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 30d94e0685SIngo Molnar select ARCH_USE_CMPXCHG_LOCKREF 31d94e0685SIngo Molnar select HAVE_ARCH_SOFT_DIRTY 32d94e0685SIngo Molnar select MODULES_USE_ELF_RELA 33f616ab59SChristoph Hellwig select NEED_DMA_MAP_STATE 3409230cbcSChristoph Hellwig select SWIOTLB 357facdc42SAl Viro select ARCH_HAS_ELFCORE_COMPAT 3663703f37SKefeng Wang select ZONE_DMA32 371032c0baSSam Ravnborg 38518049d9SSteven Rostedt (VMware)config FORCE_DYNAMIC_FTRACE 39518049d9SSteven Rostedt (VMware) def_bool y 40518049d9SSteven Rostedt (VMware) depends on X86_32 41518049d9SSteven Rostedt (VMware) depends on FUNCTION_TRACER 42518049d9SSteven Rostedt (VMware) select DYNAMIC_FTRACE 43518049d9SSteven Rostedt (VMware) help 44518049d9SSteven Rostedt (VMware) We keep the static function tracing (!DYNAMIC_FTRACE) around 45518049d9SSteven Rostedt (VMware) in order to test the non static function tracing in the 46518049d9SSteven Rostedt (VMware) generic code, as other architectures still use it. But we 47518049d9SSteven Rostedt (VMware) only need to keep it around for x86_64. No need to keep it 48518049d9SSteven Rostedt (VMware) for x86_32. For x86_32, force DYNAMIC_FTRACE. 49d94e0685SIngo Molnar# 50d94e0685SIngo Molnar# Arch settings 51d94e0685SIngo Molnar# 52d94e0685SIngo Molnar# ( Note that options that are marked 'if X86_64' could in principle be 53d94e0685SIngo Molnar# ported to 32-bit as well. ) 54d94e0685SIngo Molnar# 558d5fffb9SSam Ravnborgconfig X86 563c2362e6SHarvey Harrison def_bool y 57c763ea26SIngo Molnar # 58c763ea26SIngo Molnar # Note: keep this list sorted alphabetically 59c763ea26SIngo Molnar # 606471b825SIngo Molnar select ACPI_LEGACY_TABLES_LOOKUP if ACPI 616e0a0ea1SGraeme Gregory select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI 62942fa985SYury Norov select ARCH_32BIT_OFF_T if X86_32 632a21ad57SThomas Gleixner select ARCH_CLOCKSOURCE_INIT 641f6d3a8fSMasami Hiramatsu select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 651e866974SAnshuman Khandual select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION 665c11f00bSDavid Hildenbrand select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64 6791024b3cSAnshuman Khandual select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG 68cebc774fSAnshuman Khandual select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE) 691e866974SAnshuman Khandual select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE 7091dda51aSAleksey Makarov select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI 71c2280be8SAnshuman Khandual select ARCH_HAS_CACHE_LINE_SIZE 722792d84eSKees Cook select ARCH_HAS_CURRENT_STACK_POINTER 73fa5b6ec9SLaura Abbott select ARCH_HAS_DEBUG_VIRTUAL 74399145f9SAnshuman Khandual select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE 7521266be9SDan Williams select ARCH_HAS_DEVMEM_IS_ALLOWED 76b1a57bbfSDouglas Anderson select ARCH_HAS_EARLY_DEBUG if KGDB 776471b825SIngo Molnar select ARCH_HAS_ELF_RANDOMIZE 7872d93104SLinus Torvalds select ARCH_HAS_FAST_MULTIPLIER 79316d097cSDave Hansen select ARCH_HAS_FILTER_PGPROT 806974f0c4SDaniel Micay select ARCH_HAS_FORTIFY_SOURCE 81957e3facSRiku Voipio select ARCH_HAS_GCOV_PROFILE_ALL 82bece04b5SMarco Elver select ARCH_HAS_KCOV if X86_64 830c9c1d56SThiago Jung Bauermann select ARCH_HAS_MEM_ENCRYPT 8410bcc80eSMathieu Desnoyers select ARCH_HAS_MEMBARRIER_SYNC_CORE 850ebeea8cSDaniel Borkmann select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 86c763ea26SIngo Molnar select ARCH_HAS_PMEM_API if X86_64 8717596731SRobin Murphy select ARCH_HAS_PTE_DEVMAP if X86_64 883010a5eaSLaurent Dufour select ARCH_HAS_PTE_SPECIAL 890aed55afSDan Williams select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 90ec6347bbSDan Williams select ARCH_HAS_COPY_MC if X86_64 91d2852a22SDaniel Borkmann select ARCH_HAS_SET_MEMORY 92d253ca0cSRick Edgecombe select ARCH_HAS_SET_DIRECT_MAP 93ad21fc4fSLaura Abbott select ARCH_HAS_STRICT_KERNEL_RWX 94ad21fc4fSLaura Abbott select ARCH_HAS_STRICT_MODULE_RWX 95ac1ab12aSMathieu Desnoyers select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE 9625c619e5SBrian Gerst select ARCH_HAS_SYSCALL_WRAPPER 97c6d30853SAndrey Ryabinin select ARCH_HAS_UBSAN_SANITIZE_ALL 987e01ccb4SZong Li select ARCH_HAS_DEBUG_WX 9963703f37SKefeng Wang select ARCH_HAS_ZONE_DMA_SET if EXPERT 1006471b825SIngo Molnar select ARCH_HAVE_NMI_SAFE_CMPXCHG 1016471b825SIngo Molnar select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI 10277fbbc81SMark Salter select ARCH_MIGHT_HAVE_PC_PARPORT 1035e2c18c0SMark Salter select ARCH_MIGHT_HAVE_PC_SERIO 1043599fe12SThomas Gleixner select ARCH_STACKWALK 1052c870e61SArnd Bergmann select ARCH_SUPPORTS_ACPI 1066471b825SIngo Molnar select ARCH_SUPPORTS_ATOMIC_RMW 1075d6ad668SMike Rapoport select ARCH_SUPPORTS_DEBUG_PAGEALLOC 108d283d422SPasha Tatashin select ARCH_SUPPORTS_PAGE_TABLE_CHECK if X86_64 1096471b825SIngo Molnar select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 11014df3267SThomas Gleixner select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 111583bfd48SNathan Chancellor select ARCH_SUPPORTS_LTO_CLANG 112583bfd48SNathan Chancellor select ARCH_SUPPORTS_LTO_CLANG_THIN 1136471b825SIngo Molnar select ARCH_USE_BUILTIN_BSWAP 114dce44566SAnshuman Khandual select ARCH_USE_MEMTEST 1156471b825SIngo Molnar select ARCH_USE_QUEUED_RWLOCKS 1166471b825SIngo Molnar select ARCH_USE_QUEUED_SPINLOCKS 1172ce0d7f9SMark Brown select ARCH_USE_SYM_ANNOTATIONS 118ce4a4e56SAndy Lutomirski select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 11981c22041SDaniel Borkmann select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 120c763ea26SIngo Molnar select ARCH_WANTS_DYNAMIC_TASK_STRUCT 12151c2ee6dSNick Desaulniers select ARCH_WANTS_NO_INSTR 12207431506SAnshuman Khandual select ARCH_WANT_GENERAL_HUGETLB 1233876d4a3SAlexandre Ghiti select ARCH_WANT_HUGE_PMD_SHARE 12459612b24SNathan Chancellor select ARCH_WANT_LD_ORPHAN_WARN 12538d8b4e6SHuang Ying select ARCH_WANTS_THP_SWAP if X86_64 126b5f06f64SBalbir Singh select ARCH_HAS_PARANOID_L1D_FLUSH 12710916706SShile Zhang select BUILDTIME_TABLE_SORT 1286471b825SIngo Molnar select CLKEVT_I8253 1296471b825SIngo Molnar select CLOCKSOURCE_VALIDATE_LAST_CYCLE 1306471b825SIngo Molnar select CLOCKSOURCE_WATCHDOG 1316471b825SIngo Molnar select DCACHE_WORD_ACCESS 1323aac3ebeSThomas Gleixner select DYNAMIC_SIGFRAME 13345471cd9SLinus Torvalds select EDAC_ATOMIC_SCRUB 13445471cd9SLinus Torvalds select EDAC_SUPPORT 1356471b825SIngo Molnar select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) 1366471b825SIngo Molnar select GENERIC_CLOCKEVENTS_MIN_ADJUST 1376471b825SIngo Molnar select GENERIC_CMOS_UPDATE 1386471b825SIngo Molnar select GENERIC_CPU_AUTOPROBE 13961dc0f55SThomas Gleixner select GENERIC_CPU_VULNERABILITIES 1406471b825SIngo Molnar select GENERIC_EARLY_IOREMAP 14127d6b4d1SThomas Gleixner select GENERIC_ENTRY 1426471b825SIngo Molnar select GENERIC_IOMAP 143c7d6c9ddSThomas Gleixner select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP 1440fa115daSThomas Gleixner select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC 145ad7a929fSThomas Gleixner select GENERIC_IRQ_MIGRATION if SMP 1466471b825SIngo Molnar select GENERIC_IRQ_PROBE 147c201c917SThomas Gleixner select GENERIC_IRQ_RESERVATION_MODE 1486471b825SIngo Molnar select GENERIC_IRQ_SHOW 1496471b825SIngo Molnar select GENERIC_PENDING_IRQ if SMP 1502ae27137SSteven Price select GENERIC_PTDUMP 1516471b825SIngo Molnar select GENERIC_SMP_IDLE_THREAD 1526471b825SIngo Molnar select GENERIC_TIME_VSYSCALL 1537ac87074SVincenzo Frascino select GENERIC_GETTIMEOFDAY 154550a77a7SDmitry Safonov select GENERIC_VDSO_TIME_NS 15539656e83SChristoph Hellwig select GUP_GET_PTE_LOW_HIGH if X86_PAE 15617e5888eSHans de Goede select HARDIRQS_SW_RESEND 1577edaeb68SThomas Gleixner select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 1586471b825SIngo Molnar select HAVE_ACPI_APEI if ACPI 1596471b825SIngo Molnar select HAVE_ACPI_APEI_NMI if ACPI 1606471b825SIngo Molnar select HAVE_ALIGNED_STRUCT_PAGE if SLUB 1616471b825SIngo Molnar select HAVE_ARCH_AUDITSYSCALL 1626471b825SIngo Molnar select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE 163eed1fceeSSong Liu select HAVE_ARCH_HUGE_VMALLOC if X86_64 1646471b825SIngo Molnar select HAVE_ARCH_JUMP_LABEL 165b34006c4SArd Biesheuvel select HAVE_ARCH_JUMP_LABEL_RELATIVE 166d17a1d97SAndrey Ryabinin select HAVE_ARCH_KASAN if X86_64 1670609ae01SDaniel Axtens select HAVE_ARCH_KASAN_VMALLOC if X86_64 1681dc0da6eSAlexander Potapenko select HAVE_ARCH_KFENCE 1696471b825SIngo Molnar select HAVE_ARCH_KGDB 1709e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_BITS if MMU 1719e08f57dSDaniel Cashman select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT 1721b028f78SDmitry Safonov select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT 173271ca788SArd Biesheuvel select HAVE_ARCH_PREL32_RELOCATIONS 1746471b825SIngo Molnar select HAVE_ARCH_SECCOMP_FILTER 175f7d83c1cSKees Cook select HAVE_ARCH_THREAD_STRUCT_WHITELIST 176afaef01cSAlexander Popov select HAVE_ARCH_STACKLEAK 1776471b825SIngo Molnar select HAVE_ARCH_TRACEHOOK 1786471b825SIngo Molnar select HAVE_ARCH_TRANSPARENT_HUGEPAGE 179a00cc7d9SMatthew Wilcox select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 180b64d8d1eSPeter Xu select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD 1817677f7fdSAxel Rasmussen select HAVE_ARCH_USERFAULTFD_MINOR if X86_64 && USERFAULTFD 182e37e43a4SAndy Lutomirski select HAVE_ARCH_VMAP_STACK if X86_64 183fe950f60SKees Cook select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET 184c763ea26SIngo Molnar select HAVE_ARCH_WITHIN_STACK_FRAMES 1852ff2b7ecSMasahiro Yamada select HAVE_ASM_MODVERSIONS 1866471b825SIngo Molnar select HAVE_CMPXCHG_DOUBLE 1876471b825SIngo Molnar select HAVE_CMPXCHG_LOCAL 1886471b825SIngo Molnar select HAVE_CONTEXT_TRACKING if X86_64 189d1f250e2SFrederic Weisbecker select HAVE_CONTEXT_TRACKING_OFFSTACK if HAVE_CONTEXT_TRACKING 1906471b825SIngo Molnar select HAVE_C_RECORDMCOUNT 19103f16cd0SJosh Poimboeuf select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL 1924ed308c4SSteven Rostedt (Google) select HAVE_BUILDTIME_MCOUNT_SORT 1936471b825SIngo Molnar select HAVE_DEBUG_KMEMLEAK 1949c5a3621SAkinobu Mita select HAVE_DMA_CONTIGUOUS 195677aa9f7SSteven Rostedt select HAVE_DYNAMIC_FTRACE 19606aeaaeaSMasami Hiramatsu select HAVE_DYNAMIC_FTRACE_WITH_REGS 19702a474caSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 198562955feSSteven Rostedt (VMware) select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 199c316eb44SHeiko Carstens select HAVE_SAMPLE_FTRACE_DIRECT if X86_64 200503e4510SHeiko Carstens select HAVE_SAMPLE_FTRACE_DIRECT_MULTI if X86_64 20103f5781bSWang YanQing select HAVE_EBPF_JIT 20258340a07SJohannes Berg select HAVE_EFFICIENT_UNALIGNED_ACCESS 2036630a8e5SChristoph Hellwig select HAVE_EISA 2045f56a5dfSJiri Slaby select HAVE_EXIT_THREAD 20567a929e0SChristoph Hellwig select HAVE_FAST_GUP 206644e0e8dSSteven Rostedt (VMware) select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE 2076471b825SIngo Molnar select HAVE_FTRACE_MCOUNT_RECORD 2084a30e4c9SSteven Rostedt (VMware) select HAVE_FUNCTION_GRAPH_TRACER if X86_32 || (X86_64 && DYNAMIC_FTRACE) 2096471b825SIngo Molnar select HAVE_FUNCTION_TRACER 2106b90bd4bSEmese Revfy select HAVE_GCC_PLUGINS 2110067f129SK.Prasad select HAVE_HW_BREAKPOINT 2126471b825SIngo Molnar select HAVE_IOREMAP_PROT 213624db9eaSThomas Gleixner select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 2146471b825SIngo Molnar select HAVE_IRQ_TIME_ACCOUNTING 2154ab7674fSJosh Poimboeuf select HAVE_JUMP_LABEL_HACK if HAVE_OBJTOOL 2166471b825SIngo Molnar select HAVE_KERNEL_BZIP2 2176471b825SIngo Molnar select HAVE_KERNEL_GZIP 2186471b825SIngo Molnar select HAVE_KERNEL_LZ4 2196471b825SIngo Molnar select HAVE_KERNEL_LZMA 2206471b825SIngo Molnar select HAVE_KERNEL_LZO 2216471b825SIngo Molnar select HAVE_KERNEL_XZ 222fb46d057SNick Terrell select HAVE_KERNEL_ZSTD 2236471b825SIngo Molnar select HAVE_KPROBES 2246471b825SIngo Molnar select HAVE_KPROBES_ON_FTRACE 225540adea3SMasami Hiramatsu select HAVE_FUNCTION_ERROR_INJECTION 2266471b825SIngo Molnar select HAVE_KRETPROBES 227f3a112c0SMasami Hiramatsu select HAVE_RETHOOK 2286471b825SIngo Molnar select HAVE_KVM 2296471b825SIngo Molnar select HAVE_LIVEPATCH if X86_64 2300102752eSFrederic Weisbecker select HAVE_MIXED_BREAKPOINTS_REGS 231ee9f8fceSJosh Poimboeuf select HAVE_MOD_ARCH_SPECIFIC 2329f132f7eSJoel Fernandes (Google) select HAVE_MOVE_PMD 233be37c98dSKalesh Singh select HAVE_MOVE_PUD 234*22102f45SJosh Poimboeuf select HAVE_NOINSTR_HACK if HAVE_OBJTOOL 23542a0bb3fSPetr Mladek select HAVE_NMI 23603f16cd0SJosh Poimboeuf select HAVE_OBJTOOL if X86_64 2376471b825SIngo Molnar select HAVE_OPTPROBES 2386471b825SIngo Molnar select HAVE_PCSPKR_PLATFORM 2396471b825SIngo Molnar select HAVE_PERF_EVENTS 240c01d4323SFrederic Weisbecker select HAVE_PERF_EVENTS_NMI 24192e5aae4SNicholas Piggin select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI 242eb01d42aSChristoph Hellwig select HAVE_PCI 243c5e63197SJiri Olsa select HAVE_PERF_REGS 244c5ebcedbSJiri Olsa select HAVE_PERF_USER_STACK_DUMP 245ff2e6d72SPeter Zijlstra select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT 24600998085SThomas Gleixner select HAVE_POSIX_CPU_TIMERS_TASK_WORK 2476471b825SIngo Molnar select HAVE_REGS_AND_STACK_ACCESS_API 24803f16cd0SJosh Poimboeuf select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC || STACK_VALIDATION 2493c88ee19SMasami Hiramatsu select HAVE_FUNCTION_ARG_ACCESS_API 2507ecd19cfSKefeng Wang select HAVE_SETUP_PER_CPU_AREA 251cd1a41ceSThomas Gleixner select HAVE_SOFTIRQ_ON_OWN_STACK 252d148eac0SMasahiro Yamada select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR 25303f16cd0SJosh Poimboeuf select HAVE_STACK_VALIDATION if HAVE_OBJTOOL 254e6d6c071SJosh Poimboeuf select HAVE_STATIC_CALL 25503f16cd0SJosh Poimboeuf select HAVE_STATIC_CALL_INLINE if HAVE_OBJTOOL 25699cf983cSMark Rutland select HAVE_PREEMPT_DYNAMIC_CALL 257d6761b8fSMathieu Desnoyers select HAVE_RSEQ 2586471b825SIngo Molnar select HAVE_SYSCALL_TRACEPOINTS 2596471b825SIngo Molnar select HAVE_UNSTABLE_SCHED_CLOCK 2607c68af6eSAvi Kivity select HAVE_USER_RETURN_NOTIFIER 2617ac87074SVincenzo Frascino select HAVE_GENERIC_VDSO 26205736e4aSThomas Gleixner select HOTPLUG_SMT if SMP 263c0185808SThomas Gleixner select IRQ_FORCED_THREADING 2647ecd19cfSKefeng Wang select NEED_PER_CPU_EMBED_FIRST_CHUNK 2657ecd19cfSKefeng Wang select NEED_PER_CPU_PAGE_FIRST_CHUNK 26686596f0aSChristoph Hellwig select NEED_SG_DMA_LENGTH 2672eac9c2dSChristoph Hellwig select PCI_DOMAINS if PCI 268625210cfSSinan Kaya select PCI_LOCKLESS_CONFIG if PCI 2696471b825SIngo Molnar select PERF_EVENTS 2703195ef59SPrarit Bhargava select RTC_LIB 271d6faca40SArnd Bergmann select RTC_MC146818_LIB 2726471b825SIngo Molnar select SPARSE_IRQ 27383fe27eaSPranith Kumar select SRCU 2746471b825SIngo Molnar select SYSCTL_EXCEPTION_TRACE 27515f4eae7SAndy Lutomirski select THREAD_INFO_IN_TASK 2764aae683fSMasahiro Yamada select TRACE_IRQFLAGS_SUPPORT 2776471b825SIngo Molnar select USER_STACKTRACE_SUPPORT 2786471b825SIngo Molnar select VIRT_TO_BUS 2793b02a051SIngo Molnar select HAVE_ARCH_KCSAN if X86_64 2806471b825SIngo Molnar select X86_FEATURE_NAMES if PROC_FS 2810c608dadSAubrey Li select PROC_PID_ARCH_STATUS if PROC_FS 28250468e43SJarkko Sakkinen select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX 2839e2b4be3SNayna Jain imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI 2847d8330a5SBalbir Singh 285ba7e4d13SIngo Molnarconfig INSTRUCTION_DECODER 2863120e25eSJan Beulich def_bool y 2873120e25eSJan Beulich depends on KPROBES || PERF_EVENTS || UPROBES 288ba7e4d13SIngo Molnar 28951b26adaSLinus Torvaldsconfig OUTPUT_FORMAT 29051b26adaSLinus Torvalds string 29151b26adaSLinus Torvalds default "elf32-i386" if X86_32 29251b26adaSLinus Torvalds default "elf64-x86-64" if X86_64 29351b26adaSLinus Torvalds 2948d5fffb9SSam Ravnborgconfig LOCKDEP_SUPPORT 2953c2362e6SHarvey Harrison def_bool y 2968d5fffb9SSam Ravnborg 2978d5fffb9SSam Ravnborgconfig STACKTRACE_SUPPORT 2983c2362e6SHarvey Harrison def_bool y 2998d5fffb9SSam Ravnborg 3008d5fffb9SSam Ravnborgconfig MMU 3013c2362e6SHarvey Harrison def_bool y 3028d5fffb9SSam Ravnborg 3039e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MIN 3049e08f57dSDaniel Cashman default 28 if 64BIT 3059e08f57dSDaniel Cashman default 8 3069e08f57dSDaniel Cashman 3079e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MAX 3089e08f57dSDaniel Cashman default 32 if 64BIT 3099e08f57dSDaniel Cashman default 16 3109e08f57dSDaniel Cashman 3119e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MIN 3129e08f57dSDaniel Cashman default 8 3139e08f57dSDaniel Cashman 3149e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MAX 3159e08f57dSDaniel Cashman default 16 3169e08f57dSDaniel Cashman 3178d5fffb9SSam Ravnborgconfig SBUS 3188d5fffb9SSam Ravnborg bool 3198d5fffb9SSam Ravnborg 3208d5fffb9SSam Ravnborgconfig GENERIC_ISA_DMA 3213120e25eSJan Beulich def_bool y 3223120e25eSJan Beulich depends on ISA_DMA_API 3238d5fffb9SSam Ravnborg 3248d5fffb9SSam Ravnborgconfig GENERIC_BUG 3253c2362e6SHarvey Harrison def_bool y 3268d5fffb9SSam Ravnborg depends on BUG 327b93a531eSJan Beulich select GENERIC_BUG_RELATIVE_POINTERS if X86_64 328b93a531eSJan Beulich 329b93a531eSJan Beulichconfig GENERIC_BUG_RELATIVE_POINTERS 330b93a531eSJan Beulich bool 3318d5fffb9SSam Ravnborg 3328d5fffb9SSam Ravnborgconfig ARCH_MAY_HAVE_PC_FDC 3333120e25eSJan Beulich def_bool y 3343120e25eSJan Beulich depends on ISA_DMA_API 3358d5fffb9SSam Ravnborg 3361032c0baSSam Ravnborgconfig GENERIC_CALIBRATE_DELAY 3371032c0baSSam Ravnborg def_bool y 3381032c0baSSam Ravnborg 3399a0b8415Svenkatesh.pallipadi@intel.comconfig ARCH_HAS_CPU_RELAX 3409a0b8415Svenkatesh.pallipadi@intel.com def_bool y 3418d5fffb9SSam Ravnborg 342801e4062SJohannes Bergconfig ARCH_HIBERNATION_POSSIBLE 343801e4062SJohannes Berg def_bool y 344801e4062SJohannes Berg 345d7109fe3SAndy Shevchenkoconfig ARCH_NR_GPIO 346d7109fe3SAndy Shevchenko int 347d7109fe3SAndy Shevchenko default 1024 if X86_64 348d7109fe3SAndy Shevchenko default 512 349d7109fe3SAndy Shevchenko 350f4cb5700SJohannes Bergconfig ARCH_SUSPEND_POSSIBLE 351f4cb5700SJohannes Berg def_bool y 352f4cb5700SJohannes Berg 3538d5fffb9SSam Ravnborgconfig AUDIT_ARCH 354e0fd24a3SJan Beulich def_bool y if X86_64 3558d5fffb9SSam Ravnborg 356d6f2d75aSAndrey Ryabininconfig KASAN_SHADOW_OFFSET 357d6f2d75aSAndrey Ryabinin hex 358d6f2d75aSAndrey Ryabinin depends on KASAN 359d6f2d75aSAndrey Ryabinin default 0xdffffc0000000000 360d6f2d75aSAndrey Ryabinin 36169575d38SShane Wangconfig HAVE_INTEL_TXT 36269575d38SShane Wang def_bool y 3636ea30386SKees Cook depends on INTEL_IOMMU && ACPI 36469575d38SShane Wang 3656b0c3d44SSam Ravnborgconfig X86_32_SMP 3666b0c3d44SSam Ravnborg def_bool y 3676b0c3d44SSam Ravnborg depends on X86_32 && SMP 3686b0c3d44SSam Ravnborg 3696b0c3d44SSam Ravnborgconfig X86_64_SMP 3706b0c3d44SSam Ravnborg def_bool y 3716b0c3d44SSam Ravnborg depends on X86_64 && SMP 3726b0c3d44SSam Ravnborg 3732b144498SSrikar Dronamrajuconfig ARCH_SUPPORTS_UPROBES 3742b144498SSrikar Dronamraju def_bool y 3752b144498SSrikar Dronamraju 376d20642f0SRob Herringconfig FIX_EARLYCON_MEM 377d20642f0SRob Herring def_bool y 378d20642f0SRob Herring 37994d49eb3SKirill A. Shutemovconfig DYNAMIC_PHYSICAL_MASK 38094d49eb3SKirill A. Shutemov bool 38194d49eb3SKirill A. Shutemov 38298233368SKirill A. Shutemovconfig PGTABLE_LEVELS 38398233368SKirill A. Shutemov int 38477ef56e4SKirill A. Shutemov default 5 if X86_5LEVEL 38598233368SKirill A. Shutemov default 4 if X86_64 38698233368SKirill A. Shutemov default 3 if X86_PAE 38798233368SKirill A. Shutemov default 2 38898233368SKirill A. Shutemov 3892a61f474SMasahiro Yamadaconfig CC_HAS_SANE_STACKPROTECTOR 3902a61f474SMasahiro Yamada bool 3912a61f474SMasahiro Yamada default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT 3922a61f474SMasahiro Yamada default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC)) 3932a61f474SMasahiro Yamada help 3942a61f474SMasahiro Yamada We have to make sure stack protector is unconditionally disabled if 3953fb0fdb3SAndy Lutomirski the compiler produces broken code or if it does not let us control 3963fb0fdb3SAndy Lutomirski the segment on 32-bit kernels. 