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 742792d84eSKees Cook select ARCH_HAS_CURRENT_STACK_POINTER 75fa5b6ec9SLaura Abbott select ARCH_HAS_DEBUG_VIRTUAL 76399145f9SAnshuman Khandual select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 7721266be9SDan Williams select ARCH_HAS_DEVMEM_IS_ALLOWED 78b1a57bbfSDouglas Anderson select ARCH_HAS_EARLY_DEBUG if KGDB 796471b825SIngo Molnar select ARCH_HAS_ELF_RANDOMIZE 8072d93104SLinus Torvalds select ARCH_HAS_FAST_MULTIPLIER 816974f0c4SDaniel Micay select ARCH_HAS_FORTIFY_SOURCE 82957e3facSRiku Voipio select ARCH_HAS_GCOV_PROFILE_ALL 83bece04b5SMarco Elver select ARCH_HAS_KCOV if X86_64 840c9c1d56SThiago Jung Bauermann select ARCH_HAS_MEM_ENCRYPT 8510bcc80eSMathieu Desnoyers select ARCH_HAS_MEMBARRIER_SYNC_CORE 8649f88c70SPaul E. McKenney select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS 870ebeea8cSDaniel Borkmann select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 88c763ea26SIngo Molnar select ARCH_HAS_PMEM_API if X86_64 8917596731SRobin Murphy select ARCH_HAS_PTE_DEVMAP if X86_64 903010a5eaSLaurent Dufour select ARCH_HAS_PTE_SPECIAL 91eed9a328SYu Zhao select ARCH_HAS_NONLEAF_PMD_YOUNG if PGTABLE_LEVELS > 2 920aed55afSDan Williams select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 93ec6347bbSDan Williams select ARCH_HAS_COPY_MC if X86_64 94d2852a22SDaniel Borkmann select ARCH_HAS_SET_MEMORY 95d253ca0cSRick Edgecombe select ARCH_HAS_SET_DIRECT_MAP 96ad21fc4fSLaura Abbott select ARCH_HAS_STRICT_KERNEL_RWX 97ad21fc4fSLaura Abbott select ARCH_HAS_STRICT_MODULE_RWX 98ac1ab12aSMathieu Desnoyers select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 9925c619e5SBrian Gerst select ARCH_HAS_SYSCALL_WRAPPER 100c6d30853SAndrey Ryabinin select ARCH_HAS_UBSAN_SANITIZE_ALL 1017e01ccb4SZong Li select ARCH_HAS_DEBUG_WX 10263703f37SKefeng Wang select ARCH_HAS_ZONE_DMA_SET if EXPERT 1036471b825SIngo Molnar select ARCH_HAVE_NMI_SAFE_CMPXCHG 1046471b825SIngo Molnar select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 10577fbbc81SMark Salter select ARCH_MIGHT_HAVE_PC_PARPORT 1065e2c18c0SMark Salter select ARCH_MIGHT_HAVE_PC_SERIO 1073599fe12SThomas Gleixner select ARCH_STACKWALK 1082c870e61SArnd Bergmann select ARCH_SUPPORTS_ACPI 1096471b825SIngo Molnar select ARCH_SUPPORTS_ATOMIC_RMW 1105d6ad668SMike Rapoport select ARCH_SUPPORTS_DEBUG_PAGEALLOC 111d283d422SPasha Tatashin select ARCH_SUPPORTS_PAGE_TABLE_CHECK if X86_64 1126471b825SIngo Molnar select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 11314df3267SThomas Gleixner select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 1143c516f89SSami Tolvanen select ARCH_SUPPORTS_CFI_CLANG if X86_64 1153c516f89SSami Tolvanen select ARCH_USES_CFI_TRAPS if X86_64 && CFI_CLANG 116583bfd48SNathan Chancellor select ARCH_SUPPORTS_LTO_CLANG 117583bfd48SNathan Chancellor select ARCH_SUPPORTS_LTO_CLANG_THIN 1186471b825SIngo Molnar select ARCH_USE_BUILTIN_BSWAP 119dce44566SAnshuman Khandual select ARCH_USE_MEMTEST 1206471b825SIngo Molnar select ARCH_USE_QUEUED_RWLOCKS 1216471b825SIngo Molnar select ARCH_USE_QUEUED_SPINLOCKS 1222ce0d7f9SMark Brown select ARCH_USE_SYM_ANNOTATIONS 123ce4a4e56SAndy Lutomirski select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 12481c22041SDaniel Borkmann select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 125c763ea26SIngo Molnar select ARCH_WANTS_DYNAMIC_TASK_STRUCT 12651c2ee6dSNick Desaulniers select ARCH_WANTS_NO_INSTR 12707431506SAnshuman Khandual select ARCH_WANT_GENERAL_HUGETLB 1283876d4a3SAlexandre Ghiti select ARCH_WANT_HUGE_PMD_SHARE 12959612b24SNathan Chancellor select ARCH_WANT_LD_ORPHAN_WARN 1300b376f1eSAneesh Kumar K.V select ARCH_WANT_OPTIMIZE_VMEMMAP if X86_64 13138d8b4e6SHuang Ying select ARCH_WANTS_THP_SWAP if X86_64 132b5f06f64SBalbir Singh select ARCH_HAS_PARANOID_L1D_FLUSH 13310916706SShile Zhang select BUILDTIME_TABLE_SORT 1346471b825SIngo Molnar select CLKEVT_I8253 1356471b825SIngo Molnar select CLOCKSOURCE_VALIDATE_LAST_CYCLE 1366471b825SIngo Molnar select CLOCKSOURCE_WATCHDOG 1377cf8f44aSAlexander Potapenko # Word-size accesses may read uninitialized data past the trailing \0 1387cf8f44aSAlexander Potapenko # in strings and cause false KMSAN reports. 1397cf8f44aSAlexander Potapenko select DCACHE_WORD_ACCESS if !KMSAN 1403aac3ebeSThomas Gleixner select DYNAMIC_SIGFRAME 14145471cd9SLinus Torvalds select EDAC_ATOMIC_SCRUB 14245471cd9SLinus Torvalds select EDAC_SUPPORT 1436471b825SIngo Molnar select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 1446471b825SIngo Molnar select GENERIC_CLOCKEVENTS_MIN_ADJUST 1456471b825SIngo Molnar select GENERIC_CMOS_UPDATE 1466471b825SIngo Molnar select GENERIC_CPU_AUTOPROBE 14761dc0f55SThomas Gleixner select GENERIC_CPU_VULNERABILITIES 1486471b825SIngo Molnar select GENERIC_EARLY_IOREMAP 14927d6b4d1SThomas Gleixner select GENERIC_ENTRY 1506471b825SIngo Molnar select GENERIC_IOMAP 151c7d6c9ddSThomas Gleixner select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 1520fa115daSThomas Gleixner select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 153ad7a929fSThomas Gleixner select GENERIC_IRQ_MIGRATION if SMP 1546471b825SIngo Molnar select GENERIC_IRQ_PROBE 155c201c917SThomas Gleixner select GENERIC_IRQ_RESERVATION_MODE 1566471b825SIngo Molnar select GENERIC_IRQ_SHOW 1576471b825SIngo Molnar select GENERIC_PENDING_IRQ if SMP 1582ae27137SSteven Price select GENERIC_PTDUMP 1596471b825SIngo Molnar select GENERIC_SMP_IDLE_THREAD 1606471b825SIngo Molnar select GENERIC_TIME_VSYSCALL 1617ac87074SVincenzo Frascino select GENERIC_GETTIMEOFDAY 162550a77a7SDmitry Safonov select GENERIC_VDSO_TIME_NS 1636ca297d4SPeter Zijlstra select GUP_GET_PXX_LOW_HIGH if X86_PAE 16417e5888eSHans de Goede select HARDIRQS_SW_RESEND 1657edaeb68SThomas Gleixner select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 166fcbfe812SNiklas Schnelle select HAS_IOPORT 1676471b825SIngo Molnar select HAVE_ACPI_APEI if ACPI 1686471b825SIngo Molnar select HAVE_ACPI_APEI_NMI if ACPI 1696471b825SIngo Molnar select HAVE_ALIGNED_STRUCT_PAGE if SLUB 1706471b825SIngo Molnar select HAVE_ARCH_AUDITSYSCALL 1716471b825SIngo Molnar select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 172eed1fceeSSong Liu select HAVE_ARCH_HUGE_VMALLOC if X86_64 1736471b825SIngo Molnar select HAVE_ARCH_JUMP_LABEL 174b34006c4SArd Biesheuvel select HAVE_ARCH_JUMP_LABEL_RELATIVE 175d17a1d97SAndrey Ryabinin select HAVE_ARCH_KASAN if X86_64 1760609ae01SDaniel Axtens select HAVE_ARCH_KASAN_VMALLOC if X86_64 1771dc0da6eSAlexander Potapenko select HAVE_ARCH_KFENCE 1784ca8cc8dSAlexander Potapenko select HAVE_ARCH_KMSAN if X86_64 1796471b825SIngo Molnar select HAVE_ARCH_KGDB 1809e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_BITS if MMU 1819e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 1821b028f78SDmitry Safonov select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 183271ca788SArd Biesheuvel select HAVE_ARCH_PREL32_RELOCATIONS 1846471b825SIngo Molnar select HAVE_ARCH_SECCOMP_FILTER 185f7d83c1cSKees Cook select HAVE_ARCH_THREAD_STRUCT_WHITELIST 186afaef01cSAlexander Popov select HAVE_ARCH_STACKLEAK 1876471b825SIngo Molnar select HAVE_ARCH_TRACEHOOK 1886471b825SIngo Molnar select HAVE_ARCH_TRANSPARENT_HUGEPAGE 189a00cc7d9SMatthew Wilcox select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 190b64d8d1eSPeter Xu select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 1917677f7fdSAxel Rasmussen select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 192e37e43a4SAndy Lutomirski select HAVE_ARCH_VMAP_STACK if X86_64 193fe950f60SKees Cook select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 194c763ea26SIngo Molnar select HAVE_ARCH_WITHIN_STACK_FRAMES 1952ff2b7ecSMasahiro Yamada select HAVE_ASM_MODVERSIONS 1966471b825SIngo Molnar select HAVE_CMPXCHG_DOUBLE 1976471b825SIngo Molnar select HAVE_CMPXCHG_LOCAL 19824a9c541SFrederic Weisbecker select HAVE_CONTEXT_TRACKING_USER if X86_64 19924a9c541SFrederic Weisbecker select HAVE_CONTEXT_TRACKING_USER_OFFSTACK if HAVE_CONTEXT_TRACKING_USER 2006471b825SIngo Molnar select HAVE_C_RECORDMCOUNT 20103f16cd0SJosh Poimboeuf select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL 202280981d6SSathvika Vasireddy select HAVE_OBJTOOL_NOP_MCOUNT if HAVE_OBJTOOL_MCOUNT 2034ed308c4SSteven Rostedt (Google) select HAVE_BUILDTIME_MCOUNT_SORT 2046471b825SIngo Molnar select HAVE_DEBUG_KMEMLEAK 2059c5a3621SAkinobu Mita select HAVE_DMA_CONTIGUOUS 206677aa9f7SSteven Rostedt select HAVE_DYNAMIC_FTRACE 20706aeaaeaSMasami Hiramatsu select HAVE_DYNAMIC_FTRACE_WITH_REGS 20802a474caSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 209562955feSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 210c316eb44SHeiko Carstens select HAVE_SAMPLE_FTRACE_DIRECT if X86_64 211503e4510SHeiko Carstens select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64 21203f5781bSWang YanQing select HAVE_EBPF_JIT 21358340a07SJohannes Berg select HAVE_EFFICIENT_UNALIGNED_ACCESS 2146630a8e5SChristoph Hellwig select HAVE_EISA 2155f56a5dfSJiri Slaby select HAVE_EXIT_THREAD 21667a929e0SChristoph Hellwig select HAVE_FAST_GUP 217644e0e8dSSteven Rostedt (VMware) select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 2186471b825SIngo Molnar select HAVE_FTRACE_MCOUNT_RECORD 219*d938ba17SDonglin Peng select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER 2204a30e4c9SSteven Rostedt (VMware) select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) 2216471b825SIngo Molnar select HAVE_FUNCTION_TRACER 2226b90bd4bSEmese Revfy select HAVE_GCC_PLUGINS 2230067f129SK.Prasad select HAVE_HW_BREAKPOINT 2246471b825SIngo Molnar select HAVE_IOREMAP_PROT 225624db9eaSThomas Gleixner select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 2266471b825SIngo Molnar select HAVE_IRQ_TIME_ACCOUNTING 2274ab7674fSJosh Poimboeuf select HAVE_JUMP_LABEL_HACK if HAVE_OBJTOOL 2286471b825SIngo Molnar select HAVE_KERNEL_BZIP2 2296471b825SIngo Molnar select HAVE_KERNEL_GZIP 2306471b825SIngo Molnar select HAVE_KERNEL_LZ4 2316471b825SIngo Molnar select HAVE_KERNEL_LZMA 2326471b825SIngo Molnar select HAVE_KERNEL_LZO 2336471b825SIngo Molnar select HAVE_KERNEL_XZ 234fb46d057SNick Terrell select HAVE_KERNEL_ZSTD 2356471b825SIngo Molnar select HAVE_KPROBES 2366471b825SIngo Molnar select HAVE_KPROBES_ON_FTRACE 237540adea3SMasami Hiramatsu select HAVE_FUNCTION_ERROR_INJECTION 2386471b825SIngo Molnar select HAVE_KRETPROBES 239f3a112c0SMasami Hiramatsu select HAVE_RETHOOK 2406471b825SIngo Molnar select HAVE_KVM 2416471b825SIngo Molnar select HAVE_LIVEPATCH if X86_64 2420102752eSFrederic Weisbecker select HAVE_MIXED_BREAKPOINTS_REGS 243ee9f8fceSJosh Poimboeuf select HAVE_MOD_ARCH_SPECIFIC 2449f132f7eSJoel Fernandes (Google) select HAVE_MOVE_PMD 245be37c98dSKalesh Singh select HAVE_MOVE_PUD 24622102f45SJosh Poimboeuf select HAVE_NOINSTR_HACK if HAVE_OBJTOOL 24742a0bb3fSPetr Mladek select HAVE_NMI 248489e355bSJosh Poimboeuf select HAVE_NOINSTR_VALIDATION if HAVE_OBJTOOL 24903f16cd0SJosh Poimboeuf select HAVE_OBJTOOL if X86_64 2506471b825SIngo Molnar select HAVE_OPTPROBES 2516471b825SIngo Molnar select HAVE_PCSPKR_PLATFORM 2526471b825SIngo Molnar select HAVE_PERF_EVENTS 253c01d4323SFrederic Weisbecker select HAVE_PERF_EVENTS_NMI 25492e5aae4SNicholas Piggin select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 255eb01d42aSChristoph Hellwig select HAVE_PCI 256c5e63197SJiri Olsa select HAVE_PERF_REGS 257c5ebcedbSJiri Olsa select HAVE_PERF_USER_STACK_DUMP 258ff2e6d72SPeter Zijlstra select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 2591e9fdf21SPeter Zijlstra select MMU_GATHER_MERGE_VMAS 26000998085SThomas Gleixner select HAVE_POSIX_CPU_TIMERS_TASK_WORK 2616471b825SIngo Molnar select HAVE_REGS_AND_STACK_ACCESS_API 26203f16cd0SJosh Poimboeuf select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC || STACK_VALIDATION 2633c88ee19SMasami Hiramatsu select HAVE_FUNCTION_ARG_ACCESS_API 2647ecd19cfSKefeng Wang select HAVE_SETUP_PER_CPU_AREA 265cd1a41ceSThomas Gleixner select HAVE_SOFTIRQ_ON_OWN_STACK 266d148eac0SMasahiro Yamada select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 26703f16cd0SJosh Poimboeuf select HAVE_STACK_VALIDATION if HAVE_OBJTOOL 268e6d6c071SJosh Poimboeuf select HAVE_STATIC_CALL 26903f16cd0SJosh Poimboeuf select HAVE_STATIC_CALL_INLINE if HAVE_OBJTOOL 27099cf983cSMark Rutland select HAVE_PREEMPT_DYNAMIC_CALL 271d6761b8fSMathieu Desnoyers select HAVE_RSEQ 27209498135SMiguel Ojeda select HAVE_RUST if X86_64 2736471b825SIngo Molnar select HAVE_SYSCALL_TRACEPOINTS 2745f3da8c0SJosh Poimboeuf select HAVE_UACCESS_VALIDATION if HAVE_OBJTOOL 2756471b825SIngo Molnar select HAVE_UNSTABLE_SCHED_CLOCK 2767c68af6eSAvi Kivity select HAVE_USER_RETURN_NOTIFIER 2777ac87074SVincenzo Frascino select HAVE_GENERIC_VDSO 27805736e4aSThomas Gleixner select HOTPLUG_SMT if SMP 279c0185808SThomas Gleixner select IRQ_FORCED_THREADING 2807ecd19cfSKefeng Wang select NEED_PER_CPU_EMBED_FIRST_CHUNK 2817ecd19cfSKefeng Wang select NEED_PER_CPU_PAGE_FIRST_CHUNK 28286596f0aSChristoph Hellwig select NEED_SG_DMA_LENGTH 2832eac9c2dSChristoph Hellwig select PCI_DOMAINS if PCI 284625210cfSSinan Kaya select PCI_LOCKLESS_CONFIG if PCI 2856471b825SIngo Molnar select PERF_EVENTS 2863195ef59SPrarit Bhargava select RTC_LIB 287d6faca40SArnd Bergmann select RTC_MC146818_LIB 2886471b825SIngo Molnar select SPARSE_IRQ 2896471b825SIngo Molnar select SYSCTL_EXCEPTION_TRACE 29015f4eae7SAndy Lutomirski select THREAD_INFO_IN_TASK 2914aae683fSMasahiro Yamada select TRACE_IRQFLAGS_SUPPORT 2924510bffbSMark Rutland select TRACE_IRQFLAGS_NMI_SUPPORT 2936471b825SIngo Molnar select USER_STACKTRACE_SUPPORT 2943b02a051SIngo Molnar select HAVE_ARCH_KCSAN if X86_64 2956471b825SIngo Molnar select X86_FEATURE_NAMES if PROC_FS 2960c608dadSAubrey Li select PROC_PID_ARCH_STATUS if PROC_FS 29750468e43SJarkko Sakkinen select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX 298d49a0626SPeter Zijlstra select FUNCTION_ALIGNMENT_16B if X86_64 || X86_ALIGNMENT_16 299d49a0626SPeter Zijlstra select FUNCTION_ALIGNMENT_4B 3009e2b4be3SNayna Jain imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 301ceea991aSJiri Olsa select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 3027d8330a5SBalbir Singh 303ba7e4d13SIngo Molnarconfig INSTRUCTION_DECODER 3043120e25eSJan Beulich def_bool y 3053120e25eSJan Beulich depends on KPROBES || PERF_EVENTS || UPROBES 306ba7e4d13SIngo Molnar 30751b26adaSLinus Torvaldsconfig OUTPUT_FORMAT 30851b26adaSLinus Torvalds string 30951b26adaSLinus Torvalds default "elf32-i386" if X86_32 31051b26adaSLinus Torvalds default "elf64-x86-64" if X86_64 31151b26adaSLinus Torvalds 3128d5fffb9SSam Ravnborgconfig LOCKDEP_SUPPORT 3133c2362e6SHarvey Harrison def_bool y 3148d5fffb9SSam Ravnborg 3158d5fffb9SSam Ravnborgconfig STACKTRACE_SUPPORT 3163c2362e6SHarvey Harrison def_bool y 3178d5fffb9SSam Ravnborg 3188d5fffb9SSam Ravnborgconfig MMU 3193c2362e6SHarvey Harrison def_bool y 3208d5fffb9SSam Ravnborg 3219e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MIN 3229e08f57dSDaniel Cashman default 28 if 64BIT 3239e08f57dSDaniel Cashman default 8 3249e08f57dSDaniel Cashman 3259e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MAX 3269e08f57dSDaniel Cashman default 32 if 64BIT 3279e08f57dSDaniel Cashman default 16 3289e08f57dSDaniel Cashman 3299e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MIN 3309e08f57dSDaniel Cashman default 8 3319e08f57dSDaniel Cashman 3329e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MAX 3339e08f57dSDaniel Cashman default 16 3349e08f57dSDaniel Cashman 3358d5fffb9SSam Ravnborgconfig SBUS 3368d5fffb9SSam Ravnborg bool 3378d5fffb9SSam Ravnborg 3388d5fffb9SSam Ravnborgconfig GENERIC_ISA_DMA 3393120e25eSJan Beulich def_bool y 3403120e25eSJan Beulich depends on ISA_DMA_API 3418d5fffb9SSam Ravnborg 342d911c67eSAlexander Potapenkoconfig GENERIC_CSUM 343d911c67eSAlexander Potapenko bool 344d911c67eSAlexander Potapenko default y if KMSAN || KASAN 345d911c67eSAlexander Potapenko 3468d5fffb9SSam Ravnborgconfig GENERIC_BUG 3473c2362e6SHarvey Harrison def_bool y 3488d5fffb9SSam Ravnborg depends on BUG 349b93a531eSJan Beulich select GENERIC_BUG_RELATIVE_POINTERS if X86_64 350b93a531eSJan Beulich 351b93a531eSJan Beulichconfig GENERIC_BUG_RELATIVE_POINTERS 352b93a531eSJan Beulich bool 3538d5fffb9SSam Ravnborg 3548d5fffb9SSam Ravnborgconfig ARCH_MAY_HAVE_PC_FDC 3553120e25eSJan Beulich def_bool y 3563120e25eSJan Beulich depends on ISA_DMA_API 3578d5fffb9SSam Ravnborg 3581032c0baSSam Ravnborgconfig GENERIC_CALIBRATE_DELAY 3591032c0baSSam Ravnborg def_bool y 3601032c0baSSam Ravnborg 3619a0b8415Svenkatesh.pallipadi@intel.comconfig ARCH_HAS_CPU_RELAX 3629a0b8415Svenkatesh.pallipadi@intel.com def_bool y 3638d5fffb9SSam Ravnborg 364801e4062SJohannes Bergconfig ARCH_HIBERNATION_POSSIBLE 365801e4062SJohannes Berg def_bool y 366801e4062SJohannes Berg 367f4cb5700SJohannes Bergconfig ARCH_SUSPEND_POSSIBLE 368f4cb5700SJohannes Berg def_bool y 369f4cb5700SJohannes Berg 3708d5fffb9SSam Ravnborgconfig AUDIT_ARCH 371e0fd24a3SJan Beulich def_bool y if X86_64 3728d5fffb9SSam Ravnborg 373d6f2d75aSAndrey Ryabininconfig KASAN_SHADOW_OFFSET 374d6f2d75aSAndrey Ryabinin hex 375d6f2d75aSAndrey Ryabinin depends on KASAN 376d6f2d75aSAndrey Ryabinin default 0xdffffc0000000000 377d6f2d75aSAndrey Ryabinin 37869575d38SShane Wangconfig HAVE_INTEL_TXT 37969575d38SShane Wang def_bool y 3806ea30386SKees Cook depends on INTEL_IOMMU && ACPI 38169575d38SShane Wang 3826b0c3d44SSam Ravnborgconfig X86_32_SMP 3836b0c3d44SSam Ravnborg def_bool y 3846b0c3d44SSam Ravnborg depends on X86_32 && SMP 3856b0c3d44SSam Ravnborg 3866b0c3d44SSam Ravnborgconfig X86_64_SMP 3876b0c3d44SSam Ravnborg def_bool y 3886b0c3d44SSam Ravnborg depends on X86_64 && SMP 3896b0c3d44SSam Ravnborg 3902b144498SSrikar Dronamrajuconfig ARCH_SUPPORTS_UPROBES 3912b144498SSrikar Dronamraju def_bool y 3922b144498SSrikar Dronamraju 393d20642f0SRob Herringconfig FIX_EARLYCON_MEM 394d20642f0SRob Herring def_bool y 395d20642f0SRob Herring 39694d49eb3SKirill A. Shutemovconfig DYNAMIC_PHYSICAL_MASK 39794d49eb3SKirill A. Shutemov bool 39894d49eb3SKirill A. Shutemov 39998233368SKirill A. Shutemovconfig PGTABLE_LEVELS 40098233368SKirill A. Shutemov int 40177ef56e4SKirill A. Shutemov default 5 if X86_5LEVEL 40298233368SKirill A. Shutemov default 4 if X86_64 40398233368SKirill A. Shutemov default 3 if X86_PAE 40498233368SKirill A. Shutemov default 2 40598233368SKirill A. Shutemov 4062a61f474SMasahiro Yamadaconfig CC_HAS_SANE_STACKPROTECTOR 4072a61f474SMasahiro Yamada bool 4081b866781SNathan Chancellor default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT 4091b866781SNathan Chancellor default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) 4102a61f474SMasahiro Yamada help 4112a61f474SMasahiro Yamada We have to make sure stack protector is unconditionally disabled if 4123fb0fdb3SAndy Lutomirski the compiler produces broken code or if it does not let us control 4133fb0fdb3SAndy Lutomirski the segment on 32-bit kernels. 4142a61f474SMasahiro Yamada 415506f1d07SSam Ravnborgmenu "Processor type and features" 416506f1d07SSam Ravnborg 417506f1d07SSam Ravnborgconfig SMP 418506f1d07SSam Ravnborg bool "Symmetric multi-processing support" 419a7f7f624SMasahiro Yamada help 420506f1d07SSam Ravnborg This enables support for systems with more than one CPU. If you have 4214a474157SRobert Graffham a system with only one CPU, say N. If you have a system with more 4224a474157SRobert Graffham than one CPU, say Y. 423506f1d07SSam Ravnborg 4244a474157SRobert Graffham If you say N here, the kernel will run on uni- and multiprocessor 425506f1d07SSam Ravnborg machines, but will use only one CPU of a multiprocessor machine. If 426506f1d07SSam Ravnborg you say Y here, the kernel will run on many, but not all, 4274a474157SRobert Graffham uniprocessor machines. On a uniprocessor machine, the kernel 428506f1d07SSam Ravnborg will run faster if you say N here. 429506f1d07SSam Ravnborg 430506f1d07SSam Ravnborg Note that if you say Y here and choose architecture "586" or 431506f1d07SSam Ravnborg "Pentium" under "Processor family", the kernel will not work on 486 432506f1d07SSam Ravnborg architectures. Similarly, multiprocessor kernels for the "PPro" 433506f1d07SSam Ravnborg architecture may not work on all Pentium based boards. 434506f1d07SSam Ravnborg 435506f1d07SSam Ravnborg People using multiprocessor machines who say Y here should also say 436506f1d07SSam Ravnborg Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 437506f1d07SSam Ravnborg Management" code will be disabled if you say Y here. 438506f1d07SSam Ravnborg 439ff61f079SJonathan Corbet See also <file:Documentation/arch/x86/i386/IO-APIC.rst>, 4404f4cfa6cSMauro Carvalho Chehab <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 441506f1d07SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 442506f1d07SSam Ravnborg 443506f1d07SSam Ravnborg If you don't know what to do here, say N. 444506f1d07SSam Ravnborg 4459def39beSJosh Triplettconfig X86_FEATURE_NAMES 4469def39beSJosh Triplett bool "Processor feature human-readable names" if EMBEDDED 4479def39beSJosh Triplett default y 448a7f7f624SMasahiro Yamada help 4499def39beSJosh Triplett This option compiles in a table of x86 feature bits and corresponding 4509def39beSJosh Triplett names. This is required to support /proc/cpuinfo and a few kernel 4519def39beSJosh Triplett messages. You can disable this to save space, at the expense of 4529def39beSJosh Triplett making those few kernel messages show numeric feature bits instead. 4539def39beSJosh Triplett 4549def39beSJosh Triplett If in doubt, say Y. 4559def39beSJosh Triplett 45606cd9a7dSYinghai Luconfig X86_X2APIC 45706cd9a7dSYinghai Lu bool "Support x2apic" 45819e3d60dSJan Kiszka depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 459a7f7f624SMasahiro Yamada help 46006cd9a7dSYinghai Lu This enables x2apic support on CPUs that have this feature. 