enable call/ret counters for imbalance detection and build in 2525e81dc127SThomas Gleixner a noisy dmesg about callthunks generation and call patching for 2526e81dc127SThomas Gleixner trouble shooting. The debug prints need to be enabled on the 2527e81dc127SThomas Gleixner kernel command line with 'debug-callthunks'. 252854628de6SRandy Dunlap Only enable this when you are debugging call thunks as this 252954628de6SRandy Dunlap creates a noticeable runtime overhead. If unsure say N. 253080e4c1cdSThomas Gleixner 2531f43b9876SPeter Zijlstraconfig CPU_IBPB_ENTRY 2532f43b9876SPeter Zijlstra bool "Enable IBPB on kernel entry" 2533b648ab48SBen Hutchings depends on CPU_SUP_AMD && X86_64 2534f43b9876SPeter Zijlstra default y 2535f43b9876SPeter Zijlstra help 2536f43b9876SPeter Zijlstra Compile the kernel with support for the retbleed=ibpb mitigation. 2537f43b9876SPeter Zijlstra 2538f43b9876SPeter Zijlstraconfig CPU_IBRS_ENTRY 2539f43b9876SPeter Zijlstra bool "Enable IBRS on kernel entry" 2540b648ab48SBen Hutchings depends on CPU_SUP_INTEL && X86_64 2541f43b9876SPeter Zijlstra default y 2542f43b9876SPeter Zijlstra help 2543f43b9876SPeter Zijlstra Compile the kernel with support for the spectre_v2=ibrs mitigation. 2544f43b9876SPeter Zijlstra This mitigates both spectre_v2 and retbleed at great cost to 2545f43b9876SPeter Zijlstra performance. 2546f43b9876SPeter Zijlstra 2547fb3bd914SBorislav Petkov (AMD)config CPU_SRSO 2548fb3bd914SBorislav Petkov (AMD) bool "Mitigate speculative RAS overflow on AMD" 2549fb3bd914SBorislav Petkov (AMD) depends on CPU_SUP_AMD && X86_64 && RETHUNK 2550fb3bd914SBorislav Petkov (AMD) default y 2551fb3bd914SBorislav Petkov (AMD) help 2552fb3bd914SBorislav Petkov (AMD) Enable the SRSO mitigation needed on AMD Zen1-4 machines. 2553fb3bd914SBorislav Petkov (AMD) 2554f43b9876SPeter Zijlstraconfig SLS 2555f43b9876SPeter Zijlstra bool "Mitigate Straight-Line-Speculation" 2556f43b9876SPeter Zijlstra depends on CC_HAS_SLS && X86_64 2557f43b9876SPeter Zijlstra select OBJTOOL if HAVE_OBJTOOL 2558f43b9876SPeter Zijlstra default n 2559f43b9876SPeter Zijlstra help 2560f43b9876SPeter Zijlstra Compile the kernel with straight-line-speculation options to guard 2561f43b9876SPeter Zijlstra against straight line speculation. The kernel image might be slightly 2562f43b9876SPeter Zijlstra larger. 2563f43b9876SPeter Zijlstra 256453cf5797SDaniel Sneddonconfig GDS_FORCE_MITIGATION 256553cf5797SDaniel Sneddon bool "Force GDS Mitigation" 256653cf5797SDaniel Sneddon depends on CPU_SUP_INTEL 256753cf5797SDaniel Sneddon default n 256853cf5797SDaniel Sneddon help 256953cf5797SDaniel Sneddon Gather Data Sampling (GDS) is a hardware vulnerability which allows 257053cf5797SDaniel Sneddon unprivileged speculative access to data which was previously stored in 257153cf5797SDaniel Sneddon vector registers. 257253cf5797SDaniel Sneddon 257353cf5797SDaniel Sneddon This option is equivalent to setting gather_data_sampling=force on the 257453cf5797SDaniel Sneddon command line. The microcode mitigation is used if present, otherwise 257553cf5797SDaniel Sneddon AVX is disabled as a mitigation. On affected systems that are missing 257653cf5797SDaniel Sneddon the microcode any userspace code that unconditionally uses AVX will 257753cf5797SDaniel Sneddon break with this option set. 257853cf5797SDaniel Sneddon 257953cf5797SDaniel Sneddon Setting this option on systems not vulnerable to GDS has no effect. 