3972a61f474SMasahiro Yamada 398506f1d07SSam Ravnborgmenu "Processor type and features" 399506f1d07SSam Ravnborg 400506f1d07SSam Ravnborgconfig SMP 401506f1d07SSam Ravnborg bool "Symmetric multi-processing support" 402a7f7f624SMasahiro Yamada help 403506f1d07SSam Ravnborg This enables support for systems with more than one CPU. If you have 4044a474157SRobert Graffham a system with only one CPU, say N. If you have a system with more 4054a474157SRobert Graffham than one CPU, say Y. 406506f1d07SSam Ravnborg 4074a474157SRobert Graffham If you say N here, the kernel will run on uni- and multiprocessor 408506f1d07SSam Ravnborg machines, but will use only one CPU of a multiprocessor machine. If 409506f1d07SSam Ravnborg you say Y here, the kernel will run on many, but not all, 4104a474157SRobert Graffham uniprocessor machines. On a uniprocessor machine, the kernel 411506f1d07SSam Ravnborg will run faster if you say N here. 412506f1d07SSam Ravnborg 413506f1d07SSam Ravnborg Note that if you say Y here and choose architecture "586" or 414506f1d07SSam Ravnborg "Pentium" under "Processor family", the kernel will not work on 486 415506f1d07SSam Ravnborg architectures. Similarly, multiprocessor kernels for the "PPro" 416506f1d07SSam Ravnborg architecture may not work on all Pentium based boards. 417506f1d07SSam Ravnborg 418506f1d07SSam Ravnborg People using multiprocessor machines who say Y here should also say 419506f1d07SSam Ravnborg Y to "Enhanced Real Time Clock Support", below. The "Advanced Power 420506f1d07SSam Ravnborg Management" code will be disabled if you say Y here. 421506f1d07SSam Ravnborg 422cb1aaebeSMauro Carvalho Chehab See also <file:Documentation/x86/i386/IO-APIC.rst>, 4234f4cfa6cSMauro Carvalho Chehab <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at 424506f1d07SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 425506f1d07SSam Ravnborg 426506f1d07SSam Ravnborg If you don't know what to do here, say N. 427506f1d07SSam Ravnborg 4289def39beSJosh Triplettconfig X86_FEATURE_NAMES 4299def39beSJosh Triplett bool "Processor feature human-readable names" if EMBEDDED 4309def39beSJosh Triplett default y 431a7f7f624SMasahiro Yamada help 4329def39beSJosh Triplett This option compiles in a table of x86 feature bits and corresponding 4339def39beSJosh Triplett names. This is required to support /proc/cpuinfo and a few kernel 4349def39beSJosh Triplett messages. You can disable this to save space, at the expense of 4359def39beSJosh Triplett making those few kernel messages show numeric feature bits instead. 4369def39beSJosh Triplett 4379def39beSJosh Triplett If in doubt, say Y. 4389def39beSJosh Triplett 43906cd9a7dSYinghai Luconfig X86_X2APIC 44006cd9a7dSYinghai Lu bool "Support x2apic" 44119e3d60dSJan Kiszka depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST) 442a7f7f624SMasahiro Yamada help 44306cd9a7dSYinghai Lu This enables x2apic support on CPUs that have this feature. 44406cd9a7dSYinghai Lu 44506cd9a7dSYinghai Lu This allows 32-bit apic IDs (so it can support very large systems), 44606cd9a7dSYinghai Lu and accesses the local apic via MSRs not via mmio. 44706cd9a7dSYinghai Lu 44806cd9a7dSYinghai Lu If you don't know what to do here, say N. 44906cd9a7dSYinghai Lu 4506695c85bSYinghai Luconfig X86_MPPARSE 4514590d98fSAndy Shevchenko bool "Enable MPS table" if ACPI 4527a527688SJan Beulich default y 4535ab74722SIngo Molnar depends on X86_LOCAL_APIC 454a7f7f624SMasahiro Yamada help 4556695c85bSYinghai Lu For old smp systems that do not have proper acpi support. Newer systems 4566695c85bSYinghai Lu (esp with 64bit cpus) with acpi support, MADT and DSDT will override it 4576695c85bSYinghai Lu 458ddd70cf9SJun Nakajimaconfig GOLDFISH 459ddd70cf9SJun Nakajima def_bool y 460ddd70cf9SJun Nakajima depends on X86_GOLDFISH 461ddd70cf9SJun Nakajima 46276b04384SDavid Woodhouseconfig RETPOLINE 46376b04384SDavid Woodhouse bool "Avoid speculative indirect branches in kernel" 46403f16cd0SJosh Poimboeuf select OBJTOOL if HAVE_OBJTOOL 46576b04384SDavid Woodhouse default y 46676b04384SDavid Woodhouse help 46776b04384SDavid Woodhouse Compile kernel with the retpoline compiler options to guard against 46876b04384SDavid Woodhouse kernel-to-user data leaks by avoiding speculative indirect 46976b04384SDavid Woodhouse branches. Requires a compiler with -mindirect-branch=thunk-extern 47076b04384SDavid Woodhouse support for full protection. The kernel may run slower. 47176b04384SDavid Woodhouse 472e463a09aSPeter Zijlstraconfig CC_HAS_SLS 473e463a09aSPeter Zijlstra def_bool $(cc-option,-mharden-sls=all) 474e463a09aSPeter Zijlstra 475e463a09aSPeter Zijlstraconfig SLS 476e463a09aSPeter Zijlstra bool "Mitigate Straight-Line-Speculation" 477e463a09aSPeter Zijlstra depends on CC_HAS_SLS && X86_64 47803f16cd0SJosh Poimboeuf select OBJTOOL if HAVE_OBJTOOL 479e463a09aSPeter Zijlstra default n 480e463a09aSPeter Zijlstra help 481e463a09aSPeter Zijlstra Compile the kernel with straight-line-speculation options to guard 482e463a09aSPeter Zijlstra against straight line speculation. The kernel image might be slightly 483e463a09aSPeter Zijlstra larger. 484e463a09aSPeter Zijlstra 485e6d42931SJohannes Weinerconfig X86_CPU_RESCTRL 486e6d42931SJohannes Weiner bool "x86 CPU resource control support" 4876fe07ce3SBabu Moger depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) 48859fe5a77SThomas Gleixner select KERNFS 489e79f15a4SChen Yu select PROC_CPU_RESCTRL if PROC_FS 49078e99b4aSFenghua Yu help 491e6d42931SJohannes Weiner Enable x86 CPU resource control support. 4926fe07ce3SBabu Moger 4936fe07ce3SBabu Moger Provide support for the allocation and monitoring of system resources 4946fe07ce3SBabu Moger usage by the CPU. 4956fe07ce3SBabu Moger 4966fe07ce3SBabu Moger Intel calls this Intel Resource Director Technology 4976fe07ce3SBabu Moger (Intel(R) RDT). More information about RDT can be found in the 4986fe07ce3SBabu Moger Intel x86 Architecture Software Developer Manual. 4996fe07ce3SBabu Moger 5006fe07ce3SBabu Moger AMD calls this AMD Platform Quality of Service (AMD QoS). 5016fe07ce3SBabu Moger More information about AMD QoS can be found in the AMD64 Technology 5026fe07ce3SBabu Moger Platform Quality of Service Extensions manual. 50378e99b4aSFenghua Yu 50478e99b4aSFenghua Yu Say N if unsure. 50578e99b4aSFenghua Yu 5068425091fSRavikiran G Thirumalaiif X86_32 507a0d0bb4dSRandy Dunlapconfig X86_BIGSMP 508a0d0bb4dSRandy Dunlap bool "Support for big SMP systems with more than 8 CPUs" 509a0d0bb4dSRandy Dunlap depends on SMP 510a7f7f624SMasahiro Yamada help 511e133f6eaSRandy Dunlap This option is needed for the systems that have more than 8 CPUs. 512a0d0bb4dSRandy Dunlap 513c5c606d9SRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 514c5c606d9SRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 515c5c606d9SRavikiran G Thirumalai default y 516a7f7f624SMasahiro Yamada help 51706ac8346SIngo Molnar If you disable this option then the kernel will only support 51806ac8346SIngo Molnar standard PC platforms. (which covers the vast majority of 51906ac8346SIngo Molnar systems out there.) 52006ac8346SIngo Molnar 5218425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5228425091fSRavikiran G Thirumalai for the following (non-PC) 32 bit x86 platforms: 523cb7b8023SBen Hutchings Goldfish (Android emulator) 5248425091fSRavikiran G Thirumalai AMD Elan 5258425091fSRavikiran G Thirumalai RDC R-321x SoC 5268425091fSRavikiran G Thirumalai SGI 320/540 (Visual Workstation) 52783125a3aSAlessandro Rubini STA2X11-based (e.g. Northville) 5283f4110a4SThomas Gleixner Moorestown MID devices 52906ac8346SIngo Molnar 53006ac8346SIngo Molnar If you have one of these systems, or if you want to build a 53106ac8346SIngo Molnar generic distribution kernel, say Y here - otherwise say N. 5328425091fSRavikiran G Thirumalaiendif 53306ac8346SIngo Molnar 5348425091fSRavikiran G Thirumalaiif X86_64 5358425091fSRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM 5368425091fSRavikiran G Thirumalai bool "Support for extended (non-PC) x86 platforms" 5378425091fSRavikiran G Thirumalai default y 538a7f7f624SMasahiro Yamada help 5398425091fSRavikiran G Thirumalai If you disable this option then the kernel will only support 5408425091fSRavikiran G Thirumalai standard PC platforms. (which covers the vast majority of 5418425091fSRavikiran G Thirumalai systems out there.) 5428425091fSRavikiran G Thirumalai 5438425091fSRavikiran G Thirumalai If you enable this option then you'll be able to select support 5448425091fSRavikiran G Thirumalai for the following (non-PC) 64 bit x86 platforms: 54544b111b5SSteffen Persvold Numascale NumaChip 5468425091fSRavikiran G Thirumalai ScaleMP vSMP 5478425091fSRavikiran G Thirumalai SGI Ultraviolet 5488425091fSRavikiran G Thirumalai 5498425091fSRavikiran G Thirumalai If you have one of these systems, or if you want to build a 5508425091fSRavikiran G Thirumalai generic distribution kernel, say Y here - otherwise say N. 5518425091fSRavikiran G Thirumalaiendif 552c5c606d9SRavikiran G Thirumalai# This is an alphabetically sorted list of 64 bit extended platforms 553c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 55444b111b5SSteffen Persvoldconfig X86_NUMACHIP 55544b111b5SSteffen Persvold bool "Numascale NumaChip" 55644b111b5SSteffen Persvold depends on X86_64 55744b111b5SSteffen Persvold depends on X86_EXTENDED_PLATFORM 55844b111b5SSteffen Persvold depends on NUMA 55944b111b5SSteffen Persvold depends on SMP 56044b111b5SSteffen Persvold depends on X86_X2APIC 561f9726bfdSDaniel J Blueman depends on PCI_MMCONFIG 562a7f7f624SMasahiro Yamada help 56344b111b5SSteffen Persvold Adds support for Numascale NumaChip large-SMP systems. Needed to 56444b111b5SSteffen Persvold enable more than ~168 cores. 56544b111b5SSteffen Persvold If you don't have one of these, you should say N here. 56603b48632SNick Piggin 5676a48565eSIngo Molnarconfig X86_VSMP 568c5c606d9SRavikiran G Thirumalai bool "ScaleMP vSMP" 5696276a074SBorislav Petkov select HYPERVISOR_GUEST 5706a48565eSIngo Molnar select PARAVIRT 5716a48565eSIngo Molnar depends on X86_64 && PCI 572c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 573ead91d4bSShai Fultheim depends on SMP 574a7f7f624SMasahiro Yamada help 5756a48565eSIngo Molnar Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is 5766a48565eSIngo Molnar supposed to run on these EM64T-based machines. Only choose this option 5776a48565eSIngo Molnar if you have one of these machines. 5786a48565eSIngo Molnar 579c5c606d9SRavikiran G Thirumalaiconfig X86_UV 580c5c606d9SRavikiran G Thirumalai bool "SGI Ultraviolet" 581c5c606d9SRavikiran G Thirumalai depends on X86_64 582c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 58354c28d29SJack Steiner depends on NUMA 5841ecb4ae5SAndrew Morton depends on EFI 585c2209ea5SIngo Molnar depends on KEXEC_CORE 5869d6c26e7SSuresh Siddha depends on X86_X2APIC 5871222e564SIngo Molnar depends on PCI 588a7f7f624SMasahiro Yamada help 589c5c606d9SRavikiran G Thirumalai This option is needed in order to support SGI Ultraviolet systems. 590c5c606d9SRavikiran G Thirumalai If you don't have one of these, you should say N here. 591c5c606d9SRavikiran G Thirumalai 592c5c606d9SRavikiran G Thirumalai# Following is an alphabetically sorted list of 32 bit extended platforms 593c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions 594506f1d07SSam Ravnborg 595ddd70cf9SJun Nakajimaconfig X86_GOLDFISH 596ddd70cf9SJun Nakajima bool "Goldfish (Virtual Platform)" 597cb7b8023SBen Hutchings depends on X86_EXTENDED_PLATFORM 598a7f7f624SMasahiro Yamada help 599ddd70cf9SJun Nakajima Enable support for the Goldfish virtual platform used primarily 600ddd70cf9SJun Nakajima for Android development. Unless you are building for the Android 601ddd70cf9SJun Nakajima Goldfish emulator say N here. 602ddd70cf9SJun Nakajima 603c751e17bSThomas Gleixnerconfig X86_INTEL_CE 604c751e17bSThomas Gleixner bool "CE4100 TV platform" 605c751e17bSThomas Gleixner depends on PCI 606c751e17bSThomas Gleixner depends on PCI_GODIRECT 6076084a6e2SJiang Liu depends on X86_IO_APIC 608c751e17bSThomas Gleixner depends on X86_32 609c751e17bSThomas Gleixner depends on X86_EXTENDED_PLATFORM 61037bc9f50SDirk Brandewie select X86_REBOOTFIXUPS 611da6b737bSSebastian Andrzej Siewior select OF 612da6b737bSSebastian Andrzej Siewior select OF_EARLY_FLATTREE 613a7f7f624SMasahiro Yamada help 614c751e17bSThomas Gleixner Select for the Intel CE media processor (CE4100) SOC. 615c751e17bSThomas Gleixner This option compiles in support for the CE4100 SOC for settop 616c751e17bSThomas Gleixner boxes and media devices. 617c751e17bSThomas Gleixner 6184cb9b00fSDavid Cohenconfig X86_INTEL_MID 61943605ef1SAlan Cox bool "Intel MID platform support" 62043605ef1SAlan Cox depends on X86_EXTENDED_PLATFORM 621edc6bc78SDavid Cohen depends on X86_PLATFORM_DEVICES 6221ea7c673SAlan Cox depends on PCI 6233fda5bb4SAndy Shevchenko depends on X86_64 || (PCI_GOANY && X86_32) 6241ea7c673SAlan Cox depends on X86_IO_APIC 6254cb9b00fSDavid Cohen select I2C 6267c9c3a1eSAlan Cox select DW_APB_TIMER 62754b34aa0SMika Westerberg select INTEL_SCU_PCI 628a7f7f624SMasahiro Yamada help 6294cb9b00fSDavid Cohen Select to build a kernel capable of supporting Intel MID (Mobile 6304cb9b00fSDavid Cohen Internet Device) platform systems which do not have the PCI legacy 6314cb9b00fSDavid Cohen interfaces. If you are building for a PC class system say N here. 6321ea7c673SAlan Cox 6334cb9b00fSDavid Cohen Intel MID platforms are based on an Intel processor and chipset which 6344cb9b00fSDavid Cohen consume less power than most of the x86 derivatives. 63543605ef1SAlan Cox 6368bbc2a13SBryan O'Donoghueconfig X86_INTEL_QUARK 6378bbc2a13SBryan O'Donoghue bool "Intel Quark platform support" 6388bbc2a13SBryan O'Donoghue depends on X86_32 6398bbc2a13SBryan O'Donoghue depends on X86_EXTENDED_PLATFORM 6408bbc2a13SBryan O'Donoghue depends on X86_PLATFORM_DEVICES 6418bbc2a13SBryan O'Donoghue depends on X86_TSC 6428bbc2a13SBryan O'Donoghue depends on PCI 6438bbc2a13SBryan O'Donoghue depends on PCI_GOANY 6448bbc2a13SBryan O'Donoghue depends on X86_IO_APIC 6458bbc2a13SBryan O'Donoghue select IOSF_MBI 6468bbc2a13SBryan O'Donoghue select INTEL_IMR 6479ab6eb51SAndy Shevchenko select COMMON_CLK 648a7f7f624SMasahiro Yamada help 6498bbc2a13SBryan O'Donoghue Select to include support for Quark X1000 SoC. 6508bbc2a13SBryan O'Donoghue Say Y here if you have a Quark based system such as the Arduino 6518bbc2a13SBryan O'Donoghue compatible Intel Galileo. 6528bbc2a13SBryan O'Donoghue 6533d48aab1SMika Westerbergconfig X86_INTEL_LPSS 6543d48aab1SMika Westerberg bool "Intel Low Power Subsystem Support" 6555962dd22SSinan Kaya depends on X86 && ACPI && PCI 6563d48aab1SMika Westerberg select COMMON_CLK 6570f531431SMathias Nyman select PINCTRL 658eebb3e8dSAndy Shevchenko select IOSF_MBI 659a7f7f624SMasahiro Yamada help 6603d48aab1SMika Westerberg Select to build support for Intel Low Power Subsystem such as 6613d48aab1SMika Westerberg found on Intel Lynxpoint PCH. Selecting this option enables 6620f531431SMathias Nyman things like clock tree (common clock framework) and pincontrol 6630f531431SMathias Nyman which are needed by the LPSS peripheral drivers. 6643d48aab1SMika Westerberg 66592082a88SKen Xueconfig X86_AMD_PLATFORM_DEVICE 66692082a88SKen Xue bool "AMD ACPI2Platform devices support" 66792082a88SKen Xue depends on ACPI 66892082a88SKen Xue select COMMON_CLK 66992082a88SKen Xue select PINCTRL 670a7f7f624SMasahiro Yamada help 67192082a88SKen Xue Select to interpret AMD specific ACPI device to platform device 67292082a88SKen Xue such as I2C, UART, GPIO found on AMD Carrizo and later chipsets. 67392082a88SKen Xue I2C and UART depend on COMMON_CLK to set clock. GPIO driver is 67492082a88SKen Xue implemented under PINCTRL subsystem. 67592082a88SKen Xue 676ced3ce76SDavid E. Boxconfig IOSF_MBI 677ced3ce76SDavid E. Box tristate "Intel SoC IOSF Sideband support for SoC platforms" 678ced3ce76SDavid E. Box depends on PCI 679a7f7f624SMasahiro Yamada help 680ced3ce76SDavid E. Box This option enables sideband register access support for Intel SoC 681ced3ce76SDavid E. Box platforms. On these platforms the IOSF sideband is used in lieu of 682ced3ce76SDavid E. Box MSR's for some register accesses, mostly but not limited to thermal 683ced3ce76SDavid E. Box and power. Drivers may query the availability of this device to 684ced3ce76SDavid E. Box determine if they need the sideband in order to work on these 685ced3ce76SDavid E. Box platforms. The sideband is available on the following SoC products. 686ced3ce76SDavid E. Box This list is not meant to be exclusive. 687ced3ce76SDavid E. Box - BayTrail 688ced3ce76SDavid E. Box - Braswell 689ced3ce76SDavid E. Box - Quark 690ced3ce76SDavid E. Box 691ced3ce76SDavid E. Box You should say Y if you are running a kernel on one of these SoC's. 692ced3ce76SDavid E. Box 693ed2226bdSDavid E. Boxconfig IOSF_MBI_DEBUG 694ed2226bdSDavid E. Box bool "Enable IOSF sideband access through debugfs" 695ed2226bdSDavid E. Box depends on IOSF_MBI && DEBUG_FS 696a7f7f624SMasahiro Yamada help 697ed2226bdSDavid E. Box Select this option to expose the IOSF sideband access registers (MCR, 698ed2226bdSDavid E. Box MDR, MCRX) through debugfs to write and read register information from 699ed2226bdSDavid E. Box different units on the SoC. This is most useful for obtaining device 700ed2226bdSDavid E. Box state information for debug and analysis. As this is a general access 701ed2226bdSDavid E. Box mechanism, users of this option would have specific knowledge of the 702ed2226bdSDavid E. Box device they want to access. 703ed2226bdSDavid E. Box 704ed2226bdSDavid E. Box If you don't require the option or are in doubt, say N. 705ed2226bdSDavid E. Box 706c5c606d9SRavikiran G Thirumalaiconfig X86_RDC321X 707c5c606d9SRavikiran G Thirumalai bool "RDC R-321x SoC" 708506f1d07SSam Ravnborg depends on X86_32 709c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 710c5c606d9SRavikiran G Thirumalai select M486 711c5c606d9SRavikiran G Thirumalai select X86_REBOOTFIXUPS 712a7f7f624SMasahiro Yamada help 713c5c606d9SRavikiran G Thirumalai This option is needed for RDC R-321x system-on-chip, also known 714c5c606d9SRavikiran G Thirumalai as R-8610-(G). 715c5c606d9SRavikiran G Thirumalai If you don't have one of these chips, you should say N here. 716c5c606d9SRavikiran G Thirumalai 717e0c7ae37SIngo Molnarconfig X86_32_NON_STANDARD 7189c398017SIngo Molnar bool "Support non-standard 32-bit SMP architectures" 7199c398017SIngo Molnar depends on X86_32 && SMP 720c5c606d9SRavikiran G Thirumalai depends on X86_EXTENDED_PLATFORM 721a7f7f624SMasahiro Yamada help 722b5660ba7SH. Peter Anvin This option compiles in the bigsmp and STA2X11 default 723b5660ba7SH. Peter Anvin subarchitectures. It is intended for a generic binary 724b5660ba7SH. Peter Anvin kernel. If you select them all, kernel will probe it one by 725b5660ba7SH. Peter Anvin one and will fallback to default. 726d49c4288SYinghai Lu 727c5c606d9SRavikiran G Thirumalai# Alphabetically sorted list of Non standard 32 bit platforms 728d49c4288SYinghai Lu 729d949f36fSLinus Torvaldsconfig X86_SUPPORTS_MEMORY_FAILURE 7306fc108a0SJan Beulich def_bool y 731d949f36fSLinus Torvalds # MCE code calls memory_failure(): 732d949f36fSLinus Torvalds depends on X86_MCE 733d949f36fSLinus Torvalds # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags: 734d949f36fSLinus Torvalds # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH: 735d949f36fSLinus Torvalds depends on X86_64 || !SPARSEMEM 736d949f36fSLinus Torvalds select ARCH_SUPPORTS_MEMORY_FAILURE 737d949f36fSLinus Torvalds 73883125a3aSAlessandro Rubiniconfig STA2X11 73983125a3aSAlessandro Rubini bool "STA2X11 Companion Chip Support" 74083125a3aSAlessandro Rubini depends on X86_32_NON_STANDARD && PCI 74183125a3aSAlessandro Rubini select SWIOTLB 74283125a3aSAlessandro Rubini select MFD_STA2X11 7430145071bSLinus Walleij select GPIOLIB 744a7f7f624SMasahiro Yamada help 74583125a3aSAlessandro Rubini This adds support for boards based on the STA2X11 IO-Hub, 74683125a3aSAlessandro Rubini a.k.a. "ConneXt". The chip is used in place of the standard 74783125a3aSAlessandro Rubini PC chipset, so all "standard" peripherals are missing. If this 74883125a3aSAlessandro Rubini option is selected the kernel will still be able to boot on 74983125a3aSAlessandro Rubini standard PC machines. 75083125a3aSAlessandro Rubini 75182148d1dSShérabconfig X86_32_IRIS 75282148d1dSShérab tristate "Eurobraille/Iris poweroff module" 75382148d1dSShérab depends on X86_32 754a7f7f624SMasahiro Yamada help 75582148d1dSShérab The Iris machines from EuroBraille do not have APM or ACPI support 75682148d1dSShérab to shut themselves down properly. A special I/O sequence is 75782148d1dSShérab needed to do so, which is what this module does at 75882148d1dSShérab kernel shutdown. 75982148d1dSShérab 76082148d1dSShérab This is only for Iris machines from EuroBraille. 76182148d1dSShérab 76282148d1dSShérab If unused, say N. 76382148d1dSShérab 764ae1e9130SIngo Molnarconfig SCHED_OMIT_FRAME_POINTER 7653c2362e6SHarvey Harrison def_bool y 7663c2362e6SHarvey Harrison prompt "Single-depth WCHAN output" 767a87d0914SKen Chen depends on X86 768a7f7f624SMasahiro Yamada help 769506f1d07SSam Ravnborg Calculate simpler /proc/<PID>/wchan values. If this option 770506f1d07SSam Ravnborg is disabled then wchan values will recurse back to the 771506f1d07SSam Ravnborg caller function. This provides more accurate wchan values, 772506f1d07SSam Ravnborg at the expense of slightly more scheduling overhead. 