46106cd9a7dSYinghai Lu 46206cd9a7dSYinghai Lu This allows 32-bit apic IDs (so it can support very large systems), 46306cd9a7dSYinghai Lu and accesses the local apic via MSRs not via mmio. 46406cd9a7dSYinghai Lu 465b8d1d163SDaniel Sneddon Some Intel systems circa 2022 and later are locked into x2APIC mode 466b8d1d163SDaniel Sneddon and can not fall back to the legacy APIC modes if SGX or TDX are 467e3998434SMateusz Jończyk enabled in the BIOS. They will boot with very reduced functionality 468e3998434SMateusz Jończyk without enabling this option. 469b8d1d163SDaniel Sneddon 47006cd9a7dSYinghai Lu If you don't know what to do here, say N. 47106cd9a7dSYinghai Lu 4726695c85bSYinghai Luconfig X86_MPPARSE 4734590d98fSAndy Shevchenko bool "Enable MPS table" if ACPI 4747a527688SJan Beulich default y 4755ab74722SIngo Molnar depends on X86_LOCAL_APIC 476a7f7f624SMasahiro Yamada help 4776695c85bSYinghai Lu For old smp systems that do not have proper acpi support. Newer systems 4786695c85bSYinghai Lu (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 4796695c85bSYinghai Lu 480ddd70cf9SJun Nakajimaconfig GOLDFISH 481ddd70cf9SJun Nakajima def_bool y 482ddd70cf9SJun Nakajima depends on X86_GOLDFISH 483ddd70cf9SJun Nakajima 484e6d42931SJohannes Weinerconfig X86_CPU_RESCTRL 485e6d42931SJohannes Weiner bool "x86 CPU resource control support" 4866fe07ce3SBabu Moger depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 48759fe5a77SThomas Gleixner select KERNFS 488e79f15a4SChen Yu select PROC_CPU_RESCTRL if PROC_FS 48978e99b4aSFenghua Yu help 490e6d42931SJohannes Weiner Enable x86 CPU resource control support. 4916fe07ce3SBabu Moger 4926fe07ce3SBabu Moger Provide support for the allocation and monitoring of system resources 4936fe07ce3SBabu Moger usage by the CPU. 4946fe07ce3SBabu Moger 4956fe07ce3SBabu Moger Intel calls this Intel Resource Director Technology 4966fe07ce3SBabu Moger (Intel(R) RDT). More information about RDT can be found in the 4976fe07ce3SBabu Moger Intel x86 Architecture Software Developer Manual. 4986fe07ce3SBabu Moger 4996fe07ce3SBabu Moger AMD calls this AMD Platform Quality of Service (AMD QoS). 5006fe07ce3SBabu Moger More information about AMD QoS can be found in the AMD64 Technology 5016fe07ce3SBabu Moger Platform Quality of Service Extensions manual. 50278e99b4aSFenghua Yu 50378e99b4aSFenghua Yu Say N if unsure. 50478e99b4aSFenghua Yu 5058425091fSRavikiran G Thirumalaiif X86_32 506a0d0bb4dSRandy Dunlapconfig X86_BIGSMP 507a0d0bb4dSRandy Dunlap bool "Support for big SMP systems with more than 8 CPUs" 508a0d0bb4dSRandy Dunlap depends on SMP 509a7f7f624SMasahiro Yamada help 510e133f6eaSRandy Dunlap This option is needed for the systems that have more than 8 CPUs. 511a0d0bb4dSRandy Dunlap 512c5c606d9SRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 513c5c606d9SRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 514c5c606d9SRavikiran G Thirumalai default y 515a7f7f624SMasahiro Yamada help 51606ac8346SIngo Molnar If you disable this option then the kernel will only support 51706ac8346SIngo Molnar standard PC platforms. (which covers the vast majority of 51806ac8346SIngo Molnar systems out there.) 51906ac8346SIngo Molnar 5208425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5218425091fSRavikiran G Thirumalai for the following (non-PC) 32 bit x86 platforms: 522cb7b8023SBen Hutchings Goldfish (Android emulator) 5238425091fSRavikiran G Thirumalai AMD Elan 5248425091fSRavikiran G Thirumalai RDC R-321x SoC 5258425091fSRavikiran G Thirumalai SGI 320/540 (Visual Workstation) 52683125a3aSAlessandro Rubini STA2X11-based (e.g. Northville) 5273f4110a4SThomas Gleixner Moorestown MID devices 52806ac8346SIngo Molnar 52906ac8346SIngo Molnar If you have one of these systems, or if you want to build a 53006ac8346SIngo Molnar generic distribution kernel, say Y here - otherwise say N. 531758cd94aSJuerg Haefligerendif # X86_32 53206ac8346SIngo Molnar 5338425091fSRavikiran G Thirumalaiif X86_64 5348425091fSRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 5358425091fSRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 5368425091fSRavikiran G Thirumalai default y 537a7f7f624SMasahiro Yamada help 5388425091fSRavikiran G Thirumalai If you disable this option then the kernel will only support 5398425091fSRavikiran G Thirumalai standard PC platforms. (which covers the vast majority of 5408425091fSRavikiran G Thirumalai systems out there.) 5418425091fSRavikiran G Thirumalai 5428425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5438425091fSRavikiran G Thirumalai for the following (non-PC) 64 bit x86 platforms: 54444b111b5SSteffen Persvold Numascale NumaChip 5458425091fSRavikiran G Thirumalai ScaleMP vSMP 5468425091fSRavikiran G Thirumalai SGI Ultraviolet 5478425091fSRavikiran G Thirumalai 5488425091fSRavikiran G Thirumalai If you have one of these systems, or if you want to build a 5498425091fSRavikiran G Thirumalai generic distribution kernel, say Y here - otherwise say N. 550758cd94aSJuerg Haefligerendif # X86_64 551c5c606d9SRavikiran G Thirumalai# This is an alphabetically sorted list of 64 bit extended platforms 552c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 55344b111b5SSteffen Persvoldconfig X86_NUMACHIP 55444b111b5SSteffen Persvold bool "Numascale NumaChip" 55544b111b5SSteffen Persvold depends on X86_64 55644b111b5SSteffen Persvold depends on X86_EXTENDED_PLATFORM 55744b111b5SSteffen Persvold depends on NUMA 55844b111b5SSteffen Persvold depends on SMP 55944b111b5SSteffen Persvold depends on X86_X2APIC 560f9726bfdSDaniel J Blueman depends on PCI_MMCONFIG 561a7f7f624SMasahiro Yamada help 56244b111b5SSteffen Persvold Adds support for Numascale NumaChip large-SMP systems. Needed to 56344b111b5SSteffen Persvold enable more than ~168 cores. 56444b111b5SSteffen Persvold If you don't have one of these, you should say N here. 56503b48632SNick Piggin 5666a48565eSIngo Molnarconfig X86_VSMP 567c5c606d9SRavikiran G Thirumalai bool "ScaleMP vSMP" 5686276a074SBorislav Petkov select HYPERVISOR_GUEST 5696a48565eSIngo Molnar select PARAVIRT 5706a48565eSIngo Molnar depends on X86_64 && PCI 571c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 572ead91d4bSShai Fultheim depends on SMP 573a7f7f624SMasahiro Yamada help 5746a48565eSIngo Molnar Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 5756a48565eSIngo Molnar supposed to run on these EM64T-based machines. Only choose this option 5766a48565eSIngo Molnar if you have one of these machines. 5776a48565eSIngo Molnar 578c5c606d9SRavikiran G Thirumalaiconfig X86_UV 579c5c606d9SRavikiran G Thirumalai bool "SGI Ultraviolet" 580c5c606d9SRavikiran G Thirumalai depends on X86_64 581c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 58254c28d29SJack Steiner depends on NUMA 5831ecb4ae5SAndrew Morton depends on EFI 584c2209ea5SIngo Molnar depends on KEXEC_CORE 5859d6c26e7SSuresh Siddha depends on X86_X2APIC 5861222e564SIngo Molnar depends on PCI 587a7f7f624SMasahiro Yamada help 588c5c606d9SRavikiran G Thirumalai This option is needed in order to support SGI Ultraviolet systems. 589c5c606d9SRavikiran G Thirumalai If you don't have one of these, you should say N here. 590c5c606d9SRavikiran G Thirumalai 591c5c606d9SRavikiran G Thirumalai# Following is an alphabetically sorted list of 32 bit extended platforms 592c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 593506f1d07SSam Ravnborg 594ddd70cf9SJun Nakajimaconfig X86_GOLDFISH 595ddd70cf9SJun Nakajima bool "Goldfish (Virtual Platform)" 596cb7b8023SBen Hutchings depends on X86_EXTENDED_PLATFORM 597a7f7f624SMasahiro Yamada help 598ddd70cf9SJun Nakajima Enable support for the Goldfish virtual platform used primarily 599ddd70cf9SJun Nakajima for Android development. Unless you are building for the Android 600ddd70cf9SJun Nakajima Goldfish emulator say N here. 601ddd70cf9SJun Nakajima 602c751e17bSThomas Gleixnerconfig X86_INTEL_CE 603c751e17bSThomas Gleixner bool "CE4100 TV platform" 604c751e17bSThomas Gleixner depends on PCI 605c751e17bSThomas Gleixner depends on PCI_GODIRECT 6066084a6e2SJiang Liu depends on X86_IO_APIC 607c751e17bSThomas Gleixner depends on X86_32 608c751e17bSThomas Gleixner depends on X86_EXTENDED_PLATFORM 60937bc9f50SDirk Brandewie select X86_REBOOTFIXUPS 610da6b737bSSebastian Andrzej Siewior select OF 611da6b737bSSebastian Andrzej Siewior select OF_EARLY_FLATTREE 612a7f7f624SMasahiro Yamada help 613c751e17bSThomas Gleixner Select for the Intel CE media processor (CE4100) SOC. 614c751e17bSThomas Gleixner This option compiles in support for the CE4100 SOC for settop 615c751e17bSThomas Gleixner boxes and media devices. 616c751e17bSThomas Gleixner 6174cb9b00fSDavid Cohenconfig X86_INTEL_MID 61843605ef1SAlan Cox bool "Intel MID platform support" 61943605ef1SAlan Cox depends on X86_EXTENDED_PLATFORM 620edc6bc78SDavid Cohen depends on X86_PLATFORM_DEVICES 6211ea7c673SAlan Cox depends on PCI 6223fda5bb4SAndy Shevchenko depends on X86_64 || (PCI_GOANY && X86_32) 6231ea7c673SAlan Cox depends on X86_IO_APIC 6244cb9b00fSDavid Cohen select I2C 6257c9c3a1eSAlan Cox select DW_APB_TIMER 62654b34aa0SMika Westerberg select INTEL_SCU_PCI 627a7f7f624SMasahiro Yamada help 6284cb9b00fSDavid Cohen Select to build a kernel capable of supporting Intel MID (Mobile 6294cb9b00fSDavid Cohen Internet Device) platform systems which do not have the PCI legacy 6304cb9b00fSDavid Cohen interfaces. If you are building for a PC class system say N here. 6311ea7c673SAlan Cox 6324cb9b00fSDavid Cohen Intel MID platforms are based on an Intel processor and chipset which 6334cb9b00fSDavid Cohen consume less power than most of the x86 derivatives. 63443605ef1SAlan Cox 6358bbc2a13SBryan O'Donoghueconfig X86_INTEL_QUARK 6368bbc2a13SBryan O'Donoghue bool "Intel Quark platform support" 6378bbc2a13SBryan O'Donoghue depends on X86_32 6388bbc2a13SBryan O'Donoghue depends on X86_EXTENDED_PLATFORM 6398bbc2a13SBryan O'Donoghue depends on X86_PLATFORM_DEVICES 6408bbc2a13SBryan O'Donoghue depends on X86_TSC 6418bbc2a13SBryan O'Donoghue depends on PCI 6428bbc2a13SBryan O'Donoghue depends on PCI_GOANY 6438bbc2a13SBryan O'Donoghue depends on X86_IO_APIC 6448bbc2a13SBryan O'Donoghue select IOSF_MBI 6458bbc2a13SBryan O'Donoghue select INTEL_IMR 6469ab6eb51SAndy Shevchenko select COMMON_CLK 647a7f7f624SMasahiro Yamada help 6488bbc2a13SBryan O'Donoghue Select to include support for Quark X1000 SoC. 6498bbc2a13SBryan O'Donoghue Say Y here if you have a Quark based system such as the Arduino 6508bbc2a13SBryan O'Donoghue compatible Intel Galileo. 6518bbc2a13SBryan O'Donoghue 6523d48aab1SMika Westerbergconfig X86_INTEL_LPSS 6533d48aab1SMika Westerberg bool "Intel Low Power Subsystem Support" 6545962dd22SSinan Kaya depends on X86 && ACPI && PCI 6553d48aab1SMika Westerberg select COMMON_CLK 6560f531431SMathias Nyman select PINCTRL 657eebb3e8dSAndy Shevchenko select IOSF_MBI 658a7f7f624SMasahiro Yamada help 6593d48aab1SMika Westerberg Select to build support for Intel Low Power Subsystem such as 6603d48aab1SMika Westerberg found on Intel Lynxpoint PCH. Selecting this option enables 6610f531431SMathias Nyman things like clock tree (common clock framework) and pincontrol 6620f531431SMathias Nyman which are needed by the LPSS peripheral drivers. 6633d48aab1SMika Westerberg 66492082a88SKen Xueconfig X86_AMD_PLATFORM_DEVICE 66592082a88SKen Xue bool "AMD ACPI2Platform devices support" 66692082a88SKen Xue depends on ACPI 66792082a88SKen Xue select COMMON_CLK 66892082a88SKen Xue select PINCTRL 669a7f7f624SMasahiro Yamada help 67092082a88SKen Xue Select to interpret AMD specific ACPI device to platform device 67192082a88SKen Xue such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 67292082a88SKen Xue I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 67392082a88SKen Xue implemented under PINCTRL subsystem. 67492082a88SKen Xue 675ced3ce76SDavid E. Boxconfig IOSF_MBI 676ced3ce76SDavid E. Box tristate "Intel SoC IOSF Sideband support for SoC platforms" 677ced3ce76SDavid E. Box depends on PCI 678a7f7f624SMasahiro Yamada help 679ced3ce76SDavid E. Box This option enables sideband register access support for Intel SoC 680ced3ce76SDavid E. Box platforms. On these platforms the IOSF sideband is used in lieu of 681ced3ce76SDavid E. Box MSR's for some register accesses, mostly but not limited to thermal 682ced3ce76SDavid E. Box and power. Drivers may query the availability of this device to 683ced3ce76SDavid E. Box determine if they need the sideband in order to work on these 684ced3ce76SDavid E. Box platforms. The sideband is available on the following SoC products. 685ced3ce76SDavid E. Box This list is not meant to be exclusive. 686ced3ce76SDavid E. Box - BayTrail 687ced3ce76SDavid E. Box - Braswell 688ced3ce76SDavid E. Box - Quark 689ced3ce76SDavid E. Box 690ced3ce76SDavid E. Box You should say Y if you are running a kernel on one of these SoC's. 691ced3ce76SDavid E. Box 692ed2226bdSDavid E. Boxconfig IOSF_MBI_DEBUG 693ed2226bdSDavid E. Box bool "Enable IOSF sideband access through debugfs" 694ed2226bdSDavid E. Box depends on IOSF_MBI && DEBUG_FS 695a7f7f624SMasahiro Yamada help 696ed2226bdSDavid E. Box Select this option to expose the IOSF sideband access registers (MCR, 697ed2226bdSDavid E. Box MDR, MCRX) through debugfs to write and read register information from 698ed2226bdSDavid E. Box different units on the SoC. This is most useful for obtaining device 699ed2226bdSDavid E. Box state information for debug and analysis. As this is a general access 700ed2226bdSDavid E. Box mechanism, users of this option would have specific knowledge of the 701ed2226bdSDavid E. Box device they want to access. 702ed2226bdSDavid E. Box 703ed2226bdSDavid E. Box If you don't require the option or are in doubt, say N. 704ed2226bdSDavid E. Box 705c5c606d9SRavikiran G Thirumalaiconfig X86_RDC321X 706c5c606d9SRavikiran G Thirumalai bool "RDC R-321x SoC" 707506f1d07SSam Ravnborg depends on X86_32 708c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 709c5c606d9SRavikiran G Thirumalai select M486 710c5c606d9SRavikiran G Thirumalai select X86_REBOOTFIXUPS 711a7f7f624SMasahiro Yamada help 712c5c606d9SRavikiran G Thirumalai This option is needed for RDC R-321x system-on-chip, also known 713c5c606d9SRavikiran G Thirumalai as R-8610-(G). 714c5c606d9SRavikiran G Thirumalai If you don't have one of these chips, you should say N here. 715c5c606d9SRavikiran G Thirumalai 716e0c7ae37SIngo Molnarconfig X86_32_NON_STANDARD 7179c398017SIngo Molnar bool "Support non-standard 32-bit SMP architectures" 7189c398017SIngo Molnar depends on X86_32 && SMP 719c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 720a7f7f624SMasahiro Yamada help 721b5660ba7SH. Peter Anvin This option compiles in the bigsmp and STA2X11 default 722b5660ba7SH. Peter Anvin subarchitectures. It is intended for a generic binary 723b5660ba7SH. Peter Anvin kernel. If you select them all, kernel will probe it one by 724b5660ba7SH. Peter Anvin one and will fallback to default. 725d49c4288SYinghai Lu 726c5c606d9SRavikiran G Thirumalai# Alphabetically sorted list of Non standard 32 bit platforms 727d49c4288SYinghai Lu 728d949f36fSLinus Torvaldsconfig X86_SUPPORTS_MEMORY_FAILURE 7296fc108a0SJan Beulich def_bool y 730d949f36fSLinus Torvalds # MCE code calls memory_failure(): 731d949f36fSLinus Torvalds depends on X86_MCE 732d949f36fSLinus Torvalds # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 733d949f36fSLinus Torvalds # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 734d949f36fSLinus Torvalds depends on X86_64 || !SPARSEMEM 735d949f36fSLinus Torvalds select ARCH_SUPPORTS_MEMORY_FAILURE 736d949f36fSLinus Torvalds 73783125a3aSAlessandro Rubiniconfig STA2X11 73883125a3aSAlessandro Rubini bool "STA2X11 Companion Chip Support" 73983125a3aSAlessandro Rubini depends on X86_32_NON_STANDARD && PCI 74083125a3aSAlessandro Rubini select SWIOTLB 74183125a3aSAlessandro Rubini select MFD_STA2X11 7420145071bSLinus Walleij select GPIOLIB 743a7f7f624SMasahiro Yamada help 74483125a3aSAlessandro Rubini This adds support for boards based on the STA2X11 IO-Hub, 74583125a3aSAlessandro Rubini a.k.a. "ConneXt". The chip is used in place of the standard 74683125a3aSAlessandro Rubini PC chipset, so all "standard" peripherals are missing. If this 74783125a3aSAlessandro Rubini option is selected the kernel will still be able to boot on 74883125a3aSAlessandro Rubini standard PC machines. 74983125a3aSAlessandro Rubini 75082148d1dSShérabconfig X86_32_IRIS 75182148d1dSShérab tristate "Eurobraille/Iris poweroff module" 75282148d1dSShérab depends on X86_32 753a7f7f624SMasahiro Yamada help 75482148d1dSShérab The Iris machines from EuroBraille do not have APM or ACPI support 75582148d1dSShérab to shut themselves down properly. A special I/O sequence is 75682148d1dSShérab needed to do so, which is what this module does at 75782148d1dSShérab kernel shutdown. 75882148d1dSShérab 75982148d1dSShérab This is only for Iris machines from EuroBraille. 76082148d1dSShérab 76182148d1dSShérab If unused, say N. 76282148d1dSShérab 763ae1e9130SIngo Molnarconfig SCHED_OMIT_FRAME_POINTER 7643c2362e6SHarvey Harrison def_bool y 7653c2362e6SHarvey Harrison prompt "Single-depth WCHAN output" 766a87d0914SKen Chen depends on X86 767a7f7f624SMasahiro Yamada help 768506f1d07SSam Ravnborg Calculate simpler /proc/<PID>/wchan values. If this option 769506f1d07SSam Ravnborg is disabled then wchan values will recurse back to the 770506f1d07SSam Ravnborg caller function. This provides more accurate wchan values, 771506f1d07SSam Ravnborg at the expense of slightly more scheduling overhead. 772506f1d07SSam Ravnborg 773506f1d07SSam Ravnborg If in doubt, say "Y". 774506f1d07SSam Ravnborg 7756276a074SBorislav Petkovmenuconfig HYPERVISOR_GUEST 7766276a074SBorislav Petkov bool "Linux guest support" 777a7f7f624SMasahiro Yamada help 7786276a074SBorislav Petkov Say Y here to enable options for running Linux under various hyper- 7796276a074SBorislav Petkov visors. This option enables basic hypervisor detection and platform 7806276a074SBorislav Petkov setup. 781506f1d07SSam Ravnborg 7826276a074SBorislav Petkov If you say N, all options in this submenu will be skipped and 7836276a074SBorislav Petkov disabled, and Linux guest support won't be built in. 784506f1d07SSam Ravnborg 7856276a074SBorislav Petkovif HYPERVISOR_GUEST 786506f1d07SSam Ravnborg 787e61bd94aSEduardo Pereira Habkostconfig PARAVIRT 788e61bd94aSEduardo Pereira Habkost bool "Enable paravirtualization code" 789a0e2bf7cSJuergen Gross depends on HAVE_STATIC_CALL 790a7f7f624SMasahiro Yamada help 791e61bd94aSEduardo Pereira Habkost This changes the kernel so it can modify itself when it is run 792e61bd94aSEduardo Pereira Habkost under a hypervisor, potentially improving performance significantly 793e61bd94aSEduardo Pereira Habkost over full virtualization. However, when run without a hypervisor 794e61bd94aSEduardo Pereira Habkost the kernel is theoretically slower and slightly larger. 795e61bd94aSEduardo Pereira Habkost 796c00a280aSJuergen Grossconfig PARAVIRT_XXL 797c00a280aSJuergen Gross bool 798c00a280aSJuergen Gross 7996276a074SBorislav Petkovconfig PARAVIRT_DEBUG 8006276a074SBorislav Petkov bool "paravirt-ops debugging" 8016276a074SBorislav Petkov depends on PARAVIRT && DEBUG_KERNEL 802a7f7f624SMasahiro Yamada help 8036276a074SBorislav Petkov Enable to debug paravirt_ops internals. Specifically, BUG if 8046276a074SBorislav Petkov a paravirt_op is missing when it is called. 8056276a074SBorislav Petkov 806b4ecc126SJeremy Fitzhardingeconfig PARAVIRT_SPINLOCKS 807b4ecc126SJeremy Fitzhardinge bool "Paravirtualization layer for spinlocks" 8086ea30386SKees Cook depends on PARAVIRT && SMP 809a7f7f624SMasahiro Yamada help 810b4ecc126SJeremy Fitzhardinge Paravirtualized spinlocks allow a pvops backend to replace the 811b4ecc126SJeremy Fitzhardinge spinlock implementation with something virtualization-friendly 812b4ecc126SJeremy Fitzhardinge (for example, block the virtual CPU rather than spinning). 813b4ecc126SJeremy Fitzhardinge 8144c4e4f61SRaghavendra K T It has a minimal impact on native kernels and gives a nice performance 8154c4e4f61SRaghavendra K T benefit on paravirtualized KVM / Xen kernels. 816b4ecc126SJeremy Fitzhardinge 8174c4e4f61SRaghavendra K T If you are unsure how to answer this question, answer Y. 818b4ecc126SJeremy Fitzhardinge 819ecca2502SZhao Yakuiconfig X86_HV_CALLBACK_VECTOR 820ecca2502SZhao Yakui def_bool n 821ecca2502SZhao Yakui 8226276a074SBorislav Petkovsource "arch/x86/xen/Kconfig" 8236276a074SBorislav Petkov 8246276a074SBorislav Petkovconfig KVM_GUEST 8256276a074SBorislav Petkov bool "KVM Guest support (including kvmclock)" 8266276a074SBorislav Petkov depends on PARAVIRT 8276276a074SBorislav Petkov select PARAVIRT_CLOCK 828a1c4423bSMarcelo Tosatti select ARCH_CPUIDLE_HALTPOLL 829b1d40575SVitaly Kuznetsov select X86_HV_CALLBACK_VECTOR 8306276a074SBorislav Petkov default y 831a7f7f624SMasahiro Yamada help 8326276a074SBorislav Petkov This option enables various optimizations for running under the KVM 8336276a074SBorislav Petkov hypervisor. It includes a paravirtualized clock, so that instead 8346276a074SBorislav Petkov of relying on a PIT (or probably other) emulation by the 8356276a074SBorislav Petkov underlying device model, the host provides the guest with 8366276a074SBorislav Petkov timing infrastructure such as time of day, and system time 8376276a074SBorislav Petkov 838a1c4423bSMarcelo Tosatticonfig ARCH_CPUIDLE_HALTPOLL 839a1c4423bSMarcelo Tosatti def_bool n 840a1c4423bSMarcelo Tosatti prompt "Disable host haltpoll when loading haltpoll driver" 841a1c4423bSMarcelo Tosatti help 842a1c4423bSMarcelo Tosatti If virtualized under KVM, disable host haltpoll. 