258053cf5797SDaniel Sneddon 258153cf5797SDaniel Sneddon If in doubt, say N. 258253cf5797SDaniel Sneddon 2583f43b9876SPeter Zijlstraendif 2584f43b9876SPeter Zijlstra 25853072e413SMichal Hockoconfig ARCH_HAS_ADD_PAGES 25863072e413SMichal Hocko def_bool y 25875c11f00bSDavid Hildenbrand depends on ARCH_ENABLE_MEMORY_HOTPLUG 25883072e413SMichal Hocko 2589da85f865SBjorn Helgaasmenu "Power management and ACPI options" 2590e279b6c1SSam Ravnborg 2591e279b6c1SSam Ravnborgconfig ARCH_HIBERNATION_HEADER 25923c2362e6SHarvey Harrison def_bool y 259344556530SZhimin Gu depends on HIBERNATION 2594e279b6c1SSam Ravnborg 2595e279b6c1SSam Ravnborgsource "kernel/power/Kconfig" 2596e279b6c1SSam Ravnborg 2597e279b6c1SSam Ravnborgsource "drivers/acpi/Kconfig" 2598e279b6c1SSam Ravnborg 2599a6b68076SAndi Kleenconfig X86_APM_BOOT 26006fc108a0SJan Beulich def_bool y 2601282e5aabSPaul Bolle depends on APM 2602a6b68076SAndi Kleen 2603e279b6c1SSam Ravnborgmenuconfig APM 2604e279b6c1SSam Ravnborg tristate "APM (Advanced Power Management) BIOS support" 2605efefa6f6SIngo Molnar depends on X86_32 && PM_SLEEP 2606a7f7f624SMasahiro Yamada help 2607e279b6c1SSam Ravnborg APM is a BIOS specification for saving power using several different 2608e279b6c1SSam Ravnborg techniques. This is mostly useful for battery powered laptops with 2609e279b6c1SSam Ravnborg APM compliant BIOSes. If you say Y here, the system time will be 2610e279b6c1SSam Ravnborg reset after a RESUME operation, the /proc/apm device will provide 2611e279b6c1SSam Ravnborg battery status information, and user-space programs will receive 2612e279b6c1SSam Ravnborg notification of APM "events" (e.g. battery status change). 2613e279b6c1SSam Ravnborg 2614e279b6c1SSam Ravnborg If you select "Y" here, you can disable actual use of the APM 2615e279b6c1SSam Ravnborg BIOS by passing the "apm=off" option to the kernel at boot time. 2616e279b6c1SSam Ravnborg 2617e279b6c1SSam Ravnborg Note that the APM support is almost completely disabled for 2618e279b6c1SSam Ravnborg machines with more than one CPU. 2619e279b6c1SSam Ravnborg 2620e279b6c1SSam Ravnborg In order to use APM, you will need supporting software. For location 2621151f4e2bSMauro Carvalho Chehab and more information, read <file:Documentation/power/apm-acpi.rst> 26222dc98fd3SMichael Witten and the Battery Powered Linux mini-HOWTO, available from 2623e279b6c1SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 2624e279b6c1SSam Ravnborg 2625e279b6c1SSam Ravnborg This driver does not spin down disk drives (see the hdparm(8) 2626e279b6c1SSam Ravnborg manpage ("man 8 hdparm") for that), and it doesn't turn off 2627e279b6c1SSam Ravnborg VESA-compliant "green" monitors. 2628e279b6c1SSam Ravnborg 2629e279b6c1SSam Ravnborg This driver does not support the TI 4000M TravelMate and the ACER 2630e279b6c1SSam Ravnborg 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2631e279b6c1SSam Ravnborg desktop machines also don't have compliant BIOSes, and this driver 2632e279b6c1SSam Ravnborg may cause those machines to panic during the boot phase. 2633e279b6c1SSam Ravnborg 2634e279b6c1SSam Ravnborg Generally, if you don't have a battery in your machine, there isn't 2635e279b6c1SSam Ravnborg much point in using this driver and you should say N. If you get 2636e279b6c1SSam Ravnborg random kernel OOPSes or reboots that don't seem to be related to 2637e279b6c1SSam Ravnborg anything, try disabling/enabling this option (or disabling/enabling 2638e279b6c1SSam Ravnborg APM in your BIOS). 