773506f1d07SSam Ravnborg 774506f1d07SSam Ravnborg If in doubt, say "Y". 775506f1d07SSam Ravnborg 7766276a074SBorislav Petkovmenuconfig HYPERVISOR_GUEST 7776276a074SBorislav Petkov bool "Linux guest support" 778a7f7f624SMasahiro Yamada help 7796276a074SBorislav Petkov Say Y here to enable options for running Linux under various hyper- 7806276a074SBorislav Petkov visors. This option enables basic hypervisor detection and platform 7816276a074SBorislav Petkov setup. 782506f1d07SSam Ravnborg 7836276a074SBorislav Petkov If you say N, all options in this submenu will be skipped and 7846276a074SBorislav Petkov disabled, and Linux guest support won't be built in. 785506f1d07SSam Ravnborg 7866276a074SBorislav Petkovif HYPERVISOR_GUEST 787506f1d07SSam Ravnborg 788e61bd94aSEduardo Pereira Habkostconfig PARAVIRT 789e61bd94aSEduardo Pereira Habkost bool "Enable paravirtualization code" 790a0e2bf7cSJuergen Gross depends on HAVE_STATIC_CALL 791a7f7f624SMasahiro Yamada help 792e61bd94aSEduardo Pereira Habkost This changes the kernel so it can modify itself when it is run 793e61bd94aSEduardo Pereira Habkost under a hypervisor, potentially improving performance significantly 794e61bd94aSEduardo Pereira Habkost over full virtualization. However, when run without a hypervisor 795e61bd94aSEduardo Pereira Habkost the kernel is theoretically slower and slightly larger. 796e61bd94aSEduardo Pereira Habkost 797c00a280aSJuergen Grossconfig PARAVIRT_XXL 798c00a280aSJuergen Gross bool 799c00a280aSJuergen Gross 8006276a074SBorislav Petkovconfig PARAVIRT_DEBUG 8016276a074SBorislav Petkov bool "paravirt-ops debugging" 8026276a074SBorislav Petkov depends on PARAVIRT && DEBUG_KERNEL 803a7f7f624SMasahiro Yamada help 8046276a074SBorislav Petkov Enable to debug paravirt_ops internals. Specifically, BUG if 8056276a074SBorislav Petkov a paravirt_op is missing when it is called. 8066276a074SBorislav Petkov 807b4ecc126SJeremy Fitzhardingeconfig PARAVIRT_SPINLOCKS 808b4ecc126SJeremy Fitzhardinge bool "Paravirtualization layer for spinlocks" 8096ea30386SKees Cook depends on PARAVIRT && SMP 810a7f7f624SMasahiro Yamada help 811b4ecc126SJeremy Fitzhardinge Paravirtualized spinlocks allow a pvops backend to replace the 812b4ecc126SJeremy Fitzhardinge spinlock implementation with something virtualization-friendly 813b4ecc126SJeremy Fitzhardinge (for example, block the virtual CPU rather than spinning). 814b4ecc126SJeremy Fitzhardinge 8154c4e4f61SRaghavendra K T It has a minimal impact on native kernels and gives a nice performance 8164c4e4f61SRaghavendra K T benefit on paravirtualized KVM / Xen kernels. 817b4ecc126SJeremy Fitzhardinge 8184c4e4f61SRaghavendra K T If you are unsure how to answer this question, answer Y. 819b4ecc126SJeremy Fitzhardinge 820ecca2502SZhao Yakuiconfig X86_HV_CALLBACK_VECTOR 821ecca2502SZhao Yakui def_bool n 822ecca2502SZhao Yakui 8236276a074SBorislav Petkovsource "arch/x86/xen/Kconfig" 8246276a074SBorislav Petkov 8256276a074SBorislav Petkovconfig KVM_GUEST 8266276a074SBorislav Petkov bool "KVM Guest support (including kvmclock)" 8276276a074SBorislav Petkov depends on PARAVIRT 8286276a074SBorislav Petkov select PARAVIRT_CLOCK 829a1c4423bSMarcelo Tosatti select ARCH_CPUIDLE_HALTPOLL 830b1d40575SVitaly Kuznetsov select X86_HV_CALLBACK_VECTOR 8316276a074SBorislav Petkov default y 832a7f7f624SMasahiro Yamada help 8336276a074SBorislav Petkov This option enables various optimizations for running under the KVM 8346276a074SBorislav Petkov hypervisor. It includes a paravirtualized clock, so that instead 8356276a074SBorislav Petkov of relying on a PIT (or probably other) emulation by the 8366276a074SBorislav Petkov underlying device model, the host provides the guest with 8376276a074SBorislav Petkov timing infrastructure such as time of day, and system time 8386276a074SBorislav Petkov 839a1c4423bSMarcelo Tosatticonfig ARCH_CPUIDLE_HALTPOLL 840a1c4423bSMarcelo Tosatti def_bool n 841a1c4423bSMarcelo Tosatti prompt "Disable host haltpoll when loading haltpoll driver" 842a1c4423bSMarcelo Tosatti help 843a1c4423bSMarcelo Tosatti If virtualized under KVM, disable host haltpoll. 844a1c4423bSMarcelo Tosatti 8457733607fSMaran Wilsonconfig PVH 8467733607fSMaran Wilson bool "Support for running PVH guests" 847a7f7f624SMasahiro Yamada help 8487733607fSMaran Wilson This option enables the PVH entry point for guest virtual machines 8497733607fSMaran Wilson as specified in the x86/HVM direct boot ABI. 8507733607fSMaran Wilson 8516276a074SBorislav Petkovconfig PARAVIRT_TIME_ACCOUNTING 8526276a074SBorislav Petkov bool "Paravirtual steal time accounting" 8536276a074SBorislav Petkov depends on PARAVIRT 854a7f7f624SMasahiro Yamada help 8556276a074SBorislav Petkov Select this option to enable fine granularity task steal time 8566276a074SBorislav Petkov accounting. Time spent executing other tasks in parallel with 8576276a074SBorislav Petkov the current vCPU is discounted from the vCPU power. To account for 8586276a074SBorislav Petkov that, there can be a small performance impact. 8596276a074SBorislav Petkov 8606276a074SBorislav Petkov If in doubt, say N here. 8616276a074SBorislav Petkov 8627af192c9SGerd Hoffmannconfig PARAVIRT_CLOCK 8637af192c9SGerd Hoffmann bool 8647af192c9SGerd Hoffmann 8654a362601SJan Kiszkaconfig JAILHOUSE_GUEST 8664a362601SJan Kiszka bool "Jailhouse non-root cell support" 867abde587bSArnd Bergmann depends on X86_64 && PCI 86887e65d05SJan Kiszka select X86_PM_TIMER 869a7f7f624SMasahiro Yamada help 8704a362601SJan Kiszka This option allows to run Linux as guest in a Jailhouse non-root 8714a362601SJan Kiszka cell. You can leave this option disabled if you only want to start 8724a362601SJan Kiszka Jailhouse and run Linux afterwards in the root cell. 8734a362601SJan Kiszka 874ec7972c9SZhao Yakuiconfig ACRN_GUEST 875ec7972c9SZhao Yakui bool "ACRN Guest support" 876ec7972c9SZhao Yakui depends on X86_64 877498ad393SZhao Yakui select X86_HV_CALLBACK_VECTOR 878ec7972c9SZhao Yakui help 879ec7972c9SZhao Yakui This option allows to run Linux as guest in the ACRN hypervisor. ACRN is 880ec7972c9SZhao Yakui a flexible, lightweight reference open-source hypervisor, built with 881ec7972c9SZhao Yakui real-time and safety-criticality in mind. It is built for embedded 882ec7972c9SZhao Yakui IOT with small footprint and real-time features. More details can be 883ec7972c9SZhao Yakui found in https://projectacrn.org/. 884ec7972c9SZhao Yakui 8856276a074SBorislav Petkovendif #HYPERVISOR_GUEST 88697349135SJeremy Fitzhardinge 887506f1d07SSam Ravnborgsource "arch/x86/Kconfig.cpu" 888506f1d07SSam Ravnborg 889506f1d07SSam Ravnborgconfig HPET_TIMER 8903c2362e6SHarvey Harrison def_bool X86_64 891506f1d07SSam Ravnborg prompt "HPET Timer Support" if X86_32 892a7f7f624SMasahiro Yamada help 893506f1d07SSam Ravnborg Use the IA-PC HPET (High Precision Event Timer) to manage 894506f1d07SSam Ravnborg time in preference to the PIT and RTC, if a HPET is 895506f1d07SSam Ravnborg present. 896506f1d07SSam Ravnborg HPET is the next generation timer replacing legacy 8254s. 897506f1d07SSam Ravnborg The HPET provides a stable time base on SMP 898506f1d07SSam Ravnborg systems, unlike the TSC, but it is more expensive to access, 8994e7f9df2SMichael S. Tsirkin as it is off-chip. The interface used is documented 9004e7f9df2SMichael S. Tsirkin in the HPET spec, revision 1. 901506f1d07SSam Ravnborg 902506f1d07SSam Ravnborg You can safely choose Y here. However, HPET will only be 903506f1d07SSam Ravnborg activated if the platform and the BIOS support this feature. 904506f1d07SSam Ravnborg Otherwise the 8254 will be used for timing services. 905506f1d07SSam Ravnborg 906506f1d07SSam Ravnborg Choose N to continue using the legacy 8254 timer. 907506f1d07SSam Ravnborg 908506f1d07SSam Ravnborgconfig HPET_EMULATE_RTC 9093c2362e6SHarvey Harrison def_bool y 9103228e1dcSAnand K Mistry depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y) 911506f1d07SSam Ravnborg 9126a108a14SDavid Rientjes# Mark as expert because too many people got it wrong. 913506f1d07SSam Ravnborg# The code disables itself when not needed. 9147ae9392cSThomas Petazzoniconfig DMI 9157ae9392cSThomas Petazzoni default y 916cf074402SArd Biesheuvel select DMI_SCAN_MACHINE_NON_EFI_FALLBACK 9176a108a14SDavid Rientjes bool "Enable DMI scanning" if EXPERT 918a7f7f624SMasahiro Yamada help 9197ae9392cSThomas Petazzoni Enabled scanning of DMI to identify machine quirks. Say Y 9207ae9392cSThomas Petazzoni here unless you have verified that your setup is not 9217ae9392cSThomas Petazzoni affected by entries in the DMI blacklist. Required by PNP 9227ae9392cSThomas Petazzoni BIOS code. 9237ae9392cSThomas Petazzoni 924506f1d07SSam Ravnborgconfig GART_IOMMU 92538901f1cSAndi Kleen bool "Old AMD GART IOMMU support" 9262f9237d4SChristoph Hellwig select DMA_OPS 927a4ce5a48SChristoph Hellwig select IOMMU_HELPER 928506f1d07SSam Ravnborg select SWIOTLB 92923ac4ae8SAndreas Herrmann depends on X86_64 && PCI && AMD_NB 930a7f7f624SMasahiro Yamada help 931ced3c42cSIngo Molnar Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron 932ced3c42cSIngo Molnar GART based hardware IOMMUs. 933ced3c42cSIngo Molnar 934ced3c42cSIngo Molnar The GART supports full DMA access for devices with 32-bit access 935ced3c42cSIngo Molnar limitations, on systems with more than 3 GB. This is usually needed 936ced3c42cSIngo Molnar for USB, sound, many IDE/SATA chipsets and some other devices. 937ced3c42cSIngo Molnar 938ced3c42cSIngo Molnar Newer systems typically have a modern AMD IOMMU, supported via 939ced3c42cSIngo Molnar the CONFIG_AMD_IOMMU=y config option. 940ced3c42cSIngo Molnar 941ced3c42cSIngo Molnar In normal configurations this driver is only active when needed: 942ced3c42cSIngo Molnar there's more than 3 GB of memory and the system contains a 943ced3c42cSIngo Molnar 32-bit limited device. 944ced3c42cSIngo Molnar 945ced3c42cSIngo Molnar If unsure, say Y. 946506f1d07SSam Ravnborg 9471184dc2fSMike Travisconfig MAXSMP 948ddb0c5a6SSamuel Thibault bool "Enable Maximum number of SMP Processors and NUMA Nodes" 9496ea30386SKees Cook depends on X86_64 && SMP && DEBUG_KERNEL 95036f5101aSMike Travis select CPUMASK_OFFSTACK 951a7f7f624SMasahiro Yamada help 952ddb0c5a6SSamuel Thibault Enable maximum number of CPUS and NUMA Nodes for this architecture. 9531184dc2fSMike Travis If unsure, say N. 954506f1d07SSam Ravnborg 955aec6487eSIngo Molnar# 956aec6487eSIngo Molnar# The maximum number of CPUs supported: 957aec6487eSIngo Molnar# 958aec6487eSIngo Molnar# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT, 959aec6487eSIngo Molnar# and which can be configured interactively in the 960aec6487eSIngo Molnar# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range. 961aec6487eSIngo Molnar# 962aec6487eSIngo Molnar# The ranges are different on 32-bit and 64-bit kernels, depending on 963aec6487eSIngo Molnar# hardware capabilities and scalability features of the kernel. 964aec6487eSIngo Molnar# 965aec6487eSIngo Molnar# ( If MAXSMP is enabled we just use the highest possible value and disable 966aec6487eSIngo Molnar# interactive configuration. ) 967aec6487eSIngo Molnar# 968a0d0bb4dSRandy Dunlap 969aec6487eSIngo Molnarconfig NR_CPUS_RANGE_BEGIN 970a0d0bb4dSRandy Dunlap int 971aec6487eSIngo Molnar default NR_CPUS_RANGE_END if MAXSMP 972a0d0bb4dSRandy Dunlap default 1 if !SMP 973a0d0bb4dSRandy Dunlap default 2 974a0d0bb4dSRandy Dunlap 975aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 976a0d0bb4dSRandy Dunlap int 977a0d0bb4dSRandy Dunlap depends on X86_32 978aec6487eSIngo Molnar default 64 if SMP && X86_BIGSMP 979aec6487eSIngo Molnar default 8 if SMP && !X86_BIGSMP 980a0d0bb4dSRandy Dunlap default 1 if !SMP 981a0d0bb4dSRandy Dunlap 982aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END 983a0d0bb4dSRandy Dunlap int 984a0d0bb4dSRandy Dunlap depends on X86_64 9851edae1aeSScott Wood default 8192 if SMP && CPUMASK_OFFSTACK 9861edae1aeSScott Wood default 512 if SMP && !CPUMASK_OFFSTACK 987a0d0bb4dSRandy Dunlap default 1 if !SMP 988aec6487eSIngo Molnar 989aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 990aec6487eSIngo Molnar int 991aec6487eSIngo Molnar depends on X86_32 992aec6487eSIngo Molnar default 32 if X86_BIGSMP 993aec6487eSIngo Molnar default 8 if SMP 994aec6487eSIngo Molnar default 1 if !SMP 995aec6487eSIngo Molnar 996aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT 997aec6487eSIngo Molnar int 998aec6487eSIngo Molnar depends on X86_64 999a0d0bb4dSRandy Dunlap default 8192 if MAXSMP 1000a0d0bb4dSRandy Dunlap default 64 if SMP 1001aec6487eSIngo Molnar default 1 if !SMP 1002a0d0bb4dSRandy Dunlap 1003506f1d07SSam Ravnborgconfig NR_CPUS 100436f5101aSMike Travis int "Maximum number of CPUs" if SMP && !MAXSMP 1005aec6487eSIngo Molnar range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END 1006aec6487eSIngo Molnar default NR_CPUS_DEFAULT 1007a7f7f624SMasahiro Yamada help 1008506f1d07SSam Ravnborg This allows you to specify the maximum number of CPUs which this 1009bb61ccc7SJosh Boyer kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum 1010cad14bb9SKirill A. Shutemov supported value is 8192, otherwise the maximum value is 512. The 1011506f1d07SSam Ravnborg minimum value which makes sense is 2. 1012506f1d07SSam Ravnborg 1013aec6487eSIngo Molnar This is purely to save memory: each supported CPU adds about 8KB 1014aec6487eSIngo Molnar to the kernel image. 1015506f1d07SSam Ravnborg 101666558b73STim Chenconfig SCHED_CLUSTER 101766558b73STim Chen bool "Cluster scheduler support" 101866558b73STim Chen depends on SMP 101966558b73STim Chen default y 102066558b73STim Chen help 102166558b73STim Chen Cluster scheduler support improves the CPU scheduler's decision 102266558b73STim Chen making when dealing with machines that have clusters of CPUs. 102366558b73STim Chen Cluster usually means a couple of CPUs which are placed closely 102466558b73STim Chen by sharing mid-level caches, last-level cache tags or internal 102566558b73STim Chen busses. 102666558b73STim Chen 1027506f1d07SSam Ravnborgconfig SCHED_SMT 1028dbe73364SThomas Gleixner def_bool y if SMP 1029506f1d07SSam Ravnborg 1030506f1d07SSam Ravnborgconfig SCHED_MC 10313c2362e6SHarvey Harrison def_bool y 10323c2362e6SHarvey Harrison prompt "Multi-core scheduler support" 1033c8e56d20SBorislav Petkov depends on SMP 1034a7f7f624SMasahiro Yamada help 1035506f1d07SSam Ravnborg Multi-core scheduler support improves the CPU scheduler's decision 1036506f1d07SSam Ravnborg making when dealing with multi-core CPU chips at a cost of slightly 1037506f1d07SSam Ravnborg increased overhead in some places. If unsure say N here. 1038506f1d07SSam Ravnborg 1039de966cf4STim Chenconfig SCHED_MC_PRIO 1040de966cf4STim Chen bool "CPU core priorities scheduler support" 10410a21fc12SIngo Molnar depends on SCHED_MC && CPU_SUP_INTEL 10420a21fc12SIngo Molnar select X86_INTEL_PSTATE 10430a21fc12SIngo Molnar select CPU_FREQ 1044de966cf4STim Chen default y 1045a7f7f624SMasahiro Yamada help 1046de966cf4STim Chen Intel Turbo Boost Max Technology 3.0 enabled CPUs have a 1047de966cf4STim Chen core ordering determined at manufacturing time, which allows 1048de966cf4STim Chen certain cores to reach higher turbo frequencies (when running 1049de966cf4STim Chen single threaded workloads) than others. 1050de966cf4STim Chen 1051de966cf4STim Chen Enabling this kernel feature teaches the scheduler about 1052de966cf4STim Chen the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the 1053de966cf4STim Chen scheduler's CPU selection logic accordingly, so that higher 1054de966cf4STim Chen overall system performance can be achieved. 1055de966cf4STim Chen 1056de966cf4STim Chen This feature will have no effect on CPUs without this feature. 1057de966cf4STim Chen 1058de966cf4STim Chen If unsure say Y here. 10595e76b2abSTim Chen 106030b8b006SThomas Gleixnerconfig UP_LATE_INIT 106130b8b006SThomas Gleixner def_bool y 1062ba360f88SThomas Gleixner depends on !SMP && X86_LOCAL_APIC 106330b8b006SThomas Gleixner 1064506f1d07SSam Ravnborgconfig X86_UP_APIC 106550849eefSJan Beulich bool "Local APIC support on uniprocessors" if !PCI_MSI 106650849eefSJan Beulich default PCI_MSI 106738a1dfdaSBryan O'Donoghue depends on X86_32 && !SMP && !X86_32_NON_STANDARD 1068a7f7f624SMasahiro Yamada help 1069506f1d07SSam Ravnborg A local APIC (Advanced Programmable Interrupt Controller) is an 1070506f1d07SSam Ravnborg integrated interrupt controller in the CPU. If you have a single-CPU 1071506f1d07SSam Ravnborg system which has a processor with a local APIC, you can say Y here to 1072506f1d07SSam Ravnborg enable and use it. If you say Y here even though your machine doesn't 1073506f1d07SSam Ravnborg have a local APIC, then the kernel will still run with no slowdown at 1074506f1d07SSam Ravnborg all. The local APIC supports CPU-generated self-interrupts (timer, 1075506f1d07SSam Ravnborg performance counters), and the NMI watchdog which detects hard 1076506f1d07SSam Ravnborg lockups. 1077506f1d07SSam Ravnborg 1078506f1d07SSam Ravnborgconfig X86_UP_IOAPIC 1079506f1d07SSam Ravnborg bool "IO-APIC support on uniprocessors" 1080506f1d07SSam Ravnborg depends on X86_UP_APIC 1081a7f7f624SMasahiro Yamada help 1082506f1d07SSam Ravnborg An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an 1083506f1d07SSam Ravnborg SMP-capable replacement for PC-style interrupt controllers. Most 1084506f1d07SSam Ravnborg SMP systems and many recent uniprocessor systems have one. 1085506f1d07SSam Ravnborg 1086506f1d07SSam Ravnborg If you have a single-CPU system with an IO-APIC, you can say Y here 1087506f1d07SSam Ravnborg to use it. If you say Y here even though your machine doesn't have 1088506f1d07SSam Ravnborg an IO-APIC, then the kernel will still run with no slowdown at all. 1089506f1d07SSam Ravnborg 1090506f1d07SSam Ravnborgconfig X86_LOCAL_APIC 10913c2362e6SHarvey Harrison def_bool y 10920dbc6078SThomas Petazzoni depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI 1093b5dc8e6cSJiang Liu select IRQ_DOMAIN_HIERARCHY 109452f518a3SJiang Liu select PCI_MSI_IRQ_DOMAIN if PCI_MSI 1095506f1d07SSam Ravnborg 1096506f1d07SSam Ravnborgconfig X86_IO_APIC 1097b1da1e71SJan Beulich def_bool y 1098b1da1e71SJan Beulich depends on X86_LOCAL_APIC || X86_UP_IOAPIC 1099506f1d07SSam Ravnborg 110041b9eb26SStefan Assmannconfig X86_REROUTE_FOR_BROKEN_BOOT_IRQS 110141b9eb26SStefan Assmann bool "Reroute for broken boot IRQs" 110241b9eb26SStefan Assmann depends on X86_IO_APIC 1103a7f7f624SMasahiro Yamada help 110441b9eb26SStefan Assmann This option enables a workaround that fixes a source of 110541b9eb26SStefan Assmann spurious interrupts. This is recommended when threaded 110641b9eb26SStefan Assmann interrupt handling is used on systems where the generation of 110741b9eb26SStefan Assmann superfluous "boot interrupts" cannot be disabled. 110841b9eb26SStefan Assmann 110941b9eb26SStefan Assmann Some chipsets generate a legacy INTx "boot IRQ" when the IRQ 111041b9eb26SStefan Assmann entry in the chipset's IO-APIC is masked (as, e.g. the RT 111141b9eb26SStefan Assmann kernel does during interrupt handling). On chipsets where this 111241b9eb26SStefan Assmann boot IRQ generation cannot be disabled, this workaround keeps 111341b9eb26SStefan Assmann the original IRQ line masked so that only the equivalent "boot 111441b9eb26SStefan Assmann IRQ" is delivered to the CPUs. The workaround also tells the 111541b9eb26SStefan Assmann kernel to set up the IRQ handler on the boot IRQ line. In this 111641b9eb26SStefan Assmann way only one interrupt is delivered to the kernel. Otherwise 111741b9eb26SStefan Assmann the spurious second interrupt may cause the kernel to bring 111841b9eb26SStefan Assmann down (vital) interrupt lines. 111941b9eb26SStefan Assmann 112041b9eb26SStefan Assmann Only affects "broken" chipsets. Interrupt sharing may be 112141b9eb26SStefan Assmann increased on these systems. 112241b9eb26SStefan Assmann 1123506f1d07SSam Ravnborgconfig X86_MCE 1124bab9bc65SAndi Kleen bool "Machine Check / overheating reporting" 1125648ed940SChen, Gong select GENERIC_ALLOCATOR 1126e57dbaf7SBorislav Petkov default y 1127a7f7f624SMasahiro Yamada help 1128bab9bc65SAndi Kleen Machine Check support allows the processor to notify the 1129bab9bc65SAndi Kleen kernel if it detects a problem (e.g. overheating, data corruption). 1130506f1d07SSam Ravnborg The action the kernel takes depends on the severity of the problem, 1131bab9bc65SAndi Kleen ranging from warning messages to halting the machine. 11324efc0670SAndi Kleen 11335de97c9fSTony Luckconfig X86_MCELOG_LEGACY 11345de97c9fSTony Luck bool "Support for deprecated /dev/mcelog character device" 11355de97c9fSTony Luck depends on X86_MCE 1136a7f7f624SMasahiro Yamada help 11375de97c9fSTony Luck Enable support for /dev/mcelog which is needed by the old mcelog 11385de97c9fSTony Luck userspace logging daemon. Consider switching to the new generation 11395de97c9fSTony Luck rasdaemon solution. 