843a1c4423bSMarcelo Tosatti 8447733607fSMaran Wilsonconfig PVH 8457733607fSMaran Wilson bool "Support for running PVH guests" 846a7f7f624SMasahiro Yamada help 8477733607fSMaran Wilson This option enables the PVH entry point for guest virtual machines 8487733607fSMaran Wilson as specified in the x86/HVM direct boot ABI. 8497733607fSMaran Wilson 8506276a074SBorislav Petkovconfig PARAVIRT_TIME_ACCOUNTING 8516276a074SBorislav Petkov bool "Paravirtual steal time accounting" 8526276a074SBorislav Petkov depends on PARAVIRT 853a7f7f624SMasahiro Yamada help 8546276a074SBorislav Petkov Select this option to enable fine granularity task steal time 8556276a074SBorislav Petkov accounting. Time spent executing other tasks in parallel with 8566276a074SBorislav Petkov the current vCPU is discounted from the vCPU power. To account for 8576276a074SBorislav Petkov that, there can be a small performance impact. 8586276a074SBorislav Petkov 8596276a074SBorislav Petkov If in doubt, say N here. 8606276a074SBorislav Petkov 8617af192c9SGerd Hoffmannconfig PARAVIRT_CLOCK 8627af192c9SGerd Hoffmann bool 8637af192c9SGerd Hoffmann 8644a362601SJan Kiszkaconfig JAILHOUSE_GUEST 8654a362601SJan Kiszka bool "Jailhouse non-root cell support" 866abde587bSArnd Bergmann depends on X86_64 && PCI 86787e65d05SJan Kiszka select X86_PM_TIMER 868a7f7f624SMasahiro Yamada help 8694a362601SJan Kiszka This option allows to run Linux as guest in a Jailhouse non-root 8704a362601SJan Kiszka cell. You can leave this option disabled if you only want to start 8714a362601SJan Kiszka Jailhouse and run Linux afterwards in the root cell. 8724a362601SJan Kiszka 873ec7972c9SZhao Yakuiconfig ACRN_GUEST 874ec7972c9SZhao Yakui bool "ACRN Guest support" 875ec7972c9SZhao Yakui depends on X86_64 876498ad393SZhao Yakui select X86_HV_CALLBACK_VECTOR 877ec7972c9SZhao Yakui help 878ec7972c9SZhao Yakui This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 879ec7972c9SZhao Yakui a flexible, lightweight reference open-source hypervisor, built with 880ec7972c9SZhao Yakui real-time and safety-criticality in mind. It is built for embedded 881ec7972c9SZhao Yakui IOT with small footprint and real-time features. More details can be 882ec7972c9SZhao Yakui found in https://projectacrn.org/. 883ec7972c9SZhao Yakui 88459bd54a8SKuppuswamy Sathyanarayananconfig INTEL_TDX_GUEST 88559bd54a8SKuppuswamy Sathyanarayanan bool "Intel TDX (Trust Domain Extensions) - Guest Support" 88659bd54a8SKuppuswamy Sathyanarayanan depends on X86_64 && CPU_SUP_INTEL 88759bd54a8SKuppuswamy Sathyanarayanan depends on X86_X2APIC 88841394e33SKirill A. Shutemov select ARCH_HAS_CC_PLATFORM 889968b4931SKirill A. Shutemov select X86_MEM_ENCRYPT 89077a512e3SSean Christopherson select X86_MCE 89159bd54a8SKuppuswamy Sathyanarayanan help 89259bd54a8SKuppuswamy Sathyanarayanan Support running as a guest under Intel TDX. Without this support, 89359bd54a8SKuppuswamy Sathyanarayanan the guest kernel can not boot or run under TDX. 89459bd54a8SKuppuswamy Sathyanarayanan TDX includes memory encryption and integrity capabilities 89559bd54a8SKuppuswamy Sathyanarayanan which protect the confidentiality and integrity of guest 89659bd54a8SKuppuswamy Sathyanarayanan memory contents and CPU state. TDX guests are protected from 89759bd54a8SKuppuswamy Sathyanarayanan some attacks from the VMM. 89859bd54a8SKuppuswamy Sathyanarayanan 8996276a074SBorislav Petkovendif # HYPERVISOR_GUEST 90097349135SJeremy Fitzhardinge 901506f1d07SSam Ravnborgsource "arch/x86/Kconfig.cpu" 902506f1d07SSam Ravnborg 903506f1d07SSam Ravnborgconfig HPET_TIMER 9043c2362e6SHarvey Harrison def_bool X86_64 905506f1d07SSam Ravnborg prompt "HPET Timer Support" if X86_32 906a7f7f624SMasahiro Yamada help 907506f1d07SSam Ravnborg Use the IA-PC HPET (High Precision Event Timer) to manage 908506f1d07SSam Ravnborg time in preference to the PIT and RTC, if a HPET is 909506f1d07SSam Ravnborg present. 910506f1d07SSam Ravnborg HPET is the next generation timer replacing legacy 8254s. 911506f1d07SSam Ravnborg The HPET provides a stable time base on SMP 912506f1d07SSam Ravnborg systems, unlike the TSC, but it is more expensive to access, 9134e7f9df2SMichael S. Tsirkin as it is off-chip. The interface used is documented 9144e7f9df2SMichael S. Tsirkin in the HPET spec, revision 1. 915506f1d07SSam Ravnborg 916506f1d07SSam Ravnborg You can safely choose Y here. However, HPET will only be 917506f1d07SSam Ravnborg activated if the platform and the BIOS support this feature. 918506f1d07SSam Ravnborg Otherwise the 8254 will be used for timing services. 919506f1d07SSam Ravnborg 920506f1d07SSam Ravnborg Choose N to continue using the legacy 8254 timer. 921506f1d07SSam Ravnborg 922506f1d07SSam Ravnborgconfig HPET_EMULATE_RTC 9233c2362e6SHarvey Harrison def_bool y 9243228e1dcSAnand K Mistry depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 925506f1d07SSam Ravnborg 9266a108a14SDavid Rientjes# Mark as expert because too many people got it wrong. 927506f1d07SSam Ravnborg# The code disables itself when not needed. 9287ae9392cSThomas Petazzoniconfig DMI 9297ae9392cSThomas Petazzoni default y 930cf074402SArd Biesheuvel select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 9316a108a14SDavid Rientjes bool "Enable DMI scanning" if EXPERT 932a7f7f624SMasahiro Yamada help 9337ae9392cSThomas Petazzoni Enabled scanning of DMI to identify machine quirks. Say Y 9347ae9392cSThomas Petazzoni here unless you have verified that your setup is not 9357ae9392cSThomas Petazzoni affected by entries in the DMI blacklist. Required by PNP 9367ae9392cSThomas Petazzoni BIOS code. 9377ae9392cSThomas Petazzoni 938506f1d07SSam Ravnborgconfig GART_IOMMU 93938901f1cSAndi Kleen bool "Old AMD GART IOMMU support" 9402f9237d4SChristoph Hellwig select DMA_OPS 941a4ce5a48SChristoph Hellwig select IOMMU_HELPER 942506f1d07SSam Ravnborg select SWIOTLB 94323ac4ae8SAndreas Herrmann depends on X86_64 && PCI && AMD_NB 944a7f7f624SMasahiro Yamada help 945ced3c42cSIngo Molnar Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 946ced3c42cSIngo Molnar GART based hardware IOMMUs. 947ced3c42cSIngo Molnar 948ced3c42cSIngo Molnar The GART supports full DMA access for devices with 32-bit access 949ced3c42cSIngo Molnar limitations, on systems with more than 3 GB. This is usually needed 950ced3c42cSIngo Molnar for USB, sound, many IDE/SATA chipsets and some other devices. 951ced3c42cSIngo Molnar 952ced3c42cSIngo Molnar Newer systems typically have a modern AMD IOMMU, supported via 953ced3c42cSIngo Molnar the CONFIG_AMD_IOMMU=y config option. 954ced3c42cSIngo Molnar 955ced3c42cSIngo Molnar In normal configurations this driver is only active when needed: 956ced3c42cSIngo Molnar there's more than 3 GB of memory and the system contains a 957ced3c42cSIngo Molnar 32-bit limited device. 958ced3c42cSIngo Molnar 959ced3c42cSIngo Molnar If unsure, say Y. 960506f1d07SSam Ravnborg 9618b766b0fSMichal Suchanekconfig BOOT_VESA_SUPPORT 9628b766b0fSMichal Suchanek bool 9638b766b0fSMichal Suchanek help 9648b766b0fSMichal Suchanek If true, at least one selected framebuffer driver can take advantage 9658b766b0fSMichal Suchanek of VESA video modes set at an early boot stage via the vga= parameter. 9668b766b0fSMichal Suchanek 9671184dc2fSMike Travisconfig MAXSMP 968ddb0c5a6SSamuel Thibault bool "Enable Maximum number of SMP Processors and NUMA Nodes" 9696ea30386SKees Cook depends on X86_64 && SMP && DEBUG_KERNEL 97036f5101aSMike Travis select CPUMASK_OFFSTACK 971a7f7f624SMasahiro Yamada help 972ddb0c5a6SSamuel Thibault Enable maximum number of CPUS and NUMA Nodes for this architecture. 9731184dc2fSMike Travis If unsure, say N. 974506f1d07SSam Ravnborg 975aec6487eSIngo Molnar# 976aec6487eSIngo Molnar# The maximum number of CPUs supported: 977aec6487eSIngo Molnar# 978aec6487eSIngo Molnar# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 979aec6487eSIngo Molnar# and which can be configured interactively in the 980aec6487eSIngo Molnar# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 981aec6487eSIngo Molnar# 982aec6487eSIngo Molnar# The ranges are different on 32-bit and 64-bit kernels, depending on 983aec6487eSIngo Molnar# hardware capabilities and scalability features of the kernel. 984aec6487eSIngo Molnar# 985aec6487eSIngo Molnar# ( If MAXSMP is enabled we just use the highest possible value and disable 986aec6487eSIngo Molnar# interactive configuration. ) 987aec6487eSIngo Molnar# 988a0d0bb4dSRandy Dunlap 989aec6487eSIngo Molnarconfig NR_CPUS_RANGE_BEGIN 990a0d0bb4dSRandy Dunlap int 991aec6487eSIngo Molnar default NR_CPUS_RANGE_END if MAXSMP 992a0d0bb4dSRandy Dunlap default 1 if !SMP 993a0d0bb4dSRandy Dunlap default 2 994a0d0bb4dSRandy Dunlap 995aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 996a0d0bb4dSRandy Dunlap int 997a0d0bb4dSRandy Dunlap depends on X86_32 998aec6487eSIngo Molnar default 64 if SMP && X86_BIGSMP 999aec6487eSIngo Molnar default 8 if SMP && !X86_BIGSMP 1000a0d0bb4dSRandy Dunlap default 1 if !SMP 1001a0d0bb4dSRandy Dunlap 1002aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 1003a0d0bb4dSRandy Dunlap int 1004a0d0bb4dSRandy Dunlap depends on X86_64 10051edae1aeSScott Wood default 8192 if SMP && CPUMASK_OFFSTACK 10061edae1aeSScott Wood default 512 if SMP && !CPUMASK_OFFSTACK 1007a0d0bb4dSRandy Dunlap default 1 if !SMP 1008aec6487eSIngo Molnar 1009aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 1010aec6487eSIngo Molnar int 1011aec6487eSIngo Molnar depends on X86_32 1012aec6487eSIngo Molnar default 32 if X86_BIGSMP 1013aec6487eSIngo Molnar default 8 if SMP 1014aec6487eSIngo Molnar default 1 if !SMP 1015aec6487eSIngo Molnar 1016aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 1017aec6487eSIngo Molnar int 1018aec6487eSIngo Molnar depends on X86_64 1019a0d0bb4dSRandy Dunlap default 8192 if MAXSMP 1020a0d0bb4dSRandy Dunlap default 64 if SMP 1021aec6487eSIngo Molnar default 1 if !SMP 1022a0d0bb4dSRandy Dunlap 1023506f1d07SSam Ravnborgconfig NR_CPUS 102436f5101aSMike Travis int "Maximum number of CPUs" if SMP && !MAXSMP 1025aec6487eSIngo Molnar range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1026aec6487eSIngo Molnar default NR_CPUS_DEFAULT 1027a7f7f624SMasahiro Yamada help 1028506f1d07SSam Ravnborg This allows you to specify the maximum number of CPUs which this 1029bb61ccc7SJosh Boyer kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1030cad14bb9SKirill A. Shutemov supported value is 8192, otherwise the maximum value is 512. The 1031506f1d07SSam Ravnborg minimum value which makes sense is 2. 1032506f1d07SSam Ravnborg 1033aec6487eSIngo Molnar This is purely to save memory: each supported CPU adds about 8KB 1034aec6487eSIngo Molnar to the kernel image. 1035506f1d07SSam Ravnborg 103666558b73STim Chenconfig SCHED_CLUSTER 103766558b73STim Chen bool "Cluster scheduler support" 103866558b73STim Chen depends on SMP 103966558b73STim Chen default y 104066558b73STim Chen help 104166558b73STim Chen Cluster scheduler support improves the CPU scheduler's decision 104266558b73STim Chen making when dealing with machines that have clusters of CPUs. 104366558b73STim Chen Cluster usually means a couple of CPUs which are placed closely 104466558b73STim Chen by sharing mid-level caches, last-level cache tags or internal 104566558b73STim Chen busses. 104666558b73STim Chen 1047506f1d07SSam Ravnborgconfig SCHED_SMT 1048dbe73364SThomas Gleixner def_bool y if SMP 1049506f1d07SSam Ravnborg 1050506f1d07SSam Ravnborgconfig SCHED_MC 10513c2362e6SHarvey Harrison def_bool y 10523c2362e6SHarvey Harrison prompt "Multi-core scheduler support" 1053c8e56d20SBorislav Petkov depends on SMP 1054a7f7f624SMasahiro Yamada help 1055506f1d07SSam Ravnborg Multi-core scheduler support improves the CPU scheduler's decision 1056506f1d07SSam Ravnborg making when dealing with multi-core CPU chips at a cost of slightly 1057506f1d07SSam Ravnborg increased overhead in some places. If unsure say N here. 1058506f1d07SSam Ravnborg 1059de966cf4STim Chenconfig SCHED_MC_PRIO 1060de966cf4STim Chen bool "CPU core priorities scheduler support" 10610a21fc12SIngo Molnar depends on SCHED_MC && CPU_SUP_INTEL 10620a21fc12SIngo Molnar select X86_INTEL_PSTATE 10630a21fc12SIngo Molnar select CPU_FREQ 1064de966cf4STim Chen default y 1065a7f7f624SMasahiro Yamada help 1066de966cf4STim Chen Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1067de966cf4STim Chen core ordering determined at manufacturing time, which allows 1068de966cf4STim Chen certain cores to reach higher turbo frequencies (when running 1069de966cf4STim Chen single threaded workloads) than others. 1070de966cf4STim Chen 1071de966cf4STim Chen Enabling this kernel feature teaches the scheduler about 1072de966cf4STim Chen the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1073de966cf4STim Chen scheduler's CPU selection logic accordingly, so that higher 1074de966cf4STim Chen overall system performance can be achieved. 1075de966cf4STim Chen 1076de966cf4STim Chen This feature will have no effect on CPUs without this feature. 1077de966cf4STim Chen 1078de966cf4STim Chen If unsure say Y here. 10795e76b2abSTim Chen 108030b8b006SThomas Gleixnerconfig UP_LATE_INIT 108130b8b006SThomas Gleixner def_bool y 1082ba360f88SThomas Gleixner depends on !SMP && X86_LOCAL_APIC 108330b8b006SThomas Gleixner 1084506f1d07SSam Ravnborgconfig X86_UP_APIC 108550849eefSJan Beulich bool "Local APIC support on uniprocessors" if !PCI_MSI 108650849eefSJan Beulich default PCI_MSI 108738a1dfdaSBryan O'Donoghue depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1088a7f7f624SMasahiro Yamada help 1089506f1d07SSam Ravnborg A local APIC (Advanced Programmable Interrupt Controller) is an 1090506f1d07SSam Ravnborg integrated interrupt controller in the CPU. If you have a single-CPU 1091506f1d07SSam Ravnborg system which has a processor with a local APIC, you can say Y here to 1092506f1d07SSam Ravnborg enable and use it. If you say Y here even though your machine doesn't 1093506f1d07SSam Ravnborg have a local APIC, then the kernel will still run with no slowdown at 1094506f1d07SSam Ravnborg all. The local APIC supports CPU-generated self-interrupts (timer, 1095506f1d07SSam Ravnborg performance counters), and the NMI watchdog which detects hard 1096506f1d07SSam Ravnborg lockups. 1097506f1d07SSam Ravnborg 1098506f1d07SSam Ravnborgconfig X86_UP_IOAPIC 1099506f1d07SSam Ravnborg bool "IO-APIC support on uniprocessors" 1100506f1d07SSam Ravnborg depends on X86_UP_APIC 1101a7f7f624SMasahiro Yamada help 1102506f1d07SSam Ravnborg An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1103506f1d07SSam Ravnborg SMP-capable replacement for PC-style interrupt controllers. Most 1104506f1d07SSam Ravnborg SMP systems and many recent uniprocessor systems have one. 1105506f1d07SSam Ravnborg 1106506f1d07SSam Ravnborg If you have a single-CPU system with an IO-APIC, you can say Y here 1107506f1d07SSam Ravnborg to use it. If you say Y here even though your machine doesn't have 1108506f1d07SSam Ravnborg an IO-APIC, then the kernel will still run with no slowdown at all. 1109506f1d07SSam Ravnborg 1110506f1d07SSam Ravnborgconfig X86_LOCAL_APIC 11113c2362e6SHarvey Harrison def_bool y 11120dbc6078SThomas Petazzoni depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1113b5dc8e6cSJiang Liu select IRQ_DOMAIN_HIERARCHY 1114506f1d07SSam Ravnborg 1115506f1d07SSam Ravnborgconfig X86_IO_APIC 1116b1da1e71SJan Beulich def_bool y 1117b1da1e71SJan Beulich depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1118506f1d07SSam Ravnborg 111941b9eb26SStefan Assmannconfig X86_REROUTE_FOR_BROKEN_BOOT_IRQS 112041b9eb26SStefan Assmann bool "Reroute for broken boot IRQs" 112141b9eb26SStefan Assmann depends on X86_IO_APIC 1122a7f7f624SMasahiro Yamada help 112341b9eb26SStefan Assmann This option enables a workaround that fixes a source of 112441b9eb26SStefan Assmann spurious interrupts. This is recommended when threaded 112541b9eb26SStefan Assmann interrupt handling is used on systems where the generation of 112641b9eb26SStefan Assmann superfluous "boot interrupts" cannot be disabled. 112741b9eb26SStefan Assmann 112841b9eb26SStefan Assmann Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 112941b9eb26SStefan Assmann entry in the chipset's IO-APIC is masked (as, e.g. the RT 113041b9eb26SStefan Assmann kernel does during interrupt handling). On chipsets where this 113141b9eb26SStefan Assmann boot IRQ generation cannot be disabled, this workaround keeps 113241b9eb26SStefan Assmann the original IRQ line masked so that only the equivalent "boot 113341b9eb26SStefan Assmann IRQ" is delivered to the CPUs. The workaround also tells the 113441b9eb26SStefan Assmann kernel to set up the IRQ handler on the boot IRQ line. In this 113541b9eb26SStefan Assmann way only one interrupt is delivered to the kernel. Otherwise 113641b9eb26SStefan Assmann the spurious second interrupt may cause the kernel to bring 113741b9eb26SStefan Assmann down (vital) interrupt lines. 113841b9eb26SStefan Assmann 113941b9eb26SStefan Assmann Only affects "broken" chipsets. Interrupt sharing may be 114041b9eb26SStefan Assmann increased on these systems. 114141b9eb26SStefan Assmann 1142506f1d07SSam Ravnborgconfig X86_MCE 1143bab9bc65SAndi Kleen bool "Machine Check / overheating reporting" 1144648ed940SChen, Gong select GENERIC_ALLOCATOR 1145e57dbaf7SBorislav Petkov default y 1146a7f7f624SMasahiro Yamada help 1147bab9bc65SAndi Kleen Machine Check support allows the processor to notify the 1148bab9bc65SAndi Kleen kernel if it detects a problem (e.g. overheating, data corruption). 1149506f1d07SSam Ravnborg The action the kernel takes depends on the severity of the problem, 1150bab9bc65SAndi Kleen ranging from warning messages to halting the machine. 11514efc0670SAndi Kleen 11525de97c9fSTony Luckconfig X86_MCELOG_LEGACY 11535de97c9fSTony Luck bool "Support for deprecated /dev/mcelog character device" 11545de97c9fSTony Luck depends on X86_MCE 1155a7f7f624SMasahiro Yamada help 11565de97c9fSTony Luck Enable support for /dev/mcelog which is needed by the old mcelog 11575de97c9fSTony Luck userspace logging daemon. Consider switching to the new generation 11585de97c9fSTony Luck rasdaemon solution. 11595de97c9fSTony Luck 1160506f1d07SSam Ravnborgconfig X86_MCE_INTEL 11613c2362e6SHarvey Harrison def_bool y 11623c2362e6SHarvey Harrison prompt "Intel MCE features" 1163c1ebf835SAndi Kleen depends on X86_MCE && X86_LOCAL_APIC 1164a7f7f624SMasahiro Yamada help 1165506f1d07SSam Ravnborg Additional support for intel specific MCE features such as 1166506f1d07SSam Ravnborg the thermal monitor. 1167506f1d07SSam Ravnborg 1168506f1d07SSam Ravnborgconfig X86_MCE_AMD 11693c2362e6SHarvey Harrison def_bool y 11703c2362e6SHarvey Harrison prompt "AMD MCE features" 1171f5382de9SYazen Ghannam depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1172a7f7f624SMasahiro Yamada help 1173506f1d07SSam Ravnborg Additional support for AMD specific MCE features such as 1174506f1d07SSam Ravnborg the DRAM Error Threshold. 1175506f1d07SSam Ravnborg 11764efc0670SAndi Kleenconfig X86_ANCIENT_MCE 11776fc108a0SJan Beulich bool "Support for old Pentium 5 / WinChip machine checks" 1178c31d9633SAndi Kleen depends on X86_32 && X86_MCE 1179a7f7f624SMasahiro Yamada help 11804efc0670SAndi Kleen Include support for machine check handling on old Pentium 5 or WinChip 11815065a706SMasanari Iida systems. These typically need to be enabled explicitly on the command 11824efc0670SAndi Kleen line. 11834efc0670SAndi Kleen 1184b2762686SAndi Kleenconfig X86_MCE_THRESHOLD 1185b2762686SAndi Kleen depends on X86_MCE_AMD || X86_MCE_INTEL 11866fc108a0SJan Beulich def_bool y 1187b2762686SAndi Kleen 1188ea149b36SAndi Kleenconfig X86_MCE_INJECT 1189bc8e80d5SBorislav Petkov depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1190ea149b36SAndi Kleen tristate "Machine check injector support" 1191a7f7f624SMasahiro Yamada help 1192ea149b36SAndi Kleen Provide support for injecting machine checks for testing purposes. 1193ea149b36SAndi Kleen If you don't know what a machine check is and you don't do kernel 1194ea149b36SAndi Kleen QA it is safe to say n. 1195ea149b36SAndi Kleen 119607dc900eSPeter Zijlstrasource "arch/x86/events/Kconfig" 1197e633c65aSKan Liang 11985aef51c3SAndy Lutomirskiconfig X86_LEGACY_VM86 11991e642812SIngo Molnar bool "Legacy VM86 support" 1200506f1d07SSam Ravnborg depends on X86_32 1201a7f7f624SMasahiro Yamada help 12025aef51c3SAndy Lutomirski This option allows user programs to put the CPU into V8086 12035aef51c3SAndy Lutomirski mode, which is an 80286-era approximation of 16-bit real mode. 12045aef51c3SAndy Lutomirski 12055aef51c3SAndy Lutomirski Some very old versions of X and/or vbetool require this option 12065aef51c3SAndy Lutomirski for user mode setting. Similarly, DOSEMU will use it if 12075aef51c3SAndy Lutomirski available to accelerate real mode DOS programs. However, any 12085aef51c3SAndy Lutomirski recent version of DOSEMU, X, or vbetool should be fully 12095aef51c3SAndy Lutomirski functional even without kernel VM86 support, as they will all 12101e642812SIngo Molnar fall back to software emulation. Nevertheless, if you are using 12111e642812SIngo Molnar a 16-bit DOS program where 16-bit performance matters, vm86 12121e642812SIngo Molnar mode might be faster than emulation and you might want to 12131e642812SIngo Molnar enable this option. 