2639e279b6c1SSam Ravnborg 2640e279b6c1SSam Ravnborg Some other things you should try when experiencing seemingly random, 2641e279b6c1SSam Ravnborg "weird" problems: 2642e279b6c1SSam Ravnborg 2643e279b6c1SSam Ravnborg 1) make sure that you have enough swap space and that it is 2644e279b6c1SSam Ravnborg enabled. 26457987448fSStephen Kitt 2) pass the "idle=poll" option to the kernel 2646e279b6c1SSam Ravnborg 3) switch on floating point emulation in the kernel and pass 2647e279b6c1SSam Ravnborg the "no387" option to the kernel 2648e279b6c1SSam Ravnborg 4) pass the "floppy=nodma" option to the kernel 2649e279b6c1SSam Ravnborg 5) pass the "mem=4M" option to the kernel (thereby disabling 2650e279b6c1SSam Ravnborg all but the first 4 MB of RAM) 2651e279b6c1SSam Ravnborg 6) make sure that the CPU is not over clocked. 2652e279b6c1SSam Ravnborg 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2653e279b6c1SSam Ravnborg 8) disable the cache from your BIOS settings 2654e279b6c1SSam Ravnborg 9) install a fan for the video card or exchange video RAM 2655e279b6c1SSam Ravnborg 10) install a better fan for the CPU 2656e279b6c1SSam Ravnborg 11) exchange RAM chips 2657e279b6c1SSam Ravnborg 12) exchange the motherboard. 2658e279b6c1SSam Ravnborg 2659e279b6c1SSam Ravnborg To compile this driver as a module, choose M here: the 2660e279b6c1SSam Ravnborg module will be called apm. 2661e279b6c1SSam Ravnborg 2662e279b6c1SSam Ravnborgif APM 2663e279b6c1SSam Ravnborg 2664e279b6c1SSam Ravnborgconfig APM_IGNORE_USER_SUSPEND 2665e279b6c1SSam Ravnborg bool "Ignore USER SUSPEND" 2666a7f7f624SMasahiro Yamada help 2667e279b6c1SSam Ravnborg This option will ignore USER SUSPEND requests. On machines with a 2668e279b6c1SSam Ravnborg compliant APM BIOS, you want to say N. However, on the NEC Versa M 2669e279b6c1SSam Ravnborg series notebooks, it is necessary to say Y because of a BIOS bug. 2670e279b6c1SSam Ravnborg 2671e279b6c1SSam Ravnborgconfig APM_DO_ENABLE 2672e279b6c1SSam Ravnborg bool "Enable PM at boot time" 2673a7f7f624SMasahiro Yamada help 2674e279b6c1SSam Ravnborg Enable APM features at boot time. From page 36 of the APM BIOS 2675e279b6c1SSam Ravnborg specification: "When disabled, the APM BIOS does not automatically 2676e279b6c1SSam Ravnborg power manage devices, enter the Standby State, enter the Suspend 2677e279b6c1SSam Ravnborg State, or take power saving steps in response to CPU Idle calls." 2678e279b6c1SSam Ravnborg This driver will make CPU Idle calls when Linux is idle (unless this 2679e279b6c1SSam Ravnborg feature is turned off -- see "Do CPU IDLE calls", below). This 2680e279b6c1SSam Ravnborg should always save battery power, but more complicated APM features 2681e279b6c1SSam Ravnborg will be dependent on your BIOS implementation. You may need to turn 2682e279b6c1SSam Ravnborg this option off if your computer hangs at boot time when using APM 2683e279b6c1SSam Ravnborg support, or if it beeps continuously instead of suspending. Turn 2684e279b6c1SSam Ravnborg this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2685e279b6c1SSam Ravnborg T400CDT. This is off by default since most machines do fine without 2686e279b6c1SSam Ravnborg this feature. 