11405de97c9fSTony Luck 1141506f1d07SSam Ravnborgconfig X86_MCE_INTEL 11423c2362e6SHarvey Harrison def_bool y 11433c2362e6SHarvey Harrison prompt "Intel MCE features" 1144c1ebf835SAndi Kleen depends on X86_MCE && X86_LOCAL_APIC 1145a7f7f624SMasahiro Yamada help 1146506f1d07SSam Ravnborg Additional support for intel specific MCE features such as 1147506f1d07SSam Ravnborg the thermal monitor. 1148506f1d07SSam Ravnborg 1149506f1d07SSam Ravnborgconfig X86_MCE_AMD 11503c2362e6SHarvey Harrison def_bool y 11513c2362e6SHarvey Harrison prompt "AMD MCE features" 1152f5382de9SYazen Ghannam depends on X86_MCE && X86_LOCAL_APIC && AMD_NB 1153a7f7f624SMasahiro Yamada help 1154506f1d07SSam Ravnborg Additional support for AMD specific MCE features such as 1155506f1d07SSam Ravnborg the DRAM Error Threshold. 1156506f1d07SSam Ravnborg 11574efc0670SAndi Kleenconfig X86_ANCIENT_MCE 11586fc108a0SJan Beulich bool "Support for old Pentium 5 / WinChip machine checks" 1159c31d9633SAndi Kleen depends on X86_32 && X86_MCE 1160a7f7f624SMasahiro Yamada help 11614efc0670SAndi Kleen Include support for machine check handling on old Pentium 5 or WinChip 11625065a706SMasanari Iida systems. These typically need to be enabled explicitly on the command 11634efc0670SAndi Kleen line. 11644efc0670SAndi Kleen 1165b2762686SAndi Kleenconfig X86_MCE_THRESHOLD 1166b2762686SAndi Kleen depends on X86_MCE_AMD || X86_MCE_INTEL 11676fc108a0SJan Beulich def_bool y 1168b2762686SAndi Kleen 1169ea149b36SAndi Kleenconfig X86_MCE_INJECT 1170bc8e80d5SBorislav Petkov depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS 1171ea149b36SAndi Kleen tristate "Machine check injector support" 1172a7f7f624SMasahiro Yamada help 1173ea149b36SAndi Kleen Provide support for injecting machine checks for testing purposes. 1174ea149b36SAndi Kleen If you don't know what a machine check is and you don't do kernel 1175ea149b36SAndi Kleen QA it is safe to say n. 1176ea149b36SAndi Kleen 117707dc900eSPeter Zijlstrasource "arch/x86/events/Kconfig" 1178e633c65aSKan Liang 11795aef51c3SAndy Lutomirskiconfig X86_LEGACY_VM86 11801e642812SIngo Molnar bool "Legacy VM86 support" 1181506f1d07SSam Ravnborg depends on X86_32 1182a7f7f624SMasahiro Yamada help 11835aef51c3SAndy Lutomirski This option allows user programs to put the CPU into V8086 11845aef51c3SAndy Lutomirski mode, which is an 80286-era approximation of 16-bit real mode. 11855aef51c3SAndy Lutomirski 11865aef51c3SAndy Lutomirski Some very old versions of X and/or vbetool require this option 11875aef51c3SAndy Lutomirski for user mode setting. Similarly, DOSEMU will use it if 11885aef51c3SAndy Lutomirski available to accelerate real mode DOS programs. However, any 11895aef51c3SAndy Lutomirski recent version of DOSEMU, X, or vbetool should be fully 11905aef51c3SAndy Lutomirski functional even without kernel VM86 support, as they will all 11911e642812SIngo Molnar fall back to software emulation. Nevertheless, if you are using 11921e642812SIngo Molnar a 16-bit DOS program where 16-bit performance matters, vm86 11931e642812SIngo Molnar mode might be faster than emulation and you might want to 11941e642812SIngo Molnar enable this option. 11955aef51c3SAndy Lutomirski 11961e642812SIngo Molnar Note that any app that works on a 64-bit kernel is unlikely to 11971e642812SIngo Molnar need this option, as 64-bit kernels don't, and can't, support 11981e642812SIngo Molnar V8086 mode. This option is also unrelated to 16-bit protected 11991e642812SIngo Molnar mode and is not needed to run most 16-bit programs under Wine. 12005aef51c3SAndy Lutomirski 12011e642812SIngo Molnar Enabling this option increases the complexity of the kernel 12021e642812SIngo Molnar and slows down exception handling a tiny bit. 12035aef51c3SAndy Lutomirski 12041e642812SIngo Molnar If unsure, say N here. 12055aef51c3SAndy Lutomirski 12065aef51c3SAndy Lutomirskiconfig VM86 12075aef51c3SAndy Lutomirski bool 12085aef51c3SAndy Lutomirski default X86_LEGACY_VM86 120934273f41SH. Peter Anvin 121034273f41SH. Peter Anvinconfig X86_16BIT 121134273f41SH. Peter Anvin bool "Enable support for 16-bit segments" if EXPERT 121234273f41SH. Peter Anvin default y 1213a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 1214a7f7f624SMasahiro Yamada help 121534273f41SH. Peter Anvin This option is required by programs like Wine to run 16-bit 121634273f41SH. Peter Anvin protected mode legacy code on x86 processors. Disabling 121734273f41SH. Peter Anvin this option saves about 300 bytes on i386, or around 6K text 121834273f41SH. Peter Anvin plus 16K runtime memory on x86-64, 121934273f41SH. Peter Anvin 122034273f41SH. Peter Anvinconfig X86_ESPFIX32 122134273f41SH. Peter Anvin def_bool y 122234273f41SH. Peter Anvin depends on X86_16BIT && X86_32 1223506f1d07SSam Ravnborg 1224197725deSH. Peter Anvinconfig X86_ESPFIX64 1225197725deSH. Peter Anvin def_bool y 122634273f41SH. Peter Anvin depends on X86_16BIT && X86_64 1227506f1d07SSam Ravnborg 12281ad83c85SAndy Lutomirskiconfig X86_VSYSCALL_EMULATION 12291ad83c85SAndy Lutomirski bool "Enable vsyscall emulation" if EXPERT 12301ad83c85SAndy Lutomirski default y 12311ad83c85SAndy Lutomirski depends on X86_64 1232a7f7f624SMasahiro Yamada help 12331ad83c85SAndy Lutomirski This enables emulation of the legacy vsyscall page. Disabling 12341ad83c85SAndy Lutomirski it is roughly equivalent to booting with vsyscall=none, except 12351ad83c85SAndy Lutomirski that it will also disable the helpful warning if a program 12361ad83c85SAndy Lutomirski tries to use a vsyscall. With this option set to N, offending 12371ad83c85SAndy Lutomirski programs will just segfault, citing addresses of the form 12381ad83c85SAndy Lutomirski 0xffffffffff600?00. 12391ad83c85SAndy Lutomirski 12401ad83c85SAndy Lutomirski This option is required by many programs built before 2013, and 12411ad83c85SAndy Lutomirski care should be used even with newer programs if set to N. 12421ad83c85SAndy Lutomirski 12431ad83c85SAndy Lutomirski Disabling this option saves about 7K of kernel size and 12441ad83c85SAndy Lutomirski possibly 4K of additional runtime pagetable memory. 12451ad83c85SAndy Lutomirski 1246111e7b15SThomas Gleixnerconfig X86_IOPL_IOPERM 1247111e7b15SThomas Gleixner bool "IOPERM and IOPL Emulation" 1248a24ca997SThomas Gleixner default y 1249a7f7f624SMasahiro Yamada help 1250111e7b15SThomas Gleixner This enables the ioperm() and iopl() syscalls which are necessary 1251111e7b15SThomas Gleixner for legacy applications. 1252111e7b15SThomas Gleixner 1253c8137aceSThomas Gleixner Legacy IOPL support is an overbroad mechanism which allows user 1254c8137aceSThomas Gleixner space aside of accessing all 65536 I/O ports also to disable 1255c8137aceSThomas Gleixner interrupts. To gain this access the caller needs CAP_SYS_RAWIO 1256c8137aceSThomas Gleixner capabilities and permission from potentially active security 1257c8137aceSThomas Gleixner modules. 1258c8137aceSThomas Gleixner 1259c8137aceSThomas Gleixner The emulation restricts the functionality of the syscall to 1260c8137aceSThomas Gleixner only allowing the full range I/O port access, but prevents the 1261a24ca997SThomas Gleixner ability to disable interrupts from user space which would be 1262a24ca997SThomas Gleixner granted if the hardware IOPL mechanism would be used. 1263c8137aceSThomas Gleixner 1264506f1d07SSam Ravnborgconfig TOSHIBA 1265506f1d07SSam Ravnborg tristate "Toshiba Laptop support" 1266506f1d07SSam Ravnborg depends on X86_32 1267a7f7f624SMasahiro Yamada help 1268506f1d07SSam Ravnborg This adds a driver to safely access the System Management Mode of 1269506f1d07SSam Ravnborg the CPU on Toshiba portables with a genuine Toshiba BIOS. It does 1270506f1d07SSam Ravnborg not work on models with a Phoenix BIOS. The System Management Mode 1271506f1d07SSam Ravnborg is used to set the BIOS and power saving options on Toshiba portables. 1272506f1d07SSam Ravnborg 1273506f1d07SSam Ravnborg For information on utilities to make use of this driver see the 1274506f1d07SSam Ravnborg Toshiba Linux utilities web site at: 1275506f1d07SSam Ravnborg <http://www.buzzard.org.uk/toshiba/>. 1276506f1d07SSam Ravnborg 1277506f1d07SSam Ravnborg Say Y if you intend to run this kernel on a Toshiba portable. 1278506f1d07SSam Ravnborg Say N otherwise. 1279506f1d07SSam Ravnborg 1280506f1d07SSam Ravnborgconfig X86_REBOOTFIXUPS 12819ba16087SJan Beulich bool "Enable X86 board specific fixups for reboot" 12829ba16087SJan Beulich depends on X86_32 1283a7f7f624SMasahiro Yamada help 1284506f1d07SSam Ravnborg This enables chipset and/or board specific fixups to be done 1285506f1d07SSam Ravnborg in order to get reboot to work correctly. This is only needed on 1286506f1d07SSam Ravnborg some combinations of hardware and BIOS. The symptom, for which 1287506f1d07SSam Ravnborg this config is intended, is when reboot ends with a stalled/hung 1288506f1d07SSam Ravnborg system. 1289506f1d07SSam Ravnborg 1290506f1d07SSam Ravnborg Currently, the only fixup is for the Geode machines using 12915e3a77e9SFlorian Fainelli CS5530A and CS5536 chipsets and the RDC R-321x SoC. 1292506f1d07SSam Ravnborg 1293506f1d07SSam Ravnborg Say Y if you want to enable the fixup. Currently, it's safe to 1294506f1d07SSam Ravnborg enable this option even if you don't need it. 1295506f1d07SSam Ravnborg Say N otherwise. 1296506f1d07SSam Ravnborg 1297506f1d07SSam Ravnborgconfig MICROCODE 12989a2bc335SBorislav Petkov bool "CPU microcode loading support" 12999a2bc335SBorislav Petkov default y 130080030e3dSBorislav Petkov depends on CPU_SUP_AMD || CPU_SUP_INTEL 1301a7f7f624SMasahiro Yamada help 1302506f1d07SSam Ravnborg If you say Y here, you will be able to update the microcode on 13035f9c01aaSBorislav Petkov Intel and AMD processors. The Intel support is for the IA32 family, 13045f9c01aaSBorislav Petkov e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The 13055f9c01aaSBorislav Petkov AMD support is for families 0x10 and later. You will obviously need 13065f9c01aaSBorislav Petkov the actual microcode binary data itself which is not shipped with 13075f9c01aaSBorislav Petkov the Linux kernel. 1308506f1d07SSam Ravnborg 13095f9c01aaSBorislav Petkov The preferred method to load microcode from a detached initrd is described 1310cb1aaebeSMauro Carvalho Chehab in Documentation/x86/microcode.rst. For that you need to enable 13115f9c01aaSBorislav Petkov CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the 13125f9c01aaSBorislav Petkov initrd for microcode blobs. 1313506f1d07SSam Ravnborg 1314c508c46eSBenjamin Gilbert In addition, you can build the microcode into the kernel. For that you 1315c508c46eSBenjamin Gilbert need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE 1316c508c46eSBenjamin Gilbert config option. 1317506f1d07SSam Ravnborg 13188d86f390SPeter Orubaconfig MICROCODE_INTEL 1319e43f6e67SBorislav Petkov bool "Intel microcode loading support" 13208d86f390SPeter Oruba depends on MICROCODE 13218d86f390SPeter Oruba default MICROCODE 1322a7f7f624SMasahiro Yamada help 13238d86f390SPeter Oruba This options enables microcode patch loading support for Intel 13248d86f390SPeter Oruba processors. 13258d86f390SPeter Oruba 1326b8989db9SAlan For the current Intel microcode data package go to 1327b8989db9SAlan <https://downloadcenter.intel.com> and search for 1328b8989db9SAlan 'Linux Processor Microcode Data File'. 13298d86f390SPeter Oruba 133080cc9f10SPeter Orubaconfig MICROCODE_AMD 1331e43f6e67SBorislav Petkov bool "AMD microcode loading support" 133280cc9f10SPeter Oruba depends on MICROCODE 1333a7f7f624SMasahiro Yamada help 133480cc9f10SPeter Oruba If you select this option, microcode patch loading support for AMD 133580cc9f10SPeter Oruba processors will be enabled. 133680cc9f10SPeter Oruba 1337506f1d07SSam Ravnborgconfig MICROCODE_OLD_INTERFACE 1338c02f48e0SBorislav Petkov bool "Ancient loading interface (DEPRECATED)" 1339c02f48e0SBorislav Petkov default n 1340506f1d07SSam Ravnborg depends on MICROCODE 1341a7f7f624SMasahiro Yamada help 1342c02f48e0SBorislav Petkov DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface 1343c02f48e0SBorislav Petkov which was used by userspace tools like iucode_tool and microcode.ctl. 1344c02f48e0SBorislav Petkov It is inadequate because it runs too late to be able to properly 1345c02f48e0SBorislav Petkov load microcode on a machine and it needs special tools. Instead, you 1346c02f48e0SBorislav Petkov should've switched to the early loading method with the initrd or 1347cb1aaebeSMauro Carvalho Chehab builtin microcode by now: Documentation/x86/microcode.rst 1348506f1d07SSam Ravnborg 1349506f1d07SSam Ravnborgconfig X86_MSR 1350506f1d07SSam Ravnborg tristate "/dev/cpu/*/msr - Model-specific register support" 1351a7f7f624SMasahiro Yamada help 1352506f1d07SSam Ravnborg This device gives privileged processes access to the x86 1353506f1d07SSam Ravnborg Model-Specific Registers (MSRs). It is a character device with 1354506f1d07SSam Ravnborg major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr. 1355506f1d07SSam Ravnborg MSR accesses are directed to a specific CPU on multi-processor 1356506f1d07SSam Ravnborg systems. 1357506f1d07SSam Ravnborg 1358506f1d07SSam Ravnborgconfig X86_CPUID 1359506f1d07SSam Ravnborg tristate "/dev/cpu/*/cpuid - CPU information support" 1360a7f7f624SMasahiro Yamada help 1361506f1d07SSam Ravnborg This device gives processes access to the x86 CPUID instruction to 1362506f1d07SSam Ravnborg be executed on a specific processor. It is a character device 1363506f1d07SSam Ravnborg with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to 1364506f1d07SSam Ravnborg /dev/cpu/31/cpuid. 1365506f1d07SSam Ravnborg 1366506f1d07SSam Ravnborgchoice 1367506f1d07SSam Ravnborg prompt "High Memory Support" 13686fc108a0SJan Beulich default HIGHMEM4G 1369506f1d07SSam Ravnborg depends on X86_32 1370506f1d07SSam Ravnborg 1371506f1d07SSam Ravnborgconfig NOHIGHMEM 1372506f1d07SSam Ravnborg bool "off" 1373a7f7f624SMasahiro Yamada help 1374506f1d07SSam Ravnborg Linux can use up to 64 Gigabytes of physical memory on x86 systems. 1375506f1d07SSam Ravnborg However, the address space of 32-bit x86 processors is only 4 1376506f1d07SSam Ravnborg Gigabytes large. That means that, if you have a large amount of 1377506f1d07SSam Ravnborg physical memory, not all of it can be "permanently mapped" by the 1378506f1d07SSam Ravnborg kernel. The physical memory that's not permanently mapped is called 1379506f1d07SSam Ravnborg "high memory". 1380506f1d07SSam Ravnborg 1381506f1d07SSam Ravnborg If you are compiling a kernel which will never run on a machine with 1382506f1d07SSam Ravnborg more than 1 Gigabyte total physical RAM, answer "off" here (default 1383506f1d07SSam Ravnborg choice and suitable for most users). This will result in a "3GB/1GB" 1384506f1d07SSam Ravnborg split: 3GB are mapped so that each process sees a 3GB virtual memory 1385506f1d07SSam Ravnborg space and the remaining part of the 4GB virtual memory space is used 1386506f1d07SSam Ravnborg by the kernel to permanently map as much physical memory as 1387506f1d07SSam Ravnborg possible. 1388506f1d07SSam Ravnborg 1389506f1d07SSam Ravnborg If the machine has between 1 and 4 Gigabytes physical RAM, then 1390506f1d07SSam Ravnborg answer "4GB" here. 1391506f1d07SSam Ravnborg 1392506f1d07SSam Ravnborg If more than 4 Gigabytes is used then answer "64GB" here. This 1393506f1d07SSam Ravnborg selection turns Intel PAE (Physical Address Extension) mode on. 1394506f1d07SSam Ravnborg PAE implements 3-level paging on IA32 processors. PAE is fully 1395506f1d07SSam Ravnborg supported by Linux, PAE mode is implemented on all recent Intel 1396506f1d07SSam Ravnborg processors (Pentium Pro and better). NOTE: If you say "64GB" here, 1397506f1d07SSam Ravnborg then the kernel will not boot on CPUs that don't support PAE! 1398506f1d07SSam Ravnborg 1399506f1d07SSam Ravnborg The actual amount of total physical memory will either be 1400506f1d07SSam Ravnborg auto detected or can be forced by using a kernel command line option 1401506f1d07SSam Ravnborg such as "mem=256M". (Try "man bootparam" or see the documentation of 1402506f1d07SSam Ravnborg your boot loader (lilo or loadlin) about how to pass options to the 1403506f1d07SSam Ravnborg kernel at boot time.) 1404506f1d07SSam Ravnborg 1405506f1d07SSam Ravnborg If unsure, say "off". 1406506f1d07SSam Ravnborg 1407506f1d07SSam Ravnborgconfig HIGHMEM4G 1408506f1d07SSam Ravnborg bool "4GB" 1409a7f7f624SMasahiro Yamada help 1410506f1d07SSam Ravnborg Select this if you have a 32-bit processor and between 1 and 4 1411506f1d07SSam Ravnborg gigabytes of physical RAM. 1412506f1d07SSam Ravnborg 1413506f1d07SSam Ravnborgconfig HIGHMEM64G 1414506f1d07SSam Ravnborg bool "64GB" 1415225bac2dSLukas Bulwahn depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6 1416506f1d07SSam Ravnborg select X86_PAE 1417a7f7f624SMasahiro Yamada help 1418506f1d07SSam Ravnborg Select this if you have a 32-bit processor and more than 4 1419506f1d07SSam Ravnborg gigabytes of physical RAM. 1420506f1d07SSam Ravnborg 1421506f1d07SSam Ravnborgendchoice 1422506f1d07SSam Ravnborg 1423506f1d07SSam Ravnborgchoice 14246a108a14SDavid Rientjes prompt "Memory split" if EXPERT 1425506f1d07SSam Ravnborg default VMSPLIT_3G 1426506f1d07SSam Ravnborg depends on X86_32 1427a7f7f624SMasahiro Yamada help 1428506f1d07SSam Ravnborg Select the desired split between kernel and user memory. 1429506f1d07SSam Ravnborg 1430506f1d07SSam Ravnborg If the address range available to the kernel is less than the 1431506f1d07SSam Ravnborg physical memory installed, the remaining memory will be available 1432506f1d07SSam Ravnborg as "high memory". Accessing high memory is a little more costly 1433506f1d07SSam Ravnborg than low memory, as it needs to be mapped into the kernel first. 1434506f1d07SSam Ravnborg Note that increasing the kernel address space limits the range 1435506f1d07SSam Ravnborg available to user programs, making the address space there 1436506f1d07SSam Ravnborg tighter. Selecting anything other than the default 3G/1G split 1437506f1d07SSam Ravnborg will also likely make your kernel incompatible with binary-only 1438506f1d07SSam Ravnborg kernel modules. 1439506f1d07SSam Ravnborg 1440506f1d07SSam Ravnborg If you are not absolutely sure what you are doing, leave this 1441506f1d07SSam Ravnborg option alone! 1442506f1d07SSam Ravnborg 1443506f1d07SSam Ravnborg config VMSPLIT_3G 1444506f1d07SSam Ravnborg bool "3G/1G user/kernel split" 1445506f1d07SSam Ravnborg config VMSPLIT_3G_OPT 1446506f1d07SSam Ravnborg depends on !X86_PAE 1447506f1d07SSam Ravnborg bool "3G/1G user/kernel split (for full 1G low memory)" 1448506f1d07SSam Ravnborg config VMSPLIT_2G 1449506f1d07SSam Ravnborg bool "2G/2G user/kernel split" 1450506f1d07SSam Ravnborg config VMSPLIT_2G_OPT 1451506f1d07SSam Ravnborg depends on !X86_PAE 1452506f1d07SSam Ravnborg bool "2G/2G user/kernel split (for full 2G low memory)" 1453506f1d07SSam Ravnborg config VMSPLIT_1G 1454506f1d07SSam Ravnborg bool "1G/3G user/kernel split" 1455506f1d07SSam Ravnborgendchoice 1456506f1d07SSam Ravnborg 1457506f1d07SSam Ravnborgconfig PAGE_OFFSET 1458506f1d07SSam Ravnborg hex 1459506f1d07SSam Ravnborg default 0xB0000000 if VMSPLIT_3G_OPT 1460506f1d07SSam Ravnborg default 0x80000000 if VMSPLIT_2G 1461506f1d07SSam Ravnborg default 0x78000000 if VMSPLIT_2G_OPT 1462506f1d07SSam Ravnborg default 0x40000000 if VMSPLIT_1G 1463506f1d07SSam Ravnborg default 0xC0000000 1464506f1d07SSam Ravnborg depends on X86_32 1465506f1d07SSam Ravnborg 1466506f1d07SSam Ravnborgconfig HIGHMEM 14673c2362e6SHarvey Harrison def_bool y 1468506f1d07SSam Ravnborg depends on X86_32 && (HIGHMEM64G || HIGHMEM4G) 1469506f1d07SSam Ravnborg 1470506f1d07SSam Ravnborgconfig X86_PAE 14719ba16087SJan Beulich bool "PAE (Physical Address Extension) Support" 1472506f1d07SSam Ravnborg depends on X86_32 && !HIGHMEM4G 1473d4a451d5SChristoph Hellwig select PHYS_ADDR_T_64BIT 14749d99c712SChristian Melki select SWIOTLB 1475a7f7f624SMasahiro Yamada help 1476506f1d07SSam Ravnborg PAE is required for NX support, and furthermore enables 1477506f1d07SSam Ravnborg larger swapspace support for non-overcommit purposes. It 1478506f1d07SSam Ravnborg has the cost of more pagetable lookup overhead, and also 1479506f1d07SSam Ravnborg consumes more pagetable space per process. 1480506f1d07SSam Ravnborg 148177ef56e4SKirill A. Shutemovconfig X86_5LEVEL 148277ef56e4SKirill A. Shutemov bool "Enable 5-level page tables support" 148318ec1eafSKirill A. Shutemov default y 1484eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 1485162434e7SKirill A. Shutemov select SPARSEMEM_VMEMMAP 148677ef56e4SKirill A. Shutemov depends on X86_64 1487a7f7f624SMasahiro Yamada help 148877ef56e4SKirill A. Shutemov 5-level paging enables access to larger address space: 148977ef56e4SKirill A. Shutemov upto 128 PiB of virtual address space and 4 PiB of 149077ef56e4SKirill A. Shutemov physical address space. 