12145aef51c3SAndy Lutomirski 12151e642812SIngo Molnar Note that any app that works on a 64-bit kernel is unlikely to 12161e642812SIngo Molnar need this option, as 64-bit kernels don't, and can't, support 12171e642812SIngo Molnar V8086 mode. This option is also unrelated to 16-bit protected 12181e642812SIngo Molnar mode and is not needed to run most 16-bit programs under Wine. 12195aef51c3SAndy Lutomirski 12201e642812SIngo Molnar Enabling this option increases the complexity of the kernel 12211e642812SIngo Molnar and slows down exception handling a tiny bit. 12225aef51c3SAndy Lutomirski 12231e642812SIngo Molnar If unsure, say N here. 12245aef51c3SAndy Lutomirski 12255aef51c3SAndy Lutomirskiconfig VM86 12265aef51c3SAndy Lutomirski bool 12275aef51c3SAndy Lutomirski default X86_LEGACY_VM86 122834273f41SH. Peter Anvin 122934273f41SH. Peter Anvinconfig X86_16BIT 123034273f41SH. Peter Anvin bool "Enable support for 16-bit segments" if EXPERT 123134273f41SH. Peter Anvin default y 1232a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 1233a7f7f624SMasahiro Yamada help 123434273f41SH. Peter Anvin This option is required by programs like Wine to run 16-bit 123534273f41SH. Peter Anvin protected mode legacy code on x86 processors. Disabling 123634273f41SH. Peter Anvin this option saves about 300 bytes on i386, or around 6K text 123734273f41SH. Peter Anvin plus 16K runtime memory on x86-64, 123834273f41SH. Peter Anvin 123934273f41SH. Peter Anvinconfig X86_ESPFIX32 124034273f41SH. Peter Anvin def_bool y 124134273f41SH. Peter Anvin depends on X86_16BIT && X86_32 1242506f1d07SSam Ravnborg 1243197725deSH. Peter Anvinconfig X86_ESPFIX64 1244197725deSH. Peter Anvin def_bool y 124534273f41SH. Peter Anvin depends on X86_16BIT && X86_64 1246506f1d07SSam Ravnborg 12471ad83c85SAndy Lutomirskiconfig X86_VSYSCALL_EMULATION 12481ad83c85SAndy Lutomirski bool "Enable vsyscall emulation" if EXPERT 12491ad83c85SAndy Lutomirski default y 12501ad83c85SAndy Lutomirski depends on X86_64 1251a7f7f624SMasahiro Yamada help 12521ad83c85SAndy Lutomirski This enables emulation of the legacy vsyscall page. Disabling 12531ad83c85SAndy Lutomirski it is roughly equivalent to booting with vsyscall=none, except 12541ad83c85SAndy Lutomirski that it will also disable the helpful warning if a program 12551ad83c85SAndy Lutomirski tries to use a vsyscall. With this option set to N, offending 12561ad83c85SAndy Lutomirski programs will just segfault, citing addresses of the form 12571ad83c85SAndy Lutomirski 0xffffffffff600?00. 12581ad83c85SAndy Lutomirski 12591ad83c85SAndy Lutomirski This option is required by many programs built before 2013, and 12601ad83c85SAndy Lutomirski care should be used even with newer programs if set to N. 12611ad83c85SAndy Lutomirski 12621ad83c85SAndy Lutomirski Disabling this option saves about 7K of kernel size and 12631ad83c85SAndy Lutomirski possibly 4K of additional runtime pagetable memory. 12641ad83c85SAndy Lutomirski 1265111e7b15SThomas Gleixnerconfig X86_IOPL_IOPERM 1266111e7b15SThomas Gleixner bool "IOPERM and IOPL Emulation" 1267a24ca997SThomas Gleixner default y 1268a7f7f624SMasahiro Yamada help 1269111e7b15SThomas Gleixner This enables the ioperm() and iopl() syscalls which are necessary 1270111e7b15SThomas Gleixner for legacy applications. 1271111e7b15SThomas Gleixner 1272c8137aceSThomas Gleixner Legacy IOPL support is an overbroad mechanism which allows user 1273c8137aceSThomas Gleixner space aside of accessing all 65536 I/O ports also to disable 1274c8137aceSThomas Gleixner interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1275c8137aceSThomas Gleixner capabilities and permission from potentially active security 1276c8137aceSThomas Gleixner modules. 1277c8137aceSThomas Gleixner 1278c8137aceSThomas Gleixner The emulation restricts the functionality of the syscall to 1279c8137aceSThomas Gleixner only allowing the full range I/O port access, but prevents the 1280a24ca997SThomas Gleixner ability to disable interrupts from user space which would be 1281a24ca997SThomas Gleixner granted if the hardware IOPL mechanism would be used. 1282c8137aceSThomas Gleixner 1283506f1d07SSam Ravnborgconfig TOSHIBA 1284506f1d07SSam Ravnborg tristate "Toshiba Laptop support" 1285506f1d07SSam Ravnborg depends on X86_32 1286a7f7f624SMasahiro Yamada help 1287506f1d07SSam Ravnborg This adds a driver to safely access the System Management Mode of 1288506f1d07SSam Ravnborg the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1289506f1d07SSam Ravnborg not work on models with a Phoenix BIOS. The System Management Mode 1290506f1d07SSam Ravnborg is used to set the BIOS and power saving options on Toshiba portables. 1291506f1d07SSam Ravnborg 1292506f1d07SSam Ravnborg For information on utilities to make use of this driver see the 1293506f1d07SSam Ravnborg Toshiba Linux utilities web site at: 1294506f1d07SSam Ravnborg <http://www.buzzard.org.uk/toshiba/>. 1295506f1d07SSam Ravnborg 1296506f1d07SSam Ravnborg Say Y if you intend to run this kernel on a Toshiba portable. 1297506f1d07SSam Ravnborg Say N otherwise. 1298506f1d07SSam Ravnborg 1299506f1d07SSam Ravnborgconfig X86_REBOOTFIXUPS 13009ba16087SJan Beulich bool "Enable X86 board specific fixups for reboot" 13019ba16087SJan Beulich depends on X86_32 1302a7f7f624SMasahiro Yamada help 1303506f1d07SSam Ravnborg This enables chipset and/or board specific fixups to be done 1304506f1d07SSam Ravnborg in order to get reboot to work correctly. This is only needed on 1305506f1d07SSam Ravnborg some combinations of hardware and BIOS. The symptom, for which 1306506f1d07SSam Ravnborg this config is intended, is when reboot ends with a stalled/hung 1307506f1d07SSam Ravnborg system. 1308506f1d07SSam Ravnborg 1309506f1d07SSam Ravnborg Currently, the only fixup is for the Geode machines using 13105e3a77e9SFlorian Fainelli CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1311506f1d07SSam Ravnborg 1312506f1d07SSam Ravnborg Say Y if you want to enable the fixup. Currently, it's safe to 1313506f1d07SSam Ravnborg enable this option even if you don't need it. 1314506f1d07SSam Ravnborg Say N otherwise. 1315506f1d07SSam Ravnborg 1316506f1d07SSam Ravnborgconfig MICROCODE 13179a2bc335SBorislav Petkov bool "CPU microcode loading support" 13189a2bc335SBorislav Petkov default y 131980030e3dSBorislav Petkov depends on CPU_SUP_AMD || CPU_SUP_INTEL 1320a7f7f624SMasahiro Yamada help 1321506f1d07SSam Ravnborg If you say Y here, you will be able to update the microcode on 13225f9c01aaSBorislav Petkov Intel and AMD processors. The Intel support is for the IA32 family, 13235f9c01aaSBorislav Petkov e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 13245f9c01aaSBorislav Petkov AMD support is for families 0x10 and later. You will obviously need 13255f9c01aaSBorislav Petkov the actual microcode binary data itself which is not shipped with 13265f9c01aaSBorislav Petkov the Linux kernel. 1327506f1d07SSam Ravnborg 13285f9c01aaSBorislav Petkov The preferred method to load microcode from a detached initrd is described 1329ff61f079SJonathan Corbet in Documentation/arch/x86/microcode.rst. For that you need to enable 13305f9c01aaSBorislav Petkov CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 13315f9c01aaSBorislav Petkov initrd for microcode blobs. 1332506f1d07SSam Ravnborg 1333c508c46eSBenjamin Gilbert In addition, you can build the microcode into the kernel. For that you 1334c508c46eSBenjamin Gilbert need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1335c508c46eSBenjamin Gilbert config option. 1336506f1d07SSam Ravnborg 13378d86f390SPeter Orubaconfig MICROCODE_INTEL 1338e43f6e67SBorislav Petkov bool "Intel microcode loading support" 13399c55d99eSBorislav Petkov depends on CPU_SUP_INTEL && MICROCODE 13408d86f390SPeter Oruba default MICROCODE 1341a7f7f624SMasahiro Yamada help 13428d86f390SPeter Oruba This options enables microcode patch loading support for Intel 13438d86f390SPeter Oruba processors. 13448d86f390SPeter Oruba 1345b8989db9SAlan For the current Intel microcode data package go to 1346b8989db9SAlan <https://downloadcenter.intel.com> and search for 1347b8989db9SAlan 'Linux Processor Microcode Data File'. 13488d86f390SPeter Oruba 134980cc9f10SPeter Orubaconfig MICROCODE_AMD 1350e43f6e67SBorislav Petkov bool "AMD microcode loading support" 13519c55d99eSBorislav Petkov depends on CPU_SUP_AMD && MICROCODE 1352a7f7f624SMasahiro Yamada help 135380cc9f10SPeter Oruba If you select this option, microcode patch loading support for AMD 135480cc9f10SPeter Oruba processors will be enabled. 135580cc9f10SPeter Oruba 1356a77a94f8SBorislav Petkovconfig MICROCODE_LATE_LOADING 1357a77a94f8SBorislav Petkov bool "Late microcode loading (DANGEROUS)" 1358c02f48e0SBorislav Petkov default n 1359506f1d07SSam Ravnborg depends on MICROCODE 1360a7f7f624SMasahiro Yamada help 1361a77a94f8SBorislav Petkov Loading microcode late, when the system is up and executing instructions 1362a77a94f8SBorislav Petkov is a tricky business and should be avoided if possible. Just the sequence 1363a77a94f8SBorislav Petkov of synchronizing all cores and SMT threads is one fragile dance which does 1364a77a94f8SBorislav Petkov not guarantee that cores might not softlock after the loading. Therefore, 1365a77a94f8SBorislav Petkov use this at your own risk. Late loading taints the kernel too. 1366506f1d07SSam Ravnborg 1367506f1d07SSam Ravnborgconfig X86_MSR 1368506f1d07SSam Ravnborg tristate "/dev/cpu/*/msr - Model-specific register support" 1369a7f7f624SMasahiro Yamada help 1370506f1d07SSam Ravnborg This device gives privileged processes access to the x86 1371506f1d07SSam Ravnborg Model-Specific Registers (MSRs). It is a character device with 1372506f1d07SSam Ravnborg major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1373506f1d07SSam Ravnborg MSR accesses are directed to a specific CPU on multi-processor 1374506f1d07SSam Ravnborg systems. 1375506f1d07SSam Ravnborg 1376506f1d07SSam Ravnborgconfig X86_CPUID 1377506f1d07SSam Ravnborg tristate "/dev/cpu/*/cpuid - CPU information support" 1378a7f7f624SMasahiro Yamada help 1379506f1d07SSam Ravnborg This device gives processes access to the x86 CPUID instruction to 1380506f1d07SSam Ravnborg be executed on a specific processor. It is a character device 1381506f1d07SSam Ravnborg with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1382506f1d07SSam Ravnborg /dev/cpu/31/cpuid. 1383506f1d07SSam Ravnborg 1384506f1d07SSam Ravnborgchoice 1385506f1d07SSam Ravnborg prompt "High Memory Support" 13866fc108a0SJan Beulich default HIGHMEM4G 1387506f1d07SSam Ravnborg depends on X86_32 1388506f1d07SSam Ravnborg 1389506f1d07SSam Ravnborgconfig NOHIGHMEM 1390506f1d07SSam Ravnborg bool "off" 1391a7f7f624SMasahiro Yamada help 1392506f1d07SSam Ravnborg Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1393506f1d07SSam Ravnborg However, the address space of 32-bit x86 processors is only 4 1394506f1d07SSam Ravnborg Gigabytes large. That means that, if you have a large amount of 1395506f1d07SSam Ravnborg physical memory, not all of it can be "permanently mapped" by the 1396506f1d07SSam Ravnborg kernel. The physical memory that's not permanently mapped is called 1397506f1d07SSam Ravnborg "high memory". 1398506f1d07SSam Ravnborg 1399506f1d07SSam Ravnborg If you are compiling a kernel which will never run on a machine with 1400506f1d07SSam Ravnborg more than 1 Gigabyte total physical RAM, answer "off" here (default 1401506f1d07SSam Ravnborg choice and suitable for most users). This will result in a "3GB/1GB" 1402506f1d07SSam Ravnborg split: 3GB are mapped so that each process sees a 3GB virtual memory 1403506f1d07SSam Ravnborg space and the remaining part of the 4GB virtual memory space is used 1404506f1d07SSam Ravnborg by the kernel to permanently map as much physical memory as 1405506f1d07SSam Ravnborg possible. 1406506f1d07SSam Ravnborg 1407506f1d07SSam Ravnborg If the machine has between 1 and 4 Gigabytes physical RAM, then 1408506f1d07SSam Ravnborg answer "4GB" here. 1409506f1d07SSam Ravnborg 1410506f1d07SSam Ravnborg If more than 4 Gigabytes is used then answer "64GB" here. This 1411506f1d07SSam Ravnborg selection turns Intel PAE (Physical Address Extension) mode on. 1412506f1d07SSam Ravnborg PAE implements 3-level paging on IA32 processors. PAE is fully 1413506f1d07SSam Ravnborg supported by Linux, PAE mode is implemented on all recent Intel 1414506f1d07SSam Ravnborg processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1415506f1d07SSam Ravnborg then the kernel will not boot on CPUs that don't support PAE! 1416506f1d07SSam Ravnborg 1417506f1d07SSam Ravnborg The actual amount of total physical memory will either be 1418506f1d07SSam Ravnborg auto detected or can be forced by using a kernel command line option 1419506f1d07SSam Ravnborg such as "mem=256M". (Try "man bootparam" or see the documentation of 1420506f1d07SSam Ravnborg your boot loader (lilo or loadlin) about how to pass options to the 1421506f1d07SSam Ravnborg kernel at boot time.) 1422506f1d07SSam Ravnborg 1423506f1d07SSam Ravnborg If unsure, say "off". 1424506f1d07SSam Ravnborg 1425506f1d07SSam Ravnborgconfig HIGHMEM4G 1426506f1d07SSam Ravnborg bool "4GB" 1427a7f7f624SMasahiro Yamada help 1428506f1d07SSam Ravnborg Select this if you have a 32-bit processor and between 1 and 4 1429506f1d07SSam Ravnborg gigabytes of physical RAM. 1430506f1d07SSam Ravnborg 1431506f1d07SSam Ravnborgconfig HIGHMEM64G 1432506f1d07SSam Ravnborg bool "64GB" 1433225bac2dSLukas Bulwahn depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6 1434506f1d07SSam Ravnborg select X86_PAE 1435a7f7f624SMasahiro Yamada help 1436506f1d07SSam Ravnborg Select this if you have a 32-bit processor and more than 4 1437506f1d07SSam Ravnborg gigabytes of physical RAM. 1438506f1d07SSam Ravnborg 1439506f1d07SSam Ravnborgendchoice 1440506f1d07SSam Ravnborg 1441506f1d07SSam Ravnborgchoice 14426a108a14SDavid Rientjes prompt "Memory split" if EXPERT 1443506f1d07SSam Ravnborg default VMSPLIT_3G 1444506f1d07SSam Ravnborg depends on X86_32 1445a7f7f624SMasahiro Yamada help 1446506f1d07SSam Ravnborg Select the desired split between kernel and user memory. 1447506f1d07SSam Ravnborg 1448506f1d07SSam Ravnborg If the address range available to the kernel is less than the 1449506f1d07SSam Ravnborg physical memory installed, the remaining memory will be available 1450506f1d07SSam Ravnborg as "high memory". Accessing high memory is a little more costly 1451506f1d07SSam Ravnborg than low memory, as it needs to be mapped into the kernel first. 1452506f1d07SSam Ravnborg Note that increasing the kernel address space limits the range 1453506f1d07SSam Ravnborg available to user programs, making the address space there 1454506f1d07SSam Ravnborg tighter. Selecting anything other than the default 3G/1G split 1455506f1d07SSam Ravnborg will also likely make your kernel incompatible with binary-only 1456506f1d07SSam Ravnborg kernel modules. 1457506f1d07SSam Ravnborg 1458506f1d07SSam Ravnborg If you are not absolutely sure what you are doing, leave this 1459506f1d07SSam Ravnborg option alone! 1460506f1d07SSam Ravnborg 1461506f1d07SSam Ravnborg config VMSPLIT_3G 1462506f1d07SSam Ravnborg bool "3G/1G user/kernel split" 1463506f1d07SSam Ravnborg config VMSPLIT_3G_OPT 1464506f1d07SSam Ravnborg depends on !X86_PAE 1465506f1d07SSam Ravnborg bool "3G/1G user/kernel split (for full 1G low memory)" 1466506f1d07SSam Ravnborg config VMSPLIT_2G 1467506f1d07SSam Ravnborg bool "2G/2G user/kernel split" 1468506f1d07SSam Ravnborg config VMSPLIT_2G_OPT 1469506f1d07SSam Ravnborg depends on !X86_PAE 1470506f1d07SSam Ravnborg bool "2G/2G user/kernel split (for full 2G low memory)" 1471506f1d07SSam Ravnborg config VMSPLIT_1G 1472506f1d07SSam Ravnborg bool "1G/3G user/kernel split" 1473506f1d07SSam Ravnborgendchoice 1474506f1d07SSam Ravnborg 1475506f1d07SSam Ravnborgconfig PAGE_OFFSET 1476506f1d07SSam Ravnborg hex 1477506f1d07SSam Ravnborg default 0xB0000000 if VMSPLIT_3G_OPT 1478506f1d07SSam Ravnborg default 0x80000000 if VMSPLIT_2G 1479506f1d07SSam Ravnborg default 0x78000000 if VMSPLIT_2G_OPT 1480506f1d07SSam Ravnborg default 0x40000000 if VMSPLIT_1G 1481506f1d07SSam Ravnborg default 0xC0000000 1482506f1d07SSam Ravnborg depends on X86_32 1483506f1d07SSam Ravnborg 1484506f1d07SSam Ravnborgconfig HIGHMEM 14853c2362e6SHarvey Harrison def_bool y 1486506f1d07SSam Ravnborg depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1487506f1d07SSam Ravnborg 1488506f1d07SSam Ravnborgconfig X86_PAE 14899ba16087SJan Beulich bool "PAE (Physical Address Extension) Support" 1490506f1d07SSam Ravnborg depends on X86_32 && !HIGHMEM4G 1491d4a451d5SChristoph Hellwig select PHYS_ADDR_T_64BIT 14929d99c712SChristian Melki select SWIOTLB 1493a7f7f624SMasahiro Yamada help 1494506f1d07SSam Ravnborg PAE is required for NX support, and furthermore enables 1495506f1d07SSam Ravnborg larger swapspace support for non-overcommit purposes. It 1496506f1d07SSam Ravnborg has the cost of more pagetable lookup overhead, and also 1497506f1d07SSam Ravnborg consumes more pagetable space per process. 1498506f1d07SSam Ravnborg 149977ef56e4SKirill A. Shutemovconfig X86_5LEVEL 150077ef56e4SKirill A. Shutemov bool "Enable 5-level page tables support" 150118ec1eafSKirill A. Shutemov default y 1502eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 1503162434e7SKirill A. Shutemov select SPARSEMEM_VMEMMAP 150477ef56e4SKirill A. Shutemov depends on X86_64 1505a7f7f624SMasahiro Yamada help 150677ef56e4SKirill A. Shutemov 5-level paging enables access to larger address space: 150777ef56e4SKirill A. Shutemov up to 128 PiB of virtual address space and 4 PiB of 150877ef56e4SKirill A. Shutemov physical address space. 150977ef56e4SKirill A. Shutemov 151077ef56e4SKirill A. Shutemov It will be supported by future Intel CPUs. 151177ef56e4SKirill A. Shutemov 15126657fca0SKirill A. Shutemov A kernel with the option enabled can be booted on machines that 15136657fca0SKirill A. Shutemov support 4- or 5-level paging. 151477ef56e4SKirill A. Shutemov 1515ff61f079SJonathan Corbet See Documentation/arch/x86/x86_64/5level-paging.rst for more 151677ef56e4SKirill A. Shutemov information. 151777ef56e4SKirill A. Shutemov 151877ef56e4SKirill A. Shutemov Say N if unsure. 151977ef56e4SKirill A. Shutemov 152010971ab2SIngo Molnarconfig X86_DIRECT_GBPAGES 1521e5008abeSLuis R. Rodriguez def_bool y 15222e1da13fSVlastimil Babka depends on X86_64 1523a7f7f624SMasahiro Yamada help 152410971ab2SIngo Molnar Certain kernel features effectively disable kernel 152510971ab2SIngo Molnar linear 1 GB mappings (even if the CPU otherwise 152610971ab2SIngo Molnar supports them), so don't confuse the user by printing 152710971ab2SIngo Molnar that we have them enabled. 15289e899816SNick Piggin 15295c280cf6SThomas Gleixnerconfig X86_CPA_STATISTICS 15305c280cf6SThomas Gleixner bool "Enable statistic for Change Page Attribute" 15315c280cf6SThomas Gleixner depends on DEBUG_FS 1532a7f7f624SMasahiro Yamada help 1533b75baaf3SIngo Molnar Expose statistics about the Change Page Attribute mechanism, which 1534a943245aSColin Ian King helps to determine the effectiveness of preserving large and huge 15355c280cf6SThomas Gleixner page mappings when mapping protections are changed. 15365c280cf6SThomas Gleixner 153720f07a04SKirill A. Shutemovconfig X86_MEM_ENCRYPT 153820f07a04SKirill A. Shutemov select ARCH_HAS_FORCE_DMA_UNENCRYPTED 153920f07a04SKirill A. Shutemov select DYNAMIC_PHYSICAL_MASK 154020f07a04SKirill A. Shutemov def_bool n 154120f07a04SKirill A. Shutemov 15427744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT 15437744ccdbSTom Lendacky bool "AMD Secure Memory Encryption (SME) support" 15447744ccdbSTom Lendacky depends on X86_64 && CPU_SUP_AMD 154582fef0adSDavid Rientjes select DMA_COHERENT_POOL 1546ce9084baSArd Biesheuvel select ARCH_USE_MEMREMAP_PROT 1547597cfe48SJoerg Roedel select INSTRUCTION_DECODER 1548aa5a4611STom Lendacky select ARCH_HAS_CC_PLATFORM 154920f07a04SKirill A. Shutemov select X86_MEM_ENCRYPT 1550a7f7f624SMasahiro Yamada help 15517744ccdbSTom Lendacky Say yes to enable support for the encryption of system memory. 15527744ccdbSTom Lendacky This requires an AMD processor that supports Secure Memory 15537744ccdbSTom Lendacky Encryption (SME). 15547744ccdbSTom Lendacky 15557744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 15567744ccdbSTom Lendacky bool "Activate AMD Secure Memory Encryption (SME) by default" 15577744ccdbSTom Lendacky depends on AMD_MEM_ENCRYPT 1558a7f7f624SMasahiro Yamada help 15597744ccdbSTom Lendacky Say yes to have system memory encrypted by default if running on 15607744ccdbSTom Lendacky an AMD processor that supports Secure Memory Encryption (SME). 15617744ccdbSTom Lendacky 15627744ccdbSTom Lendacky If set to Y, then the encryption of system memory can be 15637744ccdbSTom Lendacky deactivated with the mem_encrypt=off command line option. 15647744ccdbSTom Lendacky 15657744ccdbSTom Lendacky If set to N, then the encryption of system memory can be 15667744ccdbSTom Lendacky activated with the mem_encrypt=on command line option. 15677744ccdbSTom Lendacky 1568506f1d07SSam Ravnborg# Common NUMA Features 1569506f1d07SSam Ravnborgconfig NUMA 1570e133f6eaSRandy Dunlap bool "NUMA Memory Allocation and Scheduler Support" 1571506f1d07SSam Ravnborg depends on SMP 1572b5660ba7SH. Peter Anvin depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1573b5660ba7SH. Peter Anvin default y if X86_BIGSMP 15747ecd19cfSKefeng Wang select USE_PERCPU_NUMA_NODE_ID 1575a7f7f624SMasahiro Yamada help 1576e133f6eaSRandy Dunlap Enable NUMA (Non-Uniform Memory Access) support. 1577fd51b2d7SKOSAKI Motohiro 1578506f1d07SSam Ravnborg The kernel will try to allocate memory used by a CPU on the 1579506f1d07SSam Ravnborg local memory controller of the CPU and add some more 1580506f1d07SSam Ravnborg NUMA awareness to the kernel. 1581506f1d07SSam Ravnborg 1582c280ea5eSIngo Molnar For 64-bit this is recommended if the system is Intel Core i7 1583fd51b2d7SKOSAKI Motohiro (or later), AMD Opteron, or EM64T NUMA. 1584fd51b2d7SKOSAKI Motohiro 1585b5660ba7SH. Peter Anvin For 32-bit this is only needed if you boot a 32-bit 15867cf6c945SDavid Rientjes kernel on a 64-bit NUMA platform. 1587fd51b2d7SKOSAKI Motohiro 1588fd51b2d7SKOSAKI Motohiro Otherwise, you should say N. 1589506f1d07SSam Ravnborg 1590eec1d4faSHans Rosenfeldconfig AMD_NUMA 15913c2362e6SHarvey Harrison def_bool y 15923c2362e6SHarvey Harrison prompt "Old style AMD Opteron NUMA detection" 15935da0ef9aSTejun Heo depends on X86_64 && NUMA && PCI 1594a7f7f624SMasahiro Yamada help 1595eec1d4faSHans Rosenfeld Enable AMD NUMA node topology detection. You should say Y here if 1596eec1d4faSHans Rosenfeld you have a multi processor AMD system. This uses an old method to 1597eec1d4faSHans Rosenfeld read the NUMA configuration directly from the builtin Northbridge 1598eec1d4faSHans Rosenfeld of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1599eec1d4faSHans Rosenfeld which also takes priority if both are compiled in. 1600506f1d07SSam Ravnborg 1601506f1d07SSam Ravnborgconfig X86_64_ACPI_NUMA 16023c2362e6SHarvey Harrison def_bool y 16033c2362e6SHarvey Harrison prompt "ACPI NUMA detection" 1604506f1d07SSam Ravnborg depends on X86_64 && NUMA && ACPI && PCI 1605506f1d07SSam Ravnborg select ACPI_NUMA 1606a7f7f624SMasahiro Yamada help 1607506f1d07SSam Ravnborg Enable ACPI SRAT based node topology detection. 