2687e279b6c1SSam Ravnborg 2688e279b6c1SSam Ravnborgconfig APM_CPU_IDLE 2689dd8af076SLen Brown depends on CPU_IDLE 2690e279b6c1SSam Ravnborg bool "Make CPU Idle calls when idle" 2691a7f7f624SMasahiro Yamada help 2692e279b6c1SSam Ravnborg Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2693e279b6c1SSam Ravnborg On some machines, this can activate improved power savings, such as 2694e279b6c1SSam Ravnborg a slowed CPU clock rate, when the machine is idle. These idle calls 2695e279b6c1SSam Ravnborg are made after the idle loop has run for some length of time (e.g., 2696e279b6c1SSam Ravnborg 333 mS). On some machines, this will cause a hang at boot time or 2697e279b6c1SSam Ravnborg whenever the CPU becomes idle. (On machines with more than one CPU, 2698e279b6c1SSam Ravnborg this option does nothing.) 2699e279b6c1SSam Ravnborg 2700e279b6c1SSam Ravnborgconfig APM_DISPLAY_BLANK 2701e279b6c1SSam Ravnborg bool "Enable console blanking using APM" 2702a7f7f624SMasahiro Yamada help 2703e279b6c1SSam Ravnborg Enable console blanking using the APM. Some laptops can use this to 2704e279b6c1SSam Ravnborg turn off the LCD backlight when the screen blanker of the Linux 2705e279b6c1SSam Ravnborg virtual console blanks the screen. Note that this is only used by 2706e279b6c1SSam Ravnborg the virtual console screen blanker, and won't turn off the backlight 2707e279b6c1SSam Ravnborg when using the X Window system. This also doesn't have anything to 2708e279b6c1SSam Ravnborg do with your VESA-compliant power-saving monitor. Further, this 2709e279b6c1SSam Ravnborg option doesn't work for all laptops -- it might not turn off your 2710e279b6c1SSam Ravnborg backlight at all, or it might print a lot of errors to the console, 2711e279b6c1SSam Ravnborg especially if you are using gpm. 2712e279b6c1SSam Ravnborg 2713e279b6c1SSam Ravnborgconfig APM_ALLOW_INTS 2714e279b6c1SSam Ravnborg bool "Allow interrupts during APM BIOS calls" 2715a7f7f624SMasahiro Yamada help 2716e279b6c1SSam Ravnborg Normally we disable external interrupts while we are making calls to 2717e279b6c1SSam Ravnborg the APM BIOS as a measure to lessen the effects of a badly behaving 2718e279b6c1SSam Ravnborg BIOS implementation. The BIOS should reenable interrupts if it 2719e279b6c1SSam Ravnborg needs to. Unfortunately, some BIOSes do not -- especially those in 2720e279b6c1SSam Ravnborg many of the newer IBM Thinkpads. If you experience hangs when you 2721e279b6c1SSam Ravnborg suspend, try setting this to Y. Otherwise, say N. 2722e279b6c1SSam Ravnborg 2723e279b6c1SSam Ravnborgendif # APM 2724e279b6c1SSam Ravnborg 2725bb0a56ecSDave Jonessource "drivers/cpufreq/Kconfig" 2726e279b6c1SSam Ravnborg 2727e279b6c1SSam Ravnborgsource "drivers/cpuidle/Kconfig" 2728e279b6c1SSam Ravnborg 272927471fdbSAndy Henroidsource "drivers/idle/Kconfig" 273027471fdbSAndy Henroid 2731e279b6c1SSam Ravnborgendmenu 2732e279b6c1SSam Ravnborg 2733e279b6c1SSam Ravnborgmenu "Bus options (PCI etc.)" 2734e279b6c1SSam Ravnborg 2735e279b6c1SSam Ravnborgchoice 2736e279b6c1SSam Ravnborg prompt "PCI access mode" 2737efefa6f6SIngo Molnar depends on X86_32 && PCI 2738e279b6c1SSam Ravnborg default PCI_GOANY 2739a7f7f624SMasahiro Yamada help 2740e279b6c1SSam Ravnborg On PCI systems, the BIOS can be used to detect the PCI devices and 2741e279b6c1SSam Ravnborg determine their configuration. However, some old PCI motherboards 2742e279b6c1SSam Ravnborg have BIOS bugs and may crash if this is done. Also, some embedded 2743e279b6c1SSam Ravnborg PCI-based systems don't have any BIOS at all. Linux can also try to 2744e279b6c1SSam Ravnborg detect the PCI hardware directly without using the BIOS. 2745e279b6c1SSam Ravnborg 2746e279b6c1SSam