149177ef56e4SKirill A. Shutemov 149277ef56e4SKirill A. Shutemov It will be supported by future Intel CPUs. 149377ef56e4SKirill A. Shutemov 14946657fca0SKirill A. Shutemov A kernel with the option enabled can be booted on machines that 14956657fca0SKirill A. Shutemov support 4- or 5-level paging. 149677ef56e4SKirill A. Shutemov 1497cb1aaebeSMauro Carvalho Chehab See Documentation/x86/x86_64/5level-paging.rst for more 149877ef56e4SKirill A. Shutemov information. 149977ef56e4SKirill A. Shutemov 150077ef56e4SKirill A. Shutemov Say N if unsure. 150177ef56e4SKirill A. Shutemov 150210971ab2SIngo Molnarconfig X86_DIRECT_GBPAGES 1503e5008abeSLuis R. Rodriguez def_bool y 15042e1da13fSVlastimil Babka depends on X86_64 1505a7f7f624SMasahiro Yamada help 150610971ab2SIngo Molnar Certain kernel features effectively disable kernel 150710971ab2SIngo Molnar linear 1 GB mappings (even if the CPU otherwise 150810971ab2SIngo Molnar supports them), so don't confuse the user by printing 150910971ab2SIngo Molnar that we have them enabled. 15109e899816SNick Piggin 15115c280cf6SThomas Gleixnerconfig X86_CPA_STATISTICS 15125c280cf6SThomas Gleixner bool "Enable statistic for Change Page Attribute" 15135c280cf6SThomas Gleixner depends on DEBUG_FS 1514a7f7f624SMasahiro Yamada help 1515b75baaf3SIngo Molnar Expose statistics about the Change Page Attribute mechanism, which 1516a943245aSColin Ian King helps to determine the effectiveness of preserving large and huge 15175c280cf6SThomas Gleixner page mappings when mapping protections are changed. 15185c280cf6SThomas Gleixner 151920f07a04SKirill A. Shutemovconfig X86_MEM_ENCRYPT 152020f07a04SKirill A. Shutemov select ARCH_HAS_FORCE_DMA_UNENCRYPTED 152120f07a04SKirill A. Shutemov select DYNAMIC_PHYSICAL_MASK 152220f07a04SKirill A. Shutemov select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS 152320f07a04SKirill A. Shutemov def_bool n 152420f07a04SKirill A. Shutemov 15257744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT 15267744ccdbSTom Lendacky bool "AMD Secure Memory Encryption (SME) support" 15277744ccdbSTom Lendacky depends on X86_64 && CPU_SUP_AMD 152882fef0adSDavid Rientjes select DMA_COHERENT_POOL 1529ce9084baSArd Biesheuvel select ARCH_USE_MEMREMAP_PROT 1530597cfe48SJoerg Roedel select INSTRUCTION_DECODER 1531aa5a4611STom Lendacky select ARCH_HAS_CC_PLATFORM 153220f07a04SKirill A. Shutemov select X86_MEM_ENCRYPT 1533a7f7f624SMasahiro Yamada help 15347744ccdbSTom Lendacky Say yes to enable support for the encryption of system memory. 15357744ccdbSTom Lendacky This requires an AMD processor that supports Secure Memory 15367744ccdbSTom Lendacky Encryption (SME). 15377744ccdbSTom Lendacky 15387744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 15397744ccdbSTom Lendacky bool "Activate AMD Secure Memory Encryption (SME) by default" 15407744ccdbSTom Lendacky depends on AMD_MEM_ENCRYPT 1541a7f7f624SMasahiro Yamada help 15427744ccdbSTom Lendacky Say yes to have system memory encrypted by default if running on 15437744ccdbSTom Lendacky an AMD processor that supports Secure Memory Encryption (SME). 15447744ccdbSTom Lendacky 15457744ccdbSTom Lendacky If set to Y, then the encryption of system memory can be 15467744ccdbSTom Lendacky deactivated with the mem_encrypt=off command line option. 15477744ccdbSTom Lendacky 15487744ccdbSTom Lendacky If set to N, then the encryption of system memory can be 15497744ccdbSTom Lendacky activated with the mem_encrypt=on command line option. 15507744ccdbSTom Lendacky 1551506f1d07SSam Ravnborg# Common NUMA Features 1552506f1d07SSam Ravnborgconfig NUMA 1553e133f6eaSRandy Dunlap bool "NUMA Memory Allocation and Scheduler Support" 1554506f1d07SSam Ravnborg depends on SMP 1555b5660ba7SH. Peter Anvin depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) 1556b5660ba7SH. Peter Anvin default y if X86_BIGSMP 15577ecd19cfSKefeng Wang select USE_PERCPU_NUMA_NODE_ID 1558a7f7f624SMasahiro Yamada help 1559e133f6eaSRandy Dunlap Enable NUMA (Non-Uniform Memory Access) support. 1560fd51b2d7SKOSAKI Motohiro 1561506f1d07SSam Ravnborg The kernel will try to allocate memory used by a CPU on the 1562506f1d07SSam Ravnborg local memory controller of the CPU and add some more 1563506f1d07SSam Ravnborg NUMA awareness to the kernel. 1564506f1d07SSam Ravnborg 1565c280ea5eSIngo Molnar For 64-bit this is recommended if the system is Intel Core i7 1566fd51b2d7SKOSAKI Motohiro (or later), AMD Opteron, or EM64T NUMA. 1567fd51b2d7SKOSAKI Motohiro 1568b5660ba7SH. Peter Anvin For 32-bit this is only needed if you boot a 32-bit 15697cf6c945SDavid Rientjes kernel on a 64-bit NUMA platform. 1570fd51b2d7SKOSAKI Motohiro 1571fd51b2d7SKOSAKI Motohiro Otherwise, you should say N. 1572506f1d07SSam Ravnborg 1573eec1d4faSHans Rosenfeldconfig AMD_NUMA 15743c2362e6SHarvey Harrison def_bool y 15753c2362e6SHarvey Harrison prompt "Old style AMD Opteron NUMA detection" 15765da0ef9aSTejun Heo depends on X86_64 && NUMA && PCI 1577a7f7f624SMasahiro Yamada help 1578eec1d4faSHans Rosenfeld Enable AMD NUMA node topology detection. You should say Y here if 1579eec1d4faSHans Rosenfeld you have a multi processor AMD system. This uses an old method to 1580eec1d4faSHans Rosenfeld read the NUMA configuration directly from the builtin Northbridge 1581eec1d4faSHans Rosenfeld of Opteron. It is recommended to use X86_64_ACPI_NUMA instead, 1582eec1d4faSHans Rosenfeld which also takes priority if both are compiled in. 1583506f1d07SSam Ravnborg 1584506f1d07SSam Ravnborgconfig X86_64_ACPI_NUMA 15853c2362e6SHarvey Harrison def_bool y 15863c2362e6SHarvey Harrison prompt "ACPI NUMA detection" 1587506f1d07SSam Ravnborg depends on X86_64 && NUMA && ACPI && PCI 1588506f1d07SSam Ravnborg select ACPI_NUMA 1589a7f7f624SMasahiro Yamada help 1590506f1d07SSam Ravnborg Enable ACPI SRAT based node topology detection. 1591506f1d07SSam Ravnborg 1592506f1d07SSam Ravnborgconfig NUMA_EMU 1593506f1d07SSam Ravnborg bool "NUMA emulation" 15941b7e03efSTejun Heo depends on NUMA 1595a7f7f624SMasahiro Yamada help 1596506f1d07SSam Ravnborg Enable NUMA emulation. A flat machine will be split 1597506f1d07SSam Ravnborg into virtual nodes when booted with "numa=fake=N", where N is the 1598506f1d07SSam Ravnborg number of nodes. This is only useful for debugging. 1599506f1d07SSam Ravnborg 1600506f1d07SSam Ravnborgconfig NODES_SHIFT 1601d25e26b6SLinus Torvalds int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP 160251591e31SDavid Rientjes range 1 10 160351591e31SDavid Rientjes default "10" if MAXSMP 1604506f1d07SSam Ravnborg default "6" if X86_64 1605506f1d07SSam Ravnborg default "3" 1606a9ee6cf5SMike Rapoport depends on NUMA 1607a7f7f624SMasahiro Yamada help 16081184dc2fSMike Travis Specify the maximum number of NUMA Nodes available on the target 1609692105b8SMatt LaPlante system. Increases memory reserved to accommodate various tables. 1610506f1d07SSam Ravnborg 1611506f1d07SSam Ravnborgconfig ARCH_FLATMEM_ENABLE 1612506f1d07SSam Ravnborg def_bool y 16133b16651fSTejun Heo depends on X86_32 && !NUMA 1614506f1d07SSam Ravnborg 1615506f1d07SSam Ravnborgconfig ARCH_SPARSEMEM_ENABLE 1616506f1d07SSam Ravnborg def_bool y 16176ea30386SKees Cook depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD 1618506f1d07SSam Ravnborg select SPARSEMEM_STATIC if X86_32 1619506f1d07SSam Ravnborg select SPARSEMEM_VMEMMAP_ENABLE if X86_64 1620506f1d07SSam Ravnborg 16213b16651fSTejun Heoconfig ARCH_SPARSEMEM_DEFAULT 16226ad57f7fSMike Rapoport def_bool X86_64 || (NUMA && X86_32) 16233b16651fSTejun Heo 1624506f1d07SSam Ravnborgconfig ARCH_SELECT_MEMORY_MODEL 1625506f1d07SSam Ravnborg def_bool y 16264eda2bc3SDavid Hildenbrand depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE 1627506f1d07SSam Ravnborg 1628506f1d07SSam Ravnborgconfig ARCH_MEMORY_PROBE 1629a0842b70SToshi Kani bool "Enable sysfs memory/probe interface" 16305c11f00bSDavid Hildenbrand depends on MEMORY_HOTPLUG 1631a0842b70SToshi Kani help 1632a0842b70SToshi Kani This option enables a sysfs memory/probe interface for testing. 1633cb1aaebeSMauro Carvalho Chehab See Documentation/admin-guide/mm/memory-hotplug.rst for more information. 1634a0842b70SToshi Kani If you are unsure how to answer this question, answer N. 1635506f1d07SSam Ravnborg 16363b16651fSTejun Heoconfig ARCH_PROC_KCORE_TEXT 16373b16651fSTejun Heo def_bool y 16383b16651fSTejun Heo depends on X86_64 && PROC_KCORE 16393b16651fSTejun Heo 1640a29815a3SAvi Kivityconfig ILLEGAL_POINTER_VALUE 1641a29815a3SAvi Kivity hex 1642a29815a3SAvi Kivity default 0 if X86_32 1643a29815a3SAvi Kivity default 0xdead000000000000 if X86_64 1644a29815a3SAvi Kivity 16457a67832cSDan Williamsconfig X86_PMEM_LEGACY_DEVICE 16467a67832cSDan Williams bool 16477a67832cSDan Williams 1648ec776ef6SChristoph Hellwigconfig X86_PMEM_LEGACY 16497a67832cSDan Williams tristate "Support non-standard NVDIMMs and ADR protected memory" 16509f53f9faSDan Williams depends on PHYS_ADDR_T_64BIT 16519f53f9faSDan Williams depends on BLK_DEV 16527a67832cSDan Williams select X86_PMEM_LEGACY_DEVICE 16537b27a862SDan Williams select NUMA_KEEP_MEMINFO if NUMA 16549f53f9faSDan Williams select LIBNVDIMM 1655ec776ef6SChristoph Hellwig help 1656ec776ef6SChristoph Hellwig Treat memory marked using the non-standard e820 type of 12 as used 1657ec776ef6SChristoph Hellwig by the Intel Sandy Bridge-EP reference BIOS as protected memory. 1658ec776ef6SChristoph Hellwig The kernel will offer these regions to the 'pmem' driver so 1659ec776ef6SChristoph Hellwig they can be used for persistent storage. 1660ec776ef6SChristoph Hellwig 1661ec776ef6SChristoph Hellwig Say Y if unsure. 1662ec776ef6SChristoph Hellwig 1663506f1d07SSam Ravnborgconfig HIGHPTE 1664506f1d07SSam Ravnborg bool "Allocate 3rd-level pagetables from highmem" 16656fc108a0SJan Beulich depends on HIGHMEM 1666a7f7f624SMasahiro Yamada help 1667506f1d07SSam Ravnborg The VM uses one page table entry for each page of physical memory. 1668506f1d07SSam Ravnborg For systems with a lot of RAM, this can be wasteful of precious 1669506f1d07SSam Ravnborg low memory. Setting this option will put user-space page table 1670506f1d07SSam Ravnborg entries in high memory. 1671506f1d07SSam Ravnborg 16729f077871SJeremy Fitzhardingeconfig X86_CHECK_BIOS_CORRUPTION 16739f077871SJeremy Fitzhardinge bool "Check for low memory corruption" 1674a7f7f624SMasahiro Yamada help 16759f077871SJeremy Fitzhardinge Periodically check for memory corruption in low memory, which 16769f077871SJeremy Fitzhardinge is suspected to be caused by BIOS. Even when enabled in the 16779f077871SJeremy Fitzhardinge configuration, it is disabled at runtime. Enable it by 16789f077871SJeremy Fitzhardinge setting "memory_corruption_check=1" on the kernel command 16799f077871SJeremy Fitzhardinge line. By default it scans the low 64k of memory every 60 16809f077871SJeremy Fitzhardinge seconds; see the memory_corruption_check_size and 16819f077871SJeremy Fitzhardinge memory_corruption_check_period parameters in 16828c27ceffSMauro Carvalho Chehab Documentation/admin-guide/kernel-parameters.rst to adjust this. 16839f077871SJeremy Fitzhardinge 16849f077871SJeremy Fitzhardinge When enabled with the default parameters, this option has 16859f077871SJeremy Fitzhardinge almost no overhead, as it reserves a relatively small amount 16869f077871SJeremy Fitzhardinge of memory and scans it infrequently. It both detects corruption 16879f077871SJeremy Fitzhardinge and prevents it from affecting the running system. 16889f077871SJeremy Fitzhardinge 16899f077871SJeremy Fitzhardinge It is, however, intended as a diagnostic tool; if repeatable 16909f077871SJeremy Fitzhardinge BIOS-originated corruption always affects the same memory, 16919f077871SJeremy Fitzhardinge you can use memmap= to prevent the kernel from using that 16929f077871SJeremy Fitzhardinge memory. 16939f077871SJeremy Fitzhardinge 1694c885df50SJeremy Fitzhardingeconfig X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK 1695c885df50SJeremy Fitzhardinge bool "Set the default setting of memory_corruption_check" 1696c885df50SJeremy Fitzhardinge depends on X86_CHECK_BIOS_CORRUPTION 1697c885df50SJeremy Fitzhardinge default y 1698a7f7f624SMasahiro Yamada help 1699c885df50SJeremy Fitzhardinge Set whether the default state of memory_corruption_check is 1700c885df50SJeremy Fitzhardinge on or off. 1701c885df50SJeremy Fitzhardinge 1702506f1d07SSam Ravnborgconfig MATH_EMULATION 1703506f1d07SSam Ravnborg bool 1704a5b9e5a2SAndy Lutomirski depends on MODIFY_LDT_SYSCALL 170587d6021bSArnd Bergmann prompt "Math emulation" if X86_32 && (M486SX || MELAN) 1706a7f7f624SMasahiro Yamada help 1707506f1d07SSam Ravnborg Linux can emulate a math coprocessor (used for floating point 1708506f1d07SSam Ravnborg operations) if you don't have one. 486DX and Pentium processors have 1709506f1d07SSam Ravnborg a math coprocessor built in, 486SX and 386 do not, unless you added 1710506f1d07SSam Ravnborg a 487DX or 387, respectively. (The messages during boot time can 1711506f1d07SSam Ravnborg give you some hints here ["man dmesg"].) Everyone needs either a 1712506f1d07SSam Ravnborg coprocessor or this emulation. 1713506f1d07SSam Ravnborg 1714506f1d07SSam Ravnborg If you don't have a math coprocessor, you need to say Y here; if you 1715506f1d07SSam Ravnborg say Y here even though you have a coprocessor, the coprocessor will 1716506f1d07SSam Ravnborg be used nevertheless. (This behavior can be changed with the kernel 1717506f1d07SSam Ravnborg command line option "no387", which comes handy if your coprocessor 1718506f1d07SSam Ravnborg is broken. Try "man bootparam" or see the documentation of your boot 1719506f1d07SSam Ravnborg loader (lilo or loadlin) about how to pass options to the kernel at 1720506f1d07SSam Ravnborg boot time.) This means that it is a good idea to say Y here if you 1721506f1d07SSam Ravnborg intend to use this kernel on different machines. 1722506f1d07SSam Ravnborg 1723506f1d07SSam Ravnborg More information about the internals of the Linux math coprocessor 1724506f1d07SSam Ravnborg emulation can be found in <file:arch/x86/math-emu/README>. 1725506f1d07SSam Ravnborg 1726506f1d07SSam Ravnborg If you are not sure, say Y; apart from resulting in a 66 KB bigger 1727506f1d07SSam Ravnborg kernel, it won't hurt. 1728506f1d07SSam Ravnborg 1729506f1d07SSam Ravnborgconfig MTRR 17306fc108a0SJan Beulich def_bool y 17316a108a14SDavid Rientjes prompt "MTRR (Memory Type Range Register) support" if EXPERT 1732a7f7f624SMasahiro Yamada help 1733506f1d07SSam Ravnborg On Intel P6 family processors (Pentium Pro, Pentium II and later) 1734506f1d07SSam Ravnborg the Memory Type Range Registers (MTRRs) may be used to control 1735506f1d07SSam Ravnborg processor access to memory ranges. This is most useful if you have 1736506f1d07SSam Ravnborg a video (VGA) card on a PCI or AGP bus. Enabling write-combining 1737506f1d07SSam Ravnborg allows bus write transfers to be combined into a larger transfer 1738506f1d07SSam Ravnborg before bursting over the PCI/AGP bus. This can increase performance 1739506f1d07SSam Ravnborg of image write operations 2.5 times or more. Saying Y here creates a 1740506f1d07SSam Ravnborg /proc/mtrr file which may be used to manipulate your processor's 1741506f1d07SSam Ravnborg MTRRs. Typically the X server should use this. 1742506f1d07SSam Ravnborg 1743506f1d07SSam Ravnborg This code has a reasonably generic interface so that similar 1744506f1d07SSam Ravnborg control registers on other processors can be easily supported 1745506f1d07SSam Ravnborg as well: 1746506f1d07SSam Ravnborg 1747506f1d07SSam Ravnborg The Cyrix 6x86, 6x86MX and M II processors have Address Range 1748506f1d07SSam Ravnborg Registers (ARRs) which provide a similar functionality to MTRRs. For 1749506f1d07SSam Ravnborg these, the ARRs are used to emulate the MTRRs. 1750506f1d07SSam Ravnborg The AMD K6-2 (stepping 8 and above) and K6-3 processors have two 1751506f1d07SSam Ravnborg MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing 1752506f1d07SSam Ravnborg write-combining. All of these processors are supported by this code 1753506f1d07SSam Ravnborg and it makes sense to say Y here if you have one of them. 1754506f1d07SSam Ravnborg 1755506f1d07SSam Ravnborg Saying Y here also fixes a problem with buggy SMP BIOSes which only 1756506f1d07SSam Ravnborg set the MTRRs for the boot CPU and not for the secondary CPUs. This 1757506f1d07SSam Ravnborg can lead to all sorts of problems, so it's good to say Y here. 1758506f1d07SSam Ravnborg 1759506f1d07SSam Ravnborg You can safely say Y even if your machine doesn't have MTRRs, you'll 1760506f1d07SSam Ravnborg just add about 9 KB to your kernel. 1761506f1d07SSam Ravnborg 1762cb1aaebeSMauro Carvalho Chehab See <file:Documentation/x86/mtrr.rst> for more information. 1763506f1d07SSam Ravnborg 176495ffa243SYinghai Luconfig MTRR_SANITIZER 17652ffb3501SYinghai Lu def_bool y 176695ffa243SYinghai Lu prompt "MTRR cleanup support" 176795ffa243SYinghai Lu depends on MTRR 1768a7f7f624SMasahiro Yamada help 1769aba3728cSThomas Gleixner Convert MTRR layout from continuous to discrete, so X drivers can 1770aba3728cSThomas Gleixner add writeback entries. 177195ffa243SYinghai Lu 1772aba3728cSThomas Gleixner Can be disabled with disable_mtrr_cleanup on the kernel command line. 1773692105b8SMatt LaPlante The largest mtrr entry size for a continuous block can be set with 1774aba3728cSThomas Gleixner mtrr_chunk_size. 177595ffa243SYinghai Lu 17762ffb3501SYinghai Lu If unsure, say Y. 177795ffa243SYinghai Lu 177895ffa243SYinghai Luconfig MTRR_SANITIZER_ENABLE_DEFAULT 1779f5098d62SYinghai Lu int "MTRR cleanup enable value (0-1)" 1780f5098d62SYinghai Lu range 0 1 1781f5098d62SYinghai Lu default "0" 178295ffa243SYinghai Lu depends on MTRR_SANITIZER 1783a7f7f624SMasahiro Yamada help 1784f5098d62SYinghai Lu Enable mtrr cleanup default value 178595ffa243SYinghai Lu 178612031a62SYinghai Luconfig MTRR_SANITIZER_SPARE_REG_NR_DEFAULT 178712031a62SYinghai Lu int "MTRR cleanup spare reg num (0-7)" 178812031a62SYinghai Lu range 0 7 178912031a62SYinghai Lu default "1" 179012031a62SYinghai Lu depends on MTRR_SANITIZER 1791a7f7f624SMasahiro Yamada help 179212031a62SYinghai Lu mtrr cleanup spare entries default, it can be changed via 1793aba3728cSThomas Gleixner mtrr_spare_reg_nr=N on the kernel command line. 179412031a62SYinghai Lu 17952e5d9c85Svenkatesh.pallipadi@intel.comconfig X86_PAT 17966fc108a0SJan Beulich def_bool y 17976a108a14SDavid Rientjes prompt "x86 PAT support" if EXPERT 17982a8a2719SIngo Molnar depends on MTRR 1799a7f7f624SMasahiro Yamada help 18002e5d9c85Svenkatesh.pallipadi@intel.com Use PAT attributes to setup page level cache control. 1801042b78e4SVenki Pallipadi 18022e5d9c85Svenkatesh.pallipadi@intel.com PATs are the modern equivalents of MTRRs and are much more 18032e5d9c85Svenkatesh.pallipadi@intel.com flexible than MTRRs. 18042e5d9c85Svenkatesh.pallipadi@intel.com 18052e5d9c85Svenkatesh.pallipadi@intel.com Say N here if you see bootup problems (boot crash, boot hang, 1806042b78e4SVenki Pallipadi spontaneous reboots) or a non-working video driver. 18072e5d9c85Svenkatesh.pallipadi@intel.com 18082e5d9c85Svenkatesh.pallipadi@intel.com If unsure, say Y. 18092e5d9c85Svenkatesh.pallipadi@intel.com 181046cf98cdSVenkatesh Pallipadiconfig ARCH_USES_PG_UNCACHED 181146cf98cdSVenkatesh Pallipadi def_bool y 181246cf98cdSVenkatesh Pallipadi depends on X86_PAT 181346cf98cdSVenkatesh Pallipadi 1814628c6246SH. Peter Anvinconfig ARCH_RANDOM 1815628c6246SH. Peter Anvin def_bool y 1816628c6246SH. Peter Anvin prompt "x86 architectural random number generator" if EXPERT 1817a7f7f624SMasahiro Yamada help 1818628c6246SH. Peter Anvin Enable the x86 architectural RDRAND instruction 1819628c6246SH. Peter Anvin (Intel Bull Mountain technology) to generate random numbers. 1820628c6246SH. Peter Anvin If supported, this is a high bandwidth, cryptographically 1821628c6246SH. Peter Anvin secure hardware random number generator. 1822628c6246SH. Peter Anvin 182351ae4a2dSH. Peter Anvinconfig X86_SMAP 182451ae4a2dSH. Peter Anvin def_bool y 182551ae4a2dSH. Peter Anvin prompt "Supervisor Mode Access Prevention" if EXPERT 182603f16cd0SJosh Poimboeuf select OBJTOOL if HAVE_OBJTOOL 1827a7f7f624SMasahiro Yamada help 182851ae4a2dSH. Peter Anvin Supervisor Mode Access Prevention (SMAP) is a security 182951ae4a2dSH. Peter Anvin feature in newer Intel processors. There is a small 183051ae4a2dSH. Peter Anvin performance cost if this enabled and turned on; there is 183151ae4a2dSH. Peter Anvin also a small increase in the kernel size if this is enabled. 183251ae4a2dSH. Peter Anvin 183351ae4a2dSH. Peter Anvin If unsure, say Y. 183451ae4a2dSH. Peter Anvin 1835b971880fSBabu Mogerconfig X86_UMIP 1836796ebc81SRicardo Neri def_bool y 1837b971880fSBabu Moger prompt "User Mode Instruction Prevention" if EXPERT 1838a7f7f624SMasahiro Yamada help 1839b971880fSBabu Moger User Mode Instruction Prevention (UMIP) is a security feature in 1840b971880fSBabu Moger some x86 processors. If enabled, a general protection fault is 1841b971880fSBabu Moger issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are 1842b971880fSBabu Moger executed in user mode. These instructions unnecessarily expose 1843b971880fSBabu Moger information about the hardware state. 