1608506f1d07SSam Ravnborg 1609506f1d07SSam Ravnborgconfig NUMA_EMU 1610506f1d07SSam Ravnborg bool "NUMA emulation" 16111b7e03efSTejun Heo depends on NUMA 1612a7f7f624SMasahiro Yamada help 1613506f1d07SSam Ravnborg Enable NUMA emulation. A flat machine will be split 1614506f1d07SSam Ravnborg into virtual nodes when booted with "numa=fake=N", where N is the 1615506f1d07SSam Ravnborg number of nodes. This is only useful for debugging. 1616506f1d07SSam Ravnborg 1617506f1d07SSam Ravnborgconfig NODES_SHIFT 1618d25e26b6SLinus Torvalds int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 161951591e31SDavid Rientjes range 1 10 162051591e31SDavid Rientjes default "10" if MAXSMP 1621506f1d07SSam Ravnborg default "6" if X86_64 1622506f1d07SSam Ravnborg default "3" 1623a9ee6cf5SMike Rapoport depends on NUMA 1624a7f7f624SMasahiro Yamada help 16251184dc2fSMike Travis Specify the maximum number of NUMA Nodes available on the target 1626692105b8SMatt LaPlante system. Increases memory reserved to accommodate various tables. 1627506f1d07SSam Ravnborg 1628506f1d07SSam Ravnborgconfig ARCH_FLATMEM_ENABLE 1629506f1d07SSam Ravnborg def_bool y 16303b16651fSTejun Heo depends on X86_32 && !NUMA 1631506f1d07SSam Ravnborg 1632506f1d07SSam Ravnborgconfig ARCH_SPARSEMEM_ENABLE 1633506f1d07SSam Ravnborg def_bool y 16346ea30386SKees Cook depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1635506f1d07SSam Ravnborg select SPARSEMEM_STATIC if X86_32 1636506f1d07SSam Ravnborg select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1637506f1d07SSam Ravnborg 16383b16651fSTejun Heoconfig ARCH_SPARSEMEM_DEFAULT 16396ad57f7fSMike Rapoport def_bool X86_64 || (NUMA && X86_32) 16403b16651fSTejun Heo 1641506f1d07SSam Ravnborgconfig ARCH_SELECT_MEMORY_MODEL 1642506f1d07SSam Ravnborg def_bool y 16434eda2bc3SDavid Hildenbrand depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE 1644506f1d07SSam Ravnborg 1645506f1d07SSam Ravnborgconfig ARCH_MEMORY_PROBE 1646a0842b70SToshi Kani bool "Enable sysfs memory/probe interface" 16475c11f00bSDavid Hildenbrand depends on MEMORY_HOTPLUG 1648a0842b70SToshi Kani help 1649a0842b70SToshi Kani This option enables a sysfs memory/probe interface for testing. 1650cb1aaebeSMauro Carvalho Chehab See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1651a0842b70SToshi Kani If you are unsure how to answer this question, answer N. 1652506f1d07SSam Ravnborg 16533b16651fSTejun Heoconfig ARCH_PROC_KCORE_TEXT 16543b16651fSTejun Heo def_bool y 16553b16651fSTejun Heo depends on X86_64 && PROC_KCORE 16563b16651fSTejun Heo 1657a29815a3SAvi Kivityconfig ILLEGAL_POINTER_VALUE 1658a29815a3SAvi Kivity hex 1659a29815a3SAvi Kivity default 0 if X86_32 1660a29815a3SAvi Kivity default 0xdead000000000000 if X86_64 1661a29815a3SAvi Kivity 16627a67832cSDan Williamsconfig X86_PMEM_LEGACY_DEVICE 16637a67832cSDan Williams bool 16647a67832cSDan Williams 1665ec776ef6SChristoph Hellwigconfig X86_PMEM_LEGACY 16667a67832cSDan Williams tristate "Support non-standard NVDIMMs and ADR protected memory" 16679f53f9faSDan Williams depends on PHYS_ADDR_T_64BIT 16689f53f9faSDan Williams depends on BLK_DEV 16697a67832cSDan Williams select X86_PMEM_LEGACY_DEVICE 16707b27a862SDan Williams select NUMA_KEEP_MEMINFO if NUMA 16719f53f9faSDan Williams select LIBNVDIMM 1672ec776ef6SChristoph Hellwig help 1673ec776ef6SChristoph Hellwig Treat memory marked using the non-standard e820 type of 12 as used 1674ec776ef6SChristoph Hellwig by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1675ec776ef6SChristoph Hellwig The kernel will offer these regions to the 'pmem' driver so 1676ec776ef6SChristoph Hellwig they can be used for persistent storage. 1677ec776ef6SChristoph Hellwig 1678ec776ef6SChristoph Hellwig Say Y if unsure. 1679ec776ef6SChristoph Hellwig 1680506f1d07SSam Ravnborgconfig HIGHPTE 1681506f1d07SSam Ravnborg bool "Allocate 3rd-level pagetables from highmem" 16826fc108a0SJan Beulich depends on HIGHMEM 1683a7f7f624SMasahiro Yamada help 1684506f1d07SSam Ravnborg The VM uses one page table entry for each page of physical memory. 1685506f1d07SSam Ravnborg For systems with a lot of RAM, this can be wasteful of precious 1686506f1d07SSam Ravnborg low memory. Setting this option will put user-space page table 1687506f1d07SSam Ravnborg entries in high memory. 1688506f1d07SSam Ravnborg 16899f077871SJeremy Fitzhardingeconfig X86_CHECK_BIOS_CORRUPTION 16909f077871SJeremy Fitzhardinge bool "Check for low memory corruption" 1691a7f7f624SMasahiro Yamada help 16929f077871SJeremy Fitzhardinge Periodically check for memory corruption in low memory, which 16939f077871SJeremy Fitzhardinge is suspected to be caused by BIOS. Even when enabled in the 16949f077871SJeremy Fitzhardinge configuration, it is disabled at runtime. Enable it by 16959f077871SJeremy Fitzhardinge setting "memory_corruption_check=1" on the kernel command 16969f077871SJeremy Fitzhardinge line. By default it scans the low 64k of memory every 60 16979f077871SJeremy Fitzhardinge seconds; see the memory_corruption_check_size and 16989f077871SJeremy Fitzhardinge memory_corruption_check_period parameters in 16998c27ceffSMauro Carvalho Chehab Documentation/admin-guide/kernel-parameters.rst to adjust this. 17009f077871SJeremy Fitzhardinge 17019f077871SJeremy Fitzhardinge When enabled with the default parameters, this option has 17029f077871SJeremy Fitzhardinge almost no overhead, as it reserves a relatively small amount 17039f077871SJeremy Fitzhardinge of memory and scans it infrequently. It both detects corruption 17049f077871SJeremy Fitzhardinge and prevents it from affecting the running system. 17059f077871SJeremy Fitzhardinge 17069f077871SJeremy Fitzhardinge It is, however, intended as a diagnostic tool; if repeatable 17079f077871SJeremy Fitzhardinge BIOS-originated corruption always affects the same memory, 17089f077871SJeremy Fitzhardinge you can use memmap= to prevent the kernel from using that 17099f077871SJeremy Fitzhardinge memory. 17109f077871SJeremy Fitzhardinge 1711c885df50SJeremy Fitzhardingeconfig X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1712c885df50SJeremy Fitzhardinge bool "Set the default setting of memory_corruption_check" 1713c885df50SJeremy Fitzhardinge depends on X86_CHECK_BIOS_CORRUPTION 1714c885df50SJeremy Fitzhardinge default y 1715a7f7f624SMasahiro Yamada help 1716c885df50SJeremy Fitzhardinge Set whether the default state of memory_corruption_check is 1717c885df50SJeremy Fitzhardinge on or off. 1718c885df50SJeremy Fitzhardinge 1719506f1d07SSam Ravnborgconfig MATH_EMULATION 1720506f1d07SSam Ravnborg bool 1721a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 172287d6021bSArnd Bergmann prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1723a7f7f624SMasahiro Yamada help 1724506f1d07SSam Ravnborg Linux can emulate a math coprocessor (used for floating point 1725506f1d07SSam Ravnborg operations) if you don't have one. 486DX and Pentium processors have 1726506f1d07SSam Ravnborg a math coprocessor built in, 486SX and 386 do not, unless you added 1727506f1d07SSam Ravnborg a 487DX or 387, respectively. (The messages during boot time can 1728506f1d07SSam Ravnborg give you some hints here ["man dmesg"].) Everyone needs either a 1729506f1d07SSam Ravnborg coprocessor or this emulation. 1730506f1d07SSam Ravnborg 1731506f1d07SSam Ravnborg If you don't have a math coprocessor, you need to say Y here; if you 1732506f1d07SSam Ravnborg say Y here even though you have a coprocessor, the coprocessor will 1733506f1d07SSam Ravnborg be used nevertheless. (This behavior can be changed with the kernel 1734506f1d07SSam Ravnborg command line option "no387", which comes handy if your coprocessor 1735506f1d07SSam Ravnborg is broken. Try "man bootparam" or see the documentation of your boot 1736506f1d07SSam Ravnborg loader (lilo or loadlin) about how to pass options to the kernel at 1737506f1d07SSam Ravnborg boot time.) This means that it is a good idea to say Y here if you 1738506f1d07SSam Ravnborg intend to use this kernel on different machines. 1739506f1d07SSam Ravnborg 1740506f1d07SSam Ravnborg More information about the internals of the Linux math coprocessor 1741506f1d07SSam Ravnborg emulation can be found in <file:arch/x86/math-emu/README>. 1742506f1d07SSam Ravnborg 1743506f1d07SSam Ravnborg If you are not sure, say Y; apart from resulting in a 66 KB bigger 1744506f1d07SSam Ravnborg kernel, it won't hurt. 1745506f1d07SSam Ravnborg 1746506f1d07SSam Ravnborgconfig MTRR 17476fc108a0SJan Beulich def_bool y 17486a108a14SDavid Rientjes prompt "MTRR (Memory Type Range Register) support" if EXPERT 1749a7f7f624SMasahiro Yamada help 1750506f1d07SSam Ravnborg On Intel P6 family processors (Pentium Pro, Pentium II and later) 1751506f1d07SSam Ravnborg the Memory Type Range Registers (MTRRs) may be used to control 1752506f1d07SSam Ravnborg processor access to memory ranges. This is most useful if you have 1753506f1d07SSam Ravnborg a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1754506f1d07SSam Ravnborg allows bus write transfers to be combined into a larger transfer 1755506f1d07SSam Ravnborg before bursting over the PCI/AGP bus. This can increase performance 1756506f1d07SSam Ravnborg of image write operations 2.5 times or more. Saying Y here creates a 1757506f1d07SSam Ravnborg /proc/mtrr file which may be used to manipulate your processor's 1758506f1d07SSam Ravnborg MTRRs. Typically the X server should use this. 1759506f1d07SSam Ravnborg 1760506f1d07SSam Ravnborg This code has a reasonably generic interface so that similar 1761506f1d07SSam Ravnborg control registers on other processors can be easily supported 1762506f1d07SSam Ravnborg as well: 1763506f1d07SSam Ravnborg 1764506f1d07SSam Ravnborg The Cyrix 6x86, 6x86MX and M II processors have Address Range 1765506f1d07SSam Ravnborg Registers (ARRs) which provide a similar functionality to MTRRs. For 1766506f1d07SSam Ravnborg these, the ARRs are used to emulate the MTRRs. 1767506f1d07SSam Ravnborg The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1768506f1d07SSam Ravnborg MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1769506f1d07SSam Ravnborg write-combining. All of these processors are supported by this code 1770506f1d07SSam Ravnborg and it makes sense to say Y here if you have one of them. 1771506f1d07SSam Ravnborg 1772506f1d07SSam Ravnborg Saying Y here also fixes a problem with buggy SMP BIOSes which only 1773506f1d07SSam Ravnborg set the MTRRs for the boot CPU and not for the secondary CPUs. This 1774506f1d07SSam Ravnborg can lead to all sorts of problems, so it's good to say Y here. 1775506f1d07SSam Ravnborg 1776506f1d07SSam Ravnborg You can safely say Y even if your machine doesn't have MTRRs, you'll 1777506f1d07SSam Ravnborg just add about 9 KB to your kernel. 1778506f1d07SSam Ravnborg 1779ff61f079SJonathan Corbet See <file:Documentation/arch/x86/mtrr.rst> for more information. 1780506f1d07SSam Ravnborg 178195ffa243SYinghai Luconfig MTRR_SANITIZER 17822ffb3501SYinghai Lu def_bool y 178395ffa243SYinghai Lu prompt "MTRR cleanup support" 178495ffa243SYinghai Lu depends on MTRR 1785a7f7f624SMasahiro Yamada help 1786aba3728cSThomas Gleixner Convert MTRR layout from continuous to discrete, so X drivers can 1787aba3728cSThomas Gleixner add writeback entries. 178895ffa243SYinghai Lu 1789aba3728cSThomas Gleixner Can be disabled with disable_mtrr_cleanup on the kernel command line. 1790692105b8SMatt LaPlante The largest mtrr entry size for a continuous block can be set with 1791aba3728cSThomas Gleixner mtrr_chunk_size. 179295ffa243SYinghai Lu 17932ffb3501SYinghai Lu If unsure, say Y. 179495ffa243SYinghai Lu 179595ffa243SYinghai Luconfig MTRR_SANITIZER_ENABLE_DEFAULT 1796f5098d62SYinghai Lu int "MTRR cleanup enable value (0-1)" 1797f5098d62SYinghai Lu range 0 1 1798f5098d62SYinghai Lu default "0" 179995ffa243SYinghai Lu depends on MTRR_SANITIZER 1800a7f7f624SMasahiro Yamada help 1801f5098d62SYinghai Lu Enable mtrr cleanup default value 180295ffa243SYinghai Lu 180312031a62SYinghai Luconfig MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 180412031a62SYinghai Lu int "MTRR cleanup spare reg num (0-7)" 180512031a62SYinghai Lu range 0 7 180612031a62SYinghai Lu default "1" 180712031a62SYinghai Lu depends on MTRR_SANITIZER 1808a7f7f624SMasahiro Yamada help 180912031a62SYinghai Lu mtrr cleanup spare entries default, it can be changed via 1810aba3728cSThomas Gleixner mtrr_spare_reg_nr=N on the kernel command line. 181112031a62SYinghai Lu 18122e5d9c85Svenkatesh.pallipadi@intel.comconfig X86_PAT 18136fc108a0SJan Beulich def_bool y 18146a108a14SDavid Rientjes prompt "x86 PAT support" if EXPERT 18152a8a2719SIngo Molnar depends on MTRR 1816a7f7f624SMasahiro Yamada help 18172e5d9c85Svenkatesh.pallipadi@intel.com Use PAT attributes to setup page level cache control. 1818042b78e4SVenki Pallipadi 18192e5d9c85Svenkatesh.pallipadi@intel.com PATs are the modern equivalents of MTRRs and are much more 18202e5d9c85Svenkatesh.pallipadi@intel.com flexible than MTRRs. 18212e5d9c85Svenkatesh.pallipadi@intel.com 18222e5d9c85Svenkatesh.pallipadi@intel.com Say N here if you see bootup problems (boot crash, boot hang, 1823042b78e4SVenki Pallipadi spontaneous reboots) or a non-working video driver. 18242e5d9c85Svenkatesh.pallipadi@intel.com 18252e5d9c85Svenkatesh.pallipadi@intel.com If unsure, say Y. 18262e5d9c85Svenkatesh.pallipadi@intel.com 182746cf98cdSVenkatesh Pallipadiconfig ARCH_USES_PG_UNCACHED 182846cf98cdSVenkatesh Pallipadi def_bool y 182946cf98cdSVenkatesh Pallipadi depends on X86_PAT 183046cf98cdSVenkatesh Pallipadi 1831b971880fSBabu Mogerconfig X86_UMIP 1832796ebc81SRicardo Neri def_bool y 1833b971880fSBabu Moger prompt "User Mode Instruction Prevention" if EXPERT 1834a7f7f624SMasahiro Yamada help 1835b971880fSBabu Moger User Mode Instruction Prevention (UMIP) is a security feature in 1836b971880fSBabu Moger some x86 processors. If enabled, a general protection fault is 1837b971880fSBabu Moger issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1838b971880fSBabu Moger executed in user mode. These instructions unnecessarily expose 1839b971880fSBabu Moger information about the hardware state. 1840796ebc81SRicardo Neri 1841796ebc81SRicardo Neri The vast majority of applications do not use these instructions. 1842796ebc81SRicardo Neri For the very few that do, software emulation is provided in 1843796ebc81SRicardo Neri specific cases in protected and virtual-8086 modes. Emulated 1844796ebc81SRicardo Neri results are dummy. 1845aa35f896SRicardo Neri 1846156ff4a5SPeter Zijlstraconfig CC_HAS_IBT 1847156ff4a5SPeter Zijlstra # GCC >= 9 and binutils >= 2.29 1848156ff4a5SPeter Zijlstra # Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654 1849156ff4a5SPeter Zijlstra # Clang/LLVM >= 14 1850262448f3SNathan Chancellor # https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f 1851262448f3SNathan Chancellor # https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332 1852156ff4a5SPeter Zijlstra def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \ 1853262448f3SNathan Chancellor (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \ 1854156ff4a5SPeter Zijlstra $(as-instr,endbr64) 1855156ff4a5SPeter Zijlstra 1856156ff4a5SPeter Zijlstraconfig X86_KERNEL_IBT 1857156ff4a5SPeter Zijlstra prompt "Indirect Branch Tracking" 18584fd5f70cSKees Cook def_bool y 185903f16cd0SJosh Poimboeuf depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL 1860f6a2c2b2SNathan Chancellor # https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f 1861f6a2c2b2SNathan Chancellor depends on !LD_IS_LLD || LLD_VERSION >= 140000 186203f16cd0SJosh Poimboeuf select OBJTOOL 1863156ff4a5SPeter Zijlstra help 1864156ff4a5SPeter Zijlstra Build the kernel with support for Indirect Branch Tracking, a 1865156ff4a5SPeter Zijlstra hardware support course-grain forward-edge Control Flow Integrity 1866156ff4a5SPeter Zijlstra protection. It enforces that all indirect calls must land on 1867156ff4a5SPeter Zijlstra an ENDBR instruction, as such, the compiler will instrument the 1868156ff4a5SPeter Zijlstra code with them to make this happen. 1869156ff4a5SPeter Zijlstra 1870ed53a0d9SPeter Zijlstra In addition to building the kernel with IBT, seal all functions that 18714cdfc11bSNur Hussein are not indirect call targets, avoiding them ever becoming one. 1872ed53a0d9SPeter Zijlstra 1873ed53a0d9SPeter Zijlstra This requires LTO like objtool runs and will slow down the build. It 1874ed53a0d9SPeter Zijlstra does significantly reduce the number of ENDBR instructions in the 1875ed53a0d9SPeter Zijlstra kernel image. 1876ed53a0d9SPeter Zijlstra 187735e97790SDave Hansenconfig X86_INTEL_MEMORY_PROTECTION_KEYS 187838f3e775SBabu Moger prompt "Memory Protection Keys" 187935e97790SDave Hansen def_bool y 1880284244a9SDave Hansen # Note: only available in 64-bit mode 188138f3e775SBabu Moger depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 188252c8e601SIngo Molnar select ARCH_USES_HIGH_VMA_FLAGS 188352c8e601SIngo Molnar select ARCH_HAS_PKEYS 1884a7f7f624SMasahiro Yamada help 1885284244a9SDave Hansen Memory Protection Keys provides a mechanism for enforcing 1886284244a9SDave Hansen page-based protections, but without requiring modification of the 1887284244a9SDave Hansen page tables when an application changes protection domains. 1888284244a9SDave Hansen 18891eecbcdcSMauro Carvalho Chehab For details, see Documentation/core-api/protection-keys.rst 1890284244a9SDave Hansen 1891284244a9SDave Hansen If unsure, say y. 189235e97790SDave Hansen 1893db616173SMichal Hockochoice 1894db616173SMichal Hocko prompt "TSX enable mode" 1895db616173SMichal Hocko depends on CPU_SUP_INTEL 1896db616173SMichal Hocko default X86_INTEL_TSX_MODE_OFF 1897db616173SMichal Hocko help 1898db616173SMichal Hocko Intel's TSX (Transactional Synchronization Extensions) feature 1899db616173SMichal Hocko allows to optimize locking protocols through lock elision which 1900db616173SMichal Hocko can lead to a noticeable performance boost. 1901db616173SMichal Hocko 1902db616173SMichal Hocko On the other hand it has been shown that TSX can be exploited 1903db616173SMichal Hocko to form side channel attacks (e.g. TAA) and chances are there 1904db616173SMichal Hocko will be more of those attacks discovered in the future. 1905db616173SMichal Hocko 1906db616173SMichal Hocko Therefore TSX is not enabled by default (aka tsx=off). An admin 1907db616173SMichal Hocko might override this decision by tsx=on the command line parameter. 1908db616173SMichal Hocko Even with TSX enabled, the kernel will attempt to enable the best 1909db616173SMichal Hocko possible TAA mitigation setting depending on the microcode available 1910db616173SMichal Hocko for the particular machine. 1911db616173SMichal Hocko 1912db616173SMichal Hocko This option allows to set the default tsx mode between tsx=on, =off 1913db616173SMichal Hocko and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1914db616173SMichal Hocko details. 1915db616173SMichal Hocko 1916db616173SMichal Hocko Say off if not sure, auto if TSX is in use but it should be used on safe 1917db616173SMichal Hocko platforms or on if TSX is in use and the security aspect of tsx is not 1918db616173SMichal Hocko relevant. 1919db616173SMichal Hocko 1920db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_OFF 1921db616173SMichal Hocko bool "off" 1922db616173SMichal Hocko help 1923db616173SMichal Hocko TSX is disabled if possible - equals to tsx=off command line parameter. 1924db616173SMichal Hocko 1925db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_ON 1926db616173SMichal Hocko bool "on" 1927db616173SMichal Hocko help 1928db616173SMichal Hocko TSX is always enabled on TSX capable HW - equals the tsx=on command 1929db616173SMichal Hocko line parameter. 1930db616173SMichal Hocko 1931db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_AUTO 1932db616173SMichal Hocko bool "auto" 1933db616173SMichal Hocko help 1934db616173SMichal Hocko TSX is enabled on TSX capable HW that is believed to be safe against 1935db616173SMichal Hocko side channel attacks- equals the tsx=auto command line parameter. 1936db616173SMichal Hockoendchoice 1937db616173SMichal Hocko 1938e7e05452SSean Christophersonconfig X86_SGX 1939e7e05452SSean Christopherson bool "Software Guard eXtensions (SGX)" 1940b8d1d163SDaniel Sneddon depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC 1941e7e05452SSean Christopherson depends on CRYPTO=y 1942e7e05452SSean Christopherson depends on CRYPTO_SHA256=y 1943e7e05452SSean Christopherson select MMU_NOTIFIER 1944901ddbb9SJarkko Sakkinen select NUMA_KEEP_MEMINFO if NUMA 194540e0e784STony Luck select XARRAY_MULTI 1946e7e05452SSean Christopherson help 1947e7e05452SSean Christopherson Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1948e7e05452SSean Christopherson that can be used by applications to set aside private regions of code 1949e7e05452SSean Christopherson and data, referred to as enclaves. An enclave's private memory can 1950e7e05452SSean Christopherson only be accessed by code running within the enclave. Accesses from 1951e7e05452SSean Christopherson outside the enclave, including other enclaves, are disallowed by 1952e7e05452SSean Christopherson hardware. 1953e7e05452SSean Christopherson 1954e7e05452SSean Christopherson If unsure, say N. 1955e7e05452SSean Christopherson 1956506f1d07SSam Ravnborgconfig EFI 19579ba16087SJan Beulich bool "EFI runtime service support" 19585b83683fSHuang, Ying depends on ACPI 1959f6ce5002SSergey Vlasov select UCS2_STRING 1960022ee6c5SArd Biesheuvel select EFI_RUNTIME_WRAPPERS 19611ff2fc02STom Lendacky select ARCH_USE_MEMREMAP_PROT 1962a7f7f624SMasahiro Yamada help 19638b2cb7a8SHuang, Ying This enables the kernel to use EFI runtime services that are 1964506f1d07SSam Ravnborg available (such as the EFI variable services). 