Ravnborg With this option, you can specify how Linux should detect the 2747e279b6c1SSam Ravnborg PCI devices. If you choose "BIOS", the BIOS will be used, 2748e279b6c1SSam Ravnborg if you choose "Direct", the BIOS won't be used, and if you 2749e279b6c1SSam Ravnborg choose "MMConfig", then PCI Express MMCONFIG will be used. 2750e279b6c1SSam Ravnborg If you choose "Any", the kernel will try MMCONFIG, then the 2751e279b6c1SSam Ravnborg direct access method and falls back to the BIOS if that doesn't 2752e279b6c1SSam Ravnborg work. If unsure, go with the default, which is "Any". 2753e279b6c1SSam Ravnborg 2754e279b6c1SSam Ravnborgconfig PCI_GOBIOS 2755e279b6c1SSam Ravnborg bool "BIOS" 2756e279b6c1SSam Ravnborg 2757e279b6c1SSam Ravnborgconfig PCI_GOMMCONFIG 2758e279b6c1SSam Ravnborg bool "MMConfig" 2759e279b6c1SSam Ravnborg 2760e279b6c1SSam Ravnborgconfig PCI_GODIRECT 2761e279b6c1SSam Ravnborg bool "Direct" 2762e279b6c1SSam Ravnborg 27633ef0e1f8SAndres Salomonconfig PCI_GOOLPC 276476fb6570SDaniel Drake bool "OLPC XO-1" 27653ef0e1f8SAndres Salomon depends on OLPC 27663ef0e1f8SAndres Salomon 27672bdd1b03SAndres Salomonconfig PCI_GOANY 27682bdd1b03SAndres Salomon bool "Any" 27692bdd1b03SAndres Salomon 2770e279b6c1SSam Ravnborgendchoice 2771e279b6c1SSam Ravnborg 2772e279b6c1SSam Ravnborgconfig PCI_BIOS 27733c2362e6SHarvey Harrison def_bool y 2774efefa6f6SIngo Molnar depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2775e279b6c1SSam Ravnborg 2776e279b6c1SSam Ravnborg# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2777e279b6c1SSam Ravnborgconfig PCI_DIRECT 27783c2362e6SHarvey Harrison def_bool y 27790aba496fSShaohua Li depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2780e279b6c1SSam Ravnborg 2781e279b6c1SSam Ravnborgconfig PCI_MMCONFIG 2782b45c9f36SJan Kiszka bool "Support mmconfig PCI config space access" if X86_64 2783b45c9f36SJan Kiszka default y 27844590d98fSAndy Shevchenko depends on PCI && (ACPI || JAILHOUSE_GUEST) 2785b45c9f36SJan Kiszka depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2786e279b6c1SSam Ravnborg 27873ef0e1f8SAndres Salomonconfig PCI_OLPC 27882bdd1b03SAndres Salomon def_bool y 27892bdd1b03SAndres Salomon depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 27903ef0e1f8SAndres Salomon 2791b5401a96SAlex Nixonconfig PCI_XEN 2792b5401a96SAlex Nixon def_bool y 2793b5401a96SAlex Nixon depends on PCI && XEN 2794b5401a96SAlex Nixon 27958364e1f8SJan Kiszkaconfig MMCONF_FAM10H 27968364e1f8SJan Kiszka def_bool y 27978364e1f8SJan Kiszka depends on X86_64 && PCI_MMCONFIG && ACPI 2798e279b6c1SSam Ravnborg 27993f6ea84aSIra W. Snyderconfig PCI_CNB20LE_QUIRK 28006a108a14SDavid Rientjes bool "Read CNB20LE Host Bridge Windows" if EXPERT 28016ea30386SKees Cook depends on PCI 28023f6ea84aSIra W. Snyder help 28033f6ea84aSIra W. Snyder Read the PCI windows out of the CNB20LE host bridge. This allows 28043f6ea84aSIra W. Snyder PCI hotplug to work on systems with the CNB20LE chipset which do 28053f6ea84aSIra W. Snyder not have ACPI. 28063f6ea84aSIra W. Snyder 280764a5fed6SBjorn Helgaas There's no public spec for this chipset, and this functionality 280864a5fed6SBjorn Helgaas is known to be incomplete. 