1844796ebc81SRicardo Neri 1845796ebc81SRicardo Neri The vast majority of applications do not use these instructions. 1846796ebc81SRicardo Neri For the very few that do, software emulation is provided in 1847796ebc81SRicardo Neri specific cases in protected and virtual-8086 modes. Emulated 1848796ebc81SRicardo Neri results are dummy. 1849aa35f896SRicardo Neri 1850156ff4a5SPeter Zijlstraconfig CC_HAS_IBT 1851156ff4a5SPeter Zijlstra # GCC >= 9 and binutils >= 2.29 1852156ff4a5SPeter Zijlstra # Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654 1853156ff4a5SPeter Zijlstra # Clang/LLVM >= 14 1854262448f3SNathan Chancellor # https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f 1855262448f3SNathan Chancellor # https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332 1856156ff4a5SPeter Zijlstra def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \ 1857262448f3SNathan Chancellor (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \ 1858156ff4a5SPeter Zijlstra $(as-instr,endbr64) 1859156ff4a5SPeter Zijlstra 1860156ff4a5SPeter Zijlstraconfig X86_KERNEL_IBT 1861156ff4a5SPeter Zijlstra prompt "Indirect Branch Tracking" 1862156ff4a5SPeter Zijlstra bool 186303f16cd0SJosh Poimboeuf depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL 1864f6a2c2b2SNathan Chancellor # https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f 1865f6a2c2b2SNathan Chancellor depends on !LD_IS_LLD || LLD_VERSION >= 140000 186603f16cd0SJosh Poimboeuf select OBJTOOL 1867156ff4a5SPeter Zijlstra help 1868156ff4a5SPeter Zijlstra Build the kernel with support for Indirect Branch Tracking, a 1869156ff4a5SPeter Zijlstra hardware support course-grain forward-edge Control Flow Integrity 1870156ff4a5SPeter Zijlstra protection. It enforces that all indirect calls must land on 1871156ff4a5SPeter Zijlstra an ENDBR instruction, as such, the compiler will instrument the 1872156ff4a5SPeter Zijlstra code with them to make this happen. 1873156ff4a5SPeter Zijlstra 1874ed53a0d9SPeter Zijlstra In addition to building the kernel with IBT, seal all functions that 18754cdfc11bSNur Hussein are not indirect call targets, avoiding them ever becoming one. 1876ed53a0d9SPeter Zijlstra 1877ed53a0d9SPeter Zijlstra This requires LTO like objtool runs and will slow down the build. It 1878ed53a0d9SPeter Zijlstra does significantly reduce the number of ENDBR instructions in the 1879ed53a0d9SPeter Zijlstra kernel image. 1880ed53a0d9SPeter Zijlstra 188135e97790SDave Hansenconfig X86_INTEL_MEMORY_PROTECTION_KEYS 188238f3e775SBabu Moger prompt "Memory Protection Keys" 188335e97790SDave Hansen def_bool y 1884284244a9SDave Hansen # Note: only available in 64-bit mode 188538f3e775SBabu Moger depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) 188652c8e601SIngo Molnar select ARCH_USES_HIGH_VMA_FLAGS 188752c8e601SIngo Molnar select ARCH_HAS_PKEYS 1888a7f7f624SMasahiro Yamada help 1889284244a9SDave Hansen Memory Protection Keys provides a mechanism for enforcing 1890284244a9SDave Hansen page-based protections, but without requiring modification of the 1891284244a9SDave Hansen page tables when an application changes protection domains. 1892284244a9SDave Hansen 18931eecbcdcSMauro Carvalho Chehab For details, see Documentation/core-api/protection-keys.rst 1894284244a9SDave Hansen 1895284244a9SDave Hansen If unsure, say y. 189635e97790SDave Hansen 1897db616173SMichal Hockochoice 1898db616173SMichal Hocko prompt "TSX enable mode" 1899db616173SMichal Hocko depends on CPU_SUP_INTEL 1900db616173SMichal Hocko default X86_INTEL_TSX_MODE_OFF 1901db616173SMichal Hocko help 1902db616173SMichal Hocko Intel's TSX (Transactional Synchronization Extensions) feature 1903db616173SMichal Hocko allows to optimize locking protocols through lock elision which 1904db616173SMichal Hocko can lead to a noticeable performance boost. 1905db616173SMichal Hocko 1906db616173SMichal Hocko On the other hand it has been shown that TSX can be exploited 1907db616173SMichal Hocko to form side channel attacks (e.g. TAA) and chances are there 1908db616173SMichal Hocko will be more of those attacks discovered in the future. 1909db616173SMichal Hocko 1910db616173SMichal Hocko Therefore TSX is not enabled by default (aka tsx=off). An admin 1911db616173SMichal Hocko might override this decision by tsx=on the command line parameter. 1912db616173SMichal Hocko Even with TSX enabled, the kernel will attempt to enable the best 1913db616173SMichal Hocko possible TAA mitigation setting depending on the microcode available 1914db616173SMichal Hocko for the particular machine. 1915db616173SMichal Hocko 1916db616173SMichal Hocko This option allows to set the default tsx mode between tsx=on, =off 1917db616173SMichal Hocko and =auto. See Documentation/admin-guide/kernel-parameters.txt for more 1918db616173SMichal Hocko details. 1919db616173SMichal Hocko 1920db616173SMichal Hocko Say off if not sure, auto if TSX is in use but it should be used on safe 1921db616173SMichal Hocko platforms or on if TSX is in use and the security aspect of tsx is not 1922db616173SMichal Hocko relevant. 1923db616173SMichal Hocko 1924db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_OFF 1925db616173SMichal Hocko bool "off" 1926db616173SMichal Hocko help 1927db616173SMichal Hocko TSX is disabled if possible - equals to tsx=off command line parameter. 1928db616173SMichal Hocko 1929db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_ON 1930db616173SMichal Hocko bool "on" 1931db616173SMichal Hocko help 1932db616173SMichal Hocko TSX is always enabled on TSX capable HW - equals the tsx=on command 1933db616173SMichal Hocko line parameter. 1934db616173SMichal Hocko 1935db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_AUTO 1936db616173SMichal Hocko bool "auto" 1937db616173SMichal Hocko help 1938db616173SMichal Hocko TSX is enabled on TSX capable HW that is believed to be safe against 1939db616173SMichal Hocko side channel attacks- equals the tsx=auto command line parameter. 1940db616173SMichal Hockoendchoice 1941db616173SMichal Hocko 1942e7e05452SSean Christophersonconfig X86_SGX 1943e7e05452SSean Christopherson bool "Software Guard eXtensions (SGX)" 1944e7e05452SSean Christopherson depends on X86_64 && CPU_SUP_INTEL 1945e7e05452SSean Christopherson depends on CRYPTO=y 1946e7e05452SSean Christopherson depends on CRYPTO_SHA256=y 1947e7e05452SSean Christopherson select SRCU 1948e7e05452SSean Christopherson select MMU_NOTIFIER 1949901ddbb9SJarkko Sakkinen select NUMA_KEEP_MEMINFO if NUMA 195040e0e784STony Luck select XARRAY_MULTI 1951e7e05452SSean Christopherson help 1952e7e05452SSean Christopherson Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions 1953e7e05452SSean Christopherson that can be used by applications to set aside private regions of code 1954e7e05452SSean Christopherson and data, referred to as enclaves. An enclave's private memory can 1955e7e05452SSean Christopherson only be accessed by code running within the enclave. Accesses from 1956e7e05452SSean Christopherson outside the enclave, including other enclaves, are disallowed by 1957e7e05452SSean Christopherson hardware. 1958e7e05452SSean Christopherson 1959e7e05452SSean Christopherson If unsure, say N. 1960e7e05452SSean Christopherson 1961506f1d07SSam Ravnborgconfig EFI 19629ba16087SJan Beulich bool "EFI runtime service support" 19635b83683fSHuang, Ying depends on ACPI 1964f6ce5002SSergey Vlasov select UCS2_STRING 1965022ee6c5SArd Biesheuvel select EFI_RUNTIME_WRAPPERS 19661ff2fc02STom Lendacky select ARCH_USE_MEMREMAP_PROT 1967a7f7f624SMasahiro Yamada help 19688b2cb7a8SHuang, Ying This enables the kernel to use EFI runtime services that are 1969506f1d07SSam Ravnborg available (such as the EFI variable services). 1970506f1d07SSam Ravnborg 19718b2cb7a8SHuang, Ying This option is only useful on systems that have EFI firmware. 19728b2cb7a8SHuang, Ying In addition, you should use the latest ELILO loader available 19738b2cb7a8SHuang, Ying at <http://elilo.sourceforge.net> in order to take advantage 19748b2cb7a8SHuang, Ying of EFI runtime services. However, even with this option, the 19758b2cb7a8SHuang, Ying resultant kernel should continue to boot on existing non-EFI 19768b2cb7a8SHuang, Ying platforms. 1977506f1d07SSam Ravnborg 1978291f3632SMatt Flemingconfig EFI_STUB 1979291f3632SMatt Fleming bool "EFI stub support" 1980c6dbd3e5SPeter Zijlstra depends on EFI 19818f24f8c2SArd Biesheuvel depends on $(cc-option,-mabi=ms) || X86_32 19827b2a583aSMatt Fleming select RELOCATABLE 1983a7f7f624SMasahiro Yamada help 1984291f3632SMatt Fleming This kernel feature allows a bzImage to be loaded directly 1985291f3632SMatt Fleming by EFI firmware without the use of a bootloader. 1986291f3632SMatt Fleming 19874f4cfa6cSMauro Carvalho Chehab See Documentation/admin-guide/efi-stub.rst for more information. 19880c759662SMatt Fleming 19897d453eeeSMatt Flemingconfig EFI_MIXED 19907d453eeeSMatt Fleming bool "EFI mixed-mode support" 19917d453eeeSMatt Fleming depends on EFI_STUB && X86_64 1992a7f7f624SMasahiro Yamada help 19937d453eeeSMatt Fleming Enabling this feature allows a 64-bit kernel to be booted 19947d453eeeSMatt Fleming on a 32-bit firmware, provided that your CPU supports 64-bit 19957d453eeeSMatt Fleming mode. 19967d453eeeSMatt Fleming 19977d453eeeSMatt Fleming Note that it is not possible to boot a mixed-mode enabled 19987d453eeeSMatt Fleming kernel via the EFI boot stub - a bootloader that supports 19997d453eeeSMatt Fleming the EFI handover protocol must be used. 20007d453eeeSMatt Fleming 20017d453eeeSMatt Fleming If unsure, say N. 20027d453eeeSMatt Fleming 20038636a1f9SMasahiro Yamadasource "kernel/Kconfig.hz" 2004506f1d07SSam Ravnborg 2005506f1d07SSam Ravnborgconfig KEXEC 2006506f1d07SSam Ravnborg bool "kexec system call" 20072965faa5SDave Young select KEXEC_CORE 2008a7f7f624SMasahiro Yamada help 2009506f1d07SSam Ravnborg kexec is a system call that implements the ability to shutdown your 2010506f1d07SSam Ravnborg current kernel, and to start another kernel. It is like a reboot 2011506f1d07SSam Ravnborg but it is independent of the system firmware. And like a reboot 2012506f1d07SSam Ravnborg you can start any kernel with it, not just Linux. 2013506f1d07SSam Ravnborg 2014506f1d07SSam Ravnborg The name comes from the similarity to the exec system call. 2015506f1d07SSam Ravnborg 2016506f1d07SSam Ravnborg It is an ongoing process to be certain the hardware in a machine 2017506f1d07SSam Ravnborg is properly shutdown, so do not be surprised if this code does not 2018bf220695SGeert Uytterhoeven initially work for you. As of this writing the exact hardware 2019bf220695SGeert Uytterhoeven interface is strongly in flux, so no good recommendation can be 2020bf220695SGeert Uytterhoeven made. 2021506f1d07SSam Ravnborg 202274ca317cSVivek Goyalconfig KEXEC_FILE 202374ca317cSVivek Goyal bool "kexec file based system call" 20242965faa5SDave Young select KEXEC_CORE 202574ca317cSVivek Goyal select BUILD_BIN2C 202674ca317cSVivek Goyal depends on X86_64 202774ca317cSVivek Goyal depends on CRYPTO=y 202874ca317cSVivek Goyal depends on CRYPTO_SHA256=y 2029a7f7f624SMasahiro Yamada help 203074ca317cSVivek Goyal This is new version of kexec system call. This system call is 203174ca317cSVivek Goyal file based and takes file descriptors as system call argument 203274ca317cSVivek Goyal for kernel and initramfs as opposed to list of segments as 203374ca317cSVivek Goyal accepted by previous system call. 203474ca317cSVivek Goyal 2035b799a09fSAKASHI Takahiroconfig ARCH_HAS_KEXEC_PURGATORY 2036b799a09fSAKASHI Takahiro def_bool KEXEC_FILE 2037b799a09fSAKASHI Takahiro 203899d5cadfSJiri Bohacconfig KEXEC_SIG 20398e7d8381SVivek Goyal bool "Verify kernel signature during kexec_file_load() syscall" 204074ca317cSVivek Goyal depends on KEXEC_FILE 2041a7f7f624SMasahiro Yamada help 204299d5cadfSJiri Bohac 204399d5cadfSJiri Bohac This option makes the kexec_file_load() syscall check for a valid 204499d5cadfSJiri Bohac signature of the kernel image. The image can still be loaded without 204599d5cadfSJiri Bohac a valid signature unless you also enable KEXEC_SIG_FORCE, though if 204699d5cadfSJiri Bohac there's a signature that we can check, then it must be valid. 204799d5cadfSJiri Bohac 204899d5cadfSJiri Bohac In addition to this option, you need to enable signature 204999d5cadfSJiri Bohac verification for the corresponding kernel image type being 205099d5cadfSJiri Bohac loaded in order for this to work. 205199d5cadfSJiri Bohac 205299d5cadfSJiri Bohacconfig KEXEC_SIG_FORCE 205399d5cadfSJiri Bohac bool "Require a valid signature in kexec_file_load() syscall" 205499d5cadfSJiri Bohac depends on KEXEC_SIG 2055a7f7f624SMasahiro Yamada help 20568e7d8381SVivek Goyal This option makes kernel signature verification mandatory for 2057d8eb8940SBorislav Petkov the kexec_file_load() syscall. 20588e7d8381SVivek Goyal 20598e7d8381SVivek Goyalconfig KEXEC_BZIMAGE_VERIFY_SIG 20608e7d8381SVivek Goyal bool "Enable bzImage signature verification support" 206199d5cadfSJiri Bohac depends on KEXEC_SIG 20628e7d8381SVivek Goyal depends on SIGNED_PE_FILE_VERIFICATION 20638e7d8381SVivek Goyal select SYSTEM_TRUSTED_KEYRING 2064a7f7f624SMasahiro Yamada help 20658e7d8381SVivek Goyal Enable bzImage signature verification support. 20668e7d8381SVivek Goyal 2067506f1d07SSam Ravnborgconfig CRASH_DUMP 206804b69447SPavel Machek bool "kernel crash dumps" 2069506f1d07SSam Ravnborg depends on X86_64 || (X86_32 && HIGHMEM) 2070a7f7f624SMasahiro Yamada help 2071506f1d07SSam Ravnborg Generate crash dump after being started by kexec. 2072506f1d07SSam Ravnborg This should be normally only set in special crash dump kernels 2073506f1d07SSam Ravnborg which are loaded in the main kernel with kexec-tools into 2074506f1d07SSam Ravnborg a specially reserved region and then later executed after 2075506f1d07SSam Ravnborg a crash by kdump/kexec. The crash dump kernel must be compiled 2076506f1d07SSam Ravnborg to a memory address not used by the main kernel or BIOS using 2077506f1d07SSam Ravnborg PHYSICAL_START, or it must be built as a relocatable image 2078506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y). 2079330d4810SMauro Carvalho Chehab For more details see Documentation/admin-guide/kdump/kdump.rst 2080506f1d07SSam Ravnborg 20813ab83521SHuang Yingconfig KEXEC_JUMP 20826ea30386SKees Cook bool "kexec jump" 2083fee7b0d8SHuang Ying depends on KEXEC && HIBERNATION 2084a7f7f624SMasahiro Yamada help 208589081d17SHuang Ying Jump between original kernel and kexeced kernel and invoke 208689081d17SHuang Ying code in physical address mode via KEXEC 20873ab83521SHuang Ying 2088506f1d07SSam Ravnborgconfig PHYSICAL_START 20896a108a14SDavid Rientjes hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP) 2090ceefccc9SH. Peter Anvin default "0x1000000" 2091a7f7f624SMasahiro Yamada help 2092506f1d07SSam Ravnborg This gives the physical address where the kernel is loaded. 2093506f1d07SSam Ravnborg 2094506f1d07SSam Ravnborg If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then 2095506f1d07SSam Ravnborg bzImage will decompress itself to above physical address and 2096506f1d07SSam Ravnborg run from there. Otherwise, bzImage will run from the address where 2097506f1d07SSam Ravnborg it has been loaded by the boot loader and will ignore above physical 2098506f1d07SSam Ravnborg address. 2099506f1d07SSam Ravnborg 2100506f1d07SSam Ravnborg In normal kdump cases one does not have to set/change this option 2101506f1d07SSam Ravnborg as now bzImage can be compiled as a completely relocatable image 2102506f1d07SSam Ravnborg (CONFIG_RELOCATABLE=y) and be used to load and run from a different 2103506f1d07SSam Ravnborg address. This option is mainly useful for the folks who don't want 2104506f1d07SSam Ravnborg to use a bzImage for capturing the crash dump and want to use a 2105506f1d07SSam Ravnborg vmlinux instead. vmlinux is not relocatable hence a kernel needs 2106506f1d07SSam Ravnborg to be specifically compiled to run from a specific memory area 2107506f1d07SSam Ravnborg (normally a reserved region) and this option comes handy. 2108506f1d07SSam Ravnborg 2109ceefccc9SH. Peter Anvin So if you are using bzImage for capturing the crash dump, 2110ceefccc9SH. Peter Anvin leave the value here unchanged to 0x1000000 and set 2111ceefccc9SH. Peter Anvin CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux 2112ceefccc9SH. Peter Anvin for capturing the crash dump change this value to start of 2113ceefccc9SH. Peter Anvin the reserved region. In other words, it can be set based on 2114ceefccc9SH. Peter Anvin the "X" value as specified in the "crashkernel=YM@XM" 2115ceefccc9SH. Peter Anvin command line boot parameter passed to the panic-ed 2116330d4810SMauro Carvalho Chehab kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst 2117ceefccc9SH. Peter Anvin for more details about crash dumps. 2118506f1d07SSam Ravnborg 2119506f1d07SSam Ravnborg Usage of bzImage for capturing the crash dump is recommended as 2120506f1d07SSam Ravnborg one does not have to build two kernels. Same kernel can be used 2121506f1d07SSam Ravnborg as production kernel and capture kernel. Above option should have 2122506f1d07SSam Ravnborg gone away after relocatable bzImage support is introduced. But it 2123506f1d07SSam Ravnborg is present because there are users out there who continue to use 2124506f1d07SSam Ravnborg vmlinux for dump capture. This option should go away down the 2125506f1d07SSam Ravnborg line. 2126506f1d07SSam Ravnborg 2127506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2128506f1d07SSam Ravnborg 2129506f1d07SSam Ravnborgconfig RELOCATABLE 213026717808SH. Peter Anvin bool "Build a relocatable kernel" 213126717808SH. Peter Anvin default y 2132a7f7f624SMasahiro Yamada help 2133506f1d07SSam Ravnborg This builds a kernel image that retains relocation information 2134506f1d07SSam Ravnborg so it can be loaded someplace besides the default 1MB. 2135506f1d07SSam Ravnborg The relocations tend to make the kernel binary about 10% larger, 2136506f1d07SSam Ravnborg but are discarded at runtime. 2137506f1d07SSam Ravnborg 2138506f1d07SSam Ravnborg One use is for the kexec on panic case where the recovery kernel 2139506f1d07SSam Ravnborg must live at a different physical address than the primary 2140506f1d07SSam Ravnborg kernel. 2141506f1d07SSam Ravnborg 2142506f1d07SSam Ravnborg Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address 2143506f1d07SSam Ravnborg it has been loaded at and the compile time physical address 21448ab3820fSKees Cook (CONFIG_PHYSICAL_START) is used as the minimum location. 2145506f1d07SSam Ravnborg 21468ab3820fSKees Cookconfig RANDOMIZE_BASE 2147e8581e3dSBaoquan He bool "Randomize the address of the kernel image (KASLR)" 21488ab3820fSKees Cook depends on RELOCATABLE 21496807c846SIngo Molnar default y 2150a7f7f624SMasahiro Yamada help 2151e8581e3dSBaoquan He In support of Kernel Address Space Layout Randomization (KASLR), 2152e8581e3dSBaoquan He this randomizes the physical address at which the kernel image 2153e8581e3dSBaoquan He is decompressed and the virtual address where the kernel 2154e8581e3dSBaoquan He image is mapped, as a security feature that deters exploit 2155e8581e3dSBaoquan He attempts relying on knowledge of the location of kernel 2156e8581e3dSBaoquan He code internals. 2157e8581e3dSBaoquan He 2158ed9f007eSKees Cook On 64-bit, the kernel physical and virtual addresses are 2159ed9f007eSKees Cook randomized separately. The physical address will be anywhere 2160ed9f007eSKees Cook between 16MB and the top of physical memory (up to 64TB). The 2161ed9f007eSKees Cook virtual address will be randomized from 16MB up to 1GB (9 bits 2162ed9f007eSKees Cook of entropy). Note that this also reduces the memory space 2163ed9f007eSKees Cook available to kernel modules from 1.5GB to 1GB. 2164ed9f007eSKees Cook 2165ed9f007eSKees Cook On 32-bit, the kernel physical and virtual addresses are 2166ed9f007eSKees Cook randomized together. They will be randomized from 16MB up to 2167ed9f007eSKees Cook 512MB (8 bits of entropy). 21688ab3820fSKees Cook 2169a653f356SKees Cook Entropy is generated using the RDRAND instruction if it is 2170e8581e3dSBaoquan He supported. If RDTSC is supported, its value is mixed into 2171e8581e3dSBaoquan He the entropy pool as well. If neither RDRAND nor RDTSC are 2172ed9f007eSKees Cook supported, then entropy is read from the i8254 timer. The 2173ed9f007eSKees Cook usable entropy is limited by the kernel being built using 2174ed9f007eSKees Cook 2GB addressing, and that PHYSICAL_ALIGN must be at a 2175ed9f007eSKees Cook minimum of 2MB. As a result, only 10 bits of entropy are 2176ed9f007eSKees Cook theoretically possible, but the implementations are further 2177ed9f007eSKees Cook limited due to memory layouts. 