1965506f1d07SSam Ravnborg 19668b2cb7a8SHuang, Ying This option is only useful on systems that have EFI firmware. 19678b2cb7a8SHuang, Ying In addition, you should use the latest ELILO loader available 19688b2cb7a8SHuang, Ying at <http://elilo.sourceforge.net> in order to take advantage 19698b2cb7a8SHuang, Ying of EFI runtime services. However, even with this option, the 19708b2cb7a8SHuang, Ying resultant kernel should continue to boot on existing non-EFI 19718b2cb7a8SHuang, Ying platforms. 1972506f1d07SSam Ravnborg 1973291f3632SMatt Flemingconfig EFI_STUB 1974291f3632SMatt Fleming bool "EFI stub support" 1975c6dbd3e5SPeter Zijlstra depends on EFI 19767b2a583aSMatt Fleming select RELOCATABLE 1977a7f7f624SMasahiro Yamada help 1978291f3632SMatt Fleming This kernel feature allows a bzImage to be loaded directly 1979291f3632SMatt Fleming by EFI firmware without the use of a bootloader. 1980291f3632SMatt Fleming 19814f4cfa6cSMauro Carvalho Chehab See Documentation/admin-guide/efi-stub.rst for more information. 19820c759662SMatt Fleming 1983cc3fdda2SArd Biesheuvelconfig EFI_HANDOVER_PROTOCOL 1984cc3fdda2SArd Biesheuvel bool "EFI handover protocol (DEPRECATED)" 1985cc3fdda2SArd Biesheuvel depends on EFI_STUB 1986cc3fdda2SArd Biesheuvel default y 1987cc3fdda2SArd Biesheuvel help 1988cc3fdda2SArd Biesheuvel Select this in order to include support for the deprecated EFI 1989cc3fdda2SArd Biesheuvel handover protocol, which defines alternative entry points into the 1990cc3fdda2SArd Biesheuvel EFI stub. This is a practice that has no basis in the UEFI 1991cc3fdda2SArd Biesheuvel specification, and requires a priori knowledge on the part of the 1992cc3fdda2SArd Biesheuvel bootloader about Linux/x86 specific ways of passing the command line 1993cc3fdda2SArd Biesheuvel and initrd, and where in memory those assets may be loaded. 1994cc3fdda2SArd Biesheuvel 1995cc3fdda2SArd Biesheuvel If in doubt, say Y. Even though the corresponding support is not 1996cc3fdda2SArd Biesheuvel present in upstream GRUB or other bootloaders, most distros build 1997cc3fdda2SArd Biesheuvel GRUB with numerous downstream patches applied, and may rely on the 1998cc3fdda2SArd Biesheuvel handover protocol as as result. 1999cc3fdda2SArd Biesheuvel 20007d453eeeSMatt Flemingconfig EFI_MIXED 20017d453eeeSMatt Fleming bool "EFI mixed-mode support" 20027d453eeeSMatt Fleming depends on EFI_STUB && X86_64 2003a7f7f624SMasahiro Yamada help 20047d453eeeSMatt Fleming Enabling this feature allows a 64-bit kernel to be booted 20057d453eeeSMatt Fleming on a 32-bit firmware, provided that your CPU supports 64-bit 20067d453eeeSMatt Fleming mode. 20077d453eeeSMatt Fleming 20087d453eeeSMatt Fleming Note that it is not possible to boot a mixed-mode enabled 20097d453eeeSMatt Fleming kernel via the EFI boot stub - a bootloader that supports 20107d453eeeSMatt Fleming the EFI handover protocol must be used. 20117d453eeeSMatt Fleming 20127d453eeeSMatt Fleming If unsure, say N. 20137d453eeeSMatt Fleming 20144059ba65SArd Biesheuvelconfig EFI_FAKE_MEMMAP 20154059ba65SArd Biesheuvel bool "Enable EFI fake memory map" 20164059ba65SArd Biesheuvel depends on EFI 20174059ba65SArd Biesheuvel help 20184059ba65SArd Biesheuvel Saying Y here will enable "efi_fake_mem" boot option. By specifying 20194059ba65SArd Biesheuvel this parameter, you can add arbitrary attribute to specific memory 20204059ba65SArd Biesheuvel range by updating original (firmware provided) EFI memmap. This is 20214059ba65SArd Biesheuvel useful for debugging of EFI memmap related feature, e.g., Address 20224059ba65SArd Biesheuvel Range Mirroring feature. 20234059ba65SArd Biesheuvel 20244059ba65SArd Biesheuvelconfig EFI_MAX_FAKE_MEM 20254059ba65SArd Biesheuvel int "maximum allowable number of ranges in efi_fake_mem boot option" 20264059ba65SArd Biesheuvel depends on EFI_FAKE_MEMMAP 20274059ba65SArd Biesheuvel range 1 128 20284059ba65SArd Biesheuvel default 8 20294059ba65SArd Biesheuvel help 20304059ba65SArd Biesheuvel Maximum allowable number of ranges in efi_fake_mem boot option. 20314059ba65SArd Biesheuvel Ranges can be set up to this value using comma-separated list. 20324059ba65SArd Biesheuvel The default value is 8. 20334059ba65SArd Biesheuvel 20341fff234dSArd Biesheuvelconfig EFI_RUNTIME_MAP 20351fff234dSArd Biesheuvel bool "Export EFI runtime maps to sysfs" if EXPERT 20361fff234dSArd Biesheuvel depends on EFI 20371fff234dSArd Biesheuvel default KEXEC_CORE 20381fff234dSArd Biesheuvel help 20391fff234dSArd Biesheuvel Export EFI runtime memory regions to /sys/firmware/efi/runtime-map. 20401fff234dSArd Biesheuvel That memory map is required by the 2nd kernel to set up EFI virtual 20411fff234dSArd Biesheuvel mappings after kexec, but can also be used for debugging purposes. 20421fff234dSArd Biesheuvel 20431fff234dSArd Biesheuvel See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map. 20441fff234dSArd Biesheuvel 20458636a1f9SMasahiro Yamadasource "kernel/Kconfig.hz" 2046506f1d07SSam Ravnborg 2047506f1d07SSam Ravnborgconfig KEXEC 2048506f1d07SSam Ravnborg bool "kexec system call" 20492965faa5SDave Young select KEXEC_CORE 2050a7f7f624SMasahiro Yamada help 2051506f1d07SSam Ravnborg kexec is a system call that implements the ability to shutdown your 2052506f1d07SSam Ravnborg current kernel, and to start another kernel. It is like a reboot 2053506f1d07SSam Ravnborg but it is independent of the system firmware. And like a reboot 2054506f1d07SSam Ravnborg you can start any kernel with it, not just Linux. 2055506f1d07SSam Ravnborg 2056506f1d07SSam Ravnborg The name comes from the similarity to the exec system call. 2057506f1d07SSam Ravnborg 2058506f1d07SSam Ravnborg It is an ongoing process to be certain the hardware in a machine 2059506f1d07SSam Ravnborg is properly shutdown, so do not be surprised if this code does not 2060bf220695SGeert Uytterhoeven initially work for you. As of this writing the exact hardware 2061bf220695SGeert Uytterhoeven interface is strongly in flux, so no good recommendation can be 2062bf220695SGeert Uytterhoeven made. 2063506f1d07SSam Ravnborg 206474ca317cSVivek Goyalconfig KEXEC_FILE 206574ca317cSVivek Goyal bool "kexec file based system call" 20662965faa5SDave Young select KEXEC_CORE 2067b69a2afdSJonathan McDowell select HAVE_IMA_KEXEC if IMA 206874ca317cSVivek Goyal depends on X86_64 206974ca317cSVivek Goyal depends on CRYPTO=y 207074ca317cSVivek Goyal depends on CRYPTO_SHA256=y 2071a7f7f624SMasahiro Yamada help 207274ca317cSVivek Goyal This is new version of kexec system call. This system call is 207374ca317cSVivek Goyal file based and takes file descriptors as system call argument 207474ca317cSVivek Goyal for kernel and initramfs as opposed to list of segments as 207574ca317cSVivek Goyal accepted by previous system call. 207674ca317cSVivek Goyal 2077b799a09fSAKASHI Takahiroconfig ARCH_HAS_KEXEC_PURGATORY 2078b799a09fSAKASHI Takahiro def_bool KEXEC_FILE 2079b799a09fSAKASHI Takahiro 208099d5cadfSJiri Bohacconfig KEXEC_SIG 20818e7d8381SVivek Goyal bool "Verify kernel signature during kexec_file_load() syscall" 208274ca317cSVivek Goyal depends on KEXEC_FILE 2083a7f7f624SMasahiro Yamada help 208499d5cadfSJiri Bohac 208599d5cadfSJiri Bohac This option makes the kexec_file_load() syscall check for a valid 208699d5cadfSJiri Bohac signature of the kernel image. The image can still be loaded without 208799d5cadfSJiri Bohac a valid signature unless you also enable KEXEC_SIG_FORCE, though if 208899d5cadfSJiri Bohac there's a signature that we can check, then it must be valid. 208999d5cadfSJiri Bohac 209099d5cadfSJiri Bohac In addition to this option, you need to enable signature 209199d5cadfSJiri Bohac verification for the corresponding kernel image type being 209299d5cadfSJiri Bohac loaded in order for this to work. 209399d5cadfSJiri Bohac 209499d5cadfSJiri Bohacconfig KEXEC_SIG_FORCE 209599d5cadfSJiri Bohac bool "Require a valid signature in kexec_file_load() syscall" 209699d5cadfSJiri Bohac depends on KEXEC_SIG 2097a7f7f624SMasahiro Yamada help 20988e7d8381SVivek Goyal This option makes kernel signature verification mandatory for 2099d8eb8940SBorislav Petkov the kexec_file_load() syscall. 21008e7d8381SVivek Goyal 21018e7d8381SVivek Goyalconfig KEXEC_BZIMAGE_VERIFY_SIG 21028e7d8381SVivek Goyal bool "Enable bzImage signature verification support" 210399d5cadfSJiri Bohac depends on KEXEC_SIG 21048e7d8381SVivek Goyal depends on SIGNED_PE_FILE_VERIFICATION 21058e7d8381SVivek Goyal select SYSTEM_TRUSTED_KEYRING 2106a7f7f624SMasahiro Yamada help 21078e7d8381SVivek Goyal Enable bzImage signature verification support. 21088e7d8381SVivek Goyal 2109506f1d07SSam Ravnborgconfig CRASH_DUMP 211004b69447SPavel Machek bool "kernel crash dumps" 2111506f1d07SSam Ravnborg depends on X86_64 || (X86_32 && HIGHMEM) 2112a7f7f624SMasahiro Yamada help 2113506f1d07SSam Ravnborg Generate crash dump after being started by kexec. 2114506f1d07SSam Ravnborg This should be normally only set in special crash dump kernels 2115506f1d07SSam Ravnborg which are loaded in the main kernel with kexec-tools into 2116506f1d07SSam Ravnborg a specially reserved region and then later executed after 2117506f1d07SSam Ravnborg a crash by kdump/kexec. The crash dump kernel must be compiled 2118506f1d07SSam Ravnborg to a memory address not used by the main kernel or BIOS using 2119506f1d07SSam Ravnborg PHYSICAL_START, or it must be built as a relocatable image 2120506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y). 2121330d4810SMauro Carvalho Chehab For more details see Documentation/admin-guide/kdump/kdump.rst 2122506f1d07SSam Ravnborg 21233ab83521SHuang Yingconfig KEXEC_JUMP 21246ea30386SKees Cook bool "kexec jump" 2125fee7b0d8SHuang Ying depends on KEXEC && HIBERNATION 2126a7f7f624SMasahiro Yamada help 212789081d17SHuang Ying Jump between original kernel and kexeced kernel and invoke 212889081d17SHuang Ying code in physical address mode via KEXEC 21293ab83521SHuang Ying 2130506f1d07SSam Ravnborgconfig PHYSICAL_START 21316a108a14SDavid Rientjes hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2132ceefccc9SH. Peter Anvin default "0x1000000" 2133a7f7f624SMasahiro Yamada help 2134506f1d07SSam Ravnborg This gives the physical address where the kernel is loaded. 2135506f1d07SSam Ravnborg 2136506f1d07SSam Ravnborg If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2137506f1d07SSam Ravnborg bzImage will decompress itself to above physical address and 2138506f1d07SSam Ravnborg run from there. Otherwise, bzImage will run from the address where 2139506f1d07SSam Ravnborg it has been loaded by the boot loader and will ignore above physical 2140506f1d07SSam Ravnborg address. 2141506f1d07SSam Ravnborg 2142506f1d07SSam Ravnborg In normal kdump cases one does not have to set/change this option 2143506f1d07SSam Ravnborg as now bzImage can be compiled as a completely relocatable image 2144506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2145506f1d07SSam Ravnborg address. This option is mainly useful for the folks who don't want 2146506f1d07SSam Ravnborg to use a bzImage for capturing the crash dump and want to use a 2147506f1d07SSam Ravnborg vmlinux instead. vmlinux is not relocatable hence a kernel needs 2148506f1d07SSam Ravnborg to be specifically compiled to run from a specific memory area 2149506f1d07SSam Ravnborg (normally a reserved region) and this option comes handy. 2150506f1d07SSam Ravnborg 2151ceefccc9SH. Peter Anvin So if you are using bzImage for capturing the crash dump, 2152ceefccc9SH. Peter Anvin leave the value here unchanged to 0x1000000 and set 2153ceefccc9SH. Peter Anvin CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2154ceefccc9SH. Peter Anvin for capturing the crash dump change this value to start of 2155ceefccc9SH. Peter Anvin the reserved region. In other words, it can be set based on 2156ceefccc9SH. Peter Anvin the "X" value as specified in the "crashkernel=YM@XM" 2157ceefccc9SH. Peter Anvin command line boot parameter passed to the panic-ed 2158330d4810SMauro Carvalho Chehab kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2159ceefccc9SH. Peter Anvin for more details about crash dumps. 2160506f1d07SSam Ravnborg 2161506f1d07SSam Ravnborg Usage of bzImage for capturing the crash dump is recommended as 2162506f1d07SSam Ravnborg one does not have to build two kernels. Same kernel can be used 2163506f1d07SSam Ravnborg as production kernel and capture kernel. Above option should have 2164506f1d07SSam Ravnborg gone away after relocatable bzImage support is introduced. But it 2165506f1d07SSam Ravnborg is present because there are users out there who continue to use 2166506f1d07SSam Ravnborg vmlinux for dump capture. This option should go away down the 2167506f1d07SSam Ravnborg line. 2168506f1d07SSam Ravnborg 2169506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2170506f1d07SSam Ravnborg 2171506f1d07SSam Ravnborgconfig RELOCATABLE 217226717808SH. Peter Anvin bool "Build a relocatable kernel" 217326717808SH. Peter Anvin default y 2174a7f7f624SMasahiro Yamada help 2175506f1d07SSam Ravnborg This builds a kernel image that retains relocation information 2176506f1d07SSam Ravnborg so it can be loaded someplace besides the default 1MB. 2177506f1d07SSam Ravnborg The relocations tend to make the kernel binary about 10% larger, 2178506f1d07SSam Ravnborg but are discarded at runtime. 2179506f1d07SSam Ravnborg 2180506f1d07SSam Ravnborg One use is for the kexec on panic case where the recovery kernel 2181506f1d07SSam Ravnborg must live at a different physical address than the primary 2182506f1d07SSam Ravnborg kernel. 2183506f1d07SSam Ravnborg 2184506f1d07SSam Ravnborg Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2185506f1d07SSam Ravnborg it has been loaded at and the compile time physical address 21868ab3820fSKees Cook (CONFIG_PHYSICAL_START) is used as the minimum location. 2187506f1d07SSam Ravnborg 21888ab3820fSKees Cookconfig RANDOMIZE_BASE 2189e8581e3dSBaoquan He bool "Randomize the address of the kernel image (KASLR)" 21908ab3820fSKees Cook depends on RELOCATABLE 21916807c846SIngo Molnar default y 2192a7f7f624SMasahiro Yamada help 2193e8581e3dSBaoquan He In support of Kernel Address Space Layout Randomization (KASLR), 2194e8581e3dSBaoquan He this randomizes the physical address at which the kernel image 2195e8581e3dSBaoquan He is decompressed and the virtual address where the kernel 2196e8581e3dSBaoquan He image is mapped, as a security feature that deters exploit 2197e8581e3dSBaoquan He attempts relying on knowledge of the location of kernel 2198e8581e3dSBaoquan He code internals. 2199e8581e3dSBaoquan He 2200ed9f007eSKees Cook On 64-bit, the kernel physical and virtual addresses are 2201ed9f007eSKees Cook randomized separately. The physical address will be anywhere 2202ed9f007eSKees Cook between 16MB and the top of physical memory (up to 64TB). The 2203ed9f007eSKees Cook virtual address will be randomized from 16MB up to 1GB (9 bits 2204ed9f007eSKees Cook of entropy). Note that this also reduces the memory space 2205ed9f007eSKees Cook available to kernel modules from 1.5GB to 1GB. 2206ed9f007eSKees Cook 2207ed9f007eSKees Cook On 32-bit, the kernel physical and virtual addresses are 2208ed9f007eSKees Cook randomized together. They will be randomized from 16MB up to 2209ed9f007eSKees Cook 512MB (8 bits of entropy). 22108ab3820fSKees Cook 2211a653f356SKees Cook Entropy is generated using the RDRAND instruction if it is 2212e8581e3dSBaoquan He supported. If RDTSC is supported, its value is mixed into 2213e8581e3dSBaoquan He the entropy pool as well. If neither RDRAND nor RDTSC are 2214ed9f007eSKees Cook supported, then entropy is read from the i8254 timer. The 2215ed9f007eSKees Cook usable entropy is limited by the kernel being built using 2216ed9f007eSKees Cook 2GB addressing, and that PHYSICAL_ALIGN must be at a 2217ed9f007eSKees Cook minimum of 2MB. As a result, only 10 bits of entropy are 2218ed9f007eSKees Cook theoretically possible, but the implementations are further 2219ed9f007eSKees Cook limited due to memory layouts. 2220e8581e3dSBaoquan He 22216807c846SIngo Molnar If unsure, say Y. 2222da2b6fb9SKees Cook 22238ab3820fSKees Cook# Relocation on x86 needs some additional build support 2224845adf72SH. Peter Anvinconfig X86_NEED_RELOCS 2225845adf72SH. Peter Anvin def_bool y 22268ab3820fSKees Cook depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2227845adf72SH. Peter Anvin 2228506f1d07SSam Ravnborgconfig PHYSICAL_ALIGN 2229a0215061SKees Cook hex "Alignment value to which kernel should be aligned" 22308ab3820fSKees Cook default "0x200000" 2231a0215061SKees Cook range 0x2000 0x1000000 if X86_32 2232a0215061SKees Cook range 0x200000 0x1000000 if X86_64 2233a7f7f624SMasahiro Yamada help 2234506f1d07SSam Ravnborg This value puts the alignment restrictions on physical address 2235506f1d07SSam Ravnborg where kernel is loaded and run from. Kernel is compiled for an 2236506f1d07SSam Ravnborg address which meets above alignment restriction. 2237506f1d07SSam Ravnborg 2238506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2239506f1d07SSam Ravnborg CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2240506f1d07SSam Ravnborg address aligned to above value and run from there. 2241506f1d07SSam Ravnborg 2242506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2243506f1d07SSam Ravnborg CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2244506f1d07SSam Ravnborg load address and decompress itself to the address it has been 2245506f1d07SSam Ravnborg compiled for and run from there. The address for which kernel is 2246506f1d07SSam Ravnborg compiled already meets above alignment restrictions. Hence the 2247506f1d07SSam Ravnborg end result is that kernel runs from a physical address meeting 2248506f1d07SSam Ravnborg above alignment restrictions. 2249506f1d07SSam Ravnborg 2250a0215061SKees Cook On 32-bit this value must be a multiple of 0x2000. On 64-bit 2251a0215061SKees Cook this value must be a multiple of 0x200000. 2252a0215061SKees Cook 2253506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2254506f1d07SSam Ravnborg 2255eedb92abSKirill A. Shutemovconfig DYNAMIC_MEMORY_LAYOUT 2256eedb92abSKirill A. Shutemov bool 2257a7f7f624SMasahiro Yamada help 2258eedb92abSKirill A. Shutemov This option makes base addresses of vmalloc and vmemmap as well as 2259eedb92abSKirill A. Shutemov __PAGE_OFFSET movable during boot. 2260eedb92abSKirill A. Shutemov 22610483e1faSThomas Garnierconfig RANDOMIZE_MEMORY 22620483e1faSThomas Garnier bool "Randomize the kernel memory sections" 22630483e1faSThomas Garnier depends on X86_64 22640483e1faSThomas Garnier depends on RANDOMIZE_BASE 2265eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 22660483e1faSThomas Garnier default RANDOMIZE_BASE 2267a7f7f624SMasahiro Yamada help 22680483e1faSThomas Garnier Randomizes the base virtual address of kernel memory sections 22690483e1faSThomas Garnier (physical memory mapping, vmalloc & vmemmap). This security feature 22700483e1faSThomas Garnier makes exploits relying on predictable memory locations less reliable. 22710483e1faSThomas Garnier 22720483e1faSThomas Garnier The order of allocations remains unchanged. Entropy is generated in 22730483e1faSThomas Garnier the same way as RANDOMIZE_BASE. Current implementation in the optimal 22740483e1faSThomas Garnier configuration have in average 30,000 different possible virtual 22750483e1faSThomas Garnier addresses for each memory section. 22760483e1faSThomas Garnier 22776807c846SIngo Molnar If unsure, say Y. 22780483e1faSThomas Garnier 227990397a41SThomas Garnierconfig RANDOMIZE_MEMORY_PHYSICAL_PADDING 228090397a41SThomas Garnier hex "Physical memory mapping padding" if EXPERT 228190397a41SThomas Garnier depends on RANDOMIZE_MEMORY 228290397a41SThomas Garnier default "0xa" if MEMORY_HOTPLUG 228390397a41SThomas Garnier default "0x0" 228490397a41SThomas Garnier range 0x1 0x40 if MEMORY_HOTPLUG 228590397a41SThomas Garnier range 0x0 0x40 2286a7f7f624SMasahiro Yamada help 228790397a41SThomas Garnier Define the padding in terabytes added to the existing physical 228890397a41SThomas Garnier memory size during kernel memory randomization. It is useful 228990397a41SThomas Garnier for memory hotplug support but reduces the entropy available for 229090397a41SThomas Garnier address randomization. 229190397a41SThomas Garnier 229290397a41SThomas Garnier If unsure, leave at the default value. 229390397a41SThomas Garnier 22946449dcb0SKirill A. Shutemovconfig ADDRESS_MASKING 22956449dcb0SKirill A. Shutemov bool "Linear Address Masking support" 22966449dcb0SKirill A. Shutemov depends on X86_64 22976449dcb0SKirill A. Shutemov help 22986449dcb0SKirill A. Shutemov Linear Address Masking (LAM) modifies the checking that is applied 22996449dcb0SKirill A. Shutemov to 64-bit linear addresses, allowing software to use of the 23006449dcb0SKirill A. Shutemov untranslated address bits for metadata. 23016449dcb0SKirill A. Shutemov 23026449dcb0SKirill A. Shutemov The capability can be used for efficient address sanitizers (ASAN) 23036449dcb0SKirill A. Shutemov implementation and for optimizations in JITs. 23046449dcb0SKirill A. Shutemov 2305506f1d07SSam Ravnborgconfig HOTPLUG_CPU 2306bebd024eSThomas Gleixner def_bool y 230740b31360SStephen Rothwell depends on SMP 2308506f1d07SSam Ravnborg 230980aa1dffSFenghua Yuconfig BOOTPARAM_HOTPLUG_CPU0 231080aa1dffSFenghua Yu bool "Set default setting of cpu0_hotpluggable" 23112c922cd0SKees Cook depends on HOTPLUG_CPU 2312a7f7f624SMasahiro Yamada help 231380aa1dffSFenghua Yu Set whether default state of cpu0_hotpluggable is on or off. 231480aa1dffSFenghua Yu 231580aa1dffSFenghua Yu Say Y here to enable CPU0 hotplug by default. If this switch 231680aa1dffSFenghua Yu is turned on, there is no need to give cpu0_hotplug kernel 231780aa1dffSFenghua Yu parameter and the CPU0 hotplug feature is enabled by default. 