280964a5fed6SBjorn Helgaas 281064a5fed6SBjorn Helgaas You should say N unless you know you need this. 281164a5fed6SBjorn Helgaas 28123a495511SWilliam Breathitt Grayconfig ISA_BUS 281317a2a129SWilliam Breathitt Gray bool "ISA bus support on modern systems" if EXPERT 28143a495511SWilliam Breathitt Gray help 281517a2a129SWilliam Breathitt Gray Expose ISA bus device drivers and options available for selection and 281617a2a129SWilliam Breathitt Gray configuration. Enable this option if your target machine has an ISA 281717a2a129SWilliam Breathitt Gray bus. ISA is an older system, displaced by PCI and newer bus 281817a2a129SWilliam Breathitt Gray architectures -- if your target machine is modern, it probably does 281917a2a129SWilliam Breathitt Gray not have an ISA bus. 28203a495511SWilliam Breathitt Gray 28213a495511SWilliam Breathitt Gray If unsure, say N. 28223a495511SWilliam Breathitt Gray 28231c00f016SDavid Rientjes# x86_64 have no ISA slots, but can have ISA-style DMA. 2824e279b6c1SSam Ravnborgconfig ISA_DMA_API 28251c00f016SDavid Rientjes bool "ISA-style DMA support" if (X86_64 && EXPERT) 28261c00f016SDavid Rientjes default y 28271c00f016SDavid Rientjes help 28281c00f016SDavid Rientjes Enables ISA-style DMA support for devices requiring such controllers. 28291c00f016SDavid Rientjes If unsure, say Y. 2830e279b6c1SSam Ravnborg 283151e68d05SLinus Torvaldsif X86_32 283251e68d05SLinus Torvalds 2833e279b6c1SSam Ravnborgconfig ISA 2834e279b6c1SSam Ravnborg bool "ISA support" 2835a7f7f624SMasahiro Yamada help 2836e279b6c1SSam Ravnborg Find out whether you have ISA slots on your motherboard. ISA is the 2837e279b6c1SSam Ravnborg name of a bus system, i.e. the way the CPU talks to the other stuff 2838e279b6c1SSam Ravnborg inside your box. Other bus systems are PCI, EISA, MicroChannel 2839e279b6c1SSam Ravnborg (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2840e279b6c1SSam Ravnborg newer boards don't support it. If you have ISA, say Y, otherwise N. 2841e279b6c1SSam Ravnborg 2842e279b6c1SSam Ravnborgconfig SCx200 2843e279b6c1SSam Ravnborg tristate "NatSemi SCx200 support" 2844a7f7f624SMasahiro Yamada help 2845e279b6c1SSam Ravnborg This provides basic support for National Semiconductor's 2846e279b6c1SSam Ravnborg (now AMD's) Geode processors. The driver probes for the 2847e279b6c1SSam Ravnborg PCI-IDs of several on-chip devices, so its a good dependency 2848e279b6c1SSam Ravnborg for other scx200_* drivers. 2849e279b6c1SSam Ravnborg 2850e279b6c1SSam Ravnborg If compiled as a module, the driver is named scx200. 2851e279b6c1SSam Ravnborg 2852e279b6c1SSam Ravnborgconfig SCx200HR_TIMER 2853e279b6c1SSam Ravnborg tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2854592913ecSJohn Stultz depends on SCx200 2855e279b6c1SSam Ravnborg default y 2856a7f7f624SMasahiro Yamada help 2857e279b6c1SSam Ravnborg This driver provides a clocksource built upon the on-chip 2858e279b6c1SSam Ravnborg 27MHz high-resolution timer. Its also a workaround for 2859e279b6c1SSam Ravnborg NSC Geode SC-1100's buggy TSC, which loses time when the 2860e279b6c1SSam Ravnborg processor goes idle (as is done by the scheduler). The 2861e279b6c1SSam Ravnborg other workaround is idle=poll boot option. 2862e279b6c1SSam Ravnborg 28633ef0e1f8SAndres Salomonconfig OLPC 28643ef0e1f8SAndres Salomon bool "One Laptop Per Child support" 286554008979SThomas Gleixner depends on !X86_PAE 28663c554946SAndres Salomon select GPIOLIB 2867dc3119e7SThomas Gleixner select OF 286845bb1674SDaniel Drake select OF_PROMTREE 2869b4e51854SGrant Likely select IRQ_DOMAIN 28700c3d931bSLubomir Rintel select OLPC_EC 2871a7f7f624SMasahiro Yamada help 28723ef0e1f8SAndres Salomon Add support for detecting the unique features of the OLPC 28733ef0e1f8SAndres Salomon XO hardware. 