2178e8581e3dSBaoquan He 21796807c846SIngo Molnar If unsure, say Y. 2180da2b6fb9SKees Cook 21818ab3820fSKees Cook# Relocation on x86 needs some additional build support 2182845adf72SH. Peter Anvinconfig X86_NEED_RELOCS 2183845adf72SH. Peter Anvin def_bool y 21848ab3820fSKees Cook depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) 2185845adf72SH. Peter Anvin 2186506f1d07SSam Ravnborgconfig PHYSICAL_ALIGN 2187a0215061SKees Cook hex "Alignment value to which kernel should be aligned" 21888ab3820fSKees Cook default "0x200000" 2189a0215061SKees Cook range 0x2000 0x1000000 if X86_32 2190a0215061SKees Cook range 0x200000 0x1000000 if X86_64 2191a7f7f624SMasahiro Yamada help 2192506f1d07SSam Ravnborg This value puts the alignment restrictions on physical address 2193506f1d07SSam Ravnborg where kernel is loaded and run from. Kernel is compiled for an 2194506f1d07SSam Ravnborg address which meets above alignment restriction. 2195506f1d07SSam Ravnborg 2196506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2197506f1d07SSam Ravnborg CONFIG_RELOCATABLE is set, kernel will move itself to nearest 2198506f1d07SSam Ravnborg address aligned to above value and run from there. 2199506f1d07SSam Ravnborg 2200506f1d07SSam Ravnborg If bootloader loads the kernel at a non-aligned address and 2201506f1d07SSam Ravnborg CONFIG_RELOCATABLE is not set, kernel will ignore the run time 2202506f1d07SSam Ravnborg load address and decompress itself to the address it has been 2203506f1d07SSam Ravnborg compiled for and run from there. The address for which kernel is 2204506f1d07SSam Ravnborg compiled already meets above alignment restrictions. Hence the 2205506f1d07SSam Ravnborg end result is that kernel runs from a physical address meeting 2206506f1d07SSam Ravnborg above alignment restrictions. 2207506f1d07SSam Ravnborg 2208a0215061SKees Cook On 32-bit this value must be a multiple of 0x2000. On 64-bit 2209a0215061SKees Cook this value must be a multiple of 0x200000. 2210a0215061SKees Cook 2211506f1d07SSam Ravnborg Don't change this unless you know what you are doing. 2212506f1d07SSam Ravnborg 2213eedb92abSKirill A. Shutemovconfig DYNAMIC_MEMORY_LAYOUT 2214eedb92abSKirill A. Shutemov bool 2215a7f7f624SMasahiro Yamada help 2216eedb92abSKirill A. Shutemov This option makes base addresses of vmalloc and vmemmap as well as 2217eedb92abSKirill A. Shutemov __PAGE_OFFSET movable during boot. 2218eedb92abSKirill A. Shutemov 22190483e1faSThomas Garnierconfig RANDOMIZE_MEMORY 22200483e1faSThomas Garnier bool "Randomize the kernel memory sections" 22210483e1faSThomas Garnier depends on X86_64 22220483e1faSThomas Garnier depends on RANDOMIZE_BASE 2223eedb92abSKirill A. Shutemov select DYNAMIC_MEMORY_LAYOUT 22240483e1faSThomas Garnier default RANDOMIZE_BASE 2225a7f7f624SMasahiro Yamada help 22260483e1faSThomas Garnier Randomizes the base virtual address of kernel memory sections 22270483e1faSThomas Garnier (physical memory mapping, vmalloc & vmemmap). This security feature 22280483e1faSThomas Garnier makes exploits relying on predictable memory locations less reliable. 22290483e1faSThomas Garnier 22300483e1faSThomas Garnier The order of allocations remains unchanged. Entropy is generated in 22310483e1faSThomas Garnier the same way as RANDOMIZE_BASE. Current implementation in the optimal 22320483e1faSThomas Garnier configuration have in average 30,000 different possible virtual 22330483e1faSThomas Garnier addresses for each memory section. 22340483e1faSThomas Garnier 22356807c846SIngo Molnar If unsure, say Y. 22360483e1faSThomas Garnier 223790397a41SThomas Garnierconfig RANDOMIZE_MEMORY_PHYSICAL_PADDING 223890397a41SThomas Garnier hex "Physical memory mapping padding" if EXPERT 223990397a41SThomas Garnier depends on RANDOMIZE_MEMORY 224090397a41SThomas Garnier default "0xa" if MEMORY_HOTPLUG 224190397a41SThomas Garnier default "0x0" 224290397a41SThomas Garnier range 0x1 0x40 if MEMORY_HOTPLUG 224390397a41SThomas Garnier range 0x0 0x40 2244a7f7f624SMasahiro Yamada help 224590397a41SThomas Garnier Define the padding in terabytes added to the existing physical 224690397a41SThomas Garnier memory size during kernel memory randomization. It is useful 224790397a41SThomas Garnier for memory hotplug support but reduces the entropy available for 224890397a41SThomas Garnier address randomization. 224990397a41SThomas Garnier 225090397a41SThomas Garnier If unsure, leave at the default value. 225190397a41SThomas Garnier 2252506f1d07SSam Ravnborgconfig HOTPLUG_CPU 2253bebd024eSThomas Gleixner def_bool y 225440b31360SStephen Rothwell depends on SMP 2255506f1d07SSam Ravnborg 225680aa1dffSFenghua Yuconfig BOOTPARAM_HOTPLUG_CPU0 225780aa1dffSFenghua Yu bool "Set default setting of cpu0_hotpluggable" 22582c922cd0SKees Cook depends on HOTPLUG_CPU 2259a7f7f624SMasahiro Yamada help 226080aa1dffSFenghua Yu Set whether default state of cpu0_hotpluggable is on or off. 226180aa1dffSFenghua Yu 226280aa1dffSFenghua Yu Say Y here to enable CPU0 hotplug by default. If this switch 226380aa1dffSFenghua Yu is turned on, there is no need to give cpu0_hotplug kernel 226480aa1dffSFenghua Yu parameter and the CPU0 hotplug feature is enabled by default. 226580aa1dffSFenghua Yu 226680aa1dffSFenghua Yu Please note: there are two known CPU0 dependencies if you want 226780aa1dffSFenghua Yu to enable the CPU0 hotplug feature either by this switch or by 226880aa1dffSFenghua Yu cpu0_hotplug kernel parameter. 226980aa1dffSFenghua Yu 227080aa1dffSFenghua Yu First, resume from hibernate or suspend always starts from CPU0. 227180aa1dffSFenghua Yu So hibernate and suspend are prevented if CPU0 is offline. 227280aa1dffSFenghua Yu 227380aa1dffSFenghua Yu Second dependency is PIC interrupts always go to CPU0. CPU0 can not 227480aa1dffSFenghua Yu offline if any interrupt can not migrate out of CPU0. There may 227580aa1dffSFenghua Yu be other CPU0 dependencies. 227680aa1dffSFenghua Yu 227780aa1dffSFenghua Yu Please make sure the dependencies are under your control before 227880aa1dffSFenghua Yu you enable this feature. 227980aa1dffSFenghua Yu 228080aa1dffSFenghua Yu Say N if you don't want to enable CPU0 hotplug feature by default. 228180aa1dffSFenghua Yu You still can enable the CPU0 hotplug feature at boot by kernel 228280aa1dffSFenghua Yu parameter cpu0_hotplug. 228380aa1dffSFenghua Yu 2284a71c8bc5SFenghua Yuconfig DEBUG_HOTPLUG_CPU0 2285a71c8bc5SFenghua Yu def_bool n 2286a71c8bc5SFenghua Yu prompt "Debug CPU0 hotplug" 22872c922cd0SKees Cook depends on HOTPLUG_CPU 2288a7f7f624SMasahiro Yamada help 2289a71c8bc5SFenghua Yu Enabling this option offlines CPU0 (if CPU0 can be offlined) as 2290a71c8bc5SFenghua Yu soon as possible and boots up userspace with CPU0 offlined. User 2291a71c8bc5SFenghua Yu can online CPU0 back after boot time. 2292a71c8bc5SFenghua Yu 2293a71c8bc5SFenghua Yu To debug CPU0 hotplug, you need to enable CPU0 offline/online 2294a71c8bc5SFenghua Yu feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during 2295a71c8bc5SFenghua Yu compilation or giving cpu0_hotplug kernel parameter at boot. 2296a71c8bc5SFenghua Yu 2297a71c8bc5SFenghua Yu If unsure, say N. 2298a71c8bc5SFenghua Yu 2299506f1d07SSam Ravnborgconfig COMPAT_VDSO 2300b0b49f26SAndy Lutomirski def_bool n 2301b0b49f26SAndy Lutomirski prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)" 2302953fee1dSIngo Molnar depends on COMPAT_32 2303a7f7f624SMasahiro Yamada help 2304b0b49f26SAndy Lutomirski Certain buggy versions of glibc will crash if they are 2305b0b49f26SAndy Lutomirski presented with a 32-bit vDSO that is not mapped at the address 2306b0b49f26SAndy Lutomirski indicated in its segment table. 2307e84446deSRandy Dunlap 2308b0b49f26SAndy Lutomirski The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a 2309b0b49f26SAndy Lutomirski and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and 2310b0b49f26SAndy Lutomirski 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is 2311b0b49f26SAndy Lutomirski the only released version with the bug, but OpenSUSE 9 2312b0b49f26SAndy Lutomirski contains a buggy "glibc 2.3.2". 2313506f1d07SSam Ravnborg 2314b0b49f26SAndy Lutomirski The symptom of the bug is that everything crashes on startup, saying: 2315b0b49f26SAndy Lutomirski dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed! 2316b0b49f26SAndy Lutomirski 2317b0b49f26SAndy Lutomirski Saying Y here changes the default value of the vdso32 boot 2318b0b49f26SAndy Lutomirski option from 1 to 0, which turns off the 32-bit vDSO entirely. 2319b0b49f26SAndy Lutomirski This works around the glibc bug but hurts performance. 2320b0b49f26SAndy Lutomirski 2321b0b49f26SAndy Lutomirski If unsure, say N: if you are compiling your own kernel, you 2322b0b49f26SAndy Lutomirski are unlikely to be using a buggy version of glibc. 2323506f1d07SSam Ravnborg 23243dc33bd3SKees Cookchoice 23253dc33bd3SKees Cook prompt "vsyscall table for legacy applications" 23263dc33bd3SKees Cook depends on X86_64 2327625b7b7fSAndy Lutomirski default LEGACY_VSYSCALL_XONLY 23283dc33bd3SKees Cook help 23293dc33bd3SKees Cook Legacy user code that does not know how to find the vDSO expects 23303dc33bd3SKees Cook to be able to issue three syscalls by calling fixed addresses in 23313dc33bd3SKees Cook kernel space. Since this location is not randomized with ASLR, 23323dc33bd3SKees Cook it can be used to assist security vulnerability exploitation. 23333dc33bd3SKees Cook 23343dc33bd3SKees Cook This setting can be changed at boot time via the kernel command 2335bd49e16eSAndy Lutomirski line parameter vsyscall=[emulate|xonly|none]. 23363dc33bd3SKees Cook 23373dc33bd3SKees Cook On a system with recent enough glibc (2.14 or newer) and no 23383dc33bd3SKees Cook static binaries, you can say None without a performance penalty 23393dc33bd3SKees Cook to improve security. 23403dc33bd3SKees Cook 2341bd49e16eSAndy Lutomirski If unsure, select "Emulate execution only". 23423dc33bd3SKees Cook 23433dc33bd3SKees Cook config LEGACY_VSYSCALL_EMULATE 2344bd49e16eSAndy Lutomirski bool "Full emulation" 23453dc33bd3SKees Cook help 2346bd49e16eSAndy Lutomirski The kernel traps and emulates calls into the fixed vsyscall 2347bd49e16eSAndy Lutomirski address mapping. This makes the mapping non-executable, but 2348bd49e16eSAndy Lutomirski it still contains readable known contents, which could be 2349bd49e16eSAndy Lutomirski used in certain rare security vulnerability exploits. This 2350bd49e16eSAndy Lutomirski configuration is recommended when using legacy userspace 2351bd49e16eSAndy Lutomirski that still uses vsyscalls along with legacy binary 2352bd49e16eSAndy Lutomirski instrumentation tools that require code to be readable. 2353bd49e16eSAndy Lutomirski 2354bd49e16eSAndy Lutomirski An example of this type of legacy userspace is running 2355bd49e16eSAndy Lutomirski Pin on an old binary that still uses vsyscalls. 2356bd49e16eSAndy Lutomirski 2357bd49e16eSAndy Lutomirski config LEGACY_VSYSCALL_XONLY 2358bd49e16eSAndy Lutomirski bool "Emulate execution only" 2359bd49e16eSAndy Lutomirski help 2360bd49e16eSAndy Lutomirski The kernel traps and emulates calls into the fixed vsyscall 2361bd49e16eSAndy Lutomirski address mapping and does not allow reads. This 2362bd49e16eSAndy Lutomirski configuration is recommended when userspace might use the 2363bd49e16eSAndy Lutomirski legacy vsyscall area but support for legacy binary 2364bd49e16eSAndy Lutomirski instrumentation of legacy code is not needed. It mitigates 2365bd49e16eSAndy Lutomirski certain uses of the vsyscall area as an ASLR-bypassing 2366bd49e16eSAndy Lutomirski buffer. 23673dc33bd3SKees Cook 23683dc33bd3SKees Cook config LEGACY_VSYSCALL_NONE 23693dc33bd3SKees Cook bool "None" 23703dc33bd3SKees Cook help 23713dc33bd3SKees Cook There will be no vsyscall mapping at all. This will 23723dc33bd3SKees Cook eliminate any risk of ASLR bypass due to the vsyscall 23733dc33bd3SKees Cook fixed address mapping. Attempts to use the vsyscalls 23743dc33bd3SKees Cook will be reported to dmesg, so that either old or 23753dc33bd3SKees Cook malicious userspace programs can be identified. 23763dc33bd3SKees Cook 23773dc33bd3SKees Cookendchoice 23783dc33bd3SKees Cook 2379516cbf37STim Birdconfig CMDLINE_BOOL 2380516cbf37STim Bird bool "Built-in kernel command line" 2381a7f7f624SMasahiro Yamada help 2382516cbf37STim Bird Allow for specifying boot arguments to the kernel at 2383516cbf37STim Bird build time. On some systems (e.g. embedded ones), it is 2384516cbf37STim Bird necessary or convenient to provide some or all of the 2385516cbf37STim Bird kernel boot arguments with the kernel itself (that is, 2386516cbf37STim Bird to not rely on the boot loader to provide them.) 2387516cbf37STim Bird 2388516cbf37STim Bird To compile command line arguments into the kernel, 2389516cbf37STim Bird set this option to 'Y', then fill in the 239069711ca1SSébastien Hinderer boot arguments in CONFIG_CMDLINE. 2391516cbf37STim Bird 2392516cbf37STim Bird Systems with fully functional boot loaders (i.e. non-embedded) 2393516cbf37STim Bird should leave this option set to 'N'. 2394516cbf37STim Bird 2395516cbf37STim Birdconfig CMDLINE 2396516cbf37STim Bird string "Built-in kernel command string" 2397516cbf37STim Bird depends on CMDLINE_BOOL 2398516cbf37STim Bird default "" 2399a7f7f624SMasahiro Yamada help 2400516cbf37STim Bird Enter arguments here that should be compiled into the kernel 2401516cbf37STim Bird image and used at boot time. If the boot loader provides a 2402516cbf37STim Bird command line at boot time, it is appended to this string to 2403516cbf37STim Bird form the full kernel command line, when the system boots. 2404516cbf37STim Bird 2405516cbf37STim Bird However, you can use the CONFIG_CMDLINE_OVERRIDE option to 2406516cbf37STim Bird change this behavior. 2407516cbf37STim Bird 2408516cbf37STim Bird In most cases, the command line (whether built-in or provided 2409516cbf37STim Bird by the boot loader) should specify the device for the root 2410516cbf37STim Bird file system. 2411516cbf37STim Bird 2412516cbf37STim Birdconfig CMDLINE_OVERRIDE 2413516cbf37STim Bird bool "Built-in command line overrides boot loader arguments" 2414645e6466SAnders Roxell depends on CMDLINE_BOOL && CMDLINE != "" 2415a7f7f624SMasahiro Yamada help 2416516cbf37STim Bird Set this option to 'Y' to have the kernel ignore the boot loader 2417516cbf37STim Bird command line, and use ONLY the built-in command line. 2418516cbf37STim Bird 2419516cbf37STim Bird This is used to work around broken boot loaders. This should 2420516cbf37STim Bird be set to 'N' under normal conditions. 2421516cbf37STim Bird 2422a5b9e5a2SAndy Lutomirskiconfig MODIFY_LDT_SYSCALL 2423a5b9e5a2SAndy Lutomirski bool "Enable the LDT (local descriptor table)" if EXPERT 2424a5b9e5a2SAndy Lutomirski default y 2425a7f7f624SMasahiro Yamada help 2426a5b9e5a2SAndy Lutomirski Linux can allow user programs to install a per-process x86 2427a5b9e5a2SAndy Lutomirski Local Descriptor Table (LDT) using the modify_ldt(2) system 2428a5b9e5a2SAndy Lutomirski call. This is required to run 16-bit or segmented code such as 2429a5b9e5a2SAndy Lutomirski DOSEMU or some Wine programs. It is also used by some very old 2430a5b9e5a2SAndy Lutomirski threading libraries. 2431a5b9e5a2SAndy Lutomirski 2432a5b9e5a2SAndy Lutomirski Enabling this feature adds a small amount of overhead to 2433a5b9e5a2SAndy Lutomirski context switches and increases the low-level kernel attack 2434a5b9e5a2SAndy Lutomirski surface. Disabling it removes the modify_ldt(2) system call. 2435a5b9e5a2SAndy Lutomirski 2436a5b9e5a2SAndy Lutomirski Saying 'N' here may make sense for embedded or server kernels. 2437a5b9e5a2SAndy Lutomirski 24383aac3ebeSThomas Gleixnerconfig STRICT_SIGALTSTACK_SIZE 24393aac3ebeSThomas Gleixner bool "Enforce strict size checking for sigaltstack" 24403aac3ebeSThomas Gleixner depends on DYNAMIC_SIGFRAME 24413aac3ebeSThomas Gleixner help 24423aac3ebeSThomas Gleixner For historical reasons MINSIGSTKSZ is a constant which became 24433aac3ebeSThomas Gleixner already too small with AVX512 support. Add a mechanism to 24443aac3ebeSThomas Gleixner enforce strict checking of the sigaltstack size against the 24453aac3ebeSThomas Gleixner real size of the FPU frame. This option enables the check 24463aac3ebeSThomas Gleixner by default. It can also be controlled via the kernel command 24473aac3ebeSThomas Gleixner line option 'strict_sas_size' independent of this config 24483aac3ebeSThomas Gleixner switch. Enabling it might break existing applications which 24493aac3ebeSThomas Gleixner allocate a too small sigaltstack but 'work' because they 24503aac3ebeSThomas Gleixner never get a signal delivered. 24513aac3ebeSThomas Gleixner 24523aac3ebeSThomas Gleixner Say 'N' unless you want to really enforce this check. 24533aac3ebeSThomas Gleixner 2454b700e7f0SSeth Jenningssource "kernel/livepatch/Kconfig" 2455b700e7f0SSeth Jennings 2456506f1d07SSam Ravnborgendmenu 2457506f1d07SSam Ravnborg 24583072e413SMichal Hockoconfig ARCH_HAS_ADD_PAGES 24593072e413SMichal Hocko def_bool y 24605c11f00bSDavid Hildenbrand depends on ARCH_ENABLE_MEMORY_HOTPLUG 24613072e413SMichal Hocko 2462f91ef222SOscar Salvadorconfig ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 2463f91ef222SOscar Salvador def_bool y 2464f91ef222SOscar Salvador 2465da85f865SBjorn Helgaasmenu "Power management and ACPI options" 2466e279b6c1SSam Ravnborg 2467e279b6c1SSam Ravnborgconfig ARCH_HIBERNATION_HEADER 24683c2362e6SHarvey Harrison def_bool y 246944556530SZhimin Gu depends on HIBERNATION 2470e279b6c1SSam Ravnborg 2471e279b6c1SSam Ravnborgsource "kernel/power/Kconfig" 2472e279b6c1SSam Ravnborg 2473e279b6c1SSam Ravnborgsource "drivers/acpi/Kconfig" 2474e279b6c1SSam Ravnborg 2475a6b68076SAndi Kleenconfig X86_APM_BOOT 24766fc108a0SJan Beulich def_bool y 2477282e5aabSPaul Bolle depends on APM 2478a6b68076SAndi Kleen 2479e279b6c1SSam Ravnborgmenuconfig APM 2480e279b6c1SSam Ravnborg tristate "APM (Advanced Power Management) BIOS support" 2481efefa6f6SIngo Molnar depends on X86_32 && PM_SLEEP 2482a7f7f624SMasahiro Yamada help 2483e279b6c1SSam Ravnborg APM is a BIOS specification for saving power using several different 2484e279b6c1SSam Ravnborg techniques. This is mostly useful for battery powered laptops with 2485e279b6c1SSam Ravnborg APM compliant BIOSes. If you say Y here, the system time will be 2486e279b6c1SSam Ravnborg reset after a RESUME operation, the /proc/apm device will provide 2487e279b6c1SSam Ravnborg battery status information, and user-space programs will receive 2488e279b6c1SSam Ravnborg notification of APM "events" (e.g. battery status change). 2489e279b6c1SSam Ravnborg 2490e279b6c1SSam Ravnborg If you select "Y" here, you can disable actual use of the APM 2491e279b6c1SSam Ravnborg BIOS by passing the "apm=off" option to the kernel at boot time. 2492e279b6c1SSam Ravnborg 2493e279b6c1SSam Ravnborg Note that the APM support is almost completely disabled for 2494e279b6c1SSam Ravnborg machines with more than one CPU. 2495e279b6c1SSam Ravnborg 2496e279b6c1SSam Ravnborg In order to use APM, you will need supporting software. For location 2497151f4e2bSMauro Carvalho Chehab and more information, read <file:Documentation/power/apm-acpi.rst> 24982dc98fd3SMichael Witten and the Battery Powered Linux mini-HOWTO, available from 2499e279b6c1SSam Ravnborg <http://www.tldp.org/docs.html#howto>. 2500e279b6c1SSam Ravnborg 2501e279b6c1SSam Ravnborg This driver does not spin down disk drives (see the hdparm(8) 2502e279b6c1SSam Ravnborg manpage ("man 8 hdparm") for that), and it doesn't turn off 2503e279b6c1SSam Ravnborg VESA-compliant "green" monitors. 2504e279b6c1SSam Ravnborg 2505e279b6c1SSam Ravnborg This driver does not support the TI 4000M TravelMate and the ACER 2506e279b6c1SSam Ravnborg 486/DX4/75 because they don't have compliant BIOSes. Many "green" 2507e279b6c1SSam Ravnborg desktop machines also don't have compliant BIOSes, and this driver 2508e279b6c1SSam Ravnborg may cause those machines to panic during the boot phase. 2509e279b6c1SSam Ravnborg 2510e279b6c1SSam Ravnborg Generally, if you don't have a battery in your machine, there isn't 2511e279b6c1SSam Ravnborg much point in using this driver and you should say N. If you get 2512e279b6c1SSam Ravnborg random kernel OOPSes or reboots that don't seem to be related to 2513e279b6c1SSam Ravnborg anything, try disabling/enabling this option (or disabling/enabling 2514e279b6c1SSam Ravnborg APM in your BIOS). 2515e279b6c1SSam Ravnborg 2516e279b6c1SSam Ravnborg Some other things you should try when experiencing seemingly random, 2517e279b6c1SSam Ravnborg "weird" problems: 2518e279b6c1SSam Ravnborg 2519e279b6c1SSam Ravnborg 1) make sure that you have enough swap space and that it is 2520e279b6c1SSam Ravnborg enabled. 