231880aa1dffSFenghua Yu 231980aa1dffSFenghua Yu Please note: there are two known CPU0 dependencies if you want 232080aa1dffSFenghua Yu to enable the CPU0 hotplug feature either by this switch or by 232180aa1dffSFenghua Yu cpu0_hotplug kernel parameter. 232280aa1dffSFenghua Yu 232380aa1dffSFenghua Yu First, resume from hibernate or suspend always starts from CPU0. 232480aa1dffSFenghua Yu So hibernate and suspend are prevented if CPU0 is offline. 232580aa1dffSFenghua Yu 232680aa1dffSFenghua Yu Second dependency is PIC interrupts always go to CPU0. CPU0 can not 232780aa1dffSFenghua Yu offline if any interrupt can not migrate out of CPU0. There may 232880aa1dffSFenghua Yu be other CPU0 dependencies. 232980aa1dffSFenghua Yu 233080aa1dffSFenghua Yu Please make sure the dependencies are under your control before 233180aa1dffSFenghua Yu you enable this feature. 233280aa1dffSFenghua Yu 233380aa1dffSFenghua Yu Say N if you don't want to enable CPU0 hotplug feature by default. 233480aa1dffSFenghua Yu You still can enable the CPU0 hotplug feature at boot by kernel 233580aa1dffSFenghua Yu parameter cpu0_hotplug. 233680aa1dffSFenghua Yu 2337a71c8bc5SFenghua Yuconfig DEBUG_HOTPLUG_CPU0 2338a71c8bc5SFenghua Yu def_bool n 2339a71c8bc5SFenghua Yu prompt "Debug CPU0 hotplug" 23402c922cd0SKees Cook depends on HOTPLUG_CPU 2341a7f7f624SMasahiro Yamada help 2342a71c8bc5SFenghua Yu Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2343a71c8bc5SFenghua Yu soon as possible and boots up userspace with CPU0 offlined. User 2344a71c8bc5SFenghua Yu can online CPU0 back after boot time. 2345a71c8bc5SFenghua Yu 2346a71c8bc5SFenghua Yu To debug CPU0 hotplug, you need to enable CPU0 offline/online 2347a71c8bc5SFenghua Yu feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2348a71c8bc5SFenghua Yu compilation or giving cpu0_hotplug kernel parameter at boot. 2349a71c8bc5SFenghua Yu 2350a71c8bc5SFenghua Yu If unsure, say N. 2351a71c8bc5SFenghua Yu 2352506f1d07SSam Ravnborgconfig COMPAT_VDSO 2353b0b49f26SAndy Lutomirski def_bool n 2354b0b49f26SAndy Lutomirski prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2355953fee1dSIngo Molnar depends on COMPAT_32 2356a7f7f624SMasahiro Yamada help 2357b0b49f26SAndy Lutomirski Certain buggy versions of glibc will crash if they are 2358b0b49f26SAndy Lutomirski presented with a 32-bit vDSO that is not mapped at the address 2359b0b49f26SAndy Lutomirski indicated in its segment table. 2360e84446deSRandy Dunlap 2361b0b49f26SAndy Lutomirski The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2362b0b49f26SAndy Lutomirski and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2363b0b49f26SAndy Lutomirski 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2364b0b49f26SAndy Lutomirski the only released version with the bug, but OpenSUSE 9 2365b0b49f26SAndy Lutomirski contains a buggy "glibc 2.3.2". 2366506f1d07SSam Ravnborg 2367b0b49f26SAndy Lutomirski The symptom of the bug is that everything crashes on startup, saying: 2368b0b49f26SAndy Lutomirski dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2369b0b49f26SAndy Lutomirski 2370b0b49f26SAndy Lutomirski Saying Y here changes the default value of the vdso32 boot 2371b0b49f26SAndy Lutomirski option from 1 to 0, which turns off the 32-bit vDSO entirely. 2372b0b49f26SAndy Lutomirski This works around the glibc bug but hurts performance. 2373b0b49f26SAndy Lutomirski 2374b0b49f26SAndy Lutomirski If unsure, say N: if you are compiling your own kernel, you 2375b0b49f26SAndy Lutomirski are unlikely to be using a buggy version of glibc. 2376506f1d07SSam Ravnborg 23773dc33bd3SKees Cookchoice 23783dc33bd3SKees Cook prompt "vsyscall table for legacy applications" 23793dc33bd3SKees Cook depends on X86_64 2380625b7b7fSAndy Lutomirski default LEGACY_VSYSCALL_XONLY 23813dc33bd3SKees Cook help 23823dc33bd3SKees Cook Legacy user code that does not know how to find the vDSO expects 23833dc33bd3SKees Cook to be able to issue three syscalls by calling fixed addresses in 23843dc33bd3SKees Cook kernel space. Since this location is not randomized with ASLR, 23853dc33bd3SKees Cook it can be used to assist security vulnerability exploitation. 23863dc33bd3SKees Cook 23873dc33bd3SKees Cook This setting can be changed at boot time via the kernel command 2388bf00745eSAndy Lutomirski line parameter vsyscall=[emulate|xonly|none]. Emulate mode 2389bf00745eSAndy Lutomirski is deprecated and can only be enabled using the kernel command 2390bf00745eSAndy Lutomirski line. 23913dc33bd3SKees Cook 23923dc33bd3SKees Cook On a system with recent enough glibc (2.14 or newer) and no 23933dc33bd3SKees Cook static binaries, you can say None without a performance penalty 23943dc33bd3SKees Cook to improve security. 23953dc33bd3SKees Cook 2396bd49e16eSAndy Lutomirski If unsure, select "Emulate execution only". 23973dc33bd3SKees Cook 2398bd49e16eSAndy Lutomirski config LEGACY_VSYSCALL_XONLY 2399bd49e16eSAndy Lutomirski bool "Emulate execution only" 2400bd49e16eSAndy Lutomirski help 2401bd49e16eSAndy Lutomirski The kernel traps and emulates calls into the fixed vsyscall 2402bd49e16eSAndy Lutomirski address mapping and does not allow reads. This 2403bd49e16eSAndy Lutomirski configuration is recommended when userspace might use the 2404bd49e16eSAndy Lutomirski legacy vsyscall area but support for legacy binary 2405bd49e16eSAndy Lutomirski instrumentation of legacy code is not needed. It mitigates 2406bd49e16eSAndy Lutomirski certain uses of the vsyscall area as an ASLR-bypassing 2407bd49e16eSAndy Lutomirski buffer. 24083dc33bd3SKees Cook 24093dc33bd3SKees Cook config LEGACY_VSYSCALL_NONE 24103dc33bd3SKees Cook bool "None" 24113dc33bd3SKees Cook help 24123dc33bd3SKees Cook There will be no vsyscall mapping at all. This will 24133dc33bd3SKees Cook eliminate any risk of ASLR bypass due to the vsyscall 24143dc33bd3SKees Cook fixed address mapping. Attempts to use the vsyscalls 24153dc33bd3SKees Cook will be reported to dmesg, so that either old or 24163dc33bd3SKees Cook malicious userspace programs can be identified. 24173dc33bd3SKees Cook 24183dc33bd3SKees Cookendchoice 24193dc33bd3SKees Cook 2420516cbf37STim Birdconfig CMDLINE_BOOL 2421516cbf37STim Bird bool "Built-in kernel command line" 2422a7f7f624SMasahiro Yamada help 2423516cbf37STim Bird Allow for specifying boot arguments to the kernel at 2424516cbf37STim Bird build time. On some systems (e.g. embedded ones), it is 2425516cbf37STim Bird necessary or convenient to provide some or all of the 2426516cbf37STim Bird kernel boot arguments with the kernel itself (that is, 2427516cbf37STim Bird to not rely on the boot loader to provide them.) 2428516cbf37STim Bird 2429516cbf37STim Bird To compile command line arguments into the kernel, 2430516cbf37STim Bird set this option to 'Y', then fill in the 243169711ca1SSébastien Hinderer boot arguments in CONFIG_CMDLINE. 2432516cbf37STim Bird 2433516cbf37STim Bird Systems with fully functional boot loaders (i.e. non-embedded) 2434516cbf37STim Bird should leave this option set to 'N'. 2435516cbf37STim Bird 2436516cbf37STim Birdconfig CMDLINE 2437516cbf37STim Bird string "Built-in kernel command string" 2438516cbf37STim Bird depends on CMDLINE_BOOL 2439516cbf37STim Bird default "" 2440a7f7f624SMasahiro Yamada help 2441516cbf37STim Bird Enter arguments here that should be compiled into the kernel 2442516cbf37STim Bird image and used at boot time. If the boot loader provides a 2443516cbf37STim Bird command line at boot time, it is appended to this string to 2444516cbf37STim Bird form the full kernel command line, when the system boots. 2445516cbf37STim Bird 2446516cbf37STim Bird However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2447516cbf37STim Bird change this behavior. 2448516cbf37STim Bird 2449516cbf37STim Bird In most cases, the command line (whether built-in or provided 2450516cbf37STim Bird by the boot loader) should specify the device for the root 2451516cbf37STim Bird file system. 2452516cbf37STim Bird 2453516cbf37STim Birdconfig CMDLINE_OVERRIDE 2454516cbf37STim Bird bool "Built-in command line overrides boot loader arguments" 2455645e6466SAnders Roxell depends on CMDLINE_BOOL && CMDLINE != "" 2456a7f7f624SMasahiro Yamada help 2457516cbf37STim Bird Set this option to 'Y' to have the kernel ignore the boot loader 2458516cbf37STim Bird command line, and use ONLY the built-in command line. 2459516cbf37STim Bird 2460516cbf37STim Bird This is used to work around broken boot loaders. This should 2461516cbf37STim Bird be set to 'N' under normal conditions. 2462516cbf37STim Bird 2463a5b9e5a2SAndy Lutomirskiconfig MODIFY_LDT_SYSCALL 2464a5b9e5a2SAndy Lutomirski bool "Enable the LDT (local descriptor table)" if EXPERT 2465a5b9e5a2SAndy Lutomirski default y 2466a7f7f624SMasahiro Yamada help 2467a5b9e5a2SAndy Lutomirski Linux can allow user programs to install a per-process x86 2468a5b9e5a2SAndy Lutomirski Local Descriptor Table (LDT) using the modify_ldt(2) system 2469a5b9e5a2SAndy Lutomirski call. This is required to run 16-bit or segmented code such as 2470a5b9e5a2SAndy Lutomirski DOSEMU or some Wine programs. It is also used by some very old 2471a5b9e5a2SAndy Lutomirski threading libraries. 2472a5b9e5a2SAndy Lutomirski 2473a5b9e5a2SAndy Lutomirski Enabling this feature adds a small amount of overhead to 2474a5b9e5a2SAndy Lutomirski context switches and increases the low-level kernel attack 2475a5b9e5a2SAndy Lutomirski surface. Disabling it removes the modify_ldt(2) system call. 2476a5b9e5a2SAndy Lutomirski 2477a5b9e5a2SAndy Lutomirski Saying 'N' here may make sense for embedded or server kernels. 2478a5b9e5a2SAndy Lutomirski 24793aac3ebeSThomas Gleixnerconfig STRICT_SIGALTSTACK_SIZE 24803aac3ebeSThomas Gleixner bool "Enforce strict size checking for sigaltstack" 24813aac3ebeSThomas Gleixner depends on DYNAMIC_SIGFRAME 24823aac3ebeSThomas Gleixner help 24833aac3ebeSThomas Gleixner For historical reasons MINSIGSTKSZ is a constant which became 24843aac3ebeSThomas Gleixner already too small with AVX512 support. Add a mechanism to 24853aac3ebeSThomas Gleixner enforce strict checking of the sigaltstack size against the 24863aac3ebeSThomas Gleixner real size of the FPU frame. This option enables the check 24873aac3ebeSThomas Gleixner by default. It can also be controlled via the kernel command 24883aac3ebeSThomas Gleixner line option 'strict_sas_size' independent of this config 24893aac3ebeSThomas Gleixner switch. Enabling it might break existing applications which 24903aac3ebeSThomas Gleixner allocate a too small sigaltstack but 'work' because they 24913aac3ebeSThomas Gleixner never get a signal delivered. 24923aac3ebeSThomas Gleixner 24933aac3ebeSThomas Gleixner Say 'N' unless you want to really enforce this check. 24943aac3ebeSThomas Gleixner 2495b700e7f0SSeth Jenningssource "kernel/livepatch/Kconfig" 2496b700e7f0SSeth Jennings 2497506f1d07SSam Ravnborgendmenu 2498506f1d07SSam Ravnborg 2499f43b9876SPeter Zijlstraconfig CC_HAS_SLS 2500f43b9876SPeter Zijlstra def_bool $(cc-option,-mharden-sls=all) 2501f43b9876SPeter Zijlstra 2502f43b9876SPeter Zijlstraconfig CC_HAS_RETURN_THUNK 2503f43b9876SPeter Zijlstra def_bool $(cc-option,-mfunction-return=thunk-extern) 2504f43b9876SPeter Zijlstra 2505bea75b33SThomas Gleixnerconfig CC_HAS_ENTRY_PADDING 2506bea75b33SThomas Gleixner def_bool $(cc-option,-fpatchable-function-entry=16,16) 2507bea75b33SThomas Gleixner 2508bea75b33SThomas Gleixnerconfig FUNCTION_PADDING_CFI 2509bea75b33SThomas Gleixner int 2510bea75b33SThomas Gleixner default 59 if FUNCTION_ALIGNMENT_64B 2511bea75b33SThomas Gleixner default 27 if FUNCTION_ALIGNMENT_32B 2512bea75b33SThomas Gleixner default 11 if FUNCTION_ALIGNMENT_16B 2513bea75b33SThomas Gleixner default 3 if FUNCTION_ALIGNMENT_8B 2514bea75b33SThomas Gleixner default 0 2515bea75b33SThomas Gleixner 2516bea75b33SThomas Gleixner# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG 2517bea75b33SThomas Gleixner# except Kconfig can't do arithmetic :/ 2518bea75b33SThomas Gleixnerconfig FUNCTION_PADDING_BYTES 2519bea75b33SThomas Gleixner int 2520bea75b33SThomas Gleixner default FUNCTION_PADDING_CFI if CFI_CLANG 2521bea75b33SThomas Gleixner default FUNCTION_ALIGNMENT 2522bea75b33SThomas Gleixner 2523931ab636SPeter Zijlstraconfig CALL_PADDING 2524931ab636SPeter Zijlstra def_bool n 2525931ab636SPeter Zijlstra depends on CC_HAS_ENTRY_PADDING && OBJTOOL 2526931ab636SPeter Zijlstra select FUNCTION_ALIGNMENT_16B 2527931ab636SPeter Zijlstra 2528931ab636SPeter Zijlstraconfig FINEIBT 2529931ab636SPeter Zijlstra def_bool y 2530931ab636SPeter Zijlstra depends on X86_KERNEL_IBT && CFI_CLANG && RETPOLINE 2531931ab636SPeter Zijlstra select CALL_PADDING 2532931ab636SPeter Zijlstra 25338f7c0d8bSThomas Gleixnerconfig HAVE_CALL_THUNKS 25348f7c0d8bSThomas Gleixner def_bool y 2535bea75b33SThomas Gleixner depends on CC_HAS_ENTRY_PADDING && RETHUNK && OBJTOOL 25368f7c0d8bSThomas Gleixner 25378f7c0d8bSThomas Gleixnerconfig CALL_THUNKS 25388f7c0d8bSThomas Gleixner def_bool n 2539931ab636SPeter Zijlstra select CALL_PADDING 25408f7c0d8bSThomas Gleixner 2541b341b20dSPeter Zijlstraconfig PREFIX_SYMBOLS 2542b341b20dSPeter Zijlstra def_bool y 2543931ab636SPeter Zijlstra depends on CALL_PADDING && !CFI_CLANG 2544b341b20dSPeter Zijlstra 2545f43b9876SPeter Zijlstramenuconfig SPECULATION_MITIGATIONS 2546f43b9876SPeter Zijlstra bool "Mitigations for speculative execution vulnerabilities" 2547f43b9876SPeter Zijlstra default y 2548f43b9876SPeter Zijlstra help 2549f43b9876SPeter Zijlstra Say Y here to enable options which enable mitigations for 2550f43b9876SPeter Zijlstra speculative execution hardware vulnerabilities. 2551f43b9876SPeter Zijlstra 2552f43b9876SPeter Zijlstra If you say N, all mitigations will be disabled. You really 2553f43b9876SPeter Zijlstra should know what you are doing to say so. 2554f43b9876SPeter Zijlstra 2555f43b9876SPeter Zijlstraif SPECULATION_MITIGATIONS 2556f43b9876SPeter Zijlstra 2557f43b9876SPeter Zijlstraconfig PAGE_TABLE_ISOLATION 2558f43b9876SPeter Zijlstra bool "Remove the kernel mapping in user mode" 2559f43b9876SPeter Zijlstra default y 2560f43b9876SPeter Zijlstra depends on (X86_64 || X86_PAE) 2561f43b9876SPeter Zijlstra help 2562f43b9876SPeter Zijlstra This feature reduces the number of hardware side channels by 2563f43b9876SPeter Zijlstra ensuring that the majority of kernel addresses are not mapped 2564f43b9876SPeter Zijlstra into userspace. 2565f43b9876SPeter Zijlstra 2566ff61f079SJonathan Corbet See Documentation/arch/x86/pti.rst for more details. 2567f43b9876SPeter Zijlstra 2568f43b9876SPeter Zijlstraconfig RETPOLINE 2569f43b9876SPeter Zijlstra bool "Avoid speculative indirect branches in kernel" 2570f43b9876SPeter Zijlstra select OBJTOOL if HAVE_OBJTOOL 2571f43b9876SPeter Zijlstra default y 2572f43b9876SPeter Zijlstra help 2573f43b9876SPeter Zijlstra Compile kernel with the retpoline compiler options to guard against 2574f43b9876SPeter Zijlstra kernel-to-user data leaks by avoiding speculative indirect 2575f43b9876SPeter Zijlstra branches. Requires a compiler with -mindirect-branch=thunk-extern 2576f43b9876SPeter Zijlstra support for full protection. The kernel may run slower. 2577f43b9876SPeter Zijlstra 2578f43b9876SPeter Zijlstraconfig RETHUNK 2579f43b9876SPeter Zijlstra bool "Enable return-thunks" 2580f43b9876SPeter Zijlstra depends on RETPOLINE && CC_HAS_RETURN_THUNK 2581f43b9876SPeter Zijlstra select OBJTOOL if HAVE_OBJTOOL 2582b648ab48SBen Hutchings default y if X86_64 2583f43b9876SPeter Zijlstra help 2584f43b9876SPeter Zijlstra Compile the kernel with the return-thunks compiler option to guard 2585f43b9876SPeter Zijlstra against kernel-to-user data leaks by avoiding return speculation. 2586f43b9876SPeter Zijlstra Requires a compiler with -mfunction-return=thunk-extern 2587f43b9876SPeter Zijlstra support for full protection. The kernel may run slower. 2588f43b9876SPeter Zijlstra 2589f43b9876SPeter Zijlstraconfig CPU_UNRET_ENTRY 2590f43b9876SPeter Zijlstra bool "Enable UNRET on kernel entry" 2591b648ab48SBen Hutchings depends on CPU_SUP_AMD && RETHUNK && X86_64 2592f43b9876SPeter Zijlstra default y 2593f43b9876SPeter Zijlstra help 2594f43b9876SPeter Zijlstra Compile the kernel with support for the retbleed=unret mitigation. 2595f43b9876SPeter Zijlstra 259680e4c1cdSThomas Gleixnerconfig CALL_DEPTH_TRACKING 259780e4c1cdSThomas Gleixner bool "Mitigate RSB underflow with call depth tracking" 259880e4c1cdSThomas Gleixner depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS 259980e4c1cdSThomas Gleixner select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 260080e4c1cdSThomas Gleixner select CALL_THUNKS 260180e4c1cdSThomas Gleixner default y 260280e4c1cdSThomas Gleixner help 260380e4c1cdSThomas Gleixner Compile the kernel with call depth tracking to mitigate the Intel 260480e4c1cdSThomas Gleixner SKL Return-Speculation-Buffer (RSB) underflow issue. The 260580e4c1cdSThomas Gleixner mitigation is off by default and needs to be enabled on the 260680e4c1cdSThomas Gleixner kernel command line via the retbleed=stuff option. For 260780e4c1cdSThomas Gleixner non-affected systems the overhead of this option is marginal as 260880e4c1cdSThomas Gleixner the call depth tracking is using run-time generated call thunks 260980e4c1cdSThomas Gleixner in a compiler generated padding area and call patching. This 261080e4c1cdSThomas Gleixner increases text size by ~5%. For non affected systems this space 261180e4c1cdSThomas Gleixner is unused. On affected SKL systems this results in a significant 261280e4c1cdSThomas Gleixner performance gain over the IBRS mitigation. 261380e4c1cdSThomas Gleixner 2614e81dc127SThomas Gleixnerconfig CALL_THUNKS_DEBUG 2615e81dc127SThomas Gleixner bool "Enable call thunks and call depth tracking debugging" 2616e81dc127SThomas Gleixner depends on CALL_DEPTH_TRACKING 2617e81dc127SThomas Gleixner select FUNCTION_ALIGNMENT_32B 2618e81dc127SThomas Gleixner default n 2619e81dc127SThomas Gleixner help 2620e81dc127SThomas Gleixner Enable call/ret counters for imbalance detection and build in 2621e81dc127SThomas Gleixner a noisy dmesg about callthunks generation and call patching for 2622e81dc127SThomas Gleixner trouble shooting. The debug prints need to be enabled on the 2623e81dc127SThomas Gleixner kernel command line with 'debug-callthunks'. 262454628de6SRandy Dunlap Only enable this when you are debugging call thunks as this 262554628de6SRandy Dunlap creates a noticeable runtime overhead. If unsure say N. 262680e4c1cdSThomas Gleixner 2627f43b9876SPeter Zijlstraconfig CPU_IBPB_ENTRY 2628f43b9876SPeter Zijlstra bool "Enable IBPB on kernel entry" 2629b648ab48SBen Hutchings depends on CPU_SUP_AMD && X86_64 2630f43b9876SPeter Zijlstra default y 2631f43b9876SPeter Zijlstra help 2632f43b9876SPeter Zijlstra Compile the kernel with support for the retbleed=ibpb mitigation. 2633f43b9876SPeter Zijlstra 2634f43b9876SPeter Zijlstraconfig CPU_IBRS_ENTRY 2635f43b9876SPeter Zijlstra bool "Enable IBRS on kernel entry" 2636b648ab48SBen Hutchings depends on CPU_SUP_INTEL && X86_64 2637f43b9876SPeter Zijlstra default y 2638f43b9876SPeter Zijlstra help 2639f43b9876SPeter Zijlstra Compile the kernel with support for the spectre_v2=ibrs mitigation. 2640f43b9876SPeter Zijlstra This mitigates both spectre_v2 and retbleed at great cost to 2641f43b9876SPeter Zijlstra performance. 2642f43b9876SPeter Zijlstra 2643f43b9876SPeter Zijlstraconfig SLS 2644f43b9876SPeter Zijlstra bool "Mitigate Straight-Line-Speculation" 2645f43b9876SPeter Zijlstra depends on CC_HAS_SLS && X86_64 2646f43b9876SPeter Zijlstra select OBJTOOL if HAVE_OBJTOOL 2647f43b9876SPeter Zijlstra default n 2648f43b9876SPeter Zijlstra help 2649f43b9876SPeter Zijlstra Compile the kernel with straight-line-speculation options to guard 2650f43b9876SPeter Zijlstra against straight line speculation. The kernel image might be slightly 2651f43b9876SPeter Zijlstra larger. 2652f43b9876SPeter Zijlstra 2653f43b9876SPeter Zijlstraendif 2654f43b9876SPeter Zijlstra 26553072e413SMichal Hockoconfig ARCH_HAS_ADD_PAGES 26563072e413SMichal Hocko def_bool y 26575c11f00bSDavid Hildenbrand depends on ARCH_ENABLE_MEMORY_HOTPLUG 26583072e413SMichal Hocko 2659f91ef222SOscar Salvadorconfig ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 2660f91ef222SOscar Salvador def_bool y 2661f91ef222SOscar Salvador 2662da85f865SBjorn Helgaasmenu "Power management and ACPI options" 2663e279b6c1SSam Ravnborg 2664e279b6c1SSam Ravnborgconfig ARCH_HIBERNATION_HEADER 26653c2362e6SHarvey Harrison def_bool y 266644556530SZhimin Gu depends on HIBERNATION 2667e279b6c1SSam Ravnborg 2668e279b6c1SSam Ravnborgsource "kernel/power/Kconfig" 2669e279b6c1SSam Ravnborg 2670e279b6c1SSam Ravnborgsource "drivers/acpi/Kconfig" 2671e279b6c1SSam Ravnborg 2672a6b68076SAndi Kleenconfig X86_APM_BOOT 26736fc108a0SJan Beulich def_bool y 2674282e5aabSPaul Bolle depends on APM 2675a6b68076SAndi Kleen 2676e279b6c1SSam Ravnborgmenuconfig APM 2677e279b6c1SSam Ravnborg tristate "APM (Advanced Power Management) BIOS support" 2678efefa6f6SIngo Molnar depends on X86_32 && PM_SLEEP 2679a7f7f624SMasahiro Yamada help 2680e279b6c1SSam Ravnborg APM is a BIOS specification for saving power using several different 2681e279b6c1SSam Ravnborg techniques. This is mostly useful for battery powered laptops with 2682e279b6c1SSam Ravnborg APM compliant BIOSes. If you say Y here, the system time will be 2683e279b6c1SSam Ravnborg reset after a RESUME operation, the /proc/apm device will provide 2684e279b6c1SSam Ravnborg battery status information, and user-space programs will receive 2685e279b6c1SSam Ravnborg notification of APM "events" (e.g. battery status change). 