28743ef0e1f8SAndres Salomon 2875a3128588SDaniel Drakeconfig OLPC_XO1_PM 2876a3128588SDaniel Drake bool "OLPC XO-1 Power Management" 2877fa112cf1SBorislav Petkov depends on OLPC && MFD_CS5535=y && PM_SLEEP 2878a7f7f624SMasahiro Yamada help 287997c4cb71SDaniel Drake Add support for poweroff and suspend of the OLPC XO-1 laptop. 2880bf1ebf00SDaniel Drake 2881cfee9597SDaniel Drakeconfig OLPC_XO1_RTC 2882cfee9597SDaniel Drake bool "OLPC XO-1 Real Time Clock" 2883cfee9597SDaniel Drake depends on OLPC_XO1_PM && RTC_DRV_CMOS 2884a7f7f624SMasahiro Yamada help 2885cfee9597SDaniel Drake Add support for the XO-1 real time clock, which can be used as a 2886cfee9597SDaniel Drake programmable wakeup source. 2887cfee9597SDaniel Drake 28887feda8e9SDaniel Drakeconfig OLPC_XO1_SCI 28897feda8e9SDaniel Drake bool "OLPC XO-1 SCI extras" 289092e830f2SArnd Bergmann depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2891ed8e47feSRandy Dunlap depends on INPUT=y 2892d8d01a63SDaniel Drake select POWER_SUPPLY 2893a7f7f624SMasahiro Yamada help 28947feda8e9SDaniel Drake Add support for SCI-based features of the OLPC XO-1 laptop: 28957bc74b3dSDaniel Drake - EC-driven system wakeups 28967feda8e9SDaniel Drake - Power button 28977bc74b3dSDaniel Drake - Ebook switch 28982cf2baeaSDaniel Drake - Lid switch 2899e1040ac6SDaniel Drake - AC adapter status updates 2900e1040ac6SDaniel Drake - Battery status updates 29017feda8e9SDaniel Drake 2902a0f30f59SDaniel Drakeconfig OLPC_XO15_SCI 2903a0f30f59SDaniel Drake bool "OLPC XO-1.5 SCI extras" 2904d8d01a63SDaniel Drake depends on OLPC && ACPI 2905d8d01a63SDaniel Drake select POWER_SUPPLY 2906a7f7f624SMasahiro Yamada help 2907a0f30f59SDaniel Drake Add support for SCI-based features of the OLPC XO-1.5 laptop: 2908a0f30f59SDaniel Drake - EC-driven system wakeups 2909a0f30f59SDaniel Drake - AC adapter status updates 2910a0f30f59SDaniel Drake - Battery status updates 2911e279b6c1SSam Ravnborg 2912d4f3e350SEd Wildgooseconfig ALIX 2913d4f3e350SEd Wildgoose bool "PCEngines ALIX System Support (LED setup)" 2914d4f3e350SEd Wildgoose select GPIOLIB 2915a7f7f624SMasahiro Yamada help 2916d4f3e350SEd Wildgoose This option enables system support for the PCEngines ALIX. 2917d4f3e350SEd Wildgoose At present this just sets up LEDs for GPIO control on 2918d4f3e350SEd Wildgoose ALIX2/3/6 boards. However, other system specific setup should 2919d4f3e350SEd Wildgoose get added here. 2920d4f3e350SEd Wildgoose 2921d4f3e350SEd Wildgoose Note: You must still enable the drivers for GPIO and LED support 2922d4f3e350SEd Wildgoose (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2923d4f3e350SEd Wildgoose 2924d4f3e350SEd Wildgoose Note: You have to set alix.force=1 for boards with Award BIOS. 2925d4f3e350SEd Wildgoose 2926da4e3302SPhilip Prindevilleconfig NET5501 2927da4e3302SPhilip Prindeville bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2928da4e3302SPhilip Prindeville select GPIOLIB 2929a7f7f624SMasahiro Yamada help 2930da4e3302SPhilip Prindeville This option enables system support for the Soekris Engineering net5501. 