2521e279b6c1SSam Ravnborg 2) pass the "no-hlt" option to the kernel 2522e279b6c1SSam Ravnborg 3) switch on floating point emulation in the kernel and pass 2523e279b6c1SSam Ravnborg the "no387" option to the kernel 2524e279b6c1SSam Ravnborg 4) pass the "floppy=nodma" option to the kernel 2525e279b6c1SSam Ravnborg 5) pass the "mem=4M" option to the kernel (thereby disabling 2526e279b6c1SSam Ravnborg all but the first 4 MB of RAM) 2527e279b6c1SSam Ravnborg 6) make sure that the CPU is not over clocked. 2528e279b6c1SSam Ravnborg 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/> 2529e279b6c1SSam Ravnborg 8) disable the cache from your BIOS settings 2530e279b6c1SSam Ravnborg 9) install a fan for the video card or exchange video RAM 2531e279b6c1SSam Ravnborg 10) install a better fan for the CPU 2532e279b6c1SSam Ravnborg 11) exchange RAM chips 2533e279b6c1SSam Ravnborg 12) exchange the motherboard. 2534e279b6c1SSam Ravnborg 2535e279b6c1SSam Ravnborg To compile this driver as a module, choose M here: the 2536e279b6c1SSam Ravnborg module will be called apm. 2537e279b6c1SSam Ravnborg 2538e279b6c1SSam Ravnborgif APM 2539e279b6c1SSam Ravnborg 2540e279b6c1SSam Ravnborgconfig APM_IGNORE_USER_SUSPEND 2541e279b6c1SSam Ravnborg bool "Ignore USER SUSPEND" 2542a7f7f624SMasahiro Yamada help 2543e279b6c1SSam Ravnborg This option will ignore USER SUSPEND requests. On machines with a 2544e279b6c1SSam Ravnborg compliant APM BIOS, you want to say N. However, on the NEC Versa M 2545e279b6c1SSam Ravnborg series notebooks, it is necessary to say Y because of a BIOS bug. 2546e279b6c1SSam Ravnborg 2547e279b6c1SSam Ravnborgconfig APM_DO_ENABLE 2548e279b6c1SSam Ravnborg bool "Enable PM at boot time" 2549a7f7f624SMasahiro Yamada help 2550e279b6c1SSam Ravnborg Enable APM features at boot time. From page 36 of the APM BIOS 2551e279b6c1SSam Ravnborg specification: "When disabled, the APM BIOS does not automatically 2552e279b6c1SSam Ravnborg power manage devices, enter the Standby State, enter the Suspend 2553e279b6c1SSam Ravnborg State, or take power saving steps in response to CPU Idle calls." 2554e279b6c1SSam Ravnborg This driver will make CPU Idle calls when Linux is idle (unless this 2555e279b6c1SSam Ravnborg feature is turned off -- see "Do CPU IDLE calls", below). This 2556e279b6c1SSam Ravnborg should always save battery power, but more complicated APM features 2557e279b6c1SSam Ravnborg will be dependent on your BIOS implementation. You may need to turn 2558e279b6c1SSam Ravnborg this option off if your computer hangs at boot time when using APM 2559e279b6c1SSam Ravnborg support, or if it beeps continuously instead of suspending. Turn 2560e279b6c1SSam Ravnborg this off if you have a NEC UltraLite Versa 33/C or a Toshiba 2561e279b6c1SSam Ravnborg T400CDT. This is off by default since most machines do fine without 2562e279b6c1SSam Ravnborg this feature. 2563e279b6c1SSam Ravnborg 2564e279b6c1SSam Ravnborgconfig APM_CPU_IDLE 2565dd8af076SLen Brown depends on CPU_IDLE 2566e279b6c1SSam Ravnborg bool "Make CPU Idle calls when idle" 2567a7f7f624SMasahiro Yamada help 2568e279b6c1SSam Ravnborg Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop. 2569e279b6c1SSam Ravnborg On some machines, this can activate improved power savings, such as 2570e279b6c1SSam Ravnborg a slowed CPU clock rate, when the machine is idle. These idle calls 2571e279b6c1SSam Ravnborg are made after the idle loop has run for some length of time (e.g., 2572e279b6c1SSam Ravnborg 333 mS). On some machines, this will cause a hang at boot time or 2573e279b6c1SSam Ravnborg whenever the CPU becomes idle. (On machines with more than one CPU, 2574e279b6c1SSam Ravnborg this option does nothing.) 2575e279b6c1SSam Ravnborg 2576e279b6c1SSam Ravnborgconfig APM_DISPLAY_BLANK 2577e279b6c1SSam Ravnborg bool "Enable console blanking using APM" 2578a7f7f624SMasahiro Yamada help 2579e279b6c1SSam Ravnborg Enable console blanking using the APM. Some laptops can use this to 2580e279b6c1SSam Ravnborg turn off the LCD backlight when the screen blanker of the Linux 2581e279b6c1SSam Ravnborg virtual console blanks the screen. Note that this is only used by 2582e279b6c1SSam Ravnborg the virtual console screen blanker, and won't turn off the backlight 2583e279b6c1SSam Ravnborg when using the X Window system. This also doesn't have anything to 2584e279b6c1SSam Ravnborg do with your VESA-compliant power-saving monitor. Further, this 2585e279b6c1SSam Ravnborg option doesn't work for all laptops -- it might not turn off your 2586e279b6c1SSam Ravnborg backlight at all, or it might print a lot of errors to the console, 2587e279b6c1SSam Ravnborg especially if you are using gpm. 2588e279b6c1SSam Ravnborg 2589e279b6c1SSam Ravnborgconfig APM_ALLOW_INTS 2590e279b6c1SSam Ravnborg bool "Allow interrupts during APM BIOS calls" 2591a7f7f624SMasahiro Yamada help 2592e279b6c1SSam Ravnborg Normally we disable external interrupts while we are making calls to 2593e279b6c1SSam Ravnborg the APM BIOS as a measure to lessen the effects of a badly behaving 2594e279b6c1SSam Ravnborg BIOS implementation. The BIOS should reenable interrupts if it 2595e279b6c1SSam Ravnborg needs to. Unfortunately, some BIOSes do not -- especially those in 2596e279b6c1SSam Ravnborg many of the newer IBM Thinkpads. If you experience hangs when you 2597e279b6c1SSam Ravnborg suspend, try setting this to Y. Otherwise, say N. 2598e279b6c1SSam Ravnborg 2599e279b6c1SSam Ravnborgendif # APM 2600e279b6c1SSam Ravnborg 2601bb0a56ecSDave Jonessource "drivers/cpufreq/Kconfig" 2602e279b6c1SSam Ravnborg 2603e279b6c1SSam Ravnborgsource "drivers/cpuidle/Kconfig" 2604e279b6c1SSam Ravnborg 260527471fdbSAndy Henroidsource "drivers/idle/Kconfig" 260627471fdbSAndy Henroid 2607e279b6c1SSam Ravnborgendmenu 2608e279b6c1SSam Ravnborg 2609e279b6c1SSam Ravnborg 2610e279b6c1SSam Ravnborgmenu "Bus options (PCI etc.)" 2611e279b6c1SSam Ravnborg 2612e279b6c1SSam Ravnborgchoice 2613e279b6c1SSam Ravnborg prompt "PCI access mode" 2614efefa6f6SIngo Molnar depends on X86_32 && PCI 2615e279b6c1SSam Ravnborg default PCI_GOANY 2616a7f7f624SMasahiro Yamada help 2617e279b6c1SSam Ravnborg On PCI systems, the BIOS can be used to detect the PCI devices and 2618e279b6c1SSam Ravnborg determine their configuration. However, some old PCI motherboards 2619e279b6c1SSam Ravnborg have BIOS bugs and may crash if this is done. Also, some embedded 2620e279b6c1SSam Ravnborg PCI-based systems don't have any BIOS at all. Linux can also try to 2621e279b6c1SSam Ravnborg detect the PCI hardware directly without using the BIOS. 2622e279b6c1SSam Ravnborg 2623e279b6c1SSam Ravnborg With this option, you can specify how Linux should detect the 2624e279b6c1SSam Ravnborg PCI devices. If you choose "BIOS", the BIOS will be used, 2625e279b6c1SSam Ravnborg if you choose "Direct", the BIOS won't be used, and if you 2626e279b6c1SSam Ravnborg choose "MMConfig", then PCI Express MMCONFIG will be used. 2627e279b6c1SSam Ravnborg If you choose "Any", the kernel will try MMCONFIG, then the 2628e279b6c1SSam Ravnborg direct access method and falls back to the BIOS if that doesn't 2629e279b6c1SSam Ravnborg work. If unsure, go with the default, which is "Any". 2630e279b6c1SSam Ravnborg 2631e279b6c1SSam Ravnborgconfig PCI_GOBIOS 2632e279b6c1SSam Ravnborg bool "BIOS" 2633e279b6c1SSam Ravnborg 2634e279b6c1SSam Ravnborgconfig PCI_GOMMCONFIG 2635e279b6c1SSam Ravnborg bool "MMConfig" 2636e279b6c1SSam Ravnborg 2637e279b6c1SSam Ravnborgconfig PCI_GODIRECT 2638e279b6c1SSam Ravnborg bool "Direct" 2639e279b6c1SSam Ravnborg 26403ef0e1f8SAndres Salomonconfig PCI_GOOLPC 264176fb6570SDaniel Drake bool "OLPC XO-1" 26423ef0e1f8SAndres Salomon depends on OLPC 26433ef0e1f8SAndres Salomon 26442bdd1b03SAndres Salomonconfig PCI_GOANY 26452bdd1b03SAndres Salomon bool "Any" 26462bdd1b03SAndres Salomon 2647e279b6c1SSam Ravnborgendchoice 2648e279b6c1SSam Ravnborg 2649e279b6c1SSam Ravnborgconfig PCI_BIOS 26503c2362e6SHarvey Harrison def_bool y 2651efefa6f6SIngo Molnar depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY) 2652e279b6c1SSam Ravnborg 2653e279b6c1SSam Ravnborg# x86-64 doesn't support PCI BIOS access from long mode so always go direct. 2654e279b6c1SSam Ravnborgconfig PCI_DIRECT 26553c2362e6SHarvey Harrison def_bool y 26560aba496fSShaohua Li depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG)) 2657e279b6c1SSam Ravnborg 2658e279b6c1SSam Ravnborgconfig PCI_MMCONFIG 2659b45c9f36SJan Kiszka bool "Support mmconfig PCI config space access" if X86_64 2660b45c9f36SJan Kiszka default y 26614590d98fSAndy Shevchenko depends on PCI && (ACPI || JAILHOUSE_GUEST) 2662b45c9f36SJan Kiszka depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG) 2663e279b6c1SSam Ravnborg 26643ef0e1f8SAndres Salomonconfig PCI_OLPC 26652bdd1b03SAndres Salomon def_bool y 26662bdd1b03SAndres Salomon depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY) 26673ef0e1f8SAndres Salomon 2668b5401a96SAlex Nixonconfig PCI_XEN 2669b5401a96SAlex Nixon def_bool y 2670b5401a96SAlex Nixon depends on PCI && XEN 2671b5401a96SAlex Nixon 26728364e1f8SJan Kiszkaconfig MMCONF_FAM10H 26738364e1f8SJan Kiszka def_bool y 26748364e1f8SJan Kiszka depends on X86_64 && PCI_MMCONFIG && ACPI 2675e279b6c1SSam Ravnborg 26763f6ea84aSIra W. Snyderconfig PCI_CNB20LE_QUIRK 26776a108a14SDavid Rientjes bool "Read CNB20LE Host Bridge Windows" if EXPERT 26786ea30386SKees Cook depends on PCI 26793f6ea84aSIra W. Snyder help 26803f6ea84aSIra W. Snyder Read the PCI windows out of the CNB20LE host bridge. This allows 26813f6ea84aSIra W. Snyder PCI hotplug to work on systems with the CNB20LE chipset which do 26823f6ea84aSIra W. Snyder not have ACPI. 26833f6ea84aSIra W. Snyder 268464a5fed6SBjorn Helgaas There's no public spec for this chipset, and this functionality 268564a5fed6SBjorn Helgaas is known to be incomplete. 268664a5fed6SBjorn Helgaas 268764a5fed6SBjorn Helgaas You should say N unless you know you need this. 268864a5fed6SBjorn Helgaas 26893a495511SWilliam Breathitt Grayconfig ISA_BUS 269017a2a129SWilliam Breathitt Gray bool "ISA bus support on modern systems" if EXPERT 26913a495511SWilliam Breathitt Gray help 269217a2a129SWilliam Breathitt Gray Expose ISA bus device drivers and options available for selection and 269317a2a129SWilliam Breathitt Gray configuration. Enable this option if your target machine has an ISA 269417a2a129SWilliam Breathitt Gray bus. ISA is an older system, displaced by PCI and newer bus 269517a2a129SWilliam Breathitt Gray architectures -- if your target machine is modern, it probably does 269617a2a129SWilliam Breathitt Gray not have an ISA bus. 26973a495511SWilliam Breathitt Gray 26983a495511SWilliam Breathitt Gray If unsure, say N. 26993a495511SWilliam Breathitt Gray 27001c00f016SDavid Rientjes# x86_64 have no ISA slots, but can have ISA-style DMA. 2701e279b6c1SSam Ravnborgconfig ISA_DMA_API 27021c00f016SDavid Rientjes bool "ISA-style DMA support" if (X86_64 && EXPERT) 27031c00f016SDavid Rientjes default y 27041c00f016SDavid Rientjes help 27051c00f016SDavid Rientjes Enables ISA-style DMA support for devices requiring such controllers. 27061c00f016SDavid Rientjes If unsure, say Y. 2707e279b6c1SSam Ravnborg 270851e68d05SLinus Torvaldsif X86_32 270951e68d05SLinus Torvalds 2710e279b6c1SSam Ravnborgconfig ISA 2711e279b6c1SSam Ravnborg bool "ISA support" 2712a7f7f624SMasahiro Yamada help 2713e279b6c1SSam Ravnborg Find out whether you have ISA slots on your motherboard. ISA is the 2714e279b6c1SSam Ravnborg name of a bus system, i.e. the way the CPU talks to the other stuff 2715e279b6c1SSam Ravnborg inside your box. Other bus systems are PCI, EISA, MicroChannel 2716e279b6c1SSam Ravnborg (MCA) or VESA. ISA is an older system, now being displaced by PCI; 2717e279b6c1SSam Ravnborg newer boards don't support it. If you have ISA, say Y, otherwise N. 2718e279b6c1SSam Ravnborg 2719e279b6c1SSam Ravnborgconfig SCx200 2720e279b6c1SSam Ravnborg tristate "NatSemi SCx200 support" 2721a7f7f624SMasahiro Yamada help 2722e279b6c1SSam Ravnborg This provides basic support for National Semiconductor's 2723e279b6c1SSam Ravnborg (now AMD's) Geode processors. The driver probes for the 2724e279b6c1SSam Ravnborg PCI-IDs of several on-chip devices, so its a good dependency 2725e279b6c1SSam Ravnborg for other scx200_* drivers. 2726e279b6c1SSam Ravnborg 2727e279b6c1SSam Ravnborg If compiled as a module, the driver is named scx200. 2728e279b6c1SSam Ravnborg 2729e279b6c1SSam Ravnborgconfig SCx200HR_TIMER 2730e279b6c1SSam Ravnborg tristate "NatSemi SCx200 27MHz High-Resolution Timer Support" 2731592913ecSJohn Stultz depends on SCx200 2732e279b6c1SSam Ravnborg default y 2733a7f7f624SMasahiro Yamada help 2734e279b6c1SSam Ravnborg This driver provides a clocksource built upon the on-chip 2735e279b6c1SSam Ravnborg 27MHz high-resolution timer. Its also a workaround for 2736e279b6c1SSam Ravnborg NSC Geode SC-1100's buggy TSC, which loses time when the 2737e279b6c1SSam Ravnborg processor goes idle (as is done by the scheduler). The 2738e279b6c1SSam Ravnborg other workaround is idle=poll boot option. 2739e279b6c1SSam Ravnborg 27403ef0e1f8SAndres Salomonconfig OLPC 27413ef0e1f8SAndres Salomon bool "One Laptop Per Child support" 274254008979SThomas Gleixner depends on !X86_PAE 27433c554946SAndres Salomon select GPIOLIB 2744dc3119e7SThomas Gleixner select OF 274545bb1674SDaniel Drake select OF_PROMTREE 2746b4e51854SGrant Likely select IRQ_DOMAIN 27470c3d931bSLubomir Rintel select OLPC_EC 2748a7f7f624SMasahiro Yamada help 27493ef0e1f8SAndres Salomon Add support for detecting the unique features of the OLPC 27503ef0e1f8SAndres Salomon XO hardware. 27513ef0e1f8SAndres Salomon 2752a3128588SDaniel Drakeconfig OLPC_XO1_PM 2753a3128588SDaniel Drake bool "OLPC XO-1 Power Management" 2754fa112cf1SBorislav Petkov depends on OLPC && MFD_CS5535=y && PM_SLEEP 2755a7f7f624SMasahiro Yamada help 275697c4cb71SDaniel Drake Add support for poweroff and suspend of the OLPC XO-1 laptop. 2757bf1ebf00SDaniel Drake 2758cfee9597SDaniel Drakeconfig OLPC_XO1_RTC 2759cfee9597SDaniel Drake bool "OLPC XO-1 Real Time Clock" 2760cfee9597SDaniel Drake depends on OLPC_XO1_PM && RTC_DRV_CMOS 2761a7f7f624SMasahiro Yamada help 2762cfee9597SDaniel Drake Add support for the XO-1 real time clock, which can be used as a 2763cfee9597SDaniel Drake programmable wakeup source. 2764cfee9597SDaniel Drake 27657feda8e9SDaniel Drakeconfig OLPC_XO1_SCI 27667feda8e9SDaniel Drake bool "OLPC XO-1 SCI extras" 276792e830f2SArnd Bergmann depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y 2768ed8e47feSRandy Dunlap depends on INPUT=y 2769d8d01a63SDaniel Drake select POWER_SUPPLY 2770a7f7f624SMasahiro Yamada help 27717feda8e9SDaniel Drake Add support for SCI-based features of the OLPC XO-1 laptop: 27727bc74b3dSDaniel Drake - EC-driven system wakeups 27737feda8e9SDaniel Drake - Power button 27747bc74b3dSDaniel Drake - Ebook switch 27752cf2baeaSDaniel Drake - Lid switch 2776e1040ac6SDaniel Drake - AC adapter status updates 2777e1040ac6SDaniel Drake - Battery status updates 27787feda8e9SDaniel Drake 2779a0f30f59SDaniel Drakeconfig OLPC_XO15_SCI 2780a0f30f59SDaniel Drake bool "OLPC XO-1.5 SCI extras" 2781d8d01a63SDaniel Drake depends on OLPC && ACPI 2782d8d01a63SDaniel Drake select POWER_SUPPLY 2783a7f7f624SMasahiro Yamada help 2784a0f30f59SDaniel Drake Add support for SCI-based features of the OLPC XO-1.5 laptop: 2785a0f30f59SDaniel Drake - EC-driven system wakeups 2786a0f30f59SDaniel Drake - AC adapter status updates 2787a0f30f59SDaniel Drake - Battery status updates 2788e279b6c1SSam Ravnborg 2789d4f3e350SEd Wildgooseconfig ALIX 2790d4f3e350SEd Wildgoose bool "PCEngines ALIX System Support (LED setup)" 2791d4f3e350SEd Wildgoose select GPIOLIB 2792a7f7f624SMasahiro Yamada help 2793d4f3e350SEd Wildgoose This option enables system support for the PCEngines ALIX. 2794d4f3e350SEd Wildgoose At present this just sets up LEDs for GPIO control on 2795d4f3e350SEd Wildgoose ALIX2/3/6 boards. However, other system specific setup should 2796d4f3e350SEd Wildgoose get added here. 2797d4f3e350SEd Wildgoose 2798d4f3e350SEd Wildgoose Note: You must still enable the drivers for GPIO and LED support 2799d4f3e350SEd Wildgoose (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs 2800d4f3e350SEd Wildgoose 2801d4f3e350SEd Wildgoose Note: You have to set alix.force=1 for boards with Award BIOS. 2802d4f3e350SEd Wildgoose 2803da4e3302SPhilip Prindevilleconfig NET5501 2804da4e3302SPhilip Prindeville bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)" 2805da4e3302SPhilip Prindeville select GPIOLIB 2806a7f7f624SMasahiro Yamada help 2807da4e3302SPhilip Prindeville This option enables system support for the Soekris Engineering net5501. 2808da4e3302SPhilip Prindeville 28093197059aSPhilip A. Prindevilleconfig GEOS 28103197059aSPhilip A. Prindeville bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)" 28113197059aSPhilip A. Prindeville select GPIOLIB 28123197059aSPhilip A. Prindeville depends on DMI 2813a7f7f624SMasahiro Yamada help 28143197059aSPhilip A. Prindeville This option enables system support for the Traverse Technologies GEOS. 28153197059aSPhilip A. Prindeville 28167d029125SVivien Didelotconfig TS5500 28177d029125SVivien Didelot bool "Technologic Systems TS-5500 platform support" 28187d029125SVivien Didelot depends on MELAN 28197d029125SVivien Didelot select CHECK_SIGNATURE 28207d029125SVivien Didelot select NEW_LEDS 28217d029125SVivien Didelot select LEDS_CLASS 2822a7f7f624SMasahiro Yamada help 28237d029125SVivien Didelot This option enables system support for the Technologic Systems TS-5500. 28247d029125SVivien Didelot 2825e279b6c1SSam Ravnborgendif # X86_32 2826e279b6c1SSam Ravnborg 282723ac4ae8SAndreas Herrmannconfig AMD_NB 2828e279b6c1SSam Ravnborg def_bool y 28290e152cd7SBorislav Petkov depends on CPU_SUP_AMD && PCI 2830e279b6c1SSam Ravnborg 2831e279b6c1SSam Ravnborgendmenu 2832e279b6c1SSam Ravnborg 2833e279b6c1SSam Ravnborg 28341572497cSChristoph Hellwigmenu "Binary Emulations" 2835e279b6c1SSam Ravnborg 2836e279b6c1SSam Ravnborgconfig IA32_EMULATION 2837e279b6c1SSam Ravnborg bool "IA32 Emulation" 2838e279b6c1SSam Ravnborg depends on X86_64 283939f88911SIngo Molnar select ARCH_WANT_OLD_COMPAT_IPC 2840d1603990SRandy Dunlap select BINFMT_ELF 284139f88911SIngo Molnar select COMPAT_OLD_SIGACTION 2842a7f7f624SMasahiro Yamada help 28435fd92e65SH. J. Lu Include code to run legacy 32-bit programs under a 28445fd92e65SH. J. Lu 64-bit kernel. You should likely turn this on, unless you're 28455fd92e65SH. J. Lu 100% sure that you don't have any 32-bit programs left. 2846e279b6c1SSam Ravnborg 2847e279b6c1SSam Ravnborgconfig IA32_AOUT 2848e279b6c1SSam Ravnborg tristate "IA32 a.out support" 28496b213e1bSDavid Woodhouse depends on IA32_EMULATION 2850eac61655SBorislav Petkov depends on BROKEN 2851a7f7f624SMasahiro Yamada help 2852e279b6c1SSam Ravnborg Support old a.out binaries in the 32bit emulation. 2853e279b6c1SSam Ravnborg 285483a44a4fSMasahiro Yamadaconfig X86_X32_ABI 28556ea30386SKees Cook bool "x32 ABI for 64-bit mode" 28569b54050bSBrian Gerst depends on X86_64 2857aaeed6ecSNathan Chancellor # llvm-objcopy does not convert x86_64 .note.gnu.property or 2858aaeed6ecSNathan Chancellor # compressed debug sections to x86_x32 properly: 2859aaeed6ecSNathan Chancellor # https://github.com/ClangBuiltLinux/linux/issues/514 2860aaeed6ecSNathan Chancellor # https://github.com/ClangBuiltLinux/linux/issues/1141 2861aaeed6ecSNathan Chancellor depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm) 2862a7f7f624SMasahiro Yamada help 28635fd92e65SH. J. Lu Include code to run binaries for the x32 native 32-bit ABI 28645fd92e65SH. J. Lu for 64-bit processors. An x32 process gets access to the 28655fd92e65SH. J. Lu full 64-bit register file and wide data path while leaving 28665fd92e65SH. J. Lu pointers at 32 bits for smaller memory footprint. 28675fd92e65SH. J. Lu 2868953fee1dSIngo Molnarconfig COMPAT_32 2869953fee1dSIngo Molnar def_bool y 2870953fee1dSIngo Molnar depends on IA32_EMULATION || X86_32 2871953fee1dSIngo Molnar select HAVE_UID16 2872953fee1dSIngo Molnar select OLD_SIGSUSPEND3 2873953fee1dSIngo Molnar 2874e279b6c1SSam Ravnborgconfig COMPAT 28753c2362e6SHarvey Harrison def_bool y 287683a44a4fSMasahiro Yamada depends on IA32_EMULATION || X86_X32_ABI 2877e279b6c1SSam Ravnborg 28783120e25eSJan Beulichif COMPAT 2879e279b6c1SSam Ravnborgconfig COMPAT_FOR_U64_ALIGNMENT 28803120e25eSJan Beulich def_bool y 2881e279b6c1SSam Ravnborg 2882e279b6c1SSam Ravnborgconfig SYSVIPC_COMPAT 28833c2362e6SHarvey Harrison def_bool y 28843120e25eSJan Beulich depends on SYSVIPC 28853120e25eSJan Beulichendif 2886ee009e4aSDavid Howells 2887e279b6c1SSam Ravnborgendmenu 2888e279b6c1SSam Ravnborg 2889e279b6c1SSam Ravnborg 2890e5beae16SKeith Packardconfig HAVE_ATOMIC_IOMAP 2891e5beae16SKeith Packard def_bool y 2892e5beae16SKeith Packard depends on X86_32 2893e5beae16SKeith Packard 2894edf88417SAvi Kivitysource "arch/x86/kvm/Kconfig" 28955e8ebd84SJason A. Donenfeld 28965e8ebd84SJason A. Donenfeldsource "arch/x86/Kconfig.assembler" 2897