2686e279b6c1SSam Ravnborg 2687e279b6c1SSam Ravnborg If you select "Y" here, you can disable actual use of the APM 2688e279b6c1SSam Ravnborg BIOS by passing the "apm=off" option to the kernel at boot time. 2689e279b6c1SSam Ravnborg 2690e279b6c1SSam Ravnborg Note that the APM support is almost completely disabled for 2691e279b6c1SSam Ravnborg machines with more than one CPU. 2692e279b6c1SSam Ravnborg 2693e279b6c1SSam Ravnborg In order to use APM, you will need supporting software. For location 2694151f4e2bSMauro Carvalho Chehab and more information, read <file:Documentation/power/apm-acpi.rst> 26952dc98fd3SMichael Witten and the Battery Powered Linux mini-HOWTO, available from 2696e279b6c1SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 2697e279b6c1SSam Ravnborg 2698e279b6c1SSam Ravnborg This driver does not spin down disk drives (see the hdparm(8) 2699e279b6c1SSam Ravnborg manpage ("man 8 hdparm") for that), and it doesn't turn off 2700e279b6c1SSam Ravnborg VESA-compliant "green" monitors. 2701e279b6c1SSam Ravnborg 2702e279b6c1SSam Ravnborg This driver does not support the TI 4000M TravelMate and the ACER 2703e279b6c1SSam Ravnborg 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2704e279b6c1SSam Ravnborg desktop machines also don't have compliant BIOSes, and this driver 2705e279b6c1SSam Ravnborg may cause those machines to panic during the boot phase. 2706e279b6c1SSam Ravnborg 2707e279b6c1SSam Ravnborg Generally, if you don't have a battery in your machine, there isn't 2708e279b6c1SSam Ravnborg much point in using this driver and you should say N. If you get 2709e279b6c1SSam Ravnborg random kernel OOPSes or reboots that don't seem to be related to 2710e279b6c1SSam Ravnborg anything, try disabling/enabling this option (or disabling/enabling 2711e279b6c1SSam Ravnborg APM in your BIOS). 2712e279b6c1SSam Ravnborg 2713e279b6c1SSam Ravnborg Some other things you should try when experiencing seemingly random, 2714e279b6c1SSam Ravnborg "weird" problems: 2715e279b6c1SSam Ravnborg 2716e279b6c1SSam Ravnborg 1) make sure that you have enough swap space and that it is 2717e279b6c1SSam Ravnborg enabled. 27187987448fSStephen Kitt 2) pass the "idle=poll" option to the kernel 2719e279b6c1SSam Ravnborg 3) switch on floating point emulation in the kernel and pass 2720e279b6c1SSam Ravnborg the "no387" option to the kernel 2721e279b6c1SSam Ravnborg 4) pass the "floppy=nodma" option to the kernel 2722e279b6c1SSam Ravnborg 5) pass the "mem=4M" option to the kernel (thereby disabling 2723e279b6c1SSam Ravnborg all but the first 4 MB of RAM) 2724e279b6c1SSam Ravnborg 6) make sure that the CPU is not over clocked. 2725e279b6c1SSam Ravnborg 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2726e279b6c1SSam Ravnborg 8) disable the cache from your BIOS settings 2727e279b6c1SSam Ravnborg 9) install a fan for the video card or exchange video RAM 2728e279b6c1SSam Ravnborg 10) install a better fan for the CPU 2729e279b6c1SSam Ravnborg 11) exchange RAM chips 2730e279b6c1SSam Ravnborg 12) exchange the motherboard. 2731e279b6c1SSam Ravnborg 2732e279b6c1SSam Ravnborg To compile this driver as a module, choose M here: the 2733e279b6c1SSam Ravnborg module will be called apm. 2734e279b6c1SSam Ravnborg 2735e279b6c1SSam Ravnborgif APM 2736e279b6c1SSam Ravnborg 2737e279b6c1SSam Ravnborgconfig APM_IGNORE_USER_SUSPEND 2738e279b6c1SSam Ravnborg bool "Ignore USER SUSPEND" 2739a7f7f624SMasahiro Yamada help 2740e279b6c1SSam Ravnborg This option will ignore USER SUSPEND requests. On machines with a 2741e279b6c1SSam Ravnborg compliant APM BIOS, you want to say N. However, on the NEC Versa M 2742e279b6c1SSam Ravnborg series notebooks, it is necessary to say Y because of a BIOS bug. 2743e279b6c1SSam Ravnborg 2744e279b6c1SSam Ravnborgconfig APM_DO_ENABLE 2745e279b6c1SSam Ravnborg bool "Enable PM at boot time" 2746a7f7f624SMasahiro Yamada help 2747e279b6c1SSam Ravnborg Enable APM features at boot time. From page 36 of the APM BIOS 2748e279b6c1SSam Ravnborg specification: "When disabled, the APM BIOS does not automatically 2749e279b6c1SSam Ravnborg power manage devices, enter the Standby State, enter the Suspend 2750e279b6c1SSam Ravnborg State, or take power saving steps in response to CPU Idle calls." 2751e279b6c1SSam Ravnborg This driver will make CPU Idle calls when Linux is idle (unless this 2752e279b6c1SSam Ravnborg feature is turned off -- see "Do CPU IDLE calls", below). This 2753e279b6c1SSam Ravnborg should always save battery power, but more complicated APM features 2754e279b6c1SSam Ravnborg will be dependent on your BIOS implementation. You may need to turn 2755e279b6c1SSam Ravnborg this option off if your computer hangs at boot time when using APM 2756e279b6c1SSam Ravnborg support, or if it beeps continuously instead of suspending. Turn 2757e279b6c1SSam Ravnborg this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2758e279b6c1SSam Ravnborg T400CDT. This is off by default since most machines do fine without 2759e279b6c1SSam Ravnborg this feature. 2760e279b6c1SSam Ravnborg 2761e279b6c1SSam Ravnborgconfig APM_CPU_IDLE 2762dd8af076SLen Brown depends on CPU_IDLE 2763e279b6c1SSam Ravnborg bool "Make CPU Idle calls when idle" 2764a7f7f624SMasahiro Yamada help 2765e279b6c1SSam Ravnborg Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2766e279b6c1SSam Ravnborg On some machines, this can activate improved power savings, such as 2767e279b6c1SSam Ravnborg a slowed CPU clock rate, when the machine is idle. These idle calls 2768e279b6c1SSam Ravnborg are made after the idle loop has run for some length of time (e.g., 2769e279b6c1SSam Ravnborg 333 mS). On some machines, this will cause a hang at boot time or 2770e279b6c1SSam Ravnborg whenever the CPU becomes idle. (On machines with more than one CPU, 2771e279b6c1SSam Ravnborg this option does nothing.) 2772e279b6c1SSam Ravnborg 2773e279b6c1SSam Ravnborgconfig APM_DISPLAY_BLANK 2774e279b6c1SSam Ravnborg bool "Enable console blanking using APM" 2775a7f7f624SMasahiro Yamada help 2776e279b6c1SSam Ravnborg Enable console blanking using the APM. Some laptops can use this to 2777e279b6c1SSam Ravnborg turn off the LCD backlight when the screen blanker of the Linux 2778e279b6c1SSam Ravnborg virtual console blanks the screen. Note that this is only used by 2779e279b6c1SSam Ravnborg the virtual console screen blanker, and won't turn off the backlight 2780e279b6c1SSam Ravnborg when using the X Window system. This also doesn't have anything to 2781e279b6c1SSam Ravnborg do with your VESA-compliant power-saving monitor. Further, this 2782e279b6c1SSam Ravnborg option doesn't work for all laptops -- it might not turn off your 2783e279b6c1SSam Ravnborg backlight at all, or it might print a lot of errors to the console, 2784e279b6c1SSam Ravnborg especially if you are using gpm. 2785e279b6c1SSam Ravnborg 2786e279b6c1SSam Ravnborgconfig APM_ALLOW_INTS 2787e279b6c1SSam Ravnborg bool "Allow interrupts during APM BIOS calls" 2788a7f7f624SMasahiro Yamada help 2789e279b6c1SSam Ravnborg Normally we disable external interrupts while we are making calls to 2790e279b6c1SSam Ravnborg the APM BIOS as a measure to lessen the effects of a badly behaving 2791e279b6c1SSam Ravnborg BIOS implementation. The BIOS should reenable interrupts if it 2792e279b6c1SSam Ravnborg needs to. Unfortunately, some BIOSes do not -- especially those in 2793e279b6c1SSam Ravnborg many of the newer IBM Thinkpads. If you experience hangs when you 2794e279b6c1SSam Ravnborg suspend, try setting this to Y. Otherwise, say N. 2795e279b6c1SSam Ravnborg 2796e279b6c1SSam Ravnborgendif # APM 2797e279b6c1SSam Ravnborg 2798bb0a56ecSDave Jonessource "drivers/cpufreq/Kconfig" 2799e279b6c1SSam Ravnborg 2800e279b6c1SSam Ravnborgsource "drivers/cpuidle/Kconfig" 2801e279b6c1SSam Ravnborg 280227471fdbSAndy Henroidsource "drivers/idle/Kconfig" 280327471fdbSAndy Henroid 2804e279b6c1SSam Ravnborgendmenu 2805e279b6c1SSam Ravnborg 2806e279b6c1SSam Ravnborgmenu "Bus options (PCI etc.)" 2807e279b6c1SSam Ravnborg 2808e279b6c1SSam Ravnborgchoice 2809e279b6c1SSam Ravnborg prompt "PCI access mode" 2810efefa6f6SIngo Molnar depends on X86_32 && PCI 2811e279b6c1SSam Ravnborg default PCI_GOANY 2812a7f7f624SMasahiro Yamada help 2813e279b6c1SSam Ravnborg On PCI systems, the BIOS can be used to detect the PCI devices and 2814e279b6c1SSam Ravnborg determine their configuration. However, some old PCI motherboards 2815e279b6c1SSam Ravnborg have BIOS bugs and may crash if this is done. Also, some embedded 2816e279b6c1SSam Ravnborg PCI-based systems don't have any BIOS at all. Linux can also try to 2817e279b6c1SSam Ravnborg detect the PCI hardware directly without using the BIOS. 2818e279b6c1SSam Ravnborg 2819e279b6c1SSam Ravnborg With this option, you can specify how Linux should detect the 2820e279b6c1SSam Ravnborg PCI devices. If you choose "BIOS", the BIOS will be used, 2821e279b6c1SSam Ravnborg if you choose "Direct", the BIOS won't be used, and if you 2822e279b6c1SSam Ravnborg choose "MMConfig", then PCI Express MMCONFIG will be used. 2823e279b6c1SSam Ravnborg If you choose "Any", the kernel will try MMCONFIG, then the 2824e279b6c1SSam Ravnborg direct access method and falls back to the BIOS if that doesn't 2825e279b6c1SSam Ravnborg work. If unsure, go with the default, which is "Any". 2826e279b6c1SSam Ravnborg 2827e279b6c1SSam Ravnborgconfig PCI_GOBIOS 2828e279b6c1SSam Ravnborg bool "BIOS" 2829e279b6c1SSam Ravnborg 2830e279b6c1SSam Ravnborgconfig PCI_GOMMCONFIG 2831e279b6c1SSam Ravnborg bool "MMConfig" 2832e279b6c1SSam Ravnborg 2833e279b6c1SSam Ravnborgconfig PCI_GODIRECT 2834e279b6c1SSam Ravnborg bool "Direct" 2835e279b6c1SSam Ravnborg 28363ef0e1f8SAndres Salomonconfig PCI_GOOLPC 283776fb6570SDaniel Drake bool "OLPC XO-1" 28383ef0e1f8SAndres Salomon depends on OLPC 28393ef0e1f8SAndres Salomon 28402bdd1b03SAndres Salomonconfig PCI_GOANY 28412bdd1b03SAndres Salomon bool "Any" 28422bdd1b03SAndres Salomon 2843e279b6c1SSam Ravnborgendchoice 2844e279b6c1SSam Ravnborg 2845e279b6c1SSam Ravnborgconfig PCI_BIOS 28463c2362e6SHarvey Harrison def_bool y 2847efefa6f6SIngo Molnar depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2848e279b6c1SSam Ravnborg 2849e279b6c1SSam Ravnborg# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2850e279b6c1SSam Ravnborgconfig PCI_DIRECT 28513c2362e6SHarvey Harrison def_bool y 28520aba496fSShaohua Li depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2853e279b6c1SSam Ravnborg 2854e279b6c1SSam Ravnborgconfig PCI_MMCONFIG 2855b45c9f36SJan Kiszka bool "Support mmconfig PCI config space access" if X86_64 2856b45c9f36SJan Kiszka default y 28574590d98fSAndy Shevchenko depends on PCI && (ACPI || JAILHOUSE_GUEST) 2858b45c9f36SJan Kiszka depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2859e279b6c1SSam Ravnborg 28603ef0e1f8SAndres Salomonconfig PCI_OLPC 28612bdd1b03SAndres Salomon def_bool y 28622bdd1b03SAndres Salomon depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 28633ef0e1f8SAndres Salomon 2864b5401a96SAlex Nixonconfig PCI_XEN 2865b5401a96SAlex Nixon def_bool y 2866b5401a96SAlex Nixon depends on PCI && XEN 2867b5401a96SAlex Nixon 28688364e1f8SJan Kiszkaconfig MMCONF_FAM10H 28698364e1f8SJan Kiszka def_bool y 28708364e1f8SJan Kiszka depends on X86_64 && PCI_MMCONFIG && ACPI 2871e279b6c1SSam Ravnborg 28723f6ea84aSIra W. Snyderconfig PCI_CNB20LE_QUIRK 28736a108a14SDavid Rientjes bool "Read CNB20LE Host Bridge Windows" if EXPERT 28746ea30386SKees Cook depends on PCI 28753f6ea84aSIra W. Snyder help 28763f6ea84aSIra W. Snyder Read the PCI windows out of the CNB20LE host bridge. This allows 28773f6ea84aSIra W. Snyder PCI hotplug to work on systems with the CNB20LE chipset which do 28783f6ea84aSIra W. Snyder not have ACPI. 28793f6ea84aSIra W. Snyder 288064a5fed6SBjorn Helgaas There's no public spec for this chipset, and this functionality 288164a5fed6SBjorn Helgaas is known to be incomplete. 288264a5fed6SBjorn Helgaas 288364a5fed6SBjorn Helgaas You should say N unless you know you need this. 288464a5fed6SBjorn Helgaas 28853a495511SWilliam Breathitt Grayconfig ISA_BUS 288617a2a129SWilliam Breathitt Gray bool "ISA bus support on modern systems" if EXPERT 28873a495511SWilliam Breathitt Gray help 288817a2a129SWilliam Breathitt Gray Expose ISA bus device drivers and options available for selection and 288917a2a129SWilliam Breathitt Gray configuration. Enable this option if your target machine has an ISA 289017a2a129SWilliam Breathitt Gray bus. ISA is an older system, displaced by PCI and newer bus 289117a2a129SWilliam Breathitt Gray architectures -- if your target machine is modern, it probably does 289217a2a129SWilliam Breathitt Gray not have an ISA bus. 28933a495511SWilliam Breathitt Gray 28943a495511SWilliam Breathitt Gray If unsure, say N. 28953a495511SWilliam Breathitt Gray 28961c00f016SDavid Rientjes# x86_64 have no ISA slots, but can have ISA-style DMA. 2897e279b6c1SSam Ravnborgconfig ISA_DMA_API 28981c00f016SDavid Rientjes bool "ISA-style DMA support" if (X86_64 && EXPERT) 28991c00f016SDavid Rientjes default y 29001c00f016SDavid Rientjes help 29011c00f016SDavid Rientjes Enables ISA-style DMA support for devices requiring such controllers. 29021c00f016SDavid Rientjes If unsure, say Y. 2903e279b6c1SSam Ravnborg 290451e68d05SLinus Torvaldsif X86_32 290551e68d05SLinus Torvalds 2906e279b6c1SSam Ravnborgconfig ISA 2907e279b6c1SSam Ravnborg bool "ISA support" 2908a7f7f624SMasahiro Yamada help 2909e279b6c1SSam Ravnborg Find out whether you have ISA slots on your motherboard. ISA is the 2910e279b6c1SSam Ravnborg name of a bus system, i.e. the way the CPU talks to the other stuff 2911e279b6c1SSam Ravnborg inside your box. Other bus systems are PCI, EISA, MicroChannel 2912e279b6c1SSam Ravnborg (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2913e279b6c1SSam Ravnborg newer boards don't support it. If you have ISA, say Y, otherwise N. 2914e279b6c1SSam Ravnborg 2915e279b6c1SSam Ravnborgconfig SCx200 2916e279b6c1SSam Ravnborg tristate "NatSemi SCx200 support" 2917a7f7f624SMasahiro Yamada help 2918e279b6c1SSam Ravnborg This provides basic support for National Semiconductor's 2919e279b6c1SSam Ravnborg (now AMD's) Geode processors. The driver probes for the 2920e279b6c1SSam Ravnborg PCI-IDs of several on-chip devices, so its a good dependency 2921e279b6c1SSam Ravnborg for other scx200_* drivers. 2922e279b6c1SSam Ravnborg 2923e279b6c1SSam Ravnborg If compiled as a module, the driver is named scx200. 2924e279b6c1SSam Ravnborg 2925e279b6c1SSam Ravnborgconfig SCx200HR_TIMER 2926e279b6c1SSam Ravnborg tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2927592913ecSJohn Stultz depends on SCx200 2928e279b6c1SSam Ravnborg default y 2929a7f7f624SMasahiro Yamada help 2930e279b6c1SSam Ravnborg This driver provides a clocksource built upon the on-chip 2931e279b6c1SSam Ravnborg 27MHz high-resolution timer. Its also a workaround for 2932e279b6c1SSam Ravnborg NSC Geode SC-1100's buggy TSC, which loses time when the 2933e279b6c1SSam Ravnborg processor goes idle (as is done by the scheduler). The 2934e279b6c1SSam Ravnborg other workaround is idle=poll boot option. 2935e279b6c1SSam Ravnborg 29363ef0e1f8SAndres Salomonconfig OLPC 29373ef0e1f8SAndres Salomon bool "One Laptop Per Child support" 293854008979SThomas Gleixner depends on !X86_PAE 29393c554946SAndres Salomon select GPIOLIB 2940dc3119e7SThomas Gleixner select OF 294145bb1674SDaniel Drake select OF_PROMTREE 2942b4e51854SGrant Likely select IRQ_DOMAIN 29430c3d931bSLubomir Rintel select OLPC_EC 2944a7f7f624SMasahiro Yamada help 29453ef0e1f8SAndres Salomon Add support for detecting the unique features of the OLPC 29463ef0e1f8SAndres Salomon XO hardware. 29473ef0e1f8SAndres Salomon 2948a3128588SDaniel Drakeconfig OLPC_XO1_PM 2949a3128588SDaniel Drake bool "OLPC XO-1 Power Management" 2950fa112cf1SBorislav Petkov depends on OLPC && MFD_CS5535=y && PM_SLEEP 2951a7f7f624SMasahiro Yamada help 295297c4cb71SDaniel Drake Add support for poweroff and suspend of the OLPC XO-1 laptop. 2953bf1ebf00SDaniel Drake 2954cfee9597SDaniel Drakeconfig OLPC_XO1_RTC 2955cfee9597SDaniel Drake bool "OLPC XO-1 Real Time Clock" 2956cfee9597SDaniel Drake depends on OLPC_XO1_PM && RTC_DRV_CMOS 2957a7f7f624SMasahiro Yamada help 2958cfee9597SDaniel Drake Add support for the XO-1 real time clock, which can be used as a 2959cfee9597SDaniel Drake programmable wakeup source. 2960cfee9597SDaniel Drake 29617feda8e9SDaniel Drakeconfig OLPC_XO1_SCI 29627feda8e9SDaniel Drake bool "OLPC XO-1 SCI extras" 296392e830f2SArnd Bergmann depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2964ed8e47feSRandy Dunlap depends on INPUT=y 2965d8d01a63SDaniel Drake select POWER_SUPPLY 2966a7f7f624SMasahiro Yamada help 29677feda8e9SDaniel Drake Add support for SCI-based features of the OLPC XO-1 laptop: 29687bc74b3dSDaniel Drake - EC-driven system wakeups 29697feda8e9SDaniel Drake - Power button 29707bc74b3dSDaniel Drake - Ebook switch 29712cf2baeaSDaniel Drake - Lid switch 2972e1040ac6SDaniel Drake - AC adapter status updates 2973e1040ac6SDaniel Drake - Battery status updates 29747feda8e9SDaniel Drake 2975a0f30f59SDaniel Drakeconfig OLPC_XO15_SCI 2976a0f30f59SDaniel Drake bool "OLPC XO-1.5 SCI extras" 2977d8d01a63SDaniel Drake depends on OLPC && ACPI 2978d8d01a63SDaniel Drake select POWER_SUPPLY 2979a7f7f624SMasahiro Yamada help 2980a0f30f59SDaniel Drake Add support for SCI-based features of the OLPC XO-1.5 laptop: 2981a0f30f59SDaniel Drake - EC-driven system wakeups 2982a0f30f59SDaniel Drake - AC adapter status updates 2983a0f30f59SDaniel Drake - Battery status updates 2984e279b6c1SSam Ravnborg 2985d4f3e350SEd Wildgooseconfig ALIX 2986d4f3e350SEd Wildgoose bool "PCEngines ALIX System Support (LED setup)" 2987d4f3e350SEd Wildgoose select GPIOLIB 2988a7f7f624SMasahiro Yamada help 2989d4f3e350SEd Wildgoose This option enables system support for the PCEngines ALIX. 2990d4f3e350SEd Wildgoose At present this just sets up LEDs for GPIO control on 2991d4f3e350SEd Wildgoose ALIX2/3/6 boards. However, other system specific setup should 2992d4f3e350SEd Wildgoose get added here. 2993d4f3e350SEd Wildgoose 2994d4f3e350SEd Wildgoose Note: You must still enable the drivers for GPIO and LED support 2995d4f3e350SEd Wildgoose (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2996d4f3e350SEd Wildgoose 2997d4f3e350SEd Wildgoose Note: You have to set alix.force=1 for boards with Award BIOS. 2998d4f3e350SEd Wildgoose 2999da4e3302SPhilip Prindevilleconfig NET5501 3000da4e3302SPhilip Prindeville bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 3001da4e3302SPhilip Prindeville select GPIOLIB 3002a7f7f624SMasahiro Yamada help 3003da4e3302SPhilip Prindeville This option enables system support for the Soekris Engineering net5501. 3004da4e3302SPhilip Prindeville 30053197059aSPhilip A. Prindevilleconfig GEOS 30063197059aSPhilip A. Prindeville bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 30073197059aSPhilip A. Prindeville select GPIOLIB 30083197059aSPhilip A. Prindeville depends on DMI 3009a7f7f624SMasahiro Yamada help 30103197059aSPhilip A. Prindeville This option enables system support for the Traverse Technologies GEOS. 30113197059aSPhilip A. Prindeville 30127d029125SVivien Didelotconfig TS5500 30137d029125SVivien Didelot bool "Technologic Systems TS-5500 platform support" 30147d029125SVivien Didelot depends on MELAN 30157d029125SVivien Didelot select CHECK_SIGNATURE 30167d029125SVivien Didelot select NEW_LEDS 30177d029125SVivien Didelot select LEDS_CLASS 3018a7f7f624SMasahiro Yamada help 30197d029125SVivien Didelot This option enables system support for the Technologic Systems TS-5500. 30207d029125SVivien Didelot 3021e279b6c1SSam Ravnborgendif # X86_32 3022e279b6c1SSam Ravnborg 302323ac4ae8SAndreas Herrmannconfig AMD_NB 3024e279b6c1SSam Ravnborg def_bool y 30250e152cd7SBorislav Petkov depends on CPU_SUP_AMD && PCI 3026e279b6c1SSam Ravnborg 3027e279b6c1SSam Ravnborgendmenu 3028e279b6c1SSam Ravnborg 30291572497cSChristoph Hellwigmenu "Binary Emulations" 3030e279b6c1SSam Ravnborg 3031e279b6c1SSam Ravnborgconfig IA32_EMULATION 3032e279b6c1SSam Ravnborg bool "IA32 Emulation" 3033e279b6c1SSam Ravnborg depends on X86_64 303439f88911SIngo Molnar select ARCH_WANT_OLD_COMPAT_IPC 3035d1603990SRandy Dunlap select BINFMT_ELF 303639f88911SIngo Molnar select COMPAT_OLD_SIGACTION 3037a7f7f624SMasahiro Yamada help 30385fd92e65SH. J. Lu Include code to run legacy 32-bit programs under a 30395fd92e65SH. J. Lu 64-bit kernel. You should likely turn this on, unless you're 30405fd92e65SH. J. Lu 100% sure that you don't have any 32-bit programs left. 3041e279b6c1SSam Ravnborg 304283a44a4fSMasahiro Yamadaconfig X86_X32_ABI 30436ea30386SKees Cook bool "x32 ABI for 64-bit mode" 30449b54050bSBrian Gerst depends on X86_64 3045aaeed6ecSNathan Chancellor # llvm-objcopy does not convert x86_64 .note.gnu.property or 3046aaeed6ecSNathan Chancellor # compressed debug sections to x86_x32 properly: 3047aaeed6ecSNathan Chancellor # https://github.com/ClangBuiltLinux/linux/issues/514 3048aaeed6ecSNathan Chancellor # https://github.com/ClangBuiltLinux/linux/issues/1141 3049aaeed6ecSNathan Chancellor depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm) 3050a7f7f624SMasahiro Yamada help 30515fd92e65SH. J. Lu Include code to run binaries for the x32 native 32-bit ABI 30525fd92e65SH. J. Lu for 64-bit processors. An x32 process gets access to the 30535fd92e65SH. J. Lu full 64-bit register file and wide data path while leaving 30545fd92e65SH. J. Lu pointers at 32 bits for smaller memory footprint. 30555fd92e65SH. J. Lu 3056953fee1dSIngo Molnarconfig COMPAT_32 3057953fee1dSIngo Molnar def_bool y 3058953fee1dSIngo Molnar depends on IA32_EMULATION || X86_32 3059953fee1dSIngo Molnar select HAVE_UID16 3060953fee1dSIngo Molnar select OLD_SIGSUSPEND3 3061953fee1dSIngo Molnar 3062e279b6c1SSam Ravnborgconfig COMPAT 30633c2362e6SHarvey Harrison def_bool y 306483a44a4fSMasahiro Yamada depends on IA32_EMULATION || X86_X32_ABI 3065e279b6c1SSam Ravnborg 3066e279b6c1SSam Ravnborgconfig COMPAT_FOR_U64_ALIGNMENT 30673120e25eSJan Beulich def_bool y 3068a9251280SLinus Torvalds depends on COMPAT 3069ee009e4aSDavid Howells 3070e279b6c1SSam Ravnborgendmenu 3071e279b6c1SSam Ravnborg 3072e5beae16SKeith Packardconfig HAVE_ATOMIC_IOMAP 3073e5beae16SKeith Packard def_bool y 3074e5beae16SKeith Packard depends on X86_32 3075e5beae16SKeith Packard 3076edf88417SAvi Kivitysource "arch/x86/kvm/Kconfig" 30775e8ebd84SJason A. Donenfeld 30785e8ebd84SJason A. Donenfeldsource "arch/x86/Kconfig.assembler" 3079