2931da4e3302SPhilip Prindeville 29323197059aSPhilip A. Prindevilleconfig GEOS 29333197059aSPhilip A. Prindeville bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 29343197059aSPhilip A. Prindeville select GPIOLIB 29353197059aSPhilip A. Prindeville depends on DMI 2936a7f7f624SMasahiro Yamada help 29373197059aSPhilip A. Prindeville This option enables system support for the Traverse Technologies GEOS. 29383197059aSPhilip A. Prindeville 29397d029125SVivien Didelotconfig TS5500 29407d029125SVivien Didelot bool "Technologic Systems TS-5500 platform support" 29417d029125SVivien Didelot depends on MELAN 29427d029125SVivien Didelot select CHECK_SIGNATURE 29437d029125SVivien Didelot select NEW_LEDS 29447d029125SVivien Didelot select LEDS_CLASS 2945a7f7f624SMasahiro Yamada help 29467d029125SVivien Didelot This option enables system support for the Technologic Systems TS-5500. 29477d029125SVivien Didelot 2948e279b6c1SSam Ravnborgendif # X86_32 2949e279b6c1SSam Ravnborg 295023ac4ae8SAndreas Herrmannconfig AMD_NB 2951e279b6c1SSam Ravnborg def_bool y 29520e152cd7SBorislav Petkov depends on CPU_SUP_AMD && PCI 2953e279b6c1SSam Ravnborg 2954e279b6c1SSam Ravnborgendmenu 2955e279b6c1SSam Ravnborg 29561572497cSChristoph Hellwigmenu "Binary Emulations" 2957e279b6c1SSam Ravnborg 2958e279b6c1SSam Ravnborgconfig IA32_EMULATION 2959e279b6c1SSam Ravnborg bool "IA32 Emulation" 2960e279b6c1SSam Ravnborg depends on X86_64 296139f88911SIngo Molnar select ARCH_WANT_OLD_COMPAT_IPC 2962d1603990SRandy Dunlap select BINFMT_ELF 296339f88911SIngo Molnar select COMPAT_OLD_SIGACTION 2964a7f7f624SMasahiro Yamada help 29655fd92e65SH. J. Lu Include code to run legacy 32-bit programs under a 29665fd92e65SH. J. Lu 64-bit kernel. You should likely turn this on, unless you're 29675fd92e65SH. J. Lu 100% sure that you don't have any 32-bit programs left. 2968e279b6c1SSam Ravnborg 296983a44a4fSMasahiro Yamadaconfig X86_X32_ABI 29706ea30386SKees Cook bool "x32 ABI for 64-bit mode" 29719b54050bSBrian Gerst depends on X86_64 2972aaeed6ecSNathan Chancellor # llvm-objcopy does not convert x86_64 .note.gnu.property or 2973aaeed6ecSNathan Chancellor # compressed debug sections to x86_x32 properly: 2974aaeed6ecSNathan Chancellor # https://github.com/ClangBuiltLinux/linux/issues/514 2975aaeed6ecSNathan Chancellor # https://github.com/ClangBuiltLinux/linux/issues/1141 2976aaeed6ecSNathan Chancellor depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm) 2977a7f7f624SMasahiro Yamada help 29785fd92e65SH. J. Lu Include code to run binaries for the x32 native 32-bit ABI 29795fd92e65SH. J. Lu for 64-bit processors. An x32 process gets access to the 29805fd92e65SH. J. Lu full 64-bit register file and wide data path while leaving 29815fd92e65SH. J. Lu pointers at 32 bits for smaller memory footprint. 29825fd92e65SH. J. Lu 2983953fee1dSIngo Molnarconfig COMPAT_32 2984953fee1dSIngo Molnar def_bool y 2985953fee1dSIngo Molnar depends on IA32_EMULATION || X86_32 2986953fee1dSIngo Molnar select HAVE_UID16 2987953fee1dSIngo Molnar select OLD_SIGSUSPEND3 2988953fee1dSIngo Molnar 2989e279b6c1SSam Ravnborgconfig COMPAT 29903c2362e6SHarvey Harrison def_bool y 299183a44a4fSMasahiro Yamada depends on IA32_EMULATION || X86_X32_ABI 2992e279b6c1SSam Ravnborg 2993e279b6c1SSam Ravnborgconfig COMPAT_FOR_U64_ALIGNMENT 29943120e25eSJan Beulich def_bool y 2995a9251280SLinus Torvalds depends on COMPAT 2996ee009e4aSDavid Howells 2997e279b6c1SSam Ravnborgendmenu 2998e279b6c1SSam Ravnborg 2999e5beae16SKeith Packardconfig HAVE_ATOMIC_IOMAP 3000e5beae16SKeith Packard def_bool y 3001e5beae16SKeith Packard depends on X86_32 3002e5beae16SKeith Packard 3003edf88417SAvi Kivitysource "arch/x86/kvm/Kconfig" 30045e8ebd84SJason A. Donenfeld 30055e8ebd84SJason A. Donenfeldsource "arch/x86/Kconfig.assembler" 3006